NIH Plunk The Effects of Gestational and Lactational Exposure to Perfluorohexanoic Acid on Cerebellum Development in the Mouse

项目摘要 全氟己酸（PFHxA）是一种短链全氟和多氟烷基物质（PFAS），用于工业生产。 和消费品，例如水性成膜泡沫（AFFF）、食品包装纸、家具上的防污剂， 还有化妆品PFHxA的使用在美国不受监管。PFHxA在环境中普遍存在 严重污染土壤和水，导致人类通过摄入接触。流行病学 文献已经报道了PFHxA在母体血清和母乳中，并且PFHxA穿过胎盘。我们一起努力， 这些数据表明，胎儿通过胎盘接触，婴儿通过母乳喂养接触。在 在人类中，PFHxA在小脑中的积累高于大多数其他大脑区域。小脑很关键 运动和认知功能，是50%的神经元的家园，具有独特的细胞结构， 发育晚于其他区域，使其成为发育毒物研究的重要区域 暴露。虽然PFHxA对健康的影响在很大程度上尚未研究，但已经确定传统PFAS 改变免疫功能，包括抑制外周免疫反应。然而，PFHxA对 大脑的免疫细胞小胶质细胞尚未得到研究。小神经胶质细胞有着相同的 起源于外周免疫细胞，表明发育暴露可能针对小胶质细胞功能。 有趣的是，小脑中的小胶质细胞可能比小胶质细胞对神经毒物特别敏感 因为它们有独特的转录组学特征。除了免疫功能，小胶质细胞还发挥着 通过帮助血管生成，提供髓鞘发育的因子，在脑发育中起关键作用， 修剪突触从而重塑神经回路因此，发育PFHxA暴露可能会影响他们的 免疫和神经解剖学功能。尽管小胶质细胞在大脑发育和证据中的重要性 PFHxA进入大脑，PFHxA尚未在哺乳动物神经系统中进行研究。基于 根据PFHxA和长链PFAS流行病学研究的证据，我假设妊娠期和 哺乳期暴露于PFHxA的小鼠模型破坏小脑发育，影响神经元和神经胶质细胞 表型以及运动活动。小胶质细胞可能受到这种暴露的独特影响， 免疫抑制为了验证这一假设，我将使用代表人类的小鼠模型来追求两个目标。 在妊娠期和哺乳期暴露于PFHxA。第一个目标是研究妊娠期和哺乳期 使用RNA测序和免疫组织化学研究暴露于PFHxA影响神经元和神经胶质细胞表型 （IHC）。这一目标还将调查这种暴露如何影响动物的行为，特别是那些与环境有关的行为。 小脑第二个将确定小胶质细胞是否在遗传，蛋白质和动态水平上改变， RNA测序，免疫组化，和双光子显微镜。这些实验将首次表明， 大脑发育期间的PFHxA暴露具有神经毒性，也将指导多个机构的监管机构 当考虑PFHxA暴露于人类时。

Project Summary Perfluorohexanoic acid (PFHxA) is a short-chain per- and polyfluoroalkyl substance (PFAS) used in industrial and consumer products, such as aqueous film forming foam (AFFF), food wrappers, stain repellants on furniture, and makeup. PFHxA use is not regulated in the United States. PFHxA is found ubiquitously in the environment significantly contaminating soil and water resulting in humans being exposed through ingestion. Epidemiology literature has reported PFHxA in maternal serum and breastmilk, and PFHxA crosses the placenta. Together, these data demonstrate that fetuses are exposed through the placenta and infants through breast feeding. In humans, PFHxA accumulates higher in the cerebellum than in most other brain regions. The cerebellum is critical to both motor and cognitive functions, is the home of 50% of the neurons, has a unique cytoarchitecture, and develops later than other regions making it an important region to study in the context of developmental toxicant exposures. While the health effects of PFHxA are still largely unstudied, it is well established that legacy PFAS alter immune function, including suppressing peripheral immune responses. However, the effects of PFHxA on the immune cells of the brain, microglia, have not been investigated. Microglia have the same mesodermal origins as peripheral immune cells, suggesting that developmental exposures may target microglial function. Interestingly, microglia in the cerebellum may be particularly sensitive to neurotoxicants compared to microglia in other brain regions as they have a unique transcriptomic profile. In addition to immune function, microglia play a critical role in brain development by aiding in angiogenesis, providing factors for myelin development, and pruning synapses thereby remodeling neural circuits. Thus developmental PFHxA exposure could affect their immune and neuroanatomical functions. Despite the importance of microglia in brain development and evidence that PFHxA enters the brain, PFHxA has not been investigated in the mammalian nervous system. Based on evidence from epidemiology studies on PFHxA as well as long-chain PFAS, I hypothesize that gestational and lactational exposure to PFHxA in a mouse model disrupts cerebellar development, affecting neuronal and glial phenotypes, as well as motor activity. Microglia may be uniquely affected by this exposure, becoming immunosuppressed. To test this hypothesis, I will pursue two aims using a mouse model representing human exposure to PFHxA during gestation and lactation. The first aim will investigate how gestational and lactational exposure to PFHxA affects neuron and glia phenotypes using RNA sequencing and immunohistochemistry (IHC). This aim will also investigate how this exposure affects animal behaviors, especially those related to the cerebellum. The second will determine if microglia are altered at the genetic, protein, and dynamic level by using RNA sequencing, IHC, and two-photon microscopy. These experiments will show, for the first time, whether PFHxA exposure during brain development is neurotoxic and will also guide regulators from multiple agencies when considering PFHxA exposure to humans.