Immunomodulatory soluble HLA-G and HLA-E are associated with rapidly deteriorating CLAD and HCMV-Viremia after Lung-Transplantation.

Plasma-soluble (s)HLA-G and sHLA-E are immunoregulatory proteins that balance the activation of NKG2A+ immune cells. In lung-transplant recipients (LTRs), dysregulated NKG2A+ natural killer cell responses may result in high-level HCMV replication as well as chronic lung allograft dysfunction (CLAD), and especially the development of rapidly deteriorating CLAD is associated with high mortality. We thus analyzed the kinetics and function of sHLA-G and sHLA-E in follow-up samples of N=76 LTRs to evaluate whether these immunoregulatory proteins are associated with the risk for CLAD and high-level HCMV replication. Here, we demonstrate that rapidly deteriorating CLAD LTRs are hallmarked by continually low (<107 ng/mL) sHLA-G levels. In contrast, high sHLA-E levels were associated with the following development of high-level (>1000 copies/mL) HCMV episodes. Thus, sHLA-G and sHLA-E may serve as novel biomarkers for the development of rapidly deteriorating CLAD and high-level HCMV replication in LTRs.

Picroside II promotes HSC apoptosis and inhibits the cholestatic liver fibrosis in Mdr2-/- mice by polarizing M1 macrophages and balancing immune responses.

Liver fibrosis is characterized by chronic inflammatory responses and progressive fibrous scar formation. Macrophages play a central role in the pathogenesis of hepatic fibrosis by reconstructing the immune microenvironment. Picroside II (PIC II), extracted from Picrorhizae Rhizoma, has demonstrated therapeutic potential for various liver damage. However, the mechanisms by which macrophage polarization initiates immune cascades and contributes to the development of liver fibrosis, and whether this process can be influenced by PIC II, remain unclear. In the current study, RNA sequencing and multiple molecular approaches were utilized to explore the underlying mechanisms of PIC II against liver fibrosis in multidrug-resistance protein 2 knockout (Mdr2-/-) mice. Our findings indicate that PIC II activates M1-polarized macrophages to recruit natural killer cells (NK cells), potentially via the CXCL16-CXCR6 axis. Additionally, PIC II promotes the apoptosis of activated hepatic stellate cells (aHSCs) and enhances the cytotoxic effects of NK cells, while also reducing the formation of neutrophil extracellular traps (NETs). Notably, the anti-hepatic fibrosis effects associated with PIC II were largely reversed by macrophage depletion in Mdr2-/- mice. Collectively, our research suggests that PIC II is a potential candidate for halting the progression of liver fibrosis.

Anti-TIM3 chimeric antigen receptor-natural killer cells preferentially target primitive acute myeloid leukemia cells with minimal fratricide and exhaustion.

Acute myeloid leukemia (AML) is an aggressive and genetically heterogeneous disease with poor clinical outcomes. Refractory AML is common, and relapse remains a major challenge, attributable to the presence of therapy-resistant leukemic stem cells (LSCs), which possess self-renewal and repopulating capability. Targeting LSCs is currently the most promising avenue for long-term management of AML. Likewise, chimeric antigen receptor (CAR)-natural killer (NK) cells have emerged as a promising alternative to CAR-T cells due to their intrinsic potential as off-the-shelf products and safer clinical profiles. Here, we introduced a third-generation CAR harboring TIM3 scFv, CD28, 4-1BB, and CD3ζ (CAR-TIM3) into human NK-92 cells, the only FDA-approved NK cell line for clinical trials. TIM3 was chosen as a target antigen owing to its differential expression in LSCs and normal hematopoietic stem/progenitor cells (HSPCs). The established CAR-TIM3 NK-92 cells effectively targeted TIM3 and displayed potent anti-tumor activity against various primitive AML cells, subsequently causing a reduction in leukemic clonogenic growth in vitro, while having minimal effects on HSPCs. CAR-TIM3 NK-92 cells significantly reduced leukemic burden in vivo and interestingly suppressed the engraftment of AML cells into the mouse liver and bone marrow. Surprisingly, we found that CAR-TIM3 NK-92 cells expressed relatively low surface TIM3, leading to a low fratricidal effect. As TIM3 and PD-1 are immune checkpoints involved in NK cell dysfunction, we further tested and found that CAR-TIM3 NK-92 cells are beneficial for alleviating NK cell exhaustion. Our findings highlight the potential application of CAR-TIM3 NK cells for cellular immunotherapy for TIM3+ AML.

Accumulation of CD56+ CD16- Natural Killer Cells in Response to Preoperative Chemotherapy for Breast Cancer.

Background: The activation of the antitumor immune responses of T cells and natural killer (NK) cells is important to induce breast tumor shrinkage via preoperative chemotherapy. We evaluated how antitumor immune responses contribute to the effects of such therapy. Methods: Forty-three patients with stages I - IV breast cancer who underwent surgery between August 2018 and Jun 2023 after preoperative chemotherapy were enrolled. Peripheral natural killer (pNK) cell activity was assessed by 51Cr-release assay, and the counts and percentages of CD4+, CD8+, and NK cells and their subsets in peripheral blood were measured before and after chemotherapy by two-color flow cytometry. Associations of cell population changes with chemotherapy responses were analyzed. Results: On univariate analysis, relative to grade (G) ≤ 1 effects, G ≥ 2 therapeutic effects were associated significantly with human epidermal growth factor receptor 2 (HER-2)+ breast cancer (P = 0.024) and post-chemotherapy CD56+ CD16- NK cell accumulation (8.4% vs. 5.5%, P = 0.042), and tended to be associated with increased pre-chemotherapy CD56+ CD16- NK cell percentages (5.4% vs. 3.3%, P = 0.054) and pNK cell activity (42.0% vs. 34.5%, P = 0.057). The accumulation and increased percentage of CD56+ CD16- NK cells in patients with G ≥ 2 effects were not associated with changes in pNK cell activity or the disappearance of axillary lymph-node metastases. On multivariate analysis, G ≥ 2 therapeutic effects tended to be associated with higher pre-chemotherapy pNK levels (odds ratio = 0.96; 95% confidence interval: 0.921 - 1.002; P = 0.067). Conclusions: The accumulation of the immunoregulatory CD56+ CD16- NK cell subset in the peripheral blood before and after chemotherapy may lead to the production of cytokines that induce an antitumor immune response. Activation of the immune response mediated by CD56+ CD16- pNK cells after chemotherapy and their high counts before chemotherapy may contribute to the improvement of therapeutic effects against breast cancer.

Human yolk sac-derived innate lymphoid-biased multipotent progenitors emerge prior to hematopoietic stem cell formation.

Hematopoietic stem cell (HSC)-independent lymphopoiesis has been elucidated in murine embryos. However, our understanding regarding human embryonic counterparts remains limited. Here, we demonstrated the presence of human yolk sac-derived lymphoid-biased progenitors (YSLPs) expressing CD34, IL7R, LTB, and IRF8 at Carnegie stage 10, much earlier than the first HSC emergence. The number and lymphopoietic potential of these progenitors were both significantly higher in the yolk sac than the embryo proper at this early stage. Importantly, single-cell/bulk culture and CITE-seq have elucidated the tendency of YSLP to differentiate into innate lymphoid cells and dendritic cells. Notably, lymphoid progenitors in fetal liver before and after HSC seeding displayed distinct transcriptional features, with the former closely resembling those of YSLPs. Overall, our data identified the origin, potential, and migratory dynamics of innate lymphoid-biased multipotent progenitors in human yolk sac before HSC emergence, providing insights for understanding the stepwise establishment of innate immune system in humans.

Natural killer cell memory: challenges and opportunities for cancer immunotherapy.

Substantial advancements have been made in recent years in comprehending immune memory, which enhances the secondary response through prior infections. The ability of vertebrate T and B lymphocytes to exhibit classic recall responses has long been regarded as a distinguishing characteristic. However, natural killer (NK) cells have been found to acquire immunological memory in a manner akin to T and B cells. The fundamental principles derived from the investigation of NK cell memory offer novel insights into innate immunity and have the potential to pave the way for innovative strategies to enhance therapeutic interventions against multiple diseases including cancer. Here, we reviewed the fundamental characteristics, memory development and regulatory mechanism of NK cell memory. Moreover, we will conduct a comprehensive evaluation of the accomplishments, obstacles, and future direction pertaining to the utilization of NK cell memory in the field of cancer immunotherapy.

Low Levels of Natural Killer Cell in Newly Diagnosed Myelodysplastic Syndromes Patients May Confer Poor Prognosis: A Retrospective Cohort Study.

Background: Immune imbalance appears to have a critical role in tumor growth according to emerging research. Peripheral lymphocyte subsets are considered to reflect the systemic immune response and clinical prognosis. The prognostic value of lymphocyte subpopulations in myelodysplastic syndrome (MDS) patients remains unclear. Methods: A total of 94 MDS patients were enrolled for the study. X-tile software was performed to determine the prognostic significance of various lymphocyte subpopulations, CD3, CD4, CD8, CD4/CD8 ratio, natural killer cell (NK) and CD19. Among them, the appropriate threshold of NK percent could be found only. Patients were divided into the high NK percent group and the low NK percent group. The prognostic significance was determined by univariate and multivariate Cox hazard models. Results: MDS patients with lower NK level had significantly shorter overall survival (OS). Based on univariate analysis, male gender (P = 0.030), lower HB (<10 g/dl, P = 0.029), higher BM blast (>5%, P < 0.0001), higher-risk IPSS-R cytogenetic (P = 0.032) and lower NK percent (P < 0.0001) were significantly associated with shorter OS. Multivariate Cox proportional hazards regression analysis indicated that low NK was also independent adverse prognostic factor for OS in MDS. Conclusion: Decreased NK level predicts poor prognosis independent of the IPSS-R and provide a novel evaluation factor for MDS patients.

Regulation of the PD-1/PD-L1 Axis and NK Cell Dysfunction by Exosomal miR-552-5p in Gastric Cancer.

OBJECTIVE: NK cells play a vital role in tumor immune resistance. Various factors affect NK cell activity. While NK cell dysfunction has been observed in numerous malignancies, the underlying mechanisms in gastric cancer remain unclear. METHOD: Flow cytometry was used to identify the phenotypic distribution and expression of activated receptors on NK cells. ELISA was used to determine the expression of cytokines. We examined the expression of NK cell-related genes and explored their association with survival and prognosis. Additionally, we conducted PCR detection of miR-552-5p expression levels in plasma exosomes of patients and investigated its correlation with phenotypic distribution and activated receptors. We used flow cytometry and ELISA to verify the role of miR-552-5p in NK cell dysfunction. Furthermore, we investigated the potential role of PD-1/PD-L1 in regulating NK cell dysfunction in patients' cells. RESULTS: We observed a significant decrease in the percentage of NKG2D and NKp30 and IFN-γ and TNF-α in patients than in healthy volunteers. Patients with low levels of CD56, CD16, NKG2D, and NKP46 exhibited poorer survival prognoses. Moreover, increased expression levels of plasma exosomal miR-552-5p in patients were negatively associated with NK cell phenotypic distribution and activated receptor expression. MiR-552-5p downregulated the secretion of perforin, granzyme, and IFN-γ as well as the expression of NKp30, NKp46, and NKG2D. Additionally, it suppressed the cytotoxicity of NK cells. The inhibitory effect of miR-552-5p, on NK cell function was reversed when anti-PD-L1 antibodies were used. CONCLUSION: Exosomal miR-552-5p targets the PD-1/PD-L1 axis, leading to impaired NK cell function.

Natural killer cell-derived exosome-based cancer therapy: from biological roles to clinical significance and implications.

Natural killer (NK) cells are important immune cells in the organism and are the third major type of lymphocytes besides T cells and B cells, which play an important function in cancer therapy. In addition to retaining the tumor cell killing function of natural killer cells, natural killer cell-derived exosomes cells also have the characteristics of high safety, wide source, easy to preserve and transport. At the same time, natural killer cell-derived exosomes are easy to modify, and the engineered exosomes can be used in combination with a variety of current cancer therapies, which not only enhances the therapeutic efficacy, but also significantly reduces the side effects. Therefore, this review summarizes the source, isolation and modification strategies of natural killer cell-derived exosomes and the combined application of natural killer cell-derived engineered exosomes with other antitumor therapies, which is expected to accelerate the clinical translation process of natural killer cell-derived engineered exosomes in cancer therapy.

Blastic Plasmacytoid Dendritic Cell Neoplasm Developed in Chronic Myeloid Leukemia in Molecular Remission During a Four-Year Treatment-Free Interval After Six Years of Dasatinib Treatment.

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare hematological malignancy affecting multiple sites, most commonly the skin. About 10-20% of BPDCN cases are accompanied by hematological neoplasms. A 71-year-old male was diagnosed with chronic myeloid leukemia in the chronic phase (CML-CP) 11 years prior (at 60 years of age), and dasatinib treatment was initiated. A major molecular response (MMR) was achieved 18 months after diagnosis, and the molecular response (MR)4.0 lasted beyond 36 months. Due to pancytopenia, dasatinib was discontinued at 74 months, but the CML-CP remained undetectable. One hundred and twenty-two months after the diagnosis, the patient presented with cutaneous lesions on the forehead and abdomen. Immunological and histological analyses of the skin biopsy showed infiltration of atypical cells from the deep epidermis to the entire dermis, expressing clusters of differentiation (CD) 4, CD56, and CD123 without any other markers. The same cells were observed in bone marrow samples. BPDCN was diagnosed, followed by chemotherapy and possibly autologous or allogeneic hematopoietic stem cell transplantation (HSCT). To the best of our knowledge, this is the first case report of the development of BPDCN in a patient with CML in molecular remission. Further studies are required to clarify the pathogenesis of BPDCN in patients with hematological malignancies in remission.

Decreased Peripheral Blood Natural Killer Cell Count in Untreated Juvenile Dermatomyositis Is Associated with Muscle Weakness.

Juvenile Dermatomyositis (JDM) is the most common inflammatory myopathy in pediatrics. This study evaluates the role of Natural Killer (NK) cells in Juvenile Dermatomyositis (JDM) pathophysiology. The study included 133 untreated JDM children with an NK cell count evaluation before treatment. NK cell subsets (CD56low/dim vs. CD 56bright) were examined in 9 untreated children. CD56 and perforin were evaluated in situ in six untreated JDM and three orthopedic, pediatric controls. 56% of treatment-naive JDM had reduced circulating NK cell counts, designated "low NK cell". This low NK group had more active muscle disease compared to the normal NK cell group. The percentage of circulating CD56low/dim NK cells was significantly lower in the NK low group than in controls (0.55% vs. 4.6% p < 0.001). Examination of the untreated JDM diagnostic muscle biopsy documented an increased infiltration of CD56 and perforin-positive cells (p = 0.023, p = 0.038, respectively). Treatment-naive JDM with reduced circulating NK cell counts exhibited more muscle weakness and higher levels of serum muscle enzymes. Muscle biopsies from treatment-naive JDM displayed increased NK cell infiltration, with increased CD56 and perforin-positive cells.

LILRB1-HLA-G axis defines a checkpoint driving natural killer cell exhaustion in tuberculosis.

Chronic infections, including Mycobacterium tuberculosis (Mtb)-caused tuberculosis (TB), can induce host immune exhaustion. However, the key checkpoint molecules involved in this process and the underlying regulatory mechanisms remain largely undefined, which impede the application of checkpoint-based immunotherapy in infectious diseases. Here, through adopting time-of-flight mass cytometry and transcriptional profiling to systematically analyze natural killer (NK) cell surface receptors, we identify leukocyte immunoglobulin like receptor B1 (LILRB1) as a critical checkpoint receptor that defines a TB-associated cell subset (LILRB1+ NK cells) and drives NK cell exhaustion in TB. Mechanistically, Mtb-infected macrophages display high expression of human leukocyte antigen-G (HLA-G), which upregulates and activates LILRB1 on NK cells to impair their functions by inhibiting mitogen-activated protein kinase (MAPK) signaling via tyrosine phosphatases SHP1/2. Furthermore, LILRB1 blockade restores NK cell-dependent anti-Mtb immunity in immuno-humanized mice. Thus, LILRB1-HLA-G axis constitutes a NK cell immune checkpoint in TB and serves as a promising immunotherapy target.

The HHV-6B U20 glycoprotein binds ULBP1, masking it from recognition by NKG2D and interfering with natural killer cell activation.

Introduction: Human Herpesvirus 6B (HHV-6B) impedes host immune responses by downregulating class I MHC molecules (MHC-I), hindering antigen presentation to CD8+ T cells. Downregulation of MHC-I disengages inhibitory receptors on natural killer (NK) cells, resulting in activation and killing of the target cell if NK cell activating receptors such as NKG2D have engaged stress ligands upregulated on the target cells. Previous work has shown that HHV-6B downregulates three MHC-like stress ligands MICB, ULBP1, and ULBP3, which are recognized by NKG2D. The U20 glycoprotein of the related virus HHV-6A has been implicated in the downregulation of ULBP1, but the precise mechanism remains undetermined. Methods: We set out to investigate the role of HHV-6B U20 in modulating NK cell activity. We used HHV-6B U20 expressed as a recombinant protein or transduced into target cells, as well as HHV-6B infection, to investigate binding interactions with NK cell ligands and receptors and to assess effects on NK cell activation. Small-angle X-ray scattering was used to align molecular models derived from machine-learning approaches. Results: We demonstrate that U20 binds directly to ULBP1 with sub-micromolar affinity. Transduction of U20 decreases NKG2D binding to ULBP1 at the cell surface but does not decrease ULBP1 protein levels, either at the cell surface or in toto. HHV-6B infection and soluble U20 have the same effect. Transduction of U20 blocks NK cell activation in response to cell-surface ULBP1. Structural modeling of the U20 - ULBP1 complex indicates some similarities to the m152-RAE1γ complex.

Natural Killer Cell Presence in Antibody-Mediated Rejection.

Transcript analyses highlight an important contribution of natural killer (NK) cells to microvascular inflammation (MVI) in antibody-mediated rejection (ABMR), but only few immunohistologic studies have quantified their spatial distribution within graft tissue. This study included 86 kidney transplant recipients who underwent allograft biopsies for a positive donor-specific antibody (DSA) result. NK cells were visualized and quantified within glomeruli and peritubular capillaries (PTC), using immunohistochemistry for CD34 alongside CD16/T-bet double-staining. Staining results were analyzed in relation to histomorphology, microarray analysis utilizing the Molecular Microscope Diagnostic System, functional NK cell genetics, and clinical outcomes. The number of NK cells in glomeruli per mm2 glomerular area (NKglom) and PTC per mm2 cortical area (NKPTC) was substantially higher in biopsies with ABMR compared to those without rejection, and correlated with MVI scores (NKglom Spearman's correlation coefficient [SCC] = 0.55, p < 0.001, NKPTC 0.69, p < 0.001). In parallel, NK cell counts correlated with molecular classifiers reflecting ABMR activity (ABMRprob: NKglom 0.59, NKPTC 0.75) and showed a trend towards higher levels in association with high functional FCGR3A and KLRC2 gene variants. Only NKPTC showed a marginally significant association with allograft function and survival. Our immunohistochemical results support the abundance of NK cells in DSA-positive ABMR.

Technical considerations and strategies for generating and optimizing humanized mouse tumor models in immuno-oncology research.

The field of cancer immunotherapy has experienced significant progress, resulting in the emergence of numerous biological drug candidates requiring in vivo efficacy testing and a better understanding of their mechanism of action (MOA). Humanized immune system (HIS) models are valuable tools in this regard. However, there is a lack of systematic guidance on HIS modeling. To address this issue, the present study aimed to establish and optimize a variety of HIS models for immune-oncology (IO) study, including genetically engineered mouse models and HIS models with human immune components reconstituted in severely immunocompromised mice. The efficacy and utility of these models were tested with several marketed or investigational IO drugs according to their MOA, followed by immunophenotypic analysis and efficacy evaluation. The results of the present study demonstrated that the HIS models responded to various IO drugs as expected and that each model had unique niches, utilities and limitations. Researchers should carefully choose the appropriate models based on the MOA and the targeted immune cell populations of the investigational drug. The present study provides valuable methodologies and actionable technical guidance on designing, generating or utilizing appropriate HIS models to address specific questions in translational IO.

In Vivo PET Imaging of 89Zr-Labeled Natural Killer Cells and the Modulating Effects of a Therapeutic Antibody.

Natural killer (NK) cells can kill cancer cells via antibody-dependent cell-mediated cytotoxicity (ADCC): a tumor-associated IgG antibody binds to the Fcγ receptor CD16 on NK cells via the antibody Fc region and activates the cytotoxic functions of the NK cell. Here, we used PET imaging to assess NK cell migration to human epidermal growth factor receptor 2 (HER2)-positive HCC1954 breast tumors, examining the influence of HER2-targeted trastuzumab antibody treatment on NK cell tumor accumulation. Methods: Human NK cells from healthy donors were expanded ex vivo and labeled with [89Zr]Zr-oxine. In vitro experiments compared the phenotypic markers, viability, proliferation, migration, degranulation, and ADCC behaviors of both labeled (89Zr-NK) and unlabeled NK cells. Female mice bearing orthotopic human breast HCC1954 tumors were administered 89Zr-NK cells alongside trastuzumab treatment or a sham treatment and then scanned using PET/CT imaging over 7 d. Flow cytometry and γ-counting were used to analyze the presence of 89Zr-NK cells in liver and spleen tissues. Results: 89Zr cell radiolabeling yields measured 42.2% ± 8.0%. At an average specific activity of 16.7 ± 4.7 kBq/106 cells, 89Zr-NK cells retained phenotypic and functional characteristics including CD56 and CD16 expression, viability, migration, degranulation, and ADCC capabilities. In vivo PET/CT studies indicated predominant accumulation of 89Zr-NK cells in the liver and spleen. Ex vivo analyses of liver and spleen tissues indicated that the administered human 89Zr-NK cells retained their radioactivity in vivo and that 89Zr did not transfer to cells of murine soft tissues, thus validating this 89Zr PET method for NK cell tracking. Notably, 89Zr-NK cells migrated to HER2-positive tumors, both with and without trastuzumab treatment. Trastuzumab treatment was associated with an increased 89Zr-NK cell signal at days 1 and 3 after injection. Conclusion: In vitro, 89Zr-NK cells maintained key cellular and cytotoxic functions. In vivo, 89Zr-NK cells trafficked to HER2-postive tumors, with trastuzumab treatment correlating with enhanced 89Zr-NK infiltration. This study demonstrates the feasibility of using PET to image 89Zr-NK cell infiltration into solid tumors.

Effect of preoperative natural killer cell on postoperative pulmonary complications in patients of lung cancer - A single-center retrospective cohort study.

BACKGROUND: The effect of preoperative natural killer (NK) cell abnormalities on postoperative pulmonary complications (PPCs) after thoracoscopic radical resection of lung cancer is still unclear. The main purpose of this study was to investigate the relationship between the preoperative NK cell ratio and PPCs. METHODS: The patients who underwent thoracoscopic radical resection for lung cancer were divided into a normal group and an abnormal group according to whether the proportion of preoperative NK cells was within the reference range. The main outcome was the incidence of PPCs during postoperative hospitalization. The demographic and perioperative data were collected. Propensity score matching was used to exclude systematic bias. Univariate logistic regression was used to test the relationship between the preoperative NK cell ratio and the incidence of PPCs. The restrictive cubic spline curve was used to analyze the dose-effect relationship between the preoperative NK cell ratio and the incidence of PPCs. RESULTS: A total of 4161 patients were included. After establishing a matching cohort, 910 patients were included in the statistical analysis. The incidence of PPCs in the abnormal group was greater than that in the normal group (55.2% vs. 31.6%). The incidence of PPCs first decreased and then increased with increasing NK cell ratio. The proportion of patients with Grade 3 or higher PPCs in the normal group was lower than that in the abnormal group [108 (23.7%) vs. 223 (49%)]. The indwelling time of the thoracic drainage tube in the abnormal group was longer than that in the normal group [3 (3, 4) vs. 3 (3, 5)]. A preoperative abnormal NK cell ratio constituted a risk factor for PPCs in each subgroup. CONCLUSION: Lung cancer patients with an abnormal proportion of peripheral blood NK cells before surgery were more likely to develop PPCs, their disease degree was more severe, and they had a prolonged duration of chest tube indwelling. Compared with those with abnormally high NK cell ratios, those with abnormally low NK cell ratios had more pronounced PPCs.

Antileukemia Activity of Human Natural Killer Cell-Derived Nanomagic Bullets against Acute Myeloid Leukemia (AML).

Background: Cancer is among the serious health problems of the medical world, for treatment of which severe treatments are used. However, the prognosis of cancer patients is still poor. The application of NK cell-derived exosomes (NK-Exo) is a new method for cancer immunotherapy. These nanoparticles with a size range of 30-120 nm are a small model of mother cells. In this study, the anti-tumor activity of NK-Exo and LAK-Exo (activated NK cell-derived exosome) against acute myeloid leukemia (AML) is investigated in vitro. Materials and Methods: The MACS method was performed for the separation of NK cells from the buffy coats of healthy donors, and an EXOCIBE kit was used for the isolation of NK-Exo. After treating the KG-1 cell line with different doses of NK-Exo, MTT assay, and annexin V-PE were done to evaluate cell proliferation and apoptosis, respectively, and for confirmation of involved proteins, Real-Time PCR and western blotting were performed. Results: Anti-tumor activity of NK-Exo and LAK-Exo was dose- and time-dependent. Their highest activities were observed following 48 hours of incubation with 50 µg/ml exosome (p<0.0001). However, this cytotoxic activity was also seen over a short period of time with low concentrations of NK-Exo (p<0.05) and LAK-Exo (p<0.001).The cytotoxic effect of LAK-Exo on target cells was significantly higher than NK-EXO. The induction of apoptosis by different pathways was time-point dependent. Total apoptosis was 34.56% and 51.6% after 48 hours of tumor cell coculture with 50µg/ml NK-Exo and LAK-Exo, respectively. Significant expression of CASPASE3, P38, and CYTOCHROME C genes was observed in the cells treated with 50 µg/ml NK-Exo and LAK-Exo. Conclusion: Our study confirmed the antileukemia activity of NK-Exo against AML tumor cells in vitro. Therefore, NK-Exo can be considered as a promising and effective treatment for leukemia therapy.

Converging peripheral blood microRNA profiles in Parkinson's disease and progressive supranuclear palsy.

MicroRNAs act via targeted suppression of messenger RNA translation in the DNA-RNA-protein axis. The dysregulation of microRNA(s) reflects the epigenetic changes affecting the cellular processes in multiple disorders. To understand the complex effect of dysregulated microRNAs linked to neurodegeneration, we performed a cross-sectional microRNA expression analysis in idiopathic Parkinson's disease (n = 367), progressive supranuclear palsy (n = 35) and healthy controls (n = 416) from the Luxembourg Parkinson's Study, followed by prediction modelling, enriched pathway analysis and target simulation of dysregulated microRNAs using probabilistic Boolean modelling. Forty-six microRNAs were identified to be dysregulated in Parkinson's disease versus controls and 16 in progressive supranuclear palsy versus controls with 4 overlapping significantly dysregulated microRNAs between the comparisons. Predictive power of microRNA subsets (including up to 100 microRNAs) was modest for differentiating Parkinson's disease or progressive supranuclear palsy from controls (maximal cross-validated area under the receiver operating characteristic curve 0.76 and 0.86, respectively) and low for progressive supranuclear palsy versus Parkinson's disease (maximal cross-validated area under the receiver operating characteristic curve 0.63). The enriched pathway analysis revealed natural killer cell pathway to be dysregulated in both, Parkinson's disease and progressive supranuclear palsy versus controls, indicating that the immune system might play an important role in both diseases. Probabilistic Boolean modelling of pathway dynamics affected by dysregulated microRNAs in Parkinson's disease and progressive supranuclear palsy revealed partially overlapping dysregulation in activity of the transcription factor EB, endoplasmic reticulum stress signalling, calcium signalling pathway, dopaminergic transcription and peroxisome proliferator-activated receptor gamma coactivator-1α activity, though involving different mechanisms. These findings indicated a partially convergent (sub)cellular end-point dysfunction at multiple levels in Parkinson's disease and progressive supranuclear palsy, but with distinctive underlying molecular mechanisms.

DNA demethylase Tet2 promotes the terminal maturation of natural killer cells.

The cytotoxicity feature to eliminate malignant cells makes natural killer (NK) cells a candidate for tumor immunotherapy. However, this scenario is currently hampered by inadequate understanding of the regulatory mechanisms of NK cell development. Ten-Eleven-Translocation 2 (Tet2) is a demethylase whose mutation was recently shown to cause phenotypic defects in NK cells. However, the role of Tet2 in the development and maturation of NK cells is not entirely clear. Here we studied the modulatory role of Tet2 in NK cell development and maturation by generating hematopoietic Tet2 knockout mice and mice with Tet2 conditional deletion in NKp46+ NK cells. The results showed that both hematopoietic and NK cell conditional deletion of Tet2 had no effect on the early steps of NK cell development, but impaired the terminal maturation of NK cells defined by CD11b, CD43, and KLRG1 expression. In the liver, Tet2 deletion not only prevented the terminal maturation of NK cells, but also increased the proportion of type 1 innate lymphoid cells (ILC1s) and reduced the proportion of conventional NK cells (cNK). Moreover, hematopoietic deletion of Tet2 lowered the protein levels of perforin in NK cells. Furthermore, hematopoietic deletion of Tet2 downregulated the protein levels of Eomesodermin (Eomes), but not T-bet, in NK cells. In conclusion, our results demonstrate that Tet2 plays an important role in the terminal maturation of NK cells, and the Eomes transcription factor may be involved.