The Gut-larynx Axis and its Contribution to Laryngeal Immunity

The larynx is essential for swallowing, breathing, coughing, and voice production, supported by its unique microbial and immunological environment. Our previous research highlighted the role of resident laryngeal microbiota in shaping local immune responses. With growing interest in the gut-lung axis—the bidirectional communication between gut and respiratory immunity—the potential influence of gut microbiota on laryngeal immunity warrants exploration. We hypothesized that a gut-larynx axis may exist, where both resident laryngeal and gut microbiota contribute to immune modulation in the larynx. To investigate this, we treated conventionally raised, wild-type C57BL/6J mice with an oral antibiotic regimen known to disrupt gut microbiota, comparing them to untreated controls. Following treatment, the gut microbiota was significantly disrupted, while the laryngeal microbiota remained largely unchanged. However, antibiotic-treated mice exhibited marked changes in epithelial and immune cell proportions, as well as fibroblasts. Differential gene expression across cell types highlighted pathways related to epithelial barrier integrity, immune signaling, and bacterial response. Additionally, gut dysbiosis affected gene regulatory networks, with the activity of regulons Etv4(+), Irf3(+), Hltf(+), Mga(+), and Nfil3(+) showing significant changes. Notably, cell-cell communication was also altered, especially in immune-epithelial interactions, with integrin-mediated signaling emerging as a key ligand-receptor pathway in these intercellular communications. These findings suggest that gut and laryngeal microbiota may work synergistically to modulate immune responses in the larynx, underscoring the importance of considering gut-larynx interactions in studies of respiratory immunity.