Activation of neuronal NMDA receptors induces superoxide-mediated oxidative stress in neighboring neurons and astrocytes.
Activation of neuronal NMDA receptors induces superoxide-mediated oxidative stress in neighboring neurons and astrocytes.
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DOI：
10.1523/jneurosci.1597-12.2012
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发表时间：
2012-09-12
期刊：
影响因子：
--
通讯作者：
Swanson RA
中科院分区：
文献类型：
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作者：
Reyes RC;Brennan AM;Shen Y;Baldwin Y;Swanson RA
兴奋性毒性神经元死亡在一定程度上是由NMDA受体诱导的NOX2激活介导的，NOX2是一种产生超氧化物和由此产生的氧化应激的酶。然而，目前尚不清楚超氧化物是在细胞内空间产生，在响应NMDA受体激活的神经元中产生氧化应激，还是在细胞外空间产生，在邻近细胞中产生氧化应激。我们通过制备无法形成功能性NOX2复合物的p47phox - / -小鼠皮质神经元培养物，并以低密度转染gfp标记的p47phox，以在广泛分散的神经元中重建NOX2活性，来评估这些替代方法。在未转染的p47-phox - / -培养物中，NMDA暴露不会诱导氧化应激或细胞死亡，但在转染的nox2胜任神经元周围的神经元中确实会产生氧化应激和神经元死亡。通过与超氧化物歧化酶或阴离子通道阻滞剂4 ' -二异硫氰酸二苯乙烯-2,2 ' -二磺酸共孵育，可以阻断nmda诱导的氧化损伤在细胞间的扩散，证实了超氧化物阴离子是中介氧化剂。在预先存在的星形胶质细胞层上的神经元中，NMDA诱导神经元和星形胶质细胞的氧化应激，这种氧化应激再次被超氧化物歧化酶阻止。这些发现表明，一个神经元上的NMDA受体的激活可以通过NOX2在细胞外释放超氧化物的过程导致邻近神经元和星形胶质细胞的氧化应激和细胞死亡。
Excitotoxic neuronal death is mediated in part by NMDA receptor-induced activation of NOX2, an enzyme that produces superoxide and resultant oxidative stress. It is not known, however, whether the superoxide is generated in the intracellular space, producing oxidative stress in the neurons responding to NMDA receptor activation, or in the extracellular space, producing oxidative stress in neighboring cells. We evaluated these alternatives by preparing cortical neuron cultures from p47phox−/− mice, which are unable to form a functional NOX2 complex, and transfecting the cultures at low density with GFP-tagged p47phox to reconstitute NOX2 activity in widely scattered neurons. NMDA exposure did not induce oxidative stress or cell death in the non-transfected, p47-phox−/− cultures, but did produce oxidative stress and neuronal death in neurons surrounding the transfected, NOX2-competent neurons. This cell-to-cell spread of NMDA-induced oxidative injury was blocked by co-incubation with either superoxide dismutase or the anion channel blocker 4′-diisothiocyanostilbene-2,2′-disulphonate, confirming superoxide anion as the mediating oxidant. In neurons plated on a pre-existing astrocyte layer, NMDA induced oxidative stress in both the neurons and the astrocytes that was again prevented by superoxide dismutase. These findings show that activation of NMDA receptors on one neuron can lead to oxidative stress and cell death in neighboring neurons and astrocytes by a process involving the extracellular release of superoxide by NOX2.