蛋白降解靶向嵌合体临床前及临床研究进展

蛋白降解靶向嵌合体(proteolysis targeting chimera,PROTAC)是一种可以同时结合E3连接酶和靶蛋白的异双功能小分子,能够借助泛素-蛋白酶体系统特异性降解靶蛋白。目前PROTAC药物大多处于临床试验阶段,配体主要为非共价化合物,具有克服耐药性、降解“不可用药”靶蛋白的优势,但非共价配体会使PROTAC产生钩效应(hook effect),影响药效发挥。而共价配体凭借自身优势,可以避免该现象的发生,对于PROTAC的发展具有极大的帮助。本文总结了临床前及临床研究阶段,PROTAC分子在核内蛋白、跨膜蛋白和胞浆蛋白3种蛋白靶点中的应用,并以此为基础进行了讨论与展望,以期为今后PROTAC的发展提供一定的研究思路和参考。     

基于组合药物网络的疾病关联性分析

组合药物在复杂疾病的治疗中形成了多靶点,多环节上的密切联系,对疾病的治疗效果也可达到单种药物治疗意想不到的效果。组合药物中各单药功能各异但联用后治疗效果更佳,说明所对应疾病之间可能存在某种关系。通过研究疾病间关联关系,可能会发现治疗某种疾病的新靶标,从而在新药的研发中取得新的进展。本文以DCDB(组合药物数据库)中的药物组合为数据源构建组合药物网络,并通过网络聚类算法得到了33个独立且内部联系紧密的药物模块。其中7组药物模块所包含的组合药物用于治疗两种或两种以上疾病,说明这些疾病之间存在一定的关联关系。对这些关系进行论证,结果表明,组合药物网络是发现疾病关联关系的一种有效手段。     

蛋白质组学技术在网络药理学中的应用

蛋白质组学发展至今已日趋成熟,在生物医药相关领域研究中的应用显著增加,与之相关的样品制备技术、蛋白定量方法及先进的质谱仪器也得到了快速发展。网络药理学是近年来提出的新药发现新策略,是药理学的新兴分支学科,它从整体的角度探索药物与疾病的关联性,发现药物靶标,指导新药研发。将蛋白质组学技术应用于网络药理学研究,能使研究人员系统地预测和解释药物的作用,加速药物靶点的确认,从而设计多靶点药物或药物组合。综述了蛋白质组学技术的新近研究进展,并简单概述了其在网络药理学中的应用。     

靶向突变p53蛋白的抗肿瘤药物

p53蛋白是人体内十分重要的肿瘤抑制因子,通过调节细胞周期阻滞、诱导细胞凋亡等作用发挥肿瘤抑制功能。突变后的p53蛋白不仅具有显性负性效应（dominant negative effect,DN）抑制野生型p53蛋白功能,而且还通过功能获得性效应（gain of function,GOF）调节细胞代谢、侵袭、迁移等方式促进肿瘤的发生。p53蛋白在超过50%的肿瘤组织中发生突变,是肿瘤细胞区别于正常细胞的一个特异性药物靶点。因此,针对突变p53蛋白开发新型抗癌药物一直是研究的热点。长期以来,由于突变p53蛋白表面较为光滑,缺乏药物结合口袋,使其被认为是一个不可成药的靶点。随着高通量筛选技术的发展以及对突变p53蛋白结构的深入了解,许多靶向突变p53蛋白的小分子化合物被报道并在体外展现出较好的抗肿瘤活性,多款基于突变p53蛋白研发的化合物已经进入临床试验阶段。本文就靶向p53蛋白治疗肿瘤的直接和间接策略进行综述,重点针对突变p53蛋白重激活剂与降解突变p53蛋白的小分子化合物作用机制进行梳理,以期为后续开发靶向突变p53蛋白药物的创新提供帮助。     

β肾上腺素受体与心力衰竭

β肾上腺素受体中的β1和β2亚型是调节心脏功能最重要的两种蛋白。在此将阐述β肾上腺素受体亚型信号转导对心脏的生理功能与心力衰竭的关系,并综合介绍β肾上腺素受体系统中一些关键蛋白的基因多态性与心力衰竭的易感性、预后及药物治疗效果的关联。最后,将探讨如何应用功能选择理论和基因组学发现新的心衰治疗靶点和新药,为新药研发和个体化医疗提供思路。     

基于SVM 的药物靶点预测方法及其应用

目的:基于已知药物靶点和潜在药物靶点蛋白的一级结构相似性,结合SVM技术研究新的有效的药物靶点预测方法。方法:构造训练样本集,提取蛋白质序列的一级结构特征,进行数据预处理,选择最优核函数,优化参数并进行特征选择,训练最优预测模型,检验模型的预测效果。以G蛋白偶联受体家族的蛋白质为预测集,应用建立的最优分类模型对其进行潜在药物靶点挖掘。结果:基于SVM所建立的最优分类模型预测的平均准确率为81.03%。应用最优分类器对构造的G蛋白预测集进行预测,结果发现预测排位在前20的蛋白质中有多个与疾病相关。特别的,其中有两个G蛋白在治疗靶点数据库(TTD)中显示已作为临床试验的药物靶点。结论:基于SVM和蛋白质序列特征的药物靶点预测方法是有效的,应用该方法预测出的潜在药物靶点能够为发现新的药靶提供参考。     

基于质谱的药物蛋白质组学研究

药物蛋白质组学是蛋白质组学技术在药物发现和药物开发过程中的应用。基于质谱的药物蛋白质组学是蛋白质组学的一个分支,在药物研发过程中起了越来越重要的作用。本文就近年来基于质谱的药物蛋白质组学在药物作用机制、药物潜在靶点的筛选及疾病的耐药性机制等研究中取得的进展进行综述。     

降解致病亨廷顿蛋白的新策略

靶向"不可成药靶点"已成为近年原创性药物开发的一个新方向,其中,通过降解致病蛋白是最具前景的方向,目前已有方法主要是PROTAC(proteolysis targeting chimera)等技术。复旦大学鲁伯埙、费义艳及丁澦合作研究团队的最新研究通过基于化合物芯片和前沿光学方法的筛选发现了特异性靶向自噬降低亨廷顿病致病蛋白的小分子化合物,并在小鼠神经元、亨廷顿病病人细胞以及亨廷顿病果蝇模型中得到验证。以上基于自噬小体绑定化合物(autophagosome tethering compounds, ATTEC)的药物研发原创概念有望为亨廷顿病和其他多种疾病的临床治疗提供了切入点。     

RNAi技术研究新进展

RNA干扰(RNAi)是指双链RNA在细胞内特异性地诱导同源互补的mRNA降解,从而阻断相应基因表达的现象。RNAi在生物界中广泛存在,其发生过程主要分为3个阶段:起始阶段、扩增阶段和效应阶段。它在维持基因组稳定、基因表达调控等方面发挥重要生物学作用。随着人们对RNAi研究的不断深入,目前RNA干扰技术作为基因沉默的一个工具,已被广泛用于基因功能研究、疾病的靶点治疗和寻找新的药物靶标等方面的研究。     

靶向蛋白质泛素修饰及降解在前列腺癌治疗中的机遇与挑战

前列腺癌是中国发病率增长最快的男性肿瘤,抗雄激素治疗耐药是导致前列腺癌患者预后差的主要原因。因此,解决耐药性难题是前列腺癌转化研究的关键问题。哺乳动物细胞利用泛素-蛋白酶体系统实现蛋白质的靶向降解。因此,前列腺癌中关键的癌基因如雄激素受体（AR）的上游泛素化调控因子（如去泛素化酶）是潜在的治疗靶点。然而,这些酶具有较广的底物谱系,存在脱靶的可能性。近来,基于泛素-蛋白酶体系统开发的蛋白质降解靶向嵌合体（proteolysis-targeting chimeras,PROTAC）技术是最具前景和革命性的新型抗癌药物研发技术,能够利用特定E3泛素连接酶对靶蛋白进行降解而不影响其他底物。与传统小分子抑制剂相比,PROTAC分子在克服耐药性以及针对不可成药的靶点方面拥有巨大优势。目前,针对AR的PROTAC降解剂已在II期临床取得了成功,靶向蛋白质泛素化及降解途径的新技术将有望为前列腺癌的临床治疗带来新的突破。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.     

Enterovirus 71 3C proteolytically processes the histone H3 N-terminal tail during infection

Highlights
1. The N-terminal tail of histone H3 is specifically cleaved during EV71 infection.
2. Viral protease 3C is identified as a protease responsible for proteolytically processing the N-terminal H3 tail.
3. Our finding reveals a new epigenetic regulatory mechanism for Enterovirus 71 in virus-host interactions.     

Detection of EBV and HHV6 in the Brain Tissue of Patients with Rasmussen’s Encephalitis

Rasmussen’s encephalitis (RE) is a rare pediatric neurological disorder, and the exact etiology is not clear. Viral infection may be involved in the pathogenesis of RE, but conflicting results have reported. In this study, we evaluated the expression of both Epstein-Barr virus (EBV) and human herpes virus (HHV) 6 antigens in brain sections from 30 patients with RE and 16 control individuals by immunohistochemistry. In the RE group, EBV and HHV6 antigens were detected in 56.7% (17/30) and 50% (15/30) of individuals, respectively. In contrast, no detectable EBV and HHV6 antigen expression was found in brain tissues of the control group. The co-expression of EBV and HHV6 was detected in 20.0% (6/30) of individuals. In particular, a 4-year-old boy had a typical clinical course, including a medical history of viral encephalitis, intractable epilepsy, and hemispheric atrophy. The co-expression of EBV and HHV6 was detected in neurons and astrocytes in the brain tissue, accompanied by a high frequency of CD8⁺ T cells. Our results suggest that EBV and HHV6 infection and the activation of CD8⁺ T cells are involved in the pathogenesis of RE.     

Perinatal Vertical Transmission of Chikungunya Virus in Ruili,a Town on the Border between China and Myanmar

正Dear Editor,Chikungunya virus (CHIKV), an arbovirus in the family of Togaviridae, genus Alphavirus, is transmitted by the A.aegyptii or A. albopictus mosquito, and causes disease in humans characterized by fever, rash, and arthralgia (Silva and Dermody 2017; Suhrbier 2019). It was first reported in 1953 in Tanzania, and caused only a few outbreaks and sporadic cases in Africa and Asia in last century. However, in the epidemic in 2004, CHIKV acquired mutations that conferred enhanced transmission by the A. albopictus mosquito(Schuffenecker et al. 2006). Since then, it has successively caused outbreaks in Africa, the Indian Ocean, South East Asia, the South America, and Europe (Zeller et al. 2016).     

Development of a Novel Reverse Transcription Loop-Mediated Isothermal Amplification Method for Rapid Detection of SARS-CoV-2

In conclusion, the novel visual RT-LAMP assay is a simple, rapid, and sensitive approach for detection of SARS-CoV-2, and it is ready for application in primary care and community hospitals or health care centers, and even patients' own houses in response to the current SARS-CoV-2 epidemic because the assay does not require sophisticated equipment and skilled personnel. Furthermore, it is also ready to be used in fields for screening samples from wild animals and environments to facilitate the identification of potential intermediate hosts that mediate the cross-species transmission of SARS-CoV-2 from bats to humans.