技术资料

Epicardium,the most outer mesothelium,exerts crucial functions in fetal heart development and adult heart regeneration. Here we use a three-step manipulation of WNT signalling entwined with BMP and RA signalling for generating a self-organized epicardial organoid that highly express with epicardium makers WT1 and TCF21 from human embryonic stem cells. After 8-days treatment of TGF-beta following by bFGF,cells enter into epithelium-mesenchymal transition and give rise to smooth muscle cells. Epicardium could also integrate and invade into mouse heart with SNAI1 expression,and give birth to numerous cardiomyocyte-like cells. Single-cell RNA seq unveils the heterogeneity and multipotency exhibited by epicardium-derived-cells and fetal-like epicardium. Meanwhile,extracellular matrix and growth factors secreted by epicardial organoid mimics the ecology of subepicardial space between the epicardium and cardiomyocytes. As such,this epicardial organoid offers a unique ground for investigating and exploring the potential of epicardium in heart development and regeneration.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13578-024-01339-w. View Publication

BackgroundEmbryonic development requires the accurate spatiotemporal execution of cell lineage-specific gene expression programs,which are controlled by transcriptional enhancers. Developmental enhancers adopt a primed chromatin state prior to their activation. How this primed enhancer state is established and maintained and how it affects the regulation of developmental gene networks remains poorly understood.ResultsHere,we use comparative multi-omic analyses of human and mouse early embryonic development to identify subsets of postgastrulation lineage-specific enhancers which are epigenetically primed ahead of their activation,marked by the histone modification H3K4me1 within the epiblast. We show that epigenetic priming occurs at lineage-specific enhancers for all three germ layers and that epigenetic priming of enhancers confers lineage-specific regulation of key developmental gene networks. Surprisingly in some cases,lineage-specific enhancers are epigenetically marked already in the zygote,weeks before their activation during lineage specification. Moreover,we outline a generalizable strategy to use naturally occurring human genetic variation to delineate important sequence determinants of primed enhancer function.ConclusionsOur findings identify an evolutionarily conserved program of enhancer priming and begin to dissect the temporal dynamics and mechanisms of its establishment and maintenance during early mammalian development.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13059-025-03658-8. View Publication

SummaryNeonatal mouse hearts have transient renewal capacity,which is lost in juvenile and adult stages. In neonatal mouse hearts,myocardial infarction (MI) causes an initial loss of cardiomyocytes. However,it is unclear which type of regulated cell death (RCD) occurs in stressed cardiomyocytes. In the current studies,we induced MI in neonatal and juvenile mouse hearts and showed that ischemic cardiomyocytes primarily undergo ferroptosis,a non-apoptotic and iron-dependent form of RCD. We demonstrated that cardiac fibroblasts (CFs) protect cardiomyocytes from ferroptosis through paracrine effects and direct cell-cell interaction. CFs show strong resistance to ferroptosis due to high ferritin expression. The fibrogenic activity of CFs,typically considered detrimental to heart function,is negatively regulated by paired-like homeodomain 2 (Pitx2) signaling from cardiomyocytes. In addition,Pitx2 prevents ferroptosis in cardiomyocytes by regulating ferroptotic genes. Understanding the regulatory mechanisms of cardiomyocyte survival and death can identify potentially translatable therapeutic strategies for MI. Graphical abstract Highlights•Neonatal and juvenile mouse cardiomyocytes mainly undergo ferroptosis after MI•Cardiac fibroblasts protect cardiomyocytes through paracrine effect•Cardiac fibroblasts interact with cardiomyocytes to share iron burden•Pitx2 pathway protects cardiomyocytes from ferroptosis and controls fibrosis Cardiovascular medicine; Physiology; Cell biology View Publication

ABSTRACTProneural genes are conserved drivers of neurogenesis across the animal kingdom. How their functions have adapted to guide human-specific neurodevelopmental features is poorly understood. Here,we mined transcriptomic data from human fetal cortices and generated from human embryonic stem cell-derived cortical organoids (COs) to show that NEUROG1 and NEUROG2 are most highly expressed in basal neural progenitor cells,with pseudotime trajectory analyses indicating that NEUROG1-derived lineages predominate early and NEUROG2 lineages later. Using ChIP-qPCR,gene silencing and overexpression studies in COs,we show that NEUROG2 is necessary and sufficient to directly transactivate known target genes (NEUROD1,EOMES,RND2). To identify new targets,we engineered NEUROG2-mCherry knock-in human embryonic stem cells for CO generation. The mCherry-high CO cell transcriptome is enriched in extracellular matrix-associated genes,and two genes associated with human-accelerated regions: PPP1R17 and FZD8. We show that NEUROG2 binds COL1A1,COL3A1 and PPP1R17 regulatory elements,and induces their ectopic expression in COs,although NEUROG2 is not required for this expression. Neurog2 similarly induces Col3a1 and Ppp1r17 in murine P19 cells. These data are consistent with a conservation of NEUROG2 function across mammalian species. Summary: Analysis of human cortical organoids reveals that NEUROG1 lineages prevail early and NEUROG2 lineages later,and that NEUROG2 targets include COL genes and PPP1R17,a human-accelerated region-associated gene. View Publication

Lateral Meningocele Syndrome (LMS),a disorder associated with NOTCH3 pathogenic variants,presents with neurological,craniofacial and skeletal abnormalities. Mouse models of the disease exhibit osteopenia that is ameliorated by the administration of Notch3 antisense oligonucleotides (ASO) targeting either Notch3 or the Notch3 mutation. To determine the consequences of LMS pathogenic variants in human cells and whether they can be targeted by ASOs,induced pluripotent NCRM1 and NCRM5 stem (iPS) cells harboring a NOTCH36692-93insC insertion were created. Parental iPSCs,NOTCH36692-93insC and isogenic controls,free of chromosomal aberrations as determined by human CytoSNP850 array,were cultured under conditions of neural crest,mesenchymal and osteogenic cell differentiation. The expected cell phenotype was confirmed by surface markers and a decline in OCT3/4 and NANOG mRNA. NOTCH36692-93insC cells displayed enhanced expression of Notch target genes HES1,HEY1,2 and L demonstrating a NOTCH3 gain-of-function. There was enhanced osteogenesis in NOTCH36692-93insC cells as evidenced by increased mineralized nodule formation and ALPL,BGLAP and BSP expression. ASOs targeting NOTCH3 decreased both NOTCH3 wild type and NOTCH36692-93insC mutant mRNA by 40% in mesenchymal and 90% in osteogenic cells. ASOs targeting the NOTCH3 insertion decreased NOTCH36692-93insC by 70–80% in mesenchymal cells and by 45–55% in osteogenic cells and NOTCH3 mRNA by 15–30% and 20–40%,respectively. In conclusion,a NOTCH3 pathogenic variant causes a modest increase in osteoblastogenesis in human iPS cells in vitro and NOTCH3 and NOTCH3 mutant specific ASOs downregulate NOTCH3 transcripts associated with LMS. View Publication

Mutations in FUS and TARDBP cause amyotrophic lateral sclerosis (ALS),but the precise mechanisms of selective motor neuron degeneration remain unresolved. To address if pathomechanisms are shared across mutations and related to either gain- or loss-of-function,we performed single-cell RNA sequencing across isogenic induced pluripotent stem cell-derived neuron types,harbouring FUS P525L,FUS R495X,TARDBP M337V mutations or FUS knockout. Transcriptional changes were far more pronounced in motor neurons than interneurons. About 20% of uniquely dysregulated motor neuron transcripts were shared across FUS mutations,half from gain-of-function. Most indicated mitochondrial impairments,with attenuated pathways shared with mutant TARDBP M337V as well as C9orf72-ALS patient motor neurons. Mitochondrial motility was impaired in ALS motor axons,even with nuclear localized FUS mutants,demonstrating shared toxic gain-of-function mechanisms across FUS- and TARDBP-ALS,uncoupled from protein mislocalization. These early mitochondrial dysfunctions unique to motor neurons may affect survival and represent therapeutic targets in ALS. In this study,the authors performed single-cell RNA-sequencing across various isogenic mutant FUS and TDP43 neurons. Mitochondrial dysfunction emerged as pathway unique to motor neurons demonstrating shared toxic gain of-function mechanisms,uncoupled from protein mislocalization. View Publication

BCR/ABL-transformed chronic myeloid leukemia (CML) cells accumulate numerous DNA double-strand breaks (DSB) induced by reactive oxygen species (ROS) and genotoxic agents. To repair these lesions BCR/ABL stimulate unfaithful DSB repair pathways,homologous recombination repair (HRR),nonhomologous end-joining (NHEJ),and single-strand annealing (SSA). Here,we show that BCR/ABL enhances the expression and increase nuclear localization of WRN (mutated in Werner syndrome),which is required for processing DSB ends during the repair. Other fusion tyrosine kinases (FTK),such as TEL/ABL,TEL/JAK2,TEL/PDGFβR,and NPM/ALK also elevate WRN. BCR/ABL induces WRN mRNA and protein expression in part by c-MYC-mediated activation of transcription and Bcl-xL-dependent inhibition of caspase-dependent cleavage,respectively. WRN is in complex with BCR/ABL resulting in WRN tyrosine phosphorylation and stimulation of its helicase and exonuclease activities. Activated WRN protects BCR/ABL-positive cells from the lethal effect of oxidative and genotoxic stresses,which causes DSBs. In addition,WRN promotes unfaithful recombination-dependent repair mechanisms HRR and SSA,and enhances the loss of DNA bases during NHEJ in leukemia cells. In summary,we postulate that BCR/ABL-mediated stimulation of WRN modulates the efficiency and fidelity of major DSB repair mechanisms to protect leukemia cells from apoptosis and to facilitate genomic instability. View Publication

Recessive dystrophic epidermolysis bullosa (RDEB) is an inherited blistering skin disorder caused by mutations in the COL7A1 gene-encoding type VII collagen (Col7),the major component of anchoring fibrils at the dermal-epidermal junction. Individuals with RDEB develop painful blisters and mucosal erosions,and currently,there are no effective forms of therapy. Nevertheless,some advances in patient therapy are being made,and cell-based therapies with mesenchymal and hematopoietic cells have shown promise in early clinical trials. To establish a foundation for personalized,gene-corrected,patient-specific cell transfer,we generated induced pluripotent stem (iPS) cells from three subjects with RDEB (RDEB iPS cells). We found that Col7 was not required for stem cell renewal and that RDEB iPS cells could be differentiated into both hematopoietic and nonhematopoietic lineages. The specific epigenetic profile associated with de-differentiation of RDEB fibroblasts and keratinocytes into RDEB iPS cells was similar to that observed in wild-type (WT) iPS cells. Importantly,human WT and RDEB iPS cells differentiated in vivo into structures resembling the skin. Gene-corrected RDEB iPS cells expressed Col7. These data identify the potential of RDEB iPS cells to generate autologous hematopoietic grafts and skin cells with the inherent capacity to treat skin and mucosal erosions that typify this genodermatosis. View Publication

In the hematopoietic hierarchy,only stem cells are thought to be capable of long-term self-renewal. Erythroid progenitors derived from fetal or adult mammalian hematopoietic tissues are capable of short-term,or restricted (10(2)- to 10(5)-fold),ex vivo expansion in the presence of erythropoietin,stem cell factor,and dexamethasone. Here,we report that primary erythroid precursors derived from early mouse embryos are capable of extensive (10(6)- to 10(60)-fold) ex vivo proliferation. These cells morphologically,immunophenotypically,and functionally resemble proerythroblasts,maintaining both cytokine dependence and the potential,despite prolonged culture,to generate enucleated erythrocytes after 3-4 maturational cell divisions. This capacity for extensive erythroblast self-renewal is temporally associated with the emergence of definitive erythropoiesis in the yolk sac and its transition to the fetal liver. In contrast,hematopoietic stem cell-derived definitive erythropoiesis in the adult is associated almost exclusively with restricted ex vivo self-renewal. Primary primitive erythroid precursors,which lack significant expression of Kit and glucocorticoid receptors,lack ex vivo self-renewal capacity. Extensively self-renewing erythroblasts,despite their near complete maturity within the hematopoietic hierarchy,may ultimately serve as a renewable source of red cells for transfusion therapy. View Publication

Integrins are cell adhesion receptors that mediate cell-to-cell,or cell-to-extracellular matrix adhesion. They represent an attractive target for treatment of multiple diseases. Two classes of small molecule integrin inhibitors have been developed. Competitive antagonists bind directly to the integrin ligand binding pocket and thus disrupt the ligand-receptor interaction. Allosteric antagonists have been developed primarily for α(L)β(2)- integrin (LFA-1,lymphocyte function-associated antigen-1). Here we present the results of screening the Prestwick Chemical Library using a recently developed assay for the detection of α(4)β(1)-integrin allosteric antagonists. Secondary assays confirmed that the compounds identified: 1) do not behave like competitive (direct) antagonists; 2) decrease ligand binding affinity for VLA-4 ∼2 orders of magnitude; 3) exhibit antagonistic properties at low temperature. In a cell based adhesion assay in vitro,the compounds rapidly disrupted cellular aggregates. In accord with reports that VLA-4 antagonists in vivo induce mobilization of hematopoietic progenitors into the peripheral blood,we found that administration of one of the compounds significantly increased the number of colony-forming units in mice. This effect was comparable to AMD3100,a well known progenitor mobilizing agent. Because all the identified compounds are structurally related,previously used,or currently marketed drugs,this result opens a range of therapeutic possibilities for VLA-4-related pathologies. View Publication

The molecular basis of CNS myelin regeneration (remyelination) is poorly understood. We generated a comprehensive transcriptional profile of the separate stages of spontaneous remyelination that follow focal demyelination in the rat CNS and found that transcripts that encode the retinoid acid receptor RXR-γ were differentially expressed during remyelination. Cells of the oligodendrocyte lineage expressed RXR-γ in rat tissues that were undergoing remyelination and in active and remyelinated multiple sclerosis lesions. Knockdown of RXR-γ by RNA interference or RXR-specific antagonists severely inhibited oligodendrocyte differentiation in culture. In mice that lacked RXR-γ,adult oligodendrocyte precursor cells efficiently repopulated lesions after demyelination,but showed delayed differentiation into mature oligodendrocytes. Administration of the RXR agonist 9-cis-retinoic acid to demyelinated cerebellar slice cultures and to aged rats after demyelination caused an increase in remyelinated axons. Our results indicate that RXR-γ is a positive regulator of endogenous oligodendrocyte precursor cell differentiation and remyelination and might be a pharmacological target for regenerative therapy in the CNS. View Publication

Autologous bone grafting represents the gold standard modality to treat atrophic non-unions by virtue of its osteoinductive and osteoconductive properties. The common harvest site is the iliac crest,but there are major concerns due to limited volume and considerable donor site morbidity. Alternative autologous bone graft can be harvested from the femoral bone cavity using a newly developed 'Reamer Irrigator Aspirator' (RIA). Osseous aspirated particles can be recovered with a filter and used as auto-graft. The purpose of this study was to compare the concentration and differentiation potential of mesenchymal stem cells (MSC) and endothelial progenitor cells (EPC) harvested with the RIA technique or from the iliac crest,respectively. RIA aspirate was collected from 26 patients undergoing intramedullary nailing of femur fractures. Iliac crest aspirate was collected from 38 patients undergoing bone graft transplantation. Concentration of MSC and EPC were assessed by means of the MSC colony assay,EPC culture assay and flowcytometry (CD34,CD133,VEGF-R2),respectively. Osteogenic differentiation of MSC's was measured by von Kossa staining. Patients in both groups did not significantly differ regarding their age,gender or pre-existing health conditions. In comparison to aspirates obtained from iliac crest the RIA aspirates from the femur contained a significantly higher percentage of CD34+ progenitor cells,a significantly higher concentration of MSC and a significantly higher concentration of early EPC. The percentage of late EPC did not differ between both sites. Moreover,the capability of MSC for calcium deposition was significantly enhanced in MSC obtained with RIA. Our results show that RIA aspirate is a rich source for different types of autologous progenitor cells,which can be used to accelerate healing of bone and other musculoskeletal tissues. View Publication