Zhang Fan, Tsai Shirling, Kato Kaori, Yamanouchi Dai, Wang Chunjie, Rafii Shahin, Liu Bo, Kent K Craig
Department of Surgery, University of Wisconsin School of Medicine, Madison, Wisconsin 53705, USA.
J Biol Chem. 2009 Jun 26;284(26):17564-74. doi: 10.1074/jbc.M109.013987. Epub 2009 Apr 30.
Bone marrow-derived progenitor cells have recently been shown to be involved in the development of intimal hyperplasia after vascular injury. Transforming growth factor-beta (TGF-beta) has profound stimulatory effects on intimal hyperplasia, but it is unknown whether these effects involve progenitor cell recruitment. In this study we found that although TGF-beta had no direct effect on progenitor cell recruitment, conditioned media derived from vascular smooth muscle cells (VSMC) stimulated with TGF-beta induced migration of both total bone marrow (BM) cells and BM-mesenchymal stem cells (MSC) and also induced MSC differentiation into smooth muscle like cells. Furthermore, overexpression of the signaling molecule Smad3 in VSMC via adenovirus-mediated gene transfer (AdSmad3) enhanced the TGF-beta's chemotactic effect. Microarray analysis of VSMC stimulated by TGF-beta/AdSmad3 revealed monocyte chemoattractant protein-1 (MCP-1) as a likely factor responsible for progenitor cell recruitment. We then demonstrated that TGF-beta through Smad3 phosphorylation induced a robust expression of MCP-1 in VSMC. Recombinant MCP-1 mimicked the stimulatory effect of conditioned media on BM and MSC migration. In the rat carotid injury model, Smad3 overexpression significantly increased MCP-1 expression after vascular injury, consistent with our in vitro results. Interestingly, TGF-beta/Smad3-induced MCP-1 was completely blocked by both Ro-32-0432 and rotterlin, suggesting protein kinase C-delta (PKCdelta) may play a role in TGF-beta/Smad3-induced MCP-1 expression. In summary, our data demonstrate that TGF-beta, through Smad3 and PKCdelta, stimulates VSMC production of MCP-1, which is a chemoattractant for bone marrow-derived cells, specifically MSC. Manipulation of this signaling system may provide a novel approach to inhibition of intimal hyperplasia.
最近研究表明，骨髓来源的祖细胞参与血管损伤后内膜增生的发展过程。转化生长因子-β（TGF-β）对内膜增生具有显著的刺激作用，但这些作用是否涉及祖细胞募集尚不清楚。在本研究中，我们发现尽管TGF-β对祖细胞募集没有直接影响，但用TGF-β刺激血管平滑肌细胞（VSMC）得到的条件培养基可诱导全骨髓（BM）细胞和BM间充质干细胞（MSC）迁移，还能诱导MSC分化为平滑肌样细胞。此外，通过腺病毒介导的基因转移（AdSmad3）在VSMC中过表达信号分子Smad3可增强TGF-β的趋化作用。对TGF-β/AdSmad3刺激的VSMC进行微阵列分析发现，单核细胞趋化蛋白-1（MCP-1）可能是负责祖细胞募集的因子。然后我们证明，TGF-β通过Smad3磷酸化诱导VSMC中MCP-1的强烈表达。重组MCP-1模拟了条件培养基对BM和MSC迁移的刺激作用。在大鼠颈动脉损伤模型中，Smad3过表达显著增加血管损伤后MCP-1的表达，与我们的体外实验结果一致。有趣的是，TGF-β/Smad3诱导的MCP-1被Ro-32-0432和rottlerin完全阻断，提示蛋白激酶C-δ（PKCδ）可能在TGF-β/Smad3诱导的MCP-1表达中起作用。总之，我们的数据表明，TGF-β通过Smad3和PKCδ刺激VSMC产生MCP-1，MCP-1是骨髓来源细胞（特别是MSC）的趋化因子。对该信号系统的调控可能为抑制内膜增生提供一种新方法。
