Xin Chang1, Jirong Shen2, Haiwei Yang1, Yanan Xu3, Wei Gao3, Junling Wang3, Huiyun Zhang4, Shaoheng He5. 1. Clinical Research Centre, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China. 2. Department of Orthopaedics, Affiliated Hospital of Nanjing University of TCM, Nanjing, Jiangsu 210029, China. 3. Allergy and Clinical Immunology Research Centre, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121001, China. 4. Allergy and Clinical Immunology Research Centre, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121001, China; Central Laboratory of Suzhou Xiangcheng People's Hospital, Suzhou, Jiangsu 215131, China. Electronic address: zhanghuiyun2003@126.com. 5. Clinical Research Centre, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, China; Allergy and Clinical Immunology Research Centre, The First Affiliated Hospital of Liaoning Medical University, Jinzhou, Liaoning 121001, China. Electronic address: shoahenghe@hotmail.com.
Abstract
OBJECTIVES: Upregulated expression of CC chemokine receptor (CCR)3 was observed in osteoarthritis (OA) cartilage and chondrocytes, but expression of CCR3 on synovial tissue of OA remains unknown. Fibroblast-like synoviocyte (FLS) invasion in synovium appears one of the features of OA, but expression and function of CCR3 on FLS remain uninvestigated. We therefore explored them in the present study. METHODS: Enzymatically dispersed synovial tissue cells were analyzed by flowcytometry. Primary cultured FLS isolated from OA synovium were challenged and the expression of CCR3, eotaxin-1 and matrix metalloproteinase (MMP)-9 was determined by quantitative real-time PCR (qPCR) and ELISA. RESULTS: Approximately 4.5% dispersed OA synovial tissue cells are CCR3+ cells. Among them, 58.4% cells are CD90+CD14-CD3- cells (representing FLS) and 36.7% are CD8+ cells, indicating that FLS are major population of CCR3+ cells in the synovial tissue. Levels of eotaxin-1 and MMP-9 in OA synovial fluid (SF) were greater than that in OA plasma and in healthy control (HC) plasma. Eotaxin-1 induced up to 5.8 and 7.2-fold increases in the expression of MMP-9 mRNA and protein, respectively following 12h incubation with FLS, which was inhibited by antagonist of CCR3 SB328437 and an inhibitor of ERK U0126, indicating that action of eotaxin-1 on FLS seemed via CCR3 and ERK signaling pathway. IL-1β and TNF-α was found to elicit release of eotaxin-1 from OA FLS. CONCLUSION: FLS via eotaxin-1 and its receptor CCR3 plays an important role in the pathogenesis of OA, which strengthen the concept that OA is likely an inflammation related disease.
OBJECTIVES: Upregulated expression of CC chemokine receptor (CCR)3 was observed in osteoarthritis (OA) cartilage and chondrocytes, but expression of CCR3 on synovial tissue of OA remains unknown. Fibroblast-like synoviocyte (FLS) invasion in synovium appears one of the features of OA, but expression and function of CCR3 on FLS remain uninvestigated. We therefore explored them in the present study. METHODS: Enzymatically dispersed synovial tissue cells were analyzed by flowcytometry. Primary cultured FLS isolated from OA synovium were challenged and the expression of CCR3, eotaxin-1 and matrix metalloproteinase (MMP)-9 was determined by quantitative real-time PCR (qPCR) and ELISA. RESULTS: Approximately 4.5% dispersed OA synovial tissue cells are CCR3+ cells. Among them, 58.4% cells are CD90+CD14-CD3- cells (representing FLS) and 36.7% are CD8+ cells, indicating that FLS are major population of CCR3+ cells in the synovial tissue. Levels of eotaxin-1 and MMP-9 in OA synovial fluid (SF) were greater than that in OA plasma and in healthy control (HC) plasma. Eotaxin-1 induced up to 5.8 and 7.2-fold increases in the expression of MMP-9 mRNA and protein, respectively following 12h incubation with FLS, which was inhibited by antagonist of CCR3SB328437 and an inhibitor of ERKU0126, indicating that action of eotaxin-1 on FLS seemed via CCR3 and ERK signaling pathway. IL-1β and TNF-α was found to elicit release of eotaxin-1 from OA FLS. CONCLUSION: FLS via eotaxin-1 and its receptor CCR3 plays an important role in the pathogenesis of OA, which strengthen the concept that OA is likely an inflammation related disease.