title: Differential expression of WNTs and FRPs in the synovium of rheumatoid arthritis and osteoarthritis.
abstract: Synovial cells of the joint play a key role in the progression of rheumatoid arthritis (RA). However, the mechanism(s) that triggers aggression of RA synovial cells but not other arthropathies such as osteoarthritis (OA) is not clear. Here we examined expression of WNT and the WNT inhibitor, secreted frizzled-related protein (FRP), in RA and OA synovium by reverse transcription-PCR. WNT10B was most frequently detected in RA synovium, and FRP1, FRP2, and FRP4 in OA synovium. Immunohistochemistry localized WNT10B and FRP1 in synovial lining cells, fibroblasts, and endothelial cells in RA and OA synovium, respectively, and WNT10B expression was increased in parallel with the degree of inflammatory cell infiltration and tissue fibrosis. Membrane-type 1 matrix metalloproteinse (MT1MMP) was upregulated by WNT10B and activation of WNT signaling. MT1MMP immunolocalized to cells identical to WNT10B and beta-catenin staining. The present study demonstrated that WNTs and FRPs are differentially expressed in RA and OA synovium, and suggests an involvement in the pathology of these diseases.
authors.affiliation: Department of Biochemistry, School of Life Dentistry at Tokyo, The Nippon Dental University, Japan. KIMAI@Tokyo.ndu.ac.jp
authors.forename: Kazushi
authors.initials: K
authors.lastname: Imai
authors.forename: Masako
authors.initials: M
authors.lastname: Morikawa
authors.forename: Jeanine
authors.initials: J
authors.lastname: D'Armiento
authors.forename: Hideo
authors.initials: H
authors.lastname: Matsumoto
authors.forename: Koichiro
authors.initials: K
authors.lastname: Komiya
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Okada
mesh_terms: D001172:Arthritis, Rheumatoid / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D020869:Gene Expression Profiling; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics* / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000235:genetics / Q000378:metabolism; D053504:Matrix Metalloproteinases, Membrane-Associated; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D010003:Osteoarthritis / Q000235:genetics* / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013583:Synovial Membrane / Q000378:metabolism* / Q000473:pathology; D051153:Wnt Proteins / Q000235:genetics* / Q000378:metabolism; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism; D000094742:Secreted Frizzled-Related Proteins
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D020782:Matrix Metalloproteinases; D053504:Matrix Metalloproteinases, Membrane-Associated; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D051153:Wnt Proteins; D051176:beta Catenin; C117636:SFRP1 protein, human; D000094742:Secreted Frizzled-Related Proteins; C109618:SFRP2 protein, human; C491119:WNT10B protein, human