Hu Y, Cheng L, Hochleitner B W, Xu Q
Institute for Biomedical Aging Research, Austrian Academy of Sciences, Innsbruck, Austria.
Arterioscler Thromb Vasc Biol. 1997 Nov;17(11):2808-16. doi: 10.1161/01.atv.17.11.2808.
Smooth muscle cell proliferation is a key event in neointimal formation after balloon angioplasty. The molecular signals that mediate this process have yet to be identified. Mitogen-activated protein (MAP) kinases are thought to play a pivotal role in transmitting transmembrane signals required for cell proliferation in vitro. The present studies were designed to investigate whether the signal transduction pathways of MAP kinases were involved in the development of restenosis in the injured arteries. Rat carotid arteries were isolated at various time points after balloon injury, and activities of MAP kinases, including extracellular signal-regulated kinases (ERK), and stress activated protein kinases (SAPK)/c-Jun N-terminal protein kinases (JNK), were determined in protein extracts of the vasculature using protein kinase assay and Western blot analysis. After balloon angioplasty, ERK2 and JNK1 activities in the vessel wall increased rapidly, reached a high level in 5 minutes and maintained for 1 hour. A sustained increase in ERK2 kinase activity was observed over the next 7 days in the arterial wall and 14 days in neointima after injury. In contrast, opposite and uninjured arteries did not show significant changes in these kinase activities. Concomitantly, Western blot analysis confirmed that the ERK2 kinase in the injured vessels was indeed activated or phosphorylated, showing a slowly migrating species of a 42-kDa protein containing phosphorylated tyrosine. Kinase activation is followed by an increase in c-fos and c-jun gene expression and enhanced activator protein 1 (AP-1) DNA-binding activity. Thus, balloon injury rapidly activates the MAP kinases in rat carotid arteries. These kinase activations may be crucial in mediating smooth muscle cell proliferation in response to vascular angioplasty.
平滑肌细胞增殖是球囊血管成形术后新生内膜形成的关键事件。介导这一过程的分子信号尚未明确。丝裂原活化蛋白（MAP）激酶被认为在体外传递细胞增殖所需的跨膜信号中起关键作用。本研究旨在探讨MAP激酶的信号转导途径是否参与损伤动脉再狭窄的发生发展。在球囊损伤后的不同时间点分离大鼠颈动脉，使用蛋白激酶测定法和蛋白质印迹分析法测定脉管系统蛋白提取物中MAP激酶的活性，包括细胞外信号调节激酶（ERK）和应激激活蛋白激酶（SAPK）/c-Jun氨基末端蛋白激酶（JNK）。球囊血管成形术后，血管壁中的ERK2和JNK1活性迅速增加，在5分钟时达到高水平并维持1小时。在损伤后的接下来7天内，动脉壁中观察到ERK2激酶活性持续增加，在新生内膜中持续14天。相比之下，对侧未损伤动脉的这些激酶活性没有显著变化。同时，蛋白质印迹分析证实损伤血管中的ERK2激酶确实被激活或磷酸化，显示出一种含有磷酸化酪氨酸的42 kDa蛋白的缓慢迁移条带。激酶激活后，c-fos和c-jun基因表达增加，激活蛋白1（AP-1）的DNA结合活性增强。因此，球囊损伤可迅速激活大鼠颈动脉中的MAP激酶。这些激酶激活可能在介导血管成形术后平滑肌细胞增殖中起关键作用。
