Autophagy is a cell self-renewal process that relies on the degradation of the cytoplasmic proteins or organelles of lysosomes and is associated with development of numerous diseases. However, the therapeutic effect of autophagy inhibition on hyperuricemic nephropathy (HN) and the underlying mechanisms are still unknown. Here, we investigated the effect of delayed treatment with 3-methyladenine (3-MA), a specific autophagy inhibitor, on the development of HN in a rat model. Administration of 3-MA at 21 days following after uric acid injury protected kidney from hyperuricemic-related injuries, as demonstrated by improving renal dysfunction and architecture damage, blocking Beclin-1 and LC3II/I and decreasing the number of autophagic vacuoles. Late treatment with 3-MA was also effective in attenuating renal fibrosis as evidenced by reducing ECM protein deposition, blocking epithelial-to-mesenchymal transition (EMT) and decreasing the number of renal epithelial cells arrested at the G2/M phase of cell cycle. Injury to the kidney resulted in increased expression of TGFβ receptor I, and phosphorylation of Smad3, 3-MA significantly abrogated all these responses. Moreover, inhibition of autophagy suppressed mitochondrial fission, downregulated the expression of Dynamin-related protein 1 (Drp-1), Cofilin and F-actin, and alleviated cell apoptosis. Finally, 3-MA effectively blocked STAT3 and NF-κB phosphorylation and suppressed infiltration of macrophages and lymphocytes as well as release of multiple profibrogenic cytokines/chemokines in the injured kidney. Taken together, these findings indicate that hyperuricemia-induced autophagy is critically involved in the activation of renal fibroblasts, EMT, mitochondrial fission and apoptosis of tubular epithelial cells and development of renal fibrosis. Thus, this study provides evidence for autophagy inhibitors as the treatment of HN patients.

自噬是一种细胞自我更新过程，依赖于溶酶体的细胞质蛋白或细胞器的降解，并与多种疾病的发展有关。然而，自噬抑制对高尿酸血症性肾病（HN）的治疗作用及其潜在机制仍不清楚。在这里，我们研究了延迟3-甲基腺嘌呤（3-MA）（一种特定的自噬抑制剂）治疗对大鼠模型中HN发育的影响。尿酸损伤后第21天施用3-MA可保护肾脏免受高尿酸血症相关损伤的影响，这可通过改善肾功能障碍和结构损伤，阻断Beclin-1和LC3II / I并减少自噬泡的数量来证明。3-MA的后期治疗在减轻肾纤维化方面也有效，这可通过减少ECM蛋白沉积，阻断上皮向间质转化（EMT）并减少在细胞周期G2 / M期停滞的肾上皮细胞数量来证明。肾损伤导致TGFβ受体I的表达增加，并且Smad3、3-MA的磷酸化显着消除了所有这些反应。此外，自噬的抑制抑制了线粒体的分裂，下调了动力蛋白相关蛋白1（Drp-1），Cofilin和F-肌动蛋白的表达，并减轻了细胞凋亡。最后，3-MA有效地阻断了STAT3和NF-κB的磷酸化，并抑制了巨噬细胞和淋巴细胞的浸润，并在受伤的肾脏中释放了多种促纤维化细胞因子/趋化因子。在一起 这些发现表明，高尿酸血症诱导的自噬与肾脏成纤维细胞的激活，EMT，线粒体裂变和肾小管上皮细胞凋亡以及肾纤维化的发展密切相关。因此，本研究为自噬抑制剂作为HN患者的治疗提供了证据。