BACKGROUND Embryonic stem cells(ESCs)serve as a crucial ex vivo model,representing epiblast cells derived from the inner cell mass of blastocyst-stage embryos.ESCs exhibit a unique combination of self-renewal potency,...BACKGROUND Embryonic stem cells(ESCs)serve as a crucial ex vivo model,representing epiblast cells derived from the inner cell mass of blastocyst-stage embryos.ESCs exhibit a unique combination of self-renewal potency,unlimited proliferation,and pluripotency.The latter is evident by the ability of the isolated cells to differ-entiate spontaneously into multiple cell lineages,representing the three primary embryonic germ layers.Multiple regulatory networks guide ESCs,directing their self-renewal and lineage-specific differentiation.Apoptosis,or programmed cell death,emerges as a key event involved in sculpting and forming various organs and structures ensuring proper embryonic development.How-ever,the molecular mechanisms underlying the dynamic interplay between diffe-rentiation and apoptosis remain poorly understood.AIM To investigate the regulatory impact of apoptosis on the early differentiation of ESCs into cardiac cells,using mouse ESC(mESC)models-mESC-B-cell lym-phoma 2(BCL-2),mESC-PIM-2,and mESC-metallothionein-1(MET-1)-which overexpress the anti-apoptotic genes Bcl-2,Pim-2,and Met-1,respectively.METHODS mESC-T2(wild-type),mESC-BCL-2,mESC-PIM-2,and mESC-MET-1 have been used to assess the effect of potentiated apoptotic signals on cardiac differentiation.The hanging drop method was adopted to generate embryoid bodies(EBs)and induce terminal differentiation of mESCs.The size of the generated EBs was measured in each condition compared to the wild type.At the functional level,the percentage of cardiac differentiation was measured by calculating the number of beating cardiomyocytes in the manipulated mESCs compared to the control.At the molecular level,quantitative reverse transcription-polymerase chain reaction was used to assess the mRNA expression of three cardiac markers:Troponin T,GATA4,and NKX2.5.Additionally,troponin T protein expression was evaluated through immunofluorescence and western blot assays.RESULTS Our findings showed that the upregulation of Bcl-2,Pim-2,and Met-1 genes led to a reduction in the size of the EBs derived from the manipulated mESCs,in comparison with their wild-type counterpart.Additionally,a decrease in the count of beating cardiomyocytes among differentiated cells was observed.Furthermore,the mRNA expression of three cardiac markers-troponin T,GATA4,and NKX2.5-was diminished in mESCs overexpressing the three anti-apoptotic genes compared to the control cell line.Moreover,the overexpression of the anti-apoptotic genes resulted in a reduction in troponin T protein expression.CONCLUSION Our findings revealed that the upregulation of Bcl-2,Pim-2,and Met-1 genes altered cardiac differentiation,providing insight into the intricate interplay between apoptosis and ESC fate determination.展开更多
Background The induced pluripotent stem cell （iPSC） has shown great potential in cellular therapy of myocardial infarction （MI）, while its application is hampered by the low efficiency of cardiomyocyte differentia...Background The induced pluripotent stem cell （iPSC） has shown great potential in cellular therapy of myocardial infarction （MI）, while its application is hampered by the low efficiency of cardiomyocyte differentiation. The present study was designed to investigate the effects of cardiotrophin-1 （CT-1） on cardiomyocyte differentiation from mouse induced pluripotent stem cells （miPSCs） and the underlying mechanisms involved. Methods The optimal treatment condition for cardiomyocyte differentiation from miPSCs was established with ideal concentration （10 ng/mL） and duration （from day 3 to day 14） of CT-1 administration. Up-regulated expression of cardiac specific genes that accounted for embryonic cardiogenesis was observed by quantitative RT-PCR. Elevated amount of a-myosin heavy chain （ct-MHC） and cardiac troponin I （cTn I） positive cells were detected by immunofluorescence staining and flow cytometry analysis in CT- 1 group. Results Transmission electron microscopic analysis revealed that cells treated with CT- 1 showed better organized sacromeric structure and more mitochondria, which are morphological characteristic of matured cardiomyocytes. Western blot demonstrated that CT-1 promotes cardiomyocyte differentiation from miPSCs partly via JAK2/STAT3/Pim-1 pathway as compared with control group. Conclusions These findings suggested that CT-1 could enhance the cardiomyocyte differentiation as well as the maturation of mouse induced pluripotent stem cell derived cardiomyocytes by regulating JAK2/STAT3/Pim-1 signaling pathway.展开更多
Objective：To investigate the effect of MCP-1 on mesenchymal stem cells（MSCs） homing to injured myocardium in a rat myocardial infarction（MI） model. Methods：Rat myocardial infarction model was established by perm...Objective：To investigate the effect of MCP-1 on mesenchymal stem cells（MSCs） homing to injured myocardium in a rat myocardial infarction（MI） model. Methods：Rat myocardial infarction model was established by permanent left anterior descending branch ligation. Mesenchymal stem cells from donor rats were cultured in IMDM and labeled with BrdU. The Rats were divided into two groups. Monocyte chemotactic protein I（MCP-1） expression were measured by in situ hybridization and immunohistochemistry in the sham operated or infarcted hearts at 1, 2, 4, 7, 14 and 28 days post operation in MCP-1 detection group. The rats were injected with MCP-1, anti-MCP-1 antibody or saline 4 days after myocardial infarction in intervention group. Then, a total of 5 × 10^6 cells in 2.5 ml of PBS were injected through the tail vein. The number of the labeled MSCs in the infarcted hearts was counted 3 days post injection. Cardiac function and blood vessel density were assessed 28 days post injection. Results：Self-generating MCP-1 expression was increased at the first day, peaked at the 7^th day and decreased thereafter post MI and remained unchanged in sham operated hearts. The MSCs enrichment in the host hearts were more abundant in the MI groups than that in the non-MI group（P= 0.000）, the MSCs enrichment in the host hearts were more abundant in the MCP-1 injected group than that in the anti-MCP-1 antibody and saline injected groups （P = 0.000）. Cardiac function was improved more in MCP-1 injected group than anti-MCP-1 antibody and saline injected groups（P= 0.000）. Neovascularization in MCP-1 injected group significantly increased compared with that of other groups（P = 0.000）. Conclusion： Myocardial MCP-1 expression was increased only in the early phase post MI. MCP-1 may enhance MSCs homing to the injured heart and improve cardiac function by promoting neovascularization.展开更多
Cell therapy has shown beneficial effects on ventricular function and tissue regeneration in patients with acute and chronic myocardial infarction, although with diverse grades of variability in the results, possibly ...Cell therapy has shown beneficial effects on ventricular function and tissue regeneration in patients with acute and chronic myocardial infarction, although with diverse grades of variability in the results, possibly by proportion, subtype and cell cycle status. Objective: Identify and phenotypically characterize, via CXCR4 and SDF-1 expression, the bone marrow cell subpopulations that are mobilized into the bloodstream in patients with Acute Myocardial Infarction (AMI) and Acute Ischemia (AI) such as acute angina and Chronic Ischemia (CI) such as chronic stable angina, and also determine the cell cycle status of these cells. Method: Patients with AMI and AI were recruited in the ICCU, and patients with CI in the departments of cardiology and cardiovascular surgery. The quantification of cellular subpopulations was made by cytofluorometry with a FACS caliburcyto fluorometry (Becton Dickinson) with specific FITC-labeled anti human monoclonal antibodies against CD34, CD133, CD117, CD48, CXCR4, SDF-1 and Ki67 (Becton Dickinson). Serum concentration of IL-6 and IL-8 were determined by a sequential solid phase chemiluminescent assay performed in a SIEMENS IMMULITE 1000 Analyzer. Statistical analysis was made with the SPSS version 20.0 for Windows. A p value 3/ml) than that in AI (9.2 ± 1.3 × 103/ml) and CI (6.6 ± 1.1 × 103/ml) patients (p p = 0.22 to 0.39), but interestingly in AMI and AI patients, cells were CXCR4+ in almost half of these mobilized cells, although the proportion was significantly higher in AMI patients (46.8% ± 7.1% to 55.7% ± 6.3% vs 23% ± 1.6% to 28.4% ± 2.1%, p = 0.03 to 0.05). A similar behavior was observed with the Ki67 antibody (29.9% ± 2.1% to 36.1% ± 6.3% vs 10% ± 1.2% to 24% ± 1.1%, p = 0.001 to 0.05). Bivariate analysis of the results showed a significant correlation of the cell proportion in AMI but not in AI and CI patients (p = 0.001 to 0.05;0.12 to 0.87 and 0.17 to 0.92 respectively). The amount of myocardial tissue infarcted did not show any correlation with the amount of cellular subpopulations mobilized to peripheral blood (r = 0.10 to 0.20;p = 0.21 to 0.64) from the bone marrow. Conclusion: The proportion of cellular subpopulations with regenerative potential mobilized to circulation during an event of Acute Myocardial Infarction is significantly higher than during an event of acute angina and chronic stable angina, with a significant proportion of mobilized cells that expressed CXCR4, most of which were already in some of the cell cycle phases.展开更多
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 i...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 1α(HIF-1α) expression and physical hypoxia(5% O_2) treatment could induce Jagged1 expression in neonatal rat CMs. Pharmacological inhibition of HIF-1α by YC-1 attenuated hypoxia-promoted Jagged1 expression in CMs. An ERK inhibitor(PD98059), but not inhibitors of JNK(SP600125), Notch(DAPT), NF-κB(PTDC), JAK(AG490), or STAT3(Stattic) suppressed hypoxiainduced Jagged1 protein expression in CMs. c-Kit^+ CSCs isolated from neonatal rat hearts using a magnetic-activated cell sorting method expressed GATA4, SM22α 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 via HIF-1α/Jagged1/Notch signaling.展开更多
Small-diameter vascular grafts fabricated from synthetic biodegradable polymers exhibit beneficial mechanical properties but often face poor regenerative potential.Different tissue engineering approaches have been emp...Small-diameter vascular grafts fabricated from synthetic biodegradable polymers exhibit beneficial mechanical properties but often face poor regenerative potential.Different tissue engineering approaches have been employed to improve tissue regeneration in vascular grafts,but there remains a requirement for a new generation of synthetic grafts that can orchestrate the host response to achieve robust vascular regeneration.Vascular stem/progenitor cells(SPCs)are mostly found in quiescent niches but can be activated in response to injury and participate in endothelium and smooth muscle regeneration during neo-artery formation.Here,we developed a functional vascular graft by surface immobilization of stem cell antigen-1(Sca-1)antibody on an electrospun poly(ε-caprolactone)graft(PCL-Sca-1 Ab).PCL-Sca-1 Ab promoted capture and retainment of Sca-1+SPCs in vitro.In rat abdominal aorta replacement models,PCL-Sca-1 Ab stimulated in vivo recruitment of Sca-1+SPCs,and drove SPCs differentiation towards vascular cell lineages.The origin of infiltrated Sca-1+SPCs was further investigated using a bone marrow transplantation mouse model,which revealed that Sca-1+SPCs originating from the resident tissues and bone marrow contributed to rapid vascular regeneration of vascular grafts.Our data indicated that PCL-Sca-1 Ab vascular grafts may serve as a useful strategy to develop next generation cell-free vascular grafts.展开更多
基金Supported by the National Council for Scientific Research in Lebanon,CNRS-L.
文摘BACKGROUND Embryonic stem cells(ESCs)serve as a crucial ex vivo model,representing epiblast cells derived from the inner cell mass of blastocyst-stage embryos.ESCs exhibit a unique combination of self-renewal potency,unlimited proliferation,and pluripotency.The latter is evident by the ability of the isolated cells to differ-entiate spontaneously into multiple cell lineages,representing the three primary embryonic germ layers.Multiple regulatory networks guide ESCs,directing their self-renewal and lineage-specific differentiation.Apoptosis,or programmed cell death,emerges as a key event involved in sculpting and forming various organs and structures ensuring proper embryonic development.How-ever,the molecular mechanisms underlying the dynamic interplay between diffe-rentiation and apoptosis remain poorly understood.AIM To investigate the regulatory impact of apoptosis on the early differentiation of ESCs into cardiac cells,using mouse ESC(mESC)models-mESC-B-cell lym-phoma 2(BCL-2),mESC-PIM-2,and mESC-metallothionein-1(MET-1)-which overexpress the anti-apoptotic genes Bcl-2,Pim-2,and Met-1,respectively.METHODS mESC-T2(wild-type),mESC-BCL-2,mESC-PIM-2,and mESC-MET-1 have been used to assess the effect of potentiated apoptotic signals on cardiac differentiation.The hanging drop method was adopted to generate embryoid bodies(EBs)and induce terminal differentiation of mESCs.The size of the generated EBs was measured in each condition compared to the wild type.At the functional level,the percentage of cardiac differentiation was measured by calculating the number of beating cardiomyocytes in the manipulated mESCs compared to the control.At the molecular level,quantitative reverse transcription-polymerase chain reaction was used to assess the mRNA expression of three cardiac markers:Troponin T,GATA4,and NKX2.5.Additionally,troponin T protein expression was evaluated through immunofluorescence and western blot assays.RESULTS Our findings showed that the upregulation of Bcl-2,Pim-2,and Met-1 genes led to a reduction in the size of the EBs derived from the manipulated mESCs,in comparison with their wild-type counterpart.Additionally,a decrease in the count of beating cardiomyocytes among differentiated cells was observed.Furthermore,the mRNA expression of three cardiac markers-troponin T,GATA4,and NKX2.5-was diminished in mESCs overexpressing the three anti-apoptotic genes compared to the control cell line.Moreover,the overexpression of the anti-apoptotic genes resulted in a reduction in troponin T protein expression.CONCLUSION Our findings revealed that the upregulation of Bcl-2,Pim-2,and Met-1 genes altered cardiac differentiation,providing insight into the intricate interplay between apoptosis and ESC fate determination.
基金This work was supported by the National Funds for Distinguished Young Scientists of China （No. 81325009） and National Nature Science Foundation of China （No. 81270168, No. 81227901）, （Feng Cao BWS12J037）, Innovation Team granted by Ministry of Education PRC （IRT1053）, National Basic Research Program of China （2012CB518101）. Shaanxi Province Program （2013K12-02-03, 2014KCT-20）. The authors declare no conflict of interest.
文摘Background The induced pluripotent stem cell （iPSC） has shown great potential in cellular therapy of myocardial infarction （MI）, while its application is hampered by the low efficiency of cardiomyocyte differentiation. The present study was designed to investigate the effects of cardiotrophin-1 （CT-1） on cardiomyocyte differentiation from mouse induced pluripotent stem cells （miPSCs） and the underlying mechanisms involved. Methods The optimal treatment condition for cardiomyocyte differentiation from miPSCs was established with ideal concentration （10 ng/mL） and duration （from day 3 to day 14） of CT-1 administration. Up-regulated expression of cardiac specific genes that accounted for embryonic cardiogenesis was observed by quantitative RT-PCR. Elevated amount of a-myosin heavy chain （ct-MHC） and cardiac troponin I （cTn I） positive cells were detected by immunofluorescence staining and flow cytometry analysis in CT- 1 group. Results Transmission electron microscopic analysis revealed that cells treated with CT- 1 showed better organized sacromeric structure and more mitochondria, which are morphological characteristic of matured cardiomyocytes. Western blot demonstrated that CT-1 promotes cardiomyocyte differentiation from miPSCs partly via JAK2/STAT3/Pim-1 pathway as compared with control group. Conclusions These findings suggested that CT-1 could enhance the cardiomyocyte differentiation as well as the maturation of mouse induced pluripotent stem cell derived cardiomyocytes by regulating JAK2/STAT3/Pim-1 signaling pathway.
文摘Objective：To investigate the effect of MCP-1 on mesenchymal stem cells（MSCs） homing to injured myocardium in a rat myocardial infarction（MI） model. Methods：Rat myocardial infarction model was established by permanent left anterior descending branch ligation. Mesenchymal stem cells from donor rats were cultured in IMDM and labeled with BrdU. The Rats were divided into two groups. Monocyte chemotactic protein I（MCP-1） expression were measured by in situ hybridization and immunohistochemistry in the sham operated or infarcted hearts at 1, 2, 4, 7, 14 and 28 days post operation in MCP-1 detection group. The rats were injected with MCP-1, anti-MCP-1 antibody or saline 4 days after myocardial infarction in intervention group. Then, a total of 5 × 10^6 cells in 2.5 ml of PBS were injected through the tail vein. The number of the labeled MSCs in the infarcted hearts was counted 3 days post injection. Cardiac function and blood vessel density were assessed 28 days post injection. Results：Self-generating MCP-1 expression was increased at the first day, peaked at the 7^th day and decreased thereafter post MI and remained unchanged in sham operated hearts. The MSCs enrichment in the host hearts were more abundant in the MI groups than that in the non-MI group（P= 0.000）, the MSCs enrichment in the host hearts were more abundant in the MCP-1 injected group than that in the anti-MCP-1 antibody and saline injected groups （P = 0.000）. Cardiac function was improved more in MCP-1 injected group than anti-MCP-1 antibody and saline injected groups（P= 0.000）. Neovascularization in MCP-1 injected group significantly increased compared with that of other groups（P = 0.000）. Conclusion： Myocardial MCP-1 expression was increased only in the early phase post MI. MCP-1 may enhance MSCs homing to the injured heart and improve cardiac function by promoting neovascularization.
文摘Cell therapy has shown beneficial effects on ventricular function and tissue regeneration in patients with acute and chronic myocardial infarction, although with diverse grades of variability in the results, possibly by proportion, subtype and cell cycle status. Objective: Identify and phenotypically characterize, via CXCR4 and SDF-1 expression, the bone marrow cell subpopulations that are mobilized into the bloodstream in patients with Acute Myocardial Infarction (AMI) and Acute Ischemia (AI) such as acute angina and Chronic Ischemia (CI) such as chronic stable angina, and also determine the cell cycle status of these cells. Method: Patients with AMI and AI were recruited in the ICCU, and patients with CI in the departments of cardiology and cardiovascular surgery. The quantification of cellular subpopulations was made by cytofluorometry with a FACS caliburcyto fluorometry (Becton Dickinson) with specific FITC-labeled anti human monoclonal antibodies against CD34, CD133, CD117, CD48, CXCR4, SDF-1 and Ki67 (Becton Dickinson). Serum concentration of IL-6 and IL-8 were determined by a sequential solid phase chemiluminescent assay performed in a SIEMENS IMMULITE 1000 Analyzer. Statistical analysis was made with the SPSS version 20.0 for Windows. A p value 3/ml) than that in AI (9.2 ± 1.3 × 103/ml) and CI (6.6 ± 1.1 × 103/ml) patients (p p = 0.22 to 0.39), but interestingly in AMI and AI patients, cells were CXCR4+ in almost half of these mobilized cells, although the proportion was significantly higher in AMI patients (46.8% ± 7.1% to 55.7% ± 6.3% vs 23% ± 1.6% to 28.4% ± 2.1%, p = 0.03 to 0.05). A similar behavior was observed with the Ki67 antibody (29.9% ± 2.1% to 36.1% ± 6.3% vs 10% ± 1.2% to 24% ± 1.1%, p = 0.001 to 0.05). Bivariate analysis of the results showed a significant correlation of the cell proportion in AMI but not in AI and CI patients (p = 0.001 to 0.05;0.12 to 0.87 and 0.17 to 0.92 respectively). The amount of myocardial tissue infarcted did not show any correlation with the amount of cellular subpopulations mobilized to peripheral blood (r = 0.10 to 0.20;p = 0.21 to 0.64) from the bone marrow. Conclusion: The proportion of cellular subpopulations with regenerative potential mobilized to circulation during an event of Acute Myocardial Infarction is significantly higher than during an event of acute angina and chronic stable angina, with a significant proportion of mobilized cells that expressed CXCR4, most of which were already in some of the cell cycle phases.
基金supported by grants from the National Natural Science Foundation of China (Grant Nos.81170121,81460042,81541004 and 81670254)Science and Technology Project of Guangdong Province (2016A020214016)+1 种基金YangFan Plan of Guangdong Province (4YF16007G)Excellent Graduate Student Training Program of Guangdong Medical University (YS2014013)
文摘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 1α(HIF-1α) expression and physical hypoxia(5% O_2) treatment could induce Jagged1 expression in neonatal rat CMs. Pharmacological inhibition of HIF-1α by YC-1 attenuated hypoxia-promoted Jagged1 expression in CMs. An ERK inhibitor(PD98059), but not inhibitors of JNK(SP600125), Notch(DAPT), NF-κB(PTDC), JAK(AG490), or STAT3(Stattic) suppressed hypoxiainduced Jagged1 protein expression in CMs. c-Kit^+ CSCs isolated from neonatal rat hearts using a magnetic-activated cell sorting method expressed GATA4, SM22α 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 via HIF-1α/Jagged1/Notch signaling.
基金supported by grants from the National Natural Science Foundation of China(Nos.81925021,82050410449,81921004 and 81871500)and Science&Technology Project of Tianjin of China(No.18JCJQJC46900).
文摘Small-diameter vascular grafts fabricated from synthetic biodegradable polymers exhibit beneficial mechanical properties but often face poor regenerative potential.Different tissue engineering approaches have been employed to improve tissue regeneration in vascular grafts,but there remains a requirement for a new generation of synthetic grafts that can orchestrate the host response to achieve robust vascular regeneration.Vascular stem/progenitor cells(SPCs)are mostly found in quiescent niches but can be activated in response to injury and participate in endothelium and smooth muscle regeneration during neo-artery formation.Here,we developed a functional vascular graft by surface immobilization of stem cell antigen-1(Sca-1)antibody on an electrospun poly(ε-caprolactone)graft(PCL-Sca-1 Ab).PCL-Sca-1 Ab promoted capture and retainment of Sca-1+SPCs in vitro.In rat abdominal aorta replacement models,PCL-Sca-1 Ab stimulated in vivo recruitment of Sca-1+SPCs,and drove SPCs differentiation towards vascular cell lineages.The origin of infiltrated Sca-1+SPCs was further investigated using a bone marrow transplantation mouse model,which revealed that Sca-1+SPCs originating from the resident tissues and bone marrow contributed to rapid vascular regeneration of vascular grafts.Our data indicated that PCL-Sca-1 Ab vascular grafts may serve as a useful strategy to develop next generation cell-free vascular grafts.
