EV miRs in cognitive function decline associated with early life metal exposure

项目摘要/摘要 早年接触超级基金金属毒物，如铅(铅)、砷(As)、镉(Cd)和 在衰老过程中，锰与认知功能下降有关，并被怀疑是 导致神经退行性疾病的发展，如阿尔茨海默病。然而， 这些联系背后的生物学机制仍然知之甚少。哺乳动物细胞，包括 神经元和神经干细胞，分泌到细胞外环境中的各种微囊膜 水泡。这些胞外小泡(EV)含有功能性信号分子，可被 受体细胞来调节细胞间的通讯。其中一组信号分子是 MicroRNAs，通过降解目标mRNA和/或发挥基因表达的主调谐器的作用 禁止消息的翻译。由于EVS被脂质双层膜包裹，分子 例如包裹在囊泡中的microRNA受到保护，不受核酸酶介导的降解，因此 因此非常稳定。因此，可以很容易地在生物液中检测和定量EV microRNAs 例如血浆/血清，并已被用作各种人类疾病的新生物标记物。虽然 一些有限的研究探索了肠道病毒microRNAs在神经细胞中的作用，还没有研究检验 EV microRNAs在金属等环境暴露中对认知功能的作用 毒药。我们假设，在生命早期接触金属会改变大脑中的EV microRNA，这些 EV microRNAs的变化影响神经元和神经干细胞加速认知的功能 衰老。我们提出了三个相互关联的具体目标来检验这一假设。目标1将决定 暴露于单个金属暴露(铅、砷、锰和镉)以及“真实世界”金属的影响 混合物(在圣路易斯谷超级基金现场收集的修复前和修复后的水样) 发育中的人胎脑器官。目标2将确定早期接触个体的影响 金属(铅和砷)以及现实世界中的金属混合物对电动汽车MIR和认知功能的影响 老鼠在生命的后期。目标3将确定选定的EV microRNAs在调节功能中的功能作用 小鼠的大脑器官和认知功能的关系。我们整合鼠标的高度多学科研究 模型、人类流行病学和功能细胞研究试图建立EV microRNAs不仅是 金属暴露相关认知功能的新生物标志物，也是金属- 诱发的神经毒性和认知功能障碍。该项目通过以下方式与MEMCARE-SRC相联系 补充项目1中的人体研究，并寻求确定生物机制对健康的影响 超级基金站点的水污染。

PROJECT SUMMARY/ ABSTRACT Early-life exposure to Superfund metal toxicants such as lead (Pb), arsenic (As), cadmium (Cd) and Manganese (Mn) has been associated with worse cognitive function during aging and is suspected of contributing to the development of neurodegenerative diseases, such as Alzheimer’s disease. However, the biological mechanisms underlying the associations remain poorly understood. Mammalian cells, including neurons and neural stem cells, secrete into the extracellular milieu a variety of tiny membrane-encapsulated vesicles. These extracellular vesicles (EVs) contain functional signaling molecules that can be taken up by recipient cells to mediate intercellular communication. One such group of signaling molecules is microRNAs, which function as master tuners of gene expression by degrading target mRNA and/or inhibiting translation of the message. Since EVs are encapsulated by a lipid bilayer membrane, molecules such as microRNAs enclosed in the vesicles are protected from nuclease-mediated degradation and thus are thus very stable. As a result, EV microRNAs can be easily detected and quantitated in biological fluids such as plasma/serum and have been used as novel biomarkers for a variety of human diseases. Although some limited studies have explored the role of EV microRNAs in neural cells, no studies have examined the role of EV microRNAs on cognitive function in the context of environmental exposures such as metal toxicants. We hypothesize that metal exposures in early life alter EV microRNAs in the brain and that these changes in EV microRNAs affect the function of neurons and neural stem cells to accelerate cognitive aging. We propose three interconnected Specific Aims to test this hypothesis. Aim 1 will determine the effects of exposures to individual metal exposures (Pb, As, Mn, and Cd) as well as “real-world” metal mixtures (pre- and post-remediation water samples collected at the San Luis Valley Superfund site) on developing human fetal brain organoids. Aim 2 will determine the effects of early-life exposure to individual metals (Pb and As) as well as to the real-world metal mixtures on EV miRs and the cognitive function of mice later in life. Aim 3 will determine the functional role of selected EV microRNAs in modulating functions of brain organoids and cognitive function in mice. Our highly multidisciplinary study integrating mouse models, human epidemiology, and functional cellular studies seeks to establish EV microRNAs not only as novel biomarkers for metal exposure-related cognitive function, but also as a mechanistic basis for metal- induced neurotoxicity and cognitive impairment. This project links with the MEMCARE-SRC by complementing human studies in Project 1 and seeking to identify biologic mechanisms for health effects of water contamination at Superfund sites.