Fibroblast Growth Factor 21 Suppresses Adipogenesis in Pig Intramuscular Fat Cells
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
Authors: Wang, Yongliang; Liu, Xinyi; Hou, Liming; Wu, Wangjun; Zhao, Shuhong; Xiong, Yuanzhu
Abstract
Fibroblast growth factor 21 (FGF21) plays an important role in the treatment of disease associated with muscle insulin resistance which is characterized by various factors, such as intramuscular triglyceride (IMT) content. Studies have also shown that FGF21 inhibits triglyceride synthesis in vivo. However, the precise mechanism whereby FGF21 regulates triglyceride metabolism in intramuscular fat (IMF), which may influence the muscle insulin sensitivity, is not clearly understood. In order to understand the role of FGF21 in IMF deposition, we performed FGF21 overexpression in IMF cells by stable transfection. Our results showed that FGF21 inhibited the key adipogenesis gene mRNA expression of peroxisome proliferator-activated receptor gamma (PPARG), CCAAT/enhancer-binding protein (CEBP) family by reducing lysine-specific demethylase 1 (LSD1) expression which led to significant decline in lipid accumulation, and the result was confirmed byWestern blot. Moreover, triggered by FGF21, parts of the adipokines-fatty acid-binding protein 4 (FABP4), glucose transporter 4 (GLUT4), adiponectin (ADIPOQ), and perilipin (PLIN1)-were also down-regulated. Furthermore, FGF21 gene expression was suppressed by transcription factor CEBP beta (CEBPB) which contributed strongly to triglyceride synthesis. Taken together, our study is the first to experimentally demonstrate FGF21 emerging as an efficient blockade of adipogenesis in IMF, thus also providing a new understanding of the mechanism whereby FGF21 improves insulin sensitivity.
Pulmonary endothelial cell DNA methylation signature in pulmonary arterial hypertension
ONCOTARGET
Authors: Hautefort, Aurelie; Chesne, Julie; Preussner, Jens; Pullamsetti, Soni S.; Tost, Jorg; Looso, Mario; Antigny, Fabrice; Girerd, Barbara; Riou, Marianne; Eddahibi, Saadia; Deleuze, Jean-Francois; Seeger, Werner; Fadel, Elie; Simonneau, Gerald; Montani, David; Humbert, Marc; Perros, Frederic
Abstract
Pulmonary arterial hypertension (PAH) is a severe and incurable pulmonary vascular disease. One of the primary origins of PAH is pulmonary endothelial dysfunction leading to vasoconstriction, aberrant angiogenesis and smooth muscle cell proliferation, endothelial-to-mesenchymal transition, thrombosis and inflammation. Our objective was to study the epigenetic variations in pulmonary endothelial cells (PEC) through a specific pattern of DNA methylation. DNA was extracted from cultured PEC from idiopathic PAH (n = 11), heritable PAH (n = 10) and controls (n = 18). DNA methylation was assessed using the Illumina HumanMethylation450 Assay. After normalization, samples and probes were clustered according to their methylation profile. Differential clusters were functionally analyzed using bioinformatics tools. Unsupervised hierarchical clustering allowed the identification of two clusters of probes that discriminates controls and PAH patients. Among 147 differential methylated promoters, 46 promoters coding for proteins or miRNAs were related to lipid metabolism. Top 10 up and down-regulated genes were involved in lipid transport including ABCA1, ABCB4, ADIPOQ, miR-26A, BCL2L11. NextBio meta-analysis suggested a contribution of ABCA1 in PAH. We confirmed ABCA1 mRNA and protein downregulation specifically in PAH PEC by qPCR and immunohistochemistry and made the proof-of-concept in an experimental model of the disease that its targeting may offer novel therapeutic options. In conclusion, DNA methylation analysis identifies a set of genes mainly involved in lipid transport pathway which could be relevant to PAH pathophysiology.