Platelet-derived growth factor modulates rat vascular smooth muscle cell responses on laminin-5 via mitogen-activated protein kinase-sensitive pathways.
Platelet-derived growth factor modulates rat vascular smooth muscle cell responses on laminin-5 via mitogen-activated protein kinase-sensitive pathways.
复制标题
DOI：
10.1186/1478-811x-3-2
复制
发表时间：
2005-01-31
期刊：
影响因子：
--
通讯作者：
Plopper GE
中科院分区：
文献类型：
--
作者：
Kingsley K;Plopper GE
血管成形术是一种清除血管阻塞的治疗方法，可导致血管壁损伤和随后的异常伤口愈合反应，称为再狭窄。血管平滑肌细胞（VSMC）内衬血管壁响应生长因子和其他刺激释放的损伤细胞。然而，细胞外基质（ECM）可能差异调节VSMC对这些生长因子的反应，如增殖，迁移和粘附。我们以前的报告，低水平表达的ECM分子，层粘连蛋白-5，在正常和受伤的血管表明，层粘连蛋白-5，除了生长因子，可能介导血管损伤后的VSMC反应。为了阐明VSMC对层粘连蛋白-5的反应，我们研究了血小板衍生生长因子（PDGF-BB）在激活丝裂原活化蛋白激酶（MAPK）信号级联中的作用，该信号级联可能是生长因子引发的体外表型变化与ECM之间的联系。使用一个系统的体外试验，我们评估了大鼠血管平滑肌细胞（rVSMC）层粘连蛋白-5板的反应，除了外源性，可溶性PDGF-BB。我们的研究结果表明，虽然层粘连蛋白-5诱导rVSMC的趋触性迁移，但加入PDGF-BB显著增加rVSMC在层粘连蛋白-5上的迁移，这被MAPK抑制剂PD 98059和转化生长因子（TGF-β1）以剂量依赖性方式抑制。此外，PDGF-BB大大降低了rVSMC与层粘连蛋白-5的粘附，这种作用可通过MAPK抑制或加入TGF-β1逆转。此外，这种粘附的减少在另一种ECM底物纤连蛋白上不太显著，并且使用TGF-β1而不是MAPK抑制是可逆的。PDGF-BB也强烈地增加层粘连蛋白-5上的rVSMC增殖，但对铺在纤连蛋白上的rVSMC没有影响。最后，将rVSMC接种于层粘连蛋白-5上并不诱导MAPK活化的增加，而接种于纤连蛋白上或添加可溶性PDGF-BB则诱导MAPK活化的增加。这些结果表明，rVSMC层粘连蛋白-5结合激活整合素依赖的细胞内信号级联，这是不同于那些纤连蛋白或PDGF-BB，导致rVSMC响应更剧烈的MAPK抑制。相反，我们的研究结果表明，纤连蛋白和PDGF-BB可以激活平行，加强细胞内信号级联，收敛在MAPK的激活，因此对MAPK抑制不太敏感。这些结果表明，部分机制来解释rVSMC的行为，包括迁移，粘附和增殖，可能是负责再狭窄的进展的调节。
A treatment to remove vascular blockages, angioplasty, can cause damage to the vessel wall and a subsequent abnormal wound healing response, known as restenosis. Vascular smooth muscle cells (VSMC) lining the vessel wall respond to growth factors and other stimuli released by injured cells. However, the extracellular matrix (ECM) may differentially modulate VSMC responses to these growth factors, such as proliferation, migration and adhesion. Our previous reports of low-level expression of one ECM molecule, laminin-5, in normal and injured vessels suggest that laminin-5, in addition to growth factors, may mediate VSMC response following vascular injury. To elucidate VSMC response on laminin-5 we investigated-the role of platelet-derived growth factor (PDGF-BB) in activating the mitogen-activated protein kinase (MAPK) signaling cascade as a possible link between growth-factor initiated phenotypic changes in vitro and the ECM. Using a system of in vitro assays we assessed rat vascular smooth muscle cell (rVSMC) responses plated on laminin-5 to the addition of exogenous, soluble PDGF-BB. Our results indicate that although laminin-5 induces haptotactic migration of rVSMC, the addition of PDGF-BB significantly increases rVSMC migration on laminin-5, which is inhibited in a dose-dependent manner by the MAPK inhibitor, PD98059, and transforming growth factor (TGF-β1). In addition, PDGF-BB greatly reduces rVSMC adhesion to laminin-5, an effect that is reversible by MAPK inhibition or the addition of TGF-β1. In addition, this reduction in adhesion is less significant on another ECM substrate, fibronectin and is reversible using TGF-β1 but not MAPK inhibition. PDGF-BB also strongly increased rVSMC proliferation on laminin-5, but had no effect on rVSMC plated on fibronectin. Finally, plating rVSMC on laminin-5 did not induce an increase in MAPK activation, while plating on fibronectin or the addition of soluble PDGF-BB did. These results suggest that rVSMC binding to laminin-5 activates integrin-dependent intracellular signaling cascades that are different from those of fibronectin or PDGF-BB, causing rVSMC to respond more acutely to the inhibition of MAPK. In contrast, our results suggest that fibronectin and PDGF-BB may activate parallel, reinforcing intracellular signaling cascades that converge in the activation of MAPK and are therefore less sensitive to MAPK inhibition. These results suggest a partial mechanism to explain the regulation of rVSMC behaviors, including migration, adhesion, and proliferation that may be responsible for the progression of restenosis.