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Sample records for activate stem cells

  1. Dormancy activation mechanism of tracheal stem cells

    PubMed Central

    Li, Xin; Xu, Jing-xian; Jia, Xin-Shan; Li, Wen-ya; Han, Yi-chen; Wang, En-hua; Li, Fang

    2016-01-01

    Accurate markers and molecular mechanisms of stem cell dormancy and activation are poorly understood. In this study, the anti-cancer drug, 5-fluorouracil, was used to selectively kill proliferating cells of human bronchial epithelial (HBE) cell line. This method can enrich and purify stem cell population. The dormant versus active status of stem cells was determined by phosphorylation of RNAp II Ser2. The surviving stem cells were cultured to form stem cell spheres expressing stem cell markers and transplanted into nude mice to form a teratoma. The results demonstrated the properties of stem cells and potential for multi-directional differentiation. Bisulfite sequencing polymerase chain reaction showed that demethylation of the Sox2 promoter by 5-FU resulted in Sox2 expression in the dormant stem cells. This study shows that the dormancy and activation of HBE stem cells is closely related to epigenetic modification. PMID:27009861

  2. Stem cell tracking with optically active nanoparticles

    PubMed Central

    Gao, Yu; Cui, Yan; Chan, Jerry KY; Xu, Chenjie

    2013-01-01

    Stem-cell-based therapies hold promise and potential to address many unmet clinical needs. Cell tracking with modern imaging modalities offers insight into the underlying biological process of the stem-cell-based therapies, with the goal to reveal cell survival, migration, homing, engraftment, differentiation, and functions. Adaptability, sensitivity, resolution, and non-invasiveness have contributed to the longstanding use of optical imaging for stem cell tracking and analysis. To identify transplanted stem cells from the host tissue, optically active probes are usually used to label stem cells before the administration. In comparison to the traditional fluorescent probes like fluorescent proteins and dyes, nanoparticle-based probes are advantageous in terms of the photo-stabilities and minimal changes to the cell phenotype. The main focus here is to overview the recent development of optically active nanoparticles for stem cells tracking. The related optical imaging modalities include fluorescence imaging, photoacoustic imaging, Raman and surface enhanced Raman spectroscopy imaging. PMID:23638335

  3. Chronic variable stress activates hematopoietic stem cells

    PubMed Central

    Courties, Gabriel; Dutta, Partha; Iwamoto, Yoshiko; Zaltsman, Alex; von zur Muhlen, Constantin; Bode, Christoph; Fricchione, Gregory L.; Denninger, John; Lin, Charles P.; Vinegoni, Claudio; Libby, Peter; Swirski, Filip K.; Weissleder, Ralph; Nahrendorf, Matthias

    2014-01-01

    Exposure to psychosocial stress is a risk factor for many diseases, including atherosclerosis1,2. While incompletely understood, interaction between the psyche and the immune system provides one potential mechanism linking stress and disease inception and progression. Known crosstalk between the brain and immune system includes the hypothalamic–pituitary–adrenal axis, which centrally drives glucocorticoid production in the adrenal cortex, and the sympathetic–adrenal–medullary axis, which controls stress–induced catecholamine release in support of the fight–or–flight reflex3,4. It remains unknown however if chronic stress changes hematopoietic stem cell activity. Here we show that stress increases proliferation of these most primitive progenitors, giving rise to higher levels of disease–promoting inflammatory leukocytes. We found that chronic stress induced monocytosis and neutrophilia in humans. While investigating the source of leukocytosis in mice, we discovered that stress activates upstream hematopoietic stem cells. Sympathetic nerve fibers release surplus noradrenaline, which uses the β3 adrenergic receptor to signal bone marrow niche cells to decrease CXCL12 levels. Consequently, elevated hematopoietic stem cell proliferation increases output of neutrophils and inflammatory monocytes. When atherosclerosis–prone ApoE−/− mice encounter chronic stress, accelerated hematopoiesis promotes plaque features associated with vulnerable lesions that cause myocardial infarction and stroke in humans. PMID:24952646

  4. Stem Cells

    MedlinePlus

    Stem cells are cells with the potential to develop into many different types of cells in the body. They serve as a repair ... body. There are two main types of stem cells: embryonic stem cells and adult stem cells. Stem ...

  5. Immunomodulation of activated hepatic stellate cells by mesenchymal stem cells

    SciTech Connect

    Parekkadan, Biju; Poll, Daan van; Megeed, Zaki; Kobayashi, Naoya; Tilles, Arno W.; Berthiaume, Francois; Yarmush, Martin L.

    2007-11-16

    Bone marrow-derived mesenchymal stem cells (MSCs) have been reported to prevent the development of liver fibrosis in a number of pre-clinical studies. Marked changes in liver histopathology and serological markers of liver function have been observed without a clear understanding of the therapeutic mechanism by which stem cells act. We sought to determine if MSCs could modulate the activity of resident liver cells, specifically hepatic stellate cells (SCs) by paracrine mechanisms using indirect cocultures. Indirect coculture of MSCs and activated SCs led to a significant decrease in collagen deposition and proliferation, while inducing apoptosis of activated SCs. The molecular mechanisms underlying the modulation of SC activity by MSCs were examined. IL-6 secretion from activated SCs induced IL-10 secretion from MSCs, suggesting a dynamic response of MSCs to the SCs in the microenvironment. Blockade of MSC-derived IL-10 and TNF-{alpha} abolished the inhibitory effects of MSCs on SC proliferation and collagen synthesis. In addition, release of HGF by MSCs was responsible for the marked induction of apoptosis in SCs as determined by antibody-neutralization studies. These findings demonstrate that MSCs can modulate the function of activated SCs via paracrine mechanisms provide a plausible explanation for the protective role of MSCs in liver inflammation and fibrosis, which may also be relevant to other models of tissue fibrosis.

  6. Functionally Active Gap Junctions between Connexin 43-Positive Mesenchymal Stem Cells and Glioma Cells.

    PubMed

    Gabashvili, A N; Baklaushev, V P; Grinenko, N F; Levinskii, A B; Mel'nikov, P A; Cherepanov, S A; Chekhonin, V P

    2015-05-01

    The formation of functional gap junctions between mesenchymal stem cells and cells of low-grade rat glioma C6 cells was studied in in vitro experiments. Immunocytochemical analysis with antibodies to connexin 43 extracellular loop 2 showed that mesenchymal stem cells as well as C6 glioma cells express the main astroglial gap junction protein connexin 43. Analysis of migration activity showed that mesenchymal stem cells actively migrate towards C6 glioma cells. During co-culturing, mesenchymal stem cells and glioma C6 form functionally active gap junctions mediating the transport of cytoplasmic dye from glioma cells to mesenchymal stem cells in the opposite direction. Fluorometry showed that the intensity of transport of low-molecular substances through heterologous gap junctions between mesenchymal stem cells and glioma cells is similar to that through homologous gap junctions between glioma cells. This phenomenon can be used for the development of new methods of cell therapy of high-grade gliomas.

  7. Types of Stem Cells

    MedlinePlus

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... stem cells blog from the International Society for Stem Cell Research. Learn About Stem Cells From Lab to You ...

  8. Endothelial juxtaposition of distinct adult stem cells activates angiogenesis signaling molecules in endothelial cells.

    PubMed

    Mohammadi, Elham; Nassiri, Seyed Mahdi; Rahbarghazi, Reza; Siavashi, Vahid; Araghi, Atefeh

    2015-12-01

    Efficacy of therapeutic angiogenesis needs a comprehensive understanding of endothelial cell (EC) function and biological factors and cells that interplay with ECs. Stem cells are considered the key components of pro- and anti-angiogenic milieu in a wide variety of physiopathological states, and interactions of EC-stem cells have been the subject of controversy in recent years. In this study, the potential effects of three tissue-specific adult stem cells, namely rat marrow-derived mesenchymal stem cells (rBMSCs), rat adipose-derived stem cells (rADSCs) and rat muscle-derived satellite cells (rSCs), on the endothelial activation of key angiogenic signaling molecules, including VEGF, Ang-2, VEGFR-2, Tie-2, and Tie2-pho, were investigated. Human umbilical vein endothelial cells (HUVECs) and rat lung microvascular endothelial cells (RLMECs) were cocultured with the stem cells or incubated with the stem cell-derived conditioned media on Matrigel. Following HUVEC-stem cell coculture, CD31-positive ECs were flow sorted and subjected to western blotting to analyze potential changes in the expression of the pro-angiogenic signaling molecules. Elongation and co-alignment of the stem cells were seen along the EC tubes in the EC-stem cell cocultures on Matrigel, with cell-to-cell dye communication in the EC-rBMSC cocultures. Moreover, rBMSCs and rADSCs significantly improved endothelial tubulogenesis in both juxtacrine and paracrine manners. These two latter stem cells dynamically up-regulated VEGF, Ang-2, VREGR-2, and Tie-2 but down-regulated Tie2-pho and the Tie2-pho/Tie-2 ratio in HUVECs. Induction of pro-angiogenic signaling in ECs by marrow- and adipose-derived MSCs further indicates the significance of stem cell milieu in angiogenesis dynamics. PMID:26068799

  9. Stem cell biobanks.

    PubMed

    Bardelli, Silvana

    2010-04-01

    Stem cells contribute to innate healing and harbor a promising role for regenerative medicine. Stem cell banking through long-term storage of different stem cell platforms represents a fundamental source to preserve original features of stem cells for patient-specific clinical applications. Stem cell research and clinical translation constitute fundamental and indivisible modules catalyzed through biobanking activity, generating a return of investment. PMID:20560026

  10. Stem cell cytoskeleton is slaved to active motors

    NASA Astrophysics Data System (ADS)

    Rehfeldt, Florian; Brown, Andre; Engler, Adam; Discher, Dennis

    2007-03-01

    Cells feel their physical microenvironment through their adhesion and respond to it in various ways. Indeed, matrix elasticity can even guide the differentiation of human adult mesenchymal stem cells (MSCs) [Engler et al. Cell 2006]. Sparse cultures of MSCs on elastic collagen--coated substrates that are respectively soft, stiff, or extremely stiff were shown to induce neurogenesis, myogenesis, and osteogenesis. Lineage commitment was evaluated by morphological analysis, protein expression profiles, and transcription microarrays. Differentiation could be completely blocked with a specific non-muscle myosin II (NMM II) inhibitor, suggesting that contractile motor activity is essential for the cells to sense matrix elasticity. Current studies by AFM and near-field fluorescence imaging show that NMM II inhibition in stem cells on rigid glass surfaces promotes actin-rich dendritic outgrowth resembling neurite extension. Dynamic cell studies have been conducted to elucidate the complex molecular interplay of the contractile apparatus in response to selected physical and biochemical stimuli. Additional insight is being gained by using AFM to investigate the local elasticity of the cell's cytoskeletal force sensing machinery.

  11. A transcriptional mechanism integrating inputs from extracellular signals to activate hippocampal stem cells.

    PubMed

    Andersen, Jimena; Urbán, Noelia; Achimastou, Angeliki; Ito, Ayako; Simic, Milesa; Ullom, Kristy; Martynoga, Ben; Lebel, Mélanie; Göritz, Christian; Frisén, Jonas; Nakafuku, Masato; Guillemot, François

    2014-09-01

    The activity of adult stem cells is regulated by signals emanating from the surrounding tissue. Many niche signals have been identified, but it is unclear how they influence the choice of stem cells to remain quiescent or divide. Here we show that when stem cells of the adult hippocampus receive activating signals, they first induce the expression of the transcription factor Ascl1 and only subsequently exit quiescence. Moreover, lowering Ascl1 expression reduces the proliferation rate of hippocampal stem cells, and inactivating Ascl1 blocks quiescence exit completely, rendering them unresponsive to activating stimuli. Ascl1 promotes the proliferation of hippocampal stem cells by directly regulating the expression of cell-cycle regulatory genes. Ascl1 is similarly required for stem cell activation in the adult subventricular zone. Our results support a model whereby Ascl1 integrates inputs from both stimulatory and inhibitory signals and converts them into a transcriptional program activating adult neural stem cells.

  12. A Transcriptional Mechanism Integrating Inputs from Extracellular Signals to Activate Hippocampal Stem Cells

    PubMed Central

    Andersen, Jimena; Urbán, Noelia; Achimastou, Angeliki; Ito, Ayako; Simic, Milesa; Ullom, Kristy; Martynoga, Ben; Lebel, Mélanie; Göritz, Christian; Frisén, Jonas; Nakafuku, Masato; Guillemot, François

    2014-01-01

    Summary The activity of adult stem cells is regulated by signals emanating from the surrounding tissue. Many niche signals have been identified, but it is unclear how they influence the choice of stem cells to remain quiescent or divide. Here we show that when stem cells of the adult hippocampus receive activating signals, they first induce the expression of the transcription factor Ascl1 and only subsequently exit quiescence. Moreover, lowering Ascl1 expression reduces the proliferation rate of hippocampal stem cells, and inactivating Ascl1 blocks quiescence exit completely, rendering them unresponsive to activating stimuli. Ascl1 promotes the proliferation of hippocampal stem cells by directly regulating the expression of cell-cycle regulatory genes. Ascl1 is similarly required for stem cell activation in the adult subventricular zone. Our results support a model whereby Ascl1 integrates inputs from both stimulatory and inhibitory signals and converts them into a transcriptional program activating adult neural stem cells. PMID:25189209

  13. Haemocytes control stem cell activity in the Drosophila intestine.

    PubMed

    Ayyaz, Arshad; Li, Hongjie; Jasper, Heinrich

    2015-06-01

    Coordination of stem cell activity with inflammatory responses is critical for regeneration and homeostasis of barrier epithelia. The temporal sequence of cell interactions during injury-induced regeneration is only beginning to be understood. Here we show that intestinal stem cells (ISCs) are regulated by macrophage-like haemocytes during the early phase of regenerative responses of the Drosophila intestinal epithelium. On tissue damage, haemocytes are recruited to the intestine and secrete the BMP homologue DPP, inducing ISC proliferation by activating the type I receptor Saxophone and the Smad homologue SMOX. Activated ISCs then switch their response to DPP by inducing expression of Thickveins, a second type I receptor that has previously been shown to re-establish ISC quiescence by activating MAD. The interaction between haemocytes and ISCs promotes infection resistance, but also contributes to the development of intestinal dysplasia in ageing flies. We propose that similar interactions influence pathologies such as inflammatory bowel disease and colorectal cancer in humans. PMID:26005834

  14. Haemocytes control stem cell activity in the Drosophila intestine.

    PubMed

    Ayyaz, Arshad; Li, Hongjie; Jasper, Heinrich

    2015-06-01

    Coordination of stem cell activity with inflammatory responses is critical for regeneration and homeostasis of barrier epithelia. The temporal sequence of cell interactions during injury-induced regeneration is only beginning to be understood. Here we show that intestinal stem cells (ISCs) are regulated by macrophage-like haemocytes during the early phase of regenerative responses of the Drosophila intestinal epithelium. On tissue damage, haemocytes are recruited to the intestine and secrete the BMP homologue DPP, inducing ISC proliferation by activating the type I receptor Saxophone and the Smad homologue SMOX. Activated ISCs then switch their response to DPP by inducing expression of Thickveins, a second type I receptor that has previously been shown to re-establish ISC quiescence by activating MAD. The interaction between haemocytes and ISCs promotes infection resistance, but also contributes to the development of intestinal dysplasia in ageing flies. We propose that similar interactions influence pathologies such as inflammatory bowel disease and colorectal cancer in humans.

  15. Activation of endogenous neural stem cells for multiple sclerosis therapy.

    PubMed

    Michailidou, Iliana; de Vries, Helga E; Hol, Elly M; van Strien, Miriam E

    2014-01-01

    Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system, leading to severe neurological deficits. Current MS treatment regimens, consist of immunomodulatory agents aiming to reduce the rate of relapses. However, these agents are usually insufficient to treat chronic neurological disability. A promising perspective for future therapy of MS is the regeneration of lesions with replacement of the damaged oligodendrocytes or neurons. Therapies targeting to the enhancement of endogenous remyelination, aim to promote the activation of either the parenchymal oligodendrocyte progenitor cells or the subventricular zone-derived neural stem cells (NSCs). Less studied but highly potent, is the strategy of neuronal regeneration with endogenous NSCs that although being linked to numerous limitations, is anticipated to ameliorate cognitive disability in MS. Focusing on the forebrain, this review highlights the role of NSCs in the regeneration of MS lesions.

  16. Activation of endogenous neural stem cells for multiple sclerosis therapy

    PubMed Central

    Michailidou, Iliana; de Vries, Helga E.; Hol, Elly M.; van Strien, Miriam E.

    2015-01-01

    Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system, leading to severe neurological deficits. Current MS treatment regimens, consist of immunomodulatory agents aiming to reduce the rate of relapses. However, these agents are usually insufficient to treat chronic neurological disability. A promising perspective for future therapy of MS is the regeneration of lesions with replacement of the damaged oligodendrocytes or neurons. Therapies targeting to the enhancement of endogenous remyelination, aim to promote the activation of either the parenchymal oligodendrocyte progenitor cells or the subventricular zone-derived neural stem cells (NSCs). Less studied but highly potent, is the strategy of neuronal regeneration with endogenous NSCs that although being linked to numerous limitations, is anticipated to ameliorate cognitive disability in MS. Focusing on the forebrain, this review highlights the role of NSCs in the regeneration of MS lesions. PMID:25653584

  17. Epac Activation Regulates Human Mesenchymal Stem Cells Migration and Adhesion.

    PubMed

    Yu, Jiao-Le; Deng, Ruixia; Chung, Sookja K; Chan, Godfrey Chi-Fung

    2016-04-01

    How to enhance the homing of human mesenchymal stem cells (hMSCs) to the target tissues remains a clinical challenge nowadays. To overcome this barrier, the mechanism responsible for the hMSCs migration and engraftment has to be defined. Currently, the exact mechanism involved in migration and adhesion of hMSCs remains unknown. Exchange protein directly activated by cAMP (Epac), a novel protein discovered in cAMP signaling pathway, may have a potential role in regulating cells adhesion and migration by triggering the downstream Rap family signaling cascades. However, the exact role of Epac in cells homing is elusive. Our study evaluated the role of Epac in the homing of hMSCs. We confirmed that hMSCs expressed functional Epac and its activation enhanced the migration and adhesion of hMSCs significantly. The Epac activation was further found to be contributed directly to the chemotactic responses induced by stromal cell derived factor-1 (SDF-1) which is a known chemokine in regulating hMSCs homing. These findings suggested Epac is connected to the SDF-1 signaling cascades. In conclusion, our study revealed that Epac plays a role in hMSCs homing by promoting adhesion and migration. Appropriate manipulation of Epac may enhance the homing of hMSCs and facilitate their future clinical applications. PMID:26727165

  18. Stem Cell Basics

    MedlinePlus

    ... stem cells? What are the potential uses of human stem cells and the obstacles that must be overcome before ... two kinds of stem cells from animals and humans: embryonic stem cells and non-embryonic "somatic" or "adult" stem cells . ...

  19. Learn About Stem Cells

    MedlinePlus

    ... PDF) Download an introduction to stem cells and stem cell research. Stem Cell Glossary Stem cell terms to know. ... ISSCR Get Involved Media © 2015 International Society for Stem Cell Research Terms of Use Disclaimer Privacy Policy

  20. Plant stem cell niches.

    PubMed

    Aichinger, Ernst; Kornet, Noortje; Friedrich, Thomas; Laux, Thomas

    2012-01-01

    Multicellular organisms possess pluripotent stem cells to form new organs, replenish the daily loss of cells, or regenerate organs after injury. Stem cells are maintained in specific environments, the stem cell niches, that provide signals to block differentiation. In plants, stem cell niches are situated in the shoot, root, and vascular meristems-self-perpetuating units of organ formation. Plants' lifelong activity-which, as in the case of trees, can extend over more than a thousand years-requires that a robust regulatory network keep the balance between pluripotent stem cells and differentiating descendants. In this review, we focus on current models in plant stem cell research elaborated during the past two decades, mainly in the model plant Arabidopsis thaliana. We address the roles of mobile signals on transcriptional modules involved in balancing cell fates. In addition, we discuss shared features of and differences between the distinct stem cell niches of Arabidopsis.

  1. Integration of light and metabolic signals for stem cell activation at the shoot apical meristem

    PubMed Central

    Pfeiffer, Anne; Janocha, Denis; Dong, Yihan; Medzihradszky, Anna; Schöne, Stefanie; Daum, Gabor; Suzaki, Takuya; Forner, Joachim; Langenecker, Tobias; Rempel, Eugen; Schmid, Markus; Wirtz, Markus; Hell, Rüdiger; Lohmann, Jan U

    2016-01-01

    A major feature of embryogenesis is the specification of stem cell systems, but in contrast to the situation in most animals, plant stem cells remain quiescent until the postembryonic phase of development. Here, we dissect how light and metabolic signals are integrated to overcome stem cell dormancy at the shoot apical meristem. We show on the one hand that light is able to activate expression of the stem cell inducer WUSCHEL independently of photosynthesis and that this likely involves inter-regional cytokinin signaling. Metabolic signals, on the other hand, are transduced to the meristem through activation of the TARGET OF RAPAMYCIN (TOR) kinase. Surprisingly, TOR is also required for light signal dependent stem cell activation. Thus, the TOR kinase acts as a central integrator of light and metabolic signals and a key regulator of stem cell activation at the shoot apex. DOI: http://dx.doi.org/10.7554/eLife.17023.001 PMID:27400267

  2. Integration of light and metabolic signals for stem cell activation at the shoot apical meristem.

    PubMed

    Pfeiffer, Anne; Janocha, Denis; Dong, Yihan; Medzihradszky, Anna; Schöne, Stefanie; Daum, Gabor; Suzaki, Takuya; Forner, Joachim; Langenecker, Tobias; Rempel, Eugen; Schmid, Markus; Wirtz, Markus; Hell, Rüdiger; Lohmann, Jan U

    2016-01-01

    A major feature of embryogenesis is the specification of stem cell systems, but in contrast to the situation in most animals, plant stem cells remain quiescent until the postembryonic phase of development. Here, we dissect how light and metabolic signals are integrated to overcome stem cell dormancy at the shoot apical meristem. We show on the one hand that light is able to activate expression of the stem cell inducer WUSCHEL independently of photosynthesis and that this likely involves inter-regional cytokinin signaling. Metabolic signals, on the other hand, are transduced to the meristem through activation of the TARGET OF RAPAMYCIN (TOR) kinase. Surprisingly, TOR is also required for light signal dependent stem cell activation. Thus, the TOR kinase acts as a central integrator of light and metabolic signals and a key regulator of stem cell activation at the shoot apex. PMID:27400267

  3. Caspase activity mediates the differentiation of embryonic stem cells

    PubMed Central

    Fujita, Jun; Crane, Ana M.; Souza, Marlon K.; Dejosez, Marion; Kyba, Michael; Flavell, Richard A.; Thomson, James A.; Zwaka, Thomas P.

    2008-01-01

    Summary Embryonic stem (ES) cells are capable of indefinite self-renewal while retaining the ability to differentiate to any of the three germ layers that give rise to all somatic cell types. An emerging view is that a core set of transcription factors, including Oct4, Sox2 and Nanog, form a robust autoregulatory circuit that maintains ES cells in a self-renewing state. To accommodate the capacity of such cells to undergo germ layer-specific differentiation, we predicted a post-translational mechanism that could negatively regulate these core self-renewal factors. Here we report caspase-induced cleavage of Nanog in differentiating ES cells. Stem cells lacking the Casp3 gene showed marked defects in differentiation, while forced expression of a caspase cleavage-resistant Nanog mutant in ES cells strongly promoted self-renewal. These results link a major component of the programmed cell death pathway to the regulation of ES cell development. PMID:18522852

  4. Runx1 modulates developmental, but not injury-driven, hair follicle stem cell activation.

    PubMed

    Osorio, Karen M; Lee, Song Eun; McDermitt, David J; Waghmare, Sanjeev K; Zhang, Ying V; Woo, Hyun Nyun; Tumbar, Tudorita

    2008-03-01

    Aml1/Runx1 controls developmental aspects of several tissues, is a master regulator of blood stem cells, and plays a role in leukemia. However, it is unclear whether it functions in tissue stem cells other than blood. Here, we have investigated the role of Runx1 in mouse hair follicle stem cells by conditional ablation in epithelial cells. Runx1 disruption affects hair follicle stem cell activation, but not their maintenance, proliferation or differentiation potential. Adult mutant mice exhibit impaired de novo production of hair shafts and all temporary hair cell lineages, owing to a prolonged quiescent phase of the first hair cycle. The lag of stem cell activity is reversed by skin injury. Our work suggests a degree of functional overlap in Runx1 regulation of blood and hair follicle stem cells at an equivalent time point in the development of these two tissues. PMID:18256199

  5. Runx1 modulates developmental, but not injury-driven, hair follicle stem cell activation.

    PubMed

    Osorio, Karen M; Lee, Song Eun; McDermitt, David J; Waghmare, Sanjeev K; Zhang, Ying V; Woo, Hyun Nyun; Tumbar, Tudorita

    2008-03-01

    Aml1/Runx1 controls developmental aspects of several tissues, is a master regulator of blood stem cells, and plays a role in leukemia. However, it is unclear whether it functions in tissue stem cells other than blood. Here, we have investigated the role of Runx1 in mouse hair follicle stem cells by conditional ablation in epithelial cells. Runx1 disruption affects hair follicle stem cell activation, but not their maintenance, proliferation or differentiation potential. Adult mutant mice exhibit impaired de novo production of hair shafts and all temporary hair cell lineages, owing to a prolonged quiescent phase of the first hair cycle. The lag of stem cell activity is reversed by skin injury. Our work suggests a degree of functional overlap in Runx1 regulation of blood and hair follicle stem cells at an equivalent time point in the development of these two tissues.

  6. Genetic abolishment of hepatocyte proliferation activates hepatic stem cells.

    PubMed

    Endo, Yoko; Zhang, Mingjun; Yamaji, Sachie; Cang, Yong

    2012-01-01

    Quiescent hepatic stem cells (HSCs) can be activated when hepatocyte proliferation is compromised. Chemical injury rodent models have been widely used to study the localization, biomarkers, and signaling pathways in HSCs, but these models usually exhibit severe promiscuous toxicity and fail to distinguish damaged and non-damaged cells. Our goal is to establish new animal models to overcome these limitations, thereby providing new insights into HSC biology and application. We generated mutant mice with constitutive or inducible deletion of Damaged DNA Binding protein 1 (DDB1), an E3 ubiquitin ligase, in hepatocytes. We characterized the molecular mechanism underlying the compensatory activation and the properties of oval cells (OCs) by methods of mouse genetics, immuno-staining, cell transplantation and gene expression profiling. We show that deletion of DDB1 abolishes self-renewal capacity of mouse hepatocytes in vivo, leading to compensatory activation and proliferation of DDB1-expressing OCs. Partially restoring proliferation of DDB1-deficient hepatocytes by ablation of p21, a substrate of DDB1 E3 ligase, alleviates OC proliferation. Purified OCs express both hepatocyte and cholangiocyte markers, form colonies in vitro, and differentiate to hepatocytes after transplantation. Importantly, the DDB1 mutant mice exhibit very minor liver damage, compared to a chemical injury model. Microarray analysis reveals several previously unrecognized markers, including Reelin, enriched in oval cells. Here we report a genetic model in which irreversible inhibition of hepatocyte duplication results in HSC-driven liver regeneration. The DDB1 mutant mice can be broadly applied to studies of HSC differentiation, HSC niche and HSCs as origin of liver cancer. PMID:22384083

  7. Jarid2 regulates mouse epidermal stem cell activation and differentiation.

    PubMed

    Mejetta, Stefania; Morey, Lluis; Pascual, Gloria; Kuebler, Bernd; Mysliwiec, Matthew R; Lee, Youngsook; Shiekhattar, Ramin; Di Croce, Luciano; Benitah, Salvador Aznar

    2011-08-02

    Jarid2 is required for the genomic recruitment of the polycomb repressive complex-2 (PRC2) in embryonic stem cells. However, its specific role during late development and adult tissues remains largely uncharacterized. Here, we show that deletion of Jarid2 in mouse epidermis reduces the proliferation and potentiates the differentiation of postnatal epidermal progenitors, without affecting epidermal development. In neonatal epidermis, Jarid2 deficiency reduces H3K27 trimethylation, a chromatin repressive mark, in epidermal differentiation genes previously shown to be targets of the PRC2. However, in adult epidermis Jarid2 depletion does not affect interfollicular epidermal differentiation but results in delayed hair follicle (HF) cycling as a consequence of decreased proliferation of HF stem cells and their progeny. We conclude that Jarid2 is required for the scheduled proliferation of epidermal stem and progenitor cells necessary to maintain epidermal homeostasis.

  8. Signal integration by Ca2+ regulates intestinal stem cell activity

    PubMed Central

    Deng, Hansong; Gerencser, Akos A.; Jasper, Heinrich

    2015-01-01

    Summary Somatic stem cells (SCs) maintain tissue homeostasis by dynamically adjusting proliferation and differentiation in response to stress and metabolic cues. Here, we identify Ca2+ signaling as a central regulator of intestinal SC (ISC) activity in Drosophila. We find that dietary L-glutamate stimulates ISC division and gut growth. The metabotropic glutamate receptor (mGluR) is required in ISCs for this response and for an associated modulation of cytosolic Ca2+ oscillations that results in sustained high cytosolic Ca2+ concentrations. High cytosolic Ca2+ induces ISC proliferation by regulating Calcineurin and CREB - regulated transcriptional co-activator (CRTC). In response to a wide range of dietary and stress stimuli, ISCs reversibly transition between Ca2+ oscillation states that represent poised or activated modes of proliferation, respectively. We propose that the dynamic regulation of intracellular Ca2+ levels allows effective integration of diverse mitogenic signals in ISCs to tailor their proliferative activity to the needs of the tissue. PMID:26633624

  9. Enrichment of epidermal stem cells of rats by Vario magnetic activated cell sorting system.

    PubMed

    Chen, Wei; Zhang, Wei-wei; Shi, Chunying; Lian, Xiaohua; Yi, Shanghong; Yang, Tian

    2013-09-01

    Epidermal stem cells (ESCs) play an important role in skin homeostasis, wound repair, and tumorigensis which have great potential in scientific research and clinical application. So, the efficient isolation of these infrequent stem cells is very important for researchers to solve the problem of low purity and insufficient quantity of stem cells in vitro. The aim of this study was to investigate a method for the enrichment of ESCs by magnetic activated cell sorting system. The isolation strategy was CD71 depletion followed by α6-integrin positive selection. The percentage of α6(bri)CD71(dim) cells in isolated cells was 94.59%. Transmission electron microscopy results revealed that α6(bri) CD71(dim) cells exhibited some typical characteristics like progenitor cells, such as big nucleus, obvious nucleolus, large nuclear-cytoplasm ratio, and few organelles in cytoplasm. When cultured in vitro, the α6(bri)CD71(dim) cells had greater proliferating potential and higher colony-forming ability, and high levels of epidermal stem cell markers were expressed in our positive cells. ESCs have been successfully isolated from neonatal epidermis using Vario MACS and cultured in vitro. This isolation method is simple, fast, and inexpensive, providing an important tool for tissue engineering and cell transplantation studies.

  10. Macrophages Contribute to the Cyclic Activation of Adult Hair Follicle Stem Cells

    PubMed Central

    Castellana, Donatello; Paus, Ralf; Perez-Moreno, Mirna

    2014-01-01

    Skin epithelial stem cells operate within a complex signaling milieu that orchestrates their lifetime regenerative properties. The question of whether and how immune cells impact on these stem cells within their niche is not well understood. Here we show that skin-resident macrophages decrease in number because of apoptosis before the onset of epithelial hair follicle stem cell activation during the murine hair cycle. This process is linked to distinct gene expression, including Wnt transcription. Interestingly, by mimicking this event through the selective induction of macrophage apoptosis in early telogen, we identify a novel involvement of macrophages in stem cell activation in vivo. Importantly, the macrophage-specific pharmacological inhibition of Wnt production delays hair follicle growth. Thus, perifollicular macrophages contribute to the activation of skin epithelial stem cells as a novel, additional cue that regulates their regenerative activity. This finding may have translational implications for skin repair, inflammatory skin diseases and cancer. PMID:25536657

  11. Regulation of Breast Cancer Stem Cell Activity by Signalling Through the Notch4 Receptor

    PubMed Central

    Harrison, Hannah; Farnie, Gillian; Howell, Sacha J; Rock, Rebecca E; Stylianou, Spyros; Brennan, Keith R; Bundred, Nigel J; Clarke, Robert B

    2012-01-01

    The Notch receptor signalling pathway plays an important role in breast development, regulation of stem cells and differentiation of luminal progenitor cells. The pathway also plays a significant role in breast cancer development and progression. However, which of the Notch receptors that regulate breast cancer stem cells is unknown. We assessed stem cell activity in breast cancer cell lines and nine primary human tumour samples. In vitro and in vivo breast cancer stem cell activity was enriched using selection of anoikis resistant cells or cells expressing the membrane phenotype ESA+/CD44+/CD24low. We compared the activation of Notch receptors in the breast cancer stem cell-enriched population to luminally differentiated cells and studied the effects of pathway inhibition, both in vitro and in vivo. We find that Notch4 signalling activity is 8-fold higher in the breast cancer stem cell-enriched cells compared to the differentiated cells while Notch1 activation is 4-fold lower in breast cancer stem cells. Furthermore, pharmacological or genetic Notch inhibition markedly reduced breast cancer stem cell activity in vitro, and significantly reduced tumour formation in vivo. Importantly, cells with Notch4 knock-down using specific shRNA formed fewer mammosphere colonies than Notch1 knock-down cells. In vivo Notch1 knock-down, like pharmacological inhibition, reduced the number and size of tumours but Notch4 knock-down suppressed tumour initiation completely. Our findings indicate that Notch4-targeted therapies will be more effective than targeting Notch1 in suppressing breast cancer recurrence initiated by breast cancer stem cells. PMID:20068161

  12. Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation.

    PubMed

    Bruno, Stefania; Grange, Cristina; Tapparo, Marta; Pasquino, Chiara; Romagnoli, Renato; Dametto, Ennia; Amoroso, Antonio; Tetta, Ciro; Camussi, Giovanni

    2016-01-01

    Human liver stem cells (HLSCs) are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs), and dendritic cells (DCs) in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2) and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs), HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response. PMID:27127520

  13. Isolation of Mammalian Oogonial Stem Cells by Antibody-Based Fluorescence-Activated Cell Sorting.

    PubMed

    Navaroli, Deanna M; Tilly, Jonathan L; Woods, Dori C

    2016-01-01

    The ability to isolate and subsequently culture mitotically active female germ cells from adult ovaries, referred to as either oogonial stem cells (OSCs) or adult female germline stem cells (aFGSCs), has provided a robust system to study female germ cell development under multiple experimental conditions, and in many species. Flow cytometry or fluorescence-activated cell sorting (FACS) is an integral part of many isolation and characterization protocols. Here, we provide methodological details for antibody-based flow cytometric isolation of OSCs using antibodies specific for external epitopes of the proteins Ddx4 or Ifitm3, alone or in combination with the use of fluorescent reporter mice. Beginning with sample preparation, we provide point-by-point instructions to guide researchers on how to isolate OSCs using flow cytometry. PMID:27557587

  14. Immune suppressor factor confers stromal cell line with enhanced supporting activity for hematopoietic stem cells

    SciTech Connect

    Nakajima, Hideaki . E-mail: hnakajim@ims.u-tokyo.ac.jp; Shibata, Fumi; Fukuchi, Yumi; Goto-Koshino, Yuko; Ito, Miyuki; Urano, Atsushi; Nakahata, Tatsutoshi; Aburatani, Hiroyuki; Kitamura, Toshio

    2006-02-03

    Immune suppressor factor (ISF) is a subunit of the vacuolar ATPase proton pump. We earlier identified a short form of ISF (ShIF) as a stroma-derived factor that supports cytokine-independent growth of mutant Ba/F3 cells. Here, we report that ISF/ShIF supports self-renewal and expansion of primary hematopoietic stem cells (HSCs). Co-culture of murine bone marrow cells with a stromal cell line overexpressing ISF or ShIF (MS10/ISF or MS10/ShIF) not only enhanced their colony-forming activity and the numbers of long-term culture initiating cells, but also maintained the competitive repopulating activity of HSC. This stem cell supporting activity depended on the proton-transfer function of ISF/ShIF. Gene expression analysis of ISF/ShIF-transfected cell lines revealed down-regulation of secreted frizzled-related protein-1 and tissue inhibitor of metalloproteinase-3, and the restoration of their expressions in MS10/ISF cells partially reversed its enhanced LTC-IC supporting activity to a normal level. These results suggest that ISF/ShIF confers stromal cells with enhanced supporting activities for HSCs by modulating Wnt-activity and the extracellular matrix.

  15. Precise control of plant stem cell activity through parallel regulatory inputs.

    PubMed

    Bennett, Tom; van den Toorn, Albert; Willemsen, Viola; Scheres, Ben

    2014-11-01

    The regulation of columella stem cell activity in the Arabidopsis root cap by a nearby organizing centre, the quiescent centre, has been a key example of the stem cell niche paradigm in plants. Here, we investigate interactions between transcription factors that have been shown to regulate columella stem cells using a simple quantification method for stem cell activity in the root cap. Genetic and expression analyses reveal that the RETINOBLASTOMA-RELATED protein, the FEZ and SOMBRERO NAC-domain transcription factors, the ARF10 and ARF16 auxin response factors and the quiescent centre-expressed WOX5 homeodomain protein each provide independent inputs to regulate the number of columella stem cells. Given the tight control of columella development, we found that these inputs act in a surprisingly parallel manner. Nevertheless, important points of interaction exist; for example, we demonstrate the repression of SMB activity by non-autonomous action of WOX5. Our results suggest that the developmental progression of columella stem cells may be quantitatively regulated by several more broadly acting transcription factors rather than by a single intrinsic stem cell factor, which raises questions about the special nature of the stem cell state in plants.

  16. Dependence of stem cell fate in Arabidopsis on a feedback loop regulated by CLV3 activity.

    PubMed

    Brand, U; Fletcher, J C; Hobe, M; Meyerowitz, E M; Simon, R

    2000-07-28

    The fate of stem cells in plant meristems is governed by directional signaling systems that are regulated by negative feedback. In Arabidopsis thaliana, the CLAVATA (CLV) genes encode the essential components of a negative, stem cell-restricting pathway. We used transgenic plants overexpressing CLV3 to show that meristem cell accumulation and fate depends directly on the level of CLV3 activity and that CLV3 signaling occurs exclusively through a CLV1/CLV2 receptor kinase complex. We also demonstrate that the CLV pathway acts by repressing the activity of the transcription factor WUSCHEL, an element of the positive, stem cell-promoting pathway. PMID:10915624

  17. Foxi3 Deficiency Compromises Hair Follicle Stem Cell Specification and Activation.

    PubMed

    Shirokova, Vera; Biggs, Leah C; Jussila, Maria; Ohyama, Takahiro; Groves, Andrew K; Mikkola, Marja L

    2016-07-01

    The hair follicle is an ideal system to study stem cell specification and homeostasis due to its well characterized morphogenesis and stereotypic cycles of stem cell activation upon each hair cycle to produce a new hair shaft. The adult hair follicle stem cell niche consists of two distinct populations, the bulge and the more activation-prone secondary hair germ (HG). Hair follicle stem cells are set aside during early stages of morphogenesis. This process is known to depend on the Sox9 transcription factor, but otherwise the establishment of the hair follicle stem cell niche is poorly understood. Here, we show that that mutation of Foxi3, a Forkhead family transcription factor mutated in several hairless dog breeds, compromises stem cell specification. Further, loss of Foxi3 impedes hair follicle downgrowth and progression of the hair cycle. Genome-wide profiling revealed a number of downstream effectors of Foxi3 including transcription factors with a recognized function in hair follicle stem cells such as Lhx2, Runx1, and Nfatc1, suggesting that the Foxi3 mutant phenotype results from simultaneous downregulation of several stem cell signature genes. We show that Foxi3 displays a highly dynamic expression pattern during hair morphogenesis and cycling, and identify Foxi3 as a novel secondary HG marker. Absence of Foxi3 results in poor hair regeneration upon hair plucking, and a sparse fur phenotype in unperturbed mice that exacerbates with age, caused by impaired secondary HG activation leading to progressive depletion of stem cells. Thus, Foxi3 regulates multiple aspects of hair follicle development and homeostasis. Stem Cells 2016;34:1896-1908.

  18. Single-cell telomere-length quantification couples telomere length to meristem activity and stem cell development in Arabidopsis.

    PubMed

    González-García, Mary-Paz; Pavelescu, Irina; Canela, Andrés; Sevillano, Xavier; Leehy, Katherine A; Nelson, Andrew D L; Ibañes, Marta; Shippen, Dorothy E; Blasco, Maria A; Caño-Delgado, Ana I

    2015-05-12

    Telomeres are specialized nucleoprotein caps that protect chromosome ends assuring cell division. Single-cell telomere quantification in animals established a critical role for telomerase in stem cells, yet, in plants, telomere-length quantification has been reported only at the organ level. Here, a quantitative analysis of telomere length of single cells in Arabidopsis root apex uncovered a heterogeneous telomere-length distribution of different cell lineages showing the longest telomeres at the stem cells. The defects in meristem and stem cell renewal observed in tert mutants demonstrate that telomere lengthening by TERT sets a replicative limit in the root meristem. Conversely, the long telomeres of the columella cells and the premature stem cell differentiation plt1,2 mutants suggest that differentiation can prevent telomere erosion. Overall, our results indicate that telomere dynamics are coupled to meristem activity and continuous growth, disclosing a critical association between telomere length, stem cell function, and the extended lifespan of plants.

  19. Activation of the methylation cycle in cells reprogrammed into a stem cell-like state

    PubMed Central

    Bosch-Barrera, Joaquim; Alarcón, Tomás; Joven, Jorge; Menendez, Javier A.

    2015-01-01

    Generation of induced pluripotent stem (iPS) cells and cancer biogenesis share similar metabolic switches. Most studies have focused on how the establishment of a cancer-like glycolytic phenotype is necessary for the optimal routing of somatic cells for achieving stemness. However, relatively little effort has been dedicated towards elucidating how one-carbon (1C) metabolism is retuned during acquisition of stem cell identity. Here we used ultra-high pressure liquid chromatography coupled to an electrospray ionization source and a triple-quadrupole mass spectrometer [UHPLC-ESI-QqQ-MS/MS] to quantitatively examine the methionine/folate bi-cyclic 1C metabolome during nuclear reprogramming of somatic cells into iPS cells. iPS cells optimize the synthesis of the universal methyl donor S-adenosylmethionine (SAM), apparently augment the ability of the redox balance regulator NADPH in SAM biosynthesis, and greatly increase their methylation potential by triggering a high SAM:S-adenosylhomocysteine (SAH) ratio. Activation of the methylation cycle in iPS cells efficiently prevents the elevation of homocysteine (Hcy), which could alter global DNA methylation and induce mitochondrial toxicity, oxidative stress and inflammation. In this regard, the methyl donor choline is also strikingly accumulated in iPS cells, suggesting perhaps an overactive intersection of the de novo synthesis of choline with the methionine-Hcy cycle. Activation of methylogenesis and maintenance of an optimal SAM:Hcy ratio might represent an essential function of 1C metabolism to provide a labile pool of methyl groups and NADPH-dependent redox products required for successfully establishing and maintaining an embryonic-like DNA methylation imprint in stem cell states. PMID:26909364

  20. CTNNB1 Signaling in Sertoli Cells Downregulates Spermatogonial Stem Cell Activity via WNT4

    PubMed Central

    Boyer, Alexandre; Yeh, Jonathan R.; Zhang, Xiangfan; Paquet, Marilène; Gaudin, Aurore; Nagano, Makoto C.; Boerboom, Derek

    2012-01-01

    Constitutive activation of the WNT signaling effector CTNNB1 (β-catenin) in the Sertoli cells of the Ctnnb1tm1Mmt/+;Amhr2tm3(cre)Bhr/+ mouse model results in progressive germ cell loss and sterility. In this study, we sought to determine if this phenotype could be due to a loss of spermatogonial stem cell (SSC) activity. Reciprocal SSC transplants between Ctnnb1tm1Mmt/+;Amhr2tm3(cre)Bhr/+ and wild-type mice showed that SSC activity is lost in Ctnnb1tm1Mmt/+;Amhr2tm3(cre)Bhr/+ testes over time, whereas the mutant testes could not support colonization by wild-type SSCs. Microarray analyses performed on cultured Sertoli cells showed that CTNNB1 induces the expression of genes associated with the female sex determination pathway, which was also found to occur in Ctnnb1tm1Mmt/+;Amhr2tm3(cre)Bhr/+ testes. One CTNNB1 target gene encoded the secreted signaling molecule WNT4. We therefore tested the effects of WNT4 on SSC-enriched germ cell cultures, and found that WNT4 induced cell death and reduced SSC activity without affecting cell cycle. Conversely, conditional inactivation of Wnt4 in the Ctnnb1tm1Mmt/+;Amhr2tm3(cre)Bhr/+ model rescued spermatogenesis and male fertility, indicating that WNT4 is the major effector downstream of CTNNB1 responsible for germ cell loss. Furthermore, WNT4 was found to signal via the CTNNB1 pathway in Sertoli cells, suggesting a self-reinforcing positive feedback loop. Collectively, these data indicate for the first time that ectopic activation of a signaling cascade in the stem cell niche depletes SSC activity through a paracrine factor. These findings may provide insight into the pathogenesis of male infertility, as well as embryonic gonadal development. PMID:22253774

  1. Cisplatin selects for stem-like cells in osteosarcoma by activating Notch signaling

    PubMed Central

    Yang, Jian; Gao, Tian; Simões, Bruno M.; Eyre, Rachel; Guo, Weichun; Clarke, Robert B.

    2016-01-01

    Notch signaling regulates normal stem cells and is also thought to regulate cancer stem cells (CSCs). Recent data indicate that Notch signaling plays a role in the development and progression of osteosarcoma, however the regulation of Notch in chemo-resistant stem-like cells has not yet been fully elucidated. In this study we generated cisplatin-resistant osteosarcoma cells by treating them with sub-lethal dose of cisplatin, sufficient to induce DNA damage responses. Cisplatin-resistant osteosarcoma cells exhibited lower proliferation, enhanced spheroid formation and more mesenchymal characteristics than cisplatin-sensitive cells, were enriched for Stro-1+/CD117+ cells and showed increased expression of stem cell-related genes. A similar effect was observed in vivo, and in addition in vivo tumorigenicity was enhanced during serial transplantation. Using several publicly available datasets, we identified that Notch expression was closely associated with osteosarcoma stem cells and chemotherapy resistance. We confirmed that cisplatin-induced enrichment of osteosarcoma stem cells was mediated through Notch signaling in vitro, and immunohistochemistry showed that cleaved Notch1 (NICD1) positive cells were significantly increased in a relapsed xenograft which had received cisplatin treatment. Furthermore, pretreatment with a γ-secretase inhibitor (GSI) to prevent Notch signalling inhibited cisplatin-enriched osteosarcoma stem cell activity in vitro, including Stro-1+/CD117+ double positive cells and spheroid formation capacity. The Notch inhibitor DAPT also prevented tumor recurrence in resistant xenograft tumors. Overall, our results show that cisplatin induces the enrichment of osteosarcoma stem-like cells through Notch signaling, and targeted inactivation of Notch may be useful for the elimination of CSCs and overcoming drug resistance. PMID:27102300

  2. Human embryonic stem cell-derived neuronal cells form spontaneously active neuronal networks in vitro.

    PubMed

    Heikkilä, Teemu J; Ylä-Outinen, Laura; Tanskanen, Jarno M A; Lappalainen, Riikka S; Skottman, Heli; Suuronen, Riitta; Mikkonen, Jarno E; Hyttinen, Jari A K; Narkilahti, Susanna

    2009-07-01

    The production of functional human embryonic stem cell (hESC)-derived neuronal cells is critical for the application of hESCs in treating neurodegenerative disorders. To study the potential functionality of hESC-derived neurons, we cultured and monitored the development of hESC-derived neuronal networks on microelectrode arrays. Immunocytochemical studies revealed that these networks were positive for the neuronal marker proteins beta-tubulin(III) and microtubule-associated protein 2 (MAP-2). The hESC-derived neuronal networks were spontaneously active and exhibited a multitude of electrical impulse firing patterns. Synchronous bursts of electrical activity similar to those reported for hippocampal neurons and rodent embryonic stem cell-derived neuronal networks were recorded from the differentiated cultures until up to 4 months. The dependence of the observed neuronal network activity on sodium ion channels was examined using tetrodotoxin (TTX). Antagonists for the glutamate receptors NMDA [D(-)-2-amino-5-phosphonopentanoic acid] and AMPA/kainate [6-cyano-7-nitroquinoxaline-2,3-dione], and for GABAA receptors [(-)-bicuculline methiodide] modulated the spontaneous electrical activity, indicating that pharmacologically susceptible neuronal networks with functional synapses had been generated. The findings indicate that hESC-derived neuronal cells can generate spontaneously active networks with synchronous communication in vitro, and are therefore suitable for use in developmental and drug screening studies, as well as for regenerative medicine.

  3. Stem cell activation by light guides plant organogenesis.

    PubMed

    Yoshida, Saiko; Mandel, Therese; Kuhlemeier, Cris

    2011-07-01

    Leaves originate from stem cells located at the shoot apical meristem. The meristem is shielded from the environment by older leaves, and leaf initiation is considered to be an autonomous process that does not depend on environmental cues. Here we show that light acts as a morphogenic signal that controls leaf initiation and stabilizes leaf positioning. Leaf initiation in tomato shoot apices ceases in the dark but resumes in the light, an effect that is mediated through the plant hormone cytokinin. Dark treatment also affects the subcellular localization of the auxin transporter PIN1 and the concomitant formation of auxin maxima. We propose that cytokinin is required for meristem propagation, and that auxin redirects cytokinin-inducible meristem growth toward organ formation. In contrast to common wisdom over the last 150 years, the light environment controls the initiation of lateral organs by regulating two key hormones: auxin and cytokinin.

  4. Chemotherapy induces stemness in osteosarcoma cells through activation of Wnt/β-catenin signaling.

    PubMed

    Martins-Neves, Sara R; Paiva-Oliveira, Daniela I; Wijers-Koster, Pauline M; Abrunhosa, Antero J; Fontes-Ribeiro, Carlos; Bovée, Judith V M G; Cleton-Jansen, Anne-Marie; Gomes, Célia M F

    2016-01-28

    Development of resistance represents a major drawback in osteosarcoma treatment, despite improvements in overall survival. Treatment failure and tumor progression have been attributed to pre-existing drug-resistant clones commonly assigned to a cancer stem-like phenotype. Evidence suggests that non stem-like cells, when submitted to certain microenvironmental stimuli, can acquire a stemness phenotype thereby strengthening their capacity to handle with stressful conditions. Here, using osteosarcoma cell lines and a mouse xenograft model, we show that exposure to conventional chemotherapeutics induces a phenotypic cell transition toward a stem-like phenotype. This associates with activation of Wnt/β-catenin signaling, up-regulation of pluripotency factors and detoxification systems (ABC transporters and Aldefluor activity) that ultimately leads to chemotherapy failure. Wnt/β-catenin inhibition combined with doxorubicin, in the MNNG-HOS cells, prevented the up-regulation of factors linked to transition into a stem-like state and can be envisaged as a way to overcome adaptive resistance. Finally, the analysis of the public R2 database, containing microarray data information from diverse osteosarcoma tissues, revealed a correlation between expression of stemness markers and a worse response to chemotherapy, which provides evidence for drug-induced phenotypic stem cell state transitions in osteosarcoma. PMID:26577806

  5. Cyclin E-dependent protein kinase activity regulates niche retention of Drosophila ovarian follicle stem cells

    PubMed Central

    Wang, Zhu A.; Kalderon, Daniel

    2009-01-01

    Whether stem cells have unique cell cycle machineries and how they integrate with niche interactions remains largely unknown. We identified a hypomorphic cyclin E allele WX that strongly impairs the maintenance of follicle stem cells (FSCs) in the Drosophila ovary but does not reduce follicle cell proliferation or germline stem cell maintenance. CycEWX protein can still bind to the cyclin-dependent kinase catalytic subunit Cdk2, but forms complexes with reduced protein kinase activity measured in vitro. By creating additional CycE variants with different degrees of kinase dysfunction and expressing these and CycEWX at different levels, we found that higher CycE-Cdk2 kinase activity is required for FSC maintenance than to support follicle cell proliferation. Surprisingly, cycEWX FSCs were lost from their niches rather than arresting proliferation. Furthermore, FSC function was substantially restored by expressing either excess DE-cadherin or excess E2F1/DP, the transcription factor normally activated by CycE-Cdk2 phosphorylation of retinoblastoma proteins. These results suggest that FSC maintenance through niche adhesion is regulated by inputs that normally control S phase entry, possibly as a quality control mechanism to ensure adequate stem cell proliferation. We speculate that a positive connection between central regulators of the cell cycle and niche retention may be a common feature of highly proliferative stem cells. PMID:19966222

  6. Analysis of Germline Stem Cell Differentiation Following Loss of GLP-1 Notch Activity in Caenorhabditis elegans

    PubMed Central

    Fox, Paul M.; Schedl, Tim

    2015-01-01

    Stem cells generate the differentiated progeny cells of adult tissues. Stem cells in the Caenorhabditis elegans hermaphrodite germline are maintained within a proliferative zone of ∼230 cells, ∼20 cell diameters in length, through GLP-1 Notch signaling. The distal tip cell caps the germline and supplies GLP-1-activating ligand, and the distal-most germ cells that occupy this niche are likely self-renewing stem cells with active GLP-1 signaling. As germ cells are displaced from the niche, GLP-1 activity likely decreases, yet mitotically cycling germ cells are found throughout the proliferative zone prior to overt meiotic differentiation. Following loss of GLP-1 activity, it remains unclear whether stem cells undergo transit-amplifying (TA) divisions or more directly enter meiosis. To distinguish between these possibilities we employed a temperature-sensitive (ts) glp-1 mutant to manipulate GLP-1 activity. We characterized proliferative zone dynamics in glp-1(ts) mutants at permissive temperature and then analyzed the kinetics of meiotic entry of proliferative zone cells after loss of GLP-1. We found that entry of proliferative zone cells into meiosis following loss of GLP-1 activity is largely synchronous and independent of their distal-proximal position. Furthermore, the majority of cells complete only a single mitotic division before entering meiosis, independent of their distal-proximal position. We conclude that germ cells do not undergo TA divisions following loss of GLP-1 activity. We present a model for the dynamics of the proliferative zone that utilizes cell cycle rate and proliferative zone size and output and incorporates the more direct meiotic differentiation of germ cells following loss of GLP-1 activity. PMID:26158953

  7. Analysis of Germline Stem Cell Differentiation Following Loss of GLP-1 Notch Activity in Caenorhabditis elegans.

    PubMed

    Fox, Paul M; Schedl, Tim

    2015-09-01

    Stem cells generate the differentiated progeny cells of adult tissues. Stem cells in the Caenorhabditis elegans hermaphrodite germline are maintained within a proliferative zone of ∼230 cells, ∼20 cell diameters in length, through GLP-1 Notch signaling. The distal tip cell caps the germline and supplies GLP-1-activating ligand, and the distal-most germ cells that occupy this niche are likely self-renewing stem cells with active GLP-1 signaling. As germ cells are displaced from the niche, GLP-1 activity likely decreases, yet mitotically cycling germ cells are found throughout the proliferative zone prior to overt meiotic differentiation. Following loss of GLP-1 activity, it remains unclear whether stem cells undergo transit-amplifying (TA) divisions or more directly enter meiosis. To distinguish between these possibilities we employed a temperature-sensitive (ts) glp-1 mutant to manipulate GLP-1 activity. We characterized proliferative zone dynamics in glp-1(ts) mutants at permissive temperature and then analyzed the kinetics of meiotic entry of proliferative zone cells after loss of GLP-1. We found that entry of proliferative zone cells into meiosis following loss of GLP-1 activity is largely synchronous and independent of their distal-proximal position. Furthermore, the majority of cells complete only a single mitotic division before entering meiosis, independent of their distal-proximal position. We conclude that germ cells do not undergo TA divisions following loss of GLP-1 activity. We present a model for the dynamics of the proliferative zone that utilizes cell cycle rate and proliferative zone size and output and incorporates the more direct meiotic differentiation of germ cells following loss of GLP-1 activity.

  8. Activation of Type II Cells into Regenerative Stem Cell Antigen-1+ Cells during Alveolar Repair

    PubMed Central

    Kumar, Varsha Suresh; Zhang, Wei; Rehman, Jalees; Malik, Asrar B.

    2015-01-01

    The alveolar epithelium is composed of two cell types: type I cells comprise 95% of the gas exchange surface area, whereas type II cells secrete surfactant, while retaining the ability to convert into type I cells to induce alveolar repair. Using lineage-tracing analyses in the mouse model of Pseudomonas aeruginosa–induced lung injury, we identified a population of stem cell antigen (Sca)-1–expressing type II cells with progenitor cell properties that mediate alveolar repair. These cells were shown to be distinct from previously reported Sca-1–expressing bronchioalveolar stem cells. Microarray and Wnt reporter studies showed that surfactant protein (Sp)-C+Sca-1+ cells expressed Wnt signaling pathway genes, and inhibiting Wnt/β-catenin signaling prevented the regenerative function of Sp-C+Sca-1+ cells in vitro. Thus, P. aeruginosa–mediated lung injury induces the generation of a Sca-1+ subset of type II cells. The progenitor phenotype of the Sp-C+Sca-1+ cells that mediates alveolar epithelial repair might involve Wnt signaling. PMID:25474582

  9. Stem Cell Sciences plc.

    PubMed

    Daniels, Sebnem

    2006-09-01

    Stem Cell Sciences' core objective is to develop safe and effective stem cell-based therapies for currently incurable diseases. In order to achieve this goal, Stem Cell Sciences recognizes the need for multiple technologies and a globally integrated stem cell initiative. The key challenges for the successful application of stem cells in the clinic is the need for a reproducible supply of pure, fully characterized stem cells that have been grown in suitable conditions for use in the clinic.

  10. Epigenetic regulator Lid maintains germline stem cells through regulating JAK-STAT signaling pathway activity

    PubMed Central

    Tarayrah, Lama; Li, Yuping; Gan, Qiang; Chen, Xin

    2015-01-01

    ABSTRACT Signaling pathways and epigenetic mechanisms have both been shown to play essential roles in regulating stem cell activity. While the role of either mechanism in this regulation is well established in multiple stem cell lineages, how the two mechanisms interact to regulate stem cell activity is not as well understood. Here we report that in the Drosophila testis, an H3K4me3-specific histone demethylase encoded by little imaginal discs (lid) maintains germline stem cell (GSC) mitotic index and prevents GSC premature differentiation. Lid is required in germ cells for proper expression of the Stat92E transcription factor, the downstream effector of the Janus kinase signal transducer and activator of transcription (JAK-STAT) signaling pathway. Our findings support a germ cell autonomous role for the JAK-STAT pathway in maintaining GSCs and place Lid as an upstream regulator of this pathway. Our study provides new insights into the biological functions of a histone demethylase in vivo and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities. PMID:26490676

  11. Dehydrated human amnion/chorion membrane regulates stem cell activity in vitro

    PubMed Central

    Massee, Michelle; Chinn, Kathryn; Lei, Jennifer; Lim, Jeremy J.; Young, Conan S.

    2015-01-01

    Abstract Human‐derived placental tissues have been shown in randomized clinical trials to be effective for healing chronic wounds, and have also demonstrated the ability to recruit stem cells to the wound site in vitro and in vivo. In this study, PURION® Processed dehydrated human amnion/chorion membrane allografts (dHACM, EpiFix®, MiMedx Group, Marietta, GA) were evaluated for their ability to alter stem cell activity in vitro. Human bone marrow mesenchymal stem cells (BM‐MSCs), adipose derived stem cells (ADSCs), and hematopoietic stem cells (HSCs) were treated with soluble extracts of dHACM tissue, and were evaluated for cellular proliferation, migration, and cytokine secretion. Stem cells were analyzed for cell number by DNA assay after 24 h, closure of an acellular zone using microscopy over 3 days, and soluble cytokine production in the medium of treated stem cells was analyzed after 3 days using a multiplex ELISA array. Treatment with soluble extracts of dHACM tissue stimulated BM‐MSCs, ADSCs, and HSCs to proliferate with a significant increase in cell number after 24 h. dHACM treatment accelerated closure of an acellular zone by ADSCs and BM‐MSCs after 3 days, compared to basal medium. BM‐MSCs, ADSCs, and HSCs also modulated endogenous production of a number of various soluble signals, including regulators of inflammation, mitogenesis, and wound healing. dHACM treatment promoted increased proliferation and migration of ADSCs, BM‐MSCs, and HSCs, along with modulation of secreted proteins from those cells. Therefore, dHACM may impact wound healing by amplifying host stem cell populations and modulating their responses in treated wound tissues. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1495–1503, 2016. PMID:26175122

  12. Dehydrated human amnion/chorion membrane regulates stem cell activity in vitro.

    PubMed

    Massee, Michelle; Chinn, Kathryn; Lei, Jennifer; Lim, Jeremy J; Young, Conan S; Koob, Thomas J

    2016-10-01

    Human-derived placental tissues have been shown in randomized clinical trials to be effective for healing chronic wounds, and have also demonstrated the ability to recruit stem cells to the wound site in vitro and in vivo. In this study, PURION(®) Processed dehydrated human amnion/chorion membrane allografts (dHACM, EpiFix(®) , MiMedx Group, Marietta, GA) were evaluated for their ability to alter stem cell activity in vitro. Human bone marrow mesenchymal stem cells (BM-MSCs), adipose derived stem cells (ADSCs), and hematopoietic stem cells (HSCs) were treated with soluble extracts of dHACM tissue, and were evaluated for cellular proliferation, migration, and cytokine secretion. Stem cells were analyzed for cell number by DNA assay after 24 h, closure of an acellular zone using microscopy over 3 days, and soluble cytokine production in the medium of treated stem cells was analyzed after 3 days using a multiplex ELISA array. Treatment with soluble extracts of dHACM tissue stimulated BM-MSCs, ADSCs, and HSCs to proliferate with a significant increase in cell number after 24 h. dHACM treatment accelerated closure of an acellular zone by ADSCs and BM-MSCs after 3 days, compared to basal medium. BM-MSCs, ADSCs, and HSCs also modulated endogenous production of a number of various soluble signals, including regulators of inflammation, mitogenesis, and wound healing. dHACM treatment promoted increased proliferation and migration of ADSCs, BM-MSCs, and HSCs, along with modulation of secreted proteins from those cells. Therefore, dHACM may impact wound healing by amplifying host stem cell populations and modulating their responses in treated wound tissues. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1495-1503, 2016.

  13. Porcine Adipose-Derived Mesenchymal Stem Cells Retain Their Stem Cell Characteristics and Cell Activities While Enhancing the Expression of Liver-Specific Genes after Acute Liver Failure.

    PubMed

    Hu, Chenxia; Zhou, Ning; Li, Jianzhou; Shi, Ding; Cao, Hongcui; Li, Jun; Li, Lanjuan

    2016-01-05

    Acute liver failure (ALF) is a kind of complicated syndrome. Furthermore, adipose-derived mesenchymal stem cells (ADMSCs) can serve as a useful cell resource for autotransplantation due to their abundance and micro-invasive accessability. However, it is unknown how ALF will influence the characteristics of ADMSCs and whether ADMSCs from patients suffering from end-stage liver diseases are potential candidates for autotransplantation. This study was designed to compare various properties of ALF-derived ADMSCs with normal ADMSCs in pig models, with regard to their cellular morphology, cell proliferative ability, cell apoptosis, expression of surface antigens, mitochondrial and lysosomal activities, multilineage potency, and expression of liver-specific genes. Our results showed that ALF does not influence the stem cell characteristics and cell activities of ADMSCs. Intriguingly, the expression levels of several liver-specific genes in ALF-derived ADMSCs are higher than in normal ADMSCs. In conclusion, our findings indicate that the stem cell characteristics and cell activities of ADMSCs were not altered by ALF and these cells can serve as a new source for regenerative medicine.

  14. Porcine Adipose-Derived Mesenchymal Stem Cells Retain Their Stem Cell Characteristics and Cell Activities While Enhancing the Expression of Liver-Specific Genes after Acute Liver Failure

    PubMed Central

    Hu, Chenxia; Zhou, Ning; Li, Jianzhou; Shi, Ding; Cao, Hongcui; Li, Jun; Li, Lanjuan

    2016-01-01

    Acute liver failure (ALF) is a kind of complicated syndrome. Furthermore, adipose-derived mesenchymal stem cells (ADMSCs) can serve as a useful cell resource for autotransplantation due to their abundance and micro-invasive accessability. However, it is unknown how ALF will influence the characteristics of ADMSCs and whether ADMSCs from patients suffering from end-stage liver diseases are potential candidates for autotransplantation. This study was designed to compare various properties of ALF-derived ADMSCs with normal ADMSCs in pig models, with regard to their cellular morphology, cell proliferative ability, cell apoptosis, expression of surface antigens, mitochondrial and lysosomal activities, multilineage potency, and expression of liver-specific genes. Our results showed that ALF does not influence the stem cell characteristics and cell activities of ADMSCs. Intriguingly, the expression levels of several liver-specific genes in ALF-derived ADMSCs are higher than in normal ADMSCs. In conclusion, our findings indicate that the stem cell characteristics and cell activities of ADMSCs were not altered by ALF and these cells can serve as a new source for regenerative medicine. PMID:26742034

  15. β-Catenin activation regulates tissue growth non-cell autonomously in the hair stem cell niche.

    PubMed

    Deschene, Elizabeth R; Myung, Peggy; Rompolas, Panteleimon; Zito, Giovanni; Sun, Thomas Yang; Taketo, Makoto M; Saotome, Ichiko; Greco, Valentina

    2014-03-21

    Wnt/β-catenin signaling is critical for tissue regeneration. However, it is unclear how β-catenin controls stem cell behaviors to coordinate organized growth. Using live imaging, we show that activation of β-catenin specifically within mouse hair follicle stem cells generates new hair growth through oriented cell divisions and cellular displacement. β-Catenin activation is sufficient to induce hair growth independently of mesenchymal dermal papilla niche signals normally required for hair regeneration. Wild-type cells are co-opted into new hair growths by β-catenin mutant cells, which non-cell autonomously activate Wnt signaling within the neighboring wild-type cells via Wnt ligands. This study demonstrates a mechanism by which Wnt/β-catenin signaling controls stem cell-dependent tissue growth non-cell autonomously and advances our understanding of the mechanisms that drive coordinated regeneration.

  16. Metastable primordial germ cell-like state induced from mouse embryonic stem cells by Akt activation

    SciTech Connect

    Yamano, Noriko; Kimura, Tohru; Watanabe-Kushima, Shoko; Shinohara, Takashi; Nakano, Toru

    2010-02-12

    Specification to primordial germ cells (PGCs) is mediated by mesoderm-induction signals during gastrulation. We found that Akt activation during in vitro mesodermal differentiation of embryonic stem cells (ESCs) generated self-renewing spheres with differentiation states between those of ESCs and PGCs. Essential regulators for PGC specification and their downstream germ cell-specific genes were expressed in the spheres, indicating that the sphere cells had commenced differentiation to the germ lineage. However, the spheres did not proceed to spermatogenesis after transplantation into testes. Sphere cell transfer to the original feeder-free ESC cultures resulted in chaotic differentiation. In contrast, when the spheres were cultured on mouse embryonic fibroblasts or in the presence of ERK-cascade and GSK3 inhibitors, reversion to the ESC-like state was observed. These results indicate that Akt signaling promotes a novel metastable and pluripotent state that is intermediate to those of ESCs and PGCs.

  17. Multi-Parameter Fluorescence-Activated Cell Sorting and Analysis of Stem and Progenitor Cells in Myeloid Malignancies

    PubMed Central

    Will, Britta; Steidl, Ulrich

    2010-01-01

    Owing to the discovery that rare leukemia-initiating cells (or leukemia stem cells, LSC) give origin to and propagate a hierarchical cellular organization of variably differentiated leukemic blasts, the analysis of precisely defined stem and progenitor cells has increasingly gained importance. Emergence of multi-parameter high-speed fluorescence-activated cell sorting (FACS) for the subfractionation of hematopoietic progenitor cells has allowed research on the biology of the cell-of-origin for LSCs and of LSCs as potential (or essential) therapeutic targets that may escape chemotherapy and consequently contribute to disease relapse. This review introduces the current state-of-the-art methods for the fractionation of hematopoietic stem and progenitor cells, with particular focus on myeloid malignancies. As many aspects of human normal and malignant hematopoiesis are frequently modeled in animal studies, we also provide an overview of hematopoietic stem and progenitor cell purification methods that are commonly utilized for research in murine models of disease. PMID:21112038

  18. The activation of directional stem cell motility by green light-emitting diode irradiation.

    PubMed

    Ong, Wei-Kee; Chen, How-Foo; Tsai, Cheng-Ting; Fu, Yun-Ju; Wong, Yi-Shan; Yen, Da-Jen; Chang, Tzu-Hao; Huang, Hsien-Da; Lee, Oscar Kuang-Sheng; Chien, Shu; Ho, Jennifer Hui-Chun

    2013-03-01

    Light-emitting diode (LED) irradiation is potentially a photostimulator to manipulate cell behavior by opsin-triggered phototransduction and thermal energy supply in living cells. Directional stem cell motility is critical for the efficiency and specificity of stem cells in tissue repair. We explored that green LED (530 nm) irradiation directed the human orbital fat stem cells (OFSCs) to migrate away from the LED light source through activation of extracellular signal-regulated kinases (ERK)/MAP kinase/p38 signaling pathway. ERK inhibitor selectively abrogated light-driven OFSC migration. Phosphorylation of these kinases as well as green LED irradiation-induced cell migration was facilitated by increasing adenosine triphosphate (ATP) production in OFSCs after green LED exposure, and which was thermal stress-independent mechanism. OFSCs, which are multi-potent mesenchymal stem cells isolated from human orbital fat tissue, constitutionally express three opsins, i.e. retinal pigment epithelium-derived rhodopsin homolog (RRH), encephalopsin (OPN3) and short-wave-sensitive opsin 1 (OPN1SW). However, only two non-visual opsins, i.e. RRH and OPN3, served as photoreceptors response to green LED irradiation-induced OFSC migration. In conclusion, stem cells are sensitive to green LED irradiation-induced directional cell migration through activation of ERK signaling pathway via a wavelength-dependent phototransduction.

  19. Local activation of cardiac stem cells for post-myocardial infarction cardiac repair.

    PubMed

    Wen, Zhuzhi; Mai, Zun; Zhang, Haifeng; Chen, Yangxin; Geng, Dengfeng; Zhou, Shuxian; Wang, Jingfeng

    2012-11-01

    The prognosis of patients with myocardial infarction (MI) and resultant chronic heart failure remains extremely poor despite continuous advancements in optimal medical therapy and interventional procedures. Animal experiments and clinical trials using adult stem cell therapy following MI have shown a global improvement of myocardial function. The emergence of stem cell transplantation approaches has recently represented promising alternatives to stimulate myocardial regeneration. Regarding their tissue-specific properties, cardiac stem cells (CSCs) residing within the heart have advantages over other stem cell types to be the best cell source for cell transplantation. However, time-consuming and costly procedures to expanse cells prior to cell transplantation and the reliability of cell culture and expansion may both be major obstacles in the clinical application of CSC-based transplantation therapy after MI. The recognition that the adult heart possesses endogenous CSCs that can regenerate cardiomyocytes and vascular cells has raised the unique therapeutic strategy to reconstitute dead myocardium via activating these cells post-MI. Several strategies, such as growth factors, mircoRNAs and drugs, may be implemented to potentiate endogenous CSCs to repair infarcted heart without cell transplantation. Most molecular and cellular mechanism involved in the process of CSC-based endogenous regeneration after MI is far from understanding. This article reviews current knowledge opening up the possibilities of cardiac repair through CSCs activation in situ in the setting of MI.

  20. Stem cell-based gene therapy activated using magnetic hyperthermia to enhance the treatment of cancer.

    PubMed

    Yin, Perry T; Shah, Shreyas; Pasquale, Nicholas J; Garbuzenko, Olga B; Minko, Tamara; Lee, Ki-Bum

    2016-03-01

    Stem cell-based gene therapies, wherein stem cells are genetically engineered to express therapeutic molecules, have shown tremendous potential for cancer applications owing to their innate ability to home to tumors. However, traditional stem cell-based gene therapies are hampered by our current inability to control when the therapeutic genes are actually turned on, thereby resulting in detrimental side effects. Here, we report the novel application of magnetic core-shell nanoparticles for the dual purpose of delivering and activating a heat-inducible gene vector that encodes TNF-related apoptosis-inducing ligand (TRAIL) in adipose-derived mesenchymal stem cells (AD-MSCs). By combining the tumor tropism of the AD-MSCs with the spatiotemporal MCNP-based delivery and activation of TRAIL expression, this platform provides an attractive means with which to enhance our control over the activation of stem cell-based gene therapies. In particular, we found that these engineered AD-MSCs retained their innate ability to proliferate, differentiate, and, most importantly, home to tumors, making them ideal cellular carriers. Moreover, exposure of the engineered AD-MSCS to mild magnetic hyperthermia resulted in the selective expression of TRAIL from the engineered AD-MSCs and, as a result, induced significant ovarian cancer cell death in vitro and in vivo.

  1. Plant Stem Cells.

    PubMed

    Greb, Thomas; Lohmann, Jan U

    2016-09-12

    Among the trending topics in the life sciences, stem cells have received a fair share of attention in the public debate - mostly in connection with their potential for biomedical application and therapies. While the promise of organ regeneration and the end of cancer have captured our imagination, it has gone almost unnoticed that plant stem cells represent the ultimate origin of much of the food we eat, the oxygen we breathe, as well the fuels we burn. Thus, plant stem cells may be ranked among the most important cells for human well-being. Research by many labs in the last decades has uncovered a set of independent stem cell systems that fulfill the specialized needs of plant development and growth in four dimensions. Surprisingly, the cellular and molecular design of these systems is remarkably similar, even across diverse species. In some long-lived plants, such as trees, plant stem cells remain active over hundreds or even thousands of years, revealing the exquisite precision in the underlying control of proliferation, self-renewal and differentiation. In this minireview, we introduce the basic features of the three major plant stem cell systems building on these facts, highlight their modular design at the level of cellular layout and regulatory underpinnings and briefly compare them with their animal counterparts. PMID:27623267

  2. Sox2 expression in breast tumours and activation in breast cancer stem cells.

    PubMed

    Leis, O; Eguiara, A; Lopez-Arribillaga, E; Alberdi, M J; Hernandez-Garcia, S; Elorriaga, K; Pandiella, A; Rezola, R; Martin, A G

    2012-03-15

    The cancer stem cell (CSC) model does not imply that tumours are generated from transformed tissue stem cells. The target of transformation could be a tissue stem cell, a progenitor cell, or a differentiated cell that acquires self-renewal ability. The observation that induced pluripotency reprogramming and cancer are related has lead to the speculation that CSCs may arise through a reprogramming-like mechanism. Expression of pluripotency genes (Oct4, Nanog and Sox2) was tested in breast tumours by immunohistochemistry and it was found that Sox2 is expressed in early stage breast tumours. However, expression of Oct4 or Nanog was not found. Mammosphere formation in culture was used to reveal stem cell properties, where expression of Sox2, but not Oct4 or Nanog, was induced. Over-expression of Sox2 increased mammosphere formation, effect dependent on continuous Sox2 expression; furthermore, Sox2 knockdown prevented mammosphere formation and delayed tumour formation in xenograft tumour initiation models. Induction of Sox2 expression was achieved through activation of the distal enhancer of Sox2 promoter upon sphere formation, the same element that controls Sox2 transcription in pluripotent stem cells. These findings suggest that reactivation of Sox2 represents an early step in breast tumour initiation, explaining tumour heterogeneity by placing the tumour-initiating event in any cell along the axis of mammary differentiation.

  3. Comparative analysis of telomere length, telomerase and reverse transcriptase activity in human dental stem cells.

    PubMed

    Jeon, Byeong-Gyun; Kang, Eun-Ju; Kumar, B Mohana; Maeng, Geun-Ho; Ock, Sun-A; Kwack, Dae-Oh; Park, Bong-Wook; Rho, Gyu-Jin

    2011-01-01

    Stem cells from dental tissues have been isolated and established for tooth regenerative applications. However, basic characterization on their biological properties still needs to be investigated before employing them for effective clinical trials. In this study, we compared the telomere length, relative telomerase activity (RTA), and relative reverse transcriptase activity (RRA) as well as the surface antigen profile and mesenchymal differentiation ability in human dental papilla stem cells (DPaSCs), dental pulp stem cells (DPuSCs), and dental follicle stem cells (DFSCs) with mesenchymal stem cells (MSCs) derived from bone marrow. Dental stem cells (DSCs) were strongly positive for cell surface markers, such as CD44 and CD90. However, slightly lower expression of CD105 was observed in DPaSCs and DPuSCs compared to DFSCs and MSCs. Following specific induction, DPaSCs, DFSCs, and MSCs were successfully differentiated into adipocytes and osteocytes. However, DPuSCS, in particular, were able to differentiate into adipocytes but failed to induce into osteogenic differentiation. Further, all DSCs, MSCs, and MRC-5 fibroblasts as control were investigated for telomere length by nonradioactive chemiluminescent assay, RTA by relative-quantitative telomerase repeat amplification protocol (RQ-TRAP), and RRA by PCR-based assay. Mean telomere lengths in DPaSCs, DPuSCs, DFSCs, and MSCs was ∼11 kb, and the values did not differ significantly (p < 0.05) among the cells analyzed. RTA levels in DPaSCs were significantly (p < 0.05) higher than in MSCs, DPuSCs, DFSCs, and MRC-5 fibroblasts and among DSCs, DFSCs showed a significantly (p < 0.05) lower RTA. Moreover, RRA levels were significantly (p < 0.05) higher in DPaSCs, DPuSCs, and MSCs than in DFSCs. Based on these observations, we conclude that among DSCs, DPaSCs possessed ideal characteristics on telomere length, telomerase activity and reverse transcriptase (RTase) activity, and may serve as suitable alternative candidates

  4. Correlation between proliferative activity and cellular thickness of human mesenchymal stem cells

    SciTech Connect

    Katsube, Yoshihiro; Hirose, Motohiro Nakamura, Chikashi; Ohgushi, Hajime

    2008-04-04

    A cell's shape is known to be related to its proliferative activity. In particular, large and flat mammalian adult stem cells seem to show slow proliferation, however using quantitative analysis to prove the phenomenon is difficult. We measured the proliferation and cellular thickness of human mesenchymal stem cells (MSCs) by atomic force microscopy and found that MSCs with high proliferative activity were thick while those with low proliferative activity were thin, even though these MSCs were early passage cells. Further, low proliferative MSCs contained many senescence-associated {beta}-galactosidase positive cells together with high senescence-associated gene expression. These findings suggest that the measurement of cellular thickness is useful for estimating the proliferative activity of human MSCs and is expected to be a practical tool for MSC applications in regenerative medicine.

  5. Melanocytes, melanocyte stem cells, and melanoma stem cells.

    PubMed

    Lang, Deborah; Mascarenhas, Joseph B; Shea, Christopher R

    2013-01-01

    Melanocyte stem cells differ greatly from melanoma stem cells; the former provide pigmented cells during normal tissue homeostasis and repair, and the latter play an active role in a lethal form of cancer. These 2 cell types share several features and can be studied by similar methods. Aspects held in common by both melanocyte stem cells and melanoma stem cells include their expression of shared biochemical markers, a system of similar molecular signals necessary for their maintenance, and a requirement for an ideal niche microenvironment for providing these factors. This review provides a perspective of both these cell types and discusses potential models of stem cell growth and propagation. Recent findings provide a strong foundation for the development of new therapeutics directed at isolating and manipulating melanocyte stem cells for tissue engineering or at targeting and eradicating melanoma specifically, while sparing nontumor cells.

  6. Stem cells supporting other stem cells

    PubMed Central

    Leatherman, Judith

    2013-01-01

    Adult stem cell therapies are increasingly prevalent for the treatment of damaged or diseased tissues, but most of the improvements observed to date are attributed to the ability of stem cells to produce paracrine factors that have a trophic effect on existing tissue cells, improving their functional capacity. It is now clear that this ability to produce trophic factors is a normal and necessary function for some stem cell populations. In vivo adult stem cells are thought to self-renew due to local signals from the microenvironment where they live, the niche. Several niches have now been identified which harbor multiple stem cell populations. In three of these niches – the Drosophila testis, the bulge of the mammalian hair follicle, and the mammalian bone marrow – one type of stem cell has been found to produce factors that contribute to the maintenance of a second stem cell population in the shared niche. In this review, I will examine the architecture of these three niches and discuss the molecular signals involved. Together, these examples establish a new paradigm for stem cell behavior, that stem cells can promote the maintenance of other stem cells. PMID:24348512

  7. Stem Cell Emergence and Hemopoietic Activity Are Incompatible in Mouse Intraembryonic Sites

    PubMed Central

    Godin, Isabelle; Garcia-Porrero, Juan Antonio; Dieterlen-Lièvre, Françoise; Cumano, Ana

    1999-01-01

    In the mouse embryo, the generation of candidate progenitors for long-lasting hemopoiesis has been reported in the paraaortic splanchnopleura (P-Sp)/aorta-gonad-mesonephros (AGM) region. Here, we address the following question: can the P-Sp/AGM environment support hemopoietic differentiation as well as generate stem cells, and, conversely, are other sites where hemopoietic differentiation occurs capable of generating stem cells? Although P-Sp/AGM generates de novo hemopoietic stem cells between 9.5 and 12.5 days post coitus (dpc), we show here that it does not support hemopoietic differentiation. Among mesoderm-derived sites, spleen and omentum were shown to be colonized by exogenous cells in the same fashion as the fetal liver. Cells colonizing the spleen were multipotent and pursued their evolution to committed progenitors in this organ. In contrast, the omentum, which was colonized by lymphoid-committed progenitors that did not expand, cannot be considered as a hemopoietic organ. From these data, stem cell generation appears incompatible with hemopoietic activity. At the peak of hemopoietic progenitor production in the P-Sp/AGM, between 10.5 and 11.5 dpc, multipotent cells were found at the exceptional frequency of 1 out of 12 total cells and 1 out of 4 AA4.1+ cells. Thus, progenitors within this region constitute a pool of undifferentiated hemopoietic cells readily accessible for characterization. PMID:10429669

  8. Cell culture density affects the proliferation activity of human adipose tissue stem cells.

    PubMed

    Kim, Dae Seong; Lee, Myoung Woo; Ko, Young Jong; Chun, Yong Hoon; Kim, Hyung Joon; Sung, Ki Woong; Koo, Hong Hoe; Yoo, Keon Hee

    2016-01-01

    In this study, we investigated the effect of cell density on the proliferation activity of human mesenchymal stem cells (MSCs) derived from adipose tissue (AT-MSCs) over time in culture. Passage #4 (P4) and #12 (P12) AT-MSCs from two donors were plated at a density of 200 (culture condition 1, CC1) or 5000 (culture condition 2, CC2) cells cm(-2) . After 7 days of incubation, P4 and P12 AT-MSCs cultured in CC1 were thin and spindle-shaped, whereas those cultured in CC2 had extensive cell-to-cell contacts and an expanded cell volume. In addition, P4 and P12 AT-MSCs in CC1 divided more than three times, while those in CC2 divided less than once on average. Flow cytometric analysis using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester dye showed that the fluorescence intensity of AT-MSCs was lower in CC1 than in CC2. Furthermore, expression of proliferation-associated genes, such as CDC45L, CDC20A and KIF20A, in P4 AT-MSCs was higher in CC1 than in CC2, and this difference was also observed in P12 AT-MSCs. These data demonstrated that cell culture density affects the proliferation activity of MSCs, suggesting that it is feasible to design a strategy to prepare suitable MSCs using specific culture conditions.

  9. Transcriptional link between blood and bone: the stem cell leukemia gene and its +19 stem cell enhancer are active in bone cells.

    PubMed

    Pimanda, John E; Silberstein, Lev; Dominici, Massimo; Dekel, Benjamin; Bowen, Mark; Oldham, Scott; Kallianpur, Asha; Brandt, Stephen J; Tannahill, David; Göttgens, Berthold; Green, Anthony R

    2006-04-01

    Blood and vascular cells are generated during early embryogenesis from a common precursor, the hemangioblast. The stem cell leukemia gene (SCL/tal 1) encodes a basic helix-loop-helix transcription factor that is essential for the normal development of blood progenitors and blood vessels. We have previously characterized a panel of SCL enhancers including the +19 element, which directs expression to hematopoietic stem cells and endothelium. Here we demonstrate that SCL is expressed in bone primordia during embryonic development and in adult osteoblasts. Despite consistent expression in cells of the osteogenic lineage, SCL protein is not required for bone specification of embryonic stem cells. In transgenic mice, the SCL +19 core enhancer directed reporter gene expression to vascular smooth muscle and bone in addition to blood and endothelium. A 644-bp fragment containing the SCL +19 core enhancer was active in both blood and bone cell lines and was bound in vivo by a common array of Ets and GATA transcription factors. Taken together with the recent observation that a common progenitor can give rise to blood and bone cells, our results suggest that the SCL +19 enhancer targets a mesodermal progenitor capable of generating hematopoietic, vascular, and osteoblastic progeny.

  10. FOXA1 expression affects the proliferation activity of luminal breast cancer stem cell populations.

    PubMed

    Tachi, Kana; Shiraishi, Akira; Bando, Hiroko; Yamashita, Toshiharu; Tsuboi, Ikki; Kato, Toshiki; Hara, Hisato; Ohneda, Osamu

    2016-03-01

    The expression of estrogen receptor is the key in most breast cancers (BC) and binding of estrogen receptor to the genome correlates to Forkhead protein (FOXA1) expression. We herein assessed the correlation between the cancer stem cell (CSC) population and FOXA1 expression in luminal BC. We established luminal BC cells derived from metastatic pleural effusion and analyzed the potency of CSC and related factors with established luminal BC cell lines. We also confirmed that mammosphere cultures have an increased aldehyde dehydrogenase-positive population, which is one of the CSC markers, compared with adherent culture cells. Using a quantitative PCR analysis, we found that mammosphere forming cells showed a higher expression of FOXA1 and stemness-related genes compared with adherent culture cells. Furthermore, the growth activity and colony-forming activity of 4-hydroxytamoxifen-treated BC cells were inhibited in a mammosphere assay. Interestingly, 4-hydroxytamoxifen-resistant cells had significantly increased FOXA1 gene expression levels. Finally, we established short hairpin RNA of FOXA1 (shFOXA1) MCF-7 cells and investigated the relationship between self-renewal potential and FOXA1 expression. As a result, we found no significant difference in the number of mammospheres but decreased colony formation in shFOXA1 MCF-7 cells compared with control. These results suggest that the expression of FOXA1 appears to be involved in the proliferation of immature BC cells rather than the induction of stemness-related genes and self-renewal potency of CSCs.

  11. Ciliary neurotrophic factor promotes the activation of corneal epithelial stem/progenitor cells and accelerates corneal epithelial wound healing.

    PubMed

    Zhou, Qingjun; Chen, Peng; Di, Guohu; Zhang, Yangyang; Wang, Yao; Qi, Xia; Duan, Haoyun; Xie, Lixin

    2015-05-01

    Ciliary neurotrophic factor (CNTF), a well-known neuroprotective cytokine, has been found to play an important role in neurogenesis and functional regulations of neural stem cells. As one of the most innervated tissue, however, the role of CNTF in cornea epithelium remains unclear. This study was to explore the roles and mechanisms of CNTF in the activation of corneal epithelial stem/progenitor cells and wound healing of both normal and diabetic mouse corneal epithelium. In mice subjecting to mechanical removal of corneal epithelium, the corneal epithelial stem/progenitor cell activation and wound healing were promoted by exogenous CNTF application, while delayed by CNTF neutralizing antibody. In cultured corneal epithelial stem/progenitor cells, CNTF enhanced the colony-forming efficiency, stimulated the mitogenic proliferation, and upregulated the expression levels of corneal epithelial stem/progenitor cell-associated transcription factors. Furthermore, the promotion of CNTF on the corneal epithelial stem/progenitor cell activation and wound healing was mediated by the activation of STAT3. Moreover, in diabetic mice, the content of CNTF in corneal epithelium decreased significantly when compared with that of normal mice, and the supplement of CNTF promoted the diabetic corneal epithelial wound healing, accompanied with the advanced activation of corneal epithelial stem/progenitor cells and the regeneration of corneal nerve fibers. Thus, the capability of expanding corneal epithelial stem/progenitor cells and promoting corneal epithelial wound healing and nerve regeneration indicates the potential application of CNTF in ameliorating limbal stem cell deficiency and treating diabetic keratopathy.

  12. NF-Kβ Activation in U266 Cells on Mesenchymal Stem Cells

    PubMed Central

    Zahedi, Sara; Shamsasenjan, Karim; Movassaghpour, Aliakbar; Akbarzadehlaleh, Parvin

    2016-01-01

    Purpose: Mesenchymal Stem Cells (MSCs) are one of the essential members of Bone Marrow (BM) microenvironment and the cells affect normal and malignant cells in BM milieu. One of the most important hematological malignancies is Multiple Myeloma (MM). Numerous studies reported various effects of MSCs on myeloma cells. MSCs initiate various signaling pathways in myeloma cells, particularly NF-kβ. NF-kβ signaling pathway plays pivotal role in the survival, proliferation and resistance of myeloma cells to the anticancer drugs, therefore this pathway can be said to be a vital target for cancer therapy. This study examined the relationship between U266 cells and MSCs. Methods: U266 cells were cultured with Umbilical Cord Blood derived-MSCs (UCB-MSCs) and Conditioned Medium (C.M). Effect of UCB-MSCs and C.M on proliferation rate and CD54 expression of U266 cells were examined with MTT assay and Flowcytometry respectively. Furthermore, expression of CXCL1, PECAM-1, JUNB, CCL2, CD44, CCL4, IL-6, and IL-8 were analyzed by Real Time-PCR (RT-PCR). Moreover, status of p65 protein in NF-kβ pathway assessed by western blotting. Results: Our findings confirm that UCB-MSCs support U266 cells proliferation and they increase CD54 expression. In addition, we demonstrate that UCB-MSCs alter the expression of CCL4, IL-6, IL-8, CXCL1 and the levels of phosphorylated p65 in U266 cells. Conclusion: Our study provides a novel sight to the role of MSCs in the activation of NF-kβ signaling pathway. So, NF-kβ signaling pathway will be targeted in future therapies against MM. PMID:27766226

  13. Angiogenic activity mediates bone repair from human pluripotent stem cell-derived osteogenic cells

    PubMed Central

    Zou, Li; Chen, Qingshan; Quanbeck, Zachary; Bechtold, Joan E.; Kaufman, Dan S.

    2016-01-01

    Human pluripotent stem cells provide a standardized resource for bone repair. However, criteria to determine which exogenous cells best heal orthopedic injuries remain poorly defined. We evaluated osteogenic progenitor cells derived from both human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs). Phenotypic and genotypic analyses demonstrated that these hESCs/hiPSCs are similar in their osteogenic differentiation efficiency and they generate osteogenic cells comparable to osteogenic cells derived from mesenchymal stromal cells (BM-MSCs). However, expression of angiogenic factors, such as vascular endothelial growth factor and basic fibroblast growth factor in these osteogenic progenitor cells are markedly different, suggesting distinct pro-angiogenic potential of these stem cell derivatives. Studies to repair a femur non-union fracture demonstrate only osteogenic progenitor cells with higher pro-angiogenic potential significantly enhance bone repair in vivo. Together, these studies highlight a key role of pro-angiogenic potential of transplanted osteogenic cells for effective cell-mediated bone repair. PMID:26980556

  14. Anticarcinogenic activity of polyphenolic extracts from grape stems against breast, colon, renal and thyroid cancer cells.

    PubMed

    Sahpazidou, Despina; Geromichalos, George D; Stagos, Dimitrios; Apostolou, Anna; Haroutounian, Serkos A; Tsatsakis, Aristidis M; Tzanakakis, George N; Hayes, A Wallace; Kouretas, Dimitrios

    2014-10-15

    A major part of the wineries' wastes is composed of grape stems which are discarded mainly in open fields and cause environmental problems due mainly to their high polyphenolic content. The grape stem extracts' use as a source of high added value polyphenols presents great interest because this combines a profitable venture with environmental protection close to wine-producing zones. In the present study, at first, the Total Polyphenolic Content (TPC) and the polyphenolic composition of grape stem extracts from four different Greek Vitis vinifera varieties were determined by HPLC methods. Afterwards, the grape stem extracts were examined for their ability to inhibit growth of colon (HT29), breast (MCF-7 and MDA-MB-23), renal (786-0 and Caki-1) and thyroid (K1) cancer cells. The cancer cells were exposed to the extracts for 72 h and the effects on cell growth were evaluated using the SRB assay. The results indicated that all extracts inhibited cell proliferation, with IC₅₀ values of 121-230 μg/ml (MCF-7), 121-184 μg/ml (MDA-MD-23), 175-309 μg/ml (HT29), 159-314 μg/ml (K1), 180-225 μg/ml (786-0) and 134->400 μg/ml (Caki-1). This is the first study presenting the inhibitory activity of grape stem extracts against growth of colon, breast, renal and thyroid cancer cells.

  15. Rapid fusion between mesenchymal stem cells and cardiomyocytes yields electrically active, non-contractile hybrid cells

    PubMed Central

    Shadrin, Ilya Y.; Yoon, Woohyun; Li, Liqing; Shepherd, Neal; Bursac, Nenad

    2015-01-01

    Cardiac cell therapies involving bone marrow-derived human mesenchymal stem cells (hMSCs) have shown promising results, although their mechanisms of action are still poorly understood. Here, we investigated direct interactions between hMSCs and cardiomyocytes in vitro. Using a genetic Ca2+ indicator gCaMP3 to efficiently label hMSCs in co-cultures with neonatal rat ventricular myocytes (NRVMs), we determined that 25–40% of hMSCs (from 4 independent donors) acquired periodic Ca2+ transients and cardiac markers through spontaneous fusion with NRVMs. Sharp electrode and voltage-clamp recordings in fused cells showed action potential properties and Ca2+ current amplitudes in between those of non-fused hMSCs and NRVMs. Time-lapse video-microscopy revealed the first direct evidence of active fusion between hMSCs and NRVMs within several hours of co-culture. Application of blebbistatin, nifedipine or verapamil caused complete and reversible inhibition of fusion, suggesting potential roles for actomyosin bridging and Ca2+ channels in the fusion process. Immunostaining for Cx43, Ki67, and sarcomeric α-actinin showed that fused cells remain strongly coupled to surrounding NRVMs, but downregulate sarcomeric structures over time, acquiring a non-proliferative and non-contractile phenotype. Overall, these results describe the phenotype and mechanisms of hybrid cell formation via fusion of hMSCs and cardiomyocytes with potential implications for cardiac cell therapy. PMID:26159124

  16. Maintenance of Stem Cell Niche Integrity by a Novel Activator of Integrin Signaling

    PubMed Central

    Lee, Joo Yeun; Chang, Karen T.

    2016-01-01

    Stem cells depend critically on the surrounding microenvironment, or niche, for their maintenance and self-renewal. While much is known about how the niche regulates stem cell self-renewal and differentiation, mechanisms for how the niche is maintained over time are not well understood. At the apical tip of the Drosophila testes, germline stem cells (GSCs) and somatic stem cells share a common niche formed by hub cells. Here we demonstrate that a novel protein named Shriveled (Shv) is necessary for the maintenance of hub/niche integrity. Depletion of Shv protein results in age-dependent deterioration of the hub structure and loss of GSCs, whereas upregulation of Shv preserves the niche during aging. We find Shv is a secreted protein that modulates DE-cadherin levels through extracellular activation of integrin signaling. Our work identifies Shv as a novel activator of integrin signaling and suggests a new integration model in which crosstalk between integrin and DE-cadherin in niche cells promote their own preservation by maintaining the niche architecture. PMID:27191715

  17. CDK6 as a key regulator of hematopoietic and leukemic stem cell activation.

    PubMed

    Scheicher, Ruth; Hoelbl-Kovacic, Andrea; Bellutti, Florian; Tigan, Anca-Sarmiza; Prchal-Murphy, Michaela; Heller, Gerwin; Schneckenleithner, Christine; Salazar-Roa, María; Zöchbauer-Müller, Sabine; Zuber, Johannes; Malumbres, Marcos; Kollmann, Karoline; Sexl, Veronika

    2015-01-01

    The cyclin-dependent kinase 6 (CDK6) and CDK4 have redundant functions in regulating cell-cycle progression. We describe a novel role for CDK6 in hematopoietic and leukemic stem cells (hematopoietic stem cells [HSCs] and leukemic stem cells [LSCs]) that exceeds its function as a cell-cycle regulator. Although hematopoiesis appears normal under steady-state conditions, Cdk6(-/-) HSCs do not efficiently repopulate upon competitive transplantation, and Cdk6-deficient mice are significantly more susceptible to 5-fluorouracil treatment. We find that activation of HSCs requires CDK6, which interferes with the transcription of key regulators, including Egr1. Transcriptional profiling of HSCs is consistent with the central role of Egr1. The impaired repopulation capacity extends to BCR-ABL(p210+) LSCs. Transplantation with BCR-ABL(p210+)-infected bone marrow from Cdk6(-/-) mice fails to induce disease, although recipient mice do harbor LSCs. Egr1 knock-down in Cdk6(-/-) BCR-ABL(p210+) LSKs significantly enhances the potential to form colonies, underlining the importance of the CDK6-Egr1 axis. Our findings define CDK6 as an important regulator of stem cell activation and an essential component of a transcriptional complex that suppresses Egr1 in HSCs and LSCs.

  18. CDK6 as a key regulator of hematopoietic and leukemic stem cell activation

    PubMed Central

    Scheicher, Ruth; Hoelbl-Kovacic, Andrea; Bellutti, Florian; Tigan, Anca-Sarmiza; Prchal-Murphy, Michaela; Heller, Gerwin; Schneckenleithner, Christine; Salazar-Roa, María; Zöchbauer-Müller, Sabine; Zuber, Johannes; Malumbres, Marcos; Kollmann, Karoline

    2015-01-01

    The cyclin-dependent kinase 6 (CDK6) and CDK4 have redundant functions in regulating cell-cycle progression. We describe a novel role for CDK6 in hematopoietic and leukemic stem cells (hematopoietic stem cells [HSCs] and leukemic stem cells [LSCs]) that exceeds its function as a cell-cycle regulator. Although hematopoiesis appears normal under steady-state conditions, Cdk6−/− HSCs do not efficiently repopulate upon competitive transplantation, and Cdk6-deficient mice are significantly more susceptible to 5-fluorouracil treatment. We find that activation of HSCs requires CDK6, which interferes with the transcription of key regulators, including Egr1. Transcriptional profiling of HSCs is consistent with the central role of Egr1. The impaired repopulation capacity extends to BCR-ABLp210+ LSCs. Transplantation with BCR-ABLp210+–infected bone marrow from Cdk6−/− mice fails to induce disease, although recipient mice do harbor LSCs. Egr1 knock-down in Cdk6−/− BCR-ABLp210+ LSKs significantly enhances the potential to form colonies, underlining the importance of the CDK6-Egr1 axis. Our findings define CDK6 as an important regulator of stem cell activation and an essential component of a transcriptional complex that suppresses Egr1 in HSCs and LSCs. PMID:25342715

  19. Wnt ligands regulate Tkv expression to constrain Dpp activity in the Drosophila ovarian stem cell niche

    PubMed Central

    Luo, Lichao; Wang, Huashan; Fan, Chao; Liu, Sen

    2015-01-01

    Stem cell self-renewal versus differentiation is regulated by the niche, which provides localized molecules that favor self-renewal. In the Drosophila melanogaster female germline stem cell (GSC) niche, Decapentaplegic (Dpp), a fly transforming growth factor β molecule and well-established long-range morphogen, acts over one cell diameter to maintain the GSCs. Here, we show that Thickveins (Tkv; a type I receptor of Dpp) is highly expressed in stromal cells next to Dpp-producing cells and functions to remove excess Dpp outside the niche, thereby spatially restricting its activity. Interestingly, Tkv expression in these stromal cells is regulated by multiple Wnt ligands that are produced by the niche. Our data demonstrate a self-restraining mechanism by which the Drosophila ovarian GSC niche acts to define its own boundary. PMID:26008746

  20. Prospective identification of tumorigenic osteosarcoma cancer stem cells in OS99-1 cells based on high aldehyde dehydrogenase activity.

    PubMed

    Wang, Lin; Park, Paul; Zhang, Huina; La Marca, Frank; Lin, Chia-Ying

    2011-01-15

    High aldehyde dehydrogenase (ALDH) activity has recently been used to identify tumorigenic cell fractions in many cancer types. Herein we hypothesized that a subpopulation of cells with cancer stem cells (CSCs) properties could be identified in established human osteosarcoma cell lines based on high ALDH activity. We previously showed that a subpopulation of cells with high ALDH activity were present in 4 selected human osteosarcoma cell lines, of which a significantly higher ALDH activity was present in the OS99-1 cell line that was originally derived from a highly aggressive primary human osteosarcoma. Using a xenograft model in which OS99-1 cells were grown in NOD/SCID mice, we identified a highly tumorigenic subpopulation of osteosarcoma cells based on their high ALDH activity. Cells with high ALDH activity (ALDH(br) cells) from the OS99-1 xenografts were much less frequent, averaging 3% of the entire tumor population, compared to those isolated directly from the OS99-1 cell line. ALDH(br) cells from the xenograft were enriched with greater tumorigenicity compared to their counterparts with low ALDH activity (ALDH(lo) cells), generating new tumors with as few as 100 cells in vivo. The highly tumorigenic ALDH(br) cells illustrated the stem cell characteristics of self-renewal, the ability to produce differentiated progeny and increased expression of stem cell marker genes OCT3/4A, Nanog and Sox-2. The isolation of osteosarcoma CSCs by their high ALDH activity may provide new insight into the study of osteosarcoma-initiating cells and may potentially have therapeutic implications for human osteosarcoma.

  1. Endothelial cells promote neural stem cell proliferation and differentiation associated with VEGF activated Notch and Pten signaling.

    PubMed

    Sun, Jinqiao; Zhou, Wenhao; Ma, Duan; Yang, Yi

    2010-09-01

    To investigate whether and how endothelial cells affect neurogenesis, we established a system to co-culture endothelial cells and brain slices of neonatal rat and observed how subventricular zone cells differentiate in the presence of endothelial cells. In the presence of endothelial cells, neural stem cells increased in number, as did differentiated neurons and glia. The augmentation of neurogenesis was reversed by diminishing vascular endothelial growth factor (VEGF) expression in endothelial cells with RNA interference (RNAi). Microarray analysis indicated that expression levels of 112 genes were significantly altered by co-culture and that expression of 81 of the 112 genes recovered to normal levels following RNAi of VEGF in endothelial cells. Pathway mapping showed an enrichment of genes in the Notch and Pten pathways. These data indicate that endothelial cells promote neural stem cell proliferation and differentiation associated with VEGF, possibly by activating the Notch and Pten pathways.

  2. PRL1 modulates root stem cell niche activity and meristem size through WOX5 and PLTs in Arabidopsis.

    PubMed

    Ji, Hongtao; Wang, Shuangfeng; Li, Kexue; Szakonyi, Dóra; Koncz, Csaba; Li, Xia

    2015-02-01

    The stem cell niche in the root meristem maintains pluripotent stem cells to ensure a constant supply of cells for root growth. Despite extensive progress, the molecular mechanisms through which root stem cell fates and stem cell niche activity are determined remain largely unknown. In Arabidopsis thaliana, the Pleiotropic Regulatory Locus 1 (PRL1) encodes a WD40-repeat protein subunit of the spliceosome-activating Nineteen Complex (NTC) that plays a role in multiple stress, hormone and developmental signaling pathways. Here, we show that PRL1 is involved in the control of root meristem size and root stem cell niche activity. PRL1 is strongly expressed in the root meristem and its loss of function mutation results in disorganization of the quiescent center (QC), premature stem cell differentiation, aberrant cell division, and reduced root meristem size. Our genetic studies indicate that PRL1 is required for confined expression of the homeodomain transcription factor WOX5 in the QC and acts upstream of the transcription factor PLETHORA (PLT) in modulating stem cell niche activity and root meristem size. These findings define a role for PRL1 as an important determinant of PLT signaling that modulates maintenance of the stem cell niche and root meristem size.

  3. Complete TCR-α gene locus control region activity in T cells derived in vitro from embryonic stem cells.

    PubMed

    Lahiji, Armin; Kucerová-Levisohn, Martina; Lovett, Jordana; Holmes, Roxanne; Zúñiga-Pflücker, Juan Carlos; Ortiz, Benjamin D

    2013-07-01

    Locus control regions (LCRs) are cis-acting gene regulatory elements with the unique, integration site-independent ability to transfer the characteristics of their locus-of-origin's gene expression pattern to a linked transgene in mice. LCR activities have been discovered in numerous T cell lineage-expressed gene loci. These elements can be adapted to the design of stem cell gene therapy vectors that direct robust therapeutic gene expression to the T cell progeny of engineered stem cells. Currently, transgenic mice provide the only experimental approach that wholly supports all the critical aspects of LCR activity. In this study, we report the manifestation of all key features of mouse TCR-α gene LCR function in T cells derived in vitro from mouse embryonic stem cells. High-level, copy number-related TCR-α LCR-linked reporter gene expression levels are cell type restricted in this system, and upregulated during the expected stage transition of T cell development. We also report that de novo introduction of TCR-α LCR-linked transgenes into existing T cell lines yields incomplete LCR activity. These data indicate that establishing full TCR-α LCR activity requires critical molecular events occurring prior to final T lineage determination. This study also validates a novel, tractable, and more rapid approach for the study of LCR activity in T cells, and its translation to therapeutic genetic engineering.

  4. Signal integration by Ca(2+) regulates intestinal stem-cell activity.

    PubMed

    Deng, Hansong; Gerencser, Akos A; Jasper, Heinrich

    2015-12-10

    Somatic stem cells maintain tissue homeostasis by dynamically adjusting proliferation and differentiation in response to stress and metabolic cues. Here we identify Ca(2+) signalling as a central regulator of intestinal stem cell (ISC) activity in Drosophila. We show that dietary L-glutamate stimulates ISC division and gut growth. The metabotropic glutamate receptor (mGluR) is required in ISCs for this response, and for an associated modulation of cytosolic Ca(2+) oscillations that results in sustained high cytosolic Ca(2+) concentrations. High cytosolic Ca(2+) concentrations induce ISC proliferation by regulating Calcineurin and CREB-regulated transcriptional co-activator (Crtc). In response to a wide range of dietary and stress stimuli, ISCs reversibly transition between Ca(2+) oscillation states that represent poised or activated modes of proliferation, respectively. We propose that the dynamic regulation of intracellular Ca(2+) levels allows effective integration of diverse mitogenic signals in ISCs to adapt their proliferative activity to the needs of the tissue.

  5. The use of covalently immobilized stem cell factor to selectively affect hematopoietic stem cell activity within a gelatin hydrogel.

    PubMed

    Mahadik, Bhushan P; Pedron Haba, Sara; Skertich, Luke J; Harley, Brendan A C

    2015-10-01

    Hematopoietic stem cells (HSCs) are a rare stem cell population found primarily in the bone marrow and responsible for the production of the body's full complement of blood and immune cells. Used clinically to treat a range of hematopoietic disorders, there is a significant need to identify approaches to selectively expand their numbers ex vivo. Here we describe a methacrylamide-functionalized gelatin (GelMA) hydrogel for in vitro culture of primary murine HSCs. Stem cell factor (SCF) is a critical biomolecular component of native HSC niches in vivo and is used in large dosages in cell culture media for HSC expansion in vitro. We report a photochemistry based approach to covalently immobilize SCF within GelMA hydrogels via acrylate-functionalized polyethylene glycol (PEG) tethers. PEG-functionalized SCF retains the native bioactivity of SCF but can be stably incorporated and retained within the GelMA hydrogel over 7 days. Freshly-isolated murine HSCs cultured in GelMA hydrogels containing covalently-immobilized SCF showed reduced proliferation and improved selectivity for maintaining primitive HSCs. Comparatively, soluble SCF within the GelMA hydrogel network induced increased proliferation of differentiating hematopoietic cells. We used a microfluidic templating approach to create GelMA hydrogels containing gradients of immobilized SCF that locally direct HSC response. Together, we report a biomaterial platform to examine the effect of the local presentation of soluble vs. matrix-immobilized biomolecular signals on HSC expansion and lineage specification. This approach may be a critical component of a biomaterial-based artificial bone marrow to provide the correct sequence of niche signals to grow HSCs in the laboratory.

  6. The use of covalently immobilized stem cell factor to selectively affect hematopoietic stem cell activity within a gelatin hydrogel

    PubMed Central

    Mahadik, B.P.; Haba, S. Pedron; Skertich, L.J.; Harley, B.A.C.

    2015-01-01

    Hematopoietic stem cells (HSCs) are a rare stem cell population found primarily in the bone marrow and responsible for the production of the body’s full complement of blood and immune cells. Used clinically to treat a range of hematopoietic disorders, there is a significant need to identify approaches to selectively expand their numbers ex vivo. Here we describe a methacrylamide-functionalized gelatin (GelMA) hydrogel for in vitro culture of primary murine HSCs. Stem cell factor (SCF) is a critical biomolecular component of native HSC niches in vivo and is used in large dosages in cell culture media for HSC expansion in vitro. We report a photochemistry based approach to covalently immobilize SCF within GelMA hydrogels via acrylate-functionalized polyethylene glycol (PEG) tethers. PEG-functionalized SCF retains the native bioactivity of SCF but can be stably incorporated and retained within the GelMA hydrogel over 7 days. Freshly-isolated murine HSCs cultured in GelMA hydrogels containing covalently-immobilized SCF showed reduced proliferation and improved selectivity for maintaining primitive HSCs. Comparatively, soluble SCF within the GelMA hydrogel network induced increased proliferation of differentiating hematopoietic cells. We used a microfluidic templating approach to create GelMA hydrogels containing gradients of immobilized SCF that locally direct HSC response. Together, we report a biomaterial platform to examine the effect of the local presentation of soluble vs. matrix-immobilized biomolecular signals on HSC expansion and lineage specification. This approach may be a critical component of a biomaterial-based artificial bone marrow to provide the correct sequence of niche signals to grow HSCs in the laboratory. PMID:26232879

  7. Boswellic acid activity against glioblastoma stem-like cells

    PubMed Central

    SCHNEIDER, HANNAH; WELLER, MICHAEL

    2016-01-01

    Boswellic acids (BAs) have long been considered as useful adjunct pharmacological agents for the treatment of patients with malignant brain tumors, notably glioblastoma. Two principal modes of action associated with BAs have been postulated: i) Anti-inflammatory properties, which are useful for containing edema formation, and ii) intrinsic antitumor cell properties, with a hitherto ill-defined mode of action. The present study assessed the effects of various BA derivatives on the viability and clonogenicity of a panel of nine long-term glioma cell lines and five glioma-initiating cell lines, studied cell cycle progression and the mode of cell death induction, and explored potential synergy with temozolomide (TMZ) or irradiation. BA induced the concentration-dependent loss of viability and clonogenicity that was independent of tumor protein 53 status and O6-methylguanine DNA methyltransferase expression. The treatment of glioma cells with BA resulted in cell death induction, prior to or upon S phase entry, and exhibited features of apoptotic cell death. Synergy with irradiation or TMZ was detected at certain concentrations; however, the inhibitory effects were mostly additive, and never antagonistic. While the intrinsic cytotoxic properties of BA at low micromolecular concentrations were confirmed and the potential synergy with irradiation and TMZ was identified, the proximate pharmacodynamic target of BA remains to be identified. PMID:27313764

  8. Targeting leukemia stem cells: which pathways drive self-renewal activity in T-cell acute lymphoblastic leukemia?

    PubMed Central

    Belmonte, M.; Hoofd, C.; Weng, A.P.; Giambra, V.

    2016-01-01

    T-Cell acute lymphoblastic leukemia (t-all) is a malignancy of white blood cells, characterized by an uncontrolled accumulation of T-cell progenitors. During leukemic progression, immature T cells grow abnormally and crowd into the bone marrow, preventing it from making normal blood cells and spilling out into the bloodstream. Recent studies suggest that only discrete cell populations that possess the ability to recreate the entire tumour might be responsible for the initiation and propagation of t-all. Those unique cells are commonly called “cancer stem cells” or, in the case of hematopoietic malignancies, “leukemia stem cells” (lscs). Like normal hematopoietic stem cells, lscs are thought to be capable of self-renewal, during which, by asymmetrical division, they give rise to an identical copy of themselves as well as to a daughter cell that is no longer capable of self-renewal activity and represents a more “differentiated” progeny. Here, we review the main pathways of self-renewal activity in lscs, focusing on their involvement in the maintenance and development of t-all. New stem cell–directed therapies and lsc-targeted agents are also discussed. PMID:26966402

  9. Promotion of haematopoietic activity in embryonic stem cells by the aorta-gonad-mesonephros microenvironment

    SciTech Connect

    Krassowska, Anna; Gordon-Keylock, Sabrina; Samuel, Kay; Gilchrist, Derek; Dzierzak, Elaine; Oostendorp, Robert; Forrester, Lesley M. . E-mail: l.forrester@ed.ac.uk; Ansell, John D.

    2006-11-01

    We investigated whether the in vitro differentiation of ES cells into haematopoietic progenitors could be enhanced by exposure to the aorta-gonadal-mesonephros (AGM) microenvironment that is involved in the generation of haematopoietic stem cells (HSC) during embryonic development. We established a co-culture system that combines the requirements for primary organ culture and differentiating ES cells and showed that exposure of differentiating ES cells to the primary AGM region results in a significant increase in the number of ES-derived haematopoietic progenitors. Co-culture of ES cells on the AM20-1B4 stromal cell line derived from the AGM region also increases haematopoietic activity. We conclude that factors promoting the haematopoietic activity of differentiating ES cells present in primary AGM explants are partially retained in the AM20.1B4 stromal cell line and that these factors are likely to be different to those required for adult HSC maintenance.

  10. Stem Cell Research.

    PubMed

    Trounson, Alan; Kolaja, Kyle; Petersen, Thomas; Weber, Klaus; McVean, Maralee; Funk, Kathleen A

    2015-01-01

    Stem cells have great potential in basic research and are being slowly integrated into toxicological research. This symposium provided an overview of the state of the field, stem cell models, described allogenic stem cell treatments and issues of immunogenicity associated with protein therapeutics, and tehn concentrated on stem cell uses in regenerative medicine focusing on lung and testing strategies on engineered tissues from a pathologist's perspective.

  11. Information on Stem Cell Research

    MedlinePlus

    ... Enhancing Diversity Find People About NINDS Information on Stem Cell Research Research @ NINDS Stem Cell Highlights Submit a hESC ... found here: Human Induced Pluripotent Stem Cells NINDS Stem Cell Research on Campus The Intramural Research Program of NINDS ...

  12. Importance of being Nernst: Synaptic activity and functional relevance in stem cell-derived neurons

    PubMed Central

    Bradford, Aaron B; McNutt, Patrick M

    2015-01-01

    Functional synaptogenesis and network emergence are signature endpoints of neurogenesis. These behaviors provide higher-order confirmation that biochemical and cellular processes necessary for neurotransmitter release, post-synaptic detection and network propagation of neuronal activity have been properly expressed and coordinated among cells. The development of synaptic neurotransmission can therefore be considered a defining property of neurons. Although dissociated primary neuron cultures readily form functioning synapses and network behaviors in vitro, continuously cultured neurogenic cell lines have historically failed to meet these criteria. Therefore, in vitro-derived neuron models that develop synaptic transmission are critically needed for a wide array of studies, including molecular neuroscience, developmental neurogenesis, disease research and neurotoxicology. Over the last decade, neurons derived from various stem cell lines have shown varying ability to develop into functionally mature neurons. In this review, we will discuss the neurogenic potential of various stem cells populations, addressing strengths and weaknesses of each, with particular attention to the emergence of functional behaviors. We will propose methods to functionally characterize new stem cell-derived neuron (SCN) platforms to improve their reliability as physiological relevant models. Finally, we will review how synaptically active SCNs can be applied to accelerate research in a variety of areas. Ultimately, emphasizing the critical importance of synaptic activity and network responses as a marker of neuronal maturation is anticipated to result in in vitro findings that better translate to efficacious clinical treatments. PMID:26240679

  13. Stem cell self-renewal and cancer cell proliferation are regulated by common networks that balance the activation of proto-oncogenes and tumor suppressors.

    PubMed

    Pardal, R; Molofsky, A V; He, S; Morrison, S J

    2005-01-01

    Networks of proto-oncogenes and tumor suppressors that control cancer cell proliferation also regulate stem cell self-renewal and possibly stem cell aging. Proto-oncogenes promote regenerative capacity by promoting stem cell function but must be balanced with tumor suppressor activity to avoid neoplastic proliferation. Conversely, tumor suppressors inhibit regenerative capacity by promoting cell death or senescence in stem cells. For example, the polycomb family proto-oncogene, Bmi-1, is consistently required for the self-renewal of diverse adult stem cells, as well as for the proliferation of cancer cells in the same tissues. Bmi-1 promotes stem cell self-renewal partly by repressing the expression of Ink4a and Arf, tumor suppressor genes that are commonly deleted in cancer. Despite ongoing Bmi-1 expression, Ink4a expression increases with age, potentially reducing stem cell frequency and function. Increased tumor suppressor activity during aging therefore may partly account for age-related declines in stem cell function. Thus, networks of proto-oncogenes and tumor suppressors have evolved to coordinately regulate stem cell function throughout life. Imbalances within such networks cause cancer or premature declines in stem cell activity that resemble accelerated aging.

  14. Reduced synaptic activity in neuronal networks derived from embryonic stem cells of murine Rett syndrome model.

    PubMed

    Barth, Lydia; Sütterlin, Rosmarie; Nenniger, Markus; Vogt, Kaspar E

    2014-01-01

    Neurodevelopmental diseases such as the Rett syndrome (RTT) have received renewed attention, since the mechanisms involved may underlie a broad range of neuropsychiatric disorders such as schizophrenia and autism. In vertebrates early stages in the functional development of neurons and neuronal networks are difficult to study. Embryonic stem cell-derived neurons provide an easily accessible tool to investigate neuronal differentiation and early network formation. We used in vitro cultures of neurons derived from murine embryonic stem cells missing the methyl-CpG-binding protein 2 (MECP2) gene (MeCP2-/y) and from wild type cells of the corresponding background. Cultures were assessed using whole-cell patch-clamp electrophysiology and immunofluorescence. We studied the functional maturation of developing neurons and the activity of the synaptic connections they formed. Neurons exhibited minor differences in the developmental patterns for their intrinsic parameters, such as resting membrane potential and excitability; with the MeCP2-/y cells showing a slightly accelerated development, with shorter action potential half-widths at early stages. There was no difference in the early phase of synapse development, but as the cultures matured, significant deficits became apparent, particularly for inhibitory synaptic activity. MeCP2-/y embryonic stem cell-derived neuronal cultures show clear developmental deficits that match phenotypes observed in slice preparations and thus provide a compelling tool to further investigate the mechanisms behind RTT pathophysiology.

  15. Drosophila's contribution to stem cell research

    PubMed Central

    Singh, Gyanesh

    2016-01-01

    The discovery of Drosophila stem cells with striking similarities to mammalian stem cells has brought new hope for stem cell research. Recent developments in Drosophila stem cell research is bringing wider opportunities for contemporary stem cell biologists. In this regard, Drosophila germ cells are becoming a popular model of stem cell research. In several cases, genes that controlled Drosophila stem cells were later discovered to have functional homologs in mammalian stem cells. Like mammals, Drosophila germline stem cells (GSCs) are controlled by both intrinsic as well as external signals. Inside the Drosophila testes, germline and somatic stem cells form a cluster of cells (the hub). Hub cells depend on JAK-STAT signaling, and, in absence of this signal, they do not self-renew. In Drosophila, significant changes occur within the stem cell niche that contributes to a decline in stem cell number over time. In case of aging Drosophila, somatic niche cells show reduced DE-cadherin and unpaired (Upd) proteins. Unpaired proteins are known to directly decrease stem cell number within the niches, and, overexpression of upd within niche cells restored GSCs in older males also . Stem cells in the midgut of Drosophila are also very promising. Reduced Notch signaling was found to increase the number of midgut progenitor cells. On the other hand, activation of the Notch pathway decreased proliferation of these cells. Further research in this area should lead to the discovery of additional factors that regulate stem and progenitor cells in Drosophila. PMID:26180635

  16. Drosophila's contribution to stem cell research.

    PubMed

    Singh, Gyanesh

    2015-01-01

    The discovery of Drosophila stem cells with striking similarities to mammalian stem cells has brought new hope for stem cell research. Recent developments in Drosophila stem cell research is bringing wider opportunities for contemporary stem cell biologists. In this regard, Drosophila germ cells are becoming a popular model of stem cell research. In several cases, genes that controlled Drosophila stem cells were later discovered to have functional homologs in mammalian stem cells. Like mammals, Drosophila germline stem cells (GSCs) are controlled by both intrinsic as well as external signals. Inside the Drosophila testes, germline and somatic stem cells form a cluster of cells (the hub). Hub cells depend on JAK-STAT signaling, and, in absence of this signal, they do not self-renew. In Drosophila, significant changes occur within the stem cell niche that contributes to a decline in stem cell number over time. In case of aging Drosophila, somatic niche cells show reduced DE-cadherin and unpaired (Upd) proteins. Unpaired proteins are known to directly decrease stem cell number within the niches, and, overexpression of upd within niche cells restored GSCs in older males also . Stem cells in the midgut of Drosophila are also very promising. Reduced Notch signaling was found to increase the number of midgut progenitor cells. On the other hand, activation of the Notch pathway decreased proliferation of these cells. Further research in this area should lead to the discovery of additional factors that regulate stem and progenitor cells in Drosophila. PMID:26180635

  17. Artificial Stem Cell Niches

    PubMed Central

    Lutolf, Matthias P.; Blau, Helen M.

    2011-01-01

    Stem cells are characterized by their dual ability to reproduce themselves (self-renew) and specialize (differentiate), yielding a plethora of daughter cells that maintain and regenerate tissues. In contrast to their embryonic counterparts, adult stem cells retain their unique functions only if they are in intimate contact with an instructive microenvironment, termed stem cell niche. In these niches, stem cells integrate a complex array of molecular signals that, in concert with induced cell-intrinsic regulatory networks, control their function and balance their numbers in response to physiologic demands. This progress report provides a perspective on how advanced materials technologies could be used (i) to engineer and systematically analyze specific aspects of functional stem cells niches in a controlled fashion in vitro and (ii) to target stem cell niches in vivo. Such “artificial niches” constitute potent tools for elucidating stem cell regulatory mechanisms with the capacity to directly impact the development of novel therapeutic strategies for tissue regeneration. PMID:20882496

  18. Quantifying signaling pathway activation to monitor the quality of induced pluripotent stem cells.

    PubMed

    Makarev, Eugene; Fortney, Kristen; Litovchenko, Maria; Braunewell, Karl H; Zhavoronkov, Alex; Atala, Anthony

    2015-09-15

    Many attempts have been made to evaluate the safety and potency of human induced pluripotent stem cells (iPSCs) for clinical applications using transcriptome data, but results so far have been ambiguous or even contradictory. Here, we characterized stem cells at the pathway level, rather than at the gene level as has been the focus of previous work. We meta-analyzed publically-available gene expression data sets and evaluated signaling and metabolic pathway activation profiles for 20 human embryonic stem cell (ESC) lines, 12 human iPSC lines, five embryonic body lines, and six fibroblast cell lines. We demonstrated the close resemblance of iPSCs with ESCs at the pathway level, and provided examples of how pathway activity can be applied to identify iPSC line abnormalities or to predict in vitro differentiation potential. Our results indicate that pathway activation profiling is a promising strategy for evaluating the safety and potency of iPSC lines in translational medicine applications.

  19. Quantifying signaling pathway activation to monitor the quality of induced pluripotent stem cells

    PubMed Central

    Makarev, Eugene; Fortney, Kristen; Litovchenko, Maria; Braunewell, Karl H.; Zhavoronkov, Alex; Atala, Anthony

    2015-01-01

    Many attempts have been made to evaluate the safety and potency of human induced pluripotent stem cells (iPSCs) for clinical applications using transcriptome data, but results so far have been ambiguous or even contradictory. Here, we characterized stem cells at the pathway level, rather than at the gene level as has been the focus of previous work. We meta-analyzed publically-available gene expression data sets and evaluated signaling and metabolic pathway activation profiles for 20 human embryonic stem cell (ESC) lines, 12 human iPSC lines, five embryonic body lines, and six fibroblast cell lines. We demonstrated the close resemblance of iPSCs with ESCs at the pathway level, and provided examples of how pathway activity can be applied to identify iPSC line abnormalities or to predict in vitro differentiation potential. Our results indicate that pathway activation profiling is a promising strategy for evaluating the safety and potency of iPSC lines in translational medicine applications. PMID:26327604

  20. Quantifying signaling pathway activation to monitor the quality of induced pluripotent stem cells.

    PubMed

    Makarev, Eugene; Fortney, Kristen; Litovchenko, Maria; Braunewell, Karl H; Zhavoronkov, Alex; Atala, Anthony

    2015-09-15

    Many attempts have been made to evaluate the safety and potency of human induced pluripotent stem cells (iPSCs) for clinical applications using transcriptome data, but results so far have been ambiguous or even contradictory. Here, we characterized stem cells at the pathway level, rather than at the gene level as has been the focus of previous work. We meta-analyzed publically-available gene expression data sets and evaluated signaling and metabolic pathway activation profiles for 20 human embryonic stem cell (ESC) lines, 12 human iPSC lines, five embryonic body lines, and six fibroblast cell lines. We demonstrated the close resemblance of iPSCs with ESCs at the pathway level, and provided examples of how pathway activity can be applied to identify iPSC line abnormalities or to predict in vitro differentiation potential. Our results indicate that pathway activation profiling is a promising strategy for evaluating the safety and potency of iPSC lines in translational medicine applications. PMID:26327604

  1. p53 activity is selectively licensed in the Drosophila stem cell compartment

    PubMed Central

    Wylie, Annika; Lu, Wan-Jin; D’Brot, Alejandro; Buszczak, Michael; Abrams, John M

    2014-01-01

    Oncogenic stress provokes tumor suppression by p53 but the extent to which this regulatory axis is conserved remains unknown. Using a biosensor to visualize p53 action, we find that Drosophila p53 is selectively active in gonadal stem cells after exposure to stressors that destabilize the genome. Similar p53 activity occurred in hyperplastic growths that were triggered either by the RasV12 oncoprotein or by failed differentiation programs. In a model of transient sterility, p53 was required for the recovery of fertility after stress, and entry into the cell cycle was delayed in p53- stem cells. Together, these observations establish that the stem cell compartment of the Drosophila germline is selectively licensed for stress-induced activation of the p53 regulatory network. Furthermore, the findings uncover ancestral links between p53 and aberrant proliferation that are independent of DNA breaks and predate evolution of the ARF/Mdm2 axis. DOI: http://dx.doi.org/10.7554/eLife.01530.001 PMID:24618896

  2. Activated WNT signaling in postnatal SOX2-positive dental stem cells can drive odontoma formation

    PubMed Central

    Xavier, Guilherme M.; Patist, Amanda L.; Healy, Chris; Pagrut, Ankita; Carreno, Gabriela; Sharpe, Paul T.; Pedro Martinez-Barbera, Juan; Thavaraj, Selvam; Cobourne, Martyn T.; Andoniadou, Cynthia L.

    2015-01-01

    In common with most mammals, humans form only two dentitions during their lifetime. Occasionally, supernumerary teeth develop in addition to the normal complement. Odontoma represent a small group of malformations containing calcified dental tissues of both epithelial and mesenchymal origin, with varying levels of organization, including tooth-like structures. The specific cell type responsible for the induction of odontoma, which retains the capacity to re-initiate de novo tooth development in postnatal tissues, is not known. Here we demonstrate that aberrant activation of WNT signaling by expression of a non-degradable form of β-catenin specifically in SOX2-positive postnatal dental epithelial stem cells is sufficient to generate odontoma containing multiple tooth-like structures complete with all dental tissue layers. Genetic lineage-tracing confirms that odontoma form in a similar manner to normal teeth, derived from both the mutation-sustaining epithelial stem cells and adjacent mesenchymal tissues. Activation of the WNT pathway in embryonic SOX2-positive progenitors results in ectopic expression of secreted signals that promote odontogenesis throughout the oral cavity. Significantly, the inductive potential of epithelial dental stem cells is retained in postnatal tissues, and up-regulation of WNT signaling specifically in these cells is sufficient to promote generation and growth of ectopic malformations faithfully resembling human odontoma. PMID:26411543

  3. Activated WNT signaling in postnatal SOX2-positive dental stem cells can drive odontoma formation.

    PubMed

    Xavier, Guilherme M; Patist, Amanda L; Healy, Chris; Pagrut, Ankita; Carreno, Gabriela; Sharpe, Paul T; Martinez-Barbera, Juan Pedro; Thavaraj, Selvam; Cobourne, Martyn T; Andoniadou, Cynthia L

    2015-09-28

    In common with most mammals, humans form only two dentitions during their lifetime. Occasionally, supernumerary teeth develop in addition to the normal complement. Odontoma represent a small group of malformations containing calcified dental tissues of both epithelial and mesenchymal origin, with varying levels of organization, including tooth-like structures. The specific cell type responsible for the induction of odontoma, which retains the capacity to re-initiate de novo tooth development in postnatal tissues, is not known. Here we demonstrate that aberrant activation of WNT signaling by expression of a non-degradable form of β-catenin specifically in SOX2-positive postnatal dental epithelial stem cells is sufficient to generate odontoma containing multiple tooth-like structures complete with all dental tissue layers. Genetic lineage-tracing confirms that odontoma form in a similar manner to normal teeth, derived from both the mutation-sustaining epithelial stem cells and adjacent mesenchymal tissues. Activation of the WNT pathway in embryonic SOX2-positive progenitors results in ectopic expression of secreted signals that promote odontogenesis throughout the oral cavity. Significantly, the inductive potential of epithelial dental stem cells is retained in postnatal tissues, and up-regulation of WNT signaling specifically in these cells is sufficient to promote generation and growth of ectopic malformations faithfully resembling human odontoma.

  4. Stem Cell Information: Glossary

    MedlinePlus

    ... based therapies Cell culture Cell division Chromosome Clone Cloning Cord blood stem cells Culture medium Differentiation Directed ... Pluripotent Polar body Preimplantation Proliferation Regenerative medicine Reproductive cloning Signals Somatic cell Somatic cell nuclear transfer (SCNT) ...

  5. Invasive and indigenous microbiota impact intestinal stem cell activity through multiple pathways in Drosophila

    PubMed Central

    Buchon, Nicolas; Broderick, Nichole A.; Chakrabarti, Sveta; Lemaitre, Bruno

    2009-01-01

    Gut homeostasis is controlled by both immune and developmental mechanisms, and its disruption can lead to inflammatory disorders or cancerous lesions of the intestine. While the impact of bacteria on the mucosal immune system is beginning to be precisely understood, little is known about the effects of bacteria on gut epithelium renewal. Here, we addressed how both infectious and indigenous bacteria modulate stem cell activity in Drosophila. We show that the increased epithelium renewal observed upon some bacterial infections is a consequence of the oxidative burst, a major defense of the Drosophila gut. Additionally, we provide evidence that the JAK–STAT (Janus kinase–signal transducers and activators of transcription) and JNK (c-Jun NH2 terminal kinase) pathways are both required for bacteria-induced stem cell proliferation. Similarly, we demonstrate that indigenous gut microbiota activate the same, albeit reduced, program at basal levels. Altered control of gut microbiota in immune-deficient or aged flies correlates with increased epithelium renewal. Finally, we show that epithelium renewal is an essential component of Drosophila defense against oral bacterial infection. Altogether, these results indicate that gut homeostasis is achieved by a complex interregulation of the immune response, gut microbiota, and stem cell activity. PMID:19797770

  6. Cytotoxicity Mediated by the Fas Ligand (FasL)-activated Apoptotic Pathway in Stem Cells*

    PubMed Central

    Mazar, Julia; Thomas, Molly; Bezrukov, Ludmila; Chanturia, Alexander; Pekkurnaz, Gulcin; Yin, Shurong; Kuznetsov, Sergei A.; Robey, Pamela G.; Zimmerberg, Joshua

    2009-01-01

    Whereas it is now clear that human bone marrow stromal cells (BMSCs) can be immunosuppressive and escape cytotoxic lymphocytes (CTLs) in vitro and in vivo, the mechanisms of this phenomenon remain controversial. Here, we test the hypothesis that BMSCs suppress immune responses by Fas-mediated apoptosis of activated lymphocytes and find both Fas and FasL expression by primary BMSCs. Jurkat cells or activated lymphocytes were each killed by BMSCs after 72 h of co-incubation. In comparison, the cytotoxic effect of BMSCs on non-activated lymphocytes and on caspase-8(−/−) Jurkat cells was extremely low. Fas/Fc fusion protein strongly inhibited BMSC-induced lymphocyte apoptosis. Although we detected a high level of Fas expression in BMSCs, stimulation of Fas with anti-Fas antibody did not result in the expected BMSC apoptosis, regardless of concentration, suggesting a disruption of the Fas activation pathway. Thus BMSCs may have an endogenous mechanism to evade Fas-mediated apoptosis. Cumulatively, these data provide a parallel between adult stem/progenitor cells and cancer cells, consistent with the idea that stem/progenitor cells can use FasL to prevent lymphocyte attack by inducing lymphocyte apoptosis during the regeneration of injured tissues. PMID:19531476

  7. Skeletal muscle stem cells express anti-apoptotic ErbB receptors during activation from quiescence

    SciTech Connect

    Golding, Jon P. . E-mail: j.p.golding@open.ac.uk; Calderbank, Emma; Partridge, Terence A.; Beauchamp, Jonathan R.

    2007-01-15

    To be effective for tissue repair, satellite cells (the stem cells of adult muscle) must survive the initial activation from quiescence. Using an in vitro model of satellite cell activation, we show that erbB1, erbB2 and erbB3, members of the EGF receptor tyrosine kinase family, appear on satellite cells within 6 h of activation. We show that signalling via erbB2 provides an anti-apoptotic survival mechanism for satellite cells during the first 24 h, as they progress to a proliferative state. Inhibition of erbB2 signalling with AG825 reduced satellite cell numbers, concomitant with elevated caspase-8 activation and TUNEL labelling of apoptotic satellite cells. In serum-free conditions, satellite cell apoptosis could be largely prevented by a mixture of erbB1, erbB3 and erbB4 ligand growth factors, but not by neuregulin alone (erbB3/erbB4 ligand). Furthermore, using inhibitors specific to discrete intracellular signalling pathways, we identify MEK as a pro-apoptotic mediator, and the erbB-regulated factor STAT3 as an anti-apoptotic mediator during satellite cell activation. These results implicate erbB2 signalling in the preservation of a full compliment of satellite cells as they activate in the context of a damaged muscle.

  8. Targeting IL-8 signalling to inhibit breast cancer stem cell activity.

    PubMed

    Singh, Jagdeep K; Simões, Bruno M; Clarke, Robert B; Bundred, Nigel J

    2013-11-01

    Although survival from breast cancer has improved significantly over the past 20 years, disease recurrence remains a significant clinical problem. The concept of stem-like cells in cancer has been gaining currency over the last decade or so, since evidence for stem cell activity in human leukaemia and solid tumours, including breast cancer, was first published. Evidence indicates that this sub-population of cells, known as cancer stem-like cells (CSCs), is responsible for driving tumour formation and disease progression. In breast cancer, there is good evidence that CSCs are intrinsically resistant to conventional chemo-, radio- and endocrine therapies. By evading the effects of these treatments, CSCs are held culpable for disease recurrence. Hence, in order to improve treatment there is a need to develop CSC-targeted therapies. Interleukin-8 (IL-8), an inflammatory cytokine, is upregulated in breast cancer and associated with poor prognostic factors. Accumulating evidence demonstrates that IL-8, through its receptors CXCR1/2, is an important regulator of breast CSC activity. Inhibiting CXCR1/2 signalling has proved efficacious in pre-clinical models of breast cancer providing a good rationale for targeting CXCR1/2 clinically. Here, we discuss the role of IL-8 in breast CSC regulation and development of novel therapies to target CXCR1/2 signalling in breast cancer.

  9. Polycomb Repressive Complex 2 (PRC2) Restricts Hematopoietic Stem Cell Activity

    PubMed Central

    Majewski, Ian J; Blewitt, Marnie E; de Graaf, Carolyn A; McManus, Edward J; Bahlo, Melanie; Hilton, Adrienne A; Hyland, Craig D; Smyth, Gordon K; Corbin, Jason E; Metcalf, Donald; Alexander, Warren S; Hilton, Douglas J

    2008-01-01

    Polycomb group proteins are transcriptional repressors that play a central role in the establishment and maintenance of gene expression patterns during development. Using mice with an N-ethyl-N-nitrosourea (ENU)-induced mutation in Suppressor of Zeste 12 (Suz12), a core component of Polycomb Repressive Complex 2 (PRC2), we show here that loss of Suz12 function enhances hematopoietic stem cell (HSC) activity. In addition to these effects on a wild-type genetic background, mutations in Suz12 are sufficient to ameliorate the stem cell defect and thrombocytopenia present in mice that lack the thrombopoietin receptor (c-Mpl). To investigate the molecular targets of the PRC2 complex in the HSC compartment, we examined changes in global patterns of gene expression in cells deficient in Suz12. We identified a distinct set of genes that are regulated by Suz12 in hematopoietic cells, including eight genes that appear to be highly responsive to PRC2 function within this compartment. These data suggest that PRC2 is required to maintain a specific gene expression pattern in hematopoiesis that is indispensable to normal stem cell function. PMID:18416604

  10. Registered report: Wnt activity defines colon cancer stem cells and is regulated by the microenvironment

    PubMed Central

    Evans, James; Essex, Anthony; Xin, Hong; Amitai, Nurith; Brinton, Lindsey; Griner, Erin; Iorns, Elizabeth

    2015-01-01

    The Reproducibility Project: Cancer Biology seeks to address growing concerns about reproducibility in scientific research by replicating selected results from a substantial number of high-profile papers in the field of cancer biology. The papers, which were published between 2010 and 2012, were selected on the basis of citations and Altmetric scores (Errington et al., 2014). This Registered report describes the proposed replication plan of key experiments from ‘Wnt activity defines colon cancer stem cells and is regulated by the microenvironment’ by Vermeulen and colleagues, published in Nature Cell Biology in 2010 (Vermeulen et al., 2010). The key experiments that will be replicated are those reported in Figures 2F, 6D, and 7E. In these experiments, Vermeulen and colleagues utilize a reporter for Wnt activity and show that colon cancer cells with high levels of Wnt activity also express cancer stem cell markers (Figure 2F; Vermeulen et al., 2010). Additionally, treatment either with conditioned medium derived from myofibroblasts or with hepatocyte growth factor restored clonogenic potential in low Wnt activity colon cancer cells in vitro (Figure 6D; Vermeulen et al., 2010) and in vivo (Figure 7E; Vermeulen et al., 2010). The Reproducibility Project: Cancer Biology is a collaboration between the Center for Open Science and Science Exchange and the results of the replications will be published in eLife. DOI: http://dx.doi.org/10.7554/eLife.07301.001 PMID:26287525

  11. Calcium Alginate Gels as Stem Cell Matrix – Making Paracrine Stem Cell Activity Available for Enhanced Healing after Surgery

    PubMed Central

    Schmitt, Andreas; Rödel, Philipp; Anamur, Cihad; Seeliger, Claudine; Imhoff, Andreas B.; Herbst, Elmar; Vogt, Stephan; van Griensven, Martijn; Winter, Gerhard; Engert, Julia

    2015-01-01

    Regeneration after surgery can be improved by the administration of anabolic growth factors. However, to locally maintain these factors at the site of regeneration is problematic. The aim of this study was to develop a matrix system containing human mesenchymal stem cells (MSCs) which can be applied to the surgical site and allows the secretion of endogenous healing factors from the cells. Calcium alginate gels were prepared by a combination of internal and external gelation. The gelling behaviour, mechanical stability, surface adhesive properties and injectability of the gels were investigated. The permeability of the gels for growth factors was analysed using bovine serum albumin and lysozyme as model proteins. Human MSCs were isolated, cultivated and seeded into the alginate gels. Cell viability was determined by AlamarBlue assay and fluorescence microscopy. The release of human VEGF and bFGF from the cells was determined using an enzyme-linked immunoassay. Gels with sufficient mechanical properties were prepared which remained injectable through a syringe and solidified in a sufficient time frame after application. Surface adhesion was improved by the addition of polyethylene glycol 300,000 and hyaluronic acid. Humans MSCs remained viable for the duration of 6 weeks within the gels. Human VEGF and bFGF was found in quantifiable concentrations in cell culture supernatants of gels loaded with MSCs and incubated for a period of 6 weeks. This work shows that calcium alginate gels can function as immobilization matrices for human MSCs. PMID:25793885

  12. Calcium alginate gels as stem cell matrix-making paracrine stem cell activity available for enhanced healing after surgery.

    PubMed

    Schmitt, Andreas; Rödel, Philipp; Anamur, Cihad; Seeliger, Claudine; Imhoff, Andreas B; Herbst, Elmar; Vogt, Stephan; van Griensven, Martijn; Winter, Gerhard; Engert, Julia

    2015-01-01

    Regeneration after surgery can be improved by the administration of anabolic growth factors. However, to locally maintain these factors at the site of regeneration is problematic. The aim of this study was to develop a matrix system containing human mesenchymal stem cells (MSCs) which can be applied to the surgical site and allows the secretion of endogenous healing factors from the cells. Calcium alginate gels were prepared by a combination of internal and external gelation. The gelling behaviour, mechanical stability, surface adhesive properties and injectability of the gels were investigated. The permeability of the gels for growth factors was analysed using bovine serum albumin and lysozyme as model proteins. Human MSCs were isolated, cultivated and seeded into the alginate gels. Cell viability was determined by AlamarBlue assay and fluorescence microscopy. The release of human VEGF and bFGF from the cells was determined using an enzyme-linked immunoassay. Gels with sufficient mechanical properties were prepared which remained injectable through a syringe and solidified in a sufficient time frame after application. Surface adhesion was improved by the addition of polyethylene glycol 300,000 and hyaluronic acid. Humans MSCs remained viable for the duration of 6 weeks within the gels. Human VEGF and bFGF was found in quantifiable concentrations in cell culture supernatants of gels loaded with MSCs and incubated for a period of 6 weeks. This work shows that calcium alginate gels can function as immobilization matrices for human MSCs.

  13. Complement activation in the context of stem cells and tissue repair

    PubMed Central

    Schraufstatter, Ingrid U; Khaldoyanidi, Sophia K; DiScipio, Richard G

    2015-01-01

    The complement pathway is best known for its role in immune surveillance and inflammation. However, its ability of opsonizing and removing not only pathogens, but also necrotic and apoptotic cells, is a phylogenetically ancient means of initiating tissue repair. The means and mechanisms of complement-mediated tissue repair are discussed in this review. There is increasing evidence that complement activation contributes to tissue repair at several levels. These range from the chemo-attraction of stem and progenitor cells to areas of complement activation, to increased survival of various cell types in the presence of split products of complement, and to the production of trophic factors by cells activated by the anaphylatoxins C3a and C5a. This repair aspect of complement biology has not found sufficient appreciation until recently. The following will examine this aspect of complement biology with an emphasis on the anaphylatoxins C3a and C5a. PMID:26435769

  14. Calpain-Mediated Positional Information Directs Cell Wall Orientation to Sustain Plant Stem Cell Activity, Growth and Development.

    PubMed

    Liang, Zhe; Brown, Roy C; Fletcher, Jennifer C; Opsahl-Sorteberg, Hilde-Gunn

    2015-09-01

    Eukaryotic development and stem cell control depend on the integration of cell positional sensing with cell cycle control and cell wall positioning, yet few factors that directly link these events are known. The DEFECTIVE KERNEL1 (DEK1) gene encoding the unique plant calpain protein is fundamental for development and growth, being essential to confer and maintain epidermal cell identity that allows development beyond the globular embryo stage. We show that DEK1 expression is highest in the actively dividing cells of seeds, meristems and vasculature. We further show that eliminating Arabidopsis DEK1 function leads to changes in developmental cues from the first zygotic division onward, altered microtubule patterns and misshapen cells, resulting in early embryo abortion. Expression of the embryonic marker genes WOX2, ATML1, PIN4, WUS and STM, related to axis organization, cell identity and meristem functions, is also altered in dek1 embryos. By monitoring cell layer-specific DEK1 down-regulation, we show that L1- and 35S-induced down-regulation mainly affects stem cell functions, causing severe shoot apical meristem phenotypes. These results are consistent with a requirement for DEK1 to direct layer-specific cellular activities and set downstream developmental cues. Our data suggest that DEK1 may anchor cell wall positions and control cell division and differentiation, thereby balancing the plant's requirement to maintain totipotent stem cell reservoirs while simultaneously directing growth and organ formation. A role for DEK1 in regulating microtubule-orchestrated cell wall orientation during cell division can explain its effects on embryonic development, and suggests a more general function for calpains in microtubule organization in eukaryotic cells.

  15. Polyphenolic composition of grape stem extracts affects antioxidant activity in endothelial and muscle cells

    PubMed Central

    GOUTZOURELAS, NIKOLAOS; STAGOS, DIMITRIOS; SPANIDIS, YPATIOS; LIOSI, MARIA; APOSTOLOU, ANNA; PRIFTIS, ALEXANDROS; HAROUTOUNIAN, SERKO; SPANDIDOS, DEMETRIOS A.; TSATSAKIS, ARISTIDIS M.; KOURETAS, DEMETRIOS

    2015-01-01

    The aim of the present study was the assessment of the antioxidant effects of polyphenolic extracts derived from the stems of three Greek grape varieties (Moshomayro, Mavrotragano and Mandilaria) in endothelial (EA.hy926) and muscle (C2C12) cells. We also investigated the effects of the polyphenolic composition on the antioxidant effects of the grape stem extracts. For this purpose, the endothelial and muscle cells were treated with low non-cytotoxic concentrations of the extracts for 24 h in order to assess the effects of the extracts on cellular redox status using oxidative stress biomarkers. The oxidative stress markers were thiobarbituric acid reactive substances (TBARS), protein carbonyl (CARB) levels, reactive oxygen species (ROS) levels and glutathione (GSH) levels. The results revealed that treatment of the EA.hy926 cells with Mandilaria extract significantly decreased the TBARS levels by 14.8% and the CARB levels by 25.9 %, while it increased the GSH levels by 15.8% compared to the controls. Moreover, treatment of the EA.hy926 cells with Mavrotragano extract significantly increased the GSH levels by 20.2%, while it significantly decreased the TBARS and CARB levels by 12.5% and 16.6%, respectively. Treatment of the C2C12 cells with Mandilaria extract significantly decreased the TBARS levels by 47.3 %, the CARB levels by 39.0 % and the ROS levels by 21.8%, while it increased the GSH levels by 22.6% compared to the controls. Moreover, treatment of the C2C12 cells with Mavrotragano significantly decreased the TBARS, CARB and ROS levels by 36.2%, 35.9% and 16.5%, respectively. In conclusion, to the best of our knowledgel, our results demonstrate for the first time that treatment with grape stem extracts at low concentrations improves the redox status of endothelial and muscle cells. Thus, grape stem extracts may be used for developing antioxidant food supplements or biofunctional foods. However, it was also found that the polyphenolic composition of grape stem

  16. Polyphenolic composition of grape stem extracts affects antioxidant activity in endothelial and muscle cells.

    PubMed

    Goutzourelas, Nikolaos; Stagos, Dimitrios; Spanidis, Ypatios; Liosi, Maria; Apostolou, Anna; Priftis, Alexandros; Haroutounian, Serko; Spandidos, Demetrios A; Tsatsakis, Aristidis M; Kouretas, Demetrios

    2015-10-01

    The aim of the present study was the assessment of the antioxidant effects of polyphenolic extracts derived from the stems of three Greek grape varieties (Moshomayro, Mavrotragano and Mandilaria) in endothelial (EA.hy926) and muscle (C2C12) cells. We also investigated the effects of the polyphenolic composition on the antioxidant effects of the grape stem extracts. For this purpose, the endothelial and muscle cells were treated with low non-cytotoxic concentrations of the extracts for 24 h in order to assess the effects of the extracts on cellular redox status using oxidative stress biomarkers. The oxidative stress markers were thiobarbituric acid reactive substances (TBARS), protein carbonyl (CARB) levels, reactive oxygen species (ROS) levels and glutathione (GSH) levels. The results revealed that treatment of the EA.hy926 cells with Mandilaria extract significantly decreased the TBARS levels by 14.8% and the CARB levels by 25.9 %, while it increased the GSH levels by 15.8% compared to the controls. Moreover, treatment of the EA.hy926 cells with Mavrotragano extract significantly increased the GSH levels by 20.2%, while it significantly decreased the TBARS and CARB levels by 12.5% and 16.6%, respectively. Treatment of the C2C12 cells with Mandilaria extract significantly decreased the TBARS levels by 47.3 %, the CARB levels by 39.0 % and the ROS levels by 21.8%, while it increased the GSH levels by 22.6% compared to the controls. Moreover, treatment of the C2C12 cells with Mavrotragano significantly decreased the TBARS, CARB and ROS levels by 36.2%, 35.9% and 16.5%, respectively. In conclusion, to the best of our knowledgel, our results demonstrate for the first time that treatment with grape stem extracts at low concentrations improves the redox status of endothelial and muscle cells. Thus, grape stem extracts may be used for developing antioxidant food supplements or biofunctional foods. However, it was also found that the polyphenolic composition of grape stem

  17. Polyphenolic composition of grape stem extracts affects antioxidant activity in endothelial and muscle cells.

    PubMed

    Goutzourelas, Nikolaos; Stagos, Dimitrios; Spanidis, Ypatios; Liosi, Maria; Apostolou, Anna; Priftis, Alexandros; Haroutounian, Serko; Spandidos, Demetrios A; Tsatsakis, Aristidis M; Kouretas, Demetrios

    2015-10-01

    The aim of the present study was the assessment of the antioxidant effects of polyphenolic extracts derived from the stems of three Greek grape varieties (Moshomayro, Mavrotragano and Mandilaria) in endothelial (EA.hy926) and muscle (C2C12) cells. We also investigated the effects of the polyphenolic composition on the antioxidant effects of the grape stem extracts. For this purpose, the endothelial and muscle cells were treated with low non-cytotoxic concentrations of the extracts for 24 h in order to assess the effects of the extracts on cellular redox status using oxidative stress biomarkers. The oxidative stress markers were thiobarbituric acid reactive substances (TBARS), protein carbonyl (CARB) levels, reactive oxygen species (ROS) levels and glutathione (GSH) levels. The results revealed that treatment of the EA.hy926 cells with Mandilaria extract significantly decreased the TBARS levels by 14.8% and the CARB levels by 25.9 %, while it increased the GSH levels by 15.8% compared to the controls. Moreover, treatment of the EA.hy926 cells with Mavrotragano extract significantly increased the GSH levels by 20.2%, while it significantly decreased the TBARS and CARB levels by 12.5% and 16.6%, respectively. Treatment of the C2C12 cells with Mandilaria extract significantly decreased the TBARS levels by 47.3 %, the CARB levels by 39.0 % and the ROS levels by 21.8%, while it increased the GSH levels by 22.6% compared to the controls. Moreover, treatment of the C2C12 cells with Mavrotragano significantly decreased the TBARS, CARB and ROS levels by 36.2%, 35.9% and 16.5%, respectively. In conclusion, to the best of our knowledgel, our results demonstrate for the first time that treatment with grape stem extracts at low concentrations improves the redox status of endothelial and muscle cells. Thus, grape stem extracts may be used for developing antioxidant food supplements or biofunctional foods. However, it was also found that the polyphenolic composition of grape stem

  18. Noninvasive Tracking of Quiescent and Activated Muscle Stem Cell (MuSC) Engraftment Dynamics In Vivo.

    PubMed

    Ho, Andrew T V; Blau, Helen M

    2016-01-01

    Muscle stem cells play a central role in muscle regeneration. Most studies in the field of muscle regeneration focus on the unraveling of muscle stem cell biology to devise strategies for treating failing muscles as seen in aging and muscle-related diseases. However, the common method used in assessing stem cell function in vivo is laborious, as it involves time-consuming immunohistological analyses by microscopy on serial cryo-sections of the muscle post stem cell transplantation. Here we describe an alternative method, which adapts the bioluminescence imaging (BLI) technique to allow noninvasive tracking of engrafted stem-cell function in vivo in real-time. This assay system enables longitudinal studies in the same mice over time and reveals parameters, not feasible by traditional analysis, such as the magnitude and dynamics of engrafted muscle stem cell expansion in vivo in response to a particular drug treatment or muscle injury. PMID:27492173

  19. Reengineering autologous bone grafts with the stem cell activator WNT3A.

    PubMed

    Jing, Wei; Smith, Andrew A; Liu, Bo; Li, Jingtao; Hunter, Daniel J; Dhamdhere, Girija; Salmon, Benjamin; Jiang, Jie; Cheng, Du; Johnson, Chelsey A; Chen, Serafine; Lee, Katherine; Singh, Gurpreet; Helms, Jill A

    2015-04-01

    Autologous bone grafting represents the standard of care for treating bone defects but this biomaterial is unreliable in older patients. The efficacy of an autograft can be traced back to multipotent stem cells residing within the bone graft. Aging attenuates the viability and function of these stem cells, leading to inconsistent rates of bony union. We show that age-related changes in autograft efficacy are caused by a loss in endogenous Wnt signaling. Blocking this endogenous Wnt signal using Dkk1 abrogates autograft efficacy whereas providing a Wnt signal in the form of liposome-reconstituted WNT3A protein (L-WNT3A) restores bone forming potential to autografts from aged animals. The bioengineered autograft exhibits significantly better survival in the hosting site. Mesenchymal and skeletal stem cell populations in the autograft are activated by L-WNT3A and mitotic activity and osteogenic differentiation are significantly enhanced. In a spinal fusion model, aged autografts treated with L-WNT3A demonstrate superior bone forming capacity compared to the standard of care. Thus, a brief incubation in L-WNT3A reliably improves autologous bone grafting efficacy, which has the potential to significantly improve patient care in the elderly.

  20. Reengineering autologous bone grafts with the stem cell activator WNT3A.

    PubMed

    Jing, Wei; Smith, Andrew A; Liu, Bo; Li, Jingtao; Hunter, Daniel J; Dhamdhere, Girija; Salmon, Benjamin; Jiang, Jie; Cheng, Du; Johnson, Chelsey A; Chen, Serafine; Lee, Katherine; Singh, Gurpreet; Helms, Jill A

    2015-04-01

    Autologous bone grafting represents the standard of care for treating bone defects but this biomaterial is unreliable in older patients. The efficacy of an autograft can be traced back to multipotent stem cells residing within the bone graft. Aging attenuates the viability and function of these stem cells, leading to inconsistent rates of bony union. We show that age-related changes in autograft efficacy are caused by a loss in endogenous Wnt signaling. Blocking this endogenous Wnt signal using Dkk1 abrogates autograft efficacy whereas providing a Wnt signal in the form of liposome-reconstituted WNT3A protein (L-WNT3A) restores bone forming potential to autografts from aged animals. The bioengineered autograft exhibits significantly better survival in the hosting site. Mesenchymal and skeletal stem cell populations in the autograft are activated by L-WNT3A and mitotic activity and osteogenic differentiation are significantly enhanced. In a spinal fusion model, aged autografts treated with L-WNT3A demonstrate superior bone forming capacity compared to the standard of care. Thus, a brief incubation in L-WNT3A reliably improves autologous bone grafting efficacy, which has the potential to significantly improve patient care in the elderly. PMID:25682158

  1. MSI2 is required for maintaining activated myelodysplastic syndrome stem cells

    PubMed Central

    Taggart, James; Ho, Tzu-Chieh; Amin, Elianna; Xu, Haiming; Barlowe, Trevor S.; Perez, Alexendar R.; Durham, Benjamin H.; Tivnan, Patrick; Okabe, Rachel; Chow, Arthur; Vu, Ly; Park, Sun Mi; Prieto, Camila; Famulare, Christopher; Patel, Minal; Lengner, Christopher J.; Verma, Amit; Roboz, Gail; Guzman, Monica; Klimek, Virginia M.; Abdel-Wahab, Omar; Leslie, Christina; Nimer, Stephen D.; Kharas, Michael G.

    2016-01-01

    Myelodysplastic syndromes (MDS) are driven by complex genetic and epigenetic alterations. The MSI2 RNA-binding protein has been demonstrated to have a role in acute myeloid leukaemia and stem cell function, but its role in MDS is unknown. Here, we demonstrate that elevated MSI2 expression correlates with poor survival in MDS. Conditional deletion of Msi2 in a mouse model of MDS results in a rapid loss of MDS haematopoietic stem and progenitor cells (HSPCs) and reverses the clinical features of MDS. Inversely, inducible overexpression of MSI2 drives myeloid disease progression. The MDS HSPCs remain dependent on MSI2 expression after disease initiation. Furthermore, MSI2 expression expands and maintains a more activated (G1) MDS HSPC. Gene expression profiling of HSPCs from the MSI2 MDS mice identifies a signature that correlates with poor survival in MDS patients. Overall, we identify a role for MSI2 in MDS representing a therapeutic target in this disease. PMID:26898884

  2. Adult Stem and Progenitor Cells

    NASA Astrophysics Data System (ADS)

    Geraerts, Martine; Verfaillie, Catherine M.

    The discovery of adult stem cells in most adult tissues is the basis of a number of clinical studies that are carried out, with therapeutic use of hematopoietic stem cells as a prime example. Intense scientific debate is still ongoing as to whether adult stem cells may have a greater plasticity than previously thought. Although cells with some features of embryonic stem cells that, among others, express Oct4, Nanog and SSEA1 are isolated from fresh tissue, it is not clear if the greater differentiation potential is acquired during cell culture. Moreover, adult more pluripotent cells do not have all pluripotent characteristics typical for embryonic stem cells. Recently, some elegant studies were published in which adult cells could be completely reprogrammed to embryonic stem cell-like cells by overexpression of some key transcription factors for pluripotency (Oct4, Sox2, Klf4 and c-Myc). It will be interesting for the future to investigate the exact mechanisms underlying this reprogramming and whether similar transcription factor pathways are present and/or can be activated in adult more pluripotent stem cells.

  3. The natural products parthenolide and andrographolide exhibit anti-cancer stem cell activity in multiple myeloma.

    PubMed

    Gunn, Ellen J; Williams, John T; Huynh, Daniel T; Iannotti, Michael J; Han, Changho; Barrios, Francis J; Kendall, Stephen; Glackin, Carlotta A; Colby, David A; Kirshner, Julia

    2011-06-01

    Multiple myeloma (MM) is an incurable plasma cell malignancy where nearly all patients succumb to a relapse. The current preclinical models of MM target the plasma cells, constituting the bulk of the tumor, leaving the cancer stem cells to trigger a relapse. Utilizing a three-dimensional tissue culture system where cells were grown in extracellular matrix designed to reconstruct human bone marrow, we tested the anti-multiple myeloma cancer stem cell (MM-CSC) potential of two natural product inhibitors of nuclear factor κB (NFκB). Here we show that parthenolide and andrographolide are potent anti-MM-CSC agents. Both natural products demonstrated preferential toxicity toward MM-CSCs over non-tumorigenic MM cells. Addition of the bone marrow stromal compartment abrogated andrographolide activity while having no effect on parthenolide cytoxicity. This is the first report of a natural product with anti-CSC activity in myeloma, suggesting that it has the potential to improve the survival of patients with MM by eliminating the relapse-causing MM-CSCs. PMID:21417826

  4. Stem cells and reproduction

    PubMed Central

    Du, Hongling; Taylor, Hugh S.

    2011-01-01

    Purpose of review To review the latest developments in reproductive tract stem cell biology. Recent findings In 2004, two studies indicated that ovaries contain stem cells which form oocytes in adults and that can be cultured in vitro into mature oocytes. A live birth after orthotopic transplantation of cyropreserved ovarian tissue in a woman whose ovaries were damaged by chemotherapy demonstrates the clinical potential of these cells. In the same year, another study provided novel evidence of endometrial regeneration by stem cells in women who received bone marrow transplants. This finding has potential for the use in treatment of uterine disorders. It also supports a new theory for the cause of endometriosis, which may have its origin in ectopic transdifferentiation of stem cells. Several recent studies have demonstrated that fetal cells enter the maternal circulation and generate microchimerism in the mother. The uterus is a dynamic organ permeable to fetal stem cells, capable of transdifferentiation and an end organ in which bone marrow stem cells may differentiate. Finally stem cell transformation can be an underlying cause of ovarian cancer. Summary Whereas we are just beginning to understand stem cells, the potential implications of stem cells to reproductive biology and medicine are apparent. PMID:20305558

  5. Zscan4 Is Activated after Telomere Shortening in Mouse Embryonic Stem Cells

    PubMed Central

    Nakai-Futatsugi, Yoko; Niwa, Hitoshi

    2016-01-01

    Summary ZSCAN4 is a DNA-binding protein that functions for telomere elongation and genomic stability. In vivo, it is specifically expressed at the two-cell stage during mouse development. In vitro, it is transiently expressed in mouse embryonic stem cells (ESCs), only in 5% of the population at one time. Here we attempted to elucidate when, under what circumstances, Zscan4 is activated in ESCs. Using live cell imaging, we monitored the activity of Zscan4 together with the pluripotency marker Rex1. The lengths of the cell cycles in ESCs were diverse. Longer cell cycles were accompanied by shorter telomeres and higher activation of Zscan4. Since activation of Zscan4 is involved in telomere elongation, we speculate that the extended cell cycles accompanied by Zscan4 activation reflect the time for telomere recovery. Rex1 and Zscan4 did not show any correlation. Taken together, we propose that Zscan4 is activated to recover shortened telomeres during extended cell cycles, irrespective of the pluripotent status. PMID:26997646

  6. Stem cells in urology.

    PubMed

    Aboushwareb, Tamer; Atala, Anthony

    2008-11-01

    The shortage of donors for organ transplantation has stimulated research on stem cells as a potential resource for cell-based therapy in all human tissues. Stem cells have been used for regenerative medicine applications in many organ systems, including the genitourinary system. The potential applications for stem cell therapy have, however, been restricted by the ethical issues associated with embryonic stem cell research. Instead, scientists have explored other cell sources, including progenitor and stem cells derived from adult tissues and stem cells derived from the amniotic fluid and placenta. In addition, novel techniques for generating stem cells in the laboratory are being developed. These techniques include somatic cell nuclear transfer, in which the nucleus of an adult somatic cell is placed into an oocyte, and reprogramming of adult cells to induce stem-cell-like behavior. Such techniques are now being used in tissue engineering applications, and some of the most successful experiments have been in the field of urology. Techniques to regenerate bladder tissue have reached the clinic, and exciting progress is being made in other areas, such as regeneration of the kidney and urethra. Cell therapy as a treatment for incontinence and infertility might soon become a reality. Physicians should be optimistic that regenerative medicine and tissue engineering will one day provide mainstream treatment options for urologic disorders.

  7. Stem cells in pharmaceutical biotechnology.

    PubMed

    Zuba-Surma, Ewa K; Józkowicz, Alicja; Dulak, Józef

    2011-11-01

    Multiple populations of stem cells have been indicated to potentially participate in regeneration of injured organs. Especially, embryonic stem cells (ESC) and recently inducible pluripotent stem cells (iPS) receive a marked attention from scientists and clinicians for regenerative medicine because of their high proliferative and differentiation capacities. Despite that ESC and iPS cells are expected to give rise into multiple regenerative applications when their side effects are overcame during appropriate preparation procedures, in fact their most recent application of human ESC may, however, reside in their use as a tool in drug development and disease modeling. This review focuses on the applications of stem cells in pharmaceutical biotechnology. We discuss possible relevance of pluripotent cell stem populations in developing physiological models for any human tissue cell type useful for pharmacological, metabolic and toxicity evaluation necessary in the earliest steps of drug development. The present models applied for preclinical drug testing consist of primary cells or immortalized cell lines that show limitations in terms of accessibility or relevance to their in vivo counterparts. The availability of renewable human cells with functional similarities to their in vivo counterparts is the first landmark for a new generation of cell-based assays. We discuss the approaches for using stem cells as valuable physiological targets of drug activity which may increase the strength of target validation and efficacy potentially resulting in introducing new safer remedies into clinical trials and the marketplace. Moreover, we discuss the possible applications of stem cells for elucidating mechanisms of disease pathogenesis. The knowledge about the mechanisms governing the development and progression of multitude disorders which would come from the cellular models established based on stem cells, may give rise to new therapeutical strategies for such diseases. All

  8. Design, Synthesis, and Osteogenic Activity of Daidzein Analogs on Human Mesenchymal Stem Cells

    PubMed Central

    2013-01-01

    Osteoporosis is caused by an overstimulation of osteoclast activity and the destruction of the bone extracellular matrix. Without the normal architecture, osteoblast cells are unable to rebuild phenotypically normal bone. Hormone replacement therapy with estrogen has been effective in increasing osteoblast activity but also has resulted in the increased incidence of breast and uterine cancer. In this study we designed and synthesized a series of daidzein analogs to investigate their osteogenic induction potentials. Human bone marrow derived mesenchymal stem cells (MSCs) from three different donors were treated with daidzein analogs and demonstrated enhanced osteogenesis when compared to daidzein treatment. The enhanced osteogenic potential of these daidzein analogs resulted in increased osterix (Sp7), alkaline phosphatase (ALP), osteopontin (OPN), and insulin-like growth factor 1 (IGF-1), which are osteogenic transcription factors that regulate the maturation of osteogenic progenitor cells into mature osteoblast cells. PMID:24900787

  9. Evidence for a subventricular zone neural stem cell phagocytic activity stimulated by the vitamin K-dependent factor protein S.

    PubMed

    Ginisty, Aurélie; Gély-Pernot, Aurore; Abaamrane, Loubna; Morel, Franck; Arnault, Patricia; Coronas, Valérie; Benzakour, Omar

    2015-02-01

    Neural stem cells, whose major reservoir in the adult mammalian brain is the subventricular zone (SVZ), ensure neuropoiesis, a process during which many generated cells die. Removal of dead cells and debris by phagocytes is necessary for tissue homeostasis. Using confocal and electron microscopy, we demonstrate that cultured SVZ cells phagocytose both 1 and 2 µm latex beads and apoptotic cell-derived fragments. We determine by flow cytometry that phagocytic cells represent more than 10% of SVZ cultured cells. Phenotyping of SVZ cells using nestin, GFAP, Sox2, or LeX/SSEA and quantification of aldehyde dehydrogenase (ALDH) activity, reveals that cells with neural stem-cell features phagocytose and represent more than 30% of SVZ phagocytic cells. In vivo, nestin-, Sox2-, and ALDH-expressing neural stem-like cells engulfed latex beads or apoptotic cell-derived fragments that were injected into mice lateral brain ventricles. We show also that SVZ cell phagocytic activity is an active process, which depends both on cytoskeleton dynamic and on recognition of phosphatidylserine eat-me signal, and is stimulated by the vitamin K-dependent factor protein S (ProS). ProS neutralizing antibodies inhibit SVZ cell phagocytic activity and exposure of SVZ cells to apoptotic cell-derived fragments induces a transient Mer tyrosine kinase receptor (MerTK) phosphorylation. Conversely, MerTK blocking antibodies impair both basal and ProS-stimulated SVZ cell phagocytic activity. By revealing that neural stem-like cells act within the SVZ neurogenic niche as phagocytes and that the ProS/MerTK path represents an endogenous regulatory mechanism for SVZ cell phagocytic activity, the present report opens-up new perspectives for both stem cell biology and brain physiopathology.

  10. Aldh1 Expression and Activity Increase During Tumor Evolution in Sarcoma Cancer Stem Cell Populations

    PubMed Central

    Martinez-Cruzado, Lucia; Tornin, Juan; Santos, Laura; Rodriguez, Aida; García-Castro, Javier; Morís, Francisco; Rodriguez, Rene

    2016-01-01

    Tumors evolve from initial tumorigenic events into increasingly aggressive behaviors in a process usually driven by subpopulations of cancer stem cells (CSCs). Mesenchymal stromal/stem cells (MSCs) may act as the cell-of-origin for sarcomas, and CSCs that present MSC features have been identified in sarcomas due to their ability to grow as self-renewed floating spheres (tumorspheres). Accordingly, we previously developed sarcoma models using human MSCs transformed with relevant oncogenic events. To study the evolution/emergence of CSC subpopulations during tumor progression, we compared the tumorigenic properties of bulk adherent cultures and tumorsphere-forming subpopulations both in the sarcoma cell-of-origin models (transformed MSCs) and in their corresponding tumor xenograft-derived cells. Tumor formation assays showed that the tumorsphere cultures from xenograft-derived cells, but not from the cell-of-origin models, were enriched in CSCs, providing evidence of the emergence of bona fide CSCs subpopulations during tumor progression. Relevant CSC-related factors, such as ALDH1 and SOX2, were increasingly upregulated in CSCs during tumor progression, and importantly, the increased levels and activity of ALDH1 in these subpopulations were associated with enhanced tumorigenicity. In addition to being a CSC marker, our findings indicate that ALDH1 could also be useful for tracking the malignant potential of CSC subpopulations during sarcoma evolution. PMID:27292183

  11. Aldh1 Expression and Activity Increase During Tumor Evolution in Sarcoma Cancer Stem Cell Populations.

    PubMed

    Martinez-Cruzado, Lucia; Tornin, Juan; Santos, Laura; Rodriguez, Aida; García-Castro, Javier; Morís, Francisco; Rodriguez, Rene

    2016-06-13

    Tumors evolve from initial tumorigenic events into increasingly aggressive behaviors in a process usually driven by subpopulations of cancer stem cells (CSCs). Mesenchymal stromal/stem cells (MSCs) may act as the cell-of-origin for sarcomas, and CSCs that present MSC features have been identified in sarcomas due to their ability to grow as self-renewed floating spheres (tumorspheres). Accordingly, we previously developed sarcoma models using human MSCs transformed with relevant oncogenic events. To study the evolution/emergence of CSC subpopulations during tumor progression, we compared the tumorigenic properties of bulk adherent cultures and tumorsphere-forming subpopulations both in the sarcoma cell-of-origin models (transformed MSCs) and in their corresponding tumor xenograft-derived cells. Tumor formation assays showed that the tumorsphere cultures from xenograft-derived cells, but not from the cell-of-origin models, were enriched in CSCs, providing evidence of the emergence of bona fide CSCs subpopulations during tumor progression. Relevant CSC-related factors, such as ALDH1 and SOX2, were increasingly upregulated in CSCs during tumor progression, and importantly, the increased levels and activity of ALDH1 in these subpopulations were associated with enhanced tumorigenicity. In addition to being a CSC marker, our findings indicate that ALDH1 could also be useful for tracking the malignant potential of CSC subpopulations during sarcoma evolution.

  12. Clinical-scale cultures of cord blood CD34(+) cells to amplify committed progenitors and maintain stem cell activity.

    PubMed

    Ivanovic, Zoran; Duchez, Pascale; Chevaleyre, Jean; Vlaski, Marija; Lafarge, Xavier; Dazey, Bernard; Robert-Richard, Elodie; Mazurier, Frédéric; Boiron, Jean-Michel

    2011-01-01

    We developed a clinical-scale cord blood (CB) cell ex vivo procedure to enable an extensive expansion of committed progenitors--colony-forming cells (CFCs) without impairing very primitive hematopoietic stem cells (HSCs). CD34(++) cells, selected from previously cryopreserved and thawed CB units, were cultured in two steps (diluted 1:4 after 6 days) in the presence of stem cell factor (SCF), fms-related tyrosine kinase 3 ligand (Flt-3L), megakaryocyte growth and development factor (MGDF) (100 ng/ml each), granulocyte-colony stimulating factor (G-CSF) (10 ng/ml) in HP01 serum-free medium. HSC activity was evaluated in a serial transplantation assay, by detection of human cells (CD45, CD33, CD19 and CFC of human origin) in bone marrow (BM) of primary and secondary recipient NOD/SCID mice 6-8 weeks after transplantation. A wide amplification of total cells (∼350-fold), CD34(+) cells (∼100-fold), and CFC (∼130-fold) without impairing the HSC activity was obtained. The activity of a particular HSC subpopulation (SRC(CFC)) was even enhanced.Thus, an extensive ex vivo expansion of CFCs is feasible without impairing the activity of HSCs. This result was enabled by associating antioxidant power of medium with an appropriate cytokine cocktail (i.e., mimicking physiologic effects of a weak oxygenation in hematopoietic environment). PMID:21294956

  13. Clinical-scale cultures of cord blood CD34(+) cells to amplify committed progenitors and maintain stem cell activity.

    PubMed

    Ivanovic, Zoran; Duchez, Pascale; Chevaleyre, Jean; Vlaski, Marija; Lafarge, Xavier; Dazey, Bernard; Robert-Richard, Elodie; Mazurier, Frédéric; Boiron, Jean-Michel

    2011-01-01

    We developed a clinical-scale cord blood (CB) cell ex vivo procedure to enable an extensive expansion of committed progenitors--colony-forming cells (CFCs) without impairing very primitive hematopoietic stem cells (HSCs). CD34(++) cells, selected from previously cryopreserved and thawed CB units, were cultured in two steps (diluted 1:4 after 6 days) in the presence of stem cell factor (SCF), fms-related tyrosine kinase 3 ligand (Flt-3L), megakaryocyte growth and development factor (MGDF) (100 ng/ml each), granulocyte-colony stimulating factor (G-CSF) (10 ng/ml) in HP01 serum-free medium. HSC activity was evaluated in a serial transplantation assay, by detection of human cells (CD45, CD33, CD19 and CFC of human origin) in bone marrow (BM) of primary and secondary recipient NOD/SCID mice 6-8 weeks after transplantation. A wide amplification of total cells (∼350-fold), CD34(+) cells (∼100-fold), and CFC (∼130-fold) without impairing the HSC activity was obtained. The activity of a particular HSC subpopulation (SRC(CFC)) was even enhanced.Thus, an extensive ex vivo expansion of CFCs is feasible without impairing the activity of HSCs. This result was enabled by associating antioxidant power of medium with an appropriate cytokine cocktail (i.e., mimicking physiologic effects of a weak oxygenation in hematopoietic environment).

  14. The Immunosuppressive Activity of Amniotic Membrane Mesenchymal Stem Cells on T Lymphocytes

    PubMed Central

    Alikarami, Fatemeh; Yari, Fatemeh; Amirizadeh, Naser; Nikougoftar, Mahin; Jalili, Mohammad Ali

    2015-01-01

    Background: Mesenchymal Stem Cells (MSCs) are isolated from different sources like placenta. The placenta and its membranes like Amniotic Membrane (AM) are readily available and easy to work with. There is only limited knowledge on the immunomodulatory properties of human Amniotic Membrane-derived Mesenchymal Stem Cells (hAM-MSCs). The aim of this study was to survey the suppressive activity of hAM-MSCs on T lymphocytes in vitro. Methods: Human AMs were obtained after caesarean section births from healthy women. After enzymatic digestion, cells were cultured and hAM-MSCs were obtained. In addition, human T lymphocytes were isolated and co-cultured with hAM-MSCs for 72 hr in the presence or absence of phytohemagglutinin (PHA). Subsequently, proliferation of T cells was analyzed using BrdU and subsequently flow cytometry technique. Besides, the production of IL-4 and IFN-γ was examined by ELISA method. Additionally, the expression of activation markers (CD38, HLA-DR) was studied on T lymphocytes by flow cytometry technique. Results: It was revealed that hAM-MSCs could significantly suppress the proliferation of T lymphocytes (p≤0.01) and significantly decrease the production of IFN-γ by T cells (p<0.05). hAM-MSCs also down regulated the expression of activation markers on the surface of T lymphocytes, CD38 and HLA-DR. The difference was significant between the case and control samples (p<0.05). All the comparisons were carried out between the case (Tcell+PHA+hAM-MSCs) and control (Tcell+PHA) groups. Conclusion: In conclusion, hAM-MSCs could inhibit the (mitogen-activated) T cells even in the absence of blood monocytes. Besides, hAM-MSCs-mediated inhibition of T lymphocytes was combined with down regulation of activation markers. PMID:26306147

  15. Diabetes and stem cell function.

    PubMed

    Fujimaki, Shin; Wakabayashi, Tamami; Takemasa, Tohru; Asashima, Makoto; Kuwabara, Tomoko

    2015-01-01

    Diabetes mellitus is one of the most common serious metabolic diseases that results in hyperglycemia due to defects of insulin secretion or insulin action or both. The present review focuses on the alterations to the diabetic neuronal tissues and skeletal muscle, including stem cells in both tissues, and the preventive effects of physical activity on diabetes. Diabetes is associated with various nervous disorders, such as cognitive deficits, depression, and Alzheimer's disease, and that may be caused by neural stem cell dysfunction. Additionally, diabetes induces skeletal muscle atrophy, the impairment of energy metabolism, and muscle weakness. Similar to neural stem cells, the proliferation and differentiation are attenuated in skeletal muscle stem cells, termed satellite cells. However, physical activity is very useful for preventing the diabetic alteration to the neuronal tissues and skeletal muscle. Physical activity improves neurogenic capacity of neural stem cells and the proliferative and differentiative abilities of satellite cells. The present review proposes physical activity as a useful measure for the patients in diabetes to improve the physiological functions and to maintain their quality of life. It further discusses the use of stem cell-based approaches in the context of diabetes treatment.

  16. Rapid, Dynamic Activation of Müller Glial Stem Cell Responses in Zebrafish

    PubMed Central

    Sifuentes, Christopher J.; Kim, Jung-Woong; Swaroop, Anand; Raymond, Pamela A.

    2016-01-01

    Purpose Zebrafish neurons regenerate from Müller glia following retinal lesions. Genes and signaling pathways important for retinal regeneration in zebrafish have been described, but our understanding of how Müller glial stem cell properties are regulated is incomplete. Mammalian Müller glia possess a latent neurogenic capacity that might be enhanced in regenerative therapies to treat degenerative retinal diseases. Methods To identify transcriptional changes associated with stem cell properties in zebrafish Müller glia, we performed a comparative transcriptome analysis from isolated cells at 8 and 16 hours following an acute photic lesion, prior to the asymmetric division that produces retinal progenitors. Results We report a rapid, dynamic response of zebrafish Müller glia, characterized by activation of pathways related to stress, nuclear factor–κB (NF-κB) signaling, cytokine signaling, immunity, prostaglandin metabolism, circadian rhythm, and pluripotency, and an initial repression of Wnt signaling. When we compared publicly available transcriptomes of isolated mouse Müller glia from two retinal degeneration models, we found that mouse Müller glia showed evidence of oxidative stress, variable responses associated with immune regulation, and repression of pathways associated with pluripotency, development, and proliferation. Conclusions Categories of biological processes/pathways activated following photoreceptor loss in regeneration-competent zebrafish Müller glia, which distinguished them from mouse Müller glia in retinal degeneration models, included cytokine signaling (notably NF-κB), prostaglandin E2 synthesis, expression of core clock genes, and pathways/metabolic states associated with pluripotency. These regulatory mechanisms are relatively unexplored as potential mediators of stem cell properties likely to be important in Müller glial cells for successful retinal regeneration. PMID:27699411

  17. Intraoperative Stem Cell Therapy

    PubMed Central

    Coelho, Mónica Beato; Cabral, Joaquim M.S.; Karp, Jeffrey M.

    2013-01-01

    Stem cells hold significant promise for regeneration of tissue defects and disease-modifying therapies. Although numerous promising stem cell approaches are advancing in clinical trials, intraoperative stem cell therapies offer more immediate hope by integrating an autologous cell source with a well-established surgical intervention in a single procedure. Herein, the major developments in intraoperative stem cell approaches, from in vivo models to clinical studies, are reviewed, and the potential regenerative mechanisms and the roles of different cell populations in the regeneration process are discussed. Although intraoperative stem cell therapies have been shown to be safe and effective for several indications, there are still critical challenges to be tackled prior to adoption into the standard surgical armamentarium. PMID:22809140

  18. Brain tumor stem cells.

    PubMed

    Palm, Thomas; Schwamborn, Jens C

    2010-06-01

    Since the end of the 'no-new-neuron' theory, emerging evidence from multiple studies has supported the existence of stem cells in neurogenic areas of the adult brain. Along with this discovery, neural stem cells became candidate cells being at the origin of brain tumors. In fact, it has been demonstrated that molecular mechanisms controlling self-renewal and differentiation are shared between brain tumor stem cells and neural stem cells and that corruption of genes implicated in these pathways can direct tumor growth. In this regard, future anticancer approaches could be inspired by uncovering such redundancies and setting up treatments leading to exhaustion of the cancer stem cell pool. However, deleterious effects on (normal) neural stem cells should be minimized. Such therapeutic models underline the importance to study the cellular mechanisms implicated in fate decisions of neural stem cells and the oncogenic derivation of adult brain cells. In this review, we discuss the putative origins of brain tumor stem cells and their possible implications on future therapies.

  19. Dasatinib promotes the activation of quiescent hematopoietic stem cells in mice.

    PubMed

    Duyvestyn, Johanna M; Taylor, Samuel J; Dagger, Samantha A; Langdon, Wallace Y

    2016-05-01

    Dasatinib is an orally available broad-spectrum tyrosine kinase inhibitor that is widely used to treat chronic myeloid leukemia. It is also in clinical trials for the treatment of other malignancies, including solid tumors. Despite its wide use, little is known of its effects on normal hematopoietic stem and progenitor cells. Here, we study wild-type mice dosed with dasatinib and find that it causes the transient induction of proliferation of quiescent hematopoietic stem cells (HSCs). This finding was unexpected given the ability of dasatinib to inhibit c-Kit signaling and promote cell cycle arrest in many cell types. The transient induction of HSC proliferation in dasatinib-dosed mice coincided with a marked induction in the expression of Sca-1 and phospho-S6. Also evident at this time was a rapid but transient loss of lineage-committed hematopoietic progenitors that express high levels of c-Kit and the induction of stem cell factor in the serum. These findings suggest that activation of quiescent HSCs is part of a rapid rescue response that restores hematopoietic progenitors to pretreatment levels. This restoration coincides with HSCs returning to quiescence, and the expression of Sca-1 and phospho-S6 reverting to pre-treatment levels, even though dasatinib dosing is maintained. These data suggest that equilibrium is reached between the opposing forces of dasatinib and hematopoietic growth factors. The transient induction of HSC proliferation provided a window of opportunity whereby these cells became sensitive to killing by the cytotoxic drug 5-fluorouracil. PMID:26921649

  20. Tetrandrine identified in a small molecule screen to activate mesenchymal stem cells for enhanced immunomodulation.

    PubMed

    Yang, Zijiang; Concannon, John; Ng, Kelvin S; Seyb, Kathleen; Mortensen, Luke J; Ranganath, Sudhir; Gu, Fangqi; Levy, Oren; Tong, Zhixiang; Martyn, Keir; Zhao, Weian; Lin, Charles P; Glicksman, Marcie A; Karp, Jeffrey M

    2016-07-26

    Pre-treatment or priming of mesenchymal stem cells (MSC) prior to transplantation can significantly augment the immunosuppressive effect of MSC-based therapies. In this study, we screened a library of 1402 FDA-approved bioactive compounds to prime MSC. We identified tetrandrine as a potential hit that activates the secretion of prostaglandin E2 (PGE2), a potent immunosuppressive agent, by MSC. Tetrandrine increased MSC PGE2 secretion through the NF-κB/COX-2 signaling pathway. When co-cultured with mouse macrophages (RAW264.7), tetrandrine-primed MSC attenuated the level of TNF-α secreted by RAW264.7. Furthermore, systemic transplantation of primed MSC into a mouse ear skin inflammation model significantly reduced the level of TNF-α in the inflamed ear, compared to unprimed cells. Screening of small molecules to pre-condition cells prior to transplantation represents a promising strategy to boost the therapeutic potential of cell therapy.

  1. Tetrandrine identified in a small molecule screen to activate mesenchymal stem cells for enhanced immunomodulation

    PubMed Central

    Yang, Zijiang; Concannon, John; Ng, Kelvin S.; Seyb, Kathleen; Mortensen, Luke J.; Ranganath, Sudhir; Gu, Fangqi; Levy, Oren; Tong, Zhixiang; Martyn, Keir; Zhao, Weian; Lin, Charles P.; Glicksman, Marcie A.; Karp, Jeffrey M.

    2016-01-01

    Pre-treatment or priming of mesenchymal stem cells (MSC) prior to transplantation can significantly augment the immunosuppressive effect of MSC-based therapies. In this study, we screened a library of 1402 FDA-approved bioactive compounds to prime MSC. We identified tetrandrine as a potential hit that activates the secretion of prostaglandin E2 (PGE2), a potent immunosuppressive agent, by MSC. Tetrandrine increased MSC PGE2 secretion through the NF-κB/COX-2 signaling pathway. When co-cultured with mouse macrophages (RAW264.7), tetrandrine-primed MSC attenuated the level of TNF-α secreted by RAW264.7. Furthermore, systemic transplantation of primed MSC into a mouse ear skin inflammation model significantly reduced the level of TNF-α in the inflamed ear, compared to unprimed cells. Screening of small molecules to pre-condition cells prior to transplantation represents a promising strategy to boost the therapeutic potential of cell therapy. PMID:27457881

  2. Tetrandrine identified in a small molecule screen to activate mesenchymal stem cells for enhanced immunomodulation.

    PubMed

    Yang, Zijiang; Concannon, John; Ng, Kelvin S; Seyb, Kathleen; Mortensen, Luke J; Ranganath, Sudhir; Gu, Fangqi; Levy, Oren; Tong, Zhixiang; Martyn, Keir; Zhao, Weian; Lin, Charles P; Glicksman, Marcie A; Karp, Jeffrey M

    2016-01-01

    Pre-treatment or priming of mesenchymal stem cells (MSC) prior to transplantation can significantly augment the immunosuppressive effect of MSC-based therapies. In this study, we screened a library of 1402 FDA-approved bioactive compounds to prime MSC. We identified tetrandrine as a potential hit that activates the secretion of prostaglandin E2 (PGE2), a potent immunosuppressive agent, by MSC. Tetrandrine increased MSC PGE2 secretion through the NF-κB/COX-2 signaling pathway. When co-cultured with mouse macrophages (RAW264.7), tetrandrine-primed MSC attenuated the level of TNF-α secreted by RAW264.7. Furthermore, systemic transplantation of primed MSC into a mouse ear skin inflammation model significantly reduced the level of TNF-α in the inflamed ear, compared to unprimed cells. Screening of small molecules to pre-condition cells prior to transplantation represents a promising strategy to boost the therapeutic potential of cell therapy. PMID:27457881

  3. Hematopoietic Stem Cell Activity Is Regulated by Pten Phosphorylation Through a Niche-Dependent Mechanism.

    PubMed

    Li, Jing; Zhang, Jun; Tang, Minghui; Xin, Junping; Xu, Yan; Volk, Andrew; Hao, Caiqin; Hu, Chenglong; Sun, Jiewen; Wei, Wei; Cao, Quichan; Breslin, Peter; Zhang, Jiwang

    2016-08-01

    The phosphorylated form of Pten (p-Pten) is highly expressed in >70% of acute myeloid leukemia samples. However, the role of p-Pten in normal and abnormal hematopoiesis has not been studied. We found that Pten protein levels are comparable among long-term (LT) hematopoietic stem cells (HSCs), short-term (ST) HSCs, and multipotent progenitors (MPPs); however, the levels of p-Pten are elevated during the HSC-to-MPP transition. To study whether p-Pten is involved in regulating self-renewal and differentiation in HSCs, we compared the effects of overexpression of p-Pten and nonphosphorylated Pten (non-p-Pten) on the hematopoietic reconstitutive capacity (HRC) of HSCs. We found that overexpression of non-p-Pten enhances the LT-HRC of HSCs, whereas overexpression of p-Pten promotes myeloid differentiation and compromises the LT-HRC of HSCs. Such phosphorylation-regulated Pten functioning is mediated by repressing the cell:cell contact-induced activation of Fak/p38 signaling independent of Pten's lipid phosphatase activity because both p-Pten and non-p-Pten have comparable activity in repressing PI3K/Akt signaling. Our studies suggest that, in addition to repressing PI3K/Akt/mTor signaling, non-p-Pten maintains HSCs in bone marrow niches via a cell-contact inhibitory mechanism by inhibiting Fak/p38 signaling-mediated proliferation and differentiation. In contrast, p-Pten promotes the proliferation and differentiation of HSCs by enhancing the cell contact-dependent activation of Src/Fak/p38 signaling. Stem Cells 2016;34:2130-2144.

  4. Hematopoietic Stem Cell Activity Is Regulated by Pten Phosphorylation Through a Niche-Dependent Mechanism.

    PubMed

    Li, Jing; Zhang, Jun; Tang, Minghui; Xin, Junping; Xu, Yan; Volk, Andrew; Hao, Caiqin; Hu, Chenglong; Sun, Jiewen; Wei, Wei; Cao, Quichan; Breslin, Peter; Zhang, Jiwang

    2016-08-01

    The phosphorylated form of Pten (p-Pten) is highly expressed in >70% of acute myeloid leukemia samples. However, the role of p-Pten in normal and abnormal hematopoiesis has not been studied. We found that Pten protein levels are comparable among long-term (LT) hematopoietic stem cells (HSCs), short-term (ST) HSCs, and multipotent progenitors (MPPs); however, the levels of p-Pten are elevated during the HSC-to-MPP transition. To study whether p-Pten is involved in regulating self-renewal and differentiation in HSCs, we compared the effects of overexpression of p-Pten and nonphosphorylated Pten (non-p-Pten) on the hematopoietic reconstitutive capacity (HRC) of HSCs. We found that overexpression of non-p-Pten enhances the LT-HRC of HSCs, whereas overexpression of p-Pten promotes myeloid differentiation and compromises the LT-HRC of HSCs. Such phosphorylation-regulated Pten functioning is mediated by repressing the cell:cell contact-induced activation of Fak/p38 signaling independent of Pten's lipid phosphatase activity because both p-Pten and non-p-Pten have comparable activity in repressing PI3K/Akt signaling. Our studies suggest that, in addition to repressing PI3K/Akt/mTor signaling, non-p-Pten maintains HSCs in bone marrow niches via a cell-contact inhibitory mechanism by inhibiting Fak/p38 signaling-mediated proliferation and differentiation. In contrast, p-Pten promotes the proliferation and differentiation of HSCs by enhancing the cell contact-dependent activation of Src/Fak/p38 signaling. Stem Cells 2016;34:2130-2144. PMID:27096933

  5. Differentiation of trophoblast stem cells into giant cells is triggered by p57/Kip2 inhibition of CDK1 activity

    PubMed Central

    Ullah, Zakir; Kohn, Matthew J.; Yagi, Rieko; Vassilev, Lyubomir T.; DePamphilis, Melvin L.

    2008-01-01

    Genome endoreduplication during mammalian development is a rare event for which the mechanism is unknown. It first appears when fibroblast growth factor 4 (FGF4) deprivation induces differentiation of trophoblast stem (TS) cells into the nonproliferating trophoblast giant (TG) cells required for embryo implantation. Here we show that RO3306 inhibition of cyclin-dependent protein kinase 1 (CDK1), the enzyme required to enter mitosis, induced differentiation of TS cells into TG cells. In contrast, RO3306 induced abortive endoreduplication and apoptosis in embryonic stem cells, revealing that inactivation of CDK1 triggers endoreduplication only in cells programmed to differentiate into polyploid cells. Similarly, FGF4 deprivation resulted in CDK1 inhibition by overexpressing two CDK-specific inhibitors, p57/KIP2 and p21/CIP1. TS cell mutants revealed that p57 was required to trigger endoreduplication by inhibiting CDK1, while p21 suppressed expression of the checkpoint protein kinase CHK1, thereby preventing induction of apoptosis. Furthermore, Cdk2−/− TS cells revealed that CDK2 is required for endoreduplication when CDK1 is inhibited. Expression of p57 in TG cells was restricted to G-phase nuclei to allow CDK activation of S phase. Thus, endoreduplication in TS cells is triggered by p57 inhibition of CDK1 with concomitant suppression of the DNA damage response by p21. PMID:18981479

  6. mTOR inhibitors counteract tamoxifen-induced activation of breast cancer stem cells.

    PubMed

    Karthik, Govindasamy-Muralidharan; Ma, Ran; Lövrot, John; Kis, Lorand Levente; Lindh, Claes; Blomquist, Lennart; Fredriksson, Irma; Bergh, Jonas; Hartman, Johan

    2015-10-10

    Breast cancer cells with stem cell characteristics (CSC) are a distinct cell population with phenotypic similarities to mammary stem cells. CSCs are important drivers of tumorigenesis and the metastatic process. Tamoxifen is the most widely used hormonal therapy for estrogen receptor (ER) positive cancers. In our study, tamoxifen was effective in reducing proliferation of ER + adherent cancer cells, but not their CSC population. We isolated, expanded and incubated CSC from seven breast cancers with or without tamoxifen. By genome-wide transcriptional analysis we identified tamoxifen-induced transcriptional pathways associated with ribosomal biogenesis and mRNA translation, both regulated by the mTOR-pathway. We observed induction of the key mTOR downstream targets S6K1, S6RP and 4E-BP1 in-patient derived CSCs by tamoxifen on protein level. Using the mTOR inhibitors rapamycin, everolimus and PF-04691502 (a dual PI3K/mTOR inhibitor) and in combination with tamoxifen, significant reduction in mammosphere formation was observed. Hence, we suggest that the CSC population play a significant role during endocrine resistance through activity of the mTOR pathway. In addition, tamoxifen further stimulates the mTOR-pathway but can be antagonized using mTOR-inhibitors. PMID:26208432

  7. Proteins secreted by embryonic stem cells activate cardiomyocytes through ligand binding pathways.

    PubMed

    LaFramboise, W A; Petrosko, P; Krill-Burger, J M; Morris, D R; McCoy, A R; Scalise, D; Malehorn, D E; Guthrie, R D; Becich, M J; Dhir, R

    2010-03-10

    Human embryonic stem cells (hESC) underlie embryogenesis but paracrine signals associated with the process are unknown. This study was designed to 1) profile native proteins secreted by undifferentiated hESC and 2) determine their biological effects on primary neonatal cardiomyocytes. We utilized multi-analyte, immunochemical assays to characterize media conditioned by undifferentiated hESC versus unconditioned media. Expression profiling was performed on cardiomyocytes subjected to these different media conditions and altered transcripts were mapped to critical pathways. Thirty-two of 109 proteins were significantly elevated in conditioned media ranging in concentration from thrombospondin (57.2+/-5.0 ng/ml) to nerve growth factor (7.4+/-1.2pg/ml) and comprising chemokines, cytokines, growth factors, and proteins involved in cell adhesion and extracellular matrix remodeling. Conditioned media induced karyokinesis, cytokinesis and proliferation in mono- and binucleate cardiomyocytes. Pathway analysis revealed comprehensive activation of the ROCK 1 and 2 G-protein coupled receptor (GPCR) pathway associated with cytokinesis, and the RAS/RAF/MEK/ERK receptor tyrosine kinase (RTK) and JAK/STAT-cytokine pathway involved in cell cycle progression. These results provide a partial database of proteins secreted by pluripotent hESC that potentiate cell division in cardiomyocytes via a paracrine mechanism suggesting a potential role for these stem cell factors in cardiogenesis and cardiac repair.

  8. Neural Stem Cells Restore Hair Growth Through Activation of the Hair Follicle Niche.

    PubMed

    Hwang, Insik; Choi, Kyung-Ah; Park, Hang-Soo; Jeong, Hyesun; Kim, Jeong-Ok; Seol, Ki-Cheon; Kwon, Han-Jin; Park, In-Hyun; Hong, Sunghoi

    2016-01-01

    Several types of hair loss result from the inability of hair follicles to initiate the anagen phase of the hair regeneration cycle. Modulating signaling pathways in the hair follicle niche can stimulate entry into the anagen phase. Despite much effort, stem cell-based or pharmacological therapies to activate the hair follicle niche have not been successful. Here, we set out to test the effect of neural stem cell (NSC) extract on the hair follicle niche for hair regrowth. NSC extracts were applied to the immortalized cell lines HaCaT keratinocytes and dermal papilla cells (DPCs) and the shaven dorsal skin of mice. Treatment with NSC extract dramatically improved the growth of HaCaT keratinocytes and DPCs. In addition, NSC extract enhanced the hair growth of the shaven dorsal skin of mice. In order to determine the molecular signaling pathways regulated by NSCs, we evaluated the expression levels of multiple growth and signaling factors, such as insulin-like growth factor-1 (IGF-1), hepatocyte growth factor (HGF), keratinocyte growth factor (KGF), vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), and bone morphogenetic protein (BMP) family members. We found that treatment with an NSC extract enhanced hair growth by activating hair follicle niches via coregulation of TGF-β and BMP signaling pathways in the telogen phase. We also observed activation and differentiation of intrafollicular hair follicle stem cells, matrix cells, and extrafollicular DPCs in vivo and in vitro. We tested whether activation of growth factor pathways is a major effect of NSC treatment on hair growth by applying the growth factors to mouse skin. Combined growth factors, including TGF-β, significantly increased the hair shaft length and growth rate. DNA damage and cell death were not observed in skin cells of mice treated with the NSC extract for a prolonged period. Overall, our data demonstrate that NSC extract provides an effective approach for promoting

  9. Fish stem cell cultures.

    PubMed

    Hong, Ni; Li, Zhendong; Hong, Yunhan

    2011-04-13

    Stem cells have the potential for self-renewal and differentiation. First stem cell cultures were derived 30 years ago from early developing mouse embryos. These are pluripotent embryonic stem (ES) cells. Efforts towards ES cell derivation have been attempted in other mammalian and non-mammalian species. Work with stem cell culture in fish started 20 years ago. Laboratory fish species, in particular zebrafish and medaka, have been the focus of research towards stem cell cultures. Medaka is the second organism that generated ES cells and the first that gave rise to a spermatogonial stem cell line capable of test-tube sperm production. Most recently, the first haploid stem cells capable of producing whole animals have also been generated from medaka. ES-like cells have been reported also in zebrafish and several marine species. Attempts for germline transmission of ES cell cultures and gene targeting have been reported in zebrafish. Recent years have witnessed the progress in markers and procedures for ES cell characterization. These include the identification of fish homologs/paralogs of mammalian pluripotency genes and parameters for optimal chimera formation. In addition, fish germ cell cultures and transplantation have attracted considerable interest for germline transmission and surrogate production. Haploid ES cell nuclear transfer has proven in medaka the feasibility of semi-cloning as a novel assisted reproductive technology. In this special issue on "Fish Stem Cells and Nuclear Transfer", we will focus our review on medaka to illustrate the current status and perspective of fish stem cells in research and application. We will also mention semi-cloning as a new development to conventional nuclear transfer.

  10. Signal integration by Ca(2+) regulates intestinal stem-cell activity.

    PubMed

    Deng, Hansong; Gerencser, Akos A; Jasper, Heinrich

    2015-12-10

    Somatic stem cells maintain tissue homeostasis by dynamically adjusting proliferation and differentiation in response to stress and metabolic cues. Here we identify Ca(2+) signalling as a central regulator of intestinal stem cell (ISC) activity in Drosophila. We show that dietary L-glutamate stimulates ISC division and gut growth. The metabotropic glutamate receptor (mGluR) is required in ISCs for this response, and for an associated modulation of cytosolic Ca(2+) oscillations that results in sustained high cytosolic Ca(2+) concentrations. High cytosolic Ca(2+) concentrations induce ISC proliferation by regulating Calcineurin and CREB-regulated transcriptional co-activator (Crtc). In response to a wide range of dietary and stress stimuli, ISCs reversibly transition between Ca(2+) oscillation states that represent poised or activated modes of proliferation, respectively. We propose that the dynamic regulation of intracellular Ca(2+) levels allows effective integration of diverse mitogenic signals in ISCs to adapt their proliferative activity to the needs of the tissue. PMID:26633624

  11. Changing Paradigms in Cranio-Facial Regeneration: Current and New Strategies for the Activation of Endogenous Stem Cells

    PubMed Central

    Mele, Luigi; Vitiello, Pietro Paolo; Tirino, Virginia; Paino, Francesca; De Rosa, Alfredo; Liccardo, Davide; Papaccio, Gianpaolo; Desiderio, Vincenzo

    2016-01-01

    Craniofacial area represent a unique district of human body characterized by a very high complexity of tissues, innervation and vascularization, and being deputed to many fundamental function such as eating, speech, expression of emotions, delivery of sensations such as taste, sight, and earing. For this reasons, tissue loss in this area following trauma or for example oncologic resection, have a tremendous impact on patients' quality of life. In the last 20 years regenerative medicine has emerged as one of the most promising approach to solve problem related to trauma, tissue loss, organ failure etc. One of the most powerful tools to be used for tissue regeneration is represented by stem cells, which have been successfully implanted in different tissue/organs with exciting results. Nevertheless, both autologous and allogeneic stem cell transplantation raise many practical and ethical concerns that make this approach very difficult to apply in clinical practice. For this reason different cell free approaches have been developed aiming to the mobilization, recruitment, and activation of endogenous stem cells into the injury site avoiding exogenous cells implant but instead stimulating patients' own stem cells to repair the lesion. To this aim many strategies have been used including functionalized bioscaffold, controlled release of stem cell chemoattractants, growth factors, BMPs, Platelet–Rich-Plasma, and other new strategies such as ultrasound wave and laser are just being proposed. Here we review all the current and new strategies used for activation and mobilization of endogenous stem cells in the regeneration of craniofacial tissue. PMID:26941656

  12. A differential role for CXCR4 in the regulation of normal versus malignant breast stem cell activity.

    PubMed

    Ablett, Matthew P; O'Brien, Ciara S; Sims, Andrew H; Farnie, Gillian; Clarke, Robert B

    2014-02-15

    C-X-C chemokine receptor type 4 (CXCR4) is known to regulate lung, pancreatic and prostate cancer stem cells. In breast cancer, CXCR4 signalling has been reported to be a mediator of metastasis, and is linked to poor prognosis. However its role in normal and malignant breast stem cell function has not been investigated. Anoikis resistant (AR) cells were collected from immortalised (MCF10A, 226L) and malignant (MCF7, T47D, SKBR3) breast cell lines and assessed for stem cell enrichment versus unsorted cells. AR cells had significantly higher mammosphere forming efficiency (MFE) than unsorted cells. The AR normal cells demonstrated increased formation of 3D structures in Matrigel compared to unsorted cells. In vivo, SKBR3 and T47D AR cells had 7- and 130-fold enrichments for tumour formationrespectively, compared with unsorted cells. AR cells contained significantly elevated CXCR4 transcript and protein levels compared to unsorted cells. Importantly, CXCR4 mRNA was higher in stem cell-enriched CD44+/CD24- patient-derived breast cancer cells compared to non-enriched cells. CXCR4 stimulation by its ligand SDF-1 reduced MFE of the normal breast cells lines but increased the MFE in T47D and patient-derived breast cancer cells. CXCR4 inhibition by AMD3100 increased stem cell activity but reduced the self-renewal capacity of the malignant breast cell line T47D. CXCR4+ FACS sorted MCF7 cells demonstrated a significantly increased MFE compared with CXCR4- cells. This significant increase in MFE was further demonstrated in CXCR4 over-expressing MCF7 cells which also had an increase in self-renewal compared to parental cells. A greater reduction in self-renewal following CXCR4 inhibition in the CXCR4 over-expressing cells compared with parental cells was also observed. Our data establish for the first time that CXCR4 signalling has contrasting effects on normal and malignant breast stem cell activity. Here, we demonstrate that CXCR4 signalling specifically regulates breast

  13. A differential role for CXCR4 in the regulation of normal versus malignant breast stem cell activity

    PubMed Central

    Ablett, Matthew P.; O'Brien, Ciara S.; Sims, Andrew H.; Farnie, Gillian; Clarke, Robert B.

    2014-01-01

    C-X-C chemokine receptor type 4 (CXCR4) is known to regulate lung, pancreatic and prostate cancer stem cells. In breast cancer, CXCR4 signalling has been reported to be a mediator of metastasis, and is linked to poor prognosis. However its role in normal and malignant breast stem cell function has not been investigated. Anoikis resistant (AR) cells were collected from immortalised (MCF10A, 226L) and malignant (MCF7, T47D, SKBR3) breast cell lines and assessed for stem cell enrichment versus unsorted cells. AR cells had significantly higher mammosphere forming efficiency (MFE) than unsorted cells. The AR normal cells demonstrated increased formation of 3D structures in Matrigel compared to unsorted cells. In vivo, SKBR3 and T47D AR cells had 7- and 130-fold enrichments for tumour formation respectively, compared with unsorted cells. AR cells contained significantly elevated CXCR4 transcript and protein levels compared to unsorted cells. Importantly, CXCR4 mRNA was higher in stem cell-enriched CD44+ /CD24− - patient-derived breast cancer cells compared to non-enriched cells. CXCR4 stimulation by its ligand SDF-1 reduced MFE of the normal breast cells lines but increased the MFE in T47D and patient-derived breast cancer cells. CXCR4 inhibition by AMD3100 increased stem cell activity but reduced the self-renewal capacity of the malignant breast cell line T47D. CXCR4 + FACS sorted MCF7 cells demonstrated a significantly increased MFE compared with CXCR4- cells. This significant increase in MFE was further demonstrated in CXCR4 over-expressing MCF7 cells which also had an increase in self-renewal compared to parental cells. A greater reduction in self-renewal following CXCR4 inhibition in the CXCR4 over-expressing cells compared with parental cells was also observed. Our data establish for the first time that CXCR4 signalling has contrasting effects on normal and malignant breast stem cell activity. Here, we demonstrate that CXCR4 signalling specifically regulates

  14. Monocytes and macrophages, implications for breast cancer migration and stem cell-like activity and treatment

    PubMed Central

    Ward, Rebecca; Sims, Andrew H.; Lee, Alexander; Lo, Christina; Wynne, Luke; Yusuf, Humza; Gregson, Hannah; Lisanti, Michael P.; Sotgia, Federica; Landberg, Göran; Lamb, Rebecca

    2015-01-01

    Macrophages are a major cellular constituent of the tumour stroma and contribute to breast cancer prognosis. The precise role and treatment strategies to target macrophages remain elusive. As macrophage infiltration is associated with poor prognosis and high grade tumours we used the THP-1 cell line to model monocyte-macrophage differentiation in co-culture with four breast cancer cell lines (MCF7, T47D, MDA-MB-231, MDA-MB-468) to model in vivo cellular interactions. Polarisation into M1 and M2 subtypes was confirmed by specific cell marker expression of ROS and HLA-DR, respectively. Co-culture with all types of macrophage increased migration of ER-positive breast cancer cell lines, while M2-macrophages increased mammosphere formation, compared to M1-macrophages, in all breast cancer cells lines. Treatment of cells with Zoledronate in co-culture reduced the “pro-tumourigenic” effects (increased mammospheres/migration) exerted by macrophages. Direct treatment of breast cancer cells in homotypic culture was unable to reduce migration or mammosphere formation. Macrophages promote “pro-tumourigenic” cellular characteristics of breast cancer cell migration and stem cell activity. Zoledronate targets macrophages within the microenvironment which in turn, reduces the “pro-tumourigenic” characteristics of breast cancer cells. Zoledronate offers an exciting new treatment strategy for both primary and metastatic breast cancer. PMID:26008983

  15. Stem cells in dermatology.

    PubMed

    Ogliari, Karolyn Sassi; Marinowic, Daniel; Brum, Dario Eduardo; Loth, Fabrizio

    2014-01-01

    Preclinical and clinical research have shown that stem cell therapy could be a promising therapeutic option for many diseases in which current medical treatments do not achieve satisfying results or cure. This article describes stem cells sources and their therapeutic applications in dermatology today.

  16. Stem Cell Transplants (For Teens)

    MedlinePlus

    ... How Can I Help a Friend Who Cuts? Stem Cell Transplants KidsHealth > For Teens > Stem Cell Transplants Print ... Does it Take to Recover? Coping What Are Stem Cells? As you probably remember from biology class, every ...

  17. Role of SUMO activating enzyme in cancer stem cell maintenance and self-renewal

    PubMed Central

    Du, Li; Li, Yi-Jia; Fakih, Marwan; Wiatrek, Rebecca L.; Duldulao, Marjun; Chen, Zhenbin; Chu, Peiguo; Garcia-Aguilar, Julio; Chen, Yuan

    2016-01-01

    Cancer stem cells (CSCs) have key roles in treatment resistance, tumour metastasis and relapse. Using colorectal cancer (CC) cell lines, patient-derived xenograft (PDX) tissues and patient tissues, here we report that CC CSCs, which resist chemoradiation, have higher SUMO activating enzyme (E1) and global SUMOylation levels than non-CSCs. Knockdown of SUMO E1 or SUMO conjugating enzyme (E2) inhibits CC CSC maintenance and self-renewal, while overexpression of SUMO E1 or E2 increases CC cell stemness. We found that SUMOylation regulates CSCs through Oct-1, a transcription factor for aldehyde dehydrogenases (ALDHs). ALDH activity is not only a marker for CSCs but also important in CSC biology. SUMO does not modify Oct-1 directly, but regulates the expression of TRIM21 that enhances Oct-1 ubiquitination and, consequently, reducing Oct-1 stability. In summary, our findings suggest that SUMOylation could be a target to inhibit CSCs and ultimately to reduce treatment resistance, tumour metastasis and relapse. PMID:27465491

  18. Hedgehog signaling activation induces stem cell proliferation and hormone release in the adult pituitary gland

    PubMed Central

    Pyczek, Joanna; Buslei, Rolf; Schult, David; Hölsken, Annett; Buchfelder, Michael; Heß, Ina; Hahn, Heidi; Uhmann, Anja

    2016-01-01

    Hedgehog (HH) signaling is known to be essential during the embryonal development of the pituitary gland but the knowledge about its role in the adult pituitary and in associated tumors is sparse. In this report we investigated the effect of excess Hh signaling activation in murine pituitary explants and analyzed the HH signaling status of human adenopituitary lobes and a large cohort of pituitary adenomas. Our data show that excess Hh signaling led to increased proliferation of Sox2+ and Sox9+ adult pituitary stem cells and to elevated expression levels of adrenocorticotropic hormone (Acth), growth hormone (Gh) and prolactin (Prl) in the adult gland. Inhibition of the pathway by cyclopamine reversed these effects indicating that active Hh signaling positively regulates proliferative processes of adult pituitary stem cells and hormone production in the anterior pituitary. Since hormone producing cells of the adenohypophysis as well as ACTH-, GH- and PRL-immunopositive adenomas express SHH and its target GLI1, we furthermore propose that excess HH signaling is involved in the development/maintenance of hormone-producing pituitary adenomas. These findings advance the understanding of physiological hormone regulation and may open new treatment options for pituitary tumors. PMID:27109116

  19. Proteinase-Activated Receptor 1 (PAR1) Regulates Leukemic Stem Cell Functions

    PubMed Central

    Bäumer, Nicole; Krause, Annika; Köhler, Gabriele; Lettermann, Stephanie; Evers, Georg; Hascher, Antje; Bäumer, Sebastian; Berdel, Wolfgang E.

    2014-01-01

    External signals that are mediated by specific receptors determine stem cell fate. The thrombin receptor PAR1 plays an important role in haemostasis, thrombosis and vascular biology, but also in tumor biology and angiogenesis. Its expression and function in hematopoietic stem cells is largely unknown. Here, we analyzed expression and function of PAR1 in primary hematopoietic cells and their leukemic counterparts. AML patients' blast cells expressed much lower levels of PAR1 mRNA and protein than CD34+ progenitor cells. Constitutive Par1-deficiency in adult mice did not affect engraftment or stem cell potential of hematopoietic cells. To model an AML with Par1-deficiency, we retrovirally introduced the oncogene MLL-AF9 in wild type and Par1−/− hematopoietic progenitor cells. Par1-deficiency did not alter initial leukemia development. However, the loss of Par1 enhanced leukemic stem cell function in vitro and in vivo. Re-expression of PAR1 in Par1−/− leukemic stem cells delayed leukemogenesis in vivo. These data indicate that Par1 contributes to leukemic stem cell maintenance. PMID:24740120

  20. ADAR1 Activation Drives Leukemia Stem Cell Self-Renewal by Impairing Let-7 Biogenesis.

    PubMed

    Zipeto, Maria Anna; Court, Angela C; Sadarangani, Anil; Delos Santos, Nathaniel P; Balaian, Larisa; Chun, Hye-Jung; Pineda, Gabriel; Morris, Sheldon R; Mason, Cayla N; Geron, Ifat; Barrett, Christian; Goff, Daniel J; Wall, Russell; Pellecchia, Maurizio; Minden, Mark; Frazer, Kelly A; Marra, Marco A; Crews, Leslie A; Jiang, Qingfei; Jamieson, Catriona H M

    2016-08-01

    Post-transcriptional adenosine-to-inosine RNA editing mediated by adenosine deaminase acting on RNA1 (ADAR1) promotes cancer progression and therapeutic resistance. However, ADAR1 editase-dependent mechanisms governing leukemia stem cell (LSC) generation have not been elucidated. In blast crisis chronic myeloid leukemia (BC CML), we show that increased JAK2 signaling and BCR-ABL1 amplification activate ADAR1. In a humanized BC CML mouse model, combined JAK2 and BCR-ABL1 inhibition prevents LSC self-renewal commensurate with ADAR1 downregulation. Lentiviral ADAR1 wild-type, but not an editing-defective ADAR1(E912A) mutant, induces self-renewal gene expression and impairs biogenesis of stem cell regulatory let-7 microRNAs. Combined RNA sequencing, qRT-PCR, CLIP-ADAR1, and pri-let-7 mutagenesis data suggest that ADAR1 promotes LSC generation via let-7 pri-microRNA editing and LIN28B upregulation. A small-molecule tool compound antagonizes ADAR1's effect on LSC self-renewal in stromal co-cultures and restores let-7 biogenesis. Thus, ADAR1 activation represents a unique therapeutic vulnerability in LSCs with active JAK2 signaling. PMID:27292188

  1. Human α(2)β(1)(HI) CD133(+VE) epithelial prostate stem cells express low levels of active androgen receptor.

    PubMed

    Williamson, Stuart C; Hepburn, Anastasia C; Wilson, Laura; Coffey, Kelly; Ryan-Munden, Claudia A; Pal, Deepali; Leung, Hing Y; Robson, Craig N; Heer, Rakesh

    2012-01-01

    Stem cells are thought to be the cell of origin in malignant transformation in many tissues, but their role in human prostate carcinogenesis continues to be debated. One of the conflicts with this model is that cancer stem cells have been described to lack androgen receptor (AR) expression, which is of established importance in prostate cancer initiation and progression. We re-examined the expression patterns of AR within adult prostate epithelial differentiation using an optimised sensitive and specific approach examining transcript, protein and AR regulated gene expression. Highly enriched populations were isolated consisting of stem (α(2)β(1)(HI) CD133(+VE)), transiently amplifying (α(2)β(1)(HI) CD133(-VE)) and terminally differentiated (α(2)β(1)(LOW) CD133(-VE)) cells. AR transcript and protein expression was confirmed in α(2)β(1)(HI) CD133(+VE) and CD133(-VE) progenitor cells. Flow cytometry confirmed that median (±SD) fraction of cells expressing AR were 77% (±6%) in α(2)β(1)(HI) CD133(+VE) stem cells and 68% (±12%) in α(2)β(1)(HI) CD133(-VE) transiently amplifying cells. However, 3-fold lower levels of total AR protein expression (peak and median immunofluorescence) were present in α(2)β(1)(HI) CD133(+VE) stem cells compared with differentiated cells. This finding was confirmed with dual immunostaining of prostate sections for AR and CD133, which again demonstrated low levels of AR within basal CD133(+VE) cells. Activity of the AR was confirmed in prostate progenitor cells by the expression of low levels of the AR regulated genes PSA, KLK2 and TMPRSS2. The confirmation of AR expression in prostate progenitor cells allows integration of the cancer stem cell theory with the established models of prostate cancer initiation based on a functional AR. Further study of specific AR functions in prostate stem and differentiated cells may highlight novel mechanisms of prostate homeostasis and insights into tumourigenesis.

  2. Zinc Chloride Transiently Maintains Mouse Embryonic Stem Cell Pluripotency by Activating Stat3 Signaling

    PubMed Central

    Hu, Jing; Yang, Zhiyong; Wang, Jinbo; Yu, Jia; Guo, Jing; Liu, Shiying; Qian, Chunmei; Song, Liwen; Wu, Yi; Cheng, Jiajing

    2016-01-01

    An improved understanding of the pluripotency maintenance of embryonic stem (ES) cells is important for investigations of early embryo development and for cell replacement therapy, but the mechanism behind pluripotency is still incompletely understood. Recent findings show that zinc, an essential trace element in humans, is critically involved in regulating various signaling pathways and genes expression. However, its role in ES cell fate determination remains to be further explored. Here we showed that 2μM zinc chloride (ZnCl2) transiently maintained mouse ES cell pluripotency in vitro. The cultured mouse ES cells remained undifferentiated under 2μM ZnCl2 treatment in leukemia inhibitory factor (LIF) withdrawal, retinoic acid (RA) or embryoid bodies (EBs) differentiation assays. In addition, ZnCl2 increased pluripotency genes expression and inhibited differentiation genes expression. Further mechanistic studies revealed that ZnCl2 transiently activated signal transducers and activators of transcription 3 (Stat3) signaling through promoting Stat3 phosphorylation. Inhibition of Stat3 signaling abrogated the effects of ZnCl2 on mouse ES cell pluripotency. Taken together, this study demonstrated a critical role of zinc in the pluripotency maintenance of mouse ES cells, as well as an important regulator of Stat3 signaling. PMID:26910359

  3. Activation of cardiac progenitor cells through paracrine effects of mesenchymal stem cells

    SciTech Connect

    Nakanishi, Chiaki; Yamagishi, Masakazu; Yamahara, Kenichi; Hagino, Ikuo; Mori, Hidezo; Sawa, Yoshiki; Yagihara, Toshikatsu; Kitamura, Soichiro; Nagaya, Noritoshi

    2008-09-12

    Mesenchymal stem cells (MSC) transplantation has been proved to be promising strategy to treat the failing heart. The effect of MSC transplantation is thought to be mediated mainly in a paracrine manner. Recent reports have suggested that cardiac progenitor cells (CPC) reside in the heart. In this study, we investigated whether MSC had paracrine effects on CPC in vitro. CPC were isolated from the neonatal rat heart using an explant method. MSC were isolated from the adult rat bone marrow. MSC-derived conditioned medium promoted proliferation of CPC and inhibited apoptosis of CPC induced by hypoxia and serum starvation. Chemotaxis chamber assay demonstrated that MSC-derived conditioned medium enhanced migration of CPC. Furthermore, MSC-derived conditioned medium upregulated expression of cardiomyocyte-related genes in CPC such as {beta}-myosin heavy chain ({beta}-MHC) and atrial natriuretic peptide (ANP). In conclusion, MSC-derived conditioned medium had protective effects on CPC and enhanced their migration and differentiation.

  4. Monocytes Induce STAT3 Activation in Human Mesenchymal Stem Cells to Promote Osteoblast Formation

    PubMed Central

    Nicolaidou, Vicky; Wong, Mei Mei; Redpath, Andia N.; Ersek, Adel; Baban, Dilair F.; Williams, Lynn M.; Cope, Andrew P.; Horwood, Nicole J.

    2012-01-01

    A major therapeutic challenge is how to replace bone once it is lost. Bone loss is a characteristic of chronic inflammatory and degenerative diseases such as rheumatoid arthritis and osteoporosis. Cells and cytokines of the immune system are known to regulate bone turnover by controlling the differentiation and activity of osteoclasts, the bone resorbing cells. However, less is known about the regulation of osteoblasts (OB), the bone forming cells. This study aimed to investigate whether immune cells also regulate OB differentiation. Using in vitro cell cultures of human bone marrow-derived mesenchymal stem cells (MSC), it was shown that monocytes/macrophages potently induced MSC differentiation into OBs. This was evident by increased alkaline phosphatase (ALP) after 7 days and the formation of mineralised bone nodules at 21 days. This monocyte-induced osteogenic effect was mediated by cell contact with MSCs leading to the production of soluble factor(s) by the monocytes. As a consequence of these interactions we observed a rapid activation of STAT3 in the MSCs. Gene profiling of STAT3 constitutively active (STAT3C) infected MSCs using Illumina whole human genome arrays showed that Runx2 and ALP were up-regulated whilst DKK1 was down-regulated in response to STAT3 signalling. STAT3C also led to the up-regulation of the oncostatin M (OSM) and LIF receptors. In the co-cultures, OSM that was produced by monocytes activated STAT3 in MSCs, and neutralising antibodies to OSM reduced ALP by 50%. These data indicate that OSM, in conjunction with other mediators, can drive MSC differentiation into OB. This study establishes a role for monocyte/macrophages as critical regulators of osteogenic differentiation via OSM production and the induction of STAT3 signalling in MSCs. Inducing the local activation of STAT3 in bone cells may be a valuable tool to increase bone formation in osteoporosis and arthritis, and in localised bone remodelling during fracture repair. PMID:22802946

  5. Autophagy in stem cells

    PubMed Central

    Guan, Jun-Lin; Simon, Anna Katharina; Prescott, Mark; Menendez, Javier A.; Liu, Fei; Wang, Fen; Wang, Chenran; Wolvetang, Ernst; Vazquez-Martin, Alejandro; Zhang, Jue

    2013-01-01

    Autophagy is a highly conserved cellular process by which cytoplasmic components are sequestered in autophagosomes and delivered to lysosomes for degradation. As a major intracellular degradation and recycling pathway, autophagy is crucial for maintaining cellular homeostasis as well as remodeling during normal development, and dysfunctions in autophagy have been associated with a variety of pathologies including cancer, inflammatory bowel disease and neurodegenerative disease. Stem cells are unique in their ability to self-renew and differentiate into various cells in the body, which are important in development, tissue renewal and a range of disease processes. Therefore, it is predicted that autophagy would be crucial for the quality control mechanisms and maintenance of cellular homeostasis in various stem cells given their relatively long life in the organisms. In contrast to the extensive body of knowledge available for somatic cells, the role of autophagy in the maintenance and function of stem cells is only beginning to be revealed as a result of recent studies. Here we provide a comprehensive review of the current understanding of the mechanisms and regulation of autophagy in embryonic stem cells, several tissue stem cells (particularly hematopoietic stem cells), as well as a number of cancer stem cells. We discuss how recent studies of different knockout mice models have defined the roles of various autophagy genes and related pathways in the regulation of the maintenance, expansion and differentiation of various stem cells. We also highlight the many unanswered questions that will help to drive further research at the intersection of autophagy and stem cell biology in the near future. PMID:23486312

  6. Optimized dissociation protocol for isolating human glioma stem cells from tumorspheres via fluorescence-activated cell sorting.

    PubMed

    Lv, Donglai; Ma, Qing-Hua; Duan, Jiang-Jie; Wu, Hai-Bo; Zhao, Xi-Long; Yu, Shi-Cang; Bian, Xiu-Wu

    2016-07-10

    Fluorescence-activated cell sorting (FACS) based on the surface marker CD133 is the most common method for isolating glioma stem cells (GSCs) from heterogeneous glioma cell populations. Optimization of this method will have profound implications for the future of GSC research. Five commonly used digestion reagents, Liberase-TL, trypsin, TrypLE, Accutase, and non-enzymatic cell dissociation solution (NECDS), were used to dissociate glioma tumorspheres derived from two primary glioma specimens (091214 and 090116) and the cell lines U87 and T98G. The dissociation time, cell viability, retention of CD133, and stemness capacity were assessed. The results showed that single cells derived from the Liberase-TL (200 µg/ml) group exhibited high viability and less damage to the antigen CD133. However, the efficiency of NECDS for dissociating the tumorspheres into single cells was fairly low. Meanwhile, the use of this digestion reagent resulted in obvious cellular and antigenic impairments. Taken together, Liberase-TL (200 µg/ml) is an ideal reagent for isolating GSCs from tumorspheres. In contrast, the use of NECDS for such a protocol should be carefully considered. PMID:27091400

  7. CCL2 enhances pluripotency of human induced pluripotent stem cells by activating hypoxia related genes.

    PubMed

    Hasegawa, Yuki; Tang, Dave; Takahashi, Naoko; Hayashizaki, Yoshihide; Forrest, Alistair R R; Suzuki, Harukazu

    2014-01-01

    Standard culture of human induced pluripotent stem cells (hiPSCs) requires basic Fibroblast Growth Factor (bFGF) to maintain the pluripotent state, whereas hiPSC more closely resemble epiblast stem cells than true naïve state ES which requires LIF to maintain pluripotency. Here we show that chemokine (C-C motif) ligand 2 (CCL2) enhances the expression of pluripotent marker genes through the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) protein. Moreover, comparison of transcriptomes between hiPSCs cultured with CCL2 versus with bFGF, we found that CCL2 activates hypoxia related genes, suggesting that CCL2 enhanced pluripotency by inducing a hypoxic-like response.Further, we show that hiPSCs cultured with CCL2 can differentiate at a higher efficiency than culturing withjust bFGF and we show CCL2 can be used in feeder-free conditions [corrected]. Taken together, our finding indicates the novel functions of CCL2 in enhancing its pluripotency in hiPSCs. PMID:24957798

  8. Blockage of caspase-1 activation ameliorates bone marrow inflammation in mice after hematopoietic stem cell transplantation.

    PubMed

    Qiao, Jianlin; Wu, Jinyan; Li, Yuanyuan; Xia, Yuan; Chu, Peipei; Qi, Kunming; Yan, Zhiling; Yao, Haina; Liu, Yun; Xu, Kailin; Zeng, Lingyu

    2016-01-01

    Conditioning regimens before hematopoietic stem cell transplantation (HSCT), cause damage to bone marrow and inflammation. Whether inflammasomes are involved in bone marrow inflammation remains unclear. The study aims to evaluate the role of inflammasomes in bone marrow inflammation after HSCT. On days 7, 14, 21 and 28 after HSCT, mice were sacrificed for analysis of bone marrow inflammation, pro-inflammatory cytokines secretion, inflammasomes expression and caspase-1 activation. Bone marrow inflammation with neutrophils and macrophages infiltration was observed after HSCT. Secretion of IL-1β, IL-18, TNF-α and IL-6 were elevated, with increased caspase-1 activation and inflammasomes expression. Caspase-1 inhibitor administration after HSCT significantly reduced infiltration of neutrophils and macrophages into bone marrow and increased the numbers of megakaryocytes and platelets. In conclusion, inflammasomes activation is involved in bone marrow inflammation after HSCT and caspase-1 inhibition attenuates bone marrow inflammation and promoted hematopoietic reconstitution, suggesting targeting caspase-1 might be beneficial for improving HSCT outcomes.

  9. Engineered heart tissue enables study of residual undifferentiated embryonic stem cell activity in a cardiac environment.

    PubMed

    Dengler, Jana; Song, Hannah; Thavandiran, Nimalan; Massé, Stéphane; Wood, Geoffrey A; Nanthakumar, Kumaraswamy; Zandstra, Peter W; Radisic, Milica

    2011-03-01

    resulted in a more robust cardiac differentiation than injection of ESC. Our data demonstrate that the model-system developed herein can be used to study the functional effects of candidate stem cells on the host myocardium, as well as to measure the residual activity of undifferentiated cells present in the mixture.

  10. The Sirt1 activator SRT3025 expands hematopoietic stem and progenitor cells and improves hematopoiesis in Fanconi anemia mice.

    PubMed

    Zhang, Qing-Shuo; Deater, Matthew; Schubert, Kathryn; Marquez-Loza, Laura; Pelz, Carl; Sinclair, David A; Grompe, Markus

    2015-07-01

    Fanconi anemia is a genetic bone marrow failure syndrome. The current treatment options are suboptimal and do not prevent the eventual onset of aplastic anemia requiring bone marrow transplantation. We previously showed that resveratrol, an antioxidant and an activator of the protein deacetylase Sirt1, enhanced hematopoiesis in Fancd2 mutant mice and improved the impaired stem cell quiescence observed in this disease. Given that Sirt1 is important for the function of hematopoietic stem cells, we hypothesized that Sirt1 activation may improve hematopoiesis. Indeed, Fancd2(-/-) mice and wild-type mice treated with the selective Sirt1 activator SRT3025 had increased numbers of hematopoietic stem and progenitor cells, platelets and white blood cells. SRT3025 was also protective against acetaldehyde-induced hematopoietic damage. Unlike resveratrol, however, SRT3025 did not affect stem cell quiescence, suggesting distinct mechanisms of action. Conditional deletion of Sirt1 in hematopoietic cells did not abrogate the beneficial effects of SRT3025, indicating that the drug did not act by directly stimulating Sirt1 in stem cells, but must be acting indirectly via extra-hematopoietic effects. RNA-Seq transcriptome analysis revealed the down-regulation of Egr1-p21 expression, providing a potential mechanism for improved hematopoiesis. Overall, our data indicate that SRT3025 or related compounds may be beneficial in Fanconi anemia and other bone marrow failure syndromes.

  11. PPARγ Is Activated during Congenital Cytomegalovirus Infection and Inhibits Neuronogenesis from Human Neural Stem Cells

    PubMed Central

    Rolland, Maude; Li, Xiaojun; Perez-Berezo, Teresa; Rauwel, Benjamin; Benchoua, Alexandra; Bessières, Bettina; Aziza, Jacqueline; Cenac, Nicolas; Luo, Minhua; Casper, Charlotte; Peschanski, Marc; Gonzalez-Dunia, Daniel; Leruez-Ville, Marianne; Davrinche, Christian; Chavanas, Stéphane

    2016-01-01

    Congenital infection by human cytomegalovirus (HCMV) is a leading cause of permanent sequelae of the central nervous system, including sensorineural deafness, cerebral palsies or devastating neurodevelopmental abnormalities (0.1% of all births). To gain insight on the impact of HCMV on neuronal development, we used both neural stem cells from human embryonic stem cells (NSC) and brain sections from infected fetuses and investigated the outcomes of infection on Peroxisome Proliferator-Activated Receptor gamma (PPARγ), a transcription factor critical in the developing brain. We observed that HCMV infection dramatically impaired the rate of neuronogenesis and strongly increased PPARγ levels and activity. Consistent with these findings, levels of 9-hydroxyoctadecadienoic acid (9-HODE), a known PPARγ agonist, were significantly increased in infected NSCs. Likewise, exposure of uninfected NSCs to 9-HODE recapitulated the effect of infection on PPARγ activity. It also increased the rate of cells expressing the IE antigen in HCMV-infected NSCs. Further, we demonstrated that (1) pharmacological activation of ectopically expressed PPARγ was sufficient to induce impaired neuronogenesis of uninfected NSCs, (2) treatment of uninfected NSCs with 9-HODE impaired NSC differentiation and (3) treatment of HCMV-infected NSCs with the PPARγ inhibitor T0070907 restored a normal rate of differentiation. The role of PPARγ in the disease phenotype was strongly supported by the immunodetection of nuclear PPARγ in brain germinative zones of congenitally infected fetuses (N = 20), but not in control samples. Altogether, our findings reveal a key role for PPARγ in neurogenesis and in the pathophysiology of HCMV congenital infection. They also pave the way to the identification of PPARγ gene targets in the infected brain. PMID:27078877

  12. Cancer Stem Cells: The Potential Targets of Chinese Medicines and Their Active Compounds

    PubMed Central

    Hong, Ming; Tan, Hor Yue; Li, Sha; Cheung, Fan; Wang, Ning; Nagamatsu, Tadashi; Feng, Yibin

    2016-01-01

    The pivotal role of cancer stem cells (CSCs) in the initiation and progression of malignancies has been rigorously validated, and the specific methods for identifying and isolating the CSCs from the parental cancer population have also been rapidly developed in recent years. This review aims to provide an overview of recent research progress of Chinese medicines (CMs) and their active compounds in inhibiting tumor progression by targeting CSCs. A great deal of CMs and their active compounds, such as Antrodia camphorate, berberine, resveratrol, and curcumin have been shown to regress CSCs, in terms of reversing drug resistance, inducing cell death and inhibiting cell proliferation as well as metastasis. Furthermore, one of the active compounds in coptis, berbamine may inhibit tumor progression by modulating microRNAs to regulate CSCs. The underlying molecular mechanisms and related signaling pathways involved in these processes were also discussed and concluded in this paper. Overall, the use of CMs and their active compounds may be a promising therapeutic strategy to eradicate cancer by targeting CSCs. However, further studies are needed to clarify the potential of clinical application of CMs and their active compounds as complementary and alternative therapy in this field. PMID:27338343

  13. Cancer Stem Cells: The Potential Targets of Chinese Medicines and Their Active Compounds.

    PubMed

    Hong, Ming; Tan, Hor Yue; Li, Sha; Cheung, Fan; Wang, Ning; Nagamatsu, Tadashi; Feng, Yibin

    2016-01-01

    The pivotal role of cancer stem cells (CSCs) in the initiation and progression of malignancies has been rigorously validated, and the specific methods for identifying and isolating the CSCs from the parental cancer population have also been rapidly developed in recent years. This review aims to provide an overview of recent research progress of Chinese medicines (CMs) and their active compounds in inhibiting tumor progression by targeting CSCs. A great deal of CMs and their active compounds, such as Antrodia camphorate, berberine, resveratrol, and curcumin have been shown to regress CSCs, in terms of reversing drug resistance, inducing cell death and inhibiting cell proliferation as well as metastasis. Furthermore, one of the active compounds in coptis, berbamine may inhibit tumor progression by modulating microRNAs to regulate CSCs. The underlying molecular mechanisms and related signaling pathways involved in these processes were also discussed and concluded in this paper. Overall, the use of CMs and their active compounds may be a promising therapeutic strategy to eradicate cancer by targeting CSCs. However, further studies are needed to clarify the potential of clinical application of CMs and their active compounds as complementary and alternative therapy in this field. PMID:27338343

  14. Remote Control of Intestinal Stem Cell Activity by Haemocytes in Drosophila

    PubMed Central

    Chakrabarti, Sveta; Li, Xiaoxue; Collas, Esther Jeanne; Boquete, Jean-Phillipe; Lemaitre, Bruno

    2016-01-01

    The JAK/STAT pathway is a key signaling pathway in the regulation of development and immunity in metazoans. In contrast to the multiple combinatorial JAK/STAT pathways in mammals, only one canonical JAK/STAT pathway exists in Drosophila. It is activated by three secreted proteins of the Unpaired family (Upd): Upd1, Upd2 and Upd3. Although many studies have established a link between JAK/STAT activation and tissue damage, the mode of activation and the precise function of this pathway in the Drosophila systemic immune response remain unclear. In this study, we used mutations in upd2 and upd3 to investigate the role of the JAK/STAT pathway in the systemic immune response. Our study shows that haemocytes express the three upd genes and that injury markedly induces the expression of upd3 by the JNK pathway in haemocytes, which in turn activates the JAK/STAT pathway in the fat body and the gut. Surprisingly, release of Upd3 from haemocytes upon injury can remotely stimulate stem cell proliferation and the expression of Drosomycin-like genes in the intestine. Our results also suggest that a certain level of intestinal epithelium renewal is required for optimal survival to septic injury. While haemocyte-derived Upd promotes intestinal stem cell activation and survival upon septic injury, haemocytes are dispensable for epithelium renewal upon oral bacterial infection. Our study also indicates that intestinal epithelium renewal is sensitive to insults from both the lumen and the haemocoel. It also reveals that release of Upds by haemocytes coordinates the wound-healing program in multiple tissues, including the gut, an organ whose integrity is critical to fly survival. PMID:27231872

  15. [Therapeutic use of stem cells. II. Adult stem cells].

    PubMed

    Uzan, Georges

    2004-09-30

    Many degenerative diseases are not curable by means of classical medicine. The long term objective of cell therapy is to treat the patients with their own stem cells that could be either purified from the diseased organ or from "reservoirs" of stem cells such as that constituted by the bone marrow. The existence of stem cells in the organs or reservoirs is now established in vitro and in some cases, in animal models. Numbers of technical problems linked to the scarcity of these cells still delay the clinical use of purified stem cells. However, clinical protocols using heterogeneous cell populations have already started to treat a growing number of diseases. In some case, autologous cells can be used, as it is the case for bone marrow transplantation in blood diseases. Mesenchymal cells, also purified from the bone marrow are currently used in orthopaedic diseases. Because these cells reveal a broad differentiation potential, active research programs explore their possible use for treatment of other diseases. Bone marrow also contains vascular stem cells that could be active in reappearing defective vessels responsible for ischaemic diseases. Indeed, clinical trials in which bone marrow cells are injected in the cardiac muscle of patients with myocardial infarction or in the leg muscle (gastrocnemius) of patients with hind limb ischaemia have already started. Artificial skin prepared from skin biopsies is used for the reconstitution of the derma of severely burned patients. Clinical trials have also started, using allogenic cells. The patients must be treated by immunosuppressive drugs. Neurodegenerative diseases such as Parkinson have been successfully treated by intra-cerebral injection of foetal neurones. Pancreatic islets implanted in the liver have shown to re-establish a normal glycaemia in diabetic patients. However, all these clinical trials use differentiated cells or at least progenitors which display differentiation potential and lifetime much more

  16. SMOOTH MUSCLE STEM CELLS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vascular smooth muscle cells (SMCs) originate from multiple types of progenitor cells. In the embryo, the most well-studied SMC progenitor is the cardiac neural crest stem cell. Smooth muscle differentiation in the neural crest lineage is controlled by a combination of cell intrinsic factors, includ...

  17. Activation of the amino acid response modulates lineage specification during differentiation of murine embryonic stem cells

    PubMed Central

    Shan, Jixiu; Hamazaki, Takashi; Tang, Tiffany A.; Terada, Naohiro

    2013-01-01

    In somatic cells, a collection of signaling pathways activated by amino acid limitation have been identified and referred to as the amino acid response (AAR). Despite the importance of possible detrimental effects of nutrient limitation during in vitro culture, the AAR has not been investigated in embryonic stem cells (ESC). AAR activation caused the expected increase in transcription factors that mediate specific AAR pathways, as well as the induction of asparagine synthetase, a terminal AAR target gene. Neither AAR activation nor stable knockdown of activating transcription factor (Atf) 4, a transcriptional mediator of the AAR, adversely affected ESC self-renewal or pluripotency. Low-level induction of the AAR over a 12-day period of embryoid body differentiation did alter lineage specification such that the primitive endodermal, visceral endodermal, and endodermal lineages were favored, whereas mesodermal and certain ectodermal lineages were suppressed. Knockdown of Atf4 further enhanced the AAR-induced increase in endodermal formation, suggesting that this phenomenon is mediated by an Atf4-independent mechanism. Collectively, the results indicate that, during differentiation of mouse embryoid bodies in culture, the availability of nutrients, such as amino acids, can influence the formation of specific cell lineages. PMID:23736538

  18. Neural stem cells secrete factors facilitating brain regeneration upon constitutive Raf-Erk activation

    PubMed Central

    Rhee, Yong-Hee; Yi, Sang-Hoon; Kim, Joo Yeon; Chang, Mi-Yoon; Jo, A-Young; Kim, Jinyoung; Park, Chang-Hwan; Cho, Je-Yoel; Choi, Young-Jin; Sun, Woong; Lee, Sang-Hun

    2016-01-01

    The intracellular Raf-Erk signaling pathway is activated during neural stem cell (NSC) proliferation, and neuronal and astrocytic differentiation. A key question is how this signal can evoke multiple and even opposing NSC behaviors. We show here, using a constitutively active Raf (ca-Raf), that Raf-Erk activation in NSCs induces neuronal differentiation in a cell-autonomous manner. By contrast, it causes NSC proliferation and the formation of astrocytes in an extrinsic autocrine/paracrine manner. Thus, treatment of NSCs with medium (CM) conditioned in ca-Raf-transduced NSCs (Raf-CM; RCM) became activated to form proliferating astrocytes resembling radial glial cells (RGCs) or adult-type NSCs. Infusion of Raf-CM into injured mouse brains caused expansion of the NSC population in the subventricular zone, followed by the formation of new neurons that migrated to the damaged site. Our study shows an example how molecular mechanisms dissecting NSC behaviors can be utilized to develop regenerative therapies in brain disorders. PMID:27554447

  19. Neural stem cells secrete factors facilitating brain regeneration upon constitutive Raf-Erk activation.

    PubMed

    Rhee, Yong-Hee; Yi, Sang-Hoon; Kim, Joo Yeon; Chang, Mi-Yoon; Jo, A-Young; Kim, Jinyoung; Park, Chang-Hwan; Cho, Je-Yoel; Choi, Young-Jin; Sun, Woong; Lee, Sang-Hun

    2016-01-01

    The intracellular Raf-Erk signaling pathway is activated during neural stem cell (NSC) proliferation, and neuronal and astrocytic differentiation. A key question is how this signal can evoke multiple and even opposing NSC behaviors. We show here, using a constitutively active Raf (ca-Raf), that Raf-Erk activation in NSCs induces neuronal differentiation in a cell-autonomous manner. By contrast, it causes NSC proliferation and the formation of astrocytes in an extrinsic autocrine/paracrine manner. Thus, treatment of NSCs with medium (CM) conditioned in ca-Raf-transduced NSCs (Raf-CM; RCM) became activated to form proliferating astrocytes resembling radial glial cells (RGCs) or adult-type NSCs. Infusion of Raf-CM into injured mouse brains caused expansion of the NSC population in the subventricular zone, followed by the formation of new neurons that migrated to the damaged site. Our study shows an example how molecular mechanisms dissecting NSC behaviors can be utilized to develop regenerative therapies in brain disorders. PMID:27554447

  20. Pluripotent stem cells reveal erythroid-specific activities of the GATA1 N-terminus

    PubMed Central

    Byrska-Bishop, Marta; VanDorn, Daniel; Campbell, Amy E.; Betensky, Marisol; Arca, Philip R.; Yao, Yu; Gadue, Paul; Costa, Fernando F.; Nemiroff, Richard L.; Blobel, Gerd A.; French, Deborah L.; Hardison, Ross C.; Weiss, Mitchell J.; Chou, Stella T.

    2015-01-01

    Germline GATA1 mutations that result in the production of an amino-truncated protein termed GATA1s (where s indicates short) cause congenital hypoplastic anemia. In patients with trisomy 21, similar somatic GATA1s-producing mutations promote transient myeloproliferative disease and acute megakaryoblastic leukemia. Here, we demonstrate that induced pluripotent stem cells (iPSCs) from patients with GATA1-truncating mutations exhibit impaired erythroid potential, but enhanced megakaryopoiesis and myelopoiesis, recapitulating the major phenotypes of the associated diseases. Similarly, in developmentally arrested GATA1-deficient murine megakaryocyte-erythroid progenitors derived from murine embryonic stem cells (ESCs), expression of GATA1s promoted megakaryopoiesis, but not erythropoiesis. Transcriptome analysis revealed a selective deficiency in the ability of GATA1s to activate erythroid-specific genes within populations of hematopoietic progenitors. Although its DNA-binding domain was intact, chromatin immunoprecipitation studies showed that GATA1s binding at specific erythroid regulatory regions was impaired, while binding at many nonerythroid sites, including megakaryocytic and myeloid target genes, was normal. Together, these observations indicate that lineage-specific GATA1 cofactor associations are essential for normal chromatin occupancy and provide mechanistic insights into how GATA1s mutations cause human disease. More broadly, our studies underscore the value of ESCs and iPSCs to recapitulate and study disease phenotypes. PMID:25621499

  1. Novel epigallocatechin gallate (EGCG) analogs activate AMP-activated protein kinase pathway and target cancer stem cells.

    PubMed

    Chen, Di; Pamu, Sreedhar; Cui, Qiuzhi; Chan, Tak Hang; Dou, Q Ping

    2012-05-01

    AMP-activated protein kinase (AMPK) is a critical monitor of cellular energy status and also controls processes related to tumor development, including cell cycle progression, protein synthesis, cell growth and survival. Therefore AMPK as an anti-cancer target has received intensive attention recently. It has been reported that the anti-diabetic drug metformin and some natural compounds, such as quercetin, genistein, capsaicin and green tea polyphenol epigallocatechin gallate (EGCG), can activate AMPK and inhibit cancer cell growth. Indeed, natural products have been the most productive source of leads for the development of anti-cancer drugs but perceived disadvantages, such as low bioavailability and week potency, have limited their development and use in the clinic. In this study we demonstrated that synthetic EGCG analogs 4 and 6 were more potent AMPK activators than metformin and EGCG. Activation of AMPK by these EGCG analogs resulted in inhibition of cell proliferation, up-regulation of the cyclin-dependent kinase inhibitor p21, down-regulation of mTOR pathway, and suppression of stem cell population in human breast cancer cells. Our findings suggest that novel potent and specific AMPK activators can be discovered from natural and synthetic sources that have potential to be used for anti-cancer therapy in the clinic. PMID:22459208

  2. Stem cells in cardiac repair.

    PubMed

    Henning, Robert J

    2011-01-01

    Myocardial infarction is the leading cause of death among people in industrialized nations. Although the heart has some ability to regenerate after infarction, myocardial restoration is inadequate. Consequently, investigators are currently exploring the use of human embryonic stem cells (hESCs), skeletal myoblasts and adult bone marrow stem cells to limit infarct size. hESCs are pluripotent cells that can regenerate myocardium in infarcted hearts, attenuate heart remodeling and contribute to left ventricle (LV) systolic force development. Since hESCs can form heart teratomas, investigators are differentiating hESCs toward cardiac progenitor cells prior to transplantation into hearts. Large quantities of hESCs cardiac progenitor cells, however, must be generated, immune rejection must be prevented and grafts must survive over the long term to significantly improve myocardial performance. Transplanted autologous skeletal myoblasts can survive in infarcted myocardium in small numbers, proliferate, differentiate into skeletal myofibers and increase the LV ejection fraction. These cells, however, do not form electromechanical connections with host cardiomyocytes. Consequently, electrical re-entry can occur and cause cardiac arrhythmias. Autologous bone marrow mononuclear cells contain hematopoietic and mesenchymal stem cells. In several meta-analyses, patients with coronary disease who received autologous bone marrow cells by intracoronary injection show significant 3.7% (range: 1.9-5.4%) increases in LV ejection fraction, decreases in LV end-systolic volume of -4.8 ml (range: -1.4 to -8.2 ml) and reductions in infarct size of 5.5% (-1.9 to -9.1%), without experiencing arrhythmias. Bone marrow cells appear to release biologically active factors that limit myocardial damage. Unfortunately, bone marrow cells from patients with chronic diseases propagate poorly and can die prematurely. Substantial challenges must be addressed and resolved to advance the use of stem cells

  3. EZH2 expands breast stem cells through activation of NOTCH1 signaling.

    PubMed

    Gonzalez, Maria E; Moore, Heather M; Li, Xin; Toy, Kathy A; Huang, Wei; Sabel, Michael S; Kidwell, Kelley M; Kleer, Celina G

    2014-02-25

    Breast cancer is the second-leading cause of cancer-related deaths in women, but the details of how it begins remain elusive. Increasing evidence supports the association of aggressive triple-negative (TN) breast cancer with heightened expression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) and increased tumor-initiating cells (TICs). However, mechanistic links between EZH2 and TICs are unclear, and direct demonstration of a tumorigenic function of EZH2 in vivo is lacking. Here, we identify an unrecognized EZH2/NOTCH1 axis that controls breast TICs in TN breast carcinomas. EZH2 overexpression increases NOTCH1 expression and signaling, and inhibition of NOTCH1 activity prevents EZH2-mediated stem cell expansion in nontumorigenic breast cells. We uncover a unique role of EZH2 in activating, rather than repressing, NOTCH1 signaling through binding to the NOTCH1 promoter in TN breast cancer cells. EZH2 binding is independent of its catalytic histone H3 lysine 27 methyltransferase activity and of the Polycomb Repressive Complex 2 but corresponds instead to transcriptional activation marks. In vivo, EZH2 knockdown decreases the onset and volume of xenografts derived from TN breast TICs. Conversely, transgenic EZH2 overexpression accelerates mammary tumor initiation and increases NOTCH1 activation in mouse mammary tumor virus-neu mice. Consonant with these findings, in clinical samples, high levels of EZH2 are significantly associated with activated NOTCH1 protein and increased TICs in TN invasive carcinomas. These data reveal a functional and mechanistic link between EZH2 levels, NOTCH1 signaling activation, and TICs, and provide previously unidentified evidence that EZH2 enhances breast cancer initiation. PMID:24516139

  4. EZH2 expands breast stem cells through activation of NOTCH1 signaling

    PubMed Central

    Gonzalez, Maria E.; Moore, Heather M.; Li, Xin; Toy, Kathy A.; Huang, Wei; Sabel, Michael S.; Kidwell, Kelley M.; Kleer, Celina G.

    2014-01-01

    Breast cancer is the second-leading cause of cancer-related deaths in women, but the details of how it begins remain elusive. Increasing evidence supports the association of aggressive triple-negative (TN) breast cancer with heightened expression of the Polycomb group protein Enhancer of Zeste Homolog 2 (EZH2) and increased tumor-initiating cells (TICs). However, mechanistic links between EZH2 and TICs are unclear, and direct demonstration of a tumorigenic function of EZH2 in vivo is lacking. Here, we identify an unrecognized EZH2/NOTCH1 axis that controls breast TICs in TN breast carcinomas. EZH2 overexpression increases NOTCH1 expression and signaling, and inhibition of NOTCH1 activity prevents EZH2-mediated stem cell expansion in nontumorigenic breast cells. We uncover a unique role of EZH2 in activating, rather than repressing, NOTCH1 signaling through binding to the NOTCH1 promoter in TN breast cancer cells. EZH2 binding is independent of its catalytic histone H3 lysine 27 methyltransferase activity and of the Polycomb Repressive Complex 2 but corresponds instead to transcriptional activation marks. In vivo, EZH2 knockdown decreases the onset and volume of xenografts derived from TN breast TICs. Conversely, transgenic EZH2 overexpression accelerates mammary tumor initiation and increases NOTCH1 activation in mouse mammary tumor virus-neu mice. Consonant with these findings, in clinical samples, high levels of EZH2 are significantly associated with activated NOTCH1 protein and increased TICs in TN invasive carcinomas. These data reveal a functional and mechanistic link between EZH2 levels, NOTCH1 signaling activation, and TICs, and provide previously unidentified evidence that EZH2 enhances breast cancer initiation. PMID:24516139

  5. Stem cell factor (SCF) protects osteoblasts from oxidative stress through activating c-Kit-Akt signaling

    SciTech Connect

    Yang, Lei; Wu, Zhong; Yin, Gang; Liu, Haifeng; Guan, Xiaojun; Zhao, Xiaoqiang; Wang, Jianguang; Zhu, Jianguo

    2014-12-12

    Highlights: • SCF receptor c-Kit is functionally expressed in primary and transformed osteoblasts. • SCF protects primary and transformed osteoblasts from H{sub 2}O{sub 2}. • SCF activation of c-Kit in osteoblasts, required for its cyto-protective effects. • c-Kit mediates SCF-induced Akt activation in cultured osteoblasts. • Akt activation is required for SCF-regulated cyto-protective effects in osteoblasts. - Abstract: Osteoblasts regulate bone formation and remodeling, and are main target cells of oxidative stress in the progression of osteonecrosis. The stem cell factor (SCF)-c-Kit pathway plays important roles in the proliferation, differentiation and survival in a range of cell types, but little is known about its functions in osteoblasts. In this study, we found that c-Kit is functionally expressed in both osteoblastic-like MC3T3-E1 cells and primary murine osteoblasts. Its ligand SCF exerted significant cyto-protective effects against hydrogen peroxide (H{sub 2}O{sub 2}). SCF activated its receptor c-Kit in osteoblasts, which was required for its cyto-protective effects against H{sub 2}O{sub 2}. Pharmacological inhibition (by Imatinib and Dasatinib) or shRNA-mediated knockdown of c-Kit thus inhibited SCF-mediated osteoblast protection. Further investigations showed that protection by SCF against H{sub 2}O{sub 2} was mediated via activation of c-Kit-dependent Akt pathway. Inhibition of Akt activation, through pharmacological or genetic means, suppressed SCF-mediated anti-H{sub 2}O{sub 2} activity in osteoblasts. In summary, we have identified a new SCF-c-Kit-Akt physiologic pathway that protects osteoblasts from H{sub 2}O{sub 2}-induced damages, and might minimize the risk of osteonecrosis caused by oxidative stress.

  6. ATF4 licenses C/EBPβ activity in human mesenchymal stem cells primed for adipogenesis.

    PubMed

    Cohen, Daniel M; Won, Kyoung-Jae; Nguyen, Nha; Lazar, Mitchell A; Chen, Christopher S; Steger, David J

    2015-01-01

    A well-established cascade of transcription factor (TF) activity orchestrates adipogenesis in response to chemical cues, yet how cell-intrinsic determinants of differentiation such as cell shape and/or seeding density inform this transcriptional program remain enigmatic. Here, we uncover a novel mechanism licensing transcription in human mesenchymal stem cells (hMSCs) adipogenically primed by confluence. Prior to adipogenesis, confluency promotes heterodimer recruitment of the bZip TFs C/EBPβ and ATF4 to a non-canonical C/EBP DNA sequence. ATF4 depletion decreases both cell-density-dependent transcription and adipocyte differentiation. Global profiling in hMSCs and a novel cell-free assay reveals that ATF4 requires C/EBPβ for genomic binding at a motif distinct from that bound by the C/EBPβ homodimer. Our observations demonstrate that C/EBPβ bridges the transcriptional programs in naïve, confluent cells and early differentiating pre-adipocytes. Moreover, they suggest that homo- and heterodimer formation poise C/EBPβ to execute diverse and stage-specific transcriptional programs by exploiting an expanded motif repertoire.

  7. Muscle stem cells at a glance

    PubMed Central

    Wang, Yu Xin; Dumont, Nicolas A.; Rudnicki, Michael A.

    2014-01-01

    ABSTRACT Muscle stem cells facilitate the long-term regenerative capacity of skeletal muscle. This self-renewing population of satellite cells has only recently been defined through genetic and transplantation experiments. Although muscle stem cells remain in a dormant quiescent state in uninjured muscle, they are poised to activate and produce committed progeny. Unlike committed myogenic progenitor cells, the self-renewal capacity gives muscle stem cells the ability to engraft as satellite cells and capitulate long-term regeneration. Similar to other adult stem cells, understanding the molecular regulation of muscle stem cells has significant implications towards the development of pharmacological or cell-based therapies for muscle disorders. This Cell Science at a Glance article and accompanying poster will review satellite cell characteristics and therapeutic potential, and provide an overview of the muscle stem cell hallmarks: quiescence, self-renewal and commitment. PMID:25300792

  8. Pancreatic stem cells remain unresolved.

    PubMed

    Jiang, Fang-Xu; Morahan, Grant

    2014-12-01

    Diabetes mellitus is caused by absolute (type 1) or relative (type 2) deficiency of insulin-secreting islet β cells. An ideal treatment of diabetes would, therefore, be to replace the lost or deficient β cells, by transplantation of donated islets or differentiated endocrine cells or by regeneration of endogenous islet cells. Due to their ability of unlimited proliferation and differentiation into all functional lineages in our body, including β cells, embryonic stem cells and induced pluripotent stem cells are ideally placed as cell sources for a diabetic transplantation therapy. Unfortunately, the inability to generate functional differentiated islet cells from pluripotent stem cells and the poor availability of donor islets have severely restricted the broad clinical use of the replacement therapy. Therefore, endogenous sources that can be directed to becoming insulin-secreting cells are actively sought after. In particular, any cell types in the developing or adult pancreas that may act as pancreatic stem cells (PSC) would provide an alternative renewable source for endogenous regeneration. In this review, we will summarize the latest progress and knowledge of such PSC, and discuss ways that facilitate the future development of this often controversial, but crucial research.

  9. Activated Wnt signaling induces myofibroblast differentiation of mesenchymal stem cells, contributing to pulmonary fibrosis.

    PubMed

    Sun, Zhaorui; Wang, Cong; Shi, Chaowen; Sun, Fangfang; Xu, Xiaomeng; Qian, Weiping; Nie, Shinan; Han, Xiaodong

    2014-05-01

    Acute lung injury may lead to fibrogenesis. However, no treatment is currently available. This study was conducted to determine the effects of bone marrow-derived mesenchymal stem cells (MSCs) in a model of HCl-induced acute lung injury in Sprague-Dawley (SD) rats. Stromal cell-derived factor (SDF)-1 and its receptor CXC chemokine receptor (CXCR)4 have been shown to participate in mobilizing MSCs. Adenovirus carrying the CXCR4 gene was used to transfect MSCs in order to increase the engraftment numbers of MSCs at injured sites. Histological examination data demonstrated that the engraftment of MSCs did not attenuate lung injury and pulmonary fibrosis. The results showed that engraftment of MSCs almost differentiated into myofibroblasts, but rarely differentiated into lung epithelial cells. Additionally, it was demonstrated that activated canonical Wnt/β-catenin signaling in injured lung tissue regulated the myofibroblast differentiation of MSCs in vivo. The in vitro study results demonstrated that activation of the Wnt/β-catenin signaling stimulated MSCs to express myofibroblast markers; however, this process was attenuated by Wnt antagonist DKK1. Therefore, the results demonstrated that the aberrant activation of Wnt signaling induces the myofibroblast differentiation of engrafted MSCs, thus contributing to pulmonary fibrosis following lung injury. PMID:24573542

  10. Controlled Osteogenic Differentiation of Mouse Mesenchymal Stem Cells by Tetracycline-Controlled Transcriptional Activation of Amelogenin.

    PubMed

    Wang, Fangfang; Okawa, Hiroko; Kamano, Yuya; Niibe, Kunimichi; Kayashima, Hiroki; Osathanon, Thanaphum; Pavasant, Prasit; Saeki, Makio; Yatani, Hirofumi; Egusa, Hiroshi

    2015-01-01

    Regenerative dental therapies for bone tissues rely on efficient targeting of endogenous and transplanted mesenchymal stem cells (MSCs) to guide bone formation. Amelogenin is the primary component of Emdogain, which is used to regenerate periodontal defects; however, the mechanisms underlying the therapeutic effects on alveolar bone remain unclear. The tetracycline (Tet)-dependent transcriptional regulatory system is a good candidate to investigate distinct roles of genes of interest during stem cell differentiation. Here, we investigated amelogenin-dependent regulation of osteogenesis in MSCs by establishing a Tet-controlled transcriptional activation system. Clonal mouse bone marrow-derived MSCs were lentivirally transduced with the Tet repressor (TetR) expression vector followed by drug selection to obtain MSCs constitutively expressing TetR (MSCs-TetR). Expression vectors that contained the Tet operator and amelogenin-coding (Amelx) cDNA fragments were constructed using the Gateway system and lentivirally introduced into MSCs-TetR to generate a Tet regulation system in MSCs (MSCs-TetR/Amelx). MSCs-TetR/Amelx significantly overexpressed the Amelx gene and protein in the presence of the tetracycline derivative doxycycline. Concomitant expression of osterix, bone sialoprotein (BSP), osteopontin, and osteocalcin was modulated by addition or removal of doxycycline under osteogenic guidance. During osteogenic induction, MSCs-TetR/Amelx treated with doxycycline showed significantly increased gene expression of osterix, type I collagen, BSP, and osteocalcin in addition to increased alkaline phosphatase activity and mineralized nodule formation. Enhanced extracellular matrix calcification was observed when forced Amelx expression commenced at the early stage but not at the intermediate or late stages of osteogenesis. These results suggest that a Tet-controlled Amelx gene regulation system for mouse MSCs was successfully established, in which transcriptional activation

  11. Fluorescent probes as a tool for cell population tracking in spontaneously active neural networks derived from human pluripotent stem cells.

    PubMed

    Mäkinen, M; Joki, T; Ylä-Outinen, L; Skottman, H; Narkilahti, S; Aänismaa, R

    2013-04-30

    Applications such as 3D cultures and tissue modelling require cell tracking with non-invasive methods. In this work, the suitability of two fluorescent probes, CellTracker, CT, and long chain carbocyanine dye, DiD, was investigated for long-term culturing of labeled human pluripotent stem cell-derived neural cells. We found that these dyes did not affect the cell viability. However, proliferation was decreased in DiD labeled cell population. With both dyes the labeling was stable up to 4 weeks. CT and DiD labeled cells could be co-cultured and, importantly, these mixed populations had their normal ability to form spontaneous electrical network activity. In conclusion, human neural cells can be successfully labeled with these two fluorescent probes without significantly affecting the cell characteristics. These labeled cells could be utilized further in e.g. building controlled neuronal networks for neurotoxicity screening platforms, combining cells with biomaterials for 3D studies, and graft development. PMID:23473797

  12. Single-Cell Transcriptomics Reveals a Population of Dormant Neural Stem Cells that Become Activated upon Brain Injury.

    PubMed

    Llorens-Bobadilla, Enric; Zhao, Sheng; Baser, Avni; Saiz-Castro, Gonzalo; Zwadlo, Klara; Martin-Villalba, Ana

    2015-09-01

    Heterogeneous pools of adult neural stem cells (NSCs) contribute to brain maintenance and regeneration after injury. The balance of NSC activation and quiescence, as well as the induction of lineage-specific transcription factors, may contribute to diversity of neuronal and glial fates. To identify molecular hallmarks governing these characteristics, we performed single-cell sequencing of an unbiased pool of adult subventricular zone NSCs. This analysis identified a discrete, dormant NSC subpopulation that already expresses distinct combinations of lineage-specific transcription factors during homeostasis. Dormant NSCs enter a primed-quiescent state before activation, which is accompanied by downregulation of glycolytic metabolism, Notch, and BMP signaling and a concomitant upregulation of lineage-specific transcription factors and protein synthesis. In response to brain ischemia, interferon gamma signaling induces dormant NSC subpopulations to enter the primed-quiescent state. This study unveils general principles underlying NSC activation and lineage priming and opens potential avenues for regenerative medicine in the brain. PMID:26235341

  13. Glycoside Hydrolase Activities in Cell Walls of Sclerenchyma Cells in the Inflorescence Stems of Arabidopsis thaliana Visualized in Situ.

    PubMed

    Banasiak, Alicja; Ibatullin, Farid M; Brumer, Harry; Mellerowicz, Ewa J

    2014-11-12

    Techniques for in situ localization of gene products provide indispensable information for understanding biological function. In the case of enzymes, biological function is directly related to activity, and therefore, knowledge of activity patterns is central to understanding the molecular controls of plant development. We have previously developed a novel type of fluorogenic substrate for revealing glycoside hydrolase activity in planta, based on resorufin β-glycosides Here, we explore a wider range of such substrates to visualize glycoside hydrolase activities in Arabidopsis inflorescence stems in real time, especially highlighting distinct distribution patterns of these activities in the secondary cell walls of sclerenchyma cells. The results demonstrate that β-1,4-glucosidase, β-1,4-glucanase and β-1,4-galactosidase activities accompany secondary wall deposition. In contrast, xyloglucanase activity follows a different pattern, with the highest signal observed in mature cells, concentrated in the middle lamella. These data further the understanding of the process of cell wall deposition and function in sclerenchymatic tissues of plants.

  14. Extinction models for cancer stem cell therapy

    PubMed Central

    Sehl, Mary; Zhou, Hua; Sinsheimer, Janet S.; Lange, Kenneth L.

    2012-01-01

    Cells with stem cell-like properties are now viewed as initiating and sustaining many cancers. This suggests that cancer can be cured by driving these cancer stem cells to extinction. The problem with this strategy is that ordinary stem cells are apt to be killed in the process. This paper sets bounds on the killing differential (difference between death rates of cancer stem cells and normal stem cells) that must exist for the survival of an adequate number of normal stem cells. Our main tools are birth–death Markov chains in continuous time. In this framework, we investigate the extinction times of cancer stem cells and normal stem cells. Application of extreme value theory from mathematical statistics yields an accurate asymptotic distribution and corresponding moments for both extinction times. We compare these distributions for the two cell populations as a function of the killing rates. Perhaps a more telling comparison involves the number of normal stem cells NH at the extinction time of the cancer stem cells. Conditioning on the asymptotic time to extinction of the cancer stem cells allows us to calculate the asymptotic mean and variance of NH. The full distribution of NH can be retrieved by the finite Fourier transform and, in some parameter regimes, by an eigenfunction expansion. Finally, we discuss the impact of quiescence (the resting state) on stem cell dynamics. Quiescence can act as a sanctuary for cancer stem cells and imperils the proposed therapy. We approach the complication of quiescence via multitype branching process models and stochastic simulation. Improvements to the τ-leaping method of stochastic simulation make it a versatile tool in this context. We conclude that the proposed therapy must target quiescent cancer stem cells as well as actively dividing cancer stem cells. The current cancer models demonstrate the virtue of attacking the same quantitative questions from a variety of modeling, mathematical, and computational perspectives

  15. Jumonji modulates polycomb activity and self-renewal versus differentiation of stem cells.

    PubMed

    Shen, Xiaohua; Kim, Woojin; Fujiwara, Yuko; Simon, Matthew D; Liu, Yingchun; Mysliwiec, Matthew R; Yuan, Guo-Cheng; Lee, Youngsook; Orkin, Stuart H

    2009-12-24

    Trimethylation on histone H3 lysine 27 (H3K27me3) by Polycomb repressive complex 2 (PRC2) regulates the balance between self-renewal and differentiation of embryonic stem cells (ESCs). The mechanisms controlling the activity and recruitment of PRC2 are largely unknown. Here we demonstrate that the founding member of the Jumonji family, JMJ (JUMONJI or JARID2), is associated with PRC2, colocalizes with PRC2 and H3K27me3 on chromatin, and modulates PRC2 function. In vitro JMJ inhibits PRC2 methyltransferase activity, consistent with increased H3K27me3 marks at PRC2 targets in Jmj(-/-) ESCs. Paradoxically, JMJ is required for efficient binding of PRC2, indicating that the interplay of PRC2 and JMJ fine-tunes deposition of the H3K27me3 mark. During differentiation, activation of genes marked by H3K27me3 and lineage commitments are delayed in Jmj(-/-) ESCs. Our results demonstrate that dynamic regulation of Polycomb complex activity orchestrated by JMJ balances self-renewal and differentiation, highlighting the involvement of chromatin dynamics in cell-fate transitions.

  16. [Stem cells and cancer].

    PubMed

    Arvelo, Francisco; Cotte, Carlos; Sojo, Felipe

    2014-12-01

    Surgery, radiotherapy and chemotherapy are universally recognized as the most effective anti-cancer therapies. Despite significant advances directed towards elucidating molecular mechanisms and developing clinical trials, cancer still remains a major public health issue. Cancer stem cells are a subpopulation of the cells that form the tumor. The discovery of these human cancer cells opens a perspective for understanding tumor recurrence, drug resistance and metastasis; and opens up new research directions on how cancer cells are capable of switching from dormancy to malignancy. Therapeutic alternatives emerge from a better understanding of the biology and the environment of tumor stem cells. The present paper aims to summarize the characteristics and properties of cancer stem cells, the ongoing research, as well as the best strategies for prevention and control of the mechanisms of tumor recurrence.

  17. Aneuploidy in stem cells

    PubMed Central

    Garcia-Martinez, Jorge; Bakker, Bjorn; Schukken, Klaske M; Simon, Judith E; Foijer, Floris

    2016-01-01

    Stem cells hold enormous promise for regenerative medicine as well as for engineering of model systems to study diseases and develop new drugs. The discovery of protocols that allow for generating induced pluripotent stem cells (IPSCs) from somatic cells has brought this promise steps closer to reality. However, as somatic cells might have accumulated various chromosomal abnormalities, including aneuploidies throughout their lives, the resulting IPSCs might no longer carry the perfect blueprint for the tissue to be generated, or worse, become at risk of adopting a malignant fate. In this review, we discuss the contribution of aneuploidy to healthy tissues and how aneuploidy can lead to disease. Furthermore, we review the differences between how somatic cells and stem cells respond to aneuploidy. PMID:27354891

  18. MEK1-independent activation of MAPK and MEK1-dependent activation of p70 S6 kinase by stem cell factor (SCF) in ovarian cancer cells

    SciTech Connect

    Liu, Lian; Zhang, Xin; Du, Chao; Zhang, Xiaoning; Hou, Nan; Zhao, Di; Sun, Jianzhi; Li, Li; Wang, Xiuwen; Ma, Chunhong

    2009-05-01

    We discovered a stem cell factor (SCF)-triggered, MEK1-independent, and PI3K-dependent MAPK activation pathway in the Kit-expressing ovarian cancer cell line HEY. When we knocked down MEK1 with RNA interference (RNAi) to study the function of MEK1 on the proliferation and survival of ovarian cancer cells, we found that impaired cell growth still occurred after MEK1 expression had been suppressed, although MAPK activation remained intact. This suggests that there is MEK1-independent activation of MAPK in the SCF-induced ovarian cancer cell growth process, and that MEK1 still plays a crucial role in maintaining the malignant properties of ovarian cancer cells even when it fails to activate MAPK as expected.

  19. Activated astrocytes enhance the dopaminergic differentiation of stem cells and promote brain repair through bFGF.

    PubMed

    Yang, Fan; Liu, Yunhui; Tu, Jie; Wan, Jun; Zhang, Jie; Wu, Bifeng; Chen, Shanping; Zhou, Jiawei; Mu, Yangling; Wang, Liping

    2014-12-17

    Astrocytes provide neuroprotective effects against degeneration of dopaminergic (DA) neurons and play a fundamental role in DA differentiation of neural stem cells. Here we show that light illumination of astrocytes expressing engineered channelrhodopsin variant (ChETA) can remarkably enhance the release of basic fibroblast growth factor (bFGF) and significantly promote the DA differentiation of human embryonic stem cells (hESCs) in vitro. Light activation of transplanted astrocytes in the substantia nigra (SN) also upregulates bFGF levels in vivo and promotes the regenerative effects of co-transplanted stem cells. Importantly, upregulation of bFGF levels, by specific light activation of endogenous astrocytes in the SN, enhances the DA differentiation of transplanted stem cells and promotes brain repair in a mouse model of Parkinson's disease (PD). Our study indicates that astrocyte-derived bFGF is required for regulation of DA differentiation of the stem cells and may provide a strategy targeting astrocytes for treatment of PD.

  20. Specification of haematopoietic stem cell fate via modulation of mitochondrial activity

    PubMed Central

    Vannini, Nicola; Girotra, Mukul; Naveiras, Olaia; Nikitin, Gennady; Campos, Vasco; Giger, Sonja; Roch, Aline; Auwerx, Johan; Lutolf, Matthias P.

    2016-01-01

    Haematopoietic stem cells (HSCs) differ from their committed progeny by relying primarily on anaerobic glycolysis rather than mitochondrial oxidative phosphorylation for energy production. However, whether this change in the metabolic program is the cause or the consequence of the unique function of HSCs remains unknown. Here we show that enforced modulation of energy metabolism impacts HSC self-renewal. Lowering the mitochondrial activity of HSCs by chemically uncoupling the electron transport chain drives self-renewal under culture conditions that normally induce rapid differentiation. We demonstrate that this metabolic specification of HSC fate occurs through the reversible decrease of mitochondrial mass by autophagy. Our data thus reveal a causal relationship between mitochondrial metabolism and fate choice of HSCs and also provide a valuable tool to expand HSCs outside of their native bone marrow niches. PMID:27731316

  1. Reinforcement of STAT3 activity reprogrammes human embryonic stem cells to naive-like pluripotency

    PubMed Central

    Chen, Hongwei; Aksoy, Irène; Gonnot, Fabrice; Osteil, Pierre; Aubry, Maxime; Hamela, Claire; Rognard, Cloé; Hochard, Arnaud; Voisin, Sophie; Fontaine, Emeline; Mure, Magali; Afanassieff, Marielle; Cleroux, Elouan; Guibert, Sylvain; Chen, Jiaxuan; Vallot, Céline; Acloque, Hervé; Genthon, Clémence; Donnadieu, Cécile; De Vos, John; Sanlaville, Damien; Guérin, Jean- François; Weber, Michael; Stanton, Lawrence W; Rougeulle, Claire; Pain, Bertrand; Bourillot, Pierre-Yves; Savatier, Pierre

    2015-01-01

    Leukemia inhibitory factor (LIF)/STAT3 signalling is a hallmark of naive pluripotency in rodent pluripotent stem cells (PSCs), whereas fibroblast growth factor (FGF)-2 and activin/nodal signalling is required to sustain self-renewal of human PSCs in a condition referred to as the primed state. It is unknown why LIF/STAT3 signalling alone fails to sustain pluripotency in human PSCs. Here we show that the forced expression of the hormone-dependent STAT3-ER (ER, ligand-binding domain of the human oestrogen receptor) in combination with 2i/LIF and tamoxifen allows human PSCs to escape from the primed state and enter a state characterized by the activation of STAT3 target genes and long-term self-renewal in FGF2- and feeder-free conditions. These cells acquire growth properties, a gene expression profile and an epigenetic landscape closer to those described in mouse naive PSCs. Together, these results show that temporarily increasing STAT3 activity is sufficient to reprogramme human PSCs to naive-like pluripotent cells. PMID:25968054

  2. A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration.

    PubMed

    Eap, Sandy; Keller, Laetitia; Schiavi, Jessica; Huck, Olivier; Jacomine, Leandro; Fioretti, Florence; Gauthier, Christian; Sebastian, Victor; Schwinté, Pascale; Benkirane-Jessel, Nadia

    2015-01-01

    New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone) nanofibrous implant (from 700 μm to 1 cm thick) was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII), 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days' implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7 therapeutic implant by adding human mesenchymal stem cells (hMSCs). The activity of this BMP-7-functionalized implant was again further enhanced by the addition of hMSCs to the implant (living materials), in vivo, as demonstrated by the analysis of new bone formation and calcification after 30 days' implantation in mice with calvaria defects. Therefore, implants functionalized with BMP-7 nanocontainers associated with hMSCs can act as an accelerator of in vivo bone mineralization and regeneration. PMID:25709432

  3. A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration

    PubMed Central

    Eap, Sandy; Keller, Laetitia; Schiavi, Jessica; Huck, Olivier; Jacomine, Leandro; Fioretti, Florence; Gauthier, Christian; Sebastian, Victor; Schwinté, Pascale; Benkirane-Jessel, Nadia

    2015-01-01

    New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone) nanofibrous implant (from 700 μm to 1 cm thick) was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII), 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days’ implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7 therapeutic implant by adding human mesenchymal stem cells (hMSCs). The activity of this BMP-7-functionalized implant was again further enhanced by the addition of hMSCs to the implant (living materials), in vivo, as demonstrated by the analysis of new bone formation and calcification after 30 days’ implantation in mice with calvaria defects. Therefore, implants functionalized with BMP-7 nanocontainers associated with hMSCs can act as an accelerator of in vivo bone mineralization and regeneration. PMID:25709432

  4. Lineage-specific enhancers activate self-renewal genes in macrophages and embryonic stem cells

    PubMed Central

    Soucie, Erinn L.; Weng, Ziming; Geirsdóttir, Laufey; Molawi, Kaaweh; Maurizio, Julien; Fenouil, Romain; Mossadegh-Keller, Noushine; Gimenez, Gregory; VanHille, Laurent; Beniazza, Meryam; Favret, Jeremy; Berruyer, Carole; Perrin, Pierre; Hacohen, Nir; Andrau, J.-C.; Ferrier, Pierre; Dubreuil, Patrice; Sidow, Arend; Sieweke, Michael H.

    2016-01-01

    Differentiated macrophages can self-renew in tissues and expand long-term in culture, but the gene regulatory mechanisms that accomplish self-renewal in the differentiated state have remained unknown. Here we show that in mice, the transcription factors MafB and c-Maf repress a macrophage-specific enhancer repertoire associated with a gene network controlling self-renewal. Single cell analysis revealed that, in vivo, proliferating resident macrophages can access this network by transient down-regulation of Maf transcription factors. The network also controls embryonic stem cell self-renewal but is associated with distinct embryonic stem cell-specific enhancers. This indicates that distinct lineage-specific enhancer platforms regulate a shared network of genes that control self-renewal potential in both stem and mature cells. PMID:26797145

  5. Lineage-specific enhancers activate self-renewal genes in macrophages and embryonic stem cells.

    PubMed

    Soucie, Erinn L; Weng, Ziming; Geirsdóttir, Laufey; Molawi, Kaaweh; Maurizio, Julien; Fenouil, Romain; Mossadegh-Keller, Noushine; Gimenez, Gregory; VanHille, Laurent; Beniazza, Meryam; Favret, Jeremy; Berruyer, Carole; Perrin, Pierre; Hacohen, Nir; Andrau, J-C; Ferrier, Pierre; Dubreuil, Patrice; Sidow, Arend; Sieweke, Michael H

    2016-02-12

    Differentiated macrophages can self-renew in tissues and expand long term in culture, but the gene regulatory mechanisms that accomplish self-renewal in the differentiated state have remained unknown. Here we show that in mice, the transcription factors MafB and c-Maf repress a macrophage-specific enhancer repertoire associated with a gene network that controls self-renewal. Single-cell analysis revealed that, in vivo, proliferating resident macrophages can access this network by transient down-regulation of Maf transcription factors. The network also controls embryonic stem cell self-renewal but is associated with distinct embryonic stem cell-specific enhancers. This indicates that distinct lineage-specific enhancer platforms regulate a shared network of genes that control self-renewal potential in both stem and mature cells.

  6. Combination Cell Therapy with Mesenchymal Stem Cells and Neural Stem Cells for Brain Stroke in Rats

    PubMed Central

    Hosseini, Seyed Mojtaba; Farahmandnia, Mohammad; Razi, Zahra; Delavari, Somayeh; Shakibajahromi, Benafsheh; Sarvestani, Fatemeh Sabet; Kazemi, Sepehr; Semsar, Maryam

    2015-01-01

    Objectives Brain stroke is the second most important events that lead to disability and morbidity these days. Although, stroke is important, there is no treatment for curing this problem. Nowadays, cell therapy has opened a new window for treating central nervous system disease. In some previous studies the Mesenchymal stem cells and neural stem cells. In this study, we have designed an experiment to assess the combination cell therapy (Mesenchymal and Neural stem cells) effects on brain stroke. Method and Materials The Mesenchymal stem cells were isolated from adult rat bone marrow and the neural stem cells were isolated from ganglion eminence of rat embryo 14 days. The Mesenchymal stem cells were injected 1 day after middle cerebral artery occlusion (MCAO) and the neural stem cells transplanted 7 day after MCAO. After 28 days, the neurological outcomes and brain lesion volumes were evaluated. Also, the activity of Caspase 3 was assessed in different groups. Result The group which received combination cell therapy had better neurological examination and less brain lesion. Also the combination cell therapy group had the least Caspase 3 activity among the groups. Conclusions The combination cell therapy is more effective than Mesenchymal stem cell therapy and neural stem cell therapy separately in treating the brain stroke in rats. PMID:26019759

  7. ROS activates JNK-mediated autophagy to counteract apoptosis in mouse mesenchymal stem cells in vitro

    PubMed Central

    Liu, Guan-yu; Jiang, Xiao-xue; Zhu, Xin; He, Wei-yang; Kuang, You-lin; Ren, Ke; Lin, Yong; Gou, Xin

    2015-01-01

    Aim: Transplantation of mesenchymal stem cells (MSCs) for the treatment of diabetic erectile dysfunction (ED) is hampered by apoptosis of the transplanted cells. In diabetic ED, there is increased oxidative stress and decreased NO in the corpora cavernosa, and reactive oxygen species (ROS) induce apoptosis of the transplanted cells. In this study we examined whether and how autophagy was involved in ROS-induced apoptosis of MSCs. Methods: Mouse C3H10 MSCs were treated with H2O2 to simulate the high oxidative condition in diabetic ED. Cell viability was measured using MTT assay. Apoptosis was analyzed by flow cytometry. Apoptosis- and autophagy-related proteins were detected with Western blot assays. Intracellular autophagosome accumulation was studied using transmission electron microscopy. Results: Treatment of MSCs with H2O2 (50–400 μmol/L) inhibited the cell viability in concentration- and time-dependent manners. Furthermore, H2O2 (300 μmol/L) induced apoptosis, as well as activated autophagy in MSCs. Pretreatment with lysosome inhibitor chloroquine (10 μmol/L) or PI3K inhibitor 3-methyladenine (5 mmol/L) significantly enhanced H2O2-induced cell death. Pretreatment with JNK inhibitor SP600125 (10 μmol/L) abrogated H2O2-induced accumulation of LC3-II, and attenuated H2O2-induced reduction of Bcl-2 levels in MSCs. Conclusion: ROS induce autophagy to counteract apoptosis in MSCs by activation of JNK. Thus, augmentation of autophagy may reduce apoptosis, prolonging MSC survival and improving MSC-based therapeutic efficacy for diabetic ED. PMID:26592514

  8. Sodium butyrate activates ERK to regulate differentiation of mesenchymal stem cells.

    PubMed

    Chen, Tain-Hsiung; Chen, Wei-Ming; Hsu, Ke-Hsun; Kuo, Cheng-Deng; Hung, Shih-Chieh

    2007-04-20

    Histone deacetylase inhibitors such as sodium butyrate are known to regulate the differentiation of a variety of cells. Mesenchymal stem cells (MSCs) differentiate into osteoblasts and adipocytes under transcriptional control of Runx2 and PPARgamma2, respectively. How these two transcription factors are regulated by sodium butyrate in order to specify the alternate cell fates remains a pivotal question. Sodium butyrate stimulated osteogenic differentiation and increased expression of Runx2 and genes regulated by Runx2 when cells were induced to undergo osteogenic differentiation. Sodium butyrate suppressed the adipogenic differentiation and decreased the expression of PPARgamma2 and LPL when MSCs were treated under conditions that promote adipogenic differentiation. Sodium butyrate also decreased the ratio of RANKL/OPG gene expression by MSCs. Analysis of MSCs induced in the presence of sodium butyrate revealed an immediate increase in ERK phosphorylation by sodium butyrate. The MEK-specific inhibitor, PD98059 but not p38- or JNK-specific inhibitor and the transfection with dominant negative ERK expressing plasmids blocked the sodium butyrate-induced regulation of MSC differentiation and increase in the RANKL/OPG ratio. Our results suggest that sodium butyrate modulates MSC differentiation and the RANKL/OPG ratio via activating ERK, and could be applied for in vivo bone growth using MSCs.

  9. Stem cell factor (SCF) can regulate the activation and expansion of murine intraepithelial lymphocytes.

    PubMed

    Wang, T; Langley, K E; Gourley, W K; Klimpel, G R

    2000-03-01

    Murine intraepithelial lymphocytes (IEL) express c-kit, the receptor for stem cell factor (SCF). SCF induced a low but significant proliferative response in IEL, but not in splenic T cells. SCF stimulation of IEL resulted in an expansion of the c-kit(+), TCRgammadelta(+)cell population. SCF-induced proliferation was dependent upon SCF-c-kit interactions, since antibody to c-kit blocked this response, and IEL obtained from c-kit mutant (W/W(v)) mice failed to respond to SCF. SCF acted synergistically with anti-TCRgammadelta and with concavalin A (Con A) to induce proliferation and interferon gamma (IFN-gamma) production in IEL. Finally, mice injected with SCF had a significant increase in the number of IEL in the small intestine. SCF-treated mice had increased numbers of TCRalphabeta(+)and TCRgammadelta(+)cell populations, as well as increased numbers of c-kit(+)and c-kit(-)IEL. These data suggest that SCF-c-kit interactions play an important role in regulating IEL expansion and activation.

  10. Dental pulp stem cells

    PubMed Central

    Ashri, Nahid Y.; Ajlan, Sumaiah A.; Aldahmash, Abdullah M.

    2015-01-01

    Inflammatory periodontal disease is a major cause of loss of tooth-supporting structures. Novel approaches for regeneration of periodontal apparatus is an area of intensive research. Periodontal tissue engineering implies the use of appropriate regenerative cells, delivered through a suitable scaffold, and guided through signaling molecules. Dental pulp stem cells have been used in an increasing number of studies in dental tissue engineering. Those cells show mesenchymal (stromal) stem cell-like properties including self-renewal and multilineage differentiation potentials, aside from their relative accessibility and pleasant handling properties. The purpose of this article is to review the biological principles of periodontal tissue engineering, along with the challenges facing the development of a consistent and clinically relevant tissue regeneration platform. This article includes an updated review on dental pulp stem cells and their applications in periodontal regeneration, in combination with different scaffolds and growth factors. PMID:26620980

  11. Compaction, Fusion, and Functional Activation of Three-Dimensional Human Mesenchymal Stem Cell Aggregate

    PubMed Central

    Tsai, Ang-Chen; Liu, Yijun; Yuan, Xuegang

    2015-01-01

    Human mesenchymal stem cells (hMSCs) are primary candidates in cell therapy and tissue engineering and are being tested in clinical trials for a wide range of diseases. Originally isolated and expanded as plastic adherent cells, hMSCs have intriguing properties of in vitro self-assembly into three-dimensional (3D) aggregates that improve a range of biological properties, including multilineage potential, secretion of therapeutic factors, and resistance against ischemic condition. While cell–cell contacts and cell–extracellular matrix interactions mediate 3D cell aggregation, the adaptive changes of hMSC cytoskeleton during self-assembly and associated metabolic reconfiguration may also influence aggregate properties and functional activation. In this study, we investigated the role of actin in regulating 3D hMSC aggregate compaction, fusion, spreading and functional activation. Individual hMSC aggregates with controlled initial cell number were formed by seeding a known number of hMSCs (500, 2000, and 5000 cells/well) in multi-well plates of an ultra-low adherent surface to form multicellular aggregates in individual wells. To assess the influence of actin-mediated contractility on hMSC aggregation and properties, actin modulators, including cytochalasin D (cytoD), nocodazole, lysophosphatidic acid (LPA), and Y-27632, were added at different stages of aggregation and their impacts on hMSC aggregate compaction and apoptosis were monitored. The results suggest that actin-mediated contractility influences hMSC aggregation, compaction, fusion, and spreading on adherent surface. Formation of multi-cellular aggregates significantly upregulated caspase 3/7 expression, expression of C-X-C chemokine receptor type 4 (CXCR-4), cell migration, secretion of prostaglandin E2 (PGE-2) and interleukin 6 (IL-6), and resistance to in vitro ischemic stress. The functional enhancement, however, is dependent on caspase activation, because treatment with Q-VD-OPh, a pan

  12. Reciprocal activation of prostate cancer cells and cancer-associated fibroblasts stimulates epithelial-mesenchymal transition and cancer stemness.

    PubMed

    Giannoni, Elisa; Bianchini, Francesca; Masieri, Lorenzo; Serni, Sergio; Torre, Eugenio; Calorini, Lido; Chiarugi, Paola

    2010-09-01

    Although cancer-associated fibroblasts (CAF) are key determinants in the malignant progression of cancer, their functional contribution to this process is still unclear. Analysis of the mutual interplay between prostate carcinoma cells and CAFs revealed a mandatory role of carcinoma-derived interleukin-6 in fibroblast activation. In turn, activated fibroblasts through secretion of metalloproteinases elicit in cancer cells a clear epithelial-mesenchymal transition (EMT), as well as enhancement of tumor growth and development of spontaneous metastases. CAF-induced EMT leads prostate carcinoma cells to enhance expression of stem cell markers, as well as the ability to form prostaspheres and to self-renew. Hence, the paracrine interplay between CAFs and cancer cells leads to an EMT-driven gain of cancer stem cell properties associated with aggressiveness and metastatic spread.

  13. DNA damage in stem cells activates p21, inhibits p53, and induces symmetric self-renewing divisions.

    PubMed

    Insinga, Alessandra; Cicalese, Angelo; Faretta, Mario; Gallo, Barbara; Albano, Luisa; Ronzoni, Simona; Furia, Laura; Viale, Andrea; Pelicci, Pier Giuseppe

    2013-03-01

    DNA damage leads to a halt in proliferation owing to apoptosis or senescence, which prevents transmission of DNA alterations. This cellular response depends on the tumor suppressor p53 and functions as a powerful barrier to tumor development. Adult stem cells are resistant to DNA damage-induced apoptosis or senescence, however, and how they execute this response and suppress tumorigenesis is unknown. We show that irradiation of hematopoietic and mammary stem cells up-regulates the cell cycle inhibitor p21, a known target of p53, which prevents p53 activation and inhibits p53 basal activity, impeding apoptosis and leading to cell cycle entry and symmetric self-renewing divisions. p21 also activates DNA repair, limiting DNA damage accumulation and self-renewal exhaustion. Stem cells with moderate DNA damage and diminished self-renewal persist after irradiation, however. These findings suggest that stem cells have evolved a unique, p21-dependent response to DNA damage that leads to their immediate expansion and limits their long-term survival.

  14. Cancer stem cell signaling pathways.

    PubMed

    Matsui, William H

    2016-09-01

    Tissue development and homeostasis are governed by the actions of stem cells. Multipotent cells are capable of self-renewal during the course of one's lifetime. The accurate and appropriate regulation of stem cell functions is absolutely critical for normal biological activity. Several key developmental or signaling pathways have been shown to play essential roles in this regulatory capacity. Specifically, the Janus-activated kinase/signal transducer and activator of transcription, Hedgehog, Wnt, Notch, phosphatidylinositol 3-kinase/phosphatase and tensin homolog, and nuclear factor-κB signaling pathways have all been shown experimentally to mediate various stem cell properties, such as self-renewal, cell fate decisions, survival, proliferation, and differentiation. Unsurprisingly, many of these crucial signaling pathways are dysregulated in cancer. Growing evidence suggests that overactive or abnormal signaling within and among these pathways may contribute to the survival of cancer stem cells (CSCs). CSCs are a relatively rare population of cancer cells capable of self-renewal, differentiation, and generation of serially transplantable heterogeneous tumors of several types of cancer. PMID:27611937

  15. The Src homology 2 protein Shb promotes cell cycle progression in murine hematopoietic stem cells by regulation of focal adhesion kinase activity

    SciTech Connect

    Gustafsson, Karin; Heffner, Garrett; Wenzel, Pamela L.; Curran, Matthew; Grawé, Jan; McKinney-Freeman, Shannon L.; Daley, George Q.; Welsh, Michael

    2013-07-15

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shb deficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time. -- Highlights: • Shb is an adaptor protein operating downstream of tyrosine kinase receptors. • Shb deficiency reduces hematopoietic stem cell proliferation. • The proliferative effect of Shb occurs via increased

  16. High ALDH Activity Identifies Chemotherapy-Resistant Ewing's Sarcoma Stem Cells That Retain Sensitivity to EWS-FLI1 Inhibition

    PubMed Central

    Gul, Naheed; Katuri, Varalakshmi; O'Neill, Alison; Kong, Yali; Brown, Milton L.; Toretsky, Jeffrey A.; Loeb, David M.

    2010-01-01

    Background Cancer stem cells are a chemotherapy-resistant population capable of self-renewal and of regenerating the bulk tumor, thereby causing relapse and patient death. Ewing's sarcoma, the second most common form of bone tumor in adolescents and young adults, follows a clinical pattern consistent with the Cancer Stem Cell model – remission is easily achieved, even for patients with metastatic disease, but relapse remains frequent and is usually fatal. Methodology/Principal Findings We have isolated a subpopulation of Ewing's sarcoma cells, from both human cell lines and human xenografts grown in immune deficient mice, which express high aldehyde dehydrogenase (ALDHhigh) activity and are enriched for clonogenicity, sphere-formation, and tumor initiation. The ALDHhigh cells are resistant to chemotherapy in vitro, but this can be overcome by the ATP binding cassette transport protein inhibitor, verapamil. Importantly, these cells are not resistant to YK-4-279, a small molecule inhibitor of EWS-FLI1 that is selectively toxic to Ewing's sarcoma cells both in vitro and in vivo. Conclusions/Significance Ewing's sarcoma contains an ALDHhigh stem-like population of chemotherapy-resistant cells that retain sensitivity to EWS-FLI1 inhibition. Inhibiting the EWS-FLI1 oncoprotein may prove to be an effective means of improving patient outcomes by targeting Ewing's sarcoma stem cells that survive standard chemotherapy. PMID:21085683

  17. Mitochondrial aerobic respiration is activated during hair follicle stem cell differentiation, and its dysfunction retards hair regeneration.

    PubMed

    Tang, Yan; Luo, Binping; Deng, Zhili; Wang, Ben; Liu, Fangfen; Li, Jinmao; Shi, Wei; Xie, Hongfu; Hu, Xingwang; Li, Ji

    2016-01-01

    Background. Emerging research revealed the essential role of mitochondria in regulating stem/progenitor cell differentiation of neural progenitor cells, mesenchymal stem cells and other stem cells through reactive oxygen species (ROS), Notch or other signaling pathway. Inhibition of mitochondrial protein synthesis results in hair loss upon injury. However, alteration of mitochondrial morphology and metabolic function during hair follicle stem cells (HFSCs) differentiation and how they affect hair regeneration has not been elaborated upon. Methods. We compared the difference in mitochondrial morphology and activity between telogen bulge cells and anagen matrix cells. Expression levels of mitochondrial ROS and superoxide dismutase 2 (SOD2) were measured to evaluate redox balance. In addition, the level of pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase (PDH) were estimated to present the change in energetic metabolism during differentiation. To explore the effect of the mitochondrial metabolism on regulating hair regeneration, hair growth was observed after application of a mitochondrial respiratory inhibitor upon hair plucking. Results. During HFSCs differentiation, mitochondria became elongated with more abundant organized cristae and showed higher activity in differentiated cells. SOD2 was enhanced for redox balance with relatively stable ROS levels in differentiated cells. PDK increased in HFSCs while differentiated cells showed enhanced PDH, indicating that respiration switched from glycolysis to oxidative phosphorylation during differentiation. Inhibiting mitochondrial respiration in differentiated hair follicle cells upon hair plucking repressed hair regeneration in vivo. Conclusions. Upon HFSCs differentiation, mitochondria are elongated with more abundant cristae and show higher activity, accompanying with activated aerobic respiration in differentiated cells for higher energy supply. Also, dysfunction of mitochondrial respiration delays hair

  18. Mitochondrial aerobic respiration is activated during hair follicle stem cell differentiation, and its dysfunction retards hair regeneration

    PubMed Central

    Tang, Yan; Luo, Binping; Deng, Zhili; Wang, Ben; Liu, Fangfen; Li, Jinmao; Shi, Wei; Xie, Hongfu; Hu, Xingwang

    2016-01-01

    Background. Emerging research revealed the essential role of mitochondria in regulating stem/progenitor cell differentiation of neural progenitor cells, mesenchymal stem cells and other stem cells through reactive oxygen species (ROS), Notch or other signaling pathway. Inhibition of mitochondrial protein synthesis results in hair loss upon injury. However, alteration of mitochondrial morphology and metabolic function during hair follicle stem cells (HFSCs) differentiation and how they affect hair regeneration has not been elaborated upon. Methods. We compared the difference in mitochondrial morphology and activity between telogen bulge cells and anagen matrix cells. Expression levels of mitochondrial ROS and superoxide dismutase 2 (SOD2) were measured to evaluate redox balance. In addition, the level of pyruvate dehydrogenase kinase (PDK) and pyruvate dehydrogenase (PDH) were estimated to present the change in energetic metabolism during differentiation. To explore the effect of the mitochondrial metabolism on regulating hair regeneration, hair growth was observed after application of a mitochondrial respiratory inhibitor upon hair plucking. Results. During HFSCs differentiation, mitochondria became elongated with more abundant organized cristae and showed higher activity in differentiated cells. SOD2 was enhanced for redox balance with relatively stable ROS levels in differentiated cells. PDK increased in HFSCs while differentiated cells showed enhanced PDH, indicating that respiration switched from glycolysis to oxidative phosphorylation during differentiation. Inhibiting mitochondrial respiration in differentiated hair follicle cells upon hair plucking repressed hair regeneration in vivo. Conclusions. Upon HFSCs differentiation, mitochondria are elongated with more abundant cristae and show higher activity, accompanying with activated aerobic respiration in differentiated cells for higher energy supply. Also, dysfunction of mitochondrial respiration delays hair

  19. Stem cells in microfluidics

    PubMed Central

    Wu, Huei-Wen; Lin, Chun-Che; Lee, Gwo-Bin

    2011-01-01

    Microfluidic techniques have been recently developed for cell-based assays. In microfluidic systems, the objective is for these microenvironments to mimic in vivo surroundings. With advantageous characteristics such as optical transparency and the capability for automating protocols, different types of cells can be cultured, screened, and monitored in real time to systematically investigate their morphology and functions under well-controlled microenvironments in response to various stimuli. Recently, the study of stem cells using microfluidic platforms has attracted considerable interest. Even though stem cells have been studied extensively using bench-top systems, an understanding of their behavior in in vivo-like microenvironments which stimulate cell proliferation and differentiation is still lacking. In this paper, recent cell studies using microfluidic systems are first introduced. The various miniature systems for cell culture, sorting and isolation, and stimulation are then systematically reviewed. The main focus of this review is on papers published in recent years studying stem cells by using microfluidic technology. This review aims to provide experts in microfluidics an overview of various microfluidic systems for stem cell research. PMID:21522491

  20. Evidence for ovarian granulosa stem cells: telomerase activity and localization of the telomerase ribonucleic acid component in bovine ovarian follicles.

    PubMed

    Lavranos, T C; Mathis, J M; Latham, S E; Kalionis, B; Shay, J W; Rodgers, R J

    1999-08-01

    We have previously postulated that granulosa cells of developing follicles arise from a population of stem cells. Stem cells and cancer cells can divide indefinitely partly because they express telomerase. Telomerase is a ribonucleoprotein enzyme that repairs the ends of telomeres that otherwise shorten progressively upon each successive cell division. In this study we carried out cell cycle analyses and examined telomerase expression to examine our hypothesis. Preantral (60-100 microm) and small (1 mm) follicles, as well as granulosa cells from medium-sized (3 mm) and large (6-8 mm) follicles, were isolated. Cell cycle analyses and expression of Ki-67, a cell cycle-related protein, were undertaken on follicles of each size (n = 3) by flow cytometry; 12% to 16% of granulosa cells in all follicles were in the S phase, and less than 2% were in the G(2)/M phase. Telomerase activity (n = 3) was highest in the small preantral follicles, declining at the 1-mm stage and even further at the 3-mm stage. In situ hybridization histochemistry was carried out on bovine ovaries, and telomerase RNA was detected in the granulosa cells of growing follicles but not primordial follicles. Two major patterns of staining were observed in the membrana granulosa of antral follicles: staining in the middle and antral layers, and staining in the middle and basal layers. No staining was detected in oocytes. Our results strongly support our hypothesis that granulosa cells arise from a population of stem cells. PMID:10411512

  1. Stem Cell Research

    SciTech Connect

    Verfaillie, Catherine

    2009-01-23

    We have identified a population of primitive cells in normal human post-natal bone marrow that can, at the single cell level, differentiate in many ways and also proliferate extensively. These cells can differentiate in vitro into most mesodermal cell types (for example, bone cells, and others), as well as cells into cells of the nervous system. The finding that stem cells exist in post-natal tissues with previously unknown proliferation and differentiation potential opens up the possibility of using them to treat a host of degenerative, traumatic or congenital diseases.

  2. Stem Cell Research

    SciTech Connect

    Verfaillie, Catherine

    2002-01-23

    We have identified a population of primitive cells in normal human post-natal bone marrow that can, at the single cell level, differentiate in many ways and also proliferate extensively. These cells can differentiate in vitro into most mesodermal cell types (for example, bone cells, and others), as well as cells into cells of the nervous system. The finding that stem cells exist in post-natal tissues with previously unknown proliferation and differentiation potential opens up the possibility of using them to treat a host of degenerative, traumatic or congenital diseases.

  3. Catalyzing stem cell research.

    PubMed

    Willemse, Lisa; Lyall, Drew; Rudnicki, Michael

    2008-09-01

    In 2001, the Stem Cell Network was the first of its kind, a bold initiative to forge and nurture pan-Canadian collaborations involving researchers, engineers, clinicians and private and public sector partners. Canada's broad and deep pool of stem cell talent proved to be a fertile ground for such an initiative, giving rise to a strong, thriving network that, 7 years later, can list innovative cell expansion and screening technologies, early-phase clinical trials for stroke, pulmonary hypertension, muscular dystrophy and cornea replacement, and leading discourse on ethical, legal and social issues among its accomplishments. As it moves into its second and final phase of funding, the Stem Cell Network continues to push boundaries and has set its sights on overcoming the obstacles that impede the transfer of research findings to clinical applications, commercial products and public policy. PMID:18729799

  4. Catalyzing stem cell research.

    PubMed

    Willemse, Lisa; Lyall, Drew; Rudnicki, Michael

    2008-09-01

    In 2001, the Stem Cell Network was the first of its kind, a bold initiative to forge and nurture pan-Canadian collaborations involving researchers, engineers, clinicians and private and public sector partners. Canada's broad and deep pool of stem cell talent proved to be a fertile ground for such an initiative, giving rise to a strong, thriving network that, 7 years later, can list innovative cell expansion and screening technologies, early-phase clinical trials for stroke, pulmonary hypertension, muscular dystrophy and cornea replacement, and leading discourse on ethical, legal and social issues among its accomplishments. As it moves into its second and final phase of funding, the Stem Cell Network continues to push boundaries and has set its sights on overcoming the obstacles that impede the transfer of research findings to clinical applications, commercial products and public policy.

  5. Human Embryonic Stem Cells have Constitutively Active Bax at the Golgi and are Primed to Undergo Rapid Apoptosis

    PubMed Central

    Dumitru, Raluca; Gama, Vivian; Fagan, B. Matthew; Bower, Jacquelyn J.; Swahari, Vijay; Pevny, Larysa H.; Deshmukh, Mohanish

    2012-01-01

    Human embryonic stem (hES) cells activate a rapid apoptotic response after DNA damage but the underlying mechanisms are unknown. A critical mediator of apoptosis is Bax, which is reported to become active and translocate to the mitochondria only after apoptotic stimuli. Here we show that undifferentiated hES cells constitutively maintain Bax in its active conformation. Surprisingly, active Bax was maintained at the Golgi rather than at the mitochondria, thus allowing hES cells to effectively minimize the risks associated with having pre-activated Bax. After DNA damage, active Bax rapidly translocated to the mitochondria by a p53-dependent mechanism. Interestingly, upon differentiation, Bax was no longer active and cells were not acutely sensitive to DNA damage. Thus, maintenance of Bax in its active form is a unique mechanism that can prime hES cells for rapid death, likely to prevent the propagation of mutations during the early critical stages of embryonic development. PMID:22560721

  6. Adult Stem Cell Responses to Nanostimuli

    PubMed Central

    Tsimbouri, Penelope M.

    2015-01-01

    Adult or mesenchymal stem cells (MSCs) have been found in different tissues in the body, residing in stem cell microenvironments called “stem cell niches”. They play different roles but their main activity is to maintain tissue homeostasis and repair throughout the lifetime of an organism. Their ability to differentiate into different cell types makes them an ideal tool to study tissue development and to use them in cell-based therapies. This differentiation process is subject to both internal and external forces at the nanoscale level and this response of stem cells to nanostimuli is the focus of this review. PMID:26193326

  7. UV-activated 7-dehydrocholesterol-coated titanium implants promote differentiation of human umbilical cord mesenchymal stem cells into osteoblasts.

    PubMed

    Satué, María; Ramis, Joana M; Monjo, Marta

    2016-01-01

    Vitamin D metabolites are essential for bone regeneration and mineral homeostasis. The vitamin D precursor 7-dehydrocholesterol can be used after UV irradiation to locally produce active vitamin D by osteoblastic cells. Furthermore, UV-irradiated 7-dehydrocholesterol is a biocompatible coating for titanium implants with positive effects on osteoblast differentiation. In this study, we examined the impact of titanium implants surfaces coated with UV-irradiated 7-dehydrocholesterol on the osteogenic differentiation of human umbilical cord mesenchymal stem cells. First, the synthesis of cholecalciferol (D3) was achieved through the incubation of the UV-activated 7-dehydrocholesterol coating for 48 h at 23℃. Further, we investigated in vitro the biocompatibility of this coating in human umbilical cord mesenchymal stem cells and its potential to enhance their differentiation towards the osteogenic lineage. Human umbilical cord mesenchymal stem cells cultured onto UV-irradiated 7-dehydrocholesterol-coated titanium implants surfaces, combined with osteogenic supplements, upregulated the gene expression of several osteogenic markers and showed higher alkaline phosphatase activity and calcein blue staining, suggesting increased mineralization. Thus, our results show that the use of UV irradiation on 7-dehydrocholesterol -treated titanium implants surfaces generates a bioactive coating that promotes the osteogenic differentiation of human umbilical cord mesenchymal stem cells, with regenerative potential for improving osseointegration in titanium-based bone anchored implants.

  8. Osteogenic activity of bone marrow-derived mesenchymal stem cells (BMSCs) seeded on irradiated allogenic bone.

    PubMed

    Tohma, Yasuaki; Dohi, Yoshiko; Ohgushi, Hajime; Tadokoro, Mika; Akahane, Manabu; Tanaka, Yasuhito

    2012-02-01

    Allogenic bone grafting, a technique used in orthopaedic surgery, has several problems, including low osteogenic activity. To overcome the problem, this study aimed to determine whether in vivo osteogenesis could be enhanced using allogenic irradiated bone grafts after seeding with autologous bone marrow-derived mesenchymal stem cells (BMSCs). The allogenic bone cylinders were extracted from ACI rats and sterilized by irradiation. Donor BMSCs were obtained from fresh Fischer 344 (F344) rat bone marrow by cell culture. The allogenic bone with or without BMSCs were transplanted subcutaneously into syngeneic F344 rats. At 4 weeks after transplantation, high alkaline phosphatase (ALP) activity, bone-specific osteocalcin mRNA expression and newly formed bone were detected in the allogenic bone with BMSCs. The origin of the newly formed bone was derived from cultured donor BMSCs. However, none of these identifiers of osteogenesis were detected in either the fresh or the irradiated allogenic bone without BMSCs. These results indicate the availability of autologous BMSCs to heighten the osteogenic response of allogenic bone. Our present tissue-engineering method might contribute to a wide variety of allogenic bone grafting techniques in clinical settings.

  9. Optimizing cardiac repair and regeneration through activation of the endogenous cardiac stem cell compartment.

    PubMed

    Ellison, Georgina M; Nadal-Ginard, Bernardo; Torella, Daniele

    2012-10-01

    Given the aging of the Western World and declining death rates due to acute coronary syndromes, the increasing trends in the magnitude and morbidity of heart failure (HF) are predicted to continue for the foreseeable future. It is imperative to develop effective therapies for the amelioration and prevention of HF. The search for the best cell type to be used in clinical protocols of cardiac regeneration is still on. That the adult mammalian heart harbors endogenous, multipotent cardiac stem/progenitor cells (eCSCs) and that cardiomyocytes are replaced throughout adulthood represent a paradigm shift in cardiovascular biology. The presence of eCSCs supports the view that the heart can repair itself if the eCSCs can be properly stimulated. Pending a better understanding of eCSC biology, it should be possible to replace autologous cell transplantation-based myocardial regeneration protocols with an "off-the-shelf," readily available, and effective regenerative/reparative therapy based on activation of the eCSCs in situ. PMID:22688972

  10. Notch and Wnt/β-catenin signaling pathway play important roles in activating liver cancer stem cells

    PubMed Central

    Wang, Ronghua; Sun, Qian; Wang, Peng; Liu, Man; Xiong, Si; Luo, Jing; Huang, Hai; Du, Qiang; Geller, David A.; Cheng, Bin

    2016-01-01

    Human hepatocellular carcinoma (HCC) is driven and maintained by liver cancer stem cells (LCSCs) that display stem cell properties. These LCSCs are promoted by the intersecting of Notch and Wnt/β-Catenin signaling pathways. In this study, we demonstrate that LCSCs with markers CD90, CD24, CD13, and CD133 possess stem properties of self-renewal and tumorigenicity in NOD/SCID mice. The increased expression of these markers was correlated with advanced disease stage, larger tumors, and worse overall survival in 61 HCC cases. We also found that both Notch and Wnt/β-catenin signaling pathways played important roles in increasing the stem-ness characteristics of LCSCs. Our data suggested that Notch1 was downstream of Wnt/β-catenin. The active form of Notch1 intracellular domain (NICD) expression depended on Wnt/β-catenin pathway activation. Moreover, Notch1 negatively contributed to Wnt/β-catenin signaling modulation. Knock down of Notch1 with lentivirus N1ShRNA up-regulated the active form of β-catenin. Ectopic expression of NICD with LV-Notch1 in LCSCs attenuated β-catenin/TCF dependent luciferase activity significantly. In addition, there was a non-proteasome mediated feedback loop between Notch1 and Wnt/β-catenin signaling in LCSCs. The central role of Notch and the Wnt/β-catenin signaling pathway in LCSCs may provide an attractive therapeutic strategy against HCC. PMID:26735577

  11. Changing Factors associated with Parent Activation after Pediatric Hematopoietic Stem Cell Transplant

    PubMed Central

    Pennarola, Brian W.; Rodday, Angie Mae; Bingen, Kristin; Schwartz, Lisa A.; Patel, Sunita K.; Syrjala, Karen L.; Mayer, Deborah K.; Ratichek, Sara J.; Guinan, Eva C.; Kupst, Mary Jo; Hibbard, Judith H.; Parsons, Susan K.

    2015-01-01

    Purpose To identify factors associated with parent activation in parents of children undergoing pediatric hematopoietic stem cell transplant (HSCT) in the 6 months following HSCT, and to address if their association with parent activation changes over time. Methods Measures for this analysis, including the Parent Patient Activation Measure (Parent-PAM), were completed by parents (N=198) prior to their child’s HSCT preparative regimen and again at 6 months post-HSCT. Clinical data were also collected. A repeated measures model was built to estimate the association between clinical and demographic factors and parent well-being on Parent-PAM scores. Interactions with time were considered to test for changing effects over time. Results Throughout the HSCT course, older parent age was associated with lower Parent-PAM scores (β=−0.29, p=0.02) and never being married was associated with higher scores (versus married, β=12.27, p=0.03). While higher parent emotional functioning scores were not associated with activation at baseline, they were important at 6 months (baseline: β=−0.002, p=0.96; interaction: β=0.14, p=0.03). At baseline longer duration of illness was associated with increased activation, but this effect diminished with time (baseline: β=3.29, p=0.0002; interaction: β=−2.40, p=0.02). Activation levels dropped for parents of children who went from private to public insurance (baseline: β=2.95, p=0.53; interaction: β=−13.82, p=0.004). Clinical events did not affect Parent-PAM scores. Conclusions Our findings reveal important changes in the factors associated with parent activation in the first 6 months after pediatric HSCT. These findings may reflect the emotional and financial toll of pediatric HSCT on parent activation. PMID:25519755

  12. Calpain-Mediated positional information directs cell wall orientation to sustain plant stem cell activity, growth and development

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eukaryotic development and stem cell control depend on the integration of cell positional sensing with cell cycle control and cell wall positioning, yet few factors that directly link these events are known. The DEFECTIVE KERNEL1 (DEK1) gene encoding the unique plant calpain protein is fundamental f...

  13. IGF1 stimulates crypt expansion via differential activation of 2 intestinal stem cell populations.

    PubMed

    Van Landeghem, Laurianne; Santoro, M Agostina; Mah, Amanda T; Krebs, Adrienne E; Dehmer, Jeffrey J; McNaughton, Kirk K; Helmrath, Michael A; Magness, Scott T; Lund, P Kay

    2015-07-01

    Insulin-like growth factor 1 (IGF1) has potent trophic effects on normal or injured intestinal epithelium, but specific effects on intestinal stem cells (ISCs) are undefined. We used Sox9-enhanced green fluorescent protein (EGFP) reporter mice that permit analyses of both actively cycling ISCs (Sox9-EGFP(Low)) and reserve/facultative ISCs (Sox9-EGFP(High)) to study IGF1 action on ISCs in normal intestine or during crypt regeneration after high-dose radiation-induced injury. We hypothesized that IGF1 differentially regulates proliferation and gene expression in actively cycling and reserve/facultative ISCs. IGF1 was delivered for 5 days using subcutaneously implanted mini-pumps in uninjured mice or after 14 Gy abdominal radiation. ISC numbers, proliferation, and transcriptome were assessed. IGF1 increased epithelial growth in nonirradiated mice and enhanced crypt regeneration after radiation. In uninjured and regenerating intestines, IGF1 increased total numbers of Sox9-EGFP(Low) ISCs and percentage of these cells in M-phase. IGF1 increased percentages of Sox9-EGFP(High) ISCs in S-phase but did not expand this population. Microarray revealed that IGF1 activated distinct gene expression signatures in the 2 Sox9-EGFP ISC populations. In vitro IGF1 enhanced enteroid formation by Sox9-EGFP(High) facultative ISCs but not Sox9-EGFP(Low) actively cycling ISCs. Our data provide new evidence that IGF1 activates 2 ISC populations via distinct regulatory pathways to promote growth of normal intestinal epithelium and crypt regeneration after irradiation.

  14. Chemotherapy targeting cancer stem cells.

    PubMed

    Liu, Haiguang; Lv, Lin; Yang, Kai

    2015-01-01

    Conventional chemotherapy is the main treatment for cancer and benefits patients in the form of decreased relapse and metastasis and longer overall survival. However, as the target therapy drugs and delivery systems are not wholly precise, it also results in quite a few side effects, and is less efficient in many cancers due to the spared cancer stem cells, which are considered the reason for chemotherapy resistance, relapse, and metastasis. Conventional chemotherapy limitations and the cancer stem cell hypothesis inspired our search for a novel chemotherapy targeting cancer stem cells. In this review, we summarize cancer stem cell enrichment methods, the search for new efficient drugs, and the delivery of drugs targeting cancer stem cells. We also discuss cancer stem cell hierarchy complexity and the corresponding combination therapy for both cancer stem and non-stem cells. Learning from cancer stem cells may reveal novel strategies for chemotherapy in the future.

  15. Chemotherapy targeting cancer stem cells

    PubMed Central

    Liu, Haiguang; Lv, Lin; Yang, Kai

    2015-01-01

    Conventional chemotherapy is the main treatment for cancer and benefits patients in the form of decreased relapse and metastasis and longer overall survival. However, as the target therapy drugs and delivery systems are not wholly precise, it also results in quite a few side effects, and is less efficient in many cancers due to the spared cancer stem cells, which are considered the reason for chemotherapy resistance, relapse, and metastasis. Conventional chemotherapy limitations and the cancer stem cell hypothesis inspired our search for a novel chemotherapy targeting cancer stem cells. In this review, we summarize cancer stem cell enrichment methods, the search for new efficient drugs, and the delivery of drugs targeting cancer stem cells. We also discuss cancer stem cell hierarchy complexity and the corresponding combination therapy for both cancer stem and non-stem cells. Learning from cancer stem cells may reveal novel strategies for chemotherapy in the future. PMID:26045975

  16. Implementation of structured physical activity in the pediatric stem cell transplantation.

    PubMed

    Rosenhagen, A; Bernhörster, M; Vogt, L; Weiss, B; Senn, A; Arndt, S; Siegler, K; Jung, M; Bader, P; Banzer, W

    2011-05-01

    The peripheral blood stem cell transplantation (PBSCT) represents a specific, but stressful therapy for hemato-oncological diseases. While for adults, data suggest positive eff ects for a supportive sport therapy, this question is not evaluated sufficiently for children. The objective of this study was to examine the integration of sports activity into pediatric PBSCT and to indicate attainable results. This 2-step case-control-study included 23 children and adolescents from the PBSCT: During the isolation phase 13 patients trained 3 times per week on a cycle ergometer and passed a course with different sports equipment. Apart from recording physiologic adaptations, quality of live was inquired in a pre-post design using questionnaires. Guided interviews according to necessity and requirements for sports activity at the PBSCT unit completed the evaluation and were used for the intervention as well as for the control group (n = 10) without sports therapy. On the ergometer, patients trained average 25 min with 0.6 watt / kg. In the majority, a loss of muscular power could be avoided. Quality of life and fatigue symptoms improved by trend. Interview analysis showed general acceptance of physical activity during PBSCT. After initial skepticism due to the additional burden, our implementation study showed the feasibility of supportive sports therapy in PBSCT. Quality and flexibility of the equipment should be higher than normal and different physical and psychological conditions of the patients should be anticipated and integrated into the training program.

  17. Modulation of Adult Mesenchymal Stem Cells Activity by Toll-Like Receptors: Implications on Therapeutic Potential

    PubMed Central

    DelaRosa, Olga; Lombardo, Eleuterio

    2010-01-01

    Mesenchymal stem cells (MSCs) are of special interest as therapeutic agents in the settings of both chronic inflammatory and autoimmune diseases. Toll-like receptors (TLR) ligands have been linked with the perpetuation of inflammation in a number of chronic inflammatory diseases due to the permanent exposure of the immune system to TLR-specific stimuli. Therefore, MSCs employed in therapy can be potentially exposed to TLR ligands, which may modulate MSC therapeutic potential in vivo. Recent results demonstrate that MSCs are activated by TLR ligands leading to modulation of the differentiation, migration, proliferation, survival, and immunosuppression capacities. However inconsistent results among authors have been reported suggesting that the source of MSCs, TLR stimuli employed or culture conditions play a role. Notably, activation by TLR ligands has not been reported to modulate the “immunoprivileged” phenotype of MSCs which is of special relevance regarding the use of allogeneic MSC-based therapies. In this review, we discuss the available data on the modulation of MSCs activity through TLR signalling. PMID:20628526

  18. Wnt Signaling in Cancer Stem Cell Biology.

    PubMed

    de Sousa E Melo, Felipe; Vermeulen, Louis

    2016-06-27

    Aberrant regulation of Wnt signaling is a common theme seen across many tumor types. Decades of research have unraveled the epigenetic and genetic alterations that result in elevated Wnt pathway activity. More recently, it has become apparent that Wnt signaling levels identify stem-like tumor cells that are responsible for fueling tumor growth. As therapeutic targeting of these tumor stem cells is an intense area of investigation, a concise understanding on how Wnt activity relates to cancer stem cell traits is needed. This review attempts at summarizing the intricacies between Wnt signaling and cancer stem cell biology with a special emphasis on colorectal cancer.

  19. Wnt Signaling in Cancer Stem Cell Biology

    PubMed Central

    de Sousa e Melo, Felipe; Vermeulen, Louis

    2016-01-01

    Aberrant regulation of Wnt signaling is a common theme seen across many tumor types. Decades of research have unraveled the epigenetic and genetic alterations that result in elevated Wnt pathway activity. More recently, it has become apparent that Wnt signaling levels identify stem-like tumor cells that are responsible for fueling tumor growth. As therapeutic targeting of these tumor stem cells is an intense area of investigation, a concise understanding on how Wnt activity relates to cancer stem cell traits is needed. This review attempts at summarizing the intricacies between Wnt signaling and cancer stem cell biology with a special emphasis on colorectal cancer. PMID:27355964

  20. Stomach development, stem cells and disease.

    PubMed

    Kim, Tae-Hee; Shivdasani, Ramesh A

    2016-02-15

    The stomach, an organ derived from foregut endoderm, secretes acid and enzymes and plays a key role in digestion. During development, mesenchymal-epithelial interactions drive stomach specification, patterning, differentiation and growth through selected signaling pathways and transcription factors. After birth, the gastric epithelium is maintained by the activity of stem cells. Developmental signals are aberrantly activated and stem cell functions are disrupted in gastric cancer and other disorders. Therefore, a better understanding of stomach development and stem cells can inform approaches to treating these conditions. This Review highlights the molecular mechanisms of stomach development and discusses recent findings regarding stomach stem cells and organoid cultures, and their roles in investigating disease mechanisms.

  1. EphB and Ephrin-B Interactions Mediate Human Mesenchymal Stem Cell Suppression of Activated T-Cells

    PubMed Central

    Nguyen, Thao M.; Arthur, Agnes; Hayball, John D.

    2013-01-01

    Mesenchymal stromal/stem cells (MSC) express the contact-dependent erythropoietin-producing hepatocellular (Eph) receptor tyrosine kinase family and their cognate ephrin ligands, which are known to regulate thymocyte maturation and selection, T-cell transendothelial migration, activation, co-stimulation, and proliferation. However, the contribution of Eph/ephrin molecules in mediating human MSC suppression of activated T-cells remains to be determined. In the present study, we showed that EphB2 and ephrin-B2 are expressed by ex vivo expanded MSC, while the corresponding ligands, ephrin-B1 and EphB4, respectively, are highly expressed by T-cells. Initial studies demonstrated that EphB2-Fc and ephrin-B2-Fc molecules suppressed T-cell proliferation in allogeneic mixed lymphocyte reaction (MLR) assays compared with human IgG-treated controls. While the addition of a third-party MSC population demonstrated dramatic suppression of T-cell proliferation responses in the MLR, blocking the function of EphB2 or EphB4 receptors using inhibitor binding peptides significantly increased T-cell proliferation. Consistent with these observations, shRNA EphB2 or ephrin-B2 knockdown expression in MSC reduced their ability to inhibit T-cell proliferation. Importantly, the expression of immunosuppressive factors, indoleamine 2, 3-dioxygenase, transforming growth factor-β1, and inducible nitric oxide synthase expressed by MSC, was up-regulated after stimulation with EphB4 and ephrin-B1 in the presence of interferon (IFN)-γ, compared with untreated controls. Conversely, key factors involved in T-cell activation and proliferation, such as interleukin (IL)-2, IFN-γ, tumor necrosis factor-α, and IL-17, were down-regulated by T-cells treated with EphB2 or ephrin-B2 compared with untreated controls. Studies utilizing signaling inhibitors revealed that inhibition of T-cell proliferation is partly mediated through EphB2-induced ephrin-B1 reverse signaling or ephrin-B2-mediated EphB4 forward

  2. Humoral Activity of Cord Blood-Derived Stem/Progenitor Cells: Implications for Stem Cell-Based Adjuvant Therapy of Neurodegenerative Disorders

    PubMed Central

    Paczkowska, Edyta; Kaczyńska, Katarzyna; Pius-Sadowska, Ewa; Rogińska, Dorota; Kawa, Miłosz; Ustianowski, Przemysław; Safranow, Krzysztof; Celewicz, Zbigniew; Machaliński, Bogusław

    2013-01-01

    Background Stem/progenitor cells (SPCs) demonstrate neuro-regenerative potential that is dependent upon their humoral activity by producing various trophic factors regulating cell migration, growth, and differentiation. Herein, we compared the expression of neurotrophins (NTs) and their receptors in specific umbilical cord blood (UCB) SPC populations, including lineage-negative, CD34+, and CD133+ cells, with that in unsorted, nucleated cells (NCs). Methods and Results The expression of NTs and their receptors was detected by QRT-PCR, western blotting, and immunofluorescent staining in UCB-derived SPC populations (i.e., NCs vs. lineage-negative, CD34+, and CD133+ cells). To better characterize, global gene expression profiles of SPCs were determined using genome-wide RNA microarray technology. Furthermore, the intracellular production of crucial neuro-regenerative NTs (i.e., BDNF and NT-3) was assessed in NCs and lineage-negative cells after incubation for 24, 48, and 72 h in both serum and serum-free conditions. We discovered significantly higher expression of NTs and NT receptors at both the mRNA and protein level in lineage-negative, CD34+, and CD133+ cells than in NCs. Global gene expression analysis revealed considerably higher expression of genes associated with the production and secretion of proteins, migration, proliferation, and differentiation in lineage-negative cells than in CD34+ or CD133+ cell populations. Notably, after short-term incubation under serum-free conditions, lineage-negative cells and NCs produced significantly higher amounts of BDNF and NT-3 than under steady-state conditions. Finally, conditioned medium (CM) from lineage-negative SPCs exerted a beneficial impact on neural cell survival and proliferation. Conclusions Collectively, our findings demonstrate that UCB-derived SPCs highly express NTs and their relevant receptors under steady-state conditions, NT expression is greater under stress-related conditions and that CM from SPCs

  3. Stem cells in the nervous system.

    PubMed

    Maldonado-Soto, Angel R; Oakley, Derek H; Wichterle, Hynek; Stein, Joel; Doetsch, Fiona K; Henderson, Christopher E

    2014-11-01

    Given their capacity to regenerate cells lost through injury or disease, stem cells offer new vistas into possible treatments for degenerative diseases and their underlying causes. As such, stem cell biology is emerging as a driving force behind many studies in regenerative medicine. This review focuses on the current understanding of the applications of stem cells in treating ailments of the human brain, with an emphasis on neurodegenerative diseases. Two types of neural stem cells are discussed: endogenous neural stem cells residing within the adult brain and pluripotent stem cells capable of forming neural cells in culture. Endogenous neural stem cells give rise to neurons throughout life, but they are restricted to specialized regions in the brain. Elucidating the molecular mechanisms regulating these cells is key in determining their therapeutic potential as well as finding mechanisms to activate dormant stem cells outside these specialized microdomains. In parallel, patient-derived stem cells can be used to generate neural cells in culture, providing new tools for disease modeling, drug testing, and cell-based therapies. Turning these technologies into viable treatments will require the integration of basic science with clinical skills in rehabilitation.

  4. Stem Cells in the Nervous System

    PubMed Central

    Maldonado-Soto, Angel R.; Oakley, Derek H.; Wichterle, Hynek; Stein, Joel; Doetsch, Fiona K.; Henderson, Christopher E.

    2014-01-01

    Given their capacity to regenerate cells lost through injury or disease, stem cells offer new vistas into possible treatments for degenerative diseases and their underlying causes. As such, stem cell biology is emerging as a driving force behind many studies in the field of regenerative medicine. This review focuses on our current understanding of the applications of stem cells in treating ailments of the human brain, with an emphasis on neurodegenerative diseases. Two types of neural stem cells are discussed: endogenous neural stem cells residing within the adult brain, and pluripotent stem cells capable of forming neural cells in culture. Endogenous neural stem cells give rise to neurons throughout life, but they are restricted to specialized regions in the brain. Elucidating the molecular mechanisms regulating these cells is key in determining their therapeutic potential, as well as finding mechanisms to activate dormant stem cells outside of these specialized microdomains. In parallel, patient-derived stem cells can be used to generate neural cells in culture, providing new tools for disease modeling, drug testing and cell-based therapies. Turning these technologies into viable treatments will require the integration of basic science with clinical skills in rehabilitation. PMID:24800720

  5. Inhibiting Notch Activity in Breast Cancer Stem Cells by Glucose Functionalized Nanoparticles Carrying γ-secretase Inhibitors

    PubMed Central

    Mamaeva, Veronika; Niemi, Rasmus; Beck, Michaela; Özliseli, Ezgi; Desai, Diti; Landor, Sebastian; Gronroos, Tove; Kronqvist, Pauliina; Pettersen, Ina K N; McCormack, Emmet; Rosenholm, Jessica M; Linden, Mika; Sahlgren, Cecilia

    2016-01-01

    Cancer stem cells (CSCs) are a challenge in cancer treatment due to their therapy resistance. We demonstrated that enhanced Notch signaling in breast cancer promotes self-renewal of CSCs that display high glycolytic activity and aggressive hormone-independent tumor growth in vivo. We took advantage of the glycolytic phenotype and the dependence on Notch activity of the CSCs and designed nanoparticles to target the CSCs. Mesoporous silica nanoparticles were functionalized with glucose moieties and loaded with a γ-secretase inhibitor, a potent interceptor of Notch signaling. Cancer cells and CSCs in vitro and in vivo efficiently internalized these particles, and particle uptake correlated with the glycolytic profile of the cells. Nanoparticle treatment of breast cancer transplants on chick embryo chorioallantoic membranes efficiently reduced the cancer stem cell population of the tumor. Our data reveal that specific CSC characteristics can be utilized in nanoparticle design to improve CSC-targeted drug delivery and therapy. PMID:26916284

  6. Direct Mechanical Stimulation of Stem Cells: A Beating Electromechanically Active Scaffold for Cardiac Tissue Engineering.

    PubMed

    Gelmi, Amy; Cieslar-Pobuda, Artur; de Muinck, Ebo; Los, Marek; Rafat, Mehrdad; Jager, Edwin W H

    2016-06-01

    The combination of stem cell therapy with a supportive scaffold is a promising approach to improving cardiac tissue engineering. Stem cell therapy can be used to repair nonfunctioning heart tissue and achieve myocardial regeneration, and scaffold materials can be utilized in order to successfully deliver and support stem cells in vivo. Current research describes passive scaffold materials; here an electroactive scaffold that provides electrical, mechanical, and topographical cues to induced human pluripotent stem cells (iPS) is presented. The poly(lactic-co-glycolic acid) fiber scaffold coated with conductive polymer polypyrrole (PPy) is capable of delivering direct electrical and mechanical stimulation to the iPS. The electroactive scaffolds demonstrate no cytotoxic effects on the iPS as well as an increased expression of cardiac markers for both stimulated and unstimulated protocols. This study demonstrates the first application of PPy as a supportive electroactive material for iPS and the first development of a fiber scaffold capable of dynamic mechanical actuation.

  7. Redox Disrupting Potential of ToxCast™Chemicals Ranked by Activity in Mouse Embryonic Stem Cells

    EPA Science Inventory

    Little is known regarding the adverse outcome pathways responsible for developmental toxicity following exposure to chemicals. An evaluation of Toxoast™ Phase I chemicals in an adherent mouse embryonic stem cell (mESC) assay revealed a redox sensitive pathway that correlated with...

  8. REDOX DISRUPTING POTENTIAL OF TOXCAST CHEMICALS RANKED BY ACTIVITY IN MOUSE EMBRYONIC STEM CELLS

    EPA Science Inventory

    To gain insight regarding the adverse outcome pathways leading to developmental toxicity following exposure to chemicals, we evaluated ToxCast™ Phase I chemicals in an adherent mouse embryonic stem cell (mESC) assay and identified a redox sensitive pathway that correlated with al...

  9. Stem cells and transplant arteriosclerosis.

    PubMed

    Xu, Qingbo

    2008-05-01

    Stem cells can differentiate into a variety of cells to replace dead cells or to repair damaged tissues. Recent evidence indicates that stem cells are involved in the pathogenesis of transplant arteriosclerosis, an alloimmune initiated vascular stenosis that often results in transplant organ failure. Although the pathogenesis of transplant arteriosclerosis is not yet fully understood, recent developments in stem cell research have suggested novel mechanisms of vascular remodeling in allografts. For example, stem cells derived from the recipient may repair damaged endothelial cells of arteries in transplant organs. Further evidence suggests that stem cells or endothelial progenitor cells may be released from both bone marrow and non-bone marrow tissues. Vascular stem cells appear to replenish cells that died in donor vessels. Concomitantly, stem/progenitor cells may also accumulate in the intima, where they differentiate into smooth muscle cells. However, several issues concerning the contribution of stem cells to the pathogenesis of transplant arteriosclerosis are controversial, eg, whether bone marrow-derived stem cells can differentiate into smooth muscle cells that form neointimal lesions of the vessel wall. This review summarizes recent research on the role of stem cells in transplant arteriosclerosis, discusses the mechanisms of stem cell homing and differentiation into mature endothelial and smooth muscle cells, and highlights the controversial issues in the field.

  10. Laser biomodulation on stem cells

    NASA Astrophysics Data System (ADS)

    Liu, Timon C.; Duan, Rui; Li, Yan; Li, Xue-Feng; Tan, Li-Ling; Liu, Songhao

    2001-08-01

    Stem cells are views from the perspectives of their function, evolution, development, and cause. Counterintuitively, most stem cells may arise late in development, to act principally in tissue renewal, thus ensuring an organisms long-term survival. Surprisingly, recent reports suggest that tissue-specific adult stem cells have the potential to contribute to replenishment of multiple adult tissues. Stem cells are currently in the news for two reasons: the successful cultivation of human embryonic stem cell lines and reports that adult stem cells can differentiate into developmentally unrelated cell types, such as nerve cells into blood cells. The spotlight on stem cells has revealed gaps in our knowledge that must be filled if we are to take advantage of their full potential for treating devastating degenerative diseases such as Parkinsons's disease and muscular dystrophy. We need to know more about the intrinsic controls that keep stem cells as stem cells or direct them along particular differentiation pathways. Such intrinsic regulators are, in turn, sensitive to the influences of the microenvironment, or niche, where stem cells normally reside. Both intrinsic and extrinsic signals regular stem cell fate and some of these signals have now been identified. Vacek et al and Wang et al have studied the effect of low intensity laser on the haemopoietic stem cells in vitro. There experiments show there is indeed the effect of low intensity laser on the haemopoietic stem cells in vitro, and the present effect is the promotion of haemopoietic stem cells proliferation. In other words, low intensity laser irradiation can act as an extrinsic signal regulating stem cell fate. In this paper, we study how low intensity laser can be used to regulate stem cell fate from the viewpoint of collective phototransduction.

  11. Myocardial regeneration by activation of multipotent cardiac stem cells in ischemic heart failure

    NASA Astrophysics Data System (ADS)

    Urbanek, Konrad; Torella, Daniele; Sheikh, Farooq; de Angelis, Antonella; Nurzynska, Daria; Silvestri, Furio; Beltrami, C. Alberto; Bussani, Rossana; Beltrami, Antonio P.; Quaini, Federico; Bolli, Roberto; Leri, Annarosa; Kajstura, Jan; Anversa, Piero

    2005-06-01

    In this study, we tested whether the human heart possesses a cardiac stem cell (CSC) pool that promotes regeneration after infarction. For this purpose, CSC growth and senescence were measured in 20 hearts with acute infarcts, 20 hearts with end-stage postinfarction cardiomyopathy, and 12 control hearts. CSC number increased markedly in acute and, to a lesser extent, in chronic infarcts. CSC growth correlated with the increase in telomerase-competent dividing CSCs from 1.5% in controls to 28% in acute infarcts and 14% in chronic infarcts. The CSC mitotic index increased 29-fold in acute and 14-fold in chronic infarcts. CSCs committed to the myocyte, smooth muscle, and endothelial cell lineages increased 85-fold in acute infarcts and 25-fold in chronic infarcts. However, p16INK4a-p53-positive senescent CSCs also increased and were 10%, 18%, and 40% in controls, acute infarcts, and chronic infarcts, respectively. Old CSCs had short telomeres and apoptosis involved 0.3%, 3.8%, and 9.6% of CSCs in controls, acute infarcts, and chronic infarcts, respectively. These variables reduced the number of functionally competent CSCs from 26,000/cm3 of viable myocardium in acute to 7,000/cm3 in chronic infarcts, respectively. In seven acute infarcts, foci of spontaneous myocardial regeneration that did not involve cell fusion were identified. In conclusion, the human heart possesses a CSC compartment, and CSC activation occurs in response to ischemic injury. The loss of functionally competent CSCs in chronic ischemic cardiomyopathy may underlie the progressive functional deterioration and the onset of terminal failure. cardiac progenitor cells | human heart | myocardial infarction

  12. Activation of Wnt3a signaling promotes myogenic differentiation of mesenchymal stem cells in mdx mice

    PubMed Central

    Shang, Yan-chang; Wang, Shu-hui; Xiong, Fu; Peng, Fu-ning; Liu, Zhen-shan; Geng, Jia; Zhang, Cheng

    2016-01-01

    Aim: Duchenne muscular dystrophy (DMD) is an X-linked genetic muscular disorder with no effective treatment at present. Mesenchymal stem cell (MSC) transplantation has been used to treat DMD, but the efficiency is low. Our previous studies show that activation of Wnt3a signaling promotes myogenic differentiation of MSCs in vitro. Here we report an effective MSC transplantation therapy in mdx mice by activation of Wnt3a signaling. Methods: MSCs were isolated from mouse bone marrow, and pretreated with Wnt3a-conditioned medium (Wnt3a-CM), then transplanted into mdx mice. The recipient mice were euthanized at 4, 8, 12, 16 weeks after the transplantation, and muscle pathological changes were examined. The expression of dystrophin in muscle was detected using immunofluorescence staining, RT-PCR and Western blotting. Results: Sixteen weeks later, transplantation of Wnt3a-pretreated MSCs in mdx mice improved the characteristics of dystrophic muscles evidenced by significant reductions in centrally nucleated myofibers, the variability range of cross-sectional area (CSA) and the connective tissue area of myofibers. Furthermore, transplantation of Wnt3a-pretreated MSCs in mdx mice gradually and markedly increased the expression of dystrophin in muscle, and improved the efficiency of myogenic differentiation. Conclusion: Transplantation of Wnt3a-pretreated MSCs in mdx mice results in long-term amelioration of the dystrophic phenotype and restores dystrophin expression in muscle. The results suggest that Wnt3a may be a promising candidate for the treatment of DMD. PMID:27133298

  13. Great expectations: private sector activity in tissue engineering, regenerative medicine, and stem cell therapeutics.

    PubMed

    Lysaght, Michael J; Jaklenec, Ana; Deweerd, Elizabeth

    2008-02-01

    This report draws upon data from a variety of sources to provide a detailed estimate of the current scope of private sector development and commercial activity in the aggregate field comprising tissue engineering, regenerative medicine, and stem cell therapeutics. Economic activity has grown a remarkable fivefold in the past 5 years. As of mid-2007 approximately 50 firms or business units with over 3000 employees offered commercial tissue-regenerative products or services with generally profitable annual sales in excess of $1.3 billion. Well over a million patients have been treated with these products. In addition, 110 development-stage companies with over 55 products in FDA-level clinical trials and other preclinical stages employed approximately 2500 scientists or support personnel and spent 850 million development dollars in 2007. These totals represent a remarkable recovery from the downturn of 2000-2002, at which time tissue engineering was in shambles because of disappointing product launches, failed regulatory trials, and the general investment pullback following the dot-com crash. Commercial success has resulted in large measure from identification of products that are achievable with available technology and under existing regulatory guidelines. Development-stage firms have become much more adept at risk management. The resilience of the field, as well as its current breadth and diversity, augurs well for the future of regenerative medicine. PMID:18333783

  14. PEDF & stem cells: niche vs. nurture.

    PubMed

    Fitchev, Philip; Chung, Chuhan; Plunkett, Beth A; Brendler, Charles B; Crawford, Susan E

    2014-01-01

    Anti-angiogenic pigment epithelium-derived factor (PEDF) is a multifunctional 50kD secreted glycoprotein emerging as a key factor in stem cell renewal. Characteristics of the stem cell niche can be highly dependent on location, access to the vasculature, oxygen tension and neighboring cells. In the neural stem cell (NSC) niche, specifically the subventricular zone, PEDF actively participates in the self renewal process and promotes stemness by upregulating Notch signaling effectors Hes1 and Hes5. The local vascular endothelial cells and ependymal cells are the likely sources of PEDF for the NSC while mesenchymal and retinal stem cells can actually produce PEDF. The opposing actions of PEDF and VEGF on various cells are recapitulated in the NSC niche. Intraventricular injection of PEDF promotes stem cell renewal, while injection of VEGF prompts differentiation and neurogenesis in the subventricular zone. Enhancing the expression of PEDF in stem cells has promising therapeutic implications. Bone marrow mesenchymal stem cells overexpressing PEDF effectively inhibited pathologic angiogenesis in the murine eye and these same cells suppressed hepatocellular carcinoma growth. As a protein with bioactivities in nearly all normal organ systems, it is likely that PEDF will continue to gain visibility as an essential component in the development and delivery of novel stem cell-based therapies to combat disease.

  15. Coordination of insulin and Notch pathway activities by microRNA miR-305 mediates adaptive homeostasis in the intestinal stem cells of the Drosophila gut.

    PubMed

    Foronda, David; Weng, Ruifen; Verma, Pushpa; Chen, Ya-Wen; Cohen, Stephen M

    2014-11-01

    Homeostasis of the intestine is maintained by dynamic regulation of a pool of intestinal stem cells. The balance between stem cell self-renewal and differentiation is regulated by the Notch and insulin signaling pathways. Dependence on the insulin pathway places the stem cell pool under nutritional control, allowing gut homeostasis to adapt to environmental conditions. Here we present evidence that miR-305 is required for adaptive homeostasis of the gut. miR-305 regulates the Notch and insulin pathways in the intestinal stem cells. Notably, miR-305 expression in the stem cells is itself under nutritional control via the insulin pathway. This link places regulation of Notch pathway activity under nutritional control. These findings provide a mechanism through which the insulin pathway controls the balance between stem cell self-renewal and differentiation that is required for adaptive homeostasis in the gut in response to changing environmental conditions.

  16. Novel anticancer activity of phloroglucinol against breast cancer stem-like cells

    SciTech Connect

    Kim, Rae-Kwon; Uddin, Nizam; Hyun, Jin-Won; Kim, Changil; Suh, Yongjoon; Lee, Su-Jae

    2015-08-01

    Poor prognosis of breast cancer patients is closely associated with metastasis and relapse. There is substantial evidence supporting that cancer stem-like cells (CSCs) are primarily responsible for relapse in breast cancer after anticancer treatment. However, there is a lack of suitable drugs that target breast cancer stem-like cells (BCSCs). Here, we report that phloroglucinol (PG), a natural phlorotannin component of brown algae, suppresses sphere formation, anchorage-independent colony formation and in vivo tumorigenicity. In line with these observations, treatment with PG also decreased CD44{sup +} cancer cell population as well as expression of CSC regulators such as Sox2, CD44, Oct4, Notch2 and β-catenin. Also, treatment with PG sensitized breast cancer cells to anticancer drugs such as cisplatin, etoposide, and taxol as well as to ionizing radiation. Importantly, PG inhibited KRAS and its downstream PI3K/AKT and RAF-1/ERK signaling pathways that regulate the maintenance of CSCs. Taken together, our findings implicate PG as a good candidate to target BCSCs and to prevent the disease relapse. - Highlights: • Phloroglucinol suppresses in vivo tumor formation. • Phloroglucinol sensitizes breast cancer cells to anticancer agents. • Phloroglucinol inhibits breast cancer stem-like cells. • Phloroglucinol inhibits PI3K/AKT and KRAS/RAF/ERK signaling pathways.

  17. BMP15 gene is activated during human amniotic fluid stem cell differentiation into oocyte-like cells.

    PubMed

    Cheng, Xiang; Chen, Shuai; Yu, Xiaoli; Zheng, Pengsheng; Wang, Huayan

    2012-07-01

    The generation of oocyte-like cells (OLCs) from stem cell differentiation in vitro provides an optimal approach for studying the mechanism of oocyte development and maturation. The aim of this study was to investigate the activation of bone morphogenetic protein 15 gene (BMP15) during the differentiation of human amniotic fluid stem cells (hAFSCs) into OLCs. After 15 days of differentiation, OLCs with a diameter of 50-60 μm and zona pellucida (ZP)-like morphology were observed. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed the BMP15 was activated from approximately day 10 of differentiating hAFSCs and thereafter. The reporter construct pBMP15-enhanced green fluorescent protein (EGFP) was transiently transfected into the differentiated hAFSCs and the EGFP expression driven by the BMP15 promoter was positive in the OLCs. Moreover, RT-PCR analysis showed that the oocyte-specific markers including ZP1, ZP2, ZP3, and c-kit were expressed in the differentiated hAFSCs, and the immunofluorescence assay confirmed that the ZP2 was detected in the OLCs. Quantitative RT-PCR revealed that ZP2 and ZP3 were significantly elevated in the differentiated hAFSCs. Further, in the OLCs derived from hAFSCs, the BMP15 promoter directing the EGFP reporter was colocalized with ZP2. Together, these results illustrated that the BMP15 could be used as an oogenesis marker to track hAFSCs differentiation into the OLCs.

  18. Stem Cells in Mammalian Gonads.

    PubMed

    Wu, Ji; Ding, Xinbao; Wang, Jian

    2016-01-01

    Stem cells have great value in clinical application because of their ability to self-renew and their potential to differentiate into many different cell types. Mammalian gonads, including testes for males and ovaries for females, are composed of germline and somatic cells. In male mammals, spermatogonial stem cells maintain spermatogenesis which occurs continuously in adult testis. Likewise, a growing body of evidence demonstrated that female germline stem cells could be found in mammalian ovaries. Meanwhile, prior studies have shown that somatic stem cells exist in both testes and ovaries. In this chapter, we focus on mammalian gonad stem cells and discuss their characteristics as well as differentiation potentials.

  19. Tissue-specific designs of stem cell hierarchies.

    PubMed

    Visvader, Jane E; Clevers, Hans

    2016-04-01

    Recent work in the field of stem cell biology suggests that there is no single design for an adult tissue stem cell hierarchy, and that different tissues employ distinct strategies to meet their self-renewal and repair requirements. Stem cells may be multipotent or unipotent, and can exist in quiescent or actively dividing states. 'Professional' stem cells may also co-exist with facultative stem cells, which are more specialized daughter cells that revert to a stem cell state under specific tissue damage conditions. Here, we discuss stem cell strategies as seen in three solid mammalian tissues: the intestine, mammary gland and skeletal muscle. PMID:26999737

  20. Microglia activated by IL-4 or IFN-gamma differentially induce neurogenesis and oligodendrogenesis from adult stem/progenitor cells.

    PubMed

    Butovsky, Oleg; Ziv, Yaniv; Schwartz, Adi; Landa, Gennady; Talpalar, Adolfo E; Pluchino, Stefano; Martino, Gianvito; Schwartz, Michal

    2006-01-01

    Cell renewal in the adult central nervous system (CNS) is limited, and is blocked in inflammatory brain conditions. We show that both neurogenesis and oligodendrogenesis of adult neural progenitor cells in mice are blocked by inflammation-associated (endotoxin-activated) microglia, but induced by microglia activated by cytokines (IL-4 or low level of IFN-gamma) associated with T-helper cells. Blockage was correlated with up-regulation of microglial production of tumor necrosis factor-alpha. The effect induced by IL-4-activated microglia was mediated, at least in part, by insulin-like growth factor-I. The IL-4-activated microglia showed a bias towards oligodendrogenesis whereas the IFN-gamma-activated microglia showed a bias towards neurogenesis. It thus appears that microglial phenotype critically affects their ability to support or impair cell renewal from adult stem cell.

  1. Stem cells and the Planarian Schmidtea mediterranea.

    PubMed

    Sánchez Alvarado, Alejandro

    2007-01-01

    In recent years, stem cells have been heralded as potential therapeutic agents to address a large number of degenerative diseases. Yet, in order to rationally utilize these cells as effective therapeutic agents, and/or improve treatment of stem-cell-associated malignancies such as leukemias and carcinomas, a better understanding of the basic biological properties of stem cells needs to be acquired. A major limitation in the study of stem cells lies in the difficulty of accessing and studying these cells in vivo. This barrier is further compounded by the limitations of in vitro culture systems, which are unable to emulate the microenvironments in which stem cells reside and which are known to provide critical regulatory signals for their proliferation and differentiation. Given the complexity of vertebrate embryonic and adult stem cell populations and their relative inaccessibility to in vivo molecular analyses, the study of stem cells should benefit from analyzing their counterparts in simpler model organisms. In the past, the use of Drosophila or C. elegans has provided invaluable contributions to our understanding of genes and pathways involved in a variety of human diseases. However, stem cells in these organisms are mostly restricted to the gonads, and more importantly neither Drosophila, nor C. elegans are capable of regenerating body parts lost to injury. Therefore, a simple animal with experimentally accessible stem cells playing a role in tissue maintenance and/or regeneration should be very useful in identifying and functionally testing the mechanisms regulating stem cell activities. The planarian Schmidtea mediterranea is poised to fill this experimental gap. S. mediterranea displays robust regenerative properties driven by a stem cell population capable of producing the approximately 40 different cell types found in this organism, including the germ cells. Given that all known metazoans depend on stem cells for their survival, it is extremely likely that

  2. Characterization of amniotic stem cells.

    PubMed

    Koike, Chika; Zhou, Kaixuan; Takeda, Yuji; Fathy, Moustafa; Okabe, Motonori; Yoshida, Toshiko; Nakamura, Yukio; Kato, Yukio; Nikaido, Toshio

    2014-08-01

    The amnion membrane is developed from embryo-derived cells, and amniotic cells have been shown to exhibit multidifferentiation potential. These cells represent a desirable source for stem cells for a variety of reasons. However, to date very few molecular analyses of amnion-derived cells have been reported, and efficient markers for isolating the stem cells remain unclear. This paper assesses the characterization of amnion-derived cells as stem cells by examining stemness marker expressions for amnion-derived epithelial cells and mesenchymal cells by flow cytometry, immunocytochemistry, and quantitative PCR. Flow cytometry revealed that amnion epithelial cells expressed CD133, CD 271, and TRA-1-60, whereas mecenchymal cells expressed CD44, CD73, CD90, and CD105. Immunohistochemistry showed that both cells expressed the stemness markers Oct3/4, Sox2, Klf4, and SSEA4. Stemness genes' expression in amnion epithelial cells, mesenchymal cells, fibroblast, bone marrow-derived mesenchymal stem cells (MSCs), and induced pluripotent stem cells (iPSCs) was compared by quantitative reverse-transcription polymerase chain reaction (RT-PCR). Amnion-derived epithelial cells and mesenchymal cells expressed Oct3/4, Nanog, and Klf4 more than bone marrow-derived MSCs. The sorted TRA1-60-positive cells expressed Oct3/4, Nanog, and Klf4 more than unsorted cells or TRA1-60-negative cells. TRA1-60 can be a marker for isolating amnion epithelial stem cells.

  3. Directed Endothelial Progenitor Differentiation from Human Pluripotent Stem Cells Via Wnt Activation Under Defined Conditions.

    PubMed

    Bao, Xiaoping; Lian, Xiaojun; Palecek, Sean P

    2016-01-01

    Efficient derivation of endothelial cells and their progenitors from human pluripotent stem cells (hPSCs) can facilitate studies of human vascular development, disease modeling, drug discovery, and cell-based therapy. Here we provide a detailed protocol for directing hPSCs to functional endothelial cells and their progenitors in a completely defined, growth factor- and serum-free system by temporal modulation of Wnt/β-catenin signaling via small molecules. We demonstrate a 10-day, two-stage process that recapitulates endothelial cell development, in which hPSCs first differentiate to endothelial progenitors that then generate functional endothelial cells and smooth muscle cells. Methods to characterize endothelial cell identity and function are also described. PMID:27590162

  4. Human cancer cells with stem cell-like phenotype exhibit enhanced sensitivity to the cytotoxicity of IL-2 and IL-15 activated natural killer cells.

    PubMed

    Yin, Tao; Wang, Guoping; He, Sisi; Liu, Qin; Sun, Jianhong; Wang, Yongsheng

    2016-02-01

    Tumors harbor a population of cancer stem cells (CSCs) which can drive tumor progression and therapeutical resistance. Nature killer (NK) cells are best known for their ability to directly recognize and kill malignant cells. However, the susceptibility of cancer stem cells to NK cells is not fully understood. Here we demonstrated that human CD44+CD24- breast CSCs were shown enhanced sensitivity to IL-2 and IL-15 activated NK cells. CD44+CD24- CSCs expressed higher levels of NKG2D ligands ULBP1, ULBP2 and MICA. Blockade assay showed that the sensitivity of CSCs to NK cells-mediated lysis was mainly dependent on NKG2D. Furthermore, redox oxygen species (ROS)-low tumor cells were more sensitive to NK cells. The presence of antioxidant enzymes inhibitor L-S,R-buthionine sulfoximine or H2O2 retarded the cytotoxicity of NK cells to CD44+CD24- CSCs. In addition, NK cells could readily target CD133+ colonal CSCs. Our findings provide novel targets for NK cells-based immunotherapy and are of great importance for translational medicine.

  5. Increase of mesenchymal stem cell migration by cannabidiol via activation of p42/44 MAPK.

    PubMed

    Schmuhl, Ellen; Ramer, Robert; Salamon, Achim; Peters, Kirsten; Hinz, Burkhard

    2014-02-01

    Migration and differentiation of mesenchymal stem cells (MSCs) are known to be involved in various regenerative processes such as bone healing. However, little is known about the pharmacotherapeutical options aiming at the mobilization and differentiation of MSCs. The present study therefore focussed on cannabinoids which have been demonstrated to exhibit tissue healing properties. Using Boyden chamber assays, the non-psychoactive phytocannabinoid cannabidiol (CBD) was found to increase the migration of adipose-derived MSCs in a time- and concentration-dependent manner. CBD-induced migration was inhibited by AM-630 (CB₂ receptor antagonist) and O-1602 (G protein-coupled receptor 55 [GRP55] agonist). Moreover, the promigratory effect of CBD was antagonized by inhibition of the p42/44 mitogen-activated protein kinase (MAPK) pathway which became activated upon CBD treatment. In line with this data, AM-630 and O-1602 attenuated CBD-induced p42/44 MAPK phosphorylation. A p42/44 MAPK-dependent promigratory effect was likewise demonstrated for the GPR55 antagonist O-1918 and the selective CB₂ receptor agonist JWH-133. Additional evidence for a functional effect of CBD on MSCs was provided by experiments demonstrating long-term stimulation with CBD to induce differentiation of MSCs into the osteoblastic lineage as evidenced by increased mineralization assessed by cresolphthalein complexone assay and enhanced activity of alkaline phosphatase. Collectively, this study demonstrates CBD to promote the migration of MSCs via activation of the CB₂ receptor and inhibition of GPR55 and to induce osteoblastic differentiation. CBD may therefore recruit MSCs to sites of calcifying tissue regeneration and subsequently support bone regeneration via an osteoanabolic action on MSCs.

  6. Xeno-sensing activity of the aryl hydrocarbon receptor in human pluripotent stem cell-derived hepatocyte-like cells

    PubMed Central

    Kim, Hye-Min; Kim, Ji-Woo; Choi, Youngjun; Chun, Hang-Suk; Im, Ilkyun; Han, Yong-Mahn; Song, Chang-Woo; Yoon, Seokjoo; Park, Han-Jin

    2016-01-01

    Although hepatocyte-like cells derived from human pluripotent stem cells (hPSC-HLCs) are considered a promising model for predicting hepatotoxicity, their application has been restricted because of the low activity of drug metabolizing enzymes (DMEs). Here we found that the low expression of xenobiotic receptors (constitutive androstane receptor, CAR; and pregnane X receptor, PXR) contributes to the low activity of DMEs in hPSC-HLCs. Most CAR- and PXR-regulated DMEs and transporters were transcriptionally down-regulated in hPSC-HLC. Transcriptional expression of CAR and PXR was highly repressed in hPSC-HLCs, whereas mRNA levels of aryl hydrocarbon receptor (AHR) were comparable to those of adult liver. Furthermore, ligand-induced transcriptional activation was observed only at AHR in hPSC-HLCs. Bisulfite sequencing analysis demonstrated that promoter hypermethylation of CAR and PXR was associated with diminished transcriptional activity in hPSC-HLCs. Treatment with AHR-selective ligands increased the transcription of AHR-dependent target genes by direct AHR-DNA binding at the xenobiotic response element. In addition, an antagonist of AHR significantly inhibited AHR-dependent target gene expression. Thus, AHR may function intrinsically as a xenosensor as well as a ligand-dependent transcription factor in hPSC-HLCs. Our results indicate that hPSC-HLCs can be used to screen toxic substances related to AHR signaling and to identify potential AHR-targeted therapeutics. PMID:26899675

  7. Materials as stem cell regulators

    NASA Astrophysics Data System (ADS)

    Murphy, William L.; McDevitt, Todd C.; Engler, Adam J.

    2014-06-01

    The stem cell/material interface is a complex, dynamic microenvironment in which the cell and the material cooperatively dictate one another's fate: the cell by remodelling its surroundings, and the material through its inherent properties (such as adhesivity, stiffness, nanostructure or degradability). Stem cells in contact with materials are able to sense their properties, integrate cues via signal propagation and ultimately translate parallel signalling information into cell fate decisions. However, discovering the mechanisms by which stem cells respond to inherent material characteristics is challenging because of the highly complex, multicomponent signalling milieu present in the stem cell environment. In this Review, we discuss recent evidence that shows that inherent material properties may be engineered to dictate stem cell fate decisions, and overview a subset of the operative signal transduction mechanisms that have begun to emerge. Further developments in stem cell engineering and mechanotransduction are poised to have substantial implications for stem cell biology and regenerative medicine.

  8. Materials as stem cell regulators

    PubMed Central

    Murphy, William L.; McDevitt, Todd C.; Engler, Adam J.

    2014-01-01

    The stem cell/material interface is a complex, dynamic microenvironment in which the cell and the material cooperatively dictate one another's fate: the cell by remodelling its surroundings, and the material through its inherent properties (such as adhesivity, stiffness, nanostructure or degradability). Stem cells in contact with materials are able to sense their properties, integrate cues via signal propagation and ultimately translate parallel signalling information into cell fate decisions. However, discovering the mechanisms by which stem cells respond to inherent material characteristics is challenging because of the highly complex, multicomponent signalling milieu present in the stem cell environment. In this Review, we discuss recent evidence that shows that inherent material properties may be engineered to dictate stem cell fate decisions, and overview a subset of the operative signal transduction mechanisms that have begun to emerge. Further developments in stem cell engineering and mechanotransduction are poised to have substantial implications for stem cell biology and regenerative medicine. PMID:24845994

  9. The effect of space microgravity on the physiological activity of mammalian resident cardiac stem cells

    NASA Astrophysics Data System (ADS)

    Belostotskaya, Galina; Zakharov, Eugeny

    Prolonged exposure to weightlessness during space flights is known to cause depression of heart function in mammals. The decrease in heart weight and its remodeling under the influence of prolonged weightlessness (or space microgravity) is assumed to be due to both morphological changes of working cardiomyocytes and their progressive loss, as well as to possible depletion of resident cardiac stem cells (CSCs) population, or their inability to self-renewal and regeneration of muscle tissue under conditions of weightlessness. We have previously shown that the presence of different maturity clones formed by resident CSCs not only in culture but also in the mammalian myocardium can be used as an indicator of the regenerative activity of myocardial cells [Belostotskaya, et al., 2013: 2014]. In this study, we were interested to investigate whether the 30-day near-Earth space flight on the spacecraft BION-M1 affects the regenerative potential of resident CSCs. Immediately after landing of the spacecraft, we had examined the presence of resident c-kit+, Sca-1+ and Isl1+ CSCs and their development in suspension of freshly isolated myocardial cells of C57BL mice in comparison to controls. Cardiac cell suspension was obtained by enzymatic digestion of the heart [Belostotskaya and Golovanova, 2014]. Immunocytochemically stained preparations of fixed cells were analyzed with confocal microscope Leica TCS SP5 (Germany) in the Resource Center of St-Petersburg State University. CSCs were labeled with appropriate antibodies. CSCs differentiation into mature cardiomyocytes was verified using antibodies to Sarcomeric α-Actinin and Cardiac Troponin T. Antibodies to Connexin43 were used to detect cell-cell contacts. All antibodies were conjugated with Alexa fluorochromes (488, 532, 546, 568, 594 and/or 647 nm), according to Zenon-technology (Invitrogen). It has been shown that, under identical conditions of cell isolation, more complete digestion of heart muscle was observed in

  10. Mesenchymal Stem Cell Therapy Alleviates Interstitial Cystitis by Activating Wnt Signaling Pathway

    PubMed Central

    Song, Miho; Lim, Jisun; Yu, Hwan Yeul; Park, Junsoo; Chun, Ji-Youn; Jeong, Jaeho; Heo, Jinbeom; Kang, Hyunsook; Kim, YongHwan; Cho, Yong Mee; Kim, Seong Who; Oh, Wonil; Choi, Soo Jin; Jang, Sung-Wuk; Park, Sanghyeok

    2015-01-01

    Interstitial cystitis (IC) is a syndrome characterized by urinary urgency, frequency, pelvic pain, and nocturia in the absence of bacterial infection or identifiable pathology. IC is a devastating disease that certainly decreases quality of life. However, the causes of IC remain unknown and no effective treatments or cures have been developed. This study evaluated the therapeutic potency of using human umbilical cord-blood-derived mesenchymal stem cells (UCB-MSCs) to treat IC in a rat model and to investigate its responsible molecular mechanism. IC was induced in 10-week-old female Sprague–Dawley rats via the instillation of 0.1 M HCl or phosphate-buffered saline (PBS; sham). After 1 week, human UCB-MSC (IC+MSC) or PBS (IC) was directly injected into the submucosal layer of the bladder. A single injection of human UCB-MSCs significantly attenuated the irregular and decreased voiding interval in the IC group. Accordingly, denudation of the epithelium and increased inflammatory responses, mast cell infiltration, neurofilament production, and angiogenesis observed in the IC bladders were prevented in the IC+MSC group. The injected UCB-MSCs successfully engrafted to the stromal and epithelial tissues and activated Wnt signaling cascade. Interference with Wnt and epidermal growth factor receptor activity by small molecules abrogated the benefits of MSC therapy. This is the first report that provides an experimental evidence of the therapeutic effects and molecular mechanisms of MSC therapy to IC using an orthodox rat animal model. Our findings not only provide the basis for clinical trials of MSC therapy to IC but also advance our understanding of IC pathophysiology. PMID:25745847

  11. C. elegans GLP-1/Notch activates transcription in a probability gradient across the germline stem cell pool

    PubMed Central

    Lee, ChangHwan; Sorensen, Erika B; Lynch, Tina R; Kimble, Judith

    2016-01-01

    C. elegans Notch signaling maintains a pool of germline stem cells within their single-celled mesenchymal niche. Here we investigate the Notch transcriptional response in germline stem cells using single-molecule fluorescence in situ hybridization coupled with automated, high-throughput quantitation. This approach allows us to distinguish Notch-dependent nascent transcripts in the nucleus from mature mRNAs in the cytoplasm. We find that Notch-dependent active transcription sites occur in a probabilistic fashion and, unexpectedly, do so in a steep gradient across the stem cell pool. Yet these graded nuclear sites create a nearly uniform field of mRNAs that extends beyond the region of transcriptional activation. Therefore, active transcription sites provide a precise view of where the Notch-dependent transcriptional complex is productively engaged. Our findings offer a new window into the Notch transcriptional response and demonstrate the importance of assaying nascent transcripts at active transcription sites as a readout for canonical signaling. DOI: http://dx.doi.org/10.7554/eLife.18370.001 PMID:27705743

  12. mTOR inhibition decreases SOX2-SOX9 mediated glioma stem cell activity and temozolomide resistance

    PubMed Central

    Garros-Regulez, Laura; Aldaz, Paula; Arrizabalaga, Olatz; Moncho-Amor, Veronica; Carrasco-Garcia, Estefania; Manterola, Lorea; Moreno-Cugnon, Leire; Barrena, Cristina; Villanua, Jorge; Ruiz, Irune; Pollard, Steven; Lovell-Badge, Robin; Sampron, Nicolas; Garcia, Idoia; Matheu, Ander

    2016-01-01

    ABSTRACT Background: SOX2 and SOX9 are commonly overexpressed in glioblastoma, and regulate the activity of glioma stem cells (GSCs). Their specific and overlapping roles in GSCs and glioma treatment remain unclear. Methods: SOX2 and SOX9 levels were examined in human biopsies. Gain and loss of function determined the impact of altering SOX2 and SOX9 on cell proliferation, senescence, stem cell activity, tumorigenesis and chemoresistance. Results: SOX2 and SOX9 expression correlates positively in glioma cells and glioblastoma biopsies. High levels of SOX2 bypass cellular senescence and promote resistance to temozolomide. Mechanistic investigations revealed that SOX2 acts upstream of SOX9. mTOR genetic and pharmacologic (rapamycin) inhibition decreased SOX2 and SOX9 expression, and reversed chemoresistance. Conclusions: Our findings reveal SOX2-SOX9 as an oncogenic axis that regulates stem cell properties and chemoresistance. We identify that rapamycin abrogate SOX protein expression and provide evidence that a combination of rapamycin and temozolomide inhibits tumor growth in cells with high SOX2/SOX9. PMID:26878385

  13. β-Catenin is important for cancer stem cell generation and tumorigenic activity in nasopharyngeal carcinoma.

    PubMed

    Jiang, Rui; Niu, Xiaoshuang; Huang, Yuxiang; Wang, Xiaosheng

    2016-03-01

    Nasopharyngeal carcinoma (NPC) is one of the most common malignant tumors with poor prognosis and recurrence in South China. The hard eradication of NPC in clinic is predominantly due to cancer stem cells (CSCs). Increasing evidence revealed that the aberrant activation of Wnt/β-catenin was positively correlated with the produce of CSCs. To further investigate the effect of β-catenin on CSCs and tumorigenesis in NPC, a CNE2 cell line (pLKO.1-sh-β-catenin-CNE2) with stably suppressed expression of β-catenin was used in this study. The expressions of biomarkers in CSCs including c-myc, Nanog, Oct3/4, Sox2, EpCAM as well as adhesion-related proteins like E-cadherin and vimentin were analyzed by western blot analysis and immunofluorescent staining. The proliferation and migration abilities were investigated by MTT assay and Transwell assay, respectively. Cell cycle was analyzed by flow cytometry. Finally, xenograft was performed to determine the effect of β-catenin on oncogenesis in vivo. Results showed that the expressions of c-myc, Nanog, Oct3/4, Sox2, and EpCAM were all decreased in pLKO.1-sh-β-catenin-CNE2 cells. It was also found that vimentin was downregulated, while E-cadherin was upregulated. Results of MTT and Transwell assays suggested that the proliferation and migration abilities were impaired by silencing of β-catenin, and more cells were arrested in G1 phase when compared with the control. In vivo study indicated that the tumor growth was markedly suppressed in experimental group. Based on current findings, β-catenin may function as an essential protein for the maintenance of migration and proliferation abilities of NPC cells, and a complicated network consisting of c-myc, Nanog, Oct3/4, Sox2, EpCAM, E-cadherin, vimentin, and β-catenin may be involved in the inherent regulation mechanisms. PMID:26849897

  14. Tgif1 Counterbalances the Activity of Core Pluripotency Factors in Mouse Embryonic Stem Cells.

    PubMed

    Lee, Bum-Kyu; Shen, Wenwen; Lee, Jiwoon; Rhee, Catherine; Chung, Haewon; Kim, Kun-Yong; Park, In-Hyun; Kim, Jonghwan

    2015-10-01

    Core pluripotency factors, such as Oct4, Sox2, and Nanog, play important roles in maintaining embryonic stem cell (ESC) identity by autoregulatory feedforward loops. Nevertheless, the mechanism that provides precise control of the levels of the ESC core factors without indefinite amplification has remained elusive. Here, we report the direct repression of core pluripotency factors by Tgif1, a previously known terminal repressor of TGFβ/activin/nodal signaling. Overexpression of Tgif1 reduces the levels of ESC core factors, whereas its depletion leads to the induction of the pluripotency factors. We confirm the existence of physical associations between Tgif1 and Oct4, Nanog, and HDAC1/2 and further show the level of Tgif1 is not significantly altered by treatment with an activator/inhibitor of the TGFβ/activin/nodal signaling. Collectively, our findings establish Tgif1 as an integral member of the core regulatory circuitry of mouse ESCs that counterbalances the levels of the core pluripotency factors in a TGFβ/activin/nodal-independent manner. PMID:26411691

  15. Pituitary Adenlylate Cyclase Activating Peptide Protects Adult Neural Stem Cells from a Hypoglycaemic milieu

    PubMed Central

    Mansouri, Shiva; Lietzau, Grazyna; Lundberg, Mathias; Nathanson, David; Nyström, Thomas; Patrone, Cesare

    2016-01-01

    Hypoglycaemia is a common side-effect of glucose-lowering therapies for type-2 diabetic patients, which may cause cognitive/neurological impairment. Although the effects of hypoglycaemia in the brain have been extensively studied in neurons, how hypoglycaemia impacts the viability of adult neural stem cells (NSCs) has been poorly investigated. In addition, the cellular and molecular mechanisms of how hypoglycaemia regulates NSCs survival have not been characterized. Recent work others and us have shown that the pituitary adenylate cyclase-activating polypeptide (PACAP) and the glucagon-like peptide-1 receptor (GLP-1R) agonist Exendin-4 stimulate NSCs survival against glucolipoapoptosis. The aim of this study was to establish an in vitro system where to study the effects of hypoglycaemia on NSC survival. Furthermore, we determine the potential role of PACAP and Exendin-4 in counteracting the effect of hypoglycaemia. A hypoglycaemic in vitro milieu was mimicked by exposing subventricular zone-derived NSC to low levels of glucose. Moreover, we studied the potential involvement of apoptosis and endoplasmic reticulum stress by quantifying protein levels of Bcl-2, cleaved caspase-3 and mRNA levels of CHOP. We show that PACAP via PAC-1 receptor and PKA activation counteracts impaired NSC viability induced by hypoglycaemia. The protective effect induced by PACAP correlated with endoplasmic reticulum stress, Exendin-4 was ineffective. The results show that hypoglycaemia decreases NSC viability and that this effect can be substantially counteracted by PACAP via PAC-1 receptor activation. The data supports a potential therapeutic role of PAC-1 receptor agonists for the treatment of neurological complications, based on neurogenesis impairment by hypoglycaemia. PMID:27305000

  16. Dental mesenchymal stem cells.

    PubMed

    Sharpe, Paul T

    2016-07-01

    Mammalian teeth harbour mesenchymal stem cells (MSCs), which contribute to tooth growth and repair. These dental MSCs possess many in vitro features of bone marrow-derived MSCs, including clonogenicity, expression of certain markers, and following stimulation, differentiation into cells that have the characteristics of osteoblasts, chondrocytes and adipocytes. Teeth and their support tissues provide not only an easily accessible source of MSCs but also a tractable model system to study their function and properties in vivo In addition, the accessibility of teeth together with their clinical relevance provides a valuable opportunity to test stem cell-based treatments for dental disorders. This Review outlines some recent discoveries in dental MSC function and behaviour and discusses how these and other advances are paving the way for the development of new biologically based dental therapies. PMID:27381225

  17. Cdk1 Activates Pre-mitotic Nuclear Envelope Dynein Recruitment and Apical Nuclear Migration in Neural Stem Cells.

    PubMed

    Baffet, Alexandre D; Hu, Daniel J; Vallee, Richard B

    2015-06-22

    Dynein recruitment to the nuclear envelope is required for pre-mitotic nucleus-centrosome interactions in nonneuronal cells and for apical nuclear migration in neural stem cells. In each case, dynein is recruited to the nuclear envelope (NE) specifically during G2 via two nuclear pore-mediated mechanisms involving RanBP2-BicD2 and Nup133-CENP-F. The mechanisms responsible for cell-cycle control of this behavior are unknown. We now find that Cdk1 serves as a direct master controller for NE dynein recruitment in neural stem cells and HeLa cells. Cdk1 phosphorylates conserved sites within RanBP2 and activates BicD2 binding and early dynein recruitment. Late recruitment is triggered by a Cdk1-induced export of CENP-F from the nucleus. Forced NE targeting of BicD2 overrides Cdk1 inhibition, fully rescuing dynein recruitment and nuclear migration in neural stem cells. These results reveal how NE dynein recruitment is cell-cycle regulated and identify the trigger mechanism for apical nuclear migration in the brain.

  18. [Perinatal sources of stem cells].

    PubMed

    Piskorska-Jasiulewicz, Magdalena Maria; Witkowska-Zimny, Małgorzata

    2015-03-08

    Recently, stem cell biology has become an interesting topic. Several varieties of human stem cells have been isolated and identified in vivo and in vitro. Successful application of hematopoietic stem cells in hematology has led to the search for other sources of stem cells and expanding the scale of their application. Perinatal stem cells are a versatile cell population, and they are interesting for both scientific and practical objectives. Stem cells from perinatal tissue may be particularly useful in the clinic for autologous transplantation for fetuses and newborns, and after banking in later stages of life, as well as for in utero transplantation in the case of genetic disorders. In this review paper we focus on the extraction and therapeutic potential of stem cells derived from perinatal tissues such as the placenta, the amnion, amniotic fluid, umbilical cord blood and Wharton's jelly.

  19. Acute GVHD in patients receiving IL-15/4-1BBL activated NK cells following T-cell-depleted stem cell transplantation.

    PubMed

    Shah, Nirali N; Baird, Kristin; Delbrook, Cynthia P; Fleisher, Thomas A; Kohler, Mark E; Rampertaap, Shakuntala; Lemberg, Kimberly; Hurley, Carolyn K; Kleiner, David E; Merchant, Melinda S; Pittaluga, Stefania; Sabatino, Marianna; Stroncek, David F; Wayne, Alan S; Zhang, Hua; Fry, Terry J; Mackall, Crystal L

    2015-01-29

    Natural killer (NK) cells can enhance engraftment and mediate graft-versus-leukemia following allogeneic hematopoietic stem cell transplantation (HSCT), but the potency of graft-versus-leukemia mediated by naturally reconstituting NK cells following HSCT is limited. Preclinical studies demonstrate that activation of NK cells using interleukin-15 (IL-15) plus 4-1BBL upregulates activating receptor expression and augments killing capacity. In an effort to amplify the beneficial effects of NK cells post-HSCT, we conducted a first-in-human trial of adoptive transfer of donor-derived IL-15/4-1BBL-activated NK cells (aNK-DLI) following HLA-matched, T-cell-depleted (1-2 × 10(4) T cells/kg) nonmyeloablative peripheral blood stem cell transplantation in children and young adults with ultra-high-risk solid tumors. aNK-DLI were CD3(+)-depleted, CD56(+)-selected lymphocytes, cultured for 9 to 11 days with recombinant human IL-15 plus 4-1BBL(+)IL-15Rα(+) artificial antigen-presenting cells. aNK-DLI demonstrated potent killing capacity and displayed high levels of activating receptor expression. Five of 9 transplant recipients experienced acute graft-versus-host disease (GVHD) following aNK-DLI, with grade 4 GVHD observed in 3 subjects. GVHD was more common in matched unrelated donor vs matched sibling donor recipients and was associated with higher donor CD3 chimerism. Given that the T-cell dose was below the threshold required for GVHD in this setting, we conclude that aNK-DLI contributed to the acute GVHD observed, likely by augmenting underlying T-cell alloreactivity. This trial was registered at www.clinicaltrials.gov as #NCT01287104. PMID:25452614

  20. Acute GVHD in patients receiving IL-15/4-1BBL activated NK cells following T-cell-depleted stem cell transplantation.

    PubMed

    Shah, Nirali N; Baird, Kristin; Delbrook, Cynthia P; Fleisher, Thomas A; Kohler, Mark E; Rampertaap, Shakuntala; Lemberg, Kimberly; Hurley, Carolyn K; Kleiner, David E; Merchant, Melinda S; Pittaluga, Stefania; Sabatino, Marianna; Stroncek, David F; Wayne, Alan S; Zhang, Hua; Fry, Terry J; Mackall, Crystal L

    2015-01-29

    Natural killer (NK) cells can enhance engraftment and mediate graft-versus-leukemia following allogeneic hematopoietic stem cell transplantation (HSCT), but the potency of graft-versus-leukemia mediated by naturally reconstituting NK cells following HSCT is limited. Preclinical studies demonstrate that activation of NK cells using interleukin-15 (IL-15) plus 4-1BBL upregulates activating receptor expression and augments killing capacity. In an effort to amplify the beneficial effects of NK cells post-HSCT, we conducted a first-in-human trial of adoptive transfer of donor-derived IL-15/4-1BBL-activated NK cells (aNK-DLI) following HLA-matched, T-cell-depleted (1-2 × 10(4) T cells/kg) nonmyeloablative peripheral blood stem cell transplantation in children and young adults with ultra-high-risk solid tumors. aNK-DLI were CD3(+)-depleted, CD56(+)-selected lymphocytes, cultured for 9 to 11 days with recombinant human IL-15 plus 4-1BBL(+)IL-15Rα(+) artificial antigen-presenting cells. aNK-DLI demonstrated potent killing capacity and displayed high levels of activating receptor expression. Five of 9 transplant recipients experienced acute graft-versus-host disease (GVHD) following aNK-DLI, with grade 4 GVHD observed in 3 subjects. GVHD was more common in matched unrelated donor vs matched sibling donor recipients and was associated with higher donor CD3 chimerism. Given that the T-cell dose was below the threshold required for GVHD in this setting, we conclude that aNK-DLI contributed to the acute GVHD observed, likely by augmenting underlying T-cell alloreactivity. This trial was registered at www.clinicaltrials.gov as #NCT01287104.

  1. Stimulation of Periodontal Ligament Stem Cells by Dentin Matrix Protein 1 Activates Mitogen-Activated Protein Kinase and Osteoblast Differentiation

    PubMed Central

    Chandrasekaran, Sangeetha; Ramachandran, Amsaveni; Eapen, Asha; George, Anne

    2013-01-01

    Background Periodontitis can ultimately result in tooth loss. Many natural and synthetic materials have been tried to achieve periodontal regeneration, but the results remain variable and unpredictable. We hypothesized that exogenous treatment with dentin matrix protein 1 (DMP1) activates specific genes and results in phenotypic and functional changes in human periodontal ligament stem cells (hPDLSCs). Methods hPDLSCs were isolated from extracted teeth and cultured in the presence or absence of DMP1. Quantitative polymerase chain reactions were performed to analyze the expression of several genes involved in periodontal regeneration. hPDLSCs were also processed for immunocytochemical and Western blot analysis using phosphorylated extracellular signal-regulated kinase (pERK) and ERK antibodies. Alkaline phosphatase and von Kossa staining were performed to characterize the differentiation of hPDLSCs into osteoblasts. Field emission scanning electron microscopic analysis of the treated and control cell cultures were also performed. Results Treatment with DMP1 resulted in the upregulation of genes, such as matrix metalloproteinase-2, alkaline phosphatase, and transforming growth factor β1. Activation of ERK mitogen-activated protein kinase signaling pathway and translocation of pERK from the cytoplasm to the nucleus was observed. Overall, DMP1-treated cells showed increased expression of alkaline phosphatase, increased matrix, and mineralized nodule formation when compared with untreated controls. Conclusion DMP1 can orchestrate a coordinated expression of genes and phenotypic changes in hPDLSCs by activation of the ERK signaling pathway, which may provide a valuable strategy for tissue engineering approaches in periodontal regeneration. PMID:22612367

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

    NASA Astrophysics Data System (ADS)

    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.

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

    PubMed Central

    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.

    2015-01-01

    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, cell-adhesion-ligand density and degradation. 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. PMID:26618884

  4. Integrin activation and internalization on soft ECM as a mechanism of induction of stem cell differentiation by ECM elasticity

    PubMed Central

    Du, Jing; Chen, Xiaofei; Liang, Xudong; Zhang, Guangyao; Xu, Jia; He, Linrong; Zhan, Qingyuan; Feng, Xi-Qiao; Chien, Shu; Yang, Chun

    2011-01-01

    The mechanism by which ECM elasticity induces lineage specification of stem cells has not been clearly understood. Integrins are well-documented mechanosensors that are positioned at the beginning of the sensing pathway. By using an antibody specifically recognizing the active conformation of β1 integrin, we observed that β1 integrin activation in bone marrow mesenchymal stem cells (BMMSCs) was induced by soft substrate to a significantly greater degree than by stiff substrate. In contrast, however, the level of cell surface integrin on soft substrate was significantly lower than that on stiff substrate. Soft substrate markedly enhanced the internalization of integrin, and this internalization was mediated mainly through caveolae/raft-dependent endocytosis. The inhibition of integrin internalization blocked the neural lineage specification of BMMSCs on soft substrate. Furthermore, soft substrate also repressed the bone morphogenetic protein (BMP)/Smad pathway at least partially through integrin-regulated BMP receptor endocytosis. A theoretical analysis based on atomic force microscopy (AFM) data indicated that integrin–ligand complexes are more easily ruptured on soft substrate; this outcome may contribute to the enhancement of integrin internalization on soft substrate. Taken together, our results suggest that ECM elasticity affects integrin activity and trafficking to modulate integrin BMP receptor internalization, thus contributing to stem cell lineage specification. PMID:21593411

  5. Graphene/single-walled carbon nanotube hybrids promoting osteogenic differentiation of mesenchymal stem cells by activating p38 signaling pathway

    PubMed Central

    Yan, Xinxin; Yang, Wen; Shao, Zengwu; Yang, Shuhua; Liu, Xianzhe

    2016-01-01

    Carbon nanomaterials are becoming increasingly significant in biomedical fields since they exhibit exceptional physicochemical and biocompatible properties. Today, the stem cells offer potentially new therapeutic approaches in tissue engineering and regenerative medicine. However, the induction of differentiation into specific lineages remains challenging, which provoked us to explore the biomedical applications of carbon nanomaterials in stem cells. In this study, we investigated the interactions between graphene/single-walled carbon nanotube (G/SWCNT) hybrids and rat mesenchymal stem cells (rMSCs) and focused on the proliferation and differentiation of rMSCs treated with G/SWCNT hybrids. Cell viability and morphology were evaluated using cell counting kit-8 assay and immunofluorescence staining, respectively. Osteogenic differentiation evaluated by alkaline phosphatase activity of MSCs proved to be higher after treatment with G/SWCNT hybrids, and the mineralized matrix nodule formation was also enhanced. In addition, the expression levels of osteogenic-associated genes were upregulated, while the adipocyte-specific markers were downregulated. Consistent with these results, we illustrated that the effect of G/SWCNT hybrids on the process of osteogenic differentiation of rMSCs can be modulated by activating the p38 signaling pathway and inhibiting the extracellular signal-regulated kinase 1/2 pathway. Nevertheless, our study suggests that carbon nanomaterials offer a promising platform for regenerative medicine in the near future. PMID:27799770

  6. Phagocytic activity of monocytes, their subpopulations and granulocytes during post-transplant adverse events after hematopoietic stem cell transplantation.

    PubMed

    Döring, Michaela; Cabanillas Stanchi, Karin Melanie; Erbacher, Annika; Haufe, Susanne; Schwarze, Carl Philipp; Handgretinger, Rupert; Hofbeck, Michael; Kerst, Gunter

    2015-05-01

    Phagocytosis of granulocytes and monocytes presents a major mechanism that contributes to the clearance of pathogens and cell debris. We analyzed the phagocytic activity of the peripheral blood cell monocytes, three monocyte subpopulations and granulocytes before and up to one year after hematopoietic stem cell transplantation, as well as during transplant-related adverse events. 25 pediatric patients and young adults (median age of 11.0 years) with hemato-oncological malignancies and non malignancies were enrolled in the prospective study. Ingestion of fluorescence-labeled Escherichia coli bacteria was used to assess the phagocytic activity of monocytes and their subpopulations and granulocytes by means of flow cytometry in the patient group as well as in a control group (n=36). During sepsis, a significant increase of phagocytic activity of monocytes (P=0.0003) and a significant decrease of the phagocytic activity of granulocytes (P=0.0003) and the CD14+ CD16++ monocyte subpopulation (P=0.0020) occurred. At the onset of a veno-occlusive disease, a significant increase of phagocytic activity in the CD14++ CD16+ monocyte subpopulation (P=0.001) and a significant decrease in the phagocytic activity of the CD14++ CD16- monocyte subpopulation (P=0.0048) were observed. In conclusion, the phagocytic activity of monocytes, their subpopulations and granulocytes might be a useful and easy determinable parameter that enables identification of post-transplant complications after hematopoietic stem cell transplantation. The alterations of phagocytic activity contribute to the altered immune response that accompanies adverse events after hematopoietic stem cell transplantation.

  7. Acetaminophen induces JNK/p38 signaling and activates the caspase-9-3-dependent cell death pathway in human mesenchymal stem cells

    PubMed Central

    YIANG, GIOU-TENG; YU, YUNG-LUNG; LIN, KO-TING; CHEN, JEN-NI; CHANG, WEI-JUNG; WEI, CHYOU-WEI

    2015-01-01

    Acetaminophen (APAP) is a widely used analgesic and antipyretic drug. Generally, the therapeutic dose of APAP is clinically safe, however, high doses of APAP can cause acute liver and kidney injury. Therefore, the majority of previous studies have focussed on elucidating the mechanisms of APAP-induced hepatotoxicity and nephrotoxicity, in addition to examining ways to treat these conditions in clinical cases. However, few studies have reported APAP-induced intoxication in human stem cells. Stem cells are important in cell proliferation, differentiation and repair during human development, particularly during fetal and child development. At present, whether APAP causes cytotoxic effects in human stem cells remains to be elucidated, therefore, the present study aimed to investigate the cellular effects of APAP treatment in human stem cells. The results of the present study revealed that high-dose APAP induced more marked cytotoxic effects in human mesenchymal stem cells (hMSCs) than in renal tubular cells. In addition, increased levels of hydrogen peroxide (H2O2), phosphorylation of c-Jun N-terminal kinase and p38, and activation of caspase-9/-3 cascade were observed in the APAP-treated hMSCs. By contrast, antioxidants, including vitamin C reduced APAP-induced augmentations in H2O2 levels, but did not inhibit the APAP-induced cytotoxic effects in the hMSCs. These results suggested that high doses of APAP may cause serious damage towards hMSCs. PMID:26096646

  8. Activation of mesenchymal stem cells by macrophages promotes tumor progression through immune suppressive effects

    PubMed Central

    Jia, Xiao-hua; Feng, Guo-wei; Wang, Zhong-liang; Du, Yang; Shen, Chen; Hui, Hui; Peng, Dong; Li, Zong-jin; Kong, De-ling; Tian, Jie

    2016-01-01

    Cancer development and progression is linked to tumor-associated macrophages (TAMs). Distinct TAMs subsets perform either protective or pathogenic effects in cancer. A protective role in carcinogenesis has been described for M1 macrophages, which activate antitumor mechanisms. By comparison, TAMs isolated from solid and metastatic tumors have a suppressive M2-like phenotype, which could support multiple aspects of tumor progression. Currently, it has not been clearly understood how macrophages in tumor-associated stroma could be hijacked to support tumor growth. Mesenchymal stem cells (MSCs) actively interact with components of the innate immune system and display both anti-inflammatory and pro-inflammatory effects. Here, we tested whether MSCs could favor the tumor to escape from immunologic surveillance in the presence of M1 macrophages. We found that MSCs educated by M1 condition medium (cMSCs) possessed a greatly enhanced ability in promoting tumor growth in vivo. Examination of cytokines/chemokines showed that the cMSCs acquired a regulatory profile, which expressed high levels of iNOS and MCP1. Consistent with an elevated MCP1 expression in cMSCs, the tumor-promoting effect of the cMSCs depended on MCP1 mediated macrophage recruitment to tumor sites. Furthermore, IL-6 secreted by the cMSCs could polarize infiltrated TAMs into M2-like macrophages. Therefore, when macrophages changed into M1 pro-inflammation type in tumor microenvironment, the MSCs would act as poor sensors and switchers to accelerate tumor growth. PMID:26988913

  9. ΔNp63 promotes stem cell activity in mammary gland development and basal-like breast cancer by enhancing Fzd7 expression and Wnt signalling.

    PubMed

    Chakrabarti, Rumela; Wei, Yong; Hwang, Julie; Hang, Xiang; Andres Blanco, Mario; Choudhury, Abrar; Tiede, Benjamin; Romano, Rose-Anne; DeCoste, Christina; Mercatali, Laura; Ibrahim, Toni; Amadori, Dino; Kannan, Nagarajan; Eaves, Connie J; Sinha, Satrajit; Kang, Yibin

    2014-10-01

    Emerging evidence suggests that cancer is populated and maintained by tumour-initiating cells (TICs) with stem-like properties similar to those of adult tissue stem cells. Despite recent advances, the molecular regulatory mechanisms that may be shared between normal and malignant stem cells remain poorly understood. Here we show that the ΔNp63 isoform of the Trp63 transcription factor promotes normal mammary stem cell (MaSC) activity by increasing the expression of the Wnt receptor Fzd7, thereby enhancing Wnt signalling. Importantly, Fzd7-dependent enhancement of Wnt signalling by ΔNp63 also governs tumour-initiating activity of the basal subtype of breast cancer. These findings establish ΔNp63 as a key regulator of stem cells in both normal and malignant mammary tissues and provide direct evidence that breast cancer TICs and normal MaSCs share common regulatory mechanisms.

  10. Stem cell aging

    PubMed Central

    Muller-Sieburg, Christa; Sieburg, Hans B.

    2009-01-01

    The question whether stem cells age remains an enigma. Traditionally, aging was thought to change the properties of hematopoietic stem cells (HSC). We discuss here a new model of stem cell aging that challenges this view. It is now well-established that the HSC compartment is heterogeneous, consisting of epigenetically fixed subpopulations of HSC that differ in self-renewal and differentiation capacity. New data show that the representation of these HSC subsets changes during aging. HSC that generate lymphocyte-rich progeny are depleted, while myeloid-biased HSC are enriched in the aged HSC compartment. Myeloid-biased HSC, even when isolated from young donors, have most of the characteristics that had been attributed to aged HSC. Thus, the distinct behavior of the HSC isolated from aged hosts is due to the accumulation of myeloid-biased HSC. By extension this means that the properties of individual HSC are not substantially changed during the lifespan of the organism and that aged hosts do not contain many aged HSC. Myeloid-biased HSC give rise to mature cells slowly but contribute for a long time to peripheral hematopoiesis. We propose that such slow, “lazy” HSC are less likely to be transformed and therefore may safely sustain hematopoiesis for a long time. PMID:19066464

  11. Stacking the DEK: from chromatin topology to cancer stem cells.

    PubMed

    Privette Vinnedge, Lisa M; Kappes, Ferdinand; Nassar, Nicolas; Wells, Susanne I

    2013-01-01

    Stem cells are essential for development and tissue maintenance and display molecular markers and functions distinct from those of differentiated cell types in a given tissue. Malignant cells that exhibit stem cell-like activities have been detected in many types of cancers and have been implicated in cancer recurrence and drug resistance. Normal stem cells and cancer stem cells have striking commonalities, including shared cell surface markers and signal transduction pathways responsible for regulating quiescence vs. proliferation, self-renewal, pluripotency and differentiation. As the search continues for markers that distinguish between stem cells, progenitor cells and cancer stem cells, growing evidence suggests that a unique chromatin-associated protein called DEK may confer stem cell-like qualities. Here, we briefly describe current knowledge regarding stem and progenitor cells. We then focus on new findings that implicate DEK as a regulator of stem and progenitor cell qualities, potentially through its unusual functions in the regulation of local or global chromatin organization.

  12. Integrated Analysis of Contractile Kinetics, Force Generation, and Electrical Activity in Single Human Stem Cell-Derived Cardiomyocytes

    PubMed Central

    Kijlstra, Jan David; Hu, Dongjian; Mittal, Nikhil; Kausel, Eduardo; van der Meer, Peter; Garakani, Arman; Domian, Ibrahim J.

    2015-01-01

    Summary The quantitative analysis of cardiomyocyte function is essential for stem cell-based approaches for the in vitro study of human cardiac physiology and pathophysiology. We present a method to comprehensively assess the function of single human pluripotent stem cell-derived cardiomyocyte (hPSC-CMs) through simultaneous quantitative analysis of contraction kinetics, force generation, and electrical activity. We demonstrate that statistical analysis of movies of contracting hPSC-CMs can be used to quantify changes in cellular morphology over time and compute contractile kinetics. Using a biomechanical model that incorporates substrate stiffness, we calculate cardiomyocyte force generation at single-cell resolution and validate this approach with conventional traction force microscopy. The addition of fluorescent calcium indicators or membrane potential dyes allows the simultaneous analysis of contractility and calcium handling or action potential morphology. Accordingly, our approach has the potential for broad application in the study of cardiac disease, drug discovery, and cardiotoxicity screening. PMID:26626178

  13. Statins and stem cell modulation.

    PubMed

    Xu, Hui; Yang, Yue-Jin; Yang, Tao; Qian, Hai-Yan

    2013-01-01

    Stem cell-based therapy is a promising option for the treatment of ischemic heart diseases. As to a successful stem cell-based therapy, one of the most important issues is that the stable engraftment and survival of implanted stem cells in cardiac microenvironment. There are evidences suggest that pharmacological treatment devoted to regulate stem cell function might represent a potential new therapeutic strategy and are drawing nearer to becoming a part of treatment in clinical settings. Statins could exert cholesterol-independent or pleiotropic effects to cardiovascular system. Recent studies have shown that statins could modulate the biological characteristics and function of various stem cells, thus could be an effective method to facilitate stem cell therapy. This review will focus on statins and their modulation effects on various stem cells.

  14. Mesenchymal stem cell like (MSCl) cells generated from human embryonic stem cells support pluripotent cell growth

    SciTech Connect

    Varga, Nora; Vereb, Zoltan; Rajnavoelgyi, Eva; Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs; Apati, Agota

    2011-10-28

    Highlights: Black-Right-Pointing-Pointer MSC like cells were derived from hESC by a simple and reproducible method. Black-Right-Pointing-Pointer Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. Black-Right-Pointing-Pointer MSCl cells as feeder cells support the undifferentiated growth of hESC. -- Abstract: Mesenchymal stem cell like (MSCl) cells were generated from human embryonic stem cells (hESC) through embryoid body formation, and isolated by adherence to plastic surface. MSCl cell lines could be propagated without changes in morphological or functional characteristics for more than 15 passages. These cells, as well as their fluorescent protein expressing stable derivatives, efficiently supported the growth of undifferentiated human embryonic stem cells as feeder cells. The MSCl cells did not express the embryonic (Oct4, Nanog, ABCG2, PODXL, or SSEA4), or hematopoietic (CD34, CD45, CD14, CD133, HLA-DR) stem cell markers, while were positive for the characteristic cell surface markers of MSCs (CD44, CD73, CD90, CD105). MSCl cells could be differentiated toward osteogenic, chondrogenic or adipogenic directions and exhibited significant inhibition of mitogen-activated lymphocyte proliferation, and thus presented immunosuppressive features. We suggest that cultured MSCl cells can properly model human MSCs and be applied as efficient feeders in hESC cultures.

  15. Ovarian cancer stem cells enrichment.

    PubMed

    Yang, Lijuan; Lai, Dongmei

    2013-01-01

    The concept of cancer stem cells (CSCs) provides a new paradigm for understanding cancer biology. Cancer stem cells are defined as a minority of cancer cells with stem cell properties responsible for maintenance and growth of tumors. The targeting of CSCs is a potential therapeutic strategy to combat ovarian cancer. Ovarian epithelial cancer cells cultured in serum-free medium can form sphere cells. These sphere cells may be enriched for cancer stem cells (CSCs). The isolation of sphere cells from solid tumors is an important technique in studying cancer cell biology. Here we describe the isolation of sphere cells from primary ovarian cancer tissue, ascites fluid, and the cancer cell line SKOV3 with stem cell selection medium. PMID:23913228

  16. mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

    PubMed

    Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

    2015-02-01

    Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration. PMID:25609845

  17. mTOR signaling promotes stem cell activation via counterbalancing BMP-mediated suppression during hair regeneration.

    PubMed

    Deng, Zhili; Lei, Xiaohua; Zhang, Xudong; Zhang, Huishan; Liu, Shuang; Chen, Qi; Hu, Huimin; Wang, Xinyue; Ning, Lina; Cao, Yujing; Zhao, Tongbiao; Zhou, Jiaxi; Chen, Ting; Duan, Enkui

    2015-02-01

    Hair follicles (HFs) undergo cycles of degeneration (catagen), rest (telogen), and regeneration (anagen) phases. Anagen begins when the hair follicle stem cells (HFSCs) obtain sufficient activation cues to overcome suppressive signals, mainly the BMP pathway, from their niche cells. Here, we unveil that mTOR complex 1 (mTORC1) signaling is activated in HFSCs, which coincides with the HFSC activation at the telogen-to-anagen transition. By using both an inducible conditional gene targeting strategy and a pharmacological inhibition method to ablate or inhibit mTOR signaling in adult skin epithelium before anagen initiation, we demonstrate that HFs that cannot respond to mTOR signaling display significantly delayed HFSC activation and extended telogen. Unexpectedly, BMP signaling activity is dramatically prolonged in mTOR signaling-deficient HFs. Through both gain- and loss-of-function studies in vitro, we show that mTORC1 signaling negatively affects BMP signaling, which serves as a main mechanism whereby mTORC1 signaling facilitates HFSC activation. Indeed, in vivo suppression of BMP by its antagonist Noggin rescues the HFSC activation defect in mTORC1-null skin. Our findings reveal a critical role for mTOR signaling in regulating stem cell activation through counterbalancing BMP-mediated repression during hair regeneration.

  18. Chronic activation of pattern recognition receptors suppresses brown adipogenesis of multipotent mesodermal stem cells and brown pre-adipocytes.

    PubMed

    Bae, Jiyoung; Chen, Jiangang; Zhao, Ling

    2015-06-01

    Brown adipose tissue (BAT) holds promise to combat obesity through energy-spending, non-shivering thermogenesis. Understanding of regulation of BAT development can lead to novel strategies to increase BAT mass and function for obesity treatment and prevention. Here, we report the effects of chronic activation of PRR on brown adipogenesis of multipotent mesodermal stem C3H10T1/2 cells and immortalized brown pre-adipocytes from the classical interscapular BAT of mice. Activation of NOD1, TLR4, or TLR2 by their respective synthetic ligand suppressed brown marker gene expression and lipid accumulation during differentiation of brown-like adipocytes of C3H10T1/2. Activation of the PRR only during the commitment was sufficient to suppress the differentiation. PRR activation suppressed PGC-1α mRNA, but induced PRDM16 mRNA at the commitment. Consistently, PRR activation suppressed the differentiation of immortalized brown pre-adipocytes. Activation of PRR induced NF-κB activation in both cells, which correlated with their abilities to suppress PPARγ transactivation, a critical event for brown adipogenesis. Taken together, our results demonstrate that chronic PRR activation suppressed brown adipogenesis of multipotent mesodermal stem cells and brown pre-adipocytes, possibly through suppression of PPARγ transactivation. The results suggest that anti- inflammatory therapies targeting PRRs may be beneficial for the BAT development.

  19. Ricinus communis L. stem bark extracts regulate ovarian cell functions and secretory activity and their response to Luteinising hormone.

    PubMed

    Nath, S; Kadasi, A; Grossmann, R; Sirotkin, A V; Kolesarova, A; Talukdar, A D; Choudhury, M D

    2015-01-01

    Ricinus communis L. has ethnopharmacological contraceptive reputation but its stem bark has unexplored mechanisms of action in female reproductive system. In the present study, the effect of methanolic and aqueous extracts from the stem bark of the plant was examined on basic porcine ovarian granulosa cell functions and its response to Luteinising hormone (LH)-the upstream hormonal regulator. Systemic treatment of methanolic and aqueous extracts stimulated cell proliferation (proliferating cell nuclear antigen, PCNA) and also promoted cell apoptosis (caspase-3). Aqueous extract has inverted the stimulatory effect of LH on PCNA but not on caspase-3. Methanolic extract stimulated as well as inhibited progesterone release and stimulated testosterone secretion. Whereas aqueous extract inhibited both steroid releases and suppressed the stimulatory effect of LH on progesterone release and promoted the inhibitory effect of LH on testosterone release. In conclusion, the present study unveils the mechanism of action of R. communis stem bark in in vitro condition. These suggest its possible contraceptive efficacy by exerting its regulatory role over LH and on basic ovarian cell functions and secretion activity. PMID:26311247

  20. Immunohistochemical evaluation of stem cell markers and signal transducer and activator of transcription 6 (STAT6) in solitary fibrous tumors.

    PubMed

    Wang, Chengyan; Qi, Yan; Liu, Ruixue; Lan, Jiaojiao; Zhou, Yang; Ju, Xinxin; Chen, Dongdong; Zou, Hong; Li, Shugang; Hu, Jianming; Zhao, Jin; Shen, Yaoyuan; Sun, Zhenzhu; Pang, Lijuan; Li, Feng

    2015-01-01

    Solitary fibrous tumors (SFT) are fibroblastic, ubiquitous mesenchymal tumors. Although several SFT studies have been conducted, the cell of origin of SFT remains controversial and reliable diagnostic markers are needed for SFT identification for proper prognosis and therapeutics. To analyze the immunophenotype of SFT for the identification of specific diagnostic markers and the cell of origin of this tumor, we performed an immunohistochemical study of stem cell markers [aldehyde dehydrogenase 1 (ALDH1), CD29, CD44, CD133, and nestin] and signal transducer and activator of transcription 6 (STAT6) in 18 cases of SFT. The results demonstrated that ALDH1 was present in 16 cases (16/18), STAT6 in 13 cases (13/18), CD44 in 8 cases (8/18), and CD29 in 1 case (1/18), whereas CD133 and nestin were absent in all cases (0/18). Our results indicate that combination with ALDH1 and STAT6 can improve the diagnostic value of CD34 for SFT. The immunohistochemical findings for stem cell surface markers indicate that SFT may originate from stem cells and that ALDH1 plays an important role in the development of SFT. PMID:26617768

  1. Immunohistochemical evaluation of stem cell markers and signal transducer and activator of transcription 6 (STAT6) in solitary fibrous tumors.

    PubMed

    Wang, Chengyan; Qi, Yan; Liu, Ruixue; Lan, Jiaojiao; Zhou, Yang; Ju, Xinxin; Chen, Dongdong; Zou, Hong; Li, Shugang; Hu, Jianming; Zhao, Jin; Shen, Yaoyuan; Sun, Zhenzhu; Pang, Lijuan; Li, Feng

    2015-01-01

    Solitary fibrous tumors (SFT) are fibroblastic, ubiquitous mesenchymal tumors. Although several SFT studies have been conducted, the cell of origin of SFT remains controversial and reliable diagnostic markers are needed for SFT identification for proper prognosis and therapeutics. To analyze the immunophenotype of SFT for the identification of specific diagnostic markers and the cell of origin of this tumor, we performed an immunohistochemical study of stem cell markers [aldehyde dehydrogenase 1 (ALDH1), CD29, CD44, CD133, and nestin] and signal transducer and activator of transcription 6 (STAT6) in 18 cases of SFT. The results demonstrated that ALDH1 was present in 16 cases (16/18), STAT6 in 13 cases (13/18), CD44 in 8 cases (8/18), and CD29 in 1 case (1/18), whereas CD133 and nestin were absent in all cases (0/18). Our results indicate that combination with ALDH1 and STAT6 can improve the diagnostic value of CD34 for SFT. The immunohistochemical findings for stem cell surface markers indicate that SFT may originate from stem cells and that ALDH1 plays an important role in the development of SFT.

  2. Ricinus communis L. stem bark extracts regulate ovarian cell functions and secretory activity and their response to Luteinising hormone.

    PubMed

    Nath, S; Kadasi, A; Grossmann, R; Sirotkin, A V; Kolesarova, A; Talukdar, A D; Choudhury, M D

    2015-01-01

    Ricinus communis L. has ethnopharmacological contraceptive reputation but its stem bark has unexplored mechanisms of action in female reproductive system. In the present study, the effect of methanolic and aqueous extracts from the stem bark of the plant was examined on basic porcine ovarian granulosa cell functions and its response to Luteinising hormone (LH)-the upstream hormonal regulator. Systemic treatment of methanolic and aqueous extracts stimulated cell proliferation (proliferating cell nuclear antigen, PCNA) and also promoted cell apoptosis (caspase-3). Aqueous extract has inverted the stimulatory effect of LH on PCNA but not on caspase-3. Methanolic extract stimulated as well as inhibited progesterone release and stimulated testosterone secretion. Whereas aqueous extract inhibited both steroid releases and suppressed the stimulatory effect of LH on progesterone release and promoted the inhibitory effect of LH on testosterone release. In conclusion, the present study unveils the mechanism of action of R. communis stem bark in in vitro condition. These suggest its possible contraceptive efficacy by exerting its regulatory role over LH and on basic ovarian cell functions and secretion activity.

  3. Myocilin Stimulates Osteogenic Differentiation of Mesenchymal Stem Cells through Mitogen-activated Protein Kinase Signaling*

    PubMed Central

    Kwon, Heung Sun; Johnson, Thomas V.; Tomarev, Stanislav I.

    2013-01-01

    Myocilin is a secreted glycoprotein that is expressed in ocular and non-ocular tissues. Mutations in the MYOCILIN gene may lead to juvenile- and adult-onset primary open-angle glaucoma. Here we report that myocilin is expressed in bone marrow-derived mesenchymal stem cells (MSCs) and plays a role in their differentiation into osteoblasts in vitro and in osteogenesis in vivo. Expression of myocilin was detected in MSCs derived from mouse, rat, and human bone marrow, with human MSCs exhibiting the highest level of myocilin expression. Expression of myocilin rose during the course of human MSC differentiation into osteoblasts but not into adipocytes, and treatment with exogenous myocilin further enhanced osteogenesis. MSCs derived from Myoc-null mice had a reduced ability to differentiate into the osteoblastic lineage, which was partially rescued by exogenous extracellular myocilin treatment. Myocilin also stimulated osteogenic differentiation of wild-type MSCs, which was associated with activation of the p38, Erk1/2, and JNK MAP kinase signaling pathways as well as up-regulated expression of the osteogenic transcription factors Runx2 and Dlx5. Finally, cortical bone thickness and trabecular volume, as well as the expression level of osteopontin, a known factor of bone remodeling and osteoblast differentiation, were reduced dramatically in the femurs of Myoc-null mice compared with wild-type mice. These data suggest that myocilin should be considered as a target for improving the bone regenerative potential of MSCs and may identify a new role for myocilin in bone formation and/or maintenance in vivo. PMID:23629661

  4. The secretome of myocardial telocytes modulates the activity of cardiac stem cells.

    PubMed

    Albulescu, Radu; Tanase, Cristiana; Codrici, Elena; Popescu, Daniela I; Cretoiu, Sanda M; Popescu, Laurentiu M

    2015-08-01

    Telocytes (TCs) are interstitial cells that are present in numerous organs, including the heart interstitial space and cardiac stem cell niche. TCs are completely different from fibroblasts. TCs release extracellular vesicles that may interact with cardiac stem cells (CSCs) via paracrine effects. Data on the secretory profile of TCs and the bidirectional shuttle vesicular signalling mechanism between TCs and CSCs are scarce. We aimed to characterize and understand the in vitro effect of the TC secretome on CSC fate. Therefore, we studied the protein secretory profile using supernatants from mouse cultured cardiac TCs. We also performed a comparative secretome analysis using supernatants from rat cultured cardiac TCs, a pure CSC line and TCs-CSCs in co-culture using (i) high-sensitivity on-chip electrophoresis, (ii) surface-enhanced laser desorption/ionization time-of-flight mass spectrometry and (iii) multiplex analysis by Luminex-xMAP. We identified several highly expressed molecules in the mouse cardiac TC secretory profile: interleukin (IL)-6, VEGF, macrophage inflammatory protein 1α (MIP-1α), MIP-2 and MCP-1, which are also present in the proteome of rat cardiac TCs. In addition, rat cardiac TCs secrete a slightly greater number of cytokines, IL-2, IL-10, IL-13 and some chemokines like, GRO-KC. We found that VEGF, IL-6 and some chemokines (all stimulated by IL-6 signalling) are secreted by cardiac TCs and overexpressed in co-cultures with CSCs. The expression levels of MIP-2 and MIP-1α increased twofold and fourfold, respectively, when TCs were co-cultured with CSCs, while the expression of IL-2 did not significantly differ between TCs and CSCs in mono culture and significantly decreased (twofold) in the co-culture system. These data suggest that the TC secretome plays a modulatory role in stem cell proliferation and differentiation. PMID:26176909

  5. The secretome of myocardial telocytes modulates the activity of cardiac stem cells

    PubMed Central

    Albulescu, Radu; Tanase, Cristiana; Codrici, Elena; Popescu, Daniela I; Cretoiu, Sanda M; Popescu, Laurentiu M

    2015-01-01

    Telocytes (TCs) are interstitial cells that are present in numerous organs, including the heart interstitial space and cardiac stem cell niche. TCs are completely different from fibroblasts. TCs release extracellular vesicles that may interact with cardiac stem cells (CSCs) via paracrine effects. Data on the secretory profile of TCs and the bidirectional shuttle vesicular signalling mechanism between TCs and CSCs are scarce. We aimed to characterize and understand the in vitro effect of the TC secretome on CSC fate. Therefore, we studied the protein secretory profile using supernatants from mouse cultured cardiac TCs. We also performed a comparative secretome analysis using supernatants from rat cultured cardiac TCs, a pure CSC line and TCs-CSCs in co-culture using (i) high-sensitivity on-chip electrophoresis, (ii) surface-enhanced laser desorption/ionization time-of-flight mass spectrometry and (iii) multiplex analysis by Luminex-xMAP. We identified several highly expressed molecules in the mouse cardiac TC secretory profile: interleukin (IL)-6, VEGF, macrophage inflammatory protein 1α (MIP-1α), MIP-2 and MCP-1, which are also present in the proteome of rat cardiac TCs. In addition, rat cardiac TCs secrete a slightly greater number of cytokines, IL-2, IL-10, IL-13 and some chemokines like, GRO-KC. We found that VEGF, IL-6 and some chemokines (all stimulated by IL-6 signalling) are secreted by cardiac TCs and overexpressed in co-cultures with CSCs. The expression levels of MIP-2 and MIP-1α increased twofold and fourfold, respectively, when TCs were co-cultured with CSCs, while the expression of IL-2 did not significantly differ between TCs and CSCs in mono culture and significantly decreased (twofold) in the co-culture system. These data suggest that the TC secretome plays a modulatory role in stem cell proliferation and differentiation. PMID:26176909

  6. Intraventricular injections of mesenchymal stem cells activate endogenous functional remyelination in a chronic demyelinating murine model

    PubMed Central

    Cruz-Martinez, P; González-Granero, S; Molina-Navarro, M M; Pacheco-Torres, J; García-Verdugo, J M; Geijo-Barrientos, E; Jones, J; Martinez, S

    2016-01-01

    Current treatments for demyelinating diseases are generally only capable of ameliorating the symptoms, with little to no effect in decreasing myelin loss nor promoting functional recovery. Mesenchymal stem cells (MSCs) have been shown by many researchers to be a potential therapeutic tool in treating various neurodegenerative diseases, including demyelinating disorders. However, in the majority of the cases, the effect was only observed locally, in the area surrounding the graft. Thus, in order to achieve general remyelination in various brain structures simultaneously, bone marrow-derived MSCs were transplanted into the lateral ventricles (LVs) of the cuprizone murine model. In this manner, the cells may secrete soluble factors into the cerebrospinal fluid (CSF) and boost the endogenous oligodendrogenic potential of the subventricular zone (SVZ). As a result, oligodendrocyte progenitor cells (OPCs) were recruited within the corpus callosum (CC) over time, correlating with an increased myelin content. Electrophysiological studies, together with electron microscopy (EM) analysis, indicated that the newly formed myelin correctly enveloped the demyelinated axons and increased signal transduction through the CC. Moreover, increased neural stem progenitor cell (NSPC) proliferation was observed in the SVZ, possibly due to the tropic factors released by the MSCs. In conclusion, the findings of this study revealed that intraventricular injections of MSCs is a feasible method to elicit a paracrine effect in the oligodendrogenic niche of the SVZ, which is prone to respond to the factors secreted into the CSF and therefore promoting oligodendrogenesis and functional remyelination. PMID:27171265

  7. Efficient Gene Editing in Pluripotent Stem Cells by Bacterial Injection of Transcription Activator-Like Effector Nuclease Proteins

    PubMed Central

    Jia, Jingyue; Bai, Fang; Jin, Yongxin; Santostefano, Katherine E.; Ha, Un-Hwan; Wu, Donghai

    2015-01-01

    The type III secretion system (T3SS) of Pseudomonas aeruginosa is a powerful tool for direct protein delivery into mammalian cells and has successfully been used to deliver various exogenous proteins into mammalian cells. In the present study, transcription activator-like effector nuclease (TALEN) proteins have been efficiently delivered using the P. aeruginosa T3SS into mouse embryonic stem cells (mESCs), human ESCs (hESCs), and human induced pluripotent stem cells (hiPSCs) for genome editing. This bacterial delivery system offers an alternative method of TALEN delivery that is highly efficient in cleavage of the chromosomal target and presumably safer by avoiding plasmid DNA introduction. We combined the method of bacterial T3SS-mediated TALEN protein injection and transfection of an oligonucleotide template to effectively generate precise genetic modifications in the stem cells. Initially, we efficiently edited a single-base in the gfp gene of a mESC line to silence green fluorescent protein (GFP) production. The resulting GFP-negative mESC was cloned from a single cell and subsequently mutated back to a GFP-positive mESC line. Using the same approach, the gfp gene was also effectively knocked out in hESCs. In addition, a defined single-base edition was effectively introduced into the X-chromosome-linked HPRT1 gene in hiPSCs, generating an in vitro model of Lesch-Nyhan syndrome. T3SS-mediated TALEN protein delivery provides a highly efficient alternative for introducing precise gene editing within pluripotent stem cells for the purpose of disease genotype-phenotype relationship studies and cellular replacement therapies. Significance The present study describes a novel and powerful tool for the delivery of the genome editing enzyme transcription activator-like effector nuclease (TALEN) directly into pluripotent stem cells (PSCs), achieving desired base changes on the genomes of PSCs with high efficiency. This novel approach uses bacteria as a protein delivery

  8. Intracerebral transplantation of adipose-derived mesenchymal stem cells alternatively activates microglia and ameliorates neuropathological deficits in Alzheimer's disease mice.

    PubMed

    Ma, Tuo; Gong, Kai; Ao, Qiang; Yan, Yufang; Song, Bo; Huang, Hongyun; Zhang, Xiufang; Gong, Yandao

    2013-01-01

    Recent studies suggest that transplantation of mesenchymal stem cells might have therapeutic effects in preventing pathogenesis of several neurodegenerative disorders. Adipose-derived mesenchymal stem cells (ADSCs) are a promising new cell source for regenerative therapy. However, whether transplantation of ADSCs could actually ameliorate the neuropathological deficits in Alzheimer's disease (AD) and the mechanisms involved has not yet been established. Here, we evaluated the therapeutic effects of intracerebral ADSC transplantation on AD pathology and spatial learning/memory of APP/PS1 double transgenic AD model mice. Results showed that ADSC transplantation dramatically reduced β-amyloid (Aβ) peptide deposition and significantly restored the learning/memory function in APP/PS1 transgenic mice. It was observed that in both regions of the hippocampus and the cortex there were more activated microglia, which preferentially surrounded and infiltrated into plaques after ADSC transplantation. The activated microglia exhibited an alternatively activated phenotype, as indicated by their decreased expression levels of proinflammatory factors and elevated expression levels of alternative activation markers, as well as Aβ-degrading enzymes. In conclusion, ADSC transplantation could modulate microglial activation in AD mice, mitigate AD symptoms, and alleviate cognitive decline, all of which suggest ADSC transplantation as a promising choice for AD therapy. This manuscript is published as part of the International Association of Neurorestoratology (IANR) supplement issue of Cell Transplantation.

  9. Klotho, stem cells, and aging

    PubMed Central

    Bian, Ao; Neyra, Javier A; Zhan, Ming; Hu, Ming Chang

    2015-01-01

    Aging is an inevitable and progressive biological process involving dysfunction and eventually destruction of every tissue and organ. This process is driven by a tightly regulated and complex interplay between genetic and acquired factors. Klotho is an antiaging gene encoding a single-pass transmembrane protein, klotho, which serves as an aging suppressor through a wide variety of mechanisms, such as antioxidation, antisenescence, antiautophagy, and modulation of many signaling pathways, including insulin-like growth factor and Wnt. Klotho deficiency activates Wnt expression and activity contributing to senescence and depletion of stem cells, which consequently triggers tissue atrophy and fibrosis. In contrast, the klotho protein was shown to suppress Wnt-signaling transduction, and inhibit cell senescence and preserve stem cells. A better understanding of the potential effects of klotho on stem cells could offer novel insights into the cellular and molecular mechanisms of klotho deficiency-related aging and disease. The klotho protein may be a promising therapeutic agent for aging and aging-related disorders. PMID:26346243

  10. Klotho, stem cells, and aging.

    PubMed

    Bian, Ao; Neyra, Javier A; Zhan, Ming; Hu, Ming Chang

    2015-01-01

    Aging is an inevitable and progressive biological process involving dysfunction and eventually destruction of every tissue and organ. This process is driven by a tightly regulated and complex interplay between genetic and acquired factors. Klotho is an antiaging gene encoding a single-pass transmembrane protein, klotho, which serves as an aging suppressor through a wide variety of mechanisms, such as antioxidation, antisenescence, antiautophagy, and modulation of many signaling pathways, including insulin-like growth factor and Wnt. Klotho deficiency activates Wnt expression and activity contributing to senescence and depletion of stem cells, which consequently triggers tissue atrophy and fibrosis. In contrast, the klotho protein was shown to suppress Wnt-signaling transduction, and inhibit cell senescence and preserve stem cells. A better understanding of the potential effects of klotho on stem cells could offer novel insights into the cellular and molecular mechanisms of klotho deficiency-related aging and disease. The klotho protein may be a promising therapeutic agent for aging and aging-related disorders. PMID:26346243

  11. Klotho, stem cells, and aging.

    PubMed

    Bian, Ao; Neyra, Javier A; Zhan, Ming; Hu, Ming Chang

    2015-01-01

    Aging is an inevitable and progressive biological process involving dysfunction and eventually destruction of every tissue and organ. This process is driven by a tightly regulated and complex interplay between genetic and acquired factors. Klotho is an antiaging gene encoding a single-pass transmembrane protein, klotho, which serves as an aging suppressor through a wide variety of mechanisms, such as antioxidation, antisenescence, antiautophagy, and modulation of many signaling pathways, including insulin-like growth factor and Wnt. Klotho deficiency activates Wnt expression and activity contributing to senescence and depletion of stem cells, which consequently triggers tissue atrophy and fibrosis. In contrast, the klotho protein was shown to suppress Wnt-signaling transduction, and inhibit cell senescence and preserve stem cells. A better understanding of the potential effects of klotho on stem cells could offer novel insights into the cellular and molecular mechanisms of klotho deficiency-related aging and disease. The klotho protein may be a promising therapeutic agent for aging and aging-related disorders.

  12. Breast Cancer Stem Cells

    PubMed Central

    Velasco-Velázquez, Marco A.; Homsi, Nora; De La Fuente, Marisol; Pestell, Richard G.

    2012-01-01

    Breast cancer stem cells (BCSCs) constitute a subpopulation of tumor cells that express stem cell-associated markers and have a high capacity for tumor generation in vivo. Identification of BCSCs from tumor samples or breast cancer cell lines has been based mainly on CD44+/CD24−/low or ALDH+ phenotypes. BCSCs isolation has allowed the analysis of the molecular mechanisms involved in their origin, self-renewal, differentiation into tumor cells, resistance to radiation therapy and chemotherapy, and invasiveness and metastatic ability. Molecular genetic analysis using knockout animals and inducible transgenics have identified NF-κB, c-Jun, p21CIP1, and Forkhead-like-protein Dach1 in BCSC expansion and fate. Clinical analyses of BCSCs in breast tumors have found a correlation between the proportion of BCSCs and poor prognosis. Therefore, new therapies that specifically target BCSCs are an urgent need. We summarize recent evidence that partially explain the biological characteristics of BCSCs. PMID:22249027

  13. Breast cancer stem cells and radiation

    NASA Astrophysics Data System (ADS)

    Phillips, Tiffany Marie

    2007-12-01

    The present studies explore the response of breast cancer stem cells (BCSC's) to radiation and the implications for clinical cancer treatment. Current cancer therapy eliminates bulky tumor mass but may fail to eradicate a critical tumor initiating cell population termed "cancer stem cells". These cells are potentially responsible for tumor formation, metastasis, and recurrence. Recently cancer stem cells have been prospectively identified in various malignancies, including breast cancer. The breast cancer stem cell has been identified by the surface markers CD44+/CD24 -(low). In vitro mammosphere cultures allow for the enrichment of the cancer stem cell population and were utilized in order to study differential characteristics of BCSC's. Initial studies found that BCSC's display increased radiation resistance as compared to other non-stem tumor cells. This resistance was accompanied by decreased H2AX phosphorylation, decreased reactive oxygen species formation, and increased phosphorylation of the checkpoint protein Chk1. These studies suggest differential DNA damage and repair within the BCSC population. Studies then examined the consequences of fractionated radiation on the BCSC population and found a two-fold increase in BCSC's following 5 x 3Gy. This observation begins to tie cancer stem cell self-renewal to the clinical stem cell phenomenon of accelerated repopulation. Accelerated repopulation is observed when treatment gaps increase between sequential fractions of radiotherapy and may be due to cancer stem cell symmetric self-renewal. The balance between asymmetric and symmetric stem cell division is vital for proper maintenance; deregulation is likely linked to cancer initiation and progression. The developmental Notch-1 pathway was found to regulate BCSC division. Over-expressing the constitutively active Notch-1-ICD in MCF7 cells produced an increase in the BCSC population. Additionally, radiation was observed to increase the expression of the Notch-1

  14. Biomarker-specific conjugated nanopolyplexes for the active coloring of stem-like cancer cells

    NASA Astrophysics Data System (ADS)

    Hong, Yoochan; Lee, Eugene; Choi, Jihye; Haam, Seungjoo; Suh, Jin-Suck; Yang, Jaemoon

    2016-06-01

    Stem-like cancer cells possess intrinsic features and their CD44 regulate redox balance in cancer cells to survive under stress conditions. Thus, we have fabricated biomarker-specific conjugated polyplexes using CD44-targetable hyaluronic acid and redox-sensible polyaniline based on a nanoemulsion method. For the most sensitive recognition of the cellular redox at a single nanoparticle scale, a nano-scattering spectrum imaging analyzer system was introduced. The conjugated polyplexes showed a specific targeting ability toward CD44-expressing cancer cells as well as a dramatic change in its color, which depended on the redox potential in the light-scattered images. Therefore, these polyaniline-based conjugated polyplexes as well as analytical processes that include light-scattering imaging and measurements of scattering spectra, clearly establish a systematic method for the detection and monitoring of cancer microenvironments.

  15. Biomarker-specific conjugated nanopolyplexes for the active coloring of stem-like cancer cells.

    PubMed

    Hong, Yoochan; Lee, Eugene; Choi, Jihye; Haam, Seungjoo; Suh, Jin-Suck; Yang, Jaemoon

    2016-06-01

    Stem-like cancer cells possess intrinsic features and their CD44 regulate redox balance in cancer cells to survive under stress conditions. Thus, we have fabricated biomarker-specific conjugated polyplexes using CD44-targetable hyaluronic acid and redox-sensible polyaniline based on a nanoemulsion method. For the most sensitive recognition of the cellular redox at a single nanoparticle scale, a nano-scattering spectrum imaging analyzer system was introduced. The conjugated polyplexes showed a specific targeting ability toward CD44-expressing cancer cells as well as a dramatic change in its color, which depended on the redox potential in the light-scattered images. Therefore, these polyaniline-based conjugated polyplexes as well as analytical processes that include light-scattering imaging and measurements of scattering spectra, clearly establish a systematic method for the detection and monitoring of cancer microenvironments. PMID:27098318

  16. Pancreatic cancer stem cells

    PubMed Central

    Zhu, Ya-Yun; Yuan, Zhou

    2015-01-01

    Studies are emerging in support of the cancer stem cells (CSCs) theory which considers that a tiny subset of cancer cells is exclusively responsible for the initiation and malignant behavior of a cancer. This cell population, also termed CSCs, possesses the capacity both to self-renew, producing progeny that have the identical tumorigenic potential, and to differentiate into the bulk of cancer cells, helping serve the formation of the tumor entities, which, altogether, build the hierarchically organized structure of a cancer. In this review, we try to articulate the complicated signaling pathways regulating the retention of the characteristics of pancreatic CSCs, and in the wake of which, we seek to offer insights into the CSCs-relevant targeted therapeutics which are, in the meantime, confronted with bigger challenges than ever. PMID:26045976

  17. New activators and inhibitors in the hair cycle clock: targeting stem cells' state of competence.

    PubMed

    Plikus, Maksim V

    2012-05-01

    The timing mechanism of the hair cycle remains poorly understood. However, it has become increasingly clear that the telogen-to-anagen transition is controlled jointly by at least the bone morphogenic protein (BMP), WNT, fibroblast growth factor (FGF), and transforming growth factor (TGF)-β signaling pathways. New research shows that Fgf18 signaling in hair follicle stem cells synergizes BMP-mediated refractivity, whereas Tgf-β2 signaling counterbalances it. Loss of Fgf18 signaling markedly accelerates anagen initiation, whereas loss of Tgf-β2 signaling significantly delays it, supporting key roles for these pathways in hair cycle timekeeping. PMID:22499035

  18. New activators and inhibitors in the hair cycle clock: targeting stem cells' state of competence.

    PubMed

    Plikus, Maksim V

    2012-05-01

    The timing mechanism of the hair cycle remains poorly understood. However, it has become increasingly clear that the telogen-to-anagen transition is controlled jointly by at least the bone morphogenic protein (BMP), WNT, fibroblast growth factor (FGF), and transforming growth factor (TGF)-β signaling pathways. New research shows that Fgf18 signaling in hair follicle stem cells synergizes BMP-mediated refractivity, whereas Tgf-β2 signaling counterbalances it. Loss of Fgf18 signaling markedly accelerates anagen initiation, whereas loss of Tgf-β2 signaling significantly delays it, supporting key roles for these pathways in hair cycle timekeeping.

  19. p21-activated kinase 1 determines stem-like phenotype and sunitinib resistance via NF-κB/IL-6 activation in renal cell carcinoma.

    PubMed

    Zhu, Y; Liu, H; Xu, L; An, H; Liu, W; Liu, Y; Lin, Z; Xu, J

    2015-02-12

    The p21-activated kinase 1 (PAK1), a serine/threonine kinase that orchestrates cytoskeletal remodeling and cell motility, has been shown to function as downstream node for various oncogenic signaling pathways to promote cell proliferation, regulate apoptosis and accelerate mitotic abnormalities, resulting in tumor formation and invasiveness. Although alterations in PAK1 expression and activity have been detected in various human malignancies, its potential biological and clinical significance in renal cell carcinoma (RCC) remains obscure. In this study, we found increased PAK1 and phosphorylated PAK1 levels in tumor tissues according to TNM stage progression. Elevated phosphorylated PAK1 levels associated with progressive features and indicated unfavorable overall survival (OS) as an independent adverse prognosticator for patients with RCC. Moreover, PAK1 kinase activation with constitutive active PAK1 mutant T423E promoted growth, colony formation, migration, invasion and stem-like phenotype of RCC cells, and vice versa, in PAK1 inhibition by PAK1 kinase inactivation with specific PAK1 shRNA, dead kinase PAK1 mutant K299R or allosteric inhibitor IPA3. Stem-like phenotype due to sunitinib administration via increased PAK1 kinase activation could be ameliorated by PAK1 shRNA, PAK1 mutant K299R and IPA3. Furthermore, nuclear factor-κB (NF-κB)/interleukin-6 (IL-6) activation was found to be responsible for PAK1-mediated stem-like phenotype following sunitinib treatment. Both IL-6 neutralizing antibody and IPA3 administration enhanced tumor growth inhibition effect of sunitinib treatment on RCC cells in vitro and in vivo. Our results unraveled that oncogenic activation of PAK1 defines an important mechanism for maintaining stem-like phenotype and sunitinib resistance through NF-κB/IL-6 activation in RCC, lending PAK1-mediated NF-κB/IL-6 activation considerable appeal as novel pharmacological therapeutic targets against sunitinib resistance.

  20. Homeobox B7 promotes the osteogenic differentiation potential of mesenchymal stem cells by activating RUNX2 and transcript of BSP

    PubMed Central

    Gao, Run-Tao; Zhan, Li-Ping; Meng, Cen; Zhang, Ning; Chang, Shi-Min; Yao, Rui; Li, Chong

    2015-01-01

    Mesenchymal stem cells (MSCs) are a reliable cell source for tissue regeneration. However, the molecular mechanisms underlying the directed differentiation of MSCs remain unclear; thus, their use is limited. Here, we investigate HOXB7 function in the osteogenic differentiation potentials of MSCs using stem cells from apical papilla (SCAPs) and bone marrow stem cells (BMSCs). The HOXB7 gene is highly expressed in BMSCs compared with dental tissue-derived MSCs. We found that, in vitro, over-expression of HOXB7 in SCAPs enhanced alkaline phosphatase (ALP) activity and mineralization. HOXB7 over-expression affected the mRNA expression of osteonectin (ON), collagen alpha-2(I) chain (COL1A2), bone sialoprotein (BSP), and osteocalcin (OCN), led to the expression of the key transcription factor, runt-related transcription factor 2 (RUNX2), and promoted SCAP osteogenic differentiation in vitro. The knock-down of HOXB7 inhibited ALP activity, mineralization, and the expression of ON, BSP, COL1A2, OCN, and RUNX2 in BMSCs in vitro. In addition, transplant experiments in nude mice confirmed that SCAP osteogenesis was triggered when HOXB7 was activated. Furthermore, Over-expression of HOXB7 significantly increased the levels of HOXB7 associated with the BSP promoter by ChIP assays. Taken together, these results indicate that HOXB7 enhances SCAP osteogenic differentiation by up-regulating RUNX2 and directly activating transcript of BSP. Thus, the activation of HOXB7 signaling might improve tissue regeneration mediated by MSCs. These results provide insight into the mechanism underlying the directed differentiation of MSCs. PMID:26379836

  1. DNA damage response in adult stem cells.

    PubMed

    Insinga, Alessandra; Cicalese, Angelo; Pelicci, Pier Giuseppe

    2014-04-01

    This review discusses the processes of DNA-damage-response and DNA-damage repair in stem and progenitor cells of several tissues. The long life-span of stem cells suggests that they may respond differently to DNA damage than their downstream progeny and, indeed, studies have begun to elucidate the unique stem cell response mechanisms to DNA damage. Because the DNA damage responses in stem cells and progenitor cells are distinctly different, stem and progenitor cells should be considered as two different entities from this point of view. Hematopoietic and mammary stem cells display a unique DNA-damage response, which involves active inhibition of apoptosis, entry into the cell-cycle, symmetric division, partial DNA repair and maintenance of self-renewal. Each of these biological events depends on the up-regulation of the cell-cycle inhibitor p21. Moreover, inhibition of apoptosis and symmetric stem cell division are the consequence of the down-regulation of the tumor suppressor p53, as a direct result of p21 up-regulation. A deeper understanding of these processes is required before these findings can be translated into human anti-aging and anti-cancer therapies. One needs to clarify and dissect the pathways that control p21 regulation in normal and cancer stem cells and define (a) how p21 blocks p53 functions in stem cells and (b) how p21 promotes DNA repair in stem cells. Is this effect dependent on p21s ability to inhibit p53? Such molecular knowledge may pave the way to methods for maintaining short-term tissue reconstitution while retaining long-term cellular and genomic integrity.

  2. Stem cells and neurodegenerative diseases.

    PubMed

    Hou, LingLing; Hong, Tao

    2008-04-01

    Neurodegenerative diseases are characterized by the neurodegenerative changes or apoptosis of neurons involved in networks, which are important to specific physiological functions. With the development of old-aging society, the incidence of neurodegenerative diseases is on the increase. However, it is difficult to diagnose for most of neurodegenerative diseases. At present, there are too few effective therapies. Advances in stem cell biology have raised the hope and possibility for the therapy of neurodegenerative diseases. Recently, stem cells have been widely attempted to treat neurodegenerative diseases of animal model. Here we review the progress and prospects of various stem cells, including embryonic stem cells, mesenchymal stem cell and neural stem cells and so on, for the treatments of neurodegenerative diseases, such as Parkinson's disease, Alzheimer's disease, Huntington' disease and Amyotrophic lateral sclerosis/Lou Gehrig's disease.

  3. Toward label-free Raman-activated cell sorting of cardiomyocytes derived from human embryonic stem cells

    NASA Astrophysics Data System (ADS)

    Pascut, Flavius C.; Goh, Huey T.; George, Vinoj; Denning, Chris; Notingher, Ioan

    2011-04-01

    Raman micro-spectroscopy (RMS) has been recently proposed for label-free phenotypic identification of human embryonic stem cells (hESC)-derived cardiomyocytes. However, the methods used for measuring the Raman spectra led to acquisition times of minutes per cell, which is prohibitive for rapid cell sorting applications. In this study we evaluated two measurement strategies that could reduce the measurement time by a factor of more than 100. We show that sampling individual cells with a laser beam focused to a line could eliminate the need of cell raster scanning and achieve high prediction accuracies (>95% specificity and >96% sensitivity) with acquisition times ~5 seconds per cell. However, the use of commercially-available higher power lasers could potentially lead to sorting speeds of ~10 cells per s. This would start to progress RMS to the field of cell sorting for applications such as enrichment and purification of hESC-derived cardiomyocytes.

  4. Connecting Mitochondria, Metabolism, and Stem Cell Fate

    PubMed Central

    Wanet, Anaïs; Arnould, Thierry; Najimi, Mustapha

    2015-01-01

    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. PMID:26134242

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

    PubMed

    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.

  6. Skeletal stem cells

    PubMed Central

    Bianco, Paolo; Robey, Pamela G.

    2015-01-01

    Skeletal stem cells (SSCs) reside in the postnatal bone marrow and give rise to cartilage, bone, hematopoiesis-supportive stroma and marrow adipocytes in defined in vivo assays. These lineages emerge in a specific sequence during embryonic development and post natal growth, and together comprise a continuous anatomical system, the bone-bone marrow organ. SSCs conjoin skeletal and hematopoietic physiology, and are a tool for understanding and ameliorating skeletal and hematopoietic disorders. Here and in the accompanying poster, we concisely discuss the biology of SSCs in the context of the development and postnatal physiology of skeletal lineages, to which their use in medicine must remain anchored. PMID:25758217

  7. Neural Stem Cells and Ischemic Brain

    PubMed Central

    Zhang, Zhenggang; Chopp, Michael

    2016-01-01

    Stroke activates neural stem cells in the ventricular-subventricular zone (V/SVZ) of the lateral ventricle, which increases neuroblasts and oligodendrocyte progenitor cells (OPCs). Within the ischemic brain, neural stem cells, neuroblasts and OPCs appear to actively communicate with cerebral endothelial cells and other brain parenchymal cells to mediate ischemic brain repair; however, stroke-induced neurogenesis unlikely plays any significant roles in neuronal replacement. In this mini-review, we will discuss recent findings how intercellular communications between stroke-induced neurogenesis and oligodendrogenesis and brain parenchymal cells could potentially facilitate brain repair processes. PMID:27488979

  8. Dax1 binds to Oct3/4 and inhibits its transcriptional activity in embryonic stem cells.

    PubMed

    Sun, Chuanhai; Nakatake, Yuhki; Akagi, Tadayuki; Ura, Hiroki; Matsuda, Takahiko; Nishiyama, Akira; Koide, Hiroshi; Ko, Minoru S H; Niwa, Hitoshi; Yokota, Takashi

    2009-08-01

    Embryonic stem (ES) cells are pluripotent cells derived from the inner cell mass of blastocysts. Transcription factor Oct3/4 is an indispensable factor in the self-renewal of ES cells. In this study, we searched for a protein that would interact with Oct3/4 in ES cells and identified an orphan nuclear hormone receptor, Dax1. The association of Dax1 with Oct3/4 was mediated through the POU-specific domain of Oct3/4. Ectopic expression of Dax1 inhibited Oct3/4-mediated activation of an artificial Oct3/4-responsive promoter. Expression of Dax1 in ES cells also reduced the activities of Nanog and Rex1 promoters, while knockdown of Dax1 increased these activities. Pulldown and gel shift assays revealed that the interaction of Dax1 with Oct3/4 abolished the DNA binding activity of Oct3/4. Chromatin immunoprecipitation assay results showed that Dax1 inhibited Oct3/4 binding to the promoter/enhancer regions of Oct3/4 and Nanog. Furthermore, overexpression of Dax1 resulted in ES cell differentiation. Taken together, these data suggest that Dax1, a novel molecule interacting with Oct3/4, functions as a negative regulator of Oct3/4 in ES cells. PMID:19528230

  9. Mechanotransduction: Tuning Stem Cells Fate

    PubMed Central

    D'Angelo, Francesco; Tiribuzi, Roberto; Armentano, Ilaria; Kenny, Josè Maria; Martino, Sabata; Orlacchio, Aldo

    2011-01-01

    It is a general concern that the success of regenerative medicine-based applications is based on the ability to recapitulate the molecular events that allow stem cells to repair the damaged tissue/organ. To this end biomaterials are designed to display properties that, in a precise and physiological-like fashion, could drive stem cell fate both in vitro and in vivo. The rationale is that stem cells are highly sensitive to forces and that they may convert mechanical stimuli into a chemical response. In this review, we describe novelties on stem cells and biomaterials interactions with more focus on the implication of the mechanical stimulation named mechanotransduction. PMID:24956164

  10. DOT1L Activity Promotes Proliferation and Protects Cortical Neural Stem Cells from Activation of ATF4-DDIT3-Mediated ER Stress In Vitro.

    PubMed

    Roidl, Deborah; Hellbach, Nicole; Bovio, Patrick P; Villarreal, Alejandro; Heidrich, Stefanie; Nestel, Sigrun; Grüning, Björn A; Boenisch, Ulrike; Vogel, Tanja

    2016-01-01

    Growing evidence suggests that the lysine methyltransferase DOT1L/KMT4 has important roles in proliferation, survival, and differentiation of stem cells in development and in disease. We investigated the function of DOT1L in neural stem cells (NSCs) of the cerebral cortex. The pharmacological inhibition and shRNA-mediated knockdown of DOT1L impaired proliferation and survival of NSCs. DOT1L inhibition specifically induced genes that are activated during the unfolded protein response (UPR) in the endoplasmic reticulum (ER). Chromatin-immunoprecipitation analyses revealed that two genes encoding for central molecules involved in the ER stress response, Atf4 and Ddit3 (Chop), are marked with H3K79 methylation. Interference with DOT1L activity resulted in transcriptional activation of both genes accompanied by decreased levels of H3K79 dimethylation. Although downstream effectors of the UPR, such as Ppp1r15a/Gadd34, Atf3, and Tnfrsf10b/Dr5 were also transcriptionally activated, this most likely occurred in response to increased ATF4 expression rather than as a direct consequence of altered H3K79 methylation. While stem cells are particularly vulnerable to stress, the UPR and ER stress have not been extensively studied in these cells yet. Since activation of the ER stress program is also implicated in directing stem cells into differentiation or to maintain a proliferative status, the UPR must be tightly regulated. Our and published data suggest that histone modifications, including H3K4me3, H3K14ac, and H3K79me2, are implicated in the control of transcriptional activation of ER stress genes. In this context, the loss of H3K79me2 at the Atf4- and Ddit3-promoters appears to mark a point-of-no-return that activates the death program in NSCs.

  11. Current understanding concerning intestinal stem cells

    PubMed Central

    Cui, Shuang; Chang, Peng-Yu

    2016-01-01

    In mammals, the intestinal epithelium is a tissue that contains two distinct pools of stem cells: active intestinal stem cells and reserve intestinal stem cells. The former are located in the crypt basement membrane and are responsible for maintaining epithelial homeostasis under intact conditions, whereas the latter exhibit the capacity to facilitate epithelial regeneration after injury. These two pools of cells can convert into each other, maintaining their quantitative balance. In terms of the active intestinal stem cells, their development into functional epithelium is precisely controlled by the following signaling pathways: Wnt/β-catenin, Ras/Raf/Mek/Erk/MAPK, Notch and BMP/Smad. However, mutations in some of the key regulator genes associated with these signaling pathways, such as APC, Kras and Smad4, are also highly associated with gut malformations. At this point, clarifying the biological characteristics of intestinal stem cells will increase the feasibility of preventing or treating some intestinal diseases, such as colorectal cancer. Moreover, as preclinical data demonstrate the therapeutic effects of colon stem cells on murine models of experimental colitis, the prospects of stem cell-based regenerative treatments for ulcerous lesions in the gastrointestinal tract will be improved all the same.

  12. Current understanding concerning intestinal stem cells

    PubMed Central

    Cui, Shuang; Chang, Peng-Yu

    2016-01-01

    In mammals, the intestinal epithelium is a tissue that contains two distinct pools of stem cells: active intestinal stem cells and reserve intestinal stem cells. The former are located in the crypt basement membrane and are responsible for maintaining epithelial homeostasis under intact conditions, whereas the latter exhibit the capacity to facilitate epithelial regeneration after injury. These two pools of cells can convert into each other, maintaining their quantitative balance. In terms of the active intestinal stem cells, their development into functional epithelium is precisely controlled by the following signaling pathways: Wnt/β-catenin, Ras/Raf/Mek/Erk/MAPK, Notch and BMP/Smad. However, mutations in some of the key regulator genes associated with these signaling pathways, such as APC, Kras and Smad4, are also highly associated with gut malformations. At this point, clarifying the biological characteristics of intestinal stem cells will increase the feasibility of preventing or treating some intestinal diseases, such as colorectal cancer. Moreover, as preclinical data demonstrate the therapeutic effects of colon stem cells on murine models of experimental colitis, the prospects of stem cell-based regenerative treatments for ulcerous lesions in the gastrointestinal tract will be improved all the same. PMID:27610020

  13. Current understanding concerning intestinal stem cells.

    PubMed

    Cui, Shuang; Chang, Peng-Yu

    2016-08-21

    In mammals, the intestinal epithelium is a tissue that contains two distinct pools of stem cells: active intestinal stem cells and reserve intestinal stem cells. The former are located in the crypt basement membrane and are responsible for maintaining epithelial homeostasis under intact conditions, whereas the latter exhibit the capacity to facilitate epithelial regeneration after injury. These two pools of cells can convert into each other, maintaining their quantitative balance. In terms of the active intestinal stem cells, their development into functional epithelium is precisely controlled by the following signaling pathways: Wnt/β-catenin, Ras/Raf/Mek/Erk/MAPK, Notch and BMP/Smad. However, mutations in some of the key regulator genes associated with these signaling pathways, such as APC, Kras and Smad4, are also highly associated with gut malformations. At this point, clarifying the biological characteristics of intestinal stem cells will increase the feasibility of preventing or treating some intestinal diseases, such as colorectal cancer. Moreover, as preclinical data demonstrate the therapeutic effects of colon stem cells on murine models of experimental colitis, the prospects of stem cell-based regenerative treatments for ulcerous lesions in the gastrointestinal tract will be improved all the same. PMID:27610020

  14. Inhibition of HSP90 Promotes Neural Stem Cell Survival from Oxidative Stress through Attenuating NF-κB/p65 Activation

    PubMed Central

    Jiang, Wenkai; Zhou, Lin

    2016-01-01

    Stem cell survival after transplantation determines the efficiency of stem cell treatment, which develops as a novel potential therapy for several central nervous system (CNS) diseases in recent decades. The engrafted stem cells face the damage of oxidative stress, inflammation, and immune response at the lesion point in host. Among the damaging pathologies, oxidative stress directs stem cells to apoptosis and even death through several signalling pathways and DNA damage. However, the in-detail mechanism of stem cell survival from oxidative stress has not been revealed clearly. Here, in this study, we used hydrogen peroxide (H2O2) to induce the oxidative damage on neural stem cells (NSCs). The damage was in consequence demonstrated involving the activation of heat shock protein 90 (HSP90) and NF-κB/p65 signalling pathways. Further application of the pharmacological inhibitors, respectively, targeting at each signalling indicated an upper-stream role of HSP90 upon NF-κB/p65 on NSCs survival. Preinhibition of HSP90 with the specific inhibitor displayed a significant protection on NSCs against oxidative stress. In conclusion, inhibition of HSP90 would attenuate NF-κB/p65 activation by oxidative induction and promote NSCs survival from oxidative damage. The HSP90/NF-κB mechanism provides a new evidence on rescuing NSCs from oxidative stress and also promotes the stem cell application on CNS pathologies.

  15. Stem Cells, Redox Signaling, and Stem Cell Aging

    PubMed Central

    Liang, Raymond

    2014-01-01

    Abstract Significance: Functional stem cell decline has been postulated to result in loss of maintenance of tissue homeostasis leading to organismal decline and diseases of aging. Recent Advances: Recent findings implicate redox metabolism in the control of stem cell pool and stem cell aging. Although reactive oxygen species (ROS) are better known for their damaging properties to DNA, proteins and lipids, recent findings suggest that ROS may also be an integral physiological mediator of cellular signaling in primary cells. Critical Issues: Here we review recent published work on major signaling pathways and transcription factors that are regulated by ROS and mediate ROS regulation of stem cell fate. We will specifically focus on how alterations in this regulation may be implicated in disease and particularly in diseases of stem cell aging. In general, based on the work described here we propose a model in which ROS function as stem cell rheostat. Future Directions: Future work in elucidating how ROS control stem cell cycling, apoptotic machinery, and lineage determination should shed light on mechanisms whereby ROS may control stem cell aging. Antioxid. Redox Signal. 20, 1902–1916. PMID:24383555

  16. Pro-Oxidant Activity of Amine-Pyridine-Based Iron Complexes Efficiently Kills Cancer and Cancer Stem-Like Cells

    PubMed Central

    González-Bártulos, Marta; Aceves-Luquero, Clara; Qualai, Jamal; Cussó, Olaf; Martínez, Mª Angeles; Fernández de Mattos, Silvia; Menéndez, Javier A.; Villalonga, Priam; Costas, Miquel; Ribas, Xavi; Massaguer, Anna

    2015-01-01

    Differential redox homeostasis in normal and malignant cells suggests that pro-oxidant-induced upregulation of cellular reactive oxygen species (ROS) should selectively target cancer cells without compromising the viability of untransformed cells. Consequently, a pro-oxidant deviation well-tolerated by nonmalignant cells might rapidly reach a cell-death threshold in malignant cells already at a high setpoint of constitutive oxidative stress. To test this hypothesis, we took advantage of a selected number of amine-pyridine-based Fe(II) complexes that operate as efficient and robust oxidation catalysts of organic substrates upon reaction with peroxides. Five of these Fe(II)-complexes and the corresponding aminopyridine ligands were selected to evaluate their anticancer properties. We found that the iron complexes failed to display any relevant activity, while the corresponding ligands exhibited significant antiproliferative activity. Among the ligands, none of which were hemolytic, compounds 1, 2 and 5 were cytotoxic in the low micromolar range against a panel of molecularly diverse human cancer cell lines. Importantly, the cytotoxic activity profile of some compounds remained unaltered in epithelial-to-mesenchymal (EMT)-induced stable populations of cancer stem-like cells, which acquired resistance to the well-known ROS inducer doxorubicin. Compounds 1, 2 and 5 inhibited the clonogenicity of cancer cells and induced apoptotic cell death accompanied by caspase 3/7 activation. Flow cytometry analyses indicated that ligands were strong inducers of oxidative stress, leading to a 7-fold increase in intracellular ROS levels. ROS induction was associated with their ability to bind intracellular iron and generate active coordination complexes inside of cells. In contrast, extracellular complexation of iron inhibited the activity of the ligands. Iron complexes showed a high proficiency to cleave DNA through oxidative-dependent mechanisms, suggesting a likely mechanism of

  17. When stem cells grow old: phenotypes and mechanisms of stem cell aging.

    PubMed

    Schultz, Michael B; Sinclair, David A

    2016-01-01

    All multicellular organisms undergo a decline in tissue and organ function as they age. An attractive theory is that a loss in stem cell number and/or activity over time causes this decline. In accordance with this theory, aging phenotypes have been described for stem cells of multiple tissues, including those of the hematopoietic system, intestine, muscle, brain, skin and germline. Here, we discuss recent advances in our understanding of why adult stem cells age and how this aging impacts diseases and lifespan. With this increased understanding, it is feasible to design and test interventions that delay stem cell aging and improve both health and lifespan.

  18. Separation of SSEA-4 and TRA-1-60 labelled undifferentiated human embryonic stem cells from a heterogeneous cell population using magnetic-activated cell sorting (MACS) and fluorescence-activated cell sorting (FACS).

    PubMed

    Fong, Chui Yee; Peh, Gary S L; Gauthaman, Kalamegam; Bongso, Ariff

    2009-03-01

    A major concern in human embryonic stem cell (hESC)-derived cell replacement therapy is the risk of tumorigenesis from undifferentiated hESCs residing in the population of hESC-derived cells. Separation of these undifferentiated hESCs from the differentiated derivatives using cell sorting methods may be a plausible approach in overcoming this problem. We therefore explored magnetic activated cell sorting (MACS) and fluorescence activated cell sorting (FACS) to separate labelled undifferentiated hESCs from a heterogeneous population of hESCs and hepatocellular carcinoma cells (HepG2) deliberately mixed respectively at different ratios (10:90, 20:80, 30:70, 40:60 and 50:50) to mimic a standard in vitro differentiation protocol, instead of using a hESC-differentiated cell population, so that we could be sure of the actual number of cells separated. HES-3 and HES-4 cells were labelled in separate experiments for the stem cell markers SSEA-4 and TRA-1-60 using primary antibodies. Anti-PE magnetic microbeads that recognize the PE-conjugated SSEA-4 labelled hESCs was added to the heterogeneous cell mixture and passed through the MACS column. The cells that passed through the column ('flow-through' fraction) and those retained ('labelled' fraction') were subsequently analysed using FACS. The maximum efficacy of hESCs retention using MACS was 81.0 +/- 2.9% (HES-3) and 83.6 +/- 4.2% (HES-4). Using FACS, all the undifferentiated hESCs labelled with the two cell-surface markers could be removed by selective gating. Both hESCs and HepG2 cells in the 'flow-through' fraction following MACS separation were viable in culture whereas by FACS separation only the HepG2 cells were viable. FACS efficiently helps to eliminate the undifferentiated hESCs based on their cell-surface antigens expressed.

  19. Glucose uptake-stimulatory activity of Tinospora cordifolia stem extracts in Ehrlich ascites tumor cell model system.

    PubMed

    Joladarashi, Darukeshwara; Chilkunda, Nandini D; Salimath, Paramahans Veerayya

    2014-01-01

    Diabetes mellitus is a multifunctional disorder with several causes and multiple consequences. Nutraceuticals play a vital role in ameliorating diabetic condition. The stems of the plant, Tinospora cordifolia (T. cordifolia) are often used in Ayurvedic medicine for the management of diabetes. Earlier studies have shown that T. cordifolia to be a potent antidiabetic plant material by virtue of being rich in nutraceuticals. In the present study we were interested to know if, T. cordifolia stem extracts are able to promote glucose uptake through glucose transporters, 1 (GLUT1) and 3 (GLUT3), which are responsible for basal glucose uptake. Hence, Ehrlich ascites tumor (EAT) cells were chosen as a model which harbours both GLUT1 and GLUT3 and glucose uptake was measured using a fluorescent analog 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2-deoxy-D-glucose (2-NBDG). Serially, solvent extracted T. cordifolia stems, especially water, ethanol and methanol extracts showed glucose uptake activity. Uptake was stimulated in a dose dependent manner at dosages of 1-100 μg. Glucose-stimulating activity does not seem to be solely due to polyphenol content since methanol extract, with high amount of polyphenol content (9.5 ± 0.1 g kg(-1)), did not stimulate higher glucose uptake activity when compared to water extract. PMID:24426067

  20. Stressed stem cells: Temperature response in aged mesenchymal stem cells.

    PubMed

    Stolzing, Alexandra; Sethe, Sebastian; Scutt, Andrew M

    2006-08-01

    Mesenchymal stem cells (MSCs) derived from young (6 week) and aged (56 week) Wistar rats were cultured at standard (37 degrees C) and reduced (32 degrees C) temperature and compared for age markers and stress levels. (ROS, NO, TBARS, carbonyls, lipofuscin, SOD, GPx, apoptosis, proteasome activity) and heat shock proteins (HSP27, -60, -70, -90). Aged MSCs display many of the stress markers associated with aging in other cell types, but results vary across marker categories and are temperature dependant. In young MSCs, culturing at reduced temperature had a generally beneficial effect: the anti-apoptotic heat shock proteins HSP 27, HSP70, and HSP90 were up-regulated; pro-apoptotic HSP60 was downregulated; SOD, GPx increased; and levels in ROS, NO, TBARS, carbonyl, and lipofuscin were diminished. Apoptosis was reduced, but also proteasome activity. In contrast, in aged MSCs, culturing at reduced temperature generally produced no 'beneficial' changes in these parameters, and can even have detrimental effects. Implications for tissue engineering and for stem cell gerontology are discussed. The results suggest that a 'hormesis' theory of stress response can be extended to MSCs, but that cooling cultivation temperature stress produces positive effects in young cells only.

  1. The Rac GTPase effector p21-activated kinase is essential for hematopoietic stem/progenitor cell migration and engraftment.

    PubMed

    Dorrance, Adrienne M; De Vita, Serena; Radu, Maria; Reddy, Pavankumar N G; McGuinness, Meaghan K; Harris, Chad E; Mathieu, Ronald; Lane, Steven W; Kosoff, Rachelle; Milsom, Michael D; Chernoff, Jonathan; Williams, David A

    2013-03-28

    The p21-activated kinases (Paks) are serine/threonine kinases that are major effectors of the Rho guanosine 5'\\x{2011}triphosphatase, Rac, and Cdc42. Rac and Cdc42 are known regulators of hematopoietic stem and progenitor cell (HSPC) function, however, a direct role for Paks in HSPCs has yet to be elucidated. Lin(-)Sca1(+)c-kit(+) (LSK) cells from wild-type mice were transduced with retrovirus expressing Pak inhibitory domain (PID), a well-characterized inhibitor of Pak activation. Defects in marrow homing and in vitro cell migration, assembly of the actin cytoskeleton, proliferation, and survival were associated with engraftment failure of PID-LSK. The PID-LSK demonstrated decreased phosphorylation of extracellular signal-regulated kinase (ERK), whereas constitutive activation of ERK in these cells led to rescue of hematopoietic progenitor cell proliferation in vitro and partial rescue of Pak-deficient HSPC homing and engraftment in vivo. Using conditional knock-out mice, we demonstrate that among group A Paks, Pak2(-/-) HSPC show reduced homing to the bone marrow and altered cell shape similar to PID-LSK cells in vitro and are completely defective in HSPC engraftment. These data demonstrate that Pak proteins are key components of multiple engraftment-associated HSPC functions and play a direct role in activation of ERK in HSPCs, and that Pak2 is specifically essential for HSPC engraftment.

  2. [Stem cells and cardiac regeneration].

    PubMed

    Perez Millan, Maria Ines; Lorenti, Alicia

    2006-01-01

    Stem cells are defined by virtue of their functional attributes: absence of tissue specific differentitated markers, capable of proliferation, able to self-maintain the population, able to produce a large number of differentiated, functional progeny, able to regenerate the tissue after injury. Cell therapy is an alternative for the treatment of several diseases, like cardiac diseases (cell cardiomyoplasty). A variety of stem cells could be used for cardiac repair: from cardiac and extracardiac sources. Each cell type has its own profile of advantages, limitations, and practicability issues in specific clinical settings. Differentiation of bone marrow stem cells to cardiomyocyte-like cells have been observed under different culture conditions. The presence of resident cardiac stem cell population capable of differentiation into cardiomyocyte or vascular lineage suggests that these cells could be used for cardiac tissue repair, and represent a great promise for clinical application. Stem cells mobilization by cytokines may also offer a strategy for cardiac regeneration. The use of stem cells (embryonic and adult) may hold the key to replacing cells lost in many devastating diseases. This potential benefit is a major focus for stem cell research.

  3. Multicolor Time-lapse Imaging of Transgenic Zebrafish: Visualizing Retinal Stem Cells Activated by Targeted Neuronal Cell Ablation

    PubMed Central

    Mumm, Jeff S.

    2010-01-01

    High-resolution time-lapse imaging of living zebrafish larvae can be utilized to visualize how biological processes unfold (for review see 1). Compound transgenic fish which express different fluorescent reporters in neighboring cell types provide a means of following cellular interactions 2 and/or tissue-level responses to experimental manipulations over time. In this video, we demonstrate methods that can be used for imaging multiple transgenically labeled cell types serially in individual fish over time courses that can span from minutes to several days. The techniques described are applicable to any study seeking to correlate the "behavior" of neighboring cells types over time, including: 1) serial 'catch and release' methods for imaging a large number of fish over successive days, 2) simplified approaches for separating fluorophores with overlapping excitation/emission profiles (e.g., GFP and YFP), 3) use of hypopigmented mutant lines to extend the time window available for high-resolution imaging into late larval stages of development, 4) use of membrane targeted fluorescent reporters to reveal fine morphological detail of individual cells as well as cellular details in larger populations of cells, and 5) a previously described method for chemically-induced ablation of transgenically targeted cell types; i.e., nitroreductase (NTR) mediated conversion of prodrug substrates, such as metronidazole (MTZ), to cytotoxic derivatives 3,5. As an example of these approaches, we will visualize the ablation and regeneration of a subtype of retinal bipolar neuron within individual fish over several days. Simultaneously we will monitor several other retinal cell types, including neighboring non-targeted bipolar cells and potential degeneration-stimulated retinal stem cells (i.e., Mϋller glia). This strategy is being applied in our lab to characterize cell- and tissue-level (e.g., stem cell niche) responses to the selective loss and regeneration of targeted neuronal cell

  4. Hematopoietic stem and progenitor cell activation during chronic dermatitis provoked by constitutively active aryl-hydrocarbon receptor driven by Keratin 14 promoter.

    PubMed

    Murakami, Shohei; Yamamoto, Masayuki; Motohashi, Hozumi

    2014-03-01

    Polycyclic aromatic hydrocarbons (PAHs) activate aryl-hydrocarbon receptor (AhR). Because PAHs are known as a risk factor for allergic diseases, PAH-induced AhR activation is expected to be involved in the development of the pathology. We previously generated transgenic mice expressing a constitutively active AhR (AhR-CA) under the control of Keratin 14 (K14) promoter (AhR-CA mouse). The mice develop chronic dermatitis with immune imbalance toward Th2 predominance, indicating that the AhR activation driven by K14 promoter provokes allergic response. Because hematopoietic cells actively participate in the development of allergic inflammation, it is important to understand the hematopoietic status under allergic conditions. To clarify how the K14 promoter-driven AhR activation influences hematopoiesis, we analyzed bone marrow and spleen of AhR-CA mice. We verified that AhR-CA was expressed in keratinocytes and thymic epithelial cells but not in hematopoietic cells. The AhR-CA mice with full-blown dermatitis exhibited leukocytosis and skewed differentiation of hematopoietic progenitor cells toward granulocyte-monocyte lineages. They also showed a significant expansion of short-term hematopoietic stem cells and multipotent progenitors and a subtle reduction in long-term hematopoietic stem cells (LT-HSCs). Their spleens were enlarged and abundantly accumulated hematopoietic stem and progenitor cells. AhR-CA mice at the early stage of dermatitis did not show leukocytosis or splenomegaly but exhibited the granulocyte-monocyte skewing and the reduction in LT-HSCs. Thus, AhR activation driven by K14 promoter already alters the hematopoietic differentiation and reduces LT-HSCs at the initial stage of dermatitis development. These results suggest that nonhematopoietic exposure to PAHs triggers allergic response and concomitantly affects hematopoiesis.

  5. The Antiaging Properties of Andrographis paniculata by Activation Epidermal Cell Stemness.

    PubMed

    You, Jiyoung; Roh, Kyung-Baeg; Li, Zidan; Liu, Guangrong; Tang, Jian; Shin, Seoungwoo; Park, Deokhoon; Jung, Eunsun

    2015-01-01

    Andrographis paniculata (A. paniculata, Chuanxinlian), a medicinal herb with an extremely bitter taste that is native to China and other parts of Southeast Asia, possesses immense therapeutic value; however, its therapeutic properties have rarely been applied in the field of skin care. In this study, we investigated the effect of an A. paniculata extract (APE) on human epidermal stem cells (EpSCs), and confirmed its anti-aging effect through in vitro, ex vivo, and in vivo study. An MTT assay was used to determine cell proliferation. A flow cytometric analysis, with propidium iodide, was used to evaluate the cell cycle. The expression of integrin β1 (CD29), the stem cell marker, was detected with antibodies, using flow cytometry in vitro, and immunohistochemical assays in ex vivo. Type 1 collagen and VEGF (vascular endothelial growth factor) were measured using an enzyme-linked immunosorbent assay (ELISA). During the clinical study, skin hydration, elasticity, wrinkling, sagging, and dermal density were evaluated before treatment and at four and eight weeks after the treatment with the test product (containing the APE) on the face. The proliferation of the EpSCs, treated with the APE, increased significantly. In the cell cycle analysis, the APE increased the G2/M and S stages in a dose-dependent manner. The expression of integrin β1, which is related to epidermal progenitor cell expansion, was up-regulated in the APE-treated EpSCs and skin explants. In addition, the production of VEGF in the EpSCs increased significantly in response to the APE treatment. Consistent with these results, the VEGF and APE-treated EpSCs conditioned medium enhanced the Type 1 collagen production in normal human fibroblasts (NHFs). In the clinical study, the APE improved skin hydration, dermal density, wrinkling, and sagging significantly. Our findings revealed that the APE promotes a proliferation of EpSCs, through the up-regulation of the integrin β1 and VEGF expression. The VEGF

  6. Zfra activates memory Hyal-2+ CD3- CD19- spleen cells to block cancer growth, stemness, and metastasis in vivo.

    PubMed

    Lee, Ming-Hui; Su, Wan-Pei; Wang, Wan-Jen; Lin, Sing-Ru; Lu, Chen-Yu; Chen, Yu-An; Chang, Jean-Yun; Huang, Shenq-Shyang; Chou, Pei-Yi; Ye, Siou-Ru; Chen, Szu-Jung; He, Huan; Liu, Ting-Hsiu; Chou, Ying-Tsen; Hsu, Li-Jin; Lai, Feng-Jie; Chen, Shean-Jen; Lee, Hoong-Chien; Kakhniashvili, David; Goodman, Steven R; Chang, Nan-Shan

    2015-02-28

    Zfra is a 31-amino-acid zinc finger-like protein, which participates in the tumor necrosis factor signaling. Here, we determined that when nude mice and BALB/c mice were pre-injected with nanogram levels of a synthetic Zfra1-31 or truncated Zfra4-10 peptide via tail veins, these mice became resistant to the growth, metastasis and stemness of melanoma cells, and many malignant cancer cells. The synthetic peptides underwent self-polymerization in phosphate-buffered saline. Alteration of the Ser8 phosphorylation site to Gly8 abolished Zfra aggregation and its-mediated cancer suppression in vivo. Injected Zfra peptide autofluoresced due to polymerization and was trapped mainly in the spleen. Transfer of Zfra-stimulated spleen cells to naïve mice conferred resistance to cancer growth. Zfra-binding cells, designated Hyal-2+ CD3- CD19- Z cells, are approximately 25-30% in the normal spleen, but are significantly downregulated (near 0-3%) in tumor-growing mice. Zfra prevented the loss of Z cells caused by tumors. In vitro stimulation or education of naïve spleen cells with Zfra allowed generation of activated Z cells to confer a memory anticancer response in naïve or cancer-growing mice. In particular, Z cells are abundant in nude and NOD-SCID mice, and can be readily activated by Zfra to mount against cancer growth.

  7. Involvement of Plant Stem Cells or Stem Cell-Like Cells in Dedifferentiation.

    PubMed

    Jiang, Fangwei; Feng, Zhenhua; Liu, Hailiang; Zhu, Jian

    2015-01-01

    Dedifferentiation is the transformation of cells from a given differentiated state to a less differentiated or stem cell-like state. Stem cell-related genes play important roles in dedifferentiation, which exhibits similar histone modification and DNA methylation features to stem cell maintenance. Hence, stem cell-related factors possibly synergistically function to provide a specific niche beneficial to dedifferentiation. During callus formation in Arabidopsis petioles, cells adjacent to procambium cells (stem cell-like cells) are dedifferentiated and survive more easily than other cell types. This finding indicates that stem cells or stem cell-like cells may influence the dedifferentiating niche. In this paper, we provide a brief overview of stem cell maintenance and dedifferentiation regulation. We also summarize current knowledge of genetic and epigenetic mechanisms underlying the balance between differentiation and dedifferentiation. Furthermore, we discuss the correlation of stem cells or stem cell-like cells with dedifferentiation. PMID:26635851

  8. Effect of Local Heating and Cooling on Cambial Activity and Cell Differentiation in the Stem of Norway Spruce (Picea abies)

    PubMed Central

    GRIČAR, JOŽICA; ZUPANČIČ, MARTIN; ČUFAR, KATARINA; KOCH, GERALD; SCHMITT, UWE; OVEN, PRIMOŽ

    2006-01-01

    • Background and Aims The effect of heating and cooling on cambial activity and cell differentiation in part of the stem of Norway spruce (Picea abies) was investigated. • Methods A heating experiment (23–25 °C) was carried out in spring, before normal reactivation of the cambium, and cooling (9–11 °C) at the height of cambial activity in summer. The cambium, xylem and phloem were investigated by means of light- and transmission electron microscopy and UV-microspectrophotometry in tissues sampled from living trees. • Key Results Localized heating for 10 d initiated cambial divisions on the phloem side and after 20 d also on the xylem side. In a control tree, regular cambial activity started after 30 d. In the heat-treated sample, up to 15 earlywood cells undergoing differentiation were found to be present. The response of the cambium to stem cooling was less pronounced, and no anatomical differences were detected between the control and cool-treated samples after 10 or 20 d. After 30 d, latewood started to form in the sample exposed to cooling. In addition, almost no radially expanding tracheids were observed and the cambium consisted of only five layers of cells. Low temperatures reduced cambial activity, as indicated by the decreased proportion of latewood. On the phloem side, no alterations were observed among cool-treated and non-treated samples. • Conclusions Heating and cooling can influence cambial activity and cell differentiation in Norway spruce. However, at the ultrastructural and topochemical levels, no changes were observed in the pattern of secondary cell-wall formation and lignification or in lignin structure, respectively. PMID:16613904

  9. Photoactivation of ROS Production In Situ Transiently Activates Cell Proliferation in Mouse Skin and in the Hair Follicle Stem Cell Niche Promoting Hair Growth and Wound Healing.

    PubMed

    Carrasco, Elisa; Calvo, María I; Blázquez-Castro, Alfonso; Vecchio, Daniela; Zamarrón, Alicia; de Almeida, Irma Joyce Dias; Stockert, Juan C; Hamblin, Michael R; Juarranz, Ángeles; Espada, Jesús

    2015-11-01

    The role of reactive oxygen species (ROS) in the regulation of hair follicle (HF) cycle and skin homeostasis is poorly characterized. ROS have been traditionally linked to human disease and aging, but recent findings suggest that they can also have beneficial physiological functions in vivo in mammals. To test this hypothesis, we transiently switched on in situ ROS production in mouse skin. This process activated cell proliferation in the tissue and, interestingly, in the bulge region of the HF, a major reservoir of epidermal stem cells, promoting hair growth, as well as stimulating tissue repair after severe burn injury. We further show that these effects were associated with a transient Src kinase phosphorylation at Tyr416 and with a strong transcriptional activation of the prolactin family 2 subfamily c of growth factors. Our results point to potentially relevant modes of skin homeostasis regulation and demonstrate that a local and transient ROS production can regulate stem cell and tissue function in the whole organism.

  10. The new stem cell biology.

    PubMed Central

    Quesenberry, Peter J.; Colvin, Gerald A.; Lambert, Jean-Francois; Frimberger, Angela E.; Dooner, Mark S.; Mcauliffe, Christina I.; Miller, Caroline; Becker, Pamela; Badiavas, Evangelis; Falanga, Vincent J.; Elfenbein, Gerald; Lum, Lawrence G.

    2002-01-01

    Recent studies have indicated that bone marrow stem cells are capable of generating muscle, cardiac, hepatic, renal, and bone cells. Purified hematopoietic stem cells have generated cardiac and hepatic cells and reversed disease manifestations in these tissues. Hematopoietic stem cells also alter phenotype with cell cycle transit or circadian phase. During a cytokine stimulated cell cycle transit, reversible alterations of differentiation and engraftment occur. Primitive hematopoietic stem cells express a wide variety of adhesion and cytokine receptors and respond quickly with migration and podia extensions on exposure to cytokines. These data suggest an "Open Chromatin" model of stem cell regulation in which there is a fluctuating continuum in the stem cell/progenitor cell compartments, rather than a hierarchical relationship. These observations, along with progress in using low dose treatments and tolerization approaches, suggest many new therapeutic strategies involving stem cells and the creation of a new medical specialty; stemology. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:12053709

  11. Bioprinting for stem cell research

    PubMed Central

    Tasoglu, Savas; Demirci, Utkan

    2012-01-01

    Recently, there has been a growing interest to apply bioprinting techniques to stem cell research. Several bioprinting methods have been developed utilizing acoustics, piezoelectricity, and lasers to deposit living cells onto receiving substrates. Using these technologies, spatially defined gradients of immobilized proteins can be engineered to direct stem cell differentiation into multiple subpopulations of different lineages. Stem cells can also be patterned in a high-throughput manner onto flexible implementation patches for tissue regeneration or onto substrates with the goal of accessing encapsulated stem cell of interest for genomic analysis. Here, we review recent achievements with bioprinting technologies in stem cell research, and identify future challenges and potential applications including tissue engineering and regenerative medicine, wound healing, and genomics. PMID:23260439

  12. Stem cells for spine surgery.

    PubMed

    Schroeder, Joshua; Kueper, Janina; Leon, Kaplan; Liebergall, Meir

    2015-01-26

    In the past few years, stem cells have become the focus of research by regenerative medicine professionals and tissue engineers. Embryonic stem cells, although capable of differentiating into cell lineages of all three germ layers, are limited in their utilization due to ethical issues. In contrast, the autologous harvest and subsequent transplantation of adult stem cells from bone marrow, adipose tissue or blood have been experimentally utilized in the treatment of a wide variety of diseases ranging from myocardial infarction to Alzheimer's disease. The physiologic consequences of stem cell transplantation and its impact on functional recovery have been studied in countless animal models and select clinical trials. Unfortunately, the bench to bedside translation of this research has been slow. Nonetheless, stem cell therapy has received the attention of spinal surgeons due to its potential benefits in the treatment of neural damage, muscle trauma, disk degeneration and its potential contribution to bone fusion.

  13. Expansion and long-term culture of human spermatogonial stem cells via the activation of SMAD3 and AKT pathways

    PubMed Central

    Guo, Ying; Liu, Linhong; Sun, Min; Hai, Yanan; Li, Zheng

    2015-01-01

    Spermatogonial stem cells (SSCs) can differentiate into spermatids, reflecting that they could be used in reproductive medicine for treating male infertility. SSCs are able to become embryonic stem-like cells with the potentials of differentiating into numerous cell types of the three germ layers and they can transdifferentiate to mature and functional cells of other lineages, highlighting significant applications of human SSCs for treating human diseases. However, human SSCs are very rare and a long-term culture system of human SSCs has not yet established. This aim of study was to isolate, identify and culture human SSCs for a long period. We isolated GPR125-positive spermatogonia with high purity and viability from adult human testicular tissues utilizing the two-step enzymatic digestion and magnetic-activated cell sorting with antibody against GPR125. These freshly isolated cells expressed a number of markers for SSCs, including GPR125, PLZF, GFRA1, RET, THY1, UCHL1 and MAGEA4, but not the hallmarks for spermatocytes and spermatozoa, e.g. SYCP1, SYCP3, PRM1, and TNP1. The isolated human SSCs could be cultured for two months with a significant increase of cell number with the defined medium containing growth factors and hydrogel. Notably, the expression of numerous SSC markers was maintained during the cultivation of human SSCs. Furthermore, SMAD3 and AKT phosphorylation was enhanced during the culture of human SSCs. Collectively, these results suggest that human SSCs can be cultivated for a long period and expanded whilst retaining an undifferentiated status via the activation of SMAD3 and AKT pathways. This study could provide sufficient cells of SSCs for their basic research and clinic applications in reproductive and regenerative medicine. PMID:26088866

  14. Amelioration of radiation-induced hematopoietic syndrome by an antioxidant chlorophyllin through increased stem cell activity and modulation of hematopoiesis.

    PubMed

    Suryavanshi, Shweta; Sharma, Deepak; Checker, Rahul; Thoh, Maikho; Gota, Vikram; Sandur, Santosh K; Sainis, Krishna B

    2015-08-01

    Hematopoietic stem cells and progenitor cells (HSPC) are low in abundance and exhibit high radiosensitivity and their ability to divide dramatically decreases following exposure to ionizing radiation. Our earlier studies have shown antiapoptotic, immune-stimulatory, and antioxidant effects of chlorophyllin, a constituent of the over the counter drug derifil. Here we describe the beneficial effects of chlorophyllin against radiation-induced hematopoietic syndrome. Chlorophyllin administration significantly enhanced the abundance of HSPC in vivo. It induced a transient cell cycle arrest in lineage-negative cells in the bone marrow. However, the chlorophyllin-treated mice exposed to whole body irradiation (WBI) had a significantly higher proportion of actively dividing HSPC in the bone marrow as compared to only WBI-exposed mice. It significantly increased the number of colony forming units (CFUs) by bone marrow cells in vitro and spleen CFUs in irradiated mice in vivo. Pharmacokinetic study showed that chlorophyllin had a serum half-life of 141.8 min in mice. Chlorophyllin upregulated antiapoptotic genes and antioxidant machinery via activation of prosurvival transcription factors Nrf-2 and NF-κB and increased the survival and recovery of bone marrow cells in mice exposed to WBI. Chlorophyllin stimulated granulocyte production in bone marrow and increased the abundance of peripheral blood neutrophils by enhancing serum levels of granulocyte-colony stimulation factor (GCSF). Most importantly, prophylactic treatment of mice with chlorophyllin significantly abrogated radiation-induced mortality. Chlorophyllin mitigates radiation-induced hematopoietic syndrome by increasing the abundance of hematopoietic stem cells, enhancing granulopoiesis, and stimulating prosurvival pathways in bone marrow cells and lymphocytes.

  15. Stem cell applications in military medicine.

    PubMed

    Christopherson, Gregory T; Nesti, Leon J

    2011-10-19

    There are many similarities between health issues affecting military and civilian patient populations, with the exception of the relatively small but vital segment of active soldiers who experience high-energy blast injuries during combat. A rising incidence of major injuries from explosive devices in recent campaigns has further complicated treatment and recovery, highlighting the need for tissue regenerative options and intensifying interest in the possible role of stem cells for military medicine. In this review we outline the array of tissue-specific injuries typically seen in modern combat - as well as address a few complications unique to soldiers--and discuss the state of current stem cell research in addressing each area. Embryonic, induced-pluripotent and adult stem cell sources are defined, along with advantages and disadvantages unique to each cell type. More detailed stem cell sources are described in the context of each tissue of interest, including neural, cardiopulmonary, musculoskeletal and sensory tissues, with brief discussion of their potential role in regenerative medicine moving forward. Additional commentary is given to military stem cell applications aside from regenerative medicine, such as blood pharming, immunomodulation and drug screening, with an overview of stem cell banking and the unique opportunity provided by the military and civilian overlap of stem cell research.

  16. Stem cell applications in military medicine.

    PubMed

    Christopherson, Gregory T; Nesti, Leon J

    2011-01-01

    There are many similarities between health issues affecting military and civilian patient populations, with the exception of the relatively small but vital segment of active soldiers who experience high-energy blast injuries during combat. A rising incidence of major injuries from explosive devices in recent campaigns has further complicated treatment and recovery, highlighting the need for tissue regenerative options and intensifying interest in the possible role of stem cells for military medicine. In this review we outline the array of tissue-specific injuries typically seen in modern combat - as well as address a few complications unique to soldiers--and discuss the state of current stem cell research in addressing each area. Embryonic, induced-pluripotent and adult stem cell sources are defined, along with advantages and disadvantages unique to each cell type. More detailed stem cell sources are described in the context of each tissue of interest, including neural, cardiopulmonary, musculoskeletal and sensory tissues, with brief discussion of their potential role in regenerative medicine moving forward. Additional commentary is given to military stem cell applications aside from regenerative medicine, such as blood pharming, immunomodulation and drug screening, with an overview of stem cell banking and the unique opportunity provided by the military and civilian overlap of stem cell research. PMID:22011454

  17. Stem cell applications in military medicine

    PubMed Central

    2011-01-01

    There are many similarities between health issues affecting military and civilian patient populations, with the exception of the relatively small but vital segment of active soldiers who experience high-energy blast injuries during combat. A rising incidence of major injuries from explosive devices in recent campaigns has further complicated treatment and recovery, highlighting the need for tissue regenerative options and intensifying interest in the possible role of stem cells for military medicine. In this review we outline the array of tissue-specific injuries typically seen in modern combat - as well as address a few complications unique to soldiers - and discuss the state of current stem cell research in addressing each area. Embryonic, induced-pluripotent and adult stem cell sources are defined, along with advantages and disadvantages unique to each cell type. More detailed stem cell sources are described in the context of each tissue of interest, including neural, cardiopulmonary, musculoskeletal and sensory tissues, with brief discussion of their potential role in regenerative medicine moving forward. Additional commentary is given to military stem cell applications aside from regenerative medicine, such as blood pharming, immunomodulation and drug screening, with an overview of stem cell banking and the unique opportunity provided by the military and civilian overlap of stem cell research. PMID:22011454

  18. The advantages of hair follicle pluripotent stem cells over embryonic stem cells and induced pluripotent stem cells for regenerative medicine.

    PubMed

    Amoh, Yasuyuki; Katsuoka, Kensei; Hoffman, Robert M

    2010-12-01

    Multipotent adult stem cells have many potential therapeutic applications. Our recent findings suggest that hair follicles are a promising source of easily accessible multipotent stem cells. Stem cells in the hair follicle area express the neural stem cell marker nestin, suggesting that hair-follicle stem cells and neural stem cells have common features. Nestin-expressing hair follicle stem cells can form neurons and other cell types, and thus adult hair follicle stem cells could have important therapeutic applications, particularly for neurologic diseases. Transplanted hair follicle stem cells promote the functional recovery of injured peripheral nerve and spinal cord. Recent findings suggest that direct transplantation of hair-follicle stem cells without culture can promote nerve repair, which makes them potentially clinically practical. Human hair follicle stem cells as well as mouse hair follicle stem cells promote nerve repair and can be applied to test the hypothesis that human hair follicle stem cells can provide a readily available source of neurologically therapeutic stem cells. The use of hair follicle stem cells for nerve regeneration overcomes critical problems of embryonic stem cells or induced pluripotent stem cells in that the hair follicle stem cells are multipotent, readily accessible, non-oncogenic, and are not associated with ethical issues.

  19. Stem cells, colorectal cancer and cancer stem cell markers correlations.

    PubMed

    Cherciu, Irina; Bărbălan, A; Pirici, D; Mărgăritescu, C; Săftoiu, A

    2014-01-01

    : The idea of stem cells as being progenitors of cancer was initially controversial, but later supported by research in the field of leukemia and solid tumors. Afterwards, it was established that genetic abnormalities can affect the stem and progenitor cells, leading to uncontrolled replication and deregulated differentiation. These alterations will cause the changeover to cancerous stem cells (CSC) having two main characteristics: tumor initiation and maintenance. This review will focus on the colorectal cancer stem cell (CR-CSCs) theory which provides a better understanding of different tumor processes: initiation, aggressive growth, recurrence, treatment resistance and metastasis. A search in PubMed/Medline was performed using the following keywords: colorectal cancer stem cells (CR-CSCs), colorectal neoplasms stem cells, colorectal cancer stem cell (CR-CSCs) markers, etc. Electronic searches were supplemented by hand searching reference lists, abstracts and proceedings from meetings. Isolation of CR-CSCs can be achieved by targeting and selecting subpopulation of tumor cells based on expression of one or multiple cell surface markers associated with cancer self-renewal, markers as: CD133, CD166, CD44, CD24, beta1 integrin-CD29, Lgr5, EpCAM (ESA), ALDH-1, Msi-1, DCAMLK1 or EphB receptors. The identification and localization of CR-CSCs through different markers will hopefully lead to a better stratification of prognosis and treatment response, as well as the development of new effective strategies for cancer management.

  20. NFATc1 balances quiescence and proliferation of skin stem cells

    PubMed Central

    Horsley, Valerie; Aliprantis, Antonios O.; Polak, Lisa; Glimcher, Laurie H.; Fuchs, Elaine

    2008-01-01

    Quiescent adult stem cells reside in specialized niches where they become activated to proliferate and differentiate during tissue homeostasis and injury. How stem cell quiescence is governed is poorly understood. We report here that NFATc1 is preferentially expressed by hair follicle stem cells in their niche, where it's expression is activated by BMP signaling upstream and it acts downstream to transcriptionally repress CDK4 and maintain stem cell quiescence. As stem cells become activated during hair growth, NFATc1 is downregulated, relieving CDK4 repression and activating proliferation. When calcineurin/NFATc1 signaling is suppressed, pharmacologically or via complete or conditional NFATc1 gene ablation, stem cells are activated prematurely, resulting in precocious follicular growth. Our findings may explain why patients receiving cyclosporine A for immunosuppressive therapy display excessive hair growth, and unveil a functional role for calcium-NFATc1-CDK4 circuitry in governing stem cell quiescence. PMID:18243104

  1. Mesenchymal Stem Cells in Cardiology.

    PubMed

    White, Ian A; Sanina, Cristina; Balkan, Wayne; Hare, Joshua M

    2016-01-01

    Cardiovascular disease (CVD) accounts for more deaths globally than any other single disease. There are on average 1.5 million episodes of myocardial infarction (heart attack) each year in the United States alone with roughly one-third resulting in death. There is therefore a major need for developing new and effective strategies to promote cardiac repair. Intramyocardial transplantation of mesenchymal stem cells (MSCs) has emerged as a leading contender in the pursuit of clinical intervention and therapy. MSCs are potent mediators of cardiac repair and are therefore an attractive tool in the development of preclinical and clinical trials. MSCs are capable of secreting a large array of soluble factors, which have had demonstrated effects on pathogenic cardiac remolding, fibrosis, immune activation, and cardiac stem cell proliferation within the damaged heart. MSCs are also capable of differentiation into cardiomyocytes, endothelial cells, and vascular smooth muscle cells, although the relative contribution of trilineage differentiation and paracrine effectors on cardiac repair remains the subject of active investigation. PMID:27236666

  2. Assessment of immunosuppressive activity of human mesenchymal stem cells using murine antigen specific CD4 and CD8 T cells in vitro

    PubMed Central

    2013-01-01

    Introduction Mesenchymal stem cells (MSCs) have immunosuppressive activity. They do not induce allospecific T cell responses, making them promising tools for reducing the severity of graft versus host disease (GVHD) as well as treating various immune diseases. Currently, there is a need in the MSC field to develop a robust in vitro bioassay which can characterize the immunosuppressive function of MSCs. Methods Murine clonal CD4 and CD8 T cells were stimulated with cognate peptide antigen and antigen presenting cells (APCs) in the absence or presence of human MSCs, different aspects of T cell activation were monitored and analyzed using flow cytometery, real time RT-PCR and cytokine measurement. Results Human MSCs (hMSCs) can alter multiple aspects of murine T cell activation induced by stimulation with specific antigen, including: reduced proliferation, inhibited or stimulated cell surface marker expression (CD25, CD69, CD44 and CD62L), inhibited mRNA expression of transcription factors (T-bet and GATA-3) and decreased cytokine expression (interferon-gamma, interleukin-10). Disappearance of activation-induced cluster formation and decreased apoptosis of CD8 T cells were also observed. Moreover, the effects are specific to MSCs; incubating the T cells with non-MSC control cell lines had no effect on T cell proliferation and activation. Conclusions Clonal murine T cells can be used to measure, characterize, and quantify the in vitro immunosuppressive activity of human MSCs, representing a promising approach to improve bioassays for immunosuppression. PMID:24406271

  3. Comparison of the metabolic activation of environmental carcinogens in mouse embryonic stem cells and mouse embryonic fibroblasts

    PubMed Central

    Krais, Annette M.; Mühlbauer, Karl-Rudolf; Kucab, Jill E.; Chinbuah, Helena; Cornelius, Michael G.; Wei, Quan-Xiang; Hollstein, Monica; Phillips, David H.; Arlt, Volker M.; Schmeiser, Heinz H.

    2015-01-01

    We compared mouse embryonic stem (ES) cells and fibroblasts (MEFs) for their ability to metabolically activate the environmental carcinogens benzo[a]pyrene (BaP), 3-nitrobenzanthrone (3-NBA) and aristolochic acid I (AAI), measuring DNA adduct formation by 32P-postlabelling and expression of xenobiotic-metabolism genes by quantitative real-time PCR. At 2 μM, BaP induced Cyp1a1 expression in MEFs to a much greater extent than in ES cells and formed 45 times more adducts. Nqo1 mRNA expression was increased by 3-NBA in both cell types but induction was higher in MEFs, as was adduct formation. For AAI, DNA binding was over 450 times higher in MEFs than in ES cells, although Nqo1 and Cyp1a1 transcriptional levels did not explain this difference. We found higher global methylation of DNA in ES cells than in MEFs, which suggests higher chromatin density and lower accessibility of the DNA to DNA damaging agents in ES cells. However, AAI treatment did not alter DNA methylation. Thus mouse ES cells and MEFs have the metabolic competence to activate a number of environmental carcinogens, but MEFs have lower global DNA methylation and higher metabolic capacity than mouse ES cells. PMID:25230394

  4. FDA Warns About Stem Cell Claims

    MedlinePlus

    ... Home For Consumers Consumer Updates FDA Warns About Stem Cell Claims Share Tweet Linkedin Pin it More sharing ... blood-forming system. back to top Regulation of Stem Cells FDA regulates stem cells in the U.S. to ...

  5. Retinoic acid suppresses the canonical Wnt signaling pathway in embryonic stem cells and activates the noncanonical Wnt signaling pathway

    PubMed Central

    Osei-Sarfo, Kwame; Gudas, Lorraine J.

    2014-01-01

    Embryonic stem cells (ESCs) have both the ability to self-renew and to differentiate into various cell lineages. Retinoic acid (RA), a metabolite of Vitamin A, has a critical function in initiating lineage differentiation of ESCs through binding to the retinoic acid receptors (RARs). Additionally, the Wnt signaling pathway plays a role in pluripotency and differentiation, depending on the activation status of the canonical and noncanonical pathways. The activation of the canonical Wnt signaling pathway, which requires the nuclear accumulation of β-catenin and its interaction with Tcf1/Lef at Wnt response elements, is involved in ESC stemness maintenance. The noncanonical Wnt signaling pathway, through actions of Tcf3, can antagonize the canonical pathway. We show that RA activates the noncanonical Wnt signaling pathway, while concomitantly inhibiting the canonical pathway. RA increases the expression of ligands and receptors of the noncanonical Wnt pathway (Wnt 5a, 7a, Fzd2 and Fzd6), downstream signaling, and Tcf3 expression. RA reduces the phosphorylated β-catenin level by 4-fold, though total β-catenin levels don't change. We show that RA signaling increases the dissociation of Tcf1 and the association of Tcf3 at promoters of genes that regulate stemness (e.g. NR5A2,Lrh-1) or differentiation (eg. Cyr61, Zic5). Knockdown of Tcf3 increases Lrh-1 transcript levels in mESCs and prevents the RA-associated, ∼4-fold increase in Zic5, indicating that RA requires Tcf3 to effect changes in Zic5 levels. We demonstrate a novel role for RA in altering the activation of these two Wnt signaling pathways and show that Tcf3 mediates some actions of RA during differentiation. PMID:24648413

  6. Methods to monitor distribution and metabolic activity of mesenchymal stem cells following in vivo injection into nucleotomized porcine intervertebral discs.

    PubMed

    Omlor, G W; Bertram, H; Kleinschmidt, K; Fischer, J; Brohm, K; Guehring, T; Anton, M; Richter, Wiltrud

    2010-04-01

    Intervertebral disc (IVD) degeneration involves a series of biochemical and morphological changes leading to loss of spinal stability and flexibility. Cell therapy is promising to reconstitute IVDs with new cells, however, sustained metabolic activity seems crucial for an active contribution to regeneration. The aim of the present study was to establish methods for separate follow up of persistence and activity of autologous porcine mesenchymal stem cells (pMSC) after implantation into IVDs of Goettingen minipigs in vivo in order to conclude about the potential of such an intervention strategy. For quantitative follow up, the transfer matrix was supplemented with Al(2)O(3) particles and pMSC which were retrovirally labeled with firefly luciferase (pMSC-Luc). Six mature Goettingen minipigs underwent matrix based cell transfer after partial nucleotomy of lumbar IVDs (n = 24). Day 0 and day 3 segments were analyzed for retained volume of Al(2)O(3) particles by micro-computed-tomography (muCT) and for cell activity by luciferase enzyme assessment. Three days after injection a reduction of Al(2)O(3) particles (P = 0.028) to about 9% and of pMSC-Luc activity to about 7% of initial values (P = 0.003) was detected, which suggests loss of 90% of the implant material under in vivo conditions without evidence for reduced pMSC-Luc metabolic activity (P = 0.887). In conclusion, separate follow up of implant material and cell activity was possible and unravels problems with in vivo implant persistence after annular puncture rather than quick loss of cell activity. Therefore, IVD-regeneration-strategies should increasingly focus on annulus reconstruction in order to reduce implant loss due to annular failure.

  7. Progressive alopecia reveals decreasing stem cell activation probability during aging of mice with epidermal deletion of DNA methyltransferase 1.

    PubMed

    Li, Ji; Jiang, Ting-Xin; Hughes, Michael W; Wu, Ping; Yu, Juehua; Widelitz, Randall B; Fan, Guoping; Chuong, Cheng-Ming

    2012-12-01

    To examine the roles of epigenetic modulation on hair follicle regeneration, we generated mice with a K14-Cre-mediated loss of DNA methyltransferase 1 (DNMT1). The mutant shows an uneven epidermal thickness and alterations in hair follicle size. When formed, hair follicle architecture and differentiation appear normal. Hair subtypes exist but hair fibers are shorter and thinner. Hair numbers appear normal at birth but gradually decrease to <50% of control in 1-year-old mice. Sections of old mutant skin show follicles in prolonged telogen with hyperplastic sebaceous glands. Anagen follicles in mutants exhibit decreased proliferation and increased apoptosis in matrix transient-amplifying cells. Although K15-positive stem cells in the mutant bulge are comparable in number to the control, their ability to proliferate and become activated to form a hair germ is reduced. As mice age, residual DNMT activity declines further, and the probability of successful anagen reentry decreases, leading to progressive alopecia. Paradoxically, there is increased proliferation in the epidermis, which also shows aberrant differentiation. These results highlight the importance of DNA methylation in maintaining stem cell homeostasis during the development and regeneration of ectodermal organs.

  8. p38α Activates Purine Metabolism to Initiate Hematopoietic Stem/Progenitor Cell Cycling in Response to Stress.

    PubMed

    Karigane, Daiki; Kobayashi, Hiroshi; Morikawa, Takayuki; Ootomo, Yukako; Sakai, Mashito; Nagamatsu, Go; Kubota, Yoshiaki; Goda, Nobuhito; Matsumoto, Michihiro; Nishimura, Emi K; Soga, Tomoyoshi; Otsu, Kinya; Suematsu, Makoto; Okamoto, Shinichiro; Suda, Toshio; Takubo, Keiyo

    2016-08-01

    Hematopoietic stem cells (HSCs) maintain quiescence by activating specific metabolic pathways, including glycolysis. We do not yet have a clear understanding of how this metabolic activity changes during stress hematopoiesis, such as bone marrow transplantation. Here, we report a critical role for the p38MAPK family isoform p38α in initiating hematopoietic stem and progenitor cell (HSPC) proliferation during stress hematopoiesis in mice. We found that p38MAPK is immediately phosphorylated in HSPCs after a hematological stress, preceding increased HSPC cycling. Conditional deletion of p38α led to defective recovery from hematological stress and a delay in initiation of HSPC proliferation. Mechanistically, p38α signaling increases expression of inosine-5'-monophosphate dehydrogenase 2 in HSPCs, leading to altered levels of amino acids and purine-related metabolites and changes in cell-cycle progression in vitro and in vivo. Our studies have therefore uncovered a p38α-mediated pathway that alters HSPC metabolism to respond to stress and promote recovery. PMID:27345838

  9. Immunological characteristics of mesenchymal stem cells

    PubMed Central

    Machado, Cíntia de Vasconcellos; Telles, Paloma Dias da Silva; Nascimento, Ivana Lucia Oliveira

    2013-01-01

    Although bone marrow is the main source, mesenchymal stem cells have already been isolated from various other tissues, such as the liver, pancreas, adipose tissue, peripheral blood and dental pulp. These plastic adherent cells are morphologically similar to fibroblasts and have a high proliferative potential. This special group of cells possesses two essential characteristics: self-renewal and differentiation, with appropriate stimuli, into various cell types. Mesenchymal stem cells are considered immunologically privileged, since they do not express costimulatory molecules, required for complete T cell activation, on their surface. Several studies have shown that these cells exert an immunosuppressive effect on cells from both innate and acquired immunity systems. Mesenchymal stem cells can regulate the immune response in vitro by inhibiting the maturation of dendritic cells, as well as by suppressing the proliferation and function of T and B lymphocytes and natural killer cells. These special properties of mesenchymal stem cells make them a promising strategy in the treatment of immune mediated disorders, such as graft-versus-host disease and autoimmune diseases, as well as in regenerative medicine. The understanding of immune regulation mechanisms of mesenchymal stem cells, and also those involved in the differentiation of these cells in various lineages is primordial for their successful and safe application in different areas of medicine. PMID:23580887

  10. LncRNAs in Stem Cells

    PubMed Central

    Hu, Shanshan; Shan, Ge

    2016-01-01

    Noncoding RNAs are critical regulatory factors in essentially all forms of life. Stem cells occupy a special position in cell biology and Biomedicine, and emerging results show that multiple ncRNAs play essential roles in stem cells. We discuss some of the known ncRNAs in stem cells such as embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, adult stem cells, and cancer stem cells with a focus on long ncRNAs. Roles and functional mechanisms of these lncRNAs are summarized, and insights into current and future studies are presented. PMID:26880946

  11. A Testa Extract of Black Soybean (Glycine max (L.) Merr.) suppresses Adipogenic Activity of Adipose-derived Stem Cells

    PubMed Central

    Jeon, Younmi; Lee, Myoungsook; Cheon, Yong-Pil

    2015-01-01

    Black soybean teata is helpful to preventing obesity through enhancing energy expenditure and suppressing accumulation in mesenteric adipose tissue. The ethanol testa-extract of Cheongja #3 black soybean (ETCBS) is also have similar effects on obesity. So far, it is not clear whether the ethanol testa extract of black soybean can have effect on the characters of subcutaneous adipose stem cells such as proliferation, activity, and adipogenicity. The doubling time was different between subcutaneous adipose-derived stem (ADS) and visceral ADS cells. By the in vitro culture and passage, the doubling time was increased both of them. The shape was not different between groups and their passages were not cause the change of shapes. In the case of visceral ADS cells, the doubling time was 62.3 h or 40.3 h in control or high fat diet administrated mice, respectively, but not modified in subcutaneous ADS cells. ETCBS administration caused of increased the doubling time from 62.3 h to 84.2 h. ETCBS had suppressive effects on the cellular activity of subcutaneous ADS cells. The intensity of Oil Red O staining was very faint in 100 and 200 μg/mL ETCBS treated groups. The amounts of accumulated triglyceride were also significantly low in 100 and 200 μg/mL treated groups. From these results we know that the doubling times and the effects of ETCBS are different by the anatomical origin of ADS cells. It also suggested that ETCBS may suppress the differentiation of subcutaneous ADS cells into the precursors and maturing of adipocytes. PMID:26973975

  12. A Testa Extract of Black Soybean (Glycine max (L.) Merr.) suppresses Adipogenic Activity of Adipose-derived Stem Cells.

    PubMed

    Jeon, Younmi; Lee, Myoungsook; Cheon, Yong-Pil

    2015-12-01

    Black soybean teata is helpful to preventing obesity through enhancing energy expenditure and suppressing accumulation in mesenteric adipose tissue. The ethanol testa-extract of Cheongja #3 black soybean (ETCBS) is also have similar effects on obesity. So far, it is not clear whether the ethanol testa extract of black soybean can have effect on the characters of subcutaneous adipose stem cells such as proliferation, activity, and adipogenicity. The doubling time was different between subcutaneous adipose-derived stem (ADS) and visceral ADS cells. By the in vitro culture and passage, the doubling time was increased both of them. The shape was not different between groups and their passages were not cause the change of shapes. In the case of visceral ADS cells, the doubling time was 62.3 h or 40.3 h in control or high fat diet administrated mice, respectively, but not modified in subcutaneous ADS cells. ETCBS administration caused of increased the doubling time from 62.3 h to 84.2 h. ETCBS had suppressive effects on the cellular activity of subcutaneous ADS cells. The intensity of Oil Red O staining was very faint in 100 and 200 μg/mL ETCBS treated groups. The amounts of accumulated triglyceride were also significantly low in 100 and 200 μg/mL treated groups. From these results we know that the doubling times and the effects of ETCBS are different by the anatomical origin of ADS cells. It also suggested that ETCBS may suppress the differentiation of subcutaneous ADS cells into the precursors and maturing of adipocytes.

  13. Stem cells: review and update.

    PubMed

    Sylvester, Karl G; Longaker, Michael T

    2004-01-01

    Regenerative medicine and emerging biotechnologies stand to revolutionize the practice of medicine. Advancements in stem cell biology, including embryonic and postnatal somatic stem cells, have made the prospect of tissue regeneration a potential clinical reality. Short of reproductive cloning, these same technologies, properly used, could allow for the creation of replacement tissue for the deficient host. To provide a concise review for surgeons on the current science and biology of stem cells, we surveyed the scientific literature, MEDLINE, and relevant political headlines that illuminate the stem cell discussion; the issues are summarized in this review. Building on this conceptual framework, the related issues of clinical promise and the political debate enveloping this emerging technology are examined. A basic understanding of stem cell biology is paramount to stay informed of this emerging technology and the national debate.

  14. Sustained activation of DNA damage response in irradiated apoptosis-resistant cells induces reversible senescence associated with mTOR downregulation and expression of stem cell markers

    PubMed Central

    Chitikova, Zhanna V; Gordeev, Serguei A; Bykova, Tatiana V; Zubova, Svetlana G; Pospelov, Valery A; Pospelova, Tatiana V

    2014-01-01

    Cells respond to genotoxic stress by activating the DNA damage response (DDR). When injury is severe or irreparable, cells induce apoptosis or cellular senescence to prevent transmission of the lesions to the daughter cells upon cell division. Resistance to apoptosis is a hallmark of cancer that challenges the efficacy of cancer therapy. In this work, the effects of ionizing radiation on apoptosis-resistant E1A + E1B transformed cells were investigated to ascertain whether the activation of cellular senescence could provide an alternative tumor suppressor mechanism. We show that irradiated cells arrest cell cycle at G2/M phase and resume DNA replication in the absence of cell division followed by formation of giant polyploid cells. Permanent activation of DDR signaling due to impaired DNA repair results in the induction of cellular senescence in E1A + E1B cells. However, irradiated cells bypass senescence and restore the population by dividing cells, which have near normal size and ploidy and do not express senescence markers. Reversion of senescence and appearance of proliferating cells were associated with downregulation of mTOR, activation of autophagy, mitigation of DDR signaling, and expression of stem cell markers. PMID:24626185

  15. Stem Cells, Retinal Ganglion Cells, and Glaucoma

    PubMed Central

    Sluch, Valentin M.; Zack, Donald J.

    2015-01-01

    Retinal ganglion cells represent an essential neuronal cell type for vision. These cells receive inputs from light-sensing photoreceptors via retinal interneurons and then relay these signals to the brain for further processing. Retinal ganglion cell diseases that result in cell death, e.g. glaucoma, often lead to permanent damage since mammalian nerves do not regenerate. Stem cell differentiation can generate cells needed for replacement or can be used to generate cells capable of secreting protective factors to promote survival. In addition, stem cell-derived cells can be used in drug screening research. Here, we discuss the current state of stem cell research potential for interference in glaucoma and other optic nerve diseases with a focus on stem cell differentiation to retinal ganglion cells. PMID:24732765

  16. Histone modifications and p53 binding poise the p21 promoter for activation in human embryonic stem cells

    PubMed Central

    Itahana, Yoko; Zhang, Jinqiu; Göke, Jonathan; Vardy, Leah A.; Han, Rachel; Iwamoto, Kozue; Cukuroglu, Engin; Robson, Paul; Pouladi, Mahmoud A.; Colman, Alan; Itahana, Koji

    2016-01-01

    The high proliferation rate of embryonic stem cells (ESCs) is thought to arise partly from very low expression of p21. However, how p21 is suppressed in ESCs has been unclear. We found that p53 binds to the p21 promoter in human ESCs (hESCs) as efficiently as in differentiated human mesenchymal stem cells, however it does not promote p21 transcription in hESCs. We observed an enrichment for both the repressive histone H3K27me3 and activating histone H3K4me3 chromatin marks at the p21 locus in hESCs, suggesting it is a suppressed, bivalent domain which overrides activation by p53. Reducing H3K27me3 methylation in hESCs rescued p21 expression, and ectopic expression of p21 in hESCs triggered their differentiation. Further, we uncovered a subset of bivalent promoters bound by p53 in hESCs that are similarly induced upon differentiation in a p53-dependent manner, whereas p53 promotes the transcription of other target genes which do not show an enrichment of H3K27me3 in ESCs. Our studies reveal a unique epigenetic strategy used by ESCs to poise undesired p53 target genes, thus balancing the maintenance of pluripotency in the undifferentiated state with a robust response to differentiation signals, while utilizing p53 activity to maintain genomic stability and homeostasis in ESCs. PMID:27346849

  17. Histone modifications and p53 binding poise the p21 promoter for activation in human embryonic stem cells.

    PubMed

    Itahana, Yoko; Zhang, Jinqiu; Göke, Jonathan; Vardy, Leah A; Han, Rachel; Iwamoto, Kozue; Cukuroglu, Engin; Robson, Paul; Pouladi, Mahmoud A; Colman, Alan; Itahana, Koji

    2016-06-27

    The high proliferation rate of embryonic stem cells (ESCs) is thought to arise partly from very low expression of p21. However, how p21 is suppressed in ESCs has been unclear. We found that p53 binds to the p21 promoter in human ESCs (hESCs) as efficiently as in differentiated human mesenchymal stem cells, however it does not promote p21 transcription in hESCs. We observed an enrichment for both the repressive histone H3K27me3 and activating histone H3K4me3 chromatin marks at the p21 locus in hESCs, suggesting it is a suppressed, bivalent domain which overrides activation by p53. Reducing H3K27me3 methylation in hESCs rescued p21 expression, and ectopic expression of p21 in hESCs triggered their differentiation. Further, we uncovered a subset of bivalent promoters bound by p53 in hESCs that are similarly induced upon differentiation in a p53-dependent manner, whereas p53 promotes the transcription of other target genes which do not show an enrichment of H3K27me3 in ESCs. Our studies reveal a unique epigenetic strategy used by ESCs to poise undesired p53 target genes, thus balancing the maintenance of pluripotency in the undifferentiated state with a robust response to differentiation signals, while utilizing p53 activity to maintain genomic stability and homeostasis in ESCs.

  18. Histone modifications and p53 binding poise the p21 promoter for activation in human embryonic stem cells.

    PubMed

    Itahana, Yoko; Zhang, Jinqiu; Göke, Jonathan; Vardy, Leah A; Han, Rachel; Iwamoto, Kozue; Cukuroglu, Engin; Robson, Paul; Pouladi, Mahmoud A; Colman, Alan; Itahana, Koji

    2016-01-01

    The high proliferation rate of embryonic stem cells (ESCs) is thought to arise partly from very low expression of p21. However, how p21 is suppressed in ESCs has been unclear. We found that p53 binds to the p21 promoter in human ESCs (hESCs) as efficiently as in differentiated human mesenchymal stem cells, however it does not promote p21 transcription in hESCs. We observed an enrichment for both the repressive histone H3K27me3 and activating histone H3K4me3 chromatin marks at the p21 locus in hESCs, suggesting it is a suppressed, bivalent domain which overrides activation by p53. Reducing H3K27me3 methylation in hESCs rescued p21 expression, and ectopic expression of p21 in hESCs triggered their differentiation. Further, we uncovered a subset of bivalent promoters bound by p53 in hESCs that are similarly induced upon differentiation in a p53-dependent manner, whereas p53 promotes the transcription of other target genes which do not show an enrichment of H3K27me3 in ESCs. Our studies reveal a unique epigenetic strategy used by ESCs to poise undesired p53 target genes, thus balancing the maintenance of pluripotency in the undifferentiated state with a robust response to differentiation signals, while utilizing p53 activity to maintain genomic stability and homeostasis in ESCs. PMID:27346849

  19. Gastrointestinal stem cell up-to-date.

    PubMed

    Pirvulet, V

    2015-01-01

    Cellular and tissue regeneration in the gastrointestinal tract depends on stem cells with properties of self-renewal, clonogenicity, and multipotency. Progress in stem cell research and the identification of potential gastric, intestinal, colonic stem cells new markers and the signaling pathways provide hope for the use of stem cells in regenerative medicine and treatments for disease. This review provides an overview of the different types of stem cells, focusing on tissue-restricted adult stem cells.

  20. Translational findings from cardiovascular stem cell research.

    PubMed

    Mazhari, Ramesh; Hare, Joshua M

    2012-01-01

    The possibility of using stem cells to regenerate damaged myocardium has been actively investigated since the late 1990s. Consistent with the traditional view that the heart is a "postmitotic" organ that possesses minimal capacity for self-repair, much of the preclinical and clinical work has focused exclusively on introducing stem cells into the heart, with the hope of differentiation of these cells into functioning cardiomyocytes. This approach is ongoing and retains promise but to date has yielded inconsistent successes. More recently, it has become widely appreciated that the heart possesses endogenous repair mechanisms that, if adequately stimulated, might regenerate damaged cardiac tissue from in situ cardiac stem cells. Accordingly, much recent work has focused on engaging and enhancing endogenous cardiac repair mechanisms. This article reviews the literature on stem cell-based myocardial regeneration, placing emphasis on the mutually enriching interaction between basic and clinical research.

  1. Translational Findings from Cardiovascular Stem Cell Research

    PubMed Central

    Mazhari, Ramesh; Hare, Joshua M

    2012-01-01

    The possibility of using stem cells to regenerate damaged myocardium has been actively investigated since the late 1990s. Consistent with the traditional view that the heart is a “post-mitotic” organ that possesses minimal capacity for self-repair, much of the preclinical and clinical work has focused exclusively on introducing stem cells into the heart, with the hope of differentiation of these cells into functioning cardiomyocytes. This approach is ongoing and retains promise but to date has yielded inconsistent successes. More recently, it has become widely appreciated that the heart possesses endogenous repair mechanisms that, if adequately stimulated, might regenerate damaged cardiac tissue from in situ cardiac stem cells. Accordingly, much recent work has focused on engaging and enhancing endogenous cardiac repair mechanisms. This article reviews the literature on stem-cell based myocardial regeneration, placing emphasis on the mutually enriching interaction between basic and clinical research. PMID:22940024

  2. Two subpopulations of stem cells for T cell lineage

    SciTech Connect

    Katsura, Y.; Amagai, T.; Kina, T.; Sado, T.; Nishikawa, S.

    1985-11-01

    An assay system for the stem cell that colonizes the thymus and differentiates into T cells was developed, and by using this assay system the existence of two subpopulations of stem cells for T cell lineage was clarified. Part-body-shielded and 900-R-irradiated C57BL/6 (H-2b, Thy-1.2) recipient mice, which do not require the transfer of pluripotent stem cells for their survival, were transferred with cells from B10 X Thy-1.1 (H-2b, Thy-1.1) donor mice. The reconstitution of the recipient's thymus lymphocytes was accomplished by stem cells in the donor cells and those spared in the shielded portion of the recipient that competitively colonize the thymus. Thus, the stem cell activity of donor cells can be evaluated by determining the proportion of donor-type (Thy-1.1+) cells in the recipient's thymus. Bone marrow cells were the most potent source of stem cells. By contrast, when the stem cell activity was compared between spleen and bone marrow cells of whole-body-irradiated (800 R) C57BL/6 mice reconstituted with B10 X Thy-1.1 bone marrow cells by assaying in part-body-shielded and irradiated C57BL/6 mice, the activity of these two organs showed quite a different time course of development. The results strongly suggest that the stem cells for T cell lineage in the bone marrow comprise at least two subpopulations, spleen-seeking and bone marrow-seeking cells.

  3. Novel Regenerative Peptide TP508 Mitigates Radiation-Induced Gastrointestinal Damage By Activating Stem Cells and Preserving Crypt Integrity

    PubMed Central

    Kantara, Carla; Moya, Stephanie M.; Houchen, Courtney W.; Umar, Shahid; Ullrich, Robert L.; Singh, Pomila; Carney, Darrell H.

    2015-01-01

    In recent years, increasing threats of radiation exposure and nuclear disasters have become a significant concern for the United States and countries worldwide. Exposure to high doses of radiation triggers a number of potentially lethal effects. Among the most severe is the gastrointestinal (GI) toxicity syndrome caused by the destruction of the intestinal barrier, resulting in bacterial translocation, systemic bacteremia, sepsis and death. The lack of effective radioprotective agents capable of mitigating radiation-induced damage has prompted a search for novel countermeasures that can mitigate the effects of radiation post-exposure, accelerate tissue repair in radiation-exposed individuals, and prevent mortality. We report that a single injection of regenerative peptide TP508 (rusalatide acetate, Chrysalin®) 24h after lethal radiation exposure (9Gy, LD100/15) appears to significantly increase survival and delay mortality by mitigating radiation-induced intestinal and colonic toxicity. TP508 treatment post-exposure prevents the disintegration of gastrointestinal crypts, stimulates the expression of adherens junction protein E-cadherin, activates crypt cell proliferation, and decreases apoptosis. TP508 post-exposure treatment also up-regulates the expression of DCLK1 and LGR5 markers of stem cells that have been shown to be responsible for maintaining and regenerating intestinal crypts. Thus, TP508 appears to mitigate the effects of GI toxicity by activating radioresistant stem cells and increasing the stemness potential of crypts to maintain and restore intestinal integrity. These results suggest that TP508 may be an effective emergency nuclear countermeasure that could be delivered within 24h post-exposure to increase survival and delay mortality, giving victims time to reach clinical sites for advanced medical treatment. PMID:26280221

  4. Activation of the Extracellular Signal-Regulated Kinase Signaling Is Critical for Human Umbilical Cord Mesenchymal Stem Cell Osteogenic Differentiation

    PubMed Central

    Li, Chen-Shuang; Zheng, Zhong; Su, Xiao-Xia; Wang, Fei; Ling, Michelle; Zou, Min; Zhou, Hong

    2016-01-01

    Human umbilical cord mesenchymal stem cells (hUCMSCs) are recognized as candidate progenitor cells for bone regeneration. However, the mechanism of hUCMSC osteogenesis remains unclear. In this study, we revealed that mitogen-activated protein kinases (MAPKs) signaling is involved in hUCMSC osteogenic differentiation in vitro. Particularly, the activation of c-Jun N-terminal kinases (JNK) and p38 signaling pathways maintained a consistent level in hUCMSCs through the entire 21-day osteogenic differentiation period. At the same time, the activation of extracellular signal-regulated kinases (ERK) signaling significantly increased from day 5, peaked at day 9, and declined thereafter. Moreover, gene profiling of osteogenic markers, alkaline phosphatase (ALP) activity measurement, and alizarin red staining demonstrated that the application of U0126, a specific inhibitor for ERK activation, completely prohibited hUCMSC osteogenic differentiation. However, when U0126 was removed from the culture at day 9, ERK activation and osteogenic differentiation of hUCMSCs were partially recovered. Together, these findings demonstrate that the activation of ERK signaling is essential for hUCMSC osteogenic differentiation, which points out the significance of ERK signaling pathway to regulate the osteogenic differentiation of hUCMSCs as an alternative cell source for bone tissue engineering. PMID:26989682

  5. Keratinocyte stem cells: a commentary.

    PubMed

    Potten, Christopher S; Booth, Catherine

    2002-10-01

    For many years it has been widely accepted that stem cells play a crucial role in adult tissue maintenance. The concept that the renewing tissues of the body contain a small subcompartment of self-maintaining stem cells, upon which the entire tissue is dependent, is also now accepted as applicable to all renewing tissues. Gene therapy and tissue engineering are driving considerable interest in the clinical application of such hierarchically organized cellular compartments. Recent initial observations have provided a tantalizing insight into the large pluripotency of these cells. Indeed, scientists are now beginning to talk about the possible totipotency of some adult tissue stem cells. Such work is currently phenomenologic, but analysis of data derived from genomics and proteomics, identifying the crucial control signals involved, will soon provide a further impetus to stem cell biology with far reaching applications. The epidermis with its relatively simple structure, ease of accessibility, and the ability to grow its cells in vitro is one obvious target tissue for testing stem cell manipulation theories. It is crucial, however, that the normal keratinocyte stem cell is thoroughly characterized prior to attempting to manipulate its pluripotency. This commentary assesses the data generated to date and critically discusses the conclusions that have been drawn. Our current level of understanding, or lack of understanding, of the keratinocyte stem cell is reviewed.

  6. An activated form of ADAM10 is tumor selective and regulates cancer stem-like cells and tumor growth.

    PubMed

    Atapattu, Lakmali; Saha, Nayanendu; Chheang, Chanly; Eissman, Moritz F; Xu, Kai; Vail, Mary E; Hii, Linda; Llerena, Carmen; Liu, Zhanqi; Horvay, Katja; Abud, Helen E; Kusebauch, Ulrike; Moritz, Robert L; Ding, Bi-Sen; Cao, Zhongwei; Rafii, Shahin; Ernst, Matthias; Scott, Andrew M; Nikolov, Dimitar B; Lackmann, Martin; Janes, Peter W

    2016-08-22

    The transmembrane metalloprotease ADAM10 sheds a range of cell surface proteins, including ligands and receptors of the Notch, Eph, and erbB families, thereby activating signaling pathways critical for tumor initiation and maintenance. ADAM10 is thus a promising therapeutic target. Although widely expressed, its activity is normally tightly regulated. We now report prevalence of an active form of ADAM10 in tumors compared with normal tissues, in mouse models and humans, identified by our conformation-specific antibody mAb 8C7. Structure/function experiments indicate mAb 8C7 binds an active conformation dependent on disulfide isomerization and oxidative conditions, common in tumors. Moreover, this active ADAM10 form marks cancer stem-like cells with active Notch signaling, known to mediate chemoresistance. Importantly, specific targeting of active ADAM10 with 8C7 inhibits Notch activity and tumor growth in mouse models, particularly regrowth after chemotherapy. Our results indicate targeted inhibition of active ADAM10 as a potential therapy for ADAM10-dependent tumor development and drug resistance. PMID:27503072

  7. Mesenchymal stem cells promote colorectal cancer progression through AMPK/mTOR-mediated NF-κB activation

    PubMed Central

    Wu, Xiao-Bing; Liu, Yang; Wang, Gui-Hua; Xu, Xiao; Cai, Yang; Wang, Hong-Yi; Li, Yan-Qi; Meng, Hong-Fang; Dai, Fu; Jin, Ji-De

    2016-01-01

    Mesenchymal stem cells (MSCs) exert a tumor-promoting effect in a variety of human cancers. This study was designed to identify the molecular mechanisms related to the tumor-promoting effect of MSCs in colorectal cancer. In vitro analysis of colorectal cancer cell lines cultured in MSC conditioned media (MSC-CM) showed that MSC-CM significantly promoted the progression of the cancer cells by enhancing cell proliferation, migration and colony formation. The tumorigenic effect of MSC-CM was attributed to altered expression of cell cycle regulatory proteins and inhibition of apoptosis. Furthermore, MSC-CM induced high level expression of a number of pluripotency factors in the cancer cells. ELISAs revealed MSC-CM contained higher levels of IL-6 and IL-8, which are associated with the progression of cancer. Moreover, MSC-CM downregulated AMPK mRNA and protein phosphorylation, but upregulated mTOR mRNA and protein phosphorylation. The NF-κB pathway was activated after addition of MSC-CM. An in vivo model in Balb/C mice confirmed the ability of MSC-CM to promote the invasion and proliferation of colorectal cancer cells. This study indicates that MSCs promote the progression of colorectal cancer via AMPK/mTOR-mediated NF-κB activation. PMID:26892992

  8. Enhanced bradykinin-stimulated phospholipase C activity in murine embryonic stem cells lacking the G-protein alphaq-subunit.

    PubMed Central

    Ricupero, D A; Polgar, P; Taylor, L; Sowell, M O; Gao, Y; Bradwin, G; Mortensen, R M

    1997-01-01

    The gene coding for the G-protein alphaq subunit was interrupted by homologous recombination in murine embryonic stem cells (alphaq-null ES cells) as detected by Southern analysis and reverse-transcriptase PCR. The bradykinin (BK) B2 receptor was stably transfected into wild-type (WT) alphai-2-null and alphaq-null ES cells. The B2 receptor bound BK with high affinity and mobilized Ca2+. BK also activated phospholipase C (PLC), as determined by total inositol phosphate (IP) accumulation in a Bordetella pertussis toxin- and genistein-insensitive manner. In WT and alphai-2-null ES cells, BK increased IP levels approx. 4-fold above baseline. Most interestingly, in alphaq-null ES cells, BK increased IP accumulation approx. 9-fold above baseline. Re-expression of alphaq in alphaq-null ES cells resulted in normalization of the BK-stimulated IP accumulation (4-fold above baseline). These results suggest that the B2 receptor activates PLC through more than one member of the Gq family. Additionally, the absence of alphaq alters the kinetics of IP generation, which may reflect intrinsic characteristics of individual members of the Gq family or a decreased susceptibility to heterologous regulation in the alphaq-null ES cells, thus allowing for a more sustained generation of IP. PMID:9581559

  9. A Comparison of Culture Characteristics between Human Amniotic Mesenchymal Stem Cells and Dental Stem Cells.

    PubMed

    Yusoff, Nurul Hidayat; Alshehadat, Saaid Ayesh; Azlina, Ahmad; Kannan, Thirumulu Ponnuraj; Hamid, Suzina Sheikh Abdul

    2015-04-01

    In the past decade, the field of stem cell biology is of major interest among researchers due to its broad therapeutic potential. Stem cells are a class of undifferentiated cells that are able to differentiate into specialised cell types. Stem cells can be classified into two main types: adult stem cells (adult tissues) and embryonic stem cells (embryos formed during the blastocyst phase of embryological development). This review will discuss two types of adult mesenchymal stem cells, dental stem cells and amniotic stem cells, with respect to their differentiation lineages, passage numbers and animal model studies. Amniotic stem cells have a greater number of differentiation lineages than dental stem cells. On the contrary, dental stem cells showed the highest number of passages compared to amniotic stem cells. For tissue regeneration based on animal studies, amniotic stem cells showed the shortest time to regenerate in comparison with dental stem cells.

  10. Cell rheology: Stressed-out stem cells

    NASA Astrophysics Data System (ADS)

    Holle, Andrew W.; Engler, Adam J.

    2010-01-01

    Experiments have shown that the physical characteristics of the matrix surrounding a stem cell can affect its behaviour. This picture gets further complicated by studies of stem cells and their differentiated counterparts that show that the cells' own softness also has a clear role in how they respond to stress.

  11. Human Induced Pluripotent Stem Cells Are Targets for Allogeneic and Autologous Natural Killer (NK) Cells and Killing Is Partly Mediated by the Activating NK Receptor DNAM-1

    PubMed Central

    Monecke, Sebastian; Cyganek, Lukas; Elsner, Leslie; Hübscher, Daniela; Walter, Lutz; Streckfuss-Bömeke, Katrin; Guan, Kaomei; Dressel, Ralf

    2015-01-01

    Human induced pluripotent stem cells (hiPSCs) could be used to generate autologous cells for therapeutic purposes, which are expected to be tolerated by the recipient. However, iPSC-derived grafts are at risk of giving rise to teratomas in the host, if residuals of tumorigenic cells are not rejected by the recipient. We have analyzed the susceptibility of hiPSC lines to allogeneic and autologous natural killer (NK) cells. IL-2-activated, in contrast to resting NK cells killed hiPSC lines efficiently (P=1.69x10-39). Notably, the specific lysis of the individual hiPSC lines by IL-2-activated NK cells was significantly different (P=1.72x10-6) and ranged between 46 % and 64 % in 51Cr-release assays when compared to K562 cells. The hiPSC lines were killed by both allogeneic and autologous NK cells although autologous NK cells were less efficient (P=8.63x10-6). Killing was partly dependent on the activating NK receptor DNAM-1 (P=8.22x10-7). The DNAM-1 ligands CD112 and CD155 as well as the NKG2D ligands MICA and MICB were expressed on the hiPSC lines. Low amounts of human leukocyte antigen (HLA) class I proteins, which serve as ligands for inhibitory and activating NK receptors were also detected. Thus, the susceptibility to NK cell killing appears to constitute a common feature of hiPSCs. Therefore, NK cells might reduce the risk of teratoma formation even after autologous transplantations of pluripotent stem cell-derived grafts that contain traces of pluripotent cells. PMID:25950680

  12. Bone regeneration and stem cells

    PubMed Central

    Arvidson, K; Abdallah, B M; Applegate, L A; Baldini, N; Cenni, E; Gomez-Barrena, E; Granchi, D; Kassem, M; Konttinen, Y T; Mustafa, K; Pioletti, D P; Sillat, T; Finne-Wistrand, A

    2011-01-01

    Abstract This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed. PMID:21129153

  13. [Advances in Lung Stem Cells and Lung Cancer Stem Cells].

    PubMed

    Yin, Huijing; Deng, Jiong

    2015-10-20

    Cancer stem cells (CSCs) are emerging as a hot topic for cancer research. Lung CSCs share many characteristics with normal lung stem cells (SCs), including self-renewal and multi-potency for differentiation. Many molecular markers expressed in various types of CSCs were also found in lung CSCs, such as CD133, CD44, aldehyde dehydrogenase (ALDH) and ATP-binding cassette sub-family G member 2 (ABCG2). Similarly, proliferation and expansion of lung CSCs are regulated not only by signal transduction pathways functioning in normal lung SCs, such as Notch, Hedgehog and Wnt pathways, but also by those acting in tumor cells, such as epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 3 (STAT3) and phosphatidylinositol 3 kinase (PI3K) pathways. As CSC plays an critical role in tumor recurrence, metastasis and drug-resistance, understanding the difference between lung CSCs and normal lung SCs, identifying and targeting CSC markers or related signaling pathways may increase the efficacy of therapy on lung cancer and improved survival of lung cancer patients.

  14. Stem cell therapy without the cells

    PubMed Central

    Maguire, Greg

    2013-01-01

    As an example of the burgeoning importance of stem cell therapy, this past month the California Institute for Regenerative Medicine (CIRM) has approved $70 million to create a new network of stem cell clinical trial centers. Much work in the last decade has been devoted to developing the use of autologous and allogeneic adult stem cell transplants to treat a number of conditions, including heart attack, dementia, wounds, and immune system-related diseases. The standard model teaches us that adult stem cells exists throughout most of the body and provide a means to regenerate and repair most tissues through replication and differentiation. Although we have often witnessed the medical cart placed in front of the scientific horse in the development of stem cell therapies outside of academic circles, great strides have been made, such as the use of purified stem cells1 instead of whole bone marrow transplants in cancer patients, where physicians avoid re-injecting the patients with their own cancer cells.2 We most often think of stem cell therapy acting to regenerate tissue through replication and then differentiation, but recent studies point to the dramatic effects adult stem cells exert in the repair of various tissues through the release of paracrine and autocrine substances, and not simply through differentiation. Indeed, up to 80% of the therapeutic effect of adult stem cells has been shown to be through paracrine mediated actions.3 That is, the collected types of molecules released by the stem cells, called the secretome, or stem cell released molecules (SRM), number in the 100s, including proteins, microRNA, growth factors, antioxidants, proteasomes, and exosomes, and target a multitude of biological pathways through paracrine actions. The composition of the different molecule types in SRM is state dependent, and varies with cell type and conditions such as age and environment. PMID:24567776

  15. FoxM1 Drives a Feed-forward STAT3-activation Signaling Loop that Promotes the Self-renewal and Tumorigenicity of Glioblastoma Stem-like Cells

    PubMed Central

    Gong, Ai-hua; Wei, Ping; Zhang, Sicong; Yao, Jun; Yuan, Ying; Zhou, Ai-dong; Lang, Frederick F.; Heimberger, Amy B.; Rao, Ganesh; Huang, Suyun

    2015-01-01

    The growth factor PDGF controls the development of glioblastoma (GBM) but its contribution to the function of GBM stem-like cells (GSC) has been little studied. Here we report that the transcription factor FoxM1 promotes PDGFA-STAT3 signaling to drive GSC self-renewal and tumorigenicity. In GBM we found a positive correlation between expression of FoxM1 and PDGF-A. In GSC and mouse neural stem cells, FoxM1 bound to the PDGF-A promoter to upregulate PDGF-A expression, acting to maintain the stem-like qualities of GSC in part through this mechanism. Analysis of the human cancer genomic database TCGA revealed that GBM express higher levels of STAT3, a PDGF-A effector signaling molecule, as compared with normal brain. FoxM1 regulated STAT3 transcription through interactions with the β-catenin/TCF4 complex. FoxM1 deficiency inhibited PDGF-A and STAT3 expression in neural stem cells and GSC, abolishing their stem-like and tumorigenic properties. Further mechanistic investigations defined a FoxM1-PDGFA-STAT3 feed-forward pathway that was sufficient to confer stem-like properties to glioma cells. Collectively, our findings showed how FoxM1 activates expression of PDGF-A and STAT3 in a pathway required to maintain the self-renewal and tumorigenicity of glioma stem-like cells. PMID:25832656

  16. Changes in lamina structure are followed by spatial reorganization of heterochromatic regions in caspase-8-activated human mesenchymal stem cells.

    PubMed

    Raz, Vered; Carlotti, Françoise; Vermolen, Bart J; van der Poel, Egge; Sloos, Willem C R; Knaän-Shanzer, Shoshan; de Vries, Antoine A F; Hoeben, Rob C; Young, Ian T; Tanke, Hans J; Garini, Yuval; Dirks, Roeland W

    2006-10-15

    Apoptosis is fundamental to the regulation of homeostasis of stem cells in vivo. Whereas the pathways underlying the molecular and biochemical details of nuclear breakdown that accompanies apoptosis have been elucidated, the precise nature of nuclear reorganization that precedes the demolition phase is not fully understood. Here, we expressed an inducible caspase-8 in human mesenchymal stem cells, and quantitatively followed the early changes in nuclear organization during apoptosis. We found that caspase-8 induces alteration of the nuclear lamina and a subsequent spatial reorganization of both centromeres, which are shifted towards a peripheral localization, and telomeres, which form aggregates. This nuclear reorganization correlates with caspase-3 sensitivity of lamina proteins, because the expression of lamin mutant constructs with caspase-3 hypersensitivity resulted in a caspase-8-independent appearance of lamina intranuclear structures and telomere aggregates, whereas application of a caspase inhibitor restrains these changes in nuclear reorganization. Notably, upon activation of apoptosis, we observed no initial changes in the spatial organization of the promyelocytic leukemia nuclear bodies (PML-NBs). We suggest that during activation of the caspase-8 pathway changes in the lamina structure precede changes in heterochromatin spatial organization, and the subsequent breakdown of lamina and PML-NB.

  17. Proton-sensing GPCR-YAP Signalling Promotes Cancer-associated Fibroblast Activation of Mesenchymal Stem Cells

    PubMed Central

    Zhu, Hongyi; Guo, Shangchun; Zhang, Yuelei; Yin, Junhui; Yin, Wenjing; Tao, Shicong; Wang, Yang; Zhang, Changqing

    2016-01-01

    The pHs of extracellular fluids (ECFs) in normal tissues are commonly maintained at 7.35 to 7.45. The acidification of the ECF is one of the major characteristics of tumour microenvironment. In this study, we report that decreased extracellular pH promotes the transformation of mesenchymal stem cells (MSCs) into cancer-associated fibroblasts (CAFs), termed CAF activation. Furthermore, we demonstrate that GPR68, a proton-sensing G-protein-coupled receptor (GPCR), is required for the pH-dependent regulation of the differentiation of MSCs into CAFs. We then identify Yes-associated protein 1 (YAP) as a downstream effector of GPR68 for CAF activation. Finally, we show that knockdown of GPR68 in MSCs can prevent the CAF activation under cancer microenvironment. Systemic transplantation of GPR68-silenced MSCs suppresses in-situ tumour growth and prolong life span after cancer graft. PMID:27019624

  18. Hypothermia augments neuroprotective activity of mesenchymal stem cells for neonatal hypoxic-ischemic encephalopathy.

    PubMed

    Park, Won Soon; Sung, Se In; Ahn, So Yoon; Yoo, Hye Soo; Sung, Dong Kyung; Im, Geun Ho; Choi, Soo Jin; Chang, Yun Sil

    2015-01-01

    Though hypothermia is the only clinically available treatment for neonatal hypoxic-ischemic encephalopathy (HIE), it is not completely effective in severe cases. We hypothesized that combined treatment with hypothermia and transplantation of human umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) would synergistically attenuate severe HIE compared to stand-alone therapy. To induce hypoxia-ischemia (HI), male Sprague-Dawley rats were subjected to 8% oxygen for 120 min after unilateral carotid artery ligation on postnatal day (P) 7. After confirmation of severe HIE involving >50% of the ipsilateral hemisphere volume as determined by diffusion-weighted brain magnetic resonance imaging (MRI) within 2 h after HI, intraventricular MSC transplantation (1 × 105 cells) and/or hypothermia with target temperature at 32°C for 24 h were administered 6 h after induction of HI. Follow-up brain MRI at P12 and P42, sensorimotor function tests at P40-42, evaluation of cytokines in the cerebrospinal fluid (CSF) at P42, and histologic analysis of peri-infarct tissues at P42 were performed. Severe HI resulted in progressively increased brain infarction over time as assessed by serial MRI, increased number of cells positive for terminal deoxynucleotidyl transferase nick-end labeling, microgliosis and astrocytosis, increased CSF cytokine levels, and impaired function in behavioral tests such as rotarod and cylinder tests. All of the abnormalities observed in severe HIE showed greater improvement after combined treatment with hypothermia and MSC transplantation than with either therapy alone. Overall, these findings suggest that combined treatment with hypothermia and human UCB-derived MSC transplantation might be a novel therapeutic modality to improve the prognosis of severe HIE, an intractable disease that currently has no effective treatment.

  19. Hypothermia augments neuroprotective activity of mesenchymal stem cells for neonatal hypoxic-ischemic encephalopathy.

    PubMed

    Park, Won Soon; Sung, Se In; Ahn, So Yoon; Yoo, Hye Soo; Sung, Dong Kyung; Im, Geun Ho; Choi, Soo Jin; Chang, Yun Sil

    2015-01-01

    Though hypothermia is the only clinically available treatment for neonatal hypoxic-ischemic encephalopathy (HIE), it is not completely effective in severe cases. We hypothesized that combined treatment with hypothermia and transplantation of human umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) would synergistically attenuate severe HIE compared to stand-alone therapy. To induce hypoxia-ischemia (HI), male Sprague-Dawley rats were subjected to 8% oxygen for 120 min after unilateral carotid artery ligation on postnatal day (P) 7. After confirmation of severe HIE involving >50% of the ipsilateral hemisphere volume as determined by diffusion-weighted brain magnetic resonance imaging (MRI) within 2 h after HI, intraventricular MSC transplantation (1 × 105 cells) and/or hypothermia with target temperature at 32°C for 24 h were administered 6 h after induction of HI. Follow-up brain MRI at P12 and P42, sensorimotor function tests at P40-42, evaluation of cytokines in the cerebrospinal fluid (CSF) at P42, and histologic analysis of peri-infarct tissues at P42 were performed. Severe HI resulted in progressively increased brain infarction over time as assessed by serial MRI, increased number of cells positive for terminal deoxynucleotidyl transferase nick-end labeling, microgliosis and astrocytosis, increased CSF cytokine levels, and impaired function in behavioral tests such as rotarod and cylinder tests. All of the abnormalities observed in severe HIE showed greater improvement after combined treatment with hypothermia and MSC transplantation than with either therapy alone. Overall, these findings suggest that combined treatment with hypothermia and human UCB-derived MSC transplantation might be a novel therapeutic modality to improve the prognosis of severe HIE, an intractable disease that currently has no effective treatment. PMID:25816095

  20. Regulation of breast cancer stem cell features.

    PubMed

    Czerwinska, Patrycja; Kaminska, Bozena

    2015-01-01

    Cancer stem cells (CSCs) are rare, tumour-initiating cells that exhibit stem cell properties: capacity of self-renewal, pluripotency, highly tumorigenic potential, and resistance to therapy. Cancer stem cells have been characterised and isolated from many cancers, including breast cancer. Developmental pathways, such as the Wnt/β-catenin, Notch/γ-secretase/Jagged, Shh (sonic hedgehog), and BMP signalling pathways, which direct proliferation and differentiation of normal stem cells, have emerged as major signalling pathways that contribute to the self-renewal of stem and/or progenitor cells in a variety of organs and cancers. Deregulation of these signalling pathways is frequently linked to an epithelial-mesenchymal transition (EMT), and breast CSCs often possess properties of cells that have undergone the EMT process. Signalling networks mediated by microRNAs and EMT-inducing transcription factors tie the EMT process to regulatory networks that maintain "stemness". Recent studies have elucidated epigenetic mechanisms that control pluripotency and stemness, which allows an assessment on how embryonic and normal tissue stem cells are deregulated during cancerogenesis to give rise to CSCs. Epigenetic-based mechanisms are reversible, and the possibility of "resetting" the abnormal cancer epigenome by applying pharmacological compounds targeting epigenetic enzymes is a promising new therapeutic strategy. Chemoresistance of CSCs is frequently driven by various mechanisms, including aberrant expression/activity of ABC transporters, aldehyde dehydrogenase and anti-oncogenic proteins (i.e. BCL2, B-cell lymphoma-2), enhanced DNA damage response, activation of pro-survival signalling pathways, and epigenetic deregulations. Despite controversy surrounding the CSC hypothesis, there is substantial evidence for their role in cancer, and a number of drugs intended to specifically target CSCs have entered clinical trials. PMID:25691826

  1. Post-thaw viability of cryopreserved peripheral blood stem cells (PBSC) does not guarantee functional activity: important implications for quality assurance of stem cell transplant programmes.

    PubMed

    Morgenstern, Daniel A; Ahsan, Gulrukh; Brocklesby, Margaret; Ings, Stuart; Balsa, Carmen; Veys, Paul; Brock, Penelope; Anderson, John; Amrolia, Persis; Goulden, Nicholas; Cale, Catherine M; Watts, Michael J

    2016-09-01

    Standard quality assurance (QA) of cryopreserved peripheral blood stem cells (PBSC) uses post-thaw viable CD34(+) cell counts. In 2013, concerns arose at Great Ormond Street Hospital (GOSH) about 8 patients with delayed engraftment following myeloablative chemotherapy with cryopreserved cell rescue, despite adequate post-thaw viable cell counts in all cases. Root cause analysis was undertaken; investigations suggested the freeze process itself was a contributing factor to suboptimal engraftment. Experiments were undertaken in which a single PBSC product was divided into three and cryopreserved in parallel using a control-rate freezer (CRF) or passive freezing method (-80°C freezer) at GOSH, or the same passive freezing at another laboratory. Viable CD34(+) counts were equivalent and adequate in each. Granulocyte-monocyte colony-forming unit assays demonstrated colonies from the products cryopreserved using passive freezing (both laboratories), but no colonies from products cryopreserved using the CRF. The CRF was shown to be operating within manufacturer's specifications with freeze-profile within acceptable limits. This experience has important implications for quality assurance for all transplant programmes, particularly those using cryopreserved products. The failure of post-thaw viable CD34(+) counts, the most widely used routine QA test available, to ensure PBSC function is of great concern and should prompt reassessment of protocols and QA procedures. PMID:27291859

  2. Post-thaw viability of cryopreserved peripheral blood stem cells (PBSC) does not guarantee functional activity: important implications for quality assurance of stem cell transplant programmes.

    PubMed

    Morgenstern, Daniel A; Ahsan, Gulrukh; Brocklesby, Margaret; Ings, Stuart; Balsa, Carmen; Veys, Paul; Brock, Penelope; Anderson, John; Amrolia, Persis; Goulden, Nicholas; Cale, Catherine M; Watts, Michael J

    2016-09-01

    Standard quality assurance (QA) of cryopreserved peripheral blood stem cells (PBSC) uses post-thaw viable CD34(+) cell counts. In 2013, concerns arose at Great Ormond Street Hospital (GOSH) about 8 patients with delayed engraftment following myeloablative chemotherapy with cryopreserved cell rescue, despite adequate post-thaw viable cell counts in all cases. Root cause analysis was undertaken; investigations suggested the freeze process itself was a contributing factor to suboptimal engraftment. Experiments were undertaken in which a single PBSC product was divided into three and cryopreserved in parallel using a control-rate freezer (CRF) or passive freezing method (-80°C freezer) at GOSH, or the same passive freezing at another laboratory. Viable CD34(+) counts were equivalent and adequate in each. Granulocyte-monocyte colony-forming unit assays demonstrated colonies from the products cryopreserved using passive freezing (both laboratories), but no colonies from products cryopreserved using the CRF. The CRF was shown to be operating within manufacturer's specifications with freeze-profile within acceptable limits. This experience has important implications for quality assurance for all transplant programmes, particularly those using cryopreserved products. The failure of post-thaw viable CD34(+) counts, the most widely used routine QA test available, to ensure PBSC function is of great concern and should prompt reassessment of protocols and QA procedures.

  3. Recruitment of Mediator Complex by Cell Type and Stage-Specific Factors Required for Tissue-Specific TAF Dependent Gene Activation in an Adult Stem Cell Lineage.

    PubMed

    Lu, Chenggang; Fuller, Margaret T

    2015-12-01

    Onset of terminal differentiation in adult stem cell lineages is commonly marked by robust activation of new transcriptional programs required to make the appropriate differentiated cell type(s). In the Drosophila male germ line stem cell lineage, the switch from proliferating spermatogonia to spermatocyte is accompanied by one of the most dramatic transcriptional changes in the fly, as over 1000 new transcripts turn on in preparation for meiosis and spermatid differentiation. Here we show that function of the coactivator complex Mediator is required for activation of hundreds of new transcripts in the spermatocyte program. Mediator appears to act in a sequential hierarchy, with the testis activating Complex (tMAC), a cell type specific form of the Mip/dREAM general repressor, required to recruit Mediator subunits to the chromatin, and Mediator function required to recruit the testis TAFs (tTAFs), spermatocyte specific homologs of subunits of TFIID. Mediator, tMAC and the tTAFs co-regulate expression of a major set of spermatid differentiation genes. The Mediator subunit Med22 binds the tMAC component Topi when the two are coexpressed in S2 cells, suggesting direct recruitment. Loss of Med22 function in spermatocytes causes meiosis I maturation arrest male infertility, similar to loss of function of the tMAC subunits or the tTAFs. Our results illuminate how cell type specific versions of the Mip/dREAM complex and the general transcription machinery cooperate to drive selective gene activation during differentiation in stem cell lineages. PMID:26624996

  4. Microbioreactors for Stem Cell Research

    NASA Astrophysics Data System (ADS)

    Freytes, Donald O.; Vunjak-Novakovic, Gordana

    During tissue development and regeneration, stem cells respond to the entire milieu of their environment, through dynamic interactions with the surrounding cells, extracellular matrix, and cascades of molecular and physical regulatory factors. A new generation of culture systems is emerging to offer some of the biological fidelity of a whole organism within highly controllable in vitro settings and provide the cultured cells with the combinations of factors they normally encounter in vivo. There is a growing notion that such "biomimetic" systems are essential for unlocking the full potential of stem cells - for tissue regeneration as well as biological research. In this chapter, we discuss the biological principles for designing biologically inspired culture systems for stem cell research and focus on the control of stem cell microenvironment through surface patterning, microfluidics, and electrical stimulation.

  5. Stem cells and combinatorial science.

    PubMed

    Fang, Yue Qin; Wong, Wan Qing; Yap, Yan Wen; Orner, Brendan P

    2007-09-01

    Stem cell-based technologies have the potential to help cure a number of cell degenerative diseases. Combinatorial and high throughput screening techniques could provide tools to control and manipulate the self-renewal and differentiation of stem cells. This review chronicles historic and recent progress in the stem cell field involving both pluripotent and multipotent cells, and it highlights relevant cellular signal transduction pathways. This review further describes screens using libraries of soluble, small-molecule ligands, and arrays of molecules immobilized onto surfaces while proposing future trends in similar studies. It is hoped that by reviewing both the stem cell and the relevant high throughput screening literature, this paper can act as a resource to the combinatorial science community.

  6. Nuclear receptors in stem cell biology.

    PubMed

    Shi, Yanhong; Sun, Guoqiang; Stewart, Richard

    2006-01-01

    Batteries of transcription factors have been proposed to control stem cell self-renewal and lineage progression by eliciting cascades of gene expression. Nuclear receptors provide an ideal model to study the transcriptional regulation of gene expression because they can activate as well as repress gene expression through ligand binding and recruitment of transcriptional coactivators or corepressors. Recent progress in defining specific roles of some nuclear receptors and their coregulators in stem cell self-renewal and differentiation provides a first glimpse of the regulatory events involved and is the beginning of a very promising area of research. This review summarizes the current state of knowledge regarding nuclear receptors and their roles in stem cell biology. These studies not only facilitate an understanding of stem cell biology but also provide a basis for the development of therapeutic drugs for the treatment of a variety of diseases.

  7. Will embryonic stem cells change health policy?

    PubMed

    Sage, William M

    2010-01-01

    Embryonic stem cells are actively debated in political and public policy arenas. However, the connections between stem cell innovation and overall health care policy are seldom elucidated. As with many controversial aspects of medical care, the stem cell debate bridges to a variety of social conversations beyond abortion. Some issues, such as translational medicine, commercialization, patient and public safety, health care spending, physician practice, and access to insurance and health care services, are core health policy concerns. Other issues, such as economic development, technologic progress, fiscal politics, and tort reform, are only indirectly related to the health care system but are frequently seen through a health care lens. These connections will help determine whether the stem cell debate reaches a resolution, and what that resolution might be. PMID:20579256

  8. Will embryonic stem cells change health policy?

    PubMed

    Sage, William M

    2010-01-01

    Embryonic stem cells are actively debated in political and public policy arenas. However, the connections between stem cell innovation and overall health care policy are seldom elucidated. As with many controversial aspects of medical care, the stem cell debate bridges to a variety of social conversations beyond abortion. Some issues, such as translational medicine, commercialization, patient and public safety, health care spending, physician practice, and access to insurance and health care services, are core health policy concerns. Other issues, such as economic development, technologic progress, fiscal politics, and tort reform, are only indirectly related to the health care system but are frequently seen through a health care lens. These connections will help determine whether the stem cell debate reaches a resolution, and what that resolution might be.

  9. Selective Cytotoxicity and Pro-apoptotic Activity of Stem Bark of Wrightia tinctoria (Roxb.) R. Br. in Cancerous Cells

    PubMed Central

    Chaudhary, Shilpee; Devkar, Raviraj Anand; Bhere, Deepak; Setty, Manganahalli Manjunath; Pai, Karkala Sreedhara Ranganath

    2015-01-01

    Background: Wrightia tinctoria (Roxb.) R. Br. is a widely available shrub in India used traditionally in various ailments, including cancer. However, the anticancer activity of the bioactive fractions has not been validated scientifically. Objective: To investigate the anticancer potential of stem bark of W. tinctoria and establish its phytochemical basis. Materials and Methods: The ethanol extract and subsequent fractions, petroleum ether, ethyl acetate, n-butanol, and aqueous were prepared by standard methods. In vitro cytotoxicity was determined in MCF-7 (breast) and HeLa (cervical) adenocarcinoma cells, and V79 (nontumor fibroblast) cells and apoptogenic activity in MCF-7 cells by acridine orange (AO)/ethidium bromide (EB) staining. Additionally, the antioxidant potential was evaluated using suitable methods. High-performance thin layer chromatography (HPTLC) analysis was performed for identification of active phytoconstituents. Results: Petroleum ether and ethyl acetate fractions were most potent with IC50 values of 37.78 and 29.69 μg/ml in HeLa and 31.56 and 32.63 μg/ml in MCF-7 cells respectively in the sulforhodamine B assay. Comparable results were obtained in HeLa cells in 3-(4,5-dimethylthiazolyl-2-yl)-2,5-diphenyl tetrazolium bromide assay and interestingly, the fractions were found to be safe to noncancerous fibroblast cells. Both fractions induced significant (P < 0.05) apoptotic morphological changes observed by AO/EB staining. Moreover, extract/fractions exhibited excellent inhibition of lipid peroxidation with the ethyl acetate fraction being most active (IC50:23.40 μg/ml). HPTLC confirmed the presence of two anti-cancer triterpenoids, lupeol, and β-sitosterol in active fractions. Conclusion: Extract/fractions of W. tinctoria exhibit selective cytotoxicity against cancerous cells that is mediated by apoptosis. Fractions are less toxic to noncancerous cells; hence, they can be developed as safer chemopreventive agents. SUMMARY Petroleum ether

  10. The embryonic stem cell test.

    PubMed

    Schulpen, Sjors H W; Piersma, Aldert H

    2013-01-01

    The embryonic stem cell test is an animal-free alternative test method for developmental toxicity. Mouse embryonic stem cells are cultured in a hanging drop method to form embryoid bodies. These embryoid bodies, when plated on tissue culture dishes, differentiate to form contracting myocardial cell foci within 10 days. Inhibition of cardiomyocyte differentiation by test compounds serves as the end point of the assay, as monitored by counting contracting muscle foci under the microscope.

  11. Scaling down the size and increasing the throughput of glycosyltransferase assays: activity changes on stem cell differentiation.

    PubMed

    Patil, Shilpa A; Chandrasekaran, E V; Matta, Khushi L; Parikh, Abhirath; Tzanakakis, Emmanuel S; Neelamegham, Sriram

    2012-06-15

    Glycosyltransferases (glycoTs) catalyze the transfer of monosaccharides from nucleotide-sugars to carbohydrate-, lipid-, and protein-based acceptors. We examined strategies to scale down and increase the throughput of glycoT enzymatic assays because traditional methods require large reaction volumes and complex chromatography. Approaches tested used (i) microarray pin printing, an appropriate method when glycoT activity was high; (ii) microwells and microcentrifuge tubes, a suitable method for studies with cell lysates when enzyme activity was moderate; and (iii) C(18) pipette tips and solvent extraction, a method that enriched reaction product when the extent of reaction was low. In all cases, reverse-phase thin layer chromatography (RP-TLC) coupled with phosphorimaging quantified the reaction rate. Studies with mouse embryonic stem cells (mESCs) demonstrated an increase in overall β(1,3)galactosyltransferase and α(2,3)sialyltransferase activity and a decrease in α(1,3)fucosyltransferases when these cells differentiate toward cardiomyocytes. Enzymatic and lectin binding data suggest a transition from Lewis(x)-type structures in mESCs to sialylated Galβ1,3GalNAc-type glycans on differentiation, with more prominent changes in enzyme activity occurring at later stages when embryoid bodies differentiated toward cardiomyocytes. Overall, simple, rapid, quantitative, and scalable glycoT activity analysis methods are presented. These use a range of natural and synthetic acceptors for the analysis of complex biological specimens that have limited availability.

  12. In vivo tracking of T cells in humans unveils decade-long survival and activity of genetically modified T memory stem cells.

    PubMed

    Biasco, Luca; Scala, Serena; Basso Ricci, Luca; Dionisio, Francesca; Baricordi, Cristina; Calabria, Andrea; Giannelli, Stefania; Cieri, Nicoletta; Barzaghi, Federica; Pajno, Roberta; Al-Mousa, Hamoud; Scarselli, Alessia; Cancrini, Caterina; Bordignon, Claudio; Roncarolo, Maria Grazia; Montini, Eugenio; Bonini, Chiara; Aiuti, Alessandro

    2015-02-01

    A definitive understanding of survival and differentiation potential in humans of T cell subpopulations is of paramount importance for the development of effective T cell therapies. In particular, uncovering the dynamics in vivo in humans of the recently described T memory stem cells (TSCM) would be crucial for therapeutic approaches that aim at taking advantage of a stable cellular vehicle with precursor potential. We exploited data derived from two gene therapy clinical trials for an inherited immunodeficiency, using either retrovirally engineered hematopoietic stem cells or mature lymphocytes to trace individual T cell clones directly in vivo in humans. We compared healthy donors and bone marrow-transplanted patients, studied long-term in vivo T cell composition under different clinical conditions, and specifically examined TSCM contribution according to age, conditioning regimen, disease background, cell source, long-term reconstitution, and ex vivo gene correction processing. High-throughput sequencing of retroviral vector integration sites (ISs) allowed tracing the fate of more than 1700 individual T cell clones in gene therapy patients after infusion of gene-corrected hematopoietic stem cells or mature lymphocytes. We shed light on long-term in vivo clonal relationships among different T cell subtypes, and we unveiled that TSCM are able to persist and to preserve their precursor potential in humans for up to 12 years after infusion of gene-corrected lymphocytes. Overall, this work provides high-resolution tracking of T cell fate and activity and validates, in humans, the safe and functional decade-long survival of engineered TSCM, paving the way for their future application in clinical settings.

  13. Acute GVHD in patients receiving IL-15/4-1BBL activated NK cells following T-cell–depleted stem cell transplantation

    PubMed Central

    Shah, Nirali N.; Baird, Kristin; Delbrook, Cynthia P.; Fleisher, Thomas A.; Kohler, Mark E.; Rampertaap, Shakuntala; Lemberg, Kimberly; Hurley, Carolyn K.; Kleiner, David E.; Merchant, Melinda S.; Pittaluga, Stefania; Sabatino, Marianna; Stroncek, David F.; Wayne, Alan S.; Zhang, Hua; Fry, Terry J.

    2015-01-01

    Natural killer (NK) cells can enhance engraftment and mediate graft-versus-leukemia following allogeneic hematopoietic stem cell transplantation (HSCT), but the potency of graft-versus-leukemia mediated by naturally reconstituting NK cells following HSCT is limited. Preclinical studies demonstrate that activation of NK cells using interleukin-15 (IL-15) plus 4-1BBL upregulates activating receptor expression and augments killing capacity. In an effort to amplify the beneficial effects of NK cells post-HSCT, we conducted a first-in-human trial of adoptive transfer of donor-derived IL-15/4-1BBL–activated NK cells (aNK-DLI) following HLA-matched, T-cell–depleted (1-2 × 104 T cells/kg) nonmyeloablative peripheral blood stem cell transplantation in children and young adults with ultra-high-risk solid tumors. aNK-DLI were CD3+-depleted, CD56+-selected lymphocytes, cultured for 9 to 11 days with recombinant human IL-15 plus 4-1BBL+IL-15Rα+ artificial antigen-presenting cells. aNK-DLI demonstrated potent killing capacity and displayed high levels of activating receptor expression. Five of 9 transplant recipients experienced acute graft-versus-host disease (GVHD) following aNK-DLI, with grade 4 GVHD observed in 3 subjects. GVHD was more common in matched unrelated donor vs matched sibling donor recipients and was associated with higher donor CD3 chimerism. Given that the T-cell dose was below the threshold required for GVHD in this setting, we conclude that aNK-DLI contributed to the acute GVHD observed, likely by augmenting underlying T-cell alloreactivity. This trial was registered at www.clinicaltrials.gov as #NCT01287104. PMID:25452614

  14. Harvesting dental stem cells - Overview

    PubMed Central

    Sunil, P. M.; Manikandan, Ramanathan; Muthumurugan; Yoithapprabhunath, Thukanayakanpalayam Ragunathan; Sivakumar, Muniapillai

    2015-01-01

    Dental stem cells have recently become one of the widely researched areas in dentistry. Ever since the identification of stem cells from various dental tissues like deciduous teeth, dental papilla, periodontal ligament and third molars, storing them for future use for various clinical applications was being explored. Dental stem cells were harvested and isolated using various techniques by different investigators and laboratories. This article explains the technical aspects of preparing the patient, atraumatic and aseptic removal of the tooth and its safe transportation and preservation for future expansion. PMID:26538883

  15. Stem cells, dot-com.

    PubMed

    Liang, Bryan A; Mackey, Tim K

    2012-09-12

    Direct-to-consumer (DTC) advertising of suspect goods and services has burgeoned because of the Internet. Despite very limited approval for use, DTC stem cell-marketed "treatments" have emerged for an array of conditions, creating global public health and safety risks. However, it remains unclear whether such use of stem cells is subject to drugs or biologics regulations. To address this gap, regulatory agencies should be given clear authority, and the international community should create a framework for appropriate stem cell use. In addition, consumer protection laws should be used to scrutinize providers.

  16. Telomeres, stem cells, and hematology

    PubMed Central

    2008-01-01

    Telomeres are highly dynamic structures that adjust the cellular response to stress and growth stimulation based on previous cell divisions. This critical function is accomplished by progressive telomere shortening and DNA damage responses activated by chromosome ends without sufficient telomere repeats. Repair of critically short telomeres by telomerase or recombination is limited in most somatic cells, and apoptosis or cellular senescence is triggered when too many uncapped telomeres accumulate. The chance of the latter increases as the average telomere length decreases. The average telomere length is set and maintained in cells of the germ line that typically express high levels of telomerase. In somatic cells, the telomere length typically declines with age, posing a barrier to tumor growth but also contributing to loss of cells with age. Loss of (stem) cells via telomere attrition provides strong selection for abnormal cells in which malignant progression is facilitated by genome instability resulting from uncapped telomeres. The critical role of telomeres in cell proliferation and aging is illustrated in patients with 50% of normal telomerase levels resulting from a mutation in one of the telomerase genes. Here, the role of telomeres and telomerase in human biology is reviewed from a personal historical perspective. PMID:18263784

  17. Activation of two distinct Sox9-EGFP-expressing intestinal stem cell populations during crypt regeneration after irradiation

    PubMed Central

    Van Landeghem, Laurianne; Santoro, M. Agostina; Krebs, Adrienne E.; Mah, Amanda T.; Dehmer, Jeffrey J.; Gracz, Adam D.; Scull, Brooks P.; McNaughton, Kirk; Magness, Scott T.

    2012-01-01

    Recent identification of intestinal epithelial stem cell (ISC) markers and development of ISC reporter mice permit visualization and isolation of regenerating ISCs after radiation to define their functional and molecular phenotypes. Previous studies in uninjured intestine of Sox9-EGFP reporter mice demonstrate that ISCs express low levels of Sox9-EGFP (Sox9-EGFP Low), whereas enteroendocrine cells (EEC) express high levels of Sox9-EGFP (Sox9-EGFP High). We hypothesized that Sox9-EGFP Low ISCs would expand after radiation, exhibit enhanced proliferative capacities, and adopt a distinct gene expression profile associated with rapid proliferation. Sox9-EGFP mice were given 14 Gy abdominal radiation and studied between days 3 and 9 postradiation. Radiation-induced changes in number, growth, and transcriptome of the different Sox9-EGFP cell populations were determined by histology, flow cytometry, in vitro culture assays, and microarray. Microarray confirmed that nonirradiated Sox9-EGFP Low cells are enriched for Lgr5 mRNA and mRNAs enriched in Lgr5-ISCs and identified additional putative ISC markers. Sox9-EGFP High cells were enriched for EEC markers, as well as Bmi1 and Hopx, which are putative markers of quiescent ISCs. Irradiation caused complete crypt loss, followed by expansion and hyperproliferation of Sox9-EGFP Low cells. From nonirradiated intestine, only Sox9-EGFP Low cells exhibited ISC characteristics of forming organoids in culture, whereas during regeneration both Sox9-EGFP Low and High cells formed organoids. Microarray demonstrated that regenerating Sox9-EGFP High cells exhibited transcriptomic changes linked to p53-signaling and ISC-like functions including DNA repair and reduced oxidative metabolism. These findings support a model in which Sox9-EGFP Low cells represent active ISCs, Sox9-EGFP High cells contain radiation-activatable cells with ISC characteristics, and both participate in crypt regeneration. PMID:22361729

  18. Labeling and Imaging Mesenchymal Stem Cells with Quantum Dots

    EPA Science Inventory

    Mesenchymal stem cells (MSCs) are multipotent cells with the potential to differentiate into bone, cartilage, adipose and muscle cells. Adult derived MSCs are being actively investigated because of their potential to be utilized for therapeutic cell-based transplantation. Methods...

  19. Cellular and transcriptomic analysis of human mesenchymal stem cell response to plasma-activated hydroxyapatite coating.

    PubMed

    Tan, Fei; O'Neill, Feidhlim; Naciri, Mariam; Dowling, Denis; Al-Rubeai, Mohamed

    2012-04-01

    Atmospheric pressure plasma has recently emerged as a technique with a promising future in the medical field. In this work we used the technique as a post-deposition modification process as a means to activate hydroxyapatite (HA) coatings. Contact angle goniometry, optical profilometry, scanning electron microscopy morphology imaging and X-ray photoelectron spectroscopy analysis demonstrate that surface wettability is improved after treatment, without inducing any concomitant damage to the coating. The protein adsorption pattern has been found to be preferable for MSC, and this may result in greater cell attachment and adhesion to plasma-activated HA than to untreated samples. Cell cycle distribution analysis using flow cytometry reveals a faster transition from G(1) to S phase, thus leading to a faster cell proliferation rate on plasma-activated HA. This indicates that the improvement in surface wettability independently enhances cell attachment and cell proliferation, which is possibly mediated by FAK phosphorylation. Pathway-specific polymerase chain reaction arrays revealed that wettability has a substantial influence on gene expression during osteogenic differentiation of human MSC. Plasma-activated HA tends to enhance this process by systemically deregulating multiple genes. In addition, the majority of these deregulated genes had been appropriately translated, as confirmed by ELISA protein quantification. Lastly, alizarin red staining showed that plasma-activated HA is capable of improving mineralization for up to 3 weeks of in vitro culture. It was concluded from this study that atmospheric pressure plasma is a potent tool for modifying the biological function of a material without causing thermal damage, such that adhesion molecules and drugs might be deposited on the original coating to improve performance.

  20. Advances in stem cell therapy.

    PubMed

    Pérez López, Silvia; Otero Hernández, Jesús

    2012-01-01

    Since the beginning of stem cell biology, considerable effort has been focused in the translation of scientific insights into new therapies. Cell-based assays represent a new strategy for organ and tissue repair in several pathologies. Moreover, alternative treatment strategies are urgently needed due to donor organ shortage that costs many lives every year and results in lifelong immunosuppression. At the moment, only the use of hematopoietic stem cells is considered as the standard for the treatment of malignant and genetic bone marrow disorders, being all other stem cell applications highly experimental. The present chapter tries to summarize some ongoing approaches of stem cell regenerative medicine and also introduces recent findings from published studies and trials conducted in various tissues such as skeletal muscle, liver and lung.

  1. Bone marrow mesenchymal stem cells suppressing activation of allogeneic cytokine-induced killer/natural killer cells either by direct or indirect interaction.

    PubMed

    Li, Yang; Qu, Yu H; Wu, Yan F; Liu, Ling; Lin, Xiang H; Huang, Ke; Wei, Jing

    2015-04-01

    Bone marrow mesenchymal stem cells (MSC) were recently found to be associated with some special immunological characteristics, the immunoregulatory effect of MSC was dose-dependent. Low amount of MSC was associated with mild immunosuppression or even immune activation, while the high amount of that was associated with significant immunosuppressive effect. In this study, by using a transwell system, we explored the effect of MSC on the cell cycle, apoptosis rate and the expression of CD69, an activation marker, on the allogeneic cord blood derived cytokine-induced killer(CIK)/natural killer(NK) cells. The results showed that either by transwell or mixed cell-cell co-culture, the MSC can effect CIK/NK cells on the cell cycle, such as arrested in the G0/G1 phase, diminished the ratio of cells in S, G2/M phase, and increased the apoptosis of them. MSC can also depress the expression of CD69 on these killer cells, as well as increased the ratio of CD4(+) CD25(+) CD127(low) T regulatory (Treg) cells in the CIK/NK cell culture system. We draw conclusions that either by transwell or mixed co-culture, the MSC can suppress activation of allogeneic CB-CIK/NK cells in a dose-dependent manner.

  2. Stem cell platforms for regenerative medicine.

    PubMed

    Nelson, Timothy J; Behfar, Atta; Yamada, Satsuki; Martinez-Fernandez, Almudena; Terzic, Andre

    2009-06-01

    The pandemic of chronic degenerative diseases associated with aging demographics mandates development of effective approaches for tissue repair. As diverse stem cells directly contribute to innate healing, the capacity for de novo tissue reconstruction harbors a promising role for regenerative medicine. Indeed, a spectrum of natural stem cell sources ranging from embryonic to adult progenitors has been recently identified with unique characteristics for regeneration. The accessibility and applicability of the regenerative armamentarium has been further expanded with stem cells engineered by nuclear reprogramming. Through strategies of replacement to implant functional tissues, regeneration to transplant progenitor cells or rejuvenation to activate endogenous self-repair mechanisms, the overarching goal of regenerative medicine is to translate stem cell platforms into practice and achieve cures for diseases limited to palliative interventions. Harnessing the full potential of each platform will optimize matching stem cell-based biologics with the disease-specific niche environment of individual patients to maximize the quality of long-term management, while minimizing the needs for adjunctive therapy. Emerging discovery science with feedback from clinical translation is therefore poised to transform medicine offering safe and effective stem cell biotherapeutics to enable personalized solutions for incurable diseases. PMID:19779576

  3. A time frame permissive for Protein Kinase D2 activity to direct angiogenesis in mouse embryonic stem cells.

    PubMed

    Müller, Martin; Schröer, Jana; Azoitei, Ninel; Eiseler, Tim; Bergmann, Wendy; Köhntop, Ralf; Lin, Qiong; Costa, Ivan G; Zenke, Martin; Genze, Felicitas; Weidgang, Clair; Seufferlein, Thomas; Liebau, Stefan; Kleger, Alexander

    2015-01-01

    The protein kinase D isoenzymes PKD1/2/3 are prominent downstream targets of PKCs (Protein Kinase Cs) and phospholipase D in various biological systems. Recently, we identified PKD isoforms as novel mediators of tumour cell-endothelial cell communication, tumour cell motility and metastasis. Although PKD isoforms have been implicated in physiological/tumour angiogenesis, a role of PKDs during embryonic development, vasculogenesis and angiogenesis still remains elusive. We investigated the role of PKDs in germ layer segregation and subsequent vasculogenesis and angiogenesis using mouse embryonic stem cells (ESCs). We show that mouse ESCs predominantly express PKD2 followed by PKD3 while PKD1 displays negligible levels. Furthermore, we demonstrate that PKD2 is specifically phosphorylated/activated at the time of germ layer segregation. Time-restricted PKD2-activation limits mesendoderm formation and subsequent cardiovasculogenesis during early differentiation while leading to branching angiogenesis during late differentiation. In line, PKD2 loss-of-function analyses showed induction of mesendodermal differentiation in expense of the neuroectodermal germ layer. Our in vivo findings demonstrate that embryoid bodies transplanted on chicken chorioallantoic membrane induced an angiogenic response indicating that timed overexpression of PKD2 from day 4 onwards leads to augmented angiogenesis in differentiating ESCs. Taken together, our results describe novel and time-dependent facets of PKD2 during early cell fate determination. PMID:26148697

  4. A time frame permissive for Protein Kinase D2 activity to direct angiogenesis in mouse embryonic stem cells

    PubMed Central

    Müller, Martin; Schröer, Jana; Azoitei, Ninel; Eiseler, Tim; Bergmann, Wendy; Köhntop, Ralf; Lin, Qiong; Costa, Ivan G; Zenke, Martin; Genze, Felicitas; Weidgang, Clair; Seufferlein, Thomas; Liebau, Stefan; Kleger, Alexander

    2015-01-01

    The protein kinase D isoenzymes PKD1/2/3 are prominent downstream targets of PKCs (Protein Kinase Cs) and phospholipase D in various biological systems. Recently, we identified PKD isoforms as novel mediators of tumour cell-endothelial cell communication, tumour cell motility and metastasis. Although PKD isoforms have been implicated in physiological/tumour angiogenesis, a role of PKDs during embryonic development, vasculogenesis and angiogenesis still remains elusive. We investigated the role of PKDs in germ layer segregation and subsequent vasculogenesis and angiogenesis using mouse embryonic stem cells (ESCs). We show that mouse ESCs predominantly express PKD2 followed by PKD3 while PKD1 displays negligible levels. Furthermore, we demonstrate that PKD2 is specifically phosphorylated/activated at the time of germ layer segregation. Time-restricted PKD2-activation limits mesendoderm formation and subsequent cardiovasculogenesis during early differentiation while leading to branching angiogenesis during late differentiation. In line, PKD2 loss-of-function analyses showed induction of mesendodermal differentiation in expense of the neuroectodermal germ layer. Our in vivo findings demonstrate that embryoid bodies transplanted on chicken chorioallantoic membrane induced an angiogenic response indicating that timed overexpression of PKD2 from day 4 onwards leads to augmented angiogenesis in differentiating ESCs. Taken together, our results describe novel and time-dependent facets of PKD2 during early cell fate determination. PMID:26148697

  5. Therapeutic activities of engrafted neural stem/precursor cells are not dormant in the chronically injured spinal cord.

    PubMed

    Kumamaru, Hiromi; Saiwai, Hirokazu; Kubota, Kensuke; Kobayakawa, Kazu; Yokota, Kazuya; Ohkawa, Yasuyuki; Shiba, Keiichiro; Iwamoto, Yukihide; Okada, Seiji

    2013-08-01

    The transplantation of neural stem/precursor cells (NSPCs) is a promising therapeutic strategy for many neurodegenerative disorders including spinal cord injury (SCI) because it provides for neural replacement or trophic support. This strategy is now being extended to the treatment of chronic SCI patients. However, understanding of biological properties of chronically transplanted NSPCs and their surrounding environments is limited. Here, we performed temporal analysis of injured spinal cords and demonstrated their multiphasic cellular and molecular responses. In particular, chronically injured spinal cords were growth factor-enriched environments, whereas acutely injured spinal cords were enriched by neurotrophic and inflammatory factors. To determine how these environmental differences affect engrafted cells, NSPCs transplanted into acutely, subacutely, and chronically injured spinal cords were selectively isolated by flow cytometry, and their whole transcriptomes were compared by RNA sequencing. This analysis revealed that NSPCs produced many regenerative/neurotrophic molecules irrespective of transplantation timing, and these activities were prominent in chronically transplanted NSPCs. Furthermore, chronically injured spinal cords permitted engrafted NSPCs to differentiate into neurons/oligodendrocytes and provided more neurogenic environment for NSPCs than other environments. Despite these results demonstrate that transplanted NSPCs have adequate capacity in generating neurons/oligodendrocytes and producing therapeutic molecules in chronic SCI microenvironments, they did not improve locomotor function. Our results indicate that failure in chronic transplantation is not due to the lack of therapeutic activities of engrafted NSPCs but the refractory state of chronically injured spinal cords. Environmental modulation, rather modification of transplanting cells, will be significant for successful translation of stem cell-based therapies into chronic SCI patients.

  6. Activated human mesenchymal stem/stromal cells suppress metastatic features of MDA-MB-231 cells by secreting IFN-β.

    PubMed

    Yoon, N; Park, M S; Shigemoto, T; Peltier, G; Lee, R H

    2016-01-01

    Our recent study showed that human mesenchymal stem/stromal cells (hMSCs) are activated to express tumor necrosis factor (TNF)-α-related apoptosis-inducing ligand (TRAIL) by exposure to TNF-α and these activated hMSCs effectively induce apoptosis in triple-negative breast cancer MDA-MB-231 (MDA) cells in vitro and in vivo. Here, we further demonstrated that activated hMSCs not only induced apoptosis of MDA cells but also reduced metastatic features in MDA cells. These activated hMSC-exposed MDA cells showed reduced tumorigenicity and suppressed formation of lung metastasis when implanted in the mammary fat pad. Surprisingly, the activated hMSC-exposed MDA cells increased TRAIL expression, resulting in apoptosis in MDA cells. Interestingly, upregulation of TRAIL in MDA cells was mediated by interferon-beta (IFN-β) secreted from activated hMSCs. Furthermore, IFN-β in activated hMSCs was induced by RNA and DNA released from apoptotic MDA cells in absent in melanoma 2 (AIM2) and IFN induced with helicase C domain 1 (IFIH1)-dependent manners. These observations were only seen in the TRAIL-sensitive breast cancer cell lines but not in the TRAIL-resistant breast cancer cell lines. Consistent with these results, Kaplan-Meier survival analysis also showed that lack of innate sensors detecting DNA or RNA is strongly associated with poor survival in estrogen receptor-negative breast cancer patients. In addition, cancer-associated fibroblasts (CAF) isolated from a breast cancer patient were also able to express TRAIL and IFN-β upon DNA and RNA stimulation. Therefore, our results suggest that the crosstalk between TRAIL-sensitive cancer cells and stromal cells creates a tumor-suppressive microenvironment and further provide a novel therapeutic approach to target stromal cells within cancer microenvironment for TRAIL sensitive cancer treatment. PMID:27077807

  7. Activated human mesenchymal stem/stromal cells suppress metastatic features of MDA-MB-231 cells by secreting IFN-β

    PubMed Central

    Yoon, N; Park, M S; Shigemoto, T; Peltier, G; Lee, R H

    2016-01-01

    Our recent study showed that human mesenchymal stem/stromal cells (hMSCs) are activated to express tumor necrosis factor (TNF)-α-related apoptosis-inducing ligand (TRAIL) by exposure to TNF-α and these activated hMSCs effectively induce apoptosis in triple-negative breast cancer MDA-MB-231 (MDA) cells in vitro and in vivo. Here, we further demonstrated that activated hMSCs not only induced apoptosis of MDA cells but also reduced metastatic features in MDA cells. These activated hMSC-exposed MDA cells showed reduced tumorigenicity and suppressed formation of lung metastasis when implanted in the mammary fat pad. Surprisingly, the activated hMSC-exposed MDA cells increased TRAIL expression, resulting in apoptosis in MDA cells. Interestingly, upregulation of TRAIL in MDA cells was mediated by interferon-beta (IFN-β) secreted from activated hMSCs. Furthermore, IFN-β in activated hMSCs was induced by RNA and DNA released from apoptotic MDA cells in absent in melanoma 2 (AIM2) and IFN induced with helicase C domain 1 (IFIH1)-dependent manners. These observations were only seen in the TRAIL-sensitive breast cancer cell lines but not in the TRAIL-resistant breast cancer cell lines. Consistent with these results, Kaplan–Meier survival analysis also showed that lack of innate sensors detecting DNA or RNA is strongly associated with poor survival in estrogen receptor-negative breast cancer patients. In addition, cancer-associated fibroblasts (CAF) isolated from a breast cancer patient were also able to express TRAIL and IFN-β upon DNA and RNA stimulation. Therefore, our results suggest that the crosstalk between TRAIL-sensitive cancer cells and stromal cells creates a tumor-suppressive microenvironment and further provide a novel therapeutic approach to target stromal cells within cancer microenvironment for TRAIL sensitive cancer treatment. PMID:27077807

  8. SHP2 phosphatase promotes mast cell chemotaxis toward stem cell factor via enhancing activation of the Lyn/Vav/Rac signaling axis.

    PubMed

    Sharma, Namit; Everingham, Stephanie; Ramdas, Baskar; Kapur, Reuben; Craig, Andrew W B

    2014-05-15

    SHP2 protein-tyrosine phosphatase (encoded by Ptpn11) positively regulates KIT (CD117) signaling in mast cells and is required for mast cell survival and homeostasis in mice. In this study, we uncover a role of SHP2 in promoting chemotaxis of mast cells toward stem cell factor (SCF), the ligand for KIT receptor. Using an inducible SHP2 knockout (KO) bone marrow-derived mast cell (BMMC) model, we observed defects in SCF-induced cell spreading, polarization, and chemotaxis. To address the mechanisms involved, we tested whether SHP2 promotes activation of Lyn kinase that was previously shown to promote mast cell chemotaxis. In SHP2 KO BMMCs, SCF-induced phosphorylation of the inhibitory C-terminal residue (pY507) was elevated compared with control cells, and phosphorylation of activation loop (pY396) was diminished. Because Lyn also was detected by substrate trapping assays, these results are consistent with SHP2 activating Lyn directly by dephosphorylation of pY507. Further analyses revealed a SHP2- and Lyn-dependent pathway leading to phosphorylation of Vav1, Rac activation, and F-actin polymerization in SCF-treated BMMCs. Treatment of BMMCs with a SHP2 inhibitor also led to impaired chemotaxis, consistent with SHP2 promoting SCF-induced chemotaxis of mast cells via a phosphatase-dependent mechanism. Thus, SHP2 inhibitors may be useful to limit SCF/KIT-induced mast cell recruitment to inflamed tissues or the tumor microenvironment.

  9. Novel Function of Sprouty4 as a Regulator of Stemness and Differentiation of Embryonic Stem Cells

    PubMed Central

    Lee, Jae-Young; Park, Sunghyun; Kim, Kwang-Soo; Ko, Jeong-Jae; Lee, Soohong; Kim, Keun Pil; Park, Kyung-Soon

    2016-01-01

    Sprouty (Spry) genes encode inhibitors of the receptor tyrosine kinase signaling cascade, which plays important roles in stem cells. However, the role of Spry4 in the stemness of embryonic stem cells has not been fully elucidated. Here, we used mouse embryonic stem cells (mESCs) as a model system to investigate the role of Spry4 in the stem cells. Suppression of Spry4 expression results in the decreases of cell proliferation, EB formation and stemness marker expression, suggesting that Spry4 activity is associated with stemness of mESCs. Teratoma assay showed that the cartilage maturation was facilitated in Spry4 knocked down mESCs. Our results suggest that Spry4 is an important regulator of the stemness and differentiation of mESCs. PMID:27660833

  10. Novel Function of Sprouty4 as a Regulator of Stemness and Differentiation of Embryonic Stem Cells.

    PubMed

    Lee, Jae-Young; Park, Sunghyun; Kim, Kwang-Soo; Ko, Jeong-Jae; Lee, Soohong; Kim, Keun Pil; Park, Kyung-Soon

    2016-06-01

    Sprouty (Spry) genes encode inhibitors of the receptor tyrosine kinase signaling cascade, which plays important roles in stem cells. However, the role of Spry4 in the stemness of embryonic stem cells has not been fully elucidated. Here, we used mouse embryonic stem cells (mESCs) as a model system to investigate the role of Spry4 in the stem cells. Suppression of Spry4 expression results in the decreases of cell proliferation, EB formation and stemness marker expression, suggesting that Spry4 activity is associated with stemness of mESCs. Teratoma assay showed that the cartilage maturation was facilitated in Spry4 knocked down mESCs. Our results suggest that Spry4 is an important regulator of the stemness and differentiation of mESCs. PMID:27660833

  11. College Students' Conceptions of Stem Cells, Stem Cell Research, and Cloning

    NASA Astrophysics Data System (ADS)

    Concannon, James P.; Siegel, Marcelle A.; Halverson, Kristy; Freyermuth, Sharyn

    2010-04-01

    In this study, we examined 96 undergraduate non-science majors' conceptions of stem cells, stem cell research, and cloning. This study was performed at a large, Midwest, research extensive university. Participants in the study were asked to answer 23 questions relating to stem cells, stem cell research, and cloning in an on-line assessment before and after instruction. Two goals of the instruction were to: (1) help students construct accurate scientific ideas, and (2) enhance their reasoning about socioscientific issues. The course structure included interactive lectures, case discussions, hands-on activities, and independent projects. Overall, students' understandings of stem cells, stem cell research, and cloning increased from pre-test to post-test. For example, on the post-test, students gained knowledge concerning the age of an organism related to the type of stem cell it possesses. However, we found that some incorrect ideas that were evident on the pre-test persisted after instruction. For example, before and after instruction several students maintained the idea that stem cells can currently be used to produce organs.

  12. Connexin 50 Expression in Ependymal Stem Progenitor Cells after Spinal Cord Injury Activation.

    PubMed

    Rodriguez-Jimenez, Francisco Javier; Alastrue-Agudo, Ana; Stojkovic, Miodrag; Erceg, Slaven; Moreno-Manzano, Victoria

    2015-01-01

    Ion channels included in the family of Connexins (Cx) help to control cell proliferation and differentiation of neuronal progenitors. Here we explored the role of Connexin 50 (Cx50) in cell fate modulation of adult spinal cord derived neural precursors located in the ependymal canal (epSPC). epSPC from non-injured animals showed high expression levels of Cx50 compared to epSPC from animals with spinal cord injury (SCI) (epSPCi). When epSPC or epSPCi were induced to spontaneously differentiate in vitro we found that Cx50 favors glial cell fate, since higher expression levels, endogenous or by over-expression of Cx50, augmented the expression of the astrocyte marker GFAP and impaired the neuronal marker Tuj1. Cx50 was found in both the cytoplasm and nucleus of glial cells, astrocytes and oligodendrocyte-derived cells. Similar expression patterns were found in primary cultures of mature astrocytes. In addition, opposite expression profile for nuclear Cx50 was observed when epSPC and activated epSPCi were conducted to differentiate into mature oligodendrocytes, suggesting a different role for this ion channel in spinal cord beyond cell-to-cell communication. In vivo detection of Cx50 by immunohistochemistry showed a defined location in gray matter in non-injured tissues and at the epicenter of the injury after SCI. epSPCi transplantation, which accelerates locomotion regeneration by a neuroprotective effect after acute SCI is associated with a lower signal of Cx50 within the injured area, suggesting a minor or detrimental contribution of this ion channel in spinal cord regeneration by activated epSPCi. PMID:26561800

  13. Cancer Stem Cells Protect Non-Stem Cells From Anoikis: Bystander Effects.

    PubMed

    Kim, Seog-Young; Hong, Se-Hoon; Basse, Per H; Wu, Chuanyue; Bartlett, David L; Kwon, Yong Tae; Lee, Yong J

    2016-10-01

    Cancer stem cells (CSCs) are capable of initiation and metastasis of tumors. Therefore, understanding the biology of CSCs and the interaction between CSCs and their counterpart non-stem cells is crucial for developing a novel cancer therapy. We used CSC-like and non-stem breast cancer MDA-MB-231 and MDA-MB-453 cells to investigate mammosphere formation. We investigated the role of the epithelial cadherin (E-cadherin)-extracellular signal-regulated kinase (Erk) axis in anoikis. Data from E-cadherin small hairpin RNA assay and mitogen-activated protein kinase kinase (MEK) inhibitor study show that activation of Erk, but not modulation of E-cadherin level, may play an important role in anoikis resistance. Next, the two cell subtypes were mixed and the interaction between them during mammosphere culture and xenograft tumor formation was investigated. Unlike CSC-like cells, increased secretion of interleukin-6 (IL-6) and growth-related oncogene (Gro) chemokines was detected during mammosphere culture in non-stem cells. Similar results were observed in mixed cells. Interestingly, CSC-like cells protected non-stem cells from anoikis and promoted tumor growth. Our results suggest bystander effects between CSC-like cells and non-stem cells. J. Cell. Biochem. 117: 2289-2301, 2016. © 2016 Wiley Periodicals, Inc. PMID:26918647

  14. MHC-compatible bone marrow stromal/stem cells trigger fibrosis by activating host T cells in a scleroderma mouse model.

    PubMed

    Ogawa, Yoko; Morikawa, Satoru; Okano, Hideyuki; Mabuchi, Yo; Suzuki, Sadafumi; Yaguchi, Tomonori; Sato, Yukio; Mukai, Shin; Yaguchi, Saori; Inaba, Takaaki; Okamoto, Shinichiro; Kawakami, Yutaka; Tsubota, Kazuo; Matsuzaki, Yumi; Shimmura, Shigeto

    2016-01-26

    Fibrosis of organs is observed in systemic autoimmune disease. Using a scleroderma mouse, we show that transplantation of MHC compatible, minor antigen mismatched bone marrow stromal/stem cells (BMSCs) play a role in the pathogenesis of fibrosis. Removal of donor BMSCs rescued mice from disease. Freshly isolated PDGFRα(+) Sca-1(+) BMSCs expressed MHC class II following transplantation and activated host T cells. A decrease in FOXP3(+) CD25(+) Treg population was observed. T cells proliferated and secreted IL-6 when stimulated with mismatched BMSCs in vitro. Donor T cells were not involved in fibrosis because transplanting T cell-deficient RAG2 knock out mice bone marrow still caused disease. Once initially triggered by mismatched BMSCs, the autoimmune phenotype was not donor BMSC dependent as the phenotype was observed after effector T cells were adoptively transferred into naïve syngeneic mice. Our data suggest that minor antigen mismatched BMSCs trigger systemic fibrosis in this autoimmune scleroderma model.

  15. Vascular Potential of Human Pluripotent Stem Cells

    PubMed Central

    Iacobas, Ionela; Vats, Archana; Hirschi, Karen K.

    2010-01-01

    Cardiovascular disease is the number one cause of death and disability in the US. Understanding the biological activity of stem and progenitor cells, and their ability to contribute to the repair, regeneration and remodeling of the heart and blood vessels affected by pathologic processes is an essential part of the paradigm in enabling us to achieve a reduction in related deaths. Both human embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are promising sources of cells for clinical cardiovascular therapies. Additional in vitro studies are needed, however, to understand their relative phenotypes and molecular regulation toward cardiovascular cell fates. Further studies in translational animal models are also needed to gain insights into the potential and function of both human ES- and iPS-derived cardiovascular cells, and enable translation from experimental and pre-clinical studies to human trials. PMID:20453170

  16. Intestinal Stem Cells: Got Calcium?

    PubMed

    Nászai, Máté; Cordero, Julia B

    2016-02-01

    Calcium ions are well-known intracellular signalling molecules. A new study identifies local cytoplasmic calcium as a central integrator of metabolic and proliferative signals in Drosophila intestinal stem cells. PMID:26859268

  17. Mammary Stem Cells and Tumor-Initiating Cells Are More Resistant to Apoptosis and Exhibit Increased DNA Repair Activity in Response to DNA Damage

    PubMed Central

    Chang, Chi-Hsuan; Zhang, Mei; Rajapakshe, Kimal; Coarfa, Cristian; Edwards, Dean; Huang, Shixia; Rosen, Jeffrey M.

    2015-01-01

    Summary Adult stem cells and tumor-initiating cells (TICs) often employ different mechanisms of DNA damage response (DDR) as compared to other tissue cell types. However, little is known about how mammary stem cells (MaSCs) and mammary TICs respond to DNA damage. Using the mouse mammary gland and syngeneic p53-null tumors as models, we investigated the molecular and physiological consequences of DNA damage in wild-type MaSCs, p53-null MaSCs, and p53-null TICs. We showed that wild-type MaSCs and basal cells are more resistant to apoptosis and exhibit increased non-homologous end joining (NHEJ) activity. Loss of p53 in mammary epithelium affected both cell-cycle regulation and DNA repair efficiency. In p53-null tumors, we showed that TICs are more resistant to ionizing radiation (IR) due to decreased apoptosis, elevated NHEJ activity, and more-rapid DNA repair. These results have important implications for understanding DDR mechanisms involved in both tumorigenesis and therapy resistance. PMID:26300228

  18. Human adipose tissue possesses a unique population of pluripotent stem cells with nontumorigenic and low telomerase activities: potential implications in regenerative medicine.

    PubMed

    Ogura, Fumitaka; Wakao, Shohei; Kuroda, Yasumasa; Tsuchiyama, Kenichiro; Bagheri, Mozhdeh; Heneidi, Saleh; Chazenbalk, Gregorio; Aiba, Setsuya; Dezawa, Mari

    2014-04-01

    In this study, we demonstrate that a small population of pluripotent stem cells, termed adipose multilineage-differentiating stress-enduring (adipose-Muse) cells, exist in adult human adipose tissue and adipose-derived mesenchymal stem cells (adipose-MSCs). They can be identified as cells positive for both MSC markers (CD105 and CD90) and human pluripotent st