Mechanism of Corynebacterium striatum-mediated inhibition of Staphylococcus aureus-induced epithelial barrier injury and inflammation activation in chronic rhinosinusitis [RNA-Seq]

Microbes are an important trigger of chronic rhinosinusitis (CRS). Staphylococcus aureus is a CRS-related pathogen that disrupts the epithelial barrier and activates mucosal inflammation. Given the ineffectiveness of antimicrobial therapy in CRS, we explored a potential treatment based on the interaction of bacteria within the dysbiotic microenvironment of the nasal mucosa. Microbiome analyses of clinical isolates from CRS patients and healthy controls were employed to identify Corynebacterium striatum as a potential inhibitor of pathogenic S. aureus. A co-infection culture model using human nasal epithelial cells (hNECs) was constructed to investigate the inhibition of S. aureus-induced disruption of the host epithelium by C. striatum. Further analysis of the inhibition of S. aureus by C. striatum was carried out using a bacteria co-culture model. Overall design: The bacterial cultures used for infection experiments were prepared when hNECs were differentiated and matured. Briefly, cryopreserved bacterial strains were recovered by streaking on LB agar plates. A single colony was then picked and inoculated into LB liquid medium for overnight shake cultivation (37?, 220 rpm). After centrifugation and two washes with sterile phosphate-buffered saline (PBS), the bacterial suspension was quantified to an OD600 of 0.4 and applied onto the hNECs at a volume of 10 µL per insert, which precisely covered the entire surface of the hNEC layer. Both bacterial strains were treated in the same manner. To simulate symbiosis in the human nasal cavity, C. striatum was pre-inoculated and allowed to colonize the hNECs for 48 hours before infection with S. aureus for another 12 hours. The cells and media were then collected for experimental analysis.