外泌体在肝癌微环境通讯中的作用

外泌体是由细胞分泌的纳米级(30～150 nm)囊泡结构,是生物活性物质的载体。外泌体中富含蛋白质、脂质和多种核酸(如miRNA、lncRNA和mtDNA等),其能将这些活性物质由供体细胞运送至靶细胞,从而调控后者的生命活动。原发性肝细胞癌是最为常见的恶性肿瘤之一,在我国有着极高的发病率和死亡率。由于起病隐匿且易转移易复发等特点,肝癌的早期诊断和有效治疗一直难以实现。外泌体与肝癌密切相关。研究发现,外泌体作为肝癌微环境中活性物质的载体,在肝癌的增殖、转移和耐药等方面发挥重要的通讯作用。此外,血液中的外泌体是液体活检的理想材料,在肝癌的诊断与治疗方面有重要意义。本文旨在对目前外泌体在肝癌微环境通讯中的作用做简要综述,为后续基础研究与临床应用提供理论依据。     

外泌体miR-145和miR-21在非小细胞肺癌中的研究进展

非小细胞肺癌(non-small cell lung cancer,NSCLC)是全球发病率最高的恶性肿瘤之一,大多数患者在确诊时已是中晚期,预后极差。外泌体是细胞主动分泌的直径为40～100 nm的膜小体,包含丰富的蛋白质、microRNAs(miRNAs)等物质,参与细胞间的物质交换和信息交流。非小细胞肺癌源性的外泌体miRNA参与调节肿瘤细胞的发生发展、侵袭及转移等过程,在肿瘤细胞的生理、病理过程中扮演了重要角色。本文将系统阐述外泌体的生物学特性、生物学功能以及外泌体miR-145和miR-21在调控非小细胞肺癌进展、早期诊断、治疗靶点筛选及预后中的作用,为外泌体miRNA基础研究与临床应用提供参考。     

外泌体及其在神经退行性疾病发生、发展和诊治中的作用

外泌体是一种直径在30～100 nm的细胞外膜性囊泡,由真核生物体内的多种细胞产生,其内含有蛋白质、脂质、核酸以及和起源细胞相关的物质等。外泌体能够携带起源细胞内成分并作用于邻近或远距离的细胞,从而实现生理及疾病状态下不同细胞间的信息交流。近年来,研究表明神经退行性疾病发病相关的错误折叠蛋白(如α-突触核蛋白、tau蛋白、β-淀粉样蛋白等)能够通过外泌体运输,从而促进这些蛋白在细胞间传播并传播至未病变区域,加快疾病进程。本综述着重阐述了外泌体的起源和组成、生物合成、分泌、功能,尤其是在神经退行性疾病发生和发展中的作用。除此之外,还探讨了外泌体作为生物标记物和药物传递载体在神经退行性疾病的诊断与治疗中的作用和前景。     

外泌体介导长链非编码RNA H19促进肝癌细胞增殖与转移

外泌体是由细胞分泌的直径为30～150 nm的小囊泡,含有丰富的mRNA、microRNA和长链非编码RNA(lncRNA)。目前,大多数外泌体研究都集中在mRNA和microRNA,而对lncRNA的生物学功能并不十分清楚。研究表明,肿瘤细胞外泌体 lncRNA H19在肿瘤细胞的增殖、迁移和侵袭中发挥了重要作用。本研究将筛选到的lncRNA H19高表达的肝癌细胞HCCLM3,分别收集其高表达lncRNA H19的外泌体和其下调lncRNA H19表达后的外泌体。然后,将收集到的外泌体分别添加到lncRNA H19低表达的肝癌细胞Hep3B和HepG2孵育液中。孵育24 h后,检测其对肿瘤细胞的增殖、迁移和侵袭能力的影响。结果显示,肝癌细胞HCCLM3可分泌大量的外泌体,且能被其他肿瘤细胞大量摄取;与下调lncRNA H19表达的外泌体相比,lncRNA H19高表达的外泌体能显著增强Hep3B和HepG2细胞的增殖、迁移和侵袭能力。而这一作用可通过激活PI3K/AKT/mTOR通路实现。上述结果表明,lncRNA H19高表达的肝癌细胞以外泌体方式,增强邻近肝癌细胞的增殖、迁移和侵袭能力,促进肝癌的发生与发展。     

外泌体介导的长链非编码RNA H19促进肝癌细胞的增殖与转移

外泌体是由细胞分泌的直径为30～150 nm的小囊泡,含有丰富的mRNA、microRNA和长链非编码RNA(lncRNA)。目前,大多数外泌体研究都集中在mRNA和microRNA,而对lncRNA的生物学功能并不十分清楚。研究表明,肿瘤细胞外泌体lncRNA H19在肿瘤细胞的增殖、迁移和侵袭中发挥了重要作用。本研究将筛选到的lncRNA H19高表达的肝癌细胞HCCLM3,分别收集其高表达lncRNA H19的外泌体和其下调lncRNA H19表达后的外泌体。然后,将收集到的外泌体分别添加到lncRNA H19低表达的肝癌细胞Hep3B和HepG2孵育液中。孵育24 h后,检测其对肿瘤细胞的增殖、迁移和侵袭能力的影响。结果显示,肝癌细胞HCCLM3可分泌大量的外泌体,且能被其他肿瘤细胞大量摄取;与下调lncRNA H19表达的外泌体相比,lncRNA H19高表达的外泌体能显著增强Hep3B和HepG2细胞的增殖、迁移和侵袭能力。而这一作用可通过激活PI3K/AKT/mTOR通路实现。上述结果表明,lncRNA H19高表达的肝癌细胞以外泌体方式,增强邻近肝癌细胞的增殖、迁移和侵袭能力,促进肝癌的发生与发展。     

EB病毒感染相关外泌体的研究进展

外泌体(exosome)是由机体多种细胞释放的一种纳米级膜性小囊泡,包含母细胞来源的蛋白质、脂质以及核酸等物质,参与细胞间的信号传递,在疾病的发生、发展中起着重要作用。EB病毒(epstein-barr virus,EBV)是一种嗜人类淋巴细胞的双链DNA疱疹病毒。研究证实EBV感染的细胞分泌外泌体,其携带有EBV编码的功能性蛋白和核酸等多种生物活性分子,且这些生物活性分子在EBV感染相关疾病的发生、诊断及治疗中具有重要意义。现就近年来EBV感染相关外泌体中蛋白和核酸等方面的研究现状作一概述。     

正常与氧糖剥夺再复氧培养的星形胶质细胞来源外泌体miRNA测序分析

本研究通过高通量测序技术,分析正常培养和氧糖剥夺再复氧(oxygen and glucose deprivation/reoxygenation,OGD/R)培养星形胶质细胞来源外泌体的差异微小RNA(microRNA,miRNA)。采用超速离心法提取正常组和OGD/R组星形胶质细胞培养基上清的外泌体,透射电镜观察到提取的外泌体呈典型囊泡状,包膜完整,含有低电子密度的物质;纳米颗粒追踪技术(NTA)检测到星形胶质细胞外泌体大小为100.5±31.1 nm,占比为 96.8%;免疫印迹检测显示,提取物中有外泌体标志性蛋白肿瘤易感蛋白(tumour-susceptibility protein, TSG101)、热休克蛋白60 (heat shock proteins 60, Hsp60)、ALG-2相互作用蛋白X(ALG-2-interacting protein X, ALIX)的表达。与正常组相比,OGD/R组共有41个miRNA发生显著改变,其中20个miRNA显著升高,21个miRNA显著降低(P<0.05)。基因本体功能(GO)分析显示,差异靶基因主要参与蛋白质糖基化、脂质代谢过程、磷酸化作用、高尔基体、内质网、内吞体、细胞质囊泡和细胞突起等生物学过程;京都基因与基因组百科全书(KEGG)通路分析发现,差异靶基因主要与丁酸代谢、β-丙氨酸代谢、脂肪酸降解、线粒体自噬和P53信号通路等代谢途径和信号通路有关。通过对正常组和OGD/R组的星形胶质细胞来源的外泌体miRNA测序并进一步施行靶基因功能富集分析,为后续研究星形胶质细胞外泌体对氧糖剥夺再灌注神经元发挥的保护作用的具体机制提供了一定的研究基础。     

外泌体在肿瘤转移及诊疗中的研究进展

外泌体是直径为40~130 nm的纳米级囊泡结构,其中包含有大量的蛋白质、核酸和脂质等,在细胞间物质信息传递过程中发挥重要的作用。与正常细胞相比,肿瘤细胞释放更多的外泌体,并且其中所包含的一系列蛋白质和核酸组分(包括mi RNAs)在调节肿瘤微环境、促进肿瘤的转移侵袭过程中起到了关键的作用。该文重点介绍了由外泌体所介导的整合蛋白、表皮生长因子受体和mi RNAs等分子在细胞间的转运对于肿瘤转移和侵袭的影响,并展望了外泌体在肿瘤的诊断和治疗方面的应用前景。随着研究的深入,通过外泌体建立有效的早期诊断体系和诊疗方案将为肿瘤的治疗提供新的思路和方法。     

膀胱癌细胞来源外泌体的提取与鉴定

目的:提取并鉴定膀胱癌5637细胞来源外泌体。方法:收集膀胱癌5637细胞培养上清液,采用多步骤离心法提取膀胱癌5637细胞外泌体。透射电子显微镜观察外泌体形态及颗粒直径。Bradford法定量外泌体蛋白含量。蛋白质免疫印迹鉴定外泌体标志蛋白。结果:20 m L 5637细胞培养基可收集约50-80μg外泌体。膀胱癌5637细胞来源外泌体呈典型的茶杯样形态,外泌体颗粒直径大约在30-150 nm。膀胱癌5637细胞外泌体提取物中可检测到标志蛋白CD63、TSG101、Hsp70和Hsp90表达。结论:多步骤离心法可以用于提取膀胱癌5637细胞外泌体,为后续开展膀胱癌5637细胞外泌体作用与机制的研究奠定了基础。     

外泌体在肝纤维化中的作用

外泌体(exosomes)是一种能被大多数细胞分泌的微小膜泡,是具有脂质双层膜结构的细胞外囊泡。现认为外泌体是细胞外囊泡(extracellular vesicles, EVs)的一种亚群。研究表明,外泌体是细胞间信息传递的一种载体。肝脏既可以分泌外泌体,同时也是其他组织细胞产生的外泌体的作用靶点,且肝内与肝外来源的外泌体与肝纤维化的形成、发生、发展均有密切联系。本文主要就外泌体在肝纤维化相关疾病中的作用及外泌体与肝纤维化指标之间的关系进行综述。     

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.