POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem (ES) cells but also acts as a cell fate determinant through a gene dosage effec...POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem (ES) cells but also acts as a cell fate determinant through a gene dosage effect. However, the molecular mechanisms that control the intracellular OCT4 protein level remain elusive. Here, we report that human WWP2, an E3 ubiquitin (Ub)-protein ligase, interacts with OCT4 specifically through its WW domain and enhances Ub modification of OCT4 both in vitro and in vivo. We first demonstrated that endogenous OCT4 in hu- man ES cells can be post-translationally modified by Ub. Furthermore, we found that WWP2 promoted degradation of OCT4 through the 26S proteasome in a dosage-dependent manner, and the active site cysteine residue of WWP2 was required for both its enzymatic activity and proteolytic effect on OCT4. Remarkably, our data show that the en- dogenous OCT4 protein level was significantly elevated when WWP2 expression was downregulated by specific RNA interference (RNAi), suggesting that WWP2 is an important regulator for maintaining a proper OCT4 protein level in human ES cells. Moreover, northern blot analysis showed that the WWP2 transcript was widely present in diverse human tissues/organs and highly expressed in undifferentiated human ES cells. However, its expression level was quickly decreased after human ES cells differentiated, indicating that WWP2 expression might be developmentally regulated. Our findings demonstrate that WWP2 is an important regulator of the OCT4 protein level in human ES cells.展开更多
A paracrine regulation was recently proposed in human embryonic stem cells (hESCs) grown in mouse embryonic fibroblast (MEF)-conditioned media (MEF-CM), where hESCs spontaneously differentiate into autologous fi...A paracrine regulation was recently proposed in human embryonic stem cells (hESCs) grown in mouse embryonic fibroblast (MEF)-conditioned media (MEF-CM), where hESCs spontaneously differentiate into autologous fibroblastlike cells to maintain culture homeostasis by producing TGF-β and insulin-like growth factor-lI (IGF-Ⅱ) in response to basic fibroblast growth factor (bFGF). Although the importance of TGF-β family members in the maintenance of pluripotency of hESCs is widely established, very little is known about the role of IGF-Ⅱ. In order to ease hESC cul- ture conditions and to reduce xenogenic components, we sought (i) to determine whether hESCs can be maintained stable and pluripotent using CM from human foreskin fibroblasts (HFFs) and human mesenchymal stem cells (hM- SCs) rather than MEF-CM, and (ii) to analyze whether the cooperation of bFGF with TGF-β and IGF-Ⅱ to maintain hESCs in MEF-CM may be extrapolated to hESCs maintained in allogeneic mesenchymal stem cell (MSC)-CM and HFF-CM. We found that MSCs and HFFs express all FGF receptors (FGFR1-4) and specifically produce TGF-β in response to bFGF. However, HFFs but not MSCs secrete IGF-Ⅱ. Despite the absence of IGF-Ⅱ in MSC-CM, hESC pluripotency and culture homeostasis were successfully maintained in MSC-CM for over 37 passages. Human ESCs derived on MSCs and hESCs maintained in MSC-CM retained hESC morphology, euploidy, expression of surface markers and transcription factors linked to pluripotency and displayed in vitro and in vivo multilineage developmental potential, suggesting that IGF-Ⅱ may be dispensable for hESC pluripotency. In fact, IGF-Ⅱ blocking had no effect on the homeostasis of hESC cultures maintained either on HFF-CM or on MSC-CM. These data indicate that hESCs are successfully maintained feeder-free with IGF-Ⅱ-lacking MSC-CM, and that the previously proposed paracrine mechanism by which bFGF cooperates with TGF-β and IGF-Ⅱ in the maintenance of hESCs in MEF-CM may not be fully extrapolated to hESCs maintained in CM from human MSCs.展开更多
Objective To observe the impacts of electroacupuncture (EA) on oocyte quality and pregnant outcome for the patients with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization and embryo transfer (IVF...Objective To observe the impacts of electroacupuncture (EA) on oocyte quality and pregnant outcome for the patients with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization and embryo transfer (IVF-ET) and explore its potential mechanism. Methods Sixty-six patients with PCOS and undergoing IVF-ET were divided into two groups randomly, including an observation group (34 cases) and a control group (32 cases). Ethinylestradiol and cyproterone acetate tablets and gonadotropin-releasing hormone agonist were administered for long-program superovulation in either group. In the observation group, the intervention of EA was applied to Guānyuán (关元 CV 4), Zhōngjí (中极 CV 3), Sānyīnjiāo (三阴交 SP 6), Zǐgōng (子宫 EX-CA 1) and Tàixī (太溪 KI 3) additionally for 30 min, once daily, 1 menstrual cycle before controlled ovarian hyperstimulation (COH) and during COH. The pregnant outcome, evaluation of kidney deficiency syndrome, blood hormone level on the day of human chorionic gonadotropin injection and the concentrations of stem cell factor (SCF) in the serum and follicular fluid on the day of oocyte collection were compared between the two groups. Results The score of kidney deficiency symptoms was reduced remarkably after treatment in either group and the improvement in the observation group was superior to that in the control group (P0.01). The fertilization rate [(76.25?±?20.33)% vs (66.34?±?15.44)%], cleavage rate [(98.66?±?3.70)% vs (94.47?±?9.45)%] and the rate of high-quality embryos [(60.20?±?22.20)% vs (50.55?±?16.15)%] in the observation group were all superior to those in the control group separately (all P0.05). Clinical pregnancy rate (46.67%, 14/30) in the observation group was higher than that (37.93%, 11/29) in the control group, but without statistical difference (P0.05). SCF concentrations in the serum and follicular fluid on the day of oocyte collection in the observation group were higher obviously than those in the control group (both P0.05). Conclusion Electroacupuncture plays an active role in the pregnant outcomes of PCOS patients undergoing IVF-ET and it can relieve the symptoms of kidney deficiency in terms of TCM and improve clinical pregnant rate. The mechanism is relevant to the overall adjustment of organic endocrinal system and the local micro-environment of ovary and the improvement of oocyte quality through the up-regulation of SCF concentration.展开更多
Transposable elements(TEs) are mobile genomic sequences of DNA capable of autonomous and nonautonomous duplication. TEs have been highly successful,and nearly half of the human genome now consists of various families ...Transposable elements(TEs) are mobile genomic sequences of DNA capable of autonomous and nonautonomous duplication. TEs have been highly successful,and nearly half of the human genome now consists of various families of TEs. Originally thought to be non-functional,these elements have been co-opted by animal genomes to perform a variety of physiological functions ranging from TE-derived proteins acting directly in normal biological functions, to innovations in transcription factor logic and influence on epigenetic control of gene expression. During embryonic development, when the genome is epigenetically reprogrammed and DNA-demethylated, TEs are released from repression and show embryonic stage-specific expression, and in human and mouse embryos, intact TEderived endogenous viral particles can even be detected. Asimilar process occurs during the reprogramming of somatic cells to pluripotent cells: When the somatic DNA is demethylated, TEs are released from repression. In embryonic stem cells(ESCs), where DNA is hypomethylated, an elaborate system of epigenetic control is employed to suppress TEs, a system that often overlaps with normal epigenetic control of ESC gene expression. Finally, many long non-coding RNAs(lnc RNAs) involved in normal ESC function and those assisting or impairing reprogramming contain multiple TEs in their RNA. These TEs may act as regulatory units to recruit RNA-binding proteins and epigenetic modifiers. This review covers how TEs are interlinked with the epigenetic machinery and lnc RNAs, and how these links influence each other to modulate aspects of ESCs,embryogenesis, and somatic cell reprogramming.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
Hematopoietic stem cells (HSCs), which are localized in the bone marrow of adult mammals, come from hematopoietic endothelium during embryonic stages. Although the basic processes of HSC generation and differentiation...Hematopoietic stem cells (HSCs), which are localized in the bone marrow of adult mammals, come from hematopoietic endothelium during embryonic stages. Although the basic processes of HSC generation and differentiation have been described in the past, the epigenetic regulation of embryonic hematopoiesis remains to be fully described. Here, by utilizing an in vitro differentiation system of mouse embryonic stem cells (ESCs), we identified more than 20 microRNAs that were highly enriched in embryonic hematopoietic cells, including some (e.g. miR-10b, miR-15b, and miR-27a) with previously unknown functions in blood formation. Luciferase and gene expression assays further revealed combinational binding and regulation of these microRNAs by key transcription factors in blood cells. Finally, bioinformatics and functional analyses supported an interactive regulatory control between transcription factors and microRNAs in hematopoiesis.展开更多
基金Acknowledgments We are grateful to Dr DA Melton (Harvard University) for shar- ing his human ES cells with us. The study was supported by grants from the National High Technology Research and Development Program of China (2006CB943900), the National Natural Science Foundation of China (General Program, 30500088), the Shang- hai Jiao Tong University School of Medicine, and the Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences. The study was also supported by the Shanghai Leading Academic Deciline Project (S30201).
文摘POU transcription factor OCT4 not only plays an essential role in maintaining the pluripotent and self-renewing state of embryonic stem (ES) cells but also acts as a cell fate determinant through a gene dosage effect. However, the molecular mechanisms that control the intracellular OCT4 protein level remain elusive. Here, we report that human WWP2, an E3 ubiquitin (Ub)-protein ligase, interacts with OCT4 specifically through its WW domain and enhances Ub modification of OCT4 both in vitro and in vivo. We first demonstrated that endogenous OCT4 in hu- man ES cells can be post-translationally modified by Ub. Furthermore, we found that WWP2 promoted degradation of OCT4 through the 26S proteasome in a dosage-dependent manner, and the active site cysteine residue of WWP2 was required for both its enzymatic activity and proteolytic effect on OCT4. Remarkably, our data show that the en- dogenous OCT4 protein level was significantly elevated when WWP2 expression was downregulated by specific RNA interference (RNAi), suggesting that WWP2 is an important regulator for maintaining a proper OCT4 protein level in human ES cells. Moreover, northern blot analysis showed that the WWP2 transcript was widely present in diverse human tissues/organs and highly expressed in undifferentiated human ES cells. However, its expression level was quickly decreased after human ES cells differentiated, indicating that WWP2 expression might be developmentally regulated. Our findings demonstrate that WWP2 is an important regulator of the OCT4 protein level in human ES cells.
文摘A paracrine regulation was recently proposed in human embryonic stem cells (hESCs) grown in mouse embryonic fibroblast (MEF)-conditioned media (MEF-CM), where hESCs spontaneously differentiate into autologous fibroblastlike cells to maintain culture homeostasis by producing TGF-β and insulin-like growth factor-lI (IGF-Ⅱ) in response to basic fibroblast growth factor (bFGF). Although the importance of TGF-β family members in the maintenance of pluripotency of hESCs is widely established, very little is known about the role of IGF-Ⅱ. In order to ease hESC cul- ture conditions and to reduce xenogenic components, we sought (i) to determine whether hESCs can be maintained stable and pluripotent using CM from human foreskin fibroblasts (HFFs) and human mesenchymal stem cells (hM- SCs) rather than MEF-CM, and (ii) to analyze whether the cooperation of bFGF with TGF-β and IGF-Ⅱ to maintain hESCs in MEF-CM may be extrapolated to hESCs maintained in allogeneic mesenchymal stem cell (MSC)-CM and HFF-CM. We found that MSCs and HFFs express all FGF receptors (FGFR1-4) and specifically produce TGF-β in response to bFGF. However, HFFs but not MSCs secrete IGF-Ⅱ. Despite the absence of IGF-Ⅱ in MSC-CM, hESC pluripotency and culture homeostasis were successfully maintained in MSC-CM for over 37 passages. Human ESCs derived on MSCs and hESCs maintained in MSC-CM retained hESC morphology, euploidy, expression of surface markers and transcription factors linked to pluripotency and displayed in vitro and in vivo multilineage developmental potential, suggesting that IGF-Ⅱ may be dispensable for hESC pluripotency. In fact, IGF-Ⅱ blocking had no effect on the homeostasis of hESC cultures maintained either on HFF-CM or on MSC-CM. These data indicate that hESCs are successfully maintained feeder-free with IGF-Ⅱ-lacking MSC-CM, and that the previously proposed paracrine mechanism by which bFGF cooperates with TGF-β and IGF-Ⅱ in the maintenance of hESCs in MEF-CM may not be fully extrapolated to hESCs maintained in CM from human MSCs.
基金Supported by Natural Science Fund Project of Shandong Province: Y 2007 C 131
文摘Objective To observe the impacts of electroacupuncture (EA) on oocyte quality and pregnant outcome for the patients with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization and embryo transfer (IVF-ET) and explore its potential mechanism. Methods Sixty-six patients with PCOS and undergoing IVF-ET were divided into two groups randomly, including an observation group (34 cases) and a control group (32 cases). Ethinylestradiol and cyproterone acetate tablets and gonadotropin-releasing hormone agonist were administered for long-program superovulation in either group. In the observation group, the intervention of EA was applied to Guānyuán (关元 CV 4), Zhōngjí (中极 CV 3), Sānyīnjiāo (三阴交 SP 6), Zǐgōng (子宫 EX-CA 1) and Tàixī (太溪 KI 3) additionally for 30 min, once daily, 1 menstrual cycle before controlled ovarian hyperstimulation (COH) and during COH. The pregnant outcome, evaluation of kidney deficiency syndrome, blood hormone level on the day of human chorionic gonadotropin injection and the concentrations of stem cell factor (SCF) in the serum and follicular fluid on the day of oocyte collection were compared between the two groups. Results The score of kidney deficiency symptoms was reduced remarkably after treatment in either group and the improvement in the observation group was superior to that in the control group (P0.01). The fertilization rate [(76.25?±?20.33)% vs (66.34?±?15.44)%], cleavage rate [(98.66?±?3.70)% vs (94.47?±?9.45)%] and the rate of high-quality embryos [(60.20?±?22.20)% vs (50.55?±?16.15)%] in the observation group were all superior to those in the control group separately (all P0.05). Clinical pregnancy rate (46.67%, 14/30) in the observation group was higher than that (37.93%, 11/29) in the control group, but without statistical difference (P0.05). SCF concentrations in the serum and follicular fluid on the day of oocyte collection in the observation group were higher obviously than those in the control group (both P0.05). Conclusion Electroacupuncture plays an active role in the pregnant outcomes of PCOS patients undergoing IVF-ET and it can relieve the symptoms of kidney deficiency in terms of TCM and improve clinical pregnant rate. The mechanism is relevant to the overall adjustment of organic endocrinal system and the local micro-environment of ovary and the improvement of oocyte quality through the up-regulation of SCF concentration.
基金supported by the National Natural Science Foundation of China(31471242,31550110206)China Postdoctoral Association(2014M552250)the Science and Technology Planning Project of Guangdong Province,China(2014B030301058)
文摘Transposable elements(TEs) are mobile genomic sequences of DNA capable of autonomous and nonautonomous duplication. TEs have been highly successful,and nearly half of the human genome now consists of various families of TEs. Originally thought to be non-functional,these elements have been co-opted by animal genomes to perform a variety of physiological functions ranging from TE-derived proteins acting directly in normal biological functions, to innovations in transcription factor logic and influence on epigenetic control of gene expression. During embryonic development, when the genome is epigenetically reprogrammed and DNA-demethylated, TEs are released from repression and show embryonic stage-specific expression, and in human and mouse embryos, intact TEderived endogenous viral particles can even be detected. Asimilar process occurs during the reprogramming of somatic cells to pluripotent cells: When the somatic DNA is demethylated, TEs are released from repression. In embryonic stem cells(ESCs), where DNA is hypomethylated, an elaborate system of epigenetic control is employed to suppress TEs, a system that often overlaps with normal epigenetic control of ESC gene expression. Finally, many long non-coding RNAs(lnc RNAs) involved in normal ESC function and those assisting or impairing reprogramming contain multiple TEs in their RNA. These TEs may act as regulatory units to recruit RNA-binding proteins and epigenetic modifiers. This review covers how TEs are interlinked with the epigenetic machinery and lnc RNAs, and how these links influence each other to modulate aspects of ESCs,embryogenesis, and somatic cell reprogramming.
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.
基金supported by the Ministry of Science and Technology of China(2016YFA0100302, 2014CB964800)the National Natural Science Foundation of China (31471347, 30971522, 31271589)the Science and Technology Commission of Shanghai Municipality (11DZ2260300, 13JC1406402,16JC1404200)
文摘Hematopoietic stem cells (HSCs), which are localized in the bone marrow of adult mammals, come from hematopoietic endothelium during embryonic stages. Although the basic processes of HSC generation and differentiation have been described in the past, the epigenetic regulation of embryonic hematopoiesis remains to be fully described. Here, by utilizing an in vitro differentiation system of mouse embryonic stem cells (ESCs), we identified more than 20 microRNAs that were highly enriched in embryonic hematopoietic cells, including some (e.g. miR-10b, miR-15b, and miR-27a) with previously unknown functions in blood formation. Luciferase and gene expression assays further revealed combinational binding and regulation of these microRNAs by key transcription factors in blood cells. Finally, bioinformatics and functional analyses supported an interactive regulatory control between transcription factors and microRNAs in hematopoiesis.