Nrf2 regulation of oxidative stress in heart failure and extra vesicular communication

项目概要/摘要 尽管在慢性心力衰竭（CHF）的管理方面取得了进展，但它仍然是死亡的主要原因， 世界范围内的发病率。Nrf 2信号的减少与氧化应激介导的 心脏重构和交感神经兴奋在CHF发病机制中的作用。然而，有几个关键的 我们目前对Nrf 2信号失调和串扰的分子机制的认识存在差距， 心脏和大脑之间的联系在这里，我们的长期目标是了解一种独特的机制， Nrf 2信号通过CHF中的器官内和器官间通信受损。在之前的研究中，我们发现 miRNA和细胞外囊泡（EV）可能参与CHF中Nrf 2的失调。EV富集 miRNAs是近年来发现的细胞间通讯调节因子和旁分泌信号介质 在心血管系统的生理和病理过程中。这些发现导致了中央 假设心肌梗死（MI）诱导心肌细胞优先分泌富含miRNA的EV， 细胞进入细胞外空间，在那里EV-miRNA直接有助于增加局部氧化应激 通过细胞间通讯，或循环到中枢神经系统，通过干扰中枢神经系统引起交感神经兴奋， 氧化还原稳态由于Nrf 2信号的减少。我们已经鉴定了几种靶向Nrf 2的miRNAs， 在心肌细胞中选择性上调，并包含在分泌到心肌细胞中的EV中。 细胞外间隙我们还提供了证据表明，心脏来源的EV和Nrf 2靶向miRNA存在于 在大脑的交感神经调节区域。在这一强有力的初步数据的指导下，我们建议追求三个 具体目的：1）确定EV富集的miRNA是否有助于Nrf 2翻译抑制和氧化还原 CHF状态下心脏中通过细胞间通讯的不平衡; 2）为了确定心脏来源的 EV参与器官间通信，特别是心脏和大脑之间的串扰， 3）确定来自CHF动物的循环EV是否转移了CHF的病理生理学改变， 在大脑的交感神经调节区域的表型。这一目标也将评估EV介导的miRNA抑制剂是否 递送（即阿托莫西米）通过抑制Nrf 2和抗氧化剂的减少来减弱CHF表型。 酶信号总的来说，所提出的研究是创新的，因为它追求的是一个新颖的想法， 富含miRNA的EV有助于增加局部水平和远端交感神经系统的氧化应激。 通过破坏CHF状态下的氧化还原稳态，通过EV介导的通信调节大脑的调节区域。 这种新的通讯途径可能有助于解释心肌梗死后交感神经活动如何增加 独立于经典神经通路的状态。将人体组织纳入这些研究将提供 独特的翻译成分，并可能导致新的治疗和干预CHF。

PROJECT SUMMARY/ABSTRACT Despite progress in the management of chronic heart failure (CHF), it remains a leading cause of mortality and morbidity worldwide. A reduction in Nrf2 signaling has been closely associated with oxidative stress-mediated cardiac remodeling and sympathetic excitation in the pathogenesis of CHF. However, there are several critical gaps in our current knowledge of the molecular mechanisms of Nrf2 signaling dysregulation and cross-talk between the heart and brain in CHF. Here our long-term goal is to understand a unique mechanism by which Nrf2 signaling is impaired through intra- and inter-organ communication in CHF. In previous studies we showed the potential involvement of miRNAs and extracellular vesicles (EVs) in Nrf2 dysregulation in CHF. EV-enriched miRNAs have recently emerged as regulators of intercellular communication and paracrine signaling mediators during physiological and pathological processes in the cardiovascular system. These findings led to the central hypothesis that myocardial infarction (MI) induces the preferential secretion of miRNA-enriched EVs from cardiac cells into the extracellular space where EV-miRNAs either directly contribute to increased local oxidative stress via intercellular communication, or circulate to the CNS evoking sympathetic excitation by disrupting central redox homeostasis due to a reduction in Nrf2 signaling. We have identified several miRNAs that target Nrf2 mRNA and are selectively upregulated in cardiac cells and contained in EVs that are secreted into the extracellular space. We also provide evidence that cardiac-derived EVs and Nrf2-targeting miRNAs are present in sympatho-regulatory areas of the brain. Guided by this strong preliminary data, we propose to pursue three Specific Aims: 1) To determine if EV-enriched miRNAs contribute to Nrf2 translational inhibition and redox imbalance through intercellular communication in the heart in the CHF state; 2) To determine if cardiac derived EVs participate in inter-organ communication, especially cross-talk between the heart and brain in the progression of CHF, and 3) To determine if circulating EVs from CHF animals transfer a pathophysiological phenotype in sympatho-regulatory areas of the brain. This aim will also evaluate if EV-mediated miRNA inhibitor delivery (i.e. antagomirs) attenuates the CHF phenotype by inhibition of the decrease in Nrf2 and antioxidant enzyme signaling. Collectively, the proposed research is innovative because it pursues the novel idea that miRNA-enriched EVs contribute to increased oxidative stress at the local level and in remote sympatho- regulatory areas of the brain via EV-mediated communication by disrupting redox homeostasis in the CHF state. This novel communication pathway may help to explain how sympathetic nerve activity increases in the post MI state independent of classical neural pathways. Incorporation of human tissue into these studies will provide a unique translational component and potentially lead to new therapies and interventions in CHF.