P311 Modulates Adipocyte Development

Abstract

Adipogenesis is a complex process of adipocytes formed from progenitor cells that involves changes in gene expression, cell morphology and hormone sensitivity. The differentiation of adipocytes is regulated by a well‐orchestrated network of transcriptional factors and associated cell signaling proteins responsible for adipocyte development and maturation. An in‐depth understanding of adipogenesis is essential to fight against metabolic disorders including obesity. Our lab investigates the P311 protein that plays a key role in adipocyte development. P311 has been shown to play an essential role in blood pressure regulation and vascular contractility (Badri et al., J Clin Inv 2013). In this study, we evaluate the adipogenic function of P311 using NIH3T3‐L1 cell culture model and genetically modified animal models. We show that P311 expression, initiated with the induction of adipogenesis in 3T3‐L1 cells, increased during the adipogenesis process. Additionally, siRNA mediated P311 knockdown inhibited adipogenic differentiation in 3T3‐L1 cells. The increase in P311 expression during adipogenesis correlated with the increase in the expression of key adipogenic transcriptional factors PPARγ2 and C/EBPα. Further, we observed nuclear localization of P311 in immunofluorescence studies indicating potential transcriptional regulatory/co‐regulatory function/s of P311. To verify the transcriptional regulatory/co‐regulatory functions of P311, we conducted chromatin immunoprecipitation (ChIP) assays using adipogenesis induced 3T3‐L1 cells transfected with pCMV‐P311 or an empty vector, pCMV. P311 overexpressing adipocytes demonstrated the recruitment of P311 to the PPARγ2 promoter regions (~800 fold) compared to empty vector transfected adipocytes. However, P311 immunocomplexes failed to amplify C/EBPα promoter. Further, to verify the involvement of P311 in adipose tissue development, we conducted animal studies and did not find any differences in the white fat weights (gonadal and subcutaneous fat) between wild type mice (WT) and P311 knockout mice (KO) (18–21 weeks). However, we observed an increase in the numbers of LipidTox stained adipocytes as detected in fluorescenceactivated cell sorting (FACS) analysis in white fat of WT mice than P311 KO mice. Our current studies demonstrate the critical role of P311 in adipocyte development through the transcriptional regulation of PPARγ2.Support or Funding InformationThis study is supported by grant funds from NIMHD/NIH (U54MD008621 to Hampton University and S21MD000101).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.