509-P: the Nuclear Receptor Nr5a1 Promotes Adipogenesis As a Novel Transcriptional Regulator of PPARgamma

Introduction & Objective: The nuclear receptor subfamily 5 group A member 1 (Nr5a1) recognized as a transcription factor in adrenal and gonadal organs is also found to regulate lipid metabolism in the islets. However, its involvement in the development of white adipose tissue (WAT) in which peroxisome proliferator activated receptor gamma (PPARgamma) plays a key role remains to be elucidated. Herein, we aim to study the roles and effects of Nr5a1 in adipogenesis. Methods: Human and mice subcutaneous and visceral adipose tissue were harvested and primary adipose-derived preadipocytes were isolated and cultured in vitro. The expression of Nr5a1 in WAT and preadipocytes was validated by qPCR, western blot and immunofluorescence. RNA-seq and qPCR were conducted to discern downstream target genes. Oil-red O staining detected the lipid accumulation and western blot tested the expression of key factors in adipogenesis. The transcriptional regulation of Nr5a1 on the target gene was tested by CUT&tag and qPCR and luciferase reporter assays. Results: Nr5a1 levels were elevated in WAT of ob/ob and db/db and diet-induced-obese mice compared to their lean controls. In primary preadipocytes of human and mice, Nr5a1 expressed at a low-level while was dramatically upregulated during adipogenesis both in mRNA and protein level. GO analysis showed that overexpression of Nr5a1 in preadipocytes upregulated adipogenesis marker genes and lipid biosynthetic process. And it was demonstrated that adipogenesis was suppressed by knockdown of Nr5a1 while overexpression of Nr5a1 promoted it. In the process of adipogenesis, Nr5a1 promoted the transcription of PPARgamma by binding to its promoter. Conclusion: Nr5a1 promotes adipogenesis in WAT by upregulating the transcription of PPARgamma. Our findings highlight the roles of Nr5a1 in the adipocyte differentiation and lipid metabolism in WAT, positioning it as a potential target for obesity treatment. Disclosure Y. Cheng: None. Y. Guo: None. Y. Li: Consultant; Sanofi, Novo Nordisk, AstraZeneca.