In this study, we investigated whether intrinsic glial dysfunction contributes to the pathogenesis of schizophrenia (SCZ). Our approach was to establish humanized glial chimeric mice using glial ...progenitor cells (GPCs) produced from induced pluripotent stem cells derived from patients with childhood-onset SCZ. After neonatal implantation into myelin-deficient shiverer mice, SCZ GPCs showed premature migration into the cortex, leading to reduced white matter expansion and hypomyelination relative to controls. The SCZ glial chimeras also showed delayed astrocytic differentiation and abnormal astrocytic morphologies. When established in myelin wild-type hosts, SCZ glial mice showed reduced prepulse inhibition and abnormal behavior, including excessive anxiety, antisocial traits, and disturbed sleep. RNA-seq of cultured SCZ human glial progenitor cells (hGPCs) revealed disrupted glial differentiation-associated and synaptic gene expression, indicating that glial pathology was cell autonomous. Our data therefore suggest a causal role for impaired glial maturation in the development of schizophrenia and provide a humanized model for its in vivo assessment.
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•Human glial chimeric mice were made using iPSCs derived from schizophrenic subjects•SCZ glial chimeras develop abnormal astrocytic morphology and hypomyelination•Differentiation-associated gene expression is impaired in SCZ glial progenitors•SCZ glial chimeric mice have broad behavioral and sleep abnormalities
Goldman and colleagues use mice chimerized with human patient-derived glial progenitor cells to find out whether glia contribute to childhood-onset schizophrenia. The defects in cell differentiation, myelination, and behavior they see strongly suggest that glial cells do, in fact, have a previously unappreciated role in the pathogenesis of this disease.
The causal contribution of glial pathology to Huntington disease (HD) has not been heavily explored. To define the contribution of glia to HD, we established human HD glial chimeras by neonatally ...engrafting immunodeficient mice with mutant huntingtin (mHTT)-expressing human glial progenitor cells (hGPCs), derived from either human embryonic stem cells or mHTT-transduced fetal hGPCs. Here we show that mHTT glia can impart disease phenotype to normal mice, since mice engrafted intrastriatally with mHTT hGPCs exhibit worse motor performance than controls, and striatal neurons in mHTT glial chimeras are hyperexcitable. Conversely, normal glia can ameliorate disease phenotype in transgenic HD mice, as striatal transplantation of normal glia rescues aspects of electrophysiological and behavioural phenotype, restores interstitial potassium homeostasis, slows disease progression and extends survival in R6/2 HD mice. These observations suggest a causal role for glia in HD, and further suggest a cell-based strategy for disease amelioration in this disorder.
Huntington’s disease (HD) is characterized by hypomyelination and neuronal loss. To assess the basis for myelin loss in HD, we generated bipotential glial progenitor cells (GPCs) from human embryonic ...stem cells (hESCs) derived from mutant Huntingtin (mHTT) embryos or normal controls and performed RNA sequencing (RNA-seq) to assess mHTT-dependent changes in gene expression. In human GPCs (hGPCs) derived from 3 mHTT hESC lines, transcription factors associated with glial differentiation and myelin synthesis were sharply downregulated relative to normal hESC GPCs; NKX2.2, OLIG2, SOX10, MYRF, and their downstream targets were all suppressed. Accordingly, when mHTT hGPCs were transplanted into hypomyelinated shiverer mice, the resultant glial chimeras were hypomyelinated; this defect could be rescued by forced expression of SOX10 and MYRF by mHTT hGPCs. The mHTT hGPCs also manifested impaired astrocytic differentiation and developed abnormal fiber architecture. White matter involution in HD is thus a product of the cell-autonomous, mHTT-dependent suppression of glial differentiation.
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•Mutant HTT-expressing hESCs exhibit a relative block in glial lineage progression•Differentiation-associated genes are downregulated in mHTT glial progenitor cells•Human glial chimeras established with mHTT glial progenitors are hypomyelinated•mHTT human glial chimeras manifest disrupted astrocytic differentiation
The authors show that glial progenitor cells derived from human ESCs expressing mutant Huntingtin (mHTT) are delayed and defective in their maturation; their suppressed transcription of differentiation-associated genes leads to both astrocytic dysfunction and myelin deficiency in vivo. Glial pathology may thus contribute to disease phenotype in Huntington’s disease.
Glial pathology is a causal contributor to the striatal neuronal dysfunction of Huntington’s disease (HD). We investigate mutant HTT-associated changes in gene expression by mouse and human striatal ...astrocytes, as well as in mouse microglia, to identify commonalities in glial pathobiology across species and models. Mouse striatal astrocytes are fluorescence-activated cell sorted (FACS) from R6/2 and zQ175 mice, which respectively express exon1-only or full-length mHTT, and human astrocytes are generated either from human embryonic stem cells (hESCs) expressing full-length mHTT or from fetal striatal astrocytes transduced with exon1-only mHTT. Comparison of differential gene expression across these conditions, all with respect to normal HTT controls, reveals cell-type-specific changes in transcription common to both species, yet with differences that distinguish glia expressing truncated mHTT versus full-length mHTT. These data indicate that the differential gene expression of glia expressing truncated mHTT may differ from that of cells expressing full-length mHTT, while identifying a conserved set of dysregulated pathways in HD glia.
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•Glial transcription differs between cells expressing full-length and exon1-only mHTT•Truncated mHTT inhibits glial cholesterol pathway expression; full-length mHTT does not•Astrocytic structural genes are dysregulated by mHTT-expressing glia in all models•Mutant HTT-expressing mouse astrocytes manifest altered fiber distributions in vivo
Benraiss et al. assess astrocytic and microglial gene expression across mouse and human models of Huntington’s disease, to define commonalities that may contribute to HD pathogenesis. They report differences between glia expressing full-length and exon 1-only mHTT and identify a core set of dysregulated pathways that predict glial pathology.
Astrocytic differentiation is developmentally impaired in patients with childhood-onset schizophrenia (SCZ). To determine why, we used genetic gain- and loss-of-function studies to establish the ...contributions of differentially expressed transcriptional regulators to the defective differentiation of glial progenitor cells (GPCs) produced from SCZ patient-derived induced pluripotent cells (iPSCs). Negative regulators of the bone morphogenetic protein (BMP) pathway were upregulated in SCZ GPCs, including BAMBI, FST, and GREM1, whose overexpression retained SCZ GPCs at the progenitor stage. SMAD4 knockdown (KD) suppressed the production of these BMP inhibitors by SCZ GPCs and rescued normal astrocytic differentiation. In addition, the BMP-regulated transcriptional repressor REST was upregulated in SCZ GPCs, and its KD similarly restored normal glial differentiation. REST KD also rescued potassium-transport-associated gene expression and K+ uptake, which were otherwise deficient in SCZ glia. These data suggest that the glial differentiation defect in childhood-onset SCZ, and its attendant disruption in K+ homeostasis, may be rescued by targeting BMP/SMAD4- and REST-dependent transcription.
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•Dysregulated BMP signaling restricts the differentiation of SCZ glial progenitor cells•REST is regulated by BMP/SMAD4 signaling and is overexpressed by SCZ GPCs•SMAD4 knockdown rescues normal astrocytic differentiation by SCZ GPCs•REST knockdown rescues K+ transporter gene expression and K+ uptake by SCZ glia
Astrocytic differentiation is impaired in childhood-onset schizophrenia (SCZ). Liu et al. report that SMAD4-dependent BMP signaling and REST are upregulated in hiPSC-derived SCZ glia and that SMAD4 and REST knockdown rescue both astroglial differentiation and K+ transport. SCZ astrocytic maturation may thus be rescued by targeting SMAD4- and REST-dependent transcription.
Large-scale multiparameter screening has become increasingly feasible and straightforward to perform thanks to developments in technologies such as high-content microscopy and high-throughput flow ...cytometry. The automated toolkits for analyzing similarities and differences between large numbers of tested conditions have not kept pace with these technological developments. Thus, effective analysis of multiparameter screening datasets becomes a bottleneck and a limiting factor in unbiased interpretation of results. Here we introduce compaRe, a toolkit for large-scale multiparameter data analysis, which integrates quality control, data bias correction, and data visualization methods with a mass-aware gridding algorithm-based similarity analysis providing a much faster and more robust analyses than existing methods. Using mass and flow cytometry data from acute myeloid leukemia and myelodysplastic syndrome patients, we show that compaRe can reveal interpatient heterogeneity and recognizable phenotypic profiles. By applying compaRe to high-throughput flow cytometry drug response data in AML models, we robustly identified multiple types of both deep and subtle phenotypic response patterns, highlighting how this analysis could be used for therapeutic discoveries. In conclusion, compaRe is a toolkit that uniquely allows for automated, rapid, and precise comparisons of large-scale multiparameter datasets, including high-throughput screens.
The accumulation of protein structural data occurs more rapidly than it can be characterized by traditional laboratory means. This has motivated widespread efforts to predict enzyme function ...computationally. The most useful/accurate strategies employed to date are based on the detection of motifs in novel structures that correspond to a specific function. Functional residues are critical components of predictively useful motifs. We have implemented a novel method, to complement current approaches, which detects motifs solely on the basis of distance restraints between catalytic residues.
ProMOL is a plugin for the PyMOL molecular graphics environment that can be used to create active site motifs for enzymes. A library of 181 active site motifs has been created with ProMOL, based on definitions published in the Catalytic Site Atlas (CSA). Searches with ProMOL produce better than 50% useful Enzyme Commission (EC) class suggestions for level 1 searches in EC classes 1, 4 and 5, and produce some useful results for other classes. 261 additional motifs automatically translated from Jonathan Barker's JESS motif set Bioinformatics 19:1644-1649, 2003 and a set of NMR motifs is under development. Alignments are evaluated by visual superposition, Levenshtein distance and root-mean-square deviation (RMSD) and are reasonably consistent with related search methods.
The ProMOL plugin for PyMOL provides ready access to template-based local alignments. Recent improvements to ProMOL, including the expanded motif library, RMSD calculations and output selection formatting, have greatly increased the program's usability and speed, and have improved the way that the results are presented.
Huntington’s disease (HD) is characterized by hypomyelination as well as neuronal loss. To assess the basis for myelin loss in HD, we generated bipotential glial progenitor cells (GPCs) from human ...embryonic stem cells (hESCs), derived from huntingtin (mHTT)-mutant embryos or normal controls, and performed RNAseq to assess mHTT-dependent changes in gene expression. In hGPCs derived from 3 mHTT hESC lines, transcription factors associated with glial differentiation and myelin synthesis were sharply down-regulated relative to normal hESC GPCs; NKX2.2, OLIG2, SOX10, MYRF and their downstream targets were all suppressed. Accordingly, when mHTT hGPCs were transplanted into hypomyelinated
shiverer
mice, the resultant glial chimeras were hypomyelinated; this defect could be rescued by forced expression of SOX10 and MYRF by mHTT hGPCs. The mHTT hGPCs also manifested impaired astrocytic differentiation, and developed abnormal fiber architecture. White matter involution in HD is thus a product of the cell autonomous, mHTT-dependent suppression of glial differentiation.
The authors show that glial progenitor cells derived from human ES cells expressing mutant Huntingtin (mHTT) are delayed and defective in their maturation; their suppressed transcription of differentiation-associated genes leads to both astrocytic dysfunction and myelin deficiency in vivo. Glial pathology may thus contribute to disease phenotype in Huntington’s disease.
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ProMOL, an extension for molecular visualization system PyMOL, is structure‐based protein function prediction software. ProMOL implements routines for building motif templates based on ...active sites of proteins of known structure and function and screening unassigned structures for presence of the motif templates. Presently, motif generation in ProMOL requires user intervention in optimization of parameters for sensitivity and selectivity. An algorithm was developed to automate motif building and testing routines of ProMOL. The algorithm uses a set of empirically derived parameters for optimization, requires little user intervention, and provides a possibility for extending the ProMOL library of motif templates at a much higher rate. Presently, the library contains 181 motif templates. As a result of automating motif building and testing routines, 388 motif templates were generated and tested against their native, known homologous, and non‐homologous structures. The automatically generated motif templates exhibited comparable performance to the existing manually generated motif templates in terms of the rates of true positive and true negative results. The research is supported by 2R15GM078077–02.
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