Unfolded Protein Response and Arrhythmias

项目摘要 膜电流改变与心源性猝死有关。缺血性心肌病(ICM) 造成了四分之三的死亡。在初步数据中，我们表明：(I)福利，展开的一部分 蛋白反应(UPR)，在小鼠心肌梗死(MI)模型中被早期和持续激活，(II) 心肌梗死后抑制PERK可减少猝死，减少自发性、非持续性室性心动过速 (VT)，缩短QTC间期，并缩短动作电位时程(Apd)，而不会产生不良后果 收缩功能，(Iii)UPR激活可延长动作电位时程，减缓AP上行，并改变部分但不是全部离子 (4)抑制PERK可部分逆转动作电位时程延长和部分离子通道下调。 假设：我们假设PERK和其他UPR感受器的激活降低了mRNA的丰度和 心脏离子通道的蛋白质翻译。这导致了电流改变、动作电位时程延长和 ICM患者发生心律失常的风险增加。抑制PERK或其他UPR效应器可以防止一些 改建。在体内，抑制PERK将在ICM中起到抗心律失常的作用，部分是通过改善传导速度和 减少警局。 具体目标： 目的1：确定PERK抑制能在多大程度上阻止动作电位时程延长 与ICM相关的重构和心律失常风险。为了达到这个目的，将在小鼠身上诱导ICM。警察局， 对服用和不服用药物的小鼠的电重构和心律失常风险进行比较 在梗死后立即或在3周后开始抑制PERK，以测试预防和治疗策略。 结果将与PERK(心脏特异性PERK基因敲除(KO))的遗传抑制和结果进行比较 在人类ICM中。 目的2：确定PERK能在多大程度上促进动作电位时程延长及其改变 离子通道。用人诱导多能干细胞来源的心肌细胞(hiPSC-CMS)激活 UPR，我们将确定哪些其他离子通道被UPR和PERK激活改变并负责 以延长警局的期限。 目的3：研究UPR的IRE1和ATF6分支是否参与动作电位时程延长 以及离子通道的改变。利用HIPSC-CMS激活小麦Ire_1和ATF_6分支 UPR，我们将确定这两个分支的激活是否有助于AP的变化和 心脏离子通道下调。

Project Summary Altered membrane currents are implicated in sudden cardiac death. Ischemic cardiomyopathy (ICM) is responsible for three quarters of these deaths. In preliminary data, we show that (i) PERK, part of the unfolded protein response (UPR), is activated early and persistently in a mouse myocardial infarct (MI) model, (ii) inhibiting PERK after MI reduces sudden death, reduces spontaneous, nonsustained ventricular tachycardia (VT), reduces QTc interval, and reduces action potential duration (APD) without negative consequences to contractile function, (iii) the UPR activation prolongs APD, slows AP upstroke, and alters some but not all ion channels, and (iv) PERK inhibition partially reversed APD prolongation and some ion channel downregulations. Hypothesis: We hypothesize that activation of PERK and other UPR sensors reduce mRNA abundance and protein translation of cardiac ion channels. This contributes to current alterations, APD prolongation, and increased arrhythmic risk in ICM. Inhibition of PERK or other UPR effectors can prevent some of the remodeling. In vivo, PERK inhibition will be antiarrhythmic in ICM, in part, by improving conduction velocity and reducing APD. Specific aims: Aim 1: Determine the extent to which PERK inhibition can prevent APD prolongation, electrical remodeling and arrhythmic risk associated with ICM. In this aim, ICM will be induced in mice. APD, electrical remodeling and arrhythmic risk will be compared between mice with and without pharmacological inhibition of PERK starting immediate after infarct or at 3 weeks to test prevention versus treatment strategies. Results will be compared to genetic inhibition of PERK (cardiac specific PERK-knockout (KO)) and to findings in human ICM. Aim 2: Determine the extent to which PERK can contribute to APD prolongation and the alterations of ion channels. Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) with activated UPR, we will determine which other ion channels are altered by UPR and PERK activation and are responsible for APD prolongation. Aim 3: Investigate whether the IRE1 and ATF6 branches of the UPR contribute to APD prolongation and the alterations of ion channels. Using hiPSC-CMs and activating the IRE1 and ATF6 branches of UPR, we will determine whether activation of these two branches contributes to AP changes and downregulation of cardiac ion channels.