Isotopic and genetic methods reveal the role of the gut microbiome in mammalian host essential amino acid metabolism
Isotopic and genetic methods reveal the role of the gut microbiome in mammalian host essential amino acid metabolism
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DOI：
10.1098/rspb.2019.2995
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发表时间：
2020-03-11
影响因子：
4.7
通讯作者：
Fogel, Marilyn L.
中科院分区：
文献类型：
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作者：
Newsome, Seth D.;Feeser, Kelli L.;Fogel, Marilyn L.
肠道微生物群为其宿主发挥许多功能，但其中最重要的是它们在新陈代谢中的作用，特别是将宿主无法消化的顽固生物质转化为生物可利用的化合物。大多数研究都集中在肠道微生物群在碳水化合物代谢中提供的帮助，然而，它们在宿主氨基酸代谢中的作用却知之甚少。我们对小家鼠进行了一项实验，利用 16S rRNA 基因测序和必需氨基酸 (AA(ESS)) 的碳同位素分析来量化肠道微生物群的群落组成，以及肠道微生物群使用碳水化合物碳合成 AA(ESS) 的贡献，AA(ESS) 被小鼠同化以构建骨骼肌组织。厚壁菌门和拟杆菌门的相对丰度与饮食大分子含量的函数成反比变化，当小鼠喂食含有最高比例的简单碳水化合物（蔗糖）的低蛋白饮食时，厚壁菌门占主导地位。混合模型估计，在饮食治疗中，AA(ESS) 对小鼠肌肉的微生物贡献从不到 5%（苏氨酸、赖氨酸和苯丙氨酸）到大约 60%（缬氨酸）不等，其中以厚壁菌门为主的微生物组贡献最大。我们的结果表明，肠道微生物可以提供宿主用来合成结构组织的 AA(ESS) 的重要来源。肠道微生物群在食用缺乏蛋白质饮食的动物的氨基酸代谢中所发挥的作用可能是觅食生态学和生理学的一个重要但未被充分认识的方面。
Intestinal microbiota perform many functions for their host, but among the most important is their role in metabolism, especially the conversion of recalcitrant biomass that the host is unable to digest into bioavailable compounds. Most studies have focused on the assistance gut microbiota provide in the metabolism of carbohydrates, however, their role in host amino acid metabolism is poorly understood. We conducted an experiment on Mus musculus using 16S rRNA gene sequencing and carbon isotope analysis of essential amino acids (AA(ESS)) to quantify the community composition of gut microbiota and the contribution of carbohydrate carbon used by the gut microbiome to synthesize AA(ESS) that are assimilated by mice to build skeletal muscle tissue. The relative abundances of Firmicutes and Bacteroidetes inversely varied as a function of dietary macromolecular content, with Firmicutes dominating when mice were fed low-protein diets that contained the highest proportions of simple carbohydrates (sucrose). Mixing models estimated that the microbial contribution of AA(ESS) to mouse muscle varied from less than 5% (threonine, lysine, and phenylalanine) to approximately 60% (valine) across diet treatments, with the Firmicute-dominated microbiome associated with the greatest contribution. Our results show that intestinal microbes can provide a significant source of the AA(ESS) their host uses to synthesize structural tissues. The role that gut microbiota play in the amino acid metabolism of animals that consume protein-deficient diets is likely a significant but under-recognized aspect of foraging ecology and physiology.