scholarly journals Checks and balances between human cytomegalovirus replication and indoleamine-2,3-dioxygenase

2014 ◽  
Vol 95 (3) ◽  
pp. 659-670 ◽  
Author(s):  
Albert Zimmermann ◽  
Sebastian Hauka ◽  
Marco Maywald ◽  
Vu Thuy Khanh Le ◽  
Silvia K. Schmidt ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Human Cytomegalovirus ◽  
Cell Types ◽  
Interferon Γ ◽  
Counter Measures ◽  
Indoleamine 2,3 Dioxygenase ◽  
Infected Cells ◽  
Hcmv Replication ◽  
Ifn Γ ◽  
The Impact

Despite a rigorous blockade of interferon-γ (IFN-γ) signalling in infected fibroblasts as a mechanism of immune evasion by human cytomegalovirus (HCMV), IFN-γ induced indoleamine-2,3-dioxygenase (IDO) has been proposed to represent the major antiviral restriction factor limiting HCMV replication in epithelial cells. Here we show that HCMV efficiently blocks transcription of IFN-γ-induced IDO mRNA both in infected fibroblasts and epithelial cells even in the presence of a preexisting IFN-induced antiviral state. This interference results in severe suppression of IDO bioactivity in HCMV-infected cells and restoration of vigorous HCMV replication. Depletion of IDO expression nonetheless substantially alleviated the antiviral impact of IFN-γ treatment in both cell types. These findings highlight the effectiveness of this IFN-γ induced effector gene in restricting HCMV productivity, but also the impact of viral counter-measures.

Human intestinal intraepithelial lymphocytes and epithelial cells coinduce interleukin-8 production through the CD2-CD58 interaction

2009 ◽  
Vol 296 (3) ◽  
pp. G671-G677 ◽  
Author(s):  
Ellen C. Ebert ◽  
Asit Panja ◽  
Rajalakshmi Praveen
Keyword(s):  
Epithelial Cells ◽  
Cell Types ◽  
Interferon Γ ◽  
Intraepithelial Lymphocytes ◽  
Cell Contact ◽  
Tnf Α ◽  
Active Transcription ◽  
Ifn Γ ◽  
Factor Α ◽  
Ht 29

Human intestinal CD3+TCRαβ+CD8+ intraepithelial lymphocytes (IELs) are intimately associated with epithelial cells (ECs) through binding of CD103 to E-cadherin. How these two cell types functionally interact is largely unknown. IEL-EC cross talk was determined using HT-29 cells as the model EC and IL-8 as the readout. IL-8 was derived from both cell types and synergistically increased when the cells were combined. This synergistic effect required active transcription by both IELs and HT-29 cells. Cell contact was required as shown by the loss of the synergistic increase in IL-8 when the two cell types were separated by Transwells. Specifically, IL-8 release required the binding of CD2 on the IELs to CD58 on the HT-29 cells. The association of the CD3/TCR complex with major histocompatibility antigen class I antigens was not involved. Antibody neutralization of tumor necrosis factor-α (TNF-α), but not interferon-γ (IFN-γ), resulted in increased IL-8 production by the coculture. Although both TNF-α and IFN-γ increased IL-8 synthesis and CD58 expression by the HT-29 cells, only IFN-γ reduced IL-8 production by IELs. IL-8 production by either cell type involved phosphorylation of p38 and JNK. In summary, the synergistic synthesis of IL-8 occurs when IELs are stimulated through the CD2 pathway by CD58 on HT-29 cells, resulting in TNF-α release that, in turn, augments IL-8 synthesis and CD58 expression by the HT-29 cells.

scholarly journals Hypoxia-Inducible Factor 1α (HIF1α) Suppresses Virus Replication in Human Cytomegalovirus Infection by Limiting Kynurenine Synthesis

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Lisa M. Wise ◽  
Yuecheng Xi ◽  
John G. Purdy
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Virus Replication ◽  
Human Cytomegalovirus ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Inducible Factor 1Α ◽  
Indoleamine 2,3 Dioxygenase ◽  
Aryl Hydrocarbon ◽  
Infected Cells ◽  
Hcmv Replication ◽  
Rate Limiting

ABSTRACT Human cytomegalovirus (HCMV) replication depends on the activities of several host regulators of metabolism. Hypoxia-inducible factor 1α (HIF1α) was previously proposed to support virus replication through its metabolic regulatory function. HIF1α protein levels rise in response to HCMV infection in nonhypoxic conditions, but its effect on HCMV replication was not investigated. We addressed the role of HIF1α in HCMV replication by generating primary human cells with HIF1α knocked out using CRISPR/Cas9. When HIF1α was absent, we found that HCMV replication was enhanced, showing that HIF1α suppresses viral replication. We used untargeted metabolomics to determine if HIF1α regulates metabolite concentrations in HCMV-infected cells. We discovered that in HCMV-infected cells, HIF1α suppresses intracellular and extracellular concentrations of kynurenine. HIF1α also suppressed the expression of indoleamine 2,3-dioxygenase 1 (IDO1), the rate-limiting enzyme in kynurenine synthesis. In addition to its role in tryptophan metabolism, kynurenine acts as a signaling messenger by activating aryl hydrocarbon receptor (AhR). Inhibiting AhR reduces HCMV replication, while activating AhR with an exogenous ligand increases virus replication. Moreover, we found that feeding kynurenine to cells promotes HCMV replication. Overall, our findings indicate that HIF1α reduces HCMV replication by regulating metabolism and metabolite signaling. IMPORTANCE Viruses, including human cytomegalovirus (HCMV), reprogram cellular metabolism using host metabolic regulators to support virus replication. Alternatively, in response to infection, the host can use metabolism to limit virus replication. Here, our findings show that the host uses hypoxia-inducible factor 1α (HIF1α) as a metabolic regulator to reduce HCMV replication. Further, we found that HIF1α suppresses kynurenine synthesis, a metabolite that can promote HCMV replication by signaling through the aryl hydrocarbon receptor (AhR). In infected cells, the rate-limiting enzyme in kynurenine synthesis, indoleamine 2,3-dioxygenase 1 (IDO1), is suppressed by a HIF1α-dependent mechanism. Our findings describe a functional connection between HIF1α, IDO1, and AhR that allows HIF1α to limit HCMV replication through metabolic regulation, advancing our understanding of virus-host interactions.

Human cytomegalovirus protein pp65 mediates accumulation of HLA-DR in lysosomes and destruction of the HLA-DR α-chain

Blood ◽  
2003 ◽  
Vol 101 (12) ◽  
pp. 4870-4877 ◽  
Author(s):  
Jenny Odeberg ◽  
Bodo Plachter ◽  
Lars Brandén ◽  
Cecilia Söderberg-Nauclér
Keyword(s):  
Human Cytomegalovirus ◽  
Interferon Γ ◽  
Immune Recognition ◽  
Multiple Strategies ◽  
Hla Dr ◽  
Infected Cells ◽  
Ifn Γ ◽  
Α Chain ◽  
Β Chain ◽  
Hla Class Ii Molecules

AbstractHuman cytomegalovirus (HCMV) has developed multiple strategies to escape immune recognition. Here, we demonstrate that HCMV down-regulates HLA-DR expression in infected interferon γ (IFN-γ)–stimulated fibroblasts at 1 day after infection. Decreased HLA-DR expression was not observed on cells infected with an HCMV strain lacking the pp65 gene (RVAD65), but was observed on cells transfected with the pp65 gene. HLA-DR expression accumulated in vacuoles near the nucleus in HCMV-infected, but not in uninfected or RVAD65-infected cells. In addition, the HLA-DR α-chain, but not the β-chain or HLA-DM, was degraded in HCMV-infected but not in RVAD65-infected cells. Thus, the HCMV protein pp65 mediates decreased expression of HLA-DR, by mediating an accumulation of HLA class II molecules in lysosomes that results in degradation of the HLA-DR α-chain.

scholarly journals Hypoxia-inducible factor 1α (HIF1α) Suppresses Virus Replication in Human Cytomegalovirus Infection by Limiting Kynurenine Synthesis

2021 ◽  
Author(s):  
Lisa M. Wise ◽  
Yuecheng Xi ◽  
John G. Purdy
Keyword(s):  
Aryl Hydrocarbon Receptor ◽  
Virus Replication ◽  
Human Cytomegalovirus ◽  
Hypoxia Inducible Factor ◽  
Hypoxia Inducible Factor 1Α ◽  
Indoleamine 2,3 Dioxygenase ◽  
Aryl Hydrocarbon ◽  
Infected Cells ◽  
Hcmv Replication ◽  
Rate Limiting

AbstractHuman cytomegalovirus (HCMV) replication depends on the activities of several host regulators of metabolism. Hypoxia-inducible factor 1α (HIF1α) was previously proposed to support virus replication through its metabolic regulatory function. HIF1α protein levels rise in response to HCMV infection in non-hypoxic conditions, but its effect on HCMV replication was not investigated. We addressed the role of HIF1α in HCMV replication by generating primary human cells with HIF1α knocked out using CRISPR/Cas9. When HIF1α was absent, we found that HCMV replication was enhanced, showing that HIF1α suppresses viral replication. We used untargeted metabolomics to determine if HIF1α regulates metabolite concentrations in HCMV infected cells. We discovered that in HCMV-infected cells, HIF1α suppresses intracellular and extracellular concentrations of kynurenine. HIF1α also suppressed the expression of the indoleamine 2,3-dioxygenase 1 (IDO1) rate-limiting enzyme in kynurenine synthesis. In addition to its role in tryptophan metabolism, kynurenine acts as a signaling messenger by activating aryl hydrocarbon receptor (AhR). Inhibiting AhR reduces HCMV replication while activating AhR with an exogenous ligand increases HCMV replication. Moreover, we found that feeding kynurenine to cells promotes HCMV replication. Overall, our findings indicate that HIF1α reduces HCMV replication by regulating metabolism and metabolite signaling.ImportanceViruses, like human cytomegalovirus (HCMV), reprogram cellular metabolism using host metabolic regulators to support virus replication. Alternatively, in response to infection, the host can use metabolism to limit virus replication. Here, our findings show that the host uses hypoxia-inducible factor 1α (HIF1α) as a metabolic regulator to reduce HCMV replication. Further, we found that HIF1α suppresses kynurenine synthesis, a metabolite that can promote HCMV replication by signaling through the aryl hydrocarbon receptor (AhR). In infected cells, the rate-limiting enzyme in kynurenine synthesis, indoleamine 2,3-dioxygenase 1 (IDO1), is suppressed by a HIF1α-dependent mechanism. Our findings describe a functional connection between HIF1α, IDO1, and AhR that allows HIF1α to limit HCMV replication through metabolic regulation, advancing our understanding of virus-host interactions.

scholarly journals Human Cytomegalovirus Persistently Infects Aortic Endothelial Cells

1998 ◽  
Vol 72 (7) ◽  
pp. 5661-5668 ◽  
Author(s):  
Kenneth N. Fish ◽  
Cecilia Soderberg-Naucler ◽  
Lisa K. Mills ◽  
Stephan Stenglein ◽  
Jay A. Nelson
Keyword(s):  
Endothelial Cells ◽  
Human Cytomegalovirus ◽  
Antigen Expression ◽  
Cell Types ◽  
Aortic Endothelial Cells ◽  
Phenotypic Differences ◽  
Extracellular Virus ◽  
Viral Particles ◽  
Infected Cells ◽  
Hcmv Replication

ABSTRACT Endothelial cells (EC) have been implicated as constituting an important cell type in the pathogenesis of human cytomegalovirus (HCMV). Microvascular and macrovascular EC exhibit different biochemical and functional properties depending on the organ of origin. Phenotypic differences between microvascular and macrovascular EC may alter the ability of these cells to support HCMV replication. In this study, we compared the replication of HCMV in primary macrovascular aortic EC (AEC) with that in brain microvascular EC (BMVEC). An examination of IE72, pp65, and gB viral antigen expression in BMVEC and AEC by immunoflourescence revealed similar frequencies of infected cells. Intracellular production of virus was 3 log units greater in BMVEC than in AEC, while equal quantities of extracellular virus were produced in both cell types. HCMV infection of BMVEC resulted in rapid cellular lysis, while the virus was nonlytic and continuously released from HCMV-infected AEC for the life span of the culture. An examination of infected cells by electron microscopy revealed the formation of abundant nucleocapsids in both AEC and BMVEC. However, significant amounts of mature viral particles were only detected in the cytoplasm of BMVEC. These observations indicate that levels of HCMV replication in EC obtained from different organs are distinct and suggest that persistently infected AEC may serve as a reservoir of virus.

scholarly journals Differential Regulation of Cathepsin S and Cathepsin L in Interferon γ–treated Macrophages

2003 ◽  
Vol 197 (2) ◽  
pp. 169-179 ◽  
Author(s):  
Courtney Beers ◽  
Karen Honey ◽  
Susan Fink ◽  
Katherine Forbush ◽  
Alexander Rudensky
Keyword(s):  
Cathepsin L ◽  
Specific Inhibitor ◽  
Cell Types ◽  
Interferon Γ ◽  
Cathepsin S ◽  
Antigen Presenting Cell ◽  
Relative Contribution ◽  
Helper Cell Type ◽  
Ifn Γ ◽  
Antigen Presenting

Cathepsin S (catS) and cathepsin L (catL) mediate late stages of invariant chain (Ii) degradation in discrete antigen-presenting cell types. Macrophages (Mϕs) are unique in that they express both proteases and here we sought to determine the relative contribution of each enzyme. We observe that catL plays no significant role in Ii cleavage in interferon (IFN)-γ–stimulated Mϕs. In addition, our studies show that the level of catL activity is significantly decreased in Mϕs cultured in the presence of IFN-γ whereas catS activity increases. The decrease in catL activity upon cytokine treatment occurs despite the persistence of high levels of mature catL protein, suggesting that a specific inhibitor of the enzyme is up-regulated in IFN-γ–stimulated peritoneal Mϕs. Similar inhibition of activity is observed in dendritic cells engineered to overexpress catL. Such enzymatic inhibition in Mϕs exhibits only partial dependence upon Ii and therefore, other mechanisms of catL inhibition are regulated by IFN-γ. Thus, during a T helper cell type 1 immune response catL inhibition in Mϕs results in preferential usage of catS, such that major histocompatibility complex class II presentation by all bone marrow–derived antigen-presenting cell is regulated by catS.

Early human cytomegalovirus replication after transplantation is associated with a decreased relapse risk: evidence for a putative virus-versus-leukemia effect in acute myeloid leukemia patients

Blood ◽  
2011 ◽  
Vol 118 (5) ◽  
pp. 1402-1412 ◽  
Author(s):  
Ahmet H. Elmaagacli ◽  
Nina K. Steckel ◽  
Michael Koldehoff ◽  
Yael Hegerfeldt ◽  
Rudolf Trenschel ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Human Cytomegalovirus ◽  
Myeloid Leukemia ◽  
Homogeneous Population ◽  
Relapse Risk ◽  
Pp65 Antigenemia ◽  
Hcmv Replication ◽  
The Impact ◽  
Early Human ◽  
Acute Myeloid

Abstract The impact of early human cytomegalovirus (HCMV) replication on leukemic recurrence was evaluated in 266 consecutive adult (median age, 47 years; range, 18-73 years) acute myeloid leukemia patients, who underwent allogeneic stem cell transplantation (alloSCT) from 10 of 10 high-resolution human leukocyte Ag-identical unrelated (n = 148) or sibling (n = 118) donors. A total of 63% of patients (n = 167) were at risk for HCMV reactivation by patient and donor pretransplantation HCMV serostatus. In 77 patients, first HCMV replication as detected by pp65-antigenemia assay developed at a median of 46 days (range, 25-108 days) after alloSCT. Taking all relevant competing risk factors into account, the cumulative incidence of hematologic relapse at 10 years after alloSCT was 42% (95% confidence interval [CI], 35%-51%) in patients without opposed to 9% (95% CI, 4%-19%) in patients with early pp65-antigenemia (P < .0001). A substantial and independent reduction of the relapse risk associated with early HCMV replication was confirmed by multivariate analysis using time-dependent covariate functions for grades II to IV acute and chronic graft-versus-host disease, and pp65-antigenemia (hazard ratio = 0.2; 95% CI, 0.1-0.4, P < .0001). This is the first report that demonstrates an independent and substantial reduction of the leukemic relapse risk after early replicative HCMV infection in a homogeneous population of adult acute myeloid leukemia patients.

scholarly journals Distinctive role of Stat3 and Erk-1/2 activation in mediating interferon-γ inhibition of TGF-β1 action

2006 ◽  
Vol 290 (5) ◽  
pp. F1234-F1240 ◽  
Author(s):  
Myrto Giannopoulou ◽  
Steven C. Iszkula ◽  
Chunsun Dai ◽  
Xiaoyue Tan ◽  
Junwei Yang ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Ectopic Expression ◽  
Interferon Γ ◽  
Signal Pathways ◽  
Tubular Epithelial Cells ◽  
Plasminogen Activator Inhibitor 1 ◽  
Ifn Γ ◽  
Pai 1

Interferon-γ (IFN-γ) is a multifunctional cytokine that elicits antifibrotic activity in a variety of organs. In this study, we investigated the potential role and mechanism of IFN-γ in modulating the fibrogenic action of transforming growth factor (TGF)-β1 in tubular epithelial cells. Incubation of human proximal tubular epithelial (HKC) cells with IFN-γ inhibited TGF-β1-mediated α-smooth muscle actin (α-SMA) expression. IFN-γ also abolished TGF-β1-induced fibronectin and plasminogen activator inhibitor-1 (PAI-1) expression. To explore the mechanisms by which INF-γ inhibits TGF-β1 action, the signaling pathways that are critical for mediating the antifibrotic activity of IFN-γ were studied. Stimulation of HKC cells with IFN-γ triggered a sustained activation of Erk-1/2 and signal transducer and activator of transcription-3 (Stat3). Blockade of Erk-1/2 activation with an Mek1 inhibitor abolished the inhibitory effect of IFN-γ on α-SMA expression, whereas inhibition of Stat3 activation had no influence. Constitutive activation of Erk-1/2 by ectopic expression of activated Mek1 mimicked IFN-γ and suppressed TGF-β1-mediated α-SMA expression. Interestingly, inhibition of Stat3 activation abolished the ability of IFN-γ to attenuate TGF-β1-mediated PAI-1 and fibronectin expression in HKC cells. These findings indicate that IFN-γ is capable of antagonizing the fibrogenic actions of TGF-β1 in renal tubular epithelial cells. The antifibrotic action of IFN-γ appears to be mediated through a coordinated activation of both Erk-1/2 and Stat3 signal pathways in a mutually independent fashion.

scholarly journals The Human Cytomegalovirus UL51 Protein Is Essential for Viral Genome Cleavage-Packaging and Interacts with the Terminase Subunits pUL56 and pUL89

2012 ◽  
Vol 87 (3) ◽  
pp. 1720-1732 ◽  
Author(s):  
Eva Maria Borst ◽  
Jennifer Kleine-Albers ◽  
Ildar Gabaev ◽  
Marina Babić ◽  
Karen Wagner ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Unit Length ◽  
Viral Proteins ◽  
Enzymatic Process ◽  
Genome Packaging ◽  
Subnuclear Localization ◽  
Promising Target ◽  
Synthetic Ligand ◽  
Infected Cells ◽  
Hcmv Replication

ABSTRACTCleavage of human cytomegalovirus (HCMV) genomes as well as their packaging into capsids is an enzymatic process mediated by viral proteins and therefore a promising target for antiviral therapy. The HCMV proteins pUL56 and pUL89 form the terminase and play a central role in cleavage-packaging, but several additional viral proteins, including pUL51, had been suggested to contribute to this process, although they remain largely uncharacterized. To study the function of pUL51 in infected cells, we constructed HCMV mutants encoding epitope-tagged versions of pUL51 and used a conditionally replicating virus (HCMV-UL51-ddFKBP), in which pUL51 levels could be regulated by a synthetic ligand. In cells infected with HCMV-UL51-ddFKBP, viral DNA replication was not affected when pUL51 was knocked down. However, no unit-length genomes and no DNA-filled C capsids were found, indicating that cleavage of concatemeric HCMV DNA and genome packaging into capsids did not occur in the absence of pUL51. pUL51 was expressed mainly with late kinetics and was targeted to nuclear replication compartments, where it colocalized with pUL56 and pUL89. Upon pUL51 knockdown, pUL56 and pUL89 were no longer detectable in replication compartments, suggesting that pUL51 is needed for their correct subnuclear localization. Moreover, pUL51 was found in a complex with the terminase subunits pUL56 and pUL89. Our data provide evidence that pUL51 is crucial for HCMV genome cleavage-packaging and may represent a third component of the viral terminase complex. Interference with the interactions between the terminase subunits by antiviral drugs could be a strategy to disrupt the HCMV replication cycle.

Superantigen immune stimulation activates epithelial STAT-1 and PI 3-K: PI 3-K regulation of permeability

2000 ◽  
Vol 279 (5) ◽  
pp. G1094-G1103 ◽  
Author(s):  
Derek M. McKay ◽  
Fernando Botelho ◽  
Peter J. M. Ceponis ◽  
Carl D. Richards
Keyword(s):  
Epithelial Cells ◽  
Conditioned Medium ◽  
Intracellular Signaling ◽  
Mononuclear Cells ◽  
Interferon Γ ◽  
Transepithelial Resistance ◽  
Mobility Shift ◽  
Peripheral Blood Mononuclear ◽  
Ussing Chambers ◽  
Ifn Γ

Signal transducers and activators of transcription (STATs) are critical intracellular signaling molecules for many cytokines. We compared the ability of T84 epithelial cells to activate STATs in response to cytokines [interferon-γ (IFN-γ), interleukin (IL)-4, IL-10, and tumor necrosis factor-α (10 ng/ml)] and conditioned medium from superantigen [ Staphylococcus aureus enterotoxin B (SEB)]-activated peripheral blood mononuclear cells (PBMC) using electrophoretic mobility shift assays (EMSA). Of the cytokines tested, only IFN-γ caused a STAT-1 response. Exposure to SEB-PBMC-conditioned medium resulted in STAT-1 or STAT-1/3 activation, and inclusion of anti-IFN-γ antibodies in the conditioned medium abolished the STAT-1 signal. Cells treated with transcription factor decoys, DNA oligonucleotides bearing the STAT-1 recognition motif, and then SEB-PBMC-conditioned medium displayed a reduced STAT-1 signal on EMSA, yet this treatment did not prevent the drop in transepithelial resistance (measured in Ussing chambers) caused by SEB-PBMC-conditioned medium. In contrast, the phosphatidylinositol 3′-kinase (PI 3-K) inhibitor LY-294002 significantly reduced the drop in transepithelial resistance caused by SEB-PBMC-conditioned medium. Thus data are presented showing STAT-1 (±STAT-3) and PI 3-K activation in epithelial cells in response to immune mediators released by superantigen immune activation. Although the involvement of STAT-1/-3 in the control of barrier function remains a possibility, PI-3K has been identified as a regulator of T84 paracellular permeability.

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