pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.

Inflammatory factors and type I interferons (IFNs) are key components of host antiviral innate immune responses, which can be released from the pathogen-infected macrophages. African swine fever virus (ASFV) has developed various strategies to evade host antiviral innate immune responses, including...

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Main Authors: Jiangnan Li, Jie Song, Li Kang, Li Huang, Shijun Zhou, Liang Hu, Jun Zheng, Changyao Li, Xianfeng Zhang, Xijun He, Dongming Zhao, Zhigao Bu, Changjiang Weng
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2021-07-01
Series:PLoS Pathogens
Online Access:https://doi.org/10.1371/journal.ppat.1009733
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author Jiangnan Li
Jie Song
Li Kang
Li Huang
Shijun Zhou
Liang Hu
Jun Zheng
Changyao Li
Xianfeng Zhang
Xijun He
Dongming Zhao
Zhigao Bu
Changjiang Weng
author_facet Jiangnan Li
Jie Song
Li Kang
Li Huang
Shijun Zhou
Liang Hu
Jun Zheng
Changyao Li
Xianfeng Zhang
Xijun He
Dongming Zhao
Zhigao Bu
Changjiang Weng
author_sort Jiangnan Li
collection DOAJ
description Inflammatory factors and type I interferons (IFNs) are key components of host antiviral innate immune responses, which can be released from the pathogen-infected macrophages. African swine fever virus (ASFV) has developed various strategies to evade host antiviral innate immune responses, including alteration of inflammatory responses and IFNs production. However, the molecular mechanism underlying inhibition of inflammatory responses and IFNs production by ASFV-encoded proteins has not been fully understood. Here we report that ASFV infection only induced low levels of IL-1β and type I IFNs in porcine alveolar macrophages (PAMs), even in the presence of strong inducers such as LPS and poly(dA:dT). Through further exploration, we found that several members of the multigene family 360 (MGF360) and MGF505 strongly inhibited IL-1β maturation and IFN-β promoter activation. Among them, pMGF505-7R had the strongest inhibitory effect. To verify the function of pMGF505-7R in vivo, a recombinant ASFV with deletion of the MGF505-7R gene (ASFV-Δ7R) was constructed and assessed. As we expected, ASFV-Δ7R infection induced higher levels of IL-1β and IFN-β compared with its parental ASFV HLJ/18 strain. ASFV infection-induced IL-1β production was then found to be dependent on TLRs/NF-κB signaling pathway and NLRP3 inflammasome. Furthermore, we demonstrated that pMGF505-7R interacted with IKKα in the IKK complex to inhibit NF-κB activation and bound to NLRP3 to inhibit inflammasome formation, leading to decreased IL-1β production. Moreover, we found that pMGF505-7R interacted with and inhibited the nuclear translocation of IRF3 to block type I IFN production. Importantly, the virulence of ASFV-Δ7R is reduced in piglets compared with its parental ASFV HLJ/18 strain, which may due to induction of higher IL-1β and type I IFN production in vivo. Our findings provide a new clue to understand the functions of ASFV-encoded pMGF505-7R and its role in viral infection-induced pathogenesis, which might help design antiviral agents or live attenuated vaccines to control ASF.
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spelling doaj.art-b6730bb6b316491196589867e2b851362022-12-21T18:11:03ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742021-07-01177e100973310.1371/journal.ppat.1009733pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.Jiangnan LiJie SongLi KangLi HuangShijun ZhouLiang HuJun ZhengChangyao LiXianfeng ZhangXijun HeDongming ZhaoZhigao BuChangjiang WengInflammatory factors and type I interferons (IFNs) are key components of host antiviral innate immune responses, which can be released from the pathogen-infected macrophages. African swine fever virus (ASFV) has developed various strategies to evade host antiviral innate immune responses, including alteration of inflammatory responses and IFNs production. However, the molecular mechanism underlying inhibition of inflammatory responses and IFNs production by ASFV-encoded proteins has not been fully understood. Here we report that ASFV infection only induced low levels of IL-1β and type I IFNs in porcine alveolar macrophages (PAMs), even in the presence of strong inducers such as LPS and poly(dA:dT). Through further exploration, we found that several members of the multigene family 360 (MGF360) and MGF505 strongly inhibited IL-1β maturation and IFN-β promoter activation. Among them, pMGF505-7R had the strongest inhibitory effect. To verify the function of pMGF505-7R in vivo, a recombinant ASFV with deletion of the MGF505-7R gene (ASFV-Δ7R) was constructed and assessed. As we expected, ASFV-Δ7R infection induced higher levels of IL-1β and IFN-β compared with its parental ASFV HLJ/18 strain. ASFV infection-induced IL-1β production was then found to be dependent on TLRs/NF-κB signaling pathway and NLRP3 inflammasome. Furthermore, we demonstrated that pMGF505-7R interacted with IKKα in the IKK complex to inhibit NF-κB activation and bound to NLRP3 to inhibit inflammasome formation, leading to decreased IL-1β production. Moreover, we found that pMGF505-7R interacted with and inhibited the nuclear translocation of IRF3 to block type I IFN production. Importantly, the virulence of ASFV-Δ7R is reduced in piglets compared with its parental ASFV HLJ/18 strain, which may due to induction of higher IL-1β and type I IFN production in vivo. Our findings provide a new clue to understand the functions of ASFV-encoded pMGF505-7R and its role in viral infection-induced pathogenesis, which might help design antiviral agents or live attenuated vaccines to control ASF.https://doi.org/10.1371/journal.ppat.1009733
spellingShingle Jiangnan Li
Jie Song
Li Kang
Li Huang
Shijun Zhou
Liang Hu
Jun Zheng
Changyao Li
Xianfeng Zhang
Xijun He
Dongming Zhao
Zhigao Bu
Changjiang Weng
pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.
PLoS Pathogens
title pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.
title_full pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.
title_fullStr pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.
title_full_unstemmed pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.
title_short pMGF505-7R determines pathogenicity of African swine fever virus infection by inhibiting IL-1β and type I IFN production.
title_sort pmgf505 7r determines pathogenicity of african swine fever virus infection by inhibiting il 1β and type i ifn production
url https://doi.org/10.1371/journal.ppat.1009733
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