Disruption of Protein Processing in the Endoplasmic Reticulum of DYT1 Knock-in Mice Implicates Novel Pathways in Dystonia Pathogenesis
Disruption of Protein Processing in the Endoplasmic Reticulum of DYT1 Knock-in Mice Implicates Novel Pathways in Dystonia Pathogenesis
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DOI：
10.1523/jneurosci.0669-16.2016
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发表时间：
2016-10-05
影响因子：
5.3
通讯作者：
Gonzalez-Alegre, Pedro
中科院分区：
文献类型：
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作者：
Beauvais, Genevieve;Bode, Nicole M.;Gonzalez-Alegre, Pedro
肌张力障碍1型（DYT 1）是一种显性遗传性神经系统疾病，由编码内质网（ER）驻留蛋白torsinA的基因TOR 1A突变引起。以前的工作主要是在基于细胞的系统中完成的，表明突变体torsinA改变了分泌途径中的蛋白质加工。我们假设在体内哺乳动物脑中诱导ER应激会触发或加剧突变型扭转蛋白A诱导的功能障碍。为了验证这一假设，我们将DYT 1基因敲入小鼠与p58（IPK）基因敲除小鼠杂交。ER共伴侣蛋白p58（IPK）与BiP相互作用，并通过帮助折叠ER货物来帮助蛋白质成熟。其缺失增加了细胞对ER应激的敏感性。我们发现DYT 1基因敲入/p58基因敲除小鼠的代数低于预期，这表明发育相互作用影响生存能力。然而，存活的动物没有表现出异常的运动功能。对脑组织的分析揭示了DYT 1脑中eIF 2 α和Akt/mTOR翻译控制途径的失调，这一发现在第二个啮齿动物模型和人脑中得到了证实。最后，一个公正的蛋白质组学分析确定了相关的变化，神经元蛋白质景观表明异常ER蛋白质代谢和钙失调。功能研究证实了DYT 1基因型和神经元钙动力学之间的相互作用。总的来说，这些发现推进了我们对肌张力障碍的认识，将翻译控制途径和钙生理学与肌张力障碍发病机制联系起来，并确定了潜在的新药理学靶点。
Dystonia type 1 (DYT1) is a dominantly inherited neurological disease caused by mutations in TOR1A, the gene encoding the endoplasmic reticulum (ER)-resident protein torsinA. Previous work mostly completed in cell-based systems suggests that mutant torsinA alters protein processing in the secretory pathway. We hypothesized that inducing ER stress in the mammalian brain in vivo would trigger or exacerbate mutant torsinA-induced dysfunction. To test this hypothesis, we crossed DYT1 knock-in with p58(IPK)-null mice. The ER co-chaperone p58(IPK) interacts with BiP and assists in protein maturation by helping to fold ER cargo. Its deletion increases the cellular sensitivity to ER stress. We found a lower generation of DYT1 knock-in/p58 knock-out mice than expected from this cross, suggesting a developmental interaction that influences viability. However, surviving animals did not exhibit abnormal motor function. Analysis of brain tissue uncovered dysregulation of eiF2 alpha and Akt/mTOR translational control pathways in the DYT1 brain, a finding confirmed in a second rodent model and in human brain. Finally, an unbiased proteomic analysis identified relevant changes in the neuronal protein landscape suggesting abnormal ER protein metabolism and calcium dysregulation. Functional studies confirmed the interaction between the DYT1 genotype and neuronal calcium dynamics. Overall, these findings advance our knowledge on dystonia, linking translational control pathways and calcium physiology to dystonia pathogenesis and identifying potential new pharmacological targets.