scholarly journals Distinct Bioenergetic Features of Human Invariant Natural Killer T Cells Enable Retained Functions in Nutrient-Deprived States

2021 ◽  
Vol 12 ◽  
Author(s):  
Priya Khurana ◽  
Chakkapong Burudpakdee ◽  
Stephan A. Grupp ◽  
Ulf H. Beier ◽  
David M. Barrett ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
Metabolic Flux ◽  
Inkt Cell ◽  
Flux Analysis ◽  
Inkt Cells ◽  
Effector Functions ◽  
Functional Features ◽  
Invariant Natural Killer ◽  
Natural Killer T

Invariant natural killer T (iNKT) cells comprise a unique subset of lymphocytes that are primed for activation and possess innate NK-like functional features. Currently, iNKT cell-based immunotherapies remain in early clinical stages, and little is known about the ability of these cells to survive and retain effector functions within the solid tumor microenvironment (TME) long-term. In conventional T cells (TCONV), cellular metabolism is linked to effector functions and their ability to adapt to the nutrient-poor TME. In contrast, the bioenergetic requirements of iNKT cells – particularly those of human iNKT cells – at baseline and upon stimulation are not well understood; neither is how these requirements affect effector functions such as production of cytokines and cytolytic proteins. We find that unlike TCONV, human iNKT cells are not dependent upon glucose or glutamine for these effector functions upon stimulation with anti-CD3 and anti-CD28. Additionally, transcriptional profiling revealed that stimulated human iNKT cells are less glycolytic than TCONV and display higher expression of fatty acid oxidation (FAO) and adenosine monophosphate-activated protein kinase (AMPK) pathway genes. Furthermore, stimulated iNKT cells displayed higher mitochondrial mass and membrane potential relative to TCONV. Real-time Seahorse metabolic flux analysis revealed that stimulated human iNKT cells utilize fatty acids as substrates for oxidation more than stimulated TCONV. Together, our data suggest that human iNKT cells possess different bioenergetic requirements from TCONV and display a more oxidative metabolic program relative to effector TCONV. Importantly, iNKT cell-based immunotherapeutic strategies could co-opt such unique features of iNKT cells to improve their efficacy and longevity of anti-tumor responses.

scholarly journals Distinct bioenergetic features of human invariant natural killer T (iNKT) cells enable retained functions in nutrient-deprived states

2021 ◽  
Author(s):  
Priya Khurana ◽  
Chakkapong Burudpakdee ◽  
Stephan A. Grupp ◽  
Ulf H. Beier ◽  
David M. Barrett ◽  
...  
Keyword(s):  
Natural Killer ◽  
Metabolic Flux ◽  
Cytokine Production ◽  
Inkt Cell ◽  
Flux Analysis ◽  
Inkt Cells ◽  
Effector Functions ◽  
Functional Features ◽  
Invariant Natural Killer ◽  
Natural Killer T

ABSTRACTInvariant natural killer T (iNKT) cells comprise a unique subset of lymphocytes that are primed for activation and possess innate NK-like functional features. Currently, iNKT cell-based immunotherapies remain in early clinical stages, and little is known about the ability of these cells to survive and retain effector functions within the solid tumor microenvironment (TME) long-term. In conventional T cells (TCONV), cellular metabolism is linked to effector functions and their ability to adapt to the nutrient-poor TME. In contrast, the bioenergetic requirements of iNKT cells – particularly those of human iNKT cells – at baseline and upon stimulation are not well understood; neither is how these requirements affect cytokine production or anti-tumor effector functions. We find that unlike TCONV, human iNKT cells are not dependent upon glucose or glutamine for cytokine production and cytotoxicity upon stimulation with anti-CD3 and anti-CD28. Additionally, transcriptional profiling revealed that stimulated human iNKT cells are less glycolytic than TCONV and display higher expression of fatty acid oxidation (FAO) and adenosine monophosphate-activated protein kinase (AMPK) pathway genes. Furthermore, stimulated iNKT cells displayed higher mitochondrial mass and membrane potential relative to TCONV. Real-time Seahorse metabolic flux analysis revealed that stimulated human iNKT cells utilize fatty acids as substrates for oxidation more than stimulated TCONV. Together, our data suggest that human iNKT cells possess different bioenergetic requirements from TCONV and display a more memory-like metabolic program relative to effector TCONV. Importantly, iNKT cell-based immunotherapeutic strategies could co-opt such unique features of iNKT cells to improve their efficacy and longevity of anti-tumor responses.

scholarly journals Nur77 controls tolerance induction, terminal differentiation, and effector functions in semi-invariant natural killer T cells

2020 ◽  
Vol 117 (29) ◽  
pp. 17156-17165 ◽  
Author(s):  
Amrendra Kumar ◽  
Timothy M. Hill ◽  
Laura E. Gordy ◽  
Naveenchandra Suryadevara ◽  
Lan Wu ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
Cell Subset ◽  
Terminal Differentiation ◽  
Tolerance Induction ◽  
Cell Development ◽  
Inkt Cell ◽  
Inkt Cells ◽  
Effector Functions ◽  
Invariant Natural Killer

Semi-invariant natural killer T (iNKT) cells are self-reactive lymphocytes, yet how this lineage attains self-tolerance remains unknown. iNKT cells constitutively express high levels ofNr4a1-encoded Nur77, a transcription factor that integrates signal strength downstream of the T cell receptor (TCR) within activated thymocytes and peripheral T cells. The function of Nur77 in iNKT cells is unknown. Here we report that sustained Nur77 overexpression (Nur77tg) in mouse thymocytes abrogates iNKT cell development. Introgression of a rearrangedVα14-Jα18TCR-α chain gene into the Nur77tg(Nur77tg;Vα14tg) mouse rescued iNKT cell development up to the early precursor stage, stage 0. iNKT cells in bone marrow chimeras that reconstituted thymic cellularity developed beyond stage 0 precursors and yielded IL-4–producing NKT2 cell subset but not IFN-γ–producing NKT1 cell subset. Nonetheless, the developing thymic iNKT cells that emerged in these chimeras expressed the exhaustion marker PD1 and responded poorly to a strong glycolipid agonist. Thus, Nur77 integrates signals emanating from the TCR to control thymic iNKT cell tolerance induction, terminal differentiation, and effector functions.

scholarly journals Longitudinal analysis of invariant natural killer T cell activation reveals a cMAF-associated transcriptional state of NKT10 cells

2021 ◽  
Author(s):  
Lydia Lynch ◽  
Harry Kane ◽  
Nelson M LaMarche ◽  
Áine Ní Scannail ◽  
Michael P. Brenner
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
T Cell Activation ◽  
Cell Activation ◽  
Inkt Cell ◽  
Inkt Cells ◽  
Innate T Cells ◽  
Nonpeptide Antigens ◽  
Invariant Natural Killer ◽  
Natural Killer T

Innate T cells, including CD1d-restricted invariant natural killer T (iNKT) cells, are characterized by their rapid activation in response to nonpeptide antigens, such as lipids. While the transcriptional profiles of naive, effector and memory adaptive T cells have been well studied, less is known about transcriptional regulation of different iNKT cell activation states. Here, using single cell RNA-sequencing, we performed longitudinal profiling of activated iNKT cells, generating a transcriptomic atlas of iNKT cell activation states. We found that transcriptional signatures of activation are highly conserved among heterogeneous iNKT cell populations, including NKT1, NKT2 and NKT17 subsets, and human iNKT cells. Strikingly, we found that regulatory iNKT cells, such as adipose iNKT cells, undergo blunted activation, and display constitutive enrichment of memory-like cMAF+ and KLRG1+ populations. Moreover, we identify a conserved cMAF-associated transcriptional network among NKT10 cells, providing novel insights into the biology of regulatory and antigen experienced iNKT cells.

scholarly journals Innate and cytokine-driven signals, rather than microbial antigens, dominate in natural killer T cell activation during microbial infection

2011 ◽  
Vol 208 (6) ◽  
pp. 1163-1177 ◽  
Author(s):  
Manfred Brigl ◽  
Raju V.V. Tatituri ◽  
Gerald F.M. Watts ◽  
Veemal Bhowruth ◽  
Elizabeth A. Leadbetter ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
T Cell Activation ◽  
Cell Activation ◽  
Constitutive Expression ◽  
Microbial Pathogens ◽  
Inkt Cell ◽  
Microbial Infection ◽  
Inkt Cells ◽  
Natural Killer T

Invariant natural killer T cells (iNKT cells) are critical for host defense against a variety of microbial pathogens. However, the central question of how iNKT cells are activated by microbes has not been fully explained. The example of adaptive MHC-restricted T cells, studies using synthetic pharmacological α-galactosylceramides, and the recent discovery of microbial iNKT cell ligands have all suggested that recognition of foreign lipid antigens is the main driver for iNKT cell activation during infection. However, when we compared the role of microbial antigens versus innate cytokine-driven mechanisms, we found that iNKT cell interferon-γ production after in vitro stimulation or infection with diverse bacteria overwhelmingly depended on toll-like receptor–driven IL-12. Importantly, activation of iNKT cells in vivo during infection with Sphingomonas yanoikuyae or Streptococcus pneumoniae, pathogens which are known to express iNKT cell antigens and which require iNKT cells for effective protection, also predominantly depended on IL-12. Constitutive expression of high levels of IL-12 receptor by iNKT cells enabled instant IL-12–induced STAT4 activation, demonstrating that among T cells, iNKT cells are uniquely equipped for immediate, cytokine-driven activation. These findings reveal that innate and cytokine-driven signals, rather than cognate microbial antigen, dominate in iNKT cell activation during microbial infections.

Relevance of sexual dimorphism to regulatory T cells: estradiol promotes IFN-γ production by invariant natural killer T cells

Blood ◽  
2005 ◽  
Vol 105 (6) ◽  
pp. 2415-2420 ◽  
Author(s):  
Pierre Gourdy ◽  
Luiza M. Araujo ◽  
Ren Zhu ◽  
Barbara Garmy-Susini ◽  
Séverine Diem ◽  
...  
Keyword(s):  
T Cells ◽  
Natural Killer ◽  
Interleukin 4 ◽  
Response To Treatment ◽  
Inkt Cells ◽  
Gender Dimorphism ◽  
Ifn Γ ◽  
Invariant Natural Killer ◽  
Natural Killer T

Abstract Mechanisms accounting for gender dimorphism during immune responses are still poorly understood. Since invariant natural killer T (iNKT) cells exert important regulatory functions through their capacity to produce both T helper 1 (Th1) and Th2 cytokines, we addressed the question of whether these activities could be modulated by sexual hormones. We found that in vivo challenge with the specific ligand of iNKT cells, α-galactosylceramide (α-GalCer), induced significantly higher concentrations of interferon γ (IFN-γ) in the serum of female than in that of male mice, while interleukin 4 (IL-4) production was not modified. In support of a crucial role of ovarian hormones in this phenomenon, a significant decrease of serum IFN-γ concentrations occurred in ovariectomized females, in response to treatment with α-GalCer, while orchidectomy affected neither IFN-γ nor IL-4 serum concentrations in males. The implication of estrogens in this selective enhancement of IFN-γ production by iNKT cells was demonstrated by (1) the increased α-GalCer–induced IFN-γ synthesis by iNKT cells upon both in vitro and in vivo exposure to estradiol and (2) the abolition of the sex-linked difference in α-GalCer–induced IFN-γ release in estrogen receptor α-deficient mice. These results provide the first evidence that estrogens influence iNKT cells leading to this gender dimorphism in their cytokine production profile.

scholarly journals Vaccine Based on Dendritic Cells Electroporated with an Exogenous Ovalbumin Protein and Pulsed with Invariant Natural Killer T Cell Ligands Effectively Induces Antigen-Specific Antitumor Immunity

Cancers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 171
Author(s):  
Akihiro Watanabe ◽  
Kimihiro Yamashita ◽  
Mitsugu Fujita ◽  
Akira Arimoto ◽  
Masayasu Nishi ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Natural Killer ◽  
Cd8 T Cells ◽  
Antitumor Immunity ◽  
Tumor Antigens ◽  
Vaccine Strategy ◽  
Inkt Cells ◽  
Invariant Natural Killer ◽  
Natural Killer T

(1) Background: Cancer vaccines are administered to induce cytotoxic CD8+ T cells (CTLs) specific for tumor antigens. Invariant natural killer T (iNKT) cells, the specific T cells activated by α-galactosylceramide (α-GalCer), play important roles in this process as they are involved in both innate and adaptive immunity. We developed a new cancer vaccine strategy in which dendritic cells (DCs) were loaded with an exogenous ovalbumin (OVA) protein by electroporation (EP) and pulsed with α-GalCer. (2) Methods: We generated bone marrow-derived DCs from C57BL/6 mice, loaded full-length ovalbumin proteins to the DCs by EP, and pulsed them with α-GalCer (OVA-EP-galDCs). The OVA-EP-galDCs were intravenously administered to C57BL/6 mice as a vaccine. We then investigated subsequent immune responses, such as the induction of iNKT cells, NK cells, intrinsic DCs, and OVA-specific CD8+ T cells, including tissue-resident memory T (TRM) cells. (3) Results: The OVA-EP-galDC vaccine efficiently rejected subcutaneous tumors in a manner primarily dependent on CD8+ T cells. In addition to the OVA-specific CD8+ T cells both in early and late phases, we observed the induction of antigen-specific TRM cells in the skin. (4) Conclusions: The OVA-EP-galDC vaccine efficiently induced antigen-specific antitumor immunity, which was sustained over time, as shown by the TRM cells.

Abstract 541: Specific Deletion of LDL Receptor--Related Protein on Macrophages Skews Cytokine Production by Invariant Natural Killer T Cells

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Roman Covarrubias ◽  
Amy S Major
Keyword(s):  
Natural Killer ◽  
Cell Activation ◽  
Ldl Receptor ◽  
Inkt Cell ◽  
Related Protein ◽  
Inkt Cells ◽  
Glycolipid Antigen ◽  
Invariant Natural Killer ◽  
Natural Killer T

Invariant Natural Killer T (iNKT) cells are specialized lymphocytes that when activated can regulate chronic inflammatory conditions and atherosclerotic processes. The activation of iNKT cells occurs when glycolipid antigens bind the MHC class-I like molecule CD1d present on antigen presenting cells (APCs). The pathways by which glycolipid antigens target CD1d for presentation and activation of iNKT cells remain unclear, yet the expression of surface receptors associated with lipid homeostasis, such as the LDL receptor (LDLr), have been implicated in the modulation of iNKT cell activation. The LDLr has been shown to modulate this process by binding apoE-containing lipoproteins, which can carry antigenic glycolipids for iNKT cell activation. The LDL receptor-related protein (LRP), a transmembrane receptor from the LDL receptor family of proteins, shares structural homology with LDLr and can bind a number of ligands including apoE-containing lipoproteins. We hypothesized that LRP can play an active role in glycolipid antigen presentation and subsequent activation of iNKT cells. Here, we demonstrate that LRP is preferentially expressed at high levels on F4/80 + macrophages, when compared to other APCs. We also show that a specialized subset of macrophages expressing CD169, known for their ability to present glycolipid antigen to iNKT cells, have increased levels of LRP when compared to CD169 - macrophages. Using mice with a targeted deletion of LRP in macrophages, we observed decreased activation of iNKT cells in vitro (24, 48 hours) and normal IFN-gamma but blunted IL-4 response in vivo. Further flow cytometric analysis showed normal surface expression of CD1d in LRP-cKO macrophages as well as normal uptake of fluorescently labeled glycolipid in vitro . Additionally, analysis of the iNKT cell compartment in LRP-cKO mice revealed intact numbers and percentages of iNKT cells and no homeostatic disruption as evidenced by absence of programmed death-1 and LY-49. Collectively, these data suggest that macrophage LRP contributes to early iNKT cell activation by enhancing early IL-4 responses.

scholarly journals TNF receptor associated factor 3 plays a key role in development and function of invariant natural killer T cells

2013 ◽  
Vol 210 (6) ◽  
pp. 1079-1086 ◽  
Author(s):  
Zuoan Yi ◽  
Laura L. Stunz ◽  
Gail A. Bishop
Keyword(s):  
Natural Killer ◽  
Developmental Stages ◽  
Critical Role ◽  
Inkt Cell ◽  
Tnf Receptor ◽  
Inkt Cells ◽  
Tcr Signaling ◽  
Associated Factor ◽  
Invariant Natural Killer ◽  
Natural Killer T

TCR signaling is a prerequisite for early stage development of invariant natural killer T (iNKT) cells, whereas IL-15 signaling is required for expansion and maturation at later stages. In this study, we show that TNF receptor associated factor 3 (TRAF3) plays a critical role in the transition between these two distinct signaling pathways and developmental stages. TRAF3-deficient iNKT cells in CD4CreTRAF3flox/flox (T-TRAF3−/−) mice exhibit defective up-regulation of T-bet and CD122, two critical molecules for IL-15 signaling, and as a consequence, IL-15–mediated iNKT cell proliferation and survival are impaired. Consistently, development of iNKT cells in T-TRAF3−/− mice shows a major defect at developmental stages 2 and 3, but not stages 0 and 1. We further demonstrated that defective T-bet up-regulation occurring during the stage 1 to stage 2 transition results from reduced TCR signaling in TRAF3−/− iNKT cells. In addition, mature TRAF3−/− iNKT cells displayed defective cytokine responses upon TCR stimulation. Collectively, our results reveal that by modulating the relative strength of TCR signaling, TRAF3 is an important regulator of iNKT cell development and functions.

scholarly journals Invariant Natural Killer T-cell Dynamics in Human Immunodeficiency Virus–associated Tuberculosis

2019 ◽  
Vol 70 (9) ◽  
pp. 1865-1874 ◽  
Author(s):  
Naomi F Walker ◽  
Charles Opondo ◽  
Graeme Meintjes ◽  
Nishtha Jhilmeet ◽  
Jon S Friedland ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Antiretroviral Therapy ◽  
Natural Killer ◽  
Inkt Cell ◽  
Inkt Cells ◽  
Cross Sectional ◽  
Immunodeficiency Virus ◽  
Invariant Natural Killer ◽  
Hiv 1 ◽  
Natural Killer T

Abstract Background Tuberculosis (TB) is the leading cause of mortality and morbidity in people living with human immunodeficiency virus (HIV) infection (PLWH). PLWH with TB disease are at risk of the paradoxical TB-associated immune reconstitution inflammatory syndrome (TB-IRIS) when they commence antiretroviral therapy. However, the pathophysiology is incompletely understood and specific therapy is lacking. We investigated the hypothesis that invariant natural killer T (iNKT) cells contribute to innate immune dysfunction associated with TB-IRIS. Methods In a cross-sectional study of 101 PLWH and HIV-uninfected South African patients with active TB and controls, iNKT cells were enumerated using α-galactosylceramide-loaded CD1d tetramers and subsequently functionally characterized by flow cytometry. In a second study of 49 people with HIV type 1 (HIV-1) and active TB commencing antiretroviral therapy, iNKT cells in TB-IRIS patients and non-IRIS controls were compared longitudinally. Results Circulating iNKT cells were reduced in HIV-1 infection, most significantly the CD4+ subset, which was inversely associated with HIV-1 viral load. iNKT cells in HIV-associated TB had increased surface CD107a expression, indicating cytotoxic degranulation. Relatively increased iNKT cell frequency in patients with HIV-1 infection and active TB was associated with development of TB-IRIS following antiretroviral therapy initiation. iNKT cells in TB-IRIS were CD4+CD8– subset depleted and degranulated around the time of TB-IRIS onset. Conclusions Reduced iNKT cell CD4+ subsets as a result of HIV-1 infection may skew iNKT cell functionality toward cytotoxicity. Increased CD4– cytotoxic iNKT cells may contribute to immunopathology in TB-IRIS.

Sign in / Sign up

Export Citation Format

Share Document