Mitochondrial protection of a GDNF propeptide

描述（由申请人提供）：线粒体功能障碍已被确定为帕金森病（PD）发病机制的关键因素之一。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后，患者会出现进行性帕金森病症状。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物，从而引发一系列事件，最终导致细胞死亡。此外，老年神经系统对环境神经毒素的易感性增加。因此，对于帕金森病和帕金森症状的长期治疗，需要的治疗策略不仅要恢复多巴胺能神经元的功能，还要提供线粒体保护和恢复各种应激，包括环境毒素暴露。在过去，神经营养生长因子作为神经系统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，主要是由于药理学上的缺点和直接将大蛋白分子递送到大脑的挑战。神经营养因子家族中具有生理功能的前肽的出现为生物治疗的探索和评估提供了丰富的新颖、较小的序列。对神经胶质细胞系来源的神经营养因子（GDNF）序列的检查预测了内部双碱性内肽酶位点，该位点将产生一个较小的、经过修饰的11个氨基酸残基肽，名为多巴胺神经元刺激肽-11 （DNSP-11）。最近对DNSP-11的评估表明，它在正常和帕金森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的功能不同于成熟的GDNF；这导致我们的假设，即DNSP-11的神经生物学作用是通过线粒体进行的。当前提案中概述的研究将测量DNSP-11的生物能量和保护作用，在MN9D多巴胺能细胞系中，针对专门针对线粒体呼吸复合物的毒素。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认识，并为今后DNSP-11的评价和生物治疗开发提供依据。

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.