技术资料

BackgroundHuman pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) show tremendous promise for cardiac regeneration following myocardial infarction (MI),but their transplantation gives rise to transient ventricular tachycardia (VT) in large-animal MI models,representing a major hurdle to translation. Our group previously reported that these arrhythmias arise from a focal mechanism whereby graft tissue functions as an ectopic pacemaker; therefore,we hypothesized that hPSC-CMs engineered with a dominant negative form of the pacemaker ion channel HCN4 (dnHCN4) would exhibit reduced automaticity and arrhythmogenic risk following transplantation.MethodsWe used CRISPR/Cas9-mediated gene-editing to create transgenic dnHCN4 hPSC-CMs,and their electrophysiological behavior was evaluated in vitro by patch-clamp recordings and optical mapping. Next,we transplanted WT and homozygous dnHCN4 hPSC-CMs in a pig MI model and compared post-transplantation outcomes including the incidence of spontaneous arrhythmias and graft structure by immunohistochemistry.ResultsIn vitro dnHCN4 hPSC-CMs exhibited significantly reduced automaticity and pacemaker funny current (If) density relative to wildtype (WT) cardiomyocytes. Following transplantation with either dnHCN4 or WT hPSC-CMs,all recipient hearts showed transmural infarct scar that was partially remuscularized by scattered islands of human myocardium. However,in contrast to our hypothesis,both dnHCN4 and WT hPSC-CM recipients exhibited frequent episodes of ventricular tachycardia (VT).ConclusionsWhile genetic silencing of the pacemaker ion channel HCN4 suppresses the automaticity of hPSC-CMs in vitro,this intervention is insufficient to reduce VT risk post-transplantation in the pig MI model,implying more complex mechanism(s) are operational in vivo. View Publication

Targeted genome editing of human pluripotent stem cells (hPSCs) is critical for basic and translational research and can be achieved with site-specific endonucleases. Cpf1 (CRISPR from Prevotella and Francisella) is a programmable DNA endonuclease with AT-rich PAM sequences. In this protocol,we describe procedures for using a single vector system to deliver Cpf1 and CRISPR RNA (crRNA) for genome editing in hPSCs. This protocol enables indel formation and homologous recombination-mediated precise editing at multiple loci. With the delivery of Cpf1 and a single U6 promoter-driven guide RNA array composed of an AAVS1-targeting and a MAFB-targeting crRNA array,efficient multiplex genome editing at the AAVS1 (knockin) and MAFB (knockout) loci in hPSCs could be achieved in a single experiment. The edited hPSCs expressed pluripotency markers and could differentiate into neurons in vitro. This system also generated INS reporter hPSCs with a 6 kb cassette knockin at the INS locus. The INS reporter cells can differentiate into β-cells that express tdTomato and luciferase,permitting fluorescence-activated cell sorting of hPSC-β-cells. By targeted screening of potential off-target sequences that are most homologous to crRNA sequences,no off-target mutations were detected in any of the tested sequences. This work provides an efficient and flexible system for precise genome editing in mammalian cells including hPSCs with the benefits of less off-target effects. Key features • A single-vector system to deliver Cpf1 and crRNA enables the sorting of transfected cells • Efficient and simultaneous multi-modular genome editing exemplified by mutation of MAFB and knockin of AAVS1 loci in a single experiment • Edited PSCs showed minimal off-target effects and can be differentiated into multiple cell types. View Publication

Cardiac hypertrophy is a cellular process characterized by the increased size of cardiomyocytes in response to a high workload or stress. 17-beta estradiol (E2) has cardioprotective and anti-hypertrophic effects by maintaining mitochondrial network and function. MUL1 is a mitochondrial ubiquitin ligase directly involved in the control of mitochondrial fission and mitophagy. Studies from our group and others have previously shown that cardiomyocyte hypertrophy is associated with mitochondrial fission and dysfunction. These findings led us to study in vitro whether E2 regulates MUL1 to prevent cardiac hypertrophy,mitochondrial fission,and dysfunction induced by the catecholamine norepinephrine (NE). Our results showed that NE induces hypertrophy in cultured rat cardiomyocytes. Pre-treatment with E2 (10-100?nM) prevented the NE-dependent increases in cell perimeter and the hypertrophic stress markers ANP and BNP at both the protein and mRNA levels. NE induced the fragmentation of the mitochondrial network and reduced ATP levels,effects that were both prevented by E2. In silico analysis suggested a putative binding site for estrogen receptors on the MUL1 gene promoter. In accordance with this finding,E2 prevented increases in MUL1 mRNA and protein levels induced by NE. Our data also showed that a siRNA MUL1 knockdown counteracted NE-induced cardiomyocyte hypertrophy and mitochondrial dysfunction,mirroring the protective effect triggered by E2. In contrast,a MUL1 adenovirus did not prevent the E2 protection from cardiomyocyte hypertrophy. Further,in vivo analysis in a transgenic mouse model overexpressing MUL1 revealed that only young male mice overexpressed the protein. Consequently,they exhibited increased levels of the hypertrophic marker ANP,an elevated heart weight,and larger cardiomyocyte size. Therefore,our data demonstrate that 17-beta estradiol prevents cardiac myocyte hypertrophy by regulating MUL1. View Publication

BackgroundSpinal ventral root avulsion results in massive motoneuron degeneration with poor prognosis and high costs. In this study,we compared different isoforms of basic fibroblast growth factor 2 (FGF2),overexpressed in stably transfected Human embryonic stem cells (hESCs),following motor root avulsion and repair with a heterologous fibrin biopolymer (HFB).MethodsIn the present work,hESCs bioengineered to overexpress 18,23,and 31 kD isoforms of FGF2,were used in combination with reimplantation of the avulsed roots using HFB. Statistical analysis was conducted using GraphPad Prism software with one-way or two-way ANOVA,followed by Tukey’s or Dunnett’s multiple comparison tests. Significance was set at *p < 0.05,**p < 0.01,***p < 0.001,and ****p < 0.0001.ResultsFor the first set of experiments,rats underwent avulsion of the ventral roots with local administration of HFB and engraftment of hESCs expressing the above-mentioned FGF2 isoforms. Analysis of motoneuron survival,glial reaction,and synaptic coverage,two weeks after the lesion,indicated that therapy with hESCs overexpressing 31 kD FGF2 was the most effective. Consequently,the second set of experiments was performed with that isoform,so that ventral root avulsion was followed by direct spinal cord reimplantation. Motoneuron survival,glial reaction,synaptic coverage,and gene expression were analyzed 2 weeks post-lesion; while the functional recovery was evaluated by the walking track test and von Frey test for 12 weeks. We showed that engraftment of hESCs led to significant neuroprotection,coupled with immunomodulation,attenuation of astrogliosis,and preservation of inputs to the rescued motoneurons. Behaviorally,the 31 kD FGF2 - hESC therapy enhanced both motor and sensory recovery.ConclusionTransgenic hESCs were an effective delivery platform for neurotrophic factors,rescuing axotomized motoneurons and modulating glial response after proximal spinal cord root injury,while the 31 kD isoform of FGF2 showed superior regenerative properties over other isoforms in addition to the significant functional recovery.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13287-024-03676-6. View Publication

Stargardt disease is an inherited retinopathy affecting approximately 1:8000 individuals. It is characterised by biallelic variants in ABCA4 which encodes a vital protein for the recycling of retinaldehydes in the retina. Despite its prevalence and impact,there are currently no treatments available for this condition. Furthermore,35% of STGD1 cases remain genetically unsolved. To investigate the cellular and molecular characteristics associated with STGD1,we generated iPSCs from two monoallelic unresolved (PT1 & PT2),late-onset STGD1 cases with the heterozygous complex allele - c.[5461-10?T?>?C;5603?A?>?T]. Both patient iPSCs and those from a biallelic affected control (AC) carrying -c.4892?T?>?C and c.4539+2001G?>?A,were differentiated to retinal organoids,which developed all key retinal neurons and photoreceptors with outer segments positive for ABCA4 expression. We observed patient-specific disruption to lamination with OPN1MW/LW+ cone photoreceptor retention in the retinal organoid centre during differentiation. Photoreceptor retention was more severe in the AC case affecting both cones and rods,suggesting a genotype/phenotype correlation. scRNA-Seq suggests retention may be due to the induction of stress-related pathways in photoreceptors. Whole genome sequencing successfully identified the missing alleles in both cases; PT1 reported c.-5603A?>?T in homozygous state and PT2 uncovered a rare hypomorph - c.-4685T?>?C. Furthermore,retinal organoids were able to recapitulate the retina-specific splicing defect in PT1 as shown by long-read RNA-seq data. Collectively,these results highlight the suitability of retinal organoids in STGD1 modelling. Their ability to display genotype-phenotype correlations enhances their utility as a platform for therapeutic development. View Publication

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiac disorder characterized by sodium channel dysfunction. However,the clinical management of ARVC remains challenging. Identifying novel compounds for the treatment of ARVC is crucial for advancing drug development.PurposeIn this study,we aim to identify novel compounds for treating ARVC.MethodsMachine learning (ML) models were constructed using proteins analyzed from the scRNA-seq data of ARVC rats and their corresponding protein-protein interaction (PPI) network to predict binding affinity (BA). To validate these predictions,a series of experiments in cardiac organoids were conducted,including Western blotting,ELISA,MEA,and Masson staining to assess the effects of these compounds.ResultsWe first discovered and identified SCN5A as the most significantly affected sodium channel protein in ARVC. ML models predicted that Kaempferol binds to SCN5A with high affinity. In vitro experiments further confirmed that Kaempferol exerted therapeutic effects in ARVC.ConclusionThis study presents a novel approach for identifying potential compounds to treat ARVC. By integrating ML modeling with organoid validation,our platform provides valuable support in addressing the public health challenges posed by ARVC,with broad application prospects. Kaempferol shows promise as a lead compound for ARVC treatment. View Publication

Cell replacement therapy is a promising therapeutic option for dry age-related macular degeneration (AMD). In this study,we outline our design for scalable manufacture with appropriate quality gates and present in vivo data for establishing preclinical safety and efficacy of an induced pluripotent stem cell (iPSC)-derived retinal pigment epithelium (RPE) product,thus laying the foundation for Phase 1/2a trial approval in India (ClinicalTrials.gov ID: NCT06394232; date of registration: 23rd September 2024). Escalating doses of RPE cell suspension in immunocompromised animals demonstrated absence of tumor formation up to 9?months post-injection. Good Laboratory Practices (GLP) toxicology and tolerability studies in rabbits and non-human primates (NHP) respectively showed no major adverse events. RPE transplanted into immune suppressed RCS rats showed integration,neuroprotection and rescue of visual function. In addition,we provide a detailed description of the modifications in GMP manufacturing protocol to create a final product with a unique composition and Chemistry,Manufacturing and Controls (CMC) studies performed during product development. View Publication

TOP2 inhibitors (TOP2i) are effective drugs for breast cancer treatment. However,they can cause cardiotoxicity in some women. The most widely used TOP2i include anthracyclines (AC) Doxorubicin (DOX),Daunorubicin (DNR),Epirubicin (EPI),and the anthraquinone Mitoxantrone (MTX). It is unclear whether women would experience the same adverse effects from all drugs in this class,or if specific drugs would be preferable for certain individuals based on their cardiotoxicity risk profile. To investigate this,we studied the effects of treatment of DOX,DNR,EPI,MTX,and an unrelated monoclonal antibody Trastuzumab (TRZ) on iPSC-derived cardiomyocytes (iPSC-CMs) from six healthy females. All TOP2i induce cell death at concentrations observed in cancer patient serum,while TRZ does not. A sub-lethal dose of all TOP2i induces limited cellular stress but affects calcium handling,a function critical for cardiomyocyte contraction. TOP2i induce thousands of gene expression changes over time,giving rise to four distinct gene expression response signatures,denoted as TOP2i early-acute,early-sustained,and late response genes,and non-response genes. There is no drug- or AC-specific signature. TOP2i early response genes are enriched in chromatin regulators,which mediate AC sensitivity across breast cancer patients. However,there is increased transcriptional variability between individuals following AC treatments. To investigate potential genetic effects on response variability,we first identified a reported set of expression quantitative trait loci (eQTLs) uncovered following DOX treatment in iPSC-CMs. Indeed,DOX response eQTLs are enriched in genes that respond to all TOP2i. Next,we identified 38 genes in loci associated with AC toxicity by GWAS or TWAS. Two thirds of the genes that respond to at least one TOP2i,respond to all ACs with the same direction of effect. Our data demonstrate that TOP2i induce thousands of shared gene expression changes in cardiomyocytes,including genes near SNPs associated with inter-individual variation in response to DOX treatment and AC-induced cardiotoxicity. Author summaryAnthracycline drugs such as Doxorubicin are effective treatments for breast cancer; however,they can cause cardiotoxicity in some women. It is unclear whether women would experience the same toxicity for all drugs in this class,or whether specific drugs would be better tolerated in specific individuals. We used an in vitro system of induced pluripotent stem cell-derived cardiomyocytes from six healthy females to test the effects of five breast cancer drugs on cell heath and global gene expression. We identified a strong shared cellular and gene expression response to drugs from the same class. However,there is more variation in gene expression levels between individuals following treatment with each anthracycline compared to untreated cells. We found that many genes in regions previously associated with Doxorubicin-induced cardiotoxicity in cancer patients,respond to at least two drugs in the class. This suggests that drugs in the same class induce similar effects on an individual’s heart. This work contributes to our understanding of how drug response,in the context of off-target effects,varies across individuals. View Publication

How paracrine signals are interpreted to yield multiple cell fate decisions in a dynamic context during human development in vivo and in vitro remains poorly understood. Here we report an automated tracking method to follow signaling histories linked to cell fate in large numbers of human pluripotent stem cells (hPSCs). Using an unbiased statistical approach,we discover that measured BMP signaling history correlates strongly with fate in individual cells. We find that BMP response in hPSCs varies more strongly in the duration of signaling than the level. However,both the level and duration of signaling activity control cell fate choices only by changing the time integral. Therefore,signaling duration and level are interchangeable in this context. In a stem cell model for patterning of the human embryo,we show that signaling histories predict the fate pattern and that the integral model correctly predicts changes in cell fate domains when signaling is perturbed. Our data suggest that mechanistically,BMP signaling is integrated by SOX2. The interpretation of the key developmental signal BMP remains poorly understood. Here,the authors show that the total time-integrated signaling controls differentiation in a stem cell embryo model and provide a possible mechanism. View Publication

Quantum dots,which won the Nobel Prize in Chemistry,have recently gained significant attention in precision medicine due to their unique properties,such as size-tunable emission,high photostability,efficient light absorption,and vibrant luminescence. Consequently,there is a growing demand to identify new types of quantum dots from various sources and explore their potential applications as stimuli-responsive biosensors,biomolecular imaging probes,and targeted drug delivery agents. Biomass-waste-derived carbon quantum dots (CQDs) are an attractive alternative to conventional QDs,which often require expensive and toxic precursors,as they offer several merits in eco-friendly synthesis,preparation from renewable sources,and cost-effective production. In this study,we evaluated three CQDs derived from biomass waste for their potential application as non-toxic bioimaging agents in various cell lines,including human dermal fibroblasts,HeLa,cardiomyocytes,induced pluripotent stem cells,and an in-vivo medaka fish (Oryzias latipes) model. Confocal microscopic studies revealed that CQDs could assist in visualizing inflammatory processes in the cells,as they were taken up more by cells treated with tumor necrosis factor-? than untreated cells. In addition,our quantitative real-time PCR gene expression analysis has revealed that citric acid-based CQDs can potentially reduce inflammatory markers such as Interleukin-6. Our studies suggest that CQDs have potential as theragnostic agents,which can simultaneously identify and modulate inflammatory markers and may lead to targeted therapy for immune system-associated diseases. View Publication

SummaryFocusing on the early stages of Alzheimer’s disease (AD) holds great promise. However,the specific events in neural cells preceding AD onset remain elusive. To address this,we utilized human-induced pluripotent stem cells carrying APPswe mutation to explore the initial changes associated with AD progression. We observed enhanced neural activity and early neuronal differentiation in APPswe cerebral organoids cultured for one month. This phenomenon was also evident when neural progenitor cells (NPCs) were differentiated into neurons. Furthermore,transcriptomic analyses of NPCs and neurons confirmed altered expression of neurogenesis-related genes in APPswe NPCs. We also found that the upregulation of reactive oxygen species (ROS) is crucial for early neuronal differentiation in these cells. In addition,APPswe neurons remained immature after initial differentiation with increased susceptibility to toxicity,providing valuable insights into the premature exit from the neural progenitor state and the increased vulnerability of neural cells in AD. Graphical abstract Highlights•APPswe organoids show increased neural activity and early differentiation•Enhanced ROS levels are necessary but insufficient to accelerate differentiation•Transcriptome analysis of APPswe NPCs shows gene expression shift to differentiation•Premature neural cells with APPswe exhibit increased vulnerability to toxicity Molecular biology; Neuroscience; Cell biology View Publication

Human embryonic stem cells (hESCs) serve as a valuable in vitro model for studying early human developmental processes due to their ability to differentiate into all three germ layers. Here,we present a comprehensive multi-omics dataset generated by differentiating hESCs into cardiomyocytes via the mesodermal lineage,collecting samples at 10 distinct time points. We measured mRNA levels by mRNA sequencing (mRNA-seq),translation levels by ribosome profiling (Ribo-seq),and protein levels by quantitative mass spectrometry-based proteomics. Technical validation confirmed high quality and reproducibility across all datasets,with strong correlations between replicates. This extensive dataset provides critical insights into the complex regulatory mechanisms of cardiomyocyte differentiation and serves as a valuable resource for the research community,aiding in the exploration of mammalian development and gene regulation. View Publication