title: TAK1 downregulation reduces IL-1beta induced expression of MMP13, MMP1 and TNF-alpha.
abstract: The paper provides evidence that transforming growth factor-beta activated kinase 1 (TAK1, MEKK7), a downstream mediator of IL-1beta signal transduction, plays an important role in the regulation of catabolic events and inflammatory processes in the context of degenerative joint diseases. We investigated the expression of TAK1 in human articular chondrocytes and in the murine growth plate by cDNA array, quantitative RT-PCR and immunohistochemistry, respectively. The human chondrosarcoma cell line SW1353 was stimulated with the proinflammatory cytokine IL-1beta. The subsequent expression of proteolytic enzymes and proinflammatory cytokines was quantified. TAK1 specific siRNA was used to study the influence of TAK1 downregulation on the expression of MMP-13, MMP1 and TNF-alpha. As a result we demonstrated the expression of TAK1 in normal and osteoarthritic human articular cartilage. Expression of TAK1 in the hypertrophic zone of the growth plate gave us a first evidence for a catabolic function of TAK1 concerning cartilage metabolism. By gene suppression with RNAi technology we could show that TAK1 downregulation leads to a 60-70% reduced release of TNF-alpha, a 40-50% reduced release of MMP13, and a 20-30% reduction of MMP1 release. As TNF-alpha is a main player in inflammatory processes, and MMP13 is one of the major proteases involved in cartilage degradation, our results suggests that TAK1 has an important regulatory role in the context of degenerative joint diseases and thus is an attractive drug target in attempts to reduce inflammation and suppress structural changes in OA induced by IL-1beta.
authors.affiliation: Institut für Klinische Chemie, University of Cologne, Germany.
authors.forename: Andreas R
authors.initials: AR
authors.lastname: Klatt
authors.forename: Gabriele
authors.initials: G
authors.lastname: Klinger
authors.forename: Olga
authors.initials: O
authors.lastname: Neumüller
authors.forename: Bernd
authors.initials: B
authors.lastname: Eidenmüller
authors.forename: Ingrid
authors.initials: I
authors.lastname: Wagner
authors.forename: Tatjana
authors.initials: T
authors.lastname: Achenbach
authors.forename: Thomas
authors.initials: T
authors.lastname: Aigner
authors.forename: Eckart
authors.initials: E
authors.lastname: Bartnik
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000201:enzymology / Q000378:metabolism*; D015536:Down-Regulation; D020869:Gene Expression Profiling; D006132:Growth Plate / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000009:adverse effects / Q000037:antagonists & inhibitors* / Q000502:physiology; D020930:MAP Kinase Kinase Kinases / Q000502:physiology; D020782:Matrix Metalloproteinases / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D010003:Osteoarthritis / Q000201:enzymology* / Q000209:etiology / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D000099151:MAP Kinase Kinase Kinase 7
chemical_list: D007375:Interleukin-1; D020930:MAP Kinase Kinase Kinases; D020782:Matrix Metalloproteinases; D014409:Tumor Necrosis Factor-alpha; D000099151:MAP Kinase Kinase Kinase 7