Sun Lihua, Niu Yajuan, Liao Bo, Liu Linlin, Peng Yi, Li Kaiting, Chen Xinhua, Chen Qing, Bai Dingqun
Department of Rehabilitation Medicine, Key Laboratory of Physical Medicine and Precision Rehabilitation of Chongqing Municipal Health Commission, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400010, China.
The Chongqing Key Laboratory of Translational Medicine in Major Metabolic Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, People's Republic of China.
Inflamm Res. 2025 Mar 14;74(1):53. doi: 10.1007/s00011-025-02019-2.
Ferroptosis is a non-apoptotic cell death mechanism driven by reactive oxygen species (ROS) and iron. Its significance in inflammatory arthritis is well-established, but its role in rheumatoid arthritis (RA) remains uncertain. This study aimed to clarify the mechanisms through which curcumin-mediated photodynamic therapy (CUR-PDT) triggers ferroptosis in RA fibroblast-like synoviocytes (FLSs).
In vivo studies using a collagen-induced arthritis (CIA) rat model evaluated CUR-PDT effects on joint edema, synovial inflammation, and fibrosis through paw volume measurements and H&E and Masson's trichrome staining. The expression of Nrf2, xCT, and GPX4 in FLSs was assessed via ELISA and immunohistochemistry. In vitro, MH7A cells treated with TNF-α were analyzed for viability, proliferation, invasion, and migration through various assays. Mitochondrial potential and morphology were examined using JC-1 staining and transmission electron microscopy (TEM). Ferroptosis biomarkers, including ROS, malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), and Fe levels, were measured. Nrf2, xCT, and GPX4 levels were quantified with RT-qPCR, Western blot, and immunofluorescence. Small interfering RNA (siRNA) was employed to knock down Nrf2 to validate the effect of CUR-PDT on ferroptosis in RA-FLS.
The CUR-PDT therapy markedly reduced joint inflammation and collagen deposition in the synovial tissue of CIA rats. It effectively alleviated both inflammation and hyperplasia. Moreover, this therapy facilitated ferroptosis within the synovial tissue. In vitro analyses indicated that CUR-PDT diminished the proliferation and viability of FLSs, resulting in increased ROS levels in the cells. This cascade initiated ferroptosis, as evidenced by decreased glutathione, heightened iron concentrations, mitochondrial shrinkage, and reduced mitochondrial membrane potential. Crucially, the expression of xCT and GPX4 was significantly lowered. Interestingly, knocking down the Nrf2 gene amplified this effect, leading to an even greater reduction in xCT and GPX4 expression. In this context, RA-FLSs exhibited more pronounced ferroptotic traits, including diminished proliferation, invasion, and migration.
This study elucidated a mechanism by which CUR-PDT triggers ferroptosis in FLSs through the downregulation of the Nrf2-xCT-GPX4 signaling cascade, thereby effectively hindering the progression of RA and emphasizing the importance of targeting Nrf2 in disease advancement.
铁死亡是一种由活性氧（ROS）和铁驱动的非凋亡性细胞死亡机制。其在炎性关节炎中的意义已得到充分证实，但其在类风湿关节炎（RA）中的作用仍不确定。本研究旨在阐明姜黄素介导的光动力疗法（CUR-PDT）触发RA成纤维样滑膜细胞（FLS）铁死亡的机制。
使用胶原诱导性关节炎（CIA）大鼠模型进行体内研究，通过测量爪体积以及苏木精-伊红（H&E）和Masson三色染色评估CUR-PDT对关节水肿、滑膜炎症和纤维化的影响。通过酶联免疫吸附测定（ELISA）和免疫组织化学评估FLS中核因子E2相关因子2（Nrf2）、溶质载体家族7成员11（xCT）和谷胱甘肽过氧化物酶4（GPX4）的表达。在体外，通过各种检测分析用肿瘤坏死因子-α（TNF-α）处理的MH7A细胞的活力、增殖、侵袭和迁移。使用JC-1染色和透射电子显微镜（TEM）检查线粒体电位和形态。测量铁死亡生物标志物，包括ROS、丙二醛（MDA）、谷胱甘肽（GSH）、超氧化物歧化酶（SOD）和铁水平。用逆转录定量聚合酶链反应（RT-qPCR）、蛋白质免疫印迹法和免疫荧光法定量Nrf2、xCT和GPX4水平。采用小干扰RNA（siRNA）敲低Nrf2以验证CUR-PDT对RA-FLS铁死亡的影响。
CUR-PDT疗法显著减轻了CIA大鼠滑膜组织中的关节炎症和胶原沉积。它有效缓解了炎症和增生。此外，该疗法促进了滑膜组织内的铁死亡。体外分析表明，CUR-PDT降低了FLS的增殖和活力，导致细胞内ROS水平升高。这种级联反应引发了铁死亡，表现为谷胱甘肽减少、铁浓度升高、线粒体萎缩和线粒体膜电位降低。至关重要的是，xCT和GPX4的表达显著降低。有趣的是，敲低Nrf2基因放大了这种效应，导致xCT和GPX4表达进一步降低。在此背景下，RA-FLS表现出更明显的铁死亡特征，包括增殖、侵袭和迁移减少。
本研究阐明了一种机制，即CUR-PDT通过下调Nrf2-xCT-GPX4信号级联反应触发FLS中的铁死亡，从而有效阻碍RA的进展，并强调了靶向Nrf2在疾病进展中的重要性。
