Toll-Like Receptor-3 Ligation-Induced Indoleamine 2, 3-Dioxygenase Expression in Human Trophoblasts

Indoleamine 2,3-dioxygenase (IDO) is an enzyme that degrades an essential amino acid, tryptophan, and plays a role in inhibiting the proliferation of T cells and intracellular pathogens. Inhibiting IDO in mice leads to fetal rejection, suggesting its significance in establishing pregnancy. Toll-like receptor 3 (TLR-3) is a key component of the innate immune system that recognizes viral double-stranded RNA and triggers immune reactions by producing type I interferon. Using a human trophoblast cell culture system, we studied the effect of TLR-3 ligation on IDO expression and function by treating trophoblasts with polyinosinic-polycytidylic acid [poly(I:C)] (a synthetic double stranded RNA, which mimics viral RNA). Real-time PCR and Western blot analysis revealed that IDO mRNA and protein expression was significantly induced by poly(I:C). The activity of IDO was also increased by poly(I:C) given that the l-kynurenine concentrations were elevated in conditioned media. Conditioned media from poly(I:C)-treated trophoblasts were found to inhibit the proliferation of human T cells significantly. Poly(I:C) was also shown to induce interferon (IFN)-β mRNA expression in trophoblasts. Recombinant human IFN-β increased IDO mRNA expression in trophoblasts more rapidly than poly(I:C). Pretreating with neutralizing antibody against IFN-β significantly suppressed IDO induction by poly(I:C). Collectively we have demonstrated that ligation of TLR-3 by poly(I:C) induces IDO expression in human first-trimester trophoblasts via an IFN-β-dependent pathway. These findings suggest that upon viral infection, trophoblasts induce IDO and in turn contribute to antimicrobial activity and maintenance of fetomaternal tolerance.

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HCFC2 is needed for IRF1- and IRF2-dependent Tlr3 transcription and for survival during viral infections

Journal of Experimental Medicine ◽

10.1084/jem.20161630 ◽

2017 ◽

Vol 214 (11) ◽

pp. 3263-3277 ◽

Cited By ~ 12

Author(s):

Lei Sun ◽

Zhengfan Jiang ◽

Victoria A. Acosta-Rodriguez ◽

Michael Berger ◽

Xin Du ◽

...

Keyword(s):

Viral Infections ◽

Poly I:C ◽

Type I ◽

Induced Mutations ◽

Herpes Simplex Virus 1 ◽

Double Stranded Rna ◽

Polycytidylic Acid ◽

Interferon Regulatory Factor 1 ◽

Mouse Macrophages ◽

Simplex Virus

Transcriptional regulation of numerous interferon-regulated genes, including Toll-like receptor 3 (Tlr3), which encodes an innate immune sensor of viral double-stranded RNA, depends on the interferon regulatory factor 1 (IRF1) and IRF2 transcription factors. We detected specific abrogation of macrophage responses to polyinosinic-polycytidylic acid (poly(I:C)) resulting from three independent N-ethyl-N-nitrosourea–induced mutations in host cell factor C2 (Hcfc2). Hcfc2 mutations compromised survival during influenza virus and herpes simplex virus 1 infections. HCFC2 promoted the binding of IRF1 and IRF2 to the Tlr3 promoter, without which inflammatory cytokine and type I IFN responses to the double-stranded RNA analogue poly(I:C) are reduced in mouse macrophages. HCFC2 was also necessary for the transcription of a large subset of other IRF2-dependent interferon-regulated genes. Deleterious mutations of Hcfc2 may therefore increase susceptibility to diverse infectious diseases.

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Innate immune responses through Toll-like receptor 3 require human-antigen-R-mediated Atp6v0d2 mRNA stabilization

Scientific Reports ◽

10.1038/s41598-019-56914-w ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Mohd Izwan Bin Zainol ◽

Takumi Kawasaki ◽

Warunthorn Monwan ◽

Motoya Murase ◽

Takuya Sueyoshi ◽

...

Keyword(s):

Immune Responses ◽

Innate Immune ◽

Poly I:C ◽

Type I ◽

Innate Immune Responses ◽

Toll Like Receptor ◽

Mrna Stabilization ◽

Human Antigen R ◽

Polycytidylic Acid ◽

Endosomal Acidification

AbstractToll-like receptor 3 (TLR3) recognizes double-stranded RNA derived from virus and its synthetic analogue, polyinosinic–polycytidylic acid [poly(I:C)]. Upon poly(I:C) binding, TLR3 activates transcription factors to express inflammatory cytokines and type I interferon. TLR3 is located in the endosomes and its recognition of poly(I:C) and activation of downstream signaling is regulated by endosomal acidification. However, the mechanism of post-transcriptional regulation in TLR3-mediated innate responses remains unclear. Here, we focused on Human antigen R (HuR, also known as ELAVL1) that recognizes and binds to the 3′ untranslated regions (3′UTRs) of target mRNAs, thereby protecting them from mRNA degradation, and found that HuR-deficient murine macrophage cells showed significantly reduced Ifnb1 mRNA expression after poly(I:C) stimulation. HuR-deficient cells also showed a marked reduction in the expression of Atp6v0d2 mRNA, which encodes a subunit of vacuolar-type H+ ATPase (V-ATPase), and therefore reduced endosomal acidification. HuR associated with the 3′UTR of Atp6v0d2 mRNA and the stability of Atp6v0d2 mRNA was maintained by its association with HuR. Taken together, our results suggest that HuR stabilizes Atp6v0d2 mRNA, which is required for the TLR3-mediated innate immune responses.

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Fc receptor γ-chain activation via hOSCAR induces survival and maturation of dendritic cells and modulates Toll-like receptor responses

Blood ◽

10.1182/blood-2004-07-2809 ◽

2005 ◽

Vol 105 (9) ◽

pp. 3623-3632 ◽

Cited By ~ 26

Author(s):

Estelle Merck ◽

Blandine de Saint-Vis ◽

Mathieu Scuiller ◽

Claude Gaillard ◽

Christophe Caux ◽

...

Keyword(s):

T Cells ◽

Fc Receptor ◽

Poly I:C ◽

Toll Like Receptor ◽

Phosphatidylinositol 3 Kinase ◽

Monocyte Chemoattractant Protein 1 ◽

Polycytidylic Acid ◽

Extracellular Signal ◽

Chemokine Ligand ◽

Human Osteoclast

AbstractWe previously reported the characterization of human osteoclast-associated receptor (hOSCAR), a novel Fc receptor γ-chain (FcRγ)–associated receptor expressed by myeloid cells. Here we show that ligation of hOSCAR by specific antibodies promotes dendritic cell (DC) survival by an extracellular signal-regulated kinase (ERK)- and phosphatidylinositol 3-kinase (PI3K)–dependent pathway, linked to expression of the Bcl-2 and Bcl-xL antiapoptotic molecules. Crosslinking of hOSCAR leads to maturation of DCs, as demonstrated by up-regulation of maturation markers, decrease in dextran uptake capacity, and secretion of immunesystem effectors such as interleukin-8 (IL-8)/CXC chemokine ligand 8 (CXCL8), IL-12 p40, monocyte chemoattractant protein-1 (MCP-1)/chemokine receptor ligand 2 (CCL2) and macrophage-derived chemokine (MDC)/CCL22. Stimulation of hOSCAR acts in conjunction with the Toll-like receptor (TLR) ligands, lipopolysaccharide (LPS), R-848, and polyinosinic-polycytidylic acid (poly(I:C)), to increase the expression of maturation markers, and to modulate cytokine release. A PI3K-dependent up-regulation of IL-10 release is observed with all the TLR ligands used, whereas regulation of IL-12 production is variable depending on the TLR stimulated. hOSCAR engagement on DCs did not significantly increase the proliferation of naive T cells; however, when co-incubated with TLR ligands, an enhanced proliferation was observed. The percentage of interferon (IFN)–γ–producing T cells is decreased when hOSCAR engagement is combined with LPS stimulation. Altogether, these data suggest that hOSCAR may modulate the responses of both innate resistance and adaptive immunity.

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SARS-CoV-2 Nucleocapsid Protein Targets RIG-I-Like Receptor Pathways to Inhibit the Induction of Interferon Response

Cells ◽

10.3390/cells10030530 ◽

2021 ◽

Vol 10 (3) ◽

pp. 530

Author(s):

Soo Jin Oh ◽

Ok Sarah Shin

Keyword(s):

Nucleocapsid Protein ◽

Nuclear Translocation ◽

Nonstructural Protein ◽

Poly I:C ◽

Interferon Response ◽

Type I ◽

Antiviral Immune Response ◽

N Protein ◽

Nonstructural Protein 1 ◽

Polycytidylic Acid

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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Abstract 095: CD74 Deficient Mice are Resistant to Toll-Like Receptor-Induced Preeclampsia

Hypertension ◽

10.1161/hyp.64.suppl_1.095 ◽

2014 ◽

Vol 64 (suppl_1) ◽

Author(s):

Mohamad Hatahet ◽

Olga Y Gasheva ◽

Valorie L Chiasson ◽

Piyali Chatterjee ◽

Kelsey R Bounds ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Endothelial Dysfunction ◽

Mhc Class Ii ◽

Immune Cells ◽

Immune Cell ◽

Class Ii ◽

Poly I:C ◽

Hypertensive Disorder ◽

Toll Like Receptor

Preeclampsia (PE) is a pregnancy-specific hypertensive disorder characterized by vascular endothelial dysfunction and excessive immunity and inflammation. Activation of the dsRNA receptor Toll-like receptor 3 (TLR3) or the ssRNA receptor TLR7 elicits a pregnancy-dependent PE-like syndrome in mice by inducing a pro-inflammatory immune response. CD74 (MHC Class II invariant chain) acts as a chaperone for MHC Class II surface expression on immune cells during antigen presentation and is cleaved into Class II-Associated Invariant Peptide (CLIP) following polyclonal activation of immune cell TLRs. The presence of CLIP in the groove of MHC Class II prevents T cell-dependent death leading to persistent immune cell activation. We hypothesized that genetic deletion of CD74 and subsequent depletion of CLIP on immune cells prevents TLR-induced immune responses and the development of PE in mice. Pregnant WT and CD74 KO mice were given i.p. injections of normal saline (P), poly I:C (TLR3 agonist; P-PIC), or R837 (TLR7 agonist; P-R837) on gestational days 13, 15, and 17 and euthanized on day 18. P-PIC and P-R837 WT mice had significantly increased splenic levels of pro-inflammatory CD3+/gd T cells and plasma levels of the gd T cell-derived cytokines IFNg, TNFa, and IL-17 compared to P WT mice whereas P-PIC and P-R837 CD74 KO mice had significantly increased anti-inflammatory CD3+/gd T cells and no significant increases in plasma IFNg, TNFa, and IL-17 levels. P-PIC and P-R837 CD74 KO mice did not develop the hypertension (gd17 SBP in mmHg: P WT=102±3, P CD74 KO=100±3, P-PIC WT=147±4*, P-PIC CD74 KO=95±3, P-R837 WT=133±2*, P-R837 CD74 KO=97±1; *p<0.05 vs. P WT), endothelial dysfunction, proteinuria, or placental necrosis seen in P-PIC and P-R837 WT mice. In conclusion, CD74 is crucial for the development of TLR-induced PE-like symptoms in mice and CD74/CLIP depletion may be a promising therapeutic target for women with PE.

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Autophagy Suppresses Toll-Like Receptor 3-Mediated Inflammatory Reaction in Human Epidermal Keratinocytes

BioMed Research International ◽

10.1155/2020/4584626 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Xue Mei Li ◽

Kyung Eun Jung ◽

Su Hyuk Yim ◽

Dong Kyun Hong ◽

Chang Deok Kim ◽

...

Keyword(s):

Inflammatory Reaction ◽

Skin Diseases ◽

Poly I:C ◽

Epidermal Keratinocytes ◽

Toll Like Receptor ◽

Inflammatory Skin Diseases ◽

Human Epidermal Keratinocytes ◽

Strong Light ◽

Polycytidylic Acid ◽

Inflammatory Skin

Autophagy, one mechanism of programmed cell death, is fundamental to cellular homeostasis. Previous studies have identified autophagy as a novel mechanism by which cytokines control the immune response. However, its precise role in immune-related inflammatory skin diseases such as psoriasis remains unclear. Thus, this study explored the functional role of autophagy in psoriatic inflammation of epidermal keratinocytes. Strong light chain 3 immunoreactivity was observed in epidermal keratinocytes of both human psoriatic lesions and imiquimod-induced mice psoriatic model, and it was readily induced by polycytidylic acid (poly (I:C)), which stimulates Toll-like receptor 3 (TLR3), in human epidermal keratinocytes in vitro. Rapamycin-induced activation of autophagy significantly reduced poly (I:C)-induced inflammatory reaction, whereas, inhibition of autophagy by 3-methyladeine increased that. Our results indicate that the induction of autophagy may attenuate TLR3-mediated immune responses in human epidermal keratinocytes, thus providing novel insights into the mechanisms underlying the development of inflammatory skin diseases including psoriasis.

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Synergistic benefit in inflammatory arthritis by targeting IκB kinase ϵ and interferon β

Annals of the Rheumatic Diseases ◽

10.1136/ard.2008.095356 ◽

2008 ◽

Vol 68 (2) ◽

pp. 257-263 ◽

Cited By ~ 28

Author(s):

M Corr ◽

D L Boyle ◽

L Ronacher ◽

N Flores ◽

G S Firestein

Keyword(s):

Gene Expression ◽

Low Dose ◽

Serum Levels ◽

Poly I:C ◽

Type I ◽

Wild Type ◽

Polycytidylic Acid ◽

Iκb Kinase ◽

Novel Approach ◽

Clinical Arthritis

Objectives:The IκB kinase (IKK)-related kinase IKKϵ regulates type I interferon expression and responses as well as proinflammatory mediator production. We examined the role of IKKϵ in arthritis and its ability to enhance the therapeutic response to systemic interferon (IFN) β therapy in passive murine K/BxN arthritis.Methods:IKKϵ–/–, IFNα∼βR–/– and wild type mice were given K/BxN serum and treated with polyinosinic polycytidylic acid (poly(I:C)), IFNβ, or normal saline. Clinical response and histological scores were assessed. Gene expression in the paws was measured by quantitative PCR. Serum interleukin 1a receptor agonist (IL1Ra) and IL10 were measured by ELISA and multiplex bead array.Results:Arthritis was almost completely blocked in wild type mice if arthritogenic K/BxN serum and the Toll-like receptor (TLR)3 ligand, poly(I:C), were coadministered at the onset of the model, but not in established disease. Mice deficient in IFNα∼βR had an accelerated course of arthritis, and did not respond to poly(I:C). IKKϵ null mice had a modest decrease in clinical arthritis compared with heterozygous mice. Low doses of IFNβ that were ineffective in wild type mice significantly decreased clinical arthritis in IKKϵ null mice. Articular chemokine gene expression was reduced in the IKKϵ–/– mice with arthritis and secreted IL1Ra (sIL1Ra) mRNA was significantly increased. Serum levels of IL1Ra were increased in low dose IFNβ-treated IKKϵ–/– mice.Conclusions:Subtherapeutic doses of IFNβ enhance the anti-inflammatory effects of IKKϵ deficiency, possibly by increasing production of IL1Ra and unmasking the antichemokine effects. Combination therapy with low dose IFNβ and an IKKϵ inhibitor might improve efficacy of either agent alone and offers a novel approach to RA.

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IL-6 Produced by Type I IFN DC Controls IFN-γ Production during the MLR by Blocking the Suppressive Effect of Regulatory T Cells.

Blood ◽

10.1182/blood.v104.11.3797.3797 ◽

2004 ◽

Vol 104 (11) ◽

pp. 3797-3797

Author(s):

Olivier Detournay ◽

Naima Mazouz ◽

Michel Goldman ◽

Michel Toungouz

Keyword(s):

T Cells ◽

Regulatory T Cells ◽

Mrna Level ◽

Suppressive Effect ◽

Poly I:C ◽

Type I ◽

Type I Ifn ◽

Effector Cells ◽

Gm Csf ◽

Ifn Γ

Abstract The dendritic cell family is composed of different subsets able to differentially govern the immune response. Their potent antigen presenting properties make them an attractive candidate for immunization against pathogens or cancer. In that setting, the recently characterized type I IFN DCs present interesting features including a higher expression of molecules involved in antigen presentation and the ability to trigger both the cellular and humoral arms of the immune responses. In view of the pivotal role of regulatory T cells in limiting the effectiveness of effector cells, we analyzed the interactions between these cells and type I IFN DC. DC generated from monocytes in the presence of IFN-β and IL-3 (DCI3) were activated by the maturation agent poly I:C and compared with the classical myeloid DC generated in the presence of GM-CSF and IL-4 (DCG4). Despite the release of lower amounts of IL-12 after maturation, DCI3 were able to induce a higher IFN-γ production by T lymphocytes during the MLR. Analysis at the mRNA level disclosed that DCI3 over transcribed the IL-6 gene leading to the release of high amounts of the protein both after the maturation process and during the MLR itself. Neutralization of IL-6 revealed that this cytokine specifically contributed to the IFN-γ release induced by DCI3. Finally, depletion of CD25+ T cells prior to the MLR identified these cells as a target for IL-6. We conclude from these results that DCI3 are endowed with the unique property of blocking the suppressive effect of regulatory T cells through high IL-6 production during the MLR. This novel mechanism of T cell control is relevant for the use of this DC type in vaccination strategies.

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