Modulation of T-bet and Eomes during Maturation of Peripheral Blood NK Cells Does Not Depend on Licensing/Educating KIR

OMIP-098: A 26 parameter, 24 color flow cytometry panel for human memory NK cell phenotyping

This 26-parameter flow cytometry panel has been developed and optimized to analyze NK cell phenotype, using cryopreserved peripheral blood mononuclear cells (PBMCs) from people living with and without human immunodeficiency virus (PLWH, PWOH). Our panel is designed for the analysis of several parameters of total NK cells and memory NK cell subsets including markers of maturation, activation, and proliferation, as well as activating and inhibitory receptors. Other tissues have not been tested (Table 1 ).

Lung Cancer Induces NK Cell Contractility and Cytotoxicity Through Transcription Factor Nuclear Localization

Actomyosin-mediated cellular contractility is highly conserved for mechanotransduction and signalling. While this phenomenon has been observed in adherent cell models, whether/how contractile forces regulate the function of suspension cells like natural killer (NK) cells during cancer surveillance, is unknown. Here, we demonstrated in coculture settings that the evolutionarily conserved NK cell transcription factor, Eomes, undergoes nuclear shuttling during lung cancer cell surveillance. Biophysical and biochemical analyses revealed mechanistic enhancement of NK cell actomyosin-mediated contractility, which is associated with nuclear flattening, thus enabling nuclear entry of Eomes associated with enhanced NK cytotoxicity. We found that NK cells responded to the presumed immunosuppressive TGFβ in the NK-lung cancer coculture medium to sustain its intracellular contractility through myosin light chain phosphorylation, thereby promoting Eomes nuclear localization. Therefore, our results demonstrate that lung cancer cells provoke NK cell contractility as an early phase activation mechanism and that Eomes is a plausible mechano-responsive protein for increased NK cytotoxicity. There is scope for strategic application of actomyosin-mediated contractility modulating drugs ex vivo, to reinvigorate NK cells prior to adoptive cancer immunotherapy in vivo (177 words).

CD56-negative NK cells with impaired effector function expand in CMV and EBV co-infected healthy donors with age

Natural killer cells lacking expression of CD56 (CD56^neg NK cells) have been described in chronic HIV and hepatitis C virus infection. Features and functions of CD56^neg NK cells in the context of latent infection with CMV and / or EBV with age are not known. In a cohort of healthy donors >60 years of age, we found that co-infection with CMV and EBV drives expansion of CD56^neg NK cells. Functionally, CD56^neg NK cells displayed reduced cytotoxic capacity and IFN-γ production, a feature that was enhanced with CMV / EBV co-infection. Further, the frequency of CD56^neg NK cells correlated with accumulation of end-stage-differentiated T cells and a reduced CD4 / CD8 T cell ratio, reflecting an immune risk profile. CD56^neg NK cells had a mature phenotype characterized by low CD57 and KIR expression and lacked characteristics of cell senescence. No changes in their activating NK cell receptor expression, and no upregulation of the negative co-stimulation receptors PD-1 or TIM-3 were observed. In all, our data identify expansion of dysfunctional CD56^neg NK cells in CMV⁺EBV⁺ elderly individuals suggesting that these cells may function as shape-shifters of cellular immunity and argue for a previously unrecognized role of EBV in mediating immune risk in the elderly.

True Detective: Unraveling Group 1 Innate Lymphocyte Heterogeneity

Innate lymphoid cells (ILCs) consist of a heterogeneous family of lymphocytes that regulate tissue homeostasis and can contribute to pathology in mice and humans. Mammalian group 1 ILCs are defined by the production of interferon (IFN)-γ and the functional dependence on the transcription factor T-bet. While recent studies demonstrate that group 1 ILCs consist of circulating mature natural killer (NK) cells and tissue-resident ILC1s, the functional, phenotypic, and developmental properties that distinguish these two cell lineages are often confusing and difficult to dissect. In this review, we critically evaluate the current knowledge of mammalian group 1 ILC heterogeneity and propose new inclusive nomenclature to clarify the roles of ILC1s and NK cells during homeostasis and disease.

CXCR6+ NK Cells in Human Fetal Liver and Spleen Possess Unique Phenotypic and Functional Capabilities

Tissue-resident Natural Killer (NK) cells vary in phenotype according to tissue origin, but are typically CD56^bright, CXCR6⁺, and CD69⁺. NK cells appear very early in fetal development, but little is known about when markers of tissue residency appear during gestation and whether the expression of these markers, most notably the chemokine receptor CXCR6, are associated with differences in functional capability. Using multi-parametric flow cytometry, we interrogated fetal liver and spleen NK cells for the expression of a multitude of extracellular markers associated with NK cell maturation, differentiation, and migration. We analyzed total NK cells from fetal liver and spleen and compared them to their adult liver and spleen counterparts, and peripheral blood (PB) NK. We found that fetal NK cells resemble each other and their adult counterparts more than PB NK. Maturity markers including CD16, CD57, and KIR are lower in fetal NK cells than PB, and markers associated with an immature phenotype are higher in fetal liver and spleen NK cells (NKG2A, CD94, and CD27). However, T-bet/EOMES transcription factor profiles are similar amongst fetal and adult liver and spleen NK cells (T-bet⁻/EOMES⁺) but differ from PB NK cells (T-bet⁺EOMES⁻). Further, donor-matched fetal liver and spleen NK cells share similar patterns of expression for most markers as a function of gestational age. We also performed functional studies including degranulation, cytotoxicity, and antibody-dependent cellular cytotoxicity (ADCC) assays. Fetal liver and spleen NK cells displayed limited cytotoxic effector function in chromium release assays but produced copious amounts of TNFα and IFNγ, and degranulated efficiently in response to stimulation with PMA/ionomycin. Further, CXCR6⁺ NK cells in fetal liver and spleen produce more cytokines and degranulate more robustly than their CXCR6⁻ counterparts, even though CXCR6⁺ NK cells in fetal liver and spleen possess an immature phenotype. Major differences between CXCR6⁻ and + NK cell subsets appear to occur later in development, as a distinct CXCR6⁺ NK cell phenotype is much more clearly defined in PB. In conclusion, fetal liver and spleen NK cells share similar phenotypes, resemble their adult counterparts, and already possess a distinct CXCR6⁺ NK cell population with discrete functional capabilities.

Expression profile analysis of long non-coding RNA in acute myeloid leukemia by microarray and bioinformatics

Long non-coding RNAs (lncRNAs) are transcripts longer than 200 nt that are involved in tumorigenesis and play a key role in cancer progression. To determine whether lncRNAs are involved in acute myeloid leukemia (AML), we analyzed the expression profile of lncRNAs and mRNAs in AML. Five pairs of AML patients and iron deficiency anemia (IDA) controls were screened by microarray. Through coexpression analysis, differently expressed transcripts were divided into modules, and lncRNAs were functionally annotated. We further analyzed the clinical significance of crucial lncRNAs from modules in public data. Finally, the expression of three lncRNAs, RP11-222K16.2, AC092580.4, and RP11-305O.6, were validated in newly diagnosed AML, AML relapse, and IDA patient groups by quantitative RT-PCR, which may be associated with AML patients' overall survival. Further analysis showed that RP11-222K16.2 might affect the differentiation of natural killer cells, and promote the immunized evasion of AML by regulating Eomesodermin expression. Analysis of this study revealed that dysregulated lncRNAs and mRNAs in AML vs IDA controls could affect the immune system and hematopoietic cell differentiation. The biological functions of those lncRNAs need to be further validated.

Monocyte/Macrophage: NK Cell Cooperation-Old Tools for New Functions

Monocyte/macrophage and natural killer (NK) cells are partners from a phylogenetic standpoint of innate immune system development and its evolutionary progressive interaction with adaptive immunity. The equally conservative ways of development and differentiation of both invertebrate hemocytes and vertebrate macrophages are reviewed. Evolutionary conserved molecules occurring in macrophage receptors and effectors have been inherited by vertebrates after their common ancestor with invertebrates. Cytolytic functions of mammalian NK cells, which are rooted in immune cells of invertebrates, although certain NK cell receptors (NKRs) are mammalian new events, are characterized. Broad heterogeneity of macrophage and NK cell phenotypes that depends on surrounding microenvironment conditions and expression profiles of specific receptors and activation mechanisms of both cell types are discussed. The particular tissue specificity of macrophages and NK cells, as well as their plasticity and mechanisms of their polarization to different functional subtypes have been underlined. The chapter summarized studies revealing the specific molecular mechanisms and regulation of NK cells and macrophages that enable their highly specific cross-cooperation. Attention is given to the evolving role of human monocyte/macrophage and NK cell interaction in pathogenesis of hypersensitivity reaction-based disorders, including autoimmunity, as well as in cancer surveillance and progression.

Effect of CMV and Aging on the Differential Expression of CD300a, CD161, T-bet, and Eomes on NK Cell Subsets

Natural killer (NK) cells are innate lymphoid cells involved in the defense against virus-infected cells and tumor cells. NK cell phenotype and function is affected with age and cytomegalovirus (CMV) latent infection. Aging affects the frequency and phenotype of NK cells, and CMV infection also contributes to these alterations. Thus, a reduction of CD56^bright NK cell subpopulation associated with age and an expansion of memory-like NK cells CD56^dimCD57⁺NKG2C⁺ probably related to CMV seropositivity have been described. NK cells express T-bet and Eomes transcription factors that are necessary for the development of NK cells. Here, we analyze the effect of age and CMV seropositivity on the expression of CD300a and CD161 inhibitory receptors, and T-bet and Eomes transcription factors in NK cell subsets defined by the expression of CD56 and CD57. CD300a is expressed by the majority of NK cells. CD56^bright NK cells express higher levels of CD300a than CD56^dim NK cells. An increase in the expression of CD300a was associated with age, whereas a decreased expression of CD161 in CD56^dim NK cells was associated with CMV seropositivity. In CD56^dim NK cells, an increased percentage of CD57⁺CD300a⁺ and a reduction in the percentage of CD161⁺CD300a⁺ cells were found to be associated with CMV seropositivity. Regarding T-bet and Eomes transcription factors, CMV seropositivity was associated with a decrease of T-bet^hi in CD56^dimCD57⁺ NK cells from young individuals, whereas Eomes expression was increased with CMV seropositivity in both CD56^bright and CD56^dimCD57^+/− (from middle age and young individuals, respectively) and was decreased with aging in all NK subsets from the three group of age. In conclusion, CMV infection and age induce significant changes in the expression of CD300a and CD161 in NK cell subsets defined by the expression of CD56 and CD57. T-bet and Eomes are differentially expressed on NK cell subsets, and their expression is affected by CMV latent infection and aging.