The expression levels of genes on trisomic chromosomes (chromosome 13, 18 or 21) are increased approximately 1.5-fold on average compared with diploid cells
Ontology highlight
ABSTRACT: Phenotypes in chromosome abnormalities do not arise as a mere summation of the specific effects of dosage-sensitive genes, but as a result of the synergistic actions of whole chromosomes. 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: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: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:Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive genetic disorder, first described 1981 in Nijmegen, Holland. The characteristics of NBS include genomic instability (resulting in early onset of malignancies), premature aging, microcephaly and other growth retardations, immune deficiency, and impaired puberty and fertility in females. The consequence of these manifestations is a severe decrease in average life span, caused by cancer or infection of the respiratory and urinary tract. We reprogrammed fibroblasts from NBS patients into induced pluripotent stem cells (iPSCS) to bypass premature senescence and to generate an unlimited cell source for modeling purposes. We screened the influence of antioxidants on intracellular levels of ROS and DNA damage and found that EDHB was able to decrease DNA damage in the presence of high oxidative stress. Furthermore, we found that NBS fibroblasts, but not NBS-iPSCs were more susceptible to the induction of DNA damage than their normal counterparts. We performed global transcriptome analysis comparing NBS to normal fibroblasts and NBS-iPSCs to hESCs. There, we found, that TP53 was activated and cell cycle genes broadly down-regulated in NBS fibroblasts and up-regulation of glycolysis specifically in NBS-iPSCs.
Project description:Nijmegen Breakage Syndrome (NBS) is a rare autosomal recessive genetic disorder, first described 1981 in Nijmegen, Holland. The characteristics of NBS include genomic instability (resulting in early onset of malignancies), premature aging, microcephaly and other growth retardations, immune deficiency, and impaired puberty and fertility in females. The consequence of these manifestations is a severe decrease in average life span, caused by cancer or infection of the respiratory and urinary tract. We reprogrammed fibroblasts from NBS patients into induced pluripotent stem cells (iPSCS) to bypass premature senescence and to generate an unlimited cell source for modeling purposes. We screened the influence of antioxidants on intracellular levels of ROS and DNA damage and found that EDHB was able to decrease DNA damage in the presence of high oxidative stress. Furthermore, we found that NBS fibroblasts, but not NBS-iPSCs were more susceptible to the induction of DNA damage than their normal counterparts. We performed global transcriptome analysis comparing NBS to normal fibroblasts and NBS-iPSCs to hESCs. There, we found, that TP53 was activated and cell cycle genes broadly down-regulated in NBS fibroblasts and up-regulation of glycolysis specifically in NBS-iPSCs.
Project description:Background:Human aneuploidy is the leading cause of early pregnancy loss, mental retardation, and multiple congenital anomalies. Due to the high mortality associated with aneuploidy, the pathophysiological mechanisms of aneuploidy syndrome remain largely unknown. Previous studies focused mostly on whether dosage compensation occurs, and the next generation transcriptomics sequencing technology RNA-seq is expected to eventually uncover the mechanisms of gene expression regulation and the related pathological phenotypes in human aneuploidy. Results:Using next generation transcriptomics sequencing technology RNA-seq, we profiled the transcriptomes of four human aneuploid induced pluripotent stem cell (iPSC) lines generated from monosomy X (Turner syndrome), trisomy 8 (Warkany syndrome 2), trisomy 13 (Patau syndrome), and partial trisomy 11:22 (Emanuel syndrome) as well as two umbilical cord matrix iPSC lines as euploid controls to examine how phenotypic abnormalities develop with aberrant karyotype. A total of 466 M (50-bp) reads were obtained from the six iPSC lines, and over 13,000 mRNAs were identified by gene annotation. Global analysis of gene expression profiles and functional analysis of differentially expressed (DE) genes were implemented. Over 5000 DE genes are determined between aneuploidy and euploid iPSCs respectively while 9 KEGG pathways are overlapped enriched in four aneuploidy samples. Conclusions:Our results demonstrate that the extra or missing chromosome has extensive effects on the whole transcriptome. Functional analysis of differentially expressed genes reveals that the genes most affected in aneuploid individuals are related to central nervous system development and tumorigenesis. Four aneuploid iPSC (trisomy 8, trisomy 13, partial trisomy 11:22, monosomy X) and two euploid iPSC mRNA profiles were generated by deep sequencing, using SOLiD v3 platform. Gene expression values were compared.
Project description:To increase our understanding of epigenetic patterns associated with aneuploidy we used constitutional trisomy 8 mosaicism as a model, enabling analyses of single cell clones, harboring either trisomy or disomy 8, from the same patient. We profiled gene and miRNA expression as well as genome-wide and promoter specific DNA methylation and hydroxymethylation patterns in trisomic and disomic fibroblasts, using microarrays and methylated DNA immunoprecipitation. comparison of trisomy 8 cells with disomic as well as reference fibroblasts
Project description:To increase our understanding of epigenetic patterns associated with aneuploidy we used constitutional trisomy 8 mosaicism as a model, enabling analyses of single cell clones, harboring either trisomy or disomy 8, from the same patient. We profiled gene and miRNA expression as well as genome-wide and promoter specific DNA methylation and hydroxymethylation patterns in trisomic and disomic fibroblasts, using microarrays and methylated DNA immunoprecipitation. comparison of trisomy 8 cells with disomic as well as reference fibroblasts
Project description:To increase our understanding of epigenetic patterns associated with aneuploidy we used constitutional trisomy 8 mosaicism as a model, enabling analyses of single cell clones, harboring either trisomy or disomy 8, from the same patient. We profiled gene and miRNA expression as well as genome-wide and promoter specific DNA methylation and hydroxymethylation patterns in trisomic and disomic fibroblasts, using microarrays and methylated DNA immunoprecipitation. comparison of trisomy 8 cells with disomic as well as reference fibroblasts
Project description:Premature aging is a hallmark of Down syndrome, caused by trisomy of human chromosome 21; but the reason is unclear and difficult to study in humans. We used an aneuploid model in wild yeast to show that chromosome amplification disrupts nutrient-induced cell-cycle arrest, quiescence entry, and healthy aging, across genetic backgrounds and amplified chromosomes. We discovered that these defects are due in part to aneuploidy-induced dysfunction in Ribosome Quality Control (RQC). Aneuploids entering quiescence display aberrant ribosome profiles, accumulate RQC intermediates, and harbor an increased load of protein aggregates. Although they have normal proteasome capacity, aneuploids show signs of ubiquitin dysregulation, which impacts cyclin abundance to disrupt arrest. Remarkably, inducing ribosome stalling in euploids produces similar aberrations, while up-regulating limiting RQC subunits or proteins in ubiquitin metabolism alleviates many of the aneuploid defects. Our results raise major implications for other aneuploidy disorders including Down syndrome.
Project description:Premature aging is a hallmark of Down syndrome, caused by trisomy of human chromosome 21; but the reason is unclear and difficult to study in humans. We used an aneuploid model in wild yeast to show that chromosome amplification disrupts nutrient-induced cell-cycle arrest, quiescence entry, and healthy aging, across genetic backgrounds and amplified chromosomes. We discovered that these defects are due in part to aneuploidy-induced dysfunction in Ribosome Quality Control (RQC). Aneuploids entering quiescence display aberrant ribosome profiles, accumulate RQC intermediates, and harbor an increased load of protein aggregates. Although they have normal proteasome capacity, aneuploids show signs of ubiquitin dysregulation, which impacts cyclin abundance to disrupt arrest. Remarkably, inducing ribosome stalling in euploids produces similar aberrations, while up-regulating limiting RQC subunits or proteins in ubiquitin metabolism alleviates many of the aneuploid defects. Our results raise major implications for other aneuploidy disorders including Down syndrome.