The Expression And Interaction Of PGC-1β And SREBP-1c During Porcine Adipocyt Differentiation

Adipose tissue as an important organ of energy regulation and endocrine, and the improvement of livestock fleshy and the human metabolic diseases such as obesity and type II diabetes and cardiovascular disease are all involved in fat deposit. So understanding adipocyte differentiation is of great significance for gaining insight into the livestock genetic breeding and pathogenesis of human metabolic diseases.Adipocyte differentiation is one complex network of regulatory processes, which involved in many key genes and signal pathways. PGC-1βas an activator of adipocyte differentiation markers PPARγ, it could play roles through coactivating a number of transcription factors. We have found that PGC-1βwas closely related to adipocyte differentiation, and the fat content of PGC-1βknockout mice was significantly reduced, but its mechanism in adipocyte differentiation is unclear currently. SREBP-1c as another important determinant factor of adipogenesis, played an important role in adipogenic of adipose and liver tissue. Moreover, we found that PGC-1βcould regulate adipogenesis by coactivating SREBP-1c in liver, but it is still unknown that whether there are similar adipogenic mechanisms in adipocytes.In order to discuss the problems mentioned above, 1-3 days piglets were used as our experimental animals. We detected the expression pattern of PGC-1βand SREBP-1c during porcine adipocyte differentiation by Real-time PCR, Western Blot and immunofluorescence method.Then, porcine primary adipocytes were infected with recombinant lentivirus interfering vector target on PGC-1β; Oil red O staining were used to determine the changes of triglyceride accumulation in cellular; the mRNA expression changes of PGC-1β, adipocyte differentiation markers PPARγ, SREBP-1c, its downstream target genes FAS and ACC were analyzed with Real-time PCR; The changes of PGC-1β, SREBP-1c, and adipocyte differentiation transcriptional factors C/EBPαproteins expression were analyzed with Western blot; Co-IP was used to investigate the interaction between PGC-1βand SREBP-1c proteins. In conclusion, we known the function of PGC-1βin regulating porcine adipocytes differentiation, and investigated the mechanism on modulating and interacting with SREBP-1c. The main results are as follows:1. PGC-1βand SREBP-1c are highly expressed in differentiated porcine adipocytes, and their expression gradually increased during adipocytes differentiation, accompanied with key genes PPARγand C/EBPαexpression. Besides, we observed that these two proteins located both in nucleus and cytoplasm in differentiated adipocytes, but main in cytoplasm.2. PGC-1βinterference significantly decreased the mRNA and protein expression of SREBP-1c, and inhibited adipocyte differentiation marker gene PPARγand C/EBPαexpression, the accumulation of triglyceride was also obviously reduced, so the differentiation of porcine adipocytes were inhibited.3. PGC-1βand SREBP-1c were interacted in protein levels in differentiated porcine adipocytes, it may be related to the mechanism of PGC-1βon regulating adipocyte differentiation.Intended to investigate the regulation and interaction of SREBP-1c on PGC-1βduring porcine preadipocytes differentiation, we preliminarily proved that the expression of PGC-1βand SREBP-1c were closely related to porcine adipocytes differentiation, interference of PGC-1βinhibited SREBP-1c expression and adipocyte differentiation. Furthermore, we identifinted the interaction between PGC-1βand SREBP-1c proteins in differentiated porcine adipocytes. It will provide a novel way to elucidate the function and mechanism of PGC-1βon modulating adipocyte differentiation.