Gut microbes are known to impact host physiology in several ways. However, key molecular players in host-commensal interactions remain to be uncovered. In this issue of Cell, McCurry et al. reveal that gut bacteria perform 21-dehydroxylation to convert abundant biliary corticoids to neurosteroids using readily available H₂ in their environment.

中文翻译：

---

揭开信使的面纱：肠道微生物发出神经活性信号

众所周知，肠道微生物会通过多种方式影响宿主的生理机能。然而，宿主-共生相互作用中的关键分子参与者仍有待发现。在本期《细胞》杂志中，McCurry 等人。揭示肠道细菌利用环境中容易获得的 H ₂进行 21-脱羟基，将丰富的胆汁皮质激素转化为神经类固醇。