Rodríguez-Losada Noela, de la Rosa Javier, Larriva María, Wendelbo Rune, Aguirre José A, Castresana Javier S, Ballaz Santiago J
Dept. of Human Physiology & Physical Sports Education, Medical School, University of Málaga, Málaga, Spain.
Dept. of Biochemistry & Genetics, University of Navarra School of Sciences, Pamplona, Spain.
J Adv Res. 2020 Jan 22;23:37-45. doi: 10.1016/j.jare.2020.01.009. eCollection 2020 May.
Alpha-Synuclein (aSyn) is a chameleon-like protein. Its overexpression and intracellular deposition defines neurodegenerative α-synucleinopathies including Parkinson's disease. Whether aSyn up-regulation is the cause or the protective reaction to α-synucleinopathies remains unresolved. Remarkably, the accumulation of aSyn is involved in cancer. Here, the neuroblastoma SH-SY5Y cell line was genetically engineered to overexpress aSyn at low and at high levels. aSyn cytotoxicity was assessed by the MTT and vital-dye exclusion methods, observed at the beginning of the sub-culture of low-aSyn overexpressing neurons when cells can barely proliferate exponentially. Conversely, high-aSyn overexpressing cultures grew at high rates while showing enhanced colony formation compared to low-aSyn neurons. Cytotoxicity of aSyn overexpression was indirectly revealed by the addition of pro-oxidant rotenone. Pretreatment with partially reduced graphene oxide, an apoptotic agent, increased toxicity of rotenone in low-aSyn neurons, but, it did not in high-aSyn neurons. Consistent with their enhanced proliferation, high-aSyn neurons showed elevated levels of SMP30, a senescence-marker protein, and the mitosis Ki-67 marker. High-aSyn overexpression conferred to the carcinogenic neurons heightened tumorigenicity and resistance to senescence compared to low-aSyn cells, thus pointing to an inadequate level of aSyn stimulation, rather than the aSyn overload itself, as one of the factors contributing to α-synucleinopathy.
α-突触核蛋白（aSyn）是一种具有变色龙特性的蛋白质。其过度表达和细胞内沉积定义了包括帕金森病在内的神经退行性α-突触核蛋白病。aSyn上调是α-突触核蛋白病的病因还是保护性反应仍未明确。值得注意的是，aSyn的积累与癌症有关。在此，对神经母细胞瘤SH-SY5Y细胞系进行基因工程改造，使其低水平和高水平过度表达aSyn。通过MTT法和活细胞染料排斥法评估aSyn的细胞毒性，在低aSyn过表达神经元传代培养开始时观察到，此时细胞几乎无法呈指数增殖。相反，与低aSyn神经元相比，高aSyn过表达培养物生长速度快，且集落形成增强。添加促氧化剂鱼藤酮间接揭示了aSyn过表达的细胞毒性。用部分还原的氧化石墨烯（一种凋亡剂）预处理，可增加鱼藤酮对低aSyn神经元的毒性，但对高aSyn神经元无效。与增殖增强一致，高aSyn神经元中衰老标记蛋白SMP30和有丝分裂Ki-67标记物水平升高。与低aSyn细胞相比，高aSyn过表达赋予致癌神经元更高的致瘤性和抗衰老能力，因此表明aSyn刺激水平不足而非aSyn过载本身是导致α-突触核蛋白病的因素之一。
