BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple b...BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rate,and GSDMD expression,restoring SLC7A11 depletion.Moreover,SIRT1 agonist and overexpression of SIRT1 alleviated acute liver injury and decreased iron deposition compared with results in the model group,accompanied by reduced p53,GSDMD,and ACSL4,and increased SLC7A11 and GPX4.Inactivation of SIRT1 exacerbated ferroptotic and pyroptotic cell death and aggravated liver injury in LPS/D-GalNinduced in vitro and in vivo models.CONCLUSION SIRT1 activation attenuates LPS/D-GalN-induced ferroptosis and pyroptosis by inhibiting the p53/GPX4/GSDMD signaling pathway in ALF.展开更多
In the peripheral nervous system,the activation of Sirtuin 1 can improve insulin resistance;however,the role played by Sirtuin 1 in the central nervous system remains unknown.In this study,rat models of diabetes melli...In the peripheral nervous system,the activation of Sirtuin 1 can improve insulin resistance;however,the role played by Sirtuin 1 in the central nervous system remains unknown.In this study,rat models of diabetes mellitus were generated by a single injection of streptozotocin.At 8 weeks after streptozotocin injection,the Morris water maze test and western blot assays confirmed that the diabetic model rats had learning and memory deficits,insulin resistance,and Sirtuin 1 expression could be detected in the hippocampus.Insulin and the insulin receptor inhibitor S961 were intranasally administered to investigate the regulatory effects of insulin signaling on Sirtuin 1.The results showed that insulin administration improved the impaired cognitive function of diabetic model rats and increased the expression levels of phosphorylated insulin receptor,phosphorylated insulin receptor substrate 1,and Sirtuin 1 in the hippocampus.Conversely,S961 administration resulted in more severe cognitive dysfunction and reduced the expression levels of phosphorylated insulin receptor,phosphorylated insulin receptor substrate 1,and Sirtuin 1.The Sirtuin 1 activator SRT2104 and the inhibitor Sirtinol were injected into the lateral ventricle,which revealed that the activation of Sirtuin 1 increased the expression levels of target of rapamycin complex 1,phosphorylated cAMP-response elementbinding protein,and brain-derived neurotrophic factor.Hippocampal dendritic length and spine density also increased in response to Sirtuin 1 activation.In contrast,Sirtinol decreased the expression levels of target of rapamycin complex 1,phosphorylated cAMP-response elementbinding protein,and brain-derived neurotrophic factor and damaged the dendritic structure.These findings suggest that the Sirtuin 1 signaling pathway plays an important role in the development of insulin resistance-related cognitive deficits in diabetic rats.This study was approved by the Animal Ethics Welfare Committee of the First Affiliated Hospital of Hunan University of Chinese Medicine(approval No.ZYFY201811207)in November 2018.展开更多
BACKGROUND Sirtuin 1(SIRT1)is a nicotinamide adenine dinucleotide(NAD+)-dependent protein deacetylase that is involved in various diseases,including cancers,metabolic diseases,and inflammation-associated diseases.Howe...BACKGROUND Sirtuin 1(SIRT1)is a nicotinamide adenine dinucleotide(NAD+)-dependent protein deacetylase that is involved in various diseases,including cancers,metabolic diseases,and inflammation-associated diseases.However,the role of SIRT1 in ulcerative colitis(UC)is still confusing.AIM To investigate the role of SIRT1 in intestinal epithelial cells(IECs)in UC and further explore the underlying mechanisms.METHODS We developed a coculture model using macrophages and Caco-2 cells.After treatment with the SIRT1 activator SRT1720 or inhibitor nicotinamide(NAM),the expression of occludin and zona occludens 1(ZO-1)was assessed by Western blot analysis.Annexin V-APC/7-AAD assays were performed to evaluate Caco-2 apoptosis.Dextran sodium sulfate(DSS)-induced colitis mice were exposed to SRT1720 or NAM for 7 d.Transferase-mediated dUTP nick-end labeling(TUNEL)assays were conducted to assess apoptosis in colon tissues.The expression levels of glucose-regulated protein 78(GRP78),CCAAT/enhancerbinding protein homologous protein(CHOP),caspase-12,caspase-9,and caspase-3 in Caco-2 cells and the colon tissues of treated mice were examined by quantitative real-time PCR and Western blot.RESULTS SRT1720 treatment increased the protein levels of occludin and ZO-1 and inhibited Caco-2 apoptosis,whereas NAM administration caused the opposite effects.DSS-induced colitis mice treated with SRT1720 had a lower disease activity index(P<0.01),histological score(P<0.001),inflammatory cytokine levels(P<0.01),and apoptotic cell rate(P<0.01),while exposure to NAM caused the opposite effects.Moreover,SIRT1 activation reduced the expression levels of GRP78,CHOP,cleaved caspase-12,cleaved caspase-9,and cleaved caspase-3 in Caco-2 cells and the colon tissues of treated mice.CONCLUSION SIRT1 activation reduces apoptosis of IECs via the suppression of endoplasmic reticulum stress-mediated apoptosis-associated molecules CHOP and caspase-12.SIRT1 activation may be a potential therapeutic strategy for UC.展开更多
AIM:To investigate the possible involvement of Sirtuin1(SIRT1)in rat orthotopic liver transplantation(OLT),when Institute Georges Lopez 1(IGL-1)preservation solution is enriched with trimetazidine(TMZ).METHODS:Male Sp...AIM:To investigate the possible involvement of Sirtuin1(SIRT1)in rat orthotopic liver transplantation(OLT),when Institute Georges Lopez 1(IGL-1)preservation solution is enriched with trimetazidine(TMZ).METHODS:Male Sprague-Dawley rats were used as donors and recipients.Livers were stored in IGL-1 preservation solution for 8h at 4℃,and then underwent OLT according to Kamada’s cuff technique without arterialization.In another group,livers were stored in IGL-1 preservation solution supplemented with TMZ,at10-6 mol/L,for 8 h at 4℃and then underwent OLT.Rats were sacrificed 24 h after reperfusion,and liver and plasma samples were collected.Liver injury(transaminase levels),mitochondrial damage(glutamate dehydrogenase activity)oxidative stress(malondialdehyde levels),and nicotinamide adenine dinucleotide(NAD+),the cofactor necessary for SIRT1 activity,were determined by biochemical methods.SIRT1 and its substrates(acFox O1,ac-p53),the precursor of NAD+,nicotinamide phosphoribosyltransferase(NAMPT),as well as the phosphorylation of adenosine monophosphate activated protein kinase(AMPK),p-m TOR,p-p70S6K(direct substrate of m TOR),autophagy parameters(beclin-1,LC3B)and MAP kinases(p-p38 and p-ERK)were determined by Western blot.RESULTS:Liver grafts preserved in IGL-1 solution enriched with TMZ presented reduced liver injury and mitochondrial damage compared with those preservedin IGL-1 solution alone.In addition,livers preserved in IGL-1+TMZ presented reduced levels of oxidative stress.This was consistent with enhanced SIRT1 protein expression and elevated SIRT1 activity,as indicated by decreased acetylation of p53 and Fox O1.The elevated SIRT1 activity in presence of TMZ can be attributed to the enhanced NAMPT protein and NAD+/NADH levels.Up-regulation of SIRT1 was consistent with activation of AMPK and inhibition of phosphorylation of m TOR and its direct substrate(p-p70S6K).As a consequence,autophagy mediators(beclin-1 and LC3B)were overexpressed.Furthermore,MAP kinases were regulated in livers preserved with IGL-1+TMZ,as they were characterized by enhanced p-ERK and decreased p-p38protein expression.CONCLUSION:Our study shows that IGL-1 preservation solution enriched with TMZ protects liver grafts from the IRI associated with OLT,through SIRT1 up-regulation.展开更多
AIM: To investigate a possible association between losartan and sirtuin 1(SIRT1) in reduced-size orthotopic liver transplantation(ROLT) in rats.METHODS: Livers of male Sprague-Dawley rats(200-250 g) were preserved in ...AIM: To investigate a possible association between losartan and sirtuin 1(SIRT1) in reduced-size orthotopic liver transplantation(ROLT) in rats.METHODS: Livers of male Sprague-Dawley rats(200-250 g) were preserved in University of Wisconsin preservation solution for 1 h at 4 ℃ prior to ROLT.In an additional group,an antagonist of angiotensin Ⅱ type 1 receptor(AT1R),losartan,was orally administered(5 mg/kg) 24 h and 1 h before the surgical procedure to both the donors and the recipients.Transaminase(as an indicator of liver injury),SIRT1 activity,and nicotinamide adenine dinucleotide(NAD+,a co-factor necessary for SIRT1 activity) levels were determined by biochemical methods.Protein expression of SIRT1,acetylated Fox O1(ac-Fox O1),NAMPT(the precursor of NAD+),heat shock proteins(HSP70,HO-1) expression,endoplasmic reticulum stress(GRP78,IRE1 a,p-e IF2) and apoptosis(caspase 12 and caspase 3) parameters were determined by Western blot.Possible alterations in protein expression of mitogen activated protein kinases(MAPK),such as p-p38 and p-ERK,were also evaluated.Furthermore,the SIRT3 protein expression and m RNA levels were examined.RESULTS: The present study demonstrated that losartan administration led to diminished liver injury when compared to ROLT group,as evidenced by the significant decreases in alanine aminotransferase(358.3 ± 133.44 vs 206 ± 33.61,P < 0.05) and aspartate aminotransferase levels(893.57 ± 397.69 vs 500.85 ± 118.07,P < 0.05).The lessened hepatic injury in case of losartan was associated with enhanced SIRT1 protein expression and activity(5.27 ± 0.32 vs 6.08 ± 0.30,P < 0.05).This was concomitant with increased levels of NAD+(0.87 ± 0.22 vs 1.195 ± 0.144,P < 0.05) the co-factor necessary for SIRT1 activity,as well as with decreases in ac-Fox O1 expression.Losartan treatment also provoked significant attenuation of endoplasmic reticulum stress parameters(GRP78,IRE1 a,p-e IF2) which was consistent with reduced levels of both caspase 12 and caspase 3.Furthermore,losartan administration stimulated HSP70 protein expression and attenuated HO-1 expression.However,no changes were observed in protein or m RNA expression of SIRT3.Finally,the protein expression pattern of p-ERK and p-p38 were not altered upon losartan administration.CONCLUSION: The present study reports that losartan induces SIRT1 expression and activity,and that it reduces hepatic injury in a ROLT model.展开更多
Background:Mitochondria are dynamic organelles that constantly change their morphology through fission and fusion processes.Recently,abnormally increased mitochondrial fission has been observed in several types of can...Background:Mitochondria are dynamic organelles that constantly change their morphology through fission and fusion processes.Recently,abnormally increased mitochondrial fission has been observed in several types of can-cer.However,the functional roles of increased mitochondrial fission in lipid metabolism reprogramming in cancer cells remain unclear.This study aimed to explore the role of increased mitochondrial fission in lipid metabolism in hepa-tocellular carcinoma(HCC)cells.Methods:Lipid metabolism was determined by evaluating the changes in the expressions of core lipid metabolic enzymes and intracellular lipid content.The rate of fatty acid oxidation was evaluated by[PH]-labelled oleic acid.The mito-chondrial morphology in HCC cells was evaluated by fluorescent staining.The expression of protein was determined by real-time PCR,imnmunohistochemistry and Western blotting.Results:Activation of mitochondrial fission significantly promoted de novo fatty acid synthesis in HCC cells through upregulating the expression of lipogenic genes fatty acid synthase(FASN),acetyl-CoA carboxylasel(ACCI),and elonga-tion of very long chain fatty acid protein 6(ELOVL6),while suppressed fatty acid oxidation by downregulating carnitine palmitoyl transferase 1A(CPTIA)and acyl-CoA oxidase 1(ACOX1).Consistently,suppressed mitochondrial fission exhibited the opposite effects.Moreover,in vitro and in vivo studies revealed that mitochondrial fission-induced lipid metabolism reprogramming significantly promoted the proliferation and metastasis of HCC cells.Mechanistically,mito-chondrial fission increased the acetylation level of sterol regulatory element-binding protein 1(SREBPI)and peroxisome proliferator-activated receptor coaC-tivator 1 alpha(PGC-1a)by suppressing nicotinamide adenine dinucleotide(NAD+)/Sirtuin 1(SIRTI)signaling.The elevated SREBP1 then upregulated the expression of FASN,ACC1 and ELOVL6 in HCC cells,while PGC-1c/PPARa sup-pressed the expression of CPTIA and ACOXL Conclusions:Increased mitochondrial fission plays a crucial role in the repro-gramming of lipid metabolism in HCC cells,which provides strong evidence for the use of this process as a drug target in the treatment of this malignancy.展开更多
基金Supported by National Natural Science Foundation of China,No.82060123Doctoral Start-up Fund of Affiliated Hospital of Guizhou Medical University,No.gysybsky-2021-28+1 种基金Fund Project of Guizhou Provincial Science and Technology Department,No.[2020]1Y299Guizhou Provincial Health Commission,No.gzwjk2019-1-082。
文摘BACKGROUND Acute liver failure(ALF)has a high mortality with widespread hepatocyte death involving ferroptosis and pyroptosis.The silent information regulator sirtuin 1(SIRT1)-mediated deacetylation affects multiple biological processes,including cellular senescence,apoptosis,sugar and lipid metabolism,oxidative stress,and inflammation.AIM To investigate the association between ferroptosis and pyroptosis and the upstream regulatory mechanisms.METHODS This study included 30 patients with ALF and 30 healthy individuals who underwent serum alanine aminotransferase(ALT)and aspartate aminotransferase(AST)testing.C57BL/6 mice were also intraperitoneally pretreated with SIRT1,p53,or glutathione peroxidase 4(GPX4)inducers and inhibitors and injected with lipopolysaccharide(LPS)/D-galactosamine(D-GalN)to induce ALF.Gasdermin D(GSDMD)^(-/-)mice were used as an experimental group.Histological changes in liver tissue were monitored by hematoxylin and eosin staining.ALT,AST,glutathione,reactive oxygen species,and iron levels were measured using commercial kits.Ferroptosis-and pyroptosis-related protein and mRNA expression was detected by western blot and quantitative real-time polymerase chain reaction.SIRT1,p53,and GSDMD were assessed by immunofluorescence analysis.RESULTS Serum AST and ALT levels were elevated in patients with ALF.SIRT1,solute carrier family 7a member 11(SLC7A11),and GPX4 protein expression was decreased and acetylated p5,p53,GSDMD,and acyl-CoA synthetase long-chain family member 4(ACSL4)protein levels were elevated in human ALF liver tissue.In the p53 and ferroptosis inhibitor-treated and GSDMD^(-/-)groups,serum interleukin(IL)-1β,tumour necrosis factor alpha,IL-6,IL-2 and C-C motif ligand 2 levels were decreased and hepatic impairment was mitigated.In mice with GSDMD knockout,p53 was reduced,GPX4 was increased,and ferroptotic events(depletion of SLC7A11,elevation of ACSL4,and iron accumulation)were detected.In vitro,knockdown of p53 and overexpression of GPX4 reduced AST and ALT levels,the cytostatic rate,and GSDMD expression,restoring SLC7A11 depletion.Moreover,SIRT1 agonist and overexpression of SIRT1 alleviated acute liver injury and decreased iron deposition compared with results in the model group,accompanied by reduced p53,GSDMD,and ACSL4,and increased SLC7A11 and GPX4.Inactivation of SIRT1 exacerbated ferroptotic and pyroptotic cell death and aggravated liver injury in LPS/D-GalNinduced in vitro and in vivo models.CONCLUSION SIRT1 activation attenuates LPS/D-GalN-induced ferroptosis and pyroptosis by inhibiting the p53/GPX4/GSDMD signaling pathway in ALF.
基金This study was supported by the National Natural Science Foundation of China,No.81874464(to YHW)the Natural Science Foundation of Hunan Province of China,No.2019JJ50464(to HY)the Open Fund of the Domestic First-class Discipline Construction Project of Chinese Medicine of Hunan University of Chinese Medicine,No.2018ZYX46(to HY).
文摘In the peripheral nervous system,the activation of Sirtuin 1 can improve insulin resistance;however,the role played by Sirtuin 1 in the central nervous system remains unknown.In this study,rat models of diabetes mellitus were generated by a single injection of streptozotocin.At 8 weeks after streptozotocin injection,the Morris water maze test and western blot assays confirmed that the diabetic model rats had learning and memory deficits,insulin resistance,and Sirtuin 1 expression could be detected in the hippocampus.Insulin and the insulin receptor inhibitor S961 were intranasally administered to investigate the regulatory effects of insulin signaling on Sirtuin 1.The results showed that insulin administration improved the impaired cognitive function of diabetic model rats and increased the expression levels of phosphorylated insulin receptor,phosphorylated insulin receptor substrate 1,and Sirtuin 1 in the hippocampus.Conversely,S961 administration resulted in more severe cognitive dysfunction and reduced the expression levels of phosphorylated insulin receptor,phosphorylated insulin receptor substrate 1,and Sirtuin 1.The Sirtuin 1 activator SRT2104 and the inhibitor Sirtinol were injected into the lateral ventricle,which revealed that the activation of Sirtuin 1 increased the expression levels of target of rapamycin complex 1,phosphorylated cAMP-response elementbinding protein,and brain-derived neurotrophic factor.Hippocampal dendritic length and spine density also increased in response to Sirtuin 1 activation.In contrast,Sirtinol decreased the expression levels of target of rapamycin complex 1,phosphorylated cAMP-response elementbinding protein,and brain-derived neurotrophic factor and damaged the dendritic structure.These findings suggest that the Sirtuin 1 signaling pathway plays an important role in the development of insulin resistance-related cognitive deficits in diabetic rats.This study was approved by the Animal Ethics Welfare Committee of the First Affiliated Hospital of Hunan University of Chinese Medicine(approval No.ZYFY201811207)in November 2018.
基金Supported by the National Nature Science Foundation of China,No.81600414the Natural Science Foundation of Zhejiang Province,No.LQ16H030001Zhejiang TCM Science and Technology Project,No.2016ZA123 and No.2018ZA013
文摘BACKGROUND Sirtuin 1(SIRT1)is a nicotinamide adenine dinucleotide(NAD+)-dependent protein deacetylase that is involved in various diseases,including cancers,metabolic diseases,and inflammation-associated diseases.However,the role of SIRT1 in ulcerative colitis(UC)is still confusing.AIM To investigate the role of SIRT1 in intestinal epithelial cells(IECs)in UC and further explore the underlying mechanisms.METHODS We developed a coculture model using macrophages and Caco-2 cells.After treatment with the SIRT1 activator SRT1720 or inhibitor nicotinamide(NAM),the expression of occludin and zona occludens 1(ZO-1)was assessed by Western blot analysis.Annexin V-APC/7-AAD assays were performed to evaluate Caco-2 apoptosis.Dextran sodium sulfate(DSS)-induced colitis mice were exposed to SRT1720 or NAM for 7 d.Transferase-mediated dUTP nick-end labeling(TUNEL)assays were conducted to assess apoptosis in colon tissues.The expression levels of glucose-regulated protein 78(GRP78),CCAAT/enhancerbinding protein homologous protein(CHOP),caspase-12,caspase-9,and caspase-3 in Caco-2 cells and the colon tissues of treated mice were examined by quantitative real-time PCR and Western blot.RESULTS SRT1720 treatment increased the protein levels of occludin and ZO-1 and inhibited Caco-2 apoptosis,whereas NAM administration caused the opposite effects.DSS-induced colitis mice treated with SRT1720 had a lower disease activity index(P<0.01),histological score(P<0.001),inflammatory cytokine levels(P<0.01),and apoptotic cell rate(P<0.01),while exposure to NAM caused the opposite effects.Moreover,SIRT1 activation reduced the expression levels of GRP78,CHOP,cleaved caspase-12,cleaved caspase-9,and cleaved caspase-3 in Caco-2 cells and the colon tissues of treated mice.CONCLUSION SIRT1 activation reduces apoptosis of IECs via the suppression of endoplasmic reticulum stress-mediated apoptosis-associated molecules CHOP and caspase-12.SIRT1 activation may be a potential therapeutic strategy for UC.
基金Supported by Fondo de Investigaciones Sanitarias,No.FIS PI12/00519Eirini Pantazi is the recipient of a fellowship from AGAUR,No.2012FI_B00382,Generalitat de Catalunya,Barcelona,Catalonia,Spain
文摘AIM:To investigate the possible involvement of Sirtuin1(SIRT1)in rat orthotopic liver transplantation(OLT),when Institute Georges Lopez 1(IGL-1)preservation solution is enriched with trimetazidine(TMZ).METHODS:Male Sprague-Dawley rats were used as donors and recipients.Livers were stored in IGL-1 preservation solution for 8h at 4℃,and then underwent OLT according to Kamada’s cuff technique without arterialization.In another group,livers were stored in IGL-1 preservation solution supplemented with TMZ,at10-6 mol/L,for 8 h at 4℃and then underwent OLT.Rats were sacrificed 24 h after reperfusion,and liver and plasma samples were collected.Liver injury(transaminase levels),mitochondrial damage(glutamate dehydrogenase activity)oxidative stress(malondialdehyde levels),and nicotinamide adenine dinucleotide(NAD+),the cofactor necessary for SIRT1 activity,were determined by biochemical methods.SIRT1 and its substrates(acFox O1,ac-p53),the precursor of NAD+,nicotinamide phosphoribosyltransferase(NAMPT),as well as the phosphorylation of adenosine monophosphate activated protein kinase(AMPK),p-m TOR,p-p70S6K(direct substrate of m TOR),autophagy parameters(beclin-1,LC3B)and MAP kinases(p-p38 and p-ERK)were determined by Western blot.RESULTS:Liver grafts preserved in IGL-1 solution enriched with TMZ presented reduced liver injury and mitochondrial damage compared with those preservedin IGL-1 solution alone.In addition,livers preserved in IGL-1+TMZ presented reduced levels of oxidative stress.This was consistent with enhanced SIRT1 protein expression and elevated SIRT1 activity,as indicated by decreased acetylation of p53 and Fox O1.The elevated SIRT1 activity in presence of TMZ can be attributed to the enhanced NAMPT protein and NAD+/NADH levels.Up-regulation of SIRT1 was consistent with activation of AMPK and inhibition of phosphorylation of m TOR and its direct substrate(p-p70S6K).As a consequence,autophagy mediators(beclin-1 and LC3B)were overexpressed.Furthermore,MAP kinases were regulated in livers preserved with IGL-1+TMZ,as they were characterized by enhanced p-ERK and decreased p-p38protein expression.CONCLUSION:Our study shows that IGL-1 preservation solution enriched with TMZ protects liver grafts from the IRI associated with OLT,through SIRT1 up-regulation.
基金Supported by Grants from Fondo de Investigaciones Sanitarias,No.FIS PI12/00519fellowship from Agència de Gestiód’Ajuts Universitaris i de Recerca,No.2012FI_B00382Generalitat de Catalunya,Barcelona,Catalonia,Spain(to Pantazi E)
文摘AIM: To investigate a possible association between losartan and sirtuin 1(SIRT1) in reduced-size orthotopic liver transplantation(ROLT) in rats.METHODS: Livers of male Sprague-Dawley rats(200-250 g) were preserved in University of Wisconsin preservation solution for 1 h at 4 ℃ prior to ROLT.In an additional group,an antagonist of angiotensin Ⅱ type 1 receptor(AT1R),losartan,was orally administered(5 mg/kg) 24 h and 1 h before the surgical procedure to both the donors and the recipients.Transaminase(as an indicator of liver injury),SIRT1 activity,and nicotinamide adenine dinucleotide(NAD+,a co-factor necessary for SIRT1 activity) levels were determined by biochemical methods.Protein expression of SIRT1,acetylated Fox O1(ac-Fox O1),NAMPT(the precursor of NAD+),heat shock proteins(HSP70,HO-1) expression,endoplasmic reticulum stress(GRP78,IRE1 a,p-e IF2) and apoptosis(caspase 12 and caspase 3) parameters were determined by Western blot.Possible alterations in protein expression of mitogen activated protein kinases(MAPK),such as p-p38 and p-ERK,were also evaluated.Furthermore,the SIRT3 protein expression and m RNA levels were examined.RESULTS: The present study demonstrated that losartan administration led to diminished liver injury when compared to ROLT group,as evidenced by the significant decreases in alanine aminotransferase(358.3 ± 133.44 vs 206 ± 33.61,P < 0.05) and aspartate aminotransferase levels(893.57 ± 397.69 vs 500.85 ± 118.07,P < 0.05).The lessened hepatic injury in case of losartan was associated with enhanced SIRT1 protein expression and activity(5.27 ± 0.32 vs 6.08 ± 0.30,P < 0.05).This was concomitant with increased levels of NAD+(0.87 ± 0.22 vs 1.195 ± 0.144,P < 0.05) the co-factor necessary for SIRT1 activity,as well as with decreases in ac-Fox O1 expression.Losartan treatment also provoked significant attenuation of endoplasmic reticulum stress parameters(GRP78,IRE1 a,p-e IF2) which was consistent with reduced levels of both caspase 12 and caspase 3.Furthermore,losartan administration stimulated HSP70 protein expression and attenuated HO-1 expression.However,no changes were observed in protein or m RNA expression of SIRT3.Finally,the protein expression pattern of p-ERK and p-p38 were not altered upon losartan administration.CONCLUSION: The present study reports that losartan induces SIRT1 expression and activity,and that it reduces hepatic injury in a ROLT model.
基金supported by the National Natural Sci-ence Foundation of China(81772618),the Young Elite Scientist Sponsorship Program by CAST(2018QNRC001),and the State Key Laboratory of Cancer Biology Project(CBSKL2019ZZ26).
文摘Background:Mitochondria are dynamic organelles that constantly change their morphology through fission and fusion processes.Recently,abnormally increased mitochondrial fission has been observed in several types of can-cer.However,the functional roles of increased mitochondrial fission in lipid metabolism reprogramming in cancer cells remain unclear.This study aimed to explore the role of increased mitochondrial fission in lipid metabolism in hepa-tocellular carcinoma(HCC)cells.Methods:Lipid metabolism was determined by evaluating the changes in the expressions of core lipid metabolic enzymes and intracellular lipid content.The rate of fatty acid oxidation was evaluated by[PH]-labelled oleic acid.The mito-chondrial morphology in HCC cells was evaluated by fluorescent staining.The expression of protein was determined by real-time PCR,imnmunohistochemistry and Western blotting.Results:Activation of mitochondrial fission significantly promoted de novo fatty acid synthesis in HCC cells through upregulating the expression of lipogenic genes fatty acid synthase(FASN),acetyl-CoA carboxylasel(ACCI),and elonga-tion of very long chain fatty acid protein 6(ELOVL6),while suppressed fatty acid oxidation by downregulating carnitine palmitoyl transferase 1A(CPTIA)and acyl-CoA oxidase 1(ACOX1).Consistently,suppressed mitochondrial fission exhibited the opposite effects.Moreover,in vitro and in vivo studies revealed that mitochondrial fission-induced lipid metabolism reprogramming significantly promoted the proliferation and metastasis of HCC cells.Mechanistically,mito-chondrial fission increased the acetylation level of sterol regulatory element-binding protein 1(SREBPI)and peroxisome proliferator-activated receptor coaC-tivator 1 alpha(PGC-1a)by suppressing nicotinamide adenine dinucleotide(NAD+)/Sirtuin 1(SIRTI)signaling.The elevated SREBP1 then upregulated the expression of FASN,ACC1 and ELOVL6 in HCC cells,while PGC-1c/PPARa sup-pressed the expression of CPTIA and ACOXL Conclusions:Increased mitochondrial fission plays a crucial role in the repro-gramming of lipid metabolism in HCC cells,which provides strong evidence for the use of this process as a drug target in the treatment of this malignancy.
