scholarly journals Endogenous human stem cell-associated retroviruses

2015 ◽  
Author(s):  
Gennadi Glinsky
Keyword(s):  
Stem Cell ◽  
Malignant Tumors ◽  
Early Stage ◽  
Embryonic Stem ◽  
Preimplantation Embryos ◽  
Human Embryos ◽  
Regulatory Sequences ◽  
Human Stem Cell ◽  
Cancer Phenotypes ◽  
Genome Activation

Recent discoveries of endogenous human stem cell-associated retroviruses (SCARs) revealed consistent activation of specific endogenous retroviral elements in human preimplantation embryos and documented the essential role of the sustained retroviral activities in the maintenance of pluripotency, functional identity and integrity of naïve-state embryonic stem cells, and anti-viral resistance of the early-stage human embryos. SCARs activity have been implicated in seeding thousands’ human-specific regulatory sequences in the hESC genome. Activation of specific SCARs, namely LTR7/HERVH and LTR5_Hs/HERVK, has been demonstrated in patients diagnosed with multiple types of cancer, autoimmune diseases, neurodegenerative disorders and it is likely associated with the emergence of clinically lethal therapy resistant death-from-cancer phenotypes in a sub-set of cancer patients diagnosed with different types of malignant tumors.

scholarly journals Characterization and target genes of nine human PRD-like homeobox domain genes expressed exclusively in early embryos

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Elo Madissoon ◽  
Eeva-Mari Jouhilahti ◽  
Liselotte Vesterlund ◽  
Virpi Töhönen ◽  
Kaarel Krjutškov ◽  
...  
Keyword(s):  
Stem Cells ◽  
Transcription Factors ◽  
Target Genes ◽  
Genomic Sequence ◽  
Embryonic Stem ◽  
Homeobox Genes ◽  
Preimplantation Embryos ◽  
Human Embryos ◽  
Preimplantation Embryo Development ◽  
Genome Activation

Abstract PAIRED (PRD)-like homeobox genes belong to a class of predicted transcription factor genes. Several of these PRD-like homeobox genes have been predicted in silico from genomic sequence but until recently had no evidence of transcript expression. We found recently that nine PRD-like homeobox genes, ARGFX, CPHX1, CPHX2, DPRX, DUXA, DUXB, NOBOX, TPRX1 and TPRX2, were expressed in human preimplantation embryos. In the current study we characterized these PRD-like homeobox genes in depth and studied their functions as transcription factors. We cloned multiple transcript variants from human embryos and showed that the expression of these genes is specific to embryos and pluripotent stem cells. Overexpression of the genes in human embryonic stem cells confirmed their roles as transcription factors as either activators (CPHX1, CPHX2, ARGFX) or repressors (DPRX, DUXA, TPRX2) with distinct targets that could be explained by the amino acid sequence in homeodomain. Some PRD-like homeodomain transcription factors had high concordance of target genes and showed enrichment for both developmentally important gene sets and a 36 bp DNA recognition motif implicated in Embryo Genome Activation (EGA). Our data implicate a role for these previously uncharacterized PRD-like homeodomain proteins in the regulation of human embryo genome activation and preimplantation embryo development.

Dppa2/4 as a trigger of signaling pathways to promote zygote genome activation by binding to CG-rich region

2020 ◽  
Author(s):  
Hanshuang Li ◽  
Chunshen Long ◽  
Jinzhu Xiang ◽  
Pengfei Liang ◽  
Xueling Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Signaling Pathways ◽  
Embryonic Stem ◽  
Proximal Promoter ◽  
Human Embryos ◽  
Double Knockout ◽  
Rich Region ◽  
Induced Pluripotent ◽  
Zygote Genome Activation ◽  
Genome Activation

Abstract Developmental pluripotency-associated 2 (Dppa2) and developmental pluripotency-associated 4 (Dppa4) as positive drivers were helpful for transcriptional regulation of zygotic genome activation (ZGA). Here, we systematically assessed the cooperative interplay of Dppa2 and Dppa4 in regulating cell pluripotency and found that simultaneous overexpression of Dppa2/4 can make induced pluripotent stem cells closer to embryonic stem cells (ESCs). Compared with other pluripotency transcription factors, Dppa2/4 can regulate majorities of signaling pathways by binding on CG-rich region of proximal promoter (0–500 bp), of which 85% and 77% signaling pathways were significantly activated by Dppa2 and Dppa4, respectively. Notably, Dppa2/4 also can dramatically trigger the decisive signaling pathways for facilitating ZGA, including Hippo, MAPK and TGF-beta signaling pathways and so on. At last, we found alkaline phosphatase, placental-like 2 (Alppl2) was completely silenced when Dppa2 and 4 single- or double-knockout in ESC, which is consistent with Dux. Moreover, Alppl2 was significantly activated in mouse 2-cell embryos and 4–8 cells stage of human embryos, further predicted that Alppl2 was directly regulated by Dppa2/4 as a ZGA candidate driver to facilitate pre-embryonic development.

64 RECONSTRUCTION OF HETEROGENEOUS EMBRYOS BY HUMAN SOMATIC CELLS AND BOVINE ENUCLEATED OOCYTES AND ISOLATION OF PUTATIVE HUMAN EMBRYONIC STEM CELL CLONES

2008 ◽  
Vol 20 (1) ◽  
pp. 113
Author(s):  
D. Zhang ◽  
H. M. Zhou
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Skin Fibroblast ◽  
Embryonic Stem ◽  
Human Embryos ◽  
Fibroblast Cells ◽  
Normal Numbers ◽  
Blastocyst Development ◽  
Cell Clones

This study was undertaken to reconstruct heterogeneous nuclear-transferred embryos by using human fetal skin fibroblast cells as nuclear donor cells and the enucleated bovine oocytes as recipient cytoplasts for the purpose of investigating the feasibility of enucleated bovine oocyte cytoplasm as a means of reprogramming human somatic cell nuclei in an attempt to generate an accessible, autologous, and potentially unlimited source of totipotent human embryonic stem cells for transplantation medicine. Bovine ovaries were recovered at a local abattoir and oocytes were in vitro-matured and employed as recipient cytoplasts. A human fibroblast cell line was derived from an aborted fetus at 4 months of age, serum-starved, and used as donor somatic cells. The cultured nuclear transfer embryos were visually assessed for the first completion of cleavage at 48 h of culture, and for subsequent developmental stages at 72 to 168 h. The fusion of fibroblast cells into recipient cytoplasm was induced by electroporation. The fused oocytes were activated by ionomycin with 2 m mL–1 6-DMAP. The activated reconstructed embryos were co-cultured with bovine cumulus cells in synthetic oviduct fluid supplemented with amino acid (SOFaa) and 10% (v/v) fetal calf serum (FCS) for 168 h. Morulae and blastocysts were used for isolating embryonic stem cells. The results indicated that human fetal skin fibroblast cells could maintain normal morphology and characteristics in culture conditions. They proliferated constantly and presented a regular growth curve in culture. Of these cells, 83.3% retained normal numbers of chromosomes after over 20 culture passages. The skin fibroblast cells exhibited normal morphology and retained normal numbers of chromosomes (2n = 64) in serum starvation culture after undergoing freezing and thawing treatment. The first completed cleavage of xenonuclear transplantation human embryos occurred between 24 and 48 h after activation, and morula and blastocyst development was completed between 72 and 168 h. The cleavage rate and the percentage of blastocyst development of the reconstructed embryos were 80.0% and 7.5%, respectively. Putative embryonic stem cell clones were observed, with nest-like morphology, after 3–7 days of culture on a fibroblast cell layer. Identifications by alkaline phosphatase (AKP) showed that the clones presented a positive reaction, which demonstrated that the isolated stem cell clones were embryonic stem cells. This study demonstrated that xenonuclear-transferred human embryos can undergo embryonic division and subsequent development to morula and blastocyst stage, and that human fetal fibroblast nuclei can be reprogrammed in bovine enucleated oocytes. Xenonuclear-transferred human embryos can be an alternative for obtaining human embryonic stem cells.

CAR expression in human embryos and hESC illustrates its role in pluripotency and tight junctions

Reproduction ◽  
2014 ◽  
Vol 148 (5) ◽  
pp. 531-544 ◽  
Author(s):  
M Krivega ◽  
M Geens ◽  
H Van de Velde
Keyword(s):  
Outer Layer ◽  
Transmembrane Domain ◽  
Splice Variants ◽  
Embryonic Stem ◽  
Cell Types ◽  
Preimplantation Development ◽  
Coxsackie Virus ◽  
Preimplantation Embryos ◽  
Human Embryos ◽  
Adenovirus Receptor

Coxsackie virus and adenovirus receptor,CXADR(CAR), is present during embryogenesis and is involved in tissue regeneration, cancer and intercellular adhesion. We investigated the expression of CAR in human preimplantation embryos and embryonic stem cells (hESC) to identify its role in early embryogenesis and differentiation. CAR protein was ubiquitously present during preimplantation development. It was localised in the nucleus of uncommitted cells, from the cleavage stage up to the precursor epiblast, and corresponded with the presence of solubleCXADR3/7splice variant. CAR was displayed on the membrane, involving in the formation of tight junction at compaction and blastocyst stages in both outer and inner cells, and CAR corresponded with the full-length CAR-containing transmembrane domain. In trophectodermal cells of hatched blastocysts, CAR was reduced in the membrane and concentrated in the nucleus, which correlated with the switch in RNA expression to theCXADR4/7andCXADR2/7splice variants. The cells in the outer layer of hESC colonies contained CAR on the membrane and all the cells of the colony had CAR in the nucleus, corresponding with the transmembraneCXADRandCXADR4/7. Upon differentiation of hESC into cells representing the three germ layers and trophoblast lineage, the expression ofCXADRwas downregulated. We concluded thatCXADRis differentially expressed during human preimplantation development. We described various CAR expressions: i) solubleCXADRmarking undifferentiated blastomeres; ii) transmembrane CAR related with epithelial-like cell types, such as the trophectoderm (TE) and the outer layer of hESC colonies; and iii) soluble CAR present in TE nuclei after hatching. The functions of these distinct forms remain to be elucidated.

scholarly journals SOX17 Is Not Required for the Derivation and Maintenance of Mouse Extraembryonic Endoderm Stem Cell Lines

2022 ◽  
Author(s):  
Xudong Dong ◽  
Ailing Ding ◽  
Jiangwei Lin
Keyword(s):  
Stem Cell ◽  
Cell Lines ◽  
Embryonic Stem ◽  
Cell Lineage ◽  
Preimplantation Embryos ◽  
Primitive Endoderm ◽  
Extraembryonic Endoderm ◽  
Gene Expression Analyses ◽  
Stem Cell Lines

Extraembryonic endoderm stem (XEN) cell lines can be derived and maintained in vitro and reflect the primitive endoderm cell lineage. SOX17 is thought to be required for the derivation and maintenance of mouse XEN cell lines. Here we have re-evaluated this requirement for SOX17. We derived multiple SOX17-deficient XEN cell lines from preimplantation embryos of a SOX17-Cre knockout strain and chemically converted multiple SOX17-deficient embryonic stem cell lines into XEN cell lines by transient culturing with retinoic acid and Activin A. We confirmed the XEN profile of SOX17-deficient cell lines by immunofluorescence with various markers, by NanoString gene expression analyses, and by their contribution to the extraembryonic endoderm of chimeric embryos produced by injecting these cells into blastocysts. Thus, SOX17 is not required for the derivation and maintenance of XEN cell lines.

scholarly journals Human Embryonic Stem Cell-Derived Neural Lineages as In Vitro Models for Screening the Neuroprotective Properties of Lignosus rhinocerus (Cooke) Ryvarden

2019 ◽  
Vol 2019 ◽  
pp. 1-19
Author(s):  
Yin Yeo ◽  
Joash Ban Lee Tan ◽  
Lee Wei Lim ◽  
Kuan Onn Tan ◽  
Boon Chin Heng ◽  
...  
Keyword(s):  
Natural Products ◽  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Neurite Outgrowth ◽  
Human Embryonic Stem Cell ◽  
Methanol Extract ◽  
Embryonic Stem ◽  
Human Stem Cell ◽  
Induced Apoptosis

In the biomedical field, there is growing interest in using human stem cell-derived neurons as in vitro models for pharmacological and toxicological screening of bioactive compounds extracted from natural products. Lignosus rhinocerus (Tiger Milk Mushroom) is used by indigenous communities in Malaysia as a traditional medicine to treat various diseases. The sclerotium of L. rhinocerus has been reported to have medicinal properties, including various bioactivities such as neuritogenic, anti-inflammatory, and anticancer effects. This study aims to investigate the neuroprotective activities of L. rhinocerus sclerotial extracts. Human embryonic stem cell (hESC)-derived neural lineages exposed to the synthetic glucocorticoid, dexamethasone (DEX), were used as the in vitro models. Excess glucocorticoids have been shown to adversely affect fetal brain development and impair differentiation of neural progenitor cells. Screening of different L. rhinocerus sclerotial extracts and DEX on the hESC-derived neural lineages was conducted using cell viability and neurite outgrowth assays. The neuroprotective effects of L. rhinocerus sclerotial extracts against DEX were further evaluated using apoptosis assays and Western blot analysis. Hot aqueous and methanol extracts of L. rhinocerus sclerotium promoted neurite outgrowth of hESC-derived neural stem cells (NSCs) with negligible cytotoxicity. Treatment with DEX decreased viability of NSCs by inducing apoptosis. Coincubation of L. rhinocerus methanol extract with DEX attenuated the DEX-induced apoptosis and reduction in phospho-Akt (pAkt) level in NSCs. These results suggest the involvement of Akt signaling in the neuroprotection of L. rhinocerus methanol extract against DEX-induced apoptosis in NSCs. Methanol extract of L. rhinocerus sclerotium exhibited potential neuroprotective activities against DEX-induced toxicity in hESC-derived NSCs. This study thus validates the use of human stem cell-derived neural lineages as potential in vitro models for screening of natural products with neuroprotective properties.

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