Nitric Oxide Interacts with Caveolin-1 to Facilitate Autophagy-Lysosome-Mediated Claudin-5 Degradation in Oxygen-Glucose Deprivation-Treated Endothelial Cells

• Published in: Molecular neurobiology Vol. 53; no. 9; pp. 5935 - 5947
• Main Authors: Liu, Jie, Weaver, John, Jin, Xinchun, Zhang, Yuan, Xu, Ji, Liu, Ke J., Li, Weiping, Liu, Wenlan
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2016; Springer Nature B.V
• Subjects: Animals; Autophagy; Autophagy - drug effects; Benzoates - pharmacology; Biomedical and Life Sciences; Biomedicine; Caveolin 1 - metabolism; Cell Biology; Claudin-5 - metabolism; Cytoskeleton; Endothelial Cells - cytology; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Endothelium; Glucose - deficiency; Imidazoles - pharmacology; Imines - pharmacology; Lysosomes - drug effects; Lysosomes - metabolism; Mice; Neurobiology; Neurology; Neurosciences; Nitric Oxide - metabolism; Nitric Oxide Synthase Type II - metabolism; Oxygen; Protein Transport - drug effects; Proteolysis - drug effects; Caveolin-1; Claudin-5; Autophagy; Oxygen-glucose deprivation; Lysosome
• ISSN: 0893-7648; 1559-1182
• DOI: 10.1007/s12035-015-9504-8

Using in vitro oxygen-glucose deprivation (OGD) model, we have previously demonstrated that 2-h OGD induces rapid, caveolin-1-mediated dissociation of claudin-5 from the cellular cytoskeletal framework and quick endothelial barrier disruption. In this study, we further investigated the fate of translocated claudin-5 and the mechanisms by which OGD promotes caveolin-1 translocation. Exposure of bEND3 cells to 4-h OGD, but not 2-h OGD plus 2-h reoxygenation, resulted in claudin-5 degradation. Inhibition of autophagy or the fusion of autophagosome with lysosome, but not proteasome, blocked OGD-induced claudin-5 degradation. Moreover, knockdown of caveolin-1 with siRNA blocked OGD-induced claudin-5 degradation. Western blot analysis showed a transient colocalization of caveolin-1, claudin-5, and LC3B in autolysosome or lipid raft fractions at 2-h OGD. Of note, inhibiting autophagosome and lysosome fusion sustained the colocalization of caveolin-1, claudin-5, and LC3B throughout the 4-h OGD exposure. EPR spin trapping showed increased nitric oxide (NO) generation in 2-h OGD-treated cells, and inhibiting NO with its scavenger C-PTIO or inducible nitric oxide synthase (iNOS) inhibitor 1400W prevented OGD-induced caveolin-1 translocation and claudin-5 degradation. Taken together, our data provide a novel mechanism underlying endothelial barrier disruption under prolonged ischemic conditions, in which NO promotes caveolin-1-mediated delivery of claudin-5 to the autophagosome for autophagy-lysosome-dependent degradation.