title: The roles of canonical and non-canonical Wnt signaling in human de-differentiated articular chondrocytes.
abstract: Osteoarthritis is the most prevalent form of arthritis in the world and it is becoming a major public health problem. Osteoarthritic chondrocytes undergo morphological and biochemical changes that lead to de-differentiation. The involvement of signaling pathways, such as the Wnt pathway, during cartilage pathology has been reported. Wnt signaling regulates critical biological processes. Wnt signals are transduced through at least three intracellular signaling pathways including the canonical Wnt/β-catenin pathway, the Wnt/Ca2 + pathway and the Wnt/planar cell polarity pathway. We investigated the involvement of the Wnt canonical and non-canonical pathways in human articular chondrocyte de-differentiation in vitro. Human articular chondrocytes were cultured through four passages with no treatment, or with sFRP3 treatment, an inhibitor of Wnt pathways, or with DKK1 treatment, an inhibitor of the canonical pathway. Chondrocyte-secreted markers and Wnt pathway components were analyzed using western blotting and qPCR. Inhibition of the Wnt pathway showed that the canonical Wnt signaling probably is responsible for inhibition of collagen II expression, activation of metalloproteinase 13 expression and regulation of Wnt7a and c-jun expression during chondrocyte de-differentiation in vitro. Our results also suggest that expressions of eNOS, Wnt5a and cyclinE1 are regulated by non-canonical Wnt signaling.
authors.affiliation: Immuno-Rheumatology research laboratory, Rheumatology Department, La Rabta Hospital, University of Tunis-El Manar.
authors.forename: N
authors.initials: N
authors.lastname: Sassi
authors.forename: L
authors.initials: L
authors.lastname: Laadhar
authors.forename: M
authors.initials: M
authors.lastname: Allouche
authors.forename: B
authors.initials: B
authors.lastname: Zandieh-Doulabi
authors.forename: M
authors.initials: M
authors.lastname: Hamdoun
authors.forename: J
authors.initials: J
authors.lastname: Klein-Nulend
authors.forename: S
authors.initials: S
authors.lastname: Makni
authors.forename: S
authors.initials: S
authors.lastname: Sellami
mesh_terms: D015153:Blotting, Western; D002358:Cartilage, Articular / Q000166:cytology* / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D051153:Wnt Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D000094742:Secreted Frizzled-Related Proteins
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D051153:Wnt Proteins; C501126:DKK1 protein, human; C118723:SFRP4 protein, human; D000094742:Secreted Frizzled-Related Proteins