Isolating small-molecule enhancers of HtrA1, an alpha-synuclein disaggregase

项目总结 在帕金森病(PD)中，蛋白平衡网络无法对抗-突触核蛋白(-SYN)的错误折叠。- SYN形成可引发和传播疾病的可溶性有毒寡聚体和自模板化淀粉样蛋白纤维 诺沃。-Syn纤维聚集成大的胞浆内含物，称为路易小体，这是帕金森病的病理特征。 人的分子伴侣、热休克蛋白110、热休克蛋白70和热休克蛋白40可以解聚-SYN纤维并减少其 毒性。这些发现与我们在HSP104和增强变异体方面的进展一起表明，-SYN 齐聚物和纤维并不难处理，但可以迅速分解成无毒的形式。最近，一个 第二个人类蛋白解聚酶HtrA1被发现能够分解和降解tau和 淀粉样β纤维。HTRA1是一种存在于细胞质中的伴侣和同源寡聚体PDZ丝氨酸蛋白酶 以及细胞外空间，它选择性地降解错误折叠的底物，而不影响折叠的底物。 我们未发表的数据表明，htrA1挽救了酵母中的-SYN毒性，并分解和降解了- 体外培养的SYN纤维。我们假设HtrA1解聚酶活性的小分子增强剂可能 刺激消除帕金森病患者变性神经元中有害的-SYN积聚。因此， 我们认为，HtrA1出人意料的蛋白解聚酶活性代表了一种有前途的、新的PD- 相关目标。我们假设用特定的药物增强HtrA1解聚酶的活性 小分子将使有毒的寡聚体和淀粉样蛋白形式的- SYN，并赋予帕金森病的治疗益处。因此，我们将追求两个具体目标：(1)隔离小 增强-SYN解聚酶活性的分子；以及(2)评估小分子的能力 HtrA1解聚酶活性增强剂挽救-SYN在哺乳动物原代体内的聚集和毒性 帕金森病的神经元模型。到这个项目结束时，将会有一个关于移动一个小的- HtrA1的分子增强子进入啮齿动物模型并最终进入帕金森病患者。小分子刺激作用 HTRA1解聚酶活性可消除多巴胺能神经元中有害的-SYN错误折叠 并为帕金森病提供了一种改变游戏规则的解决方案。重要的是，HtrA1的小分子增强剂 解聚酶活性在其他神经退行性疾病中也可能有重要的应用 有害的蛋白质错误折叠，包括阿尔茨海默病和额颞痴呆。

Project summary In Parkinson's Disease (PD), the proteostasis network fails to counter the misfolding of -synuclein (-syn). - Syn forms soluble toxic oligomers and self-templating amyloid fibrils that can initiate and propagate disease de novo. -Syn fibrils cluster into large cytoplasmic inclusions termed Lewy Bodies, a pathological hallmark of PD. Human molecular chaperones, Hsp110, Hsp70, and Hsp40 can disaggregate -syn fibrils and reduce their toxicity. These findings together with our advances with Hsp104 and potentiated variants suggest that -syn oligomers and fibrils are not intractable but can be rapidly disassembled into non-toxic forms. More recently, a second human protein disaggregase, HtrA1, has been discovered that disassembles and degrades tau and amyloid-beta fibrils. HtrA1 is a chaperone and homo-oligomeric PDZ serine protease found in the cytoplasm and extracellular space, which selectively degrades misfolded substrates while leaving folded substrates alone. Our unpublished data suggest that HtrA1 rescues -syn toxicity in yeast, and, disassembles and degrades - syn fibrils in vitro. We hypothesize that small-molecule enhancers of HtrA1 disaggregase activity could stimulate the elimination of deleterious -syn accumulations in the degenerating neurons of PD patients. Thus, we propose that the unanticipated protein disaggregase activity of HtrA1 represents a promising, novel PD- relevant target. We hypothesize that enhancing the activity of HtrA1 disaggregase activity with specific small molecules will enable dissolution and degradation of toxic oligomeric and amyloid forms of - syn, and confer therapeutic benefits in PD. Thus, we will pursue two specific aims: (1) Isolate small molecules that enhance the -syn disaggregase activity of HtrA1; and (2) Assess the ability of small-molecule enhancers of HtrA1 disaggregase activity to rescue -syn aggregation and toxicity in mammalian primary neuron models of PD. By the end of this project, there will be a clear “go/no go” decision for moving a small- molecule enhancer of HtrA1 into rodent models and ultimately PD patients. Small-molecule stimulation of HtrA1 disaggregase activity could eliminate deleterious -syn misfolding in degenerating dopaminergic neurons and provide a game-changing solution for PD. Importantly, small-molecule enhancers of HtrA1 disaggregase activity may also have important applications in other neurodegenerative disorders caused by deleterious protein misfolding, including Alzheimer's disease and frontotemporal dementia.