Skliris A, Papadaki O, Kafasla P, Karakasiliotis I, Hazapis O, Reczko M, Grammenoudi S, Bauer J, Kontoyiannis D L
Biomedical Sciences Research Centre 'Alexander Fleming', 16672 Vari, Greece.
Centre for Brain Research, Medical University of Vienna, A109 Vienna, Austria.
Cell Death Differ. 2015 May;22(5):703-18. doi: 10.1038/cdd.2014.158. Epub 2014 Oct 10.
Alterations in the functions of neuronal RNA-binding proteins (RBPs) can contribute to neurodegenerative diseases. However, neurons also express a set of widely distributed RBPs that may have developed specialized functions. Here, we show that the ubiquitous member of the otherwise neuronal Elavl/Hu family of RNA-binding proteins, Elavl1/HuR, has a neuroprotective role. Mice engineered to lack exclusively HuR in the hippocampal neurons of the central nervous system (CNS), maintain physiologic levels of neuronal Elavls and develop a partially diminished seizure response following strong glutamatergic excitation; however, they display an exacerbated neurodegenerative response subsequent to the initial excitotoxic event. This response was phenocopied in hippocampal cells devoid of ionotropic glutamate receptors in which the loss of HuR results in enhanced mitochondrial dysfunction, oxidative damage and programmed necrosis solely after glutamate challenge. The molecular dissection of HuR and nElavl mRNA targets revealed the existence of a HuR-restricted posttranscriptional regulon that failed in HuR-deficient neurons and is involved in cellular energetics and oxidation defense. Thus, HuR acts as a specialized controller of oxidative metabolism in neurons to confer protection from neurodegeneration.
神经元RNA结合蛋白(RBPs)功能的改变可能导致神经退行性疾病。然而,神经元也表达一组广泛分布的RBPs,它们可能具有特殊功能。在这里,我们表明,RNA结合蛋白神经元Elavl/Hu家族中普遍存在的成员Elavl1/HuR具有神经保护作用。经基因工程改造后,中枢神经系统(CNS)海马神经元中仅缺乏HuR的小鼠,其神经元Elavls维持生理水平,在强烈的谷氨酸能兴奋后癫痫反应部分减弱;然而,在最初的兴奋性毒性事件后,它们表现出加剧的神经退行性反应。在缺乏离子型谷氨酸受体的海马细胞中也出现了这种反应,其中HuR的缺失仅在谷氨酸刺激后导致线粒体功能障碍、氧化损伤和程序性坏死增强。对HuR和nElavl mRNA靶点的分子剖析揭示了存在一个受HuR限制的转录后调控子,该调控子在缺乏HuR的神经元中失效,并参与细胞能量代谢和氧化防御。因此,HuR作为神经元氧化代谢的特殊调节因子,可保护神经元免受神经退行性变。