PGC-1α, a potent transcriptional coactivator, is the major regulator of mitochondrial biogenesis and activity in the cardiac muscle. The dysregulation of PGC-la and its target genes has been reported to be associated...PGC-1α, a potent transcriptional coactivator, is the major regulator of mitochondrial biogenesis and activity in the cardiac muscle. The dysregulation of PGC-la and its target genes has been reported to be associated with congenital and acquired heart diseases. By examining myocardium samples from patients with Tetralogy of Fallot, we show here that PGC-1α expression levels are markedly increased in patients compared with healthy controls and positively correlated with the severity of cyanosis. Furthermore, hypoxia significantly induced the expression of PGC-1α and mitochondrial biogenesis in cultured cardiac myocytes. Mechanistic studies suggest that hypoxia-induced PGC-1α expression is regulated through the AMPK signaling pathway. Together, our data indicate that hypoxia can stimulate the expression of PGC-1α and mitochondrial biogenesis in the cardiac myocytes, and this process might provide a potential adaptive mechanism for cardiac myocytes to increase ATP output and minimize hypoxic damage to the heart.展开更多
Objective: To establish the rat model with myocardial hypoxia/reoxygenation (H/R) injury, and investigate the protective effect of EPO pretreatment on the myocardium. Methods: Sixty male adult Wistar rats were randoml...Objective: To establish the rat model with myocardial hypoxia/reoxygenation (H/R) injury, and investigate the protective effect of EPO pretreatment on the myocardium. Methods: Sixty male adult Wistar rats were randomly divided into 3 groups: control group, H/R group, and EPO group, 20 in each group. The rats in EPO group accepted injection of 5 000 U/kg recombinant human erythropoietin (RHuEPO) through vein, and the other rats accepted the injection of the same volume of saline. Twenty-four hours after the injection, rats in the EPO and H/R groups were put into the hypoxia environment for 12 h and then returned to the normoxic environment for 2 h, and then the samples of blood and myocardium were collected. Serum myocardial enzyme activity, apoptosis, ultrastructure, myocardial MDA contents, EPO receptor (EPOR) expression in cardiac myocytes and cardiac functions were tested. Results: EPOR expression was positive in cardiac myocytes of adult rat according to the result of immunonistochemitry assaying. Compared to those in H/R group, rats in EPO group presented lighter injury of myocardial ultrastructure, the reduction of serum myocardial enzyme activity, inhibition of apoptosis, the better recovery of cardiac functions, and the less production of oxygen-derived free radicals. Conclusion: Adult rat cardiac myocytes could express EPOR, and EPO pretreatment produced protective effects on myocardium with H/R injury.展开更多
Objective To compare the different effects of endothelia progenitor cells （ EPCs ） or basic fibroblast growth factor （b-FGF） intromyocardial infusion on cardiac function and neovascularization for dilated cardiomy...Objective To compare the different effects of endothelia progenitor cells （ EPCs ） or basic fibroblast growth factor （b-FGF） intromyocardial infusion on cardiac function and neovascularization for dilated cardiomyopathy（ DCM） rats. Methods Fifty adult female rats received inguinal subcutaneous injections of isoproterenol （ISO, 250 mg/kg） for induction of DCM. Four weeks later, the model rats were randomly divided into EPCs group, b-FGF group and control group. The 2×106 EPCs （ resolved in 100 μL PBS） , 100 μL b-FGF （ lO0 μg/mL ） and 100 μL PBS were evenly transplanted into the myocardium of EPCs group, b-FGF group and control group, respectively. Three months later, echocardiographic examination and regional myocardial blood flow （RMBF） measurement were performed. EPCs were traced by fluorescence in situ hybridization （FISH）. The protein and mRNA expression of b-FGF in each group was measured by ELISA assay and reverse transcription-polymerase chain reaction （ RT-PCR ） . Results Three months after transplantation, sry positive cells were detected only in EPCs group. The cardiac function as well as RMBF was significantly improved in EPCs group compared with b-FGF group or control group. There was higher capillary density in EPCs group. The protein and mRNA expression of b-FGF was stronger than b-FGF group and control group. Conclusion Transplantation of EPCs can improve cardiac function, induce neovascularization and increase RMBF for DCM rats. The treatment with EPCs has better effect than administration of b-FGF alone.展开更多
In heart disease, transforming growth factor-β1 （TGF-β1） converts fibroblasts into myofibroblasts, which synthesize and se- crete fibrillar type I and III collagens. The purpose of the present study was to investi...In heart disease, transforming growth factor-β1 （TGF-β1） converts fibroblasts into myofibroblasts, which synthesize and se- crete fibrillar type I and III collagens. The purpose of the present study was to investigate how hydrogen sulfide （HzS） sup- presses TGF-~l-induced differentiation of human cardiac fibroblasts to myofibroblasts. Human cardiac fibroblasts were se- rum-starved in fibroblast medium for 16 h before exposure to TGF-β1 （10 ng mL-1） for 24 h with or without sodium hydrosul- fide （NariS, 100 μmol L-1, 30 min pretreatment） treatment. NariS, an exogenous HzS donor, potently inhibited the prolifera- tion and migration of TGF-β1-induced human cardiac fibroblasts and regulated their cell cycle progression. Furthermore, NariS treatment led to suppression of fibroblast differentiation into myofibroblasts, and reduced the levels of collagen, TGF-β1, and activated Smad3 in TGF-β1-induced human cardiac fibroblasts in vitro. We therefore conclude that H2S sup- presses TGF-β1-stimulated conversion of fibroblasts to myofibroblasts by inhibiting the TGF-β1/Smad3 signaling pathway, as well as by inhibiting the proliferation, migration, and cell cycle progression of human cardiac myofibroblasts. These effects of H2S may play significant roles in cardiac remodeling associated with heart failure.展开更多
The T-tubule (TT) system forms the structural basis for excitation-contraction coupling in heart and muscle cells. The morphogenesis of the TT system is a key step in the maturation of heart cells because it does not ...The T-tubule (TT) system forms the structural basis for excitation-contraction coupling in heart and muscle cells. The morphogenesis of the TT system is a key step in the maturation of heart cells because it does not exist in neonatal cardiomyocytes. In the present study, we quantified the morphological changes in TTs during heart cell maturation and investigated the role of junctophilin-2 (JP2), a protein known to anchor the sarcoplasmic reticulum (SR) to TT, in changes to TT morphological parameters. Analysis of confocal images showed that the transverse elements of TTs increased, while longitudinal elements decreased during the maturation of TTs. Fourier transform analysis showed that the power of ~2 m spatial components increased with cardiomyocytes maturation. These changes were preceded by increased expression of JP2, and were reversed by JP2 knockdown. These findings indicate that JP2 is required for the morphogenesis of TTs during heart development.展开更多
基金Supplementary information is linked to the online version of the paper on the Cell Research website. Acknowledgments We thank Yun Luo, Jia Jia and Dr Yun Xu at Nanjing University, Nanjing, China, for their scientific discussions and experimental assistance. This work was supported by grants from the National Natural Science Foundation of China （Nos. 30871195, 90813035, 30890044）, the National Basic Research Program of China （Nos. 2006CB503909, 2004CB518603）, the ＂111＂ Project, the Hi-Tech Research and Development Program of China （No. 2006AA02A112,）, and the Natural Science Foundation of Jiangsu Province （Nos. BK2004082, BK2006714, BK2008021）.
文摘PGC-1α, a potent transcriptional coactivator, is the major regulator of mitochondrial biogenesis and activity in the cardiac muscle. The dysregulation of PGC-la and its target genes has been reported to be associated with congenital and acquired heart diseases. By examining myocardium samples from patients with Tetralogy of Fallot, we show here that PGC-1α expression levels are markedly increased in patients compared with healthy controls and positively correlated with the severity of cyanosis. Furthermore, hypoxia significantly induced the expression of PGC-1α and mitochondrial biogenesis in cultured cardiac myocytes. Mechanistic studies suggest that hypoxia-induced PGC-1α expression is regulated through the AMPK signaling pathway. Together, our data indicate that hypoxia can stimulate the expression of PGC-1α and mitochondrial biogenesis in the cardiac myocytes, and this process might provide a potential adaptive mechanism for cardiac myocytes to increase ATP output and minimize hypoxic damage to the heart.
文摘Objective: To establish the rat model with myocardial hypoxia/reoxygenation (H/R) injury, and investigate the protective effect of EPO pretreatment on the myocardium. Methods: Sixty male adult Wistar rats were randomly divided into 3 groups: control group, H/R group, and EPO group, 20 in each group. The rats in EPO group accepted injection of 5 000 U/kg recombinant human erythropoietin (RHuEPO) through vein, and the other rats accepted the injection of the same volume of saline. Twenty-four hours after the injection, rats in the EPO and H/R groups were put into the hypoxia environment for 12 h and then returned to the normoxic environment for 2 h, and then the samples of blood and myocardium were collected. Serum myocardial enzyme activity, apoptosis, ultrastructure, myocardial MDA contents, EPO receptor (EPOR) expression in cardiac myocytes and cardiac functions were tested. Results: EPOR expression was positive in cardiac myocytes of adult rat according to the result of immunonistochemitry assaying. Compared to those in H/R group, rats in EPO group presented lighter injury of myocardial ultrastructure, the reduction of serum myocardial enzyme activity, inhibition of apoptosis, the better recovery of cardiac functions, and the less production of oxygen-derived free radicals. Conclusion: Adult rat cardiac myocytes could express EPOR, and EPO pretreatment produced protective effects on myocardium with H/R injury.
文摘Objective To compare the different effects of endothelia progenitor cells （ EPCs ） or basic fibroblast growth factor （b-FGF） intromyocardial infusion on cardiac function and neovascularization for dilated cardiomyopathy（ DCM） rats. Methods Fifty adult female rats received inguinal subcutaneous injections of isoproterenol （ISO, 250 mg/kg） for induction of DCM. Four weeks later, the model rats were randomly divided into EPCs group, b-FGF group and control group. The 2×106 EPCs （ resolved in 100 μL PBS） , 100 μL b-FGF （ lO0 μg/mL ） and 100 μL PBS were evenly transplanted into the myocardium of EPCs group, b-FGF group and control group, respectively. Three months later, echocardiographic examination and regional myocardial blood flow （RMBF） measurement were performed. EPCs were traced by fluorescence in situ hybridization （FISH）. The protein and mRNA expression of b-FGF in each group was measured by ELISA assay and reverse transcription-polymerase chain reaction （ RT-PCR ） . Results Three months after transplantation, sry positive cells were detected only in EPCs group. The cardiac function as well as RMBF was significantly improved in EPCs group compared with b-FGF group or control group. There was higher capillary density in EPCs group. The protein and mRNA expression of b-FGF was stronger than b-FGF group and control group. Conclusion Transplantation of EPCs can improve cardiac function, induce neovascularization and increase RMBF for DCM rats. The treatment with EPCs has better effect than administration of b-FGF alone.
基金supported by the State Key Program of National Natural Science of China(81230007)
文摘In heart disease, transforming growth factor-β1 （TGF-β1） converts fibroblasts into myofibroblasts, which synthesize and se- crete fibrillar type I and III collagens. The purpose of the present study was to investigate how hydrogen sulfide （HzS） sup- presses TGF-~l-induced differentiation of human cardiac fibroblasts to myofibroblasts. Human cardiac fibroblasts were se- rum-starved in fibroblast medium for 16 h before exposure to TGF-β1 （10 ng mL-1） for 24 h with or without sodium hydrosul- fide （NariS, 100 μmol L-1, 30 min pretreatment） treatment. NariS, an exogenous HzS donor, potently inhibited the prolifera- tion and migration of TGF-β1-induced human cardiac fibroblasts and regulated their cell cycle progression. Furthermore, NariS treatment led to suppression of fibroblast differentiation into myofibroblasts, and reduced the levels of collagen, TGF-β1, and activated Smad3 in TGF-β1-induced human cardiac fibroblasts in vitro. We therefore conclude that H2S sup- presses TGF-β1-stimulated conversion of fibroblasts to myofibroblasts by inhibiting the TGF-β1/Smad3 signaling pathway, as well as by inhibiting the proliferation, migration, and cell cycle progression of human cardiac myofibroblasts. These effects of H2S may play significant roles in cardiac remodeling associated with heart failure.
基金supported by the National Basic Research Program of China (2011CB809101)the National Natural Science Foundation of China (30730013)
文摘The T-tubule (TT) system forms the structural basis for excitation-contraction coupling in heart and muscle cells. The morphogenesis of the TT system is a key step in the maturation of heart cells because it does not exist in neonatal cardiomyocytes. In the present study, we quantified the morphological changes in TTs during heart cell maturation and investigated the role of junctophilin-2 (JP2), a protein known to anchor the sarcoplasmic reticulum (SR) to TT, in changes to TT morphological parameters. Analysis of confocal images showed that the transverse elements of TTs increased, while longitudinal elements decreased during the maturation of TTs. Fourier transform analysis showed that the power of ~2 m spatial components increased with cardiomyocytes maturation. These changes were preceded by increased expression of JP2, and were reversed by JP2 knockdown. These findings indicate that JP2 is required for the morphogenesis of TTs during heart development.
