Guanabenz in the treatment of mutant SOD1 ALS mice

描述(申请人提供)：我们计划的研究可能为肌萎缩侧索硬化症(ALS)提供新的靶点和治疗方向，ALS是一种无法治愈的致命疾病。突变(Mt)SOD1被认为是导致家族性肌萎缩侧索硬化症(FALS)的原因，因为功能增强可能涉及蛋白质的错误折叠。我们最近发表的数据表明，PERK(作为未折叠蛋白反应[UPR]的一部分，导致eIF2？的磷酸化，并随后抑制翻译)的单倍性不足会加速G85R mtSOD1FALS转基因小鼠的疾病，并且有初步的未发表的数据表明，Gadd34的敲除(去磷酸化eIF2？)可以改善疾病。这些数据导致了这一提议背后的假设：PERK和PERK途径的增强将改善疾病。在特定的目标I中，我们将测试FDA批准的药物guanabenz在改善G85R mtSOD1FALS小鼠疾病方面的有效性。先前的研究表明，愈那苯能促进组织培养细胞中PrPsc(一种错误折叠的蛋白质)的清除，还能显著延长PrPsc转基因小鼠的存活时间。Ganabenz最近被发现与蛋白磷酸酶1的一个调节亚基PPP1R15A/Gadd34结合，选择性地破坏应激诱导的eIF2的去磷酸化。Ganabenz是一种特别有吸引力的治疗FALS的药物，因为人们对它的药代动力学(例如，已知它可以穿越血脑屏障)和安全性已知很多，因为它目前用作抗高血压药物。在特定的目标II中，我们计划在应激反应被触发之前激活PERK，并在内质网应激期间(例如，在疾病期间)将PERK提高到高于正常内源性水平。我们将使用腺相关病毒9(AAV9)来传递Fv2E-PERK，它包含PERK的激活域(通常通过二聚化激活)与蛋白质模块融合。即使在没有应激反应的情况下，给予小二聚体分子(AP20187)也会导致PERK激活。我们的研究结果将对散发性ALS以及FAL产生影响，因为：最近的数据表明，散发性ALS也可能涉及SOD1蛋白或其活性的异常；TDP-43与散发性ALS和FAL有关，具有潜在的与UPR的相互作用，因为TDP-43在这些疾病中错误折叠，并且因为TDP-43是应激颗粒的组成部分-这可能是UPR的结果。

DESCRIPTION (provided by applicant): Our planned studies may provide new targets and treatment directions in amyotrophic lateral sclerosis (ALS), a fatal disease with no cure. Mutant (mt) SOD1 is thought to cause familial ALS (FALS) because of a gain in function probably involving misfolding of the protein. We recently published data that show that haploinsufficiency of PERK (which as part of the unfolded protein response [UPR] leads to phosphorylation of eIF2¿ with a subsequent suppression of translation) accelerates disease in G85R mtSOD1 FALS transgenic mice and have preliminary unpublished data that show that a knockdown of GADD34 (which dephosphorylates eIF2¿) ameliorates disease. These data have led to the hypothesis underlying this proposal: an enhancement of PERK and the PERK pathway will ameliorate disease. In Specific Aim I, we will test the efficacy of an FDA-approved drug, guanabenz, in ameliorating disease in G85R mtSOD1 FALS mice. Guanabenz was previously shown to promote clearance of scrapie prion protein (PrPsc) (a misfolded protein) in tissue-culture cells and also to significantly prolong survival of PrPsc transgenic mice. Guanabenz was very recently found to bind to a regulatory subunit of protein phosphatase 1, PPP1R15A/GADD34, selectively disrupting the stress-induced dephosphorylation of eIF2¿. Guanabenz is an especially attractive drug for the treatment of FALS because a great deal is known about its pharmacokinetics (e.g., it is known to cross the blood-brain barrier) and safety due to its present use as an antihypertensive. In Specific Aim II, we plan to activate PERK before the stress response is triggered, and also enhance PERK above the normal endogenous levels during ER stress (e.g., during disease). We will use adeno-associated virus9 (AAV9) to deliver Fv2E-PERK, which contains the kinase domain of PERK (that is normally activated by dimerization) fused to a protein module. Administration of a small dimerizer molecule (AP20187) leads to PERK activation, even in the absence of a stress response. The results of our studies will have implications for sporadic ALS as well as FALS because: recent data suggest that sporadic ALS may also involve abnormalities in the SOD1 protein or its activity; TDP-43, which is implicated in sporadic ALS and FALS, has potential interactions with the UPR since TDP-43 is misfolded in these diseases and because TDP-43 is a constituent of stress granules-which can form as a result of the UPR.