Twisting integrin receptors increases endothelin-1 gene expression in endothelial cells

A magnetic twisting stimulator was developed based on the previously publis hed technique of magnetic twisting cytometry. Using ligand-coated ferromagn etic microbeads, this device can apply mechanical stresses with varying amp litudes, duration, frequencies, and waveforms to specific cell surface rece ptors. Biochemical and biological responses of the cells to the mechanical stimulation can be assayed. Twisting integrin receptors with RGD (Arg-Gly-A sp)-containing peptide-coated beads increased endothelin-1 (ET-1) gene expr ession by > 100%. In contrast, twisting scavenger receptors with acetylated low-density lipoprotein-coated beads or twisting HLA antigen with anti-HLA antibody-coated beads did not lead to alterations in ET-1 gene expression. In situ hybridization showed that the increase in ET-1 mRNA was localized in the cells that were stressed with the RGD-coated beads. Blocking stretch -activated ion channels with gadolinium, chelating Ca2+ with EGTA, or inhib iting tyrosine phosphorylation with genistein abolished twist-induced ET-1 mRNA elevation. Abolishing cytoskeletal tension with an inhibitor of the my osin ATPase, with an inhibitor of myosin light chain kinase, or with an act in microfilament disrupter blocked twisted-induced increases in ET-1 expres sion. Our results are consistent with the hypothesis that the molecular str uctural linkage of integrin-cytoskeleton is an important pathway for stress -induced ET-1 gene expression.