Open AccessInterleukin‐4 suppression of interleukin‐1‐induced transcription of collagenase (MMP‐1) and stromelysin 1 (MMP‐3) in human synovial fibroblasts
Author(s) -
Borghaei Ruth Carter,
Rawlings P. Lyle,
Mochan Eugene
Publication year - 1998
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/1529-0131(199808)41:8<1398::aid-art8>3.0.co;2-b
Subject(s) - microbiology and biotechnology , interstitial collagenase , northern blot , matrix metalloproteinase , western blot , collagenase , messenger rna , interleukin , prostaglandin e2 , fibroblast , chemistry , cytokine , biology , endocrinology , enzyme , immunology , biochemistry , gene , in vitro
Objective To determine the effects of interleukin‐4 (IL‐4) on IL‐1 induction of collagenase (matrix metalloproteinase 1 [MMP‐1]) and stromelysin‐1 (MMP‐3) in human synovial fibroblasts. Methods Northern blot analysis was performed to determine the effects of IL‐4 on IL‐1 induction of MMP messenger RNA (mRNA). MMP protein levels were determined by enzyme‐linked immunosorbent assay, and prostaglandin E 2 (PGE 2 ) levels were measured by enzyme immunoassay. Run‐on transcription assays and transient transfection experiments were performed to determine whether the effects of IL‐4 occur at the level of transcription. Activator protein 1 (AP‐1) binding was assessed by electrophoretic mobility shift assay. Results Northern blot analysis revealed that co‐incubation of synovial fibroblasts with IL‐1 and IL‐4 resulted in a significant decrease in both collagenase and stromelysin mRNA levels compared with IL‐1 alone, with a concomitant decrease in MMP protein levels. This inhibition is dose dependent, with an IC 50 (50% inhibition concentration) for both MMPs of ∼0.3 ng of IL‐4 per ml, and is at least somewhat selective, since IL‐1 induction of c‐ fos mRNA is not affected. Nuclear run‐on experiments and transient transfection studies demonstrated that the suppression of IL‐1‐induced collagenase and stromelysin expression by IL‐4 occurs at least in part at the transcriptional level, and that binding of transcription factor AP‐1 is not affected. Although IL‐1‐induced levels of PGE 2 are reduced by IL‐4, exogenous addition of PGE 2 does not abrogate the inhibitory effects of IL‐4 on MMP expression. Conclusion IL‐4 inhibits IL‐1 induction of both collagenase and stromelysin, as well as PGE 2 production, in human synovial fibroblasts. The inhibition occurs at least in part at the level of transcription, does not affect binding of transcription factor AP‐1, and appears to involve a mechanism that is independent of the ability of IL‐4 to inhibit production of PGE 2 .