几种苯丙素苷的合成及抗肿瘤活性

目的合成单糖苯丙素苷和糖苷衍生物,探讨其抗肿瘤活性.方法以苯乙醇为苷元合成单糖苯丙素苷衍生物,采用MTT法测定抗肿瘤活性.结果共合成了9个新化合物,其结构经NMR 和MS确证.苯丙素苷3,5,8,9和糖苷6,10,n在浓度为10-7～10-5 mol/L时体外抗肿瘤活性较弱.当浓度大于10-5 mol/L时,糖苷10和11则有明显的体外抗肿瘤活性.结论单糖苯丙素苷抗肿瘤活性较弱;糖苷抗肿瘤活性与苷元的结构有关.     

Synthetic di-sulfated iduronic acid attenuates asthmatic response by blocking T-cell recruitment to inflammatory sites

Identification of carbohydrate sequences that determine affinity to specific chemokines is a critical step for strategies to interfere with chemokine-mediated leukocyte trafficking. Here, we first characterized the development of allergic asthma in Tie2-dependent and inducible Ext1-knockout (Tie2-Ext1^iKO) mice. We showed that heparan sulfate is essential for leukocyte recruitment in the peribronchial region and bronchoalveolar lavage fluid (BALF), and is crucial for induction of airway hyperresponsiveness. Our glycan microarray showed a unique affinity profile of chemokine CCL20 to substructures of heparin and heparin-like oligo/di/monosaccharides. Among them, we identified a synthetic and not naturally occurring monosaccharide, 2,4-O-di-sulfated iduronic acid (Di-S-IdoA), as a potential inhibitor for CCL20–heparan sulfate interaction. Mice injected with Di-S-IdoA via tail vain or nasal inhalation showed attenuated leukocyte recruitment into inflammatory sites and BALF. These results demonstrate a critical role of chemokine–heparan sulfate interaction in the asthma development and Di-S-IdoA as a potential drug for asthma treatment.Asthma is a common allergic disease characterized by chronic airway inflammation, mucus hypersecretion, and airway hyperreactivity to inhaled allergens (1). Despite the importance of T lymphocytes in adaptive immunity and host defense, their accumulation in airway in allergic asthma causes Th2-mediated pulmonary inflammation. The asthmatic inflammatory response is orchestrated by T-cell trafficking network among lung, blood circulation, secondary lymphoid organ, and peripheral tissue (2). Of note, the significant increase of T cells in the airway in asthma is mostly due to T-cell recruitment from regional lymph nodes rather than their proliferation at the inflamed site (3). Therefore, a therapeutic approach that shuts off the trafficking pathway of pathogenic T cells should significantly inhibit the Th2-mediated inflammation in allergic asthma.It is well known that the destination of T-cell trafficking pathway is tightly restricted by the profile of chemokines, lipid chemoattractants, and T-cell chemokine receptors. As a part of immune surveillance, naïve T cells and central memory T cells constantly access secondary lymphoid organs from blood circulation via specialized high endothelial venules (HEVs). The interaction between T cells and HEV cells includes in a stepwise manner (4, 5), L-selectin–dependent tethering and rolling, activation, firm arrest, and transendothelial migration. Besides 6-sulfo sialyl Lewis X as a L-selectin ligand, HEVs constitutively express chemokine CCL21 and CCL19 and attract T cells that express its cognate receptor CCR7 (5). In contrast to this homeostatic homing, circulating T cells interact with inflamed blood vessels in lung after asthmatic exposure to an inhaled allergen. Among numerous combinations of chemokines and their receptors, there is considerable evidence that CCL20 and its cognate receptor CCR6 may contribute to the pathogenesis of asthma (6). CCL20-CCR6 plays a key role in the recruitment of Th17 (7) cells and Th2 cells (8). Indeed, CCL20 is highly enriched on inflammatory epithelium (9) and CCR6 is expressed on memory T cells infiltrated in the lung during allergic inflammation (7). In addition, CCR6-deficient mice have decreased airway responsiveness, and reduced recruitment of eosinophils into lung (10, 11). These findings suggest that CCL20-CCR6 axis is a putative target for the treatment of asthma.Cumulative evidence in vivo and in vitro indicates that chemokines cannot be functionally active in HEVs and inflamed sites without their interaction with heparan sulfate (12). Heparan sulfate protects chemokines from proteolysis, immobilizes them on the endothelium surface and produces chemokine gradients in the vasculature. Heparan sulfate is composed of repeating disaccharide units of uronic acid [glucuronic acid (GlcA) or iduronic acid (IdoA)] and N-acetylglucosamine (GlcNAc) carbohydrates. Some of GlcA (or IdoA) carbohydrates are subsequently O-sulfated, and GlcNAc carbohydrates are partially modified with N-deacetylation and N-sulfation (13). Previous reports have indicated that the sulfation patterns in heparan sulfate are more restricted than expected (14), and the sulfation is associated with respiratory distress (15) and asthma (16). It is believed that there are specific interactions between heparan sulfate and chemokines (17). Nevertheless, the nontemplate nature of long carbohydrate chains (<25,000 disaccharide units) and conformational plasticity still make it difficult to identify the common sequences of heparan sulfate that display affinity to specific chemokines. In this regard, our previously established glycan microarray system (18, 19) is a powerful tool to define the selectivity in heparan sulfate–chemokine interactions.Recently, we established the exostoses-1 (Ext1) gene conditional knockout Tie2-Ext1^iKO mouse model, in which GlcA/IdoA-GlcNAc repeat of heparan sulfate can be abrogated in endothelial cells in a tetracycline-inducible manner (20). In this study, Tie2-Ext1^iKO mouse showed significant reduction of both leukocyte recruitment to lung tissues and of airway hyperresponsiveness in ovalbumin (OVA) asthma model. Moreover, glycan microarray analysis surprisingly identified that an unnatural and synthetic monosaccharide, 2,4-O-di-sulfated iduronic acid (Di-S-IdoA) has a high affinity to recombinant CCL20. Intravenous and inhalation challenges of Di-S-IdoA significantly inhibited the leukocyte infiltration in bronchoalveolar lavage fluid (BALF). Our finding that even a monosaccharide can attenuate airway inflammation suggests its potential use as an antiasthma therapy that can be administered by inhalation.     

p38 MAPK及其抑制剂在胰岛素调节GLUT4活性中的作用

目的:探讨p38丝裂原活化蛋白激酶(p38 MAPK)及其抑制剂SB203580在胰岛素调节葡萄糖转运子4(GLUT4)活性机制中的作用。方法:分别测定胰岛素和SB203580孵育条件下骨骼肌细胞p38 MAPK的磷酸化水平和活性;检测p38 MAPK或SB203580是否与GLUT4直接结合;并测定SB203580对光化学标记细胞膜上的GLUT4的影响。结果:与胰岛素孵育0min时相比,100nmol/L胰岛素使p38 MAPK磷酸化水平增加,最大值为0min时的(2.43±0.21)倍;胰岛素还使p38α和p38βMAPK的活性分别增加了(10.13±0.48)和(7.92±2.17)倍;SB203580可抑制胰岛素的作用;p38 MAPK在体内不与GLUT4直接结合;SB203580仅抑制胰岛素刺激下的GLUT4光化学标记。结论:p38MAPK或SB203580不直接与GLUT4结合;对SB203580敏感的分子参与了胰岛素调节GLUT4活性的作用。     

虫草多糖中单糖组成的柱前衍生化HPLC分析

建立了柱前衍生化HPLC法测定虫草多糖中单糖的组成及摩尔比。采用C18柱,以0.1mol/L磷酸盐缓冲液(pH6.7)-乙腈(83∶17)为流动相,检测波长254nm。衍生化试剂为1-苯基-3-甲基-5-吡唑啉酮。所测3批样品中虫草多糖由甘露糖、葡萄糖、半乳糖3种单糖组成,单糖的摩尔比约为2∶2∶1。平均回收率分别为101.0%、98.6%和99.2%,RSD分别为1.9%、1.6%和1.2%。     

高效液相法测定黄芪中性多糖的单糖组成

目的:采用高效液相法测定黄芪中性多糖的单糖组成。方法:正交设计优选三氟乙酸水解黄芪中性多糖的条件;水解产物直接采用高效液相-视差检测器(HPLC-RID)检测或经1-苯基-3-甲基-5-吡唑啉酮柱前衍生化后高效液相-二极管阵列检测器(HPLC-DAD)检测两种方法,以6种单糖为对照,测定水解产物中单糖的组成。结果:黄芪中性多糖的三氟乙酸完全酸水解最佳条件为采用1M TFA,水解温度100℃,水解时间5 h;两种高效液相色谱法测得水解产物中的单糖均为葡萄糖。结论:采用三氟乙酸完全酸水解条件和高效液相色谱法测定单糖的方法简便易行,可用于黄芪中性多糖的单糖组成研究。     

芦笋多糖提取、单糖组分分析及定量测定

目的提取芦笋多糖,纯化后分析其单糖组分并测定总糖,为今后芦笋多糖研究提供参考。方法水提醇沉法提取粗多糖,Sevage法除蛋白,H2O2脱色,高效毛细管电泳(HPCE)测定单糖组成,苯酚-硫酸法测定多糖。结果芦笋粗多糖主要单糖组成为木糖、果糖、鼠李糖、阿拉伯糖、半乳糖,其质量分数分别为3.44%、7.92%、10.52%、17.15%、41.85%。以单糖混合物为对照品测得粗多糖中总糖的质量分数为79.14%。结论高效毛细管电泳分离度高,可用于单糖组分分析;苯酚-硫酸法实验操作简便,准确可靠,可用于芦笋多糖的测定。     

Monosaccharide Transport Across Membranes of Human Spermatozoa

A method for determination of the monosaccharide uptake into human spermatozoa is described. Intracellular monosaccharide concentrations were calculated on the basis of determination of intracellular radioactivity after incubation of the cells with labelled monosaccharide and using a mathematical procedure to approximate the intracellular space of spermatozoa. The D-fructose uptake depends on the extracellular D-fructose concentration in a hyperbolic manner. Half maximal saturation is present at 4,1 mM. This corresponds closely with the lowest limit of D-fructose concentration in human fertile semen.     

P-ERK、P-p38及iNOS、GLUT4在冠心病患者冬眠心肌中表达及意义

目的探讨冬眠心肌（HM）细胞内磷酸化ERK（P-ERK）、磷酸化p38（P-p38）、葡萄糖转运因子4（GLUT4）、诱导型一氧化氮合酶（iNOS）的变化和意义，探讨P-ERK、P-p38与GLUT4、iNOS的关系。方法选择行冠脉搭桥手术的冠心病患者10例，术前1周用多巴酚丁胺超声负荷试验结合多普勒组织成像确定HM及正常心肌（NM）的存在部位，术中根据检测结果取材，用免疫印迹法检测P-ERK、P-p38、iNOS、GLUT4的表达情况，分析HM与NM的P-ERK、P-p38、iNOS、GLUT4含量；分析四者之间的相关性。结果HM细胞内P-ERK、P-p38、GLUT4、iNOS水平较正常心肌高；P-ERK与GLUT4呈正相关（r=0.665，P〈0.05），P-p38与GLUT4、iNOS呈正相关（r=0.708、0.676，P〈0.05）。结论心肌缺血缺氧可触发ERK、p38活化，活化的ERK、p38促使心肌细胞增加GLUT4及iNOS表达，促进HM形成。     

柱前衍生-高效毛细管电泳法测定刺糖多糖中单糖的组成

目的:分析测定刺糖多糖中单糖的组成。方法:将刺糖多糖水解成单糖,1-苯基-3-甲基-5-吡唑啉酮(PMP)衍生化,采用高效毛细管电泳法在245 nm紫外检测分离测定各单糖。结果:刺糖多糖中阿拉伯糖、葡萄糖、鼠李糖、半乳糖、甘露糖、葡萄糖醛酸、半乳糖醛酸的摩尔比为2.80∶38.61∶5.28∶3.76∶1.91∶3.82∶2.45,且刺糖多糖中葡萄糖的含量为35.65%。结论:本法测定刺糖多糖的单糖组分操作简便,灵敏度高,结果准确可靠,可用于刺糖多糖单糖组成测定和质量控制。     

气相色谱法分析方格星虫多糖的单糖组成

目的:研究方格星虫多糖的单糖组成。方法:采用3 mol.L-1三氟乙酸将方格星虫多糖水解成单糖,然后与盐酸羟胺进行衍生化反应,采用气相色谱法对其单糖组成进行分析。结果:方格星虫多糖的单糖组成主要为阿拉伯糖和葡萄糖,其质量分数分别为7.91%和79.32%。结论:此法简单、快速,重现性好,可用于方格星虫多糖的单糖组成分析。