Koyama N, Harada K, Yamamoto A, Morisaki N, Saito Y, Yoshida S
Second Department of Internal Medicine, School of Medicine, Chiba University, Japan.
J Biol Chem. 1993 Jun 25;268(18):13301-8.
Migration of medial smooth muscle cells (SMC) into the intima is a key step in intimal thickening of atherosclerotic tissues. We previously reported that cultured SMC secrete a potent migration factor for SMC, named SMC-derived migration factor (SDMF). We purified this factor to homogeneity from 20 liters of serum-free conditioned medium of cultured rat aortic SMC by sequential heparin-Sepharose column, red-Sepharose column, TSK-heparin high performance liquid chromatography (HPLC) column, and Superose 6 HPLC column chromatographies. SDMF was found to be a 58-kDa polypeptide by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Reduction by mercaptoethanol caused only a slight decrease in its molecular mass to 53 kDa. Preparative isoelectric focusing revealed that SDMF is a basic protein with a pI of approximately 10. Purified SDMF enhanced the migration of rat SMC dose dependently, its maximal activity being 4 times that of platelet-derived growth factor-BB. In contrast, SDMF did not enhance the migration of endothelial cells from either human umbilical cord vein or rabbit retinal tissue. SDMF had no effect on the proliferation of SMC. These findings suggest that SDMF enhances SMC migration in vascular walls and that the autocrine system of SMC migration contributes to the formation of intimal thickening in atheroma formation.
内侧平滑肌细胞（SMC）向内膜迁移是动脉粥样硬化组织内膜增厚的关键步骤。我们之前报道过，培养的SMC分泌一种对SMC有强大作用的迁移因子，命名为SMC衍生迁移因子（SDMF）。我们通过依次使用肝素 - 琼脂糖柱、红色琼脂糖柱、TSK - 肝素高效液相色谱（HPLC）柱和Superose 6 HPLC柱色谱法，从20升培养的大鼠主动脉SMC无血清条件培养基中纯化该因子至同质。通过十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳发现SDMF是一种58 kDa的多肽。用巯基乙醇还原仅使其分子量略有下降至53 kDa。制备性等电聚焦显示SDMF是一种碱性蛋白，pI约为10。纯化的SDMF剂量依赖性地增强大鼠SMC的迁移，其最大活性是血小板衍生生长因子 - BB的4倍。相反，SDMF不增强来自人脐静脉或兔视网膜组织的内皮细胞的迁移。SDMF对SMC的增殖没有影响。这些发现表明SDMF增强血管壁中SMC的迁移，并且SMC迁移的自分泌系统有助于动脉粥样硬化形成过程中内膜增厚的形成。
