title: LIGHT is involved in the pathogenesis of rheumatoid arthritis by inducing the expression of pro-inflammatory cytokines and MMP-9 in macrophages.
abstract: Macrophages play a crucial role in the perpetuation of inflammation and irreversible cartilage damage during the development of rheumatoid arthritis (RA). LIGHT (TNFSF14) and its receptor TR2 (TNFRSF14) are known to have pro-inflammatory activities in foam cells of atherosclerotic plaques. We tested a hypothesis that LIGHT and TR2 are involved in activation of monocyte/macrophages in RA synovium. Immunohistochemical analysis of RA synovial tissue samples revealed that both LIGHT and TR2 are expressed in CD68 positive macrophages. In contrast, synovial tissue samples from osteoarthritis (OA) patients failed to reveal the expression of LIGHT. Expression of TR2 in RA synovial macrophages was also detected using flow cytometry analysis. To identify the role of LIGHT in the functioning of macrophages in RA, we isolated macrophage enriched cells from RA synovial fluid and stimulated them with LIGHT. LIGHT induced expression of matrix metalloproteinase-9 and pro-inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-8. These data indicate that LIGHT and TR2 expressed in macrophages are involved in the pathogenesis of RA by inducing the expression pro-inflammatory cytokines and matrix degrading enzymes.
authors.affiliation: Department of Genetic Engineering, Kyungpook National University, Taegu 702-701, Korea.
authors.forename: Won-Jung
authors.initials: WJ
authors.lastname: Kim
authors.forename: Yoon-Joong
authors.initials: YJ
authors.lastname: Kang
authors.forename: Eun-Mi
authors.initials: EM
authors.lastname: Koh
authors.forename: Kwang-Sung
authors.initials: KS
authors.lastname: Ahn
authors.forename: Hoon-Suk
authors.initials: HS
authors.lastname: Cha
authors.forename: Won-Ha
authors.initials: WH
authors.lastname: Lee
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001172:Arthritis, Rheumatoid / Q000276:immunology*; D016207:Cytokines / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007211:Indoles / Q000032:analysis / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology / Q000276:immunology*; D020780:Matrix Metalloproteinase 9 / Q000032:analysis / Q000378:metabolism*; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism*; D013583:Synovial Membrane / Q000276:immunology*; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism*; D000097382:CD68 Molecule
chemical_list: D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D016207:Cytokines; D007211:Indoles; D020780:Matrix Metalloproteinase 9; D008565:Membrane Proteins; D053326:Tumor Necrosis Factor Ligand Superfamily Member 14; D014409:Tumor Necrosis Factor-alpha; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C505914:TNFSF14 protein, human; C039287:TR-2 mycotoxin