羟基酪醇抗肿瘤机制研究进展

羟基酪醇是一种存在于橄榄中的多酚类化合物,具有良好的生物学效应.大量文献表明,羟基酪醇可以诱导多种肿瘤增殖抑制以及凋亡发生.作为一种含酚羟基化合物,羟基酪醇容易发生自氧化,加速其在体外的降解,同时生成过氧化氢.本文综述了羟基酪醇在肿瘤防治领域的研究进展及相应的机制研究,重点就羟基酪醇的自氧化在肿瘤治疗预防中所起的作用进行探讨.     

羟基酪醇抑菌活性及抑菌稳定性研究

本研究探究了羟基酪醇对大肠杆菌、金黄色葡萄球菌、铜绿假单胞杆菌和枯草芽孢杆菌等四种供试菌的抑菌活性及抑菌稳定性。采用试管半倍稀释法确定MIC和MBC,并探讨羟基酪醇对供试菌的生长和细胞膜完整性的影响以及在不同介质下的抑菌稳定性。结果表明,羟基酪醇对大肠杆菌、金黄色葡萄球菌、铜绿假单胞杆菌和枯草芽孢杆菌的MIC分别为0.625、0.625、1.250、2.500 mg/mL,MBC分别为1.250、1.250、2.500、5.000 mg/mL。与对照组相比,四种供试菌核酸和可溶性蛋白泄漏显著,细胞膜的完整性被破坏。在不同NaCl浓度下,羟基酪醇对枯草芽孢杆菌的抑菌活性稳定;在1.0%和2.0%NaCl浓度下,羟基酪醇对大肠杆菌和铜绿假单胞杆菌的抑菌活性稳定;在2.0%NaCl介质下低浓度的羟基酪醇对金黄色葡萄球菌的抑菌活性稳定,在0.5%、1.5%和2.0%NaCl介质下高浓度的羟基酪醇对金黄色葡萄球菌的抑菌活性稳定。在蔗糖介质中,羟基酪醇对四种供试菌的抑菌活性均不稳定。因此,羟基酪醇可以作为一种新型的防腐剂。     

线粒体LncRNA

长链非编码RNA（long noncoding RNAs,lncRNAs）是一类长度大于200个核苷酸的非蛋白质编码RNA。绝大多数lncRNA来源于核基因组。但近年研究发现,一些lncRNA是由线粒体基因组编码、转录而成,或定位于线粒体。本文将从线粒体lncRNA的发现与主要种类、线粒体lncRNA的加工和结构,以及它们的功能和应用等几个方面,对线粒体lncRNA进行阐述。线粒体lncRNA可能成为心血管疾病或肿瘤诊断的生物标志物,或在调控线粒体基因表达等方面发挥重要功能。     

代谢工程改造大肠杆菌合成羟基酪醇

羟基酪醇是重要精细化学品,作为天然抗氧化剂被广泛应用于食品、医药领域。利用合成生物学技术生产羟基酪醇具有重要意义。本文克隆并功能鉴定了来源于大肠杆菌Escherichia coli BL21的羟化酶编码基因HpaBC,结果表明该酶的两个亚基均能成功表达并能催化酪醇生成羟基酪醇。通过CRISPR-Cas9技术将由tac启动子调控的HpaBC基因表达盒整合到前期构建的酪醇高产菌株YMG5A*R基因组中,同时删除副产物乙酸的合成途径,获得大肠杆菌代谢工程菌株YMGRD1H1。摇瓶发酵实验结果表明,重组菌株能够直接利用葡萄糖生产羟基酪醇,产量达到1.81 g/L,同时发现几乎没有副产物积累。5 L发酵罐规模的流加补料发酵实验表明,羟基酪醇最高产量达到2.95 g/L,是目前文献报道以葡萄糖从头合成羟基酪醇的最高水平。通过系统改造大肠杆菌,实现了羟基酪醇的大量合成,为进一步构建具有工业应用潜力的羟基酪醇细胞工厂奠定了基础,也为拓展芳香族化合物的微生物制造路线提供了有益的参考。     

4-羟基苯乙酸-3-羟化酶A重组表达菌株的构建及其对羟基酪醇的生物转化研究

目的:构建表达4-羟基苯乙酸-3-羟化酶A(4-hydroxyphenylacetate-3-hydroxylase A,HHA)的重组菌株,进而以酪醇为底物,利用重组菌株转化生产羟基酪醇。方法:选择大肠杆菌BL21(DE3)为模板来扩增HHA基因,经酶切后连接到表达载体p ET-28a中,获得重组表达载体p ET28a-HHA,将重组载体转化到感受态细胞BL21(DE3),在重组菌液中加入适量酪醇,利用胞内的重组酶对酪醇加羟基合成羟基酪醇,细胞离心后,分别采用薄层层析法和气质联用法检测上清液中羟基酪醇的转化结果。结果:IPTG诱导表达后,经SDS-PAGE分析获得分子质量分别为58.8k Da和18.5k Da的两条蛋白质条带。薄层层析法和气质联用法均检测到催化产物羟基酪醇的生成。结论:成功构建了表达HHA的重组菌株,该菌株可有效将酪醇转化为羟基酪醇。     

线粒体移植治疗心血管疾病研究进展

心血管疾病的发病率和死亡率逐年升高,且在世界范围内的疾病负担中占据首位。线粒体功能异常可引起细胞到组织的病变,多种心血管疾病被证实与线粒体功能障碍有关。线粒体移植(mitochondria transplantation, MTP)是一种新兴的治疗手段,用于治疗因线粒体功能障碍引起的组织损伤。经过十多年从基础实验到临床试验的发展,MTP在心血管疾病中的治疗作用逐渐被证实,并且备受关注。该文就MTP的研究基础及其在心血管疾病中的研究进展进行综述。     

mtDNA拷贝数的生物学意义及其调控

线粒体是细胞能量和自由基代谢中心,并在细胞凋亡、钙调控、细胞周期和信号转导中发挥重要作用,维持线粒体功能正常对于细胞正常行使职能意义重大。线粒体的功能与线粒体DNA（mitochondrial DNA,mtDNA）的数量和质量紧密相关,mtDNA的数量即mtDNA拷贝数又受到mtDNA质量的影响,因此mtDNA拷贝数可作为线粒体功能的重要表征。mtDNA拷贝数变异引起线粒体功能紊乱,进而导致疾病发生。本文综述了mtDNA拷贝数变异与神经退行性疾病、心血管疾病、肿瘤等疾病的发生发展和个体衰老之间的关系,以及mtDNA复制转录相关因子、氧化应激、细胞自噬等因素介导mtDNA拷贝数变异的调控机制。以期为进一步深入探究mtDNA拷贝数调控的分子机制,以及未来治疗神经退行性疾病、肿瘤及延缓衰老等提供一定的理论基础。     

细胞间线粒体转运的研究进展

线粒体是真核生物能量代谢的重要细胞器,是细胞进行氧化磷酸化生成ATP的主要场所.他参与完成细胞能量代谢、维持离子浓度梯度、传递细胞凋亡信号等生理功能.阿尔茨海默病、帕金森病、心肌梗塞等疾病与线粒体功能异常相关.近年来发现,由创伤或炎症造成脑、心脏、肺缺氧时在细胞间会发生线粒体转移.线粒体转移,作为一种进化上保守的现象可能与神经降解、心血管疾病等相关.     

营养所与瑞士DSM营养产品公司合作研究取得进展

视网膜黄斑病是导致老年人失明的主要原因。全世界大约有三千万人罹患此病。目前对该病的机制并不清楚。流行病学研究发现吸烟可能是该病的主要危险因子之一。中科院上海生科院营养科学研究所博士研究生刘中博等在刘健康教授的指导下，与瑞士DSM营养产品公司（DSM Nutrition Products）的科学家合作，对橄榄油提取物——羟基酪醇对视网膜色素上皮细胞的作用进行了研究。     

心磷脂重构与心血管疾病

心磷脂（cardiolipin, CL）是线粒体内膜的特征性磷脂,参与线粒体嵴的形成。心磷脂在线粒体内的合成伴随着特殊的分子重构过程,从而使其自身的4条酰基链形成特定的组成,以发挥其特殊的生理功能。研究发现,心磷脂重构对维持线粒体的形态及功能至关重要,其重构异常是大多数心血管疾病（cardiovascular disease, CVD）共有的病理现象,相应的分子机制研究得到了广泛关注。本文主要对心磷脂的理化特性及其生物合成途径,以及心磷脂重构在巴氏综合征（Barth syndrome, BTHS）、糖尿病心肌病（diabetic cardiomyopathy, DCM）以及心力衰竭（heart failure, HF）等心血管疾病的病理生理过程研究中的进展进行综述,以期为与心磷脂重构相关的心血管疾病的病理生理基础研究和药物干预的分子机制研究提供参考。     

Anti-proliferative and apoptotic effects of oleuropein and hydroxytyrosol on human breast cancer MCF-7 cells

Olive oil intake has been shown to induce significant levels of apoptosis in various cancer cells. These anti-cancer properties are thought to be mediated by phenolic compounds present in olive. These beneficial health effects of olive have been attributed, at least in part, to the presence of oleuropein and hydroxytyrosol. In this study, oleuropein and hydroxytyrosol, major phenolic compound of olive oil, was studied for its effects on growth in MCF-7 human breast cancer cells using assays for proliferation (MTT assay), cell viability (Guava ViaCount assay), cell apoptosis, cellcycle (flow cytometry). Oleuropein or hydroxytyrosol decreased cell viability, inhibited cell proliferation, and induced cell apoptosis in MCF-7 cells. Result of MTT assay showed that 200 μg/mL of oleuropein or 50 μg/mL of hydroxytyrosol remarkably reduced cell viability of MCF-7 cells. Oleuropein or hydroxytyrosol decrease of the number of MCF-7 cells by inhibiting the rate of cell proliferation and inducing cell apoptosis. Also hydroxytyrosol and oleuropein exhibited statistically significant block of G₁ to S phase transition manifested by the increase of cell number in G₀/G₁ phase.     

Inhibition of peroxynitrite dependent DNA base modification and tyrosine nitration by the extra virgin olive oil-derived antioxidant hydroxytyrosol

Hydroxytyrosol is one of the o-diphenolic compounds in extra virgin olive oil and has been suggested to be a potent antioxidant. The superoxide radical (O2*-) and nitric oxide (NO*) can react very rapidly to form peroxynitrite (ONOO ), a reactive tissue damaging species thought to be involved in the pathology of several chronic diseases. Hydroxytyrosol was highly protective against the peroxynitrite-dependent nitration of tyrosine and DNA damage by peroxynitrite in vitro. Given that extra virgin olive oil is consumed daily by many humans, hydroxytyrosol derived from this diet could conceivably provide a defense against damage by oxidants in vivo. The biological activity of hydroxytyrosol in vivo will depend on its intake, uptake and access to cellular compartments.     

The enantioselective immunoaffinity extraction of an optically active ibuprofen-modified peptide fragment

Recent in vitro studies have demonstrated antioxidant properties of some virgin olive oil phenolic compounds. One of the prerequisites to extrapolate these data to an in vivo situation is the knowledge of their bioavailability in humans. In the present work we describe an analytical method which enables us to perform hydroxytyrosol and tyrosol quantitative determinations in human urine. This method was successfully used in bioavailability studies of both phenolic compounds after acute olive oil administration. Virgin olive oil was administered to healthy volunteers after a low phenolic diet. The dose administered of both phenolic compounds was estimated in reference to free forms of hydroxytyrosol and tyrosol present in virgin olive oil extracts before and after being submitted to hydrolytic conditions. These conditions mimic those occurring during digestion. Urine samples were collected before and after acute olive oil intake and analyzed by capillary gas chromatography-mass spectrometry. Hydroxytyrosol and tyrosol urinary recovery increased in response to olive oil administration, obtaining maximal values in the first 4 h. Our results further indicate that hydroxytyrosol and tyrosol are mainly excreted in conjugated form, since only 5.9 +/- 1.4% (hydroxytyrosol) and 13.8 +/- 5.4% (tyrosol) of the total amounts excreted in urine were in free form.     

Major phenolic compounds in olive oil: metabolism and health effects

It has been postulated that the components in olive oil in the Mediterranean diet, a diet which is largely vegetarian in nature, can contribute to the lower incidence of coronary heart disease and prostate and colon cancers. The Mediterranean diet includes the consumption of large amounts of olive oil. Olive oil is a source of at least 30 phenolic compounds. The major phenolic compounds in olive oil are oleuropein, hydroxytyrosol and tyrosol. Recently there has been a surge in the number of publications that has investigated their biological properties. The phenolic compounds present in olive oil are strong antioxidants and radical scavengers. Olive "waste water" also possesses compounds which are strong antioxidant and radical scavengers. Typically, hydroxytyrosol is a superior antioxidant and radical scavenger to oleuropein and tyrosol. Hydroxytyrosol and oleuropein have antimicrobial activity against ATTC bacterial strains and clinical bacterial strains. Recent syntheses of labeled and unlabelled hydroxytyrosol coupled with superior analytical techniques have enabled its absorption and metabolism to be studied. It has recently been found that hydroxytyosol is renally excreted unchanged and as the following metabolites as its glucuronide conjugate, sulfate conjugate, homovanillic acid, homovanillic alcohol, 3,4-dihydroxyphenylacetic acid and 3,4-dihydroxyphenylacetaldehyde. Studies with tyrosol have shown that it is excreted unchanged and as its conjugates. This review summarizes the antioxidant abilities; the scavenging abilities and the biological fates of hydroxytyrosol, oleuropein and tyrosol which have been published in recent years.     

Postprandial LDL phenolic content and LDL oxidation are modulated by olive oil phenolic compounds in humans

Olive oil phenolic compounds are potent antioxidants in vitro, but evidence for antioxidant action in vivo is controversial. We examined the role of the phenolic compounds from olive oil on postprandial oxidative stress and LDL antioxidant content. Oral fat loads of 40 mL of similar olive oils, but with high (366 mg/kg), moderate (164 mg/kg), and low (2.7 mg/kg) phenolic content, were administered to 12 healthy male volunteers in a cross-over study design after a washout period in which a strict antioxidant diet was followed. Tyrosol and hydroxytyrosol, phenolic compounds of olive oil, were dose-dependently absorbed (p<0.001). Total phenolic compounds in LDL increased at postprandial state in a direct relationship with the phenolic compounds content of the olive oil ingested (p<0.05). Plasma concentrations of tyrosol, hydroxytyrosol, and 3-O-methyl-hydroxytyrosol directly correlated with changes in the total phenolic compounds content of the LDL after the high phenolic compounds content olive oil ingestion. A 40 mL dose of olive oil promoted a postprandial oxidative stress, the degree of LDL oxidation being lower as the phenolic content of the olive oil administered increases. In conclusion, olive oil phenolic content seems to modulate the LDL phenolic content and the postprandial oxidative stress promoted by 40 mL olive oil ingestion in humans.     

Chemical composition and nutritional function of olive (<Emphasis Type="Italic">Olea europaea</Emphasis> L.): a review

The olive (Olea europaea L.) is a widely-distributed plant that originated in the Mediterranean region. Its fruit is commonly used to produce olive oil, table olives, and other by-products. The main nutrient of the olive fruit is fat, predominantly monounsaturated fatty acids (MUFA). Olives are also rich in carbohydrates, vitamins, and minerals. Increasing numbers of investigations show that the health benefits of the ‘Mediterranean diet’ are associated with lower incidences of chronic degenerative diseases and higher life expectancy. These benefits have been attributed to the dietary consumption of olive oil. Furthermore, epidemiological data suggest that phenolic components and other antioxidants in olive oil are responsible for some of these benefits. Remarkably, these minor components play significant roles in reducing the incidences of atherosclerosis, cardiovascular disease, neurodegenerative diseases, and certain types of cancer. We reviewed the main olive products and the nutritional composition of olive oil focusing on fatty acids, phenolic compounds, and other antioxidants. We also discuss the chief chemical constituents relevant to the biological activity of olive oil, the metabolism and bioavailability of olive oil phenolic compounds, and the antioxidant activity of metabolites. Finally, we outline recent advances, potential applications, and limitations of developments in the olive oil industry, aiming to provide a theoretical basis for further research and to broaden the prospect of its application to healthy diets.     

Olive oil hydroxytyrosol protects human erythrocytes against oxidative damages

Hydroxytyrosol, the major representative phenolic compound of virgin olive oil, is a dietary component. Its possible protective effect on hydrogen peroxide (H(2)O(2))-induced oxidative alterations was investigated in human erythrocytes. Cells were pretreated with micromolar hydroxytyrosol concentrations and then exposed to H(2)O(2) over different time intervals. Subsequently, erythrocytes were analyzed for oxidative hemolysis and lipid peroxidation. Our data demonstrate that hydroxytyrosol prevents both oxidative alterations, therefore, providing protection against peroxide-induced cytotoxicity in erythrocytes. The effect of oxidative stress on erythrocyte membrane transport systems, as well as the protective role of hydroxytyrosol, also were investigated in conditions of nonhemolytic mild H(2)O(2) treatment. Under these experimental conditions, a marked decrease in the energy-dependent methionine and leucine transport is observable; this alteration is quantitatively prevented by hydroxytyrosol pretreatment. On the other hand, the energy-independent glucose transport is not affected by the oxidative treatment. The reported data give new experimental support to the hypothesis of a protective role played by nonvitamin antioxidant components of virgin olive oil on oxidative stress in human systems.     

Hydroxytyrosol, as a component of olive mill waste water, is dose- dependently absorbed and increases the antioxidant capacity of rat plasma

Hydroxytyrosol is the most potent phenolic antioxidant of olive oil and olive mill waste water (OMWW) and its biological activities have stimulated research on its potential role in cardiovascular protection. However, evidence of the absorption of OMWW phenolics and on their possible in vivo activity has, until now, never been provided. Three groups male Sprague-Dawley rats were administered 1, 5, or 10 mg/Kg of the OMWW extract, respectively, providing 41.4, 207, and 414 μg/Kg of hydroxytyrosol, respectively. Urine was collected for 24 h and the urinary levels of hydroxytyrosol were quantified by mass spectrometry. Hydroxytyrosol was dose-dependently (R²=0.95) absorbed and excreted in the urines mostly as a glucuronide conjugate. Further, the administration of an hydroxytyrosol-rich OMWW extract (10 mg/kg) to the rats was also associated with an increase of their plasma antioxidant capacity. Future experiments will eventually further clarify its metabolic fate and its in vivo actions.