Stable Genetic Alterations of b- Catenin and ROR2 Regulate the Wnt Pathway, Affect the Fate of MSCs

The Wnt pathways have been shown to be critical for the fate of mesenchymal stem cells (MSCs) in vitro, but their roles in MSCs in vivo remain poorly characterized due to the lack of stable alterations in their signaling. In the present study, we constructed long-term and stable mMSCs lines with activated and inactivated -catenin (the key molecule of the canonical Wnt signaling pathway) or ROR2 (the key molecule of the noncanonical Wnt5a/ROR2 signaling pathway) modifications with lentiviral vectors. We found that the transduction efficiencies mediated by the lentiviral vectors were 92.61-97.04% and were maintained over 20 passages of mMSCs. Transfection by lentiviral vectors not only regulated the mRNA and protein expression of -catenin or ROR2 but also regulated nuclear -catenin accumulation or the Wnt5a/JNK and Wnt5a/PKC pathways belonging to the canonical Wnt and noncanonical Wnt5a/ROR2 pathways, respectively. -Catenin or ROR2 gene overexpression promoted mMSC proliferation, migration and differentiation into osteoblasts, while inhibiting the adipogenic differentiation of mMSCs. In contrast, inactivation of the -catenin or ROR2 genes resulted in the opposite effects. Therefore, these results confirm that lentiviral vector transduction can facilitate sustained and efficient gene modification of the Wnt pathway in mMSCs. This study provides a method to investigate the effects of the Wnt pathway on the fate of mMSCs in vivo and for the further improvement of MSC-based therapies. J. Cell. Physiol. 229: 791-800, 2014. (c) 2013 Wiley Periodicals, Inc.