NQO1 通过抑制糖尿病肾病中的 TLR4/NF-κB 和 TGF-β/Smad 信号通路来减轻肾纤维化。
NQO1 alleviates renal fibrosis by inhibiting the TLR4/NF-κB and TGF-β/Smad signaling pathways in diabetic nephropathy.
机构信息
Department of Pathology, Hebei Medical University, Shijiazhuang, China; Department of Pathology, The First Hospital of Hebei Medical University, Shijiazhuang, China.
Department of Pathology, Hebei Medical University, Shijiazhuang, China.
出版信息
Cell Signal. 2023 Aug;108:110712. doi: 10.1016/j.cellsig.2023.110712. Epub 2023 May 15.
OBJECTIVE
Diabetic nephropathy (DN) is one of the main complications of diabetes, and inflammation and fibrosis play an important role in its progression. NAD(P)H: quinone oxidoreductase 1 (NQO1) protects cells from oxidative stress and damage caused by toxic quinones. In the present study, we aimed to investigate the protective effects of NQO1 against diabetes-induced renal inflammation and fibrosis and the underlying mechanisms.
METHODS
In vivo, the kidneys of type 2 diabetes model db/db mice were infected with adeno-associated virus vectors to induce NQO1 overexpression. In vitro, human renal tubular epithelial (HK-2) cells transfected with NQO1 pcDNA3.1(+) were cultured under high-glucose (HG) conditions. Gene and protein expression was assessed by quantitative real-time PCR, Western blotting, immunofluorescence, and immunohistochemical staining. Mitochondrial reactive oxygen species (ROS) were detected with MitoSOX Red.
RESULT
Our study revealed that the expression of NQO1 was markedly downregulated and that Toll-like receptor (TLR)4 and TGF-β1 expression was upregulated in vivo and in vitro under diabetic conditions. Overexpression of NQO1 suppressed proinflammatory cytokine (IL-6, TNF-α, MCP-1) secretion, extracellular matrix (ECM) (collagen IV, fibronectin) accumulation and epithelial-mesenchymal transition (EMT) (α-SMA, E-cadherin) in the db/db mouse kidneys and HG-cultured HK-2 cells. Furthermore, NQO1 overexpression ameliorated HG-induced TLR4/NF-κB and TGF-β/Smad pathways activation. Mechanistic studies demonstrated that a TLR4 inhibitor (TAK-242) suppressed the TLR4/NF-κB signaling pathway, proinflammatory cytokine secretion, EMT and ECM-related protein expression in HG-exposed HK-2 cells. In addition, we found that the antioxidants N-acetylcysteine (NAC) and tempol increased the expression of NQO1 and decreased the expression of TLR4, TGF-β1, Nox1, and Nox4 and ROS production in HK-2 cells cultured under HG conditions.
CONCLUSIONS
These data suggest that NQO1 alleviates diabetes-induced renal inflammation and fibrosis by regulating the TLR4/NF-κB and TGF-β/Smad signaling pathways.
目的
糖尿病肾病（DN）是糖尿病的主要并发症之一，炎症和纤维化在其进展中起着重要作用。烟酰胺腺嘌呤二核苷酸（磷酸）：醌氧化还原酶 1（NQO1）可保护细胞免受氧化应激和毒性醌引起的损伤。本研究旨在探讨 NQO1 对糖尿病诱导的肾炎症和纤维化的保护作用及其潜在机制。
方法
在体内，2 型糖尿病模型 db/db 小鼠的肾脏感染腺相关病毒载体以诱导 NQO1 过表达。在体外，用 NQO1 pcDNA3.1(+)转染人肾小管上皮（HK-2）细胞在高糖（HG）条件下培养。通过实时定量 PCR、Western blot、免疫荧光和免疫组织化学染色评估基因和蛋白表达。用 MitoSOX Red 检测线粒体活性氧（ROS）。
结果
本研究表明，在糖尿病条件下，体内和体外 NQO1 的表达明显下调，Toll 样受体（TLR）4 和 TGF-β1 的表达上调。NQO1 的过表达抑制了促炎细胞因子（IL-6、TNF-α、MCP-1）的分泌、细胞外基质（ECM）（胶原 IV、纤连蛋白）的积累和 db/db 小鼠肾脏和 HG 培养的 HK-2 细胞中的上皮-间充质转化（EMT）（α-SMA、E-钙粘蛋白）。此外，NQO1 的过表达改善了 HG 诱导的 TLR4/NF-κB 和 TGF-β/Smad 途径的激活。机制研究表明，TLR4 抑制剂（TAK-242）抑制了 TLR4/NF-κB 信号通路，HG 暴露的 HK-2 细胞中促炎细胞因子的分泌、EMT 和 ECM 相关蛋白的表达。此外，我们发现抗氧化剂 N-乙酰半胱氨酸（NAC）和替普在 HG 条件下培养的 HK-2 细胞中增加 NQO1 的表达，降低 TLR4、TGF-β1、Nox1、Nox4 的表达和 ROS 的产生。
结论
这些数据表明，NQO1 通过调节 TLR4/NF-κB 和 TGF-β/Smad 信号通路缓解糖尿病引起的肾炎症和纤维化。
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