技术资料

Current culture systems available for studying hepatitis D virus (HDV) are suboptimal. In this study,we demonstrate that hepatocyte-like cells (HLCs) derived from human pluripotent stem cells (hPSCs) are fully permissive to HDV infection across various tested genotypes. When co-infected with the helper hepatitis B virus (HBV) or transduced to express the HBV envelope protein HBsAg,HLCs effectively release infectious progeny virions. We also show that HBsAg-expressing HLCs support the extracellular spread of HDV,thus providing a valuable platform for testing available anti-HDV regimens. By challenging the cells along the differentiation with HDV infection,we have identified CD63 as a potential HDV co-entry factor that was rate-limiting for HDV infection in immature hepatocytes. Given their renewable source and the potential to derive hPSCs from individual patients,we propose HLCs as a promising model for investigating HDV biology. Our findings offer new insights into HDV infection and expand the repertoire of research tools available for the development of therapeutic interventions. View Publication

Developmental and epileptic encephalopathies (DEEs) feature altered brain development,developmental delay and seizures,with seizures exacerbating developmental delay. Here we identify a cohort with biallelic variants in DENND5A,encoding a membrane trafficking protein,and develop animal models with phenotypes like the human syndrome. We demonstrate that DENND5A interacts with Pals1/MUPP1,components of the Crumbs apical polarity complex required for symmetrical division of neural progenitor cells. Human induced pluripotent stem cells lacking DENND5A fail to undergo symmetric cell division with an inherent propensity to differentiate into neurons. These phenotypes result from misalignment of the mitotic spindle in apical neural progenitors. Cells lacking DENND5A orient away from the proliferative apical domain surrounding the ventricles,biasing daughter cells towards a more fate-committed state,ultimately shortening the period of neurogenesis. This study provides a mechanism for DENND5A-related DEE that may be generalizable to other developmental conditions and provides variant-specific clinical information for physicians and families. Developmental and epileptic encephalopathies are devastating neurological disorders. Here,the authors establish a cohort of patients with variants in the gene DENND5A and use human stem cells to discover a disease mechanism involving altered cell division. View Publication

Poisoning with the organophosphorus nerve agent VX can be life-threatening due to limitations of the standard therapy with atropine and oximes. To date,the underlying pathomechanism of VX affecting the neuromuscular junction has not been fully elucidated structurally. Results of recent studies investigating the effects of VX were obtained from cells of animal origin or immortalized cell lines limiting their translation to humans. To overcome this limitation,motor neurons (MN) of this study were differentiated from in-house feeder- and integration-free-derived human-induced pluripotent stem cells (hiPSC) by application of standardized and antibiotic-free differentiation media with the aim to mimic human embryogenesis as closely as possible. For testing VX sensitivity,MN were initially exposed once to 400 µM,600 µM,800 µM,or 1000 µM VX and cultured for 5 days followed by analysis of changes in viability and neurite outgrowth as well as at the gene and protein level using µLC-ESI MS/HR MS,XTT,IncuCyte,qRT-PCR,and Western Blot. For the first time,VX was shown to trigger neuronal cell death and decline in neurite outgrowth in hiPSC-derived MN in a time- and concentration-dependent manner involving the activation of the intrinsic as well as the extrinsic pathway of apoptosis. Consistent with this,MN morphology and neurite network were altered time and concentration-dependently. Thus,MN represent a valuable tool for further investigation of the pathomechanism after VX exposure. These findings might set the course for the development of a promising human neuromuscular test model and patient-specific therapies in the future. View Publication

Recent developments in auxin-inducible degron (AID) technology have increased its popularity for chemogenetic control of proteolysis. However,generation of human AID cell lines is challenging,especially in human embryonic stem cells (hESCs). Here,we develop HiHo-AID2,a streamlined procedure for rapid,one-step generation of human cancer and hESC lines with high homozygous degron-tagging efficiency based on an optimized AID2 system and homology-directed repair enhancers. We demonstrate its application for rapid and inducible functional inactivation of twelve endogenous target proteins in five cell lines,including targets with diverse expression levels and functions in hESCs and cells differentiated from hESCs.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13059-024-03187-w. View Publication

AbstractNeurofilament light (NfL) concentration in CSF and blood serves as an important biomarker in neurology drug development. Changes in NfL are generally assumed to reflect changes in neuronal damage,while little is known about the clearance of NfL from biofluids. In a study of asymptomatic individuals at risk for prion disease,both blood and CSF NfL spiked in one participant following a 6-week course of minocycline,absent any other biomarker changes and without subsequent onset of symptoms. We subsequently observed high NfL after minocycline treatment in discarded clinical plasma samples from inpatients,in mouse plasma and in conditioned media from neuron–microglia co-cultures. The specificity and kinetics of NfL response lead us to hypothesize that minocycline does not cause or exacerbate neuronal damage,but instead affects NfL by inhibiting its clearance,posing a potential confounder for the interpretation of this important biomarker. Gentile et al. report that treatment with the drug minocycline may cause neurofilament light concentration to rise in CSF and blood. This effect appears mediated by changes in clearance of the protein,rather than release from tissue,confounding this biomarker normally held to report on neuronal health. View Publication

A growing body of clinical literature has described neurodevelopmental delays in infants with chronic prenatal opioid exposure and withdrawal. Despite this,the mechanism of how opioids impact the developing brain remains unknown. Here,we developed an in vitro model of prenatal morphine exposure and withdrawal using healthy human induced pluripotent stem cell (iPSC)-derived midbrain neural progenitors in monolayer. To optimize our model,we identified that a longer neural induction and regional patterning period increases expression of canonical opioid receptors mu and kappa in midbrain neural progenitors compared to a shorter protocol (OPRM1,two-tailed t-test,p =? 0.004; OPRK1,p =? 0.0003). Next,we showed that the midbrain neural progenitors derived from a longer iPSC neural induction also have scant toll-like receptor 4 (TLR4) expression,a key player in neonatal opioid withdrawal syndrome pathophysiology. During morphine withdrawal,differentiating neural progenitors experience cyclic adenosine monophosphate overshoot compared to cell exposed to vehicle (p =? 0.0496) and morphine exposure conditions (p,=? 0.0136,1-way ANOVA). Finally,we showed that morphine exposure and withdrawal alters proportions of differentiated progenitor cell fates (2-way ANOVA,F =? 16.05,p View Publication

SUMMARYHuman neurogenesis is disproportionately protracted,lasting >10 times longer than in mouse,allowing neural progenitors to undergo more rounds of self-renewing cell divisions and generate larger neuronal populations. In the human spinal cord,expansion of the motor neuron lineage is achieved through a newly evolved progenitor domain called vpMN (ventral motor neuron progenitor) that uniquely extends and expands motor neurogenesis. This behavior of vpMNs is controlled by transcription factor NKX2-2,which in vpMNs is co-expressed with classical motor neuron progenitor (pMN) marker OLIG2. In this study,we sought to determine the molecular basis of NKX2-2-mediated extension and expansion of motor neurogenesis. We found that NKX2-2 represses proneural gene NEUROG2 by two distinct,Notch-independent mechanisms that are respectively apparent in rodent and human spinal progenitors: in rodents (and chick),NKX2-2 represses Olig2 and the motor neuron lineage through its tinman domain,leading to loss of Neurog2 expression. In human vpMNs,however,NKX2-2 represses NEUROG2 but not OLIG2,thereby allowing motor neurogenesis to proceed,albeit in a delayed and protracted manner. Interestingly,we found that ectopic expression of tinman-mutant Nkx2-2 in mouse pMNs phenocopies human vpMNs,repressing Neurog2 but not Olig2,and leading to delayed and protracted motor neurogenesis. Our studies identify a Notch- and tinman-independent mode of Nkx2-2-mediated Neurog2 repression that is observed in human spinal progenitors,but is normally masked in rodents and chicks due to Nkx2-2’s tinman-dependent repression of Olig2. View Publication

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

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

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