一氧化氮供体偶联的阿司匹林衍生物Ⅱ_6抗血栓作用及其机制研究

目的观察一氧化氮供体偶联的阿司匹林衍生物Ⅱ6对血栓形成的影响,并探讨其作用机制。方法以阿司匹林为对照,观察Ⅱ6经口给药对大鼠下腔静脉血栓和脑血栓形成的影响,采用放射免疫法分析Ⅱ6对大鼠血浆、主动脉条和ECV304细胞上清液中血栓素B2(TXB2)和6-酮-前列腺素F1α(6-Keto-PGF1α)含量的影响,用G riess法测定Ⅱ6对ECV304细胞外液和大鼠血浆中一氧化氮(NO)释放的影响。结果化合物Ⅱ6可减轻实验动物血栓的重量,降低TXB2的生成,提高大鼠血清和ECV304细胞上清液中NO的含量。结论Ⅱ6具有较好的抗血栓作用,其作用机制可能与抑制TXA2的释放,增加NO含量有关。

C族G蛋白偶联受体激活过程

C族G蛋白偶联受体(G protein coupled receptor,GPCR)具有七螺旋跨膜域(heptahelical transmembranedomain,HD)、捕蝇夹域(venusflytrapdomain,VFT)和半胱氨酸富集域(cysteine-rich domain,CRD)等功能域,并在体内组成性形成二聚体。该文介绍C族G蛋白偶联受体激活进程中各功能域的构象变化,以及由此产生的构象学效应。

核酸适体偶联药物的生物偶联构建技术与应用

核酸适体被称为"化学抗体",具有与抗体类似或更加优异的特异性和亲和力,可以精准地靶向靶蛋白,与靶蛋白特异性结合.此外,核酸适体还具有获取简单、合成简便、易于进行化学修饰、不易变性、靶标范围广、免疫原性低及细胞内化快等优点,已被广泛应用于众多研究领域.在癌症治疗领域,核酸适体作为一种优异的靶向识别工具和药物递送载体,可实现抗肿瘤药物的精准递送.将核酸适体与药物分子偶联,可通过核酸适体的靶向作用使药物分子随核酸适体共同进入靶细胞,实现药物分子在靶细胞内的富集,进而促进靶细胞的死亡.近年来,核酸适体偶联药物已成为癌症靶向治疗的前沿新兴领域,希望通过该领域的深入研究为癌症靶向治疗领域提供新思路.本文综合评述了以生物偶联技术构建的核酸适体偶联药物及其应用研究.

抗血管生成因子的多聚体偶联物研究进展

肿瘤血管生成是在已存在的肿瘤血管基础上形成新的毛细血管的过程,是肿瘤发展及转移的重要步骤。因此,应用抑制肿瘤新生血管的药物成为治疗肿瘤的新方法。相对于传统化学治疗药物,尽管抗肿瘤血管生成药物具有更好的安全性,但是此类药物大多都是低分子化合物,其体内药物代谢动力学特征并不理想,半衰期短,清除率高。而通过与聚合物的偶联能有效解决这一难题,与聚合物偶联的抗血管生成因子能直接靶向作用于靶目标蛋白或多肽,这为抗血管生成因子药物的应用提供了光明的前景。

基因治疗中非病毒载体研究进展

肿瘤基因治疗的最大挑战之一是研制安全有效的基因转染载体。在基因转染载体中,非病毒载体以其低毒性、低免疫原性、低致瘤性及易于制备等优点具有良好的应用前景。本文以裸DNA、阳离子脂质体、阳离子多聚物聚乙烯亚胺及壳聚糖、分子偶联体等为代表,从其性质、介导转染的机制、影响转染效率的因素等方面阐述非病毒载体在肿瘤基因治疗方面的研究进展。

A Pd-metalated porous organic polymer as a highly efficient heterogeneous catalyst for C–C couplings

An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Suzuki,Heck and Sonogashira couplings,and afforded the corresponding products while exhibiting excellent activities and selectivities.More importantly,this catalyst can be readily recycled.These features show that such catalysts have significant potential applications in the future.

Endocytosis of adiponectin receptor I through a clathrin- and Rab5-dependent pathway

In eukaryotic cells, receptor endocytosis is a key event regulating signaling transduction. Adiponectin receptors belong to a new receptor family that is distinct from G-protein-coupled receptors and has critical roles in the pathogenesis of diabetes and metabolic syndrome. Here, we analyzed the endocytosis of adiponectin and adiponectin receptor 1 （AdipoR1） and found that they are both internalized into transferrin-positive compartments that follow similar traffic routes. Blocking clathrin-mediated endocytosis by expressing Eps15 mutants or depleting K^＋ trapped AdipoR1 at the plasma membrane, and K^＋ depletion abolished adiponectin internalization, indicating that the endocytosis of AdipoR1 and adiponectin is clathrin-dependent. Depletion of K^＋ and overexpression of Eps15 mutants enhance adiponectin- stimulated AMP-activated protein kinase phosphorylation, suggesting that the endocytosis of AdipoR1 might down-regulate adiponectin signaling. In addition, AdipoR1 colocalizes with the small GTPase Rab5, and a dominant negative Rab5 abrogates AdipoR1 endocytosis. These data indicate that AdipoR1 is internalized through a clathrin- and Rab5- dependent pathway and that endocytosis may play a role in the regulation of adiponectin signaling.

Preparation of Iminodiacetic Acid-Polyethylene Glycol for Immobilized Metal Ion Affinity Partitioning

The synthesis route was investigated and optimized for the preparation of iminodiacetic acid-polyethylene glycol (IDA-PEG) for immobilized metal ion affinity partitioning in aqueous two-phase systems. IDA-PEG was synthesized from PEG in two steps by the reaction of iminodiacetic acid with a monosubstituted derivative of epichlorohydrin-activated PEG. The Cu2+ content combined with IDA-PEG was determined by atomic absorption spectrometry as 0.5 mol·mol^-1 (PEG). Furthermore, the affinity partitioning behavior of lactate dehydrogenase in polyethylene glycol/hydroxypropyl starch aqueous two-phase systems was studied to clarify the affinity effect of the Cu(Ⅱ)-IDA-PEG.

Numerical simulation of fixed bed reactor for oxidative coupling of methane over monolithic catalyst

A three-dimensional geometric model was set up for the oxidative coupling of methane(OCM) fixed bed reactor loaded with Na_3PO_4-Mn/SiO_2/cordierite monolithic catalyst,and an improved Stansch kinetic model was established to calculate the OCM reactions using the computational fluid dynamics method and Fluent software.The simulation conditions were completely the same with the experimental conditions that the volume velocity of the reactant is 80 ml·min^(-1) under standard state,the CH_4/O_2 ratio is 3 and the temperature and pressure is800 ℃ and 1 atm,respectively.The contour of the characteristic parameters in the catalyst bed was analyzed,such as the species mass fractions,temperature,the heat flux on side wall surface,pressure,fluid density and velocity.The results showed that the calculated values matched well with the experimental values on the conversion of CH4 and the selectivity of products(C_2H_6,C_2H_4,CO,CO_2 and H_2) in the reactor outlet with an error range of±4%.The mass fractions of CH_4 and O_2 decreased from 0.600 and 0.400 at the catalyst bed inlet to 0.445 and0.120 at the outlet,where the mass fractions of C_2H_6,C_2H_4,CO and CO_2 were 0.0245,0.0460,0.0537 and 0.116,respectively.Due to the existence of laminar boundary layer,the mass fraction contours of each species bent upwards in the vicinity of the boundary layer.The volume of OCM reaction was changing with the proceeding of reaction,and the total moles of products were greater than reactants.The flow field in the catalyst bed maintained constant temperature and pressure.The fluid density decreased gradually from 2.28 kg·m^(-3) at the inlet of the catalyst bed to 2.18 kg·m^(-3) at the outlet of the catalyst bed,while the average velocity magnitude increased from 0.108 m·s-1 to 0.120 m·s^(-1).

GPCR-CARMA3-NF-kappaB Signaling Axis： A Novel Drug Target for Cancer Therapy

G protein-coupled receptors （GPCRs） play pivotal roles in regulating various cellular functions. It has been well established that GPCR activates NF-κB and aberrant regulation of GPCR-NF-κB signaling axis leads to cancers. However, how GPCRs induce NF-κB activation remains largely elusive. Recently, it has been shown that a novel scaffold protein, CARMA3, is indispensable in GPCR-induced NF-κB activation. In CARMA3-deficient mouse embryonic fibroblast cells, some GPCR ligand-, like lysophosphatidic acid （LPA）, induced NF-κB activation is completely abolished. Mechanistically, upon GPCR activation, CARMA3 is linked to the membrane by β-arrestin 2 and phosphorylated by some PKC isoform. Phosphorylation of CARMA3 unfolds its steric structure and recruits its downstream effectors, which in turn activate the IKK complex and NF-κB. Interestingly, GPCR （LPA）-CARMA3-NF-κB signaling axis also exists in ovarian cancer cells, and knockdown of CARMA3 results in attenuation of ovarian cancer migration and invasion, suggesting a novel target for cancer therapy. In this review, we summarize the biology of CARMA3, discuss the GPCR （LPA）-CARMA3-NF-κB signaling axis in ovarian cancer and speculate its potential role in other types of cancers. With a strongly increasing tendency to identify more LPA-like ligands, such as endothelin-1 and angiotensin II, which also activate NF-κB through CARMA3 and contribute to myriad diseases, GPCR-CARMA3-NF-κB signaling axis is emerging as a novel drug target for various types of cancer and other myriad diseases.

用于肿瘤靶向治疗的前体药物研究进展

常规化疗因特异性差、不良反应大,对肿瘤患者的治疗效果有限。前体药物是一类通过连接子将药物与靶向分子(如抗体、多肽、核酸适体、聚合物等)连接成的药物偶联物,可提高药物向肿瘤部位递送的效率,提高化疗药物的疗效和安全性。本文介绍了几种可用于肿瘤靶向治疗的前体药物,如抗体-药物偶联物、多肽-药物偶联物、核酸适体-药物偶联物和聚合物-药物偶联物,包括其基本组成、靶向递药原理、临床研究进展和上市产品,并分析了前药策略在临床应用中存在的问题,以期为前体药物研发提供参考。

Exploring the specific role of GPCRs dimerization in drug discovery

G-protein-coupled receptors（GPCRs） are G-protein-coupled heptaspanning-membrane receptors.This group has thousands of members and is one of the important drug targets,accounting for 40%-50%of the drugs currently on the market.In the last decade,there has been a substantial re-evaluation of the assumption that GPCRs exist primarily as monomeric polypeptides, with support increasing for a model in which GPCRs can exist as homo- or hetero- dimers or even high-order oligomers.GPCRs dimers are hot research topics.Recent reports suggest that homo- or hetero- dimers exhibit ＂specific＂ functional properties which are distinct from monomeric receptors,involving agonist recognition,signaling,trafficking,and so on.Meanwhile,the occurrence of dimers with different pharmacological and signaling properties opens a completely new field in the search for novel drug targets useful to combat a variety of diseases and with potentially fewer side effects.In this paper,we will mainly review their specific structures and signal transduction,which help us reach for the high-hanging fruits in GPCRs drug discovery.

细菌鞭毛蛋白在Treg表位肽自身免疫性风湿病治疗中的应用前景

用调节性T细胞(Treg)表位肽进行免疫、激发和诱导表位肽特异的Treg细胞,抑制过强的自身免疫应答,从而建立起新的免疫稳态,是一个很有前景的自身免疫性风湿病的治疗方案,然而小分子的表位肽通常很难在体内有效激发出表位肽特异的免疫应答。细菌鞭毛蛋白是固有免疫系统的一种激动剂,在作为偶联载体时对偶联的抗原有极强的佐剂作用,在特定情况下能够激发和诱导Treg细胞。因此,如果将Treg细胞表位肽与细菌鞭毛蛋白共价偶联,偶联体应可通过鞭毛蛋白本身的作用,以及鞭毛蛋白对Treg细胞表位肽的佐剂作用,有效增强基于Treg细胞的免疫应答,从而增强对自身免疫性风湿病的免疫治疗效果。

The calcium sensing receptor: from calcium sensing to signaling

The Ca2+-sensing receptor(the Ca SR),a G-protein-coupled receptor,regulates Ca2+ homeostasis in the body by monitoring extracellular levels of Ca2+([Ca2+]o) and responding to a diverse array of stimuli.Mutations in the Ca2+-sensing receptor result in hypercalcemic or hypocalcemic disorders,such as familial hypocalciuric hypercalcemia,neonatal severe primary hyperparathyroidism,and autosomal dominant hypocalcemic hypercalciuria.Compelling evidence suggests that the Ca SR plays multiple roles extending well beyond not only regulating the level of extracellular Ca2+ in the human body,but also controlling a diverse range of biological processes.In this review,we focus on the structural biology of the Ca SR,the ligand interaction sites as well as their relevance to the disease associated mutations.This systematic summary will provide a comprehensive exploration of how the Ca SR integrates extracellular Ca2+ into intracellular Ca2+ signaling.

In vivo gene expression profiling of the entomopathogenic fungus Beauveria bassiana elucidates its infection stratagems in Anopheles mosquito

The use of entomopathogenic fungi to control mosquitoes is a promising tool for reducing vector-borne disease transmission. To better understand infection stratagems of insect pathogenic fungi, we analyzed the global gene expression profiling of Beauveria bassiana at 36, 60, 84 and 108 h after topical infection of Anopheles stephensi adult mosquitoes using RNA sequencing （RNA-Seq）. A total of 5,354 differentially expressed genes （DEGs） are identified over the course of fungal infection. When the fungus grows on the mosquito cuticle, up-regulated DEGs include adhesion-related genes involved in cuticle attachment, Pthl l-like GPCRs hypothesized to be involved in host recognition, and extracellular enzymes involved in the degradation and penetration of the mosquito cuticle. Once in the mosquito hemocoel, the fungus evades mosquito immune system probably through up-regulating expression of 13-1,3-glucan degrading enzymes and chitin synthesis enzymes for remodeling of cell walls. Moreover, six previous unknown SSCP （small secreted cysteine-rich proteins） are significantly up-regulated, which may serve as ＂effectors＂ to suppress host defense responses. B. bassiana also induces large amounts of antioxidant genes to mitigate host-generated exogenous oxidative stress. At late stage of infection, B. bassiana activates a broad spectrum of genes including nutrient degrading enzymes, some transporters and metabolism pathway components, to exploit mosquito tissues and hemolymph as a nutrient source for hyphal growth. These findings establish an important framework of knowledge for further comprehensive elucidation of fungal pathogenesis and molecular mechanism of Beauveria-mosquito interactions.

Canonical transient receptor potential 4 and its small molecule modulators

Canonical transient receptor potential 4(TRPC4) forms non-selective cation channels that contribute to phospholipase C-dependent Ca2+ entry into cells following stimulation of G protein coupled receptors and receptor tyrosine kinases.Moreover,the channels are regulated by pertussis toxin-sensitive Gi/o proteins,lipids,and various other signaling mechanisms.TRPC4-containing channels participate in the regulation of a variety of physiological functions,including excitability of both gastrointestinal smooth muscles and brain neurons.This review is to present recent advances in the understanding of physiology and development of small molecular modulators of TRPC4 channels.

Skeletal muscle myogenesis is regulated by G protein-coupled receptor kinase 2

G protein-coupled receptor kinase 2 （GRK2） is an important serine/threonine-kinase regulating different membrane receptors and intraceUular proteins. Attenuation of Drosophila Gprk2 in embryos or adult flies induced a defective differentiation of somatic muscles, loss of fibers, and a flightless phenotype. In vertebrates, GRK2 hemizygous mice contained less but more hypertrophied skeletal muscle fibers than wild-type littermates. In C2C12 myoblasts, overexpression of a GRK2 kinase-deficient mutant （K220R） caused precocious differentiation of ceUs into immature myotubes, which were wider in size and contained more fused nuclei, while GRK2 overexpression blunted differentiation. Moreover, p38MAPK and Akt pathways were activated at an earlier stage and to a greater extent in K220R-expressing cells or upon kinase downregulation, while the activation of both kinases was impaired in GRK2-overexpressing cells. The impaired differentiation and fewer fusion events promoted by enhanced GRK2 levels were recapitulated by a p38MAPK mutant, which was able to mimic the inhibitory phosphorylation of p38MAPK by GRK2, whereas the blunted differentiation observed in GRK2-expressing clones was rescued in the presence of a constitutively active upstream stimulator of the p38MAPK pathway. These results suggest that balanced GRK2 function is necessary for a timely and complete myogenic process.

A system for screening agonists targeting β_2-adrenoceptor from Chinese medicinal herbs

In order to develop a model for screening the agonists of human β2-adrenoceptor from Chinese medicinal herbs extracts, we used a cell-based functional assay based on a common G protein-coupled receptor （GPCR） regulation mechanism and destabilized enhanced green fluorescent protein （d2EGFP） reporter gene technique. The positive cell clone was confirmed by real-time polymerase chain reaction （PCR） and imaging analysis. To assess the value of this model, we screened over 2000 high performance liquid chromatography （HPLC）-fractionated samples from the ethanol extracts of Chinese medicinal herbs. Six fractions （isolated from Panax japonicus, Veratrum nigrum, Phellodendron amurense, Fructus Aurantii lmmaturus, Chaenomeles speciosa, and Dictamnus dasycarpus） showed significant effects on active reporter gene expression, three of which （isolated from Phellodendron amurense, Fructus Aurantii lmmaturus, and Chaenomeles speciosa） were selected for further concentration response analysis and the half maximal effective concentration （EC1/2 max） values were 4.2, 2.7, and 4.8 μg/ml, respectively. Therefore, this reporter gene assay was suitable for screening β2-adrenoceptor agonists. The results suggest that the six herbal extracts are the possible agonists of β2-adrenoceptor.

The complexity of G-protein coupled receptor-ligand interactions

The G-protein coupled receptors(GPCRs)play fundamental roles in the human biololgy and drug discovery.GPCRs function as signalling molecules that transduce extracellular signals into cells.The signalling transduction is generally triggered by interacting with ligands,including photons,ions,small organic compounds,peptides,proteins and lipids.In this review,we focus on interactions with diffusible ligands such as hormones and neurotransmitters.We discuss three aspects of the complexity of the GPCR-ligand interactions:functional selectivity of ligands,receptor subtype selectivity of ligands and orphan GPCRs.

Construction of folate-conjugated epirubicin liposomes for enhancing the cellular uptake and the co-localization with nuclei of invasive breast cancer cells

Drug resistance of anthracycline in the invasive cancer is associated with the lowered cellular drug uptake and diminished co-localization of drug with nuclei. In the present study, we aimed to construct the folate-conjugated epirubicin liposomes by incorporating a synthesized folate-lipid derivative; and to assess the effects on cellular drug uptake, co-localization of drug with nuclei and efficacy in treatment of invasive breast cancer cells. The studies were performed on invasive human breast cancer cells. The folate-PEG2ooo-DSPE conjugate was synthesized, and the constructed folate-conjugated epirubicin liposomes were approximately 1 O0 nm in size. The in vitro studies demonstrated that the folate-conjugated epirubicin liposomes had the strongest cellular drug uptake and co-localization with nuclei of the invasive breast cancer cells. Besides, the liposomes displayed the most significant efficacy in killing the invasive cancer cells, in preventing their invasive potential, and in penetrating ability into breast cancer spheroid as well. In conclusion, the constructed folate-conjugated epirubicin liposomes were able to enhance the efficacy in treatment of invasive breast cancer by improving the cellular drug uptake and increasing the co-localization with nuclei, hence offering a new strategy for potentially eradicating the invasive breast cancer cells.