The ground state of pluripotency

2010 ◽  
Vol 38 (4) ◽  
pp. 1027-1032 ◽  
Author(s):  
Jason Wray ◽  
Tuzer Kalkan ◽  
Austin G. Smith
Keyword(s):  
Ground State ◽  
Cell Biology ◽  
Kinase Inhibitors ◽  
Glycogen Synthase ◽  
Es Cells ◽  
Embryonic Stem ◽  
Mitogen Activated Protein Kinase ◽  
Mammalian Development ◽  
Mitogen Activated Protein ◽  
The Stability

Pluripotency is defined as the capacity of individual cells to initiate all lineages of the mature organism in response to signals from the embryo or cell culture environment. A pluripotent cell has no predetermined programme; it is a blank slate. This is the foundation of mammalian development and of ES (embryonic stem) cell biology. What are the design principles of this naïve cell state? How is pluripotency acquired and maintained? Suppressing activation of ERKs (extracellular-signal-regulated kinases) is critical to establishing and sustaining ES cells. Inhibition of GSK3 (glycogen synthase kinase 3) reinforces this effect. We review the effect of selective kinase inhibitors on pluripotent cells and consider how these effects are mediated. We propose that ES cells represent a ground state, meaning a basal proliferative state that is free of epigenetic restriction and has minimal requirements for extrinsic stimuli. The stability of this state is reflected in the homogeneity of ES cell populations cultured in the presence of small-molecule inhibitors of MEK (mitogen-activated protein kinase/ERK kinase) and GSK3.

scholarly journals Mitogen-Activated Protein Kinase Inhibitors and T-Cell-Dependent Immunotherapy in Cancer

2020 ◽  
Vol 13 (1) ◽  
pp. 9 ◽  
Author(s):  
Sandeep Kumar ◽  
Daniel R. Principe ◽  
Sunil Kumar Singh ◽  
Navin Viswakarma ◽  
Gautam Sondarva ◽  
...  
Keyword(s):  
T Cell ◽  
Protein Kinase ◽  
Tumor Cells ◽  
Cell Biology ◽  
Kinase Inhibitors ◽  
Mapk Signaling ◽  
Protein Kinase Inhibitors ◽  
Mitogen Activated Protein Kinase ◽  
Wide Range ◽  
Mitogen Activated Protein

Mitogen-activated protein kinase (MAPK) signaling networks serve to regulate a wide range of physiologic and cancer-associated cell processes. For instance, a variety of oncogenic mutations often lead to hyperactivation of MAPK signaling, thereby enhancing tumor cell proliferation and disease progression. As such, several components of the MAPK signaling network have been proposed as viable targets for cancer therapy. However, the contributions of MAPK signaling extend well beyond the tumor cells, and several MAPK effectors have been identified as key mediators of the tumor microenvironment (TME), particularly with respect to the local immune infiltrate. In fact, a blockade of various MAPK signals has been suggested to fundamentally alter the interaction between tumor cells and T lymphocytes and have been suggested a potential adjuvant to immune checkpoint inhibition in the clinic. Therefore, in this review article, we discuss the various mechanisms through which MAPK family members contribute to T-cell biology, as well as circumstances in which MAPK inhibition may potentiate or limit cancer immunotherapy.

scholarly journals β-Catenin safeguards the ground state of mousepluripotency by strengthening the robustness of the transcriptional apparatus

2020 ◽  
Vol 6 (29) ◽  
pp. eaba1593
Author(s):  
Meng Zhang ◽  
Yiwei Lai ◽  
Vladislav Krupalnik ◽  
Pengcheng Guo ◽  
Xiangpeng Guo ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Rna Polymerase Ii ◽  
Ground State ◽  
Transcription Initiation ◽  
Inner Cell Mass ◽  
Glycogen Synthase ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Mitogen Activated Protein Kinase ◽  
Cell Cycle Gene

Mouse embryonic stem cells cultured with MEK (mitogen-activated protein kinase kinase) and GSK3 (glycogen synthase kinase 3) inhibitors (2i) more closely resemble the inner cell mass of preimplantation blastocysts than those cultured with SL [serum/leukemia inhibitory factor (LIF)]. The transcriptional mechanisms governing this pluripotent ground state are unresolved. Release of promoter-proximal paused RNA polymerase II (Pol2) is a multistep process necessary for pluripotency and cell cycle gene transcription in SL. We show that β-catenin, stabilized by GSK3 inhibition in medium with 2i, supplies transcriptional coregulators at pluripotency loci. This selectively strengthens pluripotency loci and renders them addicted to transcription initiation for productive gene body elongation in detriment to Pol2 pause release. By contrast, cell cycle genes are not bound by β-catenin, and proliferation/self-renewal remains tightly controlled by Pol2 pause release under 2i conditions. Our findings explain how pluripotency is reinforced in the ground state and also provide a general model for transcriptional resilience/adaptation upon network perturbation in other contexts.

scholarly journals The Milk Thistle (Silybum marianum) Compound Silibinin Inhibits Cardiomyogenesis of Embryonic Stem Cells by Interfering with Angiotensin II Signaling

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Enas Hussein Ali ◽  
Fatemeh Sharifpanah ◽  
Amer Taha ◽  
Suk Ying Tsang ◽  
Maria Wartenberg ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Es Cells ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Mitogen Activated Protein Kinase ◽  
Milk Thistle ◽  
Ang Ii ◽  
Silybum Marianum ◽  
Angiotensin Ii Signaling ◽  
Mitogen Activated Protein

The milk thistle (Silybum marianum (L.) Gaertn.) compound silibinin may be an inhibitor of the angiotensin II type 1 (AT1) receptor which is expressed in differentiating embryonic stem (ES) cells and is involved in the regulation of cardiomyogenesis. In the present study, it was demonstrated that silibinin treatment decreased the number of spontaneously contracting cardiac foci and cardiac cell areas differentiated from ES cells as well as contraction frequency and frequency of calcium (Ca2+) spiking. In contrast, angiotensin II (Ang II) treatment stimulated cardiomyogenesis as well as contraction and Ca2+ spiking frequency, which were abolished in the presence of silibinin. Intracellular Ca2+ transients elicited by Ang II in rat smooth muscle cells were not impaired upon silibinin treatment, excluding the possibility that the compound acted on the AT1 receptor. Ang II treatment activated extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) pathways in embryoid bodies which were abolished upon silibinin pretreatment. In summary, our data suggest that silibinin inhibits cardiomyogenesis of ES cells by interfering with Ang II signaling downstream of the AT1 receptor.

Cell context–specific effects of the BCR-ABL oncogene monitored in hematopoietic progenitors

Blood ◽  
2003 ◽  
Vol 101 (10) ◽  
pp. 4088-4097 ◽  
Author(s):  
Stephane Wong ◽  
Jami McLaughlin ◽  
Donghui Cheng ◽  
Owen N. Witte
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Mapk Pathway ◽  
Es Cells ◽  
Embryonic Stem ◽  
Mitogen Activated Protein Kinase ◽  
Hematopoietic Progenitors ◽  
Mitogen Activated Protein ◽  
Context Specific

AbstractAcute BCR-ABL expression during in vitro hematopoietic development of embryonic stem (ES) cells causes expansion of multipotent and myeloid progenitors with a concomitant reduction in differentiation toward erythroblasts. Progenitor cell expansion is due to a rapid, cell autonomous, suppression of programmed cell death with an increase in expression of the antiapoptotic molecule BCL-XL. Other antiapoptotic effectors, including AKT, STAT5, and BCL-2 are not up-regulated by BCR-ABL in this system. In addition, the proapoptotic p38 mitogen–activated protein kinase (MAPK) pathway is suppressed by BCR-ABL expression in ES-derived hematopoietic progenitors. Inhibition of p38 MAPK by the small molecule inhibitor SB203580 expanded ES-derived hematopoietic progenitors by an antiapoptotic mechanism and is sufficient to expand ES-derived hematopoietic progenitors to levels approaching 80% of that seen following BCR-ABL expression. In the cellular context of ES-derived hematopoietic progenitors, BCR-ABL expression expands cells by suppressing programmed cell death with a set of antiapoptotic pathways distinct from those previously reported in continuous cell line studies.

Requirement for mitogen-activated protein kinase activation in the response of embryonic stem cell–derived hematopoietic cells to thrombopoietin in vitro

Blood ◽  
2002 ◽  
Vol 99 (4) ◽  
pp. 1174-1182 ◽  
Author(s):  
Marie-Dominique Filippi ◽  
Françoise Porteu ◽  
Françoise Le Pesteur ◽  
Valérie Schiavon ◽  
Gaël A. Millot ◽  
...  
Keyword(s):  
Growth Factors ◽  
Protein Kinase ◽  
Mapk Pathway ◽  
Es Cells ◽  
Embryonic Stem ◽  
Mitogen Activated Protein Kinase ◽  
Mapk Activation ◽  
Terminal Domain ◽  
Mitogen Activated Protein

Enforced expression of c-mpl in embryonic stem (ES) cells inactivated for this gene results in protein expression in all the ES cell progeny, producing cells that do not belong to the megakaryocytic lineage and are responsive to PEG-rhuMGDF, a truncated form of human thrombopoietin (TPO) conjugated to polyethylene glycol. These include a primitive cell called BL-CFC, thought to represent the equivalent of the hemangioblast, and all myeloid progenitor cells. In this model, PEG-rhuMGDF was able to potentiate the stimulating effects of other growth factors, including vascular endothelial growth factor, on BL-CFC and a combination of cytokines on the growth of granulocyte macrophage–colony-forming units. The importance of the C-terminal domain of Mpl and of mitogen-activated protein kinase (MAPK) activation in TPO-dependent megakaryocytic differentiation has been well studied in vitro. Here, the role of this domain and the involvement of MAPK in upstream and nonmegakaryocytic cells are examined by using 2 truncated mutants of Mpl (Δ34, deletion of residues 71 to 121 in the C-terminal domain; and Δ3, deletion of residues 71-94) and specific inhibitors of the MAPK pathway. The 2 deleted regions support different functions, mediated by different signals. Residues 71 to 121 were required for PEG-rhuMGDF–dependent growth of BL-CFC, for megakaryocytic and other myeloid progenitors, and for megakaryocyte polyploidization. These responses were mediated by the ERK1–ERK2 MAPK pathway. In contrast, the only function of the sequence comprising residues 71 to 94 was to mediate the synergistic effects of PEG-rhuMGDF with other hematopoietic growth factors. This function is not mediated by MAPK activation.

scholarly journals When Good Kinases Go Rogue: GSK3, p38 MAPK and CDKs as Therapeutic Targets for Alzheimer’s and Huntington’s Disease

2021 ◽  
Vol 22 (11) ◽  
pp. 5911
Author(s):  
Santosh R. D’Mello
Keyword(s):  
Neurodegenerative Diseases ◽  
Huntington's Disease ◽  
Huntington’S Disease ◽  
P38 Mapk ◽  
Cell Biology ◽  
Kinase Inhibitors ◽  
Glycogen Synthase ◽  
Mitogen Activated Protein Kinase ◽  
Brain Disorder ◽  
Motor Abnormalities

Alzheimer’s disease (AD) is a mostly sporadic brain disorder characterized by cognitive decline resulting from selective neurodegeneration in the hippocampus and cerebral cortex whereas Huntington’s disease (HD) is a monogenic inherited disorder characterized by motor abnormalities and psychiatric disturbances resulting from selective neurodegeneration in the striatum. Although there have been numerous clinical trials for these diseases, they have been unsuccessful. Research conducted over the past three decades by a large number of laboratories has demonstrated that abnormal actions of common kinases play a key role in the pathogenesis of both AD and HD as well as several other neurodegenerative diseases. Prominent among these kinases are glycogen synthase kinase (GSK3), p38 mitogen-activated protein kinase (MAPK) and some of the cyclin-dependent kinases (CDKs). After a brief summary of the molecular and cell biology of AD and HD this review covers what is known about the role of these three groups of kinases in the brain and in the pathogenesis of the two neurodegenerative disorders. The potential of targeting GSK3, p38 MAPK and CDKS as effective therapeutics is also discussed as is a brief discussion on the utilization of recently developed drugs that simultaneously target two or all three of these groups of kinases. Multi-kinase inhibitors either by themselves or in combination with strategies currently being used such as immunotherapy or secretase inhibitors for AD and knockdown for HD could represent a more effective therapeutic approach for these fatal neurodegenerative diseases.

scholarly journals A Haplolethal Locus Uncovered by Deletions in the Mouse t Complex

Genetics ◽  
2002 ◽  
Vol 160 (2) ◽  
pp. 675-682
Author(s):  
Victoria L Browning ◽  
Rebecca A Bergstrom ◽  
Sandra Daigle ◽  
John C Schimenti
Keyword(s):  
Gene Dosage ◽  
Es Cells ◽  
Embryonic Stem ◽  
Chromosome 17 ◽  
Mammalian Development ◽  
T Complex ◽  
Segmental Aneuploidy ◽  
Systematic Exploration ◽  
Radiation Induced ◽  
Altered Gene

Abstract Proper levels of gene expression are important for normal mammalian development. Typically, altered gene dosage caused by karyotypic abnormalities results in embryonic lethality or birth defects. Segmental aneuploidy can be compatible with life but often results in contiguous gene syndromes. The ability to manipulate the mouse genome allows the systematic exploration of regions that are affected by alterations in gene dosage. To explore the effects of segmental haploidy in the mouse t complex on chromosome 17, radiation-induced deletion complexes centered at the Sod2 and D17Leh94 loci were generated in embryonic stem (ES) cells. A small interval was identified that, when hemizygous, caused specific embryonic lethal phenotypes (exencephaly and edema) in most fetuses. The penetrance of these phenotypes was background dependent. Additionally, evidence for parent-of-origin effects was observed. This genetic approach should be useful for identifying genes that are imprinted or whose dosage is critical for normal embryonic development.

scholarly journals Retinoic acid signaling is critical during the totipotency window in early mammalian development

2021 ◽  
Author(s):  
Ane Iturbide ◽  
Mayra L. Ruiz Tejeda Segura ◽  
Camille Noll ◽  
Kenji Schorpp ◽  
Ina Rothenaigner ◽  
...  
Keyword(s):  
Retinoic Acid ◽  
Regulatory Networks ◽  
Es Cells ◽  
Embryonic Stem ◽  
Mammalian Development ◽  
Cell Stage ◽  
Cell Potential ◽  
Cellular Models ◽  
Early Embryos ◽  
Genome Activation

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.

scholarly journals Mouse embryonic stem cell-derived cardiomyocytes cease to beat following exposure to monochromatic light: association with increased ROS and loss of calcium transients

2019 ◽  
Vol 317 (4) ◽  
pp. C725-C736
Author(s):  
Gurbind Singh ◽  
Divya Sridharan ◽  
Mahmood Khan ◽  
Polani B. Seshagiri
Keyword(s):  
Cell Biology ◽  
Fluorescent Protein ◽  
Es Cells ◽  
Monochromatic Light ◽  
Embryonic Stem ◽  
Mouse Embryonic Stem Cell ◽  
Medical Diagnostics ◽  
Calcium Transients ◽  
Egfp Expression ◽  
Mitochondrial Activity

We earlier established the mouse embryonic stem (ES) cell “GS-2” line expressing enhanced green fluorescent protein (EGFP) and have been routinely using it to understand the molecular regulation of differentiation into cardiomyocytes. During such studies, we made a serendipitous discovery that functional cardiomyocytes derived from ES cells stopped beating when exposed to blue light. We observed a gradual cessation of contractility within a few minutes, regardless of wavelength (nm) ranges tested: blue (~420–495), green (~510–575), and red (~600–700), with green light manifesting the strongest impact. Following shifting of cultures back into the incubator (darkness), cardiac clusters regained beatings within a few hours. The observed light-induced contractility-inhibition effect was intrinsic to cardiomyocytes and not due to interference from other cell types. Also, this was not influenced by any physicochemical parameters or intracellular EGFP expression. Interestingly, the light-induced cardiomyocyte contractility inhibition was accompanied by increased intracellular reactive oxygen species (ROS), which could be abolished in the presence of N-acetylcysteine (ROS quencher). Besides, the increased intracardiomyocyte ROS levels were incidental to the inhibition of calcium transients and suppression of mitochondrial activity, both being essential for sarcomere function. To the best of our knowledge, ours is the first report to demonstrate the monochromatic light-mediated inhibition of contractions of cardiomyocytes with no apparent loss of cell viability and contractility. Our findings have implications in cardiac cell biology context in terms of 1) mechanistic insights into light impact on cardiomyocyte contraction, 2) potential use in laser beam-guided (cardiac) microsurgery, photo-optics-dependent medical diagnostics, 3) transient cessation of hearts during coronary artery bypass grafting, and 4) functional preservation of hearts for transplantation.

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