1148 Ethanol augments stimulated microvesicle particle formation and release in a keratinocyte cell line

Abstract

Microvesicle particles (MVP) are defined as submicron vesicles generated from cellular membranes via exocytosis in an active energy-dependent means. They are irregularly shaped and range from ∼100-1000 nm in size. MVP generation occurs in response to various stimuli, many involving intracellular calcium mobilization. MVP contain a variety of bioactive substances such as proteins, lipids, cytokines, and nucleic acids which can be transferred from parent cell to either nearby or even distant cells. MVP have been hypothesized to play pathological roles in the development of many human disease states. Previous studies by our group suggest that activation of the receptor for the lipid mediator Platelet-activating factor (1-alkyl-2-acetyl-glycerophosphocholine; PAF) results in MVP release in epithelial cell lines, primary keratinocytes and human and murine skin. Because ethanol can augment PAF production in keratinocytes and skin in response to various stressors including ultraviolet B radiation and thermal burn injury, the current studies were designed to test if ethanol can augment MVP production. Human HaCaT keratinocytes were pre-treated with ethanol before stimulation with ultraviolet B radiation, thermal burn injury, the PAF agonist CPAF, or the phorbol ester TPA. MVP released were quantified with a Nanosight particle counter. Ethanol pretreatment augmented both baseline as well as stimulated MVP production in a time-dependent manner. These studies provide a potential mechanism for ethanol-mediated pathologies, namely, via the augmentation of MVP production.