Induced pluripotent stem (iPS) cells can be obtained from fibroblasts by expression of Oct4, Sox2, Klf4, and c-Myc. To determine how these factors induce this change in cell identity, we carried out genomewide promoter analysis of their binding in iPS and partially reprogrammed cells. Most targets in iPS cells are shared with ES cells and the factors cooperate to activate the ES-like expression program. In partially reprogrammed cells, genes bound by c-Myc have achieved a more ES-like binding and expression pattern. In contrast, genes that are co-bound by Oct4, Sox2, and Klf4 in ES cells and that encode pluripotency regulators show severe lack of both binding and transcriptional activation. Among the factors, c-Myc has a pivotal effect on the initiation of the ES transcription program, including the repression of fibroblast-specific genes. Our analysis begins to unravel how the four factors function together and suggests a temporal and separable order of their effects during reprogramming.
Role of the murine reprogramming factors in the induction of pluripotency.
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View SamplesThe development of the central nervous system (CNS) depends on the orchestrated generation of neurons and glia from neural stem cells (NSCs). Although NSCs generate both cell types, they are produced sequentially as neurons are born first and glia later. In humans, this timing is extremely protracted and the underlying mechanisms remain unknown. Deriving glial cells such as astrocytes from human pluripotent stem cells requires 3-6 months of differentiation, greatly impeding their use in human disease modeling and regenerative medicine. Here, we report that expression of the transcription factor nuclear factor IA (NFIA) is sufficient to trigger glial competency in highly neurogenic NSCs and enables the derivation of human astrocytes within 10-12 days. NFIA-induced astrocytes are functional and shown to promote synaptogenesis, protect neurons and generate calcium transients. The mechanism of NFIA-induced glial competency involves rapid but reversible chromatin remodeling, demethylation of the GFAP promoter and a striking effect on the cell cycle. NFIA titration and pharmacological studies indicate that acquisition of a glial-compatible G1 length is critical for achieving glial competency. Our results offer mechanistic insights into human glial competency and enable the routine use of astrocytes for studying human development and disease. Overall design: The timecourse consists of 4 timpoints. Day 0 (d0) represents neurogenic LTNSCs, day 3 (d3) represents overexpression of NFIA with doxycycline and cells were harvested in bulk, day 6 (d6) represents cells sorted for CD44 while NFIA is overexpressed, day 9 (d9) represents CD44+ sorted cells replated in culture without the addition of doxycyline to downregulate NFIA and day 12 (d12) represents the same cultures in d9, but with 3 additional days of no doxycycline treatment. Each timepoint has a minimum of 3 biological replicates. Rosette cells (H9 d0) and neurons (Dapt) were profiled as controls where rosettes were one sample and neurons were performed in duplicate.
NFIA is a gliogenic switch enabling rapid derivation of functional human astrocytes from pluripotent stem cells.
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View SamplesExpression profile of dermal fibroblasts reprogrammed to a pluripotent state
Generation of human induced pluripotent stem cells from dermal fibroblasts.
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View SamplesFamilial Dysautonomia is a genetic disease, however patietns with the same genotype present with mild or severe forms of the disease. We used the pluripotent stem cell technology to capture the differences in disease severity in vitro during neurodevelopment as well as during maintanance of the cells, showing developmental and degenerative phenotypes. RNA seq. analysis of the groups confirmed those diffferences. Overall design: Analysis of RNA from PSC-derived neural crest cells from severe FD, mild FD and healthy patients
Capturing the biology of disease severity in a PSC-based model of familial dysautonomia.
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View SamplesWe have generated expression profiles of induced pluripotent stem cells (iPSCs) and iPSC-derived neural crest populations from Familial Dysautonomia patients. These profiles were compared to a normal iPSC line that does not harbor the IKBKAP mutation. Overall design: All cell types were differentiated from patient derived iPSCs. Bulk iPSCs were harvested for RNA and the neural crest populations were sorted on day 18 for p75/HNK1 before RNA isolation.
Capturing the biology of disease severity in a PSC-based model of familial dysautonomia.
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View SamplesComparison of human iPSC lines, ESC and fibroblasts to determine their expression patterns. All early passage female lines profiled expressed XIST RNA which is an indicator of an inactive X chromosome. Genes on the X-chromosome were also analyzed for overall levels of gene expression compared to human fibroblasts.
Female human iPSCs retain an inactive X chromosome.
Specimen part
View SamplesFat tissue was resected during gastric bypass surgery for management of obesity. All subjects had fasted at least 10 hours before surgery. Subjects with malignancies were excluded. No subjects were taking thiazolidinediones or steroids. None had fasting plasma glucose levels over 120 mg/ dl. One half to 10 g of abdominal subcutaneous (external to the fascia superficialis), mesenteric, and greater omental fat were obtained from each subject. The tissue was collected in Hanks balanced salt solution with bicarbonate, penicillin, and gentamicin. Fat tissue was minced and then digested in HBSS containing 1 mg/ml collagenase and 7.5% fetal bovine serum in a 37*C shaking water bath until fragments were no longer visible and the digest had a milky appearance. Digests were filtered and centrifuged at 800xG for 10 min. The digests were treated with an erythrocyte lysis buffer. Cells were plated in 1:1 Dulbeccos modified Eagles medium:Hams F12 that contained 10% fetal bovine serum and antibiotics at a density of 4 x 104 cells/cm2. After 18 hours cultures were trypsinized until 95% of cells were detached (leaving endothelial cells and macrophages behind) and re-plated. Macrophages were rare (less than 5 per 106 cells, as assessed by phase contrast microscopy) in the re-plated cultures, irrespective of fat depot origin. Plating medium was changed every 2 days until confluence. For differentiation, preadipocytes were treated for 30 days with plating medium (without serum) enriched with 100 nM dexamethasone, 500 nM human insulin, 200 pM triiodothyronine, 0.5 *M rosiglitazone, antibiotics, and 540 *M methylisobutylxanthine (removed after 2 days). Higher rosiglitazone and insulin concentrations did not further enhance differentiation. Medium was changed every 2 days. For the final 2 days, differentiation medium was removed and cells were cultured in plating medium without serum. Undifferentiated preadipocytes were maintained in plating medium until confluence, when serum was removed for 2 days. For telomerase-expressing clones, preadipocytes were isolated and when cells had undergone 7 population doublings, they were transduced with a retrovirus containing the plasmid, pBABE-hTERT-Hygro. This vector expresses the human telomerase reverse transcriptase component (hTERT) driven by the Moloney murine leukemia virus long terminal repeat promoter and a hygromycin resistance sequence driven by the SV40 promoter. The 3 abdominal subcutaneous and 3 omental stably transduced, hygromycin-resistant clones capable of achieving confluence fastest were selected from 38 subcutaneous and 42 omental clones. Telomerase activity in these clones was verified using a PCR-based telomere repeat amplification protocol. RNA was isolated from preadipocytes by the Trizol method. RNA samples were labeled using the standard one-cycle Affymetrix GeneChip Eukaryotic Target Labeling Assay for Expression Analysis. Samples were hybridized for 16 hours at 45 C and 60 rpm, washed and stained according to the standard Affymetrix Antibody Amplification for Eukaryotic Targets protocol, and scanned at 488 nm. Images were quantified and linearly scaled using Affymetrix GeneChip Operating Software 1.1 using default analysis settings.
Identification of depot-specific human fat cell progenitors through distinct expression profiles and developmental gene patterns.
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View SamplesThis dataset includes both whole transcriptome (WT) and mRNA-seq data for interferon-treated mouse samples. This is part of a larger study (GSE52405), where these interferon datasets were used as validation. Overall design: 6-week-old C57BL/6J mice were treated with 10,000 U of recombinant interferon (Universal Type I IFN, Recombinant Human IFN-alpha A/D [BglII], R&D Systems) dissolved in endotoxin-free phosphate-buffered saline (EF-PBS), or with EF-PBS alone. For this study, the mice at 12 hours post-treatment were used.
Annotation of long non-coding RNAs expressed in collaborative cross founder mice in response to respiratory virus infection reveals a new class of interferon-stimulated transcripts.
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View SamplesT-cell acute lymphoblastic leukemia (T-ALL) is mostly characterized by specific chromosomal abnormalities, some occurring in a mutually exclusive manner possibly delineating specific T-ALL subgroups. One subgroup, including MLL-rearranged, CALM-AF10 or inv(7)(p15q34) cases, is characterized by elevated expression of HOXA genes. Using a gene expression based clustering analysis of 67 T-ALL cases with recurrent molecular genetic abnormalities and 25 samples lacking apparent aberrations, we identified 5 new cases with elevated HOXA levels. Using array-CGH, a cryptic and recurrent deletion, del(9)(q34.11q34.13), was exclusively identified in 3 of these 5 cases. This deletion results in a conserved SET-NUP214 fusion product, that was also identified in the T-ALL cell line LOUCY. SET-NUP214 binds in the promoter regions of specific HOXA genes, where it may interact with CRM1 and DOT1L leading to the transcriptional activation of HOXA genes. Targeted inhibition of SET-NUP214 by siRNA abolished expression of HOXA genes, inhibited proliferation and induced differentiation in LOUCY but not in other T-ALL lines. We conclude that SET-NUP214 may contribute to the pathogenesis of T-ALL by enforcing T-cell differentiation arrest.
The recurrent SET-NUP214 fusion as a new HOXA activation mechanism in pediatric T-cell acute lymphoblastic leukemia.
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View SamplesUnderstanding gene expression profile and transcriptional regulation of healthy adult human hepatocytes
Differentiation in stem/progenitor cells along fetal or adult hepatic stages requires transcriptional regulators independently of oscillations in microRNA expression.
Specimen part, Time
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