Soy glycinin derived octapeptide(SGP8)is a peptide obtained from degradation of the soy glycinin,whose amino acid sequence is IAVPGEVA.To determine the effect of SGP8 on non-alcoholic fatty liver disease(NAFLD),steato...Soy glycinin derived octapeptide(SGP8)is a peptide obtained from degradation of the soy glycinin,whose amino acid sequence is IAVPGEVA.To determine the effect of SGP8 on non-alcoholic fatty liver disease(NAFLD),steatosis Hep G2 cells were induced by 1 mmol/L free fatty acid(FFA)and C57 BL/6 J mice were fed with methionine-choline defi cient(MCD)diet for 3 weeks to establish NAFLD model.The results of oil red O staining and total cholesterol(TC)/triglyceride(TG)contents showed that SGP8 could signifi cantly reduce the lipid content of steatosis Hep G2 cells.In vivo,SGP8 lowered plasma alanine aminotransferase(ALT)and low density lipoprotein(LDL)content,normalized hepatic superoxide dismutase(SOD)and malondialdehyde(MDA)production,and reduced the severity of liver infl ammation.The results of Western blotting showed that SGP8 increased expression of Sirtuin-1(SIRT1)and phosphorylation level of AMP activated protein kinase(AMPK)in hepatocytes.Through activation of SIRT1/AMPK pathway,SGP8 downregulated the expression of sterol regulatory element binding protein 1 c(SREBP-1 c)and its target genes ACC and FAS expression levels,and increased the phosphorylation level of acetyl Co A carboxylase(ACC).Furthermore,SGP8 also upregulated the expression of transcription factor peroxisome proliferator activated receptorα(PPARα),which was regulated by SIRT1/AMPK pathway,and its target gene CPT1 level.In conclusion,SGP8 might improve NAFLD by activating the SIRT1/AMPK pathway.Our data suggest that SGP8 may act as a novel and potent therapeutic agent against NAFLD.展开更多
AIM: To characterize how insulin-like growth factor 2 (IGF2) mRNA binding protein p62/IMP2-2 promotes steatohepatitis in the absence of dietary cholesterol.
AIM To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis(NASH) development in mice fed a methionine-choline-deficient(MCD) diet. METHODS Twenty-four male C57 BL/6 J mice were equ...AIM To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis(NASH) development in mice fed a methionine-choline-deficient(MCD) diet. METHODS Twenty-four male C57 BL/6 J mice were equally divided into four groups and fed a methionine-choline-sufficient diet for 2 wk(Control 2 w group,n = 6) or 4 wk(Control 4 w group,n = 6) or the MCD diet for 2 wk(MCD 2 w group,n = 6) or 4 wk(MCD 4 w group,n = 6). Liver injury,fibrosis,and intestinal barrier function were evaluated after 2 and 4 wk of feeding. The fecal microbiome and metabolome were studied using 16 s r RNA deep sequencing and gas chromatography-mass spectrometry. RESULTS The mice fed the MCD diet presented with simple hepatic steatosis and slight intestinal barrier deterioration after 2 wk. After 4 wk of feeding with the MCD diet,however,the mice developed prominent NASH with liver fibrosis,and the intestinal barrier was more impaired. Compared with the control diet,the MCD diet induced gradual gut microbiota dysbiosis,as evidenced by a marked decrease in the abundance of Alistipes and the(Eubacterium) coprostanoligenes group(P < 0.001 and P < 0.05,respectively) and a significant increase in Ruminococcaceae UCG 014 abundance(P < 0.05) after 2 wk. At 4 wk,the MCD diet significantly reduced the promising probiotic Bifidobacterium levels and markedly promoted Bacteroides abundance(P < 0.05,and P < 0.01,respectively). The fecal metabolomic profile was also substantially altered by the MCD diet: At 2 wk,arachidic acid,hexadecane,palmitic acid,and tetracosane were selected as potential biomarkers that were significantly different in the corresponding control group,and at 4 wk,cholic acid,cholesterol,arachidic acid,tetracosane,and stearic acid were selected. CONCLUSION The MCD diet induced persistent alterations in the gut microbiota and metabolome.展开更多
Metabolic-associated fatty liver disease(MAFLD),which is previously known as non-alcoholic fatty liver disease(NAFLD),represents a major health concern worldwide with limited therapy.Here,we provide evidence that ferr...Metabolic-associated fatty liver disease(MAFLD),which is previously known as non-alcoholic fatty liver disease(NAFLD),represents a major health concern worldwide with limited therapy.Here,we provide evidence that ferroptosis,a novel form of regulated cell death characterized by iron-driven lipid peroxidation,was comprehensively activated in liver tissues from MAFLD patients.The canonical-GPX4(cGPX4),which is the most important negative controller of ferroptosis,is downregulated at protein but not mRNA level.Interestingly,a non-canonical GPX4 transcript-variant is induced(inducible-GPX4,iGPX4)in MAFLD condition.The high fat-fructose/sucrose diet(HFFD)and methionine/choline-deficient diet(MCD)-induced MAFLD pathologies,including hepatocellular ballooning,steatohepatitis andfibrosis,were attenuated and aggravated,respectively,in cGPX4-and iGPX4-knockin mice.cGPX4 and iGPX4 isoforms also displayed opposing effects on oxidative stress and ferroptosis in hepatocytes.Knockdown of iGPX4 by siRNA alleviated lipid stress,ferroptosis and cell injury.Mechanistically,the triggered iGPX4 interacts with cGPX4 to facilitate the transformation of cGPX4 from enzymatic-active monomer to enzymatic-inactive oligomers upon lipid stress,and thus promotes ferroptosis.Co-immunoprecipitation and nano LC–MS/MS analyses confirmed the interaction between iGPX4 and cGPX4.Our results reveal a detrimental role of non-canonical GPX4 isoform in ferroptosis,and indicate selectively targeting iGPX4 may be a promising therapeutic strategy for MAFLD.展开更多
BACKGROUND: Worldwide, about 25% of individuals with chronic hepatitis B have fatty liver disease. Lipogenic diets that are completely devoid of methionine and choline induce nonalcoholic fatty liver disease. However,...BACKGROUND: Worldwide, about 25% of individuals with chronic hepatitis B have fatty liver disease. Lipogenic diets that are completely devoid of methionine and choline induce nonalcoholic fatty liver disease. However, no animal model of nonalcoholic steatohepatitis associated with HBV infection is available, and the influence of viral infection on nutritional hepatic steatosis is unclear. METHODS: We used HBV surface antigen transgenic mice (HBs-Tg mice), which mimic healthy human carriers with hepatitis B surface antigen. The mice were fed with a high-fat methionine-choline-deficient diet (MCD) to build a reliable rodent nutritional model of nonalcoholic steatohepatitis associated with HBV infection, and the changes in body weight and serum triglycerides were measured. Hepatocyte ballooning changes were determined by hematoxylin and eosin staining. The extent of hepatic fat accumulation was evaluated by oil red O staining. Immunohistochemical assays were performed to detect proliferating cell nuclear antigen as an index of cell proliferation. RESULTS: MCD feeding provoked systemic weight loss and liver injury. MCD feeding caused more macrovesicular fat droplets and fat accumulation in the livers of HBs-Tg mice than in wild-type C57BL/6 mice. In addition, within 30 days of MCD exposure, more PCNA-positive nuclei were found in the livers of HBs-Tg mice. CONCLUSIONS: HBs-Tg mice fed with a lipogenic MCD form more macrovesicular fat droplets earlier, coincident with more hepatocyte proliferation, resulting in the appearance of increased susceptibility to experimental steatohepatitis in these mice.展开更多
Nonalcoholic steatohepatitis（NASH） is one of the most common liver diseases and a major cause of liver fibrosis worldwide.r-Aminobutyric acid（GABA） is one of the most abundant inhibitory neurotransmitters in the c...Nonalcoholic steatohepatitis（NASH） is one of the most common liver diseases and a major cause of liver fibrosis worldwide.r-Aminobutyric acid（GABA） is one of the most abundant inhibitory neurotransmitters in the central nervous system.Recently,it has been reported that GABAergic signaling pathways are found in various non-neuronal tissues including the immune system and play a functional role.In the present study,we investigated whether administration of GABA has effects on NASH through its immunomodulatory effects.To test this hypothesis,C57BL/6 mice were fed a methionine-choline-deficient（MCD） diet for 8 weeks.After four weeks into MCD feeding,mice were provided with plain water（control） or water containing 2 mg/mL of GABA for the subsequent 4 weeks.Using this MCD diet-induced NASH model,we found that mice receiving GABA showed more severe steatohepatitis and liver fibrosis than control mice.This increased liver damage was confirmed by higher levels of serum alanine transaminase（ALT） and aspartate aminotransferase（AST） compared to the control group.In accordance with increased liver steatohepatitis,NASH-related and inflammatory gene expression（collagen al,tissue inhibitor of metalloproteinase-1,TNF-α） in the liver was markedly increased in GABA-treated mice.Furthermore,GABA directly enhanced production of inflammatory cytokines including IL-6 and TNF-α in LPS activated RAW macrophage cells and increased TIB-73 hepatocyte death.Such effects were abolished when GABA was treated with bicuculline,a competitive antagonist of GABA receptors.These results suggest that oral administration of GABA may be involved in changes of the liver immune milieu and conferred detrimental effects on NASH progression.展开更多
基金funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Soy glycinin derived octapeptide(SGP8)is a peptide obtained from degradation of the soy glycinin,whose amino acid sequence is IAVPGEVA.To determine the effect of SGP8 on non-alcoholic fatty liver disease(NAFLD),steatosis Hep G2 cells were induced by 1 mmol/L free fatty acid(FFA)and C57 BL/6 J mice were fed with methionine-choline defi cient(MCD)diet for 3 weeks to establish NAFLD model.The results of oil red O staining and total cholesterol(TC)/triglyceride(TG)contents showed that SGP8 could signifi cantly reduce the lipid content of steatosis Hep G2 cells.In vivo,SGP8 lowered plasma alanine aminotransferase(ALT)and low density lipoprotein(LDL)content,normalized hepatic superoxide dismutase(SOD)and malondialdehyde(MDA)production,and reduced the severity of liver infl ammation.The results of Western blotting showed that SGP8 increased expression of Sirtuin-1(SIRT1)and phosphorylation level of AMP activated protein kinase(AMPK)in hepatocytes.Through activation of SIRT1/AMPK pathway,SGP8 downregulated the expression of sterol regulatory element binding protein 1 c(SREBP-1 c)and its target genes ACC and FAS expression levels,and increased the phosphorylation level of acetyl Co A carboxylase(ACC).Furthermore,SGP8 also upregulated the expression of transcription factor peroxisome proliferator activated receptorα(PPARα),which was regulated by SIRT1/AMPK pathway,and its target gene CPT1 level.In conclusion,SGP8 might improve NAFLD by activating the SIRT1/AMPK pathway.Our data suggest that SGP8 may act as a novel and potent therapeutic agent against NAFLD.
基金Supported by An EASL Sheila Sherlock fellowshipa Bank Austria visiting scientist program fellowship(to Kessler SM)
文摘AIM: To characterize how insulin-like growth factor 2 (IGF2) mRNA binding protein p62/IMP2-2 promotes steatohepatitis in the absence of dietary cholesterol.
基金the National Natural Science Foundation of China,No.81330011,No.81790631,and No.81790633the Science Fund for Creative Research Groups of the National Natural Science Foundation of China,No.81721091the National Basic Research Program of China(973 program),No.2013CB531401
文摘AIM To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis(NASH) development in mice fed a methionine-choline-deficient(MCD) diet. METHODS Twenty-four male C57 BL/6 J mice were equally divided into four groups and fed a methionine-choline-sufficient diet for 2 wk(Control 2 w group,n = 6) or 4 wk(Control 4 w group,n = 6) or the MCD diet for 2 wk(MCD 2 w group,n = 6) or 4 wk(MCD 4 w group,n = 6). Liver injury,fibrosis,and intestinal barrier function were evaluated after 2 and 4 wk of feeding. The fecal microbiome and metabolome were studied using 16 s r RNA deep sequencing and gas chromatography-mass spectrometry. RESULTS The mice fed the MCD diet presented with simple hepatic steatosis and slight intestinal barrier deterioration after 2 wk. After 4 wk of feeding with the MCD diet,however,the mice developed prominent NASH with liver fibrosis,and the intestinal barrier was more impaired. Compared with the control diet,the MCD diet induced gradual gut microbiota dysbiosis,as evidenced by a marked decrease in the abundance of Alistipes and the(Eubacterium) coprostanoligenes group(P < 0.001 and P < 0.05,respectively) and a significant increase in Ruminococcaceae UCG 014 abundance(P < 0.05) after 2 wk. At 4 wk,the MCD diet significantly reduced the promising probiotic Bifidobacterium levels and markedly promoted Bacteroides abundance(P < 0.05,and P < 0.01,respectively). The fecal metabolomic profile was also substantially altered by the MCD diet: At 2 wk,arachidic acid,hexadecane,palmitic acid,and tetracosane were selected as potential biomarkers that were significantly different in the corresponding control group,and at 4 wk,cholic acid,cholesterol,arachidic acid,tetracosane,and stearic acid were selected. CONCLUSION The MCD diet induced persistent alterations in the gut microbiota and metabolome.
基金supported by the grants from National Natural Science Foundation of China (82073915, 91849135, 81673485, 81773719, 81973312 and 81971306)National Key Research and Development Project (2018YFA0108301, China)+2 种基金Shanghai Science and Technology Commission Experimental Animal Grants (21XD1424900, 19140904700, 19140904900 and 21S11901200, China)Shanghai Shuguang Program (19SG32, China)Shanghai “Rising Stars of Medical Talent” Youth Development ProgramYouth Medical Talents-Clinical Pharmacist Program [SHWRS(2020)_087, China]
文摘Metabolic-associated fatty liver disease(MAFLD),which is previously known as non-alcoholic fatty liver disease(NAFLD),represents a major health concern worldwide with limited therapy.Here,we provide evidence that ferroptosis,a novel form of regulated cell death characterized by iron-driven lipid peroxidation,was comprehensively activated in liver tissues from MAFLD patients.The canonical-GPX4(cGPX4),which is the most important negative controller of ferroptosis,is downregulated at protein but not mRNA level.Interestingly,a non-canonical GPX4 transcript-variant is induced(inducible-GPX4,iGPX4)in MAFLD condition.The high fat-fructose/sucrose diet(HFFD)and methionine/choline-deficient diet(MCD)-induced MAFLD pathologies,including hepatocellular ballooning,steatohepatitis andfibrosis,were attenuated and aggravated,respectively,in cGPX4-and iGPX4-knockin mice.cGPX4 and iGPX4 isoforms also displayed opposing effects on oxidative stress and ferroptosis in hepatocytes.Knockdown of iGPX4 by siRNA alleviated lipid stress,ferroptosis and cell injury.Mechanistically,the triggered iGPX4 interacts with cGPX4 to facilitate the transformation of cGPX4 from enzymatic-active monomer to enzymatic-inactive oligomers upon lipid stress,and thus promotes ferroptosis.Co-immunoprecipitation and nano LC–MS/MS analyses confirmed the interaction between iGPX4 and cGPX4.Our results reveal a detrimental role of non-canonical GPX4 isoform in ferroptosis,and indicate selectively targeting iGPX4 may be a promising therapeutic strategy for MAFLD.
基金supported by grants from the National Natural Science Foundation of China (30730084 and 30721002)the National Key Basic Research Program of China (973 Program) (2009CB522403,2007CB512405,and 2007CB512807)
文摘BACKGROUND: Worldwide, about 25% of individuals with chronic hepatitis B have fatty liver disease. Lipogenic diets that are completely devoid of methionine and choline induce nonalcoholic fatty liver disease. However, no animal model of nonalcoholic steatohepatitis associated with HBV infection is available, and the influence of viral infection on nutritional hepatic steatosis is unclear. METHODS: We used HBV surface antigen transgenic mice (HBs-Tg mice), which mimic healthy human carriers with hepatitis B surface antigen. The mice were fed with a high-fat methionine-choline-deficient diet (MCD) to build a reliable rodent nutritional model of nonalcoholic steatohepatitis associated with HBV infection, and the changes in body weight and serum triglycerides were measured. Hepatocyte ballooning changes were determined by hematoxylin and eosin staining. The extent of hepatic fat accumulation was evaluated by oil red O staining. Immunohistochemical assays were performed to detect proliferating cell nuclear antigen as an index of cell proliferation. RESULTS: MCD feeding provoked systemic weight loss and liver injury. MCD feeding caused more macrovesicular fat droplets and fat accumulation in the livers of HBs-Tg mice than in wild-type C57BL/6 mice. In addition, within 30 days of MCD exposure, more PCNA-positive nuclei were found in the livers of HBs-Tg mice. CONCLUSIONS: HBs-Tg mice fed with a lipogenic MCD form more macrovesicular fat droplets earlier, coincident with more hepatocyte proliferation, resulting in the appearance of increased susceptibility to experimental steatohepatitis in these mice.
基金supported by the National Research Foundation of Korea Grant funded by the Korean Government(No.2008-0061604)supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF),whichis funded by the Ministry of Science,ICT & Future Planning 18(2014R1A1A1006622)
文摘Nonalcoholic steatohepatitis（NASH） is one of the most common liver diseases and a major cause of liver fibrosis worldwide.r-Aminobutyric acid（GABA） is one of the most abundant inhibitory neurotransmitters in the central nervous system.Recently,it has been reported that GABAergic signaling pathways are found in various non-neuronal tissues including the immune system and play a functional role.In the present study,we investigated whether administration of GABA has effects on NASH through its immunomodulatory effects.To test this hypothesis,C57BL/6 mice were fed a methionine-choline-deficient（MCD） diet for 8 weeks.After four weeks into MCD feeding,mice were provided with plain water（control） or water containing 2 mg/mL of GABA for the subsequent 4 weeks.Using this MCD diet-induced NASH model,we found that mice receiving GABA showed more severe steatohepatitis and liver fibrosis than control mice.This increased liver damage was confirmed by higher levels of serum alanine transaminase（ALT） and aspartate aminotransferase（AST） compared to the control group.In accordance with increased liver steatohepatitis,NASH-related and inflammatory gene expression（collagen al,tissue inhibitor of metalloproteinase-1,TNF-α） in the liver was markedly increased in GABA-treated mice.Furthermore,GABA directly enhanced production of inflammatory cytokines including IL-6 and TNF-α in LPS activated RAW macrophage cells and increased TIB-73 hepatocyte death.Such effects were abolished when GABA was treated with bicuculline,a competitive antagonist of GABA receptors.These results suggest that oral administration of GABA may be involved in changes of the liver immune milieu and conferred detrimental effects on NASH progression.
