Response gene to complement 32 is required for C5b-9 induced cell cycle activation in endothelial cells.
Response gene to complement 32 is required for C5b-9 induced cell cycle activation in endothelial cells.
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DOI：
10.1016/j.yexmp.2008.12.005
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发表时间：
2009-04
影响因子：
3.6
通讯作者：
Rus, Horea
中科院分区：
文献类型：
--
作者：
Fosbrink, Matthew;Cudrici, Cornelia;Tegla, Cosmin A.;Soloviova, Kateryna;Ito, Takahiro;Vlaicu, Sonia;Rus, Violeta;Niculescu, Florin;Rus, Horea
血管内皮细胞(EC)和平滑肌细胞(SMC)的增殖是血管生成和动脉粥样硬化的关键事件。我们先前已经证明，补体激活过程中的C5b-9组装诱导了人主动脉内皮细胞(AEC)和SMC的细胞周期。C5b-9可以诱导补体反应基因(RGC)-32的表达，该基因的过度表达导致细胞周期的激活。因此，本研究通过siRNA下调内源性RGC-32的表达来检测内源性RGC-32对C5b-9诱导的细胞周期激活的需求。我们发现了两个RGC-32siRNAs，它们能显著降低AEC中RGC-32mRNA的表达。细胞内RGC-32的沉默抑制了C5b-9和血清生长因子诱导的DNA合成，提示RGC-32活性是进入S时相所必需的。RGC-32siRNA的敲除也显著降低了C5b-9诱导的CDC2的激活和Akt的磷酸化。CDC2在稳定高表达RGC-32的HeLa细胞的G1/S转变中不起作用。RGC-32被发现与Akt物理结合，并在体外被Akt磷酸化。RGC-32蛋白在Ser 45和Ser 47位突变可阻止Akt介导的磷酸化。此外，还发现RGC-32对AEC释放生长因子有调节作用。所有这些数据表明，C5b-9诱导AEC细胞周期依赖于RGC-32，这部分是通过调节Akt和生长因子的释放来实现的。
Proliferation of vascular endothelial cells (EC) and smooth muscle cells (SMC) is a critical event in angiogenesis and atherosclerosis. We previously showed that the C5b-9 assembly during complement activation induces cell cycle in human aortic EC (AEC) and SMC. C5b-9 can induce the expression of Response Gene to Complement (RGC)-32 and over expression of this gene leads to cell cycle activation. Therefore, the present study was carried out to test the requirement of endogenous RGC-32 for the cell cycle activation induced by C5b-9 by knocking-down its expression using siRNA. We identified two RGC-32 siRNAs that can markedly reduce the expression of RGC-32 mRNA in AEC. RGC-32 silencing in these cells abolished DNA synthesis induced by C5b-9 and serum growth factors, indicating the requirement of RGC-32 activity for S-phase entry. RGC-32 siRNA knockdown also significantly reduced the C5b-9 induced CDC2 activation and Akt phosphorylation. CDC2 does not play a role in G1/S transition in HeLa cells stably overexpressing RGC-32. RGC-32 was found to physically associate with Akt and was phosphorylated by Akt in vitro. Mutation of RGC-32 protein at Ser 45 and Ser 47 prevented Akt mediated phosphorylation. In addition, RGC-32 was found to regulate the release of growth factors from AEC. All these data together suggest that cell cycle induction by C5b-9 in AEC is RGC-32 dependent and this is in part through regulation of Akt and growth factor release.
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影响因子：
8
作者：
Donninger, H;Bonome, T;Birrer, MJ
通讯作者：
Birrer, MJ
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Fosbrink, M;Cudrici, C;Rus, H
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