Investigating how the microbiota modulates neuroinflammatory signaling and neurodegeneration in Parkinson's disease and dementia

帕金森病(PD)和路易体痴呆(DLB)是涉及基因突变的复杂疾病。 导致α-突触核蛋白(a-突触核蛋白聚集)的环境相互作用。最近的调查表明， 肠道微生物组可以调节神经炎性反应，以标记a-突触核蛋白聚集，但几乎没有 了解特定的肠道微生物介体。研究遗传性神经变性的罕见家系 事实证明，这种与散发性疾病非常相似的疾病对该领域来说是无价的，为理解特发性提供了一个窗口。 疾病在更受控制的遗传和环境背景下。我们正在调查环境问题 利用来自这样一个含有α-α基因的家庭的微生物组样本来确定疾病外显性的决定因素 突触核蛋白(a-突触核蛋白)E46和GT；K突变，并表现出一系列临床帕金森病痴呆(PDD)/DLB结果， 在病理上模仿这些疾病的零星形式。我们假设肠道微生物区系对 通过分泌影响神经炎性反应的代谢物来促进PDD/DLB的发展 信号和神经功能。在我们的初步数据中，我们首先确定了特定的细菌物种 与PDD/DLB病外显性有关，其中一些先前已被报道在 警察。第二，我们发现将PDD/DLB肠道微生物区系转移到PD小鼠模型中(带有扩增的E46和K； 突变)增加了运动和认知缺陷。第三，PDD/DLB微生物群转移改变的小胶质细胞 转录图谱表明微生物区系的变化可能通过以下途径促进疾病的发生 神经免疫调节。在这项提案中，我们的目标是识别与以下物质有关的微生物和代谢物 利用体内模型研究PDD/DLB的发病机制，并评估这些代谢物是否直接影响小胶质细胞 PDD/DLB诱导的多能干细胞来源的体外培养中的功能和神经元存活。第一, 为了研究与运动和认知功能改变相关的潜在的肠-脑轴机制，我们将 确定肠道元基因组和代谢物的变化，分析改变的小胶质细胞转录图谱和 评估PDD/DLB-微生物区系定植小鼠的α-突触核蛋白病理学，与定植 健康对照或中枢神经系统无症状E46K载体微生物组。第二，确定 微生物代谢产物参与PDD/DLB的通路，我们将治疗E46K PDD/DLB患者和基因 用室内分离的细菌上清液校正IPSC来源的小胶质细胞和神经元 E46K PDD/DLB个体中有丰富的微生物种类，或来自细菌敏化小胶质细胞的培养液。我们会 评估神经炎性细胞因子和趋化因子谱、小胶质细胞转录谱、轴突 生长和存活，以及α-突触核蛋白病理以确定PDD/DLB微生物的机制影响 代谢物对体外可变疾病外显率的影响。所获得的知识和建立的模型体系 这一R21提议可能最终有助于理解分子和代谢功能 为今后的机制研究提供必要的生物资源。

Parkinson’s disease (PD) and dementia with Lewy bodies (DLB) are complex diseases involving gene- environment interplay that lead to alpha-synuclein (a-synuclein aggregation). Recent investigations suggest that the gut microbiome can modulate neuroinflammatory responses to hallmark a-synuclein aggregation, but little is known about specific gut microbial mediators. Studying rare kindreds with inherited forms of neurodegeneration that closely mimic sporadic disease has proved invaluable to the field, offering a window to understand idiopathic disease in a more controlled genetic and environmental background. We are investigating environmental determinants of disease penetrance utilizing microbiome samples from such a family harboring an alpha- synuclein (a-synuclein) E46>K mutation and exhibiting a spectrum of clinical PD dementia (PDD)/DLB outcomes, that pathologically mimic sporadic forms of these diseases. We hypothesize that gut microbiota contributes to the development of PDD/DLB through the secretion of metabolites that affect neuroinflammatory signaling and neuronal function. In our preliminary data, first we identified specific bacterial species associated with PDD/DLB disease penetrance, some of which have been previously reported to be altered in PD. Second, we found that transfer of the PDD/DLB gut microbiota into a PD mouse model (with amplified E46>K mutation) enhanced motor and cognitive deficits. Third, PDD/DLB microbiome transfer altered microglial transcriptional profiles suggesting that changes in microbiota could contribute to disease pathogenesis through neuroimmune modulation. In this proposal, we aim to identify microbes and metabolites which are linked with PDD/DLB pathogenesis using in vivo models and evaluate whether these metabolites directly affect microglial function and neuronal survival in vitro in PDD/DLB induced pluripotent stem cell (iPSC)-derived cultures. First, to investigate potential gut-brain axis mechanisms associated with altered motor and cognitive function, we will identify changes in the gut metagenome and metabolites, analyze altered microglia transcriptional profiles and evaluate a-synuclein pathology in PDD/DLB-microbiota colonized mice, when compared to mice colonized with either healthy control or CNS asymptomatic E46K carrier microbiome. Second, to determine the impact of microbial metabolites on pathways involved in PDD/DLB, we will treat E46K PDD/DLB patient and gene corrected iPSC-derived microglia and neuronal cultures with either bacterial supernatants from in-house isolated microbial species abundant in E46K PDD/DLB individuals, or media from bacteria-sensitized microglia. We will evaluate the neuroinflammatory cytokine and chemokine profile, microglia transcriptional profiles, neurite outgrowth and survival, and a-synuclein pathology to determine the mechanistic impact of PDD/DLB microbial metabolites on variable disease penetrance in vitro. The knowledge gained and model systems established in this R21 proposal may ultimately contribute to the understanding of molecular and metabolic functions that affect PD and PD dementia and provide essential biologic resources for future mechanistic study.