scholarly journals LSD1: Expanding Functions in Stem Cells and Differentiation

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3252
Author(s):  
Carlos Martinez-Gamero ◽  
Sandhya Malla ◽  
Francesca Aguilo
Keyword(s):  
Stem Cells ◽  
Current Knowledge ◽  
Embryonic Stem ◽  
Dependent Manner ◽  
Mammalian Development ◽  
Self Renewal ◽  
Cellular Processes ◽  
Lysine Specific Demethylase ◽  
Induced Pluripotent ◽  
Lysine Demethylase

Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSC) provide a powerful model system to uncover fundamental mechanisms that control cellular identity during mammalian development. Histone methylation governs gene expression programs that play a key role in the regulation of the balance between self-renewal and differentiation of ESCs. Lysine-specific demethylase 1 (LSD1, also known as KDM1A), the first identified histone lysine demethylase, demethylates H3K4me1/2 and H3K9me1/2 at target loci in a context-dependent manner. Moreover, it has also been shown to demethylate non-histone substrates playing a central role in the regulation of numerous cellular processes. In this review, we summarize current knowledge about LSD1 and the molecular mechanism by which LSD1 influences the stem cells state, including the regulatory circuitry underlying self-renewal and pluripotency.

308 Tet1 PLAYS IMPORTANT ROLES IN MAINTAINING CHARACTERIZATIONS OF PORCINE INDUCED PLURIPOTENT STEM CELLS

2013 ◽  
Vol 25 (1) ◽  
pp. 301
Author(s):  
A. R. Fan ◽  
K. Y. Ma ◽  
T. C. Zhao ◽  
P. P. An ◽  
B. Tang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Embryonic Stem ◽  
Embryoid Bodies ◽  
Self Renewal ◽  
Qrt Pcr ◽  
Post Transfection ◽  
Fetal Fibroblasts ◽  
Induced Pluripotent

It was recently found that the ten-eleven-translocation (TET) family of Fe(II) and 2-oxoglutarate-dependent enzymes (Tet1/2/3) can oxidize 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC), and thus promotes active demethylation of genomes. Tet1 is highly expressed in mouse embryonic stem cells (mESC) and has been demonstrated to involve in mESC maintenance. Here we used small interference RNA (siRNA) to transiently knockdown expression of Tet1 in porcine induced pluripotent stem cells (iPSC) in order to identify its functions. The fetal fibroblasts were isolated from a 30-day-old porcine fetus and induced into iPSC with defined transcription factors, namely Oct-4, Sox-2, Klf-4, and C-myc. The colonies appeared on Day 12 and were picked up on Day 14. These colonies had normal ES-like morphology and alkaline phosphatase activity. Specifically, they were positively stained for pluripotency-specific markers, including Oct4, Sox2, Nanog, Rex1, and SSEA1. When cultured in vitro, the cells formed embryoid bodies (EB), and all 3 germ layer markers (endoderm: AFP, alphaAT; mesoderm: BMP4, Enolase; ectoderm: GFAP, Neurod) were detected positively in EB. For siRNA transfections, iPSC from the colonies were transfected with 40 pmol of siRNA and 2 µL of Lipofectamine 2000 in 1 well of a 24-well plate. After transfection, iPSC were subjected to fluorescence-activated cell sorting to determine the fraction of FAM-positive cells in order to confirm transfection efficiency; the percentage of positive cells reached 48 ± 4.96. We observed obvious knockdown of Tet1 after short-term transfection of siRNA, and the knockdown efficiency was confirmed using qRT-PCR and immunofluorescence staining. Notably, knockdown of Tet1 resulted in morphological abnormality and loss of undifferentiated state of porcine iPSC. However, no obvious morphological changes were observed in the negative control (transfected with nonsense-siRNA), positive control (transfected with GAPDH-siRNA), or mock control (transfected with DEPC-treated water). To gain insight into the molecular mechanism underlying the self-renewal defect, we analysed the effects of Tet1 knockdown on the expression of key stem cell factors and differentiation markers of different embryonic layers using qRT-PCR. We found that knockdown of Tet1 resulted in downregulated expression of pluripotency-related genes, such as Lefty-2, Klf-2, and Sox-2 (the expression ratios of post-transfection to pre-transfection were 0.31 ± 0.21, 0.48 ± 0.072, and 0.65 ± 0.046, respectively), and upregulated expression of differentiation-related genes, including Pitx-2, Hand-1, Gata-6, and Lef-1 (the expression ratios of post-transfection to pre-transfection were 4.35 ± 1.36, 2.56 ± 0.68, 2.91 ± 1.47, and 2.33 ± 1.11, respectively). However, Oct-4, C-myc, Klf-4, and Nanog were not downregulated (the expression ratios of post-transfection to pre-transfection were 0.91 ± 0.15, 1.12 ± 0.26, 1.15 ± 0.21, and 1.08 ± 0.08, respectively). Taken together, Tet1 plays important roles in porcine iPSC self-renewal and characterization maintenance. This study was financed by National Basic Research Program of China (NO.2009CB941001).

scholarly journals SALL4 and microRNA: The Role of Let-7

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1301
Author(s):  
Jun Liu ◽  
Madeline A. Sauer ◽  
Shaza Hussein ◽  
Junyu Yang ◽  
Daniel G. Tenen ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem ◽  
Mammalian Development ◽  
Multiple Cancer ◽  
Self Renewal ◽  
Zinc Finger Transcription Factor ◽  
Different Types ◽  
Organ Specific ◽  
Cancer Types

SALL4 is a zinc finger transcription factor that belongs to the spalt-like (SALL) gene fam-ily. It plays important roles in the maintenance of self-renewal and pluripotency of embryonic stem cells, and its expression is repressed in most adult organs. SALL4 re-expression has been observed in different types of human cancers, and dysregulation of SALL4 contributes to the pathogenesis, metastasis, and even drug resistance of multiple cancer types. Surprisingly, little is known regard-ing how SALL4 expression is controlled, but recently microRNAs (miRNAs) have emerged as im-portant regulators of SALL4. Due to the ability of regulating targets differentially in specific tissues, and recent advances in systemic and organ specific miRNA delivery mechanisms, miRNAs have emerged as promising therapeutic targets for cancer treatment. In this review, we summarize cur-rent knowledge of the interaction between SALL4 and miRNAs in mammalian development and cancer, paying particular attention to the emerging roles of the Let-7/Lin28 axis. In addition, we discuss the therapeutic prospects of targeting SALL4 using miRNA-based strategies, with a focus on the Let-7/LIN28 axis.

Reversine: A Synthetic Purine with a Dual Activity as a Cell Dedifferentiating Agent and a Selective Anticancer Drug

2020 ◽  
Vol 27 (21) ◽  
pp. 3448-3462
Author(s):  
Marco Piccoli ◽  
Andrea Ghiroldi ◽  
Michelle M. Monasky ◽  
Federica Cirillo ◽  
Giuseppe Ciconte ◽  
...  
Keyword(s):  
Stem Cells ◽  
Current Knowledge ◽  
Embryonic Stem ◽  
Cell Types ◽  
Cancer Drug ◽  
Anti Cancer ◽  
Adult Cell ◽  
Induced Pluripotent

The development of new therapeutic applications for adult and embryonic stem cells has dominated regenerative medicine and tissue engineering for several decades. However, since 2006, induced Pluripotent Stem Cells (iPSCs) have taken center stage in the field, as they promised to overcome several limitations of the other stem cell types. Nonetheless, other promising approaches for adult cell reprogramming have been attempted over the years, even before the generation of iPSCs. In particular, two years before the discovery of iPSCs, the possibility of synthesizing libraries of large organic compounds, as well as the development of high-throughput screenings to quickly test their biological activity, enabled the identification of a 2,6-disubstituted purine, named reversine, which was shown to be able to reprogram adult cells to a progenitor-like state. Since its discovery, the effect of reversine has been confirmed on different cell types, and several studies on its mechanism of action have revealed its central role in inhibitory activity on several kinases implicated in cell cycle regulation and cytokinesis. These key features, together with its chemical nature, suggested a possible use of the molecule as an anti-cancer drug. Remarkably, reversine exhibited potent cytotoxic activity against several tumor cell lines in vitro and a significant effect in decreasing tumor progression and metastatization in vivo. Thus, 15 years since its discovery, this review aims at critically summarizing the current knowledge to clarify the dual role of reversine as a dedifferentiating agent and anti-cancer drug.

scholarly journals Inducible expression of Oct-3/4 reveals synergy with Klf4 in targeting Cyclin A2 to enhance proliferation during early reprogramming

2021 ◽  
Author(s):  
Lamuk Zaveri ◽  
Jyotsna Dhawan
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Embryonic Stem ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Mesenchymal To Epithelial Transition ◽  
Cyclin A2 ◽  
Slow Cycling ◽  
Induced Pluripotent ◽  
Dose Dependent

AbstractDuring reprogramming of somatic cells, heightened proliferation is one of the earliest changes observed. While other early events such as mesenchymal-to-epithelial transition have been well studied, the mechanisms by which the cell cycle switches from a slow cycling state to a faster cycling state are still incompletely understood. To investigate the role of Oct-3/4 in this early feature of reprogramming, we created a 4-Hydroxytamoxifen dependent Oct-3/4 Estrogen Receptor fusion (OctER). We show that OctER can substitute for Oct-3/4 to reprogram mouse embryonic fibroblasts to induced pluripotent stem cells. While over-expression of OctER or Klf4 individually did not affect cell proliferation, in combination, these factors hasten the cell cycle, in a tamoxifen dose-dependent manner, supporting a key role for OctER. Oct-3/4 + Klf4 increased proliferation by enhancing expression of Cyclin A2. We verified occupancy of endogenous Oct-3/4 and Klf4 at bioinformatically identified binding sites in the Cyclin A2 promoter in mouse embryonic stem cells (mESC). Using inducible OctER along with Klf4, we show dose-dependent induction of Cyclin A2 promoter-reporter activity and mRNA levels. Taken together, our results provide further evidence of the interdependence of pluripotency and the rapid cell cycle seen in mESC, and identify CyclinA2 as a key early target.

scholarly journals Nucleostemin maintains self-renewal of embryonic stem cells and promotes reprogramming of somatic cells to pluripotency

2012 ◽  
Vol 197 (6) ◽  
pp. 731-745 ◽  
Author(s):  
Jian Qu ◽  
J. Michael Bishop
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Embryonic Stem ◽  
Morphological Differentiation ◽  
Ips Cells ◽  
Mammary Epithelial ◽  
Rapid Transit ◽  
Self Renewal ◽  
Induced Pluripotent ◽  
Cell Cycle Inhibitors

Nucleostemin (NS) is a nucleolar GTP-binding protein that was first identified in neural stem cells, the functions of which remain poorly understood. Here, we report that NS is required for mouse embryogenesis to reach blastulation, maintenance of embryonic stem cell (ESC) self-renewal, and mammary epithelial cell (MEC) reprogramming to induced pluripotent stem (iPS) cells. Ectopic NS also cooperates with OCT4 and SOX2 to reprogram MECs and mouse embryonic fibroblasts to iPS cells. NS promotes ESC self-renewal by sustaining rapid transit through the G1 phase of the cell cycle. Depletion of NS in ESCs retards transit through G1 and induces gene expression changes and morphological differentiation through a mechanism that involves the MEK/ERK protein kinases and that is active only during a protracted G1. Suppression of cell cycle inhibitors mitigates these effects. Our results implicate NS in the maintenance of ESC self-renewal, demonstrate the importance of rapid transit through G1 for this process, and expand the known classes of reprogramming factors.

scholarly journals Proteasomes in Protein Homeostasis of Pluripotent Stem Cells

Acta Naturae ◽  
2017 ◽  
Vol 9 (3) ◽  
pp. 39-47 ◽  
Author(s):  
А. V. Selenina ◽  
А. S. Tsimokha ◽  
А. N. Tomilin
Keyword(s):  
Stem Cells ◽  
Regenerative Medicine ◽  
Pluripotent Stem Cells ◽  
Molecular Mechanisms ◽  
Embryonic Stem ◽  
Basic Research ◽  
Ubiquitin Proteasome System ◽  
Protein Homeostasis ◽  
Cellular Processes ◽  
Induced Pluripotent

Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are subjects of high interest not only in basic research, but also in various applied fields, particularly, in regenerative medicine. Despite the tremendous interest to these cells, the molecular mechanisms that control protein homeostasis in these cells remain largely unknown. The ubiquitin-proteasome system (UPS) acts via post-translational protein modifications and protein degradation and, therefore, is involved in the control of virtually all cellular processes: cell cycle, self-renewal, signal transduction, transcription, translation, oxidative stress, immune response, apoptosis, etc. Therefore, studying the biological role and action mechanisms of the UPS in pluripotent cells will help to better understand the biology of cells, as well as to develop novel approaches for regenerative medicine.

scholarly journals Pluripotent Stem Cells for Transgenesis in the Rabbit: A Utopia?

2020 ◽  
Vol 10 (24) ◽  
pp. 8861
Author(s):  
Worawalan Samruan ◽  
Nathalie Beaujean ◽  
Marielle Afanassieff
Keyword(s):  
Stem Cells ◽  
Pluripotent Stem Cells ◽  
Embryonic Stem ◽  
Self Renewal ◽  
Potential Barriers ◽  
Undifferentiated State ◽  
Early Embryos ◽  
Primed State ◽  
Induced Pluripotent ◽  
Intended Use

Pluripotent stem cells (PSCs) possess the following two main properties: self-renewal and pluripotency. Self-renewal is defined as the ability to proliferate in an undifferentiated state and pluripotency as the capacity to differentiate into cells of the three germ layers, i.e., ectoderm, mesoderm, and endoderm. PSCs are derived from early embryos as embryonic stem cells (ESCs) or are produced by reprogramming somatic cells into induced pluripotent stem cells (iPSCs). In mice, PSCs can be stabilized into two states of pluripotency, namely naive and primed. Naive and primed PSCs notably differ by their ability to colonize a host blastocyst to produce germline-competent chimeras; hence, naive PSCs are valuable for transgenesis, whereas primed PSCs are not. Thanks to its physiological and developmental peculiarities similar to those of primates, the rabbit is an interesting animal model for studying human diseases and early embryonic development. Both ESCs and iPSCs have been described in rabbits. They self-renew in the primed state of pluripotency and, therefore, cannot be used for transgenesis. This review presents the available data on the pluripotent state and the chimeric ability of these rabbit PSCs. It also examines the potential barriers that compromise their intended use as producers of germline-competent chimeras and proposes possible alternatives to exploit them for transgenesis.

scholarly journals Induced Pluripotent Stem Cells: Generation Strategy and Epigenetic Mystery behind Reprogramming

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Pengfei Ji ◽  
Sasicha Manupipatpong ◽  
Nina Xie ◽  
Yujing Li
Keyword(s):  
Stem Cells ◽  
Induced Pluripotent Stem Cells ◽  
Pluripotent Stem Cells ◽  
Clinical Medicine ◽  
Ethical Issues ◽  
Somatic Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
Self Renewal ◽  
Induced Pluripotent

Possessing the ability of self-renewal with immortalization and potential for differentiation into different cell types, stem cells, particularly embryonic stem cells (ESC), have attracted significant attention since their discovery. As ESC research has played an essential role in developing our understanding of the mechanisms underlying reproduction, development, and cell (de)differentiation, significant efforts have been made in the biomedical study of ESC in recent decades. However, such studies of ESC have been hampered by the ethical issues and technological challenges surrounding them, therefore dramatically inhibiting the potential applications of ESC in basic biomedical studies and clinical medicine. Induced pluripotent stem cells (iPSCs), generated from the reprogrammed somatic cells, share similar characteristics including but not limited to the morphology and growth of ESC, self-renewal, and potential differentiation into various cell types. The discovery of the iPSC, unhindered by the aforementioned limitations of ESC, introduces a viable alternative to ESC. More importantly, the applications of iPSC in the development of disease models such as neurodegenerative disorders greatly enhance our understanding of the pathogenesis of such diseases and also facilitate the development of clinical therapeutic strategies using iPSC generated from patient somatic cells to avoid an immune rejection. In this review, we highlight the advances in iPSCs generation methods as well as the mechanisms behind their reprogramming. We also discuss future perspectives for the development of iPSC generation methods with higher efficiency and safety.

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