Differential TLR-ERK1/2 Activity Promotes Viral SsRNA and DsRNA Mimic-Induced Dysregulated Immunity in Macrophages

Overview

Journal Pathogens

Date 2025 Jan 8

PMID 39770293

Authors

Rakshya Shrestha

Paige Marie Johnson

Roshan Ghimire

Cody John Whitley

Rudragouda Channappanavar

Affiliations

Soon will be listed here.

Abstract

RNA virus-induced excessive inflammation and impaired antiviral interferon (IFN-I) responses are associated with severe disease. This innate immune response, also referred to as "dysregulated immunity" is caused by viral single-stranded RNA (ssRNA)- and double-stranded-RNA (dsRNA)-mediated exuberant inflammation and viral protein-induced IFN antagonism. However, key host factors and the underlying mechanism driving viral RNA-mediated dysregulated immunity are poorly defined. Here, using viral ssRNA and dsRNA mimics, which activate toll-like receptor 7 (TLR7) and TLR3, respectively, we evaluated the role of viral RNAs in causing dysregulated immunity. We observed that murine bone marrow-derived macrophages (BMDMs), when stimulated with TLR3 and TLR7 agonists, induced differential inflammatory and antiviral cytokine response. TLR7 activation triggered a robust inflammatory cytokine/chemokine induction compared to TLR3 activation, whereas TLR3 stimulation induced significantly increased IFN/IFN stimulated gene (ISG) response relative to TLR7 activation. To define the mechanistic basis for dysregulated immunity, we examined cell-surface and endosomal TLR levels and downstream mitogen-activated protein kinase (MAPK) and nuclear factor kappa B (NF-kB) activation. We identified significantly higher cell-surface and endosomal TLR7 levels compared to TLR3, which were associated with early and robust MAPK (p-ERK1/2, p-P38, and p-JNK) and NF-kB activation in TLR7-stimulated macrophages. Furthermore, blocking EKR1/2 and NF-kB activity reduced TLR3/7-induced inflammatory cytokine/chemokine levels, whereas only ERK1/2 inhibition enhanced viral RNA mimic-induced IFN/ISG responses. Collectively, our results illustrate that high cell-surface and endosomal TLR7 expression and robust ERK1/2 activation drive viral ssRNA mimic-induced excessive inflammatory and reduced IFN/ISG response and blocking ERK1/2 activity would likely mitigate viral-RNA/TLR-induced dysregulated immunity.

References

Nelemans T, Kikkert M . Viral Innate Immune Evasion and the Pathogenesis of Emerging RNA Virus Infections. Viruses. 2019; 11(10). PMC: 6832425. DOI: 10.3390/v11100961. View

Lee J, Marshall J, Bowden D . Characterization of rubella virus replication complexes using antibodies to double-stranded RNA. Virology. 1994; 200(1):307-12. DOI: 10.1006/viro.1994.1192. View

Yamamoto M, Sato S, Mori K, Hoshino K, Takeuchi O, Takeda K . Cutting edge: a novel Toll/IL-1 receptor domain-containing adapter that preferentially activates the IFN-beta promoter in the Toll-like receptor signaling. J Immunol. 2002; 169(12):6668-72. DOI: 10.4049/jimmunol.169.12.6668. View

Franks T, Chong P, Chui P, Galvin J, Lourens R, Reid A . Lung pathology of severe acute respiratory syndrome (SARS): a study of 8 autopsy cases from Singapore. Hum Pathol. 2003; 34(8):743-8. PMC: 7119137. DOI: 10.1016/s0046-8177(03)00367-8. View

Reimann T, Buscher D, Hipskind R, Krautwald S, Lohmann-Matthes M, Baccarini M . Lipopolysaccharide induces activation of the Raf-1/MAP kinase pathway. A putative role for Raf-1 in the induction of the IL-1 beta and the TNF-alpha genes. J Immunol. 1994; 153(12):5740-9. View

Yoneyama M, Kikuchi M, Natsukawa T, Shinobu N, Imaizumi T, Miyagishi M . The RNA helicase RIG-I has an essential function in double-stranded RNA-induced innate antiviral responses. Nat Immunol. 2004; 5(7):730-7. DOI: 10.1038/ni1087. View

Lomas D, Lipson D, Miller B, Willits L, Keene O, Barnacle H . An oral inhibitor of p38 MAP kinase reduces plasma fibrinogen in patients with chronic obstructive pulmonary disease. J Clin Pharmacol. 2011; 52(3):416-24. DOI: 10.1177/0091270010397050. View

Kato H, Takeuchi O, Sato S, Yoneyama M, Yamamoto M, Matsui K . Differential roles of MDA5 and RIG-I helicases in the recognition of RNA viruses. Nature. 2006; 441(7089):101-5. DOI: 10.1038/nature04734. View

Flory E, Kunz M, Scheller C, Jassoy C, Stauber R, Rapp U . Influenza virus-induced NF-kappaB-dependent gene expression is mediated by overexpression of viral proteins and involves oxidative radicals and activation of IkappaB kinase. J Biol Chem. 2000; 275(12):8307-14. DOI: 10.1074/jbc.275.12.8307. View

10.

Zuo W, He D, Liang C, Du S, Hua Z, Nie Q . The persistence of SARS-CoV-2 in tissues and its association with long COVID symptoms: a cross-sectional cohort study in China. Lancet Infect Dis. 2024; 24(8):845-855. DOI: 10.1016/S1473-3099(24)00171-3. View

11.

Yamamoto M, Sato S, Hemmi H, Hoshino K, Kaisho T, Sanjo H . Role of adaptor TRIF in the MyD88-independent toll-like receptor signaling pathway. Science. 2003; 301(5633):640-3. DOI: 10.1126/science.1087262. View

12.

Fisk M, Cheriyan J, Mohan D, Forman J, Maki-Petaja K, Mceniery C . The p38 mitogen activated protein kinase inhibitor losmapimod in chronic obstructive pulmonary disease patients with systemic inflammation, stratified by fibrinogen: A randomised double-blind placebo-controlled trial. PLoS One. 2018; 13(3):e0194197. PMC: 5863984. DOI: 10.1371/journal.pone.0194197. View

13.

Phillip West A, Koblansky A, Ghosh S . Recognition and signaling by toll-like receptors. Annu Rev Cell Dev Biol. 2006; 22:409-37. DOI: 10.1146/annurev.cellbio.21.122303.115827. View

14.

Nichol S, Arikawa J, Kawaoka Y . Emerging viral diseases. Proc Natl Acad Sci U S A. 2000; 97(23):12411-2. PMC: 34064. DOI: 10.1073/pnas.210382297. View

15.

Taylor L, Latham S, Woolhouse M . Risk factors for human disease emergence. Philos Trans R Soc Lond B Biol Sci. 2001; 356(1411):983-9. PMC: 1088493. DOI: 10.1098/rstb.2001.0888. View

16.

Channappanavar R, Fehr A, Vijay R, Mack M, Zhao J, Meyerholz D . Dysregulated Type I Interferon and Inflammatory Monocyte-Macrophage Responses Cause Lethal Pneumonia in SARS-CoV-Infected Mice. Cell Host Microbe. 2016; 19(2):181-93. PMC: 4752723. DOI: 10.1016/j.chom.2016.01.007. View

17.

Saito T, Gale Jr M . Principles of intracellular viral recognition. Curr Opin Immunol. 2006; 19(1):17-23. DOI: 10.1016/j.coi.2006.11.003. View

18.

Deng X, Hackbart M, Mettelman R, OBrien A, Mielech A, Yi G . Coronavirus nonstructural protein 15 mediates evasion of dsRNA sensors and limits apoptosis in macrophages. Proc Natl Acad Sci U S A. 2017; 114(21):E4251-E4260. PMC: 5448190. DOI: 10.1073/pnas.1618310114. View

19.

Zhong B, Tien P, Shu H . Innate immune responses: crosstalk of signaling and regulation of gene transcription. Virology. 2006; 352(1):14-21. DOI: 10.1016/j.virol.2006.04.029. View

20.

Kato H, Sato S, Yoneyama M, Yamamoto M, Uematsu S, Matsui K . Cell type-specific involvement of RIG-I in antiviral response. Immunity. 2005; 23(1):19-28. DOI: 10.1016/j.immuni.2005.04.010. View