Regulatory Mechanisms of Oxidative Stress in Hypertensive Heart Disease

描述（由申请人提供）：高血压性心脏病（HHD）有其病理生理起源，源于替代坏死心肌细胞的修复性纤维化或瘢痕形成。了解心肌细胞坏死背后的病理生物学将导致HHD的预防，而预测坏死的生物标志物的可用性和从外周血单个核细胞（PBMC）中获得的非侵入性将有助于识别风险。为了实现这些目标，我们使用我们建立的醛固酮/盐治疗引起的HHD模型（ALDOST），并利用其临床前（第1周）和病理（第4周）阶段。中心假设：在HHD中，第4周的纤维化是由于氧化应激诱导的心肌细胞坏死，其中细胞氧化还原状态的改变源于甲状旁腺激素（PTH）介导的细胞内Ca2+超载，包括心肌细胞、线粒体和PBMC，其中活性氧（ROS）的产生速度超过了内源性抗氧化防御的解毒速度。这种2C+依赖性氧化应激诱导促进线粒体通透性过渡孔（mPTP）的开放，最终导致坏死。这种促氧化状态可以通过细胞质和线粒体中作为抗氧化剂的2Z+的同时增加来抵消。我们假设促氧化剂和抗氧化剂之间的不平衡与Ca2+和Zn2+的耦合不平衡密不可分。线粒体是ROS的主要来源。目的1：确定细胞内C2+a超载引起的氧化应激的细胞和分子起源，以及线粒体内Ca2+积累、氧化应激和mPTP开放在导致坏死的信号转导途径中的作用，并将心脏组织及其心肌细胞和线粒体与PBMCW进行比较。e使用线粒体靶向试剂：b锁定2+Cau信使；作为抗氧化剂；抑制mPTP。坏死是通过增加的[Zn2+]i来防止的，它诱导了它的传感器，金属反应转录因子(MTF)-1和它所调节的抗氧化基因。这种“解偶联疗法”包括：补充zn4so；PDTC，一种Zn2+离子载体；或者ZnSO4加一份氯地平。目的2：探索细胞内[Zn2+]i增加所引发的信号转导抗氧化途径，并由ZnSO4、PDTC或ZnSO4与氨氯地平共同促进，以及MTF-1调节的抗氧化防御的作用，最终导致心肌细胞的抗氧化、抗炎表型，并将心脏组织及其心肌细胞和线粒体与PBMC进行比较。在ALDOST期间，PBMC与心肌细胞和线粒体具有共同的病理生理反应和上调的基因网络。我们在目标1和目标2中收集PBMC，以寻找风险、损伤和干预反应的新型替代生物标志物。目标3:1)确定PBMC转录组和蛋白质组的主要成分与促炎心脏表型具有分子相似性，包括其线粒体蛋白质组；2)阐明可作为HHD临床前和病理阶段风险预测的非侵入性生物标志物的特定途径候选物。

DESCRIPTION (provided by applicant): Hypertensive heart disease (HHD) has its pathophysiologic origins arising from the reparative fibrosis, or scarring, that replaces necrotic cardiomyocytes. Understanding the pathobiology behind cardiomyocyte necrosis will lead to the prevention of HHD while the availability of biomarkers predictive of necrosis and obtained noninvasively from peripheral blood mononuclear cells (PBMC) will aid in identification of risk. In addressing these objectives we use our established model of HHD provoked by aldosterone/salt treatment (ALDOST) and exploit its preclinical (wk 1) and pathologic (wk 4) stages. Central hypothesis: in HHD, fibrosis at wk 4 is due to oxidative stress- induced cardiomyocyte necrosis, where the cell's altered redox state is rooted in parathyroid hormone (PTH)- mediated intracellular Ca2+ overloading, including cardiac myocytes and mitochondria and PBMC, and where the rate of reactive oxygen species (ROS) generation overwhelms the rate of their detoxification by endogenous antioxidant defenses. This 2C+-adependent induction of oxidative stress promotes the opening of the mitochondrial permeability transition pore (mPTP) to culminate i n necrosis. This prooxidant state can be counterbalanced by the contemporaneous rise in cytosolic and mitochondrial 2Z+nserving as antioxidant. We hypothesize the dysequilibrium between pro- and antioxidant is inextricably linked to the coupled dyshomeostasis of Ca2+ and Zn2+. Mitochondria are the major source of ROS. Aim #1: to determine the cellular and molecular origins of oxidative stress arising from intracellular C2+a overloading and the role of intra mitochondrial Ca2+ accumulation, oxidative stress and mPTP opening in the signal-transduction pathway leading to necrosis and to compare heart tissue and its cardiac myocytes and mitochondria with PBMCW.e use mitochondria-targeted reagents: to b lock the 2+Cau niporter; t o serve as antioxidant; and to inhibit mPTP. Necrosis is prevented by increased [Zn2+]i, which induces its sensor, metal-responsive transcription factor (MTF)-1 and the antioxidant genes it regulates. Such "uncoupling therapy" includes: Zn4SOsupplement; PDTC, a Zn2+ ionophore; or ZnSO4 plus a mlodipine. Aim # 2: to explore the signal-transduction antioxidant pathway invoked by increased intracellular [Zn2+]i and promoted by ZnSO4, PDTC, or ZnSO4 with amlodipine, along with the role of MTF-1 regulated antioxidant defenses that eventuate in an antioxidant, anti-inflammatory phenotype in cardiac myocytes and to compare heart tissue and its cardiomyocytes and mitochondria with PBMC. PBMC share common pathophysiologic responses and upregulated gene networks with cardiac myocytes and mitochondria during ALDOST. We harvest PBMC throughout Aims #1 and 2 in search of novel surrogate biomarkers of risk, injury and response to intervention. Aim #3: i) to identify major components of the PBMC transcriptome and proteome having molecular mimicry with the pro inflammatory cardiac phenotype, including its mitochondrial proteome, and ii) to elucidate specific pathway candidates that could serve as noninvasive biomarkers predictive of risk during preclinical and pathologic stages of HHD. PUBLIC HEALTH RELEVANCE: Heart failure is a major health problem. Hypertensive heart disease (HHD), a major factor contributing to the heart's failure as a muscular pump, involves an adverse structural remodeling of myocardium related to fibrosis. Our aim is to better understand mechanisms contributing to the appearance of fibrosis and to thereby identify risk and prevention of HHD.