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The competitive advantage of mutant hematopoietic stem and progenitor cells (HSPCs) underlies clonal hematopoiesis (CH). Drivers of CH include aging and inflammation; however,how CH-mutant cells gain a selective advantage in these contexts is an unresolved question. Using a murine model of CH ( Dnmt3a R878H/+ ),we discover that mutant HSPCs sustain elevated mitochondrial respiration which is associated with their resistance to aging-related changes in the bone marrow microenvironment. Mutant HSPCs have DNA hypomethylation and increased expression of oxidative phosphorylation gene signatures,increased functional oxidative phosphorylation capacity,high mitochondrial membrane potential (Δψm),and greater dependence on mitochondrial respiration compared to wild-type HSPCs. Exploiting the elevated Δψm of mutant HSPCs,long-chain alkyl-TPP molecules (MitoQ,d-TPP) selectively accumulate in the mitochondria and cause reduced mitochondrial respiration,mitochondrial-driven apoptosis and ablate the competitive advantage of HSPCs ex vivo and in vivo in aged recipient mice. Further,MitoQ targets elevated mitochondrial respiration and the selective advantage of human DNMT3A -knockdown HSPCs,supporting species conservation. These data suggest that mitochondrial activity is a targetable mechanism by which CH-mutant HSPCs gain a selective advantage over wild-type HSPCs. Subject terms: Ageing,Haematopoietic stem cells,Mitochondria View Publication

The complete array of genes required for terminal erythroid differentiation remains unknown. To address this knowledge gap,we perform a genome-scale CRISPR knock-out screen in the human erythroid progenitor cell line HUDEP-2 and validate candidate regulators of erythroid differentiation in a custom secondary screen. Comparison of sgRNA abundance in the CRISPR library,proerythroblasts,and orthochromatic erythroblasts,resulted in the identification of genes that are essential for proerythroblast survival and genes that are required for terminal erythroid differentiation. Among the top genes identified are known regulators of erythropoiesis,underscoring the validity of this screen. Notably,using a Log2 fold change of <−1 and false discovery rate of <0.01,the screen identified 277 genes that are required for terminal erythroid differentiation,including multiple genes not previously nominated through GWAS. NHLRC2,which was previously implicated in hemolytic anemia,was a highly ranked gene. We suggest that anemia due to NHLRC2 mutation results at least in part from a defect in erythroid differentiation. Another highly ranked gene in the screen is VAC14,which we validated for its requirement in erythropoiesis in vitro and in vivo. Thus,data from this CRISPR screen may help classify the underlying mechanisms that contribute to erythroid disorders. Subject terms: Erythropoiesis,CRISPR-Cas9 genome editing,Haematopoietic stem cells View Publication

Biliverdin IXβ reductase (BLVRB) is an NADPH-dependent enzyme previously implicated in a redox-regulated mechanism of thrombopoiesis distinct from the thrombopoietin (TPO)/c-MPL axis. Here,we apply computational modeling to inform molecule design,followed by de novo syntheses and screening of unique small molecules retaining the capacity for selective BLVRB inhibition as a novel platelet-enhancing strategy. Two distinct classes of molecules are identified,and NMR spectroscopy and co-crystallization studies confirm binding modes within the BLVRB active site and ring stacking between the nicotinamide moiety of the NADP + cofactor. A diazabicyclo derivative displaying minimal off-target promiscuity and excellent bioavailability characteristics promotes megakaryocyte speciation in biphenotypic (erythro/megakaryocyte) cellular models and synergizes with TPO-dependent megakaryocyte formation in hematopoietic stem cells. Upon oral delivery into mice,this inhibitor expands platelet recovery in stress thrombopoietic models with no adverse effects. In this work,we identify and validate a cellular redox inhibitor retaining the potential to selectively promote megakaryocytopoiesis and enhance stress-associated platelet formation in vivo distinct from TPO receptor agonists. Subject terms: Target validation,Medicinal chemistry,X-ray crystallography,Computational biophysics View Publication

Osteoporosis diagnoses are increasing in the ageing population,and although some treatments exist,these have several disadvantages,highlighting the need to identify new drug targets. G protein-coupled receptors (GPCRs) are transmembrane proteins whose surface expression and extracellular activation make them desirable drug targets. Our previous studies have identified 144 GPCR genes to be expressed in primary human osteoclasts,which could provide novel drug targets. The development of high-throughput assays to assess osteoclast activity would improve the efficiency at which we could assess the effect of GPCR activation on human bone cells and could be utilised for future compound screening. Here,we assessed the utility of a high-content imaging (HCI) assay that measured cytoplasmic-to-nuclear translocation of the nuclear factor of activated T cells-1 (NFATc1),a transcription factor that is essential for osteoclast differentiation,and resorptive activity. We first demonstrated that the HCI assay detected changes in NFATc1 nuclear translocation in human primary osteoclasts using GIPR as a positive control,and then developed an automated analysis platform to assess NFATc1 in nuclei in an efficient and unbiased manner. We assessed six GPCRs simultaneously and identified four receptors (FFAR2,FFAR4,FPR1 and GPR35) that reduced osteoclast activity. Bone resorption assays and measurements of TRAP activity verified that activation of these GPCRs reduced osteoclast activity,and that receptor-specific antagonists prevented these effects. These studies demonstrate that HCI of NFATc1 can accurately assess osteoclast activity in human cells,reducing observer bias and increasing efficiency of target detection for future osteoclast-targeted osteoporosis therapies. View Publication

Acute myeloid leukemia (AML) is the most common type of acute leukemia in adults. We previously discovered that heme oxygenase 1 (HO1) is crucial for chemoresistance in AML,but the detailed molecular mechanism of that remains unclear. RNA sequencing was conducted to assess transcriptomic changes in three pairs of AML cells after regulating the expression of HO1. The molecular mechanism by which HO1 induces gilteritinib resistance in FLT3-ITD (FMS-like tyrosine kinase 3 (FLT3) internal tandem duplication (ITD)) AML was evaluated by quantitative real-time PCR (qRT-PCR),CCK-8,flow cytometry,and western blotting. FLT3-ITD AML mouse models were established to investigate the effects of HO1 expression on gilteritinib resistance in vivo. In these three pairs of AML cells,we discovered that HO1-mediated drug resistance is connected to the interleukin-4-mediated signaling pathway (specifically STAT6) only in MV4-11 cells with the FLT3-ITD mutation. Further findings revealed that HO1 overexpression confers gilteritinib resistance in FLT3-ITD AML cell lines and primary individual specimens. While suppression of HO1 sensitized FLT3-ITD AML cell lines and primary individual specimens to gilteritinib. Mechanistically,western blotting and flow cytometry confirmed that HO1-mediated gilteritinib resistance is related to STAT6 phosphorylation in FLT3-ITD AML cell lines and primary individual specimens. Moreover,tumor-bearing mice were employed to determine that HO1 overexpression conferred gilteritinib resistance in vivo. Collectively,these studies illustrate that HO1 may act as a successful treatment target for gilteritinib-resistant FLT3-ITD AML patients. The online version contains supplementary material available at 10.1186/s12935-025-03757-3. View Publication

Trogocytosis is the process by which a recipient cell siphons small membrane fragments and proteins from a donor cell and can be utilized by cancer cells to avoid immune detection. We observed lymphocyte specific protein expressed by triple negative breast cancer (TNBC) cells via immunofluorescence imaging of patient samples. Image analysis of Cluster of Differentiation 45RA (CD45RA) expression,a naïve T cell specific protein,revealed that all stages of TNBCs express CD45RA. Flow cytometry revealed TNBC cells trogocytose CD45 protein from T cells. We also showed that the acquisition of these lymphoid markers is contact dependent. Confocal and super-resolution imaging further revealed CD45+ spherical structures containing T cell genomic DNA inside TNBC cells after co-culture. Trogocytosis between T cells and TNBC cells altered tumor cell expression of PTPRC,the gene that encodes for CD45. Our results revealed that CD45 is obtained by TNBC cells from T cells via trogocytosis and that TNBC cells express CD45 intracellularly and on the membrane. View Publication

Designer receptors exclusively activated by designer drugs (DREADDs) are established tools for modulating neuronal activity. Calcium-mobilizing DREADD hM3Dq has been widely used to enhance neuronal activity. hM3Dq activates the Gq protein signaling cascade and mimics the action of native Gq protein-coupled receptors such as muscarinic m1 and m3 receptors leading to calcium release from intracellular storages. Depolarization evoked by increased intracellular calcium levels is an important factor for neuronal maturation. Here,we used repetitive activation of biolistically overexpressed hM3Dq to increase the activity of individual neurons differentiating in organotypic slice cultures of rat visual cortex. HM3Dq was activated by 3 μM clozapine-N-oxide (CNO) dissolved in H 2 O. Transfectants expressing hM3Dq mock-stimulated with H 2 O served as batch-internal controls. Pyramidal cells and multipolar interneurons were analyzed after treatment from DIV 5–10,DIV 10–20,and DIV 15–20 to investigate if Gq signaling is involved in dendritic maturation. Results show that hM3Dq activation accelerated the maturation of apical dendrites of L2/3 pyramidal cells in the early,but no longer in the later time windows. In contrast,dendritic dimensions of L5/6 pyramidal cells and interneurons were not altered at DIV 10. These findings suggest a growth-promoting role of activated Gq signaling selectively for early postnatal L2/3 pyramidal cells. Unexpectedly,hM3Dq activation from DIV 10–20 reduced the dendritic complexity of L5/6 pyramidal cells and multipolar interneurons. Together,results suggest a role of Gq signaling for neuronal differentiation and support evidence that it may also limit dendritic growth. View Publication

To produce pluripotent stem cells from peripheral blood mononuclear cells (PBMCs) of a patient with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and culture and differentiate them into vascular organoids,producing a disease model for cerebral small vessel disease (CSVD). (1) PMBCs from patients clinically diagnosed with CADASIL ( NOTCH3 p.R141C) were induced to differentiate into pluripotent stem cells (iPSCs); the quality and differentiation ability of the iPSCs were determined. (2) CADASIL-derived iPSCs and control iPSCs were cultured and differentiated into vascular organoids. The differences in the morphological structure of the two differentiated groups of vascular organoids were observed,and both were identified. (1) No mycoplasma infections were detected in the iPSCs prepared from the PBMCs of patients with CADASIL. The short tandem repeat (STR) identification verified that the iPSCs originated from the patient,and the karyotype was normal. Flow cytometry and immunofluorescence detection revealed that the iPSCs expressed SSEA4,OCT4,and NANOG stem proteins. Tri-germ differentiation testing confirmed that the iPSCs expressed the endoderm markers SOX17 and FOXA2,the mesoderm markers Brachyury and α-SMA,and the ectoderm markers Pax6 and β-III Tubulin. (2) CADASIL-derived iPSCs and control iPSCs were induced to differentiate and produce endothelial networks and vascular networks,ultimately forming vascular organoids. Compared with control vascular organoids,CADASIL vascular organoids exhibited lower growth density,earlier blood vessel sprouting,longer and thinner vascular filaments,and smaller final vascular organoids. The vascular organoids from the two sources expressed the endothelial cell marker CD31,the vascular smooth muscle marker α-SMA,and the pericyte marker PDGFR-β. Reprogramming technology can be used to induce PBMCs to become iPSCs,and a CSVD disease model can be successfully constructed by culturing and differentiating the iPSCs into CADASIL vascular organoids. The NOTCH3 p.R141C mutation suppresses the vascular differentiation process in CADASIL. View Publication

The search for an effective cell replacement therapy for diabetes has driven the development of “perfect” pancreatic islets from human pluripotent stem cells (hPSCs). These hPSC-derived pancreatic islet-like β cells can overcome the limitations for disease modelling,drug development and transplantation therapies in diabetes. Nevertheless,challenges remain in generating fully functional and mature β cells from hPSCs. This review underscores the significant efforts made by researchers to optimize various differentiation protocols aimed at enhancing the efficiency and quality of hPSC-derived pancreatic islets and proposes methods for their improvement. By emulating the natural developmental processes of pancreatic embryogenesis,specific growth factors,signaling molecules and culture conditions are employed to guide hPSCs towards the formation of mature β cells capable of secreting insulin in response to glucose. However,the efficiency of these protocols varies greatly among different human embryonic stem cell (hESC) and induced pluripotent stem cell (hiPSC) lines. This variability poses a particular challenge for generating patient-specific β cells. Despite recent advancements,the ultimate goal remains to develop a highly efficient directed differentiation protocol that is applicable across all genetic backgrounds of hPSCs. Although progress has been made,further research is required to optimize the protocols and characterization methods that could ensure the safety and efficacy of hPSC-derived pancreatic islets before they can be utilized in clinical settings. View Publication

Ageing is the most prominent risk factor for Alzheimer’s disease (AD). However,the cellular mechanisms linking neuronal proteostasis decline to the characteristic aberrant protein deposits in the brains of patients with AD remain elusive. Here we develop transdifferentiated neurons (tNeurons) from human dermal fibroblasts as a neuronal model that retains ageing hallmarks and exhibits AD-linked vulnerabilities. Remarkably,AD tNeurons accumulate proteotoxic deposits,including phospho-tau and amyloid β,resembling those in APP mouse brains and the brains of patients with AD. Quantitative tNeuron proteomics identify ageing- and AD-linked deficits in proteostasis and organelle homeostasis,most notably in endosome–lysosomal components. Lysosomal deficits in aged tNeurons,including constitutive lysosomal damage and ESCRT-mediated lysosomal repair defects,are exacerbated in AD tNeurons and linked to inflammatory cytokine secretion and cell death. Providing support for the centrality of lysosomal deficits in AD,compounds ameliorating lysosomal function reduce amyloid β deposits and cytokine secretion. Thus,the tNeuron model system reveals impaired lysosomal homeostasis as an early event of ageing and AD. Subject terms: Organelles,Protein folding View Publication

Motor axon regeneration following peripheral nerve injury is critical for motor recovery but therapeutic interventions enhancing this are not available. We conduct a phenotypic screen on human motor neurons and identified blebbistatin,a non-muscle myosin II inhibitor,as the most effective neurite outgrowth promotor. Despite its efficacy in vitro,its poor bioavailability limits in vivo application. We,therefore,utilize a blebbistatin analog,NMIIi2,to explore its therapeutic potential for promoting axon regeneration. Local NMIIi2 application directly to injured axons enhances regeneration in human motor neurons. Furthermore,following a sciatic nerve crush injury in male mice,local NMIIi2 administration to the axonal injury site facilitates motor neuron regeneration,muscle reinnervation,and functional recovery. NMIIi2 also promotes axon regeneration in sensory,cortical,and retinal ganglion neurons. These findings highlight the therapeutic potential of topical NMII inhibition for treating axon damage. Subject terms: Regeneration and repair in the nervous system,Movement disorders View Publication

Beckwith-Wiedemann Syndrome (BWS) is an epigenetic overgrowth syndrome caused by methylation changes in the human 11p15 chromosomal locus. Patients with BWS may exhibit hepatomegaly,as well as an increased risk of hepatoblastoma. To understand the impact of these 11p15 changes in the liver,we performed a multiomic study [single nucleus RNA-sequencing (snRNA-seq) + single nucleus assay for transposable-accessible chromatin-sequencing (snATAC-seq)] of both BWS-liver and nonBWS-liver tumor-adjacent tissue. Our approach uncovers hepatocyte-specific enrichment of processes related to peroxisome proliferator—activated receptor alpha (PPARA). To confirm our findings,we differentiated a BWS induced pluripotent stem cell model into hepatocytes. Our data demonstrate the dysregulation of lipid metabolism in BWS-liver,which coincides with observed upregulation of PPARA during hepatocyte differentiation. BWS hepatocytes also exhibit decreased neutral lipids and increased fatty acid β-oxidation. We also observe increased reactive oxygen species byproducts in BWS hepatocytes,coinciding with increased oxidative DNA damage. This study proposes a putative mechanism for overgrowth and cancer predisposition in BWS liver due to perturbed metabolism. Subject terms: Paediatric research,Imprinting View Publication