Search

Prenatal adipose tissue development affects body composition and growth trajectory in early infancy, therefore it is a key determinant of adiposity in childhood. Childhood overweight and obesity increase the probability of being obese as an adult. After birth and in adulthood, adipose tissue macrophages (ATMs) are relevant constituents of the fat depots, and they are necessary for physiological adipose tissue development and fat metabolism. In obesity, however, ATMs may induce chronic inflammation leading to insulin resistance, pancreatic beta cell damage and self-immunity. Despite being relevant regulators of adipose tissue development and functioning, it is unknown whether ATMs are present in the fetal adipose tissue, therefore it is elusive whether they may affect the prenatal establishment of fat depots. Here we studied the distribution of ATMs in the human fetus between gestational weeks 17 and 38 and labeled ATMs in the early postnatal life. We found that CD45+/CD14+/CD68+ ATMs infiltrated the fetal adipose tissue from the 17th week of gestation and remained persistent throughout the second and third trimesters. ATMs were phagocytic in the neonate and expressed interleukin-6, along with other pro-inflammatory gene products. These findings show that ATMs colonize the adipose tissue early in gestation, raising the possibility that intrauterine ATM–adipocyte communication may exist, eventually allowing ATMs to affect prenatal adipose tissue development. [ABSTRACT FROM AUTHOR]

Stimulation of thermogenesis by inducing uncoupling protein 1 (UCP1) expression in adipocytes is thought to promote weight loss by increasing energy expenditure, and it is postulated that the human newborn has thermogenic subcutaneous fat depots. However, it remains unclear whether a relevant number of UCP1-expressing (UCP1+) adipocytes exist in the early postnatal life. Here we studied the distribution of UCP1 and the expression of thermogenic genes in the subcutaneous adipose tissues of the human fetus, infant and child. We show that the deep layer of human fetal and neonatal subcutaneous fat, particularly the abdominal wall, is rich in UCP1+ adipocytes. These adipocytes develop in the late third trimester and persist throughout childhood, expressing a panel of genes linked to mitochondrial biogenesis and thermogenesis. During the early childhood adiposity rebound—a critical phase that determines obesity risk later in life—the absence of adipose tissue UCP1 expression in children with normal body mass index (BMI) correlates with an obesity-associated gene expression signature. Finally, UCP1 expression is negatively correlated with BMI z-score and adipocyte size in infants and children. Overall, our results show that the absence of UCP1 expression in adipose tissue is an early indicator of adipose tissue expansion in children. [ABSTRACT FROM AUTHOR]

Innate immune signaling in adipocytes affects systemic metabolism. Cytosolic nucleic acid sensing has been recently shown to stimulate thermogenic adipocyte differentiation and protect from obesity; however, DNA efflux from adipocyte mitochondria is a potential proinflammatory signal that causes adipose tissue dysfunction and insulin resistance. Cytosolic DNA activates the stimulator of interferon response genes (STING), a key signal transducer which triggers type I interferon (IFN-I) expression; hence, STING activation is expected to induce IFN-I response and adipocyte dysfunction. However, we show herein that mouse adipocytes had a diminished IFN-I response to STING stimulation by 2′3′-cyclic-GMP-AMP (cGAMP). We also show that cGAMP triggered autophagy in murine and human adipocytes. In turn, STING inhibition reduced autophagosome number, compromised the mitochondrial network and caused inflammation and fat accumulation in adipocytes. STING hence stimulates a process that removes damaged mitochondria, thereby protecting adipocytes from an excessive IFN-I response to mitochondrial DNA efflux. In summary, STING appears to limit inflammation in adipocytes by promoting mitophagy under non-obesogenic conditions. [ABSTRACT FROM AUTHOR]

Background: Leukemic B-cell precursor (BCP) lymphoblasts were identified as a novel expression site for coagulation factor XIII subunit A (FXIII-A). Flow cytometry (FC) revealed three distinct expression patterns, i.e., FXIII-A negative, FXIII-A dim, and FXIII-A bright subgroups. The FXIII-A negative subgroup was significantly associated with the "B-other" genetic category and had an unfavorable disease outcome. Methods: RNA was extracted from bone marrow lymphoblasts of 42 pediatric patients with BCP-acute lymphoblastic leukemia (ALL). FXIII-A expression was determined by multiparameter FC. Genetic diagnosis was based on conventional cytogenetic method and fluorescence in situ hybridization. Affymetrix GeneChip Human Primeview array was used to analyze global expression pattern of 28,869 well-annotated genes. Microarray data were analyzed by Genespring GX14.9.1 software. Gene Ontology analysis was performed using Cytoscape 3.4.0 software with ClueGO application. Selected differentially expressed genes were validated by RT-Q-PCR. Results: We demonstrated, for the first time, the general expression of F13A1 gene in pediatric BCP-ALL samples. The intensity of F13A1 expression corresponded to the FXIII-A protein expression subgroups which defined three characteristic and distinct gene expression signatures detected by Affymetrix oligonucleotide microarrays. Relative gene expression intensity of ANGPTL2, EHMT1 FOXO1, HAP1, NUCKS1, NUP43, PIK3CG, RAPGEF5, SEMA6A, SPIN1, TRH , and WASF2 followed the pattern of change in the intensity of the expression of the F13A1 gene. Common enhancer elements of these genes revealed by in silico analysis suggest that common transcription factors may regulate the expression of these genes in a similar fashion. PLAC8 was downregulated in the FXIII-A bright subgroup. Gene expression signature of the FXIII-A negative subgroup showed an overlap with the signature of "B-other" samples. DFFA, GIGYF1, GIGYF2 , and INTS3 were upregulated and CD3G was downregulated in the "B-other" subgroup. Validated genes proved biologically and clinically relevant. We described differential expression of genes not shown previously to be associated with pediatric BCP-ALL. Conclusions: Gene expression signature according to FXIII-A protein expression status defined three novel subgroups of pediatric BCP-ALL. Multiparameter FC appears to be an easy-to-use and affordable method to help in selecting FXIII-A negative patients who require a more elaborate and expensive molecular genetic investigation to design precision treatment. [ABSTRACT FROM AUTHOR]

Objectives Autophagy is an evolutionarily conserved process playing an important role in tumor cell's resistance to chemotherapy. Response to glucocorticoid ( GC) treatment is out of the most important prognostic factors in childhood acute lymphoblastic leukemia ( ALL); however, only few data are available connecting GC response and role of autophagy. Our aim was to investigate whether altered expression of autophagy-related genes contributes to GC-resistant phenotype in GC-sensitive and GC-resistant precursor B-cell-type ( PBC) ALL cells. Methods Gene expression data were obtained from public database for 26 children diagnosed with PBC ALL either sensitive or resistant to in vitro prednisolone treatment. Results We have identified 36 autophagy-associated genes which were differently expressed, based on at least a twofold difference, GC-sensitive group as compared to GC-resistant one. Of the 36 genes, 10 were downregulated and 26 upregulated in the GC-resistant group. The average fold change values for the decreased and increased transcripts were −4.57 and 2.67, respectively. Conclusions Our data imply that GC sensitivity might depend on the expression of several genes involved in regulation and execution of autophagy in a way that key autophagy inducers are downregulated while inhibitors of autophagy are upregulated in GC-resistant cells. [ABSTRACT FROM AUTHOR]

Background: Based on previous retrospective results, we investigated the association of coagulation FXIII subunit A (FXIII-A) expression pattern on survival and correlations with known prognostic factors of B-cell progenitor (BCP) childhood acute lymphoblastic leukemia (ALL) as a pilot study of the prospective multi-center BFM ALL-IC 2009 clinical trial. Methods: The study included four national centers (n = 408). Immunophenotyping by flow cytometry and cytogenetic analysis were performed by standard methods. Copy number alteration was studied in a subset of patients (n = 59). Survival rates were estimated by Kaplan-Meier analysis. Correlations between FXIII-A expression patterns and risk factors were investigated with Cox and logistic regression models. Results: Three different patterns of FXIII-A expression were observed: negative (<20%), dim (20–79%), and bright (≥80%). The FXIII-A dim expression group had significantly higher 5-year event-free survival (EFS) (93%) than the FXIII-A negative (70%) and FXIII-A bright (61%) groups. Distribution of intermediate genetic risk categories and the "B-other" genetic subgroup differed significantly between the FXIII-A positive and negative groups. Multivariate logistic regression confirmed independent association between the FXIII-A negative expression characteristics and the prevalence of intermediate genetic risk group. Conclusions: FXIII-A negativity is associated with dismal survival in children with BCP-ALL and is an indicator for the presence of unfavorable genetic alterations. [ABSTRACT FROM AUTHOR]