Necrostatin-1 prevents the proapoptotic protein Bcl-2/adenovirus E1B 19-kDa interacting protein 3 from integration into mitochondria.

Necrostatin-1 (Nec-1) has previously been shown to protect neurons from death in traumatic and ischemic brain injuries. This study tests the hypothesis that Nec-1 protects neural cells against traumatic and ischemic brain injuries through inhibition of the Bcl-2/adenovirus E1B 19-kDa interacting protein 3 (BNIP3). We have used biochemical and morphological techniques to determine the inhibition of Nec-1 on BNIP3-induced cell death and to identify its mechanism of action in in vivo and in vitro models of neurodegeneration. Here we show that Nec-1 significantly increased neuronal viability following prolonged exposure to hypoxia in vitro, and attenuated myelin damage and neuronal death in traumatic brain injury and cerebral ischemia in Sprague-Dawley rats. Nec-1 alleviated traumatic brain injury-induced up-regulation of BNIP3 in mature oligodendrocytes. In isolated mitochondria, Nec-1 prevented BNIP3 from integrating into mitochondria by modifying its binding sites on the mitochondria. Consequently, Nec-1 robustly inhibited BNIP3-induced collapse of mitochondrial membrane potential and reduced the opening probability of mitochondrial permeability transition pores. Nec-1 also preserved mitochondrial ultrastructure and suppressed BNIP3-induced nuclear translocation of apoptosis-inducing factor. In conclusion, Nec-1 protects neurons and oligodendrocytes against traumatic and ischemic brain injuries by targeting the BNIP3-induced cell death pathway, and is a novel inhibitor for BNIP3. Cover Image for this issue: https://doi.org/10.1111/jnc.15056.

CNS limited ANCA-associated vasculitis presenting as an isolated intraparenchymal mass.

The authors report a 34-year-old male with antineutrophil cytoplasmic autoantibody (ANCA) associated vasculitis (AAV) which only involved the central nervous system and presented with an isolated mass in the left parietal lobe. Constitutional symptoms were lacking and the only symptom was progressive right-sided hemiparesis. Pathology suggested necrotizing vasculitis without eosinophils and granulomas. Cytoplasmic ANCA was elevated to 103.9 IU/ml (>5 times the upper limit) in serum. He obtained a regression following treatment of cyclophosphamide and steroids. Prompt diagnosis of AAV is essential since early and aggressive initiation of immunosuppressive therapy can avoid further neurological sequelae.

Pranlukast, a cysteinyl leukotriene receptor-1 antagonist, protects against chronic ischemic brain injury and inhibits the glial scar formation in mice.

We have recently reported the neuroprotective effect of pranlukast (ONO-1078), a cysteinyl leukotriene receptor-1 (CysLT1) antagonist, on cerebral ischemia in rats and mice. In this study, we further determined whether the effect of pranlukast is long lasting and related to the formation of a glial scar in cerebral ischemic mice. Focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO). After ischemia, pranlukast (0.1 mg/kg) was injected intraperitoneally for 5 consecutive days. Neurological deficits and sensorimotor function were determined during 70 days after ischemia. Brain lesion and glial scar formation were detected at the end of the experiment. Pranlukast did not reduce mortality, but significantly improved neurological deficits and promoted sensorimotor recovery during 70 days. At the end of the experiment, pranlukast significantly reduced lesion volume, and increased neuron densities in the cortex and hippocampal CA1 region in the ischemic hemispheres. Importantly, pranlukast also remarkably reduced the thickness of a scar wall in the ischemic hemispheres. These findings indicate that pranlukast has a long-lasting protective effect on focal cerebral ischemia in mice, and inhibit the ischemia-induced glial scar formation, providing further evidence of the therapeutic potential of pranlukast in the treatment of ischemic stroke.

Excessive autophagy contributes to neuron death in cerebral ischemia.

AIMS: To determine the extent to which autophagy contributes to neuronal death in cerebral hypoxia and ischemia. METHODS: We performed immunocytochemistry, western blot, cell viability assay, and electron microscopy to analyze autophagy activities in vitro and in vivo. RESULTS: In both primary cortical neurons and SH-SY5Y cells exposed to oxygen and glucose deprivation (OGD)for 6 h and reperfusion (RP) for 24, 48, and 72 h, respectively, an increase of autophagy was observed as determined by the increased ratio of LC3-II to LC3-I and Beclin-1 (BECN1) expression. Using Fluoro-Jade C and monodansylcadaverine double-staining, and electron microscopy we found the increment in autophagy after OGD/RP was accompanied by increased autophagic cell death, and this increased cell death was inhibited by the specific autophagy inhibitor, 3-methyladenine. The presence of large autolysosomes and numerous autophagosomes in cortical neurons were confirmed by electron microscopy. Autophagy activities were increased dramatically in the ischemic brains 3-7 days postinjury from a rat model of neonatal cerebral hypoxia/ischemia as shown by increased punctate LC3 staining and BECN1 expression. CONCLUSION: Excessive activation of autophagy contributes to neuronal death in cerebral ischemia.

The proapoptotic member of the Bcl-2 family Bcl-2 / E1B-19K-interacting protein 3 is a mediator of caspase-independent neuronal death in excitotoxicity.

Caspase-independent neuronal death has been shown to occur in neuroexcitotoxicity. Here, we tested the hypothesis that the gene encoding Bcl-2/E1B-19K-interacting protein 3 (BNIP3) mediates caspase-independent neuronal death in excitotoxicity. BNIP3 was not detectable in neurons under normal condition. BNIP3 expression was increased dramatically in neurons in both in vivo and in vitro models of excitotoxicity. Expression of full-length BNIP3 in primary hippocampal neurons induced atypical cell death that required protein synthesis but was largely independent of caspase activities. Inhibition of BNIP3 expression by RNA interference protected against glutamate-induced neuronal cell death. Thus, BNIP3 activation and expression appears to be both necessary and sufficient for neuronal apoptosis in excitotoxicity. These results suggest that BNIP3 may be a new target for neuronal rescue strategies.