i NOS induces vascular endothelial cell migration and apoptosis via autophagy in ischemia/reperfusion injury

Abstract

Background/Aims: Inducible nitric oxide synthase (iNOS) plays a crucial role in ischemia/reperfusion (I/R). Autophagy is involved in irreversible cell injury and death under extreme conditions. However, whether iNOS mediates myocardial ischemia/reperfusion (I/R) injury in endothelial cells via autophagy remains ill-defined. In this study, we examined whether I/R-mediated up-regulation of iNOS is critical in the modulation of cell migration and apoptosis via autophagy in human umbilical vein endothelial cells (HUVECs). Methods: iNOS expression was detected in HUVECs using Western blotting analyses and immunocytochemistry. An in vitro scratch assay was performed to detect cell migration. The autophagy markers ATG5, LC3B and BECN were detected using Western blotting analysis and adenovirus-mRFP-GFP-LC3. The pharmacological inhibitor of autophagy 3-MA was also applied to confirm the role of autophagy in I/R. Results: I/R induced the expression of iNOS, which subsequently increased the migration and apoptosis of HUVECs and was associated with the up-regulation of autophagy. The iNOS specific inhibitor L-NAME abolished I/R-induced autophagy, while L-NAME and 3-MA both attenuated cell apoptosis and migration induced by I/R. Conclusion: These findings suggested that I/R-induced iNOS regulates migration and apoptosis in HUVECs via autophagy, which indicates a new therapeutic strategy for individuals with I/R injury.