Enhanced expression of the human chitinase 3-like 2 gene (YKL-39) but not chitinase 3-like 1 gene (YKL-40) in osteoarthritic cartilage

https://doi.org/10.1016/S0006-291X(02)02585-8Get rights and content

Abstract

The knowledge of molecular alterations in osteoarthritic cartilage is important to identify novel therapeutic targets or to develop new diagnostic tools. We aimed to characterize the molecular response to cartilage degeneration by identification of differentially expressed genes in human osteoarthritic versus normal cartilage. Gene fragments selectively amplified in osteoarthritic cartilage by cDNA representational difference analysis included YKL-39 and the oesophageal-cancer-related-gene-4 (ECRG4). YKL-39 expression was significantly upregulated in cartilage from patients with osteoarthritis (n=14) versus normal subjects (n=8) according to real-time PCR (19-fold, p=0.009) and cDNA array analysis (mean 15-fold, p<0.001) and correlated with collagen 2 up-regulation. In contrast, the homologous cousin molecule YKL-40 (chitinase 3-like 1), which is elevated in serum and synovial fluid of patients with arthritis, showed no significant regulation in OA cartilage. Enhanced levels of YKL-40 may, therefore, be derived from synovial cells while modulation of YKL-39 and collagen 2 expression reflected the cartilage metabolism in response to degradation.

Section snippets

Human samples

Osteoarthritic cartilage tissue was obtained after written consent from patients undergoing total knee or hip arthroplasty. Cartilage tissue with macroscopic evidence of degeneration was collected from the tibial plateau and classified as OA cartilage. Normal cartilage was obtained after written consent of the relatives or patients from two crime victims and patients undergoing amputation for tumor resection. The study was approved by the Local Ethics Committee.

RNA extraction

Cartilage poly(A)+-mRNA was

ECRG4 and YKL-39 gene fragments selectively amplified in OA cartilage

OA-specific gene expression was analyzed by RDA with osteoarthritic cartilage serving as tester and normal cartilage as driver. The reverse experiment (tester: normal, driver: OA) was designed as internal control. While a smear of cDNA products was evident in the starting material of both cartilage samples, a distinct band pattern of the final difference products appeared for the OA- and the normal-specific amplification after two cycles of RDA with different tester:driver ratios (Fig. 1).

Discussion

By analysis of gene expression in OA versus normal cartilage we have identified a strong and significant upregulation of YKL-39 and collagen 2 in OA and describe abundant expression of an unknown gene ECRG4 in cartilage independent of an OA status. Expression of YKL-39 and YKL-40, two mammalian members of the chitinase 3-like gene family lacking chitinase activity, has, to our knowledge, never been compared in OA versus normal cartilage. In this study, three different methodological approaches

Acknowledgements

The authors thank Regina Hess and Stephanie Kadel for excellent technical assistance and Sven Schneider for statistical support. This work was supported by a grant of the research fund of the Stiftung Orthopädische Universitätsklinik Heidelberg.

References (34)

  • J.S Johansen et al.

    Serum YKL-40: a new potential marker of prognosis and location of metastases of patients with recurrent breast cancer

    Eur. J. Cancer

    (1995)
  • R.B Kirkpatrick et al.

    Induction and expression of human cartilage glycoprotein 39 in rheumatoid inflammatory and peripheral blood monocyte-derived macrophages

    Exp. Cell Res.

    (1997)
  • J.R Connor et al.

    Human cartilage glycoprotein 39 (HC gp-39) mRNA expression in adult and fetal chondrocytes, osteoblasts and osteocytes by in situ hybridization

    Osteoarthritis Cartilage

    (2000)
  • J.A Buckwalter et al.

    Articular cartilage. Part II: Degeneration and osteoarthrosis, repair, regeneration, and transplantation

    J. Bone Joint. Surg. Am.

    (1997)
  • G Cs-Szabo et al.

    Changes in messenger RNA and protein levels of proteoglycans and link protein in human osteoarthritic cartilage samples

    Arthritis Rheum.

    (1997)
  • S Chubinskaya et al.

    Expression of matrix metalloproteinases in normal and damaged articular cartilage from human knee and ankle joints

    Lab. Invest.

    (1999)
  • T Aigner et al.

    Suppression of cartilage matrix gene expression in upper zone chondrocytes of osteoarthritic cartilage

    Arthritis Rheum.

    (1997)
  • Cited by (66)

    • Distinct degenerative phenotype of articular cartilage from knees with meniscus tear compared to knees with osteoarthritis

      2019, Osteoarthritis and Cartilage
      Citation Excerpt :

      CHI3L2 activates phosphorylation of extracellular signal regulated kinases ERK1/ERK2 in HEK293 and U87 malignant glioma (MG) cell lines33. YKL-39 mRNA has been shown to be significantly up-regulated in the cartilage of patients with OA34. Moreover, the level of YKL-39 mRNA expression was positively correlated with collagen type II up-regulation in both early and late stages of the disease35.

    • Chitinases and immunity: Ancestral molecules with new functions

      2015, Immunobiology
      Citation Excerpt :

      Strikingly, the chitinase activity of CHI3L2 was recovered by reverting two non-conservative substitutions in the active site to those found in the active enzymes, suggesting that CHI3L2 is a pseudo-chitinase with retention of chitinase-like ligand-binding properties (Knorr et al., 2003). CHI3L2 was originally isolated from the cultured medium of primary human articular cartilage chondrocytes (Steck et al., 2002). Comparison of the expression of CHI3L2 and CHI3L1 in osteoarthritic cartilage revealed, that CHI3L2 mRNA is significantly up-regulated in cartilage of patients with osteoarthritis (OA) versus normal subjects, while no significant up-regulation was detected for CHI3L1 mRNA in OA cartilage (De Ceuninck et al., 2005).

    View all citing articles on Scopus
    View full text