Guanabenz in the treatment of mutant SOD1 ALS mice

描述（由申请人提供）：我们计划的研究可能为肌萎缩性侧索硬化症（ALS）这一无法治愈的致命疾病提供新的靶点和治疗方向。突变（mt） SOD1被认为引起家族性ALS (FALS)，因为可能涉及蛋白质错误折叠的功能获得。我们最近发表的数据表明，PERK的单倍不足（作为未折叠蛋白反应[UPR]的一部分导致eIF2¿磷酸化并随后抑制翻译）加速了G85R mtSOD1 FALS转基因小鼠的疾病，并且有初步未发表的数据表明，敲低GADD34（使eIF2¿去磷酸化）可以改善疾病。这些数据导致了这一提议的假设：PERK和PERK途径的增强将改善疾病。在Specific Aim I中，我们将测试fda批准的药物guanabenz在改善G85R mtSOD1 FALS小鼠疾病方面的功效。先前的研究表明，瓜纳苯能促进组织培养细胞中瘙痒朊蛋白（PrPsc）（一种错误折叠的蛋白）的清除，并能显著延长PrPsc转基因小鼠的存活时间。最近发现Guanabenz与蛋白磷酸酶1的调控亚基PPP1R15A/GADD34结合，选择性地破坏应激诱导的eIF2¿的去磷酸化。瓜纳苯钠是治疗FALS的一种特别有吸引力的药物，因为人们对它的药代动力学（例如，已知它能穿过血脑屏障）和目前用作抗高血压药物的安全性了解很多。在Specific Aim II中，我们计划在应激反应触发之前激活PERK，并在内质网应激（例如疾病期间）期间将PERK提高到正常内源性水平以上。我们将使用腺相关病毒9 （AAV9）传递Fv2E-PERK，它包含PERK的激酶结构域（通常通过二聚化激活）融合到蛋白质模块上。即使在没有应激反应的情况下，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和FALS具有启示意义，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FALS有关，由于TDP-43在这些疾病中错误折叠，并且TDP-43是压力颗粒的一个组成部分，因此可能与UPR存在潜在的相互作用。

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a subsequent suppression of translation) accelerates disease in G85R mtSOD1 FALS transgenic mice and have preliminary unpublished data that show that a knockdown of GADD34 (which dephosphorylates eIF2¿) ameliorates disease.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.