MicroRNAs (miRNAs) are key regulators of host–microbiome interactions. They influence diverse physiological processes through post-transcriptional gene regulation. Growing evidence indicates that host-derived miRNAs and microbially encoded miRNA-like molecules contribute to bidirectional signaling between the gut microbiota and the central nervous system. These interactions play a role in gut–brain axis communication. This review summarizes current findings on how host miRNAs shape microbial composition and function. It also examines emerging evidence that microbial miRNA-like molecules can modulate host gene expression. Particular attention is given to pathways involved in metabolic regulation, immune signaling, and neuroinflammatory processes relevant to gut–brain communication. In addition, we discuss the role of extracellular vesicles in miRNA transport and signaling. We critically assess the translational potential of miRNA-based biomarkers and therapeutic strategies, highlighting both their promise and current limitations. Overall, this review provides an integrated overview of miRNA-mediated host–microbiome interactions within the gut–brain axis and outlines key conceptual and experimental challenges that remain unresolved.
Bednarska et al. (Wed,) studied this question.