Silent information regulator sirtuin 1 ameliorates acute liver failure via the p53/glutathione peroxidase 4/gasdermin D axis

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.

Sirtuin 1 in regulating the p53/glutathione peroxidase 4/gasdermin D axis in acute liver failure

In this editorial,we comment on the article by Zhou et al.The study reveals the connection between ferroptosis and pyroptosis and the effect of silent information regulator sirtuin 1(SIRT1)activation in acute liver failure(ALF).ALF is characterized by a sudden and severe liver injury resulting in significant hepatocyte damage,often posing a high risk of mortality.The predominant form of hepatic cell death in ALF involves apoptosis,ferroptosis,autophagy,pyroptosis,and necroptosis.Glutathione peroxidase 4(GPX4)inhibition sensitizes the cell to ferroptosis and triggers cell death,while Gasdermin D(GSDMD)is a mediator of pyroptosis.The study showed that ferroptosis and pyroptosis in ALF are regulated by blocking the p53/GPX4/GSDMD pathway,bridging the gap between the two processes.The inhibition of p53 elevates the levels of GPX4,reducing the levels of inflammatory and liver injury markers,ferroptotic events,and GSDMDN protein levels.Reduced p53 expression and increased GPX4 on deletion of GSDMD indicated ferroptosis and pyroptosis interaction.SIRT1 is a NAD-dependent deacetylase,and its activation attenuates liver injury and inflammation,accompanied by reduced ferroptosis and pyroptosis-related proteins in ALF.SIRT1 activation also inhibits the p53/GPX4/GSDMD axis by inducing p53 acetylation,attenuating LPS/D-GalN-induced ALF.

Sirtuin 1促进牙周膜干细胞骨向分化的实验研究

目的:研究蛋白酶Sirtuin 1在牙周膜干细胞骨向分化中的作用。方法:筛选人因正畸而拔除的前磨牙,获取牙周膜组织做细胞培养,并行牙周膜干细胞鉴定;实验分为实验组、对照组。实验组1:加入Sirtuin 1激活剂白藜芦醇使其工作浓度为1、5、10mmol/L。实验组2:加入Sirtuin 1抑制剂烟酰胺使其终末工作浓度为1、5、10mmol/L,对照组为空白对照。获取培养细胞后半定量RT-PCR检测Sirtuin 1和各组细胞骨向分化标志物,即碱性磷酸酶,骨桥蛋白,骨钙蛋白和骨涎蛋白。结果:通过检测牙周膜干细胞的蛋白酶Sirtuin 1和骨向分化标志物,即碱性磷酸酶,骨桥蛋白,骨钙蛋白和骨涎蛋白的mRNA含量,显示随着加入白芦藜醇剂量的差异而出现梯度的上调;而随着烟酰胺的浓度的升高而出现梯度的下调。结论:Sirtuin 1可以有效的促进牙周膜干细胞的骨向分化,从而促进牙槽骨再生修复重建,具有良好的临床应用前景。

Hippocampal insulin resistance and the Sirtuin 1 signaling pathway in diabetes-induced cognitive dysfunction

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.

Effects of natural mineral-rich water consumption on the expression of sirtuin 1 and angiogenic factors in the erectile tissue of rats with fructose-induced metabolic syndrome

Consuming a high-fructose diet induces metabolic syndrome （MS）-Iike features, including endothelial dysfunction. Erectile dysfunction is an early manifestation of endothelial dysfunction and systemic vascular disease. Because mineral deficiency intensifies the deleterious effects of fructose consumption and mineral ingestion is protective against MS, we aimed to characterize the effects of 8weeks of natural mineral-rich water consumption on the structural organization and expression of vascular growth factors and receptors on the corpus cavernosum （CC） in 10% fructose-fed Sprague-Dawley rats （FRUCT）. Differences were not observed in the organization of the CC either on the expression of vascular endothelial growth factor （VEGF） or the components of the angiopoietins/Tie2 system. However, opposing expression patterns were observed for VEGF receptors （an increase and a decrease for VEGFR1 and VEGFR2, respectively） in FRUCT animals, with these patterns being strengthened by mineral-rich water ingestion. Mineral-rich water ingestion （FRUCTMIN） increased the proportion of smooth muscle cells compared with FRUCT rats and induced an upregulatory tendency of sirtuin I expression compared with the control and FRUCT groups. Western blot results were consistent with the dual immunofluorescence evaluation. Plasma oxidized low-density lipoprotein and plasma testosterone levels were similar among the experimental groups, although a tendency for an increase in the former was observed in the FRUCTMIN group. The mineral-rich water-treated rats presented changes similar to those observed in rats treated with MS-protective polyphenol-rich beverages or subjected to energy restriction, which led us to hypothesize that the effects of mineral-rich water consumption may be more vast than those directly observed in this study.

Sirtuin 1激活在氯化钴诱导的离体耳蜗缺氧损害中的作用研究

目的观察氯化钴（CoCl2）对耳蜗毛细胞和神经节细胞的损伤模式并探讨Sirtuin 1（SIRT1）在耳蜗缺氧过程中的作用。方法采用CoCl2作用于离体培养的新生大鼠耳蜗组织，通过细胞化学染色和免疫荧光染色确定CoCl2对耳蜗毛细胞存活的影响，采用实时定量PCR方法检测CoCl2作用耳蜗组织后Sirtuin 1mRNA表达的变化。同时使用Sirtuin1激活剂白藜芦醇和Sirtuin 1抑制剂Sirtinol，观察SIRT1在缺氧介导的耳蜗损伤过程中的作用。结果300μmol／L以上浓度CoCl2作用于耳蜗24h可引起内外毛细胞缺失。细胞肿胀明显，神经元胞体变得不规则，数目明显减少，有些神经纤维甚至断裂。CoCl2处理后可引起早期耳蜗组织Sirtuin1基因表达增强，6h达到峰值。白藜芦醇预处理可以显著提高外毛细胞（P〈0．01）和内毛细胞的存活率（P〈0．05）。同时给予Sirtuin1抑制剂Sirtinol，白藜芦醇的保护效应被抵消。结论CoCl2导致耳蜗组织缺氧损害。耳蜗在缺氧过程中Sirtuin1早期上调，可保护耳蜗组织对抗缺氧诱导的细胞损伤。

Sirtuin 1 alleviates endoplasmic reticulum stress-mediated apoptosis of intestinal epithelial cells in ulcerative colitis

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.

Sirtuin 1 in rat orthotopic liver transplantation:An I GL-1 preservation solution approach

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.

Losartan activates sirtuin 1 in rat reduced-size orthotopic liver transplantation

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.

Hydrogen-rich water alleviates constipation by attenuating oxidative stress through the sirtuin1/nuclear factor-erythroid-2-related factor 2/heme oxygenase-1 signaling pathway

BACKGROUND Constipation,a highly prevalent functional gastrointestinal disorder,induces a significant burden on the quality of patients'life and is associated with substantial healthcare expenditures.Therefore,identifying efficient therapeutic modalities for constipation is of paramount importance.Oxidative stress is a pivotal contributor to colonic dysmotility and is the underlying pathology responsible for constipation symptoms.Consequently,we postulate that hydrogen therapy,an emerging and promising intervention,can serve as a safe and efficacious treatment for constipation.AIM To determine whether hydrogen-rich water(HRW)alleviates constipation and its potential mechanism.METHODS Constipation models were established by orally loperamide to Sprague-Dawley rats.Rats freely consumed HRW,and were recorded their 24 h total stool weight,fecal water content,and charcoal propulsion rate.Fecal samples were subjected to 16S rDNA gene sequencing.Serum non-targeted metabolomic analysis,malondialdehyde,and superoxide dismutase levels were determined.Colonic tissues were stained with hematoxylin and eosin,Alcian blue-periodic acid-Schiff,reactive oxygen species(ROS)immunofluorescence,and immunohistochemistry for cell growth factor receptor kit(c-kit),PGP 9.5,sirtuin1(SIRT1),nuclear factor-erythroid-2-related factor 2(Nrf2),and heme oxygenase-1(HO-1).Quantitative real-time PCR and western blot analysis were conducted to determine the expression level of SIRT1,Nrf2 and HO-1.A rescue experiment was conducted by intraperitoneally injecting the SIRT1 inhibitor,EX527,into constipated rats.NCM460 cells were induced with H2O2 and treated with the metabolites to evaluate ROS and SIRT1 expression.RESULTS HRW alleviated constipation symptoms by improving the total amount of stool over 24 h,fecal water content,charcoal propulsion rate,thickness of the intestinal mucus layer,c-kit expression,and the number of intestinal neurons.HRW modulated intestinal microbiota imbalance and abnormalities in serum metabolism.HRW could also reduce intestinal oxidative stress through the SIRT1/Nrf2/HO-1 signaling pathway.This regulatory effect on oxidative stress was confirmed via an intraperitoneal injection of a SIRT1 inhibitor to constipated rats.The serum metabolites,β-leucine(β-Leu)and traumatic acid,were also found to attenuate H2O2-induced oxidative stress in NCM460 cells by up-regulating SIRT1.CONCLUSION HRW attenuates constipation-associated intestinal oxidative stress via SIRT1/Nrf2/HO-1 signaling pathway,modulating gut microbiota and serum metabolites.β-Leu and traumatic acid are potential metabolites that upregulate SIRT1 expression and reduce oxidative stress.

组蛋白去乙酰化酶Sirtuin 1在糖尿病和骨代谢中的研究进展

组蛋白去乙酰化酶Sirtuin 1是第Ⅲ类去乙酰化酶,在糖尿病和骨代谢中起重要作用。Sirtuin 1对糖尿病的影响较明确,是胰岛β细胞的保护性因子,促进胰岛素分泌,增加糖异生,减少氧化应激,改善肝脏、脂肪和骨骼肌的IR。Sirtuin1可促进成骨细胞分化,抑制破骨细胞生成,调节骨重建,还同时影响糖尿病和骨代谢。但是,Sirtuin 1在糖尿病合并骨代谢异常方面的研究正处于开始阶段,多集中在细胞水平的表观遗传学领域。本文就Sirtuin 1在糖尿病和骨代谢中的作用及相关信号转导机制的研究进展进行综述,为糖尿病性骨质疏松症的防治提供新思路。

sirtuin-1在肺泡巨噬细胞金属基质蛋白酶9表达中作用

目的:肺泡巨噬细胞(alveolar macrophages,AM)的金属基质蛋白酶9(matrix metalloproteinases 9,MMP9)表达在慢性阻塞性肺病(chronic obstructive pulmonary disease,COPD)及肺气肿形成中起重要作用,但该细胞对于MMP9表达调控机制尚不明确。本研究就NAD依赖性蛋白脱乙酰酶sirtuin-1(Sirt1)在MMP9表达调控中的可能作用开展研究。方法:体外培养小鼠AM,建立香烟烟雾提取物(cigarette smoking extract,CSE)刺激模型;观察加入Sirt1激动剂白藜芦醇后的细胞内MMP9表达量变化;建立Sirt1基因siRNA干扰模型,观察Sirt1基因被抑制后的AM胞内MMP9表达状况。结果:1%CSE刺激后AM胞内MMP9表达明显增加(P<0.05),此作用可被Sirt1激动剂白藜芦醇所拮抗,其拮抗效应呈浓度依赖性;采用siRNA干扰AM细胞Sirt1基因表达后,AM细胞内MMP9表达明显增加(P<0.05)。结论:Sirt1参与了AM细胞对MMP9的表达调控作用,其可能在COPD的发生发展中起保护性作用。

Increased mitochondrial fission drives the reprogramming of fatty acid metabolism in hepatocellular carcinoma cells through suppression of Sirtuin 1

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.

Sirtuin 1 Mediates Hydrogen Sulfide？induced Cytoprotection Effects in Neonatal Mouse Cardiomyocytes

Background： Current knowledge indicates that oxidative damage and the following inflammation is pivotal pathway for myocardial cell death. In recent decades, hydrogen sulfide （H2S） has been identified as a novel endogenous vasodilator and neuromodulator due to its antioxidation capacity. However, whether H2S pretreatment in neonatal mouse cardiomyocytes is a protection effect against oxidative stress remains elusive. Methods： Primary neonatal mouse cardiomyocytes were isolated and cultured, subsequently, pretreated with the H2S donor, sodium hydrosulfide （NaHS）. Cell viability, lactate dehydrogenase （LDH） release, and reactive oxygen species （ROS） production are evaluated. The levels of superoxide dismutase （Sod2） and Sirtuin 1 （Sirt1）, a deacetylation enzyme, were detected by Western blotting. The statistics was performed using independent＇sample t-test. Results： NaHS （100 μmol/L） had no toxicity to primary neonatal mouse cardiomyocytes. Furthermore, NaHS pretreatment significantly improved neonatal mouse cardiomyocytes survival after H2O2-induced cell death, indicated by the decrease in LDH release （40.00 ± 2.65%vs. 65.33 ± 4.33%, P 〈 0.01） and ROS production （1.90 ±0.33 vs. 4.56 ± 0.56, P 〈 0.05）, and that the salubrious effect was accompanied by the upregulation of Sod2 expression. In addition, the study showed that NaHS pretreatment improved mitochondrial DNA number in neonatal mouse cardiomyocyte. Furthermore, the result demonstrated NaHS increased the expression of Sirt1 in neonatal mouse cardiomyocyte. Ex 527, an inhibitor of Sirt1, could attenuate these effects of NaHS-nduced Sod2 expression and mtDNAnumber increase, furthermore, abrogate the cytoprotective effects of NaHS for neonatal mouse cardiomyocytes. Conclusion： Sirt1 mediated H2S-induced cytoprotection effects in neonatal mouse cardiomyocytes.

Sirtuins与PARP-1在细胞凋亡过程中的相互作用

哺乳动物Sirtuins家族目前共发现7个成员:SIRT1～SIRT7,它们均为NAD+依赖性且从细菌到人类都保守的一类酶.人们已经对这7种去乙酰化酶进行了亚细胞定位.目前,对其研究主要集中在对细胞发育相关的重要转录因子如p53、FOXO家族及相关蛋白的去乙酰化修饰.Sirtuins对许多生理过程有着重要的调节作用,尤其是当发现它们对寿命延长的调控作用后,Sirtuins引起了人们极大的关注,且都发表在世界顶级刊物上.聚ADP核糖聚合酶(poly ADP-ribose polymerase,PARP)是一类存在于大多数真核细胞中的蛋白质翻译后修饰酶,尤其是聚ADP核糖聚合酶1(PARP-1)在细胞内DNA损伤修复等过程中起着重要作用,该酶同样以NAD+作为催化反应的底物.有研究发现,Sirtuins家族成员与PARP-1在细胞内某些重要生理过程中存在着相互作用.本文评述了Sirtuins家族成员、PARP-1的生物学特点,并就其参与哺乳动物细胞凋亡的调控机制和相关信号通路进行了详细的论述,以期对Sirtuins家族成员、PARP-1生物学功能及其相互作用的研究提供理论指导.

Effects of Berberine on Hepatic Sirtuin 1-uncoupling Protein 2 Pathway in Non-alcoholic Fatty Liver Disease Rats Induced by High-fat Diet

Objective To investigate the involvement of sirtuin 1（SIRT1）-uncoupling protein 2（UCP2） pathway in the development of non-alcoholic fatty liver disease and whether berberine exerts its effects by regulating this pathway. Methods Male SD rats were divided into three groups： normal control group, high-fat diet group, and berberine supplement group. The rats in the normal control group were given normal diet while the rats in the other two groups were fed with high-fat diet. Rats in the berberine supplement group were concurrently given berberine（100 mg/kg body weight） once daily. After 16 weeks, the levels of serum, liver lipids, and serum aminotransferase were measured using an automatic biochemical analyzer. Superoxide dismutase（SOD） activity and malondialdehyde（MDA） content in the liver were measured using commercial kits. Histopathological changes of liver tissues were observed by hematoxylin and eosin（HE） staining and Oil Red O staining. The hepatic m RNA and protein levels of SIRT1 and UCP2 were assayed by reverse transcription polymerase chain reaction（RT-PCR） or Western blotting. Results Berberine supplement could significantly decrease the serum and liver lipid contents in rats fed with high-fat diet. Meanwhile, SOD level was significantly elevated, but MDA level was reduced in the liver. The results of HE and Oil Red O staining showed that the hepatic steatosis was alleviated in berberine supplement group. Furthermore, berberine induced an increase in SIRT1 expression but a decrease in UCP2 expression. Conclusion The regulation of hepatic SIRT1-UCP2 pathway may be an important mechanism by which berberine exerts the beneficial effects in NAFLD rats.

Critical roles of sirtuin 1 in vascular aging and abdominal aortic aneurysm

With the support by the National Natural Science Foundation of China and National Science and Technology Support Project,the research team led by Prof.Liu Depei(刘德培)at the State Key Laboratory of Medical Molecular Biology,Institute of Basic Medical Sciences,Chinese Academy of Medical Sciences and Peking Union Medical College,discovered critical roles of sirtuin 1(SIRT1)in the vascular smooth

金合欢素调节Sirt1/AMPK/Nrf2信号通路对糖尿病白内障大鼠氧化应激损伤的影响

目的探讨金合欢素对糖尿病白内障(DC)大鼠氧化应激损伤的影响及其对沉默调节蛋白1(Sirt1)/腺苷酸活化蛋白激酶(AMPK)/核因子E2相关因子2(Nrf2)信号通路的调控作用。方法60只SD大鼠随机分为对照组、模型组、金合欢素低剂量组、金合欢素高剂量组、金合欢素+Sirt1抑制剂(EX527)组,除对照组以外均构建DC大鼠模型,其中,金合欢素低剂量组、金合欢素高剂量组大鼠分别经颈部皮下注射10 mg·kg^(-1)、20 mg·kg^(-1)的金合欢素,金合欢素+EX527组大鼠经颈部皮下注射20 mg·kg^(-1)金合欢素,均为每天2次,同时金合欢素+EX527组大鼠经皮下埋入渗透微型泵每天泵入3.5 mg·kg^(-1)EX527,其余组别均泵入等量生理盐水,给药持续4周。给药结束后,测量血压和空腹血糖(FBG),裂隙灯照射法观察大鼠晶状体混浊状况,HE染色观察晶状体组织病理学变化,ELISA测定血清丙二醛(MDA)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、白细胞介素(IL)-6、IL-1β的含量,Western blot检测Sirt1、p-AMPK、AMPK、Nrf2蛋白表达水平。结果与对照组相比,模型组大鼠晶状体上皮细胞呈片状、条索状,发生迁移性聚集,收缩压、FBG、晶状体混浊评分、MDA、IL-6、IL-1β水平均升高,SOD、GSH-Px含量及Sirt1、p-AMPK/AMPK、Nrf2蛋白表达水平均降低(均为P<0.05);与模型组比较,金合欢素低、高剂量组大鼠晶状体上皮细胞迁移性聚集现象改善,收缩压、FBG、晶状体混浊评分、MDA、IL-6、IL-1β水平均降低,SOD、GSH-Px含量及Sirt1、p-AMPK/AMPK、Nrf2蛋白表达水平均升高(均为P<0.05);与金合欢素高剂量组比较,金合欢素+EX527组晶状体上皮细胞形态改变和聚集现象加重,收缩压、FBG、晶状体混浊评分、MDA、IL-6、IL-1β水平均升高,SOD、GSH-Px含量及Sirt1、p-AMPK/AMPK、Nrf2蛋白表达水平均降低(均为P<0.05)。结论金合欢素可能通过激活Sirt1/AMPK/Nrf2通路保护DC大鼠免受氧化应激损伤。

老年ACS患者血清Sirtuin1、血清淀粉样蛋白A与其冠状动脉病变程度的相关性

目的:探讨老年急性冠状动脉综合征(ACS)患者血清Sirtuin 1、血清淀粉样蛋白A(SAA)与其冠状动脉病变程度的相关性。方法:选择化州市人民医院2018年12月至2020年12月收治的ACS患者共78例作为观察组,选择同期体检受试者62例作为对照组。检测两组受试者血清Sirtuins 1、SAA的水平。依据SYNTAX评分将观察组患者分为低危组(SYNTAX评分为1~22分)30例、中危组(SYNTAX评分为23~32分)22例、高危组(SYNTAX评分≥33分)26例,比较三组患者血清Sirtuins 1、SAA的水平,并采用Pearson相关性分析法分析观察组患者血清Sirtuins 1、SAA水平与SYNTAX评分的相关性。结果:观察组患者血清Sirtuin 1、SAA的水平显著高于对照组受试者(P<0.05)。在观察组中,低危组、中危组、高危组患者血清Sirtuin 1、SAA的水平相比差异显著(P<0.05),中危组患者血清Sirtuin 1、SAA的水平显著高于低危组患者(P<0.05),高危组患者血清Sirtuin 1、SAA的水平显著高于中危组患者(P<0.05)。经pearson相关性分析显示,观察组患者血清Sirtuin 1、SAA的水平与SYNTAX评分呈正相关(P<0.05)。结论:ACS患者血清Sirtuins 1、SAA的水平可显著升高,与其冠状动脉病变的严重程度呈正相关。

Molecular modeling of alkaloids bouchardatine and orirenierine binding to sirtuin-1(SIRT1)

Objective Bouchardatine(1)is a β-indoloquinazoline alkaloid isolated from the plant Bouchardatia neurococca,acting as a modulator of adipogenesis and lipogenesis,and as an anticancer agent.The natural product functions as an activator of proteins adenosine 5’-monophosphate(AMP)-activated protein kinase(AMPK)and sirtuin 1(SIRT1).We used molecular modeling to investigate the SIRT1-binding capacity of compound 1 and various structural analogues,such as orirenierine A(2)and orirenierine B(3)isolated from the medicinal plant Oricia renieri.Methods We investigated the binding to human SIRT1(hSIRT1)of 25 natural products including theβ-indoloquinazoline alkaloids 1−3 and analogues,in comparison with the reference product sirtinol(R and S isomers).A sirtinol binding model was elaborated starting from the closed and open state conformations of the catalytic domain of hSIRT1(PDB structures 4KXQ and 4IG9).For each compound bound to SIRT1,the empirical energy of interaction(ΔE)was calculated and compared to that of sirtinol.Results In our model,compound 1 was found to bind modestly to the sirtinol site of SIRT1.In contrast,the presence of a phenolic OH group at position 7 on the quinazolinone moiety conferred a much higher binding capacity.Compound 2 provided SIRT1 protein complexes as stable as those observed with sirtinol.The replacement of the hydroxy substituent(2)with a methoxy group(3)reduced the SIRT1 binding capacity.Other SIRT1-binding natural products were identified,such as the alkaloids orisuaveolines A and B.Structure-binding relationships were discussed.Conclusion The study underlines the capacity of β-indoloquinazoline alkaloids to interact with SIRT1.This deacetylase enzyme could represent a molecular target for the alkaloid 2.This compound merits further attention for the design of drugs active against SIRT1-dependent pathologies.