title: Catabolism of aggrecan proteoglycan aggregate components in short-term explant cultures of tendon.
abstract: Hyaluronan (HA) and link protein are essential components of the aggrecan proteoglycan aggregate, whereby HA binds multiple aggrecan monomers, an interaction which is stabilised by link protein. In this study, we have examined the turnover of the aggregate components, HA, link protein, and the N-terminal G1 domain of aggrecan, in explant cultures of tissue from compressed and tensional regions of young and mature bovine tendons. Western blot analyses revealed the release of highly processed link protein and G1-containing metabolites, in the absence of catabolic agents, indicating an increased turnover of these components in tendon. In addition, significant levels of HA were released from the tissue matrix into the media compartment. Furthermore, RT-PCR analysis showed that the mRNA expression of link protein and enzymes/proteins associated with HA metabolism may be modulated in the distinct functional regions of tendon with development. Perturbation of normal aggrecan aggregate metabolism may lead to tissue dysfunction.
authors.affiliation: Connective Tissue Biology Laboratories, Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff, CF10 3US, UK. s.g.rees@swansea.ac.uk
authors.forename: Sarah G
authors.initials: SG
authors.lastname: Rees
authors.forename: Clare L
authors.initials: CL
authors.lastname: Curtis
authors.forename: Colin M
authors.initials: CM
authors.lastname: Dent
authors.forename: Bruce
authors.initials: B
authors.lastname: Caterson
mesh_terms: D053674:Aggrecans; D000375:Aging / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D014453:Glucuronosyltransferase / Q000235:genetics; D018960:Hyaluronan Receptors / Q000235:genetics; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000378:metabolism*; D006821:Hyaluronoglucosaminidase / Q000235:genetics; D037181:Lectins, C-Type; D017434:Protein Structure, Tertiary; D011509:Proteoglycans / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013710:Tendons / Q000378:metabolism*; D013997:Time Factors; D046509:Tissue Culture Techniques; D000099249:Proteoglycan Link Protein
chemical_list: D053674:Aggrecans; D016326:Extracellular Matrix Proteins; D014453:Glucuronosyltransferase; D018960:Hyaluronan Receptors; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid; D006821:Hyaluronoglucosaminidase; D037181:Lectins, C-Type; D011509:Proteoglycans; D012333:RNA, Messenger; D000099249:Proteoglycan Link Protein