Dexamethasone Modulates Primed Neutrophil Function and Activation
MAKARI A. 1, BAUERDICK A. 1, KAHLICH F. 1, HABICHT J. 1, EXNER T. 1, GRIESHABER-BOUYER R. 1, WABNITZ G. 1
1 Institute of Immunology, Heidelberg University, Heidelberg, Germany
Inflammatory diseases often involve the activation of innate immune cells, specifically neutrophils, which undergo priming and functional changes within inflamed tissues. Glucocorticoids, renowned for their anti-inflammatory and immunosuppressive properties, include dexamethasone, an effective immunosuppressant targeting acute and chronic inflammatory responses. Previous research primarily focused on the effects of glucocorticoids on resting neutrophils, neglecting their primed state. To address this gap, our study employed flow cytometry and imaging flow cytometry techniques to explore how dexamethasone impacts primed neutrophils. Our results indicate that dexamethasone exerts regulatory effects on neutrophil activation by modifying the expression of various surface receptors and adhesion molecules, thereby influencing neutrophil function. Specifically, we observed a downregulation of CD11b, CD54, and PD-L1, alongside an upregulation of CD62L expression following dexamethasone treatment. Additionally, through transwell migration assays, we observed that dexamethasone enhances neutrophil migration in response to SDF-1 while selectively reducing other neutrophil functions such as phagocytosis and NETosis. The latter can have the potential to destroy tissues. It is noteworthy that dexamethasone does not completely inhibit all antibacterial effects of neutrophils, as it leaves the production of reactive oxygen species (ROS) and exocytosis unaffected. This observation underscores the selective impact of dexamethasone in preserving neutrophil-mediated antibacterial responses while minimizing potential tissue destruction.