C-KIT SIGNALING IN COLLATERALS REMODELING

标题：侧支重构中的C-KIT信号转导 严重肢体缺血(CLI)是外周动脉疾病的最高级形式。此刻, 血管内手术和搭桥手术是治疗四肢的唯一有效方法。 血运重建。然而，相当大比例的CLI患者不是这些患者的理想候选者。 干预，需要一次截肢作为主要治疗选择。因此，一个有效的 预防CLI及其破坏性后果的药物策略代表了一种更多的- 为这一患者群体提供必要的替代方案。动脉形成是一种生理代偿过程 在这种情况下，预先存在的侧支扩张并作为动脉严重闭塞的自然旁路。 我们最近发现c-Kit受体酪氨酸激酶在血管重构中起关键作用。 动脉形成过程中的侧支。我们发现c-Kit功能缺陷会影响血流 肢体缺血后恢复，但未通过c-Kit的造血重建解决 活动。我们已经证实，与对照组相比，c-Kit突变小鼠的动脉生成存在缺陷。 从机制上，我们加深了对c-Kit/Kruppel-like factor4(KLF4)通路的理解 策划连带重塑。因此，我们的中心假设是c-Kit/KLF-4信号 控制平滑肌细胞(SMC)成熟阶段收缩表型的恢复 动脉生成，防止侧支过度重塑和狭窄。我们提出了两个具体的 AIMS(SA)检验我们的假设。在SA1中，我们将演示血管c-Kit的参与 动脉形成中的信号转导。我们将专门研究c-Kit的失活或激活 SMC将导致功能障碍或最佳的动脉生成，在独特的转基因模型的损失和获得- C-Kit的功能。我们还将确定可以通过 SMC c-Kit上的功能损失或增加。在SA2中，我们将剖析上游的分子通路和 在SMC中c-Kit的下游。首先，我们将研究循环应变是否决定了振荡 通过激活蛋白激酶C表达c-Kit受体，导致c-Kit抑制。接下来，我们 将确定c-Kit是否通过FBXO32介导的泛素化抑制KLF4，从而恢复 收缩的SMC表型和预防缺陷重塑。 相关性：美国约有8万例大腿截肢 每年由于CLI。在这项研究中，我们将寻找新的治疗靶点来改善动脉生成。 并防止或减轻CLI的破坏性影响。此外，我们还将鉴定分子 SMC中决定表型转换的机制，这可能适用于理解 以及其他血管闭塞性疾病的治疗。

TITLE: C-KIT SIGNALING IN COLLATERALS REMODELING Critical limb ischemia (CLI) is the most advanced form of peripheral arterial disease. At the moment, endovascular procedures and bypass surgeries are the only effective treatments for limb revascularization. However, a significant proportion of CLI patients are not good candidates for these interventions, requiring primary amputation as the main treatment option. Therefore, an effective pharmacological strategy that prevents CLI and its devastating consequences represents a much- needed alternative for this patient population. Arteriogenesis is a physiological compensatory process in which pre-existing collaterals enlarge and serve as natural bypasses to severe occlusion of arteries. We have recently identified that the c-Kit receptor tyrosine kinase plays a key role in the remodeling of collaterals during arteriogenesis. We found that defective c-Kit function compromises blood flow recovery after hindlimb ischemia, which was not resolved with hematopoietic reconstitution of c-Kit activity. We have confirmed defective arteriogenesis in c-Kit mutant mice compared to controls. Mechanistically, we advanced our understanding of how the c-Kit/Kruppel-like factor 4 (KLF4) pathway orchestrates collateral remodeling. Therefore, our central hypothesis is that c-Kit/KLF-4 signaling controls the recovery of the smooth muscle cell (SMC) contractile phenotype at the maturation phase of arteriogenesis to prevent excessive remodeling and narrowing of collaterals. We propose two Specific Aims (SA) to test our hypothesis. In SA1, we will demonstrate the involvement of vascular c-Kit signaling in arteriogenesis. We will investigate whether inactivation or activation of c-Kit specifically in SMCs will lead to dysfunction or optimal arteriogenesis in unique transgenic models of loss- and gain- of-function of c-Kit, respectively. We will also identify molecular mechanisms that can be altered by the loss- or gain-of-function on SMC c-Kit. In SA2, we will dissect the molecular pathways upstream and downstream of c-Kit in SMCs. First, we will investigate whether cyclic strain dictates the oscillatory expression of the c-Kit receptor by activating protein kinase C, leading to c-Kit suppression. Next, we will determine whether c-Kit inhibits KLF4 through FBXO32-mediated ubiquitination, thereby restoring the contractile SMC phenotype and preventing defective remodeling. RELEVANCE: Approximately 80,000 major lower-extremity amputations occur in the United States every year due to CLI. In this study, we will identify novel therapeutic targets to improve arteriogenesis and prevent or alleviate the devastating effects of CLI. Moreover, we will identify the molecular mechanism that dictates phenotypic switching in SMCs, which may be applicable to the understanding and treatment of other vascular occlusive diseases.