Paraquat (PQ) can cause multiorgan failure including acute kidney injury (AKI). Our prior study showed that Toll-interacting protein (TOLLIP) protected against PQ-induced acute lung injury. However, the role of TOLLIP in PQ-induced AKI remains undefined. This study was aimed at understanding the role and mechanism of TOLLIP in AKI. Six-eight-week-old male Wistar rats were intraperitoneally injected with 25 mg/kg PQ to induce AKI for 24 h in vivo. HK-2 cells were treated with 300 μM PQ for 24 h to induce cellular injury in vitro or 300 μM PQ and 5 μM nuclear factor-κB (NF-κB) inhibitor BAY11-7082 for 24 h. Rats were infected with adenovirus carrying TOLLIP shRNA via tail vein injection and HK-2 cells with adenovirus carrying TOLLIP shRNA or TOLLIP 48 h before PQ exposure. Results showed that TOLLIP and Toll-like receptor 2/4 (TLR2/4) expressions were boosted in the kidney after PQ intoxication. The toxic effect of PQ on the kidney and HK-2 cells was exacerbated by TOLLIP knockdown, as evidenced by aggravated glomerulus and tubule injury, inflammatory infiltration, and cell apoptosis in the kidney and increased loss of cell viability and apoptotic cells in HK-2 cells. TOLLIP knockdown also enhanced PQ-induced NLR family pyrin domain-containing 3 (NLRP3) inflammasome activation in vivo and in vitro and TLR2/4-NF-κB signaling in vitro, reflected by increased contents of proinflammatory cytokines and expressions of NLRP3 inflammasome-related proteins in the kidney and HK-2 cells and expressions of TLR2, TLR4, and nuclear NF-κB p65 in HK-2 cells. However, TOLLIP overexpression inhibited PQ-induced loss of cell viability, cell apoptosis, NLRP3 inflammasome activation, and TLR2/4-NF-κB signaling in vitro. Additionally, BAY11-7082 abolished TOLLIP knockdown-induced NLRP3 inflammasome activation in vitro, indicating that TOLLIP protected against NLRP3 inflammasome activation in PQ-induced AKI through inhibiting TLR2/4-NF-κB signaling. This study highlights the importance of TOLLIP in AKI after PQ intoxication.

中文翻译：

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TOLLIP 的过表达通过抑制由 Toll 样受体 2/4 信号传导调节的 NLRP3 炎性体激活来防止百草枯中毒后的急性肾损伤

百草枯 (PQ) 可导致多器官衰竭，包括急性肾损伤 (AKI)。我们之前的研究表明，Toll 相互作用蛋白 (TOLLIP) 可以防止百草枯引起的急性肺损伤。然而，TOLLIP 在百草枯诱导的 AKI 中的作用仍未确定。本研究旨在了解 TOLLIP 在 AKI 中的作用和机制。对六八周大的雄性 Wistar 大鼠腹腔注射 25 mg/kg PQ 以在体内诱导 AKI 24 h 。HK-2 细胞用 300  μM PQ 处理 24 小时以在体外诱导细胞损伤或 300  μM PQ 和 5  μM核因子-κ B (NF- κB) 抑制剂 BAY11-7082 24 小时。在 PQ 暴露前 48 小时，通过尾静脉注射用携带 TOLLIP shRNA 的腺病毒感染大鼠，用携带 TOLLIP shRNA 或 TOLLIP 的腺病毒感染 HK-2 细胞。结果表明，百草枯中毒后肾脏中的 TOLLIP 和 Toll 样受体 2/4 (TLR2/4) 表达增强。PQ 对肾脏和 HK-2 细胞的毒性作用因 TOLLIP 敲低而加剧，表现为肾小球和肾小管损伤加重、炎症浸润和细胞凋亡，以及 HK-2 中细胞活力和凋亡细胞的丧失增加细胞。TOLLIP 敲低还增强了 PQ 诱导的 NLR 家族 pyrin 结构域 3 (NLRP3)在体内和体外的炎症小体活化和 TLR2/4-NF-κB信号传导在体外，表现为肾和 HK-2 细胞中促炎细胞因子和 NLRP3 炎症小体相关蛋白的表达增加，以及 HK-2 细胞中 TLR2、TLR4 和核 NF-κB p65的表达增加。然而，TOLLIP 过表达在体外抑制 PQ 诱导的细胞活力丧失、细胞凋亡、NLRP3 炎性体激活和 TLR2/4-NF-κB信号传导。此外，BAY11-7082在体外消除了 TOLLIP 敲低诱导的 NLRP3 炎性体激活，表明 TOLLIP 通过抑制 TLR2/4-NF-κB 信号传导在 PQ 诱导的 AKI 中防止 NLRP3 炎性体激活。本研究强调了 TOLLIP 在百草枯中毒后 AKI 中的重要性。