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Effects of platelet-derived profilin on vascular smooth muscle cells and endothelial cells.

血小板衍生的profin对血管平滑肌细胞和内皮细胞的影响。

基本信息

批准号：
11670727
负责人：
NAKASHIMA Yasuhide
金额：
$ 2.18万
依托单位：
University of Occupational and Environmental Health
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

项目摘要

Profilin is known to bind to actin monomers to regulate actin polymerization, and to phosphatidylinositol 4,5-bisphosphate to inhibit hydrolysis by unphosphorylated phospholipase C-γ1. We recently reported that profilin is overexpressed in glomerular mesangial cells of anti-Thy-1.1 glomerulonephritis rats and is accumulated in the extracellular space around mesangial cells. In the present study, we examined the biological activities of extracellular profilin. Scatchard analysis indicated the existence of a single class of cell surface binding site with similar K_ds for purified splenic and recombinant profilin in cultured rat mesangial cells. Profilin increased [^3H]thymidine incorporation in a dose-dependent manner and had additive effects on PDGF-induced [^3H]thymidine incorporation. Profilin increased AP-1 DNA binding activity in a concentration- (ED_<50> = 30 nM) and time-dependent manner followed the transient gene expression of c-jun measured by gel shift assay and competitive reverse transcribed-PCR.Pretreatment of profilin with anti-profilin inhibitory antibody suppressed profilin-induced AP-1 activation and [^3H]thymidine incorporation. Furthermore, profilin induced a rapid and transient activation of protein kinase C, and staurosporine and H-7 diminished profilin-induced activation of AP-1, suggesting protein kinase C-dependent activation of AP-1. These findings indicate that profilin in the extracellular space can bind to cell surface receptors of mesangial cells and act as an inducer of signal transduction. These results suggest that extracellular profilin may be involved in the progression of glomerular diseases by affecting cell growth.

Profilin与肌动蛋白单体结合调节肌动蛋白聚合，与磷脂酰肌醇4,5-二磷酸结合抑制未磷酸化磷脂酶C-γ - 1的水解。我们最近报道了profilin在抗thy -1.1型肾小球肾炎大鼠肾小球系膜细胞中过表达，并在系膜细胞周围的细胞外空间中积累。在本研究中，我们检测了细胞外profilin的生物活性。Scatchard分析表明，在培养的大鼠系膜细胞中存在一类具有相似K_ds的纯化脾蛋白和重组profilin的细胞表面结合位点。Profilin以剂量依赖的方式增加[^3H]胸腺嘧啶掺入，并对pdgf诱导的[^3H]胸腺嘧啶掺入具有累加效应。凝胶移位法和竞争性反转录pcr检测c-jun基因瞬时表达后，Profilin以浓度（ED_<50> = 30 nM）和时间依赖性方式增加AP-1 DNA结合活性。用抗profilin抑制抗体预处理profilin可抑制profilin诱导的AP-1活化和[^3H]胸腺嘧啶掺入。此外，profilin诱导了蛋白激酶C的快速和短暂激活，staurosporine和H-7降低了profilin诱导的AP-1的激活，表明AP-1的激活依赖于蛋白激酶C。这些发现表明，细胞外空间的profilin可以与系膜细胞的细胞表面受体结合，并作为信号转导的诱导剂。这些结果提示细胞外谱蛋白可能通过影响细胞生长参与肾小球疾病的进展。