间充质干细胞成脂分化过程中SREBP-1对SIRT1的调控

Regulation of SIRT1 by SREBP-1 in Adipogenic Differentiation of Mesenchymal Stem Cells

目的:研究骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMMSC)成脂分化过程中转录因子SREBP-1对SIRT1的调控作用。方法:通过油红O染色鉴定BM M SC成脂分化;RT-PCR检测AP2、LPL、SREBF-1和SIRT1的mRNA转录水平;Western-blot检测SREBP-1表达水平;染色质免疫沉淀技术验证SREBP-1与SIRT1启动子之间的结合情况。结果:成脂诱导培养液中的BMMSC 14 d后被诱导成为成熟的脂肪细胞;RT-PCR显示AP2、LPL和SREBF-1、SIRT1在BMMSC成脂分化过程中表达上调;SREBP-1的蛋白水平也明显高表达;SREBP-1抗体免疫沉淀的基因组DNA成功扩增出SIRT1基因条带。结论:在BMMSC成脂分化过程中,SREBP-1能与SIRT1启动子区域特异性结合,可能参与SIRT1表达的调控。

Objective:To study the regulation of SIRTl by transcription factor SREBP-1 in adipogeneic differentiation of bone marrow mesenchymal stem cells(BMMSC).Methods:Oil red 0 staining was used to identify the adipogenic differentiation of BMMSC;the mRNA transcription levels of AP2,LPL,SREBFA,SIRT1 gene were detected by RT-PCR;the expession level of SREBP-1 was determined by Western-blot.The chromatin immunoprecipitation(ChIP) assay was used to investigate the binding of SREBP-1 to SIRT1 promoter.Results:BMMSC exposed to adipogenesis inducing medium become mature adipocytes at day 14;the mRNA transcription levels of AP2,LPL,SREBF-1,SIRT1 genes were up-regulated in adipocyte differentiation of BMMSC;the protein level of SREBP-1 was higher obviously;SIRT1 gene sequences was succesfully amplified from the genomic DNA immunoprecipitated by SREBP-1 antibody.Conclusion:SREBP-1 can bind to the promoter region of the SIRT1 gene in adipogenesis of BMMSC,and may be involved in the transcriptional regulation of the SIRT1 gene.