Cell Adhesion Decreases And Inhibition Of Mouse Mesenchymal Stem Cell'S Growth And Differentiation Under Simulated Microgravity

Objective: To explore the effect of simulated microgravity (SMG) on the cytoskeleton and adhesion of mouse mesenchymal stem cells (MSCs), and to detect the expression of specific genes related to cell growth and differentiation under SMG. Methods: Fluorescence staining was used to detect the changes of cytoskeleton morphology and focal adhesion plaque distribution in MSCs. The expression of CyclinB1 and Vinculin was detected by Western blot. RNA arrays were used to detect the transcription of genes related to MSCs growth and differentiation. Results: Microtubules and microfilaments of MSCs altered significantly under microgravity, accompanied by decreased distribution of focal adhesion plaques. Western blot analysis indicates that SMG causes inhibition of Vinculin and CyclinB1 expression. The expression of genes stimulating osteoblast growth and MSCs' osteogenic differentiation, including Bmp4, Igf1, and Sox9 are down-regulated, and the expression of genes, including Csf2, Gdf5, Il1 beta and Sox2 that are involved in inhibition of osteogenic differentiation, or stimulating the formation of osteoclasts are up-regulated under SMG, which are detected by RNA PCR Array. These findings may explain the inhibition effects of SMG on MSCs proliferation and osteoblast differentiation.