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

• 批准号: 8887762
• 负责人: Christopher D Kontos
• 金额: $ 42.98万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8887762
• 关键词: Ablation; Accounting; Acute; Affect; Benign; Blood Vessels; Cell Count; Cell Differentiation process; Cell Proliferation; Cell fusion; Cell physiology; Cells; Cessation of life; Clinical; Development; Differentiation Antigens; Disease; Endothelial Cells; Event; Genes; Genetic Predisposition to Disease; Genetic study; Goals; Growth; 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; public health relevance; receptor; response; satellite cell; therapeutic target

 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）是人类发病和死亡的主要原因。有证据表明，PAD 最严重的表现是严重肢体缺血 (CLI)，在临床上与间歇性跛行 (IC) 等良性综合征不同。在小鼠中，发生 CLI 样组织坏死的倾向与菌株有关。已鉴定出易感菌株（BALB/c）和耐药菌株（C57BL/6），这表明人类中存在类似的遗传易感性。人类遗传学研究已证明与 PAD 存在联系，但导致 CLI 与 IC 的机制仍不清楚。原因之一可能是绝大多数检查肢体缺血组织坏死易感性的研究都集中在脉管系统上。然而，我们发现骨骼肌细胞反应，特别是骨骼肌祖细胞（MPC）的反应，是小鼠肢体缺血后组织坏死和人类对 CLI 易感性的关键决定因素。此外，我们的研究结果提供了一种新颖的机制模型，该模型解释了已知的 PAD 调节剂（例如 VEGF）在 CLI 发展中的作用。在初步研究中，我们开发了一种亚急性肢体缺血的小鼠模型，该模型会导致类似于人类 CLI 中所见的肌肉坏死，并且我们已经证明：1）在该模型中，但在急性缺血中，小鼠在非缺血肢体中发育出大而成熟的新血管； 2) 这些血管含有与 CD31 一起表达 MPC 标记 Pax7 的细胞，表明 MPC 可以分化为内皮细胞 (EC)； 3) Pax7+ MPCs 的消融会导致严重的组织坏死，甚至在抗坏死小鼠品系中也是如此； 4)MPCs上VEGF受体VEGFR-2的表达是由缺血诱导的，在坏死抵抗性小鼠中，但在坏死易感性小鼠中则不然； 5）VEGF诱导MPC增殖和分化； 6) 体内 MPC 中 VEGFR-2 的缺失导致肌肉再生不足。总而言之，这些发现提出了一种模型，其中 MPC 响应 VEGF 刺激，融入新血管以支持组织灌注并保护肌肉细胞免受缺血性损伤。此外，VEGF 还可促进 MPC 对肌肉再生的直接贡献。因此，我们假设内源性肌肉祖细胞中的 VEGF 受体信号传导在肢体缺血后介导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，我们的具体目标是： 1. 确定体内新生血管形成和肌肉再生是否需要 MPC VEGF 受体。 2. 确定旁分泌 VEGF 信号传导是否是 MPC 介导的体内新血管形成所必需的。 3. 确定体外缺血性 MPC 增殖、存活和分化是否需要 MPC VEGF 受体，以及 CLI 患者中的 MPC 是否受到类似影响。