WorldWideScience

Sample records for cell fate control

  1. Asymmetric cell division during T cell development controls downstream fate

    Science.gov (United States)

    Pham, Kim; Shimoni, Raz; Charnley, Mirren; Ludford-Menting, Mandy J.; Hawkins, Edwin D.; Ramsbottom, Kelly; Oliaro, Jane; Izon, David; Ting, Stephen B.; Reynolds, Joseph; Lythe, Grant; Molina-Paris, Carmen; Melichar, Heather; Robey, Ellen; Humbert, Patrick O.; Gu, Min

    2015-01-01

    During mammalian T cell development, the requirement for expansion of many individual T cell clones, rather than merely expansion of the entire T cell population, suggests a possible role for asymmetric cell division (ACD). We show that ACD of developing T cells controls cell fate through differential inheritance of cell fate determinants Numb and α-Adaptin. ACD occurs specifically during the β-selection stage of T cell development, and subsequent divisions are predominantly symmetric. ACD is controlled by interaction with stromal cells and chemokine receptor signaling and uses a conserved network of polarity regulators. The disruption of polarity by deletion of the polarity regulator, Scribble, or the altered inheritance of fate determinants impacts subsequent fate decisions to influence the numbers of DN4 cells arising after the β-selection checkpoint. These findings indicate that ACD enables the thymic microenvironment to orchestrate fate decisions related to differentiation and self-renewal. PMID:26370500

  2. Control of stem cell fate by engineering their micro andnanoenvironment

    Institute of Scientific and Technical Information of China (English)

    Michelle F Griffin; Peter E Butler; Alexander M Seifalian; Deepak M Kalaskar

    2015-01-01

    Stem cells are capable of long-term self-renewal anddifferentiation into specialised cell types, making theman ideal candidate for a cell source for regenerativemedicine. The control of stem cell fate has become amajor area of interest in the field of regenerative medicineand therapeutic intervention. Conventional methodsof chemically inducing stem cells into specific lineagesis being challenged by the advances in biomaterialtechnology, with evidence highlighting that materialproperties are capable of driving stem cell fate. Materialsare being designed to mimic the clues stem cells receivein their in vivo stem cell niche including topographicaland chemical instructions. Nanotopographical clues thatmimic the extracellular matrix (ECM) in vivo have shownto regulate stem cell differentiation. The delivery of ECMcomponents on biomaterials in the form of short peptidessequences has also proved successful in directing stem celllineage. Growth factors responsible for controlling stemcell fate in vivo have also been delivered via biomaterialsto provide clues to determine stem cell differentiation. Analternative approach to guide stem cells fate is to providegenetic clues including delivering DNA plasmids andsmall interfering RNAs via scaffolds. This review, aims toprovide an overview of the topographical, chemical andmolecular clues that biomaterials can provide to guidestem cell fate. The promising features and challenges ofsuch approaches will be highlighted, to provide directionsfor future advancements in this exciting area of stem celltranslation for regenerative medicine.

  3. 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...

  4. Cell fate control in the developing central nervous system

    Energy Technology Data Exchange (ETDEWEB)

    Guérout, Nicolas; Li, Xiaofei; Barnabé-Heider, Fanie, E-mail: Fanie.Barnabe-Heider@ki.se

    2014-02-01

    The principal neural cell types forming the mature central nervous system (CNS) are now understood to be diverse. This cellular subtype diversity originates to a large extent from the specification of the earlier proliferating progenitor populations during development. Here, we review the processes governing the differentiation of a common neuroepithelial cell progenitor pool into mature neurons, astrocytes, oligodendrocytes, ependymal cells and adult stem cells. We focus on studies performed in mice and involving two distinct CNS structures: the spinal cord and the cerebral cortex. Understanding the origin, specification and developmental regulators of neural cells will ultimately impact comprehension and treatments of neurological disorders and diseases. - Highlights: • Similar mechanisms regulate cell fate in different CNS cell types and structures. • Cell fate regulators operate in a spatial–temporal manner. • Different neural cell types rely on the generation of a diversity of progenitor cells. • Cell fate decision is dictated by the integration of intrinsic and extrinsic signals.

  5. 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...

  6. 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...

  7. 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.

  8. lin-28 controls the succession of cell fate choices via two distinct activities.

    Directory of Open Access Journals (Sweden)

    Bhaskar Vadla

    Full Text Available lin-28 is a conserved regulator of cell fate succession in animals. In Caenorhabditis elegans, it is a component of the heterochronic gene pathway that governs larval developmental timing, while its vertebrate homologs promote pluripotency and control differentiation in diverse tissues. The RNA binding protein encoded by lin-28 can directly inhibit let-7 microRNA processing by a novel mechanism that is conserved from worms to humans. We found that C. elegans LIN-28 protein can interact with four distinct let-7 family pre-microRNAs, but in vivo inhibits the premature accumulation of only let-7. Surprisingly, however, lin-28 does not require let-7 or its relatives for its characteristic promotion of second larval stage cell fates. In other words, we find that the premature accumulation of mature let-7 does not account for lin-28's precocious phenotype. To explain let-7's role in lin-28 activity, we provide evidence that lin-28 acts in two steps: first, the let-7-independent positive regulation of hbl-1 through its 3'UTR to control L2 stage-specific cell fates; and second, a let-7-dependent step that controls subsequent fates via repression of lin-41. Our evidence also indicates that let-7 functions one stage earlier in C. elegans development than previously thought. Importantly, lin-28's two-step mechanism resembles that of the heterochronic gene lin-14, and the overlap of their activities suggests a clockwork mechanism for developmental timing. Furthermore, this model explains the previous observation that mammalian Lin28 has two genetically separable activities. Thus, lin-28's two-step mechanism may be an essential feature of its evolutionarily conserved role in cell fate succession.

  9. 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.

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

    Science.gov (United States)

    2015-11-04

    changes. We applied our method to build biosensors for diverse ligands and determine consensus sequences that enable ligand-responsive tertiary...performed without human interruption. We have done control selections on naïve libraries for theophylline biosensors , and demonstrated that the method can

  11. 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.

  12. The Let-60 Locus Controls the Switch between Vulval and Nonvulval Cell Fates in Caenorhabditis Elegans

    Science.gov (United States)

    Han, M.; Aroian, R. V.; Sternberg, P. W.

    1990-01-01

    During induction of the Caenorhabditis elegans hermaphrodite vulva by the anchor cell of the gonad, six multipotent vulval precursor cells (VPCs) have two distinct fates: three VPCs generate the vulva and the other three VPCs generate nonspecialized hypodermis. Genes that control the fates of the VPCs in response to the anchor cell signal are defined by mutations that cause all six VPCs to generate vulval tissue (Multivulva or Muv) or that cause all six VPCs to generate hypodermis (Vulvaless or Vul). Seven dominant Vul mutations were isolated as dominant suppressors of a lin-15 Muv mutation. These mutations are dominant alleles of the gene let-60, previously identified only by recessive lethal mutations. Our genetic studies of these dominant Vul recessive lethal mutations, recessive lethal mutations, intragenic revertants of the dominant Vul mutations, and the closely mapping semidominant multivulva lin-34 mutations suggest that: (1) loss-of-function mutations of let-60 are recessive lethal at a larval stage, but they also cause a Vul phenotype if the lethality is rescued maternally by a lin-34 gain-of-function mutation. (2) The dominant Vul alleles of let-60 are dominant negative mutations whose gene products compete with wild-type activity. (3) lin-34 semidominant Muv alleles are either gain-of-function mutations of let-60 or gain-of-function mutations of an intimately related gene that elevates let-60 activity. We propose that let-60 activity controls VPC fates. In a wild-type animal, reception by a VPC of inductive signal activates let-60, and it generates into a vulval cell type; in absence of inductive signal, let-60 activity is low and the VPC generates hypodermal cells. Our genetic interaction studies suggest that let-60 acts downstream of let-23 and lin-15 and upstream of lin-1 and lin-12 in the genetic pathway specifying the switch between vulval and nonvulval cell types. PMID:2076820

  13. Neuronal cell fate diversification controlled by sub-temporal action of Kruppel

    Science.gov (United States)

    Stratmann, Johannes; Gabilondo, Hugo; Benito-Sipos, Jonathan; Thor, Stefan

    2016-01-01

    During Drosophila embryonic nervous system development, neuroblasts express a programmed cascade of five temporal transcription factors that govern the identity of cells generated at different time-points. However, these five temporal genes fall short of accounting for the many distinct cell types generated in large lineages. Here, we find that the late temporal gene castor sub-divides its large window in neuroblast 5–6 by simultaneously activating two cell fate determination cascades and a sub-temporal regulatory program. The sub-temporal program acts both upon itself and upon the determination cascades to diversify the castor window. Surprisingly, the early temporal gene Kruppel acts as one of the sub-temporal genes within the late castor window. Intriguingly, while the temporal gene castor activates the two determination cascades and the sub-temporal program, spatial cues controlling cell fate in the latter part of the 5–6 lineage exclusively act upon the determination cascades. DOI: http://dx.doi.org/10.7554/eLife.19311.001 PMID:27740908

  14. A BMP regulatory network controls ectodermal cell fate decisions at the neural plate border.

    Science.gov (United States)

    Reichert, Sabine; Randall, Rebecca A; Hill, Caroline S

    2013-11-01

    During ectodermal patterning the neural crest and preplacodal ectoderm are specified in adjacent domains at the neural plate border. BMP signalling is required for specification of both tissues, but how it is spatially and temporally regulated to achieve this is not understood. Here, using a transgenic zebrafish BMP reporter line in conjunction with double-fluorescent in situ hybridisation, we show that, at the beginning of neurulation, the ventral-to-dorsal gradient of BMP activity evolves into two distinct domains at the neural plate border: one coinciding with the neural crest and the other abutting the epidermis. In between is a region devoid of BMP activity, which is specified as the preplacodal ectoderm. We identify the ligands required for these domains of BMP activity. We show that the BMP-interacting protein Crossveinless 2 is expressed in the BMP activity domains and is under the control of BMP signalling. We establish that Crossveinless 2 functions at this time in a positive-feedback loop to locally enhance BMP activity, and show that it is required for neural crest fate. We further demonstrate that the Distal-less transcription factors Dlx3b and Dlx4b, which are expressed in the preplacodal ectoderm, are required for the expression of a cell-autonomous BMP inhibitor, Bambi-b, which can explain the specific absence of BMP activity in the preplacodal ectoderm. Taken together, our data define a BMP regulatory network that controls cell fate decisions at the neural plate border.

  15. 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.

  16. Optogenetic Control of Nodal Signaling Reveals a Temporal Pattern of Nodal Signaling Regulating Cell Fate Specification during Gastrulation.

    Science.gov (United States)

    Sako, Keisuke; Pradhan, Saurabh J; Barone, Vanessa; Inglés-Prieto, Álvaro; Müller, Patrick; Ruprecht, Verena; Čapek, Daniel; Galande, Sanjeev; Janovjak, Harald; Heisenberg, Carl-Philipp

    2016-07-19

    During metazoan development, the temporal pattern of morphogen signaling is critical for organizing cell fates in space and time. Yet, tools for temporally controlling morphogen signaling within the embryo are still scarce. Here, we developed a photoactivatable Nodal receptor to determine how the temporal pattern of Nodal signaling affects cell fate specification during zebrafish gastrulation. By using this receptor to manipulate the duration of Nodal signaling in vivo by light, we show that extended Nodal signaling within the organizer promotes prechordal plate specification and suppresses endoderm differentiation. Endoderm differentiation is suppressed by extended Nodal signaling inducing expression of the transcriptional repressor goosecoid (gsc) in prechordal plate progenitors, which in turn restrains Nodal signaling from upregulating the endoderm differentiation gene sox17 within these cells. Thus, optogenetic manipulation of Nodal signaling identifies a critical role of Nodal signaling duration for organizer cell fate specification during gastrulation.

  17. Optogenetic Control of Nodal Signaling Reveals a Temporal Pattern of Nodal Signaling Regulating Cell Fate Specification during Gastrulation

    Directory of Open Access Journals (Sweden)

    Keisuke Sako

    2016-07-01

    Full Text Available During metazoan development, the temporal pattern of morphogen signaling is critical for organizing cell fates in space and time. Yet, tools for temporally controlling morphogen signaling within the embryo are still scarce. Here, we developed a photoactivatable Nodal receptor to determine how the temporal pattern of Nodal signaling affects cell fate specification during zebrafish gastrulation. By using this receptor to manipulate the duration of Nodal signaling in vivo by light, we show that extended Nodal signaling within the organizer promotes prechordal plate specification and suppresses endoderm differentiation. Endoderm differentiation is suppressed by extended Nodal signaling inducing expression of the transcriptional repressor goosecoid (gsc in prechordal plate progenitors, which in turn restrains Nodal signaling from upregulating the endoderm differentiation gene sox17 within these cells. Thus, optogenetic manipulation of Nodal signaling identifies a critical role of Nodal signaling duration for organizer cell fate specification during gastrulation.

  18. BMP-SHH signaling network controls epithelial stem cell fate via regulation of its niche in the developing tooth.

    Science.gov (United States)

    Li, Jingyuan; Feng, Jifan; Liu, Yang; Ho, Thach-Vu; Grimes, Weston; Ho, Hoang Anh; Park, Shery; Wang, Songlin; Chai, Yang

    2015-04-20

    During embryogenesis, ectodermal stem cells adopt different fates and form diverse ectodermal organs, such as teeth, hair follicles, mammary glands, and salivary glands. Interestingly, these ectodermal organs differ in their tissue homeostasis, which leads to differential abilities for continuous growth postnatally. Mouse molars lose the ability to grow continuously, whereas incisors retain this ability. In this study, we found that a BMP-Smad4-SHH-Gli1 signaling network may provide a niche supporting transient Sox2+ dental epithelial stem cells in mouse molars. This mechanism also plays a role in continuously growing mouse incisors. The differential fate of epithelial stem cells in mouse molars and incisors is controlled by this BMP/SHH signaling network, which partially accounts for the different postnatal growth potential of molars and incisors. Collectively, our study highlights the importance of crosstalk between two signaling pathways, BMP and SHH, in regulating the fate of epithelial stem cells during organogenesis.

  19. Role of PUF-8/PUF protein in stem cell control, sperm-oocyte decision and cell fate reprogramming.

    Science.gov (United States)

    Datla, Udaya Sree; Scovill, Natasha Carol; Brokamp, Austin J; Kim, Eunsuk; Asch, Adam S; Lee, Myon-Hee

    2014-10-01

    Pumilio and FBF (PUF) proteins are conserved stem cell regulators that maintain germline stem cells (GSCs) in worms and flies. Moreover, they are also present in vertebrate stem cells. The nematode Caenorhabditis elegans has multiple PUF proteins with specialized roles. Among them, PUF-8 protein controls multiple cellular processes, including proliferation, differentiation, sperm-oocyte decision, and cell fate reprogramming, depending on the genetic context in the C. elegans germline. In this review, we describe the possible mechanisms of how PUF-8 protein systematically controls multiple cellular processes in the C. elegans germline. Since PUF proteins are evolutionarily conserved, we suggest that a similar mechanism may be involved in controlling stem cell regulation and differentiation in other organisms, including humans.

  20. Protein Kinase B Controls Transcriptional Programs that Direct Cytotoxic T Cell Fate but Is Dispensable for T Cell Metabolism

    Science.gov (United States)

    Macintyre, Andrew N.; Finlay, David; Preston, Gavin; Sinclair, Linda V.; Waugh, Caryll M.; Tamas, Peter; Feijoo, Carmen; Okkenhaug, Klaus; Cantrell, Doreen A.

    2011-01-01

    Summary In cytotoxic T cells (CTL), Akt, also known as protein kinase B, is activated by the T cell antigen receptor (TCR) and the cytokine interleukin 2 (IL-2). Akt can control cell metabolism in many cell types but whether this role is important for CTL function has not been determined. Here we have shown that Akt does not mediate IL-2- or TCR-induced cell metabolic responses; rather, this role is assumed by other Akt-related kinases. There is, however, a nonredundant role for sustained and strong activation of Akt in CTL to coordinate the TCR- and IL-2-induced transcriptional programs that control expression of key cytolytic effector molecules, adhesion molecules, and cytokine and chemokine receptors that distinguish effector versus memory and naive T cells. Akt is thus dispensable for metabolism, but the strength and duration of Akt activity dictates the CTL transcriptional program and determines CTL fate. PMID:21295499

  1. SCARECROW-LIKE23 and SCARECROW jointly specify endodermal cell fate but distinctly control SHORT-ROOT movement.

    Science.gov (United States)

    Long, Yuchen; Goedhart, Joachim; Schneijderberg, Martinus; Terpstra, Inez; Shimotohno, Akie; Bouchet, Benjamin P; Akhmanova, Anna; Gadella, Theodorus W J; Heidstra, Renze; Scheres, Ben; Blilou, Ikram

    2015-11-01

    Intercellular signaling through trafficking of regulatory proteins is a widespread phenomenon in plants and can deliver positional information for the determination of cell fate. In the Arabidopsis root meristem, the cell fate determinant SHORT-ROOT (SHR), a GRAS domain transcription factor, acts as a signaling molecule from the stele to the adjacent layer to specify endodermal cell fate. Upon exiting the stele, SHR activates another GRAS domain transcription factor, SCARCROW (SCR), which, together with several BIRD/INDETERMINATE DOMAIN proteins, restricts movement of SHR to define a single cell layer of endodermis. Here we report that endodermal cell fate also requires the joint activity of both SCR and its closest homologue SCARECROW-LIKE23 (SCL23). We show that SCL23 protein moves with zonation-dependent directionality. Within the meristem, SCL23 exhibits short-ranged movement from ground tissue to vasculature. Away from the meristem, SCL23 displays long-range rootward movement into meristematic vasculature and a bidirectional radial spread, respectively. As a known target of SHR and SCR, SCL23 also interacts with SCR and SHR and can restrict intercellular outspread of SHR without relying on nuclear retention as SCR does. Collectively, our data show that SCL23 is a mobile protein that controls movement of SHR and acts redundantly with SCR to specify endodermal fate in the root meristem.

  2. Activin and GDF11 collaborate in feedback control of neuroepithelial stem cell proliferation and fate

    Science.gov (United States)

    Gokoffski, Kimberly K.; Wu, Hsiao-Huei; Beites, Crestina L.; Kim, Joon; Kim, Euiseok J.; Matzuk, Martin M.; Johnson, Jane E.; Lander, Arthur D.; Calof, Anne L.

    2011-01-01

    Studies of the olfactory epithelium model system have demonstrated that production of neurons is regulated by negative feedback. Previously, we showed that a locally produced signal, the TGFβ superfamily ligand GDF11, regulates the genesis of olfactory receptor neurons by inhibiting proliferation of the immediate neuronal precursors (INPs) that give rise to them. GDF11 is antagonized by follistatin (FST), which is also produced locally. Here, we show that Fst–/– mice exhibit dramatically decreased neurogenesis, a phenotype that can only be partially explained by increased GDF11 activity. Instead, a second FST-binding factor, activin βB (ACTβB), inhibits neurogenesis by a distinct mechanism: whereas GDF11 inhibits expansion of INPs, ACTβB inhibits expansion of stem and early progenitor cells. We present data supporting the concept that these latter cells, previously considered two distinct types, constitute a dynamic stem/progenitor population in which individual cells alternate expression of Sox2 and/or Ascl1. In addition, we demonstrate that interplay between ACTβB and GDF11 determines whether stem/progenitor cells adopt a glial versus neuronal fate. Altogether, the data indicate that the transition between stem cells and committed progenitors is neither sharp nor irreversible and that GDF11, ACTβB and FST are crucial components of a circuit that controls both total cell number and the ratio of neuronal versus glial cells in this system. Thus, our findings demonstrate a close connection between the signals involved in the control of tissue size and those that regulate the proportions of different cell types. PMID:21852401

  3. The neural crest stem cells: control of neural crest cell fate and plasticity by endothelin-3

    Directory of Open Access Journals (Sweden)

    ELISABETH DUPIN

    2001-12-01

    Full Text Available How the considerable diversity of neural crest (NC-derived cell types arises in the vertebrate embryo has long been a key question in developmental biology. The pluripotency and plasticity of differentiation of the NC cell population has been fully documented and it is well-established that environmental cues play an important role in patterning the NC derivatives throughout the body. Over the past decade, in vivo and in vitro cellular approaches have unravelled the differentiation potentialities of single NC cells and led to the discovery of NC stem cells. Although it is clear that the final fate of individual cells is in agreement with their final position within the embryo, it has to be stressed that the NC cells that reach target sites are pluripotent and further restrictions occur only late in development. It is therefore a heterogenous collection of cells that is submitted to local environmental signals in the various NC-derived structures. Several factors were thus identified which favor the development of subsets of NC-derived cells in vitro. Moreover, the strategy of gene targeting in mouse has led at identifying new molecules able to control one or several aspects of NC cell differentiation in vivo. Endothelin peptides (and endothelin receptors are among those. The conjunction of recent data obtained in mouse and avian embryos and reviewed here contributes to a better understanding of the action of the endothelin signaling pathway in the emergence and stability of NC-derived cell phenotypes.O modo como a diversidade dos tipos celulares derivados da crista neural (CN surge, no embrião de vertebrado, tem sido uma pergunta chave na biologia do desenvolvimento. A pluripotência e a plasticidade na diferenciação da população de células da CN têm sido intensivamente documentadas, ficando deste modo estabelecido que os factores ambientais têm um papel importante na correta diferenciação dos derivados da CN no organismo. Na d

  4. Eya1 controls cell polarity, spindle orientation, cell fate and Notch signaling in distal embryonic lung epithelium.

    Science.gov (United States)

    El-Hashash, Ahmed H K; Turcatel, Gianluca; Al Alam, Denise; Buckley, Sue; Tokumitsu, Hiroshi; Bellusci, Saverio; Warburton, David

    2011-04-01

    Cell polarity, mitotic spindle orientation and asymmetric division play a crucial role in the self-renewal/differentiation of epithelial cells, yet little is known about these processes and the molecular programs that control them in embryonic lung distal epithelium. Herein, we provide the first evidence that embryonic lung distal epithelium is polarized with characteristic perpendicular cell divisions. Consistent with these findings, spindle orientation-regulatory proteins Insc, LGN (Gpsm2) and NuMA, and the cell fate determinant Numb are asymmetrically localized in embryonic lung distal epithelium. Interfering with the function of these proteins in vitro randomizes spindle orientation and changes cell fate. We further show that Eya1 protein regulates cell polarity, spindle orientation and the localization of Numb, which inhibits Notch signaling. Hence, Eya1 promotes both perpendicular division as well as Numb asymmetric segregation to one daughter in mitotic distal lung epithelium, probably by controlling aPKCζ phosphorylation. Thus, epithelial cell polarity and mitotic spindle orientation are defective after interfering with Eya1 function in vivo or in vitro. In addition, in Eya1(-/-) lungs, perpendicular division is not maintained and Numb is segregated to both daughter cells in mitotic epithelial cells, leading to inactivation of Notch signaling. As Notch signaling promotes progenitor cell identity at the expense of differentiated cell phenotypes, we test whether genetic activation of Notch could rescue the Eya1(-/-) lung phenotype, which is characterized by loss of epithelial progenitors, increased epithelial differentiation but reduced branching. Indeed, genetic activation of Notch partially rescues Eya1(-/-) lung epithelial defects. These findings uncover novel functions for Eya1 as a crucial regulator of the complex behavior of distal embryonic lung epithelium.

  5. Controlling Cell Functions and Fate with Surfaces and Hydrogels: The Role of Material Features in Cell Adhesion and Signal Transduction

    Directory of Open Access Journals (Sweden)

    Maurizio Ventre

    2016-03-01

    Full Text Available In their natural environment, cells are constantly exposed to a cohort of biochemical and biophysical signals that govern their functions and fate. Therefore, materials for biomedical applications, either in vivo or in vitro, should provide a replica of the complex patterns of biological signals. Thus, the development of a novel class of biomaterials requires, on the one side, the understanding of the dynamic interactions occurring at the interface of cells and materials; on the other, it requires the development of technologies able to integrate multiple signals precisely organized in time and space. A large body of studies aimed at investigating the mechanisms underpinning cell-material interactions is mostly based on 2D systems. While these have been instrumental in shaping our understanding of the recognition of and reaction to material stimuli, they lack the ability to capture central features of the natural cellular environment, such as dimensionality, remodelling and degradability. In this work, we review the fundamental traits of material signal sensing and cell response. We then present relevant technologies and materials that enable fabricating systems able to control various aspects of cell behavior, and we highlight potential differences that arise from 2D and 3D settings.

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

    Science.gov (United States)

    Mosqueira, Diogo; Pagliari, Stefania; Uto, Koichiro; Ebara, Mitsuhiro; Romanazzo, Sara; Escobedo-Lucea, Carmen; Nakanishi, Jun; Taniguchi, Akiyoshi; Franzese, Ornella; Di Nardo, Paolo; Goumans, Marie José; Traversa, Enrico; Pinto-do-Ó, Perpetua; Aoyagi, Takao; Forte, Giancarlo

    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.

  7. 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.

  8. A transcription factor network controls cell migration and fate decisions in the developing zebrafish pineal complex

    Science.gov (United States)

    Clanton, Joshua A.; Dean, Benjamin J.; Gamse, Joshua T.

    2016-01-01

    The zebrafish pineal complex consists of four cell types (rod and cone photoreceptors, projection neurons and parapineal neurons) that are derived from a single pineal complex anlage. After specification, parapineal neurons migrate unilaterally away from the rest of the pineal complex whereas rods, cones and projection neurons are non-migratory. The transcription factor Tbx2b is important for both the correct number and migration of parapineal neurons. We find that two additional transcription factors, Flh and Nr2e3, negatively regulate parapineal formation. Flh induces non-migratory neuron fates and limits the extent of parapineal specification, in part by activation of Nr2e3 expression. Tbx2b is positively regulated by Flh, but opposes Flh action during specification of parapineal neurons. Loss of parapineal neuron specification in Tbx2b-deficient embryos can be partially rescued by loss of Nr2e3 or Flh function; however, parapineal migration absolutely requires Tbx2b activity. We conclude that cell specification and migration in the pineal complex are regulated by a network of at least three transcription factors. PMID:27317804

  9. cis-Regulatory control of three cell fate-specific genes in vulval organogenesis of Caenorhabditis elegans and C. briggsae.

    Science.gov (United States)

    Kirouac, Martha; Sternberg, Paul W

    2003-05-01

    The great-grandprogeny of the Caenorhabditis elegans vulval precursor cells (VPCs) adopt one of the final vulA, B1, B2, C, D, E, and F cell fates in a precise spatial pattern. This pattern of vulval cell types is likely to depend on the cis-regulatory regions of the transcriptional targets of intercellular signals in vulval development. egl-17, zmp-1, and cdh-3 are expressed differentially in the developing vulva cells, providing a potential readout for different signaling pathways. To understand how such pathways interact to specify unique vulval cell types in a precise pattern, we have identified cis-regulatory regions sufficient to confer vulval cell type-specific regulation when fused in cis to the basal pes-10 promoter. We have identified the C. briggsae homologs of these three genes, with their corresponding control regions, and tested these regions in both C. elegans and C. briggsae. These regions of similarity in C. elegans and C. briggsae upstream of egl-17, zmp-1, and cdh-3 promote expression in vulval cells and the anchor cell (AC). By using the cis-regulatory analysis and phylogenetic footprinting, we have identified overrepresented sequences involved in conferring vulval and AC expression.

  10. 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

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

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    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.

  12. 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 compl

  13. SCARECROW, SCR-LIKE 23 and SHORT-ROOT control bundle sheath cell fate and function in Arabidopsis thaliana.

    Science.gov (United States)

    Cui, Hongchang; Kong, Danyu; Liu, Xiuwen; Hao, Yueling

    2014-04-01

    Bundle sheath (BS) cells form a single cell layer surrounding the vascular tissue in leaves. In C3 plants, photosynthesis occurs in both the BS and mesophyll cells, but the BS cells are the major sites of photosynthesis in C4 plants, whereas the mesophyll cells are only involved in CO2 fixation. Because C4 plants are more efficient photosynthetically, introduction of the C4 mechanism into C3 plants is considered a key strategy to improve crop yield. One prerequisite for such C3-to-C4 engineering is the ability to manipulate the number and physiology of the BS cells, but the molecular basis of BS cell-fate specification remains unclear. Here we report that mutations in three GRAS family transcription factors, SHORT-ROOT (SHR), SCARECROW (SCR) and SCARECROW-LIKE 23 (SCL23), affect BS cell fate in Arabidopsis thaliana. SCR and SCL23 are expressed specifically in the BS cells and act redundantly in BS cell-fate specification, but their expression pattern and function diverge at later stages of leaf development. Using ChIP-chip experiments and sugar assays, we show that SCR is primarily involved in sugar transport whereas SCL23 functions in mineral transport. SHR is also essential for BS cell-fate specification, but it is expressed in the central vascular tissue. However, the SHR protein moves into the BS cells, where it directly regulates SCR and SCL23 expression. SHR, SCR and SCL23 homologs are present in many plant species, suggesting that this developmental pathway for BS cell-fate specification is likely to be evolutionarily conserved.

  14. Fate mapping of dendritic cells

    Directory of Open Access Journals (Sweden)

    Barbara Ursula Schraml

    2015-05-01

    Full Text Available Dendritic cells (DCs are a heterogeneous group of mononuclear phagocytes with versatile roles in immunity. They are classified predominantly based on phenotypic and functional properties, namely their stellate morphology, expression of the integrin CD11c and major histocompatibility class II molecules, as well as their superior capacity to migrate to secondary lymphoid organs and stimulate naïve T cells. However, these attributes are not exclusive to DCs and often change within inflammatory or infectious environments. This led to debates over cell identification and questioned even the mere existence of DCs as distinct leukocyte lineage. Here, we review experimental approaches taken to fate map DCs and discuss how these have shaped our understanding of DC ontogeny and lineage affiliation. Considering the ontogenetic properties of DCs will help to overcome the inherent shortcomings of purely phenotypic- and function-based approaches to cell definition and will yield a more robust way of DC classification.

  15. Systems biology provides new insights into the molecular mechanisms that control the fate of embryonic stem cells.

    Science.gov (United States)

    Mallanna, Sunil K; Rizzino, Angie

    2012-01-01

    During the last 5 years there has been enormous progress in developing a deeper understanding of the molecular mechanisms that control the self-renewal and pluripotency of embryonic stem cells (ESC). Early progress resulted from studying individual transcription factors and signaling pathways. Unexpectedly, these studies demonstrated that small changes in the levels of master regulators, such as Oct4 and Sox2, promote the differentiation of ESC. More recently, impressive progress has been made using technologies that provide a global view of the signaling pathways and the gene regulatory networks that control the fate of ESC. This review provides an overview of the progress made using several different high-throughput technologies and focuses on proteomic studies, which provide the first glimpse of the protein-protein interaction networks used by ESC. The latter studies indicate that transcription factors required for the self-renewal of ESC are part of a large, highly integrated protein-protein interaction landscape, which helps explain why the levels of master regulators need to be regulated precisely in ESC.

  16. Caenorhabditis elegans vulval cell fate patterning

    Science.gov (United States)

    Félix, Marie-Anne

    2012-08-01

    The spatial patterning of three cell fates in a row of competent cells is exemplified by vulva development in the nematode Caenorhabditis elegans. The intercellular signaling network that underlies fate specification is well understood, yet quantitative aspects remain to be elucidated. Quantitative models of the network allow us to test the effect of parameter variation on the cell fate pattern output. Among the parameter sets that allow us to reach the wild-type pattern, two general developmental patterning mechanisms of the three fates can be found: sequential inductions and morphogen-based induction, the former being more robust to parameter variation. Experimentally, the vulval cell fate pattern is robust to stochastic and environmental challenges, and minor variants can be detected. The exception is the fate of the anterior cell, P3.p, which is sensitive to stochastic variation and spontaneous mutation, and is also evolving the fastest. Other vulval precursor cell fates can be affected by mutation, yet little natural variation can be found, suggesting stabilizing selection. Despite this fate pattern conservation, different Caenorhabditis species respond differently to perturbations of the system. In the quantitative models, different parameter sets can reconstitute their response to perturbation, suggesting that network variation among Caenorhabditis species may be quantitative. Network rewiring likely occurred at longer evolutionary scales.

  17. Switch Enhancers Interpret TGF-β and Hippo Signaling to Control Cell Fate in Human Embryonic Stem Cells

    Directory of Open Access Journals (Sweden)

    Tobias A. Beyer

    2013-12-01

    Full Text Available A small toolkit of morphogens is used repeatedly to direct development, raising the question of how context dictates interpretation of the same cue. One example is the transforming growth factor β (TGF-β pathway that in human embryonic stem cells fulfills two opposite functions: pluripotency maintenance and mesendoderm (ME specification. Using proteomics coupled to analysis of genome occupancy, we uncover a regulatory complex composed of transcriptional effectors of the Hippo pathway (TAZ/YAP/TEAD, the TGF-β pathway (SMAD2/3, and the pluripotency regulator OCT4 (TSO. TSO collaborates with NuRD repressor complexes to buffer pluripotency gene expression while suppressing ME genes. Importantly, the SMAD DNA binding partner FOXH1, a major specifier of ME, is found near TSO elements, and upon fate specification we show that TSO is disrupted with subsequent SMAD-FOXH1 induction of ME. These studies define switch-enhancer elements and provide a framework to understand how cellular context dictates interpretation of the same morphogen signal in development.

  18. Notch-HES1 signaling axis controls hemato-endothelial fate decisions of human embryonic and induced pluripotent stem cells.

    Science.gov (United States)

    Lee, Jung Bok; Werbowetski-Ogilvie, Tamra E; Lee, Jong-Hee; McIntyre, Brendan A S; Schnerch, Angelique; Hong, Seok-Ho; Park, In-Hyun; Daley, George Q; Bernstein, Irwin D; Bhatia, Mickie

    2013-08-15

    Notch signaling regulates several cellular processes including cell fate decisions and proliferation in both invertebrates and mice. However, comparatively less is known about the role of Notch during early human development. Here, we examined the function of Notch signaling during hematopoietic lineage specification from human pluripotent stem cells of both embryonic and adult fibroblast origin. Using immobilized Notch ligands and small interfering RNA to Notch receptors we have demonstrated that Notch1, but not Notch2, activation induced hairy and enhancer of split 1 (HES1) expression and generation of committed hematopoietic progenitors. Using gain- and loss-of-function approaches, this was shown to be attributed to Notch-signaling regulation through HES1, which dictated cell fate decisions from bipotent precursors either to the endothelial or hematopoietic lineages at the clonal level. Our study reveals a previously unappreciated role for the Notch pathway during early human hematopoiesis, whereby Notch signaling via HES1 represents a toggle switch of hematopoietic vs endothelial fate specification.

  19. 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.

  20. 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.

  1. Cell fate in the hand of Plk4

    NARCIS (Netherlands)

    Tanenbaum, Marvin E.; Medema, Rene H.

    2007-01-01

    The transcription factor Hand1 is required for cell-fate determination during placental development. Recent work shows that release of Hand1 from the nucleolus controls differentiation of trophoblast stem cells into trophoblast giant cells, and this switch is controlled by the antagonistic activitie

  2. 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.

  3. Towards a statistical mechanics of cell fate decisions.

    Science.gov (United States)

    Garcia-Ojalvo, Jordi; Martinez Arias, Alfonso

    2012-12-01

    The spatiotemporal organization of a developing organism requires carefully orchestrated sequences of cellular differentiation events. These events are triggered by decisions made by individual cells about their fate, which are in turn controlled by gene and protein regulation processes. While these cell fate decisions are subject to stochasticity and are not reproducible at the single-cell level, they result in highly consistent, almost deterministic patterns at the level of the whole cell population. The question of how this macroscopic order arises from a disordered microscopic behaviour is still outstanding, and is reminiscent of problems in physical systems that are readily addressed by statistical mechanics. Here we review recent studies that are beginning to provide the data needed to address this question and discuss conceptual ideas that might be used in a theoretical understanding of cell fate decision processes, emphasizing the challenges that biology poses to the application of statistical mechanics approaches to developmental biology.

  4. 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.

  5. MicroRNA-126-mediated control of cell fate in B-cell myeloid progenitors as a potential alternative to transcriptional factors.

    Science.gov (United States)

    Okuyama, Kazuki; Ikawa, Tomokatsu; Gentner, Bernhard; Hozumi, Katsuto; Harnprasopwat, Ratanakanit; Lu, Jun; Yamashita, Riu; Ha, Daon; Toyoshima, Takae; Chanda, Bidisha; Kawamata, Toyotaka; Yokoyama, Kazuaki; Wang, Shusheng; Ando, Kiyoshi; Lodish, Harvey F; Tojo, Arinobu; Kawamoto, Hiroshi; Kotani, Ai

    2013-08-13

    Lineage specification is thought to be largely regulated at the level of transcription, where lineage-specific transcription factors drive specific cell fates. MicroRNAs (miR), vital to many cell functions, act posttranscriptionally to decrease the expression of target mRNAs. MLL-AF4 acute lymphocytic leukemia exhibits both myeloid and B-cell surface markers, suggesting that the transformed cells are B-cell myeloid progenitor cells. Through gain- and loss-of-function experiments, we demonstrated that microRNA 126 (miR-126) drives B-cell myeloid biphenotypic leukemia differentiation toward B cells without changing expression of E2A immunoglobulin enhancer-binding factor E12/E47 (E2A), early B-cell factor 1 (EBF1), or paired box protein 5, which are critical transcription factors in B-lymphopoiesis. Similar induction of B-cell differentiation by miR-126 was observed in normal hematopoietic cells in vitro and in vivo in uncommitted murine c-Kit(+)Sca1(+)Lineage(-) cells, with insulin regulatory subunit-1 acting as a target of miR-126. Importantly, in EBF1-deficient hematopoietic progenitor cells, which fail to differentiate into B cells, miR-126 significantly up-regulated B220, and induced the expression of B-cell genes, including recombination activating genes-1/2 and CD79a/b. These data suggest that miR-126 can at least partly rescue B-cell development independently of EBF1. These experiments show that miR-126 regulates myeloid vs. B-cell fate through an alternative machinery, establishing the critical role of miRNAs in the lineage specification of multipotent mammalian cells.

  6. Connecting Mitochondria, Metabolism, and Stem Cell Fate.

    Science.gov (United States)

    Wanet, Anaïs; Arnould, Thierry; Najimi, Mustapha; Renard, Patricia

    2015-09-01

    As sites of cellular respiration and energy production, mitochondria play a central role in cell metabolism. Cell differentiation is associated with an increase in mitochondrial content and activity and with a metabolic shift toward increased oxidative phosphorylation activity. The opposite occurs during reprogramming of somatic cells into induced pluripotent stem cells. Studies have provided evidence of mitochondrial and metabolic changes during the differentiation of both embryonic and somatic (or adult) stem cells (SSCs), such as hematopoietic stem cells, mesenchymal stem cells, and tissue-specific progenitor cells. We thus propose to consider those mitochondrial and metabolic changes as hallmarks of differentiation processes. We review how mitochondrial biogenesis, dynamics, and function are directly involved in embryonic and SSC differentiation and how metabolic and sensing pathways connect mitochondria and metabolism with cell fate and pluripotency. Understanding the basis of the crosstalk between mitochondria and cell fate is of critical importance, given the promising application of stem cells in regenerative medicine. In addition to the development of novel strategies to improve the in vitro lineage-directed differentiation of stem cells, understanding the molecular basis of this interplay could lead to the identification of novel targets to improve the treatment of degenerative diseases.

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

    Directory of Open Access Journals (Sweden)

    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.

  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. Cell fate regulation in early mammalian development

    Science.gov (United States)

    Oron, Efrat; Ivanova, Natalia

    2012-08-01

    Preimplantation development in mammals encompasses a period from fertilization to implantation and results in formation of a blastocyst composed of three distinct cell lineages: epiblast, trophectoderm and primitive endoderm. The epiblast gives rise to the organism, while the trophectoderm and the primitive endoderm contribute to extraembryonic tissues that support embryo development after implantation. In many vertebrates, such as frog or fish, maternally supplied lineage determinants are partitioned within the egg. Cell cleavage that follows fertilization results in polarization of these factors between the individual blastomeres, which become restricted in their developmental fate. In contrast, the mouse oocyte and zygote lack clear polarity and, until the eight-cell stage, individual blastomeres retain the potential to form all lineages. How are cell lineages specified in the absence of a maternally supplied blueprint? This is a fundamental question in the field of developmental biology. The answer to this question lies in understanding the cell-cell interactions and gene networks involved in embryonic development prior to implantation and using this knowledge to create testable models of the developmental processes that govern cell fates. We provide an overview of classic and contemporary models of early lineage development in the mouse and discuss the emerging body of work that highlights similarities and differences between blastocyst development in the mouse and other mammalian species.

  10. 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.

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

    Science.gov (United States)

    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.

  12. Sonic Hedgehog Controls the Phenotypic Fate and Therapeutic Efficacy of Grafted Neural Precursor Cells in a Model of Nigrostriatal Neurodegeneration.

    Science.gov (United States)

    Madhavan, Lalitha; Daley, Brian F; Davidson, Beverly L; Boudreau, Ryan L; Lipton, Jack W; Cole-Strauss, Allyson; Steece-Collier, Kathy; Collier, Timothy J

    2015-01-01

    The expression of soluble growth and survival promoting factors by neural precursor cells (NPCs) is suggested to be a prominent mechanism underlying the protective and regenerative effects of these cells after transplantation. Nevertheless, how and to what extent specific NPC-expressed factors contribute to therapeutic effects is not well understood. Using RNA silencing, the current study investigated the roles of two donor NPC molecules, namely glial cell-line derived neurotrophic factor (GDNF) and sonic hedgehog (SHH), in the protection of substantia nigra dopamine neurons in rats treated with 6-hydroxydopamine (6-OHDA). Analyses indicate that as opposed to the knock-down of GDNF, SHH inhibition caused a profound decline in nigrostriatal neuroprotection. Further, SHH silencing also curbed endogenous neurogenesis and the migration of host brdU+/dcx+ neural precursors into the striatum, which was present in the animals receiving control or GDNF silenced NPCs. A change in graft phenotype, mainly reflected by a reduced proportion of undifferentiated nestin+ cells, as well as a significantly greater host microglial activity, suggested an important role for these processes in the attenuation of neuroprotection and neurogenesis upon SHH silencing. Overall these studies reveal core mechanisms fundamental to grafted NPC-based therapeutic effects, and delineate the particular contributions of two graft-expressed molecules, SHH and GDNF, in mediating midbrain dopamine neuron protection, and host plasticity after NPC transplantation.

  13. Structure-function relationships in the stem cell's mechanical world A: seeding protocols as a means to control shape and fate of live stem cells.

    Science.gov (United States)

    Zimmermann, Joshua A; Knothe Tate, Melissa L

    2011-12-01

    Shape and fate are intrinsic manifestations of form and function at the cell scale. Here we hypothesize that seeding density and protocol affect the form and function of live embryonic murine mesenchymal stem cells (MSCs) and their nuclei. First, the imperative for study of live cells was demonstrated in studies showing changes in cell nucleus shape that were attributable to fixation per se. Hence, we compared live cell and nuclear volume and shape between groups of a model MSC line (C3H10T1/2) seeded at, or proliferated from 5,000 cells/cm2 to one of three target densities to achieve targeted development contexts. Cell volume was shown to be dependent on initial seeding density whereas nucleus shape was shown to depend on developmental context but not seeding density. Both smaller cell volumes and flatter nuclei were found to correlate with increased expression of markers for mesenchymal condensation as well as chondrogenic and osteogenic differentiation but a decreased expression of pre-condensation and adipogenic markers. Considering the data presented here, both seeding density and protocol significantly alter the morphology of mesenchymal stem cells even at very early stages of cell culture. Thus, these design parameters may play a critical role in the success of tissue engineering strategies seeking to recreate condensation events. However, a better understanding of how these changes in cell volume and nucleus shape relate to the differentiation of MSCs is important for prescribing precise seeding conditions necessary for the development of the desired tissue type. In a companion study (Part B, following), we address the effect of concomitant volume and shape changing stresses on spatiotemporal distribution of the cytoskeletal proteins actin and tubulin. Taken together, these studies bring us one step closer to our ultimate goal of elucidating the dynamics of nucleus and cell shape change as tissue templates grow (cell proliferation) and specialize (cell

  14. Stochastic Cell Fate Progression in Embryonic Stem Cells

    Science.gov (United States)

    Zou, Ling-Nan; Doyle, Adele; Jang, Sumin; Ramanathan, Sharad

    2013-03-01

    Studies on the directed differentiation of embryonic stem (ES) cells suggest that some early developmental decisions may be stochastic in nature. To identify the sources of this stochasticity, we analyzed the heterogeneous expression of key transcription factors in single ES cells as they adopt distinct germ layer fates. We find that under sufficiently stringent signaling conditions, the choice of lineage is unambiguous. ES cells flow into differentiated fates via diverging paths, defined by sequences of transitional states that exhibit characteristic co-expression of multiple transcription factors. These transitional states have distinct responses to morphogenic stimuli; by sequential exposure to multiple signaling conditions, ES cells are steered towards specific fates. However, the rate at which cells travel down a developmental path is stochastic: cells exposed to the same signaling condition for the same amount of time can populate different states along the same path. The heterogeneity of cell states seen in our experiments therefore does not reflect the stochastic selection of germ layer fates, but the stochastic rate of progression along a chosen developmental path. Supported in part by the Jane Coffin Childs Fund

  15. EMT and MET as paradigms for cell fate switching

    Institute of Scientific and Technical Information of China (English)

    Jiekai Chen; Qingkai Han; Duanqing Pei

    2012-01-01

    Cell fate determination is a major unsolved problem in cell and developmental biology,The discovery of reprogramming by pluripotent factors offers a rational system to investigate the molecular mechanisms associated with cell fate decisions.The idea that reprogramming of fibroblasts starts with a mesenchymal-epithelial transition (MET) suggests that the process is perhaps a reversal of epithelial to mesenchymal transition (EMT) found frequently during early embryogenesis,As such,we believe that investigations into MET-EMT may yield detailed molecular insights into cell fate decisions,not only for the switching between epithelial and mesenchymal cells,but also other cell types.

  16. Back and forth between cell fate specification and movement during vertebrate gastrulation.

    Science.gov (United States)

    Heisenberg, Carl-Philipp; Solnica-Krezel, Lilianna

    2008-08-01

    Animal body plan arises during gastrulation and organogenesis by the coordination of inductive events and cell movements. Several signaling pathways, such as BMP, FGF, Hedgehog, Nodal, and Wnt have well-recognized instructive roles in cell fate specification during vertebrate embryogenesis. Growing evidence indicates that BMP, Nodal, and FGF signaling also regulate cell movements, and that they do so through mechanisms distinct from those that specify cell fates. Moreover, pathways controlling cell movements can also indirectly influence cell fate specification by regulating dimensions and relative positions of interacting tissues. The current challenge is to delineate the molecular mechanisms via which the major signaling pathways regulate cell fate specification and movements, and how these two processes are coordinated to ensure normal development.

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

    Directory of Open Access Journals (Sweden)

    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

  18. The histone deacetylase SIRT6 controls embryonic stem cell fate via TET-mediated production of 5-hydroxymethylcytosine.

    Science.gov (United States)

    Etchegaray, Jean-Pierre; Chavez, Lukas; Huang, Yun; Ross, Kenneth N; Choi, Jiho; Martinez-Pastor, Barbara; Walsh, Ryan M; Sommer, Cesar A; Lienhard, Matthias; Gladden, Adrianne; Kugel, Sita; Silberman, Dafne M; Ramaswamy, Sridhar; Mostoslavsky, Gustavo; Hochedlinger, Konrad; Goren, Alon; Rao, Anjana; Mostoslavsky, Raul

    2015-05-01

    How embryonic stem cells (ESCs) commit to specific cell lineages and yield all cell types of a fully formed organism remains a major question. ESC differentiation is accompanied by large-scale histone and DNA modifications, but the relations between these epigenetic categories are not understood. Here we demonstrate the interplay between the histone deacetylase sirtuin 6 (SIRT6) and the ten-eleven translocation enzymes (TETs). SIRT6 targets acetylated histone H3 at Lys 9 and 56 (H3K9ac and H3K56ac), while TETs convert 5-methylcytosine into 5-hydroxymethylcytosine (5hmC). ESCs derived from Sirt6 knockout (S6KO) mice are skewed towards neuroectoderm development. This phenotype involves derepression of OCT4, SOX2 and NANOG, which causes an upregulation of TET-dependent production of 5hmC. Genome-wide analysis revealed neural genes marked with 5hmC in S6KO ESCs, thereby implicating TET enzymes in the neuroectoderm-skewed differentiation phenotype. We demonstrate that SIRT6 functions as a chromatin regulator safeguarding the balance between pluripotency and differentiation through Tet-mediated production of 5hmC.

  19. Retinoic Acid Receptors Control Spermatogonia Cell-Fate and Induce Expression of the SALL4A Transcription Factor.

    Directory of Open Access Journals (Sweden)

    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. 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

    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...

  1. Distinct and overlapping gene regulatory networks in BMP- and HDAC-controlled cell fate determination in the embryonic forebrain

    Directory of Open Access Journals (Sweden)

    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. Slit/Robo signaling regulates cell fate decisions in the intestinal stem cell lineage of Drosophila.

    Science.gov (United States)

    Biteau, Benoît; Jasper, Heinrich

    2014-06-26

    In order to maintain tissue homeostasis, cell fate decisions within stem cell lineages have to respond to the needs of the tissue. This coordination of lineage choices with regenerative demand remains poorly characterized. Here, we identify a signal from enteroendocrine cells (EEs) that controls lineage specification in the Drosophila intestine. We find that EEs secrete Slit, a ligand for the Robo2 receptor in intestinal stem cells (ISCs) that limits ISC commitment to the endocrine lineage, establishing negative feedback control of EE regeneration. Furthermore, we show that this lineage decision is made within ISCs and requires induction of the transcription factor Prospero in ISCs. Our work identifies a function for the conserved Slit/Robo pathway in the regulation of adult stem cells, establishing negative feedback control of ISC lineage specification as a critical strategy to preserve tissue homeostasis. Our results further amend the current understanding of cell fate commitment within the Drosophila ISC lineage.

  3. Slit/Robo Signaling Regulates Cell Fate Decisions in the Intestinal Stem Cell Lineage of Drosophila

    Directory of Open Access Journals (Sweden)

    Benoît Biteau

    2014-06-01

    Full Text Available In order to maintain tissue homeostasis, cell fate decisions within stem cell lineages have to respond to the needs of the tissue. This coordination of lineage choices with regenerative demand remains poorly characterized. Here, we identify a signal from enteroendocrine cells (EEs that controls lineage specification in the Drosophila intestine. We find that EEs secrete Slit, a ligand for the Robo2 receptor in intestinal stem cells (ISCs that limits ISC commitment to the endocrine lineage, establishing negative feedback control of EE regeneration. Furthermore, we show that this lineage decision is made within ISCs and requires induction of the transcription factor Prospero in ISCs. Our work identifies a function for the conserved Slit/Robo pathway in the regulation of adult stem cells, establishing negative feedback control of ISC lineage specification as a critical strategy to preserve tissue homeostasis. Our results further amend the current understanding of cell fate commitment within the Drosophila ISC lineage.

  4. 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.

  5. Overcoming CD4 Th1 Cell Fate Restrictions to Sustain Antiviral CD8 T Cells and Control Persistent Virus Infection.

    Science.gov (United States)

    Snell, Laura M; Osokine, Ivan; Yamada, Douglas H; De la Fuente, Justin Rafael; Elsaesser, Heidi J; Brooks, David G

    2016-09-20

    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.

  6. Cell fate patterning during C. elegans vulval development

    OpenAIRE

    Hill, Russell J.; Sternberg, Paul W.

    1993-01-01

    Precursor cells of the vulva of the C. elegans hermaphrodite choose between two vulval cell fates (1° and 2°) and a non-vulval epidermal fate (3°) in response to three intercellular signals. An inductive signal produced by the anchor cell induces the vulval precursors to assume the 1° and 2° vulval fates. This inductive signal is an EGF-like growth factor encoded by the gene lin-3. An inhibitory signal mediated by lin-15, and which may originate from the surrounding epidermis, prevents the vu...

  7. How the cell cycle impacts chromatin architecture and influences cell fate

    Directory of Open Access Journals (Sweden)

    Yiqin eMa

    2015-02-01

    Full Text Available Since the earliest observations of cells undergoing mitosis, it has been clear that there is an intimate relationship between the cell cycle and nuclear chromatin architecture. The nuclear envelope and chromatin undergo robust assembly and disassembly during the cell cycle, and transcriptional and post-transcriptional regulation of histone biogenesis and chromatin modification is controlled in a cell cycle-dependent manner. Chromatin binding proteins and chromatin modifications in turn influence the expression of critical cell cycle regulators, the accessibility of origins for DNA replication, DNA repair, and cell fate. In this review we aim to provide an integrated discussion of how the cell cycle machinery impacts nuclear architecture and vice-versa. We highlight recent advances in understanding cell cycle-dependent histone biogenesis and histone modification deposition, how cell cycle regulators control histone modifier activities, the contribution of chromatin modifications to origin firing for DNA replication, and newly identified roles for nucleoporins in regulating cell cycle gene expression, gene expression memory and differentiation. We close with a discussion of how cell cycle status may impact chromatin to influence cell fate decisions, under normal contexts of differentiation as well as in instances of cell fate re-programming.

  8. An illusion of control modulates the reluctance to tempt fate

    Directory of Open Access Journals (Sweden)

    Chloe L. Swirsky

    2011-10-01

    Full Text Available The tempting fate effect is that the probability of a fateful outcome is deemed higher following an action that ``tempts'' the outcome than in the absence of such an action. In this paper we evaluate the hypothesis that the effect is due to an illusion of control induced by a causal framing of the situation. Causal frames require that the action make a difference to an outcome and that the action precedes the outcome. If an illusion of control modulates the reluctance to tempt fate, then actions that make a difference to well-being and that occur prior to the outcome should tempt fate most strongly. In Experiments 1--3 we varied whether the action makes a difference and the temporal order of action and outcome. In Experiment 4 we tested whether an action can tempt fate if all outcomes are negative. The results of all four experiments supported our hypothesis that the tempting fate effect depends on a causal construal that gives rise to a false sense of control.

  9. Cell fate regulation governed by a repurposed bacterial histidine kinase.

    Directory of Open Access Journals (Sweden)

    W Seth Childers

    2014-10-01

    Full Text Available One of the simplest organisms to divide asymmetrically is the bacterium Caulobacter crescentus. The DivL pseudo-histidine kinase, positioned at one cell pole, regulates cell-fate by controlling the activation of the global transcription factor CtrA via an interaction with the response regulator (RR DivK. DivL uniquely contains a tyrosine at the histidine phosphorylation site, and can achieve these regulatory functions in vivo without kinase activity. Determination of the DivL crystal structure and biochemical analysis of wild-type and site-specific DivL mutants revealed that the DivL PAS domains regulate binding specificity for DivK∼P over DivK, which is modulated by an allosteric intramolecular interaction between adjacent domains. We discovered that DivL's catalytic domains have been repurposed as a phosphospecific RR input sensor, thereby reversing the flow of information observed in conventional histidine kinase (HK-RR systems and coupling a complex network of signaling proteins for cell-fate regulation.

  10. 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.

  11. EBI2 augments Tfh cell fate by promoting interaction with IL-2-quenching dendritic cells.

    Science.gov (United States)

    Li, Jianhua; Lu, Erick; Yi, Tangsheng; Cyster, Jason G

    2016-05-05

    T follicular helper (Tfh) cells are a subset of T cells carrying the CD4 antigen; they are important in supporting plasma cell and germinal centre responses. The initial induction of Tfh cell properties occurs within the first few days after activation by antigen recognition on dendritic cells, although how dendritic cells promote this cell-fate decision is not fully understood. Moreover, although Tfh cells are uniquely defined by expression of the follicle-homing receptor CXCR5 (refs 1, 2), the guidance receptor promoting the earlier localization of activated T cells at the interface of the B-cell follicle and T zone has been unclear. Here we show that the G-protein-coupled receptor EBI2 (GPR183) and its ligand 7α,25-dihydroxycholesterol mediate positioning of activated CD4 T cells at the interface of the follicle and T zone. In this location they interact with activated dendritic cells and are exposed to Tfh-cell-promoting inducible co-stimulator (ICOS) ligand. Interleukin-2 (IL-2) is a cytokine that has multiple influences on T-cell fate, including negative regulation of Tfh cell differentiation. We demonstrate that activated dendritic cells in the outer T zone further augment Tfh cell differentiation by producing membrane and soluble forms of CD25, the IL-2 receptor α-chain, and quenching T-cell-derived IL-2. Mice lacking EBI2 in T cells or CD25 in dendritic cells have reduced Tfh cells and mount defective T-cell-dependent plasma cell and germinal centre responses. These findings demonstrate that distinct niches within the lymphoid organ T zone support distinct cell fate decisions, and they establish a function for dendritic-cell-derived CD25 in controlling IL-2 availability and T-cell differentiation.

  12. Cell Fate Switch during In Vitro Plant Organogenesis

    Institute of Scientific and Technical Information of China (English)

    Xiang Yu Zhao; Ying Hua Su; Zhi Juan Cheng; Xian Sheng Zhang

    2008-01-01

    Plant mature cells have the capability to reverse their state of differenUation and produce new organs under cultured conditions. Two phases, dedifferentiation and redifferentiation, are commonly characterized during in vitro organogenesis.In these processes, cells undergo fate switch several times regulated by both extrinsic and intrinsic factors, which are associated with reentry to the cell cycle, the balance between euchromatin and heterochromatin, reprogramming of gene expression, and so forth. This short article reviews the advances in the mechanism of organ regeneration from plant somatic cells in molecular, genomic and epigenetic aspects, aiming to provide important information on the mechanism underlying cell fate switch during in vitro plant organogenesis.

  13. Regulation of monocyte cell fate by blood vessels mediated by Notch signalling.

    Science.gov (United States)

    Gamrekelashvili, Jaba; Giagnorio, Roberto; Jussofie, Jasmin; Soehnlein, Oliver; Duchene, Johan; Briseño, Carlos G; Ramasamy, Saravana K; Krishnasamy, Kashyap; Limbourg, Anne; Kapanadze, Tamar; Ishifune, Chieko; Hinkel, Rabea; Radtke, Freddy; Strobl, Lothar J; Zimber-Strobl, Ursula; Napp, L Christian; Bauersachs, Johann; Haller, Hermann; Yasutomo, Koji; Kupatt, Christian; Murphy, Kenneth M; Adams, Ralf H; Weber, Christian; Limbourg, Florian P

    2016-08-31

    A population of monocytes, known as Ly6C(lo) monocytes, patrol blood vessels by crawling along the vascular endothelium. Here we show that endothelial cells control their origin through Notch signalling. Using combinations of conditional genetic deletion strategies and cell-fate tracking experiments we show that Notch2 regulates conversion of Ly6C(hi) monocytes into Ly6C(lo) monocytes in vivo and in vitro, thereby regulating monocyte cell fate under steady-state conditions. This process is controlled by Notch ligand delta-like 1 (Dll1) expressed by a population of endothelial cells that constitute distinct vascular niches in the bone marrow and spleen in vivo, while culture on recombinant DLL1 induces monocyte conversion in vitro. Thus, blood vessels regulate monocyte conversion, a form of committed myeloid cell fate regulation.

  14. Positional cues specify and maintain aleurone cell fate in maize endosperm development.

    Science.gov (United States)

    Becraft, P W; Asuncion-Crabb, Y

    2000-09-01

    A genetic analysis of maize aleurone development was conducted. Cell lineage was examined by simultaneously marking cells with C1 for anthocyanin pigmentation in the aleurone and wx1 for amylose synthesis in the starchy endosperm. The aleurone and starchy endosperm share a common lineage throughout development indicating that positional cues specify aleurone fate. Mutants in dek1 block aleurone formation at an early stage and cause peripheral endosperm cells to develop as starchy endosperm. Revertant sectors of a transposon-induced dek1 allele showed that peripheral endosperm cells remain competent to differentiate as aleurone cells until late in development. Ds-induced chromosome breakage was used to generate Dek1 loss-of-function sectors. Events occurring until late development caused aleurone cells to switch fate to starchy endosperm indicating that cell fate is not fixed. Thus, positional cues are required to specify and maintain aleurone fate and Dek1 function is required to respond to these cues. An analysis of additional mutants that disrupt aleurone differentiation suggests a hierarchy of gene functions to specify aleurone cell fate and then control aleurone differentiation. These mutants disrupt aleurone differentiation in reproducible patterns suggesting a relationship to endosperm pattern formation.

  15. Cell fate determination by ubiquitin-dependent regulation of translation

    Science.gov (United States)

    Werner, Achim; Iwasaki, Shintaro; McGourty, Colleen; Medina-Ruiz, Sofia; Teerikorpi, Nia; Fedrigo, Indro; Ingolia, Nicholas T.; Rape, Michael

    2015-01-01

    Metazoan development depends on accurate execution of differentiation programs that allow pluripotent stem cells to adopt specific fates 1. Differentiation requires changes to chromatin architecture and transcriptional networks, yet whether other regulatory events support cell fate determination is less well understood. Here, we have identified the vertebrate-specific ubiquitin ligase CUL3KBTBD8 as an essential regulator of neural crest specification. CUL3KBTBD8 monoubiquitylates NOLC1 and its paralog TCOF1, whose mutation underlies the neurocristopathy Treacher Collins Syndrome 2,3. Ubiquitylation drives formation of a TCOF1-NOLC1 platform that connects RNA polymerase I with ribosome modification enzymes and remodels the translational program of differentiating cells in favor of neural crest specification. We conclude that ubiquitin-dependent regulation of translation is an important feature of cell fate determination. PMID:26399832

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

    DEFF Research Database (Denmark)

    van Impel, Andreas; Zhao, Zhonghua; Hermkens, Dorien M A;

    2014-01-01

    . Murine Prox1-null embryos lack lymphatic structures, and sustained expression of Prox1 is indispensable for the maintenance of lymphatic cell fate even at adult stages, highlighting the unique importance of this gene for the lymphatic lineage. Whether this pre-eminent role of Prox1 within the lymphatic...... vasculature is conserved in other vertebrate classes has remained unresolved, mainly owing to the lack of availability of loss-of-function mutants. Here, we re-examine the role of Prox1a in zebrafish lymphangiogenesis. First, using a transgenic reporter line, we show that prox1a is initially expressed...... that the functionally related transcription factors Coup-TFII and Sox18 are also dispensable for lymphangiogenesis. Together, these findings suggest that lymphatic commitment in zebrafish and mice is controlled in fundamentally different ways....

  17. 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 Wnt/beta-ca

  18. Stem cell decisions: a twist of fate or a niche market?

    Science.gov (United States)

    Januschke, Jens; Näthke, Inke

    2014-10-01

    Establishing and maintaining cell fate in the right place at the right time is a key requirement for normal tissue maintenance. Stem cells are at the core of this process. Understanding how stem cells balance self-renewal and production of differentiating cells is key for understanding the defects that underpin many diseases. Both, external cues from the environment and cell intrinsic mechanisms can control the outcome of stem cell division. The role of the orientation of stem cell division has emerged as an important mechanism for specifying cell fate decisions. Although, the alignment of cell divisions can dependent on spatial cues from the environment, maintaining stemness is not always linked to positioning of stem cells in a particular microenvironment or `niche'. Alternate mechanisms that could contribute to cellular memory include differential segregation of centrosomes in asymmetrically dividing cells.

  19. Surface position, not signaling from surrounding maternal tissues, specifies aleurone epidermal cell fate in maize.

    Science.gov (United States)

    Gruis, Darren Fred; Guo, Hena; Selinger, David; Tian, Qing; Olsen, Odd-Arne

    2006-07-01

    Maize (Zea mays) endosperm consists of an epidermal-like surface layer of aleurone cells, an underlying body of starchy endosperm cells, and a basal layer of transfer cells. To determine whether surrounding maternal tissues perform a role in specifying endosperm cell fates, a maize endosperm organ culture technique was established whereby the developing endosperm is completely removed from surrounding maternal tissues. Using cell type-specific fluorescence markers, we show that aleurone cell fate specification occurs exclusively in response to surface position and does not require specific, continued maternal signal input. The starchy endosperm and aleurone cell fates are freely interchangeable throughout the lifespan of the endosperm, with internalized aleurone cells converting to starchy endosperm cells and with starchy endosperm cells that become positioned at the surface converting to aleurone cells. In contrast to aleurone and starchy endosperm cells, transfer cells fail to develop in in vitro-grown endosperm, supporting earlier indications that maternal tissue interaction is required to fully differentiate this cell type. Several parameters confirm that the maize endosperm organ cultures described herein retain the main developmental features of in planta endosperm, including fidelity of aleurone mutant phenotypes, temporal and spatial control of cell type-specific fluorescent markers, specificity of cell type transcripts, and control of mitotic cell divisions.

  20. 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.

  1. Generation of bivalent chromatin domains during cell fate decisions

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    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.

  2. 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.

  3. Mitophagy-driven mitochondrial rejuvenation regulates stem cell fate

    Science.gov (United States)

    Vazquez-Martin, Alejandro; Van den Haute, Chris; Cufí, Sílvia; Corominas-Faja, Bruna; Cuyàs, Elisabet; Lopez-Bonet, Eugeni; Rodriguez-Gallego, Esther; Fernández-Arroyo, Salvador; Joven, Jorge; Baekelandt, Veerle; Menendez, Javier A.

    2016-01-01

    Our understanding on how selective mitochondrial autophagy, or mitophagy, can sustain the archetypal properties of stem cells is incomplete. PTEN-induced putative kinase 1 (PINK1) plays a key role in the maintenance of mitochondrial morphology and function and in the selective degradation of damaged mitochondria by mitophagy. Here, using embryonic fibroblasts from PINK1 gene-knockout (KO) mice, we evaluated whether mitophagy is a causal mechanism for the control of cell-fate plasticity and maintenance of pluripotency. Loss of PINK1-dependent mitophagy was sufficient to dramatically decrease the speed and efficiency of induced pluripotent stem cell (iPSC) reprogramming. Mitophagy-deficient iPSC colonies, which were characterized by a mixture of mature and immature mitochondria, seemed unstable, with a strong tendency to spontaneously differentiate and form heterogeneous populations of cells. Although mitophagy-deficient iPSC colonies normally expressed pluripotent markers, functional monitoring of cellular bioenergetics revealed an attenuated glycolysis in mitophagy-deficient iPSC cells. Targeted metabolomics showed a notable alteration in numerous glycolysis- and TCA-related metabolites in mitophagy-deficient iPSC cells, including a significant decrease in the intracellular levels of α-ketoglutarate -a key suppressor of the differentiation path in stem cells. Mitophagy-deficient iPSC colonies exhibited a notably reduced teratoma-initiating capacity, but fully retained their pluripotency and multi-germ layer differentiation capacity in vivo. PINK1-dependent mitophagy pathway is an important mitochondrial switch that determines the efficiency and quality of somatic reprogramming. Mitophagy-driven mitochondrial rejuvenation might contribute to the ability of iPSCs to suppress differentiation by directing bioenergetic transition and metabolome remodeling traits. These findings provide new insights into how mitophagy might influence the stem cell decisions to retain

  4. Neural Induction, Neural Fate Stabilization, and Neural Stem Cells

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    Sally A. Moody

    2002-01-01

    Full Text Available The promise of stem cell therapy is expected to greatly benefit the treatment of neurodegenerative diseases. An underlying biological reason for the progressive functional losses associated with these diseases is the extremely low natural rate of self-repair in the nervous system. Although the mature CNS harbors a limited number of self-renewing stem cells, these make a significant contribution to only a few areas of brain. Therefore, it is particularly important to understand how to manipulate embryonic stem cells and adult neural stem cells so their descendants can repopulate and functionally repair damaged brain regions. A large knowledge base has been gathered about the normal processes of neural development. The time has come for this information to be applied to the problems of obtaining sufficient, neurally committed stem cells for clinical use. In this article we review the process of neural induction, by which the embryonic ectodermal cells are directed to form the neural plate, and the process of neural�fate stabilization, by which neural plate cells expand in number and consolidate their neural fate. We will present the current knowledge of the transcription factors and signaling molecules that are known to be involved in these processes. We will discuss how these factors may be relevant to manipulating embryonic stem cells to express a neural fate and to produce large numbers of neurally committed, yet undifferentiated, stem cells for transplantation therapies.

  5. Msx2 in ameloblast cell fate and activity

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    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.

  6. Fate and degradation of petroleum hydrocarbons in stormwater bioretention cells

    Science.gov (United States)

    LeFevre, Gregory Hallett

    This dissertation describes the investigation of the fate of hydrocarbons in stormwater bioretention areas and those mechanisms that affect hydrocarbon fate in such systems. Seventy-five samples from 58 bioretention areas were collected and analyzed to measure total petroleum hydrocarbon (TPH) residual and biodegradation functional genes. TPH residual in bioretention areas was greater than background sites but low overall (biodegradation. Field soils were capable of mineralizing naphthalene, a polycyclic aromatic hydrocarbon (PAH) when incubated in the laboratory. In an additional laboratory investigation, a column study was initiated to comprehensively determine naphthalene fate in a simulated bioretention cell using a 14C-labeled tracer. Sorption to soil was the greatest sink of naphthalene in the columns, although biodegradation and vegetative uptake were also important loss mechanisms. Little leaching occurred following the first flush, and volatilization was insignificant. Significant enrichment of naphthalene degrading bacteria occurred over the course of the experiment as a result of naphthalene exposure. This was evident from enhanced naphthalene biodegradation kinetics (measured via batch tests), significant increases in naphthalene dioxygenase gene quantities, and a significant correlation observed between naphthalene residual and biodegradation functional genes. Vegetated columns outperformed the unplanted control column in terms of total naphthalene removal and biodegradation kinetics. As a result of these experiments, a final study focused on why planted systems outperform unplanted systems was conducted. Plant root exudates were harvested from hydroponic setups for three types of plants. Additionally, a solution of artificial root exudates (AREs) as prepared. Exudates were digested using soil bacteria to create metabolized exudates. Raw and metabolized exudates were characterized for dissolved organic carbon, specific UV absorbance, spectral slope

  7. Bi-modal distribution of the second messenger c-di-GMP controls cell fate and asymmetry during the caulobacter cell cycle.

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    Sören Abel

    Full Text Available Many bacteria mediate important life-style decisions by varying levels of the second messenger c-di-GMP. Behavioral transitions result from the coordination of complex cellular processes such as motility, surface adherence or the production of virulence factors and toxins. While the regulatory mechanisms responsible for these processes have been elucidated in some cases, the global pleiotropic effects of c-di-GMP are poorly understood, primarily because c-di-GMP networks are inherently complex in most bacteria. Moreover, the quantitative relationships between cellular c-di-GMP levels and c-di-GMP dependent phenotypes are largely unknown. Here, we dissect the c-di-GMP network of Caulobacter crescentus to establish a global and quantitative view of c-di-GMP dependent processes in this organism. A genetic approach that gradually reduced the number of diguanylate cyclases identified novel c-di-GMP dependent cellular processes and unraveled c-di-GMP as an essential component of C. crescentus cell polarity and its bimodal life cycle. By varying cellular c-di-GMP concentrations, we determined dose response curves for individual c-di-GMP-dependent processes. Relating these values to c-di-GMP levels modeled for single cells progressing through the cell cycle sets a quantitative frame for the successive activation of c-di-GMP dependent processes during the C. crescentus life cycle. By reconstructing a simplified c-di-GMP network in a strain devoid of c-di-GMP we defined the minimal requirements for the oscillation of c-di-GMP levels during the C. crescentus cell cycle. Finally, we show that although all c-di-GMP dependent cellular processes were qualitatively restored by artificially adjusting c-di-GMP levels with a heterologous diguanylate cyclase, much higher levels of the second messenger are required under these conditions as compared to the contribution of homologous c-di-GMP metabolizing enzymes. These experiments suggest that a common c-di-GMP pool

  8. Self-Organizing Global Gene Expression Regulated through Criticality: Mechanism of the Cell-Fate Change

    Science.gov (United States)

    Tsuchiya, Masa; Giuliani, Alessandro; Hashimoto, Midori; Erenpreisa, Jekaterina; Yoshikawa, Kenichi

    2016-01-01

    Background A fundamental issue in bioscience is to understand the mechanism that underlies the dynamic control of genome-wide expression through the complex temporal-spatial self-organization of the genome to regulate the change in cell fate. We address this issue by elucidating a physically motivated mechanism of self-organization. Principal Findings Building upon transcriptome experimental data for seven distinct cell fates, including early embryonic development, we demonstrate that self-organized criticality (SOC) plays an essential role in the dynamic control of global gene expression regulation at both the population and single-cell levels. The novel findings are as follows: i) Mechanism of cell-fate changes: A sandpile-type critical transition self-organizes overall expression into a few transcription response domains (critical states). A cell-fate change occurs by means of a dissipative pulse-like global perturbation in self-organization through the erasure of initial-state critical behaviors (criticality). Most notably, the reprogramming of early embryo cells destroys the zygote SOC control to initiate self-organization in the new embryonal genome, which passes through a stochastic overall expression pattern. ii) Mechanism of perturbation of SOC controls: Global perturbations in self-organization involve the temporal regulation of critical states. Quantitative evaluation of this perturbation in terminal cell fates reveals that dynamic interactions between critical states determine the critical-state coherent regulation. The occurrence of a temporal change in criticality perturbs this between-states interaction, which directly affects the entire genomic system. Surprisingly, a sub-critical state, corresponding to an ensemble of genes that shows only marginal changes in expression and consequently are considered to be devoid of any interest, plays an essential role in generating a global perturbation in self-organization directed toward the cell-fate change

  9. Delayed transition to new cell fates during cellular reprogramming.

    Science.gov (United States)

    Cheng, Xianrui; Lyons, Deirdre C; Socolar, Joshua E S; McClay, David R

    2014-07-15

    In many embryos specification toward one cell fate can be diverted to a different cell fate through a reprogramming process. Understanding how that process works will reveal insights into the developmental regulatory logic that emerged from evolution. In the sea urchin embryo, cells at gastrulation were found to reprogram and replace missing cell types after surgical dissections of the embryo. Non-skeletogenic mesoderm (NSM) cells reprogrammed to replace missing skeletogenic mesoderm cells and animal caps reprogrammed to replace all endomesoderm. In both cases evidence of reprogramming onset was first observed at the early gastrula stage, even if the cells to be replaced were removed earlier in development. Once started however, the reprogramming occurred with compressed gene expression dynamics. The NSM did not require early contact with the skeletogenic cells to reprogram, but the animal cap cells gained the ability to reprogram early in gastrulation only after extended contact with the vegetal halves prior to that time. If the entire vegetal half was removed at early gastrula, the animal caps reprogrammed and replaced the vegetal half endomesoderm. If the animal caps carried morpholinos to either hox11/13b or foxA (endomesoderm specification genes), the isolated animal caps failed to reprogram. Together these data reveal that the emergence of a reprogramming capability occurs at early gastrulation in the sea urchin embryo and requires activation of early specification components of the target tissues.

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

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    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.

  11. Fate restriction and multipotency in retinal stem cells.

    Science.gov (United States)

    Centanin, Lázaro; Hoeckendorf, Burkhard; Wittbrodt, Joachim

    2011-12-02

    Stem cells have the capacity to both self-renew and generate postmitotic cells. Long-term tracking of individual clones in their natural environment constitutes the ultimate way to validate postembryonic stem cells. We identify retinal stem cells (RSCs) using the spatiotemporal organization of the fish retina and follow the complete offspring of a single cell during the postnatal life. RSCs generate two tissues of the adult fish retina, the neural retina (NR) and the retinal-pigmented epithelium (RPE). Despite their common embryonic origin and tight coordination during continuous organ growth, we prove that NR and RPE are maintained by dedicated RSCs that contribute in a fate-restricted manner to either one or the other tissue. We show that in the NR, RSCs are multipotent and generate all neuron types and glia. The clonal origin of these different cell types from a multipotent NSC has far-reaching implications for cell type and tissue homeostasis.

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

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    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.

  13. Involvement of C2H2 zinc finger proteins in the regulation of epidermal cell fate determination in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    An Yan; Minjie Wu; Yongqin Zhao; Aidong Zhang; Bohan Liu; John Schiefelbein; Yinbo Gan

    2014-01-01

    Cell fate determination is a basic developmental process during the growth of multicellular organisms. Trichomes and root hairs of Arabidopsis are both readily accessible structures originating from the epidermal cells of the aerial tissues and roots respectively, and they serve as excellent models for understanding the molecular mecha-nisms controlling cell fate determination and cell morphogen-esis. The regulation of trichome and root hair formation is a complex program that consists of the integration of hormonal signals with a large number of transcriptional factors, including MYB and bHLH transcriptional factors. Studies during recent years have uncovered an important role of C2H2 type zinc finger proteins in the regulation of epidermal cell fate determination. Here in this minireview we briefly summarize the involvement of C2H2 zinc finger proteins in the control of trichome and root hair formation in Arabidopsis.

  14. Intracellular Events and Cell Fate in Filovirus Infection

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    Elena Ryabchikova

    2011-08-01

    Full Text Available Marburg and Ebola viruses cause a severe hemorrhagic disease in humans with high fatality rates. Early target cells of filoviruses are monocytes, macrophages, and dendritic cells. The infection spreads to the liver, spleen and later other organs by blood and lymph flow. A hallmark of filovirus infection is the depletion of non-infected lymphocytes; however, the molecular mechanisms leading to the observed bystander lymphocyte apoptosis are poorly understood. Also, there is limited knowledge about the fate of infected cells in filovirus disease. In this review we will explore what is known about the intracellular events leading to virus amplification and cell damage in filovirus infection. Furthermore, we will discuss how cellular dysfunction and cell death may correlate with disease pathogenesis.

  15. Origin and fate of the regenerating cells of the kidney.

    Science.gov (United States)

    Eymael, Jennifer; Smeets, Bart

    2016-11-05

    The kidney has the capacity to regenerate itself provided that the damage is limited and the structure of the kidney remains intact. Nevertheless, in disease conditions this potential may be compromised, leading to progression to chronic kidney disease. For development of new therapeutic strategies it is a prerequisite to understand the origin and regulation of the kidney regenerating cells and the processes that underlie maladaptive repair. Because of the complexity of the kidney consisting of a high number of different cell types, it is a complex task to unravel the origin and fate of cells responsible for regeneration. This review summarises the recent and most important advances in identifying regenerating cell populations of the kidney, and highlights the existing controversies.

  16. Spatially patterned matrix elasticity directs stem cell fate

    Science.gov (United States)

    Yang, Chun; DelRio, Frank W.; Ma, Hao; Killaars, Anouk R.; Basta, Lena P.; Kyburz, Kyle A.; Anseth, Kristi S.

    2016-08-01

    There is a growing appreciation for the functional role of matrix mechanics in regulating stem cell self-renewal and differentiation processes. However, it is largely unknown how subcellular, spatial mechanical variations in the local extracellular environment mediate intracellular signal transduction and direct cell fate. Here, the effect of spatial distribution, magnitude, and organization of subcellular matrix mechanical properties on human mesenchymal stem cell (hMSCs) function was investigated. Exploiting a photodegradation reaction, a hydrogel cell culture substrate was fabricated with regions of spatially varied and distinct mechanical properties, which were subsequently mapped and quantified by atomic force microscopy (AFM). The variations in the underlying matrix mechanics were found to regulate cellular adhesion and transcriptional events. Highly spread, elongated morphologies and higher Yes-associated protein (YAP) activation were observed in hMSCs seeded on hydrogels with higher concentrations of stiff regions in a dose-dependent manner. However, when the spatial organization of the mechanically stiff regions was altered from a regular to randomized pattern, lower levels of YAP activation with smaller and more rounded cell morphologies were induced in hMSCs. We infer from these results that irregular, disorganized variations in matrix mechanics, compared with regular patterns, appear to disrupt actin organization, and lead to different cell fates; this was verified by observations of lower alkaline phosphatase (ALP) activity and higher expression of CD105, a stem cell marker, in hMSCs in random versus regular patterns of mechanical properties. Collectively, this material platform has allowed innovative experiments to elucidate a novel spatial mechanical dosing mechanism that correlates to both the magnitude and organization of spatial stiffness.

  17. Engineering Cell Fate for Tissue Regeneration by In Vivo Transdifferentiation.

    Science.gov (United States)

    de Lázaro, I; Kostarelos, K

    2016-02-01

    Changes in cell identity occur in adult mammalian organisms but are rare and often linked to disease. Research in the last few decades has thrown light on how to manipulate cell fate, but the conversion of a particular cell type into another within a living organism (also termed in vivo transdifferentiation) has only been recently achieved in a limited number of tissues. Although the therapeutic promise of this strategy for tissue regeneration and repair is exciting, important efficacy and safety concerns will need to be addressed before it becomes a reality in the clinical practice. Here, we review the most relevant in vivo transdifferentiation studies in adult mammalian animal models, offering a critical assessment of this potentially powerful strategy for regenerative medicine.

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

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    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.

  19. 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.

  20. GATA3 induces human T-cell commitment by restraining Notch activity and repressing NK-cell fate

    Science.gov (United States)

    Van de Walle, Inge; Dolens, Anne-Catherine; Durinck, Kaat; De Mulder, Katrien; Van Loocke, Wouter; Damle, Sagar; Waegemans, Els; De Medts, Jelle; Velghe, Imke; De Smedt, Magda; Vandekerckhove, Bart; Kerre, Tessa; Plum, Jean; Leclercq, Georges; Rothenberg, Ellen V.; Van Vlierberghe, Pieter; Speleman, Frank; Taghon, Tom

    2016-01-01

    The gradual reprogramming of haematopoietic precursors into the T-cell fate is characterized by at least two sequential developmental stages. Following Notch1-dependent T-cell lineage specification during which the first T-cell lineage genes are expressed and myeloid and dendritic cell potential is lost, T-cell specific transcription factors subsequently induce T-cell commitment by repressing residual natural killer (NK)-cell potential. How these processes are regulated in human is poorly understood, especially since efficient T-cell lineage commitment requires a reduction in Notch signalling activity following T-cell specification. Here, we show that GATA3, in contrast to TCF1, controls human T-cell lineage commitment through direct regulation of three distinct processes: repression of NK-cell fate, upregulation of T-cell lineage genes to promote further differentiation and restraint of Notch activity. Repression of the Notch1 target gene DTX1 hereby is essential to prevent NK-cell differentiation. Thus, GATA3-mediated positive and negative feedback mechanisms control human T-cell lineage commitment. PMID:27048872

  1. Power-Law Modeling of Cancer Cell Fates Driven by Signaling Data to Reveal Drug Effects

    Science.gov (United States)

    Zhang, Fan; Wu, Min; Kwoh, Chee Keong; Zheng, Jie

    2016-01-01

    Extracellular signals are captured and transmitted by signaling proteins inside a cell. An important type of cellular responses to the signals is the cell fate decision, e.g., apoptosis. However, the underlying mechanisms of cell fate regulation are still unclear, thus comprehensive and detailed kinetic models are not yet available. Alternatively, data-driven models are promising to bridge signaling data with the phenotypic measurements of cell fates. The traditional linear model for data-driven modeling of signaling pathways has its limitations because it assumes that the a cell fate is proportional to the activities of signaling proteins, which is unlikely in the complex biological systems. Therefore, we propose a power-law model to relate the activities of all the measured signaling proteins to the probabilities of cell fates. In our experiments, we compared our nonlinear power-law model with the linear model on three cancer datasets with phosphoproteomics and cell fate measurements, which demonstrated that the nonlinear model has superior performance on cell fates prediction. By in silico simulation of virtual protein knock-down, the proposed model is able to reveal drug effects which can complement traditional approaches such as binding affinity analysis. Moreover, our model is able to capture cell line specific information to distinguish one cell line from another in cell fate prediction. Our results show that the power-law data-driven model is able to perform better in cell fate prediction and provide more insights into the signaling pathways for cancer cell fates than the linear model. PMID:27764199

  2. 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.

  3. Oncogene-Induced Changes in Mammary Cell Fate and EMT in Breast Tumorigenesis

    Science.gov (United States)

    2015-04-01

    Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Basal-like/ triple negative breast cancers (TNBCs) are characterized by...24 4 1. INTRODUCTION: Basal-like/ triple negative breast cancers (TNBCs) are characterized by distinctive morphologic, genetic, and clinical features...with tumor initiation and cell fate markers. 2. KEYWORDS: IGF1R, triple - negative breast cancer, luminal, myoepithelial, cell fate 3. ACCOMPLISHMENTS

  4. p47phox Directs Murine Macrophage Cell Fate Decisions

    Science.gov (United States)

    Yi, Liang; Liu, Qi; Orandle, Marlene S.; Sadiq-Ali, Sara; Koontz, Sherry M.; Choi, Uimook; Torres-Velez, Fernando J.; Jackson, Sharon H.

    2012-01-01

    Macrophage differentiation and function are pivotal for cell survival from infection and involve the processing of microenvironmental signals that determine macrophage cell fate decisions to establish appropriate inflammatory balance. NADPH oxidase 2 (Nox2)–deficient chronic granulomatous disease (CGD) mice that lack the gp91phox (gp91phox−/−) catalytic subunit show high mortality rates compared with wild-type mice when challenged by infection with Listeria monocytogenes (Lm), whereas p47phox-deficient (p47phox−/−) CGD mice show survival rates that are similar to those of wild-type mice. We demonstrate that such survival results from a skewed macrophage differentiation program in p47phox−/− mice that favors the production of higher levels of alternatively activated macrophages (AAMacs) compared with levels of either wild-type or gp91phox−/− mice. Furthermore, the adoptive transfer of AAMacs from p47phox−/− mice can rescue gp91phox−/− mice during primary Lm infection. Key features of the protective function provided by p47phox−/− AAMacs against Lm infection are enhanced production of IL-1α and killing of Lm. Molecular analysis of this process indicates that p47phox−/− macrophages are hyperresponsive to IL-4 and show higher Stat6 phosphorylation levels and signaling coupled to downstream activation of AAMac transcripts in response to IL-4 stimulation. Notably, restoring p47phox protein expression levels reverts the p47phox-dependent AAMac phenotype. Our results indicate that p47phox is a previously unrecognized regulator for IL-4 signaling pathways that are important for macrophage cell fate choice. PMID:22222227

  5. Pax6- and Six3-mediated induction of lens cell fate in mouse and human ES cells.

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    Raymond M Anchan

    Full Text Available Embryonic stem (ES cells provide a potentially useful in vitro model for the study of in vivo tissue differentiation. We used mouse and human ES cells to investigate whether the lens regulatory genes Pax6 and Six3 could induce lens cell fate in vitro. To help assess the onset of lens differentiation, we derived a new mES cell line (Pax6-GFP mES that expresses a GFP reporter under the control of the Pax6 P0 promoter and lens ectoderm enhancer. Pax6 or Six3 expression vectors were introduced into mES or hES cells by transfection or lentiviral infection and the differentiating ES cells analyzed for lens marker expression. Transfection of mES cells with Pax6 or Six3 but not with other genes induced the expression of lens cell markers and up-regulated GFP reporter expression in Pax6-GFP mES cells by 3 days post-transfection. By 7 days post-transfection, mES cell cultures exhibited a>10-fold increase over controls in the number of colonies expressing γA-crystallin, a lens fiber cell differentiation marker. RT-PCR and immunostaining revealed induction of additional lens epithelial or fiber cell differentiation markers including Foxe3, Prox1, α- and β-crystallins, and Tdrd7. Moreover, γA-crystallin- or Prox1-expressing lentoid bodies formed by 30 days in culture. In hES cells, Pax6 or Six3 lentiviral vectors also induced lens marker expression. mES cells that express lens markers reside close to but are distinct from the Pax6 or Six3 transduced cells, suggesting that the latter induce nearby undifferentiated ES cells to adopt a lens fate by non-cell autonomous mechanisms. In sum, we describe a novel mES cell GFP reporter line that is useful for monitoring induction of lens fate, and demonstrate that Pax6 or Six3 is sufficient to induce ES cells to adopt a lens fate, potentially via non-cell autonomous mechanisms. These findings should facilitate investigations of lens development.

  6. The C. elegans LIM homeobox gene lin-11 specifies multiple cell fates during vulval development.

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    Gupta, Bhagwati P; Wang, Minqin; Sternberg, Paul W

    2003-06-01

    LIM homeobox family members regulate a variety of cell fate choices during animal development. In C. elegans, mutations in the LIM homeobox gene lin-11 have previously been shown to alter the cell division pattern of a subset of the 2 degrees lineage vulval cells. We demonstrate multiple functions of lin-11 during vulval development. We examined the fate of vulval cells in lin-11 mutant animals using five cellular markers and found that lin-11 is necessary for the patterning of both 1 degrees and 2 degrees lineage cells. In the absence of lin-11 function, vulval cells fail to acquire correct identity and inappropriately fuse with each other. The expression pattern of lin-11 reveals dynamic changes during development. Using a temporally controlled overexpression system, we show that lin-11 is initially required in vulval cells for establishing the correct invagination pattern. This process involves asymmetric expression of lin-11 in the 2 degrees lineage cells. Using a conditional RNAi approach, we show that lin-11 regulates vulval morphogenesis. Finally, we show that LDB-1, a NLI/Ldb1/CLIM2 family member, interacts physically with LIN-11, and is necessary for vulval morphogenesis. Together, these findings demonstrate that temporal regulation of lin-11 is crucial for the wild-type vulval patterning.

  7. The control of axillary meristem fate in the maize ramosa pathway.

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    Gallavotti, Andrea; Long, Jeff A; Stanfield, Sharon; Yang, Xiang; Jackson, David; Vollbrecht, Erik; Schmidt, Robert J

    2010-09-01

    Plant axillary meristems are composed of highly organized, self-renewing stem cells that produce indeterminate branches or terminate in differentiated structures, such as the flowers. These opposite fates, dictated by both genetic and environmental factors, determine interspecific differences in the architecture of plants. The Cys(2)-His(2) zinc-finger transcription factor RAMOSA1 (RA1) regulates the fate of most axillary meristems during the early development of maize inflorescences, the tassel and the ear, and has been implicated in the evolution of grass architecture. Mutations in RA1 or any other known members of the ramosa pathway, RAMOSA2 and RAMOSA3, generate highly branched inflorescences. Here, we report a genetic screen for the enhancement of maize inflorescence branching and the discovery of a new regulator of meristem fate: the RAMOSA1 ENHANCER LOCUS2 (REL2) gene. rel2 mutants dramatically increase the formation of long branches in ears of both ra1 and ra2 mutants. REL2 encodes a transcriptional co-repressor similar to the TOPLESS protein of Arabidopsis, which is known to maintain apical-basal polarity during embryogenesis. REL2 is capable of rescuing the embryonic defects of the Arabidopsis topless-1 mutant, suggesting that REL2 also functions as a transcriptional co-repressor throughout development. We show by genetic and molecular analyses that REL2 physically interacts with RA1, indicating that the REL2/RA1 transcriptional repressor complex antagonizes the formation of indeterminate branches during maize inflorescence development. Our results reveal a novel mechanism for the control of meristem fate and the architecture of plants.

  8. The WEREWOLF MYB protein directly regulates CAPRICE transcription during cell fate specification in the Arabidopsis root epidermis.

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    Ryu, Kook Hui; Kang, Yeon Hee; Park, Young-hwan; Hwang, Ildoo; Schiefelbein, John; Lee, Myeong Min

    2005-11-01

    The Arabidopsis root epidermis is composed of two types of cells, hair cells and non-hair cells, and their fate is determined in a position-dependent manner. WEREWOLF (WER), a R2R3 MYB protein, has been shown genetically to function as a master regulator to control both of the epidermal cell fates. To directly test the proposed role of WER in this system, we examined its subcellular localization and defined its transcriptional activation properties. We show that a WER-GFP fusion protein is functional and accumulates in the nucleus of the N-position cells in the Arabidopsis root epidermis, as expected for a transcriptional regulator. We also find that a modified WER protein with a strong activation domain (WER-VP16) promotes the formation of both epidermal cell types, supporting the view that WER specifies both cell fates. In addition, we used the glucocorticoid receptor (GR) inducible system to show that CPC transcription is regulated directly by WER. Using EMSA, we found two WER-binding sites (WBSs; WBSI and WBSII) in the CPC promoter. WER-WBSI binding was confirmed in vivo using the yeast one-hybrid assay. Binding between the WER protein and both WBSs (WBSI and WBSII), and the importance of the two WBSs in CPC promoter activity were confirmed in Arabidopsis. These results provide experimental support for the proposed role of WER as an activator of gene transcription during the specification of both epidermal cell fates.

  9. Mechanical memory and dosing influence stem cell fate

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    Yang, Chun; Tibbitt, Mark W.; Basta, Lena; Anseth, Kristi S.

    2014-06-01

    We investigated whether stem cells remember past physical signals and whether these can be exploited to dose cells mechanically. We found that the activation of the Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding domain (TAZ) as well as the pre-osteogenic transcription factor RUNX2 in human mesenchymal stem cells (hMSCs) cultured on soft poly(ethylene glycol) (PEG) hydrogels (Young’s modulus E ~ 2 kPa) depended on previous culture time on stiff tissue culture polystyrene (TCPS; E ~ 3 GPa). In addition, mechanical dosing of hMSCs cultured on initially stiff (E ~ 10 kPa) and then soft (E ~ 2 kPa) phototunable PEG hydrogels resulted in either reversible or—above a threshold mechanical dose—irreversible activation of YAP/TAZ and RUNX2. We also found that increased mechanical dosing on supraphysiologically stiff TCPS biases hMSCs towards osteogenic differentiation. We conclude that stem cells possess mechanical memory—with YAP/TAZ acting as an intracellular mechanical rheostat—that stores information from past physical environments and influences the cells’ fate.

  10. Regulation of cell fate and meristem maintenance in Arabidopsis root development

    NARCIS (Netherlands)

    ten Hove, C.A.

    2010-01-01

    Asymmetric cell division is an essential and universal mechanism for generating diversity and pattern in multicellular organisms. Divisions generating daughter cells different in size, shape, identity and function are fundamental to many developmental processes including fate specification, tissue p

  11. 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

  12. Ablation of coactivator Med1 switches the cell fate of dental epithelia to that generating hair.

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    Keigo Yoshizaki

    Full Text Available Cell fates are determined by specific transcriptional programs. Here we provide evidence that the transcriptional coactivator, Mediator 1 (Med1, is essential for the cell fate determination of ectodermal epithelia. Conditional deletion of Med1 in vivo converted dental epithelia into epidermal epithelia, causing defects in enamel organ development while promoting hair formation in the incisors. We identified multiple processes by which hairs are generated in Med1 deficient incisors: 1 dental epithelial stem cells lacking Med 1 fail to commit to the dental lineage, 2 Sox2-expressing stem cells extend into the differentiation zone and remain multi-potent due to reduced Notch1 signaling, and 3 epidermal fate is induced by calcium as demonstrated in dental epithelial cell cultures. These results demonstrate that Med1 is a master regulator in adult stem cells to govern epithelial cell fate.

  13. 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.

  14. Ectopic expression of Cvh (Chicken Vasa homologue) mediates the reprogramming of chicken embryonic stem cells to a germ cell fate.

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    Lavial, Fabrice; Acloque, Hervé; Bachelard, Elodie; Nieto, M Angela; Samarut, Jacques; Pain, Bertrand

    2009-06-01

    When they are derived from blastodermal cells of the pre-primitive streak in vitro, the pluripotency of Chicken Embryonic Stem Cells (cESC) can be controlled by the cPouV and Nanog genes. These cESC can differentiate into derivatives of the three germ layers both in vitro and in vivo, but they only weakly colonize the gonads of host embryos. By contrast, non-cultured blastodermal cells and long-term cultured chicken primordial germ cells maintain full germline competence. This restriction in the germline potential of the cESC may result from either early germline determination in the donor embryos or it may occur as a result of in vitro culture. We are interested in understanding the genetic determinants of germline programming. The RNA binding protein Cvh (Chicken Vasa Homologue) is considered as one such determinant, although its role in germ cell physiology is still unclear. Here we show that the exogenous expression of Cvh, combined with appropriate culture conditions, induces cESC reprogramming towards a germ cell fate. Indeed, these cells express the Dazl, Tudor and Sycp3 germline markers, and they display improved germline colonization and adopt a germ cell fate when injected into recipient embryos. Thus, our results demonstrate that Vasa can drive ES cell differentiation towards the germ cell lineage, both in vitro and in vivo.

  15. 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.

  16. Myf5 haploinsufficiency reveals distinct cell fate potentials for adult skeletal muscle stem cells.

    Science.gov (United States)

    Gayraud-Morel, Barbara; Chrétien, Fabrice; Jory, Aurélie; Sambasivan, Ramkumar; Negroni, Elisa; Flamant, Patricia; Soubigou, Guillaume; Coppée, Jean-Yves; Di Santo, James; Cumano, Ana; Mouly, Vincent; Tajbakhsh, Shahragim

    2012-04-01

    Skeletal muscle stem cell fate in adult mice is regulated by crucial transcription factors, including the determination genes Myf5 and Myod. The precise role of Myf5 in regulating quiescent muscle stem cells has remained elusive. Here we show that most, but not all, quiescent satellite cells express Myf5 protein, but at varying levels, and that resident Myf5 heterozygous muscle stem cells are more primed for myogenic commitment compared with wild-type satellite cells. Paradoxically however, heterotypic transplantation of Myf5 heterozygous cells into regenerating muscles results in higher self-renewal capacity compared with wild-type stem cells, whereas myofibre regenerative capacity is not altered. By contrast, Pax7 haploinsufficiency does not show major modifications by transcriptome analysis. These observations provide a mechanism linking Myf5 levels to muscle stem cell heterogeneity and fate by exposing two distinct and opposing phenotypes associated with Myf5 haploinsufficiency. These findings have important implications for how stem cell fates can be modulated by crucial transcription factors while generating a pool of responsive heterogeneous cells.

  17. Vertebrate Ctr1 coordinates morphogenesis and progenitor cell fate and regulates embryonic stem cell differentiation

    OpenAIRE

    Haremaki, Tomomi; Fraser, Stuart T.; Kuo, Yien-Ming; Baron, Margaret H.; Weinstein, Daniel C.

    2007-01-01

    Embryogenesis involves two distinct processes. On the one hand, cells must specialize, acquiring fates appropriate to their positions (differentiation); on the other hand, they must physically construct the embryo through coordinated mechanical activity (morphogenesis). In early vertebrate development, fibroblast growth factor (FGF) regulates multiple embryonic events, including germ layer differentiation and morphogenesis; the cellular components that direct FGF signaling to evoke these diff...

  18. T Cell Fate at the Single-Cell Level.

    Science.gov (United States)

    Buchholz, Veit R; Schumacher, Ton N M; Busch, Dirk H

    2016-05-20

    T cell responses display two key characteristics. First, a small population of epitope-specific naive T cells expands by several orders of magnitude. Second, the T cells within this proliferating population take on diverse functional and phenotypic properties that determine their ability to exert effector functions and contribute to T cell memory. Recent technological advances in lineage tracing allow us for the first time to study these processes in vivo at single-cell resolution. Here, we summarize resulting data demonstrating that although epitope-specific T cell responses are reproducibly similar at the population level, expansion potential and diversification patterns of the offspring derived from individual T cells are highly variable during both primary and recall immune responses. In spite of this stochastic response variation, individual memory T cells can serve as adult stem cells that provide robust regeneration of an epitope-specific tissue through population averaging. We discuss the relevance of these findings for T cell memory formation and clinical immunotherapy.

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

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    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.

  20. 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.

  1. Potency and fate specification in CNS stem cell populations in vitro.

    Science.gov (United States)

    Ravin, Rea; Hoeppner, Daniel J; Munno, David M; Carmel, Liran; Sullivan, Jim; Levitt, David L; Miller, Jennifer L; Athaide, Christopher; Panchision, David M; McKay, Ronald D G

    2008-12-01

    To realize the promise of stem cell biology, it is important to identify the precise time in the history of the cell when developmental potential is restricted. To achieve this goal, we developed a real-time imaging system that captures the transitions in fate, generating neurons, astrocytes, and oligodendrocytes from single CNS stem cells in vitro. In the presence of bFGF, tripotent cells normally produce specified progenitors through a bipotent intermediate cell type. Surprisingly, the tripotent state is reset at each passage. The cytokine CNTF is thought to instruct multipotent cells to an astrocytic fate. We demonstrate that CNTF both directs astrogliogenesis from tripotent cells, bypassing two of the three normal bipotent intermediates, and later promotes the expansion of specified astrocytic progenitors. These results show how discrete cell types emerge from a multipotent cell and provide a strong basis for future studies to determine the molecular basis of fate specification.

  2. 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

  3. The MYB23 gene provides a positive feedback loop for cell fate specification in the Arabidopsis root epidermis.

    Science.gov (United States)

    Kang, Yeon Hee; Kirik, Victor; Hulskamp, Martin; Nam, Kyoung Hee; Hagely, Katherine; Lee, Myeong Min; Schiefelbein, John

    2009-04-01

    The specification of cell fates during development requires precise regulatory mechanisms to ensure robust cell type patterns. Theoretical models of pattern formation suggest that a combination of negative and positive feedback mechanisms are necessary for efficient specification of distinct fates in a field of differentiating cells. Here, we examine the role of the R2R3-MYB transcription factor gene, AtMYB23 (MYB23), in the establishment of the root epidermal cell type pattern in Arabidopsis thaliana. MYB23 is closely related to, and is positively regulated by, the WEREWOLF (WER) MYB gene during root epidermis development. Furthermore, MYB23 is able to substitute for the function of WER and to induce its own expression when controlled by WER regulatory sequences. We also show that the MYB23 protein binds to its own promoter, suggesting a MYB23 positive feedback loop. The localization of MYB23 transcripts and MYB23-green fluorescent protein (GFP) fusion protein, as well as the effect of a chimeric MYB23-SRDX repressor construct, links MYB23 function to the developing non-hair cell type. Using mutational analyses, we find that MYB23 is necessary for precise establishment of the root epidermal pattern, particularly under conditions that compromise the cell specification process. These results suggest that MYB23 participates in a positive feedback loop to reinforce cell fate decisions and ensure robust establishment of the cell type pattern in the Arabidopsis root epidermis.

  4. 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.

  5. You Are What You Eat: Linking Metabolic Asymmetry and Cell Fate Choice.

    Science.gov (United States)

    Landskron, Lisa; Knoblich, Juergen A

    2016-05-09

    To defend against pathogens, activated immune cells must rapidly produce diverse lymphocyte subtypes. In a recent report in Nature, Verbist et al. (2016) describe how a regulatory loop acting between metabolic and transcriptional programs, centered around the asymmetric cell division machinery and the proto-oncogene c-Myc, establishes distinct T cell fates.

  6. Phosphorylation of the Polarity Protein BASL Differentiates Asymmetric Cell Fate through MAPKs and SPCH.

    Science.gov (United States)

    Zhang, Ying; Guo, Xiaoyu; Dong, Juan

    2016-11-07

    Cell polarization is commonly used for the regulation of stem cell asymmetric division in both animals and plants. Stomatal development in Arabidopsis, a process that produces breathing pores in the epidermis, requires asymmetric cell division to differentiate highly specialized guard cells while maintaining a stem cell population [1, 2]. The BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) protein exhibits a polarized localization pattern in the cell and is required for differential cell fates resulting from asymmetric cell division [3]. The polarization of BASL is made possible by a positive feedback loop with a canonical mitogen-activated protein kinase (MAPK) pathway that recruits the MAPKK kinase YODA (YDA) and MAPK 6 (MPK6) to the cortical polarity site [4]. Here, we study BASL intracellular dynamics and show that the membrane-associated BASL is slowly replenished at the cortical polarity site and that the mobility is tightly linked to its phosphorylation status. Because BASL polarity is only exhibited by one daughter cell after an asymmetric cell division, we study how BASL differentially functions in the two daughter cells. The YDA MAPK cascade transduces upstream ligand-receptor signaling [5-13] to the transcription factor SPEECHLESS (SPCH), which controls stomatal initiation and is directly suppressed by MPK3/6-mediated phosphorylation [14, 15]. We show that BASL polarization leads to elevated nuclear MPK6 signaling and lowered SPCH abundance in one of the two daughter cells. Therefore, two daughter cells are differentiated by BASL polarity-mediated differential suppression of SPCH, which may provide developmental plasticity in plant stem cell asymmetric cell division (ACD).

  7. 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.

  8. 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.

  9. The microRNA-dependent cell fate of multipotent stromal cells differentiating to endothelial cells.

    Science.gov (United States)

    Cha, Min-Ji; Choi, Eunhyun; Lee, Seahyoung; Song, Byeong-Wook; Yoon, Cheesoon; Hwang, Ki-Chul

    2016-02-15

    In the endothelial recovery process, bone marrow-derived MSCs are a potential source of cells for both research and therapy, and their capacities to self-renew and to differentiate into all the cell types in the human body make them a promising therapeutic agent for remodeling cellular differentiation and a valuable resource for the treatment of many diseases. Based on the results provided in a miRNA database, we selected miRNAs with unique targets in cell fate-related signaling pathways. The tested miRNAs targeting GSK-3β (miR-26a), platelet-derived growth factor receptor, and CD133 (miR-26a and miR-29b) induced MSC differentiation into functional ECs, whereas miRNAs targeting VEGF receptor (miR-15, miR-144, miR-145, and miR-329) inhibited MSC differentiation into ECs through VEGF stimulation. In addition, the expression levels of these miRNAs were correlated with in vivo physiological endothelial recovery processes. These findings indicate that the miRNA expression profile is distinct for cells in different stages of differentiation from MSCs to ECs and that specific miRNAs can function as regulators of endothelialization.

  10. Cell-fate determination by ubiquitin-dependent regulation of translation.

    Science.gov (United States)

    Werner, Achim; Iwasaki, Shintaro; McGourty, Colleen A; Medina-Ruiz, Sofia; Teerikorpi, Nia; Fedrigo, Indro; Ingolia, Nicholas T; Rape, Michael

    2015-09-24

    Metazoan development depends on the accurate execution of differentiation programs that allow pluripotent stem cells to adopt specific fates. Differentiation requires changes to chromatin architecture and transcriptional networks, yet whether other regulatory events support cell-fate determination is less well understood. Here we identify the ubiquitin ligase CUL3 in complex with its vertebrate-specific substrate adaptor KBTBD8 (CUL3(KBTBD8)) as an essential regulator of human and Xenopus tropicalis neural crest specification. CUL3(KBTBD8) monoubiquitylates NOLC1 and its paralogue TCOF1, the mutation of which underlies the neurocristopathy Treacher Collins syndrome. Ubiquitylation drives formation of a TCOF1-NOLC1 platform that connects RNA polymerase I with ribosome modification enzymes and remodels the translational program of differentiating cells in favour of neural crest specification. We conclude that ubiquitin-dependent regulation of translation is an important feature of cell-fate determination.

  11. Cell-fate specification in the epidermis: a common patterning mechanism in the root and shoot.

    Science.gov (United States)

    Schiefelbein, John

    2003-02-01

    The specification of epidermal hairs in Arabidopsis provides a useful model for the study of pattern formation in plants. Although the distributions of hair cells in the root and shoot appear quite different, recent studies show that pattern formation in each relies on a common cassette of transcriptional regulators. During development in each organ, neighboring cells compete to express regulators that specify the primary cell fate (including WEREWOLF [WER]/GLABRA1 [GL1], GL3/bHLH, TRANSPARENT TESTA GLABRA [TTG], and GL2), as well as those that prevent their neighbors from adopting this fate (including CAPRICE [CPC] and TRIPTYCHON [TRY]). The basic mechanism of lateral inhibition with feedback that has been uncovered by recent studies provides a conceptual framework for understanding how patterns of cell fate in general may be specified during plant development.

  12. Vacuolar H+-translocating inorganic pyrophosphatase (Vpp1) marks partial aleurone cell fate in cereal endosperm development.

    Science.gov (United States)

    Wisniewski, Jean-Pierre; Rogowsky, Peter M

    2004-10-01

    Cereal endosperm is a model system for cell fate determination in plants. In wild-type plants the outermost endosperm cells adopt aleurone cell fate, while all underlying cells display starchy endosperm cell fate. Mutant analysis showed that cell fate is determined by position rather than lineage. To further characterise the precise cell fate of the outermost cells, we performed a differential screen and isolated the novel marker gene Vpp1 . It encodes a vacuolar H+-translocating inorganic pyrophosphatase (V-PPase) and is mainly expressed in kernels, leaves and tassels. In kernels, its expression is restricted to the aleurone layer with the maximum of expression shifting from the adaxial to the abaxial side during early stages. Together with three other marker genes Vpp1 was then used to analyse the cell fate of the outermost cells in Dap3 , Dap7 , cr4 and dek1 mutants, all of which have aberrant aleurone layers. In the Dap3 and Dap7 mutants the Vpp1 and Ltp2 markers but not the A1 and Zein markers were expressed in patches without aleurone indicating that the outermost cells had some but not all features of aleurone cells and did not simply adopt starchy endosperm cell fate. A similar result was obtained in the cr4 mutant, although Ltp2 expression was less generalised. In other Dap7 patches characterised by multiple aleurone-like cell layers the expression of Vpp1 and Ltp2 confirmed the aleurone cell fate of the cells in the additional cell layers. The analysis of dek1 mutants confirmed the starchy endosperm cell fate of the majority but not all outermost cells. Based on these data we propose a model suggesting a stepwise commitment to aleurone cell fate. Sequential steps are marked by the expression of Vpp1 , the expression of Ltp2 , the acquisition of a regular shape and thick walls and finally pigmentation coupled with A1 expression.

  13. p53 oligomerization status modulates cell fate decisions between growth, arrest and apoptosis.

    Science.gov (United States)

    Fischer, Nicholas W; Prodeus, Aaron; Malkin, David; Gariépy, Jean

    2016-12-01

    Mutations in the oligomerization domain of p53 are genetically linked to cancer susceptibility in Li-Fraumeni Syndrome. These mutations typically alter the oligomeric state of p53 and impair its transcriptional activity. Activation of p53 through tetramerization is required for its tumor suppressive function by inducing transcriptional programs that lead to cell fate decisions such as cell cycle arrest or apoptosis. How p53 chooses between these cell fate outcomes remains unclear. Here, we use 5 oligomeric variants of p53, including 2 novel p53 constructs, that yield either monomeric, dimeric or tetrameric forms of p53 and demonstrate that they induce distinct cellular activities and gene expression profiles that lead to different cell fate outcomes. We report that dimeric p53 variants are cytostatic and can arrest cell growth, but lack the ability to trigger apoptosis in p53-null cells. In contrast, p53 tetramers induce rapid apoptosis and cell growth arrest, while a monomeric variant is functionally inactive, supporting cell growth. In particular, the expression of pro-arrest CDKN1A and pro-apoptotic P53AIP1 genes are important cell fate determinants that are differentially regulated by the oligomeric state of p53. This study suggests that the most abundant oligomeric species of p53 present in resting cells, namely p53 dimers, neither promote cell growth or cell death and that shifting the oligomeric state equilibrium of p53 in cells toward monomers or tetramers is a key parameter in p53-based cell fate decisions.

  14. A blueprint for engineering cell fate: current technologies to reprogram cell identity

    Institute of Scientific and Technical Information of China (English)

    Samantha A Morris; George Q Daley

    2013-01-01

    Human diseases such as heart failure,diabetes,neurodegenerative disorders,and many others result from the deficiency or dysfunction of critical cell types.Strategies for therapeutic tissue repair or regeneration require the in vitro manufacture of clinically relevant quantities of defined cell types.In addition to transplantation therapy,the generation of otherwise inaccessible cells also permits disease modeling,toxicology testing and drug discovery in vitro.In this review,we discuss current strategies to manipulate the identity of abundant and accessible cells by differentiation from an induced pluripotent state or direct conversion between differentiated states.We contrast these approaches with recent advances employing partial reprogramming to facilitate lineage switching,and discuss the mechanisms underlying the engineering of cell fate.Finally,we address the current limitations of the field and how the resulting cell types can be assessed to ensure the production of medically relevant populations.

  15. Mitochondrial function provides instructive signals for activation-induced B-cell fates.

    OpenAIRE

    Jang, Kyoung-Jin; Mano, Hiroto; Aoki, Koji; Hayashi, Tatsunari; Muto, Akihiko; Nambu, Yukiko; Takahashi, Katsu; Itoh, Katsuhiko; Taketani, Shigeru; Stephen L Nutt; Igarashi, Kazuhiko; Shimizu, Akira; Sugai, Manabu

    2015-01-01

    During immune reactions, functionally distinct B-cell subsets are generated by stochastic processes, including class-switch recombination (CSR) and plasma cell differentiation (PCD). In this study, we show a strong association between individual B-cell fates and mitochondrial functions. CSR occurs specifically in activated B cells with increased mitochondrial mass and membrane potential, which augment mitochondrial reactive oxygen species (mROS), whereas PCD occurs in cells with decreased mit...

  16. 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.

  17. Single-cell RNA-seq and computational analysis using temporal mixture modelling resolves Th1/Tfh fate bifurcation in malaria

    Science.gov (United States)

    Lönnberg, Tapio; Svensson, Valentine; James, Kylie R.; Fernandez-Ruiz, Daniel; Sebina, Ismail; Montandon, Ruddy; Soon, Megan S. F.; Fogg, Lily G.; Nair, Arya Sheela; Liligeto, Urijah; Stubbington, Michael J. T.; Ly, Lam-Ha; Bagger, Frederik Otzen; Zwiessele, Max; Lawrence, Neil D.; Souza-Fonseca-Guimaraes, Fernando; Bunn, Patrick T.; Engwerda, Christian R.; Heath, William R.; Billker, Oliver; Stegle, Oliver; Haque, Ashraful; Teichmann, Sarah A.

    2017-01-01

    Differentiation of naïve CD4+ T cells into functionally distinct T helper subsets is crucial for the orchestration of immune responses. Due to extensive heterogeneity and multiple overlapping transcriptional programs in differentiating T cell populations, this process has remained a challenge for systematic dissection in vivo. By using single-cell transcriptomics and computational analysis using a temporal mixtures of Gaussian processes model, termed GPfates, we reconstructed the developmental trajectories of Th1 and Tfh cells during blood-stage Plasmodium infection in mice. By tracking clonality using endogenous TCR sequences, we first demonstrated that Th1/Tfh bifurcation had occurred at both population and single-clone levels. Next, we identified genes whose expression was associated with Th1 or Tfh fates, and demonstrated a T-cell intrinsic role for Galectin-1 in supporting a Th1 differentiation. We also revealed the close molecular relationship between Th1 and IL-10-producing Tr1 cells in this infection. Th1 and Tfh fates emerged from a highly proliferative precursor that upregulated aerobic glycolysis and accelerated cell cycling as cytokine expression began. Dynamic gene expression of chemokine receptors around bifurcation predicted roles for cell-cell in driving Th1/Tfh fates. In particular, we found that precursor Th cells were coached towards a Th1 but not a Tfh fate by inflammatory monocytes. Thus, by integrating genomic and computational approaches, our study has provided two unique resources, a database www.PlasmoTH.org, which facilitates discovery of novel factors controlling Th1/Tfh fate commitment, and more generally, GPfates, a modelling framework for characterizing cell differentiation towards multiple fates. PMID:28345074

  18. Steroids are required for epidermal cell fate establishment in Arabidopsis roots.

    Science.gov (United States)

    Kuppusamy, Kavitha T; Chen, Andrew Y; Nemhauser, Jennifer L

    2009-05-12

    The simple structure of Arabidopsis roots provides an excellent model system to study epidermal cell fate specification. Epidermal cells in contact with 2 underlying cortical cells differentiate into hair cells (H cells; trichoblasts), whereas cells that contact only a single cortical cell differentiate into mature hairless cells (N cells; atrichoblasts). This position-dependent patterning, in combination with the constrained orientation of cell divisions, results in hair and nonhair cell files running longitudinally along the root epidermis. Here, we present strong evidence that steroid hormones called brassinosteroids (BRs) are required to maintain position-dependent fate specification in roots. We show that BRs are required for normal expression levels and patterns of WEREWOLF (WER) and GLABRA2 (GL2), master regulators of epidermal patterning. Loss of BR signaling results in loss of hair cells in H positions, likely as a consequence of reduced expression of CAPRICE (CPC), a direct downstream target of WER. Our observations demonstrate that in addition to their well-known role in cell expansion, BRs play an essential role in directing cell fate.

  19. Cell fate in the Arabidopsis root epidermis is determined by competition between WEREWOLF and CAPRICE.

    Science.gov (United States)

    Song, Sang-Kee; Ryu, Kook Hui; Kang, Yeon Hee; Song, Jae Hyo; Cho, Young-Hee; Yoo, Sang-Dong; Schiefelbein, John; Lee, Myeong Min

    2011-11-01

    The root hair and nonhair cells in the Arabidopsis (Arabidopsis thaliana) root epidermis are specified by a suite of transcriptional regulators. Two of these are WEREWOLF (WER) and CAPRICE (CPC), which encode MYB transcription factors that are required for promoting the nonhair cell fate and the hair cell fate, respectively. However, the precise function and relationship between these transcriptional regulators have not been fully defined experimentally. Here, we examine these issues by misexpressing the WER gene using the GAL4-upstream activation sequence transactivation system. We find that WER overexpression in the Arabidopsis root tip is sufficient to cause epidermal cells to adopt the nonhair cell fate through direct induction of GLABRA2 (GL2) gene expression. We also show that GLABRA3 (GL3) and ENHANCER OF GLABRA3 (EGL3), two closely related bHLH proteins, are required for the action of the overexpressed WER and that WER interacts with these bHLHs in plant cells. Furthermore, we find that CPC suppresses the WER overexpression phenotype quantitatively. These results show that WER acts together with GL3/EGL3 to induce GL2 expression and that WER and CPC compete with one another to define cell fates in the Arabidopsis root epidermis.

  20. β‐catenin‐driven binary cell fate decisions in animal development

    Science.gov (United States)

    2016-01-01

    The Wnt/β‐catenin pathway plays key roles during animal development. In several species, β‐catenin is used in a reiterative manner to regulate cell fate diversification between daughter cells following division. This binary cell fate specification mechanism has been observed in animals that belong to very diverse phyla: the nematode Caenorhabditis elegans, the annelid Platynereis, and the ascidian Ciona. It may also play a role in the regulation of several stem cell lineages in vertebrates. While the molecular mechanism behind this binary cell fate switch is not fully understood, it appears that both secreted Wnt ligands and asymmetric cortical factors contribute to the generation of the difference in nuclear β‐catenin levels between daughter cells. β‐Catenin then cooperates with lineage specific transcription factors to induce the expression of novel sets of transcription factors at each round of divisions, thereby diversifying cell fate. WIREs Dev Biol 2016, 5:377–388. doi: 10.1002/wdev.228 For further resources related to this article, please visit the WIREs website. PMID:26952169

  1. Single-cell analysis of mixed-lineage states leading to a binary cell fate choice.

    Science.gov (United States)

    Olsson, Andre; Venkatasubramanian, Meenakshi; Chaudhri, Viren K; Aronow, Bruce J; Salomonis, Nathan; Singh, Harinder; Grimes, H Leighton

    2016-09-29

    Delineating hierarchical cellular states, including rare intermediates and the networks of regulatory genes that orchestrate cell-type specification, are continuing challenges for developmental biology. Single-cell RNA sequencing is greatly accelerating such research, given its power to provide comprehensive descriptions of genomic states and their presumptive regulators. Haematopoietic multipotential progenitor cells, as well as bipotential intermediates, manifest mixed-lineage patterns of gene expression at a single-cell level. Such mixed-lineage states may reflect the molecular priming of different developmental potentials by co-expressed alternative-lineage determinants, namely transcription factors. Although a bistable gene regulatory network has been proposed to regulate the specification of either neutrophils or macrophages, the nature of the transition states manifested in vivo, and the underlying dynamics of the cell-fate determinants, have remained elusive. Here we use single-cell RNA sequencing coupled with a new analytic tool, iterative clustering and guide-gene selection, and clonogenic assays to delineate hierarchical genomic and regulatory states that culminate in neutrophil or macrophage specification in mice. We show that this analysis captured prevalent mixed-lineage intermediates that manifested concurrent expression of haematopoietic stem cell/progenitor and myeloid progenitor cell genes. It also revealed rare metastable intermediates that had collapsed the haematopoietic stem cell/progenitor gene expression programme, instead expressing low levels of the myeloid determinants, Irf8 and Gfi1 (refs 9, 10, 11, 12, 13). Genetic perturbations and chromatin immunoprecipitation followed by sequencing revealed Irf8 and Gfi1 as key components of counteracting myeloid-gene-regulatory networks. Combined loss of these two determinants 'trapped' the metastable intermediate. We propose that mixed-lineage states are obligatory during cell-fate specification

  2. An emerging molecular mechanism for the neural vs mesodermal cell fate decision

    Institute of Scientific and Technical Information of China (English)

    Roman A Li; Kate G Storey

    2011-01-01

    @@ Understanding how primary cell fates are established and maintained in the vertebrate embryo provides important insights that inform directed in vitro differentiation of embryonic stem cells or adult cells that have undergone induced pluripotency.Neural differentiation is of particular interest as new neural cells may contribute to therapeutic approaches to nervous system injury and diseases and provide in vitro disease models for small molecule screening and for determining personalized drug treatments.

  3. Analytical control of process impurities in Pazopanib hydrochloride by impurity fate mapping.

    Science.gov (United States)

    Li, Yan; Liu, David Q; Yang, Shawn; Sudini, Ravinder; McGuire, Michael A; Bhanushali, Dharmesh S; Kord, Alireza S

    2010-08-01

    Understanding the origin and fate of organic impurities within the manufacturing process along with a good control strategy is an integral part of the quality control of drug substance. Following the underlying principles of quality by design (QbD), a systematic approach to analytical control of process impurities by impurity fate mapping (IFM) has been developed and applied to the investigation and control of impurities in the manufacturing process of Pazopanib hydrochloride, an anticancer drug approved recently by the U.S. FDA. This approach requires an aggressive chemical and analytical search for potential impurities in the starting materials, intermediates and drug substance, and experimental studies to track their fate through the manufacturing process in order to understand the process capability for rejecting such impurities. Comprehensive IFM can provide elements of control strategies for impurities. This paper highlights the critical roles that analytical sciences play in the IFM process and impurity control. The application of various analytical techniques (HPLC, LC-MS, NMR, etc.) and development of sensitive and selective methods for impurity detection, identification, separation and quantification are highlighted with illustrative examples. As an essential part of the entire control strategy for Pazopanib hydrochloride, analytical control of impurities with 'meaningful' specifications and the 'right' analytical methods is addressed. In particular, IFM provides scientific justification that can allow for control of process impurities up-stream at the starting materials or intermediates whenever possible.

  4. The roles and regulation of Sertoli cells in fate determinations of spermatogonial stem cells and spermatogenesis.

    Science.gov (United States)

    Hai, Yanan; Hou, Jingmei; Liu, Yun; Liu, Yang; Yang, Hao; Li, Zheng; He, Zuping

    2014-05-01

    Spermatogenesis is a complex process by which spermatogonial stem cells (SSCs) self-renew and differentiate into spermatozoa under the elaborate coordination of testicular microenvironment, namely, niche. Sertoli cells, which locate around male germ cells, are the most critical component of the niche. Significant progress has recently been made by peers and us on uncovering the effects of Sertoli cells on regulating fate determinations of SSCs. Here we addressed the roles and regulation of Sertoli cells in normal and abnormal spermatogenesis. Specifically, we summarized the biological characteristics of Sertoli cells, and we emphasized the roles of Sertoli cells in mediating the self-renewal, differentiation, apoptosis, de-differentiation, and trans-differentiation of SSCs. The association between abnormal function of Sertoli cells and impaired spermatogenesis was discussed. Finally, we highlighted several issues to be addressed for further investigation on the effects and mechanisms of Sertoli cells in spermatogenesis. Since Sertoli cells are the key supportive cells for SSCs and they are very receptive to modification, a better understanding of the roles and regulation of Sertoli cells in SSC biology and spermatogenesis would make it feasible to identify novel targets for gene therapy of male infertility as well as seek more efficient and safer strategies for male contraception.

  5. Medial HOXA genes demarcate haematopoietic stem cell fate during human development

    Science.gov (United States)

    Dou, Diana R.; Calvanese, Vincenzo; Sierra, Maria I.; Nguyen, Andrew T.; Minasian, Arazin; Saarikoski, Pamela; Sasidharan, Rajkumar; Ramirez, Christina M.; Zack, Jerome A.; Crooks, Gay M.; Galic, Zoran; Mikkola, Hanna K.A.

    2016-01-01

    Pluripotent stem cells (PSC) may provide a potential source of haematopoietic stem/progenitor cells (HSPCs) for transplantation; however, unknown molecular barriers prevent the self-renewal of PSC-HSPCs. Using two-step differentiation, human embryonic stem cells (hESCs) differentiated in vitro into multipotent haematopoietic cells that had CD34+CD38−/loCD90+CD45+GPI-80+ foetal liver (FL) HSC immunophenotype, but displayed poor expansion potential and engraftment ability. Transcriptome analysis of immunophenotypic hESC-HSPCs revealed that, despite their molecular resemblance to FL-HSPCs, medial HOXA genes remained suppressed. Knockdown of HOXA7 disrupted FL-HSPC function and caused transcriptome dysregulation that resembled hESC-derived progenitors. Overexpression of medial HOXA genes prolonged FL-HSPC maintenance but was insufficient to confer self-renewal to hESC-HSPCs. Stimulation of retinoic acid signalling during endothelial-to-haematopoietic transition induced the HOXA cluster and other HSC/definitive haemogenic endothelium genes, and prolonged HSPC maintenance in culture. Thus, retinoic acid signalling-induced medial HOXA gene expression marks the establishment of the definitive HSC fate and controls HSC identity and function. PMID:27183470

  6. 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

    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...... 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...

  7. A germline GFP transgenic axolotl and its use to track cell fate: dual origin of the fin mesenchyme during development and the fate of blood cells during regeneration.

    Science.gov (United States)

    Sobkow, Lidia; Epperlein, Hans-Henning; Herklotz, Stephan; Straube, Werner L; Tanaka, Elly M

    2006-02-15

    The development of transgenesis in axolotls is crucial for studying development and regeneration as it would allow for long-term cell fate tracing as well as gene expression analysis. We demonstrate here that plasmid injection into the one-cell stage axolotl embryo generates mosaic transgenic animals that display germline transmission of the transgene. The inclusion of SceI meganuclease in the injections (Thermes, V., Grabher, C., Ristoratore, F., Bourrat, F., Choulika, A., Wittbrodt, J., Joly, J.S., 2002. I-SceI meganuclease mediates highly efficient transgenesis in fish. Mech. Dev. 118, 91-98) resulted in a higher percentage of F0 animals displaying strong expression throughout the body. This represents the first demonstration in the axolotl of germline transmission of a transgene. Using this technique we have generated a germline transgenic animal expressing GFP ubiquitously in all tissues examined. We have used this animal to study cell fate in the dorsal fin during development. We have uncovered a contribution of somite cells to dorsal fin mesenchyme in the axolotl, which was previously assumed to derive solely from neural crest. We have also studied the role of blood during tail regeneration by transplanting the ventral blood-forming region from GFP+ embryos into unlabeled hosts. During tail regeneration, we do not observe GFP+ cells contributing to muscle or nerve, suggesting that during tail regeneration blood stem cells do not undergo significant plasticity.

  8. Single-cell mass spectrometry reveals small molecules that affect cell fates in the 16-cell embryo.

    Science.gov (United States)

    Onjiko, Rosemary M; Moody, Sally A; Nemes, Peter

    2015-05-26

    Spatial and temporal changes in molecular expression are essential to embryonic development, and their characterization is critical to understand mechanisms by which cells acquire different phenotypes. Although technological advances have made it possible to quantify expression of large molecules during embryogenesis, little information is available on metabolites, the ultimate indicator of physiological activity of the cell. Here, we demonstrate that single-cell capillary electrophoresis-electrospray ionization mass spectrometry is able to test whether differential expression of the genome translates to the domain of metabolites between single embryonic cells. Dissection of three different cell types with distinct tissue fates from 16-cell embryos of the South African clawed frog (Xenopus laevis) and microextraction of their metabolomes enabled the identification of 40 metabolites that anchored interconnected central metabolic networks. Relative quantitation revealed that several metabolites were differentially active between the cell types in the wild-type, unperturbed embryos. Altering postfertilization cytoplasmic movements that perturb dorsal development confirmed that these three cells have characteristic small-molecular activity already at cleavage stages as a result of cell type and not differences in pigmentation, yolk content, cell size, or position in the embryo. Changing the metabolite concentration caused changes in cell movements at gastrulation that also altered the tissue fates of these cells, demonstrating that the metabolome affects cell phenotypes in the embryo.

  9. 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.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. The Ca2+-induced methyltransferase xPRMT1b controls neural fate in amphibian embryo.

    Science.gov (United States)

    Batut, Julie; Vandel, Laurence; Leclerc, Catherine; Daguzan, Christiane; Moreau, Marc; Néant, Isabelle

    2005-10-18

    We have previously shown that an increase in intracellular Ca2+ is both necessary and sufficient to commit ectoderm to a neural fate in Xenopus embryos. However, the relationship between this Ca2+ increase and the expression of early neural genes has yet to be defined. Using a subtractive cDNA library between untreated and caffeine-treated animal caps, i.e., control ectoderm and ectoderm induced toward a neural fate by a release of Ca2+, we have isolated the arginine N-methyltransferase, xPRMT1b, a Ca2+-induced target gene, which plays a pivotal role in this process. First, we show in embryo and in animal cap that xPRMT1b expression is Ca2+-regulated. Second, overexpression of xPRMT1b induces the expression of early neural genes such as Zic3. Finally, in the whole embryo, antisense approach with morpholino oligonucleotide against xPRMT1b impairs neural development and in animal caps blocks the expression of neural markers induced by a release of internal Ca2+. Our results implicate an instructive role of an enzyme, an arginine methyltransferase protein, in the embryonic choice of determination between epidermal and neural fate. The results presented provide insights by which a Ca2+ increase induces neural fate.

  13. Mutant huntingtin regulates EGF receptor fate in non-neuronal cells lacking wild-type protein.

    Science.gov (United States)

    Melone, Mariarosa A B; Calarco, Anna; Petillo, Orsolina; Margarucci, Sabrina; Colucci-D'Amato, Luca; Galderisi, Umberto; Koverech, Guido; Peluso, Gianfranco

    2013-01-01

    Huntingtin (htt) is a scaffold protein localized at the subcellular level and is involved in coordinating the activity of several protein for signaling and intracellular transport. The emerging properties of htt in intracellular trafficking prompted us to study the role of mutant htt (polyQ-htt) in the intracellular fate of epidermal growth factor receptor (EGFR), whose activity seems to be strictly regulated by htt. In particular, to evaluate whether protein trafficking dysfunction occurs in non-neuronal cells in the absence of functional htt, we monitored the EGFR protein in fibroblasts from homozygotic HD patients and their healthy counterpart. We found that polyQ-htt controls EGFR degradation and recycling. Lack of wild-type htt caused alteration of the ubiquitination cycle, formation of EGFR-incorporating high-molecular weight protein aggregates and abnormal EGFR distribution in endosomes of the degradation and recycling pathways after EGF stimulation. PolyQ-htt-induced alteration of EGFR trafficking affected cell migration and proliferation, at least in part, through inhibition of ERK signaling. To our knowledge the data here reported represent the first signaling and phenotypic characterization of polyQ-htt involvement in the modulation of growth factor stimulation in non-neuronal cells.

  14. Specification of osteoblast cell fate by canonical Wnt signaling requires Bmp2.

    Science.gov (United States)

    Salazar, Valerie S; Ohte, Satoshi; Capelo, Luciane P; Gamer, Laura; Rosen, Vicki

    2016-12-01

    Enhanced BMP or canonical Wnt (cWnt) signaling are therapeutic strategies employed to enhance bone formation and fracture repair, but the mechanisms each pathway utilizes to specify cell fate of bone-forming osteoblasts remain poorly understood. Among all BMPs expressed in bone, we find that singular deficiency of Bmp2 blocks the ability of cWnt signaling to specify osteoblasts from limb bud or bone marrow progenitors. When exposed to cWnts, Bmp2-deficient cells fail to progress through the Runx2/Osx1 checkpoint and thus do not upregulate multiple genes controlling mineral metabolism in osteoblasts. Cells lacking Bmp2 after induction of Osx1 differentiate normally in response to cWnts, suggesting that pre-Osx1(+) osteoprogenitors are an essential source and a target of BMP2. Our analysis furthermore reveals Grainyhead-like 3 (Grhl3) as a transcription factor in the osteoblast gene regulatory network induced during bone development and bone repair, which acts upstream of Osx1 in a BMP2-dependent manner. The Runx2/Osx1 transition therefore receives crucial regulatory inputs from BMP2 that are not compensated for by cWnt signaling, and this is mediated at least in part by induction and activation of Grhl3.

  15. Feedbacks, Bifurcations, and Cell Fate Decision-Making in the p53 System

    Science.gov (United States)

    Bogdał, Marta N.; Lipniacki, Tomasz

    2016-01-01

    The p53 transcription factor is a regulator of key cellular processes including DNA repair, cell cycle arrest, and apoptosis. In this theoretical study, we investigate how the complex circuitry of the p53 network allows for stochastic yet unambiguous cell fate decision-making. The proposed Markov chain model consists of the regulatory core and two subordinated bistable modules responsible for cell cycle arrest and apoptosis. The regulatory core is controlled by two negative feedback loops (regulated by Mdm2 and Wip1) responsible for oscillations, and two antagonistic positive feedback loops (regulated by phosphatases Wip1 and PTEN) responsible for bistability. By means of bifurcation analysis of the deterministic approximation we capture the recurrent solutions (i.e., steady states and limit cycles) that delineate temporal responses of the stochastic system. Direct switching from the limit-cycle oscillations to the “apoptotic” steady state is enabled by the existence of a subcritical Neimark—Sacker bifurcation in which the limit cycle loses its stability by merging with an unstable invariant torus. Our analysis provides an explanation why cancer cell lines known to have vastly diverse expression levels of Wip1 and PTEN exhibit a broad spectrum of responses to DNA damage: from a fast transition to a high level of p53 killer (a p53 phosphoform which promotes commitment to apoptosis) in cells characterized by high PTEN and low Wip1 levels to long-lasting p53 level oscillations in cells having PTEN promoter methylated (as in, e.g., MCF-7 cell line). PMID:26928575

  16. Interrogating a cell signalling network sensitively monitors cell fate transition during early differentiation of mouse embryonic stem cells

    Institute of Scientific and Technical Information of China (English)

    LIU; Yi-Hsin; HO; Chih-ming

    2010-01-01

    The different cell types in an animal are often considered to be specified by combinations of transcription factors,and defined by marker gene expression.This paradigm is challenged,however,in stem cell research and application.Using a mouse embryonic stem cell(mESC) culture system,here we show that the expression level of many key stem cell marker genes/transcription factors such as Oct4,Sox2 and Nanog failed to monitor cell status transition during mESC differentiation.On the other hand,the response patterns of cell signalling network to external stimuli,as monitored by the dynamics of protein phosphorylation,changed dramatically.Our results also suggest that an irreversible alternation in the cell signalling network precedes the adjustment of transcription factor levels.This is consistent with the notion that signal transduction events regulate cell fate specification.We propose that interrogating a cell signalling network can assess the cell property more precisely,and provide a sensitive measurement for the early events in cell fate transition.We wish to bring attention to the potential problem of cell identification using a few marker genes,and suggest a novel methodology to address this issue.

  17. The effect of nutritional status and muscle fiber type on myogenic satellite cell fate and apoptosis.

    Science.gov (United States)

    Powell, D J; McFarland, D C; Cowieson, A J; Muir, W I; Velleman, S G

    2014-01-01

    Satellite cells (SC) are multipotential stem cells that can be induced by nutrition to alter their cellular developmental fate, which may vary depending on their fiber type origin. The objective of the current study was to determine the effect of restricting protein synthesis on inducing adipogenic transdifferentiation and apoptosis of SC originating from fibers of the fast glycolytic pectoralis major (p. major) and fast oxidative and glycolytic biceps femoris (b. femoris) muscles of the chicken. The availability of the essential sulfur amino acids Met and Cys was restricted to regulate protein synthesis during SC proliferation and differentiation. The SC were cultured and treated with 1 of 6 Met/Cys concentrations: 60/192, 30/96 (control), 7.5/24, 3/9.6, 1/3.2, or 0/0 mg/L. Reductions in Met/Cys concentrations from the control level resulted in increased lipid staining and expression of the adipogenic marker genes peroxisome proliferator-activated receptor gamma and stearoyl-CoA desaturase during differentiation in the p. major SC. Although b. femoris SC had increased lipid staining at lower Met/Cys concentrations, there was no increase in expression of either adipogenic gene. For both muscle types, SC Met/Cys, concentration above the control increased the expression of peroxisome proliferator-activated receptor gamma and stearoyl-CoA desaturase during differentiation. As Met/Cys concentration was decreased during proliferation, a dose-dependent decline in all apoptotic cells occurred except for early apoptotic cells in the p. major, which had no treatment effect (P nutrition on SC transdifferentiation to an adipogenic lineage and apoptosis, and the effect of fiber type on this response in an in vitro context.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Newman, Peter; Galenano-Niño, Jorge Luis; Graney, Pamela; Razal, Joselito M.; Minett, Andrew I.; Ribas, João; Ovalle-Robles, Raquel; Biro, Maté; Zreiqat, Hala

    2016-12-01

    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 alignment of topography, cell shape and cell differentiation to osteogenic and myogenic lineages. We show aligned topographies differentiate cells towards a satellite cell muscle progenitor state - a distinct cell myogenic lineage responsible for postnatal growth and repair of muscle. We analyze cell shape between the different topographies, using fluorescent time-lapse imaging over 21 days. In contrast to previous work, this allows the direct measurement of cell shape at a given time rather than defining the morphology of the underlying topography and neglecting cell shape. We report quantitative metrics of the time-based morphological behaviors of cell shape in response to differing topographies. This analysis offers insights into the relationship between topography, cell shape and cell differentiation. Cells differentiating towards a myogenic fate on aligned topographies adopt a characteristic elongated shape as well as the alignment of cells.

  20. Floor plate-derived sonic hedgehog regulates glial and ependymal cell fates in the developing spinal cord.

    Science.gov (United States)

    Yu, Kwanha; McGlynn, Sean; Matise, Michael P

    2013-04-01

    Cell fate specification in the CNS is controlled by the secreted morphogen sonic hedgehog (Shh). At spinal cord levels, Shh produced by both the notochord and floor plate (FP) diffuses dorsally to organize patterned gene expression in dividing neural and glial progenitors. Despite the fact that two discrete sources of Shh are involved in this process, the individual contribution of the FP, the only intrinsic source of Shh throughout both neurogenesis and gliogenesis, has not been clearly defined. Here, we have used conditional mutagenesis approaches in mice to selectively inactivate Shh in the FP (Shh(FP)) while allowing expression to persist in the notochord, which underlies the neural tube during neurogenesis but not gliogenesis. We also inactivated Smo, the common Hh receptor, in neural tube progenitors. Our findings confirm and extend prior studies suggesting an important requirement for Shh(FP) in specifying oligodendrocyte cell fates via repression of Gli3 in progenitors. Our studies also uncover a connection between embryonic Shh signaling and astrocyte-mediated reactive gliosis in adults, raising the possibility that this pathway is involved in the development of the most common cell type in the CNS. Finally, we find that intrinsic spinal cord Shh signaling is required for the proper formation of the ependymal zone, the epithelial cell lining of the central canal that is also an adult stem cell niche. Together, our studies identify a crucial late embryonic role for Shh(FP) in regulating the specification and differentiation of glial and epithelial cells in the mouse spinal cord.

  1. Stem-cell dynamics and lineage topology from in vivo fate mapping in the hematopoietic system.

    Science.gov (United States)

    Höfer, Thomas; Barile, Melania; Flossdorf, Michael

    2016-06-01

    In recent years, sophisticated fate-mapping tools have been developed to study the behavior of stem cells in the intact organism. These experimental approaches are beginning to yield a quantitative picture of how cell numbers are regulated during steady state and in response to challenges. Focusing on hematopoiesis and immune responses, we discuss how novel mathematical approaches driven by these fate-mapping data have provided insights into the dynamics and topology of cellular differentiation pathways in vivo. The combination of experiment and theory has allowed to quantify the degree of self-renewal in stem and progenitor cells, shown how native hematopoiesis differs fundamentally from post-transplantation hematopoiesis, and uncovered that the diversification of T lymphocytes during immune responses resembles tissue renewal driven by stem cells.

  2. JAK/STAT signaling regulates tissue outgrowth and male germline stem cell fate in Drosophila

    Institute of Scientific and Technical Information of China (English)

    Shree Ram SINGH; Xiu CHEN; Steven X.HOU

    2005-01-01

    In multicellular organisms, biological activities are regulated by cell signaling. The various signal transduction pathways regulate cell fate, proliferation, migration, and polarity. Miscoordination of the communicative signals will lead to disasters like cancer and other fatal diseases. The JAK/STAT signal transduction pathway is one of the pathways, which was first identified in vertebrates and is highly conserved throughout evolution. Studying the JAK/STAT signal transduction pathway in Drosophila provides an excellent opportunity to understand the molecular mechanism of the cell regulation during development and tumor formation. In this review, we discuss the general overview of JAK/STAT signaling in Drosophila with respect to its functions in the eye development and stem cell fate determination.

  3. Notch signaling and ghost cell fate in the calcifying cystig odontogenic tumor

    Directory of Open Access Journals (Sweden)

    Siar CH

    2011-11-01

    Full Text Available Abstract Notch signaling is an evolutionarily conserved mechanism that enables adjacent cells to adopt different fates. Ghost cells (GCs are anucleate cells with homogeneous pale eosinophilic cytoplasm and very pale to clear central areas (previous nucleus sites. Although GCs are present in a variety of odontogenic lesions notably the calcifying cystic odontogenic tumor (GCOT, their nature and process of formation remains elusive. The aim of this study was to investigate the role of Notch signaling in the cell fate specification of GCs in CCOT. Immunohistochemical staining for four Notch receptors (Notch1, Notch2, Notch3 and Notch4 and three ligands (Jagged1, Jagged2 and Delta1 was performed on archival tissues of five CCOT cases. Level of positivity was quantified as negative (0, mild (+, moderate (2+ and strong (3+. Results revealed that GCs demonstrated overexpression for Notch1 and Jagged1 suggesting that Notch1Jagged1 signaling might serve as the main transduction mechanism in cell fate decision for GCs in CCOT. Protein localizations were largely membranous and/or cytoplasmic. Mineralized GCs also stained positive implicating that the calcification process might be associated with upregulation of these molecules. The other Notch receptors and ligands were weak to absent in GCs and tumoral epithelium. Stromal endothelium and fibroblasts were stained variably positive.

  4. A new role of Klumpfuss in establishing cell fate during the GMC asymmetric cell division.

    Science.gov (United States)

    Gabilondo, Hugo; Losada-Pérez, María; Monedero, Ignacio; Torres-Herráez, Arturo; Molina, Isabel; Torroja, Laura; Benito-Sipos, Jonathan

    2014-11-01

    Studies in the Drosophila embryonic NB4-2 lineage have suggested that the transcription factor Klumpfuss (Klu) functions within embryonic neuroblast lineages to differentiate between the identities of two adjacent ganglion mother cells (GMCs). However, because of the limited lineage markers available, these observations have been made only for the NB4-2 lineage. Recent findings have placed this transcription factor in the vanguard of Drosophila neural stem cell biology by demonstrating that Klu is necessary for larval neuroblast growth and self-renewal. Here, we have studied the role of klu in an incipient model in order to address basic mechanisms of neural specification: the Va system. None of the previously reported roles of Klu satisfactorily explain our observations. Unexpectedly, in this lineage, klu is necessary for differentiating between the fates of the two neurons born from a unique GMC; klu mutants produce two B-type cells, rather than one B-type (Notch-OFF) and one A-type (Notch-ON) cell. Additionally, our results demonstrate that Klu operates in the GMC and/or in the newly born neuron, but not in the neuroblast. Unlike in larval neuroblasts in which Klu is an executor of Notch signaling, we have found that Klu does not lie downstream of the Notch pathway in this cell division context.

  5. Planar cell polarity effector gene Intu regulates cell fate-specific differentiation of keratinocytes through the primary cilia.

    Science.gov (United States)

    Dai, D; Li, L; Huebner, A; Zeng, H; Guevara, E; Claypool, D J; Liu, A; Chen, J

    2013-01-01

    Genes involved in the planar cell polarity (PCP) signaling pathway are essential for a number of developmental processes in mammals, such as convergent extension and ciliogenesis. Tissue-specific PCP effector genes of the PCP signaling pathway are believed to mediate PCP signals in a tissue- and cell type-specific manner. However, how PCP signaling controls the morphogenesis of mammalian tissues remains unclear. In this study, we investigated the role of inturned (Intu), a tissue-specific PCP effector gene, during hair follicle formation in mice. Tissue-specific disruption of Intu in embryonic epidermis resulted in hair follicle morphogenesis arrest because of the failure of follicular keratinocyte to differentiate. Targeting Intu in the epidermis resulted in almost complete loss of primary cilia in epidermal and follicular keratinocytes, and a suppressed hedgehog signaling pathway. Surprisingly, the epidermal stratification and differentiation programs and barrier function were not affected. These results demonstrate that tissue-specific PCP effector genes of the PCP signaling pathway control the differentiation of keratinocytes through the primary cilia in a cell fate- and context-dependent manner, which may be critical in orchestrating the propagation and interpretation of polarity signals established by the core PCP components.

  6. Evolution of a system sensitive to stochastic noise: P3.p cell fate in Caenorhabditis.

    Science.gov (United States)

    Pénigault, Jean-Baptiste; Félix, Marie-Anne

    2011-09-15

    The C. elegans cell lineage is overall invariant. One rare instance of variability concerns P3.p, the most anterior vulva precursor cell, which may either fuse with the epidermis without dividing, or remain competent to form vulval tissue and divide. Here we examine the evolutionary properties of this stochastic variation in P3.p fate. In the Caenorhabditis genus, high P3.p competence is ancestral and reduction in P3.p competence and division frequency occurred in C. sp. 14 and in a clade of nine species. Within this clade, the frequency of P3.p division further varies within and among species, being intermediate in C. elegans and low in C. briggsae. P3.p fate frequency is sensitive to random mutation accumulation, suggesting that this trait may evolve rapidly because of its sensitivity to mutational impact. P3.p fate depends on LIN-39/Hox5 expression and we find that the peak of LIN-39/Hox5 protein level is displaced posteriorly in C. briggsae compared to C. elegans. However, P3.p fate specification is most sensitive to the dose of EGL-20 and CWN-1, two Wnts that are secreted in a long-range gradient from the posterior end of C. elegans larvae (accompanying article). A half-dose of either of these Wnts is sufficient to affect division frequency in C. elegans N2 to levels similar to those in C. briggsae. Symmetrically, we show that an increase in Wnt dose rescues anterior competence in C. briggsae. We propose that evolutionary variation in the concentration or interpretation of the long-range Wnt gradient may be involved in the rapid evolution of P3.p fate in Caenorhabditis.

  7. Regulation of cell-fate decisions in T lymphocyte differenttiation

    NARCIS (Netherlands)

    M.C. Nawijn (Martijn)

    2000-01-01

    textabstractThe acquisition of protective immunity is essential for survival. Protective itmllunity can be divided in innate immunity and acquired immunity. These two parts of the immune system have evolved to closely interact. Cells of the innate immune system, such as dendritic cells and macrophag

  8. Epigenetic inheritance of cell fates during embryonic development

    Directory of Open Access Journals (Sweden)

    Sirisha eCheedipudi

    2014-02-01

    Full Text Available During embryonic development a large number of widely differing and specialized cell types with identical genomes are generated from a single totipotent zygote. Tissue specific transcription factors cooperate with epigenetic modifiers to establish cellular identity in differentiated cells and epigenetic regulatory mechanisms contribute to the maintenance of distinct chromatin states and cell-type specific gene expression patterns, a phenomenon referred to as epigenetic memory. This is accomplished via the stable maintenance of various epigenetic marks through successive rounds of cell division. Preservation of DNA methylation patterns is a well established mechanism of epigenetic memory, but more recently it has become clear that many other epigenetic modifications can also be maintained following DNA replication and cell division. In this review, we present an overview of the current knowledge regarding the role of histone lysine methylation in the establishment and maintenance of stable epigenetic states.

  9. Laminins affect T cell trafficking and allograft fate.

    Science.gov (United States)

    Warren, Kristi J; Iwami, Daiki; Harris, Donald G; Bromberg, Jonathan S; Burrell, Bryna E

    2014-05-01

    Lymph nodes (LNs) are integral sites for the generation of immune tolerance, migration of CD4⁺ T cells, and induction of Tregs. Despite the importance of LNs in regulation of inflammatory responses, the LN-specific factors that regulate T cell migration and the precise LN structural domains in which differentiation occurs remain undefined. Using intravital and fluorescent microscopy, we found that alloreactive T cells traffic distinctly into the tolerant LN and colocalize in exclusive regions with alloantigen-presenting cells, a process required for Treg induction. Extracellular matrix proteins, including those of the laminin family, formed regions within the LN that were permissive for colocalization of alloantigen-presenting cells, alloreactive T cells, and Tregs. We identified unique expression patterns of laminin proteins in high endothelial venule basement membranes and the cortical ridge that correlated with alloantigen-specific immunity or immune tolerance. The ratio of laminin α4 to laminin α5 was greater in domains within tolerant LNs, compared with immune LNs, and blocking laminin α4 function or inducing laminin α5 overexpression disrupted T cell and DC localization and transmigration through tolerant LNs. Furthermore, reducing α4 laminin circumvented tolerance induction and induced cardiac allograft inflammation and rejection in murine models. This work identifies laminins as potential targets for immune modulation.

  10. Mark the transition: chromatin modifications and cell fate decision

    Institute of Scientific and Technical Information of China (English)

    Qiang Wu; Huck-Hui Ng

    2011-01-01

    With their unique features of selfrenewal and pluripotency,human embryonic stem (hES) cells are considered to be a nearly unlimited resource for research and clinical applications [1].Accordingly,the transcriptional network specifying and governing human ES cell identity has been extensively studied.OCT4,NANOG and SOX2 form a core transcriptional network that regulates itself as well as a number of target genes [2].This transcriptional network acts together with signaling pathways to maintain ES cell identity [3].Moreover,the last decade has seen tremendous advances in understanding the epigenetic mechanisms underlying ES eell self-renewal and pluripotency.

  11. Retinoic acid, meiosis and germ cell fate in mammals.

    Science.gov (United States)

    Bowles, Josephine; Koopman, Peter

    2007-10-01

    Although mammalian sex is determined genetically, the sex-specific development of germ cells as sperm or oocytes is initiated by cues provided by the gonadal environment. During embryogenesis, germ cells in an ovary enter meiosis, thereby committing to oogenesis. By contrast, germ cells in a testicular environment do not enter meiosis until puberty. Recent findings indicate that the key to this sex-specific timing of meiosis entry is the presence or absence of the signaling molecule retinoic acid. Although this knowledge clarifies a long-standing mystery in reproductive biology, it also poses many new questions, which we discuss in this review.

  12. 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.

  13. Evidence for a critical role of gene occlusion in cell fate restriction

    Institute of Scientific and Technical Information of China (English)

    Jedidiah Gaetz; Wei-Hua Yu; Andy Peng Xiang; Bruce T Lahn; Kayla L Clift; Croydon J Fernandes; Frank Fuxiang Mao; Jae Hyun Lee; Li Zhang; Samuel W Baker; Timothy J Looney; Kara M Foshay

    2012-01-01

    The progressive restriction of cell fate during lineage differentiation is a poorly understood phenomenon despite its ubiquity in multicellular organisms.We recently used a cell fusion assay to define a mode of epigenetic silencing that we termed "occlusion",wherein affected genes are silenced by cis-acting chromatin mechanisms irrespective of whether trans-acting transcriptional activators are present.We hypothesized that occlusion of lineage-inappropriate genes could contribute to cell fate restriction.Here,we test this hypothesis by introducing bacterial artificial chromosomes (BACs),which are devoid of chromatin modifications necessary for occlusion,into mouse fibroblasts.We found that BAC transgenes corresponding to occluded endogenous genes are expressed in most eases,whereas BAC transgenes corresponding to silent but non-occluded endogenous genes are not expressed.This indicates that the cellular milieu in trans supports the expression of most occluded genes in fibroblasts,and that the silent state of these genes is solely the consequence of occlusion in cis.For the BAC corresponding to the occluded myogenic master regulator Myf5,expression of the Myf5 transgene on the BAC triggered fibroblasts to acquire a muscle-like phenotype.These results provide compelling evidence for a critical role of gene occlusion in cell fate restriction.

  14. Ptf1a triggers GABAergic neuronal cell fates in the retina

    Directory of Open Access Journals (Sweden)

    Parain Karine

    2007-10-01

    Full Text Available Abstract Background In recent years, considerable knowledge has been gained on the molecular mechanisms underlying retinal cell fate specification. However, hitherto studies focused primarily on the six major retinal cell classes (five types of neurons of one type of glial cell, and paid little attention to the specification of different neuronal subtypes within the same cell class. In particular, the molecular machinery governing the specification of the two most abundant neurotransmitter phenotypes in the retina, GABAergic and glutamatergic, is largely unknown. In the spinal cord and cerebellum, the transcription factor Ptf1a is essential for GABAergic neuron production. In the mouse retina, Ptf1a has been shown to be involved in horizontal and most amacrine neurons differentiation. Results In this study, we examined the distribution of neurotransmitter subtypes following Ptf1a gain and loss of function in the Xenopus retina. We found cell-autonomous dramatic switches between GABAergic and glutamatergic neuron production, concomitant with profound defects in the genesis of amacrine and horizontal cells, which are mainly GABAergic. Therefore, we investigated whether Ptf1a promotes the fate of these two cell types or acts directly as a GABAergic subtype determination factor. In ectodermal explant assays, Ptf1a was found to be a potent inducer of the GABAergic subtype. Moreover, clonal analysis in the retina revealed that Ptf1a overexpression leads to an increased ratio of GABAergic subtypes among the whole amacrine and horizontal cell population, highlighting its instructive capacity to promote this specific subtype of inhibitory neurons. Finally, we also found that within bipolar cells, which are typically glutamatergic interneurons, Ptf1a is able to trigger a GABAergic fate. Conclusion Altogether, our results reveal for the first time in the retina a major player in the GABAergic versus glutamatergic cell specification genetic pathway.

  15. 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.

  16. Controlling Cell Function with Geometry

    Science.gov (United States)

    Mrksich, Milan

    2012-02-01

    This presentation will describe the use of patterned substrates to control cell shape with examples that illustrate the ways in which cell shape can regulate cell function. Most cells are adherent and must attach to and spread on a surface in order to survive, proliferate and function. In tissue, this surface is the extracellular matrix (ECM), an insoluble scaffold formed by the assembly of several large proteins---including fibronectin, the laminins and collagens and others---but in the laboratory, the surface is prepared by adsorbing protein to glass slides. To pattern cells, gold-coated slides are patterned with microcontact printing to create geometric features that promote cell attachment and that are surrounded by inert regions. Cells attach to these substrates and spread to adopt the shape defined by the underlying pattern and remain stable in culture for several days. Examples will be described that used a series of shapes to reveal the relationship between the shape of the cell and the structure of its cytoskeleton. These geometric cues were used to control cell polarity and the tension, or contractility, present in the cytoskeleton. These rules were further used to control the shapes of mesenchymal stem cells and in turn to control the differentiation of these cells into specialized cell types. For example, stem cells that were patterned into a ``star'' shape preferentially differentiated into bone cells whereas those that were patterned into a ``flower'' shape preferred a fat cell fate. These influences of shape on differentiation depend on the mechanical properties of the cytoskeleton. These examples, and others, reveal that shape is an important cue that informs cell function and that can be combined with the more common soluble cues to direct and study cell function.

  17. Putting it all on pigmentation: Heuristics of a bold and stochastic cell fate decision.

    Science.gov (United States)

    Xing, Jianhua; Lee, Robin E C

    2015-10-06

    Gradients of transmembrane potential coordinate cell-fate decisions and patterning during embryogenesis and wound-healing. Bioelectrical signaling may also be more important for adult pathologies than currently recognized. In this issue of Science Signaling, Lobikin et al. describe a role for bioelectric signals during the development of Xenopus leavis embryos to instruct an organism-level response reminiscent of neoplastic progression in melanoma.

  18. 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 toti

  19. Oriented growth and transdifferentiation of mesenchymal stem cells towards a Schwann cell fate on micropatterned substrates.

    Science.gov (United States)

    Sharma, Anup D; Zbarska, Svitlana; Petersen, Emma M; Marti, Mustafa E; Mallapragada, Surya K; Sakaguchi, Donald S

    2016-03-01

    While Schwann cells (SCs) have a significant role in peripheral nerve regeneration, their use in treatments has been limited because of lack of a readily available source. To address this issue, this study focused on the effect of guidance cues by employing micropatterned polymeric films to influence the alignment, morphology and transdifferentiation of bone marrow-derived rat mesenchymal stem cells (MSCs) towards a Schwann cell-like fate. Two different types of polymers, biocompatible polystyrene (PS) and biodegradable poly(lactic acid) (PLA) were used to fabricate patterned films. Percentages of transdifferentiated MSCs (tMSCs) immunolabeled with SC markers (α-S100β and α-p75(NTR)) were found to be similar on patterned versus smooth PS and PLA substrates. However, patterning had a significant effect on the alignment and elongation of the tMSCs. More than 80% of the tMSCs were oriented in the direction of microgrooves (0°-20°), while cells on the smooth substrates were randomly oriented. The aspect ratio [AR, ratio of length (in direction of microgrooves) and breadth (in direction perpendicular to microgrooves)] of the tMSCs on patterned substrates had a value of approximately five, as compared to cells on smooth substrates where the AR was one. Understanding responses to these cues in vitro helps us in understanding the behavior and interaction of the cells with the 3D environment of the scaffolds, facilitating the application of these concepts to designing effective nerve guidance conduits for peripheral nerve regeneration.

  20. 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.

  1. Laminopathies disrupt epigenomic developmental programs and cell fate.

    Science.gov (United States)

    Perovanovic, Jelena; Dell'Orso, Stefania; Gnochi, Viola F; Jaiswal, Jyoti K; Sartorelli, Vittorio; Vigouroux, Corinne; Mamchaoui, Kamel; Mouly, Vincent; Bonne, Gisèle; Hoffman, Eric P

    2016-04-20

    The nuclear envelope protein lamin A is encoded by thelamin A/C(LMNA) gene, which can contain missense mutations that cause Emery-Dreifuss muscular dystrophy (EDMD) (p.R453W). We fused mutated forms of the lamin A protein to bacterial DNA adenine methyltransferase (Dam) to define euchromatic-heterochromatin (epigenomic) transitions at the nuclear envelope during myogenesis (using DamID-seq). Lamin A missense mutations disrupted appropriate formation of lamin A-associated heterochromatin domains in an allele-specific manner-findings that were confirmed by chromatin immunoprecipitation-DNA sequencing (ChIP-seq) in murine H2K cells and DNA methylation studies in fibroblasts from muscular dystrophy patient who carried a distinctLMNAmutation (p.H222P). Observed perturbations of the epigenomic transitions included exit from pluripotency and cell cycle programs [euchromatin (open, transcribed) to heterochromatin (closed, silent)], as well as induction of myogenic loci (heterochromatin to euchromatin). In muscle biopsies from patients with either a gain- or change-of-functionLMNAgene mutation or a loss-of-function mutation in theemeringene, both of which cause EDMD, we observed inappropriate loss of heterochromatin formation at theSox2pluripotency locus, which was associated with persistent mRNA expression ofSox2 Overexpression ofSox2inhibited myogenic differentiation in human immortalized myoblasts. Our findings suggest that nuclear envelopathies are disorders of developmental epigenetic programming that result from altered formation of lamina-associated domains.

  2. 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.

  3. Human Induced Pluripotent Cell-Derived Sensory Neurons for Fate Commitment of Bone Marrow-Derived Schwann Cells: Implications for Remyelination Therapy.

    Science.gov (United States)

    Cai, Sa; Han, Lei; Ao, Qiang; Chan, Ying-Shing; Shum, Daisy Kwok-Yan

    2016-09-14

    : Strategies that exploit induced pluripotent stem cells (iPSCs) to derive neurons have relied on cocktails of cytokines and growth factors to bias cell-signaling events in the course of fate choice. These are often costly and inefficient, involving multiple steps. In this study, we took an alternative approach and selected 5 small-molecule inhibitors of key signaling pathways in an 8-day program to induce differentiation of human iPSCs into sensory neurons, reaching ≥80% yield in terms of marker proteins. Continuing culture in maintenance medium resulted in neuronal networks immunopositive for synaptic vesicle markers and vesicular glutamate transporters suggestive of excitatory neurotransmission. Subpopulations of the derived neurons were electrically excitable, showing tetrodotoxin-sensitive action potentials in patch-clamp experiments. Coculture of the derived neurons with rat Schwann cells under myelinating conditions resulted in upregulated levels of neuronal neuregulin 1 type III in conjunction with the phosphorylated receptors ErbB2 and ErbB3, consistent with amenability of the neuritic network to myelination. As surrogates of embryonic dorsal root ganglia neurons, the derived sensory neurons provided contact-dependent cues to commit bone marrow-derived Schwann cell-like cells to the Schwann cell fate. Our rapid and efficient induction protocol promises not only controlled differentiation of human iPSCs into sensory neurons, but also utility in the translation to a protocol whereby human bone marrow-derived Schwann cells become available for autologous transplantation and remyelination therapy.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  6. Predicting pancreas cell fate decisions and reprogramming with a hierarchical multi-attractor model.

    Directory of Open Access Journals (Sweden)

    Joseph Xu Zhou

    Full Text Available Cell fate reprogramming, such as the generation of insulin-producing β cells from other pancreas cells, can be achieved by external modulation of key transcription factors. However, the known gene regulatory interactions that form a complex network with multiple feedback loops make it increasingly difficult to design the cell reprogramming scheme because the linear regulatory pathways as schemes of causal influences upon cell lineages are inadequate for predicting the effect of transcriptional perturbation. However, sufficient information on regulatory networks is usually not available for detailed formal models. Here we demonstrate that by using the qualitatively described regulatory interactions as the basis for a coarse-grained dynamical ODE (ordinary differential equation based model, it is possible to recapitulate the observed attractors of the exocrine and β, δ, α endocrine cells and to predict which gene perturbation can result in desired lineage reprogramming. Our model indicates that the constraints imposed by the incompletely elucidated regulatory network architecture suffice to build a predictive model for making informed decisions in choosing the set of transcription factors that need to be modulated for fate reprogramming.

  7. Sr-substituted bone cements direct mesenchymal stem cells, osteoblasts and osteoclasts fate

    Science.gov (United States)

    Panseri, Silvia; Dapporto, Massimiliano; Tampieri, Anna; Sprio, Simone

    2017-01-01

    Strontium-substituted apatitic bone cements enriched with sodium alginate were developed as a potential modulator of bone cells fate. The biological impact of the bone cement were investigated in vitro through the study of the effect of the nanostructured apatitic composition and the doping of strontium on mesenchymal stem cells, pre-osteoblasts and osteoclasts behaviours. Up to 14 days of culture the bone cells viability, proliferation, morphology and gene expression profiles were evaluated. The results showed that different concentrations of strontium were able to evoke a cell-specific response, in fact an inductive effect on mesenchymal stem cells differentiation and pre-osteoblasts proliferation and an inhibitory effect on osteoclasts activity were observed. Moreover, the apatitic structure of the cements provided a biomimetic environment suitable for bone cells growth. Therefore, the combination of biological features of this bone cement makes it as promising biomaterials for tissue regeneration. PMID:28196118

  8. Notch signaling differentially regulates the cell fate of early endocrine precursor cells and their maturing descendants in the mouse pancreas and intestine.

    Science.gov (United States)

    Li, Hui Joyce; Kapoor, Archana; Giel-Moloney, Maryann; Rindi, Guido; Leiter, Andrew B

    2012-11-15

    Notch signaling inhibits differentiation of endocrine cells in the pancreas and intestine. In a number of cases, the observed inhibition occurred with Notch activation in multipotential cells, prior to the initiation of endocrine differentiation. It has not been established how direct activation of Notch in endocrine precursor cells affects their subsequent cell fate. Using conditional activation of Notch in cells expressing Neurogenin3 or NeuroD1, we examined the effects of Notch in both organs, on cell fate of early endocrine precursors and maturing endocrine-restricted cells, respectively. Notch did not preclude the differentiation of a limited number of endocrine cells in either organ when activated in Ngn3(+) precursor cells. In addition, in the pancreas most Ngn3(+) cells adopted a duct but not acinar cell fate; whereas in intestinal Ngn3(+) cells, Notch favored enterocyte and goblet cell fates, while selecting against endocrine and Paneth cell differentiation. A small fraction of NeuroD1(+) cells in the pancreas retain plasticity to respond to Notch, giving rise to intraislet ductules as well as cells with no detectable pancreatic lineage markers that appear to have limited ultrastructural features of both endocrine and duct cells. These results suggest that Notch directly regulates cell fate decisions in multipotential early endocrine precursor cells. Some maturing endocrine-restricted NeuroD1(+) cells in the pancreas switch to the duct lineage in response to Notch, indicating previously unappreciated plasticity at such a late stage of endocrine differentiation.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Sex determination. foxl3 is a germ cell-intrinsic factor involved in sperm-egg fate decision in medaka.

    Science.gov (United States)

    Nishimura, Toshiya; Sato, Tetsuya; Yamamoto, Yasuhiro; Watakabe, Ikuko; Ohkawa, Yasuyuki; Suyama, Mikita; Kobayashi, Satoru; Tanaka, Minoru

    2015-07-17

    Sex determination is an essential step in the commitment of a germ cell to a sperm or egg. However, the intrinsic factors that determine the sexual fate of vertebrate germ cells are unknown. Here, we show that foxl3, which is expressed in germ cells but not somatic cells in the gonad, is involved in sperm-egg fate decision in medaka fish. Adult XX medaka with disrupted foxl3 developed functional sperm in the expanded germinal epithelium of a histologically functional ovary. In chimeric medaka, mutant germ cells initiated spermatogenesis in female wild-type gonad. These results indicate that a germ cell-intrinsic cue for the sperm-egg fate decision is present in medaka and that spermatogenesis can proceed in a female gonadal environment.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Machine learning classification of cell-specific cardiac enhancers uncovers developmental subnetworks regulating progenitor cell division and cell fate specification.

    Science.gov (United States)

    Ahmad, Shaad M; Busser, Brian W; Huang, Di; Cozart, Elizabeth J; Michaud, Sébastien; Zhu, Xianmin; Jeffries, Neal; Aboukhalil, Anton; Bulyk, Martha L; Ovcharenko, Ivan; Michelson, Alan M

    2014-02-01

    The Drosophila heart is composed of two distinct cell types, the contractile cardial cells (CCs) and the surrounding non-muscle pericardial cells (PCs), development of which is regulated by a network of conserved signaling molecules and transcription factors (TFs). Here, we used machine learning with array-based chromatin immunoprecipitation (ChIP) data and TF sequence motifs to computationally classify cell type-specific cardiac enhancers. Extensive testing of predicted enhancers at single-cell resolution revealed the added value of ChIP data for modeling cell type-specific activities. Furthermore, clustering the top-scoring classifier sequence features identified novel cardiac and cell type-specific regulatory motifs. For example, we found that the Myb motif learned by the classifier is crucial for CC activity, and the Myb TF acts in concert with two forkhead domain TFs and Polo kinase to regulate cardiac progenitor cell divisions. In addition, differential motif enrichment and cis-trans genetic studies revealed that the Notch signaling pathway TF Suppressor of Hairless [Su(H)] discriminates PC from CC enhancer activities. Collectively, these studies elucidate molecular pathways used in the regulatory decisions for proliferation and differentiation of cardiac progenitor cells, implicate Su(H) in regulating cell fate decisions of these progenitors, and document the utility of enhancer modeling in uncovering developmental regulatory subnetworks.

  13. Sequoia regulates cell fate decisions in the external sensory organs of adult Drosophila.

    Science.gov (United States)

    Andrews, Hillary K; Giagtzoglou, Nikolaos; Yamamoto, Shinya; Schulze, Karen L; Bellen, Hugo J

    2009-06-01

    The adult Drosophila external sensory organ (ESO), comprising the hair, socket, neuron, sheath and glia cells, arises through the asymmetric division of sensory organ precursor cells (SOPs). In a mosaic screen designed to identify new components in ESO development, we isolated mutations in sequoia, which encodes a putative zinc-finger transcription factor that has previously been shown to have a role in dendritogenesis. Here, we show that adult clones mutant for seq exhibit a loss of hair cells and a gain of socket cells. We propose that the seq mutant phenotype arises, in part, owing to the loss of several crucial transcription factors known to be important in peripheral nervous system development such as D-Pax2, Prospero and Hamlet. Thus, Sequoia is a new upstream regulator of genes that orchestrates cell fate specification during development of the adult ESO lineage.

  14. The developmental fate of green fluorescent mouse embryonic germ cells in chimeric embryos

    Institute of Scientific and Technical Information of China (English)

    XUXIN; SUMIOSUGANO; 等

    1999-01-01

    Primordial germ cells (PGCs),as precursors of mammalian germ lineage,have been gaining more attention as a new resource of pluripotent stem cells,which bring a great possibility to study developmental events of germ cell in vitro and at animal level.EG4 cells derived from 10.5 days post coitum (dpc) PGCs of 129/svJ strain mouse were established and maintained in an undifferentiated state.With an attempt to study the differentiation capability of EG4 cells with a reporter protein:green fluorescence protein,and the possible application of EG4 cells in the research of germ cell development,we have generated several EG4-GFP cell lines expressing enhanced green fluorescence protein (EGFP) and still maintaining typical characteristics of pluripotent stem cells.Then,the differentiation of EG4-GFP cells in vitro as well as their developmental fate in chimeric embryos which were produced by aggregating EG4-GFP cells to 8-cell stage embryos were studied.The results showed that EG4 cells carrying green fluorescence have a potential use in the research of germ cell development and other related studies.

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

    Science.gov (United States)

    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.

  16. 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.

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

    Directory of Open Access Journals (Sweden)

    Claudia Cattoglio

    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.

  18. Microbe-associated immunomodulatory metabolites: Influence on T cell fate and function.

    Science.gov (United States)

    Castro, C N; Freitag, J; Berod, L; Lochner, M; Sparwasser, T

    2015-12-01

    During the past two decades, a growing interest surrounding the interaction between microbe-associated molecular patterns (MAMPs) and pattern recognition receptors has occurred. This attention is now driven alongside bacterial-derived metabolites, which impact immune cell differentiation and function. Hence, this review introduces the term meta-MAMP as a means to classify the microbial derived-metabolites, which influence the immune response by affecting specific cellular processes. We discuss two prominent examples of meta-MAMPs: the first, rapamycin (isolated from Streptomyces), was discovered in the 1970s and since then has been thoroughly studied. The second, soraphen A (isolated from Myxobacteria), was discovered in the early 1990s but only recently identified as a promising immunomodulator. Both meta-MAMPs are similar in their remarkable capacity to modulate T cell fate by targeting key metabolic pathways triggered upon T cell activation. In this context, we highlight the progress made in the field of immunometabolism and the possibility of modulating metabolic pathways such as cellular fatty acid metabolism as a strategy for immunomodulation. We focus on the use of microbial metabolites as auspicious agents for T cell fate modulation.

  19. 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

    2015-02-01

    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.

  20. Dominant effects of Δ40p53 on p53 function and melanoma cell fate

    OpenAIRE

    2013-01-01

    The p53 gene encodes 12 distinct isoforms some of which can alter p53 activity in the absence of genomic alteration. Endogenous p53 isoforms have been identified in cancers; however, the function of these isoforms remains unclear. In melanoma, the frequency of p53 mutations is relatively low compared to other cancers suggesting that these isoforms may play a larger role in regulating p53 activity. We hypothesized that p53 function and therefore cell fate might be altered by the presence of Δ4...

  1. 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.

  2. Cell fate after mitotic arrest in different tumor cells is determined by the balance between slippage and apoptotic threshold

    Energy Technology Data Exchange (ETDEWEB)

    Galán-Malo, Patricia; Vela, Laura; Gonzalo, Oscar; Calvo-Sanjuán, Rubén; Gracia-Fleta, Lucía; Naval, Javier; Marzo, Isabel, E-mail: imarzo@unizar.es

    2012-02-01

    Microtubule poisons and other anti-mitotic drugs induce tumor death but the molecular events linking mitotic arrest to cell death are still not fully understood. We have analyzed cell fate after mitotic arrest produced by the microtubule-destabilizing drug vincristine in a panel of human tumor cell lines showing different response to vincristine. In Jurkat, RPMI 8226 and HeLa cells, apoptosis was triggered shortly after vincristine-induced mitotic arrest. However, A549 cells, which express a great amount of Bcl-x{sub L} and undetectable amounts of Bak, underwent mitotic slippage prior to cell death. However, when Bcl-x{sub L} gene was silenced in A549 cells, vincristine induced apoptosis during mitotic arrest. Another different behavior was found in MiaPaca2 cells, where vincristine caused death by mitotic catastrophe that switched to apoptosis when cyclin B1 degradation was prevented by proteasome inhibition. Overexpression of Bcl-x{sub L} or silencing Bax and Bak expression delayed the onset of apoptosis in Jurkat and RPMI 8226 cells, enabling mitotic slippage and endoreduplication. In HeLa cells, overexpression of Bcl-x{sub L} switched cell death from apoptosis to mitotic catastrophe. Mcl-1 offered limited protection to vincristine-induced cell death and Mcl-1 degradation was not essential for vincristine-induced death. All these results, taken together, indicate that the Bcl-x{sub L}/Bak ratio and the ability to degrade cyclin B1 determine cell fate after mitotic arrest in the different tumor cell types. Highlights: ► Vincristine induces cell death by apoptosis or mitotic catastrophe. ► Apoptosis-proficient cells die by apoptosis during mitosis upon vincristine treatment. ► p53wt apoptosis-deficient cells undergo apoptosis from a G1-like tetraploid state. ► p53mt apoptosis-deficient cells can survive and divide giving rise to 8N cells.

  3. Cell biology. Metabolic control of cell death.

    Science.gov (United States)

    Green, Douglas R; Galluzzi, Lorenzo; Kroemer, Guido

    2014-09-19

    Beyond their contribution to basic metabolism, the major cellular organelles, in particular mitochondria, can determine whether cells respond to stress in an adaptive or suicidal manner. Thus, mitochondria can continuously adapt their shape to changing bioenergetic demands as they are subjected to quality control by autophagy, or they can undergo a lethal permeabilization process that initiates apoptosis. Along similar lines, multiple proteins involved in metabolic circuitries, including oxidative phosphorylation and transport of metabolites across membranes, may participate in the regulated or catastrophic dismantling of organelles. Many factors that were initially characterized as cell death regulators are now known to physically or functionally interact with metabolic enzymes. Thus, several metabolic cues regulate the propensity of cells to activate self-destructive programs, in part by acting on nutrient sensors. This suggests the existence of "metabolic checkpoints" that dictate cell fate in response to metabolic fluctuations. Here, we discuss recent insights into the intersection between metabolism and cell death regulation that have major implications for the comprehension and manipulation of unwarranted cell loss.

  4. Estrogen receptor coregulators and pioneer factors: The orchestrators of mammary gland cell fate and development

    Directory of Open Access Journals (Sweden)

    Bramanandam eManavathi

    2014-08-01

    Full Text Available The 17-beta estradiol (E2, a steroid hormone, which play critical role in various cellular processes such as cell proliferation, differentiation, migration and apoptosis, is essential for reproduction and mammary gland development. E2 actions are mediated by two classical nuclear hormone receptors, estrogen receptor alpha and beta (ERs. The activity of ERs depends on the coordinate activity of ligand binding, posttranslational modification, and importantly their interaction with their partner proteins called ‘coregulators’. Because majority of breast cancers are ERalpha positive and coregulators are proved to be crucial for ER transcriptional activity, an increased interest in the field has led to the identification of a large number of coregulators. In the last decade, gene knockout studies using mouse models provided impetus to our further understanding of the role of these coregulators in mammary gland development. Several coregulators appear to be critical for terminal end bud formation, ductal branching and alveologenesis during mammary gland development. The emerging studies support that, in addition to these coregulators, the other ER partner proteins ‘pioneering factors’ also seems to contribute significantly to E2 signaling and mammary cell fate. This review discusses emerging themes in coregulator- and pioneering factor-mediated action on ER functions, particularly their role in mammary gland cell fate and development.

  5. Cdc42-mediated tubulogenesis controls cell specification

    DEFF Research Database (Denmark)

    Kesavan, Gokul; Sand, Fredrik Wolfhagen; Greiner, Thomas Uwe

    2009-01-01

    Understanding how cells polarize and coordinate tubulogenesis during organ formation is a central question in biology. Tubulogenesis often coincides with cell-lineage specification during organ development. Hence, an elementary question is whether these two processes are independently controlled......, or whether proper cell specification depends on formation of tubes. To address these fundamental questions, we have studied the functional role of Cdc42 in pancreatic tubulogenesis. We present evidence that Cdc42 is essential for tube formation, specifically for initiating microlumen formation and later...... for maintaining apical cell polarity. Finally, we show that Cdc42 controls cell specification non-cell-autonomously by providing the correct microenvironment for proper control of cell-fate choices of multipotent progenitors. For a video summary of this article, see the PaperFlick file with the Supplemental Data...

  6. Gene Regulatory Network Analysis Reveals Differences in Site-specific Cell Fate Determination in Mammalian Brain

    Directory of Open Access Journals (Sweden)

    Gokhan eErtaylan

    2014-12-01

    Full Text Available Neurogenesis - the generation of new neurons - is an ongoing process that persists in the adult mammalian brain of several species, including humans. In this work we analyze two discrete brain regions: the subventricular zone (SVZ lining the walls of the lateral ventricles; and the subgranular zone (SGZ of the dentate gyrus of the hippocampus in mice and shed light on the SVZ and SGZ specific neurogenesis. We propose a computational model that relies on the construction and analysis of region specific gene regulatory networks from the publicly available data on these two regions. Using this model a number of putative factors involved in neuronal stem cell (NSC identity and maintenance were identified. We also demonstrate potential gender and niche-derived differences based on cell surface and nuclear receptors via Ar, Hif1a and Nr3c1.We have also conducted cell fate determinant analysis for SVZ NSC populations to Olfactory Bulb interneurons and SGZ NSC populations to the granule cells of the Granular Cell Layer. We report thirty-one candidate cell fate determinant gene pairs, ready to be validated. We focus on Ar - Pax6 in SVZ and Sox2 - Ncor1 in SGZ. Both pairs are expressed and localized in the suggested anatomical structures as shown by in situ hybridization and found to physically interact.Finally, we conclude that there are fundamental differences between SGZ and SVZ neurogenesis. We argue that these regulatory mechanisms are linked to the observed differential neurogenic potential of these regions. The presence of nuclear and cell surface receptors in the region specific regulatory circuits indicate the significance of niche derived extracellular factors, hormones and region specific factors such as the oxygen sensitivity, dictating SGZ and SVZ specific neurogenesis.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. AID-induced remodeling of immunoglobulin genes and B cell fate.

    Science.gov (United States)

    Laffleur, Brice; Denis-Lagache, Nicolas; Péron, Sophie; Sirac, Christophe; Moreau, Jeanne; Cogné, Michel

    2014-03-15

    Survival and phenotype of normal and malignant B lymphocytes are critically dependent on constitutive signals by the B cell receptor (BCR) for antigen. In addition, either antigen ligation of the BCR or various mitogenic stimuli result in B cell activation and induction of activation-induced deaminase (AID). AID activity can in turn mediate somatic hypermutation (SHM) of immunoglobulin (Ig) V regions and also deeply remodel the Ig heavy chain locus through class switch recombination (CSR) or locus suicide recombination (LSR). In addition to changes linked to affinity for antigen, modifying the class/isotype (i.e. the structure and function) of the BCR or suddenly deleting BCR expression also modulates the fate of antigen-experienced B cells.

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

  10. A gene expression atlas of a bicoid-depleted Drosophila embryo reveals early canalization of cell fate.

    Science.gov (United States)

    Staller, Max V; Fowlkes, Charless C; Bragdon, Meghan D J; Wunderlich, Zeba; Estrada, Javier; DePace, Angela H

    2015-02-01

    In developing embryos, gene regulatory networks drive cells towards discrete terminal fates, a process called canalization. We studied the behavior of the anterior-posterior segmentation network in Drosophila melanogaster embryos by depleting a key maternal input, bicoid (bcd), and measuring gene expression patterns of the network at cellular resolution. This method results in a gene expression atlas containing the levels of mRNA or protein expression of 13 core patterning genes over six time points for every cell of the blastoderm embryo. This is the first cellular resolution dataset of a genetically perturbed Drosophila embryo that captures all cells in 3D. We describe the technical developments required to build this atlas and how the method can be employed and extended by others. We also analyze this novel dataset to characterize the degree and timing of cell fate canalization in the segmentation network. We find that in two layers of this gene regulatory network, following depletion of bcd, individual cells rapidly canalize towards normal cell fates. This result supports the hypothesis that the segmentation network directly canalizes cell fate, rather than an alternative hypothesis whereby cells are initially mis-specified and later eliminated by apoptosis. Our gene expression atlas provides a high resolution picture of a classic perturbation and will enable further computational modeling of canalization and gene regulation in this transcriptional network.

  11. 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.

  12. Polycomb protein EZH2 regulates cancer cell fate decision in response to DNA damage.

    Science.gov (United States)

    Wu, Z; Lee, S T; Qiao, Y; Li, Z; Lee, P L; Lee, Y J; Jiang, X; Tan, J; Aau, M; Lim, C Z H; Yu, Q

    2011-11-01

    Polycomb protein histone methyltransferase enhancer of Zeste homologe 2 (EZH2) is frequently overexpressed in human malignancy and is implicated in cancer cell proliferation and invasion. However, it is largely unknown whether EZH2 has a role in modulating DNA damage response. Here, we show that EZH2 is an important determinant of cell fate decision in response to genotoxic stress. EZH2 depletion results in abrogation of both cell cycle G1 and G2/M checkpoints, directing DNA damage response toward predominant apoptosis in both p53-proficient and p53-deficient cancer cells, but not in normal cells. Mechanistically, EZH2 regulates DNA damage response in p53 wild-type cells mainly through transcriptional repression of FBXO32, which binds to and directs p21 for proteasome-mediated degradation, whereas it affects p53-deficient cells through regulating Chk1 activation by a distinct mechanism. Furthermore, pharmacological depletion of EZH2 phenocopies the effects of EZH2 knockdown on cell cycle checkpoints and apoptosis. These data unravel a crucial role of EZH2 in determining the cancer cell outcome following DNA damage and suggest that therapeutic targeting oncogenic EZH2 might serve as a strategy for improving conventional chemotherapy in a given malignancy.

  13. Taenia taeniaeformis: fate and proliferation of mucosal cells during gastric hyperplasia in larvae infected rats.

    Science.gov (United States)

    Lagapa, J T; Oku, Y; Nonaka, N; Kamiya, M

    2008-04-01

    Fate and proliferation of gastric mucosal cells during hyperplasia of Taenia taeniaeformis eggs inoculated Wistar rats were investigated using PCNA immunohistochemistry, BrdU labeling and other histopathologic staining techniques. Results revealed marked cell proliferation in gastric corpus and antral mucosa of infected rats as evidenced by increased lengths of proliferative zones and indices of BrdU labeling. The gastropathy in corpus was characterized by massive accumulation of precursors, neck and intermediate cells following significant decreases in numbers of parietal and zymogenic cells. Gastropathy in antrum was described with significant increases in precursors and mucous cells. Our results suggested that T. taeniaeformis-induced gastric hyperplasia was initiated by depletion of parietal cells presumably due to the cestode's ES products. As a result, there was inhibition of zymogenic cell differentiation due to the disruption of normal development pathways of gastric mucosal lineages. These sequences of events were considered to cause the increase in cell proliferation and accumulation of intermediate cells resulting to the hyperplastic lesions.

  14. Modulated DISP3/PTCHD2 expression influences neural stem cell fate decisions

    Science.gov (United States)

    Konířová, Jana; Oltová, Jana; Corlett, Alicia; Kopycińska, Justyna; Kolář, Michal; Bartůněk, Petr; Zíková, Martina

    2017-01-01

    Neural stem cells (NSCs) are defined by their dual ability to self-renew through mitotic cell division or differentiate into the varied neural cell types of the CNS. DISP3/PTCHD2 is a sterol-sensing domain-containing protein, highly expressed in neural tissues, whose expression is regulated by thyroid hormone. In the present study, we used a mouse NSC line to investigate what effect DISP3 may have on the self-renewal and/or differentiation potential of the cells. We demonstrated that NSC differentiation triggered significant reduction in DISP3 expression in the resulting astrocytes, neurons and oligodendrocytes. Moreover, when DISP3 expression was disrupted, the NSC “stemness” was suppressed, leading to a larger population of cells undergoing spontaneous neuronal differentiation. Conversely, overexpression of DISP3 resulted in increased NSC proliferation. When NSCs were cultured under differentiation conditions, we observed that the lack of DISP3 augmented the number of NSCs differentiating into each of the neural cell lineages and that neuronal morphology was altered. In contrast, DISP3 overexpression resulted in impaired cell differentiation. Taken together, our findings imply that DISP3 may help dictate the NSC cell fate to either undergo self-renewal or switch to the terminal differentiation cell program. PMID:28134287

  15. Translational control in germline stem cell development.

    Science.gov (United States)

    Slaidina, Maija; Lehmann, Ruth

    2014-10-13

    Stem cells give rise to tissues and organs during development and maintain their integrity during adulthood. They have the potential to self-renew or differentiate at each division. To ensure proper organ growth and homeostasis, self-renewal versus differentiation decisions need to be tightly controlled. Systematic genetic studies in Drosophila melanogaster are revealing extensive regulatory networks that control the switch between stem cell self-renewal and differentiation in the germline. These networks, which are based primarily on mutual translational repression, act via interlocked feedback loops to provide robustness to this important fate decision.

  16. 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

  17. Moving epithelia: Tracking the fate of mammalian limbal epithelial stem cells.

    Science.gov (United States)

    Di Girolamo, Nick

    2015-09-01

    Lineage tracing allows the destiny of a stem cell (SC) and its progeny to be followed through time. In order to track their long-term fate, SC must be permanently marked to discern their distribution, division, displacement and differentiation. This information is essential for unravelling the mysteries that govern their replenishing activity while they remain anchored within their niche microenvironment. Modern-day lineage tracing uses inducible genetic recombination to illuminate cells within embryonic, newborn and adult tissues, and the advent of powerful high-resolution microscopy has enabled the behaviour of labelled cells to be monitored in real-time in a living organism. The simple structural organization of the mammalian cornea, including its accessibility and transparency, renders it the ideal tissue to study SC fate using lineage tracing assisted by non-invasive intravital microscopy. Despite more than a century of research devoted to understanding how this tissue is maintained and repaired, many limitations and controversies continue to plague the field, including uncertainties about the specificity of current SC markers, the number of SC within the cornea, their mode of division, their location, and importantly the signals that dictate cell migration. This communication will highlight historical discoveries as well as recent developments in the corneal SC field; more specifically how the progeny of these cells are mobilised to replenish this dynamic tissue during steady-state, disease and transplantation. Also discussed is how insights gleaned from animal studies can be used to advance our knowledge of the fundamental mechanisms that govern modelling and remodelling of the human cornea in health and disease.

  18. Expression of an activated rasD gene changes cell fate decisions during Dictyostelium development.

    Science.gov (United States)

    Louis, S A; Spiegelman, G B; Weeks, G

    1997-02-01

    It has been previously demonstrated that the expression of an activated rasD gene in wild-type Dictyostelium cells results in formation of aggregates with multitips, instead of the normal single tips, and a block in further development. In an attempt to better understand the role of activated RasD development, we examined cell-type-specific gene expression in a strain stably expressing high levels of RasD[G12T]. We found that the expression of prestalk cell-specific genes ecmA and tagB was markedly enhanced, whereas the expression of the prespore cell-specific gene cotC was reduced to very low levels. When the fate of cells in the multitipped aggregate was monitored with an ecmA/lacZ fusion, it appeared that most of the cells eventually adopted prestalk gene expression characteristics. When mixtures of the [G12T]rasD cells and Ax3 cells were induced to differentiate, chimeric pseudoplasmodia were not formed. Thus, although the [G12T]rasD transformant had a marked propensity to form prestalk cells, it could not supply the prestalk cell population when mixed with wild-type cells. Both stalk and spore cell formation occurred in low cell density monolayers of the [G12T]rasD strain, suggesting that at least part of the inhibition of stalk and spore formation during multicellular development involved inhibitory cell interactions within the cell mass. Models for the possible role of rasD in development are discussed.

  19. 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.

  20. 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.

  1. 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. PMID:27200031

  2. [Fate and balance of bulk blending controlled release fertilizer nitrogen under continuous cropping of mustard].

    Science.gov (United States)

    Zhang, Pan-Pan; Fan, Xiao-Lin

    2012-10-01

    Under the conditions of applying water soluble fertilizer and its bulk blending with controlled release fertilizer (BB-CRF), and by using micro-lysimeter, this paper quantitatively studied the nitrogen (N) uptake by mustard, the soil N losses from N2O emission, leaching and others, and the N residual in soil in three rotations of continuously cropped mustard. In the treatment of BB-CRF with 25% of controlled release nitrogen, the N uptake by mustard increased with rotations, and the yield by the end of the experiment was significantly higher than that in the treatment of water soluble fertilizer. The cumulated N2O emission loss and the N leaching loss were obviously higher in treatment water soluble fertilizer than in treatment BB-CRF. NO3(-)-N was the primary form of N in the leachate. In relative to water soluble fertilizer, BB-CRF altered the fates of fertilizer nitrogen, i.e., the N uptake by mustard and the N residual in soil increased by 75.4% and 76.0%, and the N leaching loss and other apparent N losses decreased by 27.1% and 66.3%, respectively. The application of BB-CRF could be an effective way to reduce the various losses of fertilizer N while increase the fertilizer N use efficiency, and the controlled release fertilizer is the environmentally friendly fertilizer with the property of high N use efficiency.

  3. Expression of activated Ras during Dictyostelium development alters cell localization and changes cell fate.

    Science.gov (United States)

    Jaffer, Z M; Khosla, M; Spiegelman, G B; Weeks, G

    2001-03-01

    There is now a body of evidence to indicate that Ras proteins play important roles in development. Dictyostelium expresses several ras genes and each appears to perform a distinct function. Previous data had indicated that the overexpression of an activated form of the major developmentally regulated gene, rasD, caused a major aberration in morphogenesis and cell type determination. We now show that the developmental expression of an activated rasG gene under the control of the rasD promoter causes a similar defect. Our results indicate that the expression of activated rasG in prespore cells results in their transdifferentiation into prestalk cells, whereas activated rasG expression in prestalk causes gross mislocalization of the prestalk cell populations.

  4. 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.

  5. Forced expression of Hnf1b/Foxa3 promotes hepatic fate of embryonic stem cells.

    Science.gov (United States)

    Yahoo, Neda; Pournasr, Behshad; Rostamzadeh, Jalal; Hakhamaneshi, Mohammad Saeed; Ebadifar, Asghar; Fathi, Fardin; Baharvand, Hossein

    2016-05-20

    Embryonic stem (ES) cell-derived hepatocytes have the potential to be used for basic research, regenerative medicine, and drug discovery. Recent reports demonstrated that in addition to conventional differentiation inducers such as chemical compounds and cytokines, overexpression of lineage-specific transcription factors could induce ES cells to differentiate to a hepatic fate. Here, we hypothesized that lentivirus-mediated inducible expression of hepatic lineage transcription factors could enhance mouse ES cells to hepatocyte-like cells. We screened the effects of candidate transcription factors Hnf1b, Hnf1a, Hnf4a, Foxa1, Foxa3 and Hex, and determined that the combination of Hnf1b/Foxa3 promoted expression of several hepatic lineage-specific markers and proteins, in addition to glycogen storage, ICG uptake, and secretion of albumin and urea. The differentiated cells were engraftable and expressed albumin when transplanted into a carbon tetrachloride-injured mouse model. These results demonstrated the crucial role of Hnf1b and Foxa3 in hepatogenesis in vitro and provided a valuable tool for the efficient differentiation of HLCs from ES cells.

  6. Matrix stiffness determines the fate of nucleus pulposus-derived stem cells.

    Science.gov (United States)

    Navaro, Yosi; Bleich-Kimelman, Nadav; Hazanov, Lena; Mironi-Harpaz, Iris; Shachaf, Yonatan; Garty, Shai; Smith, Yoav; Pelled, Gadi; Gazit, Dan; Seliktar, Dror; Gazit, Zulma

    2015-05-01

    Intervertebral disc (IVD) degeneration and consequent low-back pain present a major medical challenge. Nucleus pulposus-derived stem cells (NP-SCs) may lead to a novel therapy for this severe disease. It was recently shown that survival and function of mature NP cells are regulated in part by tissue stiffness. We hypothesized that modification of matrix stiffness will influence the ability of cultured NP-SCs to proliferate, survive, and differentiate into mature NP cells. NP-SCs were subcultured in three-dimensional matrices of varying degrees of stiffness as measured by the material's shear storage modulus. Cell survival, activity, and rate of differentiation toward the chondrogenic or osteogenic lineage were analyzed. NP-SCs were found to proliferate and differentiate in all matrices, irrespective of matrix stiffness. However, matrices with a low shear storage modulus (G' = 1 kPa) promoted significantly more proliferation and chondrogenic differentiation, whereas matrices with a high modulus (G' = 2 kPa) promoted osteogenic differentiation. Imaging performed via confocal and scanning electron microscopes validated cell survival and highlighted stiffness-dependent cell-matrix interactions. These results underscore the effect of the matrix modulus on the fate of NP-SCs. This research may facilitate elucidation of the complex cross-talk between NP-SCs and their surrounding matrix in healthy as well as pathological conditions.

  7. 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.

  8. Multiplex assay for live-cell monitoring of cellular fates of amyloid-β precursor protein (APP.

    Directory of Open Access Journals (Sweden)

    Maria Merezhko

    Full Text Available Amyloid-β precursor protein (APP plays a central role in pathogenesis of Alzheimer's disease. APP has a short half-life and undergoes complex proteolytic processing that is highly responsive to various stimuli such as changes in cellular lipid or energy homeostasis. Cellular trafficking of APP is controlled by its large protein interactome, including dozens of cytosolic adaptor proteins, and also by interactions with lipids. Currently, cellular regulation of APP is mostly studied based on appearance of APP-derived proteolytic fragments to conditioned media and cellular extracts. Here, we have developed a novel live-cell assay system based on several indirect measures that reflect altered APP trafficking and processing in cells. Protein-fragment complementation assay technology for detection of APP-BACE1 protein-protein interaction forms the core of the new assay. In a multiplex form, the assay can measure four endpoints: total cellular APP level, total secreted sAPP level in media, APP-BACE1 interaction in cells and in exosomes released by the cells. Functional validation of the assay with pharmacological and genetic tools revealed distinct patterns of cellular fates of APP, with immediate mechanistic implications. This new technology will facilitate functional genomics studies of late-onset Alzheimer's disease, drug discovery efforts targeting APP and characterization of the physiological functions of APP and its proteolytic fragments.

  9. 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.

  10. Duration of culture and sonic hedgehog signaling differentially specify PV versus SST cortical interneuron fates from embryonic stem cells.

    Science.gov (United States)

    Tyson, Jennifer A; Goldberg, Ethan M; Maroof, Asif M; Xu, Qing; Petros, Timothy J; Anderson, Stewart A

    2015-04-01

    Medial ganglionic eminence (MGE)-derived GABAergic cortical interneurons (cINs) consist of multiple subtypes that are involved in many cortical functions. They also have a remarkable capacity to migrate, survive and integrate into cortical circuitry after transplantation into postnatal cortex. These features have engendered considerable interest in generating distinct subgroups of interneurons from pluripotent stem cells (PSCs) for the study of interneuron fate and function, and for the development of cell-based therapies. Although advances have been made, the capacity to generate highly enriched pools of subgroup fate-committed interneuron progenitors from PSCs has remained elusive. Previous studies have suggested that the two main MGE-derived interneuron subgroups--those expressing somatostatin (SST) and those expressing parvalbumin (PV)--are specified in the MGE from Nkx2.1-expressing progenitors at higher or lower levels of sonic hedgehog (Shh) signaling, respectively. To further explore the role of Shh and other factors in cIN fate determination, we generated a reporter line such that Nkx2.1-expressing progenitors express mCherry and postmitotic Lhx6-expressing MGE-derived interneurons express GFP. Manipulations of Shh exposure and time in culture influenced the subgroup fates of ESC-derived interneurons. Exposure to higher Shh levels, and collecting GFP-expressing precursors at 12 days in culture, resulted in the strongest enrichment for SST interneurons over those expressing PV, whereas the strongest enrichment for PV interneurons was produced by lower Shh and by collecting mCherry-expressing cells after 17 days in culture. These findings confirm that fate determination of cIN subgroups is crucially influenced by Shh signaling, and provide a system for the further study of interneuron fate and function.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Dynamical modeling of the cell cycle and cell fate emergence in Caulobacter crescentus.

    Directory of Open Access Journals (Sweden)

    César Quiñones-Valles

    Full Text Available The division of Caulobacter crescentus, a model organism for studying cell cycle and differentiation in bacteria, generates two cell types: swarmer and stalked. To complete its cycle, C. crescentus must first differentiate from the swarmer to the stalked phenotype. An important regulator involved in this process is CtrA, which operates in a gene regulatory network and coordinates many of the interactions associated to the generation of cellular asymmetry. Gaining insight into how such a differentiation phenomenon arises and how network components interact to bring about cellular behavior and function demands mathematical models and simulations. In this work, we present a dynamical model based on a generalization of the Boolean abstraction of gene expression for a minimal network controlling the cell cycle and asymmetric cell division in C. crescentus. This network was constructed from data obtained from an exhaustive search in the literature. The results of the simulations based on our model show a cyclic attractor whose configurations can be made to correspond with the current knowledge of the activity of the regulators participating in the gene network during the cell cycle. Additionally, we found two point attractors that can be interpreted in terms of the network configurations directing the two cell types. The entire network is shown to be operating close to the critical regime, which means that it is robust enough to perturbations on dynamics of the network, but adaptable to environmental changes.

  13. Dynamical modeling of the cell cycle and cell fate emergence in Caulobacter crescentus.

    Science.gov (United States)

    Quiñones-Valles, César; Sánchez-Osorio, Ismael; Martínez-Antonio, Agustino

    2014-01-01

    The division of Caulobacter crescentus, a model organism for studying cell cycle and differentiation in bacteria, generates two cell types: swarmer and stalked. To complete its cycle, C. crescentus must first differentiate from the swarmer to the stalked phenotype. An important regulator involved in this process is CtrA, which operates in a gene regulatory network and coordinates many of the interactions associated to the generation of cellular asymmetry. Gaining insight into how such a differentiation phenomenon arises and how network components interact to bring about cellular behavior and function demands mathematical models and simulations. In this work, we present a dynamical model based on a generalization of the Boolean abstraction of gene expression for a minimal network controlling the cell cycle and asymmetric cell division in C. crescentus. This network was constructed from data obtained from an exhaustive search in the literature. The results of the simulations based on our model show a cyclic attractor whose configurations can be made to correspond with the current knowledge of the activity of the regulators participating in the gene network during the cell cycle. Additionally, we found two point attractors that can be interpreted in terms of the network configurations directing the two cell types. The entire network is shown to be operating close to the critical regime, which means that it is robust enough to perturbations on dynamics of the network, but adaptable to environmental changes.

  14. 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.; 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, Drou

  15. Revealing the fate of cell surface human P-glycoprotein (ABCB1): The Lysosomal Degradation Pathway

    Science.gov (United States)

    Katayama, Kazuhiro; Kapoor, Khyati; Ohnuma, Shinobu; Patel, Atish; Swaim, William; Ambudkar, Indu S.; Ambudkar, Suresh V.

    2015-01-01

    P-glycoprotein (P-gp) transports a variety of chemically dissimilar amphipathic compounds including anticancer drugs. Although mechanisms of P-gp drug transport are widely studied, the pathways involving its internalization are poorly understood. The present study is aimed at elucidating the pathways involved in degradation of cell surface P-gp. The fate of P-gp at the cell surface was determined by biotinylating cell surface proteins followed by flow cytometry and Western blotting. Our data shows that the half-life of endogenously expressed P-gp is 26.7 ± 1.1 h in human colorectal cancer HCT-15 cells. Treatment of cells with Bafilomycin A1 (BafA1) a vacuolar H+ ATPase inhibitor increased the half-life of P-gp at the cell surface to 36.1± 0.5 h. Interestingly, treatment with the proteasomal inhibitors MG132, MG115 or lactacystin alone did not alter the half-life of the protein. When cells were treated with both lysosomal and proteasomal inhibitors (BafA1 and MG132), the half-life was further prolonged to 39-50 h. Functional assays done with rhodamine 123 or calcein-AM, fluorescent substrates of P-gp, indicated that the transport function of P-gp was not affected by either biotinylation or treatment with BafA1 or proteasomal inhibitors. Immunofluorescence studies done with the antibody against lysosomal marker LAMP1 and the P-gp-specific antibody UIC2 in permeabilized cells indicated that intracellular P-gp is primarily localized in the lysosomal compartment. Our results suggest that the lysosomal degradation system could be targeted to increase the sensitivity of P-gp expressing cancer cells towards chemotherapeutic drugs. PMID:26057472

  16. Revealing the fate of cell surface human P-glycoprotein (ABCB1): The lysosomal degradation pathway.

    Science.gov (United States)

    Katayama, Kazuhiro; Kapoor, Khyati; Ohnuma, Shinobu; Patel, Atish; Swaim, William; Ambudkar, Indu S; Ambudkar, Suresh V

    2015-10-01

    P-glycoprotein (P-gp) transports a variety of chemically dissimilar amphipathic compounds including anticancer drugs. Although mechanisms of P-gp drug transport are widely studied, the pathways involving its internalization are poorly understood. The present study is aimed at elucidating the pathways involved in degradation of cell surface P-gp. The fate of P-gp at the cell surface was determined by biotinylating cell surface proteins followed by flow cytometry and Western blotting. Our data shows that the half-life of endogenously expressed P-gp is 26.7±1.1 h in human colorectal cancer HCT-15 cells. Treatment of cells with Bafilomycin A1 (BafA1) a vacuolar H+ ATPase inhibitor increased the half-life of P-gp at the cell surface to 36.1±0.5 h. Interestingly, treatment with the proteasomal inhibitors MG132, MG115 or lactacystin alone did not alter the half-life of the protein. When cells were treated with both lysosomal and proteasomal inhibitors (BafA1 and MG132), the half-life was further prolonged to 39-50 h. Functional assays done with rhodamine 123 or calcein-AM, fluorescent substrates of P-gp, indicated that the transport function of P-gp was not affected by either biotinylation or treatment with BafA1 or proteasomal inhibitors. Immunofluorescence studies done with the antibody against lysosomal marker LAMP1 and the P-gp-specific antibody UIC2 in permeabilized cells indicated that intracellular P-gp is primarily localized in the lysosomal compartment. Our results suggest that the lysosomal degradation system could be targeted to increase the sensitivity of P-gp- expressing cancer cells towards chemotherapeutic drugs.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Cell control report

    CERN Document Server

    2013-01-01

    Please note this is a Short Discount publication. This extensive report provides an essential overview of cells and their use as factory automation building blocks. The following issues are discussed in depth: Cell integration Cell software and standards Future technologies applied to cells Plus Cell control applications including: - rotary parts manufacturing - diesel engine component development - general cell control development at the General Electric Corporation - a vendor list.

  20. Zebrafish eve1 regulates the lateral and ventral fates of mesodermal progenitor cells at the onset of gastrulation.

    Science.gov (United States)

    Seebald, Jamie L; Szeto, Daniel P

    2011-01-01

    Zebrafish eve1, a member of the even-skipped related gene family, is expressed initially in the animal pole of late blastula embryo and subsequently restricted to the ventral mesoderm of the gastrula embryo under the signaling control of bone morphogenetic protein (Bmp). Overexpression of eve1 in embryos results in similar ventralized phenotypes to that seen in embryos overexpressing Bmp, suggesting that Eve1 acts downstream of the Bmp signaling pathway to regulate the fate of mesodermal progenitor cells (MPCs). How eve1 functions in the normal development of MPCs is unknown. Using overexpression of a chimeric protein of Eve1 fused to the Gal4 activation domain and gene-knockdown approaches, we investigated the role of eve1 in MPC development of zebrafish embryos at early gastrulation. We find that Eve1 functions as a transcriptional repressor and is required for normal MPC development. The role of eve1 in MPCs requires the redundant and cooperative functions of Bmp-activated downstream homeobox genes, ved, vent and vox. Inhibition of eve1, ved, vent and vox in double and triple combinations results in dorsalized phenotypes. Furthermore, specific inhibition of eve1 and ved causes the expression of an ectopic patch of the brachyury ortholog no tail and leads to the formation of an ectopic tail. Our data show that Eve1 functions together with Ved, Vent and Vox in a transcriptional network to prevent the spread of anti-Bmp gene activity from the dorsal side, leading to the establishment of the Bmp gradient activity along the dorsoventral axis to induce distinct transcriptional outputs in MPCs to maintain the lateral and ventral MPC fates during gastrulation.

  1. Signaling regulating inner ear development: cell fate determination, patterning, morphogenesis, and defects.

    Science.gov (United States)

    Nakajima, Yuji

    2015-02-01

    The membranous labyrinth of the inner ear is a highly complex organ that detects sound and balance. Developmental defects in the inner ear cause congenital hearing loss and balance disorders. The membranous labyrinth consists of three semicircular ducts, the utricle, saccule, and endolymphatic ducts, and the cochlear duct. These complex structures develop from the simple otic placode, which is established in the cranial ectoderm adjacent to the neural crest at the level of the hindbrain at the early neurula stage. During development, the otic placode invaginates to form the otic vesicle, which subsequently gives rise to neurons for the vestibulocochlear ganglion, the non-sensory and sensory epithelia of the membranous labyrinth that includes three ampullary crests, two maculae, and the organ of Corti. Combined paracrine and autocrine signals including fibroblast growth factor, Wnt, retinoic acid, hedgehog, and bone morphogenetic protein regulate fate determination, axis formation, and morphogenesis in the developing inner ear. Juxtacrine signals mediated by Notch pathways play a role in establishing the sensory epithelium, which consists of mechanosensory hair cells and supporting cells. The highly differentiated organ of Corti, which consists of uniformly oriented inner/outer hair cells and specific supporting cells, develops during fetal development. Developmental alterations/arrest causes congenital malformations in the inner ear in a spatiotemporal-restricted manner. A clearer understanding of the mechanisms underlying inner ear development is important not only for the management of patients with congenital inner ear malformations, but also for the development of regenerative therapy for impaired function.

  2. Ligand-induced fate of embryonic species in the shape-controlled synthesis of rhodium nanoparticles.

    Science.gov (United States)

    Biacchi, Adam J; Schaak, Raymond E

    2015-02-24

    The shapes of noble metal nanoparticles directly impact their properties and applications, including in catalysis and plasmonics, and it is therefore important to understand how multiple distinct morphologies can be controllably synthesized. Solution routes offer powerful capabilities for shape-controlled nanoparticle synthesis, but the earliest stages of the reaction are difficult to interrogate experimentally and much remains unknown about how metal nanoparticle morphologies emerge and evolve. Here, we use a well-established polyol process to synthesize uniform rhodium nanoparticle cubes, icosahedra, and triangular plates using bromide, trifluoroacetate, and chloride ligands, respectively. In all of these systems, we identified rhodium clusters with diameters of 1-2 nm that form early in the reactions. The colloidally stable metal cluster intermediates served as a stock solution of embryonic species that could be transformed predictably into each type of nanoparticle morphology. The anionic ligands that were added to the embryonic species determined their eventual fate, e.g., the morphologies into which they would ultimately evolve. Extensive high-resolution transmission electron microscopy experiments revealed that the growth pathway-monomer addition, coalescence, or a combination of the two-was different for each of the morphologies, and was likely controlled by the interactions of each specific anionic adsorbate with the embryonic species. Similar phenomena were observed for related palladium and platinum nanoparticle systems. These studies provide important insights into how noble metal nanoparticles nucleate, the pathways by which they grow into several distinct morphologies, and the imperative role of the anonic ligand in controlling which route predominates in a particular system.

  3. Tumor Suppressor Lzap Suppresses Wnt/β-Catenin Signaling to Promote Zebrafish Embryonic Ventral Cell Fates via the Suppression of Inhibitory Phosphorylation of Glycogen Synthase Kinase 3*

    Science.gov (United States)

    Lin, Kun-Yang; Kao, Shih-Han; Lai, Chun-Ming; Chen, Ciao-Ting; Wu, Chang-Yi; Hsu, Hwei-Jan; Wang, Wen-Der

    2015-01-01

    Wnt/β-catenin signaling controls various cell fates in metazoan development, and its dysregulation is often associated with cancer formation. However, regulations of this signaling pathway are not completely understood. Here, we report that Lzap, a tumor suppressor, controls nuclear translocation of β-catenin. In zebrafish embryos disruption of lzap increases the expression of chordin (chd), which encodes a bone morphogenetic protein (BMP) antagonist that is localized in prospective dorsal cells and promotes dorsal fates. Consistently, lzap-deficient embryos with attenuated BMP signaling are dorsalized, which can be rescued by overexpression of zebrafish lzap or bmp2b or human LZAP. The expansion of chd expression in embryos lacking lzap is due to the accumulation of nuclear β-catenin in ventral cells, in which β-catenin is usually degraded. Furthermore, the activity of GSK3, a master regulator of β-catenin degradation, is suppressed in lzap-deficient embryos via inhibitory phosphorylation. Finally, we also report that a similar regulatory axis is also likely to be present in a human tongue carcinoma cell line, SAS. Our results reveal that Lzap is a novel regulator of GSK3 for the maintenance of ventral cell properties and may prevent carcinogenesis via the regulation of β-catenin degradation. PMID:26475862

  4. Data integration for identification of important transcription factors of STAT6-mediated cell fate decisions.

    Science.gov (United States)

    Jargosch, M; Kröger, S; Gralinska, E; Klotz, U; Fang, Z; Chen, W; Leser, U; Selbig, J; Groth, D; Baumgrass, R

    2016-06-24

    Data integration has become a useful strategy for uncovering new insights into complex biological networks. We studied whether this approach can help to delineate the signal transducer and activator of transcription 6 (STAT6)-mediated transcriptional network driving T helper (Th) 2 cell fate decisions. To this end, we performed an integrative analysis of publicly available RNA-seq data of Stat6-knockout mouse studies together with STAT6 ChIP-seq data and our own gene expression time series data during Th2 cell differentiation. We focused on transcription factors (TFs), cytokines, and cytokine receptors and delineated 59 positively and 41 negatively STAT6-regulated genes, which were used to construct a transcriptional network around STAT6. The network illustrates that important and well-known TFs for Th2 cell differentiation are positively regulated by STAT6 and act either as activators for Th2 cells (e.g., Gata3, Atf3, Satb1, Nfil3, Maf, and Pparg) or as suppressors for other Th cell subpopulations such as Th1 (e.g., Ar), Th17 (e.g., Etv6), or iTreg (e.g., Stat3 and Hif1a) cells. Moreover, our approach reveals 11 TFs (e.g., Atf5, Creb3l2, and Asb2) with unknown functions in Th cell differentiation. This fact together with the observed enrichment of asthma risk genes among those regulated by STAT6 underlines the potential value of the data integration strategy used here. Thus, our results clearly support the opinion that data integration is a useful tool to delineate complex physiological processes.

  5. Mercury fate in ageing and melting snow: development and testing of a controlled laboratory system.

    Science.gov (United States)

    Mann, Erin; Meyer, Torsten; Mitchell, Carl P J; Wania, Frank

    2011-10-01

    A snow cover can modify when, to what extent, and in what form atmospherically deposited mercury is released to the underlying surface media and/or back to the atmosphere. Investigations of mercury transport and transformation processes in snow packs are hampered by the difficulty in controlling experimental and melt conditions and due to the huge variability in the composition and physical structure of environmental snow packs. A method was developed that allows the detailed mechanistic investigation of mercury fate in snow that is made, aged and melted under controlled laboratory conditions. A number of control samples established that mercury in indoor air, scavenged during the snow making process, constitutes the dominant source of mercury in the artificial snow. No addition of mercury is required. The amount of mercury in fresh snow was quantitatively (102 and 106% in two experiments) recovered in the dissolved and particulate fractions of the melt water and the vessel head space, confirming a mass balance for mercury and the absence of unquantifiable mercury sources and sinks in the experimental system. In snow made from unmodified tap water, more than half of the mercury present in the snowpack was recovered from the bottom of the snow vessel after all of the snow had melted. Such late elution is indicative of mercury being mostly associated with particles that are filtered by, and retained in, the shrinking snowpack. Addition of salt to the snow-making water at an environmentally realistic pH notably shifted the distribution of mercury in the snowpack from the particulate to the dissolved phase, resulting in more than 60% of the mercury eluting in the dissolved phase of early melt water fractions.

  6. The IgH 3′ regulatory region governs μ chain transcription in mature B lymphocytes and the B cell fate

    Science.gov (United States)

    Saintamand, Alexis; Rouaud, Pauline; Garot, Armand; Saad, Faten; Carrion, Claire; Oblet, Christelle; Cogné, Michel; Pinaud, Eric; Denizot, Yves

    2015-01-01

    We report that the IgH 3′ regulatory region (3′RR) has no role on μ chain transcription and pre-BCR expression in B cell progenitors. In contrast, analysis of heterozygous IgH aΔ3′RR/bwt mice indicated that the 3′RR controls μ chain transcripts in mature splenocytes and impacts membrane IgM density without obvious effect on BCR signals (colocalisation with lipid rafts and phosphorylation of Erk and Akt after BCR crosslinking). Deletion of the 3′RR modulates the B cell fate to less marginal zone B cells. In conclusion, the 3′RR is dispensable for pre-BCR expression and necessary for optimal commitments toward the marginal zone B cell fate. These results reinforce the concept of a dual regulation of the IgH locus transcription and accessibility by 5′ elements at immature B cell stages, and by the 3′RR as early as the resting mature B cell stage and then along further activation and differentiation. PMID:25742787

  7. Quantifying Waddington landscapes and paths of non-adiabatic cell fate decisions for differentiation, reprogramming and transdifferentiation

    Science.gov (United States)

    Li, Chunhe; Wang, Jin

    2013-01-01

    Cellular differentiation, reprogramming and transdifferentiation are determined by underlying gene regulatory networks. Non-adiabatic regulation via slow binding/unbinding to the gene can be important in these cell fate decision-making processes. Based on a stem cell core gene network, we uncovered the stem cell developmental landscape. As the binding/unbinding speed decreases, the landscape topography changes from bistable attractors of stem and differentiated states to more attractors of stem and other different cell states as well as substates. Non-adiabaticity leads to more differentiated cell types and provides a natural explanation for the heterogeneity observed in the experiments. We quantified Waddington landscapes with two possible cell fate decision mechanisms by changing the regulation strength or regulation timescale (non-adiabaticity). Transition rates correlate with landscape topography through barrier heights between different states and quantitatively determine global stability. We found the optimal speeds of these cell fate decision-making processes. We quantified biological paths and predict that differentiation and reprogramming go through an intermediate state (IM1), whereas transdifferentiation goes through another intermediate state (IM2). Some predictions are confirmed by recent experimental studies. PMID:24132204

  8. Genomic DISC1 Disruption in hiPSCs Alters Wnt Signaling and Neural Cell Fate

    Directory of Open Access Journals (Sweden)

    Priya Srikanth

    2015-09-01

    Full Text Available Genetic and clinical association studies have identified disrupted in schizophrenia 1 (DISC1 as a candidate risk gene for major mental illness. DISC1 is interrupted by a balanced chr(1;11 translocation in a Scottish family in which the translocation predisposes to psychiatric disorders. We investigate the consequences of DISC1 interruption in human neural cells using TALENs or CRISPR-Cas9 to target the DISC1 locus. We show that disruption of DISC1 near the site of the translocation results in decreased DISC1 protein levels because of nonsense-mediated decay of long splice variants. This results in an increased level of canonical Wnt signaling in neural progenitor cells and altered expression of fate markers such as Foxg1 and Tbr2. These gene expression changes are rescued by antagonizing Wnt signaling in a critical developmental window, supporting the hypothesis that DISC1-dependent suppression of basal Wnt signaling influences the distribution of cell types generated during cortical development.

  9. Quantifying Cell Fate Decisions for Differentiation and Reprogramming of a Human Stem Cell Network: Landscape and Biological Paths

    Science.gov (United States)

    Li, Chunhe; Wang, Jin

    2013-01-01

    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. PMID:23935477

  10. Amyloid-β alters the DNA methylation status of cell-fate genes in an Alzheimer's disease model.

    Science.gov (United States)

    Taher, Noor; McKenzie, Courtney; Garrett, Rebecca; Baker, Matthew; Fox, Nena; Isaacs, Gary D

    2014-01-01

    Alzheimer's disease (AD) is characterized by neurofibrillary tangles and extracellular amyloid-β plaques (Aβ). Despite ongoing research, some ambiguity remains surrounding the role of Aβ in the pathogenesis of this neurodegenerative disease. While several studies have focused on the mutations associated with AD, our understanding of the epigenetic contributions to the disease remains less clear. To that end, we determined the changes in DNA methylation in differentiated human neurons with and without Aβ treatment. DNA was isolated from neurons treated with Aβ or vehicle, and the two samples were digested with either a methylation-sensitive (HpaII) or a methylation-insensitive (MspI) restriction endonuclease. The fragments were amplified and co-hybridized to a commercial promoter microarray. Data analysis revealed a subset of genomic loci that shows a significant change in DNA methylation following Aβ treatment in comparison to the control group. After mapping these loci to nearby genes, we discovered high enrichment for cell-fate genes that control apoptosis and neuronal differentiation. Finally, we incorporated three of those genes in a possible model suggesting the means by which Aβ contributes to the brain shrinkage and memory loss seen in AD.

  11. Surface Chemistry of Nanoscale Mineralized Collagen Regulates Periodontal Ligament Stem Cell Fate.

    Science.gov (United States)

    Fu, Yu; Liu, Shuai; Cui, Sheng-Jie; Kou, Xiao-Xing; Wang, Xue-Dong; Liu, Xiao-Mo; Sun, Yue; Wang, Gao-Nan; Liu, Yan; Zhou, Yan-Heng

    2016-06-29

    The interplay between stem cells and their extracellular microenvironment is of critical importance to the stem cell-based therapeutics in regenerative medicine. Mineralized collagen is the main component of bone extracellular matrix, but the effect of interfacial properties of mineralized collagen on subsequent cellular behaviors is unclear. This study examined the role of surface chemistry of nanoscale mineralized collagen on human periodontal ligament stem cell (hPDLSC) fate decisions. The intrafibrillarly mineralized collagen (IMC), fabricated by a biomimetic bottom-up approach, showed a bonelike hierarchy with nanohydroxyapatites (HAs) periodically embedded within fibrils. The infrared spectrum of the IMC showed the presence of phosphate, carbonate, amide I and II bands; and infrared mapping displayed uniform and higher spatial distribution of mineralization in the IMC. However, the distribution of the phosphate group differed far from that of the amide I group in the extrafibrillarly mineralized collagen (EMC), in which flowerlike HA clusters randomly depositing around the surface of the fibrils. Moreover, a large quantity of extrafibrillar HAs covered up the C═O stretch and N-H in-plane bend, resulting in substantial reduction of amide I and II bands. Cell experiments demonstrated that the hPDLSCs seeded on the IMC exhibited a highly branched, osteoblast-like polygonal shape with extended pseudopodia and thick stress fiber formation; while cells on the EMC displayed a spindle shape with less branch points and thin actin fibril formation. Furthermore, the biocompatibility of EMC was much lower than that of IMC. Interestingly, even without osteogenic induction, mRNA levels of major osteogenic differentiation genes were highly expressed in the IMC during cultivation time. These data suggest that the IMC with a similar nanotopography and surface chemistry to natural mineralized collagen directs hPDLSCs toward osteoblast differentiation, providing a promising

  12. IRE1α Signaling Pathways Involved in Mammalian Cell Fate Determination

    Directory of Open Access Journals (Sweden)

    Jie Wu

    2016-02-01

    Full Text Available A diverse array of cellular stresses can lead to accumulation of misfolded or unfolded proteins in endoplasmic reticulum (ER, which subsequently elicits ER stress. Inositol-requiring enzyme 1α (IRE1α is the most sensitive of the three unfolded protein response (UPR branches which are triggered to cope with ER stress in mammalian cells. IRE1α signaling is quite context-specific on account of many adaptor and modulator proteins that directly interact with it, including heat shock proteins (HSPs, RING finger protein 13 (RNF13, poly (ADP-ribose polymerase 16 (PARP16, Bax/Bak, and Bax inhibitor-1 (BI-1. The activated IRE1α triggers different downstream pathways depending on the UPRosome formed by distinct modulator proteins. At the initial phase of ER stress, IRE1α-XBP1 axis functions as an adaptive response. While ER stress sustains or intensifies, signals shift to apoptotic responses. Furthermore, IRE1α signaling can be exploited to the development of a wide range of prevalent human diseases, with cancer the most characterized. Here we provide an overview of recent insights into the complex IRE1α signaling network which makes IRE1α an intriguing cell fate switch. Besides, the functional relevance is presented since IRE1α activation also participates in some other physiological processes beyond protein-folding status.

  13. Aurora A Kinase Regulates Mammary Epithelial Cell Fate by Determining Mitotic Spindle Orientation in a Notch-Dependent Manner

    Directory of Open Access Journals (Sweden)

    Joseph L. Regan

    2013-07-01

    Full Text Available Cell fate determination in the progeny of mammary epithelial stem/progenitor cells remains poorly understood. Here, we have examined the role of the mitotic kinase Aurora A (AURKA in regulating the balance between basal and luminal mammary lineages. We find that AURKA is highly expressed in basal stem cells and, to a lesser extent, in luminal progenitors. Wild-type AURKA expression promoted luminal cell fate, but expression of an S155R mutant reduced proliferation, promoted basal fate, and inhibited serial transplantation. The mechanism involved regulation of mitotic spindle orientation by AURKA and the positioning of daughter cells after division. Remarkably, this was NOTCH dependent, as NOTCH inhibitor blocked the effect of wild-type AURKA expression on spindle orientation and instead mimicked the effect of the S155R mutant. These findings directly link AURKA, NOTCH signaling, and mitotic spindle orientation and suggest a mechanism for regulating the balance between luminal and basal lineages in the mammary gland.

  14. The Caenorhabditis elegans PcG-like gene sop-2 regulates the temporal and sexual specificities of cell fates.

    Science.gov (United States)

    Cai, Qingchun; Sun, Yinyan; Huang, Xinxin; Guo, Cong; Zhang, Yuxia; Zhu, Zuoyan; Zhang, Hong

    2008-03-01

    How spatial, temporal, and sexual specific cues are integrated to specify distinct cell fates during multicellular organism development is largely unknown. Here we demonstrate that the Caenorhabditis elegans PcG-like gene sop-2 determines the temporal and sexual specificities of a row of hypodermal seam cells, in addition to specifying their positional identities. Loss-of-function of sop-2 causes premature expression of adult fates at larval stages. sop-2 acts upstream of lin-29 in the heterochronic pathway and genetically interacts with other heterochronic genes in specifying the temporal fates of seam cells at different larval stages. We show that the number of ALG-1-containing P bodies is increased in seam cells in sop-2 mutants. Furthermore, the microRNA-mediated repression of a heterochronic gene reporter is enhanced in sop-2 mutants. Mutations in sop-2 also cause partial hermaphrodite-to-male sexual transformations. The homeotic transformations, heterochronic defects, and sexual transformations can occur concomitantly in sop-2 mutants. In summary, our studies reveal that sop-2 integrates spatial, temporal, and sexual cues during C. elegans development.

  15. 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.

  16. HIPPO pathway members restrict SOX2 to the inner cell mass where it promotes ICM fates in the mouse blastocyst.

    Directory of Open Access Journals (Sweden)

    Eryn Wicklow

    2014-10-01

    Full Text Available Pluripotent epiblast (EPI cells, present in the inner cell mass (ICM of the mouse blastocyst, are progenitors of both embryonic stem (ES cells and the fetus. Discovering how pluripotency genes regulate cell fate decisions in the blastocyst provides a valuable way to understand how pluripotency is normally established. EPI cells are specified by two consecutive cell fate decisions. The first decision segregates ICM from trophectoderm (TE, an extraembryonic cell type. The second decision subdivides ICM into EPI and primitive endoderm (PE, another extraembryonic cell type. Here, we investigate the roles and regulation of the pluripotency gene Sox2 during blastocyst formation. First, we investigate the regulation of Sox2 patterning and show that SOX2 is restricted to ICM progenitors prior to blastocyst formation by members of the HIPPO pathway, independent of CDX2, the TE transcription factor that restricts Oct4 and Nanog to the ICM. Second, we investigate the requirement for Sox2 in cell fate specification during blastocyst formation. We show that neither maternal (M nor zygotic (Z Sox2 is required for blastocyst formation, nor for initial expression of the pluripotency genes Oct4 or Nanog in the ICM. Rather, Z Sox2 initially promotes development of the primitive endoderm (PE non cell-autonomously via FGF4, and then later maintains expression of pluripotency genes in the ICM. The significance of these observations is that 1 ICM and TE genes are spatially patterned in parallel prior to blastocyst formation and 2 both the roles and regulation of Sox2 in the blastocyst are unique compared to other pluripotency factors such as Oct4 or Nanog.

  17. Yes-associated protein in the liver: Regulation of hepatic development, repair, cell fate determination and tumorigenesis.

    Science.gov (United States)

    Nguyen, Quy; Anders, Robert A; Alpini, Gianfranco; Bai, Haibo

    2015-10-01

    The liver is a vital organ that plays a major role in many bodily functions from protein production and blood clotting to cholesterol, glucose and iron metabolism and nutrition storage. Maintenance of liver homeostasis is critical for these essential bodily functions and disruption of liver homeostasis causes various kinds of liver diseases, some of which have high mortality rate. Recent research advances of the Hippo signalling pathway have revealed its nuclear effector, Yes-associated protein, as an important regulator of liver development, repair, cell fate determination and tumorigenesis. Therefore, a precise control of Yes-associated protein activity is critical for the maintenance of liver homeostasis. This review is going to summarize the discoveries on how the manipulation of Yes-associated protein activity affects liver homeostasis and induces liver diseases and the regulatory mechanisms that determine the Yes-associated protein activity in the liver. Finally, we will discuss the potential of targeting Yes-associated protein as therapeutic strategies in liver diseases.

  18. Expression of zebrafish GATA 3 (gta3) during gastrulation and neurulation suggests a role in the specification of cell fate.

    Science.gov (United States)

    Neave, B; Rodaway, A; Wilson, S W; Patient, R; Holder, N

    1995-06-01

    In order to understand the role of the transcription factor GATA 3 in vertebrate development, we have examined its expression and some aspects of its regulation during gastrulation and neurulation in the zebrafish. The complete coding sequence of the cDNA encoding the zebrafish GATA 3 homologue, termed gta3, is described. Analysis of expression patterns by in situ hybridisation shows the gene to be expressed during gastrulation in the ventral region of the embryo which includes tissue fated to form the non-neural ectoderm. By the end of gastrulation, there is a clear border to the gta3 expression domain that is close to the edge of the neural plate. Subsequently, gta3 expresses in the pronephric duct and in defined regions of the central nervous system which include specific cells in each segment of the spinal cord and nuclei in the brain. Double labelling embryos with a probe for gta3 and antibodies which identify differentiated neurons suggest that gta3 is dynamically expressed during the early differentiation phase of a subset of neurons but not in the terminal phase. Analysis of gta3 expression in dorsalised embryos and in cyc and spt mutant embryos indicates that the neural expression of the gene is subject to control by signals from the mesoderm, including both the notochord and the somites, which influence the segmental organisation of expression in the spinal cord.

  19. Hydrographic controls on marine organic matter fate and microbial diversity in the western Irish Sea

    Science.gov (United States)

    O'Reilly, Shane; Szpak, Michal; Monteys, Xavier; Flanagan, Paul; Allen, Christopher; Kelleher, Brian

    2014-05-01

    Cycling of organic matter (OM) is the key biological process in the marine environment1 and knowledge of the sources and the reactivity of OM, in addition to factors controlling its distribution in estuarine, coastal and shelf sediments are of key importance for understanding global biogeochemical cycles2. With recent advances in cultivation-independent molecular approaches to microbial ecology, the key role of prokaryotes in global biogeochemical cycling in marine ecosystems has been emphasised3,4. However, spatial studies combining the distribution and fate of OM with microbial community abundance and diversity remain rare. Here, a combined spatial lipid biomarker and 16S rRNA tagged pyrosequencing study was conducted in surface sediments and particulate matter across hydrographically distinct zones associated with the seasonal western Irish Sea gyre. The aim was to assess the spatial variation of, and factors controlling, marine organic cycling and sedimentary microbial communities across these distinct zones. The distribution of phospholipid fatty acids, source-specific sterols, wax esters and C25 highly branched isoprenoids indicate that diatoms, dinoflagellates and green algae were the major contributors of marine organic matter, while the distribution of cholesterol, wax esters and C20 and C22 polyunsaturated fatty acids have highlighted the importance of copepod grazing for mineralizing organic matter in the water column5. This marine OM production and mineralisation was greatest in well-mixed waters compared to offshore stratified waters. Lipid analysis and 16S rRNA PCR-DGGE profiling also suggests that sedimentary bacterial abundance increases while community diversity decreases in offshore stratified waters. The major bacterial classes are the Deltaproteobacteria, Clostridia, Flavobacteriia, Gammaproteobactera and Bacteroiidia. At the family/genus level most groups appear to be associated with organoheterotrophic processing of sedimentary OM, ranging

  20. Dynamics of defense responses and cell fate change during Arabidopsis-Pseudomonas syringae interactions.

    Directory of Open Access Journals (Sweden)

    Safae Hamdoun

    picture of dynamic changes of defense phenotypes and cell fate determination during Arabidopsis-P. syringae interactions, contributing to a better understanding of plant defense mechanisms.

  1. Cell Control Engineering

    DEFF Research Database (Denmark)

    Lynggaard, Hans Jørgen Birk; Alting, Leo

    1996-01-01

    The engineering process of creating cell control systems is described, and a Cell Control Engineering (CCE) concept is defined. The purpose is to assist people, representing different disciplines in the organisation, to implement cell controllers by addressing the complexity of having many systems...... in physically and logically different and changing manufacturing environments. The defined CCE concept combines state-of-the-art of commercially available enabling technologies for automation system software development, generic cell control models and guidelines for the complete engineering process....... It facilitates the understanding of the task and structure of cell controllers and uses this knowledge directly in the implementation of the system. By applying generic models CCE facilitates reuse of software components and maintenance of applications. In many enterprises, software makes up an increasing part...

  2. Defined spatiotemporal features of RAS-ERK signals dictate cell fate in MCF-7 mammary epithelial cells

    Science.gov (United States)

    Herrero, Ana; Casar, Berta; Colón-Bolea, Paula; Agudo-Ibáñez, Lorena; Crespo, Piero

    2016-01-01

    Signals conveyed through the RAS-ERK pathway are essential for the determination of cell fate. It is well established that signal variability is achieved in the different microenvironments in which signals unfold. It is also known that signal duration is critical for decisions concerning cell commitment. However, it is unclear how RAS-ERK signals integrate time and space in order to elicit a given biological response. To investigate this, we used MCF-7 cells, in which EGF-induced transient ERK activation triggers proliferation, whereas sustained ERK activation in response to heregulin leads to adipocytic differentiation. We found that both proliferative and differentiating signals emanate exclusively from plasma membrane–disordered microdomains. Of interest, the EGF signal can be transformed into a differentiating stimulus by HRAS overexpression, which prolongs ERK activation, but only if HRAS localizes at disordered membrane. On the other hand, HRAS signals emanating from the Golgi complex induce apoptosis and can prevent heregulin-induced differentiation. Our results indicate that within the same cellular context, RAS can exert different, even antagonistic, effects, depending on its sublocalization. Thus cell destiny is defined by the ability of a stimulus to activate RAS at the appropriate sublocalization for an adequate period while avoiding switching on opposing RAS signals. PMID:27099370

  3. Gene pair signatures in cell type transcriptomes reveal lineage control

    Science.gov (United States)

    Heinäniemi, Merja; Nykter, Matti; Kramer, Roger; Wienecke-Baldacchino, Anke; Sinkkonen, Lasse; Zhou, Joseph Xu; Kreisberg, Richard; Kauffman, Stuart A.; Huang, Sui; Shmulevich, Ilya

    2013-01-01

    The distinct cell types of multicellular organisms arise due to constraints imposed by gene regulatory networks on the collective change of gene expression across the genome, creating self-stabilizing expression states, or attractors. We compiled a resource of curated human expression data comprising 166 cell types and 2,602 transcription regulating genes and developed a data driven method built around the concept of expression reversal defined at the level of gene pairs, such as those participating in toggle switch circuits. This approach allows us to organize the cell types into their ontogenetic lineage-relationships and to reflect regulatory relationships among genes that explain their ability to function as determinants of cell fate. We show that this method identifies genes belonging to regulatory circuits that control neuronal fate, pluripotency and blood cell differentiation, thus offering a novel large-scale perspective on lineage specification. PMID:23603899

  4. Bistable cell fate specification as a result of stochastic fluctuations and collective spatial cell behaviour.

    Directory of Open Access Journals (Sweden)

    Daniel Stockholm

    Full Text Available BACKGROUND: In culture, isogenic mammalian cells typically display enduring phenotypic heterogeneity that arises from fluctuations of gene expression and other intracellular processes. This diversity is not just simple noise but has biological relevance by generating plasticity. Noise driven plasticity was suggested to be a stem cell-specific feature. RESULTS: Here we show that the phenotypes of proliferating tissue progenitor cells such as primary mononuclear muscle cells can also spontaneously fluctuate between different states characterized by the either high or low expression of the muscle-specific cell surface molecule CD56 and by the corresponding high or low capacity to form myotubes. Although this capacity is a cell-intrinsic property, the cells switch their phenotype under the constraints imposed by the highly heterogeneous microenvironment created by their own collective movement. The resulting heterogeneous cell population is characterized by a dynamic equilibrium between "high CD56" and "low CD56" phenotype cells with distinct spatial distribution. Computer simulations reveal that this complex dynamic is consistent with a context-dependent noise driven bistable model where local microenvironment acts on the cellular state by encouraging the cell to fluctuate between the phenotypes until the low noise state is found. CONCLUSIONS: These observations suggest that phenotypic fluctuations may be a general feature of any non-terminally differentiated cell. The cellular microenvironment created by the cells themselves contributes actively and continuously to the generation of fluctuations depending on their phenotype. As a result, the cell phenotype is determined by the joint action of the cell-intrinsic fluctuations and by collective cell-to-cell interactions.

  5. REX-1 expression and p38 MAPK activation status can determine proliferation/differentiation fates in human mesenchymal stem cells.

    Directory of Open Access Journals (Sweden)

    Dilli Ram Bhandari

    Full Text Available BACKGROUND: REX1/ZFP42 is a well-known embryonic stem cell (ESC marker. However, the role of REX1, itself, is relatively unknown because the function of REX1 has only been reported in the differentiation of ESCs via STAT signaling pathways. Human mesenchymal stem cells (hMSCs isolated from young tissues and cancer cells express REX1. METHODOLOGY/PRINCIPAL FINDING: Human umbilical cord blood-derived MSCs (hUCB-MSCs and adipose tissue-derived MSCs (hAD-MSCs strongly express REX1 and have a lower activation status of p38 MAPK, but bone marrow-derived MSCs (hBM-MSCs have weak REX1 expression and higher activation of p38 MAPK. These results indicated that REX1 expression in hMSCs was positively correlated with proliferation rates but inversely correlated with the phosphorylation of p38 MAPK. In hUCB-MSCs, the roles of REX1 and p38 MAPK were investigated, and a knockdown study was performed using a lentiviral vector-based small hairpin RNA (shRNA. After REX1 knockdown, decreased cell proliferation was observed. In REX1 knocked-down hUCB-MSCs, the osteogenic differentiation ability deteriorated, but the adipogenic potential increased or was similar to that observed in the controls. The phosphorylation of p38 MAPK in hUCB-MSCs significantly increased after REX1 knockdown. After p38 MAPK inhibitor treatment, the cell growth in REX1 knocked-down hUCB-MSCs almost recovered, and the suppressed expression levels of CDK2 and CCND1 were also restored. The expression of MKK3, an upstream regulator of p38 MAPK, significantly increased in REX1 knocked-down hUCB-MSCs. The direct binding of REX1 to the MKK3 gene was confirmed by a chromatin immunoprecipitation (ChIP assay. CONCLUSIONS/SIGNIFICANCE: These findings showed that REX1 regulates the proliferation/differentiation of hMSCs through the suppression of p38 MAPK signaling via the direct suppression of MKK3. Therefore, p38 MAPK and REX-1 status can determine the cell fate of adult stem cells (ASCs. These

  6. Transcriptome analysis of soybean leaf abscission identifies transcriptional regulators of organ polarity and cell fate

    Directory of Open Access Journals (Sweden)

    Joonyup eKim

    2016-02-01

    Full Text Available Abscission, organ separation, is a developmental process that is modulated by endogenous and environmental factors. To better understand the molecular events underlying the progression of abscission in soybean, an agriculturally important legume, we performed RNA sequencing (RNA-seq of RNA isolated from the leaf abscission zones (LAZ and petioles (Non-AZ, NAZ after treating stem/petiole explants with ethylene for 0, 12, 24, 48, and 72 h. As expected, expression of several families of cell wall modifying enzymes and many pathogenesis-related (PR genes specifically increased in the LAZ as abscission progressed. Here, we focus on the 5,206 soybean genes we identified as encoding transcription factors (TFs. Of the 5,206 TFs, 1,088 were differentially up- or down-regulated more than 8-fold in the LAZ over time, and, within this group, 188 of the TFs were differentially regulated more than 8-fold in the LAZ relative to the NAZ. These 188 abscission-specific TFs include several TFs containing domains for homeobox, MYB, Zinc finger, bHLH, AP2, NAC, WRKY, YABBY, and auxin-related motifs. To discover the connectivity among the TFs and highlight developmental processes that support organ separation, the 188 abscission-specific TFs were then clustered based on a >4-fold up- or down-regulation in two consecutive time points (i.e., 0 h and 12 h, 12 h and 24 h, 24 h and 48 h, or 48 h and 72 h. By requiring a sustained change in expression over two consecutive time intervals and not just one or several time intervals, we could better tie changes in TFs to a particular process or phase of abscission. The greatest number of TFs clustered into the 0 h and 12 h group. Transcriptional network analysis for these abscission-specific TFs indicated that most of these TFs are known as key determinants in the maintenance of organ polarity, lateral organ growth and cell fate. The abscission-specific expression of these TFs prior to the onset of abscission and their

  7. Transcriptome Analysis of Soybean Leaf Abscission Identifies Transcriptional Regulators of Organ Polarity and Cell Fate.

    Science.gov (United States)

    Kim, Joonyup; Yang, Jinyoung; Yang, Ronghui; Sicher, Richard C; Chang, Caren; Tucker, Mark L

    2016-01-01

    Abscission, organ separation, is a developmental process that is modulated by endogenous and environmental factors. To better understand the molecular events underlying the progression of abscission in soybean, an agriculturally important legume, we performed RNA sequencing (RNA-seq) of RNA isolated from the leaf abscission zones (LAZ) and petioles (Non-AZ, NAZ) after treating stem/petiole explants with ethylene for 0, 12, 24, 48, and 72 h. As expected, expression of several families of cell wall modifying enzymes and many pathogenesis-related (PR) genes specifically increased in the LAZ as abscission progressed. Here, we focus on the 5,206 soybean genes we identified as encoding transcription factors (TFs). Of the 5,206 TFs, 1,088 were differentially up- or down-regulated more than eight-fold in the LAZ over time, and, within this group, 188 of the TFs were differentially regulated more than eight-fold in the LAZ relative to the NAZ. These 188 abscission-specific TFs include several TFs containing domains for homeobox, MYB, Zinc finger, bHLH, AP2, NAC, WRKY, YABBY, and auxin-related motifs. To discover the connectivity among the TFs and highlight developmental processes that support organ separation, the 188 abscission-specific TFs were then clustered based on a >four-fold up- or down-regulation in two consecutive time points (i.e., 0 and 12 h, 12 and 24 h, 24 and 48 h, or 48 and 72 h). By requiring a sustained change in expression over two consecutive time intervals and not just one or several time intervals, we could better tie changes in TFs to a particular process or phase of abscission. The greatest number of TFs clustered into the 0 and 12 h group. Transcriptional network analysis for these abscission-specific TFs indicated that most of these TFs are known as key determinants in the maintenance of organ polarity, lateral organ growth, and cell fate. The abscission-specific expression of these TFs prior to the onset of abscission and their functional

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

    Science.gov (United States)

    Ghosh, Ritabrata; Deshpande, Girish

    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. PMID:28114410

  9. 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.

  10. Influences of LIN-12/Notch and POP-1/TCF on the Robustness of Ventral Uterine Cell Fate Specification in Caenorhabditis elegans Gonadogenesis.

    Science.gov (United States)

    Sallee, Maria D; Aydin, Taner; Greenwald, Iva

    2015-10-19

    The prospective ventral uterus of the hermaphrodite gonad primordium consists of two pairs of sister cells, with each pair consisting of a proximal "α" cell and a distal "β" cell. All four cells initially are competent to become the anchor cell (AC), a unique cell type that acts as the organizer of subsequent uterine and vulval development. However, the β cells soon lose this competence and always become ventral uterine precursor cells (VUs), whereas the α cells maintain their AC competence longer, until lin-12/Notch-mediated interactions between them specify one as the AC and the other as a VU. Here, we investigate this asymmetry in developmental potential and VU fate specification between the α and β sister cells. We find evidence that lin-12 activity contributes to the robustness of βVU fate at elevated temperature, that the Caenorhabditis elegans Notch paralog glp-1 is not functionally redundant with lin-12 in specifying βVU fate, and that the activity of POP-1, the sole C. elegans TCF ortholog, influences βVU fate. We propose a model for how Wnt and LIN-12/Notch signaling together lead to robust specification of the βVU fate.

  11. 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

    implicated in development, but how the regulation of H3K4me3 level controls developmental processes is not fully established. Here, we show that the H3K4 demethylase RBR-2, the unique member of the KDM5 family in C. elegans, acts cell-autonomously and in a catalytic-dependent manner to control vulva...

  12. Asymmetric cell division and its role in cell fate determination in the green alga Tetraselmis indica

    Indian Academy of Sciences (India)

    Mani Arora; Arga Chandrashekar Anil; Karl Burgess; Jane Delany; Ehsan Mesbahi

    2015-12-01

    The prasinophytes (early diverging Chlorophyta), consisting of simple unicellular green algae, occupy a critical position at the base of the green algal tree of life, with some of its representatives viewed as the cell form most similar to the first green alga, the `ancestral green flagellate'. Relatively large-celled unicellular eukaryotic phytoflagellates (such as Tetraselmis and Scherffelia), traditionally placed in Prasinophyceae but now considered as members of Chlorodendrophyceae (core Chlorophyta), have retained some primitive characteristics of prasinophytes. These organisms share several ultrastructural features with the other core chlorophytes (Trebouxiophyceae, Ulvophyceae and Chlorophyceae). However, the role of Chlorodendrophycean algae as the evolutionary link between cellular individuality and cellular cooperation has been largely unstudied. Here, we show that clonal populations of a unicellular chlorophyte, Tetraselmis indica, consist of morphologically and ultrastructurally variant cells which arise through asymmetric cell division. These cells also differ in their physiological properties. The structural and physiological differences in the clonal cell population correlate to a certain extent with the longevity and function of cells.

  13. Mammary gland development: cell fate specification, stem cells and the microenvironment.

    Science.gov (United States)

    Inman, Jamie L; Robertson, Claire; Mott, Joni D; Bissell, Mina J

    2015-03-15

    The development of the mammary gland is unique: the final stages of development occur postnatally at puberty under the influence of hormonal cues. Furthermore, during the life of the female, the mammary gland can undergo many rounds of expansion and proliferation. The mammary gland thus provides an excellent model for studying the 'stem/progenitor' cells that allow this repeated expansion and renewal. In this Review, we provide an overview of the different cell types that constitute the mammary gland, and discuss how these cell types arise and differentiate. As cellular differentiation cannot occur without proper signals, we also describe how the tissue microenvironment influences mammary gland development.

  14. C. elegans EVI1 proto-oncogene, EGL-43, is necessary for Notch-mediated cell fate specification and regulates cell invasion.

    Science.gov (United States)

    Hwang, Byung Joon; Meruelo, Alejandro D; Sternberg, Paul W

    2007-02-01

    During C. elegans development, LIN-12 (Notch) signaling specifies the anchor cell (AC) and ventral uterine precursor cell (VU) fates from two equivalent pre-AC/pre-VU cells in the hermaphrodite gonad. Once specified, the AC induces patterned proliferation of vulva via expression of LIN-3 (EGF) and then invades into the vulval epithelium. Although these cellular processes are essential for the proper organogenesis of vulva and appear to be temporally regulated, the mechanisms that coordinate the processes are not well understood. We computationally identified egl-43 as a gene likely to be expressed in the pre-AC/pre-VU cells and the AC, based on the presence of an enhancer element similar to the one that transcribes lin-3 in the same cells. Genetic epistasis analyses reveal that egl-43 acts downstream of or parallel to lin-12 in AC/VU cell fate specification at an early developmental stage, and functions downstream of fos-1 as well as upstream of zmp-1 and him-4 to regulate AC invasion at a later developmental stage. Characterization of the egl-43 regulatory region suggests that EGL-43 is a direct target of LIN-12 and HLH-2 (E12/47), which is required for the specification of the VU fate during AC/VU specification. EGL-43 also regulates basement membrane breakdown during AC invasion through a FOS-1-responsive regulatory element that drives EGL-43 expression in the AC and VU cells at the later stage. Thus, egl-43 integrates temporally distinct upstream regulatory events and helps program cell fate specification and cell invasion.

  15. Elucidating the fate, transport and processes controlling carbon on the landscape: Biogeochemistry tools for the 21st century

    Science.gov (United States)

    McFarlane, K. J.; Keiluweit, M.; Nico, P. S.; Ognibene, T.; Mayali, X.; Nuccio, E.; Weber, P. K.; Pett-Ridge, J.; Guilderson, T. P.

    2013-12-01

    Globally, more carbon is stored belowground as soil organic matter than in terrestrial vegetation and the atmosphere combined. A critical scientific question is how soils serve as sources and sinks for atmospheric carbon dioxide (CO2) and how these sinks will evolve with expected changes in atmospheric CO2 concentrations, climate, and land-use. Carbon initially enters belowground soil pools as plant detritus, roots, and root exudates. Once in the soil, this organic matter serves as a substrate for decomposer organisms including soil animals, bacteria, and fungi. Most of this carbon is consumed and respired as CO2, but some is converted to microbial biomass and byproducts, which may leave the soil as dissolved organic carbon, be used as a substrate by other microbes, or be stabilized within the soil mineral matrix. Mechanisms that result in the stabilization of soils include: climate stabilization, physical protection within aggregates and organo-mineral complexes, and protection of potential substrates due to physiochemical barriers. These processes, which span broad temporal and spatial scales, are poorly constrained in many dynamic land surface models. At LLNL, we have developed a suite of analytical tools that allow us to follow the movement of carbon at the cell to landscape scale, including: ';Chip-SIP', ';STXM-SIMS', and new sample interfaces for accelerator mass spectrometry (AMS). Experiments, field-based and in vivo, allow us to further the mechanistic understanding of factors that control the fate, transport, and sequestration potential of belowground carbon. The Chip-SIP approach allows us to interrogate which microbial species in a complex community incorporate specific substrates (e.g. cellulose) in order to understand the production of biofuels and better elucidate energy and carbon transfers in wetlands and soils. To disentangle the complex interactions at soil-microbial-film-mineral interfaces with minimal disruption we are using a combination of

  16. 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.

  17. Neurogenin 2 Converts Mesenchymal Stem Cells into a Neural Precursor Fate and Improves Functional Recovery after Experimental Stroke

    Directory of Open Access Journals (Sweden)

    Feng Cheng

    2014-03-01

    Full Text Available Background: Neurogenin2 (Ngn2 is a proneural gene that directs neuronal differentiation of progenitor cells during development. Here, we investigated whether Ngn2 can reprogram MSCs to adopt a neural precursor fate and enhance the therapeutic effects of MSCs after experimental stroke. Methods: In vitro, MSCs were transfected with lenti-GFP or lenti-Ngn2. Following neuronal induction, cells were identified by immunocytochemistry, Western blot and electrophysiological analyses. In a stroke model induced by transient right middle cerebral artery occlusion (MCAO, PBS, GFP-MSCs or Ngn2-MSCs were injected 1 day after MCAO. Behavioral tests, neurological and immunohistochemical assessments were performed. Results: In vitro, Ngn2-MSCs expressed neural stem cells markers (Pax6 and nestin and lost the potential to differentiate into mesodermal cell types. Following neural induction, Ngn2-MSCs expressed higher levels of neuron-specific proteins MAP2, Tuj1 and NeuN, and also expressed voltage-gated Na+ channel, which was absent in GFP-MSCs. In vivo, after transplantation, Ngn2-MSCs significantly reduced apoptotic cells, decreased infarct volume, and increased the expression of VEGF and BDNF. Finally, Ngn2-MSCs treated animals showed the highest functional recovery among the three groups. Conclusions: Ngn2 was sufficient to convert MSCs into a neural precursor fate and transplantation of Ngn2-MSCs was advantageous for the treatment of stroke rats.

  18. 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

  19. The fate of caesium-137 in a soil environment controlled by immobilization on clay minerals

    OpenAIRE

    NAKAO, Atsushi; Funakawa, Shinya; Tsukada, Hirofumi; Kosaki, Takashi

    2012-01-01

    Caesium-137 (137Cs), with its high release rate and long half life, is the most important longterm contributor to environmental contamination of all the radionuclides released by the accident at the Fukushima Dai-ichi nuclear power plant in March 2011. There have been many surveys of the fate of 137Cs in terrestrial environments, especially after the atmospheric nuclear tests of the 1950s and 60s and the Chernobyl accident in 1986. Previous surveys revealed that most of the 137Cs deposited on...

  20. A general model for binary cell fate decision gene circuits with degeneracy: indeterminacy and switch behavior in the absence of cooperativity.

    Directory of Open Access Journals (Sweden)

    Mircea Andrecut

    Full Text Available BACKGROUND: The gene regulatory circuit motif in which two opposing fate-determining transcription factors inhibit each other but activate themselves has been used in mathematical models of binary cell fate decisions in multipotent stem or progenitor cells. This simple circuit can generate multistability and explains the symmetric "poised" precursor state in which both factors are present in the cell at equal amounts as well as the resolution of this indeterminate state as the cell commits to either cell fate characterized by an asymmetric expression pattern of the two factors. This establishes the two alternative stable attractors that represent the two fate options. It has been debated whether cooperativity of molecular interactions is necessary to produce such multistability. PRINCIPAL FINDINGS: Here we take a general modeling approach and argue that this question is not relevant. We show that non-linearity can arise in two distinct models in which no explicit interaction between the two factors is assumed and that distinct chemical reaction kinetic formalisms can lead to the same (generic dynamical system form. Moreover, we describe a novel type of bifurcation that produces a degenerate steady state that can explain the metastable state of indeterminacy prior to cell fate decision-making and is consistent with biological observations. CONCLUSION: The general model presented here thus offers a novel principle for linking regulatory circuits with the state of indeterminacy characteristic of multipotent (stem cells.

  1. A General Model for Binary Cell Fate Decision Gene Circuits with Degeneracy: Indeterminacy and Switch Behavior in the Absence of Cooperativity

    Science.gov (United States)

    Andrecut, Mircea; Halley, Julianne D.; Winkler, David A.; Huang, Sui

    2011-01-01

    Background The gene regulatory circuit motif in which two opposing fate-determining transcription factors inhibit each other but activate themselves has been used in mathematical models of binary cell fate decisions in multipotent stem or progenitor cells. This simple circuit can generate multistability and explains the symmetric “poised” precursor state in which both factors are present in the cell at equal amounts as well as the resolution of this indeterminate state as the cell commits to either cell fate characterized by an asymmetric expression pattern of the two factors. This establishes the two alternative stable attractors that represent the two fate options. It has been debated whether cooperativity of molecular interactions is necessary to produce such multistability. Principal Findings Here we take a general modeling approach and argue that this question is not relevant. We show that non-linearity can arise in two distinct models in which no explicit interaction between the two factors is assumed and that distinct chemical reaction kinetic formalisms can lead to the same (generic) dynamical system form. Moreover, we describe a novel type of bifurcation that produces a degenerate steady state that can explain the metastable state of indeterminacy prior to cell fate decision-making and is consistent with biological observations. Conclusion The general model presented here thus offers a novel principle for linking regulatory circuits with the state of indeterminacy characteristic of multipotent (stem) cells. PMID:21625586

  2. Multiplex Quantitative Histologic Analysis of Human Breast Cancer Cell Signaling and Cell Fate

    Science.gov (United States)

    2010-05-01

    P. Lewis , B. S. Manjunath, and S. K. Fisher, “Automated tool for the detection of cell nuclei in digital microscopic images: Application to retinal...set model and some applications to Mumford -Shah image segmentation,” IEEE Trans. Image Process., vol. 15, no. 5, pp. 1171–1181, May 2006. [37] N. R

  3. 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.

  4. Constraining the Pluripotent Fate of Human Embryonic Stem Cells for Tissue Engineering and Cell Therapy - The Turning Point of Cell-Based Regenerative Medicine.

    Science.gov (United States)

    Parsons, Xuejun H

    2013-10-01

    To date, the lack of a clinically-suitable source of engraftable human stem/progenitor cells with adequate neurogenic potential has been the major setback in developing safe and effective cell-based therapies for regenerating the damaged or lost CNS structure and circuitry in a wide range of neurological disorders. Similarly, the lack of a clinically-suitable human cardiomyocyte source with adequate myocardium regenerative potential has been the major setback in regenerating the damaged human heart. Given the limited capacity of the CNS and heart for self-repair, there is a large unmet healthcare need to develop stem cell therapies to provide optimal regeneration and reconstruction treatment options to restore normal tissues and function. Derivation of human embryonic stem cells (hESCs) provides a powerful in vitro model system to investigate molecular controls in human embryogenesis as well as an unlimited source to generate the diversity of human somatic cell types for regenerative medicine. However, realizing the developmental and therapeutic potential of hESC derivatives has been hindered by the inefficiency and instability of generating clinically-relevant functional cells from pluripotent cells through conventional uncontrollable and incomplete multi-lineage differentiation. Recent advances and breakthroughs in hESC research have overcome some major obstacles in bringing hESC therapy derivatives towards clinical applications, including establishing defined culture systems for de novo derivation and maintenance of clinical-grade pluripotent hESCs and lineage-specific differentiation of pluripotent hESCs by small molecule induction. Retinoic acid was identified as sufficient to induce the specification of neuroectoderm direct from the pluripotent state of hESCs and trigger a cascade of neuronal lineage-specific progression to human neuronal progenitors and neurons of the developing CNS in high efficiency, purity, and neuronal lineage specificity by promoting

  5. Critical zone properties control the fate of nitrogen during experimental rainfall in montane forests of the Colorado Front Range

    Science.gov (United States)

    Hinckley, Eve-Lyn S.; Ebel, Brian A.; Barnes, Rebecca T.; Murphy, Sheila F.; Anderson, Suzanne P.

    2017-01-01

    Several decades of research in alpine ecosystems have demonstrated links among the critical zone, hydrologic response, and the fate of elevated atmospheric nitrogen (N) deposition. Less research has occurred in mid-elevation forests, which may be important for retaining atmospheric N deposition. To explore the fate of N in the montane zone, we conducted plot-scale experimental rainfall events across a north–south transect within a catchment of the Boulder Creek Critical Zone Observatory. Rainfall events mimicked relatively common storms (20–50% annual exceedance probability) and were labeled with 15N-nitrate (NO3−">NO−3NO3−) and lithium bromide tracers. For 4 weeks, we measured soil–water and leachate concentrations of Br−, 15NO3−,">15NO−3,15NO3−, and NO3−">NO−3NO3− daily, followed by recoveries of 15N species in bulk soils and microbial biomass. Tracers moved immediately into the subsurface of north-facing slope plots, exhibiting breakthrough at 10 and 30 cm over 22 days. Conversely, little transport of Br− or 15NO3−">15NO−315NO3− occurred in south-facing slope plots; tracers remained in soil or were lost via pathways not measured. Hillslope position was a significant determinant of soil 15N-NO3−">NO−3NO3− recoveries, while soil depth and time were significant determinants of 15N recovery in microbial biomass. Overall, 15N recovery in microbial biomass and leachate was greater in upper north-facing slope plots than lower north-facing (toeslope) and both south-facing slope plots in August; by October, 15N recovery in microbial N biomass within south-facing slope plots had increased substantially. Our results point to the importance of soil properties in controlling the fate of N in mid-elevation forests during the summer season.

  6. Detection of a novel population of fetal thymocytes characterized by preferential emigration and a TCRgammadelta+ T cell fate after dioxin exposure.

    Science.gov (United States)

    Majora, Marc; Frericks, Markus; Temchura, Vladimir; Reichmann, Gaby; Esser, Charlotte

    2005-11-01

    T cell maturation into TCRalphabeta(+) or TCRgammadelta(+) cells from common immature CD4(-)CD8(-)(DN) precursors occurs in the thymus, and is controlled through ordered regulation of genes. The aryl hydrocarbon receptor (AHR), a latent cytoplasmic transcription factor, affects thymocyte maturation and differentiation at several stages, also including DN cells. We analyzed in murine fetal thymus organ cultures (FTOC) the outcome of AHR-signaling and found a higher frequency of DN TCRgammadelta(+) cells in the presence of the AHR-activating ligand TCDD. We detected a novel population of CD25(int/lo)CD44(hi) cells associated with preferential emigration and a TCRgammadelta(+) T cell fate of thymocytes. Sorted DN TCRgammadelta(+) emigrants could proliferate if IL-2 was available. Moreover, they suppressed the proliferation of co-cultivated, activated CD4(+) T cells. Gene expression profiles of purified DN emigrants from TCDD*FTOC revealed 295 modulated genes, 10% of which are genes of the immune system. For instance, RAG-1, TdT, and Gfi-1 were downregulated, yet genes indicative of mature thymocytes were upregulated. In conclusion, we have detected changes in the differentiation programme of fetal DN thymocytes after ligand-activation of the AHR. In particular, we observed a higher frequency of DN TCRgammadelta(+) cells with high emigration potential, and possible regulatory functions.

  7. The Wnt5a/Ror2 pathway is associated with determination of the differentiation fate of bone marrow mesenchymal stem cells in vascular calcification.

    Science.gov (United States)

    Xin, Huaping; Xin, Fang; Zhou, Shaoqiong; Guan, Siming

    2013-03-01

    Accumulating evidence have demonstrated that mesenchymal stem cells (MSCs) are involved in the initiation and progression of various vascular diseases. Canonical Wnt signaling controls the fate of MSCs, and plays an important role in vascular calcification. However, vascular calcification can be inhibited by the non-canonical Wnt signaling pathway Wnt5a/Ror2. This study aimed to investigate whether the Wnt5a/Ror2 pathway is associated with determination of the differentiation fate of MSCs in vascular calcification. Direct co-cultures were established by seeding smooth muscle cells (SMCs) or calcified SMCs and MSCs together at ratios of SMCs or calcified SMCs 15x104; SMCs or calcified SMCs 5x104: MSCs 10x104, SMCs or calcified SMCs 10x104: MSCs 5x104. Osteosynthesis-inducing medium (OS) was added to the culture medium in the groups of MSCs with non-calcified SMCs. Cells were cultured for nine days. Osteoblastic differentiation was evaluated by cell morphology and the activity of alkaline phosphatase (ALP) in cell lysates and ALP staining. Furthermore, we investigated the inhibition of Wnt signaling, and observed that the members of the non-canonical signaling pathway Wnt5a/Ror2 were expressed in each group. Additionally, MSCs cultured in culture media with OS did not differentiate into an osteoblast phenotype when in direct contact with non-calcified SMCs, irrespective of the number of MSCs. However, an osteoblast phenotype was observed when MSCs were cultured in media without OS differentiation towards direct contact with calcified SMCs, and the levels of osteoblastic markers had a direct correlation with the number of MSCs. Of note, the Wnt5a protein was associated with the levels of calcification, thus, although rarely detected in non-calcification, Ror2 mRNA in the non-calcified groups was significantly higher compared to that in the calcified groups. Therefore, the Wnt5a/Ror2 pathway is associated with determination of the differentiation fate of bone marrow

  8. Perivascular instruction of cell genesis and fate in the adult brain.

    Science.gov (United States)

    Goldman, Steven A; Chen, Zhuoxun

    2011-10-26

    The perivascular niche for neurogenesis was first reported as the co-association of newly generated neurons and their progenitors with both dividing and mitotically quiescent endothelial cells in restricted regions of the brain in adult birds and mammals alike. This review attempts to summarize our present understanding of the interaction of blood vessels with neural stem and progenitor cells, addressing both glial and neuronal progenitor cell interactions in the perivascular niche. We review the molecular interactions that are most critical to the endothelial control of stem and progenitor cell mobilization and differentiation. The focus throughout will be on defining those perivascular ligand-receptor interactions shared among these systems, as well as those that clearly differ as a function of cell type and setting, by which specificity may be achieved in the development of targeted therapeutics.

  9. Fate of D3 mouse embryonic stem cells exposed to X-rays or carbon ions.

    Science.gov (United States)

    Luft, S; Pignalosa, D; Nasonova, E; Arrizabalaga, O; Helm, A; Durante, M; Ritter, S

    2014-01-15

    The risk of radiation exposure during embryonic development is still a major problem in radiotoxicology. In this study we investigated the response of the murine embryonic stem cell (mESC) line D3 to two radiation qualities: sparsely ionizing X-rays and densely ionizing carbon ions. We analyzed clonogenic cell survival, proliferation, induction of chromosome aberrations as well as the capability of cells to differentiate to beating cardiomyocytes up to 3 days after exposure. Our results show that, for all endpoints investigated, carbon ions are more effective than X-rays at the same radiation dose. Additionally, in long term studies (≥8 days post-irradiation) chromosomal damage and the pluripotency state were investigated. These studies reveal that pluripotency markers are present in the progeny of cells surviving the exposure to both radiation types. However, only in the progeny of X-ray exposed cells the aberration frequency was comparable to that of the control population, while the progeny of carbon ion irradiated cells harbored significantly more aberrations than the control, generally translocations. We conclude that cells surviving the radiation exposure maintain pluripotency but may carry stable chromosomal rearrangements after densely ionizing radiation.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Luo, Qingyin; Beaver, Jill M; Liu, Yuan; Zhang, Zunzhen

    2017-02-09

    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.

  12. 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

    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...... 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...

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Control of apoptosis by asymmetric cell division.

    Directory of Open Access Journals (Sweden)

    Julia Hatzold

    2008-04-01

    Full Text Available Asymmetric cell division and apoptosis (programmed cell death are two fundamental processes that are important for the development and function of multicellular organisms. We have found that the processes of asymmetric cell division and apoptosis can be functionally linked. Specifically, we show that asymmetric cell division in the nematode Caenorhabditis elegans is mediated by a pathway involving three genes, dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail, that directly control the enzymatic machinery responsible for apoptosis. Interestingly, the MIDA1-like protein GlsA of the alga Volvox carteri, as well as the Snail-related proteins Snail, Escargot, and Worniu of Drosophila melanogaster, have previously been implicated in asymmetric cell division. Therefore, C. elegans dnj-11 MIDA1, ces-2 HLF, and ces-1 Snail may be components of a pathway involved in asymmetric cell division that is conserved throughout the plant and animal kingdoms. Furthermore, based on our results, we propose that this pathway directly controls the apoptotic fate in C. elegans, and possibly other animals as well.

  15. Evaluation and characterization of mechanisms controlling fate and effects of Army smokes

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, D.A.; Ligotke, M.W.; Bolton, H. Jr.; Fellows, R.J.; Van Voris, P.; McKinley, J.P.; Mi, Shu-mei W.; McFadden, K.M.

    1990-08-01

    The primary objective of this study was to characterize the fate and response of soil and biotic components of the terrestrial environment to aerosols, deposited brass, and brass in combination with fog oil. Important physical, chemical, and biotic aspects were investigated using an environmental wind tunnel. Air/surface deposition rates were determined for foliar and soil surfaces, both in the absence and presence of fog oil. Deposition velocities for foliage ranged from 0.1 to 1.0 cm/s at wind speeds of 2 to 10 mph, respectively. Foliar contact toxicity was assessed using five different types of terrestrial vegetation representative of Army training sites and surrounding environments. No significant foliar contact toxicity was observed for brass. The weathering and chemistry of brass aerosols deposited and amended to soils was assessed, along with the impacts of acid precipitation and moisture regimes on weathering rates. Rates of brass weathering and the fate of solubilized Cu and Zn are discussed. The influence of soil weathering processes and brass solubilization on seed germination indicated no detectable effects of brass. However, moderate toxicity effects were noted after seed germination indicated no detectable effects of brass. However, moderate toxicity effects were noted after 160 days of soil incubation. The effects were proportional to soil-loading levels. Influence of soil weathering processes and contaminant solubilization on soil microbiological activities indicated that soil dehydrogenase activity was more susceptible to impacts than was phosphatase activity or microbial biomass. Nitrifying bacteria and heterotrophic bacteria were not significantly affected by brass. Invertebrates (earthworms) associated with soil contaminated with brass were only slightly impacted, and only at loading rates >445 {mu}g/cm{sup 2}.

  16. Recent advances in interactions of designed nanoparticles and cells with respect to cellular uptake, intracellular fate, degradation and cytotoxicity

    Science.gov (United States)

    Deng, Jun; Gao, Changyou

    2016-10-01

    The unique features of nanomaterials have led to their rapid development in the biomedical field. In particular, functionalized nanoparticles (NPs) are extensively used in the delivery of drugs and genes, bio-imaging and diagnosis. Hence, the interaction between NPs and cells is one of the most important issues towards understanding the true nature of the NP-mediated biological effects. Moreover, the intracellular safety concern of the NPs as a result of intracellular NP degradation remains to be clarified in detail. This review presents recent advances in the interactions of designed NPs and cells. The focus includes the governing factors on cellular uptake and the intracellular fate of NPs, and the degradation of NPs and its influence on nanotoxicity. Some basic consideration is proposed for optimizing the NP-cell interaction and designing NPs of better biocompatiblity for biomedical application.

  17. Early postnatal respiratory viral infection alters hippocampal neurogenesis, cell fate, and neuron morphology in the neonatal piglet.

    Science.gov (United States)

    Conrad, Matthew S; Harasim, Samantha; Rhodes, Justin S; Van Alstine, William G; Johnson, Rodney W

    2015-02-01

    Respiratory viral infections are common during the neonatal period in humans, but little is known about how early-life infection impacts brain development. The current study used a neonatal piglet model as piglets have a gyrencephalic brain with growth and development similar to human infants. Piglets were inoculated with porcine reproductive and respiratory syndrome virus (PRRSV) to evaluate how chronic neuroinflammation affects hippocampal neurogenesis and neuron morphology. Piglets in the neurogenesis study received one bromodeoxyuridine injection on postnatal day (PD) 7 and then were inoculated with PRRSV. Piglets were sacrificed at PD 28 and the number of BrdU+ cells and cell fate were quantified in the dentate gyrus. PRRSV piglets showed a 24% reduction in the number of newly divided cells forming neurons. Approximately 15% of newly divided cells formed microglia, but this was not affected by sex or PRRSV. Additionally, there was a sexual dimorphism of new cell survival in the dentate gyrus where males had more cells than females, and PRRSV infection caused a decreased survival in males only. Golgi impregnation was used to characterize dentate granule cell morphology. Sholl analysis revealed that PRRSV caused a change in inner granule cell morphology where the first branch point was extended further from the cell body. Males had more complex dendritic arbors than females in the outer granule cell layer, but this was not affected by PRRSV. There were no changes to dendritic spine density or morphology distribution. These findings suggest that early-life viral infection can impact brain development.

  18. 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.

  19. Cell-to-cell signaling influences the fate of prostate cancer stem cells and their potential to generate more aggressive tumors.

    Directory of Open Access Journals (Sweden)

    Luisa Salvatori

    Full Text Available An increasing number of malignancies has been shown to be initiated and propelled by small subpopulations of cancer stem cells (CSC. However, whether tumor aggressiveness is driven by CSC and by what extent this property may be relevant within the tumor mass is still unsettled. To address this issue, we isolated a rare tumor cell population on the basis of its CD44(+CD24(- phenotype from the human androgen-independent prostate carcinoma cell line DU145 and established its CSC properties. The behavior of selected CSC was investigated with respect to the bulk DU145 cells. The injection of CSC in nude mice generated highly vascularized tumors infiltrating the adjacent tissues, showing high density of neuroendocrine cells and expressing low levels of E-cadherin and β-catenin as well as high levels of vimentin. On the contrary, when a comparable number of unsorted DU145 cells were injected the resulting tumors were less aggressive. To investigate the different features of tumors in vivo, the influence of differentiated tumor cells on CSC was examined in vitro by growing CSC in the absence or presence of conditioned medium from DU145 cells. CSC grown in permissive conditions differentiated into cell populations with features similar to those of cells held in aggressive tumors generated from CSC injection. Differently, conditioned medium induced CSC to differentiate into a cell phenotype comparable to cells of scarcely aggressive tumors originated from bulk DU145 cell injection. These findings show for the first time that CSC are able to generate differentiated cells expressing either highly or scarcely aggressive phenotype, thus influencing prostate cancer progression. The fate of CSC was determined by signals released from tumor environment. Moreover, using microarray analysis we selected some molecules which could be involved in this cell-to-cell signaling, hypothesizing their potential value for prognostic or therapeutic applications.

  20. BLADE-ON-PETIOLE1 and 2 Control Arabidopsis Lateral Organ Fate through Regulation of LOB-Domain and Adaxial-Abaxial Polarity Genes

    Science.gov (United States)

    Continuous lateral organ formation is critical for higher plants to produce their characteristic architectures, but the regulatory pathways that specify organ cell fate are still poorly understood. Here, we report a novel function for BLADE-ON-PETIOLE1 (BOP1) and BOP2 in regulating Arabidopsis later...

  1. 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.

  2. 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.

  3. Restoration of p53 Expression in Human Cancer Cell Lines Upregulates the Expression of Notch1: Implications for Cancer Cell Fate Determination after Genotoxic Stress1

    Science.gov (United States)

    Alimirah, Fatouma; Panchanathan, Ravichandran; Davis, Francesca J; Chen, Jianming; Choubey, Divaker

    2007-01-01

    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, p53-mediated 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 p53-mediated upregulation of Notch1 expression in human cancer cell lines contributes to cell fate determination after genotoxic stress. PMID:17534448

  4. Immune outcomes in the liver: Is CD8 T cell fate determined by the environment?

    Science.gov (United States)

    Wong, Yik Chun; Tay, Szun Szun; McCaughan, Geoffrey W; Bowen, David G; Bertolino, Patrick

    2015-10-01

    The liver is known for its tolerogenic properties. This unique characteristic is associated with persistent infection of the liver by the hepatitis B and C viruses. Improper activation of cellular adaptive immune responses within the liver and immune exhaustion over time both contribute to ineffective cytotoxic T cell responses to liver-expressed antigens in animal models, and likely play a role in incomplete clearance of chronic hepatitis virus infections in humans. However, under some conditions, functional immune responses can be elicited against hepatic antigens, resulting in control of hepatotropic infections. In order to develop improved therapeutics in immune-mediated chronic liver diseases, including viral hepatitis, it is essential to understand how intrahepatic immunity is regulated. This review focuses on CD8 T cell immunity directed towards foreign antigens expressed in the liver, and explores how the liver environment dictates the outcome of intrahepatic CD8 T cell responses. Potential strategies to rescue unresponsive CD8 T cells in the liver are also discussed.

  5. GSK3 as a sensor determining cell fate in the brain

    Directory of Open Access Journals (Sweden)

    Adam R Cole

    2012-02-01

    Full Text Available Glycogen synthase kinase 3 (GSK3 is an unusual serine/threonine kinase that controls many neuronal functions, including neurite outgrowth, synapse formation, neurotransmission and neurogenesis. It mediates these functions by phosphorylating a wide range of substrates involved in gene transcription, metabolism, apoptosis, cytoskeletal dynamics, signal transduction, lipid membrane dynamics and trafficking, amongst others. This complicated list of diverse substrates generally follow a more simple pattern: substrates negatively regulated by GSK3-mediated phosphorylation favour a proliferative/survival state, while substrates positively regulated by GSK3 favour a more differentiated/functional state. Accordingly, GSK3 activity is higher in differentiated cells than undifferentiated cells and physiological (Wnt, growth factors and pharmacological inhibitors of GSK3 promote the proliferative capacity of embryonic stem cells. In the brain, the level of GSK3 activity influences neural progenitor cell proliferation/differentiation in neuroplasticity and repair, as well as efficient neurotransmission in differentiated adult neurons. While defects in GSK3 activity are unlikely to be the primary cause of neurodegenerative diseases, therapeutic regulation of its activity to promote a proliferative/survival versus differentiated/mature functional environment in the brain could be a powerful strategy for treatment of neurodegenerative and other mental disorders.

  6. An essential role for RAX homeoprotein and NOTCH-HES signaling in Otx2 expression in embryonic retinal photoreceptor cell fate determination.

    Science.gov (United States)

    Muranishi, Yuki; Terada, Koji; Inoue, Tatsuya; Katoh, Kimiko; Tsujii, Toshinori; Sanuki, Rikako; Kurokawa, Daisuke; Aizawa, Shinichi; Tamaki, Yasuhiro; Furukawa, Takahisa

    2011-11-16

    The molecular mechanisms underlying cell fate determination from common progenitors in the vertebrate CNS remain elusive. We previously reported that the OTX2 homeoprotein regulates retinal photoreceptor cell fate determination. While Otx2 transactivation is a pivotal process for photoreceptor cell fate determination, its transactivation mechanism in the retina is unknown. Here, we identified an evolutionarily conserved Otx2 enhancer of ∼500 bp, named embryonic enhancer locus for photoreceptor Otx2 transcription (EELPOT), which can recapitulate initial Otx2 expression in the embryonic mouse retina. We found that the RAX homeoprotein interacts with EELPOT to transactivate Otx2, mainly in the final cell cycle of retinal progenitors. Conditional inactivation of Rax results in downregulation of Otx2 expression in vivo. We also showed that NOTCH-HES signaling negatively regulates EELPOT to suppress Otx2 expression. These results suggest that the integrated activity of cell-intrinsic and -extrinsic factors on EELPOT underlies the molecular basis of photoreceptor cell fate determination in the embryonic retina.

  7. TNF receptor signaling inhibits cardiomyogenic differentiation of cardiac stem cells and promotes a neuroadrenergic-like fate.

    Science.gov (United States)

    Hamid, Tariq; Xu, Yuanyuan; Ismahil, Mohamed Ameen; Li, Qianhong; Jones, Steven P; Bhatnagar, Aruni; Bolli, Roberto; Prabhu, Sumanth D

    2016-11-01

    Despite expansion of resident cardiac stem cells (CSCs; c-kit(+)Lin(-)) after myocardial infarction, endogenous repair processes are insufficient to prevent adverse cardiac remodeling and heart failure (HF). This suggests that the microenvironment in post-ischemic and failing hearts compromises CSC regenerative potential. Inflammatory cytokines, such as tumor necrosis factor-α (TNF), are increased after infarction and in HF; whether they modulate CSC function is unknown. As the effects of TNF are specific to its two receptors (TNFRs), we tested the hypothesis that TNF differentially modulates CSC function in a TNFR-specific manner. CSCs were isolated from wild-type (WT), TNFR1-/-, and TNFR2-/- adult mouse hearts, expanded and evaluated for cell competence and differentiation in vitro in the absence and presence of TNF. Our results indicate that TNF signaling in murine CSCs is constitutively related primarily to TNFR1, with TNFR2 inducible after stress. TNFR1 signaling modestly diminished CSC proliferation, but, along with TNFR2, augmented CSC resistance to oxidant stress. Deficiency of either TNFR1 or TNFR2 did not impact CSC telomerase activity. Importantly, TNF, primarily via TNFR1, inhibited cardiomyogenic commitment during CSC differentiation, and instead promoted smooth muscle and endothelial fates. Moreover, TNF, via both TNFR1 and TNFR2, channeled an alternate CSC neuroadrenergic-like fate (capable of catecholamine synthesis) during differentiation. Our results suggest that elevated TNF in the heart restrains cardiomyocyte differentiation of resident CSCs and may enhance adrenergic activation, both effects that would reduce the effectiveness of endogenous cardiac repair and the response to exogenous stem cell therapy, while promoting adverse cardiac remodeling.

  8. Four and a Half LIM Domains 1b (Fhl1b Is Essential for Regulating the Liver versus Pancreas Fate Decision and for β-Cell Regeneration.

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    Jin Xu

    2016-02-01

    Full Text Available The liver and pancreas originate from overlapping embryonic regions, and single-cell lineage tracing in zebrafish has shown that Bone morphogenetic protein 2b (Bmp2b signaling is essential for determining the fate of bipotential hepatopancreatic progenitors towards the liver or pancreas. Despite its pivotal role, the gene regulatory networks functioning downstream of Bmp2b signaling in this process are poorly understood. We have identified four and a half LIM domains 1b (fhl1b, which is primarily expressed in the prospective liver anlage, as a novel target of Bmp2b signaling. fhl1b depletion compromised liver specification and enhanced induction of pancreatic cells from endodermal progenitors. Conversely, overexpression of fhl1b favored liver specification and inhibited induction of pancreatic cells. By single-cell lineage tracing, we showed that fhl1b depletion led lateral endodermal cells, destined to become liver cells, to become pancreatic cells. Reversely, when fhl1b was overexpressed, medially located endodermal cells, fated to differentiate into pancreatic and intestinal cells, contributed to the liver by directly or indirectly modulating the discrete levels of pdx1 expression in endodermal progenitors. Moreover, loss of fhl1b increased the regenerative capacity of β-cells by increasing pdx1 and neurod expression in the hepatopancreatic ductal system. Altogether, these data reveal novel and critical functions of Fhl1b in the hepatic versus pancreatic fate decision and in β-cell regeneration.

  9. F-actin cytoskeleton and the fate of organelles in chromaffin cells.

    Science.gov (United States)

    Villanueva, José; Gimenez-Molina, Yolanda; Viniegra, Salvador; Gutiérrez, Luis M

    2016-06-01

    In addition to playing a fundamental structural role, the F-actin cytoskeleton in neuroendocrine chromaffin cells has a prominent influence on governing the molecular mechanism and regulating the secretory process. Performing such roles, the F-actin network might be essential to first transport, and later locate the cellular organelles participating in the secretory cycle. Chromaffin granules are transported from the internal cytosolic regions to the cell periphery along microtubular and F-actin structures. Once in the cortical region, they are embedded in the F-actin network where these vesicles experience restrictions in motility. Similarly, mitochondria transport is affected by both microtubule and F-actin inhibitors and suffers increasing motion restrictions when they are located in the cortical region. Therefore, the F-actin cortex is a key factor in defining the existence of two populations of cortical and perinuclear granules and mitochondria which could be distinguished by their different location and mobility. Interestingly, other important organelles for controlling intracellular calcium levels, such as the endoplasmic reticulum network, present clear differences in distribution and much lower mobility than chromaffin vesicles and mitochondria. Nevertheless, both mitochondria and the endoplasmic reticulum appear to distribute in the proximity of secretory sites to fulfill a pivotal role, forming triads with calcium channels ensuring the fine tuning of the secretory response. This review presents the contributions that provide the basis for our current view regarding the influence that F-actin has on the distribution of organelles participating in the release of catecholamines in chromaffin cells, and summarizes this knowledge in simple models. In chromaffin cells, organelles such as granules and mitochondria distribute forming cortical and perinuclear populations whereas others like the ER present homogenous distributions. In the present review we discuss

  10. Subcellular localization and functional domain studies of DEFECTIVE KERNEL1 in maize and Arabidopsis suggest a model for aleurone cell fate specification involving CRINKLY4 and SUPERNUMERARY ALEURONE LAYER1.

    Science.gov (United States)

    Tian, Qing; Olsen, Lene; Sun, Beimeng; Lid, Stein Erik; Brown, Roy C; Lemmon, Betty E; Fosnes, Kjetil; Gruis, Darren Fred; Opsahl-Sorteberg, Hilde-Gunn; Otegui, Marisa S; Olsen, Odd-Arne

    2007-10-01

    DEFECTIVE KERNEL1 (DEK1), which consists of a membrane-spanning region (DEK1-MEM) and a calpain-like Cys proteinase region (DEK1-CALP), is essential for aleurone cell formation at the surface of maize (Zea mays) endosperm. Immunolocalization and FM4-64 dye incubation experiments showed that DEK1 and CRINKLY4 (CR4), a receptor kinase implicated in aleurone cell fate specification, colocalized to plasma membrane and endosomes. SUPERNUMERARY ALEURONE LAYER1 (SAL1), a negative regulator of aleurone cell fate encoding a class E vacuolar sorting protein, colocalized with DEK1 and CR4 in endosomes. Immunogold localization, dual-axis electron tomography, and diffusion of fluorescent dye tracers showed that young aleurone cells established symplastic subdomains through plasmodesmata of larger dimensions than those connecting starchy endosperm cells and that CR4 preferentially associated with plasmodesmata between aleurone cells. Genetic complementation experiments showed that DEK1-CALP failed to restore wild-type phenotypes in maize and Arabidopsis thaliana dek1 mutants, and DEK1-MEM also failed to restore wild-type phenotypes in Arabidopsis dek1-1 mutants. Instead, ectopic expression of DEK1-MEM under the control of the cauliflower mosaic virus 35S promoter gave a dominant negative phenotype. These data suggest a model for aleurone cell fate specification in which DEK1 perceives and/or transmits a positional signal, CR4 promotes the lateral movement of aleurone signaling molecules between aleurone cells, and SAL1 maintains the proper plasma membrane concentration of DEK1 and CR4 proteins via endosome-mediated recycling/degradation.

  11. Machine learning classification of cell-specific cardiac enhancers uncovers developmental subnetworks regulating progenitor cell division and cell fate specification

    OpenAIRE

    Ahmad, Shaad M.; Busser, Brian W; Huang, Di; Cozart, Elizabeth J.; Michaud, Sébastien; Zhu, Xianmin; Jeffries, Neal; Aboukhalil, Anton; Bulyk, Martha L.; Ovcharenko, Ivan; Michelson, Alan M.

    2014-01-01

    The Drosophila heart is composed of two distinct cell types, the contractile cardial cells (CCs) and the surrounding non-muscle pericardial cells (PCs), development of which is regulated by a network of conserved signaling molecules and transcription factors (TFs). Here, we used machine learning with array-based chromatin immunoprecipitation (ChIP) data and TF sequence motifs to computationally classify cell type-specific cardiac enhancers. Extensive testing of predicted enhancers at single-c...

  12. Cell fate decisions in malignant hematopoiesis: leukemia phenotype is determined by distinct functional domains of the MN1 oncogene.

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    Courteney K Lai

    Full Text Available Extensive molecular profiling of leukemias and preleukemic diseases has revealed that distinct clinical entities, like acute myeloid (AML and T-lymphoblastic leukemia (T-ALL, share similar pathogenetic mutations. It is not well understood how the cell of origin, accompanying mutations, extracellular signals or structural differences in a mutated gene determine the phenotypic identity of leukemias. We dissected the functional aspects of different protein regions of the MN1 oncogene and their effect on the leukemic phenotype, building on the ability of MN1 to induce leukemia without accompanying mutations. We found that the most C-terminal region of MN1 was required to block myeloid differentiation at an early stage, and deletion of an extended C-terminal region resulted in loss of myeloid identity and cell differentiation along the T-cell lineage in vivo. Megakaryocytic/erythroid lineage differentiation was blocked by the N-terminal region. In addition, the N-terminus was required for proliferation and leukemogenesis in vitro and in vivo through upregulation of HoxA9, HoxA10 and Meis2. Our results provide evidence that a single oncogene can modulate cellular identity of leukemic cells based on its active gene regions. It is therefore likely that different mutations in the same oncogene may impact cell fate decisions and phenotypic appearance of malignant diseases.

  13. IFPA Trophoblast Research Award Lecture: the dynamic role of Bcl-2 family members in trophoblast cell fate.

    Science.gov (United States)

    Ray, J; Jurisicova, A; Caniggia, I

    2009-03-01

    Bcl-2 family members are important regulators of cell fate in normal organ development and in disease status. Pro- and anti-apoptotic members of this family function through a complex network of homo- and hetero-dimers to determine whether a cell lives or dies. Members of the Bcl-2 family are classically recognized for their role in apoptosis, yet emerging evidence has highlighted their importance in the regulation of cell cycle. Cellular proliferation, differentiation and death accompany early placental development of the trophoblast lineage. We have recently reported on the expression and function of two Bcl-2 family members in normal placental development, namely the pro-apoptotic Mtd/Bok, and its anti-apoptotic partner Mcl-1 and have found that their expression is upregulated by low oxygen, a key mediator of trophoblast cell proliferation in early placentation. Interestingly, we have also reported that the expression of the Mtd/Mcl-1 system is altered in preeclampsia, a placental pathology associated with a status of oxidative stress and typically characterized by an immature proliferative trophoblast phenotype and excessive trophoblast cell death. In this pathology levels of pro-apototic Mtd-L and Mtd-P are increased and anti-apoptotic Mcl-1 is cleaved in to a pro-apoptotic isoform. Disruption in Mtd/Mcl-1 expression seen in preeclampsia may contribute to both the increased apoptosis and hyperproliferative nature of this disorder.

  14. Activation of non-canonical Wnt/JNK pathway by Wnt3a is associated with differentiation fate determination of human bone marrow stromal (mesenchymal) stem cells

    DEFF Research Database (Denmark)

    Qiu, Weimin; Chen, Li; Kassem, Moustapha

    2011-01-01

    The canonical Wnt signaling pathway can determine human bone marrow stromal (mesenchymal) stem cell (hMSC) differentiation fate into osteoblast or adipocyte lineages. However, its downstream targets in MSC are not well characterized. Thus, using DNA microarrays, we compared global gene expression...

  15. β-catenin/Wnt signaling controls progenitor fate in the developing and regenerating zebrafish retina

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    Meyers Jason R

    2012-08-01

    Full Text Available Abstract Background The zebrafish retina maintains two populations of stem cells: first, the germinal zone or ciliary marginal zone (CMZ contains multipotent retinal progenitors that add cells to the retinal periphery as the fish continue to grow; second, radial glia (Müller cells occasionally divide asymmetrically to generate committed progenitors that differentiate into rod photoreceptors, which are added interstitially throughout the retina with growth. Retinal injury stimulates Müller glia to dedifferentiate, re-enter the cell cycle, and generate multipotent retinal progenitors similar to those in the CMZ to replace missing neurons. The specific signals that maintain these two distinct populations of endogenous retinal stem cells are not understood. Results We used genetic and pharmacological manipulation of the β-catenin/Wnt signaling pathway to show that it is required to maintain proliferation in the CMZ and that hyperstimulation of β-catenin/Wnt signaling inhibits normal retinal differentiation and expands the population of proliferative retinal progenitors. To test whether similar effects occur during regeneration, we developed a method for making rapid, selective photoreceptor ablations in larval zebrafish with intense light. We found that dephosphorylated β-catenin accumulates in Müller glia as they re-enter the cell cycle following injury, but not in Müller glia that remain quiescent. Activation of Wnt signaling is required for regenerative proliferation, and hyperstimulation results in loss of Müller glia from the INL as all proliferative cells move into the ONL. Conclusions β-catenin/Wnt signaling is thus required for the maintenance of retinal progenitors during both initial development and lesion-induced regeneration, and is sufficient to prevent differentiation of those progenitors and maintain them in a proliferative state. This suggests that the β-catenin/Wnt cascade is part of the shared molecular circuitry that

  16. Cell differentiation versus cell death: extracellular glucose is a key determinant of cell fate following oxidative stress exposure

    OpenAIRE

    Poulsen, R C; Knowles, H.J.; Carr, A. J.; HULLEY, P. A.

    2014-01-01

    Cells, particularly mechano-sensitive musculoskeletal cells such as tenocytes, routinely encounter oxidative stress. Oxidative stress can not only stimulate tissue repair, but also cause damage leading to tissue degeneration. As diabetes is associated with increased oxidative damage as well as increased risk of tendon degeneration, the aim of this study was to determine if extracellular glucose levels alter the response of tendon cells to oxidative stress. Primary human tenocytes were culture...

  17. 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.

  18. Nanotopographical Control of Stem Cell Differentiation

    Directory of Open Access Journals (Sweden)

    Laura E. McNamara

    2010-01-01

    Full Text Available Stem cells have the capacity to differentiate into various lineages, and the ability to reliably direct stem cell fate determination would have tremendous potential for basic research and clinical therapy. Nanotopography provides a useful tool for guiding differentiation, as the features are more durable than surface chemistry and can be modified in size and shape to suit the desired application. In this paper, nanotopography is examined as a means to guide differentiation, and its application is described in the context of different subsets of stem cells, with a particular focus on skeletal (mesenchymal stem cells. To address the mechanistic basis underlying the topographical effects on stem cells, the likely contributions of indirect (biochemical signal-mediated and direct (force-mediated mechanotransduction are discussed. Data from proteomic research is also outlined in relation to topography-mediated fate determination, as this approach provides insight into the global molecular changes at the level of the functional effectors.

  19. Intraclonal competition limits the fate determination of regulatory T cells 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

    2009-06-01

    Because the deletion of self-reactive T cells is incomplete, thymic development of natural Foxp3+CD4+ regulatory T cells (Treg cells) is required for preventing autoimmunity. However, the function of T cell antigen 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. Unexpectedly, we found that efficient thymic Treg cell development occurred only when the antigen-specific Treg cell precursors were present at low clonal frequency (o1%) in a normal thymus. Using retroviral vectors and bone marrow chimeras, we observed similar activity with two other Treg cell-derived TCRs. Our data demonstrate that thymic Treg cell development is a 'TCR-instructive' process involving a niche that can be saturable at much lower clonal frequencies than is the niche for positive selection.

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

    Directory of Open Access Journals (Sweden)

    Ueno Kazuko

    2009-04-01

    Full Text Available Abstract Background 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. Results 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

  1. MicroRNA-125b/Lin28 pathway contributes to the mesendodermal fate decision of embryonic stem cells.

    Science.gov (United States)

    Wang, Jia; Cao, Nan; Yuan, Min; Cui, Huijuan; Tang, Yuanjia; Qin, Lianju; Huang, Xinfang; Shen, Nan; Yang, Huang-Tian

    2012-06-10

    MicroRNAs (miRNAs) are important regulators of cell fate decisions, while the miRNAs and their targets in the regulation of stem cell differentiation are largely unidentified. Here we report novel functions of miR-125b/Lin28 axis in the regulation of mouse embryonic stem cell (mESC) lineage specification and cardiomyocyte differentiation. With a MicroRNA Array screen, we identified a number of miRNAs significantly changed during ESC differentiation, among which miR-125b showed a marked reduction during early differentiation. The abundantly expressed miR-125b in undifferentiated mESCs was dramatically downregulated to a level hardly detected during differentiation day 3 to 5, with a concomitant upregulation of Lin28. Ectopically expressing miR-125b did not alter characteristics of undifferentiated mESCs, whereas it impaired the endoderm and mesoderm development, but not the ectoderm, and inhibited cardiomyocyte formation. We further demonstrate that miR-125b targeted the 3'-untranslated region of Lin28 and reduced the abundance of Lin28 at both mRNA and protein levels. Moreover, phenotypes of miR-125b overexpressing cells were mimicked by downregulation of Lin28 and rescued by reintroduction of Lin28. In addition, the impaired cardiogenesis in miR-125b-introduced cells was greatly recovered when mimicking endoderm environment by cultivation with the condition medium from a visceral endoderm-like cell line, END-2. These results reveal that the miR-125b/Lin28 axis is an important regulator of early lineage specification and cardiomyocyte differentiation of ESCs.

  2. Key Signaling Events for Committing Mouse Pluripotent Stem Cells to the Germline Fate.

    Science.gov (United States)

    Wang, Jian-Qi; Cao, Wen-Guang

    2016-01-01

    The process of germline development carries genetic information and preparatory totipotency across generations. The last decade has witnessed remarkable successes in the generation of germline cells from mouse pluripotent stem cells, especially induced germline cells with the capacity for producing viable offspring, suggesting clinical applications of induced germline cells in humans. However, to date, the culture systems for germline induction with accurate sex-specific meiosis and epigenetic reprogramming have not been well-established. In this study, we primarily focus on the mouse model to discuss key signaling events for germline induction. We review mechanisms of competent regulators on primordial germ cell induction and discuss current achievements and difficulties in inducing sex-specific germline development. Furthermore, we review the developmental identities of mouse embryonic stem cells and epiblast stem cells under certain defined culture conditions as it relates to the differentiation process of becoming germline cells.

  3. Nuclear GAPDH: changing the fate of Müller cells in diabetes

    OpenAIRE

    Jayaguru, Prathiba; Mohr, Susanne

    2012-01-01

    Müller cells, the primary glial cells are a crucial component of the retinal tissue performing a wide range of functions including maintaining the blood-retinal barrier. Several studies suggest that diabetes leads to Müller cell dysfunction and loss. The pathophysiology of hyperglycemia-induced cellular injury of Müller cells remains only poorly understood. Recently, the concept that translocation of the predominantly cytosolic glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH...

  4. Nkx2.2 and Nkx2.9 are the key regulators to determine cell fate of branchial and visceral motor neurons in caudal hindbrain.

    Science.gov (United States)

    Jarrar, Wassan; Dias, Jose M; Ericson, Johan; Arnold, Hans-Henning; Holz, Andreas

    2015-01-01

    Cranial motor nerves in vertebrates are comprised of the three principal subtypes of branchial, visceral, and somatic motor neurons, which develop in typical patterns along the anteroposterior and dorsoventral axes of hindbrain. Here we demonstrate that the formation of branchial and visceral motor neurons critically depends on the transcription factors Nkx2.2 and Nkx2.9, which together determine the cell fate of neuronal progenitor cells. Disruption of both genes in mouse embryos results in complete loss of the vagal and spinal accessory motor nerves, and partial loss of the facial and glossopharyngeal motor nerves, while the purely somatic hypoglossal and abducens motor nerves are not diminished. Cell lineage analysis in a genetically marked mouse line reveals that alterations of cranial nerves in Nkx2.2; Nkx2.9 double-deficient mouse embryos result from changes of cell fate in neuronal progenitor cells. As a consequence progenitors of branchiovisceral motor neurons in the ventral p3 domain of hindbrain are transformed to somatic motor neurons, which use ventral exit points to send axon trajectories to their targets. Cell fate transformation is limited to the caudal hindbrain, as the trigeminal nerve is not affected in double-mutant embryos suggesting that Nkx2.2 and Nkx2.9 proteins play no role in the development of branchiovisceral motor neurons in hindbrain rostral to rhombomere 4.

  5. Traffic jam functions in a branched pathway from Notch activation to niche cell fate.

    Science.gov (United States)

    Wingert, Lindsey; DiNardo, Stephen

    2015-07-01

    The niche directs key behaviors of its resident stem cells, and is thus crucial for tissue maintenance, repair and longevity. However, little is known about the genetic pathways that guide niche specification and development. The male germline stem cell niche in Drosophila houses two stem cell populations and is specified within the embryonic gonad, thus making it an excellent model for studying niche development. The hub cells that form the niche are specified early by Notch activation. Over the next few hours, these individual cells then cluster together and take up a defined position before expressing markers of hub cell differentiation. This timing suggests that there are other factors for niche development yet to be defined. Here, we have identified a role for the large Maf transcription factor Traffic jam (Tj) in hub cell specification downstream of Notch. Tj downregulation is the first detectable effect of Notch activation in hub cells. Furthermore, Tj depletion is sufficient to generate ectopic hub cells that can recruit stem cells. Surprisingly, ectopic niche cells in tj mutants remain dispersed in the absence of Notch activation. This led us to uncover a branched pathway downstream of Notch in which Bowl functions to direct hub cell assembly in parallel to Tj downregulation.

  6. 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...

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

    Directory of Open Access Journals (Sweden)

    Christopher M Penton

    Full Text Available 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.

  8. The thick aleurone1 mutant defines a negative regulation of maize aleurone cell fate that functions downstream of defective kernel1.

    Science.gov (United States)

    Yi, Gibum; Lauter, Adrienne M; Scott, M Paul; Becraft, Philip W

    2011-08-01

    The maize (Zea mays) aleurone layer occupies the single outermost layer of the endosperm. The defective kernel1 (dek1) gene is a central regulator required for aleurone cell fate specification. dek1 mutants have pleiotropic phenotypes including lack of aleurone cells, aborted embryos, carotenoid deficiency, and a soft, floury endosperm deficient in zeins. Here we describe the thick aleurone1 (thk1) mutant that defines a novel negative function in the regulation of aleurone differentiation. Mutants possess multiple layers of aleurone cells as well as aborted embryos. Clonal sectors of thk1 mutant tissue in otherwise normal endosperm showed localized expression of the phenotype with sharp boundaries, indicating a localized cellular function for the gene. Sectors in leaves showed expanded epidermal cell morphology but the mutant epidermis generally remained in a single cell layer. Double mutant analysis indicated that the thk1 mutant is epistatic to dek1 for several aspects of the pleiotropic dek1 phenotype. dek1 mutant endosperm that was mosaic for thk1 mutant sectors showed localized patches of multilayered aleurone. Localized sectors were surrounded by halos of carotenoid pigments and double mutant kernels had restored zein profiles. In sum, loss of thk1 function restored the ability of dek1 mutant endosperm to accumulate carotenoids and zeins and to differentiate aleurone. Therefore the thk1 mutation defines a negative regulator that functions downstream of dek1 in the signaling system that controls aleurone specification and other aspects of endosperm development. The thk1 mutation was found to be caused by a deletion of approximately 2 megabases.

  9. The effects of poly(dimethylsiloxane) surface silanization on the mesenchymal stem cell fate.

    Science.gov (United States)

    Chuah, Yon Jin; Kuddannaya, Shreyas; Lee, Min Hui Adeline; Zhang, Yilei; Kang, Yuejun

    2015-02-01

    In recent years, poly(dimethylsiloxane) (PDMS)-based microfluidic devices have become very popular for on-chip cell investigation. Maintenance of mammalian cell adhesion on the substrate surface is crucial in determining the cell viability, proliferation and differentiation. However, the inherent hydrophobicity of PDMS is unfavourable for cell culture, causing cells to eventually dislodge from the surface. Although physically adsorbed matrix proteins can promote initial cell adhesion, this effect is usually short-lived. To address this critical issue, in this study, we employed (3-aminopropyl) triethoxy silane (APTES) and cross-linker glutaraldehyde (GA) chemistry to immobilize collagen type 1 (Col1) on PDMS. These modified surfaces are highly efficient to support the adhesion of mesenchymal stem cells (MSCs) with no deterioration of their potency. Significant changes of the native PDMS surface properties were observed with the proposed surface functionalization, and MSC adhesion was improved on PDMS surfaces modified with APTES + GA + Protein. Therefore, this covalent surface modification could generate a more biocompatible platform for stabilized cell adhesion. Furthermore, this modification method facilitated long-term cell attachment, which is favourable for successful induction of osteogenesis and cell sheet formation with an increased expression of osteogenic biomarkers and comparable extracellular matrix (ECM) constituent biomarkers, respectively. The surface silanization can be applied to PDMS-based microfluidic systems for long-term study of cellular development. Similar strategies could also be applied to several other substrate materials by appropriate combinations of self-assembled monolayers (SAMs) and ECM proteins.

  10. Hair cell regeneration or the expression of related factors that regulate the fate specification of supporting cells in the cochlear ducts of embryonic and posthatch chickens.

    Science.gov (United States)

    Jiang, Lingling; Jin, Ran; Xu, Jincao; Ji, Yubin; Zhang, Meiguang; Zhang, Xuebo; Zhang, Xinwen; Han, Zhongming; Zeng, Shaoju

    2016-02-01

    Hair cells in posthatch chickens regenerate spontaneously through mitosis or the transdifferentiation of supporting cells in response to antibiotic injury. However, how embryonic chicken cochleae respond to antibiotic treatment remains unknown. This study is the first to indicate that unlike hair cells in posthatch chickens, the auditory epithelium was free from antibiotic injury (25-250 mg gentamicin/kg) in embryonic chickens, although FITC-conjugated gentamicin actually reached embryonic hair cells. Next, we examined and counted the cells and performed labeling for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) (triple or double labeling) in the injured cochlea ducts after gentamicin treatment at 2 h (h), 15 h, 24 h, 2 days (d), 3 d and 7 d after BrdU treatment in posthatch chickens. Our results indicated that following gentamicin administration, proliferating cells (BrdU+) were labeled for Atoh1/Math1 in the damaged areas 3d after gentamicin administration, whereas hair cells (PV+) renewed through mitosis (BrdU+) or direct transdifferentiation (BrdU-) were evident only after 5 d of gentamicin administration. In addition, Sox2 expression was up-regulated in triggered supporting cells at an early stage of regeneration, but stopped at the advent of mature hair cells. Our study also indicated that p27(kip1) was expressed in both hair cells and supporting cells but was down-regulated in a subgroup of the supporting cells that gave rise to hair cells. These data and the obtained dynamic changes of the cells labeled for BrdU, Sox2, Atoh1/Math1, PV or p27(kip1) are useful for understanding supporting cell behaviors and their fate specification during hair cell regeneration.

  11. 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

    Directory of Open Access Journals (Sweden)

    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.

  12. 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.

    Science.gov (United States)

    She, Wenjing; Baroux, Célia

    2015-01-01

    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 (PMC) committed to meiosis takes place in the sporogenous tissue in anther locules and marks the somatic-to-reproductive cell fate transition toward the male reproductive lineage. Here we show that Arabidopsis PMC 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 (MMC). This indicates that chromatin reprogramming is a common underlying scenario in the somatic-to-reproductive cell fate transition in both male and female lineages.

  13. Stimulus-triggered Fate Conversion of Somatic Cells into Pluripotency in Chronic Wounds in Human Beings?

    Directory of Open Access Journals (Sweden)

    Basavraj S. Nagoba

    2015-10-01

    Full Text Available Bone-marrow derived stem cells are multi potential or totipotent and are able to differentiate into numerous cell types. Their application is indicated in various reconstructive and restorative surgeries for rapid healing. A technique for creating cells that have the embryonic ability to turn into almost any cell type in the mammalian body has been reported. Recently, an unexpected phenomenon of somatic cell reprogramming into pluripotent cells by exposing to sublethal stimuli such as citrate based acidic medium has been reported. With the concept of creating acidic environment in chronic infected wounds to make a condition unsuitable for growth and multiplication of bacteria using 3% citric acid has been reported. It would be interesting to study whether the phenomenon of pluripotency takes place in chronic infected wounds in human beings following the application of 3% citric acid and plays an important role in formation of healthy granulation tissue.

  14. Hydrogels with tunable stress relaxation regulate stem cell fate and activity

    Science.gov (United States)

    Chaudhuri, Ovijit; Gu, Luo; Klumpers, Darinka; Darnell, Max; Bencherif, Sidi A.; Weaver, James C.; Huebsch, Nathaniel; Lee, Hong-Pyo; Lippens, Evi; Duda, Georg N.; Mooney, David J.

    2016-03-01

    Natural extracellular matrices (ECMs) are viscoelastic and exhibit stress relaxation. However, hydrogels used as synthetic ECMs for three-dimensional (3D) culture are typically elastic. Here, we report a materials approach to tune the rate of stress relaxation of hydrogels for 3D culture, independently of the hydrogel's initial elastic modulus, degradation, and cell-adhesion-ligand density. We find that cell spreading, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs) are all enhanced in cells cultured in gels with faster relaxation. Strikingly, MSCs form a mineralized, collagen-1-rich matrix similar to bone in rapidly relaxing hydrogels with an initial elastic modulus of 17 kPa. We also show that the effects of stress relaxation are mediated by adhesion-ligand binding, actomyosin contractility and mechanical clustering of adhesion ligands. Our findings highlight stress relaxation as a key characteristic of cell-ECM interactions and as an important design parameter of biomaterials for cell culture.

  15. UNUSUAL FLORAL ORGANS Controls Meristem Identity and Organ Primordia Fate in Arabidopsis.

    Science.gov (United States)

    Wilkinson, M. D.; Haughn, G. W.

    1995-09-01

    A novel gene that is involved in regulating flower initiation and development has been identified in Arabidopsis. This gene has been designated UNUSUAL FLORAL ORGANS (UFO), with five corresponding nuclear recessive alleles designated ufo[middot]1 to ufo[middot]5. Under short day-length conditions, ufo homozygotes generate more coflorescences than do the wild type, and coflorescences often appear apical to the first floral shoot, resulting in a period of inflorescence development in which regions of floral and coflorescence shoots are produced alternately. ufo enhances the phenotype of weak leafy alleles, and the double mutant Ufo-1 Apetala1-1 produces only coflorescence-like shoots, suggesting that these two genes control different aspects of floral initiation. Floral development was also altered in Ufo plants. Ufo flowers have an altered organ number in all whorls, and organs in the first, second, and third whorls exhibit variable homeotic transformations. Ufo single and double mutant phenotypes suggest that the floral changes result from reduction in class B floral homeotic gene expression and fluctuations in the expression boundaries of class C function and FLO10. Surprisingly, in situ hybridization analysis revealed no obvious differences in expression pattern or level in developing Ufo flowers compared with that of the wild type for any class B or C gene studied. We propose that UFO acts in concert with known floral initiation genes and regulates the domains of floral homeotic gene function.

  16. 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

  17. 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.

  18. Transcriptional profiling of ectoderm specification to keratinocyte fate in human embryonic stem cells.

    Science.gov (United States)

    Tadeu, Ana Mafalda Baptista; Lin, Samantha; Hou, Lin; Chung, Lisa; Zhong, Mei; Zhao, Hongyu; Horsley, Valerie

    2015-01-01

    In recent years, several studies have shed light into the processes that regulate epidermal specification and homeostasis. We previously showed that a broad-spectrum γ-secretase inhibitor DAPT promoted early keratinocyte specification in human embryonic stem cells triggered to undergo ectoderm specification. Here, we show that DAPT accelerates human embryonic stem cell differentiation and induces expression of the ectoderm protein AP2. Furthermore, we utilize RNA sequencing to identify several candidate regulators of ectoderm specification including those involved in epithelial and epidermal development in human embryonic stem cells. Genes associated with transcriptional regulation and growth factor activity are significantly enriched upon DAPT treatment during specification of human embryonic stem cells to the ectoderm lineage. The human ectoderm cell signature identified in this study contains several genes expressed in ectodermal and epithelial tissues. Importantly, these genes are also associated with skin disorders and ectodermal defects, providing a platform for understanding the biology of human epidermal keratinocyte development under diseased and homeostatic conditions.

  19. BDNF and its receptors in human myasthenic thymus: implications for cell fate in thymic pathology.

    Science.gov (United States)

    Berzi, Angela; Ayata, C Korcan; Cavalcante, Paola; Falcone, Chiara; Candiago, Elisabetta; Motta, Teresio; Bernasconi, Pia; Hohlfeld, Reinhard; Mantegazza, Renato; Meinl, Edgar; Farina, Cinthia

    2008-07-15

    Here we show that in myasthenic thymus several cell types, including thymic epithelial cells (TEC) and immune cells, were the source and the target of the neurotrophic factor brain-derived growth factor (BDNF). Interestingly, many actively proliferating medullary thymocytes expressed the receptor TrkB in vivo in involuted thymus, while this population was lost in hyperplastic or neoplastic thymuses. Furthermore, in hyperplastic thymuses the robust coordinated expression of BDNF in the germinal centers together with the receptor p75NTR on all proliferating B cells strongly suggests that this factor regulates germinal center reaction. Finally, all TEC dying of apoptosis expressed BDNF receptors, indicating that this neurotrophin is involved in TEC turnover. In thymomas both BDNF production and receptor expression in TEC were strongly hindered. This may represent an attempt of tumour escape from cell death.

  20. 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.

  1. 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.

  2. 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

    Full Text Available BACKGROUND: 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. METHODOLOGY/PRINCIPAL FINDINGS: 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. CONCLUSIONS/SIGNIFICANCE: 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 Ob

  3. Diverse spatio-temporal dynamical patterns of p53 and cell fate decisions

    Science.gov (United States)

    Clairambault, Jean; Eliaš, Ján

    2016-06-01

    The protein p53 as a tumour suppressor protein accumulates in cells in response to DNA damage and transactivates a large variety of genes involved in apoptosis, cell cycle regulation and numerous other processes. Recent biological observations suggest that specific spatio-temporal dynamical patterns of p53 may be associated with specific cellular response, and thus the spatio-temporal heterogeneity of the p53 dynamics contributes to the overall complexity of p53 signalling. Reaction-diffusion equations taking into account spatial representation of the cell and motion of the species inside the cell can be used to model p53 protein network and could be thus of some help to biologists and pharmacologists in anticancer treatment.

  4. The pentose phosphate pathway: an antioxidant defense and a crossroad in tumor cell fate.

    Science.gov (United States)

    Riganti, Chiara; Gazzano, Elena; Polimeni, Manuela; Aldieri, Elisabetta; Ghigo, Dario

    2012-08-01

    The pentose phosphate pathway, one of the main antioxidant cellular defense systems, has been related for a long time almost exclusively to its role as a provider of reducing power and ribose phosphate to the cell. In addition to this "traditional" correlation, in the past years multiple roles have emerged for this metabolic cascade, involving the cell cycle, apoptosis, differentiation, motility, angiogenesis, and the response to anti-tumor therapy. These findings make the pentose phosphate pathway a very interesting target in tumor cells. This review summarizes the latest discoveries relating the activity of the pentose phosphate pathway to various aspects of tumor metabolism, such as cell proliferation and death, tissue invasion, angiogenesis, and resistance to therapy, and discusses the possibility that drugs modulating the pathway could be used as potential tools in tumor therapy.

  5. Differences in intracellular fate of two spotted fever group Rickettsia in macrophage-like cells

    Directory of Open Access Journals (Sweden)

    Pedro Curto

    2016-07-01

    Full Text Available Spotted fever group (SFG rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (R. conorii and Rocky Mountain spotted fever (R. rickettsii. Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickettsial diseases. These studies raise the hypothesis that the role of macrophages in rickettsial pathogenesis may have been underappreciated. Herein, we evaluated the ability of two SFG rickettsial species, R. conorii (a recognized human pathogen and R. montanensis (a non-virulent member of SFG to proliferate in THP-1 macrophage-like cells, or within non-phagocytic cell lines. Our results demonstrate that R. conorii was able to survive and proliferate in both phagocytic and epithelial cells in vitro. In contrast, R. montanensis was able to grow in non-phagocytic cells, but was drastically compromised in the ability to proliferate within both undifferentiated and PMA-differentiated THP-1 cells. Interestingly, association assays revealed that R. montanensis was defective in binding to THP-1-derived macrophages; however, the invasion of the bacteria that are able to adhere did not appear to be affected. We have also demonstrated that R. montanensis which entered into THP-1-derived macrophages were rapidly destroyed and partially co-localized with LAMP-2 and cathepsin D, two markers of lysosomal compartments. In contrast, R. conorii was present as intact bacteria and free in the cytoplasm in both cell types. These findings suggest that a phenotypic difference between a non-pathogenic and a pathogenic SFG member lies in their respective ability to proliferate in macrophage-like cells, and may provide an explanation as to why certain SFG rickettsial species are not associated with

  6. Origin and fate of hematopoietic stem precursor cells in the leech Hirudo medicinalis

    OpenAIRE

    GRIMALDI, A

    2016-01-01

    The hematopoietic process by which blood cells are formed has been intensely studied for over a century using several model systems. An increasing amount of evidence shows that hematopoiesis, angiogenesis, immune response and the regulating these processes (i.e., cytokines) are highly conserved across taxonomic groups. Over the last decade, the leech Hirudo medicinalis, given its simple anatomy and its repertoire of less varied cell types when compared to vertebrates, has been ...

  7. Differences in Intracellular Fate of Two Spotted Fever Group Rickettsia in Macrophage-Like Cells

    Science.gov (United States)

    Curto, Pedro; Simões, Isaura; Riley, Sean P.; Martinez, Juan J.

    2016-01-01

    Spotted fever group (SFG) rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (Rickettsia conorii) and Rocky Mountain spotted fever (Rickettsia rickettsii). Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickettsial diseases. These studies raise the hypothesis that the role of macrophages in rickettsial pathogenesis may have been underappreciated. Herein, we evaluated the ability of two SFG rickettsial species, R. conorii (a recognized human pathogen) and Rickettsia montanensis (a non-virulent member of SFG) to proliferate in THP-1 macrophage-like cells, or within non-phagocytic cell lines. Our results demonstrate that R. conorii was able to survive and proliferate in both phagocytic and epithelial cells in vitro. In contrast, R. montanensis was able to grow in non-phagocytic cells, but was drastically compromised in the ability to proliferate within both undifferentiated and PMA-differentiated THP-1 cells. Interestingly, association assays revealed that R. montanensis was defective in binding to THP-1-derived macrophages; however, the invasion of the bacteria that are able to adhere did not appear to be affected. We have also demonstrated that R. montanensis which entered into THP-1-derived macrophages were rapidly destroyed and partially co-localized with LAMP-2 and cathepsin D, two markers of lysosomal compartments. In contrast, R. conorii was present as intact bacteria and free in the cytoplasm in both cell types. These findings suggest that a phenotypic difference between a non-pathogenic and a pathogenic SFG member lies in their respective ability to proliferate in macrophage-like cells, and may provide an explanation as to why certain SFG rickettsial species are not associated

  8. Cilia Control Vascular Mural Cell Recruitment in Vertebrates

    Directory of Open Access Journals (Sweden)

    Xiaowen Chen

    2017-01-01

    Full Text Available Vascular mural cells (vMCs are essential components of the vertebrate vascular system, controlling blood vessel maturation and homeostasis. Discrete molecular mechanisms have been associated with vMC development and differentiation. The function of hemodynamic forces in controlling vMC recruitment is unclear. Using transgenic lines marking developing vMCs in zebrafish embryos, we find that vMCs are recruited by arterial-fated vessels and that the process is flow dependent. We take advantage of tissue-specific CRISPR gene targeting to demonstrate that hemodynamic-dependent Notch activation and the ensuing arterial genetic program is driven by endothelial primary cilia. We also identify zebrafish foxc1b as a cilia-dependent Notch-specific target that is required within endothelial cells to drive vMC recruitment. In summary, we have identified a hemodynamic-dependent mechanism in the developing vasculature that controls vMC recruitment.

  9. 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.

  10. miR-600 Acts as a Bimodal Switch that Regulates Breast Cancer Stem Cell Fate through WNT Signaling.

    Science.gov (United States)

    El Helou, Rita; Pinna, Guillaume; Cabaud, Olivier; Wicinski, Julien; Bhajun, Ricky; Guyon, Laurent; Rioualen, Claire; Finetti, Pascal; Gros, Abigaelle; Mari, Bernard; Barbry, Pascal; Bertucci, Francois; Bidaut, Ghislain; Harel-Bellan, Annick; Birnbaum, Daniel; Charafe-Jauffret, Emmanuelle; Ginestier, Christophe

    2017-02-28

    Breast cancer stem cells (bCSCs) have been implicated in tumor progression and therapeutic resistance; however, the molecular mechanisms that define this state are unclear. We have performed two microRNA (miRNA) gain- and loss-of-function screens to identify miRNAs that regulate the choice between bCSC self-renewal and differentiation. We find that micro-RNA (miR)-600 silencing results in bCSC expansion, while its overexpression reduces bCSC self-renewal, leading to decreased in vivo tumorigenicity. miR-600 targets stearoyl desaturase 1 (SCD1), an enzyme required to produce active, lipid-modified WNT proteins. In the absence of miR-600, WNT signaling is active and promotes self-renewal, whereas overexpression of miR-600 inhibits the production of active WNT and promotes bCSC differentiation. In a series of 120 breast tumors, we found that a low level of miR-600 is correlated with active WNT signaling and a poor prognosis. These findings highlight a miR-600-centered signaling network that governs bCSC-fate decisions and influences tumor progression.

  11. miR-600 Acts as a Bimodal Switch that Regulates Breast Cancer Stem Cell Fate through WNT Signaling

    Directory of Open Access Journals (Sweden)

    Rita El Helou

    2017-02-01

    Full Text Available Breast cancer stem cells (bCSCs have been implicated in tumor progression and therapeutic resistance; however, the molecular mechanisms that define this state are unclear. We have performed two microRNA (miRNA gain- and loss-of-function screens to identify miRNAs that regulate the choice between bCSC self-renewal and differentiation. We find that micro-RNA (miR-600 silencing results in bCSC expansion, while its overexpression reduces bCSC self-renewal, leading to decreased in vivo tumorigenicity. miR-600 targets stearoyl desaturase 1 (SCD1, an enzyme required to produce active, lipid-modified WNT proteins. In the absence of miR-600, WNT signaling is active and promotes self-renewal, whereas overexpression of miR-600 inhibits the production of active WNT and promotes bCSC differentiation. In a series of 120 breast tumors, we found that a low level of miR-600 is correlated with active WNT signaling and a poor prognosis. These findings highlight a miR-600-centered signaling network that governs bCSC-fate decisions and influences tumor progression.

  12. Tracing anti-cancer and cancer-promoting actions of all-trans retinoic acid in breast cancer to a RARα epigenetic mechanism of mammary epithelial cell fate.

    Science.gov (United States)

    Rossetti, Stefano; Ren, MingQiang; Visconti, Nicolo; Corlazzoli, Francesca; Gagliostro, Vincenzo; Somenzi, Giulia; Yao, Jin; Sun, Yijun; Sacchi, Nicoletta

    2016-12-27

    A hallmark of cancer cells is the ability to evade the growth inhibitory/pro-apoptotic action of physiological all-trans retinoic acid (RA) signal, the bioactive derivative of Vitamin A. However, as we and others reported, RA can also promote cancer cell growth and invasion. Here we show that anticancer and cancer-promoting RA actions in breast cancer have roots in a mechanism of mammary epithelial cell morphogenesis that involves both transcriptional (epigenetic) and non-transcriptional RARα (RARA) functions. We found that the mammary epithelial cell-context specific degree of functionality of the RARA transcriptional (epigenetic) component of this mechanism, by tuning the effects of the non-transcriptional RARA component, determines different cell fate decisions during mammary morphogenesis. Indeed, factors that hamper the RARA epigenetic function make physiological RA drive aberrant morphogenesis via non-transcriptional RARA, thus leading to cell transformation. Remarkably, also the cell context-specific degree of functionality of the RARA epigenetic component retained by breast cancer cells is critical to determine cell fate decisions in response to physiological as well as supraphysiological RA variation. Overall this study supports the proof of principle that the epigenetic functional plasticity of the mammary epithelial cell RARA mechanism, which is essential for normal morphogenetic processes, is necessary to deter breast cancer onset/progression consequent to the insidious action of physiological RA.

  13. 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.

  14. [Master Transcription Regulators Specifying Cell-Lineage Fates in Development As Possible Therapeutic Targets in Oncology].

    Science.gov (United States)

    Kondratyeva, L G; Vinogradova, T V; Chernov, I P; Sverdlov, E D

    2015-11-01

    The transformation of normal precursors into cancer cells is an intricately regulated, multistep process. The master regulatory genes that play a crucial role in the process of organism development may also play a key role in carcinogenesis. From such a point of view, cancer is not simply a genetic disease that is due to a progressive accumulation of mutation--it is also a disorder of the developmental system of the tissue in which cancer emerges. Master regulators and their genes disturb stem cell differentiation upon mutation and thus may serve as targets for cancer therapy, in addition to the classic oncogenes and suppressors of tumor formation. This review is an attempt to give a modern concept of master genes and their functions in adult stem cells of the organism and in carcinogenesis, with pancreatic cancer as an example.

  15. Distinct host cell fates for human malignant melanoma targeted by oncolytic rodent parvoviruses.

    Science.gov (United States)

    Vollmers, Ellen M; Tattersall, Peter

    2013-11-01

    The rodent parvoviruses are known to be oncoselective, and lytically infect many transformed human cells. Because current therapeutic regimens for metastatic melanoma have low response rates and have little effect on improving survival, this disease is a prime candidate for novel approaches to therapy, including oncolytic parvoviruses. Screening of low-passage, patient-derived melanoma cell lines for multiplicity-dependent killing by a panel of five rodent parvoviruses identified LuIII as the most melanoma-lytic. This property was mapped to the LuIII capsid gene, and an efficiently melanoma tropic chimeric virus shown to undergo three types of interaction with primary human melanoma cells: (1) complete lysis of cultures infected at very low multiplicities; (2) acute killing resulting from viral protein synthesis and DNA replication, without concomitant expansion of the infection, due to failure to export progeny virions efficiently; or (3) complete resistance that operates at an intracellular step following virion uptake, but preceding viral transcription.

  16. The autophagic- lysosomal pathway determines the fate of glial cells under manganese- induced oxidative stress conditions.

    Science.gov (United States)

    Gorojod, R M; Alaimo, A; Porte Alcon, S; Pomilio, C; Saravia, F; Kotler, M L

    2015-10-01

    Manganese (Mn) overexposure is frequently associated with the development of a neurodegenerative disorder known as Manganism. The Mn-mediated generation of reactive oxygen species (ROS) promotes cellular damage, finally leading to apoptotic cell death in rat astrocytoma C6 cells. In this scenario, the autophagic pathway could play an important role in preventing cytotoxicity. In the present study, we found that Mn induced an increase in the amount and total volume of acidic vesicular organelles (AVOs), a process usually related to the activation of the autophagic pathway. Particularly, the generation of enlarged AVOs was a ROS- dependent event. In this report we demonstrated for the first time that Mn induces autophagy in glial cells. This conclusion emerged from the results obtained employing a battery of autophagy markers: a) the increase in LC3-II expression levels, b) the formation of autophagic vesicles labeled with monodansylcadaverine (MDC) or LC3 and, c) the increase in Beclin 1/ Bcl-2 and Beclin 1/ Bcl-X(L) ratio. Autophagy inhibition employing 3-MA and mAtg5(K130R) resulted in decreased cell viability indicating that this event plays a protective role in Mn- induced cell death. In addition, mitophagy was demonstrated by an increase in LC3 and TOM-20 colocalization. On the other hand, we proposed the occurrence of lysosomal membrane permeabilization (LMP) based in the fact that cathepsins B and D activities are essential for cell death. Both cathepsin B inhibitor (Ca-074 Me) or cathepsin D inhibitor (Pepstatin A) completely prevented Mn- induced cytotoxicity. In addition, low dose of Bafilomycin A1 showed a similar effect, a finding that adds evidence about the lysosomal role in Mn cytotoxicity. Finally, in vivo experiments demonstrated that Mn induces injury and alters LC3 expression levels in rat striatal astrocytes. In summary, our results demonstrated that autophagy is activated to counteract the harmful effect caused by Mn. These data is valuable to

  17. Transport across the cell-membrane dictates nanoparticle fate and toxicity: a new paradigm in nanotoxicology

    Science.gov (United States)

    Guarnieri, Daniela; Sabella, Stefania; Muscetti, Ornella; Belli, Valentina; Malvindi, Maria Ada; Fusco, Sabato; de Luca, Elisa; Pompa, Pier Paolo; Netti, Paolo A.

    2014-08-01

    The toxicity of metallic nanoparticles (MNPs) has been fully ascertained, but the mechanisms underlying their cytotoxicity remain still largely unclear. Here we demonstrate that the cytotoxicity of MNPs is strictly reliant on the pathway of cellular internalization. In particular, if otherwise toxic gold, silver, and iron oxide NPs are forced through the cell membrane bypassing any form of active mechanism (e.g., endocytosis), no significant cytotoxic effect is registered. Pneumatically driven NPs across the cell membrane show a different distribution within the cytosol compared to NPs entering the cell by active endocytosis. Specifically, they exhibit free random Brownian motions within the cytosol and do not accumulate in lysosomes. Results suggest that intracellular accumulation of metallic nanoparticles into endo-lysosomal compartments is the leading cause of nanotoxicity, due to consequent nanoparticle degradation and in situ release of metal ions.The toxicity of metallic nanoparticles (MNPs) has been fully ascertained, but the mechanisms underlying their cytotoxicity remain still largely unclear. Here we demonstrate that the cytotoxicity of MNPs is strictly reliant on the pathway of cellular internalization. In particular, if otherwise toxic gold, silver, and iron oxide NPs are forced through the cell membrane bypassing any form of active mechanism (e.g., endocytosis), no significant cytotoxic effect is registered. Pneumatically driven NPs across the cell membrane show a different distribution within the cytosol compared to NPs entering the cell by active endocytosis. Specifically, they exhibit free random Brownian motions within the cytosol and do not accumulate in lysosomes. Results suggest that intracellular accumulation of metallic nanoparticles into endo-lysosomal compartments is the leading cause of nanotoxicity, due to consequent nanoparticle degradation and in situ release of metal ions. Electronic supplementary information (ESI) available. See DOI

  18. Origin and fate of hematopoietic stem precursor cells in the leech Hirudo medicinalis

    Directory of Open Access Journals (Sweden)

    A Grimaldi

    2016-07-01

    Full Text Available The hematopoietic process by which blood cells are formed has been intensely studied for over a century using several model systems. An increasing amount of evidence shows that hematopoiesis, angiogenesis, immune response and the regulating these processes (i.e., cytokines are highly conserved across taxonomic groups. Over the last decade, the leech Hirudo medicinalis, given its simple anatomy and its repertoire of less varied cell types when compared to vertebrates, has been proposed as a powerful model for studying basic steps of hematopoiesis and immune responses. Here, I provide a broad overview of H. medicinalis hematopoiesis and I highlight the benefits of using leech as a model.

  19. 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......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...

  20. 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.

  1. TBX1 Represses Vegfr2 Gene Expression and Enhances the Cardiac Fate of VEGFR2+ Cells

    Science.gov (United States)

    Lania, Gabriella; Ferrentino, Rosa; Baldini, Antonio

    2015-01-01

    The T-box transcription factor TBX1 has critical roles in maintaining proliferation and inhibiting differentiation of cardiac progenitor cells of the second heart field (SHF). Haploinsufficiency of the gene that encodes it is a cause of congenital heart disease. Here, we developed an embryonic stem (ES) cell-based model in which Tbx1 expression can be modulated by tetracycline. Using this model, we found that TBX1 down regulates the expression of VEGFR2, and we confirmed this finding in vivo during embryonic development. In addition, we found a Vegfr2 domain of expression, not previously described, in the posterior SHF and this expression is extended by loss of Tbx1. VEGFR2 has been previously described as a marker of a subpopulation of cardiac progenitors. Clonal analysis of ES-derived VEGFR2+ cells indicated that 12.5% of clones expressed three markers of cardiac lineage (cardiomyocyte, smooth muscle and endothelium). However, a pulse of Tbx1 expression was sufficient to increase the percentage to 20.8%. In addition, the percentage of clones expressing markers of multiple cardiac lineages increased from 41.6% to 79.1% after Tbx1 pulse. These results suggest that TBX1 plays a role in maintaining a progenitor state in VEGFR2+ cells. PMID:26382615

  2. Construction of a fucoidan/laminin functional multilayer to direction vascular cell fate and promotion hemocompatibility.

    Science.gov (United States)

    Ye, Changrong; Wang, Yan; Su, Hong; Yang, Ping; Huang, Nan; F Maitz, Manfred; Zhao, Anshan

    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.

  3. 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.

  4. The Notch-target gene hairy2a impedes the involution of notochordal cells by promoting floor plate fates in Xenopus embryos.

    Science.gov (United States)

    López, Silvia L; Rosato-Siri, María V; Franco, Paula G; Paganelli, Alejandra R; Carrasco, Andrés E

    2005-03-01

    We have previously shown that the early Xenopus organiser contains cells equally potent to give rise to notochord or floor plate, and that Notch signalling triggers a binary decision, favouring the floor plate fate at the expense of the notochord. Now, we present evidence that Delta1 is the ligand that triggers the binary switch, which is executed through the Notch-mediated activation of hairy2a in the surrounding cells within the organiser, impeding their involution through the blastopore and promoting their incorporation into the hairy2a+ notoplate precursors (future floor-plate cells) in the dorsal non-involuting marginal zone.

  5. 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.

  6. 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

    Macrophages (MPs) exert either beneficial or deleterious effects on tissue repair, depending on their activation/polarization state. They are crucial for adult skeletal muscle repair, notably by acting on myogenic precursor cells. However, these interactions have not been fully characterized. Here......, 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...

  7. Differences in Intracellular Fate of Two Spotted Fever Group Rickettsia in Macrophage-Like Cells

    OpenAIRE

    Pedro Curto; Isaura Simoes; Riley, Sean P; Juan Jose Martinez

    2016-01-01

    Spotted fever group (SFG) rickettsiae are recognized as important agents of human tick-borne diseases worldwide, such as Mediterranean spotted fever (Rickettsia conorii) and Rocky Mountain spotted fever (Rickettsia rickettsii). Recent studies in several animal models have provided evidence of non-endothelial parasitism by pathogenic SFG Rickettsia species, suggesting that the interaction of rickettsiae with cells other than the endothelium may play an important role in pathogenesis of rickett...

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

    OpenAIRE

    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 maintena...

  9. The Caenorhabditis elegans Excretory System: A Model for Tubulogenesis, Cell Fate Specification, and Plasticity.

    Science.gov (United States)

    Sundaram, Meera V; Buechner, Matthew

    2016-05-01

    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.

  10. Fate of 3H-thymidine labelled myogenic cells in regeneration of muscle isografts.

    Science.gov (United States)

    Gutmann, E; Mares, V; Stichová, J

    1976-03-05

    Intact and denervated extensor digitorum longus (EDL) muscles of 20-day-old inbred Lewis-Wistar rats were labelled with 3H-thymidine. Ninety minutes after the injection of the isotope 4.0% of the nuclei were labelled in the intact (i.e. innervated) and 9.6% in the muscles, denervated 3 days before administration of the isotope. The labelled EDL muscles were grafted into the bed of the previously removed EDL muscles of inbred animals and these isografts were studied 30 days later. In the EDL muscles, regenerated from innervated isografts only occasionally labelled endothelial cells were found whereas in the muscles regenerated from denervated isografts also parenchymal muscle nuclei were regularly labelled. The incidence of labelled nuclei in the regenerated EDL muscles was, however, about 20 times lower than in the donor EDL muscles. The presen experiments provide a direct proof of utilization of donor satelite cell nuclei for regeneration in grafted muscle tissue. With respect to the low incidence of labelled nuclei in regenerated EDL muscles, other sources of cells apparently also contribute to the regeneration process.

  11. Long-term fate of glyphosate associated with repeated rodeo applications to control smooth cordgrass (Spartina alterniflora) in Willapa Bay, Washington.

    Science.gov (United States)

    Kilbride, K M; Paveglio, F L

    2001-02-01

    Cordgrasses (Spartina sp.) are exotic, invasive species that threaten to degrade the intertidal zones of estuaries along the West Coast of North America. Integrated pest management (IPM) strategies primarily focus on the use of aerial and ground applications of Rodeo in conjunction with mowing, but IPM treatments over multiple years usually are necessary to control Spartina. Although information exists regarding the short-term fate and effects to marine biota of a single Rodeo application to control Spartina, little information is available regarding the fate and biotic effects associated with repeated Rodeo applications necessary for control. Consequently, we conducted a 3-year study to assess the short- and long-term fate and potential effects to marine biota associated with repeated applications of Rodeo to control smooth cordgrass in a southwestern Washington estuary. At each of three intertidal locations in Willapa Bay, we established plots on exposed mudflats and along the edge of a Spartina meadow that were hand sprayed with Rodeo (5% solution) and LI-700 (2% solution) during July 1997 and 1998. Glyphosate concentrations in sediment from mudflat plots declined 88% to 96% from 1 day posttreatment in 1997 to 1 year after the second Rodeo applications in 1999. In contrast, glyphosate concentrations in Spartina plots increased 231% to 591% from 1997 to 1999 because Spartina rhizomes likely did not readily metabolize or exude it. Comparison of concentrations from mudflat and Spartina plots with toxicity test values for marine biota indicates that under worst-case conditions short- and long-term detrimental effects to aquatic biota from repeated application of Rodeo for Spartina control would be highly unlikely.

  12. 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.

  13. Range and stability of cell fate determination in isolated sea urchin blastomeres.

    Science.gov (United States)

    Livingston, B T; Wilt, F H

    1990-03-01

    We have examined the developmental potential of blastomeres isolated from either the animal (mesomeres) or vegetal (macromeres-micromeres) half of 16-cell embryos of the sea urchin Lytechinus pictus. We have also examined the effects of two known vegetalizing agents on the development of isolated mesomeres; LiCl treatment and combination with micromeres, the small blastomeres found at the vegetal pole of the 16-cell embryo. The markers for differentiation used were both morphological (invaginations, spicules and pigment cells) and molecular (gut-specific alkaline phosphatase activity, and monoclonal antibodies against antigens specific for gut and oral ectoderm). Embryoids derived from isolated mesomeres expressed markers characteristic of vegetal differentiation only at very low levels. They did express an antigen characteristic of animal development, the oral ectoderm antigen, but with an altered pattern. Isolated macromere-micromere pairs expressed all markers characteristic of vegetal development, but did not express the marker characteristic of animal development. Increasing concentrations of LiCl caused isolated mesomeres to give rise to embryoids with an increasing tendency to express vegetal markers of differentiation, and it was found that expression of different vegetal markers begin to appear at different concentrations of LiCl. LiCl also caused the marker for oral ectoderm to be expressed in a more normal pattern. Combining micromeres with mesomeres also induced mesomere derivatives to differentiate in a vegetal manner. Micromeres were not completely effective in inducing a more normal pattern of expression of the marker for oral ectoderm. The treatment of isolated mesomeres with both LiCl and micromeres produces a synergistic effect resulting in embryoids expressing markers not induced by either treatment alone.

  14. ICSI choreography: fate of sperm structures after monospermic rhesus ICSI and first cell cycle implications.

    Science.gov (United States)

    Ramalho-Santos, J; Sutovsky, P; Simerly, C; Oko, R; Wessel, G M; Hewitson, L; Schatten, G

    2000-12-01

    We have dissected the initial stages of fertilization by intracytoplasmic sperm injection of single spermatozoa into prime oocytes from fertile rhesus monkeys (Macaca mulatta). DNA decondensation was delayed at the apical portion of the sperm head. It is possible that this asynchronous male DNA decondensation could be related to the persistence of the sperm acrosome and perinuclear theca after injection. However, incomplete male pronuclear formation did not prevent sperm aster formation, microtubule nucleation and pronuclear apposition. In contrast, DNA synthesis was delayed in both pronuclei until the sperm chromatin fully decondensed, indicating that male pronuclear formation constitutes an important checkpoint during the first embryonic cell cycle.

  15. CXCR4 signaling regulates radial glial morphology and cell fate during embryonic spinal cord development.

    Science.gov (United States)

    Mithal, Divakar S; Ren, Dongjun; Miller, Richard J

    2013-08-01

    Embryonic meninges secrete the chemokine SDF-1/CXCL12 as a chemotactic guide for migrating neural stem cells, but SDF-1 is not known to directly regulate the functions of radial glia. Recently, the developing meninges have been shown to regulate radial glial function, yet the mechanisms and signals responsible for this phenomenon remain unclear. Moreover, as a nonmigratory cell type, radial glia do not conform to traditional models associated with chemokine signaling in the central nervous system. Using fluorescent transgenes, in vivo genetic manipulations and pharmacological techniques, we demonstrate that SDF-1 derived from the meninges exerts a CXCR4-dependent effect on radial glia. Deletion of CXCR4 expression by radial glia influences their morphology, mitosis, and progression through both oligodendroglial and astroglial lineages. Additionally, disruption of CXCR4 signaling in radial glia has a transient effect on the migration of oligodendrocyte progenitors. These data indicate that a specific chemokine signal derived from the meninges has multiple regulatory effects on radial glia.

  16. 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.

  17. Diverse fates of uracilated HIV-1 DNA during infection of myeloid lineage cells

    Science.gov (United States)

    Hansen, Erik C; Ransom, Monica; Hesselberth, Jay R; Hosmane, Nina N; Capoferri, Adam A; Bruner, Katherine M; Pollack, Ross A; Zhang, Hao; Drummond, Michael Bradley; Siliciano, Janet M; Siliciano, Robert; Stivers, James T

    2016-01-01

    We report that a major subpopulation of monocyte-derived macrophages (MDMs) contains high levels of dUTP, which is incorporated into HIV-1 DNA during reverse transcription (U/A pairs), resulting in pre-integration restriction and post-integration mutagenesis. After entering the nucleus, uracilated viral DNA products are degraded by the uracil base excision repair (UBER) machinery with less than 1% of the uracilated DNA successfully integrating. Although uracilated proviral DNA showed few mutations, the viral genomic RNA was highly mutated, suggesting that errors occur during transcription. Viral DNA isolated from blood monocytes and alveolar macrophages (but not T cells) of drug-suppressed HIV-infected individuals also contained abundant uracils. The presence of viral uracils in short-lived monocytes suggests their recent infection through contact with virus producing cells in a tissue reservoir. These findings reveal new elements of a viral defense mechanism involving host UBER that may be relevant to the establishment and persistence of HIV-1 infection. DOI: http://dx.doi.org/10.7554/eLife.18447.001 PMID:27644592

  18. Contrasting distributions of groundwater arsenic and uranium in the western Hetao basin, Inner Mongolia: Implication for origins and fate controls

    Science.gov (United States)

    Guo, Huaming; Jia, Yongfeng; Wanty, Richard B.; Jiang, Yuxiao; Zhao, Weiguang; Xiu, Wei; Shen, Jiaxing; Li, Yuan; Cao, Yongsheng; Wu, Yang; Zhang, Di; Wei, Chao; Zhang, Yilong; Cao, Wengeng; Foster, Andrea L.

    2016-01-01

    Although As concentrations have been investigated in shallow groundwater from the Hetao basin, China, less is known about U and As distributions in deep groundwater, which would help to better understand their origins and fate controls. Two hundred and ninety-nine groundwater samples, 122 sediment samples, and 14 rock samples were taken from the northwest portion of the Hetao basin, and analyzed for geochemical parameters. Results showed contrasting distributions of groundwater U and As, with high U and low As concentrations in the alluvial fans along the basin margins, and low U and high As concentrations downgradient in the flat plain. The probable sources of both As and U in groundwater were ultimately traced to the bedrocks in the local mountains (the Langshan Mountains). Chemical weathering of U-bearing rocks (schist, phyllite, and carbonate veins) released and mobilized U as UO2(CO3)22 − and UO2(CO3)34 − species in the alluvial fans under oxic conditions and suboxic conditions where reductions of Mn and NO3− were favorable (OSO), resulting in high groundwater U concentrations. Conversely, the recent weathering of As-bearing rocks (schist, phyllite, and sulfides) led to the formation of As-bearing Fe(III) (hydr)oxides in sediments, resulting in low groundwater As concentrations. Arsenic mobilization and U immobilization occurred in suboxic conditions where reduction of Fe(III) oxides was favorable and reducing conditions (SOR). Reduction of As-bearing Fe(III) (hydr)oxides, which were formed during palaeo-weathering and transported and deposited as Quaternary aquifer sediments, was believed to release As into groundwater. Reduction of U(VI) to U(IV) would lead to the formation of uraninite, and therefore remove U from groundwater. We conclude that the contrasting distributions of groundwater As and U present a challenge to ensuring safe drinking water in analogous areas, especially with high background values of U and As.

  19. 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.

  20. Hepatocyte growth factor activator inhibitor-1 is induced by bone morphogenetic proteins and regulates proliferation and cell fate of neural progenitor cells.

    Directory of Open Access Journals (Sweden)

    Raili Koivuniemi

    Full Text Available BACKGROUND: Neural progenitor cells (NPCs in the developing neuroepithelium are regulated by intrinsic and extrinsic factors. There is evidence that NPCs form a self-supporting niche for cell maintenance and proliferation. However, molecular interactions and cell-cell contacts and the microenvironment within the neuroepithelium are largely unknown. We hypothesized that cellular proteases especially those associated with the cell surface of NPCs play a role in regulation of progenitor cells in the brain. METHODOLOGY/PRINCIPAL FINDINGS: In this work, we show that NPCs, isolated from striatal anlage of developing rat brain, express hepatocyte growth factor activator inhibitor-1 and -2 (HAI-1 and HAI-2 that are cell surface-linked serine protease inhibitors. In addition, radial glia cells derived from mouse embryonic stem cells also express HAI-1 and HAI-2. To study the functional significance of HAI-1 and HAI-2 in progenitor cells, we modulated their levels using expression plasmids or silencing RNA (siRNA transfected into the NPCs. Data showed that overexpression of HAI-1 or HAI-2 decreased cell proliferation of cultured NPCs, whilst their siRNAs had opposite effects. HAI-1 also influenced NPC differentiation by increasing the number of glial fibrillary acidic protein (GFAP expressing cells in the culture. Expression of HAI-1 in vivo decreased cell proliferation in developing neuroepithelium in E15 old animals and promoted astrocyte cell differentiation in neonatal animals. Studying the regulation of HAI-1, we observed that Bone morphogenetic protein-2 (BMP-2 and BMP-4 increased HAI-1 levels in the NPCs. Experiments using HAI-1-siRNA showed that these BMPs act on the NPCs partly in a HAI-1-dependent manner. CONCLUSIONS: This study shows that the cell-surface serine protease inhibitors, HAI-1 and HAI-2 influence proliferation and cell fate of NPCs and their expression levels are linked to BMP signaling. Modulation of the levels and actions of HAI-1

  1. Genetic Fate Mapping Identifies Second Heart Field Progenitor Cells As a Source of Adipocytes in Arrhythmogenic Right Ventricular Cardiomyopathy

    Science.gov (United States)

    Lombardi, Raffaella; Dong, Jinjiang; Rodriguez, Gabriela; Bell, Achim; Leung, Tack Ki; Schwartz, Robert J.; Willerson, James T.; Brugada, Ramon; Marian, Ali J.

    2009-01-01

    The phenotypic hallmark of arrhythmogenic right ventricular cardiomyopathy, a genetic disease of desmosomal proteins, is fibroadipocytic replacement of the right ventricle. Cellular origin of excess adipocytes, the responsible mechanism(s) and the basis for predominant involvement of the right ventricle are unknown. We generated 3 sets of lineage tracer mice regulated by cardiac lineage promoters α-myosin heavy chain (αMyHC), Nkx2.5, or Mef2C. We conditionally expressed the reporter enhanced yellow fluorescent protein while concomitantly deleting the desmosomal protein desmoplakin in cardiac myocyte lineages using the Cre-LoxP technique. Lineage tracer mice showed excess fibroadiposis and increased numbers of adipocytes in the hearts. Few adipocytes in the hearts of αMyHC-regulated lineage tracer mice, but the majority of adipocytes in the hearts of Nkx2.5- and Mef2C-regulated lineage tracer mice, expressed enhanced yellow fluorescent protein. In addition, rare cells coexpressed adipogenic transcription factors and the second heart field markers Isl1 and Mef2C in the lineage tracer mouse hearts and in human myocardium from patients with arrhythmogenic right ventricular cardiomyopathy. To delineate the responsible mechanism, we generated transgenic mice expressing desmosomal protein plakoglobin in myocyte lineages. Transgene plakoglobin translocated to nucleus, detected by immunoblotting and immunofluorescence staining and coimmunoprecipitated with Tcf7l2, a canonical Wnt signaling transcription factor. Expression levels of canonical Wnt/Tcf7l2 targets bone morphogenetic protein 7 and Wnt5b, which promote adipogenesis, were increased and expression level of connective tissue growth factor, an inhibitor of adipogenesis, was decreased. We conclude adipocytes in arrhythmogenic right ventricular cardiomyopathy originate from the second heart field cardiac progenitors, which switch to an adipogenic fate because of suppressed canonical Wnt signaling by nuclear

  2. 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

    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...... 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....

  3. {Stable isotope probing of the physical and biological controls that influence the fate and isotopic composition of carbon derived from the terrestrial methane sink }

    Science.gov (United States)

    Maxfield, P. J.; Hornibrook, E. R. C.; Dildar, N.; Evershed, R. P.

    2009-04-01

    Methane oxidizing bacteria (Methanotrophs) occur in every soil order, and are an important sink for atmospheric CH4 in well aerated soils. The quantity of C cycled via methanotrophic bacteria in soils is globally significant (Le Mer et al., 2001) yet the fate of methane derived carbon remains largely unknown and unquantified. There is generally good agreement regarding the magnitude of the soil CH4 sink determined by methane flux measurements and process modeling. More poorly characterised aspects of the soil CH4 sink include: (i) the physical and biological controls that influence the mechanism of CH4 oxidation in soils; (ii) the fate of oxidized CH4 carbon; (iii) the proportion of C from CH4 oxidation that is sequestered as organic C or released as CO2 (iv) the magnitude of kinetic isotope effects (KIEs) associated with high affinity methanotrophy in soils and the potential influence on the stable carbon isotope composition of atmospheric CH4. This research combines multiple stable isotope analytical approaches to investigate the magnitude, mechanism and pathways of the terrestrial methane sink. Principally 13CH4 stable isotope labeling techniques (Stable isotope probing; SIP) have been used to characterize and quantify methanotrophic populations in a range of different soils (Maxfield et al., 2006). Following 13CH4-incubations soil cores were removed for compound-specific C isotope analyses. Identification and quantification of methanotrophs was effectively achieved via the analysis of 13C-labelled phospholipid fatty acids (PLFAs) to link bacterial structure and function. It was also possible to identify the predominant controls influencing the active methanotrophic populations in both grassland and woodland soils (Maxfield et al., 2008). SIP can be combined with further isotopic analyses to facilitate a broader study of methanotroph C uptake and CH4 derived C sequestration. As SIP facilitates taxonomic assignments of the soil microorganisms involved in CH4 C

  4. An in vitro model for the assessment of stem cell fate following implantation within the infarct microenvironment identifies ISL-1 expression as the strongest predictor of c-Kit(+) cardiac progenitor cells' therapeutic potential.

    Science.gov (United States)

    Sullivan, Kelly E; Burns, Laura J; Black, Lauren D

    2015-11-01

    Cell therapy has the potential to drastically improve clinical outcomes for the 1.45 million patients suffering from a myocardial infarction (MI) each year in the U.S. However, the limitations associated with this treatment - including poor engraftment, significant cell death and poor differentiation potential - have prevented its widespread application clinically. To optimize functional improvements provided by transplanted cells, there is a need to develop methods that increase cellular retention and viability, while supporting differentiation and promoting paracrine signaling. Current in vivo models are expensive, difficult to access and manipulate and are time consuming. We have developed an in vitro model of MI which allows for a straightforward, consistent and relatively accurate prediction of cell fate following injection in vivo. The model demonstrated how the infarct environment impairs cellular engraftment and differentiation, but identified an implantation strategy which enhanced cell fate in vitro. Multivariate linear regression identified variables within the model that regulated vascular differentiation potential including oxygen tension, stiffness and cytokine presence, while cardiac differentiation was more accurately predicted by Isl-1 expression in the original cell isolate than any other variable present within the model system. The model highlighted how the cells' sensitivity to the infarct variables varied from line to line, which emphasizes the importance of the model system for the prediction of cell fate on a patient specific basis. Further development of this model system could help predict the clinical efficacy of cardiac progenitor cell therapy at the patient level as well as identify the optimal strategy for cell delivery.

  5. Derivation of male germ cells from ram bone marrow mesenchymal stem cells by three different methods and evaluation of their fate after transplantation into the testis.

    Science.gov (United States)

    Ghasemzadeh-Hasankolaei, Mohammad; Eslaminejad, Mohammadreza Baghaban; Sedighi-Gilani, Mohammadali

    2016-01-01

    Mesenchymal stem cells (MSCs) have the capacity to differentiate into germ cells (GCs). This research, for the first time, has evaluated the fate of in vitro MSC-derived GCs generated by three different induction methods and compared them after transplantation into the testes of rams. Passage-3 ram bone marrow (BM)-MSCs were divided into three treatment groups: (1) 14-d treatment with 10 μM retinoic acid (RA; RA14), (2) 21-d treatment with 10 μM RA (RA21), and (3) 21-d treatment with 10 ng/ml transforming growth factor beta-1 (TGFb1). After confirmation of the existence of germ-like cells in the culture, the treated cells were labeled and transplanted into the testes of ram lambs. After 2 mo, we conducted histological evaluations of the rams' testes. Results showed that in vitro-derived GCs from all treatment groups survived in the testes. Some of these GCs homed at the basement membrane of seminiferous tubules and formed colonies. The homed cells and cell colonies were similar to testicular native spermatogonia and expressed PGP9.5. TGFb1 exhibited the highest efficiency for in vitro production of GCs as well as the highest capability for homing and colony formation in the testes. RA21 was less efficient than TGFb1, particularly in colony formation. RA14 was the weakest group. No further differentiation of the transplanted GCs was observed. From our results, it could be concluded that a 21-d treatment period of BM-MSCs with TGFb1 is the most efficient method for in vitro generation of spermatogonia-like cells that survive, home, and form colonies in the testes.

  6. Chemokines influence the migration and fate of neural precursor cells from the young adult and middle-aged rat subventricular zone.

    Science.gov (United States)

    Gordon, R J; Mehrabi, N F; Maucksch, C; Connor, B

    2012-01-01

    We have previously demonstrated a role for the chemokines MCP-1, MIP-1α and GRO-α in directing subventricular zone (SVZ)-derived neural precursor cell migration towards the site of cell death in the adult rodent brain. However the influence of chemokines such as MCP-1, MIP-1α and GRO-α on the differentiation of adult neural precursor cells has not previously been investigated. Further, as the majority of neurological disorders and injuries occur during ageing, it is important to investigate the effect of chemokines on adult neural precursor cell cultures obtained from the ageing brain. This study therefore examined the effect of MCP-1, MIP-1α and GRO-α on SVZ-derived neural precursor cell differentiation in vitro, and assessed whether precursor cells from the middle-aged rat brain (13 months old) follow the same migratory and differential profile as neural precursor cells obtained from the young adult rat brain (2 months old). We observed that each of the chemokines examined generated differing effects in regards to neuronal or glial differentiation. Further, both MIP-1α and GRO-α increased total cell number, suggesting an effect on precursor cell proliferation and/or survival. In agreement with cultures obtained from young adult brains, SVZ-derived neural precursor cells cultured from the middle-aged brain exhibited chemotactic migration in response to a concentration gradient. These results indicate that the chemokines MCP-1, MIP-1α and GRO-α can influence both the migration and fate choice of SVZ-derived neural precursor cells, as well as promoting cell viability. While a response to each of these chemokines is maintained in the middle-aged brain, a distinct age-related alteration in differential fate can be identified.

  7. Ratio of phosphorylated HSP27 to nonphosphorylated HSP27 biphasically acts as a determinant of cellular fate in gemcitabine-resistant pancreatic cancer cells.

    Science.gov (United States)

    Kang, Dongxu; Choi, Hye Jin; Kang, Sujin; Kim, So Young; Hwang, Yong-Sic; Je, Suyeon; Han, Zhezhu; Kim, Joo-Hang; Song, Jae J

    2015-04-01

    Gemcitabine has been used most commonly as an anticancer drug to treat advanced pancreatic cancer patients. However, intrinsic or acquired resistance of pancreatic cancer to gemcitabine was also developed, which leads to very low five-year survival rates. Here, we investigated whether cellular levels of HSP27 phosphorylation act as a determinant of cellular fate with gemcitabine. In addition we have demonstrated whether HSP27 downregulation effectively could overcome the acquisition of gemcitabine resistance by using transcriptomic analysis. We observed that gemcitabine induced p38/HSP27 phosphorylation and caused acquired resistance. After acquisition of gemcitabine resistance, cancer cells showed higher activity of NF-κB. NF-κB activity, as well as colony formation in gemcitabine-resistant pancreatic cancer cells, was significantly decreased by HSP27 downregulation and subsequent TRAIL treatment, showing that HSP27 was a common network mediator of gemcitabine/TRAIL-induced cell death. After transcriptomic analysis, gene fluctuation after HSP27 downregulation was very similar to that of pancreatic cancer cells susceptible to gemcitabine, and then in opposite position to that of acquired gemcitabine resistance, which makes it possible to downregulate HSP27 to overcome the acquired gemcitabine resistance to function as an overall survival network inhibitor. Most importantly, we demonstrated that the ratio of phosphorylated HSP27 to nonphosphorylated HSP27 rather than the cellular level of HSP27 itself acts biphasically as a determinant of cellular fate in gemcitabine-resistant pancreatic cancer cells.

  8. Embryonic stem cells are redirected to non-tumorigenic epithelial cell fate by interaction with the mammary microenvironment.

    Science.gov (United States)

    Boulanger, Corinne A; Bruno, Robert D; Mack, David L; Gonzales, Monica; Castro, Nadia P; Salomon, David S; Smith, Gilbert H

    2013-01-01

    Experiments were conducted to redirect mouse Embryonic Stem (ES) cells from a tumorigenic phenotype to a normal mammary epithelial phenotype in vivo. Mixing LacZ-labeled ES cells with normal mouse mammary epithelial cells at ratios of 1:5 and 1:50 in phosphate buffered saline and immediately inoculating them into epithelium-divested mammary fat pads of immune-compromised mice accomplished this. Our results indicate that tumorigenesis occurs only when normal mammary ductal growth is not achieved in the inoculated fat pads. When normal mammary gland growth occurs, we find ES cells (LacZ+) progeny interspersed with normal mammary cell progeny in the mammary epithelial structures. We demonstrate that these progeny, marked by LacZ expression, differentiate into multiple epithelial subtypes including steroid receptor positive luminal cells and myoepithelial cells indicating that the ES cells are capable of epithelial multipotency in this context but do not form teratomas. In addition, in secondary transplants, ES cell progeny proliferate, contribute apparently normal mammary progeny, maintain their multipotency and do not produce teratomas.

  9. Embryonic stem cells are redirected to non-tumorigenic epithelial cell fate by interaction with the mammary microenvironment.

    Directory of Open Access Journals (Sweden)

    Corinne A Boulanger

    Full Text Available Experiments were conducted to redirect mouse Embryonic Stem (ES cells from a tumorigenic phenotype to a normal mammary epithelial phenotype in vivo. Mixing LacZ-labeled ES cells with normal mouse mammary epithelial cells at ratios of 1:5 and 1:50 in phosphate buffered saline and immediately inoculating them into epithelium-divested mammary fat pads of immune-compromised mice accomplished this. Our results indicate that tumorigenesis occurs only when normal mammary ductal growth is not achieved in the inoculated fat pads. When normal mammary gland growth occurs, we find ES cells (LacZ+ progeny interspersed with normal mammary cell progeny in the mammary epithelial structures. We demonstrate that these progeny, marked by LacZ expression, differentiate into multiple epithelial subtypes including steroid receptor positive luminal cells and myoepithelial cells indicating that the ES cells are capable of epithelial multipotency in this context but do not form teratomas. In addition, in secondary transplants, ES cell progeny proliferate, contribute apparently normal mammary progeny, maintain their multipotency and do not produce teratomas.

  10. 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

    of radiolabeled microspheres. Using this technique, we have shown that LV-injected tumor cells, in contrast to iv injected tumor cells, were not arrested in the first capillary bed that they encountered but passed viably through the microvasculature of the brain, heart, kidneys, intestinal tract, and to some...

  11. Matrix elasticity of void-forming hydrogels controls transplanted-stem-cell-mediated bone formation

    Science.gov (United States)

    Huebsch, Nathaniel; Lippens, Evi; Lee, Kangwon; Mehta, Manav; Koshy, Sandeep T.; Darnell, Max C.; Desai, Rajiv M.; Madl, Christopher M.; Xu, Maria; Zhao, Xuanhe; Chaudhuri, Ovijit; Verbeke, Catia; Kim, Woo Seob; Alim, Karen; Mammoto, Akiko; Ingber, Donald E.; Duda, Georg N.; Mooney, David J.

    2015-12-01

    The effectiveness of stem cell therapies has been hampered by cell death and limited control over fate. These problems can be partially circumvented by using macroporous biomaterials that improve the survival of transplanted stem cells and provide molecular cues to direct cell phenotype. Stem cell behaviour can also be controlled in vitro by manipulating the elasticity of both porous and non-porous materials, yet translation to therapeutic processes in vivo remains elusive. Here, by developing injectable, void-forming hydrogels that decouple pore formation from elasticity, we show that mesenchymal stem cell (MSC) osteogenesis in vitro, and cell deployment in vitro and in vivo, can be controlled by modifying, respectively, the hydrogel’s elastic modulus or its chemistry. When the hydrogels were used to transplant MSCs, the hydrogel’s elasticity regulated bone regeneration, with optimal bone formation at 60 kPa. Our findings show that biophysical cues can be harnessed to direct therapeutic stem cell behaviours in situ.

  12. The fate of eroded soil organic carbon along a European transect – controls after deposition in terrestrial and aquatic systems

    DEFF Research Database (Denmark)

    Kirkels, Frédérique; Cammeraat, Erik; Kalbitz, Karsten;

    on the fate of SOC such as amounts and composition of soil organic matter (SOM), distribution of SOC in density fractions and aggregates as well as soil physical and chemical properties. NMR analysis provided an in-depth characterization of SOM quality, showing large similarities in chemical composition among...... of eroded SOC takes place on downslope soils within the catchment and in adjacent inland waters, i.e. substantial amounts of SOC are transferred from terrestrial to aquatic ecosystems. However, the net effect on C exchange between soils, atmosphere and inland waters is unknown. We hypothesize...

  13. Combinatorial Control of mRNA Fates by RNA-Binding Proteins and Non-Coding RNAs

    Directory of Open Access Journals (Sweden)

    Valentina Iadevaia

    2015-09-01

    Full Text Available Post-transcriptional control of gene expression is mediated by RNA-binding proteins (RBPs and small non-coding RNAs (e.g., microRNAs that bind to distinct elements in their mRNA targets. Here, we review recent examples describing the synergistic and/or antagonistic effects mediated by RBPs and miRNAs to determine the localisation, stability and translation of mRNAs in mammalian cells. From these studies, it is becoming increasingly apparent that dynamic rearrangements of RNA-protein complexes could have profound implications in human cancer, in synaptic plasticity, and in cellular differentiation.

  14. Identification of residues of the Caenorhabditis elegans LIN-1 ETS domain that are necessary for DNA binding and regulation of vulval cell fates.

    Science.gov (United States)

    Miley, Ginger R; Fantz, Douglas; Glossip, Danielle; Lu, Xiaowei; Saito, R Mako; Palmer, Robert E; Inoue, Takao; Van Den Heuvel, Sander; Sternberg, Paul W; Kornfeld, Kerry

    2004-08-01

    LIN-1 is an ETS domain protein. A receptor tyrosine kinase/Ras/mitogen-activated protein kinase signaling pathway regulates LIN-1 in the P6.p cell to induce the primary vulval cell fate during Caenorhabditis elegans development. We identified 23 lin-1 loss-of-function mutations by conducting several genetic screens. We characterized the molecular lesions in these lin-1 alleles and in several previously identified lin-1 alleles. Nine missense mutations and 10 nonsense mutations were identified. All of these lin-1 missense mutations affect highly conserved residues in the ETS domain. These missense mutations can be arranged in an allelic series; the strongest mutations eliminate most or all lin-1 functions, and the weakest mutation partially reduces lin-1 function. An electrophoretic mobility shift assay was used to demonstrate that purified LIN-1 protein has sequence-specific DNA-binding activity that required the core sequence GGAA. LIN-1 mutant proteins containing the missense substitutions had dramatically reduced DNA binding. These experiments identify eight highly conserved residues of the ETS domain that are necessary for DNA binding. The identification of multiple mutations that reduce the function of lin-1 as an inhibitor of the primary vulval cell fate and also reduce DNA binding suggest that DNA binding is essential for LIN-1 function in an animal.

  15. 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.

  16. Shape-dependent control of cell growth, differentiation, and apoptosis: switching between attractors in cell regulatory networks

    Science.gov (United States)

    Huang, S.; Ingber, D. E.

    2000-01-01

    Development of characteristic tissue patterns requires that individual cells be switched locally between different phenotypes or "fates;" while one cell may proliferate, its neighbors may differentiate or die. Recent studies have revealed that local switching between these different gene programs is controlled through interplay between soluble growth factors, insoluble extracellular matrix molecules, and mechanical forces which produce cell shape distortion. Although the precise molecular basis remains unknown, shape-dependent control of cell growth and function appears to be mediated by tension-dependent changes in the actin cytoskeleton. However, the question remains: how can a generalized physical stimulus, such as cell distortion, activate the same set of genes and signaling proteins that are triggered by molecules which bind to specific cell surface receptors. In this article, we use computer simulations based on dynamic Boolean networks to show that the different cell fates that a particular cell can exhibit may represent a preprogrammed set of common end programs or "attractors" which self-organize within the cell's regulatory networks. In this type of dynamic network model of information processing, generalized stimuli (e.g., mechanical forces) and specific molecular cues elicit signals which follow different trajectories, but eventually converge onto one of a small set of common end programs (growth, quiescence, differentiation, apoptosis, etc.). In other words, if cells use this type of information processing system, then control of cell function would involve selection of preexisting (latent) behavioral modes of the cell, rather than instruction by specific binding molecules. Importantly, the results of the computer simulation closely mimic experimental data obtained with living endothelial cells. The major implication of this finding is that current methods used for analysis of cell function that rely on characterization of linear signaling pathways or

  17. Fate and transport processes controlling the migration of hazardous and radioactive materials from the Area 5 Radioactive Waste Management Site (RWMS)

    Energy Technology Data Exchange (ETDEWEB)

    Estrella, R.

    1994-10-01

    Desert vadose zones have been considered as suitable environments for the safe and long-term isolation of hazardous wastes. Low precipitation, high evapotranspiration and thick unsaturated alluvial deposits commonly found in deserts make them attractive as waste disposal sites. The fate and transport of any contaminant in the subsurface is ultimately determined by the operating retention and transformation processes in the system and the end result of the interactions among them. Retention (sorption) and transformation are the two major processes that affect the amount of a contaminant present and available for transport. Retention processes do not affect the total amount of a contaminant in the soil system, but rather decrease or eliminate the amount available for transport at a given point in time. Sorption reactions retard the contaminant migration. Permanent binding of solute by the sorbent is also possible. These processes and their interactions are controlled by the nature of the hazardous waste, the properties of the porous media and the geochemical and environmental conditions (temperature, moisture and vegetation). The present study summarizes the available data and investigates the fate and transport processes that govern the migration of contaminants from the Radioactive Waste Management Site (RWMS) in Area 5 of the Nevada Test Site (NTS). While the site is currently used only for low-level radioactive waste disposal, past practices have included burial of material now considered hazardous. Fundamentals of chemical and biological transformation processes are discussed subsequently, followed by a discussion of relevant results.

  18. JACKDAW controls epidermal patterning in the Arabidopsis root meristem through a non-cell-autonomous mechanism.

    Science.gov (United States)

    Hassan, Hala; Scheres, Ben; Blilou, Ikram

    2010-05-01

    In Arabidopsis, specification of the hair and non-hair epidermal cell types is position dependent, in that hair cells arise over clefts in the underlying cortical cell layer. Epidermal patterning is determined by a network of transcriptional regulators that respond to an as yet unknown cue from underlying tissues. Previously, we showed that JACKDAW (JKD), a zinc finger protein, localizes in the quiescent centre and the ground tissue, and regulates tissue boundaries and asymmetric cell division by delimiting SHORT-ROOT movement. Here, we provide evidence that JKD controls position-dependent signals that regulate epidermal-cell-type patterning. JKD is required for appropriately patterned expression of the epidermal cell fate regulators GLABRA2, CAPRICE and WEREWOLF. Genetic interaction studies indicate that JKD operates upstream of the epidermal patterning network in a SCRAMBLED (SCM)-dependent fashion after embryogenesis, but acts independent of SCM in embryogenesis. Tissue-specific induction experiments indicate non-cell-autonomous action of JKD from the underlying cortex cell layer to specify epidermal cell fate. Our findings are consistent with a model where JKD induces a signal in every cortex cell that is more abundant in the hair cell position owing to the larger surface contact of cells located over a cleft.

  19. Level of reactive oxygen species induced by p21Waf1/CIP1 is critical for the determination of cell fate.

    Science.gov (United States)

    Inoue, Takafumi; Kato, Kiyoko; Kato, Hidenori; Asanoma, Kazuo; Kuboyama, Ayumi; Ueoka, Yousuke; Yamaguchi, Shin-ichiro; Ohgami, Tatsuhiro; Wake, Norio

    2009-07-01

    p21(WAF(1)/)(CIP(1)) is a well-known cell cycle regulatory protein which is overexpressed in several cancer cell lines, and known to determine cell fate. We generated three recombinant adenovirus vectors that expressed either the full-length p21 (Ad-p21F), a p21 mutant with a deletion of the C-terminal proliferative cell nuclear antigen (PCNA) binding domain (Ad-p21N), or a p21 mutant with a deletion of the N-terminal cyclin-dependent kinase binding domain (Ad-p21C). We transfected these vectors into five cancer cell lines. Premature senescence was induced in all of the lines only following transfection with Ad-p21N and Ad-p21F. In addition, apoptosis was also induced in LoVo and HCT116 cells that harbored wild-type p53 and the reactive oxygen species (ROS) level was higher than in senescent cells. Finally, the induction of apoptosis was inhibited by using siRNA to downregulate p53. This observation implies that there is a feedback signaling loop involving p21/ROS/p53 in apoptotic responses. It appears to be, at least in part, driven by high levels of p21 protein. Next, we investigated the cell death effect of endogenous p21 protein on cell fate using sodium butyrate (NaB). Treatment with 1 mM NaB or 2 to 5 mM NaB induced senescence or apoptosis, respectively. The level of intracellular ROS in 5 mM NaB treated cells was 2-fold higher, compared with that in 1 mM NaB treated cells. We also demonstrated that DNA damage response signals including ataxia telangiectasia mutated, gammaH2AX, and p38 MAPK were involved in NaB-induced cell death. The magnitude of intracellular ROS levels in response to p21 elicited either senescence or apoptosis in the cancer cell lines.

  20. prx-1 functions cooperatively with another paired-related homeobox gene, prx-2, to maintain cell fates within the craniofacial mesenchyme.

    Science.gov (United States)

    Lu, M F; Cheng, H T; Kern, M J; Potter, S S; Tran, B; Diekwisch, T G; Martin, J F

    1999-02-01

    The paired-related homeobox gene, prx-1, is expressed in the postmigratory cranial mesenchyme of all facial prominences and is required for the formation of proximal first arch derivatives. We introduced lacZ into the prx-1 locus to study the developmental fate of cells destined to express prx-1 in the prx-1 mutant background. lacZ was normally expressed in prx-1(neo); prx-1(lacZ )mutant craniofacial mesenchyme up until 11.5 d.p.c. At later time points, lacZ expression was lost from structures that are defective in the prx-1(neo) mutant mice. A related gene, prx-2, demonstrated overlapping expression with prx-1. To test the idea that prx-1 and prx-2 perform redundant functions, we generated prx-1(neo;)prx-2 compound mutant mice. Double mutant mice had novel phenotypes in which the rostral aspect of the mandible was defective, the mandibular incisor arrested as a single, bud-stage tooth germ and Meckel's cartilage was absent. Expression of two markers for tooth development, pax9 and patched, were downregulated. Using a transgene that marks a subset of prx-1-expressing cells in the craniofacial mesenchyme, we showed that cells within the hyoid arch take on the properties of the first branchial arch. These data suggest that prx-1 and prx-2 coordinately regulate gene expression in cells that contribute to the distal aspects of the mandibular arch mesenchyme and that prx-1 and prx-2 play a role in the maintenance of cell fate within the craniofacial mesenchyme.

  1. Hoxb1b controls oriented cell division, cell shape and microtubule dynamics in neural tube morphogenesis.

    Science.gov (United States)

    Zigman, Mihaela; Laumann-Lipp, Nico; Titus, Tom; Postlethwait, John; Moens, Cecilia B

    2014-02-01

    Hox genes are classically ascribed to function in patterning the anterior-posterior axis of bilaterian animals; however, their role in directing molecular mechanisms underlying morphogenesis at the cellular level remains largely unstudied. We unveil a non-classical role for the zebrafish hoxb1b gene, which shares ancestral functions with mammalian Hoxa1, in controlling progenitor cell shape and oriented cell division during zebrafish anterior hindbrain neural tube morphogenesis. This is likely distinct from its role in cell fate acquisition and segment boundary formation. We show that, without affecting major components of apico-basal or planar cell polarity, Hoxb1b regulates mitotic spindle rotation during the oriented neural keel symmetric mitoses that are required for normal neural tube lumen formation in the zebrafish. This function correlates with a non-cell-autonomous requirement for Hoxb1b in regulating microtubule plus-end dynamics in progenitor cells in interphase. We propose that Hox genes can influence global tissue morphogenesis by control of microtubule dynamics in individual cells in vivo.

  2. Graded hedgehog and fibroblast growth factor signaling independently regulate pituitary cell fates and help establish the pars distalis and pars intermedia of the zebrafish adenohypophysis.

    Science.gov (United States)

    Guner, Burcu; Ozacar, A Tuba; Thomas, Jeanne E; Karlstrom, Rolf O

    2008-09-01

    The vertebrate adenohypophysis forms as a placode at the anterior margin of the neural plate, requiring both hedgehog (Hh) and fibroblast growth factor (Fgf) mediated cell-cell signaling for induction and survival of endocrine cell types. Using small molecule inhibitors to modulate signaling levels during zebrafish development we show that graded Hh and Fgf signaling independently help establish the two subdomains of the adenohypophysis, the anteriorly located pars distalis (PD) and the posterior pars intermedia (PI). High levels of Hh signaling are required for formation of the PD and differentiation of anterior endocrine cell types, whereas lower levels of Hh signaling are required for formation of the PI and differentiation of posterior endocrine cell types. In contrast, high Fgf signaling levels are required for formation of the PI and posterior endocrine cell differentiation, whereas anterior regions require lower levels of Fgf signaling. Based on live observations and marker analyses, we show that the PD forms first at the midline closest to the central nervous system source of Sonic hedgehog. In contrast the PI appears to form from more lateral/posterior cells close to a central nervous system source of Fgf3. Together our data show that graded Hh and Fgf signaling independently direct induction of the PD and PI and help establish endocrine cell fates along the anterior/posterior axis of the zebrafish adenohypophysis. These data suggest that there are distinct origins and signaling requirements for the PD and PI.

  3. New insights into the epigenetic control of satellite cells

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Epigenetics finely tunes gene expression at a functionallevel without modifying the DNA sequence, therebycontributing to the complexity of genomic regulation.Satellite cells (SCs) are adult muscle stem cells thatare important for skeletal post-natal muscle growth,homeostasis and repair. The understanding of theepigenome of SCs at different stages and of themultiple layers of the post-transcriptional regulationof gene expression is constantly expanding. Dynamicinteractions between different epigenetic mechanismsregulate the appropriate timing of muscle-specific geneexpression and influence the lineage fate of SCs. Inthis review, we report and discuss the recent literatureabout the epigenetic control of SCs during the myogenicprocess from activation to proliferation and from theircommitment to a muscle cell fate to their differentiationand fusion to myotubes. We describe how the coordinatedactivities of the histone methyltransferasefamilies Polycomb group (PcG), which represses theexpression of developmentally regulated genes, andTrithorax group, which antagonizes the repressive activityof the PcG, regulate myogenesis by restricting geneexpression in a time-dependent manner during eachstep of the process. We discuss how histone acetylationand deacetylation occurs in specific loci throughoutSC differentiation to enable the time-dependent transcriptionof specific genes. Moreover, we describe themultiple roles of microRNA, an additional epigeneticmechanism, in regulating gene expression in SCs, byrepressing or enhancing gene transcription or translationduring each step of myogenesis. The importance ofthese epigenetic pathways in modulating SC activationand differentiation renders them as promising targetsfor disease interventions. Understanding the mostrecent findings regarding the epigenetic mechanismsthat regulate SC behavior is useful from the perspectiveof pharmacological manipulation for improving muscleregeneration and for promoting muscle homeostasisunder

  4. Antagonistic function of Lmd and Zfh1 fine tunes cell fate decisions in the Twi and Tin positive mesoderm of Drosophila melanogaster.

    Science.gov (United States)

    Sellin, Julia; Drechsler, Maik; Nguyen, Hanh T; Paululat, Achim

    2009-02-15

    In this study we show that cell fate decisions in the dorsal and lateral mesoderm of Drosophila melanogaster depend on the antagonistic action of the Gli-like transcription factor Lame duck (Lmd) and the zinc finger homeodomain factor Zfh1. Lmd expression leads to the reduction of Zfh1 positive cell types, thereby restricting the number of Odd-skipped (Odd) positive and Tinman (Tin) positive pericardial cells in the dorsal mesoderm. In more lateral regions, ectopic activation of Zfh1 or loss of Lmd leads to an excess of adult muscle precursor (AMP) like cells. We also observed that Lmd is co-expressed with Tin in the early dorsal mesoderm and leads to a reduction of Tin expression in cells destined to become dorsal fusion competent myoblasts (FCMs). In the absence of Lmd function, these cells remain Tin positive and develop as Tin positive pericardial cells although they do not express Zfh1. We show further that Tin repression and pericardial restriction in the dorsal mesoderm facilitated by Lmd is instructed by a late Decapentaplegic (Dpp) signal that is abolished in embryos carrying the disk region mutation dpp(d6).

  5. Control of mesenchymal stem cell phenotype and differentiation depending on cell adhesion mechanism

    Directory of Open Access Journals (Sweden)

    J Kang

    2014-11-01

    Full Text Available Control of cell-matrix adhesion has become an important issue in the regulation of stem cell function. In this study, a maltose-binding protein (MBP-linked basic fibroblast growth factor (FGF2-immobilised polystyrene surface (PS-MBP-FGF2 was applied as an artificial matrix to regulate integrin-mediated signalling. We sought to characterise human mesenchymal-stem cell (hMSC behaviour in response to two different mechanisms of cell adhesion; (i FGF2-heparan sulphate proteoglycan (HSPG-mediated adhesion vs. (ii fibronectin (FN-integrin-mediated adhesion. Heparin inhibited hMSC adhesion to PS-MBP-FGF2 but not to FN-coated surface. The phosphorylation of focal adhesion kinase, cytoskeletal re-organisation, and cell proliferation were restricted in hMSCs adhering to PS-MBP-FGF2 compared to FN-coated surface. Expression of MSC markers, such as CD105, CD90 and CD166, decreased in hMSCs expanded on PS-MBP-FGF2 compared to expression in cells expanded on FN-coated surface. hMSCs that were expanded on FN-coated surface differentiated into osteogenic and adipogenic cells more readily than those that were expanded on PS-MBP-FGF2. Furthermore, we characterised the N-linked glycan structures of hMSCs depending on the cell adhesion mechanism using mass spectrometry (MS-based quantitative techniques. MS analysis revealed that 2,3-sialylated glycans, a potential marker of stem cell function, were more abundant on hMSCs expanded on FN-coated surface than on those expanded on PS-MBP-FGF2. Thus, the differentiation potential of hMSCs is controlled by the type of adhesion substrate that might provide an idea for the design of biomaterials to control stem cell fate. Elucidation of the glycan structure on the cell membrane may help characterise hMSC function.

  6. Control of mesenchymal stem cell phenotype and differentiation depending on cell adhesion mechanism.

    Science.gov (United States)

    Kang, J; Park, H M; Kim, Y W; Kim, Y H; Varghese, S; Seok, H K; Kim, Y G; Kim, S H

    2014-11-25

    Control of cell-matrix adhesion has become an important issue in the regulation of stem cell function. In this study, a maltose-binding protein (MBP)-linked basic fibroblast growth factor (FGF2)-immobilised polystyrene surface (PS-MBP-FGF2) was applied as an artificial matrix to regulate integrin-mediated signalling. We sought to characterise human mesenchymal-stem cell (hMSC) behaviour in response to two different mechanisms of cell adhesion; (i) FGF2-heparan sulphate proteoglycan (HSPG)-mediated adhesion vs. (ii) fibronectin (FN)-integrin-mediated adhesion. Heparin inhibited hMSC adhesion to PS-MBP-FGF2 but not to FN-coated surface. The phosphorylation of focal adhesion kinase, cytoskeletal re-organisation, and cell proliferation were restricted in hMSCs adhering to PS-MBP-FGF2 compared to FN-coated surface. Expression of MSC markers, such as CD105, CD90 and CD166, decreased in hMSCs expanded on PS-MBP-FGF2 compared to expression in cells expanded on FN-coated surface. hMSCs that were expanded on FN-coated surface differentiated into osteogenic and adipogenic cells more readily than those that were expanded on PS-MBP-FGF2. Furthermore, we characterised the N-linked glycan structures of hMSCs depending on the cell adhesion mechanism using mass spectrometry (MS)-based quantitative techniques. MS analysis revealed that 2,3-sialylated glycans, a potential marker of stem cell function, were more abundant on hMSCs expanded on FN-coated surface than on those expanded on PS-MBP-FGF2. Thus, the differentiation potential of hMSCs is controlled by the type of adhesion substrate that might provide an idea for the design of biomaterials to control stem cell fate. Elucidation of the glycan structure on the cell membrane may help characterise hMSC function.

  7. The effects of various control and water treatment processes on the membrane integrity and toxin fate of cyanobacteria.

    Science.gov (United States)

    Fan, Jiajia; Hobson, Peter; Ho, Lionel; Daly, Robert; Brookes, Justin

    2014-01-15

    Cyanobacterial blooms are one of the main contaminants that can degrade drinking water quality with the associated taste, odour and toxic compounds. Although a wide range of techniques have shown promise for cyanobacterial bloom control and cyanobacterial cell/metabolite removal in reservoirs and water treatment plants (WTPs), these treatments may have negative consequences through release of intracellular metabolites into the surrounding water. This study assessed the impact of copper sulphate (CuSO4), chlorine, potassium permanganate (KMnO4), hydrogen peroxide (H2O2) and ozone on Microcystis aeruginosa culture and the toxins it produced. All of these agents induced the loss of cyanobacterial membrane integrity. However, no associated increase in dissolved toxins was detected during chlorine and H2O2 treatments which may be due to faster toxin oxidation rates than release rates. KMnO4 doses of 1 and 3mgL(-1) degraded dissolved toxins while having no impact on cyanobacterial membrane integrity. In contrast, ozone induced a significant increase in extracellular toxins but it was unable to degrade these toxins to the same degree as the other oxidants which may due to the lack of residual. All chemicals, except CuSO4, were able to reduce cyanotoxins and chlorine was the most effective with a rate up to 2161M(-1)s(-1).

  8. A regulatory framework for shoot stem cell control integrating metabolic, transcriptional, and phytohormone signals.

    Science.gov (United States)

    Schuster, Christoph; Gaillochet, Christophe; Medzihradszky, Anna; Busch, Wolfgang; Daum, Gabor; Krebs, Melanie; Kehle, Andreas; Lohmann, Jan U

    2014-02-24

    Plants continuously maintain pluripotent stem cells embedded in specialized tissues called meristems, which drive long-term growth and organogenesis. Stem cell fate in the shoot apical meristem (SAM) is controlled by the homeodomain transcription factor WUSCHEL (WUS) expressed in the niche adjacent to the stem cells. Here, we demonstrate that the bHLH transcription factor HECATE1 (HEC1) is a target of WUS and that it contributes to SAM function by promoting stem cell proliferation, while antagonizing niche cell activity. HEC1 represses the stem cell regulators WUS and CLAVATA3 (CLV3) and, like WUS, controls genes with functions in metabolism and hormone signaling. Among the targets shared by HEC1 and WUS are phytohormone response regulators, which we show to act as mobile signals in a universal feedback system. Thus, our work sheds light on the mechanisms guiding meristem function and suggests that the underlying regulatory system is far more complex than previously anticipated.

  9. Direct and indirect influences of fate control belief, gambling expectancy bias, and self-efficacy on problem gambling and negative mood among Chinese college students: a multiple mediation analysis.

    Science.gov (United States)

    Tang, Catherine So-Kum; Wu, Anise M S

    2010-12-01

    A multiple mediation model was proposed to integrate core concepts of the social axioms framework and the social cognitive theory in order to understand gambling behavior. It was hypothesized that the influence of general fate control belief on problem gambling and negative mood would be mediated by gambling-specific beliefs. Data from 773 Chinese college recreational gamblers were collected. The bootstrapping procedure was used to test the multiple mediation hypotheses. Significant indirect effects of fate control belief on problem gambling and negative mood through two gambling-specific mediators were found. Gambling expectancy bias was a more salient mediator than gambling self-efficacy. Fate control belief was also found to have a significant direct effect on negative mood. In general, a high level of general fate control belief was related to greater gambling expectancy bias and lower self-efficacy in resisting gambling, which were in turn related to problem gambling and negative mood. Limitations and implications of the study were discussed.

  10. 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

  11. Heat reduces nitric oxide production required for auxin-mediated gene expression and fate determination in tree tobacco guard cell protoplasts.

    Science.gov (United States)

    Beard, Robert A; Anderson, David J; Bufford, Jennifer L; Tallman, Gary

    2012-08-01

    Tree tobacco (Nicotiana glauca) is an equatorial perennial with a high basal thermotolerance. Cultured tree tobacco guard cell protoplasts (GCPs) are useful for studying the effects of heat stress on fate-determining hormonal signaling. At lower temperatures (32°C or less), exogenous auxin (1-naphthalene acetic acid) and cytokinin (6-benzylaminopurine) cause GCPs to expand 20- to 30-fold, regenerate cell walls, dedifferentiate, reenter the cell cycle, and divide. At higher temperatures (34°C or greater), GCPs expand only 5- to 6-fold; they do not regenerate walls, dedifferentiate, reenter the cell cycle, or divide. Heat (38°C) suppresses activation of the BA auxin-responsive transgene promoter in tree tobacco GCPs, suggesting that inhibition of cell expansion and cell cycle reentry at high temperatures is due to suppressed auxin signaling. Nitric oxide (NO) has been implicated in auxin signaling in other plant systems. Here, we show that heat inhibits NO accumulation by GCPs and that L-N(G)-monomethyl arginine, an inhibitor of NO production in animals and plants, mimics the effects of heat by limiting cell expansion and preventing cell wall regeneration; inhibiting cell cycle reentry, dedifferentiation, and cell division; and suppressing activation of the BA auxin-responsive promoter. We also show that heat and L-N(G)-monomethyl arginine reduce the mitotic indices of primary root meristems and inhibit lateral root elongation similarly. These data link reduced NO levels to suppressed auxin signaling in heat-stressed cells and seedlings of thermotolerant plants and suggest that even plants that have evolved to withstand sustained high temperatures may still be negatively impacted by heat stress.

  12. Expression of FATE/BJ-HCC-2 Promotes Cell Proliferation and Tumorigenesis%FATE/BJ-HCC-2基因表达促进细胞增殖及肿瘤形成

    Institute of Scientific and Technical Information of China (English)

    闫萌; 王巍; 杨小昂; 张毓; 尹艳慧; 陈慰峰

    2008-01-01

    FATE/BJ-HCC-2是本实验室鉴定的一个新的肿瘤.睾丸抗原基因,定位于Xq28染色体.为探讨FATE/BJ-HCC-2对细胞生物学行为的影响及裸鼠体内肿瘤形成能力的改变,分别采用脂质体转染真核表达栽体及逆转录病毒感染两种方式,获得了FATE/BJ-HCC-2表达的Bel-7402单克隆细胞株及NIH-3T3细胞克隆,并通过RT-PCR和Western印迹在基因和蛋白水平鉴定了FATE/BJ-HCC-2表达情况.通过3 H-TdR参入法,检测细胞的增殖能力;通过稀释铺板集落形成率测定和软琼脂集落形成实验,检测细胞的集落形成能力;通过裸鼠体内细胞注射成瘤,检测细胞成瘤性和肿瘤生长速度.结果表明,FATE/BJ-HCC-2基因表达能明显提高细胞体外增殖、克隆形成能力和成瘤性.提示其对肿瘤的发生发展起到促进作用.

  13. Regulation of cell fate by lymphotoxin (LT) receptor signalling: Functional differences and similarities of the LT system to other TNF superfamily (TNFSF) members.

    Science.gov (United States)

    Albarbar, Balid; Dunnill, Christopher; Georgopoulos, Nikolaos T

    2015-12-01

    The role of TNFR family members in regulating cell fate both in the immune system and in non-lymphoid tissues has been under extensive research for decades. Moreover, the ability of several family members (death receptors) to induce death (mainly via apoptosis) represents a promising target for cancer therapy. Many studies have focused mostly on death receptors such as TNFRI, Fas and TRAIL-R due to their strong pro-apoptotic potential. Yet, cell death can be triggered via non-classical death receptors, and the lymphotoxin (LT) system represents a very good example of such a TNFR subfamily. Here we provide a comprehensive review of intracellular signalling pathways and cellular responses to LT-specific signalling, and compare for the first time the LT system to other TNFRs, such as CD40. Our aim is to highlight that non-classical TNFR-TNFL dyads such as the LT system demonstrate more complex, cell-type and context-specific capabilities. Understanding these complexities will permit a better understanding of the biological mechanisms via which non-death domain-containing TNFRs induce cell death, but may also allow the design of better therapeutic strategies.

  14. Efficient endoderm induction from human pluripotent stem cells by logically directing signals controlling lineage bifurcations.

    Science.gov (United States)

    Loh, Kyle M; Ang, Lay Teng; Zhang, Jingyao; Kumar, Vibhor; Ang, Jasmin; Auyeong, Jun Qiang; Lee, Kian Leong; Choo, Siew Hua; Lim, Christina Y Y; Nichane, Massimo; Tan, Junru; Noghabi, Monireh Soroush; Azzola, Lisa; Ng, Elizabeth S; Durruthy-Durruthy, Jens; Sebastiano, Vittorio; Poellinger, Lorenz; Elefanty, Andrew G; Stanley, Edouard G; Chen, Qingfeng; Prabhakar, Shyam; Weissman, Irving L; Lim, Bing

    2014-02-01

    Human pluripotent stem cell (hPSC) differentiation typically yields heterogeneous populations. Knowledge of signals controlling embryonic lineage bifurcations could efficiently yield desired cell types through exclusion of alternate fates. Therefore, we revisited signals driving induction and anterior-posterior patterning of definitive endoderm to generate a coherent roadmap for endoderm differentiation. With striking temporal dynamics, BMP and Wnt initially specified anterior primitive streak (progenitor to endoderm), yet, 24 hr later, suppressed endoderm and induced mesoderm. At lineage bifurcations, cross-repressive signals separated mutually exclusive fates; TGF-β and BMP/MAPK respectively induced pancreas versus liver from endoderm by suppressing the alternate lineage. We systematically blockaded alternate fates throughout multiple consecutive bifurcations, thereby efficiently differentiating multiple hPSC lines exclusively into endoderm and its derivatives. Comprehensive transcriptional and chromatin mapping of highly pure endodermal populations revealed that endodermal enhancers existed in a surprising diversity of "pre-enhancer" states before activation, reflecting the establishment of a permissive chromatin landscape as a prelude to differentiation.

  15. Impact of Spent Mushroom Substrates on the Fate of Pesticides in Soil, and Their Use for Preventing and/or Controlling Soil and Water Contamination: A Review

    Directory of Open Access Journals (Sweden)

    Jesús M. Marín-Benito

    2016-08-01

    Full Text Available Intensive crop production involves a high consumption of pesticides. This is a cause of major environmental concern because the presence of pesticides in water is becoming increasingly common. Physicochemical methods based on soil modification with organic residues have been developed to enhance the immobilization and/or degradation of pesticides in agricultural soils, which may control both the diffuse and the point pollution of soils and waters. This review summarizes the influence of spent mushroom substrate (SMS on the environmental fate of pesticides when both are simultaneously applied in agriculture. The processes of adsorption, leaching and dissipation of these compounds in SMS-amended soils were evaluated at laboratory and field scale. Relationships were established between the experimental parameters obtained and the properties of the soils, the SMS, and the pesticides in order to determine the effect that the application of SMS in agricultural soils has on the environmental impact of pesticides. Accordingly, this review highlights the use of SMS as a strategy for the prevention and/or control of soil and water contamination by pesticides to strike a balance between agricultural development and the use of these compounds.

  16. Vascular Endothelial Growth Factor Receptor 3 Controls Neural Stem Cell Activation in Mice and Humans

    Directory of Open Access Journals (Sweden)

    Jinah Han

    2015-02-01

    Full Text Available Neural stem cells (NSCs continuously produce new neurons within the adult mammalian hippocampus. NSCs are typically quiescent but activated to self-renew or differentiate into neural progenitor cells. The molecular mechanisms of NSC activation remain poorly understood. Here, we show that adult hippocampal NSCs express vascular endothelial growth factor receptor (VEGFR 3 and its ligand VEGF-C, which activates quiescent NSCs to enter the cell cycle and generate progenitor cells. Hippocampal NSC activation and neurogenesis are impaired by conditional deletion of Vegfr3 in NSCs. Functionally, this is associated with compromised NSC activation in response to VEGF-C and physical activity. In NSCs derived from human embryonic stem cells (hESCs, VEGF-C/VEGFR3 mediates intracellular activation of AKT and ERK pathways that control cell fate and proliferation. These findings identify VEGF-C/VEGFR3 signaling as a specific regulator of NSC activation and neurogenesis in mammals.

  17. Direct cell fate conversion of human somatic stem cells into cone and rod photoreceptor-like cells by inhibition of microRNA-203

    OpenAIRE

    Choi, Soon Won; Shin, Ji-Hee; Kim, Jae-Jun; Shin, Tae-Hoon; Seo, Yoojin; Kim, Hyung-Sik; Kang, Kyung-Sun

    2016-01-01

    Stem cell-based photoreceptor differentiation strategies have been the recent focus of therapies for retinal degenerative diseases. Previous studies utilized embryonic stem (ES) cells and neural retina differentiation cocktails, including DKK1 and Noggin. Here, we show a novel microRNA-mediated strategy of retina differentiation from somatic stem cells, which are potential allogeneic cell sources. Human amniotic epithelial stem cells (AESCs) and umbilical cord blood-derived mesenchymal stem c...

  18. Chemo-mechanical control of neural stem cell differentiation

    Science.gov (United States)

    Geishecker, Emily R.

    Cellular processes such as adhesion, proliferation, and differentiation are controlled in part by cell interactions with the microenvironment. Cells can sense and respond to a variety of stimuli, including soluble and insoluble factors (such as proteins and small molecules) and externally applied mechanical stresses. Mechanical properties of the environment, such as substrate stiffness, have also been suggested to play an important role in cell processes. The roles of both biochemical and mechanical signaling in fate modification of stem cells have been explored independently. However, very few studies have been performed to study well-controlled chemo-mechanotransduction. The objective of this work is to design, synthesize, and characterize a chemo-mechanical substrate to encourage neuronal differentiation of C17.2 neural stem cells. In Chapter 2, Polyacrylamide (PA) gels of varying stiffnesses are functionalized with differing amounts of whole collagen to investigate the role of protein concentration in combination with substrate stiffness. As expected, neurons on the softest substrate were more in number and neuronal morphology than those on stiffer substrates. Neurons appeared locally aligned with an expansive network of neurites. Additional experiments would allow for statistical analysis to determine if and how collagen density impacts C17.2 differentiation in combination with substrate stiffness. Due to difficulties associated with whole protein approaches, a similar platform was developed using mixed adhesive peptides, derived from fibronectin and laminin, and is presented in Chapter 3. The matrix elasticity and peptide concentration can be individually modulated to systematically probe the effects of chemo-mechanical signaling on differentiation of C17.2 cells. Polyacrylamide gel stiffness was confirmed using rheological techniques and found to support values published by Yeung et al. [1]. Cellular growth and differentiation were assessed by cell counts

  19. Adenovirus E4orf6 targets pp32/LANP to control the fate of ARE-containing mRNAs by perturbing the CRM1-dependent mechanism.

    Science.gov (United States)

    Higashino, Fumihiro; Aoyagi, Mariko; Takahashi, Akiko; Ishino, Masaho; Taoka, Masato; Isobe, Toshiaki; Kobayashi, Masanobu; Totsuka, Yasunori; Kohgo, Takao; Shindoh, Masanobu

    2005-07-04

    E4orf6 plays an important role in the transportation of cellular and viral mRNAs and is known as an oncogene product of adenovirus. Here, we show that E4orf6 interacts with pp32/leucine-rich acidic nuclear protein (LANP). E4orf6 exports pp32/LANP from the nucleus to the cytoplasm with its binding partner, HuR, which binds to an AU-rich element (ARE) present within many protooncogene and cytokine mRNAs. We found that ARE-mRNAs, such as c-fos, c-myc, and cyclooxygenase-2, were also exported to and stabilized in the cytoplasm of E4orf6-expressing cells. The oncodomain of E4orf6 was necessary for both binding to pp32/LANP and effect for ARE-mRNA. C-fos mRNA was exported together with E4orf6, E1B-55kD, pp32/LANP, and HuR proteins. Moreover, inhibition of the CRM1-dependent export pathway failed to block the export of ARE-mRNAs mediated by E4orf6. Thus, E4orf6 interacts with pp32/LANP to modulate the fate of ARE-mRNAs by altering the CRM1-dependent export pathway.

  20. Cellular and molecular markers in monitoring the fate of lymphoid cell culture from Penaeus monodon Fabricius (1798).

    Science.gov (United States)

    Puthumana, Jayesh; Jose, Seena; Philip, Rosamma; Singh, I S Bright

    2015-12-01

    Lymphoid cell culture from penaeid shrimps has gained much acceptance as an in vitro platform to facilitate research on the development of prophylaxis, and therapeutic strategies against viruses and for cell line development. However, lymphoid cells can be used as platform for in vitro research, only if they are in metabolically and mitotically active state in vitro with unaltered cell surface receptors. Through this study, we addressed the response of lymphoid cells to a new microenvironment at cellular and molecular levels; including the study of mitotic events, DNA synthesis, expression profile of cell cycle genes, cytoskeleton organization, metabolic activity and viral susceptibility. The S-phase entry and synthesis of new DNA was recorded by immunoflourescent technique. Cdc2, CycA, CycB, EF-1α and BUB3 genes involved in cell cycle were studied in both the cells and tissue, of which EF-1α showed an elevated expression in cells in vitro (∼ 19.7%). Cytoskeleton network of the cell was examined by studying the organization of actin filaments. As the markers for metabolic status, mitochondrial dehydrogenase, protein synthesis and glucose assimilation by the cells were also assessed. Viral susceptibility of the cell was determined using WSSV to confirm the preservation of cellular receptors. This study envisages to strengthen the shrimp cell line research and to bring forth lymphoid cell culture system as a 'model' in vitro system for shrimp and crustaceans altogether.

  1. Dimensionality controls cytoskeleton assembly and metabolism of fibroblast cells in response to rigidity and shape.

    Directory of Open Access Journals (Sweden)

    Mirjam Ochsner

    Full Text Available BACKGROUND: Various physical parameters, including substrate rigidity, size of adhesive islands and micro-and nano-topographies, have been shown to differentially regulate cell fate in two-dimensional (2-D cell cultures. Cells anchored in a three-dimensional (3-D microenvironment show significantly altered phenotypes, from altered cell adhesions, to cell migration and differentiation. Yet, no systematic analysis has been performed that studied how the integrated cellular responses to the physical characteristics of the environment are regulated by dimensionality (2-D versus 3-D. METHODOLOGY/PRINCIPAL FINDINGS: Arrays of 5 or 10 microm deep microwells were fabricated in polydimethylsiloxane (PDMS. The actin cytoskeleton was compared for single primary fibroblasts adhering either to microfabricated adhesive islands (2-D or trapped in microwells (3-D of controlled size, shape, and wall rigidity. On rigid substrates (Young's Modulus = 1 MPa, cytoskeleton assembly within single fibroblast cells occurred in 3-D microwells of circular, rectangular, square, and triangular shapes with 2-D projected surface areas (microwell bottom surface area and total surface areas of adhesion (microwell bottom plus wall surface area that inhibited stress fiber assembly in 2-D. In contrast, cells did not assemble a detectable actin cytoskeleton in soft 3-D microwells (20 kPa, regardless of their shapes, but did so on flat, 2-D substrates. The dependency on environmental dimensionality was also reflected by cell viability and metabolism as probed by mitochondrial activities. Both were upregulated in 3-D cultured cells versus cells on 2-D patterns when surface area of adhesion and rigidity were held constant. CONCLUSION/SIGNIFICANCE: These data indicate that cell shape and rigidity are not orthogonal parameters directing cell fate. The sensory toolbox of cells integrates mechanical (rigidity and topographical (shape and dimensionality information differently when cell

  2. Molecular mechanisms controlling the cell cycle in embryonic stem cells.

    Science.gov (United States)

    Abdelalim, Essam M

    2013-12-01

    Embryonic stem (ES) cells are originated from the inner cell mass of a blastocyst stage embryo. They can proliferate indefinitely, maintain an undifferentiated state (self-renewal), and differentiate into any cell type (pluripotency). ES cells have an unusual cell cycle structure, consists mainly of S phase cells, a short G1 phase and absence of G1/S checkpoint. Cell division and cell cycle progression are controlled by mechanisms ensuring the accurate transmission of genetic information from generation to generation. Therefore, control of cell cycle is a complicated process, involving several signaling pathways. Although great progress has been made on the molecular mechanisms involved in the regulation of ES cell cycle, many regulatory mechanisms remain unknown. This review summarizes the current knowledge about the molecular mechanisms regulating the cell cycle of ES cells and describes the relationship existing between cell cycle progression and the self-renewal.

  3. Outdoor fate and environmental impact of polymer solar cells through leaching and emission to rainwater and soil

    NARCIS (Netherlands)

    Espinosa, Nieves; Zimmermann, Yannick-Serge; Reis Benatto, Dos Gisele A.; Lenz, Markus; Krebs, Frederik C.

    2016-01-01

    The emission of silver and zinc to the aqueous environment (rain, fog, dew) from polymer solar cells installed outdoors is presented. Studies included pristine solar cells and solar cells subjected to mechanical damage under natural weather conditions in Denmark. We find the emission of silver and z

  4. FOXP3+ T Cells Recruited to Sites of Sterile Skeletal Muscle Injury Regulate the Fate of Satellite Cells and Guide Effective Tissue Regeneration.

    Directory of Open Access Journals (Sweden)

    Alessandra Castiglioni

    Full Text Available Muscle injury induces a classical inflammatory response in which cells of the innate immune system rapidly invade the tissue. Macrophages are prominently involved in this response and required for proper healing, as they are known to be important for clearing cellular debris and supporting satellite cell differentiation. Here, we sought to assess the role of the adaptive immune system in muscle regeneration after acute damage. We show that T lymphocytes are transiently recruited into the muscle after damage and appear to exert a pro-myogenic effect on muscle repair. We observed a decrease in the cross-sectional area of regenerating myofibers after injury in Rag2-/- γ-chain-/- mice, as compared to WT controls, suggesting that T cell recruitment promotes muscle regeneration. Skeletal muscle infiltrating T lymphocytes were enriched in CD4+CD25+FOXP3+ cells. Direct exposure of muscle satellite cells to in vitro induced Treg cells effectively enhanced their expansion, and concurrently inhibited their myogenic differentiation. In vivo, the recruitment of Tregs to acutely injured muscle was limited to the time period of satellite expansion, with possibly important implications for situations in which inflammatory conditions persist, such as muscular dystrophies and inflammatory myopathies. We conclude that the adaptive immune system, in particular T regulatory cells, is critically involved in effective skeletal muscle regeneration. Thus, in addition to their well-established role as regulators of the immune/inflammatory response, T regulatory cells also regulate the activity of skeletal muscle precursor cells, and are instrumental for the proper regeneration of this tissue.

  5. FOXP3+ T Cells Recruited to Sites of Sterile Skeletal Muscle Injury Regulate the Fate of Satellite Cells and Guide Effective Tissue Regeneration.

    Science.gov (United States)

    Castiglioni, Alessandra; Corna, Gianfranca; Rigamonti, Elena; Basso, Veronica; Vezzoli, Michela; Monno, Antonella; Almada, Albert E; Mondino, Anna; Wagers, Amy J; Manfredi, Angelo A; Rovere-Querini, Patrizia

    2015-01-01

    Muscle injury induces a classical inflammatory response in which cells of the innate immune system rapidly invade the tissue. Macrophages are prominently involved in this response and required for proper healing, as they are known to be important for clearing cellular debris and supporting satellite cell differentiation. Here, we sought to assess the role of the adaptive immune system in muscle regeneration after acute damage. We show that T lymphocytes are transiently recruited into the muscle after damage and appear to exert a pro-myogenic effect on muscle repair. We observed a decrease in the cross-sectional area of regenerating myofibers after injury in Rag2-/- γ-chain-/- mice, as compared to WT controls, suggesting that T cell recruitment promotes muscle regeneration. Skeletal muscle infiltrating T lymphocytes were enriched in CD4+CD25+FOXP3+ cells. Direct exposure of muscle satellite cells to in vitro induced Treg cells effectively enhanced their expansion, and concurrently inhibited their myogenic differentiation. In vivo, the recruitment of Tregs to acutely injured muscle was limited to the time period of satellite expansion, with possibly important implications for situations in which inflammatory conditions persist, such as muscular dystrophies and inflammatory myopathies. We conclude that the adaptive immune system, in particular T regulatory cells, is critically involved in effective skeletal muscle regeneration. Thus, in addition to their well-established role as regulators of the immune/inflammatory response, T regulatory cells also regulate the activity of skeletal muscle precursor cells, and are instrumental for the proper regeneration of this tissue.

  6. 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......The emission of silver and zinc to the aqueous environment (rain, fog, dew) from polymer solar cells installed outdoors is presented. Studies included pristine solar cells and solar cells subjected to mechanical damage under natural weather conditions in Denmark. We find the emission of silver...

  7. The Fate and Distribution of Autologous Bone Marrow Mesenchymal Stem Cells with Intra-Arterial Infusion in Osteonecrosis of the Femoral Head in Dogs

    Directory of Open Access Journals (Sweden)

    Hongting Jin

    2016-01-01

    Full Text Available This study aimed to investigate if autologous bone marrow mesenchymal stem cells (MSCs could treat osteonecrosis of the femoral head (ONFH and what the fate and distribution of the cells are in dogs. Twelve Beagle dogs were randomly divided into two groups: MSCs group and SHAM operated group. After three weeks, dogs in MSCs group and SHAM operated group were intra-arterially injected with autologous MSCs and 0.9% normal saline, respectively. Eight weeks after treatment, the necrotic volume of the femoral heads was significantly reduced in MSCs group. Moreover, the trabecular bone volume was increased and the empty lacunae rate was decreased in MSCs group. In addition, the BrdU-positive MSCs were unevenly distributed in femoral heads and various vital organs. But no obvious abnormalities were observed. Furthermore, most of BrdU-positive MSCs in necrotic region expressed osteocalcin in MSCs group and a few expressed peroxisome proliferator-activated receptor-γ (PPAR-γ. Taken together, these data indicated that intra-arterially infused MSCs could migrate into the necrotic field of femoral heads and differentiate into osteoblasts, thus improving the necrosis of femoral heads. It suggests that intra-arterial infusion of autologous MSCs might be a feasible and relatively safe method for the treatment of femoral head necrosis.

  8. Prediction of neural differentiation fate of rat mesenchymal stem cells by quantitative morphological analyses using image processing techniques.

    Science.gov (United States)

    Kazemimoghadam, Mahdieh; Janmaleki, Mohsen; Fouani, Mohamad Hassan; Abbasi, Sara

    2015-02-01

    Differentiation of bone marrow mesenchymal stem cells (BMSCs) into neural cells has received significant attention in recent years. However, there is still no practical method to evaluate differentiation process non-invasively and practically. The cellular quality evaluation method is still limited to conventional techniques, which are based on extracting genes or proteins from the cells. These techniques are invasive, costly, time consuming, and should be performed by relevant experts in equipped laboratories. Moreover, they cannot anticipate the future status of cells. Recently, cell morphology has been introduced as a feasible way of monitoring cell behavior because of its relationship with cell proliferation, functions and differentiation. In this study, rat BMSCs were induced to differentiate into neurons. Subsequently, phase contrast images of cells taken at certain intervals were subjected to a series of image processing steps and cell morphology features were calculated. In order to validate the viability of applying image-based approaches for estimating the quality of differentiation process, neural-specific markers were measured experimentally throughout the induction. The strong correlation between quantitative imaging metrics and experimental outcomes revealed the capability of the proposed approach as an auxiliary method of assessing cell behavior during differentiation.

  9. Fuel cell with internal flow control

    Science.gov (United States)

    Haltiner, Jr., Karl J.; Venkiteswaran, Arun [Karnataka, IN

    2012-06-12

    A fuel cell stack is provided with a plurality of fuel cell cassettes where each fuel cell cassette has a fuel cell with an anode and cathode. The fuel cell stack includes an anode supply chimney for supplying fuel to the anode of each fuel cell cassette, an anode return chimney for removing anode exhaust from the anode of each fuel cell cassette, a cathode supply chimney for supplying oxidant to the cathode of each fuel cell cassette, and a cathode return chimney for removing cathode exhaust from the cathode of each fuel cell cassette. A first fuel cell cassette includes a flow control member disposed between the anode supply chimney and the anode return chimney or between the cathode supply chimney and the cathode return chimney such that the flow control member provides a flow restriction different from at least one other fuel cell cassettes.

  10. Direct cell fate conversion of human somatic stem cells into cone and rod photoreceptor-like cells by inhibition of microRNA-203.

    Science.gov (United States)

    Choi, Soon Won; Shin, Ji-Hee; Kim, Jae-Jun; Shin, Tae-Hoon; Seo, Yoojin; Kim, Hyung-Sik; Kang, Kyung-Sun

    2016-07-05

    Stem cell-based photoreceptor differentiation strategies have been the recent focus of therapies for retinal degenerative diseases. Previous studies utilized embryonic stem (ES) cells and neural retina differentiation cocktails, including DKK1 and Noggin. Here, we show a novel microRNA-mediated strategy of retina differentiation from somatic stem cells, which are potential allogeneic cell sources. Human amniotic epithelial stem cells (AESCs) and umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) treated with a retina differentiation cocktail induced gene expressions of retina development-relevant genes. Furthermore, microRNA-203 (miR-203) is abundantly expressed in human AESCs and human UCB-MSCs. This miR-203 is predicted to target multiple retina development-relevant genes, particularly DKK1, CRX, RORβ, NEUROD1, NRL and THRB. The inhibition of miR-203 induced a retina differentiation of AESCs and UCB-MSCs. Moreover, successive treatments of anti-miR-203 led to the expression of both mature photoreceptor (PR) markers, rhodopsin and opsin. In addition, we determined that CRX, NRL and DKK1 are direct targets of miR-203 using a luciferase assay. Thus, the work presented here suggests that somatic stem cells can potentially differentiate into neural retina cell types when treated with anti-miR-203. They may prove to be a source of both PR subtypes for future allogeneic stem cell-based therapies of non-regenerative retina diseases.

  11. p53 as the main traffic controller of the cell signaling network.

    Science.gov (United States)

    Sebastian, Sinto; Azzariti, Amalia; Silvestris, Nicola; Porcelli, Letizia; Russo, Antonio; Paradiso, Angelo

    2010-06-01

    Among different pathological conditions that affect human beings, cancer has received a great deal of attention primarily because it leads to significant morbidity and mortality. This is essentially due to increasing world-wide incidence of this disease and the inability to discover the cause and molecular mechanisms by which normal human cells acquire the characteristics that define cancer cells. Since the discovery of p53 over a quarter of a century ago, it is now recognized that virtually all cell fate pathways of live cells and the decision to die are under the control of p53. Such extensive involvement indicates that p53 protein is acting as a major traffic controller in the cell signaling network. In cancer cells, many cell signaling pathways of normal human cells are rerouted towards immortalization and this is accomplished by the corruption of the main controllers of cell signaling pathways such as p53. This review highlights how p53 signaling activity is altered in cancer cells so that cells acquire the hallmarks of cancer including deregulated infinite self replicative potential.

  12. Expression kinetics of hepatic progenitor markers in cellular models of human liver development recapitulating hepatocyte and biliary cell fate commitment.

    Science.gov (United States)

    Chaudhari, Pooja; Tian, Lipeng; Deshmukh, Abhijeet; Jang, Yoon-Young

    2016-09-01

    Due to the limitations of research using human embryos and the lack of a biological model of human liver development, the roles of the various markers associated with liver stem or progenitor cell potential in humans are largely speculative, and based on studies utilizing animal models and certain patient tissues. Human pluripotent stem cell-based in vitro multistage hepatic differentiation systems may serve as good surrogate models for mimicking normal human liver development, pathogenesis and injury/regeneration studies. Here, we describe the implications of various liver stem or progenitor cell markers and their bipotency (i.e. hepatocytic- and biliary-epithelial cell differentiation), based on the pluripotent stem cell-derived model of human liver development. Future studies using the human cellular model(s) of liver and biliary development will provide more human relevant biological and/or pathological roles of distinct markers expressed in heterogeneous liver stem/progenitor cell populations.

  13. Fate of HERS during Tooth Root Development

    OpenAIRE

    HUANG, XIAOFENG; BRINGAS, PABLO; Slavkin, Harold C.; Chai, Yang

    2009-01-01

    Tooth root development begins after the completion of crown formation in mammals. Previous studies have shown that Hertwig's epithelial root sheath (HERS) plays an important role in root development, but the fate of HERS has remained unknown. In order to investigate the morphological fate and analyze the dynamic movement of HERS cells in vivo, we generated K14-Cre;R26R mice. HERS cells are detectable on the surface of the root throughout root formation and do not disappear. Most of the HERS c...

  14. 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|info:eu-repo/dai/nl/073356328; 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 diffe

  15. The interplay of the Notch signaling in hepatic stellate cells and macrophages determines the fate of liver fibrogenesis

    NARCIS (Netherlands)

    Bansal, Ruchi; Baarlen, van 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 d

  16. 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...

  17. Unique molecular signatures influencing the biological function and fate of post-natal stem cells isolated from different sources.

    Science.gov (United States)

    Abu Kasim, Noor Hayaty; Govindasamy, Vijayendran; Gnanasegaran, Nareshwaran; Musa, Sabri; Pradeep, Padmaja Jayaprasad; Srijaya, Thekkeparambil Chandrabose; Aziz, Zeti Adura Che Ab

    2015-12-01

    The discovery of mesenchymal stem cells (MSCs) from a myriad of tissues has triggered the initiative of establishing tailor-made stem cells for disease-specific therapy. Nevertheless, lack of understanding on the inherent differential propensities of these cells may restrict their clinical outcome. Therefore, a comprehensive study was done to compare the proliferation, differentiation, expression of cell surface markers and gene profiling of stem cells isolated from different sources, viz. bone marrow, Wharton's jelly, adipose tissue and dental pulp. We found that although all MSCs were phenotypically similar to each other, Wharton's jelly (WJ) MSCs and dental pulp stem cells (DPSCs) were highly proliferative as compared to bone marrow (BM) MSCs and adipose tissue (AD) MSCs. Moreover, indistinguishable cell surface characteristics and differentiation capacity were confirmed to be similar among all cell types. Based on gene expression profiling, we postulate that BM-MSCs constitutively expressed genes related to inflammation and immunodulation, whereas genes implicated in tissue development were highly expressed in AD-MSCs. Furthermore, the transcriptome profiling of WJ-MSCs and DPSCs revealed an inherent bias towards the neuro-ectoderm lineage. Based on our findings, we believe that there is no unique master mesenchymal stem cell that is appropriate to treat all target diseases. More precisely, MSCs from different sources exhibit distinct and unique gene expression signatures that make them competent to give rise to specific lineages rather than others. Therefore, stem cells should be subjected to rigorous characterization and utmost vigilance needs to be adopted in order to choose the best cellular source for a particular disease.

  18. A dynamic complex of signaling proteins uses polar localization to regulate cell-fate asymmetry in Caulobacter crescentus.

    Science.gov (United States)

    Tsokos, Christos G; Perchuk, Barrett S; Laub, Michael T

    2011-03-15

    Cellular asymmetry is critical to metazoan development and the life cycle of many microbes. In Caulobacter, cell cycle progression and the formation of asymmetric daughter cells depend on the polarly-localized histidine kinase CckA. How CckA is regulated and why activity depends on localization are unknown. Here, we demonstrate that the unorthodox kinase DivL promotes CckA activity and that the phosphorylated regulator DivK inhibits CckA by binding to DivL. Early in the cell cycle, CckA is activated by the dephosphorylation of DivK throughout the cell. However, in later stages, when phosphorylated DivK levels are high, CckA activation relies on polar localization with a DivK phosphatase. Localization thus creates a protected zone for CckA within the cell, without the use of membrane-enclosed compartments. Our results reveal the mechanisms by which CckA is regulated in a cell-type-dependent manner. More generally, our findings reveal how cells exploit subcellular localization to orchestrate sophisticated regulatory processes.

  19. Epithelial cell fate in the nephron tubule is mediated by the ETS transcription factors etv5a and etv4 during zebrafish kidney development.

    Science.gov (United States)

    Marra, Amanda N; Wingert, Rebecca A

    2016-03-15

    Kidney development requires the differentiation and organization of discrete nephron epithelial lineages, yet the genetic and molecular pathways involved in these events remain poorly understood. The embryonic zebrafish kidney, or pronephros, provides a simple and useful model to study nephrogenesis. The pronephros is primarily comprised of two types of epithelial cells: transportive and multiciliated cells (MCCs). Transportive cells occupy distinct tubule segments and are characterized by the expression of various solute transporters, while MCCs function in fluid propulsion and are dispersed in a "salt-and-pepper" fashion within the tubule. Epithelial cell identity is reliant on interplay between the Notch signaling pathway and retinoic acid (RA) signaling, where RA promotes MCC fate by inhibiting Notch activity in renal progenitors, while Notch acts downstream to trigger transportive cell formation and block adoption of an MCC identity. Previous research has shown that the transcription factor ets variant 5a (etv5a), and its closely related ETS family members, are required for ciliogenesis in other zebrafish tissues. Here, we mapped etv5a expression to renal progenitors that occupy domains where MCCs later emerge. Thus, we hypothesized that etv5a is required for normal development of MCCs in the nephron. etv5a loss of function caused a decline of MCC number as indicated by the reduced frequency of cells that expressed the MCC-specific markers outer dense fiber of sperm tails 3b (odf3b) and centrin 4 (cetn4), where rescue experiments partially restored MCC incidence. Interestingly, deficiency of ets variant 4 (etv4), a related gene that is broadly expressed in the posterior mesoderm during somitogenesis stages, also led to reduced MCC numbers, which were further reduced by dual etv5a/4 deficiency, suggesting that both of these ETS factors are essential for MCC formation and that they also might have redundant activities. In epistatic studies, exogenous RA

  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

    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...... knockout islets is defective, highlighting a physiological role of iron and ROS in the regulation of insulin secretion. Dmt1 knockout mice are protected against multiple low-dose streptozotocin and high-fat diet-induced glucose intolerance, models of type 1 and type 2 diabetes, respectively. Thus, ß cells...

  1. NADPH oxidase-2 derived ROS dictates murine DC cytokine-mediated cell fate decisions during CD4 T helper-cell commitment.

    Directory of Open Access Journals (Sweden)

    Meghan A Jendrysik

    Full Text Available NADPH oxidase-2 (Nox2/gp91(phox and p47(phox deficient mice are prone to hyper-inflammatory responses suggesting a paradoxical role for Nox2-derived reactive oxygen species (ROS as anti-inflammatory mediators. The molecular basis for this mode of control remains unclear. Here we demonstrate that IFNγ/LPS matured p47(phox-/--ROS deficient mouse dendritic cells (DC secrete more IL-12p70 than similarly treated wild type DC, and in an in vitro co-culture model IFNγ/LPS matured p47(phox-/- DC bias more ovalbumin-specific CD4(+ T lymphocytes toward a Th1 phenotype than wild type (WT DC through a ROS-dependent mechanism linking IL-12p70 expression to regulation of p38-MAPK activation. The Nox2-dependent ROS production in DC negatively regulates proinflammatory IL-12 expression in DC by constraining p38-MAPK activity. Increasing endogenous H(2O(2 attenuates p38-MAPK activity in IFNγ/LPS stimulated WT and p47(phox-/- DC, which suggests that endogenous Nox 2-derived ROS functions as a secondary messenger in the activated p38-MAPK signaling pathway during IL-12 expression. These findings indicate that ROS, generated endogenously by innate and adaptive immune cells, can function as important secondary messengers that can regulate cytokine production and immune cell cross-talk to control during the inflammatory response.

  2. In-situ formation of growth-factor-loaded coacervate microparticle-embedded hydrogels for directing encapsulated stem cell fate.

    Science.gov (United States)

    Jeon, Oju; Wolfson, David W; Alsberg, Eben

    2015-04-01

    The spontaneous formation of coacervate microdroplet-laden photo-crosslinked hydrogels derived from the simple mixing of oxidized, methacrylated alginate (OMA) and methacrylated gelatin (GelMA) enables simultaneous creation of drug-laden microdroplets and encapsulation of stem cells in photopolymerized coacervate hydrogels under physiological conditions. This can be utilized as a novel platform for in situ formation of localized, sustained bioactive molecule delivery to encapsulate stem cells for therapeutic applications.

  3. Fate Specification of Neural Plate Border by Canonical Wnt Signaling and Grhl3 is Crucial for Neural Tube Closure.

    Science.gov (United States)

    Kimura-Yoshida, Chiharu; Mochida, Kyoko; Ellwanger, Kristina; Niehrs, Christof; Matsuo, Isao

    2015-06-01

    During primary neurulation, the separation of a single-layered ectodermal sheet into the surface ectoderm (SE) and neural tube specifies SE and neural ectoderm (NE) cell fates. The mechanisms underlying fate specification in conjunction with neural tube closure are poorly understood. Here, by comparing expression profiles between SE and NE lineages, we observed that uncommitted progenitor cells, expressing stem cell markers, are present in the neural plate border/neural fold prior to neural tube closure. Our results also demonstrated that canonical Wnt and its antagonists, DKK1/KREMEN1, progressively specify these progenitors into SE or NE fates in accord with the progress of neural tube closure. Additionally, SE specification of the neural plate border via canonical Wnt signaling is directed by the grainyhead-like 3 (Grhl3) transcription factor. Thus, we propose that the fate specification of uncommitted progenitors in the neural plate border by canonical Wnt signaling and its downstream effector Grhl3 is crucial for neural tube closure. This study implicates that failure in critical genetic factors controlling fate specification of progenitor cells in the neural plate border/neural fold coordinated with neural tube closure may be potential causes of human neural tube defects.

  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

    2015-07-15

    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.

  5. Genetic fate mapping of type-1 stem cell-dependent increase in newborn hippocampal neurons after electroconvulsive seizures.

    Science.gov (United States)

    Weber, Tillmann; Baier, Vera; Lentz, Katharina; Herrmann, Elke; Krumm, Bertram; Sartorius, Alexander; Kronenberg, Golo; Bartsch, Dusan

    2013-12-01

    Electroconvulsive therapy (ECT) is a uniquely effective treatment for major depressive disorder. An increase in hippocampal neurogenesis is implicated in the recovery from depression. We used an inducible genetic mouse model in which only GFAP-expressing stem-like cells (type-1 cells) and their progeny are selectively labeled with the reporter protein β-galactosidase to track the process of neurogenesis in the dentate gyrus over 3 months following electroconvulsive seizures (ECS), the mouse equivalent of ECT. All ECS protocols tested induced a transient increase in type-1 cell divisions. While this led to an expansion of the type-1 cell pool after high-frequency ECS sessions for 5 consecutive days (5-ECS), asymmetric divisions drove neurogenesis by giving rise to Doublecortin (DCX)-expressing neuroblasts that matured into NeuN+ neurons. Significantly, the increase in newly generated DCX+ and NeuN+ cells after 5-ECS could be traced back to proliferating type-1 cells. Low-frequency continuation ECS (c-ECS) consisting of five single ECS sessions administered every 2 weeks resulted in a similar increase in newborn neurons as the high-frequency 5-ECS protocol. Moreover, the combination of 5-ECS and c-ECS led to a further significant increase in newborn neurons, suggesting a cellular mechanism responsible for the propitious effects of high-frequency ECT followed by continuation ECT in severely depressed patients. The ability of high- and low-frequency ECS to induce normally quiescent type-1 cells to proliferate and generate new neurons sets it apart from other antidepressant treatments and may underlie the superior clinical efficacy of ECT.

  6. Developmental control of cell division

    NARCIS (Netherlands)

    Boxem, M. (Mike)

    2002-01-01

    During development of multicellular organisms, cell divisions need to be coordinated with the developmental program of the entire organism. Although the mechanisms that drive cells through the division cycle are well understood, very little is known about the pathways that link extracellular signals

  7. 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...

  8. A role for interleukin-1β in determining the lineage fate of embryonic rat hippocampal neural precursor cells.

    Science.gov (United States)

    Green, Holly F; Treacy, Eimear; Keohane, Aoife K; Sullivan, Aideen M; O'Keeffe, Gerard W; Nolan, Yvonne M

    2012-03-01

    Neurogenesis occurs in the hippocampus of the developing and adult brain due to the presence of multipotent stem cells and restricted precursor cells at different stages of differentiation. It has been proposed that they may be of potential benefit for use in cell transplantation approaches for neurodegenerative disorders and trauma. Prolonged release of interleukin-1β (IL-1β) from activated microglia has a deleterious effect on hippocampal neurons and is implicated in the impaired neurogenesis and cognitive dysfunction associated with aging, Alzheimer's disease and depression. This study assessed the effect of IL-1β on the proliferation and differentiation of embryonic rat hippocampal NPCs in vitro. We show that IL-1R1 is expressed on proliferating NPCs and that IL-1β treatment decreases cell proliferation and neurosphere growth. When NPCs were differentiated in the presence of IL-1β, a significant reduction in the percentages of newly-born neurons and post-mitotic neurons and a significant increase in the percentage of astrocytes was observed in these cultures. These effects were attenuated by IL-1 receptor antagonist. These data reveal that IL-1β exerts an anti-proliferative, anti-neurogenic and pro-gliogenic effect on embryonic hippocampal NPCs, which is mediated by IL-1R1. The present results emphasise the consequences of an inflammatory environment during NPC development, and indicate that strategies to inhibit IL-1β signalling may be necessary to facilitate effective cell transplantation approaches or in conditions where endogenous hippocampal neurogenesis is impaired.

  9. Tracking the stochastic fate of cells of the renin lineage after podocyte depletion using multicolor reporters and intravital imaging.

    Science.gov (United States)

    Kaverina, Natalya V; Kadoya, Hiroyuki; Eng, Diana G; Rusiniak, Michael E; Sequeira-Lopez, Maria Luisa S; Gomez, R Ariel; Pippin, Jeffrey W; Gross, Kenneth W; Peti-Peterdi, Janos; Shankland, Stuart J

    2017-01-01

    Podocyte depletion plays a major role in focal segmental glomerular sclerosis (FSGS). Because cells of the renin lineage (CoRL) serve as adult podocyte and parietal epithelial cell (PEC) progenitor candidates, we generated Ren1cCre/R26R-ConfettiTG/WT and Ren1dCre/R26R-ConfettiTG/WT mice to determine CoRL clonality during podocyte replacement. Four CoRL reporters (GFP, YFP, RFP, CFP) were restricted to cells in the juxtaglomerular compartment (JGC) at baseline. Following abrupt podocyte depletion in experimental FSGS, all four CoRL reporters were detected in a subset of glomeruli at day 28, where they co-expressed de novo four podocyte proteins (podocin, nephrin, WT-1 and p57) and two glomerular parietal epithelial cell (PEC) proteins (claudin-1, PAX8). To monitor the precise migration of a subset of CoRL over a 2w period following podocyte depletion, intravital multiphoton microscopy was used. Our findings demonstrate direct visual support for the migration of single CoRL from the JGC to the parietal Bowman's capsule, early proximal tubule, mesangium and glomerular tuft. In summary, these results suggest that following podocyte depletion, multi-clonal CoRL migrate to the glomerulus and replace podocyte and PECs in experimental FSGS.

  10. In vivo fate mapping and expression analysis reveals molecular hallmarks of prospectively isolated adult neural stem cells.

    Science.gov (United States)

    Beckervordersandforth, Ruth; Tripathi, Pratibha; Ninkovic, Jovica; Bayam, Efil; Lepier, Alexandra; Stempfhuber, Barbara; Kirchhoff, Frank; Hirrlinger, Johannes; Haslinger, Anja; Lie, D Chichung; Beckers, Johannes; Yoder, Bradley; Irmler, Martin; Götz, Magdalena

    2010-12-03

    Until now, limitations in the ability to enrich adult NSCs (aNSCs) have hampered meaningful analysis of these cells at the transcriptome level. Here we show via a split-Cre technology that coincident activity of the hGFAP and prominin1 promoters is a hallmark of aNSCs in vivo. Sorting of cells from the adult mouse subependymal zone (SEZ) based on their expression of GFAP and prominin1 isolates all self-renewing, multipotent stem cells at high purity. Comparison of the transcriptome of these purified aNSCs to parenchymal nonneurogenic astrocytes and other SEZ cells reveals aNSC hallmarks, including neuronal lineage priming and the importance of cilia- and Ca-dependent signaling pathways. Inducible deletion of the ciliary protein IFT88 in aNSCs validates the role of ciliary function in aNSCs. Our work reveals candidate molecular regulators for unique features of aNSCs and facilitates future selective analysis of aNSCs in other functional contexts, such as aging and injury.

  11. Profiling a gut microbiota-generated catechin metabolite's fate in human blood cells using a metabolomic approach.

    Science.gov (United States)

    Mülek, Melanie; Fekete, Agnes; Wiest, Johannes; Holzgrabe, Ulrike; Mueller, Martin J; Högger, Petra

    2015-10-10

    The microbial catechin metabolite δ-(3,4-dihydroxy-phenyl)-γ-valerolactone (M1) has been found in human plasma samples after intake of maritime pine bark extract (Pycnogenol). M1 has been previously shown to accumulate in endothelial and blood cells in vitro after facilitated uptake and to exhibit anti-inflammatory activity. The purpose of the present research approach was to systematically and comprehensively analyze the metabolism of M1 in human blood cells in vitro and in vivo. A metabolomic approach that had been successfully applied for drug metabolite profiling was chosen to detect 19 metabolite peaks of M1 which were subsequently further analyzed and validated. The metabolites were categorized into three levels of identification according to the Metabolomics Standards Initiative with six compounds each confirmed at levels 1 and 2 and seven putative metabolites at level 3. The predominant metabolites were glutathione conjugates which were rapidly formed and revealed prolonged presence within the cells. Although a formation of an intracellular conjugate of M1 and glutathione (M1-GSH) was already known two GSH conjugate isomers, M1-S-GSH and M1-N-GSH were observed in the current study. Additionally detected organosulfur metabolites were conjugates with oxidized glutathione and cysteine. Other biotransformation products constituted the open-chained ester form of M1 and a methylated M1. Six of the metabolites determined in in vitro assays were also detected in blood cells in vivo after ingestion of the pine bark extract by two volunteers. The present study provides the first evidence that multiple and structurally heterogeneous polyphenol metabolites can be generated in human blood cells. The bioactivity of the M1 metabolites and their contribution to the previously determined anti-inflammatory effects of M1 now need to be elucidated.

  12. Nitric oxide-induced murine hematopoietic stem cell fate involves multiple signaling proteins, gene expression, and redox modulation.

    Science.gov (United States)

    Nogueira-Pedro, Amanda; Dias, Carolina C; Regina, Helena; Segreto, C; Addios, Priscilla C; Lungato, Lisandro; D'Almeida, Vania; Barros, Carlos C; Higa, Elisa M S; Buri, Marcus V; Ferreira, Alice T; Paredes-Gamero, Edgar Julian

    2014-11-01

    There are a growing number of reports showing the influence of redox modulation in cellular signaling. Although the regulation of hematopoiesis by reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been described, their direct participation in the differentiation of hematopoietic stem cells (HSCs) remains unclear. In this work, the direct role of nitric oxide (NO(•)), a RNS, in the modulation of hematopoiesis was investigated using two sources of NO(•) , one produced by endothelial cells stimulated with carbachol in vitro and another using the NO(•)-donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP) in vivo. Two main NO(•) effects were observed: proliferation of HSCs-especially of the short-term HSCs-and its commitment and terminal differentiation to the myeloid lineage. NO(•)-induced proliferation was characterized by the increase in the number of cycling HSCs and hematopoietic progenitor cells positive to BrdU and Ki-67, upregulation of Notch-1, Cx43, PECAM-1, CaR, ERK1/2, Akt, p38, PKC, and c-Myc. NO(•)-induced HSCs differentiation was characterized by the increase in granulocytic-macrophage progenitors, granulocyte-macrophage colony forming units, mature myeloid cells, upregulation of PU.1, and C/EBPα genes concomitantly to the downregulation of GATA-3 and Ikz-3 genes, activation of Stat5 and downregulation of the other analyzed proteins mentioned above. Also, redox status modulation differed between proliferation and differentiation responses, which is likely associated with the transition of the proliferative to differentiation status. Our findings provide evidence of the role of NO(•) in inducing HSCs proliferation and myeloid differentiation involving multiple signaling.

  13. 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

    Directory of Open Access Journals (Sweden)

    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 embr