Dexamethasone inhibits U937 cell adhesion via the down-regulation of ROCK1 activity

Objective. To explore the effect of dexamethasone (DEX) on monocyte adhesion function and its underlying mechanism. Methods. The effects of DEX and fasudil on adhesion of cultured U937 monocytes to human umbilical vein endothelial cells (HUVEC) following stimulation with phorbol myristate acetate (PMA) were studied; Changes in the Rho-associated coiled-coil protein kinase 1 (ROCK1) protein content and activity were evaluated. Results. DEX and fasudil significantly inhibited U937 cell adhesion rates under PMA stimulation and inhibited ROCK1 activity. Mifepristone (RU-486) and cycloheximide (CHX) did not alter these effects of DEX. Conclusions. DEX interferes with the adhesion function of U937 cells through the inhibition of ROCK1 activity.