Osteogenic differentiation of Wharton's jelly-derived mesenchymal stem cells cultured on WJ-scaffold through conventional signalling mechanism

Wharton's jelly-derived extracellular matrix (WJ-ECM) has attracted researcher's attention for its biomedical applications. Previously, we fabricated a biomimetic spongy scaffold from decellularized WJ-ECM and, in this study, we sought to examine the osteogenic inductive potential of this scaffold and its underlying mechanism. To address this question, mesenchymal stem cells (MSCs) were isolated from WJ using a mechanical method and cultured on the scaffold, under dynamic condition, for over 21 days in the presence or absence of osteogenic medium. The status of signalling pathways involved in the osteogenic differentiation and the expression profile of integrins in the WJ-derived MSCs (WJ-MSCs) were examined. WJ-MSCs displayed differentiation capacities and expressed surface antigens, characteristics of MSCs. Histologically, WJ-MSCs seeded on the scaffold showed a proper cellular attachment, penetration and migration. They also exhibited a higher degree of alkaline phosphatase activity, calcium deposition and osteogenic gene expression, than those cultured in 2D condition. The expression of Wnt, BMP and TGF-beta signalling target genes together with that of alpha 2, alpha v and beta 1 integrins was increased in WJ-MSCs in both presence and absence of osteogenic induction medium. Taken together, our results demonstrate that WJ-derived scaffold induces osteogenic differentiation of WJ-MSCs, possibly through activating integrins and subsequently conventional intracellular signalling pathways.