Direct Activation of Innate and Antigen-Presenting Functions of Microglia following Infection with Theiler's Virus

ABSTRACT Microglia are resident central nervous system (CNS) macrophages. Theiler's murine encephalomyelitis virus (TMEV) infection of SJL/J mice causes persistent infection of CNS microglia, leading to the development of a chronic-progressive CD4+ T-cell-mediated autoimmune demyelinating disease. We asked if TMEV infection of microglia activates their innate immune functions and/or activates their ability to serve as antigen-presenting cells for activation of T-cell responses to virus and endogenous myelin epitopes. The results indicate that microglia lines can be persistently infected with TMEV and that infection significantly upregulates the expression of cytokines involved in innate immunity (tumor necrosis factor alpha, interleukin-6 [IL-6], IL-18, and, most importantly, type I interferons) along with upregulation of major histocompatibility complex class II, IL-12, and various costimulatory molecules (B7-1, B7-2, CD40, and ICAM-1). Most significantly, TMEV-infected microglia were able to efficiently process and present both endogenous virus epitopes and exogenous myelin epitopes to inflammatory CD4+Th1 cells. Thus, TMEV infection of microglia activates these cells to initiate an innate immune response which may lead to the activation of naive and memory virus- and myelin-specific adaptive immune responses within the CNS.

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The Level of Viral Infection of Antigen-Presenting Cells Correlates with the Level of Development of Theiler's Murine Encephalomyelitis Virus-Induced Demyelinating Disease

Journal of Virology ◽

10.1128/jvi.02471-14 ◽

2014 ◽

Vol 89 (3) ◽

pp. 1867-1878 ◽

Cited By ~ 10

Author(s):

Young Hee Jin ◽

Hyun Seok Kang ◽

Wanqiu Hou ◽

Liping Meng ◽

Byung S. Kim

Keyword(s):

T Cell ◽

Immune Responses ◽

Viral Infection ◽

Demyelinating Disease ◽

Antigen Presenting Cells ◽

Cell Types ◽

Innate Immune ◽

Mhc Genes ◽

Encephalomyelitis Virus ◽

Antigen Presenting

ABSTRACTIntracerebral infection with Theiler's murine encephalomyelitis virus (TMEV) induces immune-mediated demyelinating disease in susceptible SJL/J mice but not in resistant C57BL/6 mice. Previous studies have indicated that the major histocompatibility complex (MHC) genes play the most prominent role in the development of TMEV-induced demyelinating disease. In this study, we used C57BL/6.S (B6.S) congenic mice, which carryH-2sMHC genes instead ofH-2bMHC genes in conjunction with the C57BL/6 (B6) background genes. Our data show that virus-infected B6.S mice are free from disease and have significantly lower viral loads than susceptible SJL mice, particularly in the spinal cord. A strong protective Th1-type T helper response with virtually no pathogenic Th17 response was detected in B6.S mice, in contrast to the reduced Th1- and robust Th17-type responses in SJL mice. Notably, lower levels of viral infectivity in B6.S antigen-presenting cells (APCs) correlated with the disease resistance and T-cell-type response.In vitrostudies using APCs from B6.S and SJL mice show that TLR2, -3, -4, and -7, but not TLR9, signaling can replace viral infection and augment the effect of viral infection in the differentiation of the pathogenic Th17 cell type. Taken together, these results strongly suggest that the viral replication levels in APCs critically affect the induction of protective versus pathogenic Th cell types via the signaling of pattern recognition receptors for innate immune responses. Our current findings further imply that the levels of viral infectivity/replication and TLR-mediated signaling play critical roles in the pathogenesis of chronic viral diseases.IMPORTANCEThis study indicates that innate immune cytokines produced in antigen-presenting cells stimulating the T cell immune responses during early viral infection play a critical role in determining the susceptibility of mice to the development of demyelinating disease. The level of innate immune cytokines reflects the level of initial viral infection in the antigen-presenting cells, and the level determines the development of T cell types, which are either protective or pathogenic. The level of initial viral infection to the cells is controlled by a gene or genes that are not associated with the major histocompatibility antigen complex genes. This finding has an important implication in controlling not only chronic viral infections but also infection-induced autoimmune-like diseases, which are closely associated with the pathogenic type of T cell responses.

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Effective Chemokine Secretion by Dendritic Cells and Expansion of Cross-Presenting CD4−/CD8+ Dendritic Cells Define a Protective Phenotype in the Mouse Model of Coxsackievirus Myocarditis

Journal of Virology ◽

10.1128/jvi.00047-08 ◽

2008 ◽

Vol 82 (16) ◽

pp. 8149-8160 ◽

Cited By ~ 42

Author(s):

Andreas Oliver Weinzierl ◽

Gudrun Szalay ◽

Hartwig Wolburg ◽

Martina Sauter ◽

Hans-Georg Rammensee ◽

...

Keyword(s):

Dendritic Cells ◽

T Cell ◽

Acute Myocarditis ◽

Type I Interferons ◽

Mouse Strains ◽

Type I ◽

Necrosis Factor Alpha ◽

Chronic Myocarditis ◽

Cvb3 Infection

ABSTRACT Enteroviruses such as coxsackievirus B3 (CVB3) are able to induce lethal acute and chronic myocarditis. In resistant C57BL/6 mice, CVB3 myocarditis is abrogated by T-cell-dependent mechanisms, whereas major histocompatibility complex (MHC)-matched permissive A.BY/SnJ mice develop chronic myocarditis based on virus persistence. To define the role of T-cell-priming dendritic cells (DCs) in the outcome of CVB3 myocarditis, DCs were analyzed in this animal model in the course of CVB3 infection. In both mouse strains, DCs were found to be infectible with CVB3; however, formation of infectious virions was impaired. In DCs derived from C57BL/6 mice, significantly higher quantities of interleukin-10 (IL-10) and the proinflammatory cytokines IL-6 and tumor necrosis factor alpha were measured compared to those from A.BY/SnJ mice. Additionally, the chemokines interferon-inducible protein 10 (IP-10) and RANTES were secreted by DCs from resistant C57BL/6 mice earlier in infection and at significantly higher levels. The protective role of IP-10 in CVB3 myocarditis was confirmed in IP-10−/− mice, which had increased myocardial injury compared to the immunocompetent control animals. Also, major differences in resistant and permissive mice were found in DC subsets, with C57BL/6 mice harboring more cross-priming CD4− CD8+ DCs. As CD4− CD8+ DCs are known to express 10 times more Toll-like receptor 3 (TLR3) than other DC subsets, we followed the course of CVB3 infection in TLR3−/− mice. These mice developed a fulminant acute myocarditis and secreted sustained low amounts of type I interferons; secretion of IP-10 and RANTES was nearly abrogated in DCs. We conclude that MHC-independent genetic factors involving DC-related IP-10 secretion and TLR3 expression are beneficial in the prevention of chronic coxsackievirus myocarditis.

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Exosomes Secreted by Microglia During Virus Infection in the Central Nervous System Activate an Inflammatory Response in Bystander Cells

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.661935 ◽

2021 ◽

Vol 9 ◽

Author(s):

Nhungoc Luong ◽

Julie K. Olson

Keyword(s):

Central Nervous System ◽

Immune Response ◽

Nervous System ◽

Demyelinating Disease ◽

Innate Immune ◽

Viral Rna ◽

Type I Interferons ◽

Type I ◽

The Central Nervous System ◽

Bystander Cells

Microglia become persistently infected during Theiler’s murine encephalomyelitis virus (TMEV) infection in the central nervous system (CNS) of susceptible mice. We have previously shown that microglia infected with TMEV become activated through the innate immune receptors to express type I interferons, cytokines, and chemokines. Persistent TMEV infection in the CNS promotes chronic neuroinflammation and development of demyelinating disease similar to multiple sclerosis. In the current studies, we wanted to determine whether TMEV-infected microglia secrete exosomes which contribute to neuroinflammation in the CNS thus promoting the development of demyelinating disease. Exosomes are vesicles containing RNA, DNA, and proteins that are released from one cell and taken up by another cell to facilitate communication between cells. These studies isolated exosomes secreted by microglia during TMEV infection in vitro as well as exosomes secreted by microglia during early TMEV infection in mice. These studies show that microglia secrete exosomes during TMEV infection which contain the viral RNA coding region. The exosomes secreted by microglia during TMEV infection can be taken up by uninfected bystander cells, including CNS resident microglia, astrocytes, and neurons. The viral RNA in the exosomes can be transferred to the bystander cells. In addition, the bystander cells that took up these exosomes were activated through the innate immune response to express type I interferons, IFNα and IFNβ, pro-inflammatory cytokines, IL-6, IL-12, and TNFα, and chemokines, CCL2. Most interestingly, exosomes secreted by microglia during early TMEV infection in mice activated an inflammatory response when transferred to the brains of naïve mice. These results show that exosomes secreted by microglia during early TMEV infection contain viral RNA and can activate uninfected bystander CNS cells to promote an inflammatory immune response. Thus, exosomes secreted by microglia during virus infection may promote viral persistence and neuroinflammation which contributes to the development of demyelinating disease.

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Review for "Type I interferons are important co‐stimulatory signals during T cell receptor mediated human MAIT cell activation"

10.1002/eji.201948279/v2/review2 ◽

2019 ◽

Keyword(s):

T Cell ◽

T Cell Receptor ◽

Cell Activation ◽

Cell Receptor ◽

Type I Interferons ◽

Type I ◽

Mait Cell

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Faculty Opinions recommendation of Type I interferons directly inhibit regulatory T cells to allow optimal antiviral T cell responses during acute LCMV infection.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.718342706.793494594 ◽

2014 ◽

Author(s):

Thomas Huenig

Keyword(s):

T Cells ◽

T Cell ◽

Regulatory T Cells ◽

T Cell Responses ◽

Type I Interferons ◽

Type I ◽

Cell Responses ◽

Lcmv Infection

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Type I interferons affect the metabolic fitness of CD8+ T cells from patients with systemic lupus erythematosus

Nature Communications ◽

10.1038/s41467-021-22312-y ◽

2021 ◽

Vol 12 (1) ◽

Cited By ~ 1

Author(s):

Norzawani Buang ◽

Lunnathaya Tapeng ◽

Victor Gray ◽

Alessandro Sardini ◽

Chad Whilding ◽

...

Keyword(s):

Systemic Lupus Erythematosus ◽

T Cells ◽

Cell Death ◽

T Cell ◽

Lupus Erythematosus ◽

Type I Interferons ◽

Type I ◽

Type I Ifn ◽

Systemic Lupus ◽

Mitochondrial Abnormalities

AbstractThe majority of patients with systemic lupus erythematosus (SLE) have high expression of type I IFN-stimulated genes. Mitochondrial abnormalities have also been reported, but the contribution of type I IFN exposure to these changes is unknown. Here, we show downregulation of mitochondria-derived genes and mitochondria-associated metabolic pathways in IFN-High patients from transcriptomic analysis of CD4+ and CD8+ T cells. CD8+ T cells from these patients have enlarged mitochondria and lower spare respiratory capacity associated with increased cell death upon rechallenge with TCR stimulation. These mitochondrial abnormalities can be phenocopied by exposing CD8+ T cells from healthy volunteers to type I IFN and TCR stimulation. Mechanistically these ‘SLE-like’ conditions increase CD8+ T cell NAD+ consumption resulting in impaired mitochondrial respiration and reduced cell viability, both of which can be rectified by NAD+ supplementation. Our data suggest that type I IFN exposure contributes to SLE pathogenesis by promoting CD8+ T cell death via metabolic rewiring.

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Bacterial Cyclic Dinucleotides and the cGAS–cGAMP–STING Pathway: A Role in Periodontitis?

Pathogens ◽

10.3390/pathogens10060675 ◽

2021 ◽

Vol 10 (6) ◽

pp. 675

Author(s):

Samira Elmanfi ◽

Mustafa Yilmaz ◽

Wilson W. S. Ong ◽

Kofi S. Yeboah ◽

Herman O. Sintim ◽

...

Keyword(s):

Immune Response ◽

Periodontal Disease ◽

Innate Immune ◽

Host Cells ◽

Type I Interferons ◽

Type I ◽

Vaccine Adjuvants ◽

Cyclic Dinucleotides ◽

Sting Pathway

Host cells can recognize cytosolic double-stranded DNAs and endogenous second messengers as cyclic dinucleotides—including c-di-GMP, c-di-AMP, and cGAMP—of invading microbes via the critical and essential innate immune signaling adaptor molecule known as STING. This recognition activates the innate immune system and leads to the production of Type I interferons and proinflammatory cytokines. In this review, we (1) focus on the possible role of bacterial cyclic dinucleotides and the STING/TBK1/IRF3 pathway in the pathogenesis of periodontal disease and the regulation of periodontal immune response, and (2) review and discuss activators and inhibitors of the STING pathway as immune response regulators and their potential utility in the treatment of periodontitis. PubMed/Medline, Scopus, and Web of Science were searched with the terms “STING”, “TBK 1”, “IRF3”, and “cGAS”—alone, or together with “periodontitis”. Current studies produced evidence for using STING-pathway-targeting molecules as part of anticancer therapy, and as vaccine adjuvants against microbial infections; however, the role of the STING/TBK1/IRF3 pathway in periodontal disease pathogenesis is still undiscovered. Understanding the stimulation of the innate immune response by cyclic dinucleotides opens a new approach to host modulation therapies in periodontology.

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