Search of new regulating factors and its regulatory mechanism for proliferation and differentiation in ruminant adipocytes.

本研究的主要结果如下：1.建立了绵羊成熟脂肪细胞与前体脂肪细胞共培养体系，实验数据表明成熟脂肪细胞对前体脂肪细胞的增殖和分化具有调节作用。2.绵羊脂肪细胞主动合成和分泌多种细胞色素家族成员，如瘦素和肿瘤坏死因子-α。它们是成熟脂肪细胞和前脂肪细胞增殖和分化的抑制因子，它们的合成和分泌受胰岛素和胰岛素样生长因子-I 3的调节。我们的研究表明，MAP和PI3-激酶的激活分别参与了绵羊前脂肪细胞的增殖和分化过程，而PPAR-γ的激活可能是激活PPAR4所必需的。4.接下来，我们寻找了与脂肪形成相关的新基因。(1)脂肪细胞特异性基因Adipogenin在脂肪细胞分化过程中表达上调，提示脂肪生成素可能参与脂肪的形成，作为脂肪组织发育的调节因子之一。(2)以短链脂肪酸为配体的G蛋白偶联受体家族GPCR43，在前体脂肪细胞分化过程中，其mRNA表达上调。丙酸通过GPCR43抗脂作用促进前脂肪细胞分化

Summary of this research results is listed below.1.We have established a co-culture system with ovine mature adipocytes and preadipocytes and the data from their experiments indicate that mature adipocytes regulate proliferation and differentiation of preadipocytes.2.Ovine adipocytes actively synthesis and secrete many members of the cytoldne family, such as leputin and TNF-α. They act as inhibitory factor in proliferation and differentiation of mature adipocytes and preadipocytes, and the synthesis and secretion of them are regulated by insulin and IGF-I.3.Our studies demonstrated that the activation of MAP kinase and PI3-kinase contributes to the proliferation and differentiation process of ovine preadipocytes, respectively, and the activation of PI3-kinase may be necessary in the activation of a nuclear transcription factor, PPAr-γ.4.Next, we have searched out new genes related to adipogenesis.(1)Adipogenin, a new adipocyte-specific gene, have been identified Since the expression of adipogenin mRNA is up-regulated during adipocyte differentiation, it is indicated that adipogenin may be involved with adipogenesis, as one of the regulatory of the adipose tissue development.(2)GPCR43, G protein-coupled receptor family having short chain fatty acids as their ligand, mRNA is up-regulated during preadipocyte differentiation. The stimulatory effect of propionate in differentiation of preadipocytes due to anti-lipolytic action through GPCR43.