Novel Mechanisms of Oxidative Stress Response in Heart Failure

心力衰竭氧化应激反应的新机制 大量文献表明氧化应激与终末期心力衰竭相关。心肌 局部缺血或梗塞是心力衰竭的最常见原因，其难以治疗且管理成本高， 而且死亡率很高心肌中氧化剂清除或损伤修复系统的缺陷可能 可以解释心力衰竭的进展在细胞水平，低至轻度水平的氧化应激激活Nrf 2 转录因子来开启抗氧化和解毒基因的表达。我们发现， novo Nrf 2蛋白翻译是氧化应激下Nrf 2活化的重要机制。如何 当心肌细胞遇到氧化应激时，某些蛋白质，如Nrf 2，可以选择性地翻译 仍然是未知的。当使用基于蛋白质组学的定量LC-MS/MS研究核糖体时， 我们最近发现YTHD 2，一种含有N6甲基腺苷（m6 A）结合蛋白的YTH结构域， 在氧化应激过程中增加了与核糖体的联系。我们发现YTHD 2增加了 结合Nrf 2 mRNA，并检测到氧化应激下Nrf 2 mRNA中m6 A的增加。敲除 YTHD 2阻断氧化剂诱导Nrf 2蛋白。这些数据使我们假设YTHD 2的阅读 Nrf 2 5'非翻译区（5' UTR）中的m6 A充当从头Nrf 2蛋白翻译的通行证 在氧化应激下。Nrf 2蛋白翻译机制的缺失可能有助于终末期 心衰目的1将测试氧化应激引起Nrf 2 mRNA在特定位点的甲基化和m6 A 由于胃L3甲基化酶的激活而引起的景观变化。目标2将测试YTHD 2结合是否会导致 Nrf 2 5 '非翻译区构象变化与Nrf 2蛋白翻译起始复合物的募集 翻译.目的3将证明胁迫诱导的蛋白质翻译机制、受调节的mRNA 甲基化和Nrf 2介导的细胞保护作用。我们的研究将推动 与涉及氧化性细胞中从头蛋白质翻译的RNA甲基化的新发现有关的知识 应激反应该项目将利用心力衰竭患者的转录组数据来验证 实验室研究的发现对真实的人类疾病的影响。

Novel Mechanisms of Oxidative Stress Response in Heart Failure A large volume of literature indicates an association of oxidative stress with end stage heart failure. Myocardial ischemia or infarction is the most common cause of heart failure, which is difficult to treat and costly to manage, and has a high mortality rate. A deficiency in oxidant removal or damage repair systems in the myocardium may explain the progression of heart failure. At the cellular level, low to mild levels of oxidative stress activate Nrf2 transcription factor to turn on the expression of antioxidant and detoxification genes. We have found that de novo Nrf2 protein translation serves as an important mechanism for Nrf2 activation under oxidative stress. How certain proteins, such as Nrf2, can be selectively translated when cardiac cells encounter oxidative stress remains largely unknown. When investigating the ribosomes using quantitative LC-MS/MS based proteomics, we have recently discovered that YTHD2, a YTH domain containing N6 methyladenosine (m6A) binding protein, increased its association with the ribosomes during oxidative stress. We have found that YTHD2 increases the binding to Nrf2 mRNA and have detected an increase of m6A in Nrf2 mRNA with oxidative stress. Knocking out YTHD2 blocked oxidants from inducing Nrf2 protein. These data lead us to hypothesize that YTHD2 reading of m6A in the Nrf2 5’ untranslated region (5’UTR) serves as a passport for de novo Nrf2 protein translation under oxidative stress. The loss of Nrf2 protein translation mechanisms may contribute to end stage heart failure. Aim 1 will test that oxidative stress causes Nrf2 mRNA methylation at specific sites and m6A landscape change due to activation of METTL3 methylase. Aim 2 will test whether YTHD2 binding causes a Nrf2 5’UTR conformation change and recruitment of a translation initiation complex for de novo Nrf2 protein translation. Aim 3 will demonstrate the losses of stress induced protein translation machinery, regulated mRNA methylation, and Nrf2 mediated cytoprotection in end stage heart failure patients. Our study will advance the knowledge pertaining to a novel discovery involving RNA methylation for de novo protein translation in oxidative stress response. This project will utilize transcriptomic data from heart failure patients to validate mechanistic findings from laboratory research for implications in real life human disease.