Induction of macrophage migration inhibitory factor in ConA-stimulated rheumatoid arthritis synovial fibroblasts through the P38 map kinase-dependent signaling pathway.
OBJECTIVE
This study was undertaken to identify the intracellular signaling pathway involved in induction of macrophage migration inhibitory factor (MIF) in human rheumatoid arthritis (RA) synovial fibroblasts.


METHODS
Human RA synovial fibroblasts were treated with concanavalin A (ConA), various cytokines, and inhibitors of signal transduction molecules. The production of MIF by synovial fibroblasts was measured in culture supernatants by ELISA. The expression of MIF mRNA was determined using reverse transcriptase polymerase chain reaction (RT-PCR) and real-time PCR. Phosphorylation of p38 mitogen-activated protein (MAP) kinase in synovial fibroblasts was confirmed using Western blotting. The expression of MIF and p38 MAP kinase in RA synovium was determined using dual immunohistochemistry.


RESULTS
The production of MIF by RA synovial fibroblasts increased in a dose-dependent manner after ConA stimulation. MIF was also induced by interferon-γ, CD40 ligand, interleukin-15, interleukin-1β, tumor necrosis factor-α, and transforming growth factor-β. The production of MIF by RA synovial fibroblasts was significantly reduced after inhibition of p38 MAP kinase. The expression of MIF and p38 MAP kinase was upregulated in the RA synovium compared with the osteoarthritis synovium.


CONCLUSIONS
These results suggest that MIF production was induced through a p38 MAP-kinase-dependent pathway in RA synovial fibroblasts.
Kim
Hae-Rim
HR
Division of Rheumatology, Department of Internal Medicine, Konkuk University School of Medicine Seoul, Korea.
Park
Mi-Kyung
MK
Cho
Mi-La
ML
Kim
Kyoung-Woon
KW
Oh
Hye-Joa
HJ
Park
Jin-Sil
JS
Heo
Yang-Mi
YM
Lee
Sang-Heon
SH
Kim
Ho-Youn
HY
Park
Sung-Hwan
SH
D001172:Arthritis, Rheumatoid / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D017931:DNA Primers / Q000235:genetics; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008263:Macrophage Migration-Inhibitory Factors / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013583:Synovial Membrane / Q000187:drug effects / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D016207:Cytokines; D017931:DNA Primers; D008263:Macrophage Migration-Inhibitory Factors; D012333:RNA, Messenger; D003208:Concanavalin A; D048051:p38 Mitogen-Activated Protein Kinases