Getting Your Neutrophil: Neutrophil Transepithelial Migration in the Lung

ABSTRACT

Neutrophil transepithelial migration is a fundamental process that facilitates the rapid trafficking of neutrophils to inflammatory foci and occurs across a diverse range of tissues. For decades, there has been widespread interest in understanding the mechanisms that drive this migratory process in response to different pathogens and organ systems. This has led to the successful integration of key findings on neutrophil transepithelial migration from the intestines, lungs, liver, genitourinary tract, and other tissues into a single, cohesive model. However, recent studies have identified organ-specific differences in neutrophil transepithelial migration. These findings support a model where the tissue in concert with the proinflammatory stimuli dictates a unique collection of signals that drive neutrophil trafficking. This review focuses on the mechanisms that drive neutrophil transepithelial migration in response to microbial infection of a single organ, the lung. Herein, we provide a detailed analysis of the adhesion molecules and chemoattractants that contribute to the recruitment of neutrophils into the airways. We also highlight important advances in experimental models for studying neutrophil transepithelial migration in the lung over the last decade.