GDF5 Promotes White Adipose Tissue Thermogenesis via p38 MAPK Signaling Pathway.

Growth differentiation factor 5 (GDF5) was reported to regulate brown adipogenesis; however, its effects on insulin sensitivity, full metabolic syndrome spectrum, and the thermogenesis in subcutaneous white adipose tissue (sWAT) have not been elucidated yet. We thus generated fatty acid-binding protein 4 (Fabp4)-GDF5 transgenic (TG) mice and showed that GDF5 TG mice developed a relative lean phenotype on a high-fat diet (HFD) and showed increased insulin sensitivity. Over expression of GDF5 in adipose tissues greatly promoted the thermogenic process in sWAT after cold or β3-agonist treatment. In TG mice, sWAT showed an important thermogenic effect as the thermogenic gene expression was markedly increased, which was consistent with the typical features of beige adipocytes. Moreover, knockdown of the protein GDF5 impaired browning program in sWAT after thermogenic stimuli. Enhanced mitogen-activated protein kinase (MAPK)/activating transcription factor 2 (ATF2) signaling was also identified in sWAT of HFD-fed GDF5 mice, and thermogenesis in mature adipocytes induced by GDF5 protein could be partly blocked by a p38 MAPK inhibitor. Taken together, our data suggest that GDF5 could improve insulin sensitivity and prevent metabolic syndrome, the adaptive thermogenesis in sWAT could mediate the obesity resistance effects of GDF5 in mice and partially resulted in the activation of the p38 MAPK signaling pathway.