Variant Determinants of African American Limb Pathology in Peripheral Arterial Disease

摘要 外周动脉疾病（PAD）是由外周动脉的动脉粥样硬化引起的，最常见于 西拉司妥唑是最后一种被批准用于治疗的药物， PAD患者（1999），二十年的试验和临床前测试未能推进治疗。 PAD表现为间歇性跛行（IC;运动时疼痛，休息后缓解）或肢体危象 缺血（CLI;休息时疼痛，伴或不伴组织坏死或坏疽）。尽管CLI不如IC常见，但 具有显著更高的发病率和死亡率; CLI患者具有大截肢或死亡的风险， 一年内接近40%。IC和CLI临床病程的差异以及最近的预处理结果 临床研究提出了有趣的可能性，即IC和CLI代表了不同的表型表现， 同样的疾病过程。我们提出了一个创新的想法：再生和功能健全的骨骼肌 支持缺血性新血管形成和血管成熟-最终导致组织血液的恢复 流动和防止组织损失。我们的提议将直接测试局部肢体缺血细胞的能力 微环境以改变组织结果。我们将探讨人BAG3（Bcl-2相关的BAG3）在人免疫缺陷病毒中的作用。 athanogene 3-一种进化上保守的575个氨基酸的蛋白质），特别是在肢体肌肉中， 患者和小鼠的内皮细胞。BAG3是一种多功能支架蛋白和共伴侣， 在心脏和骨骼肌中的多效性作用。这是一个有前途的遗传候选治疗的发展 1）BAG3突变引起肌原纤维性肌病和扩张性肌纤维性肌病， 2）BAG3变异体存在于患有CLI的非裔美国人（人口统计学）中， 不成比例地受PAD影响-初步数据）和心肌病，以及3） BAG3调节PAD（后肢）临床前模型中的肌肉再生、血管密度和肢体存活 缺血-HLI）。为此，这项提案汇集了临床血管外科医生，骨骼肌生物学家， 他专注于生理结果测量，是一位生物化学家和线粒体生物学家， 询问疾病中线粒体的形式和功能，临床心脏病学家和研究人员，以及翻译 研究骨骼肌对损伤的适应性和内皮细胞生物学的科学家， 无与伦比的人类PAD组织生物库。这一建议的核心假设是， BAG3的变异导致肌病和肌病， 肌肉和内皮细胞，并导致局部肌肉环境不足以支持 脉管系统为此，具体目标是：1）在PAD相关模型中，确定功能链接 缺血性肌病和血管生成之间的联系2)确定Cox6a2表达是否足以挽救 BAG3变体在PAD条件下诱导肌病。3)确定BAG3变异体是否与AA CLI患者结局的种族和差异。

Abstract Peripheral artery disease (PAD) is caused by atherosclerosis of the peripheral arteries, most commonly in the lower extremities, and affects 8-12 million individuals in the U.S. Cilastozol was the last drug approved to treat patients with PAD (1999) and twenty years of trials and pre-clinical testing have failed to advance therapeutics. PAD presents as either intermittent claudication (IC; pain with exertion that is relieved with rest) or critical limb ischemia (CLI; pain at rest with or without tissue necrosis or gangrene). Although less common than IC, CLI carries a substantially higher morbidity and mortality; CLI patients have a risk of major amputation or death that approaches 40% in one year. Differences in the clinical course of IC and CLI together with results of recent pre- clinical studies raise the intriguing possibility that IC and CLI represent distinct phenotypic manifestations of the same disease process. We propose an innovative idea; regenerating and functionally competent skeletal muscle supports ischemic neovascularization and vessel maturation - ultimately leading to the recovery of tissue blood flow and the prevention of tissue loss. Our proposal will directly test the ability of ischemic cells in the local limb microenvironment to alter tissue outcomes. We will interrogate the role of human BAG3 (Bcl-2 associated athanogene 3 - an evolutionarily conserved 575 amino acid protein) specifically in the limb muscle and endothelial cells of patients and mice. BAG3 is a multifunctional scaffolding protein and co-chaperone with pleiotropic effects in heart and skeletal muscle. It is a promising genetic candidate for therapeutic development in PAD for the following reasons: 1) mutations in BAG3 cause muscle myofibrillar myopathy and dilated cardiomyopathy in humans, 2) BAG3 variants exist in both African Americans with CLI (a demographic disproportionately affected by PAD - Preliminary Data) and cardiomyopathy, and 3) a murine coding variant in BAG3 regulates muscle regeneration, vascular density, and limb survival in a pre-clinical model of PAD (hindlimb ischemia-HLI). To that end, this proposal brings together clinical vascular surgeons, a skeletal muscle biologist who focuses on physiologic outcome measures, a biochemist and mitochondrial biologist who focuses on interrogating mitochondrial form and function in disease, a clinical cardiologist and researcher, and a translational scientist who studies skeletal muscle adaptability to injury and endothelial cell biology and has developed an unparalleled biobank of human PAD tissues. The central hypothesis of this proposal states that genetic variants in BAG3 result in myopathy and mitochondriopathy that disrupts communication between muscle and endothelial cells and results in a local muscle environment insufficient to support the vasculature. To that end, the Specific Aims are: 1) In PAD relevant models, determine the functional link between ischemic myopathy and angiogenesis. 2) Determine whether Cox6a2 expression is sufficient to rescue BAG3 variant induced myopathy in PAD conditions. 3) Establish whether BAG3 variants are a link between AA race and differences in CLI patient outcomes.