目的:探讨温针灸对类风湿性关节炎(RA)大鼠关节滑膜组织沉默信息调节因子2相关酶1(SIRT 1)表达的影响,以及对核转录因子-κB(NF-κB)的调节作用,分析温针灸改善RA的机制。方法:SD大鼠50只(雌雄各半),随机分为正常组、模型组、抑制剂组...目的:探讨温针灸对类风湿性关节炎(RA)大鼠关节滑膜组织沉默信息调节因子2相关酶1(SIRT 1)表达的影响,以及对核转录因子-κB(NF-κB)的调节作用,分析温针灸改善RA的机制。方法:SD大鼠50只(雌雄各半),随机分为正常组、模型组、抑制剂组、温针灸组、抑制剂+温针灸组,每组10只,采用皮内注射牛Ⅱ型胶原接种诱发制备大鼠RA模型,共21d。温针灸组于造模第1天取"足三里""肾俞"和"悬钟"温针灸治疗,刺激量以大鼠耐受为度,1次/d,共21d。抑制剂组于造模第1、7、14、21天腹腔内注射SIRT 1抑制剂尼克酰胺溶液。抑制剂+温针灸组于造模同时给予SIRT 1抑制剂,温针灸治疗同温针灸组。所有大鼠采用排水法测肿胀关节部体积,放射免疫法检测血清炎性因子IL-1β、IL-6和IL-8含量,免疫印迹法检测膝关节滑膜组织SIRT 1和NF-κB p 65蛋白的表达。结果:与正常组相比,模型组大鼠关节肿胀明显,血清中炎性因子IL-1β、IL-6和IL-8含量较高,膝关节滑膜组织SIRT 1蛋白表达减少,NF-κB p 65蛋白表达增加(P<0.01)。与模型组相比,温针灸组大鼠关节肿胀改善明显,炎性因子IL-1β、IL-6和IL-8含量减少,SIRT 1蛋白表达升高,NF-κB p 65蛋白表达降低(P<0.05)。与温针灸组相比,抑制剂+温针灸组大鼠关节肿胀改善程度较差(P>0.05);血清中炎性因子IL-1β、IL-6和IL-8含量较高,膝关节滑膜组织SIRT 1蛋白表达减少,NF-κB p 65蛋白表达增加(P<0.05)。结论:温针灸能有效降低RA大鼠血清炎性因子,调节关节滑膜组织SIRT 1和NF-κB p 65表达,这可能是温针灸改善RA关节炎性损伤的机制之一。展开更多
Synaptic dysfunction and abnormal processing of amyloid precursor protein(APP) are early pathological features in Alzheimer’s disease(AD). Recently, noncoding RNAs such as micro RNAs(mi RNAs) and circular RNAs(circ R...Synaptic dysfunction and abnormal processing of amyloid precursor protein(APP) are early pathological features in Alzheimer’s disease(AD). Recently, noncoding RNAs such as micro RNAs(mi RNAs) and circular RNAs(circ RNAs) have been reported to contribute to the pathogenesis of AD. We found an age-dependent elevation of mi R-138 in APP/PS1(presenilin-1) mice. Mi R-138 inhibited the expression of ADAM10 [a disintegrin and metalloproteinase domain-containing protein 10], promoted amyloid beta(Ab) production, and induced synaptic and learning/memory deficits in APP/PS1 mice, while its suppression alleviated the AD-like phenotype in these mice. Overexpression of sirtuin 1(Sirt1), a target of mi R-138, ameliorated the mi R-138-induced inhibition of ADAM10 and elevation of Ab in vitro. The circ RNA HDAC9(circ HDAC9) was predicted to contain a mi R-138 binding site in several databases. Its expression was inversely correlated with mi R-138 in both Ab-oligomertreated N2 a cells and APP/PS1 mice, and it co-localized with mi R-138 in the cytoplasm of N2 a cells. Circ HDAC9 acted as a mi R-138 sponge, decreasing mi R-138 expression, and reversing the Sirt1 suppression and excessive Ab production induced by mi R-138 in vitro. Moreover,circ HDAC9 was decreased in the serum of both AD patients and individuals with mild cognitive impairment.These results suggest that the circ HDAC9/mi R-138/Sirt1 pathway mediates synaptic function and APP processing in AD, providing a potential therapeutic target for its treatment.展开更多
目的研究大黄酸对糖尿病大鼠肾组织沉默接合型信息调节因子2同源蛋白1(SIRT1)表达的影响,探讨大黄酸对糖尿病大鼠肾脏损伤的保护作用及可能机制。方法采用高糖高脂饮食联合链脲佐菌素(35 mg/kg体质量)诱导2型糖尿病大鼠模型,分为正常组...目的研究大黄酸对糖尿病大鼠肾组织沉默接合型信息调节因子2同源蛋白1(SIRT1)表达的影响,探讨大黄酸对糖尿病大鼠肾脏损伤的保护作用及可能机制。方法采用高糖高脂饮食联合链脲佐菌素(35 mg/kg体质量)诱导2型糖尿病大鼠模型,分为正常组,糖尿病组,低、中、高剂量(50、100、150 mg/kg)大黄酸治疗组及10 mg/kg吡格列酮对照组。灌胃给药,每日1次。16周末检测大鼠空腹血糖(FPG)、空腹胰岛素(FINS)、甘油三酯(TG)、总胆固醇(TC)、血肌酐(Scr)、24 h尿蛋白(24 h U-PRO);计算肾质量指数(KM/BM)、胰岛素抵抗指数;PAS染色光镜观察肾组织病理形态学的改变;病理图像分析系统分析平均肾小球面积(MGA)及平均肾小球体积(MGV);实时荧光定量PCR检测肾组织SIRT1 mRNA表达;Western blot法检测肾组织SIRT1蛋白表达。结果糖尿病大鼠肾组织SIRT1表达降低。与糖尿病组比较,各治疗组大鼠FPG、FINS、HOMA-IR、TG、TC、Scr、24 h U-PRO、肾质量指数、MGA、MGV显著降低,肾组织病理形态学明显改善;SIRT1 mRNA及蛋白表达显著增加;大黄酸高剂量组各指标改善较显著。相关性分析显示,SIRT1蛋白表达与24 h U-PRO、MGV呈显著负相关。结论糖尿病大鼠肾组织SIRT1表达降低,大黄酸可通过改善胰岛素抵抗和血脂紊乱,增加SIRT1的表达,改善糖尿病大鼠肾脏损害。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
Ischemia-reperfusion injury(IRI)remains an unresolved and complicated situation in clinical practice,especially in the case of organ transplantation.Several factors contribute to its complexity;the depletion of energy...Ischemia-reperfusion injury(IRI)remains an unresolved and complicated situation in clinical practice,especially in the case of organ transplantation.Several factors contribute to its complexity;the depletion of energy during ischemia and the induction of oxidative stress during reperfusion initiate a cascade of pathways that lead to cell death and finally to severe organ injury.Recently,the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases has gained increasing attention from researchers,due to their involvement in the modulation of a wide variety of cellular functions.There are seven mammalian sirtuins and,among them,the nuclear/cytoplasmic sirtuin 1(SIRT1)and the mitochondrial sirtuin 3(SIRT3)are ubiquitously expressed in many tissue types.Sirtuins are known to play major roles in protecting against cellular stress and in controlling metabolic pathways,which are key processes during IRI.In this review,we mainly focus on SIRT1 and SIRT3 and examine their role in modulating pathways against energy depletion during ischemia and their involvement in oxidative stress,apoptosis,microcirculatory stress and inflammation during reperfusion.We present evidence of the beneficial effects of sirtuins against IRI and emphasize the importance of developing new strategies by enhancing their action.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 cruc展开更多
BACKGROUND It is well known that nonalcoholic fatty liver disease(NAFLD)is associated with insulin resistance(IR).LB100,a serine/threonine protein phosphatase 2A(PP2A)inhibitor,is closely related to IR.However,there i...BACKGROUND It is well known that nonalcoholic fatty liver disease(NAFLD)is associated with insulin resistance(IR).LB100,a serine/threonine protein phosphatase 2A(PP2A)inhibitor,is closely related to IR.However,there is little data regarding its direct influence on NAFLD.AIM To elucidate the effect and underlying mechanism of LB100 in NAFLD.METHODS After 10 wk of high fat diet(HFD)feeding,male C57BL/6 mice were injected intraperitoneally with vehicle or LB100 for an additional 6 wk(three times a week).The L02 cell line was treated with LB100 and free fatty acids(FFAs)for 24 h.Hematoxylin and eosin and oil red O staining were performed for histological examination.Western blot analysis was used to detect the protein expression of Sirtuin 1(Sirt1),total and phosphorylated AMP-activated protein kinaseα(AMPKα),and the proteins involved in lipogenesis and fatty acid oxidation.The mRNA levels were determined by qPCR.Pharmacological inhibition of AMPK was performed to further examine the exact mechanism of LB100 in NAFLD.RESULTS LB100 significantly ameliorated HFD-induced obesity,hepatic lipid accumulation and hepatic injury in mice.In addition,LB100 significantly downregulated the protein levels of acetyl-CoA carboxylase,sterol regulatory element-binding protein 1 and its lipogenesis target genes,including stearoyl-CoA desaturase-1 and fatty acid synthase,and upregulated the levels of proteins involved in fatty acidβ-oxidation,such as peroxisome proliferator-activated receptorα(PPARα),peroxisome proliferator-activated receptor gamma coactivator-1α(PGC-1α),carnitine palmitoyltransferase 1α,acyl-CoA oxidase 1 and uncoupling protein 2,as well as the upstream mediators Sirt1 and AMPKαin the livers of HFD-fed mice.In vitro,LB100 alleviated FFA-induced lipid accumulation in L02 cells through the AMPK/Sirt1 signaling pathway.Further studies showed that the curative effect of LB100 on lipid accumulation was abolished by inhibiting AMPKαin L02 cells.CONCLUSION PP2A inhibition by LB100 significantly ameliorates hepatic 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 Med展开更多
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 rat展开更多
文摘目的:探讨温针灸对类风湿性关节炎(RA)大鼠关节滑膜组织沉默信息调节因子2相关酶1(SIRT 1)表达的影响,以及对核转录因子-κB(NF-κB)的调节作用,分析温针灸改善RA的机制。方法:SD大鼠50只(雌雄各半),随机分为正常组、模型组、抑制剂组、温针灸组、抑制剂+温针灸组,每组10只,采用皮内注射牛Ⅱ型胶原接种诱发制备大鼠RA模型,共21d。温针灸组于造模第1天取"足三里""肾俞"和"悬钟"温针灸治疗,刺激量以大鼠耐受为度,1次/d,共21d。抑制剂组于造模第1、7、14、21天腹腔内注射SIRT 1抑制剂尼克酰胺溶液。抑制剂+温针灸组于造模同时给予SIRT 1抑制剂,温针灸治疗同温针灸组。所有大鼠采用排水法测肿胀关节部体积,放射免疫法检测血清炎性因子IL-1β、IL-6和IL-8含量,免疫印迹法检测膝关节滑膜组织SIRT 1和NF-κB p 65蛋白的表达。结果:与正常组相比,模型组大鼠关节肿胀明显,血清中炎性因子IL-1β、IL-6和IL-8含量较高,膝关节滑膜组织SIRT 1蛋白表达减少,NF-κB p 65蛋白表达增加(P<0.01)。与模型组相比,温针灸组大鼠关节肿胀改善明显,炎性因子IL-1β、IL-6和IL-8含量减少,SIRT 1蛋白表达升高,NF-κB p 65蛋白表达降低(P<0.05)。与温针灸组相比,抑制剂+温针灸组大鼠关节肿胀改善程度较差(P>0.05);血清中炎性因子IL-1β、IL-6和IL-8含量较高,膝关节滑膜组织SIRT 1蛋白表达减少,NF-κB p 65蛋白表达增加(P<0.05)。结论:温针灸能有效降低RA大鼠血清炎性因子,调节关节滑膜组织SIRT 1和NF-κB p 65表达,这可能是温针灸改善RA关节炎性损伤的机制之一。
基金supported by the National Natural Science Foundation of China (81500925)
文摘Synaptic dysfunction and abnormal processing of amyloid precursor protein(APP) are early pathological features in Alzheimer’s disease(AD). Recently, noncoding RNAs such as micro RNAs(mi RNAs) and circular RNAs(circ RNAs) have been reported to contribute to the pathogenesis of AD. We found an age-dependent elevation of mi R-138 in APP/PS1(presenilin-1) mice. Mi R-138 inhibited the expression of ADAM10 [a disintegrin and metalloproteinase domain-containing protein 10], promoted amyloid beta(Ab) production, and induced synaptic and learning/memory deficits in APP/PS1 mice, while its suppression alleviated the AD-like phenotype in these mice. Overexpression of sirtuin 1(Sirt1), a target of mi R-138, ameliorated the mi R-138-induced inhibition of ADAM10 and elevation of Ab in vitro. The circ RNA HDAC9(circ HDAC9) was predicted to contain a mi R-138 binding site in several databases. Its expression was inversely correlated with mi R-138 in both Ab-oligomertreated N2 a cells and APP/PS1 mice, and it co-localized with mi R-138 in the cytoplasm of N2 a cells. Circ HDAC9 acted as a mi R-138 sponge, decreasing mi R-138 expression, and reversing the Sirt1 suppression and excessive Ab production induced by mi R-138 in vitro. Moreover,circ HDAC9 was decreased in the serum of both AD patients and individuals with mild cognitive impairment.These results suggest that the circ HDAC9/mi R-138/Sirt1 pathway mediates synaptic function and APP processing in AD, providing a potential therapeutic target for its treatment.
文摘目的研究大黄酸对糖尿病大鼠肾组织沉默接合型信息调节因子2同源蛋白1(SIRT1)表达的影响,探讨大黄酸对糖尿病大鼠肾脏损伤的保护作用及可能机制。方法采用高糖高脂饮食联合链脲佐菌素(35 mg/kg体质量)诱导2型糖尿病大鼠模型,分为正常组,糖尿病组,低、中、高剂量(50、100、150 mg/kg)大黄酸治疗组及10 mg/kg吡格列酮对照组。灌胃给药,每日1次。16周末检测大鼠空腹血糖(FPG)、空腹胰岛素(FINS)、甘油三酯(TG)、总胆固醇(TC)、血肌酐(Scr)、24 h尿蛋白(24 h U-PRO);计算肾质量指数(KM/BM)、胰岛素抵抗指数;PAS染色光镜观察肾组织病理形态学的改变;病理图像分析系统分析平均肾小球面积(MGA)及平均肾小球体积(MGV);实时荧光定量PCR检测肾组织SIRT1 mRNA表达;Western blot法检测肾组织SIRT1蛋白表达。结果糖尿病大鼠肾组织SIRT1表达降低。与糖尿病组比较,各治疗组大鼠FPG、FINS、HOMA-IR、TG、TC、Scr、24 h U-PRO、肾质量指数、MGA、MGV显著降低,肾组织病理形态学明显改善;SIRT1 mRNA及蛋白表达显著增加;大黄酸高剂量组各指标改善较显著。相关性分析显示,SIRT1蛋白表达与24 h U-PRO、MGV呈显著负相关。结论糖尿病大鼠肾组织SIRT1表达降低,大黄酸可通过改善胰岛素抵抗和血脂紊乱,增加SIRT1的表达,改善糖尿病大鼠肾脏损害。
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 AGAUR,No.2012FI_B00382,Generalitat de Catalunya,Barcelona,Spain,to Pantazi ECSIC for the development program to Bejaoui M,No.I-COOP0005The Fondo de Investigaciones Sanitarias,No.FIS PI12/00519
文摘Ischemia-reperfusion injury(IRI)remains an unresolved and complicated situation in clinical practice,especially in the case of organ transplantation.Several factors contribute to its complexity;the depletion of energy during ischemia and the induction of oxidative stress during reperfusion initiate a cascade of pathways that lead to cell death and finally to severe organ injury.Recently,the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases has gained increasing attention from researchers,due to their involvement in the modulation of a wide variety of cellular functions.There are seven mammalian sirtuins and,among them,the nuclear/cytoplasmic sirtuin 1(SIRT1)and the mitochondrial sirtuin 3(SIRT3)are ubiquitously expressed in many tissue types.Sirtuins are known to play major roles in protecting against cellular stress and in controlling metabolic pathways,which are key processes during IRI.In this review,we mainly focus on SIRT1 and SIRT3 and examine their role in modulating pathways against energy depletion during ischemia and their involvement in oxidative stress,apoptosis,microcirculatory stress and inflammation during reperfusion.We present evidence of the beneficial effects of sirtuins against IRI and emphasize the importance of developing new strategies by enhancing their action.
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 cruc
文摘BACKGROUND It is well known that nonalcoholic fatty liver disease(NAFLD)is associated with insulin resistance(IR).LB100,a serine/threonine protein phosphatase 2A(PP2A)inhibitor,is closely related to IR.However,there is little data regarding its direct influence on NAFLD.AIM To elucidate the effect and underlying mechanism of LB100 in NAFLD.METHODS After 10 wk of high fat diet(HFD)feeding,male C57BL/6 mice were injected intraperitoneally with vehicle or LB100 for an additional 6 wk(three times a week).The L02 cell line was treated with LB100 and free fatty acids(FFAs)for 24 h.Hematoxylin and eosin and oil red O staining were performed for histological examination.Western blot analysis was used to detect the protein expression of Sirtuin 1(Sirt1),total and phosphorylated AMP-activated protein kinaseα(AMPKα),and the proteins involved in lipogenesis and fatty acid oxidation.The mRNA levels were determined by qPCR.Pharmacological inhibition of AMPK was performed to further examine the exact mechanism of LB100 in NAFLD.RESULTS LB100 significantly ameliorated HFD-induced obesity,hepatic lipid accumulation and hepatic injury in mice.In addition,LB100 significantly downregulated the protein levels of acetyl-CoA carboxylase,sterol regulatory element-binding protein 1 and its lipogenesis target genes,including stearoyl-CoA desaturase-1 and fatty acid synthase,and upregulated the levels of proteins involved in fatty acidβ-oxidation,such as peroxisome proliferator-activated receptorα(PPARα),peroxisome proliferator-activated receptor gamma coactivator-1α(PGC-1α),carnitine palmitoyltransferase 1α,acyl-CoA oxidase 1 and uncoupling protein 2,as well as the upstream mediators Sirt1 and AMPKαin the livers of HFD-fed mice.In vitro,LB100 alleviated FFA-induced lipid accumulation in L02 cells through the AMPK/Sirt1 signaling pathway.Further studies showed that the curative effect of LB100 on lipid accumulation was abolished by inhibiting AMPKαin L02 cells.CONCLUSION PP2A inhibition by LB100 significantly ameliorates hepatic
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 Med
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 rat
