Showing papers by "Richard Bucala published in 2011"

Fibrocytes: emerging effector cells in chronic inflammation

Abstract: Fibrocytes are mesenchymal cells that arise from monocyte precursors. They are present in injured organs and have both the inflammatory features of macrophages and the tissue remodelling properties of fibroblasts. Chronic inflammatory stimuli mediate the differentiation, trafficking and accumulation of these cells in fibrosing conditions associated with autoimmunity, cardiovascular disease and asthma. This Opinion article discusses the immunological mediators controlling fibrocyte differentiation and recruitment, describes the association of fibrocytes with chronic inflammatory diseases and compares the potential roles of fibrocytes in these disorders with those of macrophages and fibroblasts. It is hoped that this information prompts new opportunities for the study of these unique cells.

The D-dopachrome tautomerase (DDT) gene product is a cytokine and functional homolog of macrophage migration inhibitory factor (MIF)

Abstract: Macrophage migration inhibitory factor (MIF) is a pivotal regulator of the immune response. Neutralization or genetic deletion of MIF does not completely abrogate activation responses, however, and deletion of the MIF receptor, CD74, produces a more pronounced phenotype than MIF deficiency. We hypothesized that these observations may be explained by a second MIF-like ligand, and we considered a probable candidate to be the protein encoded by the homologous, D-dopachrome tautomerase (D-DT) gene. We show that recombinant D-DT protein binds CD74 with high affinity, leading to activation of ERK1/2 MAP kinase and downstream proinflammatory pathways. Circulating D-DT levels correlate with disease severity in sepsis or malignancy, and the specific immunoneutralization of D-DT protects mice from lethal endotoxemia by reducing the expression of downstream effector cytokines. These data indicate that D-DT is a MIF-like cytokine with an overlapping spectrum of activities that are important for our understanding of MIF-dependent physiology and pathology.

Macrophage migration inhibitory factor (MIF) exerts antifibrotic effects in experimental liver fibrosis via CD74

Abstract: Macrophage migration inhibitory factor (MIF) is a pleiotropic inflammatory cytokine that has been implicated in various inflammatory diseases. Chronic inflammation is a mainstay of liver fibrosis, a leading cause of morbidity worldwide, but the role of MIF in liver scarring has not yet been elucidated. Here we have uncovered an unexpected antifibrotic role for MIF. Mice genetically deleted in Mif (Mif−/−) showed strongly increased fibrosis in two models of chronic liver injury. Pronounced liver fibrosis in Mif−/− mice was associated with alterations in fibrosis-relevant genes, but not by a changed intrahepatic immune cell infiltration. Next, a direct impact of MIF on hepatic stellate cells (HSC) was assessed in vitro. Although MIF alone had only marginal effects on HSCs, it markedly inhibited PDGF-induced migration and proliferation of these cells. The inhibitory effects of MIF were mediated by CD74, which we detected as the most abundant known MIF receptor on HSCs. MIF promoted the phosphorylation of AMP-activated protein kinase (AMPK) in a CD74-dependent manner and, in turn, inhibition of AMPK reversed the inhibition of PDGF-induced HSC activation by MIF. The pivotal role of CD74 in MIF-mediated antifibrotic properties was further supported by augmented liver scarring of Cd74−/− mice. Moreover, mice treated with recombinant MIF displayed a reduced fibrogenic response in vivo. In conclusion, we describe a previously unexplored antifibrotic function of MIF that is mediated by the CD74/AMPK signaling pathway in HSCs. The results imply MIF and CD74 as targets for treatment of liver diseases.

A small-molecule macrophage migration inhibitory factor antagonist protects against glomerulonephritis in lupus-prone NZB/NZW F1 and MRL/lpr mice.

Abstract: Autoimmunity leads to the activation of innate effector pathways, proinflammatory cytokine production, and end-organ injury. Macrophage migration inhibitory factor (MIF) is an upstream activator of the innate response that mediates the recruitment and retention of monocytes via CD74 and associated chemokine receptors, and it has a role in the maintenance of B lymphocytes. High-expression MIF alleles also are associated with end-organ damage in different autoimmune diseases. We assessed the therapeutic efficacy of (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1), an orally bioavailable MIF antagonist, in two distinct models of systemic lupus erythematosus: the NZB/NZW F1 and the MRL/lpr mouse strains. ISO-1, like anti-MIF, inhibited the interaction between MIF and its receptor, CD74, and in each model of disease, it reduced functional and histological indices of glomerulonephritis, CD74(+) and CXCR4(+) leukocyte recruitment, and proinflammatory cytokine and chemokine expression. Neither autoantibody production nor T and B cell activation were significantly affected, pointing to the specificity of MIF antagonism in reducing excessive proinflammatory responses. These data highlight the feasibility of targeting the MIF-MIF receptor interaction by small-molecule antagonism and support the therapeutic value of downregulating MIF-dependent pathways of tissue damage in systemic lupus erythematosus.

Macrophage migration inhibitory factor and CD74 regulate macrophage chemotactic responses via MAPK and Rho GTPase.

Abstract: Macrophage migration inhibitory factor (MIF) promotes leukocyte recruitment to sites of inflammation. However, whether this stems from a direct effect on leukocyte migration is unknown. Furthermore, the role of the MIF-binding protein CD74 in this response has not been investigated. Therefore, the aim of this study was to examine the contributions of MIF and CD74 to chemokine-induced macrophage recruitment. Intravital microscopy studies demonstrated that CCL2-induced leukocyte adhesion and transmigration were reduced in MIF(-/-) and CD74(-/-) mice. MIF(-/-) and CD74(-/-) macrophages also exhibited reduced chemotaxis in vitro, although CD74(-/-) macrophages showed increased chemokinesis. Reduced CCL2-induced migration was associated with attenuated MAPK phosphorylation, RhoA GTPase activity, and actin polymerization in MIF(-/-) and CD74(-/-) macrophages. Furthermore, in MIF(-/-) macrophages, MAPK phosphatase-1 was expressed at elevated levels, providing a potential mechanism for the reduction in MAPK phosphorylation in MIF-deficient cells. No increase in MAPK phosphatase-1 expression was observed in CD74(-/-) macrophages. In in vivo experiments assessing the link between MIF and CD74, combined administration of MIF and CCL2 increased leukocyte adhesion in both MIF(-/-) and CD74(-/-) mice, showing that CD74 was not required for this MIF-induced response. Additionally, although leukocyte recruitment induced by administration of MIF alone was reduced in CD74(-/-) mice, consistent with a role for CD74 in leukocyte recruitment induced by MIF, MIF-treated CD74(-/-) mice displayed residual leukocyte recruitment. These data demonstrate that MIF and CD74 play previously unappreciated roles in CCL2-induced macrophage adhesion and migration, and they indicate that MIF and CD74 mediate this effect via both common and independent mechanisms.

Dual effect of the macrophage migration inhibitory factor gene on the development and severity of human systemic lupus erythematosus.

Abstract: Objective To study the effect of the innate cytokine macrophage migration inhibitory factor (MIF) on the susceptibility and severity of systemic lupus erythematosus (SLE) in a multinational population of 1,369 Caucasian and African American patients. Methods. Two functional polymorphisms in the MIF gene, a -794 CATT5-8 microsatellite repeat (rs5844572) and a -173 G/C single-nucleotide polymorphism (rs755622), were assessed for association with SLE in 3,195 patients and healthy controls. We also measured MIF plasma levels in relation to genotypes and clinical phenotypes, and assessed Toll-like receptor 7 (TLR-7)-stimulated MIF production in vitro. Results. Both Caucasians and African Americans with the high-expression MIF haplotype -794 CATT(7)/ -173* C had a lower incidence of SLE (in Caucasians, odds ratio [OR] 0.63, 95% confidence interval [95% CI] 0.53-0.89, P = 0.001; in African Americans, OR 0.46, 95% CI 0.23-0.95, P = 0.012). In contrast, among patients with established SLE, reduced frequencies of low-expression MIF genotypes (-794 CATT(5)) were observed in those with nephritis, those with serositis, and those with central nervous system (CNS) involvement when compared to patients without end-organ involvement (P = 0.023, P = 0.005, and P = 0.04, respectively). Plasma MIF levels and TLR-7-stimulated MIF production in vitro reflected the underlying MIF genotype of the studied groups. Conclusion. These findings suggest that MIF, which has both proinflammatory properties and macrophage and B cell survival functions, exerts a dual influence on the immunopathogenesis of SLE. Highexpression MIF genotypes are associated with a reduced susceptibility to SLE and may contribute to an enhanced clearance of infectious pathogens. Once SLE develops, however, low-expression MIF genotypes may protect from ensuing inflammatory end-organ damage.

Macrophage migration inhibitory factor promotes cell death and aggravates neurologic deficits after experimental stroke.

Abstract: Multiple mechanisms contribute to tissue demise and functional recovery after stroke. We studied the involvement of macrophage migration inhibitory factor (MIF) in cell death and development of neurologic deficits after experimental stroke. Macrophage migration inhibitory factor is upregulated in the brain after cerebral ischemia, and disruption of the Mif gene in mice leads to a smaller infarct volume and better sensory-motor function after transient middle cerebral artery occlusion (tMCAo). In mice subjected to tMCAo, we found that MIF accumulates in neurons of the peri-infarct region, particularly in cortical parvalbumin-positive interneurons. Likewise, in cultured cortical neurons exposed to oxygen and glucose deprivation, MIF levels increase, and inhibition of MIF by (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) protects against cell death. Deletion of MIF in Mif−/− mice does not affect interleukin-1β protein levels in the brain and serum after tMCAo. Furthermore, disruption of the Mif gene in mice does not affect CD68, but it is associated with higher galectin-3 immunoreactivity in the brain after tMCAo, suggesting that MIF affects the molecular/cellular composition of the macrophages/microglia response after experimental stroke. We conclude that MIF promotes neuronal death and aggravates neurologic deficits after experimental stroke, which implicates MIF in the pathogenesis of neuronal injury after stroke.

Circulating fibrocytes--biology and mechanisms in wound healing and scar formation.

Abstract: Fibrocytes were first described in 1994 as fibroblast-like, peripheral blood cells. These bone marrow-derived mesenchymal progenitor cells migrate into regions of tissue injury. They are unique in their expression of hematopoietic and monocyte lineage markers and extracellular matrix proteins. Several studies have focused on the specific role of fibrocytes in the process of wound repair and tissue regeneration. We discuss herein the biology and mechanistic action of fibrocytes in wound healing, scar formation, and maintenance of tissue integrity. Fibrocytes synthesize and secrete different cytokines, chemokines, and growth factors, providing a wound milieu that supports tissue repair. They further promote angiogenesis and contribute to wound closure via pathways involving specific cytokines, leukocyte-specific protein-1, serum amyloid P, and adenosine A(2A) receptors. Fibrocytes are involved in inflammatory fibrotic processes in such diseases as systemic fibrosis, atherosclerosis, asthma, hypertrophic scarring, and keloid formation. Accumulating literature has emphasized the important role of fibrocytes in wound healing and fibrosis. Detailed mechanisms nevertheless remain to be investigated to elucidate the full therapeutic potential of fibrocytes in the treatment of fibrosing disorders and the enhancement of tissue repair.

Role of semaphorin 7a signaling in transforming growth factor β1-induced lung fibrosis and scleroderma-related interstitial lung disease.

Abstract: The Semaphorins (Semas) are a family of highly conserved, secreted or membrane-bound proteins that are divided into eight classes based on primary sequence similarity and distinct structural features (1, 2). Semas are expressed on nerve, myeloid, and lymphoid cells, and they regulate immune responses as well as developmental processes related to organogenesis, angiogenesis, apoptosis, and neoplasia (3–5). Semaphorin 7a (Sema-7a), also called CDw108, is a GPI-anchored membrane protein that signals through at least two receptors: the β1-integrin subunit and Plexin C1 (1, 3). Sema-7a-mediated activation of β1-integrin enhances central and peripheral axonal growth and is requiredfor proper axonal tracking during embryonic development (4, 5), while Plexin C1 appears to inhibit some of these β1 integrin-mediated effects (3). Interactions between Sema-7a and its receptors also contribute to inflammation and immunity by stimulation of macrophage chemotaxis and cytokine production (6), regulation of dendritic cell migration and chemokine expression (4), modulation of T cell function (7), and regulation of melanocyte spreading and melanoma invasion (3, 8). Our recent studies advance the understanding of Sema-7a by demonstrating that it also plays an important role in the pathogenesis of transforming growth factor (TGF)-β1 induced inflammation and fibrosis (9). However, the mechanism(s) by which Sema-7a promotes these outcomes remains obscure. The CD14+ fraction of peripheral blood contains a heterogeneous group of monocyte progenitors with important roles in tissue injury and repair. A CD34+CD45+ subpopulation of CD14+ monocytes differentiates into fibrocytes by acquiring a fibroblast-like morphology and expressing collagens I and III (10). These events occur in a TGF-β1-dependent, PI3 kinase-dependent manner (11, 12), and over time, CD14 and CD34 expression may be down-regulated. Fibrocytes traffic into and accumulate in injured tissue in response to chemokines (13, 14), and their presence is associated with various fibrosing disorders including asthma, pulmonary fibrosis, and scleroderma (15–17). Interestingly, while Sema-7a is known to affect monocyte activation in vitro via β1 integrin mediated effects (6) the role of Sema-7a in the development of fibrocytes has not been assessed. Systemic sclerosis (SSc), or scleroderma, is a multisystem autoimmune disease characterized by progressive cutaneous and visceral fibrosis and over-activation of TGF-β1 signaling pathways (18, 19). Advances in the treatment of SSc-related renal disease have led to the emergence of pulmonary involvement as the greatest cause of mortality in SSc (20). The majority of patients with SSc demonstrate pathologic findings of interstitial lung disease (SSc-ILD) and show replacement of the normal lung parenchyma with inflamed and fibrotic tissue that is ineffective for gas exchange (21, 22). Up to 42% of patients with SSc-ILD will die of disease progression within ten years of diagnosis (20). Treatment with cyclophosphamide (23) or lymphocyte modulating agents (24, 25) show a modest benefit in delaying disease progression, but patients often relapse. The prevalence of gastroesophageal reflux disease (GERD) and ongoing autoimmunity in these patients frequently leads to poor outcomes following lung transplantation (26, 27). Thus, a better understanding of the pathogenesis of SSc-ILD may ameliorate the most frequent cause of death in these patients. We hypothesized that Sema-7a promotes TGF-β1-induced pulmonary fibrosis by stimulating the accumulation of intrapulmonary fibrocytes and that the β1 integrin subunit plays an important role in these responses. Fibrocytes have emerged as an important area of research in SSc-ILD (28). However immunologic factors regulating their accumulation remain obscure, and a role for Sema-7a has not been considered. We characterized the role of Sema-7a in fibrocyte accumulation in lung-targeted, TGF-β1 transgenic mice and defined the tissue compartment and molecular pathway through which Sema-7a exerts these effects. Our studies demonstrate that TGF-β1 induces fibrocyte accumulation in a Sema-7a dependent manner, that Sema-7a expression on bone marrow derived cells is sufficient for the induction of fibrosis and fibrocyte appearance, and that β1 integrin blockade ameliorates these responses. This signaling axis and pathway for fibrocyte activation exists in normal human cells and appears enhanced in patients with SSc-ILD.

Macrophage migration inhibitory factor regulates neutrophil chemotactic responses in inflammatory arthritis in mice.

Abstract: Objective Macrophage migration inhibitory factor (MIF) facilitates multiple aspects of inflammatory arthritis, the pathogenesis of which has been significantly linked to the activity of neutrophils. The effects of MIF on neutrophil recruitment are unknown. This study was undertaken to investigate the contribution of MIF to the regulation of neutrophil chemotactic responses. Methods K/BxN serum-transfer arthritis was induced in wild-type (WT), MIF−/−, and monocyte chemotactic protein 1 (MCP-1; CCL2)–deficient mice as well as in WT mice treated with monoclonal antibodies to cytokine-induced neutrophil chemoattractant (anti-KC). Leukocyte trafficking in vivo was examined using intravital microscopy, and neutrophil function in vitro was examined using migration chambers and assessment of MAP kinase activation. Results K/BxN serum-transfer arthritis was markedly attenuated in MIF−/− mice, with reductions in the clinical and histologic severity of arthritis and the synovial expression of KC and interleukin-1. Arthritis was also reduced by anti-KC antibody treatment, but not in MCP-1–deficient mice. In vivo, neutrophil recruitment responses to KC were reduced in MIF−/− mice. Similarly, MIF−/− mouse neutrophils exhibited reduced chemotactic responses to KC in vitro, despite displaying unaltered chemokine receptor expression. Reduced chemotactic responses of MIF−/− mouse neutrophils were associated with reduced phosphorylation of p38 and ERK MAP kinases. Conclusion These findings suggest that MIF promotes neutrophil trafficking in inflammatory arthritis via facilitation of chemokine-induced migratory responses and MAP kinase activation. Therapeutic MIF inhibition could limit synovial neutrophil recruitment.

Enhanced expression of receptor for advanced glycation end-products is associated with low circulating soluble isoforms of the receptor in Type 2 diabetes.

Abstract: The sRAGE [soluble RAGE (receptor for advanced glycation end-products)] lack the transmembrane and cytoplasmic domain of the full-length receptor and can function as a decoy for RAGE ligands. Recent evidence suggests that sRAGE may be a potential biomarker of RAGE-mediated pathology. The present study aimed to examine the relationship between RAGE expression in peripheral blood monocytes and circulating sRAGE and esRAGE (endogenous sRAGE, a splice variant of sRAGE) in Type 2 diabetes. Protein expression of RAGE and esRAGE in monocyte cell lysate was determined by Western blot in 53 diabetic patients and 52 controls. Monocyte cell-surface-bound full-length RAGE expression was measured using flow cytometry. Serum sRAGE, esRAGE and AGE (advanced glycation end products) were assayed by ELISA. The mean HbA1c (glycated haemoglobin) of the diabetic patients was 9.74 % and serum AGEs was increased. Monocyte full-length RAGE expression was significantly higher in diabetic patients whereas esRAGE expression was reduced, and serum AGEs concentration was an independent determinant of monocyte cell surface full-length RAGE expression. Serum levels of sRAGE [573.3 (375.7–754.3) compared with 608.1 (405.3–940.8) pg/ml, P < 0.05] and esRAGE [241.8 (154.6– 356.6) compared with 286.5 (202.6–390.0) pg/ml, P < 0.05; values are medians (interquartile range)] were decreased. There was an inverse association between monocyte RAGE expression and log(serum sRAGE) (r =− 0.34, P = 0.01) but not with esRAGE. In conclusion, despite an increase in full-length RAGE expression, esRAGE expression was down-regulated in the diabetic patients, and serum sRAGE and esRAGE was also reduced. Hence increased full-length RAGE levels are not associated with a similar increase in sRAGE isoforms levels.

Critical role for macrophage migration inhibitory factor (MIF) in Ross River virus-induced arthritis and myositis

Abstract: Arthrogenic alphaviruses, such as Ross River virus (RRV), chikungunya, Sindbis, mayaro and o'nyong-nyong viruses circulate endemically worldwide, frequently causing outbreaks of polyarthritis. The exact mechanisms of how alphaviruses induce polyarthritis remain ill defined, although macrophages are known to play a key role. Macrophage migration inhibitory factor (MIF) is an important cytokine involved in rheumatoid arthritis pathogenesis. Here, we characterize the role of MIF in alphavirus-induced arthritides using a mouse model of RRV-induced arthritis, which has many characteristics of RRV disease in humans. RRV-infected WT mice developed severe disease associated with up-regulated MIF expression in serum and tissues, which corresponded to severe inflammation and tissue damage. MIF-deficient (MIF(-/-)) mice developed mild disease accompanied by a reduction in inflammatory infiltrates and muscle destruction in the tissues, despite having viral titers similar to WT mice. In addition, reconstitution of MIF into MIF(-/-) mice exacerbated RRV disease and treatment of mice with MIF antagonist ameliorated disease in WT mice. Collectively, these findings suggest that MIF plays a critical role in determining the clinical severity of alphavirus-induced musculoskeletal disease and may provide a target for the development of antiviral pharmaceuticals. The prospect being that early treatment with MIF-blocking pharmaceuticals may curtail the debilitating arthritis associated with alphaviral infections.

Local apoptosis promotes collagen production by monocyte-derived cells in transforming growth factor β1-induced lung fibrosis

Abstract: Background Collagen-containing leukocytes (CD45+Col-I+) accumulate in diseased and fibrotic tissues. However, the precise identity of these cells and whether injury is required for their recruitment remain unknown. Using a murine model of pulmonary fibrosis in which an inducible, bioactive form of the human transforming growth factor (TGF)-β1 gene is targeted to the lung, we characterized the cell surface phenotype of collagen-containing CD45+ cells in the lung and tested the hypothesis that apoptotic cell death responses are essential to the accumulation of CD45+Col-I+ cells.

A role for the B‐cell CD74/macrophage migration inhibitory factor pathway in the immunomodulation of systemic lupus erythematosus by a therapeutic tolerogenic peptide

Abstract: Systemic lupus erythematosus (SLE) is an autoimmune disease that involves dysregulation of B and T cells A tolerogenic peptide, designated hCDR1, ameliorates disease manifestations in SLE-afflicted mice In the present study, the effect of treatment with hCDR1 on the CD74/macrophage migration inhibitory factor (MIF) pathway was studied We report here that B lymphocytes from SLE-afflicted mice express relatively elevated levels of CD74, compared with B cells from healthy mice CD74 is a receptor found in complex with CD44, and it binds the pro-inflammatory cytokine MIF The latter components were also up-regulated in B cells from the diseased mice, and treatment with hCDR1 resulted in their down-regulation and in reduced B-cell survival Furthermore, up-regulation of CD74 and CD44 expression was detected in brain hippocampi and kidneys, two target organs in SLE Treatment with hCDR1 diminished the expression of those molecules to the levels determined for young healthy mice These results suggest that the CD74/MIF pathway plays an important role in lupus pathology

Lack of macrophage migration inhibitory factor in mice does not affect hallmarks of the inflammatory/immune response during the first week after stroke

Abstract: Macrophage migration inhibitory factor (MIF) has been proposed to play a detrimental role in stroke. We recently showed that MIF promotes neuronal death and aggravates neurological deficits during the first week after experimental stroke, in mice. Since MIF regulates tissue inflammation, we studied the putative role of MIF in post-stroke inflammation. We subjected C57BL/6 mice, Mif -/- (MIF-KO) or Mif +/+ (WT), to a transient occlusion of the right middle cerebral artery (tMCAo) or sham-surgery. We studied MIF expression, GFAP expression and the number of CD74-positive cells in the ischemic brain hemisphere 7 days after tMCAo using primarily immunohistochemistry. We determined IFN-γ, IL-2, IL-4, IL-5, IL-10, IL-12, KC/CXCL-1 and TNF-α protein levels in the brain (48 h after surgery) and serum (48 h and 7 days after surgery) by a multiplex immunoassay. We observed that MIF accumulates in neurons and astrocytes of the peri-infarct region, as well as in microglia/macrophages of the infarct core up to 7 days after stroke. Among the inflammatory mediators analyzed, we found a significant increase in cerebral IL-12 and KC levels after tMCAo, in comparison to sham-surgery. Importantly, the deletion of Mif did not significantly affect the levels of the cytokines evaluated, in the brain or serum. Moreover, the spleen weight 48 h and 7 days subsequent to tMCAo was similar in WT and MIF-KO mice. Finally, the extent of GFAP immunoreactivity and the number of MIF receptor (CD74)-positive cells within the ischemic brain hemisphere did not differ significantly between WT and MIF-KO mice subjected to tMCAo. We conclude that MIF does not affect major components of the inflammatory/immune response during the first week after experimental stroke. Based on present and previous evidence, we propose that the deleterious MIF-mediated effects in stroke depend primarily on an intraneuronal and/or interneuronal action.

Elevated Levels of Macrophage Migration Inhibitory Factor in Women with Metabolic Syndrome

Abstract: Metabolic syndrome is a complex clinical disorder characterized by obesity, a disturbance of glucose metabolism, dyslipidemia, and hypertension, leading to increased cardiovascular risk. Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine produced both by innate immune cells and by adipocytes, and it plays an important role in inflammatory and cardiovascular diseases. The goal of this study was to evaluate the expression of circulating MIF in patients with metabolic syndrome. A study was conducted involving 172 persons who attended the Jeju National University Hospital Health Promotion Center. Among the 172 subjects, 88 patients with metabolic syndrome and 84 healthy control subjects were included. Serum MIF levels were considerably higher in patients with metabolic syndrome than in healthy subjects (mean±SEM, 1413.0-pg/ml±102.6 vs. 1077.0-pg/ml±-91.3, p=0.016). Among the metabolic syndrome patients, MIF levels were significantly increased in women (1403.0-pg/ml±114.2 vs. 921.3pg/ml±117.3, p=0.005), but not in men. Even after further linear regression adjustment for age and body mass index, the expression of MIF for women with metabolic syndrome was still clearly elevated when compared to healthy subjects (p=0.011). Circulating MIF concentrations showed a gender disparity between healthy and metabolic syndrome subjects. An elevation of systemic MIF in women with metabolic syndrome may contribute to pathogenesis of metabolic syndrome or to the development of metabolic syndrome-related diseases, such as atherosclerosis and type 2 diabetes mellitus.

Role of Macrophage Migration Inhibitory Factor in the Th2 Immune Response to Epicutaneous Sensitization

Abstract: We examined the role of macrophage migration inhibitory factor (MIF) in the generation of the Th2 response using MIF-deficient mice in a model of epicutaneous sensitization to ovalbumin. Lymph node cells from sensitized MIF-deficient mice produce lower levels of Th2 cytokines after antigen challenge when compared to their wild-type counterparts. Sensitized mice lacking MIF show less pulmonary inflammation after intranasal antigen exposure. Mice deficient in CD74, the MIF receptor, also are unable to generate an inflammatory response to epicutaneous sensitization. Examination of the elicitation phase of the atopic response using DO11.10 OVA TCR transgenic animals shows that T cell proliferation and IL-2 production are strongly impaired in MIF-deficient T cells. This defect is most profound when both T cells and antigen-presenting cells are lacking MIF. These data suggest that MIF is crucial both for the sensitization and the elicitation phases of a Th2-type immune response in allergic disease.

Macrophage migration inhibitory factor: a downregulator of early T cell-dependent IFN-gamma responses in Plasmodium chabaudi adami (556 KA)-infected mice.

Abstract: Neutralization of macrophage migration inhibitory factor (MIF) increases anti-tumor cytotoxic T cell responses in vivo and IFN-γ responses in vitro, suggesting a plausible regulatory role for MIF in T cell activation. Considering that IFN-γ production by CD4(+) T cells is pivotal to resolve murine malaria and that secretion of MIF is induced by Plasmodium chabaudi adami parasites, we investigated the effect of MIF deficiency on the infection with this pathogen. Infections with P. c. adami 556 KA parasites were more efficiently controlled in MIF-neutralized and MIF-deficient (knockout [KO]) BALB/c mice. The reduction in parasitemia was associated with reduced production of IL-4 by non-T/non-B cells throughout patent infection. At day 4 postinfection, higher numbers of activated CD4(+) cells were measured in MIF KO mice, which secreted more IFN-γ, less IL-4, and less IL-10 than did CD4(+) T cells from wild-type mice. Enhanced IFN-γ and decreased IL-4 responses also were measured in MIF KO CD4(+) T cells stimulated with or without IL-12 and anti-IL-4 blocking Ab to induce Th1 polarization. However, MIF KO CD4(+) T cells efficiently acquired a Th2 phenotype when stimulated in the presence of IL-4 and anti-IL-12 Ab, indicating normal responsiveness to IL-4/STAT6 signaling. These results suggest that by promoting IL-4 responses in cells other than T/B cells during early P. c. adami infection, MIF decreases IFN-γ secretion in CD4(+) T cells and, additionally, has the intrinsic ability to render CD4(+) T cells less capable of acquiring a robust Th1 phenotype when stimulated in the presence of IL-12.

Compositions and methods for diagnosing and treating diseases and disorders associated with d-dt

Abstract: The present invention relates to the discovery that altered levels of D- DT (also known as MIF-2) are associated with disorders and diseases. Thus, the present invention relates to compositions and methods useful of the assessment, diagnosis, characterization, prevention and treatment of disorders and diseases associated with an elevated level of D-DT, The present invention also relates to compositions and methods useful of the assessment, diagnosis, characterization, prevention and treatment of disorders and diseases associated with a reduced level of D-DT.

Intersecting roads to rheumatoid arthritis.

Abstract: Rheumatoid arthritis (RA) occurs worldwide and affects all ethnic groups, albeit with varying incidence and severity. Over the last decade, there have been remarkable advances in our understanding of the pathogenesis of rheumatoid inflammation and in the application of new therapies. Our knowledge of the molecular pathways leading to immune activation, chronic joint inflammation, and local tissue destruction continues to increase; yet, while we have come to recognize common genetic and immunologic factors that contribute to disease, no single factor appears causative, and a cure for RA is still beyond our reach. Nosology remains fundamental to the investigation of clinical autoimmunity. Current pathogenic models of RA emphasize the development of a systemic immunologic abnormality, which may be incipient or genetically predetermined, that drives a sustained and tissue-destructive synovial inflammatory response. It is hypothesized that autoimmune triggers lead to the selfperpetuating activation of several arms of the immune system, involving neutrophils, dendritic cells, monocyte/ macrophages, and B and T lymphocytes (1). As a consequence of rheumatoid joint inflammation, the synovium develops into granulation tissue known as pannus, and the fibroblast-like synovial lining cells acquire a continuously activated state, show enhanced proliferation, and secrete high levels of growth factors and matrix-degrading enzymes that promote cartilage and bone erosion. Such properties endure in synovial fibroblasts in vitro, suggesting that these cells are persistently altered in the rheumatoid joint (2). Rheumatoid synovial fibroblasts have been shown to proliferate in an anchorage-independent manner, escape contact inhibition, form microfoci, and invade cartilage implants when engrafted into immunodeficient mice (3). Precisely how synovial fibroblasts acquire this long-term activated state after their removal from the RA milieu is unknown, but it may be the result of a re-entrant pathway involving autocrine mediators and mutually reinforcing signal transduction pathways. There is evidence in rheumatoid synovial fibroblasts of sustained activation of protooncogene expression and of the functional inactivation of the tumor suppressor gene p53, which regulates cell cycle progression. Regardless of the precise effector pathways that contribute to this persistent phenotype, immune/inflammatory stimuli play a critical role in the initiation and the perpetuation of the invasive and pro-proliferative properties of rheumatoid synoviocytes (4). Investigations of arthritis pathogenesis in humans suffer from severe practical limitations; beyond the identification of susceptibility and disease-modifying genes, an examination of the interplay of the early pathogenic events that lead to the clinical expression of autoimmunity is extremely difficult. Accordingly, animal models of RA continue to hold center stage in formulating our pathologic conception of rheumatoid inflammation, and they have proved useful in delineating the molecular features that underlie both immune abnormalities and the specific effector mechanisms that produce joint destruction. Mouse models in particular, given the ease by which precise genetic deletions may be created and studied, have been especially informative in identifying or validating candidate disease-causative or disease-modifying factors (5). Among such studies, genetic definition of transcription activators (i.e. proteins that bind to DNA regulatory sequences to regulate gene induction) have been invaluable for understanding the mechanisms by which immune signals, for instance, those triggered by antigen receptors or cytokines, initiate the network of responses that characterize rheumatoid inflammation (6). Bioinformatics, which relies on computational assistance to analyze many thousands of gene expression Dr. Bucala’s work was supported by the NIH. Richard Bucala, MD, PhD: Yale University School of Medicine, New Haven, Connecticut. Address correspondence to Richard Bucala, MD, PhD, Department of Medicine, Section of Rheumatology, The Anlyan Center, Suite 525, Yale University School of Medicine, 300 Cedar Street, New Haven, CT 06520. E-mail: Richard.Bucala@Yale.edu. Submitted for publication November 15, 2010; accepted in revised form December 28, 2010.

Methods of administering D-dopachrome tautomerase (D-DT) to treat ischemia-reperfusion injury

Abstract: The present invention relates to the discovery that reduced levels of D-dopachrome tautomerase (D-DT) (also known as MIF-2) are associated with ischemia-reperfusion injury. Thus, the present invention relates to methods of administering D-DT and recombinant D-DT for the treatment of ischemia-reperfusion injury.