Protein phosphatase inhibitors and heat preconditioning prevent Hsp27 dephosphorylation, F-actin disruption and deterioration of morphology in ATP-depleted endothelial cells

摘要: The vascular endothelium response to ischemic depletion of ATP was studied in vitro. Endothelial cells (EC) cultured from human aorta or umbilical vein were incubated a glucose-free medium containing CCCP rotenone. Such blockade energy metabolism caused drop ATP, destruction actin filaments, morphological changes, and eventually disintegration EC monolayer within 2–2.5 h. While fell F-actin collapsed, the 27-kDa heat shock protein (Hsp27) lost basal phosphorylation became Triton X-100-insoluble forming granules inside cell nuclei. Protein phosphatase (PP) inhibitors (okadaic acid, cantharidin, sodium orthovanadate) did not delay decrease energy-deprived but arrested both alterations Hsp27 status changes for worse morphology. Similarly, dephosphorylation/insolubilization/granulation cytoskeletal disturbances resulting lack suppressed heat-preconditioned (thermotolerant) cultures, this effect being sensitive quercetin, blocker Hsp induction. longer preservation cytosolic pool phosphorylated during PP inhibitor-treated thermotolerant correlated with acquired resistance These data suggest that as well heat-inducible Hsp(s) can protect ischemia-stressed by preventing loss-provoked dephosphorylation breakdown cytoskeleton.