大连化物所开发超灵敏DPP–IV活性检测技术提供个性化用药新工具

<正>不久前,中国科学院大连化学物理研究所药用资源开发研究组葛广波、杨凌团队研发了一种全新的二肽基肽酶–IV(DPP–IV,CD26)高特异性荧光探针,并将其用于人血及组织中DPP–IV的活性检测以及活细胞和组织层面的目标酶功能成像研究,相关研究成果发表在Biosensors and Bioelectronics上。DPP–IV是哺乳动物体内分布的一种重要的丝氨酸水解酶,其参与体内多种生物活性多肽(如肠促胰岛素、神经肽、胃泌素释放肽、生长激素释放激素等)的水解进而导     

具有合成核酸活性的多肽 Ⅰ.C-端去四肽和去六肽核糖核酸酶A及其水解和合成活性

核糖核酸酶A(RNase A)的结构与功能的关系虽属已知,但大都限于水解作用方面,而关于合成作用方面的报道则颇少.根据前人用抑制剂法所得羧甲基化核糖核酸酶A的衍生物(CM-RNase A),和用合成法所得分子较简单的RNase A的类似物的研究结果,似乎RNaseA分子中的His_(119)与Lys_(41)残基与酶的合成活性无关.这些衍生物和类似物的合成活性都比它们的水解活性高,但不论它们的合成或水解活性都很显著地低于天然酶的活     

TEMPO/NaBr/NaClO体系催化氧化法合成α-D-葡萄糖醛酸

以α-D-葡萄糖为起始物,用TEMPO/NaBr/NaClO体系催化氧化法合成α-D-葡萄糖醛酸。合成过程为:首先对α-D-葡萄糖上的C1位进行甲基化保护,然后用TEMPO/NaBr/NaClO体系对伯醇羟基进行催化氧化转化为羧基,最后脱甲基。对第三步稀盐酸水解法脱甲基的条件作了优化,分别水解15h、30h、45h、58h、65h,高效液相色谱(HPLC)结果显示,在水解58h时甲基葡萄糖醛酸钠基本水解完毕,葡萄糖醛酸水解得率最高,水解得率为64.9%。经过高效液相色谱提纯后的葡萄糖醛酸熔点为164.3～165.2℃(m.p.165℃),得率(基于α-D-葡萄糖)为45.2%。     

糖类物质的衍生化试剂——氘代PMP和类似物的合成及其衍生化性能

在冰醋酸催化的无溶剂条件下,于室温合成了氘代PMP及其类似物——1-五氘代苯基-3-甲基-5-吡唑啉酮(d5-PMP),1,3-二苯基-5-吡唑啉酮(DPP)和1-(4-异丙苯基)-3-甲基-5-吡唑啉酮(PPMP),其中d5-PMP和PPMP为新化合物,其结构经UV,1H NMR,13C NMR,MS及元素分析表征。通过ESI-MS对d5-PMP,DPP及PPMP与乳糖的衍生化性能进行了初步研究。结果表明,d5-PMP和乳糖的反应活性最高,衍生物以双分子标记物为主,衍生化性能与d0-PMP相当;DPP的反应活性最低,单分子和双分子标记物产率相当,不适用于糖类物质的衍生化分析;PPMP的反应活性仅次于d5-PMP或d0-PMP,生成稳定性较好的单分子标记物的倾向较大,优化衍生条件使其定量进行可用于糖类物质分析。     

1-(2-羟甲基-1,3-氧硫杂环戊基)吡啶酮类化合物的合成

研究了1,3-氧硫杂环戊烷核苷类似物的合成. 以吡啶酮为碱基, 利用三甲基硅基三氟甲磺酸酯(TMSOTf)催化, 与1,3-氧硫杂环戊烷发生Vorbruggen缩合反应, 合成了一系列的保护的核苷类似物, 经过进一步脱保护或者还原得到目标产物. 并测试了合成化合物的抗菌活性, 发现该类化合物对革兰氏阳性菌具有中等抑制活性.     

蜂毒肽类似物的合成和生物活性研究

Melittin(GIGAVLKVLTTGLPALISWIKRKRQQ-NH₂)是蜂毒中含26个氨基酸残基的多肽,具有抗菌和溶血等生物活性,是典型的阳离子抗菌肽.本文设计合成了蜂毒肽C端15残基肽片段(GLPALISWIKRKRQQ-NH₂)及其类似物(15残基).研究了Melittin及这些合成肽的抗菌活性、溶血活性、疏水性及二级结构.结果表明,合成的类似物的溶血活性明显降低,抗菌活性基本保留,且与其疏水性相关.类似物中与碱性氨基酸簇(KRKR)距离较远的残基的疏水性对其抗菌活性有较大的贡献.多肽溶血与抗菌机理不同.类似物的抗菌活性和溶血活性与其二级结构(α-螺旋结构)没有明显的相关性.     

利用高效液相色谱鉴定化学合成的 δ-睡眠诱导肽及其类似物

用高效液相色谱对化学方法合成的δ-睡眠诱导肽(DSIP)及其类似物(Tyr~1-DSIP,Phe~5-DSIP以及Tyr~1Phe~5-DSIP)的主要成份进行了分离,应用在线的紫外光谱和萤光光谱检测,并将分离出的色谱峰收集后进行氨基酸分析。     

绿色合成抗癫痫药氯西加酮及其类似物

用温和高效的方法实现了抗癫痫药氯西加酮及其系列类似物的非对映选择性绿色合成.4-甲氧基呋喃酮与芳香醛发生类似Aldol缩合的反应合成系列氯西加酮类似物.通过结晶的方法高选择性地得到(de≥96%)氯西加酮.在反应体系中引入手性诱导试剂实现氯西加酮的非对映选择性合成.所有新化合物的结构都经过1H NMR,13C NMR,IR,HRMS确认.     

噁唑霉素片段的合成

噁唑霉素类化合物(1)是从Streptomyces spp中分离出来的一类抗生素,具有广普和高效的杀菌与抗病毒活性;包括抑制G+菌的生长,抗流感A型病毒和泡疹等.通过逆合成分析,该类化合物可切割为左手片段、中间片段和右手片段(Scheme 1),其中左手片段[1]和中间片段[2]已合成出.这里我们报道的是以L-Serine为起始原料合成右手片段的类似物(Scheme 2).     

新型光活性多羟基氮杂核苷类似物的合成

研究开发新的抗癌、抗病毒药物的有效途径之一是设计、合成以及生物活性评价新型结构的核苷类似物。根据核苷结构的特点,核苷类似物的研究包括碱基改造和糖基改造两个方面。现已报道的糖基结构改造的核苷类似物基本分为含氧杂环、碳环、其它杂环(如:含氮杂环,含硫杂环等)以及无环类似物等⁽¹⁾。由于可利用天然单糖作为原料,获得光活性的含多个手性碳的含氧杂环核苷类似物相对较容易;而其它杂环的光活性核苷类似物,则因涉及至少两个手性碳原子的引入,合成难度增加。本文首次报道了用光活性的苹果酸和酒石酸为起始原料,成功地合成了光活性多羟基氮杂核苷类似物(Ⅰ,Ⅱ)。     

Intramolecularly lactam stapled oxyntomodulin analogues inhibit cancer cell proliferation in vitro

As a glucagon (GCG) receptor (GCGR) and glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) dual agonist, oxyntomodulin (OXM) has been attracting scientific attentions due to its efficacies of suppressing appetite, increasing energy expenditure, and inducing body weight loss in obese humans. Based on the scaffold of native OXM, specific helix-favoring amino acids substitutions and the consequent salt bridge formations were believed to offer enhanced and balanced GCGR/GLP-1R activations through increasing α-helical conformation. Novel OXM analogues are obtained by intramolecular lactam stapling of positions [Glu16 & Lys20] or [Lys17 & Glu21] to further strengthen conformationally constrained stabilization. Even though the lactam staple does not provide additional dual GCGR/GLP-1R activations in vitro, the stapled OXM analogues are firstly reported to have higher or lower anti-PANC-1 cell proliferation activity, meanwhile which has no obvious inhibitory effect on the proliferation of HeLa cells. Therefore, it is speculated that the stapled analogues may have the potential to inhibit the proliferation of specific cancer cell types. Among the stapled peptides as well as their precursors, analogue 6 has the most prominent anti-PANC-1 proliferation activity with the IC₅₀ value of 115.1 μmol/L. Its mechanism of actions including effective signal pathways should be worth further investigations in future.     

Screening and Identification of a Targeting Peptide to nGLP-1R from Phage Display Peptide Library

<正>In order to provide the structure information for designing new exendin-4 analogues,a phage display peptide library was screened by targeting the N-terminal extracellular domain of GLP-1R(nGLP-1R).After four rounds of selection,nine sequences were obtained,four of them have higher affinity for nGLP-1R than the others.We chose two of them named X and Y peptides.Isletβ-cell proliferation assay suggested that X and Y peptides didn't have any activity to increase isletβ-cell proliferation.In other words,X and Y peptides were not agonists to GLP-1R.However, the conservative motifs of X and Y peptides provided us useful information to design new exendin-4 analogues.     

Proteolytic cleavage of glucagon-like peptide-1 by pancreatic beta cells and by fetal calf serum analyzed by mass spectrometry.

Fetal calf serum and a beta-cell line exhibit a proteolytic activity essential for the biological function of glucagon-like peptide-1 (GLP-1). This process of cleavage was investigated using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). To generate processing products, GLP-1 was subjected to rat insulinoma m5F (RINm5F) cell cultures or to fetal calf serum (FCS). For detection of processing products, a standardized extraction method including ion-exchange batch extraction, ultrafiltration, gel filtration, and reversed-phase chromatography was used. The RP fractions were analyzed by MALDI-TOF-MS. Processed proteolytic products were detected by comparing the resulting mass spectra of cell media or FCS after 2 h incubation with GLP-1 (7-36) amide with these of 2 h controls. To perform the comparison of the resulting mass spectra, software (MASSSPECANALYST) based on Microcal Software, Origins C-like language LABTALK was developed. GLP-1 fragments were purified by RP-HPLC, and characterized by sequence analysis. As insulin is the major secretory product of beta cells depending on GLP-1 stimulation, the insulin and insulin fragments of the cell culture supernatants were also analyzed by this method.     

截短胰高血糖素样肽-1的构象研究

截短胰高血糖素样肽-1(sGLP-1)不仅具备刺激胰岛β细胞增生和降低血糖的功能, 而且半衰期较长, 具有非常好的新药开发前景. 为了阐明sGLP-1的功能, 本文运用圆二色光谱和荧光光谱探究了sGLP-1在不同条件下的构象, 结果表明, sGLP-1在磷酸盐缓冲液中主要呈无规则构象, 螺旋含量很低; 在含十二烷基硫酸钠或三氟乙醇的磷酸盐缓冲液中主要呈螺旋构象. 溶液pH值和温度变化对sGLP-1的构象影响显著. sGLP-1保留了结合并激活受体的关键残基, 在受体的诱导下, 在体内形成正确构象, 从而结合并激活受体, 发挥它的功能. 研究结果表明, 适当缩短GLP-1 C端片段, 能获得作用时间长、效力高的GLP-1类似物.     

Preparation of glucagon-like peptide-1 loaded PLGA microspheres: characterizations, release studies and bioactivities in vitro/in vivo

The gut hormone glucagon-like peptide-1 (GLP-1) is proposed for treatment of Type II diabetes mellitus. However, the short half life of GLP-1 in vivo is a major limitation for its application due to the frequent invasive administrations. To provide a optimal formulation to overcome this limitation, we developed a GLP-1 entrapped microspheres to achieve sustained release GLP-1 for 4-week. GLP-1 was stabilized by GLP-1-zinc complexation with zinc carbonate and encapsulated in poly(D,L-lactic-co-glycolic acid) (PLGA) with S/O/O solvent extraction to obtain GLP-1 loaded PLGA microspheres (MS). The characteristics of MS were evaluated as follows: The surface morphology was assessed by scanning electron microscopy (SEM); The drug encapsulation efficiency and GLP-1 controlled release profile was tested by HPLC; The sustained release of GLP-1 MS in vivo and pharmacological efficacy were studied in normal mice and streptozotocin (STZ)-induced diabetic mice model after subcutaneous administration of GLP-1 MS. GLP-1-zinc complexation significantly reduced initial burst release from 37.2 to 7.5%. The controlled release bioactive GLP-1 in vitro was achieved for 4-week period by zinc complexation and addition of ZnCO(3). The optimal and complete cumulative release of GLP-1 from MS was increased from 23 to 63% in 28 d by using low MW PLGA (MW 14000). The in vivo testing in normal mice and diabetic mice suggest that this zinc-stabilized technique combined with S/O/O method in the presence of water insoluble antacid additive ZnCO(3) preserve the biological activity of GLP-1. GLP-1 MS formulation achieved controlled released in vivo for 28 d and exhibit sustained long term pharmacological efficacy to decrease blood glucose level in diabetic mice. This GLP-1 MS formulation provides a practical formulation for long-term sustained delivery of GLP-1 to treat Type II diabetes.     

Glucagon-like peptide 2 (GLP-2), an intestinotrophic mediator

Glucagon-like peptide 2 (GLP-2) is a newly discovered gastrointestinal peptide with 33% sequence homology to glucagon. GLP-2 has attracted interest because of its potent intestinotrophic endocrine/paracrine actions. The peptide, consisting of 33-amino-acid, results from expression of the glucagon gene in the enteroendocrine L-cells of the intestinal mucosa, from where it is released mainly in response to luminal contact with unabsorbed nutrients. In addition to mucosal growth, GLP-2 enhances activities of several intestinal brush-border enzymes, and it delays gastric transit, thereby increasing the intestinal capacity for nutrient absorption. Thus, it appears that GLP-2 serves to ensure an optimal intestinal capacity. The physiological responses following exogenous administration of GLP-2 have been intensely investigated, and these appear to be rather specific for the gut, which is concordant with the localization of the GLP-2 receptor. In addition, treatment with GLP-2 in experimental animal models of several enteropathies indicates that GLP-2 ameliorates most of the observed intestinal abnormalities in these conditions. Following secretion to the blood stream, the intact peptide is degraded rather rapidly by an aminopeptidase. To circumvent the rapid and widespread metabolization of intact GLP-2, degradation-resistant synthetic GLP-2 analogues have been developed together with other approaches, such as inhibition of the GLP-2 degrading enzyme. This is of particular interest with respect to developing GLP-2 into a useful therapeutic agent in conditions with compromised intestinal function, since the first clinical trial has already indicated the potential of GLP-2 treatment in patients with short bowel syndrome.     

Synthesis of Novel 1,3-Dioxolane Nucleoside Analogues

Novel 1,3-dioxolane C-nucleoside analogues of tiazofurin 2-(2-hydroxymethyl-1,3-dioxolan-4-yl)-1,3-thiazole4-carboxamide as well as N-nucleoside analogues of substituted imidazoles 1-(2-hydroxymethyl-1,3-dioxolan4-yl)-4-nitroimidazole and 1-(2-hydroxymethyl-1,3-dioxolan-4-yl)-4,5-dicyanoimidazole were synthesized from methyl acrylate through a multistep procedure. Their structures were confirmed by IR,^1H NMR,^13C NMR spectraand elemental analysis.     

What Is the Mechanism Driving the Reduction of Cardiovascular Events from Glucagon-like Peptide-1 Receptor Agonists?—A Mini Review

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are considered the standard of care for type 2 diabetes in many countries worldwide. These molecules have profound anti-hyperglycaemic actions with a favourable safety profile. They are now being considered for their robust cardiovascular (CV) protective qualities in diabetic patients. Most recent CV outcome trials have reported that GLP-1 RAs reduce major adverse cardiovascular events (MACE). Furthermore, the GLP-1 RAs seem to target the atherosclerotic CV disease processes preferentially. GLP-1 RAs also improve a wide range of routinely measured surrogate markers associated with CV risk. However, mediation analysis suggests these modest improvements may contribute indirectly to the overall anti-atherogenic profile of the molecules but fall short in accounting for the significant reduction in MACE. This review explores the body of literature to understand the possible mechanisms that contribute to the CV protective profile of GLP-1 RAs.     

Highly efficient detection of insulinotropic action of glucagon via GLP-1 receptor in mice pancreatic beta-cell with a novel perfusion microchip

Glucagon exhibits insulinotropic ability by activating cAMP through glucagon or glucagon-like peptide-1(GLP-1) receptors.To investigate the mechanism of endogenous and exogenous glucagon on insulin release,we studied the receptor selectivity on pancreatic islet beta-cells by switching the glucose concentration from 20 mmol/L to 0 mmol/L To measure the exact temporal relationship between glucagon and insulin release,we developed a quick,small volume,multi-channel polydimethylsiloxane(PDMS) microchip.At 0 mmol/L glucose,we observed an insulinotropic effect in both INS-1 cells and islets.Meanwhile,we observed a 63 ± 6.27 s delay of endogenous glucagon-induced insulin release.After treatment with glucagon and GLP-1 receptor antagonists,we found that endogenous glucagon utilized the glucagon receptor,whereas exogenous glucagon primarily utilized the GLP-1 receptor to promote insulin secretion.The microchip can also be used to describe the "glucagonocentric" vision of diabetes pathophysiology.Taken together,the insulinotropic mechanism of different receptors should be taken into account in clinical treatments.