title: Histone deacetylase inhibitors modulate metalloproteinase gene expression in chondrocytes and block cartilage resorption.
abstract: Cartilage destruction in the arthritides is thought to be mediated by two main enzyme families: the matrix metalloproteinases (MMPs) are responsible for cartilage collagen breakdown, and enzymes from the ADAMTS (a disintegrin and metalloproteinase domain with thrombospondin motifs) family mediate cartilage aggrecan loss. Many genes subject to transcriptional control are regulated, at least in part, by modifications to chromatin, including acetylation of histones. The aim of this study was to examine the impact of histone deacetylase (HDAC) inhibitors on the expression of metalloproteinase genes in chondrocytes and to explore the potential of these inhibitors as chondroprotective agents. The effects of HDAC inhibitors on cartilage degradation were assessed using a bovine nasal cartilage explant assay. The expression and activity of metalloproteinases was measured using real-time RT-PCR, western blot, gelatin zymography, and collagenase activity assays using both SW1353 chondrosarcoma cells and primary human chondrocytes. The HDAC inhibitors trichostatin A and sodium butyrate potently inhibit cartilage degradation in an explant assay. These compounds decrease the level of collagenolytic enzymes in explant-conditioned culture medium and also the activation of these enzymes. In cell culture, these effects are explained by the ability of HDAC inhibitors to block the induction of key MMPs (e.g. MMP-1 and MMP-13) by proinflammatory cytokines at both the mRNA and protein levels. The induction of aggrecan-degrading enzymes (e.g. ADAMTS4, ADAMTS5, and ADAMTS9) is also inhibited at the mRNA level. HDAC inhibitors may therefore be novel chondroprotective therapeutic agents in arthritis by virtue of their ability to inhibit the expression of destructive metalloproteinases by chondrocytes.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich, UK. d.a.young@ncl.ac.uk
authors.forename: David A
authors.initials: DA
authors.lastname: Young
authors.forename: Rachel L
authors.initials: RL
authors.lastname: Lakey
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Pennington
authors.forename: Debra
authors.initials: D
authors.lastname: Jones
authors.forename: Lara
authors.initials: L
authors.lastname: Kevorkian
authors.forename: Dylan R
authors.initials: DR
authors.lastname: Edwards
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Cawston
authors.forename: Ian M
authors.initials: IM
authors.lastname: Clark
mesh_terms: D000818:Animals; D001862:Bone Resorption / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics; D002358:Cartilage, Articular / Q000187:drug effects / Q000201:enzymology*; D002417:Cattle; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects* / Q000502:physiology; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D045726:Metalloproteases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D014407:Tumor Cells, Cultured
chemical_list: D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D045726:Metalloproteases; D006655:Histone Deacetylases