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Background: Takotsubo cardiomyopathy (TTC) is marked by an acute,transient,and reversible left ventricular systolic dysfunction triggered by stress,with endothelial dysfunction being one of its pathophysiological mechanisms. However,the precise molecular mechanism underlying the interaction between endothelial cells and cardiomyocytes during TTC remains unclear. This study reveals that exosomal miRNAs derived from endothelial cells exposed to catecholamine contribute to ion channel dysfunction in the setting of TTC. Methods: Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) were treated with epinephrine (Epi) or exosomes (Exo) from Epi-treated human cardiac microvascular endothelial cells (HCMECs) or Exo derived from HCMECs transfected with miR-126-3p. The immunofluorescence staining,flow cytometry,qPCR,single-cell contraction,intracellular calcium transients,patch-clamp,dual luciferase reporter assay and western blot were performed for the study. Results: Modeling TTC with high doses of epinephrine (Epi) treatment in hiPSC-CMs shows suppression of depolarization velocity (Vmax),prolongation of action potential duration (APD),and induction of arrhythmic events. Exo derived from HCMECs treated with Epi (Epi-exo) mimicked or enhanced the effects of Epi. Epi exposure led to elevated levels of miR-126-3p in both HCMECs and their exosomes. Exo enriched with miR-126-3p demonstrated similar effects as Epi-exo,establishing the crucial role of miR-126-3p in the mechanism of Epi-exo. Dual luciferase reporter assay coupled with gene mutation techniques identified that miR-126-3p was found to target the regulator of G-protein signaling 3 (RGS3) gene. Western blot and qPCR analyses confirmed that miR-126-3p-mimic reduced RGS3 expression in both HCMECs and hiPSC-CMs,indicating miR-126-3p inhibits RGS3 signaling. Additionally,miR-126-3p levels were significantly higher in the serum of TTC patients compared to healthy controls and patients who had recovered from TTC. Conclusions: Our study is the first to reveal that exosomal miR-126-3p,originating from endothelial cells,contributes to ion channel dysfunction by regulating RGS3 signaling in cardiomyocytes. These findings provide new perspectives on the pathogenesis of TTC and suggest potential therapeutic targets for treatment. View Publication

Mutations in the microtubule binding motor protein,kinesin family member 5A (KIF5A),cause the fatal motor neuron disease,Amyotrophic Lateral Sclerosis. While KIF5 family members transport a variety of cargos along axons,it is still unclear which cargos are affected by KIF5A mutations. We generated KIF5A null mutant human motor neurons to investigate the impact of KIF5A loss on the transport of various cargoes and its effect on motor neuron function at two different timepoints in vitro. The absence of KIF5A resulted in reduced neurite complexity in young motor neurons (DIV14) and significant defects in axonal regeneration capacity at all developmental stages. KIF5A loss did not affect neurofilament transport but resulted in decreased mitochondria motility and anterograde speed at DIV42. More prominently,KIF5A depletion strongly reduced anterograde transport of SFPQ-associated RNA granules in DIV42 motor neuron axons. We conclude that KIF5A most prominently functions in human motor neurons to promote axonal regrowth after injury as well as to anterogradely transport mitochondria and,to a larger extent,SFPQ-associated RNA granules in a time-dependent manner. View Publication

Oropouche fever is a re-emerging global viral threat caused by infection with Oropouche orthobunyavirus (OROV). While disease is generally self-limiting,historical and recent reports of neurologic involvement highlight the importance of understanding the neuropathogenesis of OROV. In this study,we characterize viral replication kinetics in neurons and microglia derived from immortalized,primary,and induced pluripotent stem cell-derived cells,which are all permissive to infection. We demonstrate that ex vivo rat brain slice cultures can be infected by OROV and produce antiviral cytokines and chemokines,including IL-6,TNF-? and IFN-?,which introduces an additional model to study viral kinetics in the central nervous system. These findings provide additional insight into OROV neuropathogenesis and in vitro modeling strategies for a newly re-emerging arbovirus. View Publication

BackgroundPaired box 1 (PAX1) is a transcription factor and essential for the development of pharyngeal pouches-derived tissues,including thymus. PAX1 mutations are identified in Severe Combined Immunodeficiency (SCID) patients with Otofaciocervical Syndrome Type 2 (OTFCS2). However,despite the critical roles of PAX1 in embryonic development and diseases,detailed insights into its molecular mode of action are critically missing.MethodsThe repressing roles of PAX1 and SCID associated mutants on Wnt signaling pathway were investigated by luciferase reporter assays,qRT-PCR and in situ hybridization in HEK293FT,HCT116 cells and zebrafish embryos,respectively. Co-immunoprecipitation (co-IP) and western blotting assays were carried out to identify the molecular mechanisms underlying PAX1’s role on Wnt signaling pathway. hESC based endoderm differentiation,flow cytometry,high-throughput sequencing data analysis,and qRT-PCR assays were utilized to determine the roles of PAX1 during endoderm differentiation.ResultsHere,we show that PAX1 represses canonical Wnt signaling pathway in vertebrate cells. Mechanically,PAX1 competes with SUMO E3 ligase PIASy to bind to TCF7L2,thus perturbing TCF7L2 SUMOylation level,further reducing its transcriptional activity and protein stability. Moreover,we reveal that PAX1 plays dual roles in hESC-derived definitive and foregut/pharyngeal endoderm cells,which give rise to the thymus epithelium,by inhibiting Wnt signaling. Importantly,our data show PAX1 mutations found in SCID patients significantly compromise the suppressing ability of PAX1 on Wnt signaling.ConclusionsOur study presents a novel molecular mode of action of PAX1 in regulation of canonical Wnt signaling and endoderm differentiation,thus providing insights for the molecular basis of PAX1 associated SCID,offering better understanding of the behavior of PAX1 in embryogenesis.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12964-024-01629-3. View Publication

Microglia are the immune cells in the central nervous system (CNS) and become pro-inflammatory/activated in Alzheimer’s disease (AD). Cell surface glycosylation plays an important role in immune cells; however,the N-glycosylation and glycosphingolipid (GSL) signatures of activated microglia are poorly understood. Here,we study comprehensively combined transcriptomic and glycomic profiles using human induced pluripotent stem cells-derived microglia (hiMG). Distinct changes in N-glycosylation patterns in amyloid-? oligomer (A?O) and LPS-treated hiMG were observed. In A?O-treated cells,the relative abundance of bisecting N-acetylglucosamine (GlcNAc) N-glycans decreased,corresponding with a downregulation of MGAT3. The sialylation of N-glycans increased in response to A?O,accompanied by an upregulation of genes involved in N-glycan sialylation (ST3GAL4 and 6). Unlike A?O-induced hiMG,LPS-induced hiMG exhibited a decreased abundance of complex-type N-glycans,aligned with downregulation of mannosidase genes (MAN1A1,MAN2A2,and MAN1C1) and upregulation of ER degradation related-mannosidases (EDEM1-3). Fucosylation increased in LPS-induced hiMG,aligned with upregulated fucosyltransferase 4 (FUT4) and downregulated alpha-L-fucosidase 1 (FUCA1) gene expression,while sialofucosylation decreased,aligned with upregulated neuraminidase 4 (NEU4). Inhibition of sialylation and fucosylation in A?O- and LPS-induced hiMG alleviated pro-inflammatory responses. However,the GSL profile did not exhibit significant changes in response to A?O or LPS activation,at least in the 24-hour stimulation timeframe. A?O- and LPS- specific glycosylation changes could contribute to impaired microglia function,highlighting glycosylation pathways as potential therapeutic targets for AD.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-96596-1. View Publication

Genetic variants often produce complex phenotypic effects that confound current assays and predictive models. We developed Variant in situ sequencing (VIS-seq),a pooled,image-based method that measures variant effects on molecular and cellular phenotypes in diverse cell types. Applying VIS-seq to ~3,000 LMNA and PTEN variants yielded high-dimensional morphological profiles that captured variant-driven changes in protein abundance,localization,activity and cell architecture. We identified gain-of-function LMNA variants that reshape the nucleus and autism-associated PTEN variants that mislocalize. Morphological profiles predicted variant pathogenicity with near-perfect accuracy and distinguished autism-linked from tumor syndrome-linked PTEN variants. Most variants impacted a multidimensional continuum of phenotypes not recapitulated by any single functional readout. By linking protein variation to cell images at scale,we illuminate how variant effects cascade from molecular to subcellular to cell morphological phenotypes,providing a framework for resolving the complexity of variant function. View Publication

A limited number of accessible and representative models of human trophoblast cells currently exist for the study of placentation. Current stem cell models involve either a transition through a naïve stem cell state or precise dynamic control of multiple growth factors and small-molecule cues. Here,we demonstrated that a simple five-day treatment of human induced pluripotent stem cells with two small molecules,retinoic acid (RA) and Wnt agonist CHIR 99021 (CHIR),resulted in rapid,synergistic upregulation of CDX2. Transcriptomic analysis of RA + CHIR-treated cells showed high similarity to primary trophectoderm cells. Multipotency was verified via further differentiation towards cells with syncytiotrophoblast or extravillous trophoblast features. RA + CHIR-treated cells were also assessed for the established criteria defining a trophoblast cell model,and they possess all the features necessary to be considered valid. Collectively,our data demonstrate a facile,scalable method for generating functional trophoblast-like cells in vitro to better understand the placenta. View Publication

This paper presents a 360°,size-adjustable microelectrode array (MEA) system for the long-term electrophysiological monitoring of cerebral organoids derived from human pluripotent stem cells. The system consists of eight independently positionable multielectrode probes,each carrying eight electrodes arranged vertically. This configuration resulted in 64 recording channels surrounding the organoid. The multielectrode probes were mounted on custom-designed miniature manipulators with three degrees of freedom. This setup enabled positioning and contact with organoids of varying sizes (approximately 1–3.7 mm in diameter). The design allowed circumferential access and facilitated standard incubator-based cultivation without disrupting the recording setup. Fabricated using flexible printed circuit technology,this MEA system offers relatively low production costs. It is also amenable to widespread implementation in laboratory settings. Experimental results demonstrated the successful recording of neuronal activity,including spike detection and signal stability,over 2 weeks of continuous organoid culture. These results suggests that the three-dimensional system provides broad spatial coverage and supports long-term monitoring for basic biomedical research. It also holds potential for future applications such as biohybrid computing. View Publication

THOC6 variants are the genetic basis of autosomal recessive THOC6 Intellectual Disability Syndrome (TIDS). THOC6 is critical for mammalian Transcription Export complex (TREX) tetramer formation,which is composed of four six-subunit THO monomers. The TREX tetramer facilitates mammalian RNA processing,in addition to the nuclear mRNA export functions of the TREX dimer conserved through yeast. Human and mouse TIDS model systems revealed novel THOC6-dependent,species-specific TREX tetramer functions. Germline biallelic Thoc6 loss-of-function (LOF) variants result in mouse embryonic lethality. Biallelic THOC6 LOF variants reduce the binding affinity of ALYREF to THOC5 without affecting the protein expression of TREX members,implicating impaired TREX tetramer formation. Defects in RNA nuclear export functions were not detected in biallelic THOC6 LOF human neural cells. Instead,mis-splicing was detected in human and mouse neural tissue,revealing novel THOC6-mediated TREX coordination of mRNA processing. We demonstrate that THOC6 is required for key signaling pathways known to regulate the transition from proliferative to neurogenic divisions during human corticogenesis. Together,these findings implicate altered RNA processing in the developmental biology of TIDS neuropathology. THOC6 is required for TREX tetramer formation. Analysis of pathogenic THOC6 variants differentiate the conserved mRNA export functions of TREX dimers and RNA processing functions of TREX tetramers underlying THOC6 Intellectual Disability Syndrome. 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

During a heart attack,ischemia causes losses of billions of cells; this is especially concerning given the minimal regenerative capability of cardiomyocytes (CMs). Heart remuscularization utilizing stem cells has improved cardiac outcomes despite little cell engraftment,thereby shifting focus to cell-free therapies. Consequently,we chose induced pluripotent stem cells (iPSCs) given their pluripotent nature,efficacy in previous studies,and easy obtainability from minimally invasive techniques. Nonetheless,using iPSC secretome-based therapies for treating injured CMs in a clinical setting is ill-understood. We hypothesized that the iPSC secretome,regardless of donor health,would improve cardiovascular outcomes in the CM model of ischemia–reperfusion (IR) injury. Episomal-generated iPSCs from healthy and dilated cardiomyopathy (DCM) donors,passaged 6–10 times,underwent 24 h incubation in serum-free media. Protein content of the secretome was analyzed by mass spectroscopy and used to treat AC16 immortalized CMs during 5 h reperfusion following 24 h of hypoxia. IPSC-derived secretome content,independent of donor health status,had elevated expression of proteins involved in cell survival pathways. In IR conditions,iPSC-derived secretome increased cell survival as measured by metabolic activity (p < 0.05),cell viability (p < 0.001),and maladaptive cellular remodelling (p = 0.052). Healthy donor-derived secretome contained increased expression of proteins related to calcium contractility compared to DCM donors. Congruently,only healthy donor-derived secretomes improved CM intracellular calcium concentrations (p < 0.01). Heretofore,secretome studies mainly investigated differences relating to cell type rather than donor health. Our work suggests that healthy donors provide more efficacious iPSC-derived secretome compared to DCM donors in the context of IR injury in human CMs. These findings illustrate that the regenerative potential of the iPSC secretome varies due to donor-specific differences. View Publication

The overproduction of reactive oxygen species (ROS) and mitochondrial dysregulation are regarded as key mechanisms in the progression of cardiac remodelling in cardiometabolic diseases including heart failure. Conventional treatments are often ineffective as they do not specifically target the underlying pathological mechanisms. Mitoquinone mesylate (MitoQ),a mitochondrial-targeted antioxidant has been reported to be protective against vascular dysfunction in hypertension,diabetic kidney disease and alcohol-induced liver damage. However,the cardioprotective potential of MitoQ to limit oxidative stress-induced mitochondrial remodelling in cardiomyocytes has not been fully resolved. We sought to investigate the effect of MitoQ and its mitochondrial-targeting moiety dodecyl-triphenylphosphonium (dTPP) on hydrogen peroxide-induced overproduction of ROS,mitochondrial dysregulation and cell death in H9C2 rat cardiomyoblasts (H9C2-rCM) and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CM). Cardiomyocytes were exposed to acute or chronic treatment (5–60 min or 48 h) of vehicle control (0.0001 % Ultrapure Milli-Q water),hydrogen peroxide (100 ?M) ± MitoQ (1 ?M) or dTPP (1 ?M) control. Hydrogen peroxide-induced overproduction of ROS,extracellular superoxide,mitochondrial ROS,mitochondrial hyperpolarisation and cell death were significantly blunted by MitoQ,but not dTPP,suggesting that the coenzyme Q10 moiety of MitoQ is protective under these conditions. Interestingly,both MitoQ and dTPP exhibited a pro-mitochondrial fusion effect by preserving mitochondrial network and reducing mitochondrial fragmentation in oxidative stress conditions. Overall,our findings confirm the cytoprotective potential of MitoQ to limit oxidative stress-induced adverse mitochondrial remodelling and dysregulation that is clinically observed in cardiometabolic-induced cardiac dysfunction in the failing heart. Graphical abstractBioRender Scientific Image and Illustration Software were used to generate the graphical abstract.Unlabelled Image Highlights•Oxidative stress is a key driver of mitochondrial dysregulation and cell death in cardiomyocytes.•MitoQ exhibits cytoprotection against elevated ROS production in human cardiomyocytes.•Mitochondrial structure and regulation were preserved in human cardiomyocytes with MitoQ treatment. View Publication