Abstract:

BACKGROUND: Although little is known about the molecular mechanisms by which mechanical signals regulate mesenchymal stem cells (MSCs) differentiation, cytoskeleton may play an important role in procedure of intracellular mechanical signal delivering.
OBJECTIVE: To investigate the change of the spatial structure of filamentous actin (F-actin), a cytoskeleton protein, under the continuous hydrostatic pressure and the effects of ERK1/2 signaling pathway or integrin α2β1 block on the above-mentioned process.
METHODS: In vitro cultured hBMSCs were incubated under continuous pressure of 40 or 80 kPa for 1 or 4 hours by hydraulic pressure controlled cellular strain unit, with or without blocking the ERK1/2 signaling pathway by 10 mmol/L U0126 or by 10 mg/L anti-integrin α2β1 antibody.
RESULTS AND CONCLUSION: The actin filaments of the strained BMSCs were more flimsy and tenuous than untreated osteoblasts and unlike the normal distribution of bundles or membrane-like of the control group, and they were arranged without direction. But after stained for 4 hours cells showed an arrangement more near the unstained cells than after stained for 1 hour. The U0126 interrupted the rearrangement phenomenon of BMSCs under hydraulic pressure more severely than the anti-integrin α2β1 antibody did. BMSCs under hydrostatic compressive loading lead to cytoskeletal reorganization and rearrangement; The ERK1/2 signaling pathway plays an important role in the process.