Autophagy is involved in nanoalumina-induced cerebrovascular toxicity.

The current study focused on blood-brain barrier disruption and neurovascular damage induced by engineered nanomaterials. Exposure to nanoalumina, but not to nanocarbon, induced a dose-dependent mitochondrial potential collapse, increased autophagy of brain endothelial cells, and decreased expression of the tight-junction proteins occludin and claudin-5. Inhibition of autophagy by pretreatment with Wortmannin attenuated the effects of nanoalumina on decreased claudin-5 expression; however, it did not affect the disruption of occludin. These findings were confirmed in mice by administration of nanoalumina into the cerebral circulation. Systemic treatment with nanoalumina elevated autophagy-related genes and autophagic activity in the brain, decreased tight-junction protein expression, and elevated blood-brain barrier permeability. Finally, exposure to nanoalumina, but not to nanocarbon, increased brain infarct volume in mice subjected to a focal ischemic stroke model. Overall, our study reveals that autophagy constitutes an important mechanism involved in nanoalumina-induced neurovascular toxicity in the central nervous system. FROM THE CLINICAL EDITOR: In this paper, the effects of nanoalumina on the permeability of the blood-brain barrier is reported, suggesting that autophagy is an important mechanism in nanoalumina-induced neurovascular toxicity.