Project description:CHARGE syndrome is caused by heterozygous mutations in a chromatin remodeler CHD7 and characterized by a set of malformations historically postulated to arise from defects in the neural crest formation during embryogenesis. To better delineate neural crest defects in CHARGE syndrome, we generated induced pluripotent stem cells (iPSCs) from two patients with typical syndrome manifestations, and characterized neural crest cells differentiated in vitro from these iPSCs (iPSC-NCCs). We found that expression of genes associated with cell migration was altered in CHARGE iPSC-NCCs as compared to control iPSC-NCCs. Consistently, CHARGE iPSC-NCCs showed defective delamination, migration and motility in vitro, and their transplantation in ovo revealed overall defective migratory activity in the chick embryo. Altogether, our results support the historical inference that CHARGE syndrome patients have defects in neural crest migration and provide the first successful application of patient-derived iPSCs in modeling craniofacial disorders.
Project description:Heterozygous loss-of function mutations in CHD7 (chromodomain helicase DNA-binding protein 7) lead to CHARGE syndrome, a complex developmental disorder affecting craniofacial structures, peripheral nerves and several organ systems like eyes, ears, nose and heart. Recently, it was demonstrated that CHD7 is essential for the formation of multipotent migratory neural crest cells, which migrate from the neural tube to many regions of the embryo, where they differentiate into various tissues including craniofacial and heart structures. So far only few CHD7 target genes involved in neural crest cell development have been identified and the role of CHD7 in neural crest cell guidance and the regulation of mesenchymal-epithelial transition is unknown. Therefore, we undertook a genome-wide microarray expression analysis on wild-type and CHD7 deficient (Chd7Whi/+ and Chd7Whi/Whi) mouse embryos at day 9.5, the time point of neural crest cell migration. We identified 98 genes showing greater than two fold differences in expression (log2 fold-change) and a P-value to false discovery rate (FDR) < 0.05 between wild-type and Chd7Whi/Whi embryos. Interestingly, many misregulated genes are involved in neural crest cell and axon guidance like semaphorins and ephrin receptors. By performing knockdown experiments for Chd7 and one of its target genes, namely semaphorin3a in Xenopus laevis embryos, we could show abnormalities in the migration of neural crest cells in vivo. Additionally, we detected non-synonymous SEMA3A variations in 3 out of 45 CHD7 negative CHARGE patients suggesting a role for SEMA3A in the pathogenesis of CHARGE syndrome. To identify genes that are affected by the absence of functional Chd7 at the time point of neural crest cell migration, the expression profiles of E9.5 wild-type, Chd7Whi/+ and Chd7Whi/Whi female mouse embryos were compared by whole-genome microarray analysis. Mouse embryos of the same sex were used to avoid sex-dependent gene expression effects. We performed microarray analysis by using the Agilent-026655 Whole Mouse Genome Microarray 4x44K v2 (Agilent) on four biological replicates from each group.
Project description:Heterozygous loss-of function mutations in CHD7 (chromodomain helicase DNA-binding protein 7) lead to CHARGE syndrome, a complex developmental disorder affecting craniofacial structures, peripheral nerves and several organ systems like eyes, ears, nose and heart. Recently, it was demonstrated that CHD7 is essential for the formation of multipotent migratory neural crest cells, which migrate from the neural tube to many regions of the embryo, where they differentiate into various tissues including craniofacial and heart structures. So far only few CHD7 target genes involved in neural crest cell development have been identified and the role of CHD7 in neural crest cell guidance and the regulation of mesenchymal-epithelial transition is unknown. Therefore, we undertook a genome-wide microarray expression analysis on wild-type and CHD7 deficient (Chd7Whi/+ and Chd7Whi/Whi) mouse embryos at day 9.5, the time point of neural crest cell migration. We identified 98 genes showing greater than two fold differences in expression (log2 fold-change) and a P-value to false discovery rate (FDR) < 0.05 between wild-type and Chd7Whi/Whi embryos. Interestingly, many misregulated genes are involved in neural crest cell and axon guidance like semaphorins and ephrin receptors. By performing knockdown experiments for Chd7 and one of its target genes, namely semaphorin3a in Xenopus laevis embryos, we could show abnormalities in the migration of neural crest cells in vivo. Additionally, we detected non-synonymous SEMA3A variations in 3 out of 45 CHD7 negative CHARGE patients suggesting a role for SEMA3A in the pathogenesis of CHARGE syndrome.
Project description:Neurocristopathies such as CHARGE syndrome result from aberrant neural crest development. A large proportion of CHARGE cases are attributed to pathogenic variants in the gene encoding CHD7, chromodomain helicase DNA binding protein 7, which remodels chromatin. While the role for CHD7 in neural crest development is well documented, how this factor is specifically upregulated in neural crest cells is not understood. Here, we use epigenomic profiling of chick and human neural crest to identify a cohort of enhancers regulating Chd7 expression in neural crest cells and other tissues. We functionally validate upstream transcription factor binding at candidate enhancers, revealing novel epistatic relationships between neural crest master regulators and Chd7, showing tissue-specific regulation of a globally-acting chromatin remodeller for the first time. Furthermore, we find conserved enhancer features in human embryonic epigenomic data and validate the activity of the human equivalent CHD7 enhancers in the chick embryo. Our findings embed Chd7 in the neural crest gene regulatory network and offer potentially clinically relevant elements for interpreting CHARGE syndrome cases without causative allocation.
Project description:Neurocristopathies such as CHARGE syndrome result from aberrant neural crest development. A large proportion of CHARGE cases are attributed topathogenic variantsin the gene encoding CHD7, chromodomain helicase DNA binding protein 7, which remodels chromatin. While the role for CHD743in neural crest development is well documented,how this factor is specifically upregulated in neural crest cells is not understood. Here, we use epigenomic profiling of chick and human neural crest to identify a cohort of enhancers regulating Chd7 expression in neural crest cells and other tissues. We functionally validate upstream transcription factor binding at candidate enhancers, revealing novel epistatic relationships between neural crest master regulators and Chd7, showing tissue-specific regulation of a globally-acting chromatin remodeller for the first time. Furthermore, we find conserved enhancer features in human embryonic epigenomic data and validate the activity of the human equivalent CHD7 enhancers in the chick embryo. Our findings embed Chd7 in the neural crest gene regulatory network and offer potentially clinically relevant elements for interpreting CHARGE syndrome cases without causative allocation.
Project description:Neurocristopathies such as CHARGE syndrome result from aberrant neural crest development. A large proportion of CHARGE cases are attributed topathogenic variantsin the gene encoding CHD7, chromodomain helicase DNA binding protein 7, which remodels chromatin. While the role for CHD743in neural crest development is well documented,how this factor is specifically upregulated in neural crest cells is not understood. Here, we use epigenomic profiling of chick and human neural crest to identify a cohort of enhancers regulating Chd7 expression in neural crest cells and other tissues. We functionally validate upstream transcription factor binding at candidate enhancers, revealing novel epistatic relationships between neural crest master regulators and Chd7, showing tissue-specific regulation of a globally-acting chromatin remodeller for the first time. Furthermore, we find conserved enhancer features in human embryonic epigenomic data and validate the activity of the human equivalent CHD7 enhancers in the chick embryo. Our findings embed Chd7 in the neural crest gene regulatory network and offer potentially clinically relevant elements for interpreting CHARGE syndrome cases without causative allocation.
Project description:We performed a microarray experiment to analyze the transcriptional profile of CHARGE patient iPSC-derived neural stem/progenitor cells to identify CHD7 target genes.
Project description:Global gene expression analysis of FD-iPSC and deribved neural crest cells Here we report the derivation of patient specific Familial Dysautonomia-iPSCs and their directed differentiation into multiple cell types capable of modeling the tissue specific splicing defect in vitro. Undifferentiated hESCs were exposed to control and drug treatments for 24 hours followed by mRNA expression analysis Global gene expression analysis of FD-iPSC and derived neural crest cells
Project description:CHARGE syndrome, primarily caused by CHD7 haploinsufficiency, is a complex developmental disorder frequently associated with congenital heart defects. Our comprehensive single-cell RNA sequencing analysis of cardiac neural crest cells (cNCCs) with Chd7 inactivation reveals impaired myocyte differentiation by cNCCs as a major cellular defect; loss of Chd7 disrupts myogenic transcriptional programs, alters cell fate trajectories, and activates cellular stress responses. These results significantly advance our understanding of the NCC-autonomous role of CHD7 and the mechanisms underlying CHARGE-associated heart defects driven by cNCC dysfunction. We further discovered that CHD7 enhances its own expression through interaction with SOX5 at an upstream, evolutionarily conserved enhancer. Notably, SOX5 overexpression in cultured Chd7-haploinsufficient cNCCs restores Chd7 expression from the intact allele, and rescues myocyte differentiation. These findings uncover a SOX5-mediated Chd7 autoregulatory mechanism and suggest that enhancing the SOX5-CHD7 axis may represent a promising strategy to mitigate cardiovascular defects caused by CHD7 insufficiency.
Project description:Global gene expression analysis of FD-iPSC and deribved neural crest cells Here we report the derivation of patient specific Familial Dysautonomia-iPSCs and their directed differentiation into multiple cell types capable of modeling the tissue specific splicing defect in vitro.