Gene polymorphisms of macrophage migration inhibitory factor affect susceptibility to chronic hepatitis B virus infection in an Iranian cohort

Macrophage migration inhibitory factor (MIF), a key proinflammatory mediator, plays important roles in chronic diseases. In this study, an attempt was made to clarify the associations between some functional polymorphisms such as MIF‐173 G/C, MIF 95 bp and 189 bp insertion/deletion (I/D) polymorphisms and chronic hepatitis B virus (HBV) infection. Polymorphisms were assessed in 221 HBV patients and 200 normal subjects. MIF‐173 G/C and MIF 95 bp and 189 bp I/D polymorphisms were genotyped using PCR–RFLP and PCR, respectively. When allele and genotype frequencies of the variants were compared between patients and controls by the χ² test, it was found that the frequency of MIF‐173 G/C genotypes differed significantly between patients with chronic HBV and healthy controls (P < 0.05). Carriers of the MIF ‐173‐C allele were at significantly higher risk of HBV infection than carriers of the MIF ‐173‐G allele (P = 0.009, OR = 1.549, 95% CI = 1.114 ? 2.155). Moreover, 95 bp I/D polymorphism was not associated with CP and the 185 bp I/D variant was not polymorphic in our group of subjects. The frequency of haplotypes did not differ significantly between groups (χ² = 11.391, P = 0.181). Our results suggest that MIF ‐173 G/C variant increases the risk of HBV in Iranian subjects. Further studies with larger sample sizes and different ethnicities are required to validate our findings.

     

Antisense macrophage migration inhibitory factor (MIF) prevents anti-IgM mediated growth arrest and apoptosis of a murine B cell line by regulating cell cycle progression

Macrophage migration inhibitory factor (MIF) is involved in the generation of cell-mediated immune responses. Recently it has been reported that MIF also plays a role in cell proliferation and differentiation. In the present study, using a B-cell line, WEHI-231, and its stable MIF-antisense transfectant, WaM2, as a representative transfectant, we investigated the mechanism underlying regulation of the cell growth by MIF. WaM2 cells produced less MIF than vector control or parental WEHI-231 cells. Reduced and increased proportions were seen in G1 and S-phase cells, respectively, in WaM2 as compared with WEHI-231. Growth arrest and apoptosis after stimulation via surface Ig (sIg) were less prominent in WaM2 cells than those in WEHI-231. However, the addition of recombinant rat MIF did not reverse the inhibition of the growth arrest and apoptosis induced in WaM2 by cross-linking sIg. Almost the same amount of p27kip1 expression was detected in WaM2 cells as those in WEHI-231 and vector control cells. Cross-linking of sIg elevated the p27kip1 level equally in these cells irrespective of the MIF-antisense expression. Taken together, it seems that MIF plays a role in inducing apoptosis in B cells upon IgM cross-linking by regulating the cell cycle via a novel intracellular pathway.     

胰腺癌组织中巨噬细胞移动抑制因子的表达及其意义

目的研究巨噬细胞移动抑制因子（MIF）在胰腺癌发生发展中的作用,与肿瘤标志物CEA、CA199的关系。方法应用免疫组化方法检测31例胰腺癌组织、癌旁组织以及14例正常胰腺组织中MIF表达水平,分析MIF表达与各项临床病理特点及血清CEA、CA199水平的关系。结果 MIF在胰腺癌组织中的表达为87.1%,高于癌旁组织的54.8%和正常胰腺组织的7.4%（P〈0.01）;癌旁组织的MIF表达高于正常组织（P〈0.01）。MIF的表达与肿瘤分化程度及远处转移有关（P〈0.05）,MIF表达阳性患者的血清CA199水平高于MIF表达阴性患者,而血清CEA水平两组间无显著统计学意义。结论 MIF对胰腺癌的发生发展起重要作用,可能促进正常腺体组织向胰腺癌发生和发展。MIF可作为胰腺癌的一种血清标志物,联合CA199的检测可更好的发现胰腺癌。     

Association of macrophage migration inhibitory factor (MIF) polymorphisms with risk of meningitis from Streptococcus pneumoniae

Macrophage migration inhibitory factor (MIF) is an upstream proinflammatory cytokine encoded by a functionally polymorphic locus. This study of 119 patients explored the potential relationship between MIF genotype and invasive Streptococcus pneumoniae infections. We observed an association between a high-expression MIF allele and occurrence of pneumococcal meningitis.     

Macrophage migration inhibitory factor (MIF) promotes rat airway muscle cell proliferation and migration mediated by ERK1/2 and FAK signaling

Macrophage migration inhibitory factor (MIF) is an inflammatory mediator that contributes to asthmatic airway remodeling; however, little is known regarding the effects of MIF on airway smooth muscle cells (ASMCs). In the present study, we found that an enhanced expression of MIF promoted ASMC proliferation, increased the population of cells in the S/G2 phase, downregulated P21 expression, and upregulated cyclin D1, cyclin D3, and Cdk6 expression. In addition, the apoptosis of ASMCs was significantly decreased in response to MIF overexpression, compared with the negative control. Moreover, MIF facilitated the migration of ASMCs by upregulating the expression of matrix metalloproteinase (MMP)‐2. Finally, we showed that MIF increased the phosphorylation of extracellular regulated protein kinases (ERK) 1/2 and focal adhesion kinase (FAK), which are associated with proliferation and migration. In conclusion, this study demonstrated that MIF overexpression promotes the proliferation and migration of ASMCs by upregulating the activity of the ERK1/2 and FAK signaling pathways in these cells, further indicating that inhibition of MIF may prove to be an effective strategy for treating asthma patients with airway remodeling.     

Macrophage migration inhibitory factor (MIF) promotes fibroblast migration in scratch-wounded monolayers in vitro

MIF was recently redefined as an inflammatory cytokine, which functions as a critical mediator of diseases such as septic shock, rheumatoid arthritis, atherosclerosis, and cancer. MIF also regulates wound healing processes. Given that fibroblast migration is a central event in wound healing and that MIF was recently demonstrated to promote leukocyte migration through an interaction with G-protein-coupled receptors, we investigated the effect of MIF on fibroblast migration in wounded monolayers in vitro. Transient but not permanent exposure of primary mouse or human fibroblasts with MIF significantly promoted wound closure, a response that encompassed both a proliferative and a pro-migratory component. Importantly, MIF-induced fibroblast activation was accompanied by an induction of calcium signalling, whereas chronic exposure with MIF down-regulated the calcium transient, suggesting receptor desensitization as the underlying mechanism.     

Specific reduction of insulin disulfides by macrophage migration inhibitory factor (MIF) with glutathione and dihydrolipoamide: potential role in cellular redox processes

The molecular mechanism of action of MIF, a cytokine that plays a critical role in the host immune and inflammatory response, has not yet been identified. We recently demonstrated that MIF is an enzyme that exhibits oxidoreductase activity by a cysteine thiol-mediated mechanism. Here we further investigated this function by examining the reduction of insulin disulfides by wild-type human MIF (wtMIF) using various substrates, namely glutathione (GSH), dihydrolipoamide, l-cysteine, β-mercaptoethanol and dithiothreitol. The activity of wtMIF was compared to that of the relevant cysteine mutants of MIF and to two carboxy-truncated mutants. Only GSH and dihydrolipoamide were found to serve as reductants, whereas the other substrates were not utilized by MIF. Reduction of insulin disulfides by MIF was closely dependent on the presence of the Cys⁵⁷-Ala-Leu-Cys⁶⁰ (CALC) motif-forming cysteines C57 and C60, whereas C81 was not involved (activities: 51±13%, 14±5%, and 70±12% of wtMIF, respectively, and 20±3% for the double mutant C57S/C60S). Confirming the notion that the activity of MIF was dependent on the CALC motif in the central region of the MIF sequence, the C-terminal deletion mutants MIF(1–105) and MIF(1–110) were found to be fully active. The favored use of GSH and dihydrolipoamide indicated that MIF may be involved in the regulation of cellular redox processes and was supported further by the finding that MIF expression by the cell lines COS-1 and RAW 264.7 was significantly induced upon treatment with the oxidant hydrogen peroxide.     

Dual regulation of macrophage migration inhibitory factor (MIF) expression in hypoxia by CREB and HIF-1

Macrophage migration inhibitory factor (MIF) is a well-described pro-inflammatory mediator that has also been implicated in the process of oncogenic transformation and tumor progression. However, despite the compelling evidence that MIF is overexpressed in, and contributes to, the pathology of inflammatory and malignant diseases the mechanisms that contribute to exaggerated expression of MIF have been poorly described. Here we show that hypoxia, and specifically HIF-1alpha, is a potent and rapid inducer of MIF expression. In addition, we demonstrate that hypoxia-induced MIF expression is dependent upon a HRE in the 5'UTR of the MIF gene but is further modulated by CREB expression. We propose a model where hypoxia-induced MIF expression is driven by HIF-1 but amplified by hypoxia-induced degradation of CREB. Given the importance of MIF in inflammatory and malignant diseases these data reveal a HIF-1-mediated pathway as a potential therapeutic target for suppression of MIF expression in hypoxic tissues.     

Blockage of macrophage migration inhibitory factor (MIF) suppressed uric acid-induced vascular inflammation,smooth muscle cell de-differentiation,and remodeling

Hyperuricemia contributes to vascular injury and dysfunction, yet the potential mechanisms are not well understood. Uric acid (UA) has been found to stimulate macrophage migration inhibitory factor (MIF) up-regulation in renal tubules from rats subjected to UA-induced nephropathy. Given that MIF is able to induce vascular smooth muscle cell (VSMC) de-differentiation (from contractile state to a secretory state), we thus hypothesized that UA-induced vascular injury is via up-regulating of MIF in VSMCs, which enhancing vascular inflammation and VSMC transition. Within a mouse model of UA injection (500?mg/kg, twice/day, 14 days), we measured circulating and vascular MIF levels under UA stimulation at 6?h, day 1, and 14. We tested the efficacy of MIF inhibitor (10?mg/kg, twice/day, 14 days) on UA-induced vascular inflammation and remodeling. High plasma level of UA induced vascular MIF release into the plasma at acute phase. In the chronic phase, the protein level of MIF is up-regulated in the vessels. MIF inhibitor suppressed vascular inflammatory responses, repressed VSMC de-differentiation, and attenuated vascular remodeling and dysfunction following UA stimulation. Knockdown of MIF in cultured VSMCs repressed UA-induced de-differentiation. Our results provided a novel mechanism for MIF-mediated vascular injury in response to UA stimulation, and suggested that anti-MIF interventions may be of therapeutic value in hyperuricemic patients.     

The crystal structures of macrophage migration inhibitory factor from Plasmodium falciparum and Plasmodium berghei

Malaria, caused by Plasmodium falciparum and related parasites, is responsible for millions of deaths each year, mainly from complications arising from the blood stages of its life cycle. Macrophage migration inhibitory factor (MIF), a protein expressed by the parasite during these stages, has been characterized in mammals as a cytokine involved in a broad spectrum of immune responses. It also possesses two catalytic activities, a tautomerase and an oxidoreductase, though the physiological significance of neither reaction is known. Here, we have determined the crystal structure of MIF from two malaria parasites, Plasmodium falciparum and Plasmodium berghei at 2.2 Å and 1.8 Å, respectively. The structures have an α/β fold and each reveals a trimer, in agreement with the results of analytical ultracentrifugation. We observed open and closed active sites, these being distinguished by movements of proline‐1, the catalytic base in the tautomerase reaction. These states correlate with the covalent modification of cysteine 2 to form a mercaptoethanol adduct, an observation confirmed by mass spectrometry. The Plasmodium MIFs have a different pattern of conserved cysteine residues to the mammalian MIFs and the side chain of Cys58, which is implicated in the oxidoreductase activity, is buried. This observation and the evident redox reactivity of Cys2 suggest quite different oxidoreductase characteristics. Finally, we show in pull‐down assays that Plasmodium MIF binds to the cell surface receptor CD74, a known mammalian MIF receptor implying that parasite MIF has the ability to interfere with, or modulate, host MIF activity through a competitive binding mechanism.     

Macrophage migration inhibitory factor (MIF): a key player in protozoan infections

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine produced by the pituitary gland and multiple cell types, including macrophages (Mø), dendritic cells (DC) and T-cells. Upon releases MIF modulates the expression of several inflammatory molecules, such as TNF-α, nitric oxide and cyclooxygenase 2 (COX-2). These important MIF characteristics have prompted investigators to study its role in parasite infections. Several reports have demonstrated that MIF plays either a protective or deleterious role in the immune response to different pathogens. Here, we review the role of MIF in the host defense response to some important protozoan infections.     

Association between high expression macrophage migration inhibitory factor (MIF) alleles and West Nile virus encephalitis

Infection with mosquito-borne West Nile virus (WNV) is usually asymptomatic but can lead to severe WNV encephalitis. The innate cytokine, macrophage migration inhibitory factor (MIF), is elevated in patients with WNV encephalitis and promotes viral neuroinvasion and mortality in animal models. In a case-control study, we examined functional polymorphisms in the MIF locus in a cohort of 454 North American patients with neuroinvasive WNV disease and found patients homozygous for high-expression MIF alleles to be >20-fold (p = 0.008) more likely to have WNV encephalitis. These data indicate that MIF is an important determinant of severity of WNV neuropathogenesis and may be a therapeutic target.     

Early release of macrophage migration inhibitory factor after liver ischemia and reperfusion injury in rats

Macrophage migration inhibitory factor (MIF) is an important mediator of ischemia/reperfusion (I/R) injury in heart, brain and intestine. We previously demonstrated that MIF was released during warm/cold ischemia in vitro. However, the role of MIF in liver I/R injury remains unclear. We aimed to test the hypothesis that MIF acts as an early proinflammatory cytokine and could mediate the inflammatory injury in liver I/R. Rats (n = 6 per group) were subjected to 90 min warm ischemia followed by 0.5 h, 6 h and 24 h reperfusion, respectively to liver transplantation (LTx) after 6 h of cold ischemia followed by 24 h of reperfusion. The expression of MIF, its receptor (cluster of differentiation 74 (CD74)) and the downstream inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)) were analyzed. Peritoneal macrophages were cultured for 6 h alone or in the presence of effluent from cold-preserved livers or effluent depleted of MIF. Warm I/R increased hepatic MIF-mRNA and protein expression. MIF-protein was released into peripheral circulation in vivo with a maximum at 0.5 h after reperfusion. Induction of MIF-expression was associated with the expression of proinflammatory cytokines and its receptor in both models. MIF released by isolated cold preserved livers, induced TNF-α and IL-1β production by cultured peritoneal macrophages. Intrahepatic upregulation of MIF, release into systemic circulation and the associated upregulation of the proinflammatory mediators suggest a role of MIF in mediating the inflammatory response to I/R injury. Blocking experiments will help to elucidate its role as potential molecular target for preventing hepatic I/R injury.     

Macrophage migration inhibitory factor (MIF) -173 polymorphism is associated with clinical erythema nodosum in Löfgren’s syndrome

Introduction: Macrophage migration inhibitory factor (MIF) has been shown to be a key regulator in innate and adaptive immune responses. A single nucleotide polymorphism in the 5′ region of the MIF gene, MIF -1731G/C, is associated with increased MIF protein production, in vivo and in vitro. Associations have been shown between the minor MIF -173C allele and sarcoidosis patients with erythema nodosum (EN). Löfgren’s syndrome is an acute and usually self-remitting phenotype of sarcoidosis. It is defined as having an acute onset with bilateral hilar lymphadenopathy (BHL), fever, erythema nodosum (EN) and/or arthritis.The aim of this study was to investigate whether MIF -173G/C associates with the susceptibility to and the clinical manifestations, i.e. arthritis or EN, of Löfgren’s syndrome.A total of 171 patients with Löfgren’s syndrome and 313 controls were genotyped for a single nucleotide polymorphism at position -173 of the MIF gene (SNP rs755622), using a PCR and a restriction enzyme technique.Results: There were no significant differences found in the MIF -173C allele frequencies between patients with Löfgren’s syndrome and controls. In patients with Löfgren’s syndrome with only EN, a significantly increased frequency of the C minor allele was observed compared to patients with arthritis only (p = 0.0095; OR 3.08, CI: 1.28–7.39).Patients with only EN compared to patients with EN and arthritis showed a significantly increased frequency of the minor C allele (p = 0.044; OR 1.97, CI: 1.01–3.85). But patients with only arthritis compared to patients with EN and arthritis did not show a significant difference in C allele frequency (p = 0.270; OR 0.64, CI: 0.29–1.42).Conclusions: The MIF -173C allele is associated with erythema nodosum in Löfgren’s syndrome, but not with susceptibility to sarcoidosis. This indicates a role for MIF after antigen presenting to the T cell has taken place and the sarcoid inflammatory response has begun.     

Association of the macrophage migration inhibitory factor gene − 173G/C polymorphism with inflammatory bowel disease: A meta-analysis of 4296 subjects

A variety of epidemiologic studies have focused on the association between macrophage migration inhibitory factor (MIF) gene − 173G/C polymorphism and inflammatory bowel disease (IBD). However, results in different studies have been inconsistent. In order to derive a more precise estimation of the associations, we performed this meta-analysis and systematic searches of electronic databases PubMed and Web of Science (up to April 30, 2013). Based on our search criteria, a total of seven eligible studies concerning the MIF − 173G/C polymorphism and IBD risk were included in the final meta-analysis, comprising 2162 IBD cases and 2134 controls. Significant association was found between MIF − 173G/C polymorphism and the risk of IBD when all studies were pooled into the meta-analysis (for C allele vs. G allele: OR = 1.25, 95% CI = 1.12–1.41, p = 0.000; for C/C vs. G/G: OR = 1.71, 95% CI = 1.23–2.39, p = 0.002; for C/C + G/C vs. G/G: OR = 1.24, 95% CI = 1.09–1.42, p = 0.002; for C/C vs. G/C + G/G: OR = 1.67, 95% CI = 1.20–2.33, p = 0.002). Heterogeneity and publication bias did not exist in the overall comparisons. The present meta-analysis suggests an association between the MIF − 173G/C polymorphism and IBD risk. However, due to few studies and the selection bias existed in some studies, the results should be interpreted with caution.     

Attenuation of atherosclerotic lesions in diabetic apolipoprotein E‐deficient mice using gene silencing of macrophage migration inhibitory factor

Macrophage migration inhibitory factor (MIF) involves the pathogenesis of atherosclerosis (AS) and increased plasma MIF levels in diabetes mellitus (DM) patients are associated with AS. Here, we have been suggested that MIF could be a critical contributor for the pathological process of diabetes-associated AS by using adenovirus-mediated RNA interference. First, streptozotocin (STZ)-induced diabetic animal model was constructed in 114 apolipoprotein E-deficient mice (apoE−/− mice) fed on a regular chow diet. Then, the animals were randomly divided into three groups: Adenovirus-mediated MIF interference (Ad-MIFi), Ad-enhanced green fluorescent protein (EGFP) and normal saline (NS) group (n ≈ 33/group). Non-diabetic apoE−/− mice (n = 35) were served as controls. Ad-MIFi, Ad-EGFP and NS were, respectively, injected into the tail vein of mice from Ad-MIFi, Ad-EGFP and NS group, which were injected repeatedly 4 weeks later. Physical, biochemical, morphological and molecular parameters were measured. The results showed that diabetic apoE−/− mice had significantly aggravated atherosclerotic lesions. MIF gene interference attenuated atherosclerotic lesions and stabilized atheromatous plaque, accompanied by the decreased macrophages and lipids deposition and inflammatory cytokines production, improved glucose intolerance and plasma cholesterol level, the decreased ratio of matrix matalloproteinase-2/tissue inhibitor of metalloproteinase-1 and plaque instability index. An increased expression of MIF and its ligand CD74 was also detected in the diabetic patients with coronary artery disease. The results suggest that MIF gene interference is able to inhibit atherosclerotic lesions and increase plaque stability in diabetic apoE−/−mice. MIF inhibition could be a novel and promising approach to the treatment of DM-associated AS.