HIF通路去苏素化修饰对AKI-to-CKD进展中肾小球损伤的保护作用及机制

Acute kidney injury (AKI) is an independent risk factor for chronic kidney disease (CKD). Some AKI patients may eventually evolve into CKD or end-stage renal disease. However, the mechanism of the progressive renal changes following AKI remains unclear. Recent studies have found that glomerular endothelial cell damage and dysfunction plays an important role in the development of AKI-to-CKD. Our previous research indicated that SENP1 was essential for activating HIF-1α pathway and VEGF secretion in cultured podocytes, which subsequently protected co-cultured glomerular endothelial cells from hypoxic induced injury and apoptosis. In this study, we plan to establish a rat model imitating the pathological changes of glomeruli during AKI-to-CKD in vivo. Using the SENP1 short hairpin RNA (shRNA) recombinant adenovirus vector and SENP1 DNA recombinant adenovirus vector, we will create SENP1-knockdown and SENP1 overexpression AKI-to-CKD rat models. We hope to verify that SENP1 mediated HIF deSUMOylation is an important point regulating the immunological changes, inflammatory reactions, oxidative stress, and glomerular sclerosis induced by acute kidney injury. Our findings should provide a new strategy for the treatment of the glomerular changes and dysfunction during the process of AKI-to-CKD.

急性肾损伤（AKI）是慢性肾脏病（CKD）的独立危险因素，部分患者可最终演变为CKD或终末期肾脏病，然而其机制不清。近年研究发现肾小球毛细血管内皮细胞损伤和功能障碍在AKI-to-CKD的发生发展中发挥重要作用。我们前期的体外研究已证实，SENP1介导的HIF通路去苏素化修饰可以调节足细胞中VEGF的生成，并通过旁分泌作用保护肾小球内皮细胞抵御缺氧诱导的损伤和凋亡，促进内皮细胞的迁移并形成毛细血管网。本研究在此基础上，进一步构建大鼠AKI-to-CKD肾小球损伤模型，利用SENP1腺病毒高表达和低表达载体在体内干预SENP1的表达，探索SENP1介导的去苏素化修饰是否能够在体内调控HIF通路的活化进而阻断AKI-to-CKD进展，为阻抑AKI后肾小球病变的进展提供新的治疗策略。

急性肾损伤是临床常见的危重急症之一，在住院患者的发病率约为5%， ICU 中发病率约为35%，死亡率高达50-80%，是院内患者死亡的常见病因。既往研究认为，AKI是一种急性可逆性损伤，受损伤的肾组织结构能够逐渐恢复正常。但近年的研究发现 AKI 是慢性肾脏病（CKD）的独立危险因素，部分患者可最终演变为 CKD 或终末期肾脏病，然而其机制不清。近年研究发现肾小球毛细血管内皮细胞、足细胞损伤和功能障碍在AKI-to-CKD的发生发展中发挥重要作用，肾小球损伤和功能障碍使肾组织处于缺血缺氧状态，进一步损伤肾小管，共同参与肾间质纤维化进程。我们在既往研究中证实，SENP1介导的HIF通路去苏素化修饰可以调节足细胞中VEGF的生成，并通过旁分泌作用保护肾小球内皮细胞抵御缺氧诱导的损伤和凋亡，促进内皮细胞的迁移并形成毛细血管网。本研究在此基础上，进一步构建大鼠、小鼠AKI-to-CKD肾小球损伤模型，利用SENP1腺病毒高表达和低表达载体在体内干预SENP1的表达，采用 Westernblot、 Real-time PCR、免疫组化等分子生物学方法，取得研究成果如下：证实抑制SENP1表达，HIF/VEGF通路失活，肾脏AKI后肾小球硬化和间质纤维化程度明显加重，而上调SENP1能够活化HIF/VEGF通路，促进VEGF分泌，减轻肾脏缺血再灌注的氧化应激损伤及ECM积聚，改善AKI后肾小球损伤，从而阻断AKI-to-CKD进展。本研究首次揭示了SENP1调控的HIF/VEGF通路去苏素化修饰对肾脏缺血再灌注损伤具有保护作用，并且抑制AKI-to-CKD进展这一重要分子机制，提示SENP1/HIF/VEGF通路可以作为阻抑AKI后肾小球病变进展的潜在治疗靶点，为预防和治疗AKI-to-CKD进展提供了崭新的思路与临床应用前景。