The transcriptome of the three atino80 allelic mutants was compared to that of wild-type and 50B Arabidopsis plants (see Fritsch et al. 2004). Since the transcriptomes of 50B and wild-type plants were found to be identical, we compared expression in the mutant with 50B and with wild-type without distinction. Therefore, we had four replicates of the wild type condition (50B line, wild-type) and two replicates for each of the mutant alleles (atino80-1, atino80-2 and atino80-3), all ecotype Columbia. All lines were profiled in duplicate (grown independently at 2-week-intervals).
The INO80 protein controls homologous recombination in Arabidopsis thaliana.
Age, Specimen partView Samples
The tumorigenicity of human pluripotent stem cells (hPSCs) is a major safety concern for their application in regenerative medicine. Here we identify the tight-junction protein Claudin-6 as a specific cell surface marker of hPSCs that can be used to selectively remove Claudin-6-positive cells from mixed cultures. We show that Claudin-6 is absent in adult tissues but highly expressed in undifferentiated cells, where it is dispensable for hPSC survival and self-renewal. We use three different strategies to remove Claudin-6-positive cells from mixed populations: an antibody against Claudin-6; a cytotoxin-conjugated antibody that selectively targets undifferentiated cells; and clostridium perfringens enterotoxin, a toxin that binds several Claudins, including Claudin-6, and efficiently kills undifferentiated cells, thus eliminating the tumorigenic potential of hPSC-containing cultures. This work provides a proof of concept for the use of Claudin-6 to eliminate residual undifferentiated hPSCs from culture, highlighting a strategy that may increase the safety of hPSC-based cell therapies.
Immunologic and chemical targeting of the tight-junction protein Claudin-6 eliminates tumorigenic human pluripotent stem cells.
Specimen part, Cell lineView Samples
Pluripotent-specific inhibitors (PluriSIns) make a powerful tool for studying the mechanisms that control the survival of human pluripotent stem cells (hPSCs). Here we characterize PluriSIn#2 as a novel selective indirect inhibitor of topoisomerase II alpha (TOP2A). We find that TOP2A is uniquely expressed in undifferentiated hPSCs, and that its inhibition results in their rapid cell death. These findings reveal a dependency of hPSCs on the activity of TOP2A, which can be harnessed for their selective elimination from culture.
Brief reports: Controlling the survival of human pluripotent stem cells by small molecule-based targeting of topoisomerase II alpha.
Specimen part, Cell line, TreatmentView Samples
During early development before gonadal differentiation, sex chromosomes are the main difference between males and females. We examined any genetically driven sex dimorphisms in human pluripotent stem cells focusing on Y chromosome contribution.
Sex-dependent gene expression in human pluripotent stem cells.
Sex, Specimen partView Samples
Human 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 lineView Samples
Three parthenogenetic induced pluripotent stem cell (PgHiPSCs) lines were generated from each of the ovarian teratoma cell lines (two distinct individuals). Two normal iPS cell lines were generated from normal fibroblasts. Three biological replicates of normal embryonic stem cells (H9, HESCs) were perfomed.
Global analysis of parental imprinting in human parthenogenetic induced pluripotent stem cells.
Sex, Cell lineView Samples
Teratoma formation is the gold standard assay for testing the capacity of human stem cells to differentiate into all embryonic germ layers. Although widely used, little effort has been made to transform this qualitative assay into a quantitative one. Using gene expression data from a wide variety of cells, we created a gene scorecard representing tissues from all three germ layers as well as an extraembryonic tissue. A calculated grade using this gene list successfully distinguishes pluripotent stem cell-initiated teratomas from malignant tumors, thereby translating cell potency into a quantitative measure. This new methodology, named TeratoScore, thus assesses the pluripotency of human cells, and is easily performed using an open-source code. The new teratoma database also allowed us to examine the gene expression differences between tumors with a diploid karyotype and those initiated by aneuploid cells. We found that while teratomas originating from aneuploid cells pass the TeratoScore benchmark for pluripotency, they exhibit aberrant gene expression congruent with human chromosomal syndromes (such as Down syndrome). This gene expression signature is significantly different from that of teratomas originating from diploid cells, particularly in central nervous system-specific genes, suggesting aberrant teratomas may be beneficial for in vivo disease modeling. Teratoma formation followed by TeratoScore analysis can rapidly assess cell potency and allows comparison between different pluripotent cell lines.
TeratoScore: Assessing the Differentiation Potential of Human Pluripotent Stem Cells by Quantitative Expression Analysis of Teratomas.
Cell lineView Samples
Two ELK-1 overexpressing cells were generated from CSES7 cell line and compared to WT CSES7.
Human pluripotent stem cells with distinct X inactivation status show molecular and cellular differences controlled by the X-Linked ELK-1 gene.
Sex, Specimen part, Cell line, TreatmentView Samples
Human iPS cells derived from normal and Fragile-X fibroblasts in order to assess the capability of Fragile-X iPS cells to be used as a model for different aspects of Fragile-X syndrome. Microarry analysis used to compare global gene expression between human ES cells, the normal and the mutant iPS cells and the original fibroblasts, to demonstrate that the overall reprogramming process succeeded, and that the FX-iPS cells are fully reprogrammed cells.
Differential modeling of fragile X syndrome by human embryonic stem cells and induced pluripotent stem cells.
Specimen part, Disease, Cell lineView Samples
Three induced pluripotent stem (iPS) cell lines were generated from pancreatic BCD (beta-cell-derived cells). One iPS cell clone was derived from pancreatic non-beta cells. We used microarrays to study the gene expression profiles of beta-iPSCs, and compared the expression of genes in their somatic parental cells and other ES and iPS cells.
Epigenetic memory and preferential lineage-specific differentiation in induced pluripotent stem cells derived from human pancreatic islet beta cells.
Sex, Specimen partView Samples