Abudoureyimu Abudoushalamu, Chen Chen, Hu Yan, Nuermaimaiti Dilihumaer, Liu Tao
Department of Geriatrics, Xinjiang Medical University Affiliated Traditional Chinese Medicine Hospital, Urumqi City, Xinjiang Uygur Autonomous Region, China.
Xinjiang Medical University, Urumqi City, Xinjiang Uygur Autonomous Region, China.
Cell Immunol. 2025 Aug;414:104997. doi: 10.1016/j.cellimm.2025.104997. Epub 2025 Jun 17.
The activation imbalance of M1/M2 macrophage phenotypes is crucial in diabetic nephropathy (DN). This study aimed to explore the molecular mechanisms underlying quercetin's action against DN.
In vitro, RAW 264.7 macrophages were incubated with high glucose (HG) with or without quercetin. Overexpression of NLRC5 was investigated to elucidate the mechanism. M1/M2 macrophage differentiation was assessed by flow cytometry using cell surface markers CD86 and CD206. In vivo, a DN mouse model was created using a high-fat diet and streptozotocin (STZ). Quercetin was administered intragastrically to DN mice at 50 mg/kg and 100 mg/kg. After euthanasia, mouse kidneys were analyzed by hematoxylin and eosin (H&E), Masson's trichrome, and immunohistochemistry (IHC) staining. ELISA assay and western blot analysis were performed to determine related molecular levels.
In vitro, quercetin significantly reduced HG-induced expressions of CD86, iNOS, NLRC5, NLRP3, and pro-inflammatory cytokines (TNF-α, IL-6, IL-1β), while increasing HG-induced CD206, Arg-1, and IL-10 in RAW 264.7 macrophages. However, these effects of quercetin were abolished when NLRC5 was overexpressed. In DN mice, quercetin administration ameliorated renal histopathological injury and fibrosis. Notably, there was a significant reduction in expressions of NLRC5, NLRP3, Col1a1, and α-SMA, along with decreased expressions of pro-inflammatory cytokines (TNF-α, IL-6, and IL-1β).
This study showed that quercetin improves DN by inhibiting M1-type macrophages through targeting the NLRC5/NLRP3 pathway.
M1/M2巨噬细胞表型的激活失衡在糖尿病肾病（DN）中至关重要。本研究旨在探讨槲皮素抗DN作用的分子机制。
在体外，将RAW 264.7巨噬细胞与高糖（HG）共同孵育，同时或不同时添加槲皮素。通过研究NLRC5的过表达来阐明机制。使用细胞表面标志物CD86和CD206通过流式细胞术评估M1/M2巨噬细胞分化。在体内，使用高脂饮食和链脲佐菌素（STZ）建立DN小鼠模型。以50 mg/kg和100 mg/kg的剂量对DN小鼠进行槲皮素灌胃给药。安乐死后，通过苏木精和伊红（H&E）、Masson三色染色和免疫组织化学（IHC）染色对小鼠肾脏进行分析。进行ELISA测定和蛋白质印迹分析以确定相关分子水平。
在体外，槲皮素显著降低了HG诱导的RAW 264.7巨噬细胞中CD86、诱导型一氧化氮合酶（iNOS）、NLRC5、NLRP3和促炎细胞因子（肿瘤坏死因子-α、白细胞介素-6、白细胞介素-1β）的表达，同时增加了HG诱导的CD206、精氨酸酶-1（Arg-1）和白细胞介素-10的表达。然而，当NLRC5过表达时，槲皮素的这些作用被消除。在DN小鼠中，槲皮素给药改善了肾脏组织病理学损伤和纤维化。值得注意的是，NLRC5、NLRP3、I型胶原α1（Col1a1）和α-平滑肌肌动蛋白（α-SMA）的表达显著降低，同时促炎细胞因子（肿瘤坏死因子-α、白细胞介素-6和白细胞介素-1β）的表达也降低。
本研究表明，槲皮素通过靶向NLRC5/NLRP3途径抑制M1型巨噬细胞来改善DN。
