Sinonasal Epithelial Cell Response toStaphylococcus aureusBurden in Chronic Rhinosinusitis

Abstract

Importance Chronic rhinosinusitis (CRS) is an inflammatory disorder of the nose and paranasal sinuses. Staphylococcus aureus is increasingly linked with CRS exacerbations. Little is known about how bacteria activate inflammatory pathways that contribute to CRS. Objective Here, we developed an in-vitro co-culture system to explore how infection with Staphylococcus aureus stimulates innate immune responses of sinonasal epithelial cells (SNEC). Design, Setting, and Subjects SNEC were collected from 13 patients during endoscopic sinus surgery and grown in culture at the air-liquid interface. Interventions Differentiated SNEC from control, CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP) patients were infected with Staphylococcus aureus at three different concentrations for 24-hours. Main Outcomes and Measures Growth of S. aureus and viability of SNEC were measured. Expression of inflammatory markers and innate immune genes were measured by RT-PCR. Basal secretion of IL-8 was determined by ELISA. Results Cultured SNEC from CRSsNP patients demonstrated a significant increase in expression of IL-8, and TNFα at all the tested concentrations of Staphylococcus aureus. Control or CRSwNP SNEC demonstrated a significant increase in expression only at the higher inoculum of Staphylococcus aureus. Basal secretion of inflammatory markers correlated with expression changes. No significant changes in expression were observed for the Th2 inflammatory mediators tested. Conclusions and Relevance In this study, we have developed a model to study early innate-immune mediated changes in sinonasal epithelial cells co-cultured at an air-liquid interface with bacteria. We also demonstrate that bacterial burden can be detected by SNEC in the absence of adaptive immune-mediated responses. CRSsNP SNECs are more sensitive to S. aureus burden than control or CRSwNP SNEC. Future studies will further develop this infection model and explore the SNEC innate immune response to bacteria.

Bactericidal antibiotics promote reactive oxygen species formation and inflammation in human sinonasal epithelial cells

“…Previous work demonstrated an increase in expression of these mediators as a result of infection of cultured SNECs with S. aureus 25 . To explore if antibiotic-mediated ROS formation promotes a pro-inflammatory state, we looked at the expression of TNF -α and IL-8 in SNECs following 24-hours of treatment with no antibiotics, clarithromycin, levofloxacin or amoxicillin (Figure 3A).…”

Influence of Ag content on the antibacterial properties of SiC doped hydroxyapatite coatings

“…), urinary infections [54,55], and respiratory infections (e.g. rhinosinusitis [56,57], and food poisoning [58][59][60]. It may be also involved in systemic infections [61,62].…”

Reduced Innate Immune Response to a Staphylococcus aureus Small Colony Variant Compared to Its Wild-Type Parent Strain

“…This mucosal surface is part of the first line innate defense as this is the site where pathogens interface with hosts. Previous in vitro studies have shown that epithelial cells infected with wild type S. aureus had increased expression of cytokines/chemokines including interleukin (IL)6 (Damm et al, 2006; Sachse et al, 2010), CXCL8 (Damm et al, 2006; Kohanski and Lane, 2015) and tumor necrosis factor (TNF) (Li et al, 2009; Kohanski and Lane, 2015) and tissue remodeling factors such as matrix metalloproteinases (MMPs) (Homma et al, 2015). An in vitro study by Tuchscherr et al showed increased expression of C-C motif chemokine ligand (CCL) 5, C-X-C motif ligand (CXCL) 10 and 11, and intracellular adhesion molecule (ICAM)1 when endothelial cells were infected with wild type S. aureus but not S. aureus SCVs (Tuchscherr et al, 2010).…”