Pathogenesis and molecular mechanisms of arteral restenosis

点击翻译按钮获取中文摘要

We previously demonstrated that rabbit and rat smooth muscles contain at least three types of MHCs ; SM1(204kDa), SM2(200kDa)and SMemb(200kDa). SM1 and SM2 are two smooth muscle specific MHC isoforms arising from a singlegene, and SMemb is a third type of MHC isoform abundantly expressed in embryonic aortas. The expression of three MHC isoforms is developmentallyregulated.The presence of developmentallyregulated MHC isoforms in vascular smooth muscles provides importantmoleculartools to investigate the molecularmechanism underlying vascular diseases. We first demonstrated that the developmentalregulation of myosin heavy chain expression occurs in proliferating smooth muscle cells after percutaneous angioplasty(PTCA) ; SMemb was reexpressed and SM2 was downregulated. We therefore characterized the promoter region of the SM1/2 and SMemb genes. In this study, we identified an important cis element for the SMemb gene and a transcription factor, BTEB-2, which coordinately regulate the SMemb gene.We furthermore characterized SM1/2 gene which is most specifically expressed in smooth muscles. SM1/2 gene harbors two CCTCCC elements-80 bp upstream of the transcription initiation site. These elements play a basic role for SM1/2 gene transcription but does not necessarily regulate smooth muscle-specific expression.