Title : Neurobiology of the gut brain axis: Translating microbiome science into mental health care
Abstract:
The gut brain axis represents a complex, bidirectional communication network integrating the enteric nervous system and the central nervous system through neural, endocrine, immune, and metabolic pathways. Beyond its anatomical connections, this dynamic system operates via the autonomic nervous system, the hypothalamic–pituitary–adrenal (HPA) axis, neuroimmune signaling, microbial metabolites, and circulating humoral factors. Within this framework, the gut microbiota functions as a critical regulatory interface. Through modulation of vagal nerve signaling, neurotransmitter production (including serotonin, dopamine, and gamma-aminobutyric acid), short-chain fatty acid synthesis, immune activation, and inflammatory cytokine release, intestinal microbes actively influence brain function. Simultaneously, central stress responses mediated by the HPA axis alter gut permeability, motility, microbial composition, and mucosal immunity. This reciprocal interaction has significant implications for mood regulation, cognitive processes, stress responsiveness, and the pathophysiology of psychiatric and neurodevelopmental disorders. Emerging evidence suggests that microbial dysbiosis may contribute to conditions such as depression, anxiety, and stress-related disorders through mechanisms involving neuroinflammation, altered neurotransmission, and impaired barrier integrity. Understanding the gut–brain axis thus represents a paradigm shift in mental health research, offering new opportunities for preventive strategies, nutritional interventions, and microbiota-targeted therapeutics. Continued interdisciplinary and international collaboration will be essential to translate microbiome science into equitable, evidence-based mental health care worldwide.
