Sutton Arthritis Research Laboratory, Institute of Bone and Joint Research, Sydney, NSW, Australia.
Bill Walsh Translational Cancer Research Laboratory, Kolling Institute of Medical Research, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.
Rheumatology (Oxford). 2021 Jun 18;60(6):2990-3003. doi: 10.1093/rheumatology/keaa701.
Protease-activated receptor (PAR) 1 and PAR2 have been implicated in RA, however their exact role is unclear. Here, we detailed the mechanistic impact of these receptors on the onset and development of inflammatory arthritis in murine CIA and antigen-induced arthritis (AIA) models.
CIA or AIA was induced in PAR1 or PAR2 gene knockout (KO) and matched wild type mice. The onset and development of arthritis was monitored clinically and histologically. Immune cells, cytokines and MMPs were detected by ELISA, zymography, flow cytometry, western blot or immunohistochemistry.
In CIA, PAR1KO and PAR2KO exacerbated arthritis, in opposition to their effects in AIA. These deficient mice had high plasma levels of IL-17, IFN-γ, TGF-β1 and MMP-13, and lower levels of TNF-α; T cells and B cells were higher in both KO spleen and thymus, and myeloid-derived suppressor cells were lower only in PAR1KO spleen, when compared with wild type cells. Th1, Th2 and Th17 cells were lower in PAR1KO spleens cells, whereas Th1 and Th2 cells were lower and Th17 cells higher in both KO thymus cells, when compared with wild type cells. PAR1KO synovial fibroblasts proliferated faster and produced the most abundant MMP-9 amongst three type cells in the control, lipopolysaccharides or TNF stimulated conditions.
This is the first study demonstrated that deficiency of PAR1 or PAR2 aggravates inflammatory arthritis in CIA. Furthermore, the protective functions of PAR1 and PAR2 in CIA likely occur via differing mechanisms involving immune cell differentiation and cytokines/MMPs.
蛋白酶激活受体（PAR）1 和 PAR2 与 RA 有关，但其确切作用尚不清楚。在这里，我们详细研究了这些受体对鼠 CIA 和抗原诱导性关节炎（AIA）模型中炎症性关节炎发病和发展的机制影响。
在 PAR1 或 PAR2 基因敲除（KO）和匹配的野生型小鼠中诱导 CIA 或 AIA。通过临床和组织学监测关节炎的发病和发展。通过 ELISA、凝胶电泳、流式细胞术、western blot 或免疫组织化学检测免疫细胞、细胞因子和 MMP。
在 CIA 中，PAR1KO 和 PAR2KO 加重了关节炎，与它们在 AIA 中的作用相反。这些缺乏型小鼠的血浆 IL-17、IFN-γ、TGF-β1 和 MMP-13 水平较高，TNF-α水平较低；与野生型细胞相比，KO 脾和胸腺中的 T 细胞和 B 细胞更高，而髓源抑制细胞仅在 PAR1KO 脾中较低。与野生型细胞相比，PAR1KO 脾细胞中的 Th1、Th2 和 Th17 细胞较低，而 PAR1KO 和 PAR2KO 胸腺细胞中的 Th1 和 Th2 细胞较低，Th17 细胞较高。PAR1KO 滑膜成纤维细胞在对照、脂多糖或 TNF 刺激条件下增殖速度更快，产生的 MMP-9 最多。
这是第一项研究表明，PAR1 或 PAR2 的缺乏会加重 CIA 中的炎症性关节炎。此外，PAR1 和 PAR2 在 CIA 中的保护作用可能通过涉及免疫细胞分化和细胞因子/MMP 的不同机制发生。
