血管衰老是伴随年龄增长而出现的血管结构和功能的改变,主要包括血管重塑、血管稳态失衡以及血管细胞的衰老.表观遗传调控是在不改变 DNA 序列的情况下改变基因的表达,其主要机制包括 DNA 甲基化、组蛋白修饰以及非编码 RNA 的调控等....血管衰老是伴随年龄增长而出现的血管结构和功能的改变,主要包括血管重塑、血管稳态失衡以及血管细胞的衰老.表观遗传调控是在不改变 DNA 序列的情况下改变基因的表达,其主要机制包括 DNA 甲基化、组蛋白修饰以及非编码 RNA 的调控等.目前的研究表明各种表观遗传调控途径参与血管衰老的各个层面,在血管衰老及相关疾病的发生发展中扮演重要角色.靶向表观遗传调控的药物有望成为衰老相关疾病新的治疗方向.展开更多
SIRT1,a mammalian ortholog of yeast silent information regulator 2(Sir2),is an NAD+-dependent protein deacetylase that plays a critical role in the regulation of vascular function.The current study aims to investigate...SIRT1,a mammalian ortholog of yeast silent information regulator 2(Sir2),is an NAD+-dependent protein deacetylase that plays a critical role in the regulation of vascular function.The current study aims to investigate the functional significance of deacetylase activity of SIRT1 in heart.Here we show that the early postnatal hearts expressed the highest level of SIRT1deacetylase activity compared to adult and aged hearts.We generated transgenic mice with cardiac-specific expression of a dominant-negative form of the human SIRT1(SIRT1H363Y),which represses endogenous SIRT1 activity.The transgenic mice displayed dilated atrial and ventricular chambers,and died early in the postnatal period.Pathological,echocardiographic and molecular phenotype confirmed the presence of dilated cardiomyopathy.Terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling analysis revealed a greater abundance of apoptotic nuclei in the hearts of transgenic mice.Furthermore,we show that cardiomyocyte apoptosis caused by suppression of SIRT1 activity is,at least in part,due to increased p53acetylation and upregulated Bax expression.These results indicate that dominant negative form of SIRT1(SIRT1H363Y)overexpression in mouse hearts causes cardiomyocyte apoptosis and early-onset heart failure,suggesting a critical role of SIRT1 in preserving normal cardiac development during the early postnatal period.展开更多
The rapidly increasing prevalence of diabetes mellitus worldwide is one of the most serious and challenging health problems in the 21st century. Mammalian sirtuin 1 （SIRT1） has been shown to decrease high-glucose-in...The rapidly increasing prevalence of diabetes mellitus worldwide is one of the most serious and challenging health problems in the 21st century. Mammalian sirtuin 1 （SIRT1） has been shown to decrease high-glucose-induced endothelial cell senescence in vitro and prevent hyperglycemia-induced vascular dysfunction. However, a role for SIRTI in prevention of hyperglyce- mia-induced vascular cell senescence in vivo remains unclear. We used endothelium-specific SIRT1 transgenic （SIRT1-Tg） mice and wild-type （WT） mice to construct a 40-week streptozotocin （STZ）-induced diabetic mouse model. In this mode, 42.9% of wild-type （WT） mice and 38.5% of SIRT1-Tg mice were successfully established as diabetic. Forty weeks of hyper- glycemia induced significant vascular cell senescence in aortas of mice, as indicated by upregulation of expression of senes- cence-associated markers including p53, p21 and plasminogen activator inhibitor-1 （PAI-1）. However, SIRT1-Tg diabetic mice displayed dramatically decreased expression of p53, p21 and PAI-I compared with diabetic WT mice. Moreover, man- ganese superoxide dismutase expression （MnSOD） was significantly downregulated in the aortas of diabetic WT mice, but was preserved in diabetic SIRT1-Tg mice. Furthermore, expression of the oxidative stress adaptor p66Shc was significantly de- creased in aortas of SIRT1-Tg diabetic mice compared with WT diabetic mice. Overall, these findings suggest that SIRT 1-mediated inhibition of hyperglycemia-induced vascular cell senescence is mediated at least partly through the reduction of oxidative stress.展开更多
Intercellular adhesion molecule-1 （ICAM-1） plays an important role in the recruitment of leukocytes to the endothelium, which causes inflammation and initiation of atherosclerosis. We have previously shown that endo...Intercellular adhesion molecule-1 （ICAM-1） plays an important role in the recruitment of leukocytes to the endothelium, which causes inflammation and initiation of atherosclerosis. We have previously shown that endothelium-specific over-expression of class III deacetylase SIRT1 decreases atherosclerosis. We therefore addressed the hypothesis that SIRT1 suppresses ICAM-1 expression in the endothelial cells. Here, we found that expression of SIRT1 and ICAM-1 was significantly induced by PMA and ionomycin （PMA/Io） in human umbilical vein endothelial cells （HUVECs）. Adenovirus-mediated over-expression of SIRT1 significantly inhibited PMA/Io-induced ICAM-1 expression （RNAi） resulted in increased expression of ICAM-1 in HUVECs in HUVECs. Knockdown of SIRT1 by RNA interference Luciferase report assay showed that over-expression of SIRT1 suppressed ICAM-1 promoter activity both in basic and in PMA/Io-induced conditions. We further found that SIRT1 was involved in transcription complex binding on the ICAM-1 promoter by chromatin immunoprecipitation （CHIP） assays. Furthermore, SIRT1 RNAi increased NF-~：B p65 binding ability to the ICAM-1 promoter by ChIP assays. Overall, these data suggests that SIRT1 inhibits ICAM-1 expression in endothelial cells, which may contribute to its anti-atherosclerosis effect.展开更多
Background Therapeutic angiogenesis has been shown to promote blood vessel growth and improve tissue perfusion. Vascular endothelial growth factor （VEGF） plays an important role in angiogenesis. However, it has side...Background Therapeutic angiogenesis has been shown to promote blood vessel growth and improve tissue perfusion. Vascular endothelial growth factor （VEGF） plays an important role in angiogenesis. However, it has side effects that limit its therapeutic utility in vivo, especially at high concentrations. This study aimed to investigate whether an intramuscular injection of a genetically engineered zinc finger VEGF-activating transcription factor modulates the endothelial progenitor cells （EPC） and promotes therapeutic angiogenesis in a hindlimb ischemia model with type 1 diabetes. Methods AIIoxan （intravenous injection） was used to induce type I diabetes in C57BL/6 mice （n=58）. The ischemic limb received ZFP-VEGF （125 pg ZFP-VEGF plasmid in 1% poloxamer） or placebo （1% poloxamer） intramuscularly. Mice were sacrificed 3, 5, 10, or 20 days post-injection. Limb blood flow was monitored using laser Doppler perfusion imaging. VEGF mRNA and protein expression were examined using real-time PCR and ELISA, respectively. Capillary density, proliferation, and apoptosis were examined using immunohistochemistry techniques. Flow cytometry was used to detect the EPC population in bone marrow. Two-tailed Student＇s paired t test and repeated-measures analysis of variance were used for statistical analysis. Results ZFP-VEGF increased VEGF mRNA and protein expression at 3 and 10 days post-injection, and increased EPC in bone marrow at day 5 and 20 post-injection compared with controls （P〈0.05）. ZFP-VEGF treatment resulted in better perfusion recovery, a higher capillary density and proliferation, and less apoptosis compared with controls （P〈0.05）. Conclusions Intramuscular ZFP-VEGF injection promotes therapeutic angiogenesis in an ischemic hindlimb model with type 1 diabetes. This might be due to the effects of VEGF on cell survival and EPC recruitment.展开更多
Calorie restriction(CR)is a dietary regime based on low calorie intake.CR without malnutrition extends lifespan in a wide range of organisms from yeast to rodents,and CR can prevent and delay the onset of age-related ...Calorie restriction(CR)is a dietary regime based on low calorie intake.CR without malnutrition extends lifespan in a wide range of organisms from yeast to rodents,and CR can prevent and delay the onset of age-related functional decline and diseases in human and non-human primates.CR is a safe and effective intervention to reduce vascular risk factors in humans.In recent years,studies in rodents have provided mechanistic insights into the beneficial effects of CR on vascular homeostasis,including reduced oxidative stress,enhanced nitric oxide(NO)bioactivity,and decreased inflammation.A number of important molecules,including sirtuins,AMP-activated protein kinase,mammalian targets of rapamycin,endothelial nitric oxidase and their regulatory pathways are involved in the maintenance of vascular homeostasis.Evidence has shown that these pathways are responsible for many aspects of CR’s effects,and that they may also mediate the effects of CR on vasculature.展开更多
文摘血管衰老是伴随年龄增长而出现的血管结构和功能的改变,主要包括血管重塑、血管稳态失衡以及血管细胞的衰老.表观遗传调控是在不改变 DNA 序列的情况下改变基因的表达,其主要机制包括 DNA 甲基化、组蛋白修饰以及非编码 RNA 的调控等.目前的研究表明各种表观遗传调控途径参与血管衰老的各个层面,在血管衰老及相关疾病的发生发展中扮演重要角色.靶向表观遗传调控的药物有望成为衰老相关疾病新的治疗方向.
基金supported by the National Natural Science Foundation of China(31271227,81161120551)the National Basic Research Program of China(2011CB503902)
文摘SIRT1,a mammalian ortholog of yeast silent information regulator 2(Sir2),is an NAD+-dependent protein deacetylase that plays a critical role in the regulation of vascular function.The current study aims to investigate the functional significance of deacetylase activity of SIRT1 in heart.Here we show that the early postnatal hearts expressed the highest level of SIRT1deacetylase activity compared to adult and aged hearts.We generated transgenic mice with cardiac-specific expression of a dominant-negative form of the human SIRT1(SIRT1H363Y),which represses endogenous SIRT1 activity.The transgenic mice displayed dilated atrial and ventricular chambers,and died early in the postnatal period.Pathological,echocardiographic and molecular phenotype confirmed the presence of dilated cardiomyopathy.Terminal deoxynucleotidyl transferase-mediated dUTP nick-end-labeling analysis revealed a greater abundance of apoptotic nuclei in the hearts of transgenic mice.Furthermore,we show that cardiomyocyte apoptosis caused by suppression of SIRT1 activity is,at least in part,due to increased p53acetylation and upregulated Bax expression.These results indicate that dominant negative form of SIRT1(SIRT1H363Y)overexpression in mouse hearts causes cardiomyocyte apoptosis and early-onset heart failure,suggesting a critical role of SIRT1 in preserving normal cardiac development during the early postnatal period.
基金supported by the National Basic Research Program of China (Grant No. 2011CB503902)National Natural Science Foundation of China (Grant Nos. 31028005 and 31021091)
文摘The rapidly increasing prevalence of diabetes mellitus worldwide is one of the most serious and challenging health problems in the 21st century. Mammalian sirtuin 1 （SIRT1） has been shown to decrease high-glucose-induced endothelial cell senescence in vitro and prevent hyperglycemia-induced vascular dysfunction. However, a role for SIRTI in prevention of hyperglyce- mia-induced vascular cell senescence in vivo remains unclear. We used endothelium-specific SIRT1 transgenic （SIRT1-Tg） mice and wild-type （WT） mice to construct a 40-week streptozotocin （STZ）-induced diabetic mouse model. In this mode, 42.9% of wild-type （WT） mice and 38.5% of SIRT1-Tg mice were successfully established as diabetic. Forty weeks of hyper- glycemia induced significant vascular cell senescence in aortas of mice, as indicated by upregulation of expression of senes- cence-associated markers including p53, p21 and plasminogen activator inhibitor-1 （PAI-1）. However, SIRT1-Tg diabetic mice displayed dramatically decreased expression of p53, p21 and PAI-I compared with diabetic WT mice. Moreover, man- ganese superoxide dismutase expression （MnSOD） was significantly downregulated in the aortas of diabetic WT mice, but was preserved in diabetic SIRT1-Tg mice. Furthermore, expression of the oxidative stress adaptor p66Shc was significantly de- creased in aortas of SIRT1-Tg diabetic mice compared with WT diabetic mice. Overall, these findings suggest that SIRT 1-mediated inhibition of hyperglycemia-induced vascular cell senescence is mediated at least partly through the reduction of oxidative stress.
基金supported by National Natural Science Foundation of China(31271227,31028005,31021091)National Basic Research Program of China (2011CB503902,2012BAI39B03)
文摘Intercellular adhesion molecule-1 （ICAM-1） plays an important role in the recruitment of leukocytes to the endothelium, which causes inflammation and initiation of atherosclerosis. We have previously shown that endothelium-specific over-expression of class III deacetylase SIRT1 decreases atherosclerosis. We therefore addressed the hypothesis that SIRT1 suppresses ICAM-1 expression in the endothelial cells. Here, we found that expression of SIRT1 and ICAM-1 was significantly induced by PMA and ionomycin （PMA/Io） in human umbilical vein endothelial cells （HUVECs）. Adenovirus-mediated over-expression of SIRT1 significantly inhibited PMA/Io-induced ICAM-1 expression （RNAi） resulted in increased expression of ICAM-1 in HUVECs in HUVECs. Knockdown of SIRT1 by RNA interference Luciferase report assay showed that over-expression of SIRT1 suppressed ICAM-1 promoter activity both in basic and in PMA/Io-induced conditions. We further found that SIRT1 was involved in transcription complex binding on the ICAM-1 promoter by chromatin immunoprecipitation （CHIP） assays. Furthermore, SIRT1 RNAi increased NF-~：B p65 binding ability to the ICAM-1 promoter by ChIP assays. Overall, these data suggests that SIRT1 inhibits ICAM-1 expression in endothelial cells, which may contribute to its anti-atherosclerosis effect.
基金This work was supported by a grant from the National Natural Science Foundation of China （No, 81270399）.
文摘Background Therapeutic angiogenesis has been shown to promote blood vessel growth and improve tissue perfusion. Vascular endothelial growth factor （VEGF） plays an important role in angiogenesis. However, it has side effects that limit its therapeutic utility in vivo, especially at high concentrations. This study aimed to investigate whether an intramuscular injection of a genetically engineered zinc finger VEGF-activating transcription factor modulates the endothelial progenitor cells （EPC） and promotes therapeutic angiogenesis in a hindlimb ischemia model with type 1 diabetes. Methods AIIoxan （intravenous injection） was used to induce type I diabetes in C57BL/6 mice （n=58）. The ischemic limb received ZFP-VEGF （125 pg ZFP-VEGF plasmid in 1% poloxamer） or placebo （1% poloxamer） intramuscularly. Mice were sacrificed 3, 5, 10, or 20 days post-injection. Limb blood flow was monitored using laser Doppler perfusion imaging. VEGF mRNA and protein expression were examined using real-time PCR and ELISA, respectively. Capillary density, proliferation, and apoptosis were examined using immunohistochemistry techniques. Flow cytometry was used to detect the EPC population in bone marrow. Two-tailed Student＇s paired t test and repeated-measures analysis of variance were used for statistical analysis. Results ZFP-VEGF increased VEGF mRNA and protein expression at 3 and 10 days post-injection, and increased EPC in bone marrow at day 5 and 20 post-injection compared with controls （P〈0.05）. ZFP-VEGF treatment resulted in better perfusion recovery, a higher capillary density and proliferation, and less apoptosis compared with controls （P〈0.05）. Conclusions Intramuscular ZFP-VEGF injection promotes therapeutic angiogenesis in an ischemic hindlimb model with type 1 diabetes. This might be due to the effects of VEGF on cell survival and EPC recruitment.
基金supported by the National Natural Science Foundation of China (31271227,91339201)the Beijing Nova Program (XX2013064)the National Basic Research Program of China (2011CB503902)
文摘Calorie restriction(CR)is a dietary regime based on low calorie intake.CR without malnutrition extends lifespan in a wide range of organisms from yeast to rodents,and CR can prevent and delay the onset of age-related functional decline and diseases in human and non-human primates.CR is a safe and effective intervention to reduce vascular risk factors in humans.In recent years,studies in rodents have provided mechanistic insights into the beneficial effects of CR on vascular homeostasis,including reduced oxidative stress,enhanced nitric oxide(NO)bioactivity,and decreased inflammation.A number of important molecules,including sirtuins,AMP-activated protein kinase,mammalian targets of rapamycin,endothelial nitric oxidase and their regulatory pathways are involved in the maintenance of vascular homeostasis.Evidence has shown that these pathways are responsible for many aspects of CR’s effects,and that they may also mediate the effects of CR on vasculature.
