Lung epithelial PDIA3 plays a critical role in influenza infection

Abstract

RATIONALEThe influenza A virus (IAV) causes severe respiratory illness in humans. Current treatments are rapidly becoming ineffective due to the emergence of viral resistance to available therapies. Given the impact of IAV on human health and health care costs there is an urgent need to explore novel targets for treatments to control IAV. Previous work has demonstrated infection with IAV induces endoplasmic reticulum (ER) stress, effectuating the unfolded protein response (UPR), a highly conserved cellular stress response that seeks to restore normal ER homeostasis. It has also been shown that interactions with host ER based protein disulfide isomerases (PDIs) are upregulated during the UPR and are required for specific IAV proteins to reach their functional conformations in vitro. The viral proteins hemagglutinin (HA) and neuraminidase (NA) both contain numerous disulfide bonds necessary for their function. Our results demonstrate both HA and NA interact with PDIA3; a chaperone responsible for the catalysis and isomerization of disulfide bonds. However it is unknown whether these host‐viral protein interactions are required during active infection in vivo and whether PDIA3 represents a putative therapeutic target during H1N1 infection.OBJECTIVETo investigate the role of host PDIA3 in the establishment of H1N1 infection and development of subsequent immunopathology.METHODSThe impact of PDIA3 in IAV infection was examined using lung epithelial specific PDIA3 knockout mice and various inhibitors of PDIs in isolated primary mouse tracheal epithelial cells (MTEC).RESULTSWe found that the conditional deletion of PDIA3 in our mouse model resulted in a significant decrease in the number of inflammatory‐immune cells in bronchoalveolar lavage fluid and a marked decrease in IAV‐mediated methacholine induced airway hyperresponsivness, illustrating that PDIA3 plays a significant role in influenza‐induced immunopathology. Interestingly, our data further show that deletion of PDIA3 in vivo affected production of IAV proteins HA and NA. Moreover, We also observed significant alterations in the oxidative folding of HA as well as decreases in IAV induced proinflammatory cytokines in MTECs treated with the PDI inhibitors in vitro.CONCLUSIONSThese data suggest that lung epithelial PDIA3 plays a critical role in the establishment of IAV infection and propagation of the virus, and illustrate the potential of utilizing PDIA3 as a target for future anti‐viral therapies.Support or Funding InformationNIH R01 HL12238 (VA) NIH T32 HL076122 (NC) Department of Pathology and Laboratory Medicine (UVM) Startup Fund (VA)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.