title: CITED2-mediated regulation of MMP-1 and MMP-13 in human chondrocytes under flow shear.
abstract: CITED2 (CBP/p300-interacting transactivator with ED-rich tail 2) is a member of the Cited family of nuclear regulators, previously known as mrg1 (melanocyte-specific gene-related gene 1). CITED2 is inducible by varying stimuli including lipopolysaccharide, hypoxia, and cytokines such as interleukin 9 and interferon gamma. Using the immortalized human chondrocyte cell line, C-28/I2, we investigated whether CITED2 could be responsive to mechanical stimuli, and if so, whether CITED2 could mediate shear-driven regulation of matrix metalloproteinase (MMP) genes. The C-28/I2 cells were cultured under flow shear at 1-20 dyn/cm2, and the role of CIT-ED2 in regulation of MMPs was examined using the plasmids encoding sense and antisense CITED2 DNA sequences. The results showed that flow shear at 5 dyn/cm2 increased CITED2 mRNA and protein levels and down-regulated MMP-1 and MMP-13 mRNA and protein levels as well as enzyme activities. Consistent with the coordinated expression patterns of CITED2 and MMPs, overexpression of CITED2 repressed MMP-1 and MMP-13 mRNA levels and activities, whereas antisense CITED2 plasmids prevented the shear-induced down-regulation of MMP expression. Interleukin-1beta induced the formation of p300-Ets-1 complexes without affecting expression of CITED2. Transforming growth factor-beta as well as flow shear at 5 dyn/cm2 stimulated not only the expression of CITED2 but also the association of CIT-ED2 with p300 by dissociating Ets-1 from p300. These results indicate that CITED2 plays a major role in shear-induced down-regulation of MMP-1 and MMP-13 via a transforming growth factor-beta-dependent pathway.
authors.affiliation: Biomedical Engineering Program, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yokota
authors.forename: Mary B
authors.initials: MB
authors.lastname: Goldring
authors.forename: Hui Bin
authors.initials: HB
authors.lastname: Sun
mesh_terms: D002460:Cell Line; D019902:Chondrocytes / Q000378:metabolism*; D017364:Collagenases / Q000096:biosynthesis* / Q000235:genetics; D004268:DNA-Binding Proteins; D015536:Down-Regulation; D006801:Humans; D020781:Matrix Metalloproteinase 1 / Q000096:biosynthesis* / Q000235:genetics; D053509:Matrix Metalloproteinase 13; D009687:Nuclear Proteins / Q000378:metabolism; D010477:Perfusion; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D050783:Proto-Oncogene Proteins c-ets; D012333:RNA, Messenger / Q000032:analysis; D012097:Repressor Proteins; D013314:Stress, Mechanical; D015534:Trans-Activators / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000494:pharmacology
chemical_list: C486381:CITED2 protein, human; D004268:DNA-Binding Proteins; C494041:ETS1 protein, human; D009687:Nuclear Proteins; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D012333:RNA, Messenger; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; D020781:Matrix Metalloproteinase 1