scholarly journals Myeloid Protease-Activated Receptor-2 Contributes to Influenza A Virus Pathology in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Randall C. Gunther ◽  
Vanthana Bharathi ◽  
Stephen D. Miles ◽  
Lauryn R. Tumey ◽  
Clare M. Schmedes ◽  
...  

BackgroundInnate immune responses to influenza A virus (IAV) infection are initiated in part by toll-like receptor 3 (TLR3). TLR3-dependent signaling induces an antiviral immune response and an NFκB-dependent inflammatory response. Protease-activated receptor 2 (PAR2) inhibits the antiviral response and enhances the inflammatory response. PAR2 deficiency protected mice during IAV infection. However, the PAR2 expressing cell-types contributing to IAV pathology in mice and the mechanism by which PAR2 contributes to IAV infection is unknown.MethodsIAV infection was analyzed in global (Par2-/-), myeloid (Par2fl/fl;LysMCre+) and lung epithelial cell (EpC) Par2 deficient (Par2fl/fl;SPCCre+) mice and their respective controls (Par2+/+ and Par2fl/fl). In addition, the effect of PAR2 activation on polyinosinic-polycytidylic acid (poly I:C) activation of TLR3 was analyzed in bone marrow-derived macrophages (BMDM). Lastly, we determined the effect of PAR2 inhibition in wild-type (WT) mice.ResultsAfter IAV infection, Par2-/- and mice with myeloid Par2 deficiency exhibited increased survival compared to infected controls. The improved survival was associated with reduced proinflammatory mediators and reduced cellular infiltration in bronchoalveolar lavage fluid (BALF) of Par2-/- and Par2fl/fl;LysMCre+ 3 days post infection (dpi) compared to infected control mice. Interestingly, Par2fl/fl;SPCCre+ mice showed no survival benefit compared to Par2fl/fl. In vitro studies showed that Par2-/- BMDM produced less IL6 and IL12p40 than Par2+/+ BMDM after poly I:C stimulation. In addition, activation of PAR2 on Par2+/+ BMDM increased poly I:C induction of IL6 and IL12p40 compared to poly I:C stimulation alone. Importantly, PAR2 inhibition prior to IAV infection protect WT mice.ConclusionGlobal Par2 or myeloid cell but not lung EpC Par2 deficiency was associated with reduced BALF inflammatory markers and reduced IAV-induced mortality. Our study suggests that PAR2 may be a therapeutic target to reduce IAV pathology.

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Xin Mao ◽  
Shuyin Gu ◽  
Huiting Sang ◽  
Yilu Ye ◽  
Jingyan Li ◽  
...  

Background. Luofushan-Baicao Oil (LBO) is an essential oil-rich traditional Chinese medicine (TCM) formula that is commonly used to treat cold, cough, headache, sore throat, swelling, and pain. However, the anti-influenza activities of LBO and the underlying mechanism remain to be investigated. Methods. The in vitro anti-influenza activity of LBO was tested with methyl thiazolyl tetrazolium (MTT) and plaque assays. The effects of LBO on the expressions of viral nucleoprotein and cytokines were evaluated. In the polyinosinic-polycytidylic acid- (Poly I: C-) induced inflammation model, the influences of LBO on the expression of cytokines and the activation of NF-κB P65 (P65) and interferon regulatory factor 3 (IRF3) were tested. After influenza A virus (IVA) infection, mice were administered with LBO for 5 days. The lung index, histopathologic change, the expression of viral protein, P65, and IRF3 in the lung tissue were measured. The levels of proinflammatory cytokines in serum were examined. Results. In vitro, LBO could significantly inhibit the infection of IVA, decrease the formation of plaques, and reduce the expression of viral nucleoprotein and cytokines. LBO could also effectively downregulate the expression of interleukin-1β (IL-1β), interleukin-6 (IL-6), and interferon-β and the activation of P65 and IRF3 in Poly I:C-treated cells. In the IVA-infected mice model, inhalation of LBO with atomizer could decrease the lung index, alleviate the pathological injury in the lung tissue, and reduce the serum levels of IL-1β and IL-6. LBO could significantly downregulate the expression of viral protein (nucleoprotein, PB2, and matrix 2 ion channel) and the phosphorylation of P65 and IRF3 in the lungs of mice. Conclusion. The therapeutic effects of LBO on treating influenza might result from the regulation of the immune response of IVA infection. LBO can be developed as an alternative therapeutic agent for influenza prevention.


Virology ◽  
2019 ◽  
Vol 537 ◽  
pp. 110-120 ◽  
Author(s):  
Shouping Zhang ◽  
Caiyun Huo ◽  
Jin Xiao ◽  
Tao Fan ◽  
Shumei Zou ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
You-Hui Tu ◽  
Yan Guo ◽  
Shuang Ji ◽  
Ji-Long Shen ◽  
Guang-He Fei

Background: Patients with chronic obstructive pulmonary disease (COPD) are more susceptible to influenza A virus (IAV) with more severe symptoms, yet the underlying molecular mechanisms of the hypersusceptibility of airway inflammatory response remain unclear.Methods: The primary human bronchial epithelial cells (pHBECs) were isolated from normal and COPD bronchial tissues (NHBE and DHBE) and cultured with/without IAV infection in vitro. DHBE cells were exposed to IAV for 24 h after knockdown of lncRNA TUG1 with short hairpin RNA (shRNA). Gain-of-function assays were performed with the miR-145-5p inhibitor and NF-κBp65 transfection. The expressions of lncRNA TUG1, miR-145-5p, phospho-NF-κBp65, NF-κBp65, TNF-α, and (Interleukin) IL-1β were examined with qRT-PCR, Western blotting, and ELISA. The interactions of lncRNA TUG1, miR-145-5p, and NF-κB were verified with luciferase reporter assay.Results: The expressions of lncRNA TUG1, phospho-NF-κBp65, TNF-α, and IL-1β were increased significantly in pHBECs after being infected with IAV for 24 h (all p0.05). The detailed time analysis revealed that the NF-κBp65 in DHBE was activated earlier than that in NHBE by Western blotting and immunofluorescence. Knockdown of lncRNA TUG1 and miR-145-5p mimic attenuated the expressions of NF-κBp65, TNF-α, and IL-1β significantly. The miR-145-5p inhibitor and NF-κBp65 transfection reversed the attenuated expressions of NF-κBp65, TNF-α, and IL-1β.Conclusion: The IAV causes the hypersusceptibility of airway inflammatory response, which may be closely associated with more severe symptoms in AECOPD patients. The lncRNA TUG1 inhibitor may be a promising therapeutic strategy for AECOPD caused by IAV.


2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Yunan Wei ◽  
Hao Zhou ◽  
Anqi Wang ◽  
Lipei Sun ◽  
Mingshu Wang ◽  
...  

The retinoic acid-inducible gene I (RIG-I) and the RIG-I-like receptor (RLR) protein play a critical role in the interferon (IFN) response during RNA virus infection. The tripartite motif containing 25 proteins (TRIM25) was reported to modify caspase activation and RIG-I recruitment domains (CARDs) via ubiquitin. These modifications allow TRIM25 to interact with mitochondrial antiviral signaling molecules (MAVs) and form CARD-CARD tetramers. Goose TRIM25 was cloned from gosling lungs, which possess a 1662 bp open reading flame (ORF). This ORF encodes a predicted 554 amino acid protein consisting of a B-box domain, a coiled-coil domain, and a PRY/SPRY domain. The protein sequence has 89.25% sequence identity withAnas platyrhynchosTRIM25, 78.57% withGallus gallusTRIM25, and 46.92% withHomo sapiensTRIM25. TRIM25 is expressed in all gosling and adult goose tissues examined. QRT-PCR revealed that goose TRIM25 transcription could be induced by goose IFN-α, goose IFN-γ, and goose IFN-λ, as well as a35 s polyinosinic-polycytidylic acid (poly(I:C)), oligodeoxynucleotides 2006 (ODN 2006), and resiquimod (R848) in vitro; however, it is inhibited in H9N2 infected goslings for unknown reasons. These data suggest that goose TRIM25 might play a positive role in the regulation of the antiviral immune response.


2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Georgia K. Atkin-Smith ◽  
Mubing Duan ◽  
Damien J. Zanker ◽  
Liyen Loh ◽  
Thi H. O. Nguyen ◽  
...  

AbstractThe disassembly of apoptotic cells into small membrane-bound vesicles termed apoptotic bodies (ApoBDs) is a hallmark of apoptosis; however, the functional significance of this process is not well defined. We recently discovered a new membrane protrusion (termed beaded apoptopodia) generated by apoptotic monocytes which fragments to release an abundance of ApoBDs. To investigate the function of apoptotic monocyte disassembly, we used influenza A virus (IAV) infection as a proof-of-concept model, as IAV commonly infects monocytes in physiological settings. We show that ApoBDs generated from IAV-infected monocytes contained IAV mRNA, protein and virions and consequently, could facilitate viral propagation in vitro and in vivo, and induce a robust antiviral immune response. We also identified an antipsychotic, Haloperidol, as an unexpected inhibitor of monocyte cell disassembly which could impair ApoBD-mediated viral propagation under in vitro conditions. Together, this study reveals a previously unrecognised function of apoptotic monocyte disassembly in the pathogenesis of IAV infections.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 509 ◽  
Author(s):  
Meenakshi Tiwary ◽  
Robert J. Rooney ◽  
Swantje Liedmann ◽  
Kim S. LeMessurier ◽  
Amali E. Samarasinghe

Eosinophils, previously considered terminally differentiated effector cells, have multifaceted functions in tissues. We previously found that allergic mice with eosinophil-rich inflammation were protected from severe influenza and discovered specialized antiviral effector functions for eosinophils including promoting cellular immunity during influenza. In this study, we hypothesized that eosinophil responses during the early phase of influenza contribute to host protection. Using in vitro and in vivo models, we found that eosinophils were rapidly and dynamically regulated upon influenza A virus (IAV) exposure to gain migratory capabilities to traffic to lymphoid organs after pulmonary infection. Eosinophils were capable of neutralizing virus upon contact and combinations of eosinophil granule proteins reduced virus infectivity through hemagglutinin inactivation. Bi-directional crosstalk between IAV-exposed epithelial cells and eosinophils occurred after IAV infection and cross-regulation promoted barrier responses to improve antiviral defenses in airway epithelial cells. Direct interactions between eosinophils and airway epithelial cells after IAV infection prevented virus-induced cytopathology in airway epithelial cells in vitro, and eosinophil recipient IAV-infected mice also maintained normal airway epithelial cell morphology. Our data suggest that eosinophils are important in the early phase of IAV infection providing immediate protection to the epithelial barrier until adaptive immune responses are deployed during influenza.


Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1301
Author(s):  
Ivonne Melano ◽  
Li-Lan Kuo ◽  
Yan-Chung Lo ◽  
Po-Wei Sung ◽  
Ni Tien ◽  
...  

Amino acids have been implicated with virus infection and replication. Here, we demonstrate the effects of two basic amino acids, arginine and lysine, and their ester derivatives on infection of two enveloped viruses, SARS-CoV-2, and influenza A virus. We found that lysine and its ester derivative can efficiently block infection of both viruses in vitro. Furthermore, the arginine ester derivative caused a significant boost in virus infection. Studies on their mechanism of action revealed that the compounds potentially disturb virus uncoating rather than virus attachment and endosomal acidification. Our findings suggest that lysine supplementation and the reduction of arginine-rich food intake can be considered as prophylactic and therapeutic regimens against these viruses while also providing a paradigm for the development of broad-spectrum antivirals.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 530
Author(s):  
Soo Jin Oh ◽  
Ok Sarah Shin

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) that has resulted in the current pandemic. The lack of highly efficacious antiviral drugs that can manage this ongoing global emergency gives urgency to establishing a comprehensive understanding of the molecular pathogenesis of SARS-CoV-2. We characterized the role of the nucleocapsid protein (N) of SARS-CoV-2 in modulating antiviral immunity. Overexpression of SARS-CoV-2 N resulted in the attenuation of retinoic acid inducible gene-I (RIG-I)-like receptor-mediated interferon (IFN) production and IFN-induced gene expression. Similar to the SARS-CoV-1 N protein, SARS-CoV-2 N suppressed the interaction between tripartate motif protein 25 (TRIM25) and RIG-I. Furthermore, SARS-CoV-2 N inhibited polyinosinic: polycytidylic acid [poly(I:C)]-mediated IFN signaling at the level of Tank-binding kinase 1 (TBK1) and interfered with the association between TBK1 and interferon regulatory factor 3 (IRF3), subsequently preventing the nuclear translocation of IRF3. We further found that both type I and III IFN production induced by either the influenza virus lacking the nonstructural protein 1 or the Zika virus were suppressed by the SARS-CoV-2 N protein. Our findings provide insights into the molecular function of the SARS-CoV-2 N protein with respect to counteracting the host antiviral immune response.


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