乙型脑炎病毒NS1蛋白激活NF-κB通路诱导神经元细胞炎性焦亡

乙型脑炎病毒（Japanese encephalitis virus,JEV）是黄病毒科,单股正链RNA病毒,JEV感染主要引起中枢神经系统炎性损伤。细胞焦亡（pyroptosis）是一种依赖于胱天蛋白酶的炎性细胞程序性死亡。非结构蛋白1(NS1)是黄病毒科类病毒与宿主相互作用的重要蛋白,在病毒的复制、致病及免疫逃逸过程中起关键作用。为了阐明NS1蛋白是否影响JEV诱导的神经元细胞炎性焦亡及其作用机制,本研究以神经元细胞SH-SY5Y为研究对象,以转染pcDNA3.1空载质粒为对照组、转染pcDNA3.1-NS1为实验组进行实验。结果表明,与转染pcDNA3.1空载质粒组相比,转染pcDNA3.1-NS1组中JEV的病毒载量、焦亡相关因子NLRP3、Caspase1、IL-1β及IL-18基因的表达量显著上升,并且与转染pcDNA3.1空载质粒组相比,转染pcDNA3.1-NS1处理组中p-P65/P65蛋白的表达量显著上调,p-IκBα/IκBα蛋白的表达量显著下调,表明NS1蛋白能激活细胞中NF-κB信号通路。随后使用NF-κB激动剂LPS及NF-κB抑制剂BAY 11-7082探...     

细胞焦亡:一种与炎症相关的细胞死亡

细胞焦亡是一种促炎症性和溶解性的细胞模式死亡,它是依赖半胱天冬酶-1(caspase-1)的激活所引起的一系列反应,最终作用于细胞,产生一种介于凋亡和坏死之间的细胞死亡。机体通过触发细胞焦亡而起到保护机体免受外界感染的作用,其中炎症小体激活半胱天冬酶-1(caspase-1)对于细胞焦亡的诱导起着重要的作用。本文主要介绍细胞焦亡及其被诱发的分子机制新进展,及与临床贴近的最新进展。     

GSDMD调控非酒精性脂肪肝中细胞焦亡的研究进展

细胞焦亡是一种炎症相关的细胞程序性死亡方式,由胱天蛋白酶(caspase)和炎性小体介导,最终依赖gasdermin家族成员gasdermin D(GSDMD)执行。细胞焦亡的发生伴随着细胞内炎性因子的外泄及免疫细胞的活化,因此与炎症反应的发生密切相关。非酒精性脂肪性肝病(nonalcoholic fatty liver disease, NAFLD)是一种病因不明的慢性肝病,如果缺乏有效的干预手段,脂肪变性会逐渐进展至炎症、纤维化,最终发展至肝硬化。GSDMD 介导的细胞焦亡在非酒精性脂肪性肝病的发病过程中扮演重要角色,不仅会导致肝细胞死亡,还会加重炎症反应和纤维化的进程。抑制GSDMD 的功能从而减少细胞焦亡能够有效地缓解NAFLD 中的脂质堆积和炎症反应,这将为NAFLD 的治疗开辟一个新的研究方向。本文将概述GSDMD 介导的细胞焦亡的分子机制,并关注GSDMD 和细胞焦亡在NAFLD 发病机制及治疗方面的研究进展,为NAFLD 的诊治提供新思路。     

炎性小体在诱导脊髓损伤神经炎症中的作用

脊髓损伤的治疗与康复一直是医学领域的重大难题,尤其是在改善损伤的神经功能方面进展甚微。继发性损伤是造成脊髓损伤后神经功能障碍的主要原因,炎症反应是继发性损伤阶段最重要的病理过程。急性期通过抑制神经炎症来减轻继发性损伤被认为可减轻神经功能损害而达到神经保护作用。炎性小体是一类蛋白质复合体,由模式识别受体中的NLRs家族和PHYIN家族的受体蛋白质作为主要框架组装并命名,常见的炎性小体包括NLRP1、NLRP3、NLRC4(IPAF)、AIM2等。在感染或受到损伤刺激时,炎性小体在细胞质内组装,并激活促炎症蛋白酶胱天蛋白酶1(caspase-1),活化的胱天蛋白酶1一方面促进促炎症细胞因子IL-1β和IL-18的前体成熟和分泌,另一方面介导细胞焦亡。细胞焦亡以细胞肿胀破裂并释放细胞内容物为特征,是在炎症和应激的病理条件下诱导的程序性细胞死亡方式。促炎症细胞因子和焦亡释放的胞内物质都可作为促炎信号引发炎症反应。近期发现,炎性小体通过诱导促炎因子释放以及介导细胞焦亡等途径, 参与激活脊髓损伤后的炎症级联反应,加重继发性神经炎症。靶向抑制炎性小体的激活可减轻炎症反应,促进神经细胞存活,达到神经保护作用。因此,炎性小体有望成为脊髓损伤治疗的新靶点。本文拟从炎性小体的结构及其在脊髓损伤中的作用、激活机制和治疗前景进行综述,以期为后续研究提供思路。     

GSDMD介导的细胞焦亡在感染性疾病中的研究进展

细胞焦亡是细胞感染时由炎症小体介导,以裂解细胞为特点的程序性死亡形式。其激活途径分为依赖半胱氨酸蛋白酶-1或半胱氨酸蛋白酶-4/5/11活化的经典与非经典途径。目前的研究表明细胞焦亡过程中主要效应蛋白是具有膜成孔活性的gasdermin(也作GSDM)家族成员。因此,细胞焦亡也被称为gasdermin介导的程序性坏死。当宿主受到感染时,细胞焦亡与宿主自身其他免疫防御机制存在互相调节机制,保证宿主在清除感染的同时降低自身损伤程度。本文笔者将从研究最为广泛的GSDMD在细胞焦亡途径中的作用机制、细胞焦亡在感染性疾病中的研究进展以及细胞焦亡与其他程序性死亡在感染性疾病中的相互作用这三个方面作系统叙述,期望为今后研究如何通过细胞焦亡途径治疗感染性疾病提供理论基础。     

炎性小体激活与细胞焦亡的研究进展

细胞焦亡是一种依赖天冬氨酸特异性半胱氨酸蛋白酶1(cysteinyl aspartate specific proteinase 1,caspase-1)/caspase-11的程序性细胞死亡方式。炎性小体的激活在细胞焦亡过程中扮演重要角色。当病原体入侵时,核苷酸结合寡聚化结构域样受体(nucleotide-binding oligomerization domain-like receptor,NLR)和黑色素瘤缺乏因子2(absent in melanoma 2,AIM2)等胞内模式识别受体(pattern recognition receptor,PRR)与相应配体结合,导致炎性小体多蛋白复合物组装和caspase-1/caspase-11激活,进而诱导细胞焦亡发生。深入研究炎性小体激活和细胞焦亡的相关机制,对认识炎症性疾病的发生发展非常重要。本文就炎性小体激活与细胞焦亡的研究进展进行综述。     

细胞焦亡机制及与疾病的关系

细胞焦亡(pyroptosis)是近年来发现的一种区别于细胞凋亡的促炎程序性死亡方式。焦亡途径包括半胱天冬酶(caspase)-1介导的经典焦亡途径和Caspase-4/5/11介导的非经典焦亡途径。细胞焦亡涉及多种炎性小体的激活,如核苷酸结合寡聚化结构域样受体蛋白3(NLR pyrin domain containing 3,NLRP3)、核苷酸结合寡聚化结构域样受体蛋白C4 (NLR containing a caspase recruitment domain 4,NLRC4)以及黑色素瘤缺乏因子2 (absent in melanoma 2,AIM2)等。Gasdermin-D(GSDMD)是参与细胞焦亡的关键切割蛋白,最终导致膜蛋白通道开放、膜孔形成、白细胞介素(interleukins,ILs)释放,从而扩大炎症反应。细胞焦亡介导许多疾病如感染性疾病、神经系统疾病、心血管疾病、代谢性疾病以及炎症免疫性疾病等。本文综述了细胞焦亡机制及与疾病关系的研究进展。     

细胞焦亡研究进展

细胞焦亡是一种促炎性的细胞程序性死亡方式,其生化及形态学特征、发生机制都与细胞凋亡等其他细胞死亡方式有着显著的不同。细胞焦亡的发生不仅与感染性疾病有关,而且与代谢性疾病、神经系统疾病和动脉粥样硬化等疾病的发生、发展密切相关。通过对细胞焦亡发生机制及其与相关疾病发生、发展的关系进行研究,有利于了解这些疾病的发病机理,并为治愈这些疾病提供新的思路及作用靶点。     

AIM2炎症小体介导细胞焦亡的研究进展

细胞焦亡是一种程序性细胞死亡，参与了多种疾病的发生发展，而炎症反应在细胞焦亡中的作用是目前的研究热点。炎症小体是炎症反应的重要组成部分，其中黑色素瘤缺乏因子2 (absent in melanoma 2,AIM2)炎症小体的激活是诱发由含半胱氨酸的天冬氨酸蛋白酶1 (caspase-1)介导的细胞焦亡的重要因素。靶向AIM2炎症小体激活与细胞焦亡可作为临床相关疾病治疗的有效策略，本文综述了AIM2炎症小体介导的细胞焦亡的研究进展。     

细胞焦亡的机制和功能

细胞焦亡(pyroptosis)是一种高度促炎性的细胞程序性死亡,最早是在受细菌感染或者细菌毒素处理后的巨噬细胞中观察到的,很长一段时间被误认为是一种巨噬细胞特异的、依赖于能够切割白介素1β的促炎性蛋白酶caspase-1的细胞死亡.后续的研究发现,胞浆内模式识别受体识别病原体来源的模式分子或者机体本身来源的危险信号分子形成炎症小体(inflammasomes),招募和激活caspase-1导致细胞焦亡;鼠的caspase-11和人的caspase-4/5直接作为模式识别受体识别细菌脂多糖类脂A组装的炎症小体也导致细胞焦亡,这一发现颠覆了传统炎症小体的概念.与caspase-1不同, caspase-11/4/5不能切割白介素且引起的细胞焦亡在非单核细胞中也普遍存在.最新的研究发现, caspase-1以及caspase-11/4/5都能切割共同的底物gasdermin D(GSDMD)导致裂解性细胞死亡.GSDMD属于一类具有膜打孔活性的gasdermin家族蛋白成员,细胞焦亡也被重新定义为gasdermin介导的程序性坏死样细胞死亡,开创了细胞焦亡研究的新领域.本文回顾了细胞焦亡研究的历史以及细胞焦亡概念的进化过程,总结了caspase-1和caspase-11/4/5上游目前已知的天然免疫通路,讨论了关于细胞焦亡的研究进展尤其是GSDMD以及其他gasdermin家族细胞焦亡执行蛋白的功能和作用机制,以及细胞焦亡和相关蛋白在对抗感染以及人的自身炎症性疾病过程中的作用.     

细胞焦亡参与肿瘤发生分子机制的研究进展

细胞焦亡是一种依赖gasdermin家族蛋白的成孔活性,由半胱氨酸–天冬氨酸特异性蛋白激酶1、4、5、11等介导的以细胞肿胀、质膜穿孔及炎性小分子的释放为特征的新的裂解性、促炎性程序性细胞死亡。目前发现,细胞焦亡参与了多种疾病的发生与发展过程,特别是对肿瘤及肿瘤微环境的形成具有促进及抑制的双重功能,使焦亡成为抗肿瘤药物研究的最新热点之一。该文主要就细胞焦亡在肿瘤发生中的分子机制进行综述,讨论细胞焦亡对肿瘤治疗的意义,以期为肿瘤的靶向治疗提供参考。     

Pyroptosis,and its Role in Central Nervous System Disease

Pyroptosis is an inflammatory form of cell death executed by transmembrane pore-forming proteins known as gasdermins and can be activated in an inflammasome-dependent or -independent manner. Inflammasome-dependent pyroptosis is triggered in response to pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs) and has emerged as an important player in the pathogenesis of multiple inflammatory diseases, mainly by releasing inflammatory contents. More recently, numerous studies have revealed the intricate mechanisms of pyroptosis and its role in the development of neuroinflammation in central nervous system (CNS) diseases. In this review, we summarize current understandings of the molecular and regulatory mechanisms of pyroptosis. In addition, we discuss how pyroptosis can drive different forms of neurological diseases and new promising therapeutic strategies targeting pyroptosis that can be leveraged to treat neuroinflammation.     

Pyroptosis and host cell death responses during Salmonella infection

Salmonella enterica are facultatively intracellular pathogens causing diseases with markedly visible signs of inflammation. During infection, Salmonella interacts with various host cell types, often resulting in death of those cells. Salmonella induces intestinal epithelial cell death via apoptosis, a cell death programme with a notably non-inflammatory outcome. In contrast, macrophage infection triggers caspase-1-dependent proinflammatory programmed cell death, a recently recognized process termed pyroptosis, which is distinguished from other forms of cellular demise by its unique mechanism, features and inflammatory outcome. Rapid macrophage pyroptosis depends on the Salmonella pathogenicity island-1 type III secretion system (T3SS) and flagella. Salmonella dynamically modulates induction of macrophage pyroptosis, and regulation of T3SS systems permits bacterial replication in specialized intracellular niches within macrophages. However, these infected macrophages later undergo a delayed form of caspase-1-dependent pyroptosis. Caspase-1-deficient mice are more susceptible to a number of bacterial infections, including salmonellosis, and pyroptosis is therefore considered a generalized protective host response to infection. Thus, Salmonella-induced pyroptosis serves as a model to understand a broadly important pathway of proinflammatory programmed host cell death: examining this system affords insight into mechanisms of both beneficial and pathological cell death and strategies employed by pathogens to modulate host responses.     

What role does pyroptosis play in microbial infection?

Pyroptosis, a type of programmed cell death mediated by gasdermin, is characterized by the swelling and rupture of cells, release of cellular contents and a strong inflammatory response, which is critical for controlling microbial infection. Pattern recognition receptors recognize the intracellular and extracellular pathogenic microbial components and stimulate the organism's inflammatory response by activating the pyroptosis signaling pathway and releasing interleukin-1β (IL-1β), IL-18, and other inflammatory factors to promote pathogen clearance and prevent infection. In the process of continuous evolution, pathogens have developed multiple strategies to modulate the occurrence of pyroptosis and thus enhance their ability to induce disease; that is, the competition between host cells and pathogens controls the occurrence of pyroptosis. Competition can directly affect tissue inflammation outbreaks and even alter cell survival. Studies have shown that various bacterial infections, including Shigella flexneri, Salmonella, Listeria monocytogenes, and Legionella pneumophila, can lead to pyroptosis. Pyroptosis is associated with the occurrence and development of various diseases caused by microbial infection, and the identification of molecules related to the pyroptosis signaling pathway may provide new drug targets for the treatment of related diseases. This study reviews the molecular mechanisms of pyroptosis and the role of pyroptosis in microbial infection-related diseases.     

Pyroptosis in Steatohepatitis and Liver Diseases

Pyroptosis is an inflammatory form of regulated cell death, which functions in the clearance of intracellularly replicating pathogens by cell lysis in order to induce further immune response. Since the discovery of the gasdermin (GSDM) family, pyroptosis has attracted attention in a wide range of inflammatory diseases such as nonalcoholic steatohepatitis and other liver diseases. Due to the cleavage of GSDMs by different caspases, the amino-terminal GSDM fragments form membrane pores essential for pyroptosis that facilitate the release of inflammatory cytokines by loss of ionic gradient and membrane rupture. In this review, we address the key molecular and cellular processes that induce pyroptosis in the liver and its significance in the pathogenesis of common liver diseases in different human and experimental mice studies.     

Inflammasome-associated cell death: Pyroptosis,apoptosis, and physiological implications

Inflammasomes are innate immune mechanisms that promote inflammation by activating the protease caspase-1. Active caspase-1 induces pyroptosis, a necrotic form of regulated cell death, which facilitates the release of intracellular proinflammatory molecules, including IL-1 family cytokines. Recent studies identified mediators of inflammasome-associated cell death and suggested that inflammasomes induce not only pyroptosis, but also apoptosis. Caspase-1 has the potential to induce pyroptosis and apoptosis in a manner that is dependent on the expression of the pyroptosis mediator gasdermin D. Caspase-1-induced apoptosis is mediated by Bid and caspase-7. Caspase-8 is also activated following the formation of inflammasomes and may induce apoptosis. Because inflammasomes contribute to the pathogenesis of inflammatory disorders and host defenses against microbial pathogens, a more detailed understanding of the mechanisms underlying inflammasome-associated cell death may contribute to the development of novel therapeutic strategies for inflammasome-related diseases. Pyroptosis has been implicated in inflammasome-related diseases, and compounds that inhibit this process have been reported. The molecular mechanisms of inflammasome-associated cell death and its physiological implications are discussed herein.     

Mafenide derivatives inhibit neuroinflammation in Alzheimer's disease by regulating pyroptosis

The main mechanism of pyroptosis is Caspase-1–mediated GSDMD cleavage, and GSDMD is also the executive protein of pyroptosis. Our previous study has shown that mafenide can inhibit pyroptosis by inhibiting the GSDMD-Asp275 site to suppress cleavage. In this study, sulfonamide was used as the parent nucleus structure to synthesize sulfa-4 and sulfa-20. Screening of drug activity in the pyroptosis model of BV2 and iBMDM cell lines revealed the efficacy of five compounds were superior to mafenide, which exerted a better inhibitory effect on the occurrence of pyroptosis. For in vivo assay, Sulfa-4 and Sulfa-22 were intervened in the neuroinflammation APP/PS1 mice. As a result, the administration of Sulfa-4 and Sulfa-22 could significantly inhibit the activation of microglia, decrease the expression of inflammatory factors in the central nervous system and simultaneously suppress the production of p30-GSDMD as well as the expression of upstream NLRP3 inflammasome and Caspase-1 protein. Immunoprecipitation and Biotin-labelled assay confirmed the targeted binding relationship of Sulfa-4 and Sulfa-22 with GSDMD protein in the iBMDM model in vitro. In this study, we investigated a new type inhibitor of GSDMD cleavage, which exerted a good inhibitory effect on pyroptosis and provided new references for the development of inflammatory drugs in the future.     

Role of pyroptosis in cardiovascular disease

Cardiac function is determined by the dynamic equilibrium of various cell types and the extracellular matrix that composes the heart. Cardiovascular diseases (CVDs), especially atherosclerosis and myocardial infarction, are often accompanied by cell death and acute/chronic inflammatory reactions. Caspase‐dependent pyroptosis is characterized by the activation of pathways leading to the activation of NOD‐like receptors, especially the NLRP3 inflammasome and its downstream effector inflammatory factors interleukin (IL)‐1β and IL‐18. Many studies in the past decade have investigated the role of pyroptosis in CVDs. The findings of these studies have led to the development of therapeutic approaches based on the regulation of pyroptosis, and some of these approaches are in clinical trials. This review summarizes the molecular mechanisms, regulation and cellular effects of pyroptosis briefly and then discusses the current pyroptosis studies in CVD research.     

E3 ubiquitin ligase SYVN1 is a key positive regulator for GSDMD-mediated pyroptosis

Gasdermin D (GSDMD) participates in the activation of inflammasomes and pyroptosis. Meanwhile, ubiquitination strictly regulates inflammatory responses. However, how ubiquitination regulates Gasdermin D activity is not well understood. In this study, we show that pyroptosis triggered by Gasdermin D is regulated through ubiquitination. Specifically, SYVN1, an E3 ubiquitin ligase of gasdermin D, promotes GSDMD-mediated pyroptosis. SYVN1 deficiency inhibits pyroptosis and subsequent LDH release and PI uptake. SYVN1 directly interacts with GSDMD, and mediates K27-linked polyubiquitination of GSDMD on K203 and K204 residues, promoting GSDMD-induced pyroptotic cell death. Thus, our findings revealed the essential role of SYVN1 in GSDMD-mediated pyroptosis. Overall, GSDMD ubiquitination is a potential therapeutic module for inflammatory diseases.Subject terms: Cell death and immune response, Immune cell death     

African swine fever virus cysteine protease pS273R inhibits pyroptosis by noncanonically cleaving gasdermin D

African swine fever (ASF) is a viral hemorrhagic disease that affects domestic pigs and wild boar and is caused by the African swine fever virus (ASFV). The ASFV virion contains a long double-stranded DNA genome, which encodes more than 150 proteins. However, the immune escape mechanism and pathogenesis of ASFV remain poorly understood. Here, we report that the pyroptosis execution protein gasdermin D (GSDMD) is a new binding partner of ASFV-encoded protein S273R (pS273R), which belongs to the SUMO-1 cysteine protease family. Further experiments demonstrated that ASFV pS273R-cleaved swine GSDMD in a manner dependent on its protease activity. ASFV pS273R specifically cleaved GSDMD at G107-A108 to produce a shorter N-terminal fragment of GSDMD consisting of residues 1 to 107 (GSDMD-N_1–107). Interestingly, unlike the effect of GSDMD-N_1–279 fragment produced by caspase-1-mediated cleavage, the assay of LDH release, cell viability, and virus replication showed that GSDMD-N_1–107 did not trigger pyroptosis or inhibit ASFV replication. Our findings reveal a previously unrecognized mechanism involved in the inhibition of ASFV infection-induced pyroptosis, which highlights an important function of pS273R in inflammatory responses and ASFV replication.