血小板源生生长因子刺激血管平滑肌细胞增殖及其分子机制

目的：探讨血小板源生生长因子（PDGF－BB）刺激血管平滑肌细胞（VSMC）增殖及其分子机制。方法：用Western Blot法测定p44/p42 CCDPK活性。^3H]脱氧胸腺嘧啶核苷酸掺入测定VSMC DNA合成。原位杂交检测c-myc mRNA的表达。结果：PDGFBB诱导的磷酸化CCDPK蛋白表达和^3H]脱氧胸腺嘧啶核苷酸掺入呈浓度依赖性,此作用可被PTK抑制剂Genistein,外钙络合剂依他酸和MEK抑制剂PD 98059抑制。PDGF－BB刺激可引起c-myc mRNA的明显表达,此作用可被PD 98059抑制。结论：PDGF－BB通过激活p44/p42 CCDPK,上调c-myc mRNA的表达从而促进VSMC增殖,其作用是由PTK和Ca^2 介导的。

Platelet-derived growth factor stimulated vascular smooth muscle cell proliferation and its molecular mechanism

AIM: To study the molecular mechanism of platelet-derived growth factor (PDGF)-BB-stimulated vascular smooth muscle cell (VSMC) proliferation. METHODS: DNA synthesis was measured by 3H]thymidine incorporation. Phosphorylation of the 42- and 44-kDa Ca(2+)-calmodulin dependent protein kinase (CCDPK) was measured by Western blotting method. The expression of c-myc specific mRNA was detected by in situ hybridization. RESULTS: PDGF-BB (2 micrograms.L-1) induced DNA synthesis and activated CCDPK in a concentration-dependent manner and a induced a marked c-myc mRNA expression. Egtazic acid (EGTA, 5 mmol.L-1), genistein (400 mumol.L-1) or PD 98059 (50 mumol.L-1) reduced PDGF-BB (2 micrograms.L-1)-induced CCDPK activities and inhibited VSMC 3H]thymidine incorporation (P < 0.05). PD 98059 (50 mumol.L-1) also inhibited PDGF-BB (2 micrograms.L-1)-induced c-myc mRNA expression. CONCLUSION: PDGF stimulated VSMC proliferation by activation of p44/p42 CCDPK, which is mediated by Ca2+ and protein tyrosine kinase (PTK), and up-regulation of c-myc mRNA expression.