血小板反应蛋白4通过诱导肿瘤相关巨噬细胞M2型极化促进肝癌细胞转移

血小板反应蛋白4 (thrombospondin 4, THBS4) 属于THBS家族成员,是细胞外基质分泌的蛋白质,参与调控细胞增殖、黏附及血管生成等多种生理过程。近来研究表明,机体在炎症刺激下加速产生THBS4并诱导巨噬细胞粘附与积累。我们的前期研究证实,THBS4在肝癌(hepatocellular carcinoma,HCC)中发挥促癌作用,但THBS4对肝癌免疫微环境的影响尚不明确。本文旨在分析THBS4通过诱导肿瘤相关巨噬细胞M2型极化,促进肝癌细胞转移的作用。通过肝癌条件培养基(HCC conditioned medium,HCM)模拟肿瘤微环境,发现在HCM作用下巨噬细胞中THBS4表达呈时间依赖性升高(P＜0.05);下调THBS4促使M1型巨噬细胞标志物IL-1β、CD86的表达升高(P＜0.01),而M2型标志物 IL-10和CD206表达降低(P＜0.01)。进一步通过Transwell共培养实验检测THBS4诱导的M2型巨噬细胞对肝癌转移的影响。将下调THBS4的M2型巨噬细胞(M2-TAMs)与HepG2肝癌细胞进行共培养。结果显示,下调THBS4的M2-TAMs明显抑制了HepG2细胞的侵袭和迁移能力(P均＜0.01)。综上所述,肿瘤微环境促进巨噬细胞中THBS4表达,THBS4可能通过诱导巨噬细胞M2型极化促进肝癌细胞侵袭转移。本文为探究THBS4诱导肝癌免疫微环境的建立提供了一些新的实验依据。     

靶向肿瘤相关巨噬细胞免疫治疗的研究进展

肿瘤相关巨噬细胞(TAMs)存在于肿瘤微环境中,分为经典活化的M1型和交替活化的M2型。M1型巨噬细胞通过释放促炎细胞因子来抑制肿瘤的生长,而M2型巨噬细胞通过促进肿瘤的增殖、血管生成和转移来促进肿瘤的进展。由于巨噬细胞对肿瘤的影响具有双重性,TAMs一直是肿瘤研究的热点。本文就TAMs的异质性和可塑性、TAMs与其他免疫细胞之间的串扰和TAMs对肿瘤的作用等问题进行了综述,并对TAMs的多种靶向治疗策略进行了总结和讨论。这些治疗策略包含抑制TAMs的招募、消耗TAMs以及调控TAMs的极化等方法和手段。这些研究有助于深入理解TAMs与肿瘤相互作用的机理,并为肿瘤的联合治疗提供借鉴和参考。     

维生素D3对黄颡鱼头肾极化分型的巨噬细胞影响

研究以黄颡鱼(Pelteobagrus fulvidraco)头肾巨噬细胞为研究对象,通过细菌脂多糖(LPS)和环磷酸腺苷(cAMP)分别诱导M1型和M2型极化,200 pmol/L维生素D₃孵育后对其形态学特征、生物学功能及极化相关基因的表达进行分析鉴定来确定维生素D₃在巨噬细胞极化中的调节作用。结果表明,维生素D₃能降低诱导后M1型和M2型巨噬细胞的死亡率,并增强巨噬细胞的吞噬活性。在M1型巨噬细胞中维生素D₃能够抑制活性氧(ROS)和炎症介质一氧化氮(NO)的产生,降低超氧阴离子自由基的活力,白介素1β(IL-1β)和肿瘤坏死因子-α(TNF-α)的表达水平显著降低(P<0.05);在M2型细胞中能够增加精氨酸酶的活性,显著增加白介素10(IL-10)和转化生长因子(TGF-β)的表达水平(P<0.05),最终抑制巨噬细胞向M1表型极化,促进巨噬细胞向M2表型极化,发挥抗炎作用;黄颡鱼头肾巨噬细胞中Nos-2和Arg-2分别是M1和M2巨噬细胞的生物标记基因。研究结果为进一步研究鱼...     

巨噬细胞极化的研究进展

巨噬细胞是一群表型和功能均具有高度异质性的免疫细胞。巨噬细胞通过清除并修复受损的细胞和基质来维护组织完整性。巨噬细胞在不同的组织微环境、不同病理条件下,可极化成不同的表型即M1型巨噬细胞(经典活化的巨噬细胞)和M2型巨噬细胞(替代活化的巨噬细胞)。本文将对不同巨噬细胞亚群在抗细菌感染、抗寄生虫感染、哮喘、动脉粥样硬化和肿瘤产生中起到的的保护或致病作用,以及调控巨噬细胞极化的机制进行综述。掌握巨噬细胞极化在不同疾病中的作用以及调控巨噬细胞极化的具体机制,将为疾病的预防、诊断、治疗及药物研发提供新策略。     

微RNA介导巨噬细胞极化的转录后调控

巨噬细胞极化是根据周围刺激环境做出表型调节的一个过程.一般极化为2个表型,分别为经典激活的M1巨噬细胞和替代激活的M2巨噬细胞.简而言之,M1巨噬细胞的特征是促炎和抗肿瘤;M2巨噬细胞是抗炎和促肿瘤.巨噬细胞极化被认为是人体生理和病理的关键调节器,其发挥作用的有效性依赖于关键因子的协调表达,而这些关键因子的表达在转录后...     

骨髓间充质干细胞培养液促进STAT3磷酸化诱导Raw264.7细胞向M2型极化

炎症性疾病的发生是当今临床医学攻克的重点。M1型巨噬细胞分泌炎症因子产生炎症,而M2型巨噬细胞分泌抑炎因子抑制炎症的发生。M1型巨噬细胞向M2型极化,则是从炎症状态转变成抑制炎症发生的状态,因此研究巨噬细胞向缓解炎症的M2型极化将有利于炎症性疾病的治疗。本研究利用骨髓间充质干细胞(BMSC)培养液处理已被脂多糖(LPS)诱导呈M1型的Raw264.7巨噬细胞,探究骨髓间充质干细胞培养液(BMSC-CM)对巨噬细胞向M2型极化的影响及其分子机制。提取来源于3周龄C57BL/6鼠的骨髓间充质干细胞;再收集BMSC-CM处理M1型的Raw264.7巨噬细胞;半定量PCR检测M1型标记基因[肿瘤坏死因子α(TNF-α)和诱导型一氧化氮合酶(INOS)]和M2型标记基因[精氨酸酶1(ARG-1)和转化生长因子β1(TGF-β1)]mRNA表达以及白介素10(IL-10)mRNA表达水平;Western蛋白质印迹法检测信号传导及转录激活蛋白3(STAT3)和磷酸化STAT3(p-STAT3)的表达。本研究发现,经过BMSC-CM培养后的M1型的Raw264.7巨噬细胞,其M2型相关指标ARG-1和TGF-β1 mRNA水平明显上升,并且IL-10 mRNA水平和p-STAT3蛋白水平也明显上升。这些结果说明,骨髓间充质干细胞培养液通过IL-10/STAT3信号通路促进STAT3磷酸化,诱导巨噬细胞Raw264.7细胞向M2型极化。     

病毒感染调控巨噬细胞极化分子机制的研究进展

固有免疫是机体抵御病原微生物入侵的第一道防线。巨噬细胞(macrophages, Mφ)在机体中分布广泛并具有十分活跃的生物学功能,在宿主抗病毒固有免疫应答过程中发挥重要作用。既往研究集中于Mφ的吞噬功能及抗原提呈作用,而近年来研究发现,不同活化模式的Mφ对病毒感染后机体的炎症反应具有双重调控作用,Mφ的极化状态与病毒感染性疾病的发生和转归关系密切。病毒感染急性期,Mφ向M1方向极化,M1型Mφ可促进炎症反应,辅助机体清除病原体,但其过度活化可引起细胞因子风暴,加重组织的免疫病理损伤;随着病毒感染相关疾病的进展,Mφ向M2方向极化,M2型Mφ可通过分泌多种抑炎因子发挥免疫调控作用,参与组织修复,亦与感染慢性化密切相关。不同种类的病毒感染机体后可以诱导Mφ向不同方向极化,但其具体调控机制目前尚不清楚。现就Mφ极化在病毒感染过程中的作用及其调控机制作一概述,为相关疾病的发病机制研究奠定理论基础,并为治疗策略的研发提供新的思路。     

姜黄素激活PPAR-γ通路改变巨噬细胞的极化状态

过氧化物酶体增殖物激活受体γ(peroxisome proliferator-activated receptorγ,PPAR-γ)通路是调节替换活化的(alternatively activated)M2型巨噬细胞极化的中心环节.姜黄素是PPAR-γ的天然激动剂,有着良好的抗炎作用.本研究通过建立巨噬细胞株的体外炎症模型,用姜黄素及PPAR-γ的特异性抑制剂GW9662对其进行干预,观察巨噬细胞株极化状态的改变.结果显示,姜黄素可以促使巨噬细胞向M2型极化,当特异性抑制PPAR-γ通路后,姜黄素促进巨噬细胞向M2型极化的作用受到抑制.结果表明,姜黄素可能是通过激动PPAR-γ通路促使巨噬细胞向M2型极化,为进一步研究姜黄素的抗炎机制及治疗慢性低度炎症相关的代谢性疾病提供了一个新的思路.     

M2型巨噬细胞极化及相关疾病的研究进展

巨噬细胞是固有免疫的重要成员,在机体防御病原微生物感染、肿瘤、过敏性疾病、代谢类疾病、组织损伤修复等发生发展过程中发挥着极其重要的作用。在微环境,尤其是多种细胞因子的影响下,巨噬细胞极化成M1/M2型巨噬细胞,表达相应的特异性基因,行使不同的功能。M1型巨噬细胞主要发挥促炎、杀菌及呈递抗原的功能,M2型巨噬细胞主要起抑炎、抗寄生虫感染和组织修复的作用。现总结人们对巨噬细胞极化的认识过程、M2型巨噬细胞的分类和其形成过程中起重要调控作用的信号分子,并着重讨论M2型巨噬细胞在相关疾病中的功能。     

JNK通路对M2巨噬细胞极化及其肿瘤效应的影响

探究了JNK通路对M2巨噬细胞极化及M2介导的促肿瘤效应的影响。构建单核细胞THP1来源M2 巨噬细胞模型(THP1-M2),将细胞分为3组: 用PMA 诱导的未活化巨噬细胞组(M0),用PMA、IL-4处理及阴性干扰(DMSO)的M2型巨噬细胞组(M2),用特异性抑制剂阻断JNK通路的M2 型巨噬细胞组(M2-JNKI)。实时荧光定量PCR检测M2 表型marker基因的表达;免疫蛋白印迹法检测M2 表型marker蛋白水平;细胞划痕试验检测巨噬细胞迁移能力;流式细胞数检测786O及OSRC2凋亡。结果与THP1-M2组相比,阻断JNK通路的M2组M2表型marker表达明显下降,同时其细胞迁移能力也呈下降趋势。且阻断JNK通路后,M2巨噬细胞抑制肾癌细胞凋亡的能力减弱。结果表明,抑制JNK通路后,M2巨噬细胞极化状态受损,其促肿瘤效应可转变为抗肿瘤效应。     

巨噬细胞的极化及其意义

表型可变性和功能多样性是单个核吞噬细胞的重要特征。近年来巨噬细胞的极化受到关注。一般认为极化巨噬细胞是单核细胞活化后一系列功能状态两个极端。而它的分化受到各种微环境信号的诱导与调节。极化的巨噬细胞能够进一步影响局部免疫反应,与各种因子协同作用调节病原体微生物感染结局和肿瘤免疫,参与免疫调节,组织修复重塑过程。对巨噬细胞亚型诱导因素及功能的研究将有助于了解免疫反应的调节机制。     

Absent in melanoma 2-mediating M1 macrophages facilitate tumor rejection in renal carcinoma

Absent in melanoma 2 (AIM2) as an immune regulator for the regulation of tumor-associated macrophages (TAMs) function is unclear in tumor development. Here, the AIM2 function was investigated in TAMs-mediated malignant behaviors of renal carcinoma. The correlation analysis result showed that the AIM2 expression in TAMs was negatively correlated with the percentages of M2-like polarization phenotype in human or murine renal cancer specimens. By the cocultured assay with bone marrow-derived macrophages (BMDMs) and Renca cells, overexpression of AIM2 in macrophages enhanced the inflammasome activation and reversed the phenotype from M2 to M1. Compared with BMDMs-Ctrl cocultured group, BMDMs-AIM2 cocultured group showed reduced tumor cell proliferation and migration. The blockade of inflammasome activation by the inhibitor Ac-YVAD-CMK abrogated AIM2-mediated M1 polarization and the inhibition of tumor cell growth. To evaluate the therapeutic efficacy of AIM2-mediated M1 macrophages in vivo, BMDMs-AIM2 were intravenously injected into subcutaneous Renca-tumor mice. The results showed that the infiltration of M1 TAMs was increased and tumor growth was suppressed in BMDMs-AIM2-treated mice when compared with BMDMs-Ctrl-treat mice. Accordingly, the blockade of inflammasome activation reduced the anti-tumor activities of BMDMs-AIM2. Moreover, the lung metastases of renal carcinoma were suppressed by the administration of BMDMs-AIM2 accompanied with the reduced tumor foci. These results demonstrated that AIM2 enhanced TAMs polarization switch from anti-inflammatory M2 phenotypy to pro-inflammatory M1 through inflammasome signaling activation, thus exerting therapeutic intervention in renal carcinoma models. Our results provide a possible molecular mechanism for the modulation of TAMs polarization in tumor microenvironment and open a new potential therapeutic approach for renal cancer.     

Clotrimazole presents anticancer properties against a mouse melanoma model acting as a PI3K inhibitor and inducing repolarization of tumor-associated macrophages

The immune system is a key component of tumorigenesis, with the latter promoting the development of cancer, its progression and metastasis. In fact, abundant infiltration of tumor-associated macrophages (TAM), which are M2-like macrophages, has been associated with a poor outcome in most types of cancers. Here, we show that lactate produced by murine melanoma B16F10 cells induces an M2-like profile in cultured macrophages. Further, we demonstrate that clotrimazole (CTZ), an off-target anti-tumor drug, abolishes lactate effects on the activation of macrophages and induces the expression of M1-like markers. We show that clotrimazole has cytotoxic effects on tumor cells by negatively modulating PI3K, which inhibits glycolytic metabolism and leads to a diminishing lactate production by these cells. These effects are more pronounced in cancer cells exposed to conditioned media of M2-polarized macrophages. Moreover, clotrimazole inhibits tumor growth in a murine model of implanted melanoma, reduces lactate content in a tumor microenvironment and decreases vascular endothelial growth factor expression. Finally, clotrimazole drastically diminishes TAM infiltration in the tumors, thereby inducing M1 polarization. Collectively, these findings identify a new antitumor mechanism of clotrimazole by modulating the tumor microenvironment (TME), particularly the activation and viability of TAM.     

Prostaglandin E3 attenuates macrophage-associated inflammation and prostate tumour growth by modulating polarization

Alternative polarization of macrophages regulates multiple biological processes. While M1-polarized macrophages generally mediate rapid immune responses, M2-polarized macrophages induce chronic and mild immune responses. In either case, polyunsaturated fatty acid (PUFA)-derived lipid mediators act as both products and regulators of macrophages. Prostaglandin E₃ (PGE₃) is an eicosanoid derived from eicosapentaenoic acid, which is converted by cyclooxygenase, followed by prostaglandin E synthase successively. We found that PGE₃ played an anti-inflammatory role by inhibiting LPS and interferon-γ-induced M1 polarization and promoting interleukin-4-mediated M2 polarization (M2a). Further, we found that although PGE₃ had no direct effect on the growth of prostate cancer cells in vitro, PGE₃ could inhibit prostate cancer in vivo in a nude mouse model of neoplasia. Notably, we found that PGE₃ significantly inhibited prostate cancer cell growth in a cancer cell-macrophage co-culture system. Experimental results showed that PGE₃ inhibited the polarization of tumour-associated M2 macrophages (TAM), consequently producing indirect anti-tumour activity. Mechanistically, we identified that PGE₃ regulated the expression and activation of protein kinase A, which is critical for macrophage polarization. In summary, this study indicates that PGE₃ can selectively promote M2a polarization, while inhibiting M1 and TAM polarization, thus exerting an anti-inflammatory effect and anti-tumour effect in prostate cancer.     

Photodynamic therapy exploiting the anti-tumor activity of mannose-conjugated chlorin e6 reduced M2-like tumor-associated macrophages

M2-like tumor-associated macrophages (M2-TAMs) in cancer tissues are intimately involved in cancer immunosuppression in addition to growth, invasion, angiogenesis, and metastasis. Hence, considerable attention has been focused on cancer immunotherapies targeting M2-TAMs. However, systemic therapies inhibit TAMs as well as other macrophages important for normal immune responses throughout the body. To stimulate tumor immunity with fewer side effects, we targeted M2-TAMs using photodynamic therapy (PDT), which damages cells via a nontoxic photosensitizer with harmless laser irradiation. We synthesized a light-sensitive compound, mannose-conjugated chlorin e6 (M-chlorin e6), which targets mannose receptors highly expressed on M2-TAMs. M-chlorin e6 accumulated more in tumor tissue than normal skin tissue of syngeneic model mice and was more rapidly excreted than the second-generation photosensitizer talaporfin sodium. Furthermore, M-chlorin e6 PDT significantly reduced the volume and weight of tumor tissue. Flow cytometric analysis revealed that M-chlorin e6 PDT decreased the proportion of M2-TAMs and increased that of anti-tumor macrophages, M1-like TAMs. M-chlorin e6 PDT also directly damaged and killed cancer cells in vitro. Our data indicate that M-chlorin e6 is a promising new therapeutic agent for cancer PDT.     

Pomalidomide Shows Significant Therapeutic Activity against CNS Lymphoma with a Major Impact on the Tumor Microenvironment in Murine Models

Primary CNS lymphoma carries a poor prognosis. Novel therapeutic agents are urgently needed. Pomalidomide (POM) is a novel immunomodulatory drug with anti-lymphoma activity. CNS pharmacokinetic analysis was performed in rats to assess the CNS penetration of POM. Preclinical evaluation of POM was performed in two murine models to assess its therapeutic activity against CNS lymphoma. The impact of POM on the CNS lymphoma immune microenvironment was evaluated by immunohistochemistry and immunofluorescence. In vitro cell culture experiments were carried out to further investigate the impact of POM on the biology of macrophages. POM crosses the blood brain barrier with CNS penetration of ~ 39%. Preclinical evaluations showed that it had significant therapeutic activity against CNS lymphoma with significant reduction in tumor growth rate and prolongation of survival, that it had a major impact on the tumor microenvironment with an increase in macrophages and natural killer cells, and that it decreased M2-polarized tumor-associated macrophages and increased M1-polarized macrophages when macrophages were evaluated based on polarization status. In vitro studies using various macrophage models showed that POM converted the polarization status of IL4-stimulated macrophages from M2 to M1, that M2 to M1 conversion by POM in the polarization status of lymphoma-associated macrophages is dependent on the presence of NK cells, that POM induced M2 to M1 conversion in the polarization of macrophages by inactivating STAT6 signaling and activating STAT1 signaling, and that POM functionally increased the phagocytic activity of macrophages. Based on our findings, POM is a promising therapeutic agent for CNS lymphoma with excellent CNS penetration, significant preclinical therapeutic activity, and a major impact on the tumor microenvironment. It can induce significant biological changes in tumor-associated macrophages, which likely play a major role in its therapeutic activity against CNS lymphoma. POM should be further evaluated in clinical trials.     

Autophagy-mediated regulation of macrophages and its applications for cancer

Autophagy is a highly conserved homeostatic pathway that plays an important role in tumor development and progression by acting on cancer cells in a cell-autonomous mechanism. However, the solid tumor is not an island, but rather an ensemble performance that includes nonmalignant stromal cells, such as macrophages. A growing body of evidence indicates that autophagy is a key component of the innate immune response. In this review, we discuss the role of autophagy in the control of macrophage production at different stages (including hematopoietic stem cell maintenance, monocyte/macrophage migration, and monocyte differentiation into macrophages) and polarization and discuss how modulating autophagy in tumor-associated macrophages (TAMs) may represent a promising strategy for limiting cancer growth and progression.     

Doxycycline Inhibits Polarization of Macrophages to the Proangiogenic M2-type and Subsequent Neovascularization

Macrophages occur along a continuum of functional states between M1-type polarized macrophages with antiangiogenic and antitumor activity and M2-type polarized macrophages, which have been implicated to promote angiogenesis and tumor growth. Proangiogenic M2-type macrophages promote various pathologic conditions, including choroidal neovascularization in models of neovascular age-related macular degeneration, or certain cancers, such as glioblastoma multiforme. Thus, a potential novel therapeutic approach to target pathological angiogenesis in these conditions would be to inhibit the polarization of macrophages toward the proangiogenic M2-type. However, no pharmacological inhibitors of M2-type macrophage polarization have been identified yet. Here we performed an unbiased pharmacological and small chemical screen to identify drugs that inhibit proangiogenic M2-type macrophage polarization and block pathologic macrophage-driven neovascularization. We identified the well tolerated and commonly used antibiotic doxycycline as a potent inhibitor of M2-type polarization of macrophages. Doxycycline inhibited, in a dose-dependent manner, M2-type polarization of human and bone marrow-derived mouse macrophages without affecting cell viability. Furthermore, doxycycline inhibited M2-type macrophage polarization and subsequent neovascularization in vivo in a laser injury model of choroidal neovascularization. Thus, doxycycline could be used to enhance current antiangiogenic treatment approaches in various conditions that are promoted by proangiogenic M2-type macrophages, including neovascular age-related macular degeneration and certain cancers.