The regulation of osteogenesis by ECM rigidity in MC3T3-E1 cells requires MAPK activation.

摘要: Once thought to provide only structural support tissues by acting as a scaffold which cells bind, it is now widely recognized that the extracellular matrix (ECM) provides instructive signals dictate cell behavior. Recently we demonstrated mechanical cues intrinsic ECM directly regulate behavior of pre-osteoblastic MC3T3-E1 cells. We hypothesized one possible mechanism compliance exerts its influence on osteogenesis modulating mitogen-activated protein kinase (MAPK) pathway. To address this hypothesis, differentiation cultured poly(ethylene glycol) (PEG)-based model substrates with tunable properties was assessed. Alkaline phosphatase (ALP) levels at days 7 and 14 were found be significantly higher in grown stiffer (423.9 kPa hydrogels rigid tissue culture polystyrene (TCPS) control) than soft hydrogel (13.7 kPa). Osteocalcin (OCN) bone sialoprotein (BSP) gene expression followed similar trend. In parallel, MAPK activity both time points. Inhibiting activation pharmacologically, using PD98059, resulted lower ALP levels, OCN, BSP hydrogels. Interestingly, effectiveness PD98059 itself dependent substrate stiffness, marked inhibition phosphorylation compliant but insignificant reduction TCPS. Together, these data confirm role for regulation osteogenic compliance.