View Abstract

A7721 - Differential Transcriptome Responses in Infant and Adult Airway Epithelium Following H1N1 Influenza Infection
Author Block: M. dela Pena-Ponce1, D. Dugger1, V. Kohli2, H. Ji3, C. Chaplin1, J. Ngo1, L. A. Miller4; 1California National Primate Research Center, University of California, Davis, Davis, CA, United States, 2Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, 3UC Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States, 4School of Veterinary Medicine, Anatomy, Physiology and Cell Biology, University of California, Davis, Davis, CA, United States.
Rationale: Immune function of postnatal lung epithelium is incompletely understood despite the known susceptibility of pediatric subjects to morbidity and mortality from respiratory viruses that directly target this cell population. Using the rhesus macaque monkey as a laboratory animal model of lung development, we have reported that pandemic influenza A/H1N1 virus infection of infant animals resulted in persistent distal airways inflammation and enhanced airway epithelial cell viral replication in vitro. Based upon our previous findings, we hypothesize that gene signatures associated with antiviral immunity in airway epithelium are dependent upon chronologic age.
Methods: To test our hypothesis within the context of respiratory virus infection, primary tracheobronchial epithelial cell cultures derived from either infant or adult rhesus monkeys were evaluated by RNA-seq at 24 hours following in vitro infection with A/California/04/2009 H1N1 or UV-inactivated H1N1 at MOI=1. Immunohistochemical staining of lung tissue and Luminex multiplex immunoassays of culture supernatants were used to correlate gene signatures with protein expression.
Results: From 21,807 genes detected in uninfected infant and adult cell cultures, we identified 552 differentially genes. The 353 genes that were down-regulated in infant cells were significantly enriched for gene ontology (GO) biological processes involved in immunity, including antiviral responses (OASL, IFITM1, IRF7), mucociliary components (MUC5B, RSPH1, FOXJ1, and DNAH11), antimicrobial molecules (LTF, LCN2, and DEFB4A), cytokine/chemokine pathways (IRAK3, CXCL10, and CXCL11) and immunoglobulin transport (PIGR). The 199 genes that were up-regulated were enriched for GO biological processes implicated in growth and development, including growth/signaling (GPC3, PDE6G), cell adhesion/mobility (PALLD, PTN, PCDH15), tissue remodeling (ADAMTS20, POSTN, EDIL3, MMP16), and embryonic development (DKK3, IRX1, WNT11, DACT1, CRISPLD2). H1N1 virus significantly altered the expression of 16 genes (ISG15, IFI6, IFI27, IFIT3, IFIT2, DDX58, IRF7, RSAD2, IFIH1, OAS3, PARP14, DHX58, HELZ2, STAT1, OAS1, SAMHD1) associated with immunity and antiviral defense in infant cells at 24 hours post-infection with minimal changes in the gene signature of growth and development within this age group. Protein expression correlated with transcript levels.
Conclusions: In our study, we identified significant differences in the airway epithelial cell transcriptome from two widely separated age groups using a nonhuman primate animal model to recapitulate the human lifespan. The transcriptome of infant airway epithelium is defined by a gene signature of cellular differentiation and host defense that is distinct from adult airway epithelium, suggesting that limited maturation of epithelial cells in the postnatal lung may contribute to enhanced pathology in pediatric respiratory virus infections.