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