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Chen Y, Li M, Wu Y. The occurrence and development of induced pluripotent stem cells. Front Genet 2024; 15:1389558. [PMID: 38699229 PMCID: PMC11063328 DOI: 10.3389/fgene.2024.1389558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 04/08/2024] [Indexed: 05/05/2024] Open
Abstract
The ectopic expression of four transcription factors, Oct3/4, Sox2, Klf4, and c-Myc (OSKM), known as "Yamanaka factors," can reprogram or stimulate the production of induced pluripotent stem cells (iPSCs). Although OSKM is still the gold standard, there are multiple ways to reprogram cells into iPSCs. In recent years, significant progress has been made in improving the efficiency of this technology. Ten years after the first report was published, human pluripotent stem cells have gradually been applied in clinical settings, including disease modeling, cell therapy, new drug development, and cell derivation. Here, we provide a review of the discovery of iPSCs and their applications in disease and development.
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Affiliation(s)
| | - Meng Li
- Department of Cardiology, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yanqing Wu
- Department of Cardiology, The Second Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, China
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Tai L, Huang CJ, Choo KB, Cheong SK, Kamarul T. Oxidative Stress Down-Regulates MiR-20b-5p, MiR-106a-5p and E2F1 Expression to Suppress the G1/S Transition of the Cell Cycle in Multipotent Stromal Cells. Int J Med Sci 2020; 17:457-470. [PMID: 32174776 PMCID: PMC7053300 DOI: 10.7150/ijms.38832] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 12/30/2019] [Indexed: 12/24/2022] Open
Abstract
Oxidative stress has been linked to senescence and tumorigenesis via modulation of the cell cycle. Using a hydrogen peroxide (H2O2)-induced oxidative stress-induced premature senescence (OSIPS) model previously reported by our group, this study aimed to investigate the effects of oxidative stress on microRNA (miRNA) expression in relation to the G1-to-S-phase (G1/S) transition of the cell cycle and cell proliferation. On global miRNA analysis of the OSIPS cells, twelve significantly up- or down-regulated miRNAs were identified, the target genes of which are frequently associated with cancers. Four down-regulated miR-17 family miRNAs are predicted to target key pro- and anti-proliferative proteins of the p21/cyclin D-dependent kinase (CDK)/E2F1 pathway to modulate G1/S transition. Two miR-17 miRNAs, miR-20-5p and miR-106-5p, were confirmed to be rapidly and stably down-regulated under oxidative stress. While H2O2 treatment hampered G1/S transition and suppressed DNA synthesis, miR-20b-5p/miR-106a-5p over-expression rescued cells from growth arrest in promoting G1/S transition and DNA synthesis. Direct miR-20b-5p/miR-106a-5p regulation of p21, CCND1 and E2F1 was demonstrated by an inverse expression relationship in miRNA mimic-transfected cells. However, under oxidative stress, E2F1 expression was down-regulated, consistent with hampered G1/S transition and suppressed DNA synthesis and cell proliferation. To explain the observed E2F1 down-regulation under oxidative stress, a scheme is proposed which includes miR-20b-5p/miR-106a-5p-dependent regulation, miRNA-E2F1 autoregulatory feedback and E2F1 response to repair oxidative stress-induced DNA damages. The oxidative stress-modulated expression of miR-17 miRNAs and E2F1 may be used to develop strategies to retard or reverse MSC senescence in culture, or senescence in general.
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Affiliation(s)
- Lihui Tai
- Centre for Stem Cell Research, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia.,Postgraduate Program, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
| | - Chiu-Jung Huang
- Department of Animal Science & Graduate Institute of Biotechnology, Chinese Culture University, Taipei, Taiwan
| | - Kong Bung Choo
- Centre for Stem Cell Research, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia.,Department of Preclinical Sciences, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
| | - Soon Keng Cheong
- Centre for Stem Cell Research, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia.,Dean's Office, Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
| | - Tunku Kamarul
- Tissue Engineering Group, National Orthopedic Centre of Excellence for Research and Learning & Department of Orthopedic Surgery, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
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De Robertis M, Poeta ML, Signori E, Fazio VM. Current understanding and clinical utility of miRNAs regulation of colon cancer stem cells. Semin Cancer Biol 2018; 53:232-247. [PMID: 30130662 DOI: 10.1016/j.semcancer.2018.08.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 08/10/2018] [Accepted: 08/17/2018] [Indexed: 02/07/2023]
Abstract
Cancer stem cells (CSCs) in colorectal tumorigenesis are suggested to be responsible for initiation, development and propagation of colorectal cancer (CRC) and have been extensively characterized by the expression of phenotypic determinants, such as surface or intracellular proteins. The generation of CSCs is likely due to a dysregulation of the signaling pathways that principally control self-renewal and pluripotency in normal intestinal stem cells (ISCs) through different (epi)genetic changes that define cell fate, identity, and phenotype of CSCs. These aspects are currently under intense investigation. In the framework of the oncogenic signaling pathways controlled by microRNAs (miRNAs) during CRC development, a plethora of data suggests that miRNAs can play a key role in several regulatory pathways involving CSCs biology, epithelial-mesenchymal transition (EMT), angiogenesis, metastatization, and pharmacoresistance. This review examines the most relevant evidences about the role of miRNAs in the etiology of CRC, through the regulation of colon CSCs and the principal differences between colorectal CSCs and benign stem cells. In this perspective, the utility of the principal CSCs-related miRNAs changes is explored, emphasizing their use as potential biomarkers to aid in diagnosis, prognosis and predicting response to therapy in CRC patients, but also as promising targets for more effective and personalized anti-CRC treatments.
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Affiliation(s)
- Mariangela De Robertis
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari "A. Moro", Via Orabona 4, 70126 Bari, Italy; Laboratory of Molecular Medicine and Biotechnology, University Campus Bio-Medico of Rome, Via Alvaro del Portillo 21, 00128 Rome, Italy; Laboratory of Molecular Pathology and Experimental Oncology, Institute of Translational Pharmacology, Consiglio Nazionale delle Ricerche (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy.
| | - Maria Luana Poeta
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari "A. Moro", Via Orabona 4, 70126 Bari, Italy
| | - Emanuela Signori
- Laboratory of Molecular Medicine and Biotechnology, University Campus Bio-Medico of Rome, Via Alvaro del Portillo 21, 00128 Rome, Italy; Laboratory of Molecular Pathology and Experimental Oncology, Institute of Translational Pharmacology, Consiglio Nazionale delle Ricerche (CNR), Via Fosso del Cavaliere 100, 00133 Rome, Italy.
| | - Vito Michele Fazio
- Laboratory of Molecular Medicine and Biotechnology, University Campus Bio-Medico of Rome, Via Alvaro del Portillo 21, 00128 Rome, Italy; IRCCS "Casa Sollievo della Sofferenza", viale dei Cappuccini, 71013 San Giovanni Rotondo (FG), Italy
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Comparison of the MicroRNA Expression Profiles of Male and Female Avian Primordial Germ Cell Lines. Stem Cells Int 2018; 2018:1780679. [PMID: 30123283 PMCID: PMC6079386 DOI: 10.1155/2018/1780679] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 05/08/2018] [Accepted: 06/03/2018] [Indexed: 11/18/2022] Open
Abstract
Primordial germ cells (PGCs) are the precursors of adult germ cells, and among the embryonic stem-like cells in the bird embryo, only they can transmit the genetic information to the next generation. Despite the wide range of applications, very little is known about the mechanism that governs primordial germ cell self-renewal and differentiation. As a first step, we compared 12 newly established chicken PGC lines derived from two different chicken breeds, performing CCK-8 proliferation assay. All of the lines were derived from individual embryos. A significant difference was found among the lines. As microRNAs have been proved to play a key role in the maintenance of pluripotency and the cell cycle regulation of stem cells, we continued with a complex miRNA analysis. We could discover miRNAs expressing differently in PGC lines with high proliferation rate, compared to PGC lines with low proliferation rate. We found that gga-miR-2127 expresses differently in female and male cell lines. The microarray analysis also revealed high expression level of the gga-miR-302b-3p strand (member of the miR-302/367 cluster) in slowly proliferating PGC lines compared to the gga-miR-302b-5p strand. We confirmed that the inhibition of miR-302b-5p significantly increases the doubling time of the examined PGC lines. In conclusion, we found that gga-miR-181-5p, gga-miR-2127, and members of the gga-miR-302/367 cluster have a dominant role in the regulation of avian primordial germ cell proliferation.
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Hao J, Duan FF, Wang Y. MicroRNAs and RNA binding protein regulators of microRNAs in the control of pluripotency and reprogramming. Curr Opin Genet Dev 2017; 46:95-103. [PMID: 28753462 DOI: 10.1016/j.gde.2017.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 06/19/2017] [Accepted: 07/11/2017] [Indexed: 12/09/2022]
Abstract
Post-transcriptional and translational regulations play essential roles during cellular reprogramming and in the maintenance and differentiation of pluripotent stem cells (PSCs). MicroRNAs (miRNAs) control cell cycle, glycolysis, chromatin state, survival and pluripotency of ESCs. Likewise, many miRNAs assist or act as a barrier for the generation of induced pluripotent stem cells (iPSCs). Recent studies also reveal exciting new directions on miRNA functions in regulating the switch between naive and primed pluripotent states as well as the establishment of totipotent-like state. Furthermore, the biogenesis and function of pluripotency related miRNAs are regulated by various RNA binding proteins (RBPs) at different levels. Revealing the interplay between RBPs and miRNAs will advance our understanding of molecular mechanisms controlling pluripotency and provide better means to manipulate PSCs for clinical applications. In this review, we summarize recent findings on the function of miRNAs in ESCs and during reprogramming. In addition, we also discuss new directions on miRNA functions in regulating the switch between different pluripotent states and RBP-mediated regulation of miRNA biogenesis and function in pluripotency control.
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Affiliation(s)
- Jing Hao
- Beijing Key Laboratory of Cardio Metabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Fei-Fei Duan
- Beijing Key Laboratory of Cardio Metabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China
| | - Yangming Wang
- Beijing Key Laboratory of Cardio Metabolic Molecular Medicine, Institute of Molecular Medicine, Peking University, Beijing, China.
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Transdifferentiation and reprogramming: Overview of the processes, their similarities and differences. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017; 1864:1359-1369. [PMID: 28460880 DOI: 10.1016/j.bbamcr.2017.04.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 04/24/2017] [Accepted: 04/26/2017] [Indexed: 12/24/2022]
Abstract
Reprogramming, or generation of induced pluripotent stem (iPS) cells (functionally similar to embryonic stem cells or ES cells) by the use of transcription factors (typically: Oct3/4, Sox2, c-Myc, Klf4) called "Yamanaka factors" (OSKM), has revolutionized regenerative medicine. However, factors used to induce stemness are also overexpressed in cancer. Both, ES cells and iPS cells cause teratoma formation when injected to tissues. This raises a safety concern for therapies based on iPS derivates. Transdifferentiation (lineage reprogramming, or -conversion), is a process in which one mature, specialized cell type changes into another without entering a pluripotent state. This process involves an ectopic expression of transcription factors and/or other stimuli. Unlike in the case of reprogramming, tissues obtained by this method do not carry the risk of subsequent teratomagenesis.
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Mamoori A, Gopalan V, Smith RA, Lam AKY. Modulatory roles of microRNAs in the regulation of different signalling pathways in large bowel cancer stem cells. Biol Cell 2016; 108:51-64. [DOI: 10.1111/boc.201500062] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 12/21/2015] [Indexed: 02/06/2023]
Affiliation(s)
- Afraa Mamoori
- Cancer Molecular Pathology, School of Medicine, Menzies Health Institute Queensland; Griffith University; Gold Coast Queensland Australia
- Department of Pathology and Forensic Medicine, College of Medicine; University of Babylon; Iraq
| | - Vinod Gopalan
- Cancer Molecular Pathology, School of Medicine, Menzies Health Institute Queensland; Griffith University; Gold Coast Queensland Australia
| | - Robert Anthony Smith
- Genomics Research Centre, Institute for Health and Biomedical Innovation; Queensland University of Technology; Queensland Australia
| | - Alfred King-Yin Lam
- Cancer Molecular Pathology, School of Medicine, Menzies Health Institute Queensland; Griffith University; Gold Coast Queensland Australia
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Horiguchi H, Kobune M, Kikuchi S, Yoshida M, Murata M, Murase K, Iyama S, Takada K, Sato T, Ono K, Hashimoto A, Tatekoshi A, Kamihara Y, Kawano Y, Miyanishi K, Sawada N, Kato J. Extracellular vesicle miR-7977 is involved in hematopoietic dysfunction of mesenchymal stromal cells via poly(rC) binding protein 1 reduction in myeloid neoplasms. Haematologica 2016; 101:437-47. [PMID: 26802051 DOI: 10.3324/haematol.2015.134932] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 01/15/2016] [Indexed: 11/09/2022] Open
Abstract
The failure of normal hematopoiesis is observed in myeloid neoplasms. However, the precise mechanisms governing the replacement of normal hematopoietic stem cells in their niche by myeloid neoplasm stem cells have not yet been clarified. Primary acute myeloid leukemia and myelodysplastic syndrome cells induced aberrant expression of multiple hematopoietic factors including Jagged-1, stem cell factor and angiopoietin-1 in mesenchymal stem cells even in non-contact conditions, and this abnormality was reverted by extracellular vesicle inhibition. Importantly, the transfer of myeloid neoplasm-derived extracellular vesicles reduced the hematopoietic supportive capacity of mesenchymal stem cells. Analysis of extracellular vesicle microRNA indicated that several species, including miR-7977 from acute myeloid leukemia cells, were higher than those from normal CD34(+)cells. Remarkably, the copy number of miR-7977 in bone marrow interstitial fluid was elevated not only in acute myeloid leukemia, but also in myelodysplastic syndrome, as compared with lymphoma without bone marrow localization. The transfection of the miR-7977 mimic reduced the expression of the posttranscriptional regulator, poly(rC) binding protein 1, in mesenchymal stem cells. Moreover, the miR-7977 mimic induced aberrant reduction of hematopoietic growth factors in mesenchymal stem cells, resulting in decreased hematopoietic-supporting capacity of bone marrow CD34(+)cells. Furthermore, the reduction of hematopoietic growth factors including Jagged-1, stem cell factor and angiopoietin-1 were reverted by target protection of poly(rC) binding protein 1, suggesting that poly(rC) binding protein 1 could be involved in the stabilization of several growth factors. Thus, miR-7977 in extracellular vesicles may be a critical factor that induces failure of normal hematopoiesis via poly(rC) binding protein 1 suppression.
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Affiliation(s)
- Hiroto Horiguchi
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Masayoshi Kobune
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Shohei Kikuchi
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Masahiro Yoshida
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Masaki Murata
- Department of Pathology, Sapporo Medical University School of Medicine, Japan
| | - Kazuyuki Murase
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Satoshi Iyama
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Kohichi Takada
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Tsutomu Sato
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Kaoru Ono
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Akari Hashimoto
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Ayumi Tatekoshi
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Yusuke Kamihara
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Yutaka Kawano
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Koji Miyanishi
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
| | - Norimasa Sawada
- Department of Pathology, Sapporo Medical University School of Medicine, Japan
| | - Junji Kato
- Department of Medical Oncology and Hematology, Sapporo Medical University School of Medicine, Japan
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Ribecco-Lutkiewicz M, Ly D, Sodja C, Haukenfrers J, Smith B, Liu QY, Sikorska M, Bani-Yaghoub M. MicroRNA Expression in Amniotic Fluid Cells. FETAL STEM CELLS IN REGENERATIVE MEDICINE 2016. [DOI: 10.1007/978-1-4939-3483-6_11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Çağlayan ES, Güran Ş. Importance of Myc-related microRNAs in induced pluripotency. Cell Biol Int 2015; 39:987-94. [PMID: 25809132 DOI: 10.1002/cbin.10467] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Accepted: 03/14/2015] [Indexed: 01/23/2023]
Abstract
Pluripotent stem cells (PSCs) have the capacity to differentiate into any cell type of the body. Therefore, induced pluripotent stem cells (iPSCs) are seen as a promising solution for patient-specific cell therapies. However, the safety is major issue for in vitro methods that are used in induction of pluripotency and also in differentiation of PSCs toward specific cell types. In pioneer studies of iPSC generation, the role of c-Myc has been highlighted as a possible master regulator of pluripotency, but direct c-Myc overexpression is known to prompt drawbacks, especially in human cells. In recent studies, the role of non-protein coding RNA molecules such as microRNAs (miRNAs) has been shown in enhanced reprogramming efficiency. In addition, new reprogramming methods have been ultimately improved by adding miRNAs, in the absence of previous factors. Cross interaction between miRNAs and c-Myc has been also found in differentiation of iPSCs, as well as in reprogramming and self-renewing the pluripotent state. Thence, miRNAs are promising solution for efficiency and safety of iPSC derivation and differentiation methods. The purpose of the present review is to evaluate interaction mechanisms of miRNAs with c-Myc and in iPSC technology.
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Affiliation(s)
- E Sacide Çağlayan
- Nutrition and Dietetics Department, Yildirim Beyazıt University, Health Science Faculty, Ankara, Turkey
| | - Şefik Güran
- Medical Biology Department, Gulhane Military Medicine Academy, Ankara, Turkey
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Large noncoding RNAs are promising regulators in embryonic stem cells. J Genet Genomics 2015; 42:99-105. [PMID: 25819086 DOI: 10.1016/j.jgg.2015.02.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 12/31/2022]
Abstract
Embryonic stem cells (ESCs) hold great promises for treating and studying numerous devastating diseases. The molecular basis of their potential is not completely understood. Large noncoding RNAs (lncRNAs) are an important class of gene regulators that play essential roles in a variety of physiologic and pathologic processes. Dozens of lncRNAs are now identified to control ESC self-renewal and differentiation. Research on lncRNAs may provide novel insights into manipulating the cell fate or reprogramming somatic cells into induced pluripotent stem cells (iPSCs). In this review, we summarize the recent research efforts in identifying functional lncRNAs and understanding how they act in ESCs, and discuss various future directions of this field.
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Suppression of epithelial-mesenchymal transition and apoptotic pathways by miR-294/302 family synergistically blocks let-7-induced silencing of self-renewal in embryonic stem cells. Cell Death Differ 2014; 22:1158-69. [PMID: 25501598 PMCID: PMC4572863 DOI: 10.1038/cdd.2014.205] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 10/27/2014] [Accepted: 11/03/2014] [Indexed: 01/01/2023] Open
Abstract
The embryonic stem cell (ESC)-enriched miR-294/302 family and the somatic cell-enriched let-7 family stabilizes the self-renewing and differentiated cell fates, respectively. The mechanisms underlying these processes remain unknown. Here we show that among many pathways regulated by miR-294/302, the combinatorial suppression of epithelial–mesenchymal transition (EMT) and apoptotic pathways is sufficient in maintaining the self-renewal of ESCs. The silencing of ESC self-renewal by let-7 was accompanied by the upregulation of several EMT regulators and the induction of apoptosis. The ectopic activation of either EMT or apoptotic program is sufficient in silencing ESC self-renewal. However, only combined but not separate suppression of the two programs inhibited the silencing of ESC self-renewal by let-7 and several other differentiation-inducing miRNAs. These findings demonstrate that combined repression of the EMT and apoptotic pathways by miR-294/302 imposes a synergistic barrier to the silencing of ESC self-renewal, supporting a model whereby miRNAs regulate complicated cellular processes through synergistic repression of multiple targets or pathways.
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