Aim In diabetic patients, metformin appears to provide cardiovascular protection that cannot be attribu- ted only to its antihyperglycemic effects. Metformin is also known as the AMP-activated protein kinase （AMPK） ...Aim In diabetic patients, metformin appears to provide cardiovascular protection that cannot be attribu- ted only to its antihyperglycemic effects. Metformin is also known as the AMP-activated protein kinase （AMPK） ac- tivator. Our previous study suggested that metformin inhibits transforming growth factor-β1 （TGF-β1） production in a mouse heart failure model of pressure overload. TGF-β1 is a key factor in cardiac fibrosis and is usually induced by Angiotensin Ⅱ （Ang Ⅱ ） in the pressure overload mouse models. This study investigated the effect of metformin on cardiac fibrosis and TGF-β production induced by AngII and the underlying mechanisms. Methods C57/BL6 wild-type and AMPKα2 knockout mice were used. AngII （3 mg · kg-1 · d-1） was infused subcutaneously into mice for 7 days. Adult mouse cardiac fibroblasts were isolated and treated with AngII （ 1 μmol · L-1） and/or met- formin （1 mmol · L-l）. Results In C57/BL6 mice, metformin inhibits AngII-induced cardiac fibrosis. In cardi-ac fibroblasts, metformin inhibits TGF-β1 expression and production induced by AngII. AMPK inhibitor, com- pound C, reversed the effects of metformin. In vivo, AMPKα2 deficiency further increases AngII-induced TGF-β1 production. In cardiac fibroblasts, metformin inhibited AngII induced hepatocyte nuclear factor4 （HNF4ot protein level increase and HNF4α binding with TGF-β1 promoter using chromatin immunoprecipitation assay. In vivo, AMPKα2 deficiency further increased AngII-induced HNF4α protein level. Using HNF4α adenovirus, overexpress- ing HNF4α led to a 1.5-fold increase in TGF-β1 mRNA expression. HNF4a siRNA blocked AngII induced TGF- β1 production. Luciferase reporter with deleted HNF4a binding sites showed decreased TGFbl transcriptional activ- ity induced by AngII. In AMPK or2-/- heart, the inhibition of metformin on HNF4a protein was attenuated. Con- clusion Metformin inhibits AngII induced cardiac fibrosis and TGF-β1 production through AMPK activation. The underlying mechanism is that AMPK activation inhibits AngII induced HNF4α and then decreases TGF-β1 expres- sion.展开更多
目的探究微小RNA-195-5p(microRNA-195-5p,miR-195-5p)对心房颤动(atrial fibrillation,AF)大鼠心肌纤维化的影响与机制。方法选择雄性SD大鼠72只,随机分为对照组、AF组、阴性对照组、miR-195-5p组(miR-195-5p抑制剂)、9型重组腺相关病...目的探究微小RNA-195-5p(microRNA-195-5p,miR-195-5p)对心房颤动(atrial fibrillation,AF)大鼠心肌纤维化的影响与机制。方法选择雄性SD大鼠72只,随机分为对照组、AF组、阴性对照组、miR-195-5p组(miR-195-5p抑制剂)、9型重组腺相关病毒(recombinant adeno-associated virus serotype 9,rAAV9)组(miR-195-5p抑制剂+rAAV9-阴性对照)、联合组[miR-195-5p抑制剂+rAAV9-小干扰RNA-SMAD同源物(SMAD homolog,Smad)]7,每组12只。除对照组外,其他组大鼠构建AF模型。给予对应干预措施后,进行心电图测试,记录AF发生率和持续时间;HE染色检测心肌组织病理变化;Masson染色检测心肌组织纤维化程度;实时荧光定量聚合酶链反应检测心肌组织miR-195-5p、Smad7mRNA表达;Western blot检测心肌组织转化生长因子β_(1)(transforming growth factor-β_(1),TGF-β_(1))、Smad2、磷酸化Smad2、Smad3、磷酸化Smad3、Smad7、Ⅰ型胶原蛋白(Collagen-Ⅰ)、Ⅲ型胶原蛋白(Collagen-Ⅲ)表达;双荧光素酶实验验证miR-195-5p对Smad7的调控作用。结果与对照组比较,AF组AF发生率(75.0%vs 0)和持续时间[(27.02±2.65)s vs 0s]、胶原容积分数[(14.47±0.89)%vs(2.12±0.35)%]、心肌组织miR-195-5p(3.27±0.21 vs 1.00±0.10)、TGF-β_(1)(0.76±0.08 vs 0.23±0.04)、Collagen-Ⅰ(0.58±0.07 vs 0.20±0.04)、Collagen-Ⅲ(0.46±0.05 vs 0.11±0.02)、磷酸化Smad2/Smad2(0.92±0.10 vs 0.37±0.05)、磷酸化Smad3/Smad3(0.65±0.06 vs 0.14±0.03)表达明显升高,Smad7mRNA(0.32±0.06 vs 1.02±0.09)和Smad7(0.19±0.03 vs 0.58±0.07)表达明显降低,差异有统计学意义(P<0.05);与AF组和阴性对照组比较,miR-195-5p组AF发生率和持续时间、胶原容积分数、心肌组织miR-195-5p、TGF-β_(1)、Collagen-Ⅰ、Collagen-Ⅲ、磷酸化Smad2/Smad2和磷酸化Smad3/Smad3表达明显降低,Smad7mRNA和蛋白表达明显升高,差异有统计学意义(P<0.05);与miR-195-5p组和rAAV9组比较,联合组AF发生率和持续时间、胶原容积分数、心肌组织TGF-β_(1)、Collagen-Ⅰ、Collagen-Ⅲ、磷酸化Smad2/Smad2和磷酸化Smad3/Smad3表达明显升高,Smad7mRNA和Smad7表达明显降低,差异有统计学意义(P<0.05)。结论下调miR-195-5p可能靶向Smad7抑制TGF-β_(1)信号传导,从而减轻AF心肌纤维化。展开更多
目的肾小管间质纤维化(TIF)是反映肾功能下降严重程度和及判断预后的最重要指标,硫化氢(H_2S)在维持肾的正常功能和多种肾损伤疾病中都起着关键作用。文中通过建立单侧输尿管梗阻模型(UUO)观察外源性补充硫化氢(H_2S)供体硫氢化钠(Na HS...目的肾小管间质纤维化(TIF)是反映肾功能下降严重程度和及判断预后的最重要指标,硫化氢(H_2S)在维持肾的正常功能和多种肾损伤疾病中都起着关键作用。文中通过建立单侧输尿管梗阻模型(UUO)观察外源性补充硫化氢(H_2S)供体硫氢化钠(Na HS)对单侧输尿管梗阻(UUO)大鼠肾组织中血管紧张素Ⅱ(AngⅡ)、增殖细胞核抗原(PCNA)和转化生长因子-β1(TGF-β1)表达的影响。方法单侧输尿管梗阻建立TIF动物模型,96只SD大鼠随机数字表法分为假手术组、模型组,以及Na HS低、高剂量组,每组24只。模型组大鼠行左侧输尿管结扎,假手术组大鼠仅游离输尿管而不进行结扎。Na HS低、高剂量组治疗组大鼠在UUO制备后分别给予腹腔注射Na HS 1.4μmol/kg(0.2μmol/m L)和7μmol/kg(1μmol/m L),假手术组及模型组分别腹腔注射等量等渗盐水。术后第7、14、21天分别进行HE、Masson染色和免疫组化染色。测定大鼠肾间质纤维化相对面积以及肾组织AngⅡ、TGF-β1、PCNA相对表达。结果假手术组各时间点AngⅡ、PCNA和TGF-β1在肾小管间质微量表达。模型组较假手术组7、14、21 d AngⅡ表达升高(6.27±0.78 vs 1.09±0.75,8.94±0.31 vs 1.20±0.06,13.75±0.39 vs1.34±0.69;P<0.01)、PCNA表达升高(82.81±5.36 vs 4.63±0.83,101.00±4.3 vs 8.57±1.09,118.11±4.70 vs 13.15±1.43;P<0.01),TGF-β1表达亦升高(9.18±0.83 vs 0.98±0.14,16.87±0.77 vs 1.85±0.20,20.29±0.89 vs 2.43±0.14,P<0.01)。与模型组比较,Na HS低、高剂量组AngⅡ、PCNA和TGF-β1表达均降低(P<0.05)。但Na HS低、高剂量组之间差异无统计学意义(P>0.05)。结论外源性补充H_2S可部分通过下调AngⅡ、PCNA和TGF-β1的表达延缓TIF的进展。展开更多
文摘Aim In diabetic patients, metformin appears to provide cardiovascular protection that cannot be attribu- ted only to its antihyperglycemic effects. Metformin is also known as the AMP-activated protein kinase （AMPK） ac- tivator. Our previous study suggested that metformin inhibits transforming growth factor-β1 （TGF-β1） production in a mouse heart failure model of pressure overload. TGF-β1 is a key factor in cardiac fibrosis and is usually induced by Angiotensin Ⅱ （Ang Ⅱ ） in the pressure overload mouse models. This study investigated the effect of metformin on cardiac fibrosis and TGF-β production induced by AngII and the underlying mechanisms. Methods C57/BL6 wild-type and AMPKα2 knockout mice were used. AngII （3 mg · kg-1 · d-1） was infused subcutaneously into mice for 7 days. Adult mouse cardiac fibroblasts were isolated and treated with AngII （ 1 μmol · L-1） and/or met- formin （1 mmol · L-l）. Results In C57/BL6 mice, metformin inhibits AngII-induced cardiac fibrosis. In cardi-ac fibroblasts, metformin inhibits TGF-β1 expression and production induced by AngII. AMPK inhibitor, com- pound C, reversed the effects of metformin. In vivo, AMPKα2 deficiency further increases AngII-induced TGF-β1 production. In cardiac fibroblasts, metformin inhibited AngII induced hepatocyte nuclear factor4 （HNF4ot protein level increase and HNF4α binding with TGF-β1 promoter using chromatin immunoprecipitation assay. In vivo, AMPKα2 deficiency further increased AngII-induced HNF4α protein level. Using HNF4α adenovirus, overexpress- ing HNF4α led to a 1.5-fold increase in TGF-β1 mRNA expression. HNF4a siRNA blocked AngII induced TGF- β1 production. Luciferase reporter with deleted HNF4a binding sites showed decreased TGFbl transcriptional activ- ity induced by AngII. In AMPK or2-/- heart, the inhibition of metformin on HNF4a protein was attenuated. Con- clusion Metformin inhibits AngII induced cardiac fibrosis and TGF-β1 production through AMPK activation. The underlying mechanism is that AMPK activation inhibits AngII induced HNF4α and then decreases TGF-β1 expres- sion.
文摘目的探究微小RNA-195-5p(microRNA-195-5p,miR-195-5p)对心房颤动(atrial fibrillation,AF)大鼠心肌纤维化的影响与机制。方法选择雄性SD大鼠72只,随机分为对照组、AF组、阴性对照组、miR-195-5p组(miR-195-5p抑制剂)、9型重组腺相关病毒(recombinant adeno-associated virus serotype 9,rAAV9)组(miR-195-5p抑制剂+rAAV9-阴性对照)、联合组[miR-195-5p抑制剂+rAAV9-小干扰RNA-SMAD同源物(SMAD homolog,Smad)]7,每组12只。除对照组外,其他组大鼠构建AF模型。给予对应干预措施后,进行心电图测试,记录AF发生率和持续时间;HE染色检测心肌组织病理变化;Masson染色检测心肌组织纤维化程度;实时荧光定量聚合酶链反应检测心肌组织miR-195-5p、Smad7mRNA表达;Western blot检测心肌组织转化生长因子β_(1)(transforming growth factor-β_(1),TGF-β_(1))、Smad2、磷酸化Smad2、Smad3、磷酸化Smad3、Smad7、Ⅰ型胶原蛋白(Collagen-Ⅰ)、Ⅲ型胶原蛋白(Collagen-Ⅲ)表达;双荧光素酶实验验证miR-195-5p对Smad7的调控作用。结果与对照组比较,AF组AF发生率(75.0%vs 0)和持续时间[(27.02±2.65)s vs 0s]、胶原容积分数[(14.47±0.89)%vs(2.12±0.35)%]、心肌组织miR-195-5p(3.27±0.21 vs 1.00±0.10)、TGF-β_(1)(0.76±0.08 vs 0.23±0.04)、Collagen-Ⅰ(0.58±0.07 vs 0.20±0.04)、Collagen-Ⅲ(0.46±0.05 vs 0.11±0.02)、磷酸化Smad2/Smad2(0.92±0.10 vs 0.37±0.05)、磷酸化Smad3/Smad3(0.65±0.06 vs 0.14±0.03)表达明显升高,Smad7mRNA(0.32±0.06 vs 1.02±0.09)和Smad7(0.19±0.03 vs 0.58±0.07)表达明显降低,差异有统计学意义(P<0.05);与AF组和阴性对照组比较,miR-195-5p组AF发生率和持续时间、胶原容积分数、心肌组织miR-195-5p、TGF-β_(1)、Collagen-Ⅰ、Collagen-Ⅲ、磷酸化Smad2/Smad2和磷酸化Smad3/Smad3表达明显降低,Smad7mRNA和蛋白表达明显升高,差异有统计学意义(P<0.05);与miR-195-5p组和rAAV9组比较,联合组AF发生率和持续时间、胶原容积分数、心肌组织TGF-β_(1)、Collagen-Ⅰ、Collagen-Ⅲ、磷酸化Smad2/Smad2和磷酸化Smad3/Smad3表达明显升高,Smad7mRNA和Smad7表达明显降低,差异有统计学意义(P<0.05)。结论下调miR-195-5p可能靶向Smad7抑制TGF-β_(1)信号传导,从而减轻AF心肌纤维化。
文摘目的肾小管间质纤维化(TIF)是反映肾功能下降严重程度和及判断预后的最重要指标,硫化氢(H_2S)在维持肾的正常功能和多种肾损伤疾病中都起着关键作用。文中通过建立单侧输尿管梗阻模型(UUO)观察外源性补充硫化氢(H_2S)供体硫氢化钠(Na HS)对单侧输尿管梗阻(UUO)大鼠肾组织中血管紧张素Ⅱ(AngⅡ)、增殖细胞核抗原(PCNA)和转化生长因子-β1(TGF-β1)表达的影响。方法单侧输尿管梗阻建立TIF动物模型,96只SD大鼠随机数字表法分为假手术组、模型组,以及Na HS低、高剂量组,每组24只。模型组大鼠行左侧输尿管结扎,假手术组大鼠仅游离输尿管而不进行结扎。Na HS低、高剂量组治疗组大鼠在UUO制备后分别给予腹腔注射Na HS 1.4μmol/kg(0.2μmol/m L)和7μmol/kg(1μmol/m L),假手术组及模型组分别腹腔注射等量等渗盐水。术后第7、14、21天分别进行HE、Masson染色和免疫组化染色。测定大鼠肾间质纤维化相对面积以及肾组织AngⅡ、TGF-β1、PCNA相对表达。结果假手术组各时间点AngⅡ、PCNA和TGF-β1在肾小管间质微量表达。模型组较假手术组7、14、21 d AngⅡ表达升高(6.27±0.78 vs 1.09±0.75,8.94±0.31 vs 1.20±0.06,13.75±0.39 vs1.34±0.69;P<0.01)、PCNA表达升高(82.81±5.36 vs 4.63±0.83,101.00±4.3 vs 8.57±1.09,118.11±4.70 vs 13.15±1.43;P<0.01),TGF-β1表达亦升高(9.18±0.83 vs 0.98±0.14,16.87±0.77 vs 1.85±0.20,20.29±0.89 vs 2.43±0.14,P<0.01)。与模型组比较,Na HS低、高剂量组AngⅡ、PCNA和TGF-β1表达均降低(P<0.05)。但Na HS低、高剂量组之间差异无统计学意义(P>0.05)。结论外源性补充H_2S可部分通过下调AngⅡ、PCNA和TGF-β1的表达延缓TIF的进展。
