Tajes Orduña Marta, Pelegrí Gabalda Carme, Vilaplana Hortensi Jordi, Pallàs Lliberia Mercè, Camins Espuny Antoni
Centro de Investigación de Biomedicina en Red en Enfermedades Neurodegenerativas (CIBERNED), Unitat de Farmacologia i Farmacognòsia and Institut de Biomedicina (IBUB), Barcelona, Spain.
J Pineal Res. 2009 Apr;46(3):262-7. doi: 10.1111/j.1600-079X.2008.00656.x. Epub 2009 Jan 31.
The neuroprotective effects of melatonin in an experimental model of aging-induced apoptosis have been examined. Cerebellar granule neurons show characteristics of apoptosis after 17 days in culture (DV). The addition of melatonin to neuronal cell cultures (100-500 mum) resulted in neuroprotective and antiapoptotic effects, which were revealed by nuclear condensed cell counting. In a thorough analysis by Western-blot of the potential pathways responsible for melatonin's neuroprotective effects, we found an increase in the activation of prosurvival Akt. Subsequently GSK3beta inhibition and an increase in p-FOXO1 phosphorylation occurred. In this model of aging, apoptosis was associated with an elevated DNA damage, as demonstrated by an increase in the activation of ataxia telangiectasia muted (ATM). Subsequently, downstream targets such as p53 were activated. Furthermore, the process of DNA damage was coupled to an increase in the expression of certain proteins involved in cell cycle regulation; these were cyclin D and the proapoptotic transcription factor E2F-1. We conclude that the antiapoptotic effects of melatonin were mediated by two potential mechanisms: by increasing the activity of prosurvival pathways via Akt and by the prevention of DNA damage (via ATM inhibition) followed by the reduction of cell cycle re-entry.
褪黑素在衰老诱导的细胞凋亡实验模型中的神经保护作用已得到研究。培养17天后（DV），小脑颗粒神经元呈现出细胞凋亡的特征。向神经元细胞培养物中添加褪黑素（100 - 500 μM）可产生神经保护和抗凋亡作用，这通过核浓缩细胞计数得以揭示。在通过蛋白质免疫印迹法对褪黑素神经保护作用的潜在途径进行深入分析时，我们发现促生存蛋白激酶B（Akt）的激活增加。随后糖原合成酶激酶3β（GSK3β）受到抑制，叉头转录因子O1（FOXO1）的磷酸化增加。在这个衰老模型中，细胞凋亡与DNA损伤增加有关，这通过共济失调毛细血管扩张症突变基因（ATM）激活的增加得以证明。随后，诸如p53等下游靶点被激活。此外，DNA损伤过程与细胞周期调控中某些蛋白质表达的增加相关联；这些蛋白质是细胞周期蛋白D和促凋亡转录因子E2F - 1。我们得出结论，褪黑素的抗凋亡作用由两种潜在机制介导：通过增加促生存途径（经由Akt）的活性以及通过预防DNA损伤（经由抑制ATM），随后减少细胞周期重新进入。
