Arsenical production in germ free and humanized mice

 描述(申请人提供)：砷中毒，或砷中毒，是一种世界性的公共健康威胁，导致包括癌症在内的各种人类疾病。人类胃肠道(GIT)的微生物群落(微生物群)对宿主暴露于含砷化合物(砷化合物)等有毒外来物质具有重要影响，但宿主与微生物群在砷生物转化中的个体作用尚不清楚。我们在小鼠身上的初步数据强烈表明，微生物组降低了宿主中的砷毒性。这项研究的广泛和长期目标是更好地了解人类微生物群中影响砷转化的功能成分，这些功能成分随后可以作为预防和/或解毒剂用于治疗和预防人类砷中毒的新策略。这项研究涉及微生物组在人类暴露于环境毒素中的作用，因此具体涉及国家环境健康科学研究所(NIEHS)的一个战略主题(“暴露研究”)和一个具体的战略目标(目标4，b部分)。作为确定人类微生物群在砷中毒中作用的第一步，特定目标1将确定无菌小鼠和被人类微生物群定居的无菌小鼠(人源化小鼠)的砷化合物的基线产量。无菌小鼠是完全无菌的，因此这些暴露在砷中的动物体内砷的产生将仅归因于宿主的新陈代谢。相比之下，人源化小鼠的砷产量将反映宿主和微生物的净影响，从而可以比较它们各自的作用。作为确定人类微生物组在砷中毒中的作用的下一步，特殊目标2将直接量化 小鼠胃肠道中微生物产生的砷活性酶在砷的水平上。在该项目的这一部分，无菌小鼠将与先前已被证明以特定方式代谢砷的基因定义的大肠杆菌菌株单一相关。从临时收集的小鼠组织和排泄物中，砷的产量将通过使用高效液相色谱和电感耦合等离子体质谱(HPLC-ICPMS)的最先进方法进行量化，相应的临时微生物组动态将使用编码基因元基因组的16S rRNA进行跟踪。这些数据将被分析在一起，为人体GIT微生物群体内砷的转化提供统计支持和实验证据。

 DESCRIPTION (provided by applicant): Arsenic poisoning, or arsenicosis, is a worldwide threat to public health, leading to a variety of human diseases, including cancer. The microbial community (microbiome) of the human GI tract (GIT) has been implicated as a significant influence on host exposure to toxic xenobiotics, including arsenic-containing compounds (arsenicals), but the individual roles of host vs. microbiome in arsenic biotransformation have not been clearly defined. Our preliminary data in mice strongly suggest that the microbiome decreases arsenic toxicity in the host. The broad, long-term objective of this research is to bette understand the functional components of the human microbiome that impact As-transformations in the GIT that can then be manipulated as prophylactic and/or detoxifying agents for use as novel treatment and prevention strategies against human arsenicosis. This research addresses the microbiome's role in human exposure to an environmental toxin and so specifically addresses a strategic theme ("Exposure Research") and a specific strategic goal (Goal 4, part b) of the National Institute of Environmental Health Sciences (NIEHS). As an initial step toward defining the role of the human microbiome in arsenicosis, Specific Aim 1 will establish the baseline production of arsenicals in germ free mice and germ free mice colonized with a human microbiome (humanized mice). Germ free mice are completely sterile and so arsenical production in these arsenic-exposed animals will be due to host metabolism alone. In contrast, arsenical production in humanized mice will reflect the net influence of host and microbe, thereby allowing a comparison of their individual roles. As the next step forward in defining the role of the human microbiome in arsenicosis, Specific Aim 2 will directly quantify the influence of microbially- produced, arsenic-active enzymes in the gastrointestinal tract on arsenical levels in gnotobiotic mice. In this part of the project, germ free mice will be mono-associated with genetically defined strains of Escherichia coli that have been shown previously to metabolize arsenic in specific ways. Arsenical production will be quantified from temporally collected mouse tissues and excretia by state-of-the-art methodology using high-performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICPMS) and corresponding temporal microbiome dynamics will be tracked using 16S rRNA encoding gene metagenomic sequencing. These data will be analyzed together to provide statistical support to and experimental evidence for the in vivo transformation of arsenic by the human GIT microbiome.