PKC Isoenzymes and Diabetic Microvascular Hyperpermeability

微血管高通透性是一种重要的损伤过程 许多炎症性疾病，包括糖尿病并发症。我们研究计划的长期目标是 了解微血管屏障功能调节的细胞和分子机制 在生理和病理条件下。作为该计划的一个组成部分，该项目是 旨在阐明与微血管有关的信号通路和分子机制 糖尿病发展过程中的高渗透性，这是一种影响大量高密度人群的疾病 以微血管损伤为特征的并发症导致的发病率和死亡率。我们的中央 假说认为糖尿病通过多种途径上调微血管内皮细胞PKCβ MAPK刺激的基因表达，PDK1增强的催化活性，以及DAG介导的激酶激活。 我们进一步认为，上调的PKCβ增加了小静脉内皮细胞旁的通透性 通过GDI-RhoA-ROCK级联结合细胞间连接诱导内皮细胞收缩 β-连环蛋白磷酸化和VE-钙粘蛋白解离引发的解离。三个具体目标 建议：1)明确地确定PKCβ在糖尿病微血管渗漏中的作用；2) 研究糖尿病猪PKCβ上调的信号机制；3)阐明PKCβ上调的信号转导机制 PKCβ诱导的微血管高通透性的分子基础。这些目标将会实现 通过将分子技术与功能相结合的多方面分子生理学方法 在微血管水平上进行分析。一个与人类相关的糖尿病猪模型将作为主要模型 用于定量评估完整微血管的内皮屏障功能。来自这项研究的数据 将为糖尿病微血管并发症的发病机制提供新的见解。身份识别 PKC诱导的终末点损伤的精确分子机制可能导致一条新的途径 寻找治疗靶点。在此研究的基础上，对今后的研究方向进行了展望 发展微血管渗漏的分子探针和治疗方法 与慢性炎症性疾病有关。

Microvascular hyperpermeability represents an important injurious process underlying the development of many inflammatory diseases including diabetic complications. The long-term goal of our research program is to understand the cellular and molecular mechanisms in the regulation of microvascular barrier function under physiological and pathological conditions. As an integral component of the program, this project is designed to elucidate the signaling pathways and molecular mechanisms responsible for microvascular hyperpermeability during development of diabetes, a disease that affects a large population with high morbidity and mortality resulting from complications characterized by microvascular injury. Our central hypothesis states that diabetes upregulates PKCbeta in microvascular endothelium at multiple levels via MAPK-stimulated gene expression, PDK1-potentiated catalytic activity, and DAG-mediated kinase activation. We further propose that upregulated PKCbeta increases the paracellular permeability of venular endothelium by inducing endothelial cell contraction via the GDI-RhoA-ROCK cascade coupled with intercellular junction disorganization triggered by beta-catenin phosphorylation and VE-cadherin dissociation. Three specific aims are proposed: 1) to unequivocally establish the role of PKCbeta in microvascular leakage during diabetes; 2) to characterize the signaling mechanisms of PKCbeta upregulation in diabetic pigs; and 3) to elucidate the molecular basis of PKCbeta-elicited microvascular hyperpermeability. These aims will be accomplished through a multifaceted molecular physiology approach that incorporates molecular techniques with functional analyses at the microvascular level. A human-relevant pig model of diabetes will serve as the primary model for quantitative assessment of endothelial barrier function in intact microvessels. Data derived from this study will provide new insights into the pathogenesis of diabetic microvascular complications. Identification of the precise molecular mechanisms responsible for PKC-induced end-point injury may lead to a new avenue for searching therapeutic targets. Based on this study, a future direction of our research efforts will be directed to the development of molecular probes and therapies for diagnosis and treatment of microvascular leakage associated with chronic inflammatory diseases.