부산대학교 도서관

Background and Purpose Nitric oxide ( NO) derived from e NOS is mostly responsible for the maintenance of vascular homeostasis and its decreased bioavailability is characteristic of reactive oxygen species ( ROS)-induced endothelial dysfunction ( ED). Because 5,5-dimethyl-1-pyrroline- N-oxide ( DMPO), a commonly used spin trap, can control intracellular nitroso-redox balance by scavenging ROS and donating NO, it was employed as a cardioprotective agent against ED but the mechanism of its protection is still not clear. This study elucidated the mechanism of protection by DMPO against SIN-1-induced oxidative injury to bovine aortic endothelial cells ( BAEC). Experimental Approach BAEC were treated with SIN-1, as a source of peroxynitrite anion ( ONOO−), and then incubated with DMPO. Cytotoxicity following SIN-1 alone and cytoprotection by adding DMPO was assessed by MTT assay. Levels of ROS and NO generation from HEK293 cells transfected with wild-type and mutant e NOS c DNAs, tetrahydrobiopterin bioavailability, e NOS activity, e NOS and Akt kinase phosphorylation were measured. Key Results Post-treatment of cells with DMPO attenuated SIN-1-mediated cytotoxicity and ROS generation, restoration of NO levels via increased in e NOS activity and phospho-e NOS levels. Treatment with DMPO alone significantly increased NO levels and induced phosphorylation of e NOS Ser1179 via Akt kinase. Transfection studies with wild-type and mutant human e NOS confirmed the dual role of e NOS as a producer of superoxide anion ( O2−) with SIN-1 treatment, and a producer of NO in the presence of DMPO. Conclusion and Implications Post-treatment with DMPO of oxidatively challenged cells reversed e NOS dysfunction and could have pharmacological implications in the treatment of cardiovascular diseases. [ABSTRACT FROM AUTHOR]