Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of ...Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.展开更多
Nanog is a newly identified homeodomain gene that functions to sustain the pluripotency of embryonic stem cells.However,the molecular mechanism through which nanog regulates stem cell pluripotency remains unknown.Mous...Nanog is a newly identified homeodomain gene that functions to sustain the pluripotency of embryonic stem cells.However,the molecular mechanism through which nanog regulates stem cell pluripotency remains unknown.Mouse nanog encodes a polypeptide of 305 residues with a divergent homeodomain similar to those in the NK-2 family.The rest ofnanog contains no apparent homology to any known proteins characterized so far.It is hypothesized that nanog encodes a transcription factor that regulates stem cell pluripotency by switching on or off target genes.To test this hypothesis,we constructed fusion proteins between nanog and DNA binding domains of the yeast transcription factor Gal4 and tested the transactivation potentials of these constructs.Our data demonstrate that both regions N- and C- terminal to the homeodomain have transcription activities.Despite the fact that it contains no apparent transactivation motifs,the C-terminal domain is about 7 times as active as the N-terminal one.This unique arrangement of dual transactivators may confer nanog the flexibility and specificity to regulate downstream genes critical for both pluripotency and differentiation of stem cells.展开更多
Several extrinsic signals such as LIF, BMP and Wnt can support the self-renewal and pluripotency of embryonic stem （ES） cells through regulating the ＂pluripotent genes.＂ A unique homeobox transcription factor, Nan...Several extrinsic signals such as LIF, BMP and Wnt can support the self-renewal and pluripotency of embryonic stem （ES） cells through regulating the ＂pluripotent genes.＂ A unique homeobox transcription factor, Nanog, is one of the key downstream effectors of these signals. Elevated level of Nanog can maintain the mouse ES cell self-renewal independent of LIF and enable human ES cell growth without feeder cells. In addition to the external signal pathways, intrinsic transcription factors such as FoxD3, P53 and Oct4 are also involved in regulating the expression of Nanog. Functionally, Nanog works together with other key pluripotent factors such as Oct4 and Sox2 to control a set of target genes that have important functions in ES cell pluripotency. These key factors form a regulatory network to support or limit each other＇s expression level, which maintains the properties of ES cells.展开更多
Sex determining region Y-box 2(Sox2), a member of the SoxB1 transcription factor family, is an important transcriptional regulator in pluripotent stem cells(PSCs). Together with octamer-binding transcription factor 4 ...Sex determining region Y-box 2(Sox2), a member of the SoxB1 transcription factor family, is an important transcriptional regulator in pluripotent stem cells(PSCs). Together with octamer-binding transcription factor 4 and Nanog, they co-operatively control gene expression in PSCs and maintain their pluripotency. Furthermore, Sox2 plays an essential role in somatic cell reprogram-ming, reversing the epigenetic configuration of differ-entiated cells back to a pluripotent embryonic state. In addition to its role in regulation of pluripotency, Sox2 is also a critical factor for directing the differentiation of PSCs to neural progenitors and for maintaining the properties of neural progenitor stem cells. Here, we review recent findings concerning the involvement of Sox2 in pluripotency, somatic cell reprogramming and neural differentiation as well as the molecular mecha-nisms underlying these roles.展开更多
LIN28A,an RNA-binding protein,plays an important role in porcine induced pluripotent stem cells(piPSCs).However,the molecular mechanism underlying the function of LIN28A in the maintenance of pluripotency in piPSCs re...LIN28A,an RNA-binding protein,plays an important role in porcine induced pluripotent stem cells(piPSCs).However,the molecular mechanism underlying the function of LIN28A in the maintenance of pluripotency in piPSCs remains unclear.Here,we explored the function of LIN28A in piPSCs based on its overexpression and knockdown.We performed total RNA sequencing(RNA-seq)of piPSCs and detected the expression levels of relevant genes by quantitative real-time polymerase chain reaction(qRT-PCR),western blot analysis,and immunofluorescence staining.Results indicated that piPSC proliferation ability decreased following LIN28A knockdown.Furthermore,when LIN28A expression in the shLIN28A2 group was lower(by 20%)than that in the negative control knockdown group(shNC),the pluripotency of piPSCs disappeared and they differentiated into neuroectoderm cells.Results also showed that LIN28A overexpression inhibited the expression of DUSP(dual-specificity phosphatases)family phosphatases and activated the mitogen-activated protein kinase(MAPK)signaling pathway.Thus,LIN28A appears to activate the MAPK signaling pathway to maintain the pluripotency and proliferation ability of piPSCs.Our study provides a new resource for exploring the functions of LIN28A in piPSCs.展开更多
Background: Acquisition of pluripotency by transcriptional regulatory factors is an initial developmental event that is required for regulation of cell fate and lineage specification during early embryonic development...Background: Acquisition of pluripotency by transcriptional regulatory factors is an initial developmental event that is required for regulation of cell fate and lineage specification during early embryonic development. The evolutionarily conserved core transcriptional factors regulating the pluripotency network in fishes, amphibians, and mammals have been elucidated. There are also species-specific maternally inherited transcriptional factors and their intricate transcriptional networks important in the acquisition of pluripotency. In avian species, however, the core transcriptional network that governs the acquisition of pluripotency during early embryonic development is not well understood.Results: We found that chicken NANOG(c NANOG) was expressed in the stages between the pre-ovulatory follicle and oocyte and was continuously detected in Eyal-Giladi and Kochav stage I(EGK.I) to X. However, c POUV was not expressed during fol iculogenesis, but began to be detectable between EGK.V and VI. Unexpectedly, c SOX2 could not be detected during fol iculogenesis and intrauterine embryonic development. Instead of c SOX2, c SOX3 was maternally inherited and continuously expressed during chicken intrauterine development. In addition, we found that the pluripotency-related genes such as c ENS-1, c KIT, c LIN28 A, c MYC, c PRDM14, and c SALL4 began to be dramatical y upregulated between EGK.VI and VII.Conclusion: These results suggest that chickens have a unique pluripotent circuitry since maternally inherited c NANOG and c SOX3 may play an important role in the initial acquisition of pluripotency. Moreover, the acquisition of pluripotency in chicken embryos occurs at around EGK.VI to VI I.展开更多
Stem cell pluripotency and differentiation are global processes regulated by several pathways that have been studied intensively over recent years. Nitric oxide(NO) is an important molecule that affects gene expressio...Stem cell pluripotency and differentiation are global processes regulated by several pathways that have been studied intensively over recent years. Nitric oxide(NO) is an important molecule that affects gene expression at the level of transcription and translation and regulates cell survival and proliferation in diverse cell types. In embryonic stem cells NO has a dual role, controlling differentiation and survival, but the molecular mechanisms by which it modulates these functions are not completely defined. NO is a physiological regulator of cell respiration through the inhibition of cytochrome c oxidase. Many researchers have been examining the role that NO plays in other aspects of metabolism such as the cellular bioenergetics state, the hypoxia response and the relationship of these areas to stem cell stemness.展开更多
Biological reactions require self-assembly of factors in the complex cellular milieu.Recent evidence indicates that intrinsically disordered,low-complexity sequence domains(LCDs)found in regulatory factors mediate div...Biological reactions require self-assembly of factors in the complex cellular milieu.Recent evidence indicates that intrinsically disordered,low-complexity sequence domains(LCDs)found in regulatory factors mediate diverse cellular processes from gene expression to DNA repair to signal transduction,by enriching specific biomolecules in membraneless compartments or hubs that may undergo liquidliquid phase separation(LLPS).In this review,we discuss how embryonic stem cells take advantage of LCD-driven interactions to promote cell-specific transcription,DNA damage response,and DNA repair.We propose that LCDmediated interactions play key roles in stem cell maintenance and safeguarding genome integrity.展开更多
BACKGROUND The generation of induced pluripotent stem cells(iPSC)has been a game-changer in translational and regenerative medicine;however,their large-scale applicability is still hampered by the scarcity of accessib...BACKGROUND The generation of induced pluripotent stem cells(iPSC)has been a game-changer in translational and regenerative medicine;however,their large-scale applicability is still hampered by the scarcity of accessible,safe,and reproducible protocols.The porcine model is a large biomedical model that enables translational applications,including gene editing,long term in vivo and offspring analysis;therefore,suitable for both medicine and animal production.AIM To reprogramme in vitro into pluripotency,and herein urine-derived cells(UDCs)were isolated from porcine urine.METHODS The UDCs were reprogrammed in vitro using human or murine octamer-binding transcription factor 4(OCT4),SRY-box2(SOX2),Kruppel-like factor 4(KLF4),and C-MYC,and cultured with basic fibroblast growth factor(bFGF)supplementation.To characterize the putative porcine iPSCs three clonal lineages were submitted to immunocytochemistry for alkaline phosphatase(AP),OCT4,SOX2,NANOG,TRA181 and SSEA 1 detection.Endogenous transcripts related to the pluripotency(OCT4,SOX2 and NANOG)were analyzed via reverse transcription quantitative realtime polymerase chain reaction in different time points during the culture,and all three lineages formed embryoid bodies(EBs)when cultured in suspension without bFGF supplementation.RESULTS The UDCs were isolated from swine urine samples and when at passage 2 submitted to in vitro reprogramming.Colonies of putative iPSCs were obtained only from UDCs transduced with the murine factors(mOSKM),but not from human factors(hOSKM).Three clonal lineages were isolated and further cultured for at least 28 passages,all the lineages were positive for AP detection,the OCT4,SOX2,NANOG markers,albeit the immunocytochemical analysis also revealed heterogeneous phenotypic profiles among lineages and passages for NANOG and SSEA1,similar results were observed in the abundance of the endogenous transcripts related to pluripotent state.All the clonal lineages when cultured in suspension without bFGF were able to form EBs expressing ectoderm and mesoderm layers transcripts.CONCLUSION For the first time UDCs were isolated in the swine model and reprogrammed into a pluripotentlike state,enabling new numerous applications in both human or veterinary regenerative medicine.展开更多
Epigenetic reprogramming of somatic cells into induced pluripotent stem cells （iPSCs） by overexpression of defined factors holds great promise for disease modeling and regen- erative medicine （Takahashi and Yamanak...Epigenetic reprogramming of somatic cells into induced pluripotent stem cells （iPSCs） by overexpression of defined factors holds great promise for disease modeling and regen- erative medicine （Takahashi and Yamanaka, 2006; Robinton and Daley, 2012）. However, the stochastic reprogramming process often results in variable pluripotency levels of iPSC lines as measured by their in vivo developmental potential, which poses a huge challenge to the applications of high quality iPSCs （Hanna et al., 2010）. The activation status of an imprinted Dlkl-Dio3 region has been identified as a molecular marker for pluripotency （Liu et al., 2010; Stadtfeld et al.,展开更多
Embryonic stem (ES) cell biology is attracting much attention in cell biology because of their pluripotent behaviors and potential therapeutic applications. However,what maintains ES cell pluripotency and what trigger...Embryonic stem (ES) cell biology is attracting much attention in cell biology because of their pluripotent behaviors and potential therapeutic applications. However,what maintains ES cell pluripotency and what triggers ES cell展开更多
To explore the pluripotency maintenance and update the functional influence of pluripotency genes cNanog and cPouV in chicken （ C,a/lus gallus） embry- onic stem cells （ cESCs）, the stable RNAi vectors pSuper-cNano...To explore the pluripotency maintenance and update the functional influence of pluripotency genes cNanog and cPouV in chicken （ C,a/lus gallus） embry- onic stem cells （ cESCs）, the stable RNAi vectors pSuper-cNanog and pSuper-cPouV constructed previously were used to transfect cESCs. The mRNA levels of two target genes were detected with real- time PCR. These two genes were down-regulated since the 48^th and the down-reg-lation continued with the extension of time, the interference efficiency reached 65% at 96^th hour （P 〈0.05）. With the down-regulation of cNanog or cPouV gene, cESCs showed differentiation and prolifera- tion rate of these cells slowed down, the domed colony of these cells disappeared gradually when the edge of colony became irregular. At 96^th hour after transfection, the alkline phosphatase （AKP） and stage-specific embryonic antigen-1 （ SSEA-1 ） were not be detected in cNanog gene-knecked out eESCs, but it was done in that with cPouV gene -knocked out. The cPouV-suppressing cESCs were again transfected with pSuper-cNanog, the pluripotency markers AKP and SSEA-1 were both not found expressing at the 48^th hour. The results showed that cPouV and cNartog genes played an important role in maintaining pluripotency and self- renewal in cESCs, and cNanog gene was dominant. To sum up, our results may provide insights into the molecular regulation mechanism of avian during development.展开更多
Recent studies have demonstrated that differentiated somatic cells from various mammalian species can be reprogrammed into induced pluripotent stem （iPS） cells by the ectopic expression of four transcription factors...Recent studies have demonstrated that differentiated somatic cells from various mammalian species can be reprogrammed into induced pluripotent stem （iPS） cells by the ectopic expression of four transcription factors that are highly expressed in embryonic stem （ES） cells. The generation of patient-specific iPS cells directly from somatic cells without using oocytes or embryos holds great promise for curing numerous diseases that are currently unresponsive to traditional clinical approaches. However, some recent studies have argued that various iPS cell lines may still retain certain epigenetic memories that are inherited from the somatic cells. Such observations have raised concerns regarding the safety and efficacy of using iPS cell derivatives for clinical applications. Recently, our study demonstrated full pluripotency of mouse iPS cells by tetraploid complementation, indicating that it is possible to obtain fully reprogrammed iPS cells directly from differentiated somatic cells. Therefore, we propose in this review that further comprehensive studies of both mouse and human iPS cells are required so that additional information will be available for evaluating the quality of human iPS cells.展开更多
Cellular reprogramming and induced pluripotent stem cell(IPSC) technology demonstrated the plasticity of adult cell fate, opening a new era of cellular modelling and introducing a versatile therapeutic tool for regene...Cellular reprogramming and induced pluripotent stem cell(IPSC) technology demonstrated the plasticity of adult cell fate, opening a new era of cellular modelling and introducing a versatile therapeutic tool for regenerative medicine.While IPSCs are already involved in clinical trials for various regenerative purposes, critical questions concerning their medium-and long-term genetic and epigenetic stability still need to be answered. Pluripotent stem cells have been described in the last decades in various mammalian and human tissues(such as bone marrow, blood and adipose tissue). We briefly describe the characteristics of human-derived adult stem cells displaying in vitro and/or in vivo pluripotency while highlighting that the common denominators of their isolation or occurrence within tissue are represented by extreme cellular stress. Spontaneous cellular reprogramming as a survival mechanism favoured by senescence and cellular scarcity could represent an adaptative mechanism. Reprogrammed cells could initiate tissue regeneration or tumour formation dependent on the microenvironment characteristics. Systems biology approaches and lineage tracing within living tissues can be used to clarify the origin of adult pluripotent stem cells and their significance for regeneration and disease.展开更多
Oct4 is one of the key pluripotent factors essential for embryonic stem cells and induced pluripotent stem （iPS） cells. Oct4 belongs to the POU domain family, which contains multiples genes with various important fu...Oct4 is one of the key pluripotent factors essential for embryonic stem cells and induced pluripotent stem （iPS） cells. Oct4 belongs to the POU domain family, which contains multiples genes with various important functions. Although the function of Oct4 has been extensively studied, detailed comparison of Oct4 with other POU family genes and their evolutionary analysis are still lacking. Here, we systematically identified POU family genes from lower to higher animal species. We observed an expansion of POU family genes in vertebrates, with an additional increment in mammalian genomes. We analyzed the phylogenetic relationship, tissue specific expression profiles and regulatory networks of POU family genes of the human genome, and predicted the putative binding microRNAs of human POU family genes. These results provide the first comprehensive evolutionary and comparative analysis of POU family genes, which will help to better understand the relationships among POU family genes and shed light on their future functional studies.展开更多
Primordial germ cells(PGCs) are precursors of all gametes, and represent the founder cells of the germline. Although developmental potency is restricted to germ-lineage cells, PGCs can be reprogrammed into a pluripote...Primordial germ cells(PGCs) are precursors of all gametes, and represent the founder cells of the germline. Although developmental potency is restricted to germ-lineage cells, PGCs can be reprogrammed into a pluripotent state. Specifically, PGCs give rise to germ cell tumors, such as testicular teratomas, in vivo, and to pluripotent stem cells known as embryonic germ cells in vitro. In this review, we highlight the current knowledge on signaling pathways, transcriptional controls, and post-transcriptional controls that govern germ cell differentiation and de-differentiation. These regulatory processes are common in the reprogramming of germ cells and somatic cells, and play a role in the pathogenesis of human germ cell tumors.展开更多
Post-translational modifications(PTMs)are dynamic processes that regulate cell states by enhancing proteome diversity.However,the overall impact of PTMs on pluripotency exit in porcine embryonic stem cells(pESCs)remai...Post-translational modifications(PTMs)are dynamic processes that regulate cell states by enhancing proteome diversity.However,the overall impact of PTMs on pluripotency exit in porcine embryonic stem cells(pESCs)remains largely unknown.Here,we present a systematic assay to identify E3 ubiquitin ligases for pluripotency exit by using CRISPR/Cas9 pooled screening and identified PIAS4 as a major regulator of pluripotency exit,as the cell differentiation was significantly impaired upon PIAS4 depletion in pESCs.PIAS4 shows a high degree of genomic occupation in promoter regions,particularly in key pluripotency maintenance genes.Moreover,we found that PIAS4 was recruited to the gene promoter marked by H3K4me3 and interacted with lysine demethylase KDM5B via SUMOylation,thereby affecting the stability of KDM5B and further facilitating the regulation of H3K4me3-mediated lineage-specific genes.Together,our findings reveal a regulatory mechanism by which PIAS4 modulates H3K4me3 modification on development-related genes,subsequently influencing pluripotency exit and cell fate commitment by interacting with KDM5B in pESCs.展开更多
Semiconductor quantum dots(QDs)hold increasing potential for cellular imaging both in vitro and in vivo.In this report,we aimed to study imaging of human embryonic stem(ES)cells labeled with quantum dots(QDs),and to e...Semiconductor quantum dots(QDs)hold increasing potential for cellular imaging both in vitro and in vivo.In this report,we aimed to study imaging of human embryonic stem(ES)cells labeled with quantum dots(QDs),and to evaluate the viability and pluripotency of human ES cells labeled with QDs.We used the Tat-QDs to label human ES cells,evaluated the cytoactivity of human ES cells labeled with QDs by CCK8 assay and Flow cytometer,and verified the pluripotency of human ES cells labeled with QDs by differentiated the human ES cells into hemangioblasts/blast cells and neural-like cells.The result illustrated that human embryonic stem(ES)cells were labeled with QDs and intracellular QD number was associated with the dose of QDs.Human ES cell viability,proliferation,and pluripotency were not adversely affected by QDs compared with non-labeled control cells.In summary,this is the first report showing the QDs labeled human ES cells could be differentiated into hemangioblasts/blast cells and neural-like cells.These results provide a promising tool for imaging stem cell therapy noninvasively in vivo.展开更多
Long-term in vitro maintenance of embryonic stem cell (ESC) pluripotency enables the pluripotency and differentiation of ESCs in animals to be investigated. The ability to successfully maintain and differentiate chick...Long-term in vitro maintenance of embryonic stem cell (ESC) pluripotency enables the pluripotency and differentiation of ESCs in animals to be investigated. The ability to successfully maintain and differentiate chicken embryonic stem cells (cESCs) would provide a useful tool for avian biology research and would be a resource directly applicable to agricultural production. In this study, endogenous chicken pluripotency transcription factors, POUV, Sox-2, Nanog and Lin28 were cloned and expressed as recombinant proteins containing a nine consecutive arginine protein transduction domain (PTD). cESCs were cultured with these recombinant proteins to maintain cESC pluripotency in vitro. Cultured cESCs exhibited typical characteristics of pluripotency, even after six generations of rapid doubling, including positive staining for stage-specific embryonic antigen I, and strong staining for alkaline phosphatase. Expression levels of the pluripotency markers, POUV, Nanog, C-Myc, Sox-2 and Lin28 were the same as in uncultured stage X blastoderm cells, and most significantly, the formation of embryoid bodies (EBs) by 6th generation cESCs confirmed the ability of these cultured cESCs to differentiate into cells of all three embryonic germ layers. Thus, transcription factors could be translocated through the cell membrane into the intracellular space of cESCs by using a PTD of nine consecutive arginines and the pluripotency of cESCs could be maintained in vitro for at least six generations.展开更多
Pluripotency is depicted by a self-renewing state that can competently differentiate to form the three germ layers.Different stages of early murine development can be captured on a petri dish,delineating a spectrum of...Pluripotency is depicted by a self-renewing state that can competently differentiate to form the three germ layers.Different stages of early murine development can be captured on a petri dish,delineating a spectrum of pluripotent states,ranging from embryonic stem cells,embryonic germ cells to epiblast stem cells.Anomalous cell populations displaying signs of pluripotency have also been uncovered,from the isolation of embryonic carcinoma cells to the derivation of induced pluripotent stem cells.Gaining insight into the molecular circuitry within these cell types enlightens us about the significance and contribution of each stage,hence deepening our understanding of vertebrate development.In this review,we aim to describe experimental milestones that led to the understanding of embryonic development and the conception of pluripotency.We also discuss attempts at exploring the realm of pluripotency with the identification of pluripotent stem cells within mouse teratocarcinomas and embryos,and the generation of pluripotent cells through nuclear reprogramming.In conclusion,we illustrate pluripotent cells derived from other organisms,including human derivatives,and describe current paradigms in the comprehension of human pluripotency.展开更多
文摘Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.
基金supported in part by the Tsinghua University BaiRen Scholar Program,NSFC 30270287the 973 Project--2001CB5101 from The Ministry of Science and Technology of China.
文摘Nanog is a newly identified homeodomain gene that functions to sustain the pluripotency of embryonic stem cells.However,the molecular mechanism through which nanog regulates stem cell pluripotency remains unknown.Mouse nanog encodes a polypeptide of 305 residues with a divergent homeodomain similar to those in the NK-2 family.The rest ofnanog contains no apparent homology to any known proteins characterized so far.It is hypothesized that nanog encodes a transcription factor that regulates stem cell pluripotency by switching on or off target genes.To test this hypothesis,we constructed fusion proteins between nanog and DNA binding domains of the yeast transcription factor Gal4 and tested the transactivation potentials of these constructs.Our data demonstrate that both regions N- and C- terminal to the homeodomain have transcription activities.Despite the fact that it contains no apparent transactivation motifs,the C-terminal domain is about 7 times as active as the N-terminal one.This unique arrangement of dual transactivators may confer nanog the flexibility and specificity to regulate downstream genes critical for both pluripotency and differentiation of stem cells.
文摘Several extrinsic signals such as LIF, BMP and Wnt can support the self-renewal and pluripotency of embryonic stem （ES） cells through regulating the ＂pluripotent genes.＂ A unique homeobox transcription factor, Nanog, is one of the key downstream effectors of these signals. Elevated level of Nanog can maintain the mouse ES cell self-renewal independent of LIF and enable human ES cell growth without feeder cells. In addition to the external signal pathways, intrinsic transcription factors such as FoxD3, P53 and Oct4 are also involved in regulating the expression of Nanog. Functionally, Nanog works together with other key pluripotent factors such as Oct4 and Sox2 to control a set of target genes that have important functions in ES cell pluripotency. These key factors form a regulatory network to support or limit each other＇s expression level, which maintains the properties of ES cells.
文摘Sex determining region Y-box 2(Sox2), a member of the SoxB1 transcription factor family, is an important transcriptional regulator in pluripotent stem cells(PSCs). Together with octamer-binding transcription factor 4 and Nanog, they co-operatively control gene expression in PSCs and maintain their pluripotency. Furthermore, Sox2 plays an essential role in somatic cell reprogram-ming, reversing the epigenetic configuration of differ-entiated cells back to a pluripotent embryonic state. In addition to its role in regulation of pluripotency, Sox2 is also a critical factor for directing the differentiation of PSCs to neural progenitors and for maintaining the properties of neural progenitor stem cells. Here, we review recent findings concerning the involvement of Sox2 in pluripotency, somatic cell reprogramming and neural differentiation as well as the molecular mecha-nisms underlying these roles.
基金This work was supported by the National Key Research,Development Program of China-Stem Cell and Translational Research(2016YFA0100200)National Natural Science Foundation of China(32072806,31572399,61772431,62072377)+1 种基金Program of Shaanxi Province Science and Technology Innovation Team(2019TD-036)Fundamental Research Funds for the Central Universities,Northwest A&F University(Z1090219146,Z102022004)。
文摘LIN28A,an RNA-binding protein,plays an important role in porcine induced pluripotent stem cells(piPSCs).However,the molecular mechanism underlying the function of LIN28A in the maintenance of pluripotency in piPSCs remains unclear.Here,we explored the function of LIN28A in piPSCs based on its overexpression and knockdown.We performed total RNA sequencing(RNA-seq)of piPSCs and detected the expression levels of relevant genes by quantitative real-time polymerase chain reaction(qRT-PCR),western blot analysis,and immunofluorescence staining.Results indicated that piPSC proliferation ability decreased following LIN28A knockdown.Furthermore,when LIN28A expression in the shLIN28A2 group was lower(by 20%)than that in the negative control knockdown group(shNC),the pluripotency of piPSCs disappeared and they differentiated into neuroectoderm cells.Results also showed that LIN28A overexpression inhibited the expression of DUSP(dual-specificity phosphatases)family phosphatases and activated the mitogen-activated protein kinase(MAPK)signaling pathway.Thus,LIN28A appears to activate the MAPK signaling pathway to maintain the pluripotency and proliferation ability of piPSCs.Our study provides a new resource for exploring the functions of LIN28A in piPSCs.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(No.2015R1A3A2033826)the International Research&Development Program of the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future Planning of Korea(NRF-2016K1A3A1A21005676)
文摘Background: Acquisition of pluripotency by transcriptional regulatory factors is an initial developmental event that is required for regulation of cell fate and lineage specification during early embryonic development. The evolutionarily conserved core transcriptional factors regulating the pluripotency network in fishes, amphibians, and mammals have been elucidated. There are also species-specific maternally inherited transcriptional factors and their intricate transcriptional networks important in the acquisition of pluripotency. In avian species, however, the core transcriptional network that governs the acquisition of pluripotency during early embryonic development is not well understood.Results: We found that chicken NANOG(c NANOG) was expressed in the stages between the pre-ovulatory follicle and oocyte and was continuously detected in Eyal-Giladi and Kochav stage I(EGK.I) to X. However, c POUV was not expressed during fol iculogenesis, but began to be detectable between EGK.V and VI. Unexpectedly, c SOX2 could not be detected during fol iculogenesis and intrauterine embryonic development. Instead of c SOX2, c SOX3 was maternally inherited and continuously expressed during chicken intrauterine development. In addition, we found that the pluripotency-related genes such as c ENS-1, c KIT, c LIN28 A, c MYC, c PRDM14, and c SALL4 began to be dramatical y upregulated between EGK.VI and VII.Conclusion: These results suggest that chickens have a unique pluripotent circuitry since maternally inherited c NANOG and c SOX3 may play an important role in the initial acquisition of pluripotency. Moreover, the acquisition of pluripotency in chicken embryos occurs at around EGK.VI to VI I.
基金Grants from Consejería de Igualdad,Salud y Politicas Sociales,Junta de Andalucía,No.PI105/2010Consejería de Economía,Innovación,Ciencia y Empleo,Junta de Andalucía,No.CTS-7127/2011(to Bedoya FJ)+6 种基金Consejería de Igualdad,Salud y Políticas Sociales,Junta de Andalucía,ISCIII co-funded by Fondos FEDER(RED TERCEL),No.RD06/0010/0025,RD12/0019/0028 and PI10/00964Consejería de Economía,Innovación,Ciencia y Empleo,No.P10.CTS.6505the Ministry of Health and Consumer Affairs(Advanced Therapies Program Grant TRA-120)(to Soria B)Consejería de Igualdad,Salud y Políticas Sociales,No.PI0022/2008Consejería de Economía,Innovación,Ciencia y Empleo,Junta de Andalucía(PAI,BIO311)(to Martín F)Servicio Andaluz de Salud(SAS 11245)Ministerio de Economía y Competitividad-Secretaría de Estado de Investigación Desarrollo e Innovación,No.IPT-2011-1615-900000(to Tejedo JR)
文摘Stem cell pluripotency and differentiation are global processes regulated by several pathways that have been studied intensively over recent years. Nitric oxide(NO) is an important molecule that affects gene expression at the level of transcription and translation and regulates cell survival and proliferation in diverse cell types. In embryonic stem cells NO has a dual role, controlling differentiation and survival, but the molecular mechanisms by which it modulates these functions are not completely defined. NO is a physiological regulator of cell respiration through the inhibition of cytochrome c oxidase. Many researchers have been examining the role that NO plays in other aspects of metabolism such as the cellular bioenergetics state, the hypoxia response and the relationship of these areas to stem cell stemness.
基金Supported by National Institute of Health,No.R01HL125527.
文摘Biological reactions require self-assembly of factors in the complex cellular milieu.Recent evidence indicates that intrinsically disordered,low-complexity sequence domains(LCDs)found in regulatory factors mediate diverse cellular processes from gene expression to DNA repair to signal transduction,by enriching specific biomolecules in membraneless compartments or hubs that may undergo liquidliquid phase separation(LLPS).In this review,we discuss how embryonic stem cells take advantage of LCD-driven interactions to promote cell-specific transcription,DNA damage response,and DNA repair.We propose that LCDmediated interactions play key roles in stem cell maintenance and safeguarding genome integrity.
基金the São Paulo Research Foundation(FAPESP)-Brazil(financial support grants#2015/26818-5,#2013/08135-2,#2019/02811-2)Coordination of Superior Level Staff Improvement(CAPES 23038.006964/2014-43 and financial code 001)National Council for Scientific and Technological Development(CNPq 433133/2018-0).
文摘BACKGROUND The generation of induced pluripotent stem cells(iPSC)has been a game-changer in translational and regenerative medicine;however,their large-scale applicability is still hampered by the scarcity of accessible,safe,and reproducible protocols.The porcine model is a large biomedical model that enables translational applications,including gene editing,long term in vivo and offspring analysis;therefore,suitable for both medicine and animal production.AIM To reprogramme in vitro into pluripotency,and herein urine-derived cells(UDCs)were isolated from porcine urine.METHODS The UDCs were reprogrammed in vitro using human or murine octamer-binding transcription factor 4(OCT4),SRY-box2(SOX2),Kruppel-like factor 4(KLF4),and C-MYC,and cultured with basic fibroblast growth factor(bFGF)supplementation.To characterize the putative porcine iPSCs three clonal lineages were submitted to immunocytochemistry for alkaline phosphatase(AP),OCT4,SOX2,NANOG,TRA181 and SSEA 1 detection.Endogenous transcripts related to the pluripotency(OCT4,SOX2 and NANOG)were analyzed via reverse transcription quantitative realtime polymerase chain reaction in different time points during the culture,and all three lineages formed embryoid bodies(EBs)when cultured in suspension without bFGF supplementation.RESULTS The UDCs were isolated from swine urine samples and when at passage 2 submitted to in vitro reprogramming.Colonies of putative iPSCs were obtained only from UDCs transduced with the murine factors(mOSKM),but not from human factors(hOSKM).Three clonal lineages were isolated and further cultured for at least 28 passages,all the lineages were positive for AP detection,the OCT4,SOX2,NANOG markers,albeit the immunocytochemical analysis also revealed heterogeneous phenotypic profiles among lineages and passages for NANOG and SSEA1,similar results were observed in the abundance of the endogenous transcripts related to pluripotent state.All the clonal lineages when cultured in suspension without bFGF were able to form EBs expressing ectoderm and mesoderm layers transcripts.CONCLUSION For the first time UDCs were isolated in the swine model and reprogrammed into a pluripotentlike state,enabling new numerous applications in both human or veterinary regenerative medicine.
基金supported by the grants from the "Strategic Priority Research Program" of the Chinese Academy of Sciences (No. XDA01020100 to Q.Z.)the China National Basic Research Program (No. 2012CBA01300 to Q.Z.)the National Science Foundation of China (No. 91319308 to Q.Z.,31201105 to L.L. and 31371516 to W.L.)
文摘Epigenetic reprogramming of somatic cells into induced pluripotent stem cells （iPSCs） by overexpression of defined factors holds great promise for disease modeling and regen- erative medicine （Takahashi and Yamanaka, 2006; Robinton and Daley, 2012）. However, the stochastic reprogramming process often results in variable pluripotency levels of iPSC lines as measured by their in vivo developmental potential, which poses a huge challenge to the applications of high quality iPSCs （Hanna et al., 2010）. The activation status of an imprinted Dlkl-Dio3 region has been identified as a molecular marker for pluripotency （Liu et al., 2010; Stadtfeld et al.,
文摘Embryonic stem (ES) cell biology is attracting much attention in cell biology because of their pluripotent behaviors and potential therapeutic applications. However,what maintains ES cell pluripotency and what triggers ES cell
基金Supported by National Natural Science Foundation of China(No.31072101No.31201871)Natural Science Foundation of Guangdong Province
文摘To explore the pluripotency maintenance and update the functional influence of pluripotency genes cNanog and cPouV in chicken （ C,a/lus gallus） embry- onic stem cells （ cESCs）, the stable RNAi vectors pSuper-cNanog and pSuper-cPouV constructed previously were used to transfect cESCs. The mRNA levels of two target genes were detected with real- time PCR. These two genes were down-regulated since the 48^th and the down-reg-lation continued with the extension of time, the interference efficiency reached 65% at 96^th hour （P 〈0.05）. With the down-regulation of cNanog or cPouV gene, cESCs showed differentiation and prolifera- tion rate of these cells slowed down, the domed colony of these cells disappeared gradually when the edge of colony became irregular. At 96^th hour after transfection, the alkline phosphatase （AKP） and stage-specific embryonic antigen-1 （ SSEA-1 ） were not be detected in cNanog gene-knecked out eESCs, but it was done in that with cPouV gene -knocked out. The cPouV-suppressing cESCs were again transfected with pSuper-cNanog, the pluripotency markers AKP and SSEA-1 were both not found expressing at the 48^th hour. The results showed that cPouV and cNartog genes played an important role in maintaining pluripotency and self- renewal in cESCs, and cNanog gene was dominant. To sum up, our results may provide insights into the molecular regulation mechanism of avian during development.
基金supported by the Ministry of Science and Technology of China(grants 2008AA022311,2010CB944900 and 2011CB964800)
文摘Recent studies have demonstrated that differentiated somatic cells from various mammalian species can be reprogrammed into induced pluripotent stem （iPS） cells by the ectopic expression of four transcription factors that are highly expressed in embryonic stem （ES） cells. The generation of patient-specific iPS cells directly from somatic cells without using oocytes or embryos holds great promise for curing numerous diseases that are currently unresponsive to traditional clinical approaches. However, some recent studies have argued that various iPS cell lines may still retain certain epigenetic memories that are inherited from the somatic cells. Such observations have raised concerns regarding the safety and efficacy of using iPS cell derivatives for clinical applications. Recently, our study demonstrated full pluripotency of mouse iPS cells by tetraploid complementation, indicating that it is possible to obtain fully reprogrammed iPS cells directly from differentiated somatic cells. Therefore, we propose in this review that further comprehensive studies of both mouse and human iPS cells are required so that additional information will be available for evaluating the quality of human iPS cells.
文摘Cellular reprogramming and induced pluripotent stem cell(IPSC) technology demonstrated the plasticity of adult cell fate, opening a new era of cellular modelling and introducing a versatile therapeutic tool for regenerative medicine.While IPSCs are already involved in clinical trials for various regenerative purposes, critical questions concerning their medium-and long-term genetic and epigenetic stability still need to be answered. Pluripotent stem cells have been described in the last decades in various mammalian and human tissues(such as bone marrow, blood and adipose tissue). We briefly describe the characteristics of human-derived adult stem cells displaying in vitro and/or in vivo pluripotency while highlighting that the common denominators of their isolation or occurrence within tissue are represented by extreme cellular stress. Spontaneous cellular reprogramming as a survival mechanism favoured by senescence and cellular scarcity could represent an adaptative mechanism. Reprogrammed cells could initiate tissue regeneration or tumour formation dependent on the microenvironment characteristics. Systems biology approaches and lineage tracing within living tissues can be used to clarify the origin of adult pluripotent stem cells and their significance for regeneration and disease.
基金supported by the grants from the Ministry of Science and Technology of China(No.2011CBA01101 to X.-J.W.)the Chinese Academy of Sciences(Nos. XDA01020105,KSCX2-EW-R-01-03 and 2010-Biols-CAS- 0303 to X.-J.W.)
文摘Oct4 is one of the key pluripotent factors essential for embryonic stem cells and induced pluripotent stem （iPS） cells. Oct4 belongs to the POU domain family, which contains multiples genes with various important functions. Although the function of Oct4 has been extensively studied, detailed comparison of Oct4 with other POU family genes and their evolutionary analysis are still lacking. Here, we systematically identified POU family genes from lower to higher animal species. We observed an expansion of POU family genes in vertebrates, with an additional increment in mammalian genomes. We analyzed the phylogenetic relationship, tissue specific expression profiles and regulatory networks of POU family genes of the human genome, and predicted the putative binding microRNAs of human POU family genes. These results provide the first comprehensive evolutionary and comparative analysis of POU family genes, which will help to better understand the relationships among POU family genes and shed light on their future functional studies.
基金Supported by Grants-in-Aid for Scientific Research from the Ministry of Education,Culture,Sports,Science and Technology(MEXT)of Japan and Takeda Science Foundation
文摘Primordial germ cells(PGCs) are precursors of all gametes, and represent the founder cells of the germline. Although developmental potency is restricted to germ-lineage cells, PGCs can be reprogrammed into a pluripotent state. Specifically, PGCs give rise to germ cell tumors, such as testicular teratomas, in vivo, and to pluripotent stem cells known as embryonic germ cells in vitro. In this review, we highlight the current knowledge on signaling pathways, transcriptional controls, and post-transcriptional controls that govern germ cell differentiation and de-differentiation. These regulatory processes are common in the reprogramming of germ cells and somatic cells, and play a role in the pathogenesis of human germ cell tumors.
基金supported by the National Key R&D Program of China(2022YFD1302200)Scientific Innovation 2030 Project(2023ZD04072,2023ZD0404703)+2 种基金the Natural Science Foundation of Hubei Province(2022CFB149)the Fundamental Research Funds for the Central Universities(2662023DKPY001)the Special Research Project on Experimental Animal of Hubei Province(2023CFA006).
文摘Post-translational modifications(PTMs)are dynamic processes that regulate cell states by enhancing proteome diversity.However,the overall impact of PTMs on pluripotency exit in porcine embryonic stem cells(pESCs)remains largely unknown.Here,we present a systematic assay to identify E3 ubiquitin ligases for pluripotency exit by using CRISPR/Cas9 pooled screening and identified PIAS4 as a major regulator of pluripotency exit,as the cell differentiation was significantly impaired upon PIAS4 depletion in pESCs.PIAS4 shows a high degree of genomic occupation in promoter regions,particularly in key pluripotency maintenance genes.Moreover,we found that PIAS4 was recruited to the gene promoter marked by H3K4me3 and interacted with lysine demethylase KDM5B via SUMOylation,thereby affecting the stability of KDM5B and further facilitating the regulation of H3K4me3-mediated lineage-specific genes.Together,our findings reveal a regulatory mechanism by which PIAS4 modulates H3K4me3 modification on development-related genes,subsequently influencing pluripotency exit and cell fate commitment by interacting with KDM5B in pESCs.
基金supported by the National Natural Science Foundation of China(No.20803040 and No.20471599)Chinese 973 Project(2010CB933901)+3 种基金New Century Excellent Talent of Ministry of Education of China(NCET-08-0350)Special Infection Diseases Key Project of China(2009ZX10004-311)Shanghai Science and Technology Fund(10XD1406100)Doctoral Program of Higher Education Research Fund(20070248050,20070248107).
文摘Semiconductor quantum dots(QDs)hold increasing potential for cellular imaging both in vitro and in vivo.In this report,we aimed to study imaging of human embryonic stem(ES)cells labeled with quantum dots(QDs),and to evaluate the viability and pluripotency of human ES cells labeled with QDs.We used the Tat-QDs to label human ES cells,evaluated the cytoactivity of human ES cells labeled with QDs by CCK8 assay and Flow cytometer,and verified the pluripotency of human ES cells labeled with QDs by differentiated the human ES cells into hemangioblasts/blast cells and neural-like cells.The result illustrated that human embryonic stem(ES)cells were labeled with QDs and intracellular QD number was associated with the dose of QDs.Human ES cell viability,proliferation,and pluripotency were not adversely affected by QDs compared with non-labeled control cells.In summary,this is the first report showing the QDs labeled human ES cells could be differentiated into hemangioblasts/blast cells and neural-like cells.These results provide a promising tool for imaging stem cell therapy noninvasively in vivo.
基金assisted by the National Key Lab of Agro Biotechnology
文摘Long-term in vitro maintenance of embryonic stem cell (ESC) pluripotency enables the pluripotency and differentiation of ESCs in animals to be investigated. The ability to successfully maintain and differentiate chicken embryonic stem cells (cESCs) would provide a useful tool for avian biology research and would be a resource directly applicable to agricultural production. In this study, endogenous chicken pluripotency transcription factors, POUV, Sox-2, Nanog and Lin28 were cloned and expressed as recombinant proteins containing a nine consecutive arginine protein transduction domain (PTD). cESCs were cultured with these recombinant proteins to maintain cESC pluripotency in vitro. Cultured cESCs exhibited typical characteristics of pluripotency, even after six generations of rapid doubling, including positive staining for stage-specific embryonic antigen I, and strong staining for alkaline phosphatase. Expression levels of the pluripotency markers, POUV, Nanog, C-Myc, Sox-2 and Lin28 were the same as in uncultured stage X blastoderm cells, and most significantly, the formation of embryoid bodies (EBs) by 6th generation cESCs confirmed the ability of these cultured cESCs to differentiate into cells of all three embryonic germ layers. Thus, transcription factors could be translocated through the cell membrane into the intracellular space of cESCs by using a PTD of nine consecutive arginines and the pluripotency of cESCs could be maintained in vitro for at least six generations.
文摘Pluripotency is depicted by a self-renewing state that can competently differentiate to form the three germ layers.Different stages of early murine development can be captured on a petri dish,delineating a spectrum of pluripotent states,ranging from embryonic stem cells,embryonic germ cells to epiblast stem cells.Anomalous cell populations displaying signs of pluripotency have also been uncovered,from the isolation of embryonic carcinoma cells to the derivation of induced pluripotent stem cells.Gaining insight into the molecular circuitry within these cell types enlightens us about the significance and contribution of each stage,hence deepening our understanding of vertebrate development.In this review,we aim to describe experimental milestones that led to the understanding of embryonic development and the conception of pluripotency.We also discuss attempts at exploring the realm of pluripotency with the identification of pluripotent stem cells within mouse teratocarcinomas and embryos,and the generation of pluripotent cells through nuclear reprogramming.In conclusion,we illustrate pluripotent cells derived from other organisms,including human derivatives,and describe current paradigms in the comprehension of human pluripotency.
