Down syndrome (DS) is the leading genetic cause of mental retardation and is caused by a third copy of human chromosome 21. The different pathologies of DS involve many tissues with a distinct array of neural phenotypes. Here we characterize new embryonic stem cell lines with DS (DS-ESCs), and focus on the neural aspects of the diease. Our results show that neural progenitor cells (NPCs) differentiated from five independent DS-ESC lines display increased apoptosis and down-regulation of forehead developmental genes. Analysis of differentially expressed genes suggested RUNX1 as a key transcription regulator in DS-NPCs. Using genome editing we were able to disrupt all three copies of RUNX1 in DS-ESCs, leading to down-regulation of several RUNX1 target developmental genes accompanied by reduced apoptosis and neuron migration. Our work sheds new light on the role of RUNX1 and the importance of dosage balance in the development of neural phenotypes in DS.
Molecular Characterization of Down Syndrome Embryonic Stem Cells Reveals a Role for RUNX1 in Neural Differentiation.
Sex, Specimen part
View SamplesHuman pluripotent stem cells (hPSCs) tend to acquire chromosomal aberrations in culture, which may increase their tumorigenicity. However, the cellular mechanism(s) underlying these aberrations are largely unknown. Here we show that the DNA replication in aneuploid hPSCs is perturbed, resulting in high prevalence of defects in chromosome condensation and segregation. Global gene expression analyses in aneuploid hPSCs revealed decreased levels of actin cytoskeleton genes and their common transcription factor SRF. Down-regulation of SRF or chemical perturbation of actin cytoskeleton organization in diploid hPSCs resulted in increased replication stress and perturbation of chromosome condensation, recapitulating the findings in aneuploid hPSCs. Altogether, our results revealed that in hPSCs DNA replication stress results in a distinctive defect in chromosome condensation, underlying their ongoing chromosomal instability. Our results shed a new light on the mechanisms leading to ongoing chromosomal instability in hPSCs, and may be relevant to tumor development as well.
Genomic Instability in Human Pluripotent Stem Cells Arises from Replicative Stress and Chromosome Condensation Defects.
Specimen part, Cell line
View SamplesDiploidy is a fundamental genetic feature in mammals, in which haploid cells normally arise only as post-meiotic germ cells that serve to insure a diploid genome upon fertilization. Gamete manipulation has yielded haploid embryonic stem (ES) cells from several mammalian species, but as of yet not from humans. Here we analyzed a large collection of human parthenogenetic ES cell lines originating from haploid oocytes, leading to the successful isolation and maintenance of human ES cell lines with a normal haploid karyotype. Haploid human ES cells exhibited typical pluripotent stem cell characteristics such as self-renewal capacity and a pluripotency-specific molecular signature. Although haploid human ES cells resembled their diploid counterparts, they also displayed distinct properties including differential regulation of X chromosome inactivation and genes involved in oxidative phosphorylation, alongside reduction in absolute gene expression levels and cell size. Intriguingly, we found that a haploid genome is compatible not only with the undifferentiated pluripotent state, but also with differentiated somatic fates representing all three embryonic germ layers, despite a persistent dosage imbalance between the autosomes and X chromosome. We expect that haploid human ES cells will provide novel means for studying human functional genomics, development and evolution. Overall design: RNA sequencing analysis was performed on a total of 2 samples of in vitro fertilization (IVF) control embryonic stem cell lines.
Derivation and differentiation of haploid human embryonic stem cells.
No sample metadata fields
View SamplesDiploidy is a fundamental genetic feature in mammals, in which haploid cells normally arise only as post-meiotic germ cells that serve to insure a diploid genome upon fertilization. Gamete manipulation has yielded haploid embryonic stem (ES) cells from several mammalian species, but as of yet not from humans. Here we analyzed a large collection of human parthenogenetic ES cell lines originating from haploid oocytes, leading to the successful isolation and maintenance of human ES cell lines with a normal haploid karyotype. Haploid human ES cells exhibited typical pluripotent stem cell characteristics such as self-renewal capacity and a pluripotency-specific molecular signature. Although haploid human ES cells resembled their diploid counterparts, they also displayed distinct properties including differential regulation of X chromosome inactivation and genes involved in oxidative phosphorylation, alongside reduction in absolute gene expression levels and cell size. Intriguingly, we found that a haploid genome is compatible not only with the undifferentiated pluripotent state, but also with differentiated somatic fates representing all three embryonic germ layers, despite a persistent dosage imbalance between the autosomes and X chromosome. We expect that haploid human ES cells will provide novel means for studying human functional genomics, development and evolution.
Derivation and differentiation of haploid human embryonic stem cells.
Specimen part, Cell line
View SamplesHuman pluripotent stem cells (hPSCs) tend to acquire genomic aberrations in culture, the most common of which is the trisomy of chromosome 12. Interestingly, trisomy 12 is also prevalent in germ cell tumors (GCTs). Here, we aimed to dissect the cellular and molecular implications of trisomy 12 in hPSCs. A genome-wide gene expression analysis revealed that trisomy 12 profoundly affects the global gene expression profile of hPSCs, inducing a transcriptional program very similar to that of CGTs. Direct comparison of the proliferation, replication, differentiation and apoptosis between diploid and aneuploid hPSCs revealed that trisomy 12 significantly increases the proliferation rate of hPSCs. Increased replication largely accounts for the increased proliferation observed, and may explain the selection advantage that trisomy 12 confers to hPSCs. A comparison of the tumors induced by diploid and aneuploid hPSCs further demonstrated that trisomy 12 increases the tumorigenicity of hPSCs, inducing transcriptionally-distinct teratomas, from which pluripotent cells can be recovered. Lastly, a chemical screen of 89 anticancer drugs against diploid and aneuploid hPSCs discovered that trisomy 12 raises the sensitivity of hPSCs to several replication inhibitors, suggesting that the increased proliferation and tumorigenicity of these aberrant cells also makes them more vulnerable, and might potentially be used for their selective elimination from culture. Together, our findings demonstrate the extensive effect of trisomy 12 on the gene expression signature and on the cellular behavior of hPSCs, and highlight the danger posed by this trisomy for the successful use of hPSCs in basic research and in regenerative medicine.
Aneuploidy induces profound changes in gene expression, proliferation and tumorigenicity of human pluripotent stem cells.
Specimen part, Cell line
View SamplesThe use of human pluripotent stem cells (hPSCs) in cell therapy is hindered by the tumorigenic risk from residual undifferentiated cells. Here we performed a high-throughput screen of over 52,000 small molecules, and identified 15 highly selective cytotoxic inhibitors of hPSCs (PluriSIns). Cellular and molecular analyses revealed that the most selective compound, PluriSIn #1, is a pluripotent-specific inhibitor of stearoyl-coA desaturase (SCD1), the key enzyme in the biosynthesis of monounsaturated fatty acids (MUFA). SCD1 inhibition in hPSCs induced ER stress, protein synthesis attenuation, and apoptosis of these cells, revealing that MUFA biosynthesis is crucial for their survival. PluriSIn #1 was also cytotoxic toward the ICM cells of mouse embryos, indicating that the dependence on SCD1 is inherent to the pluripotent state. Finally, application of PluriSIn #1 prevented teratoma formation from tumorigenic undifferentiated cells. Our novel method to eliminate undifferentiated cells from culture should thus increase the safety of hPSC-based treatments.
Selective elimination of human pluripotent stem cells by an oleate synthesis inhibitor discovered in a high-throughput screen.
Specimen part, Cell line, Treatment
View SamplesHuman pluripotent stem cells can be derived from somatic cells by forced expression of defined factors, and more recently by nuclear-transfer into human oocytes, revitalizing a debate on whether one reprogramming approach might be advantageous over the other. Here we compared the genetic and epigenetic stability of human nuclear-transfer embryonic stem cell (NT-ESC) lines and isogenic induced pluripotent stem cell (iPSC) lines, derived from the same somatic cell cultures of fetal, neonatal and adult origin. Both cell types shared similar genome-wide gene expression and DNA methylation profiles. Importantly, NT-ESCs and iPSCs have comparable numbers of de novo coding mutations but significantly higher than parthenogenetic ESCs. Similar to iPSCs NT-ESCs displayed clone- and gene-specific aberrations in DNA methylation and allele-specific expression of imprinted genes, similarly to iPSCs. The occurrence of these genetic and epigenetic defects in both NT-ESCs and iPSCs suggests that they are inherent to reprogramming, regardless of the underlying technique. Overall design: RNA sequencing analysis was performed on a total of 12 human cell lines, including: an isogenic set of 3 nuclear-transfer embryonic stem cell (NT-ESC) lines, 2 RNA-reprogrammed induced pluripotent stem cell (iPSC) lines and their parental neonatal fibroblast cell line; an isogenic set of 1 NT-ESC line, 3 iPSC lines and their parental adult fibroblast cell line (derived from a type 1 diabetic subject); as well as 1 control embryonic stem cell (ESC) line.
Comparable frequencies of coding mutations and loss of imprinting in human pluripotent cells derived by nuclear transfer and defined factors.
No sample metadata fields
View SamplesNoncoding variants play a central role in the genetics of complex traits, but we still lack a full description of the main molecular pathways through which they act. Here we used molecular data to quantify the contribution of cis-acting genetic effects at each major stage of gene regulation from chromatin to proteins, within a population sample of Yoruba lymphoblastoid cell lines (LCLs). We performed 4sU metabolic labeled transcripts in 65 YRI LCLs to identify genetic variants that affect transcription rates. As expected, we found an important contribution of genetic variation via chromatin, contributing ~65% of eQTLs (expression Quantitative Trait Loci). The remaining eQTLs, which are not asso- ciated with chromatin-level variation, are highly enriched in transcribed regions, and hence may affect expression through co- or post-transcriptional processes. Overall design: International HapMap lymphoblastoid cell lines (LCLs) derived from YRI (Yoruba in Ibadan, Nigeria); We adapted the 4sU labelling method from (PMID 21516085). Briefly, cell cultures were grown to log phase in volumes sufficient to yield about 300 ng of 4sU-labeled RNA. Cells were incubated with 4sU for the required length of time (0, 30, or 60 minutes), then washed, pelleted, and frozen. Total RNA was extracted, and 4sU-labeled RNA was separated from total RNA using a bead-based biotin-streptavidin purification protocol. We sequenced metabolic labeled transcripts in 65 YRI LCLs 30 minutes and 60 minutes after incubation.
RNA splicing is a primary link between genetic variation and disease.
No sample metadata fields
View SamplesCancer stem cell (CSC) identification relies on transplantation assays of cell sub-populations sorted from fresh tumor samples. Herein, we attempt to bypass limitations of abundant tumor source and predetermined immune selection by in-vivo propagating patient derived xenografts (PDX) from human malignant rhabdoid tumor (MRT), a rare and lethal pediatric neoplasm, to an advanced state in which most cells behave as CSCs. Stemness is then probed by comparative transcriptomics of serial PDXs generating a gene signature of EMT, invasion/motility, metastasis and self-renewal, pinpointing putative MRT CSC markers. The relevance of these putative CSC molecules is analyzed by sorting tumorigenic fractions from early-passaged PDX according to one such molecule, deciphering expression in archived primary tumors and testing the effects of CSC molecule inhibition on MRT growth. Using this platform, we identify ALDH1 and lysyl oxidase (LOX) as relevant targets and provide a larger framework for target and drug discovery in rare pediatric cancers. Overall design: Tumorigenic fractions from early-passaged PDX
In Vivo Expansion of Cancer Stemness Affords Novel Cancer Stem Cell Targets: Malignant Rhabdoid Tumor as an Example.
Subject
View SamplesAlthough nuclear transfer allows the reprogramming of somatic cells to totipotency, little is known concerning the kinetics by which it takes place or the minimum requirements for its success. Here, we demonstrate that reprogramming can be achieved within a few hours and a single cell-cycle as long as two key constraints on reprogramming are satisfied. First, the recipient cell chromosomes must be removed during mitosis. Second, the nuclear envelope of the donor cell must be broken down and its chromosomes condensed, allowing an embryonic nucleus to be constructed around the incoming chromosomes. If these requirements are not met, then reprogramming fails and embryonic development arrests. These results point to a central role for processes intimately linked to cell division in mediating efficient transitions between transcriptional programs.
Reprogramming within hours following nuclear transfer into mouse but not human zygotes.
Specimen part
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