Modeling human infertility with pluripotent stem cells

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Di Chen

2017-05-01

Full Text Available Human fertility is dependent upon the correct establishment and differentiation of the germline. This is because no other cell type in the body is capable of passing a genome and epigenome from parent to child. Terminally differentiated germline cells in the adult testis and ovary are called gametes. However, the initial specification of germline cells occurs in the embryo around the time of gastrulation. Most of our knowledge regarding the cell and molecular events that govern human germline specification involves extrapolating scientific principles from model organisms, most notably the mouse. However, recent work using next generation sequencing, gene editing and differentiation of germline cells from pluripotent stem cells has revealed that the core molecular mechanisms that regulate human germline development are different from rodents. Here, we will discuss the major molecular pathways required for human germline differentiation and how pluripotent stem cells have revolutionized our ability to study the earliest steps in human embryonic lineage specification in order to understand human fertility.

Germline competence of mouse ES and iPS cell lines: Chimera technologies and genetic background.

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Carstea, Ana Claudia; Pirity, Melinda K; Dinnyes, Andras

2009-12-31

In mice, gene targeting by homologous recombination continues to play an essential role in the understanding of functional genomics. This strategy allows precise location of the site of transgene integration and is most commonly used to ablate gene expression ("knock-out"), or to introduce mutant or modified alleles at the locus of interest ("knock-in"). The efficacy of producing live, transgenic mice challenges our understanding of this complex process, and of the factors which influence germline competence of embryonic stem cell lines. Increasingly, evidence indicates that culture conditions and in vitro manipulation can affect the germline-competence of Embryonic Stem cell (ES cell) lines by accumulation of chromosome abnormalities and/or epigenetic alterations of the ES cell genome. The effectiveness of ES cell derivation is greatly strain-dependent and it may also influence the germline transmission capability. Recent technical improvements in the production of germline chimeras have been focused on means of generating ES cells lines with a higher germline potential. There are a number of options for generating chimeras from ES cells (ES chimera mice); however, each method has its advantages and disadvantages. Recent developments in induced pluripotent stem (iPS) cell technology have opened new avenues for generation of animals from genetically modified somatic cells by means of chimera technologies. The aim of this review is to give a brief account of how the factors mentioned above are influencing the germline transmission capacity and the developmental potential of mouse pluripotent stem cell lines. The most recent methods for generating specifically ES and iPS chimera mice, including the advantages and disadvantages of each method are also discussed.

C. elegans nucleostemin is required for larval growth and germline stem cell division.

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Michelle M Kudron

2008-08-01

Full Text Available The nucleolus has shown to be integral for many processes related to cell growth and proliferation. Stem cells in particular are likely to depend upon nucleolus-based processes to remain in a proliferative state. A highly conserved nucleolar factor named nucleostemin is proposed to be a critical link between nucleolar function and stem-cell-specific processes. Currently, it is unclear whether nucleostemin modulates proliferation by affecting ribosome biogenesis or by another nucleolus-based activity that is specific to stem cells and/or highly proliferating cells. Here, we investigate nucleostemin (nst-1 in the nematode C. elegans, which enables us to examine nst-1 function during both proliferation and differentiation in vivo. Like mammalian nucleostemin, the NST-1 protein is localized to the nucleolus and the nucleoplasm; however, its expression is found in both differentiated and proliferating cells. Global loss of C. elegans nucleostemin (nst-1 leads to a larval arrest phenotype due to a growth defect in the soma, while loss of nst-1 specifically in the germ line causes germline stem cells to undergo a cell cycle arrest. nst-1 mutants exhibit reduced levels of rRNAs, suggesting defects in ribosome biogenesis. However, NST-1 is generally not present in regions of the nucleolus where rRNA transcription and processing occurs, so this reduction is likely secondary to a different defect in ribosome biogenesis. Transgenic studies indicate that NST-1 requires its N-terminal domain for stable expression and both its G1 GTPase and intermediate domains for proper germ line function. Our data support a role for C. elegans nucleostemin in cell growth and proliferation by promoting ribosome biogenesis.

Notch signaling mediates the age-associated decrease in adhesion of germline stem cells to the niche.

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Chen-Yuan Tseng

2014-12-01

Full Text Available Stem cells have an innate ability to occupy their stem cell niche, which in turn, is optimized to house stem cells. Organ aging is associated with reduced stem cell occupancy in the niche, but the mechanisms involved are poorly understood. Here, we report that Notch signaling is increased with age in Drosophila female germline stem cells (GSCs, and this results in their removal from the niche. Clonal analysis revealed that GSCs with low levels of Notch signaling exhibit increased adhesiveness to the niche, thereby out-competing their neighbors with higher levels of Notch; adhesiveness is altered through regulation of E-cadherin expression. Experimental enhancement of Notch signaling in GSCs hastens their age-dependent loss from the niche, and such loss is at least partially mediated by Sex lethal. However, disruption of Notch signaling in GSCs does not delay GSC loss during aging, and nor does it affect BMP signaling, which promotes self-renewal of GSCs. Finally, we show that in contrast to GSCs, Notch activation in the niche (which maintains niche integrity, and thus mediates GSC retention is reduced with age, indicating that Notch signaling regulates GSC niche occupancy both intrinsically and extrinsically. Our findings expose a novel role of Notch signaling in controlling GSC-niche adhesion in response to aging, and are also of relevance to metastatic cancer cells, in which Notch signaling suppresses cell adhesion.

miR-544 Regulates Dairy Goat Male Germline Stem Cell Self-Renewal via Targeting PLZF.

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Song, Wencong; Mu, Hailong; Wu, Jiang; Liao, Mingzhi; Zhu, Haijing; Zheng, Liming; He, Xin; Niu, Bowen; Zhai, Yuanxin; Bai, Chunling; Lei, Anmin; Li, Guangpeng; Hua, Jinlian

2015-10-01

The balance between the self-renewal and differentiation of male germline stem cells (mGSCs) is critical for the initiation and maintenance of mammalian spermatogenesis. The promyelocytic leukemia zinc finger (PLZF), a zinc finger protein, is a critical factor for maintaining the self-renewal of mGSCs, so, evaluation of the PLZF pathway in mGSCs may provide a deeper insight into mammalian spermatogenesis. miRNA was also an important regulating factor for the self-renewal and differentiation of mGSCs; however, there is currently no data indicating that which miRNA regulate the self-renewal and differentiation of mGSCs via PLZF. Here, we predicted the prospective miRNA targeting to PLZF using the online Bioinformatics database-Targetscan, and performed an analysis of the dual-luciferase recombinant vector, psiCHCEKTM-2-PLZF-3'UTR. miR-544 mimics (miR-544m), miR-544 inhibitors (miR-544i), Control (NC, scrambled oligonucleotides transfection), pPLZF-IRES2-EGFP or PLZF siRNA were transfected into mGSCs; the cells proliferation was evaluated by BRDU incorporation assay and flow cytometry, and the mGSC marker, GFRa1, PLZF, KIT, DAZL, and VASA expression were analyzed by RT-qPCR, immunofluorescence and Western blot. The results showed that miR-544 regulates dairy goat male germline stem cell self-renewal via targeting PLZF. Our study identifies a new regulatory pathway for PLZF and expands upon the PLZF regulatory network in mGSCs. © 2015 Wiley Periodicals, Inc.

Cell lineage analysis of the mammalian female germline.

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Yitzhak Reizel

Full Text Available Fundamental aspects of embryonic and post-natal development, including maintenance of the mammalian female germline, are largely unknown. Here we employ a retrospective, phylogenetic-based method for reconstructing cell lineage trees utilizing somatic mutations accumulated in microsatellites, to study female germline dynamics in mice. Reconstructed cell lineage trees can be used to estimate lineage relationships between different cell types, as well as cell depth (number of cell divisions since the zygote. We show that, in the reconstructed mouse cell lineage trees, oocytes form clusters that are separate from hematopoietic and mesenchymal stem cells, both in young and old mice, indicating that these populations belong to distinct lineages. Furthermore, while cumulus cells sampled from different ovarian follicles are distinctly clustered on the reconstructed trees, oocytes from the left and right ovaries are not, suggesting a mixing of their progenitor pools. We also observed an increase in oocyte depth with mouse age, which can be explained either by depth-guided selection of oocytes for ovulation or by post-natal renewal. Overall, our study sheds light on substantial novel aspects of female germline preservation and development.

ALIX and ESCRT-III coordinately control cytokinetic abscission during germline stem cell division in vivo.

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Åsmund H Eikenes

2015-01-01

Full Text Available Abscission is the final step of cytokinesis that involves the cleavage of the intercellular bridge connecting the two daughter cells. Recent studies have given novel insight into the spatiotemporal regulation and molecular mechanisms controlling abscission in cultured yeast and human cells. The mechanisms of abscission in living metazoan tissues are however not well understood. Here we show that ALIX and the ESCRT-III component Shrub are required for completion of abscission during Drosophila female germline stem cell (fGSC division. Loss of ALIX or Shrub function in fGSCs leads to delayed abscission and the consequent formation of stem cysts in which chains of daughter cells remain interconnected to the fGSC via midbody rings and fusome. We demonstrate that ALIX and Shrub interact and that they co-localize at midbody rings and midbodies during cytokinetic abscission in fGSCs. Mechanistically, we show that the direct interaction between ALIX and Shrub is required to ensure cytokinesis completion with normal kinetics in fGSCs. We conclude that ALIX and ESCRT-III coordinately control abscission in Drosophila fGSCs and that their complex formation is required for accurate abscission timing in GSCs in vivo.

Contribution of Mouse Embryonic Stem Cells and Induced Pluripotent Stem Cells to Chimeras through Injection and Coculture of Embryos

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Guo, Jitong; Wu, Baojiang; Li, Shuyu; Bao, Siqin; Zhao, Lixia; Hu, Shuxiang; Sun, Wei; Su, Jie; Dai, Yanfeng; Li, Xihe

2014-01-01

Blastocyst injection and morula aggregation are commonly used to evaluate stem cell pluripotency based on chimeric contribution of the stem cells. To assess the protocols for generating chimeras from stem cells, 8-cell mouse embryos were either injected or cocultured with mouse embryonic stem cells and induced pluripotent stem cells, respectively. Although a significantly higher chimera rate resulted from blastocyst injection, the highest germline contribution resulted from injection of 8-cel...

Structural polarity and dynamics of male germline stem cells in the milkweed bug (Oncopeltus fasciatus).

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Schmidt, Esther D; Dorn, August

2004-11-01

The male germline stem cells (GSCs) of the milkweed bug present an extraordinary structural polarity that is, to our knowledge, unequalled by any other type of stem cells. They consist of a perikaryon and numerous projections arising from the cell pole directed toward the apical cells, the proposed niche of the GSCs. The projections can traverse a considerable distance until their terminals touch the apical cells. From hatching until death, the GSC projections undergo conspicuous changes, the sequence of which has been deduced from observations of all developmental stages. Projection formation starts from lobular cell protrusions showing trabecular ingrowths of the cell membrane. Finger-like projections result from a process of growth and "carving out". The newly formed projections contain mostly only free ribosomes other than a few mitochondria. A stereotyped degradation process commences in the projection terminals: profiles of circular, often concentric, cisternae of rough endoplasmic reticulum appear and turn into myelin bodies, whereas mitochondria become more numerous. The cytoplasm vesiculates, lysosomal bodies appear, and mitochondria become swollen. At the same time, the projection terminals are segregated by transverse ingrowths of the cell membrane. Finally, autophagic vacuoles and myelin bodies fill the segregated terminals, which then rupture. Simultaneously, new projections seem to sprout from the perikaryon of the GSCs. These dynamics, which are not synchronized among the GSCs, indicate that a novel type of signal exchange and transduction between the stem cells and their niche is involved in the regulation of asymmetric versus symmetric division of GSCs.

When stem cells grow old: phenotypes and mechanisms of stem cell aging

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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. PMID:26732838

Localization of early germ cells in a stony coral, Euphyllia ancora: potential implications for a germline stem cell system in coral gametogenesis

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Shikina, Shinya; Chung, Yi-Jou; Wang, Hsiang-Ming; Chiu, Yi-Ling; Shao, Zih-Fang; Lee, Yan-Horn; Chang, Ching-Fong

2015-06-01

Most corals exhibit annual or multiple gametogenic cycles. Thus far, coral gametogenesis has been studied in many species and locations during the past three decades; however, currently, only a few papers exist that describe the origin of germ cells, such as germline stem cells (GSCs), which support the continuous production of gametes in every reproductive cycle. To address this issue, in this study, we focused on and identified piwi gene, which has been used as a marker of germline cells, including GSCs, in various metazoans, in a scleractinian coral, Euphyllia ancora. Reverse-transcription PCR and Western blotting analyses revealed that E. ancora piwi-like ( Eapiwi) is expressed in mesentery tissues where the sites of gametogenesis are located for both sexes. Immunohistochemistry with a specific antibody against Eapiwi revealed strong immunoreactivity in the spermatogonia in males and in the oogonia and early oocytes in females, demonstrating that Eapiwi could be used as an early germ cell marker in E. ancora. Subsequent immunohistochemical analyses regarding the spatial and temporal distribution patterns of early germ cells in mesentery tissues revealed that early germ cells were present throughout the year in the mesentery tissue we examined, regardless of the sexual reproductive cycle. In particular, small numbers of early germ cells were observed in specific sites of mesentery tissues with fully matured gonads in both sexes. These early germ cells were not released together with mature gametes during the spawning period and remained in the mesentery tissues. These results suggested that these early germ cells most likely serve as a reservoir of germline cells and that some of these cells would produce differentiated germ cells for the upcoming sexual reproduction period; hence, these cells would function as GSCs. Our data provide new information for understanding continuous gamete production in corals.

Aubergine Controls Germline Stem Cell Self-Renewal and Progeny Differentiation via Distinct Mechanisms.

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Ma, Xing; Zhu, Xiujuan; Han, Yingying; Story, Benjamin; Do, Trieu; Song, Xiaoqing; Wang, Su; Zhang, Ying; Blanchette, Marco; Gogol, Madelaine; Hall, Kate; Peak, Allison; Anoja, Perera; Xie, Ting

2017-04-24

Piwi family protein Aubergine (Aub) maintains genome integrity in late germ cells of the Drosophila ovary through Piwi-associated RNA-mediated repression of transposon activities. Although it is highly expressed in germline stem cells (GSCs) and early progeny, it remains unclear whether it plays any roles in early GSC lineage development. Here we report that Aub promotes GSC self-renewal and GSC progeny differentiation. RNA-iCLIP results show that Aub binds the mRNAs encoding self-renewal and differentiation factors in cultured GSCs. Aub controls GSC self-renewal by preventing DNA-damage-induced Chk2 activation and by translationally controlling the expression of self-renewal factors. It promotes GSC progeny differentiation by translationally controlling the expression of differentiation factors, including Bam. Therefore, this study reveals a function of Aub in GSCs and their progeny, which promotes translation of self-renewal and differentiation factors by directly binding to its target mRNAs and interacting with translational initiation factors. Copyright © 2017 Elsevier Inc. All rights reserved.

Germline stem cells and neo-oogenesis in the adult human ovary.

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Liu, Yifei; Wu, Chao; Lyu, Qifeng; Yang, Dongzi; Albertini, David F; Keefe, David L; Liu, Lin

2007-06-01

It remains unclear whether neo-oogenesis occurs in postnatal ovaries of mammals, based on studies in mice. We thought to test whether adult human ovaries contain germline stem cells (GSCs) and undergo neo-oogenesis. Rather than using genetic manipulation which is unethical in humans, we took the approach of analyzing the expression of meiotic marker genes and genes for germ cell proliferation, which are required for neo-oogenesis, in adult human ovaries covering an age range from 28 to 53 years old, compared to testis and fetal ovaries served as positive controls. We show that active meiosis, neo-oogenesis and GSCs are unlikely to exist in normal, adult, human ovaries. No early meiotic-specific or oogenesis-associated mRNAs for SPO11, PRDM9, SCP1, TERT and NOBOX were detectable in adult human ovaries using RT-PCR, compared to fetal ovary and adult testis controls. These findings are further corroborated by the absence of early meiocytes and proliferating germ cells in adult human ovarian cortex probed with markers for meiosis (SCP3), oogonium (OCT3/4, c-KIT), and cell cycle progression (Ki-67, PCNA), in contrast to fetal ovary controls. If postnatal oogenesis is confirmed in mice, then this species would represent an exception to the rule that neo-oogenesis does not occur in adults.

Propagation of human spermatogonial stem cells in vitro.

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Sadri-Ardekani, Hooman; Mizrak, Sefika C; van Daalen, Saskia K M; Korver, Cindy M; Roepers-Gajadien, Hermien L; Koruji, Morteza; Hovingh, Suzanne; de Reijke, Theo M; de la Rosette, Jean J M C H; van der Veen, Fulco; de Rooij, Dirk G; Repping, Sjoerd; van Pelt, Ans M M

2009-11-18

Young boys treated with high-dose chemotherapy are often confronted with infertility once they reach adulthood. Cryopreserving testicular tissue before chemotherapy and autotransplantation of spermatogonial stem cells at a later stage could theoretically allow for restoration of fertility. To establish in vitro propagation of human spermatogonial stem cells from small testicular biopsies to obtain an adequate number of cells for successful transplantation. Study performed from April 2007 to July 2009 using testis material donated by 6 adult men who underwent orchidectomy as part of prostate cancer treatment. Testicular cells were isolated and cultured in supplemented StemPro medium; germline stem cell clusters that arose were subcultured on human placental laminin-coated dishes in the same medium. Presence of spermatogonia was determined by reverse transcriptase polymerase chain reaction and immunofluorescence for spermatogonial markers. To test for the presence of functional spermatogonial stem cells in culture, xenotransplantation to testes of immunodeficient mice was performed, and migrated human spermatogonial stem cells after transplantation were detected by COT-1 fluorescence in situ hybridization. The number of colonized spermatogonial stem cells transplanted at early and later points during culture were counted to determine propagation. Propagation of spermatogonial stem cells over time. Testicular cells could be cultured and propagated up to 15 weeks. Germline stem cell clusters arose in the testicular cell cultures from all 6 men and could be subcultured and propagated up to 28 weeks. Expression of spermatogonial markers on both the RNA and protein level was maintained throughout the entire culture period. In 4 of 6 men, xenotransplantation to mice demonstrated the presence of functional spermatogonial stem cells, even after prolonged in vitro culture. Spermatogonial stem cell numbers increased 53-fold within 19 days in the testicular cell culture and

DAF-18/PTEN signals through AAK-1/AMPK to inhibit MPK-1/MAPK in feedback control of germline stem cell proliferation.

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Patrick Narbonne

2017-04-01

Full Text Available Under replete growth conditions, abundant nutrient uptake leads to the systemic activation of insulin/IGF-1 signalling (IIS and the promotion of stem cell growth/proliferation. Activated IIS can stimulate the ERK/MAPK pathway, the activation of which also supports optimal stem cell proliferation in various systems. Stem cell proliferation rates can further be locally refined to meet the resident tissue's need for differentiated progeny. We have recently shown that the accumulation of mature oocytes in the C. elegans germ line, through DAF-18/PTEN, inhibits adult germline stem cell (GSC proliferation, despite high systemic IIS activation. We show here that this feedback occurs through a novel cryptic signalling pathway that requires PAR-4/LKB1, AAK-1/AMPK and PAR-5/14-3-3 to inhibit the activity of MPK-1/MAPK, antagonize IIS, and inhibit both GSC proliferation and the production of additional oocytes. Interestingly, our results imply that DAF-18/PTEN, through PAR-4/LKB1, can activate AAK-1/AMPK in the absence of apparent energy stress. As all components are conserved, similar signalling cascades may regulate stem cell activities in other organisms and be widely implicated in cancer.

When stem cells grow old: phenotypes and mechanisms of stem cell aging.

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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. © 2016. Published by The Company of Biologists Ltd.

In Vitro Cytotoxicity of Nanoparticles in Mammalian Germline Stem Cells

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Braydich-Stolle, Laura; Hussain, Saber; Schlager, John J.; Hofmann, Marie-Claude

2005-01-01

Gametogenesis is a complex biological process that is particularly sensitive to environmental insults such as chemicals. Many chemicals have a negative impact on the germline, either by directly affecting the germ cells, or indirectly through their action on the somatic nursing cells. Ultimately, these effects can inhibit fertility, and they may have negative consequences for the development of the offspring. Recently, nanomaterials such as nanotubes, nanowires, fullerene derivatives (buckyba...

Promyelocytic leukaemia zinc finger maintains self-renewal of male germline stem cells (mGSCs) and its expression pattern in dairy goat testis.

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Song, W; Zhu, H; Li, M; Li, N; Wu, J; Mu, H; Yao, X; Han, W; Liu, W; Hua, J

2013-08-01

Previous studies have shown that promyelocytic leukaemia zinc finger (PLZF) is a spermatogonia-specific transcription factor in the testis, required to regulate self-renewal and maintenance of the spermatogonia stem cell. Up to now, expression and function of PLZF in the goat testis has not been known. The objectives of this study were to investigate PLZF expression pattern in the dairy goat and its effect on male goat germline stem cell (mGSC) self-renewal and differentiation. Testis development and expression patterns of PLZF in the dairy goat were analysed by haematoxylin and eosin staining, immunohistochemistry and reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, effects of PLZF overexpression on mGSC self-renewal and differentiation were evaluated by quantitative RT-PCR (QRT-PCR), immunofluorescence and BrdU incorporation assay. Promyelocytic leukaemia zinc finger was essential for dairy goat testis development and expression of several proliferation and pluripotency-associated proteins including OCT4, C-MYC were upregulated by PLZF overexpression. The study demonstrated that PLZF played a key role in maintaining self-renewal of mGSCs and its overexpression enhanced expression of proliferation-associated genes. Promyelocytic leukaemia zinc finger could function in the dairy goat as well as in other species in maintaining self-renewal of germline stem cells and this study provides a model to study the mechanism on self-renewal and differentiation of mGSCs in livestock. © 2013 John Wiley & Sons Ltd.

Piwi and potency: PIWI proteins in animal stem cells and regeneration.

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van Wolfswinkel, Josien C

2014-10-01

PIWI proteins are well known for their roles in the animal germline. They are essential for germline development and maintenance, and together with their binding partners, the piRNAs, they mediate transposon silencing. More recently, PIWI proteins have also been identified in somatic stem cells in diverse animals. The expression of PIWI proteins in these cells could be related to the ability of such cells to contribute to the germline. However, evaluation of stem cell systems across many different animal phyla suggests that PIWI proteins have an ancestral role in somatic stem cells, irrespective of their contribution to the germ cell lineage. Moreover, the data currently available reveal a possible correlation between the differentiation potential of a cell and its PIWI levels. © The Author 2014. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

p38 MAPK pathway is essential for self-renewal of mouse male germline stem cells (mGSCs).

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Niu, Zhiwei; Mu, Hailong; Zhu, Haijing; Wu, Jiang; Hua, Jinlian

2017-02-01

Male germline stem cells (mGSCs), also called spermatogonial stem cells (SSCs), constantly generate spermatozoa in male animals. A number of preliminary studies on mechanisms of mGSC self-renewal have previously been conducted, revealing that several factors are involved in this regulated process. The p38 MAPK pathway is widely conserved in multiple cell types in vivo, and plays an important role in cell proliferation, differentiation, inflammation and apoptosis. However, its role in self-renewal of mGSCs has not hitherto been determined. Here, the mouse mGSCs were cultured and their identity was verified by semi-RT-PCR, alkaline phosphatase (AP) staining and immunofluorescence staining. Then, the p38 MAPK pathway was blocked by p38 MAPK-specific inhibitor SB202190. mGSC self-renewal ability was then analysed by observation of morphology, cell number, cell growth analysis, TUNEL incorporation assay and cell cycle analysis. Results showed that mouse mGSC self-renewal ability was significantly inhibited by SB202190. This study showed for the first time that the p38 MAPK pathway plays a key role in maintaining self-renewal capacity of mouse mGSCs, which offers a new self-renewal pathway for these cells and contributes to overall knowledge of the mechanisms of mGSC self-renewal. © 2016 John Wiley & Sons Ltd.

Enrichment of Female Germline Stem Cells from Mouse Ovaries Using the Differential Adhesion Method

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Meng Wu

2018-04-01

Full Text Available Background/Aims: The isolation and establishment of female germline stem cells (FGSCs is controversial because of questions regarding the reliability and stability of the isolation method using antibody targeting mouse vasa homologue (MVH, and the molecular mechanism of FGSCs self-renewal remains unclear. Thus, there needs to be a simple and reliable method for sorting FGSCs to study them. Methods: We applied the differential adhesion method to enrich FGSCs (DA-FGSCs from mouse ovaries. Through four rounds of purification and 7-9 subsequent passages, DA-FGSC lines were established. In addition, we assessed the role of the phosphoinositide-3 kinase (PI3K-AKT pathway in regulating FGSC self-renewal. Results: The obtained DA-FGSCs spontaneously differentiated into oocyte-like cells in vitro and formed functional eggs in vivo that were fertilized and produced healthy offspring. AKT was rapidly phosphorylated when the proliferation rate of FGSCs increased after 10 passages, and the addition of a chemical PI3K inhibitor prevented FGSCs self-renewal. Furthermore, over-expression of AKT-induced proliferation and differentiation of FGSCs, c-Myc, Oct-4 and Gdf-9 levels were increased. Conclusions: The differential adhesion method provides a more feasible approach and is an easier procedure to establish FGSC lines than traditional methods. The AKT pathway plays an important role in regulation of the proliferation and maintenance of FGSCs. These findings could help promote stem cell studies and provide a better understanding of causes of ovarian infertility, thereby providing potential treatments for infertility.

Enrichment of Female Germline Stem Cells from Mouse Ovaries Using the Differential Adhesion Method.

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Wu, Meng; Xiong, Jiaqiang; Ma, Lingwei; Lu, Zhiyong; Qin, Xian; Luo, Aiyue; Zhang, Jinjin; Xie, Huan; Shen, Wei; Wang, Shixuan

2018-04-28

The isolation and establishment of female germline stem cells (FGSCs) is controversial because of questions regarding the reliability and stability of the isolation method using antibody targeting mouse vasa homologue (MVH), and the molecular mechanism of FGSCs self-renewal remains unclear. Thus, there needs to be a simple and reliable method for sorting FGSCs to study them. We applied the differential adhesion method to enrich FGSCs (DA-FGSCs) from mouse ovaries. Through four rounds of purification and 7-9 subsequent passages, DA-FGSC lines were established. In addition, we assessed the role of the phosphoinositide-3 kinase (PI3K)-AKT pathway in regulating FGSC self-renewal. The obtained DA-FGSCs spontaneously differentiated into oocyte-like cells in vitro and formed functional eggs in vivo that were fertilized and produced healthy offspring. AKT was rapidly phosphorylated when the proliferation rate of FGSCs increased after 10 passages, and the addition of a chemical PI3K inhibitor prevented FGSCs self-renewal. Furthermore, over-expression of AKT-induced proliferation and differentiation of FGSCs, c-Myc, Oct-4 and Gdf-9 levels were increased. The differential adhesion method provides a more feasible approach and is an easier procedure to establish FGSC lines than traditional methods. The AKT pathway plays an important role in regulation of the proliferation and maintenance of FGSCs. These findings could help promote stem cell studies and provide a better understanding of causes of ovarian infertility, thereby providing potential treatments for infertility. © 2018 The Author(s). Published by S. Karger AG, Basel.

Germline stem cell gene PIWIL2 mediates DNA repair through relaxation of chromatin.

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De-Tao Yin

Full Text Available DNA damage response (DDR is an intrinsic barrier of cell to tumorigenesis initiated by genotoxic agents. However, the mechanisms underlying the DDR are not completely understood despite of extensive investigation. Recently, we have reported that ectopic expression of germline stem cell gene PIWIL2 is associated with tumor stem cell development, although the underlying mechanisms are largely unknown. Here we show that PIWIL2 is required for the repair of DNA-damage induced by various types of genotoxic agents. Upon ultraviolet (UV irradiation, silenced PIWIL2 gene in normal human fibroblasts was transiently activated after treatment with UV light. This activation was associated with DNA repair, because Piwil2-deficienct mouse embryonic fibroblasts (mili(-/- MEFs were defective in cyclobutane pyrimidine dimers (CPD repair after UV treatment. As a result, the UV-treated mili(-/- MEFs were more susceptible to apoptosis, as characterized by increased levels of DNA damage-associated apoptotic proteins, such as active caspase-3, cleaved Poly (ADP-ribose polymerase (PARP and Bik. The impaired DNA repair in the mili(-/- MEFs was associated with the reductions of histone H3 acetylation and chromatin relaxation, although the DDR pathway downstream chromatin relaxation appeared not to be directly affected by Piwil2. Moreover, guanine-guanine (Pt-[GG] and double strand break (DSB repair were also defective in the mili(-/- MEFs treated by genotoxic chemicals Cisplatin and ionizing radiation (IR, respectively. The results indicate that Piwil2 can mediate DNA repair through an axis of Piwil2 → histone acetylation → chromatin relaxation upstream DDR pathways. The findings reveal a new role for Piwil2 in DNA repair and suggest that Piwil2 may act as a gatekeeper against DNA damage-mediated tumorigenesis.

Drosophila's contribution to stem cell research [version 2; referees: 2 approved

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Gyanesh Singh

2016-08-01

Full Text Available 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.

Ovarian Stem Cell Nests in Reproduction and Ovarian Aging.

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Ye, Haifeng; Zheng, Tuochen; Li, Wei; Li, Xiaoyan; Fu, Xinxin; Huang, Yaoqi; Hu, Chuan; Li, Jia; Huang, Jian; Liu, Zhengyv; Zheng, Liping; Zheng, Yuehui

2017-01-01

The fixed primordial follicles pool theory, which monopolized reproductive medicine for more than one hundred years, has been broken by the discovery, successful isolation and establishment of ovarian stem cells. It has brought more hope than ever of increasing the size of primordial follicle pool, improving ovarian function and delaying ovarian consenescence. Traditional view holds that stem cell aging contributes to the senility of body and organs. However, in the process of ovarian aging, the main factor leading to the decline of the reproductive function is the aging and degradation of ovarian stem cell nests, rather than the senescence of ovarian germ cells themselves. Recent studies have found that the immune system and circulatory system are involved in the formation of ovarian germline stem cell niches, as well as regulating the proliferation and differentiation of ovarian germline stem cells through cellular and hormonal signals. Therefore, we can improve ovarian function and delay ovarian aging by improving the immune system and circulatory system, which will provide an updated program for the treatment of premature ovarian failure (POF) and infertility. © 2017 The Author(s). Published by S. Karger AG, Basel.

Control of germline stem cell self-renewal and differentiation in the Drosophila ovary: concerted actions of niche signals and intrinsic factors.

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Xie, Ting

2013-01-01

In the Drosophila ovary, germline stem cells (GSCs) physically interact with their niche composed of terminal filament cells, cap cells, and possibly GSC-contacting escort cells (ECs). A GSC divides to generate a self-renewing stem cell that remains in the niche and a differentiating daughter that moves away from the niche. The GSC niche provides a bone morphogenetic protein (BMP) signal that maintains GSC self-renewal by preventing stem cell differentiation via repression of the differentiation-promoting gene bag of marbles (bam). In addition, it expresses E-cadherin, which mediates cell adhesion for anchoring GSCs in the niche, enabling continuous self-renewal. GSCs themselves also express different classes of intrinsic factors, including signal transducers, transcription factors, chromatin remodeling factors, translation regulators, and miRNAs, which control self-renewal by strengthening interactions with the niche and repressing various differentiation pathways. Differentiated GSC daughters, known as cystoblasts (CBs), also express distinct classes of intrinsic factors to inhibit self-renewal and promote germ cell differentiation. Surprisingly, GSC progeny are also dependent on their surrounding ECs for proper differentiation at least partly by preventing BMP from diffusing to the differentiated germ cell zone and by repressing ectopic BMP expression. Therefore, both GSC self-renewal and CB differentiation are controlled by collaborative actions of extrinsic signals and intrinsic factors. Copyright © 2012 Wiley Periodicals, Inc.

Genome engineering through CRISPR/Cas9 technology in the human germline and pluripotent stem cells.

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Vassena, R; Heindryckx, B; Peco, R; Pennings, G; Raya, A; Sermon, K; Veiga, A

2016-06-01

With the recent development of CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 genome editing technology, the possibility to genetically manipulate the human germline (gametes and embryos) has become a distinct technical possibility. Although many technical challenges still need to be overcome in order to achieve adequate efficiency and precision of the technology in human embryos, the path leading to genome editing has never been simpler, more affordable, and widespread. In this narrative review we seek to understand the possible impact of CRISR/Cas9 technology on human reproduction from the technical and ethical point of view, and suggest a course of action for the scientific community. This non-systematic review was carried out using Medline articles in English, as well as technical documents from the Human Fertilisation and Embryology Authority and reports in the media. The technical possibilities of the CRISPR/Cas9 technology with regard to human reproduction are analysed based on results obtained in model systems such as large animals and laboratory rodents. Further, the possibility of CRISPR/Cas9 use in the context of human reproduction, to modify embryos, germline cells, and pluripotent stem cells is reviewed based on the authors' expert opinion. Finally, the possible uses and consequences of CRISPR/cas9 gene editing in reproduction are analysed from the ethical point of view. We identify critical technical and ethical issues that should deter from employing CRISPR/Cas9 based technologies in human reproduction until they are clarified. Overcoming the numerous technical limitations currently associated with CRISPR/Cas9 mediated editing of the human germline will depend on intensive research that needs to be transparent and widely disseminated. Rather than a call to a generalized moratorium, or banning, of this type of research, efforts should be placed on establishing an open, international, collaborative and regulated research

Specific Tandem 3'UTR Patterns and Gene Expression Profiles in Mouse Thy1+ Germline Stem Cells.

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Yan Huang

Full Text Available A recently developed strategy of sequencing alternative polyadenylation (APA sites (SAPAS with second-generation sequencing technology can be used to explore complete genome-wide patterns of tandem APA sites and global gene expression profiles. spermatogonial stem cells (SSCs maintain long-term reproductive abilities in male mammals. The detailed mechanisms by which SSCs self-renew and generate mature spermatozoa are not clear. To understand the specific alternative polyadenylation pattern and global gene expression profile of male germline stem cells (GSCs, mainly referred to SSCs here, we isolated and purified mouse Thy1+ cells from testis by magnetic-activated cell sorting (MACS and then used the SAPAS method for analysis, using pluripotent embryonic stem cells (ESCs and differentiated mouse embryonic fibroblast cells (MEFs as controls. As a result, we obtained 99,944 poly(A sites, approximately 40% of which were newly detected in our experiments. These poly(A sites originated from three mouse cell types and covered 17,499 genes, including 831 long non-coding RNA (lncRNA genes. We observed that GSCs tend to have shorter 3'UTR lengths while MEFs tend towards longer 3'UTR lengths. We also identified 1337 genes that were highly expressed in GSCs, and these genes were highly consistent with the functional characteristics of GSCs. Our detailed bioinformatics analysis identified APA site-switching events at 3'UTRs and many new specifically expressed genes in GSCs, which we experimentally confirmed. Furthermore, qRT-PCR was performed to validate several events of the 334 genes with distal-to-proximal poly(A switch in GSCs. Consistently APA reporter assay confirmed the total 3'UTR shortening in GSCs compared to MEFs. We also analyzed the cis elements around the proximal poly(A site preferentially used in GSCs and found C-rich elements may contribute to this regulation. Overall, our results identified the expression level and polyadenylation site

Specific Tandem 3'UTR Patterns and Gene Expression Profiles in Mouse Thy1+ Germline Stem Cells

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Lin, Zhuoheng; Feng, Xuyang; Jiang, Xue; Songyang, Zhou; Huang, Junjiu

2015-01-01

A recently developed strategy of sequencing alternative polyadenylation (APA) sites (SAPAS) with second-generation sequencing technology can be used to explore complete genome-wide patterns of tandem APA sites and global gene expression profiles. spermatogonial stem cells (SSCs) maintain long-term reproductive abilities in male mammals. The detailed mechanisms by which SSCs self-renew and generate mature spermatozoa are not clear. To understand the specific alternative polyadenylation pattern and global gene expression profile of male germline stem cells (GSCs, mainly referred to SSCs here), we isolated and purified mouse Thy1+ cells from testis by magnetic-activated cell sorting (MACS) and then used the SAPAS method for analysis, using pluripotent embryonic stem cells (ESCs) and differentiated mouse embryonic fibroblast cells (MEFs) as controls. As a result, we obtained 99,944 poly(A) sites, approximately 40% of which were newly detected in our experiments. These poly(A) sites originated from three mouse cell types and covered 17,499 genes, including 831 long non-coding RNA (lncRNA) genes. We observed that GSCs tend to have shorter 3'UTR lengths while MEFs tend towards longer 3'UTR lengths. We also identified 1337 genes that were highly expressed in GSCs, and these genes were highly consistent with the functional characteristics of GSCs. Our detailed bioinformatics analysis identified APA site-switching events at 3'UTRs and many new specifically expressed genes in GSCs, which we experimentally confirmed. Furthermore, qRT-PCR was performed to validate several events of the 334 genes with distal-to-proximal poly(A) switch in GSCs. Consistently APA reporter assay confirmed the total 3'UTR shortening in GSCs compared to MEFs. We also analyzed the cis elements around the proximal poly(A) site preferentially used in GSCs and found C-rich elements may contribute to this regulation. Overall, our results identified the expression level and polyadenylation site profiles and

Oyster vasa-like gene as a marker of the germline cell development in Crassostrea gigas

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Fabioux, C.; Huvet, A.; Lelong, C.; Robert, R.; Pouvreau, S.; Daniel, J.Y.; Minguant, C.; Le Pennec, M.

2004-01-01

The oyster vasa-like gene was previously demonstrated to be specifically expressed in germline cells of adult oysters Crassostrea gigas. In the present study, this gene was used as a molecular marker to establish the developmental pattern of germline cells during oyster ontogenesis, using whole-mount in situ hybridization and real-time PCR. The Oyvlg transcripts appeared to be localized to the vegetal pole of unfertilized oocytes and maternally transmitted to embryos. At early development, these maternal transcripts were observed to segregate into a single blastomere, from the CD macromere of 2-cell stage to the 4d mesentoblast of blastula. From late blastula stage, the mesentoblast divided into two cell clumps that migrated to both sides of the larvae body and that would correspond to primordial germ cells (PGCs). Based on these results, we postulate that the germline of C. gigas is specified at early development by maternal cytoplasmic determinants including Oyvlg mRNAs, in putative PGCs that would differentiate into germinal stem cells in juvenile oysters

DIP1 modulates stem cell homeostasis in Drosophila through regulation of sisR-1.

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Wong, Jing Ting; Akhbar, Farzanah; Ng, Amanda Yunn Ee; Tay, Mandy Li-Ian; Loi, Gladys Jing En; Pek, Jun Wei

2017-10-02

Stable intronic sequence RNAs (sisRNAs) are by-products of splicing and regulate gene expression. How sisRNAs are regulated is unclear. Here we report that a double-stranded RNA binding protein, Disco-interacting protein 1 (DIP1) regulates sisRNAs in Drosophila. DIP1 negatively regulates the abundance of sisR-1 and INE-1 sisRNAs. Fine-tuning of sisR-1 by DIP1 is important to maintain female germline stem cell homeostasis by modulating germline stem cell differentiation and niche adhesion. Drosophila DIP1 localizes to a nuclear body (satellite body) and associates with the fourth chromosome, which contains a very high density of INE-1 transposable element sequences that are processed into sisRNAs. DIP1 presumably acts outside the satellite bodies to regulate sisR-1, which is not on the fourth chromosome. Thus, our study identifies DIP1 as a sisRNA regulatory protein that controls germline stem cell self-renewal in Drosophila.Stable intronic sequence RNAs (sisRNAs) are by-products of splicing from introns with roles in embryonic development in Drosophila. Here, the authors show that the RNA binding protein DIP1 regulates sisRNAs in Drosophila, which is necessary for germline stem cell homeostasis.

Sex, stem cells and tumors in the Drosophila ovary.

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Salz, Helen K

2013-01-01

The Drosophila Sex-lethal (Sxl) gene encodes a female-specific RNA binding protein that in somatic cells globally regulates all aspects of female-specific development and behavior. Sxl also has a critical, but less well understood, role in female germ cells. Germ cells without Sxl protein can adopt a stem cell fate when housed in a normal ovary, but fail to successfully execute the self-renewal differentiation fate switch. The failure to differentiate is accompanied by the inappropriate expression of a set of male specific markers, continued proliferation, and formation of a tumor. The findings in Chau et al., (2012) identify the germline stem cell maintenance factor nanos as one of its target genes, and suggest that Sxl enables the switch from germline stem cell to committed daughter cell by posttranscriptional downregulation of nanos expression. These studies provide the basis for a new model in which Sxl directly couples sexual identity with the self-renewal differentiation decision and raises several interesting questions about the genesis of the tumor phenotype.

In Vitro Derivation and Propagation of Spermatogonial Stem Cell Activity from Mouse Pluripotent Stem Cells.

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Ishikura, Yukiko; Yabuta, Yukihiro; Ohta, Hiroshi; Hayashi, Katsuhiko; Nakamura, Tomonori; Okamoto, Ikuhiro; Yamamoto, Takuya; Kurimoto, Kazuki; Shirane, Kenjiro; Sasaki, Hiroyuki; Saitou, Mitinori

2016-12-06

The in vitro derivation and propagation of spermatogonial stem cells (SSCs) from pluripotent stem cells (PSCs) is a key goal in reproductive science. We show here that when aggregated with embryonic testicular somatic cells (reconstituted testes), primordial germ cell-like cells (PGCLCs) induced from mouse embryonic stem cells differentiate into spermatogonia-like cells in vitro and are expandable as cells that resemble germline stem cells (GSCs), a primary cell line with SSC activity. Remarkably, GSC-like cells (GSCLCs), but not PGCLCs, colonize adult testes and, albeit less effectively than GSCs, contribute to spermatogenesis and fertile offspring. Whole-genome analyses reveal that GSCLCs exhibit aberrant methylation at vulnerable regulatory elements, including those critical for spermatogenesis, which may restrain their spermatogenic potential. Our study establishes a strategy for the in vitro derivation of SSC activity from PSCs, which, we propose, relies on faithful epigenomic regulation. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Cell-nonautonomous signaling of FOXO/DAF-16 to the stem cells of Caenorhabditis elegans.

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Wenjing Qi

Full Text Available In Caenorhabditis elegans (C. elegans, the promotion of longevity by the transcription factor DAF-16 requires reduced insulin/IGF receptor (IIR signaling or the ablation of the germline, although the reason for the negative impact of germ cells is unknown. FOXO/DAF-16 activity inhibits germline proliferation in both daf-2 mutants and gld-1 tumors. In contrast to its function as a germline tumor suppressor, we now provide evidence that somatic DAF-16 in the presence of IIR signaling can also result in tumorigenic activity, which counteracts robust lifespan extension. In contrast to the cell-autonomous IIR signaling, which is required for larval germline proliferation, activation of DAF-16 in the hypodermis results in hyperplasia of the germline and disruption of the surrounding basement membrane. SHC-1 adaptor protein and AKT-1 kinase antagonize, whereas AKT-2 and SGK-1 kinases promote, this cell-nonautonomous DAF-16 function. Our data suggest that a functional balance of DAF-16 activities in different tissues determines longevity and reveals a novel, cell-nonautonomous role of FOXO/DAF-16 to affect stem cells.

Cell-Nonautonomous Signaling of FOXO/DAF-16 to the Stem Cells of Caenorhabditis elegans

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Qi, Wenjing; Huang, Xu; Neumann-Haefelin, Elke; Schulze, Ekkehard; Baumeister, Ralf

2012-01-01

In Caenorhabditis elegans (C. elegans), the promotion of longevity by the transcription factor DAF-16 requires reduced insulin/IGF receptor (IIR) signaling or the ablation of the germline, although the reason for the negative impact of germ cells is unknown. FOXO/DAF-16 activity inhibits germline proliferation in both daf-2 mutants and gld-1 tumors. In contrast to its function as a germline tumor suppressor, we now provide evidence that somatic DAF-16 in the presence of IIR signaling can also result in tumorigenic activity, which counteracts robust lifespan extension. In contrast to the cell-autonomous IIR signaling, which is required for larval germline proliferation, activation of DAF-16 in the hypodermis results in hyperplasia of the germline and disruption of the surrounding basement membrane. SHC-1 adaptor protein and AKT-1 kinase antagonize, whereas AKT-2 and SGK-1 kinases promote, this cell-nonautonomous DAF-16 function. Our data suggest that a functional balance of DAF-16 activities in different tissues determines longevity and reveals a novel, cell-nonautonomous role of FOXO/DAF-16 to affect stem cells. PMID:22916022

Temporal remodeling of the cell cycle accompanies differentiation in the Drosophila germline.

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Hinnant, Taylor D; Alvarez, Arturo A; Ables, Elizabeth T

2017-09-01

Development of multicellular organisms relies upon the coordinated regulation of cellular differentiation and proliferation. Growing evidence suggests that some molecular regulatory pathways associated with the cell cycle machinery also dictate cell fate; however, it remains largely unclear how the cell cycle is remodeled in concert with cell differentiation. During Drosophila oogenesis, mature oocytes are created through a series of precisely controlled division and differentiation steps, originating from a single tissue-specific stem cell. Further, germline stem cells (GSCs) and their differentiating progeny remain in a predominantly linear arrangement as oogenesis proceeds. The ability to visualize the stepwise events of differentiation within the context of a single tissue make the Drosophila ovary an exceptional model for study of cell cycle remodeling. To describe how the cell cycle is remodeled in germ cells as they differentiate in situ, we used the Drosophila Fluorescence Ubiquitin-based Cell Cycle Indicator (Fly-FUCCI) system, in which degradable versions of GFP::E2f1 and RFP::CycB fluorescently label cells in each phase of the cell cycle. We found that the lengths of the G1, S, and G2 phases of the cell cycle change dramatically over the course of differentiation, and identified the 4/8-cell cyst as a key developmental transition state in which cells prepare for specialized cell cycles. Our data suggest that the transcriptional activator E2f1, which controls the transition from G1 to S phase, is a key regulator of mitotic divisions in the early germline. Our data support the model that E2f1 is necessary for proper GSC proliferation, self-renewal, and daughter cell development. In contrast, while E2f1 degradation by the Cullin 4 (Cul4)-containing ubiquitin E3 ligase (CRL4) is essential for developmental transitions in the early germline, our data do not support a role for E2f1 degradation as a mechanism to limit GSC proliferation or self-renewal. Taken

Intestinal stem cells in the adult Drosophila midgut

International Nuclear Information System (INIS)

Jiang, Huaqi; Edgar, Bruce A.

2011-01-01

Drosophila has long been an excellent model organism for studying stem cell biology. Notably, studies of Drosophila's germline stem cells have been instrumental in developing the stem cell niche concept. The recent discovery of somatic stem cells in adult Drosophila, particularly the intestinal stem cells (ISCs) of the midgut, has established Drosophila as an exciting model to study stem cell-mediated adult tissue homeostasis and regeneration. Here, we review the major signaling pathways that regulate the self-renewal, proliferation and differentiation of Drosophila ISCs, discussing how this regulation maintains midgut homeostasis and mediates regeneration of the intestinal epithelium after injury. -- Highlights: ► The homeostasis and regeneration of adult fly midguts are mediated by ISCs. ► Damaged enterocytes induce the proliferation of intestinal stem cells (ISC). ► EGFR and Jak/Stat signalings mediate compensatory ISC proliferation. ► Notch signaling regulates ISC self-renewal and differentiation.

Structural polarity and dynamics of male germline stem cells in an insect (milkweed bug Oncopeltus fasciatus).

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Dorn, David C; Dorn, August

2008-01-01

Knowing the structure opens a door for a better understanding of function because there is no function without structure. Male germline stem cells (GSCs) of the milkweed bug (Oncopeltus fasciatus) exhibit a very extraordinary structure and a very special relationship with their niche, the apical cells. This structural relationship is strikingly different from that known in the fruit fly (Drosophila melanogaster) -- the most successful model system, which allowed deep insights into the signaling interactions between GSCs and niche. The complex structural polarity of male GSCs in the milkweed bug combined with their astonishing dynamics suggest that cell morphology and dynamics are causally related with the most important regulatory processes that take place between GSCs and niche and ensure maintenance, proliferation, and differentiation of GSCs in accordance with the temporal need of mature sperm. The intricate structure of the GSCs of the milkweed bug (and probably of some other insects, i.e., moths) is only accessible by electron microscopy. But, studying singular sections through the apical complex (i.e., GSCs and apical cells) is not sufficient to obtain a full picture of the GSCs; especially, the segregation of projection terminals is not tangible. Only serial sections and their overlay can establish whether membrane ingrowths merely constrict projections or whether a projection terminal is completely cut off. To sequence the GSC dynamics, it is necessary to include juvenile stages, when the processes start and the GSCs occur in small numbers. The fine structural analysis of segregating projection terminals suggests that these terminals undergo autophagocytosis. Autophagosomes can be labeled by markers. We demonstrated acid phosphatase and thiamine pyrophosphatase (TPPase). Both together are thought to identify autophagosomes. Using the appropriate substrate of the enzymes and cerium chloride, the precipitation of electron-dense cerium phosphate granules

Genome editing in mouse spermatogonial stem/progenitor cells using engineered nucleases.

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Danielle A Fanslow

Full Text Available Editing the genome to create specific sequence modifications is a powerful way to study gene function and promises future applicability to gene therapy. Creation of precise modifications requires homologous recombination, a very rare event in most cell types that can be stimulated by introducing a double strand break near the target sequence. One method to create a double strand break in a particular sequence is with a custom designed nuclease. We used engineered nucleases to stimulate homologous recombination to correct a mutant gene in mouse "GS" (germline stem cells, testicular derived cell cultures containing spermatogonial stem cells and progenitor cells. We demonstrated that gene-corrected cells maintained several properties of spermatogonial stem/progenitor cells including the ability to colonize following testicular transplantation. This proof of concept for genome editing in GS cells impacts both cell therapy and basic research given the potential for GS cells to be propagated in vitro, contribute to the germline in vivo following testicular transplantation or become reprogrammed to pluripotency in vitro.

Roles of Mitochondrial DNA Mutations in Stem Cell Ageing

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Tianhong Su

2018-03-01

Full Text Available Mitochondrial DNA (mtDNA mutations accumulate in somatic stem cells during ageing and cause mitochondrial dysfunction. In this review, we summarize the studies that link mtDNA mutations to stem cell ageing. We discuss the age-related behaviours of the somatic mtDNA mutations in stem cell populations and how they potentially contribute to stem cell ageing by altering mitochondrial properties in humans and in mtDNA-mutator mice. We also draw attention to the diverse fates of the mtDNA mutations with different origins during ageing, with potential selective pressures on the germline inherited but not the somatic mtDNA mutations.

C. elegans DAF-16/FOXO interacts with TGF-ß/BMP signaling to induce germline tumor formation via mTORC1 activation.

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Wenjing Qi

2017-05-01

Full Text Available Activation of the FOXO transcription factor DAF-16 by reduced insulin/IGF signaling (IIS is considered to be beneficial in C. elegans due to its ability to extend lifespan and to enhance stress resistance. In the germline, cell-autonomous DAF-16 activity prevents stem cell proliferation, thus acting tumor-suppressive. In contrast, hypodermal DAF-16 causes a tumorous germline phenotype characterized by hyperproliferation of the germline stem cells and rupture of the adjacent basement membrane. Here we show that cross-talk between DAF-16 and the transforming growth factor ß (TGFß/bone morphogenic protein (BMP signaling pathway causes germline hyperplasia and results in disruption of the basement membrane. In addition to activating MADM/NRBP/hpo-11 gene alone, DAF-16 also directly interacts with both R-SMAD proteins SMA-2 and SMA-3 in the nucleus to regulate the expression of mTORC1 pathway. Knocking-down of BMP genes or each of the four target genes in the hypodermis was sufficient to inhibit germline proliferation, indicating a cell-non-autonomously controlled regulation of stem cell proliferation by somatic tissues. We propose the existence of two antagonistic DAF-16/FOXO functions, a cell-proliferative somatic and an anti-proliferative germline activity. Whereas germline hyperplasia under reduced IIS is inhibited by DAF-16 cell-autonomously, activation of somatic DAF-16 in the presence of active IIS promotes germline proliferation and eventually induces tumor-like germline growth. In summary, our results suggest a novel pathway crosstalk of DAF-16 and TGF-ß/BMP that can modulate mTORC1 at the transcriptional level to cause stem-cell hyperproliferation. Such cell-type specific differences may help explaining why human FOXO activity is considered to be tumor-suppressive in most contexts, but may become oncogenic, e.g. in chronic and acute myeloid leukemia.

C. elegans DAF-16/FOXO interacts with TGF-ß/BMP signaling to induce germline tumor formation via mTORC1 activation.

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Qi, Wenjing; Yan, Yijian; Pfeifer, Dietmar; Donner V Gromoff, Erika; Wang, Yimin; Maier, Wolfgang; Baumeister, Ralf

2017-05-01

Activation of the FOXO transcription factor DAF-16 by reduced insulin/IGF signaling (IIS) is considered to be beneficial in C. elegans due to its ability to extend lifespan and to enhance stress resistance. In the germline, cell-autonomous DAF-16 activity prevents stem cell proliferation, thus acting tumor-suppressive. In contrast, hypodermal DAF-16 causes a tumorous germline phenotype characterized by hyperproliferation of the germline stem cells and rupture of the adjacent basement membrane. Here we show that cross-talk between DAF-16 and the transforming growth factor ß (TGFß)/bone morphogenic protein (BMP) signaling pathway causes germline hyperplasia and results in disruption of the basement membrane. In addition to activating MADM/NRBP/hpo-11 gene alone, DAF-16 also directly interacts with both R-SMAD proteins SMA-2 and SMA-3 in the nucleus to regulate the expression of mTORC1 pathway. Knocking-down of BMP genes or each of the four target genes in the hypodermis was sufficient to inhibit germline proliferation, indicating a cell-non-autonomously controlled regulation of stem cell proliferation by somatic tissues. We propose the existence of two antagonistic DAF-16/FOXO functions, a cell-proliferative somatic and an anti-proliferative germline activity. Whereas germline hyperplasia under reduced IIS is inhibited by DAF-16 cell-autonomously, activation of somatic DAF-16 in the presence of active IIS promotes germline proliferation and eventually induces tumor-like germline growth. In summary, our results suggest a novel pathway crosstalk of DAF-16 and TGF-ß/BMP that can modulate mTORC1 at the transcriptional level to cause stem-cell hyperproliferation. Such cell-type specific differences may help explaining why human FOXO activity is considered to be tumor-suppressive in most contexts, but may become oncogenic, e.g. in chronic and acute myeloid leukemia.

Intestinal stem cells in the adult Drosophila midgut

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Jiang, Huaqi, E-mail: Huaqi.Jiang@UTSouthwestern.edu [Department of Developmental Biology, UT Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75235 (United States); Edgar, Bruce A., E-mail: b.edgar@dkfz.de [ZMBH-DKFZ Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg (Germany); Division of Basic Sciences, Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Seattle, WA 98109 (United States)

2011-11-15

Drosophila has long been an excellent model organism for studying stem cell biology. Notably, studies of Drosophila's germline stem cells have been instrumental in developing the stem cell niche concept. The recent discovery of somatic stem cells in adult Drosophila, particularly the intestinal stem cells (ISCs) of the midgut, has established Drosophila as an exciting model to study stem cell-mediated adult tissue homeostasis and regeneration. Here, we review the major signaling pathways that regulate the self-renewal, proliferation and differentiation of Drosophila ISCs, discussing how this regulation maintains midgut homeostasis and mediates regeneration of the intestinal epithelium after injury. -- Highlights: Black-Right-Pointing-Pointer The homeostasis and regeneration of adult fly midguts are mediated by ISCs. Black-Right-Pointing-Pointer Damaged enterocytes induce the proliferation of intestinal stem cells (ISC). Black-Right-Pointing-Pointer EGFR and Jak/Stat signalings mediate compensatory ISC proliferation. Black-Right-Pointing-Pointer Notch signaling regulates ISC self-renewal and differentiation.

The CCR4 Deadenylase Acts with Nanos and Pumilio in the Fine-Tuning of Mei-P26 Expression to Promote Germline Stem Cell Self-Renewal

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Joly, Willy; Chartier, Aymeric; Rojas-Rios, Patricia; Busseau, Isabelle; Simonelig, Martine

2013-01-01

Summary Translational regulation plays an essential role in Drosophila ovarian germline stem cell (GSC) biology. GSC self-renewal requires two translational repressors, Nanos (Nos) and Pumilio (Pum), which repress the expression of differentiation factors in the stem cells. The molecular mechanisms underlying this translational repression remain unknown. Here, we show that the CCR4 deadenylase is required for GSC self-renewal and that Nos and Pum act through its recruitment onto specific mRNAs. We identify mei-P26 mRNA as a direct and major target of Nos/Pum/CCR4 translational repression in the GSCs. mei-P26 encodes a protein of the Trim-NHL tumor suppressor family that has conserved functions in stem cell lineages. We show that fine-tuning Mei-P26 expression by CCR4 plays a key role in GSC self-renewal. These results identify the molecular mechanism of Nos/Pum function in GSC self-renewal and reveal the role of CCR4-NOT-mediated deadenylation in regulating the balance between GSC self-renewal and differentiation. PMID:24286029

The CCR4 deadenylase acts with Nanos and Pumilio in the fine-tuning of Mei-P26 expression to promote germline stem cell self-renewal.

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Joly, Willy; Chartier, Aymeric; Rojas-Rios, Patricia; Busseau, Isabelle; Simonelig, Martine

2013-01-01

Translational regulation plays an essential role in Drosophila ovarian germline stem cell (GSC) biology. GSC self-renewal requires two translational repressors, Nanos (Nos) and Pumilio (Pum), which repress the expression of differentiation factors in the stem cells. The molecular mechanisms underlying this translational repression remain unknown. Here, we show that the CCR4 deadenylase is required for GSC self-renewal and that Nos and Pum act through its recruitment onto specific mRNAs. We identify mei-P26 mRNA as a direct and major target of Nos/Pum/CCR4 translational repression in the GSCs. mei-P26 encodes a protein of the Trim-NHL tumor suppressor family that has conserved functions in stem cell lineages. We show that fine-tuning Mei-P26 expression by CCR4 plays a key role in GSC self-renewal. These results identify the molecular mechanism of Nos/Pum function in GSC self-renewal and reveal the role of CCR4-NOT-mediated deadenylation in regulating the balance between GSC self-renewal and differentiation.

Minichromosome maintenance helicase paralog MCM9 is dispensible for DNA replication but functions in germ-line stem cells and tumor suppression.

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Hartford, Suzanne A; Luo, Yunhai; Southard, Teresa L; Min, Irene M; Lis, John T; Schimenti, John C

2011-10-25

Effective DNA replication is critical to the health and reproductive success of organisms. The six MCM2-7 proteins, which form the replicative helicase, are essential for high-fidelity replication of the genome. Many eukaryotes have a divergent paralog, MCM9, that was reported to be essential for loading MCM2-7 onto replication origins in the Xenopus oocyte extract system. To address the in vivo role of mammalian MCM9, we created and analyzed the phenotypes of mice with various mutations in Mcm9 and an intronic DNA replication-related gene Asf1a. Ablation of Mcm9 was compatible with cell proliferation and mouse viability, showing that it is nonessential for MCM2-7 loading or DNA replication. Mcm9 mutants underwent p53-independent embryonic germ-cell depletion in both sexes, with males also exhibiting defective spermatogonial stem-cell renewal. MCM9-deficient cells had elevated genomic instability and defective cell cycle reentry following replication stress, and mutant animals were prone to sex-specific cancers, most notably hepatocellular carcinoma in males. The phenotypes of mutant mice and cells suggest that MCM9 evolved a specialized but nonessential role in DNA replication or replication-linked quality-control mechanisms that are especially important for germ-line stem cells, and also for tumor suppression and genome maintenance in the soma.

Vasa promotes Drosophila germline stem cell differentiation by activating mei-P26 translation by directly interacting with a (U)-rich motif in its 3' UTR.

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Liu, Niankun; Han, Hong; Lasko, Paul

2009-12-01

Vasa (Vas) is a DEAD-box RNA-binding protein required in Drosophila at several steps of oogenesis and for primordial germ cell (PGC) specification. Vas associates with eukaryotic initiation factor 5B (eIF5B), and this interaction has been implicated in translational activation of gurken mRNA in the oocyte. Vas is expressed in all ovarian germline cells, and aspects of the vas-null phenotype suggest a function in regulating the balance between germline stem cells (GSCs) and their fate-restricted descendants. We used a biochemical approach to recover Vas-associated mRNAs and obtained mei-P26, whose product represses microRNA activity and promotes GSC differentiation. We found that vas and mei-P26 mutants interact, and that mei-P26 translation is substantially reduced in vas mutant cells. In vitro, Vas protein bound specifically to a (U)-rich motif in the mei-P26 3' untranslated region (UTR), and Vas-dependent regulation of GFP-mei-P26 transgenes in vivo was dependent on the same (U)-rich 3' UTR domain. The ability of Vas to activate mei-P26 expression in vivo was abrogated by a mutation that greatly reduces its interaction with eIF5B. Taken together, our data support the conclusion that Vas promotes germ cell differentiation by directly activating mei-P26 translation in early-stage committed cells.

Aging-Induced Stem Cell Mutations as Drivers for Disease and Cancer

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Adams, Peter D.; Jasper, Heinrich; Rudolph, K. Lenhard

2015-01-01

Aging is characterized by a decrease in genome integrity, impaired organ maintenance, and an increased risk of cancer, which coincide with clonal dominance of expanded mutant stem and progenitor cell populations in aging tissues, such as the intestinal epithelium, the hematopoietic system, and the male germline. Here we discuss possible explanations for age-associated increases in the initiation and/or progression of mutant stem/progenitor clones and highlight the roles of stem cell quiescence, replication-associated DNA damage, telomere shortening, epigenetic alterations, and metabolic challenges as determinants of stem cell mutations and clonal dominance in aging. PMID:26046760

Germline progenitors escape the widespread phenomenon of homolog pairing during Drosophila development.

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Eric F Joyce

Full Text Available Homolog pairing, which plays a critical role in meiosis, poses a potential risk if it occurs in inappropriate tissues or between nonallelic sites, as it can lead to changes in gene expression, chromosome entanglements, and loss-of-heterozygosity due to mitotic recombination. This is particularly true in Drosophila, which supports organismal-wide pairing throughout development. Discovered over a century ago, such extensive pairing has led to the perception that germline pairing in the adult gonad is an extension of the pairing established during embryogenesis and, therefore, differs from the mechanism utilized in most species to initiate pairing specifically in the germline. Here, we show that, contrary to long-standing assumptions, Drosophila meiotic pairing in the gonad is not an extension of pairing established during embryogenesis. Instead, we find that homologous chromosomes are unpaired in primordial germ cells from the moment the germline can be distinguished from the soma in the embryo and remain unpaired even in the germline stem cells of the adult gonad. We further establish that pairing originates immediately after the stem cell stage. This pairing occurs well before the initiation of meiosis and, strikingly, continues through the several mitotic divisions preceding meiosis. These discoveries indicate that the spatial organization of the Drosophila genome differs between the germline and the soma from the earliest moments of development and thus argue that homolog pairing in the germline is an active process as versus a passive continuation of pairing established during embryogenesis.

The niche-derived glial cell line-derived neurotrophic factor (GDNF induces migration of mouse spermatogonial stem/progenitor cells.

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Lisa Dovere

Full Text Available In mammals, the biological activity of the stem/progenitor compartment sustains production of mature gametes through spermatogenesis. Spermatogonial stem cells and their progeny belong to the class of undifferentiated spermatogonia, a germ cell population found on the basal membrane of the seminiferous tubules. A large body of evidence has demonstrated that glial cell line-derived neurotrophic factor (GDNF, a Sertoli-derived factor, is essential for in vivo and in vitro stem cell self-renewal. However, the mechanisms underlying this activity are not completely understood. In this study, we show that GDNF induces dose-dependent directional migration of freshly selected undifferentiated spermatogonia, as well as germline stem cells in culture, using a Boyden chamber assay. GDNF-induced migration is dependent on the expression of the GDNF co-receptor GFRA1, as shown by migration assays performed on parental and GFRA1-transduced GC-1 spermatogonial cell lines. We found that the actin regulatory protein vasodilator-stimulated phosphoprotein (VASP is specifically expressed in undifferentiated spermatogonia. VASP belongs to the ENA/VASP family of proteins implicated in actin-dependent processes, such as fibroblast migration, axon guidance, and cell adhesion. In intact seminiferous tubules and germline stem cell cultures, GDNF treatment up-regulates VASP in a dose-dependent fashion. These data identify a novel role for the niche-derived factor GDNF, and they suggest that GDNF may impinge on the stem/progenitor compartment, affecting the actin cytoskeleton and cell migration.

Optimization of three-dimensional imaging on in vitro produced porcine blastocysts and chimeras for stem cell testing

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Secher, Jan Ole Bertelsen; Freude, Kristine; Li, Rong

2015-01-01

. This is relevant for testing of presumed pluripotent stem cells. The gold standard for pluripotent stem cells is to test if the cells are capable of contributing to germline chimeras. Differential staining can be used to evaluate the possibility of chimeric contribution; if the cells are located in the area...

The oogenic germline starvation response in C. elegans.

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Hannah S Seidel

Full Text Available Many animals alter their reproductive strategies in response to environmental stress. Here we have investigated how L4 hermaphrodites of Caenorhabditis elegans respond to starvation. To induce starvation, we removed food at 2 h intervals from very early- to very late-stage L4 animals. The starved L4s molted into adulthood, initiated oogenesis, and began producing embryos; however, all three processes were severely delayed, and embryo viability was reduced. Most animals died via 'bagging,' because egg-laying was inhibited, and embryos hatched in utero, consuming their parent hermaphrodites from within. Some animals, however, avoided bagging and survived long term. Long-term survival did not rely on embryonic arrest but instead upon the failure of some animals to produce viable progeny during starvation. Regardless of the bagging fate, starved animals showed two major changes in germline morphology: All oogenic germlines were dramatically reduced in size, and these germlines formed only a single oocyte at a time, separated from the remainder of the germline by a tight constriction. Both changes in germline morphology were reversible: Upon re-feeding, the shrunken germlines regenerated, and multiple oocytes formed concurrently. The capacity for germline regeneration upon re-feeding was not limited to the small subset of animals that normally survive starvation: When bagging was prevented ectopically by par-2 RNAi, virtually all germlines still regenerated. In addition, germline shrinkage strongly correlated with oogenesis, suggesting that during starvation, germline shrinkage may provide material for oocyte production. Finally, germline shrinkage and regeneration did not depend upon crowding. Our study confirms previous findings that starvation uncouples germ cell proliferation from germline stem cell maintenance. Our study also suggests that when nutrients are limited, hermaphrodites scavenge material from their germlines to reproduce. We discuss

Asymmetric distribution of pl10 and bruno2, new members of a conserved core of early germline determinants in cephalochordates

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Simon eDailey

2016-01-01

Full Text Available Molecular fingerprinting of conserved germline and somatic ¨stemness¨ markers in different taxa have been key in defining the mechanism of germline specification (preformation or epigenesis, as well as expression domains of somatic progenitors. The distribution of molecular markers for primordial germ cells (PGCs, including vasa, nanos and piwil1, as well as Vasa antibody staining, support a determinative mechanism of germline specification in the cephalochordate Branchiostoma lanceolatum, similarly to other amphioxus species. pl10 and bruno2, but not bruno4/6, are also expressed in a pattern consistent with these other germline genes, adding to our repertoire of PGC markers in lancelets. Expression of nanos, vasa and the remaining markers (musashi, pufA, pufB, pumilio and piwil2 may define populations of putative somatic progenitors in the tailbud, the amphioxus posterior growth zone, or zones of proliferative activity. Finally, we also identify a novel expression domain for musashi, a classic neural stem cell marker, during notochord development in amphioxus. These results are discussed in the context of germline determination in other taxa, stem cell regulation and regenerative capacity in adult amphioxus.

Aging and insulin signaling differentially control normal and tumorous germline stem cells.

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Kao, Shih-Han; Tseng, Chen-Yuan; Wan, Chih-Ling; Su, Yu-Han; Hsieh, Chang-Che; Pi, Haiwei; Hsu, Hwei-Jan

2015-02-01

Aging influences stem cells, but the processes involved remain unclear. Insulin signaling, which controls cellular nutrient sensing and organismal aging, regulates the G2 phase of Drosophila female germ line stem cell (GSC) division cycle in response to diet; furthermore, this signaling pathway is attenuated with age. The role of insulin signaling in GSCs as organisms age, however, is also unclear. Here, we report that aging results in the accumulation of tumorous GSCs, accompanied by a decline in GSC number and proliferation rate. Intriguingly, GSC loss with age is hastened by either accelerating (through eliminating expression of Myt1, a cell cycle inhibitory regulator) or delaying (through mutation of insulin receptor (dinR) GSC division, implying that disrupted cell cycle progression and insulin signaling contribute to age-dependent GSC loss. As flies age, DNA damage accumulates in GSCs, and the S phase of the GSC cell cycle is prolonged. In addition, GSC tumors (which escape the normal stem cell regulatory microenvironment, known as the niche) still respond to aging in a similar manner to normal GSCs, suggesting that niche signals are not required for GSCs to sense or respond to aging. Finally, we show that GSCs from mated and unmated females behave similarly, indicating that female GSC-male communication does not affect GSCs with age. Our results indicate the differential effects of aging and diet mediated by insulin signaling on the stem cell division cycle, highlight the complexity of the regulation of stem cell aging, and describe a link between ovarian cancer and aging. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

Drosophila's contribution to stem cell research [v1; ref status: indexed, http://f1000r.es/5h7

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Gyanesh Singh

2015-06-01

Full Text Available The discovery of Drosophila stem cells with striking similarities to mammalian stem cells has brought new hope for stem cell research. A recent development 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.

Expression of germline markers in three species of amphioxus supports a preformation mechanism of germ cell development in cephalochordates

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2013-01-01

Background In a previous study, we showed that the cephalochordate amphioxus Branchiostoma floridae has localized maternal transcripts of conserved germ cell markers Vasa and Nanos in its early embryos. These results provided strong evidence to support a preformation mechanism for primordial germ cell (PGC) development in B. floridae. Results In this study, we further characterize the expression of B. floridae homologs of Piwi and Tudor, which play important roles in germline development in diverse metazoan animals. We show that maternal mRNA of one of the identified Piwi-like homologs, Bf-Piwil1, also colocalizes with Vasa in the vegetal germ plasm and has zygotic expression in both the putative PGCs and the tail bud, suggesting it may function in both germline and somatic stem cells. More interestingly, one Tudor family gene, Bf-Tdrd7, is only expressed maternally and colocalizes with Vasa in germ plasm, suggesting that it may function exclusively in germ cell specification. To evaluate the conservation of the preformation mechanism among amphioxus species, we further analyze Vasa, Nanos, Piwil1, and Tdrd7 expression in two Asian amphioxus species, B. belcheri and B. japonicum. Their maternal transcripts all localize in similar patterns to those seen in B. floridae. In addition, we labeled putative PGCs with Vasa antibody to trace their dynamic distribution in developing larvae. Conclusions We identify additional germ plasm components in amphioxus and demonstrate the molecular distinction between the putative germline stem cells and somatic stem cells. Moreover, our results suggest that preformation may be a conserved mechanism for PGC specification among Branchiostoma species. Our Vasa antibody staining results suggest that after the late neurula stage, amphioxus PGCs probably proliferate with the tail bud cells during posterior elongation and are deposited near the forming myomere boundaries. Subsequently, these PGCs would concentrate at the ventral tip of the

Stereotypical architecture of the stem cell niche is spatiotemporally established by miR-125-dependent coordination of Notch and steroid signaling.

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Yatsenko, Andriy S; Shcherbata, Halyna R

2018-02-08

Stem cell niches act as signaling platforms that regulate stem cell self-renewal and sustain stem cells throughout life; however, the specific developmental events controlling their assembly are not well understood. Here, we show that during Drosophila ovarian germline stem cell niche formation, the status of Notch signaling in the cell can be reprogrammed. This is controlled via steroid-induced miR-125 , which targets a negative regulator of Notch signaling, Tom. Thus, miR-125 acts as a spatiotemporal coordinator between paracrine Notch and endocrine steroid signaling. Moreover, a dual security mechanism for Notch signaling activation exists to ensure the robustness of niche assembly. Particularly, stem cell niche cells can be specified either via lateral inhibition, in which a niche cell precursor acquires Notch signal-sending status randomly, or via peripheral induction, whereby Delta is produced by a specific cell. When one mechanism is perturbed due to mutations, developmental defects or environmental stress, the remaining mechanism ensures that the niche is formed, perhaps abnormally, but still functional. This guarantees that the germline stem cells will have their residence, thereby securing progressive oogenesis and, thus, organism reproduction. © 2018. Published by The Company of Biologists Ltd.

C. elegans AMPKs promote survival and arrest germline development during nutrient stress

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Masamitsu Fukuyama

2012-08-01

Mechanisms controlling development, growth, and metabolism are coordinated in response to changes in environmental conditions, enhancing the likelihood of survival to reproductive maturity. Much remains to be learned about the molecular basis underlying environmental influences on these processes. C. elegans larvae enter a developmentally dormant state called L1 diapause when hatched into nutrient-poor conditions. The nematode pten homologue daf-18 is essential for maintenance of survival and germline stem cell quiescence during this period (Fukuyama et al., 2006; Sigmond et al., 2008, but the details of the signaling network(s in which it functions remain to be elucidated. Here, we report that animals lacking both aak-1 and aak-2, which encode the two catalytic α subunits of AMP-activated protein kinase (AMPK, show reduced viability and failure to maintain mitotic quiescence in germline stem cells during L1 diapause. Furthermore, failure to arrest germline proliferation has a long term consequence; aak double mutants that have experienced L1 diapause develop into sterile adults when returned to food, whereas their continuously fed siblings are fertile. Both aak and daf-18 appear to maintain germline quiescence by inhibiting activity of the common downstream target, TORC1 (TOR Complex 1. In contrast, rescue of the lethality phenotype indicates that aak-2 acts not only in the intestine, as does daf-18, but also in neurons, likely promoting survival by preventing energy deprivation during L1 diapause. These results not only provide evidence that AMPK contributes to survival during L1 diapause in a manner distinct from that by which it controls dauer diapause, but they also suggest that AMPK suppresses TORC1 activity to maintain stem cell quiescence.

Genome-wide RNAi Screen Identifies Networks Involved in Intestinal Stem Cell Regulation in Drosophila

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Xiankun Zeng

2015-02-01

Full Text Available The intestinal epithelium is the most rapidly self-renewing tissue in adult animals and maintained by intestinal stem cells (ISCs in both Drosophila and mammals. To comprehensively identify genes and pathways that regulate ISC fates, we performed a genome-wide transgenic RNAi screen in adult Drosophila intestine and identified 405 genes that regulate ISC maintenance and lineage-specific differentiation. By integrating these genes into publicly available interaction databases, we further developed functional networks that regulate ISC self-renewal, ISC proliferation, ISC maintenance of diploid status, ISC survival, ISC-to-enterocyte (EC lineage differentiation, and ISC-to-enteroendocrine (EE lineage differentiation. By comparing regulators among ISCs, female germline stem cells, and neural stem cells, we found that factors related to basic stem cell cellular processes are commonly required in all stem cells, and stem-cell-specific, niche-related signals are required only in the unique stem cell type. Our findings provide valuable insights into stem cell maintenance and lineage-specific differentiation.

AluY-mediated germline deletion, duplication and somatic stem cell reversion in UBE2T defines a new subtype of Fanconi anemia.

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Virts, Elizabeth L; Jankowska, Anna; Mackay, Craig; Glaas, Marcel F; Wiek, Constanze; Kelich, Stephanie L; Lottmann, Nadine; Kennedy, Felicia M; Marchal, Christophe; Lehnert, Erik; Scharf, Rüdiger E; Dufour, Carlo; Lanciotti, Marina; Farruggia, Piero; Santoro, Alessandra; Savasan, Süreyya; Scheckenbach, Kathrin; Schipper, Jörg; Wagenmann, Martin; Lewis, Todd; Leffak, Michael; Farlow, Janice L; Foroud, Tatiana M; Honisch, Ellen; Niederacher, Dieter; Chakraborty, Sujata C; Vance, Gail H; Pruss, Dmitry; Timms, Kirsten M; Lanchbury, Jerry S; Alpi, Arno F; Hanenberg, Helmut

2015-09-15

Fanconi anemia (FA) is a rare inherited disorder clinically characterized by congenital malformations, progressive bone marrow failure and cancer susceptibility. At the cellular level, FA is associated with hypersensitivity to DNA-crosslinking genotoxins. Eight of 17 known FA genes assemble the FA E3 ligase complex, which catalyzes monoubiquitination of FANCD2 and is essential for replicative DNA crosslink repair. Here, we identify the first FA patient with biallelic germline mutations in the ubiquitin E2 conjugase UBE2T. Both mutations were aluY-mediated: a paternal deletion and maternal duplication of exons 2-6. These loss-of-function mutations in UBE2T induced a cellular phenotype similar to biallelic defects in early FA genes with the absence of FANCD2 monoubiquitination. The maternal duplication produced a mutant mRNA that could encode a functional protein but was degraded by nonsense-mediated mRNA decay. In the patient's hematopoietic stem cells, the maternal allele with the duplication of exons 2-6 spontaneously reverted to a wild-type allele by monoallelic recombination at the duplicated aluY repeat, thereby preventing bone marrow failure. Analysis of germline DNA of 814 normal individuals and 850 breast cancer patients for deletion or duplication of UBE2T exons 2-6 identified the deletion in only two controls, suggesting aluY-mediated recombinations within the UBE2T locus are rare and not associated with an increased breast cancer risk. Finally, a loss-of-function germline mutation in UBE2T was detected in a high-risk breast cancer patient with wild-type BRCA1/2. Cumulatively, we identified UBE2T as a bona fide FA gene (FANCT) that also may be a rare cancer susceptibility gene. © The Author 2015. Published by Oxford University Press.

Generation of germ cells in vitro in the era of induced pluripotent stem cells.

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Imamura, Masanori; Hikabe, Orie; Lin, Zachary Yu-Ching; Okano, Hideyuki

2014-01-01

Induced pluripotent stem cells (iPSCs) are stem cells that can be artificially generated via "cellular reprogramming" using gene transduction in somatic cells. iPSCs have enormous potential in stem-cell biology as they can give rise to numerous cell lineages, including the three germ layers. An evaluation of germ-line competency by blastocyst injection or tetraploid complementation, however, is critical for determining the developmental potential of mouse iPSCs towards germ cells. Recent studies have demonstrated that primordial germ cells obtained by the in vitro differentiation of iPSCs produce functional gametes as well as healthy offspring. These findings illustrate not only that iPSCs are developmentally similar to embryonic stem cells (ESCs), but also that somatic cells from adult tissues can produce gametes in vitro, that is, if they are reprogrammed into iPSCs. In this review, we discuss past and recent advances in the in vitro differentiation of germ cells using pluripotent stem cells, with an emphasis on ESCs and iPSCs. While this field of research is still at a stage of infancy, it holds great promises for investigating the mechanisms of germ-cell development, especially in humans, and for advancing reproductive and developmental engineering technologies in the future. © 2013 Wiley Periodicals, Inc.

Cell cycle accumulation of the proliferating cell nuclear antigen PCN-1 transitions from continuous in the adult germline to intermittent in the early embryo of C. elegans.

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Kocsisova, Zuzana; Kornfeld, Kerry; Schedl, Tim

2018-05-30

The proliferating cell nuclear antigen (PCNA or PCN-1 in C. elegans), an essential processivity factor for DNA polymerase δ, has been widely used as a marker of S-phase. In C. elegans early embryos, PCN-1 accumulation is cyclic, localizing to the nucleus during S-phase and the cytoplasm during the rest of the cell cycle. The C. elegans larval and adult germline is an important model systems for studying cell cycle regulation, and it was observed that the cell cycle regulator cyclin E (CYE-1 in C. elegans) displays a non-cyclic, continuous accumulation pattern in this tissue. The accumulation pattern of PCN-1 has not been well defined in the larval and adult germline, and the objective of this study was to determine if the accumulation pattern is cyclic, as in other cells and organisms, or continuous, similar to cyclin E. To study the larval and adult germline accumulation of PCN-1 expressed from its native locus, we used CRISPR/Cas9 technology to engineer a novel allele of pcn-1 that encodes an epitope-tagged protein. S-phase nuclei were labeled using EdU nucleotide incorporation, and FLAG::PCN-1 was detected by antibody staining. All progenitor zone nuclei, including those that were not in S-phase (as they were negative for EdU staining) showed PCN-1 accumulation, indicating that PCN-1 accumulated during all cell cycle phases in the germline progenitor zone. The same result was observed with a GFP::PCN-1 fusion protein expressed from a transgene. pcn-1 loss-of-function mutations were analyzed, and pcn-1 was necessary for robust fertility and embryonic development. In the C. elegans early embryo as well as other organisms, PCN-1 accumulates in nuclei only during S-phase. By contrast, in the progenitor zone of the germline of C. elegans, PCN-1 accumulated in nuclei during all cell cycle stages. This pattern is similar to accumulation pattern of cyclin E. These observations support the model that mitotic cell cycle regulation in the germline stem and progenitor

Stem cell potency and the ability to contribute to chimeric organisms.

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Polejaeva, Irina; Mitalipov, Shoukhrat

2013-03-01

Mouse embryonic chimeras are a well-established tool for studying cell lineage commitment and pluripotency. Experimental chimeras were successfully produced by combining two or more preimplantation embryos or by introducing into host embryo cultured pluripotent embryonic stem cells (ESCs). Chimera production using genetically modified ESCs became the method of choice for the generation of knockout or knockin mice. Although the derivation of ESCs or ESC-like cells has been reported for other species, only mouse and rat pluripotent stem cells have been shown to contribute to germline-competent chimeras, which is the defining feature of ESCs. Herein, we describe different approaches employed for the generation of embryonic chimeras, define chimera-competent cell types, and describe cases of spontaneous chimerism in humans. We also review the current state of derivation of pluripotent stem cells in several species and discuss outcomes of various chimera studies when such cells are used.

The perfect host: a mouse host embryo facilitating more efficient germ line transmission of genetically modified embryonic stem cells.

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Robert A Taft

Full Text Available There is a continual need to improve efficiency in creating precise genetic modifications in mice using embryonic stem cells (ESCs. We describe a novel approach resulting in 100% germline transmission from competent injected ESCs. We developed an F1 mouse host embryo (Perfect Host, PH that selectively ablates its own germ cells via tissue-specific induction of diphtheria toxin. This approach allows competent microinjected ESCs to fully dominate the germline, eliminating competition for this critical niche in the developing and adult animal. This is in contrast to conventional methods, where competition from host germ cells results in offspring derived from host cells and ESCs, necessitating extensive breeding of chimeras and genotyping to identify germline. The germline transmission process is also complicated by variability in the actual number of ESCs that colonize the germline niche and the proportion that are germline competent. To validate the PH approach we used ESC lines derived from 129 F1, BALB/cByJ, and BTBR backgrounds as well as an iPS line. Resulting chimeric males produced 194 offspring, all paternally derived from the introduced stem cells, with no offspring being derived from the host genome. We further tested this approach using eleven genetically modified C57BL/6N ESC lines (International Knockout Mouse Consortium. ESC germline transmission was observed in 9/11 (82% lines using PH blastocysts, compared to 6/11 (55% when conventional host blastocysts were used. Furthermore, less than 35% (83/240 of mice born in the first litters from conventional chimeras were confirmed to be of ESC-origin. By comparison, 100% (137/137 of the first litter offspring of PH chimeras were confirmed as ESC-derived. Together, these data demonstrate that the PH approach increases the probability of germline transmission and speeds the generation of ESC derived animals from chimeras. Collectively, this approach reduces the time and costs inherent in the

From stem cell to embryo without centrioles.

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Stevens, Naomi R; Raposo, Alexandre A S F; Basto, Renata; St Johnston, Daniel; Raff, Jordan W

2007-09-04

Centrosome asymmetry plays a key role in ensuring the asymmetric division of Drosophila neural stem cells (neuroblasts [NBs]) and male germline stem cells (GSCs) [1-3]. In both cases, one centrosome is anchored close to a specific cortical region during interphase, thus defining the orientation of the spindle during the ensuing mitosis. To test whether asymmetric centrosome behavior is a general feature of stem cells, we have studied female GSCs, which divide asymmetrically, producing another GSC and a cystoblast. The cystoblast then divides and matures into an oocyte, a process in which centrosomes exhibit a series of complex behaviors proposed to play a crucial role in oogenesis [4-6]. We show that the interphase centrosome does not define spindle orientation in female GSCs and that DSas-4 mutant GSCs [7], lacking centrioles and centrosomes, invariably divide asymmetrically to produce cystoblasts that proceed normally through oogenesis-remarkably, oocyte specification, microtubule organization, and mRNA localization are all unperturbed. Mature oocytes can be fertilized, but embryos that cannot support centriole replication arrest very early in development. Thus, centrosomes are dispensable for oogenesis but essential for early embryogenesis. These results reveal that asymmetric centrosome behavior is not an essential feature of stem cell divisions.

Developmental expression of "germline"- and "sex determination"-related genes in the ctenophore Mnemiopsis leidyi.

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Reitzel, Adam M; Pang, Kevin; Martindale, Mark Q

2016-01-01

An essential developmental pathway in sexually reproducing animals is the specification of germ cells and the differentiation of mature gametes, sperm and oocytes. The "germline" genes vasa, nanos and piwi are commonly identified in primordial germ cells, suggesting a molecular signature for the germline throughout animals. However, these genes are also expressed in a diverse set of somatic stem cells throughout the animal kingdom leaving open significant questions for whether they are required for germline specification. Similarly, members of the Dmrt gene family are essential components regulating sex determination and differentiation in bilaterian animals, but the functions of these transcription factors, including potential roles in sex determination, in early diverging animals remain unknown. The phylogenetic position of ctenophores and the genome sequence of the lobate Mnemiopsis leidyi motivated us to determine the compliment of these gene families in this species and determine expression patterns during development. Our phylogenetic analyses of the vasa, piwi and nanos gene families show that Mnemiopsis has multiple genes in each family with multiple lineage-specific paralogs. Expression domains of Mnemiopsis nanos, vasa and piwi, during embryogenesis from fertilization to the cydippid stage, were diverse, with little overlapping expression and no or little expression in what we think are the germ cells or gametogenic regions. piwi paralogs in Mnemiopsis had distinct expression domains in the ectoderm during development. We observed overlapping expression domains in the apical organ and tentacle apparatus of the cydippid for a subset of "germline genes," which are areas of high cell proliferation, suggesting that these genes are involved with "stem cell" specification and maintenance. Similarly, the five Dmrt genes show diverse non-overlapping expression domains, with no clear evidence for expression in future gametogenic regions of the adult. We also

Whole-genome sequencing of spermatocytic tumors provides insights into the mutational processes operating in the male germline

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Giannoulatou, Eleni; Maher, Geoffrey J; Ding, Zhihao

2017-01-01

Adult male germline stem cells (spermatogonia) proliferate by mitosis and, after puberty, generate spermatocytes that undertake meiosis to produce haploid spermatozoa. Germ cells are under evolutionary constraint to curtail mutations and maintain genome integrity. Despite constant turnover...

SHIP1-expressing mesenchymal stem cells regulate hematopoietic stem cell homeostasis and lineage commitment during aging.

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Iyer, Sonia; Brooks, Robert; Gumbleton, Matthew; Kerr, William G

2015-05-01

Hematopoietic stem cell (HSC) self-renewal and lineage choice are subject to intrinsic control. However, this intrinsic regulation is also impacted by external cues provided by niche cells. There are multiple cellular components that participate in HSC support with the mesenchymal stem cell (MSC) playing a pivotal role. We had previously identified a role for SH2 domain-containing inositol 5'-phosphatase-1 (SHIP1) in HSC niche function through analysis of mice with germline or induced SHIP1 deficiency. In this study, we show that the HSC compartment expands significantly when aged in a niche that contains SHIP1-deficient MSC; however, this expanded HSC compartment exhibits a strong bias toward myeloid differentiation. In addition, we show that SHIP1 prevents chronic G-CSF production by the aging MSC compartment. These findings demonstrate that intracellular signaling by SHIP1 in MSC is critical for the control of HSC output and lineage commitment during aging. These studies increase our understanding of how myeloid bias occurs in aging and thus could have implications for the development of myeloproliferative disease in aging.

Functional genomic characterization of neoblast-like stem cells in larval Schistosoma mansoni

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Wang, Bo; Collins, James J; Newmark, Phillip A

2013-01-01

Schistosomes infect hundreds of millions of people in the developing world. Transmission of these parasites relies on a stem cell-driven, clonal expansion of larvae inside a molluscan intermediate host. How this novel asexual reproductive strategy relates to current models of stem cell maintenance and germline specification is unclear. Here, we demonstrate that this proliferative larval cell population (germinal cells) shares some molecular signatures with stem cells from diverse organisms, in particular neoblasts of planarians (free-living relatives of schistosomes). We identify two distinct germinal cell lineages that differ in their proliferation kinetics and expression of a nanos ortholog. We show that a vasa/PL10 homolog is required for proliferation and maintenance of both populations, whereas argonaute2 and a fibroblast growth factor receptor-encoding gene are required only for nanos-negative cells. Our results suggest that an ancient stem cell-based developmental program may have enabled the evolution of the complex life cycle of parasitic flatworms. DOI: http://dx.doi.org/10.7554/eLife.00768.001 PMID:23908765

Quantification of Crypt and Stem Cell Evolution in the Normal and Neoplastic Human Colon

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Ann-Marie Baker

2014-08-01

Full Text Available Human intestinal stem cell and crypt dynamics remain poorly characterized because transgenic lineage-tracing methods are impractical in humans. Here, we have circumvented this problem by quantitatively using somatic mtDNA mutations to trace clonal lineages. By analyzing clonal imprints on the walls of colonic crypts, we show that human intestinal stem cells conform to one-dimensional neutral drift dynamics with a “functional” stem cell number of five to six in both normal patients and individuals with familial adenomatous polyposis (germline APC−/+. Furthermore, we show that, in adenomatous crypts (APC−/−, there is a proportionate increase in both functional stem cell number and the loss/replacement rate. Finally, by analyzing fields of mtDNA mutant crypts, we show that a normal colon crypt divides around once every 30–40 years, and the division rate is increased in adenomas by at least an order of magnitude. These data provide in vivo quantification of human intestinal stem cell and crypt dynamics.

Ovarian Germline Stem Cells (OGSCs and the Hippo Signaling Pathway Association with Physiological and Pathological Ovarian Aging in Mice

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Jia Li

2015-07-01

Full Text Available Background: The Hippo signaling pathway plays fundamental roles in stem cell maintenance in a variety of tissues and has thus implications for stem cell biology. Key components of this recently discovered pathway have been shown to be associated with primordial follicle activation. However, whether the Hippo signaling pathway plays a role in the development of Ovarian Germline Stem Cells (OGSCs during physiological and pathological ovarian aging in mice is unknown. Methods: Mice at the age of 7 days (7D, or of 2, 10, or 20 months (2M, 10M, 20M and mice at 2M treated with TPT and CY/BUS drugs were selected as physiological and pathological ovarian aging models, respectively. Immunohistochemistry was used to assess the development of follicles, and the co-localization of genes characteristic of OGSCs with MST1, LATS2 and YAP1 was assessed by immunofluorescence, western blotting and real-time PCR methods. Results: The Hippo signal pathway and MVH/OCT4 genes were co-expressed in the mouse ovarian cortex. The level and co-localization of LATS2, MST1, MVH, and OCT4 were significantly decreased with increased age, but YAP1 was more prevalent in the mouse ovarian cortex of 2M mice than 7D mice and was not observed in 20M mice. Furthermore, YAP1, MVH, and OCT4 were gradually decreased after TPT and CY/BUS treatment, and LATS2 mRNA and protein up-regulation persisted in TPT- and CY/BUS-treated mice. However, the expression of MST1 was lower in the TPT and CY/BUS groups compared with the control group. In addition, pYAP1 protein showed the highest expression in the ovarian cortexes of 7D mice compared with 20M mice, and the value of pYAP1/YAP1 decreased from 7D to 20M. Moreover, pYAP1 decreased in the TPT- and CY/BUS-treated groups, but the value of pYAP1/YAP1 increased in these groups. Conclusion: Taken together, our results show that the Hippo signaling pathway is associated with the changes that take place in OGSCs during physiological and pathological

DNA asymmetry in stem cells - immortal or mortal?

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Yadlapalli, Swathi; Yamashita, Yukiko M

2013-09-15

The immortal strand hypothesis proposes that stem cells retain a template copy of genomic DNA (i.e. an 'immortal strand') to avoid replication-induced mutations. An alternative hypothesis suggests that certain cells segregate sister chromatids non-randomly to transmit distinct epigenetic information. However, this area of research has been highly controversial, with conflicting data even from the same cell types. Moreover, historically, the same term of 'non-random sister chromatid segregation' or 'biased sister chromatid segregation' has been used to indicate distinct biological processes, generating a confusion in the biological significance and potential mechanism of each phenomenon. Here, we discuss the models of non-random sister chromatid segregation, and we explore the strengths and limitations of the various techniques and experimental model systems used to study this question. We also describe our recent study on Drosophila male germline stem cells, where sister chromatids of X and Y chromosomes are segregated non-randomly during cell division. We aim to integrate the existing evidence to speculate on the underlying mechanisms and biological relevance of this long-standing observation on non-random sister chromatid segregation.

Pluripotent Conversion of Muscle Stem Cells Without Reprogramming Factors or Small Molecules.

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Bose, Bipasha; Shenoy P, Sudheer

2016-02-01

Muscle derived stem cells (MDSCs) are multipotent stem cells that can differentiate into several lineages including skeletal muscle precursor cells. Here, we show that MDSCs from myostatin null mice (Mstn (-/-) ) can be readily induced into pluripotent stem cells without using reprogramming factors. Microarray studies revealed a strong upregulation of markers like Leukemia Inhibitory factor (LIF) and Leukemia Inhibitory factor receptor (LIFR) in Mstn (-/-) MDSCs as compared to wild type MDSCs (WT-MDSCs). Furthermore when cultured in mouse embryonic stem cell media with LIF for 95 days, Mstn (-/-) MDSCs formed embryonic stem cell (ES) like colonies. We termed such ES like cells as the culture-induced pluripotent stem cells (CiPSC). CiPSCs from Mstn (-/-) MDSCs were phenotypically similar to ESCs, expressed high levels of Oct4, Nanog, Sox2 and SSEA-1, maintained a normal karyotype. Furthermore, CiPSCs formed embryoid bodies and teratomas when injected into immunocompromised mice. In addition, CiPSCs differentiated into somatic cells of all three lineages. We further show that culturing in ES cell media, resulted in hypermethylation and downregulation of BMP2 in Mstn(-/-) MDSCs. Western blot further confirmed a down regulation of BMP2 signaling in Mstn (-/-) MDSCs in supportive of pluripotent reprogramming. Given that down regulation of BMP2 has been shown to induce pluripotency in cells, we propose that lack of myostatin epigenetically reprograms the MDSCs to become pluripotent stem cells. Thus, here we report the successful establishment of ES-like cells from adult stem cells of the non-germline origin under culture-induced conditions without introducing reprogramming genes.

A vector-based system for the differentiation of mouse embryonic stem cells toward germ-line cells

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Reza Ebrahimzadeh-Vesal

2014-08-01

Conclusion: In this study, we demonstrated the in vitro generation of mouse embryonic stem cells to germ cells by using a backbone vector containing the fusion gene Stra8-EGFP. The Stra8 gene is a retinoic acid-responsive protein and is able to regulate meiotic initiation.

Progress, problems and prospects of porcine pluripotent stem cells

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Hanning WANG,Yangli PEI,Ning LI,Jianyong HAN

2014-02-01

Full Text Available Pluripotent stem cells (PSCs, including embryonic stem cells (ESCs and induced PSCs (iPSCs, can differentiate into cells of the three germ layers, suggesting that PSCs have great potential for basic developmental biology research and wide applications for clinical medicine. Genuine ESCs and iPSCs have been derived from mice and rats, but not from livestock such as the pig─an ideal animal model for studying human disease and regenerative medicine due to similarities with human physiologic processes. Efforts to derive porcine ESCs and iPSCs have not yielded high-quality PSCs that can produce chimeras with germline transmission. Thus, exploration of the unique porcine gene regulation network of preimplantation embryonic development may permit optimization of in vitro culture systems for raising porcine PSCs. Here we summarize the recent progress in porcine PSC generation as well as the problems encountered during this progress and we depict prospects for generating porcine naive PSCs.

Mouse embryonic stem cells efficiently lipofected with nuclear localization peptide result in a high yield of chimeric mice and retain germline transmission potency.

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Ma, Haiching; Liu, Qin; Diamond, Scott L; Pierce, Eric A

2004-06-01

Embryonic stem (ES) cells are an important tool in developmental biology, genomics, and transgenic methods, as well as in potential clinical applications such as gene therapy or tissue engineering. Electroporation is the standard transfection method for mouse ES (mES) cells because lipofection is quite inefficient. It is also unclear if mES cells treated with cationic lipids maintain pluripotency. We have developed a simple lipofection method for high efficiency transfection and stable transgene expression by employing the nonclassical nuclear localization signal M9 derived from the heterogeneous nuclear ribonucleoprotein A1. In contrast to using 20 microg DNA for 10 x 10(6) cells via electroporation which resulted in 10-20 positive cells/mm2, M9-assisted lipofection of 2 x 10(5) cells with 2 microg DNA resulted in > 150 positive cells/mm2. Electroporation produced only 0.16% EGFP positive cells with fluorescence intensity (FI) > 1000 by FACS assay, while M9-lipofection produced 36-fold more highly EGFP positive cells (5.75%) with FI > 1000. Using 2.5 x 10(6) ES cells and 6 microg linearized DNA followed by selection with G418, electroporation yielded 17 EGFP expressing colonies, while M9-assisted lipofection yielded 72 EGFP expressing colonies. The mES cells that stably expressed EGFP following M9-assisted lipofection yielded > 66% chimeric mice (8 of 12) and contributed efficiently to the germline. In an example of gene targeting, a knock-in mouse was produced from an ES clone screened from 200 G418-resistant colonies generated via M9-assisted lipofection. To our knowledge, this is the first report of generation of transgenic or knock-in mice obtained from lipofected mES cells and this method may facilitate large scale genomic studies of ES developmental biology or large scale generation of mouse models of human disease. Copyright 2003 Elsevier Inc.

Exploration of the Germline Genome of the Ciliate Chilodonella uncinata through Single-Cell Omics (Transcriptomics and Genomics

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Xyrus X. Maurer-Alcalá

2018-01-01

Full Text Available Separate germline and somatic genomes are found in numerous lineages across the eukaryotic tree of life, often separated into distinct tissues (e.g., in plants, animals, and fungi or distinct nuclei sharing a common cytoplasm (e.g., in ciliates and some foraminifera. In ciliates, germline-limited (i.e., micronuclear-specific DNA is eliminated during the development of a new somatic (i.e., macronuclear genome in a process that is tightly linked to large-scale genome rearrangements, such as deletions and reordering of protein-coding sequences. Most studies of germline genome architecture in ciliates have focused on the model ciliates Oxytricha trifallax, Paramecium tetraurelia, and Tetrahymena thermophila, for which the complete germline genome sequences are known. Outside of these model taxa, only a few dozen germline loci have been characterized from a limited number of cultivable species, which is likely due to difficulties in obtaining sufficient quantities of “purified” germline DNA in these taxa. Combining single-cell transcriptomics and genomics, we have overcome these limitations and provide the first insights into the structure of the germline genome of the ciliate Chilodonella uncinata, a member of the understudied class Phyllopharyngea. Our analyses reveal the following: (i large gene families contain a disproportionate number of genes from scrambled germline loci; (ii germline-soma boundaries in the germline genome are demarcated by substantial shifts in GC content; (iii single-cell omics techniques provide large-scale quality germline genome data with limited effort, at least for ciliates with extensively fragmented somatic genomes. Our approach provides an efficient means to understand better the evolution of genome rearrangements between germline and soma in ciliates.

Clerics urge ban on altering germline cells.

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Norman, C

1983-06-24

A resolution calling for a ban on genetic engineering of human reproductive cells has been signed by leaders of almost every major church group in the United States. Some of the religious leaders, while not certain that a total moratorium should be placed on altering germline cells, signed the statement in order to stimulate public debate on the issue. Legislation has recently been introduced in Congress to set up a committee to monitor genetic engineering and its human applications, but author Jeremy Rifkin, the impetus behind the church leaders' resolution, argues that such tampering threatens the gene pool and should be banned altogether.

Neural stem cells achieve and maintain pluripotency without feeder cells.

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Hyun Woo Choi

Full Text Available BACKGROUND: Differentiated cells can be reprogrammed into pluripotency by transduction of four defined transcription factors. Induced pluripotent stem cells (iPS cells are expected to be useful for regenerative medicine as well as basic research. Recently, the report showed that mouse embryonic fibroblasts (MEF cells are not essential for reprogramming. However, in using fibroblasts as donor cells for reprogramming, individual fibroblasts that had failed to reprogram could function as feeder cells. METHODOLOGY/PRINCIPAL FINDING: Here, we show that adult mouse neural stem cells (NSCs, which are not functional feeder cells, can be reprogrammed into iPS cells using defined four factors (Oct4, Sox2, Klf4, and c-Myc under feeder-free conditions. The iPS cells, generated from NSCs expressing the Oct4-GFP reporter gene, could proliferate for more than two months (passage 20. Generated and maintained without feeder cells, these iPS cells expressed pluripotency markers (Oct4 and Nanog, the promoter regions of Oct4 and Nanog were hypomethylated, could differentiated into to all three germ layers in vitro, and formed a germline chimera. These data indicate that NSCs can achieve and maintain pluripotency under feeder-free conditions. CONCLUSION/SIGNIFICANCE: This study suggested that factors secreted by feeder cells are not essential in the initial/early stages of reprogramming and for pluripotency maintenance. This technology might be useful for a human system, as a feeder-free reprogramming system may help generate iPS cells of a clinical grade for tissue or organ regeneration.

PRDM14 is expressed in germ cell tumors with constitutive overexpression altering human germline differentiation and proliferation

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Joanna J. Gell

2018-03-01

Full Text Available Germ cell tumors (GCTs are a heterogeneous group of tumors occurring in gonadal and extragonadal locations. GCTs are hypothesized to arise from primordial germ cells (PGCs, which fail to differentiate. One recently identified susceptibility loci for human GCT is PR (PRDI-BF1 and RIZ domain proteins 14 (PRDM14. PRDM14 is expressed in early primate PGCs and is repressed as PGCs differentiate. To examine PRDM14 in human GCTs we profiled human GCT cell lines and patient samples and discovered that PRDM14 is expressed in embryonal carcinoma cell lines, embryonal carcinomas, seminomas, intracranial germinomas and yolk sac tumors, but is not expressed in teratomas. To model constitutive overexpression in human PGCs, we generated PGC-like cells (PGCLCs from human pluripotent stem cells (PSCs and discovered that elevated expression of PRDM14 does not block early PGC formation. Instead, we show that elevated PRDM14 in PGCLCs causes proliferation and differentiation defects in the germline. Keywords: Germ cell tumor, PRDM14, Cell differentiation, Primordial germ cell, Proliferation

Lessons for Inductive Germline Determination

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Seervai, Riyad N.H.; Wessel, Gary M.

2015-01-01

SUMMARY Formation of the germline in an embryo marks a fresh round of reproductive potential, yet the developmental stage and location within the embryo where the primordial germ cells (PGCs) form differs wildly among species. In most animals, the germline is formed either by an inherited mechanism, in which maternal provisions within the oocyte drive localized germ-cell fate once acquired in the embryo, or an inductive mechanism that involves signaling between cells that directs germ-cell fate. The inherited mechanism has been widely studied in model organisms such as Drosophila melanogaster, Caenorhabditis elegans, Xenopus laevis, and Danio rerio. Given the rapid generation time and the effective adaptation for laboratory research of these organisms, it is not coincidental that research on these organisms has led the field in elucidating mechanisms for germline specification. The inductive mechanism, however, is less well understood and is studied primarily in the mouse (Mus musculus). In this review, we compare and contrast these two fundamental mechanisms for germline determination, beginning with the key molecular determinants that play a role in the formation of germ cells across all animal taxa. We next explore the current understanding of the inductive mechanism of germ-cell determination in mice, and evaluate the hypotheses for selective pressures on these contrasting mechanisms. We then discuss the hypothesis that the transition between these determination mechanisms, which has happened many times in phylogeny, is more of a continuum than a binary change. Finally, we propose an analogy between germline determination and sex determination in vertebrates—two of the milestones of reproduction and development—in which animals use contrasting strategies to activate similar pathways. PMID:23450642

Stem Cells

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

Involvement of plant stem cells or stem cell-like cells in dedifferentiation

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Fangwei eJiang

2015-11-01

Full Text Available 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.

Regulation of Injury-Induced Ovarian Regeneration by Activation of Oogonial Stem Cells.

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Erler, Piril; Sweeney, Alexandra; Monaghan, James R

2017-01-01

Some animals have the ability to generate large numbers of oocytes throughout life. This raises the question whether persistent adult germline stem cell populations drive continuous oogenesis and whether they are capable of mounting a regenerative response after injury. Here we demonstrate the presence of adult oogonial stem cells (OSCs) in the adult axolotl salamander ovary and show that ovarian injury induces OSC activation and functional regeneration of the ovaries to reproductive capability. Cells that have morphological similarities to germ cells were identified in the developing and adult ovaries via histological analysis. Genes involved in germ cell maintenance including Vasa, Oct4, Sox2, Nanog, Bmp15, Piwil1, Piwil2, Dazl, and Lhx8 were expressed in the presumptive OSCs. Colocalization of Vasa protein with H3 mitotic marker showed that both oogonial and spermatogonial adult stem cells were mitotically active. Providing evidence of stemness and viability of adult OSCs, enhanced green fluorescent protein (EGFP) adult OSCs grafted into white juvenile host gonads gave rise to EGFP OSCs, and oocytes. Last, the axolotl ovaries completely regenerated after partial ovariectomy injury. During regeneration, OSC activation resulted in rapid differentiation into new oocytes, which was demonstrated by Vasa + /BrdU + coexpression. Furthermore, follicle cell proliferation promoted follicle maturation during ovarian regeneration. Overall, these results show that adult oogenesis occurs via proliferation of endogenous OSCs in a tetrapod and mediates ovarian regeneration. This study lays the foundations to elucidate mechanisms of ovarian regeneration that will assist regenerative medicine in treating premature ovarian failure and reduced fertility. Stem Cells 2017;35:236-247. © 2016 AlphaMed Press.

Stem cells in dentistry--part I: stem cell sources.

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Egusa, Hiroshi; Sonoyama, Wataru; Nishimura, Masahiro; Atsuta, Ikiru; Akiyama, Kentaro

2012-07-01

Stem cells can self-renew and produce different cell types, thus providing new strategies to regenerate missing tissues and treat diseases. In the field of dentistry, adult mesenchymal stem/stromal cells (MSCs) have been identified in several oral and maxillofacial tissues, which suggests that the oral tissues are a rich source of stem cells, and oral stem and mucosal cells are expected to provide an ideal source for genetically reprogrammed cells such as induced pluripotent stem (iPS) cells. Furthermore, oral tissues are expected to be not only a source but also a therapeutic target for stem cells, as stem cell and tissue engineering therapies in dentistry continue to attract increasing clinical interest. Part I of this review outlines various types of intra- and extra-oral tissue-derived stem cells with regard to clinical availability and applications in dentistry. Additionally, appropriate sources of stem cells for regenerative dentistry are discussed with regard to differentiation capacity, accessibility and possible immunomodulatory properties. Copyright © 2012 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Elucidating the impact of neurofibromatosis-1 germline mutations on neurofibromin function and dopamine-based learning.

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Anastasaki, Corina; Woo, Albert S; Messiaen, Ludwine M; Gutmann, David H

2015-06-15

Neurofibromatosis type 1 (NF1) is a common autosomal dominant neurologic condition characterized by significant clinical heterogeneity, ranging from malignant cancers to cognitive deficits. Recent studies have begun to reveal rare genotype-phenotype correlations, suggesting that the specific germline NF1 gene mutation may be one factor underlying disease heterogeneity. The purpose of this study was to define the impact of the germline NF1 gene mutation on brain neurofibromin function relevant to learning. Herein, we employ human NF1-patient primary skin fibroblasts, induced pluripotent stem cells and derivative neural progenitor cells (NPCs) to demonstrate that NF1 germline mutations have dramatic effects on neurofibromin expression. Moreover, while all NF1-patient NPCs exhibit increased RAS activation and reduced cyclic AMP generation, there was a neurofibromin dose-dependent reduction in dopamine (DA) levels. Additionally, we leveraged two complementary Nf1 genetically-engineered mouse strains in which hippocampal-based learning and memory is DA-dependent to establish that neuronal DA levels and signaling as well as mouse spatial learning are controlled in an Nf1 gene dose-dependent manner. Collectively, this is the first demonstration that different germline NF1 gene mutations differentially dictate neurofibromin function in the brain. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Loss of DNA mismatch repair imparts a selective advantage in planarian adult stem cells.

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Jessica P Hollenbach

Full Text Available Lynch syndrome (LS leads to an increased risk of early-onset colorectal and other types of cancer and is caused by germline mutations in DNA mismatch repair (MMR genes. Loss of MMR function results in a mutator phenotype that likely underlies its role in tumorigenesis. However, loss of MMR also results in the elimination of a DNA damage-induced checkpoint/apoptosis activation barrier that may allow damaged cells to grow unchecked. A fundamental question is whether loss of MMR provides pre-cancerous stem cells an immediate selective advantage in addition to establishing a mutator phenotype. To test this hypothesis in an in vivo system, we utilized the planarian Schmidtea mediterranea which contains a significant population of identifiable adult stem cells. We identified a planarian homolog of human MSH2, a MMR gene which is mutated in 38% of LS cases. The planarian Smed-msh2 is expressed in stem cells and some progeny. We depleted Smed-msh2 mRNA levels by RNA-interference and found a striking survival advantage in these animals treated with a cytotoxic DNA alkylating agent compared to control animals. We demonstrated that this tolerance to DNA damage is due to the survival of mitotically active, MMR-deficient stem cells. Our results suggest that loss of MMR provides an in vivo survival advantage to the stem cell population in the presence of DNA damage that may have implications for tumorigenesis.

Genome Editing in Mouse Spermatogonial Stem Cell Lines Using TALEN and Double-Nicking CRISPR/Cas9

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Takuya Sato

2015-07-01

Full Text Available Mouse spermatogonial stem cells (SSCs can be cultured for multiplication and maintained for long periods while preserving their spermatogenic ability. Although the cultured SSCs, named germline stem (GS cells, are targets of genome modification, this process remains technically difficult. In the present study, we tested TALEN and double-nicking CRISPR/Cas9 on GS cells, targeting Rosa26 and Stra8 loci as representative genes dispensable and indispensable in spermatogenesis, respectively. Harvested GS cell colonies showed a high targeting efficiency with both TALEN and CRISPR/Cas9. The Rosa26-targeted GS cells differentiated into fertility-competent sperm following transplantation. On the other hand, Stra8-targeted GS cells showed defective spermatogenesis following transplantation, confirming its prime role in the initiation of meiosis. TALEN and CRISPR/Cas9, when applied in GS cells, will be valuable tools in the study of spermatogenesis and for revealing the genetic mechanism of spermatogenic failure.

Gastric stem cells and gastric cancer stem cells

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Han, Myoung-Eun; Oh, Sae-Ock

2013-01-01

The gastric epithelium is continuously regenerated by gastric stem cells, which give rise to various kinds of daughter cells, including parietal cells, chief cells, surface mucous cells, mucous neck cells, and enteroendocrine cells. The self-renewal and differentiation of gastric stem cells need delicate regulation to maintain the normal physiology of the stomach. Recently, it was hypothesized that cancer stem cells drive the cancer growth and metastasis. In contrast to conventional clonal ev...

Germline mutations in lysine specific demethylase 1 (LSD1/KDM1A) confer susceptibility to multiple myeloma.

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Wei, Xiaomu; Calvo-Vidal, M Nieves; Chen, Siwei; Wu, Gang; Revuelta, Maria V; Sun, Jian; Zhang, Jinghui; Walsh, Michael F; Nichols, Kim E; Joseph, Vijai; Snyder, Carrie; Vachon, Celine M; McKay, James D; Wang, Shu-Ping; Jayabalan, David S; Jacobs, Lauren M; Becirovic, Dina; Waller, Rosalie G; Artomov, Mykyta; Viale, Agnes; Patel, Jayeshkumar; Phillip, Jude M; Chen-Kiang, Selina; Curtin, Karen; Salama, Mohamed; Atanackovic, Djordje; Niesvizky, Ruben; Landgren, Ola; Slager, Susan L; Godley, Lucy A; Churpek, Jane; Garber, Judy E; Anderson, Kenneth C; Daly, Mark J; Roeder, Robert G; Dumontet, Charles; Lynch, Henry T; Mullighan, Charles G; Camp, Nicola J; Offit, Kenneth; Klein, Robert J; Yu, Haiyuan; Cerchietti, Leandro; Lipkin, Steven M

2018-03-20

Given the frequent and largely incurable occurrence of multiple myeloma (MM), identification of germline genetic mutations that predispose cells to MM may provide insight into disease etiology and the developmental mechanisms of its cell of origin, the plasma cell. Here we identified familial and early-onset MM kindreds with truncating mutations in lysine-specific demethylase 1 (LSD1/KDM1A), an epigenetic transcriptional repressor that primarily demethylates histone H3 on lysine 4 and regulates hematopoietic stem cell self-renewal. Additionally, we found higher rates of germline truncating and predicted deleterious missense KDM1A mutations in MM patients unselected for family history compared to controls. Both monoclonal gammopathy of unknown significance (MGUS) and MM cells have significantly lower KDM1A transcript levels compared with normal plasma cells. Transcriptome analysis of MM cells from KDM1A mutation carriers shows enrichment of pathways and MYC target genes previously associated with myeloma pathogenesis. In mice, antigen challenge followed by pharmacological inhibition of KDM1A promoted plasma cell expansion, enhanced secondary immune response, elicited appearance of serum paraprotein, and mediated upregulation of MYC transcriptional targets. These changes are consistent with the development of MGUS. Collectively, our findings show KDM1A is the first autosomal dominant MM germline predisposition gene, providing new insights into its mechanistic roles as a tumor suppressor during post-germinal center B cell differentiation. Copyright ©2018, American Association for Cancer Research.

Therapeutic opportunities: Telomere maintenance in inducible pluripotent stem cells

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Gourronc, Francoise A. [Department of Microbiology, University of Iowa (United States); Klingelhutz, Aloysius J., E-mail: al-klingelhutz@uiowa.edu [Department of Microbiology, University of Iowa (United States)

2012-02-01

It has been demonstrated that exogenous expression of a combination of transcription factors can reprogram differentiated cells such as fibroblasts and keratinocytes into what have been termed induced pluripotent stem (iPS) cells. These iPS cells are capable of differentiating into all the tissue lineages when placed in the right environment and, in the case of mouse cells, can generate chimeric mice and be transmitted through the germline. Safer and more efficient methods of reprogramming are rapidly being developed. Clearly, iPS cells present a number of exciting possibilities, including disease modeling and therapy. A major question is whether the nuclei of iPS cells are truly rejuvenated or whether they might retain some of the marks of aging from the cells from which they were derived. One measure of cellular aging is the telomere. In this regard, recent studies have demonstrated that telomeres in iPS cells may be rejuvenated. They are not only elongated by reactivated telomerase but they are also epigenetically modified to be similar but not identical to embryonic stem cells. Upon differentiation, the derivative cells turn down telomerase, the telomeres begin to shorten again, and the telomeres and the genome are returned to an epigenetic state that is similar to normal differentiated somatic cells. While these preliminary telomere findings are promising, the overall genomic integrity of reprogrammed cells may still be problematic and further studies are needed to examine the safety and feasibility of using iPS cells in regenerative medicine applications.

Therapeutic opportunities: Telomere maintenance in inducible pluripotent stem cells

International Nuclear Information System (INIS)

Gourronc, Francoise A.; Klingelhutz, Aloysius J.

2012-01-01

It has been demonstrated that exogenous expression of a combination of transcription factors can reprogram differentiated cells such as fibroblasts and keratinocytes into what have been termed induced pluripotent stem (iPS) cells. These iPS cells are capable of differentiating into all the tissue lineages when placed in the right environment and, in the case of mouse cells, can generate chimeric mice and be transmitted through the germline. Safer and more efficient methods of reprogramming are rapidly being developed. Clearly, iPS cells present a number of exciting possibilities, including disease modeling and therapy. A major question is whether the nuclei of iPS cells are truly rejuvenated or whether they might retain some of the marks of aging from the cells from which they were derived. One measure of cellular aging is the telomere. In this regard, recent studies have demonstrated that telomeres in iPS cells may be rejuvenated. They are not only elongated by reactivated telomerase but they are also epigenetically modified to be similar but not identical to embryonic stem cells. Upon differentiation, the derivative cells turn down telomerase, the telomeres begin to shorten again, and the telomeres and the genome are returned to an epigenetic state that is similar to normal differentiated somatic cells. While these preliminary telomere findings are promising, the overall genomic integrity of reprogrammed cells may still be problematic and further studies are needed to examine the safety and feasibility of using iPS cells in regenerative medicine applications.

Sex chromosomes and germline transcriptomics explored by single-cell sequencing and RNA-tomography

NARCIS (Netherlands)

Vértesy, Ábel

2018-01-01

In our study of germ cell differentiation, we applied two recently developed technologies on the germline of various model organisms: single-cell mRNA sequencing and RNA-tomography. For the first time we could look at gene expression with such a high resolution, and this led us to discover the

Small hypoxia-primed mesenchymal stem cells attenuate graft-versus-host disease

KAUST Repository

Kim, YongHwan

2018-05-22

Mesenchymal stem cells (MSCs) are of particular interest for the treatment of immune-related diseases due to their immunosuppressive capacity. Here, we show that Small MSCs primed with Hypoxia and Calcium ions (SHC-MSCs) exhibit enhanced stemness and immunomodulatory functions for treating allogeneic conflicts. Compared with naïve cultured human umbilical cord blood-derived MSCs, SHC-MSCs were resistant to passage-dependent senescence mediated via the monocyte chemoattractant protein-1 and p53/p21 cascade and secreted large amounts of pro-angiogenic and immunomodulatory factors, resulting in suppression of T-cell proliferation. SHC-MSCs showed DNA demethylation in pluripotency, germline, and imprinted genes similarly to very small embryonic-like stem cells, suggesting a potential mutual relationship. Genome-wide DNA methylome and transcriptome analyses indicated that genes related to immune modulation, cell adhesion, and the cell cycle were up-regulated in SHC-MSCs. Particularly, polo-like kinase-1 (PLK1), zinc-finger protein-143, dehydrogenase/reductase-3, and friend-of-GATA2 play a key role in the beneficial effects of SHC-MSCs. Administration of SHC-MSCs or PLK1-overexpressing MSCs significantly ameliorated symptoms of graft-versus-host disease (GVHD) in a humanized mouse model, resulting in significantly improved survival, less weight loss, and reduced histopathologic injuries in GVHD target organs compared with naïve MSC-infused mice. Collectively, our findings suggest that SHC-MSCs can improve the clinical treatment of allogeneic conflicts, including GVHD.

Effect of Antioxidants and Apoptosis Inhibitors on Cryopreservation of Murine Germ Cells Enriched for Spermatogonial Stem Cells.

Directory of Open Access Journals (Sweden)

Seung-Jung Ha

Full Text Available Spermatogonial stem cells (SSCs are germline stem cells that serve as the foundation of spermatogenesis to maintain fertility throughout a male's lifetime. To treat male infertility using stem cell banking systems and transplantation, it is important to be able to preserve SSCs for long periods of time. Therefore, this study was conducted to develop an optimal cryopreservation protocol for SSCs using antioxidants and apoptosis inhibitors in freezing medium. No differences were observed compared to controls when SSCs were cryopreserved in the presence of apoptosis inhibitors by themselves. However, mouse germ cells cryopreserved in basal medium containing the antioxidant hypotaurine (14 mM resulted in significantly greater proliferation potential and mitochondrial activity. Furthermore, treatment groups with combinations containing 200 mM trehalose and 14 mM hypotaurine showed higher proliferation rates compared to controls. In addition, several serum free conditions were evaluated for SSC cryopreservation. Treatment media containing 10% or 20% knockout serum replacement resulted in similar cryopreservation results compared to media containing FBS. SSC transplantation was also performed to confirm the functionality of SSCs frozen in 14 mM hypotaurine. Donor SSCs formed normal spermatogenic colonies and sperm in the recipient testis. These data indicate that inclusion of 14 mM hypotaurine in cryopreservation media is an effective way to efficiently cryopreserve germ cells enriched for SSCs and that knockout serum replacement can replace FBS in germ cell cryopreservation media.

Types of Stem Cells

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... Stem Cell Glossary Search Toggle Nav Types of Stem Cells Stem cells are the foundation from which all ... Learn About Stem Cells > Types of Stem Cells Stem cells Stem cells are the foundation for every organ ...

Stem cells

NARCIS (Netherlands)

Jukes, Jojanneke; Both, Sanne; Post, Janine; van Blitterswijk, Clemens; Karperien, Marcel; de Boer, Jan; van Blitterswijk, Clemens A.

2008-01-01

This chapter defines stem cells and their properties. It identifies the major differences between embryonic and adult stem cells. Stem cells can be defined by two properties: the ability to make identical copies of themselves and the ability to form other cell types of the body. These properties are

The protein kinase MBK-1 contributes to lifespan extension in daf-2 mutant and germline-deficient Caenorhabditis elegans.

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Mack, Hildegard I D; Zhang, Peichuan; Fonslow, Bryan R; Yates, John R

2017-05-25

In Caenorhabditis elegans , reduction of insulin/IGF-1 like signaling and loss of germline stem cells both increase lifespan by activating the conserved transcription factor DAF-16 (FOXO). While the mechanisms that regulate DAF-16 nuclear localization in response to insulin/IGF-1 like signaling are well characterized, the molecular pathways that act in parallel to regulate DAF-16 transcriptional activity, and the pathways that couple DAF-16 activity to germline status, are not fully understood at present. Here, we report that inactivation of MBK-1, the C. elegans ortholog of the human FOXO1-kinase DYRK1A substantially shortens the prolonged lifespan of daf-2 and glp-1 mutant animals while decreasing wild-type lifespan to a lesser extent. On the other hand, lifespan-reduction by mutation of the MBK-1-related kinase HPK-1 was not preferential for long-lived mutants. Interestingly, mbk-1 loss still allowed for DAF-16 nuclear accumulation but reduced expression of certain DAF-16 target genes in germline-less, but not in daf-2 mutant animals. These findings indicate that mbk-1 and daf-16 functionally interact in the germline- but not in the daf-2 pathway. Together, our data suggest mbk-1 as a novel regulator of C. elegans longevity upon both, germline ablation and DAF-2 inhibition, and provide evidence for mbk-1 regulating DAF-16 activity in germline-deficient animals.

Mei-p26 cooperates with Bam, Bgcn and Sxl to promote early germline development in the Drosophila ovary.

Directory of Open Access Journals (Sweden)

Yun Li

Full Text Available In the Drosophila female germline, spatially and temporally specific translation of mRNAs governs both stem cell maintenance and the differentiation of their progeny. However, the mechanisms that control and coordinate different modes of translational repression within this lineage remain incompletely understood. Here we present data showing that Mei-P26 associates with Bam, Bgcn and Sxl and nanos mRNA during early cyst development, suggesting that this protein helps to repress the translation of nanos mRNA. Together with recently published studies, these data suggest that Mei-P26 mediates both GSC self-renewal and germline differentiation through distinct modes of translational repression depending on the presence of Bam.

Mei-P26 Cooperates with Bam, Bgcn and Sxl to Promote Early Germline Development in the Drosophila Ovary

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Li, Yun; Zhang, Qiao; Carreira-Rosario, Arnaldo; Maines, Jean Z.; McKearin, Dennis M.; Buszczak, Michael

2013-01-01

In the Drosophila female germline, spatially and temporally specific translation of mRNAs governs both stem cell maintenance and the differentiation of their progeny. However, the mechanisms that control and coordinate different modes of translational repression within this lineage remain incompletely understood. Here we present data showing that Mei-P26 associates with Bam, Bgcn and Sxl and nanos mRNA during early cyst development, suggesting that this protein helps to repress the translation of nanos mRNA. Together with recently published studies, these data suggest that Mei-P26 mediates both GSC self-renewal and germline differentiation through distinct modes of translational repression depending on the presence of Bam. PMID:23526974

Aging, metabolism and stem cells: Spotlight on muscle stem cells.

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García-Prat, Laura; Muñoz-Cánoves, Pura

2017-04-15

All tissues and organs undergo a progressive regenerative decline as they age. This decline has been mainly attributed to loss of stem cell number and/or function, and both stem cell-intrinsic changes and alterations in local niches and/or systemic environment over time are known to contribute to the stem cell aging phenotype. Advancing in the molecular understanding of the deterioration of stem cell cells with aging is key for targeting the specific causes of tissue regenerative dysfunction at advanced stages of life. Here, we revise exciting recent findings on why stem cells age and the consequences on tissue regeneration, with a special focus on regeneration of skeletal muscle. We also highlight newly identified common molecular pathways affecting diverse types of aging stem cells, such as altered proteostasis, metabolism, or senescence entry, and discuss the questions raised by these findings. Finally, we comment on emerging stem cell rejuvenation strategies, principally emanating from studies on muscle stem cells, which will surely burst tissue regeneration research for future benefit of the increasing human aging population. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Stem cell biobanks.

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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.

Stem Cell Basics

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... Tips Info Center Research Topics Federal Policy Glossary Stem Cell Information General Information Clinical Trials Funding Information Current ... Basics » Stem Cell Basics I. Back to top Stem Cell Basics I. Introduction: What are stem cells, and ...

DDX4 (DEAD box polypeptide 4) colocalizes with cancer stem cell marker CD133 in ovarian cancers

International Nuclear Information System (INIS)

Kim, Ki Hyung; Kang, Yun-Jeong; Jo, Jin-Ok; Ock, Mee Sun; Moon, Soo Hyun; Suh, Dong Soo; Yoon, Man Soo; Park, Eun-Sil; Jeong, Namkung; Eo, Wan-Kyu; Kim, Heung Yeol; Cha, Hee-Jae

2014-01-01

Highlights: • Germ cell marker DDX4 was significantly increased in ovarian cancer. • Ovarian cancer stem cell marker CD133 was significantly increased in ovarian cancer. • DDX4 and CD133 were mostly colocalized in various types of ovarian cancer tissues. • CD133 positive ovarian cancer cells also express DDX4 whereas CD133-negative cells did not possess DDX4. • Germ cell marker DDX4 has the potential of ovarian cancer stem cell marker. - Abstract: DDX4 (DEAD box polypeptide 4), characterized by the conserved motif Asp-Glu-Ala-Asp (DEAD), is an RNA helicase which is implicated in various cellular processes involving the alteration of RNA secondary structure, such as translation initiation, nuclear and mitochondrial splicing, and ribosome and spliceosome assembly. DDX4 is known to be a germ cell-specific protein and is used as a sorting marker of germline stem cells for the production of oocytes. A recent report about DDX4 in ovarian cancer showed that DDX4 is overexpressed in epithelial ovarian cancer and disrupts a DNA damage-induced G2 checkpoint. We investigated the relationship between DDX4 and ovarian cancer stem cells by analyzing the expression patterns of DDX4 and the cancer stem cell marker CD133 in ovarian cancers via tissue microarray. Both DDX4 and CD133 were significantly increased in ovarian cancer compared to benign tumors, and showed similar patterns of expression. In addition, DDX4 and CD133 were mostly colocalized in various types of ovarian cancer tissues. Furthermore, almost all CD133 positive ovarian cancer cells also express DDX4 whereas CD133-negative cells did not possess DDX4, suggesting a strong possibility that DDX4 plays an important role in cancer stem cells, and/or can be used as an ovarian cancer stem cell marker

Long-term culture of chicken primordial germ cells isolated from embryonic blood and production of germline chimaeric chickens.

Science.gov (United States)

Naito, Mitsuru; Harumi, Takashi; Kuwana, Takashi

2015-02-01

Production of germline chimaeric chickens by the transfer of cultured primordial germ cells (PGC) is a useful system for germline manipulation. A novel culture system was developed for chicken PGC isolated from embryonic blood. The isolated PGC were cultured on feeder cells derived from chicken embryonic fibroblast. The cultured PGC formed colonies and they proliferated about 300-times during the first 30 days. The cultured PGC retained the ability to migrate to recipient gonads and were also chicken VASA homologue (CVH)-positive. Female PGC were present in the mixed-sex PGC populations cultured for more than 90 days and gave rise to viable offspring efficiently via germline chimaeric chickens. Male cultured PGC were transferred to recipient embryos and produced putative chimaeric chickens. The DNA derived from the cultured PGC was detected in the sperm samples of male putative chimaeric chickens, but no donor derived offspring were obtained. Donor-derived offspring were also obtained from germline chimaeric chickens by the transfer of frozen-thawed cultured PGC. The culture method for PGC developed in the present study is useful for manipulation of the germline in chickens, such as preservation of genetic resources and gene transfer. Copyright © 2014 Elsevier B.V. All rights reserved.

Haematopoietic stem and progenitor cells from human pluripotent stem cells

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Sugimura, Ryohichi; Jha, Deepak Kumar; Han, Areum; Soria-Valles, Clara; da Rocha, Edroaldo Lummertz; Lu, Yi-Fen; Goettel, Jeremy A.; Serrao, Erik; Rowe, R. Grant; Malleshaiah, Mohan; Wong, Irene; Sousa, Patricia; Zhu, Ted N.; Ditadi, Andrea; Keller, Gordon; Engelman, Alan N.; Snapper, Scott B.; Doulatov, Sergei; Daley, George Q.

2018-01-01

A variety of tissue lineages can be differentiated from pluripotent stem cells by mimicking embryonic development through stepwise exposure to morphogens, or by conversion of one differentiated cell type into another by enforced expression of master transcription factors. Here, to yield functional human haematopoietic stem cells, we perform morphogen-directed differentiation of human pluripotent stem cells into haemogenic endothelium followed by screening of 26 candidate haematopoietic stem-cell-specifying transcription factors for their capacity to promote multi-lineage haematopoietic engraftment in mouse hosts. We recover seven transcription factors (ERG, HOXA5, HOXA9, HOXA10, LCOR, RUNX1 and SPI1) that are sufficient to convert haemogenic endothelium into haematopoietic stem and progenitor cells that engraft myeloid, B and T cells in primary and secondary mouse recipients. Our combined approach of morphogen-driven differentiation and transcription-factor-mediated cell fate conversion produces haematopoietic stem and progenitor cells from pluripotent stem cells and holds promise for modelling haematopoietic disease in humanized mice and for therapeutic strategies in genetic blood disorders. PMID:28514439

Limbal Stem Cell Deficiency and Treatment with Stem Cell Transplantation.

Science.gov (United States)

Barut Selver, Özlem; Yağcı, Ayşe; Eğrilmez, Sait; Gürdal, Mehmet; Palamar, Melis; Çavuşoğlu, Türker; Ateş, Utku; Veral, Ali; Güven, Çağrı; Wolosin, Jose Mario

2017-10-01

The cornea is the outermost tissue of the eye and it must be transparent for the maintenance of good visual function. The superficial epithelium of the cornea, which is renewed continuously by corneal stem cells, plays a critical role in the permanence of this transparency. These stem cells are localized at the cornea-conjunctival transition zone, referred to as the limbus. When this zone is affected/destroyed, limbal stem cell deficiency ensues. Loss of limbal stem cell function allows colonization of the corneal surface by conjunctival epithelium. Over 6 million people worldwide are affected by corneal blindness, and limbal stem cell deficiency is one of the main causes. Fortunately, it is becoming possible to recover vision by autologous transplantation of limbal cells obtained from the contralateral eye in unilateral cases. Due to the potential risks to the donor eye, only a small amount of tissue can be obtained, in which only 1-2% of the limbal epithelial cells are actually limbal stem cells. Vigorous attempts are being made to expand limbal stem cells in culture to preserve or even enrich the stem cell population. Ex vivo expanded limbal stem cell treatment in limbal stem cell deficiency was first reported in 1997. In the 20 years since, various protocols have been developed for the cultivation of limbal epithelial cells. It is still not clear which method promotes effective stem cell viability and this remains a subject of ongoing research. The most preferred technique for limbal cell culture is the explant culture model. In this approach, a small donor eye limbal biopsy is placed as an explant onto a biocompatible substrate (preferably human amniotic membrane) for expansion. The outgrowth (cultivated limbal epithelial cells) is then surgically transferred to the recipient eye. Due to changing regulations concerning cell-based therapy, the implementation of cultivated limbal epithelial transplantation in accordance with Good Laboratory Practice using

Loss of Folliculin Disrupts Hematopoietic Stem Cell Quiescence and Homeostasis Resulting in Bone Marrow Failure.

Science.gov (United States)

Baba, Masaya; Toyama, Hirofumi; Sun, Lei; Takubo, Keiyo; Suh, Hyung-Chan; Hasumi, Hisashi; Nakamura-Ishizu, Ayako; Hasumi, Yukiko; Klarmann, Kimberly D; Nakagata, Naomi; Schmidt, Laura S; Linehan, W Marston; Suda, Toshio; Keller, Jonathan R

2016-04-01

Folliculin (FLCN) is an autosomal dominant tumor suppressor gene that modulates diverse signaling pathways required for growth, proliferation, metabolism, survival, motility, and adhesion. FLCN is an essential protein required for murine embryonic development, embryonic stem cell (ESC) commitment, and Drosophila germline stem cell maintenance, suggesting that Flcn may be required for adult stem cell homeostasis. Conditional inactivation of Flcn in adult hematopoietic stem/progenitor cells (HSPCs) drives hematopoietic stem cells (HSC) into proliferative exhaustion resulting in the rapid depletion of HSPC, loss of all hematopoietic cell lineages, acute bone marrow (BM) failure, and mortality after 40 days. HSC that lack Flcn fail to reconstitute the hematopoietic compartment in recipient mice, demonstrating a cell-autonomous requirement for Flcn in HSC maintenance. BM cells showed increased phosphorylation of Akt and mTorc1, and extramedullary hematopoiesis was significantly reduced by treating mice with rapamycin in vivo, suggesting that the mTorc1 pathway was activated by loss of Flcn expression in hematopoietic cells in vivo. Tfe3 was activated and preferentially localized to the nucleus of Flcn knockout (KO) HSPCs. Tfe3 overexpression in HSPCs impaired long-term hematopoietic reconstitution in vivo, recapitulating the Flcn KO phenotype, and supporting the notion that abnormal activation of Tfe3 contributes to the Flcn KO phenotype. Flcn KO mice develop an acute histiocytic hyperplasia in multiple organs, suggesting a novel function for Flcn in macrophage development. Thus, Flcn is intrinsically required to maintain adult HSC quiescence and homeostasis, and Flcn loss leads to BM failure and mortality in mice. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.

Learn About Stem Cells

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... Patient Handbook Stem Cell Glossary Search Toggle Nav Stem Cell Basics Stem cells are the foundation from which ... original cell’s DNA, cytoplasm and cell membrane. About stem cells Stem cells are the foundation of development in ...

Fake news portrayals of stem cells and stem cell research.

Science.gov (United States)

Marcon, Alessandro R; Murdoch, Blake; Caulfield, Timothy

2017-10-01

This study examines how stem cells and stem cell research are portrayed on websites deemed to be purveyors of distorted and dubious information. Content analysis was conducted on 224 articles from 2015 to 2016, compiled by searching with the keywords 'stem cell(s)' on a list of websites flagged for containing either 'fake' or 'junk science' news. Articles contained various exaggerated positive and negative claims about stem cells and stem cell science, health and science related conspiracy theories, and statements promoting fear and mistrust of conventional medicine. Findings demonstrate the existence of organized misinformation networks, which may lead the public away from accurate information and facilitate a polarization of public discourse.

Muscle Stem Cells: A Model System for Adult Stem Cell Biology.

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Cornelison, Ddw; Perdiguero, Eusebio

2017-01-01

Skeletal muscle stem cells, originally termed satellite cells for their position adjacent to differentiated muscle fibers, are absolutely required for the process of skeletal muscle repair and regeneration. In the last decade, satellite cells have become one of the most studied adult stem cell systems and have emerged as a standard model not only in the field of stem cell-driven tissue regeneration but also in stem cell dysfunction and aging. Here, we provide background in the field and discuss recent advances in our understanding of muscle stem cell function and dysfunction, particularly in the case of aging, and the potential involvement of muscle stem cells in genetic diseases such as the muscular dystrophies.

Stem Cell Pathology.

Science.gov (United States)

Fu, Dah-Jiun; Miller, Andrew D; Southard, Teresa L; Flesken-Nikitin, Andrea; Ellenson, Lora H; Nikitin, Alexander Yu

2018-01-24

Rapid advances in stem cell biology and regenerative medicine have opened new opportunities for better understanding disease pathogenesis and the development of new diagnostic, prognostic, and treatment approaches. Many stem cell niches are well defined anatomically, thereby allowing their routine pathological evaluation during disease initiation and progression. Evaluation of the consequences of genetic manipulations in stem cells and investigation of the roles of stem cells in regenerative medicine and pathogenesis of various diseases such as cancer require significant expertise in pathology for accurate interpretation of novel findings. Therefore, there is an urgent need for developing stem cell pathology as a discipline to facilitate stem cell research and regenerative medicine. This review provides examples of anatomically defined niches suitable for evaluation by diagnostic pathologists, describes neoplastic lesions associated with them, and discusses further directions of stem cell pathology.

Stem cell autotomy and niche interaction in different systems.

Science.gov (United States)

Dorn, David C; Dorn, August

2015-07-26

The best known cases of cell autotomy are the formation of erythrocytes and thrombocytes (platelets) from progenitor cells that reside in special niches. Recently, autotomy of stem cells and its enigmatic interaction with the niche has been reported from male germline stem cells (GSCs) in several insect species. First described in lepidopterans, the silkmoth, followed by the gipsy moth and consecutively in hemipterans, foremost the milkweed bug. In both, moths and the milkweed bug, GSCs form finger-like projections toward the niche, the apical cells (homologs of the hub cells in Drosophila). Whereas in the milkweed bug the projection terminals remain at the surface of the niche cells, in the gipsy moth they protrude deeply into the singular niche cell. In both cases, the projections undergo serial retrograde fragmentation with progressing signs of autophagy. In the gipsy moth, the autotomized vesicles are phagocytized and digested by the niche cell. In the milkweed bug the autotomized vesicles accumulate at the niche surface and disintegrate. Autotomy and sprouting of new projections appears to occur continuously. The significance of the GSC-niche interactions, however, remains enigmatic. Our concept on the signaling relationship between stem cell-niche in general and GSC and niche (hub cells and cyst stem cells) in particular has been greatly shaped by Drosophila melanogaster. In comparing the interactions of GSCs with their niche in Drosophila with those in species exhibiting GSC autotomy it is obvious that additional or alternative modes of stem cell-niche communication exist. Thus, essential signaling pathways, including niche-stem cell adhesion (E-cadherin) and the direction of asymmetrical GSC division - as they were found in Drosophila - can hardly be translated into the systems where GSC autotomy was reported. It is shown here that the serial autotomy of GSC projections shows remarkable similarities with Wallerian axonal destruction, developmental axon

Stem cell autotomy and niche interaction in different systems

Science.gov (United States)

Dorn, David C; Dorn, August

2015-01-01

The best known cases of cell autotomy are the formation of erythrocytes and thrombocytes (platelets) from progenitor cells that reside in special niches. Recently, autotomy of stem cells and its enigmatic interaction with the niche has been reported from male germline stem cells (GSCs) in several insect species. First described in lepidopterans, the silkmoth, followed by the gipsy moth and consecutively in hemipterans, foremost the milkweed bug. In both, moths and the milkweed bug, GSCs form finger-like projections toward the niche, the apical cells (homologs of the hub cells in Drosophila). Whereas in the milkweed bug the projection terminals remain at the surface of the niche cells, in the gipsy moth they protrude deeply into the singular niche cell. In both cases, the projections undergo serial retrograde fragmentation with progressing signs of autophagy. In the gipsy moth, the autotomized vesicles are phagocytized and digested by the niche cell. In the milkweed bug the autotomized vesicles accumulate at the niche surface and disintegrate. Autotomy and sprouting of new projections appears to occur continuously. The significance of the GSC-niche interactions, however, remains enigmatic. Our concept on the signaling relationship between stem cell-niche in general and GSC and niche (hub cells and cyst stem cells) in particular has been greatly shaped by Drosophila melanogaster. In comparing the interactions of GSCs with their niche in Drosophila with those in species exhibiting GSC autotomy it is obvious that additional or alternative modes of stem cell-niche communication exist. Thus, essential signaling pathways, including niche-stem cell adhesion (E-cadherin) and the direction of asymmetrical GSC division - as they were found in Drosophila - can hardly be translated into the systems where GSC autotomy was reported. It is shown here that the serial autotomy of GSC projections shows remarkable similarities with Wallerian axonal destruction, developmental axon

Propagation of senescent mice using nuclear transfer embryonic stem cell lines.

Science.gov (United States)

Mizutani, Eiji; Ono, Tetsuo; Li, Chong; Maki-Suetsugu, Rinako; Wakayama, Teruhiko

2008-09-01

Senescent mice are often infertile, and the cloning success rate decreases with age, making it almost impossible to produce cloned progeny directly from such animals. In this study, we tried to produce offspring from such "unclonable" senescent mice using nuclear transfer techniques. Donor fibroblasts were obtained from the tail tips of mice aged up to 2 years and 9 months. Although most attempts failed to produce cloned mice by direct somatic cell nuclear transfer, we managed to establish nuclear transfer embryonic stem (ntES) cell lines from all aged mice with an establishment rate of 10-25%, irrespective of sex or strain. Finally, cloned mice were obtained from these ntES cells by a second round of nuclear transfer. In addition, healthy offspring was obtained from all aged donors via germline transmission of ntES cells in chimeric mice. This technique is thus applicable to the propagation of a variety of animals, irrespective of age or fertile potential.

College Students' Conceptions of Stem Cells, Stem Cell Research, and Cloning

Science.gov (United States)

Concannon, James P.; Siegel, Marcelle A.; Halverson, Kristy; Freyermuth, Sharyn

2010-01-01

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…

The Drosophila BCL6 homolog Ken and Barbie promotes somatic stem cell self-renewal in the testis niche.

Science.gov (United States)

Issigonis, Melanie; Matunis, Erika

2012-08-15

Stem cells sustain tissue regeneration by their remarkable ability to replenish the stem cell pool and to generate differentiating progeny. Signals from local microenvironments, or niches, control stem cell behavior. In the Drosophila testis, a group of somatic support cells called the hub creates a stem cell niche by locally activating the Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) pathway in two adjacent types of stem cells: germline stem cells (GSCs) and somatic cyst stem cells (CySCs). Here, we find that ken and barbie (ken) is autonomously required for the self-renewal of CySCs but not GSCs. Furthermore, Ken misexpression in the CySC lineage induces the cell-autonomous self-renewal of somatic cells as well as the nonautonomous self-renewal of germ cells outside the niche. Thus, Ken, like Stat92E and its targets ZFH1 (Leatherman and Dinardo, 2008) and Chinmo (Flaherty et al., 2010), is necessary and sufficient for CySC renewal. However, ken is not a JAK-STAT target in the testis, but instead acts in parallel to Stat92E to ensure CySC self-renewal. Ken represses a subset of Stat92E targets in the embryo (Arbouzova et al., 2006) suggesting that Ken maintains CySCs by repressing differentiation factors. In support of this hypothesis, we find that the global JAK-STAT inhibitor Protein tyrosine phosphatase 61F (Ptp61F) is a JAK-STAT target in the testis that is repressed by Ken. Together, our work demonstrates that Ken has an important role in the inhibition of CySC differentiation. Studies of ken may inform our understanding of its vertebrate orthologue B-Cell Lymphoma 6 (BCL6) and how misregulation of this oncogene leads to human lymphomas. Copyright © 2012 Elsevier Inc. All rights reserved.

Migration and differentiation potential of stem cells in the cnidarian Hydractinia analysed in eGFP-transgenic animals and chimeras.

Science.gov (United States)

Künzel, Timo; Heiermann, Reinhard; Frank, Uri; Müller, Werner; Tilmann, Wido; Bause, Markus; Nonn, Anja; Helling, Matthias; Schwarz, Ryan S; Plickert, Günter

2010-12-01

To analyse cell migration and the differentiation potential of migratory stem cells in Hydractinia, we generated animals with an eGFP reporter gene stably expressed and transmitted via the germline. The transgene was placed under the control of two different actin promoters and the promoter of elongation factor-1α. One actin promoter (Act-II) and the EF-1α promoter enabled expression of the transgene in all cells, the other actin promoter (Act-I) in epithelial and gametogenic cells, but not in the pluripotent migratory stem cells. We produced chimeric animals consisting of histocompatible wild type and transgenic parts. When the transgene was under the control of the epithelial cell specific actin-I promoter, non-fluorescent transgenic stem cells immigrated into wild type tissue, stopped migration and differentiated into epithelial cells which then commenced eGFP-expression. Migratory stem cells are therefore pluripotent and can give rise not only to germ cells, nematocytes and nerve cells, but also to epithelial cells. While in somatic cells expression of the act-I promoter was restricted to epithelial cells it became also active in gametogenesis. The act-I gene is expressed in spermatogonia, oogonia and oocytes. In males the expression pattern showed that migratory stem cells are the precursors of both the spermatogonia and their somatic envelopes. Comparative expression studies using the promoters of the actin-II gene and the elongation factor-1α gene revealed the potential of transgenic techniques to trace the development of the nervous system. Copyright © 2010 Elsevier Inc. All rights reserved.

Plant stem cell niches.

Science.gov (United States)

Stahl, Yvonne; Simon, Rüdiger

2005-01-01

Stem cells are required to support the indeterminate growth style of plants. Meristems are a plants stem cell niches that foster stem cell survival and the production of descendants destined for differentiation. In shoot meristems, stem cell fate is decided at the populational level. The size of the stem cell domain at the meristem tip depends on signals that are exchanged with cells of the organizing centre underneath. In root meristems, individual stem cells are controlled by direct interaction with cells of the quiescent centre that lie in the immediate neighbourhood. Analysis of the interactions and signaling processes in the stem cell niches has delivered some insights into the molecules that are involved and revealed that the two major niches for plant stem cells are more similar than anticipated.

Germline Transgenic Methods for Tracking Cells and Testing Gene Function during Regeneration in the Axolotl

Science.gov (United States)

Khattak, Shahryar; Schuez, Maritta; Richter, Tobias; Knapp, Dunja; Haigo, Saori L.; Sandoval-Guzmán, Tatiana; Hradlikova, Kristyna; Duemmler, Annett; Kerney, Ryan; Tanaka, Elly M.

2013-01-01

The salamander is the only tetrapod that regenerates complex body structures throughout life. Deciphering the underlying molecular processes of regeneration is fundamental for regenerative medicine and developmental biology, but the model organism had limited tools for molecular analysis. We describe a comprehensive set of germline transgenic strains in the laboratory-bred salamander Ambystoma mexicanum (axolotl) that open up the cellular and molecular genetic dissection of regeneration. We demonstrate tissue-dependent control of gene expression in nerve, Schwann cells, oligodendrocytes, muscle, epidermis, and cartilage. Furthermore, we demonstrate the use of tamoxifen-induced Cre/loxP-mediated recombination to indelibly mark different cell types. Finally, we inducibly overexpress the cell-cycle inhibitor p16INK4a, which negatively regulates spinal cord regeneration. These tissue-specific germline axolotl lines and tightly inducible Cre drivers and LoxP reporter lines render this classical regeneration model molecularly accessible. PMID:24052945

What is a stem cell?

Science.gov (United States)

Slack, Jonathan M W

2018-05-15

The historical roots of the stem cell concept are traced with respect to its usage in embryology and in hematology. The modern consensus definition of stem cells, comprising both pluripotent stem cells in culture and tissue-specific stem cells in vivo, is explained and explored. Methods for identifying stem cells are discussed with respect to cell surface markers, telomerase, label retention and transplantability, and properties of the stem cell niche are explored. The CreER method for identifying stem cells in vivo is explained, as is evidence in favor of a stochastic rather than an obligate asymmetric form of cell division. In conclusion, it is found that stem cells do not possess any unique and specific molecular markers; and stem cell behavior depends on the environment of the cell as well as the stem cell's intrinsic qualities. Furthermore, the stochastic mode of division implies that stem cell behavior is a property of a cell population not of an individual cell. In this sense, stem cells do not exist in isolation but only as a part of multicellular system. This article is categorized under: Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches Adult Stem Cells, Tissue Renewal, and Regeneration > Methods and Principles Adult Stem Cells, Tissue Renewal, and Regeneration > Environmental Control of Stem Cells. © 2018 Wiley Periodicals, Inc.

Advancing Stem Cell Biology toward Stem Cell Therapeutics

OpenAIRE

Scadden, David; Srivastava, Alok

2012-01-01

Here, the International Society for Stem Cell Research (ISSCR) Clinical Translation Committee introduces a series of articles outlining the current status, opportunities, and challenges surrounding the clinical translation of stem cell therapeutics for specific medical conditions.

A Rapid Embryonic Stem Cell-Based Mouse Model for B-cell Lymphomas Driven by Epstein-Barr Virus Protein LMP1.

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Ba, Zhaoqing; Meng, Fei-Long; Gostissa, Monica; Huang, Pei-Yi; Ke, Qiang; Wang, Zhe; Dao, Mai N; Fujiwara, Yuko; Rajewsky, Klaus; Zhang, Baochun; Alt, Frederick W

2015-06-01

The Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) contributes to oncogenic human B-cell transformation. Mouse B cells conditionally expressing LMP1 are not predisposed to B-cell malignancies, as LMP1-expressing B cells are eliminated by T cells. However, mice with conditional B-cell LMP1 expression and genetic elimination of α/β and γ/δ T cells ("CLT" mice) die early in association with B-cell lymphoproliferation and lymphomagenesis. Generation of CLT mice involves in-breeding multiple independently segregating alleles. Thus, although introduction of additional activating or knockout mutations into the CLT model is desirable for further B-cell expansion and immunosurveillance studies, doing such experiments by germline breeding is time-consuming, expensive, and sometimes unfeasible. To generate a more tractable model, we generated clonal CLT embryonic stem (ES) cells from CLT embryos and injected them into RAG2-deficient blastocysts to generate chimeric mice, which, like germline CLT mice, harbor splenic CLT B cells and lack T cells. CLT chimeric mice generated by this RAG2-deficient blastocyst complementation ("RDBC") approach die rapidly in association with B-cell lymphoproliferation and lymphoma. Because CLT lymphomas routinely express the activation-induced cytidine deaminase (AID) antibody diversifier, we tested potential AID roles by eliminating the AID gene in CLT ES cells and testing them via RDBC. We found that CLT and AID-deficient CLT ES chimeras had indistinguishable phenotypes, showing that AID is not essential for LMP1-induced lymphomagenesis. Beyond expanding accessibility and utility of CLT mice as a cancer immunotherapy model, our studies provide a new approach for facilitating generation of genetically complex mouse cancer models. ©2015 American Association for Cancer Research.

Formation of germline chimera Gaok chicken used circulation primordial germ cells (circulation PGCs fresh and thawed

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Kostaman T

2014-03-01

Full Text Available Formation of germline chimeras by transfer of chicken primordial germ cells (PGCs is one of the effective techniques for preservation and regeneration of genetic resources in chickens. This study attempted to form germline chimeras of Gaok chicken buy purifying circulated PGCs of donor embryo before it is transferred to the recipient (White Leghorn chickens=WL and studied the ability of recipient embryo on survival in incubators, and hatchability. This study used 200 fertile eggs of Gaok and 90 fertile WL breed all of the eggs was incubated at 380C and 60% humidity in a portable incubator. PGCs-circulation of the blood collected Gaok embryos at stage 14-16 were taken from the dorsal aorta, and then purified by centrifugation method using nycodenz. PGCs-circulation results further purification frozen in liquid nitrogen before being transferred to the recipient embryo. The results showed that for the development of embryos transferred to the fresh circulation of PGCs-circulation as many as 25 cells can survive up to day 14, while one of the transferred of 50 and 100 cells into recipient embryos was hatched (10%. On the contrari recipient embryos that are transferred to the frozen PGCs-circulation the embryos development was shorter, and only survived until day 10th (treatment 25 cells, day 14th (treatment of 50 cells and day 17th (treatment of 100 cells. It is concluded that the amount of PGCs-circulation embryos transferred to the recipient is one factor that influence the success of the development germline chimeras.

Stem cells engineering for cell-based therapy.

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Taupin, Philippe

2007-09-01

Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

Potency of Stem Cells

Indian Academy of Sciences (India)

First page Back Continue Last page Overview Graphics. Potency of Stem Cells. Totipotent Stem Cells (Zygote + first 2 divisions). -Can form placenta, embryo, and any cell of the body. Pluripotent (Embryonic Stem Cells). -Can form any cell of the body but can not form placenta, hence no embryo. Multipotent (Adult stem cells).

Preleukemic and second-hit mutational events in an acute myeloid leukemia patient with a novel germline RUNX1 mutation.

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Ng, Isaac Ks; Lee, Joanne; Ng, Christopher; Kosmo, Bustamin; Chiu, Lily; Seah, Elaine; Mok, Michelle Meng Huang; Tan, Karen; Osato, Motomi; Chng, Wee-Joo; Yan, Benedict; Tan, Lip Kun

2018-01-01

Germline mutations in the RUNX1 transcription factor give rise to a rare autosomal dominant genetic condition classified under the entity: Familial Platelet Disorders with predisposition to Acute Myeloid Leukaemia (FPD/AML). While several studies have identified a myriad of germline RUNX1 mutations implicated in this disorder, second-hit mutational events are necessary for patients with hereditary thrombocytopenia to develop full-blown AML. The molecular picture behind this process remains unclear. We describe a patient of Malay descent with an unreported 7-bp germline RUNX1 frameshift deletion, who developed second-hit mutations that could have brought about the leukaemic transformation from a pre-leukaemic state. These mutations were charted through the course of the treatment and stem cell transplant, showing a clear correlation between her clinical presentation and the mutations present. The patient was a 27-year-old Malay woman who presented with AML on the background of hereditary thrombocytopenia affecting her father and 3 brothers. Initial molecular testing revealed the same novel RUNX1 mutation in all 5 individuals. The patient received standard induction, consolidation chemotherapy, and a haploidentical stem cell transplant from her mother with normal RUNX1 profile. Comprehensive genomic analyses were performed at diagnosis, post-chemotherapy and post-transplant. A total of 8 mutations ( RUNX1 , GATA2 , DNMT3A , BCORL1 , BCOR , 2 PHF6 and CDKN2A ) were identified in the pre-induction sample, of which 5 remained ( RUNX1 , DNMT3A , BCORL1 , BCOR and 1 out of 2 PHF6 ) in the post-treatment sample and none were present post-transplant. In brief, the 3 mutations which were lost along with the leukemic cells at complete morphological remission were most likely acquired leukemic driver mutations that were responsible for the AML transformation from a pre-leukemic germline RUNX1 -mutated state. On the contrary, the 5 mutations that persisted post

Generating chimeric mice from embryonic stem cells via vial coculturing or hypertonic microinjection.

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Lee, Kun-Hsiung

2014-01-01

The generation of a fertile embryonic stem cell (ESC)-derived or F0 (100 % coat color chimerism) mice is the final criterion in proving that the ESC is truly pluripotent. Many methods have been developed to produce chimeric mice. To date, the most popular methods for generating chimeric embryos is well sandwich aggregation between zona pellucida (ZP) removed (denuded) 2.5-day post-coitum (dpc) embryos and ESC clumps, or direct microinjection of ESCs into the cavity (blastocoel) of 3.5-dpc blastocysts. However, due to systemic limitations and the disadvantages of conventional microinjection, aggregation, and coculturing, two novel methods (vial coculturing and hypertonic microinjection) were developed in recent years at my laboratory.Coculturing 2.5-dpc denuded embryos with ESCs in 1.7-mL vials for ~3 h generates chimeras that have significantly high levels of chimerism (including 100 % coat color chimerism) and germline transmission. This method has significantly fewer instrumental and technological limitations than existing methods, and is an efficient, simple, inexpensive, and reproducible method for "mass production" of chimeric embryos. For laboratories without a microinjection system, this is the method of choice for generating chimeric embryos. Microinjecting ESCs into a subzonal space of 2.5-dpc embryos can generate germline-transmitted chimeras including 100 % coat color chimerism. However, this method is adopted rarely due to the very small and tight space between ZP and blastomeres. Using a laser pulse or Piezo-driven instrument/device to help introduce ESCs into the subzonal space of 2.5-dpc embryos demonstrates the superior efficiency in generating ESC-derived (F0) chimeras. Unfortunately, due to the need for an expensive instrument/device and extra fine skill, not many studies have used either method. Recently, ESCs injected into the large subzonal space of 2.5-dpc embryos in an injection medium containing 0.2-0.3 M sucrose very efficiently generated

Retinal stem cells and potential cell transplantation treatments

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Tai-Chi Lin

2014-11-01

Full Text Available The retina, histologically composed of ten delicate layers, is responsible for light perception and relaying electrochemical signals to the secondary neurons and visual cortex. Retinal disease is one of the leading clinical causes of severe vision loss, including age-related macular degeneration, Stargardt's disease, and retinitis pigmentosa. As a result of the discovery of various somatic stem cells, advances in exploring the identities of embryonic stem cells, and the development of induced pluripotent stem cells, cell transplantation treatment for retinal diseases is currently attracting much attention. The sources of stem cells for retinal regeneration include endogenous retinal stem cells (e.g., neuronal stem cells, Müller cells, and retinal stem cells from the ciliary marginal zone and exogenous stem cells (e.g., bone mesenchymal stem cells, adipose-derived stem cells, embryonic stem cells, and induced pluripotent stem cells. The success of cell transplantation treatment depends mainly on the cell source, the timing of cell harvesting, the protocol of cell induction/transplantation, and the microenvironment of the recipient's retina. This review summarizes the different sources of stem cells for regeneration treatment in retinal diseases and surveys the more recent achievements in animal studies and clinical trials. Future directions and challenges in stem cell transplantation are also discussed.

The promises of stem cells: stem cell therapy for movement disorders.

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Mochizuki, Hideki; Choong, Chi-Jing; Yasuda, Toru

2014-01-01

Despite the multitude of intensive research, the exact pathophysiological mechanisms underlying movement disorders including Parkinson's disease, multiple system atrophy and Huntington's disease remain more or less elusive. Treatments to halt these disease progressions are currently unavailable. With the recent induced pluripotent stem cells breakthrough and accomplishment, stem cell research, as the vast majority of scientists agree, holds great promise for relieving and treating debilitating movement disorders. As stem cells are the precursors of all cells in the human body, an understanding of the molecular mechanisms that govern how they develop and work would provide us many fundamental insights into human biology of health and disease. Moreover, stem-cell-derived neurons may be a renewable source of replacement cells for damaged neurons in movement disorders. While stem cells show potential for regenerative medicine, their use as tools for research and drug testing is thought to have more immediate impact. The use of stem-cell-based drug screening technology could be a big boost in drug discovery for these movement disorders. Particular attention should also be given to the involvement of neural stem cells in adult neurogenesis so as to encourage its development as a therapeutic option. Copyright © 2013 Elsevier Ltd. All rights reserved.

Colorectal cancer stem cells.

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Salama, Paul; Platell, Cameron

2009-10-01

Somatic stem cells reside at the base of the crypts throughout the colonic mucosa. These cells are essential for the normal regeneration of the colonic epithelium. The stem cells reside within a special 'niche' comprised of intestinal sub-epithelial myofibroblasts that tightly control their function. It has been postulated that mutations within these adult colonic stem cells may induce neoplastic changes. Such cells can then dissociate from the epithelium and travel into the mesenchyme and thus form invasive cancers. This theory is based on the observation that within a colon cancer, less than 1% of the neoplastic cells have the ability to regenerate the tumour. It is this group of cells that exhibits characteristics of colonic stem cells. Although anti-neoplastic agents can induce remissions by inhibiting cell division, the stem cells appear to be remarkably resistant to both standard chemotherapy and radiotherapy. These stem cells may therefore persist after treatment and form the nucleus for cancer recurrence. Hence, future treatment modalities should focus specifically on controlling the cancer stem cells. In this review, we discuss the biology of normal and malignant colonic stem cells.

Combination cell therapy with mesenchymal stem cells and neural stem cells for brain stroke in rats.

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

2015-05-01

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. 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. 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. 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.

Modeling Human Bone Marrow Failure Syndromes Using Pluripotent Stem Cells and Genome Engineering.

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Jung, Moonjung; Dunbar, Cynthia E; Winkler, Thomas

2015-12-01

The combination of epigenetic reprogramming with advanced genome editing technologies opened a new avenue to study disease mechanisms, particularly of disorders with depleted target tissue. Bone marrow failure syndromes (BMFS) typically present with a marked reduction of peripheral blood cells due to a destroyed or dysfunctional bone marrow compartment. Somatic and germline mutations have been etiologically linked to many cases of BMFS. However, without the ability to study primary patient material, the exact pathogenesis for many entities remained fragmentary. Capturing the pathological genotype in induced pluripotent stem cells (iPSCs) allows studying potential developmental defects leading to a particular phenotype. The lack of hematopoietic stem and progenitor cells in these patients can also be overcome by differentiating patient-derived iPSCs into hematopoietic lineages. With fast growing genome editing techniques, such as CRISPR/Cas9, correction of disease-causing mutations in iPSCs or introduction of mutations in cells from healthy individuals enable comparative studies that may identify other genetic or epigenetic events contributing to a specific disease phenotype. In this review, we present recent progresses in disease modeling of inherited and acquired BMFS using reprogramming and genome editing techniques. We also discuss the challenges and potential shortcomings of iPSC-based models for hematological diseases.

Targeting Homologous Recombination in Notch-Driven C. elegans Stem Cell and Human Tumors.

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Xinzhu Deng

Full Text Available Mammalian NOTCH1-4 receptors are all associated with human malignancy, although exact roles remain enigmatic. Here we employ glp-1(ar202, a temperature-sensitive gain-of-function C. elegans NOTCH mutant, to delineate NOTCH-driven tumor responses to radiotherapy. At ≤20°C, glp-1(ar202 is wild-type, whereas at 25°C it forms a germline stem cell⁄progenitor cell tumor reminiscent of human cancer. We identify a NOTCH tumor phenotype in which all tumor cells traffic rapidly to G2⁄M post-irradiation, attempt to repair DNA strand breaks exclusively via homology-driven repair, and when this fails die by mitotic death. Homology-driven repair inactivation is dramatically radiosensitizing. We show that these concepts translate directly to human cancer models.

Plant stem cell niches.

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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.

Development of hematopoietic stem and progenitor cells from human pluripotent stem cells.

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Chen, Tong; Wang, Fen; Wu, Mengyao; Wang, Zack Z

2015-07-01

Human pluripotent stem cells (hPSCs), including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), provide a new cell source for regenerative medicine, disease modeling, drug discovery, and preclinical toxicity screening. Understanding of the onset and the sequential process of hematopoietic cells from differentiated hPSCs will enable the achievement of personalized medicine and provide an in vitro platform for studying of human hematopoietic development and disease. During embryogenesis, hemogenic endothelial cells, a specified subset of endothelial cells in embryonic endothelium, are the primary source of multipotent hematopoietic stem cells. In this review, we discuss current status in the generation of multipotent hematopoietic stem and progenitor cells from hPSCs via hemogenic endothelial cells. We also review the achievements in direct reprogramming from non-hematopoietic cells to hematopoietic stem and progenitor cells. Further characterization of hematopoietic differentiation in hPSCs will improve our understanding of blood development and expedite the development of hPSC-derived blood products for therapeutic purpose. © 2015 Wiley Periodicals, Inc.

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

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Samantha Hughes

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

Single-cell sequencing in stem cell biology.

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Wen, Lu; Tang, Fuchou

2016-04-15

Cell-to-cell variation and heterogeneity are fundamental and intrinsic characteristics of stem cell populations, but these differences are masked when bulk cells are used for omic analysis. Single-cell sequencing technologies serve as powerful tools to dissect cellular heterogeneity comprehensively and to identify distinct phenotypic cell types, even within a 'homogeneous' stem cell population. These technologies, including single-cell genome, epigenome, and transcriptome sequencing technologies, have been developing rapidly in recent years. The application of these methods to different types of stem cells, including pluripotent stem cells and tissue-specific stem cells, has led to exciting new findings in the stem cell field. In this review, we discuss the recent progress as well as future perspectives in the methodologies and applications of single-cell omic sequencing technologies.

Pluripotent stem cell-derived neural stem cells: From basic research to applications

OpenAIRE

Otsu, Masahiro; Nakayama, Takashi; Inoue, Nobuo

2014-01-01

Basic research on pluripotent stem cells is designed to enhance understanding of embryogenesis, whereas applied research is designed to develop novel therapies and prevent diseases. Attainment of these goals has been enhanced by the establishment of embryonic stem cell lines, the technological development of genomic reprogramming to generate induced-pluripotent stem cells, and improvements in vitro techniques to manipulate stem cells. This review summarizes the techniques required to generate...

Stem cell therapy for diabetes

Directory of Open Access Journals (Sweden)

K O Lee

2012-01-01

Full Text Available Stem cell therapy holds immense promise for the treatment of patients with diabetes mellitus. Research on the ability of human embryonic stem cells to differentiate into islet cells has defined the developmental stages and transcription factors involved in this process. However, the clinical applications of human embryonic stem cells are limited by ethical concerns, as well as the potential for teratoma formation. As a consequence, alternative forms of stem cell therapies, such as induced pluripotent stem cells, umbilical cord stem cells and bone marrow-derived mesenchymal stem cells, have become an area of intense study. Recent advances in stem cell therapy may turn this into a realistic treatment for diabetes in the near future.

Induced pluripotent stem (iPS) cells from human fetal stem cells.

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Guillot, Pascale V

2016-02-01

Pluripotency defines the ability of stem cells to differentiate into all the lineages of the three germ layers and self-renew indefinitely. Somatic cells can regain the developmental potential of embryonic stem cells following ectopic expression of a set of transcription factors or, in certain circumstances, via modulation of culture conditions and supplementation with small molecule, that is, induced pluripotent stem (iPS) cells. Here, we discuss the use of fetal tissues for reprogramming, focusing in particular on stem cells derived from human amniotic fluid, and the development of chemical reprogramming. We next address the advantages and disadvantages of deriving pluripotent cells from fetal tissues and the potential clinical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Stem cell clinics online: the direct-to-consumer portrayal of stem cell medicine.

Science.gov (United States)

Lau, Darren; Ogbogu, Ubaka; Taylor, Benjamin; Stafinski, Tania; Menon, Devidas; Caulfield, Timothy

2008-12-04

Despite the immature state of stem cell medicine, patients are seeking and accessing putative stem cell therapies in an "early market" in which direct-to-consumer advertising via the internet likely plays an important role. We analyzed stem cell clinic websites and appraised the relevant published clinical evidence of stem cell therapies to address three questions about the direct-to-consumer portrayal of stem cell medicine in this early market: What sorts of therapies are being offered? How are they portrayed? Is there clinical evidence to support the use of these therapies? We found that the portrayal of stem cell medicine on provider websites is optimistic and unsubstantiated by peer-reviewed literature.

[Progress in epidermal stem cells].

Science.gov (United States)

Wang, Li-Juan; Wang, You-Liang; Yang, Xiao

2010-03-01

Mammalian skin epidermis contains different epidermal stem cell pools which contribute to the homeostasis and repair of skin epithelium. Epidermal stem cells possess two essential features common to all stem cells: self-renewal and differentiation. Disturbing the balance between self-renewal and differentiation of epidermal stem cell often causes tumors or other skin diseases. Epidermal stem cell niches provide a special microenvironment that maintains a balance of stem cell quiescence and activity. This review primarily concentrates on the following points of the epidermal stem cells: the existing evidences, the self-renewal and differentiation, the division pattern, the signal pathways regulating self-renewal and differentiation, and the microenvironment (niche) and macroenvironment maintaining the homeostasis of stem cells.

Dental Stem Cell in Tooth Development and Advances of Adult Dental Stem Cell in Regenerative Therapies.

Science.gov (United States)

Tan, Jiali; Xu, Xin; Lin, Jiong; Fan, Li; Zheng, Yuting; Kuang, Wei

2015-01-01

Stem cell-based therapies are considered as a promising treatment for many clinical usage such as tooth regeneration, bone repairation, spinal cord injury, and so on. However, the ideal stem cell for stem cell-based therapy still remains to be elucidated. In the past decades, several types of stem cells have been isolated from teeth, including dental pulp stem cells (DPSCs), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), dental follicle progenitor stem cells (DFPCs) and stem cells from apical papilla (SCAP), which may be a good source for stem cell-based therapy in certain disease, especially when they origin from neural crest is considered. In this review, the specific characteristics and advantages of the adult dental stem cell population will be summarized and the molecular mechanisms of the differentiation of dental stem cell during tooth development will be also discussed.

Engineering stem cell niches in bioreactors

OpenAIRE

Liu, Meimei; Liu, Ning; Zang, Ru; Li, Yan; Yang, Shang-Tian

2013-01-01

Stem cells, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells and amniotic fluid stem cells have the potential to be expanded and differentiated into various cell types in the body. Efficient differentiation of stem cells with the desired tissue-specific function is critical for stem cell-based cell therapy, tissue engineering, drug discovery and disease modeling. Bioreactors provide a great platform to regulate the stem cell microenvironment, known as “ni...

Induced pluripotent stem (iPS) cells from human fetal stem cells

OpenAIRE

Guillot, P. V.

2016-01-01

Pluripotency defines the ability of stem cells to differentiate into all the lineages of the three germ layers and self-renew indefinitely. Somatic cells can regain the developmental potential of embryonic stem cells following ectopic expression of a set of transcription factors or, in certain circumstances, via modulation of culture conditions and supplementation with small molecule, that is, induced pluripotent stem (iPS) cells. Here, we discuss the use of fetal tissues for reprogramming, f...

Brain mesenchymal stem cells: The other stem cells of the brain?

Science.gov (United States)

Appaix, Florence; Nissou, Marie-France; van der Sanden, Boudewijn; Dreyfus, Matthieu; Berger, François; Issartel, Jean-Paul; Wion, Didier

2014-04-26

Multipotent mesenchymal stromal cells (MSC), have the potential to differentiate into cells of the mesenchymal lineage and have non-progenitor functions including immunomodulation. The demonstration that MSCs are perivascular cells found in almost all adult tissues raises fascinating perspectives on their role in tissue maintenance and repair. However, some controversies about the physiological role of the perivascular MSCs residing outside the bone marrow and on their therapeutic potential in regenerative medicine exist. In brain, perivascular MSCs like pericytes and adventitial cells, could constitute another stem cell population distinct to the neural stem cell pool. The demonstration of the neuronal potential of MSCs requires stringent criteria including morphological changes, the demonstration of neural biomarkers expression, electrophysiological recordings, and the absence of cell fusion. The recent finding that brain cancer stem cells can transdifferentiate into pericytes is another facet of the plasticity of these cells. It suggests that the perversion of the stem cell potential of pericytes might play an even unsuspected role in cancer formation and tumor progression.

Stem cell migration after irradiation

International Nuclear Information System (INIS)

Nothdurft, W.; Fliedner, T.M.

1979-01-01

The survival rate of irradiated rodents could be significantly improved by shielding only the small parts of hemopoietic tissues during the course of irradiation. The populations of circulating stem cells in adult organisms are considered to be of some importance for the homeostasis between the many sites of blood cell formation and for the necessary flexibility of hemopoietic response in the face of fluctuating demands. Pluripotent stem cells are migrating through peripheral blood as has been shown for several mammalian species. Under steady state conditions, the exchange of stem cells between the different sites of blood cell formation appears to be restricted. Their presence in blood and the fact that they are in balance with the extravascular stem cell pool may well be of significance for the surveilance of the integrity of local stem cell populations. Any decrease of stem cell population in blood below a critical size results in the rapid immigration of circulating stem cells in order to restore local stem cell pool size. Blood stem cells are involved in the regeneration after whole-body irradiation if the stem cell population in bone marrows is reduced to less than 10% of the normal state. In the animals subjected to partial-body irradiation, the circulating stem cells appear to be the only source for the repopulation of the heavily irradiated, aplastic sites of hemopoietic organs. (Yamashita, S.)

Biochemistry of epidermal stem cells.

Science.gov (United States)

Eckert, Richard L; Adhikary, Gautam; Balasubramanian, Sivaprakasam; Rorke, Ellen A; Vemuri, Mohan C; Boucher, Shayne E; Bickenbach, Jackie R; Kerr, Candace

2013-02-01

The epidermis is an important protective barrier that is essential for maintenance of life. Maintaining this barrier requires continuous cell proliferation and differentiation. Moreover, these processes must be balanced to produce a normal epidermis. The stem cells of the epidermis reside in specific locations in the basal epidermis, hair follicle and sebaceous glands and these cells are responsible for replenishment of this tissue. A great deal of effort has gone into identifying protein epitopes that mark stem cells, in identifying stem cell niche locations, and in understanding how stem cell populations are related. We discuss these studies as they apply to understanding normal epidermal homeostasis and skin cancer. An assortment of stem cell markers have been identified that permit assignment of stem cells to specific regions of the epidermis, and progress has been made in understanding the role of these cells in normal epidermal homeostasis and in conditions of tissue stress. A key finding is the multiple stem cell populations exist in epidermis that give rise to different structures, and that multiple stem cell types may contribute to repair in damaged epidermis. Understanding epidermal stem cell biology is likely to lead to important therapies for treating skin diseases and cancer, and will also contribute to our understanding of stem cells in other systems. This article is part of a Special Issue entitled Biochemistry of Stem Cells. Copyright © 2012 Elsevier B.V. All rights reserved.

Genome editing in pluripotent stem cells: research and therapeutic applications

Energy Technology Data Exchange (ETDEWEB)

Deleidi, Michela, E-mail: michela.deleidi@dzne.de [German Center for Neurodegenerative Diseases (DZNE) Tübingen within the Helmholtz Association, Tübingen (Germany); Hertie Institute for Clinical Brain Research, University of Tübingen (Germany); Yu, Cong [Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo, New York (United States)

2016-05-06

Recent progress in human pluripotent stem cell (hPSC) and genome editing technologies has opened up new avenues for the investigation of human biology in health and disease as well as the development of therapeutic applications. Gene editing approaches with programmable nucleases have been successfully established in hPSCs and applied to study gene function, develop novel animal models and perform genetic and chemical screens. Several studies now show the successful editing of disease-linked alleles in somatic and patient-derived induced pluripotent stem cells (iPSCs) as well as in animal models. Importantly, initial clinical trials have shown the safety of programmable nucleases for ex vivo somatic gene therapy. In this context, the unlimited proliferation potential and the pluripotent properties of iPSCs may offer advantages for gene targeting approaches. However, many technical and safety issues still need to be addressed before genome-edited iPSCs are translated into the clinical setting. Here, we provide an overview of the available genome editing systems and discuss opportunities and perspectives for their application in basic research and clinical practice, with a particular focus on hPSC based research and gene therapy approaches. Finally, we discuss recent research on human germline genome editing and its social and ethical implications. - Highlights: • Programmable nucleases have proven efficient and specific for genome editing in human pluripotent stem cells (hPSCs). • Genome edited hPSCs can be employed to study gene function in health and disease as well as drug and chemical screens. • Genome edited hPSCs hold great promise for ex vivo gene therapy approaches. • Technical and safety issues should be first addressed to advance the clinical use of gene-edited hPSCs.

Genome editing in pluripotent stem cells: research and therapeutic applications

International Nuclear Information System (INIS)

Deleidi, Michela; Yu, Cong

2016-01-01

Recent progress in human pluripotent stem cell (hPSC) and genome editing technologies has opened up new avenues for the investigation of human biology in health and disease as well as the development of therapeutic applications. Gene editing approaches with programmable nucleases have been successfully established in hPSCs and applied to study gene function, develop novel animal models and perform genetic and chemical screens. Several studies now show the successful editing of disease-linked alleles in somatic and patient-derived induced pluripotent stem cells (iPSCs) as well as in animal models. Importantly, initial clinical trials have shown the safety of programmable nucleases for ex vivo somatic gene therapy. In this context, the unlimited proliferation potential and the pluripotent properties of iPSCs may offer advantages for gene targeting approaches. However, many technical and safety issues still need to be addressed before genome-edited iPSCs are translated into the clinical setting. Here, we provide an overview of the available genome editing systems and discuss opportunities and perspectives for their application in basic research and clinical practice, with a particular focus on hPSC based research and gene therapy approaches. Finally, we discuss recent research on human germline genome editing and its social and ethical implications. - Highlights: • Programmable nucleases have proven efficient and specific for genome editing in human pluripotent stem cells (hPSCs). • Genome edited hPSCs can be employed to study gene function in health and disease as well as drug and chemical screens. • Genome edited hPSCs hold great promise for ex vivo gene therapy approaches. • Technical and safety issues should be first addressed to advance the clinical use of gene-edited hPSCs.

Strategies to improve homing of mesenchymal stem cells for greater efficacy in stem cell therapy.

Science.gov (United States)

Naderi-Meshkin, Hojjat; Bahrami, Ahmad Reza; Bidkhori, Hamid Reza; Mirahmadi, Mahdi; Ahmadiankia, Naghmeh

2015-01-01

Stem/progenitor cell-based therapeutic approach in clinical practice has been an elusive dream in medical sciences, and improvement of stem cell homing is one of major challenges in cell therapy programs. Stem/progenitor cells have a homing response to injured tissues/organs, mediated by interactions of chemokine receptors expressed on the cells and chemokines secreted by the injured tissue. For improvement of directed homing of the cells, many techniques have been developed either to engineer stem/progenitor cells with higher amount of chemokine receptors (stem cell-based strategies) or to modulate the target tissues to release higher level of the corresponding chemokines (target tissue-based strategies). This review discusses both of these strategies involved in the improvement of stem cell homing focusing on mesenchymal stem cells as most frequent studied model in cellular therapies. © 2014 International Federation for Cell Biology.

A recurrent germline PAX5 mutation confers susceptibility to pre-B cell acute lymphoblastic leukemia

NARCIS (Netherlands)

Shah, S.; Schrader, K.A.; Waanders, E.; Timms, A.E.; Vijai, J.; Miething, C.; Wechsler, J.; Yang, J.; Hayes, J.; Klein, R.J.; Zhang, J.; Wei, L.; Wu, G.; Rusch, M.; Nagahawatte, P.; Ma, J; Chen, S.C.; Song, G.; Cheng, J.; Meyers, P.; Bhojwani, D.; Jhanwar, S.; Maslak, P.; Fleisher, M.; Littman, J.; Offit, L.; Rau-Murthy, R.; Fleischut, M.H.; Corines, M.; Murali, R.; Gao, X.; Manschreck, C.; Kitzing, T.; Murty, V.V.; Raimondi, S.C.; Kuiper, R.P.; Simons, A.; Schiffman, J.D.; Onel, K.; Plon, S.E.; Wheeler, D.A.; Ritter, D.; Ziegler, D.S.; Tucker, K.; Sutton, R.; Chenevix-Trench, G.; Li, J.; Huntsman, D.G.; Hansford, S.; Senz, J.; Walsh, T.; Lee (Helen Dowling Instituut), M. van der; Hahn, C.N.; Roberts, K.G.; King, M.C.; Lo, S.M.; Levine, R.L.; Viale, A.; Socci, N.D.; Nathanson, K.L.; Scott, H.S.; Daly, M.; Lipkin, S.M.; Lowe, S.W.; Downing, J.R.; Altshuler, D.; Sandlund, J.T.; Horwitz, M.S.; Mullighan, C.G.; Offit, K.

2013-01-01

Somatic alterations of the lymphoid transcription factor gene PAX5 (also known as BSAP) are a hallmark of B cell precursor acute lymphoblastic leukemia (B-ALL), but inherited mutations of PAX5 have not previously been described. Here we report a new heterozygous germline variant, c.547G>A

Mammary Stem Cells and Breast Cancer Stem Cells: Molecular Connections and Clinical Implications.

Science.gov (United States)

Celià-Terrassa, Toni

2018-05-04

Cancer arises from subpopulations of transformed cells with high tumor initiation and repopulation ability, known as cancer stem cells (CSCs), which share many similarities with their normal counterparts. In the mammary gland, several studies have shown common molecular regulators between adult mammary stem cells (MaSCs) and breast cancer stem cells (bCSCs). Cell plasticity and self-renewal are essential abilities for MaSCs to maintain tissue homeostasis and regenerate the gland after pregnancy. Intriguingly, these properties are similarly executed in breast cancer stem cells to drive tumor initiation, tumor heterogeneity and recurrence after chemotherapy. In addition, both stem cell phenotypes are strongly influenced by external signals from the microenvironment, immune cells and supportive specific niches. This review focuses on the intrinsic and extrinsic connections of MaSC and bCSCs with clinical implications for breast cancer progression and their possible therapeutic applications.

Stem cells in dentistry: A study regarding awareness of stem cells among dental professionals

OpenAIRE

Parita K Chitroda; Girish Katti; Nikhat M Attar; Syed Shahbaz; G Sreenivasarao; Ambika Patil

2017-01-01

Background: Dental stem cell, a type of adult stem cell, exhibits multipotent differentiation capacity and is drawing worldwide attention because of its numerous applications. The advances in applications of dental stem cells seem to be unsurpassed in the near future, for which specialized skills and knowledge in this arena are of prime significance. Hence, there is a need to acquire more knowledge about dental stem cells to obtain maximum benefits from it in the coming years. Dental stem cel...

The neural stem cell fate determinant TLX promotes tumorigenesis and genesis of cells resembling glioma stem cells.

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Park, Hyo-Jung; Kim, Jun-Kyum; Jeon, Hye-Min; Oh, Se-Yeong; Kim, Sung-Hak; Nam, Do-Hyun; Kim, Hyunggee

2010-11-01

A growing body of evidence indicates that deregulation of stem cell fate determinants is a hallmark of many types of malignancies. The neural stem cell fate determinant TLX plays a pivotal role in neurogenesis in the adult brain by maintaining neural stem cells. Here, we report a tumorigenic role of TLX in brain tumor initiation and progression. Increased TLX expression was observed in a number of glioma cells and glioma stem cells, and correlated with poor survival of patients with gliomas. Ectopic expression of TLX in the U87MG glioma cell line and Ink4a/Arf-deficient mouse astrocytes (Ink4a/Arf(-/-) astrocytes) induced cell proliferation with a concomitant increase in cyclin D expression, and accelerated foci formation in soft agar and tumor formation in in vivo transplantation assays. Furthermore, overexpression of TLX in Ink4a/Arf(-/-) astrocytes inhibited cell migration and invasion and promoted neurosphere formation and Nestin expression, which are hallmark characteristics of glioma stem cells, under stem cell culture conditions. Our results indicate that TLX is involved in glioma stem cell genesis and represents a potential therapeutic target for this type of malignancy.

The cancer-germline antigen SSX2 causes cell cycle arrest and DNA damage in cancer cells

DEFF Research Database (Denmark)

Greve, Katrine Buch Vidén; Lindgreen, Jonas; Terp, Mikkel Green

2011-01-01

The SSX family of cancer and germline antigens is mainly expressed in the germ cells of healthy individuals as well as wide range of cancers and is therefore potential targets for immunotherapy. However, little is known about the role of SSX proteins in tumorigenesis and normal cell function. Here......, we show that SSX2 is involved in regulation of cancer cell growth. We found that ectopic expression of SSX2 in melanoma and colon cancer cells strongly reduced cell growth and induced apoptosis in vitro. Importantly, in a xenograft mouse model, the growth of tumors derived from SSX2 overexpressing...... melanoma cells was severely reduced compared to those derived from the isogenic parental cell line. Cell cycle analysis showed that SSX2 caused an accumulation of cells arrested in G1. Consistent with this, we observed a marked decrease in cells expressing the proliferation marker Ki67 and concomitantly...

The Androgen Receptor Bridges Stem Cell-Associated Signaling Nodes in Prostate Stem Cells

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Alastair H. Davies

2016-01-01

Full Text Available The therapeutic potential of stem cells relies on dissecting the complex signaling networks that are thought to regulate their pluripotency and self-renewal. Until recently, attention has focused almost exclusively on a small set of “core” transcription factors for maintaining the stem cell state. It is now clear that stem cell regulatory networks are far more complex. In this review, we examine the role of the androgen receptor (AR in coordinating interactions between signaling nodes that govern the balance of cell fate decisions in prostate stem cells.

Cancer stem cells and differentiation therapy.

Science.gov (United States)

Jin, Xiong; Jin, Xun; Kim, Hyunggee

2017-10-01

Cancer stem cells can generate tumors from only a small number of cells, whereas differentiated cancer cells cannot. The prominent feature of cancer stem cells is its ability to self-renew and differentiate into multiple types of cancer cells. Cancer stem cells have several distinct tumorigenic abilities, including stem cell signal transduction, tumorigenicity, metastasis, and resistance to anticancer drugs, which are regulated by genetic or epigenetic changes. Like normal adult stem cells involved in various developmental processes and tissue homeostasis, cancer stem cells maintain their self-renewal capacity by activating multiple stem cell signaling pathways and inhibiting differentiation signaling pathways during cancer initiation and progression. Recently, many studies have focused on targeting cancer stem cells to eradicate malignancies by regulating stem cell signaling pathways, and products of some of these strategies are in preclinical and clinical trials. In this review, we describe the crucial features of cancer stem cells related to tumor relapse and drug resistance, as well as the new therapeutic strategy to target cancer stem cells named "differentiation therapy."

[Perinatal sources of stem cells].

Science.gov (United States)

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.

Transfer of stem cells carrying engineered chromosomes with XY clone laser system.

Science.gov (United States)

Sinko, Ildiko; Katona, Robert L

2011-01-01

Current transgenic technologies for gene transfer into the germline of mammals cause a random integration of exogenous naked DNA into the host genome that can generate undesirable position effects as well as insertional mutations. The vectors used to generate transgenic animals are limited by the amount of foreign DNA they can carry. Mammalian artificial chromosomes have large DNA-carrying capacity and ability to replicate in parallel with, but without integration into, the host genome. Hence they are attractive vectors for transgenesis, cellular protein production, and gene therapy applications as well. ES cells mediated chromosome transfer by conventional blastocyst injection has a limitation in unpredictable germline transmission. The demonstrated protocol of laser-assisted microinjection of artificial chromosome containing ES cells into eight-cell mouse embryos protocol described here can solve the problem for faster production of germline transchromosomic mice.

Materials as stem cell regulators

Science.gov (United States)

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

Dental pulp stem cells

DEFF Research Database (Denmark)

Ashri, N. Y.; Ajlan, S. A.; Aldahmash, Abdullah M.

2015-01-01

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...... an updated review on dental pulp stem cells and their applications in periodontal regeneration, in combination with different scaffolds and growth factors....

Stem Cell Therapy for Erectile Dysfunction.

Science.gov (United States)

Matz, Ethan L; Terlecki, Ryan; Zhang, Yuanyuan; Jackson, John; Atala, Anthony

2018-04-06

The prevalence of erectile dysfunction (ED) is substantial and continues to rise. Current therapeutics for ED consist of oral medications, intracavernosal injections, vacuum erection devices, and penile implants. While such options may manage the disease state, none of these modalities, however, restore function. Stem cell therapy has been evaluated for erectile restoration in animal models. These cells have been derived from multiple tissues, have varied potential, and may function via local engraftment or paracrine signaling. Bone marrow-derived stem cells (BMSC) and adipose-derived stem cells (ASC) have both been used in these models with noteworthy effects. Herein, we will review the pathophysiology of ED, animal models, current and novel stem-cell based therapeutics, clinical trials and areas for future research. The relevant literature and contemporary data using keywords, "stem cells and erectile dysfunction" was reviewed. Examination of evidence supporting the association between erectile dysfunction and adipose derived stem cells, bone marrow derived stem cells, placental stem cells, urine stem cells and stem cell therapy respectively. Placental-derived stem cells and urine-derived stem cells possess many similar properties as BMSC and ASC, but the methods of acquisition are favorable. Human clinical trials have already demonstrated successful use of stem cells for improvement of erectile function. The future of stem cell research is constantly being evaluated, although, the evidence suggests a place for stem cells in erectile dysfunction therapeutics. Matz EL, Terlecki R, Zhang Y, et al. Stem Cell Therapy for Erectile Dysfunction. Sex Med Rev 2018;XX:XXX-XXX. Copyright © 2018 International Society for Sexual Medicine. Published by Elsevier Inc. All rights reserved.

Biomaterial-stem cell interactions and their impact on stem cell response

NARCIS (Netherlands)

Oziemlak-Schaap, Aneta M.; Kuhn, Philipp T.; van Kooten, Theo G.; van Rijn, Patrick

2014-01-01

In this review, current research in the field of biomaterial properties for directing stem cells are discussed and placed in a critical perspective. Regenerative medicine, in which stem cells play a crucial role, has become an interdisciplinary field between cell biology and materials science. New

Repression of germline RNAi pathways in somatic cells by retinoblastoma pathway chromatin complexes.

Directory of Open Access Journals (Sweden)

Xiaoyun Wu

Full Text Available The retinoblastoma (Rb tumor suppressor acts with a number of chromatin cofactors in a wide range of species to suppress cell proliferation. The Caenorhabditis elegans retinoblastoma gene and many of these cofactors, called synMuv B genes, were identified in genetic screens for cell lineage defects caused by growth factor misexpression. Mutations in many synMuv B genes, including lin-35/Rb, also cause somatic misexpression of the germline RNA processing P granules and enhanced RNAi. We show here that multiple small RNA components, including a set of germline-specific Argonaute genes, are misexpressed in the soma of many synMuv B mutant animals, revealing one node for enhanced RNAi. Distinct classes of synMuv B mutants differ in the subcellular architecture of their misexpressed P granules, their profile of misexpressed small RNA and P granule genes, as well as their enhancement of RNAi and the related silencing of transgenes. These differences define three classes of synMuv B genes, representing three chromatin complexes: a LIN-35/Rb-containing DRM core complex, a SUMO-recruited Mec complex, and a synMuv B heterochromatin complex, suggesting that intersecting chromatin pathways regulate the repression of small RNA and P granule genes in the soma and the potency of RNAi. Consistent with this, the DRM complex and the synMuv B heterochromatin complex were genetically additive and displayed distinct antagonistic interactions with the MES-4 histone methyltransferase and the MRG-1 chromodomain protein, two germline chromatin regulators required for the synMuv phenotype and the somatic misexpression of P granule components. Thus intersecting synMuv B chromatin pathways conspire with synMuv B suppressor chromatin factors to regulate the expression of small RNA pathway genes, which enables heightened RNAi response. Regulation of small RNA pathway genes by human retinoblastoma may also underlie its role as a tumor suppressor gene.

Embryonic stem cells require Wnt proteins to prevent differentiation to epiblast stem cells

NARCIS (Netherlands)

D. ten Berge (Derk); D. Kurek (Dorota); T. Blauwkamp (Tim); W. Koole (Wouter); A. Maas (Alex); E. Eroglu (Elif); R.K. Siu (Ronald); R. Nusse (Roel)

2011-01-01

textabstractPluripotent stem cells exist in naive and primed states, epitomized by mouse embryonic stem cells (ESCs) and the developmentally more advanced epiblast stem cells (EpiSCs; ref.). In the naive state of ESCs, the genome has an unusual open conformation and possesses a minimum of repressive

Perinatal sources of stem cells

Directory of Open Access Journals (Sweden)

Magdalena Maria Piskorska-Jasiulewicz

2015-03-01

Full Text Available 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.

TOPICAL REVIEW: Stem cells engineering for cell-based therapy

Science.gov (United States)

Taupin, Philippe

2007-09-01

Stem cells carry the promise to cure a broad range of diseases and injuries, from diabetes, heart and muscular diseases, to neurological diseases, disorders and injuries. Significant progresses have been made in stem cell research over the past decade; the derivation of embryonic stem cells (ESCs) from human tissues, the development of cloning technology by somatic cell nuclear transfer (SCNT) and the confirmation that neurogenesis occurs in the adult mammalian brain and that neural stem cells (NSCs) reside in the adult central nervous system (CNS), including that of humans. Despite these advances, there may be decades before stem cell research will translate into therapy. Stem cell research is also subject to ethical and political debates, controversies and legislation, which slow its progress. Cell engineering has proven successful in bringing genetic research to therapy. In this review, I will review, in two examples, how investigators are applying cell engineering to stem cell biology to circumvent stem cells' ethical and political constraints and bolster stem cell research and therapy.

Road for understanding cancer stem cells

DEFF Research Database (Denmark)

Serakinci, Nedime; Erzik, Can

2007-01-01

There is increasing evidence suggesting that stem cells are susceptive to carcinogenesis and, consequently, can be the origin of many cancers. Recently, the neoplastic potential of stem cells has been supported by many groups showing the existence of subpopulations with stem cell characteristics...... in tumor biopsies such as brain and breast. Evidence supporting the cancer stem cell hypothesis has gained impact due to progress in stem cell biology and development of new models to validate the self-renewal potential of stem cells. Recent evidence on the possible identification of cancer stem cells may...... offer an opportunity to use these cells as future therapeutic targets. Therefore, model systems in this field have become very important and useful. This review will focus on the state of knowledge on cancer stem cell research, including cell line models for cancer stem cells. The latter will, as models...

Hidden in the crowd: primordial germ cells and somatic stem cells in the mesodermal posterior growth zone of the polychaete Platynereis dumerillii are two distinct cell populations

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Rebscher Nicole

2012-04-01

Full Text Available Abstract Background In the polychaete Platynereis, the primordial germ cells (PGCs emerge from the vasa, piwi, and PL10 expressing mesodermal posterior growth zone (MPGZ at the end of larval development, suggesting a post-embryonic formation from stem cells. Methods In order to verify this hypothesis, embryos and larvae were pulse labeled with the proliferation marker 5-ethynyl-2'-deoxyuridine (EdU at different stages of development. Subsequently, the PGCs were visualized in 7-day-old young worms using antibodies against the Vasa protein. Results Surprisingly, the primordial germ cells of Platynereis incorporate EdU only shortly before gastrulation (6-8 hours post fertilization (hpf, which coincides with the emergence of four small blastomeres from the mesoblast lineage. We conclude that these so-called 'secondary mesoblast cells' constitute the definitive PGCs in Platynereis. In contrast, the cells of the MPGZ incorporate EdU only from the pre-trochophore stage onward (14 hpf. Conclusion While PGCs and the cells of the MPGZ in Platynereis are indistinguishable in morphology and both express the germline markers vasa, nanos, and piwi, a distinct cluster of PGCs is detectable anterior of the MPGZ following EdU pulse-labeling. Indeed the PGCs form independently from the stem cells of the MPGZ prior to gastrulation. Our data suggest an early PGC formation in the polychaete by preformation rather than by epigenesis.

Myeloproliferative neoplasm stem cells.

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Mead, Adam J; Mullally, Ann

2017-03-23

Myeloproliferative neoplasms (MPNs) arise in the hematopoietic stem cell (HSC) compartment as a result of the acquisition of somatic mutations in a single HSC that provides a selective advantage to mutant HSC over normal HSC and promotes myeloid differentiation to engender a myeloproliferative phenotype. This population of somatically mutated HSC, which initiates and sustains MPNs, is termed MPN stem cells. In >95% of cases, mutations that drive the development of an MPN phenotype occur in a mutually exclusive manner in 1 of 3 genes: JAK2 , CALR , or MPL The thrombopoietin receptor, MPL, is the key cytokine receptor in MPN development, and these mutations all activate MPL-JAK-STAT signaling in MPN stem cells. Despite common biological features, MPNs display diverse disease phenotypes as a result of both constitutional and acquired factors that influence MPN stem cells, and likely also as a result of heterogeneity in the HSC in which MPN-initiating mutations arise. As the MPN clone expands, it exerts cell-extrinsic effects on components of the bone marrow niche that can favor the survival and expansion of MPN stem cells over normal HSC, further sustaining and driving malignant hematopoiesis. Although developed as targeted therapies for MPNs, current JAK2 inhibitors do not preferentially target MPN stem cells, and as a result, rarely induce molecular remissions in MPN patients. As the understanding of the molecular mechanisms underlying the clonal dominance of MPN stem cells advances, this will help facilitate the development of therapies that preferentially target MPN stem cells over normal HSC. © 2017 by The American Society of Hematology.

Stem Cell Transplant

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... Graft-versus-host disease: A potential risk when stem cells come from donors If you receive a transplant ... medications and blood products into your body. Collecting stem cells for transplant If a transplant using your own ...

Skin Stem Cells in Skin Cell Therapy

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Mollapour Sisakht

2015-12-01

Full Text Available Context Preclinical and clinical research has shown that stem cell therapy is a promising therapeutic option for many diseases. This article describes skin stem cells sources and their therapeutic applications. Evidence Acquisition Compared with conventional methods, cell therapy reduces the surgical burden for patients because it is simple and less time-consuming. Skin cell therapy has been developed for variety of diseases. By isolation of the skin stem cell from the niche, in vitro expansion and transplantation of cells offers a surprising healing capacity profile. Results Stem cells located in skin cells have shown interesting properties such as plasticity, transdifferentiation, and specificity. Mesenchymal cells of the dermis, hypodermis, and other sources are currently being investigated to promote regeneration. Conclusions Because skin stem cells are highly accessible from autologous sources and their immunological profile is unique, they are ideal for therapeutic approaches. Optimization of administrative routes requires more investigation own to the lack of a standard protocol.

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

International Nuclear Information System (INIS)

Varga, Nóra; Veréb, Zoltán; Rajnavölgyi, Éva; Német, Katalin; Uher, Ferenc; Sarkadi, Balázs; Apáti, Ágota

2011-01-01

Highlights: ► MSC like cells were derived from hESC by a simple and reproducible method. ► Differentiation and immunosuppressive features of MSCl cells were similar to bmMSC. ► 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.

Stem Cells and Aging.

Science.gov (United States)

Koliakos, George

2017-02-01

The article is a presentation at the 4th Conference of ESAAM, which took place on October 30-31, 2015, in Athens, Greece. Its purpose was not to cover all aspects of cellular aging but to share with the audience of the Conference, in a 15-minute presentation, current knowledge about the rejuvenating and repairing somatic stem cells that are distinct from other stem cell types (such as embryonic or induced pluripotent stem cells), emphasize that our body in old age cannot take advantage of these rejuvenating cells, and provide some examples of novel experimental stem cell applications in the field of rejuvenation and antiaging biomedical research.

Aging and stem cell therapy: AMPK as an applicable pharmacological target for rejuvenation of aged stem cells and achieving higher efficacy in stem cell therapy.

Science.gov (United States)

Khorraminejad-Shirazi, Mohammadhossein; Farahmandnia, Mohammad; Kardeh, Bahareh; Estedlal, Alireza; Kardeh, Sina; Monabati, Ahmad

2017-10-19

In recent years, tissue regeneration has become a promising field for developing stem cell-based transplantation therapies for human patients. Adult stem cells are affected by the same aging mechanisms that involve somatic cells. One of the mechanisms involved in cellular aging is hyperactivation of mechanistic target of rapamycin complex 1 (mTORC1) and disruption of 5' adenosine monophosphate-activated protein kinase (AMPK). Aging of stem cells results in their impaired regenerative capacity and depletion of stem cell pools in adult tissue, which results in lower efficacy of stem cell therapy. By utilizing an effective therapeutic intervention for aged stem cells, stem cell therapy can become more promising for future application. mTORC1 inhibition is a practical approach to preserve the stem cell pool. In this article, we review the dynamic interaction between sirtuin (silent mating type information regulation 2 homolog) 1, AMPK, and mTORC1. We propose that using AMPK activators such as 5-aminoimidazole-4-carboxamide ribonucleotide, A769662, metformin, and oxidized nicotinamide adenine dinucleotide (NAD + ) are practical ways to be employed for achieving better optimized results in stem cell-based transplantation therapies. Copyright © 2017 King Faisal Specialist Hospital & Research Centre. Published by Elsevier B.V. All rights reserved.

Mesenchymal Stem Cells

DEFF Research Database (Denmark)

Horwood, Nicole J.; Dazzi, Francesco; Zaher, Walid

2012-01-01

Mesenchymal stem cells (MSC) are stem cell populations present among the bone marrow stroma and a number of other tissues that are capable of multi-lineage differentiation into mesoderm-type cells such as osteoblasts, adipocytes and chondrocytes. MSC provide supportive stroma for growth...... and differentiation of hematopoietic stem cells (HSC) and hematopoiesis. These cells have been described as important immunoregulators due to their ability to suppress T cells proliferation. MSC can also directly contribute to tissue repair by migrating to sites of injury and providing a source of cells...... for differentiation and/or providing bystander support for resident stromal cells. This chapter discusses the cellular and molecular properties of MSC, the mechanisms by which they can modulate immune responses and the clinical applications of MSC in disorders such as graft-versus-host disease and aplastic anaemia...

Stem Cell Lineages: Between Cell and Organism

Directory of Open Access Journals (Sweden)

Melinda Bonnie Fagan

2017-01-01

Full Text Available Ontologies of living things are increasingly grounded on the concepts and practices of current life science. Biological development is a process, undergone by living things, which begins with a single cell and (in an important class of cases ends with formation of a multicellular organism. The process of development is thus prima facie central for ideas about biological individuality and organismality. However, recent accounts of these concepts do not engage developmental biology. This paper aims to fill the gap, proposing the lineage view of stem cells as an ontological framework for conceptualizing organismal development. This account is grounded on experimental practices of stem cell research, with emphasis on new techniques for generating biological organization in vitro. On the lineage view, a stem cell is the starting point of a cell lineage with a specific organismal source, time-interval of existence, and ‘tree topology’ of branch-points linking the stem to developmental termini. The concept of ‘enkapsis’ accommodates the cell-organism relation within the lineage view; this hierarchical notion is further explicated by considering the methods and results of stem cell experiments. Results of this examination include a (partial characterization of stem cells’ developmental versatility, and the context-dependence of developmental processes involving stem cells.

Stem cell plasticity.

Science.gov (United States)

Lakshmipathy, Uma; Verfaillie, Catherine

2005-01-01

The central dogma in stem cell biology has been that cells isolated from a particular tissue can renew and differentiate into lineages of the tissue it resides in. Several studies have challenged this idea by demonstrating that tissue specific cell have considerable plasticity and can cross-lineage restriction boundary and give rise to cell types of other lineages. However, the lack of a clear definition for plasticity has led to confusion with several reports failing to demonstrate that a single cell can indeed differentiate into multiple lineages at significant levels. Further, differences between results obtained in different labs has cast doubt on some results and several studies still await independent confirmation. In this review, we critically evaluate studies that report stem cell plasticity using three rigid criteria to define stem cell plasticity; differentiation of a single cell into multiple cell lineages, functionality of differentiated cells in vitro and in vivo, robust and persistent engraft of transplanted cells.

Characterization and comparison of osteoblasts derived from mouse embryonic stem cells and induced pluripotent stem cells

NARCIS (Netherlands)

Ma, Ming San; Kannan, Vishnu; de Vries, Anneriek E; Czepiel, Marcin; Wesseling, Evelyn; Balasubramaniyan, Veerakumar; Kuijer, Roelof; Vissink, Arjan; Copray, Sjef; Raghoebar, Gerry

New developments in stem cell biology offer alternatives for the reconstruction of critical-sized bone defects. One of these developments is the use of induced pluripotent stem (iPS) cells. These stem cells are similar to embryonic stem (ES) cells, but can be generated from adult somatic cells and

What's missing? Discussing stem cell translational research in educational information on stem cell "tourism".

Science.gov (United States)

Master, Zubin; Zarzeczny, Amy; Rachul, Christen; Caulfield, Timothy

2013-01-01

Stem cell tourism is a growing industry in which patients pursue unproven stem cell therapies for a wide variety of illnesses and conditions. It is a challenging market to regulate due to a number of factors including its international, online, direct-to-consumer approach. Calls to provide education and information to patients, their families, physicians, and the general public about the risks associated with stem cell tourism are mounting. Initial studies examining the perceptions of patients who have pursued stem cell tourism indicate many are highly critical of the research and regulatory systems in their home countries and believe them to be stagnant and unresponsive to patient needs. We suggest that educational material should include an explanation of the translational research process, in addition to other aspects of stem cell tourism, as one means to help promote greater understanding and, ideally, curb patient demand for unproven stem cell interventions. The material provided must stress that strong scientific research is required in order for therapies to be safe and have a greater chance at being effective. Through an analysis of educational material on stem cell tourism and translational stem cell research from patient groups and scientific societies, we describe essential elements that should be conveyed in educational material provided to patients. Although we support the broad dissemination of educational material on stem cell translational research, we also acknowledge that education may simply not be enough to engender patient and public trust in domestic research and regulatory systems. However, promoting patient autonomy by providing good quality information to patients so they can make better informed decisions is valuable in itself, irrespective of whether it serves as an effective deterrent of stem cell tourism. © 2013 American Society of Law, Medicine & Ethics, Inc.

Stem Cell Technology in Cardiac Regeneration: A Pluripotent Stem Cell Promise.

Science.gov (United States)

Duelen, Robin; Sampaolesi, Maurilio

2017-02-01

Despite advances in cardiovascular biology and medical therapy, heart disorders are the leading cause of death worldwide. Cell-based regenerative therapies become a promising treatment for patients affected by heart failure, but also underline the need for reproducible results in preclinical and clinical studies for safety and efficacy. Enthusiasm has been tempered by poor engraftment, survival and differentiation of the injected adult stem cells. The crucial challenge is identification and selection of the most suitable stem cell type for cardiac regenerative medicine. Human pluripotent stem cells (PSCs) have emerged as attractive cell source to obtain cardiomyocytes (CMs), with potential applications, including drug discovery and toxicity screening, disease modelling and innovative cell therapies. Lessons from embryology offered important insights into the development of stem cell-derived CMs. However, the generation of a CM population, uniform in cardiac subtype, adult maturation and functional properties, is highly recommended. Moreover, hurdles regarding tumorigenesis, graft cell death, immune rejection and arrhythmogenesis need to be overcome in clinical practice. Here we highlight the recent progression in PSC technologies for the regeneration of injured heart. We review novel strategies that might overcome current obstacles in heart regenerative medicine, aiming at improving cell survival and functional integration after cell transplantation. Copyright © 2017. Published by Elsevier B.V.

Stem Cell Technology in Cardiac Regeneration: A Pluripotent Stem Cell Promise

Directory of Open Access Journals (Sweden)

Robin Duelen

2017-02-01

Full Text Available Despite advances in cardiovascular biology and medical therapy, heart disorders are the leading cause of death worldwide. Cell-based regenerative therapies become a promising treatment for patients affected by heart failure, but also underline the need for reproducible results in preclinical and clinical studies for safety and efficacy. Enthusiasm has been tempered by poor engraftment, survival and differentiation of the injected adult stem cells. The crucial challenge is identification and selection of the most suitable stem cell type for cardiac regenerative medicine. Human pluripotent stem cells (PSCs have emerged as attractive cell source to obtain cardiomyocytes (CMs, with potential applications, including drug discovery and toxicity screening, disease modelling and innovative cell therapies. Lessons from embryology offered important insights into the development of stem cell-derived CMs. However, the generation of a CM population, uniform in cardiac subtype, adult maturation and functional properties, is highly recommended. Moreover, hurdles regarding tumorigenesis, graft cell death, immune rejection and arrhythmogenesis need to be overcome in clinical practice. Here we highlight the recent progression in PSC technologies for the regeneration of injured heart. We review novel strategies that might overcome current obstacles in heart regenerative medicine, aiming at improving cell survival and functional integration after cell transplantation.

TGF-β superfamily signaling in testis formation and early male germline development.

Science.gov (United States)

Young, Julia C; Wakitani, Shoichi; Loveland, Kate L

2015-09-01

The TGF-β ligand superfamily contains at least 40 members, many of which are produced and act within the mammalian testis to facilitate formation of sperm. Their progressive expression at key stages and in specific cell types determines the fertility of adult males, influencing testis development and controlling germline differentiation. BMPs are essential for the interactive instructions between multiple cell types in the early embryo that drive initial specification of gamete precursors. In the nascent foetal testis, several ligands including Nodal, TGF-βs, Activins and BMPs, serve as key masculinizing switches by regulating male germline pluripotency, somatic and germline proliferation, and testicular vascularization and architecture. In postnatal life, local production of these factors determine adult testis size by regulating Sertoli cell multiplication and differentiation, in addition to specifying germline differentiation and multiplication. Because TGF-β superfamily signaling is integral to testis formation, it affects processes that underlie testicular pathologies, including testicular cancer, and its potential to contribute to subfertility is beginning to be understood. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

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Varga, Nora [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Vereb, Zoltan; Rajnavoelgyi, Eva [Department of Immunology, Medical and Health Science Centre, University of Debrecen, Debrecen (Hungary); Nemet, Katalin; Uher, Ferenc; Sarkadi, Balazs [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary); Apati, Agota, E-mail: apati@kkk.org.hu [Membrane Research Group of the Hungarian Academy of Sciences, Semmelweis University, Budapest (Hungary)

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.

Generation of induced pluripotent stem cell-derived mice by reprogramming of a mature NKT cell.

Science.gov (United States)

Ren, Yue; Dashtsoodol, Nyambayar; Watarai, Hiroshi; Koseki, Haruhiko; Quan, Chengshi; Taniguchi, Masaru

2014-10-01

NKT cells are characterized by their expression of an NKT-cell-specific invariant antigen-receptor α chain encoded by Vα14Jα18 gene segments. These NKT cells bridge the innate and acquired immune systems to mediate effective and augmented responses; however, the limited number of NKT cells in vivo hampers their analysis. Here, two lines of induced pluripotent stem cell-derived mice (NKT-iPSC-derived mice) were generated by reprogramming of mature NKT cells, where one harbors both rearranged Vα14Jα18 and Vβ7 genes and the other carries rearranged Vα14Jα18 on both alleles but germline Vβ loci. The analysis of NKT-iPSC-derived mice showed a significant increase in NKT cell numbers with relatively normal frequencies of functional subsets, but significantly enhanced in some cases, and acquired functional NKT cell maturation in peripheral lymphoid organs. NKT-iPSC-derived mice also showed normal development of other immune cells except for the absence of γδT cells and disturbed development of conventional CD4 αβT cells. These results suggest that the NKT-iPSC-derived mice are a better model for NKT cell development and function study rather than transgenic mouse models reported previously and also that the presence of a pre-rearranged Vα14Jα18 in the natural chromosomal context favors the developmental fate of NKT cells. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society for Immunology.

Systems Biology and Stem Cell Pluripotency

DEFF Research Database (Denmark)

Mashayekhi, Kaveh; Hall, Vanessa Jane; Freude, Kristine

2016-01-01

Recent breakthroughs in stem cell biology have accelerated research in the area of regenerative medicine. Over the past years, it has become possible to derive patient-specific stem cells which can be used to generate different cell populations for potential cell therapy. Systems biological...... modeling of stem cell pluripotency and differentiation have largely been based on prior knowledge of signaling pathways, gene regulatory networks, and epigenetic factors. However, there is a great need to extend the complexity of the modeling and to integrate different types of data, which would further...... improve systems biology and its uses in the field. In this chapter, we first give a general background on stem cell biology and regenerative medicine. Stem cell potency is introduced together with the hierarchy of stem cells ranging from pluripotent embryonic stem cells (ESCs) and induced pluripotent stem...

Engineering Stem Cells for Biomedical Applications

Science.gov (United States)

Yin, Perry T.; Han, Edward

2018-01-01

Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer. PMID:25772134

Engineering Stem Cells for Biomedical Applications.

Science.gov (United States)

Yin, Perry T; Han, Edward; Lee, Ki-Bum

2016-01-07

Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

International Society for Stem Cell Research

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... renowned stem cell and regenerative medicine community. More stem cell research Take a closer look Recent Blogs View ... story independent nonprofit organization & the voice of the stem cell research community The International Society for Stem Cell ...

Eckol suppresses maintenance of stemness and malignancies in glioma stem-like cells

International Nuclear Information System (INIS)

Hyun, Kyung-Hwan; Yoon, Chang-Hwan; Kim, Rae-Kwon; Lim, Eun-Jung; An, Sungkwan; Park, Myung-Jin; Hyun, Jin-Won; Suh, Yongjoon; Kim, Min-Jung; Lee, Su-Jae

2011-01-01

A subpopulation of cancer cells with stem cell properties is responsible for tumor maintenance and progression, and may contribute to resistance to anticancer treatments. Thus, compounds that target cancer stem-like cells could be usefully applied to destroy cancer. In this study, we investigated the effect of Eckol, a phlorotannin compound, on stemness and malignancies in glioma stem-like cells. To determine whether Eckol targets glioma stem-like cells, we examined whether Eckol treatment could change the expression levels of glioma stem-like cell markers and self-renewal-related proteins as well as the sphere forming ability, and the sensitivity to anticancer treatments. Alterations in the malignant properties of sphere-derived cells by Eckol were also investigated by soft-agar colony forming assay, by xenograft assay in nude mice, and by cell invasion assay. Treatment of sphere-forming glioma cells with Eckol effectively decreased the sphere formation as well as the CD133 + cell population. Eckol treatment suppressed expression of the glioma stem-like cell markers and the self-renewal-related proteins without cell death. Moreover, treatment of glioma stem-like cells with Eckol significantly attenuated anchorage-independent growth on soft agar and tumor formation in xenograft mice. Importantly, Eckol treatment effectively reduced the resistance of glioma stem-like cells to ionizing radiation and temozolomide. Treatment of glioma stem-like cells with Eckol markedly blocked both phosphoinositide 3-kinase-Akt and Ras-Raf-1-Erk signaling pathways. These results indicate that the natural phlorotannin Eckol suppresses stemness and malignancies in glioma stem-like cells, and thereby makes glioma stem-like cells more sensitive to anticancer treatments, providing novel therapeutic strategies targeting specifically cancer stem-like cells.

Stem Cells in Burn Eschar

NARCIS (Netherlands)

van der Veen, V. C.; Vlig, M.; van Milligen-Kummer, F.J.; de Vries, S.I.; Middelkoop, E.; Ulrich, M.

2012-01-01

This study compares mesenchymal cells isolated from excised burn wound eschar with adipose-derived stem cells (ASCs) and dermal fibroblasts in their ability to conform to the requirements for multipotent mesenchymal stem cells (MSCs). A population of multipotent stem cells in burn eschar could be an

Stem Cell Transplants (For Teens)

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... Safe Videos for Educators Search English Español Stem Cell Transplants KidsHealth / For Teens / Stem Cell Transplants What's ... Take to Recover? Coping Print What Are Stem Cells? As you probably remember from biology class, every ...

[Progress in stem cells and regenerative medicine].

Science.gov (United States)

Wang, Libin; Zhu, He; Hao, Jie; Zhou, Qi

2015-06-01

Stem cells have the ability to differentiate into all types of cells in the body and therefore have great application potential in regenerative medicine, in vitro disease modelling and drug screening. In recent years, stem cell technology has made great progress, and induced pluripotent stem cell technology revolutionizes the whole stem cell field. At the same time, stem cell research in our country has also achieved great progress and becomes an indispensable power in the worldwide stem cell research field. This review mainly focuses on the research progress in stem cells and regenerative medicine in our country since the advent of induced pluripotent stem cell technology, including induced pluripotent stem cells, transdifferentiation, haploid stem cells, and new gene editing tools.

Stem cell organization in Arabidopsis

NARCIS (Netherlands)

Wendrich, J.R.

2016-01-01

Growth of plant tissues and organs depends on continuous production of new cells, by niches of stem cells. Stem cells typically divide to give rise to one differentiating daughter and one non-differentiating daughter. This constant process of self-renewal ensures that the niches of stem cells or

Stem cells and cancer: A review

Directory of Open Access Journals (Sweden)

Najeeb Ullah

2016-05-01

Full Text Available Stem cells are the small units of multicellular creature. Regeneration and self-renewal are the ability of the stem cells. Each tissue is having particular stem cells, specific to it. These normal stem cells are converted into cancer stem cells through mutations in it. Although the expression of oncogenes is enhanced a lot, the tumor-supressing gene is lessened. Cancer stem cells are isolated and visualized through different techniques like immunocytochemical staining, spectral karyotyping, immunohistochemistry, induction method and dissection measures, then are performed histological procedures which include fascination, immunohistochemistry, dispensation, in situ hybridization and also quantitative examination of tissue flow cytometric analysis. For the analysis of quantization, statistical tests are also performed as two-sample t-test, Chi-square test, SD and arithmetic mean. Tumor cells generate glioma spheres. These are used in cancer study. Axin 1 is the gene suppressing cancer. Its removal causes the generation of liver cancer. Curcumin is the most effective for suppressing cancer as it increases the normal stem cell function and decreases the cancer stem cell function. Brahma-related gene 1 is crucial for the safeguarding of the stem cell residents in tissue-specific comportment. Different types of cancers originate through genetic mutation, tissue disorganization and cell proliferation. Tumor configuration is produced by the alteration in original cell culture having stem cells and progenitor cell populations. The developmental facets about cancer cells and cancer stem cells as well as their personal natal functions sustain an intricate steadiness to settle on their personal donations to the efficacy or harmfulness of the biological organization.

Selfish genetic elements favor the evolution of a distinction between soma and germline.

Science.gov (United States)

Johnson, Louise J

2008-08-01

Many multicellular organisms have evolved a dedicated germline. This can benefit the whole organism, but its advantages to genetic parasites have not been explored. Here I model the evolutionary success of a selfish element, such as a transposable element or endosymbiont, which is capable of creating or strengthening a germline-soma distinction in a primitively multicellular host, and find that it will always benefit the element to do so. Genes causing germline sequestration can therefore spread in a population even if germline sequestration is maladaptive for the host organism. Costly selfish elements are expected to survive only in sexual populations, so sexual species may experience an additional push toward germline-soma distinction, and hence toward cell differentiation and multicellularity.

Stem Cell Information: Glossary

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... Tips Info Center Research Topics Federal Policy Glossary Stem Cell Information General Information Clinical Trials Funding Information Current ... here Home » Glossary Back to top Glossary Adult stem cell Astrocyte Blastocoel Blastocyst Bone marrow stromal cells Bone ...

Pluripotent stem cells and reprogrammed cells in farm animals.

Science.gov (United States)

Nowak-Imialek, Monika; Kues, Wilfried; Carnwath, Joseph W; Niemann, Heiner

2011-08-01

Pluripotent cells are unique because of their ability to differentiate into the cell lineages forming the entire organism. True pluripotent stem cells with germ line contribution have been reported for mice and rats. Human pluripotent cells share numerous features of pluripotentiality, but confirmation of their in vivo capacity for germ line contribution is impossible due to ethical and legal restrictions. Progress toward derivation of embryonic stem cells from domestic species has been made, but the derived cells were not able to produce germ line chimeras and thus are termed embryonic stem-like cells. However, domestic animals, in particular the domestic pig (Sus scrofa), are excellent large animals models, in which the clinical potential of stem cell therapies can be studied. Reprogramming technologies for somatic cells, including somatic cell nuclear transfer, cell fusion, in vitro culture in the presence of cell extracts, in vitro conversion of adult unipotent spermatogonial stem cells into germ line derived pluripotent stem cells, and transduction with reprogramming factors have been developed with the goal of obtaining pluripotent, germ line competent stem cells from domestic animals. This review summarizes the present state of the art in the derivation and maintenance of pluripotent stem cells in domestic animals.

Information on Stem Cell Research

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... Home » Current Research » Focus on Research Focus on Stem Cell Research Stem cells possess the unique ability to differentiate into ... virus infection. To search the complete list of stem cell research projects funded by NIH please go to NIH ...

Donating Peripheral Blood Stem Cells

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... Print this page My Cart Donating peripheral blood stem cells Peripheral blood stem cell (PBSC) donation is a nonsurgical procedure to collect ... Donating bone marrow Donor experiences videos Peripheral blood stem cell (PBSC) donation is one of two methods of ...

Germline fumarate hydratase mutations in patients with ovarian mucinous cystadenoma

DEFF Research Database (Denmark)

Ylisaukko-oja, Sanna K.; Cybulski, Cezary; Lehtonen, Rainer

2006-01-01

Germline mutations in the fumarate hydratase (FH) gene were recently shown to predispose to the dominantly inherited syndrome, hereditary leiomyomatosis and renal cell cancer (HLRCC). HLRCC is characterized by benign leiomyomas of the skin and the uterus, renal cell carcinoma, and uterine...... leiomyosarcoma. The aim of this study was to identify new families with FH mutations, and to further examine the tumor spectrum associated with FH mutations. FH germline mutations were screened from 89 patients with RCC, skin leiomyomas or ovarian tumors. Subsequently, 13 ovarian and 48 bladder carcinomas were...

Bioprinting for stem cell research

Science.gov (United States)

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

Turnover of circulating hematopoietic stem cells

Energy Technology Data Exchange (ETDEWEB)

Dorie, M J; Maloney, M A; Patt, H M

1979-10-01

Short-term parabiosis of male and female CBA/CaJ mice was used to investigate the turnover of circulating hematopoietic stem cells. The change and subsequent disappearance of donor stem cells were monitored by spleen colony assay and chromosome analysis of individual colonies. The results revealed an exponential disappearance of pluripotent stem cells from blood with a characteristic half time of 1.7 h. Blood-borne stem cells were shown to be equilibrated with a subpopulation of marrow stem cells exhibiting a disappearance half time of 9.5 h. Splenectomy did not change the apparent rate of stem cell removal from the blood.

[Bioethical challenges of stem cell tourism].

Science.gov (United States)

Ventura-Juncá, Patricio; Erices, Alejandro; Santos, Manuel J

2013-08-01

Stem cells have drawn extraordinary attention from scientists and the general public due to their potential to generate effective therapies for incurable diseases. At the same time, the production of embryonic stem cells involves a serious ethical issue concerning the destruction of human embryos. Although adult stem cells and induced pluripotential cells do not pose this ethical objection, there are other bioethical challenges common to all types of stem cells related particularly to the clinical use of stem cells. Their clinical use should be based on clinical trials, and in special situations, medical innovation, both of which have particular ethical dimensions. The media has raised unfounded expectations in patients and the public about the real clinical benefits of stem cells. At the same time, the number of unregulated clinics is increasing around the world, making direct offers through Internet of unproven stem cell therapies that attract desperate patients that have not found solutions in standard medicine. This is what is called stem cells tourism. This article reviews this situation, its consequences and the need for international cooperation to establish effective regulations to prevent the exploitation of patients and to endanger the prestige of legitimate stem cell research.

Therapeutic application of multipotent stem cells

DEFF Research Database (Denmark)

Mirzaei, Hamed; Sahebkar, Amirhossein; Sichani, Laleh Shiri

2018-01-01

Cell therapy is an emerging fields in the treatment of various diseases such as cardiovascular, pulmonary, hepatic, and neoplastic diseases. Stem cells are an integral tool for cell therapy. Multipotent stem cells are an important class of stem cells which have the ability to self-renew through...... been showed that multipotent stem cells exert their therapeutic effects via inhibition/activation of a sequence of cellular and molecular pathways. Although the advantages of multipotent stem cells are numerous, further investigation is still necessary to clarify the biology and safety of these cells...... before they could be considered as a potential treatment for different types of diseases. This review summarizes different features of multipotent stem cells including isolation, differentiation, and therapeutic applications....

Lasers, stem cells, and COPD

Directory of Open Access Journals (Sweden)

De Necochea-Campion Rosalia

2010-02-01

Full Text Available Abstract The medical use of low level laser (LLL irradiation has been occurring for decades, primarily in the area of tissue healing and inflammatory conditions. Despite little mechanistic knowledge, the concept of a non-invasive, non-thermal intervention that has the potential to modulate regenerative processes is worthy of attention when searching for novel methods of augmenting stem cell-based therapies. Here we discuss the use of LLL irradiation as a "photoceutical" for enhancing production of stem cell growth/chemoattractant factors, stimulation of angiogenesis, and directly augmenting proliferation of stem cells. The combination of LLL together with allogeneic and autologous stem cells, as well as post-mobilization directing of stem cells will be discussed.

The Emerging Cell Biology of Thyroid Stem Cells

Science.gov (United States)

Latif, Rauf; Minsky, Noga C.; Ma, Risheng

2011-01-01

Context: Stem cells are undifferentiated cells with the property of self-renewal and give rise to highly specialized cells under appropriate local conditions. The use of stem cells in regenerative medicine holds great promise for the treatment of many diseases, including those of the thyroid gland. Evidence Acquisition: This review focuses on the progress that has been made in thyroid stem cell research including an overview of cellular and molecular events (most of which were drawn from the period 1990–2011) and discusses the remaining problems encountered in their differentiation. Evidence Synthesis: Protocols for the in vitro differentiation of embryonic stem cells, based on normal developmental processes, have generated thyroid-like cells but without full thyrocyte function. However, agents have been identified, including activin A, insulin, and IGF-I, which are able to stimulate the generation of thyroid-like cells in vitro. In addition, thyroid stem/progenitor cells have been identified within the normal thyroid gland and within thyroid cancers. Conclusions: Advances in thyroid stem cell biology are providing not only insight into thyroid development but may offer therapeutic potential in thyroid cancer and future thyroid cell replacement therapy. PMID:21778219

Periarteriolar Glioblastoma Stem Cell Niches Express Bone Marrow Hematopoietic Stem Cell Niche Proteins

NARCIS (Netherlands)

Hira, Vashendriya V. V.; Wormer, Jill R.; Kakar, Hala; Breznik, Barbara; van der Swaan, Britt; Hulsbos, Renske; Tigchelaar, Wikky; Tonar, Zbynek; Khurshed, Mohammed; Molenaar, Remco J.; van Noorden, Cornelis J. F.

2018-01-01

In glioblastoma, a fraction of malignant cells consists of therapy-resistant glioblastoma stem cells (GSCs) residing in protective niches that recapitulate hematopoietic stem cell (HSC) niches in bone marrow. We have previously shown that HSC niche proteins stromal cell-derived factor-1α (SDF-1α),

Stem cells in pharmaceutical biotechnology.

Science.gov (United States)

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

HPV-Induced Field Cancerisation: Transformation of Adult Tissue Stem Cell Into Cancer Stem Cell.

Science.gov (United States)

Olivero, Carlotta; Lanfredini, Simone; Borgogna, Cinzia; Gariglio, Marisa; Patel, Girish K

2018-01-01

Field cancerisation was originally described as a basis for multiple head and neck squamous cell carcinoma (HNSCC) and is a pre-malignant phenomenon that is frequently attributable to oncogenic human papillomavirus (HPV) infection. Our work on β-HPV-induced cutaneous squamous cell carcinomas identified a novel Lrig1+ hair follicle junctional zone keratinocyte stem cell population as the basis for field cancerisation. Herein, we describe the ability for HPV to infect adult tissue stem cells in order to establish persistent infection and induce their proliferation and displacement resulting in field cancerisation. By review of the HPV literature, we reveal how this mechanism is conserved as the basis of field cancerisation across many tissues. New insights have identified the capacity for HPV early region genes to dysregulate adult tissue stem cell self-renewal pathways ensuring that the expanded population preserve its stem cell characteristics beyond the stem cell niche. HPV-infected cells acquire additional transforming mutations that can give rise to intraepithelial neoplasia (IEN), from environmental factors such as sunlight or tobacco induced mutations in skin and oral cavity, respectively. With establishment of IEN, HPV viral replication is sacrificed with loss of the episome, and the tissue is predisposed to multiple cancer stem cell-driven carcinomas.

The Stem Cell Club: a model for unrelated stem cell donor recruitment.

Science.gov (United States)

Fingrut, Warren; Parmar, Simran; Cuperfain, Ari; Rikhraj, Kiran; Charman, Erin; Ptak, Emilie; Kahlon, Manjot; Graham, Alice; Luong, Susan; Wang, Yongjun George; Yu, Janice; Arora, Neha; Suppiah, Roopa; Li, Edward W; Lee, Anna; Welsh, Christopher; Benzaquen, Menachem; Thatcher, Alicia; Baharmand, Iman; Ladd, Aedan; Petraszko, Tanya; Allan, David; Messner, Hans

2017-12-01

Patients with blood, immune, or metabolic diseases may require a stem cell transplant as part of their treatment. However, 70% of patients do not have a suitable human leukocyte antigen match in their family, and need an unrelated donor. Individuals can register as potential donors at stem cell drives, where they provide consent and a tissue sample for human leukocyte antigen typing. The ideal donors are young, male, and from a diversity of ethnic backgrounds. However, in Canada, non-Caucasian males ages 17 to 35 years represent only 8.8% of listed donors. The Stem Cell Club is a non-profit organization founded in 2011 in Canada that aims to augment recruitment of the most needed donors. The initiative published a recruitment toolkit online (www.stemcellclub.ca). Currently, there are 12 chapters at universities across Canada. To date, the Stem Cell Club has recruited 6585 potential registrants, representing 1.63% of donors on Canada's donor-database. Of the recruited registrants, 58.3% were male; 60.3% of males self-reported as non-Caucasian, and 78.5% were ages 17 to 25 years. From 2015 to 2016, the initiative recruited 13.7% of all ethnically diverse males ages 17 to 35 years listed in Canada's donor database. Data from this initiative demonstrate sustainability and performance on key indicators of stem cell drive quality. The Stem Cell Club has developed a capacity to recruit 2600 donors annually, with the majority being males with a high degree of ethnic diversity. The initiative enhances the quality of Canada's unrelated donor-database, improving the chances that patients in need of an unrelated donor will find a match for transplant. The Stem Cell Club is a model relevant to recruitment organizations around the world. © 2017 AABB.

Flow cytometry sorting of nuclei enables the first global characterization of Paramecium germline DNA and transposable elements.

Science.gov (United States)

Guérin, Frédéric; Arnaiz, Olivier; Boggetto, Nicole; Denby Wilkes, Cyril; Meyer, Eric; Sperling, Linda; Duharcourt, Sandra

2017-04-26

DNA elimination is developmentally programmed in a wide variety of eukaryotes, including unicellular ciliates, and leads to the generation of distinct germline and somatic genomes. The ciliate Paramecium tetraurelia harbors two types of nuclei with different functions and genome structures. The transcriptionally inactive micronucleus contains the complete germline genome, while the somatic macronucleus contains a reduced genome streamlined for gene expression. During development of the somatic macronucleus, the germline genome undergoes massive and reproducible DNA elimination events. Availability of both the somatic and germline genomes is essential to examine the genome changes that occur during programmed DNA elimination and ultimately decipher the mechanisms underlying the specific removal of germline-limited sequences. We developed a novel experimental approach that uses flow cell imaging and flow cytometry to sort subpopulations of nuclei to high purity. We sorted vegetative micronuclei and macronuclei during development of P. tetraurelia. We validated the method by flow cell imaging and by high throughput DNA sequencing. Our work establishes the proof of principle that developing somatic macronuclei can be sorted from a complex biological sample to high purity based on their size, shape and DNA content. This method enabled us to sequence, for the first time, the germline DNA from pure micronuclei and to identify novel transposable elements. Sequencing the germline DNA confirms that the Pgm domesticated transposase is required for the excision of all ~45,000 Internal Eliminated Sequences. Comparison of the germline DNA and unrearranged DNA obtained from PGM-silenced cells reveals that the latter does not provide a faithful representation of the germline genome. We developed a flow cytometry-based method to purify P. tetraurelia nuclei to high purity and provided quality control with flow cell imaging and high throughput DNA sequencing. We identified 61

Vitamin C induces specific demethylation of H3K9me2 in mouse embryonic stem cells via Kdm3a/b.

Science.gov (United States)

Ebata, Kevin T; Mesh, Kathryn; Liu, Shichong; Bilenky, Misha; Fekete, Alexander; Acker, Michael G; Hirst, Martin; Garcia, Benjamin A; Ramalho-Santos, Miguel

2017-01-01

Histone methylation patterns regulate gene expression and are highly dynamic during development. The erasure of histone methylation is carried out by histone demethylase enzymes. We had previously shown that vitamin C enhances the activity of Tet enzymes in embryonic stem (ES) cells, leading to DNA demethylation and activation of germline genes. We report here that vitamin C induces a remarkably specific demethylation of histone H3 lysine 9 dimethylation (H3K9me2) in naïve ES cells. Vitamin C treatment reduces global levels of H3K9me2, but not other histone methylation marks analyzed, as measured by western blot, immunofluorescence and mass spectrometry. Vitamin C leads to widespread loss of H3K9me2 at large chromosomal domains as well as gene promoters and repeat elements. Vitamin C-induced loss of H3K9me2 occurs rapidly within 24 h and is reversible. Importantly, we found that the histone demethylases Kdm3a and Kdm3b are required for vitamin C-induced demethylation of H3K9me2. Moreover, we show that vitamin C-induced Kdm3a/b-mediated H3K9me2 demethylation and Tet-mediated DNA demethylation are independent processes at specific loci. Lastly, we document Kdm3a/b are partially required for the upregulation of germline genes by vitamin C. These results reveal a specific role for vitamin C in histone demethylation in ES cells and document that DNA methylation and H3K9me2 cooperate to silence germline genes in pluripotent cells.

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

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Hilary Jane Anderson

2016-05-01

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

Deadenylase depletion protects inherited mRNAs in primordial germ cells.

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Swartz, S Zachary; Reich, Adrian M; Oulhen, Nathalie; Raz, Tal; Milos, Patrice M; Campanale, Joseph P; Hamdoun, Amro; Wessel, Gary M

2014-08-01

A crucial event in animal development is the specification of primordial germ cells (PGCs), which become the stem cells that create sperm and eggs. How PGCs are created provides a valuable paradigm for understanding stem cells in general. We find that the PGCs of the sea urchin Strongylocentrotus purpuratus exhibit broad transcriptional repression, yet enrichment for a set of inherited mRNAs. Enrichment of several germline determinants in the PGCs requires the RNA-binding protein Nanos to target the transcript that encodes CNOT6, a deadenylase, for degradation in the PGCs, thereby creating a stable environment for RNA. Misexpression of CNOT6 in the PGCs results in their failure to retain Seawi transcripts and Vasa protein. Conversely, broad knockdown of CNOT6 expands the domain of Seawi RNA as well as exogenous reporters. Thus, Nanos-dependent spatially restricted CNOT6 differential expression is used to selectively localize germline RNAs to the PGCs. Our findings support a 'time capsule' model of germline determination, whereby the PGCs are insulated from differentiation by retaining the molecular characteristics of the totipotent egg and early embryo. © 2014. Published by The Company of Biologists Ltd.

Seeding of single hemopoietic stem cells and self renewal of committed stem cells

International Nuclear Information System (INIS)

Brecher, G.

1986-01-01

Single cells and two to five proliferating cells were transfused into mice whose own stem cells had been killed by irradiation. When a small inoculum of 50,000 AB marrow cells was given only 4 of 20 recipients survived, but all 4 had only PGK A enzyme in their peripheral blood cells. The results indicate that the survivors received a single pluripotential stem cell capable of proliferating. Survivors showed no deterioration in their blood picture after many months. It was concluded that there is no clonal succession in the marrow cells. Further studies with transfusions of 100,000 and 10,000,000 marrow cells after lethal irradiation suggest that there is production of committed stem cells with significant self-renewal

Germ cell transplantation using sexually competent fish: an approach for rapid propagation of endangered and valuable germlines.

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Sullip K Majhi

Full Text Available The transplantation of germ cells into adult recipient gonads is a tool with wide applications in animal breeding and conservation of valuable and/or endangered species; it also provides a means for basic studies involving germ cell (GC proliferation and differentiation. Here we describe the establishment of a working model for xenogeneic germ cell transplantation (GCT in sexually competent fish. Spermatogonial cells isolated from juveniles of one species, the pejerrey Odontesthes bonariensis (Atherinopsidae, were surgically transplanted into the gonads of sexually mature Patagonian pejerrey O. hatcheri, which have been partially depleted of endogenous GCs by a combination of Busulfan (40 mg/kg and high water temperature (25 degrees C treatments. The observation of the donor cells' behavior showed that transplanted spermatogonial cells were able to recolonize the recipients' gonads and resume spermatogenesis within 6 months from the GCT. The presence of donor-derived gametes was confirmed by PCR in 20% of the surrogate O. hatcheri fathers at 6 months and crosses with O. bonariensis mothers produced hybrids and pure O. bonariensis, with donor-derived germline transmission rates of 1.2-13.3%. These findings indicate that transplantation of spermatogonial cells into sexually competent fish can shorten considerably the production time of donor-derived gametes and offspring and could play a vital role in germline conservation and propagation of valued and/or endangered fish species.

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

Science.gov (United States)

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

2014-01-01

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

Stem Cell-Based Therapies for Ischemic Stroke

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Lei Hao

2014-01-01

Full Text Available In recent years, stem cell-based approaches have attracted more attention from scientists and clinicians due to their possible therapeutical effect on stroke. Animal studies have demonstrated that the beneficial effects of stem cells including embryonic stem cells (ESCs, inducible pluripotent stem cells (iPSCs, neural stem cells (NSCs, and mesenchymal stem cell (MSCs might be due to cell replacement, neuroprotection, endogenous neurogenesis, angiogenesis, and modulation on inflammation and immune response. Although several clinical studies have shown the high efficiency and safety of stem cell in stroke management, mainly MSCs, some issues regarding to cell homing, survival, tracking, safety, and optimal cell transplantation protocol, such as cell dose and time window, should be addressed. Undoubtably, stem cell-based gene therapy represents a novel potential therapeutic strategy for stroke in future.

Autophagy in Stem Cell Biology: A Perspective on Stem Cell Self-Renewal and Differentiation

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Xihang Chen

2018-01-01

Full Text Available Autophagy is a highly conserved cellular process that degrades modified, surplus, or harmful cytoplasmic components by sequestering them in autophagosomes which then fuses with the lysosome for degradation. As a major intracellular degradation and recycling pathway, autophagy is crucial for maintaining cellular homeostasis, as well as for remodeling during normal development. Impairment of this process has been implicated in various diseases, in the pathogenic response to bacterial and viral infections, and in aging. Pluripotent stem cells, with their ability to self-replicate and to give rise to any specialized cell type, are very valuable resources for cell-based medical therapies and open a number of promising avenues for studying human development and disease. It has been suggested that autophagy is vital for the maintenance of cellular homeostasis in stem cells, and subsequently more in-depth knowledge about the regulation of autophagy in stem cell biology has been acquired recently. In this review, we describe the most significant advances in the understanding of autophagy regulation in hematopoietic and mesenchymal stem cells, as well as in induced pluripotent stem cells. In particular, we highlight the roles of various autophagy activities in the regulation of self-renewal and differentiation of these stem cells.

Nuclear Mechanics and Stem Cell Differentiation.

Science.gov (United States)

Mao, Xinjian; Gavara, Nuria; Song, Guanbin

2015-12-01

Stem cells are characterized by their self-renewal and multi-lineage differentiation potential. Stem cell differentiation is a prerequisite for the application of stem cells in regenerative medicine and clinical therapy. In addition to chemical stimulation, mechanical cues play a significant role in regulating stem cell differentiation. The integrity of mechanical sensors is necessary for the ability of cells to respond to mechanical signals. The nucleus, the largest and stiffest cellular organelle, interacts with the cytoskeleton as a key mediator of cell mechanics. Nuclear mechanics are involved in the complicated interactions of lamins, chromatin and nucleoskeleton-related proteins. Thus, stem cell differentiation is intimately associated with nuclear mechanics due to its indispensable role in mechanotransduction and mechanical response. This paper reviews several main contributions of nuclear mechanics, highlights the hallmarks of the nuclear mechanics of stem cells, and provides insight into the relationship between nuclear mechanics and stem cell differentiation, which may guide clinical applications in the future.

Stem Cell Therapy: An emerging science

International Nuclear Information System (INIS)

Khan, Muhammad M.

2007-01-01

The research on stem cells is advancing knowledge about the development of an organism from a single cell and to how healthy cells replace damaged cells in adult organisms. Stem cell therapy is emerging rapidly nowadays as a technical tool for tissue repair and replacement. The purpose of this review to provide a framework of understanding for the challenges behind translating fundamental stem cell biology and its potential use into clinical therapies, also to give an overview on stem cell research to the scientists of Saudi Arabia in general. English language MEDLINE publications from 1980 through January 2007 for experimental, observational and clinical studies having relation with stem cells with different diseases were reviewed. Approximately 85 publications were reviewed based on the relevance, strength and quality of design and methods, 36 publications were selected for inclusion. Stem cells reside in a specific area of each tissue where they may remain undivided for several years until they are activated by disease or tissue injury. The embryonic stem cells are typically derived from four or five days old embryos and they are pluripotent. The adult tissues reported to contain stem cells brain, bone marrow, peripheral blood, blood vessels, skeletal muscle, skin and liver. The promise of stem cell therapies is an exciting one, but significant technical hurdles remain that will only be overcome through years of intensive research. (author)

The pluripotency of hair follicle stem cells.

Science.gov (United States)

Hoffman, Robert M

2006-02-01

The hair follicle bulge area is an abundant, easily accessible source of actively growing, pluripotent adult stem cells. Nestin, a protein marker for neural stem cells, is also expressed in follicle stem cells as well as their immediate differentiated progeny. The nestin-expressing hair follicle stem cells differentiated into neurons, glial cells, keratinocytes and smooth muscle cells in vitro. Hair-follicle stem cells were implanted into the gap region of a severed sciatic nerve. The hair follicle stem cells greatly enhanced the rate of nerve regeneration and the restoration of nerve function. The follicle stem cells transdifferentiated largely into Schwann cells which are known to support neuron regrowth. Function of the rejoined sciatic nerve was measured by contraction of the gastrocnemius muscle upon electrical stimulation. After severing the tibial nerve and subsequent transplantation of hair-follicle stem cells, the transplanted mice recovered the ability to walk normally. These results suggest that hair-follicle stem cells provide an important accessible, autologous source of adult stem cells for regenerative medicine.

Multifaceted Interpretation of Colon Cancer Stem Cells.

Science.gov (United States)

Hatano, Yuichiro; Fukuda, Shinya; Hisamatsu, Kenji; Hirata, Akihiro; Hara, Akira; Tomita, Hiroyuki

2017-07-05

Colon cancer is one of the leading causes of cancer-related deaths worldwide, despite recent advances in clinical oncology. Accumulating evidence sheds light on the existence of cancer stem cells and their role in conferring therapeutic resistance. Cancer stem cells are a minor fraction of cancer cells, which enable tumor heterogeneity and initiate tumor formation. In addition, these cells are resistant to various cytotoxic factors. Therefore, elimination of cancer stem cells is difficult but essential to cure the malignant foci completely. Herein, we review the recent evidence for intestinal stem cells and colon cancer stem cells, methods to detect the tumor-initiating cells, and clinical significance of cancer stem cell markers. We also describe the emerging problems of cancer stem cell theory, including bidirectional conversion and intertumoral heterogeneity of stem cell phenotype.

Aneuploidy in stem cells

NARCIS (Netherlands)

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

Dazlin' pluripotent stem cells

NARCIS (Netherlands)

Welling, M.A.

2014-01-01

Pluripotent embryonic stem cells (ESCs) can be isolated from the inner cell mass (ICM) of blastocyst embryos and differentiate into all three germ layers in vitro. However, despite their similar origin, mouse embryonic stem cells represent a more naïve ICM-like pluripotent state whereas human

Mammary gland stem cells

DEFF Research Database (Denmark)

Fridriksdottir, Agla J R; Petersen, Ole W; Rønnov-Jessen, Lone

2011-01-01

Distinct subsets of cells, including cells with stem cell-like properties, have been proposed to exist in normal human breast epithelium and breast carcinomas. The cellular origins of epithelial cells contributing to gland development, tissue homeostasis and cancer are, however, still poorly...... and differences between mouse and human gland development with particular emphasis on the identity and localization of stem cells, and the influence of the surrounding microenvironment. It is concluded that while recent advances in the field have contributed immense insight into how the normal mammary gland...... develops and is maintained, significant discrepancies exist between the mouse and human gland which should be taken into consideration in current and future models of mammary stem cell biology....

Stem Cells and Herbal Acupuncture Therapy

Directory of Open Access Journals (Sweden)

Ki Rok Kwon

2005-12-01

Full Text Available Stem cell therapy implies the birth of regenerative medicine. Regenerative medicine signify treatment through regeneration of cells which was impossible by existing medicine. Stem cell is classified into embryonic stem cell and adult stem cell and they have distinctive benefits and limitations. Researches on stem cell are already under active progression and is expected to be commercially available in the near future. One may not relate the stem cell treatment with Oriental medicine, but can be interpreted as the fundamental treatment action of Oriental medicine is being investigated in more concrete manner. When it comes to difficult to cure diseases, there is no boundary between eastern and western medicine, and one must be ready to face and overcome changes lying ahead.

Mesenchymal to Epithelial Transition Mediated by CDH1 Promotes Spontaneous Reprogramming of Male Germline Stem Cells to Pluripotency

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Junhui An

2017-02-01

Full Text Available Cultured spermatogonial stem cells (GSCs can spontaneously form pluripotent cells in certain culture conditions. However, GSC reprogramming is a rare event that is largely unexplained. We show GSCs have high expression of mesenchymal to epithelial transition (MET suppressors resulting in a developmental barrier inhibiting GSC reprogramming. Either increasing OCT4 or repressing transforming growth factor β (TGF-β signaling promotes GSC reprogramming by upregulating CDH1 and boosting MET. Reducing ZEB1 also enhances GSC reprogramming through its direct effect on CDH1. RNA sequencing shows that rare GSCs, identified as CDH1+ after trypsin digestion, are epithelial-like cells. CDH1+ GSCs exhibit enhanced reprogramming and become more prevalent during the course of reprogramming. Our results provide a mechanistic explanation for the spontaneous emergence of pluripotent cells from GSC cultures; namely, rare GSCs upregulate CDH1 and initiate MET, processes normally kept in check by ZEB1 and TGF-β signaling, thereby ensuring germ cells are protected from aberrant acquisition of pluripotency.

Therapeutic potential of adult stem cells

DEFF Research Database (Denmark)

Serakinci, Nedime; Keith, W. Nicol

2006-01-01

is the necessity to be able to identify, select, expand and manipulate cells outside the body. Recent advances in adult stem cell technologies and basic biology have accelerated therapeutic opportunities aimed at eventual clinical applications. Adult stem cells with the ability to differentiate down multiple...... lineages are an attractive alternative to human embryonic stem cells (hES) in regenerative medicine. In many countries, present legislation surrounding hES cells makes their use problematic, and indeed the origin of hES cells may represent a controversial issue for many communities. However, adult stem...... cells are not subject to these issues. This review will therefore focus on adult stem cells. Based on their extensive differentiation potential and, in some cases, the relative ease of their isolation, adult stem cells are appropriate for clinical development. Recently, several observations suggest...

Two subpopulations of stem cells for T cell lineage

International Nuclear Information System (INIS)

Katsura, Y.; Amagai, T.; Kina, T.; Sado, T.; Nishikawa, S.

1985-01-01

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

Nanomaterials for Engineering Stem Cell Responses.

Science.gov (United States)

Kerativitayanan, Punyavee; Carrow, James K; Gaharwar, Akhilesh K

2015-08-05

Recent progress in nanotechnology has stimulated the development of multifunctional biomaterials for tissue engineering applications. Synergistic interactions between nanomaterials and stem cell engineering offer numerous possibilities to address some of the daunting challenges in regenerative medicine, such as controlling trigger differentiation, immune reactions, limited supply of stem cells, and engineering complex tissue structures. Specifically, the interactions between stem cells and their microenvironment play key roles in controlling stem cell fate, which underlines therapeutic success. However, the interactions between nanomaterials and stem cells are not well understood, and the effects of the nanomaterials shape, surface morphology, and chemical functionality on cellular processes need critical evaluation. In this Review, focus is put on recent development in nanomaterial-stem cell interactions, with specific emphasis on their application in regenerative medicine. Further, the emerging technologies based on nanomaterials developed over the past decade for stem cell engineering are reviewed, as well as the potential applications of these nanomaterials in tissue regeneration, stem cell isolation, and drug/gene delivery. It is anticipated that the enhanced understanding of nanomaterial-stem cell interactions will facilitate improved biomaterial design for a range of biomedical and biotechnological applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Fountain of Stem Cell-Based Youth? Online Portrayals of Anti-Aging Stem Cell Technologies.

Science.gov (United States)

Rachul, Christen M; Percec, Ivona; Caulfield, Timothy

2015-08-01

The hype surrounding stem cell science has created a market opportunity for the cosmetic industry. Cosmetic and anti-aging products and treatments that make claims regarding stem cell technology are increasingly popular, despite a lack of evidence for safety and efficacy of such products. This study explores how stem cell-based products and services are portrayed to the public through online sources, in order to gain insight into the key messages available to consumers. A content analysis of 100 web pages was conducted to examine the portrayals of stem cell-based cosmetic and anti-aging products and treatments. A qualitative discourse analysis of one web page further examined how language contributes to the portrayals of these products and treatments to public audiences. The majority of web pages portrayed stem cell-based products as ready for public use. Very few web pages substantiated claims with scientific evidence, and even fewer mentioned any risks or limitations associated with stem cell science. The discourse analysis revealed that the framing and use of metaphor obscures the certainty of the efficacy of and length of time for stem cell-based anti-aging technology to be publicly available. This study highlights the need to educate patients and the public on the current limits of stem cell applications in this context. In addition, generating scientific evidence for stem cell-based anti-aging and aesthetic applications is needed for optimizing benefits and minimizing adverse effects for the public. Having more evidence on efficacy and risks will help to protect patients who are eagerly seeking out these treatments. © 2015 The American Society for Aesthetic Plastic Surgery, Inc. Reprints and permission: journals.permissions@oup.com.

Dental pulp stem cells in regenerative dentistry.

Science.gov (United States)

Casagrande, Luciano; Cordeiro, Mabel M; Nör, Silvia A; Nör, Jacques E

2011-01-01

Stem cells constitute the source of differentiated cells for the generation of tissues during development, and for regeneration of tissues that are diseased or injured postnatally. In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that span from Alzheimer's disease to cardiac ischemia to bone or tooth loss. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental pulp is considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that dental pulp stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. The dental pulp stem cells are highly proliferative. This characteristic facilitates ex vivo expansion and enhances the translational potential of these cells. Notably, the dental pulp is arguably the most accessible source of postnatal stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental pulp an attractive source of mesenchymal stem cells for tissue regeneration. This review discusses fundamental concepts of stem cell biology and tissue engineering within the context of regenerative dentistry.

Human iPS Cell-Derived Germ Cells: Current Status and Clinical Potential

Directory of Open Access Journals (Sweden)

Tetsuya Ishii

2014-10-01

Full Text Available Recently, fertile spermatozoa and oocytes were generated from mouse induced pluripotent (iPS cells using a combined in vitro and in vivo induction system. With regard to germ cell induction from human iPS cells, progress has been made particularly in the male germline, demonstrating in vitro generation of haploid, round spermatids. Although iPS-derived germ cells are expected to be developed to yield a form of assisted reproductive technology (ART that can address unmet reproductive needs, genetic and/or epigenetic instabilities abound in iPS cell generation and germ cell induction. In addition, there is still room to improve the induction protocol in the female germline. However, rapid advances in stem cell research are likely to make such obstacles surmountable, potentially translating induced germ cells into the clinical setting in the immediate future. This review examines the current status of the induction of germ cells from human iPS cells and discusses the clinical potential, as well as future directions.

Deriving multipotent stem cells from mouse spermatogonial stem cells: a new tool for developmental and clinical research

NARCIS (Netherlands)

de Rooij, Dirk G.; Mizrak, S. Canan

2008-01-01

In recent years, embryonic stem (ES) cell-like cells have been obtained from cultured mouse spermatogonial stem cells (SSCs). These advances have shown that SSCs can transition from being the stem cell-producing cells of spermatogenesis to being multipotent cells that can differentiate into

Stem cells in bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Seong, Jeong Min [Department of Preventive and Social Dentistry and Institute of Oral Biology, College of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Byung-Chul; Park, Jae-Hong; Kwon, Il Keun; Hwang, Yu-Shik [Department of Maxillofacial Biomedical Engineering and Institute of Oral Biology, College of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Mantalaris, Anathathios, E-mail: yshwang@khu.ac.k [Department of Chemical Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)

2010-12-15

Bone tissue engineering has been one of the most promising areas of research, providing a potential clinical application to cure bone defects. Recently, various stem cells including embryonic stem cells (ESCs), bone marrow-derived mesenchymal stem cells (BM-MSCs), umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), adipose tissue-derived stem cells (ADSCs), muscle-derived stem cells (MDSCs) and dental pulp stem cells (DPSCs) have received extensive attention in the field of bone tissue engineering due to their distinct biological capability to differentiate into osteogenic lineages. The application of these stem cells to bone tissue engineering requires inducing in vitro differentiation of these cells into bone forming cells, osteoblasts. For this purpose, efficient in vitro differentiation towards osteogenic lineage requires the development of well-defined and proficient protocols. This would reduce the likelihood of spontaneous differentiation into divergent lineages and increase the available cell source for application to bone tissue engineering therapies. This review provides a critical examination of the various experimental strategies that could be used to direct the differentiation of ESC, BM-MSC, UCB-MSC, ADSC, MDSC and DPSC towards osteogenic lineages and their potential applications in tissue engineering, particularly in the regeneration of bone. (topical review)

Stem cells in bone tissue engineering

International Nuclear Information System (INIS)

Seong, Jeong Min; Kim, Byung-Chul; Park, Jae-Hong; Kwon, Il Keun; Hwang, Yu-Shik; Mantalaris, Anathathios

2010-01-01

Bone tissue engineering has been one of the most promising areas of research, providing a potential clinical application to cure bone defects. Recently, various stem cells including embryonic stem cells (ESCs), bone marrow-derived mesenchymal stem cells (BM-MSCs), umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), adipose tissue-derived stem cells (ADSCs), muscle-derived stem cells (MDSCs) and dental pulp stem cells (DPSCs) have received extensive attention in the field of bone tissue engineering due to their distinct biological capability to differentiate into osteogenic lineages. The application of these stem cells to bone tissue engineering requires inducing in vitro differentiation of these cells into bone forming cells, osteoblasts. For this purpose, efficient in vitro differentiation towards osteogenic lineage requires the development of well-defined and proficient protocols. This would reduce the likelihood of spontaneous differentiation into divergent lineages and increase the available cell source for application to bone tissue engineering therapies. This review provides a critical examination of the various experimental strategies that could be used to direct the differentiation of ESC, BM-MSC, UCB-MSC, ADSC, MDSC and DPSC towards osteogenic lineages and their potential applications in tissue engineering, particularly in the regeneration of bone. (topical review)

Potential feasibility of dental stem cells for regenerative therapies: stem cell transplantation and whole-tooth engineering.

Science.gov (United States)

Nakahara, Taka

2011-07-01

Multipotent mesenchymal stem cells from bone marrow are expected to be a somatic stem cell source for the development of new cell-based therapy in regenerative medicine. However, dental clinicians are unlikely to carry out autologous cell/tissue collection from patients (i.e., marrow aspiration) as a routine procedure in their clinics; hence, the utilization of bone marrow stem cells seems impractical in the dental field. Dental tissues harvested from extracted human teeth are well known to contain highly proliferative and multipotent stem cell compartments and are considered to be an alternative autologous cell source in cell-based medicine. This article provides a short overview of the ongoing studies for the potential application of dental stem cells and suggests the utilization of 2 concepts in future regenerative medicine: (1) dental stem cell-based therapy for hepatic and other systemic diseases and (2) tooth replacement therapy using the bioengineered human whole tooth, called the "test-tube dental implant." Regenerative therapies will bring new insights and benefits to the fields of clinical medicine and dentistry.

Cell surface fucosylation does not affect development of colon tumors in mice with germline Smad3 mutation

Science.gov (United States)

Domino, Steven E.; Karnak, David M.; Hurd, Elizabeth A.

2006-01-01

Background/Aims: Neoplasia-related alterations in cell surface α(1,2)fucosylated glycans have been reported in multiple tumors including colon, pancreas, endometrium, cervix, bladder, lung, and choriocarcinoma. Spontaneous colorectal tumors from mice with a germline null mutation of transforming growth factor-β signaling gene Smad3 (Madh3) were tested for α(1,2)fucosylated glycan expression. Methods: Ulex Europaeus Agglutinin-I lectin staining, fucosyltransferase gene northern blot analysis, and a cross of mutant mice with Fut2 and Smad3 germline mutations were performed. Results: Spontaneous colorectal tumors from Smad3 (-/-) homozygous null mice were found to express α(1,2)fucosylated glycans in an abnormal pattern compared to adjacent nonneoplastic colon. Northern blot analysis of α(1,2)fucosyltransferase genes Fut1 and Fut2 revealed that Fut2, but not Fut1, steady-state mRNA levels were significantly increased in tumors relative to adjacent normal colonic mucosa. Mutant mice with a Fut2-inactivating germline mutation were crossed with Smad3 targeted mice. In Smad3 (-/-)/Fut2 (-/-) double knock-out mice, UEA-I lectin staining was eliminated from colon and colon tumors, however, the number and size of tumors present by 24 weeks of age did not vary regardless of the Fut2 genotype. Conclusions: In this model of colorectal cancer, cell surface α(1,2)fucosylation does not affect development of colon tumors. PMID:17264540

Clinical trials for stem cell therapies

Directory of Open Access Journals (Sweden)

Lomax Geoff

2011-05-01

Full Text Available Abstract In recent years, clinical trials with stem cells have taken the emerging field in many new directions. While numerous teams continue to refine and expand the role of bone marrow and cord blood stem cells for their vanguard uses in blood and immune disorders, many others are looking to expand the uses of the various types of stem cells found in bone marrow and cord blood, in particular mesenchymal stem cells, to uses beyond those that could be corrected by replacing cells in their own lineage. Early results from these trials have produced mixed results often showing minor or transitory improvements that may be attributed to extracellular factors. More research teams are accelerating the use of other types of adult stem cells, in particular neural stem cells for diseases where beneficial outcome could result from either in-lineage cell replacement or extracellular factors. At the same time, the first three trials using cells derived from pluripotent cells have begun.

Effect of Gsk3 inhibitor CHIR99021 on aneuploidy levels in rat embryonic stem cells.

Science.gov (United States)

Bock, Anagha S; Leigh, Nathan D; Bryda, Elizabeth C

2014-06-01

Germline competent embryonic stem (ES) cells can serve as a tool to create genetically engineered rat strains used to elucidate gene function or provide disease models. In optimum culture conditions, ES cells are able to retain their pluripotent state. The type of components present and their concentration in ES cell culture media greatly influences characteristics of ES cells including the ability to maintain the cells in a pluripotent state. We routinely use 2i media containing inhibitors CHIR99021 and PD0325901 to culture rat ES cells. CHIR99021 specifically inhibits the Gsk3β pathway. We have found that the vendor source of CHIR99021 has a measurable influence on the level of aneuploidy seen over time as rat ES cells are passaged. Karyotyping of three different rat ES cell lines passaged multiple times showed increased aneuploidy when CHIR99021 from source B was used. Mass spectrometry analysis of this inhibitor showed the presence of unexpected synthetic small molecules, which might directly or indirectly cause increases in chromosome instability. Identifying these molecules could further understanding of their influence on chromosome stability and indicate how to improve synthesis of this media component to prevent deleterious effects in culture.

Redox regulation of plant stem cell fate.

Science.gov (United States)

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

2017-10-02

Despite the importance of stem cells in plant and animal development, the common mechanisms of stem cell maintenance in both systems have remained elusive. Recently, the importance of hydrogen peroxide (H 2 O 2 ) signaling in priming stem cell differentiation has been extensively studied in animals. Here, we show that different forms of reactive oxygen species (ROS) have antagonistic roles in plant stem cell regulation, which were established by distinct spatiotemporal patterns of ROS-metabolizing enzymes. The superoxide anion (O2·-) is markedly enriched in stem cells to activate WUSCHEL and maintain stemness, whereas H 2 O 2 is more abundant in the differentiating peripheral zone to promote stem cell differentiation. Moreover, H 2 O 2 negatively regulates O2·- biosynthesis in stem cells, and increasing H 2 O 2 levels or scavenging O2·- leads to the termination of stem cells. Our results provide a mechanistic framework for ROS-mediated control of plant stem cell fate and demonstrate that the balance between O2·- and H 2 O 2 is key to stem cell maintenance and differentiation. © 2017 The Authors.

Ovarian Stem Cells–-the Pros and Cons

Directory of Open Access Journals (Sweden)

Ayelet Evron

2013-01-01

Full Text Available The potential for postnatal de novo oogenesis in mammals and in humans has become very controversial in the fields of reproductive science and biology. Historically, it has been thought that females of most mammalian species lose the ability to produce oocytes at birth. A contemporary understanding of stem cell biology together with novel experimental methods has challenged the model of a prenatal fixed ovarian primordial follicle pool that declines with age. Researchers have suggested replenishment of post-natal oocytes by germ-line stem cells (GSCs. According to this theory, GSCs produce oocytes and primordial follicles throughout the lifetime of the adult female. This review describes recent approaches supporting the revolutionary idea of de novo oogenesis in mammals and humans of reproductive-age and provides counter arguments from opponents of this novel and innovative concept.

Methods for Stem Cell Production and Therapy

Science.gov (United States)

Valluri, Jagan V. (Inventor); Claudio, Pier Paolo (Inventor)

2015-01-01

The present invention relates to methods for rapidly expanding a stem cell population with or without culture supplements in simulated microgravity conditions. The present invention relates to methods for rapidly increasing the life span of stem cell populations without culture supplements in simulated microgravity conditions. The present invention also relates to methods for increasing the sensitivity of cancer stem cells to chemotherapeutic agents by culturing the cancer stem cells under microgravity conditions and in the presence of omega-3 fatty acids. The methods of the present invention can also be used to proliferate cancer cells by culturing them in the presence of omega-3 fatty acids. The present invention also relates to methods for testing the sensitivity of cancer cells and cancer stem cells to chemotherapeutic agents by culturing the cancer cells and cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce tissue for use in transplantation by culturing stem cells or cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce cellular factors and growth factors by culturing stem cells or cancer stem cells under microgravity conditions. The methods of the present invention can also be used to produce cellular factors and growth factors to promote differentiation of cancer stem cells under microgravity conditions.

Stem cell biology meets systems biology

OpenAIRE

Roeder, I.; Radtke, F.

2009-01-01

Stem cells and their descendents are the building blocks of life. How stem cell populations guarantee their maintenance and/or self-renewal, and how individual stem cells decide to transit from one cell stage to another to generate different cell types are long-standing and fascinating questions in the field. Here, we review the discussions that took place at a recent EMBO conference in Cambridge, UK, in which these questions were placed in the context of the latest advances in stem cell biol...

Mesenchymal stem cells: cell biology and potential use in therapy

DEFF Research Database (Denmark)

Kassem, Moustapha; Kristiansen, Malthe; Abdallah, Basem M

2004-01-01

Mesenchymal stem cells are clonogenic, non-haematopoietic stem cells present in the bone marrow and are able to differentiate into multiple mesoderm-type cell lineages e.g. osteoblasts, chondrocytes, endothelial-cells and also non-mesoderm-type lineages e.g. neuronal-like cells. Several methods...... are currently available for isolation of the mesenchymal stem cells based on their physical and immunological characteristics. Because of the ease of their isolation and their extensive differentiation potential, mesenchymal stem cells are among the first stem cell types to be introduced in the clinic. Recent...... studies have demonstrated that the life span of mesenchymal stem cells in vitro can be extended by increasing the levels of telomerase expression in the cells and thus allowing culture of large number of cells needed for therapy. In addition, it has been shown that it is possible to culture the cells...

Cell Cycle Regulation of Stem Cells by MicroRNAs.

Science.gov (United States)

Mens, Michelle M J; Ghanbari, Mohsen

2018-06-01

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules involved in the regulation of gene expression. They are involved in the fine-tuning of fundamental biological processes such as proliferation, differentiation, survival and apoptosis in many cell types. Emerging evidence suggests that miRNAs regulate critical pathways involved in stem cell function. Several miRNAs have been suggested to target transcripts that directly or indirectly coordinate the cell cycle progression of stem cells. Moreover, previous studies have shown that altered expression levels of miRNAs can contribute to pathological conditions, such as cancer, due to the loss of cell cycle regulation. However, the precise mechanism underlying miRNA-mediated regulation of cell cycle in stem cells is still incompletely understood. In this review, we discuss current knowledge of miRNAs regulatory role in cell cycle progression of stem cells. We describe how specific miRNAs may control cell cycle associated molecules and checkpoints in embryonic, somatic and cancer stem cells. We further outline how these miRNAs could be regulated to influence cell cycle progression in stem cells as a potential clinical application.

Extinction models for cancer stem cell therapy

Science.gov (United States)

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

Stem cell therapy. Use of differentiated pluripotent stem cells as replacement therapy for treating disease

DEFF Research Database (Denmark)

Fox, Ira J; Daley, George Q; Goldman, Steven A

2014-01-01

Pluripotent stem cells (PSCs) directed to various cell fates holds promise as source material for treating numerous disorders. The availability of precisely differentiated PSC-derived cells will dramatically affect blood component and hematopoietic stem cell therapies and should facilitate......, and industry is critical for generating new stem cell-based therapies....... treatment of diabetes, some forms of liver disease and neurologic disorders, retinal diseases, and possibly heart disease. Although an unlimited supply of specific cell types is needed, other barriers must be overcome. This review of the state of cell therapies highlights important challenges. Successful...

Primordial dwarfism gene maintains Lin28 expression to safeguard embryonic stem cells from premature differentiation.

Science.gov (United States)

Dai, Qian; Luan, Guangxin; Deng, Li; Lei, Tingjun; Kang, Han; Song, Xu; Zhang, Yujun; Xiao, Zhi-Xiong; Li, Qintong

2014-05-08

Primordial dwarfism (PD) is characterized by global growth failure, both during embryogenesis and postnatally. Loss-of-function germline mutations in La ribonucleoprotein domain family, member 7 (LAPR7) have recently been linked to PD. Paradoxically, LARP7 deficiency was previously assumed to be associated with increased cell growth and proliferation via activation of positive transcription elongation factor b (P-TEFb). Here, we show that Larp7 deficiency likely does not significantly increase P-TEFb activity. We further discover that Larp7 knockdown does not affect pluripotency but instead primes embryonic stem cells (ESCs) for differentiation via downregulation of Lin28, a positive regulator of organismal growth. Mechanistically, we show that Larp7 interacts with a poly(A) polymerase Star-PAP to maintain Lin28 mRNA stability. We propose that proper regulation of Lin28 and PTEFb is essential for embryonic cells to achieve a sufficient number of cell divisions prior to differentiation and ultimately to maintain proper organismal size. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Stem Cell Transplantation from Bench to Bedside

Indian Academy of Sciences (India)

Table of contents. Stem Cell Transplantation from Bench to Bedside · Slide 2 · Slide 3 · Slide 4 · Principles of an allogeneic stem cell transplant · Principle of an allogeneic stem cell transplant · Principle of an autologous Stem Cell Transplant · Slide 8 · Conditioning · Slide 10 · Slide 11 · Stem Cell Transplantation · Slide 13.

Human stromal (mesenchymal) stem cells

DEFF Research Database (Denmark)

Aldahmash, Abdullah; Zaher, Walid; Al-Nbaheen, May

2012-01-01

Human stromal (mesenchymal) stem cells (hMSC) represent a group of non-hematopoietic stem cells present in the bone marrow stroma and the stroma of other organs including subcutaneous adipose tissue, placenta, and muscles. They exhibit the characteristics of somatic stem cells of self......-renewal and multi-lineage differentiation into mesoderm-type of cells, e.g., to osteoblasts, adipocytes, chondrocytes and possibly other cell types including hepatocytes and astrocytes. Due to their ease of culture and multipotentiality, hMSC are increasingly employed as a source for cells suitable for a number...

Stem cells for tooth engineering

Directory of Open Access Journals (Sweden)

G Bluteau

2008-07-01

Full Text Available Tooth development results from sequential and reciprocal interactions between the oral epithelium and the underlying neural crest-derived mesenchyme. The generation of dental structures and/or entire teeth in the laboratory depends upon the manipulation of stem cells and requires a synergy of all cellular and molecular events that finally lead to the formation of tooth-specific hard tissues, dentin and enamel. Although mesenchymal stem cells from different origins have been extensively studied in their capacity to form dentin in vitro, information is not yet available concerning the use of epithelial stem cells. The odontogenic potential resides in the oral epithelium and thus epithelial stem cells are necessary for both the initiation of tooth formation and enamel matrix production. This review focuses on the different sources of stem cells that have been used for making teeth in vitro and their relative efficiency. Embryonic, post-natal or even adult stem cells were assessed and proved to possess an enormous regenerative potential, but their application in dental practice is still problematic and limited due to various parameters that are not yet under control such as the high risk of rejection, cell behaviour, long tooth eruption period, appropriate crown morphology and suitable colour. Nevertheless, the development of biological approaches for dental reconstruction using stem cells is promising and remains one of the greatest challenges in the dental field for the years to come.

Placenta-an alternative source of stem cells

International Nuclear Information System (INIS)

Matikainen, Tiina; Laine, Jarmo

2005-01-01

The two most promising practical applications of human stem cells are cellular replacement therapies in human disease and toxicological screening of candidate drug molecules. Both require a source of human stem cells that can be isolated, purified, expanded in number and differentiated into the cell type of choice in a controlled manner. Currently, uses of both embryonic and adult stem cells are investigated. While embryonic stem cells are pluripotent and can differentiate into any specialised cell type, their use requires establishment of embryonic stem cell lines using the inner cell mass of an early pre-implantation embryo. As the blastocyst is destroyed during the process, ethical issues need to be carefully considered. The use of embryonic stem cells is also limited by the difficulties in growing large numbers of the cells without inducing spontaneous differentiation, and the problems in controlling directed differentiation of the cells. The use of adult stem cells, typically derived from bone marrow, but also from other tissues, is ethically non-controversial but their differentiation potential is more limited than that of the embryonic stem cells. Since human cord blood, umbilical cord, placenta and amnion are normally discarded at birth, they provide an easily accessible alternative source of stem cells. We review the potential and current status of the use of adult stem cells derived from the placenta or umbilical cord in therapeutic and toxicological applications

Biomechanics of stem cells

Science.gov (United States)

Spector, A. A.; Yuan, D.; Somers, S.; Grayson, W. L.

2018-04-01

Stem cells play a key role in the healthy development and maintenance of organisms. They are also critically important in medical treatments of various diseases. It has been recently demonstrated that the mechanical factors such as forces, adhesion, stiffness, relaxation, etc. have significant effects on stem cell functions. Under physiological conditions, cells (stem cells) in muscles, heart, and blood vessels are under the action of externally applied strains. We consider the stem cell microenvironment and performance associated with their conversion (differentiation) into skeletal muscle cells. Two problems are studied by using mathematical models whose parameters are then optimized by fitting experiments. First, we present our analysis of the process of stem cell differentiation under the application of cyclic unidirectional strain. This process is interpreted as a transition through several (six) stages where each of them is defined in terms of expression of a set of factors typical to skeletal muscle cells. The stem cell evolution toward muscle cells is described by a system of nonlinear ODEs. The parameters of the model are determined by fitting the experimental data on the time course of expression of the factors under consideration. Second, we analyse the mechanical (relaxation) properties of a scaffold that serves as the microenvironment for stem cells differentiation into skeletal muscle cells. This scaffold (surrounded by a liquid solution) is composed of unidirectional fibers with pores between them. The relaxation properties of the scaffold are studied in an experiment where a long cylindrical specimen is loaded by the application of ramp displacement until the strain reaches a prescribed value. The magnitude of the corresponding load is recorded. The specimen is considered as transversely isotropic poroelastic cylinder whose force relaxation is associated with liquid diffusion through the pores. An analytical solution for the total force applied to

Amniotic fluid stem cells prevent follicle atresia and rescue fertility of mice with premature ovarian failure induced by chemotherapy.

Science.gov (United States)

Xiao, Guan-Yu; Liu, I-Hsuan; Cheng, Chun-Chun; Chang, Chia-Chun; Lee, Yen-Hua; Cheng, Winston Teng-Kuei; Wu, Shinn-Chih

2014-01-01

Chemotherapy used to treat cancer may cause irreversible premature ovarian failure (POF). Of late, amniotic fluid stem cells (AFSCs) provide a novel source for regenerative medicine because of their primitive stage, low immunogenicity, and easy accessibility. In this study, we isolated AFSCs from transgenic mice that ubiquitously express enhanced green fluorescence protein (EGFP). These AFSCs exhibited morphologies, immunophenotypes, and mesoderm trilineage differentiation potentials similar to mesenchymal stem cells (MSCs). Further, AFSCs proliferated faster than MSCs and expressed OCT4, a marker for pluripotency. To investigate their potential in recovering fertility in POF model, AFSCs were transplanted into the ovaries of mice with POF six weeks post induction using chemotherapeutic drugs, busulfan and cyclophosphamide. AFSCs could rescue the reproductive ability of mice with POF by preventing follicle atresia and sustaining the healthy follicles. Notably, the transplanted AFSCs did not differentiate into granulosa and germline cells in vivo. After one month, the decreased numbers of transplanted AFSCs accompanied with the reduced beneficial effects indicated that the therapeutic efficacy were directly from AFSCs. These findings demonstrated the therapeutic effects of AFSCs and suggested the promise of AFSCs for treating infertility and POF caused by chemotherapy.

Amniotic fluid stem cells prevent follicle atresia and rescue fertility of mice with premature ovarian failure induced by chemotherapy.

Directory of Open Access Journals (Sweden)

Guan-Yu Xiao

Full Text Available Chemotherapy used to treat cancer may cause irreversible premature ovarian failure (POF. Of late, amniotic fluid stem cells (AFSCs provide a novel source for regenerative medicine because of their primitive stage, low immunogenicity, and easy accessibility. In this study, we isolated AFSCs from transgenic mice that ubiquitously express enhanced green fluorescence protein (EGFP. These AFSCs exhibited morphologies, immunophenotypes, and mesoderm trilineage differentiation potentials similar to mesenchymal stem cells (MSCs. Further, AFSCs proliferated faster than MSCs and expressed OCT4, a marker for pluripotency. To investigate their potential in recovering fertility in POF model, AFSCs were transplanted into the ovaries of mice with POF six weeks post induction using chemotherapeutic drugs, busulfan and cyclophosphamide. AFSCs could rescue the reproductive ability of mice with POF by preventing follicle atresia and sustaining the healthy follicles. Notably, the transplanted AFSCs did not differentiate into granulosa and germline cells in vivo. After one month, the decreased numbers of transplanted AFSCs accompanied with the reduced beneficial effects indicated that the therapeutic efficacy were directly from AFSCs. These findings demonstrated the therapeutic effects of AFSCs and suggested the promise of AFSCs for treating infertility and POF caused by chemotherapy.

Comparison of Gene Expression in Human Embryonic Stem Cells, hESC-Derived Mesenchymal Stem Cells and Human Mesenchymal Stem Cells

OpenAIRE

Romain Barbet; Isabelle Peiffer; Antoinette Hatzfeld; Pierre Charbord; Jacques A. Hatzfeld

2011-01-01

We present a strategy to identify developmental/differentiation and plasma membrane marker genes of the most primitive human Mesenchymal Stem Cells (hMSCs). Using sensitive and quantitative TaqMan Low Density Arrays (TLDA) methodology, we compared the expression of 381 genes in human Embryonic Stem Cells (hESCs), hESC-derived MSCs ...

Differentiation of embryonic stem cells towards hematopoietic cells: progress and pitfalls.

Science.gov (United States)

Tian, Xinghui; Kaufman, Dan S

2008-07-01

Hematopoietic development from embryonic stem cells has been one of the most productive areas of stem cell biology. Recent studies have progressed from work with mouse to human embryonic stem cells. Strategies to produce defined blood cell populations can be used to better understand normal and abnormal hematopoiesis, as well as potentially improve the generation of hematopoietic cells with therapeutic potential. Molecular profiling, phenotypic and functional analyses have all been utilized to demonstrate that hematopoietic cells derived from embryonic stem cells most closely represent a stage of hematopoiesis that occurs at embryonic/fetal developmental stages. Generation of hematopoietic stem/progenitor cells comparable to hematopoietic stem cells found in the adult sources, such as bone marrow and cord blood, still remains challenging. However, genetic manipulation of intrinsic factors during hematopoietic differentiation has proven a suitable approach to induce adult definitive hematopoiesis from embryonic stem cells. Concrete evidence has shown that embryonic stem cells provide a powerful approach to study the early stage of hematopoiesis. Multiple hematopoietic lineages can be generated from embryonic stem cells, although most of the evidence suggests that hematopoietic development from embryonic stem cells mimics an embryonic/fetal stage of hematopoiesis.

In vitro differentiation of primordial germ cells and oocyte-like cells from stem cells.

Science.gov (United States)

Costa, José J N; Souza, Glaucinete B; Soares, Maria A A; Ribeiro, Regislane P; van den Hurk, Robert; Silva, José R V

2018-02-01

Infertility is the result of failure due to an organic disorder of the reproductive organs, especially their gametes. Recently, much progress has been made on generating germ cells, including oocytes, from various types of stem cells. This review focuses on advances in female germ cell differentiation from different kinds of stem cells, with emphasis on embryonic stem cells, adult stem cells, and induced pluripotent stem cells. The advantages and disadvantages of the derivation of female germ cells from several types of stem cells are also highlighted, as well as the ability of stem cells to generate mature and functional female gametes. This review shows that stem cell therapies have opened new frontiers in medicine, especially in the reproductive area, with the possibility of regenerating fertility.

Breast cancer stem cell-like cells are more sensitive to ionizing radiation than non-stem cells: role of ATM.

Directory of Open Access Journals (Sweden)

Seog-Young Kim

Full Text Available There are contradictory observations about the different radiosensitivities of cancer stem cells and cancer non-stem cells. To resolve these contradictory observations, we studied radiosensitivities by employing breast cancer stem cell (CSC-like MDA-MB231 and MDA-MB453 cells as well as their corresponding non-stem cells. CSC-like cells proliferate without differentiating and have characteristics of tumor-initiating cells [1]. These cells were exposed to γ-rays (1.25-8.75 Gy and survival curves were determined by colony formation. A final slope, D(0, of the survival curve for each cell line was determined to measure radiosensitivity. The D(0 of CSC-like and non-stem MDA-MB-453 cells were 1.16 Gy and 1.55 Gy, respectively. Similar results were observed in MDA-MB-231 cells (0.94 Gy vs. 1.56 Gy. After determination of radiosensitivity, we investigated intrinsic cellular determinants which influence radiosensitivity including cell cycle distribution, free-radical scavengers and DNA repair. We observed that even though cell cycle status and antioxidant content may contribute to differential radiosensitivity, differential DNA repair capacity may be a greater determinant of radiosensitivity. Unlike non-stem cells, CSC-like cells have little/no sublethal damage repair, a low intracellular level of ataxia telangiectasia mutated (ATM and delay of γ-H2AX foci removal (DNA strand break repair. These results suggest that low DNA repair capacity is responsible for the high radiosensitivity of these CSC-like cells.

Cancer stem cells, cancer cell plasticity and radiation therapy.

Science.gov (United States)

Vlashi, Erina; Pajonk, Frank

2015-04-01

Since the first prospective identification of cancer stem cells in solid cancers the cancer stem cell hypothesis has reemerged as a research topic of increasing interest. It postulates that solid cancers are organized hierarchically with a small number of cancer stem cells driving tumor growth, repopulation after injury and metastasis. They give rise to differentiated progeny, which lack these features. The model predicts that for any therapy to provide cure, all cancer stem cells have to be eliminated while the survival of differentiated progeny is less critical. In this review we discuss recent reports challenging the idea of a unidirectional differentiation of cancer cells. These reports provide evidence supporting the idea that non-stem cancer cells exhibit a remarkable degree of plasticity that allows them to re-acquire cancer stem cell traits, especially in the context of radiation therapy. We summarize conditions under which differentiation is reversed and discuss the current knowledge of the underlying mechanisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

Legislation governing pluripotent stem cells in South Africa

Directory of Open Access Journals (Sweden)

Michael Pepper

2015-09-01

Full Text Available One of the most exciting areas of medical research involves the use of stem cells for the treatment of patients with a variety of diseases and for tissue repair. Although stem cell research is accelerating rapidly in many countries, it has in the past been limited in South Africa (SA; very little has been done in this country to explore the great potential offered by stem cells to address the high disease burden. Stem cell therapy has however been practised for many years, in SA and worldwide, in the form of haematopoietic stem cell transplantation, mainly for haematological malignancies. From a therapeutic perspective, two types of stem cells can be defined: pluripotent stem cells and adult stem cells. Pluripotent cells derived from the inner cell mass of blastocysts (either from in vitro fertilisation or following somatic cell nuclear transfer are called embryonic stem (ES cells, while those derived by reprogramming adult cells are called induced pluripotent stem (iPS cells. Adult stem cells include haematopoietic, mesenchymal and neural stem cells.The purpose of this article is to critically examine the SA legislation with regard to elements that impact on pluripotent stem cell research and the use of pluripotent stem cells for therapeutic purposes. This includes (but is not limited to legislation from the National Health Act (Chapter 8 in particular and its regulations, and deals with matters related to research on embryos in the stem cell context, somatic cell nuclear transfer, reproductive and therapeutic cloning and the generation and therapeutic use of iPS and ES cells.

In vivo differentiation of induced pluripotent stem cells into neural stem cells by chimera formation.

Science.gov (United States)

Choi, Hyun Woo; Hong, Yean Ju; Kim, Jong Soo; Song, Hyuk; Cho, Ssang Gu; Bae, Hojae; Kim, Changsung; Byun, Sung June; Do, Jeong Tae

2017-01-01

Like embryonic stem cells, induced pluripotent stem cells (iPSCs) can differentiate into all three germ layers in an in vitro system. Here, we developed a new technology for obtaining neural stem cells (NSCs) from iPSCs through chimera formation, in an in vivo environment. iPSCs contributed to the neural lineage in the chimera, which could be efficiently purified and directly cultured as NSCs in vitro. The iPSC-derived, in vivo-differentiated NSCs expressed NSC markers, and their gene-expression pattern more closely resembled that of fetal brain-derived NSCs than in vitro-differentiated NSCs. This system could be applied for differentiating pluripotent stem cells into specialized cell types whose differentiation protocols are not well established.

Experiment list: SRX471838 [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available : ChIPseq GS WT Bmi1; Mus musculus; ChIP-Seq source_name=Cultured germline stem cells || genotype/variation=...Wild-type || strain=CD1 x C57BL/6 || cell type=Cultured germline stem cells || chip antibody=Mouse anti-Bmi1

Experiment list: SRX471836 [Chip-atlas[Archive

Lifescience Database Archive (English)

Full Text Available 0: ChIPseq GS WT Scml2; Mus musculus; ChIP-Seq source_name=Cultured germline stem cells || genotype/variatio...n=Wild-type || strain=CD1 x C57BL/6 || cell type=Cultured germline stem cells || chip antibody=Rabbit anti-S

Stem cell-based approaches in dentistry

Directory of Open Access Journals (Sweden)

TA Mitsiadis

2011-11-01

Full Text Available Repair of dental pulp and periodontal lesions remains a major clinical challenge. Classical dental treatments require the use of specialised tissue-adapted materials with still questionable efficacy and durability. Stem cell-based therapeutic approaches could offer an attractive alternative in dentistry since they can promise physiologically improved structural and functional outcomes. These therapies necessitate a sufficient number of specific stem cell populations for implantation. Dental mesenchymal stem cells can be easily isolated and are amenable to in vitro expansion while retaining their stemness. In vivo studies realised in small and large animals have evidenced the potential of dental mesenchymal stem cells to promote pulp and periodontal regeneration, but have also underlined new important challenges. The homogeneity of stem cell populations and their quality control, the delivery method, the quality of the regenerated dental tissues and their integration to the host tissue are some of the key challenges. The use of bioactive scaffolds that can elicit effective tissue repair response, through activation and mobilisation of endogenous stem cell populations, constitutes another emerging therapeutic strategy. Finally, the use of stem cells and induced pluripotent cells for the regeneration of entire teeth represents a novel promising alternative to dental implant treatment after tooth loss. In this mini-review, we present the currently applied techniques in restorative dentistry and the various attempts that are made to bridge gaps in knowledge regarding treatment strategies by translating basic stem cell research into the dental practice.

Of Microenvironments and Mammary Stem Cells

Energy Technology Data Exchange (ETDEWEB)

LaBarge, Mark A; Petersen, Ole W; Bissell, Mina J

2007-06-01

In most adult tissues there reside pools of stem and progenitor cells inside specialized microenvironments referred to as niches. The niche protects the stem cells from inappropriate expansion and directs their critical functions. Thus guided, stem cells are able to maintain tissue homeostasis throughout the ebb and flow of metabolic and physical demands encountered over a lifetime. Indeed, a pool of stem cells maintains mammary gland structure throughout development, and responds to the physiological demands associated with pregnancy. This review discusses how stem cells were identified in both human and mouse mammary glands; each requiring different techniques that were determined by differing biological needs and ethical constraints. These studies together create a robust portrait of mammary gland biology and identify the location of the stem cell niche, elucidate a developmental hierarchy, and suggest how the niche might be manipulated for therapeutic benefit.

Germline contamination and leakage in whole genome somatic single nucleotide variant detection.

Science.gov (United States)

Sendorek, Dorota H; Caloian, Cristian; Ellrott, Kyle; Bare, J Christopher; Yamaguchi, Takafumi N; Ewing, Adam D; Houlahan, Kathleen E; Norman, Thea C; Margolin, Adam A; Stuart, Joshua M; Boutros, Paul C

2018-01-31

The clinical sequencing of cancer genomes to personalize therapy is becoming routine across the world. However, concerns over patient re-identification from these data lead to questions about how tightly access should be controlled. It is not thought to be possible to re-identify patients from somatic variant data. However, somatic variant detection pipelines can mistakenly identify germline variants as somatic ones, a process called "germline leakage". The rate of germline leakage across different somatic variant detection pipelines is not well-understood, and it is uncertain whether or not somatic variant calls should be considered re-identifiable. To fill this gap, we quantified germline leakage across 259 sets of whole-genome somatic single nucleotide variant (SNVs) predictions made by 21 teams as part of the ICGC-TCGA DREAM Somatic Mutation Calling Challenge. The median somatic SNV prediction set contained 4325 somatic SNVs and leaked one germline polymorphism. The level of germline leakage was inversely correlated with somatic SNV prediction accuracy and positively correlated with the amount of infiltrating normal cells. The specific germline variants leaked differed by tumour and algorithm. To aid in quantitation and correction of leakage, we created a tool, called GermlineFilter, for use in public-facing somatic SNV databases. The potential for patient re-identification from leaked germline variants in somatic SNV predictions has led to divergent open data access policies, based on different assessments of the risks. Indeed, a single, well-publicized re-identification event could reshape public perceptions of the values of genomic data sharing. We find that modern somatic SNV prediction pipelines have low germline-leakage rates, which can be further reduced, especially for cloud-sharing, using pre-filtering software.

Skeletal (stromal) stem cells

DEFF Research Database (Denmark)

Abdallah, Basem M; Kermani, Abbas Jafari; Zaher, Walid

2015-01-01

Skeletal (marrow stromal) stem cells (BMSCs) are a group of multipotent cells that reside in the bone marrow stroma and can differentiate into osteoblasts, chondrocytes and adipocytes. Studying signaling pathways that regulate BMSC differentiation into osteoblastic cells is a strategy....../preadipocyte factor 1 (Dlk1/Pref-1), the Wnt co-receptor Lrp5 and intracellular kinases. This article is part of a Special Issue entitled: Stem Cells and Bone....

The potential application of stem cell in dentistry

Directory of Open Access Journals (Sweden)

Ketut Suardita

2006-12-01

Full Text Available Stem cells are generally defined as cells that have the capacity to self-renewal and differentiate to specialize cell. There are two kinds of stem cell, embryonic stem cell and adult stem cells. Stem cell therapy has been used to treat diseases including Parkinson’s and Alzheimer’s diseases, spinal cord injury, stroke, burns, heart diseases, diabetes, osteoarthritis, and rheumatoid arthritis. Stem cells were found in dental pulp, periodontal ligament, and alveolar bone marrow. Because of their potential in medical therapy, stem cells were used to regenerate lost or damage teeth and periodontal structures. This article discusses the potential application of stem cells for dental field.

Human skeletal muscle-derived stem cells retain stem cell properties after expansion in myosphere culture

International Nuclear Information System (INIS)

Wei, Yan; Li, Yuan; Chen, Chao; Stoelzel, Katharina; Kaufmann, Andreas M.; Albers, Andreas E.

2011-01-01