PT  - JOURNAL ARTICLE
AU  - Hidetoshi Tsushima
AU  - Ken Okazaki
AU  - Mitsumasa Hayashida
AU  - Takahiro Ushijima
AU  - Yukihide Iwamoto
TI  - CCAAT/enhancer binding protein β regulates expression of matrix metalloproteinase-3 in arthritis
AID  - 10.1136/annrheumdis-2011-200061
DP  - 2012 Jan 01
TA  - Annals of the Rheumatic Diseases
PG  - 99--107
VI  - 71
IP  - 1
4099  - http://ard.bmj.com/content/71/1/99.short
4100  - http://ard.bmj.com/content/71/1/99.full
SO  - Ann Rheum Dis2012 Jan 01; 71
AB  - Objectives To investigate whether CCAAT/enhancer binding protein β (C/EBPβ) mediates the expression of matrix metalloproteinase-3 (MMP-3) and aggrecanases in arthritis. Methods Localisation of C/EBPβ and MMP-3 in synovium and cartilage from patients with rheumatoid arthritis and osteoarthritis was determined by immunohistochemistry. Cell lines SW982, C28/I2 and human fibroblast-like synoviocytes stimulated by interleukin 1β (IL-1β) were subjected to western blotting and quantitative PCR. Overexpression of C/EBPβ by adenovirus was performed in cells and organ culture of normal cartilage. Knockdown of C/EBPβ by small interference RNA was performed in cells. Activity of the human MMP-3 and aggrecanase-2 ADAMTS-5 (a disintegrin and metalloproteinase with thrombospondin motifs) promoters was analysed by a luciferase assay. To determine whether C/EBPβ directly binds to the MMP-3 or ADAMTS-5 promoter,a chromatin immunoprecipitation assay was performed. Results Immunohistochemistry showed that C/EBPβ and MMP-3 were co-localised in arthritic synovium and cartilage. Western blots revealed increased C/EBPβ expression in cells treated with IL-1β. Expression of MMP-3, MMP-13 and ADAMTS-5 mRNA was significantly increased by the overexpression of C/EBPβ. C/EBPβ stimulated MMP-3 expression and induced matrix degradation in cartilage explants. C/EBPβ knockdown reduced MMP-3 and ADAMTS-5 expression. C/EBPβ stimulated the 2011 bp MMP-3 promoter and the 1768 bp ADAMTS-5 promoter in a dose-dependent manner. Deletion and mutation analysis of the MMP-3 promoter showed that the C/EBPβ core responsive element was located between −108 bp and −100 bp. The chromatin immunoprecipitation assay showed that C/EBPβ was directly bound to MMP-3 and ADAMTS-5 promoters. Conclusions These data demonstrate that C/EBPβ is involved in expression of MMP-3 and ADAMTS-5 in arthritic synovium and cartilage.