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）的病理生理学起源是由替代坏死心肌细胞的修复性纤维化或瘢痕形成引起的。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核细胞（PBMC）非侵入性获得将有助于识别风险。在解决这些目标，我们使用我们建立的模型HHD引起的醛固酮/盐治疗（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，其中细胞的改变的氧化还原状态植根于甲状旁腺激素（PTH）介导的细胞内Ca 2+超载，包括心肌细胞和线粒体和PBMC，并且其中活性氧（ROS）的产生速率超过其通过内源性抗氧化剂防御的解毒速率。这种2C+-α依赖的氧化应激诱导促进线粒体通透性转换孔（mPTP）的开放，最终导致坏死。这种促氧化状态可以通过同时升高的胞质和线粒体2 Z + n作为抗氧化剂来平衡。我们推测，亲和抗氧化剂之间的不平衡是密不可分的耦合失调的Ca 2+和Zn 2+。线粒体是ROS的主要来源。目标一：确定细胞内C ~（2+）α超载引起的氧化应激的细胞和分子起源以及线粒体内Ca ~（2+）蓄积、氧化应激和mPTP开放在导致坏死的信号转导通路中的作用，并将心脏组织及其心肌细胞和线粒体与PBMCW进行比较。并抑制mPTP。通过增加[Zn 2 +]i来防止坏死，这会诱导其传感器，金属响应转录因子（MTF）-1及其调节的抗氧化剂基因。这种“解偶联疗法”包括：Zn 4SO补充剂; PDTC，一种Zn 2+离子载体;或ZnSO 4加一种锌。目标二：探索由细胞内[Zn 2 +]i增加引起的信号转导抗氧化途径，以及由硫酸锌、PDTC、或硫酸锌与EDTA促进的信号转导抗氧化途径，沿着MTF-1调节的抗氧化防御的作用，所述抗氧化防御在心肌细胞中导致抗氧化、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。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。我们在整个目标#1和2中收获PBMC，以寻找风险、损伤和对干预的反应的新的替代生物标志物。目标3：i）鉴定PBMC转录组和蛋白质组的主要组分，其具有促炎心脏表型的分子模拟，包括其线粒体蛋白质组，和ii）阐明可用作HHD临床前和病理阶段期间风险预测的非侵入性生物标志物的特异性途径候选物。 公共卫生相关性：心力衰竭是一个主要的健康问题。高血压性心脏病（HHD）是导致心脏作为肌肉泵衰竭的主要因素，涉及与纤维化相关的心肌不良结构重塑。我们的目的是更好地了解导致纤维化出现的机制，从而确定HHD的风险和预防。

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.