Alsin and SOD1G93A Proteins Regulate Endosomal Reactive Oxygen Species Production by Glial Cells and Proinflammatory Pathways Responsible for Neurotoxicity
Alsin and SOD1G93A Proteins Regulate Endosomal Reactive Oxygen Species Production by Glial Cells and Proinflammatory Pathways Responsible for Neurotoxicity
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DOI：
10.1074/jbc.m111.279711
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发表时间：
2011-11-18
影响因子：
4.8
通讯作者：
Engelhardt, John F.
中科院分区：
文献类型：
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作者：
Li, Qiang;Spencer, Netanya Y.;Engelhardt, John F.
最近的研究表明，在家族性肌萎缩侧索硬化症（ALS）中观察到的运动神经元死亡的发病机制中，小胶质细胞增强了Nox2介导的活性氧（ROS）。在这种情况下，ALS突变形式的SOD 1增强Rac 1激活，导致增加的Nox 2依赖性小胶质细胞ROS的产生和神经元细胞死亡的小鼠。目前尚不清楚导致ALS的其他基因突变是否也通过类似的Nox依赖性途径发挥作用，以增强ROS介导的运动神经元死亡。在本研究中，我们试图了解是否alsin，这是突变的遗传青少年形式的ALS，功能收敛于Rac1依赖的途径上的SOD1（G93A），以调节Nox依赖的ROS的生产。我们的研究表明，神经胶质细胞表达SOD 1（G93 A）或野生型alsin诱导ROS的产生，Rac 1的激活，TNF α的分泌，和NF κ B B的激活，导致运动神经元存活减少的共培养。有趣的是，alsin或针对Nox 2的shRNA与SOD1（G93A）在神经胶质细胞中的共表达减弱了这些促炎指标并保护了共培养中的运动神经元，尽管针对Nox 1和Nox 4的shRNA几乎没有影响。SOD 1（G93 A）表达以Rac 1依赖性方式显着增强神经胶质细胞中TNF α介导的内体活性氧，而alsin过表达抑制SOD 1（G93 A）诱导的内体活性氧和Rac 1激活。SOD1（G93 A）表达增强了Alsin向神经胶质细胞内膜区室的募集，表明这两种蛋白调节Nox 2依赖的内体ROS和调节NF κ B B的促炎信号。这些研究表明，由内体ROS调节的神经胶质促炎信号受到已知引起ALS的两种基因产物的影响。
Recent studies have implicated enhanced Nox2-mediated reactive oxygen species (ROS) by microglia in the pathogenesis of motor neuron death observed in familial amyotrophic lateral sclerosis (ALS). In this context, ALS mutant forms of SOD1 enhance Rac1 activation, leading to increased Nox2-dependent microglial ROS production and neuron cell death in mice. It remains unclear if other genetic mutations that cause ALS also function through similar Nox-dependent pathways to enhance ROS-mediate motor neuron death. In the present study, we sought to understand whether alsin, which is mutated in an inherited juvenile form of ALS, functionally converges on Rac1-dependent pathways acted upon by SOD1(G93A) to regulate Nox-dependent ROS production. Our studies demonstrate that glial cell expression of SOD1(G93A) or wild type alsin induces ROS production, Rac1 activation, secretion of TNF alpha, and activation of NF kappa B, leading to decreased motor neuron survival in co-culture. Interestingly, coexpression of alsin, or shRNA against Nox2, with SOD1(G93A) in glial cells attenuated these proinflammatory indicators and protected motor neurons in co-culture, although shRNAs against Nox1 and Nox4 had little effect. SOD1(G93A) expression dramatically enhanced TNF alpha-mediated endosomal ROS in glial cells in a Rac1-dependent manner and alsin overexpression inhibited SOD1(G93A)-induced endosomal ROS and Rac1 activation. SOD1(G93A) expression enhanced recruitment of alsin to the endomembrane compartment in glial cells, suggesting that these two proteins act to modulate Nox2-dependent endosomal ROS and proinflammatory signals that modulate NF kappa B. These studies suggest that glial proinflammatory signals regulated by endosomal ROS are influenced by two gene products known to cause ALS.