NLRP3 炎性小体研究新进展

NLRP3 炎性小体是一种分子量约为700Kda 的大分子多蛋白复合体,能被多种病原相关的分子模式或损伤相关的分子模式 活化,对固有免疫系统免疫功能的发挥具有极其重要的作用。但如果其被过度激活则可通过活化的半胱天冬酶-1 持续地将 pro-IL-1茁和pro-IL-18 剪切为成熟的IL-1茁和IL-18,进而激活下游信号转导通路,产生大量的炎性介质,引起机体发生严重的炎 症反应,最终促进多种炎症性疾病的发生与发展,如Muckle-Wells综合征、2 型糖尿病、非酒精性脂肪肝、动脉粥样硬化、炎症性肠 病和阿尔兹海默病等。因此,对NLRP3 炎性小体进行深入的研究不仅有助于阐释固有免疫系统如何有效地发挥其免疫功能,而 且作为系列炎症反应的核心,NLRP3 炎性小体还可能成为多种炎症性疾病防治的新靶点。我们就NLRP3 炎性小体的结构与功 能,激活与调控,分布与疾病的近期研究作一综述。     

炎性体与器官移植

炎性体是指存在于细胞质内能够激活半胱天冬酶-1（caspase-1）的大分子复合物,活化的caspase-1通过酶切白细胞介素-1β（IL-1β）和白细胞介素-18（IL-18）前体分子而生成具有生物学活性的IL-1β和IL-18.近来研究发现,炎性体分子NLRP1、NLRP2、NLRP5、CARD8、CASP5的基因型与移植的临床结果相关,心脏移植排斥反应时ASC和IL-1β的表达升高,缺血再灌注损伤中NLRP3炎性体激活增加IL-1β分泌,表明炎性体的激活与移植排斥反应和缺血再灌注损伤密切相关,但诱导炎性体活化的配体和参与的炎性体分子有待进一步研究.     

NLRP3炎性小体激活调控机制及其在类风湿性关节炎中的潜在作用

NOD样受体热蛋白结构域相关蛋白3(NOD-like receptor family pyrin domain containing 3,NLRP3)炎性小体是一种多蛋白复合物,在非特异性免疫中发挥重要作用,可以通过K+外流、溶酶体损伤、线粒体功能障碍和活性氧生成等途径被激活,产生具有生物活性的白介素-1β(interleukin-1β,IL-1β)、IL-18和肿瘤坏死因子α(tumor necrosis factor alpha,TNF-α),从而导致细胞死亡,激活适应性免疫。NLRP3基因多态性、表达水平、激活状态都与类风湿性关节炎的疾病进程关系密切,并且NLRP3炎性小体异常激活驱动的慢性炎症在类风湿性关节炎发生发展中发挥重要作用。本文就NLRP3炎性小体的分子结构、基本生物学功能及其与类风湿性关节炎疾病进程之间的相关性作一综述,以期为防治该类自身免疫性疾病提供新思路。     

NLRP3炎症小体在真菌感染中的作用机制研究进展

炎症小体(Inflammasome)是细胞内识别危险信号的多蛋白复合体,是固有免疫的重要组成部分,NOD样受体家族含热蛋白结构域蛋白3炎症小体(NLRP3)是目前研究最多的一种炎症小体。真菌感染中,NLRP3炎症小体通路募集半胱天冬蛋白酶的前体半胱氨酸天冬氨酸蛋白酶1(pro-caspase-1)自身剪切活化,活化后的半胱天冬蛋白酶(Caspase-1),通过对促炎因子IL-1β(interleukin-1β, IL-1β)和IL-18(interleukin-18, IL-18)的激活,引起宿主的炎症反应,在宿主免疫应答中发挥了重要作用。     

NLRP3炎症小体介导的炎症相关疾病研究进展

炎症小体在炎症相关疾病的发生发展中发挥重要作用,其中NLRP3炎症小体能够被多种病原相关分子模式(pathogen-associated molecular patterns,PAMPs)和损伤相关分子模式(damage-associated molecular patterns,DAMPs)激活,进而活化caspase-1,释放成熟形式的IL-1β和IL-18,引起机体的炎症反应,并参与多种疾病的发生发展,包括2型糖尿病、痛风、动脉粥样硬化、神经退行性疾病、肿瘤、炎症性肠病等。因此,研究NLRP3炎症小体的作用机制不仅有助于加深对炎症性疾病发生发展的认识,也为寻找此类疾病的潜在治疗靶点提供了新的思路。就NLRP3炎症小体在炎症相关疾病中的研究进展作一综述。     

NLRP3炎症小体与自身免疫性疾病的相关性研究进展

炎症小体是存在于细胞内由激活自身免疫应答的多种蛋白质组成的复合体,可诱导半胱天冬蛋白酶(caspase)-1自我剪切,caspase-1能够调控白细胞介素(IL)-1β、IL-18的产生,并进而刺激炎症小体的形成和分泌,调控机体的自身免疫应答反应。NLRP3炎症小体属于NOD样受体家族,是一种胞内模式识别受体,主要存在于巨噬细胞和树突状细胞,发挥激活机体免疫炎症的关键作用。病原相关分子模式及损伤相关分子模式与NLRPs结合,启动固有免疫应答,从而导致自身免疫性疾病的发生和发展。本文通过分析归纳近年来炎症小体与自身免疫性疾病的相关性的研究进展,以期为以炎症小体为作用靶点,防治自身免疫性疾病的研究提供指导。     

炎性小体在阿尔茨海默病发病中作用的研究进展

阿尔茨海默病(Alzheimer's disease,AD)是一种神经退行性疾病,严重威胁老年人的身体健康。近年研究发现,脑内炎性小体的活化参与该病的发生、发展过程。炎性小体作为一种大分子蛋白复合物,激活Caspase-1前体蛋白,导致炎性因子如IL-1β、IL-18等的成熟与释放,从而引起炎症反应。目前炎性小体与AD的关系仍需进一步研究,本文就炎性小体与AD的研究现状进行综述。     

NLRP3炎症小体及其相关通路与动脉粥样硬化研究进展

动脉粥样硬化所导致的心血管病是人类致死致残的重要原因。炎症因素作为重要危险因素已得到研究者共识,越来越多的证据表明炎症参与了从早期内皮功能障碍到晚期斑块破裂的AS形成的各个阶段。CANTOS研究作为测试AS炎症假说的第一个大规模临床试验,为寻找IL-1β介导的炎症性AS的潜在治疗靶点提供依据。Nod样受体蛋白3炎症小体作为固有免疫系统的一种识别受体,可引起半胱氨酸天冬氨酸特异性蛋白酶1激活,产生和释放成熟的促炎因子白细胞介素1-β,参与炎症反应发生发展。本文对胆固醇结晶,氧化低密度脂蛋白,血流动力学改变,斑块内细胞代谢方式变化等对NLRP3炎症体激活机制以及NLRP3炎症小体的激活途径和临床治疗方法进行综述,以期通过对NLRP3及其相关通路的研究,为临床动脉粥样硬化治疗提供新思路。     

NLRP3炎症小体与2型糖尿病的研究进展

NLRP3炎症小体作为固有免疫系统的重要组成部分,在2型糖尿病的发病过程中起着重要作用,而白细胞介素1β(IL-1β)是介导其发挥作用的关键因子。核糖体蛋白质合成、嘌呤受体P2X7、活性氧敏感的硫氧还原蛋白相互作用蛋白(TXNIP)与NLRP3炎症小体激活密切相关。肥胖时胰岛素作用的靶组织中NLRP3、IL-1β表达均增高,其介导的炎症反应在胰岛β细胞功能障碍、凋亡以及胰岛素抵抗发生过程中起关键作用。NLRP3炎症小体被多种途径激活,从而上调胰岛和脂肪组织中IL-1β的表达,促进胰岛β细胞凋亡及胰岛素抵抗的发生发展,导致糖尿病的产生。     

结核分枝杆菌感染对NLRP3炎性小体活化的调控作用研究进展

结核病(tuberculosis, TB)是一种主要由结核分枝杆菌(Mycobacterium tuberculosis,Mtb)感染引起的世界范围内影响广泛的细菌性疾病。巨噬细胞通过细胞表面表达的多种受体感知进而吞噬Mtb。Mtb侵染巨噬细胞时,ESX-1等分泌系统会激活以NLRP3为代表的炎性小体,并促进下游IL-18和IL-1β的活化和分泌。同时Mtb也可以通过Zmp1、Ptp A等方式抑制NLRP3炎性小体活化,使Mtb得以在宿主细胞内存活和繁殖。揭示NLRP3炎性小体在Mtb感染中的作用及活化机制,可为结核病的预防和治疗提供参考。     

NLRP3炎症体与炎症性疾病

炎症体是胱天蛋白酶的活化平台,并促进一些前炎症细胞因子如IL-1β、IL-18和IL-33的成熟,启动机体的先天性免疫防御功能。炎症体的激活和失调与人类先天及后天的炎症性疾病都密切相关。通过对NLRP1、NL-RP3、IPAF和AIM2炎症体调节机制的研究,可为家族性周期性自身炎症反应、痛风、II型糖尿病等的治疗提供新的靶点。主要就NLRP3炎症体的组成、分布和调节机制及与NLRP3炎症体相关的炎症性疾病进行了简要介绍。     

Vascular endothelial cells senescence is associated with NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation via reactive oxygen species (ROS)/thioredoxin-interacting protein (TXNIP) pathway

Endothelial dysfunction caused by endothelial cells senescence and chronic inflammation is tightly linked to the development of cardiovascular diseases. NLRP3 (NOD-like receptor family pyrin domain-containing3) inflammasome plays a central role in inflammatory response that is associated with diverse inflammatory diseases. This study explores the effects and possible mechanisms of NLRP3 inflammasome in endothelial cells senescence. Results show an increment of pro-inflammatory cytokine interleukin (IL) −1β secretion and caspase-1 activation during the senescence of endothelial cells induced by bleomycin. Moreover, secreted IL-1β promoted endothelial cells senescence through up-regulation of p53/p21 protein expression. NLRP3 inflammasome was found to mediate IL-1β secretion through the production of ROS (reactive oxygen species) during the senescence of endothelial cells. Furthermore, the association of TXNIP (thioredoxin-interacting protein) with NLRP3 induced by ROS promoted NLRP3 inflammasome activation in senescent endothelial cells. In addition, the expressions of NLRP3 inflammasome related genes, ASC (apoptosis associated speck-like protein containing a CARD), TXNIP, cleaved caspase-1 and IL-1β, were also increased in vitro and in vivo studies. These findings indicate that endothelial senescence could be mediated through ROS and NLRP3 inflammasome signaling pathways, suggesting a potential target for the prevention of endothelial senescence-related cardiovascular diseases.     

Negative regulation of NLRP3 inflammasome signaling

Inflammasomes are multiprotein complexes that serve as a platform for caspase-1 activation and interleukin-1β (IL-1β) maturation as well as pyroptosis. Though a number of inflammasomes have been described, the NLRP3 inflammasome is the most extensively studied. NLRP3 inflammasome is triggered by a variety of stimuli, including infection, tissue damage and metabolic dysregulation, and then activated through an integrated cellular signal. Many regulatory mechanisms have been identifi ed to attenuate NLRP3 inflammasome signaling at multiple steps. Here, we review the developments in the negative regulation of NLRP3 inflammasome that protect host from inflammatory damage.     

Autophagy and NLRP3 inflammasome crosstalk in neuroinflammation in aged bovine brains

NLRP3 inflammasome is a multiprotein complex that can sense several stimuli such as autophagy dysregulation and increased reactive oxygen species production stimulating inflammation by priming the maturation of proinflammatory cytokines interleukin-1β and interleukin-18 in their active form. In the aging brain, these cytokines can mediate the innate immunity response priming microglial activation. Here, we describe the results of immunohistochemical and molecular analysis carried out on bovine brains. Our results support the hypothesis that the age-related impairment in cellular housekeeping mechanisms and the increased oxidative stress can trigger the inflammatory danger sensor NLRP3. Moreover, according to the recent scientific literature, we demonstrate the presence of an age-related proinflammatory environment in aged brains consisting in an upregulation of interleukin-1β, an increased microglial activation and increased NLRP3 expression. Finally, we suggest that bovine may potentially be a pivotal animal model for brain aging studies.     

The NLRP3 inflammasome: activation and regulation

The NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome is a cytoplasmic supramolecular complex that is activated in response to cellular perturbations triggered by infection and sterile injury. Assembly of the NLRP3 inflammasome leads to activation of caspase-1, which induces the maturation and release of interleukin-1β (IL-1β) and IL-18, as well as cleavage of gasdermin D (GSDMD), which promotes a lytic form of cell death. Production of IL-1β via NLRP3 can contribute to the pathogenesis of inflammatory disease, whereas aberrant IL-1β secretion through inherited NLRP3 mutations causes autoinflammatory disorders. In this review, we discuss recent developments in the structure of the NLRP3 inflammasome, and the cellular processes and signaling events controlling its assembly and activation.     

Ambiguities in NLRP3 inflammasome regulation: Is there a role for mitochondria?

Background

The NLRP3 inflammasome is a sensor of specific pathogen, host and environmental danger molecules. Upon activation NLRP3 recruits caspase-1, which cleaves and thereby activates precursor interleukin-1β (IL-1β) and IL-18 to initiate immune responses. Several recent studies have posited that the mitochondria are a central regulator of NLRP3 function.

Scope of review

Mitochondrial reactive oxygen species (mtROS) production, mitochondrial apoptosis, mitochondrial DNA (mtDNA) release, mitophagy, calcium induced mitochondrial damage and mitochondrial co-ordination of NLRP3 localization have all been implicated in regulating NLRP3 activity. In this article we review the literature both for and against these models of NLRP3 inflammasome activation, and highlight other recent contentious issues concerning NLRP3 functioning.

Major conclusions

Although many mechanisms have been proposed for activating NLRP3, no unified model has yet to gain acceptance. Further research is required to clarify how the mitochondria might influence NLRP3 activity.

General significance

While the NLRP3 inflammasome is important for host protection against microbial infection, rare genetic mutations in NLRP3 also cause severe auto-inflammatory diseases. More recent research has implicated NLRP3 activity in pathologies such as atherosclerosis, cancer, type 2 diabetes and Alzheimer's disease. Understanding the mechanisms of NLRP3 inflammasome formation and regulation therefore has the potential to uncover new inflammasome and disease specific therapeutic targets. This article is part of a Special Issue entitled Frontiers of Mitochondrial Research.     

Zinc depletion regulates the processing and secretion of IL-1β

Sterile inflammation contributes to many common and serious human diseases. The pro-inflammatory cytokine interleukin-1β (IL-1β) drives sterile inflammatory responses and is thus a very attractive therapeutic target. Activation of IL-1β in sterile diseases commonly requires an intracellular multi-protein complex called the NLRP3 (NACHT, LRR, and PYD domains-containing protein 3) inflammasome. A number of disease-associated danger molecules are known to activate the NLRP3 inflammasome. We show here that depletion of zinc from macrophages, a paradigm for zinc deficiency, also activates the NLRP3 inflammasome and induces IL-1β secretion. Our data suggest that zinc depletion damages the integrity of lysosomes and that this event is important for NLRP3 activation. These data provide new mechanistic insight to how zinc deficiency contributes to inflammation and further unravel the mechanisms of NLRP3 inflammasome activation.     

炎性小体研究进展

炎性小体是由胞浆内模式识别受体组装的多蛋白复合体,是宿主先天免疫系统的重要组成部分。在细胞应对外界危险信号时,炎性小体能激活半胱天冬酶-1,通过调节白介素-1β和白介素-18等促炎性细胞因子的成熟与释放,参与先天性免疫防御。炎性小体活性异常与人类先天性和获得性炎症性疾病密切相关,炎性小体在免疫应答中具有重要作用。综述了炎性小体的组成、功能、激活方式及其与疾病的相关性。