SLP-76 Is Required for Optimal Natural Killer Cell Activation and Ly49 Receptor Acquisition

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 103-103
Author(s):  
Rebecca May ◽  
Taku Kambayashi
Keyword(s):  
T Cells ◽  
Plasma Membrane ◽  
Nk Cells ◽  
Signaling Pathways ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Granule Exocytosis ◽  
Activating Receptors ◽  
Mild Defect

Abstract Abstract 103 Natural killer (NK) cells are innate immune cells that defend the host from intracellular pathogens and tumors. Regulation of NK cell activation involves the expression of activating receptors that are finely counterbalanced by inhibitory MHC class I-binding receptors (e.g., Ly49 family members), which allow NK cells to achieve self-tolerance. How the precise signaling pathways leading from activating receptors contribute to effector function and inhibitory receptor acquisition by NK cells are not well understood. Thus, we aimed to dissect the proximal signaling pathways downstream of the Ly49D activating receptor and focused our studies on SLP-76 (SH2 containing leukocyte protein of 76kD), an adaptor molecule which is important in mediating signals downstream of ITAM-containing activating receptors in a variety of hematopoietic cell types. When NK cells were activated through Ly49D, SLP-76 was phosphorylated and recruited to the plasma membrane. SLP-76 was required for optimal signal transduction through Ly49D as SLP-76 knockout (KO) NK cells exhibited diminished ERK (extracellular signal-regulated kinase) and Akt phosphorylation compared to wildtype (WT) NK cells. These biochemical defects correlated with decreased IFNγ and TNFα production, and granule exocytosis by SLP-76 KO NK cells compared to WT NK cells. Although NK cells from SLP-76 KO mice appeared developmentally mature based on expression of late maturation markers DX5 and CD11b, we noted a selective defect in the acquisition of Ly49 family member inhibitory and activating receptors in SLP-76 KO NK cells. Since the defective function of SLP-76 KO NK cells might be related to their perturbed development, SLP-76 was inducibly deleted in NK cells after full maturation. Such NK cells displayed normal Ly49 receptor expression but still exhibited defective IFNg production and granule exocytosis, suggesting that SLP-76 plays an important role in Ly49D-mediated NK cell function. We next explored the mechanisms by which SLP-76 relocalizes from the cytosol to the plasma membrane and is subsequently phosphorylated. As this process depends on membrane-resident LAT (linker of activation of T cells) family adaptor molecules (LAT1 and LAT2) in T cells and mast cells, we tested whether LAT1 and LAT2 were similarly crucial for SLP-76 function in NK cells. Like SLP-76 KO NK cells, LAT1/LAT2 double KO (DKO) NK cells displayed significant functional defects. Surprisingly, however, membrane recruitment and phosphorylation of SLP-76 were intact in LAT1/LAT2 DKO NK cells following Ly49D stimulation. Moreover, a SLP-76 mutant that is unable to bind to LAT1/LAT2 was also recruited to the plasma membrane following Ly49D stimulation. Together, these results point towards the existence of a novel alternative signaling pathway leading to SLP-76 activation in NK cells. This alternative pathway may be important during NK cell development, since LAT1/LAT2 DKO NK cells displayed only a mild defect in Ly49 receptor acquisition compared to SLP-76 KO NK cells, underscoring the significance of this LAT1/LAT2-independent pathway. Together, these results demonstrate a critical role for a LAT1/LAT2-dependent and independent pathway leading to SLP-76 in NK cell activation and development. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Multiplicity and plasticity of natural killer cell signaling pathways

Blood ◽  
2006 ◽  
Vol 107 (6) ◽  
pp. 2364-2372 ◽  
Author(s):  
Sabrina Chiesa ◽  
Michael Mingueneau ◽  
Nicolas Fuseri ◽  
Bernard Malissen ◽  
David H. Raulet ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
T Cell Activation ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Interferon Γ ◽  
Effector Functions ◽  
Activating Receptors ◽  
Cell Effector

AbstractNatural killer (NK) cells express an array of activating receptors that associate with DAP12 (KARAP), CD3ζ, and/or FcRγ ITAM (immunoreceptor tyrosine-based activation motif)–bearing signaling subunits. In T and mast cells, ITAM-dependent signals are integrated by critical scaffolding elements such as LAT (linker for activation of T cells) and NTAL (non–T-cell activation linker). Using mice that are deficient for ITAM-bearing molecules, LAT or NTAL, we show that NK cell cytotoxicity and interferon-γ secretion are initiated by ITAM-dependent and -independent as well as LAT/NTAL-dependent and -independent pathways. The role of these various signaling circuits depends on the target cell as well as on the activation status of the NK cell. The multiplicity and the plasticity of the pathways that initiate NK cell effector functions contrast with the situation in T cells and B cells and provide an explanation for the resiliency of NK cell effector functions to various pharmacologic inhibitors and genetic mutations in signaling molecules.

scholarly journals T cell regulation of natural killer cells

2013 ◽  
Vol 210 (6) ◽  
pp. 1065-1068 ◽  
Author(s):  
Yann Kerdiles ◽  
Sophie Ugolini ◽  
Eric Vivier
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Activity ◽  
Adaptive Immune System ◽  
Nk Cell Activity ◽  
Promising Target

In light of their role in the immune response against tumors and viruses, natural killer (NK) cells represent a promising target for immunotherapy. Before this target is reached, the various mechanisms that control NK cell activity must first be identified and understood. In the past decades, studies have identified two critical processes that prevent spontaneous NK cell–mediated autoimmune activation while maximizing the efficiency of these cells during an immune response. First is the education process, whereby NK cells adapt to their environment by sensing ligands for inhibitory and activating receptors. Second is the priming phase of NK cell activation, which arms NK cells with appropriate cytotoxic molecules during inflammation. New studies now indicate that NK cell proliferation, accumulation, and activation are also under the control of regulatory T cells that restrict availability of IL-2 released by activated CD4+ T cells. Together with other recent studies, these data highlight the importance of the adaptive immune system in the regulation of NK cell activity.

scholarly journals Human T-Cell Leukemia Virus Type 1 (HTLV-1) p12I Down-Modulates ICAM-1 and -2 and Reduces Adherence of Natural Killer Cells, Thereby Protecting HTLV-1-Infected Primary CD4+ T Cells from Autologous Natural Killer Cell-Mediated Cytotoxicity despite the Reduction of Major Histocompatibility Complex Class I Molecules on Infected Cells

2007 ◽  
Vol 81 (18) ◽  
pp. 9707-9717 ◽  
Author(s):  
Prabal Banerjee ◽  
Gerold Feuer ◽  
Edward Barker
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Leukemia Virus ◽  
Cell Leukemia Virus Type ◽  
Human T Cell ◽  
Activating Receptors ◽  
T Cell Leukemia Virus ◽  
Infected Cells

ABSTRACT Although natural killer (NK) cell-mediated control of viral infections is well documented, very little is known about the ability of NK cells to restrain human T-cell leukemia virus type 1 (HTLV-1) infection. In the current study we show that NK cells are unable to kill HTLV-1-infected primary CD4+ T cells. Exposure of NK cells to interleukin-2 (IL-2) resulted in only a marginal increase in their ability to kill HTLV-1-infected primary CD4+ T cells. This inability of NK cells to kill HTLV-1-infected CD4+ T cells occurred despite the down-modulation of major histocompatibility complex (MHC) class I molecules, one of the ligands for the major NK cell inhibitory receptor, by HTLV-1 p12I on CD4+ T cells. One reason for this diminished ability of NK cells to kill HTLV-1-infected cells was the decreased ability of NK cells to adhere to HTLV-1-infected cells because of HTLV-1 p12I-mediated down-modulation of intercellular adhesion molecule 1 (ICAM-1) and ICAM-2. We also found that HTLV-1-infected CD4+ T cells did not express ligands for NK cell activating receptors, NCR and NKG2D, although they did express ligands for NK cell coactivating receptors, NTB-A and 2B4. Thus, despite HTLV-1-mediated down-modulation of MHC-I molecules, HTLV-1-infected primary CD4+ T cells avoids NK cell destruction by modulating ICAM expression and shunning the expression of ligands for activating receptors.

scholarly journals Association with FcRγ Is Essential for Activation Signal through NKR-P1 (CD161) in Natural Killer (NK) Cells and NK1.1+ T Cells

1997 ◽  
Vol 186 (12) ◽  
pp. 1957-1963 ◽  
Author(s):  
Noriko Arase ◽  
Hisashi Arase ◽  
Seung Yong Park ◽  
Hiroshi Ohno ◽  
Chisei Ra ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Cell Activation ◽  
Nk Cell ◽  
Cross Linking ◽  
Primary Host ◽  
Receptor Complexes ◽  
Ifn Γ ◽  
Deficient Mice

Natural killer (NK) cells exhibit cytotoxicity against variety of tumor cells and virus-infected cells without prior sensitization and represent unique lymphocytes involved in primary host defense. NKR-P1 is thought to be one of NK receptors mediating activation signals because cross-linking of NKR-P1 activates NK cells to exhibit cytotoxicity and IFN-γ production. However, molecular mechanism of NK cell activation via NKR-P1 is not well elucidated. In this study, we analyzed the cell surface complex associated with NKR-P1 on NK cells and found that NKR-P1 associates with the FcRγ chain which is an essential component of Fc receptors for IgG and IgE. The association between FcRγ and NKR-P1 is independent of Fc receptor complexes. Furthermore, NK cells from FcRγ-deficient mice did not show cytotoxicity or IFN-γ production upon NKR-P1 cross-linking. Similarly, NK1.1+ T cells from FcRγ-deficient mice did not produce IFN-γ upon NKR-P1 crosslinking. These findings demonstrate that the FcRγ chain plays an important role in activation of NK cells via the NKR-P1 molecule.

scholarly journals miR-1224 contributes to ischemic stroke-mediated natural killer cell dysfunction by targeting Sp1 signaling

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Yan Feng ◽  
Yan Li ◽  
Ying Zhang ◽  
Bo-Hao Zhang ◽  
Hui Zhao ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Nk Cells ◽  
Natural Killer ◽  
Brain Ischemia ◽  
Cell Activation ◽  
Nk Cell ◽  
Cell Activity ◽  
Passive Transfer ◽  
Immune Defense ◽  
Nk Cell Activity

Abstract Background Brain ischemia compromises natural killer (NK) cell-mediated immune defenses by acting on neurogenic and intracellular pathways. Less is known about the posttranscriptional mechanisms that regulate NK cell activation and cytotoxicity after ischemic stroke. Methods Using a NanoString nCounter® miRNA array panel, we explored the microRNA (miRNA) profile of splenic NK cells in mice subjected to middle cerebral artery occlusion. Differential gene expression and function/pathway analysis were applied to investigate the main functions of predicted miRNA target genes. miR-1224 inhibitor/mimics transfection and passive transfer of NK cells were performed to confirm the impact of miR-1224 in NK cells after brain ischemia. Results We observed striking dysregulation of several miRNAs in response to ischemia. Among those miRNAs, miR-1224 markedly increased 3 days after ischemic stroke. Transfection of miR-1224 mimics into NK cells resulted in suppression of NK cell activity, while an miR-1224 inhibitor enhanced NK cell activity and cytotoxicity, especially in the periphery. Passive transfer of NK cells treated with an miR-1224 inhibitor prevented the accumulation of a bacterial burden in the lungs after ischemic stroke, suggesting an enhanced immune defense of NK cells. The transcription factor Sp1, which controls cytokine/chemokine release by NK cells at the transcriptional level, is a predicted target of miR-1224. The inhibitory effect of miR-1224 on NK cell activity was blocked in Sp1 knockout mice. Conclusions These findings indicate that miR-1224 may serve as a negative regulator of NK cell activation in an Sp1-dependent manner; this mechanism may be a novel target to prevent poststroke infection specifically in the periphery and preserve immune defense in the brain.

Abstract 26: IL-17 Causes Hypertension, Reduced Fetal Weight And Natural Killer Cell Activation In The Absence Of T Cells

Hypertension ◽  
2021 ◽  
Vol 78 (Suppl_1) ◽  
Author(s):  
Sarah J Fitzgerald ◽  
James Hogg ◽  
Evangeline Deer ◽  
Nathan Campbell ◽  
Owen Herrock ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
Rat Model ◽  
Cell Activation ◽  
Nk Cell ◽  
Killer Cell ◽  
Interleukin 17 ◽  
Sprague Dawley ◽  
Th Cells ◽  
Atp Production

Preeclampsia (PE) is characterized by new onset hypertension (HTN), intrauterine growth restriction (IUGR), multi-organ dysfunction, and is associated with increased inflammatory cytokines, such as interleukin 17 (IL-17). More recent studies demonstrate a role for mitochondrial (mt) dysfunction/mtROS in the pathogenesis of PE. Although we have shown T helper cells from a rat model of PE cause HTN and mt dysfunction the causative factors for mt dysfunction are still being identified. In addition, we have shown that IL-17 cause HTN, IUGR and activate natural killer (NK) cells, and cause mt dysfunction in pregnant Sprague Dawley rats. However, in our previous studies we couldn’t differentiate the effect of activated TH cells versus IL-17 to cause these characteristics of PE. The athymic nude rat model lacks mature T cells but does have other components of the immune system, and will thus allow us to examine the role of IL-17 in the absence of TH cells in the pathophysiology of PE. We hypothesize that in the absence of T cells IL-17 induces HTN, NK cell activation and IUGR which is associated with renal and placental mt dysfunction during pregnancy. To test our hypothesis, IL-17 (150 pg/day) was infused via osmotic minipumps inserted on gestation day (GD) 14. Blood pressure (MAP) and mt function were measured on GD19 and were compared to untreated pregnant (NP) athymic nude rats. In response to IL-17; MAP increased from 95±4mmHg in NP(n=6) to 115±2 in NP+IL-17(n=6) (p<0.001); pup weight decreased from 1.46±0.2 g in NP (n=6) to 0.98±0.07g in NP+IL-17 (n=6) (p<0.05); NK cell activation increased from 0±0 %lymphocytes in NP (n=3) to 0.4±0.1% lymphocytes in NP+IL-17 rats (n=6). Interestingly, placental mtROS reduced 54% fold compared to NP and renal mtROS reduced 51.2% compared to NP. ATP production increased from 15.53±1.6 pmol of O2/sec/mg in NP (n=3) to 105.5±91 pmol of O2/sec/mg in NP+IL-17 (n=3) in the placenta, and from 1196±460 pmol of O2/sec/mg in NP (n=4) to 2016±951 pmol of O2/sec/mg NP+IL17 (n=4) in the kidney. These results show that although IL-17 induces HTN, IUGR, and NK cell activation independent of T cells, T cells are necessary for reduced mitochondrial function observed in PE and in rat models of placental ischemia.

Differential requirement for the transcription factor PU.1 in the generation of natural killer cells versus B and T cells

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2625-2632 ◽  
Author(s):  
Francesco Colucci ◽  
Sandrine I. Samson ◽  
Rodney P. DeKoter ◽  
Olivier Lantz ◽  
Harinder Singh ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Nk Cell ◽  
Fetal Liver ◽  
Myeloid Cell ◽  
Cell Development ◽  
Stringent Requirement ◽  
Nk Cell Differentiation ◽  
Ets Family

Abstract PU.1 is a member of the Ets family of transcription factors required for the development of various lymphoid and myeloid cell lineages, but its role in natural killer (NK) cell development is not known. The study shows that PU.1 is expressed in NK cells and that, on cell transfer into alymphoid Rag2/γc−/−mice, hematopoietic progenitors of PU.1−/−fetal liver cells could generate functional NK cells but not B or T cells. Nevertheless, the numbers of bone marrow NK cell precursors and splenic mature NK cells were reduced compared to controls. Moreover,PU.1−/− NK cells displayed reduced expression of the receptors for stem cell factor and interleukin (IL)-7, suggesting a nonredundant role for PU.1 in regulating the expression of these cytokine receptor genes during NK cell development.PU.1−/− NK cells also showed defective expression of inhibitory and activating members of the Ly49 family and failed to proliferate in response to IL-2 and IL-12. Thus, despite the less stringent requirement for PU.1 in NK cell development compared to B and T cells, PU.1 regulates NK cell differentiation and homeostasis.

scholarly journals Prognostic significance of natural killer cell-associated markers in gastric cancer: quantitative analysis using multiplex immunohistochemistry

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Hee Young Na ◽  
Yujun Park ◽  
Soo Kyung Nam ◽  
Jiwon Koh ◽  
Yoonjin Kwak ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
T Cells ◽  
B Cells ◽  
Nk Cells ◽  
Natural Killer ◽  
Immune Cells ◽  
Nk Cell ◽  
Critical Role ◽  
Killer Cell ◽  
Prognostic Significance

Abstract Background Natural killer (NK) cells mediate the anti-tumoral immune response as an important component of innate immunity. The aim of this study was to investigate the prognostic significance and functional implication of NK cell-associated surface receptors in gastric cancer (GC) by using multiplex immunohistochemistry (mIHC). Methods We performed an mIHC on tissue microarray slides, including 55 GC tissue samples. A total of 11 antibodies including CD57, NKG2A, CD16, HLA-E, CD3, CD20, CD45, CD68, CK, SMA, and ki-67 were used. CD45 + CD3-CD57 + cells were considered as CD57 + NK cells. Results Among CD45 + immune cells, the proportion of CD57 + NK cell was the lowest (3.8%), whereas that of CD57 + and CD57- T cells (65.5%) was the highest, followed by macrophages (25.4%), and B cells (5.3%). CD57 + NK cells constituted 20% of CD45 + CD57 + immune cells while the remaining 80% were CD57 + T cells. The expression of HLA-E in tumor cells correlated with that in tumoral T cells, B cells, and macrophages, but not CD57 + NK cells. The higher density of tumoral CD57 + NK cells and tumoral CD57 + NKG2A + NK cells was associated with inferior survival. Conclusions Although the number of CD57 + NK cells was lower than that of other immune cells, CD57 + NK cells and CD57 + NKG2A + NK cells were significantly associated with poor outcomes, suggesting that NK cell subsets play a critical role in GC progression. NK cells and their inhibitory receptor, NKG2A, may be potential targets in GC.

scholarly journals 789 Generation of a Bicycle NK-TICA™, a novel NK cell engaging molecule to enhance targeted tumor cytotoxicity

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A824-A824
Author(s):  
Fay Dufort ◽  
Christopher Leitheiser ◽  
Gemma Mudd ◽  
Julia Kristensson ◽  
Alexandra Rezvaya ◽  
...  
Keyword(s):  
Phage Display ◽  
Nk Cells ◽  
Natural Killer ◽  
Tumor Antigen ◽  
Cell Activation ◽  
Immune Cell ◽  
Nk Cell ◽  
High Affinity ◽  
Tumor Cytotoxicity ◽  
Immune Oncology

BackgroundNatural killer (NK) cells are immune cells that can detect and eliminate tumor cells and bridge innate to adaptive immune responses. Tumor specific activation of NK cells is thus an area of active investigation in immune oncology, but to date has relied on complex biologic modalities (e.g., antibodies, fusion proteins, or cell therapies), each of which has inherent disadvantages in this application. Thus, alternative approaches are warranted. Bicycle® are small (ca. 1.5 kDa), chemically synthetic, structurally constrained peptides discovered via phage display and optimized using structure-driven design and medicinal chemistry approaches. We have now applied this technology to identify Bicycles that bind specifically to the key activating receptors, NKp46 and CD16a. When chemically coupled to tumor antigen binding Bicycles this results in highly potent, antigen-dependent receptor activation and NK cell activation. We term this new class of fully synthetic molecules Bicycle® natural killer- tumor-targeted immune cell agonists (NK-TICAs™) and we will describe their discovery and evaluation in this presentation.MethodsUsing our unique phage display screening platform, we have identified high affinity, selective binders to NKp46 and CD16a. By conjugating the Bicycle® NK cell-engaging binders to a model tumor antigen EphA2-binding Bicycle®, we have developed a bifunctional Bicycle NK-TICA™ molecule. In in vitro functional assays, we evaluated the ability of the Bicycle NK-TICAs™ to induce NK cell activation as well as cell-mediated cytotoxicity and cytokine production in NK-tumor co-culture assays.ResultsWe have developed a novel modular compound with high affinity and selectivity to NK cell receptors with specific tumor targeting capability. We demonstrate potent, selective binding of our Bicycles to receptor-expressing cells and the capability of the bifunctional molecule to induce NK cell function. With Bicycle's novel NK-TICA™ compound, we demonstrate engagement of NK cells, specific activation and function of NK cells, and enhanced EphA2-expressing tumor cytotoxicity, in a dose dependent manner.ConclusionsBicycle NK-TICAs™ are novel therapeutic agents capable of enhancing the landscape of immune oncology. We hypothesize that utilization of Bicycle NK-TICA™ as a multifunctional immune cell engager will promote modulation of NK cells, and infiltration and anti-tumor activity of NK cells in solid tumors. The data presented here provide initial proof of concept for application of the Bicycle technology to drive NK cell-mediated tumor immunity.

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