Simulation of Microgravity and Coculturing with Hematopoietic Cells Oppositely Modulate Wnt Signaling in Mesenchymal Stromal Cells.

The osteogenic potential of mesenchymal stromal cells (MSCs) can determine bone homeostasis and the physical characteristics of bones. Microgravity reduces the ability of these cells to differentiate in osteogenic direction. It has been shown that the addition of hematopoietic stem and progenitor cells (HSPCs) to MSC culture in vitro can have the opposite effect. The aim of this study was to identify transcriptional changes in 84 genes associated with Wnt signaling in MSCs during microgravity simulation and interaction with HSPCs. The results indicate an increase in the non-canonical Wnt signaling activity during coculturing of MSCs and HSPCs, while simulated microgravity enhances the canonical component of this signaling pathway. These changes may underlie the modulation of osteogenic potential of MSCs in hematopoietic niche under microgravity.