Effects of calcium signal on the transcription of GPR120 and adipogenesis in mouse adipose tissue | 钙信号对小鼠脂肪组织中GPR120基因转录及脂肪生成的影响

chinois. 探讨钙信号对小鼠脂肪组织中GPR120基因转录及脂肪生成的影响。用外源性葡萄糖酸钙和二氢吡啶钙离子通道的阻滞剂Nifedipine处理小鼠30 d，记录小鼠体质量的变化，测定小鼠皮下脂肪、附睾脂肪和肾周脂肪的沉积量，检测血清中甘油三酯（TG）、总胆固醇（TC）、高密度脂蛋白胆固醇（HDL-C）和低密度脂蛋白胆固醇（LDL-C）的浓度，同时利用Real-time PCR法分析GPR120基因及与脂肪生成密切相关的转录因子PPARγ、C/EBPα和脂解基因HSL、生脂基因FAS mRNA的表达情况，用SPSS软件分析小鼠附睾脂肪中GPR120与脂代谢相关基因表达的相关性。葡萄糖酸钙可延缓小鼠体质量的增加，减少体脂含量（P＜0.01），并使小鼠血清中的TG、TC和LDL-C浓度极显著降低（P＜0.01），HDL-C浓度显著升高（P＜0.05），可导致GPR120、PPARγ、C/EBPα和FAS的mRNA表达水平降低，且分别达到极显著（P＜0.01）或显著（P＜0.05）水平，并可使HSL mRNA表达水平极显著升高（P＜0.01）；Nifedipine处理能使小鼠体质量增加（P＜0.05），促进体脂沉积（P＜0.01），并使小鼠血清中的TG和TC浓度显著升高（分别为P＜0.05 和P＜0.01），GPR120、PPARγ、C/EBPα和FAS的mRNA表达水平极显著升高（P＜0.01），但却使HSLmRNA的表达水平极显著降低（P＜0.01）。相关性分析表明，GPR120 mRNA的表达水平与PPARγ、FAS和C/EBPα间呈显著正相关。钙信号在GPR120调节小鼠脂肪生成的过程中可能起到负调控作用。

anglais. The present study aimed at exploring the effects of calcium signal on the transcription of GPR120 and adipogenesis in mouse adipose tissue. Mice were treated with Calglucon and Ca2+ antagonists Nifedipine respectively for 30 days. The body weight, subcutaneous fat tissue, periepididymal fat pads and perirenal fat pads were weighed, total cholesterol (TC), triglycerides (TG), high density lipoprotein cholesterol (HDL-C), and LDL-C were measured, and the expression levels of GPR120, two major transcriptional factors PPARγ and C/EBPαas well as HSL and FAS mRNA were measured by Real-time PCR, the correlations of GPR120 with adipose metabolism related genes in mice periepididymal fat were analyzed by using SPSS analysis software. The results showed that dietary calglucon can attenuate the increase of body mass and decrease body fat gain (P＜0.01), the concentrations of TG, TC and LDL-C in blood serum-decreased significantly (P＜0.01), and the expression levels of GPR120, PPARγ,C/EBPαand FAS mRNA was down-regulated (P＜0.05 and P＜0.01 respectively), while the expression level of HSL mRNA increased significantly (P＜0.01). In Nifedipine-treatment group, body fat mass increased significantly (P＜0.01), the levels of TG and TC in serum increased (P＜0.05 and P＜0.01 respectively), the expression levels of GPR120, PPARγ, C/EBPαand FAS mRNA were up-regulated (P＜0.01) while HSL mRNA decreased (P＜0.01). In mice periepididymal fat, the expression of GPR120 mRNA was correlated with PPARγ, FAS and C/EBPα but not with HSL. Calcium signal may play a negative regulation role in the process of adipogenesis mediated by GPR120.