title: Articular chondrocytes express the receptor for advanced glycation end products: Potential role in osteoarthritis.
abstract: OBJECTIVE
  The receptor for advanced glycation end products (RAGE) binds multiple ligands, including S100 proteins, high mobility group box chromosomal protein 1 (HMGB-1), and AGEs, all of which are present in articular cartilage. Stimulation of RAGE signaling can lead to MAP kinase activation and increased NF-kappaB activity. The objective of the present study was to determine if chondrocytes express functional RAGE.
  
  
  METHODS
  The presence of chondrocyte RAGE was analyzed by immunohistochemistry using normal and osteoarthritic (OA) cartilage from young and old monkeys and humans, immunoblotting of chondrocyte lysates and human cartilage extracts, and reverse transcription-polymerase chain reaction (RT-PCR) analysis of RNA from chondrocytes treated with interleukin-1 (IL-1) and fibronectin fragments. RAGE signaling was evaluated by stimulating chondrocytes with S100B and HMGB-1 and analyzing for activation of the ERK MAP kinase and NF-kappaB. The ability of S100B and HMGB-1 to stimulate matrix metalloproteinase 13 (MMP-13) production was also assessed. A pull-down assay using biotin-labeled S100B was used to demonstrate binding to RAGE.
  
  
  RESULTS
  RAGE was detected in sections of monkey knee cartilage and human knee and ankle cartilage. Increased immunostaining for RAGE was noted in cartilage from older adult monkeys and humans and was further increased in OA tissue. RAGE was also detected by immunoblotting and by RT-PCR, where IL-1beta and fibronectin fragments were found to stimulate RAGE expression. Stimulation of chondrocytes with S100B or HMGB-1 increased phosphorylation of the ERK MAP kinase and the p65 subunit of NF-kappaB and increased the production of MMP-13. This signaling was inhibited in cells pretreated with soluble RAGE, and S100B was shown to bind to chondrocyte RAGE.
  
  
  CONCLUSIONS
  Articular chondrocytes express functional RAGE. The increase in RAGE noted in OA cartilage and the ability of RAGE ligands to stimulate chondrocyte MAP kinase and NF-kappaB activity and to stimulate MMP-13 production suggests that chondrocyte RAGE signaling could play a role in OA.
authors.affiliation: Rush Medical College, Chicago, IL 60612, USA. rloeser@rush.edu
authors.forename: Richard F
authors.initials: RF
authors.lastname: Loeser
authors.forename: Raghunatha R
authors.initials: RR
authors.lastname: Yammani
authors.forename: Cathy S
authors.initials: CS
authors.lastname: Carlson
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
authors.forename: Ada
authors.initials: A
authors.lastname: Cole
authors.forename: Hee-Jeong
authors.initials: HJ
authors.lastname: Im
authors.forename: Laura S
authors.initials: LS
authors.lastname: Bursch
authors.forename: Shi Du
authors.initials: SD
authors.lastname: Yan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000378:metabolism; D002358:Cartilage, Articular / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D016022:Case-Control Studies; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism*; D017364:Collagenases / Q000096:biosynthesis; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005353:Fibronectins / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D053509:Matrix Metalloproteinase 13; D008875:Middle Aged; D016328:NF-kappa B / Q000378:metabolism; D009414:Nerve Growth Factors / Q000378:metabolism; D010003:Osteoarthritis / Q000503:physiopathology*; D010446:Peptide Fragments / Q000494:pharmacology; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000378:metabolism*; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D005353:Fibronectins; D007375:Interleukin-1; D016328:NF-kappa B; D009414:Nerve Growth Factors; D010446:Peptide Fragments; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; C579160:S100B protein, human; D048049:Extracellular Signal-Regulated MAP Kinases; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13