title: Curcumin mediated suppression of nuclear factor-κB promotes chondrogenic differentiation of mesenchymal stem cells in a high-density co-culture microenvironment.
abstract: BACKGROUND
  Osteoarthritis (OA) and rheumatoid arthritis (RA) are characterised by joint inflammation and cartilage degradation. Although mesenchymal stem cell (MSC)-like progenitors are resident in the superficial zone of articular cartilage, damaged tissue does not possess the capacity for regeneration. The high levels of pro-inflammatory cytokines present in OA/RA joints may impede the chondrogenic differentiation of these progenitors. Interleukin (IL)-1β activates the transcription factor nuclear factor-κB (NF-κB), which in turn activates proteins involved in matrix degradation, inflammation and apoptosis. Curcumin is a phytochemical capable of inhibiting IL-1β-induced activation of NF-κB and expression of apoptotic and pro-inflammatory genes in chondrocytes. Therefore, the aim of the present study was to evaluate the influence of curcumin on IL-1β-induced NF-κB signalling pathway in MSCs during chondrogenic differentiation.
  
  
  METHODS
  MSCs were either cultured in a ratio of 1:1 with primary chondrocytes in high-density culture or cultured alone in monolayer with/without curcumin and/or IL-1β.
  
  
  RESULTS
  We demonstrate that although curcumin alone does not have chondrogenic effects on MSCs, it inhibits IL-1β-induced activation of NF-κB, activation of caspase-3 and cyclooxygenase-2 in MSCs time and concentration dependently, as it does in chondrocytes. In IL-1β stimulated co-cultures, four-hour pre-treatment with curcumin significantly enhanced the production of collagen type II, cartilage specific proteoglycans (CSPGs), β1-integrin, as well as activating MAPKinase signaling and suppressing caspase-3 and cyclooxygenase-2.
  
  
  CONCLUSIONS
  Curcumin treatment may help establish a microenvironment in which the effects of pro-inflammatory cytokines are antagonized, thus facilitating chondrogenesis of MSC-like progenitor cells in vivo. This strategy may support the regeneration of articular cartilage.
authors.affiliation: Institute of Anatomy, Ludwig-Maximilians-University Munich, Pettenkoferstrasse 11, D-80336 Munich, Germany. constanze.buhrmann@med.uni-muenchen.de
authors.forename: Constanze
authors.initials: C
authors.lastname: Buhrmann
authors.forename: Ali
authors.initials: A
authors.lastname: Mobasheri
authors.forename: Ulrike
authors.initials: U
authors.lastname: Matis
authors.forename: Mehdi
authors.initials: M
authors.lastname: Shakibaei
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002356:Cartilage / Q000166:cytology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism*; D020219:Chondrogenesis / Q000187:drug effects / Q000502:physiology; D018920:Coculture Techniques; D003474:Curcumin / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D053583:Interleukin-1beta / Q000378:metabolism / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D053583:Interleukin-1beta; D016328:NF-kappa B; D003474:Curcumin