Ion Channel Regulation Coronary Smooth Muscle Phenotype

越来越明显的是，血管平滑肌中的钙内流是一种强调节剂， 通过钙依赖性转录激活平滑肌（SM）基因调控和表型 因素我们提供的证据表明，L型钙离子内流是必要的组成性表达， 平滑肌特异性分化标志物（SMX：例如SMMHC、SMaA），运动可以增加 冠状动脉平滑肌L型钙通道功能。本建议的总体目标是 确定运动训练限制CSM表型转换的机制， 动脉粥样硬化总的假设是钙内流通过L型电压门控钙通道（L-VGCC） 使CSM稳定在分化的收缩表型中。相反，去分化和 增殖是通过上调中电导K通道（IK）和储存操作的 钙通道（SOC）。运动训练通过维持L-VGCC防止CSM表型转换 活性和随后的SM特异性、钙依赖性基因表达。具体目标是：1） 确定动脉粥样硬化对CSM离子通道功能表达的影响，2）确定 动脉粥样硬化对细胞内钙调节的膜电位，3）确定L-型的影响， VGCC与IK/SOC介导的钙离子内流对钙依赖性转录因子和SMX的影响，以及4） 确定运动训练是否可以防止L型VGCC介导的SMX的丢失。早期和 通过高脂肪、高胆固醇（HFC）饮食或 气囊损伤CSM表型的体外和体内测量将使用分子， 细胞和体内冠状动脉血管造影技术。这项研究将首次提供 冠状动脉离子通道活性和CSM表型转换之间的机械联系。此外，它将 提供了CSM在运动的心脏保护作用中的作用的第一个机制检查。

It is becoming increasingly evident that calcium influx in vascular smooth muscle is a strong modulator of smooth muscle (SM) gene regulation and phenotype via activation of calcium-dependent transcription factors. We provide evidence that L-type calcium influx is necessary for the constitutive expression of smooth muscle-specific differentiation markers (SMX: e.g. SMMHC, SMaA) and that exercise can increase L-type calcium channel function in coronary smooth muscle (CSM). The general aim of this proposal is to determine the mechanism(s) by which exercise training limits CSM phenotype switching during atherosclerosis. The overall hypothesis is that calcium influx via L-type, voltage-gated calcium channels (L-VGCC) stabilizes CSM in a differentiated, contractile phenotype. Conversely, dedifferentiation and proliferation are stimulated by upregulation of intermediate-conductance K channels (IK) and store-operated calcium channels (SOC). Exercise training prevents CSM phenotypic switching by maintaining L-VGCC activity and subsequent SM-specific, calcium-dependent gene expression. The Specific Aims are:1) Determine the effect of atherosclerosis on CSM ion channel functional expression, 2) Determine the effect of atherosclerosis on intracellular calicum regulation by membrane potential, 3) Determine the effect of L-type VGCC- versus IK/SOC-mediated calcium influx on calcium-dependent transcription factors and SMX and 4) Determine whether exercise training can prevent the loss of L-type VGCC-mediated SMX. Early and advanced models of atherosclerosis will be produced in swine by dietary high-fat, high-cholesterol (HFC) or balloon injury. Both in vitro and in vivo measures of CSM phenotype will be determined using molecular, cellular and in vivo coronary angiography techniques. The proposed research will provide the first mechanistic link between coronary ion channel activity and CSM phenotype switching. Furthermore, it will provide the first mechanistic examination of the role of CSM in the cardioprotective effect of exercise.