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【Objective】 Utilizing a specially engineered miR-144-GFP-H1 human embryonic stem cell (hESC) reporter line, this study leverages GFP fluorescence as an indicator of miR-144 expression to gauge the progression of erythropoiesis. The investigation is aimed at elucidating the potential roles of lncRNAs within the erythropoietic framework and conducting an initial assessment of their functional impact. 【Methods】 The miR-144/451-GFP-H1 cell line (hereafter referred to as 144-H1) was utilized for in vitro erythrocyte induction culture. The subpopulations of cells entering the erythropoiesis stage were characterized by the surface molecules CD71 and GPA. The GFP reporter gene of miR-144 served as a critical determinant to distinguish between GFP-positive cells (with a high propensity for erythropoiesis) and GFP-negative cells (with a low propensity for erythropoiesis). Transcriptome sequencing was performed on both groups to identify differentially expressed long non-coding RNAs (lncRNAs). LncRNA entries with potential for validation were selected for preliminary functional verification. The CRISPR/Cas9 gene editing technique was employed to design functional interference strategies for the targeted lncRNAs, obtaining 144-H1 cell lines with knocked-out function of the specific lncRNAs. These knockout cell lines, along with non-knockout 144-H1 cell lines, were used for parallel erythrocyte induction culture to identify differential nodes. This approach preliminarily verified their impact on erythropoiesis in an in vitro development model. 【Results】 1)The constructed 144-H1 cell line was capable of expressing GFP fluorescence upon entering the stage of in vitro erythrocyte induction, indicating the activation of miR-144/451. 2)Within the CD71, GPA double-positive group, significant differences in lncRNA expression were observed between the GFP-positive and GFP-negative subpopulations. 3) Gene editing strategies involving the deletion of sequence segments capable of effectively interfering with the function of multiple lncRNA entries were designed and verified for successful editing. In the knockout cell lines, parts of the lncRNA sequences were directly deleted. 4)In parallel validation experiments of erythrocyte induction culture, cell lines with LINC01569 knocked out exhibited significant differences in flow cytometric subpopulations and cell proliferation capabilities compared to the non-knockout cell lines: ①The knockout cell lines showed sustained high expression of GFP fluorescence. ②The proportion of the CD71-GPA double-positive group in the knockout cell lines continuously decreased during erythrocyte maturation. ③No significant expression of hemoglobin was observed in the knockout cell lines, lacking the characteristic red color. ④The cell proliferation capability of the knockout cell lines was significantly lower than that of the non-knockout cell lines (P<0.05). 【Conclusion】 The successful employment of the 144-H1 cell line facilitated an exploration into the potential functions of lncRNAs in erythropoiesis. This enables the design of more refined in vitro developmental experiments to enhance the precision in capturing lncRNA functions. Among the differentially expressed lncRNA entries, LINC01569 was preliminarily validated to play a regulatory role in erythropoiesis. The functional absence of LINC01569 severely impacts the normal differentiation and proliferation of erythrocytes. The specific regulatory mechanism of LINC01569 in erythropoiesis warrants further investigation and research.
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One of the main challenges of tissue engineering in dentistry is to replace bone and dental tissues with strategies or techniques that simulate physiological tissue repair conditions. This systematic review of in vitro studies aimed to evaluate the influence of the addition of nanohydroxyapatite (NHap) to scaffolds on cell proliferation and osteogenic and odontogenic differentiation of human mesenchymal stem cells. In vitro studies on human stem cells that proliferated and differentiated into odontogenic and osteogenic cells in scaffolds containing NHap were included in this study. Searches in PubMed/MEDLINE, Scopus, Web of Science, OpenGrey, ProQuest, and Cochrane Library electronic databases were performed. The total of 333 articles was found across all databases. After reading and analyzing titles and abstracts, 8 articles were selected for full reading and extraction of qualitative data. Results showed that despite the large variability in scaffold composition, NHap-containing scaffolds promoted high rates of cell proliferation, increased alkaline phosphatase (ALP) activity during short culture periods, and induced differentiation, as evidenced by the high expression of genes involved in osteogenesis and odontogenesis. However, further studies with greater standardization regarding NHap concentration, type of scaffolds, and evaluation period are needed to observe possible interference of these criteria in the action of NHap on the proliferation and differentiation of human stem cells.
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This study explores the effects of enhancing the definitive hematopoiesis(DH)signals during the differentiation of human embryonic stem cells(hESCs)into hematopoietic stem/progenitor cells on the generation efficiency and effector function of natural killer(NK)cells generated from hESCs(also known as hESC-NK cells).The hESC(H1)were transformed into embryoid bodies(Ebs)by centrifugation,and during the induction of K562,were used to analyze the efficiency of hematopoietic differentiation,the efficiency of NK cell generation from hESC,the in vitro effector functions,and the expression of effector function related surface receptors.Compared to the control group,the DH group had a significant increase in the number of arterial hematopoietic endothelial cells(CD34+DLL4+)and a significant decrease in primitive hematopoietic related cells(CD34-CD43+)on day 8 of hematopoietic differentiation(P<0.05).On day 28 of NK cell differentiation,the DH group demonstrated a significant increase in the number of NK cells(CD45+CD56+),while a slight increase in the expression of effector function-related molecules such as IFN-γ,Granzyme B,Perforin and CD107a without statistical significance.Furthermore,the activation receptors CD16a and CD69 were significantly increased,NKP46 was significantly decreased,the inhibitory receptor NKG2A was significantly increased,while CD96 was significantly decreased on hESC-NK cells of DH groups(P<0.05).Conclusively,enhancing the signals for definitive hematopoiesis during hESC differentiation into hematopoietic stem/progenitor cells significantly improves the yield of NK cells and the expression of CD16a without affecting their in vitro effector functions.Our study provides a new approach to improving the efficiency of hESC-NK cell or iPSC-NK cell generation.
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Ischemic dysfunction is an important global health problem. Vascular endothelial cells(VECs) play a key role in angiogenesis, and insufficient vascular remodeling may lead to chronic nonhealing wounds. Therefore, effective VEC generation strategies of exploration help improve angiogenesisin damaged tissues. Embryonic stem cells (ESCs) are widely used in the study of tissueendothelialization, and endothelial progenitor cells (EPCs) are indispensable parts of the development ofVECs. The aims of this study were to find a rapid, easily screened and reproducible method for thederivation of EPCs from mouse embryonic stem cells (mESCs), and obtain VECs with high survival ratesand strong functions from the directed differentiation of the EPCs. The results showed that mESCs weredifferentiated into " stepping stone" -like progenitor cells with active proliferative ability by 10 ng / mLVEGF and 5 ng / mL bFGF. At the same time, the method of differential adherence was helpful for theselection of EPCs, and EPCs induced high expression of CD133 and CD34 (The relative expressionlevels were 0. 88 ± 0. 04 and 2. 12 ± 0. 02, respectively) for 3 days. Then EPCs were digested withacctuse enzymes, and induced to differentiate into vascular endothelial-like cells by 50 ng / mL VEGF and25 ng / mL bFGF for 7 days. The endothelial cells not only expressed endothelial marker genes (CD31, CD144, LAMA5, Tek, KDR and vWF),and marker proteins CD31, CD144 and LAMA5 (The relativeexpression levels were 1. 07 ± 0. 03, 0. 60 ± 0. 02 and 0. 70 ± 0. 02, respectively), but also had thegood ability of migration, tubulogenesis and formation of W-P bodies. Moreover, PBS, EPC and VECwere used to treat wounds of the same size. Both EPC and VEC could accelerate the degree of tissuehealing (The relative healing rates were 78. 93 ± 75. 35%, 95. 57 ± 83. 73% and 100. 00 ± 0. 00%, respectively), and VEC significantly enhanced the ability of wound angiogenesis and inflammatoryresponses. In consequence, this study preliminarily confirmed that mESC-derived EPCs coulddifferentiate into VECs after directional induction for 7 days, which had good function of tissue repair. The physiological pathway on stem cells by stimulating angiogenesis is expected to become a new target fortissue remodeling.
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Objective:To investigate the role of nicotinamide (NIC) in the differentiation of neural crest cells from human embryonic stem cells (hESCs), and lay the foundation for the induction of hESC-derived corneal endothelial cells.Methods:hESCs line H1 cultured for 5-7 days was used for induction.According to the different components of the neural crest induction medium, cells were assigned into different groups for 7-days induction, including group treated without NIC cultured in induction medium only, group treated with NIC cultured in induction medium containing 10 mmol/L NIC, NIC+ resveratrol (Res) group cultured in induction medium containing 10 mmol/L NIC and 10 μmol/L Res and Sirtinol group cultured in induction medium containing 10 μmol/L Sirtinol.Res and Sirtinol were used as SIRT1 activity agonist and inhibitor, respectively.The relative mRNA expression levels of hESCs and neural crest cell markers were detected by real-time fluorescence quantitative PCR at 1, 3, 5 and 7 days during the induction.The expression of neural crest cells markers after 7 days of induction was assayed by immunofluorescence staining.The induction efficiency of NIC and the effect of SIRT1 regulation on human natural killer 1 (HNK-1) positive cells expression were evaluated through flow cytometry analysis of percentages of nerve growth factor receptor (P75) and HNK-1 + cells. Results:Compared with the group treated without NIC, the mRNA expressions of totipotent genes octamer transcription factor 4 (OCT4) and homeodomain proteins (NANOG) were significantly decreased, and the mRNA expression levels of neural crest cell markers P75, HNK-1, SRY-related HMG box (SOX) 9 and SOX10 were significantly increased in the group treated with NIC after 5 days of induction (all at P<0.05). In the group treated without NIC, P75 was weakly expressed, and HNK-1 was sporadically expressed, and transcription factor AP-2β (AP-2β) and paired-like homeodomain transcription factor 2 (PITX2) were not detected.In the group treated with NIC, P75, HNK-1, AP-2β and PITX2 were strongly expressed.The proportion of P75 + HNK-1 + cells and P75 + cells were both significantly higher in the group treated with NIC than without NIC ( t=8.481, P=0.001; t=2.987, P=0.041). The percentage of HNK-1 + cells in groups treated without and with NIC, NIC+ Res group and Sirtinol group were (34.267±12.522)%, (89.633±1.358)%, (64.667±6.429)% and (86.300±3.460)%, respectively, with a statistically significant overall difference ( F=36.799, P<0.001). The proportion of HNK-1 + cells in NIC+ Res group was significantly lower than that in the groups treated with NIC and Sirtinol (all at P<0.05). Conclusions:NIC promotes the differentiation of hESCs-derived neural crest cells by inhibiting the activity of SIRT1 to enhance the expression of HNK-1.NIC treatment may provide a new strategy for source of seed cells in the treatment of neural crest cell-related diseases, such as corneal endothelial transplantation.
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Parthenogenetic embryos, created by activation and diploidization of oocytes, arrest at mid-gestation for defective paternal imprints, which impair placental development. Also, viable offspring has not been obtained without genetic manipulation from parthenogenetic embryonic stem cells (pESCs) derived from parthenogenetic embryos, presumably attributable to their aberrant imprinting. We show that an unlimited number of oocytes can be derived from pESCs and produce healthy offspring. Moreover, normal expression of imprinted genes is found in the germ cells and the mice. pESCs exhibited imprinting consistent with exclusively maternal lineage, and higher X-chromosome activation compared to female ESCs derived from the same mouse genetic background. pESCs differentiated into primordial germ cell-like cells (PGCLCs) and formed oocytes following in vivo transplantation into kidney capsule that produced fertile pups and reconstituted ovarian endocrine function. The transcriptome and methylation of imprinted and X-linked genes in pESC-PGCLCs closely resembled those of in vivo produced PGCs, consistent with efficient reprogramming of methylation and genomic imprinting. These results demonstrate that amplification of germ cells through parthenogenesis faithfully maintains maternal imprinting, offering a promising route for deriving functional oocytes and having potential in rebuilding ovarian endocrine function.
Subject(s)
Animals , Female , Mice , Mice, Transgenic , Mouse Embryonic Stem Cells/metabolism , Oocytes/metabolism , ParthenogenesisABSTRACT
Differentiated cells can be reprogrammed into induced pluripotent stem cells (iPSCs) by overexpressing defined transcription factors. The process of reprogramming requires the interaction of various transcription factors to regulate the transformation of cell fate. Hoxd12 (Homeobox D12) is one of the transcription factors regulating the embryonic development of vertebrates, and it plays an outstanding role in the development of the limb, body axis formation, and cell signal transduction. However, any roles of Hoxd12 may play in the somatic cell reprogramming and the pluripotency of embryonic stem cells (ESCs) have not been reported. In this study, we firstly used 7 factors (Sall4-Esrrb-Jdp2-Glis1-Mkk6-Nanog-Kdm2b) and Yamanaka factors (Oct4-Klf4-Sox2) as the research model, combined with RNA interference (shRNA) and gene overexpression, to explore the mechanism of Hoxd12 in somatic cell reprogramming. Moreover, we used CRISPR/Cas9 gene editing to construct Hoxd12 knockout embryonic stem cell lines, and combined embryoid body formation (EB) and RNA sequencing (RNA-seq) to explore the function of Hoxd12 in the pluripotency of ESCs. The conclusions are as follows: (1) Knocking down of Hoxd12 inhibits 7 factor-induced reprogramming (
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Embryonic stem cells (ESCs) have the ability to differentiate into various adult cells, and their fate in the process of development and differentiation is determined by the comprehensive regulation of multiple factors such as gene expression, epigenetics, and extracellular signals. Epigenetic regulation, such as DNA methylation, histone acetylation, and methylation, plays an important role in the maintenance of pluripotency and differentiation of ESCs. Suds3 (Sin3 histone deacetylase corepressor complex component SDS3) is one of the important components of Sin3 histone deacetylase complex. It played an important role in embryonic development, cell proliferation, chromosome separation and other biological processes. However, the functions of Suds3 in ESCs, such as its influence on the proliferation, maintenance of pluripotency and differentiation of ESCs, were rarely reported. In this study, we used CRISPR/Cas9 gene editing technology to construct a Suds3 knockout mouse embryonic stem cell line, and combined cell culture, in vitro embryoid body (EB) formation and in vivo teratoma formation, CCK-8 and cell counting experiments to study the function of Suds3 in ESCs. Western blotting results showed that the SUDS3 protein was not expressed, and the Suds3 gene was successfully knocked out. Through the observation of cell morphology and fluorescence quantitative PCR (QRT-PCR) to detect the expression of pluripotency genes, we found that the knockout of Suds3 had no significant effect on the maintenance of pluripotency of ESCs. Embryoid body (EB) formation experiments revealed that on the fourth and sixth days of EB formation, the pluripotency gene expression was not down-regulated as quickly as WT cells but increased in Suds3
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ABSTRACT Degenerative retinal diseases such as retinitis pigmentosa, Stargardt's macular dystrophy, and age-related macular degeneration are characterized by irreversible loss of vision due to direct or indirect photoreceptor damage. No effective treatments exist, but stem cell studies have shown promising results. Our aim with this review was to describe the types of stem cells that are under study, their effects, and the main clinical trials involving them.
RESUMO As doenças degenerativas da retina, como retinose pigmentar, distrofia macular de Stargardt e degeneração macular relaciona à idade, são caracterizadas por perda irre versível da visão devido a danos diretos ou indiretos aos fotorreceptores. Não existem tratamentos eficazes, porém os estudos com células-tronco mostraram resultados promissores. Nosso objetivo com esta revisão foi descrever os tipos de células-tronco em estudo, seus efeitos e os principais ensaios clínicos que as envolvem.
Subject(s)
Humans , Retinal Degeneration/therapy , Pluripotent Stem Cells/transplantation , Stem Cell Transplantation/methods , Retina/cytology , Clinical Trials as Topic , Treatment OutcomeABSTRACT
Objective To explore the effect of concave and convex interface on in vitro culture of mouse embryonic stem cells. Methods Mouse embryonic stem cells were cultured on substrate with concave and convex interface. The biological morphology of cell colony was observed. The pluripotency of embryonic stem cells was detected by immunofluorescence and alkaline phosphatase (ALP) staining. Results Embryonic stem cells on concave substrates and convex substrates had higher stereo degree and circularity than those on flat substrates, but it was more obvious on concave substrates. Besides, the expression level of Oct4-GFP and the staining intensity of ALP in embryonic stem cells which were cultured on concave substrates and convex substrates were significantly higher than those on flat basement, especially on concave substrates. Conclusion sCompared with flat substrates, concave substrates and convex substrates had positive effects on the pluripotency maintenance of embryonic stem cells, which could help to maintain pluripotency, but concave substrates had better effects. Changing the substrate curvature could help to maintain pluripotency of embryonic stem cells cultured in vitro. The research findings are of great significance to the study and clinical application of embryonic stem cells.
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Dysregulation of circadian rhythms associates with cardiovascular disorders. It is known that deletion of the core circadian gene Bmal1 in mice causes dilated cardiomyopathy. However, the biological rhythm regulation system in mouse is very different from that of humans. Whether BMAL1 plays a role in regulating human heart function remains unclear. Here we generated a BMAL1 knockout human embryonic stem cell (hESC) model and further derived human BMAL1 deficient cardiomyocytes. We show that BMAL1 deficient hESC-derived cardiomyocytes exhibited typical phenotypes of dilated cardiomyopathy including attenuated contractility, calcium dysregulation, and disorganized myofilaments. In addition, mitochondrial fission and mitophagy were suppressed in BMAL1 deficient hESC-cardiomyocytes, which resulted in significantly attenuated mitochondrial oxidative phosphorylation and compromised cardiomyocyte function. We also found that BMAL1 binds to the E-box element in the promoter region of BNIP3 gene and specifically controls BNIP3 protein expression. BMAL1 knockout directly reduced BNIP3 protein level, causing compromised mitophagy and mitochondria dysfunction and thereby leading to compromised cardiomyocyte function. Our data indicated that the core circadian gene BMAL1 is critical for normal mitochondria activities and cardiac function. Circadian rhythm disruption may directly link to compromised heart function and dilated cardiomyopathy in humans.
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Dysregulation of circadian rhythms associates with cardiovascular disorders. It is known that deletion of the core circadian gene Bmal1 in mice causes dilated cardiomyopathy. However, the biological rhythm regulation system in mouse is very different from that of humans. Whether BMAL1 plays a role in regulating human heart function remains unclear. Here we generated a BMAL1 knockout human embryonic stem cell (hESC) model and further derived human BMAL1 deficient cardiomyocytes. We show that BMAL1 deficient hESC-derived cardiomyocytes exhibited typical phenotypes of dilated cardiomyopathy including attenuated contractility, calcium dysregulation, and disorganized myofilaments. In addition, mitochondrial fission and mitophagy were suppressed in BMAL1 deficient hESC-cardiomyocytes, which resulted in significantly attenuated mitochondrial oxidative phosphorylation and compromised cardiomyocyte function. We also found that BMAL1 binds to the E-box element in the promoter region of BNIP3 gene and specifically controls BNIP3 protein expression. BMAL1 knockout directly reduced BNIP3 protein level, causing compromised mitophagy and mitochondria dysfunction and thereby leading to compromised cardiomyocyte function. Our data indicated that the core circadian gene BMAL1 is critical for normal mitochondria activities and cardiac function. Circadian rhythm disruption may directly link to compromised heart function and dilated cardiomyopathy in humans.
ABSTRACT
Dysregulation of circadian rhythms associates with cardiovascular disorders. It is known that deletion of the core circadian gene Bmal1 in mice causes dilated cardiomyopathy. However, the biological rhythm regulation system in mouse is very different from that of humans. Whether BMAL1 plays a role in regulating human heart function remains unclear. Here we generated a BMAL1 knockout human embryonic stem cell (hESC) model and further derived human BMAL1 deficient cardiomyocytes. We show that BMAL1 deficient hESC-derived cardiomyocytes exhibited typical phenotypes of dilated cardiomyopathy including attenuated contractility, calcium dysregulation, and disorganized myofilaments. In addition, mitochondrial fission and mitophagy were suppressed in BMAL1 deficient hESC-cardiomyocytes, which resulted in significantly attenuated mitochondrial oxidative phosphorylation and compromised cardiomyocyte function. We also found that BMAL1 binds to the E-box element in the promoter region of BNIP3 gene and specifically controls BNIP3 protein expression. BMAL1 knockout directly reduced BNIP3 protein level, causing compromised mitophagy and mitochondria dysfunction and thereby leading to compromised cardiomyocyte function. Our data indicated that the core circadian gene BMAL1 is critical for normal mitochondria activities and cardiac function. Circadian rhythm disruption may directly link to compromised heart function and dilated cardiomyopathy in humans.
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@#Retinal degenerative disease can lead to decreased vision, which is a blinding ophthalmopathy caused by irreversible damage or apoptosis of retinal pigment epithelium(RPE)cells or photoreceptor cells, often resulting in visual impairment or even blindness. Human embryonic stem cells(hESCs)are a kind of multi-directional differentiation cells. By appropriate methods, hESCs can be differentiated into various retinal cells. Since human PRE cells cannot be regenerated, studies have shown that the clinical treatment of retinopathy with stem cell derived RPE cell transplantation has practical prospects and has made a breakthrough in recent years. Due to the limitations of multiple factors, the selection of methods and the complexity of induction conditions, the efficiency of induced differentiation of RPE and the survival rate after transplantation vary greatly and are unstable. Therefore, the current researches should focus on how to integrate different culture methods, take advantages and eliminate disadvantages, so as to improve the directed differentiation efficiency of hESCs, as well as the number and quality of induced cells, thus reducing culture pollution and immune rejection and so on. Here, we will summarize the current examples of various culture methods and give a review from different perspectives.
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BACKGROUND: Autoimmune diseases are a class of diseases that cause a strong immune response to the continuous lack of self-tissue-specific antigens in the thymus. Hypothyroidism and unstable expression of tissue-specific antigens in the thymus can limit the therapeutic effect. The thymus is mainly composed of thymic epithelial cells, but the limited number of mature thymic epithelial cells and thymic epithelial progenitor cells in the thymus has greatly limited related research. OBJECTIVE: To detect the expression of autoimmune regulator (AIRE) when mouse embryonic stem cells were transformed into thymic epithelial progenitor cells. METHODS: A two-step differentiation method was used to induce the differentiation of mouse embryonic stem cells into endoderm and then into thymic epithelial progenitor cells. The cells were collected at 0, 3, and 13 days of induced differentiation. Immunofluorescence, flow cytometry, western blot and real-time PCR were used to detect the expression of cell-associated genes and proteins. RESULTS AND CONCLUSION: Positive expression of OCT4 and SSEA1 was detected by immunofluorescence at 0 day of induction. The double positive expression of SOX17 and FoxA2 was measured by immunofluorescence at 3 days of induction. The positive expression of EpCAM, K5 and K8 were analyzed by flow cytometry at 13 days of induction. During the directional differentiation of mouse embryonic stem cells, real-time PCR indicated that the expression of PAX1, PAX9, FOXN1 and PLET1 showed an increasing trend. The expression of AIRE gene increased significantly at 0, 3, and 13 days of induction. At the same time, the expression of INS2 gene and GAD67 gene also increased. Western blot assay showed that the expression of AIRE protein gradually decreased at 0, 3, and 13 days of induction; however, insulin protein and GAD67 protein were not detected. Overall findings indicate that mouse embryonic stem cells can successfully differentiate into thymic epithelial progenitor cells with highly expressed AIRE gene, which promotes the expression of INS2 and GAD67 genes, and provides an evaluation basis for cell transplantation in the treatment of autoimmune diseases.
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BACKGROUND: Exosomes contain DNA fragments, mRNA, miRNA, functional proteins, transcription factors and other substances with biological activities. Their membrane structure also expresses a variety of antigens and antibody molecules, thus producing various biological effects. Recent studies have shown that it has similar therapeutic effects with stem cell transplantation and can be used as a substitute of stem cell transplantation in the treatment of cardiovascular diseases. OBJECTIVE: To summarize the application of exosomes from different stem cells in the treatment of cardiovascular diseases, so as to provide reference and basis for exosomes applied in the treatment of cardiovascular diseases. METHODS: Articles in PubMed database from 2005 to 2019 were searched using the search terms of “exosomes, cardiovascular diseases, embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells.” Articles in databases of CNKI and VIP from 2014 to 2019 were retrieved with the search terms of “exosome, cardiovascular disease, embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells.” The literature and references were reviewed one by one. RESULTS AND CONCLUSION: Exosomes derived from stem cells are safer and more effective than stem cell transplantation, and have great potential in the prevention and treatment of cardiovascular diseases. However, the research on the function and use of exosomes is still in its infancy. In addition, low exosome content and cumbersome extraction process limit its clinical application.
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BACKGROUND: In the research of human embryonic stem cells, introducing exogenous molecules such as DNA into cells is a common research method, but the transfection efficiency is relatively low. It is crucial to answer the question of how to optimize the existing conditions to improve the transfection efficiency. OBJECTIVE: To compare the effects of two different passaging methods on H9 transfection efficiency, in order to optimize the conditions required for embryonic stem cell transfection. METHODS: Human embryonic stem cell lines H9 were cultured for 48 hours after small clone passaging or single-cell passaging. Lipofectamine 3000 was used to transfect pAdTrack-AKT1 fluorescent plasmid into human embryonic stem cells. After 2 days of transfection, the expression of fluorescent plasmids was observed by fluorescence microscope and the transfection efficiency was detected by flow cytometry. RT-qPCR and western blot were used to detect the mRNA and protein expression levels of AKT1 respectively. RESULTS AND CONCLUSION: Under the fluorescence microscopy, the number of cells expressing fluorescent plasmids in the single-cell passaging group was more than that in the small clone passaging group, and the flow cytometry analysis showed that the transfection efficiency of cells in the single-cell passaging group was (47.18±2.00)%, which was significantly higher than (19.52±0.86)% in the small clone passaging group (P < 0.01). RT-qPCR and western blot analysis showed that the expression levels of AKT1 mRNA and protein in the single-cell passaging group were significantly higher than those in the small clone passaging group (P < 0.01). These findings indicate that single-cell passaging can increase the contact area between cells and transfection reagent liposomes, and improve the transfection efficiency of human embryonic stem cells.
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BACKGROUND: The characteristics of laminin that can promote the proliferation of stem cells have been widely concerned. OBJECTIVE: To review the interactions between laminin and many different stem cells, and provide reliable theoretical basis for chondrogenic research and application of stem cells. METHODS: Wanfang, CNKI, PubMed and Web of Science databases were searched for articles related to mechanism of laminin, changes in stem cell behaviors, and cartilage regeneration published from January 2010 to October 2019. The retrieval terms were “laminin” and “steam cells” in Chinese and English. Duplicated and poorly related articles were excluded, and finally 57 articles were included for review. RESULTS AND CONCLUSION: (1) The structural characteristics of laminin were summarized. The spatiotemporal changes of laminin during cartilage development and degradation were analyzed. At the same time, the distribution of laminin expression in natural cartilage tissue and tissue engineered cartilage tissue was compared. (2) The effects of laminin on the proliferation of various stem cells, including embryonic stem cells, induced pluripotent stem cells and adult stem cells, were described. (3) The possible hotspots on the combination of laminin and stem cells for cartilage regeneration were proposed, with the attempt of providing theoretical basis for cartilage repair and regeneration in the future.
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Objective To construct human embryonic stem cell (hESC) line with forkhead box G1 (FOXG1) gene knockout by clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) gene editing technology, and to investigate the role of FOXG1 gene in the early neural induction of hESCs. Methods Two guide RNAs (gRNAs) were transfected to induce FOXG1 gene large fragment knockout in hESCs by CRISPR/Cas9 gene editing technology. FOXG1 gene knockout hESCs were confirmed by monoclonal screening, sequencing and Western blotting analysis. The expression of the key markers including paired box 6 (PAX6), sex-determining region Y-box 2 (SOX2) and orthodenticle homeobox 2 (OTX2) was detected by immunofluorescence staining and qRT-PCR in the early process of neural induction before and after FOXG1 gene knockout. Results hESCs with FOXG1 gene large fragment knockout were successfully obtained by CRISPR/Cas9 gene editing technology. The results of immunofluorescence staining and qRTPCR suggested that FOXG1 deletion did not significantly influence the expression of PAX6, SOX2 and OTX2 during neural induction. Conclusion FOXG1 gene large fragment knockout in hESCs can be quickly induced by a pair of gRNAs cotransfection. FOXG1 deletion has no significant impacts on neural induction of hESCs.
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Previously, the majority of human embryonic stem cells and human induced pluripotent stem cells have been derived on feeder layers and chemically undefined medium. Those media components related to feeder cells, or animal products, often greatly affect the consistency of the cell culture. There are clear advantages of a defined, xeno-free, and feeder-free culture system for human pluripotent stem cells (hPSCs) cultures, since consistency in the formulations prevents lot-to-lot variability. Eliminating all non-human components reduces health risks for downstream applications, and those environments reduce potential immunological reactions from stem cells. Therefore, development of feeder-free hPSCs culture systems has been an important focus of hPSCs research. Recently, researchers have established a variety of culture systems in a defined combination, xeno-free matrix and medium that supports the growth and differentiation of hPSCs. Here we described detailed hPSCs culture methods under feeder-free and chemically defined conditions using vitronetin and TeSR-E8 medium including supplement bioactive lysophospholipid for promoting hPSCs proliferation and maintaining stemness.