The nucleoprotein of influenza A virus inhibits the innate immune response by inducing mitophagy

Bo Zhang; Shuai Xu; Minxuan Liu; Yanli Wei; Qian Wang; Wentao Shen; Cao-Qi Lei; Qiyun Zhu

doi:10.1080/15548627.2022.2162798

The nucleoprotein of influenza A virus inhibits the innate immune response by inducing mitophagy

Autophagy. 2023 Jul;19(7):1916-1933. doi: 10.1080/15548627.2022.2162798. Epub 2023 Jan 1.

Authors

Bo Zhang^{1

2}, Shuai Xu¹, Minxuan Liu^{1

2}, Yanli Wei^{1

2}, Qian Wang¹, Wentao Shen¹, Cao-Qi Lei³, Qiyun Zhu^{1

2}

Affiliations

¹ State Key Laboratory of Veterinary Etiological Biology, College of Veterinary Medicine, Lanzhou University, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, PR China.
² College of Veterinary Medicine, Gansu Agricultural University, Lanzhou, PR China.
³ Hubei Key Laboratory of Cell Homeostasis, Frontier Science Center for Immunology and Metabolism, State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, PR China.

Abstract

Mitophagy is a form of autophagy that plays a key role in maintaining the homeostasis of functional mitochondria in the cell. Viruses have evolved various strategies to manipulate mitophagy to escape host immune responses and promote virus replication. In this study, the nucleoprotein (NP) of H1N1 virus (PR8 strain) was identified as a regulator of mitophagy. We revealed that NP-mediated mitophagy leads to the degradation of the mitochondria-anchored protein MAVS, thereby blocking MAVS-mediated antiviral signaling and promoting virus replication. The NP-mediated mitophagy is dependent on the interaction of NP with MAVS and the cargo receptor TOLLIP. Moreover, Y313 of NP is a key residue for the MAVS-NP interaction and NP-mediated mitophagy. The NP^Y313F mutation significantly attenuates the virus-induced mitophagy and the virus replication in vitro and in vivo. Taken together, our findings uncover a novel mechanism by which the NP of influenza virus induces mitophagy to attenuate innate immunity.Abbreviations: ACTB: actin beta; ATG7: autophagy related 7; ATG12: autophagy related 12; CCCP: carbonyl cyanide 3-chlorophenyl hydrazone; co-IP: co-immunoprecipitation; COX4/COXIV: cytochrome c oxidase subunit 4; DAPI: 4',6-diamidino-2-phenylindole, dihydrochloride; EID₅₀: 50% egg infective dose; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; HEK: human embryonic kidney; hpi: hours post-infection; IAV: influenza A virus; IFN: interferon; IP: immunoprecipitation; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAVS: mitochondrial antiviral signaling protein; Mdivi-1: mitochondrial division inhibitor 1; MLD₅₀: 50% mouse lethal dose; MOI: multiplicity of infection; NBR1: NBR1 autophagy cargo receptor; NP: nucleoprotein; PB1: basic polymerase 1; RFP: red fluorescent protein; RIGI: RNA sensor RIG-I; RIGI-N: RIGI-CARD; SeV: Sendai virus; SQSTM1/p62: sequestosome 1; TIMM23: translocase of inner mitochondrial membrane 23; TOLLIP: toll interacting protein; TOMM20: translocase of outer mitochondrial membrane 20; TUBA: tubulin alpha; Vec: empty vector; vRNP: viral ribonucleoprotein.

Keywords: Influenza A virus; MAVS; TOLLIP; mitophagy; nucleoprotein.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antiviral Agents / pharmacology
Autophagy
Humans
Immunity, Innate
Influenza A Virus, H1N1 Subtype*
Influenza A virus*
Mice
Mitophagy / genetics
Nucleoproteins / pharmacology

Substances

Nucleoproteins
3-(2,4-dichloro-5-methoxyphenyl)-2-sulfanyl-4(3H)-quinazolinone
Antiviral Agents

Grants and funding

This study was supported by funding from the National Key Research and Development Program of China (2021YFD1800204 to QZ), the National Natural Science Foundation of China (32172820 to SX; 31961133013 and 32272972 to QZ), and the Chinese Academy of Agricultural Science and Technology Innovation Project (CAAS-ASTIP-JBGS-20210102).