Keratan sulfate suppresses cartilage damage and ameliorates inflammation in an experimental mice arthritis model

https://doi.org/10.1016/j.bbrc.2010.09.082Get rights and content

Abstract

Proteoglycans bearing keratan sulfate (KS), such as aggrecan, are components of the human cartilage extracellular matrix (ECM). However, the role of KS in influencing cartilage degradation associated with arthritis remains to be completely understood. KS side chains of the length found in human cartilage are not found in murine skeletal tissues. Using a murine model of inflammatory polyarthritis and cartilage explants exposed to interleukin-1α (IL-1α), we examined whether administering KS could influence intraarticular inflammation and cartilage degradation. Acute arthritis was induced by intravenous administration of an anti-type II collagen antibody cocktail, followed by an intraperitoneal injection of lipopolysaccharide. This treatment was followed by an intraperitoneal KS administration in half of the total mice to evaluate the therapeutic potential of KS for ameliorating arthritis. To investigate the therapeutic potential ex vivo, we examined cartilage fragility by measuring IL-1α-induced aggrecan release from cartilage explants treated with or without KS. Intraperitoneal KS administration ameliorated arthritis in DBA/1J mice. The aggrecan release induced by IL-1α was less in cartilage explants containing media with KS than in those without KS. Our data indicate that exogenous KS ameliorated arthritis in vivo and suppressed cartilage degradation ex vivo. KS may have important therapeutic potential in the treatment of inflammatory arthritis. The mechanism responsible for this requires further investigation, but KS may become a novel therapeutic agent for treating inflammatory diseases such as rheumatoid arthritis.

Research highlights

► Intraperitoneal administration of keratan sulfate (KS) reduced the intraarticular inflammation and cartilage degradation in mice induced by anti-type II collagen antibody cocktail, an animal model of human arthritis. ► The presence of KS in culture of murine cartilage explants suppressed IL-1-induced aggrecan degradation. ► KS may have important therapeutic potential in the treatment of inflammatory arthritis.

Introduction

Rheumatoid arthritis (RA) is a major musculoskeletal disorder involving joint destruction of articular cartilage and subchondral bone resulting in a negative impact on the quality of life [1]. Articular cartilage is composed of chondrocytes embedded in an extracellular matrix (ECM), which provides the biomechanical factors essential for articular movement, especially those for resisting compressive forces. The two major components of cartilage ECM are type II collagen and proteoglycans. A predominant component of the latter is aggrecan, which is further composed of two types of glycosaminoglycan (GAG) side chains in humans, namely chondroitin sulfate (CS) and keratan sulfate (KS). GAGs contain sulfate residues and are thus negatively charged. This negative charge facilitates water retention in ECM, enabling the cartilage to resist compressive forces.

CS combined with glucosamine salts provides symptomatic relief and chondroprotection [2], [3], [4]. However, whether KS has similar properties during articular cartilage degradation remains unclear. The role of KS side chains in articular cartilage degradation remains to be understood with regard to arthritis [5].

In general, KS side chains of the type found in human cartilage and other mammals are not found in the skeletal tissues of mice and rats [6]. However, human articular cartilage has smaller amounts of KS than CS, and higher rates of KS/CS changes occur in older individuals [7], [8]. Thus, we hypothesized that KS affect changes in articular cartilage characteristics of arthritis and may be chondroprotective in humans based on their longevity compared to rats and mice.

Murine anti-type II collagen antibody-induced arthritis and cartilage organ culture are widely used to study the mechanisms of cartilage degradation associated with inflammatory joint diseases such as RA [9], [10]. In this study, we employed these arthritis models to verify the role of KS in cartilage degradation in arthritis.

Molecular fragments of cartilage are antigenic and can stimulate an arthritic response [11], [12], [13], [14]. Thus, lesser the cartilage breaks down and releases fragments into synovial fluid, lesser is the severity of arthritis in the joint. Based on this, if KS has chondroprotective ability in vitro, this ability may lead to suppressive effects of arthritis in vivo.

Section snippets

Mice

DBA/1J mice, aged 6–7 weeks, were purchased from Japan SLC, Shizuoka, Japan. They were maintained with sterilized food, water, and bedding at the Animal Facility of Nagoya University School of Medicine. All experiments were approved by the Animal Ethics Committee of Nagoya University.

Mouse arthritis models

Arthritis was induced in 20 mice to examine arthritis scores. On day 0, each mouse received intravenous tail vein injection of 2 mg in 200 μ arthritogenic monoclonal antibody cocktail (Iwai Chemicals, Tokyo, Japan)

Suppression of antibody-induced arthritis in DBA/1J mice by KS administration

First, we examined and assessed the effect of exogenous KS on arthritis in DBA/1J mice. Arthritis was induced by intravenous administration of an anti-type II collagen antibody cocktail and subsequently injecting lipopolysaccharide intraperitoneally. These agents were supplemented with 40 μg of intraperitoneal KS in PBS administered daily to evaluate the therapeutic potential of KS.

Arthritis scores increased in a time-dependent manner in mice treated with and without KS after antibody

Discussion

The results of our study demonstrate that KS administration ameliorated arthritis in vivo, and that KS inhibited aggrecan release from cartilage in vitro. Molecular fragments of cartilage are antigenic and can stimulate an arthritic response [11], [12], [13], [14]. Thus, if KS has chondroprotective ability in vitro, this can lead to the suppression of arthritis in vivo. The results of our study collectively suggest that KS plays a suppressive role in arthritis in terms of chondroprotection.

The

Conclusions

Our results collectively suggest that KS plays an important role in suppressing cartilage degradation associated with inflammatory joint diseases, resulting in a suppression of inflammation. Low molecular weight CS suppresses type II collagen-induced arthritis in DBA/1J mice [39], and its oral administration is clinically useful for OA and RA therapy. Phosphate prodrugs derived from N-acetylglucosamine have chondroprotective ability in bovine articular cartilage cultures in vitro [40]. Our

Acknowledgments

This work was supported in part by the 21st Century COE program and Global COE program, MEXT, Japan. The authors wish to thank A. Robin Poole for his comments on this study.

References (40)

  • G. Venn et al.

    Absence of keratan sulphate from skeletal tissues of mouse and rat

    Biochem. J.

    (1985)
  • R. Mallinger et al.

    Histochemistry of the extracellular matrix of aging hyaline cartilage

    Folia Histochem. Cytobiol.

    (1987)
  • M.F. Venn

    Variation of chemical composition with age in human femoral head cartilage

    Ann. Rheum. Dis.

    (1978)
  • D.L. Asquith et al.

    Animal models of rheumatoid arthritis

    Eur. J. Immunol.

    (2009)
  • M.K. Majumdar et al.

    Double-knockout of ADAMTS-4 and ADAMTS-5 in mice results in physiologically normal animals and prevents the progression of osteoarthritis

    Arthritis Rheum.

    (2007)
  • P. Ghosh et al.

    Arthritic disease suppression and cartilage protection with glycosaminoglycan polypeptide complexes (Peptacans) derived from the cartilage extracellular matrix: a novel approach to therapy

    Inflammopharmacology

    (2006)
  • J.Y. Leroux et al.

    Immunity to the G1 globular domain of the cartilage proteoglycan aggrecan can induce inflammatory erosive polyarthritis and spondylitis in BALB/c mice but immunity to G1 is inhibited by covalently bound keratan sulfate in vitro and in vivo

    J. Clin. Invest.

    (1996)
  • U. Boiers et al.

    Collagen type II is recognized by a pathogenic antibody through germline encoded structures

    Eur. J. Immunol.

    (2008)
  • H. Stanton et al.

    The 45 kDa collagen-binding fragment of fibronectin induces matrix metalloproteinase-13 synthesis by chondrocytes and aggrecan degradation by aggrecanases

    Biochem. J.

    (2002)
  • K. Terato et al.

    Collagen-induced arthritis in mice: synergistic effect of E. coli lipopolysaccharide bypasses epitope specificity in the induction of arthritis with monoclonal antibodies to type II collagen

    Autoimmunity

    (1995)
  • Cited by (0)

    View full text