钙信号调节小鼠前体脂肪细胞分化和脂质蓄积的机制

The mechanism of calcium signal regulate preadipocyte differentiation and lipid accumulation in mice

摘要:

本试验用醋酸钙、p38丝裂原激活蛋白激酶(p38 MAPK)抑制剂SB203580及钙通道阻滞剂和激动剂刺激小鼠前体脂肪细胞。通过实时定量PCR技术检测前体脂肪细胞分化标志基因和钙信号相关受体基因表达水平, 用油红O染色提取法和Fura-2/AM荧光法测定胞内脂质蓄积情况及胞浆游离Ca2+浓度([Ca2+]i)变化, 以探讨钙信号调节前体脂肪细胞分化的潜在机制。结果表明：钙通道阻滞剂和激动剂显著改变了脂蛋白脂酶(LPL), 过氧化物增殖激活受体 γ(PPARγ)、脂肪酸合成酶(FAS)的表达水平，且影响细胞内的脂质蓄积。与降低外钙摄入相比，降低内钙释放能促进前体脂肪细胞分化(P<0.01)，而提高外钙摄入与提高内钙释放相比，提高外钙摄入显著抑制前体脂肪细胞分化(P<0.01)。 SB203580可降低胞浆[Ca2+]i浓度，促进前体细胞分化和脂质蓄积(P<0.01)。但钙信号并未影响维生素D受体(VDR)和细胞外钙敏感受体(CaSR)的表达水平。提示钙信号可能通过p38 MAPK通路影响前体脂肪细胞分化和脂质蓄积。

Abstract:

We stimulated preadipocyte of mice with calcium acetate, p38 mitogen-activated protein kinase (p38 MAPK) inhibitor SB203580, the paralysors and excitomotors of calcium channel. Then we detected expression level of preadipocyte differentiation’s marker genes and calcium signal related acceptor genes by real-time PCR, and determined intracellular free Ca2+ concentration ([Ca2+]i]) with Fura-2/AM, intracellular lipid accumulation by oil red O staining. Our aim was to investigate the potential mechanism between calcium signal and preadipocyte differentiation. The results indicated that the paralysors and excitomotors of calcium channel changed the expression level of lipoprotein lipase (LPL), peroxisome proliferators-activated receptor gamma (PPARγ), fatty acid synthetase (FAS), and the lipid accumulation, markedly. Compared with exocellular Ca2+’s decrease, inhibited intracellular Ca2+’s liberation can promoted preadipocyte differentiation (P<0.01), and compared with intracellular Ca2+’s increase, promoted exocellular Ca2+’s ingest inhibited preadipocyte differentiation (P<0.01). SB203580 degraded [Ca2+]i, promoted differentiation marker genes’ expression and lipid accumulation in preadipocyte (P<0.01). But calcium signal didn’t have effects to vitamin D receptor (VDR) and extracellular Ca2+-sensing receptor (CaSR)’s expression. It indicated that calcium signal may effect preadipocyte different and lipid accumulation by p38 MAPK pathway.