Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, Peoples Republic of China.
Cell Biol Int. 2010 Dec;34(12):1155-61. doi: 10.1042/CBI20090304.
Thrombin acts as a potent mitogenic factor for ECs (endothelial cells) by the release of several growth factors, including PDGF-B (platelet-derived growth factor-B). CBP (CREB-binding protein), which functions as a transcriptional coactivator, links the changes in the extracellular stimuli with alterations in gene expression. Therefore, we hypothesized that CBP could mediate thrombin-induced proliferation of ECs via PDGF-B-dependent way. Short hairpin RNA was used to down-regulate the expression of CBP in ECs. CBP and PDGF-B levels were analysed by real-time RT-PCR and Western blot. To evaluate ECs proliferation, cell cycle and DNA synthesis were analysed by flow cytometry and BrdU (bromodeoxyuridine) incorporation assay, respectively. PDGF-B was involved in the mitogenic effect of thrombin on ECs. Down-regulation of CBP attenuated ECs proliferation and inhibited cell cycle progression induced by thrombin. Silencing CBP expression also suppressed thrombin-induced PDGF-B expression in ECs. Mitogenic activity of thrombin was impaired by silencing CBP expression in ECs. This inhibitory effect was, in part, related to the inability to up-regulate PDGF-B expression in ECs. CBP could be regarded as a potential therapeutic target for vascular injury.
凝血酶通过释放多种生长因子（包括血小板衍生生长因子-B [PDGF-B]），作为一种有效的有丝分裂原因子作用于 ECs（内皮细胞）。CBP（CREB 结合蛋白）作为转录共激活因子，将细胞外刺激的变化与基因表达的改变联系起来。因此，我们假设 CBP 可以通过 PDGF-B 依赖性途径介导凝血酶诱导的 ECs 增殖。使用短发夹 RNA 下调 ECs 中 CBP 的表达。通过实时 RT-PCR 和 Western blot 分析 CBP 和 PDGF-B 水平。通过流式细胞术和 BrdU（溴脱氧尿苷）掺入测定分别评估 ECs 的增殖、细胞周期和 DNA 合成。PDGF-B 参与了凝血酶对 ECs 的有丝分裂作用。下调 CBP 可减弱凝血酶诱导的 ECs 增殖并抑制细胞周期进程。沉默 CBP 表达也抑制了凝血酶诱导的 ECs 中 PDGF-B 的表达。沉默 CBP 表达可损害凝血酶在 ECs 中的有丝分裂活性。这种抑制作用部分与 ECs 中无法上调 PDGF-B 表达有关。CBP 可被视为血管损伤的潜在治疗靶点。
