Cheng Yu, Si Yuying, Wang Lan, Ding Menglei, Yu Shanshan, Lu Liu, Guo Yide, Zong Ming, Fan Lieying
Department of Clinical Laboratory, Shanghai East Hospital, 150 Ji Mo Road, Shanghai 200120, People's Republic of China.
Department of Clinical Laboratory, Shanghai East Hospital, 150 Ji Mo Road, Shanghai 200120, People's Republic of China.
Int Immunopharmacol. 2021 Oct;99:107988. doi: 10.1016/j.intimp.2021.107988. Epub 2021 Jul 29.
Hypoxia, a common feature of rheumatoid arthritis (RA), induces the over-expression of peptidyl arginine deiminase 4 (PADI4) in fibroblast-like synoviocytes (FLSs) and macrophages. However, the roles of PADI4 and its inducer hypoxia in the regulation of macrophage polarization remain unclear. This study aimed to investigate the role of hypoxia-PADI4 for macrophage polarization in RA patients.
Synovial tissue (ST) and synovial fluid (SF) were collected from 3 OA patients and 6 RA patients. The distribution of M1 and M2 in ST and cytokines in SF were examined by immunohistochemical analysis and Bio-Plex immunoassays. THP-1 macrophages and BMDM polarization were determined under normoxic (21% oxygen) or hypoxic (3% oxygen) conditions. The effects of PADI4 on macrophages were determined by transfection of adenovirus vector-coated PADI4 (AdPADI4) and the use of PADI4 inhibitor. Finally, the roles of PADI4 in joint synovial lesions on macrophage polarization were investigated in collagen-induced arthritis (CIA) rats.
We found increased macrophage polarization of M1 and M2 in the RA ST, compared with OA ST. The ratio of M1/M2 for RA and OA was 1.633 ± 0.1443 and 2.544 ± 0.4429, respectively. The concentration of M1- and M2-type cytokines was higher in RA than that in OA patients. Hypoxia contributed to the increase of the gene and protein expression of M1 and M2 markers. M1- but not M2-type gene expression showed a positive relationship with PADI4 expressionwhile the level of expression of M2-type genes showed no significant difference. The degree of joint swelling and destruction was effectively alleviated, and the number of macrophages especially M1 decreased in CIA rats after down-regulating PADI4 expression.
Hypoxia is responsible for the co-polarization of M1 and M2. Hypoxia-associated PADI4 is responsible for M1 macrophage activation, implying that the inflammatory environment can be eased by decreasing PADI4 expression and improving the hypoxic environment.
缺氧是类风湿关节炎（RA）的一个常见特征，可诱导成纤维样滑膜细胞（FLS）和巨噬细胞中肽基精氨酸脱亚氨酶4（PADI4）的过度表达。然而，PADI4及其诱导剂缺氧在巨噬细胞极化调节中的作用仍不清楚。本研究旨在探讨缺氧-PADI4在RA患者巨噬细胞极化中的作用。
收集3例骨关节炎（OA）患者和6例RA患者的滑膜组织（ST）和滑液（SF）。通过免疫组织化学分析和生物芯片免疫测定法检测ST中M1和M2的分布以及SF中的细胞因子。在常氧（21%氧气）或缺氧（3%氧气）条件下测定THP-1巨噬细胞和骨髓来源巨噬细胞（BMDM）的极化。通过转染腺病毒载体包被的PADI4（AdPADI4）和使用PADI4抑制剂来确定PADI4对巨噬细胞的影响。最后，在胶原诱导的关节炎（CIA）大鼠中研究PADI4在关节滑膜病变中对巨噬细胞极化的作用。
我们发现，与OA的ST相比，RA的ST中M1和M2的巨噬细胞极化增加。RA和OA的M1/M2比值分别为1.633±0.1443和2.544±0.4429。RA患者中M1型和M2型细胞因子的浓度高于OA患者。缺氧导致M1和M2标志物的基因和蛋白表达增加。M1型而非M2型基因表达与PADI4表达呈正相关，而M2型基因的表达水平无显著差异。下调PADI4表达后，CIA大鼠的关节肿胀和破坏程度得到有效缓解，巨噬细胞数量尤其是M1减少。
缺氧导致M1和M2的共极化。缺氧相关的PADI4导致M1巨噬细胞活化，这意味着通过降低PADI4表达和改善缺氧环境可以缓解炎症环境。
