title: Beta-catenin regulates expression of cyclooxygenase-2 in articular chondrocytes.
abstract: Pro-inflammatory cytokine such as interleukin (IL)-1beta causes inflammation of articular cartilage via induction of cyclooxygenase (COX)-2 expression. We investigated in this study the role of beta-catenin in the IL-1beta regulation of COX-2 expression in articular chondrocytes. IL-1beta increased expression of COX-2 and induced accumulation and nuclear translocation of transcriptionally competent beta-catenin. Inhibition of beta-catenin degradation by the treatment of cells with LiCl or proteasome inhibitor stimulated expression of COX-2, indicating that transcriptionally active beta-catenin is sufficient to induce COX-2 expression. This was demonstrated further by the observation that ectopic expression of transcriptionally competent beta-catenin stimulated expression of COX-2. Levels of beta-catenin and COX-2 protein were increased in osteoarthritic and rheumatoid arthritic cartilage, suggesting that beta-catenin may play a role in the inflammatory responses of arthritic cartilage. Taken together, our data suggest that accumulation of transcriptionally active beta-catenin contributes to the expression of COX-2 in articular chondrocytes.
authors.affiliation: Department of Life Science, Kwangju Institute of Science and Technology, 500-712, Gwangju, Republic of Korea.
authors.forename: Song Ja
authors.initials: SJ
authors.lastname: Kim
authors.forename: Dae Seong
authors.initials: DS
authors.lastname: Im
authors.forename: Seon Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Je Hwang
authors.initials: JH
authors.lastname: Ryu
authors.forename: Sang Gu
authors.initials: SG
authors.lastname: Hwang
authors.forename: Je Kyung
authors.initials: JK
authors.lastname: Seong
authors.forename: Churl Hong
authors.initials: CH
authors.lastname: Chun
authors.forename: Jang Soo
authors.initials: JS
authors.lastname: Chun
mesh_terms: D000818:Animals; D001168:Arthritis / Q000201:enzymology / Q000378:metabolism; D002358:Cartilage, Articular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D003598:Cytoskeletal Proteins / Q000378:metabolism / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D007375:Interleukin-1 / Q000494:pharmacology; D007527:Isoenzymes / Q000235:genetics*; D011451:Prostaglandin-Endoperoxide Synthases / Q000235:genetics*; D011817:Rabbits; D015534:Trans-Activators / Q000378:metabolism / Q000502:physiology*; D015533:Transcriptional Activation / Q000187:drug effects; D051176:beta Catenin
chemical_list: D003598:Cytoskeletal Proteins; D007375:Interleukin-1; D007527:Isoenzymes; D015534:Trans-Activators; D051176:beta Catenin; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases