Cytokine Macrophage Migration Inhibitory Factor Research Articles

Evaluation of the potential therapeutic benefits of macrophage reprogramming in multiple myeloma

AbstractTumor-associated macrophages (TAM) are important components of the multiple myeloma (MM) microenvironment that support malignant plasma cell survival and resistance to therapy. It has been proposed that macrophages (MØ) retain the capacity to change in response to stimuli that can restore their antitumor functions. Here, we investigated several approaches to reprogram MØ as a novel therapeutic strategy in MM. First, we found tumor-limiting and tumor-supporting capabilities for monocyte-derived M1-like MØ and M2-like MØ, respectively, when mixed with MM cells, both in vitro and in vivo. Multicolor confocal microscopy revealed that MM-associated MØ displayed a predominant M2-like phenotype in the bone marrow of MM patient samples, and a high expression of the pro-M2 cytokine macrophage migration inhibitory factor (MIF). To reprogram the protumoral M2-like MØ present in MM toward antitumoral M1-like MØ, we tested the pro-M1 cytokine granulocyte–macrophage colony-stimulating factor (GM-CSF) plus blockade of the M2 cytokines macrophage colony-stimulating factor or MIF. The combination of GM-CSF plus the MIF inhibitor 4-iodo-6-phenyl-pyrimidine achieved the best reprogramming responses toward an M1 profile, at both gene and protein expression levels, as well as remarkable tumoricidal effects. Furthermore, this combined treatment elicited MØ-dependent therapeutic responses in MM xenograft mouse models, which were linked to upregulation of M1 and reciprocal downregulation of M2 MØ markers. Our results reveal the therapeutic potential of reprogramming MØ in the context of MM.

MIF-driven activation of macrophages induces killing of intracellular Trypanosoma cruzi dependent on endogenous production of tumor necrosis factor, nitric oxide and reactive oxygen species

The proinflammatory cytokine macrophage migration inhibitory factor (MIF) is a key player in innate immunity. MIF has been considered critical for controlling acute infection by the protozoan Trypanosoma cruzi, but the underlying mechanisms are poorly understood. Our study aimed to analyze whether MIF could favor microbicidal activity of the macrophage, a site where T. cruzi grows and the initial effector cell against this parasite. Using murine macrophages infected in vitro, we examined the effect of MIF on their parasiticidal ability and attempted to identify inflammatory agents involved in MIF-induced protection. Our findings show that MIF is readily secreted from peritoneal macrophages upon T. cruzi infection. MIF activates both primary and J774 phagocytes boosting the endogenous production of tumor necrosis factor-alpha via mitogen-activated protein kinase p38 signaling, as well as the release of nitric oxide and reactive oxygen species, leading to enhanced pathogen elimination. MIF can also potentiate the effect of interferon-gamma on T. cruzi killing by J774 and mouse peritoneal macrophages, rendering these cells more competent in reducing intracellular parasite burden. The present results unveil a novel innate immune pathway that contributes to host defense and broaden our understanding of the regulation of inflammatory mediators implicated in early parasite containment that is decisive for resistance to T. cruzi infection.

Dengue Virus Nonstructural Protein 1 Induces Vascular Leakage through Macrophage Migration Inhibitory Factor and Autophagy.

Dengue virus (DENV) is the most common mosquito-borne flavivirus; it can either cause mild dengue fever or the more severe dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). One of the characteristic features of DHF/DSS is vascular leakage; although DENV nonstructural protein 1 (NS1) has been proved to induce vascular leakage after binding to Toll-like receptor 4, the down-stream mechanism has not yet been fully understood. In the sera of DENV-infected patients, the concentrations of DENV NS1 and inflammatory cytokine macrophage migration inhibitory factor (MIF) are positively correlated with disease severity, but whether DENV NS1 induces vascular leakage through MIF secretion remains unknown. We demonstrated that recombinant NS1 induced vascular leakage and MIF secretion both in human endothelial cell line HMEC-1 and in mice. Furthermore, these phenomena were inhibited in the presence of anti-NS1 antibodies both in vitro and in vivo. DENV NS1 also induced LC3-I to LC3-II conversion and p62 degradation in endothelial cell line, which indicated the formation of autophagy. To clarify whether MIF or autophagy mediated DENV NS1-induced vascular leakage, various inhibitors were applied. The results showed that DENV NS1-induced vascular leakage and VE-cadherin disarray were blocked in the presence of MIF inhibitors, anti-MIF-antibodies or autophagy inhibitors. An Atg5 knockdown clone further confirmed that autophagy formation of endothelial cells was required in NS1-induced vascular leakage. Furthermore, DENV NS1-induced LC3 puncta were also decreased in the presence of MIF inhibitors, indicating that MIF mediated DENV NS1-induced autophagy. Taken together, the results suggest a potential mechanism of DENV-induced vascular leakage and provide possible therapeutic targets against DHF/DSS.

The clinical significance of the MIF homolog d-dopachrome tautomerase (MIF-2) and its circulating receptor (sCD74) in burn

BackgroundWe reported earlier that the cytokine macrophage migration inhibitory factor (MIF) is a potential biomarker in burn injury. In the present study, we investigated the clinical significance of the newly discovered MIF family member d-dopachrome tautomerase (DDT or MIF-2) and their common soluble receptor CD74 (sCD74) in severely burned patients. MethodsDDT and sCD74 serum levels were measured 20 severely burned patients and 20 controls. Serum levels were correlated to the abbreviated burn severity index (ABSI) and total body surface area (TBSA) followed by receiver operating characteristic (ROC) analysis. Data were supported by gene expression dataset analysis of 31 burn patients and 28 healthy controls. ResultsCD74 and DDT were increased in burn patients. Furthermore, CD74 and DDT also were elevated in septic non-survivors when compared to survivors. Serum levels of DDT showed a positive correlation with the ABSI and TBSA in the early stage after burn, and the predictive character of DDT was strongest at 24h. Serum levels of CD74 only correlated with the ABSI 5 days after injury. ConclusionsDDT may assist in the monitoring of clinical outcome and prediction of sepsis during the early post-burn period. Soluble CD74 and MIF, by contrast, have limited value as an early predictor of death due to their delayed response to burn.

MIF-CD74 signaling impedes microglial M1 polarization and facilitates brain tumorigenesis.

Microglial cells in the brain tumor microenvironment are associated with enhanced glioma malignancy. They persist in an immunosuppressive M2 state at the peritumoral site and promote the growth of gliomas. Here, we investigated the underlying factors contributing to the abolished immune surveillance. We show that brain tumors escape pro-inflammatory M1 conversion of microglia via CD74 activation through the secretion of the cytokine macrophage migration inhibitory factor (MIF), which results in a M2 shift of microglial cells. Interruption of this glioma-microglial interaction through an antibody-neutralizing approach or small interfering RNA (siRNA)-mediated inhibition prolongs survival time in glioma-implanted mice by reinstating the microglial pro-inflammatory M1 function. We show that MIF-CD74 signaling inhibits interferon (IFN)-γ secretion in microglia through phosphorylation of microglial ERK1/2 (extracellular signal-regulated protein kinases 1 and 2). The inhibition of MIF signaling or its receptor CD74 promotes IFN-γ release and amplifies tumor death either through pharmacological inhibition or through siRNA-mediated knockdown. The reinstated IFN-γ secretion leads both to direct inhibition of glioma growth as well as inducing a M2 to M1 shift in glioma-associated microglia. Our data reveal that interference with the MIF signaling pathway represents a viable therapeutic option for the restoration of IFN-γ-driven immune surveillance.

Endothelial Cell Secreted MIF Regulates Pericyte Contractility to Decrease Barrier Function

Microvascular endothelial cells (EC) and pericytes (PC) regulate neutrophil (PMN) transmigration through a variety of mechanisms, including adhesion molecule expression and contractility. Specifically, the contraction of endothelial cells creates F‐actin docking structures rich in intercellular adhesion molecule 1 (ICAM‐1) expression and generates gaps between cells that allow for PMN transmigration. Recent evidence has alternatively suggested that PC relaxation, rather than contractility, results in the loss of focal adhesions, disassembly of stress fibers, and subsequent increase in PMN transmigration. Both in vivo and in vitro experimental systems of composite EC/PC microvascular constructs demonstrate that PC are less permissive to neutrophil transmigration in the absence of EC, suggesting that communication between EC and PC may regulate PC contractility. Here, we demonstrate that tumor necrosis factor alpha (TNFa) induced EC secretion of the pro‐inflammatory cytokine macrophage migration inhibitory factor (MIF), which is accompanied by a TNFa induced upregulation of the MIF receptor (CD74) in PC, significantly decreases PC contractility. We confirm that TNFa mediated transmigration is differentially regulated by contractility. EC contractile ability is required to facilitate PMN transmigration through the formation of F‐actin docking sites and ICAM‐1 localization. In contrast, inhibition of PC contractility increases PMN transmigration via mechanisms that are not related to the loss of ICAM‐1 localization and F‐actin disassembly, but rather the loss of focal adhesion plaques, the loss of tension fibers and the formation of PC junctional gaps. We have confirmed that EC secreted MIF signaling results in the loss of PC focal adhesion plaques and significantly decreases PC contractility. This study suggests for the first time that EC paracrine signaling can mediate PC regulated PMN transmigration, and specifically that EC to PC MIF signaling may be an important factor for reducing PC barrier function during inflammation.Support or Funding InformationDubinsky Initiative

Identification of a novel miR-146a from Pinctada martensii involved in the regulation of the inflammatory response.

Increasing evidence demonstrated that microRNAs (miRNAs) play critical roles in innate immunity in vertebrates and invertebrates. MiR-146a/b is reported as a key regulator of the immune response through mediating Toll-like receptor and cytokine signalling. In this study, a novel miR-146a was identified and characterised from Pinctada martensii (designated as pm-miR-146a), and its roles in modulating the inflammatory response after LPS stimulation were also investigated. Pm-miR-146a ubiquitously expressed in all examined tissues, with the highest level in the mantle and lowest expression in the haemolymph. Pm-miR-146a increased at 24h after lipoplysaccharide injection, in union with up-regulated NF-κB (P<0.05). The over-expression of pm-miR-146a invivo could significantly inhibit the expression of macrophage migration inhibitory factor (MIF), the potential target gene predicted by miRanda, while enforcing pm-miR-146a involved in the down-regulation of NF-κB. Thus, we propose that pm-miR-146a plays a role of negative feedback regulation to the NF-κB signal by repressing the expression of the pro-inflammatory cytokine MIF. These findings revealed that miR-146a represents a critical role in inflammatory response and offers new evidence for miRNAs in the innate immunity of molluscs.

Leishmania-encoded orthologs of macrophage migration inhibitory factor regulate host immunity to promote parasite persistence.

Leishmania major encodes 2 orthologs of the cytokine macrophage migration inhibitory factor (MIF), whose functions in parasite growth or in the host-parasite interaction are unknown. To determine the importance of Leishmania-encoded MIF, both LmMIF genes were removed to produce an mif(-/-) strain of L. major This mutant strain replicated normally in vitro but had a 2-fold increased susceptibility to clearance by macrophages. Mice infected with mif(-/-) L. major, when compared to the wild-type strain, also showed a 3-fold reduction in parasite burden. Microarray and functional analyses revealed a reduced ability of mif(-/-) L. major to activate antigen-presenting cells, resulting in a 2-fold reduction in T-cell priming. In addition, there was a reduction in inflammation and effector CD4 T-cell formation in mif(-/-) L. major-infected mice when compared to mice infected with wild-type L. major Notably, effector CD4 T cells that developed during infection with mif(-/-) L. major demonstrated statistically significant differences in markers of functional exhaustion, including increased expression of IFN-γ and IL-7R, reduced expression of programmed death-1, and decreased apoptosis. These data support a role for LmMIF in promoting parasite persistence by manipulating the host response to increase the exhaustion and depletion of protective CD4 T cells.-Holowka, T., Castilho, T. M., Baeza Garcia, A., Sun, T., McMahon-Pratt, D., Bucala, R. Leishmania-encoded orthologs of macrophage migration inhibitory factor regulate host immunity to promote parasite persistence.

Macrophage Migration Inhibitory Factor (MIF) Deficiency Exacerbates Aging-Induced Cardiac Remodeling and Dysfunction Despite Improved Inflammation: Role of Autophagy Regulation.

Aging leads to unfavorable geometric and functional sequelae in the heart. The proinflammatory cytokine macrophage migration inhibitory factor (MIF) plays a role in the maintenance of cardiac homeostasis under stress conditions although its impact in cardiac aging remains elusive. This study was designed to evaluate the role of MIF in aging-induced cardiac anomalies and the underlying mechanism involved. Cardiac geometry, contractile and intracellular Ca2+ properties were examined in young (3–4 mo) or old (24 mo) wild type and MIF knockout (MIF−/−) mice. Our data revealed that MIF knockout exacerbated aging-induced unfavorable structural and functional changes in the heart. The detrimental effect of MIF knockout was associated with accentuated loss in cardiac autophagy with aging. Aging promoted cardiac inflammation, the effect was attenuated by MIF knockout. Intriguingly, aging-induced unfavorable responses were reversed by treatment with the autophagy inducer rapamycin, with improved myocardial ATP availability in aged WT and MIF−/− mice. Using an in vitro model of senescence, MIF knockdown exacerbated doxorubicin-induced premature senescence in H9C2 myoblasts, the effect was ablated by MIF replenishment. Our data indicated that MIF knockout exacerbates aging-induced cardiac remodeling and functional anomalies despite improved inflammation, probably through attenuating loss of autophagy and ATP availability in the heart.

Editorial: The CXCR4 Ligand/Receptor Family and the DPP4 Protease in High-Risk Cardiovascular Patients.

The Editorial on the Research Topic The CXCR4 Ligand/Receptor Family and the DPP4 Protease in High-Risk Cardiovascular Patients Cardiovascular disease (CVD) is the most common cause of morbidity and mortality worldwide and was responsible for 17.5 million deaths in 2012. This equals 31% of all deaths globally and is almost double the amount of cancer-related deaths (1). Although CVD encompasses a broad range of pathologic conditions, 80% of all CVD-related deaths are due to heart attacks and stroke (1). An important underlying pathology is atherosclerosis, a chronic inflammatory state of the arterial wall that is characterized by lipid deposition, dysfunction of the endothelium, and infiltration of inflammatory cells into the vessel wall, resulting in the development of atherosclerotic lesions (2). Type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) have been identified as important risk factors for CVD. Fifty percent of patients with CKD stages 4–5 suffer from CVD (3), and cardiovascular mortality accounts for ~40–50% of all deaths in these patients, compared with 26% in controls with normal kidney function (4, 5). Also in patients with diabetes, CVD accounts for at least 50% of deaths (6). With currently around 10–13% of people presenting with CKD and more than 8% of adults suffering from diabetes (6–8), the social and economic burden of diabetes, CKD, and CVD is extremely high. Thus, a better understanding of the mechanisms contributing to and mediating the interplay between T2DM, CKD, and CVD is required to improve the prevention and treatment of these diseases. In this Research Topic, we focus on the classical CXC chemokine receptor CXCR4 (9), its cognate ligand CXCL12 (10), and the chemokine-like cytokine macrophage migration inhibitory factor (MIF), which functions as a non-cognate ligand of CXCR4 (11), in the context of CVD. An emphasis is made on links with T2DM and CKD. Also, we discuss dipeptidyl peptidase-4 (DPP4) as an important protease known to destabilize CXCL12 and thus to influence signaling through the CXCL12/CXCR4 axis. Chemokines and their receptors are important mediators of cell mobilization, recruitment and arrest, and additionally more broadly induce cell activation by triggering various intracellular signaling tracks. Chemokines control basic homeostatic conditions but are also critically involved in inflammatory processes, e.g., in atherosclerosis (12, 13). Genome-wide association studies revealed single nucleotide polymorphisms connecting CXCL12 as well as MIF with CVD (2, 14–19), and a role for both of these mediators in T2DM and CKD has been reported. In this Research Topic, we introduce the reader to the comorbidities T2DM and CKD and their connection with CVD, and provide up-to-date information on the involvement of CXCL12/MIF/CXCR4 and DPP4 in each of these pathologies. One focus is laid upon providing insight on mechanistic level.

Cell surface syndecan-1 contributes to binding and function of macrophage migration inhibitory factor (MIF) on epithelial tumor cells

Surface expressed proteoglycans mediate the binding of cytokines and chemokines to the cell surface and promote migration of various tumor cell types including epithelial tumor cells. We here demonstrate that binding of the chemokine-like inflammatory cytokine macrophage migration inhibitory factor (MIF) to epithelial lung and breast tumor cell lines A549 and MDA-MB231 is sensitive to enzymatic digestion of heparan sulphate chains and competitive inhibition with heparin. Moreover, MIF interaction with heparin was confirmed by chromatography and a structural comparison indicated a possible heparin binding site. These results suggested that proteoglycans carrying heparan sulphate chains are involved in MIF binding. Using shRNA-mediated gene silencing, we identified syndecan-1 as the predominant proteoglycan required for the interaction with MIF. MIF binding was decreased by induction of proteolytic shedding of syndecan-1, which could be prevented by inhibition of the metalloproteinases involved in this process. Finally, MIF induced the chemotactic migration of A549 cells, wound closure and invasion into matrigel without affecting cell proliferation. These MIF-induced responses were abrogated by heparin or by silencing of syndecan-1. Thus, our study indicates that syndecan-1 on epithelial tumor cells promotes MIF binding and MIF-mediated cell migration. This may represent a relevant mechanism through which MIF enhances tumor cell motility and metastasis.

MIF reflects tissue damage rather than inflammation in post-cardiac arrest syndrome in a real life cohort

IntroductionFollowing successful resuscitation from cardiac arrest (CA), neurological impairment and other types of organ dysfunction cause significant morbidity and mortality—a condition termed post-cardiac arrest syndrome. Whole-body ischemia/reperfusion with oxygen debt activates immunologic and coagulation pathways increasing the risk of multiple organ failure and infection. We here examined the role of the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF) in post-cardiac arrest syndrome. MethodsMIF plasma levels of n=16 patients with return of spontaneous circulation (ROSC) after CA were assessed with a previously validated method and compared to markers of systemic inflammation and cellular damage. ICU patients without former CA and healthy volunteers served as controls. ResultsMIF levels in patients after ROSC were higher compared to those in healthy volunteers and ICU patients without CA. Kaplan–Meyer analysis revealed a distinctly elevated mortality since day one that further increased towards an elevated 60-days-mortality in patients with high plasma MIF. ROC curve identified plasma MIF as a predictor for mortality in patients after CA. Correlation with inflammatory parameters revealed that high MIF levels did not mirror post CA inflammatory syndrome, but distinctive cellular damage after ROSC as there were strong correlations with markers of cellular damage like LDH and GOT/GPT. ConclusionHigh MIF levels were associated with elevated 60-days-mortality and high MIF predicted mortality after CA. We found a close relation between circulating MIF levels and cellular damage, but not with an inflammatory syndrome.

Transcription factor ICBP90 regulates the MIF promoter and immune susceptibility locus.

The immunoregulatory cytokine macrophage migration inhibitory factor (MIF) is encoded in a functionally polymorphic locus that is linked to the susceptibility of autoimmune and infectious diseases. The MIF promoter contains a 4-nucleotide microsatellite polymorphism (-794 CATT) that repeats 5 to 8 times in the locus, with greater numbers of repeats associated with higher mRNA levels. Because there is no information about the transcriptional regulation of these common alleles, we used oligonucleotide affinity chromatography and liquid chromatography-mass spectrometry to identify nuclear proteins that interact with the -794 CATT5-8 site. An analysis of monocyte nuclear lysates revealed that the transcription factor ICBP90 (also known as UHRF1) is the major protein interacting with the MIF microsatellite. We found that ICBP90 is essential for MIF transcription from monocytes/macrophages, B and T lymphocytes, and synovial fibroblasts, and TLR-induced MIF transcription is regulated in an ICBP90- and -794 CATT5-8 length-dependent manner. Whole-genome transcription analysis of ICBP90 shRNA-treated rheumatoid synoviocytes uncovered a subset of proinflammatory and immune response genes that overlapped with those regulated by MIF shRNA. In addition, the expression levels of ICBP90 and MIF were correlated in joint synovia from patients with rheumatoid arthritis. These findings identify ICBP90 as a key regulator of MIF transcription and provide functional insight into the regulation of the polymorphic MIF locus.

Macrophage migration inhibitory factor modulates formalin induced behaviors in rats

Cytokine proteins are involved in different signaling pathways throughout the central nervous system. To study the efficacy of an inflammatory cytokine, the macrophage migration inhibitory factor (MIF), which acts via several receptor molecules including the receptor CXCR2, male rats’ behaviors were determined after intracerebroventricular (ICV) administration of MIF. There were three treatments: One group received only the cytokine, a second group received MIF and an CXCR2 antagonist (SB265610), and a third, control group received only the carrier medium saline. All rats were subjected to a subcutaneous injection of formalin in the hind paw after the ICV administration. Pain behaviors induced after formalin injection showed increased values in the MIF group of licking in the first phase and increased values of flexing, licking and paw-jerk in the second phase. On the contrary, spontaneous behaviors induced by formalin injection changed alternatively between the two groups compared with saline. These results suggest a possible effect of cytokine MIF on central nervous processes implicated in pain modulation mediated by the receptor CXCR2.

Estrogen-dependent up-regulation of TRPA1 and TRPV1 receptor proteins in the rat endometrium.

Transient receptor potential ankyrin 1 (TRPA1) and vanilloid 1 (TRPV1) receptors expressed predominantly in sensory nerves are activated by inflammatory stimuli and mediate inflammation and pain. Although they have been shown in the human endometrium, their regulation and function are unknown. Therefore, we investigated their estrogen- and progesterone-dependent alterations in the rat endometrium in comparison with the estrogen-regulated inflammatory cytokine macrophage migration inhibitory factor (MIF). Four-week-old (sexually immature) and four-month-old (sexually mature) female rats were treated with the non-selective estrogen receptor (ER) agonist diethylstilboestrol (DES), progesterone and their combination, or ovariectomized. RT-PCR and immunohistochemistry were performed to determine mRNA and protein expression levels respectively. Channel function was investigated with ratiometric [Ca(2+)]i measurement in cultured primary rat endometrial cells. Both TRP receptors and MIF were detected in the endometrium at mRNA and protein levels, and their localizations were similar. Immunostaining was observed in the immature epithelium, while stromal, glandular and epithelial positivity were observed in adults. Functionally active TRP receptor proteins were shown in endometrial cells by activation-induced calcium influx. In adults, Trpa1 and Trpv1 mRNA levels were significantly up-regulated after DES treatment. TRPA1 increased after every treatment, but TRPV1 remained unchanged following the combined treatment and ovariectomy. In immature rats, DES treatment resulted in increased mRNA expression of both channels and elevated TRPV1 immunopositivity. MIF expression changed in parallel with TRPA1/TRPV1 in most cases. DES up-regulated Trpa1, Trpv1 and Mif mRNA levels in endometrial cell cultures, but 17β-oestradiol having ERα-selective potency increased only the expression of Trpv1. We provide the first evidence for TRPA1/TRPV1 expression and their estrogen-induced up-regulation in the rat endometrium in correlation with the MIF.

Single nucleotide polymorphisms in cytokine MIF gene promoter region are closely associated with human susceptibility to tuberculosis in a southwestern province of China

The gene encoding macrophage migration inhibitory factor (MIF) has been proposed as candidate tuberculosis (TB) susceptibility gene. In order to elucidate whether MIF gene variants are associated with susceptibility to retreatment cases of TB, and prevent drug-resistant TB prevalence, we conducted a study based on paired human population data. MIF −173 G/C single nucleotide polymorphisms (rs755622) were genotyped using polymerase chain reaction-restriction fragment length polymorphism. MIF levels were detected with enzyme-linked immunosorbent assay. Association analysis of polymorphism to TB showed that distribution of MIF −173 genotypes (GC+CC) was significantly higher in total cases of TB than in the controls. Statistically significant differences of frequencies for MIF −173 (GG vs. GC+CC) were demonstrated when comparing total cases of TB, new cases of TB, and retreatment cases of TB to controls, respectively. In contrast, the frequencies of MIF −173 (GG vs. GC+CC) demonstrated no difference between new cases of TB and retreatment cases of TB. Association analysis of MIF protein concentrations to TB indicated that MIF concentration is significantly higher in total cases of TB, new cases of TB, and retreatment cases of TB than in controls (P<0.01). In summary, our results demonstrated that MIF gene −173 G/C single nucleotide polymorphisms implicate in genetic susceptibility to TB, and GC+CC of MIF −173 site increases the risk of TB. We also found that no correlation between −173 G/C single nucleotide polymorphism and retreatment cases of TB in Yunnan Province population of China.

Abstract 16602: The Clinical Significance of Mif, Mif-2 and Mif Genotype in Patients Exhibited to Myocardial Ischemia/reperfusion Injury

Background: Cardiac surgery is increasingly been performed on an aging patient population with increased numbers of comorbid conditions. These patients are frequently exposed to myocardial ischemia/reperfusion with deleterious consequences and development of organ dysfunctions. The pleiotropic cytokine macrophage migration inhibitory factor (MIF) is an upstream regulator of the immune response and rapidly released from pre-formed cytoplasmatic pools in response to activating stimuli such as hypoxia, infection or inflammation. Yet, its interaction with related mediators such as its homolog, D-dopachrome tautomerase (MIF-2) is largely unknown. Therefore, we aimed to investigate the interaction and clinical significance of MIF and MIF-2 in patients undergoing cardiac surgery with myocardial ischemia/reperfusion. Methods and Results: Circulating levels of MIF and MIF-2 were measured peri-operatively in 100 patients that underwent elective cardiac surgery and showed a rapid increase upon myocardial ischemia. Intra-operative MIF levels reached maximum during myocardial reperfusion and were independently associated with a reduced risk for the development of AF in the post-operative period (odds ratio 0.99 (0.98-1.00); p=0.007), whereas circulating levels of MIF-2 were associated with an increased frequency of organ dysfunction and predicted the occurrence of atrial fibrillation (area under the curve (AUC)=0.663;p=0.041) and pneumonia (AUC=0.708;p=0.040). Known functional MIF allelic variants were analyzed and patients with high-expression MIF-genotype exhibited reduced incidence of organ dysfunction (3 vs. 25; p=0.042). Conclusion: Our findings present the first description of the kinetics and potential clinical relevance of the MIF, MIF-2 and MIF genotype in myocardial ischemia/reperfusion (I/R) in the setting of cardiac surgery. The present study demonstrated that increased intra-operative MIF levels may provide organoprotective effects, whereas elevated serum levels of MIF-2 were associated with the development of organ dysfunctions in patients after cardiac surgery. Patients with a high-expression MIF genotype experienced a significantly lower incidence of organ dysfunctions.

Proinflammatory Signature of the Dysfunctional Endothelium in Pulmonary Hypertension. Role of the Macrophage Migration Inhibitory Factor/CD74 Complex.

Inflammation and endothelial dysfunction are considered two primary instigators of pulmonary arterial hypertension (PAH). CD74 is a receptor for the proinflammatory cytokine macrophage migration inhibitory factor (MIF). This ligand/receptor complex initiates survival pathways and cell proliferation, and it triggers the synthesis and secretion of major proinflammatory factors and cell adhesion molecules. We hypothesized that the MIF/CD74 signaling pathway is overexpressed in idiopathic PAH (iPAH) and contributes to a proinflammatory endothelial cell (EC) phenotype. Primary early passage cultures of human ECs isolated from lung tissues obtained from patients with iPAH and controls were examined for their ability to secrete proinflammatory mediators and bind inflammatory cells with or without modulation of the functional activities of the MIF/CD74 complex. In addition, we tested the efficacies of curative treatments with either the MIF antagonist ISO-1 or anti-CD74 neutralizing antibodies on the aberrant proinflammatory EC phenotype in vitro and in vivo and on the progression of monocrotaline-induced pulmonary hypertension. In human lung tissues, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin expressions are markedly up-regulated in the endothelium of distal iPAH pulmonary arteries. Circulating MIF levels are increased in the serum of patients with PAH compared with control subjects, and T-cell lymphocytes represent a source of this overabundance. In addition, CD74 is highly expressed in the endothelium of muscularized pulmonary arterioles and in cultured pulmonary ECs from iPAH, contributing to an exaggerated recruitment of peripheral blood mononuclear cells to pulmonary iPAH ECs. Finally, we found that curative treatments with the MIF antagonist ISO-1 or anti-CD74 neutralizing antibodies partially reversed development of pulmonary hypertension in rats and substantially reduced inflammatory cell infiltration. We report here that CD74 and MIF are markedly increased and activated in patients with iPAH, contributing to the abnormal proinflammatory phenotype of pulmonary ECs in iPAH.

Role of Macrophage Migration Inhibitory Factor in Obesity, Insulin Resistance, Type 2 Diabetes, and Associated Hepatic Co-Morbidities: A Comprehensive Review of Human and Rodent Studies.

Obesity is associated with a chronic low-grade inflammatory state that drives the ­development of obesity-related co-morbidities such as insulin resistance/type 2 diabetes, non-alcoholic fatty liver disease (NAFLD), and cardiovascular disease. This metabolic inflammation is thought to originate in the adipose tissue, which becomes inflamed and insulin resistant when it is no longer able to expand in response to excess caloric and nutrient intake. The production of inflammatory mediators by dysfunctional adipose tissue is thought to drive the development of more complex forms of disease such as type 2 diabetes and NAFLD. An important factor that may contribute to metabolic inflammation is the cytokine macrophage migration inhibitory factor (MIF). Increasing evidence suggests that MIF is released by adipose tissue in obesity and that it is also involved in metabolic and inflammatory processes that underlie the development of obesity-related pathologies. This review provides a comprehensive summary of our current knowledge on the role of MIF in obesity, its production by adipose tissue, and its involvement in the development of insulin resistance, type 2 diabetes, and NAFLD. We discuss the main findings from recent clinical studies in obese subjects and weight-loss intervention studies as well as results from clinical studies in patients with insulin resistance and type 2 diabetes. Furthermore, we summarize findings from experimental disease models studying the contribution of MIF in obesity and insulin resistance, type 2 diabetes, and hepatic lipid accumulation and fibrosis. Although many of the findings support a pro-inflammatory role of MIF in disease development, recent reports also provide indications that MIF may exert protective effects under certain conditions.

Characterization of Chinese giant salamander iridovirus tissue tropism and inflammatory response after infection.

The Chinese giant salamander iridovirus (GSIV), belonging to the genus Ranavirus in the family Iridoviridae, causes severe hemorrhagic lesions and nearly 100% mortality in naturally infected Chinese giant salamanders Andrias davidiamus. However, the replication and distribution of the virus has not been well characterized in vivo. Using in situ hybridization, the expression of the GSIV major capsid protein (MCP) was detected in the cytoplasm of cells of the spleen, kidney, liver and gut tissues. MCP expression in the spleen and kidney appeared to fluctuate significantly during the acute phase of infection. Using an immunofluorescence assay, GSIV antigens were abundant in the spleen and kidney tissues but appeared to be at relatively low levels in the liver and gut. Additionally, there were significant changes in the expression of the pro-inflammatory cytokines macrophage migration inhibitory factor (MIF), tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β) in different tissues in response to infection with GSIV. The expression of MIF, TNF-α and IL-1β had significantly increased in the spleen at 3 d post-infection; this correlated with a decrease in virus replication in the spleen. These results suggest that the spleen and kidney are the major target tissues of GSIV, and the increased expression of MIF, TNF‑α and IL-1β may contribute to a reduction of virus replication in the spleen.