Macrophage migration inhibitory factor induces phagocytosis of foreign particles by macrophages in autocrine and paracrine fashion.

Exposure to foreign particles sometimes causes inflammatory reactions through production of cytokines and chemoattractants by phagocytic cells. In this study, we focused on macrophage migration inhibitory factor (MIF) to evaluate its pathophysiological role in the phagocytic process. Immunohistochemical analysis of human pseudosynovial tissues retrieved at revision of total hip arthroplasty showed that infiltrating mononuclear and multinuclear cells were positively stained by both an anti-CD68 antibody and anti-human MIF antibody. For in vitro study, MIF was released from murine macrophage-like cells (RAW 264.7) in response to phagocytosis of fluorescent-latex beads in a particle dose-dependent manner. Northern blot analysis showed marked elevation of the MIF mRNA level in the phagocytic macrophage-like cells. Moreover, pretreatment of RAW 264.7 cells with rat recombinant MIF increased the extent of phagocytosis by 1.6-fold compared with the control. Taken together, these results suggest that MIF plays an important role by activating macrophages in autocrine and paracrine fashion to phagocytose foreign particles.     

Macrophage migration inhibitory factor expression in male and female ethanol-fed rats.

Macrophage migration inhibitory factory (MIF) regulates macrophage accumulation at sites of injury and can promote the inflammatory response. We studied MIF expression in the intragastric feeding rat model for alcoholic liver injury. Male and age-matched female rats were fed ethanol or dextrose with fish oil. Two groups of male rats were fed medium-chain triglycerides with ethanol or dextrose. Analysis of liver histopathology, lipid peroxidation, endotoxin, mRNA, and immunohistochemistry for MIF, tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) were carried out. Male and female rats fed fish oil and ethanol showed necroinflammatory liver injury and had the highest expression of MIF, TNF-alpha, and IFN-gamma in the liver. Decreased levels of MIF protein were seen in rats with higher endotoxin levels, suggesting that preformed MIF is released into the circulation. MIF is an important mediator of the inflammatory response in alcoholic liver disease and a potential therapeutic target.     

Macrophage migration inhibitory factor has a proinflammatory activity via the p38 pathway in glucocorticoid-resistant ulcerative colitis

Macrophage migration inhibitory factor (MIF) is a cytokine that has potent anti-steroid effects and might be implicated in the pathogenesis of Ulecrative colitis (UC). We defined the functional role of MIF in the glucocorticoid (GC)-resistant inflammatory response in UC. Twenty-four colonic samples were obtained from GC responsive cases, GC refractory cases, Crohn's disease and controls. LPMC were isolated from surgical specimens. MIF was strongly expressed at mRNA levels in refractory cases rather than responsive cases with UC and controls. IL-8 production from LPMC was significantly reduced by GC addition in responsive cases but not in refractory cases. In refractory cases, anti-MIF Ab ameliorated GC-resistant IL-8 production and p38-MAPK activity of LPMC. In addition, p38-MAPK antagonist SB230580 also ameliorated GC-resistant IL-8 production. These results suggest that MIF has an additional proinflammatory activity through the p38-MAPK pathway in GC-resistant UC.     

Macrophage migration inhibitory factor reduces the growth of virulent Mycobacterium tuberculosis in human macrophages

Macrophage migration inhibitory factor (MIF) is a key mediator of the innate immune system and plays a crucial role in the host response to bacterial infections. Its role in immunity to intracellular pathogens has not been well studied. Here, we show that MIF released by infected human macrophages inhibits the growth of virulent Mycobacterium tuberculosis.     

Macrophage migration inhibitory factor induces cell death and decreases neuronal nitric oxide expression in spinal cord neurons

Macrophage migration inhibitory factor is a potent proinflammatory cytokine; however, its role in spinal cord injury is poorly understood. Therefore, the aim of the present study was to investigate the effects of macrophage migration inhibitory factor on spinal cord neuron survival and viability. Due to the importance of nitric oxide metabolism in these events, part of our study was also focused on the influence of recombinant macrophage migration inhibitory factor on neuronal nitric oxide expression. Exposure of cultured mouse spinal cord neurons to macrophage migration inhibitory factor markedly increased cellular oxidative stress as measured by 2',7'-dichlorofluorescein fluorescence and intracellular calcium levels. In addition, an antagonist of the inositol 1,4,5-triphosphate receptor, 8-(diethylamino)octyl 3,4,5-trimethoxybenzoate, completely blocked the macrophage migration inhibitory factor-induced increase in intracellular calcium levels. Macrophage migration inhibitory factor treatment also decreased cell viability, increased cellular lactate dehydrogenase release, and induced chromatin condensation and aggregation in cultured spinal cord neurons. Finally, exposure to macrophage migration inhibitory factor markedly decreased expression and activity of neuronal nitric oxide, accompanied by a decrease in cellular guanosine 3'5'-cyclic monophosphate levels. The present results indicate that macrophage migration inhibitory factor can induce dysfunction of spinal cord neurons, leading to cell death through oxidative stress and intracellular calcium-dependent pathways.     

鼻咽癌组织中巨噬细胞移动抑制因子和MMP-2、MMP-9表达的关系

目的　研究巨噬细胞移动抑制因子 (macrophagemigrationinhibitoryfactor,MIF)和MMP 2、MMP 9在鼻咽癌组织中的表达水平及相互关系 ,探讨鼻咽癌细胞早期侵袭转移的机制。方法　收集 4 5例确诊的鼻咽原发癌活检组织标本 ,采用免疫组化LSAB法检测鼻咽癌组织中MIF和MMP 2、MMP 9的表达 ,并分析患者的临床参数的关系。结果　在 4 5例鼻咽原发癌组织中 ,MIF、MMP 2和MMP 9的阳性表达率分别为 77 8% (35 / 4 5 )、6 4 4 % (2 9/ 4 5 )和 71 1% (32 / 4 5 )。其中 ,癌细胞MIF和MMP 9的表达水平均显示与淋巴结转移有关 ,伴有淋巴结转移的癌组织中二者表达水平均高于无淋巴结转移的癌组织 (P值均 <0 0 5 )。MIF阳性组的癌细胞MMP 9的表达 (5 0 2 %± 33 5 % )明显高于MIF阴性病例 (11 7%± 2 2 7% ) ,两者差异有显著性 (P <0 0 1) ,且MIF的表达与MMP 9的表达亦呈正相关 (rs=0 .4 92 ,P <0 0 1) ,但癌细胞MMP 2的表达与MIF、MMP 9的表达以及是否有淋巴结转移则均未显示相关性。以Schmincke型生长方式分布的癌细胞MIF表达水平 (6 7 4 %±35 2 % )也高于以Regaud型方式分布的癌细胞 (32 9%± 2 9 7% ) ,差异有显著性 (P <0 0 1)。结论　鼻咽癌组织中癌细胞的MIF和MMP 9同步过表达 ,可能在鼻咽癌细胞的转移     

Nerve growth factor regulates TNF-alpha production in mouse macrophages via MAP kinase activation

In this study, we examined the expression of nerve growth factor (NGF) and its receptors in mouse macrophages and the mechanisms involved in the effect of NGF on tumor necrosis factor (TNF)-alpha production. Macrophages expressed NGF and the NGF receptors TrkA and p75. Treatment of J744 cells or peritoneal macrophages with NGF induced a large increase in the production of TNF-alpha. In addition, NGF induced the secretion of nitric oxide in interferon-gamma-treated J774 cells or lipopolysaccharide-treated peritoneal macrophages. The induction of TNF-alpha production by NGF was blocked by K252a, an inhibitor of the TrkA receptor. NGF induced phosphorylation and activation of extracellular signal-regulated kinase, Erk1/Erk2 and c-Jun amino-terminal kinase, whereas it did not induce phosphorylation of p38 mitogen-activated protein kinase. Inhibition of the MAP kinase-Erk kinase pathway with PD 098059 decreased the secretion of TNF-alpha by NGF. Our results suggest that NGF has an important role in the activation of macrophages during inflammatory responses via activation of mitogen-activated protein kinases.     

Macrophage migration inhibitory factor activates antigen-presenting dendritic cells and induces inflammatory cytokines in ulcerative colitis

The level of macrophage migration inhibitory factor (MIF) and the functions of dendritic cells (DC) are up-regulated in the peripheral blood, and the numbers of MIF-expressing cells and mature DC are increased at the colonic mucosa from patients with ulcerative colitis (UC). However, a functional relationship between MIF and DC, and the role of MIF in the pathogenesis of UC, are not clear. In this study, we showed that a pure population of peripheral blood DC is a new and still unknown source of MIF. DC from UC patients produced significantly higher levels of MIF (17 x 5 +/- 9 x 8 ng/ml, n = 10) compared with patients with Crohns disease (CD) (4 x 6 +/- 2 x 5 ng/ml, n = 5, P< 0 x 01) and control subjects (5 x 0 +/- 2 x 6 ng/ml, n = 10, P< 0 x 01). A double immunofluorescence study revealed the expression of MIF by CD83-positive mature DC at the colonic mucosa from UC patients. Blood DC treated with high amounts of MIF (500 ng/ml) showed a significantly higher stimulatory capacity (43287 +/- 5998 CPM, n = 5) in an allogenic mixed leucocyte reaction compared with untreated DC (27528 +/- 8823 CPM, n = 5, P< 0 x 05). Study of intracellular cytokine expression showed that MIF induced significant levels of interleukin (IL)-1 and IL-8 in monocytes and DC from UC and CD patients. These results showing the capacity of MIF to induce increased functional capacity of DC, and to produce IL-1 and IL-8 from monocytes and DC, indicate a role of MIF in the induction and/or perpetuation of the inflammatory environment in UC.     

Macrophage migration inhibitory factor promotes innate immune responses by suppressing glucocorticoid-induced expression of mitogen-activated protein kinase phosphatase-1

The pro-inflammatory cytokine macrophage migration inhibitory factor (MIF) acts as a physiological counter-regulator of the immuno-suppressive effects of glucocorticoids. However, the mechanisms whereby MIF exerts its counter-balancing effect remain largely unknown. Here we report that MAPK phosphatase 1 (MKP-1), an archetypal member of dual specificity phosphatase that inactivates MAPK activity in response to pro-inflammatory stimuli, is a critical target of MIF-glucocorticoid crosstalk. Recombinant MIF counter-regulated in a dose-dependent fashion dexamethasone inhibition of TNF and IL-8 production by RAW 264.7 macrophages and U-937 promonocytes stimulated with lipopolysaccharides (LPS) or with LPS plus phorbol 12-myristate 13-acetate. Stimulation of RAW 264.7 macrophages with dexamethasone or dexamethasone plus LPS led to a robust up-regulation of MKP-1 mRNA and protein expressions that were counter-regulated by addition of recombinant MIF. Antisense MIF macrophages expressing reduced levels of endogenous MIF produced higher amount of MKP-1 and lower amount of TNF after exposure to dexamethasone and dexamethasone plus LPS, indicating that endogenous MIF acts in an autocrine fashion to override glucocorticoid-induced MKP-1 expression and inhibition of cytokine production. Taken together, these data identify MKP-1 as a molecular target of MIF-glucocorticoid crosstalk and provide a molecular basis for the control of macrophage responses by a pair of physiological regulators of innate immunity.     

Macrophage migration inhibitory factor in human pregnancy and labor

PROBLEM: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine involved in reproduction. Presently there is no information on the possible involvement of MIF in the onset of labor. METHODS: Macrophage migration inhibitory factor was assayed, by enzyme-linked immunosorbent assay (ELISA), in maternal serum (MS) and amniotic fluid (AF) both, at midtrimester and at term, as well as in cord serum (CS) at birth. Extraembryonic membranes were analyzed by immunohistochemistry. RESULTS: Amniotic fluid MIF concentrations were significantly higher at term (median 62.10 ng/mL) than at midtrimester (median 20.07 ng/mL) and reached a peak in term labor (median 258.80 ng/mL). The AF/MS ratio varied from a median of 4.34 at midtrimester and 33.7 at term labor. The MS/CS ratio was 0.4. Migration inhibitory factor immunoreactivity was found in different cell layers of the extraembryonic membranes. CONCLUSIONS: The increased secretion of MIF in AF at term, particularly at term labor, suggests that MIF contributes to the inflammatory events leading to labor.     

氧化型低密度脂蛋白诱导巨噬细胞移动抑制因子的表达

目的:探讨氧化型低密度脂蛋白(ox-LDL)对人巨噬细胞分泌巨噬细胞移动抑制因子(MIF)的影响。方法:体外培养巨噬细胞株28SC,在其培养基中加入终浓度为150mg/L的氧化型低密度脂蛋白进行时间效应实验,37℃共育后,分别于0h、3h、6h、12h、24h、36h收集细胞和培养介质;在其培养基中分别加入终浓度为0mg/L、15mg/L、30mg/L、75mg/L、150mg/L、300mg/L的氧化型低密度脂蛋白进行剂量效应实验,37℃共育24h后收集细胞和培养介质。采用RT-PCR和ELISA分别测定MIFmRNA和蛋白表达水平。结果:氧化型低密度脂蛋白可诱导培养巨噬细胞分泌MIFmRNA和蛋白,并呈时间和剂量依赖性增加。结论:MIF可能参与氧化型低密度脂蛋白所致的动脉粥样硬化进程。     

Macrophage migration inhibitory factor and its role in autoimmune diseases

After several decades of research into the macrophage migration inhibitory factor (MIF), its diverse actions in the immune system are yet to be fully revealed. What has become clear is that MIF plays an important role in both innate and adaptive immunity. However, while several pathways mediating the function of MIF in the immune system have been established, its role in pathogenic states such as autoimmune diseases has remained unresolved. MIF has been implicated in different autoimmune diseases, including rheumatoid arthritis, glomerulonephritis, and multiple sclerosis, but knowledge about the underlying cellular and molecular mechanisms is just emerging. However, overall it appears that the inhibition of its proinflammatory action is likely to be a successful new therapeutic strategy for some autoimmune diseases, possibly by reducing the need for steroids. As more aspects of the role of this cytokine in the pathogenesis of autoimmune diseases are elucidated, better strategies to target it therapeutically can be expected.     

Macrophage migration inhibitory factor (MIF) in bronchial asthma

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine favouring the secretion of TNFalpha and IL-8 and counteracts anti-inflammatory effects of corticosteroids. Airways inflammation is a central feature of bronchial asthma and is characterized by the accumulation of eosinophils. OBJECTIVE: The aim of this study was to investigate whether MIF is related to asthma symptoms and eosinophil accumulation in the airways. METHODS: Serum MIF levels were measured by an enzyme-linked immunosorbent assay in 44 healthy subjects and 44 asthmatics. Levels of MIF in induced sputum were measured in 10 healthy subjects and 15 asthmatics. Levels of eosinophil cationic protein (ECP) in induced sputum were measured by a radioimmunosorbent assay. Fluorescence double immunostaining was conducted to examine cellular source and localization of MIF. RESULTS: Serum MIF levels were significantly increased in asthmatic patients compared with age and sex-matched control subjects. Symptomatic patients had a higher MIF level than asymptomatic patients. Induced sputum obtained from asthmatics contained higher levels of MIF than those from control subjects. MIF levels in induced sputum were correlated with ECP levels in induced sputum. MIF was colocalized with eosinophil peroxidase staining in the cytoplasm of sputum cells. CONCLUSION: Increased MIF levels are associated with asthma symptoms and one of the cellular sources of MIF in the airways are eosinophils.     

Macrophage migration inhibitory factor in acute lung injury: expression, biomarker, and associations

The macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine central to the response to endotoxemia, is a putative biomarker in acute lung injury (ALI). To explore MIF as a molecular target and candidate gene in ALI, the MIF gene and protein expression were examined in murine and canine models of ALI (high tidal volume mechanical ventilation, endotoxin exposure) and in patients with either sepsis or sepsis-induced ALI. MIF gene expression and protein levels were significantly increased in each ALI model, with serum MIF levels significantly higher in patients with either sepsis or ALI compared with healthy controls (African- and European-descent). The association of 8 MIF gene polymorphisms (single-nucleotide polymorphisms (SNPs)) (within a 9.7-kb interval on chromosome 22q11.23) with the development of sepsis and ALI in European-descent and African-descent populations was studied next. Genotyping in 506 DNA samples (sepsis patients, sepsis-associated ALI patients, and healthy controls) revealed haplotypes located in the 3' end of the MIF gene, but not individual SNPs, associated with sepsis and ALI in both populations. These data, generated via functional genomic and genetic approaches, suggest that MIF is a relevant molecular target in ALI.     

表达载体介导的反义RNA抑制人巨噬细胞移动抑制因子的表达

目的：研究表达载体介导的反义RNA对人巨噬细胞移动抑制因子(MIF)表达的抑制作用。 方法:用亚克隆技术构建可转录MIF反义RNA的真核表达载体pcDNA3-antiMIF。用lipofectamine2000分别将pcDNA3、pcDNA3-antiMIF转染可表达MIF的HEK293(293-MIF)细胞，用Real-time定量PCR鉴定MIF mRNA表达水平。将pcDNA3-antiMIF转化人脐静脉血管内皮细胞(HUVECs)，建立可表达MIF反义RNA的HUVECs(HUVECs-antiMIF)细胞。将MIF的真核表达载体pSecTag-MIF转染HUVECs-antiMIF，用Real-time定量PCR鉴定MIF mRNA的表达水平。 结果:正确构建了MIF反义RNA的表达载体pcDNA3-antiMIF。MIF 反义RNA对293-MIF细胞中MIF表达的抑制水平达32%（P<0.05）。建立稳定表达MIF反义RNA的HUVECs-antiMIF细胞株。HUVECs-antiMIF中MIF的表达受到抑制，表达水平降低40%（P<0.05）。 结论:表达载体介导的反义RNA能有效地抑制MIF的表达，建立了稳定表达MIF反义RNA的HUVECs。     

Effects of antisense oligonucleotides on theexpression of macrophage migration inhibitoryfactor on macrophages

It is well known that the infiltration and prolifera tion of macrophages are the main features in manycases of experimental studies and human glomeru lonephritis, and they also play an important role inthe progressive renal injuries in the development ofglonerulonephritis [ 1 4 ]. Macrophage migrationfactor (MIF) is a proinflammatory cytokine thatwas originally described as a product of activatedlymphocytes that inhibited the random migration ofmacrophages in vitro and promoted the acc…     

Macrophage migration inhibitory factor counter‐regulates dexamethasone‐induced annexin 1 expression and influences the release of eicosanoids in murine macrophages

Macrophage migration inhibitory factor (MIF), a pro‐inflammatory cytokine and glucocorticoid (GC) counter‐regulator, has emerged as an important modulator of inflammatory responses. However, the molecular mechanisms of MIF counter‐regulation of GC still remain incomplete. In the present study, we investigated whether MIF mediated the counter‐regulation of the anti‐inflammatory effect of GC by affecting annexin 1 in RAW 264.7 macrophages. We found that stimulation of RAW 264.7 macrophages with lipopolysaccharide (LPS) resulted in down‐regulation of annexin 1, while GC dexamethasone (Dex) or Dex plus LPS led to significant up‐regulation of annexin 1 expression. RNA interference‐mediated knockdown of intracellular MIF increased annexin 1 expression with or without incubation of Dex, whereas Dex‐induced annexin 1 expression was counter‐regulated by the exogenous application of recombinant MIF. Moreover, recombinant MIF counter‐regulated, in a dose‐dependent manner, inhibition of cytosolic phospholipase A2α (cPLA2α) activation and prostaglandin E₂ (PGE₂) and leukotriene B₄ (LTB₄) release by Dex in RAW 264.7 macrophages stimulated with LPS. Endogenous depletion of MIF enhanced the effects of Dex, reflected by further decease of cPLA2α expression and lower PGE₂ and LTB₄ release in RAW 264.7 macrophages. Based on these data, we suggest that MIF counter‐regulates Dex‐induced annexin 1 expression, further influencing the activation of cPLA2α and the release of eicosanoids. These findings will add new insights into the mechanisms of MIF counter‐regulation of GC.