Extracellular vesicles (EV) represent a conserved and highly efficient mechanism for cell-to-cell communication. Matrix-bound nanovesicles (MBV) are a recently identified type of EV embedded within the extracellular matrix with potent local and systemic immunomodulatory effects on myeloid cells. These effects are durable and last beyond the predicted life span of differentiated myeloid cells such as macrophages. The present study investigated MBV-directed epigenetic modification in myeloid precursors as a potential explanation for their prolonged immunomodulatory effects. Flow cytometry and ATAC sequencing studies show that MBV are internalized by myeloid cell progenitors in the bone marrow and in macrophages after terminal differentiation. This internalization is coincident with epigenetic changes that are associated with modulation of macrophage responses to inflammatory stimuli. Furthermore, MBV treatment differentially alters chromatin accessibility as a function of cell differentiation state (i.e., myeloid progenitor versus macrophage). The present study shows the epigenetic effects of MBV on myeloid cells, representing a potential avenue to exploit the therapeutic potential of biologic scaffold materials.

Integrative multi-omics analysis of long non-coding RNA regulatory networks in chronic myeloid leukemia resistance and leukemic stem cell persistence.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of cells composed of myeloid progenitor cells, immature granulocytes, monocytes, and dendritic cells. These cells were initially discovered in cancer research and have been confirmed to show immunosuppressive functions. In recent years, their role in autoimmune diseases has attracted more attention. Multiple sclerosis (MS) is a rare autoimmune disease of the central nervous system, which can lead to non-traumatic disability among young adults. However, the exact pathogenesis is still unclear, and there is no therapy to cure MS. Studies have shown that MDSCs can play an important immunomodulatory role in MS and experimental autoimmune encephalomyelitis (EAE) model through multiple pathways. This article reviews the origin and characteristics of MDSCs and their role in MS/EAE, with the aim of proposing new strategies for investigating the pathogenesis and treatment of MS.

Flow cytometry (FCM) is a co-criterion in myelodysplastic neoplasms (MDS) diagnostics, currently not used for prognostication. This study aimed to develop an FCM-score predicting overall survival (OS) in MDS to improve early clinical patient prognostication. FCM of bone marrow samples was performed for diagnostic purposes in 509 therapy-naïve MDS patients and 77 healthy donors. The following methodology was used: (1) uni- and multivariate Cox proportional hazards regression and Kaplan-Meier curves for OS to assess FCM-parameters' prognostic value; (2) receiver operating characteristic (ROC) curves to test the prognostic superiority of FCM-parameters versus established FCM-scores and clinical risk-scores; and (3) development of a FCM-prognostic score (FCM-PS) based on six FCM-parameters with independent prognostic impact. The final FCM-PS included aberrancies of progenitor cells (increased CD45 mean fluorescence intensity [MFI]-ratio of lymphocytes and myeloid progenitor cells, decreased % of lymphatic progenitor cells), granulopoiesis (increased CD33 MFI, decreased sideward scatter [SSC]-ratio of granulopoiesis and lymphocytes), lymphocytes (increased % of B-lymphocytes), and plasmacytoid dendritic cells (increased %). FCM-PS outperformed established scores for OS (hazard ratio [HR] 4.08 [95% CI 2.54-6.55] vs. Ogata-score: 2.44 [1.61-3.70], International Prognostic Scoring System-Revised [IPSS-R]: 2.37 [1.61-3.49], International Prognostic Scoring System-Molecular [IPSS-M]: 0.816 [0.303-2.196]). Patients in the FCM-PS low score category showed significantly better OS (P < 0.0001). Further, FCM-PS allowed discrimination within IPSS-R area under the curve [AUC]: 0.70 vs. 0.62) and IPSS-M (AUC: 0.75 vs. 0.48) subgroups. Validation of the prognostic FCM-PS in an independent patient cohort confirmed good discrimination performance (AUC: 0.70). We introduce a unique, easy-to-use prognostic FCM-PS score (panel: CD45/CD34/CD117/CD33/CD19/CD123/HLA-DR) for OS in MDS, allowing refined risk stratification for IPSS-R subgroups.

Aging is a dominant risk factor for chronic diseases characterized by the functional decline of tissues and organs. During aging, the hematopoietic system declines in regenerative capacity-seemingly attributable to increases in DNA damage, replicative stress, and autophagic flux-resulting in skewing towards a myeloid lineage and away from a lymphoid lineage. Here, we characterized the transcriptomic and cellular landscape of the aged C57Bl/6J mouse hematopoietic system using a combination of bulk RNAseq and single cell RNAseq (scRNAseq). We show that aging leads to global transcriptional alterations in bulk peripheral blood mononuclear cells (PBMCs), lineage marker-depleted bone marrow cells (Lin-BM), and in hematopoietic stem and progenitor cells (HSPCs), immunophenotypically lineage marker negative (Lin-) Sca1+ cKit+ (LSK+). These changes indicate widespread activation of inflammatory processes, namely in PBMCs and Lin-BM cells. Interestingly, there is also a downregulation of cell cycle genes in HSPCs during aging. ScRNAseq across 39 hematopoietic cell types revealed age-related skewing in cell composition. Aged PBMCs showed significant decreases in CD4 and CD8 naïve cells concomitant with increases in CD4/8 memory and CD8 exhausted T cell populations. Lin-BM cells showed significant myeloid skewing in common myeloid progenitor (CMP) cells, as well as in the HSC population. We also identified a unique HSC population marked by increased Vwf, Wwtr1, and Clca3a1 expression that does not exist in young HSCs, thus likely marking true aged HSCs. Collectively, this work should serve as a useful resource for understanding and therapeutically targeting the aged hematopoietic system.

BackgroundAcute myeloid leukemia (AML) is a malignant disorder originating from myeloid hematopoietic stem and progenitor cells. Despite the availability of current treatment options, a significant number of patients fail to achieve complete remission after initial chemotherapy. CD33, a transmembrane protein highly expressed on AML cells, serves as a promising therapeutic target. This study aimed to develop and evaluate chimeric antigen receptor T cells (CAR-T) and antibody-drug conjugates (ADC) based on humanized antibodies, specifically targeting CD33, to assess their potential efficacy against AML.MethodsMonoclonal antibodies specific to human CD33 were generated by immunizing mice and then humanized. These humanized antibodies were then used to construct CAR-T cells and ADCs, and their cytotoxic properties were evaluated both in vitro and in vivo. In the in vivo experiments, mice bearing Molm13-Luciferase tumor cells were assigned to different treatment groups and were administered with saline, Gemtuzumab-MMAE, or Clone3HM-MMAE.ResultsThe in vitro experiments revealed that several antibody clones, including Clone2HM, Clone3HM, Clone5HM, Clone6HM, and Clone7HM, displayed strong cytotoxic effects against Molm13-Luciferase tumor cells when conjugated with MMAE, outperforming the positive control antibody Gemtuzumab-MMAE. In the in vivo studies, mice treated with Clone3HM-MMAE showed a significant reduction in tumor signals, which nearly disappeared in the latter stages of the experiment. This led to a substantially longer survival time compared to other groups. Additionally, the body weight of mice in all treatment groups remained stable throughout the treatment period, indicating a favorable safety profile.ConclusionThe CAR-T cells and ADCs developed in this study, based on humanized antibodies, showed significant anti-tumor efficacy in the AML model. Clone3HM-MMAE, in particular, demonstrated excellent anti-tumor activity along with a strong safety profile. These results strongly support the further development of targeted therapeutic strategies for AML.

BackgroundThe genes controlling lineage determination and differentiation tend to be essential for the development of acute myeloid leukemia (AML). Identifying novel target genes capable of promoting the differentiation and maturation of undifferentiated leukemia cells offers a promising therapeutic strategy for the treatment of AML.MethodsWe used conditional Elk1 and KrasG12D expression mice, along with Mx1-Cre, Lyz2-Cre and Elane-Cre drive strains (which enable stage specific control of Elk1 or KrasG12D expression), to investigate the function of Elk1 in the hematopoiesis and leukemogenesis. Bone marrow transplantation assay was performed to explore the function of Elk1 in hematopoiesis under stress conditions. Additionally, bulk-cell RNA sequencing, single-cell RNA sequencing and proteomics were performed to reveal the signaling pathways altered by Elk1. Finally, undifferentiated leukemia cells were used to verify whether inhibiting ELK1 could promote the differentiation of these cells into mature neutrophils.ResultsELK1 is highly expressed in undifferentiated AML cells. Studies using mouse model demonstrated that overexpression of Elk1 accelerates the development of KrasG12D-induced myeloid leukemia by impairing the stemness of hematopoietic stem cells (HSCs) and impeding the differentiation of neutrophils. Furthermore, impeding the maturation of neutrophils independently promotes the development of KrasG12D mutation-induced myeloid leukemia. Meanwhile, our in vitro experiments preliminarily confirmed that inhibiting ELK1 suppresses the proliferation of leukemia cells and induces the differentiation of CD15+CD66b- myeloid progenitor cells into CD15+CD66b+ neutrophils.ConclusionsOur study demonstrates that ELK1 is a potential therapeutic target for AML, due to its critical role in regulating neutrophils differentiation.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40164-025-00742-4.

Single-Cell Profiling of ANKRD26 Thrombocytopenia Reveals Progenitor Expansion and Polyploid Apoptosis via JUNB-p21.

The glycosaminoglycan oncofetal chondroitin sulfate represents a novel target for antibody drug-conjugate therapy for AML.

The contribution of chemotherapy-induced tissue injury to individual susceptibility to metastasis remains largely unexplored. We report that chemotherapy indirectly prevents colorectal cancer (CRC) liver metastases by inducing a lasting systemic “chemomemory”. Chemotherapy-induced intestinal mucositis alters nutrient availability, promoting the expansion of tryptophan-metabolizing bacteria and production of the microbial metabolite indole-3-propionic acid (IPA). IPA reprograms bone marrow myelopoiesis by redirecting common myeloid progenitor fate toward the macrophage lineage, limiting generation of immunosuppressive Ly6ChighCCR2+ monocytes. This shift enhances CD4+ T cell antitumor function by promoting Th1 differentiation and spatially reorganizing CD8+ and CD4+ T cell interactions within the metastatic microenvironment. In a subset of CRC patients, circulating IPA levels increase after chemotherapy and inversely correlate with monocyte abundance, while high monocyte levels were associated with reduced survival. Our findings reveal that chemotherapy-induced intestinal injury normalizes pathological myelopoiesis through a microbiota-derived metabolite and identify IPA as a potential adjuvant to counteract monocyte-driven immunosuppression and metastasis.

Acute myeloid leukemia (AML) is a hematologic malignancy characterized by the malignant proliferation of myeloid progenitor cells. Although the introduction of the B-cell lymphoma-2 (BCL-2) inhibitor Venetoclax (VEN) has significantly improved patient outcomes and established it as a first-line treatment, high rates of drug resistance and relapse remain major clinical challenges. We integrated RUNX3 chromatin immunoprecipitation sequencing (ChIP-seq) data with the GAPIA2 database to identify CRTC2 as a key candidate gene. Subsequently, we employed qRT-PCR to compare CRTC2 expression levels between donors and AML patients. The role of CRTC2 in apoptosis was further validated through knockdown and overexpression experiments in various cell lines. To investigate the impact of CRTC2 on AML progression, we established a cell line-derived xenograft (CDX) model. The proportion of human CD45-positive (hCD45+) cells in the bone marrow and liver was assessed, and histological examination was conducted using HE staining, along with peripheral blood smear analysis. In addressing VEN resistance, we analyzed CRTC2 expression patterns in clinical samples and explored the synergistic therapeutic effect of a CRTC2 inhibitor in combination with VEN. To further elucidate the underlying molecular mechanisms, we performed mitochondrial function assays and analyzed mitochondrial translation-related proteins. Clinical analyses have demonstrated that elevated expression levels of CRTC2, a downstream target of RUNX3, are significantly correlated with poor prognosis in patients with AML. Functional experiments have shown that CRTC2 plays a role in disease progression by modulating apoptosis in AML cells. The knockdown of CRTC2 was observed to delay disease progression in CDX mouse models. Additional investigations revealed a positive correlation between CRTC2 expression and resistance to VEN in AML cells, with CRTC2 inhibition synergistically enhancing VEN's cytotoxic effects. Mechanistic studies suggest that increased mitochondrial activity contributes to VEN resistance, thereby identifying a potential molecular target for overcoming drug resistance. CRTC2 is a key regulator in AML, with high expression levels promoting disease progression and resistance to VEN. Inhibiting CRTC2 reduces mitochondrial translation and energy reserves, increasing AML cell sensitivity to VEN. These results highlight CRTC2 as a promising therapeutic target and suggest a new strategy to overcome VEN resistance.

Tumor necrosis factor from leukemic environment stimulates hematopoietic stem/progenitor cells toward megakaryocyte/myeloid lineage bias.

ABSTRACTMyeloid progenitor cell (MPC) therapy can protect against infection and can be used as an irradiation countermeasure, but can also prevent rejection of matched grafts. Here we report on the matching requirements between MPCs and skin grafts, and on the development of a non-lethal preconditioning model that supports MPC-induced protection of skin grafts. Mouse MPCs (mMPC) were obtained from HSC following 10-dayex vivoexpansion. Skin grafts were tested in host mice that either received a lethal dose of irradiation and reconstitution with allogeneic mMPC and third party HSCs or were given injections with depleting antibodies and chemotherapeutics followed by transplantation of mMPC without HSC. mMPC-matched grafts were protected and no significant difference was observed between mice receiving irradiation and fully matched grafts (major and minor transplantation antigens), partially matched grafts (major only), and fully matched grafts in mice that received sublethal irradiation. Haploidentical grafts (half of the MHC alleles not matched at all) are not protected. We conclude that closely matched mMPCs are sufficient to prevent rejection. We also show that mMPCs are effective in a trachea transplant model. Graft protection does not require either lethal preconditioning or an accompanying HSC transplantation, and affects both T- and B-cell responses.

Rationale:Myeloid sarcoma (MS) is an extramedullary solid tumor composed of myeloid progenitor cells, which is rare in non-leukemic patients. Our research aims to enhance the understanding of the challenges in diagnostic and therapeutic of MS.Patient concerns:A 61-year-old male was admitted to hospital presenting with “malignant pleural tumor diagnosed 2 months prior, accompanied by chest distress for over a month.”Diagnosis:Cytological analysis of pleural effusion confirmed malignant cells and supported by immunohistochemical results. Bone marrow biopsy showed 83.5% blasts, with flow cytometry indicating 56.32% tumor cells and the presence of the AML1–ETO fusion gene (FLT3−ITD+). Cytogenetic analysis revealed complex karyotypic abnormalities.Interventions and outcomes:After treated with the Idarubicin-Cytarabine regimen and intrapleural cisplatin, bone marrow biopsy revealed residual tumor cells (0.46%). Further consolidation with the Idarubicin-Cytarabine regimen and additional cycles of azacitidine plus venetoclax and cytarabine plus venetoclax were administered. Unfortunately, the patient passed away following disease progression.Lessons:Although pleural myeloid sarcoma is extremely rare, it must be included in the differential diagnosis for unexplained solid pleural masses, particularly when accompanied by pleural effusion. Upon diagnosis, comprehensive staging investigations, including bone marrow biopsy and flow cytometry, must be performed immediately. The successful management of such complex cases relies on the close collaboration of a multidisciplinary team, including radiologists, pathologists, hematologists, and thoracic surgeons. Radiologists identify atypical imaging features, pathologists confirm the diagnosis through precise immunophenotyping, and ultimately, hematologists formulate and execute the correct treatment plan.

Innate immune cells can develop a long-lasting hyperresponsive phenotype by metabolic and epigenetic reprogramming after brief exposure to inflammatory stimuli. Several experimental studies convincingly demonstrated that this immunologic phenomenon, which is called trained immunity, can accelerate the development of atherosclerosis. In this brief review, we summarize current evidence that diets and specific dietary components can modulate trained immunity. In mice, intermittent high-fat diets can reprogram bone marrow myeloid progenitor cells, resulting in hyperinflammatory monocytes and neutrophils that aggravate atherosclerosis. Diet-induced obesity also leads to persistent proinflammatory epigenetic reprogramming of myeloid cells and adipocytes. Hyperglycemia and high-salt diets can also induce trained immunity in murine models. Recent intervention studies in Tanzania revealed that urban Western-style diets trigger systemic inflammation and immune activation, whereas a traditional plant-based heritage diet limits inflammation. Ex vivo studies suggest that this is caused, at least in part, by modulation of trained immunity. Various individual dietary components, such as the flavone apigenin and the polyphenol resveratrol, are able to prevent trained immunity in vitro. It is exciting to speculate how further molecular elucidation on the modulation of trained immunity by diets or isolated dietary components could help to prevent cardiovascular diseases.

Abstract Background Elevated levels of lipoprotein(a) [Lp(a)] is an independent and causal genetic risk factor for the development of atherosclerotic cardiovascular disease (ASCVD). Vascular regenerative (VR) cell exhaustion, or the depletion of circulating progenitor cells that mediate blood vessel repair, represents a novel indicator of compromised vessel repair in people living with type 2 diabetes or obesity, and among South Asian adults with elevated CVD risk. We hypothesize that Lp(a) levels may correlate positively with VR cell depletion. Purpose The cross-sectional, observational, multi-site Lp(a)-VRCE study compared the frequencies of circulating VR cell subsets from a total of 40 individuals with Lp(a) ≥100 nmol/L [High Lp(a); n=20] and Lp(a) &amp;lt;100 nmol/L [Low Lp(a); n=20]. Methods Peripheral blood mononuclear cells were subject to multi-parameter flow cytometry analyses based on the activity of high aldehyde dehydrogenase (ALDH), an antioxidative enzyme that is conserved in progenitor cells, in combination with side scatter and lineage-specific cell surface markers. Results Key baseline characteristics were comparable between the study groups and are summarized in the Table. Mean (SD) Lp(a) levels for the High and Low Lp(a) subgroups were 249.9±90.8 and 28.4±18.2 nmol/L (p&amp;lt;0.001) respectively. Approximately one-third of the participants was female; mean age of the cohort was 59 years; mean total cholesterol and eGFR were lower, and creatinine higher in the High Lp(a) group. While most in the High Lp(a) group were on a statin (90%), only 60% of the low Lp(a) participants were taking a statin. Individuals in the High Lp(a) group had lower frequencies of ALDHhiSSClowCD133+ (43±6 vs 51±8%, p&amp;lt;0.001) and ALDHhiSSClowCD34+CD133+ (44±7 vs 53±11%, p&amp;lt;0.01) early myeloid progenitor cells with previously established vessel regenerative functions. Those in the High Lp(a) group also exhibited increased M1-like pro-inflammatory polarization among circulating monocytes (ALDHhiSSCmidCD86+CD163-, 6.5±2.8 vs 4.0±2.6%, p&amp;lt;0.01). Conclusion Lp(a)-VRCE provides the first translational evidence that Lp(a) levels ≥100 nmol/L are associated with reduced VR myeloid progenitor cell content that is responsible for vessel repair, and increased M1-polarized monocyte content that contributes to plaque inflammation. Recovery of vessel repair via Lp(a)-lowering strategies may represent a novel approach to decrease vascular risk.Table Figure

Expression of natural killer cell ligands on Acute Myeloid Leukemia cells harboring various genetic and cytogenetic abnormalities

Menin inhibition as a new therapeutic option for the myeloproliferative neoplasms

Loss of serine threonine protein kinase 25 (STK25) in the bone marrow niche attenuates g/CSF- and TLR7-induced emergency myelopoiesis and mobilization into the periphery

Integrative clinical and molecular analysis of outcome in elderly African ancestry Acute Myeloid Leukemia