scholarly journals The Cytomegalovirus m155 Gene Product Subverts Natural Killer Cell Antiviral Protection by Disruption of H60–NKG2D Interactions

2004 ◽  
Vol 200 (8) ◽  
pp. 1075-1081 ◽  
Author(s):  
Melissa B. Lodoen ◽  
Gerardo Abenes ◽  
Sean Umamoto ◽  
Jeffrey P. Houchins ◽  
Fenyong Liu ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Proteasome Inhibitors ◽  
Mutant Virus ◽  
Murine Cytomegalovirus ◽  
Down Regulation ◽  
Mcmv Infection ◽  
Affinity Ligand

Natural killer (NK) cells are an important early mediator of host immunity to murine cytomegalovirus (MCMV) infection. However, MCMV has evolved mechanisms to elude recognition and clearance by NK cells. We have identified an MCMV immune evasion protein that impairs NKG2D-mediated NK cell antiviral activity. Infection of BALB/c 3T3 cells with the Smith strain of MCMV resulted in strong down-regulation of H60, a high affinity ligand for NKG2D, from the surface of virus-infected cells. The MCMV m155 protein specifically down-regulated H60 without affecting expression of the other known NKG2D ligands, RAE-1 and MULT-1. Treatment with the proteasome inhibitors lactacystin or epoxomicin reversed m155 down-regulation of H60. An MCMV mutant virus lacking m155 was severely attenuated in BALB/c mice; however, treatment with neutralizing anti-NKG2D monoclonal antibody or with NK-depleting anti-asialo GM1 antisera restored virulence of the mutant virus. Thus, down-regulation of H60 by m155 is a powerful mechanism of inhibiting NKG2D-mediated antiviral function.

scholarly journals The m15 Locus of Murine Cytomegalovirus Modulates Natural Killer Cell Responses to Promote Dissemination to the Salivary Glands and Viral Shedding

Pathogens ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 866
Author(s):  
Baca Chan ◽  
Maja Arapović ◽  
Laura Masters ◽  
Francois Rwandamuiye ◽  
Stipan Jonjić ◽  
...  
Keyword(s):  
Nk Cells ◽  
Salivary Glands ◽  
Natural Killer ◽  
Nk Cell ◽  
Acute Infection ◽  
Killer Cell ◽  
Viral Escape ◽  
Murine Cytomegalovirus ◽  
Viral Shedding ◽  
Cell Responses

As the largest herpesviruses, the 230 kb genomes of cytomegaloviruses (CMVs) have increased our understanding of host immunity and viral escape mechanisms, although many of the annotated genes remain as yet uncharacterised. Here we identify the m15 locus of murine CMV (MCMV) as a viral modulator of natural killer (NK) cell immunity. We show that, rather than discrete transcripts from the m14, m15 and m16 genes as annotated, there are five 3′-coterminal transcripts expressed over this region, all utilising a consensus polyA tail at the end of the m16 gene. Functional inactivation of any one of these genes had no measurable impact on viral replication. However, disruption of all five transcripts led to significantly attenuated dissemination to, and replication in, the salivary glands of multiple strains of mice, but normal growth during acute infection. Disruption of the m15 locus was associated with heightened NK cell responses, including enhanced proliferation and IFNγ production. Depletion of NK cells, but not T cells, rescued salivary gland replication and viral shedding. These data demonstrate the identification of multiple transcripts expressed by a single locus which modulate, perhaps in a concerted fashion, the function of anti-viral NK cells.

scholarly journals Inhibition of Enhancer of zeste homolog 2 (EZH2) induces natural killer cell-mediated eradication of hepatocellular carcinoma cells

2018 ◽  
Vol 115 (15) ◽  
pp. E3509-E3518 ◽  
Author(s):  
Suresh Bugide ◽  
Michael R. Green ◽  
Narendra Wajapeyee
Keyword(s):  
Hepatocellular Carcinoma ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Transcriptional Level ◽  
Dependent Manner ◽  
Down Regulation ◽  
Nkg2d Ligands ◽  
Enhancer Of Zeste

Natural killer (NK) cell-mediated tumor cell eradication could inhibit tumor initiation and progression. However, the factors that regulate NK cell-mediated cancer cell eradication remain unclear. We determined that hepatocellular carcinoma (HCC) cells exhibit transcriptional down-regulation of NK group 2D (NKG2D) ligands and are largely resistant to NK cell-mediated eradication. Because the down-regulation of NKG2D ligands occurred at the transcriptional level, we tested 32 chemical inhibitors of epigenetic regulators for their ability to re-express NKG2D ligands and enhance HCC cell eradication by NK cells and found that Enhancer of zeste homolog 2 (EZH2) was a transcriptional repressor of NKG2D ligands. The inhibition of EZH2 by small-molecule inhibitors or genetic means enhanced HCC cell eradication by NK cells in a NKG2D ligand-dependent manner. Collectively, these results demonstrate that EZH2 inhibition enhances HCC eradication by NK cells and that EZH2 functions, in part, as an oncogene by inhibiting immune response.

scholarly journals Proinflammatory cytokine signaling required for the generation of natural killer cell memory

2012 ◽  
Vol 209 (5) ◽  
pp. 947-954 ◽  
Author(s):  
Joseph C. Sun ◽  
Sharline Madera ◽  
Natalie A. Bezman ◽  
Joshua N. Beilke ◽  
Mark H. Kaplan ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Interleukin 12 ◽  
Cytokine Signaling ◽  
Mcmv Infection ◽  
Ifn Γ ◽  
Deficient Mice ◽  
Memory Nk Cells

Although natural killer (NK) cells are classified as innate immune cells, recent studies demonstrate that NK cells can become long-lived memory cells and contribute to secondary immune responses. The precise signals that promote generation of long-lived memory NK cells are unknown. Using cytokine receptor-deficient mice, we show that interleukin-12 (IL-12) is indispensible for mouse cytomegalovirus (MCMV)-specific NK cell expansion and generation of memory NK cells. In contrast to wild-type NK cells that proliferated robustly and resided in lymphoid and nonlymphoid tissues for months after MCMV infection, IL-12 receptor–deficient NK cells failed to expand and were unable to mediate protection after MCMV challenge. We further demonstrate that a STAT4-dependent IFN-γ–independent mechanism contributes toward the generation of memory NK cells during MCMV infection. Understanding the full contribution of inflammatory cytokine signaling to the NK cell response against viral infection will be of interest for the development of vaccines and therapeutics.

scholarly journals Natural Killer Cells Utilize both Perforin and Gamma Interferon To Regulate Murine Cytomegalovirus Infection in the Spleen and Liver

2005 ◽  
Vol 79 (1) ◽  
pp. 661-667 ◽  
Author(s):  
Joy Loh ◽  
Dortha T. Chu ◽  
Andrew K. O'Guin ◽  
Wayne M. Yokoyama ◽  
Herbert W. Virgin
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Acute Phase ◽  
Nk Cell ◽  
Gamma Interferon ◽  
Murine Cytomegalovirus ◽  
Mcmv Infection ◽  
Independent Manner ◽  
Organ Specific ◽  
Ifn Γ

ABSTRACT Natural killer (NK) cells are critical for innate regulation of the acute phase of murine cytomegalovirus (MCMV) infection and have been reported to utilize perforin (Pfp)- and gamma interferon (IFN-γ)-dependent effector mechanisms in an organ-specific manner to regulate MCMV infection in the spleen and liver. In this study, we further examined the roles of NK cells, Pfp, and IFN-γ in innate immunity to MCMV infection. With the recently described NK cell-deficient (NKD) mouse, we confirmed previous findings that NK cells, but not NKT cells, are required for control of the acute phase of MCMV infection in spleen and liver cells. Interestingly, we found that Pfp and IFN-γ are each important for regulating MCMV replication in both the spleen and the liver. Moreover, NK cells can regulate MCMV infection in the spleens and livers of Pfp−/− mice in a Pfp-independent manner and can use an IFN-γ-independent mechanism to control MCMV infection in IFN-γ−/− mice. Thus, contrary to previous reports, NK cells utilize both Pfp and IFN-γ to control MCMV infection in the spleen and liver.

scholarly journals Metabolic but not transcriptional regulation by PKM2 is important for natural killer cell responses

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Jessica F Walls ◽  
Jeff J Subleski ◽  
Erika M Palmieri ◽  
Marieli Gonzalez-Cotto ◽  
Clair M Gardiner ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Nk Cells ◽  
Natural Killer ◽  
Transcriptional Control ◽  
Nk Cell ◽  
Cell Metabolism ◽  
Killer Cell ◽  
Glycolytic Enzyme ◽  
Glycolytic Flux ◽  
Mcmv Infection

Natural Killer (NK) cells have an important role in immune responses to viruses and tumours. Integrating changes in signal transduction pathways and cellular metabolism is essential for effective NK cells responses. The glycolytic enzyme Pyruvate Kinase Muscle 2 (PKM2) has described roles in regulating glycolytic flux and signal transduction, particularly gene transcription. While PKM2 expression is robustly induced in activated NK cells, mice lacking PKM2 in NK cells showed no defect in NK cell metabolism, transcription or antiviral responses to MCMV infection. NK cell metabolism was maintained due to compensatory PKM1 expression in PKM2-null NK cells. To further investigate the role of PKM2, we used TEPP-46, which increases PKM2 catalytic activity while inhibiting any PKM2 signalling functions. NK cells activated with TEPP-46 had reduced effector function due to TEPP-46-induced increases in oxidative stress. Overall, PKM2-regulated glycolytic metabolism and redox status, not transcriptional control, facilitate optimal NK cells responses.

scholarly journals Metabolic but not transcriptional regulation by PKM2 is important for Natural Killer cell responses

2020 ◽  
Author(s):  
Jessica F. Walls ◽  
Jeff J. Subleski ◽  
Erika M. Palmieri ◽  
Marieli Gonzalez Cotto ◽  
Clair M. Gardiner ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Nk Cells ◽  
Natural Killer ◽  
Transcriptional Control ◽  
Immune Cell ◽  
Nk Cell ◽  
Killer Cell ◽  
Glycolytic Enzyme ◽  
Glycolytic Flux ◽  
Mcmv Infection

AbstractNatural Killer (NK) cells have an important role in immune responses to viruses and tumours. Integrating changes in signal transduction pathways and cellular metabolism is essential for effective NK cells responses. The PKM2 isoform of the glycolytic enzyme Pyruvate Kinase Muscle has described roles in regulating glycolytic flux and signal transduction, especially gene transcription. While PKM2 expression is robustly induced in activated NK cells, mice lacking PKM2 in NK cells showed no defect in NK cell metabolism or anti-viral responses to MCMV infection. This maintenance of function is explained by compensatory PKM1 expression in PKM2-null NK cell cells demonstrating that PKM2 is not a signalling molecule in this immune cell type. To further investigate the role of PKM2 we forced the tetramerization of the protein with TEPP-46, which increases its catalytic activity while inhibiting any signalling functions mediated by mono/dimeric conformations. NK cells activated with TEPP-46 had reduced effector function due to TEPP-46-induced increases in oxidative stress. Overall, PKM2-regulated glycolytic metabolism and redox status, not transcriptional control, facilitate optimal NK cells responses.

Carfilzomib Enhances Natural Killer Cell-Mediated Lysis of Myeloma Linked with Decreasing Expression of HLA Class I

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1854-1854
Author(s):  
Jumei Shi ◽  
Guang Yang ◽  
Yuanyuan Kong ◽  
Minjie Gao ◽  
Yi Tao ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Nk Cells ◽  
Natural Killer ◽  
Hematological Malignancies ◽  
Nk Cell ◽  
Killer Cell ◽  
Hla Class I ◽  
Class I ◽  
Dependent Manner ◽  
Down Regulation

Abstract Multiple myeloma (MM) is a malignant disorder characterized by uncontrolled monoclonal plasma cell proliferation. It accounts for 10% of all hematological malignancies and causes 15-20% of deaths from hematological malignancies. Although new therapies were introduced and overall survival of MM was improved in the last 10 years, MM still remains an incurable disease due to drug resistance. Natural killer (NK) cell-based treatments are promising therapies for multiple myeloma (MM). Carfilzomib (CFZ), a second-generation proteasome inhibitor, is used to treat patients with MM who are refractory or intolerant to both bortezomib and lenalidomide (or thalidomide). In this study, we determined that CFZ treatment enhanced the sensitivity of MM cells to NK cell-mediated lysis. Here, we report that CFZ decreased the expression of human leukocyte antigen (HLA) class I on MM cell lines and primary MM cells, the mean reduction was 47.7 ± 9.4% and 42.8 ± 12.4%, respectively. The down-regulation caused by CFZ occurred in a dose- and time- dependent manner. We compared the cell surface levels of HLA class I on MM cells in the presence or absence of CFZ after acid treatment. CFZ also down-regulated the expression of newly formed HLA class I on MM cells. CD107a expression levels were used to measure NK-cell degranulation. When NK cells were incubated with MM cells with CFZ treatment, the percentage of NK cells expressing CD107a on the surface greatly increased (mean ± SD: 33.6 ± 2.1%, for treated cells vs 16.7 ± 2.3%, for control cells, P < 0.05). We also showed that CFZ augmented NK-cell cytotoxity by a perforin/granzyme-mediated mechanism, because such enhancement was abolished when CMA, but not anti-TRAIL or anti-Fas-L antibodies, was added. Treatment of MM with CFZ significantly sensitized patients' MM cells to NK cell-mediated lysis (mean ± SD: 43.1 ± 6.4%, for treated cells vs 16.1 ± 4.0%, for control cells at effector/target (E/T) ratio of 10:1, n = 9, P < 0.01). Furthermore, the exogenous HLA-C binding peptides, used in the CFZ treated group rescued the down-regulation of HLA-C and reduced NK cell-mediated lysis to a similar level as in the untreated group. Blocking NKG2D, NCRs and TRAIL did not have a significant impact on NK cell lysis of myeloma cells. These implied the enhancement of NK cell-mediated lysis was mainly linked with the decreased expression of HLA class I. Our findings show a novel activity of CFZ as an immunomodulating agent and suggest a possible approach to therapeutically augment NK cell function in MM patients. Disclosures No relevant conflicts of interest to declare.

scholarly journals Induction of Natural Killer Cell Responses by Ectromelia Virus Controls Infection

2007 ◽  
Vol 81 (8) ◽  
pp. 4070-4079 ◽  
Author(s):  
April Keim Parker ◽  
Scott Parker ◽  
Wayne M. Yokoyama ◽  
John A. Corbett ◽  
R. Mark L. Buller
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Intracellular Cytokine Staining ◽  
Killer Cell ◽  
Murine Cytomegalovirus ◽  
Virus Infectivity ◽  
Ectromelia Virus ◽  
Ifn Γ

ABSTRACT Natural killer (NK) cells play a pivotal role in the innate immune response to viral infections, particularly murine cytomegalovirus (MCMV) and human herpesviruses. In poxvirus infections, the role of NK cells is less clear. We examined disease progression in C57BL/6 mice after the removal of NK cells by both antibody depletion and genetic means. We found that NK cells were crucial for survival and the early control of virus replication in spleen and to a lesser extent in liver in C57BL/6 mice. Studies of various knockout mice suggested that γδ T cells and NKT cells are not important in the C57BL/6 mousepox model and CD4+ and CD8+ T cells do not exhibit antiviral activity at 6 days postinfection, when the absence of NK cells has a profound effect on virus titers in spleen and liver. NK cell cytotoxicity and/or gamma interferon (IFN-γ) secretion likely mediated the antiviral effect needed to control virus infectivity in target organs. Studies of the effects of ectromelia virus (ECTV) infection on NK cells demonstrated that NK cells proliferate within target tissues (spleen and liver) and become activated following a low-dose footpad infection, although the mechanism of activation appears distinct from the ligand-dependent activation observed with MCMV. NK cell IFN-γ secretion was detected by intracellular cytokine staining transiently at 32 to 72 h postinfection in the lymph node, suggesting a role in establishing a Th1 response. These results confirm a crucial role for NK cells in controlling an ECTV infection.

scholarly journals Pivotal Role of KARAP/DAP12 Adaptor Molecule in the Natural Killer Cell–mediated Resistance to Murine Cytomegalovirus Infection

2002 ◽  
Vol 195 (7) ◽  
pp. 825-834 ◽  
Author(s):  
Hanna Sjölin ◽  
Elena Tomasello ◽  
Mehrdad Mousavi-Jazi ◽  
Armando Bartolazzi ◽  
Klas Kärre ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Interferon Γ ◽  
Mutant Mice ◽  
Murine Cytomegalovirus ◽  
Activating Receptors ◽  
And Function

Natural killer (NK) cells are major contributors to early defense against infections. Their effector functions are controlled by a balance between activating and inhibiting signals. To date, however, the involvement of NK cell activating receptors and signaling pathways in the defense against pathogens has not been extensively investigated. In mice, several NK cell activating receptors are coexpressed with and function through the immunoreceptor tyrosine-based activation motif (ITAM)-bearing molecule KARAP/DAP12. Here, we have analyzed the role of KARAP/DAP12 in the early antiviral response to murine cytomegalovirus (MCMV). In KARAP/DAP12 mutant mice bearing a nonfunctional ITAM, we found a considerable increase in viral titers in the spleen (30–40-fold) and in the liver (2–5-fold). These effects were attributed to NK cells. The formation of hepatic inflammatory foci appeared similar in wild-type and mutant mice, but the latter more frequently developed severe hepatitis with large areas of focal necrosis. Moreover, the percentage of hepatic NK cells producing interferon γ was reduced by 56 ± 22% in the absence of a functional KARAP/DAP12. This is the first study that shows a crucial role for a particular activating signaling pathway, in this case the one induced through KARAP/DAP12, in the NK cell–mediated resistance to an infection. Our results are discussed in relation to recent reports demonstrating that innate resistance to MCMV requires the presence of NK cells expressing the KARAP/DAP12-associated receptor Ly49H.

scholarly journals Early Murine Cytomegalovirus (MCMV) Infection Induces Liver Natural Killer (NK) Cell Inflammation and Protection Through Macrophage Inflammatory Protein 1α (MIP-1α)–dependent Pathways

1998 ◽  
Vol 187 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Thais P. Salazar-Mather ◽  
Jordan S. Orange ◽  
Christine A. Biron
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Viral Infections ◽  
Inflammatory Responses ◽  
Nk Cell ◽  
Murine Cytomegalovirus ◽  
Liver Inflammation ◽  
Mcmv Infection ◽  
Inflammatory Protein ◽  
Macrophage Inflammatory Protein

Natural killer (NK) cells mediate defense against early murine cytomegalovirus (MCMV) infections in liver. The chemokine, macrophage inflammatory protein 1α (MIP-1α), can promote inflammatory responses. Our studies evaluated contributions of NK cells to early MCMV-induced liver inflammation and MIP-1α requirements for inflammation and delivery of antiviral defenses. NK cells were shown to be responsible for focal inflammation, and to be induced to migrate at high levels, in MCMV-infected livers. MIP-1α gene expression was elevated at coinciding times, and mice deficient in MIP-1α function were dramatically inhibited in both inflammatory and protective liver responses. The results precisely define MIP-1α–dependent steps required to achieve NK cell inflammation during, and mechanisms promoting defense against, viral infections in tissues.

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