Abstract 3144: Neuroglobin Inhibits Oxygen-Glucose Deprivation-induced Mitochondrial Permeability Transition Pore Opening in Primary Cultured Mouse Cortical Neurons

Background: Accumulating evidences from our laboratory and others have demonstrated that neuroglobin (Ngb) is protective against hypoxic/ischemic brain injury, thus targeting Ngb may be a novel approach for endogenous neuroprotection, but the molecular mechanisms remain undefined. Mitochondrial permeability transition pore (mPTP) opening is a key mitochondrial response to hypoxia/ischemia, followed by release of mitochondrial factors such as Cyt c and activation of Caspase-dependent apoptosis pathways. In this study, we test our hypothesis that Ngb inhibits OGD-induced mPTP opening in primary neurons. Method: Primary mouse cortical neurons were transduced with AAV-Ngb to achieve Ngb over-expression and Ngb-shRNA to achieve Ngb knockdown. At day 9 of culture, primary neurons were subjected to 4 hr OGD followed by reoxygenation. Neurotoxicity was measured after 20 hr reoxygenation by LDH release assay. mPTP opening was measured at 4 hr after reoxygenation by testing mitochondria swelling, NAD release and Cyt c release. NAD release was also measured using isolated mitochondria treated with OGD after incubation with recombinant Ngb protein. Results: (1) Four hour OGD followed by 20 hr reoxygenation caused 40±4.5% neuron death; Ngb overexpression significantly reduced the death rate to 18±5.2% (n=5, p