Does microbiome composition moderate GI and CNS function in a VPA-induced mouse model of autism?

项目摘要 30%-80%的自闭症患者会出现胃肠道问题，并可能导致严重的疼痛和痛苦。因此，有 迫切需要了解ASD中为什么会出现胃肠道症状，并开发更有效的干预措施。 最近的研究表明，肠道微生物群可能与ASD的胃肠道问题有关。自闭症患者不同于 他们携带的微生物的控制，可能与自闭症相关的饮食偏好和 ASD相关基因和ASD相关环境暴露对肠道发育和功能的不利影响。 此外，ASD患者的微生物转移在无菌小鼠中诱导了类似ASD的行为，提示 这些差异，无论其原因如何，都会导致行为问题。此外，最近的开放标签试验 粪便移植和一种在肠道中结合和隔离芳香代谢物的药物的研究表明 在自闭症患者中取得了有希望的结果。虽然这些发现令人振奋，但在以下方面仍有许多工作要做 ASD患者肠道微生物区系与GI和CNS功能之间的生物学机制。主要的目标是- 本研究的目的是评价人源化肠道微生物对丙戊酸血症患者胃肠道和中枢神经系统功能的影响。 酸(VPA)诱导的ASD小鼠模型。我们将通过两个目标实现这一目标。在目标1中，我们将确定 如果肠道微生物组组成缓解了产前VPA暴露对GI功能的影响，则会产生三种 具有不同微生物群的动物组：无特定病原体(SPF)的小鼠，具有人类肠道微生物群的小鼠 以双歧杆菌(BIF)为主的生物群和以类杆菌属为主的人肠道微生物群的小鼠 (BAC)。一半的动物将在怀孕第13天暴露于VPA(500毫克/公斤)，另一半将接受 假待遇。我们将评估活的成年后代的结肠运输和肠道通透性，辨别神经- 肠道组织采用免疫组织化学染色和RT-PCR，进行体外结肠动力测定，测定INTERS- 并用电生理学方法记录从肠神经和肌细胞分离出来的 肠道准备研究突触和环行肌的神经传递。在目标2中，我们将确定 肠道微生物组组成是否缓和了产前VPA暴露对中枢神经系统结构和功能的影响 功能。使用与目标1相同的组，我们将评估青少年和成年人的行为，使用公认的 与ASD直接相关的范例。为了研究潜在的机制，我们将评估神经炎症， 树突形态，以及海马体、杏仁核和前额叶皮质(PFC)的髓鞘形成。建议数 这项研究在将ASD-妊娠VPA暴露-与成熟的临床前模型相结合方面具有创新性 移植婴儿时期收集的人类微生物群落，这是ASD病因学的关键时期。这个 拟议的研究具有重要意义，因为它将加深我们对肠道微生物群在胃肠道和中枢神经系统中作用的理解 与ASD相关的功能。该项目将产生积极影响，因为它将提供信息和 新的建模方法，将促进与微生物组相关的新干预措施的开发。 穿着自闭症的核心症状和共病，包括智力残疾、焦虑和胃肠道问题。

Project Summary GI issues occur in 30-80% of autistic individuals and may result in significant pain and distress. Thus, there is an urgent need to understand why GI symptoms occur in ASD and to develop more effective interventions. Recent research suggests the gut microbiome may contribute to GI issues in ASD. Autistic people differ from controls in the microbes they carry, patterns that may be linked to autism-related dietary preferences and the adverse effects of ASD linked genes and ASD linked environmental exposures on gut development and function. In addition, transfer of microbes from people with ASD induces ASD-like behaviors in germ-free mice suggesting these differences, regardless of their causes, contribute to behavioral issues. Further, recent open label trials of fecal matter transplant and of a drug that binds and sequesters aromatic metabolites in the gut have shown promising results in autistic people. While these findings are exciting, there is still much to be done in terms of mapping the biological mechanisms connecting gut microbiota to GI and CNS function in ASD. The main objec- tive of this study is to evaluate the effect of humanized gut microbiomes on GI and CNS function in a valproic acid (VPA)-induced mouse model of ASD. We will achieve this objective via 2 aims. In Aim 1, we will determine if gut microbiome composition moderates the impact of prenatal VPA exposure on GI function by creating three groups of animals with differing microbiomes: specific pathogen-free (SPF) mice, mice with a human gut micro- biome dominated by Bifidobacterium (BIF), and mice with a human gut microbiome dominated by Bacteroides (BAC). Half of the animals will be exposed to VPA (500 mg/kg) on day 13 of gestation and half will receive a sham treatment. We will assess colonic transit and intestinal permeability in live adult offspring, discern neuro- enteric organization using immunostaining and RT-PCR, conduct ex vivo colonic motility assays, measure intes- tinal inflammation, and use electrophysiological methods to record from enteric nerve and muscle cells in isolated preparations of intestine to study synaptic and circular muscle neurotransmission. In Aim 2, we will determine whether gut microbiome composition moderates the impact of prenatal VPA exposure on CNS structure and function. Using the same groups as in Aim 1, we will evaluate juvenile and adult behavior using well established paradigms directly relevant to ASD. To investigate underlying mechanisms, we will assess neuroinflammation, dendritic morphology, and myelination in hippocampus, amygdala, and prefrontal cortex (PFC). The proposed study is innovative in combining a well-established preclinical model for ASD – gestational VPA exposure – with transplant of human microbial communities collected during infancy, a key period in the etiology of ASD. The proposed study is significant as it will enhance our understanding of the gut microbiome’s role in GI and CNS functions relevant to ASD. The project will have a positive impact because it will provide information and a novel modelling approach that will facilitate the development of novel microbiome-related interventions to ad- dress core ASD symptoms and comorbidities including intellectual disability, anxiety and GI issues.