Ang-(1-7)及其受体调控缓激肽系统对糖尿病肾病足细胞损伤的影响及机制研究

Podocyte injury may lead to Proteinuria, which is the key cause of diabetic nephropathy(DN)’s continued progress. RAS new member Ang-(1-7) negatively regulated the traditional RAS pathway through combining with its specific Mas receptor (MasR). Bradykinin (BK) may prevent the podocyte loss in DN. Furthermore, Ang-(1-7) could increase the BK and ameliorate glycometabolism under the BK’s action. Our recent study had proved the existence of MasR in podocyte. On these grounds, we propose the hypothesis that Ang-(1-7) combining with MasR may up-regulate the BK expression, which make combined BK receptors increasing and then free BK receptors decreasing, thus antagonize the AngⅡ-ACE-AT1R axis, relieve podocyte injury and delay the DN progression. This investigation probes the effects of Ang-(1-7) and its Mas receptor regulating BK and BK receptor on podocyte injury in DN and its possible mechanisms for the first time. We will analyze the relevance of circulating Ang-(1-7), BK, urinary podocytes and protienuria through clinical cases; DN animal models will be established and podocyte will be cultured with high glucose in vitro, and then Ang-(1-7)、BK receptor agonist and antagonist will be used to interfere in order to observe the change of BK and BK receptor and podocyte injury. The study will further clarify the regulatory mechanisms and provide a new strategy for the treatment of DN and the development of the new drugs.

足细胞损伤致蛋白尿是糖尿病肾病（DN）进展的关键。RAS新成员Ang-(1-7)与其特异性的Mas受体结合而负性调控传统的RAS通路；缓激肽（BK）可防止DN足细胞丢失；而Ang-(1-7)可增加BK，并在BK的作用下改善糖代谢。我们前期研究已证实足细胞上MasR的存在；据此推测Ang-(1-7)与MasR结合，可能上调BK的表达，使BK受体结合增加，游离BK受体减少，进而拮抗Ang Ⅱ- ACE-AT1R 轴，减轻足细胞损伤，延缓DN进展。本课题首次探讨了Ang(1-7)结合MasR调控BK及BK受体对DN足细胞损伤的影响及机制；拟通过临床病例分析循环Ang-(1-7)、BK与尿足细胞、蛋白尿的相关性；建立DN动物模型及体外培养高糖刺激的足细胞，予Ang-(1-7)、BK受体激动剂、阻滞剂等干预后观察BK、BK受体变化及足细胞损伤并探讨其调控机制，为DN的诊治及新药物开发提供新的策略。

足细胞损伤在糖尿病肾病（DN）蛋白尿的发生机制中具有重要作用。肾素-血管紧张素系统(RAS) 组分Ang Ⅱ可诱导足细胞损伤和凋亡，RAS新成员Ang-(1-7) 是Ang II 的天然拮抗剂，与其特异性的Mas受体（MasR）结合可拮抗Ang II的作用而负性调控传统的RAS通路。Ang-(1-7)还可增加缓激肽(BK)表达，减轻胰岛素抵抗，改善糖代谢，可能有减轻足细胞损伤、减少蛋白尿的作用。 . 本项目通过体外培养小鼠肾小球足细胞，给予高糖刺激足细胞，模拟糖尿病肾病的体外环境，分别单独或联合给予不同浓度的Ang-(1-7)及其拮抗剂、BK受体激动剂、拮抗剂干预培养足细胞，以CCK8方法观察检测足细胞活性、高糖及不同浓度的药物对足细胞活性的影响；以流式细胞术检测足细胞凋亡；通过q-PCR、Western-blot方法检测足细胞内RAS和BK系统各指标及其相应受体的表达变化、足细胞标志物（nephrin、podocin、WT-1）的表达变化，并探讨参与其调控的信号通路。结果表明，高糖通过MAPK信号通路介导足细胞凋亡，Ang-(1-7)结合其特异性的MasR可能通过减少高糖引起的BK受体(BKB1R、BKB2R)的上调，拮抗Ang II- ACE-AT1R 轴（Ang-(1-7)/MasR与BK系统具有协同作用），抑制MAPKs信号通路激活，从而抑制足细胞凋亡，减轻足细胞损伤。. 本项目探讨了Ang-(1-7)结合其特异性的MasR调控BK及BK受体对DN足细胞损伤的影响，以及Ang-(1-7)/MasR对BK受体(BKB1R/BKB2R)的调控作用，初步探究参与其调控的信号通路，为DN发病机制、早期诊治的深入研究及临床治疗新药物的开发提供了新的策略。