Increased damage to type II collagen in osteoarthritic articular cartilage detected by a new immunoassay.

Abstract

A new immunoassay was developed to detect denaturation of type II collagen in osteoarthritis (OA). A peptide, al(II)-CBllB, located in the CB11 peptide of type II collagen, was synthesized and used to produce a monoclonal antibody (COL2-3/4m) of the IgG,(K) isotype. This reacts with a defined epitope in denatured but not native type II collagen and the a3 chain of type XI collagen. The latter is present in very small amounts (about 1% wt/wt) in cartilage relative to the al (II) chain. By using an enzyme-linked immunosorbent assay, type II collagen denaturation and total type II collagen content were determined. The epitope recognized by the antibody was resistant to cleavage by a-chymotrypsin and proteinase K which were used to extract al (II)-CB11B from the denatured (a-chymotrypsin soluble) and residual native (proteinase K soluble) collagen a-chains, respectively, present in human femoral articular cartilage. Type II collagen content was significantly reduced from a mean (range) of 14% (9.2-20.8%) of wet weight in 8 normal cartilages to 10.3% (7.4-15.0%) in 16 OA cartilages. This decrease, which may result in part from an increased hydration, was accompanied by an increase in the percent denaturation of type II collagen in OA to 6.0% of total type II collagen compared with 1.1% in normal tissue. The percent denaturation was ordinarily greater in the more superficial zone than in the deep zone of OA cartilage. (J. Clin. Invest.

The release of crosslinked peptides from type II collagen into human synovial fluid is increased soon after joint injury and in osteoarthritis

“…This strongly suggests that the activation of potential proteolytic degradation pathways of CII after a joint injury occurs as rapidly as that for aggrecan and other cartilage matrix components. This observation corroborates and extends recent studies by other techniques that have provided evidence for early damage to the cartilage collagen network after joint injury and in OA (26,(32)(33)(34)(35)51).…”

Restoration of the extracellular matrix in human osteoarthritic articular cartilage by overexpression of the transcription factor SOX9

“…In OA cartilage, the content increased 1.72-fold (P Ͻ 0.001) with 20 l of vector and 1.95-fold (P Ͻ 0.001) with 50 l (a 1.32-fold dose-dependent increase; P Ͻ 0.001). OA cartilage always contained less type II collagen than did normal cartilage, as has been described previously (40,41). Most notably, the content was significantly higher in treated OA cartilage than in control normal cartilage (1.48-fold [P Ͻ 0.001] with 20 l and 1.71-fold [P Ͻ 0.001] with 50 l of vector), probably due to restored SOX9 expression levels (see Figure 3).…”

Matrix metalloproteinase activities and their relationship with collagen remodelling in tendon pathology

“…Previous work has shown that the removal of proteoglycans and newly synthesised collagen with 4 M guanidine chloride does not irreversibly denature undamaged collagen, and 90% of the denatured collagen is retained within the cross-linked mature collagen fibrils (Hollander et al, 1994(Hollander et al, , 1995Bank et al, 1997). The mean proportion of denatured collagen in the control supraspinatus was 9.9% (range 2.6-16.7%) and did not change significantly across the age range from 18 to 96 years (Fig.…”