The inhibition of apoptosis by melatonin in VSC4.1 motoneurons exposed to oxidative stress, glutamate excitotoxicity, or TNF-alpha toxicity involves membrane melatonin receptors.
The inhibition of apoptosis by melatonin in VSC4.1 motoneurons exposed to oxidative stress, glutamate excitotoxicity, or TNF-alpha toxicity involves membrane melatonin receptors.
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DOI：
10.1111/j.1600-079x.2009.00739.x
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发表时间：
2010-03
影响因子：
10.3
通讯作者：
Banik NL
中科院分区：
文献类型：
--
作者：
Das A;McDowell M;Pava MJ;Smith JA;Reiter RJ;Woodward JJ;Varma AK;Ray SK;Banik NL
运动神经元的丧失可能是与中枢神经系统损伤和疾病相关的一些运动功能缺陷的基础。我们测试了褪黑激素，一种有效的抗氧化剂和自由基清除剂，是否会阻止暴露于毒素后的运动神经元凋亡，以及这种神经保护是否由褪黑激素受体介导。Wright染色和ApopTag检测显示，VSC4.1运动神经元暴露于50 μM H2O2、25 μM谷氨酸（LGA）或50 ng/ml肿瘤坏死因子-α (TNF-α) 24小时后，凋亡显著增加。mRNA和蛋白分析显示，凋亡过程中应激激酶和半胱氨酸蛋白酶的表达和活性增加，线粒体膜电位丧失。这些损伤还引起细胞内游离[Ca2+]和钙蛋白酶和半胱天冬酶活性的增加。细胞暴露于应激刺激15分钟，然后用200 nM褪黑素处理。用褪黑素处理后的细胞减少了活性氧（ROS）的产生和p38、MAPK和JNK1的磷酸化，防止了细胞死亡，维持了全细胞膜电位，表明功能性神经保护。褪黑激素受体（MT1和MT2）在褪黑激素治疗后上调。为了证实MT1和MT2在提供神经保护方面的作用，我们将细胞用10 μM的luzindole（褪黑激素受体拮抗剂）后处理（20分钟）。Luzindole显著减弱褪黑素诱导的神经保护作用，表明褪黑素至少在一定程度上通过其受体阻止VSC4.1运动神经元凋亡。提示褪黑素对运动神经元的神经保护作用是受体介导的，可能是一种有效的神经保护剂，可减轻中枢神经系统损伤和疾病中运动神经元的死亡。
Loss of motoneurons may underlie some of the deficits in motor function associated with CNS injuries and diseases. We tested whether melatonin, a potent antioxidant and free radical scavenger, would prevent motoneuron apoptosis following exposure to toxins and whether this neuroprotection is mediated by melatonin receptors. Exposure of VSC4.1 motoneurons to either 50 μM H2O2, 25 μM glutamate (LGA), or 50 ng/ml tumor necrosis factor-alpha (TNF-α) for 24 h caused significant increases in apoptosis, as determined by Wright staining and ApopTag assay. Analyses of mRNA and proteins showed increased expression and activities of stress kinases and cysteine proteases and loss of mitochondrial membrane potential during apoptosis. These insults also caused increases in intracellular free [Ca2+] and activities of calpain and caspases. Cells exposed to stress stimuli for 15 min were then treated with 200 nM melatonin. Post-treatment of cells with melatonin attenuated production of reactive oxygen species (ROS) and phosphorylation of p38, MAPK, and JNK1, prevented cell death, and maintained whole-cell membrane potential, indicating functional neuroprotection. Melatonin receptors (MT1 and MT2) were upregulated following treatment with melatonin. To confirm the involvement of MT1 and MT2 in providing neuroprotection, cells were post-treated (20 min) with 10 μM luzindole (melatonin receptor antagonist). Luzindole significantly attenuated melatonin-induced neuroprotection, suggesting that melatonin worked, at least in part, via its receptors to prevent VSC4.1 motoneuron apoptosis. Results suggest that neuroprotection rendered by melatonin to motoneurons is receptor mediated and melatonin may be an effective neuroprotective agent to attenuate motoneuron death in CNS injuries and diseases.