RNA sequencing of nasal lavage samples from mock- and Streptococcus pneumoniae-infected infant and adult mice

Acute respiratory infections (ARI), which generally begin with colonization of the mucosal surfaces of the upper respiratory tract (URT), are a leading cause of morbidity and mortality with the highest rate in infants. As a common colonizer of the URT, and one of the most prevalent causes of life-threatening infections in the pediatric population, Streptococcus pneumoniae (Spn) was used as a model pathogen to investigate the effect of age during URT infection. We used RNA-sequencing to transcriptionally profile and compare the mucosal epithelia of infant and adult mice at baseline (mock-infected) and during Spn infection. Analysis of the screen revealed an age-dependent alteration of genes involved in mucosal defense mechanisms that included dampened expression of ubiquitous antimicrobial molecules and tight junction proteins in infant mice compared to adults. These results demonstrate a window of vulnerability during postnatal development when altered mucosal barrier function may facilitate bacterial colonization and invasion. We performed gene expression profiling of the nasal epithelium and associated tissue from mock- and Streptococcus pneumoniae-infected infant and adult mice, with a n=5 per group.