Sphingolipidomics of influenza A virus-infected Lung epithelial cells

Abstract

Introduction: Influenza virus continues to threaten humans and remains a global health concern. Influenza viruses hijack host cell machineries and impact host cell metabolism to tailor cellular pathways and resources to their needs for efficient replication, assembly and budding. Released viruses consist of a host-derived lipid envelope which is a detailed representation of the lipid composition at budding sites. They not only acquire such host lipids, but also have the capacity to actively remodel the lipid host landscape by tuning cellular sphingolipids and regulating different ceramide species. Gaining further insights into how host lipid remodeling occurs upon influenza A virus infection in human lung adenocarcinoma epithelial cell line and how they interfere with ceramide pathways might propose new avenues for development of antiviral molecules and strategies. Aims: To Establish a detailed lipid profile of infected A549 cell line infected with influenza A virus (IAV) and determine the impact of IAV infection on cellular sphingolipid metabolism. Methods: A549 were infected with IAV A/Puerto Rico/8/34 (PR8) at 1pfu/cell, and then harvested at different time points starting 15 minutes to 48 hours post-infection (hpi). Lipids were extracted and characterized using liquid chromatography-mass spectrometry (LC/MS/MS). Quantitative real-time PCR was performed to assess the expression levels of many key enzymes involved in the sphingolipid metabolic pathways. Results: IAV infection induced changes in host cell lipid metabolism leading to an increase in ceramide species in a time dependent manner marking the highest increase at 48 hpi compared to non-infected controls. IAV also induced an increase in lactosylceramide at later time points (36 and 48 hpi). Moreover, some sphingomyelin species were downregulated upon infection compared to non-infected cells at 36 hpi. Conclusion: IAV induces modifications in the A549 sphingolipidome. Ceramide exerts an antiviral role by inducing an accumulation at late time points.