Department of Emergency, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China.
Department of Nephrology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China.
Ren Fail. 2024 Dec;46(2):2361089. doi: 10.1080/0886022X.2024.2361089. Epub 2024 Jun 14.
As a pattern recognition receptor, Toll-like receptor 4 (TLR4) is crucial for the development and progression of acute kidney injury (AKI). This study aims to explore whether the deubiquitinase Usp9x influences the TLR4/NF-B pathway to cause sepsis-induced acute kidney injury (S-AKI). The model of AKI was established in Sprague-Dawley rats using the cecal ligation and puncture (CLP) method, while renal tubular epithelial cell NRK-52E was stimulated with lipopolysaccharide (LPS) . All plasmids were transfected into NRK-52E cells according to the indicated group. The deubiquitinase of TLR4 was predicted by the online prediction software Ubibrowser. Subsequently, Western blot and Pearson correlation analysis identified Usp9x protein as a potential candidate. Co-IP analysis verified the interaction between TLR4 and Usp9x. Further research revealed that overexpression of Usp9x inhibited degradation of TLR4 protein by downregulating its ubiquitination modification levels. Both and experiments observed that interference with Usp9x effectively alleviated the inflammatory response and apoptosis of renal tubular epithelial cells (RTECs) induced by CLP or LPS, whereas overexpression of TLR4 reversed this situation. Transfection with sh-Usp9x in NRK-52E cells suppressed the expression of proteins associated with the TLR4/NF-κB pathway induced by LPS. Moreover, the overexpression of TLR4 reversed the effect of sh-Usp9x transfection. Therefore, the deubiquitinase Usp9x interacts with TLR4, leading to the upregulation of its expression through deubiquitination modification, and the activation of the TLR4/NF-κB signaling pathway, thereby promoting inflammation and apoptosis in renal tubular epithelial cells and contributing to sepsis-induced acute kidney injury.
作为模式识别受体,Toll 样受体 4(TLR4)对于急性肾损伤(AKI)的发展和进展至关重要。本研究旨在探讨去泛素化酶 Usp9x 是否通过影响 TLR4/NF-B 途径导致脓毒症诱导的急性肾损伤(S-AKI)。采用盲肠结扎穿孔(CLP)法建立 AKI 模型,用脂多糖(LPS)刺激肾小管上皮细胞 NRK-52E。根据指示的组,将所有质粒转染到 NRK-52E 细胞中。通过在线预测软件 Ubibrowser 预测 TLR4 的去泛素化酶。随后,Western blot 和 Pearson 相关性分析确定 Usp9x 蛋白为潜在候选物。Co-IP 分析验证了 TLR4 和 Usp9x 之间的相互作用。进一步的研究表明,Usp9x 的过表达通过下调其泛素化修饰水平抑制 TLR4 蛋白的降解。和 实验均观察到,干扰 Usp9x 可有效减轻 CLP 或 LPS 诱导的肾小管上皮细胞(RTEC)的炎症反应和凋亡,而过表达 TLR4 则逆转了这种情况。在 NRK-52E 细胞中转染 sh-Usp9x 可抑制 LPS 诱导的 TLR4/NF-κB 通路相关蛋白的表达。此外,TLR4 的过表达逆转了 sh-Usp9x 转染的作用。因此,去泛素化酶 Usp9x 与 TLR4 相互作用,通过去泛素化修饰上调其表达,并激活 TLR4/NF-κB 信号通路,从而促进肾小管上皮细胞的炎症和凋亡,导致脓毒症诱导的急性肾损伤。
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