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
目的研究长春市35~79岁汉族人群维生素D受体基因BsmⅠ、FokⅠ位点多态性的分布特征及其与腰椎骨密度(bone mineral density,BMD)的相关性,分析不同基因型对骨代谢的调节与影响,同时研究血清TGF-β、TRACP水平与腰椎BMD的相关性,为骨质...目的研究长春市35~79岁汉族人群维生素D受体基因BsmⅠ、FokⅠ位点多态性的分布特征及其与腰椎骨密度(bone mineral density,BMD)的相关性,分析不同基因型对骨代谢的调节与影响,同时研究血清TGF-β、TRACP水平与腰椎BMD的相关性,为骨质疏松预防、早期诊断和治疗提供分子生物学依据。方法应用Hologic Discovery WA型骨密度仪检测腰椎正位(L1-L4)BMD;采用聚合酶链反应-限制性片段长度多态性(PCR-RFLP)分析BsmⅠ和FokⅠ位点多态性;采用酶联免疫吸附分析法检测血清TGF-β、TRACP水平;采用SPSS 23.0软件进行统计分析。结果在500名汉族人群中,BsmⅠ位点基因型以bb型为主,占80.2%,Bb型占15.2%,BB型占4.6%;FokⅠ位点ff基因型占18.6%,Ff型占45.8%,FF型占35.6%。BsmⅠ位点各基因型骨质疏松组与非骨质疏松组分布特征组间差异无统计学意义(P>0.05);FokⅠ位点ff基因型骨质疏松组所占比例高于非骨质疏松组,差异有统计学意义(P<0.05)。BsmⅠ位点bb基因型男性、女性BMD值均低于Bb型和BB型,但差异无统计学意义(P>0.05);FokⅠ位点ff基因型男性、女性BMD值均低于Ff型和FF型,差异有统计学意义(P<0.05)。血清TGF-β水平骨质疏松组显著低于非骨质疏松组,而TRACP水平骨质疏松组高于非骨质疏松组,组间差异有统计学意义(P<0.05)。结论本研究500名汉族人群中,BsmⅠ位点以bb基因型为主,占80.2%,各基因型骨密度值组间差异无统计学意义;FokⅠ位点ff型BMD值低于Ff型和FF型,骨质疏松组ff基因型所占比例高于非骨质疏松组,差异有统计学意义,提示ff基因型可能是骨质疏松发生的危险因素;骨质疏松组血清TGF-β水平显著低于非骨质疏松组,而TRACP水平高于非骨质疏松组,差异有统计学意义,表明TGF-β、TRACP是评价骨代谢状态的良好指标。展开更多
目的:探讨转化生长因子β1(TGF-β1)对大鼠心肌细胞肥大和凋亡的影响。方法:建立TGF-β1诱导的体外大鼠心肌细胞肥大模型。透射电镜观察心肌细胞形态。碘化丙啶(PI)染色标记法检测心肌细胞RNA含量。实时荧光定量PCR(Real time PCR)检测...目的:探讨转化生长因子β1(TGF-β1)对大鼠心肌细胞肥大和凋亡的影响。方法:建立TGF-β1诱导的体外大鼠心肌细胞肥大模型。透射电镜观察心肌细胞形态。碘化丙啶(PI)染色标记法检测心肌细胞RNA含量。实时荧光定量PCR(Real time PCR)检测心肌细胞胚心基因肌球蛋白重链β亚型(β-MHC)的表达。TdT-FragEL染色检测心肌细胞凋亡。Annexin/7AAD双染法、直接免疫荧光标记法经流式细胞仪检测心肌细胞凋亡率及心肌细胞中caspase-3水平。结果:TGF-β1刺激24 h后,心肌细胞β-MHC mRNA水平明显高于对照组(P<0.01);PI染色结果TGF-β1组RNA含量明显增高,并呈剂量依赖性(P<0.01)。TdT-FragEL染色观察,TGF-β1可增加心肌细胞凋亡率(P<0.01)。与对照组相比,TGF-β1可明显上调心肌细胞中caspase-3(P<0.01);TGF-β1诱导的心肌细胞凋亡率增加(P<0.01)。透射电镜观察TGF-β1可诱导心肌细胞肥大和凋亡。结论:TGF-β1可同时诱导心肌细胞肥大和凋亡,诱导凋亡可能与caspase-3有关。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:探讨转化生长因子β1(TGF-β1)对大鼠心肌细胞肥大和凋亡的影响。方法:建立TGF-β1诱导的体外大鼠心肌细胞肥大模型。透射电镜观察心肌细胞形态。碘化丙啶(PI)染色标记法检测心肌细胞RNA含量。实时荧光定量PCR(Real time PCR)检测心肌细胞胚心基因肌球蛋白重链β亚型(β-MHC)的表达。TdT-FragEL染色检测心肌细胞凋亡。Annexin/7AAD双染法、直接免疫荧光标记法经流式细胞仪检测心肌细胞凋亡率及心肌细胞中caspase-3水平。结果:TGF-β1刺激24 h后,心肌细胞β-MHC mRNA水平明显高于对照组(P<0.01);PI染色结果TGF-β1组RNA含量明显增高,并呈剂量依赖性(P<0.01)。TdT-FragEL染色观察,TGF-β1可增加心肌细胞凋亡率(P<0.01)。与对照组相比,TGF-β1可明显上调心肌细胞中caspase-3(P<0.01);TGF-β1诱导的心肌细胞凋亡率增加(P<0.01)。透射电镜观察TGF-β1可诱导心肌细胞肥大和凋亡。结论:TGF-β1可同时诱导心肌细胞肥大和凋亡,诱导凋亡可能与caspase-3有关。
