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Gastric epithelial expression of macrophage migration inhibitory factor is not altered by Helicobacter pylori infection in humans.

BACKGROUND: Recent reports have shown an upregulation of macrophage migration inhibitory factor (MIF) during gastric ulcer development in a rat model and elevated counts of MIF-positive cells in biopsies from Helicobacter pylori-infected patients. H. pylori infection is a proven cofactor in humans causing gastritis and gastric ulcers. The aim of this study was to characterize MIF expression in human gastric epithelial cells in response to H. pylori. METHODS: MIF mRNA and MIF protein expression was detected in human gastric epithelial cell lines after stimulation with proinflammatory cytokines or infection with H. pylori (cagA+/vacA+) using real-time reverse transcriptase-polymerase and enzyme-linked immunosorbent assay. Interleukin-8 secretion was measured as positive control. MIF mRNA and MIF protein expression was assessed in H. pylori-positive and -negative human gastric biopsy samples. RESULTS: While interleukin-8 mRNA expression and interleukin-8 secretion were upregulated in gastric epithelial cells in vitro after H. pylori infection, no changes in MIF mRNA expression and MIF secretion could be detected. We found no significant differences in MIF expression in total RNA extracted from gastric biopsy tissue when comparing H. pylori-positive to control patients. Likewise, MIF protein expression in gastric epithelium was unaffected by H. pylori infection as compared to uninfected tissue. CONCLUSIONS: While an increased MIF expression and positive effects of MIF blockade in ulcer healing have been shown in a rodent model and elevated numbers of MIF-positive cells have been found in H. pylori-infected human tissue, we herein could not confirm any differences in human gastric epithelial MIF expression and secretion after H. pylori infection in vitro and in vivo.

Biopsy↗

Macrophage migration inhibitory factor increases neuronal delayed rectifier K+ current.

Macrophage migration inhibitory factor (MIF) has widespread actions in the immune, endocrine, and nervous systems. Previously, we reported that increases in the intracellular levels of MIF depress the firing of hypothalamus/brain stem neurons in culture, including the chronotropic actions of angiotensin II. The objective of this study was to investigate the effects of MIF on delayed rectifier K+ current (I(Kv)), one of the component currents whose activity contributes to neuronal firing. Intracellular perfusion of MIF (80 nM) into Sprague-Dawley rat neuronal cultures caused a significant increase in I(Kv), as measured by patch-clamp recordings. This effect was apparent by 3 min, and was maximal after 20-30 min. I(Kv) current density (pA/pF) increased from 31.58 +/- 2.36 in controls to 41.88 +/- 3.76 in MIF-treated neurons (mean +/- SE; n = 9; P < 0.01). MIF that had been inactivated by boiling did not alter I(Kv), and MIF-neutralizing antibodies abolished the action of recombinant MIF (rMIF). The stimulatory effect of MIF on I(Kv) current density was mimicked by intracellular application of either P1S-MIF (80 nM) or the peptide MIF-(50-65) (0.8-8 microM), both of which harbor the thiol-protein oxidoreductase (TPOR) activity of the MIF molecule. Conversely, neither C60S-MIF (80 nM) nor the MIF homologue D-dopachrome tautomerase (80 nM), both of which lack TPOR activity, altered I(Kv). Finally, the increase in I(Kv) produced by rMIF was abolished by the superoxide scavenger Tiron (1 mM). These studies indicate that the neuronal action of MIF includes a stimulatory action on I(Kv) that may be mediated by a TPOR/superoxide-scavenging mechanism.

Action Potentials↗

Macrophage migration inhibitory factor is released from pituitary folliculo-stellate-like cells by endotoxin and dexamethasone and attenuates the steroid-induced inhibition of interleukin 6 release.

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine produced by peripheral immune cells and also by endocrine cells in the anterior pituitary gland. MIF exerts its proinflammatory actions in the host-defense system by blocking the inhibitory effects of glucocorticoids on the release of other proinflammatory cytokines (e.g. IL-1, IL-6, TNFalpha). Reports that pituitary folliculo-stellate (FS) cells share many characteristics with immune cells led us to propose that these cells may serve as an additional source of MIF in the pituitary and that pituitary-derived MIF may act in an autocrine or paracrine manner to modulate endotoxin-induced cytokine release from FS cells. In the present study we addressed this hypothesis by using 1) immunohistochemistry to localize MIF in primary pituitary tissue and 2) well-characterized FS (TtT/GF), corticotroph (AtT20), and macrophage/monocyte (RAW 264.7) cell lines to explore the effects of CRH, endotoxin, and dexamethasone on MIF release and to examine the effects of MIF on IL-6 release. Our immunohistochemical study showed that MIF is expressed in abundance in S100-positive FS cells and also in other pituitary cell types. All three cell lines expressed MIF protein and responded to endotoxin (10-1000 ng/ml, 24 h) and dexamethasone (100 pM to 10 nM, 24 h) with concentration-dependent increases in MIF release. CRH (10-100 nM) also stimulated MIF release from AtT20 cells but, unlike endotoxin and dexamethasone, it had no effect on MIF release from TtT/GF or RAW cells. Recombinant MIF did not affect the basal release of IL-6 from TtT/GF cells; however, it effectively reversed the inhibitory effects of dexamethasone (1 nM) on the endotoxin-induced release of IL-6 from these cells. The results suggest that the FS cells are both a source of and a target for MIF and raise the possibility that MIF serves as a paracrine/autocrine factor in the pituitary gland that contributes to the protective neuroendocrine response to endotoxin.

Animals↗

Migration inhibitory factor induces killing of Leishmania major by macrophages: dependence on reactive nitrogen intermediates and endogenous TNF-alpha.

Macrophage migration inhibitory factor (MIF) is a product of activated T cells, anterior pituitary cells, and macrophages. MIF plays an important role in LPS-induced shock and delayed-type hypersensitivity. Furthermore, MIF exhibits a proinflammatory spectrum of action, promoting TNF-alpha production by macrophages, and counter-regulates glucocorticoid suppression of cytokine production. Here, we report that purified recombinant MIF activates murine macrophages to kill Leishmania major, with maximal effects at concentrations above 1 microg/ml. This MIF-mediated activation is specific, since it can be blocked completely by anti-MIF mAb. The MIF-mediated activation is dependent on TNF-alpha produced endogenously by macrophages, because the administration of anti-TNF-alpha antiserum markedly reduced the MIF effect. No MIF-mediated activation was observed in macrophages derived from TNF receptor p55 knockout mice, thus demonstrating the requirement of the smaller TNF receptor molecule for autocrine TNF-alpha signaling. A highly specific inhibitor of the inducible nitric oxide synthase (iNOS), L-N6-(1-iminoethyl)lysine, dihydrochloride, also inhibited the action of MIF, suggesting an important role for iNOS in the antiparasitic properties of MIF. In line with this, no MIF-mediated activation was detected analyzing macrophages derived from iNOS-deficient mice. The effect of MIF was blocked completely by the macrophage-deactivating cytokines IL-10, IL-13, and TGF-beta. Finally, the expression of MIF mRNA and protein was up-regulated in lymph nodes of mice during the first week after infection with L. major. MIF therefore represents a cytokine involved not only in the recruitment of proinflammatory cells during infection but also in the complex regulation of the antimicrobial activity of these cells.

Animals↗

Regulation of macrophage migration inhibitory factor by endogenous glucocorticoids in rat adjuvant-induced arthritis.

OBJECTIVE: To explore the regulation of macrophage migration inhibitory factor (MIF) by endogenous glucocorticoids in adjuvant-induced arthritis (AIA). METHODS: Adrenalectomy or sham operation was performed 2 days prior to adjuvant arthritis induction. Synovial explant supernatant levels of MIF and tumor necrosis factor alpha (TNFalpha) were measured by enzyme-linked immunosorbent assay (ELISA). Synovial MIF immunostaining was detected by 3-layer immunohistochemistry. Serum MIF levels were measured by Western blotting. Pituitary MIF release was measured by ELISA. Anti-MIF monoclonal antibody (mAb) or isotype-matched control antibody was administered to adrenalectomized (ADX) animals throughout AIA development. RESULTS: Compared with sham operation, adrenalectomy was associated with significant exacerbation of clinical disease parameters (P < 0.05). Adrenalectomy was associated with significantly reduced levels of synovial MIF, but not TNFalpha. In contrast, adrenalectomy was associated with increased serum MIF levels. Concomitant increased pituitary MIF levels were observed in ADX rats, consistent with the pituitary being the principal source of this increase. The administration of specific anti-MIF mAb conferred 100% protection from lethality during arthritis development and decreased arthritis disease expression. CONCLUSION: These findings provide the first in vivo confirmation of the observation that endogenous glucocorticoids are involved in the regulation of MIF in a site of inflammation, and that local and systemic MIF production are differentially regulated in this setting. The reversal of disease in ADX rats by anti-MIF mAb suggests that balance between glucocorticoids and MIF may influence the expression of inflammatory disease.

Adrenalectomy↗

Control of fibroblast-like synoviocyte proliferation by macrophage migration inhibitory factor.

OBJECTIVE: The hyperplasia of fibroblast-like synoviocytes (FLS) is considered essential to the evolution of joint destruction in rheumatoid arthritis (RA), but the mechanisms underlying FLS proliferation remain poorly understood. Macrophage migration inhibitory factor (MIF) is a cytokine that has recently been shown to exert proinflammatory effects on RA FLS. This study sought to identify the mechanisms of activation of FLS by MIF, and to assess the effects of MIF on synovial cell proliferation. METHODS: Human RA FLS were treated with recombinant MIF, interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF alpha), and/or anti-MIF monoclonal antibodies (mAb). Proliferation was measured with tritiated thymidine incorporation. Nuclear factor kappa B (NF-kappa B) and mitogen-activated protein (MAP) kinase activation were measured with immunohistochemistry and Western blotting, respectively. RESULTS: FLS proliferation was significantly increased by MIF. IL-1 beta and TNFalpha also induced proliferation, but these effects were prevented by neutralization with anti-MIF mAb. Activation of NF-kappa B was induced by IL-1 beta, but not by MIF. Anti-MIF mAb had no effect on IL-1 beta-induced NF-kappa B nuclear translocation. By contrast, MIF induced phosphorylation of extracellular signal-regulated kinase (ERK) MAP kinase. ERK antagonism, but not NF-kappa B antagonism, prevented the effect of MIF on FLS proliferation. CONCLUSION: These data suggest that MIF may regulate RA synovial hyperplasia by acting directly and via involvement in the effects of IL-1 beta and TNFalpha. In addition, the effects of MIF on FLS activation are independent of NF-kappa B, and dependent on ERK MAP kinase. These data suggest an important therapeutic potential for MIF antagonism in RA.

Cell Division↗

Macrophage migration inhibitory factor evaluation compared with prostate specific antigen as a biomarker in patients with prostate carcinoma.

BACKGROUND: Cytokines are polypeptides that constitute a class of chemical mediator molecules that modulate cell growth by inducing specific target gene expression. The objective of this study was to evaluate the clinical usefulness of serum evaluation of the cytokine macrophage migration inhibitory factor (MIF) in patients undergoing routine prostate specific antigen (PSA) screening. METHODS: In this preliminary, retrospective study, the authors report the development of an enzyme-linked immunosorbent assay (ELISA) for MIF determination in serum samples. A polymerase chain reaction (PCR)-based assay investigated associations between MIF expression and prostate carcinoma (CaP). The authors developed a relative quantitative reverse transcriptase-PCR assay to determine MIF mRNA amounts within laser-capture microscopy (LCM)-dissected prostate epithelial cells. RESULTS: A comparison of serum MIF levels and total PSA levels identified a positive correlation (correlation coefficient [r2] = 0.61; P < 0.001; n = 509 patients), suggesting an association between elevated serum concentrations of these proteins and CaP. A correlation of serum MIF levels with a diagnosis of CaP demonstrated that patients with a previous CaP diagnosis had significantly elevated serum MIF concentrations (mean +/- standard deviation, 6.8 +/- 0.87 ng/mL; P < 0.001). To associate altered serum MIF levels with MIF mRNA expression within prostate epithelial cells, LCM-dissected prostate epithelial cells (formalin fixed biopsies from three different patients) were used to determine MIF mRNA amounts by PCR analysis. On average, MIF mRNA amounts were 6.5 times higher in CaP epithelial cells that were invasive to the margin compared with MIF mRNA amounts in normal prostate epithelial cells within the same biopsy specimen. CONCLUSIONS: The ELISA data from the current study suggested an association between increased MIF expression and CaP and suggested that serum MIF concentration may serve as a prognostic marker for CaP.

Aged↗

Overexpression of macrophage migration inhibitory factor induces angiogenesis and deteriorates prognosis after radical resection for hepatocellular carcinoma.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a pivotal cytokine that regulates inflammatory and immune responses. Recently, many investigators reported that MIF is expressed highly in several tumors, including hepatocellular carcinoma (HCC). However, the role of MIF in tumor angiogenesis and patient prognosis has not been examined in patients with HCC. METHODS: The authors evaluated MIF expression in 56 samples of HCC by Western blot analysis, and the results were correlated with clinicopathologic factors and patient prognosis. MIF localization was determined by immunohistochemical methods, and the results were compared with tumor microvessel density (MVD), as assessed by anti-CD34 antibody. Furthermore, to validate the role of MIF in angiogenesis, both MIF expression during culture of HCC cells (using the Hep3B, HepG2, and Huh7 cell lines) under hypoxic condition and the angiogenic potential of recombinant MIF in an in vitro angiogenic model were examined. RESULTS: Tumors with high MIF expression had high alpha-fetoprotein levels (P = 0.049) and frequent intrahepatic recurrence (P = 0.043). Immunohistochemical MIF scores had a significant correlation with MVD (P = 0.007). Patients who had tumors with high MIF expression levels had a significantly worse (P = 0.025) disease-free survival, and this finding remained significant as an independent prognostic factor in the multivariate analysis. Hep3B cells had high expression of MIF at 6 hours and 12 hours after hypoxic stress and exogenous MIF stimulated endothelial tube formation in in vitro angiogenesis. CONCLUSIONS: The current findings suggest that MIF expression may play a pivotal role in the dismal prognosis of patients with HCC that may be attributable to the modulation of angiogenesis.

Aged↗

Macrophage migration inhibitory factor: roles in regulating tumor cell migration and expression of angiogenic factors in hepatocellular carcinoma.

Macrophage migration inhibitory factor (MIF) may contribute to multiple aspects of tumor progression, including control of cell proliferation, differentiation, cell survival and angiogenesis. However, the potential roles of MIF in regulating hepatocellular carcinoma (HCC) tumor cell migration and the expression of angiogenic factors by HCC tumor cells have not been studied yet. In our study, we reported that intracellular MIF mRNA and protein were overexpressed in HCC tissues compared to nontumor tissues by using in situ hybridization and immunohistochemic staining. HCC tumor cell lines also secreted large amounts of MIF into the supernatants of tumor cell culture. To assess the role of MIF in HCC, we employed the transwell invasion chamber to study the effect of MIF on tumor cell migration. Our results showed that recombinant MIF and the supernatants of tumor cell line culture could enhance the invasion and migration of HCC cells. This effect can be inhibited by the addition of a neutralizing anti-MIF antibody. We observed that increased MIF serum levels correlated with higher levels of interleukin-8 (IL-8) in the sera of patients with HCC than in normal volunteers. We therefore hypothesized that MIF may regulate the production of angiogenic factors by HCC cells. To test this hypothesis, we examined the effect of MIF treatment on vascular endothelial growth factor (VEGF) and IL-8 expression by HCC cell lines. MIF induced a significant dose-dependent increase in IL-8 and VEGF production. Taken together, our results indicated that MIF may act as an autocrine-acting factor that stimulates angiogenesis and metastasis in HCC by promoting expression of angiogenic factors and migration of tumor cells. A more detailed understanding of the MIF regulatory mechanisms involved may provide insight into new direction in the treatment of HCC.

Adult↗

Role for macrophage migration inhibitory factor in acute respiratory distress syndrome.

The critical role of macrophage migration inhibitory factor (MIF) in mediating inflammatory lung injury in acute respiratory distress syndrome (ARDS) has been raised recently. The present study has identified enhanced MIF protein expression in alveolar capillary endothelium and infiltrating macrophages in lung tissues from ARDS patients. The possibility that MIF up-regulates its synthesis in an autocrine fashion in ARDS was tested using cultured endothelial cells stimulated with MIF and a murine model of lipopolysaccharide (LPS)-induced acute lung injury. MIF induced significant MIF and tumour necrosis factor (TNF)-alpha synthesis in cultured endothelial cells and the effect was blocked by neutralizing anti-MIF antibody. A similar blocking effect was observed when MIF-stimulated endothelial cells were pretreated with neutralizing anti-TNF-alpha antibody or glucocorticoid, supporting the notion that MIF induced TNF-alpha production via an amplifying pro-inflammatory loop. Treatment with anti-MIF or glucocorticoid effectively attenuated pulmonary pathology and the synthesis of MIF or TNF-alpha in mice with LPS-induced acute lung injury. Mildly augmented expression of aquaporin 1 (AQP1) was also detected in alveolar capillary endothelium in ARDS. In vitro studies revealed that both MIF and TNF-alpha induced a small increase of AQP1 synthesis in cultured endothelial cells. These findings suggest that MIF plays a crucial pathological role leading to alveolar inflammation in ARDS. Anti-MIF and early glucocorticoid therapy may represent a novel therapeutic approach for reducing alveolar inflammation in ARDS.

Adult↗

Diagnostic validity of macrophage migration inhibitory factor in serum of patients with prostate cancer: a re-evaluation.

BACKGROUND: Recent studies suggest that macrophage migration inhibitory factor (MIF) in serum is of prognostic significance for prostate cancer. The aim of this study was to re-evaluate this hypothesis. METHODS: Serum MIF levels were measured in healthy men (n = 86), untreated patients with benign prostate hyperplasia (BPH; n = 50), prostate cancer (PCa; n = 163), and after radical prostatectomy for 3 days (n = 5). PCa patients were classified according to the TNM system and the WHO grading scale. Prostate specific antigen (PSA) and C-reactive protein (CRP) were additionally determined. RESULTS: The MIF concentrations of healthy men and BPH patients did not differ (mean +/- SD, 2.08 +/- 1.08 microg/L vs. 2.04 +/- 1.08 microg/L), whereas the mean value of MIF in PCa patients was significantly decreased (1.77 +/- 1.12 microg/L). There was no any correlation between MIF and PSA (r(s) = -0.049, P = 0.271). MIF concentrations in patients with T1 tumors were higher than in those with T2 tumors (2.29 +/- 1.26 vs. 1.67 +/- 1.11 microg/L; P = 0.044). No any effect of grading was observed. After prostatectomy, the changes of PSA and MIF were not always concordant as MIF partly increased while PSA continuously decreased. Analyses of receiver-operating curves and logistic regressions did not show that MIF alone or MIF related variables (MIF/tPSA; fPSA/(tPSA x MIF); fPSA x MIF/tPSA) could improve specificity or sensitivity to detect prostate cancer in comparison to total PSA. CONCLUSION: Serum MIF alone or MIF to PSA related variables did not seem suitable for providing additional information on PCa patients. That re-evaluated diagnostic validity of MIF was in contrast to results by another group shown previously.

Aged↗

High expression of macrophage migration inhibitory factor in human melanoma cells and its role in tumor cell growth and angiogenesis.

Macrophage migration inhibitory factor (MIF) is known to function as a cytokine, hormone, and glucocorticoid-induced immunoregulator. In this study, we reported for the first time that human melanocytes and melanoma cells express MIF mRNA and produce MIF protein. Immunohistochemical analysis demonstrated that MIF was mostly localized in the cytoplasm of melanocytes and G361 cells, a widely available human melanoma cell line. In particular, strong positive staining was observed at the dendrites of these cells. Expression of MIF mRNA and production of MIF protein were much higher in human melanoma cells such as G361, A375, and L32 than in normal cultured melanocytes. To assess the role of MIF overexpression in melanoma cells, G361 cells were transfected with an antisense human MIF plasmid. The results demonstrated that the cell growth rate of the transfected cells was markedly suppressed, suggesting that MIF participates in the mechanism of proliferation of melanoma cells. To further evaluate the function of MIF, we employed the Boyden chamber method to examine the effect on tumor cell migration and found that MIF enhanced the migration of G361 cells in a dose-dependent manner. Furthermore, we administered anti-MIF antibody into tumor (G361 cells in a Millipore chamber)-bearing mice to assess the effect on tumor-associated angiogenesis. The anti-MIF antibody significantly suppressed tumor-induced angiogenesis. Taken together, these results indicated that it is likely that MIF may function as a novel growth factor that stimulates incessant growth and invasion of melanoma concomitant with neovascularization.

Animals↗

Inhibition of tumor growth and metastasis in vitro and in vivo by targeting macrophage migration inhibitory factor in human neuroblastoma.

Macrophage migration inhibitory factor (MIF) has been defined as a novel oncogene. Our previous results have shown that MIF may contribute to the progression of neuroblastoma by (a) inducing N-Myc expression and (b) upregulating the expression of angiogenic factors. The aim of this study was to test whether tumor growth could be inhibited by reduction of endogenous MIF expression in neuroblastoma and clarify the molecular mechanisms underlying MIF reduction on the control of neuroblastoma growth. We established human neuroblastoma cell lines stably expressing antisense MIF (AS-MIF) cDNA. These stable transfectants were characterized by cell proliferation, gene expression profile, tumorigenicity and metastasis in vitro and in vivo. Decreased MIF expression was observed after transfection with AS-MIF in neuroblastoma cells and downregulation of MIF expression significantly correlated with decreased expression of N-Myc, Ras, c-Met and TrkB at protein level. Affymetrix microarray analysis revealed that expression of IL-8 and c-met was inhibited and neuroblastoma-favorable genes such as EPHB6 and BLU were upregulated in MIF reduced cells. Neuroblastoma cell growth exhibited a nearly 80% reduction in AS-MIF transfectants in vitro. Furthermore, mice in which tumors formed after subcutaneous injection of AS-MIF transfectants showed a 90% reduction in tumor growth compared to control. Metastasis in mice was also suppressed dramatically. Our data demonstrate that targeting MIF expression is a promising therapeutic strategy in human neuroblastoma therapy, and also identifies the MIF target genes for further study.

Animals↗

Rapid purification and characterization of L-dopachrome-methyl ester tautomerase (macrophage-migration-inhibitory factor) from Trichinella spiralis, Trichuris muris and Brugia pahangi.

Macrophage-migration-inhibition factor (MIF) is an essential stimulator of mammalian T-lymphocyte-dependent adaptive immunity, hence MIF orthologues might be expressed by infectious organisms as an immunosubversive stratagem. Since MIF actively catalyses the tautomerization of the methyl ester of l-dopachrome (using dopachrome tautomerase), the occurrence of MIF orthologues in several parasitic helminths was investigated by assaying and characterizing such activity. Evidence of MIF orthologues (dopachrome tautomerase) was found in the soluble fraction of the nematodes Trichinella spiralis (stage 4 larvae) and Trichuris muris (adults), and the filarial nematode Brugia pahangi (adults). The MIF orthologues of Tr. muris (TmMIF) and B. pahangi (BpMIF) were purified to homogeneity using phenyl-agarose chromatography, that of T. spiralis (TsMIF) required a further step: cation-exchange FPLC. Retention time on reverse-phase HPLC and Mr on SDS/PAGE of the nematode MIFs were similar to those of human MIF. N-terminal sequences (19 residues) of TsMIF and TmMIF showed 47 and 36% identity, respectively, with human MIF. The N-terminal sequence of BpMIF (14 residues) was identical to that of an MIF orthologue in the genome of B. malayi (Swiss-Prot, P91850) and showed 43% identity to either human or TsMIF. TsMIF had 10-fold higher dopachrome tautomerase activity than MIF from the other sources. The enzyme activities of TsMIF, BpMIF and TmMIF were less sensitive to inhibition by haematin (I50: >15 microM, >15 microM and 2.6 microM, respectively) than that of human MIF (I50 0.2 microM). Significant dopachrome tautomerase or phenyl-agarose-purifiable MIF-like protein was not detected in the soluble fraction of the nematodes Heligmosomoides polygyrus and Nippostrongylus brasiliensis, the cestode Hymenolepis diminuta, or the trematodes Schistosoma mansoni, S. japonicum and S. haematobium, or the free-living nematode, Caenorhabditis elegans, which does contain an MIF-related gene.

Amino Acid Sequence↗

Expression of macrophage migration inhibitory factor in human glomerulonephritis.

BACKGROUND: We have recently demonstrated that macrophage migration inhibitory factor (MIF) plays a pathogenic role in experimental glomerulonephritis (GN). The aim of the current study was to investigate MIF expression in human GN. METHODS: MIF expression was examined by in situ hybridization and immunohistochemistry staining in 65 biopsies from a variety of glomerulonephridities. RESULTS: There is constitutive expression of MIF mRNA and protein in normal human kidney that is largely restricted to tubular epithelial cells and to some glomerular epithelial cells. There was little change in the pattern of MIF expression in nonproliferative forms of GN such as minimal change disease and membranous GN. However, there was a marked increase in both glomerular and tubular MIF expression in proliferative forms of GN, including focal segmental glomerulosclerosis (FGS), lupus nephritis, crescentic GN, and mesangiocapillary proliferative GN. The prominent macrophage and T-cell infiltrate in these diseases were largely restricted to areas with marked up-regulation of MIF expression, contributing to glomerular hypercellularity, glomerular focal segmental lesions, crescent formation, tubulitis, and granulomatous lesions. De novo MIF expression was evident in glomerular endothelial cells and mesangial cells in proliferative forms of GN. In addition, many infiltrating macrophages and T cells showed MIF mRNA and protein expression. Quantitative analysis found that increased glomerular and tubular MIF expression gave a highly significant correlation with macrophage and T-cell accumulation, the severity of histologic lesions, and the loss of creatinine clearance. CONCLUSIONS: Renal MIF expression is markedly up-regulated in proliferative forms of human GN, and this correlates with leukocyte infiltration, histologic damage, and renal function impairment. These results suggest that MIF may be an important mediator of renal injury in progressive forms of human GN. Based on these findings, together with the known pathogenic role of MIF in experimental GN, we propose that MIF is an attractive therapeutic target in the treatment of progressive forms of GN.

Adolescent↗

Amelioration of dextran sulfate sodium-induced colitis by anti-macrophage migration inhibitory factor antibody in mice.

BACKGROUND & AIMS: We investigated the effects of macrophage migration inhibitory factor (MIF) antibodies in experimental colitis-induced dextran sulfate sodium (DSS) and trinitrobenzenesulfonic acid (TNBS) and examined whether plasma levels of MIF were elevated in patients with inflammatory bowel disease (IBD). METHODS: BALB/c or C57BL/6 mice were fed 4% DSS in their drinking water for up to 7 days with and without administration of an anti-MIF antibody every 2 days. The severity of inflammation in the cecum and colon was assessed by clinical signs and histologic scoring. Tissue levels of MIF, tumor necrosis factor (TNF)-alpha, interferon gamma (IFN-gamma), interleukin (IL)-4, and matrix metalloproteinase (MMP)-13 messenger RNA (mRNA) were measured. The effects of anti-MIF antibody on chronic colitis induced by TNBS was assessed in BALB/c mice. Plasma MIF concentrations were assayed in patients with Crohn's disease, ulcerative colitis, and healthy controls. RESULTS: During DSS-induced colitis, colonic MIF mRNA expression was increased. Clinical signs and histopathologic features were significantly improved in animals given anti-MIF antibody. DSS-induced up-regulation of colonic TNF-alpha and IFN-gamma were significantly suppressed in animals given the anti-MIF antibody. Colonic IL-4 was decreased during DSS but restored to baseline by the anti-MIF antibody. The anti-MIF antibody prevented MMP-13 up-regulation by DSS and ameliorated TNBS colitis. Plasma MIF was elevated in patients with Crohn's disease or ulcerative colitis compared with healthy controls. CONCLUSIONS: We conclude that anti-MIF antibodies reduce the severity of experimental colitis and limit the up-regulation of Th1-type cytokines. Anti-MIF antibodies are of potential therapeutic use in IBD.

Animals↗

Macrophage migration inhibitory factor promotes intestinal tumorigenesis.

BACKGROUND & AIMS: The cytokine macrophage migration inhibitory factor (MIF) is expressed throughout the human gastrointestinal tract. Recently, protumorigenic activity of MIF has been described in several cancer models. Therefore, we investigated the expression and function of MIF during the early stages of intestinal tumorigenesis. METHODS: MIF messenger RNA, protein, and tautomerase activity were measured in normal intestinal mucosa and adenomas from patients with sporadic colorectal adenomas and in the adenomatous polyposis coli (Apc)Min/+ mouse model of intestinal tumorigenesis. MIF function was investigated by using VACO-235 human colorectal adenoma cells in vitro and by testing the effect of genetic deletion of Mif on ApcMin/+ mouse intestinal tumorigenesis. RESULTS: MIF expression and tautomerase activity were increased in human and ApcMin/+ mouse intestinal adenomas compared with adjacent normal mucosa. Up-regulation of MIF occurred mainly in epithelial cells (associated with an increasing grade of dysplasia), but also in stromal plasma cells. Exogenous MIF inhibited apoptosis and promoted anchorage-independent growth of VACO-235 cells (maximal at 100 ng/mL). Homozygous deletion of Mif was associated with a reduction in the number and size of ApcMin/+ mouse adenomas (P = .025 for the difference in large [>7-mm] tumors) and decreased angiogenesis (43% decrease in mean tumor microvessel density), but there was no alteration in epithelial cell apoptosis or proliferation. CONCLUSIONS: MIF expression is increased in sporadic human colorectal adenomas, and exogenous MIF drives tumorigenic behavior of epithelial cells in vitro. Mif also promotes intestinal tumorigenesis (predominantly via angiogenesis) in the ApcMin/+ mouse. Therefore, MIF is a potential colorectal cancer chemoprevention target.

Adenoma↗

Macrophage migration inhibitory factor is induced by thrombin and factor Xa in endothelial cells.

Macrophage migration inhibitory factor (MIF), a proinflammatory cytokine, has been shown to play a role in wound-healing processes. In this study, we investigated whether protease-activated receptor (PAR)-1 and PAR-2 mediated MIF expression in human endothelial cells. Thrombin, factor Xa (FXa), and trypsin induced MIF expression in human dermal microvascular endothelial cells and human umbilical vein endothelial cells, but other proteases, including kallikrein and urokinase, failed to do so. Thrombin-induced MIF mRNA expression was significantly reduced by the thrombin-specific inhibitor hirudin. Thrombin receptor activation peptide-6, a synthetic PAR-1 peptide, induced MIF mRNA expression, suggesting that PAR-1 mediates MIF expression in response to thrombin. The effects of FXa were blocked by antithrombin III, but not by hirudin, indicating that FXa might enhance MIF production directly rather than via thrombin stimulation. The synthetic PAR-2 peptide SLIGRL-NH(2) induced MIF mRNA expression, showing that PAR-2 mediated MIF expression in response to FXa. Concerning the signal transduction, a mitogen-activated protein kinase kinase inhibitor (PD98089) and a nuclear factor (NF)-kappaB inhibitor (SN50) suppressed the up-regulation of MIF mRNA in response to thrombin, FXa, and PAR-2 agonist stimulation, whereas a p38 inhibitor (SB203580) had little effect. These facts indicate that up-regulation of MIF by thrombin or FXa is regulated by p44/p42 mitogen-activated protein kinase-dependent pathways and NF-kappaB-dependent pathways. Moreover, we found that PAR-1 and PAR-2 mRNA expression in endothelial cells was enhanced by MIF. Furthermore, we examined the inflammatory response induced by PAR-1 and PAR-2 agonists injected into the mouse footpad. As shown by footpad thickness, an indicator of inflammation, MIF-deficient mice (C57BL/6) were much less sensitive to either PAR-1 or PAR-2 agonists than wild-type mice. Taken together, these results suggest that MIF contributes to the inflammatory phase of the wound healing process in concert with thrombin and FXa via PAR-1 and PAR-2.

Animals↗