Harnessing the Adaptive ER Stress Response in Myocardial Ischemia

利用适应性 ER 应激反应治疗心肌缺血

• 批准号: 9924642
• 负责人: Chris Glembotski
• 金额: $ 2.63万
• 依托单位: SAN DIEGO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9924642
• 关键词: ATF6 gene; Address; Apoptosis; Binding; Calcium; Cardiac; Cardiac Myocytes; Cell Nucleus; Cessation of life; Coupled; Data; Disease; Dose; Endoplasmic Reticulum; Environment; Exhibits; Fostering; Gene Deletion; Gene Transfer; Genes; Genetic Transcription; Goals; Growth Factor; Heart; Heart failure; Heat shock proteins; Hela Cells; Hormone Receptor; Hypoxia; Infarction; Ion Channel; Ischemia; Knockout Mice; Mediating; Mission; Modeling; Molecular; Monitor; Morbidity - disease rate; Mus; Muscle Cells; Mutation; Myocardial Infarction; Myocardial Ischemia; Myocardial dysfunction; Normal Cell; Preparation; Process; Property; Proteins; Public Health; Quality Control; Recovery; Regulation; Research; Response Elements; Signal Transduction; Signaling Protein; Site; Structure; Testing; Therapeutic; Time; United States National Institutes of Health; Wild Type Mouse; base; biological adaptation to stress; cancer cell; cell type; design; effective therapy; endoplasmic reticulum stress; gain of function; heart function; improved; in vivo; innovation; mortality; myocardial damage; neoplastic cell; novel; novel strategies; novel therapeutics; overexpression; protein folding; protein misfolding; small molecule; transcription factor; tumor

Project Summary Myocardial ischemia causes ER stress and potentially lethal ER protein misfolding. The adaptive ER stress response restores ER protein folding and fosters myocyte survival. If this process is not sufficient to restore ER protein folding, the ensuing maladaptive ER stress response leads to myocyte death. To survive the hypoxic environment in tumors, cancer cells have evolved an exaggerated adaptive ER stress response, mediated partly by the transcription factor, ATF6, which is activated by ER stress. Compared to cancer cells, normal cells have relatively little ATF6 and a weak adaptive ER stress response. Our preliminary data showed that ATF6 deletion increased infarct size and decreased function in mouse hearts subjected to myocardial infarction. The objective of the proposed research is to examine the molecular mechanism of ATF6 function in the heart, which will reveal new information needed to develop novel therapies for ischemic heart disease based on harnessing the adaptive ER stress response in the heart. In our previous studies, we were surprised to find that activated ATF6 is rapidly degraded; this degraded-when-active property suggests that strict regulation of the level of ATF6 and the genes it regulates, must have functional significance; however, this significance has not been examined. Our hypotheses are as follows: 1- Endogenous ATF6 adaptively decreases apoptosis and infarct size upon ischemia, which improves post-ischemia myocardial recovery. 2- ATF6 is degraded when active because short-term ATF6 activation is adaptive, while long-term ATF6 activation is maladaptive. 3- Activation of endogenous ATF6 with small molecule activators is adaptive, and because it is reversible, we can regulate dose and time to maximize adaptive and minimize maladaptive effects of ATF6 activation to optimize therapeutic potential. These three hypotheses will be addressed by the following corresponding Specific Aims: 1- To assess the effects of endogenous ATF6 deletion on cardiac structure and function in an MI model of heart failure using ATF6 knockout (KO) mice. 2- To use AAV9-mediated gene transfer of forms of ATF6 that exhibit a range of degraded-when-active properties into ATF6 KO mice, then assess the effects of these forms of ATF6 on cardiac structure and function in an MI model of heart failure. 3- To determine the effects of novel small molecule activators of endogenous ATF6 on the viability and on ER stress signaling, initially in isolated cardiac myocytes and then and in mice, in vivo.

项目摘要 心肌缺血导致ER应激和潜在致命的ER蛋白错误折叠。适应性ER应激 应答恢复ER蛋白折叠并促进肌细胞存活。如果此过程不足以恢复ER 蛋白质折叠，随后的适应不良ER应激反应导致肌细胞死亡。为了在缺氧环境中生存 在肿瘤的环境中，癌细胞已经进化出一种夸大的适应性ER应激反应，介导 部分通过转录因子ATF 6，其被ER应激激活。与癌细胞相比，正常细胞 具有相对较少的ATF 6和弱的适应性ER应激反应。我们的初步数据显示， 缺失增加了心肌梗死小鼠心脏的梗死面积，降低了功能。的 所提出的研究的目的是检查心脏中ATF 6功能的分子机制， 这将揭示开发缺血性心脏病新疗法所需的新信息， 利用心脏中的适应性ER应激反应。在我们之前的研究中，我们惊讶地发现 活化的ATF 6迅速降解;这种活性时降解的特性表明， ATF 6的水平及其调控的基因，必须具有功能意义;然而，这种意义 没有被检查。我们的假设如下：1-内源性ATF 6自适应地减少细胞凋亡， 减少缺血时的梗死面积，从而改善缺血后心肌恢复。2-ATF 6在以下情况下会降解： 因为短期的ATF 6激活是适应性的，而长期的ATF 6激活是适应不良的。3- 用小分子激活剂激活内源性ATF 6是适应性的，并且因为它是可逆的，我们可以 调节剂量和时间，以最大化ATF 6激活的适应性效应和最小化适应不良效应， 治疗潜力这三个假设将通过以下相应的具体目标来解决： 1-评估内源性ATF 6缺失对心肌梗死模型心脏结构和功能的影响， 使用ATF 6敲除（KO）小鼠的心力衰竭。2-为了使用AAV 9介导的ATF 6形式的基因转移， 在ATF 6 KO小鼠中表现出一系列活性时降解的特性，然后评估这些形式的作用 在心力衰竭的MI模型中，ATF 6对心脏结构和功能的影响。3-为了确定小说的影响， 内源性ATF 6的小分子激活剂对活力和ER应激信号传导的影响，最初在分离的 心肌细胞，然后在小鼠体内。