apelin/APJ通过内皮细胞ET-1和BKCa促进糖尿病微血管并发症的作用及机制研究

apelin及其受体APJ是除高血糖外参与糖尿病微血管损伤的重要因素。我们已证实，2型糖尿病时内皮细胞APJ表达降低，血液中增加的apelin却可通过增加eNOS影响内皮细胞依赖的血管及肾功能。因此推测，apelin和APJ可能通过各自独立的信号通路影响内皮细胞功能，从而导致血管和肾功能损伤。本研究利用1型和2型糖尿病模型，探讨apelin/APJ导致内皮细胞功能异常，进而影响血管和肾功能的机制；通过内皮细胞APJ基因敲除小鼠，探讨apelin通过APJ非依赖信号影响内皮细胞功能的机制；通过内皮细胞BKCa基因敲入小鼠，探讨BKCa介导的内皮细胞超极化异常是apelin/APJ影响内皮功能的共同通路；通过培养内皮细胞，探讨APJ感受apelin和牵张刺激调控β-arrestin/BKCa（ET-1）信号的机制。最终论证糖尿病时 apelin/APJ导致内皮依赖性血管和肾功能损伤的分子机制。

Besides hyperglycemia, apelin, an adipokine, and its receptor APJ are important potential factors that may be involved in the diabetic microvascular injuries in diabetes. Our works have revealed that apelin which was increased in the blood in type 2 diabetes would affect the vascular and renal functions by increasing eNOS in endothelial cells in spite of the decreased expression of APJ in endothelial cells, which would induce the increasing of renal blood flow and resulted in the diabetic kidney diseases. Therefore it is supposed that apelin and APJ might induce endothelial dysfunction in diabetes via independent pathways, which would lead to the vascular and renal dysfunction in diabetes. In this study, type 1 and type 2 diabetes which displayed different changes of expression for apelin and APJ were adopted to investigate the mechanisms for apelin/APJ in inducing vascular and renal injuries via causing endothelial dysfunction in diabetes; specific endothelial APJ gene knockout mice were adopted to investigate the APJ -dependent and -independent pathways for apelin in inducing endothelial dysfunction; specific endothelial BKCa gene knockin mice were adopted to investigate that dysfunction of endothelial hyperpolarization induced by BKCa was the shared pathway for apelin and APJ in inducing endothelial dysfunction; cultured endothelial cells were adopted to investigate the intracellular signaling pathways(β-arrestin/ BKCa（ET-1）)for APJ in endothelial cells activated by apelin and stretch. The final aim of this study is to demonstrate the molecular pathways for changed expression of apelin and APJ in inducing endothelial dysfunction and resulted in diabetic vascular and renal dysfunction in diabetes.