Proteomic analysis reveals down-regulation of surfactant protein B in murine type II pneumocytes infected with influenza A virus

Abstract

Infection of type II alveolar epithelial (ATII) cells by influenza A viruses (IAV) correlates with severe respiratory disease in humans and mice. To understand pathogenic mechanisms during IAV infection of ATII cells, murine ATII cells were cultured to maintain a differentiated phenotype, infected with IAV-PR8, which causes severe lung pathology in mice, and proteomics analyses were performed using liquid chromatography-mass spectrometry. PR8 infection increased levels of proteins involved in interferon signaling, antigen presentation, and cytoskeleton regulation. Proteins involved in mitochondrial membrane permeability, energy metabolism, and chromatin formation had reduced levels in PR8-infected cells. Phenotypic markers of ATII cells in vivo were identified, confirming the differentiation status of the cultures. Surfactant protein B had decreased levels in PR8-infected cells, which was confirmed by immunoblotting and immunofluorescence assays. Analysis of ATII cell protein profiles will elucidate cellular processes in IAV pathogenesis, which may provide insight into potential therapies to modulate disease severity.

Rhinovirus reduces the severity of subsequent respiratory viral infections by interferon-dependent and -independent mechanisms

“…We confirmed this by quantifying infectious RV in homogenized lung tissue and broncho-alveolar lavage fluid (BALF) 24 h and 48 h after RV inoculation, days -1 and 0, respectively. In agreement with published studies and our RNA-seq results, low levels of RV were detected on day -1, but not day 0 (S10 Fig which are known to be expressed at high levels during infection (40)(41)(42).…”

“…Our sequencing protocol only captured polyadenylated RNAs, thus these reads represent viral mRNAs and not complementary (cRNA) or genomic (vRNA) viral RNAs. Based on individual gene mapping, the PR8 reads predominantly mapped to the nucleoprotein (NP) and hemagglutinin (HA) mRNAs (S2 Fig), which are known to be expressed at high levels during infection (38)(39)(40). PVM gene expression was highest on day 4 and was robustly suppressed in RV-coinfected mice (Fig 4).…”

Lung epithelial cells have virus-specific and shared gene expression responses to infection by diverse respiratory viruses

“…Although susceptible mice mount a type I IFN response to PR8 infection, lethal infection is associated with spread of virus to the alveoli and an excessive inflammatory response [10][11][12][13]. PR8 replicates in bronchiolar and alveolar epithelial cells of the lower respiratory tract in vivo and in primary murine respiratory epithelial cells in vitro [9,12,14,15].…”

Lung epithelial cells have virus-specific and shared gene expression responses to infection by diverse respiratory viruses

“…Although susceptible mice mount a type I IFN response to PR8 infection, lethal infection is associated with spread of virus to the alveoli and an excessive inflammatory response [10-13]. PR8 replicates in bronchiolar and alveolar epithelial cells of the lower respiratory tract in vivo and in primary murine respiratory epithelial cells in vitro (Blazejewska et al, 2011; [9, 14, 15].…”