Effect of tissue plasminogen activator on vascular smooth muscle cells.
Effect of tissue plasminogen activator on vascular smooth muscle cells.
复制标题
组织纤溶酶原激活剂对血管平滑肌细胞的影响。
DOI：
10.1016/j.jvs.2005.05.035
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发表时间：
2005
影响因子：
4.3
通讯作者：
Yu,Hong
中科院分区：
文献类型：
--
作者：
Yang,Zhe;Eton,Darwin;Zheng,Feng;Livingstone,AlanS;Yu,Hong
目的：设计组织型纤溶酶原激活物（tPA）在血管细胞中的过表达，作为减少血管内血栓形成的一种手段；然而，在一些研究中，tPA基因转移增加了体内内膜增生。本研究的目的是确定体外tPA基因转移对平滑肌细胞（SMCs）的影响。方法用tPA基因（SMCs/tPA）逆转录转染人SMCs。结果在不含纤溶酶原的情况下，SMCs/tPA与SMCs在增殖、迁移和形态学上无统计学差异。在纤溶酶原存在时，许多差异变得明显。基质金属蛋白酶-2 （MMP-2）的激活在SMCs/tPA中比SMCs高10倍。这种激活被抑酶蛋白（一种纤溶酶抑制剂）抑制。胶原降解在SMCs/tPA中增加了7倍。纤溶酶原存在时，SMCs/tPA显著收缩。这种表明细胞外基质降解的细胞收缩被抑肽蛋白阻断，并被MMP抑制剂部分抑制。SMC/ tpa条件培养基诱导SMC增殖显著增加。SMCs/tPA通过多孔膜的迁移明显超过未转导的SMCs。结论tPA在SMCs中的过度表达可促进细胞外基质降解，促进细胞增殖和迁移。这种作用是通过纤溶酶介导的，它进一步激活MMP-2。临床相关性：etpa已在临床上作为溶栓剂用于治疗急性血栓性疾病。将tPA基因转移到血管细胞中作为一种基因治疗策略已被提出，以增强纤维蛋白溶解能力，从而抑制血管干预后血栓形成和再狭窄。tPA影响SMC增殖和血管重构的机制尚未完全明确。本研究通过tPA表达升高对血管重构的影响，揭示了溶栓活性与内膜增生之间的关系。这项研究强调了一种被认为有利于血液流动的酶的过度表达可能会通过改变表达这种酶的细胞的生物学特性而潜在地损害血液流动。研究结果对合理设计具有良好通畅性的生物活性移植物具有重要意义。提出了一种新的策略来增强血管表面的溶栓能力而不引起过度的内膜增生。
OBJECTIVEEngineered overexpression of tissue plasminogen activator (tPA) in vascular cells has been proposed as a means to decrease intravascular thrombosis; however, tPA gene transfer has augmented intimal hyperplasia in vivo in some studies. The purpose of this study was to define in vitro the effect of tPA gene transfer on smooth muscle cells (SMCs).METHODSHuman SMCs were retrovirally transduced with the tPA gene (SMCs/tPA).RESULTSIn the absence of plasminogen, no statistical differences in proliferation, migration, and morphology were observed between SMCs/tPA and SMCs. In the presence of plasminogen, many differences became apparent. Matrix metalloproteinase-2 (MMP-2) activation was 10-fold higher in SMCs/tPA than in SMCs. This activation was inhibited by aprotinin, a plasmin inhibitor. Collagen degradation increased sevenfold in SMCs/tPA. SMCs/tPA contracted dramatically in the presence of plasminogen. This cell contraction, indicative of extracellular matrix degradation, was blocked by aprotinin and partially inhibited by MMP inhibitors. SMC/tPA-conditioned medium induced significantly more SMC proliferation. The migration of SMCs/tPA through a porous membrane significantly exceeded untransduced SMCs.CONCLUSIONSOver-expression of tPA in SMCs results in increased extracellular matrix degradation and can promote cell proliferation and migration. This effect is mediated via plasmin, which further activates MMP-2.CLINICAL RELEVANCETPA has been clinically used as a thrombolytic agent in the treatment of acute thrombotic disorders. Transferring the tPA gene into vascular cells as a strategy of gene therapy has been proposed to enhance fibrinolytic capability and therefore inhibit thrombosis and restenosis after vascular interventions. The mechanism(s) by which tPA affects SMC proliferation and vascular remodeling has not been thoroughly characterized. This study unveils the relationship between thrombolytic activity and intimal hyperplasia by showing how the elevated expression of tPA affects the vascular remodeling. This study underscores that the overexpression of an enzyme thought beneficial to blood flow can potentially compromise blood flow by altering the biology of the cell engineered to express it. The results are important to the rational engineering of bioactive grafts with better patency. A new strategy to enhance the thrombolytic ability of a vascular surface without inducing excessive neointimal hyperplasia is proposed.