Abstract：
Gut metaproteomics can provide direct evidence of microbial functions actively expressed in the colonic environments, contributing to clarify the role of the gut microbiota in human physiology. In this study, we re-analyzed 10 fecal metaproteomics datasets of healthy individuals from different continents and countries, with the aim of identifying stable and variable gut microbial functions and defining the contribution of specific bacterial taxa to the main metabolic pathways. The \"core\" metaproteome included 182 microbial functions and 83 pathways that were identified in all individuals analyzed. Several enzymes involved in glucose and pyruvate metabolism, along with glutamate dehydrogenase, acetate kinase, elongation factors G and Tu and DnaK, were the proteins with the lowest abundance variability in the cohorts under study. On the contrary, proteins involved in chemotaxis, response to stress and cell adhesion were among the most variable functions. Random-effect meta-analysis of correlation trends between taxa, functions and pathways revealed key ecological and molecular associations within the gut microbiota. The contribution of specific bacterial taxa to the main biological processes was also investigated, finding that Faecalibacterium is the most stable genus and the top contributor to anti-inflammatory butyrate production in the healthy gut microbiota. Active production of other mucosal immunomodulators facilitating host tolerance was observed, including Roseburia flagellin and lipopolysaccharide biosynthetic enzymes expressed by members of Bacteroidota. Our study provides a detailed picture of the healthy human gut microbiota, contributing to unveil its functional mechanisms and its relationship with nutrition, immunity, and environmental stressors.
摘要：
肠道元蛋白质组学可以提供在结肠环境中活跃表达的微生物功能的直接证据。有助于阐明肠道微生物群在人体生理中的作用。在这项研究中,我们重新分析了来自不同大陆和国家的健康个体的10个粪便元蛋白质组学数据集，目的是鉴定稳定和可变的肠道微生物功能，并确定特定细菌类群对主要代谢途径的贡献。“核心”元蛋白质组包括182种微生物功能和83种途径，这些途径在所有分析的个体中得到鉴定。参与葡萄糖和丙酮酸代谢的几种酶，还有谷氨酸脱氢酶,醋酸盐激酶,伸长因子G和Tu和DnaK，是所研究队列中丰度变异性最低的蛋白质。相反,参与趋化性的蛋白质，对压力的反应和细胞粘附是最可变的功能之一。分类群之间相关趋势的随机效应荟萃分析，功能和途径揭示了肠道微生物群内的关键生态和分子关联。还研究了特定细菌类群对主要生物过程的贡献，发现粪杆菌是最稳定的属，也是健康肠道微生物群中抗炎丁酸产生的最大贡献者。观察到促进宿主耐受的其他粘膜免疫调节剂的主动产生，包括Roseburia鞭毛蛋白和由拟杆菌成员表达的脂多糖生物合成酶。我们的研究提供了健康人类肠道微生物群的详细图片，有助于揭示其功能机制及其与营养的关系，豁免权,和环境压力。
