巨噬细胞极化与细胞代谢的相互调控

巨噬细胞极化对于机体抵抗病原微生物感染及组织修复等过程中发挥着重要作用。γ干扰素(IFN-γ)和脂多糖(LPS)活化的巨噬细胞称之为经典活化的巨噬细胞(M1),而白细胞介素4(IL-4)和IL-13诱导巨噬细胞的替代激活(M2)。巨噬细胞的极化受到细胞代谢调控,M1型巨噬细胞主要为糖酵解、戊糖磷酸代谢途径供能,而M2型巨噬细胞主要为氧化磷酸化途径参与。本文在总结了巨噬细胞极化对细胞代谢影响的基础上,重点探讨了糖、脂、氨基酸、铁离子、氧化还原反应等代谢通路对其巨噬细胞表型和功能的调节作用。     

长链非编码RNA肺腺癌转移相关转录本1对巨噬细胞极化影响的研究

目的研究长链非编码RNA(lnc RNA)肺腺癌转移相关转录本1(MALAT1)对巨噬细胞极化的影响。方法采用佛波酯诱导人THP-1细胞分化为成熟的巨噬细胞,IFN-γ/LPS刺激诱导M1型极化,IL-4刺激诱导M2型极化,采用实时荧光定量PCR(RT-q PCR)检测各组细胞中MALAT1的表达。si RNA干扰巨噬细胞MALAT1表达,加入IL-4继续诱导M2型极化,RT-q PCR检测极化相关基因表达;酶联免疫吸附试验(ELISA)检测TNF-α、IL-12、CCL22、IL-10的水平。si RNA干扰M2型巨噬细胞MALAT1表达,研究其对M2极化表型的影响。结果 MALAT1在M2型巨噬细胞中表达显著升高,M1向M2极化改变MALAT1表达升高,而M2向M1极化改变MALAT1表达降低。MALAT1干扰后,IL-4诱导的M2型巨噬细胞TNF-α、IL-12分泌升高,CCL22、IL-10分泌降低;CXCL10、CXCL11、HLA-DR表达升高,CCL17、CCL18、CD163表达降低。M2型巨噬细胞MALAT1干扰后,TNF-α、IL-12分泌升高,CCL22、IL-10分泌降低。结论 MALAT1参与调控巨噬细胞极化,干扰MALAT1表达有效抑制M2型巨噬细胞极化,促进M1型巨噬细胞极化。     

YAP调控LPS诱导的巨噬细胞M1型极化

目的 探讨YAP对脂多糖(Lipopolysaccharide, LPS)诱导的巨噬细胞M1型极化的影响。方法 LPS诱导THP-1和U937细胞来源的M0型巨噬细胞向M1型极化。RT-qPCR法检测M1型巨噬细胞的标志物,罗丹明-鬼笔环肽检测细胞骨架,Western blot、RT-qPCR检测Hippo通路相关蛋白及其靶基因的表达。降低M0型巨噬细胞内YAP的表达,RT-qPCR检测LPS再诱导的M1型巨噬细胞的标志物的表达变化。结果 在M0型巨噬细胞向M1型极化过中,Hippo通路关键因子YAP的蛋白水平升高,下游靶基因的表达也升高;敲低YAP或使用维替泊芬抑制YAP表达后,LPS再诱导的M1型巨噬细胞标志物的表达明显降低。结论 YAP可以调控LPS诱导的巨噬细胞向M1极化。     

巨噬细胞极化及其在感染性疾病中的作用

巨噬细胞作为重要的固有免疫细胞和抗原提呈细胞,在机体抗感染免疫中发挥着重要作用.在不同的微环境下,巨噬细胞可发生表型和功能极化从而呈现出不同的功能,一般将经典途径和替代途径活化的巨噬细胞(M1型和M2型)作为巨噬细胞功能可塑性调变的两个极端.随着研究的深入,巨噬细胞极化类型的诱导及特点也逐渐被揭示,其在微生物感染免疫中的作用日益受到重视.     

炙甘草多糖对小鼠巨噬细胞再极化的影响

目的:建立探讨炙甘草中等分子量多糖(MPRR)诱导巨噬细胞极化的情况,阐明肿瘤微环境中极化后巨噬细胞对小鼠4T1乳腺癌细胞生长的影响。方法:培养小鼠RAW264.7巨噬细胞,采用IL-4诱导并建立M2型极化模型,将培养细胞分为未诱导细胞(M0)组、M2极化(IL-4诱导)组、MPRR诱导组和Rp组(IL-4诱导12 h后MPRR再极化诱导组),流式细胞术分析巨噬细胞极化标志(CD86和CD206)的表达。免疫印迹技术分析转录因子STAT-6表达和磷酸化。收集不同条件下巨噬细胞培养上清液,ELISA法检测其IFN-γ和TGF-β浓度。结果:与对照组比较,IL-4诱导后细胞发生M2极化,可检测到RAW264.7细胞表面CD86表达下降(P0.05),CD206表达增加(P0.05)。而MPRR促进细胞向M1极化,可观察到其促进CD86表达而降低CD206表达(P0.05)。M2极化后STAT-6磷酸化增加,IFN-γ分泌减少而TGF-β分泌增加(P0.05);经MPRR处理减弱STAT-6磷酸化和TGF-β的分泌,促进IFN-γ分泌(P0.05)。结论:炙甘草水溶性多糖促进巨噬细胞的M1极化,可拮抗IL-4诱导其M2极化效应,炙甘草多糖可调节小鼠巨噬细胞再极化。     

肿瘤相关巨噬细胞研究进展

单核巨噬细胞是一种多功能细胞,对不同的微环境信号应答表现出不同的功能.而极化的M1和M2巨噬细胞是巨噬细胞功能表现的两个极端.其中侵润到肿瘤组织的巨噬细胞受肿瘤诱导产生的细胞因子的影响使巨噬细胞表现出巨噬细胞M2型表型,这些极化的巨噬细胞在破坏适应性免疫反应和促进肿瘤生长与进展方面具有重要作用.肿瘤相关巨噬细胞(TAM)可以促进肿瘤进展包括促进肿瘤生长、侵润、转移,促进血管生长和免疫抑制等,因而研究TAM具有重要意义.     

肿瘤相关巨噬细胞研究进展

单核巨噬细胞是一种多功能细胞,对不同的微环境信号应答表现出不同的功能.而极化的M1和M2巨噬细胞是巨噬细胞功能表现的两个极端.其中侵润到肿瘤组织的巨噬细胞受肿瘤诱导产生的细胞因子的影响使巨噬细胞表现出巨噬细胞M2型表型,这些极化的巨噬细胞在破坏适应性免疫反应和促进肿瘤生长与进展方面具有重要作用.肿瘤相关巨噬细胞(TAM)可以促进肿瘤进展包括促进肿瘤生长、侵润、转移,促进血管生长和免疫抑制等,因而研究TAM具有重要意义.     

调控巨噬细胞极化影响创面愈合的因素及机制分析北大核心CSCD

巨噬细胞在创面愈合过程中可极化为经典途径激活的M1型(促炎)与交替途径激活的M2型(抗炎),通过多方面能力影响创面愈合。本文综述了调控创面巨噬细胞极化的多种理化机械因素:高血糖水平阻止创面巨噬细胞向M2型极化;组织滞留状态的铁促进创面巨噬细胞向M1型极化;循环状态的铁促进创面巨噬细胞向M2型极化;感染因素促进创面巨噬细胞向M1型极化;生理性电场促进创面巨噬细胞向M2型极化;基质硬度增强促进巨噬细胞向M1型极化等,并分析各因素影响创面愈合的机制,为创面修复提供更多思路。     

青藤碱对LPS、IL-4诱导的小鼠RAW264.7巨噬细胞极化的影响

目的:探讨青藤碱(Sinomenine,SIN)对脂多糖(LPS)以及白细胞介素4(IL-4)诱导的RAW264.7细胞向M1、M2型极化的影响。方法:以LPS刺激RAW264.7细胞诱导M1型极化,IL-4刺激RAW264.7细胞诱导M2型极化;青藤碱作用于LPS或IL-4诱导的巨噬细胞后:用酶联免疫法(ELISA)检测不同诱导状态下RAW264.7细胞TNF-α和IL-10的分泌量;荧光定量PCR检测与巨噬细胞极化相关的精氨酸酶-1(Arg-1)、一氧化氮合酶(i NOS)、细胞因子信号转导抑制蛋白-2(SOCS2)和细胞因子信号转导抑制蛋白-3(SOCS3)的mRNA表达水平。结果:青藤碱能抑制LPS诱导下细胞TNF-α的分泌量,抑制细胞i NOS和SOCS3的mRNA表达水平的升高。青藤碱能抑制IL-4诱导下细胞IL-10的分泌量和Arg1的mRNA表达水平的升高,对IL-4诱导下细胞SOCS2的mRNA表达水平的升高没有明显影响。结论:青藤碱对LPS诱导下巨噬细胞向M1型极化具有抑制作用;对IL-4诱导下巨噬细胞向M2型极化具有抑制作用。青藤碱对M1/M2亚型的失衡具有调节作用,有利于维持其动态平衡。     

肿瘤相关巨噬细胞研究进展

单核巨噬细胞是一种多功能细胞,对不同的微环境信号应答表现出不同的功能。而极化的MI和M2巨噬细胞是巨噬细胞功能表现的两个极端。其中侵润到肿瘤组织的巨噬细胞受肿瘤诱导产生的细胞因子的影响使巨噬细胞表现出巨噬细胞M2型表型,这些极化的巨噬细胞在破坏适应性免疫反应和促进肿瘤生长与进展方面具有重要作用。肿瘤相关巨噬细胞（TAM）可以促进肿瘤进展包括促进肿瘤生长、侵润、转移,促进血管生长和免疫抑制等,因而研究TAM具有重要意义。     

Intracellular Antibody Immunity

Antibodies allow the immune system to target pathogens despite their tremendous diversity and rapid evolution. Once bound to a pathogen, antibodies induce a broad range of effector mechanisms, including phagocytosis and complement. However, these mechanisms are all initiated in the extracellular space, meaning that pathogens like viruses evade them upon infection of their target cells. Recently, it has been shown that, in addition to mediating extracellular immune responses, antibodies also activate immunity inside infected cells. Antibodies that are bound to the surface of non-enveloped viruses or bacteria are carried into the cell during pathogen entry. Once inside the cell, these pathogen-attached antibodies are recognised by a highly conserved, high affinity cytosolic antibody receptor called TRIM21. TRIM21 initiates both sensor and effector responses that reduce viral replication and induce an antiviral state. These responses are an important part of antiviral immunity and the removal of TRIM21 results in uncontrolled viraemia and death in a mouse model of infection.     

Inflammation and the coagulation system in tuberculosis: Tissue Factor leads the dance

Mycobacterium tuberculosis, the causative agent of tuberculosis, drives the formation of granulomas, structures in which both immune cells and the bacterial pathogen cohabit. The most abundant cells in granulomas are macrophages, which contribute as both cells with bactericidal activity and as targets for M. tuberculosis infection and proliferation during the entire course of infection. The mechanisms and factors involved in the regulation and control of macrophage microenvironment‐specific polarization and plasticity are not well understood, as some granulomas are able to control bacteria growth and others fail to do so, permitting bacterial spread. In this issue of the European Journal of Immunology, Venkatasubramanian et al. [Eur. J. Immunol. 2016. 46: 464–479] show that mice lacking the tissue factor gene in myeloid cells have augmented M. tuberculosis growth and increased inflammation in the lungs. This suggests that tissue factor, an initiator of coagulation, is important for the generation of fibrin, which supports granuloma formation. This article demonstrates for the first time the involvement of tissue factor in inducing effective immunity against M. tuberculosis, and sheds new lights on the complex interplay between host inflammatory response, the coagulation system, and the control of M. tuberculosis infection.     

The impact of mucosal infections on acquisition and progression of tuberculosis

More than one-third of the world's population, or over 2 billion people, are infected with Mycobacterium tuberculosis, the causative pathogen of tuberculosis in humans. Why only 10% of those infected develop active disease while the remainder harbor latent infection remains one of the greatest scientific and public health mysteries. Bacterial persistence is characterized by a dynamic state of immunological tolerance between pathogen and host. The critical role of CD4(+) T cells in defense against intracellular pathogens became evident during epidemiological studies of HIV-1 infection, which showed a clear inverse relationship between CD4(+) T-cell count in peripheral blood and increased risk of infection with M. tuberculosis, pneumocystis and Toxoplasma gondii. There is also growing evidence of a common mucosal immune system, whereby immune cells activated at one mucosal site may disseminate to remote effector sites. In this commentary, we review emerging evidence from human studies that the outcome of M. tuberculosis infection is influenced by concurrent mucosal infections, using Helicobacter pylori and geohelminths as examples. Understanding how the complexity of microbial exposures influences host immunity may have important implications for vaccine development and therapeutic interventions.     

The role of B cells and humoral immunity in Mycobacterium tuberculosis infection

Mycobacterium tuberculosis remains a major public health burden. It is generally thought that while B cell- and antibody-mediated immunity plays an important role in host defense against extracellular pathogens, the primary control of intracellular microbes derives from cellular immune mechanisms. Studies on the immune regulatory mechanisms during infection with M. tuberculosis, a facultative intracellular organism, has established the importance of cell-mediated immunity in host defense during tuberculous infection. Emerging evidence suggest a role for B cell and humoral immunity in the control of intracellular pathogens, including obligatory species, through interactions with the cell-mediated immune compartment. Recent studies have shown that B cells and antibodies can significantly impact on the development of immune responses to the tubercle bacillus. In this review, we present experimental evidence supporting the notion that the importance of humoral and cellular immunity in host defense may not be entirely determined by the niche of the pathogen. A comprehensive approach that examines both humoral and cellular immunity could lead to better understanding of the immune response to M. tuberculosis.     

Limited Interleukin-18 Response in Salmonella-Infected Murine Macrophages and in Salmonella-Infected Mice

Optimal immune responses against an intracellular bacterial pathogen, such as Salmonella, involve the production of gamma interferon (IFN-gamma), which activates macrophages. It has recently been suggested that, interleukin-18 (IL-18), in addition to IL-12, contributes to the induction of IFN-gamma following infection. Given this hypothesis, an optimal host immune response against intracellular bacterial pathogens would include the induction of IL-18 secretion by macrophages due to Salmonella infection. We questioned whether Salmonella could induce macrophages to upregulate their expression of IL-18 mRNA and secretion of IL-18. With cultures of murine macrophages, we were surprised to find that infection by wild-type Salmonella dublin resulted in decreased expression of IL-18 mRNA and IL-18 secretion rather than an increase. Reduction of macrophage-derived IL-18 expression by wild-type Salmonella occurred early in the response, suggesting a direct effect. Furthermore, mice orally inoculated with wild-type Salmonella were shown to have reduced IL-18 mRNA expression at mucosal sites within hours postinoculation. Together these studies demonstrate Salmonella-induced reductions in IL-18 expression, suggesting that this intracellular pathogen may be capable of limiting a potentially protective immune response.     

Cytokine expression by attenuated intracellular bacteria regulates the immune response to infection: the Salmonella model

Attenuated Salmonella strains have shown excellent efficacy as mucosal vaccine delivery systems. In the present report, several recombinant strains of Salmonella enterica serovar Typhimurium, engineered to express defined murine cytokines, were used to study their potential immunoregulatory capacity in the mouse model of typhoid fever. Specifically, recombinant strains expressing IL-2 (known as GIDIL2) or TNF-alpha (GIDTNF) were compared with the parental, non-cytokine-secreting, strain (BRD509) for their ability to induce a variety of immune responses in susceptible BALB/c mice. Our findings indicate that bacterially-expressed cytokines are functional in vivo and do induce a unique pattern of responses, quite distinct from that induced by BRD509 organisms. Both the type and magnitude of specific immune parameters were affected. These included the capacity to induce an inflammatory response resulting in a state of profound splenomegaly and hepatomegaly, activation of individual immune cells (particularly macrophages and other myeloid lineage cells), and the induction of nitric oxide (NO) secretion. Furthermore, a structural analysis using light as well as electron microscopy was undertaken to examine the host cellular response to infection with the different bacterial strains. The results indicate that cytokine expression by the invading pathogen can dramatically influence host immunity from a very early stage following infection. These findings may well have important consequences for the potential utilization of bacterial vector-encoded cytokines in immunoregulation in different disease settings.     

Antigenic specificity of the mucosal antibody response to Moraxella catarrhalis in chronic obstructive pulmonary disease

Moraxella catarrhalis is an important human mucosal pathogen causing otitis media in children and lower respiratory tract infection in adults with chronic obstructive pulmonary disease (COPD). Little is known about the mucosal antibody response to M. catarrhalis in adults with COPD. In this study, 10 pairs of well-characterized sputum supernatant samples from adults with COPD who had acquired and subsequently cleared M. catarrhalis from their respiratory tracts were studied in detail in an effort to begin to elucidate potentially protective immune responses. Flow cytometry analysis was used to study the distribution of immunoglobulin isotypes in paired preacquisition and postclearance sputum samples. The results showed that immunoglobulin A (IgA) is the predominant M. catarrhalis-specific immunoglobulin isotype and that the sputum IgA contains a secretory component, indicating that it is locally produced at the mucosal site. Most patients made new sputum IgA responses to the adhesins UspA1 and Hag, along with the surface protein UspA2. A smaller proportion of patients made new sputum IgA responses to the iron-regulated proteins TbpB and CopB and to lipooligosaccharide. These results have important implications in understanding the mucosal immune response to M. catarrhalis in the setting of COPD and in elucidating the elements of a protective immune response.     

Indoleamine 2,3-dioxygenase, tryptophan catabolism, and Mycobacterium avium subsp. paratuberculosis: a model for chronic mycobacterial infections

Virulent mycobacterial infections progress slowly, with a latent period that leads to clinical disease in a proportion of cases. Mycobacterium avium subsp. paratuberculosis is an intracellular pathogen that causes paratuberculosis or Johne's disease (JD), a chronic intestinal disease of ruminants. Indoleamine 2,3-dioxygenase (IDO), an enzyme that regulates tryptophan metabolism, was originally reported to have a role in intracellular pathogen killing and has since been shown to have an important immunoregulatory role in chronic immune diseases. Here we demonstrate an association between increased IDO levels and progression to clinical mycobacterial disease in a natural host, characterizing gene expression, protein localization, and functional effects. IDO mRNA levels were significantly increased in M. avium subsp. paratuberculosis-infected monocytic cells. Levels of both IDO gene and protein expression were significantly upregulated within the affected tissues of sheep with JD, particularly at the site of primary infection, the ileum, of animals with severe multibacillary disease. Lesion severity was correlated with the level of IDO gene expression. IDO gene expression was also increased in the peripheral blood cells of M. avium subsp. paratuberculosis-exposed sheep and cattle. IDO breaks down tryptophan, and systemic increases were functional, as shown by decreased plasma tryptophan levels, which correlated with the onset of clinical signs, a stage well known to be associated with Th1 immunosuppression. IDO may be involved in downregulating immune responses to M. avium subsp. paratuberculosis and other virulent mycobacteria, which may be an example of the pathogen harnessing host immunoregulatory pathways to aid survival. These findings raise new questions about the host-mycobacterium interactions in the progression from latent to clinical disease.