Macrophage migration inhibitory factor: an emerging therapeutic target in rheumatoid arthritis

OxMIF: a druggable isoform of macrophage migration inhibitory factor in cancer and inflammatory diseases

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine with a pleiotropic spectrum of biological functions implicated in the pathogenesis of cancer and inflammatory diseases. MIF is constitutively present in several cell types and non-lymphoid tissues and is secreted after acute stress or inflammation. MIF triggers the release of proinflammatory cytokines, overrides the anti-inflammatory effects of glucocorticoids, and exerts chemokine function, resulting in increased migration and recruitment of leukocytes into inflamed tissue. Despite this, MIF is a challenging target for therapeutic intervention because of its ubiquitous nature and presence in the circulation and tissue of healthy individuals. Oxidized MIF (oxMIF) is an immunologically distinct disease-related structural isoform found in the plasma and tissues of patients with inflammatory diseases and in solid tumor tissues. MIF converts to oxMIF in an oxidizing, inflammatory environment. This review discusses the biology and activity of MIF and the potential for autoimmune disease and cancer modification by targeting oxMIF. Anti-oxMIF antibodies reduce cancer cell invasion/migration, angiogenesis, proinflammatory cytokine production, and ERK and AKT activation. Anti-oxMIF antibodies also elicit apoptosis and alter immune cell function and/or migration. When co-administered with a glucocorticoid, anti-oxMIF antibodies produced a synergistic response in inflammatory models. Anti-oxMIF antibodies therefore counterregulate biological activities attributed to MIF. oxMIF expression has been observed in inflammatory diseases (eg, sepsis, psoriasis, asthma, inflammatory bowel disease, and systemic lupus erythematosus) and oxMIF has been detected in ovarian, colorectal, lung, and pancreatic cancers. In contrast to MIF, oxMIF is specifically detected in plasma and/or tissues of diseased patients, but not in healthy individuals. Therefore, as a druggable isoform of MIF, oxMIF represents a potential new therapeutic target in inflammatory diseases and cancer. Fully human, monoclonal anti-oxMIF antibodies have been shown to selectively bind oxMIF in preclinical and phase I studies; however, additional clinical assessments are necessary to validate their use as either a monotherapy or in combination with standard-of-care regimens (ie, immunomodulatory agents/checkpoint inhibitors, anti-angiogenic drugs, chemotherapeutics, and glucocorticoids).

Macrophage Migration Inhibitory Factor (MIF) Expression Increases during Myocardial Infarction and Supports Pro-Inflammatory Signaling in Cardiac Fibroblasts

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine known to play a major role in inflammatory diseases such as myocardial infarction (MI), where its expression increases. Cardio-protective functions of MIF during ischemia have been reported. Recently, the structurally related MIF-2 was identified and similar effects are assumed. We wanted to further investigate the role of MIF and MIF-2 on inflammatory processes during MI. Therefore, we subjected mice to experimentally induced MI by coronary occlusion for one and five days. During the acute phase of MI, the gene expression of Mif was upregulated in the infarct zone, whereas Mif-2 was downregulated, suggesting a minor role of MIF-2. Simulating ischemic conditions or mechanical stress in vitro, we demonstrated that Mif expression was induced in resident cardiac cells. To investigate possible auto-/paracrine effects, cardiomyocytes and cardiac fibroblasts were individually treated with recombinant murine MIF, which in turn induced Mif expression and the expression of pro-inflammatory genes in cardiac fibroblasts. Cardiomyocytes did not respond to recombinant MIF with pro-inflammatory gene expression. While MIF stimulation alone did not change the expression of pro-fibrotic genes in cardiac fibroblasts, ischemia reduced their expression. Mimicking the increased MIF levels during MI, we exposed cardiac fibroblasts to simulated ischemia in the presence of MIF, which led to further reduced expression of pro-fibrotic genes. The presented data show that MIF was expressed by resident cardiac cells during MI. In vitro, Mif expression was induced by different external stimuli in cardiomyocytes and cardiac fibroblasts. Addition of recombinant MIF protein increased the expression of pro-inflammatory genes in cardiac fibroblasts including Mif expression itself. Thereby, cardiac fibroblasts may amplify Mif expression during ischemia promoting cardiomyocyte survival.

Association of CD14 and macrophage migration inhibitory factor gene polymorphisms with inflammatory microRNAs expression levels in ankylosing spondylitis and polyarthralgia

This study aimed to investigate the genetic basis of ankylosing spondylitis (AS) and polyarthralgia (PA) conditions among Indian subjects through genotyping two immune regulatory genes CD14 (-159C>T) and MIF (-173G>C) and find their association with the expression levels of three circulating inflammatory miRNAs. This investigation may provide early genetic cause of these two forms of arthritis and more optimal biological targets to predict early therapeutic outcomes. A total of 140 patients (AS: 70 and PA: 70) and 156 controls were recruited from Indian population. CD14 and MIF genotyping was performed using ARMS-PCR. Expression level of three inflammatory miRNAs (miRNA-146a, miRNA-155 and miRNA-181) was quantified using RT-qPCR. C/T genotype of CD14 gene was found to cause 2.06-fold risk of developing AS (CI 1.06-5.98, p = .04) as compared to others and G/C genotype in MIF also shown significant variation between AS and control subjects. In PA subjects, CD14 genotypes (C/T) was found to be associated with disease susceptibility and G/C genotype of MIF gene polymorphism showed 4.71-fold risk of developing PA (CI 2.58-8.62, p = .0001). The study also revealed significant upregulation of miRNA-155 expression in AS subjects (p = .0001) with more than 1.3-fold difference between AS and PA as compared to the control subjects. miRNA-155 had strong association with AS patients with CD14 genotypes (p < .05) than PA and control subjects. This study provides better understanding of the mechanisms and disease susceptibility for MIF and CD14 genetic variants and inflammatory miRNAs networks involved in AS and PA.

Characterization of a secreted macrophage migration inhibitory factor homologue of the parasitic nematode Haemonchus Contortus acting at the parasite-host cell interface

Modulation and suppression of the immune response of the host by nematode parasites have been reported extensively and the migration inhibitory factor (MIF) is identified as one of the major immunomodulator. In the present study, we cloned and produced recombinant MIF protein from the small ruminant’s nematode parasite Haemonchus contortus (rHCMIF-1), and investigated its immunomodulatory effects on goat monocyte. Enzymatic assays indicated that rHCMIF-1 possessed tautomerase activity. Immunohistochemical test demonstrated that the native HCMIF-1 protein was predominantly localized at the body surface and internal surface of the worm’s gut. We demonstrated that rHCMIF-1 could be distinguished by antisera from goats experimentally infected with H. contortus and could bind by goat monocytes. The immunomodulatory effects of HCMIF-1 on cytokine secretion, MHC molecule expression, NO production and phagocytosis were observed by co-incubation of rHCMIF-1 with goat monocytes. The results showed that the interaction of rHCMIF-1 decreased the production of TNF-α, IL-1β and IL-12p40, where as, it significantly increased the secretion of IL-10 and TGF β in goat monocytes. After rHCMIF-1 exposure, the expression of MHC-II on goat monocytes was inhibited. Moreover, rHCMIF-1 could down-regulate the LPS induced NO production of goat monocytes. Phagocytotic assay by FITC-dextran internalization showed that rHCMIF-1 could inhibit the phagocytosis of goat monocytes. Our findings provided potential targetas immunoregulator, and will be helpful to elucidate the molecular basis of host–parasite interactions and search for new potential protein as vaccine and drug target candidate.

Macrophage Migration Inhibitory Factor Limits Renal Inflammation and Fibrosis by Counteracting Tubular Cell Cycle Arrest

Renal fibrosis is a common underlying process of progressive kidney diseases. We investigated the role of macrophage migration inhibitory factor (MIF), a pleiotropic proinflammatory cytokine, in this process. In mice subjected to unilateral ureteral obstruction, genetic deletion or pharmacologic inhibition of MIF aggravated fibrosis and inflammation, whereas treatment with recombinant MIF was beneficial, even in established fibrosis. In two other models of progressive kidney disease, global Mif deletion or MIF inhibition also worsened fibrosis and inflammation and associated with worse kidney function. Renal MIF expression was reduced in tubular cells in fibrotic compared with healthy murine and human kidneys. Bone marrow chimeras showed that Mif expression in bone marrow-derived cells did not affect fibrosis and inflammation after UUO. However, Mif gene deletion restricted to renal tubular epithelial cells aggravated these effects. In LPS-stimulated tubular cell cultures, Mif deletion led to enhanced G2/M cell-cycle arrest and increased expression of the CDK inhibitor 1B (p27Kip1) and of proinflammatory and profibrotic mediators. Furthermore, MIF inhibition reduced tubular cell proliferation in vitro In all three in vivo models, global Mif deletion or MIF inhibition caused similar effects and attenuated the expression of cyclin B1 in tubular cells. Mif deletion also resulted in reduced tubular cell apoptosis after UUO. Recombinant MIF exerted opposing effects on tubular cells in vitro and in vivo Our data identify renal tubular MIF as an endogenous renoprotective factor in progressive kidney diseases, raising the possibility of pharmacologic intervention with MIF pathway agonists, which are in advanced preclinical development.

Reduced Osteoarthritis Severity in Aged Mice With Deletion of Macrophage Migration Inhibitory Factor

OBJECTIVE

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is elevated in the serum and synovial fluid of patients with osteoarthritis (OA). This study was undertaken to investigate the potential role of MIF in OA in human joint tissues and in vivo in mice with age-related and surgically induced OA.

METHODS

MIF in conditioned media from human chondrocytes and meniscal cells and from cartilage explants was measured by enzyme-linked immunosorbent assay. The severity of OA was analyzed histologically in male wild-type and MIF^-/- mice at 12 and 22 months of age and following destabilization of the medial meniscus (DMM) surgery in 12-week-old MIF^-/- mice as well as in wild-type mice treated with a neutralizing MIF antibody. Synovial hyperplasia was graded in S100A8-immunostained histologic sections. Bone morphometric parameters were measured by micro-computed tomography.

RESULTS

Human OA chondrocytes secreted 3-fold higher levels of MIF than normal chondrocytes, while normal and OA meniscal cells produced equivalent amounts. Compared to age- and strain-matched controls, the cartilage, bone, and synovium in older adult mice with MIF deletion were protected against changes of naturally occurring age-related OA. No protection against DMM-induced OA was seen in young adult MIF^-/- mice or in wild-type mice treated with anti-MIF. Increased bone density in 8-week-old mice with MIF deletion was not maintained at 12 months.

CONCLUSION

These results demonstrate a differential mechanism in the pathogenesis of naturally occurring age-related OA compared to injury-induced OA. The inhibition of MIF may represent a novel therapeutic target in the reduction of the severity of age-related OA.

MIF-2/D-DT enhances proximal tubular cell regeneration through SLPI- and ATF4-dependent mechanisms

Macrophage migration inhibitory factor (MIF) is a cytokine with pleiotropic actions that is produced by several organs and cell types. Depending on the target cell and the inflammatory context, MIF can engage its two component receptor complex CD74 and CD44 and the chemokine receptors CXCR2/4. MIF is constitutively expressed in renal proximal tubular cells, stored in intracellular preformed pools, and released at a low rate. Recently, a second MIF-like protein (i.e., MIF-2/D-DT) has been characterized in mammals. Our study was aimed at examining the role of MIF-2/D-DT, which mediates tissue protection in the heart, in tubular cell regeneration from ischemia-reperfusion injury. We found that Mif-/-, Mif-2-/-, and Cd74-/- mice had significantly worse tubular injury compared with wild-type (WT) control mice and that treatment with MIF-2/D-DT significantly improved recovery of injured epithelial cells. RNAseq analysis of kidney tissue from the ischemia-reperfusion injury model revealed that MIF-2/D-DT treatment stimulates secretory leukocyte proteinase inhibitor (SLPI) and cyclin D1 expression. MIF-2/D-DT additionally activates of eukaryotic initiation factor (eIF) 2α and activating transcription factor (ATF) 4, two transcription factors involved in the integrated stress response (ISR), which is a cellular stress response activated by hypoxia, nutrient deprivation, and oxygen radicals. MIF-2/D-DT also inhibited apoptosis and induced autophagy in hypoxia-treated mouse proximal tubular (MPT) cells. These results indicate that MIF-2/D-DT is an important factor in tubular cell regeneration and may be of therapeutic utility as a regenerative agent in the clinical setting of ischemic acute kidney injury.

Macrophage migration inhibitory factor promotes cardiac stem cell proliferation and endothelial differentiation through the activation of the PI3K/Akt/mTOR and AMPK pathways

Macrophage migration inhibitory factor (MIF) has pleiotropic immune functions in a number of inflammatory diseases. Recent evidence from expression and functional studies has indicated that MIF is involved in various aspects of cardiovascular disease. In this study, we aimed to determine whether MIF supports in vitro c-kit⁺CD45⁻ cardiac stem cell (CSC) survival, proliferation and differentiation into endothelial cells, as well as the possible mechanisms involved. We observed MIF receptor (CD74) expression in mouse CSCs (mCSCs) using PCR and immunofluorescence staining, and MIF secretion by mCSCs using PCR and ELISA in vitro. Increasing amounts of exogenous MIF did not affect CD74 expression, but promoted mCSC survival, proliferation and endothelial differentiation. By contrast, treatment with an MIF inhibitor (ISO-1) or siRNA targeting CD74 (CD74-siRNA) suppressed the biological changes induced by MIF in the mCSCs. Increasing amounts of MIF increased the phosphorylation of Akt and mammalian target of rapamycin (mTOR), which are known to support cell survival, proliferation and differentiation. These effects of MIF on the mCSCs were abolished by LY294002 [a phosphoinositide 3-kinase (PI3K) inhibitor] and MK-2206 (an Akt inhibitor). Moreover, adenosine monophosphate-activated protein kinase (AMPK) phosphorylation increased following treatment with MIF. The AMPK inhibitor, compound C, partly blocked the pro-proliferative effects of MIF on the mCSCs. In conclusion, our results suggest that MIF promotes mCSC survival, proliferation and endothelial differentiation through the activation of the PI3K/Akt/mTOR and AMPK signaling pathways. Thus, MIF may prove to be a potential therapeutic factor in the treatment of heart failure and myocardial infarction by activating CSCs.

Macrophage Migration Inhibitory Factor Mediates Proliferative GN via CD74

Pathologic proliferation of mesangial and parietal epithelial cells (PECs) is a hallmark of various glomerulonephritides. Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that mediates inflammation by engagement of a receptor complex involving the components CD74, CD44, CXCR2, and CXCR4. The proliferative effects of MIF may involve CD74 together with the coreceptor and PEC activation marker CD44. Herein, we analyzed the effects of local glomerular MIF/CD74/CD44 signaling in proliferative glomerulonephritides. MIF, CD74, and CD44 were upregulated in the glomeruli of patients and mice with proliferative glomerulonephritides. During disease, CD74 and CD44 were expressed de novo in PECs and colocalized in both PECs and mesangial cells. Stress stimuli induced MIF secretion from glomerular cells in vitro and in vivo, in particular from podocytes, and MIF stimulation induced proliferation of PECs and mesangial cells via CD74. In murine crescentic GN, Mif-deficient mice were almost completely protected from glomerular injury, the development of cellular crescents, and the activation and proliferation of PECs and mesangial cells, whereas wild-type mice were not. Bone marrow reconstitution studies showed that deficiency of both nonmyeloid and bone marrow-derived Mif reduced glomerular cell proliferation and injury. In contrast to wild-type mice, Cd74-deficient mice also were protected from glomerular injury and ensuing activation and proliferation of PECs and mesangial cells. Our data suggest a novel molecular mechanism and glomerular cell crosstalk by which local upregulation of MIF and its receptor complex CD74/CD44 mediate glomerular injury and pathologic proliferation in GN.

Self-rated health among pregnant women: associations with objective health indicators, psychological functioning, and serum inflammatory markers

BACKGROUND

Biobehavioral correlates of self-rated health in pregnancy are largely unknown.

PURPOSE

The goals of this study were to examine, in pregnant women, associations of self-rated health with (1) demographics, objective health status, health behaviors, and psychological factors, and (2) serum inflammatory markers.

METHODS

In the second trimester of pregnancy, 101 women provided a blood sample, completed measures of psychosocial stress, health status, and health behaviors, and received a comprehensive periodontal examination.

RESULTS

The following independently predicted poorer self-rated health: (1) greater psychological stress, (2) greater objective health diagnoses, (3) higher body mass index, and (4) past smoking (versus never smoking). Poorer self-rated health was associated with higher serum interleukin-1β (p = 0.02) and marginally higher macrophage migration inhibitory factor (p = 0.06). These relationships were not fully accounted for by behavioral/psychological factors.

CONCLUSIONS

This study provides novel data regarding factors influencing subjective ratings of health and the association of self-rated health with serum inflammatory markers in pregnant women.

Differential roles of cardiac and leukocyte derived macrophage migration inhibitory factor in inflammatory responses and cardiac remodelling post myocardial infarction

Myocardial infarction (MI) provokes regional inflammation which facilitates the healing, whereas excessive inflammation leads to adverse cardiac remodelling. Our aim was to determine the role of macrophage migration inhibitory factor (MIF) in inflammation and cardiac remodelling following MI. Wild type (WT) or global MIF deficient (MIFKO) mice were subjected to coronary artery occlusion. Compared to WT mice, MIFKO mice had a significantly lower incidence of post-MI cardiac rupture (27% vs. 53%) and amelioration of cardiac remodelling. These were associated with suppressed myocardial leukocyte infiltration, inflammatory mediators' expression, and reduced activity of MMP-2, MMP-9, p38 and JNK MAPK. Infarct myocardium-derived or exogenous MIF mediated macrophage chemotaxis in vitro that was suppressed by inhibition of p38 MAPK or NF-κB. To further dissect the role of MIF derived from different cellular sources in post-MI cardiac remodelling, we generated chimeric mice with MIF deficiency either in bone marrow derived-cells (WT(KO)) or in somatic-cells (KO(WT)). Compared to WT and KO(WT) mice, WT(KO) mice had reduced rupture risk and ameliorated cardiac remodelling, associated with attenuated regional leukocyte infiltration and expression of inflammatory mediators. In contrast, KO(WT) mice had delayed healing and enhanced expression of M1 macrophage markers, but diminished expression of M2 markers during the early healing phase. In conclusion, global MIF deletion protects the heart from post-infarct cardiac rupture and remodelling through suppression of leukocyte infiltration and inflammation. Leukocyte-derived MIF promotes inflammatory responses after MI, whereas cardiac-derived MIF affects early but not ultimate healing process.

Macrophage migration inhibitory factor polymorphism and the risk of ulcerative colitis and Crohn's disease in Asian and European populations: a meta-analysis

OBJECTIVE

To determine whether macrophage migration inhibitory factor (MIF) gene polymorphism is associated with the risk of inflammatory bowel disease (IBD).

DESIGN

System review and meta-analysis.

METHODS

MEDLINE, EMBASE, Web of Science databases, Cochrane Library and the Chinese Biomedical Literature database (CBM) were searched for the case-control trails for MIF and IBD. All the studies included in this manuscript met the inclusion and exclusion criteria. An OR analysis using a 95% CI was employed to assess the association of the MIF-173 G/C polymorphism with IBD susceptibility.

RESULTS

There was a significant association between the MIF-173 G/C gene polymorphism and IBD in the total population under the recessive model (CC vs GC+GG; OR=1.75, CI 1.04 to 2.95, p=0.04 for heterogeneity) and the codominant model (CC vs GG; OR=1.74, CI 1.02 to 2.97, p=0.04 for heterogeneity). In the stratified analysis by ethnicity, significantly increased risks were observed for Asians using the recessive (OR=1.75, CI 1.04 to 2.95, p=0.04 for heterogeneity) and codominant models (OR=1.74, CI 1.02 to 2.97, p=0.04 for heterogeneity). Within the subgroups of UC and CD, significant differences were observed regarding UC using the recessive (OR=1.60, CI 1.09 to 2.35, p=0.02 for heterogeneity) and codominant models (OR=1.64, CI 1.12 to 2.41, p=0.01 for heterogeneity). In the stratified analysis by ethnicity for UC, significant differences were observed regarding CC in Asians vs GC+GG (OR=1.73, CI 1.02 to 2.94, p=0.04 for heterogeneity).

CONCLUSIONS

The meta-analysis suggested that the MIF-173 G/C polymorphism contributed to the susceptibility of IBD. When considering the subgroups of ethnicity and UC and CD, the results suggested that the polymorphism is more significant for UC in Asians.

Identification and expression of macrophage migration inhibitory factor in Sarcoptes scabiei

Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine produced by many mammalian tissues including skin. It is also found in many invertebrate parasites of mammals including ticks and may function to aid the parasite to evade the innate and adaptive immune responses in the host. In this study, the cDNA for a MIF gene was sequenced from Sarcoptes scabiei, the scabies mite, using RT-PCR and RACE molecular techniques. The resulting nucleotide sequence had a length of 405 base pairs and the putative amino acid sequences for the mite and tick (Dermacentor variabilis) proteins were identical. The initial steps for the project resulted in the production of expressed scabies mite cDNAs. A real time (qPCR) assay was performed with MIF from scabies mites and various tick species. Results show that mRNA encoding MIF homologues was three times more abundant in the mite samples when compared to RNA prepared from D. variabilis salivary glands and 1.3 times more abundant when compared with RNA prepared from D. variabilis midgut.

MIF, CD74 and other partners in kidney disease: tales of a promiscuous couple

Macrophage migration inhibitory factor (MIF) is increased in kidney and urine during kidney disease. MIF binds to and activates CD74 and chemokine receptors CXCR2 and CXCR4. CD74 is a protein trafficking regulator and a cell membrane receptor for MIF, D-dopachrome tautomerase (D-DT/MIF-2) and bacterial proteins. MIF signaling through CD74 requires CD44. CD74, CD44 and CXCR4 are upregulated in renal cells in diseased kidneys and MIF activation of CD74 in kidney cells promotes an inflammatory response. MIF or CXCR2 targeting protects from experimental kidney injury, CD44 deficiency modulates kidney injury and CXCR4 activation promotes glomerular injury. However, the contribution of MIF or MIF-2 to these actions of MIF receptors has not been explored. The safety and efficacy of strategies targeting MIF, CD74, CD44 and CXCR4 are under study in humans.

Anti-inflammatory iridoids of botanical origin

Inflammation is a manifestation of a wide range of disorders which include; arthritis, atherosclerosis, Alzheimer's disease, inflammatory bowel syndrome, physical injury and infection amongst many others. Common treatment modalities are usually nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin, paracetamol, indomethacin and ibuprofen as well as corticosteroids such as prednisone. These however, may be associated with a host of side effects due to non-selectivity for cyclooxygenase (COX) enzymes involved in inflammation and those with selectivity may be highly priced. Thus, there is a continuing search for safe and effective antiinflammatory molecules from natural sources. Research has confirmed that iridoids exhibit promising anti-inflammatory activity which may be beneficial in the treatment of inflammation. Iridoids are secondary metabolites present in various plants, especially in species belonging to the Apocynaceae, Lamiaceae, Loganiaceae, Rubiaceae, Scrophulariaceae and Verbenaceae families. Many of these ethnobotanicals have an illustrious history of traditional use alluding to their use to treat inflammation. Although iridoids exhibit a wide range of pharmacological activities such as cardiovascular, hepatoprotection, hypoglycaemic, antimutagenic, antispasmodic, anti-tumour, antiviral, immunomodulation and purgative effects this review will acutely focus on their anti-inflammatory properties. The paper aims to present a summary for the most prominent iridoid-containing plants for which anti-inflammatory activity has been demonstrated in vitro and / or in vivo.

Macrophage migration inhibitory factor enhances osteoclastogenesis through upregulation of RANKL expression from fibroblast-like synoviocytes in patients with rheumatoid arthritis

INTRODUCTION

Macrophage migration inhibitory factor (MIF) is one of key regulators in acute and chronic immune-inflammatory conditions including rheumatoid arthritis (RA). We examined the effect of MIF on osteoclastogenesis, which is known to play a crucial role in bone destruction in RA.

METHODS

The concentration of MIF and receptor activator of nuclear factor-κB ligand (RANKL) in the synovial fluid was measured by ELISA. MIF-induced RANKL expression of RA synovial fibroblasts was determined by real-time PCR and western blot. Osteoclastogenesis was analyzed in culture of human peripheral blood mononuclear cells (PBMC) with MIF. Osteoclastogenesis was also determined after co-cultures of rhMIF-stimulated RA synovial fibroblasts with human PBMC.

RESULTS

Synovial fluid MIF concentration in RA patients was significantly higher than in osteoarthritis (OA) patients. The concentration of RANKL correlated with that of MIF in RA synovial fluids (r = 0.6, P < 0.001). MIF stimulated the expression of RANKL mRNA and protein in RA synovial fibroblasts, which was partially reduced by blocking of interleukin (IL)-1β. Osteoclasts were differentiated from PBMC cultures with MIF and M-CSF, even without RANKL. Osteoclastogenesis was increased after co-culture of MIF-stimulated RA synovial fibroblasts with PBMC and this effect was diminished by RANKL neutralization. Blocking of PI3 kinase, p38 MAP kinase, JAK-2, NF-κB, and AP-1 also led to a marked reduction in RANKL expression and osteoclastogenesis.

CONCLUSIONS

The interactions among MIF, synovial fibroblasts, osteoclasts, RANKL, and IL-1β have a close connection in osteoclastogenesis and they could be a potential gateway leading to new therapeutic approaches in treating bone destruction in RA.

Induction of macrophage migration inhibitory factor in ConA-stimulated rheumatoid arthritis synovial fibroblasts through the P38 map kinase-dependent signaling pathway

BACKGROUND/AIMS

This study was undertaken to identify the intracellular signaling pathway involved in induction of macrophage migration inhibitory factor (MIF) in human rheumatoid arthritis (RA) synovial fibroblasts.

METHODS

Human RA synovial fibroblasts were treated with concanavalin A (ConA), various cytokines, and inhibitors of signal transduction molecules. The production of MIF by synovial fibroblasts was measured in culture supernatants by ELISA. The expression of MIF mRNA was determined using reverse transcriptase polymerase chain reaction (RT-PCR) and real-time PCR. Phosphorylation of p38 mitogen-activated protein (MAP) kinase in synovial fibroblasts was confirmed using Western blotting. The expression of MIF and p38 MAP kinase in RA synovium was determined using dual immunohistochemistry.

RESULTS

The production of MIF by RA synovial fibroblasts increased in a dose-dependent manner after ConA stimulation. MIF was also induced by interferon-γ, CD40 ligand, interleukin-15, interleukin-1β, tumor necrosis factor-α, and transforming growth factor-β. The production of MIF by RA synovial fibroblasts was significantly reduced after inhibition of p38 MAP kinase. The expression of MIF and p38 MAP kinase was upregulated in the RA synovium compared with the osteoarthritis synovium.

CONCLUSIONS

These results suggest that MIF production was induced through a p38 MAP-kinase-dependent pathway in RA synovial fibroblasts.

Association of Macrophage Migration Inhibitory Factor Gene Promoter Polymorphisms with Multiple Sclerosis in Turkish Patients

Elevated levels of macrophage migration inhibitory factor (MIF) have been observed in the cerebrospinal fluid of patients with multiple sclerosis. This study was designed to determine if MIF gene polymorphisms are associated with multiple sclerosis and disease severity. In total, 120 relapsing-remitting patients with multiple sclerosis and 120 control subjects were enrolled in the study. There was a statistically significant increase in the MIF −173 CC genotype in patients with multiple sclerosis compared with the control subjects. The MIF −794 6/7 genotype had a significantly lower progression index compared with MIF −794 6/6. Patients with the MIF −173 CC genotype had a significantly lower age of disease onset compared with those with the MIF −173 CG and MIF −173 GG genotypes. Additionally, patients with the MIF −794 5/6 genotype had a significantly later age of disease onset. This study indicates that the MIF −173 CC genotype may cause susceptibility to multiple sclerosis in the white Turkish population and a younger age of disease onset is associated with this polymorphism.

Depressive symptoms predict exaggerated inflammatory responses to an in vivo immune challenge among pregnant women

OBJECTIVE

Stress and depressive symptoms predict exaggerated inflammatory responses to a biological challenge in nonpregnant humans and animals. The extent to which these findings generalize to pregnancy is unknown because the immune system exhibits substantial changes to support pregnancy. Notably, inflammatory responses to infectious agents play a causal role in the development of gestational hypertension as well as risk for preterm birth. Thus, depressive symptoms may increase susceptibility to these outcomes via sensitization of inflammatory processes. The current study was designed to test the hypothesis that depressive symptoms would predict an exaggerated proinflammatory response to an in vivo antigen challenge, influenza virus vaccination, among pregnant women.

METHOD

Twenty-two pregnant women completed two study visits: baseline and 1week after receiving influenza virus vaccination. Depressive symptoms were measured with the Center for Epidemiologic Studies Depression Scale (CES-D) at baseline. Serum levels of macrophage migration inhibitory factor (MIF) were determined using a high sensitivity immunoassay at both study visits.

OUTCOMES

Analyses demonstrated that, as compared to those in the lowest tertile of CES-D scores, those in the highest tertile exhibited significantly higher levels of MIF 1week after influenza virus vaccination (p=.035).

CONCLUSIONS

Depressive symptoms predicted exaggerated MIF production following influenza virus vaccination during pregnancy. These data support the hypothesis that depressive symptoms are associated with sensitization of the inflammatory response during pregnancy. Thus, women with greater depressive symptoms may be more vulnerable to negative sequelae of infectious illness during pregnancy.

High expression of macrophage migration inhibitory factor in the murine lacrimal gland

PURPOSE

To report the expression of macrophage migration inhibitory factor (MIF) in murine lacrimal glands.

METHODS

Six lacrimal glands from 3 female 8-week-old CBA/J mice were analyzed using a gene microarray method (Oligo GEArray mouse inflammatory cytokines and receptors, Catalog No. OMM-011, SuperArray Bioscience) and immunofluorescent staining for MIF. Nine lacrimal glands from 8-week-old CBA/J mice, 9 lacrimal glands from 8-week-old C57BL/6 mice, and 7 lacrimal glands from 8-week-old BALB/c mice were analyzed using real-time reverse transcription-polymerase chain reaction. Five spleens, 5 livers, and 5 serum samples from 5 female 8-week-old CBA/J mice were analyzed using enzyme-linked immunosorbent assay.

RESULTS

Microarray analysis revealed that MIF is highly expressed in the murine lacrimal gland. Lacrimal acinar cells stain strongly with anti-MIF antibodies. Real-time reverse transcription-polymerase chain reaction revealed that the MIF mRNA expression level is lower in lacrimal glands of CBA/J mice compared with C57BL/6 and BALB/c mice when normalized against the expression of beta-actin mRNA. Enzyme-linked immunosorbent assay revealed that MIF level was higher in lacrimal glands and spleens compared with livers and sera.

CONCLUSION

The murine lacrimal gland expresses high levels of macrophage MIF without any evidence of lacrimal gland inflammation.

G to C transition at position -173 of MIF gene of the recipient is associated with reduced relapse rates after allogeneic stem cell transplantation

Pro-inflammatory and dendritic cell-activating properties of macrophage migration inhibitory factor (MIF) suggest a potentially important role for MIF in alloantigen-specific immune responses after allogeneic stem cell transplantation (allo-SCT). We tested whether MIF -173 G/C gene polymorphism of donor or patient had impacts on the outcomes after allo-SCT. Four hundred and fifty-four donor-patient pairs were genotyped and mortality, relapse, and development of complications were analyzed. Patient but not donor MIF -173 *C allele was associated with improved overall survival (OS) (5 years: 60.8% versus 46.3%, p=0.042) and disease free survival (DFS) (5 years: 55.4% versus 39.5%; p=0.014) due to a reduction in relapse (day 2000: 22.8% versus 42.0% p=0.006) but not due to decreased transplantation-related mortality (TRM) (p=0.44). Multivariate analysis proved patient -173 *C allele as an independent factor for reducing relapse after allo-SCT (p=0.023). Subgroup analysis showed a clear MIF -173 *C allele-related reduction in relapse for those patients who did not receive T cell depleted (TCD) SCT (p=0.01) in contrast to patients receiving TCD SCT (p=0.20). In summary, patient MIF -173 *C allele may be linked to specific, yet unrevealed functions in tumor biology and graft versus leukemia and lymphoma effects and potentially presents a novel prognostic marker for patient-tailored counseling and therapy in allo-SCT.

Urine macrophage migration inhibitory factor (MIF) in children with urinary tract infection: a possible predictor of acute pyelonephritis

Macrophage migration inhibitory factor (MIF) is an important pro-inflammatory cytokine expressed at sites of inflammation. We have assessed this factor (MIF) in urinary tract infections with the aim of determining a non-invasive and sensitive method to differentiate upper and lower renal involvement. Thirty-three pediatric patients with urinary track infection (25 with acute pyelonephritis, eight with acute cystitis) and 40 healthy subjects were recruited for this prospective case-control study. Pyelonephritis was differentiated from cystitis by dimercaptosuccinic acid (DMSA) scan. Urinary MIF concentration was determined using an enzyme-linked immunosorbent assay method. The urine MIF/creatinine (Cr) ratio was significantly higher in pyelonephritis patients than in those with acute cystitis and the control group (P < 0.001). The optimal cut-point of 4.90 pg/micromol Cr for the urine MIF/Cr ratio has the potential to be a biomarker for distinguishing patients with acute pyelonephritis from those with acute cystitis. Determination of the urinary MIF was also useful in selecting the patients at risk of permanent renal damage. Of those patients with pyelonephritis, based on the DMSA scan at the time of infection, scarring on follow-up DMSA scan 9-12 months later occurred in patients with the highest urinary MIF/Cr ratios. We conclude that the urine MIF/Cr ratio is a sensitive test for differentiating acute pyelonephritis from acute cystitis and also for detecting children with acute pyelonephritis who are at a higher risk for permanent renal scars in the future.

Up-regulated macrophage migration inhibitory factor protects apoptosis of dermal fibroblasts in patients with systemic sclerosis

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that has been demonstrated to regulate the apoptosis of several cell types. Dysregulated apoptosis of fibroblasts has been implicated in a variety of fibrotic diseases, including systemic sclerosis (SSc). In this study, we investigated the role of MIF in the apoptosis of dermal fibroblasts. The concentrations of MIF were measured in sera and in culture supernatants of peripheral blood mononuclear cells (PBMCs) and dermal fibroblasts by enzyme-linked immunosorbent assay. The degree of apoptosis was determined by colorimetric assay, and signalling pathways were examined by Western blot. The results showed that serum levels of MIF were significantly higher in patients with SSc (n = 47) than in healthy controls (n = 56). Stimulation of PBMCs by anti-CD3 and anti-CD28 increased the production of MIF by fourfold over the constitutive levels. SSc dermal fibroblasts produced higher amounts of MIF than normal dermal fibroblasts. When treated with sodium nitroprusside (SNP), SSc dermal fibroblasts showed a lower degree of apoptosis compared with normal dermal fibroblasts. Exogenous MIF (1-100 ng/ml) inhibited SNP-induced apoptosis of dermal fibroblasts dose-dependently. Both extracellular regulated kinase (ERK) inhibitor (PD98059) and protein kinase B (Akt) inhibitor (LY294002) almost completely blocked the inhibitory effect of MIF on apoptosis. Furthermore, MIF increased the expression of Bcl-2, phospho-ERK and phospho-Akt activity in dermal fibroblasts. Taken together, our data suggest that MIF released by activated T cells and dermal fibroblasts decreases the apoptosis of dermal fibroblasts through activation of ERK, Akt and Bcl-2 signalling pathways, which might be associated with excessive fibrosis in SSc.

Differential and cell-type specific regulation of responses to Toll-like receptor agonists by ISO-1

Macrophage migration inhibitory factor (MIF) plays vital roles in the regulation of responses to stimuli acting via Toll-like receptor (TLR)-4. Recently, a specific small molecule inhibitor of MIF (ISO-1) has been described. We investigated the effects of ISO-1 on TLR responses in primary human monocytes and monocyte-derived macrophages (MDM). In monocytes, ISO-1 caused marked suppression of TLR4-induced proinflammatory cytokine production, and to a lesser extent suppression of TLR2-induced responses. The lipopolysaccharide (LPS)-induced activation of cocultures of monocytes and endothelial cells was strongly inhibited by ISO-1. Suppression of monocyte TLR4 signalling by ISO-1 was associated with alterations in extracellular signal-related kinase (ERK)-1/2 activation status. Previously, regulation of TLR4 signalling by MIF has been noted to be through control of TLR4 expression, but we observed that the actions of ISO-1 were mediated without changes in cell surface TLR4 levels. In contrast, ISO-1 pretreatment did not inhibit responses of MDM to LPS. ISO-1 is a promising parent molecule which inhibits TLR-induced ERK activation and inflammatory cytokine production in monocytes, whose role may be complicated by cell-type specificity.

Macrophage migration inhibitory factor gene: influence on rheumatoid arthritis susceptibility

The macrophage inhibitory factor (MIF) is a cytokine that has been implicated in several inflammatory and autoimmune diseases, including rheumatoid arthritis, systemic lupus, glomerulonephritis, and multiple sclerosis. In rheumatoid arthritis (RA), results ranging from lack of association of MIF polymorphisms with RA, to involvement in either severity or susceptibility to the disease have been reported in the past. We aimed at investigating the role of this gene in RA in the Spanish population. Two well-known MIF promoter polymorphisms were tested in 606 adult RA patients and 886 healthy controls: a single nucleotide polymorphism at -173G/C and a tetranucleotide repeat (CATT)(5-8) located at -794. We found a significant association of the allele -173C with RA (p = 0.01; odds ratio [OR] = 1.31; 95% confidence interval [CI] = 1.06-1.62). The -173C risk allele, previously reported to be transmitted in excess in patients with juvenile idiopathic arthritis, was significantly more frequent in early-onset adult RA patients than in healthy controls (p = 0.003; OR = 1.57; 95% CI = 1.14-2.15), whereas late-onset patients were not significantly different to controls (p = 0.6; OR = 1.09; 95% CI = 0.77-1.55). In conclusion, the -173C allele in the MIF promoter region is associated with increased RA predisposition, mainly in early-onset patients.

Macrophage migration inhibitory factor: gene polymorphisms and susceptibility to inflammatory diseases

The cytokine macrophage migration inhibitory factor (MIF) is a constitutive element of the host antimicrobial defenses and stress response that promotes proinflammatory function of the innate and acquired immune systems. MIF plays an important role in the pathogenesis of acute and chronic inflammatory or autoimmune disorders, such as sepsis, acute respiratory distress syndrome, asthma, rheumatoid arthritis, and inflammatory bowel diseases. Polymorphisms of the human MIF gene (that is, guanine-to-cytosine transition at position -173 or CATT-tetranucleotide repeat at position -794) have been associated with increased susceptibility to or severity of juvenile idiopathic and adult rheumatoid arthritis, ulcerative colitis, atopy, or sarcoidosis. Whether these MIF polymorphisms affect the susceptibility to and outcome of sepsis has not yet been examined. Analyses of MIF genotypes in patients with sepsis may help to classify patients into risk categories and to identify those patients who may benefit from anti-MIF therapeutic strategies.

Differential expression, function and response to inflammatory stimuli of 11beta-hydroxysteroid dehydrogenase type 1 in human fibroblasts: a mechanism for tissue-specific regulation of inflammation

Stromal cells such as fibroblasts play an important role in defining tissue-specific responses during the resolution of inflammation. We hypothesized that this involves tissue-specific regulation of glucocorticoids, mediated via differential regulation of the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). Expression, activity and function of 11β-HSD1 was assessed in matched fibroblasts derived from various tissues (synovium, bone marrow and skin) obtained from patients with rheumatoid arthritis or osteoarthritis. 11β-HSD1 was expressed in fibroblasts from all tissues but mRNA levels and enzyme activity were higher in synovial fibroblasts (2-fold and 13-fold higher mRNA levels in dermal and synovial fibroblasts, respectively, relative to bone marrow). Expression and activity of the enzyme increased in all fibroblasts following treatment with tumour necrosis factor-α or IL-1β (bone marrow: 8-fold and 37-fold, respectively, compared to vehicle; dermal fibroblasts: 4-fold and 14-fold; synovial fibroblasts: 7-fold and 31-fold; all P < 0.01 compared with vehicle). Treatment with IL-4 or interferon-γ was without effect, and there was no difference in 11β-HSD1 expression between fibroblasts (from any site) obtained from patients with rheumatoid arthritis or osteoarthritis. In the presence of 100 nmol/l cortisone, IL-6 production – a characteristic feature of synovial derived fibroblasts – was significantly reduced in synovial but not dermal or bone marrow fibroblasts. This was prevented by co-treatment with an 11β-HSD inhibitor, emphasizing the potential for autocrine activation of glucocorticoids in synovial fibroblasts. These data indicate that differences in fibroblast-derived glucocorticoid production (via the enzyme 11β-HSD1) between cells from distinct anatomical locations may play a key role in the predeliction of certain tissues to develop persistent inflammation.

A dynamic model of gene expression in monocytes reveals differences in immediate/early response genes between adult and neonatal cells

Neonatal monocytes display immaturity of numerous functions compared with adult cells. Gene expression arrays provide a promising tool for elucidating mechanisms underlying neonatal immune function. We used a well-established microarray to analyze differences between LPS-stimulated human cord blood and adult monocytes to create dynamic models for interactions to elucidate observed deficiencies in neonatal immune responses.

We identified 168 genes that were differentially expressed between adult and cord monocytes after 45 min incubation with LPS. Of these genes, 95% (159 of 167) were over-expressed in adult relative to cord monocytes. Differentially expressed genes could be sorted into nine groups according to their kinetics of activation. Functional modelling suggested differences between adult and cord blood in the regulation of apoptosis, a finding confirmed using annexin binding assays. We conclude that kinetic studies of gene expression reveal potentially important differences in gene expression dynamics that may provide insight into neonatal innate immunity.

MIF production by dendritic cells is differentially regulated by Toll-like receptors and increased during rheumatoid arthritis

Macrophage migration inhibitory factor (MIF) is clearly associated with rheumatoid arthritis (RA) disease severity. However, the regulation of MIF during the course of RA has not been subjected to similar scientific scrutiny. The aim of our study was to investigate the role of various Toll-like receptors (TLRs) and inflammatory mediators on MIF production by dendritic cells (DCs) in healthy controls and RA patients. DCs were cultured from 12 healthy donors and 12 RA patients. Triggering via TLR mediated pathways was achieved using various TLR specific ligands alone or in combination: Pam3Cys for TLR2, LPS and recombinant extra domain A containing fibronectin for TLR4 and Poly(I:C) and R848 for TLR3 and TLR7, respectively. In addition, iDCs from healthy controls were incubated with various cytokines, RANKL and CD40L for 48 h. MIF levels were measured using an ELISA assay. Stimulation of DCs by TLR4 ligands resulted in higher MIF production compared to immature DCs from healthy controls (p<0.002) and RA patients (p<0.002). DCs from RA patients produced higher MIF levels than healthy controls both at the immature stage (p<0.04) as well after full maturation via TLR2 (p<0.04) and TLR4 (p<0.001) triggering. Incubation with TLR3 and TLR7 ligands resulted in a significantly decreased secretion of MIF in RA patients and controls. Simultaneous incubation of TLR4 with either TLR3 or TLR7 ligands resulted in a decrease of MIF secretion when compared to TLR4 stimulation alone. The secretion of MIF increased when DCs were stimulated with TNF-alpha, RANKL and CD40L. The secretion of MIF by dendritic cells is differentially regulated by TLRs. In addition, TNF-alpha, RANKL, and CD40L augment MIF production by DCs and thus play a potential role in the amplification of the inflammatory loop in RA.

Rheumatoid arthritis: a review of the cutaneous manifestations

Rheumatoid arthritis is a chronic inflammatory arthritis with significant extra-articular manifestations. Of note are unique cutaneous manifestations that the dermatologist may encounter. This article will make the dermatologist more cognizant of these skin findings in patients with this systemic inflammatory disorder. It examines rheumatoid arthritis, focusing on the general nonspecific and disease-specific rheumatoid arthritic skin changes. Classic rheumatoid nodules, accelerated rheumatoid nodulosis, rheumatoid nodulosis, rheumatoid vasculitis, Felty syndrome, pyoderma gangrenosum, interstitial granulomatosus dermatitis with arthritis, palisaded neutrophilic and granulomatosis dermatitis, rheumatoid neutrophilic dermatitis, juvenile rheumatoid arthritis, and adult-onset Still disease are reviewed. Understanding the cutaneous expressions of rheumatoid arthritis may lead to early diagnosis, prompt treatment, and lower morbidity and mortality for the affected persons. Learning objective At the completion of this learning activity, participants should be able to describe rheumatoid arthritis in terms of its epidemiology, etiology, pathogenesis, and general and specific cutaneous manifestations.

Macrophage migration inhibitory factor-deficient mice are resistant to ovariectomy-induced bone loss

A link between macrophage migration inhibitory factor (MIF) and estrogen has recently emerged. We examined the involvement of MIF in osteoporotic changes in bone after ovariectomy (OVX), and revealed that MIF-deficient mice (MIF-KO) were completely protected from this phenomenon. The increase in osteoclast number per bone surface and serum IL-1beta levels, which were observed in wild-type mice after OVX, did not occur in MIF KO. Our data suggest that MIF plays an important role in the pathogenesis of postmenopausal osteoporosis, and could be a novel target for the treatment of this disease.

Cytokines and Escherichia coli Sepsis

This review reviews the critical role played by cytokines in the pathogenesis of Escherichia coli sepsis. It focuses on prototypic pro-inflammatory and anti-inflammatory cytokines and their influence on mortality in experimental animal models of E. coli endotoxemia and of live E. coli sepsis. The review reviews the results of clinical trials on anticytokine therapy in patients with severe sepsis or septic shock. The recognition of the critical role played by tumor necrosis factor (TNF), a secreted 17kDa cytokine, in endotoxic and gram-negative shock has been a major step forward in our understanding of the pathogenesis of sepsis. The review describes the role of TNF, IL1, and IL6 in animal models of E. coli endotoxemia and sepsis. Given the pivotal role played by TNF in experimental sepsis and the fact that elevated concentrations of TNF were detected in the circulation of patients with sepsis, anti-TNF treatment strategies were investigated as adjunctive therapy for severe sepsis and septic shock. Several studies demonstrated that high levels of interleukin-6 (IL-6) are associated with an increased risk for fatal outcome. Gamma interferon (IFN-γ), IL-12, and IL-18 are functionally related cytokines. A recent study has indicated that transgenic mice overexpressing IL-15 are resistant to an otherwise lethal intraperitoneal E. coli challenge. IL4, IL10, and IL13are prototypic anti-inflammatory cytokines. Their classification as anti-inflammatory cytokines is based on the observation that these molecules inhibit the production of proinflammatory cytokines (primarily TNF and IL1) and toxic oxygen and reactive nitrogen species by myeloid cells.

Increase in macrophage migration inhibitory factor levels in lacrimal fluid of patients with severe atopic dermatitis

BACKGROUND AND AIMS OF THE STUDY

Atopic dermatitis is a chronic inflammatory skin disorder that often involves some ophthalmic features. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine that is associated with the generation of cell-mediated immune responses. Although serum MIF levels may be elevated in severe atopic dermatitis, the quantity of MIF in regional ocular fluid remains unknown. We measured MIF levels in tears (lacrimal fluid) of patients with atopic dermatitis.

PATIENTS AND METHODS

Tear samples were collected from 16 patients with atopic dermatitis, 10 patients with allergic conjunctivitis, and 15 healthy control subjects. The clinical severity of atopic dermatitis was evaluated according to the Scoring Atopic Dermatitis (SCORAD) index. The index was calculated by summing the following scores: extent criteria, intensity criteria, and subjective symptoms. Macrophage migration inhibitory factor levels were determined by a human MIF enzyme-linked immunosorbent assay. All comparisons were two-tailed, and P values <0.01 were considered as statistically significant.

RESULTS

The mean MIF concentration in lacrimal fluid collected from healthy control subjects was 0.69+/-0.2 ng/ml. The mean tear MIF levels were 17.87+/-6.3 ng/ml in moderate-to-severe atopic dermatitis (SCORAD> or =15, P=0.002), 0.93+/-0.08 ng/ml in mild atopic dermatitis (SCORAD<15), and 2.76+/-0.86 ng/ml in allergic conjunctivitis (P=0.008).

CONCLUSIONS

A proinflammatory cytokine MIF level was elevated in tears as well as serum in cases of severe atopic dermatitis. These results suggest that MIF may play an important role in the induction or enhancement of ophthalmic features related to severe atopic dermatitis.

Use of the plasma stromelysin (matrix metalloproteinase 3) concentration to predict joint space narrowing in knee osteoarthritis

OBJECTIVE

To determine whether baseline or serial plasma concentrations of stromelysin (matrix metalloproteinase 3 [MMP-3]) protein might distinguish subjects with progressive radiographic knee osteoarthritis (OA) from those with stable disease.

METHODS

Subjects were 120 women with unilateral knee OA who participated in a 30-month randomized, placebo-controlled trial of structure modification with doxycycline. Anteroposterior views of both knees in a semiflexed position were obtained at baseline, 16 months, and 30 months. Subjects were selected to obtain comparisons of plasma MMP-3 levels between 60 progressors (21 taking doxycycline, 39 taking placebo) and 60 nonprogressors (30 taking doxycycline, 30 taking placebo) with respect to medial joint space narrowing (JSN) in the index knee. Each group consisted of 30 subjects who exhibited significant increases in knee pain. Blood samples were obtained semiannually for MMP-3 assay.

RESULTS

Subjects in the placebo group whose MMP-3 concentration was in the upper tertile of the baseline distribution showed a 4-fold increase in the odds of progression of JSN as compared with the lower tertile (odds ratio 4.12, P = 0.037). Baseline MMP-3 levels were unrelated to knee pain. The within-subject mean of serial MMP-3 concentrations was associated with concurrent JSN in the placebo group over the 0-16-month interval (b = 0.18 mm/SD increase in the mean MMP-3, P < 0.01) and over the 16-30-month interval (b = 0.15, P < 0.05). Similar evidence of concurrent validity was found in the placebo group for the maximum of intercurrent MMP-3 values.

CONCLUSION

The baseline MMP-3 level was a significant predictor of JSN in this pilot study. Moreover, serial plasma MMP-3 levels reflected concurrent JSN in the placebo group over the 30-month period of observation.

Correlation of rheumatoid arthritis severity with the genetic functional variants and circulating levels of macrophage migration inhibitory factor

OBJECTIVE

To study whether genetic variants of macrophage migration inhibitory factor (MIF), the MIF -173G>C and CATT(5-8) alleles, are associated with disease severity and levels of circulating MIF in patients with rheumatoid arthritis (RA).

METHODS

Genotyping was performed in patients with early RA and in healthy controls. Demographic data, disease activity, and outcome measurements were compared between patients with and without the MIF variants. MIF -173G>C and CATT(5-8) polymorphisms were genotyped, and a newly developed enzyme-linked immunosorbent assay for human MIF was used. Allele and genotype distributions of the MIF -173G>C and CATT(5-8) polymorphisms were compared between patients and controls by chi-square test. Multiple regression analysis was performed to assess the independence of the MIF functional genetic variants as risk factors for radiologic joint damage.

RESULTS

Genotyping of the -173G>C and CATT(5-8) polymorphisms of MIF in RA patients and healthy individuals (n = 277 each) revealed similar frequencies of genotypes and haplotypes in both groups. No significant differences in demographic or clinical features were observed between RA patients carrying the MIF -173C allele or the MIF CATT7 allele or both and non-carrier RA patients. Radiologic joint damage was significantly higher in patients carrying risk alleles of the MIF -173G>C or the MIF CATT(5-8) functional variants. No synergistic effects between both genetic variants were observed. Multivariate regression analysis revealed that presence of the MIF -173C/C and MIF CATT(7/7) genotypes and having 1 MIF -173C allele were independent prognostic variables. Carriership of the MIF -173C allele (P = 0.002) or MIF CATT7 allele (P = 0.004) was associated with significantly higher circulating MIF levels compared with those in subjects having none of the risk-conferring alleles, and greater circulating MIF levels correlated with more severe radiologic joint damage (r = 0.64, P = 0.001).

CONCLUSION

The MIF polymorphisms are not associated with RA susceptibility but are associated with high levels of radiologic joint damage. High circulating MIF levels were shown to correlate strongly with radiologic joint damage, suggesting that MIF expression is genetically determined and can be used as a novel prognostic tool in RA.

Elevated macrophage migration inhibitory factor (MIF) levels in the urine of patients with focal glomerular sclerosis

The pathogenesis of focal glomerular sclerosis (FGS) is poorly understood. Macrophage migration inhibitory factor (MIF) is a potent pro-inflammatory cytokine released from T cells and macrophages, and is a key molecule in inflammation. To examine further the possible role of MIF in FGS, we measured MIF levels in the urine. The purpose of the present study was to evaluate the involvement of MIF in FGS. Urine samples were obtained from 20 FGS patients. The disease controls included 40 patients with minimal-change nephrotic syndrome (MCNS) and membranous nephropathy (MN). A group of healthy subjects also served as controls. Biopsies were performed in all patients prior to entry to the study. The samples were assayed for MIF protein by a sandwich enzyme-linked immunosorbent assay (ELISA). The levels of MIF in the urine of FGS patients were significantly higher than those of the normal controls and patients with MCNS and MN. In contrast, the levels of urinary MIF (uMIF) in patients with MCNS and MN did not differ significantly from normal values. In the present study, attention also focused on the relationship between uMIF levels and pathological features. Among the patients with FGS, uMIF levels were significantly correlated with the grade of mesangial matrix increase and that of interstitial fibrosis. There was also a significant correlation between uMIF levels and the number of both intraglomerular and interstitial macrophages. Although the underlying mechanisms remain to be determined, our study presents evidence that urinary excretion of MIF is increased in FGS patients with active renal lesions.

Binding of JAB1/CSN5 to MIF is mediated by the MPN domain but is independent of the JAMM motif

Macrophage migration inhibitory factor (MIF) binds to c-Jun activation domain binding protein-1 (JAB1)/subunit 5 of COP9 signalosome (CSN5) and modulates cell signaling and the cell cycle through JAB1. The binding domain of JAB1 responsible for binding to MIF is unknown. We hypothesized that the conserved Mpr1p Pad1p N-terminal (MPN) domain of JAB1 may mediate binding to MIF. In fact, yeast two hybrid (YTH) and in vitro translation/coimmunoprecipitation (CoIP) analysis showed that a core MPN domain, which did not cover the functional JAB1/MPN/Mov34 metalloenzyme (JAMM) deneddylase sequence, binds to MIF comparable to full-length JAB1. YTH and pull-down analysis in conjunction with nanobead affinity matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry demonstrated that MIF(50-65) and MPN are sufficient to mediate MIF-JAB1 interaction, respectively. Finally, endogenous CoIP of MIF-CSN6 complexes from mammalian cells demonstrated that MPN is responsible for MIF-JAB1 binding in vivo, and, as CSN6 does not contain a functional JAMM motif, confirmed that the interaction does not require JAMM.

Association of higher levels of serum cartilage oligomeric matrix protein and N-telopeptide crosslinks with the development of radiographic hip osteoarthritis in elderly women

OBJECTIVE

To examine the association of baseline concentrations of serum cartilage oligomeric matrix protein (COMP) and serum N-telopeptide crosslinks (NTX) with the development and progression of radiographic hip osteoarthritis (RHOA) in elderly women.

METHODS

Pelvic radiographs were obtained a mean of 8.3 years apart from white women > or =65 years of age enrolled in the Study of Osteoporotic Fractures. Random sampling from a cohort of 5,928 subjects was performed, with subjects ( approximately 200 per group) assigned to nested case-control studies, one focusing on RHOA incidence and the other on RHOA progression. Baseline serum levels of COMP and NTX were measured by enzyme-linked immunosorbent assay in duplicate. Odds ratios (ORs) and 95% confidence intervals (95% CIs), indicating the likelihood of baseline serum COMP and NTX levels to be predictive of the development or progression of RHOA, were calculated using logistic regression analysis, with adjustment for potential covariates.

RESULTS

At baseline, incident cases of RHOA were associated with higher serum levels of COMP and NTX (P < 0.05 for each) compared with the no RHOA control group. Higher baseline serum COMP and NTX levels were associated with an increased risk of incident RHOA compared with the no RHOA group, with an adjusted OR of 1.31 per SD increase in COMP (95% CI 1.02-1.68) and adjusted OR of 1.38 per SD increase in NTX (95% CI 1.07-1.79). In this community-based cohort, progression of RHOA was modest. However, there was a trend toward increased risk of RHOA progression with higher baseline COMP and NTX levels.

CONCLUSION

These data suggest that serum levels of COMP and NTX are modest risk markers for the development of RHOA in a community-based cohort of elderly white women.

Combination anti-inflammatory therapy: synergism in rats of NSAIDs/corticosteroids with some herbal/animal products

A useful function of any complementary medicine is to supplement some of the benefits from other treatment modalities. In rats, extracts from Indian celery seed and the NZ green-lipped mussel are powerful nutraceuticals that (i) amplify the potency of salicylates and prednisone for treating pre-established chronic inflammation (arthritis, fibrosis) and (ii) reduce the steroid's gastrotoxic and lymphopenic side effects. Such combinations might also be useful for treating inflammatory components of (a) osteoarthritis caused by microcrystalline hydroxyapatite (BCP) and (b) pseudo-gout, associated with calcium pyrophosphate crystals; that are usually refractory to monotherapy.

Macrophage Migration Inhibitory Factor Gene Polymorphism is Associated with Psoriasis

Macrophage migration inhibitory factor (MIF), an important pro-inflammatory cytokine, is over-expressed in plaques of psoriasis and increased levels are found in the sera of patients with psoriasis. Promoter polymorphisms of the MIF gene are associated with increased production of MIF and have been found to confer increased risk of susceptibility to chronic inflammatory diseases. We investigated whether there is an association between promoter polymorphisms of the MIF gene and chronic plaque psoriasis. Two hundred and twenty-eight UK caucasian patients with chronic plaque psoriasis, and a control panel of 401 UK caucasian normal volunteers were studied. MIF promoter polymorphisms were genotyped by allelic discrimination, or by a fluorescently labeled primer method, and capillary gel electrophoresis. Carriage of either the MIF-173*C polymorphism or the MIF CATT(7) polymorphism was positively correlated with psoriasis (odds ratios (OR) 1.52 95% confidence intervals (CI) 1.05-2.19 (p=0.024) and OR 1.67 95% CI 1.1-2.5 (p=0.013), respectively. The OR for presence of the CATT(7)-MIF-173(*)C haplotype versus all other haplotypes combined was 1.69 95% CI 1.2-2.5 (p=0.008). The results provide evidence for polymorphisms in the MIF gene, and in particular the CATT(7)-MIF-173(*)C haplotype, being of importance in susceptibility to psoriasis.