title: IL-6 and its soluble receptor augment aggrecanase-mediated proteoglycan catabolism in articular cartilage.
abstract: Elevated concentrations of interleukin-6 (IL-6) and soluble IL-6 receptor (sIL-6R) in the synovial fluids and serum of patients with arthritis have been implicated in the joint tissue destruction associated with these conditions, however studies conducted to date on the role and effects of IL-6 in the process of cartilage proteoglycan (aggrecan) catabolism are disparate. In the present study, bovine articular cartilage explants were maintained in a model organ culture system in the presence or absence of IL-1alpha or TNF-alpha, and under co-stimulation with or without IL-6 and/or sIL-6R. After measuring proteoglycan loss from the explants, the proteolytic activity and expression profiles of aggrecanase(s) was assessed for each culture condition. Stimulation of cartilage explants with IL-6 and/or sIL-6R potentiated aggrecan catabolism and release above that seen in the presence of IL-1alpha or TNF-alpha alone. This catabolism was associated with aggrecanase (but not MMP) activity, with correlative mRNA expression for aggrecanase-2.
authors.affiliation: Connective Tissue Biology Research Group, Cardiff School of Biosciences, Cardiff University, Museum Avenue, CF10 3US, Cardiff, UK. flannerycr@cardiff.ac.uk
authors.forename: C R
authors.initials: CR
authors.lastname: Flannery
authors.forename: C B
authors.initials: CB
authors.lastname: Little
authors.forename: C E
authors.initials: CE
authors.lastname: Hughes
authors.forename: C L
authors.initials: CL
authors.lastname: Curtis
authors.forename: B
authors.initials: B
authors.lastname: Caterson
authors.forename: S A
authors.initials: SA
authors.lastname: Jones
mesh_terms: D051722:ADAM Proteins; D000071121:ADAMTS4 Protein; D053674:Aggrecans; D000818:Animals; D002358:Cartilage, Articular / Q000187:drug effects / Q000201:enzymology*; D002417:Cattle; D010450:Endopeptidases / Q000378:metabolism*; D016326:Extracellular Matrix Proteins; D015870:Gene Expression; D015850:Interleukin-6 / Q000494:pharmacology*; D037181:Lectins, C-Type; D008666:Metalloendopeptidases / Q000235:genetics / Q000378:metabolism; D009924:Organ Culture Techniques; D011348:Procollagen N-Endopeptidase; D011509:Proteoglycans / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D019947:Receptors, Interleukin-6 / Q000378:metabolism*
chemical_list: D053674:Aggrecans; D016326:Extracellular Matrix Proteins; D015850:Interleukin-6; D037181:Lectins, C-Type; D011509:Proteoglycans; D012333:RNA, Messenger; D019947:Receptors, Interleukin-6; D010450:Endopeptidases; D051722:ADAM Proteins; D008666:Metalloendopeptidases; D011348:Procollagen N-Endopeptidase; D000071121:ADAMTS4 Protein; C083641:aggrecanase