Novel DNA damage-Based Mechanisms and Therapeutics for Parkinson’s disease

帕金森病（PD）是一种常见的破坏性神经退行性疾病， 美国有1000万人，全球有1000万人或更多。目前，没有治疗干预措施， 阻止或减缓帕金森病的进展已经提出了几种假说作为PD的病因， 包括多巴胺能神经元丢失、线粒体功能障碍、氧化应激和α-突触核蛋白 沉积（路易体），但PD的确切原因仍不清楚。最近的研究表明， 核DNA损伤，特别是核DNA双链断裂（DNA DSB）， 包括PD在内的广谱人类神经退行性疾病中神经元损失的进展。 然而，尚不清楚核DNA DSB 1）是否作为PD的主要驱动因素或仅仅伴随发生， 与疾病进展，和2）赋予PD发展的额外风险因素。虽然DNA的作用 DSB在神经系统疾病中的研究相当充分，其参与神经变性的机制 以及PD条件下的行为缺陷是未知的。这代表了我们知识上的一个缺口， 建议研究解决。为了确定DNA DSB在PD中的作用，我们已经产生并表征了一个 新型小鼠模型系统。我们以前已经证明，CDKN 1A相互作用锌缺乏， 指状蛋白1（CIZ 1）是一种核蛋白，在辐射小鼠中导致持续的DNA双链断裂和细胞死亡 胚胎成纤维细胞老年CIZ 1 KO小鼠的大脑显示出明显和持续的DNA DSB， 压力和细胞死亡，所有这些都在PD中发现。此外，我们的初步调查结果表明， 在帕金森病患者和PD小鼠模型的大脑中，DNA DSB升高，CIZ 1水平降低。 我们的中心假设是，大脑中细胞核DNA双链断裂的积累增加有助于 神经变性和行为缺陷，DNA修复在帕金森病小鼠中起着关键作用。 减轻PD的病理后果。本申请的目的是1）理解 核DNA DSB在PD发病机制中的作用以及它们如何与多巴胺能神经元的损失相关; 2） 测试DNA修复激活剂在缓解PD后神经病理学症状中的治疗益处。我们 提出两个具体目标来检验我们的假设。在目标1中，我们将定义DNA的作用和机制 DSB在小鼠模型神经变性和行为功能障碍进展中的作用 PD的主要特征。在目标2中，我们将确定DNA修复激活剂的治疗益处， 抑制PD小鼠模型中DNA损伤介导的神经变性和行为缺陷。我们 该提案有望确定DNA DSB在PD中的潜在作用，并确定治疗方案。 靶向DNA损伤反应在减轻PD病理后果中的益处。

Parkinson’s disease (PD) is a common and devastating neurodegenerative disorder that affects up to one million individuals in the US and 10 million or more worldwide. Currently, there are no therapeutic interventions that stop or slow the progression of PD. Several hypotheses have been proposed as causative of PD, including, loss of dopaminergic neurons, mitochondrial dysfunction, oxidative stress, and α-synuclein deposition (Lewy bodies), but the exact causes of PD are still unclear. More recent studies have highlighted the role of nuclear DNA damage, particularly, nuclear DNA double-strand breaks (DNA DSBs), in the progression of neuronal loss in a broad spectrum of human neurodegenerative diseases including PD. However, it is not clear if nuclear DNA DSBs 1) serve as a primary driver of PD or simply occur concomitant with disease progression, and 2) confer an additional risk factor for PD development. Although, a role of DNA DSBs in neurological disorders is fairly-well studied, the mechanisms of its involvement in neurodegeneration and behavioral deficits during PD conditions are unknown. This represents a gap in our knowledge, which this proposed study will address. To define the role of DNA DSBs in PD, we have generated and characterized a novel mouse model system. We have previously demonstrated that a deficiency of CDKN1A-interacting zinc finger protein 1 (CIZ1), a nuclear protein, leads to sustained DNA DSBs, and cell death in irradiated mouse embryonic fibroblasts. The brains of aged CIZ1KO mice show overt and sustained DNA DSBs, oxidative stress, and cell death, all of which are found in PD. Furthermore, our preliminary findings demonstrated, elevated DNA DSBs and reduced CIZ1 levels in the brains of Parkinson’s patients and mouse model of PD. Our central hypothesis is that the increased accumulation of nuclear DNA DSBs in the brain contributes to neurodegeneration and behavioral deficits in Parkinsonian mice and that DNA repair plays a critical role in alleviating the pathological consequences in PD. The objectives of this application are 1) to understand the role of nuclear DNA DSBs in PD pathogenesis and how they relate to the loss of dopaminergic neurons and 2) to test the therapeutic benefits of DNA repair activators in alleviating post-PD neuropathological symptoms. We propose two specific aims to test our hypothesis. In Aim 1, we will define the role and mechanisms of DNA DSBs in the progression of neurodegeneration and behavioral dysfunction in a mouse model that recapitulates key features of PD. In Aim 2, we will determine the therapeutic benefits of DNA repair activators to effectively suppress DNA damage-mediated neurodegeneration and behavioral deficit in mouse models of PD. Our proposal is expected to identify the potential contribution of DNA DSBs in PD and determine the therapeutic benefits of targeting the DNA damage response in alleviating the pathological consequences in PD.