Nitric oxide (NO) dependant regulation of protein S‐nitrosation in pulmonary endothelial cells

Abstract

S-nitrosothiols are adducts of NO and cysteine thiol groups that can be formed in many mammalian tissues and are known to play a role in a variety of physiological functions including signal transduction and host defense. The biological effects of S-nitrosothiols may be regulated via 1) homolytic or heterolytic decomposition to NO; or 2) direct exchange of –NO function with thiol containing proteins (trans-S-nitrosation). Using 2-D gel electrophoresis and chemical revelation of S-nitrosated proteins followed by protein identification via MALDI TOF, we were able to detect NO-induced changes in S-nitrosation of the proteome of sheep pulmonary artery endothelial cells (SPAEC) exposed to the cell membrane-permeant nitric oxide donor L-S-Nitrosocyteine ethyl ester (L-SNCEE). S-nitrosation of several cellular proteins was observed including modification of hNRNP A3 and a homologue of PDI. Changes in protein S-nitrosation were also analyzed in mouse lung endothelial cells (MLEC) and human aortic endothelial cells (HAEC) exposed to L-SNCEE. We observed interspecies-differences (HAEC>SPAEC>MLEC) in the relative amounts of protein nitrosation after exposure to NO donor. These results indicate that NO may play an important role in the regulation of cellular signaling through post-translational protein modification and there are apparent species differences in the magnitude of such modification.