scholarly journals The Histone Variant MacroH2A Blocks Cellular Reprogramming by Inhibiting Mesenchymal-to-Epithelial Transition

2018 ◽  
Vol 38 (10) ◽  
pp. e00669-17 ◽  
Author(s):  
Maria Pliatska ◽  
Maria Kapasa ◽  
Antonis Kokkalis ◽  
Alexander Polyzos ◽  
Dimitris Thanos

ABSTRACT Transcription factor-induced reprogramming of somatic cells to pluripotency is mediated via profound alterations in the epigenetic landscape. The histone variant macroH2A1 (mH2A1) is a barrier to the cellular reprogramming process. We demonstrate here that mH2A1 blocks reprogramming and contributes to the preservation of cell identity by trapping cells at the very early stages of the process, namely, at the mesenchymal-to-epithelial transition (MET). We provide a comprehensive analysis of the genomic sites occupied by the mH2A1 nucleosomes in human fibroblasts and embryonic stem (ES) cells and how they affect the reprogramming of fibroblasts to pluripotency. We have integrated chromatin immunoprecipitation sequencing (ChIP-seq) data with transcriptome sequencing (RNA-seq) data using cells containing reduced levels of mH2A1 and have inferred mH2A1-centered gene-regulatory networks that support the fibroblast and ES cell fates. We found that the exact positions of mH2A1 nucleosomes in regulatory regions of specific network genes with key regulatory roles guarantee the functional robustness of the regulatory networks. Using the reconstructed networks, we can predict and validate several components and their interactions in the establishment of stable cell types by limiting progression to alternative cell fates.

2014 ◽  
Vol 35 (5) ◽  
pp. 770-777 ◽  
Author(s):  
Sharon Schlesinger ◽  
Stephen P. Goff

Retroviruses have evolved complex transcriptional enhancers and promoters that allow their replication in a wide range of tissue and cell types. Embryonic stem (ES) cells, however, characteristically suppress transcription of proviruses formed after infection by exogenous retroviruses and also of most members of the vast array of endogenous retroviruses in the genome. These cells have unusual profiles of transcribed genes and are poised to make rapid changes in those profiles upon induction of differentiation. Many of the transcription factors in ES cells control both host and retroviral genes coordinately, such that retroviral expression patterns can serve as markers of ES cell pluripotency. This overlap is not coincidental; retrovirus-derived regulatory sequences are often used to control cellular genes important for pluripotency. These sequences specify the temporal control and perhaps “noisy” control of cellular genes that direct proper cell gene expression in primitive cells and their differentiating progeny. The evidence suggests that the viral elements have been domesticated for host needs, reflecting the wide-ranging exploitation of any and all available DNA sequences in assembling regulatory networks.


Author(s):  
Ane Iturbide ◽  
Mayra L. Ruiz Tejeda Segura ◽  
Camille Noll ◽  
Kenji Schorpp ◽  
Ina Rothenaigner ◽  
...  

AbstractTotipotent cells hold enormous potential for regenerative medicine. Thus, the development of cellular models recapitulating totipotent-like features is of paramount importance. Cells resembling the totipotent cells of early embryos arise spontaneously in mouse embryonic stem (ES) cell cultures. Such ‘2-cell-like-cells’ (2CLCs) recapitulate 2-cell-stage features and display expanded cell potential. Here, we used 2CLCs to perform a small-molecule screen to identify new pathways regulating the 2-cell-stage program. We identified retinoids as robust inducers of 2CLCs and the retinoic acid (RA)-signaling pathway as a key component of the regulatory circuitry of totipotent cells in embryos. Using single-cell RNA-seq, we reveal the transcriptional dynamics of 2CLC reprogramming and show that ES cells undergo distinct cellular trajectories in response to RA. Importantly, endogenous RA activity in early embryos is essential for zygotic genome activation and developmental progression. Overall, our data shed light on the gene regulatory networks controlling cellular plasticity and the totipotency program.


2011 ◽  
Vol 2011 ◽  
pp. 1-18 ◽  
Author(s):  
Chad M. Teven ◽  
Xing Liu ◽  
Ning Hu ◽  
Ni Tang ◽  
Stephanie H. Kim ◽  
...  

Stem cells are characterized by their capability to self-renew and terminally differentiate into multiple cell types. Somatic or adult stem cells have a finite self-renewal capacity and are lineage-restricted. The use of adult stem cells for therapeutic purposes has been a topic of recent interest given the ethical considerations associated with embryonic stem (ES) cells. Mesenchymal stem cells (MSCs) are adult stem cells that can differentiate into osteogenic, adipogenic, chondrogenic, or myogenic lineages. Owing to their ease of isolation and unique characteristics, MSCs have been widely regarded as potential candidates for tissue engineering and repair. While various signaling molecules important to MSC differentiation have been identified, our complete understanding of this process is lacking. Recent investigations focused on the role of epigenetic regulation in lineage-specific differentiation of MSCs have shown that unique patterns of DNA methylation and histone modifications play an important role in the induction of MSC differentiation toward specific lineages. Nevertheless, MSC epigenetic profiles reflect a more restricted differentiation potential as compared to ES cells. Here we review the effect of epigenetic modifications on MSC multipotency and differentiation, with a focus on osteogenic and adipogenic differentiation. We also highlight clinical applications of MSC epigenetics and nuclear reprogramming.


2018 ◽  
Vol 20 (1) ◽  
pp. 19 ◽  
Author(s):  
Yadong Wei ◽  
Krishan Chhiba ◽  
Fengrui Zhang ◽  
Xujun Ye ◽  
Lihui Wang ◽  
...  

Sialic acid-binding Ig-like lectin 8 (Siglec-8) is expressed on the surface of human eosinophils, mast cells, and basophils—cells that participate in allergic and other diseases. Ligation of Siglec-8 by specific glycan ligands or antibodies triggers eosinophil death and inhibits mast cell degranulation; consequences that could be leveraged as treatment. However, Siglec-8 is not expressed in murine and most other species, thus limiting preclinical studies in vivo. Based on a ROSA26 knock-in vector, a construct was generated that contains the CAG promoter, a LoxP-floxed-Neo-STOP fragment, and full-length Siglec-8 cDNA. Through homologous recombination, this Siglec-8 construct was targeted into the mouse genome of C57BL/6 embryonic stem (ES) cells, and chimeric mice carrying the ROSA26-Siglec-8 gene were generated. After cross-breeding to mast cell-selective Cre-recombinase transgenic lines (CPA3-Cre, and Mcpt5-Cre), the expression of Siglec-8 in different cell types was determined by RT-PCR and flow cytometry. Peritoneal mast cells (dual FcεRI+ and c-Kit+) showed the strongest levels of surface Siglec-8 expression by multicolor flow cytometry compared to expression levels on tissue-derived mast cells. Siglec-8 was seen on a small percentage of peritoneal basophils, but not other leukocytes from CPA3-Siglec-8 mice. Siglec-8 mRNA and surface protein were also detected on bone marrow-derived mast cells. Transgenic expression of Siglec-8 in mice did not affect endogenous numbers of mast cells when quantified from multiple tissues. Thus, we generated two novel mouse strains, in which human Siglec-8 is selectively expressed on mast cells. These mice may enable the study of Siglec-8 biology in mast cells and its therapeutic targeting in vivo.


2014 ◽  
Vol 369 (1657) ◽  
pp. 20130542 ◽  
Author(s):  
David-Emlyn Parfitt ◽  
Michael M. Shen

To date, many regulatory genes and signalling events coordinating mammalian development from blastocyst to gastrulation stages have been identified by mutational analyses and reverse-genetic approaches, typically on a gene-by-gene basis. More recent studies have applied bioinformatic approaches to generate regulatory network models of gene interactions on a genome-wide scale. Such models have provided insights into the gene networks regulating pluripotency in embryonic and epiblast stem cells, as well as cell-lineage determination in vivo . Here, we review how regulatory networks constructed for different stem cell types relate to corresponding networks in vivo and provide insights into understanding the molecular regulation of the blastocyst–gastrula transition.


Blood ◽  
2006 ◽  
Vol 107 (4) ◽  
pp. 1265-1275 ◽  
Author(s):  
Abby L. Olsen ◽  
David L. Stachura ◽  
Mitchell J. Weiss

Embryonic stem (ES) cells exhibit the remarkable capacity to become virtually any differentiated tissue upon appropriate manipulation in culture, a property that has been beneficial for studies of hematopoiesis. Until recently, the majority of this work used murine ES cells for basic research to elucidate fundamental properties of blood-cell development and establish methods to derive specific mature lineages. Now, the advent of human ES cells sets the stage for more applied pursuits to generate transplantable cells for treating blood disorders. Current efforts are directed toward adapting in vitro hematopoietic differentiation methods developed for murine ES cells to human lines, identifying the key interspecies differences in biologic properties of ES cells, and generating ES cell-derived hematopoietic stem cells that are competent to repopulate adult hosts. The ultimate medical goal is to create patient-specific and generic ES cell lines that can be expanded in vitro, genetically altered, and differentiated into cell types that can be used to treat hematopoietic diseases.


2018 ◽  
Author(s):  
Christopher L. Baker ◽  
Michael Walker ◽  
Seda Arat ◽  
Guruprasad Ananda ◽  
Pavlina Petkova ◽  
...  

ABSTRACTAlthough a variety of writers, readers, and erasers of epigenetic modifications are known, we have little information about the underlying regulatory systems controlling the establishment and maintenance of the epigenetic landscape, which varies greatly among cell types. Here, we have explored how natural genetic variation impacts the epigenome in mice. Studying levels of H3K4me3, a histone modification at sites such as promoters, enhancers, and recombination hotspots, we found tissue-specific trans-regulation of H3K4me3 levels in four highly diverse cell types: male germ cells, embryonic stem (ES) cells, hepatocytes and cardiomyocytes. To identify the genetic loci involved, we measured H3K4me3 levels in male germ cells in a mapping population of 60 BXD recombinant inbred lines, identifying extensive trans-regulation primarily controlled by six major histone quantitative trait loci (hQTL). These chromatin regulatory loci act dominantly to suppress H3K4me3, which at hotspots reduces the likelihood of subsequent DNA double-strand breaks. QTL locations do not correspond with enzyme known to metabolize chromatin features. Instead their locations match clusters of zinc finger genes, making these possible candidates that explain the dominant suppression of H3K4me3. Collectively, these data describe an extensive, tissue-specific set of chromatin regulatory loci that control functionally related chromatin sites.


2017 ◽  
Author(s):  
Scott Ronquist ◽  
Geoff Patterson ◽  
Markus Brown ◽  
Stephen Lindsly ◽  
Haiming Chen ◽  
...  

AbstractThe day we understand the time evolution of subcellular elements at a level of detail comparable to physical systems governed by Newton’s laws of motion seems far away. Even so, quantitative approaches to cellular dynamics add to our understanding of cell biology, providing data-guided frameworks that allow us to develop better predictions about, and methods for, control over specific biological processes and system-wide cell behavior. In this paper, we describe an approach to optimizing the use of transcription factors (TFs) in the context of cellular reprogramming. We construct an approximate model for the natural evolution of a cell cycle synchronized population of human fibroblasts, based on data obtained by sampling the expression of 22,083 genes at several time points along the cell cycle. In order to arrive at a model of moderate complexity, we cluster gene expression based on the division of the genome into topologically associating domains (TADs) and then model the dynamics of the TAD expression levels. Based on this dynamical model and known bioinformatics, such as transcription factor binding sites (TFBS) and functions, we develop a methodology for identifying the top transcription factor candidates for a specific cellular reprogramming task. The approach used is based on a device commonly used in optimal control. Our data-guided methodology identifies a number of transcription factors previously validated for reprogramming and/or natural differentiation. Our findings highlight the immense potential of dynamical models, mathematics, and data-guided methodologies for improving strategies for control over biological processes.Significance StatementReprogramming the human genome toward any desirable state is within reach; application of select transcription factors drives cell types toward different lineages in many settings. We introduce the concept of data-guided control in building a universal algorithm for directly reprogramming any human cell type into any other type. Our algorithm is based on time series genome transcription and architecture data and known regulatory activities of transcription factors, with natural dimension reduction using genome architectural features. Our algorithm predicts known reprogramming factors, top candidates for new settings, and ideal timing for application of transcription factors. This framework can be used to develop strategies for tissue regeneration, cancer cell reprogramming, and control of dynamical systems beyond cell biology.


Development ◽  
1996 ◽  
Vol 122 (8) ◽  
pp. 2339-2348 ◽  
Author(s):  
B. Pain ◽  
M.E. Clark ◽  
M. Shen ◽  
H. Nakazawa ◽  
M. Sakurai ◽  
...  

Petitte, J.N., Clarck, M.E., Verrinder Gibbins, A. M. and R. J. Etches (1990; Development 108, 185–189) demonstrated that chicken early blastoderm contains cells able to contribute to both somatic and germinal tissue when injected into a recipient embryo. However, these cells were neither identified nor maintained in vitro. Here, we show that chicken early blastoderm contains cells characterised as putative avian embryonic stem (ES) cells that can be maintained in vitro for long-term culture. These cells exhibit features similar to those of murine ES cells such as typical morphology, strong reactivity toward specific antibodies, cytokine-dependent extended proliferation and high telomerase activity. These cells also present high capacities to differentiate in vitro into various cell types including cells from ectodermic, mesodermic and endodermic lineages. Production of chimeras after injection of the cultivated cells reinforced the view that our culture system maintains in vitro some avian putative ES cells.


Development ◽  
1991 ◽  
Vol 113 (4) ◽  
pp. 1325-1333 ◽  
Author(s):  
J.R. Mann ◽  
C.L. Stewart

Diploid androgenetic eggs contain two sperm-derived genomes, and only rarely develop to the early somite stage. Also, previous studies have indicated that androgenetic eggs cannot be rescued in aggregation chimeras beyond embryonic stages. Paradoxically, in blastocyst injection chimeras made with androgenetic embryonic stem (ES) cells of the 129/Sv strain, we previously obtained considerable improvement in developmental potential. Although considerable death occurred in utero, overtly normal chimeric fetuses and occasional postnatal chimeras that developed skeletal abnormalities were observed. Consequently, we have re-evaluated the developmental potential of androgenetic aggregation chimeras utilizing androgenetic eggs of the 129/Sv strain, and of the BALB/c and CD-1 strains for comparison. Regardless of strain, androgenetic aggregation chimeras were generally more inviable than previously observed with androgenetic ES cell chimeras, and often the embryoproper was abnormal even when an androgenetic contribution was detected only in the extra-embryonic membranes. This is at least a partial explanation of the greater viability of androgenetic ES cell chimeras, as ES cells do not colonize significantly certain extra-embryonic tissues. Nevertheless, in the 129/Sv strain, occasional development of chimeras to term was obtained, and one chimera that survived postnatally developed identical skeletal abnormalities to those observed previously in androgenetic ES cell chimeras. This result demonstrates that at least one example of paternal imprinting is faithfully conserved in androgenetic ES cells. Also, the postnatal chimerism shows that androgenetic eggs can give rise to terminally differentiated cell types, and are therefore pluripotent. In contrast, only possibly one BALB/c and no CD-1 androgenetic aggregation chimeras developed to term. Therefore, the developmental potential of androgenetic aggregation chimeras is to some extent dependent on mouse strain.


Sign in / Sign up

Export Citation Format

Share Document