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Hypoxia is beneficial for the differentiation of stem cells transplanted for myocardial injury, but mechanisms underlying this benefit remain unsolved. Here, we report the impact of hypoxia-induced Jagged1 expression in cardiomyocytes (CMs) for driving the differentiation of cardiac stem cells (CSCs). Forced hypoxia-inducible factor 1 (HIF-1) expression and physical hypoxia (5% O) treatment could induce Jagged1 expression in neonatal rat CMs. Pharmacological inhibition of HIF-1 by YC-1 attenuated hypoxia-promoted Jagged1 expression in CMs. An ERK inhibitor (PD98059), but not inhibitors of JNK (SP600125), Notch (DAPT), NF-B (PTDC), JAK (AG490), or STAT3 (Stattic) suppressed hypoxia-induced Jagged1 protein expression in CMs. c-Kit CSCs isolated from neonatal rat hearts using a magnetic-activated cell sorting method expressed GATA4, SM22 or vWF, but not Nkx2.5 and cTnI. Moreover, 87.3% of freshly isolated CSCs displayed Notch1 receptor expression. Direct co-culture of CMs with BrdU-labeled CSCs enhanced CSCs differentiation, as evidenced by an increased number of BrdU/Nkx2.5 cells, while intermittent hypoxia for 21 days promoted co-culture-triggered differentiation of CSCs into CM-like cells. Notably, YC-1 and DAPT attenuated hypoxia-induced differentiation. Our results suggest that hypoxia induces Jagged1 expression in CMs primarily through ERK signaling, and facilitates early cardiac lineage differentiation of CSCs in CM/CSC co-cultures HIF-1/Jagged1/Notch signaling.
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Objective:To explore the effect of differentiation of cardiac stem cells(CSC)mediated by pilose antler polypeptides on the expressions of terminal myocardial differentiation genes atrial natriuretic polypeptide (ANP)and myosin light chain 2v(MLC-2v),and to clarify the mechanism of repairing the damaged myocardium.Methods:The healthy male Wistar rats born 2 d were selected to extract the CSC.The surface marker c-Kit and the purity of CSC were identified by immunofluorescence and flow cytometry.The culture dish was used as the experimental unit and the extracted cells were divided into the following four groups:blank control group(the same amount of buffer was added for induction),5-azacytidine group(induced with 3 μmol·L-15-azacytidine),pilose antler polypeptides group(induced with 800 mg·L-1pilose antler polypeptides)and combined group(induced with 800 mg·L-1pilose antler polypeptides and 3 μmol·L-15-azacytidine);the cells were incubated for 48 h in the condition of 37℃ and 5% CO2.The expression levels of ANP and MLC-2v in supernatant of the cells in various groups were detected by ELISA method.The expression levels of ANP and MLC-2v mRNA in the cells in various groups were detected by RT-PCR method.Results:CSC were prepared with the purity>95%.The results of ELISA showed that the expression levels of ANP and MLC-2v in 5-azacytidine,pilose antler polypeptides and combined groups were significantly increased compared with blank control group(P<0.05).The expression levels of ANP and MLC-2v in combined group were increased compared 5-azacytidine and pilose antler polypeptides groups,but there were no significant differences(P>0.05).The result of RT-PCR showed that the expression levels of ANP and MLC-2v mRNA in 5-azacytidine,pilose antler polypeptides and combined groups were significantly increased compared with blank control group(P<0.05).Conclusion:Pilose antler polypeptides can induce the differentiation of CSC into cardiac cells by promoting the expressions of ANP and MLC-2v,and they can reduce the cytotoxicity induced by 5-azacytidine in some degrees.
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AIM:To explore the effect of microRNA (miR)-21 on proliferation, migration and differentiation abilities of c-Kit+ cardiac stem cells (CSCs). METHODS:c-Kit+ CSCs were cultured and selected by the methods of en-zyme digestion and magnetic bead separation. miR-21 mimics (50 nmol/L) and mimics negative control ( MNC) were transfected into c-Kit+CSCs with Lipofectamine?2000. The cells was divided into 3 groups:control group:c-Kit+ CSCs without any pretreatment; MNC group:the cells were transfected with MNC for 48 h; mimics group:the cells were trans-fected with miR-21 mimics for 48 h. qPCR was used to assess the expression of miR-21 in each group. CCK-8 and EdU as-says were used to determine the cell proliferation. qPCR and immunofluorescence were used to detect the differentiation in each group. Scratch assay was adopted to explore the migration ability of the cells. RESULTS:The expression of c-Kit in the c-Kit+ CSCs were 90.8%, with 0.6% of CD45 and 0.5% of CD34. A significant increase in miR-21 expression was observed when the cells were transfected with miR-21 mimics for 48 h ( P<0.05). CCK-8 and EdU assays showed that miR-21 significantly increased cell proliferation as compared with MNC group and control group (P<0.05). No difference in the expression of Nkx2.5, CD31 and α-SMA at mRNA and protein levels was observed, and no difference of the migra-tion ability in 3 groups of the c-Kit+ CSCs was found. CONCLUSION:Over-expression of miR-21 significantly promotes the proliferation of c-Kit+ CSCs, without any effect on the cell migration and differentiation.
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Objective: To explore the effect of differentiation of cardiac stem cells (CSC) mediated by pilose antler polypeptides on the expressions of terminal myocardial differentiation genes atrial natriuretic polypeptide (ANP) and myosin light chain 2v (MLC-2v), and to clarify the mechanism of repairing the damaged myocardium Methods: The healthy male Wistar rats born 2 d were selected to extract the CSC. The surface marker c-Kit and the purity of CSC were identified by immunofluorescence and flow cytometry. The culture dish was used as the experimental unit and the extracted cells were divided into the following four groups: blank control group (the same amount of buffer was added for induction), 5-azacytidine group (induced with 3 jumol · L-1 5-azacytidine), pilose antler polypeptides group (induced with 800 mg · L-1 pilose antler polypeptides) and combined group (induced with 800 mg · L-1 pilose antler polypeptides and 3 μmol · L-1 5-azacytidine); the cells were incubated for 48 h in the condition of 37°C and 5% CO2. The expression levels of ANP and MLC-2v in supernatant of the cells in various groups were detected by ELISA method. The expression levels of ANP and MLC-2v mRNA in the cells in various groups were detected by RT-PCR method. Results: CSC were prepared with the purity0.05). The result of RT-PCR showed that the expression levels of ANP and MLC-2v mRNA in 5-azacytidine, pilose antler polypeptides and combined groups were significantly increased compared with blank control group (P<0.05). Conclusion: Pilose antler polypeptides can induce the differentiation of CSC into cardiac cells by promoting the expressions of ANP and MLC-2v, and they can reduce the cytotoxicity induced by 5-azacytidine in some degrees.
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No Brasil, como em todo o mundo, as doenças cardiovasculares têm sido uma das principais causas de morte. A alta mortalidade e as poucas alternativas terapêuticas para esta doença têm estimulado a investigação no campo das células estaminais. Recentemente, alguns grupos têm mostrado a presença de células-tronco/progenitoras residentes no coração. Estas poderiam ser cultivadas diretamente a partir de tecidos cardíacos produzindo aglomerados esféricos denominados Cardioesferas estas, contém células proliferativas que dão origem, após o plaqueamento, a uma população heterogênea denominada: células derivadas de cardioesferas (CDCs). O objetivo deste estudo foi isolar, cultivar e caracterizar as CDCs de camundongos da linhagem CD1. Para isto, as células primárias foram isoladas a partir de corações de camundongos adultos da linhagem CD1 após a digestão de pequenos fragmentos do órgão em 420U/ml utilizando colagenase tipo II por 20 minutos 37°C. Nas análises por Citometria de Fluxo (FACS) foram observadas baixa expressão das moléculas de CD19 (0,4%), CD45 (0,5%) e CD90 (4,77%), e alta expressão das moléculas CD73 (71,47%), CD105 (25,1%), CD14 (25,17%). Nos ensaios de imunofluorescência foi possível observar a expressão das proteínas no citoplasma dos cardiomiócitos: vimentina, desmina e alfa actina de músculo liso, além da expressão do filamento intermediário nestina. Ao analisar a expansão celular por population doubling time foi observado que as CDCs duplicaram sua população original em cerca de 1,8 dias. Estes resultados sugerem que as CDCs isoladas a partir de camundongos da linhagem CD1, são células que apresentam características de células mesenquimais, constituindo uma população celular a ser testada nos estudos em terapias celulares. Estes resultados, motiva a estabelecer protocolos mais efetivos a fim de investigar possíveis efeitos parácrinos benéficos, bem como o potencial angiogênico e cardiogênico destas células.
In Brazil, as elsewhere in the world, cardiovascular diseases have been a major cause of death. The high mortality and few therapeutic alternatives for this disease have stimulated research in the field of stem cells. Recently, some groups have shown the presence of stem cells residents at heart. These could be grown directly from tissue cardiac producing spherical agglomerates called cardiospheres these contains proliferating cells that give rise after plating, a heterogeneous population named: cells derived from cardiospheres (CDC). Our goal in this study was to isolate and characterize the cultivar CDC CD1 strain of mice. For this purpose, primary cells were isolated from hearts of adult mice of the CD1 strain after digestion of the organ into small fragments using 420U/ml collagenase type II for 20 minutes 37 ° C. In analysis by Flow Cytometry (FACS) were observed low expression of CD19 molecules (0.4%), CD45 (0.5%) and CD90 (4.77%), and high expression of the molecules CD73 (71.47%), CD105 (25.1%), CD14 (25.17%). In the immunofluorescence assays was possible to observe the expression of the proteins in the cytoplasm of cardiomyocytes: vimentin, desmin and smooth muscle alpha actin, and expression of the intermediate filament nestin. By analyzing the cellular expansion team for Population doubling was observed that the original CDC doubled its population in about 1.8 days. These results suggest that CDCs isolated from CD1 mouse strain to be have characteristics of mesenchymal cells, constituting a potential population studied in cellular therapies, motivating us to establish more effective protocols to investigate possible beneficial paracrine effects and their angiogenic and cardiogenic potential.
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Células Madre , Miocitos Cardíacos , Corazón , RatonesRESUMEN
[Objective] This article mainly discussed the potential of myocardial cellregeneration and the possible mechanisms involved. [Method] To study the mechanism of cardiac regeneration ability HSCs, this review studyed the relationship of the differentiation of cardiac stem cells, hematopoietic stem cells, myocardial cells and myocardial regeneration and the possible mechanisms involved. [Result] Self-renewing, differentiation both in vitro and in vivo of the c-kit positive CSCs had been seen. No matter in physiological condition or after damage, the c-kit positive CSCs had clonality and the potential of multi-directional differentiation. Hematopoietic stem cells can generate cardiomyocytes and coronary blood vessels for human celltherapy. The ability of dedifferentiation cells to maintain and improve the ventricular function of a damaged heart is very limited. [Conclusion] CSCs and HSCs play an important role in reversing chronic ischemic and non-ischemic heart failure.
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Objective To investigate the changes in morphology and senescence-associated markers of the marrow-derived cardiac stem cells (MCSCs) from rats at different ages and to explore the impacts of age on proliferation, survival and differentiation of MCSCs. Methods With single-cell cloning culture, MCSCs were selected from the bone marrow of young, adult and aged male SD rats respectively. Ultrastructural changes of the cells were viewed under a transmission electron microscope.The senescence-associated changes were examined with SA-β-galactosidase staining and reactive oxygen species(ROS) staining. Distribution of cell cycle of MCSCs from different age groups was evaluated with flow cytometric analysis. Rates of the survived and apoptotic cells were determined by Annexin V/PI double-labeled flow cytometric analysis and Hochest33342 staining. Differentiation of the MCSCs toward cardiomyocytes was induced with BMP-2. Expression of cardiac transcription factors and cardiac specific genes of the cells after induction were examined with RT-PCR. CTnT expression of the cells also be examined with immunocytochemistry. Results The nucleus/plasma ratio of the cells from aged rats decrease and there are some myelin bodies in the cells of aged group. With increasing of age, the MCSCs in S+G2/M phase reduce, while β-galactosidase-positive cells and ROS-positive cells increase. Survival rate of the cells from aged rats is lower than that of the cells from young rats. At four week after induction with BMP-2, expression of Nkx2.5, GATA-4, cTnT mRNA and Cx-43 mRNA of the cells of young group increase significantly. In adult and aged group, expression of the cardiac transcription factors and cardiac specific genes is lower than that of the cells in young group. In immunocytochemical staining, cTnT expression of the cells in young group is stronger after induction with BMP-2. As compared with that of the cells in young group, cTnT expression of the cells in aged group is weak after induction. Conclusion With increasing of age, MCSCs show senescent changes, including their abilities of proliferation, survival and differentiation toward cardiomyocytes decrease.