Big MAP Kinase 1-Cx 43 Signaling in Ischemia Injury

缺血损伤中的大 MAP 激酶 1-Cx 43 信​​号转导

• 批准号: 6926479
• 负责人: JAY YANG
• 金额: $ 40.08万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6926479
• 关键词: biological signal transduction; calcium flux; calpain; cytoprotection; gap junctions; genetically modified animals; immunoprecipitation; ischemic preconditioning; laboratory mouse; mitogen activated protein kinase; myocardial ischemia /hypoxia; phosphorylation; protein structure function; reperfusion; tissue /cell culture; western blottings

DESCRIPTION (provided by applicant): Ca2+ overload is a major cause of myocardial cell damage and cardiac dysfunction in ischemic heart diseases. Studies with gap junction coupling inhibitors and connexin (Cx) 43 knock out mice suggest that Cx43 is important in regulating ischemia/ reperfusion (IR)- induced cellular Ca2+ overload. Cx43 gap junction coupling is regulated by several kinases including mitogen-activated-protein (MAP) kinases. Since ischemic preconditioning improves the recovery of cardiac function after IR-injury and also activates Big- MAPK 1 (BMK1), a member of MARK, we hypothesized that activation of BMK1 induced by preconditioning phosphorylates Cx43, decreases gap junction coupling, and reduces ischemia/ reperfusion-induced cellular Ca2+ overload. Key data in support of our hypothesis include: 1} BMK1 phosphorylates and associates with Cx43, and leads to gap junction uncoupling, 2) Cx43 phosphorylation is increased in cardiac-specific transgenic mice expressing the constitutively active form of the upstream kinase MEK5 (CA-MEK5) which specifically activates BMK1, 3) CA-MEK5 transgenic hearts exhibit a profoundly accelerated recovery of pump function after IR-injury in a Langendorff model. We will study the role of BMK1 and Cx43 phosphorylation in post-ischemic cardiac dysfunction with the following specific aims: Aim 1: Define the role of BMK1 in Cx43 phosphorylation and subsequent Cx43 gap junction uncoupling. Aim 2: Define the role of BMK1 in Cx43 phosphorylation and the effect of Cx43 phosphorylation on IR- induced Ca2+ overload, subsequent calpain activity, and mitochondrial dysfunction. Aim 3: Determine the role of BMK1 and subsequent Cx43 phosphorylation in IR-injury, in vivo, and Aim 4: Investigate the role of BMK1-Cx43 signaling in chemical preconditioning. The broad-based experimental approach should allow us to conclude the importance of BMK1-Cx43 signaling in IR-injury. The long-range goal of this line of investigation is to discover a novel therapeutic strategy for reducing IR-injury.

描述(由申请人提供)：钙超载是缺血性心脏病心肌细胞损伤和心功能不全的主要原因。对缝隙连接偶联抑制剂和连接蛋白(Cx)43基因敲除小鼠的研究表明，Cx43在调节缺血/再灌注(IR)诱导的细胞钙超载中起重要作用。Cx43缝隙连接偶联受包括丝裂原活化蛋白(MAP)在内的几种激酶的调节。由于缺血预适应促进了IR损伤后心功能的恢复，并激活了MARK成员Big-MAPK1(BMK1)，我们推测，预适应诱导的BMK1激活使Cx43磷酸化，减少缝隙连接偶联，从而减轻缺血/再灌注引起的细胞内钙超载。支持我们假设的关键数据包括：1)BMK1被磷酸化并与Cx43相关，并导致缝隙连接解偶联；2)在心脏特异表达上游活性形式的MEK5(CA-MEK5)的转基因小鼠中，Cx43的磷酸化水平增加，CA-MEK5特异地激活了BMK1；3)在Langendorff模型中，转CA-MEK5基因的心脏在IR损伤后表现出显著的加速泵功能恢复。我们将研究BMK1和Cx43磷酸化在缺血后心功能不全中的作用，具体目的如下：目的1：明确BMK1在Cx43磷酸化和随后的Cx43缝隙连接解偶联中的作用。目的2：明确BMK1在Cx43磷酸化中的作用，以及Cx43磷酸化在IR诱导的钙超载、随后的钙蛋白酶活性和线粒体功能障碍中的作用。目的3：在体内研究BMK1及其随后的Cx43磷酸化在IR损伤中的作用，目的4：探讨BMK1-Cx43信号在化学预适应中的作用。广泛的实验方法应该允许我们得出BMK1-Cx43信号在IR损伤中的重要性。这项研究的长期目标是发现一种减少IR损伤的新的治疗策略。