DJ-1调控keap1/Nrf2通路在糖尿病肾脏缺血再灌注损伤中的作用及分子机制

Oxidative stress plays an important role on diabetic renal ischemia reperfusion injury (IRI). Nrf2 is the most significant transcription factor against oxidative stress injury. Our study found that the activation of Nrf2 could attenuate renal oxidative stress injury effectively. And DJ-1, that is the new anti-oxidative gene, can inhibit keap1 to stabilize the expression of Nrf2. Our preliminary experiments showed that the expression of DJ-1 in renal tubular epithelial cells induced by high glucose was decreased significantly during hypoxia/reoxygenation treatment, which was highly correlated with renal injury. Therefore, how DJ-1 regulated keap1/Nrf2 signal pathway in diabetic renal IRI is needed to be elucidated. This research investigate the mechanism of keap1/Nrf2 signal pathway regulated by DJ-1 on diabetic renal IRI using Nrf2 activator/antagonist, DJ-1-knockout in vivo and siRNA-mediated DJ-1 knockdown ex vivo. The aim is to provide experiment basis and new thought for prevention and treatment of diabetic renal IRI.

糖尿病肾脏缺血再灌注损伤中氧化应激起着至关重要的作用。Nrf2是迄今阐明的调控细胞对抗氧化应激损伤最重要的转录因子。我们的前期研究发现促进Nrf2表达能有效减轻肾脏氧化应激损伤。新近研究显示DJ-1作为新的抗氧化应激基因，能结合抑制蛋白keap1以稳定Nrf2的表达。本研究组预实验显示，高糖条件下缺氧复氧期间肾小管上皮细胞DJ-1表达显著减少，且与其损伤高度相关。但在糖尿病肾脏缺血再灌注损伤病理机制中，DJ-1调控keap1/Nrf2信号通路的分子机制及作用亟待阐明。本研究拟通过在体动物和离体细胞实验，应用Nrf2激动/拮抗剂、DJ-1基因剔除以及DJ-1基因过表达和沉默等技术，探讨在糖尿病肾脏缺血再灌注损伤病理过程中DJ-1的改变以及对keap1/Nrf2信号通路的调控作用及分子机制，以期为有效防治糖尿病肾脏缺血再灌注损伤提供实验依据和新的思路。

围术期的糖尿病患者在应激、休克，尤其是复杂肾脏手术过程中易发生严重的肾脏缺血再灌注损伤，从而加重糖尿病肾病，导致肾功能不全。糖尿病肾脏缺血再灌注损伤发生发展过程中，氧化应激增强是关键因素， Nrf2/ARE 信号通路是目前发现最为重要的内源性抗氧化应激通路。DJ-1在体内发挥重要的抗氧化应激功能，其通过调控机体多种抗氧化基因表达，从而增强细胞的抗氧化能力。权威的糖尿病相关研究亦证实DJ-1基因的缺失可能抑制Nrf2激活剂的作用，影响Nrf2 稳定性，阻止Nrf2/ARE信号通路的激活以及下游抗氧化基因的表达，从而有效地对抗氧化应激和炎症介质造成的损伤。本课题通过大鼠糖尿病肾脏缺血再灌注模型及高糖培养NRK-52E细胞复制缺氧复氧模型，应用激动/抑制剂及基因过表达和沉默等技术，发现缺血再灌注加重糖尿病肾脏功能损伤，使糖尿病肾脏对缺血再灌注损伤耐受力降低，其主要通过DJ-1上调 Nrf2 蛋白表达，起到抗氧化应激作用，并减少细胞凋亡，对糖尿病肾缺血再灌注损伤具有保护作用，增加糖尿病肾脏对缺血再灌注损伤的耐受能力。所获研究成果进一步为临床开发糖尿病肾脏保护有效药物或措施提供潜在合适的靶点，深入探讨糖尿病肾脏缺血再灌注损伤的分子机制，对于降低糖尿病死亡率、改善患者生存质量、降低医疗成本，具有重要意义。