不同刺激因子对小胶质细胞系N9极化的影响

目的:揭示不同的炎症因子在体外培养的条件下,对小胶质细胞系N9不同极化方向的影响。方法:将小鼠小胶质细胞系N9细胞分为四组:空白对照组(正常培养基)、LPS组、LPS+INF-γ组、IL-4组。各组细胞在上述刺激条件下培养24 h,以及撤去上述刺激条件,继续培养24 h后,分别提取各组细胞总RNA,利用荧光实时定量PCR的方法检测各组N9细胞表达的细胞因子在mRNA水平的变化;利用Western blot检测各组N9细胞极化相关蛋白的变化。结果:在LPS以及LPS+INF-γ刺激条件下培养24 h,M1型巨噬细胞特异性标记物iNOS和CD86的mRNA及蛋白表达水平在N9细胞中明显升高,并且LPS+INF-γ刺激组升高更为明显;而撤除LPS+INF-γ刺激因子后继续培养24 h,N9细胞表达的iNOS和CD86 mRNA的水平均有下调,但仍明显高于对照组。在IL-4刺激条件下培养24 h,M2型巨噬细胞特异性标记物Arg1和CD206的mRNA及蛋白表达水平均在N9细胞中明显上调;同样撤除IL-4刺激因子后,继续培养24 h,N9细胞表达的ArgI和CD206的mRNA水平均有明显下调,但仍然高于对照组。此时ArgI的蛋白表达变化也与其mRNA水平的变化相符。结论:小胶质细胞的分型分化具有明显的细胞因子依赖性,LPS和LPS+INF-γ可使N9小胶质细胞向M1型巨噬细胞方向极化;IL-4可促使N9小胶质细胞向M2型巨噬细胞方向极化;LPS与IFN-γ二者在极化N9小胶质细胞中具有协同作用。极化后的N9细胞在去除刺激因子后,仍可在一定程度上维持其极化状态。     

Aire 对巨噬细胞极化影响的研究

目的:研究自身免疫调节因子(Aire)对巨噬细胞极化的影响。方法:分别用LPS、IL-4 以及LPS 联合免疫复合物刺激小鼠单核巨噬细胞系RAW264郾7 细胞、稳定表达GFP-Aire 的RAW264.7 细胞(A33-3) 细胞和稳定表达GFP 的RAW264.7 细胞(C1-6),使其向M1(LPS)、M2a(IL-4)和M2b(LPS 联合免疫复合物)型巨噬细胞极化。通过Real-time PCR 检测各组细胞中M1 型巨噬细胞特征分子IL-1、iNOS 和IL-6,M2a 型特征分子Arg-1 和M2b 型特征分子IL-10 的表达水平,研究Aire 对各种类型巨噬细胞极化的影响。结果:LPS 在0.5 g/ ml 浓度时,RAW264.7 细胞中M1 型巨噬细胞产物IL-1 、iNOS和IL-6 基因表达量最高;而IL-4 以及LPS 联合免疫复合物的刺激作用有显著的剂量依赖性,都在浓度最高时RAW264.7 细胞中Arg1(M2a)和IL-10(M2b)基因表达量最高。LPS 刺激后,A33-3 细胞中IL-1 和iNOS 表达水平明显高于C1-6 细胞,IL-6 则相反;IL-4 及LPS 联合免疫复合物刺激后,A33-3 细胞中Arg1 和IL-10 的表达水平明显低于C1-6 细胞。结论:Aire 可能促进巨噬细胞向M1 极化,同时抑制其向M2a 和M2b 极化。     

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。     

小鼠巨噬细胞功能极化可塑性的初步探讨

目的通过鉴定小鼠骨髓来源巨噬细胞(bone marrow-derived macrophages,BMDM)的功能表型,从而研究巨噬细胞功能极化的可塑性及其内在机制。方法采用流式细胞术检测体外诱导分化的小鼠骨髓来源巨噬细胞纯度;采用荧光定量PCR技术检测由RAW264.7极化的M1、M2巨噬细胞中M1、M2特定标记基因的表达来鉴定RAW264.7的功能状态;小鼠BMDM极化为M1、M2巨噬细胞时,荧光定量PCR技术检测M1、M2中特定标记基因TNF-α、IL-6、Arginase、Fizz-1 mRNA水平的表达,组蛋白去乙酰化酶抑制剂Trichostatin A(TSA)、DNA去甲基化酶抑制剂5-氮杂-2-脱氧胞(Aza)刺激M1、M2巨噬细胞后,检测TNF-α、IL-6、Arginase、Fizz-1 mRNA水平表达的变化。结果 RAW264.7细胞经LPS刺激8 h极化为M1巨噬细胞;RAW264.7细胞经IL-4体外刺激24 h极化为M2巨噬细胞。小鼠BMDM在LPS、IL-4刺激下,分别极化为M1、M2巨噬细胞,改变体外刺激条件,M1巨噬细胞可重分化为M2样巨噬细胞,M2巨噬细胞可重分化为M1样巨噬细胞,M1样巨噬细胞和M2巨噬细胞是介于M1、M2中间状态的2种巨噬细胞;药物TSA、Aza的加入使M1、M2中特定标记基因TNF-α、IL-6、Arginase、Fizz-1 mRNA水平表达增加。结论巨噬细胞的功能极化具有可塑性,巨噬细胞的极化可能与染色质状态的改变有关。     

花青素Cyanidin-3-O-glucoside 对脂多糖和白介素-4 刺激的小鼠骨髓巨噬细胞极化的影响

目的:探讨树莓花青素矢车菊素-3-O-葡萄糖苷(C3G)对小鼠骨髓巨噬细胞(BMDM)炎性细胞因子表达和生成的影响,进而了解C3G调控BMDM极化的机制。方法:取小鼠骨髓细胞,用100 ng/ml巨噬细胞集落刺激因子(M-CSF)诱导为BMDM。将诱导成功的BMDM分为两组,一组BMDM经C3G预处理12 h,再与1μg/ml脂多糖(LPS)共处理12 h;另一组BMDM经C3G和20 ng/ml IL-4共处理24 h。采用MTT法检测不同浓度C3G对BMDM细胞活性的影响,qRT-PCR法和ELISA法分别检测BMDM促炎细胞介质IL-6、IL-1β、TNF-α、MCP-1、i NOS和抑炎细胞介质IL-10、Arg-1的mRNA水平和蛋白水平。结果:MTT检测结果显示1、5、10、15、20、25和30μg/ml的C3G对BMDM细胞活力无明显可见的影响,qRT-PCR和ELISA分析结果显示1μg/ml LPS显著上调BMDM促炎细胞介质的表达,20 ng/ml IL-4显著上调BMDM抑炎细胞介质的表达; 5、10和20μg/ml C3G处理既可明显降低LPS刺激的BMDM促炎细胞介质表达,也可增强IL-4刺激的BMDM抑炎细胞介质表达。结论:C3G通过下调巨噬细胞促炎细胞介质表达和上调巨噬细胞抑炎细胞介质表达,调控BMDM极化,并影响巨噬细胞的炎性反应。     

小鼠巨噬细胞极化与焦亡的关系研究

目的：探讨小鼠巨噬细胞极化与焦亡的关系。方法：RAW264.7小鼠巨噬细胞分为3组：M0组、M1组和M2组，M1组予以LPS和IFN-γ诱导，M2组予以IL-4和IL-13诱导，M0组予以等量PBS作为对照。流式细胞术检测细胞表型及焦亡，PI染色观察焦亡细胞定性，LDH检测细胞活性，ELISA检测炎症因子IL-1β、IL-18水平，RT-qPCR及Western blot检测caspase-1、caspase-11和GSDMD mRNA和蛋白水平。结果：倒置显微镜观察到极化后M1与M0、M2巨噬细胞形态差异显著；流式细胞术检测M1、M2巨噬细胞特异性分子结果证明诱导极化成功；与M0相比，M1、M2组炎症因子IL-1β、IL-18水平均升高（P<0.05）;M1组PI染色阳性率高于M0和M2组；与M0和M2相比，M1型巨噬细胞活化的caspase-1、caspase-11和GSDMD mRNA和蛋白表达增加。结论：LPS+IFN-γ和IL-4+IL-13可分别成功诱导M0型巨噬细胞向M1和M2型极化，且极化后的M1型巨噬细胞形态与M0、M2型差异显著；M0、M1和M2型巨噬细胞均可...     

DNA羟甲基化酶10-11转位蛋白2(TET2)抑制小鼠巨噬细胞活化和极化北大核心CSCD

目的研究DNA羟甲基化酶10-11转位蛋白2(TET2)在巨噬细胞活化和极化中的作用。方法体外培养RAW264.7巨噬细胞并以100 ng/m L脂多糖(LPS)刺激0、1、2、4、6 h,采用实时定量PCR检测TET2 m RNA表达水平;利用小干扰RNA(si RNA)敲低TET2表达,并通过实时定量PCR和Western blot法检测干涉效率;利用si RNA下调TET2表达48 h后,LPS刺激活化4 h,通过实时定量PCR和ELISA检测白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)、IL-12的m RNA水平;下调TET2后,用LPS和γ干扰素(IFN-γ)或IL-4刺激巨噬细胞发生M1型极化或M2型极化,通过实时定量PCR检测M1型巨噬细胞极化标志物TNF-α、诱导型一氧化氮合酶(i NOS)、IL-12和M2型极化标志物甘露糖受体(MR)、精氨酸酶1(Arg-1)、类几丁质酶3样分子1(Ym1)的m RNA水平。结果 LPS刺激巨噬细胞后,TET2 m RNA增加,并在2 h达到峰值;特定si RNA能有效降低TET2的表达;敲低TET2后,LPS诱导活化的巨噬细胞TNF-α、IL-6和IL-12的m RNA水平均升高;敲低TET2后,TNF-α、i NOS、IL-12和MR、Arg-1、Ym1的m RNA水平在相应刺激后均发生上调。结论 TET2具有抑制LPS诱导的巨噬细胞活化的作用,并在巨噬细胞M1型和M2型极化中发挥抑制作用。     

NT-3促进脂多糖诱导的M1型巨噬细胞向M2表型极化

目的探讨神经营养素-3(NT-3)能否促进脂多糖(LPS)诱导的M1型巨噬细胞向M2型巨噬细胞极化。方法体外培养小鼠RAW264.7巨噬细胞株,分为LPS组和LPS+NT-3组。用脂多糖(100 ng/ml)刺激12h后,撤掉LPS培养基,冲洗,分别加入基础培养基和含有NT-3(40 ng/ml)的基础培养基,培养24 h后,全部置换成基础培养基培养24 h,收集上清与细胞。固定后的细胞分别做CD68/CCR7(M1型细胞标记物)、CD68/CD206(M2型细胞标记物)、CD68/Trk C免疫荧光双标染色。用酶联吸附试验(ELISA)检测上清中TNF-α和IL-10水平。结果免疫荧光细胞化学染色显示,LPS刺激后的巨噬细胞表达NT-3的受体Trk C。LPS组可观察到较多的M1型细胞和较少的M2型细胞。LPS+NT-3组可观察到M1型细胞数减少,而M2型细胞数增多。与LPS组比较,LPS+NT-3组的M1型巨噬细胞比例降低,同时M2型巨噬细胞比例增加(P<0.01)。ELISA结果显示,与LPS组比较,LPS+NT-3组上清中TNF-α的水平明显下降(P<0.01),IL-10的水平相对升高但是差异不明显(P>0.05)。结论 NT-3促进M1型巨噬细胞向M2型极化可能通过与其受体Trk C结合发挥作用,进而减少促炎因子TNF-α的分泌。     

肝素通过TLR4减少脂多糖刺激的人内皮细胞IL-8表达

目的:观察肝素对脂多糖(lipopolysaccharide, LPS)刺激的人内皮细胞白细胞介素8(interleukin-8,IL-8)水平的影响,并探讨Toll样受体4(Toll-like receptor 4,TLR 4)在其中的可能影响。方法:用LPS(10 mg/L)刺激人肺微血管内皮细胞诱导损伤,肝素治疗组提前15 min分别加入100 U/L及10³ U/L普通肝素,正常对照组加入等量磷酸盐缓冲液。分别在刺激2、6、12 h收集细胞上清,采用酶联免疫吸附法测定上清中IL-8的浓度。在刺激2、6、12 h收集细胞提取RNA,应用实时荧光定量聚合酶链反应检测各组细胞中IL-8、CD14及TLR4 mRNA水平变化。结果:与正常对照组比较,LPS刺激组IL-8 mRNA水平增高,6 h达到高峰,其蛋白水平于12 h达到高峰。LPS刺激下TLR4 mRNA水平增高,6 h达到高峰,肝素降低其水平,差异有统计学意义(P＜0.05)。未检测到CD14 mRNA的表达。结论:LPS刺激下人肺微血管内皮细胞IL-8表达增加。肝素可能通过调节TLR4降低IL-8的水平,从而发挥保护作用。     

脐带间充质干细胞对小胶质细胞活化表型的调节

目的:探讨脐带间充质干细胞(hUC-MSCs)是否以外分泌的方式调节小胶质细胞M1/M2极化表型,并且探讨其机制。方法:提取原代脐带间充质干细胞,并制备含有hUC-MSCs分泌的全部营养因子的条件培养基(hUC-MSCs-CM)。实验分为:空白对照组,单纯LPS刺激组,单纯hUC-MSCs-CM刺激组,LPS、hUC-MSCs-CM共刺激组,刺激24 h后收集上清和蛋白。ELISA方法检测上清中TNF-α、IL-6浓度,Western blot检测CD86、精氨酸酶1(Arg1)、PI3K的蛋白表达量。结果:①LPS诱导BV2细胞分泌TNF-α、IL-6因子增多,LPS、hUC-MSCs-CM共刺激组与LPS组相比,TNF-α、IL-6表达明显降低(P 0. 05);②LPS刺激组BV2细胞M1型标志物CD86表达明显增多,hUC-MSCs-CM共刺激组与LPS组相比CD86表达降低(P 0. 05)。LPS、hUC-MSCs-CM共刺激组M2型标志物Arg1表达增多(P 0. 05);③LPS、hUC-MSCs-CM共刺激组上调PI3K磷酸化水平(P 0. 05)。结论:①hUC-MSCs以外分泌的方式抑制小胶质细胞炎性因子的分泌;②hUC-MSCs促进活化的小胶质细胞由M1型向M2型转化,其机制可能与激活PI3K/AKT通路相关。     

Regulation of CRIg expression and phagocytosis in human macrophages by arachidonate, dexamethasone, and cytokines

Although the importance of the macrophage complement receptor immunoglobulin (CRIg) in the phagocytosis of complement opsonized bacteria and in inflammation has been established, the regulation of CRIg expression remains undefined. Because cellular activation during inflammation leads to the release of arachidonate, a stimulator of leukocyte function, we sought to determine whether arachidonate regulates CRIg expression. Adding arachidonate to maturing human macrophages and to prematured CRIg(+) macrophages caused a significant decrease in the expression of cell-surface CRIg and CRIg mRNA. This effect was independent of the metabolism of arachidonate via the cyclooxygenase and lipoxygenase pathways, because it was not inhibited by the nonsteroidal anti-inflammatory drugs indomethacin and nordihydroguaiaretic acid. Studies with specific pharmacological inhibitors of arachidonate-mediated signaling pathways showed that protein kinase C was involved. Administration of dexamethasone to macrophages caused an increase in CRIg expression. Studies with proinflammatory and immunosuppressive cytokines showed that IL-10 increased, but interferon-γ, IL-4, and transforming growth factor-β1 decreased CRIg expression on macrophages. This down- and up-regulation of CRIg expression was reflected in a decrease and increase, respectively, in the phagocytosis of complement opsonized Candida albicans. These data suggest that a unique inflammatory mediator network regulates CRIg expression and point to a mechanism by which arachidonate and dexamethasone have reciprocal effects on inflammation.     

大鼠脑缺血再灌注损伤后极化的小胶质细胞排斥性导向分子A的表达变化

目的 探讨大鼠大脑中动脉缺血再灌注损伤后极化的小胶质细胞排斥性导向分子A（RGMa）的表达变化。 方法 取雄性SD大鼠30只,随机分成对照组,缺血再灌注损伤7 d、14 d模型组（I/R）,采用线栓法制作大鼠大脑中动脉缺血再灌注损伤模型(tMCAO);Real-time PCR检测M1、M2型小胶质细胞标记分子白细胞介素-1β（IL-1β）、诱导性一氧化氮合酶（iNOS）、精氨酸酶1（Arg-1）及CD206 mRNA的表达;免疫荧光检测缺血区小胶质细胞RGMa的表达;体外培养小胶质细胞,分别用M1或M2型小胶质细胞的诱导物脂多糖（LPS）或IL-4诱导24 h后,利用Real-time PCR检测M1、M2型小胶质细胞标记分子IL-1β、iNOS、Arg-1、CD206 mRNA的表达;Western blotting检测M1、M2型小胶质细胞上RGMa的表达。 结果 缺血再灌注损伤后7 d、14 d,M1、M2型小胶质细胞的标记分子表达增加。缺血后7 d、14 d激活的小胶质细胞上RGMa大量表达。RGMa在体外培养的LPS诱导极化的M1型小胶质细胞和IL-4诱导极化的M2型小胶质细胞上表达均显著增加。 结论 大鼠大脑中动脉缺血再灌注损伤后,RGMa在缺血区M1型和M2型极化的小胶质细胞上均大量表达,RGMa可能在小胶质细胞激活极化过程中发挥重要作用。RGMa可能是缺血性脑卒中治疗的新靶点。     

M1和M2型巨噬细胞表型的比较分析

通过对M1和M2型巨噬细胞表型相关指标的比较分析,评价各鉴定巨噬细胞类型的表型指标及其意义。按常规方法以IFN-γ及LPS将骨髓来源巨噬细胞诱导成M1型巨噬细胞,以IL-4诱导出M2型巨噬细胞。分别以RT-PCR和酶活性定量方法检测精氨酸代谢相关酶的表达和活性;以ELISA检测IL-12和IL-10的分泌;以FACS检测巨噬细胞膜分子的表达。结果显示:M1型巨噬细胞诱导性一氧化氮合酶(inducible nitric oxide synthase,iNOS)表达和活性水平较未刺激组明显升高,IL-12产生显著增加,CD16/32表达上调;而M2型巨噬细胞I型精氨酸酶(arginase 1,Arg-1)的表达水平和酶活性较未刺激巨噬细胞显著提高,IL-10分泌轻度增加,并且表达高水平的CD206和DECTIN-1。表型比较分析结果表明,iN-OS表达和活性、IL-12的分泌和膜蛋白CD16/32可用于鉴定M1型巨噬细胞,而Arg-1、CD206和DECTIN-1是鉴定M2型巨噬细胞较为理想的表型指标。     

PI3K/AKT信号通路在SjCystatin诱导M2巨噬细胞分化过程中的影响

目的:进一步确定日本血吸虫半胱氨酸蛋白酶抑制剂(Sj Cystatin)诱导M2巨噬细胞分化的亚型及相关机制。方法:用ELISA、RT-q PCR或Western blot法测定IL-10、IL-12、巨噬细胞亚型表面标志物LIGHT(M2b)及Arg-1(M2a+M2c)的表达;用Western blot法测定AKT的磷酸化水平。结果:Sj Cystatin处理组在6 h、12 h和24h时IL-10表达量持续增加;处理12 h,LIGHT的mRNA和蛋白表达量增加但Arg-1的mRNA和蛋白表达量降低;AKT磷酸化水平增加。PI3K/AKT抑制剂处理组IL-10的释放量在12 h和24 h持续降低;24 h,LIGHT的mRNA和蛋白表达量降低但Arg-1的mRNA和蛋白表达量增加;AKT的磷酸化水平减少。结论:Sj Cystatin促进了活化的M2巨噬细胞分化为M2b亚型巨噬细胞,并且PI3K/AKT信号通路参与了这一过程。     

Carbon Monoxide-Releasing Molecule-3 Regulates the Polarization of Lipopolysaccharide-Induced Macrophages

Macrophages show two main phenotypes, the M1-type (pro-inflammatory) and the M2-type (anti-inflammatory). The purpose of this research was to investigate the regulatory effect of carbon monoxide releasing molecule-3 (CORM-3) on LPS-induced macrophage polarization. LPS-induced RAW264.7 cells were exposed to CORM-3 for 24 h. Polarization of cells was checked by flow cytometry; expression of M1 or M2 macrophage-related factors and NF-κB signaling factors was examined by RT-PCR, ELISA, and Western blot. Male C57 mice were divided into three groups: normal group; periodontitis group, where experimental periodontitis was established in mice; LPS+CORM-3 group, where mice with experimental periodontitis were treated with CORM-3. Polarization of macrophages and the expression of M1 or M2 macrophage-related factors were detected by immunofluorescence, ELISA, and RT-PCR. CORM-3 significantly reduced M1 macrophage proportion, but increased M2 proportion in LPS-stimulated cells. Accordingly, CORM-3 significantly suppressed the expression of M1 macrophage-related TNF-α, iNOS, IL-1β, and IL-6, but promoted M2-related IL-10 and Arg-1. The expression of p-p65, p-p50, and p-IκB induced with LPS was inhibited by CORM-3. In vivo experiments indicated that CORM-3 induced more M2 macrophages in periodontal tissues in mice with experimental periodontitis. The expression of M1 macrophage-related factor in periodontitis was inhibited, but the expression of M2-related factors was increased by CORM-3. CORM-3 inhibits macrophage polarization to pro-inflammatory M1-type and promotes to anti-inflammatory M2-type, which provides scientific basis for the application of CORM-3 in the treatment of periodontitis.

     

免疫补体调节蛋白C1 抑制物对巨噬细胞极化的作用

目的:研究免疫补体调节蛋白C1 抑制物(C1INH)调节巨噬细胞向经典活化巨噬细胞(M1)和选择性激活巨噬细胞(M2)的极化作用。方法:首先从人血中分离单核细胞后,单核细胞在巨噬细胞集落刺激因子(M-CSF)或粒细胞-巨噬细胞集落刺激因子(GM-CSF)作用下转变为静态巨噬细胞;静态巨噬细胞在干扰素-γ(IFN-γ)或白细胞介素4(IL-4)+IL-13 刺激作用下分别转化为M1 或M2。通过流式细胞仪观察C1INH 对巨噬细胞CD14、CD163、CD206 表型标志物的作用;应用RT-PCR 分析C1INH 对巨噬细胞细胞因子、趋化因子、相关酶基因表达影响;利用Western blot 方法,探讨在炎症条件下C1INH 对巨噬细胞CD14 结合Toll 样受体4(TLR4)的影响。结果:C1INH 抑制M-CSF 源性M1 的CD14、CD163 和GM-CSF 源性M2 的CD206 表型。C1INH 减少M1 的肿瘤坏死因子(TNF-α)和IL-6 表达,而增加M2 的15 脂氧合酶(ALOX15)和IL-10 表达。C1INH 抑制M1 的诱导型一氧化氮合酶(iNOS)mRNA,而提高M2 的精氨酸酶1(Arg1)mRNA 表达。C1INH 促进M1 的杀菌活性和M2 对菌的吞噬功能。C1INH 阻断CD14-TLR4 介导信号传导通路。结论:C1INH 调节巨噬细胞极化。     

In vitro modulation of C1q mRNA expression and secretion by interleukin-1, interleukin-6, and interferon-gamma in resident and stimulated murine peritoneal macrophages

The complement system plays an important role in the humoral immune response. Activation of the classical complement pathway is mediated by its subcomponent, C1q. Among the main C1q-synthesising tissues, macrophages have been attributed as a source of particular importance. We investigated the effects of cytokines (IL-1, IL-6 and Interferon-gamma) on local C1q mRNA expression and C1q secretion in resident and in thioglycollate-stimulated murine peritoneal macrophages in vitro. The macrophages were isolated from murine peritoneal lavage fluid, maintained in culture and incubated with the cytokines. Among the cytokines, only IL-6 had a stimulatory effect on C1q production (25% increase vs. control), while IL-1 and interferon-gamma had an inhibitory effect (50% decrease vs. control), especially in stimulated peritoneal macrophages in culture. Our data suggest that C1q production in macrophages may be differentially regulated by inflammatory cytokines such as IL-1, IL-6 and interferon-gamma, the response being dependent on macrophage activation.     

Kinetics of the biosynthesis of complement subcomponent C1q by murine macrophages: LPS, immune complexes, and zymosan alone and in combination with interferon-gamma.

We investigated the effects of bacterial lipopolysaccharide (LPS), immune complexes (IC), and C3b opsonized zymosan (AZ) alone and in combination with interferon-gamma (IFN-gamma) priming on macrophage synthesis and secretion of C1q. Our results indicated that LPS, IC, and AZ alone stimulated C1q mRNA and secretion in the absence of IFN-gamma. The increase in mRNA accumulation was detectable after 3 h, peaked at 6 h and was maintained at constitutive levels for 24 h. There was a corresponding early burst of increased secretion of functional C1q after 3 to 6 h which declined rapidly after 9 to 24 h culture of LPS-stimulated macrophages. Priming of macrophages with IFN-gamma and simultaneous triggering with LPS, IC, or AZ produced additive rather than synergistic increases in C1q mRNA accumulation. These same agents inhibited constitutive secretion of C1q in the absence of IFN-gamma priming as determined by autoradiographic analysis of metabolically radiolabeled secretory C1q. Triggering of IFN-gamma primed macrophages with LPS, IC, or AZ also markedly suppressed the increased rate of C1q secretion induced by IFN-gamma in a dose-related fashion. A corresponding dose-dependent increased accumulation of endogenous C1q in cell lysates was detected by Western blot analysis of macrophages which had been stimulated by LPS, IC, or AZ alone or in combination with IFN-gamma. Our findings indicate that LPS as well as FcR and C3bR triggering agents stimulate early and sustained C1q synthesis accompanied by an early and short-lived burst of C1q secretion which rapidly diminished and results in an increased intracellular accumulation of C1q due to ongoing synthesis. IFN-gamma appeared to further amplify the same kinetics of increased C1q mRNA accumulation and decreased extracellular accumulation mediated by LPS, IC, and ZM. Our results suggest that LPS, IC, and AZ alone or in combination with IFN-gamma stimulate early C1q production to modulate macrophage effector functions followed by an inhibition of C1q secretion when the activation process has been culminated.     

Markers of macrophage differentiation in experimental silicosis

Macrophages are characterized by a marked phenotypic heterogeneity depending on their microenvironmental stimulation. Beside classical activation (M1), it has been shown that macrophages could follow a different activation pathway after stimulation with interleukin (IL)-4 or IL-13 (M2). Recently, it has been postulated that those "alternatively activated" macrophages may be critical in the control of fibrogenesis. In an experimental model of silicosis, where pulmonary macrophages play a central role, we addressed the question of whether lung fibrosis development would be associated with alternative macrophage activation. As available markers for alternative macrophage activation, type-1 arginase (Arg-1), Fizz1, Ym1/2, and mannose receptor expression were evaluated at the mRNA and/or protein levels at different stages of the disease. Nitric oxide synthase-2 (NOS-2) expression was also examined to investigate the classical counterpart. We found that the expression of Arg-1, Fizz1, and NOS-2 in adherent bronchoalveolar lavage cells was highly up-regulated 3 days after silica administration but returned to control levels during the fibrotic stage of the disease (60 days). By comparing the early response to silica in C57BL/6 and BALB/c mice, we observed that the amplitude of Arg-1 mRNA up-regulation was not associated with the severity of lung fibrosis. Using a model of manganese dioxide particles (resolutive alveolitis), we showed that this early Arg-1 mRNA was not specific to a fibrogenic lung response. Our data indicate that the modifications of M1/M2 marker expression are limited to the early inflammatory stage of silicosis and that the establishment of a fibrotic process is not necessarily associated with M2 polarization.