Novel roles of VGLUT in sex differences in dopamine neuron vulnerability to environmental toxicant-induced neurodegeneration

VGLUT 在多巴胺神经元易受环境毒物诱导的神经变性的性别差异中的新作用

• 批准号: 10582080
• 负责人: ZACHARY FREYBERG
• 金额: $ 47.43万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-06 至 2027-12-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10582080
• 关键词: Age; Aging; Autopsy; Biogenesis; Biological Markers; Brain; Cytoplasm; Data; Disease model; Dopamine; Dose; Drosophila genus; Environmental Monitoring; Exposure to; Female; Genes; Genetic; Genetic Transcription; Glutamate Transporter; Glutathione; Human; Imaging Device; Injury; Knock-out; Link; Mammals; Mediating; Midbrain structure; Mitochondria; Nerve Degeneration; Neuronal Injury; Neurotoxins; Orthologous Gene; Paraquat; Parkinson Disease; Pathway interactions; Patients; Pesticides; Rattus; Reactive Oxygen Species; Recycling; Regulation; Risk; Rodent; Rodent Model; Role; Rotenone; Sex Differences; Substantia nigra structure; Testing; Toxic Environmental Substances; Toxicant exposure; Translating; Translational Regulation; Vesicle; Woman; alpha synuclein; brain tissue; cohort; comparative; disorder control; dopaminergic neuron; effective therapy; exposed human population; female sex hormone; fly; insight; knock-down; male; men; mitochondrial metabolism; neuron loss; neuronal survival; neuroprotection; novel; overexpression; pesticide exposure; resilience; response; sex; sexual dimorphism; toxicant; transcriptome sequencing

PROJECT SUMMARY Exposure to environmental toxicants including pesticides causes dopamine (DA) neuron loss in the substantia nigra (SN) and raises risk for developing Parkinson’s disease (PD). Toxicant exposure studies show sexually dimorphic DA neuron resilience, such that females lose fewer DA neurons than males. This sex difference is relevant since PD in women is less prevalent and has a later age of symptomatic onset. However, the mechanisms for these sex differences in DA neuron resilience to toxicants remain poorly understood. We have leveraged the respective advantages of fly and rodent models of DA neurodegeneration to provide new insights into toxicants’ effects on selective DA neuron resilience, which we have translated to human postmortem brain tissue from PD patients. We identified the vesicular glutamate transporter VGLUT2 in mammals and its Drosophila ortholog dVGLUT as modulators of sex differences in DA neuron resilience. We find: 1) dVGLUT/VGLUT2+ DA neurons are likelier to survive insults versus DA neurons that do not express the transporter; 2) Conditional dVGLUT/VGLUT2 knockout in DA neurons increases vulnerability to insults; and 3) dVGLUT/VGLUT2 expression is upregulated in surviving DA neurons in response to PD-linked insults including aging, misfolded a-synuclein, and neurotoxins. Furthermore, we discovered females express more dVGLUT/VGLUT2 in DA neurons compared to males – a finding conserved across flies, rodents and humans that may explain the sex differences in PD. Yet, whether sex differences in DA neuron VGLUT2 expression contribute to resilience to environmental toxicants like rotenone and paraquat remains unknown. Thus, we hypothesize DA neuron dVGLUT/VGLUT2 expression is part of a conserved, sexually dimorphic neuroprotective response to DA neuron injury by environmental toxicants in PD. To test our hypothesis, we developed comparative approaches across flies, rodents and postmortem human brain, along with new genetic and imaging tools, to determine whether VGLUT2 modulates sex differences in DA neuron resilience to the pesticide rotenone (Aim 1). We will also determine the mechanisms for dVGLUT- and VGLUT2-mediated resilience to pesticides in males and females (Aim 2). Lastly, we will determine DA neuron VGLUT2 expression in brains of male and female PD patients, including in brains of subjects with known exposure to the pesticide heptachlor (Aim 3). Identifying VGLUT2’s roles in sex differences in DA neuron resilience as a result of environmental toxicant exposure may provide new insights into PD. Moreover, determining the mechanisms of increased DA neuron resilience in females can be transferred to males to boost DA neuron survival in PD. This may ultimately lead to new, effective treatments to either slow or stop PD neurodegeneration in both men and women.

项目摘要 暴露于包括农药在内的环境有毒物质会导致多巴胺（DA）神经元丧失 Nigra（SN）并增加了发展帕金森氏病（PD）的风险。毒物暴露研究表明性 二态DA神经元的弹性，使女性失去的DA神经元比男性少。这种性别差异是 相关，因为女性的PD较不流行，并且有症状的发作年龄。但是， DA神经元对有毒物质的弹性的这些性别差异的机制仍然很少理解。我们有 利用DA神经变性的苍蝇和啮齿动物模型的相对优势提供了新的见解 进入有毒物质对选择性DA神经元的弹性的影响，我们已将其转化为人类后大脑 PD患者的组织。我们确定了哺乳动物及其的囊泡谷氨酸转运蛋白vglut2 果蝇直系同源物作为DA神经元弹性中性别差异的调节剂。我们发现：1） dvglut/vglut2+ da神经元比不表达的DA神经元更有可能生存 转运蛋白； 2）DA神经元中有条件的DVGLUT/VGLUT2基因敲除增加了侮辱的脆弱性； 3） dvglut/vglut2表达在幸存的DA神经元中被更新，以应对PD连接事件（包括） 衰老，错误折叠的A-核蛋白和神经毒素。此外，我们发现女性表达了更多 与雄性相比，DA神经元中的DVGLUT/VGLUT2 - 这一发现构成了苍蝇，啮齿动物和人类 这可以解释PD的性别差异。但是，是否在da Neuron vglut2表达中的性别差异是否存在 有助于对环境有毒物质等环境有毒物质和帕拉酸盐等环境有毒物质的韧性仍然未知。那，我们 假设DA Neuron DVGLUT/VGLUT2表达是保守的性二态神经保护的一部分 PD中环境有毒物质对DA神经元损伤的反应。为了检验我们的假设，我们发展了 跨苍蝇，啮齿动物和尸体后人脑的比较方法，以及新的遗传和成像 工具，确定VGLUT2是否调节DA神经元中的性别差异对农药rotorone （目标1）。我们还将确定DVGLUT-和VGLUT2介导的对农药的弹性的机制 男性和女性（目标2）。最后，我们将确定男性大脑中的DA Neuron vglut2表达 女性PD患者，包括已知暴露于农药七氯的受试者的大脑（AIM 3）。 由于环境有毒物质，确定VGLUT2在DA神经元弹性中的性别差异中的作用 暴露可能会为PD提供新的见解。此外，确定增加DA神经元的机制 女性的韧性可以转移到雄性中，以提高PD的DA神经元存活。这可能最终导致 在男性和女性中，新的有效治疗方法可以缓慢或停止PD神经退行性。