Synergistic Effects of Toll-Like Receptor 1/2 and Toll-Like Receptor 3 Signaling Triggering Interleukin 27 Gene Expression in Chikungunya Virus-Infected Macrophages.

Juan Felipe Valdés-López,Geysson J Fernandez,Silvio Urcuqui-Inchima

doi:10.3389/fcell.2022.812110

Juan Felipe Valdés-López, Geysson J Fernandez + Show 1 more

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https://doi.org/10.3389/fcell.2022.812110

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Abstract

Chikungunya virus (CHIKV) is the etiological agent of chikungunya fever (CHIKF), a self-limiting disease characterized by myalgia and severe acute or chronic arthralgia. CHIKF is associated with immunopathology and high levels of pro-inflammatory factors. CHIKV is known to have a wide range of tropism in human cell types, including keratinocytes, fibroblasts, endothelial cells, monocytes, and macrophages. Previously, we reported that CHIKV-infected monocytes-derived macrophages (MDMs) express high levels of interleukin 27 (IL27), a heterodimeric cytokine consisting of IL27p28 and EBI3 subunits, that triggers JAK-STAT signaling and promotes pro-inflammatory and antiviral response, in interferon (IFN)-independent manner. Based on the transcriptomic analysis, we now report that induction of IL27-dependent pro-inflammatory and antiviral response in CHIKV-infected MDMs relies on two signaling pathways: an early signal dependent on recognition of CHIKV-PAMPs by TLR1/2-MyD88 to activate NF-κB-complex that induces the expression of EBI3 mRNA; and second signaling dependent on the recognition of intermediates of CHIKV replication (such as dsRNA) by TLR3-TRIF, to activate IRF1 and the induction of IL27p28 mRNA expression. Both signaling pathways were required to produce a functional IL27 protein involved in the induction of ISGs, including antiviral proteins, cytokines, CC- and CXC- chemokines in an IFN-independent manner in MDMs. Furthermore, we reported that activation of TLR4 by LPS, both in human MDMs and murine BMDM, results in the induction of both subunits of IL27 that trigger strong IL27-dependent pro-inflammatory and antiviral response independent of IFNs signaling. Our findings are a significant contribution to the understanding of molecular and cellular mechanisms of CHIKV infection.

Highlights

1.1 Chikungunya VirusChikungunya virus (CHIKV) is a zoonotic arthropod-borne pathogen, a member of Alphavirus genus, Togaviridae family, that can cause significant public health threats with significant social and economic impact (Silva and Dermody 2017)
While IL27p28 reaches its peaked expression at 24 hpi, which correlated with the peak of CHIKV replication (R = 0.7414; p = 00,003), the peak of Epstein-Barr virus-induced 3 (EBI3) mRNA expression was observed at 6 hpi (Figure 1A)
Unlike to CHIKV wild type, UVCHIKV infection was unable to induce the expression of antiviral proteins (AVPs) in human monocytesderived macrophages (MDMs) at 24 hpi. These results suggest that induction of AVPs in CHIKV-infected MDMs, like TLR3 mRNA expression (Figure 5F) and interleukin 27 (IL27) protein production (Figure 5G), is dependent on active viral replication in infected MDMs.We reported earlier that stimulation of THP-1-derived macrophages activated Janus kinase (JAK)-STAT signaling and induced expression of STAT1-dependent pro-inflammatory factors, including cytokines such as IL7, IL15, TNF-related apoptosis-inducing ligand (TRAIL), and BAFF; CC- and CXC- chemokines, including CCL2, CCL5, CCL7, CCL8, CXCL9, CXCL10, and CXCL11 (Valdés-López et al, 2021)

Summary

Introduction

1.1 Chikungunya VirusChikungunya virus (CHIKV) is a zoonotic arthropod-borne pathogen, a member of Alphavirus genus, Togaviridae family, that can cause significant public health threats with significant social and economic impact (Silva and Dermody 2017). CHIKF is associated with the development of immunopathology linked to high levels of pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNFα), Interleukin (IL) 1β (IL1β), IL6, IL12p70, and IL15, both CCand CXC-chemokines (CCL2, CCL3, CCL5, CCL8, CXCL9, CXCL10, and CXCL11), both in CHIKV-infected patients and in vitro culture (Wauquier et al, 2011; Dupuis-Maguiraga et al, 2012; Gasque et al, 2015; Valdés-López et al, 2019). Among the cytokines/chemokines, IL1β, IL6, CCL5, and CCL8 are correlated with the severity of CHIKF, while others, including IL1Ra, IL12p70, IL16, IL17, IL18, CCL2, and CXCL10, are correlated with high CHIKV loads (Chow et al, 2011; Dupuis-Maguiraga et al, 2012); Cavalcanti et al (2019) reported that serum levels of IL27 were higher in patients with chronic CHIKF than in the ones with acute or subacute disease. High levels of IL27 correlate with the persistence of CHIKV-dependent arthralgia

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