Type II collagen levels correlate with mineralization by articular cartilage vesicles. Arthritis Rheum 2009 Sep;60(9):2741-6
Date
08/29/2009Pubmed ID
19714645Pubmed Central ID
PMC2749926DOI
10.1002/art.24773Scopus ID
2-s2.0-69449107152 (requires institutional sign-in at Scopus site) 16 CitationsAbstract
OBJECTIVE: Pathologic mineralization is common in osteoarthritic (OA) cartilage and may be mediated by extracellular organelles known as articular cartilage vesicles (ACVs). Paradoxically, ACVs isolated from OA human cartilage mineralize poorly in vitro compared with those isolated from normal porcine cartilage. We recently showed that collagens regulate ACV mineralization. We sought to determine differences between collagens and collagen receptors on human and porcine ACVs as a potential explanation of their different mineralization behaviors.
METHODS: ACVs were enzymatically released from old and young human and porcine hyaline articular cartilage. Western blotting was used to determine the presence of types I, II, VI, and X collagen and various collagen receptors on ACVs. Type II collagen was quantified by enzyme-linked immunosorbent assay. Biomineralization was assessed by measuring the uptake of (45)Ca by isolated ACVs in agarose gels and by ACVs in situ in freeze-thawed cartilage.
RESULTS: As previously shown, isolated human ACVs mineralized poorly in response to ATP compared with porcine ACVs, but human and porcine ACVs mineralized similarly in situ in freeze-thawed cartilage. Type II collagen levels were 100-fold higher in isolated human ACVs than in porcine ACVs. Type II collagen in human ACVs was of high molecular weight. Transglutaminase-crosslinked type II collagen showed increased resistance to collagenase, suggesting a possible explanation for residual collagen on human ACVs. Expression of other collagens and collagen receptors was similar on human and porcine ACVs.
CONCLUSION: Higher levels of type II collagen in human ACV preparations, perhaps mediated by increased transglutaminase crosslinking, may contribute to the decreased mineralization observed in isolated human ACVs in vitro.
Author List
Jubeck B, Muth E, Gohr CM, Rosenthal AKAuthor
Ann K. Rosenthal MD Associate Dean, Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdolescentAdult
Aged
Aged, 80 and over
Animals
Calcium Phosphates
Calcium Pyrophosphate
Cartilage, Articular
Collagen Type II
Humans
Organelles
Osteoarthritis
Receptors, Collagen
Swine
Transglutaminases
Young Adult
