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PloS One 2024Our previous research demonstrated that PU.1 regulates expression of the genes involved in inflammation in macrophages. Selective knockdown of PU.1 in macrophages...
Our previous research demonstrated that PU.1 regulates expression of the genes involved in inflammation in macrophages. Selective knockdown of PU.1 in macrophages ameliorated LPS-induced acute lung injury (ALI) in bone marrow chimera mice. Inhibitors that block the transcriptional activity of PU.1 in macrophages have the potential to mitigate the pathophysiology of LPS-induced ALI. However, complete inactivation of PU.1 gene disrupts normal myelopoiesis. Although the green tea polyphenol Epigallocatechin gallate (EGCG) has been shown to regulate inflammatory genes in various cell types, it is not known if EGCG alters the transcriptional activity of PU.1 protein. Using Schrodinger Glide docking, we have identified that EGCG binds with PU.1 protein, altering its DNA-binding and self-dimerization activity. In silico analysis shows that EGCG forms Hydrogen bonds with Glutamic Acid 209, Leucine 250 in DNA binding and Lysine 196, Tryptophan 193, and Leucine 182 in the self-dimerization domain of the PU.1 protein. Experimental validation using mouse bone marrow-derived macrophages (BMDM) confirmed that EGCG inhibits both DNA binding by PU.1 and self-dimerization. Importantly, EGCG had no impact on expression of the total PU.1 protein levels but significantly reduced expression of various inflammatory genes and generation of ROS. In summary, we report that EGCG acts as an inhibitor of the PU.1 transcription factor in macrophages.
Topics: Catechin; Animals; Trans-Activators; Macrophages; Proto-Oncogene Proteins; Mice; Mice, Inbred C57BL; Molecular Docking Simulation; Protein Binding; DNA; Gene Expression Regulation; Lipopolysaccharides
PubMed: 38662666
DOI: 10.1371/journal.pone.0301904 -
The FEBS Journal Apr 2024l-threonine dehydrogenase (Tdh) is an enzyme that links threonine metabolism to epigenetic modifications and mitochondria biogenesis. In vitro studies show that it is...
l-threonine dehydrogenase (Tdh) is an enzyme that links threonine metabolism to epigenetic modifications and mitochondria biogenesis. In vitro studies show that it is critical for the regulation of trimethylation of histone H3 lysine 4 (H3K4me3) levels and cell fate determination of mouse embryonic stem cells (mESCs). However, whether Tdh regulates a developmental process in vivo and, if it does, whether it also primarily regulates H3K4me3 levels in this process as it does in mESCs, remains elusive. Here, we revealed that, in zebrafish hematopoiesis, tdh is preferentially expressed in neutrophils. Knockout of tdh causes a decrease in neutrophil number and slightly suppresses their acute injury-induced migration, but, unlike the mESCs, the level of H3K4me3 is not evidently reduced in neutrophils sorted from the kidney marrow of adult tdh-null zebrafish. These phenotypes are dependent on the enzymatic activity of Tdh. Importantly, a soluble supplement of nutrients that are able to fuel the acetyl-CoA pool, such as pyruvate, glucose and branched-chain amino acids, is sufficient to rescue the reduction in neutrophils caused by tdh deletion. In summary, our study presents evidence for the functional requirement of Tdh-mediated threonine metabolism in a developmental process in vivo. It also provides an animal model for investigating the nutritional regulation of myelopoiesis and immune response, as well as a useful tool for high-throughput drug/nutrition screening.
PubMed: 38652546
DOI: 10.1111/febs.17138 -
JCI Insight Apr 2024Acute myeloid leukemia (AML) is a fatal disease characterized by the accumulation of undifferentiated myeloblasts, and agents that promote differentiation have been...
Acute myeloid leukemia (AML) is a fatal disease characterized by the accumulation of undifferentiated myeloblasts, and agents that promote differentiation have been effective in this disease but are not curative. Dihydroorotate dehydrogenase inhibitors (DHODHi) have the ability to promote AML differentiation and target aberrant malignant myelopoiesis. We introduce HOSU-53, a DHODHi with significant monotherapy activity, which is further enhanced when combined with other standard-of-care therapeutics. We further discovered that DHODHi modulated surface expression of CD38 and CD47, prompting the evaluation of HOSU-53 combined with anti-CD38 and anti-CD47 therapies, where we identified a compelling curative potential in an aggressive AML model with CD47 targeting. Finally, we explored using plasma dihydroorotate (DHO) levels to monitor HOSU-53 safety and found that the level of DHO accumulation could predict HOSU-53 intolerability, suggesting the clinical use of plasma DHO to determine safe DHODHi doses. Collectively, our data support the clinical translation of HOSU-53 in AML, particularly to augment immune therapies. Potent DHODHi to date have been limited by their therapeutic index; however, we introduce pharmacodynamic monitoring to predict tolerability while preserving antitumor activity. We additionally suggest that DHODHi is effective at lower doses with select immune therapies, widening the therapeutic index.
Topics: Leukemia, Myeloid, Acute; Humans; Pyrimidines; Mice; Animals; Dihydroorotate Dehydrogenase; Immunotherapy; Cell Line, Tumor; Xenograft Model Antitumor Assays; Female
PubMed: 38646934
DOI: 10.1172/jci.insight.173646 -
Immunity May 2024Signaling through Notch receptors intrinsically regulates tumor cell development and growth. Here, we studied the role of the Notch ligand Jagged2 on immune evasion in...
Signaling through Notch receptors intrinsically regulates tumor cell development and growth. Here, we studied the role of the Notch ligand Jagged2 on immune evasion in non-small cell lung cancer (NSCLC). Higher expression of JAG2 in NSCLC negatively correlated with survival. In NSCLC pre-clinical models, deletion of Jag2, but not Jag1, in cancer cells attenuated tumor growth and activated protective anti-tumor T cell responses. Jag2 lung tumors exhibited higher frequencies of macrophages that expressed immunostimulatory mediators and triggered T cell-dependent anti-tumor immunity. Mechanistically, Jag2 ablation promoted Nr4a-mediated induction of Notch ligands DLL1/4 on cancer cells. DLL1/4-initiated Notch1/2 signaling in macrophages induced the expression of transcription factor IRF4 and macrophage immunostimulatory functionality. IRF4 expression was required for the anti-tumor effects of Jag2 deletion in lung tumors. Antibody targeting of Jagged2 inhibited tumor growth and activated IRF4-driven macrophage-mediated anti-tumor immunity. Thus, Jagged2 orchestrates immunosuppressive systems in NSCLC that can be overcome to incite macrophage-mediated anti-tumor immunity.
Topics: Jagged-2 Protein; Animals; Lung Neoplasms; Carcinoma, Non-Small-Cell Lung; Mice; Humans; Interferon Regulatory Factors; Tumor-Associated Macrophages; Mice, Knockout; Signal Transduction; Calcium-Binding Proteins; Cell Line, Tumor; Mice, Inbred C57BL; Receptors, Notch; Receptor, Notch1; Macrophages; Jagged-1 Protein; Tumor Escape
PubMed: 38636522
DOI: 10.1016/j.immuni.2024.03.020 -
Immunological Reviews May 2024Innate immune memory endows innate immune cells with antigen independent heightened responsiveness to subsequent challenges. The durability of this response can be... (Review)
Review
Innate immune memory endows innate immune cells with antigen independent heightened responsiveness to subsequent challenges. The durability of this response can be mediated by inflammation induced epigenetic and metabolic reprogramming in hematopoietic stem and progenitor cells (HSPCs) that are maintained through differentiation to mature immune progeny. Understanding the mechanisms and extent of trained immunity induction by pathogens and vaccines, such as BCG, in HSPC remains a critical area of exploration with important implications for health and disease. Here we review these concepts and present new analysis to highlight how inflammatory reprogramming of HSPC can potently alter immune tone, including to enhance specific anti-tumor responses. New findings in the field pave the way for novel HSPC targeting therapeutic strategies in cancer and other contexts of immune modulation. Future studies are expected to unravel diverse and extensive effects of infections, vaccines, microbiota, and sterile inflammation on hematopoietic progenitor cells and begin to illuminate the broad spectrum of immunologic tuning that can be established through altering HSPC phenotypes. The purpose of this review is to draw attention to emerging and speculative topics in this field where we posit that focused study of HSPC in the framework of trained immunity holds significant promise.
Topics: Humans; Hematopoietic Stem Cells; Animals; Cellular Reprogramming; Immunity, Innate; Immunologic Memory; Cell Differentiation; Epigenesis, Genetic; Inflammation; Neoplasms
PubMed: 38632868
DOI: 10.1111/imr.13335 -
American Journal of Hematology Jul 2024Polycythemia vera (PV) is a clonal disorder arising from the acquired somatic mutations of the JAK2 gene, including JAK2 or several others in exon 12. A 38-year-old...
Polycythemia vera (PV) is a clonal disorder arising from the acquired somatic mutations of the JAK2 gene, including JAK2 or several others in exon 12. A 38-year-old female had a stroke at age 32 and found to have elevated hemoglobin, normal leukocytes, normal platelets, and tested negative for JAK2 and exon 12 mutations. Next generation sequencing revealed a novel mutation: JAK2 in the pseudokinase domain (JH2) at 47.5%. Its presence in her nail DNA confirmed a germline origin. Her mother and her son similarly had erythrocytosis and a JAK2 mutation. Computer modeling indicated gain-of-function JAK2 activity. The propositus and her mother had polyclonal myelopoiesis, ruling out another somatic mutation-derived clonal hematopoiesis. Some erythroid progenitors of all three generations grew without erythropoietin, a hallmark of PV. The in vitro reporter assay confirmed increased activity of the JAK2 kinase. Similar to PV, the JAK2 native cells have increased STAT5 phosphorylation, augmented transcripts of prothrombotic and inflammatory genes, and decreased KLF2 transcripts. The propositus was not controlled by hydroxyurea, and JAK2 inhibitors were not tolerated; however, Ropeginterferon-alfa-2b (Ropeg-IFN-α) induced a remission. Ropeg-IFN-α treatment also reduced JAK2 activity in the propositus, her mother and JAK2 PV subjects. We report dominantly inherited erythrocytosis secondary to a novel germline JAK2 gain-of-function mutation with many but not all comparable molecular features to JAK2 PV. We also document a previously unreported inhibitory mechanism of JAK2 signaling by Ropeg-IFN-α.
Topics: Adult; Female; Humans; Gain of Function Mutation; Germ-Line Mutation; Interferon-alpha; Janus Kinase 2; Pedigree; Polycythemia; Polycythemia Vera
PubMed: 38629639
DOI: 10.1002/ajh.27311 -
Stem Cell Reports May 2024Sepsis survivors exhibit immune dysfunction, hematological changes, and increased risk of infection. The long-term impacts of sepsis on hematopoiesis were analyzed using...
Sepsis survivors exhibit immune dysfunction, hematological changes, and increased risk of infection. The long-term impacts of sepsis on hematopoiesis were analyzed using a surgical model of murine sepsis, resulting in 50% survival. During acute disease, phenotypic hematopoietic stem and progenitor cells (HSPCs) were reduced in the bone marrow (BM), concomitant with increased myeloid colony-forming units and extramedullary hematopoiesis. Upon recovery, BM HSPCs were increased and exhibited normal function in the context of transplantation. To evaluate hematopoietic responses in sepsis survivors, we treated recovered sham and cecal ligation and puncture mice with a mobilizing regimen of granulocyte colony-stimulating factor (G-CSF) at day 20 post-surgery. Sepsis survivors failed to undergo emergency myelopoiesis and HSPC mobilization in response to G-CSF administration. G-CSF is produced in response to acute infection and injury to expedite the production of innate immune cells; therefore, our findings contribute to a new understanding of how sepsis predisposes to subsequent infection.
Topics: Animals; Sepsis; Granulocyte Colony-Stimulating Factor; Myelopoiesis; Mice; Hematopoietic Stem Cell Mobilization; Hematopoietic Stem Cells; Disease Models, Animal; Mice, Inbred C57BL; Male; Survivors
PubMed: 38608679
DOI: 10.1016/j.stemcr.2024.03.007 -
Blood Jun 2024Inflammatory responses must be tightly coordinated with the activation of emergency myelopoiesis to produce potent myeloid cells that fight infection without causing...
Inflammatory responses must be tightly coordinated with the activation of emergency myelopoiesis to produce potent myeloid cells that fight infection without causing excessive host damage. Here, we show that granulocyte-macrophage colony-stimulating factor (GM-CSF) programs myeloid-committed progenitors to produce trained macrophages (increased cytokine response), but programs the upstream noncommitted LKS+ progenitors (defined as Lin- c-Kit+ Sca-1+ cells) to produce tolerized macrophages (decreased cytokine response). In myeloid progenitors, GM-CSF strongly activates signal transducer and activator of transcription 5 (STAT5), Ras-Raf-extracellular signal regulated kinase (ERK), and Akt-mTOR signaling pathways, which are essential to establish a training program, whereas in LKS+ progenitors, GM-CSF induces NF-κB translocation to the nucleus to establish a tolerization program. These differences arise from higher GM-CSF receptor expression in myeloid progenitors compared with LKS+ cells. We demonstrate that β-catenin regulation of NF-κB nuclear translocation is central in this process. In myeloid progenitors, glycogen synthase kinase 3 (GSK3) inactivation by strong ERK and phosphatidylinositol 3 kinase (PI3K)-Akt signaling increases cytoplasmic β-catenin levels to block NF-κB nuclear translocation. In contrast, when ERK and PI3K-Akt signaling are weak, active GSK3 causes a decrease in β-catenin, allowing NF-κB nuclear translocation in LKS+ progenitors. Finally, GM-CSF-induced LKS+ tolerization takes place in several murine models of trained immunity and in human CD34+ CD38- progenitors. Our study reveals that in addition to activating myelopoiesis, GM-CSF also programs early and immediate myeloid progenitors to produce opposing immune memory phenotypes. We propose that the inflammatory response from immediate myeloid progenitors may be balanced by the tolerized phenotype of early progenitors, thus providing a mechanism for appropriate resolution of inflammation and protection against a prolonged cytokine storm.
Topics: Animals; Myelopoiesis; Receptors, Granulocyte-Macrophage Colony-Stimulating Factor; Mice; Granulocyte-Macrophage Colony-Stimulating Factor; Phenotype; Signal Transduction; NF-kappa B; Immunologic Memory; Mice, Inbred C57BL; Macrophages; Immunity, Innate; Myeloid Progenitor Cells; beta Catenin
PubMed: 38603633
DOI: 10.1182/blood.2024024330 -
Developmental and Comparative Immunology Jul 2024In the present study, using transgenic frogs that express GFP specifically in myeloid cells under the myeloperoxidase enhancer sequence, we found that...
In the present study, using transgenic frogs that express GFP specifically in myeloid cells under the myeloperoxidase enhancer sequence, we found that myeloperoxidase-positive cells are localized in the liver cortex at the late tadpole stages. Immunohistochemical analysis revealed that myelopoiesis in the liver cortex became evident after st. 50 and reached its peak by st. 56. Transplantation experiments indicated that cells with a high density at the liver cortex were derived from the dorso-lateral plate tissue in the neurula embryo. Analysis of smear samples of the cells isolated from collagenase-treated liver tissues of the transgenic tadpoles indicated that myeloid cells were the major population of blood cells in the larval liver and that, in addition to myeloid colonies, erythroid colonies expanded in entire liver after metamorphosis. Cells that were purified from the livers of transgenic tadpoles according to the GFP expression exhibited the multi-lobed nuclei. The results of present study provide evidence that the liver cortex of the Xenopus tadpole is a major site of granulopoiesis.
Topics: Animals; Xenopus laevis; Larva; Liver; Animals, Genetically Modified; Myeloid Cells; Myelopoiesis; Green Fluorescent Proteins; Peroxidase; Metamorphosis, Biological
PubMed: 38599553
DOI: 10.1016/j.dci.2024.105178 -
Frontiers in Oncology 2024Hematopoiesis is a tightly regulated process that produces all adult blood cells and immune cells from multipotent hematopoietic stem cells (HSCs). HSCs usually remain... (Review)
Review
Hematopoiesis is a tightly regulated process that produces all adult blood cells and immune cells from multipotent hematopoietic stem cells (HSCs). HSCs usually remain quiescent, and in the presence of external stimuli like infection or inflammation, they undergo division and differentiation as a compensatory mechanism. Normal hematopoiesis is impacted by systemic inflammation, which causes HSCs to transition from quiescence to emergency myelopoiesis. At the molecular level, inflammatory cytokine signaling molecules such as tumor necrosis factor (TNF), interferons, interleukins, and toll-like receptors can all cause HSCs to multiply directly. These cytokines actively encourage HSC activation, proliferation, and differentiation during inflammation, which results in the generation and activation of immune cells required to combat acute injury. The bone marrow niche provides numerous soluble and stromal cell signals, which are essential for maintaining normal homeostasis and output of the bone marrow cells. Inflammatory signals also impact this bone marrow microenvironment called the HSC niche to regulate the inflammatory-induced hematopoiesis. Continuous pro-inflammatory cytokine and chemokine activation can have detrimental effects on the hematopoietic system, which can lead to cancer development, HSC depletion, and bone marrow failure. Reactive oxygen species (ROS), which damage DNA and ultimately lead to the transformation of HSCs into cancerous cells, are produced due to chronic inflammation. The biological elements of the HSC niche produce pro-inflammatory cytokines that cause clonal growth and the development of leukemic stem cells (LSCs) in hematological malignancies. The processes underlying how inflammation affects hematological malignancies are still not fully understood. In this review, we emphasize the effects of inflammation on normal hematopoiesis, the part it plays in the development and progression of hematological malignancies, and potential therapeutic applications for targeting these pathways for therapy in hematological malignancies.
PubMed: 38571491
DOI: 10.3389/fonc.2024.1347402