Abji Fatima, Rasti Mozhgan, Gómez-Aristizábal Alejandro, Muytjens Carla, Saifeddine Mahmoud, Mihara Koichiro, Motahhari Majid, Gandhi Rajiv, Viswanathan Sowmya, Hollenberg Morley D, Oikonomopoulou Katerina, Chandran Vinod
Schroeder Arthritis Institute, Krembil Research Institute, University Health Network, Toronto, ON, Canada.
Department of Physiology & Pharmacology, University of Calgary Cumming School of Medicine, Calgary, AB, Canada.
Front Immunol. 2021 Mar 8;11:629726. doi: 10.3389/fimmu.2020.629726. eCollection 2020.
Multiple proteinases are present in the synovial fluid (SF) of an arthritic joint. We aimed to identify inflammatory cell populations present in psoriatic arthritis (PsA) SF compared to osteoarthritis (OA) and rheumatoid arthritis (RA), identify their proteinase-activated receptor 2 (PAR2) signaling function and characterize potentially active SF serine proteinases that may be PAR2 activators.
Flow cytometry was used to characterize SF cells from PsA, RA, OA patients; PsA SF cells were further characterized by single cell 3'-RNA-sequencing. Active serine proteinases were identified through cleavage of fluorogenic trypsin- and chymotrypsin-like substrates, activity-based probe analysis and proteomics. Fluo-4 AM was used to monitor intracellular calcium cell signaling. Cytokine expression was evaluated using a multiplex Luminex panel.
PsA SF cells were dominated by monocytes/macrophages, which consisted of three populations representing classical, non-classical and intermediate cells. The classical monocytes/macrophages were reduced in PsA compared to OA/RA, whilst the intermediate population was increased. PAR2 was elevated in OA vs. PsA/RA SF monocytes/macrophages, particularly in the intermediate population. PAR2 expression and signaling in primary PsA monocytes/macrophages significantly impacted the production of monocyte chemoattractant protein-1 (MCP-1). Trypsin-like serine proteinase activity was elevated in PsA and RA SF compared to OA, while chymotrypsin-like activity was elevated in RA compared to PsA. Tryptase-6 was identified as an active serine proteinase in SF that could trigger calcium signaling partially PAR2.
PAR2 and its activating proteinases, including tryptase-6, can be important mediators of inflammation in PsA. Components within this proteinase-receptor axis may represent novel therapeutic targets.
关节炎关节的滑液（SF）中存在多种蛋白酶。我们旨在确定与骨关节炎（OA）和类风湿关节炎（RA）相比，银屑病关节炎（PsA）滑液中存在的炎症细胞群，确定其蛋白酶激活受体2（PAR2）信号传导功能，并鉴定可能是PAR2激活剂的潜在活性滑液丝氨酸蛋白酶。
采用流式细胞术对PsA、RA、OA患者的滑液细胞进行表征；通过单细胞3'-RNA测序对PsA滑液细胞进行进一步表征。通过荧光胰蛋白酶和糜蛋白酶样底物的切割、基于活性的探针分析和蛋白质组学鉴定活性丝氨酸蛋白酶。使用Fluo-4 AM监测细胞内钙信号传导。使用多重Luminex检测法评估细胞因子表达。
PsA滑液细胞以单核细胞/巨噬细胞为主，由代表经典、非经典和中间细胞的三个群体组成。与OA/RA相比，PsA中的经典单核细胞/巨噬细胞减少，而中间群体增加。OA与PsA/RA滑液单核细胞/巨噬细胞相比，PAR2升高，特别是在中间群体中。原发性PsA单核细胞/巨噬细胞中PAR2的表达和信号传导显著影响单核细胞趋化蛋白-1（MCP-1）的产生。与OA相比，PsA和RA滑液中的胰蛋白酶样丝氨酸蛋白酶活性升高，而与PsA相比，RA中的糜蛋白酶样活性升高。类胰蛋白酶-6被鉴定为滑液中的一种活性丝氨酸蛋白酶，可部分通过PAR2触发钙信号。
PAR2及其激活蛋白酶，包括类胰蛋白酶-6，可能是PsA炎症的重要介质。该蛋白酶-受体轴中的成分可能代表新的治疗靶点。
