Calcium/Calmodulin Activated Kinases in Smooth Muscle

描述(由申请人提供)：血管平滑肌(VSM)细胞在发育、伤口愈合、血管生成过程中发生迁移和增殖，并有助于血管疾病的进展。已知钙信号调节细胞的增殖和运动，尽管这一知识尚未很好地整合到分子模型中，部分原因是缺乏对钙依赖的效应机制和靶点的了解。由这笔赠款资助的正在进行的工作主要集中在一个主要的钙信号效应器的结构和功能上，即多功能钙/钙调蛋白依赖的蛋白激酶II(CaMKII)。VSM细胞的迁移和增殖是“合成表型”细胞的特性，这些细胞没有获得或失去分化的收缩蛋白标志物和功能。VSM在分化的收缩和增殖/迁移状态之间的表型调节具有相当大的兴趣和临床重要性，但尚不完全清楚。一个新的概念，与过去资金时期的结果一致，是疾病或损伤诱导的钙信号机制和动力学的变化有助于促进血管壁重构的迁移/增殖性VSM表型的发展。这次更新的总体目标是测试钙信号通过特定的CaMKII异构体，调节VSM基因转录，是VSM表型的决定因素的概念。这一概念将通过追求三个目标来检验：1.我们将检验CaMKII调节合成表型VSM中的辅助抑制因子HDAC4和HDAC5的假设。转录激活剂MEF2将被测试为CaMKII/HDAC4，5依赖的影响基因转录的靶标。CaMKII亚型与这一调控通路的偶联特异性有待测试。2.)将评估CaMKII同工酶作为转录抑制因子REST/NRSF在VSM中表达和活性的调节功能，并将测试HDAC4/5作为中介。3.)以大鼠颈动脉球囊损伤为模型，研究CaMKII对HDAC4/5和REST的调节在调节VSM表型和血管重塑中的作用。通过阐明CaMKII亚型调节在血管损伤中的功能后果，这些研究结果有望为深入了解血管平滑肌细胞表型调控的机制以及钙信号和一个重要的钙依赖多功能蛋白激酶调节血管平滑肌细胞功能并参与血管疾病的机制(S)提供帮助。公共卫生相关性：血管平滑肌(VSM)细胞的增殖和迁移与动脉粥样硬化、癌症血管生成以及与再狭窄或移植血管病变相关的内膜增生等病理事件有关，所有这些在西方社会都很普遍。通过阐明CaMKII亚型调控转录抑制因子、IIa类HDACs和REST的机制和功能，我们期望对钙信号调节VSM细胞表型和功能的机制有新的认识。对这些机制的了解可以为旨在控制血管疾病和再狭窄的治疗提供新的靶点。

DESCRIPTION (provided by applicant): Migration and proliferation of vascular smooth muscle (VSM) cells occurs during development, wound healing, angiogenesis, and contributes to the progression of vascular disease. Ca2+ signals are known to regulate cell proliferation and motility, although this knowledge has not been well integrated into molecular models, due in part to lack of insight into Ca2+-dependent effector mechanisms and targets. Ongoing work funded by this grant has focused on the structure and function of one major Ca2+ signal effector, namely multifunctional Ca2+/calmodulin-dependent protein kinase II (CaMKII). VSM cell migration and proliferation are properties of "synthetic phenotype" cells that have not acquired, or have lost, differentiated contractile protein markers and function. VSM phenotype modulation between differentiated contractile and proliferative/migratory states are of considerable interest and clinical importance, but are incompletely understood. An emerging concept, consistent with results from the past funding period, is that disease- or injury-induced changes in Ca2+ signaling mechanisms and dynamics contributes to development of the migratory/proliferative VSM phenotype promoting vascular wall remodeling. The overall objective of this renewal is to test the concept that Ca2+ signaling via specific CaMKII isoforms, regulates VSM gene transcription and is a determinant of VSM phenotype. This concept will be tested by pursuing three aims: 1.) We will test the hypothesis that CaMKII regulates the co-repressors HDAC4 and HDAC5 in synthetic phenotype VSM. The transcription activator MEF2 will be tested as a CaMKII/HDAC4,5-dependent target affecting gene transcription. CaMKII isoform specificity in coupling to this regulatory pathway be tested. 2.) The function of CaMKII isozymes as regulators of the transcriptional repressor REST/NRSF expression and activity in VSM will be evaluated and HDAC4/5 will be tested as intermediaries. 3.) The function of CaMKII-dependent regulation of HDAC4/5 and REST in regulating VSM phenotype and vascular remodeling will be evaluated in vivo using the balloon-injured rat carotid artery as a model. By elucidating the functional consequences of CaMKII isoform modulation in response to vascular injury, the results of these studies are expected to provide insights into mechanisms underlying phenotypic modulation of VSM cells and mechanism(s) by which Ca2+ signals and a prominent Ca2+-dependent multifunctional protein kinase modulates VSM cell function and contributes to vascular disease. PUBLIC HEALTH RELEVANCE: vascular smooth muscle (VSM) cell proliferation and migration is associated with pathological events such as atherosclerosis, cancer angiogenesis, and intimal hyperplasia associated with restenosis or transplant vasculopathy, all prevalent in Western society. By elucidating the mechanisms and functional consequences of CaMKII isoforms in regulating the transcriptional repressors, class IIa HDACs and REST, we expect to gain new insights into mechanisms by which Ca2+ signals modulate VSM cell phenotype and function. Knowledge of these mechanisms could provide new targets for therapeutics aimed at controlling vascular disease and restenosis.