Cyclic mechanical stretch activates the NFkB, MAPK/ERK1/2 and PI3K pathways in ARCMs.

<p><b>A</b>) Isolated ARCMs attached to laminin were subjected to 24 h of cyclic mechanical stretch (10% stretch). Non-stretched control (0% stretch) ARCMs attached to laminin were incubated under identical conditions. Cells were then lysed, fractionated into cytosolic (C) and nuclear (N) fractions and immunoblotted with an anti-NFkB p65 antibody. In stretched ARCMs, the nuclear fraction contained significantly more of the NFkB p65 subunit compared to the non-stretched controls. Relative intensity of nuclear to cytoplasmic (N/C) fraction was determined. An antibody to the anti-TATA-binding protein (TBP) was used to determine fractionation efficiency. Cyclic mechanical stretch for 24 h induced a significant increase in MAPK/ERK1/2 and PI3K activity in isolated ARCMs attached to laminin. Isolated ARCMs were allowed to attach to laminin for 24 h and subsequently subjected to 24 h of cyclic mechanical stretch (10% stretch) or no stretch (0% stretch). Cells were lysed and immunoblotted for (<b>B</b>) ERK1/2 activity using an antibody against phospho-ERK1/2 (pERK) or a total ERK1/2 antibody (tERK) or for (<b>C</b>) PI3K activity via an antibody against phospho-AKT (pAKT) or total AKT (tAKT). Relative intensity of pERK/tERK or pAKT/tAKT was determined. *<i>P</i><0.05; ***<i>P</i><0.001; One-Way ANOVA with a Bonferroni post-test was used to determine the statistical significance of data. The values represent the average of three independent experiments.