靶向Toll样受体药物研究进展

Toll样受体(TLRs)家族是主要的模式识别受体,能够识别多种人侵的病原体,启动炎性应答通路而调节或控制固有免疫与适应性免疫.一旦TLRs与其特异配体结合后,可激活信号转导级联,在急性炎症反应、细胞信号转导和细胞凋亡中起重要作用.目前临床上有很多靶向TLRs的药物来治疗炎症、免疫疾病以及肿瘤等,因此,深入研究TLRs信号系统与靶向TLR药物的作用机制,有助于拓宽新药研究思路,从而寻找针对性强而有效的治疗药物.     

TLR信号转导通路及其抗病毒感染机制的研究现状

Toll样受体(Toll like receptor,TLR)是近年来发现的机体识别病原相关分子模式(pathogen associated molecular pat-tern,PAMP)从而激活固有免疫应答的重要受体系统,并可激起适应性免疫应答,其通过介导多种信号转导通路激活固有免疫,与宿主抵抗病毒感染、炎症反应及自身免疫性疾病有直接关系。本文就TLR的分子结构、分布、识别的配体、信号转导通路及抗病毒感染机制等的研究现状作一综述。     

Nod样受体与Toll受体介导炎症的研究进展

固有免疫系统是抵御微生物入侵的第一道防线,它依赖模式识别受体识别外源病原微生物然后将其清除。Toll样受体（TLR）和Nod样受体（NLR）是介导免疫识别的重要受体,其通过识别病原体相关分子模式不仅启动了固有免疫应答,而且激活了适应性免疫应答,是连接固有免疫和适应性免疫的桥梁。中性粒细胞是机体早期炎症反应中最重要的炎症细胞,其粘附、活化及凋亡的整个过程可受TLR的调节,促成炎症反应的无损伤性收敛,使机体维持内环境的稳态。     

C型凝集素受体对固有免疫应答的双向调节作用

C型凝集素受体（CLR）是模式识别受体家族中有别于TLR的新家族,在机体免疫应答中发挥着重要作用。近年来,人们对CLR对固有免疫应答的调节作用进行了较为广泛的研究,越来越多的研究发现CLRs对固有免疫应答具有双向调节作用：不同的CLR在固有免疫应答中既可以发挥正性调节作用,也能够发挥负性调节作用;在针对不同的病原体或在抗原提呈细胞不同的成熟状态等条件下,同-CLR在固有免疫应答中也可以发挥正负调节两方面的作用。深入探讨CLR对固有免疫应答的双向调节作用,对于进一步理解免疫应答的精细调节及疾病发病机制的复杂性等都有重要的理论意义,同时也为许多疾病的预防与治疗提供了一种新的策略。     

TLR参与疟疾免疫应答机制的相关研究进展

TLR是一种模式识别受体,通过识别病原体相关分子模式引起相应的免疫应答反应。近年来,TLR在疟原虫诱导的机体免疫应答过程中的作用逐渐得到重视。文章就TLR与DC、T细胞、B细胞、单核与巨噬细胞和补体系统等在疟疾免疫应答中的相互作用作一综述。     

Toll样受体2和Toll样受体4在免疫应答衣原体感染中的作用

衣原体是重要的人类病原体,其能够导致多种疾病的发生.由衣原体引起的许多人类疾病被认为是免疫病理学介导的.已经证明Toll样受体(TLRs)是多种病原体感染的主要模式识别受体( PRRs),在起始固有免疫应答,建立适应性免疫应答中发挥着重要作用.在TLR家族中,TLR2和TLR4与衣原体感染的相关性研究备受关注,在识别衣原体感染、调节宿主的早期免疫应答、炎症反应和病理形成中执行着关键性的作用.研究TLR2和TLR4在免疫应答衣原体感染中的作用可以更好地理解TLRs介导的分子免疫机制,可能有助于研发免疫治疗的分子靶标,最终有效预防、控制衣原体感染引起的疾病.     

Toll样受体7的研究进展

Toll样受体7(TLR7)是一种广泛存在于机体免疫细胞内体膜上的模式识别受体。TLR7在识别结合病毒的单链RNA或人工合成的小分子嘌呤类化合物后,会招募特异接头蛋白,激活一系列信号级联反应,启动高水平的系统性适应性免疫应答,杀伤感染病毒的细胞,从而彻底清除病毒。临床上已经开始利用TLR7激动剂治疗慢性病毒性感染疾病,TLR7激动剂作为免疫佐剂在机体识别和杀伤肿瘤过程中的作用也在逐渐得到重视。     

TLR接头蛋白研究进展

Toll样受体(TLR)是近年来备受关注的一类病原体识别受体,能选择性地识别侵入机体的病原微生物所携带的病原相关分子模式(PAMPs),继而激活信号级联放大,产生免疫应答.目前研究发现,TLR识别相应配体后,由一类包含TLR结构域的接头蛋白MYD88、MAL、TRIF、TRAM和SARM通过MYD88依赖途径或MYD8...     

Toll样受体与免疫排斥

随着Toll样受体(TLR)的发现,固有免疫应答如何调控适应性免疫应答已成为研究的热点。许多研究结果表明,微生物分子触发的病原体相关分子模式(PAMP)和TLR可以被内源性配体激活,并在哺乳动物体内表达。这些“危险信号”在器官移植后对于缺血再灌注损伤的发生、移植器官功能的影响及存活时间都起着重要的作用。     

人类Toll样受体信号转导途径及其介导的免疫作用

人类Toll样受体（TLR）是近年来发现的一类新的细胞表面信号传导跨膜受体,是人体固有免疫和适应性免疫的桥梁。TLR4组织分布较广泛,激活后通过TLR4-NF-κB信号途径促进细胞因子合成、激活T细胞、调节Th1／Th2免疫反应的平衡,从而调节机体的免疫状态。进一步研究TLR4的信号转导途径及其在疾病发展过程中的表达情况,可以为临床预防和治疗疾病提供新的思路和方法。     

TLR2 and TLR4 expression on the immune cells of tuberculous pleural fluid

Toll-like receptors (TLRs) play an important role in mediating the down stream signaling of immune response in tuberculosis. The predominance of Th1 response in tuberculous pleurisy prompted us to study the expression profiles of TLR2 and TLR4 on different immune cells and on subsets of T cells obtained from the site of infection. Our results showed that TLR2 was up-regulated on the monocytes from pleural fluid indicating a prominent role for this receptor in anti-tuberculous immunity. Notably, TLR2 and TLR4 expression were also enhanced on IFN-gamma secreting CD4(+)T cells. However, their expression was down-regulated on activated and IL-4 secreting CD4(+)T cells from the site of infection indicating that TLR expression is differentially modulated on the different subsets of T cells depending on their activation status and cytokine expression. The down-regulation of both TLRs on the natural regulatory T cells despite their higher number at the site of infection might be a mechanism to maintain their suppressive activity.     

Toll样受体在结核病免疫应答中的作用

结核病(Tuberculosis)主要是由结核分枝杆菌(Mycobacterium tuberculosis,MTB)引起的重大传染性疾病。Toll样受体(Toll-like receptors,TLRs)在宿主的抗结核免疫应答中发挥重要作用。研究表明,TLR1、2、4、6和9与宿主抗MTB感染有关,其中TLR2的作用更为突出。免疫应答的早期阶段,TLR2介导了巨噬细胞的活化,通过产生具有直接杀伤效应的分子或者诱导宿主细胞的凋亡抑制MTB的增殖。然而TLR2介导的信号通路也可通过降低MHC-Ⅱ分子的表达来削弱抗原递呈的能力,促进MTB在宿主内的存活。近几年临床研究发现TLRs多态性位点与结核病易感有关也从侧面证实了TLRs在抗MTB感染中发挥重要作用。     

TLR signaling in B-cell development and activation

Expression of Toll-like receptors (TLRs) in B cells provides a cell-intrinsic mechanism for innate signals regulating adaptive immune responses. In combination with other signaling pathways in B cells, including through the B-cell receptor (BCR), TLR signaling plays multiple roles in B-cell differentiation and activation. The outcome of TLR signaling in B cells is largely context-dependent, which partly explains discrepancies among in vitro and in vivo studies, or studies using different immunogens. We focus on recent findings on how B-cell-intrinsic TLR signaling regulates antibody responses, including germinal center formation and autoantibody production in autoimmune disease models. In addition, TLR signaling also acts on the precursors of B cells, which could influence the immune response of animals by shaping the composition of the immune system. With TLR signaling modulating immune responses at these different levels, much more needs to be understood before we can depict the complete functions of innate signaling in host defense.     

Toll-like receptor regulation of intestinal development and inflammation in the pathogenesis of necrotizing enterocolitis

Toll-like receptors (TLRs) are a structurally related family of molecules that respond to a wide variety of endogenous and exogenous ligands, and which serve as important components of the innate immune system. While TLRs have established roles in host defense, these molecules have also been shown to play important roles in the development of various disease states. A particularly important example of the role of TLRs in disease induction includes necrotizing enterocolitis (NEC), which is the most common gastrointestinal disease in preterm infants, and which is associated with extremely high morbidity and mortality rates. The development of NEC is thought to reflect an abnormal interaction between microorganisms and the immature intestinal epithelium, and emerging evidence has clearly placed the spotlight on an important and exciting role for TLRs, particularly TLR4, in NEC pathogenesis. In premature infants, TLR4 signaling within the small intestinal epithelium regulates apoptosis, proliferation and migration of enterocytes, affects the differentiation of goblet cells, and reduces microcirculatory perfusion, which in combination result in the development of NEC. This review will explore the signaling properties of TLRs on hematopoietic and non-hematopoietic cells, and will examine the role of TLR4 signaling in the development of NEC. In addition, the effects of dampening TLR4 signaling using synthetic and endogenous TLR4 inhibitors and active components from amniotic fluid and human milk on NEC severity will be reviewed. In so doing, we hope to present a balanced approach to the understanding of the role of TLRs in both immunity and disease pathogenesis, and to dissect the precise roles for TLR4 in both the cause and therapeutic intervention of necrotizing enterocolitis.     

More than complementing Tolls: complement–Toll-like receptor synergy and crosstalk in innate immunity and inflammation

Complement and Toll-like receptors (TLRs) play key roles in the host immune response and are swiftly activated by infection or other types of immunological stress. This review focuses on the capacity of complement and TLRs to engage in signaling crosstalk, ostensibly to coordinate immune and inflammatory responses through synergistic or antagonistic (regulatory) interactions. However, overactivation or dysregulation of either system may lead—often synergistically—to exaggerated inflammation and host tissue injury. Intriguingly, moreover, certain pathogens can manipulate complement–TLR crosstalk pathways in ways that undermine host immunity and favor their persistence. In the setting of polymicrobial inflammatory disease, subversion of complement–TLR crosstalk by keystone pathogens can promote dysbiosis. Knowledge of the molecular mechanisms underlying complement–TLR crosstalk pathways can, therefore, be used productively for tailored therapeutic approaches, such as, to enhance host immunity, mitigate destructive inflammation, or counteract microbial subversion of the host response.     

What the Myddosome structure tells us about the initiation of innate immunity

Signaling by the toll-like receptor (TLR) and interleukin-1 receptor superfamily requires the adapter protein myeloid differentiation primary response protein 88 (MyD88). The recent determination of the structure of the so-called Myddosome provides us with new insights into the structural basis for innate immune signaling. Other information on the biochemistry and genetics of MyD88 and other adapters, such as MyDD adapter-like and TRIF-related adapter molecule, allows us to describe in some detail the signaling process activated by TLRs and provides new insights into the role these important proteins play in innate immunity.     

MicroRNA-21 contributes to suppress cytokines production by targeting TLR28 in teleost fish

Toll-like receptors (TLRs) as important pattern recognition receptors, play critical roles in identifying pathogens and activating the immune response. However, when the dysregulation was occurred in this process, it could lead to excessive immune response, so it need many regulatory factors to control this process. Recently, microRNAs (miRNAs) have been shown to act as an important regulator in TLRs signaling pathway. As a member of TLRs family, TLR28 has been newly discovered in teleost fish, and play an important role in the immune response. In this study, we found that the expression of miR-21 was up-regulated after poly(I:C) stimulation, and miR-21 could inhibit the expression of cytokines. Then we predicted the target genes of miR-21, and found that TLR28 is a direct target of miR-21, which could be significantly down-regulated by both miR-21 mimics and pre-miR-21. These results suggested that miR-21 can inhibit the expression of cytokines by negative regulation of TLR28, thereby inhibiting the generation of excessive immunity and maintaining the balance of the body. This study is the first to demonstrate that miRNA can suppresses cytokines by regulating the TLR signaling pathway in teleost fish, and also can provides some new ideas for the research of the regulation of miRNA and immune system in mammals.     

Toll-Like Receptors in Human Papillomavirus Infection

Infection with human papillomaviruses (HPVs) often causes cutaneous benign lesions, cervical cancer, and a number of other tumors. The mechanisms of host immune system to prevent and control HPV infection still remain poorly understood. Toll-like receptors (TLRs) are specific pattern recognition molecules that bind to microbial components to trigger innate immunity and direct adaptive immunity in the face of immunological danger. TLRs have been established to play an essential role in sensing and initiating antiviral immune responses. Recent accumulating evidence demonstrated that HPVs modulate TLR expression and interfere with TLR signaling pathways, leading to persistent viral infection and carcinogenesis. This review summarizes current knowledge on the roles of TLR during HPV infection, focusing on TLR recognition, modulation of TLR expression and signaling, regulatory receptors involved in TLR signaling, and cross-talk of TLRs with antimicrobial peptides. Immunotherapeutic strategies based on TLR agonists have emerged to be one of the novel promising avenues in treatment of HPV-associated diseases in the future.