Articular cartilage proteoglycans from normal and osteoarthritic mice

Abstract

Articular cartilage proteoglycans from an osteoarthritic mouse strain, STR/IN, were labeled in vivo with 35S-sulfate and characterized with respect to extractability, ability to aggregate, size of monomer and glycosaminoglycan chains, sulfation of glycosaminoglycans, relative amounts of chondroitin-4 sulfate and chondroitind sulfate, and link proteins. The proportion of 35S-labeled proteoglycans extractable by 0.4M guanidine hydrochloride was the same in control and osteoarthritic animals. However, a greater proportion was extractable by 4M guanidine hydrochloride in the STRAN animals as compared with the control mice. The ability of the 35S-proteoglycans to aggregate was comparable in controls and osteoarthritic mice, as judged by their exclusion on Sepharose CL-2B. Monomers from both controls and osteoarthritic animals eluted from Sepharose CL-2B with a K A V of 0.47. Glycosaminoglycans from control and osteoarthritic animals eluted from Sepharose CL-6B with a K A v of 0.63, and do differences in sulfation or chondroitin-4 sulfate content were found. Aggregates were immunoprecipitated with link protein-specific antiserum, and only link protein 2

Regulation of nitric oxide and bcl‐2 expression by shear stress in human osteoarthritic chondrocytes in vitro

“…Excessive or inappropriate mechanical force imparted to articular cartilage has been implicated as a contributing factor in arthroses [Thompson and Bassett, 1970; Simon, 1978; Carter et al, 1987]. Mechanically induced joint degeneration involves alterations in proteoglycan content [Rostand et al, 1986; Säämänen et al, 1990], thinning and fibrillation of the articular surface [Lukoschek et al, 1988], an imbalance between proteases and protease inhibitors [Ehrlich et al, 1977; Ehrlich, 1985; Dean et al, 1989], and induction of pro‐inflammatory cytokines [Mohtai et al, 1996; Shinmei and Nemoto, 1996]. The results presented here show that shear stress dose‐dependently upregulated nitric oxide release and altered processes associated with apoptosis in human osteoarthritic chondrocytes.…”

A heparin‐binding growth factor, midkine, binds to a chondroitin sulfate proteoglycan, PG‐M/versican

“…Therefore, composition of PG‐M/versican from mouse embryos and that from chicken embryos may be similar. However, chondroitin sulfate proteoglycans from the mouse, such as PG‐H/aggrecan, are known to be rich in chondroitin 4‐sulfate, but contain chondroitin 6‐sulfate only in small amounts [48,49]. Oversulfated chondroitin sulfate structures have been found in mammals such as in mast cells and macrophages [50–53], but not in many sources.…”

The STR/ort mouse model of spontaneous osteoarthritis – an update

“…Subtle changes in STR/ort AC matrix composition, and in glycosaminoglycan PG content in particular, is observed in STR/ort male mice in comparison to age-matched CBA mice36, 43. Indeed, chondroitin sulphate content, predominantly C6S, is elevated in STR/ort mice at 8–19 weeks (before OA onset), decreases at 24–26 weeks of age, before increasing again thereafter (after OA onset) 36 .…”