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Oxygen-dependent changes in lung development do not affect epithelial infection with influenza A virus

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AJP Lung Cellular and Molecular Physiology

Published online on

Abstract

Infants born prematurely often require supplemental oxygen that contributes to aberrant lung development and increased pulmonary morbidity following a respiratory viral infection. We have been using a mouse model to understand how early-life hyperoxia affects the adult lung response to influenza A virus (IAV) infection. Prior studies showed how neonatal hyperoxia (100% oxygen) increased sensitivity of adult mice to infection with influenza A virus (IAV (A/Hong Kong/X31) H3N2) as defined by persistent inflammation, pulmonary fibrosis, and mortality. Since neonatal hyperoxia alters lung structure, we used a novel fluorescently expressing reporter strain of H1N1 IAV (A/Puerto Rico/8/34 mCherry, PR8 mCherry) to evaluate whether it also altered early infection of the respiratory epithelium. Like HKx31, neonatal hyperoxia increased morbidity and mortality of adult mice infected with PR8-mCherry. Whole lung imaging and histology suggested a modest increase in mCherry expression in adult mice exposed to neonatal hyperoxia when compared to room air exposed animals. However, this did not reflect an increase in airway or alveolar epithelial infection when mCherry + cells were identified and quantified by flow cytometry. Instead, a modest increase in the number of CD45+ macrophages expressing mCherry was detected. While neonatal hyperoxia does not alter early epithelial infection to IAV, it may increase the activity of macrophages towards infected cells thereby enhancing early epithelial injury.