Figure 4. The effect of exogenous, macrophage-derived soluble factors on ECM-sensitive regulation of miR18a.

U373-MG cells were incubated with fluorescent probes for miR18a after prior incubation with medium conditioned for 4 days by C8-B4 macrophages. Cells cultured on high-fibronectin locations on the gel showed high miR18a expression, while cells were relatively insensitive to substrate stiffness at all fibronectin densitites. (a) Iso-fibronectin curves showed no mechanosensitivity of miR18a expression in cells cultured in macrophage-conditioned medium (b). Contrary to the reduction of mechanosensitivity, fibronectin sensitivity remained at all iso-stiffness points when cells were cultured in macrophage-conditioned medium (c). N>30 cells for each stiffness-ligand density combination measurement of miR18a.