Increased Macrophage Migration Inhibitory Factor Expression Research Articles

The Macrophage migration inhibitory factor is a vital player in Pan-Cancer by functioning as a M0 Macrophage biomarker

BackgroundThe role of the macrophage migration inhibitory factor (MIF) has recently attracted considerable attention in cancer research; nonetheless, the insights provided by current investigations remain constrained. Our main objective was to investigate its role and the latent mechanisms within the pan-cancer realm. MethodsWe used comprehensive pan-cancer bulk sequencing data and online network tools to investigate the association between MIF expression and patient prognosis, genomic instability, cancer cell stemness, DNA damage repair, and immune infiltration. Furthermore, we validated the relationship between MIF expression and M0 macrophages using single-cell datasets, the SpatialDB database, and fluorescence staining. Additionally, we assessed the therapeutic response using the ROC plotter tool. ResultsWe observed the upregulation of MIF expression across numerous cancer types. Notably, elevated MIF levels were associated with a decline in genomic stability. We found a significant correlation between increased MIF expression and increased expression of mismatch repair genes, stemness features, and homologous recombination genes across diverse malignancies. Subsequently, through an analysis using ESTIMATE and cytokine results, we revealed the involvement of MIF in immune suppression. Then, we validated MIF as a hallmark of the M0 macrophages involved in tumor immunity. Our study suggests an association with other immune-inhibitory cellular populations and restraint of CD8 + T cells. In addition, we conducted a comparative analysis of MIF expression before and after treatment in three distinct sets of therapy responders and non-responders. Intriguingly, we identified notable disparities in MIF expression patterns in bladder urothelial carcinoma and ovarian cancer following particular therapeutic interventions. ConclusionComprehensive pan-cancer analysis revealed notable enrichment of MIF within M0 macrophages, exerting a profound influence on tumor-associated immunosuppression and the intricate machinery of DNA repair.

Recovery of systemic hyperinflammation in patients with severe SARS-CoV-2 infection

Introduction Patients with cardiovascular disease (CVD) and acute SARS-CoV-2 infection might show an altered immune response during COVID-19. Material and methods Twenty-three patients with CVD and SARS-CoV-2 infection were prospectively enrolled and received a cardiological assessment at study entry and during follow-up visit. Inclusion criteria of our study were age older than 18 years, presence of CVD, and acute SARS-CoV-2 infection. The median age of the patient cohort was 69 (IQR 55–79) years. 12 (52.2%) patients were men. Peripheral monocytes and chemokine/cytokine profiles were analysed. Results Numbers of classical and non-classical monocytes were significantly decreased during acute SARS-CoV-2 infection compared to 3-month recovery. While classical monocytes reached the expected level in peripheral blood after 3 months, the number of non-classical monocytes remained significantly reduced. Discussion All three monocyte subsets exhibited changes of established adhesion and activation markers. Interestingly, they also expressed higher levels of pro-inflammatory cytokines like macrophage migration inhibitory factor (MIF) at the time of recovery, although MIF was only slightly increased during the acute phase. Conclusion Changes of monocyte phenotypes and increased MIF expression after 3-month recovery from acute SARS-CoV-2 infection may indicate persistent, possibly long-lasting, pro-inflammatory monocyte function in CVD patients.

Autophagy inhibition in breast cancer cells induces ROS-mediated MIF expression and M1 macrophage polarization

Autophagy can function as a survival mechanism for cancer cells and therefore, its inhibition is currently being explored as a therapy for different cancer types. For breast cancer, triple negative breast cancer (TNBC) is the subtype most sensitive to the inhibition of autophagy; but its inhibition has also been shown to promote ROS-dependent secretion of macrophage migration inhibitory factor (MIF), a pro-tumorigenic cytokine. In this work, we explore the role of MIF in breast cancer, the mechanism by which autophagy inhibition promotes MIF secretion and its effects on neighboring cancer cell signaling and macrophage polarization. We analyzed MIF mRNA expression levels in tumors from breast cancer patients from different subtypes and found that Luminal B, HER2 and Basal subtypes, which are associated to high proliferation, displayed high MIF levels. However, MIF expression had no prognostic relevance in any breast cancer subtype. In addition, we found that autophagy inhibition in 66cl4 TNBC cells increased intracellular Reactive Oxygen Species (ROS) levels, which increased MIF expression and secretion. MIF secreted from 66cl4 TNBC cells induced the activation of MIF-regulated pathways in syngeneic cell lines, increasing Akt phosphorylation in 4T1 cells and ERK phosphorylation in 67NR cells. Regarding MIF/ chemokine receptors, higher levels of CD74 and CXCR2 were found in TNBC tumor cell lines when compared to non-tumorigenic cells and CXCR7 was elevated in the highly metastatic 4T1 cell line. Finally, secreted MIF from autophagy deficient 66cl4 cells induced macrophage polarization towards the M1 subtype. Together, our results indicate an important role for the inhibition of autophagy in the regulation of ROS-mediated MIF gene expression and secretion, with paracrine effects on cancer cell signaling and pro-inflammatory repercussions in macrophage M1 polarization. This data should be considered when considering the inhibition of autophagy as a therapy for different types of cancer.

The Relationship between Functional Promoter Variants of Macrophage Migration Inhibitory Factor and Endometriosis.

Objective Endometriosis is a common gynecological and inflammatory disorder. Macrophage migration inhibitory factor (MIF) is a key pro-inflammatory cytokine that is secreted by accumulated active macrophages in ectopic endometrial tissues. Two promoter polymorphisms of MIF [-794(CATT)5–8/-173G/C] were identified to susceptibility and severity of several immune and inflammatory diseases. We aimed to evaluate the possible association between MIF promoter polymorphisms and susceptibly to endometriosis and its corolation with mRNA level. Materials and Methods This case-control study was performed in Royan Institute from 2015 to 2017. Polymorphisms were evaluated in 106 endometriosis patients and 110 controls. For 17 endometrioma tissues, gene expression studies were conducted during secretory phase of menstrual cycle. Restriction fragment length polymorphism (RFLP) analysis was performed to determine -173G/C polymorphism and -794(CATT)5–8 were detected by sequencing. Quantitative polymerase chain reaction (Q-PCR) was carried out to determine MIF expression level. Results Homozygote of CATT7 was observed only in endometriosis whilst we did not detect the significant allele and genotype variation in both groups. The homozygotes for -794(CATT)5–8 and -173G/C polymorphisms were obtained to estimate the haplotype frequencies. Significantly higher haplotype frequencies were observed for CATT5/G in controls [global P value=0.044]. Additionally, the CATT5/C and CATT7/G haplotypes were not detected in any groups. Expression level of mRNA in ectopic tissue of endometriosis patients with CATT6,7/CC haplotype, were significantly higher compared to other haplotypes including CATT5,5/GG (2.91 fold, P=0.007), CATT5,5/GC (2.48 fold, P=0.047) and CATT6,6/GG (2.08 fold, P=0.046). ConclusionWe report, for the first time, a strong linkage between the decreased repetition of CATT and G allele in control and CATT6/C and CATT7/C haplotypes in endometriosis patients. Increased MIF expression is affected by genetic variants in the MIF promoter in ectopic endometrial tissues. This promoter haplotype might play an important role in the development and establishment of endometriosis.

Macrophage Migration Inhibitory Factor is not Associated with Sarcoidosis Susceptibility or Severity in Whites or Blacks.

Background:Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine, and increased MIF expression has been associated with the development and severity of multiple granulomatous, autoimmune diseases. However, MIF association studies have been discordant in sarcoidosis.Objective:To evaluate associations between macrophage migration inhibitory factor (MIF) promoter polymorphisms and sarcoidosis susceptibility and severity.Methods:Three hundred and fifty one patients with sarcoidosis were recruited through the Genomic Research in Alpha-1 Antitrypsin Deficiency and Sarcoidosis (GRADS) study. Genomic DNA was isolated from serum, and the MIF -173G/C SNP [rs755622] and MIF -794 CATT5–8 microsatellite repeat [rs5844572] were genotyped. Allelic frequencies were compared between cases and healthy controls and associations between MIF alleles and sarcoidosis severity were assessed.Results:The frequencies of the high expression -173C SNP and the low expression -794 CATT5 containing genotypes in white and black sarcoidosis patients were the same as those of healthy controls. High expression MIF alleles were not associated with sarcoidosis severity. Associations between MIF alleles and extrapulmonary sarcoidosis phenotypes were limited by small sample sizes.Conclusions:High expression MIF genotypes were not associated with the susceptibility to or severity of pulmonary sarcoidosis in a large North American cohort. (Sarcoidosis Vasc Diffuse Lung Dis 2020; 37 (3): e2020004)

Macrophage Migration Inhibitory Factor protects cancer cells from immunogenic cell death and impairs anti-tumor immune responses

The Macrophage Migration Inhibitory Factor (MIF) is an inflammatory cytokine that is overexpressed in a number of cancer types, with increased MIF expression often correlating with tumor aggressiveness and poor patient outcomes. In this study, we aimed to better understand the link between primary tumor expression of MIF and increased tumor growth. Using the MMTV-PyMT murine model of breast cancer, we observed that elevated MIF expression promoted tumor appearance and growth. Supporting this, we confirmed our previous observation that higher MIF expression supported tumor growth in the 4T1 murine model of breast cancer. We subsequently discovered that loss of MIF expression in 4T1 cells led to decreased cell numbers and increased apoptosis in vitro under reduced serum culture conditions. We hypothesized that this increase in cell death would promote detection by the host immune system in vivo, which could explain the observed impairment in tumor growth. Supporting this, we demonstrated that loss of MIF expression in the primary tumor led to an increased abundance of intra-tumoral IFNgamma-producing CD4+ and CD8+ T cells, and that depletion of T cells from mice bearing MIF-deficient tumors restored growth to the level of MIF-expressing tumors. Furthermore, we found that MIF depletion from the tumor cells resulted in greater numbers of activated intra-tumoral dendritic cells (DCs). Lastly, we demonstrated that loss of MIF expression led to a robust induction of a specialized form of cell death, immunogenic cell death (ICD), in vitro. Together, our data suggests a model in which MIF expression in the primary tumor dampens the anti-tumor immune response, promoting tumor growth.

TLR7 and TLR8 agonist resiquimod (R848) differently regulates MIF expression in cells and organs

Since its first description in 1966, macrophage migration inhibitory factor (MIF) was found to play a critical role in inflammatory and immune responses as well as in disease pathogenesis especially in tumor pathogenesis and cancer progression. MIF is expressed in different cell types and is associated with many disease severity and tumor pathogenesis. Here, we investigated the influence of TLR7 and TLR8 agonist resiquimod (R848), an immune response inducer used as a prophylactic agent for several infectious diseases as well as anticancer agents and vaccine adjuvant on MIF expression in cells and organs. Humans, mice and rats cell lines from different tissues (blood, retinal, nasopharynx, brain and liver) and C57BL/6J mice organs (brain, liver and spleen) were used for this investigation. In vitro, R848 induced MIF gene overexpression except in brain and liver cells. Furthermore, it enhanced cells ability to release soluble MIF and differently regulated mRNA expression of MIF-related receptors (CD74, CXCR4, CXCR2 and CD44). Its influence on MIF gene expression and MIF proteins release was more consistent in cancer cells. In vivo, a strong positive expression of MIF was observed in different regions in brain and spleen in response to R848 treatment; however in liver, increased MIF expression was observed in hepatocytes only. On the other hand, R848 treatment had induced a slight enhancement of MIF concentration in the plasma of C57BL/6J mice. Taken together, these data suggest that R848 differently regulates MIF mRNA expression depending on organ types and could influence MIF concentration in cellular microenvironment.

Expression of MIF and CD74 in leukemic cell lines: correlation to DR expression destiny.

Invariant chain (Ii) or CD74 is a non-polymorphic glycoprotein, which apart from its role as a chaperone dedicated to MHCII molecules, is known to be a high-affinity receptor for macrophage migration inhibitory factor (MIF). The present study aimed to define the roles of CD74 and MIF in the immune surveillance escape process. Towards this direction, the cell lines HL-60, Raji, K562 and primary pre-B leukemic cells were examined for expression and secretion of MIF. Flow cytometry analysis detected high levels of MIF and intracellular/membrane CD74 expression in all leukemic cells tested, while MIF secretion was shown to be inversely proportional to intracellular HLA-DR (DR) expression. In the MHCII-negative cells, IFN-γ increased MIF expression and induced its secretion in HL-60 and K562 cells, respectively. In K562 cells, CD74 (Iip33Iip35) was shown to co-precipitate with HLA-DOβ (DOβ), inhibiting thus MIF or DR binding. Induced expression of DOα in K562 (DOα-DOβ+) cells in different transfection combinations decreased MIF expression and secretion, while increasing surface DR expression. Thus, MIF could indeed be part of the antigen presentation process.

Inhibition of Macrophage Migration Inhibitory Factor Protects against Inflammation and Matrix Deposition in Kidney Tissues after Injury.

Background. Macrophage migration inhibitory factor (MIF) is an important immunoregulatory cytokine involved in inflammation, which may be one important reason resulting in matrix deposition in renal tissues after injury. However, the underlying mechanisms have not yet been elucidated. Methods and Results. We uncovered a crucial role of MIF in inflammation and collagen deposition in vivo and in vitro. In rats, ureteral obstruction induced tubular injury, matrix accumulation, and inflammatory cell infiltration. Additionally, enhanced MIF levels in the obstructed kidneys were closely related to the increasing numbers of CD68-positive macrophages. These obstruction-induced injuries can be relieved by recanalization, consequently resulting in downregulated expression of MIF and its receptor CD74. Similarly, ischemia reperfusion induced renal injury, and it was accompanied by elevated MIF levels and macrophages infiltration. In cultured tubular epithelial cells (TECs), aristolochic acid (AA) promoted matrix production and increased MIF expression, as well as the release of macrophage-related factors. Inhibition of MIF with an antagonist ISO-1 resulted in the abolishment of these genotypes in AA-treated TECs. Conclusion. MIF plays an important role in macrophage-related inflammation and matrix deposition in kidney tissues following injury. MIF as a specific inhibitor may have therapeutic potential for patients with inflammatory and fibrotic kidney diseases.

Abstract 12206: Endothelial-derived Mif Contributes to Pulmonary Endothelial Cell Proliferation in Human Pulmonary Arterial Hypertension

Introduction: In idiopathic pulmonary arterial hypertension (iPAH), pulmonary-endothelial cells (P-ECs) display phenotypic abnormalities including a greater proliferative response to growth factors and apoptosis resistance; however, the precise underlying mechanisms remain obscure. Excessive MIF (macrophage migration-inhibitory factor) expression during the initial stages of tumor contributes to endothelial proliferation, tumor growth and progression. Hypothesis: We therefore hypothesized that MIF could function as a growth/survival factor promoting the altered P-EC phenotype in iPAH and disease progression. Methods: We examined the expression and the role of MIF in human lung tissues and in cultured pulmonary endothelial cells of control and idiopathic patients. In addition, two complementary animal models of pulmonary hypertension (PH) have been studied: the monocrotaline (MCT) and SU5416 plus chronic hypoxia (SuHx) rat models. Results: In distal pulmonary arteries (PAs) of patients with iPAH, we found a strong immunoreactivity for MIF in the endothelium compared with PAs from control patients. This aberrant endothelial MIF expression is also found in the two experimental models of PH. These in situ observations were replicated in vitro , with cultures P-ECs from patients with iPAH exhibiting increased MIF expression and release compared with control P-ECs. Decreasing MIF expression and signaling by RNA interference or a specific MIF inhibitor called ISO-1 decreased proliferation and induced apoptosis of iPAH P-ECs. Finally, we found that daily treatment of rats with ISO-1 for 2 weeks started 1 week after a subcutaneous monocrotaline injection partially reverses development of pulmonary hypertension. Conclusions: We report here that the pulmonary endothelium of iPAH patients represents a local abnormal source of MIF that could contribute to the hyperproliferative and apoptosis-resistant phenotype of iPAH endothelial cells.

Macrophage Migration Inhibitory Factor in Acute Adipose Tissue Inflammation.

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine and has been implicated in inflammatory diseases. However, little is known about the regulation of MIF in adipose tissue and its impact on wound healing. The aim of this study was to investigate MIF expression in inflamed adipose and determine its role in inflammatory cell recruitment and wound healing. Adipose tissue was harvested from subcutaneous adipose tissue layers of 24 healthy subjects and from adipose tissue adjacent to acutely inflamed wounds of 21 patients undergoing wound debridement. MIF protein and mRNA expression were measured by ELISA and RT-PCR. Cell-specific MIF expression was visualized by immunohistochemistry. The functional role of MIF in cell recruitment was investigated by a chemotaxis assay and by flow cytometry of labeled macrophages that were injected into Mif –/–and wildtype mice. Wound healing was evaluated by an in vitro scratch assay on human fibroblast monolayers. MIF protein levels of native adipose tissue and supernatants from acutely inflamed wounds were significantly elevated when compared to healthy controls. MIF mRNA expression was increased in acutely inflamed adipose tissue indicating the activation of MIF gene transcription in response to adipose tissue inflammation. MIF is expressed in mature adipocytes and in infiltrated macrophages. Peripheral blood mononuclear cell migration was significantly increased towards supernatants derived from inflamed adipose tissue. This effect was partially abrogated by MIF-neutralizing antibodies. Moreover, when compared to wildtype mice, Mif –/–mice showed reduced infiltration of labeled macrophages into LPS-stimulated epididymal fat pads in vivo. Finally, MIF antibodies partially neutralized the detrimental effect of MIF on fibroblast wound healing. Our results indicate that increased MIF expression and rapid activation of the MIF gene in fat tissue adjacent to acute wound healing disorders may play a role in cell recruitment to the site of inflammation and wound healing.

Macrophage migration inhibitory factor in the nucleus of solitary tract decreases blood pressure in SHRs

The macrophage migration inhibitory factor (MIF) is an intracellular inhibitor of the central nervous system actions of angiotensin II on blood pressure. Considering that angiotensin II actions at the nucleus of the solitary tract are important for the maintenance of hypertension in spontaneously hypertensive rats (SHRs), we tested if increased MIF expression in the nucleus of the solitary tract of SHR alters the baseline high blood pressure in these rats. Eight-week-old SHRs or normotensive rats were microinjected with the vector AAV2-CBA-MIF into the nucleus of the solitary tract, resulting in MIF expression predominantly in neurons. Rats also underwent recordings of the mean arterial blood pressure (MAP) and heart rate (via telemetry devices implanted in the abdominal aorta), cardiac- and baroreflex function. Injections of AAV2-CBA-MIF into the nucleus of the solitary tract of SHRs produced significant decreases in the MAP, ranging from 10 to 20 mmHg, compared with age-matched SHRs that had received identical microinjections of the control vector AAV2-CBA-eGFP. This lowered MAP in SHRs was maintained through the end of the experiment at 31 days, and was associated with an improvement in baroreflex function to values observed in normotensive rats. In contrast to SHRs, similar increased MIF expression in the nucleus of the solitary tract of normotensive rats produced no changes in baseline MAP and baroreflex function. These results indicate that an increased expression of MIF within the nucleus of the solitary tract neurons of SHRs lowers blood pressure and restores baroreflex function.

Macrophage migration inhibitory factor reduces apoptosis in cerebral arteriovenous malformations

Purpose: To investigate the expression of macrophage migration inhibitory factor (MIF) in human brain arteriovenous malformations (AVM). Materials and methods: Twelve AVM specimens were obtained from patients who did not received preoperative embolization. MIF levels were measured by Western blot and matrix metalloproteinase 9 (MMP9) levels were measured by reverse transcription PCR. The expression of MIF in brain AVMs was also evaluated by immunohistochemistry and was correlated with apoptosis and the expression of cleaved caspase-3 and MMP9. Results: The expression of MIF, MMP9, and cleaved caspase-3 was elevated in brain AVM vessels. High levels of MIF were primarily found in the endothelium and adventitia, whereas apoptotic cells were concentrated in the smooth muscle layer. Conclusions: Abnormal apoptosis may be involved in the pathogenesis of brain AVM. In addition, increased MIF expression could play an important role regulating the homeostasis of AVM vessels.

Macrophage migration inhibitory factor: a regulator of MMP13 and inflammation in titanium particles-stimulated air pouch in vivo

Macrophage migration inhibitory factor (MIF) is a significant regulator of inflammatory diseases, and local inflammation plays an important role in the aseptic loosening of failed total hip arthroplasty (THA). A high-level MIF expression was found in the interfacial membrane around implants. However, the cause of increased MIF expression and the action of MIF in the process of aseptic-loosening implant is still unknown. This study is to investigate MIF expression and its upregulating effect on matrix metalloproteinases (MMPs) expression in the particles-stimulated air pouches in mice that appear to closely resemble the interfacial membranes. A total of 48 murine air pouches were divided into four groups, and were injected with PBS, titanium particles suspensions, titanium particles suspensions with neutralizing antibody of MIF, and titanium particles suspensions with normal IgG, respectively. Histological and cytokine responses were evaluated. The inflammatory reaction of air pouch membranes induced by titanium particles was significantly suppressed by neutralizing antibody. The levels of MIF protein and mRNA were significantly increased in the titanium particles-stimulated air pouch membranes compared with the control groups. So were the levels of MMP13 protein and mRNA. However, the levels of MMP13 protein and mRNA were significantly reduced by neutralizing antibody. Our study demonstrates that titanium particles can cause the air pouch membranes to increase the expression of MIF, which upregulates the production of MMP13 and induces inflammatory reaction in vivo. The results indicate that MIF may play an important role in the process of aseptic-loosening implants after THA.

Impaired Macrophage Migration Inhibitory Factor–AMP-Activated Protein Kinase Activation and Ischemic Recovery in the Senescent Heart

Elderly patients are more sensitive than younger patients to myocardial ischemia, which results in higher mortality. We investigated how aging affects the cardioprotective AMP-activated protein kinase (AMPK) signaling pathway. Ischemic AMPK activation was impaired in aged compared with young murine hearts. The expression and secretion of the AMPK upstream regulator, macrophage migration inhibitory factor (MIF), were lower in aged compared with young adult hearts. Additionally, the levels of hypoxia-inducible factor 1alpha, a known transcriptional activator of MIF, were reduced in aged compared with young hearts. Ischemia-induced AMPK activation in MIF knockout mice was blunted, leading to greater contractile dysfunction in MIF-deficient than in wild-type hearts. Furthermore, intramyocardial injection of adenovirus encoding MIF in aged mice increased MIF expression and ischemic AMPK activation and reduced infarct size. An impaired MIF-AMPK activation response in senescence thus may be attributed to an aging-associated defect in hypoxia-inducible factor 1alpha, the transcription factor for MIF. In the clinical setting, impaired cardiac hypoxia-inducible factor 1alpha activation and consequent reduced MIF expression may play an important role in the increased susceptibility to myocardial ischemia observed in older cardiac patients.

Macrophage Migration Inhibitory Factor Promotes Colorectal Cancer

A growing body of evidence implicates macrophage migration inhibitory factor (MIF) in tumorigenesis and metastasis. In this study, we investigated whether MIF expression was associated with clinicopathologic features of colorectal carcinoma (CRC), especially in tumors with hepatic metastasis, and whether neutralization of endogenous MIF using anti-MIF therapeutics would inhibit tumor growth and/or decrease the frequency of colorectal hepatic metastases in a mouse colon carcinoma model. The concentration of serum MIF was positively correlated with an increased risk of hepatic metastasis in human patients with CRC (R = 1.25, 95% confidence internal = 1.02-1.52, P = 0.03). MIF was also dramatically upregulated in human colorectal tissue, with 20-40 times as many MIF-positive cells found in the mucosa of patients with CRC than in normal tissue (P < 0.001 ANOVA). Moreover, in those patients with metastatic colorectal cancer in the liver, MIF-positive cells were similarly increased in the diseased hepatic tissue. This increased MIF expression was restricted to diseased tissue and not found in areas of the liver with normal morphology. In subsequent in vitro experiments, we found that addition of recombinant MIF to colonic cell lines significantly increased their invasive properties and the expression of several genes (for example, matrix metalloproteinase 9 and vascular endothelial growth factor) known to be upregulated in cancerous tissue. Finally, we treated mice that had been given CT26 colon carcinoma cell transplants with anti-MIF therapeutics--either the MIF-specific inhibitor ISO-1 or neutralizing anti-MIF antibodies--and observed a significant reduction in tumor burden relative to vehicle-treated animals. Taken together, these data demonstrate that MIF expression was not only correlated with the presence of colorectal cancer but also may play a direct role in cancer development.

The levels of macrophage migration inhibitory factor as an indicator of disease activity and severity in adult-onset Still's disease

Objectives: This study investigated the levels of macrophage migration inhibitory factor (MIF) in adult-onset Still's disease (AOSD) and explored the role of this pro-inflammatory cytokine in the systemic inflammation of AOSD. Design and methods: Serum MIF levels were measured by ELISA in patients with AOSD and controls. Intracellular MIF production by peripheral blood leukocytes was detected by three-color flow cytometry. Results: Serum MIF levels were significantly increased in patients with AOSD. Serum MIF levels were significantly higher in AOSD patients with sore throat, myalgias, splenomegaly, or pleuritis, and were closely correlated with clinical disease severity and activity. Examined by flow cytometry, the intracellular MIF levels in monocytes and T-lymphocytes from AOSD patients were significantly higher than those from healthy subjects. Conclusion: These data represent the first demonstration of increased MIF expression in AOSD, and suggest that MIF may be an important marker for disease evaluation and monitoring.

Macrophage migration inhibitory factor (MIF) gene polymorphisms are associated with increased prostate cancer incidence

Recurrent or persistent inflammation has emerged as an important factor in cancer development. Overexpression of macrophage migration inhibitory factor (MIF), an upstream regulator of innate immunity with pleiotropic effects on cell proliferation, has been implicated in prostate cancer (CaP). Two polymorphisms in the promoter of the MIF gene (-173G to C transition and seven copies of the -794 CATT repeat) are associated with increased MIF expression in vivo and poor prognosis in autoimmune diseases. We conducted a retrospective analysis of 131 CaP patients and 128 controls from a group of Veterans' Administration patients undergoing routine prostate-specific antigen screening. Patients with CaP were enrolled regardless of treatment. Inclusion criteria for the control group were absence of documented diagnosis of cancer and/or chronic inflammation within patient computerized records. Logistic regression demonstrated a significant association between CaP and the -173G/C, the -173C/C and the -794 7-CATT MIF polymorphisms (P<0.001). Patients with the -794 7-CATT allele had an increased risk of CaP recurrence at 5 years. Individuals with -173G/C, -173C/C and -794 7-CATT MIF genotypes have an increased incidence of CaP and these genotypes may serve as an independent marker for cancer recurrence.

Regulation of Human Lung Adenocarcinoma Cell Migration and Invasion by Macrophage Migration Inhibitory Factor

Macrophage migration inhibitory factor (MIF) is expressed and secreted in response to mitogens and integrin-dependent cell adhesion. Once released, autocrine MIF promotes the activation of RhoA GTPase leading to cell cycle progression in rodent fibroblasts. We now report that small interfering RNA-mediated knockdown of MIF and MIF small molecule antagonism results in a greater than 90% loss of both the migratory and invasive potential of human lung adenocarcinoma cells. Correlating with these phenotypes is a substantial reduction in steady state as well as serum-induced effector binding activity of the Rho GTPase family member, Rac1, in MIF-deficient cells. Conversely, MIF overexpression by adenovirus in human lung adenocarcinoma cells induces a dramatic enhancement of cell migration, and co-expression of a dominant interfering mutant of Rac1 (Rac1(N17)) completely abrogates this effect. Finally, our results indicate that MIF depletion results in defective partitioning of Rac1 to caveolin-containing membrane microdomains, raising the possibility that MIF promotes Rac1 activity and subsequent tumor cell motility through lipid raft stabilization.

Oxygen regulation of macrophage migration inhibitory factor in human placenta

Macrophage migration inhibitory factor (MIF) is an important proinflammatory cytokine involved in regulation of macrophage function. In addition, MIF may also play a role in murine and human reproduction. Although both first trimester trophoblast and decidua express MIF, the regulation and functional significance of this cytokine during human placental development remains unclear. We assessed MIF expression throughout normal human placental development, as well as in in vitro (chorionic villous explants) and in vivo (high altitude placentae) models of human placental hypoxia. Dimethyloxalylglycine (DMOG), which stabilizes hypoxia inducible factor-1 under normoxic conditions, was also used to mimic the effects of hypoxia on MIF expression. Quantitative real-time PCR and Western blot analysis showed high MIF protein and mRNA expression at 7-10 wk and lower levels at 11-12 wk until term. Exposure of villous explants to 3% O(2) resulted in increased MIF expression and secretion relative to standard conditions (20% O(2)). DMOG treatment under 20% O(2) increased MIF expression. In situ hybridization and immunohistochemistry showed elevated MIF expression in low oxygen-induced extravillous trophoblast cells. Finally, a significant increase in MIF transcript was observed in placental tissues from high-altitude pregnancies. Hence, three experimental models of placental hypoxia (early gestation, DMOG treatment, and high altitude) converge in stimulating increased MIF, supporting the conclusion that placental-derived MIF is an oxygen-responsive cytokine highly expressed in physiological in vivo and in in vitro low oxygen conditions.