Mounting evidence indicates that gut microbiota exerts a broad range of effects on host physiology and development beyond the gastrointestinal tract, including the modulation of brain development. However, the mechanisms mediating the interactions between the microbiota and the developing brain are still poorly understood. Pattern recognition receptors of the innate immune system that recognize microbial products, such as peptidoglycans have emerged as potential key regulators of gut microbiome-brain interactions. Peptidoglycan-sensing molecules are expressed in the placenta and brain during specific time windows of development. Moreover, peptidoglycans are ubiquitously present in circulation and can cross the blood brain barrier. This review brings together the current evidence supporting a broad function of peptidoglycans well beyond host's immunity, extending to neurodevelopment and behavior.

中文翻译：

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细菌肽聚糖是从微生物群到大脑的新型信号分子。

越来越多的证据表明，肠道菌群对胃肠道以外的宿主生理和发育具有广泛的影响，包括对大脑发育的调节。但是，调解微生物群和发展中的大脑之间的相互作用的机制仍然知之甚少。识别微生物产物（例如肽聚糖）的先天免疫系统的模式识别受体已成为肠道微生物组-脑相互作用的潜在关键调节因子。在发育的特定时间窗期间，肽聚糖传感分子在胎盘和大脑中表达。此外，肽聚糖普遍存在于循环中，并且可以穿越血脑屏障。这项审查汇集了目前的证据，支持肽聚糖的广泛功能远远超出宿主的范围。