scholarly journals Alphaherpesvirus-induced activation of plasmacytoid dendritic cells depends on the viral glycoprotein gD and is inhibited by non-infectious light particles

2021 ◽  
Vol 17 (11) ◽  
pp. e1010117
Author(s):  
Jonas L. Delva ◽  
Cliff Van Waesberghe ◽  
Barbara G. Klupp ◽  
Thomas C. Mettenleiter ◽  
Herman W. Favoreel
Keyword(s):  
Dendritic Cells ◽  
Pseudorabies Virus ◽  
Viral Infections ◽  
Critical Role ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
Viral Glycoprotein ◽  
Dna Viruses ◽  
Endosomal Acidification ◽  
Simplex Virus

Plasmacytoid dendritic cells (pDC) are important innate immune cells during the onset of viral infections as they are specialized in the production of massive amounts of antiviral type I interferon (IFN). Alphaherpesviruses such as herpes simplex virus (HSV) or pseudorabies virus (PRV) are double stranded DNA viruses and potent stimulators of pDC. Detailed information on how PRV activates porcine pDC is lacking. Using PRV and porcine primary pDC, we report here that PRV virions, so-called heavy (H-)particles, trigger IFNα production by pDC, whereas light (L-) particles that lack viral DNA and capsid do not. Activation of pDC requires endosomal acidification and, importantly, depends on the PRV gD envelope glycoprotein and O-glycosylations. Intriguingly, both for PRV and HSV-1, we found that L-particles suppress H-particle-mediated activation of pDC, a process which again depends on viral gD. This is the first report describing that gD plays a critical role in alphaherpesvirus-induced pDC activation and that L-particles directly interfere with alphaherpesvirus-induced IFNα production by pDC.

scholarly journals High Secretion of Interferons by Human Plasmacytoid Dendritic Cells upon Recognition of Middle East Respiratory Syndrome Coronavirus

2015 ◽  
Vol 89 (7) ◽  
pp. 3859-3869 ◽  
Author(s):  
Vivian A. Scheuplein ◽  
Janna Seifried ◽  
Anna H. Malczyk ◽  
Lilija Miller ◽  
Lena Höcker ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Middle East ◽  
Respiratory Disease ◽  
Immune Cell ◽  
Critical Role ◽  
Plasmacytoid Dendritic Cells ◽  
Middle East Respiratory Syndrome ◽  
Early Gene ◽  
Type I ◽  
Endosomal Uptake

ABSTRACTThe Middle East respiratory syndrome coronavirus (MERS-CoV) emerged in 2012 as the causative agent of a severe respiratory disease with a fatality rate of approximately 30%. The high virulence and mortality rate prompted us to analyze aspects of MERS-CoV pathogenesis, especially its interaction with innate immune cells such as antigen-presenting cells (APCs). Particularly, we analyzed secretion of type I and type III interferons (IFNs) by APCs, i.e., B cells, macrophages, monocyte-derived/myeloid dendritic cells (MDDCs/mDCs), and by plasmacytoid dendritic cells (pDCs) of human and murine origin after inoculation with MERS-CoV. Production of large amounts of type I and III IFNs was induced exclusively in human pDCs, which were significantly higher than IFN induction by severe acute respiratory syndrome (SARS)-CoV. Of note, IFNs were secreted in the absence of productive replication. However, receptor binding, endosomal uptake, and probably signaling via Toll-like receptor 7 (TLR7) were critical for sensing of MERS-CoV by pDCs. Furthermore, active transcription of MERS-CoV N RNA and subsequent N protein expression were evident in infected pDCs, indicating abortive infection. Taken together, our results point toward dipeptidyl peptidase 4 (DPP4)-dependent endosomal uptake and subsequent infection of human pDCs by MERS-CoV. However, the replication cycle is stopped after early gene expression. In parallel, human pDCs are potent IFN-producing cells upon MERS-CoV infection. Knowledge of such IFN responses supports our understanding of MERS-CoV pathogenesis and is critical for the choice of treatment options.IMPORTANCEMERS-CoV causes a severe respiratory disease with high fatality rates in human patients. Recently, confirmed human cases have increased dramatically in both number and geographic distribution. Understanding the pathogenesis of this highly pathogenic CoV is crucial for developing successful treatment strategies. This study elucidates the interaction of MERS-CoV with APCs and pDCs, particularly the induction of type I and III IFN secretion. Human pDCs are the immune cell population sensing MERS-CoV but secrete significantly larger amounts of IFNs, especially IFN-α, than in response to SARS-CoV. A model for molecular virus-host interactions is presented outlining IFN induction in pDCs. The massive IFN secretion upon contact suggests a critical role of this mechanism for the high degree of immune activation observed during MERS-CoV infection.

scholarly journals Identification of poly(ADP-ribose) polymerase 9 (PARP9) as a noncanonical sensor for RNA virus in dendritic cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Junji Xing ◽  
Ao Zhang ◽  
Yong Du ◽  
Mingli Fang ◽  
Laurie J. Minze ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Protective Immunity ◽  
Viral Infections ◽  
Rna Virus ◽  
Critical Role ◽  
Innate Immune ◽  
Type I ◽  
Type I Ifn ◽  
Mitochondrial Antiviral Signaling ◽  
Phosphoinositide 3 Kinase

AbstractInnate immune cells are critical in protective immunity against viral infections, involved in sensing foreign viral nucleic acids. Here we report that the poly(ADP-ribose) polymerase 9 (PARP9), a member of PARP family, serves as a non-canonical sensor for RNA virus to initiate and amplify type I interferon (IFN) production. We find knockdown or deletion of PARP9 in human or mouse dendritic cells and macrophages inhibits type I IFN production in response to double strand RNA stimulation or RNA virus infection. Furthermore, mice deficient for PARP9 show enhanced susceptibility to infections with RNA viruses because of the impaired type I IFN production. Mechanistically, we show that PARP9 recognizes and binds viral RNA, with resultant recruitment and activation of the phosphoinositide 3-kinase (PI3K) and AKT3 pathway, independent of mitochondrial antiviral-signaling (MAVS). PI3K/AKT3 then activates the IRF3 and IRF7 by phosphorylating IRF3 at Ser385 and IRF7 at Ser437/438 mediating type I IFN production. Together, we reveal a critical role for PARP9 as a non-canonical RNA sensor that depends on the PI3K/AKT3 pathway to produce type I IFN. These findings may have important clinical implications in controlling viral infections and viral-induced diseases by targeting PARP9.

scholarly journals HIV-1 Vpr Degrades TET2 to Suppress IRF7 and Interferon Expression in Plasmacytoid Dendritic Cells

2019 ◽  
Author(s):  
Qi Wang ◽  
Li-Chung Tsao ◽  
Lei Lv ◽  
Yanping Xu ◽  
Liang Cheng ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Viral Infections ◽  
Constitutive Expression ◽  
Plasmacytoid Dendritic Cells ◽  
Type I Interferons ◽  
Type I ◽  
Restriction Factors ◽  
Host Restriction ◽  
Host Restriction Factors ◽  
Hiv 1

AbstractPlasmacytoid dendritic cells (pDCs) are the major source of type I interferons (IFN-I) in rapid response to viral infections, with constitutive expression of interferon regulatory factor 7 (IRF7). HIV-1 expresses several accessory proteins to counteract specific IFN-induced host restriction factors. As one abundant virion-associated protein, HIV-1 Vpr remains enigmatic in enhancing HIV-1 infection via unclear mechanisms. Here we report that Vpr impaired IFN-I induction in pDCs to enhance HIV-1 replication in CD4+ T cells. Blockade of IFN-I signaling abrogated the effect of Vpr on HIV-1 replication. Virion-associated Vpr suppressed IFN-I induction in pDC by TLR7 agonists. Modulation of IFN-I induction by Vpr was genetically dependent on its activity of TET2 degradation. We further demonstrate that Vpr-mediated TET2 degradation reduced expression of IRF7 in pDCs. Finally, degradation of TET2 in pDCs by Vpr reduced the demethylation level of the IRF7 promoter via CXXC5-dependent recruitment. We conclude that HIV-1 Vpr functions to promote HIV-1 replication by suppressing TET2-dependent IRF7 expression and IFN-I induction in pDCs. The Vpr-TET2-IRF7 axis provides a novel therapeutic target to control HIV-1 infection.

scholarly journals Toll-like Receptor 9–mediated Recognition of Herpes Simplex Virus-2 by Plasmacytoid Dendritic Cells

2003 ◽  
Vol 198 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Jennifer Lund ◽  
Ayuko Sato ◽  
Shizuo Akira ◽  
Ruslan Medzhitov ◽  
Akiko Iwasaki
Keyword(s):  
Dendritic Cells ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Plasmacytoid Dendritic Cells ◽  
Endocytic Pathway ◽  
Type I ◽  
Dependent Manner ◽  
Toll Like Receptor ◽  
Simplex Virus ◽  
Herpes Simplex Virus 2

Plasmacytoid dendritic cells (pDCs) have been identified as a potent secretor of the type I interferons (IFNs) in response to CpG as well as several viruses. In this study, we examined the molecular mechanism of virus recognition by pDCs. First, we demonstrated that the CD11c+Gr-1intB220+ pDCs from mouse bone marrow secreted high levels of IFN-α in response to either live or UV-inactivated Herpes simplex virus-2 (HSV-2). Next, we identified that IFN-α secretion by pDCs required the expression of the adaptor molecule MyD88, suggesting the involvement of a Toll-like receptor (TLR) in HSV-2 recognition. To test whether a TLR mediates HSV-2–induced IFN-α secretion from pDCs, various knockout mice were examined. These experiments revealed a clear requirement for TLR9 in this process. Further, we demonstrated that purified HSV-2 DNA can trigger IFN-α secretion from pDCs and that inhibitory CpG oligonucleotide treatment diminished HSV-induced IFN-α secretion by pDCs in a dose-dependent manner. The recognition of HSV-2 by TLR9 was mediated through an endocytic pathway that was inhibited by chloroquine or bafilomycin A1. The strict requirement for TLR9 in IFN-α secretion was further confirmed by the inoculation of HSV-2 in vivo. Therefore, these results demonstrate a novel mechanism whereby the genomic DNA of a virus can engage TLR9 and result in the secretion of IFN-α by pDCs.

scholarly journals Human plasmacytoid dendritic cells are equipped with antigen-presenting and tumoricidal capacities

Blood ◽  
2012 ◽  
Vol 120 (19) ◽  
pp. 3936-3944 ◽  
Author(s):  
Jurjen Tel ◽  
Evelien L. Smits ◽  
Sébastien Anguille ◽  
Rubin N. Joshi ◽  
Carl G. Figdor ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Viral Infections ◽  
Cell Subset ◽  
Plasmacytoid Dendritic Cells ◽  
Type I Interferons ◽  
Human Interferon ◽  
Target Cells ◽  
Type I ◽  
Dendritic Cell Subset ◽  
Antigen Presenting

Abstract Human plasmacytoid dendritic cells (pDCs) represent a highly specialized naturally occurring dendritic-cell subset and are the main producers of type I interferons (IFNs) in response to viral infections. We show that human pDCs activated by the preventive vaccine FSME specifically up-regulate CD56 on their surface, a marker that was thought to be specific for NK cells and associated with cytolytic effector functions. We observed that FSME-activated pDCs specifically lysed NK target cells and expressed cytotoxic molecules, such as tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and granzyme B. Elevated levels of these molecules coincided with the expression of CD56, indicative for skewing human pDCs toward an interferon-producing killer DC subset. Detailed phenotypical and functional analysis revealed that pDCs attained a mature phenotype, secreted proinflammatory cytokines, and had the capacity to present antigens and stimulate T cells. Here, we report on the generation of CD56+ human interferon producing killer pDCs with the capacity to present antigens. These findings aid in deciphering the role for pDCs in antitumor immunity and present a promising prospect of developing antitumor therapy using pDCs.

scholarly journals A type I IFN–Flt3 ligand axis augments plasmacytoid dendritic cell development from common lymphoid progenitors

2013 ◽  
Vol 210 (12) ◽  
pp. 2515-2522 ◽  
Author(s):  
Yi-Ling Chen ◽  
Ting-Ting Chen ◽  
Li-Mei Pai ◽  
Joanna Wesoly ◽  
Hans A.R. Bluyssen ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Dendritic Cell ◽  
Type I Interferon ◽  
Plasmacytoid Dendritic Cell ◽  
Critical Role ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
Type I Ifn ◽  
Flt3 Ligand ◽  
Lymphoid Progenitors

During infections and inflammation, plasmacytoid dendritic cells (pDCs) are the most potent type I interferon (IFN-I)–producing cells. However, the developmental origin of pDCs and the signals dictating pDC generation remain incompletely understood. Here, we report a synergistic role for IFN-I and Flt3 ligand (FL) in pDC development from common lymphoid progenitors (CLPs). Both conventional DCs (cDCs) and pDCs were generated from CLPs in response to FL, whereas pDC generation required higher concentrations of FL and concurrent IFN-I signaling. An absence of IFN-I receptor, impairment of IFN-I signaling, or neutralization of IFN-I significantly impeded pDC development from CLPs. Furthermore, FL induced IFN-I expression in CLPs, which in turn induced Flt3 up-regulation that facilitated survival and proliferation of CLPs, as well as their differentiation into pDCs. Collectively, these results define a critical role for the FL/IFN-I/Flt3 axis in pDC differentiation from CLPs.

scholarly journals Role of CD123 (+) Plasmacytoid Dendritic Cells in Etiologically Different Variants of Erythema Multiforme: A Monocentric Retrospective Study

2021 ◽  
Vol 8 (2) ◽  
pp. 89-96
Author(s):  
Hatice B. Zengin ◽  
Tatsiana Pukhalskaya ◽  
Bruce R. Smoller
Keyword(s):  
Dendritic Cells ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Erythema Multiforme ◽  
Inflammatory Infiltrate ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
A Cell ◽  
Skin Conditions ◽  
Simplex Virus

Plasmacytoid dendritic cells (pDCs) constitute a subset of dendritic cells known to be the “professional” interferon type I (IFN-I) producers. pDCs play an important role in antiviral immunity, as well as linking innate and adaptive immunity. Under normal conditions pDCs are not present in skin. They are shown to be a part of the inflammatory infiltrate in different skin conditions including erythema multiforme (EM). This condition is considered to be a cell-mediated immune reaction to a wide variety of agents, most commonly herpes simplex virus. Nevertheless, the pathophysiology of EM still remains unclear. In this study, we grouped 32 biopsies from 30 patients diagnosed with EM, based on their etiology and analyzed the density and distribution of CD123 positive pDCs. In all cases we observed a greatly increased number of pDCs in the dermal inflammatory infiltrate. Virally-induced EM (by herpes simplex virus (HSV) and other viruses) was more likely to have a significantly higher number of pDCs compared to non-virally associated EM. Hence, we think that pDCs play a key role in the pathogenesis of EM independent of etiology and may play an increased role in virally-associated cases. Further studies on pDCs would clarify their importance in EM and improve our understanding of the pathophysiology of this disease.

scholarly journals The Pseudorabies Virus Glycoprotein gE/gI Complex Suppresses Type I Interferon Production by Plasmacytoid Dendritic Cells

2017 ◽  
Vol 91 (7) ◽  
Author(s):  
Jochen A. S. Lamote ◽  
Manon Kestens ◽  
Cliff Van Waesberghe ◽  
Jonas Delva ◽  
Steffi De Pelsmaeker ◽  
...  
Keyword(s):  
Immune Response ◽  
Dendritic Cells ◽  
Vaccine Strain ◽  
Rational Design ◽  
Pseudorabies Virus ◽  
Type I Interferon ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
Wild Type ◽  
The Impact

ABSTRACT Plasmacytoid dendritic cells (pDC) play a central role in the antiviral immune response, both in the innate response and in shaping the adaptive response, mainly because of their ability to produce massive amounts of type I interferon (TI-IFN). Here, we report that cells infected with the live attenuated Bartha vaccine strain of porcine alphaherpesvirus pseudorabies virus (PRV) trigger a dramatically increased TI-IFN response by porcine primary pDC compared to cells infected with wild-type PRV strains (Becker and Kaplan). Since Bartha is one of the relatively few examples of a highly successful alphaherpesvirus vaccine, identification of factors that may contribute to its efficacy may provide insights for the rational design of other alphaherpesvirus vaccines. The Bartha vaccine genome displays several mutations compared to the genome of wild-type PRV strains, including a large deletion in the unique short (US) region, encompassing the glycoprotein E (gE), gI, US9, and US2 genes. Using recombinant PRV Becker strains harboring the entire Bartha US deletion or single mutations in the four affected US genes, we demonstrate that the absence of the viral gE/gI complex contributes to the observed increased IFN-α response. Furthermore, we show that the absence of gE leads to an enhanced extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation in pDC, which correlates with a higher TI-IFN production by pDC. In conclusion, the PRV Bartha vaccine strain triggers strongly increased TI-IFN production by porcine pDC. Our data further indicate that the gE/gI glycoprotein complex suppresses TI-IFN production by pDC, which represents the first alphaherpesvirus factor that suppresses pDC activity. IMPORTANCE Several alphaherpesviruses, including herpes simpex virus, still lack effective vaccines. However, the highly successful Bartha vaccine has contributed substantially to eradication of the porcine alphaherpesvirus pseudorabies virus (PRV) in several countries. The impact of Bartha on the immune response is still poorly understood. Type I interferon (TI-IFN)-producing plasmacytoid dendritic cells (pDC) may play an important role in vaccine development. Here, we show that Bartha elicits a dramatically increased type I interferon (TI-IFN) response in primary porcine pDC compared to wild-type strains. In addition, we found that the gE/gI complex, which is absent in Bartha, inhibits the pDC TI-IFN response. This is the first description of an immune cell type that is differentially affected by Bartha versus wild-type PRV and is the first report describing an alphaherpesvirus protein that inhibits the TI-IFN response by pDC. These data may therefore contribute to the rational design of other alphaherpesvirus vaccines.

scholarly journals Bclaf1 critically regulates the type I interferon response and is degraded by alphaherpesvirus US3

2018 ◽  
Author(s):  
Chao Qin ◽  
Rui Zhang ◽  
Yue Lang ◽  
Anwen Shao ◽  
Aotian Xu ◽  
...  
Keyword(s):  
Gene Transcription ◽  
Pseudorabies Virus ◽  
Viral Infections ◽  
Type I Interferon ◽  
Interferon Response ◽  
Interferon Α ◽  
Type I ◽  
Viral Inhibition ◽  
Simplex Virus ◽  
Hsv 1

AbstractType I interferon response plays a prominent role against viral infection, which is frequently disrupted by viruses. Here, we report Bcl-2 associated transcription factor 1 (Bclaf1) is degraded during the alphaherpesvirus Pseudorabies virus (PRV) and Herpes simplex virus type 1 (HSV-1) infections through the viral protein US3. We further reveal that Bclaf1 functions critically in type I interferon signaling. Knockdown or knockout of Bclaf1 in cells significantly impairs interferon-α (IFNα)-mediated gene transcription and viral inhibition against US3 deficient PRV and HSV-1. Mechanistically, Bclaf1 maintains a mechanism allowing STAT1 and STAT2 to be efficiently phosphorylated in response to IFNα, and more importantly, facilitates IFN-stimulated gene factor 3 (ISGF3) binding with IFN-stimulated response elements (ISRE) for efficient gene transcription by directly interacting with ISRE and STAT2. Our studies establish the importance of Bclaf1 in IFNα-induced antiviral immunity and in the control of viral infections.

scholarly journals Type I Interferon Production of Plasmacytoid Dendritic Cells under Control

2021 ◽  
Vol 22 (8) ◽  
pp. 4190
Author(s):  
Dóra Bencze ◽  
Tünde Fekete ◽  
Kitti Pázmándi
Keyword(s):  
Dendritic Cells ◽  
Viral Infections ◽  
Plasmacytoid Dendritic Cells ◽  
Type I Interferons ◽  
Type I ◽  
Type I Ifn ◽  
Tumor Resistance ◽  
Endogenous Factors ◽  
Associated Diseases ◽  
Type I Ifns

One of the most powerful and multifaceted cytokines produced by immune cells are type I interferons (IFNs), the basal secretion of which contributes to the maintenance of immune homeostasis, while their activation-induced production is essential to effective immune responses. Although, each cell is capable of producing type I IFNs, plasmacytoid dendritic cells (pDCs) possess a unique ability to rapidly produce large amounts of them. Importantly, type I IFNs have a prominent role in the pathomechanism of various pDC-associated diseases. Deficiency in type I IFN production increases the risk of more severe viral infections and the development of certain allergic reactions, and supports tumor resistance; nevertheless, its overproduction promotes autoimmune reactions. Therefore, the tight regulation of type I IFN responses of pDCs is essential to maintain an adequate level of immune response without causing adverse effects. Here, our goal was to summarize those endogenous factors that can influence the type I IFN responses of pDCs, and thus might serve as possible therapeutic targets in pDC-associated diseases. Furthermore, we briefly discuss the current therapeutic approaches targeting the pDC-type I IFN axis in viral infections, cancer, autoimmunity, and allergy, together with their limitations defined by the Janus-faced nature of pDC-derived type I IFNs.

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