美国德克萨斯大学西南医学中心Lora V. Hooper小组发现，微生物群与昼夜时钟协调先天免疫的昼夜节律。相关论文于2021年7月28日在线发表在《细胞》杂志上。

研究人员表明，肠道微生物群在先天免疫中产生昼夜节律，与摄食节律同步，从而预测微生物暴露。抗菌蛋白的节律性表达是由节段性丝状细菌（SFB）上皮附着的每日节律所驱动的。节律性的SFB附着是由昼夜钟通过控制进食节律驱动的。

从机制上讲，节律性的SFB附着激活了第3组先天淋巴细胞的免疫回路。这个回路触发了上皮细胞STAT3表达和激活的振荡，产生了有节奏的抗菌蛋白表达，最终导致对伤寒沙门氏菌感染的抵抗力在昼夜周期中变化。因此，宿主的进食节律与微生物群同步，从而促进肠道先天免疫的节律，并预料外源性微生物的暴露。

据悉，环境中的光周期会诱导动物的昼夜进食行为，从而在接触食源性细菌的过程中产生节律。

附：英文原文

Title: The microbiota coordinates diurnal rhythms in innate immunity with the circadian clock

Author: John F. Brooks, Cassie L. Behrendt, Kelly A. Ruhn, Syann Lee, Prithvi Raj, Joseph S. Takahashi, Lora V. Hooper

Issue&Volume: 2021-07-28

Abstract: Environmental light cycles entrain circadian feeding behaviors in animals that producerhythms in exposure to foodborne bacteria. Here, we show that the intestinal microbiotagenerates diurnal rhythms in innate immunity that synchronize with feeding rhythmsto anticipate microbial exposure. Rhythmic expression of antimicrobial proteins wasdriven by daily rhythms in epithelial attachment by segmented filamentous bacteria(SFB), members of the mouse intestinal microbiota. Rhythmic SFB attachment was drivenby the circadian clock through control of feeding rhythms. Mechanistically, rhythmicSFB attachment activated an immunological circuit involving group 3 innate lymphoidcells. This circuit triggered oscillations in epithelial STAT3 expression and activationthat produced rhythmic antimicrobial protein expression and caused resistance to Salmonella Typhimurium infection to vary across the day-night cycle. Thus, host feeding rhythmssynchronize with the microbiota to promote rhythms in intestinal innate immunity thatanticipate exogenous microbial exposure.

DOI: 10.1016/j.cell.2021.07.001

Source: https://www.cell.com/cell/fulltext/S0092-8674(21)00827-8