title: The regulation of aggrecanase ADAMTS-4 expression in human Achilles tendon and tendon-derived cells.
abstract: Several members of the ADAMTS (A Disintegrin And Metalloproteinase with ThromboSpondin motifs) family have been identified as aggrecanases, whose substrates include versican, the principal large proteoglycan in the tendon extracellular matrix. We have characterized the expression of ADAMTS-4 in human Achilles tendon and tendon-derived cells. ADAMTS-4 mRNA levels were higher in ruptured tendon compared with normal tendon or chronic painful tendinopathy. In tissue extracts probed by Western blotting, mature ADAMTS-4 (68 kDa) was detected only in ruptured tendons, while processed ADAMTS-4 (53 kDa) was detected also in chronic painful tendinopathy and in normal tendon. In cultured Achilles tendon cells, transforming growth factor-beta (TGF-beta) stimulated ADAMTS-4 mRNA expression (typically 20-fold after 24 h), while interleukin-1 induced a smaller, shorter-term stimulation which synergised markedly with that induced by TGF-beta. Increased levels of immunoreactive proteins consistent with mature and processed forms of ADAMTS-4 were detected in TGF-beta-stimulated cells. ADAMTS-4 mRNA was expressed at higher levels by tendon cells in collagen gels than in monolayer cultures. In contrast, the expression of ADAMTS-1 and -5 mRNA was lower in collagen gels compared with monolayers, and these mRNA showed smaller or opposite responses to growth factors and cytokines compared with that of ADAMTS-4 mRNA. We conclude that both ADAMTS-4 mRNA and ADAMTS-4 protein processing may be differentially regulated in normal and damaged tendons and that both the matrix environment and growth factors such as TGF-beta are potentially important factors controlling ADAMTS aggrecanase activities in tendon pathology.
authors.affiliation: Rheumatology Research Unit, Addenbrooke's Hospital, Cambridge, UK.
authors.forename: Anthony N
authors.initials: AN
authors.lastname: Corps
authors.forename: Gavin C
authors.initials: GC
authors.lastname: Jones
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Harrall
authors.forename: Valerie A
authors.initials: VA
authors.lastname: Curry
authors.forename: Brian L
authors.initials: BL
authors.lastname: Hazleman
authors.forename: Graham P
authors.initials: GP
authors.lastname: Riley
mesh_terms: D051722:ADAM Proteins / Q000235:genetics* / Q000378:metabolism; D000071097:ADAMTS1 Protein; D000071121:ADAMTS4 Protein; D000071116:ADAMTS5 Protein; D000125:Achilles Tendon / Q000166:cytology / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015153:Blotting, Western; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002478:Cells, Cultured; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D053583:Interleukin-1beta / Q000494:pharmacology; D008875:Middle Aged; D011348:Procollagen N-Endopeptidase / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013708:Tendon Injuries / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
chemical_list: D019485:Bone Morphogenetic Proteins; D036341:Intercellular Signaling Peptides and Proteins; D053583:Interleukin-1beta; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D000071097:ADAMTS1 Protein; C103859:ADAMTS1 protein, human; D000071116:ADAMTS5 Protein; C121532:ADAMTS5 protein, human; D011348:Procollagen N-Endopeptidase; D000071121:ADAMTS4 Protein; C000603918:ADAMTS4 protein, human