The proteome of endothelial cells.

Endothelial cells form a continuous monolayer lining the inside face of all blood vessels, and present the ability to selectively control vascular permeability. The endothelium is involved in a wide variety of normal physiological and pathological processes. The endothelial dysfunction occurs under activation conditions, with the acquisition of many new functional, inflammatory, and immune properties, and as a consequence, endothelial cells display many different transcription profiles. We describe here the isolation and culture of the most useful model of human umbilical vein endothelial cells, and undertake the proteomic analysis under both basal quiescent condition and activated by stimulation with a proinflammatory cytokine. Series of two-dimensional electrophoresis have allowed us to detect a total of close to 600 polypeptide spots using 4.0-7.0 pH range in both culture conditions. We have selected 233 proteins by cross-matching the gels, and found that 70% showed an increase and 30% a decrease of expression levels in activated cells. Subsequent identification of 35 altered peptides is made by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry, as well as a study of posttranslational modifications. These global findings may contribute to understand the effects of pathological stimuli and the mechanisms that regulate vascular diseases.