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The virion host shut-off (vhs) protein blocks a TLR-independent pathway of herpes simplex virus type 1 recognition in human and mouse dendritic cells.

Cotter CR, Nguyen ML, Yount JS, López CB, Blaho JA, Moran TM - PLoS ONE (2010)

Bottom Line: These data prompted us to postulate that infection of cDCs by HSV triggers a TLR independent pathway for cDC activation that is susceptible to blockage by the vhs protein.This block to SeV- and NDV-induced activation of cDC resulted in elevated SeV and NDV viral gene expression indicating that infection with HSV-1 enhances the cell's susceptibility to other pathogens through the action of vhs.Our results demonstrate for the first time that a viral protein contained in the tegument of HSV-1 can block the induction of DC activation by TLR-independent pathways of viral recognition.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology Institute, Mount Sinai School of Medicine, New York, New York, USA.

ABSTRACT
Molecular pathways underlying the activation of dendritic cells (DCs) in response to Herpes Simplex Virus type 1 (HSV-1) are poorly understood. Removal of the HSV virion host shut-off (vhs) protein relieves a block to DC activation observed during wild-type infection. In this study, we utilized a potent DC stimulatory HSV-1 recombinant virus lacking vhs as a tool to investigate the mechanisms involved in the activation of DCs by HSV-1. We report that the release of pro-inflammatory cytokines by conventional DC (cDC) during HSV-1 infection is triggered by both virus replication-dependent and replication-independent pathways. Interestingly, while vhs is capable of inhibiting the release of cytokines during infection of human and mouse cDCs, the secretion of cytokines by plasmacytoid DC (pDC) is not affected by vhs. These data prompted us to postulate that infection of cDCs by HSV triggers a TLR independent pathway for cDC activation that is susceptible to blockage by the vhs protein. Using cDCs isolated from mice deficient in both the TLR adaptor protein MyD88 and TLR3, we show that HSV-1 and the vhs-deleted virus can activate cDCs independently of TLR signaling. In addition, virion-associated vhs fails to block cDC activation in response to treatment with TLR agonists, but it efficiently blocked cDC activation triggered by the paramyxoviruses Sendai Virus (SeV) and Newcastle Disease Virus (NDV). This block to SeV- and NDV-induced activation of cDC resulted in elevated SeV and NDV viral gene expression indicating that infection with HSV-1 enhances the cell's susceptibility to other pathogens through the action of vhs. Our results demonstrate for the first time that a viral protein contained in the tegument of HSV-1 can block the induction of DC activation by TLR-independent pathways of viral recognition.

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HSV-1 modulates the activation of murine-derived DCs similar to human-derived DCs.(a.) mu-cDCs were infected with both live and UV inactivated virus stocks at an MOI of 5. At 12 hpi, cells were harvested, and the levels of IL-6 and IL-12p40 were measured in the supernatants (ELISA). qRT-PCR was used to measure the mRNA levels of IP-10 within infected cells. Data is represented as relative expression relative to levels of housekeeping genes. Error bars denote the difference between duplicate (ELISA) and triplicate (PCR) assays. (b.) mu-pDCs were infected with KOS and vhs- viruses at an MOI of 5; released IL-6 and TNF-α were measured by ELISA assay at 6 hpi. (c.) mu-cDCs were infected with KOS and vhs- viruses; cell surface expression of mu-CD80 was measured by Flow Cytometry at 24 hpi.
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pone-0008684-g004: HSV-1 modulates the activation of murine-derived DCs similar to human-derived DCs.(a.) mu-cDCs were infected with both live and UV inactivated virus stocks at an MOI of 5. At 12 hpi, cells were harvested, and the levels of IL-6 and IL-12p40 were measured in the supernatants (ELISA). qRT-PCR was used to measure the mRNA levels of IP-10 within infected cells. Data is represented as relative expression relative to levels of housekeeping genes. Error bars denote the difference between duplicate (ELISA) and triplicate (PCR) assays. (b.) mu-pDCs were infected with KOS and vhs- viruses at an MOI of 5; released IL-6 and TNF-α were measured by ELISA assay at 6 hpi. (c.) mu-cDCs were infected with KOS and vhs- viruses; cell surface expression of mu-CD80 was measured by Flow Cytometry at 24 hpi.

Mentions: Due to the inherent difficulties in genetically manipulating human systems in addressing mechanistic questions, we shifted our study to a mouse bone marrow-derived DC system. As shown in Figure 4, HSV-1 modulated the secretion of pro-inflammatory cytokines and co-stimulatory molecules in murine DCs in a manner similar to that of human DCs (Figure 2a, 2b and Figure 3a). We also detected the expression of HSV-1 lytic transcripts during infection mu-cDCs (data not shown).


The virion host shut-off (vhs) protein blocks a TLR-independent pathway of herpes simplex virus type 1 recognition in human and mouse dendritic cells.

Cotter CR, Nguyen ML, Yount JS, López CB, Blaho JA, Moran TM - PLoS ONE (2010)

HSV-1 modulates the activation of murine-derived DCs similar to human-derived DCs.(a.) mu-cDCs were infected with both live and UV inactivated virus stocks at an MOI of 5. At 12 hpi, cells were harvested, and the levels of IL-6 and IL-12p40 were measured in the supernatants (ELISA). qRT-PCR was used to measure the mRNA levels of IP-10 within infected cells. Data is represented as relative expression relative to levels of housekeeping genes. Error bars denote the difference between duplicate (ELISA) and triplicate (PCR) assays. (b.) mu-pDCs were infected with KOS and vhs- viruses at an MOI of 5; released IL-6 and TNF-α were measured by ELISA assay at 6 hpi. (c.) mu-cDCs were infected with KOS and vhs- viruses; cell surface expression of mu-CD80 was measured by Flow Cytometry at 24 hpi.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2823768&req=5

pone-0008684-g004: HSV-1 modulates the activation of murine-derived DCs similar to human-derived DCs.(a.) mu-cDCs were infected with both live and UV inactivated virus stocks at an MOI of 5. At 12 hpi, cells were harvested, and the levels of IL-6 and IL-12p40 were measured in the supernatants (ELISA). qRT-PCR was used to measure the mRNA levels of IP-10 within infected cells. Data is represented as relative expression relative to levels of housekeeping genes. Error bars denote the difference between duplicate (ELISA) and triplicate (PCR) assays. (b.) mu-pDCs were infected with KOS and vhs- viruses at an MOI of 5; released IL-6 and TNF-α were measured by ELISA assay at 6 hpi. (c.) mu-cDCs were infected with KOS and vhs- viruses; cell surface expression of mu-CD80 was measured by Flow Cytometry at 24 hpi.
Mentions: Due to the inherent difficulties in genetically manipulating human systems in addressing mechanistic questions, we shifted our study to a mouse bone marrow-derived DC system. As shown in Figure 4, HSV-1 modulated the secretion of pro-inflammatory cytokines and co-stimulatory molecules in murine DCs in a manner similar to that of human DCs (Figure 2a, 2b and Figure 3a). We also detected the expression of HSV-1 lytic transcripts during infection mu-cDCs (data not shown).

Bottom Line: These data prompted us to postulate that infection of cDCs by HSV triggers a TLR independent pathway for cDC activation that is susceptible to blockage by the vhs protein.This block to SeV- and NDV-induced activation of cDC resulted in elevated SeV and NDV viral gene expression indicating that infection with HSV-1 enhances the cell's susceptibility to other pathogens through the action of vhs.Our results demonstrate for the first time that a viral protein contained in the tegument of HSV-1 can block the induction of DC activation by TLR-independent pathways of viral recognition.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology Institute, Mount Sinai School of Medicine, New York, New York, USA.

ABSTRACT
Molecular pathways underlying the activation of dendritic cells (DCs) in response to Herpes Simplex Virus type 1 (HSV-1) are poorly understood. Removal of the HSV virion host shut-off (vhs) protein relieves a block to DC activation observed during wild-type infection. In this study, we utilized a potent DC stimulatory HSV-1 recombinant virus lacking vhs as a tool to investigate the mechanisms involved in the activation of DCs by HSV-1. We report that the release of pro-inflammatory cytokines by conventional DC (cDC) during HSV-1 infection is triggered by both virus replication-dependent and replication-independent pathways. Interestingly, while vhs is capable of inhibiting the release of cytokines during infection of human and mouse cDCs, the secretion of cytokines by plasmacytoid DC (pDC) is not affected by vhs. These data prompted us to postulate that infection of cDCs by HSV triggers a TLR independent pathway for cDC activation that is susceptible to blockage by the vhs protein. Using cDCs isolated from mice deficient in both the TLR adaptor protein MyD88 and TLR3, we show that HSV-1 and the vhs-deleted virus can activate cDCs independently of TLR signaling. In addition, virion-associated vhs fails to block cDC activation in response to treatment with TLR agonists, but it efficiently blocked cDC activation triggered by the paramyxoviruses Sendai Virus (SeV) and Newcastle Disease Virus (NDV). This block to SeV- and NDV-induced activation of cDC resulted in elevated SeV and NDV viral gene expression indicating that infection with HSV-1 enhances the cell's susceptibility to other pathogens through the action of vhs. Our results demonstrate for the first time that a viral protein contained in the tegument of HSV-1 can block the induction of DC activation by TLR-independent pathways of viral recognition.

Show MeSH
Related in: MedlinePlus