H7N9 Influenza A Virus Exhibits Importin-α7-Mediated Replication in the Mammalian Respiratory Tract.
Bertram S, Thiele S, Dreier C, Resa-Infante P, Preuß A, van Riel D, Mok CK, Schwalm F, Peiris JS, Klenk HD, Gabriel G.
Am J Pathol. 2017 Feb 8. pii: S0002-9440(17)30067-6. doi: 10.1016/j.ajpath.2016.12.017. [Epub ahead of print]
Abstract
The acute respiratory distress syndrome (ARDS) is the leading cause of death in influenza
A virus (IAV)-infected patients. Hereby, the cellular importin-α7 gene
plays a major role. It promotes viral replication in the lung, thereby
increasing the risk for the development of pneumonia complicated by
ARDS.
Herein, we analyzed whether the recently emerged H7N9 avian IAV has already adapted to human importin-α7 use, which is associated with high-level virus replication in the mammalian lung.
Using a cell-based viral polymerase activity assay, we could detect a decreased H7N9 IAV polymerase activity when importin-α7 was silenced by siRNA.
Moreover, virus replication was diminished in the murine cells lacking the importin-α7 gene. Consistently, importin-α7 knockout mice presented reduced pulmonary virus titers and lung lesions as well as enhanced survival rates compared to wild-type mice.
In summary, our results show that H7N9 IAV have acquired distinct features of adaptation to human host factors that enable enhanced virulence in mammals. In particular, adaptation to human importin-α7 mediates elevated virus replication in the mammalian lung, which might have contributed to ARDS observed in H7N9-infected patients.
Herein, we analyzed whether the recently emerged H7N9 avian IAV has already adapted to human importin-α7 use, which is associated with high-level virus replication in the mammalian lung.
Using a cell-based viral polymerase activity assay, we could detect a decreased H7N9 IAV polymerase activity when importin-α7 was silenced by siRNA.
Moreover, virus replication was diminished in the murine cells lacking the importin-α7 gene. Consistently, importin-α7 knockout mice presented reduced pulmonary virus titers and lung lesions as well as enhanced survival rates compared to wild-type mice.
In summary, our results show that H7N9 IAV have acquired distinct features of adaptation to human host factors that enable enhanced virulence in mammals. In particular, adaptation to human importin-α7 mediates elevated virus replication in the mammalian lung, which might have contributed to ARDS observed in H7N9-infected patients.
Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.
- PMID:
- 28189564
- DOI:
- 10.1016/j.ajpath.2016.12.017
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