scholarly journals NK cell–activating receptors require PKC-θ for sustained signaling, transcriptional activation, and IFN-γ secretion

Blood ◽  
2008 ◽  
Vol 112 (10) ◽  
pp. 4109-4116 ◽  
Author(s):  
Ilaria Tassi ◽  
Marina Cella ◽  
Rachel Presti ◽  
Angela Colucci ◽  
Susan Gilfillan ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Nk Cell ◽  
Cell Secretion ◽  
Surface Receptors ◽  
Intracellular Signals ◽  
Activating Receptors ◽  
Infected Cells ◽  
Multiple Cell ◽  
Ifn Γ ◽  
Extracellular Regulated Kinase

AbstractNatural killer (NK) cell sense virally infected cells and tumor cells through multiple cell surface receptors. Many NK cell–activating receptors signal through immunoreceptor tyrosine–based activation motif (ITAM)–containing adapters, which trigger both cytotoxicy and secretion of interferon-gamma (IFN-γ). Within the ITAM pathway, distinct signaling intermediates are variably involved in cytotoxicity and/or IFN-γ secretion. In this study, we have evaluated the role of protein kinase C-θ (PKC-θ) in NK-cell secretion of lytic mediators and IFN-γ. We found that engagement of NK-cell receptors that signal through ITAMs results in prompt activation of PKC-θ. Analyses of NK cells from PKC-θ–deficient mice indicated that PKC-θ is absolutely required for ITAM-mediated IFN-γ secretion, whereas it has no marked influence on the release of cytolytic mediators. Moreover, we found that PKC-θ deficiency preferentially impairs sustained extracellular-regulated kinase signaling as well as activation of c-Jun N-terminal kinase and the transcription factors AP-1 and NFAT but does not affect activation of NF-κB. These results indicate that NK cell–activating receptors require PKC-θ to generate sustained intracellular signals that reach the nucleus and promote transcriptional activation, ultimately inducing IFN-γ production.

scholarly journals Nonameric Peptide Orchestrates Signal Transduction in the Activating HLA-E/NKG2C/CD94 Immune Complex as Revealed by All-Atom Simulations

2021 ◽  
Vol 22 (13) ◽  
pp. 6670
Author(s):  
Eva Prašnikar ◽  
Andrej Perdih ◽  
Jure Borišek
Keyword(s):  
Signal Transduction ◽  
Cell Activation ◽  
Nk Cell ◽  
Innate Immune ◽  
Target Cells ◽  
Molecular Events ◽  
Activating Receptors ◽  
Molecular Machinery ◽  
Infected Cells ◽  
Bond Network

The innate immune system’s natural killer (NK) cells exert their cytolytic function against a variety of pathological challenges, including tumors and virally infected cells. Their activation depends on net signaling mediated via inhibitory and activating receptors that interact with specific ligands displayed on the surfaces of target cells. The CD94/NKG2C heterodimer is one of the NK activating receptors and performs its function by interacting with the trimeric ligand comprised of the HLA-E/β2m/nonameric peptide complex. Here, simulations of the all-atom multi-microsecond molecular dynamics in five immune complexes provide atomistic insights into the receptor–ligand molecular recognition, as well as the molecular events that facilitate the NK cell activation. We identify NKG2C, the HLA-Eα2 domain, and the nonameric peptide as the key elements involved in the molecular machinery of signal transduction via an intertwined hydrogen bond network. Overall, the study addresses the complex intricacies that are necessary to understand the mechanisms of the innate immune system.

scholarly journals Effect of interleukins (IL-2, IL-15, IL-18) on receptors activation and cytotoxic activity of natural killer cells in breast cancer cell

2020 ◽  
Vol 20 (2) ◽  
pp. 822-832 ◽  
Author(s):  
Wahyu Widowati ◽  
Diana K Jasaputra ◽  
Sutiman B Sumitro ◽  
Mochammad A Widodo ◽  
Tjandrawati Mozef ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cytotoxic Activity ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Cell Receptor ◽  
Mcf7 Cells ◽  
Activating Receptors ◽  
Tnf Α ◽  
Ifn Γ

Introduction: Breast cancer is one of the leading cause of cancer deaths in women. Metastasis in BC is caused by immuno- surveillance deficiency, such NK cell maturation, low NK activity and decreasing cytotoxicity. This study was performed to improve activating receptors and cytotoxicity of NK cells using interleukins (ILs). Methods: Human recombinant IL-2, -15, and -18 were used to induce NK cells. We measured the activating and inhibiting receptors, proliferation activity of NK cells, and the cytotoxicity of NK cells on BC cells (MCF7). The effects of ILs were tested on the NK cell receptors CD314, CD158a and CD107a with flowcytometry, proliferation at various incubation times with 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and concen- trations of TNF-α and IFN-γ by NK cells with ELISA. Results: ILs increased NK cell receptor levels (CD314, CD158a, and CD107a) at 24 hours of incubation. ILs increased NK cell viability, which increased with longer incubation. Moreover, ILs-induced NK cells inhibited proliferation in MCF7 cells, as well as increased TNF-α, IFN-γ, PRF1 and GzmB secretion. Conclusion: IL-2, IL-15, and IL-18 improved activating receptors and proliferation of NK cells. IL-induced NK cells in- creased TNF-α, IFN-γ, PRF1 and GzmB secretion and cytotoxic activity on BC cells. High NK cell numbers increased BC cell growth inhibition. Keywords: Activator; breast cancer; interleukins; natural killer; receptor.

scholarly journals Functional Dichotomy in Natural Killer Cell Signaling

2001 ◽  
Vol 193 (12) ◽  
pp. 1413-1424 ◽  
Author(s):  
Francesco Colucci ◽  
Eleftheria Rosmaraki ◽  
Søren Bregenholt ◽  
Sandrine I. Samson ◽  
Vincenzo Di Bartolo ◽  
...  
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Killer Cell ◽  
Surface Receptors ◽  
Nk T Cells ◽  
Nk Cell Differentiation ◽  
Ifn Γ

The product of the protooncogene Vav1 participates in multiple signaling pathways and is a critical regulator of antigen–receptor signaling in B and T lymphocytes, but its role during in vivo natural killer (NK) cell differentiation is not known. Here we have studied NK cell development in Vav1−/− mice and found that, in contrast to T and NK-T cells, the absolute numbers of phenotypically mature NK cells were not reduced. Vav1−/− mice produced normal amounts of interferon (IFN)-γ in response to Listeria monocytogenes and controlled early infection but showed reduced tumor clearance in vivo. In vitro stimulation of surface receptors in Vav1−/− NK cells resulted in normal IFN-γ production but reduced tumor cell lysis. Vav1 was found to control activation of extracellular signal-regulated kinases and exocytosis of cytotoxic granules. In contrast, conjugate formation appeared to be only mildly affected, and calcium mobilization was normal in Vav1−/− NK cells. These results highlight fundamental differences between proximal signaling events in T and NK cells and suggest a functional dichotomy for Vav1 in NK cells: a role in cytotoxicity but not for IFN-γ production.

scholarly journals TIGIT Expression Positively Associates with NK Cell Function in AML Patients

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5250-5250 ◽  
Author(s):  
Bei Jia ◽  
Chenchen Zhao ◽  
David F. Claxton ◽  
W. Christopher Ehmann ◽  
Witold B. Rybka ◽  
...  
Keyword(s):  
Nk Cells ◽  
Therapeutic Strategy ◽  
Cell Function ◽  
Nk Cell ◽  
Granzyme B ◽  
Healthy Controls ◽  
Functional Studies ◽  
Activating Receptors ◽  
Tnf Α ◽  
Ifn Γ

Abstract Natural killer (NK) cells are essential innate immune effectors with promising anti-leukemia activity in acute myeloid leukemia (AML). However, clinical success of applying NK cells in AML treatment has not been achieved. A better understanding of the regulatory mechanisms for NK cell function is important to optimize this therapeutic strategy. T cell immunoglobulin and ITIM domain (TIGIT) is a recently identified inhibitory receptor expressed on T cells and NK cells. Multiple studies including ours have demonstrated its suppressive effect in anti-tumor CD8 T cell response. However whether and how TIGIT impacts NK cells in AML is unknown. Here we performed phenotypic and functional studies on NK cells derived from patients with newly diagnosed AML (n=30). Cells collected from healthy individuals (n=18) were used as controls. TIGIT expression and their contributions to NK cell function in AML were assessed. Peripheral blood samples were first examined by flow cytometry for the frequency of NK cells (defined as CD56+CD3-). The percentage of NK cells among peripheral blood mononuclear cells (PBMCs) in AML patients is comparable with that of healthy controls. In contrast, when we performed functional analysis to assess NK cells for cytokine release upon in vitro stimulation with a human leukemia cell line K562, we observed significantly lower intracellular production of IFN-γ in cells from AML patients compared with that of healthy controls. Consistently NK cells from AML patients expressed less Perforin, indicating a compromised killing capacity. We next evaluated the expression of TIGIT on CD56+CD3- NK cells. As some AML blasts and monocytes also express CD56, we performed multichannel flow cytometry and carefully gated out other cell components when assessing TIGIT expression. To our surprise, we observed a significantly lower frequency of TIGIT-expressing NK cells in AML compared with that of healthy controls (36.82 ±4.543% vs. 48.9±3.818%, P=0.0463). This data indicated that low-TIGIT expression associates with impaired NK cell function and AML progression. We further examined the phenotype and functional status of TIGIT+ NK cells. Expression of activating receptors (CD16 and CD160) and inhibiting receptors (KIR and NKG2A) on TIGIT+ vs. TIGIT- NK cells were analyzed. We observed a significant higher expression of CD16 (51.27±9.009% vs. 20.63±5.334%, P=0.0001) and CD160 (39.84±6.447% vs. 21.24±4.287%, P=0.0103) on TIGIT+ NK cells compared with that of TIGIT- NK cells. By contrast, TIGIT+ NK cells expressed lower KIR (24.06±3.796% vs. 43.59±6.96%, P=0.0046) and NKG2A (7.658±1.717% vs. 18.68±4.256%, P=0.0167) than TIGIT- NK cells. Importantly, functional studies demonstrated an elevated expression of Granzyme B and increased cytokine (IFN-γ and TNF-α) production by TIGIT+ NK cells compared with TIGIT- NK cells (IFN-γ, P=0.0283; TNF-α P=0.0347; Granzyme B, P=0.0493). These data suggest that TIGIT expression on NK cells associated with activated and high functional status. Collectively, our study demonstrates that 1) in line with lower capacity to produce IFN-γ, NK cells from AML patients express less frequency of TIGIT compared with healthy individuals; 2) TIGIT+ NK cells from AML patients express high levels of activating receptors and are highly functional manifested by more cytokine production and enhanced expression of Granzyme B compared with TIGIT- NK cells. These results indicate that in AML patient, TIGIT may contribute to the upregulation of NK cell function. This is in contrast to the observations of CD8 T cells in which TIGIT plays a suppressive role. Targeting TIGIT for cancer treatment is currently under active development. Our findings bring a call for caution on the TIGIT-targeted therapeutic strategy in AML as TIGIT might be a double-edged sword in anti-leukemia immune regulation. Disclosures No relevant conflicts of interest to declare.

scholarly journals Virus-specific NK cell memory

2021 ◽  
Vol 218 (4) ◽  
Author(s):  
Sam Sheppard ◽  
Joseph C. Sun
Keyword(s):  
Nk Cells ◽  
Cytomegalovirus Infection ◽  
Cytokine Production ◽  
Nk Cell ◽  
Transformed Cells ◽  
Surface Receptors ◽  
Clonal Proliferation ◽  
Cell Clones ◽  
Memory Pool ◽  
Infected Cells

NK cells express a limited number of germline-encoded receptors that identify infected or transformed cells, eliciting cytotoxicity, effector cytokine production, and in some circumstances clonal proliferation and memory. To maximize the functional diversity of NK cells, the array and expression level of surface receptors vary between individual NK cell “clones” in mice and humans. Cytomegalovirus infection in both species can expand a population of NK cells expressing receptors critical to the clearance of infected cells and generate a long-lived memory pool capable of targeting future infection with greater efficacy. Here, we discuss the pathways and factors that regulate the generation and maintenance of effector and memory NK cells and propose how this understanding may be harnessed therapeutically.

scholarly journals Research Progress on NK Cell Receptors and Their Signaling Pathways

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yingying Chen ◽  
Dan Lu ◽  
Alexey Churov ◽  
Rong Fu
Keyword(s):  
Cell Surface ◽  
Nk Cells ◽  
Signaling Pathways ◽  
Nk Cell ◽  
Research Progress ◽  
Inhibitory Receptors ◽  
Cell Receptors ◽  
Surface Receptors ◽  
Nk Cell Receptors ◽  
Activating Receptors

Natural killer cells (NK cells) play an important role in innate immunity. NK cells recognize self and nonself depending on the balance of activating receptors and inhibitory receptors. After binding to their ligands, NK cell receptors trigger subsequent signaling conduction and then determine whether NK is activated or inhibited. Furthermore, NK cell response includes cytotoxicity and cytokine release, which is tightly related to the activation of NK cell-activating receptors and the inhibition of inhibitory receptors on the surfaces of NK cells. The expression and function of NK cell surface receptors also alter in virus infection, tumor, and autoimmune diseases and influence the occurrence and development of diseases. So, it is important to understand the mechanism of recognition between NK receptors and their ligands in pathological conditions and the signaling pathways of NK cell receptors. This review mainly summarizes the research progress on NK cell surface receptors and their signal pathways.

scholarly journals Inhibition of Interferon Signaling by Rabies Virus Phosphoprotein P: Activation-Dependent Binding of STAT1 and STAT2

2006 ◽  
Vol 80 (6) ◽  
pp. 2675-2683 ◽  
Author(s):  
Krzysztof Brzózka ◽  
Stefan Finke ◽  
Karl-Klaus Conzelmann
Keyword(s):  
Rabies Virus ◽  
Transcriptional Activation ◽  
Type I ◽  
Interferon Signaling ◽  
Cell Extracts ◽  
Independent Functions ◽  
Stat Signaling ◽  
Infected Cells ◽  
Ifn Γ ◽  
In Cells

ABSTRACT Rabies virus (RV) phosphoprotein P is an interferon (IFN) antagonist counteracting transcriptional activation of type I IFN (K. Brzózka, S. Finke, and K. K. Conzelmann, J. Virol 79:7673-7681, 2005). We here show that RV P in addition is responsible for preventing IFN-α/β- and IFN-γ-stimulated JAK-STAT signaling in RV-infected cells by the retention of activated STATs in the cytoplasm. Expression of IFN-stimulated response element- and gamma-activated sequence-controlled genes was severely impaired in cells infected with RV SAD L16 or in cells expressing RV P protein from transfected plasmids. In contrast, a recombinant RV expressing small amounts of P had lost the ability to interfere with JAK-STAT signaling. IFN-mediated tyrosine phosphorylation of STAT1 and STAT2 was not impaired in RV P-expressing cells; rather, a defect in STAT recycling was suggested by distinct accumulation of tyrosine-phosphorylated STATs in cell extracts. In the presence of P, activated STAT1 and STAT2 were unable to accumulate in the nucleus. Notably, STAT1 and STAT2 were coprecipitated with RV P only from extracts of cells previously stimulated with IFN-α or IFN-γ, whereas in nonstimulated cells no association of P with STATs was observed. This conditional, IFN activation-dependent binding of tyrosine-phosphorylated STATs by RV P is unique for a viral IFN antagonist. The 10 C-terminal residues of P are required for counteracting JAK-STAT signaling but not for inhibition of transcriptional activation of IFN-β, thus demonstrating two independent functions of RV P in counteracting the host's IFN response.

scholarly journals Antineoplastic and anti-inflammatory effects of bortezomib on systemic chronic active EBV infection

2021 ◽  
Vol 5 (7) ◽  
pp. 1805-1815
Author(s):  
Mayumi Yoshimori ◽  
Haruna Shibayama ◽  
Ken-Ichi Imadome ◽  
Fuyuko Kawano ◽  
Ayaka Ohashi ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Lines ◽  
Messenger Rna ◽  
Mononuclear Cells ◽  
Nk Cell ◽  
Intraperitoneal Administration ◽  
Hematopoietic Stem ◽  
Tnf Α ◽  
Infected Cells ◽  
Ifn Γ

Abstract Systemic chronic active Epstein-Barr virus (EBV; sCAEBV) infection, T- and natural killer (NK)-cell type (sCAEBV), is a fatal disorder accompanied by persisting inflammation harboring clonal proliferation of EBV-infected T or NK cells. Today’s chemotherapy is insufficient to resolve disease activity and to rid infected cells of sCAEBV. The currently established treatment strategy for eradicating infected cells is allogeneic hematopoietic stem cell transplantation. In this study, we focused on the effects of proteasome inhibitor bortezomib on the disease. Bortezomib suppressed survival and induced apoptosis of EBV+ T- or NK-cell lines and peripheral mononuclear cells containing EBV-infected T or NK cells of sCAEBV patients. Bortezomib enhanced binding immunoglobulin protein/78-kDa glucose-regulated protein (Bip/GRP78) expression induced by endoplasmic reticulum stress and activated apoptosis-promoting molecules JNK and p38 in the cell lines. Bortezomib suppressed the activation of survival-promoting molecule NF-κB, which was constitutively activated in EBV+ T- or NK-cell lines. Furthermore, quantitative reverse transcription–polymerase chain reaction demonstrated that bortezomib suppressed messenger RNA expression of proinflammatory cytokines tumor necrosis factor α (TNF-α) and interferon γ (IFN-γ) in EBV+ T or NK cells from the patients. Finally, we examined the effects of bortezomib using xenograft models of sCAEBV generated by IV injection of patients’ cells. The intraperitoneal administration of bortezomib significantly reduced EBV-DNA load in peripheral blood and the infiltration of EBV-infected cells in the models’ livers. Moreover, the serum concentration of TNF-α and IFN-γ decreased after bortezomib treatment to the models. Our findings will be translated into the treatment of sCAEBV not only to reduce the number of tumor cells but also to suppress inflammation.

Copies of Donor Killer Immunoglobulin-like Receptor Genes and Motifs Titrate Natural Killer (NK) Cells' Functional Response to Epstein - Barr Virus Infections and Influence the Risk of Developing Post-Transplant Lymphoproliferative Disease (PTLD) after Allogeneic Hematopoietic Cell Transplantation

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 741-741
Author(s):  
Rehan Mujeeb Faridi ◽  
Taylor J Kemp ◽  
Poonam Dharmani ◽  
Victor A. Lewis ◽  
Noureddine Berka ◽  
...  
Keyword(s):  
Nk Cells ◽  
Functional Response ◽  
Epstein Barr Virus ◽  
Viral Infections ◽  
Nk Cell ◽  
Barr Virus ◽  
Infected Cells ◽  
Ifn Γ ◽  
Epstein Barr ◽  
Kir Gene

Abstract BACKGROUND: Recipientsof allogeneic HCT remain vulnerable to a heightened risk of reactivation of otherwise latent viral infections owing to a compromised immune system early after transplantation. Uncontrolled reactivation of Epstein-Barr virus (EBV) leading to post-transplant lymphoproliferative disorder (PTLD) is one of such major complications after T-cell depleted HCT. Recovering within weeks after transplantation and being first in line of defense against viral infections, natural killer (NK) cells are deemed important in the immunopathogenesis of EBV complications. Their role however remains elusive. NK cell responses are regulated by a series of activating and inhibitory cell surface receptors, central to which are the Killer Immunoglobulin-like Receptors (KIR). Through these receptors NK cells discriminate healthy cells from 'altered' self-cells by scaling the perturbations in HLA expression after viral transformation of the target cell. Here, we set out to determine whether and how KIR gene and motifs' content of HCT donors and/or recipients influences the development of PTLD after allo-HCT. STUDY DESIGN: Hypothesizing that diverse NK cell receptor repertoires can titrate NK cell functional responses to EBV infections/reactivation and can potentially modify the risk of developing PTLD, we determined the KIR gene repertoires of 356 HLA-matched donor-recipient pairs of first allo-HCT and 50 healthy donors through Next Generation Sequencing of the KIR locus on the Illumina MiSeq platform. Based on the presence/absence and number of copies of individual genes, the KIR genotypes were determined and classified into four common centromeric (cA01, cB01, cB02 and cB03) and two telomeric (tA01 and tB01) motifs along with their variants. PBMNCs from KIR typed healthy volunteers were stimulated with EBV-transformed target cells to enumerate NK cell response to EBV (degranulation and/or IFNγ production) as a function of KIR gene content and motifs' distribution using a multicolor flow cytometry-based assay. Effect of KIR gene profile on development of PTLD was analyzed using binomial competing risks regression statistics. Distribution of NK cell functional response across various KIR characterized groups was analyzed using Mann-Whitney U statistics. RESULTS: Donor telomeric A motifs (tA01, KIR3DL1+ve KIR2DS4+ve; KIR3DS1/2DS1+/-ve), strongly protected against PTLD (p=0.0001, SHR=0.17; Figure 1). An increased protection against PTLD with increasing number of tA01 was noted with at least one copy required for a significant protective effect (Figure 1B). Copy number analysis of tA01 gene contents yielded similar associations. Further, the number of EBV induced functional NK cell subsets were significantly higher in individuals with than without KIR genotypes containing tA01 motifs (Figure 2 A-C) and was found to be increasing with an increasing number of tA01 copies (Figure 2 A'-C'). There was no influence of recipients' KIR repertoire on the risk of developing PTLD CONCLUSIONS: NK cell responsiveness, a function of KIR gene repertoire has a profound effect on the development of PTLD. Appropriately characterized KIR gene profile based identification of HCT recipients at high risk of developing PTLD will enable closer monitoring of EBV DNAemia and facilitate prompt therapy. Figure 1. Donor KIR telomeric A motif (tA01) protects against the risk of developing PTLD (A). Presence of at least one copy of donor KIR tA01 motif confers significant protection from PTLD (B) Figure 1. Donor KIR telomeric A motif (tA01) protects against the risk of developing PTLD (A). Presence of at least one copy of donor KIR tA01 motif confers significant protection from PTLD (B) Figure 2. KIR telomeric A motifs (tA01) titrate NK cells' functional response to Epstein-Barr virus infected cells (A-C), with and increasing %functional NK cells and subsets (measures as expressing CD107a, IFN-γ, or both) are observed with increasing tA01 motifs' copies (A'-C') Figure 2. KIR telomeric A motifs (tA01) titrate NK cells' functional response to Epstein-Barr virus infected cells (A-C), with and increasing %functional NK cells and subsets (measures as expressing CD107a, IFN-γ, or both) are observed with increasing tA01 motifs' copies (A'-C') Disclosures No relevant conflicts of interest to declare.

Sign in / Sign up

Export Citation Format

Share Document