title: Pharmacoproteomic study of the effects of chondroitin and glucosamine sulfate on human articular chondrocytes.
abstract: BACKGROUND
  Chondroitin sulfate (CS) and glucosamine sulfate (GS) are symptomatic slow-acting drugs for osteoarthritis (OA) widely used in clinic. Despite their widespread use, knowledge of the specific molecular mechanisms of their action is limited. The aim of this work is to explore the utility of a pharmacoproteomic approach for the identification of specific molecules involved in the pharmacological effect of GS and CS.
  
  
  METHODS
  Chondrocytes obtained from three healthy donors were treated with GS 10 mM and/or CS 200 μg/mL, and then stimulated with interleukin-1β (IL-1β) 10 ng/mL. Whole cell proteins were isolated 24 hours later and resolved by two-dimensional electrophoresis. The gels were stained with SYPRORuby. Modulated proteins were identified by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF/TOF) mass spectrometry. Real-time PCR and Western blot analyses were performed to validate our results.
  
  
  RESULTS
  A total of 31 different proteins were altered by GS or/and CS treatment when compared to control. Regarding their predicted biological function, 35% of the proteins modulated by GS are involved in signal transduction pathways, 15% in redox and stress response, and 25% in protein synthesis and folding processes. Interestingly, CS affects mainly energy production (31%) and metabolic pathways (13%), decreasing the expression levels of ten proteins. The chaperone GRP78 was found to be remarkably increased by GS alone and in combination with CS, a fact that unveils a putative mechanism for the reported anti-inflammatory effect of GS in OA. On the other hand, the antioxidant enzyme superoxide dismutase 2 (SOD2) was significantly decreased by both drugs and synergistically by their combination, thus suggesting a drug-induced decrease of the oxidative stress caused by IL-1β in chondrocytes.
  
  
  CONCLUSIONS
  CS and GS differentially modulate the proteomic profile of human chondrocytes. This pharmacoproteomic approach unravels the complex intracellular mechanisms that are modulated by these drugs on IL1β-stimulated human articular chondrocytes.
authors.affiliation: Rheumatology Division, INIBIC-CHU A Coruña, As Xubias s/n, A Coruña 15006, Spain. valentina.calamia@sergas.es
authors.forename: Valentina
authors.initials: V
authors.lastname: Calamia
authors.forename: Cristina
authors.initials: C
authors.lastname: Ruiz-Romero
authors.forename: Beatriz
authors.initials: B
authors.lastname: Rocha
authors.forename: Patricia
authors.initials: P
authors.lastname: Fernández-Puente
authors.forename: Jesús
authors.initials: J
authors.lastname: Mateos
authors.forename: Eulàlia
authors.initials: E
authors.lastname: Montell
authors.forename: Josep
authors.initials: J
authors.lastname: Vergés
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Blanco
mesh_terms: D002356:Cartilage / Q000166:cytology / Q000276:immunology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology; D002809:Chondroitin Sulfates / Q000494:pharmacology*; D015180:Electrophoresis, Gel, Two-Dimensional; D000091342:Endoplasmic Reticulum Chaperone BiP; D005944:Glucosamine / Q000494:pharmacology*; D006801:Humans; D053583:Interleukin-1beta / Q000276:immunology / Q000494:pharmacology; D007719:Knee Joint / Q000166:cytology / Q000276:immunology; D020370:Osteoarthritis, Knee / Q000188:drug therapy* / Q000276:immunology; D040901:Proteomics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000099156:Superoxide Dismutase 2
chemical_list: D002809:Chondroitin Sulfates; D000091342:Endoplasmic Reticulum Chaperone BiP; D005944:Glucosamine; D053583:Interleukin-1beta; D013482:Superoxide Dismutase; D000099156:Superoxide Dismutase 2; C000717247:HSPA5 protein, human