It has been postulated that during human fetal development all cells of the lung epithelium derive from an embryonic endodermal NKX2-1+ precursor, however, this hypothesis has not been formally tested due to an inability to purify or track this theorized cell for detailed characterization. Here we engineer and developmentally differentiate NKX2-1GFP reporter pluripotent stem cells (PSCs) in vitro to generate and isolate a human primordial lung progenitor that expresses NKX2-1 but is initially devoid of markers of differentiated lung lineages. As these progenitors move through the earliest moments of lung lineage specification from definitive endoderm they can be imaged in real time or isolated for time-series global transcriptomic profiling. We performed microarray analysis of 5 timepoints of human iPSC to lung directed differentiation compared to week 21 human fetal lung and Neural NKX2-1+ cell controls. These profiles indicate that evolutionarily conserved, stage-dependent developmental gene signatures are expressed in primordial human lung progenitors.
Efficient Derivation of Functional Human Airway Epithelium from Pluripotent Stem Cells via Temporal Regulation of Wnt Signaling.
Time
View SamplesThe Grainyhead family of transcription factors controls morphogenesis and differentiation of epithelial cell layers in multicellular organisms by regulating cell junction- and proliferation-related genes. Grainyhead-like 2 (Grhl2) is expressed in developing mouse lung epithelium and is required for normal lung organogenesis. The specific epithelial cells expressing Grhl2 and the genes regulated by Grhl2 in normal lungs are mostly unknown. In these studies, we identified the NK2 homeobox 1 transcription factor (Nkx2-1) as a direct transcriptional target of Grhl2. By binding and transcriptional assays, and by confocal microscopy we showed that these two transcription factors form a positive feed-back loop in vivo and in cell lines, and are co-expressed in lung bronchiolar and alveolar type II cells. The morphological changes observed in flattening lung alveolar type II cells in culture are associated with down-regulation of Grhl2 and Nkx2-1. Reduction of Grhl2 in lung epithelial cell lines results in lower expression levels of Nkx2-1 and of known Grhl2 target genes. By microarray analysis we identified that in addition to Cadherin1 and Claudin4, Grhl2 regulates other cell interaction genes such as semaphorins and their receptors, which also play a functional role in developing lung epithelium. Impaired collective cell migration observed in Grhl2 knockdown cell monolayers is associated with reduced expression of these genes and may contribute to the altered epithelial phenotype reported in Grhl2 mutant mice. Thus, Grhl2 functions at the nexus of a novel regulatory network, connecting lung epithelial cell identity, migration and cell-cell interactions.
The transcription factors Grainyhead-like 2 and NK2-homeobox 1 form a regulatory loop that coordinates lung epithelial cell morphogenesis and differentiation.
Cell line
View SamplesThe concept of tumor stem cells (TSCs) provides a new paradigm for understanding tumor biology, although it remains unclear whether TSCs will prove to be a more robust model than traditional cancer cell lines. We demonstrate marked phenotypic and genotypic differences between primary human tumor-derived TSCs and their matched glioma cell lines. TSCs derived directly from primary glioblastomas harbor extensive similarities to normal NSC and recapitulate the genotype, gene expression patterns and in vivo biology of human glioblastomas. By contrast, the matched, traditionally grown tumor cell lines do not secondary to in vitro genomic alterations. These findings suggest that TSCs may be a more reliable model than many commonly utilized cancer cell lines for understanding the biology of primary human tumors. Analysis of gene expression data is described in Lee et al., Cancer Cell, 2006.
Tumor stem cells derived from glioblastomas cultured in bFGF and EGF more closely mirror the phenotype and genotype of primary tumors than do serum-cultured cell lines.
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View SamplesThe directed differentiation of induced pluripotent stem (iPS) and embryonic stem (ES) cells into definitive endoderm (DE) would allow the derivation of otherwise inaccessible progenitors for endodermal tissues. However, a global comparison of the relative equivalency of DE derived from iPS and ES populations has not been performed. Recent reports of molecular differences between iPS and ES cells have raised uncertainty as to whether iPS cells could generate autologous endodermal lineages in vitro. Here, we have shown that both mouse iPS and parental ES cells exhibited highly similar in vitro capacity to undergo directed differentiation into DE progenitors. With few exceptions, both cell types displayed similar surges in gene expression of specific master transcriptional regulators and global transcriptomes that define the developmental milestones of DE differentiation. Microarray analysis showed considerable overlap between the genetic programs of DE derived from ES/iPS cells in vitro and authentic DE from mouse embryos in vivo. Intriguingly, iPS cells exhibited aberrant silencing of imprinted genes known to participate in endoderm differentiation, yet retained a robust ability to differentiate into DE. Our results show that, despite some molecular differences, iPS cells can be efficiently differentiated into DE precursors, reinforcing their potential for development of cell-based therapies for diseased endodermal-derived tissues.
Mouse ES and iPS cells can form similar definitive endoderm despite differences in imprinted genes.
Specimen part
View SamplesEndodermal progenitor cells (EP cells) are derived from human embryonic stem cell(ESC)-derived definitive endoderm (DE) cells. EP cells are cultured in high BMP media and DE cells are in high Activin media. Both cells can be further differentiated to liver, pancreas, etc.
Self-renewing endodermal progenitor lines generated from human pluripotent stem cells.
Specimen part
View SamplesThe in vitro directed differentiation of pluripotent stem cells (PSCs) through stimulation of developmental signaling pathways can generate mature somatic cell types for basic laboratory studies or regenerative therapies.
Pluripotent stem cell differentiation reveals distinct developmental pathways regulating lung- versus thyroid-lineage specification.
Treatment
View SamplesGliomas are mostly incurable secondary to their diffuse infiltrative nature. Thus, specific therapeutic targeting of invasive glioma cells is an attractive concept. As cells exit the tumor mass and infiltrate brain parenchyma, they closely interact with a changing micro-environmental landscape that sustains tumor cell invasion.
Identification of molecular pathways facilitating glioma cell invasion in situ.
Specimen part
View SamplesTwo populations of Nkx2-1+ progenitors in the developing foregut endoderm give rise to the entire post-natal lung and thyroid epithelium, but little is known about these cells, as they are difficult to isolate in a pure form. We demonstrate here the purification and directed differentiation of primordial lung and thyroid progenitors derived from mouse embryonic stem cells (ESCs). Inhibition of TGF and BMP signaling, followed by combinatorial stimulation of BMP and FGF signaling can specify these cells efficiently from definitive endodermal precursors. When derived using Nkx2-1GFP knock-in reporter ESCs, these progenitors can be purified for expansion in culture and have a transcriptome that overlaps with developing lung epithelium. Upon induction, they can express a broad repertoire of markers indicative of lung and thyroid lineages and can recellularize a 3D lung tissue scaffold. Thus, we have derived a pure population of progenitors able to recapitulate the developmental milestones of lung/thyroid development.
Efficient derivation of purified lung and thyroid progenitors from embryonic stem cells.
Specimen part
View SamplesInduced pluripotent stem cells hold great promise for modeling human hematopoietic diseases. However, intrinsic variability in the capacities of different iPSC lines for hematopoietic development complicates comparative studies and is currently unexplained.
Clonal genetic and hematopoietic heterogeneity among human-induced pluripotent stem cell lines.
Specimen part, Cell line
View SamplesWe used laser capture microdissection to isolate both microvascular endothelial cells and neurons from post mortem brain tissue from patients with schizophrenia and bipolar disorder and healthy controls. RNA was isolated from these cell populations, amplified, and analysed using Affymetrix HG133plus2.0 GeneChips. In the first instance, we used the dataset to compare the neuronal and endothelial data, in order to demonstrate that the predicted differences between cell types could be detected using this methodology.
The cerebral microvasculature in schizophrenia: a laser capture microdissection study.
Specimen part
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