scholarly journals Chd1 regulates repair of promoter-proximal DNA breaks to sustain hypertranscription in embryonic stem cells

2019 ◽  
Author(s):  
Aydan Bulut-Karslioglu ◽  
Hu Jin ◽  
Marcela Guzman-Ayala ◽  
Andrew JK Williamson ◽  
Miroslav Hejna ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cancer Biology ◽  
Es Cells ◽  
Embryonic Stem ◽  
Dependent Manner ◽  
Dna Breaks ◽  
Pol I ◽  
Stem And Progenitor Cells

AbstractStem and progenitor cells undergo a global elevation of nascent transcription, or hypertranscription, during key developmental transitions involving rapid cell proliferation. The chromatin remodeler Chd1 binds to genes transcribed by RNA Polymerase (Pol) I and II and is required for hypertranscription in embryonic stem (ES) cells in vitro and the early post-implantation epiblast in vivo. Biochemically, Chd1 has been shown to facilitate transcription at least in part by removing nucleosomal barriers to elongation, but its mechanism of action in stem cells remains poorly understood. Here we report a novel role for Chd1 in the repair of promoter-proximal endogenous double-stranded DNA breaks (DSBs) in ES cells. An unbiased proteomics approach revealed that Chd1 interacts with several DNA repair factors including Atm, Parp1, Kap1 and Topoisomerase 2β. We show that wild-type ES cells display high levels of phosphorylated H2A.X and Kap1 at chromatin, notably at rDNA in the nucleolus, in a Chd1-dependent manner. Loss of Chd1 leads to an extensive accumulation of DSBs at Chd1-bound Pol II-transcribed genes and rDNA. Genes prone to DNA breaks in Chd1 KO ES cells tend to be longer genes with GC-rich promoters, a more labile nucleosomal structure and roles in chromatin regulation, transcription and signaling. These results reveal a vulnerability of hypertranscribing stem cells to endogenous DNA breaks, with important implications for developmental and cancer biology.

scholarly journals Chd1 protects genome integrity at promoters to sustain hypertranscription in embryonic stem cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aydan Bulut-Karslioglu ◽  
Hu Jin ◽  
Yun-Kyo Kim ◽  
Brandon Cho ◽  
Marcela Guzman-Ayala ◽  
...  
Keyword(s):  
Stem Cells ◽  
Cancer Biology ◽  
Es Cells ◽  
Embryonic Stem ◽  
Genome Integrity ◽  
Dna Breaks ◽  
Promoter Regions ◽  
Rdna Genes ◽  
Stem And Progenitor Cells ◽  
Nucleosomal Structure

AbstractStem and progenitor cells undergo a global elevation of nascent transcription, or hypertranscription, during key developmental transitions involving rapid cell proliferation. The chromatin remodeler Chd1 mediates hypertranscription in pluripotent cells but its mechanism of action remains poorly understood. Here we report a novel role for Chd1 in protecting genome integrity at promoter regions by preventing DNA double-stranded break (DSB) accumulation in ES cells. Chd1 interacts with several DNA repair factors including Atm, Parp1, Kap1 and Topoisomerase 2β and its absence leads to an accumulation of DSBs at Chd1-bound Pol II-transcribed genes and rDNA. Genes prone to DNA breaks in Chd1 KO ES cells are longer genes with GC-rich promoters, a more labile nucleosomal structure and roles in chromatin regulation, transcription and signaling. These results reveal a vulnerability of hypertranscribing stem cells to accumulation of endogenous DNA breaks, with important implications for developmental and cancer biology.

230 GENERATION OF PUTATIVE RABBIT EMBRYONIC STEM CELLS

2007 ◽  
Vol 19 (1) ◽  
pp. 231
Author(s):  
S. Wang ◽  
X. Tang ◽  
Y. Niu ◽  
H. Chen ◽  
T. Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
High Speed ◽  
Es Cells ◽  
Research Work ◽  
Embryonic Stem ◽  
Morphological Characteristics ◽  
Mouse Escs

The rabbit, as a laboratory animal model, has several advantages in the study of human physiological disorders. In this study, stable putative pluripotent rabbit embryonic stem cells (rESCs) were derived from in vivo-fertilized and in vitro-cultured blastocysts. The rabbit ICMs were obtained by 0.05% trypsin–0.008% EDTA treatment and mechanical separation; the ES-like cell colonies seen several days later. ICM-derived outgrowths which were treated with 5 mg/mL-1 dispase, followed by 0.05% trypsin–0.008% EDTA, were mechanically disaggregated into small clumps and reseeded on MEFs. The putative ES cell lines maintained expression of pluripotent cells markers and normal XY karyotype for long periods of culture (>1 month). The putative rESCs expressed alkaline phosphatase, transcription factor Oct-4, stage-specific embryonic antigens (SSEA-1, SSEA-3, and SSEA-4), and tumor-related antigens (TRA-1-60 and TRA-1-81). The morphological characteristics of the putative ESCs are closer to those of human ESCs; their high speed of proliferation, however, is closer to that of mouse ESCs. Putative rabbit ESCs were induced to differentiate into many cell types including trophoblast cells, similar to primate ESCs, in vitro, and formed teratomas with derivatives of the 3 major germ layers in vivo when injected into SCID mice. Using RT-PCR measurement, but with some differences in ligands and inhibitors, and comparing with human and mouse ESCs, the putative rabbit ESCs expressed similar genes related to pluripotency (Oct-4, Nanog, SOX2, and UTF-1) and similar genes of FGF, WNT, and TGF signaling pathways related to the proliferation and self-renewal. Our further research work showed that TGF beta and FGF pathways cooperate to maintain pluripotency of rabbit ESCs similar to those of human ES cells.

scholarly journals Human embryonic stem cells for brain repair?

2007 ◽  
Vol 363 (1489) ◽  
pp. 87-99 ◽  
Author(s):  
Su-Chun Zhang ◽  
Xue-Jun Li ◽  
M Austin Johnson ◽  
Matthew T Pankratz
Keyword(s):  
Stem Cells ◽  
Motor Neurons ◽  
Es Cells ◽  
Embryonic Stem ◽  
Dopamine Neurons ◽  
Neural Cells ◽  
Es Cell ◽  
Human Es Cells

Cell therapy has been perceived as the main or ultimate goal of human embryonic stem (ES) cell research. Where are we now and how are we going to get there? There has been rapid success in devising in vitro protocols for differentiating human ES cells to neuroepithelial cells. Progress has also been made to guide these neural precursors further to more specialized neural cells such as spinal motor neurons and dopamine-producing neurons. However, some of the in vitro produced neuronal types such as dopamine neurons do not possess all the phenotypes of their in vivo counterparts, which may contribute to the limited success of these cells in repairing injured or diseased brain and spinal cord in animal models. Hence, efficient generation of neural subtypes with correct phenotypes remains a challenge, although major hurdles still lie ahead in applying the human ES cell-derived neural cells clinically. We propose that careful studies on neural differentiation from human ES cells may provide more immediate answers to clinically relevant problems, such as drug discovery, mechanisms of disease and stimulation of endogenous stem cells.

scholarly journals Human Hematopoietic Stem Cells Can Survive In Vitro for Several Months

2009 ◽  
Vol 2009 ◽  
pp. 1-7 ◽  
Author(s):  
Taro Ishigaki ◽  
Kazuhiro Sudo ◽  
Takashi Hiroyama ◽  
Kenichi Miharada ◽  
Haruhiko Ninomiya ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Cultured Cells ◽  
Es Cells ◽  
Embryonic Stem ◽  
Hematopoietic Stem ◽  
Immunodeficient Mice ◽  
Cell Sample

We previously reported that long-lasting in vitro hematopoiesis could be achieved using the cells differentiated from primate embryonic stem (ES) cells. Thus, we speculated that hematopoietic stem cells differentiated from ES cells could sustain long-lasting in vitro hematopoiesis. To test this hypothesis, we investigated whether human hematopoietic stem cells could similarly sustain long-lasting in vitro hematopoiesis in the same culture system. Although the results varied between experiments, presumably due to differences in the quality of each hematopoietic stem cell sample, long-lasting in vitro hematopoiesis was observed to last up to nine months. Furthermore, an in vivo analysis in which cultured cells were transplanted into immunodeficient mice indicated that even after several months of culture, hematopoietic stem cells were still present in the cultured cells. To the best of our knowledge, this is the first report to show that human hematopoietic stem cells can survive in vitro for several months.

ES cells have only a limited lymphopoietic potential after adoptive transfer into mouse recipients

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1343-1351
Author(s):  
A.M. Muller ◽  
E.A. Dzierzak
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Es Cells ◽  
Embryonic Stem ◽  
Mouse Development ◽  
Hematopoietic Stem ◽  
Developmental Potential

While hematopoietic stem cells from adult and fetal stages of murine development are capable of long term reconstitution of all mature blood lineages in vivo, embryonic hematopoietic stem cell repopulation in vivo has proved difficult. It is thought that there are many fewer hematopoietic stem cells in the embryo than in the fetal/adult stages of mouse development and that these cells possess a different developmental potential. One source of such cells are embryonic stem (ES) cells which can differentiate into most mature blood lineages in vitro. We have therefore used transplantation of differentiated ES cells to assess the hematopoietic potential of embryonic hematopoietic cells in vivo. We demonstrate here that precursors obtained from in vitro cultures of normal ES cells can contribute only to restricted and limited hematopoiesis in a mouse without leading to tumour formation. Repopulation occurs for greater than 6.5 months at levels ranging from 0.1% to 6% in B and T cell lineages in peripheral blood. In contrast to in vitro colony data demonstrating the myeloid lineage developmental potential of ES cells, no donor-derived myeloid repopulation was observed in CFU-S assays and no macrophage and mast cells were found in long term repopulated recipients. Thus, the hematopoietic potential of ES cells in vivo is limited to low levels of repopulation and is restricted to the lymphoid lineage.

Effect of Arsenic Trioxide on E14 Murine Embryonic Stem Cells In Vitro.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4409-4409
Author(s):  
Barbara Graham-Evans ◽  
Hal Broxmeyer
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Flow Cytometry ◽  
Es Cells ◽  
Embryonic Stem ◽  
Time Dependent ◽  
Dependent Manner ◽  
Murine Embryonic Stem Cells ◽  
Cell Cycle Status

Abstract The ability of pluripotent murine embryonic stem (muES) cells to differentiate into all cell types makes them a very promising tool for cell therapy. The understanding of the molecular mechanisms underlying the growth and differentiation of the ES cells is a pre-requisite for selecting adequately the cell conditions which will be accessible for future use of ES cells in treating hematological malignancies. Pharmacological agents such as arsenic trioxide (As2O3) have shown to be an effective anticancer agent for acute promyelocytic leukemia but its effect on murine embryonic stem cells prior to differentiation and subsequent target organ toxicity is yet to be determined. This study was done to gain insight into the biological effects of As2O3 on muES cell line, E14, with respect to differentiation, proliferation, cytotoxicity and cell cycle status in vitro. MuEs cells were cultured in complete DMEM in the presence of LIF on gelatin coated plates for 24 hours prior to the addition of varying concentrations of As2O3 (0, 0.5,1, 5, and 10 μmol/L, respectively), and the cells were incubated for an additional 48 hours. The differentiation potential of As2O3 was determined by measuring Oct-4 levels by flow cytometry. Proliferation was measured by trypan blue exclusion. Cytotoxicity of As2O3 was determined by MTT assay. Cell cycle status was measured by Propidium Iodide using flow cytometry. Our results demonstrated that As2O3 at different concentrations did not induce differentiation. However, the proliferation of muES cells treated with As2O3 was inhibited in a concentration and time dependent manner. The cell-killing rate of As2O3 on muES cells was both dose and time dependent with an inhibitory concentration (IC50) of ~ 5±0.2 μM and ~3.75±0.7 μM at 24 and 48 hours respectively. Propidium iodide DNA staining revealed that after 48 hour incubation with arsenic, cells in S phase remained relatively constant (~62–67%) at low doses of As2O3 but this decreased by half (33%) at a high dose of 10uM As2O3. The percent of cells in the G2 phase of the cell cycle increased to 41±9% in 10μM treated cells compared to 6±3% in control. In conclusion, As2O3 does not induce the differentiation of muES cells into different lineages, but does inhibit growth and alter the cell cycle kinetics of these cells in a dose dependent manner.

Brachyury - a gene affecting mouse gastrulation and early organogenesis

Development ◽  
1992 ◽  
Vol 116 (Supplement) ◽  
pp. 157-165 ◽  
Author(s):  
R. S. P. Beddington ◽  
P. Rashbass ◽  
V. Wilson
Keyword(s):  
Es Cells ◽  
Embryonic Stem ◽  
Primitive Streak ◽  
Coat Colour ◽  
Es Cell ◽  
Wild Type ◽  
Mesoderm Cell ◽  
Rostrocaudal Axis

Mouse embryos that are homozygous for the Brachyury (T) deletion die at mid-gestation. They have prominent defects in the notochord, the allantois and the primitive streak. Expression of the T gene commences at the onset of gastrulation and is restricted to the primitive streak, mesoderm emerging from the streak, the head process and the notochord. Genetic evidence has suggested that there may be an increasing demand for T gene function along the rostrocaudal axis. Experiments reported here indicate that this may not be the case. Instead, the gradient in severity of the T defect may be caused by defective mesoderm cell movements, which result in a progressive accumulation of mesoderm cells near the primitive streak. Embryonic stem (ES) cells which are homozygous for the T deletion have been isolated and their differentiation in vitro and in vivo compared with that of heterozygous and wild-type ES cell lines. In +/+ ↔ T/T ES cell chimeras the Brachyury phenotype is not rescued by the presence of wild-type cells and high level chimeras show most of the features characteristic of intact T/T mutants. A few offspring from blastocysts injected with T/T ES cells have been born, several of which had greatly reduced or abnormal tails. However, little or no ES cell contribution was detectable in these animals, either as coat colour pigmentation or by isozyme analysis. Inspection of potential +/+ ↔ T/T ES cell chimeras on the 11th or 12th day of gestation, stages later than that at which intact T/T mutants die, revealed the presence of chimeras with caudal defects. These chimeras displayed a gradient of ES cell colonisation along the rostrocaudal axis with increased colonisation of caudal regions. In addition, the extent of chimerism in ectodermal tissues (which do not invaginate during gastrulation) tended to be higher than that in mesodermal tissues (which are derived from cells invaginating through the primitive streak). These results suggest that nascent mesoderm cells lacking the T gene are compromised in their ability to move away from the primitive streak. This indicates that one function of the T genemay be to regulate cell adhesion or cell motility properties in mesoderm cells. Wild-type cells in +/+ ↔ T/T chimeras appear to move normally to populate trunk and head mesoderm, suggesting that the reduced motility in T/T cells is a cell autonomous defect

Abstract 129: Embryonic Stem Cell Derived Exosomes Revive Endogenous Repair Mechanisms In Failing Heart

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Mohsin Khan ◽  
Suresh K Verma ◽  
Alexander R Mackie ◽  
Erin Vaughan ◽  
Srikanth Garikipati ◽  
...  
Keyword(s):  
Stem Cells ◽  
Therapeutic Potential ◽  
Embryonic Stem ◽  
Cardiac Regeneration ◽  
Great Promise ◽  
Target Cells ◽  
Free System ◽  
Teratoma Formation

Rationale: Embryonic stem cells (ESCs) hold great promise for cardiac regeneration but are susceptible to ethical concerns, lack of autologous donors and teratoma formation. Recently, it has been observed that beneficial effects of stem cells are mediated by exosomes secreted out under various physiological conditions. ESCs have the ability to produce exosomes however their effect in the context of the heart is unknown. Objective: Determine the effect of ESC derived exosomes for cardiac repair and modulation of CPCs functions in the heart following myocardial infarction. Methods and Results: Exosomes were isolated from murine ESCs (mES Ex) or embryonic fibroblasts (MEFs) by ultracentrifugation and verified by Flotillin-1 immunoblot analysis. Induction of pluripotent markers, survival and in vitro tube formation was enhanced in target cells receiving ESC exosomes indicating therapeutic potential of mES Ex. mES Ex administration resulted in enhanced neovascularization, cardiomyocyte survival and reduced fibrosis post infarction consistent with resurgence of cardiac proliferative response. Importantly, mES Ex mediated considerable enhancement of cardiac progenitor cell (CPC) survival, proliferation and cardiac commitment concurrent with increased c-kit+ CPCs in vivo 4 weeks after mES Ex transfer. miRNA Array analysis of ESC and MEF exosomes revealed significantly high expression of miR290-295 cluster in the ESC exosomes compared to MEF exosomes. The underlying beneficial effect of mES Ex was tied to delivery of ESC miR-294 to the heart and in particular CPCs thereby promoting CPC survival and proliferation as analyzed by FACS based cell death analysis and CyQuant assay respectively. Interestingly, enhanced G1/S transition was observed in CPCs treated with miR-294 in conjunction with significant reduction of G1 phase. Conclusion: In conclusion, mES Ex provide a novel cell free system for cardiac regeneration with the ability to modulate both cardiomyocyte and CPC based repair programs in the heart thereby avoiding the risk of teratoma formation associated with ESCs.

scholarly journals Designer blood: creating hematopoietic lineages from embryonic stem cells

Blood ◽  
2006 ◽  
Vol 107 (4) ◽  
pp. 1265-1275 ◽  
Author(s):  
Abby L. Olsen ◽  
David L. Stachura ◽  
Mitchell J. Weiss
Keyword(s):  
Stem Cells ◽  
Es Cells ◽  
Embryonic Stem ◽  
Basic Research ◽  
Cell Types ◽  
Patient Specific ◽  
Es Cell ◽  
Blood Disorders ◽  
Hematopoietic Stem

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.

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