Nicotinamide Mononucleotide Adenylyltransferase 1 Regulates Cerebral Ischemia-Induced Blood-Brain Barrier Disruption Through NAD+/SIRT1 Signaling Pathway

The molecular mechanisms of blood-brain barrier (BBB) disruption in the early stage after ischemic stroke are poorly understood. In the present study, we investigated the potential role of nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) in ischemia-induced BBB damage using an animal middle cerebral artery occlusion (MCAO) model of ischemic stroke. Recombinant human NMNAT1 (rh-NMNAT1) was administered intranasally and Sirtuin 1 (SIRT1) siRNA was administered by intracerebroventricular injection. Our results indicate that rh-NMNAT1 reduced infarct volume, improved functional outcome, and decreased BBB permeability in mice after ischemic stroke. Furthermore, rh-NMNAT1 prevented the loss of tight junction proteins (occludin and claudin-5) and reduced cell apoptosis in ischemic microvessels. NMNAT1-mediated BBB permeability was correlated with the elevation of nicotinamide adenine dinucleotide (NAD(+))/NADH ratio and SIRT1 level in brain microvascular endothelial cells. In addition, rh-NMNAT1 treatment significantly decreased the levels of acetylated nuclear factor-kappa B, acetylated p53, and matrix metalloproteinase-9 in ischemic microvessels. Moreover, the protective effects of rh-NMNAT1 could be reversed by SIRT1 siRNA. In conclusion, these findings indicate that rh-NMNAT1 protects BBB integrity after cerebral ischemia via the NAD(+)/SIRT1 signaling pathway in brain microvascular endothelial cells. NMNAT1 may be a novel potential therapeutic target for reducing BBB disruption after ischemic stroke.

Automated summary

This study investigates the potential role of nicotinamide mononucleotide adenylyltransferase 1 (NMNAT1) in blood-brain barrier (BBB) damage after ischemic stroke. The results suggest that recombinant human NMNAT1 (rh-NMNAT1) can reduce infarct volume, improve functional outcome, and decrease BBB permeability. The protective effects of rh-NMNAT1 may be mediated through the regulation of nicotinamide adenine dinucleotide (NAD(+))/NADH ratio and Sirtuin 1 (SIRT1) level. Rh-NMNAT1 treatment can also decrease the levels of acetylated nuclear factor-kappa B, acetylated p53, and matrix metalloproteinase-9 in ischemic microvessels. The findings indicate that NMNAT1 may be a potential therapeutic target for reducing BBB disruption after ischemic stroke.