REGULATION OF MAP KINASE IN VASCULAR SMOOTH MUSCLE

血管平滑肌细胞(VSMC)肥大是其特征 导致血管张力异常的高血压血管特征 和结构。在完整的主动脉中，收缩激动剂血管紧张素II (Ang II)通过刺激蛋白质增加来调节VSMC质量 综合。体外培养大鼠主动脉肥厚模型的建立 血管平滑肌细胞是明确定义的，其中血管紧张素Ⅱ诱导肥大生长 反应~包括蛋白质合成和细胞大小的增加 不改变DNA合成或细胞数量。已经有了 对识别机制和细胞学很感兴趣 Ang II刺激VSMC肥大的信号通路。上一首 研究表明，血管紧张素II激活了多种第二信使， 包括钙离子、蛋白激酶C(PKC)、酪氨酸激酶和丝裂原 激活的蛋白(MAP)激酶。MAPK是细胞的关键调节因子 生长，并已被证明调节核糖体激酶和启动 对蛋白质合成和肥大至关重要的因素 增生性生长反应。我们的初步数据显示，Ang II可引起VSMC内钙离子依赖的MAP激酶的快速激活。因此， 这一提议的主要假设是钙离子依赖的MAPK 激活是血管紧张素转换酶II诱导的VSMC肥大的关键介质。一个 用合成的MEK抑制剂进行的一系列实验将确定 抑制MAP激酶是否阻止涉及的限速步骤 VSMC蛋白质的合成和翻译(通过调节 翻译起始因子eIF-4F)对ANG至关重要 II诱导的肥大生长反应。一系列的药理作用， 生物化学和分子研究旨在识别钙离子 MAP激酶途径的依赖成分(Shc、Ras、Raf)是 被血管紧张素转换酶II激活。最后，细胞机制，通过它 Ca~(2+)对MAP激酶通路的调节作用将被确定。这些研究 将集中于钙依赖形式的PKC和钙调蛋白的使用 PKC和PKC的药理和反义寡核苷酸抑制剂 钙调素亲和层析。拟议的调查包括 根本重要性，并将对主要假设进行批判性检验。 针对特定目标的治疗策略的未来发展 参与VSMC肥大的信号通路可能具有重要的 高血压病治疗中的临床意义 动脉硬化。

Vascular smooth muscle cell (VSMC) hypertrophy is a characteristic feature of hypertensive vessels that contributes to abnormal vessel tone and structure. In intact aorta, the contractile agonist angiotensin II (ang II) regulates VSMC mass by stimulating an increase in protein synthesis. An in vitromodel of hypertrophy using cultured rat aortic VSMC is well defined, in which ang II induces a ~hypertrophic growth response~ consisting of an increase in protein synthesis and cell size without changes in DNA synthesis or cell number. There has been considerable interest in identifying the mechanisms and cellular signaling pathways whereby ang II stimulates VSMC hypertrophy. Previous work has shown that ang II activates a variety of second messengers, including Ca2+, protein kinase C (PKC), tyrosine kinases, and mitogen activated protein (MAP) kinases. MAP kinases are key mediators of cell growth and have been shown to regulate ribosomal kinases and initiation factors that are crucial for protein synthesis and hypertrophic and hyperplastic growth responses. Our preliminary data indicate that ang II causes a rapid Ca2+ dependent activation of MAP kinase in VSMC. Thus, the major hypothesis of this proposal is that Ca2+ -dependent Map kinase activation is a key mediator of ang II-induced VSMC hypertrophy. A series of experiments with a synthetic MEK inhibitor will determine whether inhibition of MAP kinases blocks rate limiting steps involved in VSMC protein synthesis and translation (as assessed by the regulation of the translation initiation factor eIF-4F) that are crucial to the ang II-induced hypertrophic growth response. A series of pharmacological, biochemical and molecular studies are designed to identify Ca2+ dependent components of the MAP kinase pathway (Shc, Ras, Raf) that are activated by ang II in VSMC. Finally, cellular mechanisms, by which Ca2+ regulates the MAP kinase pathway will be determined. These studies will concentrate on Ca2+ -dependent forms of PKC and calmodulin by use of pharmacological and antisense oligonucleotide inhibitors of PKC and calmodulin affinity chromatography. The proposed investigations are of fundamental importance and will critically test the major hypothesis. Future development of therapeutic strategies specifically targeted to signaling pathways involved in VSMC hypertrophy may have important clinical implications in the treatment of hypertension and atherosclerosis.