Urocortin 2 Gene Transfer for Heart Failure with Preserved Ejection Fraction

该提案的重点是为心力衰竭患者开发一种新的治疗方法， 射血分数（HFpEF）。在有症状的HF患者中，一半患有HFpEF，其死亡率为 与HFrEF相似。然而，目前没有延长生命的HFpEF治疗方法， 很少（如果有的话）能可靠地降低HF住院率。我们需要新的疗法来解决这个未满足的问题 医疗需求。心血管基因转移在概念上是治疗HF的有吸引力的方法，但 很难在心脏中以容易和安全的方式获得高产转基因表达 应用是具有挑战性的。然而，我们最近已经证明了静脉注射的有效性。 （静脉注射）递送编码肽尿皮质素2（Ucn 2）的长期表达载体（AAV 8），所述肽 通过其旁分泌/内分泌作用具有良好的心血管作用。在我们目前的退伍军人管理局功绩中 授予我们已经建立了AAV8.Ucn2在两种情况下1次静脉内给药的安全性和有效性。 HFpEF老化和压力超负荷的鼠模型，临床HFpEF的两个危险因素。然而，在这方面， 在临床翻译这种急需的药物之前， 疗法 假设：Ucn2/Ucn3基因转移，通过旁分泌/内分泌效应，将改善心脏功能 通过促肾上腺皮质激素释放激素在两种HFpEF模型（不同物种）中的存活率 受体2（CRHR2）依赖性增强心肌细胞中的Ca 2+处理 目的1：在模型中确定Ucn 2与Ucn 3基因转移的有效性和生存优势 高血压导致的HFpEF（Dahl盐敏感大鼠） 目的2a：确定Ucn2基因转移对老年小鼠左室功能的有益作用是否是 通过CRHR2的心脏靶向缺失消除 目的2b：确定Ucn2基因转移对老年左室的有益作用是否来自于 增强Ca2+处理和增加肌节缩短和延长的速率 目的3：确定连接Ucn 2和Ucn 3肽激活CRHR 2的细胞内机制 在培养的心肌细胞中具有增强的Ca2+处理 这些目标旨在回答关键问题：1）Ucn2基因转移的益处是否会在一个人身上看到？ 第二种HFpEF模型（高血压Dahl盐敏感大鼠）中的第二个物种，它是否会赋予存活率 Ucn3基因转移是否会产生类似的有益效果？这些问题将得到解决 目的1; 2）Ucn2基因转移对心脏CRHR2的有益作用在多大程度上 由于平滑肌中CRHR2的激活和伴随的全身性血管舒张， 血管扩张？我们将通过使用CRHR2的心脏靶向缺失来解决这个问题（目标2）; 3)最后，我们建议通过以下方法绘制CM CRHR2刺激的细胞内途径（机制）： Ucn2/Ucn3与在孤立CM中进行的一系列研究中预测的Ca2+处理增加的关系 (Aim 3）。这些临床前研究，重点是作用机制和有效性， 体内治疗将作为在HFpEF的大型哺乳动物模型中进行的额外研究的接续， 单独资助，并在提交IND申请以启动临床试验后， 我们之前在实验室进行了两次过渡（ClinicalTrials.gov：NCT 00787059和 NCT00346437）。

This proposal focuses on development of a new treatment for patients with heart failure and preserved ejection fraction (HFpEF). Among symptomatic patients with HF, half have HFpEF, and their mortality is similar to those with HFrEF. However, there are currently no treatments for HFpEF that prolong life, and few (if any) that reliably reduce HF hospitalization rates. We need new therapies to address this unmet medical need. Cardiovascular gene transfer is conceptually an attractive method for treating HF, but difficulty in obtaining high yield transgene expression in the heart in a manner that can be easily and safely applied has been challenging. However, we recently have demonstrated the effectiveness of intravenous (i.v.) delivery of a long-term expression vector (AAV8) encoding a peptide, urocortin 2 (Ucn2), which possesses favorable cardiovascular effects through its paracrine/endocrine actions. In our current VA Merit grant we have established the safety and efficacy of a 1-time i.v. administration of AAV8.Ucn2 in two murine models of HFpEF—aging and pressure overload, two risk factors for clinical HFpEF. However, there are several important issues that must be resolved prior to clinical translation of this much-needed therapy. Hypothesis: Ucn2/Ucn3 gene transfer, through paracrine/endocrine effects, will improve cardiac function and survival in two models of HFpEF (in different species) via corticotropin releasing hormone receptor 2 (CRHR2)-dependent enhancement of Ca2+ handling in cardiac myocytes Aim 1: To determine the effectiveness and survival advantage of Ucn2 vs Ucn3 gene transfer in a model of HFpEF due to hypertension (Dahl Salt-Sensitive Rat) Aim 2a: To determine if the beneficial effects of Ucn2 gene transfer on LV function in aged mice are abrogated by cardiac-targeted deletion of CRHR2 Aim 2b: To determine whether the beneficial effects of Ucn2 gene transfer on the aged LV result from enhanced Ca2+ handling and increased rates of sarcomere shortening and lengthening Aim 3: To determine the intracellular mechanisms linking Ucn2 and Ucn3 peptide activation of CRHR2 with enhanced Ca2+ handling in cultured cardiac myocytes These Aims are designed to answer key questions: 1) Will the benefits of Ucn2 gene transfer be seen in a second species in a second model of HFpEF (hypertensive Dahl Salt-Sensitive rats), will it confer a survival advantage, and will Ucn3 gene transfer have similar beneficial effects? These questions will be addressed in Aim 1; 2) To what degree are the beneficial effects of Ucn2 gene transfer due to cardiac CRHR2 activation vs systemic vasodilation due to activation of CRHR2 in smooth muscle and attendant systemic vasodilation? We will address this question by using cardiac-targeted deletion of CRHR2 (Aim 2); 3) Finally, we propose to map the intracellular pathways (mechanisms) from CM CRHR2 stimulation by Ucn2/Ucn3 to the predicted increase in Ca2+ handling in a series of studies conducted in isolated CMs (Aim 3). These preclinical studies, which are focused on mechanism of action and effectiveness of treatment in vivo will serve as a segue for an additional study in a large mammalian model of HFpEF under separate funding, and subsequently to the filing of an IND application for the initiation of a clinical trial, a transition we have made in our laboratory twice previously (ClinicalTrials.gov: NCT00787059 and NCT00346437).