REGULATION OF MAP KINASE IN VASCULAR SMOOTH MUSCLE

血管平滑肌细胞（VSMC）肥大是一种特征性的 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）通过刺激蛋白质的增加来调节VSMC质量 合成. 体外培养大鼠主动脉肥大模型的建立 血管平滑肌细胞结构清楚，血管紧张素Ⅱ诱导血管平滑肌细胞肥大生长， 反应-包括蛋白质合成和细胞大小的增加 DNA合成或细胞数量没有变化。 出现 相当大的兴趣在确定机制和细胞 血管紧张素II刺激血管平滑肌细胞肥大的信号通路。先前 研究表明，血管紧张素II激活多种第二信使， 包括Ca 2+、蛋白激酶C（PKC）、酪氨酸激酶和促分裂素 活化蛋白（MAP）激酶。 MAP激酶是细胞增殖的关键介质， 生长，并已被证明可以调节核糖体激酶和启动 蛋白质合成和肥大的关键因素， 增生性生长反应。 我们的初步数据显示， II引起VSMC中MAP激酶的快速Ca 2+依赖性激活。因此，在本发明中， 该建议的主要假设是Ca 2+依赖性MAP激酶 活化是血管紧张素II诱导的VSMC肥大的关键介质。 一 用合成的MEK抑制剂进行的一系列实验将确定 MAP激酶的抑制是否阻断了参与 VSMC蛋白质合成和翻译（通过调节来评估） 翻译起始因子eIF-4F），这些因子对血管紧张素Ⅱ的表达至关重要。 II诱导的肥大性生长反应。 一系列的药理学， 生物化学和分子生物学研究旨在鉴定Ca 2 + MAP激酶途径的依赖性组分（Shc，Ras，Raf）， 血管紧张素Ⅱ激活血管平滑肌细胞。 最后，细胞机制， 将确定Ca 2+调节MAP激酶途径。 这些研究 将集中在钙依赖型PKC和钙调蛋白， PKC的药理学和反义寡核苷酸抑制剂， 钙调素亲和层析。 拟议的调查是 重要性，并将严格检验主要假设。 专门针对以下疾病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 高血压治疗的临床意义， 动脉粥样硬化

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.