title: Enhanced expression of the human chitinase 3-like 2 gene (YKL-39) but not chitinase 3-like 1 gene (YKL-40) in osteoarthritic cartilage.
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.
authors.affiliation: Department of Orthopaedic Surgery, University of Heidelberg, Schlierbacher Landstrasse 200a, 69118, Heidelberg, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Steck
authors.forename: Stephen
authors.initials: S
authors.lastname: Breit
authors.forename: Steffen J
authors.initials: SJ
authors.lastname: Breusch
authors.forename: Matthias
authors.initials: M
authors.lastname: Axt
authors.forename: Wiltrud
authors.initials: W
authors.lastname: Richter
mesh_terms: D054392:Adipokines; D015152:Blotting, Northern; D002356:Cartilage / Q000378:metabolism*; D000071451:Chitinase-3-Like Protein 1; D024043:Collagen Type II / Q000096:biosynthesis; D018076:DNA, Complementary / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D037102:Lectins; D020411:Oligonucleotide Array Sequence Analysis; D010003:Osteoarthritis / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D054392:Adipokines; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D024043:Collagen Type II; D018076:DNA, Complementary; D006023:Glycoproteins; D037102:Lectins