Nitric oxide up-regulates the release of inflammatory mediators by mouse macrophages

Nitric oxide (NO) plays a key role in mediating macrophage cytotoxicity towards different targets, including tumoral cells and intracellular pathogens. However, its role in macrophage immunoregulation is less well defined. In this study, we have investigated the effect of altering NO levels on the production by mouse macrophages of cytokines, and reactive oxygen intermediates as measured by luminol-dependent chemiluminescence. Our results demonstrate that NO can enhance the release of both tumor necrosis factor-α and interleukin-1α, and chemiluminescence. Thus, in addition to acting as a powerful effector molecule in mediating cytotoxic activities of mouse macrophages, NO can play a role in enhancing the production of a variety of other inflammatory mediators, and thus can contribute both directly and indirectly to the immunopathology of macrophage-dependent inflammation.     

Effects of some antigenic fractions of Leishmania major on nitric oxide production and IL-12 secretion by murine peritoneal macrophages

Nitric oxide (NO) and IL-12 are important mediators of the immune response to Leishmania major. In this study, the effects of L. major promastigotes, crude antigenic fraction (CAF) and its subfractions on NO production and IL-12 secretion by BALB/c mice peritoneal macrophages is investigated. The subfractions of CAF, namely, fractions 1, 2 and 3, that were in the molecular weight range of 97.4–66, 66–45 and below 45 kDa, respectively, were separated by SDS-PAGE. NO production was determined by using Griess reagent and IL-12 was measured by ELISA. It was found that NO production was stimulated by promastigotes but not by CAF or its subfractions. IL-12 secretion was stimulated by promastigotes, CAF and fraction 1 while fractions 2 and 3 did not have any effect.     

Repeated induction of nitric oxide synthase and leishmanicidal activity in murine macrophages

Murine macrophages express high levels of nitric oxide (NO) synthase and produce large amounts of NO when stimulated with interferon-y plus lipopolysaccharide in vitro. The expression of NO synthase peaks at 12 h after stimulation and declines rapidly to the background level by 72 h. These macrophages can be repeatedly reactivated to express similar levels of NO synthase. The reactivation is not due to newly divided cells since peritoneal macrophages which do not divide in vitro and J774 cells cultured in the presence of colchicine can also be restimulated to express NO synthase. The reactivation is accompanied by re-expression of NO synthase mRNA, as assessed by polymerase chain reaction analysis. Furthermore, the reactivated macrophages are fully capable of killing the intracellular protozoan parasite Leishmania major.     

一氧化氮在实验性肝损伤中的作用

目的：观察３种细胞因子对体外培养大鼠肝细胞产生一氧化氮（ＮＯ）的影响及ＮＯ在实验性肝损伤中的作用。方法与结果：给大鼠注射内毒素后分离肝细胞,培养液中加入细胞因子（γ－ＩＦＮ,ＩＬ－２,ＴＮＦ－α）,上清液中ＮＯ含量增加,两种以上细胞因子联合应用,ＮＯ含量增加更明显;大鼠注射内毒素及Ｌ－精氨酸,血清中ＮＯ含量增加,肝损伤减轻;大鼠给硫代乙酰胺（ＴＡＡ）灌胃,并注射ＮＯ生成抑制剂Ｌ－ＮＮＡ,动物出现嗜     

Production of nitric oxide and superoxide by activated macrophages and killing of Leishmania major

Murine macrophages can be activated to produce nitric oxide (NO) and superoxide and these two radicals can react to form peroxynitrite, a powerful oxidant which may be involved in parasite killing. We now show that murine macrophages activated with zymosan and interferon-γ (ZYM/IFN-γ) produced both superoxide (peaking 1–2 h after stimulation, then rapidly declining) and NO (barely detectable at 6 h, peaking by 24 h). Macrophages activated with ZYM alone produced only superoxide, while stimulation with lipopolysaccharide (LPS) and IFN-γ induced NO but not superoxide. Cells stimulated with ZYM/IFN-γ or LPS/IFN-γ killed Leishmania major to a similar degree, an effect that was completely blocked by the addition of N-iminoethyl-L -ornithine. However, macrophages stimulated with ZYM alone were unable to kill L. major. S-nitroso-acetyl-penicillamine, which release NO, was highly leishmanicidal when added directly to the parasites. 3-morpholino-sydnonimine hydrochloride which releases both NO and superoxide simultaneously, was also efficient at killing L. major and this cytotoxicity was greatly enhanced by the addition of superoxide dismutase. Finally, authentic peroxynitrite failed to induce any cytotoxic effect, even at a high concentration. Thus macrophages can produce either NO, superoxide or both, depending on the stimulus. However, the killing of L. major is dependent only on the production of NO.     

糖基化终产物对巨噬细胞产生一氧化氮及其合酶活性的影响

目的:探讨糖基化终产物(AGEs)对巨噬细胞一氧化氮通路的影响及其机制。方法:应用一氧化氮(NO)及一氧化氮合酶(NOS)试剂盒测定巨噬细胞产生NO和NOS活性。结果:巨噬细胞产生NO含量及NOS活性随AGEs作用时间延长明显减少,并且随AGEs的浓度、糖化程度加重、葡萄糖修饰浓度增加,巨噬细胞产生NO含量及NOS活性呈减弱趋势,VitE明显增加巨噬细胞产生NO含量以及NOS活性。结论:AGEs通过抑制巨噬细胞NOS活性而抑制其产生NO,VitE对巨噬细胞具有保护作用,能减轻AGEs的损害作用,这对糖尿病慢性并发症的防治提供了重要的理论依据。     

Pre-exposure of murine macrophages to lipopolysaccharide inhibits the induction of nitric oxide synthase and reduces leishmanicidal activity

Murine macrophages produce nitric oxide (NO) from L-arginine on stimulation with lipopolysaccharide (LPS), alone or with interferon-γ (IFN-γ). The effect of incubation of macrophages with low concentrations of LPS on NO synthesis on subsequent stimulation was investigated, using a murine macrophage cell line, J774, and peritoneal macrophages from CBA mice. Cells which had been incubated with LPS produced significantly lower amounts of NO, and expressed lower levels of NO synthase activity, following stimulation with IFN-γ and LPS, or with a high concentration of LPS. This effect was not reversed by tumor necrosis factor-α. The ability of CBA macrophages to kill the intracellular parasite Leishmania major was markedly reduced by pre-incubation with LPS. Reduced NO production by macrophages previously exposed to LPS is a manifestation of endotoxin tolerance, and may represent an important means of regulation of NO synthesis and thus a survival mechanism for intracellular parasites.     

一氧化氮抑制剂对腹膜透析大鼠腹膜形态及表面层的影响

目的:探讨高糖透析液对大鼠腹膜巨噬细胞一氧化氮(NO)的产生、诱导型一氧化氮合酶(iNOS)的表达和腹膜透析通透性的影响以及NO抑制剂的保护作用。方法: 培养生理盐水、1.5％和4.25％葡萄糖透析液透析下的大鼠腹腔内的巨噬细胞, 检测细胞培养上清液NO的浓度和巨噬细胞iNOS的表达, 并观察1.5％及4.25％葡萄糖透析液和NO抑制剂透析下大鼠的液体超滤量和腹膜形态的变化。结果:大鼠腹腔内巨噬细胞NO的产生随透析液中葡萄糖含量增加而增加;腹腔巨噬细胞iNOS的表达, 葡萄糖透析组明显高于生理盐水组;NO抑制剂对光镜下腹膜形态无影响, 但明显减轻4.25%葡萄糖透析液对超滤量和腹膜表面层的减少作用。结论:一氧化氮抑制剂可明显改善高糖透析大鼠的腹膜通透性, 并减轻高糖对腹膜表面层的损伤。     

内皮型一氧化氮合酶基因转染对人吞噬细胞释放细胞因子和生成环核苷酸的影响

目的和方法:将内皮型一氧化氮合酶基因转染吞噬细胞,观察该基因表达对吞噬细胞释放细胞因子和cAMP的影响。 结果:内皮型一氧化氮合酶可在吞噬细胞获得稳定表达,但该产物在活细胞中不产生一氧化氮。一氧化氮合酶基因表达可上调TNF-α的释放,下调IL-10和cAMP的生成,使用一氧化氮合酶抑制剂不改变这种变化趋势。结论:内皮型一氧化氮合酶基因产物的功能具有细胞特异性。导致吞噬细胞功能变化的效应分子可能不是一氧化氮。     

Signaling events involved in cytokine and chemokine production induced by secretory phospholipase A2 in human lung macrophages

Secretory phospholipases A(2) (sPLA(2)) are enzymes released during inflammatory reactions. These molecules activate immune cells by mechanisms either related or unrelated to their enzymatic activity. We examined the signaling events activated by group IA (GIA) and group IB (GIB) sPLA(2) in human lung macrophages leading to cytokine/chemokine production. sPLA(2) induced the production of cytokines (TNF-alpha, IL-6 and IL-10) and chemokines (CCL2, CCL3, CCL4 and CXCL8), whereas no effect was observed on IL-12, CCL1, CCL5 and CCL22. sPLA(2) induced the phosphorylation of the MAPK p38 and ERK1/2, and inhibition of these kinases by SB203580 and PD98059, respectively, reduced TNF-alpha and CXCL8 release. Suppression of sPLA(2) enzymatic activity by a site-directed inhibitor influenced neither cytokine/chemokine production nor activation of MAPK, whereas alteration of sPLA(2) secondary structure suppressed both responses. GIA activated the phosphatidylinositol 3-kinase (PI3 K)/Akt system and a specific inhibitor of PI3 K (LY294002) reduced sPLA(2)-induced release of TNF-alpha and CXCL8. GIA promoted phosphorylation and degradation of IkappaB and inhibition of NF-kappaB by MG-132 and 6-amino-4-phenoxyphenylethylamino-quinazoline suppressed the production of TNF-alpha and CXCL8. These results indicate that sPLA(2) induce the production of cytokines and chemokines in human macrophages by a non-enzymatic mechanism involving the PI3 K/Akt system, the MAPK p38 and ERK1/2 and NF-kappaB.     

双歧杆菌的全肽聚糖对裸鼠腹腔巨噬细胞产生IL-6、IL-12及一氧化氮的影响

目的 :探讨分叉双歧杆菌 (B bifidum)的全肽聚糖对巨噬细胞功能的调节作用。方法 :首先用全肽聚糖注射于裸鼠腹腔 ,以ELISA法测定裸鼠腹腔巨噬细胞产生的IL - 6和IL - 12含量 ,同时用Griess试剂检测一氧化氮 (NO)的水平。结果 :全肽聚糖注射组裸鼠腹腔巨噬细胞产生的IL - 6、IL - 12及NO含量分别为732 5 4± 190 30 (pg/mL)、816 37± 96 40 (pg/mL)和 48 90± 6 5 1(μmol/L) ;对照组分别为 30 3 78± 171 75 (pg/mL)、5 10 2 7± 12 3 46 (pg/mL)以及 30 6 7± 12 83(μmol/L) ,三者比较均具有显著差异 (P <0 0 1)。 结论 :分叉双歧杆菌的全肽聚糖能激活巨噬细胞 ,使之分泌多量的IL - 6、IL - 12及NO ,这些细胞毒性效应分子介导了全肽聚糖的多种重要生理功能。     

一氧化氮/诱导型一氧化氮合酶在动脉粥样硬化过程中的作用

 目的：探讨一氧化氮（NO）/诱导型一氧化氮合酶（iNOS）在动脉粥样硬化（atherosclerosis,AS）过程中的动态变化,分析其对动脉粥样硬化形成过程的影响。方法：将60只SD大鼠随机分成2组：对照组及AS组,每组30只。AS组采用维生素D3腹腔注射联合高脂饲料饲养的方法构建动脉粥样硬化模型。用相关生化方法检测血清各项生化指标：总胆固醇、甘油三酯、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇、空腹血糖和钙离子,比色法检测血清NO浓度,并对主动脉行HE染色,免疫组化技术检测iNOS蛋白表达,将所得数据进行统计分析,用简单线性相关分析NO与钙离子及动脉粥样硬化指数的相关性。结果：90 d后成功构建了主动脉中膜钙化型动脉粥样硬化模型。血清NO浓度在动脉粥样硬化过程中逐步下降,各组间差异均有统计学意义（均P<0.05）。动脉粥样硬化过程中动脉粥样硬化指数与钙离子呈正相关,与NO呈负相关。在90 d的AS组粥样斑块区免疫组化技术检测到iNOS蛋白表达。结论:在动脉粥样硬化形成过程中,主动脉粥样斑块区iNOS蛋白高表达,但血清NO浓度逐渐降低,NO抗动脉粥样硬化作用减弱。     

Glycoinositolphospholipids of Leishmania major inhibit nitric oxide synthesis and reduce leishmanicidal activity in murine macrophages

Murine macrophages express high levels of inducible nitric oxide (NO) synthase and produce large amounts of nitric oxide when activated with interferon-γ and lipopolysaccharide in vitro. Nitric oxide is a mediator of a variety of biological functions including microbicidal activity against the protozoan parasite Leishmania species. Glycoinositolphospholipids (GIPL) are the predominant surface glycolipids in both developmental stages of Leishmania major. We report here that GIPL can inhibit the synthesis of NO in a time- and dose-dependent manner. In contrast, lipophosphoglycan, which is present in the promastigote stage did not inhibit NO synthesis. GIPL-treated macrophages also showed markedly reduced leishmanicidal activity. The majority of the inhibitory activity of GIPL was found within the alkylacylglycerol moiety of the GIPL molecule. These data, therefore, suggest that GIPL may contribute towards the survival of the parasite in the immune hosts.     

Leishmania major-specific CD8+ T cells are inducers and targets of nitric oxide produced by parasitized macrophages

Lines of Leishmania major-specific CD8⁺ T cells were derived from the lymph nodes and spleens of CBA mice, immune following resolution of a primary infection, 7 days after secondary challenge with viable L. major. Specific stimulation of these CD8⁺ T cells by bone marrow-derived macrophages infected with L. major led to the release of interferon-γ by CD8⁺ T cells and nitric oxide by macrophages. Interestingly, the nitric oxide released by bone marrow-derived macrophages down-regulated the production of interferon-γ by specifically activated CD8⁺ T cells. The proliferation and long-term maintenance of these parasite-specific CD8⁺ T cells was impaired by the nitric oxide produced by stimulating infected macrophages as a result of cytokines released by activated CD8⁺ T cells. Taken together, the results indicate that L. major-specific CD8⁺ T cells are sensitive to the toxic effect of the nitric oxide that they induce.     

一氧化氮合酶抑制剂对大鼠结肠炎损伤的影响

目的：了解一氧化氮合酶抑制剂L－精氨酸甲酯（L-NAME）对大鼠结肠炎损伤的影响。方法：将实验大鼠随机分为对照组、损伤组、NAME1、NAME2、NAME3（即N1、N2、N3）干预组。采用三硝基苯磺酸（TNB）30 mg+50%乙醇0.25 mL给大鼠灌肠复制结肠炎模型，并检测各组的溃疡指数（UI）、一氧化氮（NO）、MDA含量及GSH活性。结果：N1、N2、N3组的NO、UI、MDA值低于损伤组，GHS值高于损伤组，对照组的损伤不明显。相关分析表明，NO含量与MDA含量呈正相关，与GSH活性呈负相关。结论：在结肠炎症反应中，NO过量生成具有损伤作用，L－NAME通过抑制NOS活性，减少NO及自由基的生成，具一定的抗损伤作用。     

Csk overexpression reduces several monokines and nitric oxide productions but enhances prostaglandin E2 production in response to lipopolysaccharide in the macrophage cell line J774A.1

The catalytic activity of src-family protein tyrosine kinases (src-PTK) is suppressed when a C-terminal tyrosine is phosphorylated by an intracellular PTK, C-terminal Src kinase (Csk). In the present report, to study the regulatory functions of the Csk in cells of monocyte/macrophage lineage, we transfected a eukaryotic expression vector containing rat csk cDNA in a macrophage cell line, J774A.1, and examined alterations of the response to lipopolysaccharide (LPS) in the transfectants which overexpressed Csk. Csk overexpression resulted primarily in a down-regulation of Fgr activity, an src-PTK expressed in J774A.1, and hyperphosphorylation of several cellular proteins of 35, 57, 66, 97 and 120–130 kDa. Furthermore, in these Csk transfectants, production of interleukin (IL)-1α, IL-6, tumor necrosis factor-α, and nitric oxide (NO) following LPS stimulation were reduced compared with those in parental J774A.1 or J774A.1 transfected with the vector alone. The extent of reduction paralleled the amounts of Csk proteins expressed in the Csk-transfected J774A.1. The reduced NO production in these cells was associated with low levels of mRNA of inducible NO synthetase. On the other hand, an enhancement of prostaglandin E₂ production was observed in the Csk-transfected J774A.1 cells upon stimulation with LPS, which appeared to result from the high level of prostaglandin-H synthetase in the transfectants. The present findings indicate that overexpression of Csk has differential effects on the regulation of production of chemical mediators and monokines, probably via modulation of signal transduction downstream of LPS-mediated signals.     

Anti-inflammatory effect of Mentha longifolia in lipopolysaccharide-stimulated macrophages: Reduction of nitric oxide production through inhibition of inducible nitric oxide synthase

Abstract

Mentha longifolia is an aromatic plant used in flavoring and preserving foods and as an anti-inflammatory folk medicine remedy. The present study assessed the effects of M. longifolia extracts, including essential oil and crude methanol extract and its fractions (ethyl acetate, butanol and hexane), on nitric oxide (NO) production and inducible NO synthase (iNOS) mRNA expression in lipopolysaccharide (LPS)-stimulated J774A.1 cells using real-time polymerase chain reaction (PCR). The cytotoxic effects of the extracts on the cells were examined and non-cytotoxic concentrations (<0.2?mg/ml) were used to examine their effects on NO production and iNOS mRNA expression. Only the hexane fraction that contained high levels of phenolic and flavonoid compounds at concentrations from 0.05–0.20?mg/ml significantly reduced NO production in LPS-stimulated cells (p?<?0.001). Real-time PCR analysis indicated the ability of this fraction at the same concentrations to significantly decrease iNOS as well as TNFα mRNA expression in the cells (p?<?0.001). All extracts were able to scavenge NO radicals in a concentration-dependent manner. At concentrations greater than 0.2?mg/ml, total radicals were 100% scavenged. In conclusion, M. longifolia possibly reduces NO secretion in macrophages by scavenging NO and inhibiting iNOS mRNA expression, and also decreases TNFα pro-inflammatory cytokine expression, thus showing its usefulness in the inflammatory disease process.     

The effect of free gallium and gallium in liposomes on cytokine and nitric oxide secretion from macrophage-like cells in vitro

The aim of this study was to evaluate the effect of gallium nitrate, gallium-nitrilotriacetate (NTA) complex, and liposomal gallium-NTA on IL-6, TNF, and nitric oxide (NO) release from activated macrophages. In addition, the expression of the inducible nitric oxide synthase (iNOS) was determined. Gallium inhibited dose-dependently the secretion of IL-6, TNF, and NO from the LPS-induced macrophage-like RAW 264 cells. Encapsulation of gallium in negatively charged DSPG-liposomes increased its potency 10–50 times and 7–11 times compared to free gallium nitrate and gallium-NTA, respectively. Neither non-loaded liposomes nor NTA alone inhibited cytokine or NO secretion, demonstrating that the observed effects originated from gallium. Liposomal gallium-NTA inhibited the expression of iNOS by the macrophages, while other formulations of gallium had no effect. Thus, gallium, when delivered properly, suppresses macrophage functions by inhibiting the release of inflammatory mediators from the cells.