Quantitative Subcellular Proteome and Secretome Profiling of Influenza A Virus-Infected Human Primary Macrophages

Niina Lietzén,Sampsa Matikainen,Tero Aittokallio,Johanna Rintahaka,Tiina Öhman,Tuula A Nyman,Ilkka Julkunen,Akiko Iwasaki

doi:10.1371/journal.ppat.1001340

Abstract

Influenza A viruses are important pathogens that cause acute respiratory diseases and annual epidemics in humans. Macrophages recognize influenza A virus infection with their pattern recognition receptors, and are involved in the activation of proper innate immune response. Here, we have used high-throughput subcellular proteomics combined with bioinformatics to provide a global view of host cellular events that are activated in response to influenza A virus infection in human primary macrophages. We show that viral infection regulates the expression and/or subcellular localization of more than one thousand host proteins at early phases of infection. Our data reveals that there are dramatic changes in mitochondrial and nuclear proteomes in response to infection. We show that a rapid cytoplasmic leakage of lysosomal proteins, including cathepsins, followed by their secretion, contributes to inflammasome activation and apoptosis seen in the infected macrophages. Also, our results demonstrate that P2X7 receptor and src tyrosine kinase activity are essential for inflammasome activation during influenza A virus infection. Finally, we show that influenza A virus infection is associated with robust secretion of different danger-associated molecular patterns (DAMPs) suggesting an important role for DAMPs in host response to influenza A virus infection. In conclusion, our high-throughput quantitative proteomics study provides important new insight into host-response against influenza A virus infection in human primary macrophages.

Highlights

Influenza A viruses are negative-stranded RNA viruses that are capable of infecting a variety of avian and mammalian species
For subcellular proteome and secretome analysis (Fig. 1A) human primary macrophages were first infected with influenza A virus for 6 h, 12 h and 18 h or 6 h, 9 h and 12 h
Based on the LC-mass spectrometry (MS)/MS data we identified 1999, 1423, 1230 and 627 proteins from the mitochondrial, cytoplasmic and nuclear cell fractions and secretome, respectively, with false discovery rates (FDR) of the sample sets varying from 0.5 to 1.6%

Summary

Introduction

Influenza A viruses are negative-stranded RNA viruses that are capable of infecting a variety of avian and mammalian species. These viruses are responsible for the annual epidemics that cause severe illnesses in millions of people worldwide. The principal effector cells involved in innate immunity are macrophages, and dendritic cells (DC) that kill microbes through phagocytosis, present antigens to T cells, and produce cytokines. These innate immune responses are essential for the development of later adaptive immune responses, which provide specific cell-mediated and humoral protection, and are often necessary for a complete clearance of infection

Methods

Results

Conclusion