Short-chain fatty acids-producing probiotics: A novel source of psychobiotics

Psychobiotics—live microorganisms with potential mental health benefits, which can modulate the microbiota-gut-brain-axis via immune, humoral, neural, and metabolic pathways—are emerging as novel therapeutic options for the effective treatment of psychiatric disorders Recently, microbiome studies have identified numerous putative psychobiotic strains, of which short-chain fatty acids (SCFAs) producing bacteria have attracted special attention from neurobiologists. Recent studies have highlighted that SCFAs-producing bacteria such as Lactobacillus, Bifidobacterium and Clostridium have a very specific function in various psychiatric disorders, suggesting that these bacteria can be potential novel psychobiotics. SCFAs, potential mediators of microbiota-gut-brain axis, might modulate function of neurological processes. While the specific roles and mechanisms of SCFAs-producing bacteria of microbiota-targeted interventions on neuropsychiatric disease are largely unknown. This Review summarizes existing knowledge on the neuroprotective effects of the SCFAs-producing bacteria in neurological disorders via modulating microbiota-gut-brain axis and illustrate their possible mechanisms by which SCFAs-producing bacteria may act on these disorders, which will shed light on the SCFAs-producing bacteria as a promising novel source of psychobiotics.