Skeletal Muscle and Vascular Remodeling in Peripheral Artery Disease

周围动脉疾病中的骨骼肌和血管重塑

基本信息

批准号：
8903576
负责人：
Christopher D Kontos
金额：
$ 51.64万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8903576
关键词：
Ablation Accounting Acute Affect Benign Blood Vessels Cell Count Cell Differentiation process Cell Proliferation Cell physiology Cells Cessation of life Clinical Development Differentiation Antigens Disease Endothelial Cells Event Genes Genetic Predisposition to Disease Goals Growth Health Human Human Genetics In Vitro Inbred BALB C Mice Individual Injury Intermittent Claudication Ischemia Lead Limb structure Mediating Modeling Morphology Mouse Strains Mus Muscle Muscle Cells Muscle Fibers Muscle function Natural regeneration Necrosis PECAM1 gene Patients Pattern Perfusion Peripheral arterial disease Phenotype Physiological Population Predisposition Process Receptor Signaling Recombinant adeno-associated virus (rAAV)Research Resistance Risk Role Sampling Signal Transduction Skeletal Muscle Stem cells Syndrome Testing Tissues Vascular Endothelial Growth Factor Receptor Vascular Endothelial Growth Factor Receptor-1 Vascular Endothelial Growth Factor Receptor-2 Vascular Endothelial Growth Factors Vascular blood supply Vascular remodeling clinical phenotype human morbidity human mortality in vivo limb amputation muscle necrosis muscle regeneration neovascularization novel paracrine prevent receptor response satellite cell therapeutic target

项目摘要

DESCRIPTION (provided by applicant): Peripheral artery disease (PAD) is a major cause of human morbidity and mortality. Evidence suggests that the most severe manifestation of PAD, critical limb ischemia (CLI), is clinically distinct from the more benign syndrome of intermittent claudication (IC). In mice, the propensity to develop CLI-like tissue necrosis is strain- dependent. Both susceptible (BALB/c) and resistant (C57BL/6) strains have been identified, suggesting that a similar genetic susceptibility exists in humans. Human genetic studies have demonstrated linkages to PAD, however the mechanisms that predispose to CLI vs. IC remain unknown. One reason for this may be that the vast majority of studies examining susceptibility to tissue necrosis in limb ischemia have focused on the vasculature. However, we have found that the skeletal muscle cell response, particularly that of skeletal muscle progenitor cells (MPCs), is a key determinant of tissue necrosis after limb ischemia in mice and susceptibility to CLI in humans. Moreover, our findings provide a novel mechanistic model that accounts for the role of known modulators of PAD, such as VEGF, in the development of CLI. In preliminary studies, we have developed a murine model of subacute limb ischemia that leads to muscle necrosis similar to that seen in humans with CLI, and we have demonstrated that: 1) in this model, but not in acute ischemia, mice develop large, mature neovessels in the non-ischemic limb; 2) these vessels contain cells that co-express the MPC marker Pax7 together with CD31, suggesting that MPCs can differentiate into endothelial cells (ECs); 3) ablation of Pax7+ MPCs results in dramatic tissue necrosis, even in necrosis-resistant mouse strains; 4) expression of the VEGF receptor VEGFR-2 on MPCs is induced by ischemia in necrosis-resistant but not necrosis-susceptible mice; 5) VEGF induces MPC proliferation and differentiation; and 6) loss of VEGFR-2 in MPCs in vivo results in deficient muscle regeneration. Taken together, these findings suggest a model in which MPCs, in response to VEGF stimulation, incorporate into new blood vessels to support tissue perfusion and protect muscle cells from ischemic injury. In addition, VEGF promotes MPCs' known direct contribution to muscle regeneration. Thus, we hypothesize that VEGF receptor signaling in endogenous muscle progenitor cells mediates both skeletal muscle neovascularization and myofiber regeneration after limb ischemia in order to limit muscle necrosis. To investigate this hypothesis, our Specific Aims are to: 1. Determine if MPC VEGF receptors are required for neovascularization and muscle regeneration in vivo. 2. Determine if paracrine VEGF signaling is required for MPC-mediated neovascularization in vivo. 3. Determine if MPC VEGF receptors are required for ischemic MPC proliferation, survival, and differentiation in vitro, and if MPCs are similarly affected in patients with CLI.

描述（由申请人提供）：外周动脉疾病（PAD）是人类发病率和死亡率的主要原因。有证据表明，PAD最严重的临界肢体缺血（CLI）的表现在临床上与间歇性lau不平的良性综合征（IC）不同。在小鼠中，发展CLI样组织坏死的倾向取决于应变。易感性（BALB/C）和抗性（C57BL/6）菌株均已鉴定出来，这表明人类中存在类似的遗传敏感性。人类遗传研究表明与PAD的联系是与CLI和IC易感的机制尚不清楚的。原因之一可能是，大多数研究检查了肢体缺血中对组织坏死的易感性的研究都集中在脉管系统上。但是，我们发现骨骼肌细胞反应，尤其是骨骼肌祖细胞（MPC）的骨骼肌细胞反应是小鼠肢体缺血后组织坏死的关键决定因素，并且对人类的CLI敏感性。此外，我们的发现提供了一种新型的机械模型，该模型解释了已知的PAD调节剂（例如VEGF）在CLI开发中的作用。在初步研究中，我们开发了一种亚急性肢体缺血的鼠模型，导致肌肉坏死与CLI人类相似的肌肉坏死，我们已经证明：1）在急性缺血中，但在急性缺血中，小鼠在非疾病的limb中会出现大型，成熟的新蛇卵。 2）这些容器包含与CD31一起共表达MPC标记PAX7的细胞，这表明MPC可以区分内皮细胞（ECS）； 3）PAX7+ MPC的消融也会导致剧烈的组织坏死，即使在抗坏死的小鼠菌株中。 4）VEGF受体VEGFR-2在MPCS上的表达是由耐坏死的耐坏死但不可坏死的小鼠诱导的； 5）VEGF诱导MPC增殖和分化； 6）MPC在体内的VEGFR-2损失导致肌肉再生不足。综上所述，这些发现提出了一个模型，其中MPC响应VEGF刺激，将其纳入新的血管中，以支持组织灌注并保护肌肉细胞免受缺血性损伤。此外，VEGF促进了MPC对肌肉再生的已知直接贡献。因此，我们假设内源性肌肉祖细胞中的VEGF受体信号传导介导肢体缺血后骨骼肌新生血管形成和肌纤维再生，以限制肌肉坏死。为了研究这一假设，我们的具体目的是：1。确定MPC VEGF受体在体内是否需要新血管形成和肌肉再生。 2。确定在体内MPC介导的新血管形成是否需要旁分泌VEGF信号传导。 3。确定在体外缺血性MPC增殖，存活和分化是否需要MPC VEGF受体，以及在CLI患者中是否同样影响MPC。