Chen Ji-De, Xu Fen-Fen, Zhu Heng, Li Xi-Mei, Tang Bo, Liu Yuan-Lin, Zhang Yi
Department of Clinical Laboratorial Examination, Chinese PLA Hospital 169, Hengyang 421002, Hunan Province, China; Department of Cell Biology, Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, China.
Department of Pediatrics, General Hospital of Tinajin Medical University, Tianjing 300052, China; Department of Cell Biology, Institute of Basic Medical Sciences, Academy of Military Medical Sciences, Beijing 100850, China.
Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2014 Feb;22(1):160-5. doi: 10.7534/j.issn.1009-2137.2014.01.031.
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 adipocyte 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 smaller 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 pathway.
本研究旨在探讨细胞间黏附分子-1（ICAM-1）对间充质干细胞（MSC）向脂肪细胞分化的调控作用的分子机制。用含有质粒MIGR1-ICAM-1和MIGR1-ICAM-1/MSC（ICAM-1高表达）的上清液处理小鼠MSC细胞系C3H10T 1/2，通过蛋白质免疫印迹法检测该通路的激活情况。将ICAM-1修饰的MSC及其对照细胞MIGR1/MSC在有或无细胞外调节蛋白激酶（ERK）、p38丝裂原活化蛋白激酶（P38）和c-Jun氨基末端激酶（JNK）通路抑制剂的脂肪细胞培养基中培养。采用油红O染色检测脂质蓄积情况，并通过实时定量聚合酶链反应检测MSC向脂肪细胞分化过程中C/EBPα和过氧化物酶体增殖物激活受体γ（PPARγ）的表达。结果显示，ICAM-1的过表达稳定激活了MSC中的ERK、P38和JNK通路。化学抑制剂抑制ERK通路的激活上调了MIGR1-ICAM-1/MSC中C/EBPα和PPARγ的mRNA表达水平，而抑制P38通路则导致转录因子的mRNA表达降低。与mRNA表达一致，抑制P38通路时脂滴变小且脂肪细胞数量增加，而添加ERK通路抑制剂时MIGR1-ICAM-1/MSC中脂滴变大且脂肪细胞数量增加。结论是，ICAM-1可能通过激活ERK通路抑制MSC向脂肪细胞分化，而通过P38通路维持MSC的脂肪生成。
