Brief report: Enhanced DRα1-mMOG-35-55 treatment of severe EAE in MIF-1-deficient male mice.

Macrophage migration inhibitory factor (MIF-1) and its homologue d-dopachrome tautomerase (MIF-2) share the common CD74 receptor and function innately to enhance severity of multiple sclerosis (MS) as well as the experimental autoimmune encephalomyelitis (EAE) model for MS. We previously demonstrated that genetically high-MIF-expressing male subjects with relapsing MS had a significantly greater risk of conversion to progressive MS (PMS) than lower-MIF-expressing males. To expand on this observation, we utilized MIF-1, MIF-2, and MIF-1/2-DUAL-deficient male mice to discern if there would be a greater contribution of these inflammatory factors in EAE mice with severe vs. moderate clinical disease signs. As shown previously, mice deficient in either MIF-1 or MIF-2 each had a ∼25% reduction of moderate EAE compared to WT mice, with significant differences in disease onset and trajectory. However, EAE induction in mice deficient in both MIF-1 and MIF-2 genes did not result in a further reduction in EAE severity. This result suggests that the two MIF homologues were likely affecting the same pathogenic pathways such that each could partially compensate for the other but not in an additive or synergistic manner. However, MIF-1-KO, MIF-2-KO, and MIF-1/2-DUAL-KO mice with severe EAE did not exhibit a significant reduction in cumulative EAE scores compared with WT mice, but the MIF-1-KO and, to a lesser extent, MIF-1/2-DUAL-KO mice did show a significant reduction in daily EAE scores over the last 3 days of observation, and MIF-2-KO mice showed a more modest but still consistent reduction over the same span. Furthermore, deletion of MIF-1 resulted in a massive reduction in the expression of EAE- and Complete Freund's Adjuvant-associated inflammatory factors, suggesting delayed involvement of the MIF/CD74 axis in promoting disease expression. To further explore modulation of MIF-1 and MIF-2 effects on EAE, we treated WT mice with moderate EAE using DRα1-mMOG-35-55, an inhibitor of CD74 that blocks both MIF-1 and MIF-2 action. This treatment reduced ongoing moderate EAE severity in excess of 25%, suggesting efficient blockade of the MIF/CD74 axis in disease-enhancing pathways. Moreover, DRα1-mMOG-35-55 treatment of mice with severe EAE strongly reversed EAE- and CFA-associated expression of inflammatory cytokines and chemokines including Tnf, Ccr7, Ccr6, Ccl8, Cxcr3, and Ccl19 in MIF-deficient mouse genotypes, and also exceeded innate MIF-1 and MIF-2 EAE enhancing effects, especially in MIF-1-KO mice. These results illustrate the therapeutic potential of targeting the disease-enhancing MIF/CD74 pathway in male mice with moderate and severe EAE, with implications for treatment of high-MIF-expressing RRMS human males at risk of conversion to progressive MS as well as those that have already transitioned to PMS.

Altered T cell subpopulations and serum anti-TYRP2 and tyrosinase antibodies in the acute and chronic phase of alopecia areata in the C3H/HeJ mouse model.

BACKGROUND: C3H/HeJ mouse models progress gradually in hair loss from acute to chronic phase and reflect the symptoms of patients with alopecia areata (AA). However, the underlying pathological characteristics alteration associated with disease progression and autoantigens remain unclear. OBJECTIVE: We aimed at elucidating the pathological differences between acute and chronic-AA in the C3H/HeJ mouse model. METHODS: We analyzed populations of PBMCs, skin-draining lymph node (SDLN) cells, and cutaneous cells of AA mice using flow cytometry. The cytokine and chemokine expressions in the serum and skin were determined using multiplex assay and qPCR. The antibody serum levels were determined using ELISA and the antigen-specific T cells were detected using the MHC class I tetramer. RESULTS: The CD8+NKG2D+ T and CD8+ TEM cell percentage in the chronic-AA SDLNs or among the unaffected and acute-AA mice PBMCs increased. The Th1 and CD4+ TEM cell percentage in the SDLNs and among PBMCs increased in the unaffected and AA mice. The percentage of CD8+ TEM/TRM cells and MHC class I expression increased in the lesions of acute-AA or the non-lesions and lesions of chronic-AA. The Th1 cells, dendritic cell-related cytokines, CD11c+ cells and MHC class II expression increased in the skin of AA mice. The antibody levels and TYRP2 and tyrosinase-specific CD8+ T cell percentages were upregulated in AA mice. CONCLUSION: These results suggest that the CD8+ and CD4+ T cell subpopulations, cytokine and chemokine expressions differ between the disease phases. Moreover, TYRP2 and tyrosinase are potential autoreactive targets in the AA mouse model.

Viral vector-mediated reprogramming of the fibroblastic tumor stroma sustains curative melanoma treatment.

The tumor microenvironment (TME) is a complex amalgam of tumor cells, immune cells, endothelial cells and fibroblastic stromal cells (FSC). Cancer-associated fibroblasts are generally seen as tumor-promoting entity. However, it is conceivable that particular FSC populations within the TME contribute to immune-mediated tumor control. Here, we show that intratumoral treatment of mice with a recombinant lymphocytic choriomeningitis virus-based vaccine vector expressing a melanocyte differentiation antigen resulted in T cell-dependent long-term control of melanomas. Using single-cell RNA-seq analysis, we demonstrate that viral vector-mediated transduction reprogrammed and activated a Cxcl13-expressing FSC subset that show a pronounced immunostimulatory signature and increased expression of the inflammatory cytokine IL-33. Ablation of Il33 gene expression in Cxcl13-Cre-positive FSCs reduces the functionality of intratumoral T cells and unleashes tumor growth. Thus, reprogramming of FSCs by a self-antigen-expressing viral vector in the TME is critical for curative melanoma treatment by locally sustaining the activity of tumor-specific T cells.

Role of MIF in coordinated expression of hepatic chemokines in patients with alcohol-associated hepatitis.

The chemokine system of ligands and receptors is implicated in the progression of alcohol-associated hepatitis (AH). Finding upstream regulators could lead to novel therapies. This study involved coordinated expression of chemokines in livers of healthy controls (HC) and patients with AH in 2 distinct cohorts of patients with various chronic liver diseases. Studies in cultured hepatocytes and in tissue-specific KO were used for mechanistic insight into a potential upstream regulator of chemokine expression in AH. Selected C-X-C chemokine members of the IL-8 chemokine family and C-C chemokine CCL20 were highly associated with AH compared with HC but not in patients with liver diseases of other etiologies (nonalcoholic fatty liver disease [NAFLD] and hepatitis C virus [HCV]). Our previous studies implicate macrophage migration inhibitory factor (MIF) as a pleiotropic cytokine/chemokine with the potential to coordinately regulate chemokine expression in AH. LPS-stimulated expression of multiple chemokines in cultured hepatocytes was dependent on MIF. Gao-binge ethanol feeding to mice induced a similar coordinated chemokine expression in livers of WT mice; this was prevented in hepatocyte-specific Mif-KO (MifΔHep) mice. This study demonstrates that patients with AH exhibit a specific, coordinately expressed chemokine signature and that hepatocyte-derived MIF might drive this inflammatory response.

CD8+ T cell self-tolerance permits responsiveness but limits tissue damage.

Self-specific CD8+T cells can escape clonal deletion, but the properties and capabilities of such cells in a physiological setting are unclear. We characterized polyclonal CD8+ T cells specific for the melanocyte antigen tyrosinase-related protein 2 (Trp2) in mice expressing or lacking this enzyme (due to deficiency in Dct, which encodes Trp2). Phenotypic and gene expression profiles of pre-immune Trp2/Kb-specific cells were similar; the size of this population was only slightly reduced in wild-type (WT) compared to Dct-deficient (Dct-/-) mice. Despite comparable initial responses to Trp2 immunization, WT Trp2/Kb-specific cells showed blunted expansion and less readily differentiated into a CD25+proliferative population. Functional self-tolerance clearly emerged when assessing immunopathology: adoptively transferred WT Trp2/Kb-specific cells mediated vitiligo much less efficiently. Hence, CD8+ T cell self-specificity is poorly predicted by precursor frequency, phenotype, or even initial responsiveness, while deficient activation-induced CD25 expression and other gene expression characteristics may help to identify functionally tolerant cells.

Associations between salivary cytokines and periodontal and microbiological parameters in orthodontic patients.

ABSTRACT: Orthodontic treatment can lead to microbial-induced gingival inflammation and aseptic periodontal inflammations. The aim of this study was to investigate the relationship between salivary pro-inflammatory cytokines levels with gingival health status and oral microbe loads among patients undergoing orthodontic treatment.The present investigation was a cross-sectional study among a sample of 111 consecutive orthodontic patients (mean age 18.4 ±â€Š4.4 years). Clinical examinations were conducted to assess the gingival health status employing the Modified Gingival Index, Gingival Bleeding Index, and Plaque Index. Salivary microbiological assessments of total aerobic and anaerobic bacteria count, streptococci count, and lactobacilli count were undertaken. Saliva immunological assessments included Interleukin-1Beta (IL-1ß) and macrophage migration inhibitory factor (MIF) ELISA assays.The mean ±â€Šstandard deviation of salivary IL-1ß was 83.52 ±â€Š85.62 pg/ml and MIF was 4.12 ±â€Š0.96 ng/ml. Moderate positive correlations were found between salivary IL-1ß levels and total aerobic and anaerobic bacteria count, streptococci count, and lactobacilli count (r = 0.380-0.446, P < .001), and weak positive correlations between salivary MIF levels and total salivary aerobic and anaerobic bacteria counts (r = 0.249-0.306, P < .01) were observed. A positive correlation was found between salivary IL-1ß levels and Bleeding Index (r = 0.216, P < .05).The level of salivary IL-1ß positively correlates with oral bacterial load among orthodontic patients; the relationship between inflammatory cytokines and oral microflora deserved further study.

Integrase-Defective Lentiviral Vector Is an Efficient Vaccine Platform for Cancer Immunotherapy.

Integrase-defective lentiviral vectors (IDLVs) have been used as a safe and efficient delivery system in several immunization protocols in murine and non-human primate preclinical models as well as in recent clinical trials. In this work, we validated in preclinical murine models our vaccine platform based on IDLVs as delivery system for cancer immunotherapy. To evaluate the anti-tumor activity of our vaccine strategy we generated IDLV delivering ovalbumin (OVA) as a non-self-model antigen and TRP2 as a self-tumor associated antigen (TAA) of melanoma. Results demonstrated the ability of IDLVs to eradicate and/or controlling tumor growth after a single immunization in preventive and therapeutic approaches, using lymphoma and melanoma expressing OVA. Importantly, LV-TRP2 but not IDLV-TRP2 was able to break tolerance efficiently and prevent tumor growth of B16F10 melanoma cells. In order to improve the IDLV efficacy, the human homologue of murine TRP2 was used, showing the ability to break tolerance and control the tumor growth. These results validate the use of IDLV for cancer therapy.

Macrophage migration inhibitory factor inhibits neutrophil apoptosis by inducing cytokine release from mononuclear cells.

The chemokine-like inflammatory cytokine macrophage migration inhibitory factor (MIF) is a pivotal driver of acute and chronic inflammatory conditions, cardiovascular disease, autoimmunity, and cancer. MIF modulates the early inflammatory response through various mechanisms, including regulation of neutrophil recruitment and fate, but the mechanisms and the role of the more recently described MIF homolog MIF-2 (D-dopachrome tautomerase; D-DT) are incompletely understood. Here, we show that both MIF and MIF-2/D-DT inhibit neutrophil apoptosis. This is not a direct effect, but involves the activation of mononuclear cells, which secrete CXCL8 and other prosurvival mediators to promote neutrophil survival. Individually, CXCL8 and MIF (or MIF-2) did not significantly inhibit neutrophil apoptosis, but in combination they elicited a synergistic response, promoting neutrophil survival even in the absence of mononuclear cells. The use of receptor-specific inhibitors provided evidence for a causal role of the noncognate MIF receptor CXCR2 expressed on both monocytes and neutrophils in MIF-mediated neutrophil survival. We suggest that the ability to inhibit neutrophil apoptosis contributes to the proinflammatory role ascribed to MIF, and propose that blocking the interaction between MIF and CXCR2 could be an important anti-inflammatory strategy in the early inflammatory response.

Skin immunization for effective treatment of multifocal melanoma refractory to PD1 blockade and Braf inhibitors.

BACKGROUND: Despite the remarkable benefits associated with the interventional treatment of melanomas (and other solid cancers) with immune checkpoint and Braf inhibitors (Brafi), most patients ultimately progress on therapy. The presence of multifocal/disseminated disease in patients increases their mortality risk. Hence, the development of novel strategies to effectively treat patients with melanomas that are resistant to anti-PD1 mAb (αPD1) and/or Brafi, particularly those with multifocal/disseminated disease remains a major unmet clinical need. METHODS: Mice developing induced/spontaneous BrafV600E/Pten-/- melanomas were treated by cutaneous immunization with a DNA vaccine encoding the melanoma-associated antigen TRP2, with Brafi or αPD1 alone, or with a combination of these treatments. Tumor progression, tumor-infiltration by CD4+ and CD8+ T cells, and the development of TRP2-specific CD8+ T cells were then monitored over time. RESULTS: Vaccination led to durable antitumor immunity against PD1/Brafi-resistant melanomas in both single lesion and multifocal disease models, and it sensitized PD1-resistant melanomas to salvage therapy with αPD1. The therapeutic efficacy of the vaccine was associated with host skin-resident cells, the induction of a systemic, broadly reactive IFNγ+CD8+ T cell repertoire, increased frequencies of CD8+ TIL and reduced levels of PD1hi/intCD8+ T cells. Extended survival was associated with improved TIL functionality, exemplified by the presence of enhanced levels of IFNγ+CD8+ TIL and IL2+CD4+ TIL. CONCLUSIONS: These data support the use of a novel genetic vaccine for the effective treatment of localized or multifocal melanoma refractory to conventional αPD1-based and/or Brafi-based (immune)therapy.

Macrophage migration inhibitory factor (MIF) and pregnancy may impact the balance of intestinal cytokines and the development of intestinal pathology caused by Toxoplasma gondii infection.

Toxoplasma gondii (T. gondii) is an intracellular parasite responsible for causing toxoplasmosis. When infection occurs during pregnancy, it can produce severe congenital infection with ocular and neurologic damage to the infant. From the oral infection parasite reaches the intestine, causing inflammatory response, damage in tissue architecture and systemic dissemination. Macrophage migration inhibition factor (MIF) is a cytokine secreted from both immune and non-immune cells, including gut epithelial cells. MIF is described to promote inflammatory responses, to be associated in colitis pathogenesis and also to play role in maintaining the intestinal barrier. The aim of the present study was to evaluate the influence of the pregnancy and MIF deficiency on T. gondii infection in the intestinal microenvironment and to address how these factors can impact on the intestinal architecture and local cytokine profile. For this purpose, small intestine of pregnant and non-pregnant C57BL/6 MIF deficient mice (MIF-/-) and Wild-type (WT) orally infected with 5 cysts of ME-49 strain of T. gondii were collected on day 8th of infection. Intestines were processed for morphological and morphometric analyses, parasite quantification and for cytokines mensuration. Our results showed that the absence of MIF and pregnancy caused an increase in T. gondii infection index. T. gondii immunolocalization demonstrated that segments preferentially infected with T. gondii were duodenum and ileum. The infection caused a reduction in the size of the intestinal villi, whereas, infection associated with pregnancy caused an increase in villi size due to edema caused by the infection. Also, the goblet cell number was increased in the ileum of MIF-/- mice, when compared to the corresponding WT group. Analyses of cytokine production in the small intestine showed that MIF was up regulated in the gut of pregnant WT mice due to infection. Also, infection provoked an intense Th1 response that was more exacerbated in pregnant MIF-/- mice. We also detected that the Th2/Treg response was more pronounced in MIF-/- mice. Altogether, our results demonstrated that pregnancy and MIF deficiency interferes in the balance of the intestinal cytokines and favors a Th1-immflamatory profile, which in turn, impact in the development of pathology caused by T. gondii infection in the intestinal microenvironment.

Inhibition of macrophage migration inhibitory factor prevents thyroid dysfunction in pregnant rats with acute pancreatitis.

Acute pancreatitis during pregnancy (APIP) rarely occurs but may lead to preterm delivery and be associated with high fetal mortality. Macrophage migration inhibitory factor (MIF) participates in various inflammatory diseases as a pro-inflammatory cytokine. In this study, we aimed to explore the effects of (S, R)-3-(4-hydroxyphenyl)-4, 5dihydro-5-isoxazole acetic methyl ester (ISO-1), an inhibitor of MIF, on maternal thyroid injury associated with APIP and its potential mechanisms in a pregnant rat model. APIP model was induced by retrograde injection of sodium taurocholate. ISO-1 was injected intraperitoneally 30 min before model establishment. The severity of pancreatitis was assessed by levels of tumor necrosis factor (TNF)­α, interleukin (IL)­1ß, IL-6 of maternal serum as well as histopathological score. Thyroid injury was determined by free triiodothyronine (FT3), free tetraiodothyronine (FT4) and thyroid histopathological score. Levels of MIF in maternal serum and the expression of MIF, CD68, CD3 and intercellular cell adhesion molecule-1 (ICAM-1) as well as oxidative stress status in maternal thyroid tissues were detected. Ultrastructure of maternal thyroid tissues was observed by transmission electron microscope. Thyroid injuries occurred in APIP and the lesions were attenuated with the pretreatment of ISO-1. Moreover, ISO-1 reduced the expression of MIF, attenuated the activations of CD68, CD3, ICAM-1 while improved oxidative stress status in maternal thyroid. Our research suggested a protective role of ISO-1 on thyroid injury and endocrine disorder during APIP, which may be associated with the inhibition of biological functions of MIF.

Lenalidomide and pomalidomide potently interfere with induction of myeloid-derived suppressor cells in multiple myeloma.

An increase in immunosuppressive myeloid-derived suppressor cells (MDSCs) is associated with disease progression and treatment resistance in multiple myeloma (MM). We investigated the mechanisms underlying MDSC induction, and sought to discover a strategy for prevention of MDSC induction in MM. Using a transwell co-culture system, four of nine examined human myeloma-derived cell lines (HMCLs) were potent in inducing monocytic (M)-MDSCs from normal peripheral blood mononuclear cells (PBMCs). As the results, we identified that secretion of C-C motif chemokine ligand 5 (CCL5) and macrophage migration inhibitory factor (MIF) by myeloma cells is a prerequisite for induction of MDSCs in MM. The immunomodulatory drug (IMiD) compounds, such as lenalidomide (LEN) and pomalidomide (POM), were identified as potent inhibitors of MDSC induction through bidirectional molecular effects of cereblon (CRBN)-dependent and -independent downregulation of CCL5 and MIF in myeloma cells; and downregulation of C-C motif chemokine receptor 5, a receptor for CCL5, and induction of interferon regulatory factor 8, a critical transcription factor for monocytic differentiation, in PBMCs. In the present study of the molecular mechanisms underlying MDSC induction, we identified a novel effect of LEN and POM of inhibiting MDSC induction via overlapping regulatory effects in myeloma cells and normal PBMCs.

Immune modulation by the macrophage migration inhibitory factor (MIF) family: D-dopachrome tautomerase (DDT) is not (always) a backup system.

Human macrophage migration inhibition factor (MIF) is a protein with cytokine and chemokine properties that regulates a diverse range of physiological functions related to innate immunity and inflammation. Most research has focused on the role of MIF in different inflammatory diseases. D-dopachrome tautomerase (DDT), a different molecule with structural similarities to MIF, which shares receptors and biological functions, has recently been reported, but little is known about its roles and mechanisms. In this review, we sought to understand the similarities and differences between these molecules by summarizing what is known about their different structures, receptors and mechanisms regulating their expression and biological activities with an emphasis on immunological aspects.

Functional tumor specific CD8 + T cells in spleen express a high level of PD-1.

The inhibitory effects of programmed cell death 1 (PD-1) receptor on tumor specific T cells were mainly investigated at tumor site. While PD-1 expression can be rapidly unregulated upon T cell activation at lymphoid tissues, little is known about where PD-1 signal exerts its inhibitory function in tumor-bearing host. To address this issue, we assessed the effects of PD-1 on vaccine induced activation of splenic CD8 + T cells in mice. The vaccine consisted of mice CD8 + T cell epitope peptide and poly IC. After vaccination, spleen or tumor tissues were dissociated, IFN-γ synthesis and PD-1 expression by CD8 + T cells were detected by flow cytometry. We found that CD8 + T cells could be successfully activated in spleen after immunization, characterized by the capability of producing IFN-γ when encountering relevant peptide. These activated splenic CD8 + T cells also expressed a high level of PD-1. Although PD-L1 expression in spleen parenchyma was also increased after vaccination, PD-1 blockade did not affect the activation of splenic CD8 + T cells, but enhanced the anti-tumor effects of peptide vaccine. This synergetic effect of peptide vaccine plus PD-1 blockade was coupled with increased aggregation of IFN-γ + CD8 + tumor infiltrated lymphocytes (TILs), rather than CD4 + TILs. The results indicated that for tumor-bearing host, PD-1 pathway exerted its inhibitory function at tumor site and PD-1 expression on the splenic CD8 + T cells correlated positively with IFN-γ synthesis.

The Role of Macrophage Migration Inhibitory Factor in Alzheimer's Disease: Conventionally Pathogenetic or Unconventionally Protective?

Recent preclinical and clinical observations have offered relevant insights on the etiopathogenesis of late onset Alzheimer's disease (AD) and upregulated immunoinflammatory events have been described as underlying mechanisms involved in the development of AD. Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine produced by several cells of the innate and adaptive immune system, as well as non-immune cells. In the present review, we highlight experimental, genetic, and clinical studies on MIF in rodent models of AD and AD patients, and we discuss emerging therapeutic opportunities for tailored modulation of the activity of MIF, that may potentially be applied to AD patients. Dismantling the exact role of MIF and its receptors in AD may offer novel diagnostic and therapeutic opportunities in AD.

Cross-kingdom mimicry of the receptor signaling and leukocyte recruitment activity of a human cytokine by its plant orthologs.

Human macrophage migration-inhibitory factor (MIF) is an evolutionarily-conserved protein that has both extracellular immune-modulating and intracellular cell-regulatory functions. MIF plays a role in various diseases, including inflammatory diseases, atherosclerosis, autoimmunity, and cancer. It serves as an inflammatory cytokine and chemokine, but also exhibits enzymatic activity. Secreted MIF binds to cell-surface immune receptors such as CD74 and CXCR4. Plants possess MIF orthologs but lack the associated receptors, suggesting functional diversification across kingdoms. Here, we characterized three MIF orthologs (termed MIF/d-dopachrome tautomerase-like proteins or MDLs) of the model plant Arabidopsis thaliana Recombinant Arabidopsis MDLs (AtMDLs) share similar secondary structure characteristics with human MIF, yet only have minimal residual tautomerase activity using either p-hydroxyphenylpyruvate or dopachrome methyl ester as substrate. Site-specific mutagenesis suggests that this is due to a distinct amino acid difference at the catalytic cavity-defining residue Asn-98. Surprisingly, AtMDLs bind to the human MIF receptors CD74 and CXCR4. Moreover, they activate CXCR4-dependent signaling in a receptor-specific yeast reporter system and in CXCR4-expressing human HEK293 transfectants. Notably, plant MDLs exert dose-dependent chemotactic activity toward human monocytes and T cells. A small molecule MIF inhibitor and an allosteric CXCR4 inhibitor counteract this function, revealing its specificity. Our results indicate cross-kingdom conservation of the receptor signaling and leukocyte recruitment capacities of human MIF by its plant orthologs. This may point toward a previously unrecognized interplay between plant proteins and the human innate immune system.

The emerging role of red blood cells in cytokine signalling and modulating immune cells.

For many years red blood cells have been described as inert bystanders rather than participants in intercellular signalling, immune function, and inflammatory processes. However, studies are now reporting that red blood cells from healthy individuals regulate immune cell activity and maturation, and red blood cells from disease cohorts are dysfunctional. These cells have now been shown to bind more than 50 cytokines and have been described as a sink for these molecules, and the loss of this activity has been correlated with disease progression. In this review, we summarise what is currently understood about the role of red blood cells in cytokine signalling and in modulating the activity of immune cells. We also discuss the implications of these findings for transfusion medicine and in furthering our understanding of anaemia of chronic inflammation. By bringing these disparate units of work together, we aim to shine a light on an area that requires significantly more investigation.

Transcriptomic Analysis Reveals Involvement of the Macrophage Migration Inhibitory Factor Gene Network in Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is a progressive hereditary muscular disease with X-linked recessive inheritance, that leads patients to premature death. The loss of dystrophin determines membrane instability, causing cell damage and inflammatory response. Macrophage migration inhibitory factor (MIF) is a cytokine that exerts pleiotropic properties and is implicated in the pathogenesis of a variety of diseases. Recently, converging data from independent studies have pointed to a possible role of MIF in dystrophic muscle disorders, including DMD. In the present study, we have investigated the modulation of MIF and MIF-related genes in degenerative muscle disorders, by making use of publicly available whole-genome expression datasets. We show here a significant enrichment of MIF and related genes in muscle samples from DMD patients, as well as from patients suffering from Becker's disease and limb-girdle muscular dystrophy type 2B. On the other hand, transcriptomic analysis of in vitro differentiated myotubes from healthy controls and DMD patients revealed no significant alteration in the expression levels of MIF-related genes. Finally, by analyzing DMD samples as a time series, we show that the modulation of the genes belonging to the MIF network is an early event in the DMD muscle and does not change with the increasing age of the patients, Overall, our analysis suggests that MIF may play a role in vivo during muscle degeneration, likely promoting inflammation and local microenvironment reaction.

Macrophage Migration Inhibitory Factor (MIF) Is Essential for Type 2 Effector Cell Immunity to an Intestinal Helminth Parasite.

Immunity to intestinal helminths is known to require both innate and adaptive components of the immune system activated along the Type 2 IL-4R/STAT6-dependent pathway. We have found that macrophage migration inhibitory factor (MIF) is essential for the development of effective immunity to the intestinal helminth Heligmosomoides polygyrus, even following vaccination which induces sterile immunity in wild-type mice. A chemical inhibitor of MIF, 4-IPP, was similarly found to compromise anti-parasite immunity. Cellular analyses found that the adaptive arm of the immune response, including IgG1 antibody responses and Th2-derived cytokines, was intact and that Foxp3+ T regulatory cell responses were unaltered in the absence of MIF. However, MIF was found to be an essential cytokine for innate cells, with ablated eosinophilia and ILC2 responses, and delayed recruitment and activation of macrophages to the M2 phenotype (expressing Arginase 1, Chil3, and RELM-α) upon infection of MIF-deficient mice; a macrophage deficit was also seen in wild-type BALB/c mice exposed to 4-IPP. Gene expression analysis of intestinal and lymph node tissues from MIF-deficient and -sufficient infected mice indicated significantly reduced levels of Arl2bp, encoding a factor involved in nuclear localization of STAT3. We further found that STAT3-deficient macrophages expressed less Arginase-1, and that mice lacking STAT3 in the myeloid compartment (LysMCrexSTAT3fl/fl) were unable to reject a secondary infection with H. polygyrus. We thus conclude that in the context of a Type 2 infection, MIF plays a critical role in polarizing macrophages into the protective alternatively-activated phenotype, and that STAT3 signaling may make a previously unrecognized contribution to immunity to helminths.

MiRNA Regulation of MIF in SLE and Attenuation of Murine Lupus Nephritis With miR-654.

Objective: Macrophage Migration Inhibitory Factor (MIF) is involved in the pathogenesis of systemic lupus erythematosus (SLE) and lupus nephritis (LN). MicroRNAs (miRNAs) play important roles in LN but whether specific miRNAs regulate the expression of MIF in LN is unknown. We explore specific miRNAs that can regulate MIF expression, and investigate miR-654 for the treatment of experimentally-induced murine lupus nephritis. Methods: Sera samples from 24 SLE patients and 24 controls were collected to measure the MIF concentration and its correlation with disease activity. A luciferase reporter assay was used to explore the target of miR-654. ELISA was used to detect the downstream cytokines regulated by miR-654 and MIF. Western blot was applied to measure the impact of miR-654 inhibition on downstream MIF signaling. The therapeutic efficacy of miR-654 was tested in the pristine-induced lupus mouse model. We further measured miR-654 expression and analyzed its relationship with MIF expression in SLE patients. Results: The serum MIF level was increased in SLE patients (p < 0.001) and positively correlated with the SLEDAI score (r = 0.5473; p = 0.0056). MiR-654 inhibited MIF and downstream inflammatory cytokine production by selectively inhibiting the phosphorylation of ERK and AKT. Activation of miR-654 reduced IL-1ß, IL-6, IL-8, and TNF-α production, reduced gomerulonephritis, and decreased MIF, IgG, and C3 expression in murine lupus glomeruli. Furthermore, MIF was negatively correlated with miR-654 expression (r = -0.4644; p = 0.0222) in SLE patients. Conclusion: MiR-654 negatively correlated with MIF and disease activity in patients with SLE. MiR-654 inhibits MIF expression via binding to MIF 3'UTR, selectively suppresses the phosphorylation of ERK and AKT, and reduces downstream inflammatory cytokine production. In vivo miR-654 treatment decreases MIF and downstream cytokine production and ameliorates murine lupus nephritis.