Oct4 and Klf4 regulate microvascular SMC-pericyte plasticity, angiogenesis, and metabolic dysfunction

微血管炎症和功能障碍被广泛认为是许多临床上 糖尿病和代谢性疾病的并发症，包括肾功能衰竭和心力衰竭、神经病变和斑疹 退化。关于白细胞和内皮细胞(EC)的作用机制已知很多 这一过程。然而，尽管有令人信服的证据表明血管周围的异常投资是顺利的 肌细胞和周细胞(SMC-Pc)是微血管疾病发病机制的共同特征，目前知之甚少 关于这些细胞可能对这一进程作出贡献的作用或机制。SMC-PC不足 新生EC管的包埋也是试图诱导治疗性血管生成的主要限制因素 以促进伤口修复或从缺血损伤中恢复。事实上，这包括许多失败的血管内皮生长因子临床试验 有强健的EC管形成，但未能形成成熟的功能性血管网络 血液输送，因为血管缺乏SMC-Pc覆盖，并且扩张和泄漏。这项提案中的研究将 检验干细胞多能性基因Oct4和Klf4在 微血管SMC-Pc在损伤后血管重塑过程中的可塑性调节 缺氧，以及与之相关的微血管炎症和功能障碍的发展 代谢性疾病。与这一假设一致，我们实验室的初步研究使用独特的SMC-Pc特异性 EYFP谱系追踪小鼠+/-同时条件基因敲除(KO)在SMC-Pc中显示 SMC-Pc中Oct4的表达是角膜烧伤和后肢功能性血管生成所必需的 缺血模型。此外，我们在这个修订的应用程序中提供了令人兴奋的新数据，表明KLF4 SMC-Pc在微血管中的表达在调节先天代谢和炎症中起关键作用 即使在非高脂血症时肠系膜微血管网络及其周围脂肪组织的特性 老鼠。目标1将验证这样的假设，即在微血管SMC-Pc中激活Oct4是关键的心率限制 正常和功能失调的血管生成，包括与饮食诱导的肥胖相关的血管生成 (Dio)/代谢性疾病。Aim 2将确定在微血管内调节Oct4重新激活的机制 SMC-Pc包括检验低氧、核因子κB和KLF4依赖的假设。目标3将测试 KLF4依赖的微血管SMC-Pc表型转变在血管病变中起关键保护作用的假说 调节正常脂肪组织的固有代谢和炎症特性以及这些特性的丧失 保护作用在新陈代谢发育过程中导致全球微血管炎症/功能障碍 疾病。研究可能导致新的治疗方法，以增强治疗性血管生成和/或治疗和 预防微血管疾病、糖尿病并发症和代谢性疾病。

Microvascular inflammation and dysfunction is widely believed to be the underlying cause of many of the clinical complications of diabetes and metabolic disease including renal and heart failure, neuropathy, and maculae degeneration. Much is known regarding mechanisms by which leucocytes and endothelial cells (EC) contribute to this process. However, in spite of compelling evidence that abnormal investment of perivascular smooth muscle cells and pericytes (SMC-Pc) is a common feature of microvascular disease pathogenesis, little is known regarding the role or mechanisms by which these cells might contribute to this process. Inadequate SMC-Pc investment of nascent EC tubes is also a major rate-limiting factor in attempts to induce therapeutic angiogenesis to augment wound repair or recovery from ischemic injury. Indeed, this includes many failed VEGF clinical trials where there is robust formation of EC tubes but failure to form a mature functional vascular network with efficient blood delivery because vessels lack SMC-Pc coverage and are dilated and leaky. Studies in this proposal will test the overall hypothesis that the stem cell pluripotency genes Oct4 and Klf4 play a critical role in regulating the plasticity of microvascular SMC-Pc during vascular remodeling in response to injury and hypoxia, as well as development of microvascular inflammation and dysfunction associated with metabolic disease. Consistent with this hypothesis, initial studies by our lab using unique SMC-Pc specific eYFP lineage tracing mice +/- simultaneous conditional knockout (KO) of Oct4 exclusively in SMC-Pc showed that Oct4 expression within SMC-Pc is required for functional angiogenesis in corneal burn and hind limb ischemia models. Moreover, we present exciting new data in this revised application showing that Klf4 expression within microvascular SMC-Pc plays a critical role in regulating the innate metabolic and inflammatory properties of the mesenteric microvascular network and surrounding adipose tissue even in non-hyperlipidemic mice. Aim 1 will test the hypothesis that activation of Oct4 within microvascular SMC-Pc is a key rate-limiting step in both normal and dysfunctional angiogenesis including that associated with diet-induced obesity (DIO)/metabolic disease. Aim 2 will determine mechanisms that regulate Oct4 re-activation within microvascular SMC-Pc including testing the hypothesis that it is hypoxia, NFκB, and Klf4-dependent. Aim 3 will test the hypothesis that Klf4-dependent phenotypic transitions of microvascular SMC-Pc play a key protective role in regulating the innate metabolic and inflammatory properties of normal adipose tissue and that loss of these protective effects contribute to global microvascular inflammation/dysfunction during development of metabolic disease. Studies may lead to novel therapeutic approaches for enhancing therapeutic angiogenesis and/or treating and preventing microvascular disease complications of diabetes and metabolic disease.