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Genomic imprinting controls parental allele-specific gene expression via epigenetic mechanisms. Abnormal imprinting at the GNAS gene causes multiple phenotypes,including pseudohypoparathyroidism type-1B (PHP1B),a disorder of multihormone resistance. Microdeletions affecting the neighboring STX16 gene ablate an imprinting control region (STX16-ICR) of GNAS and lead to PHP1B upon maternal but not paternal inheritance. Mechanisms behind this imprinted inheritance mode remain unknown. Here,we show that the STX16-ICR forms different chromatin conformations with each GNAS parental allele and enhances two GNAS promoters in human embryonic stem cells. When these cells differentiate toward proximal renal tubule cells,STX16-ICR loses its effect,accompanied by a transition to a somatic cell-specific GNAS imprinting status. The activity of STX16-ICR depends on an OCT4 motif,whose disruption impacts transcript levels differentially on each allele. Therefore,a biallelically active embryonic enhancer dictates GNAS imprinting via different chromatin conformations,underlying the allele-specific pathogenicity of STX16-ICR microdeletions. STX16 microdeletions cause pseudohypoparathyroidism type-1B only on the maternal allele. Here,the authors show that the allele-specific pathogenicity reflects differential conformations of a biallelically active enhancer dictating GNAS imprinting. View Publication

Brain tumors are commonly treated with radiotherapy,but the efficacy of the treatment is limited by its toxicity to the normal tissue including post-irradiation contrast enhanced lesions often linked to necrosis. The poorly understood mechanisms behind such brain lesions were studied using cerebral organoids. Here we show that irradiation of such organoids leads to dose-dependent growth retardation and formation of liquid-filled cavities but is not correlated with necrosis. Instead,the radiation-induced changes comprise of an enhancement of cortical hem markers,altered neuroepithelial stem cell differentiation,and an increase of ZO1+/AQP1+/CLDN3+-choroid plexus (CP)-like structures accompanied by an upregulation of IGF2 mRNA,known to be expressed in CP and cerebrospinal fluid. The altered differentiation is attributed to changes in the WNT/BMP signaling pathways. We conclude that aberrant CP formation can be involved in radiation-induced brain lesions providing additional strategies for possible countermeasures. Human cerebral organoids provide insights into mechanisms behind the formation of choroid plexus (CP)-like structures that may contribute to radiation-induced brain image changes. View Publication

Huntington disease (HD) is a neurodegenerative disease caused by the abnormal expansion of a polyglutamine tract resulting from a mutation in the HTT gene. Oxidative stress has been identified as a significant contributing factor to the development of HD and other neurodegenerative diseases,and targeting anti-oxidative stress has emerged as a potential therapeutic approach. CHCHD2 is a mitochondria-related protein involved in regulating cell migration,anti-oxidative stress,and anti-apoptosis. Although CHCHD2 is highly expressed in HD cells,its specific role in the pathogenesis of HD remains uncertain. We postulate that the up-regulation of CHCHD2 in HD models represents a compensatory protective response against mitochondrial dysfunction and oxidative stress associated with HD. To investigate this hypothesis,we employed HD mouse striatal cells and human induced pluripotent stem cells (hiPSCs) as models to examine the effects of CHCHD2 overexpression (CHCHD2-OE) or knockdown (CHCHD2-KD) on the HD phenotype. Our findings demonstrate that CHCHD2 is crucial for maintaining cell survival in both HD mouse striatal cells and hiPSCs-derived neurons. Our study demonstrates that CHCHD2 up-regulation in HD serves as a compensatory protective response against oxidative stress,suggesting a potential anti-oxidative strategy for the treatment of HD. View Publication

The cytoplasmic RIG-I-like receptors (RLRs) recognize viral RNA and initiate innate antiviral immunity. RLR signaling also triggers glycolytic reprogramming through glucose transporters (GLUTs),whose role in antiviral immunity is elusive. Here,we unveil that insulin-responsive GLUT4 inhibits RLR signaling independently of glucose uptake in adipose and muscle tissues. At steady state,GLUT4 is docked at the Golgi matrix by ubiquitin regulatory X domain 9 (UBXN9,TUG). Following RNA virus infection,GLUT4 is released and translocated to the cell surface where it spatially segregates a significant pool of cytosolic RLRs,preventing them from activating IFN-? responses. UBXN9 deletion prompts constitutive GLUT4 trafficking,sequestration of RLRs,and attenuation of antiviral immunity,whereas GLUT4 deletion heightens RLR signaling. Notably,reduced GLUT4 expression is uniquely associated with human inflammatory myopathies characterized by hyperactive interferon responses. Overall,our results demonstrate a noncanonical UBXN9-GLUT4 axis that controls antiviral immunity via plasma membrane tethering of cytosolic RLRs. View Publication

IntroductionNeuroinflammation is a key contributor to the pathogenesis of Alzheimer's disease (AD),and impaired clearance of amyloid-? (A?) by microglia is closely associated with disease progression. Oxytocin (OXT),a hypothalamic neuropeptide,has recently been reported to exert anti-inflammatory effects on microglia; however,its therapeutic potential in the human brain remains unclear.MethodsWe generated human cerebral organoids (hCOs) from induced pluripotent stem cells (iPSCs) to model early AD-like pathology. A? toxicity was induced by applying 3 ?M A?1–42 for 48 h. The protective effects of OXT were evaluated through immunohistochemistry,RT-qPCR,calcium imaging,and multielectrode array (MEA) recordings. The involvement of microglia in A? clearance was assessed by immunostaining and gene expression analysis of TREM2.ResultsA? exposure led to significant deposition of A? in the outer layers of hCOs,accompanied by suppressed neural activity and increased apoptotic signaling. Pretreatment with OXT attenuated A? deposition and caspase-3-mediated apoptosis in a concentration-dependent manner. OXT also restored calcium oscillations and neuronal network activity as measured by MEA. Notably,OXT enhanced the recruitment of microglia to A? deposits and upregulated the expression of TREM2,a key regulator of microglial phagocytosis. Co-expression of oxytocin receptors (OXTR) on Iba1-positive microglia suggests that OXT directly modulates microglial activation and A? clearance.ConclusionsOXT has neuroprotective effects on human cortical organoids by preserving their neuronal activity and promoting microglial-mediated A? clearance. This study provides novel insights into the therapeutic potential of OXT for targeting neuroinflammation and A? pathology in patients with AD. Graphical abstractImage 1 Highlights•Oxytocin reduces A? deposition and apoptosis in human cerebral organoids.•A? impairs neuronal activity,rescued by oxytocin preconditioning.•Oxytocin enhances microglial phagocytosis via OXTR and TREM2 upregulation.•Human iPSC-derived organoids model early A? pathology and oxytocin response. View Publication

BackgroundThe expansion of GGC repeats (typically exceeding 60 repeats) in the 5’ untranslated region (UTR) of the NOTCH2NLC gene (N2C) is linked to N2C-related repeat expansion disorders (NREDs),such as neuronal intranuclear inclusion disease (NIID),frontotemporal dementia (FTD),essential tremor (ET),and Parkinson’s disease (PD). These disorders share common clinical manifestations,including parkinsonism,dementia,seizures,and muscle weakness. Intermediate repeat sizes ranging from 40 to 60 GGC repeats,particularly those with AGC-encoded serine insertions,have been reported to be associated with PD; however,the functional implications of these intermediate repeats with serine insertion remain unexplored.MethodsHere,we utilized cellular models harbouring different sizes of N2C variant 2 (N2C2) GGC repeat expansion and CRISPR-Cas9 engineered transgenic mouse models carrying N2C2 GGC intermediate repeats with and without serine insertion to elucidate the underlying pathophysiology associated with N2C intermediate repeat with serine insertion in NREDs.ResultsOur findings revealed that the N2C2 GGC intermediate repeat with serine insertion (32G13S) led to mitochondrial dysfunction and cell death in vitro. The neurotoxicity was influenced by the length of the repeat and was exacerbated by the presence of the serine insertion. In 12-month-old transgenic mice,32G13S intensified intranuclear aggregation and exhibited early PD-like characteristics,including the formation of ?-synuclein fibers in the midbrain and the loss of tyrosine hydroxylase (TH)-positive neurons in both the cortex and striatum. Additionally,32G13S induced neuronal hyperexcitability and caused locomotor behavioural impairments. Transcriptomic analysis of the mouse cortex indicated dysregulation in calcium signaling and MAPK signaling pathways,both of which are critical for mitochondrial function. Notably,genes associated with myelin sheath components,including MBP and MOG,were dysregulated in the 32G13S mouse. Further investigations using immunostaining and transmission electron microscopy revealed that the N2C intermediate repeat with serine induced mitochondrial dysfunction-related hypermyelination in the cortex.ConclusionsOur in vitro and in vivo investigations provide the first evidence that the N2C-GGC intermediate repeat with serine promotes intranuclear aggregation of N2C,leading to mitochondrial dysfunction-associated hypermyelination and neuronal hyperexcitability. These changes contribute to motor deficits in early PD-like neurodegeneration in NREDs.Supplementary InformationThe online version contains supplementary material available at 10.1186/s13024-024-00780-2. View Publication

Rett syndrome (RTT) is a neurodevelopmental disorder that is caused by mutations in melty-CpG binding protein 2 (MeCP2). MeCP2 is a non-cell type-specific DNA binding protein,and its mutation influences not only neural cells but also non-neural cells in the brain,including vasculature associated with endothelial cells. Vascular integrity is crucial for maintaining brain homeostasis,and its alteration may be linked to the pathology of neurodegenerative disease,but a non-neurogenic effect,especially the relationship between vascular alternation and Rett syndrome pathogenesis,has not been shown. Here,we recapitulate a microvascular network using Rett syndrome patient-derived induced pluripotent stem (iPS) cells that carry MeCP2[R306C] mutation to investigate early developmental vascular impact. To expedite endothelial cell differentiation,doxycycline (DOX)-inducible ETV2 expression vectors were inserted into the AAVS1 locus of Rett syndrome patient-derived iPS cells and its isogenic control by CRISPR/Cas9. With these endothelial cells,we established a disease microvascular network (Rett-dMVNs) and observed higher permeability in the Rett-dMVNs compared to isogenic controls,indicating altered barrier function by MeCP2 mutation. Furthermore,we unveiled that hyperpermeability is involved in the upregulation of miR126–3p in Rett syndrome patient-derived endothelial cells by microRNA profiling and RNAseq,and rescue of miR126–3p level can recover their phenotype. We discover miR126–3p-mediated vascular impairment in Rett syndrome patients and suggest the potential application of these findings for translational medicine. View Publication

PurposeLittle is known about the development of Bruch's membrane (BrM),the structure separating and supporting the retina and choroid,nor whether differentiation of human pluripotent stem cell (hPSC)-derived retinal pigment epithelium (RPE) accurately replicates BrM. This has relevance for tissue engineering strategies,both in the development of accurate in vitro models,and effective RPE transplant strategies. Here,we investigated BrM-associated protein production in human fetal tissue and hPSC-derived RPE.MethodsThe presence of laminin,elastin,fibronectin,and types I/III/IV collagen was examined in human fetal eyes at 6 to 21 post-conception weeks (PCWs) and hPSC-derived RPE cultures at 1 to 6 weeks in culture using immunohistochemistry/immunocytochemistry and quantitative PCR (qPCR).ResultsIn human fetal retina,laminin and fibronectin were present from 6 PCW,type IV collagen from 8 PCW,elastin from 12 PCW,type I collagen by 17 PCW,and type III collagen from 21 PCW. BrM layering was discernible from 12 PCW,becoming distinct by 17 PCW. In hPSC-derived RPE cultures,basement membranes containing laminin and fibronectin were present from week 1,type IV collagen from week 2,and type I collagen from week 4. Type III collagen was present at all timepoints,although not localized as a basement membrane. Elastin was absent at all timepoints.ConclusionsBrM-like membrane synthesis in hPSC-derived RPE largely recapitulates the temporal sequence seen in human development,excluding elastin. These support the utility of hPSC-derived RPE in in vitro systems to model RPE/retina interactions in health and disease,and inform cell therapy approaches,as de novo BrM-like membrane has the potential to support transplanted donor RPE. View Publication

SummaryApolipoprotein E4 (APOE4) is the leading genetic risk factor for Alzheimer’s disease. While most studies examine the role of APOE4 in aging,APOE4 causes persistent changes in brain structure as early as infancy and is associated with altered functional connectivity that extends beyond adolescence. Here,we used human induced pluripotent stem cell-derived cortical and ganglionic eminence organoids (COs and GEOs) to examine APOE4’s influence during the development of cortical excitatory and inhibitory neurons. We show that APOE4 reduces cortical neurons and increases glia by promoting gliogenic transcriptional programs. In contrast,APOE4 increases proliferation and differentiation of GABAergic progenitors resulting in early and persistent increases in GABAergic neurons. Multi-electrode array recordings in assembloids revealed that APOE4 disrupts neural network function resulting in heightened excitability and synchronicity. Together,our data provide new insights on how APOE4 influences cortical neurodevelopmental processes and the establishment of functional networks. Highlights•APOE4 accelerates differentiation and maturation at developmental time points•APOE4 results in a loss of cortical neurons and increase in astrocytes and outer radial glia•APOE4 enhances proliferation,differentiation,and maturation of GABAergic neurons•APOE4 alters GABA-related genes,linked to increased GABA response and synchronicity Meyer-Acosta et al. reveal that Alzheimer’s disease genetic risk factor APOE4 decreases cortical neurons and increases glia in cortical organoids and enhances GABAergic neuron maturation in ganglionic eminence organoids derived from iPSCs. These cellular changes result in heightened excitability and synchronicity in APOE4-fused organoids,providing insight into the cellular processes that may underlie altered brain structure observed in APOE4 infants. View Publication

ETV6::RUNX1,the most common oncogenic fusion in pediatric B cell precursor acute lymphoblastic leukemia (BCP-ALL),induces a clinically silent preleukemic state that can persist in carriers for over a decade and may progress to overt leukemia upon acquisition of secondary lesions. The mechanisms contributing to quiescence of ETV6::RUNX1+ preleukemic cells still remain elusive. In this study,we identify linker histone H1-0 as a critical mediator of the ETV6::RUNX1+ preleukemic state by employing human -induced pluripotent stem cell (hiPSC) models engineered by using CRISPR/Cas9 gene editing. Global gene expression analysis revealed upregulation of H1-0 in ETV6::RUNX1+ hiPSCs that was preserved upon hematopoietic differentiation. Moreover,whole transcriptome data of 1,727 leukemia patient samples showed significantly elevated H1-0 levels in ETV6::RUNX1+ BCP-ALL compared to other leukemia entities. Using dual-luciferase promoter assays,we show that ETV6::RUNX1 induces H1-0 promoter activity. We further demonstrate that depletion of H1-0 specifically inhibits ETV6::RUNX1 signature genes,including RAG1 and EPOR. Single-cell sequencing showed that H1-0 is highly expressed in quiescent hematopoietic cells. Importantly,H1-0 protein levels correspond to susceptibility of BCP-ALL cells towards histone deacetylase inhibitors (HDACis) and combinatorial treatment using the H1-0-inducing HDACi Quisinostat showed promising synergism with established chemotherapeutic drugs. Taken together,our data identify H1-0 as a key regulator of the ETV6::RUNX1+ transcriptome and indicate that the addition of Quisinostat may be beneficial to target non-responsive or relapsing ETV6::RUNX1+ BCP-ALL. View Publication

BackgroundNatural killer (NK) cells are key effector cells of antitumor immunity. However,tumors can acquire resistance programs to escape NK cell-mediated immunosurveillance. Identifying mechanisms that mediate this resistance enables us to define approaches to improve immune-mediate antitumor activity. In previous studies from our group,a genome-wide CRISPR-Cas9 screen identified Charged Multivesicular Body Protein 2A (CHMP2A) as a novel mechanism that mediates tumor intrinsic resistance to NK cell activity.MethodsHere,we use an immunocompetent mouse model to demonstrate that CHMP2A serves as a targetable regulator of not only NK cell-mediated immunity but also other immune cell populations. Using the recently characterized murine 4MOSC model system,a syngeneic,tobacco-signature murine head and neck squamous cell carcinoma model,we deleted mCHMP2A using CRISPR/Cas9-mediated knock-out (KO),following orthotopic transplantation into immunocompetent hosts.ResultsWe found that mCHMP2A KO in 4MOSC1 cells leads to more potent NK-mediated tumor cell killing in vitro in these tumor cells. Moreover,following orthotopic transplantation,KO of mCHMP2A in 4MOSC1 cells,but not the more immune-resistant 4MOSC2 cells enables both T cells and NK cells to better mediate antitumor activity compared with wild type (WT) tumors. However,there was no difference in tumor development between WT and mCHMP2A KO 4MOSC1 or 4MOSC2 tumors when implanted in immunodeficient mice. Mechanistically,we find that mCHMP2A KO 4MOSC1 tumors transplanted into the immunocompetent mice had significantly increased CD4+T cells,CD8+T cells. NK cell,as well as fewer myeloid-derived suppressor cells (MDSC).ConclusionsTogether,these studies demonstrate that CHMP2A is a targetable inhibitor of cellular antitumor immunity. View Publication

In sub-Saharan Africa,multidrug-resistant non-typhoidal Salmonella serovars are a common cause of fatal bloodstream infection. Malnutrition is a predisposing factor,but the underlying mechanisms are unknown. Here we show that vitamin A deficiency,one of the most prevalent micronutrient deficits afflicting African children,increases susceptibility to disseminated non-typhoidal Salmonella disease in mice and impairs terminal neutrophil maturation. Immature neutrophils had reduced expression of Slc11a1,a gene that encodes a metal ion transporter generally thought to restrict pathogen growth in macrophages. Adoptive transfer of SLC11A1-proficient neutrophils,but not SLC11A1-deficient neutrophils,reduced systemic Salmonella burden in Slc11a1−/− mice or mice with vitamin A deficiency. Loss of terminal granulopoiesis regulator CCAAT/enhancer-binding protein ϵ (C/EBPϵ) also decreased neutrophil-mediated control of Salmonella,but not that mediated by peritoneal macrophages. Susceptibility to infection increased in Cebpe−/− Slc11a1+/+ mice compared with wild-type controls,in an Slc11a1-expression-dependent manner. These data suggest that SLC11A1 deficiency impairs Salmonella control in part by blunting neutrophil-mediated defence. Vitamin A deficiency exacerbates invasive non-typhoidal Salmonella infection in mice,revealing a restrictive role for SLC11A1 in neutrophils. View Publication