Bone Marrow Hematopoietic Stem Cells Research Articles

PD-L1 blockade immunotherapy rewires cancer-induced emergency myelopoiesis.

Immune checkpoint blockade (ICB) immunotherapy has revolutionized cancer treatment, demonstrating exceptional clinical responses in a wide range of cancers. Despite the success, a significant proportion of patients still fail to respond, highlighting the existence of unappreciated mechanisms of immunotherapy resistance. Delineating such mechanisms is paramount to minimize immunotherapy failures and optimize the clinical benefit. In this study, we treated tumour-bearing mice with PD-L1 blockage antibody (aPD-L1) immunotherapy, to investigate its effects on cancer-induced emergency myelopoiesis, focusing on bone marrow (BM) hematopoietic stem and progenitor cells (HSPCs). We examined the impact of aPD-L1 treatment on HSPC quiescence, proliferation, transcriptomic profile, and functionality. Herein, we reveal that aPD-L1 in tumour-bearing mice targets the HSPCs in the BM, mediating their exit from quiescence and promoting their proliferation. Notably, disruption of the PDL1/PD1 axis induces transcriptomic reprogramming in HSPCs, observed in both individuals with Hodgkin lymphoma (HL) and tumour-bearing mice, shifting towards an inflammatory state. Furthermore, HSPCs from aPDL1-treated mice demonstrated resistance to cancer-induced emergency myelopoiesis, evidenced by a lower generation of MDSCs compared to control-treated mice. Our findings shed light on unrecognized mechanisms of action of ICB immunotherapy in cancer, which involves targeting of BM-driven HSPCs and reprogramming of cancer-induced emergency myelopoiesis.

2-AG-loaded and bone marrow-targeted PCL nanoparticles as nanoplatforms for hematopoietic cell line mobilization

BackgroundThe use of mobilizing agents for hematopoietic stem cell (HSC) transplantation is insufficient for an increasing number of patients. We previously reported lipid made endocannabinoid (eCB) ligands act on the human bone marrow (hBM) HSC migration in vitro, lacking long term stability to be therapeutic candidate. In this study, we hypothesized if a novel 2-AG-loaded polycaprolactone (PCL)-based nanoparticle delivery system that actively targets BM via phosphatidylserine (Ps) can be generated and validated.MethodsPCL nanoparticles were prepared by using the emulsion evaporation method and characterized by Zetasizer and scanning electron microscopy (SEM). The encapsulation efficiency and release profile of 2-AG were determined by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The presence of cannabinoid receptors (CBRs) in HSCs and monocytes was detected by flow cytometry. Cell morphology and viability were assessed using transmission electron microscopy (TEM), SEM, and the WST-1 viability assay. The migration efficacy of the 2-AG and 2-AG-loaded nanoparticle delivery system on HSCs and HPSCs (TF-1a and TF-1) and monocytes (THP-1) was evaluated using a transwell migration assay.ResultsThe 140–225 nm PCL nanoparticles exhibited an increasing polydispersity index (PDI) after the addition of Ps and 2-AG, with a surface charge ranging from − 25 to -50 mV. The nanoparticles released up to 36% of 2-AG within the first 8 h. The 2-AG-Ps-PCL did not affect cellular viability compared to control on days 5 and 10. The HSCs and monocytes expressed CB1R and CB2R and revealed increased migration to media containing 1 µM 2-AG-Ps-PCL compared to control. The migration rate of the HSCs toward monocytes incubated with 1 µM 2-AG-Ps-PCL was higher than that of the monocytes of control. The 2-AG-Ps-PCL formulation provided a real time mobilization efficacy at 1 µM dose and 8 h time window via a specific CBR agonism.ConclusionThe newly generated and validated 2-AG-loaded PCL nanoparticle delivery system can serve as a stable, long lasting, targeted mobilization agent for HSCs and as a candidate therapeutic to be included in HSC transplantation (HSCT) protocols following scale-up in vivo preclinical and subsequent clinical trials.Graphical

Mesenchymal stem cell infusion for enhancing hematopoietic recovery and addressing cytopenias in CAR-T cell therapy

BackgroundChimeric antigen receptor (CAR)-T therapy has emerged as a promising treatment for hematologic malignancies. However, cytopenia remains one of the most frequent and challenging adverse effects of this therapy.MethodsWe conducted a retrospective analysis of 26 patients with relapsed/refractory aggressive B-cell lymphoma who received CAR-T therapy at our center. Subsequently, to investigate measures to address cytopenias following CAR-T therapy, we isolated and generated murine CAR-T cells and bone marrow-derived mesenchymal stem cells (MSCs), establishing a murine syngeneic CAR-T therapy model. We assessed the impact of MSC infusion on hematopoietic recovery post-CAR-T therapy by evaluating complete blood count, bone marrow hematopoietic stem cells and their subpopulations, bone marrow histomorphology, and hematopoiesis-related genes.ResultsAll patients experienced cytopenias to varying degrees, with complete lineage involvement in half of the patients. Grade ≥ 3 cytopenias were observed in 88.46% of the patients. CAR-T therapy was associated with a higher incidence of biphasic, late-onset, or prolonged cytopenias. Survival analysis indicated that neutropenia and lymphopenia tended to be associated with better prognosis, whereas thrombocytopenia tended to be related to poorer outcomes. Through animal experiments, we discovered that MSCs infusion boosted HSCs and their long-term subpopulations, enhancing hematopoietic recovery, particularly in the megakaryocyte lineage, and mitigating bone marrow damage. Importantly, both in vitro and in vivo experiments demonstrated that MSCs did not compromise the activity or antitumor efficacy of CAR-T cells.ConclusionsOur findings propose MSCs infusion as a promising strategy to address cytopenias, particularly thrombocytopenia, after CAR-T therapy. This approach could help overcome certain limitations of cellular immunotherapy by enhancing hematopoietic recovery without compromising the efficacy of CAR-T cells.HighlightsCytopenia is a frequently observed adverse effect following CAR-T therapy, and it is often characterized by biphasic and prolonged patterns.MSCs play a critical role in promoting hematopoietic recovery and mitigating bone marrow damage in a murine model of CAR-T therapyThe activity and antitumor efficacy of CAR-T cells were not impaired by MSCs.Graphical

Hematopoietic stem cell heterogeneity and age-associated platelet bias are evolutionarily conserved.

Hematopoietic stem cells (HSCs) reconstitute multilineage human hematopoiesis after clinical bone marrow (BM) transplantation and are the cells of origin of some hematological malignancies. Although HSCs provide multilineage engraftment, individual murine HSCs are lineage biased and contribute unequally to blood cell lineages. Here, we performed high-throughput single-cell RNA sequencing in mice after xenograft with molecularly barcoded adult human BM HSCs. We demonstrated that human individual BM HSCs are also functionally and transcriptionally lineage biased. Specifically, we identified platelet-biased and multilineage human HSCs. Quantitative comparison of transcriptomes from single HSCs from young and aged BM showed that both the proportion of platelet-biased HSCs and their level of transcriptional platelet priming increase with age. Therefore, platelet-biased HSCs and their increased prevalence and transcriptional platelet priming during aging are conserved features of mammalian evolution.

Hematopoietic Growth Factors Regulate the Entry of Monocytes into the Adult Brain via Chemokine Receptor CCR5.

Monocytes are circulating macrophage precursors generated from bone marrow hematopoietic stem cells. In adults, monocytes continuously replenish cerebral border-associated macrophages under physiological conditions. Monocytes also rapidly infiltrate the brain in pathological settings. The mechanisms of recruiting monocyte-derived macrophages into the brain under pathological conditions have been extensively studied. However, it remains unclear how monocytes enter the brain to renew border-associated macrophages under physiological conditions. Using both in vitro and in vivo approaches, this study reveals that a combination of two hematopoietic growth factors, stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF), complementarily and synergistically enhances the adhesion of monocytes to cerebral endothelial cells in a dose-dependent manner. Cysteine-cysteine chemokine receptor 5 (CCR5) in brain endothelial cells, but not the cell adhesion molecules mediating neuroinflammation-related infiltration of monocyte-derived macrophages, modulates SCF+G-CSF-enhanced monocyte-endothelial cell adhesion. Blocking CCR5 or genetically deleting CCR5 reduces monocyte-endothelial cell adhesion induced by SCF+G-CSF. The SCF+G-CSF-enhanced recruitment of bone marrow-derived monocytes/macrophages into the cerebral perivascular space is also reduced in adult CCR5 knockout mice. This study demonstrates the role of SCF and G-CSF in regulating the entry of monocytes into the adult brain to replenish perivascular macrophages.

Burn Injury Results in Myeloid Priming during Emergency Hematopoiesis.

Hematopoiesis proceeds in a tiered pattern of differentiation, beginning with hematopoietic stem cells (HSC) and culminating in erythroid, myeloid, and lymphoid lineages. Pathologically altered lineage commitment can result in inadequate leukocyte production or dysfunctional cell lines. Drivers of emergency hematopoiesis after burn injury are inadequately defined. Burn injury induces a myeloid predominance associated with infection that worsens outcomes. This study aims to further profile bone marrow HSCs following burn injury in a murine model. C57BL/6 mice received burn or sham injury with ~12% total body surface area (TBSA) scald burn on the dorsal surface with subsequent sacrifice at 1, 2, 3, 7 and 10 days post-injury. Bone marrow (BM) from hindlimbs were analyzed for HSC populations via flow cytometry and analyzed using FlowJo Software (version 10.6). Event counts and frequencies were analyzed with multiple unpaired t-tests and linear mixed-effect regression. RT-PCR performed on isolated lineage negative BM cell RNA targeted PU.1, GATA-1, and GATA-3 with subsequent analysis conducted with QuantStudio 3 software. Statistical analysis and representation were performed on GraphPad software (Prism). Flow cytometry revealed significantly elevated proportions of Long-Term HSCs at 3 days post-injury (p < .05) and Short-Term HSCs at days 2, 3, and 10 (all p < .05) in burn-injured mice. There was a sustained, but not significant, increase in proportions in the multi-potent progenitor (MPP) 2 and 3 subpopulations in the burn cohort compared to sham controls. The common myeloid progenitor (CMP) proportion was significantly higher on days 3 and 10 (both p < .01), while the granulocyte-macrophage progenitor (GMP) proportion increased on days 1, 2, and 10 (p < .05, p < .01, p < .01). Although the megakaryocyte-erythrocyte progenitor (MEP) proportion appeared consistently lower in the burn cohort, this did not reach significance. mRNA analysis resulted in a downregulation of PU.1 on day 1 (p = 0.0002) with an upregulation by day 7 (p < 0.01). GATA-1 downregulation occurred by day 7 (p < 0.05), and GATA3 showed downregulation on days 3 and 7 (p < 0.05). Full-thickness burn results in an emergency hematopoiesis via proportional increase of Long Term-HSC and Short Term-HSC/MPP1 subpopulations beginning in the early post-injury period. Subsequent lineage commitment displays a myeloid predominance with a shift toward myeloid progenitors with mRNA analysis corroborating this finding with associated upregulation of PU.1 and downregulation of GATA-1 and GATA-3. Further studies are needed to understand how burn-induced emergency hematopoiesis may predispose to infection by pathologic lineage selection.

Glucose intolerance as a consequence of hematopoietic stem cell dysfunction in offspring of obese mice

ObjectiveMaternal obesity is increasingly common and negatively impacts offspring health. Children of mothers with obesity are at higher risk of developing diseases linked to hematopoietic system abnormalities and metabolism such as type 2 diabetes. Interestingly, disease risks are often dependent on the offspring's sex, suggesting sex-specific reprogramming effect of maternal obesity on offspring hematopoietic stem and progenitor cell (HSPC) function. However, the impact of maternal obesity exposure on offspring HSPC function, and the capability of HSPC to regulate offspring metabolic health is largely understudied. This study aims to test the hypothesis that offspring of obese mice exhibit sex-differences in HSPC function that affect offspring's metabolic health. MethodsWe first assessed bone marrow hematopoietic stem and progenitor cell phenotype using postnatal day 21 (P21) and 8-week-old C57BL/6J mice born to control and diet-induced obese dams. We also sorted HSPC (Lineage-, Sca1+, cKit + cells) from P21 mice for competitive primary and secondary transplant, as well as transcriptomic analysis. Body weight, adiposity, insulin tolerance test and glucose tolerance tests were performed in primary and secondary transplant recipient animals. ResultsWe discovered sex-differences in offspring HSPC function in response to maternal obesity exposure, where male offspring of obese dams (MatOb) showed decreased HSPC numbers and engraftment, while female MatOb offspring remained largely unaffected. RNA-seq revealed immune stimulatory pathways in female MatOb offspring. Finally, only recipients of male MatOb offspring HSPC exhibited glucose intolerance. ConclusionsThis study demonstrated the lasting effect of maternal obesity exposure on offspring HSPC function and implicates HSPC in metabolic regulation.

Therapeutic Effect of Stem Cells from Different Sources on Diabetic Foot Ulcers: Systematic Review and Network Meta-Analysis.

To evaluate the efficacy of stem cell therapy from different sources on the ankle-brachial index, wound closure percentage, and wound closure time in the treatment of diabetic foot ulcers (DFUs). A literature search was conducted in PubMed, Embase, Cochrane Library's Central Register of Controlled Trials, and Web of Science, extending through June 29, 2023. Quality evaluation was done using the Cochrane's bias risk assessment tool (RoB 2.0). Employing a Bayesian approach, the statistical computations was executed with the JAGS software, leveraging the gemtc 0.8-2 and rjags 4-10 libraries, within the R environment 4.1.2. The included interventions came from peripheral blood, bone marrow, placenta, umbilical cord blood, adipose tissue, or others. A preliminary search identified 2286 articles, of which 23 randomized controlled trials met the inclusion criteria and were ultimately included. The analysis findings indicated that mesenchymal stem cells derived from the umbilical cord (HUCMSCs) led to a notable enhanced the ankle-brachial index in patients with DFUs compared to standard treatment (MD: 0.2; 95% CI [0.01, 0.36]). HUCMSCs were found to be the optimal therapeutic approach for enhancing the ankle-brachial index (SUCRA = 82.7%). Research on the wound closure percentage revealed that compared to platelet-rich plasma (PRP), processed microvascular tissue (PMVT), peripheral blood stem cells (PBSCs), microfragmented adipose tissue (MFAT), autologous bone marrow-derived stem cell therapy (ABMSCT), adipose-derived stem cells (ASCs), and dehydrated human umbilical cord allograft (EpiCord), Huoxue Shengji Decoction (HXSJD) + ABMSCT (H_Group_hematopoietic) significantly increased the wound closure percentage in DFU patients (P < 0.05). According to the SUCRA ranking, HXSJD + ABMSCT was the best therapeutic method to increase the percentage of wound closure (SUCRA = 93.8%). This study employed a network meta-analysis method, combining direct and indirect comparisons, to analyze the latest clinical data and concluded that umbilical cord mesenchymal stem cells and the combination of HXSJD + autologous bone marrow hematopoietic stem cell treatment as adjunctive therapies for DFUs may have beneficial effects. Future research needs to focus on this.

Bone marrow niches for hematopoietic stem cells.

Hematopoietic stem cells (HSCs) are the cornerstone of the hematopoietic system. HSCs sustain the continuous generation of mature blood derivatives while self-renewing to preserve a relatively constant pool of progenitors throughout life. Yet, long-term maintenance of functional HSCs exclusively takes place in association with their native tissue microenvironment of the bone marrow (BM). HSCs have been long proposed to reside in fixed and identifiable anatomical units found in the complex BM tissue landscape, which control their identity and fate in a deterministic manner. In the last decades, tremendous progress has been made in the dissection of the cellular and molecular fabric of the BM, the structural organization governing tissue function, and the plethora of interactions established by HSCs. Nonetheless, a holistic model of the mechanisms controlling HSC regulation in their niche is lacking to date. Here, we provide an overview of our current understanding of BM anatomy, HSC localization, and crosstalk within local cellular neighborhoods in murine and human tissues, and highlight fundamental open questions on how HSCs functionally integrate in the BM microenvironment.

Biomarkers for Radiation Biodosimetry and Correlation with Hematopoietic Injury in a Humanized Mouse Model.

After a large-scale radiological or nuclear event, hundreds of thousands of people may be exposed to ionizing radiation and require subsequent medical management. Acute exposure to moderate doses (2-6 Gy) of radiation can lead to the hematopoietic acute radiation syndrome, in which the bone marrow (BM) is severely compromised, and severe hemorrhage and infection are common. Previously, we have developed a panel of intracellular protein markers (FDXR, ACTN1, DDB2, BAX, p53 and TSPYL2), designed to reconstruct absorbed radiation dose from human peripheral blood (PB) leukocyte samples in humanized mice up to 3 days after exposure. The objective of this work was to continue to use the humanized mouse model to evaluate biomarker dose-/time- kinetics in human PB leukocytes invivo, at an earlier (day 2) and later (day 7) time point, after exposure to total-body irradiation (TBI) doses of 0 to 2 Gy of X rays. In addition, to assess hematological sensitivity and radiation-induced injury, PB leukocyte cell counts, human BM hematopoietic stem cell (HSC) and progenitor cell [multipotent progenitor (MPP), common myeloid progenitor (CMP), granulocyte myeloid progenitor (GMP), megakaryocyte/erythrocyte progenitor (MEP) and multi-lymphoid progenitor (MLP)] levels were measured, and their correlation was also examined as the BM damages are difficult to assess by routine tests. Peripheral blood B-cells were significantly lower after TBI doses of 0.5 Gy on day 2 and 2 Gy on days 2 and 7; T-cells were significantly reduced only on day 2 after 2 Gy TBI. Bone marrow HSCs and MPP cells showed a dose-dependent depletion after irradiation with 0.5 Gy and 2 Gy on day 2, and after 1 Gy and 2 Gy on day 7. Circulating B cells correlated with HSCs, MPP and MLP cells on day 2, whereas T cells correlated with MPP, and myeloid cells correlated with MLP cells. On day 7, B cells correlated with MPP, CMP, GMP and MEP, while myeloid cells correlated with CMP, GMP and MEP. The intracellular leukocyte biomarkers were able to discriminate unirradiated and irradiated samples at different time points calculated by receiver operating characteristic (ROC) curve. Using machine learning algorithm methods, combining ACTN1, p53, TSPYL2 and PB-T cell and PB-B cell counts served as a strong predictor (area under the ROC >0.8) to distinguish unirradiated and irradiated samples independent of the days after TBI. The results further validated our biomarker-based triage assay and additionally evaluated the radiation sensitivity of the hematopoietic system after TBI exposures.

Mobilization dynamics of bone marrow hematopoietic stem cells during hematopoietic regeneration

Under stress hematopoiesis, previous studies have suggested the migration of hematopoietic stem cells (HSCs) from bone marrow (BM) to extramedullary sites such as the spleen. However, there is little direct evidence of HSC migration from the BM to the spleen. Here, we induced myeloablation via 5-fluorouracil (5-FU) and showed direct evidence of HSC migration from BM to spleen during hematopoietic regeneration via a photoconvertible fluorophore. Moreover, during steady state, HSCs preferentially migrated to BM rather than spleen, but during hematopoietic regeneration, HSCs preferred spleen as a migration site equivalently or greater. Furthermore, in the early phase, HSCs egressed from BM through the attenuated HSC retention. However, HSCs in the late phase gained significantly enhanced cell-autonomous motility, which was independent of chemotaxis. Collectively, HSC mobilization from BM, before the migration to the spleen, was dynamically changed from passive to active events during hematopoietic regeneration.

In Fanconi anemia, impaired accumulation of bone marrow neutrophils during emergency granulopoiesis induces hematopoietic stem cell stress

Fanconi Anemia (FA) is an inherited disorder of DNA-repair due to mutation in one of 20+ interrelated genes that repair intra-strand DNA crosslinks and rescue collapsed or stalled replication forks. The most common hematologic abnormality in FA is anemia, but progression to bone marrow failure (BMF), clonal hematopoiesis, or acute myeloid leukemia (AML) may also occur. In prior studies, we found that Fanconi DNA-repair is required for successful emergency granulopoiesis; the process for rapid neutrophil production during the innate immune response. Specifically, Fancc-/- mice did not develop neutrophilia in response to emergency granulopoiesis stimuli, but instead exhibited apoptosis of bone marrow hematopoietic stem cells (HSCs) and differentiating neutrophils. Repeated emergency granulopoiesis challenges induced BMF in most Fancc-/- mice, with AML in survivors. In contrast, we found equivalent neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice and wild type (WT) mice, without BMF. Since termination of emergency granulopoiesis is triggered by accumulation of bone marrow neutrophils, we hypothesize neutrophilia protects Fancc-/-Tp53+/- bone marrow from the stress of a sustained inflammation that is experienced by Fancc-/- mice. In the current work, we found that blocking neutrophil accumulation during emergency granulopoiesis led to BMF in Fancc-/-Tp53+/- mice, consistent with this hypothesis. Blocking neutrophilia during emergency granulopoiesis in Fancc-/-Tp53+/- mice (but not WT) impaired cell cycle checkpoint activity, also found in Fancc-/- mice. Mechanisms for loss of cell cycle checkpoints during infections challenges may define molecular markers of FA progression, or suggest therapeutic targets for bone marrow protection in this disorder.

Decoding human bone marrow hematopoietic stem and progenitor cells from fetal to birth

Bone marrow (BM) is the dominant site of hematopoiesis after 20 post-conception weeks (PCWs), but the intricacies of hematopoietic development in fetal BM up to birth and its involvement in malignancies remain unknown. Here, we compared the single-cell transcriptomic profile of BM hematopoietic stem and progenitor cells (HSPCs) at the early (12-14 PCW), middle (19-22 PCW) second trimester, and the neonatal stage. The stemness of hematopoietic stem cell and multipotent progenitor (HSC/MPP) is established at the middle second trimester, then maintained until birth. Furthermore, differentiation potentials toward three lineages are enhanced after the middle second trimester for birth, accompanied by the upregulation of aerobic metabolism. Notably, decreased stemness in HSCs/MPPs and higher interferon signals in progenitors at the early second trimester rendered the HSPCs more proximal to leukemogenesis. Collectively, our work elucidated the dynamics of fetal hematopoiesis in preparation for birth, offering valuable insights into the pathological processes underlying leukemia.

ZMAT3 participated in benzene-caused disruption in self-renewal and differentiation of hematopoietic stem cells via TNF-α/NF-κB pathway

Benzene is a common environmental and occupational pollutant, benzene exposure causes damage to hematopoietic system. ZMAT3 is a zinc finger protein which has important biological functions. In this study, benzene-exposed mouse model and ZMAT3 overexpression and low expression hematopoietic stem cells (HSCs) models were constructed to explore the mechanism of ZMAT3 in benzene-induced hematopoietic toxicity. The results showed that benzene increased the expression of ZMAT3 in mouse bone marrow (BM) cells, HSCs and peripheral blood (PB) leukocyte, and the changes in HSCs were more sensitive than BM and PB cells. In addition, overexpression of ZMAT3 decreased the self-renewal ability of HSCs and reduced the HSCs differentiation into myeloid hematopoietic cells, while low expression has the opposite effect. Besides, over and low expression of ZMAT3 both increased the HSCs differentiation into lymphoid progenitor cells. Moreover, bioinformatics analysis suggested that ZMAT3 was associated with TNF-α signaling pathway, and the correlation was confirmed in mouse model. Meanwhile, the results indicated that ZMAT3 promoted TNF-α mRNA processing by binding to the ARE structural domain on TNF-α and interacting with hnRNP A2/B1 and hnRNP A1 proteins, ultimately activating the NF-κB signaling pathway. This study provides a new mechanism for the study of benzene toxicity.

Hematopoietic Stem Cells and Their Niche in Bone Marrow.

Extensive research has explored the functional correlation between stem cells and progenitor cells, particularly in blood. Hematopoietic stem cells (HSCs) can self-renew and regenerate tissues within the bone marrow, while stromal cells regulate tissue function. Recent studies have validated the role of mammalian stem cells within specific environments, providing initial empirical proof of this functional phenomenon. The interaction between bone and blood has always been vital to the function of the human body. It was initially proposed that during evolution, mammalian stem cells formed a complex relationship with the surrounding microenvironment, known as the niche. Researchers are currently debating the significance of molecular-level data to identify individual stromal cell types due to incomplete stromal cell mapping. Obtaining these data can help determine the specific activities of HSCs in bone marrow. This review summarizes key topics from previous studies on HSCs and their environment, discussing current and developing concepts related to HSCs and their niche in the bone marrow.

Autoantibodies-Abzymes with Amylase Activity in Experimental Autoimmune Encephalomyelitis Mice

The exact mechanisms of multiple sclerosis evolution are still unknown. However, the progress in C57BL/6 mice of experimental autoimmune encephalomyelitis (EAE, similar to human multiple sclerosis) happens as a result of the contravention of bone marrow hematopoietic stem cells differentiation profiles integrated with the production of toxic for human’s auto-antibodies-abzymes splitting myelin basic protein (MBP), myelin oligodendrocyte glycoprotein (MOG), histones, DNA and RNA as well as IgGs with catalase and peroxidase activities. Here, we first analyzed the change in the relative amylase activity of IgGs from C57BL/6 mice blood over time at different stages of the EAE evolution: onset, acute, and remission phases. It was shown that the amylase activity of IgGs during spontaneous development of EAE first noticeably increases from 50 to 80, then sharply decreases to 100-130, and again sharply increases to 150 days of mice life. Immunization of 3-month-old mice (time zero) with the DNA-histone complex leads to a decrease, while their treatment with MOG results in a substantial increase in the amylase activity of IgGs. The relative activities of all IgG-abzymes indicated above corresponding to various stages of EAE development were compared. The data shows that spontaneous EAE and immunization of mice with DNAhistones complex and MOG leads to a different and very expanded formation of various B lymphocytes, producing abzymes with several diverse catalytic activities. In addition, the relative number of lymphocytes producing diverse antibodies with distinct enzymatic activities (including their relative activities) significantly depend both on the stages of spontaneous and antigen-induced accelerations of EAE development.

Screening and Activity Evaluation of Novel BCR-ABL/T315I Tyrosine Kinase Inhibitors.

Chronic myeloid leukemia (CML) is a kind of malignant tumor formed by the clonal proliferation of bone marrow hematopoietic stem cells. BCR-ABL fusion protein, found in more than 90% of patients, is a vital target for discovering anti- CML drugs. Up to date, imatinib is the first BCR-ABL tyrosine kinase inhibitor (TKI) approved by the FDA for treating CML. However, the drug resistance problems appeared for many reasons, especially the T135I mutation, a "gatekeeper" of BCR-ABL. Currently, there is no long-term effective and low side effect drug in clinical. This study intends to find novel TKIs targeting BCR-ABL with high inhibitory activity against T315I mutant protein by combining artificial intelligence technology and cell growth curve, cytotoxicity, flow cytometry and Western blot experiments. The obtained compound was found to kill leukemia cells, which had good inhibitory efficacy in BaF3/T315I cells. Compound no 4 could induce cell cycle arrest, cause autophagy and apoptosis, and inhibit the phosphorylation of BCR-ABL tyrosine kinase, STAT5 and Crkl proteins. The results indicated that the screened compound could be used as a lead compound for further research to discover ideal chronic myeloid leukemia therapeutic drugs.

Bone-marrow-homing lipid nanoparticles for genome editing in diseased and malignant haematopoietic stem cells.

Therapeutic genome editing of haematopoietic stem cells (HSCs) would provide long-lasting treatments for multiple diseases. However, the in vivo delivery of genetic medicines to HSCs remains challenging, especially in diseased and malignant settings. Here we report on a series of bone-marrow-homing lipid nanoparticles that deliver mRNA to a broad group of at least 14 unique cell types in the bone marrow, including healthy and diseased HSCs, leukaemic stem cells, B cells, T cells, macrophages and leukaemia cells. CRISPR/Cas and base editing is achieved in a mouse model expressing human sickle cell disease phenotypes for potential foetal haemoglobin reactivation and conversion from sickle to non-sickle alleles. Bone-marrow-homing lipid nanoparticles were also able to achieve Cre-recombinase-mediated genetic deletion in bone-marrow-engrafted leukaemic stem cells and leukaemia cells. We show evidence that diverse cell types in the bone marrow niche can be edited using bone-marrow-homing lipid nanoparticles.

Epigenetic drug screen of natural killer cells identified compounds controlling immune training and tolerance

Abstract Natural killer (NK) cells are cytotoxic innate lymphocytes that provide defense against pathogens and malignancy. New evidence identified that NK cells are capable of memory-like immune responses in certain settings. This innate immune memory is thought to be imprinted through epigenetic modifications. However, precise epigenic pathways or strategies to modulate long-term NK cell activity are not well defined. In this study, we performed a screen of an epigenetic library containing 160 drug compounds with well-characterized epigenetic regulatory mechanisms, to identify drugs and pathways that could train or tolerize NK cell activation. One compound that we identified was the H3K27 methyltransferase Ezh2, which regulated NK cell lineage commitment from bone marrow hematopoietic stem cells and altered the phenotype of differentiated NK cells to increased cytotoxicity. This outcome provides an option to train or induce stronger cytotoxic effects on NK cells. In contrast, another compound we identified was the histone deacetylase inhibitor, Givinostat, which did not alter NK cell commitment from bone marrow stem cells, but significantly decreased NK cell function in the periphery resulting in a more tolerant innate immune state to secondary NK cell stimulation. Identification and exploration of these epigenome altering drugs may offer further insight into downstream pathways of NK cell function or provide novel therapies for tolerizing or priming innate immune responses.

The malignant transformation potential of the oncogene STYK1/NOK at early lymphocyte development in transgenic mice

B-cell Chronic Lymphocytic Leukemia (B-CLL) is a malignancy caused by the clonal expansion of mature B lymphocytes bearing a CD5+CD19+ (B1) phenotype. However, the origin of B-CLL remains controversial. We showed previously that STYK1/NOK transgenic mice develop a CLL-like disease. Using this model system in this study, we attempt to define the stage of CLL initiation. Here, we show that the phenotype of STYK1/NOK-induced B-CLL is heterogeneous. The expanded B1 lymphocyte pool was detected within peripheral lymphoid organs and was frequently associated with the expansions of memory B cells. Despite this immunophenotypic heterogeneity, suppression of B cell development at an early stage consistently occurred within the bone marrow (BM) of STYK1/NOK-tg mice. Overall, we suggest that enforced expression of STYK1/NOK in transgenic mice might significantly predispose BM hematopoietic stem cells (HSCs) towards the development of B-CLL.