Microbial regulation of serotonin and neuroimmune interactions

Bidirectional communication between the gut microbiota and neuroimmune system is essential during host-microbiome interactions. Recent research has begun to unravel microbiome-neuroimmune crosstalk and suggest classical neurochemicals as key molecular players. Serotonin, a tryptophan-derived neurochemical found across the kingdom of life, is increasingly recognized as an important effector molecule central to interkingdom communication. Here, we focus on serotonin as a key factor for microbiome-neuroimmune interaction. We briefly summarize the serotonergic system and the role of the gut microbiome in regulating serotonin bioavailability, which leads to downstream effects on neuroimmune responses and microbial fitness.