Induction of T-Kininogen and Tumor Necrosis Factor-α by Macrophage Migration Inhibitory Factorin vivo

Administration of lipopolysaccharide (LPS) induces inflammation and tissue injuries that occasionally results in disseminated intravascular coagulation (DIC). This process is believed to be mediated by vasoactive molecules such as kinins and leads to endothelial damage and obstruction of the microcirculation. In this study, we evaluated the involvement of T-kininogen and macrophage migration inhibitory factor (MIF) in endotoxin-induced systemic inflammation. T-Kininogen is a protein unique to the rat and known as an acute-phase protein in response to endotoxins. Similarly, MIF functions as a proinflammatory cytokine and glucocorticoid-induced immunoregulator. First, we examined the effects of anti-MIF antibody on Wistar King male rats (ca 400 g) treated with intraperitoneal injection of LPS. At 6 hours after LPS injection (5 mg/kg), the platelet counts had decreased from 85 +/- 12.8 (x 10(4)/microL) to 8.8 +/- 2.6 (x 10(4)/microL). We treated these rats with the anti-rat MIF antibody (5 mg gamma G immunoglobulin [IgG] fraction/kg) 2 hours prior to LPS injection. This treatment prevented the decrease in platelet counts (45.6 +/- 5.6 [x 10(4)/microL]). Next, we examined the potential of MIF for production of T-kininogen. Intraperitoneal injection of rat MIF significantly upregulated the serum content of T-kininogen at the dose of 500 microg MIF/head. These results imply that MIF and T-kininogen might function in concert in the event of endotoxin-induced inflammation.

α-Thrombin Stimulates Expression of Macrophage Migration Inhibitory Factor in Skin Fibroblasts

Macrophage migration inhibitory factor (MIF) is induced by various stimuli such as wounds and infection and regulates inflammatory and immunological responses. To date, we have found increased expression of MIF during the wound healing process in rat skin. Immunohistochemical analysis demonstrated enhanced expression of MIF in wound skin lesions. On the other hand, alpha-thrombin, a multifunctional serine protease, plays an important role in wound healing with regard to induction of inflammatory cytokines such as interleukin-6 (IL-6). Accordingly, we examined the effect of alpha-thrombin on MIF production in human skin fibroblasts. Alpha-thrombin significantly stimulated MIF secretion into culture medium of fibroblasts quantitated by an enzyme-linked immunosorbent assay (ELISA). Consistent with this, we observed the upregulation of MIF mRNA in response to alpha-thrombin by Northern blot analysis. Taken together, these results suggest that MIF produced by fibroblasts in response to alpha-thrombin plays an important regulatory role in wound repair.

Role for macrophage migration inhibitory factor in asthma

Macrophage migration inhibitory factor (MIF) is an immunologic regulator that is expressed in inflammatory and autoimmune disorders. We investigated MIF's role in asthma using genetic approaches in a mouse model and in a cohort of asthma patients. Mice genetically deficient in MIF that were primed and aerosol-challenged with ovalbumin showed less pulmonary inflammation and lower airway hyperresponsiveness than genetically matched, wild-type controls. MIF deficiency also resulted in lower titers of specific IgE, IgG(1), and IgG(2a), and decreased pulmonary, T(H)2 cytokine levels. IL-5 concentrations were lower and corresponded to decreased eosinophil numbers in bronchoalveolar lavage fluid. T cell studies also showed a lower level of antigen-specific responses in MIF-KO versus wild-type mice. In an analysis of 151 white patients with mild, moderate, or severe asthma (Global Initiative for Asthma criteria), a significant association was found between mild asthma and the low-expression, 5-CATT MIF allele. Pharmacologic inhibition of MIF may be beneficial and could be guided by the MIF genotype of affected individuals.

Aqueous levels of macrophage migration inhibitory factor and monocyte chemotactic protein-1 in patients with diabetic retinopathy

AIMS

To investigate the relationship of aqueous macrophage migration inhibitory factor (MIF) and monocyte chemotactic protein-1 (MCP-1) levels with the clinical stage of diabetic retinopathy.

METHODS

We assayed MIF and MCP-1 levels in aqueous humour samples obtained from 40 diabetic patients (49 eyes) and 24 non-diabetic patients (31 eyes) using enzyme-linked immunosorbent assay. According to the clinical stage of diabetic retinopathy, the diabetic patients were classified into non-diabetic retinopathy (11 eyes), non-proliferative diabetic retinopathy (14 eyes) and proliferative diabetic retinopathy (24 eyes).

RESULTS

The aqueous levels of MIF (mean +/- sd) were 6.34 +/- 4.53 ng/ml in proliferative diabetic retinopathy, 3.22 +/- 1.71 ng/ml in non proliferative diabetic retinopathy, 1.25 +/- 0.96 ng/ml in non-diabetic retinopathy and 1.07 +/- 0.94 ng/ml in non-diabetic patients. Significant differences were found among these four groups (P < 0.0001). Aqueous MCP-1 levels were 1668.6 +/- 1442.3 pg/ml in proliferative diabetic retinopathy, 1528.6 +/- 1994.6 pg/ml in non-proliferative diabetic retinopathy, 690.2 +/- 402.1 pg/ml in non-diabetic retinopathy and 622.7 +/- 245.3 pg/ml in non-diabetic patients. Significant differences were also found among these four groups (P < 0.0001). After correcting for total aqueous protein, the ratios of MIF and MCP-1 to total protein remained significantly correlated with the clinical stage of diabetic retinopathy (P < 0.0001, P = 0.0004, respectively). The ratios of MIF to total protein significantly correlated with the ratios of MCP-1 to total protein in diabetic patients (r = 0.680, P < 0.0001).

CONCLUSIONS

Aqueous MIF levels significantly correlated with aqueous MCP-1 levels and the clinical stage of diabetic retinopathy. The results suggest that MIF has a co-operative role with MCP-1 in the progression of diabetic retinopathy.

Macrophage migration inhibitory factor as a redox-sensitive cytokine in cardiac myocytes

OBJECTIVE

Macrophage migration inhibitory factor (MIF), which plays a pivotal role in the control of inflammatory responses, was first characterized as a T-cell cytokine, but later was also found as a pituitary peptide released in response to infection and stress. However, MIF's role and expression in the myocardium has never been reported. The goal of this study is to examine MIF in the myocardium.

METHODS AND RESULTS

MIF protein and mRNA levels were assayed using enzyme-linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR), respectively. Increased MIF concentrations were detected in the sera of patients with acute myocardial infarction (AMI). In cultured rat cardiac myocytes, significant amounts of MIF were produced in response to hypoxia and hydrogen peroxide (H(2)O(2)), but not to angiotensin II, endothelin-1, interleukin-1beta (IL-1beta) or tumor necrosis factor alpha (TNFalpha). H(2)O(2)-induced MIF production increased in a time- and dose-dependent manner and was completely abolished in the presence of catalase. H(2)O(2) also induced MIF mRNA expression. The H(2)O(2)-induced MIF production was completely inhibited by the protein kinase C (PKC) inhibitor GF109203X, partially inhibited by the tyrosine kinase inhibitor herbimycin A, and uninhibited by calcium chelation or phorbol ester-sensitive PKC down-regulation. This suggests that H(2)O(2)-induced MIF production is mediated by an atypical PKC isoform. DNA microarray analysis revealed that 52 genes were preferentially expressed in response to MIF. Of these, the MIF-induced expression of both glutathione S-transferase (GST) and lipopolysaccharide-induced CXC chemokine (LIX) mRNAs was confirmed using RT-PCR analysis.

CONCLUSION

The present results suggest that MIF is expressed by the myocardium in response to redox stress and may play a role in the pathogenesis of myocardial ischemia.

Monocyte chemotactic protein-1 in the vitreous of patients with proliferative diabetic retinopathy

PURPOSE

To investigate the correlation between monocyte chemotactic protein-1 (MCP-1) levels in the vitreous and clinical findings in eyes with proliferative diabetic retinopathy (PDR).

METHODS

We assayed MCP-1 levels by ELISA in vitreous samples of 88 consecutive patients with PDR (52 eyes) and macular holes or idiopathic epimacular membrane (controls, 36 eyes).

RESULTS

The level of MCP-1 in the vitreous was 2,097.5 +/- 1,099.4 pg/ml (mean +/- SD) in PDR, and 504.3 +/- 405.6 pg/ml in the controls. In PDR eyes, multivariate regression analysis revealed a significant association between MCP-1 levels in the vitreous and the degree of proliferative membrane, and a significant negative association between MCP-1 levels and the extent of preoperative retinal photocoagulation.

CONCLUSION

The results suggest that MCP-1 may play a role in the development of the proliferative phase of PDR.

High-dose corticosteroid administration induces increase of serum macrophage migration inhibitory factor in patients with Vogt-Koyanagi-Harada's disease

To investigate the influence of corticosteroid administration on the serum level of macrophage migration inhibitory factor (MIF), sera obtained from 9 patients with Vogt-Koyanagi-Harada's disease who had been treated with high-dose corticosteroid were analyzed. The serum MIF levels of most patients were prominently increased on day 7 and/or day 14 after corticosteroid treatment. No TNF-alpha was detected in the sera. The average serum MIF level of nine patients at the highest stages after corticosteroid administration was significantly higher than that before the corticosteroid treatment. It seems that MIF is a unique cytokine and acts together with corticosteroid to regulate inflammation and immunity.

Increase of macrophage migration inhibitory factor in sera of patients with iridocyclitis

AIMS

To determine whether macrophage migration inhibitory factor (MIF) levels were increased in sera of the patients with iridocyclitis.

METHODS

Sera were obtained from 41 patients with acute iridocyclitis, 13 patients with chronic iridocyclitis, and 44 healthy control subjects. MIF levels were determined by a human MIF ELISA.

RESULTS

The average levels of MIF in the sera of patients with both acute and chronic iridocyclitis were significantly higher than that of healthy subjects.

CONCLUSION

Uveitis induces the elevation of serum MIF, which may affect various inflammatory symptoms in uveitis.

Macrophage migration inhibitory factor levels in the vitreous of patients with proliferative diabetic retinopathy

AIMS

To assess the potential role of macrophage migration inhibitory factor (MIF) in the pathogenesis of proliferative diabetic retinopathy (PDR).

METHODS

MIF levels were assayed in the vitreous and paired serum samples of 73 consecutive patients with PDR (32 eyes) and macular hole or idiopathic epiretinal membrane (controls, 41 eyes). An enzyme linked immunosorbent assay technique was used to determine the concentrations of MIF.

RESULTS

The median vitreous level of MIF was 11.93 ng/ml (range 4.16-103.85) in the patients with PDR, and 1.79 ng/ml (undetectable-8.93) in the controls. Vitreous levels in eyes with PDR were significantly greater than those in the controls (p<0.0001). Vitreous levels were significantly higher than serum levels in eyes with PDR (p=0.0026). MIF levels were significantly higher in the vitreous of PDR patients with severe fibrous proliferation than in those with slight proliferation (p<0.05).

CONCLUSION

The results indicate increased levels of MIF in the vitreous of patients with PDR and a significant association between MIF levels and grades of fibrous proliferation, suggesting the possibility that MIF may play a part in the development of the proliferative phase of PDR.

Hepatocyte growth factor levels in the vitreous of patients with proliferative vitreoretinopathy

PURPOSE

To determine whether the hepatocyte growth factor is increased in the vitreous of patients with proliferative vitreoretinopathy.

METHODS

We assayed hepatocyte growth factor levels by enzyme-linked immunosorbent assay (ELISA) in vitreous samples from 65 consecutive eyes (65 patients) with proliferative vitreoretinopathy (23 eyes), rhegmatogenous retinal detachment (22 eyes), and macular hole or idiopathic epiretinal membrane (control subjects, 20 eyes) having undergone pars plana vitrectomy.

RESULTS

Vitreous levels of hepatocyte growth factor were 3.94 +/- 2.29 (mean +/- SD) ng/ml in proliferative vitreoretinopathy, 2.02 +/- 0.84 ng/ml in rhegmatogenous retinal detachment, and 2.16 +/- 1.39 ng/ml in the control subjects. The vitreous levels in proliferative vitreoretinopathy were much greater than levels in rhegmatogenous retinal detachment (P =.0002) and in the control subjects (P =.0007). In proliferative vitreoretinopathy, there was a tendency toward higher levels in eyes with grade D by the Retina Society terminology.

CONCLUSION

The results suggest the possibility that hepatocyte growth factor may play a role in the pathogenesis of proliferative vitreoretinopathy.

Quantitation of macrophage migration inhibitory factor (MIF) using the one-step sandwich enzyme immunosorbent assay: elevated serum MIF concentrations in patients with autoimmune diseases and identification of MIF in erythrocytes

We raised monoclonal antibodies against human macrophage migration inhibitory factor (MIF), and developed a one-step sandwich enzyme-linked immunosorbent assay (ELISA) method highly specific for human MIF. The ELISA system utilizes a solid phase monoclonal antibody as a capture antibody and a horseradish peroxidase-conjugated monoclonal antibody as a detector antibody. We used this ELISA method to evaluate the serum level of MIF in 240 healthy volunteers (140 males and 100 females). We found no significant difference in MIF concentration with respect to age. A significant difference was found with respect to sex, with the mean value (+/- SD) for male subjects of 5.3+/-2.3, and that for female subjects of 4.6+/-2.3 ng/ml (p<0.05). We next measured the serum MIF contents of patients with autoimmune diseases, and found that MIF levels were significantly elevated in patients with systemic lupus erythematosus and rheumatoid arthritis, 20.0+/-11.0 ng/ml and 21. 7+/-11.2 ng/ml, respectively. Using anti-MIF antibody-immobilized sepharose column chromatography, we discovered for the first time that MIF was present in erythrocytes. Taken together these results suggest that MIF plays a major role in autoimmune diseases and, moreover, potentially induces various patho-logical outcomes in cases of hemolytic disorders.

Macrophage migration inhibitory factor up-regulates expression of matrix metalloproteinases in synovial fibroblasts of rheumatoid arthritis

Neutral matrix metalloproteinases (MMPs) are responsible for the pathological features of rheumatoid arthritis (RA) such as degradation of cartilage. We herein show the up-regulation of MMP-1 (interstitial collagenase) and MMP-3 (stromelysin) mRNAs of cultured synovial fibroblasts retrieved from rheumatoid arthritis (RA) patients in response to macrophage migration inhibitory factor (MIF). The elevation of MMP-1 and MMP-3 mRNA was dose-dependent and started at 6 h post-stimulation by MIF, reached the maximum level at 24 h, and was sustained at least up to 36 h. Interleukin (IL)-1beta mRNA was also up-regulated by MIF. These events were preceded by up-regulation of c-jun and c-fos mRNA. Tissue inhibitor of metalloproteinase (TIMP)-1, a common inhibitor of these proteases, was slightly up-regulated by MIF. Similarly, mRNA up-regulation of MMP-1 and MMP-3 was observed in the synovial fibroblasts of patients with osteoarthritis. However, their expression levels were much lower than those of RA synovial fibroblasts. The mRNA up-regulation by MIF was inhibited by the tyrosine kinase inhibitors genestein and herbimycin A, as well as the protein kinase C inhibitors staurosporine and H-7. On the other hand, the inhibition was not seen after the addition of the cyclic AMP-dependent kinase inhibitor, H-8. The mRNA up-regulation of MMPs was also inhibited by curcumin, an inhibitor of transcription factor AP-1, whereas interleukin-1 receptor antagonist, an IL-1 receptor antagonist, failed to inhibit the mRNA up-regulation. Considering these results, it is suggested that 1) MIF plays an important role in the tissue destruction of rheumatoid joints via induction of the proteinases, and 2) MIF up-regulates MMP-1 and MMP-3 via tyrosine kinase-, protein kinase C-, and AP-1- dependent pathways, bypassing IL-1beta signal transduction.

Macrophage migration inhibitory factor levels in the vitreous of patients with proliferative vitreoretinopathy

PURPOSE

To assess the potential role of macrophage migration inhibitory factor (MIF) in the pathogenesis of proliferative vitreoretinopathy.

METHODS

We assayed MIF levels in vitreous and paired serum samples of 74 consecutive patients with proliferative vitreoretinopathy (26 eyes), rhegmatogenous retinal detachment (22 eyes), and macular hole or idiopathic epiretinal membrane (control, 26 eyes) by enzyme-linked immunosorbent assay.

RESULTS

Vitreous levels of MIF were 51.33 +/- 49.21 ng/ml (mean +/- SD) in proliferative vitreoretinopathy, 19.11 +/- 16.13 ng/ml in rhegmatogenous retinal detachment, and 2.98 +/- 2.55 ng/ml in the controls. The vitreous levels in eyes with proliferative vitreoretinopathy were significantly higher than levels in eyes with rhegmatogenous retinal detachment (P = .0005) and in the control subjects (P < .0001). The vitreous levels were significantly higher than the serum levels in proliferative vitreoretinopathy (P < .0001) and rhegmatogenous retinal detachment (P = .0019), respectively.

CONCLUSIONS

The results suggest that MIF may be involved in the pathogenesis of proliferative vitreoretinopathy.

High expression of macrophage migration inhibitory factor in the synovial tissues of rheumatoid joints

Macrophage migration inhibitory factor (MIF) plays an important role in inflammation and immunity via autocrine/paracrine and endocrine routes. We examined the presence of MIF in the synovial fluids of rheumatoid arthritis (RA) patients. The content of MIF in the synovial fluid was quantitated by enzyme-linked immunosorbent assay which revealed that the concentration of MIF for RA patients was 85. 7+/-35.2 ng/ml (mean+/-SD) (n=25). In comparison, the concentrations for osteoarthritis patients and normal volunteers were 19.5+/-5.3 ng/ml (n=12) and 10.4+/-1.1 ng/ml (n=5), respectively. The expression of MIF mRNA and presence of MIF protein in the synovial tissues of RA were demonstrated by Northern blot and Western blot analyses, respectively. Immunohistochemical analysis revealed that positive staining was largely observed in the cytoplasm of infiltrating T lymphocytes, which might be the major source of MIF detected in the synovial fluids. The pathophysiological role of MIF in RA remains to be elucidated; however, the present results for the first time suggest the possibility that MIF is involved in the potentiation of inflammatory and immunological responses in rheumatoid joints.

Identification of macrophage migration inhibitory factor (MIF) in human vascular endothelial cells and its induction by lipopolysaccharide

Cytokines play an important role in inflammation and immunity. In this study, the authors examined expression of macrophage migration inhibitory factor (MIF) in vascular endothelial cells, using human umbilical vein endothelial cells (HUVEC), by reverse transcription-polymerase chain reaction (RT-PCR)/Southern blot, Western blot analysis, and immunohistochemistry. The RT-PCR/Southern blot showed that MIF mRNA was exceedingly upregulated by the stimulation of lipopolysaccharide (LPS) and reached the maximum 12 h after the stimulation. At the range of 10 pg/ml to 10 ng/ml of LPS, the MIF mRNA expression was induced in a dose-dependent manner, but drastically decreased at doses of more than 100 ng/ml. Western blot analysis and immunohistochemistry using an anti-human MIF antibody revealed the presence of MIF protein in cytoplasm of the unstimulated cells. The precise pathophysiological role of MIF in HUVEC has not been fully understood; however, the upregulation of MIF mRNA expression in vascular endothelial cells by LPS stimulation suggests the possibility that the cytokine plays an important role in systemic inflammatory events such as endotoxaemia.

Macrophage migration inhibitory factor is an essential immunoregulatory cytokine in atopic dermatitis

Macrophage migration inhibitory factor (MIF) is one of the immunoregulatory cytokines involved in T-cell activation and delayed-type hypersensitivity. To elucidate involvement of this cytokine in the pathogenesis of atopic dermatitis (AD), we examined serum MIF concentrations of patients with AD and non-atopic normal healthy individuals. The mean serum MIF concentration of the AD patients (n = 36) was 36.4 +/- 3.7 ng/ml (mean +/- SEM), whereas that of the non-atopic dermatitis patients (n = 17) or healthy individuals (n = 61) were 13.1 +/- 1.8 or 6.5 +/- 0.45 ng/ml, respectively. Accordingly, immunohistochemistry of the inflammatory skin lesion of an AD patient demonstrated that MIF protein was diffusely expressed throughout the whole epidermal layer. After 4-week steroid ointment treatment, the MIF concentration decreased as clinical symptoms improved. The serum level of TNF-alpha was also decreased in parallel with that of MIF. Considering the T-cell dysfunction and disordered cytokine-network reported in AD, it was strongly suggested that MIF was a critical protein for immunoregulation in the pathophysiological mechanism of AD. In this context, MIF may become a useful laboratory parameter to comprehend the clinical course of the disease.

Macrophage migration inhibitory factor in the human ovary: presence in the follicular fluids and production by granulosa cells

Cytokines play an important role in ovarian function. We unexpectedly found high expression of macrophage migration inhibitory factor (MIF) mRNA in human ovarian tissues. Hence, we examined the presence of MIF in the follicular fluid because the follicular microenvironment is important for oocyte fecundity. The follicular fluids were collected from ovaries of patients undergoing in vitro fertilization and embryo transfer. A higher amount of MIF was identified in the follicular fluid, 80.3 +/- 4.6 ng/ml (mean +/- SE), in which the concentration was significantly decreased as the size of the follicles increased. To detect MIF mRNA expression in the granulosa cells, reverse transcription-polymerase chain reaction was carried out and this showed an amplified transcript specific for MIF. Furthermore, the presence of MIF protein in the granulosa cells was confirmed by Western blot analysis. These results suggest the possibility that MIF mediates various immunological events in the process of oocyte development.

Identification of macrophage migration inhibitory factor in human leukemia HL-60 cells and its induction by lipopolysaccharide

Cytokines play an important role in inflammation and immunity. In this study, we examined the expression and presence of human macrophage migration inhibitory factor (MIF) in human myelomonocytic leukemia cell line, HL-60 by reverse transcription-polymerase chain reaction (RT-PCR) and immunological methods (Western blot analysis and immunohistochemistry), respectively. The RT-PCR showed that MIF mRNA was constitutively expressed, and the expression was further induced by lipopolysaccharide (LPS) stimulation. The expression was upregulated by LPS at the range of 10 pg/ml to 10 ng/ml; however, it decreased at doses higher than 100 ng/ml. The expression reached the maximum 12 hr after the stimulation, but substantially decreased by 24 hr. Western blot analysis and immunohistochemistry using an anti-human MIF antibody revealed the presence of MIF protein in cytoplasm of the cells. The pathophysiological role of MIF in HL-60 cells has not been fully understood; however, the regulation of MIF mRNA expression by LPS suggests the possibility that the cytokine plays an important role in inflammatory events of leukemia.