Function Of Mature Cells Research Articles

Homeostatic self-MHC-I recognition regulates anti-metastatic function of mature lung natural killer cells

Homeostatic self-MHC-I recognition regulates anti-metastatic function of mature lung natural killer cells

Advanced strategies in 3D bioprinting for vascular tissue engineering and disease modelling using smart bioinks

ABSTRACT Advanced three-dimensional (3D) bioprinting technology enables the precise production of complex vascular structures and biomimetic models, driving advancements in tissue engineering and disease mechanism research. At the core of this technology is smart bioink, which is suitable for fabricating biomimetic models that can be vascularised to meet the property requirements of various tissues. Examples of smart bioinks include decellularized extracellular matrix (dECM), photocrosslinkable, reversible, and microgel-based biphasic (MB) bioinks, whose mechanical properties can be tuned through external stimuli. This tuning helps generate high-resolution and complex-shaped vascular networks essential for cell survival and functional maturation. This review explores advanced 3D bioprinting strategies using smart bioinks for spatially controlled and perfusable vascular in vitro models, emphasising the reconstruction of functional vascular structures within 3D bioprinted models. It also discusses challenges and future prospects, suggesting that 3D bioprinted models could serve as alternatives to traditional animal models for disease modelling and drug screening.

An INSULIN and IAPP dual reporter enables tracking of functional maturation of stem cell-derived insulin producing cells

ObjectiveHuman embryonic stem cell (hESC; SC)-derived pancreatic β cells can be used to study diabetes pathologies and develop cell replacement therapies. Although current differentiation protocols yield SCβ cells with varying degrees of maturation, these cells still differ from deceased donor human β cells in several respects. We sought to develop a reporter cell line that could be used to dynamically track SCβ cell functional maturation. MethodsTo monitor SCβ cell maturation in vitro, we created an IAPP-2A-mScar and INSULIN-2A-EGFP dual fluorescent reporter (INS2A-EGFP/+;IAPP2A-mScarlet/+) hESC line using CRISPR/Cas9. Pluripotent SC were then differentiated using a 7-stage protocol to islet-like cells. Immunohistochemistry, flow cytometry, qPCR, GSIS and electrophysiology were used to characterise resulting cell populations. ResultsWe observed robust expression of EGFP and mScarlet fluorescent proteins in insulin- and IAPP-expressing cells without any compromise to their differentiation. We show that the proportion of insulin-producing cells expressing IAPP increases over a 4-week maturation period, and that a subset of insulin-expressing cells remain IAPP-free. Compared to this IAPP-free population, we show these insulin- and IAPP-expressing cells are less polyhormonal, more glucose-sensitive, and exhibit decreased action potential firing in low (2.8 mM) glucose. ConclusionsThe INS2A-EGFP/+;IAPP2A-mScarlet/+ hESC line provides a useful tool for tracking populations of maturing hESC-derived β cells in vitro. This tool has already been shared with 3 groups and is freely available to all.

An IL-23-STAT4 pathway is required for the proinflammatory function of classical dendritic cells during CNS inflammation

Although many cytokine pathways are important for dendritic cell (DC) development, it is less clear what cytokine signals promote the function of mature dendritic cells. The signal transducer and activator of transcription 4 (STAT4) promotes protective immunity and autoimmunity downstream of proinflammatory cytokines including IL-12 and IL-23. In experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), Stat4-/- mice are resistant to the development of inflammation and paralysis. To define whether STAT4 is required for intrinsic signaling in mature DC function, we used conditional mutant mice in the EAE model. Deficiency of STAT4 in CD11c-expressing cells resulted in decreased T cell priming and inflammation in the central nervous system. EAE susceptibility was recovered following adoptive transfer of wild-type bone marrow-derived DCs to mice with STAT4-deficient DCs, but not adoptive transfer of STAT4- or IL-23R-deficient DCs. Single-cell RNA-sequencing (RNA-seq) identified STAT4-dependent genes in DC subsets that paralleled a signature in MS patient DCs. Together, these data define an IL-23-STAT4 pathway in DCs that is key to DC function during inflammatory disease.

Hippo kinases Mst1 and Mst2 maintain NK cell homeostasis by orchestrating metabolic state and transcriptional activity

Natural killer (NK) cells play a crucial role in immune response against viral infections and tumors. However, further investigation is needed to better understand the key molecules responsible for determining the fate and function of NK cells. In this study, we made an important discovery regarding the involvement of the Hippo kinases Mst1 and Mst2 as novel regulators in maintaining mouse NK cell homeostasis. The presence of high Mst1 and Mst2 (Mst1/2) activity in NK cells is essential for their proper development, survival and function in a canonical Hippo signaling independent mode. Mechanistically, Mst1/2 induce cellular quiescence by regulating the processes of proliferation and mitochondrial metabolism, thereby ensuring the development and survival of NK cells. Furthermore, Mst1/2 effectively sense IL-15 signaling and facilitate the activation of pSTAT3-TCF1, which contributes to NK cell homeostasis. Overall, our investigation highlights the crucial role of Mst1/2 as key regulators in metabolic reprogramming and transcriptional regulation for mouse NK cell survival and function, emphasizing the significance of cellular quiescence during NK cell development and functional maturation.

Molecular Interactions of Selective Agonists and Antagonists with the Retinoic Acid Receptor γ.

All-trans retinoic acid (ATRA), the major active metabolite of all-trans retinol (vitamin A), is a key hormonal signaling molecule. In the adult organism, ATRA has a widespread influence on processes that are crucial to the growth and differentiation of cells and, in turn, the acquisition of mature cell functions. Therefore, there is considerable potential in the use of retinoids to treat diseases. ATRA binds to the retinoic acid receptors (RAR) which, as activated by ATRA, selectively regulate gene expression. There are three main RAR isoforms, RARα, RARβ, and RARγ. They each have a distinct role, for example, RARα and RARγ regulate myeloid progenitor cell differentiation and hematopoietic stem cell maintenance, respectively. Hence, targeting an isoform is crucial to developing retinoid-based therapeutics. In principle, this is exemplified when ATRA is used to treat acute promyelocytic leukemia (PML) and target RARα within PML-RARα oncogenic fusion protein. ATRA with arsenic trioxide has provided a cure for the once highly fatal leukemia. Recent in vitro and in vivo studies of RARγ have revealed the potential use of agonists and antagonists to treat diseases as diverse as cancer, heterotopic ossification, psoriasis, and acne. During the final drug development there may be a need to design newer compounds with added modifications to improve solubility, pharmacokinetics, or potency. At the same time, it is important to retain isotype specificity and activity. Examination of the molecular interactions between RARγ agonists and the ligand binding domain of RARγ has revealed aspects to ligand binding that are crucial to RARγ selectivity and compound activity and key to designing newer compounds.

Sox9 regulates alternative splicing and pancreatic beta cell function

Despite significant research, mechanisms underlying the failure of islet beta cells that result in type 2 diabetes (T2D) are still under investigation. Here, we report that Sox9, a transcriptional regulator of pancreas development, also functions in mature beta cells. Our results show that Sox9-depleted rodent beta cells have defective insulin secretion, and aging animals develop glucose intolerance, mimicking the progressive degeneration observed in T2D. Using genome editing in human stem cells, we show that beta cells lacking SOX9 have stunted first-phase insulin secretion. In human and rodent cells, loss of Sox9 disrupts alternative splicing and triggers accumulation of non-functional isoforms of genes with key roles in beta cell function. Sox9 depletion reduces expression of protein-coding splice variants of the serine-rich splicing factor arginine SRSF5, a major splicing enhancer that regulates alternative splicing. Our data highlight the role of SOX9 as a regulator of alternative splicing in mature beta cell function.

SinCMat: A single-cell-based method for predicting functional maturation transcription factors

A major goal of regenerative medicine is to generate tissue-specific mature and functional cells. However, current cell engineering protocols are still unable to systematically produce fully mature functional cells. While existing computational approaches aim at predicting transcription factors (TFs) for cell differentiation/reprogramming, no method currently exists that specifically considers functional cell maturation processes. To address this challenge, here, we develop SinCMat, a single-cell RNA sequencing (RNA-seq)-based computational method for predicting cell maturation TFs. Based on a model of cell maturation, SinCMat identifies pairs of identity TFs and signal-dependent TFs that co-target genes driving functional maturation. A large-scale application of SinCMat to the Mouse Cell Atlas and Tabula Sapiens accurately recapitulates known maturation TFs and predicts novel candidates. We expect SinCMat to be an important resource, complementary to preexisting computational methods, for studies aiming at producing functionally mature cells.

Isocitrate Dehydrogenase 2 Mutation Allows Myeloid Differentiation but Impairs Bone Marrow Macrophage Polarization and Function Via Metabolic Dysregulation

Isocitrate dehydrogenase 2 (IDH2) mutations, while less common than other mutations associated with myelodysplastic syndromes (MDS), are also found in clonal hematopoiesis and are associated with increased risk of transformation to leukemia. IDH2 mutations lead to metabolic dysfunction and DNA hypermethylation due to the accumulation of D-2-hydroxyglutarate (2HG), an oncometabolite derived from alpha-ketoglutarate (aKG), which disrupts hematopoiesis. However, the mechanisms that induce clonal progression and transformation remain incompletely understood. Furthermore, the intrinsic and extrinsic impact of IDH mutations on mature myeloid cell functions and the bone marrow microenvironment remains to be elucidated. Previous literature suggested that hypermethylation via this mutant leads to incomplete differentiation and failed mature myeloid cell generation. Our lab previously demonstrated that efferocytic defects in bone marrow macrophages can skew hematopoietic stem and progenitor cells via increased inflammatory mediators. Based on these data, we hypothesized that IDH2 mutations prevent complete polarization down pro-efferocytic phenotypes in macrophages due to blocking of metabolic pathways required for mature macrophage function. Congenic CD45.1+ mice were transplanted with retrovirally infected hematopoietic stem cells containing human WT or R172K IDH2 mutant with an mCherry reporter and showed macrocytic anemia, thrombocytopenia, and elevated reticulocytes by 16 weeks post-transplant. In contrast to prior literature, IDH2 mutants gave rise to mature reporter positive monocytes, macrophages, and neutrophils in the bone marrow and peripheral blood. As expected, we observed myeloid skewed hematopoiesis, a trademark of MDS. When cultured ex vivo, there was loss of efferocytic capacity in IDH2 mutant bone marrow macrophages when fed apoptotic neutrophils. We then generated a genetic murine model using the Vav1 Cre IDH2 R140Q floxed mutant. The genetic model allowed us to study disease progression in the absence of radiation induced stress, and to observe mature myeloid populations while clinically defined MDS was absent. We performed ATACseq and bulk RNAseq analysis on bone marrow macrophages isolated from 3-month-old and 6-month-old mice, which demonstrated a significant decrease in global chromosomal accessibility; however, this had limited impact on the transcriptional program. Based on existing literature, the majority of macrophages in the bone marrow are in a poised state and have not yet activated genes associated with pro-efferocytic/pro-resolution or pro-inflammatory phenotypes. Since aKG is accumulated in macrophages during polarization toward reparative and pro-efferocytic phenotypes and is necessary for metabolic reprogramming for oxidative phosphorylation, we hypothesized that, in the presence of IDH2 mutations, which drain aKG from the system, pro-efferocytic polarized macrophages would be metabolically stunned. To test this theory, we isolated bone marrow macrophages from IDH2 mutants and cultured them to generate pro-efferocytic polarized macrophages. We then tested their efferocytic potential and metabolic capacity by seahorse assay. Continual efferocytosis, a hallmark of pro-efferocytic macrophages, was impaired in IDH2 mutant macrophages as early as 2-3 months of age. Consistent with this finding, mito stress testing by seahorse demonstrated that IDH2 mutant macrophages had severely impaired maximal respiratory capacity compared to WT macrophages. Treatment with global hypomethylating agent azacytidine or a cell permeable aKG analog were unable to restore respiratory capacity or efferocytic activity in the IDH2 mutant. These data strongly suggest that the efferocytic defect in IDH2 mutant macrophages is due to metabolic rather than epigenetic reprogramming. In summary, we identify defects in efferocytic function and oxidative phosphorylation in IDH2 mutant macrophages. This represents a novel mechanism that could alter the bone marrow microenvironment and impact progression of MDS and leukemic transformation. Furthermore, our data suggest that the metabolic dysregulation induced by IDH mutations may play a greater role than epigenetic impairment in IDH2 mutant mature myeloid cells, which could explain why approaches targeting hypermethylation have shown limited efficacy in clinical settings.

Tropomyosin 1 Deficiency Facilitates Epithelial-to-Mesenchymal Transitions to Promote Hemogenic Endothelial Specification and Hematopoietic Progenitor Cell Formation

Tropomyosins coat actin filaments and impact many actin-related biology, including signaling and cell morphogenesis. Prior work suggested that TPM1 regulated blood cell formation in vitro, but it was unclear how or when TPM1 affected hematopoiesis. Using gene-edited induced pluripotent stem cell (iPSC)model systems, single cell transcriptomics, and a novel murine model, we aimed to define how and when TPM1 regulated developmental hematopoiesis. We used CRISPR/Cas9 to create TPM1 knockout (KO) iPSC lines in a primitive hematopoiesis system, in which hemogenic endothelial cells spawn hematopoietic progenitor cells (HPC). Western blot showed that TPM1 was highly expressed in iPSCs and endothelial cells but virtually absent in HPCs. TPM1KO enhanced endothelial cell and hematopoietic progenitor cell (HPC) formation without augmenting cell cycle kinetics. RNA sequencing analysis showed that TPM1KO altered epithelial-to-mesenchymal transition (EMT)-related gene expression and functionally enhanced EMT during in vitro hematopoiesis, without generally disrupting normal cell development. Single-cell transcriptomics showed that TPM1 was highly expressed in human and mouse hemogenic endothelium, and abrogated in HPCs, suggesting that TPM1 might also regulate developmental hematopoiesis in vivo similar to our in vitro findings. Indeed, TPM1 expression coincided with EMT-related gene expression during in vivo hematopoiesis (p<1x10-16). To investigate the role of TPM1 in vivo, we used a novel murine TPM1 GeneTrap-Reporter mouse model. By western blot, TPM1 protein was decreased ~50% in peripheral blood. TPM1 GT/GTmice displayed embryonic lethality by E9.5, due to cardiac dysmorphology previously seen in TPM1 knockout mice. TPM1 reporter expression (LacZ) was observed in E9.5 endothelium, temporally consistent with Runx1+/CD31+ hemogenic endothelial cell emergence. Whole-mount imaging of TPM1 GT/+ embryos showed an enhanced percentage (%) of Runx1 + HE at E9.5 and Runx1 +cKit + HPCs at E10.5. Consistent with increased embryonic HPC production, TPM1 GT/+mice showed increased percentages of Lin-Sca1+cKit+ HPCs in bone marrow at 6-8 weeks of age. Complete blood counts in 6-8 weeks-old mice were normal. Conclusions These findings illuminate novel effects of TPM1, a cytoskeletal regulatory molecule, on developmental hematopoiesis. TPM1KO disinhibits EMT to promote hemogenic endothelial specification and HPC production during developmental hematopoiesis, without compromising mature blood cell function. Temporal TPM1 inhibition may offer innovative approaches to enhance blood cell formation in translationally relevant cell culture systems. Our findings may explain genetic associations linking polymorphisms in the TPM1 gene locus with altered human blood traits. More broadly, the radical changes required to form HPCs from endothelial cells during hematopoiesis represent an exciting area of study for actin and tropomyosin biology.

Isocitrate Dehydrogenase 1 Mutation and Ivosidenib in Patients With Acute Myeloid Leukemia: A Comprehensive Review.

Acute myeloid leukemia (AML) arises from immature myeloid progenitors, resulting in a stem-cell-like proliferative state. This leads to excessive pools of immature cells that cannot function, which usually happens at the cost of the production of mature functional cells, leading to deleterious consequences. The management of AML has intensified as newer targeted therapies have come into existence owing to deeper genetic analysis of the disease and patients. Isocitrate dehydrogenase (IDH) is a cytosolic enzyme that is a part of the Krebs cycle and is extremely important in maintaining the homeostasis of the cell. It is produced by two different genes: IDH1 and IDH2. Ivosidenib has been associated with IDH1 inhibition and has been studied in numerous cancers. This review highlights the studies that have dealt with ivosidenib, an IDH1 inhibitor, in AML, the side effect profile, and the possible future course of the drug. After a scoping review of the available literature, we have identified that studies have consistently shown positive outcomes and that ivosidenib is a promising avenue for the management of AML. But it also has to be kept in mind that resistance to IDH inhibitors is on the rise, and the need to identify ways to circumvent this is to be addressed.

Uncoupling of Natural Killer cell functional maturation and cytolytic function in NOD mice.

NK cells are innate immune cells that target infected and tumor cells. Mature NK (mNK) cells undergo functional maturation characterized by four distinct stages, during which they acquire their cytotoxic properties. mNK cells from non-obese diabetic (NOD) mice exhibit a defect in functional maturation and have impaired cytotoxic functions. Hence, we tested whether the impaired cytotoxic function observed in mNK cells from NOD mice can be explained by their defect in functional maturation. By comparing the function of mNK cells from B6, B6g7 and NOD mice, we show that the expression of granzyme B is severely impaired in mNK cells from NOD mice, agreeing with their inability to control tumor growth in vivo. The low level of granzyme B expression in mNK cells from NOD mice is found at all stages of functional maturation and is therefore independent of their functional maturation defect. Consequently, this study demonstrates that phenotypic functional maturation of mNK cells can be uncoupled from the acquisition of cytotoxic functions.

T-BET and EOMES sustain mature human NK cell identity and antitumor function.

Since the T-box transcription factors (TFs) T-BET and EOMES are necessary for initiation of NK cell development, their ongoing requirement for mature NK cell homeostasis, function, and molecular programming remains unclear. To address this, T-BET and EOMES were deleted in unexpanded primary human NK cells using CRISPR/Cas9. Deleting these TFs compromised in vivo antitumor response of human NK cells. Mechanistically, T-BET and EOMES were required for normal NK cell proliferation and persistence in vivo. NK cells lacking T-BET and EOMES also exhibited defective responses to cytokine stimulation. Single-cell RNA-Seq revealed a specific T-box transcriptional program in human NK cells, which was rapidly lost following T-BET and EOMES deletion. Further, T-BET- and EOMES-deleted CD56bright NK cells acquired an innate lymphoid cell precursor-like (ILCP-like) profile with increased expression of the ILC-3-associated TFs RORC and AHR, revealing a role for T-box TFs in maintaining mature NK cell phenotypes and an unexpected role of suppressing alternative ILC lineages. Our study reveals the critical importance of sustained EOMES and T-BET expression to orchestrate mature NK cell function and identity.

Segregation of the stemness program from the proliferation program in intestinal stem cells.

Stem cells can undergo continuous self-renewal and meanwhile retain the stemness capability to differentiate to mature functional cells. However, it is unclear whether the proliferation property can be segregated from the stemness in stem cells. The intestinal epithelium undergoes fast renewal, and the Lgr5+ intestinal stem cells (ISCs) are essential to maintain homeostasis. Here, we report that methyltransferase-like 3 (Mettl3), a critical enzyme for N6-methyladenosine (m6A) methylation, is required for ISCs maintenance as its deletion results in fast loss of stemness markers but has no effect on cell proliferation. We further identify four m6A-modified transcriptional factors, whose ectopic expression can restore stemness gene expression in Mettl3-/- organoids, while their silencing leads to stemness loss. In addition, transcriptomic profiling analysis discerns 23 genes that can be segregated from the genes responsible for cell proliferation. Together, these data reveal that m6A modification sustains ISC stemness, which can be uncoupled from cell proliferation.

Direct Reprogramming of Resident Non-Myocyte Cells and Its Potential for In Vivo Cardiac Regeneration.

Cardiac diseases are the foremost cause of morbidity and mortality worldwide. The heart has limited regenerative potential; therefore, lost cardiac tissue cannot be replenished after cardiac injury. Conventional therapies are unable to restore functional cardiac tissue. In recent decades, much attention has been paid to regenerative medicine to overcome this issue. Direct reprogramming is a promising therapeutic approach in regenerative cardiac medicine that has the potential to provide in situ cardiac regeneration. It consists of direct cell fate conversion of one cell type into another, avoiding transition through an intermediary pluripotent state. In injured cardiac tissue, this strategy directs transdifferentiation of resident non-myocyte cells (NMCs) into mature functional cardiac cells that help to restore the native tissue. Over the years, developments in reprogramming methods have suggested that regulation of several intrinsic factors in NMCs can help to achieve in situ direct cardiac reprogramming. Among NMCs, endogenous cardiac fibroblasts have been studied for their potential to be directly reprogrammed into both induced cardiomyocytes and induced cardiac progenitor cells, while pericytes can transdifferentiate towards endothelial cells and smooth muscle cells. This strategy has been indicated to improve heart function and reduce fibrosis after cardiac injury in preclinical models. This review summarizes the recent updates and progress in direct cardiac reprogramming of resident NMCs for in situ cardiac regeneration.

Hyaluronic acid microparticles for effective spheroid culture and transplantation in liver tissue

Three-dimensional (3D) cell culture is a promising method for maintaining mature cell functions due to its advantageous structural characteristics. Spheroid culture is one of the most commonly used 3D cell culture methods due to its convenience of manufacture. Successful application of spheroids requires that cells survive within the structure and engraft at transplantation sites. This study proposes a new spheroid formation method containing hyaluronic acid (HA) microparticles for 3D cell culture. The spheroids containing HA microparticles showed higher cell migration activity and a higher survival rate and albumin secretion ability after transplantation into the liver of mice, compared to plain spheroids. This 3D cell culture system with HA microparticles in spheroids could be a promising strategy to improve the engraftment and efficiency of cell therapy for regenerative medicine.

Immunotherapy reverses glioma-driven dysfunction of immune system homeostasis

BackgroundGlioma-induced immune dysregulation of the hematopoietic system has been described in a limited number of studies. In this study, our group further demonstrates that gliomas interrupt the cellular differentiation programming...

The role of steroidogenic factor 1 (SF-1) in steroidogenic cell function of the testes and ovaries of mature mice.

The nuclear receptor steroidogenic factor 1 (SF-1) is essential for mature mouse gonad steroidogenic gene expression, for Leydig and Sertoli cell function, and depletion of SF-1 in steroidogenic cells of the testis compromises steroidogenesis, spermatogenesis and male fertility. Steroidogenic factor 1 (SF-1 or NR5A1) plays an essential role in the development of fetal gonads and regulates genes involved in steroid biosynthesis. Since SF-1 is expressed in multiple cell types in mouse gonads, we developed three novel conditional knockout (cKO) mouse models employing Cre-recombinase and floxed alleles of SF-1 (Nr5a1f/f) to identify its role in testes and ovaries of mature mice: Cytochrome P450 17α-hydroxylase (Cyp17Cre/+;Nr5a1f/f, Leydig and theca cell-specific), aromatase (Cyp19Cre/+;Nr5a1f/f, Sertoli and granulosa cell-specific), as well as a combination of both (Cyp17+Cyp19-Cre;Nr5a1f/f). Compared to control animals, Cyp19-Cre;Nr5a1f/f cKO males showed normal fertility and testicular function. The Cyp17Cre/+;Nr5a1f/f cKO males had smaller testis, with drastically reduced Leydig cell volumes and impaired steroidogenesis, though their reproductive performance remained comparable to controls. Some 50% of Cyp17Cre/++Cyp19Cre/+;Nr5a1f/f double-cKO (dKO) males were infertile, while the remaining 50% showed significantly reduced fertility. These dKO males also had smaller testis with degenerative seminiferous tubules, abnormal Leydig cell morphology and lower levels of intra-testicular testosterone. Abnormal Sertoli cell localization was noted in dKO testes, with increased Sox9, p27 and inhibin subunit ßb and decreased androgen receptor expression. Female mice from all genotypes showed normal reproductive capacity, though steroidogenic gene expression levels were significantly decreased in both Cyp17Cre/+;Nr5a1f/f cKO and dKO females. These results show the essential role of SF-1 in mature mouse gonad steroidogenic gene expression, for Leydig and Sertoli cell function, and that depletion SF-1 in all steroidogenic cells of the testis compromises steroidogenesis, spermatogenesis and male fertility.

Transcription factor TOX maintains the expression of Mst1 in controlling the early mouse NK cell development.

Rationale: TOX is a DNA-binding factor required for the development of multiple immune cells and the formation of lymph nodes. However, the temporal regulation mode of TOX on NK cell development and function needs to be further explored. Methods: To investigate the role of TOX in NK cells at distinct developmental phases, we deleted TOX at the hematopoietic stem cell stage (Vav-Cre), NK cell precursor (CD122-Cre) stage and late NK cell developmental stage (Ncr1-Cre), respectively. Flow cytometry was used to detect the development and functional changes of NK cell when deletion of TOX. RNA-seq was used to assess the differences in transcriptional expression profile of WT and TOX-deficient NK cells. Published Chip-seq data was exploited to search for the proteins directly interact with TOX in NK cells. Results: The deficiency of TOX at the hematopoietic stem cell stage severely retarded NK cell development. To a less extent, TOX also played an essential role in the physiological process of NKp cells differentiation into mature NK cells. Furthermore, the deletion of TOX at NKp stage severely impaired the immune surveillance function of NK cells, accompanied by down-regulation of IFN-γ and CD107a expression. However, TOX is dispensable for mature NK cell development and function. Mechanistically, by combining RNA-seq data with published TOX ChIP-seq data, we found that the inactivation of TOX at NKp stage directly repressed the expression of Mst1, an important intermediate kinase in Hippo signaling pathway. Mst1 deficient at NKp stage gained the similar phenotype with Toxfl/flCD122Cre mice. Conclusion: In our study, we conclude that TOX coordinates the early mouse NK cell development at NKp stage by maintaining the expression of Mst1. Moreover, we clarify the different dependence of the transcription factor TOX in NK cells biology.

Inflammatory-driven NK cell maturation and its impact on pathology.

NK cells are innate lymphocytes involved in a large variety of contexts and are crucial in the immunity to intracellular pathogens as well as cancer due to their ability to kill infected or malignant cells. Thus, they harbor a strong potential for clinical and therapeutic use. NK cells do not require antigen exposure to get activated; their functional response is rather based on a balance between inhibitory/activating signals and on the diversity of germline-encoded receptors they express. In order to reach optimal functional status, NK cells go through a step-wise development in the bone marrow before their egress, and dissemination into peripheral organs via the circulation. In this review, we summarize bone marrow NK cell developmental stages and list key factors involved in their differentiation before presenting newly discovered and emerging factors that regulate NK cell central and peripheral maturation. Lastly, we focus on the impact inflammatory contexts themselves can have on NK cell development and functional maturation.