scholarly journals Molecular Regulation of Paused Pluripotency in Early Mammalian Embryos and Stem Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Vera A. van der Weijden ◽  
Aydan Bulut-Karslioglu
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Reproductive Success ◽  
Environmental Conditions ◽  
Mammalian Species ◽  
Molecular Regulation ◽  
Embryonic Diapause ◽  
Adverse Conditions ◽  
Mammalian Embryos

The energetically costly mammalian investment in gestation and lactation requires plentiful nutritional sources and thus links the environmental conditions to reproductive success. Flexibility in adjusting developmental timing enhances chances of survival in adverse conditions. Over 130 mammalian species can reversibly pause early embryonic development by switching to a near dormant state that can be sustained for months, a phenomenon called embryonic diapause. Lineage-specific cells are retained during diapause, and they proliferate and differentiate upon activation. Studying diapause thus reveals principles of pluripotency and dormancy and is not only relevant for development, but also for regeneration and cancer. In this review, we focus on the molecular regulation of diapause in early mammalian embryos and relate it to maintenance of potency in stem cells in vitro. Diapause is established and maintained by active rewiring of the embryonic metabolome, epigenome, and gene expression in communication with maternal tissues. Herein, we particularly discuss factors required at distinct stages of diapause to induce, maintain, and terminate dormancy.

scholarly journals Signalling pathways and mechanistic cues highlighted by transcriptomic analysis of primordial, primary, and secondary ovarian follicles in domestic cat

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shauna Kehoe ◽  
Katarina Jewgenow ◽  
Paul R. Johnston ◽  
Susan Mbedi ◽  
Beate C. Braun
Keyword(s):  
Gene Expression ◽  
Transforming Growth Factor ◽  
Ovarian Follicle ◽  
Mammalian Species ◽  
Expression Patterns ◽  
Ovarian Follicles ◽  
Domestic Cat ◽  
Transcriptional Analysis ◽  
Ovarian Folliculogenesis

AbstractIn vitro growth (IVG) of dormant primordial ovarian follicles aims to produce mature competent oocytes for assisted reproduction. Success is dependent on optimal in vitro conditions complemented with an understanding of oocyte and ovarian follicle development in vivo. Complete IVG has not been achieved in any other mammalian species besides mice. Furthermore, ovarian folliculogenesis remains sparsely understood overall. Here, gene expression patterns were characterised by RNA-sequencing in primordial (PrF), primary (PF), and secondary (SF) ovarian follicles from Felis catus (domestic cat) ovaries. Two major transitions were investigated: PrF-PF and PF-SF. Transcriptional analysis revealed a higher proportion in gene expression changes during the PrF-PF transition. Key influencing factors during this transition included the interaction between the extracellular matrix (ECM) and matrix metalloproteinase (MMPs) along with nuclear components such as, histone HIST1H1T (H1.6). Conserved signalling factors and expression patterns previously described during mammalian ovarian folliculogenesis were observed. Species-specific features during domestic cat ovarian folliculogenesis were also found. The signalling pathway terms “PI3K-Akt”, “transforming growth factor-β receptor”, “ErbB”, and “HIF-1” from the functional annotation analysis were studied. Some results highlighted mechanistic cues potentially involved in PrF development in the domestic cat. Overall, this study provides an insight into regulatory factors and pathways during preantral ovarian folliculogenesis in domestic cat.

Production of chimeras by blastocyst and morula injection of targeted ES cells

1999 ◽  
Author(s):  
Virginia Papaioannou ◽  
Randall Johnson
Keyword(s):  
Stem Cells ◽  
Gene Targeting ◽  
Es Cells ◽  
Embryonic Stem ◽  
Embryonic Cells ◽  
Cell Potential ◽  
Teratocarcinoma Cell ◽  
Normal Manner ◽  
Mammalian Embryos

The ability of mammalian embryos to incorporate foreign cells and develop as chimeras has been exploited for a variety of purposes including the elucidation of cell lineages, the investigation of cell potential, the perpetuation of mutations produced in embryonic stem (ES) cells by gene targeting, and the subsequent analysis of these mutations. The extent of contribution of the foreign cells depends on their developmental synchrony with the host embryo and their mitotic and developmental potential, which may be severely restricted if the cells bear mutations. If the goal in making chimeras is the transmission of a mutation produced by gene targeting to the next generation, the mutant ES cells must have the capacity to undergo meiosis and gametogenesis. Cells from two different mammalian embryos were first combined experimentally to produce a composite animal, dubbed a chimera, nearly four decades ago. Pairs of cleaving, pre-implantation embryos were mechanically associated in vitro until they aggregated together to make single large morulae; these in turn resulted in chimeric offspring (1). Genetic markers were used to distinguish the contributions of the two embryos in these animals. Since then, various methods for making chimeras have been explored to address different types of questions (2). In 1972 it was reported that highly asynchronous embryonic cells, which had been cultured in vitro, could contribute to chimeras upon re-introduction into pre-implantation embryos (3). Not long afterward, several groups working with teratocarcinomas, tumours derived from germ cells of the gonad, discovered that stem cells from these tumours, known as embryonal carcinoma cells, could contribute to an embryo if introduced into pre-implantation stages (4-6). It appeared that the undifferentiated stem cells of the tumour had enough features in common with early embryonic cells that they could respond to the embryonic environment, differentiating in a normal manner, even after long periods in vitro. Their embryonic potential was limited, however, and many teratocarcinoma cell lines made only meagre contributions to the developing fetus or even produced tumours in chimeras (7). Either their derivation from tumours or their extended sojourn in vitro rendered these cells so dissimilar from early embryonic cells that they rarely, if ever, had full embryonic potential.

scholarly journals Cell-Free Demineralized Bone Matrix for Mesenchymal Stem Cells Survival and Colonization

Materials ◽  
2019 ◽  
Vol 12 (9) ◽  
pp. 1360 ◽  
Author(s):  
Monica Mattioli-Belmonte ◽  
Francesca Montemurro ◽  
Caterina Licini ◽  
Iolanda Iezzi ◽  
Manuela Dicarlo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Tissue Regeneration ◽  
Demineralized Bone Matrix ◽  
Bone Matrix ◽  
Morphological Observation ◽  
Type I ◽  
Demineralized Bone

Decellularized bone matrix is receiving much attention as biological scaffolds and implantable biomaterials for bone tissue regeneration. Here, we evaluated the efficacy of a cell-free demineralized bone matrix on mesenchymal stem cells (MSCs) survival and differentiation in vitro. The seeding of human umbilical cord-derived MSCs (hUC-SCs) on decellularized bone matrices up to 14 days was exploited, assessing their capability of scaffold colonization and evaluating gene expression of bone markers. Light and Scanning Electron Microscopies were used. The obtained cell-free decalcified structures showed elastic moduli attributable to both topology and biochemical composition. Morphological observation evidenced an almost complete colonization of the scaffolds after 14 days of culture. Moreover, in hUC-SCs cultured on decalcified scaffolds, without the addition of any osteoinductive media, there was an upregulation of Collagen Type I (COL1) and osteonectin (ON) gene expression, especially on day 14. Modifications in the expression of genes engaged in stemness were also detected. In conclusion, the proposed decellularized bone matrix can induce the in vitro hUC-SCs differentiation and has the potential to be tested for in in vivo tissue regeneration.

scholarly journals Tec1p-Independent Activation of a Hypha-Associated Candida albicans Virulence Gene during Infection

2004 ◽  
Vol 72 (4) ◽  
pp. 2386-2389 ◽  
Author(s):  
Peter Staib ◽  
Ayfer Binder ◽  
Marianne Kretschmar ◽  
Thomas Nichterlein ◽  
Klaus Schröppel ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Animal Models ◽  
Environmental Conditions ◽  
Deletion Mutant ◽  
Virulence Gene ◽  
Consensus Sequences ◽  
Site Consensus

ABSTRACT The Tec1p transcription factor is involved in the expression of hypha-specific genes in Candida albicans. Although the induction of the hypha-associated SAP5 gene by serum in vitro depends on Tec1p, deletion of all Tec1p binding site consensus sequences from the SAP5 promoter did not affect its activation. In two different animal models of candidiasis, the SAP5 promoter was induced even in a Δtec1 deletion mutant, demonstrating that the requirement for Tec1p in gene expression in C. albicans depends on the environmental conditions within the host.

scholarly journals Photoperiodic regulation of prolactin secretion: changes in intra-pituitary signalling and lactotroph heterogeneity

2004 ◽  
Vol 180 (3) ◽  
pp. 351-356 ◽  
Author(s):  
JD Johnston
Keyword(s):  
Environmental Conditions ◽  
Seasonal Changes ◽  
Mammalian Species ◽  
Prolactin Secretion ◽  
Day Length ◽  
Pars Tuberalis ◽  
Photoperiodic Regulation ◽  
Pituitary Lactotroph

Many mammalian species utilise day-length (photoperiod) to adapt their physiology to seasonal changes in environmental conditions, via secretion of pineal melatonin. Photoperiodic regulation of prolactin secretion is believed to occur via melatonin-mediated changes in the secretion of a putative prolactin secretagogue, tuberalin, from the pituitary pars tuberalis. Despite the in vivo and in vitro evidence in support of this intra-pituitary signalling mechanism, the identity of tuberalin has yet to be elucidated. This paper reviews recent advances in the characterisation of tuberalin and the regulation of its secretion. Furthermore, the hypothesis that pituitary lactotroph cells display heterogeneity in their response to changing photoperiod and tuberalin secretion is examined.

scholarly journals Icariin promotes cell proliferation and regulates gene expression in human neural stem cells in vitro

2016 ◽  
Vol 14 (2) ◽  
pp. 1316-1322 ◽  
Author(s):  
Pan Yang ◽  
Yun-Qian Guan ◽  
Ya-Li Li ◽  
Li Zhang ◽  
Lan Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Cell Proliferation ◽  
Neural Stem Cells ◽  
Human Neural Stem Cells

scholarly journals Implications and Current Limitations of Oogenesis from Female Germline or Oogonial Stem Cells in Adult Mammalian Ovaries

Cells ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 93 ◽  
Author(s):  
Jessica Martin ◽  
Dori Woods ◽  
Jonathan Tilly
Keyword(s):  
Stem Cells ◽  
Adult Stem Cells ◽  
Ovarian Function ◽  
Mammalian Species ◽  
Large Body ◽  
The Body ◽  
Human Female ◽  
Female Germline

A now large body of evidence supports the existence of mitotically active germ cells in postnatal ovaries of diverse mammalian species, including humans. This opens the possibility that adult stem cells naturally committed to a germline fate could be leveraged for the production of female gametes outside of the body. The functional properties of these cells, referred to as female germline or oogonial stem cells (OSCs), in ovaries of women have recently been tested in various ways, including a very recent investigation of the differentiation capacity of human OSCs at a single cell level. The exciting insights gained from these experiments, coupled with other data derived from intraovarian transplantation and genetic tracing analyses in animal models that have established the capacity of OSCs to generate healthy eggs, embryos and offspring, should drive constructive discussions in this relatively new field to further exploring the value of these cells to the study, and potential management, of human female fertility. Here, we provide a brief history of the discovery and characterization of OSCs in mammals, as well as of the in-vivo significance of postnatal oogenesis to adult ovarian function. We then highlight several key observations made recently on the biology of OSCs, and integrate this information into a broader discussion of the potential value and limitations of these adult stem cells to achieving a greater understanding of human female gametogenesis in vivo and in vitro.

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