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Sample records for cell fate choice

  1. Commentary: Cell fate choice and social evolution in Dictyostelium ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Biosciences; Volume 26; Issue 2. Commentary: Cell fate choice and social evolution in Dictyostelium discoideum: Interplay of morphogens and heterogeneities. Trupti S Kawli Sonia Kaushik. Volume 26 Issue 2 June 2001 pp 130-133 ...

  2. Temporal competition between differentiation programs determines cell fate choice

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    Kuchina, Anna; Espinar, Lorena; Cagatay, Tolga; Balbin, Alejandro; Alvarado, Alma; Garcia-Ojalvo, Jordi; Suel, Gurol

    2011-03-01

    During pluripotent differentiation, cells adopt one of several distinct fates. The dynamics of this decision-making process are poorly understood, since cell fate choice may be governed by interactions between differentiation programs that are active at the same time. We studied the dynamics of decision-making in the model organism Bacillus subtilis by simultaneously measuring the activities of competing differentiation programs (sporulation and competence) in single cells. We discovered a precise switch-like point of cell fate choice previously hidden by cell-cell variability. Engineered artificial crosslinks between competence and sporulation circuits revealed that the precision of this choice is generated by temporal competition between the key players of two differentiation programs. Modeling suggests that variable progression towards a switch-like decision might represent a general strategy to maximize adaptability and robustness of cellular decision-making.

  3. Cell fate choice and social evolution in Dictyostelium discoideum ...

    Indian Academy of Sciences (India)

    Cell fate choice and social evolution in. Dictyostelium discoideum: Interplay of morphogens and heterogeneities. Attempts to understand the development of the social amoeba Dictyostelium discoideum keep throwing up surprises and drive home the point that here too, as in any biological situation, no explanation can.

  4. Roles of Notch1 Signaling in Regulating Satellite Cell Fates Choices and Postnatal Skeletal Myogenesis.

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    Shan, Tizhong; Xu, Ziye; Wu, Weiche; Liu, Jiaqi; Wang, Yizhen

    2017-11-01

    Adult skeletal muscle stem cells, also called satellite cells, are indispensable for the growth, maintenance, and regeneration of the postnatal skeletal muscle. Satellite cells, predominantly quiescent in mature resting muscles, are activated after skeletal muscle injury or degeneration. Notch1 signaling is an evolutionarily conserved pathway that plays crucial roles in satellite cells homeostasis and postnatal skeletal myogenesis and regeneration. Activation of Notch1 signaling promotes the muscle satellite cells quiescence and proliferation, but inhibits differentiation of muscle satellite cells. Notably, the new roles of Notch1 signaling during late-stage of skeletal myogenesis including in post-differentiation myocytes and post-fusion myotubes have been recently reported. Here, we mainly review and discuss the regulatory roles of Notch1 in regulating satellite cell fates choices and skeletal myogenesis. J. Cell. Physiol. 232: 2964-2967, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  5. The C. elegans TPR Containing Protein, TRD-1, Regulates Cell Fate Choice in the Developing Germ Line and Epidermis.

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    Samantha Hughes

    Full Text Available Correct cell fate choice is crucial in development. In post-embryonic development of the hermaphroditic Caenorhabitis elegans, distinct cell fates must be adopted in two diverse tissues. In the germline, stem cells adopt one of three possible fates: mitotic cell cycle, or gamete formation via meiosis, producing either sperm or oocytes. In the epidermis, the stem cell-like seam cells divide asymmetrically, with the daughters taking on either a proliferative (seam or differentiated (hypodermal or neuronal fate. We have isolated a novel conserved C. elegans tetratricopeptide repeat containing protein, TRD-1, which is essential for cell fate determination in both the germline and the developing epidermis and has homologs in other species, including humans (TTC27. We show that trd-1(RNAi and mutant animals have fewer seam cells as a result of inappropriate differentiation towards the hypodermal fate. In the germline, trd-1 RNAi results in a strong masculinization phenotype, as well as defects in the mitosis to meiosis switch. Our data suggests that trd-1 acts downstream of tra-2 but upstream of fem-3 in the germline sex determination pathway, and exhibits a constellation of phenotypes in common with other Mog (masculinization of germline mutants. Thus, trd-1 is a new player in both the somatic and germline cell fate determination machinery, suggestive of a novel molecular connection between the development of these two diverse tissues.

  6. A Molecular Switch Regulating Cell Fate Choice between Muscle Progenitor Cells and Brown Adipocytes.

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    An, Yitai; Wang, Gang; Diao, Yarui; Long, Yanyang; Fu, Xinrong; Weng, Mingxi; Zhou, Liang; Sun, Kun; Cheung, Tom H; Ip, Nancy Y; Sun, Hao; Wang, Huating; Wu, Zhenguo

    2017-05-22

    During mouse embryo development, both muscle progenitor cells (MPCs) and brown adipocytes (BAs) are known to derive from the same Pax7 + /Myf5 + progenitor cells. However, the underlying mechanisms for the cell fate control remain unclear. In Pax7-null MPCs from young mice, several BA-specific genes, including Prdm16 and Ucp1 and many other adipocyte-related genes, were upregulated with a concomitant reduction of Myod and Myf5, two muscle lineage-determining genes. This suggests a cell fate switch from MPC to BA. Consistently, freshly isolated Pax7-null but not wild-type MPCs formed lipid-droplet-containing UCP1 + BA in culture. Mechanistically, MyoD and Myf5, both known transcription targets of Pax7 in MPC, potently repress Prdm16, a BA-specific lineage-determining gene, via the E2F4/p107/p130 transcription repressor complex. Importantly, inducible Pax7 ablation in developing mouse embryos promoted brown fat development. Thus, the MyoD/Myf5-E2F4/p107/p130 axis functions in both the Pax7 + /Myf5 + embryonic progenitor cells and postnatal myoblasts to repress the alternative BA fate. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Dynamic Pax6 expression during the neurogenic cell cycle influences proliferation and cell fate choices of retinal progenitors

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    Yang Xian-Jie

    2009-08-01

    Full Text Available Abstract Background The paired homeobox protein Pax6 is essential for proliferation and pluripotency of retinal progenitors. However, temporal changes in Pax6 protein expression associated with the generation of various retinal neurons have not been characterized with regard to the cell cycle. Here, we examine the dynamic changes of Pax6 expression among chicken retinal progenitors as they progress through the neurogenic cell cycle, and determine the effects of altered Pax6 levels on retinogenesis. Results We provide evidence that during the preneurogenic to neurogenic transition, Pax6 protein levels in proliferating progenitor cells are down-regulated. Neurogenic retinal progenitors retain a relatively low level of Pax6 protein, whereas postmitotic neurons either elevate or extinguish Pax6 expression in a cell type-specific manner. Cell imaging and cell cycle analyses show that neurogenic progenitors in the S phase of the cell cycle contain low levels of Pax6 protein, whereas a subset of progenitors exhibits divergent levels of Pax6 protein upon entering the G2 phase of the cell cycle. We also show that M phase cells contain varied levels of Pax6, and some correlate with the onset of early neuronal marker expression, forecasting cell cycle exit and cell fate commitment. Furthermore, either elevating or knocking down Pax6 attenuates cell proliferation and results in increased cell death. Reducing Pax6 decreases retinal ganglion cell genesis and enhances cone photoreceptor and amacrine interneuron production, whereas elevating Pax6 suppresses cone photoreceptor and amacrine cell fates. Conclusion These studies demonstrate for the first time quantitative changes in Pax6 protein expression during the preneurogenic to neurogenic transition and during the neurogenic cell cycle. The results indicate that Pax6 protein levels are stringently controlled in proliferating progenitors. Maintaining a relatively low Pax6 protein level is necessary for S phase

  8. Real-time imaging of bHLH transcriptional factors reveals their dynamic control in the multipotency and fate choice of neural stem cells

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    Itaru eImayoshi

    2015-08-01

    Full Text Available The basic-helix-loop-helix (bHLH transcription factors Ascl1/Mash1, Hes1, and Olig2 regulate the fate choice of neurons, astrocytes, and oligodendrocytes, respectively; however, these factors are coexpressed in self-renewing multipotent neural stem cells (NSCs even before cell fate determination. This fact raises the possibility these fate determination factors are differentially expressed between self-renewing and differentiating NSCs with unique expression dynamics. Real-time imaging analysis utilizing fluorescent proteins is a powerful strategy for monitoring expression dynamics. Fusion with fluorescent reporters makes it possible to analyze the dynamic behavior of specific proteins in living cells. However, it is technically challenging to conduct long-term imaging of proteins, particularly those with low expression levels, because a high-sensitivity and low-noise imaging system is required, and very often bleaching of fluorescent proteins and cell toxicity by prolonged laser exposure are problematic. Furthermore, to analyze the functional roles of the dynamic expression of cellular proteins, it is essential to image reporter fusion proteins that are expressed at comparable levels to their endogenous expression. In this review, we introduce our recent reports about the dynamic control of bHLH transcription factors in multipotency and fate choice of NSCs, focusing on real-time imaging of fluorescent reporters fused with bHLH transcription factors. Our imaging results indicate that bHLH transcription factors are expressed in an oscillatory manner by NSCs, and that one of them becomes dominant during fate choice. We propose that the multipotent state of NSCs correlates with the oscillatory expression of several bHLH transcription factors, whereas the differentiated state correlates with the sustained expression of a single bHLH transcription factor.

  9. Non-genetic heterogeneity and cell fate choice in Dictyostelium discoideum.

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    Chattwood, Alex; Thompson, Christopher R L

    2011-05-01

    From microbes to metazoans, it is now clear that fluctuations in the abundance of mRNA transcripts and protein molecules enable genetically identical cells to oscillate between several distinct states (Kaern et al. 2005). Since this cell-cell variability does not derive from physical differences in the genetic code it is termed non-genetic heterogeneity. Non-genetic heterogeneity endows cell populations with useful capabilities they could never achieve if each cell were the same as its neighbors (Raj & van Oudenaarden 2008; Eldar & Elowitz 2010). One such example is seen during multicellular development and "salt and pepper" cell type differentiation. In this review, we will first examine the importance of non-genetic heterogeneity in initiating "salt and pepper" pattern formation during Dictyostelium discoideum development. Second, we will discuss the various ways in which non-genetic heterogeneity might be generated, as well as recent advances in understanding the molecular basis of heterogeneity in this system. © 2011 The Authors. Development, Growth & Differentiation © 2011 Japanese Society of Developmental Biologists.

  10. Cell fate determination dynamics in bacteria

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    Kuchina, Anna; Espinar, Lorena; Cagatay, Tolga; Garcia-Ojalvo, Jordi; Suel, Gurol

    2010-03-01

    The fitness of an organism depends on many processes that serve the purpose to adapt to changing environment in a robust and coordinated fashion. One example of such process is cellular fate determination. In the presence of a variety of alternative responses each cell adopting a particular fate represents a ``choice'' that must be tightly regulated to ensure the best survival strategy for the population taking into account the broad range of possible environmental challenges. We investigated this problem in the model organism B.Subtilis which under stress conditions differentiates terminally into highly resistant spores or initiates an alternative transient state of competence. The dynamics underlying cell fate choice remains largely unknown. We utilize quantitative fluorescent microscopy to track the activities of genes involved in these responses on a single-cell level. We explored the importance of temporal interactions between competing cell fates by re- engineering the differentiation programs. I will discuss how the precise dynamics of cellular ``decision-making'' governed by the corresponding biological circuits may enable cells to adjust to diverse environments and determine survival.

  11. Matrix control of stem cell fate.

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    Even-Ram, Sharona; Artym, Vira; Yamada, Kenneth M

    2006-08-25

    A key challenge in stem cell research is to learn how to direct the differentiation of stem cells toward specific fates. In this issue of Cell, Engler et al. (2006) identify a new factor regulating stem cell fate: the elasticity of the matrix microenvironment. By changing the stiffness of the substrate, human mesenchymal stem cells could be directed along neuronal, muscle, or bone lineages.

  12. BTG interacts with retinoblastoma to control cell fate in Dictyostelium.

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    Daniele Conte

    Full Text Available BACKGROUND: In the genesis of many tissues, a phase of cell proliferation is followed by cell cycle exit and terminal differentiation. The latter two processes overlap: genes involved in the cessation of growth may also be important in triggering differentiation. Though conceptually distinct, they are often causally related and functional interactions between the cell cycle machinery and cell fate control networks are fundamental to coordinate growth and differentiation. A switch from proliferation to differentiation may also be important in the life cycle of single-celled organisms, and genes which arose as regulators of microbial differentiation may be conserved in higher organisms. Studies in microorganisms may thus contribute to understanding the molecular links between cell cycle machinery and the determination of cell fate choice networks. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that in the amoebozoan D. discoideum, an ortholog of the metazoan antiproliferative gene btg controls cell fate, and that this function is dependent on the presence of a second tumor suppressor ortholog, the retinoblastoma-like gene product. Specifically, we find that btg-overexpressing cells preferentially adopt a stalk cell (and, more particularly, an Anterior-Like Cell fate. No btg-dependent preference for ALC fate is observed in cells in which the retinoblastoma-like gene has been genetically inactivated. Dictyostelium btg is the only example of non-metazoan member of the BTG family characterized so far, suggesting that a genetic interaction between btg and Rb predated the divergence between dictyostelids and metazoa. CONCLUSIONS/SIGNIFICANCE: While the requirement for retinoblastoma function for BTG antiproliferative activity in metazoans is known, an interaction of these genes in the control of cell fate has not been previously documented. Involvement of a single pathway in the control of mutually exclusive processes may have relevant implication in the

  13. Cell Fate Decision Making through Oriented Cell Division

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    Johnston, Christopher A.

    2016-01-01

    The ability to dictate cell fate decisions is critical during animal development. Moreover, faithful execution of this process ensures proper tissue homeostasis throughout adulthood, whereas defects in the molecular machinery involved may contribute to disease. Evolutionarily conserved protein complexes control cell fate decisions across diverse tissues. Maintaining proper daughter cell inheritance patterns of these determinants during mitosis is therefore a fundamental step of the cell fate decision-making process. In this review, we will discuss two key aspects of this fate determinant segregation activity, cortical cell polarity and mitotic spindle orientation, and how they operate together to produce oriented cell divisions that ultimately influence daughter cell fate. Our focus will be directed at the principal underlying molecular mechanisms and the specific cell fate decisions they have been shown to control. PMID:26844213

  14. Biomaterial stiffness determines stem cell fate.

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    Lv, Hongwei; Wang, Heping; Zhang, Zhijun; Yang, Wang; Liu, Wenbin; Li, Yulin; Li, Lisha

    2017-06-01

    Stem cells have potential to develop into numerous cell types, thus they are good cell source for tissue engineering. As an external physical signal, material stiffness is capable of regulating stem cell fate. Biomaterial stiffness is an important parameter in tissue engineering. We summarize main measurements of material stiffness under different condition, then list and compare three main methods of controlling stiffness (material amount, crosslinking density and photopolymeriztion time) which interplay with one another and correlate with stiffness positively, and current advances in effects of biomaterial stiffness on stem cell fate. We discuss the unsolved problems and future directions of biomaterial stiffness in tissue engineering. Copyright © 2017. Published by Elsevier Inc.

  15. Fate of micronuclei and micronucleated cells.

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    Hintzsche, Henning; Hemmann, Ulrike; Poth, Albrecht; Utesch, Dietmar; Lott, Jasmin; Stopper, Helga

    The present review describes available evidence about the fate of micronuclei and micronucleated cells. Micronuclei are small, extranuclear chromatin bodies surrounded by a nuclear envelope. The mechanisms underlying the formation of micronuclei are well understood but not much is known about the potential fate of micronuclei and micronucleated cells. Many studies with different experimental approaches addressed the various aspects of the post-mitotic fate of micronuclei and micronucleated cells. These studies are reviewed here considering four basic possibilities for potential fates of micronuclei: degradation of the micronucleus or the micronucleated cell, reincorporation into the main nucleus, extrusion from the cell, and persistence in the cytoplasm. Two additional fates need to be considered: premature chromosome condensation/chromothripsis and the elimination of micronucleated cells by apoptosis, yielding six potential fates for micronuclei and/or micronucleated cells. The available data is still limited, but it can be concluded that degradation and extrusion of micronuclei might occur in rare cases under specific conditions, reincorporation during the next mitosis occurs more frequently, and the majority of the micronuclei persist without alteration at least until the next mitosis, possibly much longer. Overall, the consequences of micronucleus formation on the cellular level are still far from clear, but they should be investigated further because micronucleus formation may contribute to the initial and later steps of malignant cell transformation, by causing gain or loss of genetic material in the daughter cells and by the possibility of massive chromosome rearrangement in chromosomes entrapped within a micronucleus by the mechanisms of chromothripsis and chromoanagenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Harnessing cell-material interaction to control cell fate: design ...

    Indian Academy of Sciences (India)

    Rajat K Das

    2017-10-26

    Oct 26, 2017 ... advancement in engineered hydrogel materials as such scaffold to control cell fate. Keywords. Extracellular matrix; hydrogel .... tandem and determine the fate of the stem cells (cytoskeletal actin re-organization, gene ..... (encapsulation and on-demand release of therapeutic cells). These examples indicate ...

  17. Binary cell fate decisions and fate transformation in the Drosophila larval eye.

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    Abhishek Kumar Mishra

    Full Text Available The functionality of sensory neurons is defined by the expression of specific sensory receptor genes. During the development of the Drosophila larval eye, photoreceptor neurons (PRs make a binary choice to express either the blue-sensitive Rhodopsin 5 (Rh5 or the green-sensitive Rhodopsin 6 (Rh6. Later during metamorphosis, ecdysone signaling induces a cell fate and sensory receptor switch: Rh5-PRs are re-programmed to express Rh6 and become the eyelet, a small group of extraretinal PRs involved in circadian entrainment. However, the genetic and molecular mechanisms of how the binary cell fate decisions are made and switched remain poorly understood. We show that interplay of two transcription factors Senseless (Sens and Hazy control cell fate decisions, terminal differentiation of the larval eye and its transformation into eyelet. During initial differentiation, a pulse of Sens expression in primary precursors regulates their differentiation into Rh5-PRs and repression of an alternative Rh6-cell fate. Later, during the transformation of the larval eye into the adult eyelet, Sens serves as an anti-apoptotic factor in Rh5-PRs, which helps in promoting survival of Rh5-PRs during metamorphosis and is subsequently required for Rh6 expression. Comparably, during PR differentiation Hazy functions in initiation and maintenance of rhodopsin expression. Hazy represses Sens specifically in the Rh6-PRs, allowing them to die during metamorphosis. Our findings show that the same transcription factors regulate diverse aspects of larval and adult PR development at different stages and in a context-dependent manner.

  18. Cell fate and cell differentiation status in the Arabidopsis root

    NARCIS (Netherlands)

    Scheres, B.J.G.; Berg, C. van den; Weisbeek, P.

    1998-01-01

    Post-embryonic development in plants is mainly achieved by its meristems. Within the Arabidopsis root meristem, both the fate and origin of its cells can be predicted with high accuracy. Mutants defective in the determination of root cell fates show that the corresponding genes are first required

  19. Specifying and protecting germ cell fate

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    Strome, Susan; Updike, Dustin

    2015-01-01

    Germ cells are the special cells in the body that undergo meiosis to generate gametes and subsequently entire new organisms after fertilization, a process that continues generation after generation. Recent studies have expanded our understanding of the factors and mechanisms that specify germ cell fate, including the partitioning of maternally supplied ‘germ plasm’, inheritance of epigenetic memory and expression of transcription factors crucial for primordial germ cell (PGC) development. Even after PGCs are specified, germline fate is labile and thus requires protective mechanisms, such as global transcriptional repression, chromatin state alteration and translation of only germline-appropriate transcripts. Findings from diverse species continue to provide insights into the shared and divergent needs of these special reproductive cells. PMID:26122616

  20. Photoreceptor cell fate specification in vertebrates

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    Brzezinski, Joseph A.; Reh, Thomas A.

    2015-01-01

    Photoreceptors – the light-sensitive cells in the vertebrate retina – have been extremely well-characterized with regards to their biochemistry, cell biology and physiology. They therefore provide an excellent model for exploring the factors and mechanisms that drive neural progenitors into a differentiated cell fate in the nervous system. As a result, great progress in understanding the transcriptional network that controls photoreceptor specification and differentiation has been made over the last 20 years. This progress has also enabled the production of photoreceptors from pluripotent stem cells, thereby aiding the development of regenerative medical approaches to eye disease. In this Review, we outline the signaling and transcription factors that drive vertebrate photoreceptor development and discuss how these function together in gene regulatory networks to control photoreceptor cell fate specification. PMID:26443631

  1. Gene expression dynamics during cell differentiation: Cell fates as attractors and cell fate decisions as bifurcations

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    Huang, Sui

    2006-03-01

    During development of multicellular organisms, multipotent stem and progenitor cells undergo a series of hierarchically organized ``somatic speciation'' processes consisting of binary branching events to achieve the diversity of discretely distinct differentiated cell types in the body. Current paradigms of genetic regulation of development do not explain this discreteness, nor the time-irreversibility of differentiation. Each cell contains the same genome with the same N (˜ 25,000) genes and each cell type k is characterized by a distinct stable gene activation pattern, expressed as the cell state vector Sk(t) = xk1(t) ,.. xki(t),.. xkN(t), where xki is the activation state of gene i in cell type k. Because genes are engaged in a network of mutual regulatory interactions, the movement of Sk(t) in the N-dimensional state space is highly constrained and the organism can only realize a tiny fraction of all possible configurations Sk. Then, the trajectories of Sk reflect the diversifying developmental paths and the mature cell types are high-dimensional attractor states. Experimental results based on gene expression profile measurements during blood cell differentiation using DNA microarrays are presented that support the old idea that cell types are attractors. This basic notion is extended to treat binary fate decisions as bifurcations in the dynamics of networks circuits. Specifically, during cell fate decision, the metastable progenitor attractor is destabilized, poising the cell on a `watershed state' so that it can stochastically or in response to deterministic perturbations enter either one of two alternative fates. Overall, the model and supporting experimental data provide an overarching conceptual framework that helps explain how the specifics of gene network architecture produces discreteness and robustness of cell types, allows for both stochastic and deterministic cell fate decision and ensures directionality of organismal development.

  2. Developmental Competence for Primordial Germ Cell Fate.

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    Günesdogan, Ufuk; Surani, M Azim

    2016-01-01

    During mammalian embryonic development, the trophectoderm and primitive endoderm give rise to extraembryonic tissues, while the epiblast differentiates into all somatic lineages and the germline. Remarkably, only a few classes of signaling pathways induce the differentiation of these progenitor cells into diverse lineages. Accordingly, the functional outcome of a particular signal depends on the developmental competence of the target cells. Thus, developmental competence can be defined as the ability of a cell to integrate intrinsic and extrinsic cues to execute a specific developmental program toward a specific cell fate. Downstream of signaling, there is the combinatorial activity of transcription factors and their cofactors, which is modulated by the chromatin state of the target cells. Here, we discuss the concept of developmental competence, and the factors that regulate this state with reference to the specification of mammalian primordial germ cells. © 2016 Elsevier Inc. All rights reserved.

  3. Synthetic RNA Controllers for Programming Mammalian Cell Fate and Function

    Science.gov (United States)

    2015-11-04

    Final report for “Synthetic RNA controllers for programming mammalian cell fate and function” Principal Investigator: Christina D. Smolke...SUBTITLE Synthetic RNA controllers for programming mammalian cell fate and function 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18   2 Synthetic RNA controllers for programming mammalian cell fate and function Task 1

  4. Competition in notch signaling with cis enriches cell fate decisions.

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    Pau Formosa-Jordan

    Full Text Available Notch signaling is involved in cell fate choices during the embryonic development of Metazoa. Commonly, Notch signaling arises from the binding of the Notch receptor to its ligands in adjacent cells driving cell-to-cell communication. Yet, cell-autonomous control of Notch signaling through both ligand-dependent and ligand-independent mechanisms is known to occur as well. Examples include Notch signaling arising in the absence of ligand binding, and cis-inhibition of Notch signaling by titration of the Notch receptor upon binding to its ligands within a single cell. Increasing experimental evidences support that the binding of the Notch receptor with its ligands within a cell (cis-interactions can also trigger a cell-autonomous Notch signal (cis-signaling, whose potential effects on cell fate decisions and patterning remain poorly understood. To address this question, herein we mathematically and computationally investigate the cell states arising from the combination of cis-signaling with additional Notch signaling sources, which are either cell-autonomous or involve cell-to-cell communication. Our study shows that cis-signaling can switch from driving cis-activation to effectively perform cis-inhibition and identifies under which conditions this switch occurs. This switch relies on the competition between Notch signaling sources, which share the same receptor but differ in their signaling efficiency. We propose that the role of cis-interactions and their signaling on fine-grained patterning and cell fate decisions is dependent on whether they drive cis-inhibition or cis-activation, which could be controlled during development. Specifically, cis-inhibition and not cis-activation facilitates patterning and enriches it by modulating the ratio of cells in the high-ligand expression state, by enabling additional periodic patterns like stripes and by allowing localized patterning highly sensitive to the precursor state and cell-autonomous bistability

  5. SPE-44 implements sperm cell fate.

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    Madhura Kulkarni

    Full Text Available The sperm/oocyte decision in the hermaphrodite germline of Caenorhabditis elegans provides a powerful model for the characterization of stem cell fate specification and differentiation. The germline sex determination program that governs gamete fate has been well studied, but direct mediators of cell-type-specific transcription are largely unknown. We report the identification of spe-44 as a critical regulator of sperm gene expression. Deletion of spe-44 causes sperm-specific defects in cytokinesis, cell cycle progression, and organelle assembly resulting in sterility. Expression of spe-44 correlates precisely with spermatogenesis and is regulated by the germline sex determination pathway. spe-44 is required for the appropriate expression of several hundred sperm-enriched genes. The SPE-44 protein is restricted to the sperm-producing germline, where it localizes to the autosomes (which contain sperm genes but is excluded from the transcriptionally silent X chromosome (which does not. The orthologous gene in other Caenorhabditis species is similarly expressed in a sex-biased manner, and the protein likewise exhibits autosome-specific localization in developing sperm, strongly suggestive of an evolutionarily conserved role in sperm gene expression. Our analysis represents the first identification of a transcriptional regulator whose primary function is the control of gamete-type-specific transcription in this system.

  6. Redox regulation of plant stem cell fate.

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    Zeng, Jian; Dong, Zhicheng; Wu, Haijun; Tian, Zhaoxia; Zhao, Zhong

    2017-10-02

    Despite the importance of stem cells in plant and animal development, the common mechanisms of stem cell maintenance in both systems have remained elusive. Recently, the importance of hydrogen peroxide (H2O2) signaling in priming stem cell differentiation has been extensively studied in animals. Here, we show that different forms of reactive oxygen species (ROS) have antagonistic roles in plant stem cell regulation, which were established by distinct spatiotemporal patterns of ROS-metabolizing enzymes. The superoxide anion (O2·-) is markedly enriched in stem cells to activate WUSCHEL and maintain stemness, whereas H2O2 is more abundant in the differentiating peripheral zone to promote stem cell differentiation. Moreover, H2O2 negatively regulates O2·- biosynthesis in stem cells, and increasing H2O2 levels or scavenging O2·- leads to the termination of stem cells. Our results provide a mechanistic framework for ROS-mediated control of plant stem cell fate and demonstrate that the balance between O2·- and H2O2 is key to stem cell maintenance and differentiation. © 2017 The Authors.

  7. The cell-cycle state of stem cells determines cell fate propensity.

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    Pauklin, Siim; Vallier, Ludovic

    2013-09-26

    Self-renewal and differentiation of stem cells are fundamentally associated with cell-cycle progression to enable tissue specification, organ homeostasis, and potentially tumorigenesis. However, technical challenges have impaired the study of the molecular interactions coordinating cell fate choice and cell-cycle progression. Here, we bypass these limitations by using the FUCCI reporter system in human pluripotent stem cells and show that their capacity of differentiation varies during the progression of their cell cycle. These mechanisms are governed by the cell-cycle regulators cyclin D1-3 that control differentiation signals such as the TGF-β-Smad2/3 pathway. Conversely, cell-cycle manipulation using a small molecule directs differentiation of hPSCs and provides an approach to generate cell types with a clinical interest. Our results demonstrate that cell fate decisions are tightly associated with the cell-cycle machinery and reveal insights in the mechanisms synchronizing differentiation and proliferation in developing tissues. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. The Cell-Cycle State of Stem Cells Determines Cell Fate Propensity

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    Pauklin, Siim; Vallier, Ludovic

    2013-01-01

    Summary Self-renewal and differentiation of stem cells are fundamentally associated with cell-cycle progression to enable tissue specification, organ homeostasis, and potentially tumorigenesis. However, technical challenges have impaired the study of the molecular interactions coordinating cell fate choice and cell-cycle progression. Here, we bypass these limitations by using the FUCCI reporter system in human pluripotent stem cells and show that their capacity of differentiation varies during the progression of their cell cycle. These mechanisms are governed by the cell-cycle regulators cyclin D1–3 that control differentiation signals such as the TGF-β-Smad2/3 pathway. Conversely, cell-cycle manipulation using a small molecule directs differentiation of hPSCs and provides an approach to generate cell types with a clinical interest. Our results demonstrate that cell fate decisions are tightly associated with the cell-cycle machinery and reveal insights in the mechanisms synchronizing differentiation and proliferation in developing tissues. PMID:24074866

  9. Cell fate determination in the Caenorhabditis elegans epidermal lineages

    NARCIS (Netherlands)

    Soete, G.A.J.

    2007-01-01

    The starting point for this work was to use the hypodermal seam of C. elegans as a model system to study cell fate determination. Even though the seam is a relatively simple developmental system, the mechanisms that control cell fate determination in the seam lineages are connected in a highly

  10. A polynomial based model for cell fate prediction in human diseases.

    Science.gov (United States)

    Ma, Lichun; Zheng, Jie

    2017-12-21

    Cell fate regulation directly affects tissue homeostasis and human health. Research on cell fate decision sheds light on key regulators, facilitates understanding the mechanisms, and suggests novel strategies to treat human diseases that are related to abnormal cell development. In this study, we proposed a polynomial based model to predict cell fate. This model was derived from Taylor series. As a case study, gene expression data of pancreatic cells were adopted to test and verify the model. As numerous features (genes) are available, we employed two kinds of feature selection methods, i.e. correlation based and apoptosis pathway based. Then polynomials of different degrees were used to refine the cell fate prediction function. 10-fold cross-validation was carried out to evaluate the performance of our model. In addition, we analyzed the stability of the resultant cell fate prediction model by evaluating the ranges of the parameters, as well as assessing the variances of the predicted values at randomly selected points. Results show that, within both the two considered gene selection methods, the prediction accuracies of polynomials of different degrees show little differences. Interestingly, the linear polynomial (degree 1 polynomial) is more stable than others. When comparing the linear polynomials based on the two gene selection methods, it shows that although the accuracy of the linear polynomial that uses correlation analysis outcomes is a little higher (achieves 86.62%), the one within genes of the apoptosis pathway is much more stable. Considering both the prediction accuracy and the stability of polynomial models of different degrees, the linear model is a preferred choice for cell fate prediction with gene expression data of pancreatic cells. The presented cell fate prediction model can be extended to other cells, which may be important for basic research as well as clinical study of cell development related diseases.

  11. Notch signaling in bulge stem cells is not required for selection of hair follicle fate

    Science.gov (United States)

    Demehri, Shadmehr; Kopan, Raphael

    2009-01-01

    Summary Notch signaling plays an important role in hair follicle maintenance, and it has been suggested that Notch is also required for follicular fate selection by adult hair follicle stem cells in the bulge. Here we demonstrate that, on the contrary, Notch signaling in bi-potential bulge stem cells or their uncommitted descendents acts to suppress the epidermal fate choice, thus ensuring follicular fate selection. To examine the role of Notch signaling in adult hair follicle stem cells, we used a Krt1-15-CrePR1 transgenic mouse line to delete Rbpj or all Notch proteins specifically in the bulge stem cells. We conclusively determined that in the absence of Notch signaling, bulge stem cell descendents retain their capacity to execute the follicular differentiation program but fail to maintain it owing to their genetic deficiency. The defect in terminal differentiation caused the diversion of Notch-deficient hair follicles to epidermal cysts, and the presence of wild-type cells could not prevent this conversion. Importantly, our analysis revealed that a functional Notch signaling pathway was required to block bulge stem cells from migrating into, and assuming the fate of, interfollicular epidermis. Taken together, our findings yield detailed insight into the function of Notch signaling in hair follicle stem cells and reveal the mechanism of the replacement of Notch-deficient adult hair follicles by epidermal cysts. PMID:19211676

  12. Epigenetic memory and cell fate reprogramming in plants.

    Science.gov (United States)

    Birnbaum, Kenneth D; Roudier, François

    2017-02-01

    Plants have a high intrinsic capacity to regenerate from adult tissues, with the ability to reprogram adult cell fates. In contrast, epigenetic mechanisms have the potential to stabilize cell identity and maintain tissue organization. The question is whether epigenetic memory creates a barrier to reprogramming that needs to be erased or circumvented in plant regeneration. Early evidence suggests that, while chromatin dynamics impact gene expression in the meristem, a lasting constraint on cell fate is not established until late stages of plant cell differentiation. It is not yet clear whether the plasticity of plant cells arises from the ability of cells to erase identity memory or to deploy cells that may exhibit cellular specialization but still lack an epigenetic restriction on cell fate alteration.

  13. Identifying gene expression modules that define human cell fates.

    Science.gov (United States)

    Germanguz, I; Listgarten, J; Cinkornpumin, J; Solomon, A; Gaeta, X; Lowry, W E

    2016-05-01

    Using a compendium of cell-state-specific gene expression data, we identified genes that uniquely define cell states, including those thought to represent various developmental stages. Our analysis sheds light on human cell fate through the identification of core genes that are altered over several developmental milestones, and across regional specification. Here we present cell-type specific gene expression data for 17 distinct cell states and demonstrate that these modules of genes can in fact define cell fate. Lastly, we introduce a web-based database to disseminate the results. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  14. A deterministic map of Waddington's epigenetic landscape for cell fate specification

    Science.gov (United States)

    2011-01-01

    Background The image of the "epigenetic landscape", with a series of branching valleys and ridges depicting stable cellular states and the barriers between those states, has been a popular visual metaphor for cell lineage specification - especially in light of the recent discovery that terminally differentiated adult cells can be reprogrammed into pluripotent stem cells or into alternative cell lineages. However the question of whether the epigenetic landscape can be mapped out quantitatively to provide a predictive model of cellular differentiation remains largely unanswered. Results Here we derive a simple deterministic path-integral quasi-potential, based on the kinetic parameters of a gene network regulating cell fate, and show that this quantity is minimized along a temporal trajectory in the state space of the gene network, thus providing a marker of directionality for cell differentiation processes. We then use the derived quasi-potential as a measure of "elevation" to quantitatively map the epigenetic landscape, on which trajectories flow "downhill" from any location. Stochastic simulations confirm that the elevation of this computed landscape correlates to the likelihood of occurrence of particular cell fates, with well-populated low-lying "valleys" representing stable cellular states and higher "ridges" acting as barriers to transitions between the stable states. Conclusions This quantitative map of the epigenetic landscape underlying cell fate choice provides mechanistic insights into the "forces" that direct cellular differentiation in the context of physiological development, as well as during artificially induced cell lineage reprogramming. Our generalized approach to mapping the landscape is applicable to non-gradient gene regulatory systems for which an analytical potential function cannot be derived, and also to high-dimensional gene networks. Rigorous quantification of the gene regulatory circuits that govern cell lineage choice and subsequent

  15. A Feed-Forward Regulation Sets Cell Fates in Roots.

    Science.gov (United States)

    Berckmans, Barbara; Simon, Rüdiger

    2016-05-01

    Formative cell divisions generate new cell types and tissues during development, and are controlled by receptor kinase signalling pathways. The phosphatase PP2A has now been shown to be both a target and positive regulator of the receptor kinase ACR4, thus creating a feed-forward loop that serves to establish new cell fates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Specification of Epidermal Cell Fate in Plant Shoots

    Directory of Open Access Journals (Sweden)

    Shinobu eTakada

    2014-02-01

    Full Text Available Land plants have evolved a single layer of epidermal cells, which are characterized by mostly anticlinal cell division patterns, formation of a waterproof coat called cuticle, and unique cell types such as stomatal guard cells and trichomes. The shoot epidermis plays important roles not only to protect plants from dehydration and pathogens but also to ensure their proper organogenesis and growth control. Extensive molecular genetic studies in Arabidopsis and maize have identified a number of genes that are required for epidermal cell differentiation. However, the mechanism that specifies shoot epidermal cell fate during plant organogenesis remains largely unknown. Particularly, little is known regarding positional information that should restrict epidermal cell fate to the outermost cell layer of the developing organs. Recent studies suggested that certain members of the HD-ZIP class IV homeobox genes are possible master regulators of shoot epidermal cell fate. Here, we summarize the roles of the regulatory genes that are involved in epidermal cell fate specification and discuss the possible mechanisms that limit the expression and/or activity of the master transcriptional regulators to the outermost cell layer in plant shoots.

  17. Notch signaling in the pancreas: patterning and cell fate specification.

    Science.gov (United States)

    Afelik, Solomon; Jensen, Jan

    2013-07-01

    Notch signaling is an evolutionarily conserved mechanism adapted to control binary fate decisions. The first evidence of Notch in pancreatic development focused on its critical role in controlling endocrine fate decisions. Since then, we have come to understand that this signaling system operates iteratively in the pancreas, and is not limited to the control of endocrine fate decision. Notch appears to play a role in early organ development, then during organ domain patterning, and only during a final refinement process, in the control of terminal cell fates. In so doing, Notch receptors and their ligands are under the influence of a wealth of genetic components that together help orchestrate the building of a complex, glandular organ. Copyright © 2012 Wiley Periodicals, Inc.

  18. Identifying gene expression modules that define human cell fates

    OpenAIRE

    Germanguz, I; Listgarten, J; Cinkornpumin, J.; Solomon, A; Gaeta, X.; Lowry, W. E.

    2016-01-01

    Using a compendium of cell-state-specific gene expression data, we identified genes that uniquely define cell states, including those thought to represent various developmental stages. Our analysis sheds light on human cell fate through the identification of core genes that are altered over several developmental milestones, and across regional specification. Here we present cell-type specific gene expression data for 17 distinct cell states and demonstrate that these modules of genes can in f...

  19. Multiscale microenvironmental perturbation of pluripotent stem cell fate and self-organization

    Science.gov (United States)

    Tabata, Yoji; Lutolf, Matthias P.

    2017-03-01

    The combination of microfluidics with engineered three-dimensional (3D) matrices can bring new insights into the fate regulation of stem cells and their self-organization into organoids. Although there has been progress in 3D stem cell culturing, most existing in vitro methodologies do not allow for mimicking of the spatiotemporal heterogeneity of stimuli that drive morphogenetic processes in vivo. To address this, we present a perfusion-free microchip concept for the in vitro 3D perturbation of stem cell fate. Stem cells are encapsulated in a hydrogel compartment that is flanked by open reservoirs for the diffusion-driven generation of biomolecule gradients. Juxtaposing additional compartments bearing supportive cells enables investigating the influence of long range cell-cell communication. We explore the utility of the microchips in manipulating early fate choices and self-organizing characteristics of 3D-cultured mouse embryonic stem cells (mESCs) under neural differentiation conditions and exposure to gradients of leukemia inhibitory factor (LIF). mESCs respond to LIF gradients in a spatially dependent manner. At higher LIF concentrations, multicellular colonies maintain pluripotency in contrast, at lower concentrations, mESCs develop into apicobasally polarized epithelial cysts. This versatile system can help to systematically explore the role of multifactorial microenvironments in promoting self-patterning of various stem cell types.

  20. Divergence of zebrafish and mouse lymphatic cell fate specification pathways

    NARCIS (Netherlands)

    van Impel, Andreas; Zhao, Zhonghua; Hermkens, Dorien M A; Roukens, M Guy; Fischer, Johanna C; Peterson-Maduro, Josi; Duckers, Henricus; Ober, Elke A; Ingham, Philip W; Schulte-Merker, Stefan

    In mammals, the homeodomain transcription factor Prox1 acts as the central regulator of lymphatic cell fate. Its restricted expression in a subset of cardinal vein cells leads to a switch towards lymphatic specification and hence represents a prerequisite for the initiation of lymphangiogenesis.

  1. Cell fate determination in zebrafish embryonic and adult muscle development

    NARCIS (Netherlands)

    Tee, J.M.

    2010-01-01

    We are interested in how the genetic basis of muscle precursor cells determines the outcome of the muscle cell fate, and thus leading to disruption in muscle formation and maintenance. We utilized the zebrafish carrying mutations in both Axin1 and Apc1, resulting in overactivation of the

  2. Cdc20 control of cell fate during prolonged mitotic arrest

    DEFF Research Database (Denmark)

    Nilsson, Jakob

    2011-01-01

    The fate of cells arrested in mitosis by antimitotic compounds is complex but is influenced by competition between pathways promoting cell death and pathways promoting mitotic exit. As components of both of these pathways are regulated by Cdc20-dependent degradation, I hypothesize that variations...

  3. FY08 LDRD Final Report Stem Cell Fate Decisions

    Energy Technology Data Exchange (ETDEWEB)

    Hiddessen, A

    2009-03-02

    A detailed understanding of the biological control of fate decisions of stem and progenitor cells is needed to harness their full power for tissue repair and/or regeneration. Currently, internal and external factors that regulate stem cell fate are not fully understood. We aim to engineer biocompatible tools to facilitate the measurement and comparison of the roles and significance of immobilized factors such as extracellular matrix and signaling peptides, synergistic and opposing soluble factors and signals, and cell-to-cell communication, in stem cell fate decisions. Our approach is based on the development of cell microarrays to capture viable stem/progenitor cells individually or in small clusters onto substrate-bound signals (e.g. proteins), combined with conventional antibody and customized subcellular markers made in-house, to facilitate tracking of cell behavior during exposure to relevant signals. Below we describe our efforts, including methods to manipulate a model epithelial stem cell system using a custom subcellular reporter to track and measure cell signaling, arrays with surface chemistry that support viable cells and enable controlled presentation of immobilized signals to cells on the array and fluorescence-based measurement of cell response, and successful on-array tests via conventional immunofluorescence assays that indicate correct cell polarity, localization of junctional proteins, and phenotype, properties which are essential to measuring true cell responses.

  4. Nox, Reactive Oxygen Species and Regulation of Vascular Cell Fate

    Directory of Open Access Journals (Sweden)

    Denise Burtenshaw

    2017-11-01

    Full Text Available The generation of reactive oxygen species (ROS and an imbalance of antioxidant defence mechanisms can result in oxidative stress. Several pro-atherogenic stimuli that promote intimal-medial thickening (IMT and early arteriosclerotic disease progression share oxidative stress as a common regulatory pathway dictating vascular cell fate. The major source of ROS generated within the vascular system is the nicotinamide adenine dinucleotide phosphate (NADPH oxidase family of enzymes (Nox, of which seven members have been characterized. The Nox family are critical determinants of the redox state within the vessel wall that dictate, in part the pathophysiology of several vascular phenotypes. This review highlights the putative role of ROS in controlling vascular fate by promoting endothelial dysfunction, altering vascular smooth muscle phenotype and dictating resident vascular stem cell fate, all of which contribute to intimal medial thickening and vascular disease progression.

  5. Distinct interactions select and maintain a specific cell fate.

    Science.gov (United States)

    Doncic, Andreas; Falleur-Fettig, Melody; Skotheim, Jan M

    2011-08-19

    The ability to specify and maintain discrete cell fates is essential for development. However, the dynamics underlying selection and stability of distinct cell types remain poorly understood. Here, we provide a quantitative single-cell analysis of commitment dynamics during the mating-mitosis switch in budding yeast. Commitment to division corresponds precisely to activating the G1 cyclin positive feedback loop in competition with the cyclin inhibitor Far1. Cyclin-dependent phosphorylation and inhibition of the mating pathway scaffold Ste5 are required to ensure exclusive expression of the mitotic transcriptional program after cell cycle commitment. Failure to commit exclusively results in coexpression of both cell cycle and pheromone-induced genes, and a morphologically mixed inviable cell fate. Thus, specification and maintenance of a cellular state are performed by distinct interactions, which are likely a consequence of disparate reaction rates and may be a general feature of the interlinked regulatory networks responsible for selecting cell fates. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Cell fate determination during tooth development and regeneration.

    Science.gov (United States)

    Mitsiadis, Thimios A; Graf, Daniel

    2009-09-01

    Teeth arise from sequential and reciprocal interactions between the oral epithelium and the underlying cranial neural crest-derived mesenchyme. Their formation involves a precisely orchestrated series of molecular and morphogenetic events, and gives us the opportunity to discover and understand the nature of the signals that direct cell fates and patterning. For that reason, it is important to elucidate how signaling factors work together in a defined number of cells to generate the diverse and precise patterned structures of the mature functional teeth. Over the last decade, substantial research efforts have been directed toward elucidating the molecular mechanisms that control cell fate decisions during tooth development. These efforts have contributed toward the increased knowledge on dental stem cells, and observation of the molecular similarities that exist between tooth development and regeneration.

  7. Magnetic resonance imaging of transplanted stem cell fate in stroke

    OpenAIRE

    Hamid Reza Aghayan; Masoud Soleimani; Parisa Goodarzi; Abbas Norouzi-Javidan; Seyed Hasan Emami-Razavi; Bagher Larijani; Babak Arjmand

    2014-01-01

    Nowadays, scientific findings in the field of regeneration of nervous system have revealed the possibility of stem cell based therapies for damaged brain tissue related disorders like stroke. Furthermore, to achieve desirable outcomes from cellular therapies, one needs to monitor the migration, engraftment, viability, and also functional fate of transplanted stem cells. Magnetic resonance imaging is an extremely versatile technique for this purpose, which has been broadly used to study stroke...

  8. The Advancement of Biomaterials in Regulating Stem Cell Fate.

    Science.gov (United States)

    Hiew, Vun Vun; Simat, Siti Fatimah Binti; Teoh, Peik Lin

    2017-09-07

    Stem cells are well-known to have prominent roles in tissue engineering applications. Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) can differentiate into every cell type in the body while adult stem cells such as mesenchymal stem cells (MSCs) can be isolated from various sources. Nevertheless, an utmost limitation in harnessing stem cells for tissue engineering is the supply of cells. The advances in biomaterial technology allows the establishment of ex vivo expansion systems to overcome this bottleneck. The progress of various scaffold fabrication could direct stem cell fate decisions including cell proliferation and differentiation into specific lineages in vitro. Stem cell biology and biomaterial technology promote synergistic effect on stem cell-based regenerative therapies. Therefore, understanding the interaction of stem cell and biomaterials would allow the designation of new biomaterials for future clinical therapeutic applications for tissue regeneration. This review focuses mainly on the advances of natural and synthetic biomaterials in regulating stem cell fate decisions. We have also briefly discussed how biological and biophysical properties of biomaterials including wettability, chemical functionality, biodegradability and stiffness play their roles.

  9. Epigenetic control of embryonic stem cell fate

    DEFF Research Database (Denmark)

    Christophersen, Nicolaj Strøyer; Helin, Kristian

    2010-01-01

    Embryonic stem (ES) cells are derived from the inner cell mass of the preimplantation embryo and are pluripotent, as they are able to differentiate into all cell types of the adult organism. Once established, the pluripotent ES cells can be maintained under defined culture conditions, but can also...... be induced rapidly to differentiate. Maintaining this balance of stability versus plasticity is a challenge, and extensive studies in recent years have focused on understanding the contributions of transcription factors and epigenetic enzymes to the "stemness" properties of these cells. Identifying...... the molecular switches that regulate ES cell self-renewal versus differentiation can provide insights into the nature of the pluripotent state and enhance the potential use of these cells in therapeutic applications. Here, we review the latest models for how changes in chromatin methylation can modulate ES cell...

  10. Eat, breathe, ROS: controlling stem cell fate through metabolism.

    Science.gov (United States)

    Kubli, Dieter A; Sussman, Mark A

    2017-05-01

    Research reveals cardiac regeneration exists at levels previously deemed unattainable. Clinical trials using stem cells demonstrate promising cardiomyogenic and regenerative potential but insufficient contractile recovery. Incomplete understanding of the biology of administered cells likely contributes to inconsistent patient outcomes. Metabolism is a core component of many well-characterized stem cell types, and metabolic changes fundamentally alter stem cell fate from self-renewal to lineage commitment, and vice versa. However, the metabolism of stem cells currently studied for cardiac regeneration remains incompletely understood. Areas covered: Key metabolic features of stem cells are reviewed and unique stem cell metabolic characteristics are discussed. Metabolic changes altering stem cell fate are considered from quiescence and self-renewal to lineage commitment. Key metabolic concepts are applied toward examining cardiac regeneration through stem cell-based approaches, and clinical implications of current cell therapies are evaluated to identify potential areas of improvement. Expert commentary: The metabolism and biology of stem cells used for cardiac therapy remain poorly characterized. A growing appreciation for the fundamental relationship between stem cell functionality and metabolic phenotype is developing. Future studies unraveling links between cardiac stem cell metabolism and regenerative potential may considerably improve treatment strategies and therapeutic outcomes.

  11. gammadelta and alphabeta T cell lineage choice: resolution by a stronger sense of being.

    Science.gov (United States)

    Wong, Gladys W; Zúñiga-Pflücker, Juan Carlos

    2010-08-01

    A common bipotent thymocyte precursor gives rise to both lineages of T cells, alphabeta and gammadelta. However, the cell intrinsic and extrinsic factors that influence alphabeta- versus gammadelta-lineage bifurcation remain controversial. gammadelta T cells play a unique and vital role in host defense, from maintaining integrity at epithelial and mucosal barriers to their newly defined role as an important innate source of interleukin-17. Although a T cell receptor (TCR)-independent fate choice may take place, emerging data supports a model in which the differential signaling capacity of alphabeta and gammadeltaTCRs play an instructional role in specifying lineage fate, with strength of signal measured by the amount of ERK/MAPK pathway activation. Here we discuss how the interplay between intrinsic TCR signals and cell extrinsic signals provided by Notch and TCR ligands help to assign and support a final lineage fate decision. 2010 Elsevier Ltd. All rights reserved.

  12. Polylox barcoding reveals haematopoietic stem cell fates realized in vivo.

    Science.gov (United States)

    Pei, Weike; Feyerabend, Thorsten B; Rössler, Jens; Wang, Xi; Postrach, Daniel; Busch, Katrin; Rode, Immanuel; Klapproth, Kay; Dietlein, Nikolaus; Quedenau, Claudia; Chen, Wei; Sauer, Sascha; Wolf, Stephan; Höfer, Thomas; Rodewald, Hans-Reimer

    2017-08-24

    Developmental deconvolution of complex organs and tissues at the level of individual cells remains challenging. Non-invasive genetic fate mapping has been widely used, but the low number of distinct fluorescent marker proteins limits its resolution. Much higher numbers of cell markers have been generated using viral integration sites, viral barcodes, and strategies based on transposons and CRISPR-Cas9 genome editing; however, temporal and tissue-specific induction of barcodes in situ has not been achieved. Here we report the development of an artificial DNA recombination locus (termed Polylox) that enables broadly applicable endogenous barcoding based on the Cre-loxP recombination system. Polylox recombination in situ reaches a practical diversity of several hundred thousand barcodes, allowing tagging of single cells. We have used this experimental system, combined with fate mapping, to assess haematopoietic stem cell (HSC) fates in vivo. Classical models of haematopoietic lineage specification assume a tree with few major branches. More recently, driven in part by the development of more efficient single-cell assays and improved transplantation efficiencies, different models have been proposed, in which unilineage priming may occur in mice and humans at the level of HSCs. We have introduced barcodes into HSC progenitors in embryonic mice, and found that the adult HSC compartment is a mosaic of embryo-derived HSC clones, some of which are unexpectedly large. Most HSC clones gave rise to multilineage or oligolineage fates, arguing against unilineage priming, and suggesting coherent usage of the potential of cells in a clone. The spreading of barcodes, both after induction in embryos and in adult mice, revealed a basic split between common myeloid-erythroid development and common lymphocyte development, supporting the long-held but contested view of a tree-like haematopoietic structure.

  13. An interplay between extracellular signalling and the dynamics of the exit from pluripotency drives cell fate decisions in mouse ES cells

    Directory of Open Access Journals (Sweden)

    David A. Turner

    2014-06-01

    Full Text Available Embryonic Stem cells derived from the epiblast tissue of the mammalian blastocyst retain the capability to differentiate into any adult cell type and are able to self-renew indefinitely under appropriate culture conditions. Despite the large amount of knowledge that we have accumulated to date about the regulation and control of self-renewal, efficient directed differentiation into specific tissues remains elusive. In this work, we have analysed in a systematic manner the interaction between the dynamics of loss of pluripotency and Activin/Nodal, BMP4 and Wnt signalling in fate assignment during the early stages of differentiation of mouse ES cells in culture. During the initial period of differentiation, cells exit from pluripotency and enter an Epi-like state. Following this transient stage, and under the influence of Activin/Nodal and BMP signalling, cells face a fate choice between differentiating into neuroectoderm and contributing to Primitive Streak fates. We find that Wnt signalling does not suppress neural development as previously thought and that it aids both fates in a context dependent manner. Our results suggest that as cells exit pluripotency they are endowed with a primary neuroectodermal fate and that the potency to become endomesodermal rises with time. We suggest that this situation translates into a “race for fates” in which the neuroectodermal fate has an advantage.

  14. An interplay between extracellular signalling and the dynamics of the exit from pluripotency drives cell fate decisions in mouse ES cells

    Science.gov (United States)

    Turner, David A.; Trott, Jamie; Hayward, Penelope; Rué, Pau; Martinez Arias, Alfonso

    2014-01-01

    ABSTRACT Embryonic Stem cells derived from the epiblast tissue of the mammalian blastocyst retain the capability to differentiate into any adult cell type and are able to self-renew indefinitely under appropriate culture conditions. Despite the large amount of knowledge that we have accumulated to date about the regulation and control of self-renewal, efficient directed differentiation into specific tissues remains elusive. In this work, we have analysed in a systematic manner the interaction between the dynamics of loss of pluripotency and Activin/Nodal, BMP4 and Wnt signalling in fate assignment during the early stages of differentiation of mouse ES cells in culture. During the initial period of differentiation, cells exit from pluripotency and enter an Epi-like state. Following this transient stage, and under the influence of Activin/Nodal and BMP signalling, cells face a fate choice between differentiating into neuroectoderm and contributing to Primitive Streak fates. We find that Wnt signalling does not suppress neural development as previously thought and that it aids both fates in a context dependent manner. Our results suggest that as cells exit pluripotency they are endowed with a primary neuroectodermal fate and that the potency to become endomesodermal rises with time. We suggest that this situation translates into a “race for fates” in which the neuroectodermal fate has an advantage. PMID:24950969

  15. Hedgehog and Resident Vascular Stem Cell Fate

    Directory of Open Access Journals (Sweden)

    Ciaran J. Mooney

    2015-01-01

    Full Text Available The Hedgehog pathway is a pivotal morphogenic driver during embryonic development and a key regulator of adult stem cell self-renewal. The discovery of resident multipotent vascular stem cells and adventitial progenitors within the vessel wall has transformed our understanding of the origin of medial and neointimal vascular smooth muscle cells (SMCs during vessel repair in response to injury, lesion formation, and overall disease progression. This review highlights the importance of components of the Hh and Notch signalling pathways within the medial and adventitial regions of adult vessels, their recapitulation following vascular injury and disease progression, and their putative role in the maintenance and differentiation of resident vascular stem cells to vascular lineages from discrete niches within the vessel wall.

  16. Atypical chemokine receptor 4 shapes activated B cell fate.

    Science.gov (United States)

    Kara, Ervin E; Bastow, Cameron R; McKenzie, Duncan R; Gregor, Carly E; Fenix, Kevin A; Babb, Rachelle; Norton, Todd S; Zotos, Dimitra; Rodda, Lauren B; Hermes, Jana R; Bourne, Katherine; Gilchrist, Derek S; Nibbs, Robert J; Alsharifi, Mohammed; Vinuesa, Carola G; Tarlinton, David M; Brink, Robert; Hill, Geoffrey R; Cyster, Jason G; Comerford, Iain; McColl, Shaun R

    2018-01-31

    Activated B cells can initially differentiate into three functionally distinct fates-early plasmablasts (PBs), germinal center (GC) B cells, or early memory B cells-by mechanisms that remain poorly understood. Here, we identify atypical chemokine receptor 4 (ACKR4), a decoy receptor that binds and degrades CCR7 ligands CCL19/CCL21, as a regulator of early activated B cell differentiation. By restricting initial access to splenic interfollicular zones (IFZs), ACKR4 limits the early proliferation of activated B cells, reducing the numbers available for subsequent differentiation. Consequently, ACKR4 deficiency enhanced early PB and GC B cell responses in a CCL19/CCL21-dependent and B cell-intrinsic manner. Conversely, aberrant localization of ACKR4-deficient activated B cells to the IFZ was associated with their preferential commitment to the early PB linage. Our results reveal a regulatory mechanism of B cell trafficking via an atypical chemokine receptor that shapes activated B cell fate. © 2018 Kara et al.

  17. Morphogenesis and cell fate determination within the adaxial cell equivalence group of the zebrafish myotome.

    Directory of Open Access Journals (Sweden)

    Mai E Nguyen-Chi

    Full Text Available One of the central questions of developmental biology is how cells of equivalent potential-an equivalence group-come to adopt specific cellular fates. In this study we have used a combination of live imaging, single cell lineage analyses, and perturbation of specific signaling pathways to dissect the specification of the adaxial cells of the zebrafish embryo. We show that the adaxial cells are myogenic precursors that form a cell fate equivalence group of approximately 20 cells that consequently give rise to two distinct sub-types of muscle fibers: the superficial slow muscle fibers (SSFs and muscle pioneer cells (MPs, distinguished by specific gene expression and cell behaviors. Using a combination of live imaging, retrospective and indicative fate mapping, and genetic studies, we show that MP and SSF precursors segregate at the beginning of segmentation and that they arise from distinct regions along the anterior-posterior (AP and dorsal-ventral (DV axes of the adaxial cell compartment. FGF signaling restricts MP cell fate in the anterior-most adaxial cells in each somite, while BMP signaling restricts this fate to the middle of the DV axis. Thus our results reveal that the synergistic actions of HH, FGF, and BMP signaling independently create a three-dimensional (3D signaling milieu that coordinates cell fate within the adaxial cell equivalence group.

  18. Morphogenesis and Cell Fate Determination within the Adaxial Cell Equivalence Group of the Zebrafish Myotome

    Science.gov (United States)

    Nguyen-Chi, Mai E.; Bryson-Richardson, Robert; Sonntag, Carmen; Hall, Thomas E.; Gibson, Abigail; Sztal, Tamar; Chua, Wendy; Schilling, Thomas F.; Currie, Peter D.

    2012-01-01

    One of the central questions of developmental biology is how cells of equivalent potential—an equivalence group—come to adopt specific cellular fates. In this study we have used a combination of live imaging, single cell lineage analyses, and perturbation of specific signaling pathways to dissect the specification of the adaxial cells of the zebrafish embryo. We show that the adaxial cells are myogenic precursors that form a cell fate equivalence group of approximately 20 cells that consequently give rise to two distinct sub-types of muscle fibers: the superficial slow muscle fibers (SSFs) and muscle pioneer cells (MPs), distinguished by specific gene expression and cell behaviors. Using a combination of live imaging, retrospective and indicative fate mapping, and genetic studies, we show that MP and SSF precursors segregate at the beginning of segmentation and that they arise from distinct regions along the anterior-posterior (AP) and dorsal-ventral (DV) axes of the adaxial cell compartment. FGF signaling restricts MP cell fate in the anterior-most adaxial cells in each somite, while BMP signaling restricts this fate to the middle of the DV axis. Thus our results reveal that the synergistic actions of HH, FGF, and BMP signaling independently create a three-dimensional (3D) signaling milieu that coordinates cell fate within the adaxial cell equivalence group. PMID:23133395

  19. Multicolor fate mapping of langerhans cell homeostasis

    NARCIS (Netherlands)

    E. Ghigo (Ezio); I. Mondor (Isabelle); A. Jorquera (Audrey); N. Nowak (NowakJonathan); S. Wienert (Stephan); S.P. Zahner (Sonja P.); B.E. Clausen (Bjorn); H. Luche (Hervé); B. Malissen (Bernard); F. Klauschen (Frederick); M. Bajénoff (Marc)

    2013-01-01

    textabstractLangerhans cells (LCs) constitute a network of immune sentinels in the skin epidermis that is seeded during embryogenesis. Whereas the development of LCs has been extensively studied, much less is known about the homeostatic renewal of adult LCs in "nonmanipulated" animals. Here, we

  20. LACHESIS restricts gametic cell fate in the female gametophyte of Arabidopsis.

    Directory of Open Access Journals (Sweden)

    Rita Gross-Hardt

    2007-03-01

    Full Text Available In flowering plants, the egg and sperm cells form within haploid gametophytes. The female gametophyte of Arabidopsis consists of two gametic cells, the egg cell and the central cell, which are flanked by five accessory cells. Both gametic and accessory cells are vital for fertilization; however, the mechanisms that underlie the formation of accessory versus gametic cell fate are unknown. In a screen for regulators of egg cell fate, we isolated the lachesis (lis mutant which forms supernumerary egg cells. In lis mutants, accessory cells differentiate gametic cell fate, indicating that LIS is involved in a mechanism that prevents accessory cells from adopting gametic cell fate. The temporal and spatial pattern of LIS expression suggests that this mechanism is generated in gametic cells. LIS is homologous to the yeast splicing factor PRP4, indicating that components of the splice apparatus participate in cell fate decisions.

  1. An Empirically Calibrated Model of Cell Fate Decision Following Viral Infection

    Science.gov (United States)

    Coleman, Seth; Igoshin, Oleg; Golding, Ido

    The life cycle of the virus (phage) lambda is an established paradigm for the way genetic networks drive cell fate decisions. But despite decades of interrogation, we are still unable to theoretically predict whether the infection of a given cell will result in cell death or viral dormancy. The poor predictive power of current models reflects the absence of quantitative experimental data describing the regulatory interactions between different lambda genes. To address this gap, we are constructing a theoretical model that captures the known interactions in the lambda network. Model assumptions and parameters are calibrated using new single-cell data from our lab, describing the activity of lambda genes at single-molecule resolution. We began with a mean-field model, aimed at exploring the population averaged gene-expression trajectories under different initial conditions. Next, we will develop a stochastic formulation, to capture the differences between individual cells within the population. The eventual goal is to identify how the post-infection decision is driven by the interplay between network topology, initial conditions, and stochastic effects. The insights gained here will inform our understanding of cell fate choices in more complex cellular systems.

  2. Nuclear envelope and genome interactions in cell fate

    Science.gov (United States)

    Talamas, Jessica A.; Capelson, Maya

    2015-01-01

    The eukaryotic cell nucleus houses an organism’s genome and is the location within the cell where all signaling induced and development-driven gene expression programs are ultimately specified. The genome is enclosed and separated from the cytoplasm by the nuclear envelope (NE), a double-lipid membrane bilayer, which contains a large variety of trans-membrane and associated protein complexes. In recent years, research regarding multiple aspects of the cell nucleus points to a highly dynamic and coordinated concert of efforts between chromatin and the NE in regulation of gene expression. Details of how this concert is orchestrated and how it directs cell differentiation and disease are coming to light at a rapid pace. Here we review existing and emerging concepts of how interactions between the genome and the NE may contribute to tissue specific gene expression programs to determine cell fate. PMID:25852741

  3. Twist1 Controls a Cell-Specification Switch Governing Cell Fate Decisions within the Cardiac Neural Crest

    Science.gov (United States)

    Vincentz, Joshua W.; Firulli, Beth A.; Lin, Andrea; Spicer, Douglas B.; Howard, Marthe J.; Firulli, Anthony B.

    2013-01-01

    Neural crest cells are multipotent progenitor cells that can generate both ectodermal cell types, such as neurons, and mesodermal cell types, such as smooth muscle. The mechanisms controlling this cell fate choice are not known. The basic Helix-loop-Helix (bHLH) transcription factor Twist1 is expressed throughout the migratory and post-migratory cardiac neural crest. Twist1 ablation or mutation of the Twist-box causes differentiation of ectopic neuronal cells, which molecularly resemble sympathetic ganglia, in the cardiac outflow tract. Twist1 interacts with the pro-neural factor Sox10 via its Twist-box domain and binds to the Phox2b promoter to repress transcriptional activity. Mesodermal cardiac neural crest trans-differentiation into ectodermal sympathetic ganglia-like neurons is dependent upon Phox2b function. Ectopic Twist1 expression in neural crest precursors disrupts sympathetic neurogenesis. These data demonstrate that Twist1 functions in post-migratory neural crest cells to repress pro-neural factors and thereby regulate cell fate determination between ectodermal and mesodermal lineages. PMID:23555309

  4. Control of Cell Fate in the Circulatory and Ventilatory Systems

    CERN Document Server

    Thiriet, Marc

    2012-01-01

    The volumes in this authoritative series present a multidisciplinary approach to modeling and simulation of flows in the cardiovascular and ventilatory systems, especially multiscale modeling and coupled simulations. The cardiovascular and respiratory systems are tightly coupled, as their primary function is to supply oxygen to and remove carbon dioxide from the body's cells. Because physiological conduits have deformable and reactive walls, macroscopic flow behavior and prediction must be coupled to nano- and microscopic events in a corrector scheme of regulated mechanisms. Therefore, investigation of flows of blood and air in physiological conduits requires an understanding of the biology, chemistry, and physics of these systems together with the mathematical tools to describe their functioning. Volumes 1 and 2 are devoted to cell organization and fate, as well as activities that are autoregulated and/or controlled by the cell environment. Volume 1 examined cellular features that allow adaptation to env...

  5. The Unfolded Protein Response and Cell Fate Control.

    Science.gov (United States)

    Hetz, Claudio; Papa, Feroz R

    2017-10-25

    The secretory capacity of a cell is constantly challenged by physiological demands and pathological perturbations. To adjust and match the protein-folding capacity of the endoplasmic reticulum (ER) to changing secretory needs, cells employ a dynamic intracellular signaling pathway known as the unfolded protein response (UPR). Homeostatic activation of the UPR enforces adaptive programs that modulate and augment key aspects of the entire secretory pathway, whereas maladaptive UPR outputs trigger apoptosis. Here, we discuss recent advances into how the UPR integrates information about the intensity and duration of ER stress stimuli in order to control cell fate. These findings are timely and significant because they inform an evolving mechanistic understanding of a wide variety of human diseases, including diabetes mellitus, neurodegeneration, and cancer, thus opening up the potential for new therapeutic modalities to treat these diverse diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Dynamic transcriptional signature and cell fate analysis reveals plasticity of individual neural plate border cells.

    Science.gov (United States)

    Roellig, Daniela; Tan-Cabugao, Johanna; Esaian, Sevan; Bronner, Marianne E

    2017-03-29

    The 'neural plate border' of vertebrate embryos contains precursors of neural crest and placode cells, both defining vertebrate characteristics. How these lineages segregate from neural and epidermal fates has been a matter of debate. We address this by performing a fine-scale quantitative temporal analysis of transcription factor expression in the neural plate border of chick embryos. The results reveal significant overlap of transcription factors characteristic of multiple lineages in individual border cells from gastrula through neurula stages. Cell fate analysis using a Sox2 (neural) enhancer reveals that cells that are initially Sox2+ cells can contribute not only to neural tube but also to neural crest and epidermis. Moreover, modulating levels of Sox2 or Pax7 alters the apportionment of neural tube versus neural crest fates. Our results resolve a long-standing question and suggest that many individual border cells maintain ability to contribute to multiple ectodermal lineages until or beyond neural tube closure.

  7. Reprogramming cell fate with a genome-scale library of artificial transcription factors.

    Science.gov (United States)

    Eguchi, Asuka; Wleklinski, Matthew J; Spurgat, Mackenzie C; Heiderscheit, Evan A; Kropornicka, Anna S; Vu, Catherine K; Bhimsaria, Devesh; Swanson, Scott A; Stewart, Ron; Ramanathan, Parameswaran; Kamp, Timothy J; Slukvin, Igor; Thomson, James A; Dutton, James R; Ansari, Aseem Z

    2016-12-20

    Artificial transcription factors (ATFs) are precision-tailored molecules designed to bind DNA and regulate transcription in a preprogrammed manner. Libraries of ATFs enable the high-throughput screening of gene networks that trigger cell fate decisions or phenotypic changes. We developed a genome-scale library of ATFs that display an engineered interaction domain (ID) to enable cooperative assembly and synergistic gene expression at targeted sites. We used this ATF library to screen for key regulators of the pluripotency network and discovered three combinations of ATFs capable of inducing pluripotency without exogenous expression of Oct4 (POU domain, class 5, TF 1). Cognate site identification, global transcriptional profiling, and identification of ATF binding sites reveal that the ATFs do not directly target Oct4; instead, they target distinct nodes that converge to stimulate the endogenous pluripotency network. This forward genetic approach enables cell type conversions without a priori knowledge of potential key regulators and reveals unanticipated gene network dynamics that drive cell fate choices.

  8. Muscle Stem Cell Fate Is Controlled by the Cell-Polarity Protein Scrib

    Directory of Open Access Journals (Sweden)

    Yusuke Ono

    2015-02-01

    Full Text Available Satellite cells are resident skeletal muscle stem cells that supply myonuclei for homeostasis, hypertrophy, and repair in adult muscle. Scrib is one of the major cell-polarity proteins, acting as a potent tumor suppressor in epithelial cells. Here, we show that Scrib also controls satellite-cell-fate decisions in adult mice. Scrib is undetectable in quiescent cells but becomes expressed during activation. Scrib is asymmetrically distributed in dividing daughter cells, with robust accumulation in cells committed to myogenic differentiation. Low Scrib expression is associated with the proliferative state and preventing self-renewal, whereas high Scrib levels reduce satellite cell proliferation. Satellite-cell-specific knockout of Scrib in mice causes a drastic and insurmountable defect in muscle regeneration. Thus, Scrib is a regulator of tissue stem cells, controlling population expansion and self-renewal with Scrib expression dynamics directing satellite cell fate.

  9. The Vertebrate Protein Dead End Maintains Primordial Germ Cell Fate by Inhibiting Somatic Differentiation.

    Science.gov (United States)

    Gross-Thebing, Theresa; Yigit, Sargon; Pfeiffer, Jana; Reichman-Fried, Michal; Bandemer, Jan; Ruckert, Christian; Rathmer, Christin; Goudarzi, Mehdi; Stehling, Martin; Tarbashevich, Katsiaryna; Seggewiss, Jochen; Raz, Erez

    2017-12-18

    Maintaining cell fate relies on robust mechanisms that prevent the differentiation of specified cells into other cell types. This is especially critical during embryogenesis, when extensive cell proliferation, patterning, and migration events take place. Here we show that vertebrate primordial germ cells (PGCs) are protected from reprogramming into other cell types by the RNA-binding protein Dead end (Dnd). PGCs knocked down for Dnd lose their characteristic morphology and adopt various somatic cell fates. Concomitantly, they gain a gene expression profile reflecting differentiation into cells of different germ layers, in a process that we could direct by expression of specific cell-fate determinants. Importantly, we visualized these events within live zebrafish embryos, which provide temporal information regarding cell reprogramming. Our results shed light on the mechanisms controlling germ cell fate maintenance and are relevant for the formation of teratoma, a tumor class composed of cells from more than one germ layer. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Tracing the fate of limbal epithelial progenitor cells in the murine cornea.

    Science.gov (United States)

    Di Girolamo, N; Bobba, S; Raviraj, V; Delic, N C; Slapetova, I; Nicovich, P R; Halliday, G M; Wakefield, D; Whan, R; Lyons, J G

    2015-01-01

    Stem cell (SC) division, deployment, and differentiation are processes that contribute to corneal epithelial renewal. Until now studying the destiny of these cells in a living mammal has not been possible. However, the advent of inducible multicolor genetic tagging and powerful imaging technologies has rendered this achievable in the translucent and readily accessible murine cornea. K14CreER(T2)-Confetti mice that harbor two copies of the Brainbow 2.1 cassette, yielding up to 10 colors from the stochastic recombination of fluorescent proteins, were used to monitor K-14(+) progenitor cell dynamics within the corneal epithelium in live animals. Multicolored columns of cells emerged from the basal limbal epithelium as they expanded and migrated linearly at a rate of 10.8 µm/day toward the central cornea. Moreover, the permanent expression of fluorophores, passed on from progenitor to progeny, assisted in discriminating individual clones as spectrally distinct streaks containing more than 1,000 cells within the illuminated area. The centripetal clonal expansion is suggestive that a single progenitor cell is responsible for maintaining a narrow corridor of corneal epithelial cells. Our data are in agreement with the limbus as the repository for SC as opposed to SC being distributed throughout the central cornea. This is the first report describing stem/progenitor cell fate determination in the murine cornea using multicolor genetic tracing. This model represents a powerful new resource to monitor SC kinetics and fate choice under homeostatic conditions, and may assist in assessing clonal evolution during corneal development, aging, wound-healing, disease, and following transplantation. © 2014 AlphaMed Press.

  11. Cell fate establishment during early development of cyprinid fishes, with special emphasis on the formation of the primordial germ cells

    NARCIS (Netherlands)

    Gevers, P.

    1992-01-01

    Cell fates can be established either by preformation or by epigenesis. With respect to primordial germ cells (PGCs) it has been shown that the Amphibia exhibit both types of cell fate establishment. Therefore, it is important to study the germ cell origin of the evolutionary lower class of

  12. Impaired removal of H3K4 methylation affects cell fate determination and gene transcription

    DEFF Research Database (Denmark)

    Lussi, Yvonne C; Mariani, Luca; Rundsten, Carsten Friis

    2016-01-01

    genetic locus, a direct RBR-2 target gene required for vulva precursor cell fate acquisition, shows that RBR-2 controls the epigenetic signature of the lin-11 vulva-specific enhancer and lin-11 expression, providing in vivo evidences that RBR-2 can positively regulate transcription and cell fate...

  13. The linear interplay of intrinsic and extrinsic noises ensures a high accuracy of cell fate selection in budding yeast

    Science.gov (United States)

    Li, Yongkai; Yi, Ming; Zou, Xiufen

    2014-01-01

    To gain insights into the mechanisms of cell fate decision in a noisy environment, the effects of intrinsic and extrinsic noises on cell fate are explored at the single cell level. Specifically, we theoretically define the impulse of Cln1/2 as an indication of cell fates. The strong dependence between the impulse of Cln1/2 and cell fates is exhibited. Based on the simulation results, we illustrate that increasing intrinsic fluctuations causes the parallel shift of the separation ratio of Whi5P but that increasing extrinsic fluctuations leads to the mixture of different cell fates. Our quantitative study also suggests that the strengths of intrinsic and extrinsic noises around an approximate linear model can ensure a high accuracy of cell fate selection. Furthermore, this study demonstrates that the selection of cell fates is an entropy-decreasing process. In addition, we reveal that cell fates are significantly correlated with the range of entropy decreases. PMID:25042292

  14. The role of catecholamines in mesenchymal stem cell fate.

    Science.gov (United States)

    Hajifathali, Abbas; Saba, Fakhredin; Atashi, Amir; Soleimani, Masoud; Mortaz, Esmaeil; Rasekhi, Mahsa

    2014-12-01

    Mesenchymal stem cells (MSCs) are multipotent stem cells found in many adult tissues, especially bone marrow (BM) and are capable of differentiation into various lineage cells such as osteoblasts, adipocytes, chondrocytes and myocytes. Moreover, MSCs can be mobilized from connective tissue into circulation and from there to damaged sites to contribute to regeneration processes. MSCs commitment and differentiation are controlled by complex activities involving signal transduction through cytokines and catecholamines. There has been an increasing interest in recent years in the neural system, functioning in the support of stem cells like MSCs. Recent efforts have indicated that the catecholamine released from neural and not neural cells could be affected characteristics of MSCs. However, there have not been review studies of most aspects involved in catecholamines-mediated functions of MSCs. Thus, in this review paper, we will try to describe the current state of catecholamines in MSCs destination and discuss strategies being used for catecholamines for migration of these cells to damaged tissues. Then, the role of the nervous system in the induction of osteogenesis, adipogenesis, chondrogenesis and myogenesis from MSCs is discussed. Recent progress in studies of signaling transduction of catecholamines in determination of the final fate of MSCs is highlighted. Hence, the knowledge of interaction between MSCs with the neural system could be applied towards the development of new diagnostic and treatment alternatives for human diseases.

  15. Senescence and apoptosis: dueling or complementary cell fates?

    Science.gov (United States)

    Childs, Bennett G; Baker, Darren J; Kirkland, James L; Campisi, Judith; van Deursen, Jan M

    2014-01-01

    In response to a variety of stresses, mammalian cells undergo a persistent proliferative arrest known as cellular senescence. Many senescence-inducing stressors are potentially oncogenic, strengthening the notion that senescence evolved alongside apoptosis to suppress tumorigenesis. In contrast to apoptosis, senescent cells are stably viable and have the potential to influence neighboring cells through secreted soluble factors, which are collectively known as the senescence-associated secretory phenotype (SASP). However, the SASP has been associated with structural and functional tissue and organ deterioration and may even have tumor-promoting effects, raising the interesting evolutionary question of why apoptosis failed to outcompete senescence as a superior cell fate option. Here, we discuss the advantages that the senescence program may have over apoptosis as a tumor protective mechanism, as well as non-neoplastic functions that may have contributed to its evolution. We also review emerging evidence for the idea that senescent cells are present transiently early in life and are largely beneficial for development, regeneration and homeostasis, and only in advanced age do senescent cells accumulate to an organism’s detriment. PMID:25312810

  16. Delta1 expression, cell cycle exit, and commitment to a specific secretory fate coincide within a few hours in the mouse intestinal stem cell system.

    Directory of Open Access Journals (Sweden)

    Despina Stamataki

    Full Text Available The stem cells of the small intestine are multipotent: they give rise, via transit-amplifying cell divisions, to large numbers of columnar absorptive cells mixed with much smaller numbers of three different classes of secretory cells--mucus-secreting goblet cells, hormone-secreting enteroendocrine cells, and bactericide-secreting Paneth cells. Notch signaling is known to control commitment to a secretory fate, but why are the secretory cells such a small fraction of the population, and how does the diversity of secretory cell types arise? Using the mouse as our model organism, we find that secretory cells, and only secretory cells, pass through a phase of strong expression of the Notch ligand Delta1 (Dll1. Onset of this Dll1 expression coincides with a block to further cell division and is followed in much less than a cell cycle time by expression of Neurog3--a marker of enteroendocrine fate--or Gfi1--a marker of goblet or Paneth cell fate. By conditional knock-out of Dll1, we confirm that Delta-Notch signaling controls secretory commitment through lateral inhibition. We infer that cells stop dividing as they become committed to a secretory fate, while their neighbors continue dividing, explaining the final excess of absorptive over secretory cells. Our data rule out schemes in which cells first become committed to be secretory, and then diversify through subsequent cell divisions. A simple mathematical model shows how, instead, Notch signaling may simultaneously govern the commitment to be secretory and the choice between alternative modes of secretory differentiation.

  17. Generation of bivalent chromatin domains during cell fate decisions

    Directory of Open Access Journals (Sweden)

    De Gobbi Marco

    2011-06-01

    Full Text Available Abstract Background In self-renewing, pluripotent cells, bivalent chromatin modification is thought to silence (H3K27me3 lineage control genes while 'poising' (H3K4me3 them for subsequent activation during differentiation, implying an important role for epigenetic modification in directing cell fate decisions. However, rather than representing an equivalently balanced epigenetic mark, the patterns and levels of histone modifications at bivalent genes can vary widely and the criteria for identifying this chromatin signature are poorly defined. Results Here, we initially show how chromatin status alters during lineage commitment and differentiation at a single well characterised bivalent locus. In addition we have determined how chromatin modifications at this locus change with gene expression in both ensemble and single cell analyses. We also show, on a global scale, how mRNA expression may be reflected in the ratio of H3K4me3/H3K27me3. Conclusions While truly 'poised' bivalently modified genes may exist, the original hypothesis that all bivalent genes are epigenetically premarked for subsequent expression might be oversimplistic. In fact, from the data presented in the present work, it is equally possible that many genes that appear to be bivalent in pluripotent and multipotent cells may simply be stochastically expressed at low levels in the process of multilineage priming. Although both situations could be considered to be forms of 'poising', the underlying mechanisms and the associated implications are clearly different.

  18. Stimulating Fracture Healing in Ischemic Environments: Does Oxygen Direct Stem Cell Fate during Fracture Healing?

    Science.gov (United States)

    Miclau, Katherine R.; Brazina, Sloane A.; Bahney, Chelsea S.; Hankenson, Kurt D.; Hunt, Thomas K.; Marcucio, Ralph S.; Miclau, Theodore

    2017-01-01

    Bone fractures represent an enormous societal and economic burden as one of the most prevalent causes of disability worldwide. Each year, nearly 15 million people are affected by fractures in the United States alone. Data indicate that the blood supply is critical for fracture healing; as data indicate that concomitant bone and vascular injury are major risk factors for non-union. However, the various role(s) that the vasculature plays remains speculative. Fracture stabilization dictates stem cell fate choices during repair. In stabilized fractures stem cells differentiate directly into osteoblasts and heal the injury by intramembranous ossification. In contrast, in non-stable fractures stem cells differentiate into chondrocytes and the bone heals through endochondral ossification, where a cartilage template transforms into bone as the chondrocytes transform into osteoblasts. One suggested role of the vasculature has been to participate in the stem cell fate decisions due to delivery of oxygen. In stable fractures, the blood vessels are thought to remain intact and promote osteogenesis, while in non-stable fractures, continual disruption of the vasculature creates hypoxia that favors formation of cartilage, which is avascular. However, recent data suggests that non-stable fractures are more vascularized than stable fractures, that oxygen does not appear associated with differentiation of stem cells into chondrocytes and osteoblasts, that cartilage is not hypoxic, and that oxygen, not sustained hypoxia, is required for angiogenesis. These unexpected results, which contrast other published studies, are indicative of the need to better understand the complex, spatio-temporal regulation of vascularization and oxygenation in fracture healing. This work has also revealed that oxygen, along with the promotion of angiogenesis, may be novel adjuvants that can stimulate healing in select patient populations. PMID:28523266

  19. Human mammary progenitor cell fate decisions are productsof interactions with combinatorial microenvironments

    DEFF Research Database (Denmark)

    LaBarge, Mark A.; Nelson, Celeste M.; Villadsen, René

    2009-01-01

    combinations of cell-extrinsic mammary gland proteins and ECM molecules that imposed specific cell fates on bipotent human mammary progenitor cells.Micropatterned cell culture surfaces were fabricated to distinguish between the instructive effects of cell-cell versus cell-ECM interactions, as well......, maintain the progenitor state, and guide progenitor differentiation towards myoepithelial and luminal lineages....

  20. Cellular Programming and Reprogramming: Sculpting Cell Fate for the Production of Dopamine Neurons for Cell Therapy

    Directory of Open Access Journals (Sweden)

    Julio C. Aguila

    2012-01-01

    success of clinical applications depends on our ability to steer pluripotent stem cells towards the right neuronal identity. In Parkinson disease, the loss of dopamine neurons is more pronounced in the ventrolateral population that projects to the sensorimotor striatum. Because synapses are highly specific, only neurons with this precise identity will contribute, upon transplantation, to the synaptic reconstruction of the dorsal striatum. Thus, understanding the developmental cell program of the mesostriatal dopamine neurons is critical for the identification of the extrinsic signals and cell-intrinsic factors that instruct and, ultimately, determine cell identity. Here, we review how extrinsic signals and transcription factors act together during development to shape midbrain cell fates. Further, we discuss how these same factors can be applied in vitro to induce, select, and reprogram cells to the mesostriatal dopamine fate.

  1. Msx2 in ameloblast cell fate and activity

    Directory of Open Access Journals (Sweden)

    Sylvie eBabajko

    2015-01-01

    Full Text Available While many effectors have been identified in enamel matrix and cells via genetic studies, physiological networks underlying their expression levels and thus the natural spectrum of enamel thickness and degree of mineralization are now just emerging. Several transcription factors are candidates for enamel gene expression regulation and thus the control of enamel quality. Some of these factors, such as MSX2, are mainly confined to the dental epithelium. MSX2 homeoprotein controls several stages of the ameloblast life cycle. This chapter introduces MSX2 and its target genes in the ameloblast and provides an overview of knowledge regarding its effects in vivo in transgenic mouse models. Currently available in vitro data on the role of MSX2 as a transcription factor and its links to other players in ameloblast gene regulation are considered. MSX2 modulations are relevant to the interplay between developmental, hormonal and environmental pathways and in vivo investigations, notably in the rodent incisor, have provided insight into dental physiology. Indeed, in vivo models are particularly promising for investigating enamel formation and MSX2 function in ameloblast cell fate.MSX2 may be central to the temporal-spatial restriction of enamel protein production by the dental epithelium and thus regulation of enamel quality (thickness and mineralization level under physiological and pathological conditions. Studies on MSX2 show that amelogenesis is not an isolated process but is part of the more general physiology of coordinated dental-bone complex growth.

  2. The WTX Tumor Suppressor Regulates Mesenchymal Progenitor Cell Fate Specification

    Science.gov (United States)

    Lotinun, Sutada; Akhavanfard, Sara; Coffman, Erik J.; Cook, Edward B.; Stoykova, Svetlana; Mukherjee, Siddhartha; Schoonmaker, Jesse A.; Burger, Alexa; Kim, Woo Jae; Kronenberg, Henry M.; Baron, Roland; Haber, Daniel A.; Bardeesy, Nabeel

    2014-01-01

    SUMMARY WTX is an X-linked tumor suppressor targeted by somatic mutations in Wilms tumor, a pediatric kidney cancer, and by germline inactivation in osteopathia striata with cranial sclerosis, a bone overgrowth syndrome. Here, we show that Wtx deletion in mice causes neonatal lethality, somatic overgrowth, and malformation of multiple mesenchyme-derived tissues, including bone, fat, kidney, heart, and spleen. Inactivation of Wtx at different developmental stages and in primary mesenchymal progenitor cells (MPCs) reveals that bone mass increase and adipose tissue deficiency are due to altered lineage fate decisions coupled with delayed terminal differentiation. Specification defects in MPCs result from aberrant β-catenin activation, whereas alternative pathways contribute to the subsequently delayed differentiation of lineage-restricted cells. Thus, Wtx is a regulator of MPC commitment and differentiation with stage-specific functions in inhibiting canonical Wnt signaling. Furthermore, the constellation of anomalies in Wtx null mice suggests that this tumor suppressor broadly regulates MPCs in multiple tissues. PMID:21571217

  3. Multipotent versus differentiated cell fate selection in the developing Drosophila airways

    Science.gov (United States)

    Matsuda, Ryo; Hosono, Chie; Samakovlis, Christos; Saigo, Kaoru

    2015-01-01

    Developmental potentials of cells are tightly controlled at multiple levels. The embryonic Drosophila airway tree is roughly subdivided into two types of cells with distinct developmental potentials: a proximally located group of multipotent adult precursor cells (P-fate) and a distally located population of more differentiated cells (D-fate). We show that the GATA-family transcription factor (TF) Grain promotes the P-fate and the POU-homeobox TF Ventral veinless (Vvl/Drifter/U-turned) stimulates the D-fate. Hedgehog and receptor tyrosine kinase (RTK) signaling cooperate with Vvl to drive the D-fate at the expense of the P-fate while negative regulators of either of these signaling pathways ensure P-fate specification. Local concentrations of Decapentaplegic/BMP, Wingless/Wnt, and Hedgehog signals differentially regulate the expression of D-factors and P-factors to transform an equipotent primordial field into a concentric pattern of radially different morphogenetic potentials, which gradually gives rise to the distal-proximal organization of distinct cell types in the mature airway. DOI: http://dx.doi.org/10.7554/eLife.09646.001 PMID:26633813

  4. Sox17-Mediated XEN Cell Conversion Identifies Dynamic Networks Controlling Cell-Fate Decisions in Embryo-Derived Stem Cells

    Directory of Open Access Journals (Sweden)

    Angela C.H. McDonald

    2014-10-01

    Full Text Available Little is known about the gene regulatory networks (GRNs distinguishing extraembryonic endoderm (ExEn stem (XEN cells from those that maintain the extensively characterized embryonic stem cell (ESC. An intriguing network candidate is Sox17, an essential transcription factor for XEN derivation and self-renewal. Here, we show that forced Sox17 expression drives ESCs toward ExEn, generating XEN cells that contribute to ExEn when placed back into early mouse embryos. Transient Sox17 expression is sufficient to drive this fate change during which time cells transit through distinct intermediate states prior to the generation of functional XEN-like cells. To orchestrate this conversion process, Sox17 acts in autoregulatory and feedforward network motifs, regulating dynamic GRNs directing cell fate. Sox17-mediated XEN conversion helps to explain the regulation of cell-fate changes and reveals GRNs regulating lineage decisions in the mouse embryo.

  5. Engineering the human pluripotent stem cell microenvironment to direct cell fate.

    Science.gov (United States)

    Hazeltine, Laurie B; Selekman, Joshua A; Palecek, Sean P

    2013-11-15

    Human pluripotent stem cells (hPSCs), including both embryonic stem cells and induced pluripotent stem cells, offer a potential cell source for research, drug screening, and regenerative medicine applications due to their unique ability to self-renew or differentiate to any somatic cell type. Before the full potential of hPSCs can be realized, robust protocols must be developed to direct their fate. Cell fate decisions are based on components of the surrounding microenvironment, including soluble factors, substrate or extracellular matrix, cell-cell interactions, mechanical forces, and 2D or 3D architecture. Depending on their spatio-temporal context, these components can signal hPSCs to either self-renew or differentiate to cell types of the ectoderm, mesoderm, or endoderm. Researchers working at the interface of engineering and biology have identified various factors which can affect hPSC fate, often based on lessons from embryonic development, and they have utilized this information to design in vitro niches which can reproducibly direct hPSC fate. This review highlights culture systems that have been engineered to promote self-renewal or differentiation of hPSCs, with a focus on studies that have elucidated the contributions of specific microenvironmental cues in the context of those culture systems. We propose the use of microsystem technologies for high-throughput screening of spatial-temporal presentation of cues, as this has been demonstrated to be a powerful approach for differentiating hPSCs to desired cell types. Copyright © 2013 Elsevier Inc. All rights reserved.

  6. Asymmetric PI3K Signaling Driving Developmental and Regenerative Cell Fate Bifurcation

    Directory of Open Access Journals (Sweden)

    Wen-Hsuan W. Lin

    2015-12-01

    Full Text Available Metazoan sibling cells often diverge in activity and identity, suggesting links between growth signals and cell fate. We show that unequal transduction of nutrient-sensitive PI3K/AKT/mTOR signaling during cell division bifurcates transcriptional networks and fates of kindred cells. A sibling B lymphocyte with stronger signaling, indexed by FoxO1 inactivation and IRF4 induction, undergoes PI3K-driven Pax5 repression and plasma cell determination, while its sibling with weaker PI3K activity renews a memory or germinal center B cell fate. PI3K-driven effector T cell determination silences TCF1 in one sibling cell, while its PI3K-attenuated sibling self-renews in tandem. Prior to bifurcations achieving irreversible plasma or effector cell fate determination, asymmetric signaling during initial divisions specifies a more proliferative, differentiation-prone lymphocyte in tandem with a more quiescent memory cell sibling. By triggering cell division but transmitting unequal intensity between sibling cells, nutrient-sensitive signaling may be a frequent arbiter of cell fate bifurcations during development and repair.

  7. Deubiquitylating enzyme UBP64 controls cell fate through stabilization of the transcriptional repressor tramtrack

    NARCIS (Netherlands)

    P.K. Bajpe (Prashanth Kumar); J.A. van der Knaap (Jan); J.A.A. Demmers (Jeroen); K. Bezstarosti (Karel); A. Bassett (Andrew); H.M.M. van Beusekom (Heleen); A.A. Travers (Andrew); C.P. Verrijzer (Peter)

    2008-01-01

    textabstractProtein ubiquitylation plays a central role in multiple signal transduction pathways. However, the substrate specificity and potential developmental roles of deubiquitylating enzymes remain poorly understood. Here, we show that the Drosophila ubiquitin protease UBP64 controls cell fate

  8. Dynamic transcriptional signature and cell fate analysis reveals plasticity of individual neural plate border cells

    Science.gov (United States)

    Roellig, Daniela; Tan-Cabugao, Johanna; Esaian, Sevan; Bronner, Marianne E

    2017-01-01

    The ‘neural plate border’ of vertebrate embryos contains precursors of neural crest and placode cells, both defining vertebrate characteristics. How these lineages segregate from neural and epidermal fates has been a matter of debate. We address this by performing a fine-scale quantitative temporal analysis of transcription factor expression in the neural plate border of chick embryos. The results reveal significant overlap of transcription factors characteristic of multiple lineages in individual border cells from gastrula through neurula stages. Cell fate analysis using a Sox2 (neural) enhancer reveals that cells that are initially Sox2+ cells can contribute not only to neural tube but also to neural crest and epidermis. Moreover, modulating levels of Sox2 or Pax7 alters the apportionment of neural tube versus neural crest fates. Our results resolve a long-standing question and suggest that many individual border cells maintain ability to contribute to multiple ectodermal lineages until or beyond neural tube closure. DOI: http://dx.doi.org/10.7554/eLife.21620.001 PMID:28355135

  9. NOTCH SIGNALING ALTERS SENSORY OR NEURONAL CELL FATE SPECIFICATION OF INNER EAR STEM CELLS

    Science.gov (United States)

    Jeon, Sang-Jun; Fujioka, Masato; Kim, Shi-Chan; Edge, Albert S.B.

    2011-01-01

    Multipotent progenitor cells in the otic placode give rise to the specialized cell types of the inner ear, including neurons, supporting cells and hair cells. The mechanisms governing acquisition of specific fates by the cells that form the cochleovestibular organs remain poorly characterized. Here we show that whereas blocking Notch signaling with a γ-secretase inhibitor increased the conversion of inner ear stem cells to hair cells by a mechanism that involved the upregulation of bHLH transcription factor, Math1 (mouse Atoh1), differentiation to a neuronal lineage was increased by expression of the Notch intracellular domain. The shift to a neuronal lineage could be attributed in part to the continued cell proliferation in cells that did not undergo sensory cell differentiation due to the high Notch signaling, but also involved upregulation of Ngn1. The Notch intracellular domain influenced Ngn1 indirectly by upregulation of Sox2, a transcription factor expressed in many neural progenitor cells, and directly by an interaction with an RBP-J binding site in the Ngn1 promoter/enhancer. The induction of Ngn1 was blocked partially by mutation of the RBP-J site and nearly completely when the mutation was combined with inhibition of Sox2 expression. Thus Notch signaling had a significant role in the fate specification of neurons and hair cells from inner ear stem cells, and decisions about cell fate were mediated in part by a differential effect of combinatorial signaling by Notch and Sox2 on the expression of bHLH transcription factors. PMID:21653840

  10. Metabolism and the Control of Cell Fate Decisions and Stem Cell Renewal

    Science.gov (United States)

    Ito, Kyoko; Ito, Keisuke

    2016-01-01

    Although the stem cells of various tissues remain in the quiescent state to maintain their undifferentiated state, they also undergo cell divisions as required, and if necessary, even a single stem cell is able to provide for lifelong tissue homeostasis. Stem cell populations are precisely controlled by the balance between their symmetric and asymmetric divisions, with their division patterns determined by whether the daughter cells involved retain their self-renewal capacities. Recent studies have reported that metabolic pathways and the distribution of mitochondria are regulators of the division balance of stem cells and that metabolic defects can shift division balance toward symmetric commitment, which leads to stem cell exhaustion. It has also been observed that in asymmetric division, old mitochondria, which are central metabolic organelles, are segregated to the daughter cell fated to cell differentiation, whereas in symmetric division, young and old mitochondria are equally distributed between both daughter cells. Thus, metabolism and mitochondrial biology play important roles in stem cell fate decisions. As these decisions directly affect tissue homeostasis, understanding their regulatory mechanisms in the context of cellular metabolism is critical. PMID:27482603

  11. Prostaglandin E2 Regulates Liver versus Pancreas Cell Fate Decisions and Endodermal Outgrowth

    Science.gov (United States)

    Nissim, Sahar; Sherwood, Richard I.; Wucherpfennig, Julia; Saunders, Diane; Harris, James M.; Esain, Virginie; Carroll, Kelli J.; Frechette, Gregory M.; Kim, Andrew J.; Hwang, Katie L.; Cutting, Claire C.; Elledge, Susanna; North, Trista E.; Goessling, Wolfram

    2014-01-01

    SUMMARY The liver and pancreas arise from common endodermal progenitors. How these distinct cell fates are specified is poorly understood. Here, we describe prostaglandin E2 (PGE2) as a regulator of endodermal fate specification during development. Modulating PGE2 activity has opposing effects on liver-versus-pancreas specification in zebrafish embryos as well as mouse endodermal progenitors. The PGE2 synthetic enzyme cox2a and receptor ep2a are patterned such that cells closest to PGE2 synthesis acquire a liver fate whereas more distant cells acquire a pancreas fate. PGE2 interacts with the bmp2b pathway to regulate fate specification. At later stages of development, PGE2 acting via the ep4a receptor promotes outgrowth of both the liver and pancreas. PGE2 remains important for adult organ growth, as it modulates liver regeneration. This work provides in vivo evidence that PGE2 may act as a morphogen to regulate cell fate decisions and outgrowth of the embryonic endodermal anlagen. PMID:24530296

  12. Synergic Functions of miRNAs Determine Neuronal Fate of Adult Neural Stem Cells

    Directory of Open Access Journals (Sweden)

    Meritxell Pons-Espinal

    2017-04-01

    Full Text Available Adult neurogenesis requires the precise control of neuronal versus astrocyte lineage determination in neural stem cells. While microRNAs (miRNAs are critically involved in this step during development, their actions in adult hippocampal neural stem cells (aNSCs has been unclear. As entry point to address that question we chose DICER, an endoribonuclease essential for miRNA biogenesis and other RNAi-related processes. By specific ablation of Dicer in aNSCs in vivo and in vitro, we demonstrate that miRNAs are required for the generation of new neurons, but not astrocytes, in the adult murine hippocampus. Moreover, we identify 11 miRNAs, of which 9 have not been previously characterized in neurogenesis, that determine neurogenic lineage fate choice of aNSCs at the expense of astrogliogenesis. Finally, we propose that the 11 miRNAs sustain adult hippocampal neurogenesis through synergistic modulation of 26 putative targets from different pathways.

  13. Noninvasive Assessment of Cell Fate and Biology in Transplanted Mesenchymal Stem Cells.

    Science.gov (United States)

    Franchi, Federico; Rodriguez-Porcel, Martin

    2017-01-01

    Recently, molecular imaging has become a conditio sine qua non for cell-based regenerative medicine. Developments in molecular imaging techniques, such as reporter gene technology, have increasingly enabled the noninvasive assessment of the fate and biology of cells after cardiovascular applications. In this context, bioluminescence imaging is the most commonly used imaging modality in small animal models of preclinical studies. Here, we present a detailed protocol of a reporter gene imaging approach for monitoring the viability and biology of Mesenchymal Stem Cells transplanted in a mouse model of myocardial ischemia reperfusion injury.

  14. Factor graph analysis of live cell-imaging data reveals mechanisms of cell fate decisions.

    Science.gov (United States)

    Niederberger, Theresa; Failmezger, Henrik; Uskat, Diana; Poron, Don; Glauche, Ingmar; Scherf, Nico; Roeder, Ingo; Schroeder, Timm; Tresch, Achim

    2015-06-01

    Cell fate decisions have a strong stochastic component. The identification of the underlying mechanisms therefore requires a rigorous statistical analysis of large ensembles of single cells that were tracked and phenotyped over time. We introduce a probabilistic framework for testing elementary hypotheses on dynamic cell behavior using time-lapse cell-imaging data. Factor graphs, probabilistic graphical models, are used to properly account for cell lineage and cell phenotype information. Our model is applied to time-lapse movies of murine granulocyte-macrophage progenitor (GMP) cells. It decides between competing hypotheses on the mechanisms of their differentiation. Our results theoretically substantiate previous experimental observations that lineage instruction, not selection is the cause for the differentiation of GMP cells into mature monocytes or neutrophil granulocytes. The Matlab source code is available at http://treschgroup.de/Genealogies.html. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. SMAD4-mediated WNT signaling controls the fate of cranial neural crest cells during tooth morphogenesis

    Science.gov (United States)

    Li, Jingyuan; Huang, Xiaofeng; Xu, Xun; Mayo, Julie; Bringas, Pablo; Jiang, Rulang; Wang, Songling; Chai, Yang

    2011-01-01

    TGFβ/BMP signaling regulates the fate of multipotential cranial neural crest (CNC) cells during tooth and jawbone formation as these cells differentiate into odontoblasts and osteoblasts, respectively. The functional significance of SMAD4, the common mediator of TGFβ/BMP signaling, in regulating the fate of CNC cells remains unclear. In this study, we investigated the mechanism of SMAD4 in regulating the fate of CNC-derived dental mesenchymal cells through tissue-specific inactivation of Smad4. Ablation of Smad4 results in defects in odontoblast differentiation and dentin formation. Moreover, ectopic bone-like structures replaced normal dentin in the teeth of Osr2-IresCre;Smad4fl/fl mice. Despite the lack of dentin, enamel formation appeared unaffected in Osr2-IresCre;Smad4fl/fl mice, challenging the paradigm that the initiation of enamel development depends on normal dentin formation. At the molecular level, loss of Smad4 results in downregulation of the WNT pathway inhibitors Dkk1 and Sfrp1 and in the upregulation of canonical WNT signaling, including increased β-catenin activity. More importantly, inhibition of the upregulated canonical WNT pathway in Osr2-IresCre;Smad4fl/fl dental mesenchyme in vitro partially rescued the CNC cell fate change. Taken together, our study demonstrates that SMAD4 plays a crucial role in regulating the interplay between TGFβ/BMP and WNT signaling to ensure the proper CNC cell fate decision during organogenesis. PMID:21490069

  16. Silencing of hepatic fate-conversion factors induce tumorigenesis in reprogrammed hepatic progenitor-like cells.

    Science.gov (United States)

    Serrano, Felipe; García-Bravo, Maria; Blazquez, Marina; Torres, Josema; Castell, Jose V; Segovia, Jose C; Bort, Roque

    2016-07-27

    Several studies have reported the direct conversion of mouse fibroblasts to hepatocyte-like cells with different degrees of maturation by expression of hepatic fate-conversion factors. We have used a combination of lentiviral vectors expressing hepatic fate-conversion factors with Oct4, Sox2, Klf4, and Myc to convert mouse embryonic fibroblasts into hepatic cells. We have generated hepatic cells with progenitor-like features (iHepL cells). iHepL cells displayed basic hepatocyte functions but failed to perform functions characteristic of mature hepatocytes such as significant Cyp450 or urea cycle activities. iHepL cells expressed multiple hepatic-specific transcription factors and functional genes characteristic of immature hepatocytes and cholangiocytes, as well as high levels of Foxl1, Cd24a, and Lgr5, specific markers of hepatic progenitor cells. When transplanted into partial hepatectomized and hepatic irradiated mice, they differentiated into hepatocytes and cholangiocytes. However, iHepL cells formed malignant non-teratoma cell aggregations in one out of five engrafted livers and five out of five xenografts assays. All the cells in these tumors had silenced key hepatic fate-conversion factors, and lost hepatic features. This study highlights the dangers of using pluripotency factors in reprogramming strategies when fate-conversion factors are silenced in vivo, and urges us to perform extensive tumorigenic tests in reprogrammed cells.

  17. ¬Mesenchymal Stem Cell Fate: Applying Biomaterials for Control of Stem Cell Behaviour

    Directory of Open Access Journals (Sweden)

    Hilary Jane Anderson

    2016-05-01

    Full Text Available Mesenchymal Stem Cell Fate: Applying Biomaterials for Control of Stem Cell BehaviourHilary J Anderson1, Jugal Kishore Sahoo2, Rein V Ulijn2,3, Matthew J Dalby1*1 Centre for Cell Engineering, University of Glasgow, Glasgow, UK.2 Technology and Innovation centre, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, UK. 3 Advanced Science Research Centre (ASRC and Hunter College, City University of New York, NY 10031, NY, USA. Correspondence:*Hilary Andersonh.anderson.1@research.gla.ac.ukKeywords: mesenchymal stem cells, bioengineering, materials synthesis, nanotopography, stimuli responsive material□AbstractThe materials pipeline for biomaterials and tissue engineering applications is under continuous development. Specifically, there is great interest in the use of designed materials in the stem cell arena as materials can be used to manipulate the cells providing control of behaviour. This is important as the ability to ‘engineer’ complexity and subsequent in vitro growth of tissues and organs is a key objective for tissue engineers. This review will describe the nature of the materials strategies, both static and dynamic, and their influence specifically on mesenchymal stem cell fate.

  18. Progressive determination of cell fates along the dorsoventral axis in the sea urchin Heliocidaris erythrogramma.

    Science.gov (United States)

    Henry, J J; Raff, R A

    1994-10-01

    In the direct-developing sea urchin Heliocidaris erythrogramma the first cleavage division bisects the dorsoventral axis of the developing embryo along a frontal plane. In the two-celled embryo one of the blastomeres, the ventral cell (V), gives rise to all pigmented mesenchyme, as well as to the vestibule of the echinus rudiment. Upon isolation, however, the dorsal blastomere (D) displays some regulation, and is able to form a small number of pigmented mesenchyme cells and even a vestibule. We have examined the spatial and temporal determination of cell fates along the dorsoventral axis during subsequent development. We demonstrate that the dorsoventral axis is resident within both cells of the two-celled embryo, but only the ventral pole of this axis has a rigidly fixed identity this early in development. The polarity of this axis remains the same in half-embryos developing from isolated ventral (V) blastomeres, but it can flip 180° in half-embryos developing from isolated dorsal (D) blastomeres. We find that cell fates are progressively determined along the dorsoventral axis up to the time of gastrulation. The ability of dorsal half-embryos to differentiate ventral cell fates diminishes as they are isolated at progressively later stages of development. These results suggest that the determination of cell fates along the dorsoventral axis in H. erythrogramma is regulated via inductive interactions organized by cells within the ventral half of the embryo.

  19. Mammalian aPKC/Par polarity complex mediated regulation of epithelial division orientation and cell fate

    Energy Technology Data Exchange (ETDEWEB)

    Vorhagen, Susanne; Niessen, Carien M., E-mail: carien.niessen@uni-koeln.de

    2014-11-01

    Oriented cell division is a key regulator of tissue architecture and crucial for morphogenesis and homeostasis. Balanced regulation of proliferation and differentiation is an essential property of tissues not only to drive morphogenesis but also to maintain and restore homeostasis. In many tissues orientation of cell division is coupled to the regulation of differentiation producing daughters with similar (symmetric cell division, SCD) or differential fate (asymmetric cell division, ACD). This allows the organism to generate cell lineage diversity from a small pool of stem and progenitor cells. Division orientation and/or the ratio of ACD/SCD need to be tightly controlled. Loss of orientation or an altered ratio can promote overgrowth, alter tissue architecture and induce aberrant differentiation, and have been linked to morphogenetic diseases, cancer and aging. A key requirement for oriented division is the presence of a polarity axis, which can be established through cell intrinsic and/or extrinsic signals. Polarity proteins translate such internal and external cues to drive polarization. In this review we will focus on the role of the polarity complex aPKC/Par3/Par6 in the regulation of division orientation and cell fate in different mammalian epithelia. We will compare the conserved function of this complex in mitotic spindle orientation and distribution of cell fate determinants and highlight common and differential mechanisms in which this complex is used by tissues to adapt division orientation and cell fate to the specific properties of the epithelium.

  20. Deep sequencing as a probe of normal stem cell fate and preneoplasia in human epidermis.

    Science.gov (United States)

    Simons, Benjamin D

    2016-01-05

    Using deep sequencing technology, methods based on the sporadic acquisition of somatic DNA mutations in human tissues have been used to trace the clonal evolution of progenitor cells in diseased states. However, the potential of these approaches to explore cell fate behavior of normal tissues and the initiation of preneoplasia remain underexploited. Focusing on the results of a recent deep sequencing study of eyelid epidermis, we show that the quantitative analysis of mutant clone size provides a general method to resolve the pattern of normal stem cell fate and to detect and characterize the mutational signature of rare field transformations in human tissues, with implications for the early detection of preneoplasia.

  1. Ethanol alters cell fate of fetal human brain-derived stem and progenitor cells.

    Science.gov (United States)

    Vangipuram, Sharada D; Lyman, William D

    2010-09-01

    Prenatal ethanol (ETOH) exposure can lead to fetal alcohol spectrum disorder (FASD). We previously showed that ETOH alters cell adhesion molecule gene expression and increases neurosphere size in fetal brain-derived neural stem cells (NSC). Here, our aim was to determine the effect of ETOH on the cell fate of NSC, premature glial-committed precursor cells (GCP), and premature neuron-committed progenitor cells (NCP). NSC, GCP, and NCP were isolated from normal second-trimester fetal human brains (n = 3) by positive selection using magnetic microbeads labeled with antibodies to CD133 (NSC), A2B5 (GCP), or PSA-NCAM (NCP). As a result of the small percentage in each brain, NSC were cultured in mitogenic media for 72 hours to produce neurospheres. The neurospheres from NSC and primary isolates of GCP and NCP were used for all experiments. Equal numbers of the 3 cell types were treated either with mitogenic media or with differentiating media, each containing 0 or 100 mM ETOH, for 120 hours. Expression of Map2a, GFAP, and O4 was determined by immunoflourescence microscopy and western blot analysis. Fluorescence intensities were quantified using Metamorph software by Molecular Devices, and the bands of western blots were quantified using densitometry. ETOH in mitogenic media promoted formation of neurospheres by NSC, GCP, and NCP. Under control conditions, GCP attached and differentiated, NSC and NCP formed neurospheres that were significantly smaller in size than those in ETOH. Under differentiating conditions, Map2a expression increased significantly in NSC and GCP and reduced significantly in NCP, and GFAP expression reduced significantly in GCP and NCP, and Gal-C expression reduced significantly in all 3 cell types in the presence of ETOH compared to controls. This study shows that ETOH alters the cell fate of neuronal stem and progenitor cells. These alterations could contribute to the mechanism for the abnormal brain development in FASD.

  2. CHOICE AND JUSTIFICATION FOR FUEL CELL ECO-MOBIL

    Directory of Open Access Journals (Sweden)

    Abramchuk, F.

    2013-06-01

    Full Text Available The problems of choice of fuel cell of choice to drive the car competitor of Shell-EcoMarathon are considered. The analysis of the concepts of fuel cells, chosen as the most rational scheme and main parameters of the components of the power plant is done. The results of calculation of the characteris-tics of the sports car with a fuel cell are given.

  3. "Choice" and destiny: the substrate composition and mechanical stability of settlement structures can mediate coral recruit fate in post-bleached reefs

    Science.gov (United States)

    Yadav, Shreya; Rathod, Pooja; Alcoverro, Teresa; Arthur, Rohan

    2016-03-01

    Increasingly frequent and intense ocean warming events seriously test the buffer and recovery capacities of tropical coral reefs. Post-disturbance, available settlement structures on a reef (often dead coral skeletons) vary considerably in their mechanical stability and substrate composition, critically influencing coral recruit settlement choice and fate. In the wake of a coral mass mortality in the Lakshadweep archipelago, we examine (1) the relative availability of recruit settlement structures (from stable to unstable: reef platform, dead massive coral, consolidated rubble, dead corymbose coral, dead tabular coral, and unconsolidated rubble) in 12 recovering reefs across three atolls in the archipelago, (2) the substrate composition [crustose coralline algae (CCA), mixed turf, macroalgae] of these structural forms, and (3) whether the choice and fate of young coral are mediated by the substrate and stability of different structural forms. For this, we measured the abundance and distribution of recruit (corals of 24 common coral genera. Four years after the mass mortality, reefs differed considerably in composition of settlement structures. The structures themselves varied significantly in substrate cover with dead tables largely covered in CCA [60 ± 6.05 % (SE)] and dead corymbose coral dominated by mixed turf (61.83 ± 3.8 %). The youngest visible recruits (coral choice, the mechanical stability of settlement structures is critical in determining post-settlement coral survival. The composition and availability of settlement structures on a reef may serve as a characteristic signature of its recovery potential, aiding in assessments of reef resilience.

  4. The fog-3 gene and regulation of cell fate in the germ line of Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, R.; Kimble, J. [Univ. of Wisconsin, Madison, WI (United States)

    1995-02-01

    In the nematode Caenorhabditis elegans, germ cells normally adopt one of three fates: mitosis, spermatogenesis or oogenesis. We have identified and characterized the gene fog-3, which is required for germ cells to differentiate as sperm rather than as oocytes. Analysis of double mutants suggests that fog-3 is absolutely required for spermatogenesis and acts at the end of the regulatory hierarchy controlling sex determination for the germ line. By contrast, mutations in fog-3 do not alter the sexual identity of other tissues. We also have characterized the null phenotype of fog-1, another gene required for spermatogenesis; we demonstrate that it too controls the sexual identity of germ cells but not of other tissues. Finally, we have studied the same interaction of these two fog genes with gld-1, a gene required for germ cells to undergo oogenesis rather than mitosis. On the basis of these results, we propose that germ-cell fate might be controlled by a set of inhibitory interactions among genes that specify one of three fates: mitosis, spermatogenesis or oogenesis. Such a regulatory network would link the adoption of one germ-cell fate to the suppression of the other two. 68 refs., 7 figs., 6 tabs.

  5. Logic programming to predict cell fate patterns and retrodict genotypes in organogenesis

    Science.gov (United States)

    Hall, Benjamin A.; Jackson, Ethan; Hajnal, Alex; Fisher, Jasmin

    2014-01-01

    Caenorhabditis elegans vulval development is a paradigm system for understanding cell differentiation in the process of organogenesis. Through temporal and spatial controls, the fate pattern of six cells is determined by the competition of the LET-23 and the Notch signalling pathways. Modelling cell fate determination in vulval development using state-based models, coupled with formal analysis techniques, has been established as a powerful approach in predicting the outcome of combinations of mutations. However, computing the outcomes of complex and highly concurrent models can become prohibitive. Here, we show how logic programs derived from state machines describing the differentiation of C. elegans vulval precursor cells can increase the speed of prediction by four orders of magnitude relative to previous approaches. Moreover, this increase in speed allows us to infer, or ‘retrodict’, compatible genomes from cell fate patterns. We exploit this technique to predict highly variable cell fate patterns resulting from dig-1 reduced-function mutations and let-23 mosaics. In addition to the new insights offered, we propose our technique as a platform for aiding the design and analysis of experimental data. PMID:24966232

  6. Germline Stem Cell Differentiation Entails Regional Control of Cell Fate Regulator GLD-1 in Caenorhabditis elegans.

    Science.gov (United States)

    Brenner, John L; Schedl, Tim

    2016-03-01

    Germline stem cell differentiation in Caenorhabditis elegans is controlled by glp-1 Notch signaling. Cell fate regulator GLD-1 is sufficient to induce meiotic entry and expressed at a high level during meiotic prophase, inhibiting mitotic gene activity. glp-1 signaling and other regulators control GLD-1 levels post-transcriptionally (low in stem cells, high in meiotic prophase), but many aspects of GLD-1 regulation are uncharacterized, including the link between glp-1-mediated transcriptional control and post-transcriptional GLD-1 regulation. We established a sensitive assay to quantify GLD-1 levels across an ∼35-cell diameter field, where distal germline stem cells differentiate proximally into meiotic prophase cells in the adult C. elegans hermaphrodite, and applied the approach to mutants in known or proposed GLD-1 regulators. In wild-type GLD-1 levels elevated ∼20-fold in a sigmoidal pattern. We found that two direct transcriptional targets of glp-1 signaling, lst-1 and sygl-1, were individually required for repression of GLD-1. We determined that lst-1 and sygl-1 act in the same genetic pathway as known GLD-1 translational repressor fbf-1, while lst-1 also acts in parallel to fbf-1, linking glp-1-mediated transcriptional control and post-transcriptional GLD-1 repression. Additionally, we estimated the position in wild-type gonads where germ cells irreversibly commit to meiotic development based on GLD-1 levels in worms where glp-1 activity was manipulated to cause an irreversible fate switch. Analysis of known repressors and activators, as well as modeling the sigmoidal accumulation pattern, indicated that regulation of GLD-1 levels is largely regional, which we integrated with the current view of germline stem cell differentiation. Copyright © 2016 by the Genetics Society of America.

  7. Atypical PKC and Notch Inhibition Differentially Modulate Cortical Interneuron Subclass Fate from Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    David J. Tischfield

    2017-05-01

    Full Text Available Recent studies indicate that the location of neurogenesis within the medial ganglionic eminence (MGE critically influences the fate determination of cortical interneuron subgroups, with parvalbumin (Pv interneurons originating from subventricular zone divisions and somatostatin (Sst interneurons primarily arising from apical divisions. The aPKC-CBP and Notch signaling pathways regulate the transition from apical to basal progenitor and their differentiation into post-mitotic neurons. We find that aPKC inhibition enhances intermediate neurogenesis from stem cell-derived MGE progenitors, resulting in a markedly increased ratio of Pv- to Sst-expressing interneurons. Conversely, inhibition of Notch signaling enriches for Sst subtypes at the expense of Pv fates. These findings confirm that the mode of neurogenesis influences the fate of MGE-derived interneurons and provide a means of further enrichment for the generation of specific interneuron subgroups from pluripotent stem cells.

  8. The SEL-12 presenilin mediates induction of the Caenorhabditis elegans uterine pi cell fate.

    Science.gov (United States)

    Cinar, H N; Sweet, K L; Hosemann, K E; Earley, K; Newman, A P

    2001-09-01

    During Caenorhabditis elegans hermaphrodite development, the anchor cell induces the vulva and the uterine pi cells whose daughters connect to the vulva, thereby organizing the uterine-vulval connection. Both the initial selection of a single anchor cell during the anchor cell vs. ventral uterine precursor cell decision and the subsequent induction of the pi cell fate by the anchor cell are mediated by the lin-12 gene. Members of the presenilin gene family can cause early onset Alzheimer's disease when mutated and are also required for LIN-12/Notch signaling during development. We have shown that, in C. elegans, mutation of the sel-12-encoded presenilin results in pi cell induction defects. By contrast, other lin-12-mediated cell fate decisions occur normally in sel-12 mutants due to the redundant function of a second C. elegans presenilin called HOP-1. We found that the sel-12 egg-laying defect was partially rescued by expression of the sel-12 gene in the pi cells. sel-12-mediated pi cell fate specification provides a useful system for the analysis of presenilin function at single cell resolution. Copyright 2001 Academic Press.

  9. Watch Out for the “Living Dead”: Cell-Free Enzymes and Their Fate

    Directory of Open Access Journals (Sweden)

    Federico Baltar

    2018-01-01

    Full Text Available Microbes are the engines driving biogeochemical cycles. Microbial extracellular enzymatic activities (EEAs are the “gatekeepers” of the carbon cycle. The total EEA is the sum of cell-bound (i.e., cell-attached, and dissolved (i.e., cell-free enzyme activities. Cell-free enzymes make up a substantial proportion (up to 100% of the total marine EEA. Although we are learning more about how microbial diversity and function (including total EEA will be affected by environmental changes, little is known about what factors control the importance of the abundant cell-free enzymes. Since cell-attached EEAs are linked to the cell, their fate will likely be linked to the factors controlling the cell’s fate. In contrast, cell-free enzymes belong to a kind of “living dead” realm because they are not attached to a living cell but still are able to perform their function away from the cell; and as such, the factors controlling their activity and fate might differ from those affecting cell-attached enzymes. This article aims to place cell-free EEA into the wider context of hydrolysis of organic matter, deal with recent studies assessing what controls the production, activity and lifetime of cell-free EEA, and what their fate might be in response to environmental stressors. This perspective article advocates the need to go “beyond the living things,” studying the response of cells/organisms to different stressors, but also to study cell-free enzymes, in order to fully constrain the future and evolution of marine biogeochemical cycles.

  10. Chapter 4. Stem cell proliferation versus meiotic fate decision in C. elegans

    Science.gov (United States)

    Schedl, Tim

    2013-01-01

    The C. elegans germ line has emerged as an important model for understanding how a stem cell population is maintained throughout the life of the animal while still producing the gametes necessary for propagation of the species. The stem cell population in the adult hermaphrodite is relatively large, with stem cells giving rise to daughters that appear intrinsically equivalent; however, some of the daughters retain the proliferative fate while others enter meiotic prophase. While machinery exists for cells to progress through the mitotic cell cycle and machinery exists for cells to progress through meiotic prophase, central to understanding germline development is identifying the genes and regulatory processes that determine whether the mitotic cell cycle or meiotic prophase machinery will be utilized; in other words, the genes that regulate the switch of germ cells from the proliferative stem cell fate to the meiotic development fate. Whether a germ cell self-renews or enters meiotic prophase is largely determined by its proximity to the distal tip cell (DTC), which is the somatic niche cell that caps the distal end of the gonad. Germ cells close to the DTC have high levels of GLP-1 Notch signaling, which promotes the proliferative fate, while cells further from the DTC have high activity levels of the GLD-1 and GLD-2 redundant RNA regulatory pathways, as well as a third uncharacterized pathway, each of which direct cells to enter meiotic prophase. Other factors and pathways modulate this core genetic pathway, or work in parallel to it, presumably to ensure that a tight balance is maintained between proliferation and meiotic entry. PMID:22872475

  11. Engineering Cell Instructive Materials To Control Cell Fate and Functions through Material Cues and Surface Patterning.

    Science.gov (United States)

    Ventre, Maurizio; Netti, Paolo A

    2016-06-22

    Mastering the interaction between cells and extracellular environment is a fundamental prerequisite in order to engineer functional biomaterial interfaces able to instruct cells with specific commands. Such advanced biomaterials might find relevant application in prosthesis design, tissue engineering, diagnostics and stem cell biology. Because of the highly complex, dynamic, and multifaceted context, a thorough understanding of the cell-material crosstalk has not been achieved yet; however, a variety of material features including biological cues, topography, and mechanical properties have been proved to impact the strength and the nature of the cell-material interaction, eventually affecting cell fate and functions. Although the nature of these three signals may appear very different, they are equated by their participation in the same material-cytoskeleton crosstalk pathway as they regulate cell adhesion events. In this work we present recent and relevant findings on the material-induced cell responses, with a particular emphasis on how the presentation of biochemical/biophysical signals modulates cell behavior. Finally, we summarize and discuss the literature data to draw out unifying elements concerning cell recognition of and reaction to signals displayed by material surfaces.

  12. Relationship between nanotopographical alignment and stem cell fate with live imaging and shape analysis

    OpenAIRE

    Newman, Peter; Galenano-Ni?o, Jorge Luis; Graney, Pamela; Razal, Joselito M.; Minett, Andrew I.; Ribas, Jo?o; Ovalle-Robles, Raquel; Biro, Mat?; Zreiqat, Hala

    2016-01-01

    The topography of a biomaterial regulates cellular interactions and determine stem cell fate. A complete understanding of how topographical properties affect cell behavior will allow the rational design of material surfaces that elicit specified biological functions once placed in the body. To this end, we fabricate substrates with aligned or randomly organized fibrous nanostructured topographies. Culturing adipose-derived stem cells (ASCs), we explore the dynamic relationship between the ali...

  13. Human mammary progenitor cell fate decisions are products of interactions with combinatorial microenvironments

    Energy Technology Data Exchange (ETDEWEB)

    LaBarge, Mark A; Nelson, Celeste M; Villadsen, Rene; Fridriksdottir, Agla; Ruth, Jason R; Stampfer, Martha R; Petersen, Ole W; Bissell, Mina J

    2008-09-19

    In adult tissues, multi-potent progenitor cells are some of the most primitive members of the developmental hierarchies that maintain homeostasis. That progenitors and their more mature progeny share identical genomes, suggests that fate decisions are directed by interactions with extrinsic soluble factors, ECM, and other cells, as well as physical properties of the ECM. To understand regulation of fate decisions, therefore, would require a means of understanding carefully choreographed combinatorial interactions. Here we used microenvironment protein microarrays to functionally identify combinations of cell-extrinsic mammary gland proteins and ECM molecules that imposed specific cell fates on bipotent human mammary progenitor cells. Micropatterned cell culture surfaces were fabricated to distinguish between the instructive effects of cell-cell versus cell-ECM interactions, as well as constellations of signaling molecules; and these were used in conjunction with physiologically relevant 3 dimensional human breast cultures. Both immortalized and primary human breast progenitors were analyzed. We report on the functional ability of those proteins of the mammary gland that maintain quiescence, maintain the progenitor state, and guide progenitor differentiation towards myoepithelial and luminal lineages.

  14. m6A RNA Modification Determines Cell Fate by Regulating mRNA Degradation.

    Science.gov (United States)

    Guo, Minjun; Liu, Xinhui; Zheng, Xiaotong; Huang, Yinghui; Chen, Xuechai

    2017-08-01

    Emerging evidence suggests that epitranscriptional modifications influence multiple cellular processes. N6-methyladenosine (m6A), as the most abundant reversible methylation of mRNA, has also been reported to play critical roles in modulating embryonic stem cell differentiation and somatic cell reprogramming by regulating gene expression. This review examined the characteristics of m6A, including the distribution profile and currently discovered "writer," "eraser," and "reader" proteins. Moreover, the hypothesis is proposed that m6A could influence cell fate determination, and the underlying mechanisms are due to the related mRNA degradation, causing weakening of previous cell characteristics and eventually leading them to develop into the reverse direction (pluripotency or differentiation state). Accordingly, m6A modifications presented its potential role in cell fate determination, which provides new insights into understanding the mechanisms of various diseases.

  15. Transcriptional control of stem cell fate by E2Fs and pocket proteins

    Science.gov (United States)

    Julian, Lisa M.; Blais, Alexandre

    2015-01-01

    E2F transcription factors and their regulatory partners, the pocket proteins (PPs), have emerged as essential regulators of stem cell fate control in a number of lineages. In mammals, this role extends from both pluripotent stem cells to those encompassing all embryonic germ layers, as well as extra-embryonic lineages. E2F/PP-mediated regulation of stem cell decisions is highly evolutionarily conserved, and is likely a pivotal biological mechanism underlying stem cell homeostasis. This has immense implications for organismal development, tissue maintenance, and regeneration. In this article, we discuss the roles of E2F factors and PPs in stem cell populations, focusing on mammalian systems. We discuss emerging findings that position the E2F and PP families as widespread and dynamic epigenetic regulators of cell fate decisions. Additionally, we focus on the ever expanding landscape of E2F/PP target genes, and explore the possibility that E2Fs are not simply regulators of general ‘multi-purpose’ cell fate genes but can execute tissue- and cell type-specific gene regulatory programs. PMID:25972892

  16. Transcriptional control of stem cell fate by E2Fs and Pocket Proteins

    Directory of Open Access Journals (Sweden)

    Lisa Marie Julian

    2015-04-01

    Full Text Available E2F transcription factors and their regulatory partners, the pocket proteins (PPs, have emerged as essential regulators of stem cell fate control in a number of lineages. In mammals, this role extends from both pluripotent stem cells to those encompassing all embryonic germ layers, as well as extra-embryonic lineages. E2F/PP-mediated regulation of stem cell decisions is highly evolutionarily conserved, and is likely a pivotal biological mechanism underlying stem cell homeostasis. This has immense implications for organismal development, tissue maintenance and regeneration. In this article, we discuss the roles of E2F factors and PPs in stem cell populations, focusing on mammalian systems. We discuss emerging findings that position the E2F and PP families as widespread and dynamic epigenetic regulators of cell fate decisions. Additionally, we focus on the ever expanding landscape of E2F/PP target genes, and explore the possibility that E2Fs are not simply regulators of general ‘multi-purpose’ cell fate genes but can execute tissue- and cell type-specific gene regulatory programs.

  17. Morphogen and community effects determine cell fates in response to BMP4 signaling in human embryonic stem cells.

    Science.gov (United States)

    Nemashkalo, Anastasiia; Ruzo, Albert; Heemskerk, Idse; Warmflash, Aryeh

    2017-09-01

    Paracrine signals maintain developmental states and create cell fate patterns in vivo and influence differentiation outcomes in human embryonic stem cells (hESCs) in vitro Systematic investigation of morphogen signaling is hampered by the difficulty of disentangling endogenous signaling from experimentally applied ligands. Here, we grow hESCs in micropatterned colonies of 1-8 cells ('µColonies') to quantitatively investigate paracrine signaling and the response to external stimuli. We examine BMP4-mediated differentiation in µColonies and standard culture conditions and find that in µColonies, above a threshold concentration, BMP4 gives rise to only a single cell fate, contrary to its role as a morphogen in other developmental systems. Under standard culture conditions BMP4 acts as a morphogen but this requires secondary signals and particular cell densities. We find that a 'community effect' enforces a common fate within µColonies, both in the state of pluripotency and when cells are differentiated, and that this effect allows a more precise response to external signals. Using live cell imaging to correlate signaling histories with cell fates, we demonstrate that interactions between neighbors result in sustained, homogenous signaling necessary for differentiation. © 2017. Published by The Company of Biologists Ltd.

  18. Stem cell fate determination during development and regeneration of ectodermal organs

    Directory of Open Access Journals (Sweden)

    Lucia eJimenez-Rojo

    2012-04-01

    Full Text Available The development of ectoderm-derived appendages results in a large variety of highly specialized organs such as hair follicles, mammary glands, salivary glands and teeth. Despite varying in number, shape and function, all these ectodermal organs develop through continuous and reciprocal epithelial-mesenchymal interactions, sharing common morphological and molecular features especially during their embryonic development. Diseases such as ectodermal dysplasias can affect simultaneously these organs, suggesting that they may arise from common multipotent precursors residing in the embryonic ectoderm. During embryogenesis, these putative ectodermal stem cells may adopt different fates and consequently be able to generate a variety of tissue-specific stem cells, which are the sources for the various cell lineages that form the diverse organs. The specification of those common epithelial precursors, as well as their further lineage commitment to tissue-specific stem cells, might be controlled by specific signals. It has been well documented that Notch, Wnt, bone morphogenetic protein (BMP and fibroblast growth factor (FGF signaling pathways regulate cell fate decisions during the various stages of ectodermal organ development. However, the in vivo spatial and temporal dynamics of these signaling pathways are not yet well understood. Improving the current knowledge on the mechanisms involved in stem cell fate determination during organogenesis and homeostasis of ectodermal organs is crucial to develop effective stem cell-based therapies in order to regenerate or replace pathological and damaged tissues.

  19. Control of epithelial cell structure and developmental fate: lessons from Helicobacter pylori.

    Science.gov (United States)

    Mimuro, Hitomi; Berg, Douglas E; Sasakawa, Chihiro

    2008-06-01

    Valuable insights into eukaryotic regulatory circuits can emerge from studying interactions of bacterial pathogens such as Helicobacter pylori with host tissues. H. pylori uses a type IV secretion system (T4SS) to deliver its CagA virulence protein to epithelial cells, where much of it becomes phosphorylated. CagA's phosphorylated and non-phosphorylated forms each interact with host regulatory proteins to alter cell structure and cell fate. Kwok and colleagues showed that CagA destined for phosphorylation is delivered using host integrin as receptor and H. pylori's CagL protein as an integrin-specific adhesin, and that CagL-integrin-binding activates the kinase cascade responsible for CagA phosphorylation. This research contributes to understanding infectious disease and the control of cell fates.

  20. Single-cell analysis of the fate of c-kit-positive bone marrow cells

    Science.gov (United States)

    Czarna, Anna; Sanada, Fumihiro; Matsuda, Alex; Kim, Junghyun; Signore, Sergio; Pereira, João D.; Sorrentino, Andrea; Kannappan, Ramaswamy; Cannatà, Antonio; Hosoda, Toru; Rota, Marcello; Crea, Filippo; Anversa, Piero; Leri, Annarosa

    2017-10-01

    The plasticity of c-kit-positive bone marrow cells (c-kit-BMCs) in tissues different from their organ of origin remains unclear. We tested the hypothesis that c-kit-BMCs are functionally heterogeneous and only a subgroup of these cells possesses cardiomyogenic potential. Population-based assays fall short of identifying the properties of individual stem cells, imposing on us the introduction of single cell-based approaches to track the fate of c-kit-BMCs in the injured heart; they included viral gene-tagging, multicolor clonal-marking and transcriptional profiling. Based on these strategies, we report that single mouse c-kit-BMCs expand clonally within the infarcted myocardium and differentiate into specialized cardiac cells. Newly-formed cardiomyocytes, endothelial cells, fibroblasts and c-kit-BMCs showed in their genome common sites of viral integration, providing strong evidence in favor of the plasticity of a subset of BMCs expressing the c-kit receptor. Similarly, individual c-kit-BMCs, which were infected with multicolor reporters and injected in infarcted hearts, formed cardiomyocytes and vascular cells organized in clusters of similarly colored cells. The uniform distribution of fluorescent proteins in groups of specialized cells documented the polyclonal nature of myocardial regeneration. The transcriptional profile of myogenic c-kit-BMCs and whole c-kit-BMCs was defined by RNA sequencing. Genes relevant for engraftment, survival, migration, and differentiation were enriched in myogenic c-kit-BMCs, a cell subtype which could not be assigned to a specific hematopoietic lineage. Collectively, our findings demonstrate that the bone marrow comprises a category of cardiomyogenic, vasculogenic and/or fibrogenic c-kit-positive cells and a category of c-kit-positive cells that retains an undifferentiated state within the damaged heart.

  1. Multidimensional nanomaterials for the control of stem cell fate

    Science.gov (United States)

    Chueng, Sy-Tsong Dean; Yang, Letao; Zhang, Yixiao; Lee, Ki-Bum

    2016-09-01

    Current stem cell therapy suffers low efficiency in giving rise to differentiated cell lineages, which can replace the original damaged cells. Nanomaterials, on the other hand, provide unique physical size, surface chemistry, conductivity, and topographical microenvironment to regulate stem cell differentiation through multidimensional approaches to facilitate gene delivery, cell-cell, and cell-ECM interactions. In this review, nanomaterials are demonstrated to work both alone and synergistically to guide selective stem cell differentiation. From three different nanotechnology families, three approaches are shown: (1) soluble microenvironmental factors; (2) insoluble physical microenvironment; and (3) nano-topographical features. As regenerative medicine is heavily invested in effective stem cell therapy, this review is inspired to generate discussions in the potential clinical applications of multi-dimensional nanomaterials.

  2. The Fate of Intrapleurally Injected Bone Marrow-Derived Stem Cells in Mice with Pleural Mesothelioma

    Science.gov (United States)

    2012-12-01

    11-1-0574 TITLE: The Fate of Intrapleurally Injected Bone Marrow-Derived Stem Cells in Mice with Pleural Mesothelioma PRINCIPAL...Mice with Pleural Mesothelioma 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-11-1-0574 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Jonathan M...stem cells (BMSCs) as potential therapeutics against malignant mesothelioma (MM). Our over-arching goal was to determine whether fluorescently

  3. Proliferation and cell fate establishment during Arabidopsis male gametogenesis depends on the Retinoblastoma protein

    Science.gov (United States)

    Chen, Zhong; Hafidh, Said; Poh, Shi Hui; Twell, David; Berger, Frederic

    2009-01-01

    The Retinoblastoma (Rb) protein is a conserved repressor of cell proliferation. In animals and plants, deregulation of Rb protein causes hyperproliferation and perturbs cell differentiation to various degrees. However, the primary developmental impact of the loss of Rb protein has remained unclear. In this study we investigated the direct consequences of Rb protein knockout in the Arabidopsis male germline using cytological and molecular markers. The Arabidopsis germ line derives from the unequal division of the microspore, producing a small germ cell and a large terminally differentiated vegetative cell. A single division of the germ cell produces the 2 sperm cells. We observed that the loss of Rb protein does not have a major impact on microspore division but causes limited hyperproliferation of the vegetative cell and, to a lesser degree, of the sperm cells. In addition, cell fate is perturbed in a fraction of Rb-defective vegetative cells. These defects are rescued by preventing cell proliferation arising from down-regulation of cyclin-dependent kinase A1. Our results indicate that hyperproliferation caused by the loss of Rb protein prevents or delays cell determination during plant male gametogenesis, providing further evidence for a direct link between fate determination and cell proliferation. PMID:19359496

  4. Live cell imaging reveals marked variability in myoblast proliferation and fate

    Science.gov (United States)

    2013-01-01

    Background During the process of muscle regeneration, activated stem cells termed satellite cells proliferate, and then differentiate to form new myofibers that restore the injured area. Yet not all satellite cells contribute to muscle repair. Some continue to proliferate, others die, and others become quiescent and are available for regeneration following subsequent injury. The mechanisms that regulate the adoption of different cell fates in a muscle cell precursor population remain unclear. Methods We have used live cell imaging and lineage tracing to study cell fate in the C2 myoblast line. Results Analyzing the behavior of individual myoblasts revealed marked variability in both cell cycle duration and viability, but similarities between cells derived from the same parental lineage. As a consequence, lineage sizes and outcomes differed dramatically, and individual lineages made uneven contributions toward the terminally differentiated population. Thus, the cohort of myoblasts undergoing differentiation at the end of an experiment differed dramatically from the lineages present at the beginning. Treatment with IGF-I increased myoblast number by maintaining viability and by stimulating a fraction of cells to complete one additional cell cycle in differentiation medium, and as a consequence reduced the variability of the terminal population compared with controls. Conclusion Our results reveal that heterogeneity of responses to external cues is an intrinsic property of cultured myoblasts that may be explained in part by parental lineage, and demonstrate the power of live cell imaging for understanding how muscle differentiation is regulated. PMID:23638706

  5. Brg1 Determines Urothelial Cell Fate during Ureter Development

    Science.gov (United States)

    Weiss, Robert M.; Guo, Songshan; Shan, Alan; Shi, Hongmei; Romano, Rose-Anne; Sinha, Satrajit; Cantley, Lloyd G.

    2013-01-01

    Developing and adult ureters express the epigenetic regulator Brg1, but the role of Brg1 in ureter development is not well understood. We conditionally ablated Brg1 in the developing ureter using Hoxb7-Cre and found that Brg1 expression is upstream of p63, Pparγ, and sonic hedgehog (Shh) expression in the ureteral epithelium. In addition, epithelial stratification in the basal cells required Brg1-dependent p63 expression, whereas terminal differentiation of the umbrella cells required Brg1-dependent Pparγ expression. Furthermore, the loss of ureteric Brg1 resulted in failure of Shh expression, which correlated with reduced smooth muscle cell development and hydroureter. Taken together, we conclude that Brg1 expression unifies three aspects of ureter development: maintenance of the basal cell population, guidance for terminal differentiation of urothelial cells, and proper investment of ureteral smooth muscle cells. PMID:23449535

  6. IgH isotype-specific B cell receptor expression influences B cell fate.

    Science.gov (United States)

    Tong, Pei; Granato, Alessandra; Zuo, Teng; Chaudhary, Neha; Zuiani, Adam; Han, Seung Seok; Donthula, Rakesh; Shrestha, Akritee; Sen, Debattama; Magee, Jennifer M; Gallagher, Michael P; van der Poel, Cees E; Carroll, Michael C; Wesemann, Duane R

    2017-10-03

    Ig heavy chain (IgH) isotypes (e.g., IgM, IgG, and IgE) are generated as secreted/soluble antibodies (sIg) or as membrane-bound (mIg) B cell receptors (BCRs) through alternative RNA splicing. IgH isotype dictates soluble antibody function, but how mIg isotype influences B cell behavior is not well defined. We examined IgH isotype-specific BCR function by analyzing naturally switched B cells from wild-type mice, as well as by engineering polyclonal Ighγ1/γ1 and Ighε/ε mice, which initially produce IgG1 or IgE from their respective native genomic configurations. We found that B cells from wild-type mice, as well as Ighγ1/γ1 and Ighε/ε mice, produce transcripts that generate IgM, IgG1, and IgE in an alternative splice form bias hierarchy, regardless of cell stage. In this regard, we found that mIgμ > mIgγ1 > mIgε, and that these BCR expression differences influence respective developmental fitness. Restrained B cell development from Ighγ1/γ1 and Ighε/ε mice was proportional to sIg/mIg ratios and was rescued by enforced expression of the respective mIgs. In addition, artificially enhancing BCR signal strength permitted IgE+ memory B cells-which essentially do not exist under normal conditions-to provide long-lived memory function, suggesting that quantitative BCR signal weakness contributes to restraint of IgE B cell responses. Our results indicate that IgH isotype-specific mIg/BCR dosage may play a larger role in B cell fate than previously anticipated.

  7. FGF/MAPK signaling sets the switching threshold of a bistable circuit controlling cell fate decisions in embryonic stem cells.

    Science.gov (United States)

    Schröter, Christian; Rué, Pau; Mackenzie, Jonathan Peter; Martinez Arias, Alfonso

    2015-12-15

    Intracellular transcriptional regulators and extracellular signaling pathways together regulate the allocation of cell fates during development, but how their molecular activities are integrated to establish the correct proportions of cells with particular fates is not known. Here we study this question in the context of the decision between the epiblast (Epi) and the primitive endoderm (PrE) fate that occurs in the mammalian preimplantation embryo. Using an embryonic stem cell (ESC) model, we discover two successive functions of FGF/MAPK signaling in this decision. First, the pathway needs to be inhibited to make the PrE-like gene expression program accessible for activation by GATA transcription factors in ESCs. In a second step, MAPK signaling levels determine the threshold concentration of GATA factors required for PrE-like differentiation, and thereby control the proportion of cells differentiating along this lineage. Our findings can be explained by a simple mutual repression circuit modulated by FGF/MAPK signaling. This might be a general network architecture to integrate the activity of signal transduction pathways and transcriptional regulators, and serve to balance proportions of cell fates in several contexts. © 2015. Published by The Company of Biologists Ltd.

  8. The sox family of transcription factors: versatile regulators of stem and progenitor cell fate.

    Science.gov (United States)

    Sarkar, Abby; Hochedlinger, Konrad

    2013-01-03

    Sox family transcription factors are well-established regulators of cell fate decisions during development. Accumulating evidence documents that they play additional roles in adult tissue homeostasis and regeneration. Remarkably, forced expression of Sox factors, in combination with other synergistic factors, reprograms differentiated cells into somatic or pluripotent stem cells. Dysregulation of Sox factors has been further implicated in diseases including cancer. Here, we review molecular and functional evidence linking Sox proteins with stem cell biology, cellular reprogramming, and disease with an emphasis on Sox2. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Immunomodulatory Factors Control the Fate of Melanoma Tumor Initiating Cells

    NARCIS (Netherlands)

    Tuccitto, A.; Tazzari, M.; Beretta, V.; Rini, F.; Miranda, C.; Greco, A; Santinami, M.; Patuzzo, R.; Vergani, B.; Villa, A.; Manenti, G.; Cleris, L.; Giardiello, D.; Alison, M.; Rivoltini, L.; Castelli, C.; Perego, M.

    2016-01-01

    Melanoma is a highly heterogeneous tumor for which recent evidence supports a model of dynamic stemness. Melanoma cells might temporally acquire tumor-initiating properties or switch from a status of tumor-initiating cells (TICs) to a more differentiated one depending on the tumor context. However,

  10. Mitochondrial Dynamics Controls T Cell Fate through Metabolic Programming

    NARCIS (Netherlands)

    Buck, Michael D.; O'Sullivan, David; Klein Geltink, Ramon I.; Curtis, Jonathan D.; Chang, Chih-Hao; Sanin, David E.; Qiu, Jing; Kretz, Oliver; Braas, Daniel; van der Windt, Gerritje J. W.; Chen, Qiongyu; Huang, Stanley Ching-Cheng; O'Neill, Christina M.; Edelson, Brian T.; Pearce, Edward J.; Sesaki, Hiromi; Huber, Tobias B.; Rambold, Angelika S.; Pearce, Erika L.

    2016-01-01

    Activated effector T (TE) cells augment anabolic pathways of metabolism, such as aerobic glycolysis, while memory T (TM) cells engage catabolic pathways, like fatty acid oxidation (FAO). However, signals that drive these differences remain unclear. Mitochondria are metabolic organelles that actively

  11. EBV and Apoptosis: The Viral Master Regulator of Cell Fate?

    Science.gov (United States)

    Kelly, Gemma L.

    2017-01-01

    Epstein–Barr virus (EBV) was first discovered in cells from a patient with Burkitt lymphoma (BL), and is now known to be a contributory factor in 1–2% of all cancers, for which there are as yet, no EBV-targeted therapies available. Like other herpesviruses, EBV adopts a persistent latent infection in vivo and only rarely reactivates into replicative lytic cycle. Although latency is associated with restricted patterns of gene expression, genes are never expressed in isolation; always in groups. Here, we discuss (1) the ways in which the latent genes of EBV are known to modulate cell death, (2) how these mechanisms relate to growth transformation and lymphomagenesis, and (3) how EBV genes cooperate to coordinately regulate key cell death pathways in BL and lymphoblastoid cell lines (LCLs). Since manipulation of the cell death machinery is critical in EBV pathogenesis, understanding the mechanisms that underpin EBV regulation of apoptosis therefore provides opportunities for novel therapeutic interventions. PMID:29137176

  12. Sox5 functions as a fate switch in medaka pigment cell development.

    Directory of Open Access Journals (Sweden)

    Yusuke Nagao

    2014-04-01

    Full Text Available Mechanisms generating diverse cell types from multipotent progenitors are crucial for normal development. Neural crest cells (NCCs are multipotent stem cells that give rise to numerous cell-types, including pigment cells. Medaka has four types of NCC-derived pigment cells (xanthophores, leucophores, melanophores and iridophores, making medaka pigment cell development an excellent model for studying the mechanisms controlling specification of distinct cell types from a multipotent progenitor. Medaka many leucophores-3 (ml-3 mutant embryos exhibit a unique phenotype characterized by excessive formation of leucophores and absence of xanthophores. We show that ml-3 encodes sox5, which is expressed in premigratory NCCs and differentiating xanthophores. Cell transplantation studies reveal a cell-autonomous role of sox5 in the xanthophore lineage. pax7a is expressed in NCCs and required for both xanthophore and leucophore lineages; we demonstrate that Sox5 functions downstream of Pax7a. We propose a model in which multipotent NCCs first give rise to pax7a-positive partially fate-restricted intermediate progenitors for xanthophores and leucophores; some of these progenitors then express sox5, and as a result of Sox5 action develop into xanthophores. Our results provide the first demonstration that Sox5 can function as a molecular switch driving specification of a specific cell-fate (xanthophore from a partially-restricted, but still multipotent, progenitor (the shared xanthophore-leucophore progenitor.

  13. Matrix mechanics and fluid shear stress control stem cells fate in three dimensional microenvironment.

    Science.gov (United States)

    Chen, Guobao; Lv, Yonggang; Guo, Pan; Lin, Chongwen; Zhang, Xiaomei; Yang, Li; Xu, Zhiling

    2013-07-01

    Stem cells have the ability to self-renew and to differentiate into multiple mature cell types during early life and growth. Stem cells adhesion, proliferation, migration and differentiation are affected by biochemical, mechanical and physical surface properties of the surrounding matrix in which stem cells reside and stem cells can sensitively feel and respond to the microenvironment of this matrix. More and more researches have proven that three dimensional (3D) culture can reduce the gap between cell culture and physiological environment where cells always live in vivo. This review summarized recent findings on the studies of matrix mechanics that control stem cells (primarily mesenchymal stem cells (MSCs)) fate in 3D environment, including matrix stiffness and extracellular matrix (ECM) stiffness. Considering the exchange of oxygen and nutrients in 3D culture, the effect of fluid shear stress (FSS) on fate decision of stem cells was also discussed in detail. Further, the difference of MSCs response to matrix stiffness between two dimensional (2D) and 3D conditions was compared. Finally, the mechanism of mechanotransduction of stem cells activated by matrix mechanics and FSS in 3D culture was briefly pointed out.

  14. Cap-independent translation by DAP5 controls cell fate decisions in human embryonic stem cells

    Science.gov (United States)

    Yoffe, Yael; David, Maya; Kalaora, Rinat; Povodovski, Lital; Friedlander, Gilgi; Feldmesser, Ester; Ainbinder, Elena; Saada, Ann; Bialik, Shani; Kimchi, Adi

    2016-01-01

    Multiple transcriptional and epigenetic changes drive differentiation of embryonic stem cells (ESCs). This study unveils an additional level of gene expression regulation involving noncanonical, cap-independent translation of a select group of mRNAs. This is driven by death-associated protein 5 (DAP5/eIF4G2/NAT1), a translation initiation factor mediating IRES-dependent translation. We found that the DAP5 knockdown from human ESCs (hESCs) resulted in persistence of pluripotent gene expression, delayed induction of differentiation-associated genes in different cell lineages, and defective embryoid body formation. The latter involved improper cellular organization, lack of cavitation, and enhanced mislocalized apoptosis. RNA sequencing of polysome-associated mRNAs identified candidates with reduced translation efficiency in DAP5-depleted hESCs. These were enriched in mitochondrial proteins involved in oxidative respiration, a pathway essential for differentiation, the significance of which was confirmed by the aberrant mitochondrial morphology and decreased oxidative respiratory activity in DAP5 knockdown cells. Further analysis identified the chromatin modifier HMGN3 as a cap-independent DAP5 translation target whose knockdown resulted in defective differentiation. Thus, DAP5-mediated translation of a specific set of proteins is critical for the transition from pluripotency to differentiation, highlighting the importance of cap-independent translation in stem cell fate decisions. PMID:27664238

  15. Prolonged Mitosis of Neural Progenitors Alters Cell Fate in the Developing Brain.

    Science.gov (United States)

    Pilaz, Louis-Jan; McMahon, John J; Miller, Emily E; Lennox, Ashley L; Suzuki, Aussie; Salmon, Edward; Silver, Debra L

    2016-01-06

    Embryonic neocortical development depends on balanced production of progenitors and neurons. Genetic mutations disrupting progenitor mitosis frequently impair neurogenesis; however, the link between altered mitosis and cell fate remains poorly understood. Here we demonstrate that prolonged mitosis of radial glial progenitors directly alters neuronal fate specification and progeny viability. Live imaging of progenitors from a neurogenesis mutant, Magoh(+/-), reveals that mitotic delay significantly correlates with preferential production of neurons instead of progenitors, as well as apoptotic progeny. Independently, two pharmacological approaches reveal a causal relationship between mitotic delay and progeny fate. As mitotic duration increases, progenitors produce substantially more apoptotic progeny or neurons. We show that apoptosis, but not differentiation, is p53 dependent, demonstrating that these are distinct outcomes of mitotic delay. Together our findings reveal that prolonged mitosis is sufficient to alter fates of radial glia progeny and define a new paradigm to understand how mitosis perturbations underlie brain size disorders such as microcephaly. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Zeb2 Regulates Cell Fate at the Exit from Epiblast State in Mouse Embryonic Stem Cells.

    Science.gov (United States)

    Stryjewska, Agata; Dries, Ruben; Pieters, Tim; Verstappen, Griet; Conidi, Andrea; Coddens, Kathleen; Francis, Annick; Umans, Lieve; van IJcken, Wilfred F J; Berx, Geert; van Grunsven, Leo A; Grosveld, Frank G; Goossens, Steven; Haigh, Jody J; Huylebroeck, Danny

    2017-03-01

    In human embryonic stem cells (ESCs) the transcription factor Zeb2 regulates neuroectoderm versus mesendoderm formation, but it is unclear how Zeb2 affects the global transcriptional regulatory network in these cell-fate decisions. We generated Zeb2 knockout (KO) mouse ESCs, subjected them as embryoid bodies (EBs) to neural and general differentiation and carried out temporal RNA-sequencing (RNA-seq) and reduced representation bisulfite sequencing (RRBS) analysis in neural differentiation. This shows that Zeb2 acts preferentially as a transcriptional repressor associated with developmental progression and that Zeb2 KO ESCs can exit from their naïve state. However, most cells in these EBs stall in an early epiblast-like state and are impaired in both neural and mesendodermal differentiation. Genes involved in pluripotency, epithelial-to-mesenchymal transition (EMT), and DNA-(de)methylation, including Tet1, are deregulated in the absence of Zeb2. The observed elevated Tet1 levels in the mutant cells and the knowledge of previously mapped Tet1-binding sites correlate with loss-of-methylation in neural-stimulating conditions, however, after the cells initially acquired the correct DNA-methyl marks. Interestingly, cells from such Zeb2 KO EBs maintain the ability to re-adapt to 2i + LIF conditions even after prolonged differentiation, while knockdown of Tet1 partially rescues their impaired differentiation. Hence, in addition to its role in EMT, Zeb2 is critical in ESCs for exit from the epiblast state, and links the pluripotency network and DNA-methylation with irreversible commitment to differentiation. Stem Cells 2017;35:611-625. © 2016 The Authors Stem Cells published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

  17. Concentration Sensing by the Moving Nucleus in Cell Fate Determination: A Computational Analysis.

    Directory of Open Access Journals (Sweden)

    Varun Aggarwal

    Full Text Available During development of the vertebrate neuroepithelium, the nucleus in neural progenitor cells (NPCs moves from the apex toward the base and returns to the apex (called interkinetic nuclear migration at which point the cell divides. The fate of the resulting daughter cells is thought to depend on the sampling by the moving nucleus of a spatial concentration profile of the cytoplasmic Notch intracellular domain (NICD. However, the nucleus executes complex stochastic motions including random waiting and back and forth motions, which can expose the nucleus to randomly varying levels of cytoplasmic NICD. How nuclear position can determine daughter cell fate despite the stochastic nature of nuclear migration is not clear. Here we derived a mathematical model for reaction, diffusion, and nuclear accumulation of NICD in NPCs during interkinetic nuclear migration (INM. Using experimentally measured trajectory-dependent probabilities of nuclear turning, nuclear waiting times and average nuclear speeds in NPCs in the developing zebrafish retina, we performed stochastic simulations to compute the nuclear trajectory-dependent probabilities of NPC differentiation. Comparison with experimentally measured nuclear NICD concentrations and trajectory-dependent probabilities of differentiation allowed estimation of the NICD cytoplasmic gradient. Spatially polarized production of NICD, rapid NICD cytoplasmic consumption and the time-averaging effect of nuclear import/export kinetics are sufficient to explain the experimentally observed differentiation probabilities. Our computational studies lend quantitative support to the feasibility of the nuclear concentration-sensing mechanism for NPC fate determination in zebrafish retina.

  18. Temporal transcriptional profiling of somatic and germ cells reveals biased lineage priming of sexual fate in the fetal mouse gonad.

    Directory of Open Access Journals (Sweden)

    Samantha A Jameson

    Full Text Available The divergence of distinct cell populations from multipotent progenitors is poorly understood, particularly in vivo. The gonad is an ideal place to study this process, because it originates as a bipotential primordium where multiple distinct lineages acquire sex-specific fates as the organ differentiates as a testis or an ovary. To gain a more detailed understanding of the process of gonadal differentiation at the level of the individual cell populations, we conducted microarrays on sorted cells from XX and XY mouse gonads at three time points spanning the period when the gonadal cells transition from sexually undifferentiated progenitors to their respective sex-specific fates. We analyzed supporting cells, interstitial/stromal cells, germ cells, and endothelial cells. This work identified genes specifically depleted and enriched in each lineage as it underwent sex-specific differentiation. We determined that the sexually undifferentiated germ cell and supporting cell progenitors showed lineage priming. We found that germ cell progenitors were primed with a bias toward the male fate. In contrast, supporting cells were primed with a female bias, indicative of the robust repression program involved in the commitment to XY supporting cell fate. This study provides a molecular explanation reconciling the female default and balanced models of sex determination and represents a rich resource for the field. More importantly, it yields new insights into the mechanisms by which different cell types in a single organ adopt their respective fates.

  19. Differential levels of Neurod establish zebrafish endocrine pancreas cell fates

    National Research Council Canada - National Science Library

    Dalgin, Gökhan; Prince, Victoria E

    2015-01-01

    .... Differentiation of appropriate numbers of each hormone-expressing endocrine cell type is essential for the normal development of the pancreas and ultimately for effective maintenance of blood glucose levels...

  20. Tissue landscape alters adjacent cell fates during Drosophila egg development.

    Science.gov (United States)

    Manning, Lathiena A; Weideman, Ann Marie; Peercy, Bradford E; Starz-Gaiano, Michelle

    2015-06-17

    Extracellular signalling molecules control many biological processes, but the influence of tissue architecture on the local concentrations of these factors is unclear. Here we examine this issue in the Drosophila egg chamber, where two anterior cells secrete Unpaired (Upd) to activate Signal transducer and activator of transcription (STAT) signalling in the epithelium. High STAT signalling promotes cell motility. Genetic analysis shows that all cells near the Upd source can respond. However, using upright imaging, we show surprising asymmetries in STAT activation patterns, suggesting that some cells experience different Upd levels than predicted by their location. We develop a three-dimensional mathematical model to characterize the spatio-temporal distribution of the activator. Simulations show that irregular tissue domains can produce asymmetric distributions of Upd, consistent with results in vivo. Mutant analysis substantiates this idea. We conclude that cellular landscape can heavily influence the effect of diffusible activators and should be more widely considered.

  1. Noise in Gene Expression Determines Cell Fate in Bacillus subtilis

    National Research Council Canada - National Science Library

    Hédia Maamar; Arjun Raj; David Dubnau

    2007-01-01

    .... In Bacillus subtilis, noise in ComK, the protein that regulates competence for DNA uptake, is thought to cause cells to transition to the competent state in which genes encoding DNA uptake proteins are expressed...

  2. Transcription factors regulating B cell fate in the germinal centre.

    Science.gov (United States)

    Recaldin, T; Fear, D J

    2016-01-01

    Diversification of the antibody repertoire is essential for the normal operation of the vertebrate adaptive immune system. Following antigen encounter, B cells are activated, proliferate rapidly and undergo two diversification events; somatic hypermutation (followed by selection), which enhances the affinity of the antibody for its cognate antigen, and class-switch recombination, which alters the effector functions of the antibody to adapt the response to the challenge faced. B cells must then differentiate into antibody-secreting plasma cells or long-lived memory B cells. These activities take place in specialized immunological environments called germinal centres, usually located in the secondary lymphoid organs. To complete the germinal centre activities successfully, a B cell adopts a transcriptional programme that allows it to migrate to specific sites within the germinal centre, proliferate, modify its DNA recombination and repair pathways, alter its apoptotic potential and finally undergo terminal differentiation. To co-ordinate these processes, B cells employ a number of 'master regulator' transcription factors which mediate wholesale transcriptomic changes. These master transcription factors are mutually antagonistic and form a complex regulatory network to maintain distinct gene expression programs. Within this network, multiple points of positive and negative feedback ensure the expression of the 'master regulators', augmented by a number of 'secondary' factors that reinforce these networks and sense the progress of the immune response. In this review we will discuss the different activities B cells must undertake to mount a successful T cell-dependent immune response and describe how a regulatory network of transcription factors controls these processes. © 2015 British Society for Immunology.

  3. Programming cell fate on bio-functionalized silicon.

    Science.gov (United States)

    Premnath, Priyatha; Tan, Bo; Venkatakrishnan, Krishnan

    2015-04-01

    Controlling the growth of cells on the surface of silicon without an additive layer or topographical modification is unexplored. This research article delineates the discovery of unique properties of a bio-functionalized silicon substrate, programmed to repel or control cells, generated by ultrafast femtosecond pulse interaction with silicon. Remarkably, bio-functionalization in any shape or size without change in topology or morphology is observed indicating only sub-surface phase transformations. Material characterization reveals the presence of a unique mixture of phases of SiO2 and Si. Consequently, these variations in phase alter the physicochemical characteristics on the surface of silicon resulting in its bio-functionalization. The culture of mouse embryonic fibroblasts shows unique adhesion characteristics on these bio-functionalized silicon surfaces that include cell controlling, cell trapping, and cell shaping. Furthermore, the directionality of fibroblasts is restrained parallel to bio-functionalized zones as evidenced by changes in cytoskeleton. The controlling of proliferation, migration and adhesion of cells is attributed to unique phase bio-functionalization. This method presents considerable promise in a myriad of applications such as tissue engineering, MEMS, and lab-on-a-chip devices. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Route Choice Estimation Using Cell Phone Data

    Directory of Open Access Journals (Sweden)

    Taghipour Homa

    2016-01-01

    Full Text Available Nowadays development of cell phone network provides huge and ubiquitous data, with wide application in transportation science. One of the most important advantages of these kinds of data is enabling the process of collecting information without any active users’ interference. A big data set consisting of 300,000 cell phone users’ information in Shiraz are studied. This data set includes spatiotemporal information of travelers for every 5 minutes in a time span of 40 hours in two consecutive days. The spatial part of each user’s information contains the position of the BTS (Base Transceiver Station to which his cell phone is currently connected. Due to the existence of outliers, it is necessary to smooth the data initially. One of the main reasons of errors in the data set is ping pong handover, which leads to false transitions and must be eliminated. After the data preparation, stay locations are determined for each user and a trajectory for each pair of origin and destination is estimated. At this step based on network information of the city, a method to match trajectories with the network map is applied. Finally the obtained results indicate whether travelers choose the shortest path or other possible alternatives.

  5. Union is strength: matrix elasticity and microenvironmental factors codetermine stem cell differentiation fate.

    Science.gov (United States)

    Lv, Hongwei; Li, Lisha; Zhang, Yin; Chen, Zhishen; Sun, Meiyu; Xu, Tiankai; Tian, Licheng; Lu, Man; Ren, Min; Liu, Yuanyuan; Li, Yulin

    2015-09-01

    Stem cells are an attractive cellular source for regenerative medicine and tissue engineering applications due to their multipotency. Although the elasticity of the extracellular matrix (ECM) has been shown to have crucial impacts in directing stem cell differentiation, it is not the only contributing factor. Many researchers have recently attempted to design microenvironments that mimic the stem cell niche with combinations of ECM elasticity and other cues, such as ECM physical properties, soluble biochemical factors and cell-cell interactions, thereby driving cells towards their preferred lineages. Here, we briefly discuss the effect of matrix elasticity on stem cell lineage specification and then summarize recent advances in the study of the combined effects of ECM elasticity and other cues on the differentiation of stem cells, focusing on two aspects: biophysical and biochemical factors. In the future, biomedical scientists will continue investigating the union strength of matrix elasticity and microenvironmental cues for manipulating stem cell fates.

  6. Fate of cerium dioxide nanoparticles in endothelial cells: exocytosis

    Science.gov (United States)

    Strobel, Claudia; Oehring, Hartmut; Herrmann, Rudolf; Förster, Martin; Reller, Armin; Hilger, Ingrid

    2015-05-01

    Although cytotoxicity and endocytosis of nanoparticles have been the subject of numerous studies, investigations regarding exocytosis as an important mechanism to reduce intracellular nanoparticle accumulation are rather rare and there is a distinct lack of knowledge. The current study investigated the behavior of human microvascular endothelial cells to exocytose cerium dioxide (CeO2) nanoparticles (18.8 nm) by utilization of specific inhibitors [brefeldin A; nocodazole; methyl-β-cyclodextrin (MβcD)] and different analytical methods (flow cytometry, transmission electron microscopy, inductively coupled plasma mass spectrometry). Overall, it was found that endothelial cells were able to release CeO2 nanoparticles via exocytosis after the migration of nanoparticle containing endosomes toward the plasma membrane. The exocytosis process occurred mainly by fusion of vesicular membranes with plasma membrane resulting in the discharge of vesicular content to extracellular environment. Nevertheless, it seems to be likely that nanoparticles present in the cytosol could leave the cells in a direct manner. MβcD treatment led to the strongest inhibition of the nanoparticle exocytosis indicating a significant role of the plasma membrane cholesterol content in the exocytosis process. Brefeldin A (inhibitor of Golgi-to-cell-surface-transport) caused a higher inhibitory effect on exocytosis than nocodazole (inhibitor of microtubules). Thus, the transfer from distal Golgi compartments to the cell surface influenced the exocytosis process of the CeO2 nanoparticles more than the microtubule-associated transport. In conclusion, endothelial cells, which came in contact with nanoparticles, e.g., after intravenously applied nano-based drugs, can regulate their intracellular nanoparticle amount, which is necessary to avoid adverse nanoparticle effects on cells.

  7. Functionalized scaffolds to control dental pulp stem cell fate.

    Science.gov (United States)

    Piva, Evandro; Silva, Adriana F; Nör, Jacques E

    2014-04-01

    Emerging understanding about interactions between stem cells, scaffolds, and morphogenic factors has accelerated translational research in the field of dental pulp tissue engineering. Dental pulp stem cells constitute a subpopulation of cells endowed with self-renewal and multipotency. Dental pulp stem cells seeded in biodegradable scaffolds and exposed to dentin-derived morphogenic factors give rise to a pulplike tissue capable of generating new dentin. Notably, dentin-derived proteins are sufficient to induce dental pulp stem cell differentiation into odontoblasts. Ongoing work is focused on developing ways of mobilizing dentin-derived proteins and disinfecting the root canal of necrotic teeth without compromising the morphogenic potential of these signaling molecules. On the other hand, dentin by itself does not appear to be capable of inducing endothelial differentiation of dental pulp stem cells despite the well-known presence of angiogenic factors in dentin. This is particularly relevant in the context of dental pulp tissue engineering in full root canals in which access to blood supply is limited to the apical foramina. To address this challenge, scientists are looking at ways to use the scaffold as a controlled-release device for angiogenic factors. The aim of this article was to present and discuss current strategies to functionalize injectable scaffolds and customize them for dental pulp tissue engineering. The long-term goal of this work is to develop stem cell-based therapies that enable the engineering of functional dental pulps capable of generating new tubular dentin in humans. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  8. Fate of cerium dioxide nanoparticles in endothelial cells: exocytosis

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Claudia, E-mail: Claudia.Strobel@med.uni-jena.de [Jena University Hospital – Friedrich Schiller University Jena, Department of Experimental Radiology, Institute of Diagnostic and Interventional Radiology (Germany); Oehring, Hartmut [Jena University Hospital – Friedrich Schiller University Jena, Institute of Anatomy II (Germany); Herrmann, Rudolf [University of Augsburg, Department of Physics (Germany); Förster, Martin [Jena University Hospital – Friedrich Schiller University Jena, Department of Internal Medicine I, Division of Pulmonary Medicine and Allergy/Immunology (Germany); Reller, Armin [University of Augsburg, Department of Physics (Germany); Hilger, Ingrid, E-mail: ingrid.hilger@med.uni-jena.de [Jena University Hospital – Friedrich Schiller University Jena, Department of Experimental Radiology, Institute of Diagnostic and Interventional Radiology (Germany)

    2015-05-15

    Although cytotoxicity and endocytosis of nanoparticles have been the subject of numerous studies, investigations regarding exocytosis as an important mechanism to reduce intracellular nanoparticle accumulation are rather rare and there is a distinct lack of knowledge. The current study investigated the behavior of human microvascular endothelial cells to exocytose cerium dioxide (CeO{sub 2}) nanoparticles (18.8 nm) by utilization of specific inhibitors [brefeldin A; nocodazole; methyl-β-cyclodextrin (MβcD)] and different analytical methods (flow cytometry, transmission electron microscopy, inductively coupled plasma mass spectrometry). Overall, it was found that endothelial cells were able to release CeO{sub 2} nanoparticles via exocytosis after the migration of nanoparticle containing endosomes toward the plasma membrane. The exocytosis process occurred mainly by fusion of vesicular membranes with plasma membrane resulting in the discharge of vesicular content to extracellular environment. Nevertheless, it seems to be likely that nanoparticles present in the cytosol could leave the cells in a direct manner. MβcD treatment led to the strongest inhibition of the nanoparticle exocytosis indicating a significant role of the plasma membrane cholesterol content in the exocytosis process. Brefeldin A (inhibitor of Golgi-to-cell-surface-transport) caused a higher inhibitory effect on exocytosis than nocodazole (inhibitor of microtubules). Thus, the transfer from distal Golgi compartments to the cell surface influenced the exocytosis process of the CeO{sub 2} nanoparticles more than the microtubule-associated transport. In conclusion, endothelial cells, which came in contact with nanoparticles, e.g., after intravenously applied nano-based drugs, can regulate their intracellular nanoparticle amount, which is necessary to avoid adverse nanoparticle effects on cells.

  9. microRNAs: key triggers of neuronal cell fate

    Directory of Open Access Journals (Sweden)

    Karla F. Meza-Sosa

    2014-06-01

    Full Text Available Development of the central nervous system requires a precisely coordinated series of events. During embryonic development, different intra- and extracellular signals stimulate neural stem cells to become neural progenitors, which eventually irreversibly exit from the cell cycle to begin the first stage of neurogenesis. However, before this event occurs, the self-renewal and proliferative capacities of neural stem cells and neural progenitors must be tightly regulated. Accordingly, the participation of various evolutionary conserved microRNAs is key in distinct CNS developmental processes of many organisms including human, mouse, chicken, frog and zebrafish. microRNAs specifically recognize and regulate the expression of target mRNAs by sequence complementarity within the mRNAs 3’ untranslated region and importantly, a single microRNA can have several target mRNAs to regulate a process; likewise, a unique mRNA can be targeted by more than one microRNA. Thus, by regulating different target genes, microRNAs let-7, microRNA-124 and microRNA-9 have been shown to promote the differentiation of neural stem cells and neural progenitors into specific neural cell types while microRNA-134, microRNA-25 and microRNA-137 have been characterized as microRNAs that induce the proliferation of neural stem cells and neural progenitors. Here we review the mechanisms of action of these two sets of microRNAs and their functional implications during the transition from neural stem cells and neural progenitors to fully differentiated neurons. The genetic and epigenetic mechanisms that regulate the expression of these microRNAs as well as the role of the recently described natural RNA circles which act as natural microRNA sponges regulating post-transcriptional microRNA expression and function during the early stages of neurogenesis is also discussed.

  10. Transcriptome analysis of mammary epithelial subpopulations identifies novel determinants of lineage commitment and cell fate

    Directory of Open Access Journals (Sweden)

    Zvelebil Marketa

    2008-12-01

    Full Text Available Abstract Background Understanding the molecular control of cell lineages and fate determination in complex tissues is key to not only understanding the developmental biology and cellular homeostasis of such tissues but also for our understanding and interpretation of the molecular pathology of diseases such as cancer. The prerequisite for such an understanding is detailed knowledge of the cell types that make up such tissues, including their comprehensive molecular characterisation. In the mammary epithelium, the bulk of the tissue is composed of three cell lineages, namely the basal/myoepithelial, luminal epithelial estrogen receptor positive and luminal epithelial estrogen receptor negative cells. However, a detailed molecular characterisation of the transcriptomic differences between these three populations has not been carried out. Results A whole transcriptome analysis of basal/myoepithelial cells, luminal estrogen receptor negative cells and luminal estrogen receptor positive cells isolated from the virgin mouse mammary epithelium identified 861, 326 and 488 genes as highly differentially expressed in the three cell types, respectively. Network analysis of the transcriptomic data identified a subpopulation of luminal estrogen receptor negative cells with a novel potential role as non-professional immune cells. Analysis of the data for potential paracrine interacting factors showed that the basal/myoepithelial cells, remarkably, expressed over twice as many ligands and cell surface receptors as the other two populations combined. A number of transcriptional regulators were also identified that were differentially expressed between the cell lineages. One of these, Sox6, was specifically expressed in luminal estrogen receptor negative cells and functional assays confirmed that it maintained mammary epithelial cells in a differentiated luminal cell lineage. Conclusion The mouse mammary epithelium is composed of three main cell types with

  11. The Life and Fate of Mesenchymal Stem Cells

    Directory of Open Access Journals (Sweden)

    Elke eEggenhofer

    2014-05-01

    Full Text Available Mesenchymal stem cells (MSC are present throughout the body and are thought to play a role in tissue regeneration and control of inflammation. MSC can be easily expanded in vitro and their potential as a therapeutic option for degenerative and inflammatory disease is therefore intensively investigated. Whilst it was initially thought that MSC would replace dysfunctional cells and migrate to sites of injury to interact with inflammatory cells, experimental evidence indicates that the majority of administered MSC get trapped in capillary networks and have a short life span. In this review we discuss current knowledge on the migratory properties of endogenous and exogenous MSC and confer on how culture induced modifications of MSC may affect these properties. Finally we will discuss how, despite their limited survival, administered MSC can bring about their therapeutic effects.

  12. BMP signaling orchestrates a transcriptional network to control the fate of mesenchymal stem cells in mice.

    Science.gov (United States)

    Feng, Jifan; Jing, Junjun; Li, Jingyuan; Zhao, Hu; Punj, Vasu; Zhang, Tingwei; Xu, Jian; Chai, Yang

    2017-07-15

    Signaling pathways are used reiteratively in different developmental processes yet produce distinct cell fates through specific downstream transcription factors. In this study, we used tooth root development as a model with which to investigate how the BMP signaling pathway regulates transcriptional complexes to direct the fate determination of multipotent mesenchymal stem cells (MSCs). We first identified the MSC population supporting mouse molar root growth as Gli1+ cells. Using a Gli1-driven Cre-mediated recombination system, our results provide the first in vivo evidence that BMP signaling activity is required for the odontogenic differentiation of MSCs. Specifically, we identified the transcription factors Pax9, Klf4, Satb2 and Lhx8 as being downstream of BMP signaling and expressed in a spatially restricted pattern that is potentially involved in determining distinct cellular identities within the dental mesenchyme. Finally, we found that overactivation of one key transcription factor, Klf4, which is associated with the odontogenic region, promotes odontogenic differentiation of MSCs. Collectively, our results demonstrate the functional significance of BMP signaling in regulating MSC fate during root development and shed light on how BMP signaling can achieve functional specificity in regulating diverse organ development. © 2017. Published by The Company of Biologists Ltd.

  13. Endoplasmic Reticulum Stress, Unfolded Protein Response, and Cancer Cell Fate

    Science.gov (United States)

    Corazzari, Marco; Gagliardi, Mara; Fimia, Gian Maria; Piacentini, Mauro

    2017-01-01

    Perturbation of endoplasmic reticulum (ER) homeostasis results in a stress condition termed “ER stress” determining the activation of a finely regulated program defined as unfolded protein response (UPR) and whose primary aim is to restore this organelle’s physiological activity. Several physiological and pathological stimuli deregulate normal ER activity causing UPR activation, such as hypoxia, glucose shortage, genome instability, and cytotoxic compounds administration. Some of these stimuli are frequently observed during uncontrolled proliferation of transformed cells, resulting in tumor core formation and stage progression. Therefore, it is not surprising that ER stress is usually induced during solid tumor development and stage progression, becoming an hallmark of such malignancies. Several UPR components are in fact deregulated in different tumor types, and accumulating data indicate their active involvement in tumor development/progression. However, although the UPR program is primarily a pro-survival process, sustained and/or prolonged stress may result in cell death induction. Therefore, understanding the mechanism(s) regulating the cell survival/death decision under ER stress condition may be crucial in order to specifically target tumor cells and possibly circumvent or overcome tumor resistance to therapies. In this review, we discuss the role played by the UPR program in tumor initiation, progression and resistance to therapy, highlighting the recent advances that have improved our understanding of the molecular mechanisms that regulate the survival/death switch. PMID:28491820

  14. Endoplasmic Reticulum Stress, Unfolded Protein Response, and Cancer Cell Fate

    Directory of Open Access Journals (Sweden)

    Marco Corazzari

    2017-04-01

    Full Text Available Perturbation of endoplasmic reticulum (ER homeostasis results in a stress condition termed “ER stress” determining the activation of a finely regulated program defined as unfolded protein response (UPR and whose primary aim is to restore this organelle’s physiological activity. Several physiological and pathological stimuli deregulate normal ER activity causing UPR activation, such as hypoxia, glucose shortage, genome instability, and cytotoxic compounds administration. Some of these stimuli are frequently observed during uncontrolled proliferation of transformed cells, resulting in tumor core formation and stage progression. Therefore, it is not surprising that ER stress is usually induced during solid tumor development and stage progression, becoming an hallmark of such malignancies. Several UPR components are in fact deregulated in different tumor types, and accumulating data indicate their active involvement in tumor development/progression. However, although the UPR program is primarily a pro-survival process, sustained and/or prolonged stress may result in cell death induction. Therefore, understanding the mechanism(s regulating the cell survival/death decision under ER stress condition may be crucial in order to specifically target tumor cells and possibly circumvent or overcome tumor resistance to therapies. In this review, we discuss the role played by the UPR program in tumor initiation, progression and resistance to therapy, highlighting the recent advances that have improved our understanding of the molecular mechanisms that regulate the survival/death switch.

  15. Microspore embryogenesis: reprogramming cell fate from pollen to embryo development

    NARCIS (Netherlands)

    Hui Li,

    2014-01-01

    Microspore embryogenesis is an expression of plant cell totipotency that leads to the production of haploid embryos. Besides being a widely exploited plant breeding tool, microspore embryogenesis is also a fascinating system that can be used to obtain a deeper mechanistic understanding of plant

  16. A subset of osteoblasts expressing high endogenous levels of PPARgamma switches fate to adipocytes in the rat calvaria cell culture model.

    Directory of Open Access Journals (Sweden)

    Yuji Yoshiko

    2010-07-01

    Full Text Available Understanding fate choice and fate switching between the osteoblast lineage (ObL and adipocyte lineage (AdL is important to understand both the developmental inter-relationships between osteoblasts and adipocytes and the impact of changes in fate allocation between the two lineages in normal aging and certain diseases. The goal of this study was to determine when during lineage progression ObL cells are susceptible to an AdL fate switch by activation of endogenous peroxisome proliferator-activated receptor (PPARgamma.Multiple rat calvaria cells within the ObL developmental hierarchy were isolated by either fractionation on the basis of expression of alkaline phosphatase or retrospective identification of single cell-derived colonies, and treated with BRL-49653 (BRL, a synthetic ligand for PPARgamma. About 30% of the total single cell-derived colonies expressed adipogenic potential (defined cytochemically when BRL was present. Profiling of ObL and AdL markers by qRT-PCR on amplified cRNA from over 160 colonies revealed that BRL-dependent adipogenic potential correlated with endogenous PPARgamma mRNA levels. Unexpectedly, a significant subset of relatively mature ObL cells exhibited osteo-adipogenic bipotentiality. Western blotting and immunocytochemistry confirmed that ObL cells co-expressed multiple mesenchymal lineage determinants (runt-related transcription factor 2 (Runx2, PPARgamma, Sox9 and MyoD which localized in the cytoplasm initially, and only Runx2 translocated to the nucleus during ObL progression. Notably, however, some cells exhibited both PPARgamma and Runx2 nuclear labeling with concomitant upregulation of expression of their target genes with BRL treatment.We conclude that not only immature but a subset of relatively mature ObL cells characterized by relatively high levels of endogenous PPARgamma expression can be switched to the AdL. The fact that some ObL cells maintain capacity for adipogenic fate selection even at relatively

  17. Numb and Numbl act to determine mammary myoepithelial cell fate, maintain epithelial identity, and support lactogenesis.

    Science.gov (United States)

    Zhang, Yue; Li, Fengyin; Song, Yongli; Sheng, Xiaole; Ren, Fazheng; Xiong, Kai; Chen, Lei; Zhang, Hongquan; Liu, Dequan; Lengner, Christopher J; Xue, Lixiang; Yu, Zhengquan

    2016-10-01

    Mammary epithelium is comprised of an inner layer of luminal epithelial cells and an outer layer of contractile myoepithelial cells with mesenchymal properties. These two compartments interact throughout mammary morphogenesis to form branching ducts during puberty and terminate in secretory alveoli during lactation. It is not known how the myoepithelial cell lineage is specified, nor how signals in myoepithelial cells contribute to lactogenesis. Here, we show that Numb and Numbl are enriched in mammary myoepithelial cells, with their expression peaking during pregnancy. We use conditional Numb- and Numbl-knockout mouse models to demonstrate that loss of Numb/Numbl compromised the myoepithelial layer and expanded the luminal layer, led epithelial cells to undergo epithelial-to-mesenchymal transition, and resulted in lactation failure as a result of abnormal alveolar formation during pregnancy. Numb and Numbl function via repression of the Notch signaling pathway and of the p53-p21 axis during mammary gland development. These findings highlight the importance of Numb and Numbl in the control of myoepithelial cell fate determination, epithelial identity, and lactogenesis.-Zhang Y., Li, F., Song, Y., Sheng, X., Ren, F., Xiong, K., Chen, L., Zhang, H., Liu, D., Lengner, C. J., Xue, L., Yu, Z. Numb and Numbl act to determine mammary myoepithelial cell fate, maintain epithelial identity, and support lactogenesis. © FASEB.

  18. Emerging Importance of Phytochemicals in Regulation of Stem Cells Fate via Signaling Pathways.

    Science.gov (United States)

    Dadashpour, Mehdi; Pilehvar-Soltanahmadi, Younes; Zarghami, Nosratollah; Firouzi-Amandi, Akram; Pourhassan-Moghaddam, Mohammad; Nouri, Mohammad

    2017-11-01

    To reach ideal therapeutic potential of stem cells for regenerative medicine purposes, it is essential to retain their self-renewal and differentiation capacities. Currently, biological factors are extensively used for stemness maintaining and differentiation induction of stem cells. However, low stability, high cost, complicated production process, and risks associated with viral/endotoxin infection hamper the widespread use of biological factors in the stem cell biology. Moreover, regarding the modulation of several signaling cascades, which lead to a distinct fate, phytochemicals are preferable in the stem cells biology because of their efficiency. Considering the issues related to the application of biological factors and potential advantages of phytochemicals in stem cell engineering, there is a considerable increasing trend in studies associated with the application of novel alternative molecules in the stem cell biology. In support of this statement, we aimed to highlight the various effects of phytochemicals on signaling cascades involved in commitment of stem cells. Hence, in this review, the current trends in the phytochemicals-based modulation of stem cell fate have been addressed. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  19. MSX2 in ameloblast cell fate and activity

    OpenAIRE

    Babajko, Sylvie; De la Dure-Molla, Muriel; Jedeon, Katia; Berdal, Ariane

    2015-01-01

    International audience; While many effectors have been identified in enamel matrix and cells via genetic studies, physiological networks underlying their expression levels and thus the natural spectrum of enamel thickness and degree of mineralization are now just emerging. Several transcription factors are candidates for enamel gene expression regulation and thus the control of enamel quality. Some of these factors, such as MSX2, are mainly confined to the dental epithelium. MSX2 homeoprotein...

  20. Cell Type-specific Alternative Splicing Governs Cell Fate in the Developing Cerebral Cortex

    Science.gov (United States)

    Zhang, Xiaochang; Chen, Ming Hui; Wu, Xuebing; Kodani, Andrew; Fan, Jean; Doan, Ryan; Ozawa, Manabu; Ma, Jacqueline; Yoshida, Nobuaki; Reiter, Jeremy F.; Black, Douglas L.; Kharchenko, Peter V.; Sharp, Phillip A.; Walsh, Christopher A.

    2017-01-01

    SUMMARY Alternative splicing is prevalent in the mammalian brain. To interrogate the functional role of alternative splicing in neural development, we analyzed purified neural progenitor cells (NPCs) and neurons from developing cerebral cortices, revealing hundreds of differentially spliced exons that preferentially alter key protein domains—especially in cytoskeletal proteins—and can harbor disease-causing mutations. We show that Ptbp1 and Rbfox proteins antagonistically govern the NPC-to-neuron transition by regulating neuron-specific exons. While Ptbp1 maintains apical progenitors partly through suppressing a poison exon of Flna in NPCs, Rbfox proteins promote neuronal differentiation by switching Ninein from a centrosomal splice form in NPCs to a non-centrosomal isoform in neurons. We further uncover an intronic human mutation within a PTBP1 binding site that disrupts normal skipping of the FLNA poison exon in NPCs and causes a brain-specific malformation. Our study indicates that dynamic control of alternative splicing governs cell fate in cerebral cortical development. PMID:27565344

  1. Cell-Type-Specific Alternative Splicing Governs Cell Fate in the Developing Cerebral Cortex.

    Science.gov (United States)

    Zhang, Xiaochang; Chen, Ming Hui; Wu, Xuebing; Kodani, Andrew; Fan, Jean; Doan, Ryan; Ozawa, Manabu; Ma, Jacqueline; Yoshida, Nobuaki; Reiter, Jeremy F; Black, Douglas L; Kharchenko, Peter V; Sharp, Phillip A; Walsh, Christopher A

    2016-08-25

    Alternative splicing is prevalent in the mammalian brain. To interrogate the functional role of alternative splicing in neural development, we analyzed purified neural progenitor cells (NPCs) and neurons from developing cerebral cortices, revealing hundreds of differentially spliced exons that preferentially alter key protein domains-especially in cytoskeletal proteins-and can harbor disease-causing mutations. We show that Ptbp1 and Rbfox proteins antagonistically govern the NPC-to-neuron transition by regulating neuron-specific exons. Whereas Ptbp1 maintains apical progenitors partly through suppressing a poison exon of Flna in NPCs, Rbfox proteins promote neuronal differentiation by switching Ninein from a centrosomal splice form in NPCs to a non-centrosomal isoform in neurons. We further uncover an intronic human mutation within a PTBP1-binding site that disrupts normal skipping of the FLNA poison exon in NPCs and causes a brain-specific malformation. Our study indicates that dynamic control of alternative splicing governs cell fate in cerebral cortical development. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Integrative modelling of the influence of MAPK network on cancer cell fate decision.

    Directory of Open Access Journals (Sweden)

    Luca Grieco

    2013-10-01

    Full Text Available The Mitogen-Activated Protein Kinase (MAPK network consists of tightly interconnected signalling pathways involved in diverse cellular processes, such as cell cycle, survival, apoptosis and differentiation. Although several studies reported the involvement of these signalling cascades in cancer deregulations, the precise mechanisms underlying their influence on the balance between cell proliferation and cell death (cell fate decision in pathological circumstances remain elusive. Based on an extensive analysis of published data, we have built a comprehensive and generic reaction map for the MAPK signalling network, using CellDesigner software. In order to explore the MAPK responses to different stimuli and better understand their contributions to cell fate decision, we have considered the most crucial components and interactions and encoded them into a logical model, using the software GINsim. Our logical model analysis particularly focuses on urinary bladder cancer, where MAPK network deregulations have often been associated with specific phenotypes. To cope with the combinatorial explosion of the number of states, we have applied novel algorithms for model reduction and for the compression of state transition graphs, both implemented into the software GINsim. The results of systematic simulations for different signal combinations and network perturbations were found globally coherent with published data. In silico experiments further enabled us to delineate the roles of specific components, cross-talks and regulatory feedbacks in cell fate decision. Finally, tentative proliferative or anti-proliferative mechanisms can be connected with established bladder cancer deregulations, namely Epidermal Growth Factor Receptor (EGFR over-expression and Fibroblast Growth Factor Receptor 3 (FGFR3 activating mutations.

  3. Viscoelastic properties of differentiating blood cells are fate- and function-dependent.

    Directory of Open Access Journals (Sweden)

    Andrew E Ekpenyong

    Full Text Available Although cellular mechanical properties are known to alter during stem cell differentiation, understanding of the functional relevance of such alterations is incomplete. Here, we show that during the course of differentiation of human myeloid precursor cells into three different lineages, the cells alter their viscoelastic properties, measured using an optical stretcher, to suit their ultimate fate and function. Myeloid cells circulating in blood have to be advected through constrictions in blood vessels, engendering the need for compliance at short time-scales (minutes, compared to undifferentiated cells. These findings suggest that reduction in steady-state viscosity is a physiological adaptation for enhanced migration through tissues. Our results indicate that the material properties of cells define their function, can be used as a cell differentiation marker and could serve as target for novel therapies.

  4. Fate study of water-borne gram positive vegetative bacterial cells with Raman microscopy

    Science.gov (United States)

    Guicheteau, Jason; Tripathi, Ashish; Minter, Jennifer; Wilcox, Phillip; Christesen, Steven

    2010-04-01

    We present an initial bacterial fate study of Gram positive vegetative cells suspended in water and stored at ambient room temperature via Raman spectroscopy monitoring. Two types of cells were considered for this study: vegetative cells of Bacillus cereus, Bacillus thuringiensis which contain the polyhydroxybutyric acid (PHBA) as an energy storage compound and Bacillus subtlilis cells which do not. The cells were cultured specifically for this project. Immediately following the culturing phase, the bacteria were extracted, cleaned and at the onset of the study were suspended in de-ionized water and stored at room temperature. Aliquots of suspensions were deposited onto aluminum slides at different times and allowed to dry for Raman analysis. Spectra from multiple regions of each dried spot and each deposit time were acquired along with the bright-field and fluorescence images. Results were examined to investigate the effect of suspension time on the spectral signatures as well as the fate behavior of the three types of cells investigated. The cells were monitored daily for over a 14 period during which time the onset of starvation induced sporulation was observed.

  5. Fate of mucilage cell wall polysaccharides during coffee fermentation.

    Science.gov (United States)

    Avallone, S; Guiraud, J P; Guyot, B; Olguin, E; Brillouet, J M

    2001-11-01

    Effects of a 20-h fermentation on cell wall polysaccharides from the mucilage of pulped coffee beans were examined and compared to those of unfermented beans, on alcohol insoluble residues (AIRs), their hot-water-soluble crude pectic substances (PECTs), and their hot-water-insoluble residues (RESs). Yields and compositions were very similar: AIRs, which consisted of approximately 30% highly methylated pectic substances, approximately 9% cellulose, and approximately 15% neutral noncellulosic polysaccharides, exhibited no apparent degradation. However, PECTs from fermented beans were shown to have undergone a slight reduction of their intrinsic viscosity and weight-average molecular weight by capillary viscosimetry and high-performance size-exclusion chromatography. After fermentation, hot-water-insoluble pectic substances of RES exhibited partial de-esterification. Removal of coffee bean mucilage by natural fermentation seems to result from a restricted pectolysis, the mechanism of which remains to be elucidated.

  6. Lineage, Fate, and Fate Potential of NG2-glia

    Science.gov (United States)

    Nishiyama, Akiko; Boshans, Linda; Goncalves, Christopher M.; Wegrzyn, Jill; Patel, Kiran D.

    2015-01-01

    NG2 cells represent a fourth major glial cell population in the mammalian central nervous system (CNS). They arise from discrete germinal zones in mid-gestation embryos and expand to occupy the entire CNS parenchyma. Genetic fate mapping studies have shown that oligodendrocytes and a subpopulation of ventral protoplasmic astrocytes arise from NG2 cells. This review describes recent findings on the fate and fate potential of NG2 cells under physiological and pathological conditions. We discuss age-dependent changes in the fate and fate potential of NG2 cells and possible mechanisms that could be involved in restricting their oligodendrocyte differentiation or fate plasticity. PMID:26301825

  7. Using cell fate attractors to uncover transcriptional regulation of HL60 neutrophil differentiation

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    Kauffman Stuart A

    2009-02-01

    Full Text Available Abstract Background The process of cellular differentiation is governed by complex dynamical biomolecular networks consisting of a multitude of genes and their products acting in concert to determine a particular cell fate. Thus, a systems level view is necessary for understanding how a cell coordinates this process and for developing effective therapeutic strategies to treat diseases, such as cancer, in which differentiation plays a significant role. Theoretical considerations and recent experimental evidence support the view that cell fates are high dimensional attractor states of the underlying molecular networks. The temporal behavior of the network states progressing toward different cell fate attractors has the potential to elucidate the underlying molecular mechanisms governing differentiation. Results Using the HL60 multipotent promyelocytic leukemia cell line, we performed experiments that ultimately led to two different cell fate attractors by two treatments of varying dosage and duration of the differentiation agent all-trans-retinoic acid (ATRA. The dosage and duration combinations of the two treatments were chosen by means of flow cytometric measurements of CD11b, a well-known early differentiation marker, such that they generated two intermediate populations that were poised at the apparently same stage of differentiation. However, the population of one treatment proceeded toward the terminally differentiated neutrophil attractor while that of the other treatment reverted back toward the undifferentiated promyelocytic attractor. We monitored the gene expression changes in the two populations after their respective treatments over a period of five days and identified a set of genes that diverged in their expression, a subset of which promotes neutrophil differentiation while the other represses cell cycle progression. By employing promoter based transcription factor binding site analysis, we found enrichment in the set of divergent

  8. Cancer becomes wasteful: emerging roles of exosomes in cell-fate determination

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    Franz Wendler

    2013-09-01

    Full Text Available Extracellular vesicles (EVs, including exosomes, have been widely recognized for their role in intercellular communication of the immune response system. In the past few years, significance has been given to exosomes in the induction and modulation of cell-fate-inducing signalling pathways, such as the Hedgehog (Hh, Wnts, Notch, transforming growth factor (TGF-β, epidermal growth factor (EGF and fibroblast growth factor (FGF pathways, placing them in the wider context of development and also of cancer. These protein families induce signalling cascades responsible for tissue specification, homeostasis and maintenance. Exosomes contribute to cell-fate signal secretion, and vice versa exosome secretion can be induced by these proteins. Interestingly, exosomes can also transfer their mRNA to host cells or modulate the signalling pathways directly by the removal of downstream effector molecules from the cell. Surprisingly, much of what we know about the function of exosomes in cell determination is gathered from pathological transformed cancer cells and wound healing while data about their biogenesis and biology in normal developing and adult tissue lag behind. In this report, we will summarize some of the published literature and point to current advances and questions in this fast-developing topic. In a brief foray, we will also update and shortly discuss their potential in diagnosis and targeted cancer treatment.

  9. Regulation of myeloid leukemia by the cell fate determinant Musashi

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    Ito, Takahiro; Kwon, Hyog Young; Zimdahl, Bryan; Congdon, Kendra L.; Blum, Jordan; Lento, William E.; Zhao, Chen; Lagoo, Anand; Gerrard, Gareth; Foroni, Letizia; Goldman, John; Goh, Harriet; Kim, Soo-Hyun; Kim, Dong-Wook; Chuah, Charles; Oehler, Vivian G.; Radich, Jerald P.; Jordan, Craig T.; Reya, Tannishtha

    2010-01-01

    Chronic myelogenous leukemia (CML) can progress from an indolent chronic phase to an aggressive blast crisis phase1 but the molecular basis of this transition remains poorly understood. Here we have used mouse models of CML2,3 to show that disease progression is regulated by the Musashi-Numb signaling axis4,5. Specifically, we find that chronic phase is marked by high and blast crisis phase by low levels of Numb expression, and that ectopic expression of Numb promotes differentiation and impairs advanced phase disease in vivo. As a possible explanation for the decreased levels of Numb in blast crisis, we show that NUP98-HOXA9, an oncogene associated with blast crisis CML6,7, can trigger expression of the RNA binding protein Musashi2 (Msi2) which in turn represses Numb. Importantly, loss of Msi2 restores Numb expression and significantly impairs the development and propagation of blast crisis CML in vitro and in vivo. Finally, we show that Msi2 expression is not only highly upregulated during human CML progression but is also an early indicator of poorer prognosis. These data show that the Musashi-Numb pathway can control the differentiation of CML cells, and raise the possibility that targeting this pathway may provide a new strategy for therapy of aggressive leukemias. PMID:20639863

  10. The binding, transport and fate of aluminium in biological cells.

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    Exley, Christopher; Mold, Matthew J

    2015-04-01

    Aluminium is the most abundant metal in the Earth's crust and yet, paradoxically, it has no known biological function. Aluminium is biochemically reactive, it is simply that it is not required for any essential process in extant biota. There is evidence neither of element-specific nor evolutionarily conserved aluminium biochemistry. This means that there are no ligands or chaperones which are specific to its transport, there are no transporters or channels to selectively facilitate its passage across membranes, there are no intracellular storage proteins to aid its cellular homeostasis and there are no pathways which evolved to enable the metabolism and excretion of aluminium. Of course, aluminium is found in every compartment of every cell of every organism, from virus through to Man. Herein we have investigated each of the 'silent' pathways and metabolic events which together constitute a form of aluminium homeostasis in biota, identifying and evaluating as far as is possible what is known and, equally importantly, what is unknown about its uptake, transport, storage and excretion. Copyright © 2014 Elsevier GmbH. All rights reserved.

  11. [Genetic transformation and fate of heterological DNA in bacterial cells].

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    Piechowska, Mirosława

    2015-01-01

    Secretion of a metabolite enabling Streptococci to undergo genetic transformation was discovered. The metabolite combined with an optimization process were applied to increase the transformation yield about 20-fold. It was observed that large amounts of DNA exert a bactericidal effect, indicating the ability of at least 70% of cells to uptake the polymer. While studying the molecular mechanism of transformation of Bacillus subtilis it was shown that the uptaken DNA forms complexes with bacterial proteins, which hinders determination of its structure. A method was found to dissociate these complexes which enabled to determine the single-stranded structure of the uptaken DNA. Donor DNA fragments incorporated into the host DNA were of about 10 Da. Non-transforming DNA can be uptaken similarly but does not undergo incorporation into the host DNA. The selectivity of Bacillus subtilis receptors was determined towards DNA of phages containing modified bases: uracil, putrescinyl-thymine and its acetylated derivative, 5'-hydroxymethylcytosine and its glycosylated derivative and also towards double-stranded RNA of f2 phage. All these modifications were tolerated by the cellular receptors, with the exception of glycosylation and the 2'-OH group in RNA.

  12. Suppression of the SOX2 Neural Effector Gene by PRDM1 Promotes Human Germ Cell Fate in Embryonic Stem Cells

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    I-Ying Lin

    2014-02-01

    Full Text Available The mechanisms of transcriptional regulation underlying human primordial germ cell (PGC differentiation are largely unknown. The transcriptional repressor Prdm1/Blimp-1 is known to play a critical role in controlling germ cell specification in mice. Here, we show that PRDM1 is expressed in developing human gonads and contributes to the determination of germline versus neural fate in early development. We show that knockdown of PRDM1 in human embryonic stem cells (hESCs impairs germline potential and upregulates neural genes. Conversely, ectopic expression of PRDM1 in hESCs promotes the generation of cells that exhibit phenotypic and transcriptomic features of early PGCs. Furthermore, PRDM1 suppresses transcription of SOX2. Overexpression of SOX2 in hESCs under conditions favoring germline differentiation skews cell fate from the germline to the neural lineage. Collectively, our results demonstrate that PRDM1 serves as a molecular switch to modulate the divergence of neural or germline fates through repression of SOX2 during human development.

  13. Gastrin: a distinct fate of neurogenin3 positive progenitor cells in the embryonic pancreas.

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    Yaron Suissa

    Full Text Available Neurogenin3(+ (Ngn3(+ progenitor cells in the developing pancreas give rise to five endocrine cell types secreting insulin, glucagon, somatostatin, pancreatic polypeptide and ghrelin. Gastrin is a hormone produced primarily by G-cells in the stomach, where it functions to stimulate acid secretion by gastric parietal cells. Gastrin is expressed in the embryonic pancreas and is common in islet cell tumors, but the lineage and regulators of pancreatic gastrin(+ cells are not known. We report that gastrin is abundantly expressed in the embryonic pancreas and disappears soon after birth. Some gastrin(+ cells in the developing pancreas co-express glucagon, ghrelin or pancreatic polypeptide, but many gastrin(+ cells do not express any other islet hormone. Pancreatic gastrin(+ cells express the transcription factors Nkx6.1, Nkx2.2 and low levels of Pdx1, and derive from Ngn3(+ endocrine progenitor cells as shown by genetic lineage tracing. Using mice deficient for key transcription factors we show that gastrin expression depends on Ngn3, Nkx2.2, NeuroD1 and Arx, but not Pax4 or Pax6. Finally, gastrin expression is induced upon differentiation of human embryonic stem cells to pancreatic endocrine cells expressing insulin. Thus, gastrin(+ cells are a distinct endocrine cell type in the pancreas and an alternative fate of Ngn3+ cells.

  14. Gastrin: a distinct fate of neurogenin3 positive progenitor cells in the embryonic pancreas.

    Science.gov (United States)

    Suissa, Yaron; Magenheim, Judith; Stolovich-Rain, Miri; Hija, Ayat; Collombat, Patrick; Mansouri, Ahmed; Sussel, Lori; Sosa-Pineda, Beatriz; McCracken, Kyle; Wells, James M; Heller, R Scott; Dor, Yuval; Glaser, Benjamin

    2013-01-01

    Neurogenin3(+) (Ngn3(+)) progenitor cells in the developing pancreas give rise to five endocrine cell types secreting insulin, glucagon, somatostatin, pancreatic polypeptide and ghrelin. Gastrin is a hormone produced primarily by G-cells in the stomach, where it functions to stimulate acid secretion by gastric parietal cells. Gastrin is expressed in the embryonic pancreas and is common in islet cell tumors, but the lineage and regulators of pancreatic gastrin(+) cells are not known. We report that gastrin is abundantly expressed in the embryonic pancreas and disappears soon after birth. Some gastrin(+) cells in the developing pancreas co-express glucagon, ghrelin or pancreatic polypeptide, but many gastrin(+) cells do not express any other islet hormone. Pancreatic gastrin(+) cells express the transcription factors Nkx6.1, Nkx2.2 and low levels of Pdx1, and derive from Ngn3(+) endocrine progenitor cells as shown by genetic lineage tracing. Using mice deficient for key transcription factors we show that gastrin expression depends on Ngn3, Nkx2.2, NeuroD1 and Arx, but not Pax4 or Pax6. Finally, gastrin expression is induced upon differentiation of human embryonic stem cells to pancreatic endocrine cells expressing insulin. Thus, gastrin(+) cells are a distinct endocrine cell type in the pancreas and an alternative fate of Ngn3+ cells.

  15. Evidence that metabolism and chromosome copy number control mutually exclusive cell fates in Bacillus subtilis

    Science.gov (United States)

    Chai, Yunrong; Norman, Thomas; Kolter, Roberto; Losick, Richard

    2011-01-01

    Bacillus subtilis chooses between matrix production and spore formation, which are both controlled by the regulator Spo0A∼P. We report that metabolism and chromosome copy number dictate which fate is adopted. Conditions that favour low Spo0A∼P levels promote matrix production, whereas conditions favouring high levels trigger sporulation. Spo0A∼P directs the synthesis of SinI, an antirepressor for the SinR repressor of matrix genes. The regulatory region of sinI contains an activator site that Spo0A∼P binds strongly and operators that bind Spo0A∼P weakly. Evidence shows that low Spo0A∼P levels turn sinI ON and high levels turn sinI OFF and instead switch sporulation ON. Cells in which sinI and sinR were transplanted from their normal position near the chromosome replication terminus to positions near the origin and cells that harboured an extra copy of the genes were blocked in matrix production. Thus, matrix gene expression is sensitive to the number of copies of sinI and sinR. Because cells at the start of sporulation have two chromosomes and matrix-producing cells one, chromosome copy number could contribute to cell-fate determination. PMID:21326214

  16. Reactive Oxygen Species and Mitochondrial Homeostasis as Regulators of Stem Cell Fate and Function.

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    Tan, Darren Q; Suda, Toshio

    2017-10-26

    The precise role and impact of reactive oxygen species (ROS) in stem cells, which are essential for lifelong tissue homeostasis and regeneration, remain of significant interest to the field. The long-term regenerative potential of a stem cell compartment is determined by the delicate balance between quiescence, self-renewal, and differentiation, all of which can be influenced by ROS levels. Recent Advances: The past decade has seen a growing appreciation for the importance of ROS and redox homeostasis in various stem cell compartments, particularly those of hematopoietic, neural, and muscle tissues. In recent years, the importance of proteostasis and mitochondria in relation to stem cell biology and redox homeostasis has garnered considerable interest. Here, we explore the reciprocal relationship between ROS and stem cells, with significant emphasis on mitochondria as a core component of redox homeostasis. We discuss how redox signaling, involving cell-fate determining protein kinases and transcription factors, can control stem cell function and fate. We also address the impact of oxidative stress on stem cells, especially oxidative damage of lipids, proteins, and nucleic acids. We further discuss ROS management in stem cells, and present recent evidence supporting the importance of mitochondrial activity and its modulation (via mitochondrial clearance, biogenesis, dynamics, and distribution [i.e., segregation and transfer]) in stem cell redox homeostasis. Therefore, elucidating the intricate links between mitochondria, cellular metabolism, and redox homeostasis is envisioned to be critical for our understanding of ROS in stem cell biology and its therapeutic relevance in regenerative medicine. Antioxid. Redox Signal. 00, 000-000.

  17. The Effect of Mesenchymal Stem Cell-Derived Extracellular Vesicles on Hematopoietic Stem Cells Fate

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    Hamze Timari

    2017-12-01

    Full Text Available Hematopoietic stem cells (HSCs are multipotent stem cells, with self-renewal ability as well as ability to generate all blood cells. Mesenchymal stem cells (MSCs are multipotent stem cells, with self-renewal ability, and capable of differentiating into a variety of cell types. MSCs have supporting effects on hematopoiesis; through direct intercellular communications as well as secreting cytokines, chemokines, and extracellular vesicles (EVs. Recent investigations demonstrated that some biological functions and effects of MSCs are mediated by their EVs. MSC-EVs are the cell membrane and endosomal membrane compartments, which are important mediators in the intercellular communications. MSC-EVs contain some of the molecules such as proteins, mRNA, siRNA, and miRNA from their parental cells. MSC-EVs are able to inhibit tumor, repair damaged tissue, and modulate immune system responses. MSC-EVs compared to their parental cells, may have the specific safety advantages such as the lower potential to trigger immune system responses and limited side effects. Recently some studies demonstrated the effect of MSC-EVs on the expansion, differentiation, and clinical applications of HSCs such as improvement of hematopoietic stem cell transplantation (HSCT and inhibition of graft versus host disease (GVHD. HSCT may be the only therapeutic choice for patients who suffer from malignant and non-malignant hematological disorders. However, there are several severe side effects such GVHD that restricts the successfulness of HSCT. In this review, we will discuss the most important effects of MSCs and MSC-EVs on the improvement of HSCT, inhibition and treatment of GVHD, as well as, on the expansion of HSCs.

  18. Emergence of Form from Function - Mechanical Engineering Approaches to Probe the Role of Stem Cell Mechanoadaptation in Sealing Cell Fate.

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    Knothe Tate, Melissa L; Gunning, Peter W; Sansalone, Vittorio

    2016-10-14

    Stem cell "mechanomics" refers to the effect of mechanical cues on stem cell and matrix biology, where cell shape and fate are intrinsic manifestations of form and function. Before specialization, the stem cell itself serves as a sensor and actuator; its structure emerges from its local mechanical milieu as the cell adapts over time. Coupling of novel spatiotemporal imaging and computational methods allows for linking of the energy of adaptation to the structure, biology and mechanical function of the cell. Cutting edge imaging methods enable probing of mechanisms by which stem cells' emergent anisotropic architecture and fate commitment occurs. A novel cell-scale model provides a mechanistic framework to describe stem cell growth and remodeling through mechanical feedback; making use of a generalized virtual power principle, the model accounts for the rate of doing work or the rate of using energy to effect the work. This coupled approach provides a basis to elucidate mechanisms underlying the stem cell's innate capacity to adapt to mechanical stimuli as well as the role of mechanoadaptation in lineage commitment. An understanding of stem cell mechanoadaptation is key to deciphering lineage commitment, during prenatal development, postnatal wound healing, and engineering of tissues.

  19. Putting things in place for fertilization: discovering roles for importin proteins in cell fate and spermatogenesis

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    Kate L. Loveland

    2015-01-01

    Full Text Available Importin proteins were originally characterized for their central role in protein transport through the nuclear pores, the only intracellular entry to the nucleus. This vital function must be tightly regulated to control access by transcription factors and other nuclear proteins to genomic DNA, to achieve appropriate modulation of cellular behaviors affecting cell fate. Importin-mediated nucleocytoplasmic transport relies on their specific recognition of cargoes, with each importin binding to distinct and overlapping protein subsets. Knowledge of importin function has expanded substantially in regard to three key developmental systems: embryonic stem cells, muscle cells and the germ line. In the decade since the potential for regulated nucleocytoplasmic transport to contribute to spermatogenesis was proposed, we and others have shown that the importins that ferry transcription factors into the nucleus perform additional roles, which control cell fate. This review presents key findings from studies of mammalian spermatogenesis that reveal potential new pathways by which male fertility and infertility arise. These studies of germline genesis illuminate new ways in which importin proteins govern cellular differentiation, including via directing proteins to distinct intracellular compartments and by determining cellular stress responses.

  20. miR-27b controls venous specification and tip cell fate.

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    Biyashev, Dauren; Veliceasa, Dorina; Topczewski, Jacek; Topczewska, Jolanta M; Mizgirev, Igor; Vinokour, Elena; Reddi, Alagarsamy L; Licht, Jonathan D; Revskoy, Sergei Y; Volpert, Olga V

    2012-03-15

    We discovered that miR-27b controls 2 critical vascular functions: it turns the angiogenic switch on by promoting endothelial tip cell fate and sprouting and it promotes venous differentiation. We have identified its targets, a Notch ligand Delta-like ligand 4 (Dll4) and Sprouty homologue 2 (Spry2). miR-27b knockdown in zebrafish and mouse tissues severely impaired vessel sprouting and filopodia formation. Moreover, miR-27b was necessary for the formation of the first embryonic vein in fish and controlled the expression of arterial and venous markers in human endothelium, including Ephrin B2 (EphB2), EphB4, FMS-related tyrosine kinase 1 (Flt1), and Flt4. In zebrafish, Dll4 inhibition caused increased sprouting and longer intersegmental vessels and exacerbated tip cell migration. Blocking Spry2 caused premature vessel branching. In contrast, Spry2 overexpression eliminated the tip cell branching in the intersegmental vessels. Blockade of Dll4 and Spry2 disrupted arterial specification and augmented the expression of venous markers. Blocking either Spry2 or Dll4 rescued the miR-27b knockdown phenotype in zebrafish and in mouse vascular explants, pointing to essential roles of these targets downstream of miR-27b. Our study identifies critical role of miR-27b in the control of endothelial tip cell fate, branching, and venous specification and determines Spry2 and Dll4 as its essential targets.

  1. Early perturbation in mitochondria redox homeostasis in response to environmental stress predicts cell fate in diatoms

    Science.gov (United States)

    van Creveld, Shiri Graff; Rosenwasser, Shilo; Schatz, Daniella; Koren, Ilan; Vardi, Assaf

    2015-01-01

    Diatoms are ubiquitous marine photosynthetic eukaryotes that are responsible for about 20% of global photosynthesis. Nevertheless, little is known about the redox-based mechanisms that mediate diatom sensing and acclimation to environmental stress. Here we used a redox-sensitive green fluorescent protein sensor targeted to various subcellular organelles in the marine diatom Phaeodactylum tricornutum, to map the spatial and temporal oxidation patterns in response to environmental stresses. Specific organelle oxidation patterns were found in response to various stress conditions such as oxidative stress, nutrient limitation and exposure to diatom-derived infochemicals. We found a strong correlation between the mitochondrial glutathione (GSH) redox potential (EGSH) and subsequent induction of cell death in response to the diatom-derived unsaturated aldehyde 2E,4E/Z-decadienal (DD), and a volatile halocarbon (BrCN) that mediate trophic-level interactions in marine diatoms. Induction of cell death in response to DD was mediated by oxidation of mitochondrial EGSH and was reversible by application of GSH only within a narrow time frame. We found that cell fate can be accurately predicted by a distinct life-death threshold of mitochondrial EGSH (−335 mV). We propose that compartmentalized redox-based signaling can integrate the input of diverse environmental cues and will determine cell fate decisions as part of algal acclimation to stress conditions. PMID:25083933

  2. Role of DNA and RNA N6-Adenine Methylation in Regulating Stem Cell Fate.

    Science.gov (United States)

    Wu, Yunshu; Zhou, Chenchen; Yuan, Quan

    2018-01-01

    Epigenetic modifications have been evidenced to participate in eukaryotic stem cell fate decision. Among the most studied, 5-methylcytosine (m5C) and its derivatives are wellestablished epigenetic codes that play important roles in stem cell pluripotency and differentiation. Based on improved detection techniques, recent studies have succeeded in defining N6-adenine methylation (m6A) in eukaryotic DNA and RNA. The abundant m6A methylation in RNA was shown to be involved in multiple cellular metabolisms while the presence and functional potential of DNA m6A methylation in different species advanced our knowledge in the m6A-mediated biological processes. m6A modification has been observed during embryogenesis and has been proposed to fine-tune stem cell regulation. The m6A methyltransferases and demethylases work together to control the dynamic state of m6A marks in genomic DNA and RNA to ensure proper cell fate transition and determination, which are vital to the development and survival of eukaryotes. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Cytokine Secreting Microparticles Engineer the Fate and the Effector Functions of T-Cells.

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    Majedi, Fatemeh S; Hasani-Sadrabadi, Mohammad Mahdi; Kidani, Yoko; Thauland, Timothy J; Moshaverinia, Alireza; Butte, Manish J; Bensinger, Steven J; Bouchard, Louis-S

    2018-01-08

    T-cell immunotherapy is a promising approach for cancer, infection, and autoimmune diseases. However, significant challenges hamper its therapeutic potential, including insufficient activation, delivery, and clonal expansion of T-cells into the tumor environment. To facilitate T-cell activation and differentiation in vitro, core-shell microparticles are developed for sustained delivery of cytokines. These particles are enriched by heparin to enable a steady release of interleukin-2 (IL-2), the major T-cell growth factor, over 10+ d. The controlled delivery of cytokines is used to steer lineage specification of cultured T-cells. This approach enables differentiation of T-cells into central memory and effector memory subsets. It is shown that the sustained release of stromal cell-derived factor 1α could accelerate T-cell migration. It is demonstrated that CD4+ T-cells could be induced to high concentrations of regulatory T-cells through controlled release of IL-2 and transforming growth factor beta. It is found that CD8+ T-cells that received IL-2 from microparticles are more likely to gain effector functions as compared with traditional administration of IL-2. Culture of T-cells within 3D scaffolds that contain IL-2-secreting microparticles enhances proliferation as compared with traditional, 2D approaches. This yield a new method to control the fate of T-cells and ultimately to new strategies for immune therapy. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Phenotypic Plasticity and Cell Fate Decisions in Cancer: Insights from Dynamical Systems Theory.

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    Jia, Dongya; Jolly, Mohit Kumar; Kulkarni, Prakash; Levine, Herbert

    2017-06-22

    Waddington's epigenetic landscape, a famous metaphor in developmental biology, depicts how a stem cell progresses from an undifferentiated phenotype to a differentiated one. The concept of "landscape" in the context of dynamical systems theory represents a high-dimensional space, in which each cell phenotype is considered as an "attractor" that is determined by interactions between multiple molecular players, and is buffered against environmental fluctuations. In addition, biological noise is thought to play an important role during these cell-fate decisions and in fact controls transitions between different phenotypes. Here, we discuss the phenotypic transitions in cancer from a dynamical systems perspective and invoke the concept of "cancer attractors"-hidden stable states of the underlying regulatory network that are not occupied by normal cells. Phenotypic transitions in cancer occur at varying levels depending on the context. Using epithelial-to-mesenchymal transition (EMT), cancer stem-like properties, metabolic reprogramming and the emergence of therapy resistance as examples, we illustrate how phenotypic plasticity in cancer cells enables them to acquire hybrid phenotypes (such as hybrid epithelial/mesenchymal and hybrid metabolic phenotypes) that tend to be more aggressive and notoriously resilient to therapies such as chemotherapy and androgen-deprivation therapy. Furthermore, we highlight multiple factors that may give rise to phenotypic plasticity in cancer cells, such as (a) multi-stability or oscillatory behaviors governed by underlying regulatory networks involved in cell-fate decisions in cancer cells, and (b) network rewiring due to conformational dynamics of intrinsically disordered proteins (IDPs) that are highly enriched in cancer cells. We conclude by discussing why a therapeutic approach that promotes "recanalization", i.e., the exit from "cancer attractors" and re-entry into "normal attractors", is more likely to succeed rather than a

  5. The strength of indecisiveness: oscillatory behavior for better cell fate determination.

    Science.gov (United States)

    Lahav, Galit

    2004-12-21

    Oscillatory behavior is very common in many cellular responses. Recently, two pathways involved in response to cell stress, the p53 and nuclear factor kappa B signaling pathways, have been found to show oscillatory behavior. At first sight, there would seem to be no reason for signaling pathways of this type to require oscillations. Recent single-cell studies indicate that oscillatory behavior may be used to allow repeated testing for the continued existence of a signal. I argue that oscillations increase cellular response sensitivity and flexibility by allowing the cell to integrate the results of many periodical evaluations of the signal before making an eventual decision about cell fate, thus reducing the risk of premature commitment.

  6. Energy metabolic pathways control the fate and function of myeloid immune cells.

    Science.gov (United States)

    Al-Khami, Amir A; Rodriguez, Paulo C; Ochoa, Augusto C

    2017-08-01

    The past decade has seen a significant interest in investigating the intracellular metabolism of cells of the immune system. This has increased the realization that immune cells endure metabolic reprogramming upon responding to pathogen-derived or inflammatory signals. More importantly, not only does this metabolic switch provide for the bioenergetic and biosynthetic demands but also it, in a highly specific manner, determines the cellular fate and function. In this review, we discuss the metabolic aspects that regulate the differentiation and function of myeloid cells, pivotal for both innate and adaptive immunity. The manipulation of these pathways can alter the function of these cells and therefore, could provide novel therapeutic approaches in cancer and other chronic inflammatory conditions. © Society for Leukocyte Biology.

  7. p53-regulated autophagy is controlled by glycolysis and determines cell fate.

    Science.gov (United States)

    Duan, Lei; Perez, Ricardo E; Davaadelger, Batzaya; Dedkova, Elena N; Blatter, Lothar A; Maki, Carl G

    2015-09-15

    The tumor suppressor p53 regulates downstream targets that determine cell fate. Canonical p53 functions include inducing apoptosis, growth arrest, and senescence. Non-canonical p53 functions include its ability to promote or inhibit autophagy and its ability to regulate metabolism. The extent to which autophagy and/or metabolic regulation determines cell fate by p53 is unclear. To address this, we compared cells resistant or sensitive to apoptosis by the p53 activator Nutlin-3a. In resistant cells, glycolysis was maintained upon Nutlin-3a treatment, and activated p53 promoted prosurvival autophagy. In contrast, in apoptosis sensitive cells activated p53 increased superoxide levels and inhibited glycolysis through repression of glycolytic pathway genes. Glycolysis inhibition and increased superoxide inhibited autophagy by repressing ATG genes essential for autophagic vesicle maturation. Inhibiting glycolysis increased superoxide and blocked autophagy in apoptosis-resistant cells, causing p62-dependent caspase-8 activation. Finally, treatment with 2-DG or the autophagy inhibitors chloroquine or bafilomycin A1 sensitized resistant cells to Nutlin-3a-induced apoptosis. Together, these findings reveal novel links between glycolysis and autophagy that determine apoptosis-sensitivity in response to p53. Specifically, the findings indicate 1) that glycolysis plays an essential role in autophagy by limiting superoxide levels and maintaining expression of ATG genes required for autophagic vesicle maturation, 2) that p53 can promote or inhibit autophagy depending on the status of glycolysis, and 3) that inhibiting protective autophagy can expand the breadth of cells susceptible to Nutlin-3a induced apoptosis.

  8. A novel mouse model for tracking the fate of CXCR5-expressing T cells.

    Science.gov (United States)

    Takebe, Tomo; Sakamoto, Kazuki; Higami, Yoshikazu; Harada, Yohsuke

    2018-01-08

    The germinal center (GC) reaction, a critical process in the humoral immune response, requires follicular helper T (Tfh) cells. Tfh cells express the master transcription factor Bcl6 and chemokine receptor CXCR5, which enable them to migrate from the T cell zone to B cell follicles and interact with GC B cells. However, CXCR5 is downregulated when Tfh cells become memory cells. Therefore, it is difficult to track Tfh cells continuously in vivo. In this study, we generated a mouse strain, Cxcr5CreERT2R26Tomato, in which the fluorescent protein tdTomato is inducibly expressed in CXCR5+ cells by tamoxifen administration. After the oral administration of tamoxifen, most Tfh cells in Peyer's patches (PP) from Cxcr5CreERT2R26Tomato mice were tdTomato+. To track antigen-specific Tfh cells in vivo, OVA-specific OT-II T cells derived from Cxcr5CreERT2R26Tomato mice were transferred to wild-type mice, and the recipient mice were immunized with OVA followed by tamoxifen administration. CXCR5+ T cells became tdTomato+ and were mainly located in B cell follicles and GC areas 8 days after immunization. Four weeks after immunization, tdTomato+ OT-II T cells migrated from B cell follicles to the T-B border area and T cell zone after CXCR5 downregulation and CCR7 upregulation. These results indicate that Cxcr5CreERT2R26Tomato mice are a useful tool for studying the cell fate of differentiated Tfh cells in vivo and therefore have implications for the development of therapeutic strategies for infectious and autoimmune diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Single-Cell Profiling of Epigenetic Modifiers Identifies PRDM14 as an Inducer of Cell Fate in the Mammalian Embryo

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    Adam Burton

    2013-11-01

    Full Text Available Cell plasticity or potency is necessary for the formation of multiple cell types. The mechanisms underlying this plasticity are largely unknown. Preimplantation mouse embryos undergo drastic changes in cellular potency, starting with the totipotent zygote through to the formation of the pluripotent inner cell mass (ICM and differentiated trophectoderm in the blastocyst. Here, we set out to identify and functionally characterize chromatin modifiers that define the transitions of potency and cell fate in the mouse embryo. Using a quantitative microfluidics approach in single cells, we show that developmental transitions are marked by distinctive combinatorial profiles of epigenetic modifiers. Pluripotent cells of the ICM are distinct from their differentiated trophectoderm counterparts. We show that PRDM14 is heterogeneously expressed in 4-cell-stage embryos. Forced expression of PRDM14 at the 2-cell stage leads to increased H3R26me2 and can induce a pluripotent ICM fate. Our results shed light on the epigenetic networks that govern cellular potency and identity in vivo.

  10. A Multistate Toggle Switch Defines Fungal Cell Fates and Is Regulated by Synergistic Genetic Cues.

    Directory of Open Access Journals (Sweden)

    Matthew Z Anderson

    2016-10-01

    Full Text Available Heritable epigenetic changes underlie the ability of cells to differentiate into distinct cell types. Here, we demonstrate that the fungal pathogen Candida tropicalis exhibits multipotency, undergoing stochastic and reversible switching between three cellular states. The three cell states exhibit unique cellular morphologies, growth rates, and global gene expression profiles. Genetic analysis identified six transcription factors that play key roles in regulating cell differentiation. In particular, we show that forced expression of Wor1 or Efg1 transcription factors can be used to manipulate transitions between all three cell states. A model for tristability is proposed in which Wor1 and Efg1 are self-activating but mutually antagonistic transcription factors, thereby forming a symmetrical self-activating toggle switch. We explicitly test this model and show that ectopic expression of WOR1 can induce white-to-hybrid-to-opaque switching, whereas ectopic expression of EFG1 drives switching in the opposite direction, from opaque-to-hybrid-to-white cell states. We also address the stability of induced cell states and demonstrate that stable differentiation events require ectopic gene expression in combination with chromatin-based cues. These studies therefore experimentally test a model of multistate stability and demonstrate that transcriptional circuits act synergistically with chromatin-based changes to drive cell state transitions. We also establish close mechanistic parallels between phenotypic switching in unicellular fungi and cell fate decisions during stem cell reprogramming.

  11. DMPD: Nitric oxide and cell viability in inflammatory cells: a role for NO inmacrophage function and fate. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15691589 Nitric oxide and cell viability in inflammatory cells: a role for NO inmacrophage function...(.png) (.svg) (.html) (.csml) Show Nitric oxide and cell viability in inflammatory cells: a role for NO inmacrophage function...ty in inflammatory cells: a role for NO inmacrophage function and fate. Authors Bosca L, Zeini M, Traves PG,

  12. The fate of chrysotile-induced multipolar mitosis and aneuploid population in cultured lung cancer cells.

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    Beatriz de Araujo Cortez

    Full Text Available Chrysotile is one of the six types of asbestos, and it is the only one that can still be commercialized in many countries. Exposure to other types of asbestos has been associated with serious diseases, such as lung carcinomas and pleural mesotheliomas. The association of chrysotile exposure with disease is controversial. However, in vitro studies show the mutagenic potential of chrysotile, which can induce DNA and cell damage. The present work aimed to analyze alterations in lung small cell carcinoma cultures after 48 h of chrysotile exposure, followed by 2, 4 and 8 days of recovery in fiber-free culture medium. Some alterations, such as aneuploid cell formation, increased number of cells in G2/M phase and cells in multipolar mitosis were observed even after 8 days of recovery. The presence of chrysotile fibers in the cell cultures was detected and cell morphology was observed by laser scanning confocal microscopy. After 4 and 8 days of recovery, only a few chrysotile fragments were present in some cells, and the cellular morphology was similar to that of control cells. Cells transfected with the GFP-tagged α-tubulin plasmid were treated with chrysotile for 24 or 48 h and cells in multipolar mitosis were observed by time-lapse microscopy. Fates of these cells were established: retention in metaphase, cell death, progression through M phase generating more than two daughter cells or cell fusion during telophase or cytokinesis. Some of them were related to the formation of aneuploid cells and cells with abnormal number of centrosomes.

  13. Conversion of neurons and glia to external-cell fates in the external sensory organs of Drosophila hamlet mutants by a cousin-cousin cell-type respecification.

    Science.gov (United States)

    Moore, Adrian W; Roegiers, Fabrice; Jan, Lily Y; Jan, Yuh-Nung

    2004-03-15

    The Drosophila external sensory organ forms in a lineage elaborating from a single precursor cell via a stereotypical series of asymmetric divisions. HAMLET transcription factor expression demarcates the lineage branch that generates two internal cell types, the external sensory neuron and thecogen. In HAMLET mutant organs, these internal cells are converted to external cells via an unprecedented cousin-cousin cell-fate respecification event. Conversely, ectopic HAMLET expression in the external cell branch leads to internal cell production. The fate-determining signals NOTCH and PAX2 act at multiple stages of lineage elaboration and HAMLET acts to modulate their activity in a branch-specific manner.

  14. Arabidopsis LEAFY COTYLEDON1 controls cell fate determination during post-embryonic development

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    Mingkun eHuang

    2015-11-01

    Full Text Available Arabidopsis LEAFY COTYLEDON1 (LEC1 transcription factor is a master regulator that shapes plant embryo development and post-embryonic seedling establishment. Loss-of-function of LEC1 alters the cotyledon identity, causing the formation of ectopic trichomes, which does not occur in wild-type seedlings, implying that LEC1 might regulate embryonic cell fate determination during post-embryonic development. To test this hypothesis, we compared the expression of trichome development-related genes between the wild-type and the lec1 mutant. We observed that transcripts of GL1, GL2 and GL3, genes encoding the positive regulators in trichome development, were significantly upregulated, while the TCL2, ETC1 and ETC2 genes, encoding the negative regulators in trichome development, were downregulated in the lec1 mutant. Furthermore, overexpression of LEC1 activated the expressions of TCL2, CPC and ETC1, resulting in production of cotyledonary leaves with no or fewer trichomes during vegetative development. In addition, we demonstrated that LEC1 interacts with TCL2 in yeast and in vitro. A genetic experiment showed that loss-of-function of GL2 rescued the ectopic trichome formation in the lec1 mutant. These findings strongly support that LEC1 regulates trichome development, providing direct evidence for the role of LEC1 in cell fate determination during post-embryonic development.

  15. An adaptive molecular timer in p53-meidated cell fate decision

    Science.gov (United States)

    Zhang, Xiao-Peng; Wang, Ping; Liu, Feng; Wang, Wei

    The tumor suppressor p53 decides cellular outcomes in the DNA damage response. It is intriguing to explore the link between p53 dynamics and cell fates. We developed a theoretical model of p53 signaling network to clarify the mechanism of cell fate decision mediated by its dynamics. We found that the interplay between p53-Mdm2 negative feedback loop and p53-PTEN-Mdm2 positive feedback loop shapes p53 dynamics. Depending on the intensity of DNA damage, p53 shows three modes of dynamics: persistent pulses, two-phase dynamics with pulses followed by sustained high levels and straightforward high levels. Especially, p53 shows two-phase dynamics upon moderated damage and the required number of p53 pulses before apoptosis induction decreases with increasing DNA damage. Our results suggested there exists an adaptive molecular timer that determines whether and when the apoptosis switch should be triggered. We clarified the mechanism behind the switching of p53 dynamical modes by bifurcation analysis. Moreover, we reproduced the experimental results that drug additions alter p53 pulses to sustained p53 activation and leads to senescence. Our work may advance the understanding the significance of p53 dynamics in tumor suppression. This work was supported by National Natural Science Foundation of China (Nos. 11175084, 11204126 and 31361163003).

  16. Activin/nodal signaling switches the terminal fate of human embryonic stem cell-derived trophoblasts.

    Science.gov (United States)

    Sarkar, Prasenjit; Randall, Shan M; Collier, Timothy S; Nero, Anthony; Russell, Teal A; Muddiman, David C; Rao, Balaji M

    2015-04-03

    Human embryonic stem cells (hESCs) have been routinely treated with bone morphogenetic protein and/or inhibitors of activin/nodal signaling to obtain cells that express trophoblast markers. Trophoblasts can terminally differentiate to either extravillous trophoblasts or syncytiotrophoblasts. The signaling pathways that govern the terminal fate of these trophoblasts are not understood. We show that activin/nodal signaling switches the terminal fate of these hESC-derived trophoblasts. Inhibition of activin/nodal signaling leads to formation of extravillous trophoblast, whereas loss of activin/nodal inhibition leads to the formation of syncytiotrophoblasts. Also, the ability of hESCs to form bona fide trophoblasts has been intensely debated. We have examined hESC-derived trophoblasts in the light of stringent criteria that were proposed recently, such as hypomethylation of the ELF5-2b promoter region and down-regulation of HLA class I antigens. We report that trophoblasts that possess these properties can indeed be obtained from hESCs. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Activin/Nodal Signaling Switches the Terminal Fate of Human Embryonic Stem Cell-derived Trophoblasts*

    Science.gov (United States)

    Sarkar, Prasenjit; Randall, Shan M.; Collier, Timothy S.; Nero, Anthony; Russell, Teal A.; Muddiman, David C.; Rao, Balaji M.

    2015-01-01

    Human embryonic stem cells (hESCs) have been routinely treated with bone morphogenetic protein and/or inhibitors of activin/nodal signaling to obtain cells that express trophoblast markers. Trophoblasts can terminally differentiate to either extravillous trophoblasts or syncytiotrophoblasts. The signaling pathways that govern the terminal fate of these trophoblasts are not understood. We show that activin/nodal signaling switches the terminal fate of these hESC-derived trophoblasts. Inhibition of activin/nodal signaling leads to formation of extravillous trophoblast, whereas loss of activin/nodal inhibition leads to the formation of syncytiotrophoblasts. Also, the ability of hESCs to form bona fide trophoblasts has been intensely debated. We have examined hESC-derived trophoblasts in the light of stringent criteria that were proposed recently, such as hypomethylation of the ELF5-2b promoter region and down-regulation of HLA class I antigens. We report that trophoblasts that possess these properties can indeed be obtained from hESCs. PMID:25670856

  18. β-Catenin Signaling Biases Multipotent Lingual Epithelial Progenitors to Differentiate and Acquire Specific Taste Cell Fates.

    Directory of Open Access Journals (Sweden)

    Dany Gaillard

    2015-05-01

    Full Text Available Continuous taste bud cell renewal is essential to maintain taste function in adults; however, the molecular mechanisms that regulate taste cell turnover are unknown. Using inducible Cre-lox technology, we show that activation of β-catenin signaling in multipotent lingual epithelial progenitors outside of taste buds diverts daughter cells from a general epithelial to a taste bud fate. Moreover, while taste buds comprise 3 morphological types, β-catenin activation drives overproduction of primarily glial-like Type I taste cells in both anterior fungiform (FF and posterior circumvallate (CV taste buds, with a small increase in Type II receptor cells for sweet, bitter and umami, but does not alter Type III sour detector cells. Beta-catenin activation in post-mitotic taste bud precursors likewise regulates cell differentiation; forced activation of β-catenin in these Shh+ cells promotes Type I cell fate in both FF and CV taste buds, but likely does so non-cell autonomously. Our data are consistent with a model where β-catenin signaling levels within lingual epithelial progenitors dictate cell fate prior to or during entry of new cells into taste buds; high signaling induces Type I cells, intermediate levels drive Type II cell differentiation, while low levels may drive differentiation of Type III cells.

  19. β-Catenin Signaling Biases Multipotent Lingual Epithelial Progenitors to Differentiate and Acquire Specific Taste Cell Fates

    Science.gov (United States)

    Gaillard, Dany; Xu, Mingang; Liu, Fei; Millar, Sarah E.; Barlow, Linda A.

    2015-01-01

    Continuous taste bud cell renewal is essential to maintain taste function in adults; however, the molecular mechanisms that regulate taste cell turnover are unknown. Using inducible Cre-lox technology, we show that activation of β-catenin signaling in multipotent lingual epithelial progenitors outside of taste buds diverts daughter cells from a general epithelial to a taste bud fate. Moreover, while taste buds comprise 3 morphological types, β-catenin activation drives overproduction of primarily glial-like Type I taste cells in both anterior fungiform (FF) and posterior circumvallate (CV) taste buds, with a small increase in Type II receptor cells for sweet, bitter and umami, but does not alter Type III sour detector cells. Beta-catenin activation in post-mitotic taste bud precursors likewise regulates cell differentiation; forced activation of β-catenin in these Shh+ cells promotes Type I cell fate in both FF and CV taste buds, but likely does so non-cell autonomously. Our data are consistent with a model where β-catenin signaling levels within lingual epithelial progenitors dictate cell fate prior to or during entry of new cells into taste buds; high signaling induces Type I cells, intermediate levels drive Type II cell differentiation, while low levels may drive differentiation of Type III cells. PMID:26020789

  20. Cell-type-specific predictive network yields novel insights into mouse embryonic stem cell self-renewal and cell fate.

    Directory of Open Access Journals (Sweden)

    Karen G Dowell

    Full Text Available Self-renewal, the ability of a stem cell to divide repeatedly while maintaining an undifferentiated state, is a defining characteristic of all stem cells. Here, we clarify the molecular foundations of mouse embryonic stem cell (mESC self-renewal by applying a proven Bayesian network machine learning approach to integrate high-throughput data for protein function discovery. By focusing on a single stem-cell system, at a specific developmental stage, within the context of well-defined biological processes known to be active in that cell type, we produce a consensus predictive network that reflects biological reality more closely than those made by prior efforts using more generalized, context-independent methods. In addition, we show how machine learning efforts may be misled if the tissue specific role of mammalian proteins is not defined in the training set and circumscribed in the evidential data. For this study, we assembled an extensive compendium of mESC data: ∼2.2 million data points, collected from 60 different studies, under 992 conditions. We then integrated these data into a consensus mESC functional relationship network focused on biological processes associated with embryonic stem cell self-renewal and cell fate determination. Computational evaluations, literature validation, and analyses of predicted functional linkages show that our results are highly accurate and biologically relevant. Our mESC network predicts many novel players involved in self-renewal and serves as the foundation for future pluripotent stem cell studies. This network can be used by stem cell researchers (at http://StemSight.org to explore hypotheses about gene function in the context of self-renewal and to prioritize genes of interest for experimental validation.

  1. Cell-type-specific predictive network yields novel insights into mouse embryonic stem cell self-renewal and cell fate.

    Science.gov (United States)

    Dowell, Karen G; Simons, Allen K; Wang, Zack Z; Yun, Kyuson; Hibbs, Matthew A

    2013-01-01

    Self-renewal, the ability of a stem cell to divide repeatedly while maintaining an undifferentiated state, is a defining characteristic of all stem cells. Here, we clarify the molecular foundations of mouse embryonic stem cell (mESC) self-renewal by applying a proven Bayesian network machine learning approach to integrate high-throughput data for protein function discovery. By focusing on a single stem-cell system, at a specific developmental stage, within the context of well-defined biological processes known to be active in that cell type, we produce a consensus predictive network that reflects biological reality more closely than those made by prior efforts using more generalized, context-independent methods. In addition, we show how machine learning efforts may be misled if the tissue specific role of mammalian proteins is not defined in the training set and circumscribed in the evidential data. For this study, we assembled an extensive compendium of mESC data: ∼2.2 million data points, collected from 60 different studies, under 992 conditions. We then integrated these data into a consensus mESC functional relationship network focused on biological processes associated with embryonic stem cell self-renewal and cell fate determination. Computational evaluations, literature validation, and analyses of predicted functional linkages show that our results are highly accurate and biologically relevant. Our mESC network predicts many novel players involved in self-renewal and serves as the foundation for future pluripotent stem cell studies. This network can be used by stem cell researchers (at http://StemSight.org) to explore hypotheses about gene function in the context of self-renewal and to prioritize genes of interest for experimental validation.

  2. ECM-dependent HIF induction directs trophoblast stem cell fate via LIMK1-mediated cytoskeletal rearrangement.

    Directory of Open Access Journals (Sweden)

    Hwa J Choi

    Full Text Available The Hypoxia-inducible Factor (HIF family of transcriptional regulators coordinates the expression of dozens of genes in response to oxygen deprivation. Mammalian development occurs in a hypoxic environment and HIF-null mice therefore die in utero due to multiple embryonic and placental defects. Mouse embryonic stem cells do not differentiate into placental cells; therefore, trophoblast stem cells (TSCs are used to study mouse placental development. Consistent with a requirement for HIF activity during placental development in utero, TSCs derived from HIF-null mice exhibit severe differentiation defects and fail to form trophoblast giant cells (TGCs in vitro. Interestingly, differentiating TSCs induce HIF activity independent of oxygen tension via unclear mechanisms. Here, we show that altering the extracellular matrix (ECM composition upon which TSCs are cultured changes their differentiation potential from TGCs to multinucleated syncytiotropholasts (SynTs and blocks oxygen-independent HIF induction. We further find that modulation of Mitogen Activated Protein Kinase Kinase-1/2 (MAP2K1/2, MEK-1/2 signaling by ECM composition is responsible for this effect. In the absence of ECM-dependent cues, hypoxia-signaling pathways activate this MAPK cascade to drive HIF induction and redirect TSC fate along the TGC lineage. In addition, we show that integrity of the microtubule and actin cytoskeleton is critical for TGC fate determination. HIF-2α ensures TSC cytoskeletal integrity and promotes invasive TGC formation by interacting with c-MYC to induce non-canonical expression of Lim domain kinase 1-an enzyme that regulates microtubule and actin stability, as well as cell invasion. Thus, we find that HIF can integrate positional and metabolic cues from within the TSC niche to regulate placental development by modulating the cellular cytoskeleton via non-canonical gene expression.

  3. The neural stem cell fate determinant TRIM32 regulates complex behavioral traits

    Directory of Open Access Journals (Sweden)

    Anna-Lena eHillje

    2015-03-01

    Full Text Available In mammals, new neurons are generated throughout the entire lifespan in two restricted areas of the brain, the dentate gyrus (DG of the hippocampus and the subventricular zone (SVZ – olfactory bulb (OB system. In both regions newborn neurons display unique properties that clearly distinguish them from mature neurons. Enhanced excitability and increased synaptic plasticity enables them to add specific properties to information processing by modulating the existing local circuitry of already established mature neurons. Hippocampal neurogenesis has been suggested to play a role in spatial-navigation learning, spatial memory and spatial pattern separation. Cumulative evidences implicate that adult-born OB neurons contribute to learning processes and odor memory. We recently demonstrated that the cell fate determinant TRIM32 is upregulated in differentiating neuroblasts of the SVZ-OB system in the adult mouse brain. The absence of TRIM32 leads to increased progenitor cell proliferation and less cell death. Both effects accumulate in an overproduction of adult-generated OB neurons. Here, we present novel data from behavioral studies showing that such an enhancement of OB neurogenesis not necessarily leads to increased olfactory performance but in contrast even results in impaired olfactory capabilities. In addition, we show at the cellular level that TRIM32 protein levels increase during differentiation of neural stem cells. At the molecular level, several metabolic intermediates that are connected to glycolysis, glycine or cysteine metabolism are deregulated in TRIM32 knockout mice brain tissue. These metabolomics pathways are directly or indirectly linked to anxiety or depression like behavior. In summary, our study provides comprehensive data on how the impairment of neurogenesis caused by the loss of the cell fate determinant TRIM32 causes a decrease of olfactory performance as well as a deregulation of metabolomic pathways that are linked to

  4. Bar represses dPax2 and decapentaplegic to regulate cell fate and morphogenetic cell death in Drosophila eye.

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    Jongkyun Kang

    Full Text Available The coordinated regulation of cell fate and cell survival is crucial for normal pattern formation in developing organisms. In Drosophila compound eye development, crystalline arrays of hexagonal ommatidia are established by precise assembly of diverse cell types, including the photoreceptor cells, cone cells and interommatidial (IOM pigment cells. The molecular basis for controlling the number of cone and IOM pigment cells during ommatidial pattern formation is not well understood. Here we present evidence that BarH1 and BarH2 homeobox genes are essential for eye patterning by inhibiting excess cone cell differentiation and promoting programmed death of IOM cells. Specifically, we show that loss of Bar from the undifferentiated retinal precursor cells leads to ectopic expression of Prospero and dPax2, two transcription factors essential for cone cell specification, resulting in excess cone cell differentiation. We also show that loss of Bar causes ectopic expression of the TGFβ homolog Decapentaplegic (Dpp posterior to the morphogenetic furrow in the larval eye imaginal disc. The ectopic Dpp expression is not responsible for the formation of excess cone cells in Bar loss-of-function mutant eyes. Instead, it causes reduction in IOM cell death in the pupal stage by antagonizing the function of pro-apoptotic gene reaper. Taken together, this study suggests a novel regulatory mechanism in the control of developmental cell death in which the repression of Dpp by Bar in larval eye disc is essential for IOM cell death in pupal retina.

  5. Concentration-dependent effect of nerve growth factor on cell fate determination of neural progenitors.

    Science.gov (United States)

    Zhang, Lei; Jiang, Hui; Hu, Zhengqing

    2011-10-01

    Stem cell-based spiral ganglion neuron (SGN) replacement therapy has been proposed to be a promising strategy to restore hearing either via replacing degenerated neurons or by improving the efficacy of cochlear implants which rely on functional neurons. However, lack of suitable donor cells and low survival rate of implanted cells are the major obstacles to successful implementation of therapeutic transplantation. The present study investigated the potential of mouse inner ear statoacoustic ganglion (SAG)-derived neural progenitors (NPs) to differentiate toward SGN-like glutamatergic cells and the influence to cell survival and differentiation when nerve growth factor (NGF) was supplied. We found that SAG-NPs could form neurospheres, proliferate, and differentiate into cells expressing neuronal protein neurofilament and β-III tubulin. NGF affected the cell fate of SAG-NP in a concentration-dependent manner in vitro. Low concentration of NGF (2-5 ng/mL) promoted cell proliferation. Medium concentration of NGF (20-40 ng/mL) stimulated cells to differentiate into bi-polar SGN-like cells expressing glutamatergic proteins. High concentration of NGF (100 ng/mL) could rescue cells from induced apoptosis. In the in vivo study, NGF (100 ng/mL) dramatically enhanced SAG-NP survival rate after implantation into adult mammalian inner ear. This finding raises the possibility to further induce these NPs to differentiate into SGN-like neurons in future in vivo study. In conclusion, given the capability of proliferation and differentiation into SGN-like cells with the supplement of NGF in vitro, SAG-NPs can serve as donor cells in stem cell-based SGN replacement therapy. NGF improved the survival of SAG-NPs not only in vitro but also in vivo.

  6. Sensitivity analysis of intracellular signaling pathway kinetics predicts targets for stem cell fate control.

    Directory of Open Access Journals (Sweden)

    Alborz Mahdavi

    2007-07-01

    Full Text Available Directing stem cell fate requires knowledge of how signaling networks integrate temporally and spatially segregated stimuli. We developed and validated a computational model of signal transducer and activator of transcription-3 (Stat3 pathway kinetics, a signaling network involved in embryonic stem cell (ESC self-renewal. Our analysis identified novel pathway responses; for example, overexpression of the receptor glycoprotein-130 results in reduced pathway activation and increased ESC differentiation. We used a systematic in silico screen to identify novel targets and protein interactions involved in Stat3 activation. Our analysis demonstrates that signaling activation and desensitization (the inability to respond to ligand restimulation is regulated by balancing the activation state of a distributed set of parameters including nuclear export of Stat3, nuclear phosphatase activity, inhibition by suppressor of cytokine signaling, and receptor trafficking. This knowledge was used to devise a temporally modulated ligand delivery strategy that maximizes signaling activation and leads to enhanced ESC self-renewal.

  7. Thidiazuron Triggers Morphogenesis in Rosa canina L. Protocorm-like bodies by Changing Incipient Cell Fate

    Directory of Open Access Journals (Sweden)

    Kou eYaping

    2016-05-01

    Full Text Available Thidiazuron (N-phenyl-N'-1,2,3-thiadiazol-5-ylurea; TDZ is an artificial plant growth regulator that is widely used in plant tissue culture. Protocorm-like bodies (PLBs induced by TDZ serve as an efficient and rapid in vitro regeneration system in Rosa species. Despite this, the mechanism of PLB induction remains relatively unclear. TDZ, which can affect the level of endogenous auxins and cytokinins, converts the cell fate of rhizoid tips and triggers PLB formation and plantlet regeneration in Rosa canina L. In callus-rhizoids, which are rhizoids that co-develop from callus, auxin and a Z-type cytokinin accumulated after applying TDZ, and transcription of the auxin transporter gene RcPIN1 was repressed. The expression of RcARF4, RcRR1, RcCKX2, RcCKX3, and RcLOG1 increased in callus-rhizoids and rhizoid tips while the transcription of an auxin response factor (RcARF1 and auxin transport proteins (RcPIN2, RcPIN3 decreased in callus-rhizoids but increased in rhizoid tips. In situ hybridization of rhizoids showed that RcWUS and RcSERK1 were highly expressed in columella cells and root stem cells resulting in the conversion of cell fate into shoot apical meristems or embryogenic callus. In addition, transgenic XVE::RcWUS lines showed repressed RcWUS overexpression while RcWUS had no effect on PLB morphogenesis. Furthermore, higher expression of the root stem cell marker RcWOX5 and root stem cell maintenance regulator genes RcPLT1 and RcPLT2 indicated the presence of a dedifferentiation developmental pathway in the stem cell niche of rhizoids. Viewed together, our results indicate that different cells in rhizoid tips acquired regeneration competence after induction by TDZ. A novel developmental pathway containing different cell types during PLB formation was identified by analyzing the endogenous auxin and cytokinin content. This study also provides a deeper understanding of the mechanisms underlying in vitro regeneration in Rosa.

  8. Thidiazuron Triggers Morphogenesis in Rosa canina L. Protocorm-Like Bodies by Changing Incipient Cell Fate.

    Science.gov (United States)

    Kou, Yaping; Yuan, Cunquan; Zhao, Qingcui; Liu, Guoqin; Nie, Jing; Ma, Zhimin; Cheng, Chenxia; Teixeira da Silva, Jaime A; Zhao, Liangjun

    2016-01-01

    Thidiazuron (N-phenyl-N'-1,2,3-thiadiazol-5-ylurea; TDZ) is an artificial plant growth regulator that is widely used in plant tissue culture. Protocorm-like bodies (PLBs) induced by TDZ serve as an efficient and rapid in vitro regeneration system in Rosa species. Despite this, the mechanism of PLB induction remains relatively unclear. TDZ, which can affect the level of endogenous auxins and cytokinins, converts the cell fate of rhizoid tips and triggers PLB formation and plantlet regeneration in Rosa canina L. In callus-rhizoids, which are rhizoids that co-develop from callus, auxin and a Z-type cytokinin accumulated after applying TDZ, and transcription of the auxin transporter gene RcPIN1 was repressed. The expression of RcARF4, RcRR1, RcCKX2, RcCKX3, and RcLOG1 increased in callus-rhizoids and rhizoid tips while the transcription of an auxin response factor (RcARF1) and auxin transport proteins (RcPIN2, RcPIN3) decreased in callus-rhizoids but increased in rhizoid tips. In situ hybridization of rhizoids showed that RcWUS and RcSERK1 were highly expressed in columella cells and root stem cells resulting in the conversion of cell fate into shoot apical meristems or embryogenic callus. In addition, transgenic XVE::RcWUS lines showed repressed RcWUS overexpression while RcWUS had no effect on PLB morphogenesis. Furthermore, higher expression of the root stem cell marker RcWOX5 and root stem cell maintenance regulator genes RcPLT1 and RcPLT2 indicated the presence of a dedifferentiation developmental pathway in the stem cell niche of rhizoids. Viewed together, our results indicate that different cells in rhizoid tips acquired regeneration competence after induction by TDZ. A novel developmental pathway containing different cell types during PLB formation was identified by analyzing the endogenous auxin and cytokinin content. This study also provides a deeper understanding of the mechanisms underlying in vitro regeneration in Rosa.

  9. The Fate of a Normal Human Cell Traversed by a Single Charged Particle

    Science.gov (United States)

    Fournier, C.; Zahnreich, S.; Kraft, D.; Friedrich, T.; Voss, K.-O.; Durante, M.; Ritter, S.

    2012-09-01

    The long-term ``fate'' of normal human cells after single hits of charged particles is one of the oldest unsolved issues in radiation protection and cellular radiobiology. Using a high-precision heavy-ion microbeam we could target normal human fibroblasts with exactly one or five carbon ions and measured the early cytogenetic damage and the late behaviour using single-cell cloning. Around 70% of the first cycle cells presented visible aberrations in mFISH after a single ion traversal, and about 5% of the cells were still able to form colonies. In one third of selected high-proliferative colonies we observed clonal (radiation-induced) aberrations. Terminal differentiation and markers of senescence (PCNA, p16) in the descendants of cells traversed by one carbon ion occurred earlier than in controls, but no evidence of radiation-induced chromosomal instability was found. We conclude that cells surviving single-ion traversal, often carrying clonal chromosome aberrations, undergo accelerated senescence but maintain chromosomal stability.

  10. Nontelomeric TRF2-REST interaction modulates neuronal gene silencing and fate of tumor and stem cells.

    Science.gov (United States)

    Zhang, Peisu; Pazin, Michael J; Schwartz, Catherine M; Becker, Kevin G; Wersto, Robert P; Dilley, Caroline M; Mattson, Mark P

    2008-10-14

    Removal of TRF2, a telomere shelterin protein, recapitulates key aspects of telomere attrition including the DNA-damage response and cell-cycle arrest [1]. Distinct from the response of proliferating cells to loss of TRF2 [2, 3], in rodent noncycling cells, TRF2 inhibition promotes differentiation and growth [4, 5]. However, the mechanism that couples telomere gene-silencing features [6-8] to differentiation programs has yet to be elucidated. Here we describe an extratelomeric function of TRF2 in the regulation of neuronal genes mediated by the interaction of TRF2 with repressor element 1-silencing transcription factor (REST), a master repressor of gene networks devoted to neuronal functions [9-12]. TRF2-REST complexes are readily detected by coimmunoprecipitation assays and are localized to aggregated PML-nuclear bodies in undifferentiated pluripotent human NTera2 stem cells. Inhibition of TRF2, either by a dominant-negative mutant or by RNA interference, dissociates TRF2-REST complexes resulting in ubiquitin-proteasomal degradation of REST. Consequentially, REST-targeted neural genes (L1CAM, beta3-tubulin, synaptophysin, and others) are derepressed, resulting in acquisition of neuronal phenotypes. Notably, selective damage to telomeres without affecting TRF2 levels causes neither REST degradation nor cell differentiation. Thus, in addition to protecting telomeres, TRF2 possesses a novel role in stabilization of REST thereby controlling neural tumor and stem cell fate.

  11. The influence of immunosuppressive drugs on neural stem/progenitor cell fate in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Skardelly, Marco, E-mail: Marco.Skardelly@med.uni-tuebingen.de [Department of Neurosurgery, University Hospital, Leipzig (Germany); Translational Centre for Regenerative Medicine, University of Leipzig, Leipzig (Germany); Glien, Anja; Groba, Claudia; Schlichting, Nadine [Department of Neurosurgery, University Hospital, Leipzig (Germany); Kamprad, Manja [Institute of Clinical Immunology, Medical Faculty, University of Leipzig, Leipzig (Germany); Meixensberger, Juergen [Department of Neurosurgery, University Hospital, Leipzig (Germany); Milosevic, Javorina [Translational Centre for Regenerative Medicine, University of Leipzig, Leipzig (Germany)

    2013-12-10

    In allogenic and xenogenic transplantation, adequate immunosuppression plays a major role in graft survival, especially over the long term. The effect of immunosuppressive drugs on neural stem/progenitor cell fate has not been sufficiently explored. The focus of this study is to systematically investigate the effects of the following four different immunotherapeutic strategies on human neural progenitor cell survival/death, proliferation, metabolic activity, differentiation and migration in vitro: (1) cyclosporine A (CsA), a calcineurin inhibitor; (2) everolimus (RAD001), an mTOR-inhibitor; (3) mycophenolic acid (MPA, mycophenolate), an inhibitor of inosine monophosphate dehydrogenase and (4) prednisolone, a steroid. At the minimum effective concentration (MEC), we found a prominent decrease in hNPCs' proliferative capacity (BrdU incorporation), especially for CsA and MPA, and an alteration of the NAD(P)H-dependent metabolic activity. Cell death rate, neurogenesis, gliogenesis and cell migration remained mostly unaffected under these conditions for all four immunosuppressants, except for apoptotic cell death, which was significantly increased by MPA treatment. - Highlights: • Four immunosuppresants (ISs) were tested in human neural progenitor cells in vitro. • Cyclosporine A and mycophenolic acid showed a prominent anti-proliferative activity • Mycophenolic acid exhibited a significant pro-apoptotic effect. • NAD(P)H-dependent metabolic activity was occasionally induced by ISs. • Neuronal differentiation and migration potential remained unaffected by ISs treatment.

  12. Regional signals in the planarian body guide stem cell fate in the presence of genomic instability.

    Science.gov (United States)

    Peiris, T Harshani; Ramirez, Daniel; Barghouth, Paul G; Ofoha, Udokanma; Davidian, Devon; Weckerle, Frank; Oviedo, Néstor J

    2016-05-15

    Cellular fate decisions are influenced by their topographical location in the adult body. For instance, tissue repair and neoplastic growth are greater in anterior than in posterior regions of adult animals. However, the molecular underpinnings of these regional differences are unknown. We identified a regional switch in the adult planarian body upon systemic disruption of homologous recombination with RNA-interference of Rad51 Rad51 knockdown increases DNA double-strand breaks (DSBs) throughout the body, but stem cells react differently depending on their location along the anteroposterior axis. In the presence of extensive DSBs, cells in the anterior part of the body resist death, whereas cells in the posterior region undergo apoptosis. Furthermore, we found that proliferation of cells with DNA damage is induced in the presence of brain tissue and that the retinoblastoma pathway enables overproliferation of cells with DSBs while attending to the demands of tissue growth and repair. Our results implicate both autonomous and non-autonomous mechanisms as key mediators of regional cell behavior and cellular transformation in the adult body. © 2016. Published by The Company of Biologists Ltd.

  13. Human stem cells from single blastomeres reveal pathways of embryonic or trophoblast fate specification.

    Science.gov (United States)

    Zdravkovic, Tamara; Nazor, Kristopher L; Larocque, Nicholas; Gormley, Matthew; Donne, Matthew; Hunkapillar, Nathan; Giritharan, Gnanaratnam; Bernstein, Harold S; Wei, Grace; Hebrok, Matthias; Zeng, Xianmin; Genbacev, Olga; Mattis, Aras; McMaster, Michael T; Krtolica, Ana; Valbuena, Diana; Simón, Carlos; Laurent, Louise C; Loring, Jeanne F; Fisher, Susan J

    2015-12-01

    Mechanisms of initial cell fate decisions differ among species. To gain insights into lineage allocation in humans, we derived ten human embryonic stem cell lines (designated UCSFB1-10) from single blastomeres of four 8-cell embryos and one 12-cell embryo from a single couple. Compared with numerous conventional lines from blastocysts, they had unique gene expression and DNA methylation patterns that were, in part, indicative of trophoblast competence. At a transcriptional level, UCSFB lines from different embryos were often more closely related than those from the same embryo. As predicted by the transcriptomic data, immunolocalization of EOMES, T brachyury, GDF15 and active β-catenin revealed differential expression among blastomeres of 8- to 10-cell human embryos. The UCSFB lines formed derivatives of the three germ layers and CDX2-positive progeny, from which we derived the first human trophoblast stem cell line. Our data suggest heterogeneity among early-stage blastomeres and that the UCSFB lines have unique properties, indicative of a more immature state than conventional lines. © 2015. Published by The Company of Biologists Ltd.

  14. Muscle side population cells from dystrophic or injured muscle adopt a fibro-adipogenic fate.

    Science.gov (United States)

    Penton, Christopher M; Thomas-Ahner, Jennifer M; Johnson, Eric K; McAllister, Cynthia; Montanaro, Federica

    2013-01-01

    Muscle side population (SP) cells are rare multipotent stem cells that can participate in myogenesis and muscle regeneration upon transplantation. While they have been primarily studied for the development of cell-based therapies for Duchenne muscular dystrophy, little is known regarding their non-muscle lineage choices or whether the dystrophic muscle environment affects their ability to repair muscle. Unfortunately, the study of muscle SP cells has been challenged by their low abundance and the absence of specific SP cell markers. To address these issues, we developed culture conditions for the propagation and spontaneous multi-lineage differentiation of muscle SP cells. Using this approach, we show that SP cells from wild type muscle robustly differentiate into satellite cells and form myotubes without requiring co-culture with myogenic cells. Furthermore, this myogenic activity is associated with SP cells negative for immune (CD45) and vascular (CD31) markers but positive for Pax7, Sca1, and the mesenchymal progenitor marker PDGFRα. Additionally, our studies revealed that SP cells isolated from dystrophic or cardiotoxin-injured muscle fail to undergo myogenesis. Instead, these SP cells rapidly expand giving rise to fibroblast and adipocyte progenitors (FAPs) and to their differentiated progeny, fibroblasts and adipocytes. Our findings indicate that muscle damage affects the lineage choices of muscle SP cells, promoting their differentiation along fibro-adipogenic lineages while inhibiting myogenesis. These results have implications for a possible role of muscle SP cells in fibrosis and fat deposition in muscular dystrophy. In addition, our studies provide a useful in vitro system to analyze SP cell biology in both normal and pathological conditions.

  15. A methodology for distinguishing divergent cell fates within a common progenitor population: adenoma- and neuroendocrine-like cells are confounders of rat ileal epithelial cell (IEC-18 culture

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    Paxton Jessica B

    2005-01-01

    Full Text Available Abstract Background IEC-18 cells are a non-transformed, immortal cell line derived from juvenile rat ileal crypt cells. They may have experimental advantages over tumor-derived gastrointestinal lineages, including preservation of phenotype, normal endocrine responses and retention of differentiation potential. However, their proclivity for spontaneous differentiation / transformation may be stereotypical and could represent a more profound experimental confounder than previously realized. We hypothesized that IEC-18 cells spontaneously diverge towards a uniform mixture of epigenetic fates, with corresponding phenotypes, rather than persist as a single progenitor lineage. Results IEC-18 cells were cultured for 72 hours in serum free media (SFM, with and without various insulin-like growth factor agonists to differentially boost the basal rate of proliferation. A strategy was employed to identify constitutive genes as markers of divergent fates through gene array analysis by cross-referencing fold-change trends for individual genes against crypt cell abundance in each treatment. We then confirmed the cell-specific phenotype by immunolocalization of proteins corresponding to those genes. The majority of IEC-18 cells in SFM alone had a loss in expression of the adenomatous polyposis coli (APC gene at the mRNA and protein levels, consistent with adenoma-like transformation. In addition, a small subset of cells expressed the serotonin receptor 2A gene and had neuroendocrine-like morphology. Conclusions IEC-18 cells commonly undergo a change in cell fate prior to reaching confluence. The most common fate switch that we were able to detect correlates with a down regulation of the APC gene and transformation into an adenoma-like phenotype.

  16. Melatonin and Vitamin D Interfere with the Adipogenic Fate of Adipose-Derived Stem Cells.

    Science.gov (United States)

    Basoli, Valentina; Santaniello, Sara; Cruciani, Sara; Ginesu, Giorgio Carlo; Cossu, Maria Laura; Delitala, Alessandro Palmerio; Serra, Pier Andrea; Ventura, Carlo; Maioli, Margherita

    2017-05-05

    Adipose-derived stem cells (ADSCs) represent one of the cellular populations resident in adipose tissue. They can be recruited under certain stimuli and committed to become preadipocytes, and then mature adipocytes. Controlling stem cell differentiation towards the adipogenic phenotype could have a great impact on future drug development aimed at counteracting fat depots. Stem cell commitment can be influenced by different molecules, such as melatonin, which we have previously shown to be an osteogenic inducer. Here, we aimed at evaluating the effects elicited by melatonin, even in the presence of vitamin D, on ADSC adipogenesis assessed in a specific medium. The transcription of specific adipogenesis orchestrating genes, such as aP2, peroxisome proliferator-activated receptor γ (PPAR-γ), and that of adipocyte-specific genes, including lipoprotein lipase (LPL) and acyl-CoA thioesterase 2 (ACOT2), was significantly inhibited in cells that had been treated in the presence of melatonin and vitamin D, alone or in combination. Protein content and lipid accumulation confirmed a reduction in adipogenesis in ADSCs that had been grown in adipogenic conditions, but in the presence of melatonin and/or vitamin D. Our findings indicate the role of melatonin and vitamin D in deciding stem cell fate, and disclose novel therapeutic approaches against fat depots.

  17. Fss/Tbx6 is required for central dermomyotome cell fate in zebrafish

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    Stefanie Elisabeth Windner

    2012-06-01

    The dermomyotome is a pool of progenitor cells on the surface of the myotome. In zebrafish, dermomyotome precursors (anterior border cells, ABCs can be first identified in the anterior portion of recently formed somites. They must be prevented from undergoing terminal differentiation during segmentation, even while mesodermal cells around them respond to signaling cues and differentiate. T-box containing transcription factors regulate many aspects of mesoderm fate including segmentation and somite patterning. The fused somites (fss gene is the zebrafish ortholog of tbx6. We demonstrate that in addition to its requirement for segmentation, fss/tbx6 is also required for the specification of ABCs and subsequently the central dermomyotome. The absence of Tbx6-dependent central dermomyotome cells in fss/tbx6 mutants is spatially coincident with a patterning defect in the myotome. Using transgenic fish with a heat-shock inducible tbx6 gene in the fss/tbx6 mutant background, we further demonstrate that ubiquitous fss/tbx6 expression has spatially distinct effects on recovery of the dermomyotome and segment boundaries, suggesting that the mechanism of Fss/Tbx6 action is distinct with respect to dermomyotome development and segmentation. We propose that Fss/Tbx6 is required for preventing myogenic differentiation of central dermomyotome precursors before and after segmentation and that central dermomyotome cells represent a genetically and functionally distinct subpopulation within the zebrafish dermomyotome.

  18. Dentin Sialophosphoprotein: A Regulatory Protein for Dental Pulp Stem Cell Identity and Fate

    Science.gov (United States)

    Guo, Shiliang; Lim, Dandrich; Dong, Zhihong; Saunders, Thomas L.; Ma, Peter X.; Marcelo, Cynthia L.

    2014-01-01

    The dentin sialophosphoprotein (dspp) transcript is expressed during tooth development as a DSPP precursor protein, which then undergoes cleavage to form mature dentin sialoprotein (DSP) and phosphophoryn (PP) proteins. Previous studies using DSPP-knockout (KO) mice have reported that these animals have hypomineralized teeth, thin dentin, and a large dental pulp chamber, similar to those from patients with dentinogenesis imperfecta III. However, there is no information about factors that regulate dental pulp stem cell lineage fate, a critical early event in the odontoblast-dentin mineralization scheme. To reveal the role of DSPP in odontoblast lineage differentiation during tooth development, we systematically examined teeth from wild-type (wt) and DSPP-KO C57BL/6 mice between the ages of postnatal day 1 and 3 months. We found developmental abnormalities not previously reported, such as circular dentin formation within dental pulp cells and altered odontoblast differentiation in DSPP-KO mice, even as early as 1 day after birth. Surprisingly, we also identified chondrocyte-like cells in the dental pulp from KO-mice teeth. Thus, these studies that compare wt and DSPP-KO mice suggest that the expression of DSPP precursor protein is required for normal odontoblast lineage differentiation and that the absence of DSPP allows dental pulp cells to differentiate into chondrocyte-like cells, which could negatively impact pulpal wound healing and tissue regeneration. PMID:25027178

  19. Dentin sialophosphoprotein: a regulatory protein for dental pulp stem cell identity and fate.

    Science.gov (United States)

    Guo, Shiliang; Lim, Dandrich; Dong, Zhihong; Saunders, Thomas L; Ma, Peter X; Marcelo, Cynthia L; Ritchie, Helena H

    2014-12-01

    The dentin sialophosphoprotein (dspp) transcript is expressed during tooth development as a DSPP precursor protein, which then undergoes cleavage to form mature dentin sialoprotein (DSP) and phosphophoryn (PP) proteins. Previous studies using DSPP-knockout (KO) mice have reported that these animals have hypomineralized teeth, thin dentin, and a large dental pulp chamber, similar to those from patients with dentinogenesis imperfecta III. However, there is no information about factors that regulate dental pulp stem cell lineage fate, a critical early event in the odontoblast-dentin mineralization scheme. To reveal the role of DSPP in odontoblast lineage differentiation during tooth development, we systematically examined teeth from wild-type (wt) and DSPP-KO C57BL/6 mice between the ages of postnatal day 1 and 3 months. We found developmental abnormalities not previously reported, such as circular dentin formation within dental pulp cells and altered odontoblast differentiation in DSPP-KO mice, even as early as 1 day after birth. Surprisingly, we also identified chondrocyte-like cells in the dental pulp from KO-mice teeth. Thus, these studies that compare wt and DSPP-KO mice suggest that the expression of DSPP precursor protein is required for normal odontoblast lineage differentiation and that the absence of DSPP allows dental pulp cells to differentiate into chondrocyte-like cells, which could negatively impact pulpal wound healing and tissue regeneration.

  20. The selector gene Pax7 dictates alternate pituitary cell fates through its pioneer action on chromatin remodeling

    NARCIS (Netherlands)

    Budry, L.; Balsalobre, A.; Gauthier, Y.; Khetchoumian, K.; L'Honore, A.; Vallette-Kasic, S.; Brue, T; Figarella-Branger, D.; Meij, B.P.|info:eu-repo/dai/nl/164045805; Drouin, J.

    2012-01-01

    Genes Dev. 2012 Oct 15;26(20):2299-310. doi: 10.1101/gad.200436.112. The selector gene Pax7 dictates alternate pituitary cell fates through its pioneer action on chromatin remodeling. Budry L, Balsalobre A, Gauthier Y, Khetchoumian K, L'honoré A, Vallette S, Brue T, Figarella-Branger D, Meij B,

  1. It's all in your mind: determining germ cell fate by neuronal IRE-1 in C. elegans.

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    Mor Levi-Ferber

    2014-10-01

    Full Text Available The C. elegans germline is pluripotent and mitotic, similar to self-renewing mammalian tissues. Apoptosis is triggered as part of the normal oogenesis program, and is increased in response to various stresses. Here, we examined the effect of endoplasmic reticulum (ER stress on apoptosis in the C. elegans germline. We demonstrate that pharmacological or genetic induction of ER stress enhances germline apoptosis. This process is mediated by the ER stress response sensor IRE-1, but is independent of its canonical downstream target XBP-1. We further demonstrate that ire-1-dependent apoptosis in the germline requires both CEP-1/p53 and the same canonical apoptotic genes as DNA damage-induced germline apoptosis. Strikingly, we find that activation of ire-1, specifically in the ASI neurons, but not in germ cells, is sufficient to induce apoptosis in the germline. This implies that ER stress related germline apoptosis can be determined at the organism level, and is a result of active IRE-1 signaling in neurons. Altogether, our findings uncover ire-1 as a novel cell non-autonomous regulator of germ cell apoptosis, linking ER homeostasis in sensory neurons and germ cell fate.

  2. Antigen availability determines CD8⁺ T cell-dendritic cell interaction kinetics and memory fate decisions.

    Science.gov (United States)

    Henrickson, Sarah E; Perro, Mario; Loughhead, Scott M; Senman, Balimkiz; Stutte, Susanne; Quigley, Michael; Alexe, Gabriela; Iannacone, Matteo; Flynn, Michael P; Omid, Shaida; Jesneck, Jonathan L; Imam, Sabrina; Mempel, Thorsten R; Mazo, Irina B; Haining, W Nicholas; von Andrian, Ulrich H

    2013-09-19

    T cells are activated by antigen (Ag)-bearing dendritic cells (DCs) in lymph nodes in three phases. The duration of the initial phase of transient, serial DC-T cell interactions is inversely correlated with Ag dose. The second phase, characterized by stable DC-T cell contacts, is believed to be necessary for full-fledged T cell activation. Here we have shown that this is not the case. CD8⁺ T cells interacting with DCs presenting low-dose, short-lived Ag did not transition to phase 2, whereas higher Ag dose yielded phase 2 transition. Both antigenic constellations promoted T cell proliferation and effector differentiation but yielded different transcriptome signatures at 12 hr and 24 hr. T cells that experienced phase 2 developed long-lived memory, whereas conditions without stable contacts yielded immunological amnesia. Thus, T cells make fate decisions within hours after Ag exposure, resulting in long-term memory or abortive effector responses, correlating with T cell-DCs interaction kinetics. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Transcriptional regulation of lineage commitment--a stochastic model of cell fate decisions.

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    Jose Teles

    Full Text Available Molecular mechanisms employed by individual multipotent cells at the point of lineage commitment remain largely uncharacterized. Current paradigms span from instructive to noise-driven mechanisms. Of considerable interest is also whether commitment involves a limited set of genes or the entire transcriptional program, and to what extent gene expression configures multiple trajectories into commitment. Importantly, the transient nature of the commitment transition confounds the experimental capture of committing cells. We develop a computational framework that simulates stochastic commitment events, and affords mechanistic exploration of the fate transition. We use a combined modeling approach guided by gene expression classifier methods that infers a time-series of stochastic commitment events from experimental growth characteristics and gene expression profiling of individual hematopoietic cells captured immediately before and after commitment. We define putative regulators of commitment and probabilistic rules of transition through machine learning methods, and employ clustering and correlation analyses to interrogate gene regulatory interactions in multipotent cells. Against this background, we develop a Monte Carlo time-series stochastic model of transcription where the parameters governing promoter status, mRNA production and mRNA decay in multipotent cells are fitted to experimental static gene expression distributions. Monte Carlo time is converted to physical time using cell culture kinetic data. Probability of commitment in time is a function of gene expression as defined by a logistic regression model obtained from experimental single-cell expression data. Our approach should be applicable to similar differentiating systems where single cell data is available. Within our system, we identify robust model solutions for the multipotent population within physiologically reasonable values and explore model predictions with regard to

  4. The fate of radiation induced giant-nucleated cells of human skin fibroblasts

    Science.gov (United States)

    Almahwasi, A. A.; Jeynes, J. C.; Bradley, D. A.; Regan, P. H.

    2017-11-01

    Radiation-induced giant-nucleated cells (GCs) have been observed to occur within survivors of irradiated cancerous and within healthy cells, both in vivo and in vitro. The expression of such morphological alterations is associated with genomic instability. This study was designed to investigate the fate of GCs induced in a normal human fibroblast cell line (AG1522) after exposure to 0.2, 1 or 2 Gy of X-ray or proton irradiation. The total of 79 individual AG1522 GCs present at 7, 14 or 21 days after each dose point were analysed from fluorescence microscopy images captured over approximately 120 h. The GCs were identified at the beginning of the observation period for each time point post-irradiation and the area of the cell nucleus was measured (μm2) using a cell-recognition MATLAB code. The results demonstrate that the majority of GCs had undergone a prolonged mitotic arrest, which might be an indication of the survival strategy. The live cell microscopy confirms that a giant-nucleated cell formed 14 days after exposure to 0.2 Gy of proton irradiation was divided into two asymmetrical normal-sized cells. These results suggest that a small fraction of GCs can proliferate and form progeny. Some of GCs had disappeared from the microscopy fields. The rate of their loss was decreased as the dose increased but there remains the potential for them to have progeny that could continue to proliferate, ultimately contributing to development of cancer risk. This important method to access delayed effects in normal tissues could act as a potential radioprotective assay for a dose-limiting parameter when applying radiotherapy. These results might have important implications in evaluating risk estimates for patients during radiation therapy treatment.

  5. The Fate of the Adipose-Derived Stromal Cells during Angiogenesis and Adipogenesis after Cell-Assisted Lipotransfer.

    Science.gov (United States)

    Hong, Ki Yong; Yim, Sangjun; Kim, Hyun Jung; Jin, Ung Sik; Lim, SooA; Eo, SuRak; Chang, Hak; Minn, Kyung Won

    2018-02-01

    Cell-assisted lipotransfer is a process in which fat grafting is supplemented with autologous adipose-derived stromal cells. Since the efficacy of the technique was demonstrated, studies have focused on the mechanism by which cell-assisted lipotransfer enhances the rate of graft survival. However, the microenvironmental changes in donor and recipient tissue associated with cell-assisted lipotransfer remain unclear. The authors introduced an animal model of cell-assisted lipotransfer using two different transgenic reporter mice. Donor fat from green fluorescent protein-expressing C57BL/6J mice and donor adipose-derived stromal cells from DsRed-expressing C57BL/6J mice were co-transplanted into recipient C57BL/6J mice. During adipose remodeling after cell-assisted lipotransfer, the fate of each donor adipocyte and donor adipose-derived stromal cell was traced using immunofluorescent staining with the whole-mount method. Adipose-derived stromal cell supplementation altered inflammation and promoted angiogenesis and subsequent revascularization in recipient tissue. Tracing at postoperative week 4 revealed that surviving donor adipose-derived stromal cells participated in angiogenesis by differentiating into endothelial cells. Moreover, newly differentiated fat from donor adipose-derived stromal cells and recipient tissue integrated with surviving donor fat, leading to improved retention of the graft. Adipose-derived stromal cell supplementation resulted in a quantitative difference in angiogenesis and adipogenesis during adipose remodeling according to the concentration of adipose-derived stromal cells. The authors characterized the dynamic changes occurring in donor adipose-derived stromal cells and fat and recipient tissue by tracing these cellular components following cell-assisted lipotransfer. The authors' findings highlight the therapeutic value of cell-assisted lipotransfer in tissue transplantation.

  6. Gene regulatory networks in neural cell fate acquisition from genome-wide chromatin association of Geminin and Zic1

    Science.gov (United States)

    Sankar, Savita; Yellajoshyula, Dhananjay; Zhang, Bo; Teets, Bryan; Rockweiler, Nicole; Kroll, Kristen L.

    2016-01-01

    Neural cell fate acquisition is mediated by transcription factors expressed in nascent neuroectoderm, including Geminin and members of the Zic transcription factor family. However, regulatory networks through which this occurs are not well defined. Here, we identified Geminin-associated chromatin locations in embryonic stem cells and Geminin- and Zic1-associated locations during neural fate acquisition at a genome-wide level. We determined how Geminin deficiency affected histone acetylation at gene promoters during this process. We integrated these data to demonstrate that Geminin associates with and promotes histone acetylation at neurodevelopmental genes, while Geminin and Zic1 bind a shared gene subset. Geminin- and Zic1-associated genes exhibit embryonic nervous system-enriched expression and encode other regulators of neural development. Both Geminin and Zic1-associated peaks are enriched for Zic1 consensus binding motifs, while Zic1-bound peaks are also enriched for Sox3 motifs, suggesting co-regulatory potential. Accordingly, we found that Geminin and Zic1 could cooperatively activate the expression of several shared targets encoding transcription factors that control neurogenesis, neural plate patterning, and neuronal differentiation. We used these data to construct gene regulatory networks underlying neural fate acquisition. Establishment of this molecular program in nascent neuroectoderm directly links early neural cell fate acquisition with regulatory control of later neurodevelopment. PMID:27881878

  7. Determining the fate of fluorescent quantum dots on surface of engineered budding S. cerevisiae cell molecular landscape.

    Science.gov (United States)

    Chouhan, Raghuraj S; Qureshi, Anjum; Niazi, Javed H

    2015-07-15

    In this study, we surface engineered living S. cerevisiae cells by decorating quantum dots (QDs) and traced the fate of QDs on molecular landscape of single mother cell through several generation times (progeny cells). The fate of QDs on cell-surface was tracked through the cellular division events using confocal microscopy and fluorescence emission profiles. The extent of cell-surface QDs distribution among the offspring was determined as the mother cell divides into daughter cells. Fluorescence emission from QDs on progeny cells was persistent through the second-generation time (~240min) until all of the progeny cells lost their cell-bound QDs during the third generation time (~360min). The surface engineered yeast cells were unaffected by the QDs present on their molecular landscapes and retained their normal cellular growth, architecture and metabolic activities as confirmed by their viability, scanning electron microscopy (SEM) examinations and cytotoxicity tests, respectively. Our results demonstrated that QDs on mother cell landscape tend to distribute among its progeny cells that accompanied with concomitant reduction in QDs' fluorescence, which can be quantified. We suggest that surface engineered cells with QDs will enable investigating the cellular behavior and monitoring cell growth patterns as nanobiosensors for screening of drugs/chemicals at single cell level with fewer side effects. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Mechanobiology of mesenchymal stem cells: Perspective into mechanical induction of MSC fate.

    Science.gov (United States)

    Hao, Jin; Zhang, Yueling; Jing, Dian; Shen, Yu; Tang, Ge; Huang, Shishu; Zhao, Zhihe

    2015-07-01

    Bone marrow-derived mesenchymal stem and stromal cells (MSCs) are promising candidates for cell-based therapies in diverse conditions including tissue engineering. Advancement of these therapies relies on the ability to direct MSCs toward specific cell phenotypes. Despite identification of applied forces that affect self-maintenance, proliferation, and differentiation of MSCs, mechanisms underlying the integration of mechanically induced signaling cascades and interpretation of mechanical signals by MSCs remain elusive. During the past decade, many researchers have demonstrated that external applied forces can activate osteogenic signaling pathways in MSCs, including Wnt, Ror2, and Runx2. Besides, recent advances have highlighted the critical role of internal forces due to cell-matrix interaction in MSC function. These internal forces can be achieved by the materials that cells reside in through its mechanical properties, such as rigidity, topography, degradability, and substrate patterning. MSCs can generate contractile forces to sense these mechanical properties and thereby perceive mechanical information that directs broad aspects of MSC functions, including lineage commitment. Although many signaling pathways have been elucidated in material-induced lineage specification of MSCs, discovering the mechanisms by which MSCs respond to such cell-generated forces is still challenging because of the highly intricate signaling milieu present in MSC environment. However, bioengineers are bridging this gap by developing platforms to control mechanical cues with improved throughput and precision, thereby enabling further investigation of mechanically induced MSC functions. In this review, we discuss the most recent advances that how applied forces and cell-generated forces may be engineered to determine MSC fate, and overview a subset of the operative signal transduction mechanisms and experimental platforms that have emerged in MSC mechanobiology research. Our main goal

  9. Comparative Analysis of the Cell Fates of Induced Schwann Cells from Subcutaneous Fat Tissue and Naïve Schwann Cells in the Sciatic Nerve Injury Model

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    Mingzi Zhang

    2017-01-01

    Full Text Available Purpose. The fate and function of the induced Schwann cells (iSCs like cells from adipose tissue have not been critically evaluated in vivo after transplantation. The objective of this study is to compare the fate of iSCs with naïve SCs (nSCs after transplantation into the lesion sites of sciatic nerve, respectively. Methods. Adipose-derived stem cells from eGFP-expressing transgenic rat’s subcutaneous fat were induced to iSCs in vitro. iSCs were injected to the sciatic nerve lesion area after crush injury and the cells fate was comparatively analyzed with that of nSCs from the same rat. Results. At 12 weeks after transplantation, nSCs were detected only in the restricted area of cell transplantation site but iSCs were widely distributed all over the sciatic nerve. Based on double fluorescence observations, both iSCs and naïve ones were colocalized with P0-expressing myelin sheath, outbound by laminin-expressing basal membrane, and terminated at contactin-associated protein-expressing doublets. However, some of iSCs were also differentiated to the fibrocyte/fibroblast-like cells. In the histological analysis of repaired sciatic nerves, axon density was higher in iSC-received group than in the nSCs group and normal sciatic nerve. Conclusion. iSCs induced from subcutaneous fat tissues have higher engraftment and migration capacity than nSCs.

  10. Quantifying cell fate decisions for differentiation and reprogramming of a human stem cell network: landscape and biological paths.

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    Chunhe Li

    Full Text Available Cellular reprogramming has been recently intensively studied experimentally. We developed a global potential landscape and kinetic path framework to explore a human stem cell developmental network composed of 52 genes. We uncovered the underlying landscape for the stem cell network with two basins of attractions representing stem and differentiated cell states, quantified and exhibited the high dimensional biological paths for the differentiation and reprogramming process, connecting the stem cell state and differentiated cell state. Both the landscape and non-equilibrium curl flux determine the dynamics of cell differentiation jointly. Flux leads the kinetic paths to be deviated from the steepest descent gradient path, and the corresponding differentiation and reprogramming paths are irreversible. Quantification of paths allows us to find out how the differentiation and reprogramming occur and which important states they go through. We show the developmental process proceeds as moving from the stem cell basin of attraction to the differentiation basin of attraction. The landscape topography characterized by the barrier heights and transition rates quantitatively determine the global stability and kinetic speed of cell fate decision process for development. Through the global sensitivity analysis, we provided some specific predictions for the effects of key genes and regulation connections on the cellular differentiation or reprogramming process. Key links from sensitivity analysis and biological paths can be used to guide the differentiation designs or reprogramming tactics.

  11. Involvement of crosstalk between Oct4 and Meis1a in neural cell fate decision.

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    Takeyuki Yamada

    Full Text Available Oct4 plays a critical role both in maintaining pluripotency and the cell fate decision of embryonic stem (ES cells. Nonetheless, in the determination of the neuroectoderm (NE from ES cells, the detailed regulation mechanism of the Oct4 gene expression is poorly understood. Here, we report that crosstalk between Oct4 and Meis1a, a Pbx-related homeobox protein, is required for neural differentiation of mouse P19 embryonic carcinoma (EC cells induced by retinoic acid (RA. During neural differentiation, Oct4 expression was transiently enhanced during 6-12 h of RA addition and subsequently disappeared within 48 h. Coinciding with up-regulation of Oct4 expression, the induction of Meis1a expression was initiated and reached a plateau at 48 h, suggesting that transiently induced Oct4 activates Meis1a expression and the up-regulated Meis1a then suppresses Oct4 expression. Chromatin immunoprecipitation (ChIP and luciferase reporter analysis showed that Oct4 enhanced Meis1a expression via direct binding to the Meis1 promoter accompanying histone H3 acetylation and appearance of 5-hydoxymethylcytosine (5hmC, while Meis1a suppressed Oct4 expression via direct association with the Oct4 promoter together with histone deacetylase 1 (HDAC1. Furthermore, ectopic Meis1a expression promoted neural differentiation via formation of large neurospheres that expressed Nestin, GLAST, BLBP and Sox1 as neural stem cell (NSC/neural progenitor markers, whereas its down-regulation generated small neurospheres and repressed neural differentiation. Thus, these results imply that crosstalk between Oct4 and Meis1a on mutual gene expressions is essential for the determination of NE from EC cells.

  12. Modified mRNA directs the fate of heart progenitor cells and induces vascular regeneration after myocardial infarction

    Science.gov (United States)

    Zangi, Lior; Lui, Kathy O.; von Gise, Alexander; Ma, Qing; Ebina, Wataru; Ptaszek, Leon M.; Später, Daniela; Xu, Huansheng; Tabebordbar, Mohammadsharif; Gorbatov, Rostic; Sena, Brena; Nahrendorf, Matthias; Briscoe, David M.; Li, Ronald A.; Wagers, Amy J.; Rossi, Derrick J.; Pu, William T.; Chien, Kenneth R.

    2014-01-01

    In a cell-free approach to regenerative therapeutics, transient application of paracrine factors in vivo could be used to alter the behavior and fate of progenitor cells to achieve sustained clinical benefits. Here we show that intramyocardial injection of synthetic modified RNA (modRNA) encoding human vascular endothelial growth factor-A (VEGF-A) resulted in the expansion and directed differentiation of endogenous heart progenitors in a murine myocardial infarction model. VEGF-A modRNA markedly improved heart function and enhanced long-term survival of recipients. This improvement was in part due to mobilization of epicardial progenitor cells and redirection of their differentiation toward cardiovascular cell types. Direct in vivo comparison with DNA vectors, and temporal control with VEGF inhibitors, documented the markedly increased efficacy of pulse-like delivery of VEGF-A. Our results suggest that modRNA is a versatile approach for expressing paracrine factors as cell fate switches to control progenitor cell fate and thereby enhance long term organ repair. PMID:24013197

  13. Data on the fate of MACS® MicroBeads intramyocardially co-injected with stem cell products

    Directory of Open Access Journals (Sweden)

    Paula Müller

    2017-08-01

    Full Text Available The data presented in this article are related to the research article “Intramyocardial Fate and Effect of Iron Nanoparticles co-injected with MACS® purified Stem Cell Products” (Müller et al., 2017 [1]. This article complements the cellular localization of superparamagnetic iron dextran particles (MACS® MicroBeads used for magnetic activated cell sorting (MACS®. Data evaluate the time-dependent detachment of these nanoparticles from CD133+ haematopoietic stem cells (HSCs and CD271+ mesenchymal stem cells (MSCs. Furthermore, the influence of these stem cells as well as of nanoparticles on cardiac remodeling processes after myocardial infarction (MI was investigated.

  14. Leptin changes differentiation fate and induces senescence in chondrogenic progenitor cells.

    Science.gov (United States)

    Zhao, X; Dong, Y; Zhang, J; Li, D; Hu, G; Yao, J; Li, Y; Huang, P; Zhang, M; Zhang, J; Huang, Z; Zhang, Y; Miao, Y; Xu, Q; Li, H

    2016-04-14

    Body weight is a component of the mechanical theory of OA (osteoarthritis) pathogenesis. Obesity was also found to be a risk factor for digital OA involving non-weight-bearing joints, which suggested that metabolism influences the occurrence and progression of OA. The metabolic origin of OA has been partially attributed to the involvement of adipokines, such as leptin, the levels of which are significantly and positively correlated with cartilage degeneration in OA patients. However, the mechanisms by which leptin-induced cartilage degeneration occurs are poorly understood. The discovery of chondrogenic progenitor cells (CPCs) opened up new opportunities for investigation. Investigating the effects of leptin on differentiation and proliferation in CPCs would increase our understanding of the roles played by leptin in the aetiology and development of OA. Here, CPCs were harvested using single-cell sorting from rat cartilage tissues to obtain mesenchymal stem-like cells, which possess clonogenicity, proliferation and stemness. High doses of leptin decreased the ability of the CPCs to migrate, inhibited their chondrogenic potential and increased their osteogenic potential, suggesting that leptin changes differentiation fates in CPCs. High doses of leptin induced cell cycle arrest and senescence in CPCs by activating the p53/p21 pathway and inhibiting the Sirt1 pathway. Inhibiting the Sirt1 pathway accelerated cartilage senescence in knockout (KO) mice. Activating the leptin pathway induced higher Ob-Rb expression and was significantly correlated with cartilage degeneration (lower levels of Coll-2) and tissue senescence (higher levels of p53/p21 and lower levels of Sirt1) in OA patients, suggesting that leptin-induced CPCs senescence contributes to the development of OA. Taken together, our results reveal new links between obesity and cartilage damage that are induced by leptin-mediated effects on cell behaviour and senescence.

  15. Fez family transcription factors: control of neurogenesis and cell fate in the developing mammalian nervous system

    Science.gov (United States)

    Eckler, Matthew J.; Chen, Bin

    2017-01-01

    Fezf1 and Fezf2 are highly conserved transcription factors that were first identified by their specific expression in the anterior neuroepithelium of Xenopus and zebrafish embryos. These proteins share an N-terminal domain with homology to the canonical engrailed repressor motif and a C-terminal DNA binding domain containing six C2H2 zinc-finger repeats. Over a decade of study indicates that the Fez proteins play critical roles during nervous system development in species as diverse as fruit flies and mice. Herein we discuss recent progress in understanding the functions of Fezf1 and Fezf2 in neurogenesis and cell fate specification during mammalian nervous system development. Going forward we believe that efforts should focus on understanding how expression of these factors is precisely regulated, and on identifying target DNA sequences and interacting partners. Such knowledge may reveal the mechanisms by which Fezf1 and Fezf2 accomplish both independent and redundant functions across diverse tissue and cell types. PMID:24913420

  16. Fez family transcription factors: controlling neurogenesis and cell fate in the developing mammalian nervous system.

    Science.gov (United States)

    Eckler, Matthew J; Chen, Bin

    2014-08-01

    Fezf1 and Fezf2 are highly conserved transcription factors that were first identified by their specific expression in the anterior neuroepithelium of Xenopus and zebrafish embryos. These proteins share an N-terminal domain with homology to the canonical engrailed repressor motif and a C-terminal DNA binding domain containing six C2H2 zinc-finger repeats. Over a decade of study indicates that the Fez proteins play critical roles during nervous system development in species as diverse as fruit flies and mice. Herein we discuss recent progress in understanding the functions of Fezf1 and Fezf2 in neurogenesis and cell fate specification during mammalian nervous system development. Going forward we believe that efforts should focus on understanding how expression of these factors is precisely regulated, and on identifying target DNA sequences and interacting partners. Such knowledge may reveal the mechanisms by which Fezf1 and Fezf2 accomplish both independent and redundant functions across diverse tissue and cell types. © 2014 WILEY Periodicals, Inc.

  17. YUCCA-mediated auxin biogenesis is required for cell fate transition occurring during de novo root organogenesis in Arabidopsis.

    Science.gov (United States)

    Chen, Lyuqin; Tong, Jianhua; Xiao, Langtao; Ruan, Ying; Liu, Jingchun; Zeng, Minhuan; Huang, Hai; Wang, Jia-Wei; Xu, Lin

    2016-07-01

    Many plant organs have the ability to regenerate a new plant after detachment or wounding via de novo organogenesis. During de novo root organogenesis from Arabidopsis thaliana leaf explants, endogenic auxin is essential for the fate transition of regeneration-competent cells to become root founder cells via activation of WUSCHEL-RELATED HOMEOBOX 11 (WOX11). However, the molecular events from leaf explant detachment to auxin-mediated cell fate transition are poorly understood. In this study, we used an assay to determine the concentration of indole-3-acetic acid (IAA) to provide direct evidence that auxin is produced after leaf explant detachment, a process that involves YUCCA (YUC)-mediated auxin biogenesis. Inhibition of YUC prevents expression of WOX11 and fate transition of competent cells, resulting in the blocking of rooting. Further analysis showed that YUC1 and YUC4 act quickly (within 4 hours) in response to wounding after detachment in both light and dark conditions and promote auxin biogenesis in both mesophyll and competent cells, whereas YUC5, YUC8, and YUC9 primarily respond in dark conditions. In addition, YUC2 and YUC6 contribute to rooting by providing a basal auxin level in the leaf. Overall, our study indicates that YUC genes exhibit a division of labour during de novo root organogenesis from leaf explants in response to multiple signals. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  18. A Pitx2-MicroRNA Pathway Modulates Cell Proliferation in Myoblasts and Skeletal-Muscle Satellite Cells and Promotes Their Commitment to a Myogenic Cell Fate

    Science.gov (United States)

    Lozano-Velasco, Estefanía; Vallejo, Daniel; Esteban, Francisco J.; Doherty, Chris; Hernández-Torres, Francisco; Franco, Diego

    2015-01-01

    The acquisition of a proliferating-cell status from a quiescent state as well as the shift between proliferation and differentiation are key developmental steps in skeletal-muscle stem cells (satellite cells) to provide proper muscle regeneration. However, how satellite cell proliferation is regulated is not fully understood. Here, we report that the c-isoform of the transcription factor Pitx2 increases cell proliferation in myoblasts by downregulating microRNA 15b (miR-15b), miR-23b, miR-106b, and miR-503. This Pitx2c-microRNA (miRNA) pathway also regulates cell proliferation in early-activated satellite cells, enhancing Myf5+ satellite cells and thereby promoting their commitment to a myogenic cell fate. This study reveals unknown functions of several miRNAs in myoblast and satellite cell behavior and thus may have future applications in regenerative medicine. PMID:26055324

  19. Termination factor Rho: From the control of pervasive transcription to cell fate determination in Bacillus subtilis

    Science.gov (United States)

    Nicolas, Pierre; Repoila, Francis; Bardowski, Jacek; Aymerich, Stéphane

    2017-01-01

    In eukaryotes, RNA species originating from pervasive transcription are regulators of various cellular processes, from the expression of individual genes to the control of cellular development and oncogenesis. In prokaryotes, the function of pervasive transcription and its output on cell physiology is still unknown. Most bacteria possess termination factor Rho, which represses pervasive, mostly antisense, transcription. Here, we investigate the biological significance of Rho-controlled transcription in the Gram-positive model bacterium Bacillus subtilis. Rho inactivation strongly affected gene expression in B. subtilis, as assessed by transcriptome and proteome analysis of a rho–null mutant during exponential growth in rich medium. Subsequent physiological analyses demonstrated that a considerable part of Rho-controlled transcription is connected to balanced regulation of three mutually exclusive differentiation programs: cell motility, biofilm formation, and sporulation. In the absence of Rho, several up-regulated sense and antisense transcripts affect key structural and regulatory elements of these differentiation programs, thereby suppressing motility and biofilm formation and stimulating sporulation. We dissected how Rho is involved in the activity of the cell fate decision-making network, centered on the master regulator Spo0A. We also revealed a novel regulatory mechanism of Spo0A activation through Rho-dependent intragenic transcription termination of the protein kinase kinB gene. Altogether, our findings indicate that distinct Rho-controlled transcripts are functional and constitute a previously unknown built-in module for the control of cell differentiation in B. subtilis. In a broader context, our results highlight the recruitment of the termination factor Rho, for which the conserved biological role is probably to repress pervasive transcription, in highly integrated, bacterium-specific, regulatory networks. PMID:28723971

  20. High incidence of non-random template strand segregation and asymmetric fate determination in dividing stem cells and their progeny.

    Directory of Open Access Journals (Sweden)

    Michael J Conboy

    2007-05-01

    Full Text Available Decades ago, the "immortal strand hypothesis" was proposed as a means by which stem cells might limit acquiring mutations that could give rise to cancer, while continuing to proliferate for the life of an organism. Originally based on observations in embryonic cells, and later studied in terms of stem cell self-renewal, this hypothesis has remained largely unaccepted because of few additional reports, the rarity of the cells displaying template strand segregation, and alternative interpretations of experiments involving single labels or different types of labels to follow template strands. Using sequential pulses of halogenated thymidine analogs (bromodeoxyuridine [BrdU], chlorodeoxyuridine [CldU], and iododeoxyuridine [IdU], and analyzing stem cell progeny during induced regeneration in vivo, we observed extraordinarily high frequencies of segregation of older and younger template strands during a period of proliferative expansion of muscle stem cells. Furthermore, template strand co-segregation was strongly associated with asymmetric cell divisions yielding daughters with divergent fates. Daughter cells inheriting the older templates retained the more immature phenotype, whereas daughters inheriting the newer templates acquired a more differentiated phenotype. These data provide compelling evidence of template strand co-segregation based on template age and associated with cell fate determination, suggest that template strand age is monitored during stem cell lineage progression, and raise important caveats for the interpretation of label-retaining cells.

  1. Following cell-fate in E. coli after infection by phage lambda.

    Science.gov (United States)

    Zeng, Lanying; Golding, Ido

    2011-10-14

    The system comprising bacteriophage (phage) lambda and the bacterium E. coli has long served as a paradigm for cell-fate determination. Following the simultaneous infection of the cell by a number of phages, one of two pathways is chosen: lytic (virulent) or lysogenic (dormant). We recently developed a method for fluorescently labeling individual phages, and were able to examine the post-infection decision in real-time under the microscope, at the level of individual phages and cells. Here, we describe the full procedure for performing the infection experiments described in our earlier work. This includes the creation of fluorescent phages, infection of the cells, imaging under the microscope and data analysis. The fluorescent phage is a "hybrid", co-expressing wild- type and YFP-fusion versions of the capsid gpD protein. A crude phage lysate is first obtained by inducing a lysogen of the gpD-EYFP (Enhanced Yellow Fluorescent Protein) phage, harboring a plasmid expressing wild type gpD. A series of purification steps are then performed, followed by DAPI-labeling and imaging under the microscope. This is done in order to verify the uniformity, DNA packaging efficiency, fluorescence signal and structural stability of the phage stock. The initial adsorption of phages to bacteria is performed on ice, then followed by a short incubation at 35°C to trigger viral DNA injection. The phage/bacteria mixture is then moved to the surface of a thin nutrient agar slab, covered with a coverslip and imaged under an epifluorescence microscope. The post-infection process is followed for 4 hr, at 10 min interval. Multiple stage positions are tracked such that ~100 cell infections can be traced in a single experiment. At each position and time point, images are acquired in the phase-contrast and red and green fluorescent channels. The phase-contrast image is used later for automated cell recognition while the fluorescent channels are used to characterize the infection outcome

  2. Neuronal Cell Fate Specification by the Convergence of Different Spatiotemporal Cues on a Common Terminal Selector Cascade.

    Directory of Open Access Journals (Sweden)

    Hugo Gabilondo

    2016-05-01

    Full Text Available Specification of the myriad of unique neuronal subtypes found in the nervous system depends upon spatiotemporal cues and terminal selector gene cascades, often acting in sequential combinatorial codes to determine final cell fate. However, a specific neuronal cell subtype can often be generated in different parts of the nervous system and at different stages, indicating that different spatiotemporal cues can converge on the same terminal selectors to thereby generate a similar cell fate. However, the regulatory mechanisms underlying such convergence are poorly understood. The Nplp1 neuropeptide neurons in the Drosophila ventral nerve cord can be subdivided into the thoracic-ventral Tv1 neurons and the dorsal-medial dAp neurons. The activation of Nplp1 in Tv1 and dAp neurons depends upon the same terminal selector cascade: col>ap/eya>dimm>Nplp1. However, Tv1 and dAp neurons are generated by different neural progenitors (neuroblasts with different spatiotemporal appearance. Here, we find that the same terminal selector cascade is triggered by Kr/pdm>grn in dAp neurons, but by Antp/hth/exd/lbe/cas in Tv1 neurons. Hence, two different spatiotemporal combinations can funnel into a common downstream terminal selector cascade to determine a highly related cell fate.

  3. Oct-3/4 regulates stem cell identity and cell fate decisions by modulating Wnt/β-catenin signalling

    Science.gov (United States)

    Abu-Remaileh, Monther; Gerson, Ariela; Farago, Marganit; Nathan, Gili; Alkalay, Irit; Zins Rousso, Sharon; Gur, Michal; Fainsod, Abraham; Bergman, Yehudit

    2010-01-01

    Although the transcriptional regulatory events triggered by Oct-3/4 are well documented, understanding the proteomic networks that mediate the diverse functions of this POU domain homeobox protein remains a major challenge. Here, we present genetic and biochemical studies that suggest an unexpected novel strategy for Oct-3/4-dependent regulation of embryogenesis and cell lineage determination. Our data suggest that Oct-3/4 specifically interacts with nuclear β-catenin and facilitates its proteasomal degradation, resulting in the maintenance of an undifferentiated, early embryonic phenotype both in Xenopus embryos and embryonic stem (ES) cells. Our data also show that Oct-3/4-mediated control of β-catenin stability has an important function in regulating ES cell motility. Down-regulation of Oct-3/4 increases β-catenin protein levels, enhancing Wnt signalling and initiating invasive cellular activity characteristic of epithelial-mesenchymal transition. Our data suggest a novel mode of regulation by which a delicate balance between β-catenin, Tcf3 and Oct-3/4 regulates maintenance of stem cell identity. Altering the balance between these proteins can direct cell fate decisions and differentiation. PMID:20736927

  4. Advanced imaging approaches for regenerative medicine: Emerging technologies for monitoring stem cell fate in vitro and in vivo.

    Science.gov (United States)

    Kupfer, Molly E; Ogle, Brenda M

    2015-10-01

    The future of regenerative medicine relies on our ability to control stem cell fate in order to produce functional tissues. Stem cells are the preferred cell source for tissue engineering endeavors and regenerative medicine therapies due to their high potency and capacity for expansion. However, their potency also makes them very difficult to control, as they are in a constant state of flux. Therefore, in order to advance research in regenerative medicine, it is necessary to be able to monitor cell state and phenotype both in vitro and in vivo. This review will detail the imaging technologies currently in use to monitor stem cell phenotype, migration, and differentiation. In addition to providing examples of the most recent work in this area, we will also discuss the future of imaging technologies for regenerative medicine, and how current imaging modalities might be utilized to image specific cell functionality in order to track stem cell fate. The research area of imaging stem cells is progressing toward identifying mature and differentiating cells not only by phenotypic markers, but also by visualizing cell function. Many of the cutting-edge modalities detailed in this review have the potential to be harnessed toward this goal. Copyright © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Modifications to glucocorticoid and progesterone receptors alter cell fate in breast cancer.

    Science.gov (United States)

    Leehy, Katherine A; Regan Anderson, Tarah M; Daniel, Andrea R; Lange, Carol A; Ostrander, Julie H

    2016-04-01

    Steroid hormone receptors (SRs) are heavily posttranslationally modified by the reversible addition of a variety of molecular moieties, including phosphorylation, acetylation, methylation, SUMOylation, and ubiquitination. These rapid and dynamic modifications may be combinatorial and interact (i.e. may be sequential, complement, or oppose each other), creating a vast array of uniquely modified receptor subspecies that allow for diverse receptor behaviors that enable highly sensitive and context-dependent hormone action. For example, in response to hormone or growth factor membrane-initiated signaling events, posttranslational modifications (PTMs) to SRs alter protein-protein interactions that govern the complex process of promoter or gene-set selection coupled to transcriptional repression or activation. Unique phosphorylation events allow SRs to associate or disassociate with specific cofactors that may include pioneer factors and other tethering partners, which specify the resulting transcriptome and ultimately change cell fate. The impact of PTMs on SR action is particularly profound in the context of breast tumorigenesis, in which frequent alterations in growth factor-initiated signaling pathways occur early and act as drivers of breast cancer progression toward endocrine resistance. In this article, with primary focus on breast cancer relevance, we review the mechanisms by which PTMs, including reversible phosphorylation events, regulate the closely related SRs, glucocorticoid receptor and progesterone receptor, allowing for precise biological responses to ever-changing hormonal stimuli. © 2016 Society for Endocrinology.

  6. Suspension culture of pluripotent stem cells: effect of shear on stem cell fate.

    Science.gov (United States)

    Keller, Kevin C; Rodrigues, Beatriz; zur Nieden, Nicole I

    2014-01-01

    Despite significant promise, the routine usage of suspension cell culture to manufacture stem cell-derived differentiated cells has progressed slowly. Suspension culture is an innovative way of either expanding or differentiating cells and sometimes both are combined into a single bioprocess. Its advantages over static 2D culturing include a homogeneous and controllable culture environment and producing a large quantity of cells in a fraction of time. This feature makes suspension cell culture ideal for use in stem cell research and eventually ideal in the large-scale production of differentiated cells for regenerative medicine. Because of their tremendous differentiation capacities and unlimited growth properties, pluripotent stem cells (PSCs) in particular are considered potential sources for future cell-replacement therapies. Currently, expansion of PSCs is accomplished in 2D, which only permits a limited amount of cell growth per culture flask before cells need to be passaged. However, before stem cells can be applied clinically, several aspects of their expansion, such as directed growth, but also differentiation, need to be better controlled. This review will summarize recent advantages in suspension culture of PSCs, while at the same time highlighting current challenges.

  7. Asymmetric cell division and its role in cell fate determination in the ...

    Indian Academy of Sciences (India)

    Supplementary figure 1. Light micrograph of an asymmetrically dividing T. indica cell at various time intervals. Progress over a 12 hr period, showing that the larger component does not undergo further division. (A) 0 h, cell division at an early stage. (B) 5 h, lower half of cell undergoing further division. (C) 12 h, differentiated ...

  8. Uptake and fate of surface modified silica nanoparticles in head and neck squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Besic Gyenge Emina

    2011-08-01

    Full Text Available Abstract Background Head and neck squamous cell carcinoma (HNSCC is currently the eighth leading cause of cancer death worldwide. The often severe side effects, functional impairments and unfavorable cosmetic outcome of conventional therapies for HNSCC have prompted the quest for novel treatment strategies, including the evaluation of nanotechnology to improve e.g. drug delivery and cancer imaging. Although silica nanoparticles hold great promise for biomedical applications, they have not yet been investigated in the context of HNSCC. In the present in-vitro study we thus analyzed the cytotoxicity, uptake and intracellular fate of 200-300 nm core-shell silica nanoparticles encapsulating fluorescent dye tris(bipyridineruthenium(II dichloride with hydroxyl-, aminopropyl- or PEGylated surface modifications (Ru@SiO2-OH, Ru@SiO2-NH2, Ru@SiO2-PEG in the human HNSCC cell line UMB-SCC 745. Results We found that at concentrations of 0.125 mg/ml, none of the nanoparticles used had a statistically significant effect on proliferation rates of UMB-SCC 745. Confocal and transmission electron microscopy showed an intracellular appearance of Ru@SiO2-OH and Ru@SiO2-NH2 within 30 min. They were internalized both as single nanoparticles (presumably via clathrin-coated pits or in clusters and always localized to cytoplasmic membrane-bounded vesicles. Immunocytochemical co-localization studies indicated that only a fraction of these nanoparticles were transferred to early endosomes, while the majority accumulated in large organelles. Ru@SiO2-OH and Ru@SiO2-NH2 nanoparticles had never been observed to traffic to the lysosomal compartment and were rather propagated at cell division. Intracellular persistence of Ru@SiO2-OH and Ru@SiO2-NH2 was thus traceable over 5 cell passages, but did not result in apparent changes in cell morphology and vitality. In contrast to Ru@SiO2-OH and Ru@SiO2-NH2 uptake of Ru@SiO2-PEG was minimal even after 24 h. Conclusions Our study is the

  9. A Gap Junction Protein, Inx2, Modulates Calcium Flux to Specify Border Cell Fate during Drosophila oogenesis.

    Directory of Open Access Journals (Sweden)

    Aresh Sahu

    2017-01-01

    Full Text Available Intercellular communication mediated by gap junction (GJ proteins is indispensable during embryogenesis, tissue regeneration and wound healing. Here we report functional analysis of a gap junction protein, Innexin 2 (Inx2, in cell type specification during Drosophila oogenesis. Our data reveal a novel involvement of Inx2 in the specification of Border Cells (BCs, a migratory cell type, whose identity is determined by the cell autonomous STAT activity. We show that Inx2 influences BC fate specification by modulating STAT activity via Domeless receptor endocytosis. Furthermore, detailed experimental analysis has uncovered that Inx2 also regulates a calcium flux that transmits across the follicle cells. We propose that Inx2 mediated calcium flux in the follicle cells stimulates endocytosis by altering Dynamin (Shibire distribution which is in turn critical for careful calibration of STAT activation and, thus for BC specification. Together our data provide unprecedented molecular insights into how gap junction proteins can regulate cell-type specification.

  10. A Gap Junction Protein, Inx2, Modulates Calcium Flux to Specify Border Cell Fate during Drosophila oogenesis.

    Science.gov (United States)

    Sahu, Aresh; Ghosh, Ritabrata; Deshpande, Girish; Prasad, Mohit

    2017-01-01

    Intercellular communication mediated by gap junction (GJ) proteins is indispensable during embryogenesis, tissue regeneration and wound healing. Here we report functional analysis of a gap junction protein, Innexin 2 (Inx2), in cell type specification during Drosophila oogenesis. Our data reveal a novel involvement of Inx2 in the specification of Border Cells (BCs), a migratory cell type, whose identity is determined by the cell autonomous STAT activity. We show that Inx2 influences BC fate specification by modulating STAT activity via Domeless receptor endocytosis. Furthermore, detailed experimental analysis has uncovered that Inx2 also regulates a calcium flux that transmits across the follicle cells. We propose that Inx2 mediated calcium flux in the follicle cells stimulates endocytosis by altering Dynamin (Shibire) distribution which is in turn critical for careful calibration of STAT activation and, thus for BC specification. Together our data provide unprecedented molecular insights into how gap junction proteins can regulate cell-type specification.

  11. Sequence of neuron origin and neocortical laminar fate: relation to cell cycle of origin in the developing murine cerebral wall

    Science.gov (United States)

    Takahashi, T.; Goto, T.; Miyama, S.; Nowakowski, R. S.; Caviness, V. S. Jr

    1999-01-01

    Neurons destined for each region of the neocortex are known to arise approximately in an "inside-to-outside" sequence from a pseudostratified ventricular epithelium (PVE). This sequence is initiated rostrolaterally and propagates caudomedially. Moreover, independently of location in the PVE, the neuronogenetic sequence in mouse is divisible into 11 cell cycles that occur over a 6 d period. Here we use a novel "birth hour" method that identifies small cohorts of neurons born during a single 2 hr period, i.e., 10-20% of a single cell cycle, which corresponds to approximately 1.5% of the 6 d neuronogenetic period. This method shows that neurons arising with the same cycle of the 11 cycle sequence in mouse have common laminar fates even if they arise from widely separated positions on the PVE (neurons of fields 1 and 40) and therefore arise at different embryonic times. Even at this high level of temporal resolution, simultaneously arising cells occupy more than one cortical layer, and there is substantial overlap in the distributions of cells arising with successive cycles. We demonstrate additionally that the laminar representation of cells arising with a given cycle is little if at all modified over the early postnatal interval of histogenetic cell death. We infer from these findings that cell cycle is a neuronogenetic counting mechanism and that this counting mechanism is integral to subsequent processes that determine cortical laminar fate.

  12. Laser-assisted cell printing: principle, physical parameters versus cell fate and perspectives in tissue engineering.

    Science.gov (United States)

    Guillemot, Fabien; Souquet, Agnès; Catros, Sylvain; Guillotin, Bertrand

    2010-04-01

    We describe the physical parameters involved in laser-assisted cell printing and present evidence that this technology is coming of age. Finally we discuss how this high-throughput, high-resolution technique may help in reproducing local cell microenvironments, and thereby create functional tissue-engineered 3D constructs.

  13. Hippo pathway effectors control cardiac progenitor cell fate by acting as dynamic sensors of substrate mechanics and nanostructure

    KAUST Repository

    Mosqueira, Diogo

    2014-03-25

    Stem cell responsiveness to extracellular matrix (ECM) composition and mechanical cues has been the subject of a number of investigations so far, yet the molecular mechanisms underlying stem cell mechano-biology still need full clarification. Here we demonstrate that the paralog proteins YAP and TAZ exert a crucial role in adult cardiac progenitor cell mechano-sensing and fate decision. Cardiac progenitors respond to dynamic modifications in substrate rigidity and nanopattern by promptly changing YAP/TAZ intracellular localization. We identify a novel activity of YAP and TAZ in the regulation of tubulogenesis in 3D environments and highlight a role for YAP/TAZ in cardiac progenitor proliferation and differentiation. Furthermore, we show that YAP/TAZ expression is triggered in the heart cells located at the infarct border zone. Our results suggest a fundamental role for the YAP/TAZ axis in the response of resident progenitor cells to the modifications in microenvironment nanostructure and mechanics, thereby contributing to the maintenance of myocardial homeostasis in the adult heart. These proteins are indicated as potential targets to control cardiac progenitor cell fate by materials design. © 2014 American Chemical Society.

  14. Endothelial cells control pancreatic cell fate at defined stages through EGFL7 signaling.

    Science.gov (United States)

    Kao, Der-I; Lacko, Lauretta A; Ding, Bi-Sen; Huang, Chen; Phung, Kathleen; Gu, Guoqiang; Rafii, Shahin; Stuhlmann, Heidi; Chen, Shuibing

    2015-02-10

    Although endothelial cells have been shown to affect mouse pancreatic development, their precise function in human development remains unclear. Using a coculture system containing human embryonic stem cell (hESC)-derived progenitors and endothelial cells, we found that endothelial cells play a stage-dependent role in pancreatic development, in which they maintain pancreatic progenitor (PP) self-renewal and impair further differentiation into hormone-expressing cells. The mechanistic studies suggest that the endothelial cells act through the secretion of EGFL7. Consistently, endothelial overexpression of EGFL7 in vivo using a transgenic mouse model resulted in an increase of PP proliferation rate and a decrease of differentiation toward endocrine cells. These studies not only identified the role of EGFL7 as the molecular handle involved in the crosstalk between endothelium and pancreatic epithelium, but also provide a paradigm for using hESC stepwise differentiation to dissect the stage-dependent roles of signals controlling organogenesis. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  15. Endothelial Cells Control Pancreatic Cell Fate at Defined Stages through EGFL7 Signaling

    Directory of Open Access Journals (Sweden)

    Der-I Kao

    2015-02-01

    Full Text Available Although endothelial cells have been shown to affect mouse pancreatic development, their precise function in human development remains unclear. Using a coculture system containing human embryonic stem cell (hESC-derived progenitors and endothelial cells, we found that endothelial cells play a stage-dependent role in pancreatic development, in which they maintain pancreatic progenitor (PP self-renewal and impair further differentiation into hormone-expressing cells. The mechanistic studies suggest that the endothelial cells act through the secretion of EGFL7. Consistently, endothelial overexpression of EGFL7 in vivo using a transgenic mouse model resulted in an increase of PP proliferation rate and a decrease of differentiation toward endocrine cells. These studies not only identified the role of EGFL7 as the molecular handle involved in the crosstalk between endothelium and pancreatic epithelium, but also provide a paradigm for using hESC stepwise differentiation to dissect the stage-dependent roles of signals controlling organogenesis.

  16. Fate of Salmonella enterica and Enterohemorrhagic Escherichia coli cells, Artificially Internalized into Vegetable Seeds during Germination.

    Science.gov (United States)

    Liu, Da; Cui, Yue; Walcott, Ronald; Chen, Jinru

    2017-10-27

    Vegetable seeds contaminated with bacterial pathogens have been linked to fresh produce-associated outbreaks of gastrointestinal infections. This study was undertaken to observe the physiological behavior of Salmonella enterica and enterohemorrhagic Escherichia coli (EHEC) cells, artificially internalized into vegetable seeds during the germination process. Surface-decontaminated seeds of alfalfa, fenugreek, lettuce, and tomato were vacuum-infiltrated with four individual strains of Salmonella or EHEC. Contaminated seeds were germinated at 25°C for 9 days and different sprout/seedling tissues were microbiologically analyzed every other day. Internalization of Salmonella and EHEC cells into vegetable seeds was confirmed by the absence of pathogens in seed-rinsing water and presence of pathogens in seed homogenates after post-internalization seed surface decontamination. Results show that 317 (62%) and 343 (67%) out of the 512 collected sprout/seedling tissue samples were positive for Salmonella and EHEC, respectively. Average Salmonella populations were significantly higher (pcell populations on sprout/seedling tissues than other strains used in the study. Salmonella and EHEC populations from fenugreek and alfalfa tissues were significantly higher than those from tomato and lettuce tissues. The study observed the fate of internalized human pathogens on germinating vegetable seeds and sprout/seedling tissues and emphasized the importance of using pathogen-free seeds for sprout production.IMPORTANCE Internalization of microorganisms into vegetable seeds could occur naturally and represents a possible pathway of vegetable seed contamination by human pathogens. The present study investigated the ability of two important bacterial pathogens, Salmonella and EHEC, when artificially internalized into vegetable seeds, to grow and disseminate along vegetable sprouts/seedlings during germination. Data of the study revealed that the pathogen cells artificially internalized

  17. ELT-1, a GATA-like transcription factor, is required for epidermal cell fates in Caenorhabditis elegans embryos.

    Science.gov (United States)

    Page, B D; Zhang, W; Steward, K; Blumenthal, T; Priess, J R

    1997-07-01

    Epidermal cells are generated during Caenorhabditis elegans embryogenesis by several distinct lineage patterns. These patterns are controlled by maternal genes that determine the identities of early embryonic blastomeres. We show that the embryonically expressed gene elt-1, which was shown previously to encode a GATA-like transcription factor, is required for the production of epidermal cells by each of these lineages. Depending on their lineage history, cells that become epidermal in wild-type embryos become either neurons or muscle cells in elt-1 mutant embryos. The ELT-1 protein is expressed in epidermal cells and in their precursors. We propose that elt-1 functions at an early step in the specification of epidermal cell fates.

  18. Stochastic descriptors to study the fate and potential of naive T cell clonotypes in the periphery.

    Science.gov (United States)

    Artalejo, J R; Gómez-Corral, A; López-García, M; Molina-París, C

    2017-02-01

    The population of naive T cells in the periphery is best described by determining both its T cell receptor diversity, or number of clonotypes, and the sizes of its clonal subsets. In this paper, we make use of a previously introduced mathematical model of naive T cell homeostasis, to study the fate and potential of naive T cell clonotypes in the periphery. This is achieved by the introduction of several new stochastic descriptors for a given naive T cell clonotype, such as its maximum clonal size, the time to reach this maximum, the number of proliferation events required to reach this maximum, the rate of contraction of the clonotype during its way to extinction, as well as the time to a given number of proliferation events. Our results show that two fates can be identified for the dynamics of the clonotype: extinction in the short-term if the clonotype experiences too hostile a peripheral environment, or establishment in the periphery in the long-term. In this second case the probability mass function for the maximum clonal size is bimodal, with one mode near one and the other mode far away from it. Our model also indicates that the fate of a recent thymic emigrant (RTE) during its journey in the periphery has a clear stochastic component, where the probability of extinction cannot be neglected, even in a friendly but competitive environment. On the other hand, a greater deterministic behaviour can be expected in the potential size of the clonotype seeded by the RTE in the long-term, once it escapes extinction.

  19. The roles of Sertoli cells in fate determinations of spermatogonial stem cells

    Directory of Open Access Journals (Sweden)

    Maryam Khanehzad

    2016-03-01

    Full Text Available Background: Spermatogenesis is a complex and highly organized process of proliferation and differentiation of spermatogonial stem cells. Spermatogonial stem cells (SSCs as a unique stem cell have the potential to self-renewal, differentiation and transmit genetic information to the next generation and play a vital role in maintaining fertility. Sertoli cells as the only somatic cells within the seminiferous epithelium play central roles in the formation of niche and balance between self-renewal and differentiation by secrete many growth factors. Given the importance and widespread use of SSCs, particularly in the treatment of infertility, the aim of this study was to create an optimal environment for the proliferation of SSCs. So we decided to study of undifferentiated (ID4 and differentiated (c-Kit gene expression in SSCs followed by co-culture with Sertoli cells for a one-month. Methods: This experimental study was conducted from November 2013 to December 2014 in Department of Anatomy, School of Medicine, Tehran University of Medical Sciences, on immature NMRI mouse (6-3 days old. Initially, Sertoli cells and SSCs were isolated from neonates mouse testes during the two-step enzymatic digestion characteristics Sertoli cells with vimentin marker and SSCs with promyelocytic leukemia zinc-finger (PLZF marker were confirmed. Then SSCs were cultured in two groups: co-culture with Sertoli and without co-culture (control. Undifferentiated (ID4 and differentiation (c-Kit gene expression were evaluated by Real-time PCR technique. Results: Spermatogonial stem cells purity was obtained 66.91% by flow cytometry. The relative expression levels of gene ID4 in co-culture group at the end of each week, compared to the control group showed a significant increase (P<0.05. While the expression of this gene significantly decreased in each group over time (P<0.05. The results of the comparison of the relative expression of c-Kit gene in co-culture group are

  20. Single-Cell Landscape of Transcriptional Heterogeneity and Cell Fate Decisions during Mouse Early Gastrulation

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    Hisham Mohammed

    2017-08-01

    Full Text Available The mouse inner cell mass (ICM segregates into the epiblast and primitive endoderm (PrE lineages coincident with implantation of the embryo. The epiblast subsequently undergoes considerable expansion of cell numbers prior to gastrulation. To investigate underlying regulatory principles, we performed systematic single-cell RNA sequencing (seq of conceptuses from E3.5 to E6.5. The epiblast shows reactivation and subsequent inactivation of the X chromosome, with Zfp57 expression associated with reactivation and inactivation together with other candidate regulators. At E6.5, the transition from epiblast to primitive streak is linked with decreased expression of polycomb subunits, suggesting a key regulatory role. Notably, our analyses suggest elevated transcriptional noise at E3.5 and within the non-committed epiblast at E6.5, coinciding with exit from pluripotency. By contrast, E6.5 primitive streak cells became highly synchronized and exhibit a shortened G1 cell-cycle phase, consistent with accelerated proliferation. Our study systematically charts transcriptional noise and uncovers molecular processes associated with early lineage decisions.

  1. A cell cycle kinase with tandem sensory PAS domains integrates cell fate cues

    Science.gov (United States)

    Mann, Thomas H.; Seth Childers, W.; Blair, Jimmy A.; Eckart, Michael R.; Shapiro, Lucy

    2016-01-01

    All cells must integrate sensory information to coordinate developmental events in space and time. The bacterium Caulobacter crescentus uses two-component phospho-signalling to regulate spatially distinct cell cycle events through the master regulator CtrA. Here, we report that CckA, the histidine kinase upstream of CtrA, employs a tandem-PAS domain sensor to integrate two distinct spatiotemporal signals. Using CckA reconstituted on liposomes, we show that one PAS domain modulates kinase activity in a CckA density-dependent manner, mimicking the stimulation of CckA kinase activity that occurs on its transition from diffuse to densely packed at the cell poles. The second PAS domain interacts with the asymmetrically partitioned second messenger cyclic-di-GMP, inhibiting kinase activity while stimulating phosphatase activity, consistent with the selective inactivation of CtrA in the incipient stalked cell compartment. The integration of these spatially and temporally regulated signalling events within a single signalling receptor enables robust orchestration of cell-type-specific gene regulation. PMID:27117914

  2. Tetraploidization or autophagy: The ultimate fate of senescent human endometrial stem cells under ATM or p53 inhibition.

    Science.gov (United States)

    Borodkina, Aleksandra V; Shatrova, Alla N; Deryabin, Pavel I; Grukova, Anastasiya A; Nikolsky, Nikolay N; Burova, Elena B

    2016-01-01

    Previously we demonstrated that endometrium-derived human mesenchymal stem cells (hMESCs) via activation of the ATM/p53/p21/Rb pathway enter the premature senescence in response to oxidative stress. Down regulation effects of the key components of this signaling pathway, particularly ATM and p53, on a fate of stressed hMESCs have not yet been investigated. In the present study by using the specific inhibitors Ku55933 and Pifithrin-α, we confirmed implication of both ATM and p53 in H(2)O(2)-induced senescence of hMESCs. ATM or p53 down regulation was shown to modulate differently the cellular fate of H(2)O(2)-treated hMESCs. ATM inhibition allowed H(2)O(2)-stimulated hMESCs to escape the permanent cell cycle arrest due to loss of the functional ATM/p53/p21/Rb pathway, and induced bypass of mitosis and re-entry into S phase, resulting in tetraploid cells. On the contrary, suppression of the p53 transcriptional activity caused a pronounced cell death of H(2)O(2)-treated hMESCs via autophagy induction. The obtained data clearly demonstrate that down regulation of ATM or p53 shifts senescence of human endometrial stem cells toward tetraploidization or autophagy.

  3. In vivo fate analysis reveals the multipotent and self-renewal features of embryonic AspM expressing cells.

    Science.gov (United States)

    Marinaro, Cinzia; Butti, Erica; Bergamaschi, Andrea; Papale, Alessandro; Furlan, Roberto; Comi, Giancarlo; Martino, Gianvito; Muzio, Luca

    2011-04-29

    Radial Glia (RG) cells constitute the major population of neural progenitors of the mouse developing brain. These cells are located in the ventricular zone (VZ) of the cerebral cortex and during neurogenesis they support the generation of cortical neurons. Later on, during brain maturation, RG cells give raise to glial cells and supply the adult mouse brain of Neural Stem Cells (NSC). Here we used a novel transgenic mouse line expressing the CreER(T2) under the control of AspM promoter to monitor the progeny of an early cohort of RG cells during neurogenesis and in the post natal brain. Long term fate mapping experiments demonstrated that AspM-expressing RG cells are multi-potent, as they can generate neurons, astrocytes and oligodendrocytes of the adult mouse brain. Furthermore, AspM descendants give also rise to proliferating progenitors in germinal niches of both developing and post natal brains. In the latter--i.e. the Sub Ventricular Zone--AspM descendants acquired several feature of neural stem cells, including the capability to generate neurospheres in vitro. We also performed the selective killing of these early progenitors by using a Nestin-GFP(flox)-TK allele. The forebrain specific loss of early AspM expressing cells caused the elimination of most of the proliferating cells of brain, a severe derangement of the ventricular zone architecture, and the impairment of the cortical lamination. We further demonstrated that AspM is expressed by proliferating cells of the adult mouse SVZ that can generate neuroblasts fated to become olfactory bulb neurons.

  4. In vivo fate analysis reveals the multipotent and self-renewal features of embryonic AspM expressing cells.

    Directory of Open Access Journals (Sweden)

    Cinzia Marinaro

    Full Text Available Radial Glia (RG cells constitute the major population of neural progenitors of the mouse developing brain. These cells are located in the ventricular zone (VZ of the cerebral cortex and during neurogenesis they support the generation of cortical neurons. Later on, during brain maturation, RG cells give raise to glial cells and supply the adult mouse brain of Neural Stem Cells (NSC. Here we used a novel transgenic mouse line expressing the CreER(T2 under the control of AspM promoter to monitor the progeny of an early cohort of RG cells during neurogenesis and in the post natal brain. Long term fate mapping experiments demonstrated that AspM-expressing RG cells are multi-potent, as they can generate neurons, astrocytes and oligodendrocytes of the adult mouse brain. Furthermore, AspM descendants give also rise to proliferating progenitors in germinal niches of both developing and post natal brains. In the latter--i.e. the Sub Ventricular Zone--AspM descendants acquired several feature of neural stem cells, including the capability to generate neurospheres in vitro. We also performed the selective killing of these early progenitors by using a Nestin-GFP(flox-TK allele. The forebrain specific loss of early AspM expressing cells caused the elimination of most of the proliferating cells of brain, a severe derangement of the ventricular zone architecture, and the impairment of the cortical lamination. We further demonstrated that AspM is expressed by proliferating cells of the adult mouse SVZ that can generate neuroblasts fated to become olfactory bulb neurons.

  5. C. elegans GATA factors EGL-18 and ELT-6 function downstream of Wnt signaling to maintain the progenitor fate during larval asymmetric divisions of the seam cells.

    Science.gov (United States)

    Gorrepati, Lakshmi; Thompson, Kenneth W; Eisenmann, David M

    2013-05-01

    The C. elegans seam cells are lateral epithelial cells arrayed in a single line from anterior to posterior that divide in an asymmetric, stem cell-like manner during larval development. These asymmetric divisions are regulated by Wnt signaling; in most divisions, the posterior daughter in which the Wnt pathway is activated maintains the progenitor seam fate, while the anterior daughter in which the Wnt pathway is not activated adopts a differentiated hypodermal fate. Using mRNA tagging and microarray analysis, we identified the functionally redundant GATA factor genes egl-18 and elt-6 as Wnt pathway targets in the larval seam cells. EGL-18 and ELT-6 have previously been shown to be required for initial seam cell specification in the embryo. We show that in larval seam cell asymmetric divisions, EGL-18 is expressed strongly in the posterior seam-fated daughter. egl-18 and elt-6 are necessary for larval seam cell specification, and for hypodermal to seam cell fate transformations induced by ectopic Wnt pathway overactivation. The TCF homolog POP-1 binds a site in the egl-18 promoter in vitro, and this site is necessary for robust seam cell expression in vivo. Finally, larval overexpression of EGL-18 is sufficient to drive expression of a seam marker in other hypodermal cells in wild-type animals, and in anterior hypodermal-fated daughters in a Wnt pathway-sensitized background. These data suggest that two GATA factors that are required for seam cell specification in the embryo independently of Wnt signaling are reused downstream of Wnt signaling to maintain the progenitor fate during stem cell-like divisions in larval development.

  6. SMAD2 and p38 signaling pathways act in concert to determine XY primordial germ cell fate in mice.

    Science.gov (United States)

    Wu, Quan; Fukuda, Kurumi; Weinstein, Michael; Graff, Jonathan M; Saga, Yumiko

    2015-02-01

    The sex of primordial germ cells (PGCs) is determined in developing gonads on the basis of cues from somatic cells. In XY gonads, sex-determining region Y (SRY) triggers fibroblast growth factor 9 (FGF9) expression in somatic cells. FGF signaling, together with downstream nodal/activin signaling, promotes male differentiation in XY germ cells by suppressing retinoic acid (RA)-dependent meiotic entry and inducing male-specific genes. However, the mechanism by which nodal/activin signaling regulates XY PGC fate is unknown. We uncovered the roles of SMAD2/3 and p38 MAPK, the putative downstream factors of nodal/activin signaling, in PGC sexual fate decision. We found that conditional deletion of Smad2, but not Smad3, from XY PGCs led to a loss of male-specific gene expression. Moreover, suppression of RA signaling did not rescue male-specific gene expression in Smad2-mutant testes, indicating that SMAD2 signaling promotes male differentiation in a RA-independent manner. By contrast, we found that p38 signaling has an important role in the suppression of RA signaling. The Smad2 deletion did not disrupt the p38 signaling pathway even though Nodal expression was significantly reduced, suggesting that p38 was not regulated by nodal signaling in XY PGCs. Additionally, the inhibition of p38 signaling in the Smad2-mutant testes severely impeded XY PGC differentiation and induced meiosis. In conclusion, we propose a model in which p38 and SMAD2 signaling coordinate to determine the sexual fate of XY PGCs. © 2015. Published by The Company of Biologists Ltd.

  7. Hydrogel formulation determines cell fate of fetal and adult neural progenitor cells

    Directory of Open Access Journals (Sweden)

    Emily R. Aurand

    2014-01-01

    Full Text Available Hydrogels provide a unique tool for neural tissue engineering. These materials can be customized for certain functions, i.e. to provide cell/drug delivery or act as a physical scaffold. Unfortunately, hydrogel complexities can negatively impact their biocompatibility, resulting in unintended consequences. These adverse effects may be combated with a better understanding of hydrogel chemical, physical, and mechanical properties, and how these properties affect encapsulated neural cells. We defined the polymerization and degradation rates and compressive moduli of 25 hydrogels formulated from different concentrations of hyaluronic acid (HA and poly(ethylene glycol (PEG. Changes in compressive modulus were driven primarily by the HA concentration. The in vitro biocompatibility of fetal-derived (fNPC and adult-derived (aNPC neural progenitor cells was dependent on hydrogel formulation. Acute survival of fNPC benefited from hydrogel encapsulation. NPC differentiation was divergent: fNPC differentiated into mostly glial cells, compared with neuronal differentiation of aNPC. Differentiation was influenced in part by the hydrogel mechanical properties. This study indicates that there can be a wide range of HA and PEG hydrogels compatible with NPC. Additionally, this is the first study comparing hydrogel encapsulation of NPC derived from different aged sources, with data suggesting that fNPC and aNPC respond dissimilarly within the same hydrogel formulation.

  8. Hydrogel formulation determines cell fate of fetal and adult neural progenitor cells

    Science.gov (United States)

    Wagner, Jennifer L.; Shandas, Robin; Bjugstad, Kimberly B.

    2014-01-01

    Hydrogels provide a unique tool for neural tissue engineering. These materials can be customized for certain functions, i.e. to provide cell/drug delivery or act as a physical scaffold. Unfortunately, hydrogel complexities can negatively impact their biocompatibility, resulting in unintended consequences. These adverse effects may be combated with a better understanding of hydrogel chemical, physical, and mechanical properties, and how these properties affect encapsulated neural cells. We defined the polymerization and degradation rates and compressive moduli of 25 hydrogels formulated from different concentrations of hyaluronic acid (HA) and poly(ethylene glycol) (PEG). Changes in compressive modulus were driven primarily by the HA concentration. The in vitro biocompatibility of fetal-derived (fNPC) and adult-derived (aNPC) neural progenitor cells was dependent on hydrogel formulation. Acute survival of fNPC benefited from hydrogel encapsulation. NPC differentiation was divergent: fNPC differentiated into mostly glial cells, compared with neuronal differentiation of aNPC. Differentiation was influenced in part by the hydrogel mechanical properties. This study indicates that there can be a wide range of HA and PEG hydrogels compatible with NPC. Additionally, this is the first study comparing hydrogel encapsulation of NPC derived from different aged sources, with data suggesting that fNPC and aNPC respond dissimilarly within the same hydrogel formulation. PMID:24141109

  9. CAM and Cell Fate Targeting: Molecular and Energetic Insights into Cell Growth and Differentiation

    Directory of Open Access Journals (Sweden)

    Carlo Ventura

    2005-01-01

    Full Text Available Evidence-based medicine is switching from the analysis of single diseases at a time toward an integrated assessment of a diseased person. Complementary and alternative medicine (CAM offers multiple holistic approaches, including osteopathy, homeopathy, chiropractic, acupuncture, herbal and energy medicine and meditation, all potentially impacting on major human diseases. It is now becoming evident that acupuncture can modify the expression of different endorphin genes and the expression of genes encoding for crucial transcription factors in cellular homeostasis. Extremely low frequency magnetic fields have been found to prime the commitment to a myocardial lineage in mouse embryonic stem cells, suggesting that magnetic energy may direct stem cell differentiation into specific cellular phenotypes without the aid of gene transfer technologies. This finding may pave the way to novel approaches in tissue engineering and regeneration. Different ginseng extracts have been shown to modulate growth and differentiation in pluripotent cells and to exert wound-healing and antitumor effects through opposing activities on the vascular system, prompting the hypothesis that ancient compounds may be the target for new logics in cell therapy. These observations and the subtle entanglement among different CAM systems suggest that CAM modalities may deeply affect both the signaling and transcriptional level of cellular homeostasis. Such a perception holds promises for a new era in CAM, prompting reproducible documentation of biological responses to CAM-related strategies and compounds. To this end, functional genomics and proteomics and the comprehension of the cell signaling networks may substantially contribute to the development of a molecular evidence–based CAM.

  10. CAM and cell fate targeting: molecular and energetic insights into cell growth and differentiation.

    Science.gov (United States)

    Ventura, Carlo

    2005-09-01

    Evidence-based medicine is switching from the analysis of single diseases at a time toward an integrated assessment of a diseased person. Complementary and alternative medicine (CAM) offers multiple holistic approaches, including osteopathy, homeopathy, chiropractic, acupuncture, herbal and energy medicine and meditation, all potentially impacting on major human diseases. It is now becoming evident that acupuncture can modify the expression of different endorphin genes and the expression of genes encoding for crucial transcription factors in cellular homeostasis. Extremely low frequency magnetic fields have been found to prime the commitment to a myocardial lineage in mouse embryonic stem cells, suggesting that magnetic energy may direct stem cell differentiation into specific cellular phenotypes without the aid of gene transfer technologies. This finding may pave the way to novel approaches in tissue engineering and regeneration. Different ginseng extracts have been shown to modulate growth and differentiation in pluripotent cells and to exert wound-healing and antitumor effects through opposing activities on the vascular system, prompting the hypothesis that ancient compounds may be the target for new logics in cell therapy. These observations and the subtle entanglement among different CAM systems suggest that CAM modalities may deeply affect both the signaling and transcriptional level of cellular homeostasis. Such a perception holds promises for a new era in CAM, prompting reproducible documentation of biological responses to CAM-related strategies and compounds. To this end, functional genomics and proteomics and the comprehension of the cell signaling networks may substantially contribute to the development of a molecular evidence-based CAM.

  11. The redox function of APE1 is involved in the differentiation process of stem cells toward a neuronal cell fate.

    Directory of Open Access Journals (Sweden)

    Rossana Domenis

    Full Text Available Low-to-moderate levels of reactive oxygen species (ROS govern different steps of neurogenesis via molecular pathways that have been decrypted only partially. Although it has been postulated that redox-sensitive molecules are involved in neuronal differentiation, the molecular bases for this process have not been elucidated yet. The aim of this work was therefore to study the role played by the redox-sensitive, multifunctional protein APE1/Ref-1 (APE1 in the differentiation process of human adipose tissue-derived multipotent adult stem cells (hAT-MASC and embryonic carcinoma stem cells (EC towards a neuronal phenotype.Applying a definite protocol, hAT-MASC can adopt a neural fate. During this maturation process, differentiating cells significantly increase their intracellular Reactive Oxygen Species (ROS levels and increase the APE1 nuclear fraction bound to chromatin. This latter event is paralleled by the increase of nuclear NF-κB, a transcription factor regulated by APE1 in a redox-dependent fashion. Importantly, the addition of the antioxidant N-acetyl cysteine (NAC to the differentiation medium partially prevents the nuclear accumulation of APE1, increasing the neuronal differentiation of hAT-MASC. To investigate the involvement of APE1 in the differentiation process, we employed E3330, a specific inhibitor of the APE1 redox function. The addition of E3330, either to the neurogenic embryonic carcinoma cell line NT2-D1or to hAT-MASC, increases the differentiation of stem cells towards a neural phenotype, biasing the differentiation towards specific subtypes, such as dopaminergic cells. In conclusion, during the differentiation process of stem cells towards a neuroectodermic phenotype, APE1 is recruited, in a ROS-dependent manner, to the chromatin. This event is associated with an inhibitory effect of APE1 on neurogenesis that may be reversed by E3330. Therefore, E3330 may be employed both to boost neural differentiation and to bias the

  12. Mammary-Stem-Cell-Based Somatic Mouse Models Reveal Breast Cancer Drivers Causing Cell Fate Dysregulation

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    Zheng Zhang

    2016-09-01

    Full Text Available Cancer genomics has provided an unprecedented opportunity for understanding genetic causes of human cancer. However, distinguishing which mutations are functionally relevant to cancer pathogenesis remains a major challenge. We describe here a mammary stem cell (MaSC organoid-based approach for rapid generation of somatic genetically engineered mouse models (GEMMs. By using RNAi and CRISPR-mediated genome engineering in MaSC-GEMMs, we have discovered that inactivation of Ptpn22 or Mll3, two genes mutated in human breast cancer, greatly accelerated PI3K-driven mammary tumorigenesis. Using these tumor models, we have also identified genetic alterations promoting tumor metastasis and causing resistance to PI3K-targeted therapy. Both Ptpn22 and Mll3 inactivation resulted in disruption of mammary gland differentiation and an increase in stem cell activity. Mechanistically, Mll3 deletion enhanced stem cell activity through activation of the HIF pathway. Thus, our study has established a robust in vivo platform for functional cancer genomics and has discovered functional breast cancer mutations.

  13. Stochasticity of intranuclear biochemical reaction processes controls the final decision of cell fate associated with DNA damage.

    Science.gov (United States)

    Iwamoto, Kazunari; Hamada, Hiroyuki; Eguchi, Yukihiro; Okamoto, Masahiro

    2014-01-01

    A massive integrative mathematical model of DNA double-strand break (DSB) generation, DSB repair system, p53 signaling network, and apoptosis induction pathway was constructed to explore the dominant factors of unknown criteria of cell fate decision. In the proposed model, intranuclear reactions were modeled as stochastic processes and cytoplasmic reactions as deterministic processes, and both reaction sets were simulated simultaneously. The simulated results at the single-cell level showed that the model generated several sustained oscillations (pulses) of p53, Mdm2, ATM, and Wip1, and cell-to-cell variability in the number of p53 pulses depended on IR intensity. In cell populations, the model generated damped p53 oscillations, and IR intensity affected the amplitude of the first p53 oscillation. Cells were then subjected to the same IR dose exhibiting apoptosis induction variability. These simulated results are in quantitative agreement with major biological findings observed in human breast cancer epithelial MCF7, NIH3T3, and fibrosarcoma cells, demonstrating that the proposed model was concededly biologically appropriate. Statistical analysis of the simulated results shows that the generation of multiple p53 pulses is a prerequisite for apoptosis induction. Furthermore, cells exhibited considerable individual variability in p53 dynamics, which correlated with intrinsic apoptosis induction. The simulated results based on the proposed model demonstrated that the stochasticity of intranuclear biochemical reaction processes controls the final decision of cell fate associated with DNA damage. Applying stochastic simulation to an exploration of intranuclear biochemical reaction processes is indispensable in enhancing the understanding of the dynamic characteristics of biological multi-layered systems of higher organisms.

  14. Dynamics of p53: A Master Decider of Cell Fate

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    Qingyin Luo

    2017-02-01

    Full Text Available Cellular stress‐induced temporal alterations—i.e., dynamics—are typically exemplified  by the dynamics of p53 that serve as a master to determine cell fate. p53 dynamics were initially  identified as the variations of p53 protein levels. However, a growing number of studies have  shown that p53 dynamics are also manifested in variations in the activity, spatial location, and  posttranslational modifications of p53 proteins, as well as the interplay among all p53 dynamical  features. These are essential in determining a specific outcome of cell fate. In this review, we  discuss the importance of the multifaceted features of p53 dynamics and their roles in the cell fate  decision process, as well as their potential applications in p53‐based cancer therapy. The review  provides new insights into p53 signaling pathways and their potentials in the development of new  strategies in p53‐based cancer therapy.

  15. Control of liver cell fate decision by a gradient of TGF beta signaling modulated by Onecut transcription factors.

    Science.gov (United States)

    Clotman, Frédéric; Jacquemin, Patrick; Plumb-Rudewiez, Nicolas; Pierreux, Christophe E; Van der Smissen, Patrick; Dietz, Harry C; Courtoy, Pierre J; Rousseau, Guy G; Lemaigre, Frédéric P

    2005-08-15

    During liver development, hepatocytes and biliary cells differentiate from common progenitors called hepatoblasts. The factors that control hepatoblast fate decision are unknown. Here we report that a gradient of activin/TGFbeta signaling controls hepatoblast differentiation. High activin/TGFbeta signaling is required near the portal vein for differentiation of biliary cells. The Onecut transcription factors HNF-6 and OC-2 inhibit activin/TGFbeta signaling in the parenchyma, and this allows normal hepatocyte differentiation. In the absence of Onecut factors, the shape of the activin/TGFbeta gradient is perturbed and the hepatoblasts differentiate into hybrid cells that display characteristics of both hepatocytes and biliary cells. Thus, a gradient of activin/TGFbeta signaling modulated by Onecut factors is required to segregate the hepatocytic and the biliary lineages.

  16. Control of liver cell fate decision by a gradient of TGFβ signaling modulated by Onecut transcription factors

    Science.gov (United States)

    Clotman, Frédéric; Jacquemin, Patrick; Plumb-Rudewiez, Nicolas; Pierreux, Christophe E.; Van der Smissen, Patrick; Dietz, Harry C.; Courtoy, Pierre J.; Rousseau, Guy G.; Lemaigre, Frédéric P.

    2005-01-01

    During liver development, hepatocytes and biliary cells differentiate from common progenitors called hepatoblasts. The factors that control hepatoblast fate decision are unknown. Here we report that a gradient of activin/TGFβ signaling controls hepatoblast differentiation. High activin/TGFβ signaling is required near the portal vein for differentiation of biliary cells. The Onecut transcription factors HNF-6 and OC-2 inhibit activin/TGFβ signaling in the parenchyma, and this allows normal hepatocyte differentiation. In the absence of Onecut factors, the shape of the activin/TGFβ gradient is perturbed and the hepatoblasts differentiate into hybrid cells that display characteristics of both hepatocytes and biliary cells. Thus, a gradient of activin/TGFβ signaling modulated by Onecut factors is required to segregate the hepatocytic and the biliary lineages. PMID:16103213

  17. The identity and fate decision control of spermatogonial stem cells: where is the point of no return?

    Science.gov (United States)

    Nagano, Makoto C; Yeh, Jonathan R

    2013-01-01

    Spermatogonial stem cells (SSCs) are stem cells of the male germ line and support spermatogenesis for a lifetime after puberty by continuously self-renewing and generating committed progenitors. Accordingly, SSCs are defined functionally by their ability to regenerate and maintain spermatogenesis and are detected unequivocally based on their regenerative capacity. Here, we summarize past achievements of morphological and functional studies of SSCs and discuss issues to be addressed in future investigations. Using the mouse as a model organism, our particular foci are the heterogeneity of primitive spermatogonia and the maintenance of and exit from the stem cell state. By comparing to the biology of other stem cell types and organisms, we also propose possibilities and hypotheses for potential mechanisms of SSC fate decision control, involving stochastic entry into the commitment process and the interplay between SSCs and their descendants that coordinates SSC self-renewal and differentiation. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. hESC Differentiation toward an Autonomic Neuronal Cell Fate Depends on Distinct Cues from the Co-Patterning Vasculature

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    Lisette M. Acevedo

    2015-06-01

    Full Text Available To gain insight into the cellular and molecular cues that promote neurovascular co-patterning at the earliest stages of human embryogenesis, we developed a human embryonic stem cell model to mimic the developing epiblast. Contact of ectoderm-derived neural cells with mesoderm-derived vasculature is initiated via the neural crest (NC, not the neural tube (NT. Neurovascular co-patterning then ensues with specification of NC toward an autonomic fate requiring vascular endothelial cell (EC-secreted nitric oxide (NO and direct contact with vascular smooth muscle cells (VSMCs via T-cadherin-mediated homotypic interactions. Once a neurovascular template has been established, NT-derived central neurons then align themselves with the vasculature. Our findings reveal that, in early human development, the autonomic nervous system forms in response to distinct molecular cues from VSMCs and ECs, providing a model for how other developing lineages might coordinate their co-patterning.

  19. Tracing Conidial Fate and Measuring Host Cell Antifungal Activity Using a Reporter of Microbial Viability in the Lung

    Directory of Open Access Journals (Sweden)

    Anupam Jhingran

    2012-12-01

    Full Text Available Fluorescence can be harnessed to monitor microbial fate and to investigate functional outcomes of individual microbial cell-host cell encounters at portals of entry in native tissue environments. We illustrate this concept by introducing fluorescent Aspergillus reporter (FLARE conidia that simultaneously report phagocytic uptake and fungal viability during cellular interactions with the murine respiratory innate immune system. Our studies using FLARE conidia reveal stepwise and cell-type-specific requirements for CARD9 and Syk, transducers of C-type lectin receptor and integrin signals, in neutrophil recruitment, conidial uptake, and conidial killing in the lung. By achieving single-event resolution in defined leukocyte populations, the FLARE method enables host cell profiling on the basis of pathogen uptake and killing and may be extended to other pathogens in diverse model host organisms to query molecular, cellular, and pharmacologic mechanisms that shape host-microbe interactions.

  20. Neuronal cell fate decisions:  O2 and CO2 sensing neurons require egl-13/Sox5

    DEFF Research Database (Denmark)

    Gramstrup Petersen, Jakob; Pocock, Roger David John

    2013-01-01

    to drive O2 and CO2 sensing neuron fate and is therefore essential for O2 and CO2 sensing-induced behaviors. Through systematic dissection of the egl-13 promoter we identified upstream regulators of egl-13 and proposed a model of how differentiation of O2 and CO2 sensing neurons is regulated......We recently conducted a study that aimed to describe the differentiation mechanisms used to generate O2 and CO2 sensing neurons in C. elegans. We identified egl-13/Sox5 to be required for the differentiation of both O2 and CO2 sensing neurons. We found that egl-13 functions cell autonomously...

  1. Model complexity and choice of model approaches for practical simulations of CO2 injection, migration, leakage and long-term fate

    Energy Technology Data Exchange (ETDEWEB)

    Celia, Michael A. [Princeton Univ., NJ (United States)

    2016-12-30

    This report documents the accomplishments achieved during the project titled “Model complexity and choice of model approaches for practical simulations of CO2 injection,migration, leakage and long-term fate” funded by the US Department of Energy, Office of Fossil Energy. The objective of the project was to investigate modeling approaches of various levels of complexity relevant to geologic carbon storage (GCS) modeling with the goal to establish guidelines on choice of modeling approach.

  2. m6A RNA modification controls cell fate transition in mammalian embryonic stem cells

    Science.gov (United States)

    Batista, Pedro J; Molinie, Benoit; Wang, Jinkai; Qu, Kun; Zhang, Jiajing; Li, Lingjie; Bouley, Donna M; Lujan, Ernesto; Haddad, Bahareh; Daneshvar, Kaveh; Carter, Ava C; Flynn, Ryan A; Zhou, Chan; Lim, Kok-Seong; Dedon, Peter; Wernig, Marius; Mullen, Alan C; Xing, Yi; Giallourakis, Cosmas C; Chang, Howard Y

    2014-01-01

    SUMMARY N6-methyl-adenosine (m6A) is the most abundant modification on messenger RNAs and is linked to human diseases, but its functions in mammalian development are poorly understood. Here we reveal the evolutionary conservation and function of m6A by mapping the m6A methylome in mouse and human embryonic stem cells. Thousands of messenger and long noncoding RNAs show conserved m6A modification, including transcripts encoding core pluripotency transcription factors. m6A is enriched over 3′ untranslated regions at defined sequence motifs, and marks unstable transcripts, including transcripts turned over upon differentiation. Genetic inactivation or depletion of mouse and human Mettl3, one of the m6A methylases, led to m6A erasure on select target genes, prolonged Nanog expression upon differentiation, and impaired ESC’s exit from self-renewal towards differentiation into several lineages in vitro and in vivo. Thus, m6A is a mark of transcriptome flexibility required for stem cells to differentiate to specific lineages. PMID:25456834

  3. Loss of Ptf1a Leads to a Widespread Cell-Fate Misspecification in the Brainstem, Affecting the Development of Somatosensory and Viscerosensory Nuclei

    Science.gov (United States)

    Iskusnykh, Igor Y.; Steshina, Ekaterina Y.

    2016-01-01

    The brainstem contains diverse neuronal populations that regulate a wide range of processes vital to the organism. Proper cell-fate specification decisions are critical to achieve neuronal diversity in the CNS, but the mechanisms regulating cell-fate specification in the developing brainstem are poorly understood. Previously, it has been shown that basic helix-loop-helix transcription factor Ptf1a is required for the differentiation and survival of neurons of the inferior olivary and cochlear brainstem nuclei, which contribute to motor coordination and sound processing, respectively. In this study, we show that the loss of Ptf1a compromises the development of the nucleus of the solitary tract, which processes viscerosensory information, and the spinal and principal trigeminal nuclei, which integrate somatosensory information of the face. Combining genetic fate-mapping, birth-dating, and gene expression studies, we found that at least a subset of brainstem abnormalities in Ptf1a−/− mice are mediated by a dramatic cell-fate misspecification in rhombomeres 2–7, which results in the production of supernumerary viscerosensory and somatosensory neurons of the Lmx1b lineage at the expense of Pax2+ GABAergic viscerosensory and somatosensory neurons, and inferior olivary neurons. Our data identify Ptf1a as a major regulator of cell-fate specification decisions in the developing brainstem, and as a previously unrecognized developmental regulator of both viscerosensory and somatosensory brainstem nuclei. SIGNIFICANCE STATEMENT Cell-fate specification decisions are critical for normal CNS development. Although extensively studied in the cerebellum and spinal cord, the mechanisms mediating cell-fate decisions in the brainstem, which regulates a wide range of processes vital to the organism, remain largely unknown. Here we identified mouse Ptf1a as a novel regulator of cell-fate decisions during both early and late brainstem neurogenesis, which are critical for proper

  4. Highly variable individual donor cell fates characterize robust horizontal gene transfer of an integrative and conjugative element.

    Science.gov (United States)

    Delavat, François; Mitri, Sara; Pelet, Serge; van der Meer, Jan Roelof

    2016-06-14

    Horizontal gene transfer is an important evolutionary mechanism for bacterial adaptation. However, given the typical low transfer frequencies in a bacterial population, little is known about the fate and interplay of donor cells and the mobilized DNA during transfer. Here we study transfer of an integrative and conjugative element (ICE) among individual live bacterial cells. ICEs are widely distributed mobile DNA elements that are different than plasmids because they reside silent in the host chromosome and are maintained through vertical descent. Occasionally, ICEs become active, excise, and transmit their DNA to a new recipient, where it is reintegrated. We develop a fluorescent tool to differentiate excision, transfer, and reintegration of a model ICE named ICEclc (for carrying the clc genes for chlorocatechol metabolism) among single Pseudomonas cells by using time-lapse microscopy. We find that ICEclc activation is initiated in stationary phase cells, but excision and transfer predominantly occur only when such cells have been presented with new nutrients. Donors with activated ICE develop a number of different states, characterized by reduced cell division rates or growth arrest, persistence, or lysis, concomitant with ICE excision, and likely, ICE loss or replication. The donor cell state transitions can be described by using a stochastic model, which predicts that ICE fitness is optimal at low initiation rates in stationary phase. Despite highly variable donor cell fates, ICE transfer is remarkably robust overall, with 75% success after excision. Our results help to better understand ICE behavior and shed a new light on bacterial cellular differentiation during horizontal gene transfer.

  5. Aging alters bone-fat reciprocity by shifting in vivo mesenchymal precursor cell fate towards an adipogenic lineage.

    Science.gov (United States)

    Singh, Lakshman; Brennan, Tracy A; Russell, Elizabeth; Kim, Jung-Hoon; Chen, Qijun; Brad Johnson, F; Pignolo, Robert J

    2016-04-01

    Bone marrow derived mesenchymal progenitor cells (MPCs) play an important role in bone homeostasis. Age-related changes occur in bone resulting in a decrease in bone density and a relative increase in adipocity. Although in vitro studies suggest the existence of an age-related lineage switch between osteogenic and adipogenic fates, stem cell and microenvironmental contributions to this process have not been elucidated in vivo. In order to study the effects of MPC and microenvironmental aging on functional engraftment and lineage switching, transplantation studies were performed under non-myeloablative conditions in old recipients, with donor MPCs derived from young and old green fluorescent protein (GFP) transgenic mice. Robust engraftment by young MPCs or their progeny was observed in the marrow, bone-lining region and in the matrix of young recipients; however, significantly lower engraftment was seen at the same sites in old recipients transplanted with old MPCs. Differentiation of transplanted MPCs strongly favored adipogenesis over osteogenesis in old recipients irrespective of MPC donor age, suggesting that microenvironmental alterations that occur with in vivo aging are predominately responsible for MPC lineage switching. These data indicate that aging alters bone-fat reciprocity and differentiation of mesenchymal progenitors towards an adipogenic fate. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Opposing regulation of PROX1 by interleukin-3 receptor and NOTCH directs differential host cell fate reprogramming by Kaposi sarcoma herpes virus.

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    Jaehyuk Yoo

    Full Text Available Lymphatic endothelial cells (LECs are differentiated from blood vascular endothelial cells (BECs during embryogenesis and this physiological cell fate specification is controlled by PROX1, the master regulator for lymphatic development. When Kaposi sarcoma herpes virus (KSHV infects host cells, it activates the otherwise silenced embryonic endothelial differentiation program and reprograms their cell fates. Interestingly, previous studies demonstrated that KSHV drives BECs to acquire a partial lymphatic phenotype by upregulating PROX1 (forward reprogramming, but stimulates LECs to regain some BEC-signature genes by downregulating PROX1 (reverse reprogramming. Despite the significance of this KSHV-induced bidirectional cell fate reprogramming in KS pathogenesis, its underlying molecular mechanism remains undefined. Here, we report that IL3 receptor alpha (IL3Rα and NOTCH play integral roles in the host cell type-specific regulation of PROX1 by KSHV. In BECs, KSHV upregulates IL3Rα and phosphorylates STAT5, which binds and activates the PROX1 promoter. In LECs, however, PROX1 was rather downregulated by KSHV-induced NOTCH signal via HEY1, which binds and represses the PROX1 promoter. Moreover, PROX1 was found to be required to maintain HEY1 expression in LECs, establishing a reciprocal regulation between PROX1 and HEY1. Upon co-activation of IL3Rα and NOTCH, PROX1 was upregulated in BECs, but downregulated in LECs. Together, our study provides the molecular mechanism underlying the cell type-specific endothelial fate reprogramming by KSHV.

  7. Mir-29b Mediates the Neural Tube versus Neural Crest Fate Decision during Embryonic Stem Cell Neural Differentiation.

    Science.gov (United States)

    Xi, Jiajie; Wu, Yukang; Li, Guoping; Ma, Li; Feng, Ke; Guo, Xudong; Jia, Wenwen; Wang, Guiying; Yang, Guang; Li, Ping; Kang, Jiuhong

    2017-08-08

    During gastrulation, the neuroectoderm cells form the neural tube and neural crest. The nervous system contains significantly more microRNAs than other tissues, but the role of microRNAs in controlling the differentiation of neuroectodermal cells into neural tube epithelial (NTE) cells and neural crest cells (NCCs) remains unknown. Using embryonic stem cell (ESC) neural differentiation systems, we found that miR-29b was upregulated in NTE cells and downregulated in NCCs. MiR-29b promoted the differentiation of ESCs into NTE cells and inhibited their differentiation into NCCs. Accordingly, the inhibition of miR-29b significantly inhibited the differentiation of NTE cells. A mechanistic study revealed that miR-29b targets DNA methyltransferase 3a (Dnmt3a) to regulate neural differentiation. Moreover, miR-29b mediated the function of Pou3f1, a critical neural transcription factor. Therefore, our study showed that the Pou3f1-miR-29b-Dnmt3a regulatory axis was active at the initial stage of neural differentiation and regulated the determination of cell fate. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Restoration of p53 Expression in Human Cancer Cell Lines Upregulates the Expression of Notch1: Implications for Cancer Cell Fate Determination after Genotoxic Stress

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    Fatouma Alimirah

    2007-05-01

    Full Text Available Following genotoxic stress, transcriptional activation of target genes by p53 tumor suppressor is critical in cell fate determination. Here we report that the restoration of p53 function in human cancer cell lines that are deficient in p53 function upregulated the expression of Notch1. Interestingly, the expression of wild-type p53 in human prostate and breast cancer cell lines correlated well with increased expression of Notch1. Furthermore, knockdown of p53 expression in cancer cells that express wild-type p53 resulted in reduced expression of Notch1. Importantly, genotoxic stress to cancer cells that resulted in activation of p53 also upregulated the expression of Notch1. Moreover, p53mediated induction of Notch1 expression was associated with stimulation of the activity of Notch-responsive reporters. Notably, p53 differentially regulated the expression of Notch family members: expression of Notch2 and Notch4 was not induced by p53. Significantly, treatment of cells with gamma secretase inhibitor, an inhibitor of Notch signaling, increased susceptibility to apoptosis in response to genotoxic stress. Together, our observations suggest that p53mediated upregulation of Notch1 expression in human cancer cell lines contributes to cell fate determination after genotoxic stress.

  9. Imaging long-term fate of intramyocardially implanted mesenchymal stem cells in a porcine myocardial infarction model.

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    Emerson C Perin

    Full Text Available The long-term fate of stem cells after intramyocardial delivery is unknown. We used noninvasive, repetitive PET/CT imaging with [(18F]FEAU to monitor the long-term (up to 5 months spatial-temporal dynamics of MSCs retrovirally transduced with the sr39HSV1-tk gene (sr39HSV1-tk-MSC and implanted intramyocardially in pigs with induced acute myocardial infarction. Repetitive [(18F]FEAU PET/CT revealed a biphasic pattern of sr39HSV1-tk-MSC dynamics; cell proliferation peaked at 33-35 days after injection, in periinfarct regions and the major cardiac lymphatic vessels and lymph nodes. The sr39HSV1-tk-MSC-associated [(18F]FEAU signals gradually decreased thereafter. Cardiac lymphography studies using PG-Gd-NIRF813 contrast for MRI and near-infrared fluorescence imaging showed rapid clearance of the contrast from the site of intramyocardial injection through the subepicardial lymphatic network into the lymphatic vessels and periaortic lymph nodes. Immunohistochemical analysis of cardiac tissue obtained at 35 and 150 days demonstrated several types of sr39HSV1-tk expressing cells, including fibro-myoblasts, lymphovascular cells, and microvascular and arterial endothelium. In summary, this study demonstrated the feasibility and sensitivity of [(18F]FEAU PET/CT imaging for long-term, in-vivo monitoring (up to 5 months of the fate of intramyocardially injected sr39HSV1-tk-MSC cells. Intramyocardially transplanted MSCs appear to integrate into the lymphatic endothelium and may help improve myocardial lymphatic system function after MI.

  10. Imaging long-term fate of intramyocardially implanted mesenchymal stem cells in a porcine myocardial infarction model.

    Science.gov (United States)

    Perin, Emerson C; Tian, Mei; Marini, Frank C; Silva, Guilherme V; Zheng, Yi; Baimbridge, Fred; Quan, Xin; Fernandes, Marlos R; Gahremanpour, Amir; Young, Daniel; Paolillo, Vincenzo; Mukhopadhyay, Uday; Borne, Agatha T; Uthamanthil, Rajesh; Brammer, David; Jackson, James; Decker, William K; Najjar, Amer M; Thomas, Michael W; Volgin, Andrei; Rabinovich, Brian; Soghomonyan, Suren; Jeong, Hwan-Jeong; Rios, Jesse M; Steiner, David; Robinson, Simon; Mawlawi, Osama; Pan, Tinsu; Stafford, Jason; Kundra, Vikas; Li, Chun; Alauddin, Mian M; Willerson, James T; Shpall, Elizabeth; Gelovani, Juri G

    2011-01-01

    The long-term fate of stem cells after intramyocardial delivery is unknown. We used noninvasive, repetitive PET/CT imaging with [(18)F]FEAU to monitor the long-term (up to 5 months) spatial-temporal dynamics of MSCs retrovirally transduced with the sr39HSV1-tk gene (sr39HSV1-tk-MSC) and implanted intramyocardially in pigs with induced acute myocardial infarction. Repetitive [(18)F]FEAU PET/CT revealed a biphasic pattern of sr39HSV1-tk-MSC dynamics; cell proliferation peaked at 33-35 days after injection, in periinfarct regions and the major cardiac lymphatic vessels and lymph nodes. The sr39HSV1-tk-MSC-associated [(18)F]FEAU signals gradually decreased thereafter. Cardiac lymphography studies using PG-Gd-NIRF813 contrast for MRI and near-infrared fluorescence imaging showed rapid clearance of the contrast from the site of intramyocardial injection through the subepicardial lymphatic network into the lymphatic vessels and periaortic lymph nodes. Immunohistochemical analysis of cardiac tissue obtained at 35 and 150 days demonstrated several types of sr39HSV1-tk expressing cells, including fibro-myoblasts, lymphovascular cells, and microvascular and arterial endothelium. In summary, this study demonstrated the feasibility and sensitivity of [(18)F]FEAU PET/CT imaging for long-term, in-vivo monitoring (up to 5 months) of the fate of intramyocardially injected sr39HSV1-tk-MSC cells. Intramyocardially transplanted MSCs appear to integrate into the lymphatic endothelium and may help improve myocardial lymphatic system function after MI.

  11. Control of flowering and cell fate by LIF2, an RNA binding partner of the polycomb complex component LHP1.

    Directory of Open Access Journals (Sweden)

    David Latrasse

    Full Text Available Polycomb Repressive Complexes (PRC modulate the epigenetic status of key cell fate and developmental regulators in eukaryotes. The chromo domain protein like heterochromatin protein1 (LHP1 is a subunit of a plant PRC1-like complex in Arabidopsis thaliana and recognizes histone H3 lysine 27 trimethylation, a silencing epigenetic mark deposited by the PRC2 complex. We have identified and studied an LHP1-Interacting Factor2 (LIF2. LIF2 protein has RNA recognition motifs and belongs to the large hnRNP protein family, which is involved in RNA processing. LIF2 interacts in vivo, in the cell nucleus, with the LHP1 chromo shadow domain. Expression of LIF2 was detected predominantly in vascular and meristematic tissues. Loss-of-function of LIF2 modifies flowering time, floral developmental homeostasis and gynoecium growth determination. lif2 ovaries have indeterminate growth and produce ectopic inflorescences with severely affected flowers showing proliferation of ectopic stigmatic papillae and ovules in short-day conditions. To look at how LIF2 acts relative to LHP1, we conducted transcriptome analyses in lif2 and lhp1 and identified a common set of deregulated genes, which showed significant enrichment in stress-response genes. By comparing expression of LHP1 targets in lif2, lhp1 and lif2 lhp1 mutants we showed that LIF2 can either antagonize or act with LHP1. Interestingly, repression of the FLC floral transcriptional regulator in lif2 mutant is accompanied by an increase in H3K27 trimethylation at the locus, without any change in LHP1 binding, suggesting that LHP1 is targeted independently from LIF2 and that LHP1 binding does not strictly correlate with gene expression. LIF2, involved in cell identity and cell fate decision, may modulate the activity of LHP1 at specific loci, during specific developmental windows or in response to environmental cues that control cell fate determination. These results highlight a novel link between plant RNA

  12. High-definition mapping of retroviral integration sites defines the fate of allogeneic T cells after donor lymphocyte infusion.

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    Claudia Cattoglio

    2010-12-01

    Full Text Available The infusion of donor lymphocytes transduced with a retroviral vector expressing the HSV-TK suicide gene in patients undergoing hematopoietic stem cell transplantation for leukemia/lymphoma promotes immune reconstitution and prevents infections and graft-versus-host disease. Analysis of the clonal dynamics of genetically modified lymphocytes in vivo is of crucial importance to understand the potential genotoxic risk of this therapeutic approach. We used linear amplification-mediated PCR and pyrosequencing to build a genome-wide, high-definition map of retroviral integration sites in the genome of peripheral blood T cells from two different donors and used gene expression profiling and bioinformatics to associate integration clusters to transcriptional activity and to genetic and epigenetic features of the T cell genome. Comparison with matched random controls and with integrations obtained from CD34(+ hematopoietic stem/progenitor cells showed that integration clusters occur within chromatin regions bearing epigenetic marks associated with active promoters and regulatory elements in a cell-specific fashion. Analysis of integration sites in T cells obtained ex vivo two months after infusion showed no evidence of integration-related clonal expansion or dominance, but rather loss of cells harboring integration events interfering with RNA post-transcriptional processing. The study shows that high-definition maps of retroviral integration sites are a powerful tool to analyze the fate of genetically modified T cells in patients and the biological consequences of retroviral transduction.

  13. Scaffold composition affects cytoskeleton organization, cell-matrix interaction and the cellular fate of human mesenchymal stem cells upon chondrogenic differentiation.

    Science.gov (United States)

    Li, Yuk Yin; Choy, Tze Hang; Ho, Fu Chak; Chan, Pui Barbara

    2015-06-01

    The stem cell niche, or microenvironment, consists of soluble, matrix, cell and mechanical factors that together determine the cellular fates and/or differentiation patterns of stem cells. Collagen and glycosaminoglycans (GAGs) are important scaffolding materials that can mimic the natural matrix niche. Here, we hypothesize that imposing changes in the scaffold composition or, more specifically, incorporating GAGs into the collagen meshwork, will affect the morphology, cytoskeletal organization and integrin expression profiles, and hence the fate of human mesenchymal stem cells (MSCs) upon the induction of differentiation. Using chondrogenesis as an example, we microencapsulated MSCs in three scaffold systems that had varying matrix compositions: collagen alone (C), aminated collagen (AC) and aminated collagen with GAGs (ACG). We then induced the MSCs to differentiate toward a chondrogenic lineage, after which, we characterized the cell viability and morphology, as well as the level of cytoskeletal organization and the integrin expression profile. We also studied the fate of the MSCs by evaluating the major chondrogenic markers at both the gene and protein level. In C, MSC chondrogenesis was successfully induced and MSCs that spread in the scaffolds had a clear actin cytoskeleton; they expressed integrin α2β1, α5 and αv; promoted sox9 nuclear localization transcription activation; and upregulated the expression of chondrogenic matrix markers. In AC, MSC chondrogenesis was completely inhibited but the scaffold still supported cell survival. The MSCs did not spread and they had no actin cytoskeleton; did not express integrin α2 or αv; they failed to differentiate into chondrogenic lineage cells even on chemical induction; and there was little colocalization or functional interaction between integrin α5 and fibronectin. In ACG, although the MSCs did not express integrin α2, they did express integrin αv and there was strong co-localization and hence functional

  14. Notch-mediated post-translational control of Ngn3 protein stability regulates pancreatic patterning and cell fate commitment

    DEFF Research Database (Denmark)

    Qu, Xiaoling; Afelik, Solomon; Jensen, Jan Nygaard

    2013-01-01

    of ducts. On one hand, Ngn3 cell-intrinsically activates endocrine target genes; on the other, Ngn3 cell-extrinsically promotes lateral signaling via the Dll1>Notch>Hes1 pathway which substantially limits its ability to sustain endocrine formation. Prior to endocrine commitment, the Ngn3-mediated...... activation of the Notch>Hes1 pathway impacts formation of the trunk domain in the pancreas causing multipotent progenitors to lose acinar, while gaining endocrine and ductal, competence. The subsequent selection of fate from such bipotential progenitors is then governed by lateral inhibition, where Notch>Hes...... protein stabilization in the normal mouse pancreas explants. We conclude that the mutually exclusive expression pattern of Ngn3/Hes1 proteins in the mammalian pancreas is partially controlled through Notch-mediated post-translational regulation and we demonstrate that the formation of insulin...

  15. Unraveling the mechanistic effects of electric field stimulation towards directing stem cell fate and function: A tissue engineering perspective.

    Science.gov (United States)

    Thrivikraman, Greeshma; Boda, Sunil Kumar; Basu, Bikramjit

    2018-01-01

    Electric field (EF) stimulation can play a vital role in eliciting appropriate stem cell response. Such an approach is recently being established to guide stem cell differentiation through osteogenesis/neurogenesis/cardiomyogenesis. Despite significant recent efforts, the biophysical mechanisms by which stem cells sense, interpret and transform electrical cues into biochemical and biological signals still remain unclear. The present review critically analyses the variety of EF stimulation approaches that can be employed to evoke appropriate stem cell response and also makes an attempt to summarize the underlying concepts of this notion, placing special emphasis on stem cell based tissue engineering and regenerative medicine. This review also discusses the major signaling pathways and cellular responses that are elicited by electric stimulation, including the participation of reactive oxygen species and heat shock proteins, modulation of intracellular calcium ion concentration, ATP production and numerous other events involving the clustering or reassembling of cell surface receptors, cytoskeletal remodeling and so on. The specific advantages of using external electric stimulation in different modalities to regulate stem cell fate processes are highlighted with explicit examples, in vitro and in vivo. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Type I and Type II Interferon Coordinately Regulate Suppressive Dendritic Cell Fate and Function during Viral Persistence.

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    Cameron R Cunningham

    2016-01-01

    Full Text Available Persistent viral infections are simultaneously associated with chronic inflammation and highly potent immunosuppressive programs mediated by IL-10 and PDL1 that attenuate antiviral T cell responses. Inhibiting these suppressive signals enhances T cell function to control persistent infection; yet, the underlying signals and mechanisms that program immunosuppressive cell fates and functions are not well understood. Herein, we use lymphocytic choriomeningitis virus infection (LCMV to demonstrate that the induction and functional programming of immunosuppressive dendritic cells (DCs during viral persistence are separable mechanisms programmed by factors primarily considered pro-inflammatory. IFNγ first induces the de novo development of naive monocytes into DCs with immunosuppressive potential. Type I interferon (IFN-I then directly targets these newly generated DCs to program their potent T cell immunosuppressive functions while simultaneously inhibiting conventional DCs with T cell stimulating capacity. These mechanisms of monocyte conversion are constant throughout persistent infection, establishing a system to continuously interpret and shape the immunologic environment. MyD88 signaling was required for the differentiation of suppressive DCs, whereas inhibition of stimulatory DCs was dependent on MAVS signaling, demonstrating a bifurcation in the pathogen recognition pathways that promote distinct elements of IFN-I mediated immunosuppression. Further, a similar suppressive DC origin and differentiation was also observed in Mycobacterium tuberculosis infection, HIV infection and cancer. Ultimately, targeting the underlying mechanisms that induce immunosuppression could simultaneously prevent multiple suppressive signals to further restore T cell function and control persistent infections.

  17. Adult interfollicular tumour-initiating cells are reprogrammed into an embryonic hair follicle progenitor-like fate during basal cell carcinoma initiation.

    Science.gov (United States)

    Youssef, Khalil Kass; Lapouge, Gaëlle; Bouvrée, Karine; Rorive, Sandrine; Brohée, Sylvain; Appelstein, Ornella; Larsimont, Jean-Christophe; Sukumaran, Vijayakumar; Van de Sande, Bram; Pucci, Doriana; Dekoninck, Sophie; Berthe, Jean-Valery; Aerts, Stein; Salmon, Isabelle; del Marmol, Véronique; Blanpain, Cédric

    2012-12-01

    Basal cell carcinoma, the most frequent human skin cancer, arises from activating hedgehog (HH) pathway mutations; however, little is known about the temporal changes that occur in tumour-initiating cells from the first oncogenic hit to the development of invasive cancer. Using an inducible mouse model enabling the expression of a constitutively active Smoothened mutant (SmoM2) in the adult epidermis, we carried out transcriptional profiling of SmoM2-expressing cells at different times during cancer initiation. We found that tumour-initiating cells are massively reprogrammed into a fate resembling that of embryonic hair follicle progenitors (EHFPs). Wnt/ β-catenin signalling was very rapidly activated following SmoM2 expression in adult epidermis and coincided with the expression of EHFP markers. Deletion of β-catenin in adult SmoM2-expressing cells prevents EHFP reprogramming and tumour initiation. Finally, human basal cell carcinomas also express genes of the Wnt signalling and EHFP signatures.

  18. Engineering hyaluronic acid hydrogel degradation to control cellular interactions and adult stem cell fate in 3D

    Science.gov (United States)

    Khetan, Sudhir

    The design and implementation of extracellular matrix (ECM)-mimetic hydrogels for tissue engineering (TE) applications requires an intensive understanding of cell-material interactions, including matrix remodeling and stem cell differentiation. However, the influence of microenvironmental cues, e.g., matrix biodegradability, on cell behavior in vitro has not been well studied in the case of direct cell encapsulation within 3-dimensional (3D) hydrogels. To address these issues, a facile sequential crosslinking technique was developed that provides spatial and temporal control of 3D hydrogel degradability to investigate the importance of material design on cell behavior. Specifically, hydrogels were synthesized from hyaluronic acid (HA) macromers in a sequential process: (1) a primary Michael-type addition crosslinking using cell adhesive and matrix metalloprotease (MMP)-degradable oligopeptides to consume a portion of total reactive groups and resulting in "-UV" hydrogels permissive to cell-mediated degradation, followed by (2) a secondary, light initiated free-radical crosslinking to consume remaining reactive groups and "switch" the network to a non-degradable structure ("+UV") via the addition of non-degradable kinetic chains. Using this approach, we demonstrated control of encapsulated hMSC spreading by varying the crosslink type (i.e., the relative hydrogel biodegradability), including with spatial control. Upon incubation with bipotential soluble differentiation factors, these same degradation-mediated spreading cues resulted in an hMSC differentiation fate switch within -UV versus +UV environments. Follow-up studies demonstrated that degradation-mediated traction generation, rather than matrix mechanics or cell morphology, is the critical biophysical signal determining hMSC fate. Sequentially crosslinked HA hydrogels were also studied for the capacity to support remodeling by in vivo and ex vivo tissues, including with spatial control, toward tissue

  19. Stem cells: a new choice for diabetes therapy

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    Yi-ming MU

    2015-07-01

    Full Text Available The failure of pancreatic islet beta cells and insulin resistance are the main mechanism of the occurrence and development of diabetes. The current anti-diabetic drugs, which do not focus on the key pathogenesis of diabetes mellitus, can only eliminate or alleviate the symptoms, delay the progression of the disease, but can not cure the disease fundamentally. Stem cells, which have unique biological characteristics, extremely strong self-renewal ability, multi direction differentiation potential, and secretion of a variety of cytokines, have become a star in the diabetes treatment. Basic researches showed that stem cells may ameliorate hyperglycemia persistently and stably by improving the function of islet beta cells and increasing insulin sensitivity of peripheral target tissue. Some small-sample clinical trials have demonstrated its effectiveness and safety, while prospective largesample, randomized, placebo-controlled clinical trials may provide more evidence on its efficacy and safety, and pave the way for the clinical use of stem cell therapy for diabetes mellitus. DOI: 10.11855/j.issn.0577-7402.2015.07.01

  20. Transcription Factor Bcl11b Controls Effector and Memory CD8 T cell Fate Decision and Function During Poxvirus Infection

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    Georges Abboud

    2016-10-01

    Full Text Available CD8+ T cells play an important role in host resistance to many viral infections, but the underlying transcriptional mechanisms governing their differentiation and functionality remain poorly defined. By using a highly virulent systemic and respiratory poxvirus infection in mice, we show that the transcription factor Bcl11b provides a dual trigger that sustains the clonal expansion of virus-specific effector CD8+ T cells, while simultaneously suppressing the expression of surface markers associated with short-lived effector cell (SLEC differentiation. Additionally, we demonstrate that Bcl11b supports the acquisition of memory precursor effector cell (MPEC phenotype, and thus its absence causes near complete loss of lymphoid and lung-resident memory cells. Interestingly, despite having normal levels of T-bet and Eomesodermin, Bcl11b-deficient CD8+ T cells failed to execute effector differentiation needed for anti-viral cytokine production and degranulation, suggesting a non-redundant role of Bcl11b in regulation of this program. Thus, Bcl11b is a critical player in fate decision of SLECs and MPECs, as well as effector function and memory formation.

  1. Dose-dependent functions of fibroblast growth factor 9 regulate the fate of murine XY primordial germ cells.

    Science.gov (United States)

    Ulu, Ferhat; Kim, Sung-Min; Yokoyama, Toshifumi; Yamazaki, Yukiko

    2017-01-01

    Male differentiation of primordial germ cells (PGCs) is initiated by the inhibition of entry into meiosis and exposure to male-inducing factor(s), which are regulated by somatic elements of the developing gonad. Fibroblast growth factor 9 (FGF9) produced by pre-Sertoli cells is essential for male gonadal differentiation and also contributes to survival and male differentiation of XY PGCs. However, it is not clear how FGF9 regulates PGC fate. Using a PGC culture system, we identified dose-dependent, fate-determining functions of FGF9 in XY PGCs. Treatment with low levels of FGF9 (0.2 ng/ml) increased expression of male-specific Dnmt3L and Nanos2 in XY PGCs. Conversely, treatment with high levels of FGF9 (25 ng/ml) suppressed male-specific gene expression and stimulated proliferation of XY PGCs. Western blotting showed that low FGF9 treatment enhanced p38 MAPK (mitogen-activated protein kinase) phosphorylation in the same cells. In contrast, high FGF9 treatment significantly stimulated the ERK (extracellular signal-regulated kinase)1/2 signaling pathway in XY PGCs. We investigated the relationship between the ERK1/2 signaling pathway stimulated by high FGF9 and regulation of PGC proliferation. An ERK1/2 inhibitor (U0126) suppressed the PGC proliferation that would otherwise be stimulated by high FGF9 treatment, and increased Nanos2 expression in XY PGCs. Conversely, a p38 MAPK inhibitor (SB202190) significantly suppressed Nanos2 expression that would otherwise be stimulated by low FGF9 in XY PGCs. Taken together, our results suggest that stage-specific expression of FGF9 in XY gonads regulates the balance between proliferation and differentiation of XY PGCs in a dose-dependent manner. © The Author 2016. Published by Oxford University Press on behalf of Society for the Study of Reproduction.

  2. The homeodomain transcription factor PITX2 is required for specifying correct cell fates and establishing angiogenic privilege in the developing cornea.

    Science.gov (United States)

    Gage, Philip J; Kuang, Chen; Zacharias, Amanda L

    2014-11-01

    Correct specification of cell lineages and establishing angiogenic privilege within the developing cornea are essential for normal vision but the mechanisms controlling these processes are poorly understood. We show that the homeodomain transcription factor PItX2 is expressed in mesenchymal cells of the developing and mature cornea and use a temporal gene knockout approach to demonstrate that PITX2 is required for corneal morphogenesis and the specification of cell fates within the surface ectoderm and mesenchymal primordia. PITX2 is also required to establish angiogenic privilege in the developing cornea. Further, the expression of Dkk2 and suppression of canonical Wnt signaling activity levels are key mechanisms by which PITX2 specifies ocular surface ectoderm as cornea. In contrast, specifying the underlying mesenchyme to corneal fates and establishing angiogenic privilege in the cornea are less sensitive to DKK2 activity. Finally, the cellular expression patterns of FOXC2, PITX1, and BARX2 in Pitx2 and Dkk2 mutants suggest that these transcription factors may be involved in specifying cell fate and establishing angiogenic privilege within the corneal mesenchyme. However, they are unlikely to play a role in specifying cell fate within the corneal ectoderm. Together, these data provide important insights into the mechanisms regulating cornea development. Copyright © 2014 Wiley Periodicals, Inc.

  3. Marked induction of the helix-loop-helix protein Id3 promotes the gammadelta T cell fate and renders their functional maturation Notch independent

    DEFF Research Database (Denmark)

    Lauritsen, Jens Peter Holst; Wong, Gladys W; Lee, Sang-Yun

    2009-01-01

    alphabeta and gammadelta T cells arise from a common thymocyte progenitor during development in the thymus. Emerging evidence suggests that the pre-T cell receptor (pre-TCR) and gammadelta T cell receptor (gammadeltaTCR) play instructional roles in specifying the alphabeta and gammadelta T...... IFNgamma-producing effectors. Taken together, these findings identify Id3 as a central player that controls both adoption of the gammadelta fate and its maturation in the thymus....

  4. Fate mapping for activation-induced cytidine deaminase (AID marks non-lymphoid cells during mouse development.

    Directory of Open Access Journals (Sweden)

    Philipp C Rommel

    Full Text Available The Aicda gene encodes Activation-Induced cytidine Deaminase (AID, an enzyme essential for remodeling antibody genes in mature B lymphocytes. AID is also responsible for DNA damage at oncogenes, leading to their mutation and cancer-associated chromosome translocation in lymphoma. We used fate mapping and AID(GFP reporter mice to determine if AID expression in the mouse extends beyond lymphocytes. We discovered that AID(cre tags a small fraction of non-lymphoid cells starting at 10.5 days post conception (dpc, and that AID(GFP+ cells are detectable at dpc 11.5 and 12.5. Embryonic cells are tagged by AID(cre in the submandibular region, where conditional deletion of the tumor suppressor PTEN causes squamous papillomas. AID(cre also tags non-lymphoid cells in the embryonic central nervous system. Finally, in the adult mouse brain, AID(cre marks a small fraction of diverse neurons and distinct neuronal populations, including pyramidal cells in cortical layer IV.

  5. Focal adhesion kinase protein regulates Wnt3a gene expression to control cell fate specification in the developing neural plate

    Science.gov (United States)

    Fonar, Yuri; Gutkovich, Yoni E.; Root, Heather; Malyarova, Anastasia; Aamar, Emil; Golubovskaya, Vita M.; Elias, Sarah; Elkouby, Yaniv M.; Frank, Dale

    2011-01-01

    Focal adhesion kinase (FAK) is a cytoplasmic tyrosine kinase protein localized to regions called focal adhesions, which are contact points between cells and the extracellular matrix. FAK protein acts as a scaffold to transfer adhesion-dependent and growth factor signals into the cell. Increased FAK expression is linked to aggressive metastatic and invasive tumors. However, little is known about its normal embryonic function. FAK protein knockdown during early Xenopus laevis development anteriorizes the embryo. Morphant embryos express increased levels of anterior neural markers, with reciprocally reduced posterior neural marker expression. Posterior neural plate folding and convergence-extension is also inhibited. This anteriorized phenotype resembles that of embryos knocked down zygotically for canonical Wnt signaling. FAK and Wnt3a genes are both expressed in the neural plate, and Wnt3a expression is FAK dependent. Ectopic Wnt expression rescues this FAK morphant anteriorized phenotype. Wnt3a thus acts downstream of FAK to balance anterior–posterior cell fate specification in the developing neural plate. Wnt3a gene expression is also FAK dependent in human breast cancer cells, suggesting that this FAK–Wnt linkage is highly conserved. This unique observation connects the FAK- and Wnt-signaling pathways, both of which act to promote cancer when aberrantly activated in mammalian cells. PMID:21551070

  6. p53 Modulates the Fate of Cardiac Progenitor Cells Ex Vivo and in the Diabetic Heart In Vivo

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    Ramaswamy Kannappan

    2017-02-01

    Full Text Available p53 is an important modulator of stem cell fate, but its role in cardiac progenitor cells (CPCs is unknown. Here, we tested the effects of a single extra-copy of p53 on the function of CPCs in the presence of oxidative stress mediated by doxorubicin in vitro and type-1 diabetes in vivo. CPCs were obtained from super-p53 transgenic mice (p53-tg, in which the additional allele is regulated in a manner similar to the endogenous protein. Old CPCs with increased p53 dosage showed a superior ability to sustain oxidative stress, repair DNA damage and restore cell division. With doxorubicin, a larger fraction of CPCs carrying an extra-copy of the p53 allele recruited γH2A.X reestablishing DNA integrity. Enhanced p53 expression resulted in a superior tolerance to oxidative stress in vivo by providing CPCs with defense mechanisms necessary to survive in the milieu of the diabetic heart; they engrafted in regions of tissue injury and in three days acquired the cardiomyocyte phenotype. The biological advantage provided by the increased dosage of p53 in CPCs suggests that this genetic strategy may be translated to humans to increase cellular engraftment and growth, critical determinants of successful cell therapy for the failing heart.

  7. Metabolic fate of glucose and candidate signaling and excess-fuel detoxification pathways in pancreatic β-cells.

    Science.gov (United States)

    Mugabo, Yves; Zhao, Shangang; Lamontagne, Julien; Al-Mass, Anfal; Peyot, Marie-Line; Corkey, Barbara E; Joly, Erik; Madiraju, S R Murthy; Prentki, Marc

    2017-05-05

    Glucose metabolism promotes insulin secretion in β-cells via metabolic coupling factors that are incompletely defined. Moreover, chronically elevated glucose causes β-cell dysfunction, but little is known about how cells handle excess fuels to avoid toxicity. Here we sought to determine which among the candidate pathways and coupling factors best correlates with glucose-stimulated insulin secretion (GSIS), define the fate of glucose in the β-cell, and identify pathways possibly involved in excess-fuel detoxification. We exposed isolated rat islets for 1 h to increasing glucose concentrations and measured various pathways and metabolites. Glucose oxidation, oxygen consumption, and ATP production correlated well with GSIS and saturated at 16 mm glucose. However, glucose utilization, glycerol release, triglyceride and glycogen contents, free fatty acid (FFA) content and release, and cholesterol and cholesterol esters increased linearly up to 25 mm glucose. Besides being oxidized, glucose was mainly metabolized via glycerol production and release and lipid synthesis (particularly FFA, triglycerides, and cholesterol), whereas glycogen production was comparatively low. Using targeted metabolomics in INS-1(832/13) cells, we found that several metabolites correlated well with GSIS, in particular some Krebs cycle intermediates, malonyl-CoA, and lower ADP levels. Glucose dose-dependently increased the dihydroxyacetone phosphate/glycerol 3-phosphate ratio in INS-1(832/13) cells, indicating a more oxidized state of NAD in the cytosol upon glucose stimulation. Overall, the data support a role for accelerated oxidative mitochondrial metabolism, anaplerosis, and malonyl-CoA/lipid signaling in β-cell metabolic signaling and suggest that a decrease in ADP levels is important in GSIS. The results also suggest that excess-fuel detoxification pathways in β-cells possibly comprise glycerol and FFA formation and release extracellularly and the diversion of glucose carbons to

  8. Ascorbic acid alters cell fate commitment of human neural progenitors in a WNT/β-catenin/ROS signaling dependent manner.

    Science.gov (United States)

    Rharass, Tareck; Lantow, Margareta; Gbankoto, Adam; Weiss, Dieter G; Panáková, Daniela; Lucas, Stéphanie

    2017-10-16

    Improving the neuronal yield from in vitro cultivated neural progenitor cells (NPCs) is an essential challenge in transplantation therapy in neurological disorders. In this regard, Ascorbic acid (AA) is widely used to expand neurogenesis from NPCs in cultures although the mechanisms of its action remain unclear. Neurogenesis from NPCs is regulated by the redox-sensitive WNT/β-catenin signaling pathway. We therefore aimed to investigate how AA interacts with this pathway and potentiates neurogenesis. Effects of 200 μM AA were compared with the pro-neurogenic reagent and WNT/β-catenin signaling agonist lithium chloride (LiCl), and molecules with antioxidant activities i.e. N-acetyl-L-cysteine (NAC) and ruthenium red (RuR), in differentiating neural progenitor ReNcell VM cells. Cells were supplemented with reagents for two periods of treatment: a full period encompassing the whole differentiation process versus an early short period that is restricted to the cell fate commitment stage. Intracellular redox balance and reactive oxygen species (ROS) metabolism were examined by flow cytometry using redox and ROS sensors. Confocal microscopy was performed to assess cell viability, neuronal yield, and levels of two proteins: Nucleoredoxin (NXN) and the WNT/β-catenin signaling component Dishevelled 2 (DVL2). TUBB3 and MYC gene responses were evaluated by quantitative real-time PCR. DVL2-NXN complex dissociation was measured by fluorescence resonance energy transfer (FRET). In contrast to NAC which predictably exhibited an antioxidant effect, AA treatment enhanced ROS metabolism with no cytotoxic induction. Both drugs altered ROS levels only at the early stage of the differentiation as no changes were held beyond the neuronal fate commitment stage. FRET studies showed that AA treatment accelerated the redox-dependent release of the initial pool of DVL2 from its sequestration by NXN, while RuR treatment hampered the dissociation of the two proteins. Accordingly, AA

  9. Sexual Fate Change of XX Germ Cells Caused by the Deletion of SMAD4 and STRA8 Independent of Somatic Sex Reprogramming.

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    Quan Wu

    2016-09-01

    Full Text Available The differential programming of sperm and eggs in gonads is a fundamental topic in reproductive biology. Although the sexual fate of germ cells is believed to be determined by signaling factors from sexually differentiated somatic cells in fetal gonads, the molecular mechanism that determines germ cell fate is poorly understood. Herein, we show that mothers against decapentaplegic homolog 4 (SMAD4 in germ cells is required for female-type differentiation. Germ cells in Smad4-deficient ovaries respond to retinoic acid signaling but fail to undergo meiotic prophase I, which coincides with the weaker expression of genes required for follicular formation, indicating that SMAD4 signaling is essential for oocyte differentiation and meiotic progression. Intriguingly, germline-specific deletion of Smad4 in Stra8-null female germ cells resulted in the up-regulation of genes required for male gonocyte differentiation, including Nanos2 and PLZF, suggesting the initiation of male-type differentiation in ovaries. Moreover, our transcriptome analyses of mutant ovaries revealed that the sex change phenotype is achieved without global gene expression changes in somatic cells. Our results demonstrate that SMAD4 and STRA8 are essential factors that regulate the female fate of germ cells.

  10. Bifunctional ectodermal stem cells around the nail display dual fate homeostasis and adaptive wounding response toward nail regeneration.

    Science.gov (United States)

    Leung, Yvonne; Kandyba, Eve; Chen, Yi-Bu; Ruffins, Seth; Chuong, Cheng-Ming; Kobielak, Krzysztof

    2014-10-21

    Regulation of adult stem cells (SCs) is fundamental for organ maintenance and tissue regeneration. On the body surface, different ectodermal organs exhibit distinctive modes of regeneration and the dynamics of their SC homeostasis remain to be unraveled. A slow cycling characteristic has been used to identify SCs in hair follicles and sweat glands; however, whether a quiescent population exists in continuously growing nails remains unknown. Using an in vivo label retaining cells (LRCs) system, we detected an unreported population of quiescent cells within the basal layer of the nail proximal fold, organized in a ring-like configuration around the nail root. These nail LRCs express the hair stem cell marker, keratin 15 (K15), and lineage tracing show that these K15-derived cells can contribute to both the nail structure and peri-nail epidermis, and more toward the latter. Thus, this stem cell population is bifunctional. Upon nail plucking injury, the homeostasis is tilted with these SCs dominantly delivering progeny to the nail matrix and differentiated nail plate, demonstrating their plasticity to adapt to wounding stimuli. Moreover, in vivo engraftment experiments established that transplanted nail LRCs can actively participate in functional nail regeneration. Transcriptional profiling of isolated nail LRCs revealed bone morphogenetic protein signaling favors nail differentiation over epidermal fate. Taken together, we have found a previously unidentified ring-configured population of bifunctional SCs, located at the interface between the nail appendage organ and adjacent epidermis, which physiologically display coordinated homeostatic dynamics but are capable of rediverting stem cell flow in response to injury.

  11. Properties and fate of oligodendrocyte progenitor cells in the corpus callosum, motor cortex, and piriform cortex of the mouse.

    Science.gov (United States)

    Clarke, Laura E; Young, Kaylene M; Hamilton, Nicola B; Li, Huiliang; Richardson, William D; Attwell, David

    2012-06-13

    Oligodendrocyte progenitor cells (OPCs) in the postnatal mouse corpus callosum (CC) and motor cortex (Ctx) reportedly generate only oligodendrocytes (OLs), whereas those in the piriform cortex may also generate neurons. OPCs have also been subdivided based on their expression of voltage-gated ion channels, ability to respond to neuronal activity, and proliferative state. To determine whether OPCs in the piriform cortex have inherently different physiological properties from those in the CC and Ctx, we studied acute brain slices from postnatal transgenic mice in which GFP expression identifies OL lineage cells. We whole-cell patch clamped GFP-expressing (GFP(+)) cells within the CC, Ctx, and anterior piriform cortex (aPC) and used prelabeling with 5-ethynyl-2'-deoxyuridine (EdU) to assess cell proliferation. After recording, slices were immunolabeled and OPCs were defined by strong expression of NG2. NG2(+) OPCs in the white and gray matter proliferated and coexpressed PDGFRα and voltage-gated Na(+) channels (I(Na)). Approximately 70% of OPCs were capable of generating regenerative depolarizations. In addition to OLIG2(+) NG2(+) I(Na)(+) OPCs and OLIG2(+) NG2(neg) I(Na)(neg) OLs, we identified cells with low levels of NG2 limited to the soma or the base of some processes. These cells had a significantly reduced I(Na) and a reduced ability to incorporate EdU when compared with OPCs and probably correspond to early differentiating OLs. By combining EdU labeling and lineage tracing using Pdgfrα-CreER(T2) : R26R-YFP transgenic mice, we double labeled OPCs and traced their fate in the postnatal brain. These OPCs generated OLs but did not generate neurons in the aPC or elsewhere at any time that we examined.

  12. Prolonged Ezh2 Depletion in Glioblastoma Causes a Robust Switch in Cell Fate Resulting in Tumor Progression

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    Nienke A. de Vries

    2015-01-01

    Full Text Available EZH2 is frequently overexpressed in glioblastoma (GBM, suggesting an oncogenic function that could be a target for therapeutic intervention. However, reduced EZH2 activity can also promote tumorigenesis, leading to concerns about the use of EZH2 inhibitors. Here, we provide further insight about the effects of prolonged Ezh2 inhibition in glioblastoma using preclinical mouse models and primary tumor-derived human GBM cell lines. Using doxycycline-inducible shRNAs that mimic the effects of a selective EZH2 inhibitor, we demonstrate that prolonged Ezh2 depletion causes a robust switch in cell fate, including significantly enhanced proliferation, DNA damage repair, and activation of part of the pluripotency network, resulting in altered tumor cell identity and tumor progression. Short-term Ezh2 depletion significantly improved survival without the tumor progression observed upon prolonged Ezh2 depletion, suggesting that precise dosing regiments are very important. These results could be of high clinical relevance with regard to how glioblastomas should be treated with epigenetic therapies.

  13. Modeling reveals bistability and low-pass filtering in the network module determining blood stem cell fate.

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    Jatin Narula

    2010-05-01

    Full Text Available Combinatorial regulation of gene expression is ubiquitous in eukaryotes with multiple inputs converging on regulatory control elements. The dynamic properties of these elements determine the functionality of genetic networks regulating differentiation and development. Here we propose a method to quantitatively characterize the regulatory output of distant enhancers with a biophysical approach that recursively determines free energies of protein-protein and protein-DNA interactions from experimental analysis of transcriptional reporter libraries. We apply this method to model the Scl-Gata2-Fli1 triad-a network module important for cell fate specification of hematopoietic stem cells. We show that this triad module is inherently bistable with irreversible transitions in response to physiologically relevant signals such as Notch, Bmp4 and Gata1 and we use the model to predict the sensitivity of the network to mutations. We also show that the triad acts as a low-pass filter by switching between steady states only in response to signals that persist for longer than a minimum duration threshold. We have found that the auto-regulation loops connecting the slow-degrading Scl to Gata2 and Fli1 are crucial for this low-pass filtering property. Taken together our analysis not only reveals new insights into hematopoietic stem cell regulatory network functionality but also provides a novel and widely applicable strategy to incorporate experimental measurements into dynamical network models.

  14. Cyclin D2 in the basal process of neural progenitors is linked to non-equivalent cell fates

    Science.gov (United States)

    Tsunekawa, Yuji; Britto, Joanne M; Takahashi, Masanori; Polleux, Franck; Tan, Seong-Seng; Osumi, Noriko

    2012-01-01

    Asymmetric cell division plays an indispensable role during corticogenesis for producing new neurons while maintaining a self-renewing pool of apical progenitors. The cellular and molecular determinants favouring asymmetric division are not completely understood. Here, we identify a novel mechanism for generating cellular asymmetry through the active transportation and local translation of Cyclin D2 mRNA in the basal process. This process is regulated by a unique cis-regulatory sequence found in the 3′ untranslated region (3′UTR) of the mRNA. Unequal inheritance of Cyclin D2 protein to the basally positioned daughter cell with the basal process confers renewal of the apical progenitor after asymmetric division. Conversely, depletion of Cyclin D2 in the apically positioned daughter cell results in terminal neuronal differentiation. We demonstrate that Cyclin D2 is also expressed in the developing human cortex within similar domains, thus indicating that its role as a fate determinant is ancient and conserved. PMID:22395070

  15. Simulation-based model checking approach to cell fate specification during Caenorhabditis elegans vulval development by hybrid functional Petri net with extension.

    Science.gov (United States)

    Li, Chen; Nagasaki, Masao; Ueno, Kazuko; Miyano, Satoru

    2009-04-27

    Model checking approaches were applied to biological pathway validations around 2003. Recently, Fisher et al. have proved the importance of model checking approach by inferring new regulation of signaling crosstalk in C. elegans and confirming the regulation with biological experiments. They took a discrete and state-based approach to explore all possible states of the system underlying vulval precursor cell (VPC) fate specification for desired properties. However, since both discrete and continuous features appear to be an indispensable part of biological processes, it is more appropriate to use quantitative models to capture the dynamics of biological systems. Our key motivation of this paper is to establish a quantitative methodology to model and analyze in silico models incorporating the use of model checking approach. A novel method of modeling and simulating biological systems with the use of model checking approach is proposed based on hybrid functional Petri net with extension (HFPNe) as the framework dealing with both discrete and continuous events. Firstly, we construct a quantitative VPC fate model with 1761 components by using HFPNe. Secondly, we employ two major biological fate determination rules - Rule I and Rule II - to VPC fate model. We then conduct 10,000 simulations for each of 48 sets of different genotypes, investigate variations of cell fate patterns under each genotype, and validate the two rules by comparing three simulation targets consisting of fate patterns obtained from in silico and in vivo experiments. In particular, an evaluation was successfully done by using our VPC fate model to investigate one target derived from biological experiments involving hybrid lineage observations. However, the understandings of hybrid lineages are hard to make on a discrete model because the hybrid lineage occurs when the system comes close to certain thresholds as discussed by Sternberg and Horvitz in 1986. Our simulation results suggest that: Rule I

  16. Intraclonal competition limits regulatory T cell fate determination in the thymus

    Science.gov (United States)

    Bautista, Jhoanne L.; Lio, Chan-Wang J.; Lathrop, Stephanie K.; Forbush, Katherine; Liang, Yuqiong; Luo, Jingqin; Rudensky, Alexander Y.; Hsieh, Chyi-Song

    2009-01-01

    Because the deletion of self-reactive T cells is incomplete, thymic development of natural Foxp3+CD4+ regulatory T (Treg) cells is required for preventing autoimmunity. However, the role of T cell receptor (TCR) specificity in thymic Treg cell development remains controversial. To address this issue, we generated a transgenic line expressing a naturally occurring Treg cell-derived TCR. Surprisingly, efficient thymic Treg cell development occurred only when the antigen-specific Treg cell precursors were present at low clonal frequency (<1%) within a normal thymus. Using retroviral vectors and bone marrow chimeras, we observed similar behavior with two other Treg cell-derived TCRs. These data demonstrate that thymic Treg cell development is a TCR-instructive process involving a niche which can be saturable at much lower clonal frequencies than the niche for positive selection. PMID:19430476

  17. Fate of transplanted bone marrow derived mesenchymal stem cells following spinal cord injury in rats by transplantation routes.

    Science.gov (United States)

    Kang, Eun-Sun; Ha, Kee-Yong; Kim, Young-Hoon

    2012-06-01

    This research was performed to investigate the differences of the transplanted cells' survival and differentiation, and its efficacy according to the delivery routes following spinal cord injury. Allogenic mesenchymal stem cells (MSCs) were transplanted intravenously (IV group) or intralesionally (IL group) at post-injury 1 day in rats. Behavioral improvement, engraftment and differentiation of the transplanted cells and the expression of neurotrophic factors of the transplanted groups were analyzed and compared with those of the control group. At 6 weeks post-injury, the mean BBB motor scales in the control, IV and IL groups were 6.5 ± 1.8, 11.1 ± 2.1, and 8.5 ± 2.8, respectively. Regardless of the delivery route, the MSCs transplantation following spinal cord injuries presented better behavioral improvement. The differentiations of the engrafted cells were different according to the delivery routes. The engrafted cells predominantly differentiated into astrocytes in the IV group and on the other hand, engrafted cells of the IL group demonstrated relatively even neural and glial differentiation. The expressions of neuronal growth factor were significantly higher in the IL group (mean relative optical density, 2.4 ± 0.15) than those in the control (2.16 ± 0.04) or IV group (1.7 ± 0.23). Transplantation of MSCs in the early stage of spinal cord injury gives a significant clinical improvement. However, the fate of the transplanted MSCs and expression of neuronal growth factors are different along the transplantation route.

  18. Long-term fate of the bile duct cells proliferated during chronic thioacetamide poisoning.

    Science.gov (United States)

    Malvaldi, G; Pollera, M

    1982-01-01

    The cell composition of the biliary proliferations induced by thioacetamide administration was investigated. At the end of the intoxication period the main cell types identified among the neoformed bile duct cells were as follows: i) poorly differentiated cells (oval cells) usually arranged in clusters or tiny cords, provided with a great amount of free ribosomes; ii) cells arranged in bile ducts of normal appearance; iii) cells arranged in bile ducts and showing intestinal metaplasia. After withdrawal of TAA most of the biliary proliferations disappeared; in the remaining ones, where the incorporation of 3H-thymidine was still appreciable, significant changes in the bile duct cell composition were evident; in fact whereas the oval cells were no longer identifiable, those suggesting an intestinal metaplasia underwent a relative increment as well as those displaying butyrocholinesterase activity; cells devoid of junctional apparatus and filled with free ribosomes were also seen. Some of the reported finding could support the hypothesis that the biological meaning of the different cell types arisen during intoxication is different; some of them could be due to a reactive hyperplasia, while other could be considered as representing a preneoplastic step.

  19. Distinct dendritic cell subsets dictate the fate decision between effector and memory CD8(+) T cell differentiation by a CD24-dependent mechanism.

    Science.gov (United States)

    Kim, Taeg S; Gorski, Stacey A; Hahn, Steven; Murphy, Kenneth M; Braciale, Thomas J

    2014-03-20

    The contribution of different DC subsets to effector and memory CD8(+) T cell generation during infection and the mechanism by which DCs controls these fate decisions is unclear. Here we demonstrated that the CD103(+) and CD11b(hi) migratory respiratory DC (RDC) subsets after influenza virus infection activated naive virus-specific CD8(+) T cells differentially. CD103(+) RDCs supported the generation of CD8(+) T effector (Teff) cells, which migrate from lymph nodes to the infected lungs. In contrast, migrant CD11b(hi) RDCs activated CD8(+) T cells characteristic of central memory CD8(+) T (CD8(+) Tcm) cells including retention within the draining lymph nodes. CD103(+) RDCs expressed CD24 at an elevated level, contributing to the propensity of this DC subpopulation to support CD8(+) Teff cell differentiation. Mechanistically, CD24 was shown to regulate CD8(+) T cell activation through HMGB1-mediated engagement of T cell RAGE. Thus, there is distribution of labor among DC subsets in regulating CD8(+) T cell differentiation. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. The Drosophila Transcription Factors Tinman and Pannier Activate and Collaborate with Myocyte Enhancer Factor-2 to Promote Heart Cell Fate.

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    TyAnna L Lovato

    Full Text Available Expression of the MADS domain transcription factor Myocyte Enhancer Factor 2 (MEF2 is regulated by numerous and overlapping enhancers which tightly control its transcription in the mesoderm. To understand how Mef2 expression is controlled in the heart, we identified a late stage Mef2 cardiac enhancer that is active in all heart cells beginning at stage 14 of embryonic development. This enhancer is regulated by the NK-homeodomain transcription factor Tinman, and the GATA transcription factor Pannier through both direct and indirect interactions with the enhancer. Since Tinman, Pannier and MEF2 are evolutionarily conserved from Drosophila to vertebrates, and since their vertebrate homologs can convert mouse fibroblast cells to cardiomyocytes in different activator cocktails, we tested whether over-expression of these three factors in vivo could ectopically activate known cardiac marker genes. We found that mesodermal over-expression of Tinman and Pannier resulted in approximately 20% of embryos with ectopic Hand and Sulphonylurea receptor (Sur expression. By adding MEF2 alongside Tinman and Pannier, a dramatic expansion in the expression of Hand and Sur was observed in almost all embryos analyzed. Two additional cardiac markers were also expanded in their expression. Our results demonstrate the ability to initiate ectopic cardiac fate in vivo by the combination of only three members of the conserved Drosophila cardiac transcription network, and provide an opportunity for this genetic model system to be used to dissect the mechanisms of cardiac specification.

  1. Fate and Effect of Intravenously Infused Mesenchymal Stem Cells in a Mouse Model of Hepatic Ischemia Reperfusion Injury and Resection

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    T. C. Saat

    2016-01-01

    Full Text Available Liver ischemia reperfusion injury (IRI is inevitable during transplantation and resection and is characterized by hepatocellular injury. Therapeutic strategies to reduce IRI and accelerate regeneration could offer major benefits. Mesenchymal stem cells (MSC are reported to have anti-inflammatory and regeneration promoting properties. We investigated the effect of MSC in a model of combined IRI and partial resection in the mouse. Hepatic IRI was induced by occlusion of 70% of the blood flow during 60 minutes, followed by 30% hepatectomy. 2 × 105 MSC or PBS were infused 2 hours before or 1 hour after IRI. Six, 48, and 120 hours postoperatively mice were sacrificed. Liver damage was evaluated by liver enzymes, histology, and inflammatory markers. Regeneration was determined by liver/body weight ratio, proliferating hepatocytes, and TGF-β levels. Fate of MSC was visualized with 3D cryoimaging. Infusion of 2 × 105 MSC 2 hours before or 1 hour after IRI and resection showed no beneficial effects. Tracking revealed that MSC were trapped in the lungs and did not migrate to the site of injury and many cells had already disappeared 2 hours after infusion. Based on these findings we conclude that intravenously infused MSC disappear rapidly and were unable to induce beneficial effects in a clinically relevant model of IRI and resection.

  2. Chromatin dynamics in Pollen Mother Cells underpin a common scenario at the somatic-to-reproductive fate transition of both the male and female lineages in Arabidopsis

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    Wenjing eShe

    2015-04-01

    Full Text Available Unlike animals, where the germline is established early during embryogenesis, plants set aside their reproductive lineage late in development in dedicated floral organs. The specification of pollen mother cells (PMCs committed to meiosis takes place in the sporogenous tissue in anther locules and marks the somatic-to-reproductive cell fate transition towards the male reproductive lineage. Here we show that Arabidopsis PMCs differentiation is accompanied by large-scale changes in chromatin organization. This is characterized by significant increase in nuclear volume, chromatin decondensation, reduction in heterochromatin, eviction of linker histones and the H2AZ histone variant. These structural alterations are accompanied by dramatic, quantitative changes in histone modifications levels compared to that of surrounding somatic cells that do not share a sporogenic fate. All these changes are highly reminiscent of those we have formerly described in female megaspore mother cells (MMCs. This indicates that chromatin reprogramming is a common underlying scenario in the somatic-to-reproductive cell fate transition in both male and female lineages.

  3. A germline-centric view of cell fate commitment, reprogramming and immortality.

    Science.gov (United States)

    Torres-Padilla, Maria-Elena; Ciosk, Rafal

    2013-02-01

    To ensure species continuity, the tantalising developmental plasticity of early embryonic cells, also called totipotency, must be transmitted to the offspring. This responsibility rests within the reproductive cell lineage: the germ line. At the recent EMBO/EMBL symposium 'Germline - Immortality through Totipotency', researchers discussed the mechanisms that establish and control totipotency, with an eye towards the mechanisms that may endow germ cells with the ability to propagate totipotency across generations.

  4. Legumain Regulates Differentiation Fate of Human Bone Marrow Stromal Cells and Is Altered in Postmenopausal Osteoporosis

    DEFF Research Database (Denmark)

    Jafari Kermani, Abbas; Qanie, Diyako; Andersen, Thomas L

    2017-01-01

    Secreted factors are a key component of stem cell niche and their dysregulation compromises stem cell function. Legumain is a secreted cysteine protease involved in diverse biological processes. Here, we demonstrate that legumain regulates lineage commitment of human bone marrow stromal cells...... and that its expression level and cellular localization are altered in postmenopausal osteoporotic patients. As shown by genetic and pharmacological manipulation, legumain inhibited osteoblast (OB) differentiation and in vivo bone formation through degradation of the bone matrix protein fibronectin...

  5. Hemocompatibility and selective cell fate of polydopamine-assisted heparinized PEO/PLLA composite coating on biodegradable AZ31 alloy.

    Science.gov (United States)

    Wei, Zhongling; Tian, Peng; Liu, Xuanyong; Zhou, Bangxin

    2014-09-01

    Biodegradable magnesium and its alloys have attracted much attention, as they have been used as cardiovascular stents recently because of their biodegradation after implantation. However, their corrosion resistance, hemocompatibility and surface biocompatibility are needed for practical applications. In this work, heparinization of the plasma electrolytic oxidation/poly(l-lactic acid) (PEO/PLLA) composite coating on biodegradable AZ31 alloy was achieved by the strong adhesion of mussel-inspired polydopamine (PDAM). The corrosion resistance of the coated substrates was evaluated in simulated body fluid. In particular, the hemolysis ratio and platelet adhesion tests were conducted to evaluate the hemocompatibility of the composite coatings. The in vitro cytotoxicity of the composite coatings was evaluated with human umbilical vein endothelial cells (HUVECs). The adhesion and proliferation of HUVECs and human umbilical artery smooth muscle cells (HUASMCs) directly incubated on the composite coatings were also investigated. The results showed that although PDAM modification and further heparinization reduced the corrosion resistance of the PEO/PLLA composite coating, the protection of the coating for the substrate was mainly maintained. Moreover, PDAM modification and further heparinization significantly suppressed the adhesion of platelets and had little influence on sustaining a low hemolysis ratio thus resulting in good surface hemocompatibility of the composite coating. The in vitro cell test demonstrated that none of the composite coatings presented obvious cytotoxicity. Significantly, after surface heparinization, the composite coating became more suitable for HUVEC growth and simultaneously inhibited HUASMC growth. The results show that further modification of the PEO/PLLA composite coating on biodegradable magnesium alloy is a promising method to obtain good surface hemocompatibility for anticoagulation and to regulate the cell fate for fast re

  6. The B-MYB Transcriptional Network Guides Cell Cycle Progression and Fate Decisions to Sustain Self-Renewal and the Identity of Pluripotent Stem Cells

    Science.gov (United States)

    Zhan, Ming; Riordon, Daniel R.; Yan, Bin; Tarasova, Yelena S.; Bruweleit, Sarah; Tarasov, Kirill V.; Li, Ronald A.; Wersto, Robert P.; Boheler, Kenneth R.

    2012-01-01

    Embryonic stem cells (ESCs) are pluripotent and have unlimited self-renewal capacity. Although pluripotency and differentiation have been examined extensively, the mechanisms responsible for self-renewal are poorly understood and are believed to involve an unusual cell cycle, epigenetic regulators and pluripotency-promoting transcription factors. Here we show that B-MYB, a cell cycle regulated phosphoprotein and transcription factor critical to the formation of inner cell mass, is central to the transcriptional and co-regulatory networks that sustain normal cell cycle progression and self-renewal properties of ESCs. Phenotypically, B-MYB is robustly expressed in ESCs and induced pluripotent stem cells (iPSCs), and it is present predominantly in a hypo-phosphorylated state. Knockdown of B-MYB results in functional cell cycle abnormalities that involve S, G2 and M phases, and reduced expression of critical cell cycle regulators like ccnb1 and plk1. By conducting gene expression profiling on control and B-MYB deficient cells, ChIP-chip experiments, and integrative computational analyses, we unraveled a highly complex B-MYB-mediated transcriptional network that guides ESC self-renewal. The network encompasses critical regulators of all cell cycle phases and epigenetic regulators, pluripotency transcription factors, and differentiation determinants. B-MYB along with E2F1 and c-MYC preferentially co-regulate cell cycle target genes. B-MYB also co-targets genes regulated by OCT4, SOX2 and NANOG that are significantly associated with stem cell differentiation, embryonic development, and epigenetic control. Moreover, loss of B-MYB leads to a breakdown of the transcriptional hierarchy present in ESCs. These results coupled with functional studies demonstrate that B-MYB not only controls and accelerates cell cycle progression in ESCs it contributes to fate decisions and maintenance of pluripotent stem cell identity. PMID:22936984

  7. The B-MYB transcriptional network guides cell cycle progression and fate decisions to sustain self-renewal and the identity of pluripotent stem cells.

    Directory of Open Access Journals (Sweden)

    Ming Zhan

    Full Text Available Embryonic stem cells (ESCs are pluripotent and have unlimited self-renewal capacity. Although pluripotency and differentiation have been examined extensively, the mechanisms responsible for self-renewal are poorly understood and are believed to involve an unusual cell cycle, epigenetic regulators and pluripotency-promoting transcription factors. Here we show that B-MYB, a cell cycle regulated phosphoprotein and transcription factor critical to the formation of inner cell mass, is central to the transcriptional and co-regulatory networks that sustain normal cell cycle progression and self-renewal properties of ESCs. Phenotypically, B-MYB is robustly expressed in ESCs and induced pluripotent stem cells (iPSCs, and it is present predominantly in a hypo-phosphorylated state. Knockdown of B-MYB results in functional cell cycle abnormalities that involve S, G2 and M phases, and reduced expression of critical cell cycle regulators like ccnb1 and plk1. By conducting gene expression profiling on control and B-MYB deficient cells, ChIP-chip experiments, and integrative computational analyses, we unraveled a highly complex B-MYB-mediated transcriptional network that guides ESC self-renewal. The network encompasses critical regulators of all cell cycle phases and epigenetic regulators, pluripotency transcription factors, and differentiation determinants. B-MYB along with E2F1 and c-MYC preferentially co-regulate cell cycle target genes. B-MYB also co-targets genes regulated by OCT4, SOX2 and NANOG that are significantly associated with stem cell differentiation, embryonic development, and epigenetic control. Moreover, loss of B-MYB leads to a breakdown of the transcriptional hierarchy present in ESCs. These results coupled with functional studies demonstrate that B-MYB not only controls and accelerates cell cycle progression in ESCs it contributes to fate decisions and maintenance of pluripotent stem cell identity.

  8. The Bile Acid Nuclear Receptor FXRα Is a Critical Regulator of Mouse Germ Cell Fate

    Directory of Open Access Journals (Sweden)

    Emmanuelle Martinot

    2017-07-01

    Full Text Available Spermatogenesis is the process by which spermatozoa are generated from spermatogonia. This cell population is heterogeneous, with self-renewing spermatogonial stem cells (SSCs and progenitor spermatogonia that will continue on a path of differentiation. Only SSCs have the ability to regenerate and sustain spermatogenesis. This makes the testis a good model to investigate stem cell biology. The Farnesoid X Receptor alpha (FXRα was recently shown to be expressed in the testis. However, its global impact on germ cell homeostasis has not yet been studied. Here, using a phenotyping approach in Fxrα−/− mice, we describe unexpected roles of FXRα on germ cell physiology independent of its effects on somatic cells. FXRα helps establish and maintain an undifferentiated germ cell pool and in turn influences male fertility. FXRα regulates the expression of several pluripotency factors. Among these, in vitro approaches show that FXRα controls the expression of the pluripotency marker Lin28 in the germ cells.

  9. ZFPIP/Zfp462 is involved in P19 cell pluripotency and in their neuronal fate

    Energy Technology Data Exchange (ETDEWEB)

    Masse, Julie [CNRS UMR 6061, Institut de Genetique et Developpement de Rennes (IGDR), Rennes (France); Universite de Rennes 1, 35043 Rennes cedex (France); Piquet-Pellorce, Claire [Universite de Rennes 1, 35043 Rennes cedex, EA 4427 SeRAIC (France); Viet, Justine; Guerrier, Daniel; Pellerin, Isabelle [CNRS UMR 6061, Institut de Genetique et Developpement de Rennes (IGDR), Rennes (France); Universite de Rennes 1, 35043 Rennes cedex (France); Deschamps, Stephane, E-mail: stephane.deschamps@univ-rennes1.fr [CNRS UMR 6061, Institut de Genetique et Developpement de Rennes (IGDR), Rennes (France); Universite de Rennes 1, 35043 Rennes cedex (France)

    2011-08-01

    The nuclear zinc finger protein ZFPIP/Zfp462 is an important factor involved in cell division during the early embryonic development of vertebrates. In pluripotent P19 cells, ZFPIP/Zfp462 takes part in cell proliferation, likely via its role in maintaining chromatin structure. To further define the function of ZFPIP/Zfp462 in the mechanisms of pluripotency and cell differentiation, we constructed a stable P19 cell line in which ZFPIP/Zfp462 knockdown is inducible. We report that ZFPIP/Zfp462 was vital for mitosis and self-renewal in pluripotent P19 cells. Its depletion induced substantial decreases in the expression of the pluripotency genes Nanog, Oct4 and Sox2 and was associated with the transient expression of specific neuronal differentiation markers. We also demonstrated that ZFPIP/Zfp462 expression appears to be unnecessary after neuronal differentiation is induced in P19 cells. Taken together, our results strongly suggest that ZFPIP/Zfp462 is a key chromatin factor involved in maintaining P19 pluripotency and in the early mechanisms of neural differentiation but that it is dispensable in differentiated P19 cells.

  10. Uptake and fate of ouabain bound to HeLa cells. [/sup 3/H tracer study

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J. S.; Brake, E. T.

    1977-01-01

    The first step in the pharmacologic interaction of a cardiac glycoside with cells is the binding of the drug to its specific surface receptor, an exteriorly oriented site of the Na/sup +/--K/sup +/ ATPase. The purpose of the study outlined was to follow a glycoside from its initial binding to its ultimate release from a sensitive cell, and in parallel studies to observe the recovery of the cells from glycoside intoxication. The glycoside used is /sup 3/H-ouabain, and the cells are from the S3 clone of HeLa. HeLa cells are used principally because of their intrinsic interest as a human cell type. In addition, having been cloned, they can be grown as a homogeneous population, which greatly simplifies the interpretation of the results. Finally, after pulse treatment with the drug, the cells can be returned to a complete medium with adequate supplies of serum, amino acids, vitamins, and energy sources. In this normal environment, not only can the short term physiologic responses be assessed but, with the growth requirements of the cells fulfilled, any recovery processes dependent on macromolecular-synthesis can also be observed.

  11. Mitochondria-Associated Membranes As Networking Platforms and Regulators of Cancer Cell Fate

    Directory of Open Access Journals (Sweden)

    Maria Livia Sassano

    2017-08-01

    Full Text Available The tight cross talk between two essential organelles of the cell, the endoplasmic reticulum (ER and mitochondria, is spatially and functionally regulated by specific microdomains known as the mitochondria-associated membranes (MAMs. MAMs are hot spots of Ca2+ transfer between the ER and mitochondria, and emerging data indicate their vital role in the regulation of fundamental physiological processes, chief among them mitochondria bioenergetics, proteostasis, cell death, and autophagy. Moreover, and perhaps not surprisingly, it has become clear that signaling events regulated at the ER–mitochondria intersection regulate key processes in oncogenesis and in the response of cancer cells to therapeutics. ER–mitochondria appositions have been shown to dynamically recruit oncogenes and tumor suppressors, modulating their activity and protein complex formation, adapt the bioenergetic demand of cancer cells and to regulate cell death pathways and redox signaling in cancer cells. In this review, we discuss some emerging players of the ER–mitochondria contact sites in mammalian cells, the key processes they regulate and recent evidence highlighting the role of MAMs in shaping cell-autonomous and non-autonomous signals that regulate cancer growth.

  12. Role of substrate biomechanics in controlling (stem) cell fate: Implications in regenerative medicine.

    Science.gov (United States)

    Macri-Pellizzeri, Laura; De-Juan-Pardo, Elena M; Prosper, Felipe; Pelacho, Beatriz

    2017-10-11

    Tissue-specific stem cells reside in a specialized environment known as niche. The niche plays a central role in the regulation of cell behaviour and, through the concerted action of soluble molecules, supportive somatic cells, and extracellular matrix components, directs stem cells to proliferate, differentiate, or remain quiescent. Great efforts have been done to decompose and separately analyse the contribution of these cues in the in vivo environment. Specifically, the mechanical properties of the extracellular matrix influence many aspects of cell behaviour, including self-renewal and differentiation. Deciphering the role of biomechanics could thereby provide important insights to control the stem cells responses in a more effective way with the aim to promote their therapeutic potential. In this review, we provide a wide overview of the effect that the microenvironment stiffness exerts on the control of cell behaviour with a particular focus on the induction of stem cells differentiation. We also describe the process of mechanotransduction and the molecular effectors involved. Finally, we critically discuss the potential involvement of tissue biomechanics in the design of novel tissue engineering strategies. Copyright © 2017 John Wiley & Sons, Ltd.

  13. Control of Paneth Cell Fate, Intestinal Inflammation, and Tumorigenesis by PKCλ/ι

    Directory of Open Access Journals (Sweden)

    Yuki Nakanishi

    2016-09-01

    Full Text Available Paneth cells are a highly specialized population of intestinal epithelial cells located in the crypt adjacent to Lgr5+ stem cells, from which they differentiate through a process that requires downregulation of the Notch pathway. Their ability to store and release antimicrobial peptides protects the host from intestinal pathogens and controls intestinal inflammation. Here, we show that PKCλ/ι is required for Paneth cell differentiation at the level of Atoh1 and Gfi1, through the control of EZH2 stability by direct phosphorylation. The selective inactivation of PKCλ/ι in epithelial cells results in the loss of mature Paneth cells, increased apoptosis and inflammation, and enhanced tumorigenesis. Importantly, PKCλ/ι expression in human Paneth cells decreases with progression of Crohn’s disease. Kaplan-Meier survival analysis of colorectal cancer (CRC patients revealed that low PRKCI levels correlated with significantly worse patient survival rates. Therefore, PKCλ/ι is a negative regulator of intestinal inflammation and cancer through its role in Paneth cell homeostasis.

  14. Bone Marrow Cells in Acute Lymphoblastic Leukemia Create a Proinflammatory Microenvironment Influencing Normal Hematopoietic Differentiation Fates

    Science.gov (United States)

    Vilchis-Ordoñez, Armando; Contreras-Quiroz, Adriana; Dorantes-Acosta, Elisa; Reyes-López, Alfonso; Quintela-Nuñez del Prado, Henry Martin; Venegas-Vázquez, Jorge; Mayani, Hector; Ortiz-Navarrete, Vianney; López-Martínez, Briceida; Pelayo, Rosana

    2015-01-01

    B-cell acute lymphoblastic leukemia (B-ALL) is a serious public health problem in the pediatric population worldwide, contributing to 85% of deaths from childhood cancers. Understanding the biology of the disease is crucial for its clinical management and the development of therapeutic strategies. In line with that observed in other malignancies, chronic inflammation may contribute to a tumor microenvironment resulting in the damage of normal processes, concomitant to development and maintenance of neoplastic cells. We report here that hematopoietic cells from bone marrow B-ALL have the ability to produce proinflammatory and growth factors, including TNFα, IL-1β, IL-12, and GM-CSF that stimulate proliferation and differentiation of normal stem and progenitor cells. Our findings suggest an apparently distinct CD13+CD33+ population of leukemic cells contributing to a proinflammatory microenvironment that may be detrimental to long-term normal hematopoiesis within B-ALL bone marrow. PMID:26090405

  15. Bone Marrow Cells in Acute Lymphoblastic Leukemia Create a Proinflammatory Microenvironment Influencing Normal Hematopoietic Differentiation Fates

    Directory of Open Access Journals (Sweden)

    Armando Vilchis-Ordoñez

    2015-01-01

    Full Text Available B-cell acute lymphoblastic leukemia (B-ALL is a serious public health problem in the pediatric population worldwide, contributing to 85% of deaths from childhood cancers. Understanding the biology of the disease is crucial for its clinical management and the development of therapeutic strategies. In line with that observed in other malignancies, chronic inflammation may contribute to a tumor microenvironment resulting in the damage of normal processes, concomitant to development and maintenance of neoplastic cells. We report here that hematopoietic cells from bone marrow B-ALL have the ability to produce proinflammatory and growth factors, including TNFα, IL-1β, IL-12, and GM-CSF that stimulate proliferation and differentiation of normal stem and progenitor cells. Our findings suggest an apparently distinct CD13+CD33+ population of leukemic cells contributing to a proinflammatory microenvironment that may be detrimental to long-term normal hematopoiesis within B-ALL bone marrow.

  16. Methamphetamine decreases dentate gyrus stem cell self-renewal and shifts the differentiation towards neuronal fate

    Directory of Open Access Journals (Sweden)

    Sofia Baptista

    2014-09-01

    Full Text Available Methamphetamine (METH is a highly addictive psychostimulant drug of abuse that negatively interferes with neurogenesis. In fact, we have previously shown that METH triggers stem/progenitor cell death and decreases neuronal differentiation in the dentate gyrus (DG. Still, little is known regarding its effect on DG stem cell properties. Herein, we investigate the impact of METH on mice DG stem/progenitor cell self-renewal functions. METH (10 nM decreased DG stem cell self-renewal, while 1 nM delayed cell cycle in the G0/G1-to-S phase transition and increased the number of quiescent cells (G0 phase, which correlated with a decrease in cyclin E, pEGFR and pERK1/2 protein levels. Importantly, both drug concentrations (1 or 10 nM did not induce cell death. In accordance with the impairment of self-renewal capacity, METH (10 nM decreased Sox2+/Sox2+ while increased Sox2−/Sox2− pairs of daughter cells. This effect relied on N-methyl-d-aspartate (NMDA signaling, which was prevented by the NMDA receptor antagonist, MK-801 (10 μM. Moreover, METH (10 nM increased doublecortin (DCX protein levels consistent with neuronal differentiation. In conclusion, METH alters DG stem cell properties by delaying cell cycle and decreasing self-renewal capacities, mechanisms that may contribute to DG neurogenesis impairment followed by cognitive deficits verified in METH consumers.

  17. On the fate of primordial germ cells injected into early mouse embryos.

    Science.gov (United States)

    Leitch, Harry G; Okamura, Daiji; Durcova-Hills, Gabriela; Stewart, Colin L; Gardner, Richard L; Matsui, Yasuhisa; Papaioannou, Virginia E

    2014-01-15

    Primordial germ cells (PGCs) are the founder cells of the germline. Via gametogenesis and fertilisation this lineage generates a new embryo in the next generation. PGCs are also the cell of origin of multilineage teratocarcinomas. In vitro, mouse PGCs can give rise to embryonic germ (EG) cells - pluripotent stem cells that can contribute to primary chimaeras when introduced into pre-implantation embryos. Thus, PGCs can give rise to pluripotent cells in the course of the developmental cycle, during teratocarcinogenesis and by in vitro culture. However, there is no evidence that PGCs can differentiate directly into somatic cell types. Furthermore, it is generally assumed that PGCs do not contribute to chimaeras following injection into the early mouse embryo. However, these data have never been formally published. Here, we present the primary data from the original PGC-injection experiments performed 40 years ago, alongside results from more recent studies in three separate laboratories. These results have informed and influenced current models of the relationship between pluripotency and the germline cycle. Current technologies allow further experiments to confirm and expand upon these findings and allow definitive conclusions as to the developmental potency of PGCs. © 2013 The Authors. Published by Elsevier Inc. All rights reserved.

  18. Nontelomeric TRF2-REST Interaction Modulates Neuronal Gene Silencing and Fate of Tumor and Stem Cells

    OpenAIRE

    Zhang, Peisu; Pazin, Michael J.; Schwartz, Catherine M.; Kevin G Becker; Robert P Wersto; Dilley, Caroline M.; Mark P Mattson

    2008-01-01

    Removal of TRF2, a telomere shelterin protein, recapitulates key aspects of telomere attrition including the DNA-damage response and cell-cycle arrest [1]. Distinct from the response of proliferating cells to loss of TRF2 [2, 3], in rodent non-cycling cells, TRF2 inhibition promotes differentiation and growth [4, 5]. However, the mechanism that couples telomere gene-silencing features [6-8] to differentiation programs has yet to be elucidated. Here we describe an extra-telomeric function of T...

  19. What's Luck Got to Do with It: Single Cells, Multiple Fates, and Biological Nondeterminism

    National Research Council Canada - National Science Library

    Symmons, Orsolya; Raj, Arjun

    2016-01-01

    .... Conceptual progress, however, has been comparatively slow. Here, we provide a framework for classifying both the origins of the differences between individual cells and the consequences of those differences...

  20. N-cadherin adhesive interactions modulate matrix mechanosensing and fate commitment of mesenchymal stem cells

    Science.gov (United States)

    Cosgrove, Brian D.; Mui, Keeley L.; Driscoll, Tristan P.; Caliari, Steven R.; Mehta, Kush D.; Assoian, Richard K.; Burdick, Jason A.; Mauck, Robert L.

    2016-12-01

    During mesenchymal development, the microenvironment gradually transitions from one that is rich in cell-cell interactions to one that is dominated by cell-ECM (extracellular matrix) interactions. Because these cues cannot readily be decoupled in vitro or in vivo, how they converge to regulate mesenchymal stem cell (MSC) mechanosensing is not fully understood. Here, we show that a hyaluronic acid hydrogel system enables, across a physiological range of ECM stiffness, the independent co-presentation of the HAVDI adhesive motif from the EC1 domain of N-cadherin and the RGD adhesive motif from fibronectin. Decoupled presentation of these cues revealed that HAVDI ligation (at constant RGD ligation) reduced the contractile state and thereby nuclear YAP/TAZ localization in MSCs, resulting in altered interpretation of ECM stiffness and subsequent changes in downstream cell proliferation and differentiation. Our findings reveal that, in an evolving developmental context, HAVDI/N-cadherin interactions can alter stem cell perception of the stiffening extracellular microenvironment.

  1. The Fate of a Normal Human Cell Traversed by a Single Charged Particle

    Science.gov (United States)

    Fournier, C.; Zahnreich, S.; Kraft, D.; Friedrich, T.; Voss, K.-O.; Durante, M.; Ritter, S.

    2012-01-01

    The long-term “fate” of normal human cells after single hits of charged particles is one of the oldest unsolved issues in radiation protection and cellular radiobiology. Using a high-precision heavy-ion microbeam we could target normal human fibroblasts with exactly one or five carbon ions and measured the early cytogenetic damage and the late behaviour using single-cell cloning. Around 70% of the first cycle cells presented visible aberrations in mFISH after a single ion traversal, and about 5% of the cells were still able to form colonies. In one third of selected high-proliferative colonies we observed clonal (radiation-induced) aberrations. Terminal differentiation and markers of senescence (PCNA, p16) in the descendants of cells traversed by one carbon ion occurred earlier than in controls, but no evidence of radiation-induced chromosomal instability was found. We conclude that cells surviving single-ion traversal, often carrying clonal chromosome aberrations, undergo accelerated senescence but maintain chromosomal stability. PMID:22966418

  2. Regulatory Role of Redox Balance in Determination of Neural Precursor Cell Fate

    Directory of Open Access Journals (Sweden)

    Mohamed Ariff Iqbal

    2017-01-01

    Full Text Available In 1990s, reports of discovery of a small group of cells capable of proliferation and contribution to formation of new neurons in the central nervous system (CNS reversed a century-old concept on lack of neurogenesis in the adult mammalian brain. These cells are found in all stages of human life and contribute to normal cellular turnover of the CNS. Therefore, the identity of regulating factors that affect their proliferation and differentiation is a highly noteworthy issue for basic scientists and their clinician counterparts for therapeutic purposes. The cues for such control are embedded in developmental and environmental signaling through a highly regulated tempo-spatial expression of specific transcription factors. Novel findings indicate the importance of reactive oxygen species (ROS in the regulation of this signaling system. The elusive nature of ROS signaling in many vital processes from cell proliferation to cell death creates a complex literature in this field. Here, we discuss the emerging thoughts on the importance of redox regulation of proliferation and maintenance in mammalian neural stem and progenitor cells under physiological and pathological conditions. The current knowledge on ROS-mediated changes in redox-sensitive proteins that govern the molecular mechanisms in proliferation and differentiation of these cells is reviewed.

  3. Cell fate specification in the Drosophila salivary gland: the integration of homeotic gene function with the DPP signaling cascade.

    Science.gov (United States)

    Henderson, K D; Isaac, D D; Andrew, D J

    1999-01-01

    Salivary gland formation in the Drosophila embryo is linked to the expression of the homeotic gene Sex combs reduced (Scr). When Scr function is missing, salivary glands do not form, and when SCR is expressed everywhere, salivary glands form in new places. However, not every cell that expresses Scr is recruited to a salivary gland fate. Along the anterior-posterior axis, the posteriorly expressed proteins encoded by the teashirt (tsh) and Abdominal-B (Abd-B) genes block SCR activation of salivary gland genes, and along the dorsal-ventral axis, the secreted signaling molecule encoded by decapentaplegic (dpp) prevents activation of salivary gland genes by SCR in dorsal regions of parasegment 2. We have identified five downstream components in the DPP signaling cascade required to block salivary gland gene activation. These components include two known receptors, the type I receptor encoded by the thick veins (tkv) gene and the type II receptor encoded by the punt (put) gene; two of the four known Drosophila members of the Smad family of proteins which transduce signals from the receptors to the nucleus, Mothers against dpp (Mad) and Medea (Med); and, finally, a large zinc-finger transcription factor encoded by the schnurri (shn) gene. These results reveal how anterior-posterior and dorsal-ventral patterning information is integrated at the level of organ-specific gene expression. Copyright 1999 Academic Press.

  4. Microcephaly Proteins Wdr62 and Aspm Define a Mother Centriole Complex Regulating Centriole Biogenesis, Apical Complex, and Cell Fate.

    Science.gov (United States)

    Jayaraman, Divya; Kodani, Andrew; Gonzalez, Dilenny M; Mancias, Joseph D; Mochida, Ganeshwaran H; Vagnoni, Cristiana; Johnson, Jeffrey; Krogan, Nevan; Harper, J Wade; Reiter, Jeremy F; Yu, Timothy W; Bae, Byoung-Il; Walsh, Christopher A

    2016-11-23

    Mutations in several genes encoding centrosomal proteins dramatically decrease the size of the human brain. We show that Aspm (abnormal spindle-like, microcephaly-associated) and Wdr62 (WD repeat-containing protein 62) interact genetically to control brain size, with mice lacking Wdr62, Aspm, or both showing gene dose-related centriole duplication defects that parallel the severity of the microcephaly and increased ectopic basal progenitors, suggesting premature delamination from the ventricular zone. Wdr62 and Aspm localize to the proximal end of the mother centriole and interact physically, with Wdr62 required for Aspm localization, and both proteins, as well as microcephaly protein Cep63, required to localize CENPJ/CPAP/Sas-4, a final common target. Unexpectedly, Aspm and Wdr62 are required for normal apical complex localization and apical epithelial structure, providing a plausible unifying mechanism for the premature delamination and precocious differentiation of progenitors. Together, our results reveal links among centrioles, apical proteins, and cell fate, and illuminate how alterations in these interactions can dynamically regulate brain size. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Effects of Recording Food Intake Using Cell Phone Camera Pictures on Energy Intake and Food Choice.

    Science.gov (United States)

    Doumit, Rita; Long, JoAnn; Kazandjian, Chant; Gharibeh, Nathalie; Karam, Lina; Song, Huaxin; Boswell, Carol; Zeeni, Nadine

    2016-06-01

    The well-documented increases in obesity and unhealthy dietary practices substantiate the need for evidence-based tools that can help people improve their dietary habits. The current spread of mobile phone-embedded cameras offers new opportunities for recording food intake. Moreover, the act of taking pictures of food consumed may enhance visual consciousness of food choice and quantity. The present study aimed to assess the effect of using cell phone pictures to record food intake on energy intake and food choice in college students. The effectiveness and acceptability of cell phone picture-based diet recording also was assessed. A repeated measures crossover design was used. One group of participants entered their food intake online during 3 days based on their memory, although a second group recorded their food intake using cell phone pictures as their reference. Participants then crossed over to complete 3 more days of diet recording using the alternate method. Focus groups were conducted to obtain feedback on the effectiveness and acceptability of cell phone picture-based diet recording. Intake of meat and vegetable servings were significantly higher in the memory period compared with the cell phone period, regardless of the order. Results from the focus group indicated a positive attitude toward the use of cell phone pictures in recording food intake and an increased awareness of food choice and portion size. Cell phone pictures may be an easy, relevant, and accessible method of diet self-monitoring when aiming at dietary changes. Future trials should combine this technique with healthy eating education. © 2015 Sigma Theta Tau International.

  6. Cell milieu significantly affects the fate of AApoAI amyloidogenic variants: predestination or serendipity?

    Science.gov (United States)

    Gaglione, Rosa; Smaldone, Giovanni; Di Girolamo, Rocco; Piccoli, Renata; Pedone, Emilia; Arciello, Angela

    2018-03-01

    Specific apolipoprotein A-I variants are associated to severe hereditary amyloidoses. The organ distribution of AApoAI amyloidosis seems to depend on the position of the mutation, since mutations in residues from 1 to 75 are mainly associated to hepatic and renal amyloidosis, while mutations in residues from 173 to 178 are mostly responsible for cardiac, laryngeal, and cutaneous amyloidosis. Molecular bases of this tissue specificity are still poorly understood, but it is increasingly emerging that protein destabilization induced by amyloidogenic mutations is neither necessary nor sufficient for amyloidosis development. By using a multidisciplinary approach, including circular dichroism, dynamic light scattering, spectrofluorometric and atomic force microscopy analyses, the effect of target cells on the conformation and fibrillogenic pathway of the two AApoAI amyloidogenic variants AApoAI L75P and AApoAI L174S has been monitored. Our data show that specific cell milieus selectively affect conformation, aggregation propensity and fibrillogenesis of the two AApoAI amyloidogenic variants. An intriguing picture emerged indicating that defined cell contexts selectively induce fibrillogenesis of specific AApoAI variants. An innovative methodological approach, based on the use of whole intact cells to monitor the effects of cell context on AApoAI variants fibrillogenic pathway, has been set up. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Gene dosage imbalance during DNA replication controls bacterial cell-fate decision

    Science.gov (United States)

    Igoshin, Oleg

    Genes encoding proteins in a common regulatory network are frequently located close to one another on the chromosome to facilitate co-regulation or couple gene expression to growth rate. Contrasting with these observations, here we demonstrate a functional role for the arrangement of Bacillus subtilis sporulation network genes on opposite sides of the chromosome. We show that the arrangement of two sporulation network genes, one located close to the origin, the other close to the terminus leads to a transient gene dosage imbalance during chromosome replication. This imbalance is detected by the sporulation network to produce cell-cycle coordinated pulses of the sporulation master regulator Spo0A~P. This pulsed response allows cells to decide between sporulation and continued vegetative growth during each cell-cycle spent in starvation. Furthermore, changes in DNA replication and cell-cycle parameters with decreased growth rate in starvation conditions enable cells to indirectly detect starvation without the need for evaluating specific metabolites. The simplicity of the uncovered coordination mechanism and starvation sensing suggests that it may be widely applicable in a variety of gene regulatory and stress-response settings. This work is supported by National Science Foundation Grants MCB-1244135, EAGER-1450867, MCB-1244423, NIH NIGMS Grant R01 GM088428 and HHMI International Student Fellowship.

  8. Optimization of Femtosecond Laser Polymerized Structural Niches to Control Mesenchymal Stromal Cell Fate in Culture

    Directory of Open Access Journals (Sweden)

    Manuela T. Raimondi

    2014-06-01

    Full Text Available We applied two-photon polymerization to fabricate 3D synthetic niches arranged in complex patterns to study the effect of mechano-topological parameters on morphology, renewal and differentiation of rat mesenchymal stromal cells. Niches were formed in a photoresist with low auto-fluorescence, which enabled the clear visualization of the fluorescence emission of the markers used for biological diagnostics within the internal niche structure. The niches were structurally stable in culture up to three weeks. At three weeks of expansion in the niches, cell density increased by almost 10-fold and was 67% greater than in monolayer culture. Evidence of lineage commitment was observed in monolayer culture surrounding the structural niches, and within cell aggregates, but not inside the niches. Thus, structural niches were able not only to direct stem cell homing and colony formation, but also to guide aggregate formation, providing increased surface-to-volume ratios and space for stem cells to adhere and renew, respectively.

  9. Lentiviral Fluorescent Genetic Barcoding for Multiplex Fate Tracking of Leukemic Cells

    Directory of Open Access Journals (Sweden)

    Tobias Maetzig

    2017-09-01

    Full Text Available Tracking the behavior of leukemic samples both in vitro and in vivo plays an increasingly large role in efforts to better understand the leukemogenic processes and the effects of potential new therapies. Such work can be accelerated and made more efficient by methodologies enabling the characterization of leukemia samples in multiplex assays. We recently developed three sets of lentiviral fluorescent genetic barcoding (FGB vectors that create 26, 14, and 6 unique immunophenotyping-compatible color codes from GFP-, yellow fluorescent protein (YFP-, and monomeric kusabira orange 2 (mKO2-derived fluorescent proteins. These vectors allow for labeling and tracking of individual color-coded cell populations in mixed samples by real-time flow cytometry. Using the prototypical Hoxa9/Meis1 murine model of acute myeloid leukemia, we describe the application of the 6xFGB vector system for assessing leukemic cell characteristics in multiplex assays. By transplanting color-coded cell mixes, we investigated the competitive growth behavior of individual color-coded populations, determined leukemia-initiating cell frequencies, and assessed the dose-dependent potential of cells exposed to the histone deacetylase inhibitor Entinostat for bone marrow homing. Thus, FGB provides a useful tool for the multiplex characterization of leukemia samples in a wide variety of applications with a concomitant reduction in workload, processing times, and mouse utilization.

  10. Ectopic expression of the immune adaptor protein CD3zeta in neural stem/progenitor cells disrupts cell-fate specification.

    Science.gov (United States)

    Angibaud, Julie; Baudouin, Stéphane J; Louveau, Antoine; Nerrière-Daguin, Véronique; Bonnamain, Virginie; Csaba, Zsolt; Dournaud, Pascal; Naveilhan, Philippe; Noraz, Nelly; Pellier-Monnin, Véronique; Boudin, Hélène

    2012-02-01

    Immune signaling and neuroinflammatory mediators have recently emerged as influential variables that regulate neural precursor/stem cell (NPC) behavior and function. In this study, we investigated whether the signaling adaptor protein CD3ζ, a transmembrane protein involved in T cell differentiation and function and recently shown to regulate neuronal development in the central nervous system (CNS), may have a role in NPC differentiation. We analyzed the expression profile of CD3ζ in embryonic rat brain during neurogenic periods and in neurosphere-derived neural cells, and we investigated the action of CD3ζ on cell differentiation. We found that CD3ζ expression coincided with neuronal commitment, but its forced expression in NPCs prevented the production of neurons and oligodendrocytes, but not astroglial cells. This blockade of neuronal differentiation was operated through an ITAM-independent mechanism, but required the Asp36 of the CD3ζ transmembrane domain involved in membrane receptor interaction. Together, our findings show that ectopic CD3ζ expression in NPCs impaired their normal cell-fate specification and suggest that variations of CD3ζ expression in the developing CNS might result in neurodevelopmental anomalies.

  11. An oncogenic MYB feedback loop drives alternate cell fates in adenoid cystic carcinoma.

    Science.gov (United States)

    Drier, Yotam; Cotton, Matthew J; Williamson, Kaylyn E; Gillespie, Shawn M; Ryan, Russell J H; Kluk, Michael J; Carey, Christopher D; Rodig, Scott J; Sholl, Lynette M; Afrogheh, Amir H; Faquin, William C; Queimado, Lurdes; Qi, Jun; Wick, Michael J; El-Naggar, Adel K; Bradner, James E; Moskaluk, Christopher A; Aster, Jon C; Knoechel, Birgit; Bernstein, Bradley E

    2016-03-01

    Translocation events are frequent in cancer and may create chimeric fusions or 'regulatory rearrangements' that drive oncogene overexpression. Here we identify super-enhancer translocations that drive overexpression of the oncogenic transcription factor MYB as a recurrent theme in adenoid cystic carcinoma (ACC). Whole-genome sequencing data and chromatin maps highlight distinct chromosomal rearrangements that juxtapose super-enhancers to the MYB locus. Chromosome conformation capture confirms that the translocated enhancers interact with the MYB promoter. Remarkably, MYB protein binds to the translocated enhancers, creating a positive feedback loop that sustains its expression. MYB also binds enhancers that drive different regulatory programs in alternate cell lineages in ACC, cooperating with TP63 in myoepithelial cells and a Notch program in luminal epithelial cells. Bromodomain inhibitors slow tumor growth in ACC primagraft models in vivo. Thus, our study identifies super-enhancer translocations that drive MYB expression and provides insight into downstream MYB functions in alternate ACC lineages.

  12. What's Luck Got to Do with It: Single Cells, Multiple Fates, and Biological Nondeterminism.

    Science.gov (United States)

    Symmons, Orsolya; Raj, Arjun

    2016-06-02

    The field of single-cell biology has morphed from a philosophical digression at its inception, to a playground for quantitative biologists, to a major area of biomedical research. The last several years have witnessed an explosion of new technologies, allowing us to apply even more of the modern molecular biology toolkit to single cells. Conceptual progress, however, has been comparatively slow. Here, we provide a framework for classifying both the origins of the differences between individual cells and the consequences of those differences. We discuss how the concept of "random" differences is context dependent, and propose that rigorous definitions of inputs and outputs may bring clarity to the discussion. We also categorize ways in which probabilistic behavior may influence cellular function, highlighting studies that point to exciting future directions in the field. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. Sin3a regulates epithelial progenitor cell fate during lung development.

    Science.gov (United States)

    Yao, Changfu; Carraro, Gianni; Konda, Bindu; Guan, Xiangrong; Mizuno, Takako; Chiba, Norika; Kostelny, Matthew; Kurkciyan, Adrianne; David, Gregory; McQualter, Jonathan L; Stripp, Barry R

    2017-07-15

    Mechanisms that regulate tissue-specific progenitors for maintenance and differentiation during development are poorly understood. Here, we demonstrate that the co-repressor protein Sin3a is crucial for lung endoderm development. Loss of Sin3a in mouse early foregut endoderm led to a specific and profound defect in lung development with lung buds failing to undergo branching morphogenesis and progressive atrophy of the proximal lung endoderm with complete epithelial loss at later stages of development. Consequently, neonatal pups died at birth due to respiratory insufficiency. Further analysis revealed that loss of Sin3a resulted in embryonic lung epithelial progenitor cells adopting a senescence-like state with permanent cell cycle arrest in G1 phase. This was mediated at least partially through upregulation of the cell cycle inhibitors Cdkn1a and Cdkn2c. At the same time, loss of endodermal Sin3a also disrupted cell differentiation of the mesoderm, suggesting aberrant epithelial-mesenchymal signaling. Together, these findings reveal that Sin3a is an essential regulator for early lung endoderm specification and differentiation. © 2017. Published by The Company of Biologists Ltd.

  14. Genome-wide mapping of Polycomb target genes unravels their roles in cell fate transitions

    DEFF Research Database (Denmark)

    Bracken, Adrian P; Dietrich, Nikolaj; Pasini, Diego

    2006-01-01

    The Polycomb group (PcG) proteins form chromatin-modifying complexes that are essential for embryonic development and stem cell renewal and are commonly deregulated in cancer. Here, we identify their target genes using genome-wide location analysis in human embryonic fibroblasts. We find that Pol...

  15. Construction of a fucoidan/laminin functional multilayer to direction vascular cell fate and promotion hemocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Changrong; Wang, Yan; Su, Hong; Yang, Ping; Huang, Nan [Key Laboratory of Advanced Materials Technology of Ministry of Education, Department of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Maitz, Manfred F. [Leibniz Institute of Polymer Research Dresden, Max Bergmann Center of Biomaterials Dresden, Dresden 01069 (Germany); Zhao, Anshan [Key Laboratory of Advanced Materials Technology of Ministry of Education, Department of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-07-01

    Surface biofunctional modification of cardiovascular stents is a versatile approach to reduce the adverse effects after implantation. In this work, a novel multifunctional coating was fabricated by coimmobilization of the sulfated polysaccharide of brown algae fucoidan and laminin to biomimic the vascular intimal conditions in order to support rapid endothelialization, prevent restenosis and improve hemocompatibility. The surface properties of the coating such as hydrophilicity, bonding density of biomolecules and stability were evaluated and optimized. According to the biocompatibility tests, the fucoidan/laminin multilayer coated surface displayed less platelet adhesion with favorable anticoagulant property. In addition, the fucoidan/laminin complex showed function to selectively regulate vascular cells growth behavior. The proliferation of endothelial cells (ECs) on the fucoidan/laminin biofunctional coating was significantly promoted. For the smooth muscle cells (SMCs), inhibitory effects on cell adhesion and proliferation were observed. In conclusion, the fucoidan/laminin biofunctional coating was successfully fabricated with desirable anticoagulant and endothelialization properties which show a promising application in the vascular devices such as vascular stents or grafts surface modification. - Highlights: • Construction of fucoidan/laminin functional multilayer to biomimic the basement membrane of vascular • The fucoidan/laminin complex demonstrates anti-coagulation property. • The fucoidan/laminin complex can selectively regulate EC and SMC growth behavior to prevent restenosis.

  16. Different Auxin Response Machineries Control Distinct Cell Fates in the Early Plant Embryo

    NARCIS (Netherlands)

    Rademacher, E.H.; Lokerse, A.S.; Schlereth, A.; Llavata Peris, C.I.; Bayer, M.; Kientz, M.; Freire Rios, A.; Borst, J.W.; Lukowitz, W.; Juergens, G.; Weijers, D.

    2012-01-01

    The cell types of the plant root are first specified early during embryogenesis and are maintained throughout plant life. Auxin plays an essential role in embryonic root initiation, in part through the action of the ARF5/MP transcription factor and its auxin-labile inhibitor IAA12/BDL. MP and BDL

  17. Epigenetic Induction of Definitive and Pancreatic Endoderm Cell Fate in Human Fibroblasts

    Directory of Open Access Journals (Sweden)

    Rangarajan Sambathkumar

    2016-01-01

    Full Text Available Reprogramming can occur by the introduction of key transcription factors (TFs as well as by epigenetic changes. We demonstrated that histone deacetylase inhibitor (HDACi Trichostatin A (TSA combined with a chromatin remodeling medium (CRM induced expression of a number of definitive endoderm and early and late pancreatic marker genes. When CRM was omitted, endoderm/pancreatic marker genes were not induced. Furthermore, treatment with DNA methyltransferase inhibitor (DNMTi 5-azacytidine (5AZA CRM did not affect gene expression changes, and when 5AZA was combined with TSA, no further increase in gene expression of endoderm, pancreatic endoderm, and endocrine markers was seen over levels induced with TSA alone. Interestingly, TSA-CRM did not affect expression of pluripotency and hepatocyte genes but induced some mesoderm transcripts. Upon removal of TSA-CRM, the endoderm/pancreatic gene expression profile returned to baseline. Our findings underscore the role epigenetic modification in transdifferentiation of one somatic cell into another. However, full reprogramming of fibroblasts to β-cells will require combination of this approach with TF overexpression and/or culture of the partially reprogrammed cells under β-cell specific conditions.

  18. Brachyury Essential for Notochord Cell Fate, Not Proliferation or EMT | Center for Cancer Research

    Science.gov (United States)

    The Brachyury or T gene encodes a transcription factor that is essential for body axis elongation during embryonic development. T is also highly expressed in chordomas, rare sarcomas derived from notochord cells, and a number of additional tumor types, including lung, prostate, and colon cancers. 

  19. Cell fate analysis of embryonic ventral mesencephalic grafts in the 6-OHDA model of Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Sonya Carvalho Neto

    Full Text Available Evidence from carefully conducted open label clinical trials suggested that therapeutic benefit can be achieved by grafting fetal dopaminergic (DAergic neurons derived from ventral mesencephalon (VM into the denervated striatum of Parkinson's disease (PD patients. However, two double-blind trials generated negative results reporting deleterious side effects such as prominent dyskinesias. Heterogeneous composition of VM grafts is likely to account for suboptimal clinical efficacy.We consider that gene expression patterns of the VM tissue needs to be better understood by comparing the genetic signature of the surviving and functioning grafts with the cell suspensions used for transplantation. In addition, it is crucial to assess whether the grafted cells exhibit the DAergic phenotype of adult substantia nigra pars compacta (SNpc. To investigate this further, we used a GFP reporter mouse as source of VM tissue that enabled the detection and dissection of the grafts 6 weeks post implantation. A comparative gene expression analysis of the VM cell suspension and grafts revealed that VM grafts continue to differentiate post-implantation. In addition, implanted grafts showed a mature SNpc-like molecular DAergic phenotype with similar expression levels of TH, Vmat2 and Dat. However, by comparing gene expression of the adult SNpc with dissected grafts we detected a higher expression of progenitor markers in the grafts. Finally, when compared to the VM cell suspension, post-grafting there was a higher expression of markers inherent to glia and other neuronal populations.In summary, our data highlight the dynamic development of distinctive DAergic and non-DAergic gene expression markers associated with the maturation of VM grafts in vivo. The molecular signature of VM grafts and its functional relevance should be further explored in future studies aimed at the optimization of DAergic cell therapy approaches in PD.

  20. Prion replication occurs in endogenous adult neural stem cells and alters their neuronal fate: involvement of endogenous neural stem cells in prion diseases.

    Directory of Open Access Journals (Sweden)

    Aroa Relaño-Ginès

    Full Text Available Prion diseases are irreversible progressive neurodegenerative diseases, leading to severe incapacity and death. They are characterized in the brain by prion amyloid deposits, vacuolisation, astrocytosis, neuronal degeneration, and by cognitive, behavioural and physical impairments. There is no treatment for these disorders and stem cell therapy therefore represents an interesting new approach. Gains could not only result from the cell transplantation, but also from the stimulation of endogenous neural stem cells (NSC or by the combination of both approaches. However, the development of such strategies requires a detailed knowledge of the pathology, particularly concerning the status of the adult neurogenesis and endogenous NSC during the development of the disease. During the past decade, several studies have consistently shown that NSC reside in the adult mammalian central nervous system (CNS and that adult neurogenesis occurs throughout the adulthood in the subventricular zone of the lateral ventricle or the Dentate Gyrus of the hippocampus. Adult NSC are believed to constitute a reservoir for neuronal replacement during normal cell turnover or after brain injury. However, the activation of this system does not fully compensate the neuronal loss that occurs during neurodegenerative diseases and could even contribute to the disease progression. We investigated here the status of these cells during the development of prion disorders. We were able to show that NSC accumulate and replicate prions. Importantly, this resulted in the alteration of their neuronal fate which then represents a new pathologic event that might underlie the rapid progression of the disease.

  1. Chronic inflammation imposes aberrant cell fate in regenerating epithelia through mechanotransduction.

    Science.gov (United States)

    Nowell, Craig S; Odermatt, Pascal D; Azzolin, Luca; Hohnel, Sylke; Wagner, Erwin F; Fantner, Georg E; Lutolf, Matthias P; Barrandon, Yann; Piccolo, Stefano; Radtke, Freddy

    2016-02-01

    Chronic inflammation is associated with a variety of pathological conditions in epithelial tissues, including cancer, metaplasia and aberrant wound healing. In relation to this, a significant body of evidence suggests that aberration of epithelial stem and progenitor cell function is a contributing factor in inflammation-related disease, although the underlying cellular and molecular mechanisms remain to be fully elucidated. In this study, we have delineated the effect of chronic inflammation on epithelial stem/progenitor cells using the corneal epithelium as a model tissue. Using a combination of mouse genetics, pharmacological approaches and in vitro assays, we demonstrate that chronic inflammation elicits aberrant mechanotransduction in the regenerating corneal epithelium. As a consequence, a YAP-TAZ/β-catenin cascade is triggered, resulting in the induction of epidermal differentiation on the ocular surface. Collectively, the results of this study demonstrate that chronic inflammation and mechanotransduction are linked and act to elicit pathological responses in regenerating epithelia.

  2. In one harness: the interplay of cellular responses and subsequent cell fate after quantum dot uptake

    KAUST Repository

    Gladkovskaya, Olga

    2016-09-13

    Rapid growth and expansion of engineered nanomaterials will occur when the technology can be used safely. Quantum dots have excellent prospects in clinical applications, but the issue of toxicity has not yet been resolved. To enable their medical implementation, the effect on, and mechanisms in, live cells should be clearly known and predicted. A massive amount of experimental data dedicated to nanotoxicity has been accumulated to-date, but it lacks a logical structure. The current challenge is to organize existing knowledge into lucid biological and mathematical models. In our review we aim to describe the interplay of various cell death mechanisms triggered by quantum dots as a consequence of particle parameters and experimental conditions.

  3. Upon impact: the fate of adhering Pseudomonas fluorescens cells during nanofiltration.

    Science.gov (United States)

    Habimana, Olivier; Semião, Andrea J C; Casey, Eoin

    2014-08-19

    Nanofiltration (NF) is a high-pressure membrane filtration process increasingly applied in drinking water treatment and water reuse processes. NF typically rejects divalent salts, organic matter, and micropollutants. However, the efficiency of NF is adversely affected by membrane biofouling, during which microorganisms adhere to the membrane and proliferate to create a biofilm. Here we show that adhered Pseudomonas fluorescens cells under high permeate flux conditions are met with high fluid shear and convective fluxes at the membrane-liquid interface, resulting in their structural damage and collapse. These results were confirmed by fluorescent staining, flow cytometry, and scanning electron microscopy. This present study offers a "first-glimpse" of cell damage and death during the initial phases of bacterial adhesion to NF membranes and raises a key question about the role of this observed phenomena during early-stage biofilm formation under permeate flux and cross-flow conditions.

  4. SHP2 regulates chondrocyte terminal differentiation, growth plate architecture and skeletal cell fates.

    Directory of Open Access Journals (Sweden)

    Margot E Bowen

    Full Text Available Loss of PTPN11/SHP2 in mice or in human metachondromatosis (MC patients causes benign cartilage tumors on the bone surface (exostoses and within bones (enchondromas. To elucidate the mechanisms underlying cartilage tumor formation, we investigated the role of SHP2 in the specification, maturation and organization of chondrocytes. Firstly, we studied chondrocyte maturation by performing RNA-seq on primary chondrocyte pellet cultures. We found that SHP2 depletion, or inhibition of the ERK1/2 pathway, delays the terminal differentiation of chondrocytes from the early-hypertrophic to the late-hypertrophic stage. Secondly, we studied chondrocyte maturation and organization in mice with a mosaic postnatal inactivation of Ptpn11 in chondrocytes. We found that the vertebral growth plates of these mice have expanded domains of early-hypertrophic chondrocytes that have not yet terminally differentiated, and their enchondroma-like lesions arise from chondrocytes displaced from the growth plate due to a disruption in the organization of maturation and ossification zones. Furthermore, we observed that lesions from human MC patients also display disorganized chondrocyte maturation zones. Next, we found that inactivation of Ptpn11 in Fsp1-Cre-expressing fibroblasts induces exostosis-like outgrowths, suggesting that loss of SHP2 in cells on the bone surface and at bone-ligament attachment sites induces ectopic chondrogenesis. Finally, we performed lineage tracing to show that exostoses and enchondromas in mice likely contain mixtures of wild-type and SHP2-deficient chondrocytes. Together, these data indicate that in patients with MC, who are heterozygous for inherited PTPN11 loss-of-function mutations, second-hit mutations in PTPN11 can induce enchondromas by disrupting the organization and delaying the terminal differentiation of growth plate chondrocytes, and can induce exostoses by causing ectopic chondrogenesis of cells on the bone surface. Furthermore, the

  5. Oncogene-Induced Changes in Mammary Cell Fate and EMT in Breast Tumorigenesis

    Science.gov (United States)

    2015-04-01

    Snail shRNA (n=125) b. Serial dilution injection into NOD SCID mammary glands with weekly palpation This task is to test the in-vivo tumor initiating...Subaim1a d. Serial dilution injection into NOD SCID mammary glands with weekly palpation As stated above, the HMEC cells are ready and testing has begun...experimental techniques . These optimization experiments are all outlined below. As demonstrated in Aim 1b, we have successfully cloned CD8IGF1R into

  6. The function of chromatin modifiers in lineage commitment and cell fate specification.

    Science.gov (United States)

    Signolet, Jason; Hendrich, Brian

    2015-05-01

    Proteins that modify the structure of chromatin are known to be important for various aspects of metazoan biology including development, disease and possibly ageing. Yet functional details of why these proteins are important, i.e. how their action influences a given biological process, are lacking. While it is now possible to describe the biochemistry of how these proteins remodel chromatin, their chromatin binding profiles in cell lines, or gene expression changes upon loss of a given protein, in very few cases has this easily translated into an understanding of how the function of that protein actually influences a developmental process. Given that many chromatin modifying proteins will largely exert their influence through control of gene expression, it is useful to consider developmental processes as changes in the gene regulatory network (GRN), with each cell type exhibiting a unique gene expression profile. In this essay we consider the impact of two abundant and highly conserved chromatin modifying complexes, namely the nucleosome remodelling and deacetylation (NuRD) complex and the polycomb repressive complex 2 (PRC2), on the change in GRNs associated with lineage commitment during early mammalian development. We propose that while the NuRD complex limits the stability of cell states and defines the developmental trajectory between two stable states, PRC2 activity is important for stabilizing a new GRN once established. Although these two complexes display different biochemical activities, chromatin binding profiles and mutant phenotypes, we propose a model to explain how they cooperate to facilitate the transition through cell states that is development. © 2014 The Authors. FEBS Journal published by John Wiley & Sons Ltd on behalf of FEBS.

  7. Legumain Regulates Differentiation Fate of Human Bone Marrow Stromal Cells and Is Altered in Postmenopausal Osteoporosis.

    Science.gov (United States)

    Jafari, Abbas; Qanie, Diyako; Andersen, Thomas L; Zhang, Yuxi; Chen, Li; Postert, Benno; Parsons, Stuart; Ditzel, Nicholas; Khosla, Sundeep; Johansen, Harald Thidemann; Kjærsgaard-Andersen, Per; Delaisse, Jean-Marie; Abdallah, Basem M; Hesselson, Daniel; Solberg, Rigmor; Kassem, Moustapha

    2017-02-14

    Secreted factors are a key component of stem cell niche and their dysregulation compromises stem cell function. Legumain is a secreted cysteine protease involved in diverse biological processes. Here, we demonstrate that legumain regulates lineage commitment of human bone marrow stromal cells and that its expression level and cellular localization are altered in postmenopausal osteoporotic patients. As shown by genetic and pharmacological manipulation, legumain inhibited osteoblast (OB) differentiation and in vivo bone formation through degradation of the bone matrix protein fibronectin. In addition, genetic ablation or pharmacological inhibition of legumain activity led to precocious OB differentiation and increased vertebral mineralization in zebrafish. Finally, we show that localized increased expression of legumain in bone marrow adipocytes was inversely correlated with adjacent trabecular bone mass in a cohort of patients with postmenopausal osteoporosis. Our data suggest that altered proteolytic activity of legumain in the bone microenvironment contributes to decreased bone mass in postmenopausal osteoporosis. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  8. Dynamic regulation of EZH2 from HPSc to hepatocyte-like cell fate.

    Science.gov (United States)

    Pistoni, Mariaelena; Helsen, Nicky; Vanhove, Jolien; Boon, Ruben; Xu, Zhuofei; Ordovas, Laura; Verfaillie, Catherine M

    2017-01-01

    Currently, drug metabolization and toxicity studies rely on the use of primary human hepatocytes and hepatoma cell lines, which both have conceivable limitations. Human pluripotent stem cell (hPSC)-derived hepatocyte-like cells (HLCs) are an alternative and valuable source of hepatocytes that can overcome these limitations. EZH2 (enhancer of zeste homolog 2), a transcriptional repressor of the polycomb repressive complex 2 (PRC2), may play an important role in hepatocyte development, but its role during in vitro hPSC-HLC differentiation has not yet been assessed. We here demonstrate dynamic regulation of EZH2 during hepatic differentiation of hPSC. To enhance EZH2 expression, we inducibly overexpressed EZH2 between d0 and d8, demonstrating a significant improvement in definitive endoderm formation, and improved generation of HLCs. Despite induction of EZH2 overexpression until d8, EZH2 transcript and protein levels decreased from d4 onwards, which might be caused by expression of microRNAs predicted to inhibit EZH2 expression. In conclusion, our studies demonstrate that EZH2 plays a role in endoderm formation and hepatocyte differentiation, but its expression is tightly post-transcriptionally regulated during this process.

  9. The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity

    Science.gov (United States)

    Sundaram, Meera V.; Buechner, Matthew

    2016-01-01

    The excretory system of the nematode Caenorhabditis elegans is a superb model of tubular organogenesis involving a minimum of cells. The system consists of just three unicellular tubes (canal, duct, and pore), a secretory gland, and two associated neurons. Just as in more complex organs, cells of the excretory system must first adopt specific identities and then coordinate diverse processes to form tubes of appropriate topology, shape, connectivity, and physiological function. The unicellular topology of excretory tubes, their varied and sometimes complex shapes, and the dynamic reprogramming of cell identity and remodeling of tube connectivity that occur during larval development are particularly fascinating features of this organ. The physiological roles of the excretory system in osmoregulation and other aspects of the animal’s life cycle are only beginning to be explored. The cellular mechanisms and molecular pathways used to build and shape excretory tubes appear similar to those used in both unicellular and multicellular tubes in more complex organs, such as the vertebrate vascular system and kidney, making this simple organ system a useful model for understanding disease processes. PMID:27183565

  10. Impacting tumor cell-fate by targeting the inhibitor of apoptosis protein survivin

    Directory of Open Access Journals (Sweden)

    Janik John E

    2011-04-01

    Full Text Available Abstract Survivin (BIRC5, a member of the inhibitor of apoptosis protein (IAP family that inhibits caspases and blocks cell death is highly expressed in cancer and is associated with a poorer clinical outcome. Functioning simultaneously during cell division and apoptosis inhibition, survivin plays a pivotal role in determining cell survival. Survivin has consistently been identified by molecular profiling analysis to be associated with higher tumor grade, more advanced disease, abbreviated survival, accelerated rates of recurrence, and chemotherapy and radiation resistance. Survivin's differential expression in cancer compared to normal tissue and its role as a nodal protein in a number of cellular pathways make it a highly flexible therapeutic target, suitable for small-molecule inhibitiors, molecular antagonists, and vaccination-based therapies. By targeting survivin it is hoped that multiple tumor signaling circuitries may be simultaneously disabled. This effect may be applicable to many tumor histologies irrespective of specific genetic makeup. To date, survivin inhibitors have shown modest activity as single agents, but it is anticipated that when given in combination with cytotoxic chemotherapy or monoclonal antibodies they may exhibit enhanced efficacy. This review discusses the complex circuitry of survivin in human cancers and highlights clinical trials involving novel agents that target this important protein.

  11. Perlecan expression influences the keratin 15-positive cell population fate in the epidermis of aging skin.

    Science.gov (United States)

    Dos Santos, Morgan; Michopoulou, Anna; André-Frei, Valérie; Boulesteix, Sophie; Guicher, Christine; Dayan, Guila; Whitelock, John; Damour, Odile; Rousselle, Patricia

    2016-04-01

    The epidermis is continuously renewed by stem cell proliferation and differentiation. Basal keratinocytes append the dermal-epidermal junction, a cell surface-associated, extracellular matrix that provides structural support and influences their behaviour. It consists of laminins, type IV collagen, nidogens, and perlecan, which are necessary for tissue organization and structural integrity. Perlecan is a heparan sulfate proteoglycan known to be involved in keratinocyte survival and differentiation. Aging affects the dermal epidermal junction resulting in decreased contact with keratinocytes, thus impacting epidermal renewal and homeostasis. We found that perlecan expression decreased during chronological skin aging. Our in vitro studies revealed reduced perlecan transcript levels in aged keratinocytes. The production of in vitro skin models revealed that aged keratinocytes formed a thin and poorly organized epidermis. Supplementing these models with purified perlecan reversed the phenomenon allowing restoration of a well-differentiated multi-layered epithelium. Perlecan down-regulation in cultured keratinocytes caused depletion of the cell population that expressed keratin 15. This phenomenon depended on the perlecan heparan sulphate moieties, which suggested the involvement of a growth factor. Finally, we found defects in keratin 15 expression in the epidermis of aging skin. This study highlighted a new role for perlecan in maintaining the self-renewal capacity of basal keratinocytes.

  12. Fate of tumor cells injected into left ventricle of heart in BALB/c mice: role of natural killer cells

    DEFF Research Database (Denmark)

    Basse, P; Hokland, P; Heron, I

    1988-01-01

    extent, the bone, skin, and muscle. The only organs that could arrest the LV-injected tumor cells were the lungs and the liver. In the lungs clearance of YAC-1 cells began immediately after the cells were arrested. However, the rate of clearance could be almost abrogated by pretreatment of the recipients...... with anti-asialo GM1 antiserum, which destroys most of the NK cells in vivo and strongly depresses the in vitro NK cell activity. In contrast, YAC-1 cells arrested in the liver were not cleared from this organ during the first 1-2 hours after arrest. After this delay clearance of the cells commenced....... Pretreatment of the recipients with anti-asialo GM1 also strongly depressed the clearance of tumor cells from the liver. Although pretreatment with polyinosinic-polycytidylic acid enhanced in vitro NK cell activity, it could augment only slightly the clearance of YAC-1 cells from the lungs and the liver. Thus...

  13. The homeobox gene Gsx2 regulates the self-renewal and differentiation of neural stem cells and the cell fate of postnatal progenitors.

    Directory of Open Access Journals (Sweden)

    Héctor R Méndez-Gómez

    Full Text Available The Genetic screened homeobox 2 (Gsx2 transcription factor is required for the development of olfactory bulb (OB and striatal neurons, and for the regional specification of the embryonic telencephalon. Although Gsx2 is expressed abundantly by progenitor cells in the ventral telencephalon, its precise function in the generation of neurons from neural stem cells (NSCs is not clear. Similarly, the role of Gsx2 in regulating the self-renewal and multipotentiality of NSCs has been little explored. Using retroviral vectors to express Gsx2, we have studied the effect of Gsx2 on the growth of NSCs isolated from the OB and ganglionic eminences (GE, as well as its influence on the proliferation and cell fate of progenitors in the postnatal mouse OB. Expression of Gsx2 reduces proliferation and the self-renewal capacity of NSCs, without significantly affecting cell death. Furthermore, Gsx2 overexpression decreases the differentiation of NSCs into neurons and glia, and it maintains the cells that do not differentiate as cycling progenitors. These effects were stronger in GESCs than in OBSCs, indicating that the actions of Gsx2 are cell-dependent. In vivo, Gsx2 produces a decrease in the number of Pax6+ cells and doublecortin+ neuroblasts, and an increase in Olig2+ cells. In summary, our findings show that Gsx2 inhibits the ability of NSCs to proliferate and self-renew, as well as the capacity of NSC-derived progenitors to differentiate, suggesting that this transcription factor regulates the quiescent and undifferentiated state of NSCs and progenitors. Furthermore, our data indicate that Gsx2 negatively regulates neurogenesis from postnatal progenitor cells.

  14. Transcription factor retention on mitotic chromosomes: regulatory mechanisms and impact on cell fate decisions.

    Science.gov (United States)

    Raccaud, Mahé; Suter, David M

    2017-09-01

    During mitosis, gene transcription stops, and the bulk of DNA-binding proteins are excluded from condensed chromosomes. While most gene-specific transcription factors are largely evicted from mitotic chromosomes, a subset remains bound to specific and non-specific DNA sites. Here, we review the current knowledge on the mechanisms leading to the retention of a subset of transcription factors on mitotic chromosomes and discuss the implications in gene expression regulation and their potential as an epigenetic mechanism controlling stem cell self-renewal and differentiation. © 2017 Federation of European Biochemical Societies.

  15. Stat3 signaling regulates embryonic stem cell fate in a dose-dependent manner

    Directory of Open Access Journals (Sweden)

    Chih-I Tai

    2014-09-01

    Full Text Available Stat3 is essential for mouse embryonic stem cell (mESC self-renewal mediated by LIF/gp130 receptor signaling. Current understanding of Stat3-mediated ESC self-renewal mechanisms is very limited, and has heretofore been dominated by the view that Stat3 signaling functions in a binary “on/off” manner. Here, in contrast to this binary viewpoint, we demonstrate a contextual, rheostat-like mechanism for Stat3's function in mESCs. Activation and expression levels determine whether Stat3 functions in a self-renewal or a differentiation role in mESCs. We also show that Stat3 induces rapid differentiation of mESCs toward the trophectoderm (TE lineage when its activation level exceeds certain thresholds. Stat3 induces this differentiation phenotype via induction of Tfap2c and its downstream target Cdx2. Our findings provide a novel concept in the realm of Stat3, self-renewal signaling, and pluripotent stem cell biology. Ultimately, this finding may facilitate the development of conditions for the establishment of authentic non-rodent ESCs.

  16. p66Shc Aging Protein in Control of Fibroblasts Cell Fate

    Directory of Open Access Journals (Sweden)

    Mariusz R. Wieckowski

    2011-08-01

    Full Text Available Reactive oxygen species (ROS are wieldy accepted as one of the main factors of the aging process. These highly reactive compounds modify nucleic acids, proteins and lipids and affect the functionality of mitochondria in the first case and ultimately of the cell. Any agent or genetic modification that affects ROS production and detoxification can be expected to influence longevity. On the other hand, genetic manipulations leading to increased longevity can be expected to involve cellular changes that affect ROS metabolism. The 66-kDa isoform of the growth factor adaptor Shc (p66Shc has been recognized as a relevant factor to the oxygen radical theory of aging. The most recent data indicate that p66Shc protein regulates life span in mammals and its phosphorylation on serine 36 is important for the initiation of cell death upon oxidative stress. Moreover, there is strong evidence that apart from aging, p66Shc may be implicated in many oxidative stress-associated pathologies, such as diabetes, mitochondrial and neurodegenerative disorders and tumorigenesis. This article summarizes recent knowledge about the role of p66Shc in aging and senescence and how this protein can influence ROS production and detoxification, focusing on studies performed on skin and skin fibroblasts.

  17. RXR heterodimers orchestrate transcriptional control of neurogenesis and cell fate specification.

    Science.gov (United States)

    Simandi, Zoltan; Horvath, Attila; Cuaranta-Monroy, Ixchelt; Sauer, Sascha; Deleuze, Jean-Francois; Nagy, Laszlo

    2017-08-02

    Retinoid X Receptors (RXRs) are unique and enigmatic members of the nuclear receptor (NR) family with extensive and complex biological functions in cellular differentiation. On the one hand, RXRs through permissive heterodimerization with other NRs are able to integrate multiple lipid signaling pathways and are believed to play a central role to coordinate the development of the central nervous system. On the other hand, RXRs may have heterodimer-independent functions as well. Therefore, a more RXR-centric analysis is warranted to identify its genomic binding sites and regulated gene networks, which are orchestrating the earliest events in neuronal differentiation. Recently developed genome-wide approaches allow systematic analyses of the RXR-driven neural differentiation. Here we applied next generation sequencing-based methodology to track the dynamic redistribution of the RXR cistrome along the path of embryonic stem cell to glutamatergic neuron differentiation. We identified Retinoic Acid Receptor (RAR) and Liver X Receptor (LXR) as dominant heterodimeric partners of RXR in these cellular stages. Our data presented here characterize the RAR:RXR and LXR:RXR-mediated transcriptional program in embryonic stem cells, neural progenitors and terminally differentiated neurons. Considering the growing evidence for dysregulated RXR-mediated signaling in neurodegenerative disorders, such as Alzheimer's Disease or Amyotrophic Lateral Sclerosis, the data presented here will be also a valuable resource for the field of neuro(patho)biology. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Genome-wide interrogation of Mammalian stem cell fate determinants by nested chromosome deletions.

    Directory of Open Access Journals (Sweden)

    Simon Fortier

    2010-12-01

    Full Text Available Understanding the function of important DNA elements in mammalian stem cell genomes would be enhanced by the availability of deletion collections in which segmental haploidies are precisely characterized. Using a modified Cre-loxP-based system, we now report the creation and characterization of a collection of ∼1,300 independent embryonic stem cell (ESC clones enriched for nested chromosomal deletions. Mapping experiments indicate that this collection spans over 25% of the mouse genome with good representative coverage of protein-coding genes, regulatory RNAs, and other non-coding sequences. This collection of clones was screened for in vitro defects in differentiation of ESC into embryoid bodies (EB. Several putative novel haploinsufficient regions, critical for EB development, were identified. Functional characterization of one of these regions, through BAC complementation, identified the ribosomal gene Rps14 as a novel haploinsufficient determinant of embryoid body formation. This new library of chromosomal deletions in ESC (DelES: http://bioinfo.iric.ca/deles will serve as a unique resource for elucidation of novel protein-coding and non-coding regulators of ESC activity.

  19. Genome-wide interrogation of Mammalian stem cell fate determinants by nested chromosome deletions.

    Science.gov (United States)

    Fortier, Simon; Bilodeau, Mélanie; Macrae, Tara; Laverdure, Jean-Philippe; Azcoitia, Valeria; Girard, Simon; Chagraoui, Jalila; Ringuette, Nancy; Hébert, Josée; Krosl, Jana; Mayotte, Nadine; Sauvageau, Guy

    2010-12-09

    Understanding the function of important DNA elements in mammalian stem cell genomes would be enhanced by the availability of deletion collections in which segmental haploidies are precisely characterized. Using a modified Cre-loxP-based system, we now report the creation and characterization of a collection of ∼1,300 independent embryonic stem cell (ESC) clones enriched for nested chromosomal deletions. Mapping experiments indicate that this collection spans over 25% of the mouse genome with good representative coverage of protein-coding genes, regulatory RNAs, and other non-coding sequences. This collection of clones was screened for in vitro defects in differentiation of ESC into embryoid bodies (EB). Several putative novel haploinsufficient regions, critical for EB development, were identified. Functional characterization of one of these regions, through BAC complementation, identified the ribosomal gene Rps14 as a novel haploinsufficient determinant of embryoid body formation. This new library of chromosomal deletions in ESC (DelES: http://bioinfo.iric.ca/deles) will serve as a unique resource for elucidation of novel protein-coding and non-coding regulators of ESC activity.

  20. CHD1 regulates cell fate determination by activation of differentiation-induced genes

    DEFF Research Database (Denmark)

    Baumgart, Simon J; Najafova, Zeynab; Hossan, Tareq

    2017-01-01

    The coordinated temporal and spatial activation of gene expression is essential for proper stem cell differentiation. The Chromodomain Helicase DNA-binding protein 1 (CHD1) is a chromatin remodeler closely associated with transcription and nucleosome turnover downstream of the transcriptional start...... site (TSS). In this study, we show that CHD1 is required for the induction of osteoblast-specific gene expression, extracellular-matrix mineralization and ectopic bone formation in vivo. Genome-wide occupancy analyses revealed increased CHD1 occupancy around the TSS of differentiation-activated genes....... Furthermore, we observed that CHD1-dependent genes are mainly induced during osteoblast differentiation and are characterized by higher levels of CHD1 occupancy around the TSS. Interestingly, CHD1 depletion resulted in increased pausing of RNA Polymerase II (RNAPII) and decreased H2A.Z occupancy close...

  1. Regulation of Cell Fate Determination by Single-Repeat R3 MYB Transcription Factors in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shucai [Northeast Normal University, Changchun, China; Chen, Jay [ORNL

    2014-01-01

    MYB transcription factors regulate multiple aspects of plant growth and development. Among the large family of MYB transcription factors, single-repeat R3 MYB are characterized by their short sequence (<120 amino acids) consisting largely of the single MYB DNA-binding repeat. In the model plant Arabidopsis, R3 MYBs mediate lateral inhibition during epidermal patterning and are best characterized for their regulatory roles in trichome and root hair development. R3 MYBs act as negative regulators for trichome formation but as positive regulators for root hair development. In this article, we provide a comprehensive review on the role of R3 MYBs in the regulation of cell type specification in the model plant Arabidopsis.

  2. Differentially activated macrophages orchestrate myogenic precursor cell fate during human skeletal muscle regeneration

    DEFF Research Database (Denmark)

    Saclier, Marielle; Yacoub-Youssef, Houda; Mackey, Abigail

    2013-01-01

    , we explored both in vitro and in vivo, in human, the interactions of differentially activated MPs with myogenic precursor cells (MPCs) during adult myogenesis and skeletal muscle regeneration. We showed in vitro that through the differential secretion of cytokines and growth factors, proinflammatory...... MPs inhibited MPC fusion while anti-inflammatory MPs strongly promoted MPC differentiation by increasing their commitment into differentiated myocytes and the formation of mature myotubes. Furthermore, the in vivo time course of expression of myogenic and MP markers was studied in regenerating human...... healthy muscle after damage. We observed that regenerating areas containing proliferating MPCs were preferentially associated with MPs expressing proinflammatory markers. In the same muscle, regenerating areas containing differentiating myogenin-positive MPCs were preferentially coupled to MPs harboring...

  3. Reduced reactivation from dormancy but maintained lineage choice of human mesenchymal stem cells with donor age.

    Directory of Open Access Journals (Sweden)

    Verena Dexheimer

    Full Text Available UNLABELLED: Mesenchymal stem cells (MSC are promising for cell-based regeneration therapies but up to date it is still controversial whether their function is maintained throughout ageing. Aim of this study was to address whether frequency, activation in vitro, replicative function, and in vitro lineage choice of MSC is maintained throughout ageing to answer the question whether MSC-based regeneration strategies should be restricted to younger individuals. MSC from bone marrow aspirates of 28 donors (5-80 years were characterized regarding colony-forming unit-fibroblast (CFU-F numbers, single cell cloning efficiency (SSCE, osteogenic, adipogenic and chondrogenic differentiation capacity in vitro. Alkaline phosphatase (ALP activity, mineralization, Oil Red O content, proteoglycan- and collagen type II deposition were quantified. While CFU-F frequency was maintained, SSCE and early proliferation rate decreased significantly with advanced donor age. MSC with higher proliferation rate before start of induction showed stronger osteogenic, adipogenic and chondrogenic differentiation. MSC with high osteogenic capacity underwent better chondrogenesis and showed a trend to better adipogenesis. Lineage choice was, however, unaltered with age. CONCLUSION: Ageing influenced activation from dormancy and replicative function of MSC in a way that it may be more demanding to mobilize MSC to fast cell growth at advanced age. Since fast proliferation came along with high multilineage capacity, the proliferation status of expanded MSC rather than donor age may provide an argument to restrict MSC-based therapies to certain individuals.

  4. Differential regulation of H3S10 phosphorylation, mitosis progression and cell fate by Aurora Kinase B and C in mouse preimplantation embryos

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    Wenzhi Li

    2017-04-01

    Full Text Available ABSTRACT Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B (AurkB is ubiquitously expressed while Aurora kinase C (AurkC is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 (H3S10P and regulate metaphase timing. Using an Oct4-photoactivatable GFP fusion protein (Oct4-paGFP and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.

  5. Effects of permeability and living space on cell fate and neo-tissue development in hydrogel-based scaffolds: a study with cartilaginous model.

    Science.gov (United States)

    Fan, Changjiang; Wang, Dong-An

    2015-04-01

    One bottleneck in tissue regeneration with hydrogel scaffolds is the limited understanding of the crucial factors for controlling hydrogel's physical microenvironments to regulate cell fate. Here, the effects of permeability and living space of hydrogels on encapsulated cells' behavior were evaluated, respectively. Three model hydrogel-based constructs are fabricated by using photo-crosslinkable hyaluronic acid as precursor and chondrocytes as model cell type. The better permeable hydrogels facilitate better cell viability and rapid proliferation, which lead to increased production of extracellular matrix (ECM), e.g. collagen, glycosaminoglycan. By prolonged culture, nano-sized hydrogel networks inhibit neo-tissue development, and the presence of macro-porous living spaces significantly enhance ECM deposition via forming larger cell clusters and eventually induce formation of scaffold-free neo-tissue islets. The results of this work demonstrate that the manipulation and optimization of hydrogel microenvironments, namely permeability and living space, are crucial to direct cell fate and neo-tissue formation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Endoplasmic Reticulum Stress and Oxidative Stress in Cell Fate Decision and Human Disease

    Science.gov (United States)

    Cao, Stewart Siyan

    2014-01-01

    Abstract Significance: The endoplasmic reticulum (ER) is a specialized organelle for the folding and trafficking of proteins, which is highly sensitive to changes in intracellular homeostasis and extracellular stimuli. Alterations in the protein-folding environment cause accumulation of misfolded proteins in the ER that profoundly affect a variety of cellular signaling processes, including reduction–oxidation (redox) homeostasis, energy production, inflammation, differentiation, and apoptosis. The unfolded protein response (UPR) is a collection of adaptive signaling pathways that evolved to resolve protein misfolding and restore an efficient protein-folding environment. Recent Advances: Production of reactive oxygen species (ROS) has been linked to ER stress and the UPR. ROS play a critical role in many cellular processes and can be produced in the cytosol and several organelles, including the ER and mitochondria. Studies suggest that altered redox homeostasis in the ER is sufficient to cause ER stress, which could, in turn, induce the production of ROS in the ER and mitochondria. Critical Issues: Although ER stress and oxidative stress coexist in many pathologic states, whether and how these stresses interact is unknown. It is also unclear how changes in the protein-folding environment in the ER cause oxidative stress. In addition, how ROS production and protein misfolding commit the cell to an apoptotic death and contribute to various degenerative diseases is unknown. Future Directions: A greater fundamental understanding of the mechanisms that preserve protein folding homeostasis and redox status will provide new information toward the development of novel therapeutics for many human diseases. Antioxid. Redox Signal. 21, 396–413. PMID:24702237

  7. Impact of implementation choices on quantitative predictions of cell-based computational models

    Science.gov (United States)

    Kursawe, Jochen; Baker, Ruth E.; Fletcher, Alexander G.

    2017-09-01

    'Cell-based' models provide a powerful computational tool for studying the mechanisms underlying the growth and dynamics of biological tissues in health and disease. An increasing amount of quantitative data with cellular resolution has paved the way for the quantitative parameterisation and validation of such models. However, the numerical implementation of cell-based models remains challenging, and little work has been done to understand to what extent implementation choices may influence model predictions. Here, we consider the numerical implementation of a popular class of cell-based models called vertex models, which are often used to study epithelial tissues. In two-dimensional vertex models, a tissue is approximated as a tessellation of polygons and the vertices of these polygons move due to mechanical forces originating from the cells. Such models have been used extensively to study the mechanical regulation of tissue topology in the literature. Here, we analyse how the model predictions may be affected by numerical parameters, such as the size of the time step, and non-physical model parameters, such as length thresholds for cell rearrangement. We find that vertex positions and summary statistics are sensitive to several of these implementation parameters. For example, the predicted tissue size decreases with decreasing cell cycle durations, and cell rearrangement may be suppressed by large time steps. These findings are counter-intuitive and illustrate that model predictions need to be thoroughly analysed and implementation details carefully considered when applying cell-based computational models in a quantitative setting.

  8. "I overcame fate, fate harkens to me"

    Directory of Open Access Journals (Sweden)

    Jan Bergman

    1967-02-01

    Full Text Available ”I overcome Fate (to heimarmenon; Fate harkens to me". In order to understand the tension in this proclamation of Isis, which forms the conclusion of the Isis aretalogy from Cyme, we must make a closer acquaintance with the two dramatis personae. With what right could Isis make a claim like this? How was to heimarmenon understood and experienced in the Hellenistic environment to which the Cyme hymn belongs? This paper considers the Egyptian goddess and her relation to Fate, by pointing out a few `fatalistic traits' in Isis' character. But first we have to ask another question: How did the Egyptians understand Fate in general? What concepts did they use in order to define Fate and its effects? What was the relation between the god(s and Fate?

  9. Bioreactors to influence stem cell fate: augmentation of mesenchymal stem cell signaling pathways via dynamic culture systems.

    Science.gov (United States)

    Yeatts, Andrew B; Choquette, Daniel T; Fisher, John P

    2013-02-01

    Mesenchymal stem cells (MSCs) are a promising cell source for bone and cartilage tissue engineering as they can be easily isolated from the body and differentiated into osteoblasts and chondrocytes. A cell based tissue engineering strategy using MSCs often involves the culture of these cells on three-dimensional scaffolds; however the size of these scaffolds and the cell population they can support can be restricted in traditional static culture. Thus dynamic culture in bioreactor systems provides a promising means to culture and differentiate MSCs in vitro. This review seeks to characterize key MSC differentiation signaling pathways and provides evidence as to how dynamic culture is augmenting these pathways. Following an overview of dynamic culture systems, discussion will be provided on how these systems can effectively modify and maintain important culture parameters including oxygen content and shear stress. Literature is reviewed for both a highlight of key signaling pathways and evidence for regulation of these signaling pathways via dynamic culture systems. The ability to understand how these culture systems are affecting MSC signaling pathways could lead to a shear or oxygen regime to direct stem cell differentiation. In this way the efficacy of in vitro culture and differentiation of MSCs on three-dimensional scaffolds could be greatly increased. Bioreactor systems have the ability to control many key differentiation stimuli including mechanical stress and oxygen content. The further integration of cell signaling investigations within dynamic culture systems will lead to a quicker realization of the promise of tissue engineering and regenerative medicine. This article is part of a Special Issue entitled Biochemistry of Stem Cells. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Bioreactors to Influence Stem Cell Fate: Augmentation of Mesenchymal Stem Cell Signaling Pathways via Dynamic Culture Systems

    Science.gov (United States)

    Yeatts, Andrew B.; Choquette, Daniel T.; Fisher, John P.

    2012-01-01

    Background Mesenchymal stem cells (MSCs) are a promising cell source for bone and cartilage tissue engineering as they can be easily isolated from the body and differentiated into osteoblasts and chondrocytes. A cell based tissue engineering strategy using MSCs often involves the culture of these cells on three-dimensional scaffolds; however the size of these scaffolds and the cell population they can support can be restricted in traditional static culture. Thus dynamic culture in bioreactor systems provides a promising means to culture and differentiate MSCs in vitro. Scope of Review This review seeks to characterize key MSC differentiation signaling pathways and provides evidence as to how dynamic culture is augmenting these pathways. Following an overview of dynamic culture systems, discussion will be provided on how these systems can effectively modify and maintain important culture parameters including oxygen content and shear stress. Literature is reviewed for both a highlight of key signaling pathways and evidence for regulation of these signaling pathways via dynamic culture systems. Major Conclusions The ability to understand how these culture systems are affecting MSC signaling pathways could lead to a shear or oxygen regime to direct stem cell differentiation. In this way the efficacy of in vitro culture and differentiation of MSCs on three-dimensional scaffolds could be greatly increased. General Significance Bioreactor systems have the ability to control many key differentiation stimuli including mechanical stress and oxygen content. The further integration of cell signaling investigations within dynamic culture systems will lead to a quicker realization of the promise of tissue engineering and regenerative medicine. PMID:22705676

  11. Fate and effect of ingested Bacillus cereus spores and vegetative cells in the intestinal tract of human-flora-associated rats

    DEFF Research Database (Denmark)

    Wilcks, Andrea; Hansen, Bjarne Munk; Hendriksen, Niels Bohse

    2006-01-01

    gradient gel electrophoresis analysis with universal 16S rRNA gene primers revealed significant changes in the intestinal microbiota of animals dosed with spores. Vero cell assays and a commercial kit (BCET-RPLA) did not reveal any enterotoxin production from B. cereus F4433/73R in the intestinal tract.......The fate and effect of Bacillus cereus F4433/73R in the intestine of human-flora-associated rats was studied using bacteriological culturing techniques and PCR-denaturing gradient gel electrophoresis in combination with cell assays and immunoassays for detection of enterotoxins. In faecal samples...... from animals receiving vegetative cells, only few B. cereus cells were detected. Spores survived the gastric barrier well, and were in some cases detected up to 2 weeks after ingestion. Selective growing revealed no major changes in the intestinal flora during passage of B. cereus. However, denaturing...

  12. The dynamic role of autophagy and MAPK signaling in determining cell fate under cisplatin stress in osteosarcoma cells.

    Directory of Open Access Journals (Sweden)

    Sudeshna Mukherjee

    Full Text Available Osteosarcoma (OS is an aggressive bone malignancy commonly observed in children and adolescents. Sub-optimal therapy for years has irretrievably compromised the chances of OS patient survival; also, lack of extensive research on this rare disease has hindered therapeutic development. Cisplatin, a common anti-tumor drug, is currently an integral part of treatment regime for OS along with methotrexate and doxorubicin. However, toxicity issues associated with combination module impede OS therapy. Also, despite the proven benefits of cisplatin, acquisition of resistance remains a concern with cisplatin-based therapy. This prompted us to investigate the molecular effects of cisplatin exposure and changes associated with acquired resistance in OS cells. Cisplatin shock was found to activate MAPK signaling and autophagy in OS cells. An activation of JNK and autophagy acted as pro-survival strategy, while ERK1/2 triggered apoptotic signals upon cisplatin stress. A crosstalk between JNK and autophagy was observed. Maximal sensitivity to cisplatin was obtained with simultaneous inhibition of both autophagy and JNK pathway. Cisplatin resistant cells were further developed by repetitive drug exposure followed by clonal selection. The resistant cells showed an altered signaling circuitry upon cisplatin exposure. Our results provide valuable cues to possible molecular alterations that can be considered for development of improved therapeutic strategy against osteosarcoma.

  13. Innate signals overcome acquired TCR signaling pathway regulation and govern the fate of human CD161(hi) CD8α⁺ semi-invariant T cells.

    Science.gov (United States)

    Turtle, Cameron J; Delrow, Jeff; Joslyn, Rochelle C; Swanson, Hillary M; Basom, Ryan; Tabellini, Laura; Delaney, Colleen; Heimfeld, Shelly; Hansen, John A; Riddell, Stanley R

    2011-09-08

    Type 17 programmed CD161(hi)CD8α(+) T cells contribute to mucosal immunity to bacteria and yeast. In early life, microbial colonization induces proliferation of CD161(hi) cells that is dependent on their expression of a semi-invariant Vα7.2(+) TCR. Although prevalent in adults, CD161(hi)CD8α(+) cells exhibit weak proliferative and cytokine responses to TCR ligation. The mechanisms responsible for the dichotomous response of neonatal and adult CD161(hi) cells, and the signals that enable their effector function, have not been established. We describe acquired regulation of TCR signaling in adult memory CD161(hi)CD8α(+) T cells that is absent in cord CD161(hi) cells and adult CD161(lo) cells. Regulated TCR signaling in CD161(hi) cells was due to profound alterations in TCR signaling pathway gene expression and could be overcome by costimulation through CD28 or innate cytokine receptors, which dictated the fate of their progeny. Costimulation with IL-1β during TCR ligation markedly increased proinflammatory IL-17 production, while IL-12-induced Tc1-like function and restored the response to TCR ligation without costimulation. CD161(hi) cells from umbilical cord blood and granulocyte colony stimulating factor-mobilized leukaphereses differed in frequency and function, suggesting future evaluation of the contribution of CD161(hi) cells in hematopoietic stem cell grafts to transplant outcomes is warranted.

  14. Self-Organization of Genome Expression from Embryo to Terminal Cell Fate: Single-Cell Statistical Mechanics of Biological Regulation

    Directory of Open Access Journals (Sweden)

    Alessandro Giuliani

    2017-12-01

    Full Text Available A statistical mechanical mean-field approach to the temporal development of biological regulation provides a phenomenological, but basic description of the dynamical behavior of genome expression in terms of autonomous self-organization with a critical transition (Self-Organized Criticality: SOC. This approach reveals the basis of self-regulation/organization of genome expression, where the extreme complexity of living matter precludes any strict mechanistic approach. The self-organization in SOC involves two critical behaviors: scaling-divergent behavior (genome avalanche and sandpile-type critical behavior. Genome avalanche patterns—competition between order (scaling and disorder (divergence reflect the opposite sequence of events characterizing the self-organization process in embryo development and helper T17 terminal cell differentiation, respectively. On the other hand, the temporal development of sandpile-type criticality (the degree of SOC control in mouse embryo suggests the existence of an SOC control landscape with a critical transition state (i.e., the erasure of zygote-state criticality. This indicates that a phase transition of the mouse genome before and after reprogramming (immediately after the late 2-cell state occurs through a dynamical change in a control parameter. This result provides a quantitative open-thermodynamic appreciation of the still largely qualitative notion of the epigenetic landscape. Our results suggest: (i the existence of coherent waves of condensation/de-condensation in chromatin, which are transmitted across regions of different gene-expression levels along the genome; and (ii essentially the same critical dynamics we observed for cell-differentiation processes exist in overall RNA expression during embryo development, which is particularly relevant because it gives further proof of SOC control of overall expression as a universal feature.

  15. Hippocampal cell fate regulation by chronic cocaine during periods of adolescent vulnerability: Consequences of cocaine exposure during adolescence on behavioral despair in adulthood.

    Science.gov (United States)

    García-Cabrerizo, R; Keller, B; García-Fuster, M J

    2015-09-24

    Given that adolescence represents a critical moment for shaping adult behavior and may predispose to disease vulnerability later in life, the aim of this study was to find a vulnerable period during adolescence in which hippocampal cell fate regulation was altered by cocaine exposure, and to evaluate the long-term consequences of a cocaine experience during adolescence in affecting hippocampal plasticity and behavioral despair in adulthood. Study I: Male rats were treated with cocaine (15mg/kg, i.p.) or saline for 7 consecutive days during adolescence (early post-natal day (PND) 33-39, mid PND 40-46, late PND 47-53). Hippocampal plasticity (i.e., cell fate regulation, cell genesis) was evaluated 24h after the last treatment dose during the course of adolescence (PND 40, PND 47, PND 54). Study II: The consequences of cocaine exposure during adolescence (PND 33-39 or PND 33-46; 7 or 14days) were measured in adulthood at the behavioral (i.e., forced swim test, PND 62-63) and molecular (hippocampal cell markers, PND 64) levels. Chronic cocaine during early adolescence dysregulated FADD forms only in the hippocampus (HC), as compared to other brain regions, and during mid adolescence, impaired cell proliferation (Ki-67) and increased PARP-1 cleavage (a cell death maker) in the HC. Interestingly, chronic cocaine exposure during adolescence did not alter the time adult rats spent immobile in the forced swim test. These results suggest that this paradigm of chronic cocaine administration during adolescence did not contribute to the later manifestation of behavioral despair (i.e., one pro-depressive symptom) as measured by the forced swim test in adulthood. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  16. Mitochondrial Networking in T Cell Memory.

    Science.gov (United States)

    Liesa, Marc; Shirihai, Orian S

    2016-06-30

    T-lymphocytes show large changes in ATP demand and nutrient utilization, imposed by their different roles as T memory and T effector cells. Therefore, T cell remodeling represents a bioenergetic challenge to mitochondria. New work from Buck et al. links changes in mitochondrial shape to T cell fate choice. Copyright © 2016. Published by Elsevier Inc.

  17. Perception of young adults with sickle cell disease or sickle cell trait about participation in the CHOICES randomized controlled trial.

    Science.gov (United States)

    Hershberger, Patricia E; Gallo, Agatha M; Molokie, Robert; Thompson, Alexis A; Suarez, Marie L; Yao, Yingwei; Wilkie, Diana J

    2016-06-01

    To gain an in-depth understanding of the perceptions of young adults with sickle cell disease and sickle cell trait about parenthood and participating in the CHOICES randomized controlled trial that used computer-based, educational programmes. In the USA, there is insufficient education to assure that all young adults with sickle cell disease or sickle cell trait understand genetic inheritance risks and reproductive options to make informed reproductive decisions. To address this educational need, we developed a computer-based, multimedia program (CHOICES) and reformatted usual care into a computer-based (e-Book) program. We then conducted a two-year randomized controlled trial that included a qualitative component that would deepen understanding of young adults' perceptions of parenthood and use of computer-based, educational programmes. A qualitative descriptive approach completed after a randomized controlled trial. Sixty-eight men and women of childbearing age participated in semi-structured interviews at the completion of the randomized controlled trial from 2012-2013. Thematic content analysis guided the qualitative description. Three main themes were identified: (1) increasing knowledge and new ways of thinking and behaving; (2) rethinking parenting plans; and (3) appraising the program design and delivery. Most participants reported increased knowledge and rethinking of their parenting plans and were supportive of computer-based learning. Some participants expressed difficulty in determining individual transmission risks. Participants perceived the computer programs as beneficial to their learning. Future development of an Internet-based educational programme is warranted, with emphasis on providing tailored education or memory boosters about individual transmission risks. © 2015 John Wiley & Sons Ltd.

  18. Notch and presenilin regulate cellular expansion and cytokine secretion but cannot instruct Th1/Th2 fate acquisition.

    Directory of Open Access Journals (Sweden)

    Chin-Tong Ong

    2008-07-01

    Full Text Available Recent reports suggested that Delta1, 4 and Jagged1, 2 possessed the ability to instruct CD4(+ T cell into selection of Th1 or Th2 fates, respectively, although the underlying mechanism endowing the cleaved Notch receptor with memory of ligand involved in its activation remains elusive. To examine this, we prepared artificial antigen-presenting cells expressing either DLL1 or Jag1. Although both ligands were efficient in inducing Notch2 cleavage and activation in CD4(+ T or reporter cells, the presence of Lunatic Fringe in CD4(+ T cells inhibited Jag1 activation of Notch1 receptor. Neither ligand could induce Th1 or Th2 fate choice independently of cytokines or redirect cytokine-driven Th1 or Th2 development. Instead, we find that Notch ligands only augment cytokine production during T cell differentiation in the presence of polarizing IL-12 and IL-4. Moreover, the differentiation choices of naïve CD4(+ T cells lacking gamma-secretase, RBP-J, or both in response to polarizing cytokines revealed that neither presenilin proteins nor RBP-J were required for cytokine-induced Th1/Th2 fate selection. However, presenilins facilitate cellular proliferation and cytokine secretion in an RBP-J (and thus, Notch independent manner. The controversies surrounding the role of Notch and presenilins in Th1/Th2 polarization may reflect their role as genetic modifiers of T-helper cells differentiation.

  19. Genome-wide ChIP-seq and RNA-seq analyses of Pou3f1 during mouse pluripotent stem cell neural fate commitment.

    Science.gov (United States)

    Song, Lu; Sun, Na; Peng, Guangdun; Chen, Jun; Han, Jing-Dong Jackie; Jing, Naihe

    2015-09-01

    Appropriate neural initiation of the pluripotent stem cells in the early embryos is critical for the development of the central nervous system. This process is regulated by the coordination of extrinsic signals and intrinsic programs. However, how the coordination is achieved to ensure proper neural fate commitment is largely unknown. Here, taking advantage of genome-wide ChIP-sequencing (ChIP-seq) and RNA-sequencing (RNA-seq) analyses, we demonstrate that the transcriptional factor Pou3f1 is an upstream activator of neural-promoting genes, and it is able to repress neural-inhibitory signals as well. Further studies revealed that Pou3f1 could directly bind neural lineage genes like Sox2 and downstream targets of neural inhibition signaling such as BMP and Wnt. Our results thus identify Pou3f1 as a critical dual-regulator of the intrinsic transcription factors and the extrinsic cellular signals during neural fate commitment. Data were deposited in Gene Expression Omnibus (GEO) datasets under reference number GSE69865.

  20. Images of cell trees, cell lines, and cell fates: the legacy of Ernst Haeckel and August Weismann in stem cell research.

    Science.gov (United States)

    Dröscher, Ariane

    2014-01-01

    Stem cells did not become a proper research object until the 1960 s. Yet the term and the basic mind-set--namely the conception of single undifferentiated cells, be they embryonic or adult, as the basic units responsible for a directed process of development, differentiation and increasing specialisation--were already in place at the end of the nineteenth century and then transmitted on a non-linear path in the form of tropes and diagrams. Ernst Haeckel and August Weismann played a special role in this story. The first coined the term Stammzelle (stem cell), the second was the author of the first cellular stem-tree diagram. Even today, I shall argue, the understanding of stem cells, especially the popular perception, is to a large extent a Haeckelian-Weismannian one. After having demonstrated this, by analysing the terminology, in this essay I will focus on the use of cytogenetic tree diagrams between 1892 and 1925 and on the tacit understanding of stem cells that they transmit.

  1. Comprehensive Identification of Long Non-coding RNAs in Purified Cell Types from the Brain Reveals Functional LncRNA in OPC Fate Determination.

    Directory of Open Access Journals (Sweden)

    Xiaomin Dong

    2015-12-01

    Full Text Available Long non-coding RNAs (lncRNAs (> 200 bp play crucial roles in transcriptional regulation during numerous biological processes. However, it is challenging to comprehensively identify lncRNAs, because they are often expressed at low levels and with more cell-type specificity than are protein-coding genes. In the present study, we performed ab initio transcriptome reconstruction using eight purified cell populations from mouse cortex and detected more than 5000 lncRNAs. Predicting the functions of lncRNAs using cell-type specific data revealed their potential functional roles in Central Nervous System (CNS development. We performed motif searches in ENCODE DNase I digital footprint data and Mouse ENCODE promoters to infer transcription factor (TF occupancy. By integrating TF binding and cell-type specific transcriptomic data, we constructed a novel framework that is useful for systematically identifying lncRNAs that are potentially essential for brain cell fate determination. Based on this integrative analysis, we identified lncRNAs that are regulated during Oligodendrocyte Precursor Cell (OPC differentiation from Neural Stem Cells (NSCs and that are likely to be involved in oligodendrogenesis. The top candidate, lnc-OPC, shows highly specific expression in OPCs and remarkable sequence conservation among placental mammals. Interestingly, lnc-OPC is significantly up-regulated in glial progenitors from experimental autoimmune encephalomyelitis (EAE mouse models compared to wild-type mice. OLIG2-binding sites in the upstream regulatory region of lnc-OPC were identified by ChIP (chromatin immunoprecipitation-Sequencing and validated by luciferase assays. Loss-of-function experiments confirmed that lnc-OPC plays a functional role in OPC genesis. Overall, our results substantiated the role of lncRNA in OPC fate determination and provided an unprecedented data source for future functional investigations in CNS cell types. We present our datasets and

  2. Dmrt5, a Novel Neurogenic Factor, Reciprocally Regulates Lhx2 to Control the Neuron-Glia Cell-Fate Switch in the Developing Hippocampus.

    Science.gov (United States)

    Muralidharan, Bhavana; Keruzore, Marc; Pradhan, Saurabh J; Roy, Basabdatta; Shetty, Ashwin S; Kinare, Veena; D'Souza, Leora; Maheshwari, Upasana; Karmodiya, Krishanpal; Suresh, Agasthya; Galande, Sanjeev; Bellefroid, Eric J; Tole, Shubha

    2017-11-15

    Regulation of the neuron-glia cell-fate switch is a critical step in the development of the CNS. Previously, we demonstrated that Lhx2 is a necessary and sufficient regulator of this process in the mouse hippocampal primordium, such that Lhx2 overexpression promotes neurogenesis and suppresses gliogenesis, whereas loss of Lhx2 has the opposite effect. We tested a series of transcription factors for their ability to mimic Lhx2 overexpression and suppress baseline gliogenesis, and also to compensate for loss of Lhx2 and suppress the resulting enhanced level of gliogenesis in the hippocampus. Here, we demonstrate a novel function of Dmrt5/Dmrta2 as a neurogenic factor in the developing hippocampus. We show that Dmrt5, as well as known neurogenic factors Neurog2 and Pax6, can each not only mimic Lhx2 overexpression, but also can compensate for loss of Lhx2 to different extents. We further uncover a reciprocal regulatory relationship between Dmrt5 and Lhx2, such that each can compensate for loss of the other. Dmrt5 and Lhx2 also have opposing regulatory control on Pax6 and Neurog2, indicating a complex bidirectionally regulated network that controls the neuron-glia cell-fate switch.SIGNIFICANCE STATEMENT We identify Dmrt5 as a novel regulator of the neuron-glia cell-fate switch in the developing hippocampus. We demonstrate Dmrt5 to be neurogenic, and reciprocally regulated by Lhx2: loss of either factor promotes gliogenesis; overexpression of either factor suppresses gliogenesis and promotes neurogenesis; each can substitute for loss of the other. Furthermore, each factor has opposing effects on established neurogenic genes Neurog2 and Pax6 Dmrt5 is known to suppress their expression, and we show that Lhx2 is required to maintain it. Our study reveals a complex regulatory network with bidirectional control of a fundamental feature of CNS development, the control of the production of neurons versus astroglia in the developing hippocampus.Finally, we confirm that Lhx2

  3. Jxc1/Sobp, encoding a nuclear zinc finger protein, is critical for cochlear growth, cell fate, and patterning of the organ of corti.

    Science.gov (United States)

    Chen, Zheng; Montcouquiol, Mireille; Calderon, Rene; Jenkins, Nancy A; Copeland, Neal G; Kelley, Matthew W; Noben-Trauth, Konrad

    2008-06-25

    The mouse cochlea emerges from the ventral pole of the otocyst to form a one and three-quarter coil. Little is known about the factors that control the growth of the cochlea. Jackson circler (jc) is a recessive mutation causing deafness resulting from a growth arrest of the cochlea duct at day 13.5 of embryonic development. Here, we identify the vertebrate homolog of the Drosophila Sobp (sine oculis-binding protein) gene (named Jxc1) in the jc locus. Jxc1 encodes a nuclear protein that has two FCS-type zinc finger domains (PS51024) and bears nuclear localization signals and highly conserved sequence motifs. Transiently expressed wild-type protein is targeted to the nucleus, but mutant isoforms were mislocalized in the cytoplasm. In jc mutants, the cellular patterning of the organ of Corti is severely disrupted, exhibiting supernumerary hair cells at the apex, showing mirror-image duplications of tunnel of Corti and inner hair cells, and expressing ectopic vestibular-like hair cells within Kölliker's organ. Jxc1 mRNA was detected in inner ear sensory hair cells, supporting cells, and the acoustic ganglia. Expression was also found in the developing retina, olfactory epithelium, trigeminal ganglion, and hair follicles. Collectively, our data support a role for Jxc1 in controlling a critical step in cochlear growth, cell fate, and patterning of the organ of Corti.

  4. Reproductive Health CHOICES for Young Adults with Sickle Cell Disease or Trait: Randomized Controlled Trial Outcomes over Two Years.

    Science.gov (United States)

    Gallo, Agatha M; Wilkie, Diana J; Yao, Yingwei; Molokie, Robert E; Stahl, Christiane; Hershberger, Patricia E; Zhao, Zhongsheng; Suarez, Marie L; Johnson, Bonnye; Angulo, Rigoberto; Carrasco, Jesus; Angulo, Veronica; Thompson, Alexis A

    2016-04-01

    Interventions to assist reproductive health decision-making in populations affected by sickle cell disease (SCD) or trait (SCT) lack proven efficacy over time. Our aim was to compare effects of CHOICES, a Web-based multimedia education program on implementing informed reproductive plans, and usual care education (e-Book) on reproductive knowledge, intention, and behavior over 24 months. We randomized 234 participants with SCD (n = 138) or SCT (n = 96) (age 18-35 years, 35 % male, 94 % African American) to CHOICES and e-Book groups. Participants completed a sickle cell-specific reproductive measure before and four times after the intervention (6, 12, 18 and 24 months). Compared to the e-Book group the CHOICES group had significantly more improvement in knowledge over time (p = .004) but not intention (p = .18) or behavior (p = .69). At baseline, 114 (48.7 %) participants reported having partners who would not put the couple at risk for their children inheriting SCD. Of the 116 (49.6 %) at-risk participants, a higher poroportion of those who were in the CHOICES group chose partners that reduced their risk by the last visit than the e-Book group (p = .04). Study findings provide important insights for designing a national trial of the CHOICES intervention focusing on subjects whose partner status puts them at risk for having a child with SCD.

  5. The bantam microRNA is associated with drosophila fragile X mental retardation protein and regulates the fate of germline stem cells.

    Directory of Open Access Journals (Sweden)

    Yingyue Yang

    2009-04-01

    Full Text Available Fragile X syndrome, a common form of inherited mental retardation, is caused by the loss of fragile X mental retardation protein (FMRP. We have previously demonstrated that dFmr1, the Drosophila ortholog of the fragile X mental retardation 1 gene, plays a role in the proper maintenance of germline stem cells in Drosophila ovary; however, the molecular mechanism behind this remains elusive. In this study, we used an immunoprecipitation assay to reveal that specific microRNAs (miRNAs, particularly the bantam miRNA (bantam, are physically associated with dFmrp in ovary. We show that, like dFmr1, bantam is not only required for repressing primordial germ cell differentiation, it also functions as an extrinsic factor for germline stem cell maintenance. Furthermore, we find that bantam genetically interacts with dFmr1 to regulate the fate of germline stem cells. Collectively, our results support the notion that the FMRP-mediated translation pathway functions through specific miRNAs to control stem cell regulation.

  6. Genetic manipulation of individual somatic mammary cells in vivo reveals a master role of STAT5a in inducing alveolar fate commitment and lactogenesis even in the absence of ovarian hormones.

    Science.gov (United States)

    Dong, Jie; Tong, Tammy; Reynado, Amanda M; Rosen, Jeffrey M; Huang, Shixia; Li, Yi

    2010-10-15

    Assessing the molecular control of development and cell fate in individual cells in the intact mammary epithelium has not been possible to date. By exploiting an intraductal retrovirus (RCAS)-mediated gene delivery method to introduce a marker gene, we found that ductal epithelial cells are turned over with a half time of approximately 1month in adult virgin mice. However, following RCAS-mediated introduction of a constitutively activated STAT5a (caSTAT5a), caSTAT5a-activated ductal epithelial cells expand and replace other cells in the epithelium, eventually forming a mammary gland resembling that in a late pregnant mouse, suggesting that STAT5a activation alone is sufficient to mediate pregnancy-induced mammary cell expansion, alveolar cell fate commitment, and lactogenesis. Furthermore, such caSTAT5a-induced alveolar differentiation does not require ovarian functions, although caSTAT5a-induced cell proliferation is partly reduced in ovariectomized mice. In conclusion, in this first report of studying the developmental role of a gene in a few cells in a normally developed virgin mammary ductal tree, STAT5a activation causes alveolar fate commitment and lactogenesis, and with the help of ovarian hormones, drives alveolar expansion. Copyright © 2010 Elsevier Inc. All rights reserved.

  7. Choice of Cell Source in Cell-Based Therapies for Retinal Damage due to Age-Related Macular Degeneration: A Review

    Directory of Open Access Journals (Sweden)

    Sudhakar John

    2013-01-01

    Full Text Available Background. Age-related macular degeneration (AMD is a complex disorder that affects primarily the macula involving the retinal pigment epithelium (RPE but also to a certain extent the photoreceptor layer and the retinal neurons. Cell transplantation is a promising option for AMD and clinical trials are underway using different cell types. Methods. We hypothesize that instead of focusing on a particular cell source for concurrent regeneration of all the retinal layers and also to prevent exhaustive research on an array of cell sources for regeneration of each layer, the choice should depend on, precisely, which layer is damaged. Results. Thus, for a damage limited to the retinal pigment epithelial (RPE layer, the choice we suggest would be RPE cells. When the damage extends to rods and cones, the choice would be bone marrow stem cells and when retinal neurons are involved, relatively immature stem cell populations with an inherent capacity to yield neuronal lineage such as hematopoietic stem cells, embryonic stem cells, or induced pluripotent stem cells can be tried. Conclusion. This short review will prove to be a valuable guideline for those working on cell therapy for AMD to plan their future directions of research and therapy for this condition.

  8. A Positive Regulatory Loop between a Wnt-Regulated Non-coding RNA and ASCL2 Controls Intestinal Stem Cell Fate

    Directory of Open Access Journals (Sweden)

    Antonis Giakountis

    2016-06-01

    Full Text Available The canonical Wnt pathway plays a central role in stem cell maintenance, differentiation, and proliferation in the intestinal epithelium. Constitutive, aberrant activity of the TCF4/β-catenin transcriptional complex is the primary transforming factor in colorectal cancer. We identify a nuclear long non-coding RNA, termed WiNTRLINC1, as a direct target of TCF4/β-catenin in colorectal cancer cells. WiNTRLINC1 positively regulates the expression of its genomic neighbor ASCL2, a transcription factor that controls intestinal stem cell fate. WiNTRLINC1 interacts with TCF4/β-catenin to mediate the juxtaposition of its promoter with the regulatory regions of ASCL2. ASCL2, in turn, regulates WiNTRLINC1 transcriptionally, closing a feedforward regulatory loop that controls stem cell-related gene expression. This regulatory circuitry is highly amplified in colorectal cancer and correlates with increased metastatic potential and decreased patient survival. Our results uncover the interplay between non-coding RNA-mediated regulation and Wnt signaling and point to the diagnostic and therapeutic potential of WiNTRLINC1.

  9. Migration-driven aggregate behaviors of human mesenchymal stem cells on a dendrimer-immobilized surface direct differentiation toward a cardiomyogenic fate commitment.

    Science.gov (United States)

    Ogawa, Yuuki; Kim, Mee-Hae; Kino-Oka, Masahiro

    2016-11-01

    Dynamic behaviors of cell aggregates on a dendrimer surface were investigated to drive the directed differentiation of human mesenchymal stem cells (hMSCs) toward a cardiomyogenic lineage. Cell aggregates on the polyamidoamine dendrimer surface with fifth-generation (G5) of dendron structure showed dynamic changes in morphology associated with repetitive stretching and contracting during migration. Spatial-temporal observations revealed cellular movement in single aggregates by their morphological change through stretching and contracting on the G5 surface, suggesting that the dynamic behavior of aggregate causes mixing of cells. However, aggregates without cell-substrate adhesions on the low-binding culture surface sustained their spherical morphology without cellular movement within a single aggregate. Furthermore, β-catenin was observed at nuclei in aggregates on the G5 surface, and expression of the cardiomyocyte marker cardiac Troponin T (cTnT) was detected. However, β-catenin localized to the nuclei only in the outer region of the aggregate on the low-binding culture surface, and cTnT expression was restricted at the exterior surface of the aggregates. These observations indicate that cell mixing within aggregates on the G5 surface induced the directed differentiation of hMSCs toward a cardiomyogenic lineage by nuclear translocation of β-catenin through dissociation of cell-cell adhesions. These results suggest that migration-driven aggregate behaviors on the dendrimer surface caused repeated morphological changes of aggregate through stretching and contracting, leading to the directed differentiation of hMSCs toward a cardiomyogenic fate commitment. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  10. Determination of mesenchymal stem cell fate by pigment epithelium-derived factor (PEDF) results in increased adiposity and reduced bone mineral content

    Science.gov (United States)

    Gattu, Arijeet K.; Swenson, E. Scott; Iwakiri, Yasuko; Samuel, Varman T.; Troiano, Nancy; Berry, Ryan; Church, Christopher D.; Rodeheffer, Matthew S.; Carpenter, Thomas O.; Chung, Chuhan

    2013-01-01

    Pigment epithelium-derived factor (PEDF), the protein product of the SERPINF1 gene, has been linked to distinct diseases involving adipose or bone tissue, the metabolic syndrome, and osteogenesis imperfecta (OI) type VI. Since mesenchymal stem cell (MSC) differentiation into adipocytes vs. osteoblasts can be regulated by specific factors, PEDF-directed dependency of murine and human MSCs was assessed. PEDF inhibited adipogenesis and promoted osteoblast differentiation of murine MSCs, osteoblast precursors, and human MSCs. Blockade of adipogenesis by PEDF suppressed peroxisome proliferator-activated receptor-γ (PPARγ), adiponectin, and other adipocyte markers by nearly 90% compared with control-treated cells (P50% compared with controls, illustrating its systemic role as a negative regulator of adipogenesis. Bones from KO mice demonstrated a reduction in mineral content recapitulating the OI type VI phenotype. These results demonstrate that the human diseases associated with PEDF reflect its ability to modulate MSC differentiation.—Gattu, A. K., Swenson, E. S., Iwakiri, Y., Samuel, V. T., Troiano, N., Berry, R., Church, C. D., Rodeheffer, M. S., Carpenter, T. O., Chung, C. Determination of mesenchymal stem cell fate by pigment epithelium-derived factor (PEDF) results in increased adiposity and reduced bone mineral content. PMID:23887690

  11. SERPINB2 is a novel TGFβ-responsive lineage fate determinant of human bone marrow stromal cells

    DEFF Research Database (Denmark)

    Elsafadi, Mona; Manikandan, Muthurangan; Atteya, Muhammad

    2017-01-01

    TGF-β1, a multifunctional regulator of cell growth and differentiation, is the most abundant bone matrix growth factor. During differentiation of human bone stromal cells (hBMSCs), which constitute bone marrow osteoblast (OS) and adipocyte (AD) progenitor cells, continuous TGF-β1 (10 ng/ml) treat...

  12. Fate of tenogenic differentiation potential of human bone marrow stromal cells by uniaxial stretching affected by stretch-activated calcium channel agonist gadolinium.

    Directory of Open Access Journals (Sweden)

    Hui Yin Nam

    Full Text Available The role for mechanical stimulation in the control of cell fate has been previously proposed, suggesting that there may be a role of mechanical conditioning in directing mesenchymal stromal cells (MSCs towards specific lineage for tissue engineering applications. Although previous studies have reported that calcium signalling is involved in regulating many cellular processes in many cell types, its role in managing cellular responses to tensile loading (mechanotransduction of MSCs has not been fully elucidated. In order to establish this, we disrupted calcium signalling by blocking stretch-activated calcium channel (SACC in human MSCs (hMSCs in vitro. Passaged-2 hMSCs were exposed to cyclic tensile loading (1 Hz + 8% for 6, 24, 48, and 72 hours in the presence of the SACC blocker, gadolinium. Analyses include image observations of immunochemistry and immunofluorescence staining from extracellular matrix (ECM production, and measuring related tenogenic and apoptosis gene marker expression. Uniaxial tensile loading increased the expression of tenogenic markers and ECM production. However, exposure to strain in the presence of 20 μM gadolinium reduced the induction of almost all tenogenic markers and ECM staining, suggesting that SACC acts as a mechanosensor in strain-induced hMSC tenogenic differentiation process. Although cell death was observed in prolonged stretching, it did not appear to be apoptosis mediated. In conclusion, the knowledge gained in this study by elucidating the role of calcium in MSC mechanotransduction processes, and that in prolonged stretching results in non-apoptosis mediated cell death may be potential useful for regenerative medicine applications.

  13. Tbx1 is required autonomously for cell survival and fate in the pharyngeal core mesoderm to form the muscles of mastication

    Science.gov (United States)

    Kong, Ping; Racedo, Silvia E.; Macchiarulo, Stephania; Hu, Zunju; Carpenter, Courtney; Guo, Tingwei; Wang, Tao; Zheng, Deyou; Morrow, Bernice E.

    2014-01-01

    Velo-cardio-facial/DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a congenital anomaly disorder characterized by craniofacial anomalies including velo-pharyngeal insufficiency, facial muscle hypotonia and feeding difficulties, in part due to hypoplasia of the branchiomeric muscles. Inactivation of both alleles of mouse Tbx1, encoding a T-box transcription factor, deleted on chromosome 22q11.2, results in reduction or loss of branchiomeric muscles. To identify downstream pathways, we performed gene profiling of microdissected pharyngeal arch one (PA1) from Tbx1+/+ and Tbx1−/− embryos at stages E9.5 (somites 20–25) and E10.5 (somites 30–35). Basic helix–loop–helix (bHLH) transcription factors were reduced, while secondary heart field genes were increased in expression early and were replaced by an increase in expression of cellular stress response genes later, suggesting a change in gene expression patterns or cell populations. Lineage tracing studies using Mesp1Cre and T-Cre drivers showed that core mesoderm cells within PA1 were present at E9.5 but were greatly reduced by E10.5 in Tbx1−/− embryos. Using Tbx1Cre knock-in mice, we found that cells are lost due to apoptosis, consistent with increase in expression of cellular stress response genes at E10.5. To determine whether Tbx1 is required autonomously in the core mesoderm, we used Mesp1Cre and T-Cre mesodermal drivers in combination with inactivate Tbx1 and found reduction or loss of branchiomeric muscles from PA1. These mechanistic studies inform us that Tbx1 is required upstream of key myogenic genes needed for core mesoderm cell survival and fate, between E9.5 and E10.5, resulting in formation of the branchiomeric muscles. PMID:24705356

  14. Live fate-mapping of joint-associated fibroblasts visualizes expansion of cell contributions during zebrafish fin regeneration.

    Science.gov (United States)

    Tornini, Valerie A; Thompson, John D; Allen, Raymond L; Poss, Kenneth D

    2017-08-15

    The blastema is a mass of progenitor cells responsible for regeneration of amputated salamander limbs and fish fins. Previous studies have indicated that resident cell sources producing the blastema contribute lineage-restricted progeny to regenerating tissue. However, these studies have labeled general cell types rather than granular cell subpopulations, and they do not explain the developmental transitions that must occur for distal structures to arise from cells with proximal identities in the appendage stump. Here, we find that regulatory sequences of tph1b, which encodes an enzyme that synthesizes serotonin, mark a subpopulation of fibroblast-like cells restricted to the joints of uninjured adult zebrafish fins. Amputation stimulates serotonin production in regenerating fin fibroblasts, yet targeted tph1b mutations abrogating this response do not disrupt fin regeneration. In uninjured animals, tph1b-expressing cells contribute fibroblast progeny that remain restricted to joints throughout life. By contrast, upon amputation, tph1b+ joint cells give rise to fibroblasts that distribute across the entire lengths of regenerating fin rays. Our experiments visualize and quantify how incorporation into an appendage blastema broadens the progeny contributions of a cellular subpopulation that normally has proximodistal restrictions. © 2017. Published by The Company of Biologists Ltd.

  15. The interplay of the Notch signaling in hepatic stellate cells and macrophages determines the fate of liver fibrogenesis

    NARCIS (Netherlands)

    Bansal, Ruchi; Van Baarlen, Joop; Storm, G; Prakash, Jai

    2015-01-01

    Hepatic stellate cells (HSCs) known as master producers and macrophages as master regulators, are the key cell types that strongly contribute to the progression of liver fibrosis. Since Notch signaling regulates multiple cellular processes, we aimed to study the role of Notch signaling in HSCs

  16. Outdoor fate and environmental impact of polymer solar cells through leaching and emission to rainwater and soil

    DEFF Research Database (Denmark)

    Espinosa Martinez, Nieves; Zimmermann, Yannick-Serge; Benatto, Gisele Alves dos Reis

    2016-01-01

    and zinc to the environment through precipitated water for damaged solar cells, and also observed failure and emission from an initially undamaged device in an experiment that endured for 6 months. In the case of the damaged cells, we found that the drinking water limits for Ag were only exceeded on a few...

  17. Recent advances in phytoplasma research: from genetic diversity and genome evolution to pathogenic redirection of plant stem cell fate

    Science.gov (United States)

    Parasitizing phloem sieve cells and being transmitted by insects, phytoplasmas are a unique group of cell wall-less bacteria responsible for numerous plant diseases worldwide. Due to difficulties in establishing axenic culture of phytoplasmas, phenotypic characters suitable for conventional microbia...

  18. Acclimative changes in root epidermal cell fate in response to Fe and P deficiency: a specific role for auxin?

    Science.gov (United States)

    Schikora, A; Schmidt, W

    2001-01-01

    Root hair formation and the development of transfer cells in the rhizodermis was investigated in various existing auxin-related mutants of Arabidopsis thaliana and in the tomato mutant diageotropica. Wild-type Arabidopsis plants showed increased formation of root hairs when the seedlings were cultivated in Fe- or P-free medium. These extranumerary hairs were located in normal positions and in positions normally occupied by nonhair cells, e.g., over periclinal walls of underlying cortical cells. Defects in auxin transport or reduced auxin sensitivity inhibited the formation of root hairs in response to Fe deficiency completely but did only partly affect initiation and elongation of hairs in P-deficient roots. Application of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid or the auxin analog 2,4-dichlorophenoxyacetic acid did not rescue the phenotype of the auxin-resistant axr2 mutant under control and Fe-deficient conditions, indicating that functional AXR2 product is required for translating the Fe deficiency signal into the formation of extra hairs. The development of extra hairs in axr2 roots under P-replete conditions was not affected by auxin antagonists, suggesting that this process is independent of auxin signaling. In roots of tomato, growth under Fe-deficient conditions induced the formation of transfer cells in the root epidermis. Transfer cell frequency was enhanced by application of 2,4-dichlorophenoxyacetic acid but was not inhibited by the auxin transport inhibitor N-1-naphthylphthalamic acid. In the diageotropica mutant, which displays reduced sensitivity to auxin, transfer cells appeared to develop in both Fe-sufficient and Fe-deficient roots. Similar to the wild type, no reduction in transfer cell frequency was observed after application of the above auxin transport inhibitor. These data suggest that auxin has no primary function in inducing transfer cell development; the formation of transfer cells, however, appears to be affected by

  19. Differentiation of pluripotent stem cells into striatal projection neurons: a pure MSN fate may not be sufficient

    Directory of Open Access Journals (Sweden)

    Amy eReddington

    2014-12-01

    Full Text Available Huntington’s disease (HD is an autosomal dominant inherited disorder leading to the loss of DARPP-32 medium spiny projection neurons (‘MSNs’ in the striatum. The relative specificity of cell loss early in HD has made cell replacement by neural transplantation an attractive therapeutic possibility. Transplantation of human fetal striatal precursors has shown ‘proof-of-principle’ in clinical trials; however, the practical and ethical difficulty associated with sourcing fetal tissue has stimulated the need to identify alternative sources of donor cells that are more readily available and suitable for standardisation. The first generation of protocols to generate DARPP-32 positive MSN-like neurons from pluripotent stem cells are now available and have been successfully grafted in animal models of HD. However, whether these grafts can provide stable functional recovery to the level that can regularly be achieved with primary fetal striatal grafts remains to be demonstrated. Of particular concern, primary fetal striatal grafts are not homogeneous; they contain not only the MSN subpopulation of striatal projection neurons but also include diverse neuronal and glia cell types of the mature striatum that certainly contribute to normal striatal function. By contrast, present protocols for pluripotent stem cell differentiation just target specifying neurons of an MSN lineage, and evidence for functional integration of stem-cell derived grafts is correspondingly limited. Indeed, consideration of the features of full striatal reconstruction that is achieved with primary fetal striatal grafts suggests that effective stem cell-based therapy in HD will require that graft protocols be developed to allow inclusion of multiple striatal cell types, including interneurons and striatal glia. A rational solution to this technical challenge requires that we re-address the underlying question – what constitutes a functional striatal graft?

  20. Divalent metal transporter 1 regulates iron-mediated ROS and pancreatic ß cell fate in response to cytokines

    DEFF Research Database (Denmark)

    Hansen, Jakob Bondo; Tonnesen, Morten Fog; Madsen, Andreas Nygaard

    2012-01-01

    Reactive oxygen species (ROS) contribute to target-cell damage in inflammatory and iron-overload diseases. Little is known about iron transport regulation during inflammatory attack. Through a combination of in vitro and in vivo studies, we show that the proinflammatory cytokine IL-1ß induces...... divalent metal transporter 1 (DMT1) expression correlating with increased ß cell iron content and ROS production. Iron chelation and siRNA and genetic knockdown of DMT1 expression reduce cytokine-induced ROS formation and cell death. Glucose-stimulated insulin secretion in the absence of cytokines in Dmt1...

  1. Cell and Tissue Organization in the Circulatory and Ventilatory Systems Volume 1 Signaling in Cell Organization, Fate, and Activity, Part A Cell Structure and Environment

    CERN Document Server

    Thiriet, Marc

    2011-01-01

    The volumes in this authoritative series present a multidisciplinary approach to modeling and simulation of flows in the cardiovascular and ventilatory systems, especially multiscale modeling and coupled simulations. The cardiovascular and respiratory systems are tightly coupled, as their primary function is to supply oxygen to and remove carbon dioxide from the body's cells. Because physiological conduits have deformable and reactive walls, macroscopic flow behavior and prediction must be coupled to nano- and microscopic events in a corrector scheme of regulated mechanisms. Therefore, investigation of flows of blood and air in physiological conduits requires an understanding of the biology, chemistry, and physics of these systems together with the mathematical tools to describe their functioning.  The present volume is devoted to cellular events that allow adaptation to environmental conditions, particularly mechanotransduction. It begins with cell organization and a survey of cell types in the vasculatur...

  2. What���s luck got to do with it? Single cells, multiple fates, and biological non-determinism

    OpenAIRE

    Symmons, Orsolya; Raj, Arjun

    2016-01-01

    The field of single cell biology has morphed from a philosophical digression at its inception to a playground for quantitative biologists, to a major area of biomedical research. The last several years have witnessed an explosion of new technologies, allowing us to apply ever more of the modern molecular biology toolkit to single cells. Conceptual progress, however, has been comparatively slow. Here, we provide a framework for classifying both the origins of the differences between individual...

  3. A common Shox2-Nkx2-5 antagonistic mechanism primes the pacemaker cell fate in the pulmonary vein myocardium and sinoatrial node.

    Science.gov (United States)

    Ye, Wenduo; Wang, Jun; Song, Yingnan; Yu, Diankun; Sun, Cheng; Liu, Chao; Chen, Fading; Zhang, Yanding; Wang, Fen; Harvey, Richard P; Schrader, Laura; Martin, James F; Chen, YiPing

    2015-07-15

    In humans, atrial fibrillation is often triggered by ectopic pacemaking activity in the myocardium sleeves of the pulmonary vein (PV) and systemic venous return. The genetic programs that abnormally reinforce pacemaker properties at these sites and how this relates to normal sinoatrial node (SAN) development remain uncharacterized. It was noted previously that Nkx2-5, which is expressed in the PV myocardium and reinforces a chamber-like myocardial identity in the PV, is lacking in the SAN. Here we present evidence that in mice Shox2 antagonizes the transcriptional output of Nkx2-5 in the PV myocardium and in a functional Nkx2-5(+) domain within the SAN to determine cell fate. Shox2 deletion in the Nkx2-5(+) domain of the SAN caused sick sinus syndrome, associated with the loss of the pacemaker program. Explanted Shox2(+) cells from the embryonic PV myocardium exhibited pacemaker characteristics including node-like electrophysiological properties and the capability to pace surrounding Shox2(-) cells. Shox2 deletion led to Hcn4 ablation in the developing PV myocardium. Nkx2-5 hypomorphism rescued the requirement for Shox2 for the expression of genes essential for SAN development in Shox2 mutants. Similarly, the pacemaker-like phenotype induced in the PV myocardium in Nkx2-5 hypomorphs reverted back to a working myocardial phenotype when Shox2 was simultaneously deleted. A similar mechanism is also adopted in differentiated embryoid bodies. We found that Shox2 interacts with Nkx2-5 directly, and discovered a substantial genome-wide co-occupancy of Shox2, Nkx2-5 and Tbx5, further supporting a pivotal role for Shox2 in the core myogenic program orchestrating venous pole and pacemaker development. © 2015. Published by The Company of Biologists Ltd.

  4. A common Shox2–Nkx2-5 antagonistic mechanism primes the pacemaker cell fate in the pulmonary vein myocardium and sinoatrial node

    Science.gov (United States)

    Ye, Wenduo; Wang, Jun; Song, Yingnan; Yu, Diankun; Sun, Cheng; Liu, Chao; Chen, Fading; Zhang, Yanding; Wang, Fen; Harvey, Richard P.; Schrader, Laura; Martin, James F.; Chen, YiPing

    2015-01-01

    In humans, atrial fibrillation is often triggered by ectopic pacemaking activity in the myocardium sleeves of the pulmonary vein (PV) and systemic venous return. The genetic programs that abnormally reinforce pacemaker properties at these sites and how this relates to normal sinoatrial node (SAN) development remain uncharacterized. It was noted previously that Nkx2-5, which is expressed in the PV myocardium and reinforces a chamber-like myocardial identity in the PV, is lacking in the SAN. Here we present evidence that in mice Shox2 antagonizes the transcriptional output of Nkx2-5 in the PV myocardium and in a functional Nkx2-5+ domain within the SAN to determine cell fate. Shox2 deletion in the Nkx2-5+ domain of the SAN caused sick sinus syndrome, associated with the loss of the pacemaker program. Explanted Shox2+ cells from the embryonic PV myocardium exhibited pacemaker characteristics including node-like electrophysiological properties and the capability to pace surrounding Shox2− cells. Shox2 deletion led to Hcn4 ablation in the developing PV myocardium. Nkx2-5 hypomorphism rescued the requirement for Shox2 for the expression of genes essential for SAN development in Shox2 mutants. Similarly, the pacemaker-like phenotype induced in the PV myocardium in Nkx2-5 hypomorphs reverted back to a working myocardial phenotype when Shox2 was simultaneously deleted. A similar mechanism is also adopted in differentiated embryoid bodies. We found that Shox2 interacts with Nkx2-5 directly, and discovered a substantial genome-wide co-occupancy of Shox2, Nkx2-5 and Tbx5, further supporting a pivotal role for Shox2 in the core myogenic program orchestrating venous pole and pacemaker development. PMID:26138475

  5. Novel insights into the role of NF-κB p50 in astrocyte-mediated fate specification of adult neural progenitor cells

    Directory of Open Access Journals (Sweden)

    Valeria Bortolotto

    2017-01-01

    Full Text Available Within the CNS nuclear factor-kappa B (NF-κB transcription factors are involved in a wide range of functions both in homeostasis and in pathology. Over the years, our and other groups produced a vast array of information on the complex involvement of NF-κB proteins in different aspects of postnatal neurogenesis. In particular, several extracellular signals and membrane receptors have been identified as being able to affect neural progenitor cells (NPC and their progeny via NF-κB activation. A crucial role in the regulation of neuronal fate specification in adult hippocampal NPC is played by the NF-κB p50 subunit. NF-κB p50KO mice display a remarkable reduction in adult hippocampal neurogenesis which correlates with a selective defect in hippocampal-dependent short-term memory. Moreover absence of NF-κB p50 can profoundly affect the in vitro proneurogenic response of adult hippocampal NPC (ahNPC to several endogenous signals and drugs. Herein we briefly review the current knowledge on the pivotal role of NF-κB p50 in the regulation of adult hippocampal neurogenesis. In addition we discuss more recent data that further extend the relevance of NF-κB p50 to novel astroglia-derived signals which can influence neuronal specification of ahNPC and to astrocyte-NPC cross-talk.

  6. Iron stress-induced changes in root epidermal cell fate are regulated independently from physiological responses to low iron availability.

    Science.gov (United States)

    Schikora, A; Schmidt, W

    2001-04-01

    Iron-overaccumulating mutants were investigated with respect to changes in epidermal cell patterning and root reductase activity in response to iron starvation. In all mutants under investigation, ferric chelate reductase activity was up-regulated both in the presence and absence of iron in the growth medium. The induction of transfer cells in the rhizodermis appeared to be iron regulated in the pea (Pisum sativum L. cv Dippes Gelbe Viktoria and cv Sparkle) mutants bronze and degenerated leaflets, but not in roots of the tomato (Lycopersicon esculentum Mill. cv Bonner Beste) mutant chloronerva, suggesting that in chloronerva iron cannot be recognized by putative sensor proteins. Experiments with split-root plants supports the hypothesis that Fe(III) chelate reductase is regulated by a shoot-borne signal molecule, communicating the iron status of the shoot to the roots. In contrast, the formation of transfer cells was dependent on the local concentration of iron, implying that this shoot signal does not affect their formation. Different repression curves of the two responses imply that the induction of transfer cells occurs after the enhancement of electron transfer across the plasma membrane rather than being causally linked. Similar to transfer cells, the formation of extra root hairs in the Arabidopsis mutant man1 was regulated by the iron concentration of the growth medium and was unaffected by interorgan signaling.

  7. Transepithelial Transport of YWDHNNPQIR and Its Metabolic Fate with Cytoprotection against Oxidative Stress in Human Intestinal Caco-2 Cells.

    Science.gov (United States)

    Xu, Feiran; Wang, Lifeng; Ju, Xingrong; Zhang, Jing; Yin, Shi; Shi, Jiayi; He, Rong; Yuan, Qiang

    2017-03-15

    Studies on antioxidant peptides extracted from foodstuff sources have included not only experiments to elucidate their chemical characteristics but also to investigate their bioavailability and intracellular mechanisms. This study was designed to clarify the absorption and antioxidative activity of YWDHNNPQIR (named RAP), which is derived from rapeseed protein using a Caco-2 cell transwell model. Results showed that 0.8% RAP (C0 = 0.2 mM, t = 90 min) could maintain the original structure across the Caco-2 cell monolayers via the intracellular transcytosis pathway, and the apparent drug absorption rate (Papp) was (6.6 ± 1.24) × 10-7 cm/s. Three main fragments (WDHNNPQIR, DHNNPQIR, and YWDHNNPQ) and five modified peptides derived from RAP were found in both the apical and basolateral side of the Caco-2 cell transwell model. Among these new metabolites, WDHNNPQIR had the greatest antioxidative activity in Caco-2 cells apart from the DPPH assay. With a RAP concentration of 200 μM, there were significant differences in four antioxidative indicators (T-AOC, GSH-Px, SOD, and MDA) compared to the oxidative stress control (P Caco-2 cells, which was caused by AAPH-induced oxidative damage.

  8. Wnt/ß-catenin signalling and the dynamics of fate decisions in early mouse embryos and embryonic stem (ES) cells.

    Science.gov (United States)

    Muñoz-Descalzo, Silvia; Hadjantonakis, Anna-Katerina; Arias, Alfonso Martinez

    2015-12-01

    Wnt/ß-catenin signalling is a widespread cell signalling pathway with multiple roles during vertebrate development. In mouse embryonic stem (mES) cells, there is a dual role for ß-catenin: it promotes differentiation when activated as part of the Wnt/ß-catenin signalling pathway, and promotes stable pluripotency independently of signalling. Although mES cells resemble the preimplantation epiblast progenitors, the first requirement for Wnt/ß-catenin signalling during mouse development has been reported at implantation [1,2]. The relationship between ß-catenin and pluripotency and that of mES cells with epiblast progenitors suggests that ß-catenin might have a functional role during preimplantation development. Here we summarize the expression and function of Wnt/ß-catenin signalling elements during the early stages of mouse development and consider the reasons why the requirement in ES cells do not reflect the embryo. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  9. What’s luck got to do with it? Single cells, multiple fates, and biological non-determinism

    Science.gov (United States)

    Symmons, Orsolya; Raj, Arjun

    2016-01-01

    The field of single cell biology has morphed from a philosophical digression at its inception to a playground for quantitative biologists, to a major area of biomedical research. The last several years have witnessed an explosion of new technologies, allowing us to apply ever more of the modern molecular biology toolkit to single cells. Conceptual progress, however, has been comparatively slow. Here, we provide a framework for classifying both the origins of the differences between individual cells and the consequences of those differences. We discuss how the concept of “random” differences is context dependent, and propose that rigorous definitions of inputs and outputs may bring clarity to the discussion. We also categorize ways in which probabilistic behavior may influence cellular function, highlighting studies that point to exciting future directions in the field. PMID:27259209

  10. New Ways of Imaging Uptake and Intracellular Fate of Liposomal Drug Carrier Systems inside Individual Cells, Based on Raman Microscopy

    Science.gov (United States)

    Matthäus, Christian; Kale, Amit; Chernenko, Tatyana; Torchilin, Vladimir; Diem, Max

    2009-01-01

    Recent developments, combining Raman spectroscopy with optical microscopy, provide a new noninvasive technique to assess and image cellular processes. Of particular interest are the uptake mechanisms of various cytologically active compounds. In order to distinguish the species of interest from their cellular environment spectroscopically, compounds may be labeled with deuterium. Here, we apply Raman microspectroscopy to follow the uptake of liposomal drug carrier systems that have been introduced to deliver biologically active compounds to their site of action within human breast adenocarcinoma MCF-7 cells. The distribution patterns of liposomes and liposomes surface-modified with a cell-penetrating peptide (TAT-peptide, TATp) have been imaged over time. The spectroscopic information obtained provides a clear evidence for variable rates, as well as different efficiencies of liposome uptake depending on their surface properties. Depending on the experimental setup, the technique may be applied to fixed or living cell organisms. PMID:18197626

  11. An additional human chromosome 21 causes suppression of neural fate of pluripotent mouse embryonic stem cells in a teratoma model

    Directory of Open Access Journals (Sweden)

    Fisher Elizabeth

    2007-11-01

    Full Text Available Abstract Background Down syndrome (DS, caused by trisomy of human chromosome 21 (HSA21, is the most common genetic cause of mental retardation in humans. Among complex phenotypes, it displays a number of neural pathologies including smaller brain size, reduced numbers of neurons, reduced dendritic spine density and plasticity, and early Alzheimer-like neurodegeneration. Mouse models for DS show behavioural and cognitive defects, synaptic plasticity defects, and reduced hippocampal and cerebellar neuron numbers. Early postnatal development of both human and mouse-model DS shows the reduced capability of neuronal precursor cells to generate neurons. The exact molecular cause of this reduction, and the role played by increased dosage of individual HSA21 genes, remain unknown. Results We have subcutaneously injected mouse pluripotent ES cells containing a single freely segregating supernumerary human chromosome 21 (HSA21 into syngeneic mice, to generate transchromosomic teratomas. Transchromosomic cells and parental control cells were injected into opposite flanks of thirty mice in three independent experiments. Tumours were grown for 30 days, a time-span equivalent to combined intra-uterine, and early post-natal mouse development. When paired teratomas from the same animals were compared, transchromosomic tumours showed a three-fold lower percentage of neuroectodermal tissue, as well as significantly reduced mRNA levels for neuron specific (Tubb3 and glia specific (Gfap genes, relative to euploid controls. Two thirds of transchromosomic tumours also showed a lack of PCR amplification with multiple primers specific for HSA21, which were present in the ES cells at the point of injection, thus restricting a commonly retained trisomy to less than a third of HSA21 genes. Conclusion We demonstrate that a supernumerary chromosome 21 causes Inhibition of Neuroectodermal DIfferentiation (INDI of pluripotent ES cells. The data suggest that trisomy of less

  12. Anionic Sites, Fucose Residues and Class I Human Leukocyte Antigen Fate During Interaction of Toxoplasma gondii with Endothelial Cells

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    Stumbo Ana Carolina

    2002-01-01

    Full Text Available Toxoplasma gondii invades and proliferates in human umbilical vein endothelial cells where it resides in a parasitophorous vacuole. In order to analyze which components of the endothelial cell plasma membrane are internalized and become part of the parasitophorous vacuole membrane, the culture of endothelial cells was labeled with cationized ferritin or UEA I lectin or anti Class I human leukocytte antigen (HLA before or after infection with T. gondii. The results showed no cationized ferritin and UEA I lectin in any parasitophorous vacuole membrane, however, the Class I HLA molecule labeling was observed in some endocytic vacuoles containing parasite until 1 h of interaction with T. gondii. After 24 h parasite-host cell interaction, the labeling was absent on the vacuolar membrane, but presents only in small vesicles near parasitophorous vacuole. These results suggest the anionic site and fucose residues are excluded at the time of parasitophorous vacuole formation while Class I HLA molecules are present only on a minority of Toxoplasma-containig vacuoles.

  13. Role of cellular caspases, nuclear factor-kappa B and interferon regulatory factors in Bluetongue virus infection and cell fate

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    Roy Polly

    2010-12-01

    Full Text Available Abstract Background Bluetongue virus (BTV infection causes haemorrhagic disease in ruminants and induces cell death. The pathogenesis in animals and in cell culture has been linked to BTV-induced apoptosis. Results In this report, we investigated BTV-induced apoptosis in cell culture in depth and show that both extrinsic (caspase-8 activation and intrinsic (caspase-9 activation pathways play roles in BTV apoptosis. Further, by using chemical inhibitors and knock-out cell lines, we show that these pathways act independently of each other in BTV infected cells. In addition to activation of caspase-8, -9 and executioner caspase-3, we also identified that BTV infection causes the activation of caspase-7, which results in the cleavage of poly (ADP-ribose polymerase (PARP. BTV-induced cell death appears to be due to apoptosis rather than necrosis, as the HMBG-1 was not translocated from the nucleus. We also examined if NF-κB response is related to BTV-induced apoptosis as in reovirus. Our data suggests that NF-κB response is not linked to the induction of apoptosis. It is controlled by the degradation of only IκBα but not IκBβ, resulting in a rapid transient response during BTV infection. This was supported using an NF-κB dependent luciferase reporter gene assay, which demonstrated early response, that appeared to be suppressed by the late stage of BTV replication. Furthermore, virus titres were higher in the presence of NF-κB inhibitor (SN50, indicating that NF-κB has a role in initiating an antiviral environment. In addition, we show that BTV infection induces the translocation of interferon regulatory factors (IRF-3 and IRF-7 into the nucleus. The induction of IRF responses, when measured by IRF dependent luciferase reporter gene assay, revealed that the IRF responses, like NF-κB response, were also at early stage of infection and mirrored the timing of NF-κB induction. Conclusion BTV triggers a wide range of caspase activities resulting

  14. Options for tracking GFP-Labeled transplanted myoblasts using in vivo fluorescence imaging: implications for tracking stem cell fate.

    Science.gov (United States)

    Yang, Zhong; Wang, Yaming; Li, Yanan; Liu, Qiang; Zeng, Qing; Xu, Xiaoyin

    2014-06-12

    Green fluorescent protein (GFP) is a useful biomarker, widely used in biomedical research to track stem cells after transplantation and/or to assess therapeutic transgene expression. However, both GFP and therapeutic gene products themselves may be immunogenic to the recipient. The main aim of this study was to use animal models to evaluate potential impact of GFP on the cell engraftment and to optimize tracking strategies prior to transplantation. By using a fluorescent imaging (FLI) system, we investigated the dynamic cell behavior of GFP-transduced myoblasts in tibialis anterior (TA) muscles of immunocompetent mdx mice and immuno-compromised nude mice over a period of three months. The results suggested an apparent underlying host immunorejection in the mdx mice. Dystrophin immunostaining showed that the engraftment of wild type myoblasts was much more effective than that of the GFP-labeled counterparts in the mdx mice, further confirming an antigen role of GFP in this process. We tracked the GFP-transduced myoblasts in C57BL/6 mice and found GFP to be minimally immunogenic in these animals, as indicated by the GFP signal maintaining a much stronger level than that found in mdx and BALB/c mice at parallel time points. We also compared the in vivo cell behavior differences between myoblasts from virally GFP-transduced and GFP transgenic mice. The latter displayed much better engraftment, as determined both biomaging and histological observations. Our results not only demonstrated the immunogenicity of GFP in immunocompetent mice, but determined the optimized conditions for GFP-based in vivo stem cells tracking, that can potentially be extrapolated to human biomedical research.

  15. Strabismus-mediated primary archenteron invagination is uncoupled from Wnt/β-catenin-dependent endoderm cell fate specification in Nematostella vectensis (Anthozoa, Cnidaria: Implications for the evolution of gastrulation

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    Kumburegama Shalika

    2011-01-01

    Full Text Available Abstract Background Gastrulation is a uniquely metazoan character, and its genesis was arguably the key step that enabled the remarkable diversification within this clade. The process of gastrulation involves two tightly coupled events during embryogenesis of most metazoans. Morphogenesis produces a distinct internal epithelial layer in the embryo, and this epithelium becomes segregated as an endoderm/endomesodermal germ layer through the activation of a specific gene regulatory program. The developmental mechanisms that induced archenteron formation and led to the segregation of germ layers during metazoan evolution are unknown. But an increased understanding of development in early diverging taxa at the base of the metazoan tree may provide insights into the origins of these developmental mechanisms. Results In the anthozoan cnidarian Nematostella vectensis, initial archenteron formation begins with bottle cell-induced buckling of the blastula epithelium at the animal pole. Here, we show that bottle cell formation and initial gut invagination in Nematostella requires NvStrabismus (NvStbm, a maternally-expressed core component of the Wnt/Planar Cell Polarity (PCP pathway. The NvStbm protein is localized to the animal pole of the zygote, remains asymmetrically expressed through the cleavage stages, and becomes restricted to the apical side of invaginating bottle cells at the blastopore. Antisense morpholino-mediated NvStbm-knockdown blocks bottle cell formation and initial archenteron invagination, but it has no effect on Wnt/ß-catenin signaling-mediated endoderm cell fate specification. Conversely, selectively blocking Wnt/ß-catenin signaling inhibits endoderm cell fate specification but does not affect bottle cell formation and initial archenteron invagination. Conclusions Our results demonstrate that Wnt/PCP-mediated initial archenteron invagination can be uncoupled from Wnt/ß-catenin-mediated endoderm cell fate specification in

  16. Paper tests for occult blood in faeces and some observations on the fate of swallowed red cells

    Science.gov (United States)

    Huntsman, R. G.; Liddell, J.

    1961-01-01

    Paper tests for occult blood were assessed on faecal specimens from adults. An orthotolidine/sodium perborate and a modified orthotolidine/peroxide test were found to be reasonably satisfactory. The Hematest and Occultest tablets and a paper guaiac test were unsatisfactory. A large number of false positive results was obtained in children and infants. It is suggested that this might be due to meat derivatives reaching the faeces more easily in the young. Red cells labelled with either Cr51 or Fe59 were swallowed by human volunteers. Although between 45% and 73% of the red cell iron reappeared in the faeces, the peroxidase activity of the labelled material dropped six-fold on passage through the alimentary canal. PMID:13716912

  17. Uptake of auxotrophic cells of a heterocyst-forming cyanbacterium by tobacco protoplasts, and the fate of their associations

    Energy Technology Data Exchange (ETDEWEB)

    Meeks, J.C.; Malmberg, R.L.; Wolk, C.P.

    1978-01-01

    Auxotrophic cells of the filamentous cyanobacterium Anabaena variabilis Kutz. were introduced into protoplasts of Nicotiana tabacum L. in an attempt to engineer a nitrogen-fixing endosymbiosis. Conditions were established to maximize uptake of the cyanobacteria by use of polyethylene glycol. Culture of the novel association was not successful: tobacco protoplasts with Anabaena inside did not appear to divide. Most of the protoplasts expelled the cyanobacteria and simultaneously disintegrated. The reasons for the incompatibility are not known.

  18. Effect of Calcium-Infiltrated Hydroxyapatite Scaffolds on the Hematopoietic Fate of Human Umbilical Vein Endothelial Cells.

    Science.gov (United States)

    Zhang, Qinghao; Gerlach, Jörg C; Schmelzer, Eva; Nettleship, Ian

    2017-01-01

    Foamed hydroxyapatite offers a three-dimensional scaffold for the development of bone constructs, mimicking perfectly the in vivo bone structure. In vivo, calcium release at the surface is assumed to provide a locally increased gradient supporting the maintenance of the hematopoietic stem cells niche. We fabricated hydroxyapatite scaffolds with high surface calcium concentration by infiltration, and used human umbilical vein endothelial cells (HUVECs) as a model to study the effects on hematopoietic lineage direction. HUVECs are umbilical vein-derived and thus possess progenitor characteristics, with a prospective potential to give rise to hematopoietic lineages. HUVECs were cultured for long term on three-dimensional porous hydroxyapatite scaffolds, which were either infiltrated biphasic foams or untreated. Controls were cultured in two-dimensional dishes. The release of calcium into culture medium was determined, and cells were analyzed for typical hematopoietic and endothelial gene expressions, surface markers by flow cytometry, and hematopoietic potential using colony-forming unit assays. Our results indicate that the biphasic foams promoted a hematopoietic lineage direction of HUVECs, suggesting an improved in vivo-like scaffold for hematopoietic bone tissue engineering. © 2017 S. Karger AG, Basel.

  19. Retinoic Acid Receptors Control Spermatogonia Cell-Fate and Induce Expression of the SALL4A Transcription Factor.

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    Aurore Gely-Pernot

    2015-10-01

    Full Text Available All-trans retinoic acid (ATRA is instrumental to male germ cell differentiation, but its mechanism of action remains elusive. To address this question, we have analyzed the phenotypes of mice lacking, in spermatogonia, all rexinoid receptors (RXRA, RXRB and RXRG or all ATRA receptors (RARA, RARB and RARG. We demonstrate that the combined ablation of RXRA and RXRB in spermatogonia recapitulates the set of defects observed both upon ablation of RAR in spermatogonia. We also show that ATRA activates RAR and RXR bound to a conserved regulatory region to increase expression of the SALL4A transcription factor in spermatogonia. Our results reveal that this major pluripotency gene is a target of ATRA signaling and that RAR/RXR heterodimers are the functional units driving its expression in spermatogonia. They add to the mechanisms through which ATRA promote expression of the KIT tyrosine kinase receptor to trigger a critical step in spermatogonia differentiation. Importantly, they indicate also that meiosis eventually occurs in the absence of a RAR/RXR pathway within germ cells and suggest that instructing this process is either ATRA-independent or requires an ATRA signal originating from Sertoli cells.

  20. The influence of cytokinin-auxin cross-regulation on cell-fate determination in Arabidopsis thaliana root development.

    Science.gov (United States)

    Muraro, Daniele; Byrne, Helen; King, John; Voss, Ute; Kieber, Joseph; Bennett, Malcolm

    2011-08-21

    Root growth and development in Arabidopsis thaliana are sustained by a specialised zone termed the meristem, which contains a population of dividing and differentiating cells that are functionally analogous to a stem cell niche in animals. The hormones auxin and cytokinin control meristem size antagonistically. Local accumulation of auxin promotes cell division and the initiation of a lateral root primordium. By contrast, high cytokinin concentrations disrupt the regular pattern of divisions that characterises lateral root development, and promote differentiation. The way in which the hormones interact is controlled by a genetic regulatory network. In this paper, we propose a deterministic mathematical model to describe this network and present model simulations that reproduce the experimentally observed effects of cytokinin on the expression of auxin regulated genes. We show how auxin response genes and auxin efflux transporters may be affected by the presence of cytokinin. We also analyse and compare the responses of the hormones auxin and cytokinin to changes in their supply with the responses obtained by genetic mutations of SHY2, which encodes a protein that plays a key role in balancing cytokinin and auxin regulation of meristem size. We show that although shy2 mutations can qualitatively reproduce the effect of varying auxin and cytokinin supply on their response genes, some elements of the network respond differently to changes in hormonal supply and to genetic mutations, implying a different, general response of the network. We conclude that an analysis based on the ratio between these two hormones may be misleading and that a mathematical model can serve as a useful tool for stimulate further experimental work by predicting the response of the network to changes in hormone levels and to other genetic mutations. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Distinct and overlapping gene regulatory networks in BMP- and HDAC-controlled cell fate determination in the embryonic forebrain

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    Scholl Catharina

    2012-07-01

    Full Text Available Abstract Background Both bone morphogenetic proteins (BMPs and histone deacetylases (HDACs have previously been established to play a role in the development of the three major cell types of the central nervous system: neurons, astrocytes, and oligodendrocytes. We have previously established a connection between these two protein families, showing that HDACs suppress BMP-promoted astrogliogenesis in the embryonic striatum. Since HDACs act in the nucleus to effect changes in transcription, an unbiased analysis of their transcriptional targets could shed light on their downstream effects on BMP-signaling. Results Using neurospheres from the embryonic striatum as an in vitro system to analyze this phenomenon, we have performed microarray expression profiling on BMP2- and TSA-treated cultures, followed by validation of the findings with quantitative RT-PCR and protein analysis. In BMP-treated cultures we first observed an upregulation of genes involved in cell-cell communication and developmental processes such as members of BMP and canonical Wnt signaling pathways. In contrast, in TSA-treated cultures we first observed an upregulation of genes involved in chromatin modification and transcription. Interestingly, we could not record direct changes in the protein levels of canonical members of BMP2 signaling, but we did observe an upregulation of both the transcription factor STAT3 and its active isoform phospho-STAT3 at the protein level. Conclusions STAT3 and SMAD1/5/8 interact synergistically to promote astrogliogenesis, and thus we show for the first time that HDACs act to suppress BMP-promoted astrogliogenesis by suppression of the crucial partner STAT3.

  2. The SoxD transcription factors – Sox5, Sox6, and Sox13 – are key cell fate modulators

    OpenAIRE

    Lefebvre, Véronique

    2009-01-01

    Sox5, Sox6, and Sox13 constitute the group D of sex-determining region (Sry)-related transcription factors. They are highly conserved in the family-specific high-mobility-group (HMG) box DNA-binding domain and in a group-specific coiled-coil domain. The latter mediates SoxD protein dimerization and thereby preferential binding to pairs of DNA recognition sites. The SoxD genes have overlapping expression and cell-autonomously control discrete lineages. Sox5 and Sox6 redundantly enhance chondro...

  3. Metabolic switching and fuel choice during T-cell differentiation and memory development

    NARCIS (Netherlands)

    van der Windt, Gerritje J. W.; Pearce, Erika L.

    2012-01-01

    Clearance or control of pathogens or tumors usually requires T-cell-mediated immunity. As such, understanding the mechanisms that govern the function, maintenance, and persistence of T cells will likely lead to new treatments for controlling disease. During an immune response, T-cell development is

  4. Tbx1 is required autonomously for cell survival and fate in the pharyngeal core mesoderm to form the muscles of mastication.

    Science.gov (United States)

    Kong, Ping; Racedo, Silvia E; Macchiarulo, Stephania; Hu, Zunju; Carpenter, Courtney; Guo, Tingwei; Wang, Tao; Zheng, Deyou; Morrow, Bernice E

    2014-08-15

    Velo-cardio-facial/DiGeorge syndrome, also known as 22q11.2 deletion syndrome, is a congenital anomaly disorder characterized by craniofacial anomalies including velo-pharyngeal insufficiency, facial muscle hypotonia and feeding difficulties, in part due to hypoplasia of the branchiomeric muscles. Inactivation of both alleles of mouse Tbx1, encoding a T-box transcription factor, deleted on chromosome 22q11.2, results in reduction or loss of branchiomeric muscles. To identify downstream pathways, we performed gene profiling of microdissected pharyngeal arch one (PA1) from Tbx1(+/+) and Tbx1(-/-) embryos at stages E9.5 (somites 20-25) and E10.5 (somites 30-35). Basic helix-loop-helix (bHLH) transcription factors were reduced, while secondary heart field genes were increased in expression early and were replaced by an increase in expression of cellular stress response genes later, suggesting a change in gene expression patterns or cell populations. Lineage tracing studies using Mesp1(Cre) and T-Cre drivers showed that core mesoderm cells within PA1 were present at E9.5 but were greatly reduced by E10.5 in Tbx1(-/-) embryos. Using Tbx1(Cre) knock-in mice, we found that cells are lost due to apoptosis, consistent with increase in expression of cellular stress response genes at E10.5. To determine whether Tbx1 is required autonomously in the core mesoderm, we used Mesp1(Cre) and T-Cre mesodermal drivers in combination with inactivate Tbx1 and found reduction or loss of branchiomeric muscles from PA1. These mechanistic studies inform us that Tbx1 is required upstream of key myogenic genes needed for core mesoderm cell survival and fate, between E9.5 and E10.5, resulting in formation of the branchiomeric muscles. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Wnt signaling positively regulates endothelial cell fate specification in the Fli1a-positive progenitor population via Lef1.

    Science.gov (United States)

    Hübner, Kathleen; Grassme, Kathrin S; Rao, Jyoti; Wenke, Nina K; Zimmer, Cordula L; Korte, Laura; Mu Ller, Katja; Sumanas, Saulius; Greber, Boris; Herzog, Wiebke

    2017-10-01

    During vertebrate embryogenesis, vascular endothelial cells (ECs) and primitive erythrocytes become specified within close proximity in the posterior lateral plate mesoderm (LPM) from a common progenitor. However, the signaling cascades regulating the specification into either lineage remain largely elusive. Here, we analyze the contribution of β-catenin dependent Wnt signaling to EC and erythrocyte specification during zebrafish embryogenesis. We generated novel β-catenin dependent Wnt signaling reporters which, by using destabilized fluorophores (Venus-Pest, dGFP), specifically allow us to detect Wnt signaling responses in narrow time windows as well as in spatially restricted domains, defined by Cre recombinase expression (Tg(axin2 BAC :Venus-Pest) mu288 ; Tg(14TCF:loxP-STOP-loxP-dGFP) mu202 ). We therefore can detect β-catenin dependent Wnt signaling activity in a subset of the Fli1a-positive progenitor population. Additionally, we show that mesodermal Wnt3a-mediated signaling via the transcription factor Lef1 positively regulates EC specification (defined by kdrl expression) at the expense of primitive erythrocyte specification (defined by gata1 expression) in zebrafish embryos. Using mesoderm derived from human embryonic stem cells, we identified the same principle of Wnt signaling dependent EC specification in conjunction with auto-upregulation of LEF1. Our data indicate a novel role of β-catenin dependent Wnt signaling in regulating EC specification during vasculogenesis. Copyright © 2017. Published by Elsevier Inc.

  6. Conserved sequence-specific lincRNA-steroid receptor interactions drive transcriptional repression and direct cell fate

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, William H.; Pickard, Mark R.; de Vera, Ian Mitchelle S.; Kuiper, Emily G.; Mourtada-Maarabouni, Mirna; Conn, Graeme L.; Kojetin, Douglas J.; Williams, Gwyn T.; Ortlund, Eric A. [Emory-MED; (Keele); (Scripps)

    2014-12-23

    The majority of the eukaryotic genome is transcribed, generating a significant number of long intergenic noncoding RNAs (lincRNAs). Although lincRNAs represent the most poorly understood product of transcription, recent work has shown lincRNAs fulfill important cellular functions. In addition to low sequence conservation, poor understanding of structural mechanisms driving lincRNA biology hinders systematic prediction of their function. Here we report the molecular requirements for the recognition of steroid receptors (SRs) by the lincRNA growth arrest-specific 5 (Gas5), which regulates steroid-mediated transcriptional regulation, growth arrest and apoptosis. We identify the functional Gas5-SR interface and generate point mutations that ablate the SR-Gas5 lincRNA interaction, altering Gas5-driven apoptosis in cancer cell lines. Further, we find that the Gas5 SR-recognition sequence is conserved among haplorhines, with its evolutionary origin as a splice acceptor site. This study demonstrates that lincRNAs can recognize protein targets in a conserved, sequence-specific manner in order to affect critical cell functions.

  7. Harnessing isomerization-mediated manipulation of nonspecific cell/matrix interactions to reversibly trigger and suspend stem cell differentiation.

    Science.gov (United States)

    Bai, Tao; Sinclair, Andrew; Sun, Fang; Jain, Priyesh; Hung, Hsiang-Chieh; Zhang, Peng; Ella-Menye, Jean-Rene; Liu, Wenguang; Jiang, Shaoyi

    2016-01-01

    Specific protein-cell and drug-cell interactions have been widely used to manipulate stem cell fate. Despite extensive studies, most current platforms cannot realize reversible manipulation of stem cell differentiation. In this work, we report a photodynamic zwitterionic hydrogel capable of reversibly triggering and suspending the differentiation process via manipulating nonspecific interactions between cultured stem cells and the hydrogel. The differentiation state of stem cells can be altered by exposing the hydrogel to a selected light program, while differentiation can be immediately suspended when near-infrared exposure converts the hydrogel into a purely zwitterionic form. While many other studies apply specific interactions to control stem cell fate, this work provides a completely different approach-allowing reversible, real-time and localized manipulation of stem cell fate choice via nonspecific interactions.

  8. Co-Inflammatory Roles of TGFβ1 in the Presence of TNFα Drive a Pro-inflammatory Fate in Mesenchymal Stem Cells

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    Shalom Lerrer

    2017-05-01

    factors that can affect other cells in their microenvironment and induce breast tumor cell elongation, migration, and scattering out of spheroid tumor masses. Thus, our findings demonstrate a TNFα + TGFβ1-driven pro-inflammatory fate in MSCs, identify specific molecular mechanisms involved, and propose that TNFα + TGFβ1-stimulated MSCs influence the tumor niche. These observations suggest key roles for the microenvironment in regulating MSC functions, which in turn may affect different health-related conditions.

  9. P2X7 Receptor as a Key Player in Oxidative Stress-Driven Cell Fate in Nonalcoholic Steatohepatitis

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    Saurabh Chatterjee

    2015-01-01

    Full Text Available Incidences of nonalcoholic fatty liver disease parallels increase in the global obesity epidemic. NAFLD has been shown to be associated with risks of cardiometabolic disorders and kidney disturbances. It is accompanied by insulin and leptin resistance that complicate the diagnosis and treatment of this public health menace. Though significant research is underway for understanding the molecular mechanisms of NAFLD and its subsequent inflammatory and fibrotic manifestations like nonalcoholic steatohepatitis, the role of purinergic receptors has been unclear. It is increasingly being recognized that damage associated molecular patterns like NAD and ATP that are released from injured cells via hepatocellular injury either by oxidative stress or lipotoxicity from steatosis activate the purinergic receptor. Based on evidence from inflammatory responses in the airways and vasculature and autoimmune complications in humans and rodents, it is beyond doubt that hepatocellular inflammation such as that seen in NASH can result from the activation of purinergic receptors. This event can result in the formation of inflammasomes and can be an important pathway for the progression of NASH. The present review evaluates the current knowledge of the role of oxidative stress and its signaling via P2X7 receptors in hepatocellular injury that might contribute to the NASH pathophysiology.

  10. Sympathetic Innervation Promotes Arterial Fate by Enhancing Endothelial ERK Activity.

    Science.gov (United States)

    Pardanaud, Luc; Pibouin-Fragner, Laurence; Dubrac, Alexandre; Mathivet, Thomas; English, Isabel; Brunet, Isabelle; Simons, Michael; Eichmann, Anne

    2016-08-19

    Arterial endothelial cells are morphologically, functionally, and molecularly distinct from those found in veins and lymphatic vessels. How arterial fate is acquired during development and maintained in adult vessels is incompletely understood. We set out to identify factors that promote arterial endothelial cell fate in vivo. We developed a functional assay, allowing us to monitor and manipulate arterial fate in vivo, using arteries isolated from quails that are grafted into the coelom of chick embryos. Endothelial cells migrate out from the grafted artery, and their colonization of host arteries and veins is quantified. Here we show that sympathetic innervation promotes arterial endothelial cell fate in vivo. Removal of sympathetic nerves decreases arterial fate and leads to colonization of veins, whereas exposure to sympathetic nerves or norepinephrine imposes arterial fate. Mechanistically, sympathetic nerves increase endothelial ERK (extracellular signal-regulated kinase) activity via adrenergic α1 and α2 receptors. These findings show that sympathetic innervation promotes arterial endothelial fate and may lead to novel approaches to improve arterialization in human disease. © 2016 American Heart Association, Inc.

  11. miRNA suppression of a Notch repressor directs non-neuronal fate in Drosophila mechanosensory organs.

    Science.gov (United States)

    Kavaler, Joshua; Duan, Hong; Aradhya, Rajaguru; de Navas, Luis F; Joseph, Brian; Shklyar, Boris; Lai, Eric C

    2017-12-01

    Although there is abundant evidence that individual microRNA (miRNA) loci repress large cohorts of targets, large-scale knockout studies suggest that most miRNAs are phenotypically dispensable. Here, we identify a rare case of developmental cell specification that is highly dependent on miRNA control of an individual target. We observe that binary cell fate choice in the Drosophila melanogaster peripheral sensory organ lineage is controlled by the non-neuronally expressed mir-279/996 cluster, with a majority of notum sensory organs exhibiting transformation of sheath cells into ectopic neurons. The mir-279/996 defect phenocopies Notch loss of function during the sheath-neuron cell fate decision, suggesting the miRNAs facilitate Notch signaling. Consistent with this, mir-279/996 knockouts are strongly enhanced by Notch heterozygosity, and activated nuclear Notch is impaired in the miRNA mutant. Although Hairless (H) is the canonical nuclear Notch pathway inhibitor, and H heterozygotes exhibit bristle cell fate phenotypes reflecting gain-of-Notch signaling, H/+ does not rescue mir-279/996 mutants. Instead, we identify Insensible (Insb), another neural nuclear Notch pathway inhibitor, as a critical direct miR-279/996 target. Insb is posttranscriptionally restricted to neurons by these miRNAs, and its heterozygosity strongly suppresses ectopic peripheral nervous system neurons in mir-279/996 mutants. Thus, proper assembly of multicellular mechanosensory organs requires a double-negative circuit involving miRNA-mediated suppression of a Notch repressor to assign non-neuronal cell fate. © 2018 Kavaler et al.

  12. Choices for Induction of Pluripotency: Recent Developments in Human Induced Pluripotent Stem Cell Reprogramming Strategies

    NARCIS (Netherlands)

    Brouwer, M.; Zhou, Huiqing; Nadif Kasri, N.

    2016-01-01

    The ability to generate human induced pluripotent stem cells (iPSCs) from somatic cells provides tremendous promises for regenerative medicine and its use has widely increased over recent years. However, reprogramming efficiencies remain low and chromosomal instability and tumorigenic potential are

  13. Cell-cycle fate-monitoring distinguishes individual chemosensitive and chemoresistant cancer cells in drug-treated heterogeneous populations demonstrated by real-time FUCCI imaging.

    Science.gov (United States)

    Miwa, Shinji; Yano, Shuya; Kimura, Hiroaki; Yamamoto, Mako; Toneri, Makoto; Matsumoto, Yasunori; Uehara, Fuminari; Hiroshima, Yukihiko; Murakami, Takashi; Hayashi, Katsuhiro; Yamamoto, Norio; Bouvet, Michael; Fujiwara, Toshiyoshi; Tsuchiya, Hiroyuki; Hoffman, Robert M

    2015-01-01

    Essentially every population of cancer cells within a tumor is heterogeneous, especially with regard to chemosensitivity and resistance. In the present study, we utilized the fluorescence ubiquitination-based cell cycle indicator (FUCCI) imaging system to investigate the correlation between cell-cycle behavior and apoptosis after treatment of cancer cells with chemotherapeutic drugs. HeLa cells expressing FUCCI were treated with doxorubicin (DOX) (5 μM) or cisplatinum (CDDP) (5 μM) for 3 h. Cell-cycle progression and apoptosis were monitored by time-lapse FUCCI imaging for 72 h. Time-lapse FUCCI imaging demonstrated that both DOX and CDDP could induce cell cycle arrest in S/G2/M in almost all the cells, but a subpopulation of the cells could escape the block and undergo mitosis. The subpopulation which went through mitosis subsequently underwent apoptosis, while the cells arrested in S/G2/M survived. The present results demonstrate that chemoresistant cells can be readily identified in a heterogeneous population of cancer cells by S/G2/M arrest, which can serve in future studies as a visible target for novel agents that kill cell-cycle-arrested cells.

  14. Evaluation of the SCKnowIQ tool and reproductive CHOICES intervention among young adults with sickle cell disease or sickle cell trait.

    Science.gov (United States)

    Gallo, Agatha M; Wilkie, Diana J; Wang, Edward; Labotka, Richard J; Molokie, Robert E; Stahl, Christiane; Hershberger, Patricia E; Zhao, Zhongsheng; Suarez, Marie L; Johnson, Bonnye; Pullum, Cherese; Angulo, Rigoberto; Thompson, Alexis

    2014-08-01

    The study purpose was to evaluate a computer-based questionnaire (SCKnowIQ) and CHOICES educational intervention using cognitive interviewing with childbearing-aged people with sickle cell disease (SCD) or trait (SCT). Ten control group participants completed the SCKnowIQ twice. Ten intervention group participants completed the SCKnowIQ before and after the CHOICES intervention. Most participants found the questionnaire items appropriate and responded to items as the investigators intended. Participants' responses indicated that the information on SCD and SCT and reproductive options was understandable, balanced, important, and new to some. Internal consistency and test-retest reliability were adequate (.47 to .87) for 4 of the 6 scales, with significant within-group changes in knowledge scores for the intervention group but not for the control group. Findings show evidence for potential efficacy of the intervention, but proof of efficacy requires a larger randomized study. © The Author(s) 2013.

  15. The receptor-like kinases GSO1 and GSO2 together regulate root growth in Arabidopsis through control of cell division and cell fate specification.

    Science.gov (United States)

    Racolta, Adriana; Bryan, Anthony C; Tax, Frans E

    2014-02-01

    The root apical meristem of Arabidopsis is established post-embryonically as the main source of root cells, and its activity is maintained by complex bidirectional signaling between stem cells and mature cells. The receptor-like kinases GASSHO1 (GSO1) and GSO2 have been shown to regulate aerial epidermal function and seedling growth in Arabidopsis. Here we show that gso1; gso2 seedlings also have root growth and patterning defects. Analyses of mutant root morphology indicate abnormal numbers of cells in longitudinal files and radial cell layers, as well as aberrant stem cell division planes. gso1; gso2 double mutants misexpress markers for stem cells and differentiated root cell types. In addition, gso1; gso2 root growth defects, but not marker missexpression or patterning phenotypes, are rescued by growth on media containing metabolizable sugars. We conclude that GSO1 and GSO2 function together in intercellular signaling to positively regulate cell proliferation, differentiation of root cell types, and stem cell identity. In addition, GSO1 and GSO2 control seedling root growth by modulating sucrose response after germination. Copyright © 2013 Wiley Periodicals, Inc.

  16. Overcoming CD4 Th1 Cell Fate Restrictions to Sustain Antiviral CD8 T Cells and Control Persistent Virus Infection

    Directory of Open Access Journals (Sweden)

    Laura M. Snell

    2016-09-01

    Full Text Available Viral persistence specifically inhibits CD4 Th1 responses and promotes Tfh immunity, but the mechanisms that suppress Th1 cells and the disease consequences of their loss are unclear. Here, we demonstrate that the loss of CD4 Th1 cells specifically leads to progressive CD8 T cell decline and dysfunction during viral persistence. Therapeutically reconstituting CD4 Th1 cells restored CD4 T cell polyfunctionality, enhanced antiviral CD8 T cell numbers and function, and enabled viral control. Mechanistically, combined interaction of PD-L1 and IL-10 by suppressive dendritic cell subsets inhibited new CD4 Th1 cells in both acute and persistent virus infection, demonstrating an unrecognized suppressive function for PD-L1 in virus infection. Thus, the loss of CD4 Th1 cells is a key event leading to progressive CD8 T cell demise during viral persistence with important implications for restoring antiviral CD8 T cell immunity to control persistent viral infection.

  17. Chloroformate derivatization for tracing the fate of Amino acids in cells and tissues by multiple stable isotope resolved metabolomics (mSIRM).

    Science.gov (United States)

    Yang, Ye; Fan, Teresa W-M; Lane, Andrew N; Higashi, Richard M

    2017-07-11

    applied this method to profile amino acids and their labeling patterns in 13 C and 2 H doubly labeled PC9 cell extracts, cancerous and non-cancerous tissue extracts from a lung cancer patient and their protein hydrolysates as well as plasma extracts from mice fed with a liquid diet containing 13 C 6 -glucose (Glc). The multi-element isotopologue distributions provided key insights into amino acid metabolism and intracellular pools in human lung cancer tissues in high detail. The 13 C labeling of Asp and Glu revealed de novo synthesis of these amino acids from 13 C 6 -Glc via the Krebs cycle, specifically the elevated level of 13 C 3 -labeled Asp and Glu in cancerous versus non-cancerous lung tissues was consistent with enhanced pyruvate carboxylation. In addition, tracking the fate of double tracers, ( 13 C 6 -Glc +  2 H 2 -Gly or 13 C 6 -Glc +  2 H 3 -Ser) in PC9 cells clearly resolved pools of Ser and Gly synthesized de novo from 13 C 6 -Glc ( 13 C 3 -Ser and 13 C 2 -Gly) versus Ser and Gly derived from external sources ( 2 H 3 -Ser, 2 H 2 -Gly). Moreover the complex 2 H labeling patter