OBJECTIVE To investigate the mechanism of SIRT1/AMPK signaling pathway between hepatocytes and hepatic stellate cells(HSCs).METHODS Normal human Chang liver cells and human hepatic stellate cell line,LX-2 cells were t...OBJECTIVE To investigate the mechanism of SIRT1/AMPK signaling pathway between hepatocytes and hepatic stellate cells(HSCs).METHODS Normal human Chang liver cells and human hepatic stellate cell line,LX-2 cells were treated with SRT1720(10μmol·L^(-1))and AICAR(500μmol·L^(-1))prior to ethanol(50 mmol·L^(-1)) for 24 and 48 h.Cell viability was analyzed by methyl thiazolyl tetrazolium assay.SIRT1,AMPK and p-AMPK m RNA levels for 24 h and 48 h were analyzed by RT-PCR,SIRT1,AMPK and p-AMPK protein expressions in the supernatant at 24 and 48 h was detected by Western blot.RESULTS SRT1720 and AICAR effectively decreased LX-2 cell viabilities and exhibited scarcely little toxicity in human Chang liver cells.SRT1720 and AICAR attenuated collagen-I,α-smooth muscle actin(α-SMA)levels,activated liver kinase B-1(LKB1)and AMPK phosphorylation in ethanol treated LX-2 cells.Meanwhile,SRT1720 and AICAR enhanced SIRT1 expression mediated by ethanol both in Chang liver cells and LX-2 cells.Furthermore,SRT1720 and AICAR suppressed the expression of sterol regulatory element-binding protein-1(SREBP-1)to regulate fatty acid synthesis.CONCLUSION SIRT1 agonist and AMPK agonist blocked the crosstalk between hepatocytes and HSCs via SIRT1/AMPK signaling pathway to modulate hepatocytes accumulation of lipid and HSCs activation.展开更多
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
The aim of the study was to investigate the hepatoprotective effects of Folium syringae(FS) extracts against ethanolinduced acute liver injury. Mice and primary hepatocytes were pretreated with FS extracts at differen...The aim of the study was to investigate the hepatoprotective effects of Folium syringae(FS) extracts against ethanolinduced acute liver injury. Mice and primary hepatocytes were pretreated with FS extracts at different dosages before ethanol administration. Transaminases, glutathione S-transferase A1 level and hepatic biochemical indices(malondialdehyde, superoxide dismutase, glutathione and glutathione peroxidase) were determined. Pretreatment with FS extracts significantly inhibited the damage caused by ethanol and the hepatoprotective effects of FS were almost similar to Silymarin that was used to treat alcoholic liver injury. GSTA1 contents in all the FS extract-treated groups were significantly different from those in the ethanol-induced acute liver injury model group(p<0.01), and similar trends were observed in transaminases and hepatic indices level both in vitro and in vivo. The results showed that FS extracts had hepatoprotective effects against ethanol-induced injury. Those effects might be related to the enhancement of antioxidant capacity of liver cells, and FS extracts could reduce the release of liver GSTA1, which contributed to improve liver detoxification.展开更多
Recent progresses in 2018–2019 from space experiments onboard SJ-10 recoverable satellite and on parabolic flight were summarized,mainly focusing on cell mechano-biological coupling under microgravity.In the meantime...Recent progresses in 2018–2019 from space experiments onboard SJ-10 recoverable satellite and on parabolic flight were summarized,mainly focusing on cell mechano-biological coupling under microgravity.In the meantime,technical pre-research and experimental system design for the biomechanics research platform on China Space Station was carried out and updated.展开更多
基金supported by National Natural Science Foundation of China(81700523)
文摘OBJECTIVE To investigate the mechanism of SIRT1/AMPK signaling pathway between hepatocytes and hepatic stellate cells(HSCs).METHODS Normal human Chang liver cells and human hepatic stellate cell line,LX-2 cells were treated with SRT1720(10μmol·L^(-1))and AICAR(500μmol·L^(-1))prior to ethanol(50 mmol·L^(-1)) for 24 and 48 h.Cell viability was analyzed by methyl thiazolyl tetrazolium assay.SIRT1,AMPK and p-AMPK m RNA levels for 24 h and 48 h were analyzed by RT-PCR,SIRT1,AMPK and p-AMPK protein expressions in the supernatant at 24 and 48 h was detected by Western blot.RESULTS SRT1720 and AICAR effectively decreased LX-2 cell viabilities and exhibited scarcely little toxicity in human Chang liver cells.SRT1720 and AICAR attenuated collagen-I,α-smooth muscle actin(α-SMA)levels,activated liver kinase B-1(LKB1)and AMPK phosphorylation in ethanol treated LX-2 cells.Meanwhile,SRT1720 and AICAR enhanced SIRT1 expression mediated by ethanol both in Chang liver cells and LX-2 cells.Furthermore,SRT1720 and AICAR suppressed the expression of sterol regulatory element-binding protein-1(SREBP-1)to regulate fatty acid synthesis.CONCLUSION SIRT1 agonist and AMPK agonist blocked the crosstalk between hepatocytes and HSCs via SIRT1/AMPK signaling pathway to modulate hepatocytes accumulation of lipid and HSCs activation.
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.
基金Supported by the National Natural Science Foundation of China(31472241)the Application Technology Research and Development Projects in Heilongjiang Province of China(PC13S03)
文摘The aim of the study was to investigate the hepatoprotective effects of Folium syringae(FS) extracts against ethanolinduced acute liver injury. Mice and primary hepatocytes were pretreated with FS extracts at different dosages before ethanol administration. Transaminases, glutathione S-transferase A1 level and hepatic biochemical indices(malondialdehyde, superoxide dismutase, glutathione and glutathione peroxidase) were determined. Pretreatment with FS extracts significantly inhibited the damage caused by ethanol and the hepatoprotective effects of FS were almost similar to Silymarin that was used to treat alcoholic liver injury. GSTA1 contents in all the FS extract-treated groups were significantly different from those in the ethanol-induced acute liver injury model group(p<0.01), and similar trends were observed in transaminases and hepatic indices level both in vitro and in vivo. The results showed that FS extracts had hepatoprotective effects against ethanol-induced injury. Those effects might be related to the enhancement of antioxidant capacity of liver cells, and FS extracts could reduce the release of liver GSTA1, which contributed to improve liver detoxification.
基金Supported by Strategic Priority Research Program and Frontier Science Key Project of Chinese Academy of Sciences(XDA04020202-17,XDA04020416,XDA15014100QYZDJSSW-JSC018),National Natural Science Foundation of China(U1738115)。
文摘Recent progresses in 2018–2019 from space experiments onboard SJ-10 recoverable satellite and on parabolic flight were summarized,mainly focusing on cell mechano-biological coupling under microgravity.In the meantime,technical pre-research and experimental system design for the biomechanics research platform on China Space Station was carried out and updated.
