85 results on '"Schäffler, A."'
Search Results
2. Regulation of Cathelicidin Antimicrobial Peptide (CAMP) Gene Expression by TNFα and cfDNA in Adipocytes
- Author
-
Alexandra Höpfinger, Andreas Schmid, Leonie Schweitzer, Marissa Patz, Anja Weber, Andreas Schäffler, and Thomas Karrasch
- Subjects
TNFα ,cfDNA ,TLR (toll-like receptor) 9 ,cathelicidin anti-microbial peptide ,adipocyte ,adipose tissue ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Understanding the complex interactions between metabolism and the immune system (“metaflammation”) is crucial for the identification of key immunomodulatory factors as potential therapeutic targets in obesity and in cardiovascular diseases. Cathelicidin antimicrobial peptide (CAMP) is an important factor of innate immunity and is expressed in adipocytes. CAMP, therefore, might play a role as an adipokine in metaflammation and adipose inflammation. TNFα, cell-free nucleic acids (cfDNA), and toll-like receptor (TLR) 9 are components of the innate immune system and are functionally active in adipose tissue. The aim of the present study was to investigate the impact of TNFα and cfDNA on CAMP expression in adipocytes. Since cfDNA acts as a physiological TLR9 agonist, we additionally investigated TLR9-mediated CAMP regulation in adipocytes and adipose tissue. CAMP gene expression in murine 3T3-L1 and human SGBS adipocytes and in murine and human adipose tissues was quantified by real-time PCR. Adipocyte inflammation was induced in vitro by TNFα and cfDNA stimulation. Serum CAMP concentrations in TLR9 knockout (KO) and in wildtype mice were quantified by ELISA. In primary adipocytes of wildtype and TLR9 KO mice, CAMP gene expression was quantified by real-time PCR. CAMP gene expression was considerably increased in 3T3-L1 and SGBS adipocytes during differentiation. TNFα significantly induced CAMP gene expression in mature adipocytes, which was effectively antagonized by inhibition of PI3K signaling. Cell-free nucleic acids (cfDNA) significantly impaired CAMP gene expression, whereas synthetic agonistic and antagonistic TLR9 ligands had no effect. CAMP and TLR9 gene expression were correlated positively in murine and human subcutaneous but not in intra-abdominal/visceral adipose tissues. Male TLR9 knockout mice exhibited lower systemic CAMP concentrations than wildtype mice. CAMP gene expression levels in primary adipocytes did not significantly differ between wildtype and TLR9 KO mice. These findings suggest a regulatory role of inflammatory mediators, such as TNFα and cfDNA, in adipocytic CAMP expression as a novel putative molecular mechanism in adipose tissue innate immunity.
- Published
- 2023
- Full Text
- View/download PDF
3. CTRP-3 Regulates NOD1-mediated Inflammation and NOD1 Expression in Adipocytes and Adipose Tissue
- Author
-
Schmid, Andreas, Schäffler, Andreas, and Karrasch, Thomas
- Published
- 2021
- Full Text
- View/download PDF
4. Circulating Concentrations of Cathelicidin Anti-Microbial Peptide (CAMP) Are Increased during Oral Glucose Tolerance Test
- Author
-
Alexandra Höpfinger, Thomas Karrasch, Andreas Schäffler, and Andreas Schmid
- Subjects
Cathelicidin antimicrobial peptide, CAMP ,adipokine ,oral glucose tolerance test, OGTT ,adipocyte ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Recent investigation has revealed the significant role of Cathelicidin antimicrobial peptide (CAMP) in infection defense and innate immunity processes in adipose tissue. Meanwhile, knowledge of its regulation and functions in metabolic contexts as an adipokine remains sparce. The present study investigated the postprandial regulation of circulating CAMP levels during oral glucose tolerance tests (OGTTs). Eighty-six metabolically healthy volunteers participated in a standardized 75 g-2 h-OGTT setting. The effects of exogenous glucose, insulin, and incretins on CAMP expression in human adipocyte culture (cell-line SGBS) were studied in vitro. CAMP concentrations in blood serum samples were measured by ELISA techniques and adipocyte gene expression levels were quantified by real-time PCR. Of note, base-line CAMP serum quantities were negatively correlated with HDL cholesterol levels as well as with the anti-inflammatory adipokine adiponectin. During the 2 h following glucose ingestion, a significant rise in circulating CAMP concentrations was observed in considerable contrast to reduced quantities of fatty acid binding proteins (FABP) 2 and 4 and dipeptidyl peptidase 4 (DPP4). In SGBS adipocytes, neither differing glucose levels nor insulin or incretin treatment significantly induced CAMP mRNA levels. According to our data, glucose represents a positive postprandial regulator of systemic CAMP. This effect apparently is not mediated by the regulatory impact of glucose metabolism on adipocyte CAMP expression.
- Published
- 2023
- Full Text
- View/download PDF
5. Circulating Levels of Cathelicidin Antimicrobial Peptide (CAMP) Are Affected by Oral Lipid Ingestion
- Author
-
Alexandra Höpfinger, Thomas Karrasch, Andreas Schäffler, and Andreas Schmid
- Subjects
CAMP ,cathelicidin ,bile acid ,lipid ,adipocyte ,Nutrition. Foods and food supply ,TX341-641 - Abstract
Introduction: Obesity and related diseases are among the main public health issues in the western world. They are thought to be caused by a state of chronic, low-grade inflammation. Cathelicidin antimicrobial peptide (CAMP) was recently discovered to be expressed and secreted by adipocytes. Representing a novel immunomodulatory adipokine, CAMP might play an important role in the complex interaction between metabolism and inflammation. Methods: In a cohort of 80 volunteers, serum samples were collected prior to, and 2 h, 4 h, and 6 h after, oral lipid ingestion. CAMP, fatty acid binding proteins 2 and 4 (FABP-2/-4), and dipeptidylpeptidase-4 (DPP-4) serum concentrations were measured via ELISA. Human Simpson–Golabi–Behmel syndrome (SGBS) adipocytes were treated with free fatty acids, and gene expression levels of CAMP, FABP-4, and DPP-4 were quantified by RT-PCR. Results: The mean base-line CAMP serum concentration was 55.78 ± 29.26 ng/mL, with a range of 10.77–146.24 ng/mL. Interestingly, CAMP serum levels were positively correlated with LDL cholesterol, but negatively correlated with HDL cholesterol and adiponectin. Men exhibited higher CAMP serum concentrations than women, an effect apparently linked to oral contraception in the majority of female participants. In both genders, CAMP serum concentrations significantly decreased in a stepwise manner 4 h and 6 h after oral lipid ingestion. This decline was paralleled by a rise of serum bile acid and triglyceride levels upon lipid ingestion. In human SGBS adipocytes, treatment with free fatty acids did not affect CAMP gene expression, but increased FABP-4 gene expression. Conclusions: In conclusion, systemic levels of the antimicrobial peptide and novel adipokine CAMP are significantly decreased upon oral lipid ingestion. While this decline might be linked to the simultaneous increase in bile acids, the underlying mechanisms remain to be elucidated. Furthermore, CAMP might indicate a putative novel cardiovascular biomarker of both inflammatory and metabolic relevance in metaflammation and adipose inflammation.
- Published
- 2023
- Full Text
- View/download PDF
6. Toll-like Receptor 7 (TLR7) Is Expressed in Adipocytes and the Pharmacological TLR7 Agonist Imiquimod and Adipocyte-Derived Cell-Free Nucleic Acids (cfDNA) Regulate Adipocyte Function
- Author
-
Miriam Thomalla, Andreas Schmid, Julia Hehner, Sebastian Koehler, Elena Neumann, Ulf Müller-Ladner, Andreas Schäffler, and Thomas Karrasch
- Subjects
TLR7 ,adipocyte ,inflammation ,adipose tissue ,adipokine ,pattern recognition receptor ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
Endosome-localized Toll-like receptors (TLRs) 3 and 9 are expressed and functionally active in adipocytes. The functionality and role of TLR7 in adipocyte biology and innate immunity of adipose tissue (AT) is poorly characterized. We analyzed TLR7 mRNA and protein expression in murine 3T3-L1 and primary adipocytes, in co-cultures of 3T3-L1 adipocytes with murine J774A.1 monocytes and in human AT. The effects of TLR7 agonists imiquimod (IMQ) and cell-free nucleic acids (cfDNA) on adipokine concentration in cell-culture supernatants and gene expression profile were investigated. We found that TLR7 expression is strongly induced during adipocyte differentiation. TLR7 gene expression in adipocytes and AT stroma-vascular cells (SVC) seems to be independent of TLR9. IMQ downregulates resistin concentration in adipocyte cell-culture supernatants and modulates gene expression of glucose transporter Glut4. Adipocyte-derived cfDNA reduces adiponectin and resistin in cell-culture supernatants and potentially inhibits Glut4 gene expression. The responsiveness of 3T3-L1 adipocytes to imiquimod is preserved in co-culture with J774A.1 monocytes. Obesity-related, adipocyte-derived cfDNA engages adipocytic pattern recognition receptors (PRRs), modulating AT immune and metabolic homeostasis during adipose inflammation.
- Published
- 2022
- Full Text
- View/download PDF
7. Circulating Levels of Cathelicidin Antimicrobial Peptide (CAMP) Are Affected by Oral Lipid Ingestion
- Author
-
Schmid, Alexandra Höpfinger, Thomas Karrasch, Andreas Schäffler, and Andreas
- Subjects
CAMP ,cathelicidin ,bile acid ,lipid ,adipocyte - Abstract
Introduction: Obesity and related diseases are among the main public health issues in the western world. They are thought to be caused by a state of chronic, low-grade inflammation. Cathelicidin antimicrobial peptide (CAMP) was recently discovered to be expressed and secreted by adipocytes. Representing a novel immunomodulatory adipokine, CAMP might play an important role in the complex interaction between metabolism and inflammation. Methods: In a cohort of 80 volunteers, serum samples were collected prior to, and 2 h, 4 h, and 6 h after, oral lipid ingestion. CAMP, fatty acid binding proteins 2 and 4 (FABP-2/-4), and dipeptidylpeptidase-4 (DPP-4) serum concentrations were measured via ELISA. Human Simpson–Golabi–Behmel syndrome (SGBS) adipocytes were treated with free fatty acids, and gene expression levels of CAMP, FABP-4, and DPP-4 were quantified by RT-PCR. Results: The mean base-line CAMP serum concentration was 55.78 ± 29.26 ng/mL, with a range of 10.77–146.24 ng/mL. Interestingly, CAMP serum levels were positively correlated with LDL cholesterol, but negatively correlated with HDL cholesterol and adiponectin. Men exhibited higher CAMP serum concentrations than women, an effect apparently linked to oral contraception in the majority of female participants. In both genders, CAMP serum concentrations significantly decreased in a stepwise manner 4 h and 6 h after oral lipid ingestion. This decline was paralleled by a rise of serum bile acid and triglyceride levels upon lipid ingestion. In human SGBS adipocytes, treatment with free fatty acids did not affect CAMP gene expression, but increased FABP-4 gene expression. Conclusions: In conclusion, systemic levels of the antimicrobial peptide and novel adipokine CAMP are significantly decreased upon oral lipid ingestion. While this decline might be linked to the simultaneous increase in bile acids, the underlying mechanisms remain to be elucidated. Furthermore, CAMP might indicate a putative novel cardiovascular biomarker of both inflammatory and metabolic relevance in metaflammation and adipose inflammation.
- Published
- 2023
- Full Text
- View/download PDF
8. Regulation of Cathelicidin Antimicrobial Peptide (CAMP) Gene Expression by TNFα and cfDNA in Adipocytes.
- Author
-
Höpfinger, Alexandra, Schmid, Andreas, Schweitzer, Leonie, Patz, Marissa, Weber, Anja, Schäffler, Andreas, and Karrasch, Thomas
- Subjects
ANTIMICROBIAL peptides ,GENE expression ,ADIPOGENESIS ,ADIPOSE tissues ,CELL-free DNA ,FAT cells ,INFLAMMATORY mediators - Abstract
Understanding the complex interactions between metabolism and the immune system ("metaflammation") is crucial for the identification of key immunomodulatory factors as potential therapeutic targets in obesity and in cardiovascular diseases. Cathelicidin antimicrobial peptide (CAMP) is an important factor of innate immunity and is expressed in adipocytes. CAMP, therefore, might play a role as an adipokine in metaflammation and adipose inflammation. TNFα, cell-free nucleic acids (cfDNA), and toll-like receptor (TLR) 9 are components of the innate immune system and are functionally active in adipose tissue. The aim of the present study was to investigate the impact of TNFα and cfDNA on CAMP expression in adipocytes. Since cfDNA acts as a physiological TLR9 agonist, we additionally investigated TLR9-mediated CAMP regulation in adipocytes and adipose tissue. CAMP gene expression in murine 3T3-L1 and human SGBS adipocytes and in murine and human adipose tissues was quantified by real-time PCR. Adipocyte inflammation was induced in vitro by TNFα and cfDNA stimulation. Serum CAMP concentrations in TLR9 knockout (KO) and in wildtype mice were quantified by ELISA. In primary adipocytes of wildtype and TLR9 KO mice, CAMP gene expression was quantified by real-time PCR. CAMP gene expression was considerably increased in 3T3-L1 and SGBS adipocytes during differentiation. TNFα significantly induced CAMP gene expression in mature adipocytes, which was effectively antagonized by inhibition of PI3K signaling. Cell-free nucleic acids (cfDNA) significantly impaired CAMP gene expression, whereas synthetic agonistic and antagonistic TLR9 ligands had no effect. CAMP and TLR9 gene expression were correlated positively in murine and human subcutaneous but not in intra-abdominal/visceral adipose tissues. Male TLR9 knockout mice exhibited lower systemic CAMP concentrations than wildtype mice. CAMP gene expression levels in primary adipocytes did not significantly differ between wildtype and TLR9 KO mice. These findings suggest a regulatory role of inflammatory mediators, such as TNFα and cfDNA, in adipocytic CAMP expression as a novel putative molecular mechanism in adipose tissue innate immunity. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
9. C1q/TNF-Related Protein 3 (CTRP-3) Deficiency of Adipocytes Affects White Adipose Tissue Mass but Not Systemic CTRP-3 Concentrations
- Author
-
Andreas Schmid, Martin Roderfeld, Jonas Gehl, Elke Roeb, Andrea Nist, Ho-Ryun Chung, Thorsten Stiewe, Thomas Karrasch, and Andreas Schäffler
- Subjects
CTRP-3 knockout ,adipocyte ,adipose tissue ,adipokine ,inflammation ,Biology (General) ,QH301-705.5 ,Chemistry ,QD1-999 - Abstract
CTRP-3 (C1q/TNF-related protein-3) is an adipokine with endocrine and immunological function. The impact of adipocyte CTRP-3 production on systemic CTRP-3 concentrations and on adipocyte biology is unknown. A murine model of adipocyte CTRP-3 knockout (KO) was established (via the Cre/loxP system). Serum adipokine levels were quantified by ELISA and adipose tissue (AT) gene expression by real-time PCR. Preadipocytes were isolated from AT and differentiated into adipocytes. Comparative transcriptome analysis was applied in adipocytes and liver tissue. Body weight and AT mass were reduced in CTRP-3 KO mice together with decreased serum leptin. In primary cells from visceral AT of KO mice, expression of adiponectin, progranulin, and resistin was induced, while peroxisome proliferator activated receptor γ (PPARγ) was decreased. M1/M2 macrophage polarization markers were shifted to a more anti-inflammatory phenotype. CTRP-3 expression in AT did not contribute to serum concentrations. AT and liver morphology remained unaffected by CTRP-3 KO. Myelin transcription factor 1-like (Myt1l) was identified as a highly upregulated gene. In conclusion, adipocyte CTRP-3 has a role in adipogenesis and AT weight gain whereas adipocyte differentiation is not impaired by CTRP-3 deficiency. Since no effects on circulating CTRP-3 levels were observed, the impact of adipocyte CTRP-3 KO is limited to adipose tissue. Modified AT gene expression indicates a rather anti-inflammatory phenotype.
- Published
- 2021
- Full Text
- View/download PDF
10. Circulating Concentrations of Cathelicidin Anti-Microbial Peptide (CAMP) Are Increased during Oral Glucose Tolerance Test.
- Author
-
Höpfinger, Alexandra, Karrasch, Thomas, Schäffler, Andreas, and Schmid, Andreas
- Subjects
GLUCOSE tolerance tests ,PEPTIDES ,ANTIMICROBIAL peptides ,CD26 antigen ,ANTI-infective agents ,FAT cells ,CELL culture ,GESTATIONAL diabetes ,ADIPOGENESIS - Abstract
Recent investigation has revealed the significant role of Cathelicidin antimicrobial peptide (CAMP) in infection defense and innate immunity processes in adipose tissue. Meanwhile, knowledge of its regulation and functions in metabolic contexts as an adipokine remains sparce. The present study investigated the postprandial regulation of circulating CAMP levels during oral glucose tolerance tests (OGTTs). Eighty-six metabolically healthy volunteers participated in a standardized 75 g-2 h-OGTT setting. The effects of exogenous glucose, insulin, and incretins on CAMP expression in human adipocyte culture (cell-line SGBS) were studied in vitro. CAMP concentrations in blood serum samples were measured by ELISA techniques and adipocyte gene expression levels were quantified by real-time PCR. Of note, base-line CAMP serum quantities were negatively correlated with HDL cholesterol levels as well as with the anti-inflammatory adipokine adiponectin. During the 2 h following glucose ingestion, a significant rise in circulating CAMP concentrations was observed in considerable contrast to reduced quantities of fatty acid binding proteins (FABP) 2 and 4 and dipeptidyl peptidase 4 (DPP4). In SGBS adipocytes, neither differing glucose levels nor insulin or incretin treatment significantly induced CAMP mRNA levels. According to our data, glucose represents a positive postprandial regulator of systemic CAMP. This effect apparently is not mediated by the regulatory impact of glucose metabolism on adipocyte CAMP expression. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
11. Circulating Levels of Cathelicidin Antimicrobial Peptide (CAMP) Are Affected by Oral Lipid Ingestion.
- Author
-
Höpfinger, Alexandra, Karrasch, Thomas, Schäffler, Andreas, and Schmid, Andreas
- Abstract
Introduction: Obesity and related diseases are among the main public health issues in the western world. They are thought to be caused by a state of chronic, low-grade inflammation. Cathelicidin antimicrobial peptide (CAMP) was recently discovered to be expressed and secreted by adipocytes. Representing a novel immunomodulatory adipokine, CAMP might play an important role in the complex interaction between metabolism and inflammation. Methods: In a cohort of 80 volunteers, serum samples were collected prior to, and 2 h, 4 h, and 6 h after, oral lipid ingestion. CAMP, fatty acid binding proteins 2 and 4 (FABP-2/-4), and dipeptidylpeptidase-4 (DPP-4) serum concentrations were measured via ELISA. Human Simpson–Golabi–Behmel syndrome (SGBS) adipocytes were treated with free fatty acids, and gene expression levels of CAMP, FABP-4, and DPP-4 were quantified by RT-PCR. Results: The mean base-line CAMP serum concentration was 55.78 ± 29.26 ng/mL, with a range of 10.77–146.24 ng/mL. Interestingly, CAMP serum levels were positively correlated with LDL cholesterol, but negatively correlated with HDL cholesterol and adiponectin. Men exhibited higher CAMP serum concentrations than women, an effect apparently linked to oral contraception in the majority of female participants. In both genders, CAMP serum concentrations significantly decreased in a stepwise manner 4 h and 6 h after oral lipid ingestion. This decline was paralleled by a rise of serum bile acid and triglyceride levels upon lipid ingestion. In human SGBS adipocytes, treatment with free fatty acids did not affect CAMP gene expression, but increased FABP-4 gene expression. Conclusions: In conclusion, systemic levels of the antimicrobial peptide and novel adipokine CAMP are significantly decreased upon oral lipid ingestion. While this decline might be linked to the simultaneous increase in bile acids, the underlying mechanisms remain to be elucidated. Furthermore, CAMP might indicate a putative novel cardiovascular biomarker of both inflammatory and metabolic relevance in metaflammation and adipose inflammation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
12. CTRP-3 Regulates NOD1-mediated Inflammation and NOD1 Expression in Adipocytes and Adipose Tissue
- Author
-
Andreas Schmid, Andreas Schäffler, and Thomas Karrasch
- Subjects
0301 basic medicine ,Lipopolysaccharides ,Male ,Chemokine ,NOD1 ,THP-1 Cells ,Immunology ,Subcutaneous Fat ,Adipose tissue ,Adipokine ,030209 endocrinology & metabolism ,Inflammation ,macrophage ,peptidoglycan ,Intra-Abdominal Fat ,adipocyte ,Proinflammatory cytokine ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Adipokines ,Adipocyte ,3T3-L1 Cells ,Nod1 Signaling Adaptor Protein ,medicine ,Adipocytes ,Immunology and Allergy ,Animals ,Humans ,Mice, Knockout ,biology ,Systemic Inflammatory Response Syndrome ,Cell biology ,adipose tissue ,body regions ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,chemistry ,biology.protein ,Cytokines ,Cytokine secretion ,Tumor necrosis factor alpha ,Original Article ,medicine.symptom ,Inflammation Mediators ,C1q/TNF-related protein-3 ,Signal Transduction - Abstract
The anti-inflammatory adipokine CTRP-3 might affect innate immune reactions such as NOD1. The impact of CTRP-3 on NOD1-mediated inflammation in adipocytes and monocytic cells as well as on NOD1 expression was investigated. Murine 3T3-L1 pre-adipocytes and adipocytes as well as human THP-1 monocyte-like cells were co-stimulated with the synthetic NOD1 agonist Tri-DAP and recombinant CTRP-3. Gonadal adipose tissue and primary adipocytes were obtained from a murine model carrying a knockout (KO) of CTRP-3 in adipocytes but not in stroma-vascular cells. Wildtype mice with lipopolysaccharide (LPS)-induced elevated NOD1 expression were treated with CTRP-3. Secreted inflammatory cytokines in cell supernatants were measured by ELISA and mRNA levels were quantified by RT-PCR. Pro-inflammatory chemokine and cytokine secretion (MCP-1, RANTES, TNFα) was induced by NOD1 activation in adipocytes and monocyte-like cells, and MCP-1 and RANTES release was effectively inhibited by pre-incubation of cells with CTRP-3. CTRP-3 also antagonized LPS-triggered induction of NOD1 gene expression in murine adipose tissue, whereas adipocyte CTRP-3 deficiency upregulated NOD1 expression in adipose tissue. CTRP-3 is an effective antagonist of peptidoglycan-induced, NOD1-mediated inflammation and of LPS-induced NOD1 expression. Since basal NOD1 expression is increased by adipocyte CTRP-3 deficiency, there have to be also inflammation-independent mechanisms of NOD1 expression regulation by CTRP-3.
- Published
- 2021
13. Regulation of CAMP (cathelicidin antimicrobial peptide) expression in adipocytes by TLR 2 and 4
- Author
-
Thomas Karrasch, Andreas Schmid, Alexandra Höpfinger, and Andreas Schäffler
- Subjects
Lipopolysaccharides ,Male ,STAT3 Transcription Factor ,lcsh:Immunologic diseases. Allergy ,0301 basic medicine ,MAPK/ERK pathway ,LPS ,Immunology ,Adipose tissue ,Microbiology ,Cell Line ,Lipopeptides ,Mice ,Phosphatidylinositol 3-Kinases ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Cathelicidins ,Toll-like receptor ,Adipocyte ,Gene expression ,Adipocytes ,Animals ,cathelicidin antimicrobial peptide ,Gonads ,Molecular Biology ,Sex Characteristics ,Chemistry ,Original Articles ,Cell Biology ,Toll-Like Receptor 2 ,adipose tissue ,Cell biology ,Toll-Like Receptor 4 ,TLR2 ,MALP-2 ,030104 developmental biology ,Infectious Diseases ,Gene Expression Regulation ,TLR4 ,Female ,Signal transduction ,lcsh:RC581-607 ,Signal Transduction ,030215 immunology - Abstract
Recent data argue for a pro-inflammatory role of CAMP (cathelicidin antimicrobial peptide) in adipocytes and adipose tissue (AT) and for regulatory circuits involving TLRs. In order to investigate regulatory effects of TLR2 and TLR4, 3T3-L1 adipocytes were stimulated with TLR2 agonistic lipopeptide MALP-2 and with TLR4 agonist LPS in presence or absence of signal transduction inhibitors. CAMP gene expression was analysed by quantitative real-time PCR in adipocytes and in murine AT compartments and cellular subfractions. CAMP expression was higher in gonadal than in subcutaneous AT and there was a gender-specific effect with higher levels in males. Adipocytes had higher CAMP expression than the stroma-vascular cell (SVC) fraction. MALP-2 up-regulated CAMP expression significantly, mediated by STAT3 and PI3K and potentially (non-significant trend) by NF-κB and MAPK, but not by raf-activated MEK-1/-2. Moreover, LPS proved to act as a potent inducer of CAMP via NF-κB, PI3K and STAT3, whereas specific inhibition of MAPK and MEK-1/-2 had no effect. In conclusion, activation of TLR2 and TLR4 by classical ligands up-regulates adipocyte CAMP expression involving classical signal transduction elements. These might represent future drug targets for pharmacological modulation of CAMP expression in adipocytes, especially in the context of metabolic and infectious diseases.
- Published
- 2021
14. Serum Levels and Adipose Tissue Gene Expression of Cathelicidin Antimicrobial Peptide (CAMP) in Obesity and During Weight Loss
- Author
-
Marissa Patz, Alexandra Hochberg, Andreas Schäffler, Thomas Karrasch, and Andreas Schmid
- Subjects
0301 basic medicine ,Adult ,Male ,medicine.medical_specialty ,Cathelicidin antimicrobial peptide ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,bariatric surgery ,Clinical Biochemistry ,Adipokine ,Adipose tissue ,030209 endocrinology & metabolism ,Biology ,adipocyte ,Biochemistry ,Cohort Studies ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Endocrinology ,Downregulation and upregulation ,Cathelicidins ,Internal medicine ,Adipocyte ,Gene expression ,Weight Loss ,medicine ,Adipocytes ,Animals ,Humans ,Longitudinal Studies ,Obesity ,Innate immune system ,Endocrine Care ,Insulin ,Biochemistry (medical) ,General Medicine ,Metabolism ,Middle Aged ,adipose tissue ,Obesity, Morbid ,030104 developmental biology ,chemistry ,NIH 3T3 Cells ,diet ,Antimicrobial Cationic Peptides - Abstract
CAMP (Cathelicidin antimicrobial peptide) is synthesized and secreted by adipocytes and involved in adipose tissue (AT) innate immune response and host defense of subcutaneous AT against Gram positive bacteria. Data on the regulation of CAMP in obesity and during weight loss are scarce and reference values do not exist. Serum CAMP levels (ELISA) and AT gene expression levels (quantitative real time PCR) were investigated in two large and longitudinal (12 months) cohorts of severely obese patients undergoing either a low calorie diet (LCD; n=79) or bariatric surgery (BS; n=156). The impact of metabolic factors on CAMP expression in vitro was investigated in differentiated 3T3-L1 adipocytes. CAMP serum levels significantly increased after BS but not during LCD. Females had lower CAMP serum levels and lower gene expression levels in subcutaneous AT. CAMP was positively correlated to unfavorable metabolic factors/adipokines and negatively to favorable factors/adipokines. CAMP gene expression was higher in subcutaneous than in visceral AT but serum CAMP levels were not correlated to levels of AT gene expression. While certain bile acids upregulated CAMP expression in vitro, high glucose/insulin as well as GLP-1 had an inhibitory effect. There exist gender-specific and AT compartment-specific effects on the regulation of CAMP gene expression. Weight loss induced by BS (but not by LCD) upregulated CAMP serum levels suggesting the involvement of weight loss-independent mechanisms in CAMP regulation such as bile acids, incretins and metabolic factors. CAMP might represent an adipokine at the interface between metabolism and innate immune response.
- Published
- 2021
15. Meteorin-Like Protein (Metrnl) in Obesity, during Weight Loss and in Adipocyte Differentiation
- Author
-
Schmid, Andreas, Karrasch, Thomas, and Schäffler, Andreas
- Subjects
meteorin-like protein ,obesity ,low calorie diet ,adipokine ,bariatric surgery ,Medicine ,adipocyte ,fatty acids ,Article ,Metrnl ,adipose tissue - Abstract
Meteorin-like protein (Metrnl) is an adipo-myokine with pleiotropic effects in adipose tissue (AT). Its systemic regulation in obesity and under weight loss is unclear. Circulating Metrnl concentrations were analyzed by ELISA in severely obese patients undergoing bariatric surgery (BS) or low calorie diet (LCD). Metrnl mRNA expression was analyzed in human and murine tissues and cell lines by quantitative real-time PCR. About 312 morbidly obese individuals underwent BS (n = 181, BMI 53.4 + 6.8 kg/m2) or LCD (n = 131, BMI 43.5 + 6.7 kg/m2). Serum samples were obtained at baseline and 3, 6, and 12 months after intervention. AT specimen from subcutaneous and visceral adipose tissue were resected during BS. Serum Metrnl levels were lower in type 2 diabetic patients and negatively correlated with HbA1c. In BS and LCD patients, Metrnl concentrations significantly increased after 3 months and returned to baseline levels after 12 months. There was no gender-specific effect. Metrnl mRNA expression did not differ between visceral and subcutaneous AT in n = 130 patients. In contrast, Metrnl gene expression in mice was highest in intra-abdominal AT followed by subcutaneous, peri-renal, and brown AT. In the murine 3T3-L1 cell line, Metrnl expression was high in pre-adipocytes and mature adipocytes with a transient downregulation during adipocyte differentiation. Metrnl expression remained unaffected upon treatment with glucose, insulin, fatty acids, bile acids, and incretins. Polyunsaturated omega-3 and omega-6 fatty acids downregulated Metrnl expression. Systemic Metrnl is transiently upregulated during massive weight loss and gene expression in adipocytes is differentially regulated.
- Published
- 2021
16. Toll-like Receptor 7 (TLR7) Is Expressed in Adipocytes and the Pharmacological TLR7 Agonist Imiquimod and Adipocyte-Derived Cell-Free Nucleic Acids (cfDNA) Regulate Adipocyte Function.
- Author
-
Thomalla, Miriam, Schmid, Andreas, Hehner, Julia, Koehler, Sebastian, Neumann, Elena, Müller-Ladner, Ulf, Schäffler, Andreas, and Karrasch, Thomas
- Subjects
NUCLEIC acids ,TOLL-like receptors ,CELL-free DNA ,PATTERN perception receptors ,GLUCOSE transporters ,ADIPOGENESIS ,ADIPOKINES ,RESISTIN - Abstract
Endosome-localized Toll-like receptors (TLRs) 3 and 9 are expressed and functionally active in adipocytes. The functionality and role of TLR7 in adipocyte biology and innate immunity of adipose tissue (AT) is poorly characterized. We analyzed TLR7 mRNA and protein expression in murine 3T3-L1 and primary adipocytes, in co-cultures of 3T3-L1 adipocytes with murine J774A.1 monocytes and in human AT. The effects of TLR7 agonists imiquimod (IMQ) and cell-free nucleic acids (cfDNA) on adipokine concentration in cell-culture supernatants and gene expression profile were investigated. We found that TLR7 expression is strongly induced during adipocyte differentiation. TLR7 gene expression in adipocytes and AT stroma-vascular cells (SVC) seems to be independent of TLR9. IMQ downregulates resistin concentration in adipocyte cell-culture supernatants and modulates gene expression of glucose transporter Glut4. Adipocyte-derived cfDNA reduces adiponectin and resistin in cell-culture supernatants and potentially inhibits Glut4 gene expression. The responsiveness of 3T3-L1 adipocytes to imiquimod is preserved in co-culture with J774A.1 monocytes. Obesity-related, adipocyte-derived cfDNA engages adipocytic pattern recognition receptors (PRRs), modulating AT immune and metabolic homeostasis during adipose inflammation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
17. The adipokine C1q/TNF-related protein-3 (CTRP-3) inhibits Toll-like receptor (TLR)-induced expression of Cathelicidin antimicrobial peptide (CAMP) in adipocytes
- Author
-
Alexandra Höpfinger, Andreas Schmid, Andreas Schäffler, and Thomas Karrasch
- Subjects
Lipopolysaccharides ,Male ,Immunology ,Adipokine ,Adipose tissue ,Biology ,Models, Biological ,Biochemistry ,Mice ,chemistry.chemical_compound ,Adipokines ,3T3-L1 Cells ,Adipocyte ,Adipocytes ,Animals ,Immunology and Allergy ,Receptor ,Molecular Biology ,Mice, Knockout ,Toll-like receptor ,Toll-Like Receptors ,Hematology ,Systemic Inflammatory Response Syndrome ,Cell biology ,Mice, Inbred C57BL ,Disease Models, Animal ,TLR2 ,Adipose Tissue ,Gene Expression Regulation ,chemistry ,TLR3 ,TLR4 ,Transcriptome ,Antimicrobial Peptides - Abstract
Background and aim CAMP (Cathelicidin antimicrobial peptide) expression in adipocytes is regulated by Toll-like receptor (TLR) agonists. Secreted adipokines such as CTRP-3 have been suggested to participate in innate immune signaling in adipose tissue (AT). This study investigates whether TLR-induced CAMP expression in adipocytes is antagonized by CTRP-3. Methods 3T3-L1 adipocytes were co-stimulated with TLR agonists (LPS, MALP-2, Pam3CSK4, pI:C) and recombinant CTRP-3. In a SIRS model, C57BL/6 wild-type mice were intraperitoneally (ip) injected with recombinant CTRP-3 prior to LPS. CAMP expression was analyzed by real-time PCR in AT of wild-type mice and in AT and primary adipocytes from transgenic mice lacking adipocyte CTRP-3 expression. Comparative transcriptome analysis by RNA seq. was applied in CTRP-3 KO adipocytes. Results In vitro, CTRP-3 antagonized TLR4- and TLR1/2-induced CAMP expression in adipocytes whereas TLR3- and TLR2/6-mediated induction of CAMP was not affected. in vivo, application of exogenous CTRP-3 dose-dependently antagonized LPS-induced CAMP expression in intra-abdominal AT. CAMP expression in total AT and in primary adipocytes of subcutaneous and intra-abdominal AT did not differ between wild-type mice and transgenic mice lacking adipocyte CTRP-3 expression. Conclusions The study suggests a hypothetical role of CAMP in host defense not only against Gram-positive bacteria sensed by TLR1/2 and TLR2/6 but also against Gram-negative bacteria sensed by TLR4 and potentially against viruses sensed by TLR3. The machinery of TLR-mediated pro-inflammatory activation of the CAMP gene in adipocytes seems to be partly modulated by secreted adipokines belonging to the growing family of C1q/TNF-related proteins such as CTRP-3.
- Published
- 2021
18. Frequency and significance of pro12Ala and Pro115Gln polymorphism in gene for peroxisome proliferation-activated receptor-γ2 regarding metabolic parameters in a caucasian cohortregarding metabolic parameters in a caucasian cohort
- Author
-
Schäffler, Andreas, Barth, Nicole, Schmitz, Gerd, Ziets, Bettina, Palitzsch, Klaus-Dieter, and Schölmerich, Jürgen
- Published
- 2001
- Full Text
- View/download PDF
19. CTRP-3 is permeable to the blood-brain barrier and is not regulated by glucose or lipidsin vivo
- Author
-
Andreas Schäffler, Thomas Karrasch, Martin Berghoff, Alexandra Hochberg, and Andreas Schmid
- Subjects
Adult ,Male ,0301 basic medicine ,medicine.medical_specialty ,Cell Membrane Permeability ,Adolescent ,Clinical Biochemistry ,Adipokine ,Adipose tissue ,030209 endocrinology & metabolism ,Stimulation ,Biology ,Blood–brain barrier ,Biochemistry ,Cohort Studies ,Mice ,Young Adult ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Cerebrospinal fluid ,3T3-L1 Cells ,Adipocyte ,Internal medicine ,Adipocytes ,medicine ,Animals ,Humans ,Glucose tolerance test ,medicine.diagnostic_test ,General Medicine ,Middle Aged ,Lipids ,Glucose ,030104 developmental biology ,medicine.anatomical_structure ,Endocrinology ,Postprandial ,Gene Expression Regulation ,chemistry ,Blood-Brain Barrier ,Case-Control Studies ,Tumor Necrosis Factors ,Female ,Biomarkers - Abstract
Background C1q/TNF-related protein-3 (CTRP-3) represents a novel anti-inflammatory and anti-diabetic adipokine secreted by adipose tissue. The physiological and postprandial regulation of CTRP-3 remains obscure and it is not known whether CTRP-3 is permeable to the brain Aim The postprandial regulation of CTRP-3 during an oral glucose tolerance test (n=100) and an oral lipid tolerance test (n=100) in humans was investigated. Moreover, CTRP-3 concentrations were measured in paired serum and cerebrospinal fluid (CSF) samples of patients (n=270) undergoing neurological evaluation. The expression of CTRP-3 mRNA was investigated in adipocytes upon stimulation with glucose, sex hormones and a broad panel of fatty acids Material and methods Serum and CSF CTRP-3 concentrations were measured by ELISA. 3T3-L1 adipocytes were used for stimulation experiments. CTRP-3 mRNA expression was quantified by using real-time PCR analysis Results CTRP-3 is present in human cerebrospinal fluid with a mean CSF/serum ratio of 110 + 64 x 10-3. CTRP-3 is not regulated postprandially by carbohydrates or lipids in the healthy state. Females have slightly higher levels of CTRP-3 when compared to males. A significant and positive correlation of CTRP-3 to LDL cholesterol serum levels is reproducible in several cohorts and deserves further mechanistic investigation. Whereas glucose concentrations do not influence CTRP-3 mRNA expression in 3T3-L1 adipocytes in vitro, fatty acids differentially modulate CTRP-3 expression Conclusions The novel adipokine CTRP-3 is detectable in human cerebrospinal fluid (proof of principle). Due to its blood-brain-barrier permeability, CTRP-3 represents a novel putative candidate for a physiological regulator molecule affecting central nervous functions. This article is protected by copyright. All rights reserved.
- Published
- 2017
20. Innate Immunity of Adipose Tissue in Rodent Models of Local and SystemicStaphylococcus aureusInfection
- Author
-
Miriam Thomalla, Thomas Karrasch, Andreas Schmid, Jutta Schlegel, Bernd Salzberger, Frank Hanses, and Andreas Schäffler
- Subjects
0301 basic medicine ,Innate immune system ,Article Subject ,Adipose tissue macrophages ,Immunology ,Adipose tissue ,Cell Biology ,Biology ,Systemic inflammation ,medicine.disease_cause ,Proinflammatory cytokine ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,TLR2 ,030104 developmental biology ,chemistry ,Staphylococcus aureus ,Adipocyte ,lcsh:Pathology ,medicine ,medicine.symptom ,lcsh:RB1-214 - Abstract
Background. The role of adipose tissue in systemic inflammation during bacterial infection is unclear. Effects ofStaphylococcus aureusinfection on adipocytes in rodent models of experimental endocarditis and peritonitis, the impact ofS. aureusinfection on gene expression in epididymal and subcutaneous adipose tissue, and effects ofS. aureusinfection on the toll-like receptor-2- (TLR2-) cathelicidin pathway in vivo and in vitro were investigated.Material and methods.The rat model of catheter-inducedS. aureusendocarditis and the mouse model ofS. aureus-induced peritonitis were used for infection experiments, gene expression profiling in adipose tissue, and measurement of cytokines. 3T3-L1 adipocytes were analyzed for expression of the TLR2-cathelicidin pathway.Results. Upon systemic bacterial infection byS. aureus, there is a shift from anti- to proinflammatory cytokines in serum and in adipose tissue gene expression. The TLR2-cathelicidin pathway is increasingly expressed during adipocyte differentiation in vitro and is induced upon stimulation by synthetic lipopeptides.Conclusions. Systemic infection by Gram-positive bacteria induces proinflammatory transformation of adipose tissue sites distinct from infection sites, documented on the levels of gene expression and secreted mediators. The TLR2-cathelicidine pathway is expressed and highly inducible in adipocytes in vitro. Lipopeptides are important immune-modulators of adipocytes in both gene expression and protein secretion.
- Published
- 2017
21. Role of progranulin in adipose tissue innate immunity
- Author
-
Andreas Schmid, Alexandra Hochberg, Thomas Karrasch, Jonas Gehl, Frank Hanses, Andreas Schäffler, Anja Franziska Kreiß, Miriam Thomalla, and Marissa Patz
- Subjects
0301 basic medicine ,Lipopolysaccharides ,Male ,Adipose tissue ,Biochemistry ,chemistry.chemical_compound ,Mice ,Phosphatidylinositol 3-Kinases ,0302 clinical medicine ,Progranulins ,Adipocyte ,Gene expression ,Adipocytes ,Immunology and Allergy ,Insulin ,Testosterone ,Phosphoinositide-3 Kinase Inhibitors ,Toll-like receptor ,Adipogenesis ,Estradiol ,Fatty Acids ,Toll-Like Receptors ,NF-kappa B ,Hematology ,Staphylococcal Infections ,Adipose Tissue ,030220 oncology & carcinogenesis ,Tumor necrosis factor alpha ,Female ,medicine.symptom ,medicine.medical_specialty ,Immunology ,Adipokine ,Inflammation ,Biology ,Peritonitis ,Bile Acids and Salts ,03 medical and health sciences ,Internal medicine ,mental disorders ,medicine ,Animals ,Molecular Biology ,Interleukin-6 ,Tumor Necrosis Factor-alpha ,Immunity, Innate ,Mice, Inbred C57BL ,TLR2 ,030104 developmental biology ,Endocrinology ,Glucose ,chemistry ,Gene Expression Regulation - Abstract
Regulation of progranulin in adipocytes and its role in inflammation is poorly understood. Aim: (i) to investigate regulation of progranulin in adipocyte differentiation and adipose tissue compartments, (ii) to address progranulin expression in two murine (C57BL/6) models of inflammation. Results: Progranulin expression was induced during adipocyte differentiation. Neither estradiol nor testosterone or metabolic stimuli such as glucose and insulin modified progranulin synthesis. Fatty acids, bile acids and incretins GLP-1 and GIP-1 exerted potent and differential effects on progranulin secretion. LPS, TNF and IL6 significantly increased progranulin secretion. TLR9 agonists decreased and TLR1/2, TLR3, TLR5, and TLR2/6 ligands increased progranulin expression. TLR3-mediated progranulin induction was abrogated by inhibitors of NF-κB and PI3K pathways. Progranulin expression between murine epididymal and subcutaneous adipose tissue did not differ in total adipose tissue, in isolated adipocytes or in the stromal-vascular cell fraction (SVC). However, SVC expressed significantly higher levels of progranulin than adipocytes at all sites. In adipocytes, female mice had significantly higher progranulin expression at all sites. An intra-peritoneal LPS challenge in mice did not affect adipose tissue progranulin expression, whereas peritoneal infection by S. aureus increased progranulin expression after 24 h. Conclusions: There are relevant sex-, site- and cell-specific effects on progranulin gene expression that is induced during adipocyte differentiation and modulated by various inflammatory and metabolic factors. Most importantly, ligands for TLR1/2 and TLR2/6 (recognizing S. aureus) in vitro and infection by S. aureus in vivo induce progranulin expression suggesting a role of adipocytes in protection against infection by gram-positive bacteria.
- Published
- 2019
22. Evidence of an anti-inflammatory toll-like receptor 9 (TLR 9) pathway in adipocytes
- Author
-
Elena Neumann, Thomas Karrasch, Petra Ina Pfefferle, Miriam Thomalla, Ulf Müller-Ladner, Andreas Schäffler, and Andreas Schmid
- Subjects
0301 basic medicine ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Adipose tissue ,Adipokine ,Gene Expression ,chemical and pharmacologic phenomena ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Endocrinology ,immune system diseases ,Internal medicine ,Adipocyte ,3T3-L1 Cells ,parasitic diseases ,medicine ,Adipocytes ,Animals ,Humans ,Adiponectin secretion ,Resistin ,Obesity ,Receptor ,Cells, Cultured ,Inflammation ,Gene knockdown ,Adiponectin ,Chemistry ,hemic and immune systems ,Cell Differentiation ,030104 developmental biology ,Adipose Tissue ,Oligodeoxyribonucleotides ,030220 oncology & carcinogenesis ,Toll-Like Receptor 9 ,RNA Interference ,Signal Transduction - Abstract
Adipocytes express various pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs) and actively participate in anti-bacterial and anti-viral host defence. Obesity is associated with adipose tissue PRR expression. The potential role of Toll-like receptor 9 (TLR9) in adipocytes has not yet been investigated. Here, we evaluated TLR9 expression during adipocyte differentiation (AD) of 3T3-L1 adipocytes, in primary murine adipocytes and in different murine and human adipose tissue depots by real-time PCR, immunocytochemistry and immunohistochemistry. TLR9 expression was inhibited using specific siRNA-mediated knockdown, and TLR9 signaling was induced using specific class A, B and C agonistic CpG-oligodeoxynucleotide (ODN) treatment vs ODN controls in 3T3-L1 adipocytes and in primary murine adipocytes from Tlr9wt/wt vs Tlr9−/− mice. We found that TLR9 gene expression is induced during AD and that TLR9 protein is expressed in murine gonadal and human visceral adipocytes. AD depends on intact TLR9 expression. Tlr9−/− mice demonstrate significantly reduced adiponectin serum levels, while siRNA-mediated TLR9 knockdown led to reduced adiponectin mRNA expression in adipocytes. TLR9 ligands (CpG-ODNs) inhibit pro-inflammatory resistin secretion in mature 3T3-L1 adipocytes. Tlr9−/− as compared to Tlr9wt/wt adipocytes exhibit increased resistin and MCP1 secretion and reduced adiponectin secretion into cell culture supernatants, while TLR9 ligands (ODNs) show differential effects in Tlr9−/− vs Tlr9wt/wt primary murine adipocytes. TLR9 expression is significantly increased in visceral compared to subcutaneous adipose tissue depots in non-diabetic obese patients and correlates with systemic resistin levels in a compartment-specific manner. Thus, adipocytic TLR9 is a putative, new protective factor during (obesity-associated) adipose tissue inflammation.
- Published
- 2018
23. Serum Levels and Adipose Tissue Gene Expression of Cathelicidin Antimicrobial Peptide (CAMP) in Obesity and During Weight Loss.
- Author
-
Hochberg, Alexandra, Patz, Marissa, Karrasch, Thomas, Schäffler, Andreas, and Schmid, Andreas
- Abstract
CAMP (Cathelicidin antimicrobial peptide) is synthesized and secreted by adipocytes and involved in adipose tissue (AT) innate immune response and host defense of subcutaneous AT against Gram positive bacteria. Data on the regulation of CAMP in obesity and during weight loss are scarce and reference values do not exist. Serum CAMP levels (ELISA) and AT gene expression levels (quantitative real time PCR) were investigated in two large and longitudinal (12 months) cohorts of severely obese patients undergoing either a low calorie diet (LCD; n=79) or bariatric surgery (BS; n=156). The impact of metabolic factors on CAMP expression in vitro was investigated in differentiated 3T3-L1 adipocytes. CAMP serum levels significantly increased after BS but not during LCD. Females had lower CAMP serum levels and lower gene expression levels in subcutaneous AT. CAMP was positively correlated to unfavorable metabolic factors/adipokines and negatively to favorable factors/adipokines. CAMP gene expression was higher in subcutaneous than in visceral AT but serum CAMP levels were not correlated to levels of AT gene expression. While certain bile acids upregulated CAMP expression in vitro, high glucose/insulin as well as GLP-1 had an inhibitory effect. There exist gender-specific and AT compartment-specific effects on the regulation of CAMP gene expression. Weight loss induced by BS (but not by LCD) upregulated CAMP serum levels suggesting the involvement of weight loss-independent mechanisms in CAMP regulation such as bile acids, incretins and metabolic factors. CAMP might represent an adipokine at the interface between metabolism and innate immune response. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
24. Evidence of functional bile acid signaling pathways in adipocytes
- Author
-
Thomas Karrasch, Jutta Schlegel, Miriam Thomalla, Andreas Schmid, and Andreas Schäffler
- Subjects
0301 basic medicine ,Adult ,Lipopolysaccharides ,Male ,medicine.medical_specialty ,medicine.drug_class ,Lipolysis ,Adipocytes, White ,Glycocholic acid ,Adipose tissue ,Receptors, Cytoplasmic and Nuclear ,030209 endocrinology & metabolism ,Biochemistry ,Receptors, G-Protein-Coupled ,Bile Acids and Salts ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Endocrinology ,Adipokines ,Internal medicine ,Adipocyte ,3T3-L1 Cells ,medicine ,Animals ,Humans ,Receptor, Fibroblast Growth Factor, Type 1 ,Molecular Biology ,ATP Binding Cassette Transporter, Subfamily B, Member 11 ,Cells, Cultured ,Adiponectin ,Bile acid ,Chemistry ,Deoxycholic acid ,Cell Differentiation ,G protein-coupled bile acid receptor ,030104 developmental biology ,Gene Expression Regulation ,Female - Abstract
Background and aim Bile acids (BA) are increasingly recognized as pleiotropic and hormone-like signaling molecules with metabolic and endocrine functions. However, the role of BA in white adipocyte physiology remains somewhat obscure. It was the aim to investigate the BA receptors (FXR, TGR5) and FGFR1 (Fibroblast growth factor receptor 1) as well as Bsep (bile salt export pump) in white adipocytes and in murine and human adipose tissue (AT) and to investigate effects of different BA species in adipocyte physiology. Patients, material and methods Receptor mRNA expression was quantified by real-time PCR in mice, humans and during 3T3-L1 pre-adipocyte differentiation. Adipokines were measured by ELISA upon stimulation by several BA. Effects of BA on TNF- and LPS-induced MCP-1 secretion and lipolysis were analyzed. TNF-induced lipolysis was investigated by glycerol assay. Results The present data provide for the first time a detailed expression profile of FXR, TGR5, FGFR1, and Bsep during adipocyte differentiation and in murine and human AT. FGFR1 expression is upregulated in adipose tissue of LPS-injected animals. Several BA regulate secretion of adipokines such as adiponectin and resistin differentially. Importantly, TNF- and LPS-induced MCP-1 release from adipocytes as well as TNF-induced lipolysis can be antagonized by cholic acid (CA) and deoxycholic acid (DCA). Conclusions The present data provide evidence of functional BA signaling pathways in adipocytes and argue for certain MCP-1 related anti-inflammatory effects of BA in TNF- and LPS-induced inflammation, whereas pro-inflammatory resistin is induced by CA and glycocholic acid (GCA). Systemic bile acids might represent a hormonal network regulating white adipocyte physiology including lipolysis.
- Published
- 2018
25. Regulation of natriuretic peptides postprandially in vivo and of their receptors in adipocytes by fatty acids in vitro
- Author
-
Efthymia Arapogianni, Thomas Karrasch, Andreas Schmid, Jens Albrecht, Judith Brock, Maria Koukou, and Andreas Schäffler
- Subjects
Adult ,Male ,medicine.medical_specialty ,medicine.drug_class ,Adipose tissue ,030209 endocrinology & metabolism ,Stimulation ,030204 cardiovascular system & hematology ,Biochemistry ,Cohort Studies ,03 medical and health sciences ,chemistry.chemical_compound ,Mice ,0302 clinical medicine ,Endocrinology ,Adipocyte ,Internal medicine ,3T3-L1 Cells ,medicine ,Natriuretic peptide ,Adipocytes ,Lipolysis ,Animals ,Humans ,Insulin ,RNA, Messenger ,Receptor ,Natriuretic Peptides ,Molecular Biology ,Glucose tolerance test ,medicine.diagnostic_test ,Fatty Acids ,Cell Differentiation ,Glucose Tolerance Test ,Postprandial Period ,Mice, Inbred C57BL ,Postprandial ,Glucose ,chemistry ,Adipose Tissue ,Gene Expression Regulation ,Female ,Receptors, Atrial Natriuretic Factor - Abstract
Background and aim Natriuretic peptides (NPs) and their receptors gain attention regarding adipocyte function. It was the aim to investigate the expression of natriuretic peptide receptors NPR-A, NPR-B and NPR-C during adipocyte differentiation (AD), upon stimulation with fatty acids (FA), and in murine and human adipose tissue depots (AT) of patients undergoing bariatric surgery (n = 44). Patients, material and methods The postprandial regulation of NT-proANP and NT-proBNP levels was measured by ELISA and was studied in two cohorts of healthy individuals undergoing an oral glucose tolerance test (OGTT) (n = 100) and an oral lipid tolerance test (OLTT) (n = 100). Adipocyte mRNA expression was investigated by quantitative real-time PCR. Results During AD, an early expression pattern could be described for NPR-C, a bimodal expression for NPR-B and a late expression pattern for NPR-A. NPR-A and NPR-B expression was high in epididymal and subcutaneous AT but low in peri-renal AT of mice. NPR-C showed a differential expression profile. FA stimulation caused a significant and differential regulation of NPRs in adipocytes. Serum NT-proANP and NT-proBNP concentrations did not change during OGTT, whereas NT-proANP significantly declined during OLTT. Basal NT-proANP and NT-proBNP concentrations were positively correlated with each other and with FGF-19 and FGF-21 levels. Conclusion Adipocytes and AT show a characteristic expression of NPRs. FA are able to regulate NPR expression differentially. There is a postprandial and negative regulation of serum NT-proANP concentrations after OLTT and of NPR-A after FA stimulation. Both effects could represent a novel hypothetical negative feedback mechanism on adipocyte lipolysis.
- Published
- 2017
26. Regulation of CAMP (cathelicidin antimicrobial peptide) expression in adipocytes by TLR 2 and 4.
- Author
-
Höpfinger, Alexandra, Karrasch, Thomas, Schäffler, Andreas, and Schmid, Andreas
- Subjects
FAT cells ,CYCLIC-AMP-dependent protein kinase ,ADIPOSE tissues ,CELLULAR signal transduction ,PHOSPHATIDYLINOSITOL 3-kinases ,COMMUNICABLE diseases - Abstract
Recent data argue for a pro-inflammatory role of CAMP (cathelicidin antimicrobial peptide) in adipocytes and adipose tissue (AT) and for regulatory circuits involving TLRs. In order to investigate regulatory effects of TLR2 and TLR4, 3T3-L1 adipocytes were stimulated with TLR2 agonistic lipopeptide MALP-2 and with TLR4 agonist LPS in presence or absence of signal transduction inhibitors. CAMP gene expression was analysed by quantitative real-time PCR in adipocytes and in murine AT compartments and cellular subfractions. CAMP expression was higher in gonadal than in subcutaneous AT and there was a gender-specific effect with higher levels in males. Adipocytes had higher CAMP expression than the stroma-vascular cell (SVC) fraction. MALP-2 up-regulated CAMP expression significantly, mediated by STAT3 and PI3K and potentially (non-significant trend) by NF-κB and MAPK, but not by raf-activated MEK-1/-2. Moreover, LPS proved to act as a potent inducer of CAMP via NF-κB, PI3K and STAT3, whereas specific inhibition of MAPK and MEK-1/-2 had no effect. In conclusion, activation of TLR2 and TLR4 by classical ligands up-regulates adipocyte CAMP expression involving classical signal transduction elements. These might represent future drug targets for pharmacological modulation of CAMP expression in adipocytes, especially in the context of metabolic and infectious diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
27. Intracellular Survival of Staphylococcus aureus in Adipocyte-Like Differentiated 3T3-L1 Cells Is Glucose Dependent and Alters Cytokine, Chemokine, and Adipokine Secretion
- Author
-
Andrea Kopp, Margarita Bala, Werner Falk, Bernd Salzberger, Andreas Schäffler, Frank Hanses, and Christa Buechler
- Subjects
Staphylococcus aureus ,medicine.medical_specialty ,medicine.medical_treatment ,Adipose tissue ,Adipokine ,Proinflammatory cytokine ,Mice ,chemistry.chemical_compound ,Endocrinology ,Adipokines ,3T3-L1 Cells ,Internal medicine ,Adipocyte ,Lipid droplet ,medicine ,Animals ,Insulin ,Adiponectin ,biology ,Cell Differentiation ,Insulin receptor ,Glucose ,chemistry ,biology.protein ,Cytokines ,Chemokines - Abstract
Although obesity and type 2 diabetes mellitus are associated with Gram-positive infections and a worse clinical outcome, it is unknown whether adipocytes can be infected by Gram-positive bacteria. Adipocyte-like differentiated 3T3-L1 cells and Staphylococcus aureus were used for infection experiments under normoglycemic (100 mg/dl) and hyperglycemic (450 mg/dl) conditions in the presence/absence of insulin (1 μm). Intracellular presence and survival of S. aureus was investigated quantitatively. Supernatant cytokines, chemokines, and adipokines were measured by ELISA. Lipid metabolism and cellular morphology of infected adipocytes were investigated by different techniques. The present study provides the proof of principle that adipocyte-like cells can be infected by S. aureus dose dependently for up to 5 d. Importantly, low bacterial inocula did not affect cell viability. Intracellular survival of S. aureus was glucose dependent but not insulin dependent, and insulin receptor expression and insulin receptor signaling were not altered. Infection increased macrophage chemoattractant protein-1, visfatin, and IL-6 secretion, whereas resistin and adiponectin were decreased. Infected adipocytes had higher intracellular triacylglycerol concentrations and larger lipid droplets because of a decreased lipolysis. Taken together, infection of adipocytes by S. aureus is glucose dependent, inhibits cellular lipolysis, and affects the secretion of immunomodulating adipokines differentially. Because cell viability is not affected during infection, adipose tissue might function as a host for chronic infection by bacteria-causing metabolic, proinflammatory, and prodiabetic disturbances.
- Published
- 2011
28. Sterol Regulatory Element-Binding Protein 2 (SREBP2) Activation after Excess Triglyceride Storage Induces Chemerin in Hypertrophic Adipocytes
- Author
-
Josef Wanninger, Sandra Schmidhofer, Sabrina Bauer, Nicole Zimara, Charalampos Aslanidis, Christa Buechler, Christoph Dorn, Claus Hellerbrand, Markus Neumeier, Andreas Schäffler, and Johanna Weigert
- Subjects
medicine.medical_specialty ,Adipose tissue ,Adipokine ,CMKLR1 ,Receptors, G-Protein-Coupled ,Mice ,chemistry.chemical_compound ,Endocrinology ,3T3-L1 Cells ,Adipocyte ,Internal medicine ,Adipocytes ,medicine ,Animals ,Chemerin ,Triglycerides ,Chemotactic Factors ,biology ,Interleukin-6 ,Reverse Transcriptase Polymerase Chain Reaction ,Tumor Necrosis Factor-alpha ,Sterol regulatory element-binding protein ,Mice, Inbred C57BL ,Gene Expression Regulation ,chemistry ,biology.protein ,Intercellular Signaling Peptides and Proteins ,Female ,Receptors, Chemokine ,Sterol regulatory element-binding protein 2 ,Chemokines ,Adipocyte hypertrophy ,Sterol Regulatory Element Binding Protein 2 - Abstract
Chemerin is an adipokine whose systemic concentration and adipose tissue expression is increased in obesity. Chemerin is highly abundant in adipocytes, yet the molecular mechanisms mediating its further induction in obesity have not been clarified. Adipocyte hypertrophy contributes to dysregulated adipokine synthesis, and we hypothesized that excess loading with free fatty acids (FFA) stimulates chemerin synthesis. Chemerin was expressed in mature adipocytes, and differentiation of 3T3-L1 cells in the presence of FFA further increased its level. TNF and IL-6 were induced by FFA, but concentrations were too low to up-regulate chemerin. Sterol regulatory element-binding protein 2 (SREBP2) was activated in these cells, indicative for cholesterol shortage. Suppression of cholesterol synthesis by lovastatin led to activation of SREBP2 and increased chemerin, and supplementation with mevalonate reversed this effect. Knockdown of SREBP2 reduced basal and FFA-induced chemerin. EMSA confirmed binding of 3T3-L1 adipocyte nuclear proteins to a SREBP site in the chemerin promotor. SREBP2 was activated and chemerin was induced in adipose tissue of mice fed a high-fat diet, and higher systemic levels seem to be derived from adipocytes. Lipopolysaccharide-mediated elevation of chemerin was similarly effective as induction by FFA, indicating that both mechanisms are equally important. Chemokine-like receptor 1 was not altered by the incubations mentioned above, and higher expression in fat of mice fed a high-fat diet may reflect increased number of adipose tissue-resident macrophages in obesity. In conclusion, the current data show that adipocyte hypertrophy and chronic inflammation are equally important in inducing chemerin synthesis.
- Published
- 2011
29. Serum Galectin-3 Is Elevated in Obesity and Negatively Correlates with Glycosylated Hemoglobin in Type 2 Diabetes
- Author
-
Marcus N. Scherer, Josef Wanninger, Stefan Farkas, Johanna Weigert, Markus Neumeier, Jürgen Schölmerich, Andreas Schäffler, Charalampos Aslanidis, Christa Buechler, Andreas A. Schnitzbauer, and Sabrina Bauer
- Subjects
Adult ,Leptin ,Male ,medicine.medical_specialty ,Cirrhosis ,Galectin 3 ,Endocrinology, Diabetes and Metabolism ,Blotting, Western ,Clinical Biochemistry ,Adipokine ,Adipose tissue ,Enzyme-Linked Immunosorbent Assay ,Type 2 diabetes ,Intra-Abdominal Fat ,Systemic inflammation ,Biochemistry ,Statistics, Nonparametric ,Body Mass Index ,Mice ,chemistry.chemical_compound ,Endocrinology ,Diabetes mellitus ,Adipocyte ,Internal medicine ,Adipocytes ,otorhinolaryngologic diseases ,medicine ,Animals ,Humans ,Resistin ,Obesity ,Cells, Cultured ,Aged ,Glycated Hemoglobin ,business.industry ,Biochemistry (medical) ,Middle Aged ,medicine.disease ,Metformin ,stomatognathic diseases ,Diabetes Mellitus, Type 2 ,chemistry ,Female ,medicine.symptom ,business - Abstract
Adipocytes synthesize galectin-3 whose deficiency protects from inflammation associated with metabolic diseases. We aimed to study circulating galectin-3 in obesity and type 2 diabetes (T2D).Galectin-3 was measured by ELISA in the serum of male normal-weight and overweight controls and T2D patients and in T2D patients of both sexes. Because visceral fat contributes to systemic inflammation, galectin-3 was analyzed in paired samples of human and rodent sc and visceral adipose tissue. Visceral adipose tissue adipokines are released to the portal vein, and galectin-3 was analyzed in portal, hepatic, and systemic venous serum (PVS, HVS, and SVS, respectively) of patients with liver cirrhosis and in patients who underwent surgery for nonhepatic diseases. The effect of metformin on adipocyte galectin-3 was analyzed by immunoblot.Circulating galectin-3 was similarly elevated in T2D and obesity compared with normal-weight individuals and revealed a body mass index-dependent positive correlation with leptin, resistin, IL-6, and age. In T2D patients, galectin-3 was increased in serum of patients with elevated C-reactive protein and negatively correlated with glycated hemoglobin. Metformin treatment was associated with lower systemic galectin-3. Reduced galectin-3 in metformin-incubated human adipocytes indicated that low galectin-3 may be a direct effect of this drug. Galectin-3 was higher in PVS compared with HVS and SVS, suggesting that the splanchnic region is a major site of galectin-3 synthesis. Low galectin-3 in HVS compared with PVS demonstrated hepatic removal.Systemic galectin-3 is elevated in obesity and negatively correlates with glycated hemoglobin in T2D patients, pointing to a modifying function of galectin-3 in human metabolic diseases.
- Published
- 2010
30. Innate Immunity and Adipocyte Function: Ligand-specific Activation of Multiple Toll-like Receptors Modulates Cytokine, Adipokine, and Chemokine Secretion in Adipocytes
- Author
-
J. Schölmerich, Charalampos Aslanidis, M. Neumeier, Andreas Schäffler, Andrea Kopp, Johanna Weigert, and Christa Buechler
- Subjects
Lipopolysaccharides ,Chemokine ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Subcutaneous Fat ,Medicine (miscellaneous) ,Adipose tissue ,Adipokine ,Intra-Abdominal Fat ,Ligands ,Cell Line ,Mice ,chemistry.chemical_compound ,Endocrinology ,Adipokines ,Adipocyte ,Internal medicine ,Adipocytes ,medicine ,Animals ,Humans ,Resistin ,Cells, Cultured ,Chemokine CCL2 ,Nutrition and Dietetics ,biology ,Interleukin-6 ,Chemistry ,Toll-Like Receptors ,NF-kappa B ,Immunity, Innate ,Toll-Like Receptor 4 ,TLR5 ,Adipogenesis ,Chemokine secretion ,biology.protein ,Cytokines ,Chemokines ,Corticosterone ,Signal Transduction - Abstract
The aim of this study was to analyze Toll-like receptor (TLR) expression in preadipocytes and mature adipocytes and to investigate whether TLR ligands influence the release of cytokines, chemokines, and adipokines. Murine 3T3-L1 preadipocytes and mature adipocytes were used for stimulation experiments. The effects of lipopolysaccharide (LPS), flagellin, Poly (U), Poly (I:C), macrophage-activating lipopeptide-2 (MALP2), Pam3Cys, and CpG on the release of interleukin-6 (IL-6), resistin, and monocyte chemoattractant protein-1 (MCP-1) were determined by enzyme-linked immunosorbent assay (ELISA). Nuclear translocation and promoter binding of NFkappaB were analyzed by electrophoretic mobility shift assays. TLR expression was investigated by reverse-transcriptase (RT-PCR). All TLRs except TLR5 and TRL7 are expressed in the stromal vascular cell (SVC) fraction and in mature adipocytes of different fat stores. Whereas basal and LPS-induced IL-6 release is higher in preadipocytes, basal and LPS-induced MCP-1 release is higher in mature adipocytes. Mature adipocytes respond to corticosterone regarding MCP-1 and resistin release. The ligands for TLRs influence IL-6, MCP-1, and resistin release differentially. Some of these ligands induce nuclear translocation and promoter binding of NFkappaB. Besides TLR5, that is not expressed in mature adipocytes, all TLR family members are involved. There exists a functional TRL pathway in adipocytes that connects innate immunity with adipocyte function. As a consequence, the role of the adipose tissue in both immunity and metabolism has to be investigated in future studies. The results of this approach will help to explain the metabolic changes such as insulin resistance observed during infection and the immunological phenomena such as macrophage infiltration of adipose tissue seen in obesity.
- Published
- 2009
31. The role of adiponectin in inflammatory gastrointestinal diseases
- Author
-
Jürgen Schölmerich and Andreas Schäffler
- Subjects
Male ,Gene isoform ,medicine.medical_specialty ,Adipose tissue ,Adipokine ,Inflammation ,Biology ,Hepatitis ,Mice ,chemistry.chemical_compound ,Internal medicine ,Adipocyte ,medicine ,Animals ,Humans ,Secretion ,Receptor ,Adiponectin ,Gastroenterology ,Gastroenteritis ,Endocrinology ,Pancreatitis ,chemistry ,Acute Disease ,Female ,medicine.symptom - Abstract
Adiponectin was discovered in 1995 by Phillip Scherer’s research group and described as a novel serum protein similar to C1q, being produced exclusively in adipocytes.1 Adiponectin represents an anti-inflammatory, anti-diabetic and anti-fibrotic adipokine that is highly abundant in human plasma. Adiponectin is induced during adipocyte differentiation and secreted from mature adipocytes into the blood stream where it circulates as homo-trimeric, hexameric, nonameric and higher molecular weight isoforms. Mutations in the gene encoding adiponectin result in an impaired multimer formation and cause lower levels of high-molecular weight isoforms in the plasma as well as a reduced abundance of all isoforms due to a disturbed secretion from the adipocyte.2 There are two receptors for adiponectin, AdipoR1 and AdipoR2, which are expressed in a wide variety of organs and cell types. The full-length and the truncated globular isoforms of adiponectin exhibit different receptor binding activities. Processes leading to a cleavage of the full-length protein and the exact mode of receptor interaction of different isoforms are only poorly understood. Adiponectin represents the only adipokine that is downregulated in obesity. Adiponectin exerts pleiotropic effects in several organs and its role in metabolism3 and in inflammation,4–7 in general, are reviewed elsewhere. Obesity can be regarded as a chronic and low-grade state of inflammation8 and the interpretation of the role of the adipose tissue has developed from a simple energy store to a highly active endocrine,9 inflammatory5 and immunological4 organ. In the context of obesity, the adipose tissue undergoes an inflammatory transformation10 and becomes infiltrated by significant amounts of macrophages.8 11 Since adiponectin is secreted by intra-abdominal adipose tissue and acts on monocytes in an anti-inflammatory way, it seems reasonable to review the role of adiponectin with respect to inflammatory gastrointestinal diseases, especially to those …
- Published
- 2009
32. Interfering Effects of Insulin, Growth Hormone and Glucose on Adipokine Secretion
- Author
-
Charalampos Aslanidis, Wölfing B, J. Schölmerich, Christa Buechler, Andreas Schäffler, and M. Neumeier
- Subjects
medicine.medical_specialty ,endocrine system diseases ,Endocrinology, Diabetes and Metabolism ,medicine.medical_treatment ,Blotting, Western ,Adipokine ,Biology ,Mice ,chemistry.chemical_compound ,Endocrinology ,Adipokines ,3T3-L1 Cells ,Adipocyte ,Internal medicine ,Adipocytes ,Internal Medicine ,Hyperinsulinemia ,medicine ,Animals ,Insulin ,Drug Interactions ,Resistin ,Adiponectin secretion ,Pancreatic hormone ,Adiponectin ,nutritional and metabolic diseases ,General Medicine ,Scavenger Receptors, Class B ,medicine.disease ,Glucose ,chemistry ,Growth Hormone ,hormones, hormone substitutes, and hormone antagonists - Abstract
INTRODUCTION: Cell culture media with high glucose concentration are normally used. Data on the secretion of the adipokines adiponectin and resistin from adipocytes in response to insulin and growth hormone (GH) both under normo- and hyperglycemic conditions are not available. It was the aim of the study to investigate the impact of standard metabolic conditions (normo-/hyperglycemia, normo-/hyperinsulinemia) and of GH on the secretion of adiponectin and resistin. MATERIAL AND METHODS: 3T3-L1 preadipocytes were differentiated into adipocytes and then incubated under normoglycemia (100 mg/dl), hyperglycemia (450 mg/dl), in combination with insulin (0, 0.2, 2.0 nM) and/or GH (1 nM). Adiponectin and resistin secretion was measured by ELISA. RESULTS: Insulin significantly stimulates adiponectin and resistin secretion under normo- and hyperglycemia. Hyperglycemia PER SE stimulates adiponectin and resistin secretion both in the absence and presence of low or high insulin concentrations. GH stimulates adiponectin secretion both under normoglycemic and hyperglycemic conditions. Whereas insulin does not modulate GH-induced adiponectin secretion under normoglycemia, insulin augments adiponectin release under hyperglycemia. GH stimulates resistin secretion only under normoglycemia, but not under hyperglycemic conditions. Since scavenger receptor B-I expression did not change, these effects are specific and not caused by a simple enhancement of adipocyte differentiation. DISCUSSION: Glucose, insulin and growth hormone have significant and interfering effects on the secretion of resistin and adiponectin. Several of the well-known in vivo phenomena such as diurnal variation or effects of re-feeding and weight-loss might be explained by direct effects of these hormones on adipocytes. Finally, when effects of hormones on adipocyte function are investigated, it is a prerequisite to take glucose levels of the cell culture media into account.
- Published
- 2007
33. Concise Review: Adipose Tissue-Derived Stromal Cells—Basic and Clinical Implications for Novel Cell-Based Therapies
- Author
-
Christa Büchler and Andreas Schäffler
- Subjects
Stromal cell ,Tissue Engineering ,Cellular differentiation ,Mesenchymal stem cell ,Cell ,Cell- and Tissue-Based Therapy ,Adipose tissue ,Cell Differentiation ,Cell Biology ,Anatomy ,Biology ,Cell biology ,Mesoderm ,Cell therapy ,chemistry.chemical_compound ,medicine.anatomical_structure ,Adipose Tissue ,Tissue engineering ,chemistry ,Adipocyte ,medicine ,Humans ,Molecular Medicine ,Stromal Cells ,Developmental Biology - Abstract
Compared with bone marrow-derived mesenchymal stem cells, adipose tissue-derived stromal cells (ADSC) do have an equal potential to differentiate into cells and tissues of mesodermal origin, such as adipocytes, cartilage, bone, and skeletal muscle. However, the easy and repeatable access to subcutaneous adipose tissue and the simple isolation procedures provide a clear advantage. Since extensive reviews focusing exclusively on ADSC are rare, it is the aim of this review to describe the preparation and isolation procedures for ADSC, to summarize the molecular characterization of ADSC, to describe the differentiation capacity of ADSC, and to discuss the mechanisms and future role of ADSC in cell therapy and tissue engineering. An initial effort has also been made to differentiate ADSC into hepatocytes, endocrine pancreatic cells, neurons, cardiomyocytes, hepatocytes, and endothelial/vascular cells. Whereas the lineage-specific differentiation into cells of mesodermal origin is well understood on a molecular basis, the molecular key events and transcription factors that initially allocate the ADSC to a lineage-specific differentiation are almost completely unknown. Decoding these molecular mechanisms is a prerequisite for developing novel cell therapies. Disclosure of potential conflicts of interest is found at the end of this article.
- Published
- 2007
34. Evidence of an anti-inflammatory toll-like receptor 9 (TLR 9) pathway in adipocytes.
- Author
-
Thomalla, Miriam, Schmid, Andreas, Neumann, Elena, Pfefferle, Petra Ina, Müller-Ladner, Ulf, Schäffler, Andreas, and Karrasch, Thomas
- Subjects
TOLL-like receptors ,PATTERN perception receptors ,ADIPOSE tissues ,FAT cells - Abstract
Adipocytes express various pattern recognition receptors (PRRs) such as Toll-like receptors (TLRs) and actively participate in anti-bacterial and anti-viral host defence. Obesity is associated with adipose tissue PRR expression. The potential role of Toll-like receptor 9 (TLR9) in adipocytes has not yet been investigated. Here, we evaluated TLR9 expression during adipocyte differentiation (AD) of 3T3-L1 adipocytes, in primary murine adipocytes and in different murine and human adipose tissue depots by real-time PCR, immunocytochemistry and immunohistochemistry. TLR9 expression was inhibited using specific siRNA-mediated knockdown, and TLR9 signaling was induced using specific class A, B and C agonistic CpG-oligodeoxynucleotide (ODN) treatment vs ODN controls in 3T3-L1 adipocytes and in primary murine adipocytes from Tlr9
wt/wt vs Tlr9-/- mice. We found that TLR9 gene expression is induced during AD and that T LR9 protein is expressed in murine gonadal and human visceral adipocytes. AD depends on intact TLR9 expression. Tlr9-/- mice demonstrate significantly reduced adiponectin serum levels, while siRNAmediated TLR9 knockdown led to reduced adiponectin mRNA expression in adipocytes. TLR9 ligands (CpG-ODNs) inhibit pro-inflammatory resistin secretion in mature 3T3-L1 adipocytes. Tlr9-/- as compared to Tlr9wt/wt adipocytes exhibit increased resistin and MCP1 secretion and reduced adiponectin secretion into cell culture supernatants, while TLR9 ligands (ODNs) show differential effects in Tlr9-/- vs Tlr9wt/wt primary murine adipocytes. TLR9 expression is significantly increased in visceral compared to subcutaneous adipose tissue depots in non-diabetic obese patients and correlates with systemic resistin levels in a compartment-specific manner. Thus, adipocytic TLR9 is a putative, new protective factor during (obesity-associated) adipose tissue inflammation. [ABSTRACT FROM AUTHOR]- Published
- 2019
- Full Text
- View/download PDF
35. Mechanisms of Disease: adipocytokines and visceral adipose tissue—emerging role in nonalcoholic fatty liver disease
- Author
-
Jürgen Schölmerich, Christa Büchler, and Andreas Schäffler
- Subjects
Leptin ,Liver Cirrhosis ,medicine.medical_specialty ,Adipokine ,Adipose tissue ,chemistry.chemical_compound ,Insulin resistance ,Internal medicine ,Adipocyte ,Nonalcoholic fatty liver disease ,Adipocytes ,medicine ,Humans ,Insulin ,Obesity ,Leptin receptor ,Hepatology ,Adiponectin ,business.industry ,Fatty liver ,Gastroenterology ,General Medicine ,medicine.disease ,Fatty Liver ,Viscera ,Glucose ,Endocrinology ,Adipose Tissue ,chemistry ,Cytokines ,Insulin Resistance ,business ,hormones, hormone substitutes, and hormone antagonists - Abstract
There is increasing evidence that visceral adipose tissue is a causative risk factor for fatty liver and nonalcoholic steatohepatitis. Adipose tissue-derived secretory proteins are collectively named adipocytokines. Obesity and mainly visceral fat accumulation impair adipocyte function and adipocytokine secretion and the altered release of these proteins contributes to hypertension, impaired fibrinolysis and insulin resistance. This review summarizes recent findings on the role of the adipocytokines adiponectin, leptin and resistin in the context of hepatic insulin resistance, fatty liver and liver fibrosis. Elevated levels of resistin antagonize hepatic insulin action and raise plasma glucose levels. Leptin exerts insulin-sensitizing effects, but obesity has been linked to leptin resistance and low levels of circulating leptin receptor, indicating that high levels of leptin cannot mediate its beneficial effects. Adiponectin improves insulin sensitivity; however, low circulating adiponectin is found in the obese state. Adiponectin is an anti-inflammatory protein, whereas leptin augments inflammation and fibrogenesis. Disturbed adipocytokine secretion might, therefore, promote hepatic steatosis and the development of nonalcoholic steatohepatitis. The beneficial effects of the therapeutic approaches so far tested in the treatment of fatty liver disease and fibrosis might be due to the modulation of these adipocytokines.
- Published
- 2005
36. Regulation and function of C1Q/TNF-related protein-5 (CTRP-5) in the context of adipocyte biology
- Author
-
M. Wabitsch, Andrea Kopp, Martina Müller, Charalampos Aslanidis, Andreas Schmid, and Andreas Schäffler
- Subjects
Adult ,Male ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Adipokine ,Adipose tissue ,Polymorphism, Single Nucleotide ,chemistry.chemical_compound ,Mice ,Young Adult ,Endocrinology ,Downregulation and upregulation ,Western blot ,Gene Frequency ,Internal medicine ,Adipocyte ,3T3-L1 Cells ,Internal Medicine ,medicine ,Adipocytes ,Animals ,Humans ,adipocyte protein 2 ,RNA, Small Interfering ,Cells, Cultured ,Gene knockdown ,Adipogenesis ,biology ,Adiponectin ,medicine.diagnostic_test ,Membrane Proteins ,General Medicine ,Middle Aged ,Mice, Inbred C57BL ,chemistry ,Diabetes Mellitus, Type 2 ,Gene Expression Regulation ,Case-Control Studies ,biology.protein ,Female - Abstract
The C1q/TNF-related protein (CTRP) family represents a growing family of adiponectin paralogous proteins. CTRP-5 was detected in adipose tissue of mice and plays a role in the context of the metabolic syndrome. It was the aim to investigate the detailed expression profile of CTRP-5 in a variety of adipocytic cells and to determine whether CTRP-5 circulates in human serum. Moreover, regulation and function of CTRP-5 was studied in the context of adipocyte biology. CTRP-5 serum levels were measured in 50 healthy subjects by ELISA. Genotype analysis was performed by direct sequencing in 200 probands. CTRP-5 mRNA and protein expression was analyzed by RT-PCR, real-time RT-PCR and Western blot. Recombinant CTRP-5 and fatty acids were used for stimulation experiments in 3T3-L1 adipocytes. siRNA-mediated knockdown of CTRP-3 was performed during adipocyte differentiation. CTRP-5 mRNA and protein was strongly expressed in a wide variety of human and murine adipocytic cells and was induced during adipocyte differentiation. Saturated fatty acids increased CTRP-5 expression in adipocytes. siRNA-mediated cellular knockdown of CTRP-3 in adipocytes resulted in an upregulation of CTRP-5 expression. CTRP-5 inhibited the release of resistin and adiponectin dose-dependently. CTRP-5 circulates abundantly in human sera with a broad interindividual variation. The SNP 1014 T/A was not associated with type 2 diabetes mellitus in 200 Caucasian probands. CTRP-5 might be a novel adipokine that circulates abundantly in human sera. CTRP-5 is functionally involved in adipocyte biology and there might exist a counter-regulatory connection with its family member, CTRP-3.
- Published
- 2013
37. The novel adipokine C1q/TNF-related protein-3 is expressed in human adipocytes and regulated by metabolic and infection-related parameters
- Author
-
Andreas Schäffler, Frank Hanses, Andrea Kopp, Andreas Schmid, Margarita Bala, and Martina Müller
- Subjects
medicine.medical_specialty ,Staphylococcus aureus ,Epinephrine ,Endocrinology, Diabetes and Metabolism ,Lipolysis ,Blotting, Western ,Subcutaneous Fat ,Adipose tissue ,Adipokine ,Biology ,Intra-Abdominal Fat ,chemistry.chemical_compound ,Mice ,Endocrinology ,Western blot ,Adipokines ,Adipocyte ,Internal medicine ,3T3-L1 Cells ,Internal Medicine ,medicine ,Animals ,Humans ,Insulin ,Resistin ,Gene Silencing ,Cells, Cultured ,Gene knockdown ,medicine.diagnostic_test ,Adiponectin ,General Medicine ,Staphylococcal Infections ,Recombinant Proteins ,chemistry ,Diabetes Mellitus, Type 2 ,Gene Expression Regulation ,Tumor Necrosis Factors ,Female ,Tumor Necrosis Factor Inhibitors - Abstract
BACKGROUND The growing family of C1Q/TNF-related proteins is characterized by structural homologies to the anti-inflammatory adipokine adiponectin. CTRP-3 was recently reported to function as an anti-inflammatory LPS-antagonist in vitro. MATERIAL AND METHODS Human subcutaneous and visceral adipocytes and murine 3T3-L1 adipocytes were used for analysis of CTRP-3 expression and function. Western blot analysis of CTRP-3, siRNA mediated knockdown of CTRP-3, Oil red O staining, assessment of basal and epinephrine-induced lipolysis, ELISA-based measurements of supernatant chemokines, recombinant CTRP-3 protein expression, and Staphylococcus aureus (S. aureus) infection assays were used. RESULTS CTRP-3 is expressed in subcutaneous and visceral adipocytes. CTRP-3 is positively regulated by insulin, whereas chronic LPS-exposure inhibits terminal adipocyte differentiation and CTRP-3 expression. Intracellular infection of adipocytes by S. aureus also decreases CTRP-3 expression. As demonstrated by siRNA-mediated cellular knockdown of CTRP-3 in adipocytes, CTRP-3 regulates resistin secretion and lipolysis. CONCLUSION CTRP-3 is expressed in human adipocytes and plays an important role in adipocyte physiology such as lipolysis and adipokine secretion. Both, metabolic factors and infection/inflammation-related factors regulate CTRP-3 expression.
- Published
- 2012
38. Toll-like receptor ligands cause proinflammatory and prodiabetic activation of adipocytes via phosphorylation of extracellular signal-regulated kinase and c-Jun N-terminal kinase but not interferon regulatory factor-3
- Author
-
Andreas Schäffler, Markus Neumeier, Christa Buechler, J. Schölmerich, Margarita Bala, and Andrea Kopp
- Subjects
MAPK/ERK pathway ,Adult ,Lipopolysaccharides ,Male ,MAP Kinase Signaling System ,MAP Kinase Kinase 2 ,MAP Kinase Kinase 1 ,Adipose tissue ,Biology ,Proinflammatory cytokine ,chemistry.chemical_compound ,Mice ,Endocrinology ,Adipocyte ,3T3-L1 Cells ,Nitriles ,Adipocytes ,Butadienes ,Animals ,Humans ,Insulin ,RNA, Messenger ,Phosphorylation ,Extracellular Signal-Regulated MAP Kinases ,Chemokine CCL2 ,Anthracenes ,Inflammation ,Interleukin-6 ,c-jun ,Toll-Like Receptors ,JNK Mitogen-Activated Protein Kinases ,Molecular biology ,chemistry ,Adipose Tissue ,Mitogen-activated protein kinase ,Myeloid Differentiation Factor 88 ,biology.protein ,Female ,Interferon Regulatory Factor-3 ,Signal transduction - Abstract
Here, we aim to investigate the mechanisms of Toll-like receptor (TLR)-induced prodiabetic and proinflammatory activation of adipocytes and to detect differences in the responsiveness of TLRs to their respective ligands between adipocytes isolated from inflamed vs. noninflamed adipose tissue. Experiments using specific ligands for all known TLRs were performed in murine 3T3-L1 adipocytes and in human adipocytes isolated from noninflamed and inflamed adipose tissue. IL-6 and monocyte chemoattractant protein-1 (MCP-1) release were measured by ELISA. The expression of the signal transduction proteins phospho-extracellular signal-regulated kinase (P-Erk), P-c-Jun N-terminal kinase (JNK), and P-interferon regulatory factor-3 was investigated by Western blot analysis. Additionally, functional inhibitors of MAPK kinase-1/-2 and JNK-1/-2 were used in the stimulation experiments. Activation of TRL4 by lipopolysaccharide (LPS) and TLR1/2 by Pam3Cys up-regulates IL-6 and MCP-1 release in adipocytes via specific activation of Erk. Stimulation of adipocytes by macrophage activating lipopeptide-2 (MALP-2) induces MCP-1 but has no effect on IL-6 release. This stimulatory effect on MCP-1 release is antagonized by inhibition of both mitogen-activated protein kinase-1/-2 and JNK-1/-2. Phosphorylation of Erk and JNK is up-regulated after stimulation by MALP-2. In human adipocytes isolated from noninflamed adipose tissue, LPS and Pam3Cys, but not MALP-2, are potent inducers of IL-6 and MCP-1. MALP-2 is able to induce IL-6 and MCP-1 release in adipocytes isolated from inflamed adipose tissue, whereas these adipocytes lost their ability to respond to LPS. The present results point to a role of the adipose tissue in innate immunity. TLR-ligand-induced proinflammatory and prodiabetic activation of adipocytes might couple visceral adipose tissue dysfunction with insulin resistance and type 2 diabetes mellitus.
- Published
- 2010
39. Effects of the new C1q/TNF-related protein (CTRP-3) 'cartonectin' on the adipocytic secretion of adipokines
- Author
-
Juergen Schoelmerich, Charalampos Aslanidis, Britta Wölfing, Markus Neumeier, Christa Buechler, Johanna Weigert, and Andreas Schäffler
- Subjects
Leptin ,medicine.medical_specialty ,Endocrinology, Diabetes and Metabolism ,Blotting, Western ,Medicine (miscellaneous) ,Adipokine ,Enzyme-Linked Immunosorbent Assay ,Body Mass Index ,chemistry.chemical_compound ,Mice ,Endocrinology ,Adipokines ,Species Specificity ,Genes, Reporter ,Internal medicine ,Adipocyte ,3T3-L1 Cells ,medicine ,Adipocytes ,Animals ,Humans ,Secretion ,Luciferase ,Resistin ,Receptor ,Promoter Regions, Genetic ,Nutrition and Dietetics ,Adiponectin ,Interleukin-6 ,Recombinant Proteins ,Subcutaneous Fat, Abdominal ,PPAR gamma ,chemistry ,Tumor Necrosis Factors - Abstract
Background: Cartonectin (collagenous repeat-containing sequence of 26-kDa protein; CORS-26) was described as a new adipokine of the C1q/TNF molecular superfamily C1q/TNF-related protein-3 (CTRP-3), secreted by the adipocytes of mice and humans. The receptor and function of cartonectin are unknown and the recombinant protein is not commercially available. Objective: To investigate the effects of recombinant cartonectin on the secretion of adipokines such as adiponectin, leptin, and resistin from adipocytes of human and murine origin. The effect of the BMI of the adipocyte donor was also investigated. Methods and Procedures: Human adipocytes from pooled lean and preobese healthy individuals and murine 3T3-L1 adipocytes were used for stimulation experiments. Recombinant cartonectin was expressed in insect H5 cells. Adipokine secretion was measured using enzyme-linked immunosorbent assay. In addition, western blot analysis and luciferase reporter gene assays were employed. Results: Cartonectin (1, 10, 50, and 250 ng/ml) in higher doses stimulates the secretion of adiponectin and resistin from murine adipocytes. This effect is not caused by an induction of peroxisome proliferator-activated receptor-γ (PPAR-γ) protein expression, as confirmed by western blot analysis. Also, luciferase reporter gene assay revealed that cartonectin failed to induce luciferase activity at the peroxisome proliferator-activated receptor responsive element site containing the adiponectin/luciferase promoter fragment. Human adipocytes from lean individuals secrete higher amounts of adiponectin and leptin when compared with adipocytes of individuals with a preobesity BMI (25–30 kg/m2). Cartonectin failed to stimulate adiponectin or leptin secretion from human adipocytes, irrespective of the BMI value. Discussion: Cartonectin is a new adipokine that differentially regulates the secretion of classical adipokines, with marked differences between the human and the murine systems. These effects are species-dependent, while basal adipokine secretion is influenced by the BMI.
- Published
- 2008
40. The emerging role of bile acids in white adipose tissue.
- Author
-
Schmid, Andreas, Karrasch, Thomas, and Schäffler, Andreas
- Subjects
- *
WHITE adipose tissue , *BILE acids , *BROWN adipose tissue , *PERIPHERAL circulation , *TYPE 2 diabetes - Abstract
Bile acids (BAs) in the peripheral circulation represent a specific but underestimated physiological compartment Systemic (peripheral) BAs can be regarded as specific steroidal hormones that act on white adipocytes. The term 'bilokines' ('bile hormones') is suggested for peripheral BAs subspecies acting on specific receptors on adipocytes and peripheral tissues other than gut or liver. Adipoflammation and metaflammation in visceral obesity represent the main and causal mechanisms for insulin resistance and type 2 diabetes mellitus (T2D), and can be targeted by BAs in an anti-inflammatory manner. The kinetics of systemic BA subspecies upon feeding and bariatric surgery represents a widely uncharacterized black box whose decipherment could help to identify single BAs as druggable targets in obesity, T2D, and metabolic syndrome. The effects of bile acids (BAs) on liver, enteroendocrine function, small intestine, and brown adipose tissue have been described extensively. Outside the liver, BAs in the peripheral circulation system represent a specific but underappreciated physiological compartment. We discuss how systemic BAs can be regarded as specific steroidal hormones that act on white adipocytes, and suggest the name 'bilokines' ('bile hormones') for the specific FXR/TGR5 receptor interaction in adipocytes. Some BAs and their agonists regulate adipocyte differentiation, lipid accumulation, hypoxia, autophagy, adipokine and cytokine secretion, insulin signaling, and glucose uptake. BA signaling could provide a new therapeutic avenue for adipoflammation and metaflammation in visceral obesity, the causal mechanisms underlying insulin resistance and type 2 diabetes mellitus (T2D). [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. CTRP-3 is permeable to the blood-brain barrier and is not regulated by glucose or lipids in vivo.
- Author
-
Schmid, Andreas, Berghoff, Martin, Hochberg, Alexandra, Schäffler, Andreas, and Karrasch, Thomas
- Subjects
PROTEIN analysis ,ADIPOKINES ,PEPTIDE hormones ,BLOOD-brain barrier ,GLUCOSE tolerance tests ,FAT cells - Abstract
Background C1q/ TNF-related protein-3 ( CTRP-3) represents a novel anti-inflammatory and antidiabetic adipokine secreted by adipose tissue. The physiological and postprandial regulation of CTRP-3 remains obscure and it is not known whether CTRP-3 is permeable to the brain. The postprandial regulation of CTRP-3 during an oral glucose tolerance test ( n = 100) and an oral lipid tolerance test ( n = 100) in humans was investigated. Moreover, CTRP-3 concentrations were measured in paired serum and cerebrospinal fluid ( CSF) samples of patients ( n = 270) undergoing neurological evaluation. The expression of CTRP-3 mRNA was investigated in adipocytes upon stimulation with glucose, sex hormones and a broad panel of fatty acids. Materials and methods Serum and CSF CTRP-3 concentrations were measured by ELISA. 3T3-L1 adipocytes were used for stimulation experiments. CTRP-3 mRNA expression was quantified by using real-time PCR analysis. Results CTRP-3 is present in human cerebrospinal fluid with a mean CSF/serum ratio of 110 ± 64 × 10
−3 . CTRP-3 is not regulated postprandially by carbohydrates or lipids in the healthy state. Females have slightly higher levels of CTRP-3 when compared to males. A significant and positive correlation of CTRP-3 to LDL cholesterol serum levels is reproducible in several cohorts and deserves further mechanistic investigation. Whereas glucose concentrations do not influence CTRP-3 mRNA expression in 3T3-L1 adipocytes in vitro, fatty acids differentially modulate CTRP-3 expression. Conclusions The novel adipokine CTRP-3 is detectable in human cerebrospinal fluid (proof of principle). Due to its blood-brain barrier permeability, CTRP-3 represents a novel putative candidate for a physiological regulator molecule affecting central nervous functions. [ABSTRACT FROM AUTHOR]- Published
- 2017
- Full Text
- View/download PDF
42. Genomic structure of human omentin, a new adipocytokine expressed in omental adipose tissue
- Author
-
Andreas Schäffler, Christa Büchler, Markus Neumeier, J. Schölmerich, Hans H Herfarth, and Alois Fürst
- Subjects
Adult ,Male ,medicine.medical_specialty ,Molecular Sequence Data ,Biophysics ,Context (language use) ,Intelectin ,Biology ,GPI-Linked Proteins ,Biochemistry ,chemistry.chemical_compound ,Structural Biology ,Internal medicine ,Adipocyte ,Lectins ,Genetics ,medicine ,Humans ,Amino Acid Sequence ,RNA, Messenger ,Promoter Regions, Genetic ,Gene ,Peptide sequence ,Crohn's disease ,Binding Sites ,Base Sequence ,Genome, Human ,Promoter ,Exons ,Genomics ,Middle Aged ,medicine.disease ,Endocrinology ,chemistry ,Adipose Tissue ,Cytokines ,Female ,Primer (molecular biology) ,Hydrophobic and Hydrophilic Interactions ,Omentum - Abstract
Genomic structure, promoter region, amino acid sequence and exon-specific primer combinations of the human omentin gene are presented. Omentin mRNA expression differs between omental adipose tissue probes from patients with chronic inflammatory bowel diseases such as Crohn's disease. Sequence comparisons revealed a 100% identity of omentin with human intelectin. Based on this, omentin might be a new adipocytokine playing a role in the defense against intestinal bacterial translocation in the context of Crohn's disease.
- Published
- 2005
43. Hypothesis paper Brain talks with fat--evidence for a hypothalamic-pituitary-adipose axis?
- Author
-
J. Schölmerich, N. Binart, Christa Büchler, and Andreas Schäffler
- Subjects
Receptors, Neuropeptide ,endocrine system ,medicine.medical_specialty ,Pituitary gland ,Vasopressin ,Hypothalamo-Hypophyseal System ,Adipose tissue ,Pituitary-Adrenal System ,Biology ,Cellular and Molecular Neuroscience ,chemistry.chemical_compound ,Endocrinology ,Internal medicine ,Adipocyte ,medicine ,Humans ,Receptor ,Endocrine and Autonomic Systems ,Prolactin receptor ,General Medicine ,medicine.anatomical_structure ,Neurology ,Oxytocin ,chemistry ,Adipose Tissue ,Hypothalamus ,hormones, hormone substitutes, and hormone antagonists ,medicine.drug - Abstract
The adipose tissue signals to the brain via its secretory products. However, it is unknown whether the brain itself can directly contact the fat tissue. In order to test this hypothesis, the adipocytic expression of receptors for pituitary hormones and hypothalamic peptides was investigated. Besides FSH- and LH-receptors, adipocytes do express the specific receptors for ACTH, TSH, GH, prolactin, oxytocin and the three receptor subtypes for vasopressin. Thus, the adipose tissue might no longer be regarded as an inert and steady tissue but as a fast acting player downstream of and under the control of the brain. Based on this, the potential existence and clinical impact of a hypothalamic-pituitary-adipose axis should further be investigated.
- Published
- 2005
44. Role of specificity protein-1, PPARgamma, and pituitary protein transcription factor-1 in transcriptional regulation of the murine CORS-26 promoter
- Author
-
A Schäffler, A Ehling, E Neumann, H Herfarth, G Paul, I Tarner, S Gay, C Buechler, J Schölmerich, and U Müller-Ladner
- Subjects
Transcriptional Activation ,Sequence analysis ,Sp1 Transcription Factor ,Biophysics ,Receptors, Cytoplasmic and Nuclear ,Biology ,Biochemistry ,Binding, Competitive ,chemistry.chemical_compound ,Mice ,Adipokines ,Structural Biology ,Genes, Reporter ,Adipocyte ,3T3-L1 Cells ,Genetics ,Transcriptional regulation ,Adipocytes ,Animals ,Binding site ,Luciferases ,Promoter Regions, Genetic ,Gene ,Transcription factor ,Cells, Cultured ,Regulation of gene expression ,Cell Nucleus ,Binding Sites ,Oligonucleotide ,Proteins ,Cell Differentiation ,Molecular biology ,Protein Structure, Tertiary ,DNA-Binding Proteins ,chemistry ,Gene Expression Regulation ,Mutation ,NIH 3T3 Cells ,Transcription Factor Pit-1 ,Software ,Protein Binding ,Transcription Factors - Abstract
The collagenous repeat-containing sequence of 26-kDa protein (CORS-26) was recently described as a new gene that is induced during adipocyte differentiation. Since the transcription factors specificity protein-1 (SP-1) and PPARgamma have been demonstrated to modulate transcriptional activation of adipocytic genes, we investigated the putative role of SP-1 and PPARgamma in the regulation of the murine CORS-26 promoter. Computer-based sequence analysis revealed two putative SP-1 binding sites and binding sites for PPARgamma and Pit-1 within the TATA-box containing promoter. Electrophoretic mobility shift assays (EMSA) with nuclear extracts from 3T3-L1 adipocytes and appropriate promoter fragments demonstrated that SP-1 binds specifically to both SP-1 binding sites. Specificity was demonstrated by (i) the appearance of supershift bands, (ii) competition experiments and, (iii) by using oligonucleotides carrying mutated SP-1 binding sites. Functional promoter activity was analyzed by Luciferase reporter gene assays and SP-1 was shown to exert inhibitory effects on the transcriptional activation of the murine CORS-26 gene. Additionally, specific binding activity of PPARgamma and Pit-1 to the CORS-26 promoter was demonstrated. Taken together, the present data demonstrate the functionality of the proximal murine CORS-26 promoter, which is regulated specifically by two SP-1 binding sites via SP-3-independent repressive effects of SP-1 on transcriptional activation. Pit-1 and PPARgamma can bind specifically to the promoter and might play an additive functional role in gene regulation of murine CORS-26.
- Published
- 2003
45. Identification of regulatory elements in the human adipose most abundant gene transcript-1 ( apM-1) promoter: role of SP1/SP3 and TNF-alpha as regulatory pathways
- Author
-
Thomas Langmann, J. Schölmerich, N. Barth, Gerd Schmitz, and Andreas Schäffler
- Subjects
Transcription, Genetic ,Sp1 Transcription Factor ,Cellular differentiation ,Endocrinology, Diabetes and Metabolism ,Recombinant Fusion Proteins ,Biology ,Regulatory Sequences, Ribonucleic Acid ,Transfection ,chemistry.chemical_compound ,Mice ,Adipocyte ,Gene expression ,Internal Medicine ,Adipocytes ,Animals ,Homeostasis ,Humans ,Binding site ,Cloning, Molecular ,Luciferases ,Promoter Regions, Genetic ,Transcription factor ,Sp1 transcription factor ,Tumor Necrosis Factor-alpha ,Proteins ,Cell Differentiation ,3T3 Cells ,Molecular biology ,DNA-Binding Proteins ,Sp3 Transcription Factor ,chemistry ,Regulatory sequence ,Adipogenesis ,Intercellular Signaling Peptides and Proteins ,Adiponectin ,Transcription Factors - Abstract
Aims/hypothesis. The human adipocyte-specific apM-1 (adipose most abundant gene transcript-1) gene encodes for a secretory protein of the adipose tissue that seems to play a role in the pathogenesis of obesity-related insulin resistance and its expression is inhibited by TNF-α. Our aim was to characterize the tissue-specific regulation of the recently cloned apM-1 promoter and the mechanisms of TNF-α-induced downregulation of the apM-1 gene. Methods. We characterised the apM-1 gene by electrophoretic mobility shift assays (EMSA) and luciferase reporter gene assays (LRA). Results. Although several putative binding sites for transcription factors known to be involved in adipogenesis such as C/EBP and PPARγ are present in the promoter, we could not detect any binding of these nuclear proteins from differentiated adipocytes. However, a proximal SP1 binding site specifically binds both, recombinant SP1 protein and SP1 derived from adipocyte nuclear extracts. Since the expression of SP1 during adipocyte differentiation has not yet been analysed, we could show by using EMSA, that binding activity of SP1 is increased during adipocyte differentiation. The stimulatory activity of SP1 was confirmed in LRA by cotransfection experiments in S2 Schneider cells lacking endogenous SP factors. An inhibitory activity of SP3 on the stimulatory effect of SP1 could be confirmed in LRA by contransfection experiments in adipocytes. Nuclear extracts from adipocytes incubated with TNF-α showed a reduced binding activity of SP1. Conclusion/interpretation. SP1 is expressed and its binding activity is enhanced during adipocyte differentiation. SP1 has stimulatory effects, SP3 has inhibitory effects on apM-1 promoter activity, mediated by a proximal SP1 binding site. The mechanism of TNF-α-induced inhibition of apM-1 gene expression is, at least in part, due to a decrease of transcriptional SP1 binding activity caused by TNF-α and thus provides a new mechanism of TNF-α-dependent signalling.
- Published
- 2002
46. The human apM-1, an adipocyte-specific gene linked to the family of TNF's and to genes expressed in activated T cells, is mapped to chromosome 1q21.3-q23, a susceptibility locus identified for familial combined hyperlipidaemia (FCH)
- Author
-
K.-D. Palitzsch, Evelyn Orsó, J. Schölmerich, Alois Fürst, Gerd Schmitz, Andreas Schäffler, Christa Büchler, and Wolfgang Drobnik
- Subjects
Genetic Linkage ,T-Lymphocytes ,Molecular Sequence Data ,Biophysics ,Hyperlipidemia, Familial Combined ,Biology ,Lymphocyte Activation ,Biochemistry ,chemistry.chemical_compound ,Exon ,Mice ,Genetic linkage ,Adipocyte ,Sequence Homology, Nucleic Acid ,Animals ,Humans ,Genetic Predisposition to Disease ,Amino Acid Sequence ,RNA, Messenger ,Promoter Regions, Genetic ,Molecular Biology ,Peptide sequence ,Gene ,In Situ Hybridization, Fluorescence ,Genetics ,Base Sequence ,Tumor Necrosis Factor-alpha ,Chromosome Mapping ,Proteins ,Cell Biology ,3T3 Cells ,Exons ,Molecular biology ,Introns ,DNA binding site ,Secretory protein ,chemistry ,Chromosomes, Human, Pair 1 ,Intercellular Signaling Peptides and Proteins ,Adiponectin ,Primer (molecular biology) - Abstract
The human adipocyte-specific apM-1 gene encodes a secretory protein of the adipose tissue that has been suggested to play a role in the pathogenesis of obesity. The regulation of apM-1 was studied along adipocyte differentiation. While apM-1-mRNA and apM-1 protein were absent in preadipocytes and in 48 h differentiated adipocytes, they were found upregulated from day 4 to day 9 of adipocyte differentiation as shown by RNase protection assay and Western blot analysis. These data indicate that apM-1 may be a late marker of adipocyte differentiation. In human sera apM-1 protein is also detectable by Western blots using a polyclonal antibody raised against a synthetic peptide sequence of the human apM-1. The genomic structure of the human apM-1 gene together with a total of 2.7 kb of the 5'-flanking region with putative transcription factor binding sites is presented. Interestingly, sequence comparisons link the apM-1 gene to the family of TNF's and to genes expressed in activated T-cells. The chromosomal localization of apM-1 was investigated by FISH and mapped to human chromosome 1q21.3-1q23, a region that was identified as a susceptibility locus for Familial Combined Hyperlipidaemia (FCH) and polygenic NIDDM. These data and the chromosomal localization on chromosome 1q21.3-q23 raises the possibility that apM-1 as an adipocyte-specific secretory protein may play a role in the pathogenesis of FCH and associated insulin resistance. Exon- and intron-specific primer sequences are presented as a basis for mutation screening of patients affected with FCH.
- Published
- 1999
47. Regulation and Function of C1Q/TNF-related Protein-5 (CTRP-5) in the Context of Adipocyte Biology.
- Author
-
Schmid, A., Kopp, A., Aslanidis, C., Wabitsch, M., Müller, M., and Schäffler, A.
- Subjects
FAT cells ,ADIPONECTIN ,PROTEINS ,ADIPOKINES ,ADIPOSE tissues ,SINGLE nucleotide polymorphisms - Abstract
Background and aim: The C1q/TNF-related protein (CTRP) family represents a growing family of adiponectin paralogous proteins. CTRP-5 was detected in adipose tissue of mice and plays a role in the context of the metabolic syndrome. It was the aim to investigate the detailed expression profile of CTRP-5 in a variety of adipocytic cells and to determine whether CTRP-5 circulates in human serum. Moreover, regulation and function of CTRP-5 was studied in the context of adi-pocyte biology. Material and methods: CTRP-5 serum levels were measured in 50 healthy subjects by ELISA. Genotype analysis was performed by direct sequencing in 200 probands. CTRP-5 mRNA and protein expression was analyzed by RT-PCR, realtime RT-PCR and Western blot. Recombinant CTRP-5 and fatty acids were used for stimulation experiments in 3T3-L1 adipocytes. siRNA-mediated knockdown of CTRP-3 was performed during adipocyte differentiation. Results: CTRP-5 mRNA and protein was strongly expressed in a wide variety of human and murine adipocytic cells and was induced during adipocyte differentiation. Saturated fatty acids increased CTRP-5 expression in adipocytes. siRNA-mediated cellular knockdown of CTRP-3 in adipocytes resulted in an upregulation of CTRP-5 expression. CTRP-5 inhibited the release of resistin and adiponectin dose-dependently. CTRP-5 circulates abundantly in human sera with a broad interindividual variation. The SNP 1014 T/A was not associated with type 2 diabetes mellitus in 200 Caucasian probands. Conclusions: CTRP-5 might be a novel adipok-ine that circulates abundantly in human sera. CTRP-5 is functionally involved in adipocyte biology and there might exist a counter-regulatory connection with its family member, CTRP-3. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
48. Peritoneal fluid adipokines: ready for prime time?
- Author
-
Wiest, R., Leidl, F., Kopp, A., Weigert, J., Neumeier, M., Buechler, C., Schoelmerich, J., and Schäffler, A.
- Subjects
CYTOKINES ,ADIPOSE tissues ,ASCITES ,PERITONITIS ,FAT cells ,LEPTIN ,BODY mass index ,DIAGNOSIS ,PATIENTS - Abstract
Background Visceral adipose tissues secret a variety of adipokines; however, it is not known whether they are present in the peritoneal fluid. It was the aim of this study to investigate peritoneal fluid concentrations of novel (cartonectin, omentin) and classical adipokines (leptin, adiponectin, resistin, visfatin) in patients with ascites. Material and methods Ninety-six patients (71 men and 25 women) undergoing paracentesis were included. Of these, 76 suffered from liver cirrhosis. Adipokines were measured by enzyme-linked immunosorbent assay or Western blot. Results Each adipokine was detected in ascites with a broad range. Serum–ascites ratios (SAR) correlated with clinical and laboratory parameters. The main variables influencing peritoneal fluid adipokine concentrations were body mass index (BMI), local inflammation, systemic inflammation and serum adipokine concentrations. Resistin was significantly higher in patients with peritonitis and showed a positive correlation with peripheral leucocytes (white blood cell count). Leptin was correlated with the underlying disease. Visfatin correlated with peripheral white blood cell and C-reactive protein levels. Omentin expression was correlated with ascitic leucocyte count, ascitic albumin concentration and low albumin SAR. BMI was correlated positively with ascitic leptin levels and cartonectin protein levels. Conclusions Peritoneal fluid adipokine concentrations are characterized by individual SARs, depend on the presence of peritonitis, and correlate with underlying disease, BMI and systemic inflammation. The data open a new field of research on the role of the peritoneum and visceral adipokines in gastrointestinal diseases. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
49. Concise Review: Adipose Tissue-Derived Stromal Cells--Basic and Clinical Implications for Novel Cell-Based Therapies.
- Author
-
Schäffler, Andreas and Büchler, Christa
- Subjects
CELLULAR therapy ,BONE marrow ,STEM cells ,ADIPOSE tissues ,LIVER cells ,NEURONS ,HEART cells - Abstract
Compared with bone marrow-derived mesenchymal stem cells, adipose tissue-derived stromal cells (ADSC) do have an equal potential to differentiate into cells and tissues of mesodermal origin, such as adipocytes, cartilage, bone, and skeletal muscle. However, the easy and repeatable access to subcutaneous adipose tissue and the simple isolation procedures provide a clear advantage. Since extensive reviews focusing exclusively on ADSC are rare, it is the aim of this review to describe the preparation and isolation procedures for ADSC, to summarize the molecular characterization of ADSC, to describe the differentiation capacity of ADSC, and to discuss the mechanisms and future role of ADSC in cell therapy and tissue engineering. An initial effort has also been made to differentiate ADSC into hepatocytes, endocrine pancreatic cells, neurons, cardiomyocytes, hepatocytes, and endothelial/vascular cells. Whereas the lineage-specific differentiation into cells of mesodermal origin is well understood on a molecular basis, the molecular key events and transcription factors that initially allocate the ADSC to a lineage-specific differentiation are almost completely unknown. Decoding these molecular mechanisms is a prerequisite for developing novel cell therapies. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
50. Regulation and Function of Collagenous Repeat Containing Sequence of 26-kDa Protein Gene Product "Cartonectin.".
- Author
-
Schäffler, Andréas, Weigert, Johanna, Neumeier, Markus, Schölmerich, Juergen, and Buechler, Christa
- Subjects
PROTEINS ,GENES ,BIOMOLECULES ,BIOCHEMISTRY ,PROTEOMICS - Abstract
The article presents the research which assessed the regulation and function of collagenous repeat containing sequence of 26-kDa protein gene product cartonectin. Based on the outcome of the study, researchers suggest cartonectin, encoded by the CORS-26 gene, to represent a new adipokine belonging to the C1q-complement family of proteins with a N-terminal collagenous domain.
- Published
- 2007
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.