Investigating cell type specific defects in protein quality control across the genetic landscape of Parkinson’s disease

帕金森病（PD）是第二常见的进行性神经退行性疾病。目前还没有治愈方法，只能对运动症状进行短暂的对症治疗。如果我们想要在PD的早期阶段解决它并减缓它的发展，就迫切需要创新的治疗方法来改变神经元死亡之前的早期非运动症状。不幸的是，由于对早期神经元缺陷起源的认识不足，这一工作受到了阻碍。在这个研究项目中，我将解决这一知识缺口，以获得对PD早期受影响的分子途径的重要见解。有20多个基因与家族性帕金森病有关。大多数“PD基因”参与蛋白质质量控制的各个方面，但尚不清楚这些不同的分子缺陷最终如何在重叠病理中表现出来。黑腹果蝇是研究神经退行性疾病的优秀模式生物，因为70%的人类疾病基因在果蝇中保守，PD病理的关键特征包括睡眠障碍或嗅觉受损等早期症状。有趣的是，一些PD蝇模型在幼龄动物大脑的相同细胞类型中表现出类似的转录组变化。这些失调基因主要影响蛋白质稳态通路，在受影响最严重的细胞类型中，可以通过增加突触的蛋白质周转能力来挽救神经元功能障碍。因此，我推测不同的致病性PD变异通常会聚到一个共同的中心枢纽，该枢纽在疾病早期解除突触前末端的蛋白质质量控制通路，这有助于神经元死亡之前的神经元功能障碍。在拟议的项目中，我将通过采购包含所有已知致病性PD突变的独特果蝇集合来调查这一假设。我将评估PD突变如何影响突触末端的细胞蛋白稳态网络，包括全局和局部。我将通过结合多用途苍蝇遗传学和生物化学分析以及最先进的单细胞RNA测序来确定常见的脆弱性途径。随后，我将验证PD患者诱导多能干细胞衍生神经元中携带相应突变的中心枢纽和机制。因此，我将在PD的家族遗传空间中确定在疾病早期解除调控的细胞类型特异性易感性途径中的共同关键因素。通过研究家族性帕金森病的分子机制，我也将对散发性帕金森病的病因有新的认识。如果成功，该项目将带来三个重要成果：我将获得创新的治疗靶点来改变疾病的进展。2. 我将揭示蛋白质稳态如何维持突触功能和2。回答为什么这个过程在PD早期受到影响。

Parkinson’s disease (PD) is the second most common progressive neurodegenerative disorder. There is currently no cure, and only transient symptomatic treatments of the motor symptoms are available. If we want to tackle PD in its earliest stages and slow its progression, there is an urgent need for innovative therapeutics that modify the earliest non-motor symptoms that precede neuronal death. Unfortunately, this is hampered by insufficient knowledge on the origins of early neuronal defects. In this research project, I will address this knowledge gap to gain important insights into the molecular pathways, which are affected early in PD.More than 20 genes have been linked to familial forms of PD. Most “PD genes” are involved in various aspects of protein quality control, but it remains unclear how these diverse molecular defects ultimately manifest in an overlapping pathology.Drosophila melanogaster is an excellent model organism for studying neurodegenerative diseases as 70% of human disease genes are conserved in flies, and key features of PD pathology are recapitulated including early symptoms such as sleep disorders or impaired sense of smell.Intriguingly, a few PD fly models exhibit similar transcriptome changes in the same cell types in the brains of young animals. These deregulated genes mainly affect protein homeostasis pathways and neuronal dysfunction can be rescued by increasing the protein turnover capacity at synapses in the most affected cell types.Therefore, I speculate that different pathogenic PD variants generally converge onto a common central hub that deregulates protein quality control pathways in the presynaptic terminal early in the disease and that this contributes to the neuronal dysfunction that precedes neuronal death.In the proposed project, I will investigate this hypothesis by sourcing a unique Drosophila collection containing all known pathogenic PD mutations. I will assess how the PD mutations affect the cellular protein homeostasis network, both globally and locally, in synaptic terminals. I will determine common vulnerability pathways by combining versatile fly genetics and biochemical assays with state-of-the-art single cell RNA sequencing. Subsequently, I will validate the identified central hubs and mechanisms in induced pluripotent stem cell derived neurons from PD patients harboring the corresponding mutations.Thus, I will identify the common key factors in the cell type specific vulnerability pathways that are deregulated early in disease across the familial genetic space of PD. By studying the molecular mechanisms underlying familial PD, I will also gain novel insights into the etiology of sporadic PD.If successful, this project will deliver three important results: 1. I will obtain innovative therapeutic targets to modify disease progression. 2. I will reveal how protein homeostasis maintains synaptic function and 3. answer why this process is affected early in PD.