细胞间黏附分子1通过活化MAPK通路调节小鼠间充质干细胞向脂肪细胞分化

ICAM-1 Regulates Differentiation of MSC to Adipocytes via Activating MAPK Pathway

本研究旨在探讨细胞间黏附分子-1(intercellular cell adhesion molecule-1,ICAM-1)调节小鼠间充质干细胞(mesenchymal stem cell,MSC)向脂肪细胞分化的分子机制。分别将小鼠ICAM-1重组逆转录病毒MIGR1-ICAM-1和空载体逆转录病毒MIGR1感染小鼠间充质干细胞系C3H10T 1/2细胞,获得稳定高表达ICAM-1的C3H10T 1/2细胞(MIGR1-ICAM-1/MSC)和对照组细胞(MIGR1/MSC)。通过Western blot检测P38,ERK和JNK通路的活化情况,观察MIGR1-ICAM-1/MSC和MIGR1/MSC向脂肪细胞的诱导分化。实验组加入P38、ERK及JNK 3种信号通路抑制剂后进行培养并观察其成脂肪分化情况。以原位油红染色观察脂滴,应用real-time PCR检测成脂分化关键转录因子C/EBPα和PPARγmRNA的表达水平。结果显示,ICAM-1过表达可活化MSC的P38、ERK及JNK通路;原位油红染色及real-time PCR检测结果显示对ERK通路活化抑制可导致MIGR1-ICAM-1/MSC的C/EBPα和PPARγ的mRNA表达水平上调,脂滴变大,脂肪数量增加(P<0.01);阻断P38通路后MIGR1-ICAM-1/MSC的C/EBPα和PPARγmRNA表达水平下调,脂滴及脂肪细胞数量更小、更少(P<0.01)。结论:ICAM-1可能通过活化ERK信号通路抑制MSC的成脂分化,通过活化P38通路维持小鼠MSC成脂分化能力。

This study was aimed to explore the molecular mechanism of the regulatory effects of ICAM-1 on the differentiation of mesenchymal stem cells （MSC） to adipocytes.The murine MSC cell line C3H10T 1/2 was treated with the supernatants contained plasmid MIGR1-ICAM-1 and MIGR1-ICAM-1/MSC （high expression of ICAM-1）,the activation of the pathway was detected by Western blot.The ICAM-1 modified MSC and its control cells named MIGR1/MSC were cultured in adipocytic medium with or without the inhibitors of the ERK,P38,and JNK pathway.Oil-red-O staining was used to detect the lipid accumulation,and the expression of C/EBPα and PPARγ in differentiation of MSC to adipocyte were examined by real-time-PCR.The results showed that the overexpression of ICAM-1 stably activated the ERK,P38,and JNK pathway in MSC.Inhibiting of the activation of ERK pathways by chemical inhibitors up-regulated the mRNA expression level of C/EBPα and PPARγ in MIGR1-ICAM-1/MSC while inhibiting of P38 pathway resulted in lower mRNA expression of the transcription factors.Consistent with the mRNA expression,the lipid droplets were getting smalier and number of adipocytes increased when P38 pathway was inhibited,while bigger lipid droplet and increased quantity of adipocytes were identified in MIGR1-ICAM-1/MSC with the addition of ERK pathway inhibitor.It is concluded that ICAM-1 may suppress MSC differentiate into adipocyte via activating ERK pathway,while it can maintain the adipogenesis of MSC though P38 pahtway.