程序性细胞坏死的分子机制及其在炎症中的作用

越来越多的研究表明,细胞坏死是一种受到精密调控的"新型"程序性细胞死亡方式。当细胞凋亡不能正常发生而细胞必须死亡时,坏死作为凋亡的"替补"方式被激活。程序性细胞坏死主要由肿瘤坏死因子受体(tumor necrosis factor receptor,TNFR)家族以及Toll样受体(Toll-like receptor,TLR)家族启动,并通过和受体蛋白互作的两个蛋白激酶RIP1(receptor interacting protein kinase 1)和RIP3(receptor interacting protein kinase 3)传递死亡信号,募集并磷酸化MLKL(mixed lineage kinase domain-like protein),而MLKL作为细胞死亡的执行者最终会导致坏死的发生。坏死的细胞会向周围释放其内容物,这些内容物作为DAMPs(damage-associated molecular pattern molecules)可刺激周围细胞发生炎症反应,激活机体免疫应答。该文以TNF-α诱导的细胞坏死途径为出发点,着重阐述程序性细胞坏死的分子机制及其在炎症中的作用,并回顾和展望了其在临床诊疗中的可能性。     

细胞程序性坏死——一种细胞死亡新方式

细胞死亡是生命的基本过程之一。细胞程序性坏死(necroptosis,Nec)是近年发现的一种新型细胞死亡的方式,研究活跃。Nec有着与通常的细胞坏死类似的形态学特征,但受到特别的死亡信号通路调控。受体相互作用蛋白(receptor interacting protein,RIP)1和3是Nec信号通路中极为重要的调节蛋白。RIP1是决定细胞生存和死亡的交叉点;RIP3则是决定细胞死亡方式(凋亡或Nec)的转换器。本文介绍Nec的信号机制,并简略地探讨其在器官缺血坏死、炎症反应和肿瘤发病机理中的意义。     

程序性细胞坏死在疾病中的研究进展

细胞坏死自从被发现具有严格的"程序性调控"特征以来,其信号转导机制以及相关疾病机理引起了学术界广泛关注并展开大量研究。程序性细胞坏死(necroptosis)是一种不同于凋亡及传统坏死的新的细胞死亡方式,主要由肿瘤坏死因子受体(tumor necrosis factor receptor, TNFR)家族或Toll样受体(Toll-like receptor, TLR)家族调控启动。死亡受体被激活之后,与受体蛋白相互作用的两个蛋白激酶RIP1(receptor interacting protein kinase 1)和RIP3被激活,进而招募RIP3的底物MLKL(mixed lineage kinase domain-like protein)并催化它发生磷酸化,磷酸化的MLKL发生寡聚化转位到质膜上,引起膜通透性的改变,最终实现坏死的发生。细胞坏死是一种促炎性的程序性细胞死亡方式,其过程中伴有大量细胞内容物的释放。如损伤相关的模式分子(damage associated molecular patterns, DAMP)的释放,会激活机体的免疫应答,因此其广泛参与到各种疾病的病理生理过程中,包括神经退行性疾病、感染性炎症性疾病、缺血再灌注损伤、肿瘤发生及转移等。细胞坏死抑制剂有望被应用于对这些疾病的干预来改善患者病情及预后。该文将详细阐述程序性细胞坏死在胚胎发育、组织稳态、炎症相关疾病、肿瘤、神经系统相关疾病等疾病中的作用,并对其在临床治疗中的应用进行回顾及展望。     

Caspase-1在炎症及程序性细胞死亡过程中的作用

Caspase家族是一类半胱氨酸天冬氨酸特异性蛋白酶,其中caspase-1是最先在哺乳动物细胞中被鉴定出来的家族成员,介导了某些特定类型细胞的凋亡。在微生物感染或细胞内危险信号存在时,caspase-1可通过与炎性体结合而发生激活,从而加工pro-IL-1β和pro-IL-18等炎症因子使其成熟并释放,在炎症反应中起着核心调控作用。此外,caspase-1还能介导一种特殊的促炎症的程序性细胞死亡(Pyroptosis)。caspase-1参与的炎症及程序性细胞死亡能有效提高机体抵抗内源和外源各种刺激的能力,达到保护宿主的目的,而caspase-1的功能异常则与多种疾病密切相关。     

RIP3介导程序性坏死与炎症研究进展CSCD

受体相互作用蛋白激酶3(receptor-interacting protein kinase 3,RIP3/RIPK3)是RIP家族中的一员,具有丝氨酸/苏氨酸蛋白激酶活性,通过与RIP1形成坏死复合体能够介导caspase非依赖的细胞坏死。研究发现,RIP3也参与众多感染和无菌性炎性疾病的病理进程。本文就RIP3在细胞程序性坏死方面的调控机制和其在坏死依赖性与非依赖性炎症方面作一综述。     

Necroptosis信号通路与靶向治疗的研究进展

Necroptosis是一种可调控的细胞程序性坏死途径,它具有与不可调控性细胞坏死相同的形态学特征。Necroptosis是caspase非依赖的。当细胞凋亡被阻断时,necroptosis信号通路由死亡结构域激活启动,其中RIP1的活化是necroptosis的关键步骤,该步骤可被necrostatin-1特异性抑制。近期研究表明,necroptosis在缺血性损伤、神经退行性疾病、恶性肿瘤、病毒感染和免疫性疾病等多种疾病的病理生理过程中起重要作用,有望作为药物开发的新靶点。对necroptosis的发现历程、信号通路及其在疾病病理生理机制中的作用和靶向necroptosis的治疗等四个方面进行综述。     

RIP3介导程序性坏死与炎症研究进展

受体相互作用蛋白激酶3(receptor-interacting protein kinase 3,RIP3/RIPK3)是RIP家族中的一员,具有丝氨酸/苏氨酸蛋白激酶活性,通过与RIP1形成坏死复合体能够介导caspase非依赖的细胞坏死。研究发现,RIP3也参与众多感染和无菌性炎性疾病的病理进程。本文就RIP3在细胞程序性坏死方面的调控机制和其在坏死依赖性与非依赖性炎症方面作一综述。     

NF-κB家族成员RelA的翻译后修饰及其生理病理作用的研究进展

真核细胞转录因子NF-κB通过调节多种靶基因表达,参与炎症、免疫反应、程序性细胞死亡、细胞增殖和分化的调控。RelA是NF-κB家族一个重要的成员,其翻译后修饰可精准调控NF-κB的转录活性,在调节炎症、肿瘤、代谢以及免疫应答等重要的生命活动及相关疾病的发生发展过程中起重要作用。现总结相关领域最新研究进展,综述RelA翻译后修饰的种类、调控机制,对NF-κB通路功能的影响,及其在NF-κB介导的炎症、癌症等多种疾病中的功能。     

程序性坏死与心脑血管疾病

程序性坏死(necroptosis)是一种新型的细胞程序性死亡类型,受细胞内信号因子的调控,但同细胞凋亡有着显著区别。程序性坏死的发生需要一系列分子传递和执行死亡信号,受体相互作用蛋白激酶RIP1和RIP3是关键的调控因子。这种细胞死亡模式在心脑血管疾病的病理过程中起着非常重要的作用。     

我国科学家在程序性细胞死亡机制研究领域取得重大突破

程序性细胞死亡在调控植物发育和胁迫响应中具有重要作用, 而活性氧是导致程序性细胞死亡的关键因子。日前, 中科院遗传与发育所李家洋研究组对活性氧调控程序性细胞死亡的分子机制进行了深度解析, 首次阐明了苹果酸作为信号分子, 经由叶绿体-线粒体穿梭途径而引发活性氧产生, 继而导致细胞死亡。该研究成果是程序性细胞死亡调控机制领域的重大突破。     

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.     

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.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.