Issue title: Selected Papers from the 5th China–France International Symposium “Stem Cells: From Bench to Bedside”, 12–14 December 2013, Kunming, China
Article type: Research Article
Authors: Hu, Yong; | Liu, Yang; | Lajeunesse, Daniel | Mainard, Didier; | Jouzeau, Jean-Yves; | Reboul, Pascal;
Affiliations: UMR 7365, CNRS-Université de Lorraine, IMoPA, Vandœuvre-lés-Nancy, France | Unité de Recherche en Arthrose, Centre de Recherche de l'Université de Montréal (CR-CHUM), Montréal, QC, Canada | Centre Hospitalier Universitaire, Nancy, France
Note: [] These authors have contributed equally.
Note: [] Address for correspondence: Pascal Reboul, Biopôle de l'Université de Lorraine, Campus Biologie-Santé, Faculté de Médecine, Room 2G66, 9 avenue de la forêt de Haye, CS50184, 54505 Vandœuvre-lés-Nancy Cedex, France. E-mail: [email protected]
Abstract: INTRODUCTION: Few studies have tried to discriminate a differential behavior between osteoarthritic (OA) osteoblasts (Obs). Based on osteocalcin level, we aimed, in the present study, to evaluate the capacity of OA Obs for producing molecules of the Wnt/β-catenin signaling pathway. METHODS: Human primary OA Obs (n=11) were exposed or not to 50 nM of 1,25 dihydroxyvitamin D3 (VitD3) for 24 h. Osteocalcin (OCN), TGF-β1, Dickkopf-related protein 2 (DKK2), R-spondin 2 (Rspo2), Wnt5b, and low density lipoprotein related-receptor 1 (LRP1) were evaluated by real time RT-PCR. RESULTS: All samples responded to VitD3 as validated by the increase in OCN expression. However two populations of Obs were discriminated; one called “high responders” whose OCN stimulation was higher than 100 fold (mean 881 fold, p<0.01, n=5) and the second one whose stimulation was inferior to 100 fold (mean 47 fold, p<0.01, n=6), namely “low responders”. In fact, high responders have a weaker basal expression of OCN. With regards to these two cell populations and in absence of VitD3 challenge, the expression level of TGF-β1 (15 fold, p<0.001), DKK2 (2.5 fold, p<0.002) and Wnt5b (5.5 fold, p<0.003) was higher in “high responders”, meanwhile Rspo2 and LRP1 expression was unchanged. VitD3 exacerbated this pattern but corrected OCN expression and favored Wnt agonist expression. CONCLUSION: We identified 2 populations of OA Obs according to the OCN expression under the control of VitD3. In addition under basal conditions, these 2 populations expressed differently TGF-β1, Wnt5b, DKK2, suggesting a heterogeneous differentiation and phenotype in Obs among OA patients.
Keywords: Osteoarthritis, osteoblast, Wnt system, vitamin D_3, osteocalcin
DOI: 10.3233/BME-141230
Journal: Bio-Medical Materials and Engineering, vol. 25, no. s1, pp. 103-110, 2015
