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.

项目概要 心肌缺血会导致内质网应激和潜在致命的内质网蛋白错误折叠。适应性 ER 应激 反应恢复 ER 蛋白折叠并促进肌细胞存活。如果此过程不足以恢复 ER 蛋白质折叠后，随之而来的适应不良的内质网应激反应会导致心肌细胞死亡。为了缺氧生存 在肿瘤环境中，癌细胞已经进化出一种夸张的适应性内质网应激反应，介导 部分是由内质网应激激活的转录因子 ATF6 引起的。与癌细胞相比，正常细胞 ATF6 相对较少，适应性 ER 应激反应较弱。我们的初步数据表明 ATF6 缺失增加了心肌梗塞小鼠心脏的梗塞面积并降低了功能。这 拟议研究的目的是检查 ATF6 在心脏中功能的分子机制， 这将揭示开发缺血性心脏病新疗法所需的新信息 利用心脏的适应性内质网应激反应。在我们之前的研究中，我们惊讶地发现 活化的ATF6迅速降解；这种活跃时退化的特性表明，严格监管 ATF6 的水平及其调节的基因必须具有功能意义；然而，这种意义已经 没有经过检查。我们的假设如下： 1- 内源性 ATF6 适应性地减少细胞凋亡并 缺血时的梗塞面积，从而改善缺血后心肌的恢复。 2- ATF6 降解时 因为短期 ATF6 激活是适应性的，而长期 ATF6 激活是适应不良的。 3- 小分子激活剂对内源性 ATF6 的激活是适应性的，并且由于它是可逆的，我们可以 调节剂量和时间以最大限度地提高 ATF6 激活的适应性并最大限度地减少适应不良的影响，从而优化 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 ATF6 缺失对 MI 模型中心脏结构和功能的影响 使用 ATF6 敲除 (KO) 小鼠进行心力衰竭。 2-使用AAV9介导的ATF6形式的基因转移 在 ATF6 KO 小鼠中表现出一系列活性降解特性，然后评估这些形式的影响 ATF6 对心力衰竭 MI 模型中心脏结构和功能的影响。 3-确定小说的效果 内源性 ATF6 的小分子激活剂对活力和 ER 应激信号的影响，最初是分离的 心肌细胞，然后是小鼠体内。