Neddylation inhibition protects against ischemic brain injury

Abstract Neddylation is a ubiquitylation-like pathway that is critical in various cellular functions by conjugating NEDD8 to target proteins. However, the roles of neddylation in stroke, remain elusive. Here, we report that NEDD8 conjugation increased after ischemic stroke and was abundantly present in neutrophils, whereas cullin-1, a key substrate of neddylation, was upregulated in endothelium. Inhibition of neddylation by MLN4924, inactivated cullin-RING E3 ligase (CRL), reduced brain infarction and improved functional outcomes. MLN4924 treatment induced accumulation of the CRL substrate NF1. Knockdown of NF1 abolished MLN4924-dependent inhibition of neutrophil trafficking. These effects were mediated through activation of endothelial P-selectin and ICAM-1. Moreover, NF1 silencing blocked MLN4924-afforded BBB protection and neuroprotection through activation of PKCδ, MARCKS and MLC in cerebral microvessels. Our results demonstrate that increased neddylation promoted neutrophil trafficking and thus exacerbated injury of the BBB and stroke outcomes. We suggest that the neddylation inhibition may be beneficial in ischemic stroke.