沉默信息调节因子 1 与急性肺损伤/急性呼吸窘迫综合征

沉默信息调节因子1(Sirtuin1,silent information regulator 1,SIRT1)是与酿酒酵母沉默信息调节器2(Sir2)同源的去乙酰化酶家族。SIRT1通过介导多条细胞信号通路,在细胞生物学功能和疾病发生机制中发挥关键作用,调节各种疾病的病理进展。在急性肺损伤(acute lung injury,ALI)/急性呼吸窘迫综合征(acute respiratory distress syndrome,ARDS)的动物模型中,SIRT1表达异常,且表达水平与模型的疾病严重程度密切相关,可能成为早期诊治ALI/ARDS新的生物学指标。本文简要综述了SIRT1通过抗炎、抗氧化应激、调节细胞凋亡及自噬、改变血管内皮细胞通透性等途径发挥其减轻ALI/ARDS的作用,探讨SIRT1在ALI/ARDS防治中的潜在价值。     

SIRT1对软骨细胞保护作用的研究进展

沉默信息调节因子2相关酶类1(silent information regulator 2homolog 1,SIRT1)是Sirtuins家族成员之一,属于Ⅲ类组蛋白去乙酰化酶,可对组蛋白和非组蛋白发挥去乙酰化作用。近年来关于SIRT1在骨关节炎中的研究日益增多,尤其是SIRT1对骨关节炎软骨细胞的保护作用倍受关注。本文对SIRT1的生物学特点及其通过抗氧化应激、抗凋亡、抗炎以及调控软骨细胞的分化等途径发挥对软骨细胞的保护作用进行综述,旨在为骨关节疾病的防治提供新的思路。     

SIRT1抑制细菌脂多糖耐受THP-1细胞中IL-1βmRNA的转录

目的 研究细菌脂多糖(LPS)耐受的THP-1细胞中沉默信息调节因子1(SIRTI)对IL-1β转录的调节作用.方法 使用LPS耐受的人单核细胞THP-1模型,染色体免疫沉淀和real-time PCR定量研究1L-1β启动子区SIRT1结合情况和组蛋白H3lys9/H4lys16的乙酰化情况.结果 在LPS耐受的THP-1细胞中,SIRTI对IL-1β启动子区的结合增加约5倍左右(P<0 05).同时伴随着组蛋白H3 lys9/H4 lys16乙酰化的低水平状态(与正常细胞相比P<0.05).SIRT1沉默使IL-1β的转录恢复到正常细胞的68%(P<0 05),同时伴随着组蛋白H3 lys9/H4lys 16乙酰化的增加(P<0.05).然而,正常细胞和耐受细胞p65 lys310乙酰化水平无明显差异.结论 SIRT1抑制LPS耐受的THP-1细胞中IL-113mRNA的转录,其作用与p65 lys310乙酰化无关,但是与IL-1β启动子区乙酰化有关.     

视网膜色素上皮氧化损伤SIRT1表达改变

目的明确氧化应激对视网膜色素上皮细胞(RPE)中去乙酰化酶1(SIRT1)表达的影响。方法以人RPE细胞为实验对象,不同浓度H_2O_2(0、200、300μmol/L)处理RPE细胞,观察处理后24 h细胞形态的改变情况,检测处理后24 h与72 h细胞中SIRT1的mRNA与蛋白表达情况。结果 H_2O_2作用后,随H_2O_2浓度的增加,RPE细胞的形态受损,有凋亡小体的出现;在氧化应激24 h后细胞内SIRT1的转录水平增加,而在氧化应激72 h后SIRT1的蛋白表达显著下降。结论氧化应激可导致RPE细胞形态改变,SIRT1在RPE细胞内维持着氧化与抗氧化应激系统平衡,因此将SIRT1可作为临床上年龄相关性黄斑变性病(AMD)治疗的靶点。     

SIRT1在卵巢衰老方面的研究进展

正卵巢是重要的生殖内分泌器官,随着人类寿命的明显延长和婚育年龄的推迟,如何延长卵巢寿命和保护卵巢功能是人们越来越关注的问题。沉默信息调节因子Sir 2在哺乳类动物中有7个同源基因,其中与酵母菌Sir 2相似度最高的就是SIRT 1。依赖NAD+的组蛋白去乙酰化酶SIRT 1在调节细胞的代谢、分化与衰老等方面都有着关键的影响与作用[1],并且近年也成为越来越多人研究的热点。     

sirt3的作用机制及抗肿瘤研究进展

沉默信息调节因子3(sirt3)是线粒体去乙酰化蛋白,参与线粒体蛋白去乙酰化调节,激活超氧化物歧化酶2(superoxide dismutase 2,SOD2),降低线粒体活性氧(reactive oxygen species,ROS)水平,维持细胞内稳态平衡,调节氧化、激素或者电离辐射等应激反应。sirt3是线粒体高保真蛋白和抑癌基因,其去乙酰化活性与长寿相关,因此,sirt3缺失可导致线粒体代谢异常和细胞损伤,引起与衰老相关的病理症状。本文对sirt3的线粒体定位、调节和抑癌作用进行讨论,阐明sirt3可以维持线粒体完整性和正常代谢活动,某种程度上能够抑制肿瘤的发生。     

去乙酰化酶SIRT3抗衰老研究进展

去乙酰化酶Sirtuin是一个在低等动物中被广泛研究的抗衰老蛋白因子。哺乳动物的同源蛋白家族SIRT3蛋白通过抗氧化机制防御氧自由基氧化应激介导的机体损伤,在抗衰老过程中发挥着重要作用。能量限制可通过增加SIRT3活性来延长寿命,SIRT3作为抗衰老和治疗衰老相关疾病的靶点正在成为研究热点。本文就SIRT3抗衰老的研究进展做一总结。     

SIRT1在氢醌诱导TK6细胞凋亡中的作用

目的构建TK6细胞的沉默信息调节因子1(SIRT1)基因沉默细胞株(TK6-sh SIRT1),初步探讨SIRT1在氢醌诱导TK6细胞凋亡中的作用。方法应用慢病毒介导的RNA干扰技术构建TK6细胞的SIRT1沉默细胞株,并用q PCR和Western blotting联合鉴定干扰效果,比较两种细胞的一般生物学特性(细胞形态、细胞增殖能力和细胞周期分布)。用不同浓度HQ(2.5~40μmol/L)处理TK6和TK6-sh SIRT1细胞48 h后,以CCK-8法检测细胞存活率;以流式细胞术检测细胞周期及凋亡的改变。结果成功筛选出稳定表达的人淋巴母细胞SIRT1缺陷细胞株,与TK6正常细胞株相比,TK6-sh SIRT1细胞中SIRT1在m RNA和蛋白表达水平分别下降了84.6%和94.5%,且生长速度加快了6.57 h,增殖指数增加了11.8%,差异均有统计学意义(P0.05),但细胞形态未出现明显改变。经HQ短时间处理后:两种细胞存活率均呈剂量依赖性降低;相同染毒剂量条件下,TK6-sh SIRT1细胞的存活率均明显低于TK6细胞(P0.05),细胞早期凋亡率高于TK6细胞(P0.05)。结论 SIRT1缺陷可增加TK6细胞对HQ的敏感性。     

miR-494通过抑制SIRT1表达调节人宫颈癌Hela细胞系增殖和迁移

目的观察宫颈癌组织中miR-494的表达情况及其对宫颈癌细胞系Hela增殖和迁移的影响,并对其相关机制进行初步的分析。方法 RT-PCR方法检测miR-494在宫颈癌组织和宫颈癌细胞系中的表达情况。克隆形成实验检测miR-494对宫颈癌细胞系Hela增殖能力的影响;划痕实验检测miR-494对宫颈癌细胞系Hela迁移能力的影响。Target Scans软件预测miR-494可能的靶基因,并采用荧光素酶报告基因实验验证预测的靶基因。Western blot方法检测miR-494对预测靶基因表达的影响。结果 miR-494在宫颈癌组织和宫颈癌细胞系中的表达较正常组织相比显著降低(P0.01)。转染miR-494可显著抑制Hela细胞的增殖和迁移能力(P0.01),而转染anti-miR-494可增加Hela细胞的增殖和迁移能力(P0.01)。Targetsscan软件预测miR-494可能的靶基因为去乙酰化酶1(sirtuin 1,SIRT1),且得到荧光素报告实验结果证实。Western blot结果显示转染miR-494可显著抑制Hela细胞中SIRT1的表达(P0.01),而转染anti-miR-494可增加Hela细胞中SIRT1的表达(P0.01)。结论 miR-494可通过调节SIRT1的表达而发挥宫颈癌抑制作用。     

沉默信息调节因子1小干扰RNA诱导前列腺癌细胞PC3细胞凋亡

摘要:目的　观察沉默信息调节因子1（SIRT1）小干扰RNA（siRNA）对前列腺癌细胞PC3细胞生长增殖、DNA合成、细胞凋亡和Bcl-2和Bax蛋白的表达变化,探讨SIRT1在前列腺癌发生中的可能机制。方法　体外培养PC3细胞,分空白对照组（mock组）,转染阴性对照组（scramble siRNA组）和SIRT1 siRNA转染组;Western blot检测PC3细胞中SIRT1的干涉效能;MTT法测定PC3细胞的增殖率;BrdU掺入法测定DNA合成;流式细胞术检测细胞凋亡;Western blot检测PC3细胞中细胞凋亡关键调控因子Bcl-2和Bax的蛋白表达。结果　与对照组比较,SIRT1 siRNA组SIRT1蛋白表达降低（P＜0.01）,PC3细胞的增殖和DNA合成明显受抑制（P＜0.01）,细胞凋亡比例增加（P＜0.01）,Bcl-2蛋白表达减少,Bax的表达增加。结论　下调SIRT1的表达抑制细胞增殖和DNA合成,诱导前列腺癌PC3细胞发生凋亡,其机制可能与改变细胞凋亡关键调控因子Bcl-2和Bax的蛋白表达相关。     

Antioxidant Supplementation Hinders the Role of Exercise Training as a Natural Activator of SIRT1

Exercise training (ET) is a natural activator of silent mating type information regulation 2 homolog 1 (SIRT1), a stress-sensor able to increase the endogenous antioxidant system. SIRT1 activators include polyphenols and vitamins, the antioxidant properties of which are well-known. Antioxidant supplements are used to improve athletic performance. However, they might blunt ET-related benefits. Middle-distance runners (MDR) taking (MDR-S) or not taking antioxidant supplements (MDR-NoS) were compared with each other and with sedentary subjects (CTR) to evaluate the ET effects on SIRT1 levels and oxidative stress, and to investigate whether an exogenous source of antioxidants could interfere with such effects. Thirty-two MDR and 14 CTR were enrolled. MDR-S took 240 mg vitamin C and 15 mg vitamin E together with mineral salts. SIRT1 mRNA and activity were measured in PBMCs. Total oxidative status (TOS) and total antioxidant capacity (TEAC) were determined in plasma. MDR showed higher levels of SIRT1 mRNA (p = 0.0387) and activity (p = 0.0055) than did CTR. MDR-NoS also showed higher levels than did MDR-S without reaching statistical significance. SIRT1 activity was higher (p = 0.0012) in MDR-NoS (1909 ± 626) than in MDR-S (1276 ± 474). TOS did not differ among the groups, while MDR showed higher TEAC levels than did CTR (2866 ± 581 vs. 2082 ± 560, p = 0.0001) as did MDR-S (2784 ± 643) and MDR-NoS (2919 ± 551) (MDR-S vs. CTR, p = 0.0007 and MDR-NoS vs. CTR, p = 0.003). TEAC (β = 0.4488356, 95% CI 0.2074645 0.6902067; p < 0.0001) and the MDR-NoS group (β = 744.6433, 95% CI 169.9954 1319.291; p= 0.012) predicted SIRT1 activity levels. Antioxidant supplementation seems to hinder the role of ET as a natural activator of SIRT1.     

From clock genes to telomeres in the regulation of the healthspan

Biological clocks are classified into oscillatory (clock genes) and unidirectional hourglass clocks (telomeres). Clock genes align behavioral and biochemical processes with the day/night cycle. Telomeres, the repeated series of DNA sequences that cap the ends of chromosomes, become shorter during cell division. Shortened telomeres have been documented in various pathological states associated with aging. Human activity is driven by NADH and ATP produced from nutrients, and the resulting NAD and AMP play a predominant role in energy regulation. Caloric restriction increases both AMP and NAD and is known to extend the healthspan (healthy lifespan) of animals. Silent information regulator T1 (SIRT1), the NAD-dependent deacetylase, attenuates telomere shortening, while peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α), a master modulator of gene expression, is phosphorylated by AMP kinase and deacetylated by SIRT1. Thus, PGC-1α is a key component of the circadian oscillator that integrates the mammalian clock and energy metabolism. Reactive oxygen species produced in clock mutants result in telomere shortening. The circadian rhythms produced by clock genes and lifestyle factors are ultimately controlled by the human brain and drive homeostatic and hedonic feeding and daily activity.     

Piceatannol and Its Metabolite,Isorhapontigenin, Induce SIRT1 Expression in THP-1 Human Monocytic Cell Line

Piceatannol is a phytochemical that is present in large amounts in passion fruit (Passiflora edulis) seeds, and is an analog of resveratrol. Recently, the absorption and metabolism of piceatannol were investigated in rats, and isorhapontigenin, O-methyl piceatannol, was detected as a piceatannol metabolite in rat plasma. To elucidate the function of piceatannol and its metabolites, we investigated the expression of sirtuin 1 (SIRT1) in THP-1 monocytic cells after treatment with piceatannol and its metabolites, and compared their effects with those of resveratrol and its metabolites. Piceatannol and resveratrol upregulated the expression levels of SIRT1 mRNA and SIRT1 protein. An extract of passion fruit seeds, which contained high levels of piceatannol, also upregulated SIRT1 mRNA expression. As for the metabolites, isorhapontigenin upregulated SIRT1 mRNA expression, whereas resveratrol glucuronides and sulfate did not affect SIRT1 expression. These findings indicate that after intake of piceatannol, not only piceatannol itself, but also its metabolite, isorhapontigenin, contributed to the upregulation of SIRT1 expression.     

Oligonol promotes anti-aging pathways via modulation of SIRT1-AMPK-Autophagy Pathway

BACKGROUND/OBJECTIVESOligonol, mainly found in lychee fruit, is an antioxidant polyphenolic compound which has been shown to have anti-inflammatory and anti-cancer properties. The detailed mechanisms by which oligonol may act as an anti-aging molecule have not been determined.MATERIALS/METHODSIn this study, we evaluated the ability of oligonol to modulate sirtuin (SIRT) expression in human lung epithelial (A549) cells. Oligonol was added to A549 cells and reactive oxygen species production, mitochondrial superoxide formation, and p21 protein levels were measured. Signaling pathways activated upon oligonol treatment were also determined by western blotting. Furthermore, the anti-aging effect of oligonol was evaluated ex vivo in mouse splenocytes and in vivo in Caenorhabditis elegans.RESULTSOligonol specifically induced the expression of SIRT1, whose activity is linked to gene expression, metabolic control, and healthy aging. In response to influenza virus infection of A549 cells, oligonol treatment significantly up-regulated SIRT1 expression and down-regulated viral hemagglutinin expression. Oligonol treatment also resulted in the activation of autophagy pathways and the phosphorylation of AMP-activated protein kinase (AMPK). Furthermore, oligonol-treated spleen lymphocytes from old mice showed increased cell proliferation, and mRNA levels of SIRT1 in the lungs of old mice were significantly lower than those in the lungs of young mice. Additionally, in vivo lethality assay revealed that oligonol extended the lifespan of C. elegans infected with lethal Vibrio cholerae.CONCLUSIONSThese data demonstrated that oligonol may act as an anti-aging molecule by modulating SIRT1/autophagy/AMPK pathways.     

Blood SIRT1 Shows a Coherent Association with Leptin and Adiponectin in Relation to the Degree and Distribution of Adiposity: A Study in Obesity,Normal Weight and Anorexia Nervosa

Sirtuin 1 (SIRT1) is a sensor of cell energy availability, and with leptin and adiponectin, it regulates metabolic homeostasis. Widely studied in tissues, SIRT1 is under evaluation as a plasmatic marker. We aimed at assessing whether circulating SIRT1 behaves consistently with leptin and adiponectin in conditions of deficiency, excess or normal fat content. Eighty subjects were evaluated: 27 with anorexia nervosa (AN), 26 normal-weight and 27 with obesity. Bloodstream SIRT1, leptin and adiponectin (ELISA), total and trunk fat mass (FM) %, abdominal visceral adipose tissue, liver steatosis and epicardial fat thickness (EFT) were assessed. For each fat store, the coefficient of determination (R²) was used to evaluate the prediction capability of SIRT1, leptin and adiponectin. Plasma SIRT1 and adiponectin coherently decreased with the increase of FM, while the opposite occurred with leptin. Mean levels of each analyte were different between groups (p < 0.005). A significant association between plasma variables and FM depots was observed. SIRT1 showed a good predictive strength for FM, particularly in the obesity group, where the best R² was recorded for EFT (R² = 0.7). Blood SIRT1, adiponectin and leptin behave coherently with FM and there is synchrony between them. The association of SIRT1 with FM is substantially superimposable to that of adiponectin and leptin. Given its homeostatic roles, SIRT1 may deserve to be considered as a plasma clinical/biochemical parameter of adiposity and metabolic health.     

Inhibition of mTOR/S6K1/4E-BP1 Signaling by Nutraceutical SIRT1 Modulators

The mTOR pathway plays a crucial role in many human diseases, mostly associated with an over hyperactivity of the mTOR signaling, which makes its inhibitors potentially effective therapeutics. Thus, it is important to consider not only the mTOR pathway, but also all those factors that play a key role in its regulation, such as SIRT1 and AMPK. We previously demonstrated the role of some nutraceutical SIRT1 modulators in AMPK and mTOR pathway, showing the presence of a synergistic effect. Now we take further our research by evaluating the effect of berberine, quercetin, tyrosol, and ferulic acid on the mTOR/S6K1/4E-BP1 signaling, along with the existence of any synergistic effect between the following associations: berberine + tyrosol, tyrosol + ferulic acid, ferulic acid + quercetin. Our results indicate the existence of an important relationship between the substances tested and the pathway of mTOR/S6K1/4E-BP1, a report corroborated by the bond of mTOR with SIRT1/AMPK pathways and by their reciprocal regulation.