脂质活性信号分子鞘氨醇-1-磷酸及其生物学特性

鞘氨醇-1-磷酸(sphingosine-1-phosphate,S1P)是目前颇受关注的脂质信号分子.体内S1P主要由红细胞内鞘氨醇激酶催化鞘氨醇合成,后经由ATP结合盒式转运子释放入血浆.血浆S1P超过半数存在于高密度脂蛋白和血清白蛋白上.S1P可通过直接胞内作用和激活其特异性G蛋白偶联受体产生多种重要生物学效应.S1P1-5型受体在体内各类型组织和细胞表达水平不同,参与包括细胞增殖、存活、迁移等多种生物学过程.     

鞘氨醇-1-磷酸与免疫细胞的调节

鞘氨醇-1-磷酸（sphingosine-1 phosphate,S1P）是来源于鞘脂代谢途径的多效性信号分子,其代谢受到多种因素调控。S1P由细胞内的鞘氨醇激酶（sphingosine kinases,SphKs）催化鞘氨醇的磷酸化而合成,可通过转运蛋白释放至细胞外。S1P可通过在胞外结合其特异性G蛋白偶联受体及胞内作用而调节多种重要生物学效应。作为细胞外介质和细胞内信使,S1P在免疫系统中也发挥重要的调节作用。S1P参与免疫细胞的迁移、增殖、分化及死亡细胞清除等过程。本文对S1P的代谢以及其对于免疫细胞的调节作用进行综述。     

1-磷酸鞘氨醇受体

1-磷酸鞘氨醇(sphingosine-1-phosphate,S1P)对动脉粥样硬化等心血管疾病的发生发展具有重要作用。最近研究发现S1P在不同细胞发挥的生物学效应由其受体(sphingosine-1-phosphate receptor,S1PR)介导,以S1PR及其信号机制为基础的研究及治疗策略成为新的研究热点。本文主要综述S1PR的功能、信号通路及对心血管疾病的影响,为心血管疾病的预防和诊疗提供新的靶点。     

鞘氨醇激酶信号途径对骨重建的调节作用

鞘磷脂是哺乳动物细胞质膜的主要成分之一,在其代谢过程中,鞘氨醇激酶（sphingosine kinase, SPHK）是一个关键性的调节酶.鞘磷脂代谢产物鞘鞍醇经SPHK磷酸化作用产生的鞘氨醇-1-磷酸（S1P）是一种具有生物活性的脂类,参与调节骨骼、神经、免疫、血液系统等多种组织细胞的生物学过程.本文阐述了SPHK/S1P信号途径相关分子,并综述了SPHK/S1P通过调节骨组织细胞的形态结构、增殖、迁移、分化形成及凋亡等功能,进而调节骨重建平衡过程的生物学效应及其机制.     

1-磷酸鞘氨醇与相关疾病的研究进展

1-磷酸鞘氨醇(sphingosine-1-phosphate,S1P)是一种重要的生物活性鞘脂类代谢物,其介导的细胞传导途径(SphK-S1P-S1PRs信号通路)参与各种生理病理过程,调节人体生长发育。现发现5种S1P受体(S1PR1-S1PR5)广泛分布于人体各个组织,其形成的交联信号通路影响着细胞的迁移、粘附、存活和增殖,并干预着肿瘤、糖尿病、心血管疾病等诸多疾病的发生发展过程。因而S1PRs的研究对治疗疾病提供了新的靶点和方向,将其应用于临床,实施个体化治疗方案,成为当今热门的研究课题之一。     

鞘磷脂代谢与脑缺血

鞘磷脂特别是鞘脂是髓鞘的主要成分,高度集中在中枢神经系统。在生理和病理生理条件下,具有生物活性的鞘磷脂及其代谢产物以及信号传导过程的重要性正在逐步被人们所认识。鞘脂代谢产物鞘氨醇及其前体物质神经酰胺与细胞生长停滞和凋亡有关,而1-磷酸鞘氨醇与增强细胞增殖、分化和细胞生存以及调节细胞的生理和病理过程有关,具有细胞外第一信使和细胞内第二信使的双重功能。这三者之间的相互转换、鞘脂代谢物的相对水平以及细胞的命运,受到鞘氨醇激酶的活性的强烈影响。鞘氨醇激酶可催化磷酸鞘氨醇产生1-磷酸鞘氨醇。1-磷酸鞘氨醇在中枢神经系统中与G蛋白偶联受体家族结合对中枢神经系统发挥作用。本文对鞘磷脂代谢过程中的鞘氨醇激酶、1-磷酸鞘氨醇及其受体与脑缺血之间的关系进行概述。     

鞘氨醇激酶-磷酸鞘氨醇轴在血管生成相关性疾病中的作用

血管生成是指在原有血管的基础上形成新血管的过程。病理性血管生成是癌症、心血管类疾病和视网膜病变等一系列疾病的标志。1-磷酸鞘氨醇(sphingosine-1-phosphate,S1P)是一种信号脂质,由鞘氨醇激酶（sphingosine kinases,SPHK）合成,通过5种G蛋白偶联受体(sphingosine-1-phosphate receptors,S1PR1-5)发挥其不同的生物学和病理生理作用,并通过激活受体启动各种信号级联反应,影响细胞命运、血管张力、内皮功能和完整性以及淋巴细胞的运输等。其产生和信号的失衡与内皮功能障碍和异常血管生成等病理过程密切相关。越来越多的证据表明, SPHK-S1P轴在血管生成中发挥重要作用,尤其在癌症的发生发展与肿瘤微环境、动脉粥样硬化、心肌梗死等心血管类疾病,以及糖尿病和视网膜病变中具有重要意义。研究其相关作用与功能,可为治疗血管生成相关疾病提供新见解和药物治疗靶点。本文就SPHK-S1P轴通过SPHK以及S1PR1-5影响内皮细胞和平滑肌增殖、内皮细胞迁移以及由内皮细胞、周细胞和平滑肌细胞等形成管腔的分子机制进行阐述,同时进一步阐述SPHK-S1P轴如何通过鞘氨醇激酶以及S1PR1-5影响肿瘤、心血管类疾病、糖尿病以及视网膜病变中血管生成,旨在通过理解SPHK-S1P轴在血管生成中的分子机制为相关疾病提供新的治疗思路。     

S1PR1在心血管系统中的作用及研究进展

1-磷酸鞘氨醇受体1(sphingosine 1-phosphate receptor 1,S1PR1)是5个S1P受体之一,最早发现于内皮细胞分化和新生血管形成过程中。S1PR1广泛表达于内皮细胞、免疫细胞、淋巴细胞、巨噬细胞及肌肉等多种组织细胞。随着研究的不断深入,已经证实S1PR1参与多种机体病理生理过程,可阻止细胞凋亡,促进细胞生长和繁殖,能调节机体免疫和炎症反应并应用于临床。在心血管系统中,S1PR1在血管新生、淋巴细胞运输、心脏的生长发育以及维持血管的正常通透性等方面具有重要作用。本文将着重就S1PR1在心血管系统中作用及其机制的研究进展作一介绍。     

S1P 信号通路：心血管疾病治疗的新靶点

1- 磷酸鞘氨醇是一种有生物活性的脂质代谢产物,具有调节细胞增殖、再生、迁移,细胞内钙离子移动,黏附分子表达以及激活单核细胞黏附内皮细胞等功效,在血管生理性再生及动脉粥样硬化斑块发生发展中发挥重要作用。1- 磷酸鞘氨醇在高密度脂蛋白中含量在所有脂蛋白中最高,其参与调节高密度脂蛋白的抗氧化、抗血栓、抗炎等效应,而这些反应与1- 磷酸鞘氨醇的生物学功能如血管发生、内皮保护、抑制平滑肌细胞迁移、心肌缺血再灌注损伤的保护等密切相关。对1- 磷酸鞘氨醇信号通路在心血管系统中的作用及以该通路为靶点的相关药物研究进展进行综述,为今后研究提供参考。     

植物体内的鞘氨醇-1-磷酸(S1P)

鞘氨醇-1-磷酸（S1P）在植物体内也可作为一种信号分子参与ABA介导的保卫细胞信号转导过程,这一途径和异三聚体G蛋白相耦联。文章对此问题的研究进展作了介绍。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.