Mitochondrial protection of a GDNF propeptide

描述(由申请人提供)：线粒体功能障碍已被确认为帕金森病(PD)发病机制中的关键角色之一。虽然大多数病例的病因尚不清楚，但在暴露于各种环境和职业毒素的患者中，已显示出进行性帕金森症状的发展。大量研究表明，这些神经毒素特异性地抑制多巴胺能神经元的线粒体呼吸链复合体，从而启动一系列事件，最终导致细胞死亡。此外，老年人神经系统对环境神经毒素的敏感性增加。因此，对于帕金森病和帕金森症状的长期治疗，治疗策略不仅需要恢复多巴胺能神经元的功能，还需要提供线粒体保护和恢复，以抵御各种应激，包括环境毒素暴露。在过去，神经营养生长因子作为神经疾病的潜在治疗药物受到了相当大的关注。然而，这些天然分子的临床应用并没有取得进展，主要是因为药理上的缺点和直接将大蛋白分子输送到大脑的挑战。来自神经营养因子家族的生理功能前肽的出现为生物治疗的探索和评估提供了丰富的新的、更小的序列。对胶质细胞系衍生神经营养因子(GDNF)前序列的检测预测，内部二碱性内肽酶位点将产生较小的胺化11个氨基酸残基，称为多巴胺神经元刺激肽-11(DNSP-11)。最近的评估表明，DNSP-11在正常大鼠和帕金森病大鼠模型中表现出类似的GDNF样神经营养反应。然而，细胞培养和蛋白质组学下拉数据表明，DNSP-11与成熟的胶质细胞源性神经营养因子的功能不同，从而导致我们假设DNSP-11‘S的神经生物学作用是通过线粒体实现的。目前提案中概述的研究将测量DNSP-11‘S在MN9D多巴胺能细胞系中针对线粒体呼吸复合体的毒素的生物能量和保护作用。本研究获得的信息将进一步加深我们对该前肽的神经生物学活性的了解，并为未来DNSP-11的评价和生物治疗开发提供依据。 公共卫生相关性：帕金森氏病(PD)是一种慢性神经系统疾病，影响着100多万美国人，其特征是弯腰、平衡障碍、僵硬、静止性手震和运动迟缓。虽然帕金森病的原因在很大程度上尚不清楚，但帕金森症状已被证明是在长期接触常见的环境毒素后出现的，这些毒素专门针对多巴胺神经元的线粒体。该试点项目的目的是从线粒体特异性毒素中研究一种新的神经营养前肽DNSP-11的神经保护特性，为其作为潜在的帕金森病治疗药物的下游评估铺平道路。

DESCRIPTION (provided by applicant): Mitochondrial dysfunction has been identified as one of the key players in Parkinson's disease (PD) pathogenesis. While the etiology is unknown in most cases, the development of progressive parkinsonian symptoms has been shown in patients following exposure to various environmental and occupational toxins. Numerous studies demonstrate that these neurotoxins specifically inhibit the mitochondrial respiratory chain complexes of dopaminergic neurons, which initiates a cascade of events ultimately leading to cell death. Furthermore, the susceptibility to environmental neurotoxins is increased in the aged nervous system. Thus for the long-term treatment of PD and parkinsonian symptoms, therapeutic strategies are needed that not only restore dopaminergic neuron function, but also provide mitochondrial protection and restoration from various stresses, including environmental toxin exposure. In the past, neurotrophic growth factors have received considerable attention as potential therapeutic agents for neurological disorders. However, the clinical application of these native molecules has not advanced primarily due to pharmacological disadvantages and challenges associated with directly delivering large protein molecules to the brain. The emergence of physiologically functional propeptides from the neurotrophic factor family provides a wealth of novel, smaller sequences for biotherapeutic exploration and evaluation. Examination of the glial cell line-derived neurotrophic factor (GDNF) prosequence predicts internal dibasic endopeptidase sites that would yield a smaller, amidated eleven amino acid residue peptide named dopamine neuron stimulating peptide-11 (DNSP-11). Recent evaluation of DNSP-11 has shown that it exhibits similar GDNF-like neurotrophic responses in normal and parkinsonian rat models. However, cell culture and proteomic pull-down data suggest that DNSP-11 functions differently than mature GDNF; leading to our hypothesis that DNSP-11's neurobiological actions are through the mitochondria. The research outlined in the current proposal will measure DNSP-11's bioenergetic and protective effects, in the MN9D dopaminergic cell line, from toxins that specifically target the mitochondrial respiratory complexes. The information obtained in this study will further our understanding of this propeptide's neurobiological activity and provide the basis for future evaluation and biotherapeutic development of DNSP-11. PUBLIC HEALTH RELEVANCE: Parkinson's disease (PD), a chronic neurological disorder that affects over 1 million Americans, is characterized by stooped posture, balance impairments, rigidity, resting hand tremors, and bradykinesia. While the cause of PD is largely unknown, parkinsonian symptoms have been shown to develop following long-term exposure to common environmental toxins that specifically target the mitochondria of dopamine neurons. The goal of this pilot project is to investigate the neuroprotective properties of a novel neurotrophic propeptide, DNSP-11, from mitochondrial-specific toxins to pave the way for its downstream evaluation as a potential PD therapeutic.