新型M5胆碱受体选择性拮抗剂的发现及药理活性研究

目的:选择性拮抗M5胆碱受体可成为治疗药物成瘾的新途径,本文旨在利用虚拟筛选、结构优化、分子与细胞水平的药理活性评价,以期获得新型M5胆碱受体选择性拮抗剂.方法:通过虚拟筛选获得具有新型骨架的候选化合物,以该结构为基础进行结构优化;利用放射配基实验对系列化合物进行活性测定;进一步评价其亲和力对各胆碱受体亚型的选择性,并...     

Aβ寡聚体调控M1胆碱受体下游信号转导通路的机制研究

摘要 目的：阿尔茨海默病（Alzheimer''s disease, AD）病理状态下M1胆碱受体功能受损,无法对配体做出正确响应。本研究模拟AD早期Aβ寡聚体富集的病理状态,考察对M1胆碱受体下游信号通路关键分子活性的影响,以期为AD病理状态下M1胆碱受体信号偶联障碍机制提供新的见解。方法：制备Aβ寡聚体（Aβ oligomers, AβOs）,1 μM AβOs预处理CHO-M1细胞30 min、24 h和48 h,加入胆碱受体激动剂乙酰胆碱或者卡巴胆碱激活M1胆碱受体,利用Ca²⁺检测实验、IP-One-Gq KIT检测实验及Western blot实验检测受体激动后下游关键信号分子Ca²⁺、IP1的释放量以及ERK磷酸化的动态变化。结果：AβOs预处理导致激活细胞内M1胆碱受体其下游Ca²⁺和IP1的释放量减少、ERK被更快激活。结论：AβOs预处理导致激活M1胆碱受体下游关键信号分子释放水平、磷酸化水平异常,揭示在阿尔茨海默病早期M1胆碱受体便出现功能障碍,无法正确激活信号转导通路。     

M1毒蕈碱乙酰胆碱受体同源建模模板的选取及验证

目的:探讨不同同源模板所获得M1毒蕈碱乙酰胆碱受体模型的合理性及可靠性。方法:以牛视紫红素受体、人源β2-肾上腺素受体、M2胆碱受体和M3胆碱受体为模板,分别对M1胆碱受体进行同源建模;采用分子对接获得各M1胆碱受体同源模板与配体的互作模式,并与已报道的M胆碱受体晶体结构进行静态比对,得到最佳M1胆碱受体同源模板;采用分子动力学模拟分析配体与关键残基距离的变化,对M1胆碱受体同源模板进行动态验证。结果:M2胆碱受体与M1胆碱受体的序列相似度较高,为67.9%;以Inactive M2胆碱受体为模板构建的M1胆碱受体(M1R_(inactive-M2R))与其他晶体结构间RMSD值的均值最低,为1.39;M1R_(inactive-M2R)别构位点K392及E397残基侧链与结合口袋距离更近,与配体结合构象更匹配;分子对接结果显示,双位点别构激动剂VU0184670与M1R_(inactive-M2R)别构结合位点Y85、Y381的距离分别为4.8、6.8,优于其他模型;分子动力学模拟后,配体与Q177残基的距离由7.4降至2.9,提示配体VU0184670向Q177方向偏转,与文献结果一致。结论:以Inactive M2受体结构为模板构建的M1胆碱受体模型最为合理,更接近M1胆碱受体的晶体结构。本研究为M1胆碱受体药物开发提供重要工具,为其他GPCRs受体同源建模提供创新范式。     

脂蛋白受体激动剂调节COPD小鼠炎症反应机制研究

目的:探究脂蛋白受体激动剂BML-111调节COPD小鼠炎症反应的机制.方法:构建COPD小鼠模型,通过HE染色检测小鼠肺组织和血管周围炎性细胞侵润程度;通过ELISA检测小鼠支气管肺泡灌洗液(BALF)中TGF-β、TNF-d、IL-1β和IL-10的含量;通过Western blot检测小鼠肺组织中NLRP3、Cl...     

靶向FLT3的抗肿瘤小分子抑制剂的虚拟筛选

摘要 目的：本研究旨在利用虚拟筛选技术,从ChEMBL数据库中发现新型FLT3抑制剂,为靶向FLT3的小分子抑制剂的开发提供理论基础。方法：选取ChEMBL数据库中约240万个小分子作为数据集,以FLT3蛋白为靶标,通过分子对接进行虚拟筛选,对筛选得到的目标化合物进行200 ns的分子动力学模拟,研究其与FLT3蛋白之间的结合能力和稳定性。结果：通过虚筛选成功发现了5个未见文献报道的新型潜在FLT3抑制剂（ChEMBL ID: 5186572、4845881、2151842、3642822、3916042）,对接分数（-10.93 ~ -12.58）和结合自由能（-82.06 ~ -88.49 kcal/mol）均优于参照组Gilteritinib（-8.73和-65.38 kcal/mol）;分子动力学模拟结果显示,目标化合物与FLT3蛋白均具有较强的结合能力,且与FLT3蛋白形成的复合物具有良好的稳定性。结论：本研究利用虚拟筛选技术成功发现了5个未见文献报道的具有潜在抗肿瘤活性的FLT3抑制剂,为新一代FLT3抑制剂的研发提供了重要的理论基础。     

低心血管疾病风险选择性环氧合酶-2抑制剂的虚拟筛选

摘要 目的：寻找具有血栓素A2受体（Thromboxane A2 receptor,TP）抑制作用的选择性环氧合酶-2（Cyclooxygenase-2,COX-2）抑制剂,以期降低其心血管疾病风险。方法：本研究从公开数据库中获取了512种TP抑制剂,通过分子对接、分子动力学模拟和ADMET预测,筛选出化合物TP84。结果：分子对接结果显示,与先前获批的选择性COX-2抑制剂罗非昔布相比,TP84对COX-2的亲和力更高,对环氧合酶-1（Cyclooxygenase-1,COX-1）的亲和力更低;分子动力学模拟进一步表明,模拟过程中TP84与COX-1的结合不稳定,而TP84能稳定结合COX-2,与COX-2的结合自由能是COX-1的3倍;此外,根据ADMET预测,TP84的药物化学、吸收、分布、代谢、排泄和毒性处于类药物候选物的可接受范围内。结论：TP84是一种潜在的低心血管疾病风险选择性COX-2抑制剂。     

选择性雌激素受体β激动剂对子宫腺肌病模型小鼠孕激素受体和胰岛素样生长因子-1的影响

摘要 目的：探讨选择性雌激素β受体（Estrogen Receptor beta,ERβ）激动剂对子宫腺肌病模型小鼠孕激素受体和胰岛素样生长因子-1的影响。方法：子宫腺肌病小鼠(n=30)随机平分为三组-模型组、孕三烯酮组与选择性ERβ激动剂组。模型组每日灌胃蒸馏水0.4 mL/20 g体重,孕三烯酮组每日灌胃孕三烯酮水溶液0.008 mg/20 g体重,选择性ERβ激动剂组每日灌胃WAY-32255水溶液0.008 mg/20 g体重,连续口服14 d。结果：孕三烯酮组与选择性ERβ激动剂组治疗第7 d与第14 d的小鼠体重高于模型组（P<0.05）,选择性ERβ激动剂组高于孕三烯酮组（P<0.05）。孕三烯酮组与选择性ERβ激动剂组治疗第7 d与第14 d的子宫病理评分低于模型组（P<0.05）,选择性ERβ激动剂组低于孕三烯酮组（P<0.05）。孕三烯酮组与选择性ERβ激动剂组治疗第7 d与第14 d的血清孕激素受体（Progesterone receptor,PR）和胰岛素样生长因子（insulin like growth factor,IGF-1）含量低于模型组（P<0.05）,选择性ERβ激动剂组低于孕三烯酮组（P<0.05）。孕三烯酮组与选择性ERβ激动剂组治疗第7 d与第14 d的子宫RhoA和ROCK蛋白相对表达水平低于模型组（P<0.05）,选择性ERβ激动剂组低于孕三烯酮组（P<0.05）。结论：选择性ERβ激动剂对子宫腺肌病模型小鼠的应用能抑制血清PR和IGF-1的释放,降低RhoA和ROCK蛋白的表达,从而能改善子宫病理状况,提高小鼠体重。     

人蛋白酶体亚基PSMB1的重组表达、纯化及在蛋白酶体抑制剂体外筛选中的应用

蛋白酶体是真核细胞中的一类多亚基蛋白酶复合物,它在胞内蛋白质降解的泛素-蛋白酶体通路中起关键作用。重组表达蛋白酶体的活性亚基可以用于在体外筛选、寻找具有蛋白酶体抑制剂作用的化合物。将人蛋白酶体催化亚基(PSMB1)cDNA的编码区(全长726 bp)克隆至原核表达载体pET28a(+),构建重组质粒pET28a-PSMB1,转化大肠杆菌BL21(DE3),通过1 mmol/L IPTG,20℃过夜诱导,获得相对分子量约为27 kDa的重组蛋白,采用IMAC亲和层析柱纯化重组蛋白,纯化后的重组蛋白纯度超过95%。重组蛋白酶解后经NanoLC-MS/MS鉴定表明所表达的融合蛋白氨基酸序列完全正确。在体外BIAcore分析中,重组蛋白表现出对不同化合物的选择性结合能力,其中与蛋白酶体抑制剂雷公藤红素的结合较强,10μmol/L的雷公藤红素与重组蛋白的结合达到27 RU,并且具有良好的浓度依赖型。本研究建立了表达、纯化人蛋白酶体催化亚基PSMB1的方法,并应用于具有蛋白酶体抑制活性化合物的体外筛选。     

BRCA1相关蛋白1对肾癌增殖和侵袭的实验研究

目的:研究BRCA1相关蛋白(BRCA1-associated protein-1,BAP1)对肾癌细胞增殖和侵袭的影响。方法:通过含有不同BAP1和HAT1载体的慢病毒感染后用嘌呤霉素筛选的方法在肾癌细胞系中构建BAP1稳定低表达、HAT1稳定高表达、HAT1稳定低表达以及BAP1低表达且HAT1低表达的慢病毒细胞稳转株。通过WB和PCR验证BAP1在肾癌细胞系中对于HAT1的调控。使用CCK-8细胞增殖和TRANSWELL侵袭实验检测对于肾癌细胞增殖和侵袭能力的影响。利用免疫组化和临床回访数据分析其临床意义。结果:肾癌细胞系中BAP1表达降低后HAT1表达升高。BAP1低表达部分通过了HAT1表达升高促进肾癌的增殖和侵袭能力。在肾癌组织中BAP1的表达与HAT1表达具有相关性(P0.05)。结论:BAP1敲低的肾癌细胞中HAT1特异性的高表达可能是导致肾癌细胞增殖和侵袭能力增强的原因。BAP1与HAT1在肾癌组织中的表达具有显著相关性。     

腺苷受体激动剂对心肌缺血再灌注损伤大鼠内质网应激的影响及其作用机制研究

目的:探讨腺苷受体激动剂对心肌缺血再灌注损伤(MIRI)大鼠内质网应激(ERS)的影响及其作用机制。方法:选取雄性成年Wistar大鼠56只,利用Langendorff装置制成大鼠离体心脏MIRI模型。随机分为四组(n=14):假手术组(Sham组)、心肌缺血再灌注组(MIRI组)、腺苷受体激动剂组(NECA组)和内质网应激抑制剂组(TUDCA组)。利用透射电镜观察四组心肌超微结构的变化;免疫组化观察心肌肌醇依赖酶1α(IRE1α)的表达情况;Western blot方法检测心肌ERS中IRE1-XBP1信号通路标志蛋白IRE1α、X盒结合蛋白1s(XBP1s)的表达水平;TUNEL检测心肌细胞凋亡情况。结果:透射电镜结果显示,Sham组肌丝排列规则致密,嵴排列整齐,外膜和肌节形态完整;MIRI组大部分肌丝断裂,肌节挛缩变形,嵴排列稀疏结构破坏,间隙增宽,可见线粒体空泡变性;NECA组及TUDCA组较MIRI组损伤减轻,内质网轻度扩张或者正常,肌丝排列较整齐。免疫组化结果发现,Sham组心肌纤维呈细长圆柱形,形态正常,少量结缔组织存在,基本无IRE1α阳性染色;MIRI组细胞排列紊乱,有许多断裂的细胞出现,IRE1α阳性染色区域显著增加,而NECA和TUDCA组细胞病理的变化较轻,相对于MIRI组,IRE1α阳性染色部位明显减少。Western blot结果显示,与Sham组相比,MIRI组的IRE1α和XBP1s蛋白的表达水平明显上升(P0.05);而与MIRI组相比,TUDCA组及NECA组IRE1α和XBP1s的蛋白表达水平显著降低(P0.05)。TUNEL结果显示,MIRI组细胞凋亡明显,Sham组基本没有发生心肌细胞凋亡,MIRI组较NECA组及TUDCA组的凋亡细胞数更多。结论:NECA可通过抑制IRE1-XBP1信号通路来减轻ERS反应,达到保护心肌组织细胞的目的。     

Discovery,synthesis, and structure–activity relationships of 2-aminoquinazoline derivatives as a novel class of metabotropic glutamate receptor 5 negative allosteric modulators

A virtual screening approach using various in silico methodologies led to the discovery of 2-(m-tolylamino)-7,8-dihydroquinazolin-5(6H)-one (1) as a moderately active negative allosteric modulator (NAM) of the metabotropic glutamate receptor subtype 5 (mGluR5) showing high selectivity against the subtype mGluR1. Modifications of the parent compound by rational design yielded a series of highly potent derivatives which will serve as valuable starting points for further hit-to-lead optimization efforts toward a suitable drug candidate for the treatment of l-DOPA induced dyskinesia.     

Structure and Dynamics of Double Helical DNA in Torsion Angle Hyperspace: A Molecular Mechanics Approach

Abstract

Analysis of the conformational space populated by the torsion angles and the correlation between the conformational energy and the sequence of DNA are important for fully understanding DNA structure and function. Presence of seven variable torsion angles about single covalent bonds in DNA main chain puts a big challenge for such analysis. We have carried out restrained energy minimization studies for four representative dinucleosides, namely d(ApA):d(TpT), d(CpG):d(CpG), d(GpC):d(GpC) and d(CpA):d(TpG) to determine the energy hyperspace of DNA in context to the values of the torsion angles and the structural properties of the DNA conformations populating the favorable regions of this energy hyperspace. The torsion angles were manipulated by constraining their values at the reference points and then performing energy minimization. The energy minima obtained on the potential energy contour plots mostly correspond to the conformations populated in crystal structures of DNA. Some novel favorable conformations that are not present in crystal structure data are also found. The plots also suggest few low energy routes for conformational transitions or the associated energy barrier heights. Analyses of base pairing and stacking possibility reveal structural changes accompanying these transitions as well as the flexibility of different base steps towards variations in different torsion angles.     

Asymmetric synthesis of the four diastereoisomers of a novel non-steroidal farnesoid X receptor (FXR) agonist: Role of the chirality on the biological activity

An asymmetric synthetic strategy was designed for the preparation of the four possible diastereoisomers of 3,6-dimethyl-1-(2-methylphenyl)-4-(4-phenoxyphenyl)-4,8-dihydro-1H-pyrazolo[3,4-e][1,4]thiazepin-7-one, a non-steroidal FXR agonist, we recently discovered following a virtual screening approach. The results obtained from an AlphaScreen assay clearly demonstrated that only the isomer endowed with 4R,6S absolute configuration is responsible for the biological activity. A deep investigation of the different putative binding modes adopted by these enantiomerically pure ligands using computational modeling studies confirmed the enantioselectivity of FXR towards this class of molecules.     

Discovery,design and synthesis of a selective S1P3 receptor allosteric agonist

Potent and selective S1P₃ receptor (S1P₃-R) agonists may represent important proof-of-principle tools used to clarify the receptor biological function and assess the therapeutic potential of the S1P₃-R in cardiovascular, inflammatory and pulmonary diseases. N,N-Dicyclohexyl-5-propylisoxazole-3-carboxamide was identified by a high-throughput screening of MLSMR library as a promising S1P₃-R agonist. Rational chemical modifications of the hit allowed the identification of N,N-dicyclohexyl-5-cyclopropylisoxazole-3-carboxamide, a S1P₃-R agonist endowed with submicromolar activity and exquisite selectivity over the remaining S1P_1,2,4,5-R family members. A combination of ligand competition, site-directed mutagenesis and molecular modeling studies showed that the N,N-dicyclohexyl-5-cyclopropylisoxazole-3-carboxamide is an allosteric agonist and binds to the S1P₃-R in a manner that does not disrupt the S1P₃-R–S1P binding. The lead molecule herein disclosed constitutes a valuable pharmacological tool to explore the molecular basis of the receptor function, and provides the bases for further rational design of more potent and drug-like S1P₃-R allosteric agonists.     

Discovery of evocalcet,a next-generation calcium-sensing receptor agonist for the treatment of hyperparathyroidism

The calcium-sensing receptor (CaSR) plays an important role in sensing extracellular calcium ions and regulating parathyroid hormone secretion by parathyroid gland cells, and the receptor is a suitable target for the treatment of hyperparathyroidism. Cinacalcet hydrochloride is a representative CaSR agonist which widely used for the hyperparathyroidism. However, it has several issues to clinical use, such as nausea/vomiting and strong inhibition of CYP2D6. We tried to improve these issues of cinacalcet for a new pharmaceutical agent as a preferable CaSR agonist. Optimization from cinacalcet resulted in the identification of pyrrolidine compounds and successfully led to the discovery of evocalcet as an oral allosteric CaSR agonist. Evocalcet, which exhibited highly favorable profiles such as CaSR agonistic activity and good DMPK profiles, will provide a novel therapeutic option for secondary hyperparathyroidism.     

Development of a highly selective, orally bioavailable and CNS penetrant M1 agonist derived from the MLPCN probe ML071

Herein we report the discovery and SAR of a novel series of M(1) agonists based on the MLPCN probe, ML071. From this, VU0364572 emerged as a potent, orally bioavailable and CNS penetrant M(1) agonist with high selectivity, clean ancillary pharmacology and enantiospecific activity.     

体外培养牛白细胞中环形泰勒焦虫(Theileria annulata)的增殖、释放与感染

在体外培养的牛外周血白细胞中,环形泰勒焦虫裂殖子与裂殖体寄生于宿主细胞的细胞质中,并且随着宿主细胞的分裂而分到两个子细胞中。焦虫染色质粒的分裂方式为二分裂,随着焦虫颗粒的不断增殖,逐渐发育为成熟的裂殖体。体外培养感染焦虫的牛白细胞可通过伪足与细胞裂解两种途径向培养液中释放焦虫颗粒。释放到培养液中的焦虫颗粒对体外培养的健康牛外周血白细胞具有感染能力,感染细胞能在体外连续传代培养。     

感染环形泰勒焦虫(Theileria annulata)的牛外周血白细胞的形态观察

用光镜及扫描电镜观察了体外高代培养的含牛焦虫颗粒的牛外周血白细胞的形态及在细胞周期中细胞表面的特征性变化。这种经多年传代的含虫的牛外周血白细胞恢复了分裂和繁殖的能力,目前已成为较稳定的细胞系。细胞表面具多种伪足突起,如叶状、丝状及绒毛状。细胞周期中备期细胞表面的主要特征是:S期:细胞平扁,边缘具薄的时状伪足及丝状伪足;G_2期:细胞中部隆起,表面具少量绒毛状伪足;G_1期:绒毛状结构少或无,而出现丝状及小的叶状伪足,细胞仍保持球形;M期:细胞球形,表面密被以绒毛。作者根据扫描电镜的观察认为光镜下所观察的两类细胞,实际上是反映了一种细胞处于不同发育阶段时的特征。