Differentiation Of Lymphoid Cells Research Articles

Microbiota regulates the TET1-mediated DNA hydroxymethylation program in innate lymphoid cell differentiation

Innate lymphoid cell precursors (ILCPs) develop into distinct subsets of innate lymphoid cells (ILCs) with specific functions. The epigenetic program underlying the differentiation of ILCPs into ILC subsets remains poorly understood. Here, we reveal the genome-wide distribution and dynamics of the DNA methylation and hydroxymethylation in ILC subsets and their respective precursors. Additionally, we find that the DNA hydroxymethyltransferase TET1 suppresses ILC1 but not ILC2 or ILC3 differentiation. TET1 deficiency promotes ILC1 differentiation by inhibiting TGF-β signaling. Throughout ILCP differentiation at postnatal stage, gut microbiota contributes to the downregulation of TET1 level. Microbiota decreases the level of cholic acid in the gut, impairs TET1 expression and suppresses DNA hydroxymethylation, ultimately resulting in an expansion of ILC1s. In adult mice, TET1 suppresses the hyperactivation of ILC1s to maintain intestinal homeostasis. Our findings provide insights into the microbiota-mediated epigenetic programming of ILCs, which links microbiota-DNA methylation crosstalk to ILC differentiation.

KCTD5 regulates Ikaros degradation induced by chemotherapeutic drug etoposide in hematological cells.

Therapy-related leukemia carries a poor prognosis, and leukemia after chemotherapy is a growing risk in clinic, whose mechanism is still not well understood. Ikaros transcription factor is an important regulator in hematopoietic cells development and differentiation. In the absence of Ikaros, lymphoid cell differentiation is blocked at an extremely early stage, and myeloid cell differentiation is also significantly affected. In this work, we showed that chemotherapeutic drug etoposide reduced the protein levels of several isoforms of Ikaros including IK1, IK2 and IK4, but not IK6 or IK7, by accelerating protein degradation, in leukemic cells. To investigate the molecular mechanism of Ikaros degradation induced by etoposide, immunoprecipitation coupled with LC-MS/MS analysis was conducted to identify changes in protein interaction with Ikaros before and after etoposide treatment, which uncovered KCTD5 protein. Our further study demonstrates that KCTD5 is the key stabilizing factor of Ikaros and chemotherapeutic drug etoposide induces Ikaros protein degradation through decreasing the interaction of Ikaros with KCTD5. These results suggest that etoposide may induce leukemic transformation by downregulating Ikaros via KCTD5, and our work may provide insights to attenuate the negative impact of chemotherapy on hematopoiesis.

Lateralized response of skull bone marrow via osteopontin signaling in mice after ischemia reperfusion

Skull bone marrow is thought to be an immune tissue closely associated with the central nervous system (CNS). Recent studies have focused on the role of skull bone marrow in central nervous system disorders. In this study, we performed single-cell RNA sequencing on ipsilateral and contralateral skull bone marrow cells after experimental stroke and then performed flow cytometry and analysis of cytokine expression. Skull marrow showed lateralization in response to stroke. Lateralization is demonstrated primarily by the proliferation and differentiation of myeloid and lymphoid lineage cells in the skull bone marrow adjacent to the ischemic region, with an increased proportion of neutrophils compared to monocytes. Analysis of chemokines in the skull revealed marked differences in chemotactic signals between the ipsilateral and contralateral skull, whereas sympathetic signals innervating the skull did not affect cranial bone marrow lateralization. Osteopontin (OPN) is involved in region-specific activation of the skull marrow that promotes inflammation in the meninges, and inhibition of OPN expression improves neurological function.Graphical

Pediatric Patients with Acute Lymphoblastic Leukemia Treated with Blinatumomab in a Real-World Study

Introduction Pediatric B-cell acute lymphoblastic leukemia (B-ALL) involves chromosomal abnormalities and genetic alterations at an early stage of differentiation of lymphoid precursor cells. Most children (~around 80%) with B-ALL can achieve long-term survival with conventional chemotherapy but a sizable number of patients relapse or do not attain complete remission. Blinatumomab is a bispecific T-cell engager antibody designed to redirect CD3+ T cells to bind to CD19+ target cells. Although blinatumomab has been approved for the treatment of relapsed or refractory B-ALL, it has shown efficacy in newly diagnosed B-ALL also. Here, we studied the effect of blinatumomab in newly diagnosed B-ALL (including infantile B-ALL) and post-induction therapy measurable residual disease (MRD) positive B-ALL in a real-world study. Methods Pediatric patients with B-ALL including newly diagnosed infants (infantile type) or with MRD positivity during the induction remission phase, were enrolled. The patients received a 7-day pre-treatment VCP regimen consisting of intravenous infusions of cyclophosphamide 800 mg/m 2 on day 1, vindesine 3 mg/m 2 on day 1, prednisone 1-2 mg/kg on days 1 to 7 (VCP regimen), followed by 28 days of treatment with blinatumomab at 5µg/m 2/day on the first 1 to 7 days and 15 µg/m 2/day on the next 8 to 28 days. Four patients with economic burden received blinatumomab for 14 days: 5µg/m 2/day for days 1 to 4 and 15 µg/m 2/day from day 5 to 14, after pre-treatment with the VCP regimen. Bone marrow assessment of MRD was done on days 14 and 28. Results Between July 2022 and July 2023, 24 pediatric patients received VCP-blinatumomab. Among them, 11 (45.8%) patients had high-risk disease, and 5 (20.8%) had standard risk. The median age of the cohort was 8.5 years. Among the cohort, there was 1 patient with infantile B-ALL and 1 patient with Philadelphia chromosome-positive (Ph+)-ALL; besides 3 patients were TEL-AML positive, 3 patients were CRLF2 positive, 1 patient was E2A-PBX1 positive, 1 patient was SSBP2-CSF1R positive, and 1 patient was EVI1 positive. Blinatumomab was administered to 5 patients in the induction remission period, and for 2 patients, blinatumomab was administered in consolidation after inotuzumab ozogamicin (INO). While 18 patients were treated with blinatumomab for 28 days, 6 patients were treated with blinatumomab for 14 days. Four patients opted for a 14-day regimen due to financial reasons and 2 patients were transplanted with hematopoietic stem cell transplantation after 14 days of treatment with blinatumomab. All the treated patients achieved MRD negativity (100%). There were no ≥ grade 3 treatment-related toxicity and no deaths reported. Conclusion Our study results showed that a 100% MRD negativity rate was achieved in children with B-ALL after treatment with the blinatumomab consolidation following the chemotherapy and no significant safety concerns were observed. Blinatumomab consolidation therapy was also effective in patients pretreated with INO. Blinatumomab consolidation after induction therapy could be a new and effective strategy for the treatment of patients with newly diagnosed B-ALL.

Chenopodium quinoa's Ingredients Improve Control of the Hepatic Lipid Disturbances Derived from a High-Fat Diet.

This study explored the effects of Chenopodium quinoa's ingredients on the major lipids' hepatic profile and the functional selective differentiation of monocyte-derived macrophages and innate lymphoid cells in mice on a high-fat diet. Six-week-old Rag2-/- and Rag2-/-Il2-/- mice received (12 days) a low-molecular-weight protein fraction (LWPF) or the lipid fraction (qLF) obtained from the cold pressing of C. quinoa's germen. At the end of the experiment, mouse serum and liver tissue were collected. The differences in triglycerides, phospholipids, and the major lipids profile were analyzed. Infiltrated monocyte-derived macrophages and innate lymphoid cells (ILCs) and the expression of liver metabolic stress-related mRNA were measured. In the Rag2-/- mice, feeding them LWPF appeared to improve, to a larger extent, their hepatic capacity to utilize fatty acids in comparison to the qLF by preventing the overwhelming of triglycerides (TGs), despite both reducing the hepatic lipid accumulation. An analysis of the hepatic major lipids profile revealed significant increased variations in the PUFAs and phospholipid composition in the Rag2-/- mice fed with the LWPF or LF. The Rag2-/-Il2-/- mice, lacking innate and adaptive lymphocytes, seemed resistant to mobilizing hepatic TGs and unresponsive to lipid accumulation when fed with the LF. Notably, only the Rag2-/- mice fed with the LWPF showed an increased proportion of hepatic CD68+F4/80+ cells population, with a better controlled expression of the innate immune 'Toll-like' receptor (TLR)-4. These changes were associated with an oriented expansion of pluripotential CD117+ cells towards ILC2s (CD117+KLRG1+). Thus, C. quinoa's ingredients resulted in being advantageous for improving the mechanisms for controlling the hepatic lipotoxicity derived from a high-fat diet, promoting liver macrophage and ILCs expansion to a selective functional differentiation for the control of HFD-driven immune and metabolic disturbances.

Maternal polysorbate 80 exposure causes intestinal ILCs and CD4+ T cell developmental abnormalities in mouse offspring

This study aimed to investigate the transgenerational impacts of maternal intake of polysorbate 80 (P80), an emulsifier widely used in modern society, on the development of offspring immunity. Our results revealed that maternal P80 treatment led to impaired differentiation of innate lymphoid cells (ILCs) and CD4+ T cells in the small intestinal lamina propria (SiLP), resulting in intestinal dyshomeostasis in female offspring. Furthermore, we found that SiLP ILCs abundances were significantly altered in 0-day-old fetuses from P80-treated mothers, indicating a prenatal impact of P80-treated mothers on offspring immunity. Additionally, cesarean section and foster-nursing studies demonstrated that P80-induced altered SiLP ILCs in 0-day-old fetuses could further induce dysregulation of ILCs and CD4+ T cells in the SiLP, thus promoting intestinal dysregulation in offspring later in life. Overall, our findings suggest that maternal P80 intake could prenatally program the development of offspring immunity, exerting a significant and long-lasting impact.

Lymphoid cell development from fetal hematopoietic progenitors and human pluripotent stem cells.

Lymphoid cells encompass the adaptive immune system, including T and B cells and Natural killer T cells (NKT), and innate immune cells (ILCs), including Natural Killer (NK) cells. During adult life, these lineages are thought to derive from the differentiation of long-term hematopoietic stem cells (HSCs) residing in the bone marrow. However, during embryogenesis and fetal development, the ontogeny of lymphoid cells is both complex and multifaceted, with a large body of evidence suggesting that lymphoid lineages arise from progenitor cell populations antedating the emergence of HSCs. Recently, the application of single cell RNA-sequencing technologies and pluripotent stem cell-based developmental models has provided new insights into lymphoid ontogeny during embryogenesis. Indeed, PSC differentiation platforms have enabled de novo generation of lymphoid immune cells independently of HSCs, supporting conclusions drawn from the study of hematopoiesis in vivo. Here, we examine lymphoid development from non-HSC progenitor cells and technological advances in the differentiation of human lymphoid cells from pluripotent stem cells for clinical translation.

Top Ten Lymphoproliferative Lesions Not to Miss When Evaluating Oral Ulcer Biopsies.

Oral ulcers represent afull thickness lossof the mucosal epithelium leading to exposure of the submucosal connective tissue. These are common and usually self-limited lesions, although they may sometimes result from neoplasms, most commonly squamous cell carcinoma. Lymphoproliferative disorders may be difficult to diagnose in apthous ulcers since they mimic reactive inflammation. This review presents ten rare oral lymphoid proliferations which should not be missed when assessing oral ulcer biopsies. The ten lesions include several with diagnostic cells which look similar to the histiocytes of a reactive inflammatory ulcer, including Rosai-Dorfman disease, reticulohistiocytoma, Langerhans cell histiocytosis, and traumatic ulcerative granuloma. Other lesions, such as EBV-positive mucocutaneous ulcer, extranodal marginal zone lymphoma of mucosal-associated lymphoid tissue, and plasmablastic lymphoma have lymphoid and/or plasma cell differentiation that mimic the reactive lymphocytes and plasma cells foundin reactive ulcers. Two dendritic cell lesions, follicular dendritic cell sarcoma and blastic plasmacytoid dendritic cell neoplasm, both have distinct phenotypes which are required to make an accurate diagnosis. Each of these lesions are diagnosed by evaluating their histology, along with their phenotypic profile, which is sometimes enhanced by pertinent molecular findings.

The progress in the relationship between trace elements and acute lymphoblastic leukemia.

Trace elements are very important substances with low content in the human body. If the content of some trace elements changes, they are also related to diseases. Acute lymphoblastic leukemia (ALL) is a malignant blood tumor, and its relationship with trace elements has also been a concern by scholars. Not only have the trace element levels in ALL patients changed, but the efficacy of different treatment methods has also been linked to the corresponding trace element changes. The characteristics of ALL may be related to the dysregulation of differentiation and proliferation of lymphoid precursor cells. Cell proliferation and differentiation are often affected by changes in DNA levels. However, trace elements are involved in DNA damage and repair mechanisms. In recent years, as an increasing number of studies believe that ALL is related to the abnormal metabolism of trace elements in the body, this paper intends to discuss the research progress on the relationship between trace elements and ALL to provide more information on trace elements for the diagnosis, treatment, and prevention of ALL.

Correlation of TB LAM Ag (Tuberculosis Lipoarabinomannan Antigen) Results from Urine with Adenosine Deaminase Levels from Pleural Fluid Patients with Pulmonary TB Accompanied by Pleural Effusion

Background: One of the newest testing methods for active TB uses TB LAM Antigen, in which lipoarabinomannan (LAM) as the examined substance serves as the main component of the cell wall of M. tuberculosis (MTB) and the degradation product of MTB by macrophages in the human body. Patients with active TB with or without HIV infection may experience a decreased antibody response, which causes LAM not to bind to antibodies so that it can pass through the normal glomerular basement membrane and can be detected in the urine. Lateral flow urine lipoarabinomannan assay (LF-LAM) can detect this material with urine samples from active TB patients. Another TB screening method uses the measurement of adenosine deaminase (ADA) activity. ADA has a very important function for the proliferation and differentiation of lymphoid cells, especially T cells, and assists in the maturation of monocytes into macrophages. Objective: This study aims to qualitatively prove the correlation between the pleural fluid ADA levels of pulmonary TB patients with pleural effusion using the LF-LAM test results and examine the potential of TB LAM Ag, which correlates with increased pleural fluid ADA levels, as a diagnostic tool for diagnosing pulmonary TB. Method: It is an observational analytic study with a crosssectional design. Materials for this study included temporary urine from active TB patients at Dr. Soetomo Regional Public Hospital collected in May-August 2022. The descriptive analysis was conducted using SPSS 25.0. The data were tested for normal distribution and with the homogeneity test of Shapiro-Wilk's data. The statistical analysis was performed using the Mann-Whitney test, while the kappa suitability test was carried out to determine the correlation and level of concordance between the ADA cut-off value of pleural fluid and the TB LAM Ag test results. Results: This study involved 50 subjects consisting of 22 (44%) subjects with ADA test results between 40-100 IU/L compared to 28 subjects (56%) with ADA test results below 40 IU/L. There were 14 (28%) subjects with positive TB LAM Ag test results, consisting of 10 (45%) active TB subjects with a high ADA test cut-off of 40-100 IU/L and 4 (14%) active TB subjects with a low ADA test cut-off below 40 IU/L, with a p-value = 0.012. Conclusions: There is a correlation between TB Lipoarabinomannan antigen test results of TB patients with pleural effusion. TB LAM Ag can be detected positive on ADA test results of < 40 IU/L and more positive in active TB patients with high ADA test results of > 40-100 IU/L. Therefore, the TB LAM Ag test is more sensitive than the ADA test. The cut-off value of the ADA test reached 76.4 U/L, and a positive TB LAM was found.

INPP5K controls the dynamic structure and signaling of wild-type and mutated, leukemia-associated IL-7 receptors

AbstractThe downstream signaling of the interleukin-7 (IL-7) receptor (IL-7R) plays important physiological and pathological roles, including the differentiation of lymphoid cells and proliferation of acute lymphoblastic leukemia cells. Gain-of-function mutations in the IL-7Rα chain, the specific component of the receptor for IL-7, result in constitutive, IL-7–independent signaling and trigger acute lymphoblastic leukemia. Here, we show that the loss of the phosphoinositide 5-phosphatase INPP5K is associated with increased levels of the INPP5K substrate phosphatidylinositol 4,5-bisphosphate (PtdIns[4,5]P2) and causes an altered dynamic structure of the IL-7 receptor. We discovered that the IL-7Rα chain contains a very conserved positively charged polybasic amino acid sequence in its cytoplasmic juxtamembrane region; this region establish stronger ionic interactions with negatively charged PtdIns(4,5)P2 in the absence of INPP5K, freezing the IL-7Rα chain structure. This dynamic structural alteration causes defects in IL-7R signaling, culminating in decreased expressions of EBF1 and PAX5 transcription factors, in microdomain formation, cytoskeletal reorganization, and bone marrow B-cell differentiation. Similar alterations after the reduced INPP5K expression also affected mutated, constitutively activated IL-7Rα chains that trigger leukemia development, leading to reduced cell proliferation. Altogether, our results indicate that the lipid 5-phosphatase INPP5K hydrolyzes PtdIns(4,5)P2, allowing the requisite conformational changes of the IL-7Rα chain for optimal signaling.

Bcl11b-Edited Lymphoid Progenitors for the Generation of CAR-Engineered Natural Killer-like Cells with Potent Anti-Leukemic Activity

BACKGROUND: The transcription factor B cell CLL/lymphoma 11B (BCL11B) is indispensable for T lineage development of lymphoid progenitors. Tonic signaling of chimeric antigen receptors (CARs) during early phases of in vitro generation of hematopoietic stem cell (HSC)-derived lymphoid progenitors leads to suppressed T cell development and acquisition of NK cell-like properties (CAR-induced killer cells, termed CARiK cells) by suppression of BCL11B. Co-transplantation of CARiK cells into hematopoietic stem cell recipients mediates strong antigen-specific anti-leukemic effects. Here we investigated whether CRISPR/Cas9-based editing of Bcl11b would allow the generation of CARiK cells using clinically more relevant CARs w/o tonic signaling activity. METHODS: Antigen binders against murine CD123 were identified using phage display technology. High affinity binders were cloned into a 2nd generation murine CAR backbone (CD28CD3zeta configuration) and comparatively assessed for expression strength, functionality, specificity, and the lack of tonic signaling activity. Aiming for an all in one vector approach, a sgRNA sequence against Bcl11b was added to the construct for CRISPR-mediated gene disruption. Transduced murine LSK cells were then differentiated into lymphoid CARiK progenitors using the OP9-DLI feeder layer system. Double edited progenitors (8 x 106) and respective controls were co-transplanted into leukemia-bearing murine stem cell recipients. BCL11B suppression was assessed by Western-blotting, correlated with the appearance of a CARiK phenotype, and finally tested for in vivo functionality. RESULTS: A suitable CD123 CAR of high expression strength, specificity, and devoid of tonic signaling was generated. Despite the lack of tonic signaling, early stimulation via CD123 in culture was sufficient for some degree of NK-directed developmental shift. The degree of fratricide was limited. Early Bcl11b disruption allowed for further lymphoid cell differentiation. Bcl11b editing only let to complete BCL11B suppression as did the combined all in one vector construct (Figure 1A). CAR transduction w/o Bcl11b editing resulted in incomplete BCL11B suppression. After transduction with the lentiviral all in one construct, the strongest developmental NK cell shift was observed (Figure 1B). After co-transplantation of CARiK cells up to 100% leukemia free survival was achieved. Low expression strength of CD123 on physiologic hematopoiesis allowed for undisturbed recovery of myelopoiesis as compared to controls. CONCLUSION:Bcl11b editing of hematopoietic stem cell-derived CAR-engineered lymphoid progenitors allows the generation of a NK cell-like cell product with considerable anti-tumor activity. Genetic stability remains to be determined. Figure 1: Natural killer-like cell differentiation of HSC-derived mCD123 CAR-engineered lymphoid progenitors can be enforced by Bcl11b editing. (A) Partial suppression of BCL11B by early CAR-signaling and finally complete disruption by Bcl11b editing as shown by Western Blotting (iTom = neg. control). (B) The extent of BCL11B suppression correlates positively with the amount of NKp46+ cells within the CAR-expressing gate in flow cytometry analysis (n=3). (B) Statistics was performed using Student's t test (2 tailed). Data are shown as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Antitumor Effect of Brusatol in Acute Lymphoblastic Leukemia Models Is Triggered by Reactive Oxygen Species Accumulation.

Acute lymphoblastic leukemia (ALL) is one of the most common hematological malignancies at pediatric ages and is characterized by different chromosomal rearrangements and genetic abnormalities involved in the differentiation and proliferation of lymphoid precursor cells. Brusatol is a quassinoid plant extract extensively studied due to its antineoplastic effect through global protein synthesis and nuclear factor erythroid 2-related factor-2 (NRF2) signaling inhibition. NRF2 is the main regulator of cellular antioxidant response and reactive oxygen species (ROS), which plays an important role in oxidative stress regulation. This study aimed to evaluate the effect of brusatol in in vitro models of ALL. KOPN-8 (B-ALL), CEM (T-ALL), and MOLT-4 (T-ALL) cell lines were incubated with increasing concentrations of brusatol, and the metabolic activity was evaluated using the resazurin assay. Flow cytometry was used to evaluate cell death, cell cycle, mitochondrial membrane potential (Δψmit), and to measure ROS and reduced glutathione (GSH) levels. Our results show that brusatol promoted a decrease in metabolic activity in ALL cell lines in a time-, dose-, and cell-line-dependent manner. Brusatol induced a cytostatic effect by cell cycle arrest in G0/G1 in all cell lines; however, cell death mediated by apoptosis was only observed in T-ALL cells. Brusatol leads to an oxidative stress imbalance by the increase in ROS levels, namely, superoxide anion. Redox imbalance and cellular apoptosis induced by brusatol are highly modulated by mitochondria disruption as a decrease in mitochondrial membrane potential is detected. These data suggest that brusatol might represent a new therapeutic approach for acute lymphoblastic leukemia, particularly for ALL T-cell lineage.

Cytokine Receptor Diversity in the Lamprey Predicts the Minimal Essential Cytokine Networks of Vertebrates.

The vertebrate adaptive immune systems (Agnatha and Gnathostomata) use sets of T and B lymphocyte lineages that somatically generate highly diverse repertoires of Ag-specific receptors and Abs. In Gnathostomata, cytokine networks regulate the activation of lymphoid and myeloid cells, whereas little is known about these components in Agnathans. Most gnathostome cytokines are four-helix bundle cytokines with poorly conserved primary sequences. In contrast, sequence conservation across bilaterians has been observed for cognate cytokine receptor chains, allowing their structural classification into two classes, and for downstream JAK/STAT signaling mediators. With conserved numbers among Gnathostomata, human cytokine receptor chains (comprising 34 class I and 12 class II) are able to interact with 28 class I helical cytokines (including most ILs) and 16 class II cytokines (including all IFNs), respectively. Hypothesizing that the arsenal of cytokine receptors and transducers may reflect homologous cytokine networks, we analyzed the lamprey genome and transcriptome to identify genes and transcripts for 23 class I and five class II cytokine receptors alongside one JAK signal mediator and four STAT transcription factors. On the basis of deduction of their respective orthologs, we predict that these receptors may interact with 16 class I and 3 class II helical cytokines (including IL-4, IL-6, IL-7, IL-12, IL-10, IFN-γ, and thymic stromal lymphoprotein homologs). On the basis of their respective activities in mammals, this analysis suggests the existence of lamprey cytokine networks that may regulate myeloid and lymphoid cell differentiation, including potential Th1/Th2 polarization. The predicted networks thus appear remarkably homologous to those of Gnathostomata, albeit reduced to essential functions.

746P Synergistic antitumor efficacy of INV-71 ROR gamma agonist with immune checkpoint inhibitor anti-PD-1 in a murine orthotopic 4T1 breast cancer model

Retinoic acid-related Orphan Receptor gamma (RORγ) is a transcription factor that controls the differentiation and maintenance of Th17, Tc17, γδ T and innate lymphoid cells. Abundance of Th17+ cells and high levels of the Th17 cytokine IL-17 are associated with good clinical prognosis and outcomes in some cancers. RORγ is a master controller which tightly regulate the expression of genes, including Th17 cytokines, that are critical in enhancing antitumor immunity and inhibiting immune suppression.

Circular RNA circTmem241 drives group III innate lymphoid cell differentiation via initiation of Elk3 transcription

Innate lymphoid cells (ILCs) exert important roles in host defense, tissue repair and inflammatory diseases. However, how ILC lineage specification is regulated remains largely elusive. Here we identify that circular RNA circTmem241 is highly expressed in group III innate lymphoid cells (ILC3s) and their progenitor cells. CircTmem241 deficiency impairs ILC3 commitment and attenuates anti-bacterial immunity. Mechanistically, circTmem241 interacts with Nono protein to recruit histone methyltransferase Ash1l onto Elk3 promoter in ILC progenitor cells (ILCPs). Ash1l-mediated histone modifications on Elk3 promoter enhance chromatin accessibility to initiate Elk3 transcription. Of note, circTmem241−/−, Nono−/− and Ash1l−/− ILCPs display impaired ILC3 differentiation, while Elk3 overexpression rescues ILC3 commitment ability. Finally, circTmem241−/−Elk3−/− mice show lower numbers of ILC3s and are more susceptible to bacterial infection. We reveal that the circTmem241-Nono-Ash1l-Elk3 axis is required for the ILCP differentiation into ILC3P and ILC3 maturation, which is important to manipulate this axis for ILC development on treatment of infectious diseases.

Presence of the GFI1-36N single nucleotide polymorphism enhances the response of MLL-AF9 leukemic cells to CDK4/6 inhibition.

The zinc finger protein Growth Factor Independence 1 (GFI1) acts as a transcriptional repressor regulating differentiation of myeloid and lymphoid cells. A single nucleotide polymorphism of GFI1, GFI1-36N, has a prevalence of 7% in healthy Caucasians and 15% in acute myeloid leukemia (AML) patients, hence most probably predisposing to AML. One reason for this is that GFI1-36N differs from the wildtype form GFI1-36S regarding its ability to induce epigenetic changes resulting in a derepression of oncogenes. Using proteomics, immunofluorescence, and immunoblotting we have now gained evidence that murine GFI1-36N leukemic cells exhibit a higher protein level of the pro-proliferative protein arginine N-methyltransferase 5 (PRMT5) as well as increased levels of the cell cycle propagating cyclin-dependent kinases 4 (CDK4) and 6 (CDK6) leading to a faster proliferation of GFI1-36N leukemic cells in vitro. As a therapeutic approach, we subsequently treated leukemic GFI1-36S and GFI1-36N cells with the CDK4/6 inhibitor palbociclib and observed that GFI1-36N leukemic cells were more susceptible to this treatment. The findings suggest that presence of the GFI1-36N variant increases proliferation of leukemic cells and could possibly be a marker for a specific subset of AML patients sensitive to CDK4/6 inhibitors such as palbociclib.

Notch, RORC and IL-23 signals cooperate to promote multi-lineage human innate lymphoid cell differentiation

Innate lymphoid cells (ILCs) include cytotoxic natural killer cells and distinct groups of cytokine-producing innate helper cells which participate in immune defense and promote tissue homeostasis. Circulating human ILC precursors (ILCP) able to generate all canonical ILC subsets via multi-potent or uni-potent intermediates according to our previous work. Here we show potential cooperative roles for the Notch and IL-23 signaling pathways for human ILC differentiation from blood ILCP using single cell cloning analyses and validate these findings in patient samples with rare genetic deficiencies in IL12RB1 and RORC. Mechanistically, Notch signaling promotes upregulation of the transcription factor RORC, enabling acquisition of Group 1 (IFN-γ) and Group 3 (IL-17A, IL-22) effector functions in multi-potent and uni-potent ILCP. Interfering with RORC or signaling through its target IL-23R compromises ILC3 effector functions but also generally suppresses ILC production from multi-potent ILCP. Our results identify a Notch->RORC- > IL-23R pathway which operates during human ILC differentiation. These observations may help guide protocols to expand functional ILC subsets in vitro with an aim towards novel ILC therapies for human disease.

Transcription factors TCF-1 and GATA3 are key factors for the epigenetic priming of early innate lymphoid progenitors toward distinct cell fates

The differentiation of innate lymphoid cells (ILCs) from hematopoietic stem cells needs to go through several multipotent progenitor stages. However, it remains unclear whether the fates of multipotent progenitors are predefined by epigenetic states. Here, we report the identification of distinct accessible chromatin regions in all lymphoid progenitors (ALPs), EILPs, and ILC precursors (ILCPs). Single-cell MNase-seq analyses revealed that EILPs contained distinct subpopulations epigenetically primed toward either dendritic cell lineages or ILC lineages. We found that TCF-1 and GATA3 co-bound to the lineage-defining sites for ILCs (LDS-Is), whereas PU.1 binding was enriched in the LDSs for alternative dendritic cells (LDS-As). TCF-1 and GATA3 were indispensable for the epigenetic priming of LDSs at the EILP stage. Our results suggest that the multipotency of progenitor cells is defined by the existence of a heterogeneous population of cells epigenetically primed for distinct downstream lineages, which are regulated by key transcription factors.

Hematopoietic Stem and Progenitor Cell Maintenance and Multiple Lineage Differentiation Is an Integral Function of NFATc1.

Hematopoietic stem and progenitor cell (HSPC) maintenance and the differentiation of various lineages is a highly complex but precisely regulated process. Multiple signaling pathways and an array of transcription factors influence HSPC maintenance and the differentiation of individual lineages to constitute a functional hematopoietic system. Nuclear factor of activated T cell (NFAT) family transcription factors have been studied in the context of development and function of multiple mature hematopoietic lineage cells. However, until now their contribution in HSPC physiology and HSPC differentiation to multiple hematopoietic lineages has remained poorly understood. Here, we show that NFAT proteins, specifically NFATc1, play an indispensable role in the maintenance of HSPCs. In the absence of NFATc1, very few HSPCs develop in the bone marrow, which are functionally defective. In addition to HSPC maintenance, NFATc1 also critically regulates differentiation of lymphoid, myeloid, and erythroid lineage cells from HSPCs. Deficiency of NFATc1 strongly impaired, while enhanced NFATc1 activity augmented, the differentiation of these lineages, which further attested to the vital involvement of NFATc1 in regulating hematopoiesis. Hematopoietic defects due to lack of NFATc1 activity can lead to severe pathologies such as lymphopenia, myelopenia, and a drastically reduced lifespan underlining the critical role NFATc1 plays in HSPC maintenance and in the differentaion of various lineages. Our findings suggest that NFATc1 is a critical component of the myriad signaling and transcriptional regulators that are essential to maintain normal hematopoiesis.