Project description:An extra copy of chromosome 21 causes Down syndrome, the most common genetic disease in humans. The mechanisms contributing to aneuploidy-related pathologies in this syndrome, independent of the identity of the triplicated genes, are not well defined. To characterize aneuploidy-driven phenotypes in trisomy 21 cells, we performed global transcriptome, proteome, and phenotypic analyses of primary human fibroblasts from individuals with Patau (trisomy 13), Edwards (trisomy 18), or Down syndromes. On average, mRNA and protein levels were increased by 1.5-fold in all trisomies, with a subset of proteins enriched for subunits of macromolecular complexes showing signs of posttranscriptional regulation. These results support the lack of evidence for widespread dosage compensation or dysregulation of chromosomal domains in human autosomes. Furthermore, we show that several aneuploidy-associated phenotypes are present in trisomy 21 cells, including lower viability and increased dependency on serine-driven lipid synthesis. Our studies establish a critical role of aneuploidy, independent of triplicated gene identity, in driving cellular defects associated with trisomy 21.
Project description:To characterize aneuploidy driven phenotypes in human trisomies, we performed global transcriptome, proteome, and phenotypic analysis of primary human fibroblasts from individuals with Patau (trisomy 13), Edwards (trisomy 18), or Down syndromes.
Project description:Down syndrome (DS) is caused by an extra copy of chromosome 21. We are characterizing protein changes in human skin fibroblasts. We propose to study corresponding changes at the DNA level (by SNP analysis) and the RNA level (using Affymetrix chips). These studies will detail transcriptional and translational regulation in trisomy. The Specific Aim is to obtain data on RNA transcript levels using Affymetrix expression arrays in a group of trisomy 21 and euploid fibroblast cell lines. In parallel, we will acquire SNP data to determine both genotype (call) and copy number changes for trisomic samples. The results will allow us to identify the patterns of change in a trisomic chromosome (relative to control). [1] We hypothesize that in genomic DNA samples derived from trisomy 21 (TS21) fibroblasts there will be an increased copy number on chr21 with additional microdeletions and microdeletions. [2] We hypothesize that the RNA transcripts derived from chr21 will be elevated relative to euploid controls. [3] We hypothesize that altered RNA transcript levels will be significantly correlated with altered protein levels from these same fibroblast cell lines. The experimental design is as follows. All samples are from deidentified individuals and were obtained from the Brain and Tissue Bank for Developmental Disorders at the University of Maryland, with Johns Hopkins IRB approval.[1] There are five trisomy 21 samples and five euploid samples (total n=10). Fibroblasts were grown in culture to comparable confluency and passage number. Cells were harvested. Total RNA was isolated with a Qiagen kit. The quantity and purity of the RNA was confirmed by spectrophotometry and by electrophoresing an aliquot on a 1% agarose gel. Approximately 10 micrograms of total RNA will be sent to TGen on dry ice for analysis on Affymetrix U133 PlusTwo arrays. Data analysis will be with Affymetrix and Partek software. Keywords: other
Project description:Down syndrome (DS) is caused by an extra copy of chromosome 21. We are characterizing protein changes in human skin fibroblasts. We propose to study corresponding changes at the DNA level (by SNP analysis) and the RNA level (using Affymetrix chips). These studies will detail transcriptional and translational regulation in trisomy. The Specific Aim is to obtain data on RNA transcript levels using Affymetrix expression arrays in a group of trisomy 21 and euploid fibroblast cell lines. In parallel, we will acquire SNP data to determine both genotype (call) and copy number changes for trisomic samples. The results will allow us to identify the patterns of change in a trisomic chromosome (relative to control). [1] We hypothesize that in genomic DNA samples derived from trisomy 21 (TS21) fibroblasts there will be an increased copy number on chr21 with additional microdeletions and microdeletions. [2] We hypothesize that the RNA transcripts derived from chr21 will be elevated relative to euploid controls. [3] We hypothesize that altered RNA transcript levels will be significantly correlated with altered protein levels from these same fibroblast cell lines. The experimental design is as follows. All samples are from deidentified individuals and were obtained from the Brain and Tissue Bank for Developmental Disorders at the University of Maryland, with Johns Hopkins IRB approval.[1] There are five trisomy 21 samples and five euploid samples (total n=10). Fibroblasts were grown in culture to comparable confluency and passage number. Cells were harvested. Total RNA was isolated with a Qiagen kit. The quantity and purity of the RNA was confirmed by spectrophotometry and by electrophoresing an aliquot on a 1% agarose gel. Approximately 10 micrograms of total RNA will be sent to TGen on dry ice for analysis on Affymetrix U133 PlusTwo arrays. Data analysis will be with Affymetrix and Partek software.
Project description:IntroductionDown syndrome, caused by trisomy 21, is a complex developmental disorder associated with intellectual disability and reduced growth of multiple organs. Structural pathologies are present at birth, reflecting embryonic origins. A fundamental unanswered question is how an extra copy of human chromosome 21 contributes to organ-specific pathologies that characterize individuals with Down syndrome, and, relevant to the hallmark intellectual disability in Down syndrome, how trisomy 21 affects neural development. We tested the hypothesis that trisomy 21 exerts effects on human neural development as early as neural induction.MethodsBulk RNA sequencing was performed on isogenic trisomy 21 and euploid human induced pluripotent stem cells (iPSCs) at successive stages of neural induction: embryoid bodies at Day 6, early neuroectoderm at Day 10, and differentiated neuroectoderm at Day 17.ResultsGene expression analysis revealed over 1,300 differentially expressed genes in trisomy 21 cells along the differentiation pathway compared to euploid controls. Less than 5% of the gene expression changes included upregulated chromosome 21 encoded genes at every timepoint. Genes involved in specific growth factor signaling pathways (WNT and Notch), metabolism (including oxidative stress), and extracellular matrix were altered in trisomy 21 cells. Further analysis uncovered heterochronic expression of genes.ConclusionTrisomy 21 impacts discrete developmental pathways at the earliest stages of neural development. The results suggest that metabolic dysfunction arises early in embryogenesis in trisomy 21 and may affect development and function more broadly.
Project description:Chromosome abnormalities induces profound alterations in gene expression, leading to various disease phenotypes. Recent studies on yeast and mammalian cells have demonstrated that aneuploidy exerts detrimental effects on organismal growth and development, regardless of the karyotype, suggesting that aneuploidy-associated stress plays an important role in disease pathogenesis. However, whether and how this effect alters cellular homeostasis and long-term features of human disease are not fully understood. Here, we aimed to investigate cellular stress responses in human trisomy syndromes, using fibroblasts and induced pluripotent stem cells (iPSCs). Dermal fibroblasts derived from patients with trisomy 21, 18 and 13 showed a severe impairment of cell proliferation and enhanced premature senescence. These phenomena were accompanied by perturbation of protein homeostasis, leading to the accumulation of protein aggregates. We found that treatment with sodium 4-phenylbutyrate (4-PBA), a chemical chaperone, decreased the protein aggregates in trisomy fibroblasts. Notably, 4-PBA treatment successfully prevented the progression of premature senescence in secondary fibroblasts derived from trisomy 21 iPSCs. Our study reveals aneuploidy-associated stress as a potential therapeutic target for human trisomies, including Down syndrome.
Project description:An abnormal number of chromosomes, or aneuploidy, accounts for most spontaneous abortions, causes developmental defects, and is associated with aging and cancer. The molecular mechanisms by which aneuploidy disrupts cellular function remain largely unknown. Here, we show that aneuploidy disrupts the morphology of the nucleus. Mutations that increase the levels of long-chain bases suppress nuclear abnormalities of aneuploid yeast independent of karyotype identity. Quantitative lipidomics indicates that long-chain bases are integral components of the nuclear membrane in yeast. Cells isolated from patients with Down syndrome also show that abnormal nuclear morphologies and increases in long-chain bases not only suppress these abnormalities but also improve their fitness. We obtained similar results with cells isolated from patients with Patau or Edward syndrome, indicating that increases in long-chain bases improve the fitness of aneuploid cells in yeast and humans. Targeting lipid biosynthesis pathways represents an important strategy to suppress nuclear abnormalities in aneuploidy-associated diseases.
Project description:Trisomy of human chromosome 21 (T21) gives rise to Down syndrome, the most frequent life-born autosomal aneuploidy. To enable in vitro analyses of the cellular and moelcular mechanisms leading to the neurological alterations associated with T21, we created and characterized a panel of genomically diverse T21 and euploid induced pluripotent stem cells (iPSCs) from fibroblasts obtained from the Coriell Institute for Biomedical Research, and we then differentiated these iPSCs into neural progenitor cells (NPCs). Microarray transcriptomic analyses were performed on this panel of fibroblasts, iPSCs, and NPCs, identifying genes and pathways that were altered in T21 lines relative to euploid as well as genes and pathways in NPCs that showed inter-individual variability.
Project description:Down syndrome, caused by trisomy 21, is a complex developmental disorder associated with intellectual disability and reduced growth of multiple organs. Structural pathologies are present at birth, reflecting embryonic origins. A fundamental unanswered question is how an extra copy of human chromosome 21 contributes to organ-specific pathologies that characterize individuals with Down syndrome. Relevant to the hallmark intellectual disability in Down syndrome, how does trisomy 21 affect neural development? We tested the hypothesis that trisomy 21 exerts effects on human neural development as early as neural induction. Bulk RNA sequencing was performed on isogenic trisomy 21 and euploid human induced pluripotent stem cells (iPSCs) at successive stages of neural induction: embryoid bodies at Day 6, early neuroectoderm at Day 10, and differentiated neuroectoderm at Day 17. Gene expression analysis revealed over 1,300 differentially expressed genes in trisomy 21 cells along the differentiation pathway compared to euploid controls. Less than 5% of the gene expression changes included upregulated chromosome 21 encoded genes at every timepoint. Genes involved in specific growth factor signaling pathways (Wnt and Notch), metabolism (including interferon response and oxidative stress), and extracellular matrix were altered in trisomy 21 cells. Further analysis revealed heterochronic expression of genes. This comprehensive analysis reveals that trisomy 21 impacts discrete developmental pathways at the earliest stages of neural development. Further, the results suggest that metabolic dysfunction arises early in embryogenesis in trisomy 21 and may thus affect development and function more broadly.