Concerted efforts over past decades have established a thorough understanding of the canonical somatic DNA methylation landscape as well as its systematic misregulation across most human cancers. However, the underlying mechanism that directs this genome-scale transformation remains elusive, with no clear model for its acquisition or understanding of its potential developmental utility. Here we present base pair resolution analysis of global remethylation from the hypomethylated state of the preimplantation embryo into the early epiblast and extraembryonic ectoderm. We show that these two states acquire highly divergent genomic distributions: while the proximal epiblast establishes a canonical CpG-density dependent pattern found in somatic cells, the extraembryonic epigenome becomes substantially more mosaic. Moreover, this alternate pattern includes specific de novo methylation of hundreds of CpG island promoter containing genes that function in early embryonic development and are orthologously methylated across an extensive cohort of human cancers. From these data, we propose a model where the evolutionary innovation of extraembryonic tissues in eutherian mammals required cooption of DNA methylation-based suppression as an alternate pathway to the embryonically utilized Polycomb group proteins, which otherwise coordinate germ layer formation in response to extraembryonic cues at the onset of gastrulation. Moreover, we establish that this decision is made deterministically downstream of the promiscuously utilized, and frequently oncogenic, FGF signaling pathway and utilizes a novel combination of epigenetic cofactors. Recruitment of this silencing mechanism to developmental genes during cancer therefore reflects the misappropriation of an innate regulatory pathway that may be spontaneously sampled as an alternate epigenetic landscape within somatic cells. Overall design: Comparison of gene expression patterns in Extraembryonic Ectoderm and cancer
Epigenetic restriction of extraembryonic lineages mirrors the somatic transition to cancer.
Treatment, Subject
View SamplesSingle-cell expression profiling by RNA-Seq promises to exploit cell-to-cell variation in gene expression to reveal regulatory circuitry governing cell differentiation and other biological processes. Here, we describe Monocle, a novel unsupervised algorithm for ordering cells by progress through differentiation that dramatically increases temporal resolution of expression measurements. This reordering unmasks switch-like changes in expression of key regulatory factors, reveals sequentially organized waves of gene regulation, and exposes regulators of cell differentiation. A functional screen confirms that a number of these regulators dramatically alter the efficiency of myoblast differentiation, demonstrating that single-cell expression analysis with Monocle can uncover new regulators even in well-studied systems. Overall design: We selected primary human myoblasts as a model system of cell differentiation to investigate whether ordering cells by progress revealed new regulators of the process. We sequenced RNA-Seq libraries from each of several hundred cells taken over a time-course of serum-induced differentiation. Please note that this dataset is a single-cell RNA-Seq data set, and each cell comes from a capture plate. Thus, each well of the plate was scored and flagged with several QC criteria prior to library construction, which are provided as sample characteristics; CONTROL indicates that this library is a off-chip tube control library constructed from RNA of approximately 250 cells and ''DEBRIS'' indicates that the well contained visible debris (and may or may not include a cell). Libraries marked DEBRIS thus cannot be confirmed to come from a single cell.
The dynamics and regulators of cell fate decisions are revealed by pseudotemporal ordering of single cells.
No sample metadata fields
View SamplesHere we propose the direct conversion of human somatic cells into naive induced pluripotent cells (niPSC). Dataset: 7 expanded niPSC lines (4 from BJ cells, 1 from HFF-1, 1 from WI38, 1from IMR90), 1 freshly-isolated primary colonies of niPSC from BJ, 1 established naive embryonic line H9, 1 primed induced pluripotent cell line (from BJ), 1 sample of BJ fibroblasts, 1 sample of WI38 fibroblasts, 1 sample IMR90 fibroblasts.
Direct generation of human naive induced pluripotent stem cells from somatic cells in microfluidics.
No sample metadata fields
View SamplesMaddalena et al. showed that the limited DNA transfer capacity (~4.7kb) of adeno associated viral (AAV) vectors can be expanded up to 14kb with triple AAV vectors for the efficient expression of the therapeutic CDH23 (10.1kb) and ALMS1 (12.5kb) genes. Overall design: cells infected with triple AAV vectors carrying 2 different transgenes in 3 biological replicates; RNA extracted from WT cells was used as control .
Triple Vectors Expand AAV Transfer Capacity in the Retina.
Cell line, Subject
View SamplesWe report that combining NGN2 programming with SMAD and WNT inhibition generates patterned induced neurons (hpiNs).Transcriptional analyses showed that hpiN cultures contained cells along a developmental continuumranging from poorly differentiated neuronal progenitors to well-differentiated, excitatory glutamatergic neurons. The most differentiated neurons could be identified using a CAMK2A::GFP reporter gene. Overall design: RNA sequencing analysis (population and single cell) over hpiNs differentiation time (D0 through D49 after induction). Two independent iPS lines, 9 time points, three replicates each.
Combining NGN2 Programming with Developmental Patterning Generates Human Excitatory Neurons with NMDAR-Mediated Synaptic Transmission.
Specimen part, Disease, Cell line, Subject, Time
View SamplesInduced pluripotency is a promising avenue for disease modeling and therapy, but the molecular principles underlying this process, particularly in human cells, remain poorly understood due to donor-to-donor variability and intercellular heterogeneity. Here we constructed and characterized a clonal, inducible human reprogramming system that provides a reliable source of cells at any stage of the process. This system enabled integrative transcriptional and epigenomic analysis across the human reprogramming timeline at high resolution. We observed distinct waves of gene network activation, including the ordered re-activation of broad developmental regulators followed by early embryonic patterning genes and culminating in the emergence of a signature reminiscent of pre-implantation stages. Moreover, complementary functional analyses allowed us to identify and validate novel regulators of the reprogramming process. Altogether, this study sheds light on the molecular underpinnings of induced pluripotency in human cells and provides a robust cell platform for further studies. Overall design: mRNA sequencing of primary and secondary fibroblasts with reference BJ (supplementary file fibroblasts), reprogramming intermendiates from untreated hiF-T reprogramming (supplementary file reprogramming), or selective time points upon LSD1 inhibitor treatment (supplementary file LSD1i). RNA samples used for mRNA sequencing are the same used for smallRNA sequencing.
Integrative Analyses of Human Reprogramming Reveal Dynamic Nature of Induced Pluripotency.
No sample metadata fields
View SamplesInduced pluripotency is a promising avenue for disease modeling and therapy, but the molecular principles underlying this process, particularly in human cells, remain poorly understood due to donor-to-donor variability and intercellular heterogeneity. Here we constructed and characterized a clonal, inducible human reprogramming system that provides a reliable source of cells at any stage of the process. This system enabled integrative transcriptional and epigenomic analysis across the human reprogramming timeline at high resolution. We observed distinct waves of gene network activation, including the ordered re-activation of broad developmental regulators followed by early embryonic patterning genes and culminating in the emergence of a signature reminiscent of pre-implantation stages. Moreover, complementary functional analyses allowed us to identify and validate novel regulators of the reprogramming process. Altogether, this study sheds light on the molecular underpinnings of induced pluripotency in human cells and provides a robust cell platform for further studies. Overall design: single cell RNA-seq profiles from 52 unfractionated hiF-T cells after 10 days of reprogramming
Integrative Analyses of Human Reprogramming Reveal Dynamic Nature of Induced Pluripotency.
No sample metadata fields
View SamplesN6-methyladenosine (m6A) is a common modification of mRNA, with potential roles in fine-tuning the RNA life cycle, but little is known about the pathways regulating this process and its physiological role. Here, we used mass-spectrometry to identify a dense network of proteins physically interacting with METTL3, a core component of the methyltransferase complex, and show that two of them, WTAP and KIAA1429, are required for methylation. Combining high resolution m6A-Seq with knockdown of WTAP allowed us to define accurate maps, at near single-nucleotide resolution, of sites of mRNA methylation across four dynamic programs in human and mouse, including development, differentiation, reprogramming and immune response. Internal WTAP-dependent methylation sites were largely static across the different surveyed conditions and present in the majority of mRNAs. However, methylations were found at much lower levels within highly expressed mRNAs, and methylation is inversely correlated with mRNA stability, consistent with a role in establishing an overall basal, cell-type invariant, distribution of degradation rates. In addition, we identify thousands of WTAP-independent methylation sites at transcription initiation sites, forming part of the mRNA cap structure. We show that the methylations occur at the first transcribed nucleotide, and find that thousands of transcripts are present in different isoforms differing in the methylation state of the first transcribed nucleotide, a previously unappreciated complexity of the transcriptome. Together, our data sheds new light on the proteomic and transcriptional underpinnings of this epitranscriptomic modification in mammals. Overall design: Examination of m6A methylation in human Hek293 and A549 cell lines, in human embryonic stem cells (ESCs) undergoing differentiation to neural progenitor cells (NPCs), in OKMS inducible fibroblasts reprogrammed into iPSC, and upon knockdown of factors using siRNAs or shRNAs.
Perturbation of m6A writers reveals two distinct classes of mRNA methylation at internal and 5' sites.
No sample metadata fields
View SamplesN6-methyladenosine (m6A) is a common modification of mRNA, with potential roles in fine-tuning the RNA life cycle, but little is known about the pathways regulating this process and its physiological role. Here, we used mass-spectrometry to identify a dense network of proteins physically interacting with METTL3, a core component of the methyltransferase complex, and show that two of them, WTAP and KIAA1429, are required for methylation. Combining high resolution m6A-Seq with knockdown of WTAP allowed us to define accurate maps, at near single-nucleotide resolution, of sites of mRNA methylation across four dynamic programs in human and mouse, including development, differentiation, reprogramming and immune response. Internal WTAP-dependent methylation sites were largely static across the different surveyed conditions and present in the majority of mRNAs. However, methylations were found at much lower levels within highly expressed mRNAs, and methylation is inversely correlated with mRNA stability, consistent with a role in establishing an overall basal, cell-type invariant, distribution of degradation rates. In addition, we identify thousands of WTAP-independent methylation sites at transcription initiation sites, forming part of the mRNA cap structure. We show that the methylations occur at the first transcribed nucleotide, and find that thousands of transcripts are present in different isoforms differing in the methylation state of the first transcribed nucleotide, a previously unappreciated complexity of the transcriptome. Together, our data sheds new light on the proteomic and transcriptional underpinnings of this epitranscriptomic modification in mammals. Overall design: Examination of m6A methylation across different knockdowns using shRNAs in mouse embryonic fibroblasts, in embyronic and adult brains, and in dendritic cell stimulated with LPS.
Perturbation of m6A writers reveals two distinct classes of mRNA methylation at internal and 5' sites.
No sample metadata fields
View SamplesWhile gene expression dynamics have been extensively catalogued during hematopoietic differentiation in the adult, less is known about transcriptome diversity of human hematopoietic stem cells (HSCs) during development. To characterize transcriptional and post-transcriptional changes in HSCs during development, we leveraged high-throughput genomic approaches to profile miRNAs, lincRNAs, and mRNAs. Our findings indicate that HSCs manifest distinct alternative splicing patterns in key hematopoietic regulators. Detailed analysis of the splicing dynamics and function of one such regulator, HMGA2, identified an alternative isoform that escapes miRNA-mediated targeting. We further identified the splicing kinase CLK3 that, by regulating HMGA2 splicing, preserves HMGA2 function in the setting of an increase in let-7 miRNA levels, delineating how CLK3 and HMGA2 form a functional axis that influences HSC properties during development. Collectively, our study highlights molecular mechanisms by which alternative splicing and miRNA-mediated post-transcriptional regulation impact the molecular identity and stage-specific developmental features of human HSCs. Overall design: RNA-seq of HPC-5F cells transduced with a control (CTRL), HMGA2-L (LONG), HMGA2-S (SHORT) or CLK3 ORF lentiviral over-expression vectors.
A CLK3-HMGA2 Alternative Splicing Axis Impacts Human Hematopoietic Stem Cell Molecular Identity throughout Development.
Specimen part, Subject
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