Wang Xin, Xie Xin, Ni Jia-Yun, Li Jing-Yao, Sun Xi-Ang, Xie Hong-Yan, Yang Ning-Hao, Guo Heng-Jiang, Lu Li, Ning Ming, Zhou Li, Liu Jun, Xu Chen, Zhang Wei, Wen Yi, Shen Qian, Xu Hong, Lu Li-Min
Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, 200032, China.
Department of Nephrology, Children's Hospital of Fudan University, Shanghai, 201103, China.
Acta Pharmacol Sin. 2025 Jan;46(1):159-170. doi: 10.1038/s41401-024-01363-z. Epub 2024 Aug 15.
The pyroptosis of renal tubular epithelial cells leads to tubular loss and inflammation and then promotes renal fibrosis. The transcription factor Krüppel-like factor 4 (KLF4) can bidirectionally regulate the transcription of target genes. Our previous study revealed that sustained elevation of KLF4 is responsible for the transition of acute kidney injury (AKI) into chronic kidney disease (CKD) and renal fibrosis. In this study, we explored the upstream mechanisms of renal tubular epithelial cell pyroptosis from the perspective of posttranslational regulation and focused on the transcription factor KLF4. Mice were subjected to unilateral ureteral obstruction (UUO) surgery and euthanized on D7 or D14 for renal tissue harvesting. We showed that the pyroptosis of renal tubular epithelial cells mediated by both the Caspase-1/GSDMD and Caspase-3/GSDME pathways was time-dependently increased in UUO mouse kidneys. Furthermore, we found that the expression of the transcription factor KLF4 was also upregulated in a time-dependent manner in UUO mouse kidneys. Tubular epithelial cell-specific Klf4 knockout alleviated UUO-induced pyroptosis and renal fibrosis. In Ang II-treated mouse renal proximal tubular epithelial cells (MTECs), we demonstrated that KLF4 bound to the promoter regions of Caspase-3 and Caspase-1 and directly increased their transcription. In addition, we found that ubiquitin-specific protease 11 (USP11) was increased in UUO mouse kidneys. USP11 deubiquitinated KLF4. Knockout of Usp11 or pretreatment with the USP11 inhibitor mitoxantrone (3 mg/kg, i.p., twice a week for two weeks before UUO surgery) significantly alleviated the increases in KLF4 expression, pyroptosis and renal fibrosis. These results demonstrated that the increased expression of USP11 in renal tubular cells prevents the ubiquitin degradation of KLF4 and that elevated KLF4 promotes inflammation and renal fibrosis by initiating tubular cell pyroptosis.
肾小管上皮细胞的焦亡导致肾小管丢失和炎症，进而促进肾纤维化。转录因子Krüppel样因子4（KLF4）可双向调节靶基因的转录。我们之前的研究表明，KLF4的持续升高是急性肾损伤（AKI）转变为慢性肾病（CKD）和肾纤维化的原因。在本研究中，我们从翻译后调控的角度探讨了肾小管上皮细胞焦亡的上游机制，并聚焦于转录因子KLF4。对小鼠进行单侧输尿管梗阻（UUO）手术，并在第7天或第14天实施安乐死以获取肾组织。我们发现，在UUO小鼠肾脏中，由半胱天冬酶-1/ Gasdermin D（Caspase-1/GSDMD）和半胱天冬酶-3/ Gasdermin E（Caspase-3/GSDME）途径介导的肾小管上皮细胞焦亡呈时间依赖性增加。此外，我们发现转录因子KLF4的表达在UUO小鼠肾脏中也呈时间依赖性上调。肾小管上皮细胞特异性敲除Klf4可减轻UUO诱导的焦亡和肾纤维化。在血管紧张素II（Ang II）处理的小鼠肾近端小管上皮细胞（MTECs）中，我们证明KLF4与Caspase-3和Caspase-1的启动子区域结合，并直接增加它们的转录。此外，我们发现泛素特异性蛋白酶11（USP11）在UUO小鼠肾脏中增加。USP11使KLF4去泛素化。敲除Usp11或用USP11抑制剂米托蒽醌（3mg/kg，腹腔注射，在UUO手术前两周每周两次）预处理可显著减轻KLF4表达、焦亡和肾纤维化的增加。这些结果表明，肾小管细胞中USP11表达的增加可防止KLF4的泛素降解，而升高的KLF4通过引发肾小管细胞焦亡促进炎症和肾纤维化。
