Open AccessMechanisms involved in enhancement of the expression and function of aggrecanases by hyaluronan oligosaccharides
Author(s) -
Ariyoshi Wataru,
Takahashi Nobunori,
Hida Daisuke,
Knudson Cheryl B.,
Knudson Warren
Publication year - 2012
Publication title -
arthritis & rheumatism
Language(s) - English
Resource type - Journals
eISSN - 1529-0131
pISSN - 0004-3591
DOI - 10.1002/art.33329
Subject(s) - adamts , aggrecan , aggrecanase , chemistry , microbiology and biotechnology , chondrocyte , matrix metalloproteinase , biochemistry , thrombospondin , biology , metalloproteinase , osteoarthritis , medicine , alternative medicine , pathology , in vitro , articular cartilage
Objective Small hyaluronan (HA) oligosaccharides serve as competitive receptor antagonists to displace HA from the cell surface and induce cell signaling events. In articular chondrocytes, this cell signaling is mediated by the HA receptor CD44 and induces stimulation of genes involved in matrix degradation, such as matrix metalloproteinases (MMPs) as well as matrix repair genes including type II collagen, aggrecan, and HA synthase 2. The objective of this study was to determine changes in the expression and function of aggrecanases after disruption of chondrocyte CD44–HA interactions. Methods Bovine articular chondrocytes or bovine cartilage tissue was pretreated with a variety of inhibitors of major signaling pathways prior to the addition of HA oligosaccharides. Changes in aggrecanase were monitored by real‐time reverse transcription–polymerase chain reaction and Western blot analyses of ADAMTS‐4, ADAMTS‐5, and aggrecan proteolytic fragments. To test the interactions between ADAMTS‐4 and membrane type 4 MMP (MT4‐MMP), protein lysates purified from stimulated chondrocytes were subjected to coimmunoprecipitation. Results Disruption of chondrocyte CD44–HA interactions with HA oligosaccharides induced the transcription of ADAMTS‐4 and ADAMTS‐5 in a time‐ and dose‐dependent manner. The association of glycosyl phosphatidylinositol–anchored MT4‐MMP with ADAMTS‐4 was also induced in articular chondrocytes by HA oligosaccharides. Inhibition of the NF‐κB pathway blocked HA oligosaccharide‐mediated stimulation of aggrecanases. Conclusion Disruptive changes in chondrocyte–matrix interactions by HA oligosaccharides induce matrix degradation and elevate aggrecanases via the activation of the NF‐κB signaling pathway.