Chromatin interaction maps of human arterioles reveal mechanisms for the genetic regulation of blood pressure
Arterioles are small blood vessels located just upstream of capillaries in nearly all tissues. Despite the broad and essential role of arterioles in physiology and disease,current knowledge of the functional genomics of arterioles is largely absent. Here,we report extensive maps of chromatin interactions,single-cell expression,and other molecular features in human arterioles and uncover mechanisms linking human genetic variants to gene expression in vascular cells and the development of hypertension. Compared to large arteries,arterioles exhibited a higher proportion of pericytes which were enriched for blood pressure (BP)-associated genes. BP-associated single nucleotide polymorphisms (SNPs) were enriched in chromatin interaction regions in arterioles. We linked BP-associated noncoding SNP rs1882961 to gene expression through long-range chromatin contacts and revealed remarkable effects of a 4-bp noncoding genomic segment on hypertension in vivo. We anticipate that our data and findings will advance the study of the numerous diseases involving arterioles. Liu et al.,report extensive maps of chromatin interactions,single-cell expression,and other molecular features in human arterioles and uncover mechanisms linking noncoding genetic variants to gene expression and the development of hypertension.
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(Jun 2025)
Clinical and Translational Medicine 15 6
OXA1L deficiency causes mitochondrial myopathy via reactive oxygen species regulated nuclear factor kappa B signalling pathway
AbstractBackgroundOXA1L is crucial for mitochondrial protein insertion and assembly into the inner mitochondrial membrane,and its variants have been recently linked to mitochondrial encephalopathy. However,the definitive pathogenic link between OXA1L variants and mitochondrial diseases as well as the underlying pathogenesis remains elusive.MethodsIn this study,we identified bi?allelic variants of c.620G>T,p.(Cys207Phe) and c.1163_1164del,p.(Val388Alafs*15) in OXA1L gene in a mitochondrial myopathy patient using whole exome sequencing. To unravel the genotype–phenotype relationship and underlying pathogenic mechanism between OXA1L variants and mitochondrial diseases,patient?specific human?induced pluripotent stem cells (hiPSC) were reprogrammed and differentiated into myotubes,while OXA1L knockout human immortalised skeletal muscle cells (IHSMC) and a conditional skeletal muscle knockout mouse model was generated using clustered regularly interspaced short palindromic repeats/Cas9 genomic editing technology.ResultsBoth patient?specific hiPSC differentiated myotubes and OXA1L knockout IHSMC showed combined mitochondrial respiratory chain defects and oxidative phosphorylation (OXPHOS) impairments. Notably,in OXA1L?knockout IHSMC,transfection of wild?type human OXA1L but not truncated mutant form rescued the respiratory chain defects. Moreover,skeletal muscle conditional Oxa1l knockout mice exhibited OXPHOS deficiencies and skeletal muscle morphofunctional abnormalities,recapitulating the phenotypes of mitochondrial myopathy. Further functional investigations revealed that impaired OXPHOS resulting of OXA1L deficiency led to elevated reactive oxygen species production,which possibly activated the nuclear factor kappa B signalling pathway,triggering cell apoptosis.ConclusionsTogether,our findings reinforce the genotype–phenotype association between OXA1L variations and mitochondrial diseases and further delineate the potential molecular mechanisms of how OXA1L deficiency causes skeletal muscle deficits in mitochondrial myopathy.
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(Jan 2025)
Cell Death & Disease 16 1
Endothelial-Ercc1 DNA repair deficiency provokes blood-brain barrier dysfunction
Aging of the brain vasculature plays a key role in the development of neurovascular and neurodegenerative diseases,thereby contributing to cognitive impairment. Among other factors,DNA damage strongly promotes cellular aging,however,the role of genomic instability in brain endothelial cells (EC) and its potential effect on brain homeostasis is still largely unclear. We here investigated how endothelial aging impacts blood-brain barrier (BBB) function by using excision repair cross complementation group 1 (ERCC1)-deficient human brain ECs and an EC-specific Ercc1 knock out (EC-KO) mouse model. In vitro,ERCC1-deficient brain ECs displayed increased senescence-associated secretory phenotype expression,reduced BBB integrity,and higher sprouting capacities due to an underlying dysregulation of the Dll4-Notch pathway. In line,EC-KO mice showed more P21+ cells,augmented expression of angiogenic markers,and a concomitant increase in the number of brain ECs and pericytes. Moreover,EC-KO mice displayed BBB leakage and enhanced cell adhesion molecule expression accompanied by peripheral immune cell infiltration into the brain. These findings were confined to the white matter,suggesting a regional susceptibility. Collectively,our results underline the role of endothelial aging as a driver of impaired BBB function,endothelial sprouting,and increased immune cell migration into the brain,thereby contributing to impaired brain homeostasis as observed during the aging process.
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(Sep 2024)
Stem Cell Research & Therapy 15 8
Prostatic lineage differentiation from human embryonic stem cells through inducible expression of NKX3-1
BackgroundUnderstanding the lineage differentiation of human prostate not only is crucial for basic research on human developmental biology but also significantly contributes to the management of prostate-related disorders. Current knowledge mainly relies on studies on rodent models,lacking human-derived alternatives despite clinical samples may provide a snapshot at certain stage. Human embryonic stem cells can generate all the embryonic lineages including the prostate,and indeed a few studies demonstrate such possibility based on co-culture or co-transplantation with urogenital mesenchyme into mouse renal capsule.MethodsTo establish a stepwise protocol to obtain prostatic organoids in vitro from human embryonic stem cells,we apply chemicals and growth factors by mimicking the regulation network of transcription factors and signal transduction pathways,and construct cell lines carrying an inducible NKX3-1 expressing cassette,together with three-dimensional culture system. Unpaired t test was applied for statistical analyses.ResultsWe first successfully generate the definitive endoderm,hindgut,and urogenital sinus cells. The embryonic stem cell-derived urogenital sinus cells express prostatic key transcription factors AR and FOXA1,but fail to express NKX3-1. Therefore,we construct NKX3-1-inducible cell line by homologous recombination,which is eventually able to yield AR,FOXA1,and NKX3-1 triple-positive urogenital prostatic lineage cells through stepwise differentiation. Finally,combined with 3D culture we successfully derive prostate-like organoids with certain structures and prostatic cell populations.ConclusionsThis study reveals the crucial role of NKX3-1 in prostatic differentiation and offers the inducible NKX3-1 cell line,as well as provides a stepwise differentiation protocol to generate human prostate-like organoids,which should facilitate the studies on prostate development and disease pathogenesis.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13287-024-03886-y.
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(Sep 2024)
Cell Reports Methods 4 9
Fully defined NGN2 neuron protocol reveals diverse signatures of neuronal maturation
SummaryNGN2-driven induced pluripotent stem cell (iPSC)-to-neuron conversion is a popular method for human neurological disease modeling. In this study,we present a standardized approach for generating neurons utilizing clonal,targeted-engineered iPSC lines with defined reagents. We demonstrate consistent production of excitatory neurons at scale and long-term maintenance for at least 150 days. Temporal omics,electrophysiological,and morphological profiling indicate continued maturation to postnatal-like neurons. Quantitative characterizations through transcriptomic,imaging,and functional assays reveal coordinated actions of multiple pathways that drive neuronal maturation. We also show the expression of disease-related genes in these neurons to demonstrate the relevance of our protocol for modeling neurological disorders. Finally,we demonstrate efficient generation of NGN2-integrated iPSC lines. These workflows,profiling data,and functional characterizations enable the development of reproducible human in vitro models of neurological disorders. Graphical abstract Highlights•Optimized NGN2 protocol generates functional postnatal neurons in 28 days•Extensive profiling data provide benchmarks for neuron maturation•Maturation assays reliably assess neuron maturation in single or mixed cell types•Rapid targeted engineering protocol integrates NGN2 into iPSC lines in 3 weeks MotivationUsing induced pluripotent stem cell (iPSC)-derived neurons (iNs) to model diseases requires defined,robust,and reproducible protocols capable of generating predictable neuronal types. In addition,extensive profiling is essential to assess whether iNs are suitable to model specific diseases with desired molecular,functional,and maturation-related features. We sought to establish a standardized protocol for generating iNs at large scales. We also sought to develop systematic profiling data and assays for determining the maturation levels of iN cultures as resources for the community. Shan et al. report methods to generate postnatal-like iPSC-derived neurons at large scale and with long-term stability. They provide extensive characterization data and assays to measure neuronal maturity. They find genes associated with maturation exhibit diverse functions. Their data support the utility of these methods to enable modeling of neurological disorders.
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(Sep 2024)
Human Genetics and Genomics Advances 5 4
Non-coding cause of congenital heart defects: Abnormal RNA splicing with multiple isoforms as a mechanism for heterotaxy
SummaryHeterotaxy is a disorder characterized by severe congenital heart defects (CHDs) and abnormal left-right patterning in other thoracic or abdominal organs. Clinical and research-based genetic testing has previously focused on evaluation of coding variants to identify causes of CHDs,leaving non-coding causes of CHDs largely unknown. Variants in the transcription factor zinc finger of the cerebellum 3 (ZIC3) cause X-linked heterotaxy. We identified an X-linked heterotaxy pedigree without a coding variant in ZIC3. Whole-genome sequencing revealed a deep intronic variant (ZIC3 c.1224+3286A>G) predicted to alter RNA splicing. An in vitro minigene splicing assay confirmed the variant acts as a cryptic splice acceptor. CRISPR-Cas9 served to introduce the ZIC3 c.1224+3286A>G variant into human embryonic stem cells demonstrating pseudoexon inclusion caused by the variant. Surprisingly,Sanger sequencing of the resulting ZIC3 c.1224+3286A>G amplicons revealed several isoforms,many of which bypass the normal coding sequence of the third exon of ZIC3,causing a disruption of a DNA-binding domain and a nuclear localization signal. Short- and long-read mRNA sequencing confirmed these initial results and identified additional splicing patterns. Assessment of four isoforms determined abnormal functions in vitro and in vivo while treatment with a splice-blocking morpholino partially rescued ZIC3. These results demonstrate that pseudoexon inclusion in ZIC3 can cause heterotaxy and provide functional validation of non-coding disease causation. Our results suggest the importance of non-coding variants in heterotaxy and the need for improved methods to identify and classify non-coding variation that may contribute to CHDs. Coding variants in the transcription factor ZIC3 cause X-linked heterotaxy,a laterality defect causing congenital anomalies. Functional genomic analyses of a ZIC3 intronic variant identified in an X-linked heterotaxy pedigree demonstrated pseudoexon inclusion leading to RNA-splicing disruption,highlighting the importance of whole-genome sequencing to identify potential disease-causing variants.
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(Apr 2025)
Frontiers in Genome Editing 7
Efficient GBA1 editing via HDR with ssODNs by outcompeting pseudogene-mediated gene conversion upon CRISPR/Cas9 cleavage
IntroductionCRISPR/Cas9-edited induced pluripotent stem cells (iPSCs) are valuable research models for mechanistic studies. However,gene conversion between a gene-pseudogene pair that share high sequence identity and form direct repeats in proximity on the same chromosome can interfere with the precision of gene editing. Mutations in the human beta-glucocerebrosidase gene (GBA1) are associated with Gaucher disease,Parkinson’s disease,and Lewy body dementia. During the creation of a GBA1 KO iPSC line,we detected about 70% gene conversion from its pseudogene GBAP1. These events maintained the reading frame and resulted from GBA1-specific cleavage by CRISPR/Cas9,without disrupting the GBA1 gene.MethodTo increase the percentage of alleles with out-of-frame indels for triggering nonsense-mediated decay of the GBA1 mRNA,we supplied the cells with two single-stranded oligodeoxynucleotide (ssODN) donors as homology-directed repair (HDR) templates.ResultsWe demonstrate that HDR using the ssODN templates effectively competes with gene conversion and enabled biallelic KO clone isolation,whereas the nonallelic homologous recombination (NAHR)-based deletion rate remained the same.DiscussionHere,we report a generalizable method to direct cellular DNA repair of double strand breaks at a target gene towards the HDR pathway using exogenous ssODN templates,allowing specific editing of one gene in a gene-pseudogene pair without disturbing the other.
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(Apr 2025)
Journal of Neuroinflammation 22 7341
Microglia determine an immune-challenged environment and facilitate ibuprofen action in human retinal organoids
Prenatal immune challenges pose significant risks to human embryonic brain and eye development. However,our knowledge about the safe usage of anti-inflammatory drugs during pregnancy is still limited. While human induced pluripotent stem cells (hIPSC)-derived brain organoid models have started to explore functional consequences upon viral stimulation,these models commonly lack microglia,which are susceptible to and promote inflammation. Furthermore,microglia are actively involved in neuronal development. Here,we generate hIPSC-derived microglia precursor cells and assemble them into retinal organoids. Once the outer plexiform layer forms,these hIPSC-derived microglia (iMG) fully integrate into the retinal organoids. Since the ganglion cell survival declines by this time in 3D-retinal organoids,we adapted the model into 2D and identify that the improved ganglion cell number significantly decreases only with iMG presence. In parallel,we applied the immunostimulant POLY(I:C) to mimic a fetal viral infection. While POLY(I:C) exposure alters the iMG phenotype,it does not hinder their interaction with ganglion cells. Furthermore,iMG significantly enhance the supernatant’s inflammatory secretome and increase retinal cell proliferation. Simultaneous exposure with the non-steroidal anti-inflammatory drug (NSAID) ibuprofen dampens POLY(I:C)-mediated changes of the iMG phenotype and ameliorates cell proliferation. Remarkably,while POLY(I:C) disrupts neuronal calcium dynamics independent of iMG,ibuprofen rescues this effect only if iMG are present. Mechanistically,ibuprofen targets the enzymes cyclooxygenase 1 and 2 (COX1/PTGS1 and COX2/PTGS2) simultaneously,from which iMG mainly express COX1. Selective COX1 blockage fails to restore the calcium peak amplitude upon POLY(I:C) stimulation,suggesting ibuprofen’s beneficial effect depends on the presence and interplay of COX1 and COX2. These findings underscore the importance of microglia in the context of prenatal immune challenges and provide insight into the mechanisms by which ibuprofen exerts its protective effects during embryonic development.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12974-025-03366-x.
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(Sep 2024)
Molecular Autism 15 8
Identifying SETBP1 haploinsufficiency molecular pathways to improve patient diagnosis using induced pluripotent stem cells and neural disease modelling
BackgroundSETBP1 Haploinsufficiency Disorder (SETBP1-HD) is characterised by mild to moderate intellectual disability,speech and language impairment,mild motor developmental delay,behavioural issues,hypotonia,mild facial dysmorphisms,and vision impairment. Despite a clear link between SETBP1 mutations and neurodevelopmental disorders the precise role of SETBP1 in neural development remains elusive. We investigate the functional effects of three SETBP1 genetic variants including two pathogenic mutations p.Glu545Ter and SETBP1 p.Tyr1066Ter,resulting in removal of SKI and/or SET domains,and a point mutation p.Thr1387Met in the SET domain.MethodsGenetic variants were introduced into induced pluripotent stem cells (iPSCs) and subsequently differentiated into neurons to model the disease. We measured changes in cellular differentiation,SETBP1 protein localisation,and gene expression changes.ResultsThe data indicated a change in the WNT pathway,RNA polymerase II pathway and identified GATA2 as a central transcription factor in disease perturbation. In addition,the genetic variants altered the expression of gene sets related to neural forebrain development matching characteristics typical of the SETBP1-HD phenotype.LimitationsThe study investigates changes in cellular function in differentiation of iPSC to neural progenitor cells as a human model of SETBP1 HD disorder. Future studies may provide additional information relevant to disease on further neural cell specification,to derive mature neurons,neural forebrain cells,or brain organoids.ConclusionsWe developed a human SETBP1-HD model and identified perturbations to the WNT and POL2RA pathway,genes regulated by GATA2. Strikingly neural cells for both the SETBP1 truncation mutations and the single nucleotide variant displayed a SETBP1-HD-like phenotype.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13229-024-00625-1.
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(Jul 2024)
Molecular Metabolism 88 12
Tissue Inhibitor of Metalloproteinase 3 (TIMP3) mutations increase glycolytic activity and dysregulate glutamine metabolism in RPE cells
ObjectivesMutations in Tissue Inhibitor of Metalloproteinases 3 (TIMP3) cause Sorsby's Fundus Dystrophy (SFD),a dominantly inherited,rare form of macular degeneration that results in vision loss. TIMP3 is synthesized primarily by retinal pigment epithelial (RPE) cells,which constitute the outer blood-retinal barrier. One major function of RPE is the synthesis and transport of vital nutrients,such as glucose,to the retina. Recently,metabolic dysfunction in RPE cells has emerged as an important contributing factor in retinal degenerations. We set out to determine if RPE metabolic dysfunction was contributing to SFD pathogenesis.MethodsQuantitative proteomics was conducted on RPE of mice expressing the S179C variant of TIMP3,known to be causative of SFD in humans. Proteins found to be differentially expressed (P < 0.05) were analyzed using statistical overrepresentation analysis to determine enriched pathways,processes,and protein classes using g:profiler and PANTHER Gene Ontology. We examined the effects of mutant TIMP3 on RPE metabolism using human ARPE-19 cells expressing mutant S179C TIMP3 and patient-derived induced pluripotent stem cell-derived RPE (iRPE) carrying the S204C TIMP3 mutation. RPE metabolism was directly probed using isotopic tracing coupled with GC/MS analysis. Steady state [U–13C6] glucose isotopic tracing was preliminarily conducted on S179C ARPE-19 followed by [U–13C6] glucose and [U–13C5] glutamine isotopic tracing in SFD iRPE cells.ResultsQuantitative proteomics and enrichment analysis conducted on RPE of mice expressing mutant S179C TIMP3 identified differentially expressed proteins that were enriched for metabolism-related pathways and processes. Notably these results highlighted dysregulated glycolysis and glucose metabolism. Stable isotope tracing experiments with [U–13C6] glucose demonstrated enhanced glucose utilization and glycolytic activity in S179C TIMP3 APRE-19 cells. Similarly,[U–13C6] glucose tracing in SFD iRPE revealed increased glucose contribution to glycolysis and the TCA cycle. Additionally,[U–13C5] glutamine tracing found evidence of altered malic enzyme activity.ConclusionsThis study provides important information on the dysregulation of RPE glucose metabolism in SFD and implicates a potential commonality with other retinal degenerative diseases,emphasizing RPE cellular metabolism as a therapeutic target. Highlights•SFD mice display alterations in proteins associated with metabolism.•SFD RPE cells have increased glycolytic activity and glucose contribution to the TCA cycle.•Glutamine contribution to energy metabolism is unaltered in SFD RPE cells however there is reduced malic enzyme activity.•SFD RPE cells display metabolic dysfunction potentially implicating metabolism as a viable therapeutic target.
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(Nov 2024)
Nature Communications 15
Constructing organoid-brain-computer interfaces for neurofunctional repair after brain injury
The reconstruction of damaged neural circuits is critical for neurological repair after brain injury. Classical brain-computer interfaces (BCIs) allow direct communication between the brain and external controllers to compensate for lost functions. Importantly,there is increasing potential for generalized BCIs to input information into the brains to restore damage,but their effectiveness is limited when a large injured cavity is caused. Notably,it might be overcome by transplantation of brain organoids into the damaged region. Here,we construct innovative BCIs mediated by implantable organoids,coined as organoid-brain-computer interfaces (OBCIs). We assess the prolonged safety and feasibility of the OBCIs,and explore neuroregulatory strategies. OBCI stimulation promotes progressive differentiation of grafts and enhances structural-functional connections within organoids and the host brain,promising to repair the damaged brain via regenerating and regulating,potentially directing neurons to preselected targets and recovering functional neural networks in the future. Damaged neural circuits could be improved by generalized BCIs via inputting information into the brains,which is restricted when a large injured cavity caused. Here,the authors construct BCIs mediated by organoid grafts to repair the damaged brain
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(Jun 2024)
Molecular Therapy. Methods & Clinical Development 32 3
Engineering single-cycle MeV vector for CRISPR-Cas9 gene editing
CRISPR-Cas9-mediated gene editing has vast applications in basic and clinical research and is a promising tool for several disorders. Our lab previously developed a non-integrating RNA virus,measles virus (MeV),as a single-cycle reprogramming vector by replacing the viral attachment protein with the reprogramming factors for induced pluripotent stem cell generation. Encouraged by the MeV reprogramming vector efficiency,in this study,we develop a single-cycle MeV vector to deliver the gRNA(s) and Cas9 nuclease to human cells for efficient gene editing. We show that the MeV vector achieved on-target gene editing of the reporter (mCherry) and endogenous genes (HBB and FANCD1) in human cells. Additionally,the MeV vector achieved precise knock-in via homology-directed repair using a single-stranded oligonucleotide donor. The MeV vector is a new and flexible platform for gene knock-out and knock-in modifications in human cells,capable of incorporating new technologies as they are developed. Graphical abstract Devaux and colleagues developed a novel single-cycle measles vector allowing gene editing of human cells. They show that Measles can express the CRISPR-Cas9 and gRNA from one genome. Finally,they demonstrate that these vectors can efficiently perform KO and knock-in in human cells without excessive off-target effects.
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