Respiratory syncytial virus (RSV) selectively targets ciliated cells in human bronchial epithelium and can cause bronchiolitis and pneumonia, mostly in infants. To identify molecular targets of intervention during RSV infection in infants, we investigated how age regulates RSV interaction with the bronchial epithelium barrier. Employing precision-cut lung slices and air-liquid interface cultures generated from infant and adult human donors, we found robust RSV virus spread and extensive apoptotic cell death only in infant bronchial epithelium. In contrast, adult bronchial epithelium showed no barrier damage and limited RSV infection. Single nuclear RNA-Seq revealed age-related insufficiency of an antiapoptotic STAT3 activation response to RSV infection in infant ciliated cells, which was exploited to facilitate virus spread via the extruded apoptotic ciliated cells carrying RSV. Activation of STAT3 and blockade of apoptosis rendered protection against severe RSV infection in infant bronchial epithelium. Lastly, apoptotic inhibitor treatment of a neonatal mouse model of RSV infection mitigated infection and inflammation in the lung. Taken together, our findings identify a STAT3-mediated antiapoptosis pathway as a target to battle severe RSV disease in infants.

Influenza A virus (IAV) remains a major global health threat, and host-directed antivirals may help overcome rapid viral mutation and drug resistance. Here, we performed a genome-wide siRNA screen in A549 cells using cell viability as an integrated endpoint to identify host determinants of IAV (PR8/H1N1) infection. Using plate-normalized viability ratios, we identified 2134 genes with >40% viability change after infection (2048 UP and 86 DOWN; two-tailed t-test, n = 3; p < 0.05, FDR < 0.1). MetaCore pathway analysis showed enrichment of programs linked to host response and tissue injury control, including RAS-related signaling and multiple metabolic pathways such as estradiol, ubiquinone/mitochondrial redox, and benzo[a]pyrene/xenobiotic metabolism. DAVID Gene Ontology analysis further highlighted biological processes relevant to infection, including endocytosis, transcription, and translation, consistent with host pathways supporting viral replication. Benchmarking against meta-analyzed RNAi and CRISPR resources revealed that shared hits were enriched for translation, nucleocytoplasmic transport, and ER-Golgi trafficking, supporting external validity, whereas the large unique UP fraction was dominated by hormone metabolism, detoxification, and mitochondrial redox/CoQ pathways, consistent with viability-specific, tolerance-associated host response programs. Integrating the screen with DrugBank identified 174 druggable host genes corresponding to 345 candidate compounds. Together, these findings provide a systematic resource of host factors influencing H1N1 infection, improve understanding of influenza virus–host interactions, and offer a foundation for future development of host-directed antiviral strategies and drug repurposing efforts.

Background: Allergic asthma develops from allergen exposure in early childhood and progresses into adulthood. The central mediator of progressive allergic asthma is allergen-specific, T helper 2 (Th2) resident memory cells (TRMs). Although the crosstalk between nerves and immune cells plays an established role in acute allergic inflammation, whether nerves facilitate the establishment of Th2-TRMs in the immature lung following early life allergen exposure is unknown. Objective: Our aim was to identify nerve-derived signals that act in Th2 effector cells to regulate the tissue residency in the immature lung. Methods: Following neonatal allergen exposure, allergen-specific Th2-TRMs were tracked temporally and spatially in relationship to developing sympathetic nerves in the lung. Functional mediators of dopamine signaling in the establishment of Th2-TRMs were identified by in vitro bulk RNA-seq of dopamine-treated Th2 cells followed by in vivo assessment of candidate genes using adoptive transfer of Th2 cells with viral gene knockdown. Results: We find that sympathetic nerves produce dopamine and reside in proximity to Th2 effector cells during the contraction phase following neonatal allergen exposure. Dopamine signals via DRD4 receptor on Th2 cells to elevate IL2Ra and epigenetically facilitate type 2 cytokine expression. Blockade of dopamine-DRD4 signaling following neonatal allergen exposure impairs lung residence of Th2 cells and ameliorates anamnestic inflammation in adults.