Exogenous phospholipase C stimulates epithelial cell migration and integrin expression in vitro

Phospholipase C secreted by bacterial pathogens has been identified as a vi rulence factor in several human diseases and has been implicated in impedin g wound healing. The role of phospholipase C in the intracellular signal co ntrol of epithelial growth was studied in normal human skin keratinocytes c ultured in conditions simulating aspects of wound healing. Bacillus cereus phospholipase C decreased cell-cell contact and increased cell migration re sulting in disruption of the advancing epithelial sheet, Phospholipase C-in duced migration was blocked by inhibitor of the phosphoinositol signal tran sduction pathway neomycin sulfate and protein kinase C inhibitor RO-31-8220 . Induced migration was associated with elevated levels of matrix metallopr oteinase-9 which, when blocked by tissue inhibitor of metalloproteinase-1, was accompanied by a loss of migration. Adhesion studies showed that phosph olipase C treatment enhanced cell binding to fibronectin, vitronectin and c ollagen IV. Immunostained phospholipase C-stimulated cells cultured on fibr onectin showed enhanced expression and relocation of the integrin subunits alpha (v), alpha (5) and beta (1). Confocal microscopy showed that phosphol ipase C-induced levels of integrin subunit beta, were predominantly deposit ed on the basal surface of the cell apparently in focal contacts and associ ated with actin stress fibers. These results indicate that exogenous phosph olipase C signaling from a bacterial source may play an important role in p erturbing normal reepithelialization via altered expression of integrins an d matrix metalloproteinase-9.