技术资料

The faithful segregation of intact genetic material and the perpetuation of chromatin states through mitotic cell divisions are pivotal for maintaining cell function and identity across cell generations. However,most exogenous mutagens generate long-lasting DNA lesions that are segregated during mitosis. How this segregation is controlled is unknown. Here,we uncover a mitotic chromatin-marking pathway that governs the segregation of UV-induced damage in human cells. Our mechanistic analyses reveal two layers of control: histone ADP-ribosylation,and the incorporation of newly synthesized histones at UV damage sites,that both prevent local mitotic phosphorylations on histone H3 serine residues. Functionally,this chromatin-marking pathway controls the segregation of UV damage in the cell progeny with consequences on daughter cell fate. We propose that this mechanism may help preserve the integrity of stem cell compartments during asymmetric cell divisions. The transmission of unrepaired DNA lesions through mitosis needs tight control. Here,the authors uncover a damaged chromatin marking mechanism driving the segregation of UV damage through mitosis with potential consequences on daughter cell fate. View Publication

AbstractBackgroundRodent models have been widely used to investigate skin development,but do not account for significant differences in composition compared to human skin. On the other hand,two-dimensional and three-dimensional engineered skin models still lack the complex features of human skin such as appendages and pigmentation. Recently,hair follicle containing skin organoids (SKOs) with a stratified epidermis,and dermis layer have been generated as floating spheres from human-induced pluripotent stem cells (hiPSCs).MethodsThe current study aims to investigate the generation of hiPSCs-derived SKOs using an air-liquid interface (ALI) model on transwell membranes (T-SKOs) and compares their development with conventional floating culture in low-attachment plates (F-SKOs).ResultsMature SKOs containing an epidermis,dermis,and appendages are created in both T-SKO and F-SKO conditions. It was found that the hair follicles are smaller and shorter in the F-SKO compared with T-SKOs. Additionally,the ALI conditions contribute to enhanced hair follicle numbers than conventional floating culture.ConclusionsTogether,this study demonstrates the significant influence of transwell culture on the morphogenesis of hair follicles within SKOs and highlights the potential for refinement of skin model engineering for advancing dermatology and skin research. View Publication

Cryopreservation in cryovials extends cell storage at low temperatures,and advances in organoid cryopreservation improve reproducibility and reduce generation time. However,cryopreserving human organoids presents challenges due to the limited diffusion of cryoprotective agents (CPAs) into the organoid core and the potential toxicity of these agents. To overcome these obstacles,we developed a cryopreservation technique using a pillar plate platform. To illustrate cryopreservation application to human brain organoids (HBOs),early-stage HBOs were produced by differentiating induced pluripotent stem cells (iPSCs) into neuroectoderm (NEs) in an ultralow atachement (ULA) 384-well plate. These NEs were transferred and encapsulated in Matrigel on the pillar plate. The early-stage HBOs on the pillar plate were exposed to four commercially available CPAs,including PSC cryopreservation kit,CryoStor CS10,3dGRO,and 10% DMSO,before being frozen overnight at ?80°C and subsequently stored in a liquid nitrogen dewar. We examined the impact of CPA type,organoid size,and CPA exposure duration on cell viability post-thaw. Additionally,the differentiation of early-stage HBOs on the pillar plate was assessed using RT-qPCR and immunofluorescence staining. The PSC cryopreservation kit proved to be the least toxic for preserving these HBOs on the pillar plate. Notably,smaller HBOs showed higher cell viability post-cryopreservation than larger ones. An incubation period of 80 minutes with the PSC kit was essential to ensure optimal CPA diffusion into HBOs with a diameter of 400 – 600 ?m. These cryopreserved early-stage HBOs successfully matured over 30 days,exhibiting gene expression patterns akin to non-cryopreserved HBOs. The cryopreserved early-stage HBOs on the pillar plate maintained high viability after thawing and successfully differentiated into mature HBOs. This on-chip cryopreservation method could extend to other small organoids,by integrating cryopreservation,thawing,culturing,staining,rinsing,and imaging processes within a single system,thereby preserving the 3D structure of the organoids. View Publication

Enhancing RuvBL1,but particularly RuvBL2 expression,reduces toxic dipeptide repeat proteins in vitro and in vivo models of C9orf72-linked ALS/FTD,suggesting that modulating RuvBL1/2 levels could be a promising therapeutic approach for C9ALS/FTD. A G4C2 hexanucleotide repeat expansion in C9orf72 is the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Bidirectional transcription and subsequent repeat-associated non-AUG (RAN) translation of sense and antisense transcripts leads to the formation of five dipeptide repeat (DPR) proteins. These DPRs are toxic in a wide range of cell and animal models. Therefore,decreasing RAN-DPRs may be of therapeutic benefit in the context of C9ALS/FTD. In this study,we found that C9ALS/FTD patients have reduced expression of the AAA+ family members RuvBL1 and RuvBL2,which have both been implicated in aggregate clearance. We report that overexpression of RuvBL1,but to a greater extent RuvBL2,reduced C9orf72-associated DPRs in a range of in vitro systems including cell lines,primary neurons from the C9-500 transgenic mouse model,and patient-derived iPSC motor neurons. In vivo,we further demonstrated that RuvBL2 overexpression and consequent DPR reduction in our Drosophila model was sufficient to rescue a number of DPR-related motor phenotypes. Thus,modulating RuvBL levels to reduce DPRs may be of therapeutic potential in C9ALS/FTD. View Publication

This study describes an OTULIN-related autoinflammatory syndrome (ORAS) patient with two rare heterozygous variants of OTULIN (p.P152L and p.R306Q); the latter is a de novo variant that acts in a dominant-negative manner to cause ORAS. OTULIN-related autoinflammatory syndrome (ORAS),a severe autoinflammatory disease,is caused by biallelic pathogenic variants of OTULIN,a linear ubiquitin-specific deubiquitinating enzyme. Loss of OTULIN attenuates linear ubiquitination by inhibiting the linear ubiquitin chain assembly complex (LUBAC). Here,we report a patient who harbors two rare heterozygous variants of OTULIN (p.P152L and p.R306Q). We demonstrated accumulation of linear ubiquitin chains upon TNF stimulation and augmented TNF-induced cell death in mesenchymal stem cells differentiated from patient-derived iPS cells,which confirms that the patient has ORAS. However,although the de novo p.R306Q variant exhibits attenuated deubiquitination activity without reducing the amount of OTULIN,the deubiquitination activity of the p.P152L variant inherited from the mother was equivalent to that of the wild-type. Patient-derived MSCs in which the p.P152L variant was replaced with wild-type also exhibited augmented TNF-induced cell death and accumulation of linear chains. The finding that ORAS can be caused by a dominant-negative p.R306Q variant of OTULIN furthers our understanding of disease pathogenesis. Graphical Abstract View Publication

ABSTRACTDuchenne muscular dystrophy (DMD) is a progressive muscle wasting disorder affecting 1:3500 male births and is associated with myofiber degeneration,regeneration,and inflammation. Glucocorticoid treatments have been the standard of care due to immunomodulatory/immunosuppressive properties but novel genetic approaches,including exon skipping and gene replacement therapy,are currently being developed. The identification of additional biomarkers to assess DMD-related inflammatory responses and the potential efficacy of these therapeutic approaches are thus of critical importance. The current study uses RNA sequencing of skeletal muscle from two mdx mouse models to identify high mobility group box 1 (HMGB1) as a candidate biomarker potentially contributing to DMD-related inflammation. HMGB1 protein content was increased in a human iPSC-derived skeletal myocyte model of DMD and microdystrophin treatment decreased HMGB1 back to control levels. In vivo,HMGB1 protein levels were increased in vehicle treated B10-mdx skeletal muscle compared to B10-WT and significantly decreased in B10-mdx animals treated with adeno-associated virus (AAV)-microdystrophin. However,HMGB1 protein levels were not increased in D2-mdx skeletal muscle compared to D2-WT,demonstrating a strain-specific difference in DMD-related immunopathology. Summary: Duchenne muscular dystrophy is a devastating that currently has limited treatment options. RNA sequencing and downstream analysis in iSkM and mdx samples revealed HMGB1 may be a relevant treatment biomarker. View Publication

Blood transfusion plays a vital role in modern medicine,but frequent shortages occur. Ex vivo manufacturing of red blood cells (RBCs) from universal donor cells offers a potential solution,yet the high cost of recombinant cytokines remains a barrier. Erythropoietin (EPO) signaling is crucial for RBC development,and EPO is among the most expensive media components. To address this challenge,we develop highly optimized small molecule-inducible synthetic EPO receptors (synEPORs) using design-build-test cycles and genome editing. By integrating synEPOR at the endogenous EPOR locus in O-negative induced pluripotent stem cells,we achieve equivalent erythroid differentiation,transcriptomic changes,and hemoglobin production using small molecules compared to EPO-supplemented cultures. This approach dramatically reduces culture media costs. Our strategy not only addresses RBC production challenges but also demonstrates how protein and genome engineering can introduce precisely regulated cellular behaviors,potentially improving scalable manufacturing of a wide range of clinically relevant cell types. Shortages of donor blood for transfusions can have severe medical consequences,and ex vivo production of red blood cells offers a potential solution. Here authors developed synthetic EPO receptors,which allow erythropoiesis (red blood cell production) without the need for expensive EPO. View Publication

Cell-autonomous barriers to reprogramming somatic cells into induced pluripotent stem cells (iPSCs) remain poorly understood. Using a focused CRISPR-Cas9 screen,we identified Ubiquitin-specific peptidase 22 (USP22) as a key chromatin-based barrier to human iPSC derivation. Suppression of USP22 significantly enhances reprogramming efficiency. Surprisingly,this effect is likely to be independent of USP22’s deubiquitinase activity or its association with the SAGA complex,as shown through module-specific knockouts,and genetic rescue experiments. USP22 is not required for iPSC derivation or maintenance. Mechanistically,USP22 loss during reprogramming downregulates fibroblast-specific genes while activating pluripotency-associated genes,including DNMT3L,LIN28A,SOX2,and GDF3. Additionally,USP22 loss enhances reprogramming efficiency under naïve stem cell conditions. These findings reveal an unrecognized role for USP22 in maintaining somatic cell identity and repressing pluripotency genes,highlighting its potential as a target to improve reprogramming efficiency. Ubiquitin-specific peptidase 22 (USP22) is identified as a key chromatin-based barrier to human iPSC derivation through a chromatin-focused CRISPR-Cas9 screen. View Publication

BackgroundThe epoxyeicosatrienoic acids (EETs) are derivatives of the arachidonic acid metabolism with anti-inflammatory activities. However,their efficacy is limited due to the rapid hydrolysis by soluble epoxide hydrolase (sEH). Inhibition of sEH has been shown to stabilize the EETs and reduce neuroinflammation in A? mouse models of Alzheimer’s disease (AD). However,the role of the sEH-EET signaling pathway in other CNS cell types and neurodegenerative conditions are less understood.MethodsHere we investigated the mechanisms and functional role of the sEH-EET axis in tauopathy by treating PS19 mice with a small molecule sEH inhibitor TPPU and by crossing the PS19 mice with Ephx2 (gene encoding sEH) knockout mice. This was followed by single-nucleus RNA-sequencing (snRNA-seq),biochemical and immunohistochemical analysis,and behavioral assessments. Additionally,we examined the effects of the sEH-EET pathway in primary microglia cultures and human induced pluripotent stem cell (iPSC)-derived neurons exhibiting seeding-induced Tau inclusions.ResultssEH inhibition improved cognitive function,rescued neuronal cell loss,and reduced Tau pathology and microglial reactivity. snRNA-seq revealed that TPPU treatment upregulated genes involved in actin cytoskeleton and excitatory synaptic pathways. Treatment of human iPSC-derived neurons with TPPU enhanced synaptic density without affecting Tau accumulation,suggesting a cell-autonomous neuroprotective effect of sEH blockade. Furthermore,sEH inhibition reversed disease-associated and interferon-responsive microglial states in PS19 mice,while EET supplementation promoted Tau phagocytosis and clearance in primary microglia cultures.ConclusionThese findings demonstrate that sEH blockade or EET augmentation confers therapeutic benefit in neurodegenerative tauopathies by simultaneously targeting neuronal and microglial pathways.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13024-025-00844-x. View Publication

BackgroundThe simultaneous differentiation of human pluripotent stem cells (hPSCs) into both endodermal and mesodermal lineages is crucial for developing complex,vascularized tissues,yet poses significant challenges. This study explores a method for co-differentiation of mesoderm and endoderm,and their subsequent differentiation into pancreatic progenitors (PP) with endothelial cells (EC).MethodsTwo hPSC lines were utilized. By manipulating WNT signaling,we optimized co-differentiation protocols of mesoderm and endoderm through adjusting the concentrations of CHIR99021 and mTeSR1. Subsequently,mesoderm and endoderm were differentiated into vascularized pancreatic progenitors (vPP) by adding VEGFA. The differentiation characteristics and potential of vPPs were analyzed via transcriptome sequencing and functional assays.ResultsA low-dose CHIR99021 in combination with mTeSR1 yielded approximately 30% mesodermal and 70% endodermal cells. Introduction of VEGFA significantly enhanced EC differentiation without compromising PP formation,increasing the EC proportion to 13.9%. Transcriptomic analyses confirmed the effectiveness of our protocol,showing up-regulation of mesodermal and endothelial markers,alongside enhanced metabolic pathways. Functional assays demonstrated that vPPs could efficiently differentiate into insulin-producing ?-cells,as evidenced by increased expression of ?-cell markers and insulin secretion.ConclusionOur findings provide a robust method for generating vPPs,which holds significant promise for regenerative medicine applications,particularly in diabetes treatment.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13287-024-04120-5. View Publication

Human-induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (iMSCs) represent a promising and renewable cell source for therapeutic applications. A systematic evaluation of the immunological properties and engraftment potential of iMSCs generated from urine-derived iPSCs is lacking,which has impeded their broader application. In this study,we differentiated urine-derived iPSCs into iMSCs and assessed their fundamental MSC characteristics,immunogenicity,immunomodulatory capacity and in vivo engraftment. Compared to umbilical cord-derived MSCs (UCMSCs),iMSCs demonstrated an enhanced proliferative capacity,a higher level of regenerative gene expression,and lower immunogenicity,strengthening resistance to apoptosis induced by allogeneic peripheral blood mononuclear cells (PBMCs) and the NK-92 cell line. In addition,iMSCs exhibited a diminished ability to inhibit T cell proliferation and activation compared with UCMSCs. Transcriptomic analyses further revealed the decreased expression of immune regulatory factors in iMSCs. After transfusion into mouse models,iMSCs engrafted in the lungs,liver,and spleen and exhibited the ability to migrate to tumor tissues. Our results indicated that iMSCs generated from urine-derived iPSCs have a significant replicative capacity,low immunogenicity and unique immunomodulatory properties,and hence offer obvious advantages in immune privilege and allogenic therapeutic application prospects. View Publication

Amyotrophic lateral sclerosis (ALS) involves motor neuron death due to mislocalized TDP-43. Pathologic TDP-43 associates with stress granules (SGs),and lowering the SG-associated protein ataxin-2 (ATXN2) using Atxn2-targeting antisense oligonucleotides prolongs survival in TAR4/4 sporadic ALS mice but failed in clinical trials likely due to poor target engagement. Here we show that an AAV with potent motor neuron transduction delivering Atxn2-targeting miRNAs reduces Atxn2 throughout the central nervous system at doses 40x lower than published work. In TAR4/4 mice,miAtxn2 increased survival (50%) and strength,and reduced motor neuron death,inflammation,and phosphorylated TDP-43. TAR4/4 transcriptomic dysregulation recapitulated ALS gene signatures that were rescued by miAtxn2,identifying potential therapeutic mechanisms and biomarkers. In slow progressing hemizygous mice,miAtxn2 slowed disease progression,and in ALS patient-derived lower motor neurons,our AAV vector transduced >95% of cells and potently reduced ATXN2 at MOI 4 logs lower than previously reported. These data support AAV-RNAi targeting ATXN2 as a translatable therapy for sporadic ALS. Amado et al. develop a gene therapy for sporadic ALS using motor neuron-targeting AAVs to deliver RNAi targeting ataxin-2. In a mouse model,survival,strength,and disease-related pathology are improved; and human motor neurons are strongly transduced. View Publication