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Recent successes in deriving human-induced pluripotent stem cells (hiPSCs) allow for the possibility of studying human neurons derived from patients with neurological diseases. Concomitant inhibition of the BMP and TGF-β1 branches of the TGF-β signaling pathways by the endogenous antagonist,Noggin,and the small molecule SB431542,respectively,induces efficient neuralization of hiPSCs,a method known as dual-SMAD inhibition. The use of small molecule inhibitors instead of their endogenous counterparts has several advantages including lower cost,consistent activity,and the maintenance of xeno-free culture conditions. We tested the efficacy of DMH1,a highly selective small molecule BMP-inhibitor for its potential to replace Noggin in the neuralization of hiPSCs. We compare Noggin and DMH1-induced neuralization of hiPSCs by measuring protein and mRNA levels of pluripotency and neural precursor markers over a period of seven days. The regulation of five of the six markers assessed was indistinguishable in the presence of concentrations of Noggin or DMH1 that have been shown to effectively inhibit BMP signaling in other systems. We observed that by varying the DMH1 or Noggin concentration,we could selectively modulate the number of SOX1 expressing cells,whereas PAX6,another neural precursor marker,remained the same. The level and timing of SOX1 expression have been shown to affect neural induction as well as neural lineage. Our observations,therefore,suggest that BMP-inhibitor concentrations need to be carefully monitored to ensure appropriate expression levels of all transcription factors necessary for the induction of a particular neuronal lineage. We further demonstrate that DMH1-induced neural progenitors can be differentiated into β3-tubulin expressing neurons,a subset of which also express tyrosine hydroxylase. Thus,the combined use of DMH1,a highly specific BMP-pathway inhibitor,and SB431542,a TGF-β1-pathway specific inhibitor,provides us with the tools to independently regulate these two pathways through the exclusive use of small molecule inhibitors. View Publication

Control of cellular (de)differentiation in a temporal,cell-specific,and exchangeable manner is of paramount importance in the field of reprogramming. Here,we have generated and characterized a mouse strain that allows iPSC generation through the Cre/loxP conditional and doxycycline/rtTA-controlled inducible expression of the OSKM reprogramming factors entirely from within the ROSA26 locus. After reprogramming,these factors can be replaced by genes of interest-for example,to enhance lineage-directed differentiation-with the use of a trap-coupled RMCE reaction. We show that,similar to ESCs,Dox-controlled expression of the cardiac transcriptional regulator Mesp1 together with Wnt inhibition enhances the generation of functional cardiomyocytes upon in vitro differentiation of such RMCE-retargeted iPSCs. This ROSA26-iPSC mouse model is therefore an excellent tool for studying both cellular reprogramming and lineage-directed differentiation factors from the same locus and will greatly facilitate the identification and ease of functional characterization of the genetic/epigenetic determinants involved in these complex processes. View Publication

The main motor symptoms of Parkinson's disease are due to the loss of dopaminergic (DA) neurons in the ventral midbrain (VM). For the future treatment of Parkinson's disease with cell transplantation it is important to develop efficient differentiation methods for production of human iPSCs and hESCs-derived midbrain-type DA neurons. Here we describe an efficient differentiation and sorting strategy for DA neurons from both human ES/iPS cells and non-human primate iPSCs. The use of non-human primate iPSCs for neuronal differentiation and autologous transplantation is important for preclinical evaluation of safety and efficacy of stem cell-derived DA neurons. The aim of this study was to improve the safety of human- and non-human primate iPSC (PiPSC)-derived DA neurons. According to our results,NCAM(+) /CD29(low) sorting enriched VM DA neurons from pluripotent stem cell-derived neural cell populations. NCAM(+) /CD29(low) DA neurons were positive for FOXA2/TH and EN1/TH and this cell population had increased expression levels of FOXA2,LMX1A,TH,GIRK2,PITX3,EN1,NURR1 mRNA compared to unsorted neural cell populations. PiPSC-derived NCAM(+) /CD29(low) DA neurons were able to restore motor function of 6-hydroxydopamine (6-OHDA) lesioned rats 16 weeks after transplantation. The transplanted sorted cells also integrated in the rodent brain tissue,with robust TH+/hNCAM+ neuritic innervation of the host striatum. One year after autologous transplantation,the primate iPSC-derived neural cells survived in the striatum of one primate without any immunosuppression. These neural cell grafts contained FOXA2/TH-positive neurons in the graft site. This is an important proof of concept for the feasibility and safety of iPSC-derived cell transplantation therapies in the future. View Publication

Human microglia are central regulators and actors in brain infections and neuro-inflammatory pathologies. However,access to such cells is limited,and studies systematically mapping the spectrum of their inflammatory states are scarce. Here,we generated microglia-like cells (MGLCs) from human induced pluripotent stem cells and characterized them as a robust,accessible model system for studying inflammatory activation. We validated lineage identity through transcriptome profiling,revealing selective upregulation of microglial signature genes and enrichment of microglia/macrophage-related gene sets. MGLCs displayed distinct morphologies and produced stimulus- and time-dependent cytokine secretion profiles upon exposure to diverse inflammatory stimuli,including pro-inflammatory cytokines (TNFα,interferon-γ) and agonists of the Toll-like receptors TLR2 (FSL-1),TLR3 (Poly(I:C)),TLR4 (lipopolysaccharide,LPS),and TLR7 (imiquimod). Transcriptome profiling and bioinformatics analysis revealed distinct activation signatures. Functional assays demonstrated stimulus-specific engagement of NFκB and JAK-STAT signaling pathways. The shared NFκB nuclear translocation response of TLR ligands and TNFα was reflected in overlapping transcriptome profiles: they shared modules (e.g.,oxidative stress response and TNFα-related signaling) identified by weighted gene co-expression network analysis. Finally,the potential consequences of microglia activation for neighboring cells were studied on the example of microglia-astrocyte crosstalk. The capacity of MGLC supernatants to stimulate astrocytes was measured by quantifying astrocytic NFκB translocation. MGLCs stimulated with FSL-1,LPS,or Poly(I:C) indirectly activated astrocytes via a strictly TNFα-dependent mechanism,highlighting the role of soluble mediators in the signal propagation. Altogether,this platform enables a dissection of microglia activation states and multi-parametric characterization of subsequent neuroinflammation. View Publication

Hypertrophic cardiomyopathy (HCM) is a common and deadly cardiac disease characterized by enlarged myocytes,increased myocardial wall thickening,and fibrosis. A majority of HCM cases are associated with mutations in the β-myosin heavy chain (MYH7) converter domain locus,which leads to varied pathophysiological and clinical manifestations. Using base-editing technology,we generated mutant human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) harboring HCM-causing myosin converter domain mutations (MYH7 c.2167C>T [R723C]; MYH6 c.2173C>T [R725C]) to define HCM pathogenesis in vitro. In this study,we integrated transcriptomic analysis with phenotypic and molecular analyses to dissect the HCM disease mechanisms using MYH6/7 myosin mutants. Our KEGG analysis of bulk RNA-sequencing data revealed significant upregulation of transcripts associated with HCM in the mutant hiPSC-CMs. Further,in-depth transcriptomic analysis using Gene-Ontology (GO-term) analysis for biological process showed upregulation of several transcripts associated with heart development and disease. Notably,our analysis showed robust upregulation of cytoskeletal transcripts,including actin-cytoskeleton networks,sarcomere components,and other structural proteins in the mutant CMs. Furthermore,cellular and nuclear morphological analysis showed that the MYH6/7 mutation induced cellular hypertrophy and increased aspect ratio compared to the isogenic control. Immunostaining experiments showed marked sarcomere disorganization with lower sarcomeric order and higher dispersion in the mutant hiPSC-CMs,highlighting the remodeling of the myofibril arrangement. Notably,the MYH6/7 mutant showed reduced cortical F-actin expression and increased central F-actin expression compared to the isogenic control,confirming the cytoskeletal remodeling and sarcomeric organization during HCM pathogenesis. These pathological changes accumulated progressively over time,underscoring the chronic and evolving nature of HCM driven by the MYH6/7 mutations. Together,our findings provide critical insights into the cellular and molecular underpinnings of MYH6/7-mutation-associated disease. These findings offer valuable insights into HCM pathogenesis,aiding in future therapies. View Publication

Background and PurposeEsophageal cancer-related gene-4 (ECRG4) participate in inflammation process and can interact with the innate immunity complex TLR4-MD2-CD14 on human granulocytes. In addition,ECRG4 participate in modulation of ion channel function and electrical activity of cardiomyocytes. However,the exact mechanism is unknown. This study aimed to test our hypothesis that ECRG4 contributes to inflammation-induced ion channel dysfunctions in cardiomyocytes.MethodsHuman-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) generated from three donors were treated with lipopolysaccharide (LPS) to establish an endotoxin-induced inflammatory model. Immunostaining,real-time PCR,and patch-clamp techniques were used for the study.ResultsECRG4 was detected in hiPSC-CMs at different differentiation time. LPS treatment increased ECRG4 expression in hiPSC-CMs. Knockdown of ECRG4 decreased the expression level of Toll-Like-Receptor 4 (TLR4,a LPS receptor) and its associated genes and inflammatory cytokines. Furthermore,ECRG4 knockdown shortened the action potential duration (APD) and intercepted LPS-induced APD prolongation by enhancing ISK (small conductance calcium-activated K channel current) and attenuating INCX (Na/Ca exchanger current). Overexpression of ECRG4 mimicked LPS effects on ISK and INCX,which could be prevented by NF?B signaling blockers.ConclusionThis study demonstrated that LPS effects on cardiac ion channel function were mediated by the upregulation of ECRG4,which affects NF?B signaling. Our findings support the roles of ECRG4 in inflammatory responses and the ion channel dysfunctions induced by LPS challenge. View Publication

AbstractA basic assumption underlying induced pluripotent stem cell (iPSC) models of neurodegeneration is that disease-relevant pathologies present in brain tissue are also represented in donor-matched cells differentiated from iPSCs. However,few studies have tested this hypothesis in matched iPSCs and neuropathologically characterized donated brain tissues. To address this,we assessed iPSC-neuron production of ?-amyloid (A?) A?40,A?42,and A?43 in 24 iPSC lines matched to donor brains with primary neuropathologic diagnoses of sporadic AD (sAD),familial AD (fAD),control,and other neurodegenerative disorders. Our results demonstrate a positive correlation between A?43 production by fAD iPSC-neurons and A?43 accumulation in matched brain tissues but do not reveal a substantial correlation in soluble A? species between control or sAD iPSC-neurons and matched brains. However,we found that the ApoE4 genotype is associated with increased A? production by AD iPSC-neurons. Pathologic tau phosphorylation was found to be increased in AD and fAD iPSC-neurons compared to controls and positively correlated with the relative abundance of longer-length A? species produced by these cells. Taken together,our results demonstrate that sAD-predisposing genetic factors influence iPSC-neuron phenotypes and that these cells are capturing disease-relevant and patient-specific components of the amyloid cascade. View Publication

SummaryCytoplasmic mislocalization and aggregation of the RNA-binding protein TDP-43 is a pathological hallmark of the motor neuron (MN) disease amyotrophic lateral sclerosis (ALS). Furthermore,while mutations in TARDBP (encoding TDP-43) have been associated with ALS,the pathogenic consequences of these mutations remain poorly understood. Using CRISPR-Cas9,we engineered two homozygous knock-in induced pluripotent stem cell lines carrying mutations in TARDBP encoding TDP-43A382T and TDP-43G348C,two common yet understudied ALS TDP-43 variants. Motor neurons (MNs) differentiated from knock-in iPSCs had normal viability and displayed no significant changes in TDP-43 subcellular localization,phosphorylation,solubility,or aggregation compared with isogenic control MNs. However,our results highlight synaptic impairments in both TDP-43A382T and TDP-43G348C MN cultures,as reflected in synapse abnormalities and alterations in spontaneous neuronal activity. Collectively,our findings suggest that MN dysfunction may precede the occurrence of TDP-43 pathology and neurodegeneration in ALS and further implicate synaptic and excitability defects in the pathobiology of this disease. Graphical abstract Highlights•Mutant MNs maintain viability but are more vulnerable to cellular stress•Mutant MNs do not show TDP-43 pathology•TDP-43 variants lead to a progressive decline in spontaneous neuronal activity•Functional impairments are accompanied by abnormal synaptic marker expression Molecular neuroscience; Cellular neuroscience View Publication

SUMMARY Resident cardiac macrophages are critical mediators of cardiac function. Despite their known importance to cardiac electrophysiology and tissue maintenance,there are currently no stem-cell-derived models of human engineered cardiac tissues (hECTs) that include resident macrophages. In this study,we made an induced pluripotent stem cell (iPSC)-derived hECT model with a resident population of macrophages (iM0) to better recapitulate the native myocardium and characterized their impact on tissue function. Macrophage retention within the hECTs was confirmed via immunofluorescence after 28 days of cultivation. The inclusion of iM0s significantly impacted hECT function,increasing contractile force production. A potential mechanism underlying these changes was revealed by the interrogation of calcium signaling,which demonstrated the modulation of ?-adrenergic signaling in +iM0 hECTs. Collectively,these findings demonstrate that macrophages significantly enhance cardiac function in iPSC-derived hECT models,emphasizing the need to further explore their contributions not only in healthy hECT models but also in the contexts of disease and injury. In brief Lock and Graney et al. develop a human engineered cardiac tissue with an incorporated iPSC-derived macrophage population to better mimic the complex cell landscape of the native myocardium. Macrophage inclusion leads to increased contractile function of the tissue,which is attributed to macrophage stimulation of the cardiomyocyte ?-adrenergic signaling pathway. Graphical Abstract 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

Interactions between adipose tissue,liver and immune system are at the center of metabolic dysfunction-associated steatotic liver disease and type 2 diabetes. To address the need for an accurate in vitro model,we establish an interconnected microphysiological system (MPS) containing white adipocytes,hepatocytes and proinflammatory macrophages derived from isogenic human induced pluripotent stem cells. Using this MPS,we find that increasing the adipocyte-to-hepatocyte ratio moderately affects hepatocyte function,whereas macrophage-induced adipocyte inflammation causes lipid accumulation in hepatocytes and MPS-wide insulin resistance,corresponding to initiation of metabolic dysfunction-associated steatotic liver disease. We also use our MPS to identify and characterize pharmacological intervention strategies for hepatic steatosis and systemic insulin resistance and find that the glucagon-like peptide-1 receptor agonist semaglutide improves hepatocyte function by acting specifically on adipocytes. These results establish our MPS modeling the adipose tissue-liver axis as an alternative to animal models for mechanistic studies or drug discovery in metabolic diseases. In vitro modelling of the adipose tissue-liver axis can advance understanding and therapy of metabolic disease,including by distinguishing effects of obesity and inflammation. Here,authors develop such a system based on isogenic human iPSCs and interconnected microphysiological devices. View Publication

PIEZO1 is critical to numerous physiological processes,transducing diverse mechanical stimuli into electrical and chemical signals. Recent studies underscore the importance of visualizing endogenous PIEZO1 activity and localization to understand its functional roles. To enable physiologically and clinically relevant studies on human PIEZO1,we genetically engineered human induced pluripotent stem cells (hiPSCs) to express a HaloTag fused to endogenous PIEZO1. Combined with advanced imaging,our chemogenetic platform allows precise visualization of PIEZO1 localization dynamics in various cell types. Furthermore,the PIEZO1-HaloTag hiPSC technology facilitates the non-invasive monitoring of channel activity across diverse cell types using Ca2+-sensitive HaloTag ligands,achieving temporal resolution approaching that of patch clamp electrophysiology. Finally,we use lightsheet microscopy on hiPSC-derived neural organoids to achieve molecular scale imaging of PIEZO1 in three-dimensional tissue. Our advances establish a platform for studying PIEZO1 mechanotransduction in human systems,with potential for elucidating disease mechanisms and targeted drug screening. PIEZO1 is critical in numerous physiological processes,but monitoring its activity and localization in cells can be challenging. Here,the authors present a chemogenetic platform to visualize endogenous human PIEZO1 localization and activity in native cellular conditions,expanding the knowledge on mechanotransduction across single cells and tissue organoids. View Publication