49 results on '"Gizard F"'
Search Results
2. Phenotypic functional activities of monocyte change during crosstalk with breast cancer cell and enhancing effect of metformin of IFN-γ-associated antitumor cytokine production
- Author
-
Lynda Addou-Klouche, Aida Messaoud, Mostefaoui M, Ned J.C. Lamb, Sara Dahou, Wafa Nouari, Mourad Aribi, Gizard F, Anne Fernandez, Miliani M, Benaissti Mi, Gérard Lefranc, Terbeche H, Zoheir Dahmani, and Djebri Nc
- Subjects
Chemistry ,medicine.medical_treatment ,Monocyte ,Autologous Monocytes ,medicine.disease ,Metformin ,Cytokine ,medicine.anatomical_structure ,Breast cancer ,Downregulation and upregulation ,Cancer cell ,medicine ,Cancer research ,Cytotoxicity ,medicine.drug - Abstract
BackgroundImmune activities of monocytes (MOs) can be altered within the microenvironment of solid malignancies, including breast cancer. Metformin (1,1-dimethylbiguanide hydrochloride, MET), has been shown to decrease tumor cell proliferation, but its effects have yet to be explored with respect to the crosstalk between monocytes and breast cancer cells. Here, we investigated the effects of MET on overall phenotypic functional activities of autologous MOs during the interplay with primary breast cancer cells.MethodsHuman primary breast cancer cells were either cultured alone or co-cultured with autologous MOs before treatment with MET.ResultsMET downregulated both breast cancer cell proliferation and the ratio of phosphorylated Akt (p-Akt)-to-Akt in breast cancer cells. Additionally, we observed that, in the absence of MET treatment, the levels of LDH-based cytotoxicity, catalase, intracellular free calcium ions (ifCa2+), IL-10 and arginase activity were significantly reduced in co-cultures compared to those of MOs cultivated alone whereas levels of iNOS were significantly increased (for all comparisons, p < 0.05). In contrast, MET upregulated breast cancer cell LDH-based cytotoxicity levels when co-cultured with MO. MET also induced upregulation of both the inducible enzymatic activity of nitric oxide synthase (iNOS) and arginase activity in MO cells and co-culture systems, although these differences did not reach significant levels for iNOS activity (p > 0.05). MET greatly decreased phagocytic activity in isolated MOs while inducing a robust increase of catalase activity in co-culture systems and of superoxide dismutase (SOD) activity in MOs, but not in MOs co-cultured with breast cancer cells. MET strongly upregulated the levels of ifCa2+ in co-culture systems and IFN-γ production in both isolated MOs and co-culture systems. Moreover, MET treatment markedly downregulated IL-10 production in MOs, while inducing a slight increase in co-cultures (p > 0.05).ConclusionsOur results show that the phenotypic functional activities of MOs change when co-cultured with primary human breast cancer cells. Furthermore, treatment with MET induced enhancing effects on the production of antitumor cytokine IFN-γ and ifCa2+, as well as cytotoxicity during breast cancer cell-MO crosstalk.Novel Highlights includeFirst analysis of the anti-tumoral effects of Metformin on primary human breast cancer cells and the crosstalk with autologous monocytes.Phenotypic functional activities of monocytes change during their interplay with breast cancer cells, which is improved by upregulation of IFN-γ after Metformin treatment.Metformin induces downregulation of phosphorylated-Akt1/2-to-Akt1/2 ratio in breast cancer cells.Metformin downregulates phagocytic capacity of monocyte from breast cancer patients.
- Published
- 2020
3. A test set-up for the analysis of multi-tone intermodulation in microwave devices
- Author
-
Teyssier, J. P., primary, Sombrin, J., additional, Quere, R., additional, Laurent, S., additional, and Gizard, F., additional
- Published
- 2014
- Full Text
- View/download PDF
4. Caractérisation temporelle de signaux multi-tons en utilisant l'analyseur de réseau fort signal (LSNA)
- Author
-
Abou Chahine, Mouhamad, El Yaagoubi, Mohamed, Neveux, Guillaume, Barataud, Denis, Nebus, Jean-Michel, Gizard, F., Lebraud, Sophie, C2S2, XLIM (XLIM), and Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)
- Published
- 2007
5. Un role pour PPAR gamma dans la reproduction
- Author
-
Pascal Froment, Gizard, F., Bart Staels, Joëlle Dupont, Philippe Monget, Flanders Institute for Biotechnology, Physiologie de la reproduction et des comportements [Nouzilly] (PRC), Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur]-Université de Tours-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Institut Français du Cheval et de l'Equitation [Saumur]-Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS), and ProdInra, Migration
- Subjects
[SDV] Life Sciences [q-bio] ,[SDV]Life Sciences [q-bio] ,[INFO]Computer Science [cs] ,[INFO] Computer Science [cs] ,ComputingMilieux_MISCELLANEOUS - Abstract
National audience
- Published
- 2005
6. Predistortion System Implementation Based On Analog Neural Networks For Linearizing High Power Amplifiers Transfer Characteristics
- Author
-
Mulliez, B., primary, Moutaye, E., additional, Tap, H., additional, Gatet, L., additional, and Gizard, F., additional
- Published
- 2014
- Full Text
- View/download PDF
7. Study of the boundary layer and low troposphere in the area of Marseille. Time evolution of the vertical stratification through ground remote-sensed data
- Author
-
Delbarre, H., Augustin, P., Benech, B., Bernard Campistron, Emeric FREJAFON, Gizard, F., Fabienne Lohou, Clotilde Moppert, Puygrenier, V., Saïd, F., Laboratoire de Physico-Chimie de l'Atmosphère (LPCA), and Université du Littoral Côte d'Opale (ULCO)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics] - Published
- 2003
8. X BAND MMIC direct 8 Phase Shift Keying modulator for high data rate earth observation applications
- Author
-
Boulanger, C., Lapierre, L., Gizard, F., Zanchi, C., and Lesthievent, G.
- Subjects
ING-INF/01 Elettronica - Abstract
We present a new topology of 8 Phase Shift Keying modulator that allows achieving a very high accuracy of 0.4dB and 3° on the 8-8.4 GHz band in the –10°C to +55°C temperature range, with only one tuning voltage and a very low consumption. The device has been manufactured on the D02AH OMMIC GaAs PHEMT process but has been transposed to other FET foundries. This new topology is covered by a patent [1].It has been transfered and improved by Alcatel Space Industries, to fit industrial quality requirements, in order to define a commercial product of high data rate transmission channel for micro-satellites.
- Published
- 2000
- Full Text
- View/download PDF
9. Experimental validation of fringing field effects for the multipactor phenomenon
- Author
-
Mader, P., primary, Dillenbourg, H., additional, Labourdette, C., additional, Lepeltier, P., additional, Sinigaglia, J., additional, Smits, J., additional, Puech, J., additional, Gizard, F., additional, Lopez, J.M.E., additional, Anderson, D., additional, Lisak, M., additional, Rakova, E.I., additional, and Semenov, V.E., additional
- Published
- 2012
- Full Text
- View/download PDF
10. Embedded updating system based on integrated NNs in order to achieve adaptative predistortion of nonlinear HPA characteristics
- Author
-
Gatet, L., primary, Bony, F., additional, Tap-Beteille, H., additional, Moutaye, E., additional, Jayat, F., additional, Roviras, D., additional, and Gizard, F., additional
- Published
- 2009
- Full Text
- View/download PDF
11. Time-Domain Calibrated Measurements of Wideband Multisines Using a Large-Signal Network Analyzer
- Author
-
El Yaagoubi, M., primary, Neveux, G., additional, Barataud, D., additional, Reveyrand, T., additional, Nebus, J.-M., additional, Verbeyst, F., additional, Gizard, F., additional, and Puech, J., additional
- Published
- 2008
- Full Text
- View/download PDF
12. Peroxisome proliferator-activated receptors in reproductive tissues: from gametogenesis to parturition
- Author
-
Froment, P, primary, Gizard, F, additional, Defever, D, additional, Staels, B, additional, Dupont, J, additional, and Monget, P, additional
- Published
- 2006
- Full Text
- View/download PDF
13. The transcriptional regulating protein of 132 kDa (TReP-132) differentially influences steroidogenic pathways in human adrenal NCI-H295 cells
- Author
-
Gizard, F, primary, Teissier, E, additional, Dufort, I, additional, Luc, G, additional, Luu-The, V, additional, Staels, B, additional, and Hum, DW, additional
- Published
- 2004
- Full Text
- View/download PDF
14. Active and highly integrated antennas studies supported by CNES.
- Author
-
Albert, I., Gizard, F., and Lopez, J.M.E.
- Published
- 2009
15. Integrated CMOS Analog Neural Network Ability to Linearize the Distorted Characteristic of HPA Embedded in Satellites.
- Author
-
Gatet, L., Tap-Beteille, H., Roviras, D., and Gizard, F.
- Published
- 2008
- Full Text
- View/download PDF
16. A new satellite repeater amplifier characterization system for large bandwidth NPR and modulated signals measurements.
- Author
-
Mallet, A., Gizard, F., Reveyrand, T., Lapierre, L., and Sombrin, J.
- Published
- 2002
- Full Text
- View/download PDF
17. X Band MMIC direct 8 Phase Shift Keying modulator for high data rate earth observation applicaions
- Author
-
Boulanger, C., primary, Lapierre, L., additional, Gizard, F., additional, Zanchi, C., additional, and Lesthievent, G., additional
- Published
- 2000
- Full Text
- View/download PDF
18. PPARalpha agonists suppress osteopontin expression in macrophages and decrease plasma levels in patients with type 2 diabetes.
- Author
-
Nakamachi T, Nomiyama T, Gizard F, Heywood EB, Jones KL, Zhao Y, Fuentes L, Takebayashi K, Aso Y, Staels B, Inukai T, and Bruemmer D
- Abstract
Osteopontin (OPN) is a proinflammatory cytokine implicated in the chemoattraction of monocytes and the development of atherosclerosis. Peroxisome proliferator-activated receptor (PPAR)alpha, a ligand-activated transcription factor with pleiotropic anti-inflammatory effects in macrophages, is the molecular target for fibrates, which are frequently used to treat dyslipidemia in patients with type 2 diabetes at high risk for cardiovascular disease. In the present study, we examined the regulation of OPN by PPARalpha agonists in macrophages and determined the effect of fibrate treatment on OPN plasma levels in patients with type 2 diabetes. Treatment of human macrophages with the PPARalpha ligands bezafibrate or WY14643 inhibited OPN expression. PPARalpha ligands suppressed OPN promoter activity, and an activator protein (AP)-1 consensus site conferred this repression. Overexpression of c-Fos and c-Jun reversed the inhibitory effect of PPARalpha ligands on OPN transcription, and, in chromatin immunoprecipitation assays, PPARalpha ligands inhibited c-Fos and phospho-c-Jun binding to the OPN promoter. Moreover, c-Fos and phospho-c-Jun protein expression was inhibited by PPARalpha agonists, indicating that PPARalpha ligands suppress OPN expression through negative cross talk with AP-1-dependent transactivation of the OPN promoter. This inhibitory effect of PPARalpha ligands on OPN expression was absent in PPARalpha-deficient macrophages, suggesting a receptor-mediated mechanism of OPN suppression. Finally, treatment of type 2 diabetic patients with bezafibrate significantly decreased OPN plasma levels. These results demonstrate a novel mechanism whereby PPARalpha ligands may impact macrophage inflammatory responses and decrease early proinflammatory markers for cardiovascular disease. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
19. A new satellite repeater amplifier characterization system for large bandwidth NPR and modulated signals measurements
- Author
-
Mallet, A., primary, Gizard, F., additional, Reveyrand, T., additional, Lapierre, L., additional, and Sombrin, J., additional
- Full Text
- View/download PDF
20. Interactions between gut microbiota and skeletal muscle.
- Author
-
Gizard F, Fernandez A, and De Vadder F
- Abstract
The gut microbiota is now recognized as a major contributor to the host's nutrition, metabolism, immunity, and neurological functions. Imbalanced microbiota (ie, dysbiosis) is linked to undernutrition-induced stunting, inflammatory and metabolic diseases, and cancers. Skeletal muscle also takes part in the interorgan crosstalk regulating substrate metabolism, immunity, and health. Here, we review the reciprocal influence of gut microbiota and skeletal muscle in relation to juvenile growth, performance, aging, and chronic diseases. Several routes involving the vascular system and organs such as the liver and adipose tissue connect the gut microbiota and skeletal muscle, with effects on fitness and health. Therapeutic perspectives arise from the health benefits observed with changes in gut microbiota and muscle activity, further encouraging multimodal therapeutic strategies., Competing Interests: Declaration of Conflicting Interests:The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article., (© The Author(s) 2020.)
- Published
- 2020
- Full Text
- View/download PDF
21. Metformin partially reverses the inhibitory effect of co-culture with ER-/PR-/HER2+ breast cancer cells on biomarkers of monocyte antitumor activity.
- Author
-
Dahmani Z, Addou-Klouche L, Gizard F, Dahou S, Messaoud A, Chahinez Djebri N, Benaissti MI, Mostefaoui M, Terbeche H, Nouari W, Miliani M, Lefranc G, Fernandez A, Lamb NJ, and Aribi M
- Subjects
- Breast Neoplasms drug therapy, Cell Proliferation drug effects, Cells, Cultured, Coculture Techniques, Female, Gene Expression Regulation, Neoplastic drug effects, Humans, L-Lactate Dehydrogenase metabolism, Receptor, ErbB-2 metabolism, Receptors, Estrogen metabolism, Receptors, Progesterone metabolism, Biomarkers metabolism, Breast Neoplasms metabolism, Metformin pharmacology, Monocytes cytology
- Abstract
Background: Immune activities of monocytes (MOs) can be altered within the microenvironment of solid malignancies, including breast cancer. Metformin (1,1-dimethylbiguanide hydrochloride, MET), has been shown to decrease tumor cell proliferation, but its effects have yet to be explored with respect to MOs (monocytes) activity during their crosstalk with breast cancer cells. Here, we investigated the effects of MET on overall phenotypic functional activities, including cellular immunometabolism and protective redox signaling based-biomarkers, intracellular free calcium ions (ifCa2+), phagocytosis and co-operative cytokines (IFN-γ and IL-10) of autologous MOs before and during their interplay with primary ER-/PR-/HER2+ breast cancer cells., Methods: Human primary breast cancer cells were either cultured alone or co-cultured with autologous MOs before treatment with MET., Results: MET downregulated breast cancer cell proliferation and phagocytosis, while having no significant effect on the ratio of phosphorylated Akt (p-Akt) to total Akt. Additionally, we observed that, in the absence of MET treatment, the levels of lactate dehydrogenase (LDH)-based cytotoxicity, catalase, ifCa2+, IL-10 and arginase activity were significantly reduced in co-cultures compared to levels in MOs cultured alone whereas levels of inducible nitric oxide synthase (iNOS) activity were significantly increased. In contrast, MET treatment reduced the effects measured in co-culture on the levels of LDH-based cytotoxicity, arginase activity, catalase, ifCa2+, and IFN-γ. MET also induced upregulation of both iNOS and arginase in MO cells, although the increase did not reach significant difference for iNOS activity. Moreover, MET induced a robust increase of superoxide dismutase (SOD) activity in MOs, but not in MOs co-cultured with breast cancer cells. Furthermore, MET markedly upregulated the levels of IFN-γ production and downregulated those of IL-10 in isolated MOs, while inducing a slight opposing up-regulation of IL-10 production in co-cultures., Conclusions: Our results show that the biomarkers of phenotypic functional activities of MOs are modified after co-culturing with primary human breast cancer cells. Treatment of co-cultures with MET resulted in increased release of antitumor cytokine IFN-γ and ifCa2+, and increased cell necrosis during breast cancer cells-MOs crosstalk., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2020
- Full Text
- View/download PDF
22. Dietary Apigenin in the Prevention of Endothelial Cell Dysfunction.
- Author
-
Lamb NJ and Gizard F
- Subjects
- Diet, Apigenin, Endothelial Cells
- Published
- 2019
- Full Text
- View/download PDF
23. 2',6'-Dihalostyrylanilines, pyridines, and pyrimidines for the inhibition of the catalytic subunit of methionine S-adenosyltransferase-2.
- Author
-
Sviripa VM, Zhang W, Balia AG, Tsodikov OV, Nickell JR, Gizard F, Yu T, Lee EY, Dwoskin LP, Liu C, and Watt DS
- Subjects
- Aniline Compounds chemical synthesis, Aniline Compounds chemistry, Antineoplastic Agents chemical synthesis, Antineoplastic Agents chemistry, Biocatalysis drug effects, Cell Proliferation drug effects, Cell Survival drug effects, Dose-Response Relationship, Drug, Drug Screening Assays, Antitumor, Enzyme Inhibitors chemical synthesis, Enzyme Inhibitors chemistry, HEK293 Cells, Humans, Methionine Adenosyltransferase metabolism, Molecular Structure, Protein Subunits drug effects, Pyridines chemical synthesis, Pyridines chemistry, Pyrimidines chemical synthesis, Pyrimidines chemistry, Stilbenes chemical synthesis, Stilbenes chemistry, Structure-Activity Relationship, Tumor Cells, Cultured, Aniline Compounds pharmacology, Antineoplastic Agents pharmacology, Catalytic Domain drug effects, Enzyme Inhibitors pharmacology, Methionine Adenosyltransferase antagonists & inhibitors, Pyridines pharmacology, Pyrimidines pharmacology, Stilbenes pharmacology
- Abstract
Inhibition of the catalytic subunit of the heterodimeric methionine S-adenosyl transferase-2 (MAT2A) with fluorinated N,N-dialkylaminostilbenes (FIDAS agents) offers a potential avenue for the treatment of liver and colorectal cancers where upregulation of this enzyme occurs. A study of structure-activity relationships led to the identification of the most active compounds as those with (1) either a 2,6-difluorostyryl or 2-chloro-6-fluorostyryl subunit, (2) either an N-methylamino or N,N-dimethylamino group attached in a para orientation relative to the 2,6-dihalostyryl subunit, and (3) either an N-methylaniline or a 2-(N,N-dimethylamino)pyridine ring. These modifications led to FIDAS agents that were active in the low nanomolar range, that formed water-soluble hydrochloride salts, and that possessed the desired property of not inhibiting the human hERG potassium ion channel at concentrations at which the FIDAS agents inhibit MAT2A. The active FIDAS agents may inhibit cancer cells through alterations of methylation reactions essential for cancer cell survival and growth.
- Published
- 2014
- Full Text
- View/download PDF
24. Myeloid-specific IκB kinase β deficiency decreases atherosclerosis in low-density lipoprotein receptor-deficient mice.
- Author
-
Park SH, Sui Y, Gizard F, Xu J, Rios-Pilier J, Helsley RN, Han SS, and Zhou C
- Subjects
- Animals, Atherosclerosis metabolism, Atherosclerosis pathology, Cell Adhesion, Cell Movement, Disease Models, Animal, I-kappa B Kinase genetics, I-kappa B Kinase metabolism, Lipid Metabolism, Macrophages metabolism, Macrophages pathology, Mice, Mice, Inbred C57BL, Mice, Knockout, Receptors, LDL genetics, Receptors, LDL metabolism, Atherosclerosis prevention & control, I-kappa B Kinase deficiency, Myeloid Cells metabolism, Receptors, LDL deficiency
- Abstract
Objective: Inflammatory responses are the driving force of atherosclerosis development. IκB kinase β (IKKβ), a central coordinator in inflammation through regulation of nuclear factor-κB, has been implicated in the pathogenesis of atherosclerosis. Macrophages play an essential role in the initiation and progression of atherosclerosis, yet the role of macrophage IKKβ in atherosclerosis remains elusive and controversial. This study aims to investigate the impact of IKKβ expression on macrophage functions and to assess the effect of myeloid-specific IKKβ deletion on atherosclerosis development., Methods and Results: To explore the issue of macrophage IKKβ involvement of atherogenesis, we generated myeloid-specific IKKβ-deficient low-density lipoprotein receptor-deficient mice (IKKβ(ΔMye)LDLR(-/-)). Deficiency of IKKβ in myeloid cells did not affect plasma lipid levels but significantly decreased diet-induced atherosclerotic lesion areas in the aortic root, brachiocephalic artery, and aortic arch of low-density lipoprotein receptor-deficient mice. Ablation of myeloid IKKβ attenuated macrophage inflammatory responses and decreased atherosclerotic lesional inflammation. Furthermore, deficiency of IKKβ decreased adhesion, migration, and lipid uptake in macrophages., Conclusions: The present study demonstrates a pivotal role for myeloid IKKβ expression in atherosclerosis by modulating macrophage functions involved in atherogenesis. These results suggest that inhibiting nuclear factor-κB activation in macrophages may represent a feasible approach to combat atherosclerosis.
- Published
- 2012
- Full Text
- View/download PDF
25. Bone marrow p16INK4a-deficiency does not modulate obesity, glucose homeostasis or atherosclerosis development.
- Author
-
Wouters K, Cudejko C, Gijbels MJ, Fuentes L, Bantubungi K, Vanhoutte J, Dièvart R, Paquet C, Bouchaert E, Hannou SA, Gizard F, Tailleux A, de Winther MP, Staels B, and Paumelle R
- Subjects
- Animals, Diet, High-Fat adverse effects, Glucose Intolerance chemically induced, Glucose Intolerance metabolism, Humans, Hyperlipidemias metabolism, Hyperlipidemias pathology, Male, Mice, Mice, Inbred C57BL, Obesity chemically induced, Receptors, LDL deficiency, Atherosclerosis metabolism, Atherosclerosis pathology, Bone Marrow metabolism, Cyclin-Dependent Kinase Inhibitor p16 deficiency, Glucose metabolism, Homeostasis, Obesity metabolism
- Abstract
Objective: A genomic region near the CDKN2A locus, encoding p16(INK4a), has been associated to type 2 diabetes and atherosclerotic vascular disease, conditions in which inflammation plays an important role. Recently, we found that deficiency of p16(INK4a) results in decreased inflammatory signaling in murine macrophages and that p16(INK4a) influences the phenotype of human adipose tissue macrophages. Therefore, we investigated the influence of immune cell p16(INK4a) on glucose tolerance and atherosclerosis in mice., Methods and Results: Bone marrow p16(INK4a)-deficiency in C57Bl6 mice did not influence high fat diet-induced obesity nor plasma glucose and lipid levels. Glucose tolerance tests showed no alterations in high fat diet-induced glucose intolerance. While bone marrow p16(INK4a)-deficiency did not affect the gene expression profile of adipose tissue, hepatic expression of the alternative markers Chi3l3, Mgl2 and IL10 was increased and the induction of pro-inflammatory Nos2 was restrained on the high fat diet. Bone marrow p16(INK4a)-deficiency in low density lipoprotein receptor-deficient mice did not affect western diet-induced atherosclerotic plaque size or morphology. In line, plasma lipid levels remained unaffected and p16(INK4a)-deficient macrophages displayed equal cholesterol uptake and efflux compared to wild type macrophages., Conclusion: Bone marrow p16(INK4a)-deficiency does not affect plasma lipids, obesity, glucose tolerance or atherosclerosis in mice.
- Published
- 2012
- Full Text
- View/download PDF
26. Glutathione depletion prevents diet-induced obesity and enhances insulin sensitivity.
- Author
-
Findeisen HM, Gizard F, Zhao Y, Qing H, Jones KL, Cohn D, Heywood EB, and Bruemmer D
- Subjects
- Animals, Antioxidants metabolism, Behavior, Animal, Blood Glucose metabolism, Homeostasis, Locomotion, Mice, Mice, Inbred C57BL, Obesity etiology, Signal Transduction, Diet adverse effects, Energy Metabolism, Glutathione metabolism, Insulin Resistance, Obesity prevention & control, Reactive Oxygen Species metabolism
- Abstract
Excessive accumulation of reactive oxygen species (ROS) in adipose tissue has been implicated in the development of insulin resistance and type 2 diabetes. However, emerging evidence suggests a physiologic role of ROS in cellular signaling and insulin sensitivity. In this study, we demonstrate that pharmacologic depletion of the antioxidant glutathione in mice prevents diet-induced obesity, increases energy expenditure and locomotor activity, and enhances insulin sensitivity. These observations support a beneficial role of ROS in glucose homeostasis and warrant further research to define the regulation of metabolism and energy balance by ROS.
- Published
- 2011
- Full Text
- View/download PDF
27. Transcriptional regulation of S phase kinase-associated protein 2 by NR4A orphan nuclear receptor NOR1 in vascular smooth muscle cells.
- Author
-
Gizard F, Zhao Y, Findeisen HM, Qing H, Cohn D, Heywood EB, Jones KL, Nomiyama T, and Bruemmer D
- Subjects
- Animals, Cells, Cultured, Cyclin-Dependent Kinase Inhibitor p27 genetics, Cyclin-Dependent Kinase Inhibitor p27 metabolism, DNA-Binding Proteins genetics, Mice, Mice, Knockout, Neointima genetics, Neointima metabolism, Nerve Tissue Proteins genetics, Receptors, Steroid genetics, Receptors, Thyroid Hormone genetics, S-Phase Kinase-Associated Proteins genetics, Transcriptional Activation genetics, Cell Proliferation, DNA-Binding Proteins metabolism, Gene Expression Regulation, Enzymologic, Muscle, Smooth, Vascular metabolism, Myocytes, Smooth Muscle metabolism, Nerve Tissue Proteins metabolism, Receptors, Steroid metabolism, Receptors, Thyroid Hormone metabolism, Response Elements, S-Phase Kinase-Associated Proteins biosynthesis
- Abstract
Members of the NR4A subgroup of the nuclear hormone receptor superfamily have emerged as key transcriptional regulators of proliferation and inflammation. NOR1 constitutes a ligand-independent transcription factor of this subgroup and induces cell proliferation; however, the transcriptional mechanisms underlying this mitogenic role remain to be defined. Here, we demonstrate that the F-box protein SKP2 (S phase kinase-associated protein 2), the substrate-specific receptor of the ubiquitin ligase responsible for the degradation of p27(KIP1) through the proteasome pathway, constitutes a direct transcriptional target for NOR1. Mitogen-induced Skp2 expression is silenced in vascular smooth muscle cells (VSMC) isolated from Nor1-deficient mice or transfected with Nor1 siRNA. Conversely, adenovirus-mediated overexpression of NOR1 induces Skp2 expression in VSMC and decreases protein abundance of its target p27. Transient transfection experiments establish that NOR1 transactivates the Skp2 promoter through a nerve growth factor-induced clone B response element (NBRE). Electrophoretic mobility shift and chromatin immunoprecipitation assays further revealed that NOR1 is recruited to this NBRE site in the Skp2 promoter in response to mitogenic stimulation. In vivo Skp2 expression is increased during the proliferative response underlying neointima formation, and this transcriptional induction depends on the expression of NOR1. Finally, we demonstrate that overexpression of Skp2 rescues the proliferative arrest of Nor1-deficient VSMC. Collectively, these results characterize Skp2 as a novel NOR1-regulated target gene and detail a previously unrecognized transcriptional cascade regulating mitogen-induced VSMC proliferation.
- Published
- 2011
- Full Text
- View/download PDF
28. Oxidative stress accumulates in adipose tissue during aging and inhibits adipogenesis.
- Author
-
Findeisen HM, Pearson KJ, Gizard F, Zhao Y, Qing H, Jones KL, Cohn D, Heywood EB, de Cabo R, and Bruemmer D
- Subjects
- 3T3-L1 Cells, Adipose Tissue growth & development, Animals, Base Sequence, Body Composition, Chromatin Immunoprecipitation, DNA Primers, Glutathione metabolism, Male, Mice, Mice, Inbred C57BL, Promoter Regions, Genetic, Reverse Transcriptase Polymerase Chain Reaction, Adipose Tissue metabolism, Aging metabolism, Oxidative Stress
- Abstract
Aging constitutes a major independent risk factor for the development of type 2 diabetes and is accompanied by insulin resistance and adipose tissue dysfunction. One of the most important factors implicitly linked to aging and age-related chronic diseases is the accumulation of oxidative stress. However, the effect of increased oxidative stress on adipose tissue biology remains elusive. In this study, we demonstrate that aging in mice results in a loss of fat mass and the accumulation of oxidative stress in adipose tissue. In vitro, increased oxidative stress through glutathione depletion inhibits preadipocyte differentiation. This inhibition of adipogenesis is at least in part the result of reduced cell proliferation and an inhibition of G(1)→S-phase transition during the initial mitotic clonal expansion of the adipocyte differentiation process. While phosphorylation of the retinoblastoma protein (Rb) by cyclin/cdk complexes remains unaffected, oxidative stress decreases the expression of S-phase genes downstream of Rb. This silencing of S phase gene expression by increased oxidative stress is mediated through a transcriptional mechanism involving the inhibition of E2F recruitment and transactivation of its target promoters. Collectively, these data demonstrate a previously unrecognized role of oxidative stress in the regulation of adipogenesis which may contribute to age-associated adipose tissue dysfunction.
- Published
- 2011
- Full Text
- View/download PDF
29. Epigenetic regulation of vascular smooth muscle cell proliferation and neointima formation by histone deacetylase inhibition.
- Author
-
Findeisen HM, Gizard F, Zhao Y, Qing H, Heywood EB, Jones KL, Cohn D, and Bruemmer D
- Subjects
- Acetylation, Animals, Cell Cycle drug effects, Cell Cycle Proteins metabolism, Cells, Cultured, Chromatin Assembly and Disassembly drug effects, Cyclin D1 metabolism, Cyclin-Dependent Kinase Inhibitor p21 metabolism, Cyclin-Dependent Kinase Inhibitor p27 metabolism, Disease Models, Animal, E2F Transcription Factors metabolism, Histone Deacetylases genetics, Histones metabolism, Hyperplasia, Mice, Mice, Inbred C57BL, Muscle, Smooth, Vascular enzymology, Muscle, Smooth, Vascular injuries, Muscle, Smooth, Vascular pathology, Myocytes, Smooth Muscle enzymology, Myocytes, Smooth Muscle pathology, Phosphorylation, RNA Interference, Rats, Retinoblastoma Protein metabolism, Time Factors, Transcription, Genetic drug effects, Tunica Media enzymology, Tunica Media injuries, Tunica Media pathology, Vascular System Injuries enzymology, Vascular System Injuries pathology, Cell Proliferation drug effects, Epigenesis, Genetic drug effects, Histone Deacetylase Inhibitors pharmacology, Histone Deacetylases metabolism, Hydroxylamines pharmacology, Muscle, Smooth, Vascular drug effects, Myocytes, Smooth Muscle drug effects, Quinolines pharmacology, Tunica Media drug effects, Vascular System Injuries drug therapy
- Abstract
Objective: Proliferation of smooth muscle cells (SMC) in response to vascular injury is central to neointimal vascular remodeling. There is accumulating evidence that histone acetylation constitutes a major epigenetic modification for the transcriptional control of proliferative gene expression; however, the physiological role of histone acetylation for proliferative vascular disease remains elusive., Methods and Results: In the present study, we investigated the role of histone deacetylase (HDAC) inhibition in SMC proliferation and neointimal remodeling. We demonstrate that mitogens induce transcription of HDAC 1, 2, and 3 in SMC. Short interfering RNA-mediated knockdown of either HDAC 1, 2, or 3 and pharmacological inhibition of HDAC prevented mitogen-induced SMC proliferation. The mechanisms underlying this reduction of SMC proliferation by HDAC inhibition involve a growth arrest in the G(1) phase of the cell cycle that is due to an inhibition of retinoblastoma protein phosphorylation. HDAC inhibition resulted in a transcriptional and posttranscriptional regulation of the cyclin-dependent kinase inhibitors p21(Cip1) and p27(Kip). Furthermore, HDAC inhibition repressed mitogen-induced cyclin D1 mRNA expression and cyclin D1 promoter activity. As a result of this differential cell cycle-regulatory gene expression by HDAC inhibition, the retinoblastoma protein retains a transcriptional repression of its downstream target genes required for S phase entry. Finally, we provide evidence that these observations are applicable in vivo by demonstrating that HDAC inhibition decreased neointima formation and expression of cyclin D1 in a murine model of vascular injury., Conclusions: These findings identify HDAC as a critical component of a transcriptional cascade regulating SMC proliferation and suggest that HDAC might play a pivotal role in the development of proliferative vascular diseases, including atherosclerosis and in-stent restenosis.
- Published
- 2011
- Full Text
- View/download PDF
30. Telomerase activation in atherosclerosis and induction of telomerase reverse transcriptase expression by inflammatory stimuli in macrophages.
- Author
-
Gizard F, Heywood EB, Findeisen HM, Zhao Y, Jones KL, Cudejko C, Post GR, Staels B, and Bruemmer D
- Subjects
- Animals, Atherosclerosis pathology, Atherosclerosis physiopathology, Cells, Cultured, Coronary Vessels metabolism, Coronary Vessels pathology, Coronary Vessels physiopathology, Disease Models, Animal, Humans, Inflammation pathology, Inflammation physiopathology, Lipopolysaccharides pharmacology, Lipoproteins, LDL pharmacology, Macrophages drug effects, Macrophages pathology, Mice, Mice, Knockout, NF-kappa B metabolism, Receptors, LDL deficiency, Receptors, LDL genetics, Telomerase genetics, Tumor Necrosis Factor-alpha pharmacology, Atherosclerosis metabolism, Inflammation metabolism, Macrophages enzymology, Telomerase metabolism
- Abstract
Objective: Telomerase serves as a critical regulator of tissue renewal. Although telomerase activity is inducible in response to various environmental cues, it remains unknown whether telomerase is activated during the inflammatory remodeling underlying atherosclerosis formation. To address this question, we investigated in the present study the regulation of telomerase in macrophages and during atherosclerosis development in low-density lipoprotein receptor-deficient mice., Methods and Results: We demonstrate that inflammatory stimuli activate telomerase in macrophages by inducing the expression of the catalytic subunit telomerase reverse transcriptase (TERT). Reporter and chromatin immunoprecipitation assays identified a previously unrecognized nuclear factor-κB (NF-κB) response element in the TERT promoter, to which NF-κB is recruited during inflammation. Inhibition of NF-κB signaling completely abolished the induction of TERT expression, characterizing TERT as a bona fide NF-κB target gene. Furthermore, functional experiments revealed that TERT deficiency results in a senescent cell phenotype. Finally, we demonstrate high levels of TERT expression in macrophages of human atherosclerotic lesions and establish that telomerase is activated during atherosclerosis development in low-density lipoprotein receptor-deficient mice., Conclusions: These results characterize TERT as a previously unrecognized NF-κB target gene in macrophages and demonstrate that telomerase is activated during atherosclerosis. This induction of TERT expression prevents macrophage senescence and may have important implications for the development of atherosclerosis.
- Published
- 2011
- Full Text
- View/download PDF
31. Telomerase deficiency in bone marrow-derived cells attenuates angiotensin II-induced abdominal aortic aneurysm formation.
- Author
-
Findeisen HM, Gizard F, Zhao Y, Cohn D, Heywood EB, Jones KL, Lovett DH, Howatt DA, Daugherty A, and Bruemmer D
- Subjects
- Animals, Bone Marrow Transplantation, Cell Movement, Cells, Cultured, Elastin metabolism, Genotype, Macrophages metabolism, Macrophages pathology, Male, Matrix Metalloproteinase 2 metabolism, Mice, Mice, Knockout, Models, Animal, Receptors, LDL genetics, Receptors, LDL metabolism, Telomerase genetics, Telomere, Angiotensin II adverse effects, Aortic Aneurysm, Abdominal chemically induced, Aortic Aneurysm, Abdominal prevention & control, Macrophages enzymology, Telomerase deficiency
- Abstract
Objective: Abdominal aortic aneurysms (AAA) are an age-related vascular disease and an important cause of morbidity and mortality. In this study, we sought to determine whether the catalytic component of telomerase, telomerase reverse transcriptase (TERT), modulates angiotensin (Ang) II-induced AAA formation., Methods and Results: Low-density lipoprotein receptor-deficient (LDLr-/-) mice were lethally irradiated and reconstituted with bone marrow-derived cells from TERT-deficient (TERT-/-) mice or littermate wild-type mice. Mice were placed on a diet enriched in cholesterol, and AAA formation was quantified after 4 weeks of Ang II infusion. Repopulation of LDLr-/- mice with TERT-/- bone marrow-derived cells attenuated Ang II-induced AAA formation. TERT-deficient recipient mice revealed modest telomere attrition in circulating leukocytes at the study end point without any overt effect of the donor genotype on white blood cell counts. In mice repopulated with TERT-/- bone marrow, aortic matrix metalloproteinase-2 (MMP-2) activity was reduced, and TERT-/- macrophages exhibited decreased expression and activity of MMP-2 in response to stimulation with Ang II. Finally, we demonstrated in transient transfection studies that TERT overexpression activates the MMP-2 promoter in macrophages., Conclusions: TERT deficiency in bone marrow-derived macrophages attenuates Ang II-induced AAA formation in LDLr-/- mice and decreases MMP-2 expression. These results point to a previously unrecognized role of TERT in the pathogenesis of AAA.
- Published
- 2011
- Full Text
- View/download PDF
32. Group X secretory phospholipase A2 negatively regulates ABCA1 and ABCG1 expression and cholesterol efflux in macrophages.
- Author
-
Shridas P, Bailey WM, Gizard F, Oslund RC, Gelb MH, Bruemmer D, and Webb NR
- Subjects
- ATP Binding Cassette Transporter 1, ATP Binding Cassette Transporter, Subfamily G, Member 1, Animals, Arachidonic Acid pharmacology, Base Sequence, Biological Transport, Active drug effects, Cell Line, Female, Gene Expression drug effects, Group X Phospholipases A2 deficiency, Group X Phospholipases A2 pharmacology, Humans, Hydrocarbons, Fluorinated pharmacology, In Vitro Techniques, Liver X Receptors, Macrophages drug effects, Male, Mice, Mice, Inbred C57BL, Mice, Knockout, Orphan Nuclear Receptors agonists, Orphan Nuclear Receptors genetics, Orphan Nuclear Receptors metabolism, Prostaglandin-Endoperoxide Synthases metabolism, RNA, Messenger genetics, RNA, Messenger metabolism, RNA, Small Interfering genetics, Sulfonamides pharmacology, ATP-Binding Cassette Transporters genetics, Cholesterol metabolism, Group X Phospholipases A2 metabolism, Lipoproteins genetics, Macrophages metabolism
- Abstract
Objective: GX sPLA(2) potently hydrolyzes plasma membranes to generate lysophospholipids and free fatty acids; it has been implicated in inflammatory diseases, including atherosclerosis. To identify a novel role for group X (GX) secretory phospholipase A(2) (sPLA(2)) in modulating ATP binding casette transporter A1 (ABCA1) and ATP binding casette transporter G1 (ABCG1) expression and, therefore, macrophage cholesterol efflux., Methods and Results: The overexpression or exogenous addition of GX sPLA(2) significantly reduced ABCA1 and ABCG1 expression in J774 macrophage-like cells, whereas GX sPLA(2) deficiency in mouse peritoneal macrophages was associated with enhanced expression. Altered ABC transporter expression led to reduced cholesterol efflux in GX sPLA(2)-overexpressing J774 cells and increased efflux in GX sPLA(2)-deficient mouse peritoneal macrophages. Gene regulation was dependent on GX sPLA(2) catalytic activity, mimicked by arachidonic acid and abrogated when liver X receptor (LXR)α/β expression was suppressed, and partially reversed by the LXR agonist T0901317. Reporter assays indicated that GX sPLA(2) suppresses the ability of LXR to transactivate its promoters through a mechanism involving the C-terminal portion of LXR spanning the ligand-binding domain., Conclusions: GX sPLA(2) modulates gene expression in macrophages by generating lipolytic products that suppress LXR activation. GX sPLA(2) may play a previously unrecognized role in atherosclerotic lipid accumulation by negatively regulating the genes critical for cellular cholesterol efflux.
- Published
- 2010
- Full Text
- View/download PDF
33. Deficiency of the NR4A orphan nuclear receptor NOR1 decreases monocyte adhesion and atherosclerosis.
- Author
-
Zhao Y, Howatt DA, Gizard F, Nomiyama T, Findeisen HM, Heywood EB, Jones KL, Conneely OM, Daugherty A, and Bruemmer D
- Subjects
- Animals, Atherosclerosis pathology, Atherosclerosis prevention & control, Cell Adhesion physiology, Cells, Cultured, Coronary Vessels metabolism, Coronary Vessels pathology, DNA-Binding Proteins metabolism, Endothelium, Vascular metabolism, Endothelium, Vascular pathology, Female, Humans, Mice, Mice, Inbred C57BL, Mice, Knockout, Nuclear Receptor Subfamily 4, Group A, Member 1 metabolism, Receptors, Steroid metabolism, Receptors, Thyroid Hormone metabolism, Response Elements genetics, Vascular Cell Adhesion Molecule-1 genetics, Vascular Cell Adhesion Molecule-1 metabolism, Atherosclerosis metabolism, DNA-Binding Proteins deficiency, Monocytes physiology, Nuclear Receptor Subfamily 4, Group A, Member 1 deficiency, Receptors, Steroid deficiency, Receptors, Thyroid Hormone deficiency
- Abstract
Rationale: The orphan nuclear receptor NOR1 is a member of the evolutionary highly conserved and ligand-independent NR4A subfamily of the nuclear hormone receptor superfamily. Members of this subfamily have been characterized as early response genes regulating essential biological processes including inflammation and proliferation; however, the role of NOR1 in atherosclerosis remains unknown., Objective: The goal of the present study was to determine the causal contribution of NOR1 to atherosclerosis development and to identify the mechanism by which this nuclear receptor participates in the disease process., Methods and Results: In the present study, we demonstrate expression of NOR1 in endothelial cells of human atherosclerotic lesions. In response to inflammatory stimuli, NOR1 expression is rapidly induced in endothelial cells through a nuclear factor kappaB-dependent transactivation of the NOR1 promoter. Overexpression of NOR1 in human endothelial cells increased the expression of vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule-1, whereas NOR1 deficiency altered adhesion molecule expression in response to inflammatory stimuli. Transient transfection experiments and chromatin immunoprecipitation assays revealed that NOR1 induces VCAM-1 promoter activity by binding to a canonical response element for NR4A receptors in the VCAM-1 promoter. Further functional studies confirmed that NOR1 mediates monocyte adhesion by inducing VCAM-1 and intercellular adhesion molecule-1 expression in endothelial cells. Finally, we demonstrate that NOR1 deficiency reduces hypercholesterolemia-induced atherosclerosis formation in apoE(-/-) mice by decreasing the macrophage content of the lesion., Conclusions: In concert, these studies identify a novel pathway underlying monocyte adhesion and establish that NOR1 serves a previously unrecognized atherogenic role in mice by positively regulating monocyte recruitment to the vascular wall.
- Published
- 2010
- Full Text
- View/download PDF
34. Deficiency of the NR4A neuron-derived orphan receptor-1 attenuates neointima formation after vascular injury.
- Author
-
Nomiyama T, Zhao Y, Gizard F, Findeisen HM, Heywood EB, Jones KL, Conneely OM, and Bruemmer D
- Subjects
- Animals, Aorta cytology, Apoptosis physiology, Cell Division physiology, Cell Survival physiology, Cells, Cultured, Coronary Vessels cytology, Cyclin D1 genetics, Cyclin D2, Cyclins genetics, DNA-Binding Proteins metabolism, E2F Transcription Factors metabolism, Gene Expression physiology, Humans, Mice, Mice, Mutant Strains, Muscle, Smooth, Vascular cytology, Nuclear Receptor Subfamily 4, Group A, Member 1, Phosphorylation physiology, Promoter Regions, Genetic physiology, Rats, Receptors, Steroid metabolism, Retinoblastoma Protein metabolism, Tunica Intima cytology, Tunica Intima injuries, Tunica Intima physiology, DNA-Binding Proteins genetics, Muscle, Smooth, Vascular injuries, Muscle, Smooth, Vascular physiology, Receptors, Steroid genetics, Wound Healing physiology
- Abstract
Background: The neuron-derived orphan receptor-1 (NOR1) belongs to the evolutionary highly conserved and most ancient NR4A subfamily of the nuclear hormone receptor superfamily. Members of this subfamily function as early-response genes regulating key cellular processes, including proliferation, differentiation, and survival. Although NOR1 has previously been demonstrated to be required for smooth muscle cell proliferation in vitro, the role of this nuclear receptor for the proliferative response underlying neointima formation and target genes trans-activated by NOR1 remain to be defined., Methods and Results: Using a model of guidewire-induced arterial injury, we demonstrate decreased neointima formation in NOR1(-/-) mice compared with wild-type mice. In vitro, NOR1-deficient smooth muscle cells exhibit decreased proliferation as a result of a G(1)-->S phase arrest of the cell cycle and increased apoptosis in response to serum deprivation. NOR1 deficiency alters phosphorylation of the retinoblastoma protein by preventing mitogen-induced cyclin D1 and D2 expression. Conversely, overexpression of NOR1 induces cyclin D1 expression and the transcriptional activity of the cyclin D1 promoter in transient reporter assays. Gel shift and chromatin immunoprecipitation assays identified a putative response element for NR4A receptors in the cyclin D1 promoter, to which NOR1 is recruited in response to mitogenic stimulation. Finally, we provide evidence that these observations are applicable in vivo by demonstrating decreased cyclin D1 expression during neointima formation in NOR1-deficient mice., Conclusions: These experiments characterize cyclin D1 as an NOR1-regulated target gene in smooth muscle cells and demonstrate that NOR1 deficiency decreases neointima formation in response to vascular injury.
- Published
- 2009
- Full Text
- View/download PDF
35. The PPARalpha/p16INK4a pathway inhibits vascular smooth muscle cell proliferation by repressing cell cycle-dependent telomerase activation.
- Author
-
Gizard F, Nomiyama T, Zhao Y, Findeisen HM, Heywood EB, Jones KL, Staels B, and Bruemmer D
- Subjects
- Animals, Cells, Cultured, Cyclin-Dependent Kinase Inhibitor p16 genetics, Dyslipidemias enzymology, Dyslipidemias genetics, E2F1 Transcription Factor genetics, E2F1 Transcription Factor metabolism, Enzyme Activation drug effects, Enzyme Activation physiology, Gene Expression Regulation, Enzymologic drug effects, Mice, Mitogens metabolism, Mitogens pharmacology, PPAR alpha agonists, Promoter Regions, Genetic physiology, Rats, Retinoblastoma-Like Protein p107 genetics, Retinoblastoma-Like Protein p107 metabolism, Retinoblastoma-Like Protein p130 genetics, Retinoblastoma-Like Protein p130 metabolism, Telomerase genetics, Transcription, Genetic drug effects, Transcription, Genetic physiology, Cyclin-Dependent Kinase Inhibitor p16 metabolism, G1 Phase physiology, Gene Expression Regulation, Enzymologic physiology, Myocytes, Smooth Muscle enzymology, PPAR alpha metabolism, S Phase physiology, Telomerase biosynthesis
- Abstract
Peroxisome proliferator-activated receptor (PPAR)alpha, the molecular target for fibrates used to treat dyslipidemia, exerts pleiotropic effects on vascular cells. In vascular smooth muscle cells (VSMCs), we have previously demonstrated that PPARalpha activation suppresses G(1)-->S cell cycle progression by targeting the cyclin-dependent kinase inhibitor p16(INK4a) (p16). In the present study, we demonstrate that this inhibition of VSMC proliferation by PPARalpha is mediated through a p16-dependent suppression of telomerase activity, which has been implicated in key cellular functions including proliferation. PPARalpha activation inhibited mitogen-induced telomerase activity by repressing the catalytic subunit telomerase reverse transcriptase (TERT) through negative cross-talk with an E2F-1-dependent trans-activation of the TERT promoter. This trans-repression involved the recruitment of the retinoblastoma (RB) family proteins p107 and p130 to the TERT promoter resulting in impaired E2F-1 binding, an effect that was dependent on p16. The inhibition of cell proliferation by PPARalpha activation was lost in VSMCs following TERT overexpression or knockdown, pointing to a key role of telomerase as a target for the antiproliferative effects of PPARalpha. Finally, we demonstrate that PPARalpha agonists suppress telomerase activation during the proliferative response following vascular injury, indicating that these findings are applicable in vivo. In concert, these results demonstrate that the antiproliferative effects of PPARalpha in VSMCs depend on the suppression of telomerase activity by targeting the p16/RB/E2F transcriptional cascade.
- Published
- 2008
- Full Text
- View/download PDF
36. Transcriptional Control of Vascular Smooth Muscle Cell Proliferation by Peroxisome Proliferator-Activated Receptor-gamma: Therapeutic Implications for Cardiovascular Diseases.
- Author
-
Gizard F and Bruemmer D
- Abstract
Proliferation of vascular smooth muscle cells (SMCs) is a critical process for the development of atherosclerosis and complications of procedures used to treat atherosclerotic diseases, including postangioplasty restenosis, vein graft failure, and transplant vasculopathy. Peroxisome proliferator-activated receptor (PPAR) gamma is a member of the nuclear hormone receptor superfamily and the molecular target for the thiazolidinediones (TZD), used clinically to treat insulin resistance in patients with type 2 diabetes. In addition to their efficacy to improve insulin sensitivity, TZD exert a broad spectrum of pleiotropic beneficial effects on vascular gene expression programs. In SMCs, PPARgamma is prominently upregulated during neointima formation and suppresses the proliferative response to injury of the arterial wall. Among the molecular target genes regulated by PPARgamma in SMCs are genes encoding proteins involved in the regulation of cell-cycle progression, cellular senescence, and apoptosis. This inhibition of SMC proliferation is likely to contribute to the prevention of atherosclerosis and postangioplasty restenosis observed in animal models and proof-of-concept clinical studies. This review will summarize the transcriptional target genes regulated by PPARgamma in SMCs and outline the therapeutic implications of PPARgamma activation for the treatment and prevention of atherosclerosis and its complications.
- Published
- 2008
- Full Text
- View/download PDF
37. Osteopontin mediates obesity-induced adipose tissue macrophage infiltration and insulin resistance in mice.
- Author
-
Nomiyama T, Perez-Tilve D, Ogawa D, Gizard F, Zhao Y, Heywood EB, Jones KL, Kawamori R, Cassis LA, Tschöp MH, and Bruemmer D
- Subjects
- Animals, Chemokine CCL2 metabolism, Chemotaxis genetics, Dietary Fats administration & dosage, Inflammation genetics, Inflammation immunology, Mice, Mice, Mutant Strains, Obesity complications, Osteopontin genetics, Adipose Tissue immunology, Insulin Resistance immunology, Macrophages immunology, Obesity immunology, Osteopontin physiology
- Abstract
Obesity is associated with a state of chronic, low-grade inflammation characterized by abnormal cytokine production and macrophage infiltration into adipose tissue, which may contribute to the development of insulin resistance. During immune responses, tissue infiltration by macrophages is dependent on the expression of osteopontin, an extracellular matrix protein and proinflammatory cytokine that promotes monocyte chemotaxis and cell motility. In the present study, we used a murine model of diet-induced obesity to examine the role of osteopontin in the accumulation of adipose tissue macrophages and the development of insulin resistance during obesity. Mice exposed to a high-fat diet exhibited increased plasma osteopontin levels, with elevated expression in macrophages recruited into adipose tissue. Obese mice lacking osteopontin displayed improved insulin sensitivity in the absence of an effect on diet-induced obesity, body composition, or energy expenditure. These mice further demonstrated decreased macrophage infiltration into adipose tissue, which may reflect both impaired macrophage motility and attenuated monocyte recruitment by stromal vascular cells. Finally, obese osteopontin-deficient mice exhibited decreased markers of inflammation, both in adipose tissue and systemically. Taken together, these results suggest that osteopontin may play a key role in linking obesity to the development of insulin resistance by promoting inflammation and the accumulation of macrophages in adipose tissue.
- Published
- 2007
- Full Text
- View/download PDF
38. The NR4A orphan nuclear receptor NOR1 is induced by platelet-derived growth factor and mediates vascular smooth muscle cell proliferation.
- Author
-
Nomiyama T, Nakamachi T, Gizard F, Heywood EB, Jones KL, Ohkura N, Kawamori R, Conneely OM, and Bruemmer D
- Subjects
- Animals, Atherosclerosis metabolism, Cell Proliferation, Cells, Cultured, Cyclic AMP Response Element-Binding Protein genetics, Cyclic AMP Response Element-Binding Protein metabolism, DNA-Binding Proteins genetics, Gene Expression Regulation, Humans, MAP Kinase Signaling System, Mitogen-Activated Protein Kinases metabolism, Molecular Sequence Data, Muscle, Smooth, Vascular cytology, Myocytes, Smooth Muscle cytology, Nerve Tissue Proteins genetics, Phosphoserine metabolism, Promoter Regions, Genetic genetics, Protein Binding, RNA, Messenger genetics, Rats, Receptors, Steroid genetics, Receptors, Thyroid Hormone genetics, Response Elements, Transcription, Genetic genetics, Transcriptional Activation genetics, DNA-Binding Proteins metabolism, Muscle, Smooth, Vascular drug effects, Muscle, Smooth, Vascular metabolism, Myocytes, Smooth Muscle drug effects, Myocytes, Smooth Muscle metabolism, Nerve Tissue Proteins metabolism, Platelet-Derived Growth Factor pharmacology, Receptors, Steroid metabolism, Receptors, Thyroid Hormone metabolism
- Abstract
Members of the nuclear hormone receptor superfamily function as key transcriptional regulators of inflammation and proliferation in cardiovascular diseases. In addition to the ligand-dependent peroxisome proliferator-activated receptors and liver X receptors, this family of transcription factors includes a large number of orphan receptors, and their role in vascular diseases remains to be investigated. The neuron-derived orphan receptor-1 (NOR1) belongs to the ligand-independent NR4A subfamily, which has been implicated in cell proliferation, differentiation, and apoptosis. In this study, we demonstrate NOR1 expression in vascular smooth muscle cells (SMC) of human atherosclerotic lesions. In response to mitogenic stimulation with platelet-derived growth factor (PDGF), SMC rapidly express NOR1 through an ERK-MAPK-dependent signaling pathway. 5'-deletion analysis, site-directed mutagenesis, and transactivation experiments demonstrate that PDGF-induced NOR1 expression is mediated through a cAMP-response element-binding protein (CREB)-dependent transactivation of the NOR1 promoter. Consequently, short interfering RNA-mediated depletion of CREB abolished PDGF-induced NOR1 expression in SMC. Furthermore, PDGF induced Ser-133 phosphorylation of CREB and subsequent binding to the CRE sites of the endogenous NOR1 promoter. Functional analysis demonstrated that PDGF induces NOR1 transactivation of its consensus NGFI-B-response elements (NBRE) in SMC. We finally demonstrate that SMC isolated from NOR1-deficient mice exhibit decreased cell proliferation and characterize cyclin D1 and D2 as NOR1 target genes in SMC. These experiments indicate that PDGF-induced NOR1 transcription in SMC is mediated through CREB-dependent transactivation of the NOR1 promoter and further demonstrate that NOR1 functions as a key transcriptional regulator of SMC proliferation.
- Published
- 2006
- Full Text
- View/download PDF
39. TReP-132 is a novel progesterone receptor coactivator required for the inhibition of breast cancer cell growth and enhancement of differentiation by progesterone.
- Author
-
Gizard F, Robillard R, Gross B, Barbier O, Révillion F, Peyrat JP, Torpier G, Hum DW, and Staels B
- Subjects
- Binding Sites, Breast Neoplasms genetics, Cell Cycle drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Cyclin-Dependent Kinase Inhibitor p21 genetics, Cyclin-Dependent Kinase Inhibitor p21 metabolism, Cyclin-Dependent Kinase Inhibitor p27 genetics, Cyclin-Dependent Kinase Inhibitor p27 metabolism, DNA-Binding Proteins genetics, Gene Expression Regulation, Neoplastic, Humans, Promoter Regions, Genetic genetics, RNA, Small Interfering genetics, Receptors, Progesterone genetics, Transcription Factors genetics, Breast Neoplasms metabolism, Breast Neoplasms pathology, Cell Differentiation drug effects, DNA-Binding Proteins metabolism, Progesterone pharmacology, Receptors, Progesterone metabolism, Transcription Factors metabolism
- Abstract
The sex steroid progesterone is essential for the proliferation and differentiation of the mammary gland epithelium during pregnancy. In relation to this, in vitro studies using breast carcinoma T47D cells have demonstrated a biphasic progesterone response, consisting of an initial proliferative burst followed by a sustained growth arrest. However, the transcriptional factors acting with the progesterone receptor (PR) to mediate the progesterone effects on mammary cell growth and differentiation remain to be determined. Recently, it has been demonstrated that the transcriptional regulating protein of 132 kDa (TReP-132), initially identified as a regulator of steroidogenesis, is also a cell growth suppressor. Similar to progesterone-bound PR, TReP-132 acts by inducing the gene expression of the G1 cyclin-dependent kinase inhibitors p21WAF1/Cip1 (p21) and p27Kip1 (p27). The putative interaction between TReP-132 and progesterone pathways in mammary cells was therefore analyzed in the present study. Our results show that TReP-132 interacts in vitro and in T47D cells with progesterone-activated PR. TReP-132 synergizes with progesterone-bound PR to trans activate the p21 and p27 gene promoters at proximal Sp1-binding sites. Moreover, TReP-132 overexpression and knockdown, respectively, increased or prevented the induction of p21 and p27 gene expression by progesterone. As a consequence, TReP-132 knockdown also resulted in the loss of the inhibitory effects of progesterone on pRB phosphorylation, G1/S cell cycle progression, and cell proliferation. Furthermore, the knockdown of TReP-132 expression also prevented the induction of both early and terminal markers of breast cell differentiation which had been previously identified as progesterone target genes. As well, the progesterone-induced accumulation of lipid vacuoles was inhibited in the TReP-132-depleted cells. Finally, TReP-132 gene expression levels increased following progesterone treatment, indicating the existence of a positive auto-regulatory loop between PR and TReP-132. Taken together, these data identify TReP-132 as a coactivator of PR mediating the growth-inhibitory and differentiation effects of progesterone on breast cancer cells.
- Published
- 2006
- Full Text
- View/download PDF
40. [The fibrate-activated PPARalpha/p16INK4A pathway inhibits vascular smooth muscle cell proliferation and vascular occlusion].
- Author
-
Gizard F and Staels B
- Subjects
- Animals, Arteriosclerosis physiopathology, Cell Division, Cholesterol metabolism, Clofibric Acid therapeutic use, Coronary Restenosis prevention & control, Gene Expression Regulation drug effects, Genes, p16, Humans, Hyperplasia, Mice, Mice, Knockout, Models, Cardiovascular, Signal Transduction drug effects, Tunica Intima drug effects, Tunica Intima pathology, Vasculitis complications, Arteriosclerosis prevention & control, Clofibric Acid pharmacology, Cyclin-Dependent Kinase Inhibitor p16 physiology, Muscle, Smooth, Vascular cytology, Myocytes, Smooth Muscle cytology, PPAR alpha physiology
- Published
- 2006
- Full Text
- View/download PDF
41. Effect of rosiglitazone treatment on plaque inflammation and collagen content in nondiabetic patients: data from a randomized placebo-controlled trial.
- Author
-
Meisner F, Walcher D, Gizard F, Kapfer X, Huber R, Noak A, Sunder-Plassmann L, Bach H, Haug C, Bachem M, Stojakovic T, März W, Hombach V, Koenig W, Staels B, and Marx N
- Subjects
- Aged, Blood Glucose drug effects, Body Mass Index, C-Reactive Protein metabolism, Carotid Stenosis metabolism, Carotid Stenosis physiopathology, Cholesterol blood, Cholesterol, HDL blood, Cholesterol, LDL blood, Diabetes Mellitus, Female, Humans, Hypoglycemic Agents therapeutic use, Inflammation drug therapy, Insulin blood, Male, Middle Aged, Rosiglitazone, Serum Amyloid A Protein metabolism, Thiazolidinediones therapeutic use, Carotid Stenosis drug therapy, Collagen metabolism, Hypoglycemic Agents administration & dosage, Thiazolidinediones administration & dosage
- Abstract
Background: Therapeutic strategies to stabilize advanced arteriosclerotic lesions may prevent plaque rupture and reduce the incidence of acute coronary syndromes. Thiazolidinediones (TZDs), like rosiglitazone, are oral antidiabetic drugs with additional antiinflammatory and potential antiatherogenic properties. In a randomized, placebo-controlled, single-blind trial, we examined the effect of 4 weeks of rosiglitazone therapy on histomorphological characteristics of plaque stability in artery specimen of nondiabetic patients scheduled for elective carotid endarterectomy., Methods and Results: A total of 24 nondiabetic patients with symptomatic carotid artery stenosis were randomly assigned to rosiglitazone (4 mg BID) or placebo in addition to standard therapy. In this population of nondiabetic patients, rosiglitazone treatment did not significantly change fasting blood glucose, fasting insulin, or lipid parameters. In contrast, rosiglitazone significantly reduced CD4-lymphocyte content as well as macrophage HLA-DR expression in the shoulder region, reflecting less inflammatory activation of these cells by lymphocyte interferon-gamma. Moreover, rosiglitazone significantly increased plaque collagen content (7.7+/-1.6% versus 3.7+/-0.7% of plaque area; P=0.036) compared with placebo, suggesting that TZD treatment may stabilize arteriosclerotic lesions. In addition, rosiglitazone reduced serum levels of 2 inflammatory arteriosclerosis markers: C-reactive protein and serum amyloid A., Conclusions: Four weeks of treatment with rosiglitazone significantly reduces vascular inflammation in nondiabetic patients, leading to a more stable type of arteriosclerotic lesion.
- Published
- 2006
- Full Text
- View/download PDF
42. PPAR alpha inhibits vascular smooth muscle cell proliferation underlying intimal hyperplasia by inducing the tumor suppressor p16INK4a.
- Author
-
Gizard F, Amant C, Barbier O, Bellosta S, Robillard R, Percevault F, Sevestre H, Krimpenfort P, Corsini A, Rochette J, Glineur C, Fruchart JC, Torpier G, and Staels B
- Subjects
- Animals, Carotid Artery Injuries genetics, Carotid Artery Injuries metabolism, Carotid Artery Injuries pathology, Cells, Cultured, Cyclin-Dependent Kinase 4 physiology, Cyclin-Dependent Kinase Inhibitor p16 deficiency, Cyclin-Dependent Kinase Inhibitor p16 genetics, Cyclin-Dependent Kinase Inhibitor p16 physiology, Down-Regulation genetics, G1 Phase genetics, Growth Inhibitors deficiency, Growth Inhibitors genetics, HeLa Cells, Humans, Hyperplasia, Mice, Mice, Inbred C57BL, Mice, Knockout, Myocytes, Smooth Muscle metabolism, Myocytes, Smooth Muscle pathology, PPAR alpha deficiency, PPAR alpha genetics, Phosphorylation, Retinoblastoma Protein metabolism, S Phase genetics, Transcription, Genetic physiology, Tunica Intima cytology, Cell Proliferation, Cyclin-Dependent Kinase Inhibitor p16 biosynthesis, Growth Inhibitors physiology, Muscle, Smooth, Vascular pathology, PPAR alpha physiology, Tunica Intima pathology, Up-Regulation genetics
- Abstract
Vascular SMC proliferation is a crucial event in occlusive cardiovascular diseases. PPARalpha is a nuclear receptor controlling lipid metabolism and inflammation, but its role in the regulation of SMC growth remains to be established. Here, we show that PPARalpha controls SMC cell-cycle progression at the G1/S transition by targeting the cyclin-dependent kinase inhibitor and tumor suppressor p16(INK4a) (p16), resulting in an inhibition of retinoblastoma protein phosphorylation. PPARalpha activates p16 gene transcription by both binding to a canonical PPAR-response element and interacting with the transcription factor Sp1 at specific proximal Sp1-binding sites of the p16 promoter. In a carotid arterial-injury mouse model, p16 deficiency results in an enhanced SMC proliferation underlying intimal hyperplasia. Moreover, PPARalpha activation inhibits SMC growth in vivo, and this effect requires p16 expression. These results identify an unexpected role for p16 in SMC cell-cycle control and demonstrate that PPARalpha inhibits SMC proliferation through p16. Thus, the PPARalpha/p16 pathway may be a potential pharmacological target for the prevention of cardiovascular occlusive complications of atherosclerosis.
- Published
- 2005
- Full Text
- View/download PDF
43. Progesterone inhibits human breast cancer cell growth through transcriptional upregulation of the cyclin-dependent kinase inhibitor p27Kip1 gene.
- Author
-
Gizard F, Robillard R, Gervois P, Faucompré A, Révillion F, Peyrat JP, Hum WD, and Staels B
- Subjects
- Breast Neoplasms genetics, Cell Cycle drug effects, Cell Line, Tumor, Cell Proliferation drug effects, Cyclin-Dependent Kinase Inhibitor p27 biosynthesis, Humans, Progesterone pharmacology, Promoter Regions, Genetic, Sp1 Transcription Factor metabolism, Up-Regulation, Breast Neoplasms drug therapy, Cyclin-Dependent Kinase Inhibitor p27 genetics, Intracellular Signaling Peptides and Proteins genetics, Progesterone therapeutic use, Receptors, Progesterone metabolism, Transcription, Genetic drug effects
- Abstract
The effects of progesterone derivatives on breast cancer development are still controversial, probably accounting for their biphasic, opposed effects on mammary cell-cycle regulation. Here, we demonstrate in vitro that the growth-inhibitory effects of progesterone on breast cancer T-47D cells require the transcriptional upregulation of the cyclin-dependent kinase inhibitor p27(Kip1) (p27) gene. A statistical analysis of human tumor biopsies further indicates that p27 mRNA levels correlate to progesterone receptor (PR) levels. Moreover, p27 gene expression is inversely associated with tumor aggressiveness, and is a prognostic factor of favorable disease outcome. Thus, progesterone derivatives selectively activating the p27 gene promoter could be promising drugs against breast cancer progression.
- Published
- 2005
- Full Text
- View/download PDF
44. TReP-132 controls cell proliferation by regulating the expression of the cyclin-dependent kinase inhibitors p21WAF1/Cip1 and p27Kip1.
- Author
-
Gizard F, Robillard R, Barbier O, Quatannens B, Faucompré A, Révillion F, Peyrat JP, Staels B, and Hum DW
- Subjects
- Breast Neoplasms genetics, Breast Neoplasms metabolism, Cell Proliferation, Cyclin-Dependent Kinase Inhibitor p21, Cyclin-Dependent Kinase Inhibitor p27, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Female, Gene Expression Regulation, Gene Silencing, HeLa Cells, Humans, Promoter Regions, Genetic, RNA, Messenger analysis, RNA, Messenger metabolism, RNA, Small Interfering genetics, Steroidogenic Factor 1, Transcription Factors genetics, Transcription Factors metabolism, Cell Cycle physiology, Cell Cycle Proteins genetics, DNA-Binding Proteins physiology, Sp1 Transcription Factor metabolism, Transcription Factors physiology, Tumor Suppressor Proteins genetics
- Abstract
The transcriptional regulating protein of 132 kDa (TReP-132) has been identified in steroidogenic tissues, where it acts as a coactivator of steroidogenic factor 1 (SF-1). We show here that TReP-132 plays a role in the control of cell proliferation. In human HeLa cells, TReP-132 knockdown by using small interfering RNA resulted in increased G(1)-->S cell cycle progression. The growth-inhibitory effects of TReP-132 was further shown to be mediated by induction of G(1) cyclin-dependent kinase inhibitors p21(WAF1) (p21) and p27(KIP1) (p27) expression levels. As a consequence, G(1) cyclin/cyclin-dependent kinase activities and pRB phosphorylation were markedly reduced, and cell cycle progression was blocked in the G(1) phase. The stimulatory effect of TReP-132 on p21 and p27 gene transcription involved interaction of TReP-132 with the transcription factor Sp1 at proximal Sp1-binding sites in their promoters. Moreover, in different breast tumor cell lines, endogenous TReP-132 expression was positively related with a lower proliferation rate. In addition, TReP-132 knockdown resulted in enhanced cell proliferation and lowered p21 and p27 mRNA levels in the steroid-responsive and nonresponsive T-47D and MDA-MB-231 cell lines, respectively. Finally, a statistic profiling of human breast tumor samples highlighted that expression of TReP-132 is correlated with p21 and p27 levels and is associated with lower tumor incidence and aggressiveness. Together, these results identify TReP-132 as a basal cell cycle regulatory protein acting, at least in part, by interacting with Sp1 to activate the p21 and p27 gene promoters.
- Published
- 2005
- Full Text
- View/download PDF
45. [A role of PPARgamma in reproduction?].
- Author
-
Froment P, Gizard F, Staels B, Dupont J, and Monget P
- Subjects
- Animals, Embryonic Development, Female, Humans, Male, Polycystic Ovary Syndrome drug therapy, Thiazolidinediones therapeutic use, PPAR gamma physiology, Reproduction physiology
- Abstract
Synthetic molecules of the glitazone family are currently used in the treatment of type II diabetes. Glitazones also improve secondary pathologies that are frequently associated with insulin resistance such as the polycystic ovary syndrome (PCOS). Glitazones bind to the peroxysome proliferator-activated receptor gamma (PPARgamma), a nuclear receptor which is highly expressed in adipose tissue. PPARgamma also binds natural ligands such as long-chain fatty acids. Recently, several groups have shown that PPARgamma is also highly expressed in ovarian granulosa cells, and that glitazones are able to modulate in vitro granulosa cell proliferation and steroidogenesis in several species. These recent data raise new questions concerning the underlying mechanism of the effect of glitazones on PCOS. One might hypothesize, as for other << glucophage >> molecules such as metformin, that it is the general improvement of glucose metabolism and insulin sensitivity by glitazones which indirectly, and via an unknown mechanism, ameliorates ovarian functionality. The data discussed here suggest now an alternative possibility, that glitazones act directly at the ovarian level. Moreover, PPARgamma also seems to play a key role in the maturation of the placenta. In particular, inactivation of PPARgamma in mice is lethal, since the foetus is unable to develop because of alterations of placental maturation. In women, the activation of PPARgamma in placenta leads to an increase of placental hormone secretion. Overall, these results raise some questions about the role of natural ligands of PPARgamma such as long chain fatty acids on female fertility and the interactions between energy metabolism and reproduction in general.
- Published
- 2005
- Full Text
- View/download PDF
46. Function of the transcriptional regulating protein of 132 kDa (TReP-132) on human P450scc gene expression.
- Author
-
Gizard F, El-Alfy M, Duguay Y, Lavallée B, DeWitte F, Staels B, Beatty BG, and Hum DW
- Subjects
- DNA-Binding Proteins genetics, Humans, Male, Prostate cytology, Prostate metabolism, Protein Isoforms genetics, Protein Isoforms physiology, RNA, Messenger metabolism, Steroidogenic Factor 1, Tissue Distribution, Transcription Factors genetics, Transcription, Genetic physiology, Tumor Cells, Cultured, Cholesterol Side-Chain Cleavage Enzyme genetics, DNA-Binding Proteins physiology, Gene Expression Regulation physiology, Transcription Factors physiology
- Abstract
Cytochrome P450scc catalyzes the important first step in the steroid synthesis pathway; however, it is clear that additional factors regulating the temporal and spacial specific expression of the CYP11A1 gene remain to be identified. To isolate novel transcription factors that regulate this gene, a cis-acting element of the 5'-flanking region from nucleotides -155 to -131 (-155/-131) was used to screen a human placental lambda gt11 cDNA expression library, and an interacting clone was isolated. The open reading frame of the cDNA encodes several domains that are characteristic of transcription factors including an acidic region, a region rich in prolines and three zinc-finger motifs. Expression of the cDNA by in vitro transcription/translation and by transient transfection in HeLa cells yielded a protein of 132 kDa, which concurs with the predicted size. Transfection of the cDNA in placental JEG-3 and adrenal NCI-H295 cells, stimulate expression of a reporter construct controlled by the P450scc gene 5'-flanking region from nucleotides -1676 to +49. This transcriptional regulating protein of 132kDa (TReP-132) when expressed in HeLa cells was demonstrated to interact with the -155/-131 region in bandshift analysis, and tandem copies of this region was shown to confer activation of the heterologous HSV thymidine kinase minimal promoter. Coexpression of CBP/p300 with TReP-132 further increased promoter activity, and the proteins were demonstrated to interact physically. RNA analysis demonstrated the highest levels of expression in the adrenal cortex and testis; and transcript expression is also found in the steroidogenic JEG-3, NCI-H295, and MCF-7 cell lines, but not in non-steroidogenic HepG2 and HK293 cells. Subsequently it has been shown that TReP-132 interacts with steroidogenic factor-1 (SF-1) through specific domains; and along with the interaction with CBP/p300 these factors are postulated to form a complex to regulate expression of the P450scc gene.
- Published
- 2002
- Full Text
- View/download PDF
47. The transcriptional regulating protein of 132 kDa (TReP-132) enhances P450scc gene transcription through interaction with steroidogenic factor-1 in human adrenal cells.
- Author
-
Gizard F, Lavallee B, DeWitte F, Teissier E, Staels B, and Hum DW
- Subjects
- Adrenal Gland Neoplasms metabolism, Amino Acid Motifs, Animals, Blotting, Western, Cholesterol Side-Chain Cleavage Enzyme genetics, Chromatography, High Pressure Liquid, DNA, Complementary metabolism, E1A-Associated p300 Protein, Fushi Tarazu Transcription Factors, Glutathione Transferase metabolism, Homeodomain Proteins, Humans, Luciferases metabolism, Mice, Models, Genetic, Nuclear Proteins metabolism, Plasmids metabolism, Precipitin Tests, Pregnenolone metabolism, Promoter Regions, Genetic, Protein Binding, Protein Structure, Tertiary, Receptors, Cytoplasmic and Nuclear, Steroidogenic Factor 1, Time Factors, Trans-Activators metabolism, Transfection, Tumor Cells, Cultured, Adrenal Glands cytology, Cholesterol Side-Chain Cleavage Enzyme metabolism, DNA-Binding Proteins metabolism, DNA-Binding Proteins physiology, Transcription Factors metabolism, Transcription Factors physiology, Transcription, Genetic
- Abstract
The human P450scc gene is regulated by the tissue-specific orphan nuclear receptor, steroidogenic factor-1 (SF-1), which plays a key role in several physiologic processes including steroid synthesis, adrenal and gonadal development, and sexual differentiation. Several studies have demonstrated the interaction of SF-1 with different proteins. However, it is clear that additional factors not yet identified are involved with SF-1 to regulate different target genes. Recently, it was demonstrated that a novel transcriptional regulating protein of 132 kDa (TReP-132) regulates expression of the human P450scc gene. The overexpression of TReP-132 in adrenal cells increases the production of pregnenolone, which is associated with the activation of P450scc gene expression. Considering the colocalization of TReP-132 and SF-1 in steroidogenic tissues such as the adrenal and testis, and the presence of two putative LXXLL motifs in TReP-132 that can potentially interact with SF-1, the relationship between these two factors on the P450scc gene promoter was determined. The coexpression of SF-1 and TReP-132 in adrenal NCI-H295 cells cooperates to increase promoter activity. Pull-down experiments demonstrated the interaction between TReP-132 and SF-1, and this was further confirmed in intact cells by coimmunoprecipitation/Western blot and two-hybrid analyses. Deletions and mutations of the TReP-132 cDNA sequence demonstrate that SF-1 interaction requires the LXXLL motif found at the amino-terminal region of the protein. Also, the "proximal activation domain" and the "AF-2 hexamer" motif of SF-1 are involved in interaction with TReP-132. Consistent with previous studies showing interaction between CBP/p300 and SF-1 or TReP-132, the coexpression of these three proteins results in a synergistic effect on P450scc gene promoter activity. Taken together the results in this study identify a novel function of TReP-132 as a partner in a complex with SF-1 and CBP/p300 to regulate gene transcription involved in steroidogenesis.
- Published
- 2002
- Full Text
- View/download PDF
48. A novel zinc finger protein TReP-132 interacts with CBP/p300 to regulate human CYP11A1 gene expression.
- Author
-
Gizard F, Lavallée B, DeWitte F, and Hum DW
- Subjects
- Adrenal Cortex metabolism, Amino Acid Sequence, Base Sequence, Binding Sites, Blotting, Northern, Blotting, Western, Cell Line, Cell Nucleus metabolism, DNA, Complementary metabolism, Gene Library, HeLa Cells, Humans, Immunohistochemistry, Male, Microscopy, Fluorescence, Molecular Sequence Data, Placenta metabolism, Plasmids metabolism, Precipitin Tests, Promoter Regions, Genetic, Protein Binding, Protein Structure, Tertiary, Ribonucleases metabolism, Steroids metabolism, Testis metabolism, Thymus Gland metabolism, Tissue Distribution, Transfection, Tumor Cells, Cultured, Cholesterol Side-Chain Cleavage Enzyme biosynthesis, Cholesterol Side-Chain Cleavage Enzyme genetics, DNA-Binding Proteins chemistry, DNA-Binding Proteins physiology, Gene Expression Regulation, Enzymologic, Nuclear Proteins chemistry, Nuclear Proteins metabolism, Trans-Activators chemistry, Trans-Activators metabolism, Transcription Factors chemistry, Transcription Factors physiology, Zinc Fingers
- Abstract
The human CYP11A1 gene is expressed specifically in steroidogenic tissues and encodes cytochrome P450scc, which catalyzes the first step in steroid synthesis. A region of the 5'-flanking DNA of the gene from nucleotides -155 to -131 (-155/-131) is shown to activate transcription in steroidogenic human placental JEG-3 (1) and adrenal NCI-H295 cells. Using this region of the gene as probe, a cDNA clone of 4.4 kilobase pairs was isolated by screening JEG-3 cell and human placental cDNA expression libraries. The open reading frame encodes three zinc fingers of the C(2)H(2) subtype, and separate regions rich in glutamate, proline, and glutamine, which are indicative of a DNA-binding protein involved in gene transcription. Expression of the cDNA in vitro and in HeLa cells yields a protein of 132 kDa, which concurs with the predicted size. Northern blot analysis demonstrate expression of two TReP-132 transcripts of 4.4 and 7.5 kilobase pairs in the thymus, adrenal cortex, and testis; and expression is also found in the steroidogenic JEG-3, NCI-H295, and MCF-7 cell lines. Immunocytochemistry analysis demonstrates localization of the HA-tagged TReP-132 protein in the nucleus. The expression of exogenous TReP-132 in HeLa cells was demonstrated to interact with the -155/-131 region in bandshift analysis. Transfection of the cDNA in placental JEG-3 and adrenal NCI-H295 cells increases expression of a reporter construct controlled by the P450scc gene 5'-flanking region from nucleotides -1676 to +49. Moreover, a chimeric protein generated by fusion of TReP-132 with the Gal4 DNA-binding domain was able to significantly increase promoter activity of a reporter construct via Gal4-binding sites upstream of the E1b minimal promoter. Coexpression of CREB-binding protein (CBP)/p300 with TReP-132 has an additive effect on promoter activity, and the proteins were demonstrated to interact physically. Thus, these results together indicate the isolation of a novel zinc-finger transcriptional regulating protein of 132 kDa (TReP-132) involved in the regulation of P450scc gene expression.
- Published
- 2001
- Full Text
- View/download PDF
49. Role of nitric oxide in pentylenetetrazol-induced seizures: age-dependent effects in the immature rat.
- Author
-
de Vasconcelos AP, Gizard F, Marescaux C, and Nehlig A
- Subjects
- Age Factors, Animals, Animals, Newborn growth & development, Arginine pharmacology, Catalysis, Disease Models, Animal, Electroencephalography statistics & numerical data, Epilepsy mortality, Female, Male, NG-Nitroarginine Methyl Ester pharmacology, Nitric Oxide antagonists & inhibitors, Rats, Rats, Sprague-Dawley, Brain growth & development, Brain physiopathology, Epilepsy chemically induced, Epilepsy physiopathology, Nitric Oxide physiology, Pentylenetetrazole
- Abstract
Purpose: Seizure susceptibility and consequences are highly age dependent. To understand the pathophysiologic mechanisms involved in seizures and their consequences during development, we investigated the role of nitric oxide (NO) in severe pentylenetetrazol (PTZ)-induced seizures in immature rats., Methods: Four cortical electrodes were implanted in 10-day-old (P10) and 21-day-old (P21) rats, and seizures were induced on the following day by repetitive injections of subconvulsive doses of PTZ. The effects of NG-nitro-l-arginine methyl ester (l-NAME; 10 mg/kg) and 7-nitroindazole (7NI; 40 mg/kg), two NO synthase (NOS) inhibitors, and l-arginine (l-arg; 300 mg/kg), the NOS substrate, were evaluated regarding the mean PTZ dose, seizure type and duration, and mortality rate., Results: At P10, the postseizure mortality rate increased from 18-29% for the rats receiving PTZ only to 100% and 89% for the rats receiving l-NAME and 7NI, respectively; whereas l-arg had no effect. Conversely, at P21, NOS inhibitors did not affect the 82-89% mortality rate induced by PTZ alone, whereas l-arg decreased the mortality rate to 29%. In addition, all NO-related drugs increased the duration of ictal activity at P10, whereas at P21, l-arg and l-NAME affected the first seizure type, producing clonic seizures with l-arg and tonic seizures with l-NAME., Conclusions: The relative natural protection of very immature rats (P10) against PTZ-induced deaths could be linked to a high availability of l-arg and, hence, endogenous NO. At P21, the modulation of seizure type by NO-related compounds may be related to the maturation of the brain circuitry, in particular the forebrain, which is involved in the expression of clonic seizures.
- Published
- 2000
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.