iNKT Cell Numbers Research Articles

Hyperlipidemia interferes with the behavior of variant NKT cells

Abstract Background NKT cells significantly influence atherosclerosis development. However, inconsistent findings on the function of the NKT cells and the invariant subset in atherosclerosis remains a challenge. Moreover, there is no clarity on the role and phenotype of the variant (vNKT) subset in atherosclerosis. Purpose To understand the role of the vNKT subsets in HFD-induced atherosclerosis. Methods We extracted the data for meta-analysis to understand the role of the whole NKT and iNKT cells in atherosclerosis. PRISMA guidelines were followed for the meta-analysis. In addition, C57BL/6 mice (WT) were fed with HFD for 20 weeks from 6-8 weeks of age. vNKTs were identified as CD3+NK1.1+CD1d-tetramer- within the CD3+NK1.1+ NKT cell population in both liver and spleen by flow cytometry. Intracellular cyotkines staining was performed. Statistical differences inthe means of two groups are calculated by two-tailed Student’s t-test with nonparametric Mann-Whitney tests. P-value<0.05 was considered significant. All data represented as mean±SEM. Results The NKT cell numbers increased significantly in the spleen, lymph nodes, blood, and liver in the HFD-fed mice fed from 1.5 to 24 weeks in Apoe-/-, Ldlr-/- in comparison to wild-type mice (SMD, 2.51 [95% CI, 1.42, 3.61]). Contrary to this, the iNKT cell numbers and the iNKT TCR gene expression levels, decreased significantly in the HFD-fed mice (SMD, -2.04 [95% CI, -3.34, -0.75]). The reduction in iNKT cell numbers is also supported by the clinical data from the AMI patients when compared to healthy controls [SMD = -1.81, 95% CI = -2.89, -0.74] (Figure 1). In HFD-fed C57BL/6 hyperlipidemic mice, significantly increased levels of total cholesterol (HFD vs Chow; 226.5±29.66 vs 118.5±10.56 mg/dL, n=4) and LDLc (44.56±11.96 vs 16.69±1.13 mg%, n=4) was observed. The number of vNKTs in the liver was significantly increased by 46% (HFD vs Chow 28.35±2.28 vs 19.41±1.36, n=6-7) (Figure 2A). However, the CD8+ vNKTs were significantly decreased by 68.6% in the liver (4.72±0.99 vs 15.06±0.96) and the CD4+ vNKTs decreased more than two times in the HFD-fed WT liver (7.39±0.76 vs 18.28±0.36) (Figure 2B). Also, the intracellular IFN-γ+ vNKT cells doubled in their numbers in the HFD-fed spleen (14.31±1.39 vs 6.367±0.87) compared to the chow-fed mice (Figure 2C). Conclusion(s) Meta-analysis revealed dual nature of the NKT cells and its invariant subsets in atherosclerosis, since the whole NKTs increase whereas the iNKTs decrease in number. The vNKT subset actively participates in immune modulation in the HFD-induced hyperlipidemia by increasing their number, as well as by differentially regulating CD8 and CD4 co-receptors between chow and HFD. HFD induced a pro-inflammatory nature in the splenic vNKTs but not in liver vNKTs, that in turn may aggravate other immune cells. This data confirms the dual nature of the NKT subsets and reveals a crucial systemic involvement of vNKT cells in the progression of dyslipidemia.

Eed-dependent histone modification orchestrates the iNKT cell developmental program alleviating liver injury.

Polycomb repressive complex 2 (PRC2) is an evolutionarily conserved epigenetic modifier responsible for tri-methylation of lysine 27 on histone H3 (H3K27me3). Previous studies have linked PRC2 to invariant natural killer T (iNKT) cell development, but its physiological and precise role remained unclear. To address this, we conditionally deleted Eed, a core subunit of PRC2, in mouse T cells. The results showed that Eed-deficient mice exhibited a severe reduction in iNKT cell numbers, particularly NKT1 and NKT17 cells, while conventional T cells and NKT2 cells remained intact. Deletion of Eed disrupted iNKT cell differentiation, leading to increased cell death, which was accompanied by a severe reduction in H3K27me3 levels and abnormal expression of Zbtb16, Cdkn2a, and Cdkn1a. Interestingly, Eed-deficient mice were highly susceptible to acetaminophen-induced liver injury and inflammation in an iNKT cell-dependent manner, highlighting the critical role of Eed-mediated H3K27me3 marks in liver-resident iNKT cells. These findings provide further insight into the epigenetic orchestration of iNKT cell-specific transcriptional programs.

Traversing the bench to bedside journey for iNKT cell therapies.

Invariant natural killer T (iNKT) cells are immune cells that harness properties of both the innate and adaptive immune system and exert multiple functions critical for the control of various diseases. Prevention of graft-versus-host disease (GVHD) by iNKT cells has been demonstrated in mouse models and in correlative human studies in which high iNKT cell content in the donor graft is associated with reduced GVHD in the setting of allogeneic hematopoietic stem cell transplants. This suggests that approaches to increase the number of iNKT cells in the setting of an allogeneic transplant may reduce GVHD. iNKT cells can also induce cytolysis of tumor cells, and murine experiments demonstrate that activating iNKT cells in vivo or treating mice with ex vivo expanded iNKT cells can reduce tumor burden. More recently, research has focused on testing anti-tumor efficacy of iNKT cells genetically modified to express a chimeric antigen receptor (CAR) protein (CAR-iNKT) cells to enhance iNKT cell tumor killing. Further, several of these approaches are now being tested in clinical trials, with strong safety signals demonstrated, though efficacy remains to be established following these early phase clinical trials. Here we review the progress in the field relating to role of iNKT cells in GVHD prevention and anti- cancer efficacy. Although the iNKT field is progressing at an exciting rate, there is much to learn regarding iNKT cell subset immunophenotype and functional relationships, optimal ex vivo expansion approaches, ideal treatment protocols, need for cytokine support, and rejection risk of iNKT cells in the allogeneic setting.

Kidins220 and Aiolos promote thymic iNKT cell development by reducing TCR signals.

Development of T cells is controlled by the signal strength of the TCR. The scaffold protein kinase D-interacting substrate of 220 kilodalton (Kidins220) binds to the TCR; however, its role in T cell development was unknown. Here, we show that T cell-specific Kidins220 knockout (T-KO) mice have strongly reduced invariant natural killer T (iNKT) cell numbers and modest decreases in conventional T cells. Enhanced apoptosis due to increased TCR signaling in T-KO iNKT thymocytes of developmental stages 2 and 3 shows that Kidins220 down-regulates TCR signaling at these stages. scRNA-seq indicated that the transcription factor Aiolos is down-regulated in Kidins220-deficient iNKT cells. Analysis of an Aiolos KO demonstrated that Aiolos is a downstream effector of Kidins220 during iNKT cell development. In the periphery, T-KO iNKT cells show reduced TCR signaling upon stimulation with α-galactosylceramide, suggesting that Kidins220 promotes TCR signaling in peripheral iNKT cells. Thus, Kidins220 reduces or promotes signaling dependent on the iNKT cell developmental stage.

ACC1-mediated fatty acid biosynthesis intrinsically controls thymic iNKT cell development.

To meet the energetic requirements associated with activation, proliferation, and survival, T cells switch their metabolic signatures from energetically quiescent to activated. However, little is known about the role of metabolic pathway controlling the development of invariant natural killer T (iNKT) cells. In the present study, we found that acetyl-CoA carboxylase 1 (ACC1), a rate-limiting enzyme for the fatty acid biosynthesis pathway, plays an essential role in the development of iNKT cells in the thymus. Mice lacking T-cell specific ACC1 showed a reduced number of iNKT cells with an increased proportion of iNKT cells at immature stages 0 and 1. Furthermore, mixed bone marrow (BM) chimera experiments revealed that T-cell intrinsic ACC1 expression was selectively important for the development of thymic iNKT cells, especially for the differentiation of the NKT1 cell subset. Our single-cell RNA-sequencing (scRNA-seq) data and functional analysis demonstrated that ACC1 is responsible for survival of developing iNKT cells. Thus, these findings highlighted a novel role of ACC1 in controlling thymic iNKT cell development mediated by the control of cell survival.

Invariant natural killer T cells and incidence of first-time coronary events: a nested case-control study.

Invariant natural killer T (iNKT) cells, a T cell subset that is CD1d-restricted and expresses a semi-invariant T cell receptor, have been proposed to contribute to dyslipidaemia-driven cardiovascular disease due to their ability to specifically recognize lipid antigens. Studies in mice have attributed pro-atherogenic properties to iNKT cells, but studies in humans investigating associations of iNKT cells with incident coronary events (CE) are lacking. Here, we used flow cytometry to enumerate circulating iNKT cells (CD3+ CD1d-PBS57-Tetramer+) in a case-control cohort nested within the prospective population-based Malmö Diet and Cancer Study (n = 416) to explore associations with incident first-time CE during a median follow-up of 14 years. We found a significant inverse association between CD4- and CD8- double negative (DN) iNKT cells and incident CE, with an odds ratio of 0.62 [95% confidence interval (CI) 0.38-0.99; P = 0.046] comparing the highest vs. the lowest tertile of DN iNKT cells. The association remained significant after adjustment for cardiovascular risk factors with an odds ratio of 0.57 (95% CI 0.33-0.99; P = 0.046). In contrast, total iNKT cells were not significantly associated with incident CE after adjustment, with an odds ratio of 0.74 (95% CI 0.43-1.27; P = 0.276). Our findings indicate that animal studies suggesting an atherosclerosis-promoting role for iNKT cells may not translate to human cardiovascular disease as our data show an association between high circulating numbers of DN iNKT cells and decreased risk of incident CE.

Impaired thymic iNKT cell differentiation at early precursor stage in murine haploidentical bone marrow transplantation with GvHD.

Early recovery of donor-derived invariant natural killer T (iNKT) cells are associated with reduced risk of graft-versus-host disease (GvHD) and overall survival. Patients with severe GvHD, however, had much slower iNKT cell reconstitution relative to conventional T cells. To characterize the delay of iNKT cell reconstitution and explore its possible causes, we used a haploidentical bone marrow transplantation (haplo-BMT) mouse model with GvHD. We found the delayed recovery of thymic and peripheral iNKT cell numbers with markedly decreased thymic NKT1 subset in GvHD mice. The defective generation of thymic iNKT precursors with egress capability contributed to the reduced peripheral iNKT cells in GvHD mice. We further identified intermediate NK1.1- NKT1 precursor subpopulations under steady-state conditions and found that the differentiation of these subpopulations was impaired in the thymi of GvHD mice. Detailed characterization of iNKT precursors and thymic microenvironment showed a close association of elevated TCR/co-stimulatory signaling provided by double positive thymocytes and macrophages with defective down-regulation of proliferation, metabolism, and NKT2 signature in iNKT precursor cells. Correspondingly, NKT2 but not NKT1 differentiation was favored in GvHD mice. These data underline the important roles of TCR and co-stimulatory signaling in the differentiation of thymic iNKT subsets under transplantation conditions.

Involvement of iNKT Cells In Bronchial Asthma

Background: Bronchial asthma is a prevalent inflammatory disease characterized by infiltration with eosinophils, lymphocytes, and mast cells in the airway leading to airway hypersensitivity and increased mucus secretion. T helper (Th) 2-based immune responses drive the inflammatory process. Numerous mechanisms are being studied to understand the progression of allergen induce asthma which subsequently led to the identification of a new population of T cells called the iNKT cells which showed promising results when experimented on murine models. iNKT cells are potent immune modulators involved in a variety of immunoregulations. This potency is the result of their ability to produce prime Th2 cytokines. The recognition of lipid antigens is required for the activation of iNKT cells. When an inflammation occurs due to Th2 cells and ozone, endogenous glycolipids become modified. This causes the activation of various subsets of iNKT cells and initiates airway hyperactivity. Infrequent human studies depict that the number of iNKT cells in BAL fluid ranges from 1 % of lung lymphocytes to 14 % which is a sign of dynamic fluctuation in the number of iNKT cells.
 Methods: Selective literature review including primary and secondary sources of literature. Eg. Cochrane database, NCBI, MEDLINE database.

Epigenetic regulation of iNKT2 cell adoptive therapy on the imbalance of iNKT cell subsets in thymus of RA mice.

Epigenetic regulation affects the development and differentiation of iNKT cells. Our previous study found that the number of iNKT cells in thymus of RA mice was reduced and the ratio of subsets was unbalanced, but the related mechanism remains unclear. We adopted an adoptive infusion of iNKT2 cells with specific phenotypes and functions to RA mice and used the α-Galcer treatment group as control. The findings revealed that: 1. Adoptive treatment of iNKT cells decreased the proportion of iNKT1 and iNKT17 subsets in the thymus of RA mice, and increased the proportion of iNKT2 subsets. 2. Following treatment with iNKT cells, the expression of PLZF in thymus DP T cells was increased whereas the expression of T-bet in thymus iNKT cells was decreased in RA mice. 3. Adoptive therapy reduced the modification levels of H3Kb7me3 and H3K4me3 in the promoter regions of Zbtb16 (encoding PLZF) and Tbx21 (encoding T-bet) gene in thymus DP T cells and iNKT cells, and the reduction of H3K4me3 was particularly significant in the cell treatment group. Furthermore, adoptive therapy also upregulated the expression of UTX (histone demethylase) in thymus lymphocytes of RA mice. As a result, it is hypothesized that adoptive therapy of iNKT2 cells may affect the level of histone methylation in the promoter region of important transcription factor genes for iNKT development and differentiation, thereby directly or indirectly correcting the imbalance of iNKT subsets in the thymus of RA mice. These findings offer a fresh rationale and concept for the management of RA that targets.

Natural Killer T cells and the invariant subset promote atherosclerosis: A meta-analysis

AimsNatural Killer T (NKT) cells are reported to be both pro- and anti-atherosclerotic. With this meta-analysis, we evaluated the NKT population and their subsets in regulating the atherosclerotic disease in mice. Main methodsEighteen pre-clinical (mice, n = 1276) and 6 clinical observational studies (humans, n = 116) met the eligibility criteria for inclusion. Random effects model was used and standard mean difference (SMD) was calculated for the cell counts and aortic lesion area. Key findingsLesion area decreased in the absence of whole NKT cell population (−1.33[95%CI, −2.14, −0.52]), and in the absence of only iNKT subset (−0.66[95%CI, −1.69, 0.37]). However, lesion area increased after over-expression/activation of iNKTs (1.40[95%CI, 0.28, 2.52]). Atherogenic diet (AD) or high fat diet (HFD) increased the number of NKT cells (2.51[95%CI, 1.42, 3.61]), whereas the iNKT cell numbers and iNKT cell-specific gene expression decreased in mice (−2.04[95%CI, −3.34, −0.75]) and atherosclerotic patients (−1.81[95 % CI, −2.89, −0.74]). SignificanceHere we show that, NKT and iNKT cells promote atherosclerosis. In general, NKT cell population increases with the progression of the plaque in mice and the numbers of iNKT cells reduce once the disease is established both in mice and humans.

Profiling of innate and adaptive immune cells during influenza virus infection reveals sex bias in invariant natural killer T (iNKT) cells.

Influenza A virus (IAV) infection leads to significant morbidity and mortality. Biological sex influences the immune responses to IAV infection, resulting in higher mortality in women of reproductive age. Previous studies revealed increased activation of T and B cells in female mice after IAV infection, but extensive analysis of sex differences in both innate and adaptive immune cells over time is lacking. Invariant natural killer T (iNKT) cells are fast-reacting forces and modulators of immune responses that are important to IAV immunity, but it is not known if the presence and function of iNKT cells differ between females and males. The aim of this study was to determine immunological mechanisms that contribute to the increased disease severity in female mice during IAV infection. Female and male mice were infected with mouse-adapted IAV and monitored for weight loss and survival. Immune cell populations and cytokine expression in bronchoalveolar lavage fluid, lung, and mediastinal lymph node were determined at three time points after infection using flow cytometry and ELISA. The results reveal increased severity and mortality in adult female mice compared to age-matched males. Female mice show larger increases in innate and adaptive immune cell populations and cytokine production in lung compared to mock on Day 6 postinfection. On Day 9 postinfection, female mice express higher numbers of iNKT cells in lung and liver compared to males. This comprehensive analysis of immune cells and cytokines over time following IAV infection reveals increased leukocyte expansion and stronger proinflammatory cytokine responses in female mice during disease initiation. Furthermore, this is the first study to report a sex bias in iNKT cell populations after IAV infection. The data suggests that the process of recovery from IAV-induced airway inflammation is associated with increased expansion of several different iNKT cell subpopulations in female mice.

Primary Mouse Invariant Natural Killer T (iNKT) Cell Purification and Transduction.

Invariant natural killer T (iNKT) cells are a non-conventional T-cell population expressing a conserved semi-invariant T-cell receptor (TCR) that reacts to lipid antigens, such as α-galactosyl ceramide (α-GalCer), presented by the monomorphic molecule CD1d. iNKT cells play a central role in tumor immunosurveillance and represent a powerful tool for anti-cancer treatment, notably because they can be efficiently redirected against hematological or solid malignancies by engineering with tumor-specific chimeric antigen receptors (CARs) or TCRs. However, iNKT cells are rare and require specific ex vivo pre-selection and substantial in vitro expansion to be exploited for adoptive cell therapy (ACT). This protocol describes a robust method to obtain a large number of mouse iNKT cells that can be effectually engineered by retroviral (RV) transduction. A major advantage of this protocol is that it requires neither particular instrumentation nor a high number of mice. iNKT cells are enriched from the spleens of iVα14-Jα18 transgenic mice; the rapid purification protocol yields a highly enriched iNKT cell population that is activated by anti-CD3/CD28 beads, which is more reproducible and less time consuming than using bone marrow-derived dendritic cells loaded with α-GalCer, without risks of expanding contaminant T cells. Forty-eight hours after activation, iNKT cells are transduced with the selected RV by spin inoculation. This protocol allows to obtain, in 15 days, millions of ready-to-use, highly pure, and stably transduced iNKT cells that might be exploited for in vitro assays and ACT experiments in preclinical studies.

Immunomodulatory Cell Therapy Using αGalCer-Pulsed Dendritic Cells Ameliorates Heart Failure in a Murine Dilated Cardiomyopathy Model.

Dilated cardiomyopathy (DCM) is a life-threatening disease, resulting in refractory heart failure. An immune disorder underlies the pathophysiology associated with heart failure progression. Invariant natural killer T (iNKT) cell activation is a prospective therapeutic strategy for ischemic heart disease. However, its efficacy in nonischemic cardiomyopathy, such as DCM, remains to be elucidated, and the feasible modality for iNKT cell activation in humans is yet to be validated. Dendritic cells isolated from human volunteers were pulsed with α-galactosylceramide ex vivo, which were used as α-galactosylceramide-pulsed dendritic cells (αGCDCs). We treated DCM mice harboring mutated troponin TΔK210/ΔK210 with αGCDCs and evaluated the efficacy of iNKT cell activation on heart failure in DCM mice. Furthermore, we investigated the molecular basis underlying its therapeutic effects in these mice and analyzed primary cardiac cells under iNKT cell-secreted cytokines. The number of iNKT cells in the spleens of DCM mice was reduced compared with that in wild-type mice, whereas αGCDC treatment activated iNKT cells, prolonged survival of DCM mice, and prevented decline in the left ventricular ejection fraction for 4 weeks, accompanied by suppressed interstitial fibrosis. Mechanistically, αGCDC treatment suppressed TGF (transforming growth factor)-β signaling and expression of fibrotic genes and restored vasculature that was impaired in DCM hearts by upregulating angiopoietin 1 (Angpt1) expression. Consistently, IFNγ (interferon gamma) suppressed TGF-β-induced Smad2/3 signaling and the expression of fibrotic genes in cardiac fibroblasts and upregulated Angpt1 expression in cardiomyocytes via Stat1. Immunomodulatory cell therapy with αGCDCs is a novel therapeutic strategy for heart failure in DCM.

Invariant natural killer T cells minimally influence gut microbiota composition in mice

ABSTRACT Invariant Natural Killer T (iNKT) cells are unconventional T cells that respond to glycolipid antigens found in microbes in a CD1d-dependent manner. iNKT cells exert innate-like functions and produce copious amounts of cytokines, chemokines and cytotoxic molecules within only minutes of activation. As such, iNKT cells can fuel or dampen inflammation in a context-dependent manner. In addition, iNKT cells provide potent immunity against bacteria, viruses, parasites and fungi. Although microbiota-iNKT cell interactions are not well-characterized, mounting evidence suggests that microbiota colonization early in life impacts iNKT cell homeostasis and functions in disease. In this study, we showed that CD1d−/− and Vα14 Tg mice, which lack and have increased numbers of iNKT cells, respectively, had no significant alterations in gut microbiota composition compared to their littermate controls. Furthermore, specific iNKT cell activation by glycolipid antigens only resulted in a transient and minimal shift in microbiota composition when compared to the natural drift found in our colony. Our findings demonstrate that iNKT cells have little to no influence in regulating commensal bacteria at steady state. Abbreviations: iNKT: invariant Natural Killer T cell; αGC: α-galactosylceramide

Invariant NKT cells dictate antitumor immunity elicited by a bispecific antibody cotargeting CD3 and BCMA

AbstractCD3-engaging bispecific antibodies (BsAbs) have emerged as powerful therapeutic approaches by their ability to redirect T cells to eliminate tumor cells in a major histocompatibility complex–independent manner. However, how we can potentiate the efficacy of BsAbs remains largely unknown. To address this question, we investigated immunological mechanisms of action of a BsAb cotargeting CD3 and B-cell maturation antigen (BCMA) in syngeneic preclinical myeloma models. Treatment with the CD3/BCMA BsAb stimulated multiple CD3-expressing T-cell subsets and natural killer (NK) cells in the myeloma bone marrow (BM), highlighting its broad immunostimulatory effect. Notably, the BsAb-mediated immunostimulatory and antitumor effects were abrogated in mice lacking invariant NKT (iNKT) cells. Mechanistically, activation of iNKT cells and interleukin-12 production from dendritic cells (DCs) were crucial upstream events for triggering effective antitumor immunity by the BsAb. Myeloma progression was associated with a reduced number of BM iNKT cells. Importantly, the therapeutic efficacy of a single dose of CD3/BCMA BsAb was remarkably augmented by restoring iNKT cell activity, using adoptive transfer of α-galactosylceramide-loaded DCs. Together, these results reveal iNKT cells as critical players in the antitumor activity of CD3 engaging BsAbs and have important translational implications.

Pbrm1 intrinsically controls the development and effector differentiation of iNKT cells.

Under static condition, the pool size of peripheral invariant natural killer T (iNKT) cells is determined by their homeostatic proliferation, survival and thymic input. However, the underlying mechanism is not fully understood. In the present study, we found that the percentage and number of iNKT cells were significantly reduced in the spleen, but not in the thymus of mice with deletion of polybromo‐1 (Pbrm1) compared to wild type (WT) mice. Pbrm1 deletion did not affect iNKT cell proliferation and survival, instead significantly impaired their development from stage 1 to stage 2. Importantly, loss of Pbrm1 led to a dysfunction of RORγt expression and iNKT17 cell differentiation, but not iNKT1 and iNKT2 proportion. Collectively, our study reveals a novel mechanism of Pbrm1 controlling the peripheral size of iNKT cells through regulating their development and differentiation.

Alteration of circulating unconventional T cells in cerebral ischemia: an observational study

Immune reactions provoked by cerebral ischemia play crucial roles in the pathogenesis of brain damage and contribute to tissue regeneration processes. While functions of many immune cell types in post-ischemic inflammation have been well studied in experimental stroke, the exact roles played by unconventional T cells in pathogenesis of the clinical stroke remain to be precisely determined. In the present study, we investigated the frequencies and absolute cell numbers of peripheral blood T lymphocyte subpopulations including those of invariant natural killer T (iNKT) cells, CD3+CD56+ NKT-like (NKTL) cells, and γδ T cells from patients with acute cerebral infarction (ACI), chronic cerebrovascular disease (CCD) or chronic cerebral circulation insufficiency (CCI) by flow cytometry, and analyzed their association with the disease severity and the clinical outcome. We observed significantly reduced cell numbers of circulating iNKT cells, NKTL cells and γδ T cells in cerebral ischemia patients as compared with the healthy controls. Of note, we also demonstrated that numbers of peripheral blood iNKT and γδ T cells are significantly reduced in patients with ACI when compared among different cerebral ischemia patient groups. Moreover, the reduced number of iNKT cells is significantly associated with the disease severity and recovery in cerebral ischemia patients. Our results demonstrate for the first time the reduction of peripheral blood NKTL, iNKT and γδ T cells in patients with the cerebral ischemia, and particularly reduced iNKT and γδ T cells in the acute phase. The reduction of iNKT cells seems to be significantly associated with the disease severity and recovery. We hope that our findings might lead to the identification of predictive and prognostic values of human peripheral unconventional T cell subsets in the cerebral ischemia.

Low Graft Invariant Natural Killer T-Cell Dose Is a Risk Factor for Cytomegalovirus Reactivation After Allogeneic Hematopoietic Cell Transplantation

Cytomegalovirus (CMV) reactivation is common after allogeneic hematopoietic cell transplantation (HCT) and may result in fatal CMV disease. Invariant natural killer T (iNKT) cells are potent modulators of the immune system preventing graft-versus-host disease while promoting graft-versus-leukemia effects. It is thought that iNKT cells selectively influence mediators of both innate and adaptive immunity. Here, we investigated the impact of graft iNKT cells on CMV reactivation in patients undergoing allogeneic HCT. We found a significantly decreased cumulative incidence of CMV reactivation in patients with higher numbers of iNKT cells in the allograft. Therefore iNKT-cell–enriched grafts or adoptive transfer of iNKT cells are compelling cytotherapeutic strategies to improve outcomes after allogeneic HCT.

Progranulin regulates the development and function of NKT2 cells through EZH2 and PLZF.

T helper 2 (Th2) cytokine production by invariant natural killer T (iNKT) cells is involved in the development of asthma, but the regulation of Th2 cytokines in iNKT cells remains unknown. Although it is known that progranulin (PGRN) induces the production of Th2 cytokines in iNKT cells in vivo, the underlying mechanism is not clear. This study aims to investigate the role of PGRN in iNKT cells. The effects of PGRN on the differentiation of iNKT cells was detected by flow cytometry. Then stimulation of iNKT cells and airway resistance were carried out to evaluate the function of PGRN on iNKT cells. Furthermore, the mechanisms of PGRN in regulating iNKT cells was investigated by RT-PCR, WB, confocal and luciferase reporter assays. The absolute number of iNKT cells decreased in PGRN KO mice despite an increase in the percentage of iNKT cells. Furthermore, analyzing the subsets of iNKT cells, we found that NKT2 cells and their IL-4 production were reduced. Mechanistically, the decrease in NKT2 cells in the PGRN KO mice was caused by increased expression of enhancer of zeste homolog 2 (EZH2), that in turn caused increased degradation and altered nuclear localization of PLZF. Interestingly, PGRN signaling decreased expression of EZH2 and treatment of the PGRN KO mice with the EZH2 specific inhibitor GSK343 rescued the defect in NKT2 differentiation, IL-4 generation, and PLZF expression. Altogether, We have revealed a new pathway (PGRN-EZH2-PLZF), which regulates the Th2 responses of iNKT cells and provides a potentially new target for asthma treatment.

Invariant Natural Killer T-cells and their subtypes may play a role in the pathogenesis of endometriosis

ObjectiveTo evaluate the frequencies of iNKT cells and their subsets in patients with deep endometriosis. MethodsA case-control study was conducted between 2013 and 2015, with 73 patients distributed into two groups: 47 women with a histological diagnosis of endometriosis and 26 controls. Peripheral blood, endometriosis lesions, and healthy peritoneal samples were collected on the day of surgery to determine the frequencies of iNKT cells and subtypes via flow cytometry analysis. ResultsThe authors observed a lower number of iNKT (p = 0.01) and Double-Negative (DN) iNKT cells (p = 0.02) in the blood of patients with endometriosis than in the control group. The number of DN iNKT IL-17+ cells in the secretory phase was lower in the endometriosis group (p = 0.049). There was an increase in the secretion of IL-17 by CD4+ iNKT cells in the blood of patients with endometriosis and severe dysmenorrhea (p = 0.038), and severe acyclic pelvic pain (p = 0.048). Patients with severe dysmenorrhea also had a decreased number of CD4+ CCR7+ cells (p = 0.022). ConclusionThe decreased number of total iNKT and DN iNKT cells in patients with endometriosis suggests that iNKT cells play a role in the pathogenesis of endometriosis and can be used to develop new diagnostic and therapeutic agents.