Macrophage Migration Inhibitory Factor mRNA Levels Research Articles

MIF Increases sFLT1 Expression in Early Uncomplicated Pregnancy and Preeclampsia.

Insufficient immune tolerance during pregnancy is associated with pathological conditions such as preeclampsia (PE). Soluble fms-like tyrosine kinase-1 (sFLT1), which exerts a role in the late stage of PE, has shown its beneficial anti-inflammatory effects in inflammation-associated diseases. Macrophage migration inhibitory factor (MIF) was reported to upregulate sFLT1 production in experimental congenital diaphragmatic hernia. However, the placental sFLT1 expression in early uncomplicated pregnancy and whether MIF can regulate sFLT1 expression in uncomplicated and preeclamptic pregnancy are unclear. We collected first-trimester placentas and term placentas from uncomplicated and preeclamptic pregnancies to investigate sFLT1 and MIF expression in vivo. Primary cytotrophoblasts (CTBs) and a human trophoblast cell line (Bewo) were used to study the regulation of MIF on sFLT1 expression in vitro. In placentas from first-trimester pregnancy, we observed a high expression of sFLT1, specifically in extravillous trophoblasts (EVTs) and syncytiotrophoblast (STB) cells. MIF mRNA levels strongly correlated with sFLT1 expression in term placentas from preeclamptic pregnancies. In in vitro experiments, sFLT1 and MIF levels increased significantly in CTBs during their differentiation to EVTs and STBs, and MIF inhibitor (ISO-1) significantly reduced sFLT1 expression in a dose-dependent manner during this process. sFLT1 showed significant upregulation with increasing doses of MIF in Bewo cells. Our results show that sFLT1 is highly expressed at the maternal-fetal interface during early pregnancy and that MIF can increase sFLT1 expression in early uncomplicated pregnancy and PE, which suggests that sFLT1 plays an essential role in the modulation of inflammation in pregnancy.

MIF inhibitor ISO-1 alleviates severe acute pancreatitis-associated acute kidney injury by suppressing the NLRP3 inflammasome signaling pathway

BackgroundAcute kidney injury (AKI) is an important complication of severe acute pancreatitis (SAP) with a poor prognosis. The methyl ester of (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid (ISO-1), an inhibitor of macrophage migration inhibitory factor (MIF), has protective effects against many diseases. Our previous study confirmed MIF inhibition alleviated SAP. Here, we explored the effects of ISO-1 in an experimental mouse model of SAP-associated AKI induced by l-arginine. MethodsMice were randomly divided into four treatment groups (n = 6 each): control (CON), SAP, SAP + ISO-1, and ISO-1. Histopathologic examination was used to observe damage in pancreatic and renal tissues. Biochemical and enzyme-linked immunosorbent assays (ELISA) kits were used to measure the serologic indicators amylase, lipase, creatinine, uric acid, interleukin (IL)-6, and tumor necrosis factor (TNF)-α. Immunohistochemistry was used to detect protein expression of NLRP3, ASC and caspase-1, and the infiltration of myeloperoxidase (MPO)-positive neutrophils in kidney tissue. Western blotting was used to detect NLRP3, ASC and caspase-1 and IL-1β protein expression, and real-time PCR was used to measure MIF, IL-6, TNF-α, IL-1β and IL-18 mRNA levels in kidney tissue. ResultsISO-1 treatment alleviated pathological damage in pancreatic and renal tissues, and reduced the serum levels of amylase, lipase, creatinine, uric acid, IL-6 and TNF-α. ISO-1 also reduced protein expression of NLRP3, ASC, caspase-1 and IL-1β, mRNA expression of MIF, IL-6, TNF-α, IL-1β and IL-18, and the infiltration of MPO-positive neutrophils in kidney tissue. ConclusionISO-1 has a protective effect against experimental SAP-associated AKI. And the mechanism may be associated with ISO-1 inhibiting NLRP3 inflammasome signaling pathway.

Macrophage migration inhibitory factor may play a protective role in osteoarthritis

BackgroundOsteoarthritis (OA) is the most prevalent form of arthritis and the major cause of disability and overall diminution of quality of life in the elderly population. Currently there is no cure for OA, partly due to the large gaps in our understanding of its underlying molecular and cellular mechanisms. Macrophage migration inhibitory factor (MIF) is a procytokine that mediates pleiotropic inflammatory effects in inflammatory diseases such as rheumatoid arthritis (RA) and ankylosing spondylitis (AS). However, data on the role of MIF in OA is limited with conflicting results. We undertook this study to investigate the role of MIF in OA by examining MIF genotype, mRNA expression, and protein levels in the Newfoundland Osteoarthritis Study.MethodsOne hundred nineteen end-stage knee/hip OA patients, 16 RA patients, and 113 healthy controls were included in the study. Two polymorphisms in the MIF gene, rs755622, and -794 CATT5-8, were genotyped using polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) and PCR followed by automated capillary electrophoresis, respectively. MIF mRNA levels in articular cartilage and subchondral bone were measured by quantitative polymerase chain reaction. Plasma concentrations of MIF, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β) were measured by enzyme-linked immunosorbent assay.Resultsrs755622 and -794 CATT5-8 genotypes were not associated with MIF mRNA or protein levels or OA (all p ≥ 0.19). MIF mRNA level in cartilage was lower in OA patients than in controls (p = 0.028) and RA patients (p = 0.004), while the levels in bone were comparable between OA patients and controls (p = 0.165). MIF protein level in plasma was lower in OA patients than in controls (p = 3.01 × 10−10), while the levels of TNF-α, IL-6 and IL-1β in plasma were all significantly higher in OA patients than in controls (all p ≤ 0.0007). Multivariable logistic regression showed lower MIF and higher IL-1β protein levels in plasma were independently associated with OA (OR per SD increase = 0.10 and 8.08; 95% CI = 0.04–0.19 and 4.42–16.82, respectively), but TNF-α and IL-6 became non-significant.ConclusionsReduced MIF mRNA and protein expression in OA patients suggested MIF might have a protective role in OA and could serve as a biomarker to differentiate OA from other joint disorders.

AAV2/9-mediated overexpression of MIF inhibits SOD1 misfolding, delays disease onset, and extends survival in mouse models of ALS

Mutations in superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS), a neurodegenerative disease characterized by the loss of upper and lower motor neurons. Transgenic mice that overexpress mutant SOD1 develop paralysis and accumulate misfolded SOD1 onto the cytoplasmic faces of intracellular organelles, including mitochondria and endoplasmic reticulum (ER). Recently, macrophage migration inhibitory factor (MIF) was shown to directly inhibit mutant SOD1 misfolding and binding to intracellular membranes. In addition, complete elimination of endogenous MIF accelerated disease onset and late disease progression, as well as shortened the lifespan of mutant SOD1 mice with higher amounts of misfolded SOD1 detected within the spinal cord. Based on these findings, we used adeno-associated viral (AAV) vectors to overexpress MIF in the spinal cord of mutant SOD1G93A and loxSOD1G37R mice. Our data show that MIF mRNA and protein levels were increased in the spinal cords of AAV2/9-MIF-injected mice. Furthermore, mutant SOD1G93A and loxSOD1G37R mice injected with AAV2/9-MIF demonstrated a significant delay in disease onset and prolonged survival compared with their AAV2/9-GFP-injected or noninjected littermates. Moreover, these mice accumulated reduced amounts of misfolded SOD1 in their spinal cords, with no observed effect on glial overactivation as a result of MIF up-regulation. Our findings indicate that MIF plays a significant role in SOD1 folding and misfolding mechanisms and strengthen the hypothesis that MIF acts as a chaperone for misfolded SOD1 in vivo and may have further implications regarding the therapeutic potential role of up-regulation of MIF in modulating the specific accumulation of misfolded SOD1.

Targetted inhibition of CD74 attenuates adipose COX-2-MIF-mediated M1 macrophage polarization and retards obesity-related adipose tissue inflammation and insulin resistance.

Adipose tissue (AT) inflammation is crucial to the development of obesity-associated insulin resistance. Our aim was to investigate the contribution of cyclooxygenase-2 (COX-2)/macrophage migration inhibitory factor (MIF)-mediated cross-talk between hypertrophic adipocytes and macrophages to the etiology of AT inflammation and the involvement of CD74 using human SGBS adipocytes, THP-1 macrophages and mice fed a high-fat (HF) diet. The MIF and CD74 mRNA levels in the adipocytes and stromal vascular cells (SVCs) of white fat were highly correlated with body weight (BW), homeostatic model assessment for insulin resistance (HOMA-IR), and adipose macrophage marker expression levels, especially those in SVCs. COX-2 inhibition suppressed the elevation of MIF production in HF white adipocytes as well as palmitate and hypoxic-treated SGBS adipocytes. Treatment of adipocytes transfected with shCOX-2 and siMIF or subjected to MIF depletion in the medium reversed the pro-inflammatory responses in co-incubated THP-1 cells. Inhibition of NF-κB activation reversed the COX2-dependent MIF secretion from treated adipocytes. The targetted inhibition of macrophage CD74 prevented M1 macrophage polarization in the above co-culture model.The COX-2-dependent increases in CD74 gene expression and MIF release in M1-polarized macrophages facilitated the expression of COX-2 and MIF in co-cultured SGBS adipocytes. CD74 shRNA intravenous injection suppressed HF-induced AT M1 macrophage polarization and inflammation as well as insulin resistance in mice. The present study suggested thatCOX-2-mediated MIF secretion through NF-κB activation from hypertrophic and hypoxic adipocytes as well as M1 macrophages might substantially contribute to the phenotypic switch of AT macrophages through CD74 in obesity. Inhibition of CD74 could attenuate AT inflammation and insulin resistance in the development of HF diet-induced obesity.

Significance of the vascular endothelial growth factor and the macrophage migration inhibitory factor in the progression of hepatocellular carcinoma

The aim of the present study was to investigate the expression of vascular endothelial growth factor (VEGF) and macrophage migration inhibitory factor (MIF) in HCC progression and their correlation with clinicopathological factors as well as the relationship between their expression levels. The expression of serum VEGF and MIF was evaluated in 150 patients with HCC and in 30 normal volunteers by enzyme-linked immunosorbent assay (ELISA). VEGF and MIF expression levels were evaluated by immunohistochemistry on tissue microarrays containing 150 HCCs with paired adjacent non-cancer liver tissues. VEGF and MIF mRNA levels were determined by quantitative PCR in another 48 HCCs. The correlation of VEGF and MIF with clinicopathological factors was analyzed in HCC. Serum VEGF and MIF concentrations were higher in HCC patients than the levels in the controls. The expression levels of VEGF and MIF in the HCC tissues were both higher than those in the adjacent non-tumor liver tissues. Overexpression of VEGF and MIF was significantly associated with tumor size (P=0.027 and 0.022, respectively), intrahepatic metastasis (P=0.032 and 0.027, respectively), vascular invasion (P=0.044 and 0.039, respectively) and TNM stage (P=0.028 and 0.013, respectively). Furthermore, VEGF and MIF mRNA levels were higher in HCC compared to levels in the paired non-cancer liver tissues. VEGF and MIF mRNA levels were correlated with tumor stage and metastasis. The expression of VEGF was positively related with MIF expression in HCC. The expression of MIF and VEGF in HCC was markedly positively correlated, which suggests that MIF and VEGF play an important role in the progression of HCC. Both factors may concomitantly accelerate the progression of HCC.

Involvement of Src tyrosine kinase and protein kinase C in the expression of macrophage migration inhibitory factor induced by H2O2 in HL-1 mouse cardiac muscle cells

Macrophage migration inhibitory factor (MIF), a pleiotropic cytokine, plays an important role in the pathogenesis of atrial fibrillation; however, the upstream regulation of MIF in atrial myocytes remains unclear. In the present study, we investigated whether and how MIF is regulated in response to the renin-angiotensin system and oxidative stress in atrium myocytes (HL-1 cells). MIF protein and mRNA levels in HL-1 cells were assayed using immunofluorescence, real-time PCR, and Western blot. The result indicated that MIF was expressed in the cytoplasm of HL-1 cells. Hydrogen peroxide (H2O2), but not angiotensin II, stimulated MIF expression in HL-1 cells. H2O2-induced MIF protein and gene levels increased in a dose-dependent manner and were completely abolished in the presence of catalase. H2O2-induced MIF production was completely inhibited by tyrosine kinase inhibitors genistein and PP1, as well as by protein kinase C (PKC) inhibitor GF109203X, suggesting that redox-sensitive MIF production is mediated through tyrosine kinase and PKC-dependent mechanisms in HL-1 cells. These results suggest that MIF is upregulated by HL-1 cells in response to redox stress, probably by the activation of Src and PKC.

Genomics of corneal wound healing: a review of the literature

Corneal wound healing is a complex process: its mechanisms and the underlying genetic control are not fully understood. It involves the integrated actions of multiple growth factors, cytokines and proteases produced by epithelial cells, stromal keratocytes, inflammatory cells and lacrimal gland cells. Following an epithelial insult, multiple cytokines are released triggering a cascade of events that leads to repair the epithelial defect and remodelling of the stroma to minimize the loss of transparency and function. In this review, we examine the literature surrounding the genomics of corneal wound healing with respect to the following topics: epithelial and stromal wound healing (including inhibition); corneal neovascularisation; the role of corneal nerves in wound healing; the endothelium; the role of aquaporins and aptamers. We also examine the effect of ectasia on corneal wound healing with regard to keratoconus and following corneal surgery. A better understanding of the cellular and molecular changes that occur during repair of corneal wounds will provide the opportunity to design treatments that selectively modulate key phases of the healing process resulting in scars that more closely resemble normal corneal architecture.

Relationship of macrophage migration inhibitory factor levels in PBMCs, lesional skin and serum with disease severity and activity in vitiligo vulgaris

Melanocyte loss in vitiligo vulgaris is believed to be an autoimmune process. Macrophage migration inhibitory factor (MIF) is involved in many autoimmune skin diseases. We determined the possible role of MIF in the pathogenesis of vitiligo vulgaris, and describe the relationship between MIF expressions and disease severity and activity. Serum MIF concentrations and mRNA levels in PBMCs were measured in 44 vitiligo vulgaris patients and 32 normal controls, using ELISA and real-time RT-PCR. Skin biopsies from 15 patients and 6 controls were analyzed by real-time RT-PCR. Values are reported as median (25th-75th percentile). Serum MIF concentrations were significantly increased in patients [35.81 (10.98-43.66) ng/mL] compared to controls [7.69 (6.01-9.03) ng/mL]. MIF mRNA levels were significantly higher in PBMCs from patients [7.17 (3.59-8.87)] than controls [1.67 (1.23-2.42)]. There was also a significant difference in MIF mRNA levels in PBMCs between progressive and stable patients [7.86 (5.85-9.13) vs 4.33 (2.23-8.39)] and in serum MIF concentrations [40.47 (27.71-46.79) vs 26.80 (10.55-36.07) ng/mL]. In addition, the vitiligo area severity index scores of patients correlated positively with changes of both serum MIF concentrations (r = 0.488) and MIF mRNA levels in PBMCs (r = 0.426). MIF mRNA levels were significantly higher in lesional than in normal skin [2.43 (2.13-7.59) vs 1.18 (0.94-1.83)] and in patients in the progressive stage than in the stable stage [7.52 (2.43-8.84) vs 2.13 (1.98-2.64)]. These correlations suggest that MIF participates in the pathogenesis of vitiligo vulgaris and may be useful as an index of disease severity and activity.

A genetic role for macrophage migration inhibitory factor (MIF) in adult-onset Still's disease

IntroductionAdult-onset still's disease (AOSD) is a rare systemic inflammatory disorder in which abnormalities in inflammatory cytokines production appear to play a pathophysiological role. Our previous work has reported increased expression of macrophage migration inhibitory factor (MIF) and revealed its correlation with disease severity and activity in AOSD. A -173 G/C single nucleotide polymorphism (SNP) (rs755622) and a -794 CATT5-8 repeat (rs5844572) in the MIF promoter have been reported. In this study, we sought to explore the relationship between functional MIF promoter polymorphisms and MIF expression in AOSD.Methods100 patients and 200 controls were recruited in the study. A polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was utilized to analyze the -173 G/C SNP (rs755622) and PCR-based size discrimination assay was applied to detect the -794 CATT5-8 repeat (rs5844572) in the MIF promoter. Plasma MIF levels were measured by ELISA. MIF mRNA levels were quantified by real-time reverse transcription (RT)-PCR. Bisulfate genomic sequencing was employed to evaluate DNA methylation status within the MIF promoter.ResultsWe identified that the frequencies of MIF -794 CATT5 (P = 0.001) allele and the expression of MIF (P <0.001) were increased in patients compared to healthy controls. Plasma levels of MIF in patients with CC genotype were higher than those of patients with GC or GG genotypes (P = 0.05). In patients with established AOSD, a higher frequency of -794 CATT7 containing MIF genotypes was observed in those with liver dysfunction (P = 0.009). Haplotype analysis revealed a higher representation of the MIF haplotype defined by -173*C/-794 CATT5 (C5) in AOSD patients (P = 0.001).ConclusionFunctional promoter polymorphisms in the MIF gene influence plasma MIF levels in AOSD and may contribute to disease susceptibility or clinical presentation of AOSD.

Release of macrophage migration inhibitory factor by neuroendocrine-differentiated LNCaP cells sustains the proliferation and survival of prostate cancer cells

The acquisition of neuroendocrine (NE) characteristics by prostate cancer (PCa) cells is closely related to tumour progression and hormone resistance. The mechanisms by which NE cells influence PCa growth and progression are not fully understood. Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine involved in oncogenic processes, and MIF serum levels correlate with aggressiveness of PCa. Here, we investigated the regulation and the functional consequences of MIF expression during NE transdifferentiation of PCa cells. NE differentiation (NED) of LNCaP cells, initiated either by increasing intracellular levels of cAMP or by culturing cells in an androgen-depleted medium, was associated with markedly increased MIF release. Yet, intracellular MIF protein and mRNA levels and MIF gene promoter activity decreased during NED of LNCaP cells, suggesting that NED favours MIF release despite decreasing MIF synthesis. Adenoviral-mediated forced MIF expression in NE-differentiated LNCaP cells increased cell proliferation without affecting the expression of NE markers. Addition of exogenous recombinant MIF to LNCaP and PC-3 cells stimulated the AKT and ERK1/2 signalling pathways, the expression of genes involved in PCa, as well as proliferation and resistance to paclitaxel and thapsigargin-induced apoptosis. Altogether, these data provide evidence that increased MIF release during NED in PCa may facilitate cancer progression or recurrence, especially following androgen deprivation. Thus, MIF could represent an attractive target for PCa therapy.

Effects of overexpression of macrophage migration inhibitory factor on bone morphogenetic protein2 and vascular endothelial growth factor in osteoblasts

Objective To discuss the overexpression of macrophage migration inhibitory factor (MIF) on bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) in osteoblasts.Methods Human osteoblasts were isolated from 5 patients,and then pcDNA3.0-MIF was constructed and transfected into osteoblasts.The effect of MIF overexpression on BMP-2 and VEGF in osteoblasts was detected.Results MIF overexpression was verified (P ＜0.05).MIF,and BMP-2 and VEGF mRNA and protein levels were higher in transfected cells than in control cells (P ＜ 0.05).Conclusion Overexpression of MIF up-regulated the BMP-2 and VEGF in osteoblasts. Key words: Osteoblast cells; Macrophage migration inhibitory factor; Bone morphogenetic protein 2; Vascular endothelial growth factor

Differential Effects of Trypanosoma brucei gambiense and Trypanosoma brucei brucei on Rat Macrophages

Mammalian immune responses to Trypanosoma brucei infection are important to control of the disease. In rats infected with T. brucei gambiense (Wellcome strain; WS) or T. brucei brucei (interleukin-tat 1.4 strain [ILS]), a marked increase in the number of macrophages in the spleen can be observed. However, the functional repercussions related to this expansion are not known. To help uncover the functional significance of macrophages in the context of trypanosome infection, we determined the mRNA levels of genes associated with an increase in macrophage number or macrophage function in WS- and ILS-infected rats and in cultured cells. Specifically, we assayed mRNA levels for macrophage colony stimulating factor (M-CSF), granulocyte macrophage colony stimulating factor (GM-CSF), and macrophage migration inhibitory factor (MIF). Upregulation of GM-CSF and MIF mRNA levels was robust in comparison with changes in M-CSF levels in ILS-infected rats. By contrast, upregulation of M-CSF was more robust in WS-infected rats. The phagocytic activity in macrophages harvested from ILS-infected rat spleens, but not WS-infected spleens, was higher than that in macrophages from uninfected rats. These results suggest that macrophages of WS-infected rats change to an immunosuppressive type. However, when WS or ILS is cocultured with spleen macrophages or HS-P cells, a cell line of rat macrophage origin, M-CSF is upregulated relative to GM-CSF and MIF in both cell types. Anemia occurs in ILS-, but not WS-infected, rats. Treatment of spleen macrophages or HS-P cells cocultured with ILS with cobalt chloride, which mimics the effects of anemia-induced hypoxia, led to downregulation of M-CSF mRNA levels, upregulation of GM-CSF and MIF, and an increase in phagocytic activity. However, the effect of cobalt chloride on spleen macrophages and HS-P cells cocultured with WS was restricted. These results suggest that anemia-induced hypoxia in ILS-infected rats stimulates the immune system and activates macrophages.

Expression of macrophage migration inhibitory factor in human endometriosis: Relation to disease stage, menstrual cycle and infertility

The aim of the present study was to compare the expression of macrophage migration inhibitory factor (MIF) in eutopic and ectopic endometria of women with endometriosis and eutopic endometria of women without endometriosis, and to investigate whether such an expression varies according to disease stage, menstrual cycle and infertility status. Forty patients with endometriosis and 15 control women were recruited for the study. Following isolation of total RNA from endometria and reverse transcription, cDNA samples were amplified to quantify the level of MIF expression by real-time fluorescent quantitative polymerase chain reaction. All of the endometriosis tissue and normal endometrium specimens were analyzed using immunohistochemistry. The levels of MIF in eutopic and ectopic endometria in endometriosis patients were significantly higher than in normal eutopic endometria (P < 0.01). Further, when comparing MIF in eutopic endometria (separated by phases) between the endometriosis and control groups, MIF was higher in the former group, both in the proliferative and secretory phases (P < 0.05). In addition, the MIF mRNA level was cycle phase-dependent and increased in the proliferative phase, both in women with endometriosis and the control women, compared with the level in the secretory phase (P < 0.05). There was no significant association between MIF expression and American Fertility Society staging of endometriosis (P > 0.05). However, MIF levels were obviously elevated in sterile women in the endometriosis group compared with women in the endometriosis group who were not sterile (P < 0.05). The expression of MIF was increased significantly in the eutopic and ectopic endometrial tissue of women with endometriosis, and this factor may play a possible role in endometriosis-associated infertility.

Molecular characterization and functional analysis of porcine macrophage migration inhibitory factor (MIF) gene

Originally identified as a cytokine that inhibits the migration of macrophages from capillaries, MIF has now emerged to be a multifunctional factor involved in immune response, glucose and lipid metabolism. We report here the molecular characterization of porcine MIF gene, which resides on chromosome 14q21.3 and encodes 114 amino acids. Porcine MIF mRNA was found to be highly expressed in stomach, to a lesser extent in spleen, and at the lowest levels in skeletal muscle and heart. To gain further insight into the functional regulation of MIF, we cloned the porcine MIF promoter and verified its functionality using luciferase reporter assay. In NIH 3T3 cells, the endogenous MIF mRNA level was up-regulated by rosiglitazone treatment in a dose-dependent manner, which was accompanied by a concurrent increase in peroxisome proliferator-activated receptor (PPAR)gamma2 transcription. Over-expression of porcine PPARgamma2 in NIH 3T3 cells could also up-regulate the transcription of MIF in the absence of rosiglitazone treatment. These observations are consistent with the bioinformatic analysis that reveals two potential PPAR binding sites within the MIF promoter. Additionally, the over-expression of resistin, a factor considered to be a link between inflammation and metabolic signals, could remarkably down-regulate the transcription of MIF in NIH 3T3 cells. Taken together, we proposed that the transcription of MIF is induced by activation of PPARgamma2 and inhibited by excessive resistin.

Role of macrophage migration inhibitory factor in influenza H5N1 virus pneumonia

The severe and often fatal disease in humans and birds caused by H5N1 influenza viruses has been attributed to aberrant pulmonary inflammatory responses. We investigated the role of macrophage migration inhibitory factor (MIF), a proinflammatory cytokine and a pivotal regulator of innate immunity, in H5N1 influenza virus pneumonia in murine model. We found increased MIF mRNA levels in the lungs and MIF protein levels in the serum of infected mice. Although the inhibition of MIF action by isoxazolone-1 (ISO-1) did not render mice more resistant to the lethality of infection, it caused a significant reduction in pulmonary inflammatory cytokines interleukin-1 beta (IL-1beta), IL-6 and tumor necrosis factor alpha (TNF-alphalfa) and chemokine interferon-inducible protein-10 (IP-10). These results indicate the involvement of MIF in inflammatory responses to H5N1 influenza virus infections by induction of pulmonary inflammatory cytokines and chemokines, and suggest that pharmacotherapeutic approaches targeting MIF may hold promise for the treatment of H5N1 influenza virus pneumonia.

Redox regulation of macrophage migration inhibitory factor expression in rat neurons

Macrophage migration inhibitory factor (MIF) expression is induced by angiotensin II (Ang II) in normal rat neurons and serves a negative regulatory role by blunting the chronotropic actions of this peptide. The aim here was to determine whether hydrogen peroxide (H 2O 2), a reactive oxygen species (ROS) that is a key intracellular mediator of the neuronal actions of Ang II, is a trigger for MIF production in neurons. Thus, we tested the effects of H 2O 2 on MIF expression in primary neuronal cultures from newborn normotensive (Wistar Kyoto [WKY] or Sprague–Dawley [SD]) rat brain, cells that respond to Ang II by increasing MIF levels. Treatment of WKY or SD rat neuronal cultures with a non-cytotoxic concentration of H 2O 2 elicited a significant, time-dependent increase in MIF mRNA and protein levels. Glucose oxidase, which produces H 2O 2 via oxidation of glucose in the cell-culture medium, elicited a similar increase in neuronal MIF mRNA levels. The stimulatory action of H 2O 2 was not apparent in neuronal cultures from spontaneously hypertensive rats (SHR), cells that fail to express increased MIF in response to Ang II. Finally, preincubation of SD rat cultures with either polyethylene glycol-catalase or actinomycin D abolished the H 2O 2-induced increase in MIF, suggesting that this ROS is acting intracellularly to increase transcription of the MIF gene. These results suggest the presence of a redox regulatory mechanism for induction of MIF in normotensive rat neurons.

The expression of MIF in colon tissues of rats with TNBS-induced colitis

Objective To observe the expression of macrophage migration inhibitory factor (MIF) in colon tissues of rats with 2,4, 6-trinitrobenzene sulfonic acid (TNBS) induced colitis and the relationship between MIF and the severity of the colitis. Methods 24 Spra-gue-Dawley rats were randomly divided into three groups: normal group, model group Ⅰ and model group Ⅱ. Rat colitis model was induced by 2,4,6-trinitrobenzene sulfonic acid (TNBS), and disease activity index (DAI) was calculated every day. The myeloperoxidase (MPO) ac-tivity was detected by biochemistry, the expression of MIF in colon tissue was detected by semi-quantitative reverse transcriptional chain reac-tive (RT-PCR). Results In normal group, DAI, MPO activity and MIF mRNA level were 0.51±0. 28,0. 38±0. 18,0. 11±0. 03, while in model group Ⅰ were 5.04±0.73,1.68±0. 45,0. 65±0.04 and in model group Ⅱ were 8. 13±0.71,2. 70±0. 35,0. 81±0. 05. Com-pared with normal control, the expression of MIF mRNA significantly increased (P<0.05), MPO activity and DAI also significantly in-creased(P<0.05)in model group, especially in model group Ⅱ. Conclusion The expression of MIF increased in experimental colitis, and there was a positive relation between MIF expression and the severity of colitis, which suggested that MIF may be related to the pathogen-esis of TNBS-induced colitis. Key words: Macrophage migration-inhibitory factors/BI; Colitis ; Trinitrobenzensulfonic acid/AE

Detection of a positive feedback loop between macrophage migration inhibitory factor (MIF) and estrogen in endometriosis

OBJECTIVE: To determine the interaction between MIF and estradiol (E2) in human ectopic endometrial cells. DESIGN: Primary cultures of ectopic endometrial cells exposed to E2 or to MIF and assessment of MIF and aromatase regulation. MATERIALS AND METHODS: Endometriotic stromal cells were isolated from human endometriotic lesions. Cells were then stimulated with E2 (10-9 M and 10-8 M) or MIF (10 and 50 ng/mL) for different periods of time (0-48 h). MIF secretion and mRNA levels were measured by ELISA and real time RT-PCR respectively. The transcriptional activity of MIF gene was analyzed by transfection with different MIF promoter-luciferase reporter constructs. The presence of estrogen receptors ERαand ERβ was assessed by immunocytofluorescence and the role of these receptors was evaluated by transfection with expression vectors. Aromatase protein was analyzed by immunocytofluorescence and western blot, and mRNA levels were assessed by real-time RT-PCR. An unpaired t test and one-way ANOVA followed by the Dunnett test were performed. RESULTS: Our study showed that E2 significantly induced MIF protein and mRNA expression in endometriotic stromal cells in a dose- and time-dependent manner. Treatment with Fulvestrant (a pure estrogen receptor antagonist) suppressed the ability of E2 to induce MIF protein secretion and mRNA synthesis. The MIF promoter activity was significantly stimulated with E2 compared to control. Transfection of endometriotic stromal cells with estrogen receptors ERαand ERβ resulted in a statistically significant increase of the E2-induced activation of the MIF protein and mRNA levels compared to culture medium without stimulation. However, when we compared the responses to cells transfected with control vector, the only statistically significant difference has been observed with ERβ. Moreover, MIF significantly stimulated aromatase protein and mRNA expression. CONCLUSIONS: The present study revealed the existence of a positive feedback loop operating locally in ectopic endometrial implants by which estrogen acts directly on ectopic endometrial cells to upregulate the expression of MIF, which, in turn, displays the capability of inducing the expression of aromatase, the key and rate-limiting enzyme for estrogen synthesis. Such immuno-endocrine interplay may have a considerable impact on endometriosis development.

The microsatellite, macrophage migration inhibitory factor ‐794, may influence gene expression in human mononuclear cells stimulated with E. coli or S. pneumoniae

Polymorphisms within the gene encoding macrophage migration inhibitory factor (MIF) have been associated with susceptibility to inflammatory diseases such as rheumatoid arthritis and increased risk of developing sepsis. We investigated the effects of the MIF-173G>C polymorphism and the MIF-794 CATT microsatellite on MIF expression. These are in moderate linkage disequilibrium. Mononuclear cells from healthy donors were stimulated with bacterial pathogens associated with sepsis (Streptococcus pneumoniae or Escherichia coli ). MIF mRNA and protein levels were measured by real-time polymerase chain reaction and ELISA, respectively. Carriage of the C allele of MIF-173G>C or the 7 CATT repeat of the MIF-794 microsatellite correlated with lower basal and stimulated MIF mRNA levels. However, levels of intracellular and extracellular MIF protein were similar. This discordance between effects on MIF mRNA and protein was not explained by differential effects of genotype on stability of MIF mRNA (detected by actinomycin D mRNA chase). Gel shift assays revealed no differences in the profile of nuclear proteins from mononuclear cells bound by the G and C alleles of MIF-173G>C, but alleles at the microsatellite marker showed differential binding. Our data suggest that the MIF-794 CATT microsatellite influences transcription by differential binding of nuclear transcription factors. This may impact on inflammatory processes.