Neuroglobin protects against nitric oxide toxicity

Neuroglobin (Ngb) is a novel vertebrate globin expressed principally in neurons. Ngb expression is induced by hypoxia and ischemia, and Ngb protects neurons against these insults. The mechanism of Ngb's protective action is unknown, but its ability to bind NO suggests that NO scavenging might be involved. To test this hypothesis, we treated wild type and Ngb-transfected HN33 (mouse hippocampal neuron × N18TG2 neuroblastoma) cells with NO donors and compared their sensitivity to NO-induced cell death. Ngb overexpression shifted concentration-toxicity curves to the right, indicating reduced susceptibility to NO or is metabolites. The results suggest that the ability of Ngb to neutralize the neurotoxic effects of reactive nitrogen species may be an important contributor to its neuroprotective properties.