韩国首尔国立大学Won-Jae Lee和韩国科学技术研究院Greg S. B. Suh研究小组合作的研究发现了果蝇肠道微生物-大脑通路如何响应氨基酸缺乏。相关论文于2021年5月5日在线发表在《自然》杂志上。
研究人员在果蝇中发现，肠道微生物组-脑通路可检测到必需氨基酸（EAAs）缺乏，并激活对EAA代偿性食欲。研究发现在蛋白质缺乏时，在前中肠的肠上皮细胞中神经肽CNMamide（CNMa）会被高度诱导表达。沉默CNMa–CNMa受体通路阻止了缺乏EAA果蝇的特异性饥饿驱动反应。
此外，带有产生EAA共生微生物组的既定微生物果蝇对EAA的食欲降低。相比之下，具有不产生亮氨酸或其他EAA突变微生物组的致癌果蝇表达较高CNMa和具有对EAA更大的补偿性食欲。该研究表明肠道肠上皮细胞感觉饮食和微生物组来源的EAA水平，并通过CNMa将EAA缺乏的信号传达给大脑。
研究人员表示，均衡摄入蛋白质、碳水化合物和脂肪等常量营养元素对于生物体的健康至关重要。摄入足够的热量但蛋白质消耗不足可能会导致多种疾病，包括kwashiorkor。味觉受体（T1R1-T1R3）可以检测微环境中的氨基酸，而细胞传感器（Gcn2和Tor）则可以感知细胞中的氨基酸水平。当机体缺乏蛋白质时，动物会选择摄入所含蛋白质或必需氨基酸比例更高的食物。这表明，在特定EAA缺乏的条件下，个体会优先选择能实现特定常量营养素目标量的食物，然而人们对这种选择的机制知之甚少。
附：英文原文
Title: Response of the microbiome–gut–brain axis in Drosophila to amino acid deficit
Author: Boram Kim, Makoto I. Kanai, Yangkyun Oh, Minsoo Kyung, Eun-Kyoung Kim, In-Hwan Jang, Ji-Hoon Lee, Sang-Gyu Kim, Greg S. B. Suh, Won-Jae Lee
Issue&Volume: 2021-05-05
Abstract: A balanced intake of macronutrients—protein, carbohydrate and fat—is essential for the well-being of organisms. An adequate calorific intake but with insufficient protein consumption can lead to several ailments, including kwashiorkor1. Taste receptors (T1R1–T1R3)2 can detect amino acids in the environment, and cellular sensors (Gcn2 and Tor)3 monitor the levels of amino acids in the cell. When deprived of dietary protein, animals select a food source that contains a greater proportion of protein or essential amino acids (EAAs)4. This suggests that food selection is geared towards achieving the target amount of a particular macronutrient with assistance of the EAA-specific hunger-driven response, which is poorly understood. Here we show in Drosophila that a microbiome–gut–brain axis detects a deficit of EAAs and stimulates a compensatory appetite for EAAs. We found that the neuropeptide CNMamide (CNMa)5 was highly induced in enterocytes of the anterior midgut during protein deprivation. Silencing of the CNMa–CNMa receptor axis blocked the EAA-specific hunger-driven response in deprived flies. Furthermore, gnotobiotic flies bearing an EAA-producing symbiotic microbiome exhibited a reduced appetite for EAAs. By contrast, gnotobiotic flies with a mutant microbiome that did not produce leucine or other EAAs showed higher expression of CNMa and a greater compensatory appetite for EAAs. We propose that gut enterocytes sense the levels of diet- and microbiome-derived EAAs and communicate the EAA-deprived condition to the brain through CNMa.
DOI: 10.1038/s41586-021-03522-2
Source: https://www.nature.com/articles/s41586-021-03522-2
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
