Role of macrophage migration inhibitory factor (MIF) in pollen-induced allergic conjunctivitis and pollen dermatitis in mice

Targeting macrophage migration inhibitory factor (MIF): a promising therapy for inflammatory ocular diseases

Inflammatory ocular diseases are characterized by the presence of a persistent inflammatory response which cause tissue injury, decrease visual acuity and in severe cases, blindness. Several cytokines represent a therapeutic opportunity since they are key amplifiers of these pathologies, and thus neutralizing agents against them have been developed. Amongst others, macrophage migration inhibitory factor (MIF), an early produced inflammatory cytokine, has consistently been found elevated in patients with distinct ocular diseases (inflammatory and autoimmune). Here, we present and discuss evidence showing that preclinical trials using diverse strategies to neutralize MIF resulted in significant attenuation of disease signs and therefore MIF blockage might be a promising therapy for ocular diseases.

Integrative Bioinformatics Analysis of mRNA Expression Profiles of Mice to Explore the Key Genes Involved in Crim1 Mutation-Induced Congenital Cataracts

Crim1 has been implicated in cataracts in mice and is of great importance in the development of the eye in both humans and mice. Therefore, we aimed to clarify how Crim1 mutations affect lens development and the molecular mechanism of cataracts in mice through comprehensive bioinformatics analysis. The microarray chip was downloaded from the GEO database to obtain the gene expression profile data set. Differentially expressed genes (DEGs) were screened using the limma package. GO and KEGG analyses of DEGs were performed using the DAVID database. Then, we established the protein-protein interaction (PPI) network in Cytoscape. Next, we used MCODE to analyze the data. We obtained 750 DEGs in total, including 407 upregulated DEGs and 343 downregulated DEGs. GO analysis showed that the DEGs were mainly related to biological processes, such as apoptosis, cell translation and the immune system. KEGG analysis showed that the enriched functions and pathways were related to the processing and presentation of ribosomes, lysosomes, and antigens. We identified 18 HUB genes, among which four core genes, C1qa, C1qb, C1qc, and Cd74, were closely related to congenital cataracts induced by Crim1 mutation. This study reveals the molecular pathogenesis of congenital cataracts induced by Crim1, and this information is expected to facilitate clinical genetic testing, molecular diagnosis, prognosis, and individualized chemotherapy for congenital cataracts (CC).

Haptenation of Macrophage Migration Inhibitory Factor: A Potential Biomarker for Contact Hypersensitivity

The immunological response in contact hypersensitivity is incited by small electrophilic compounds, known as haptens, that react with endogenous proteins after skin absorption. However, the identity of hapten-modified proteins seen as immunogenic remains as yet largely unknown. In a recent study, we have for the first time identified a hapten-modified protein in the local lymph nodes of mice treated topically with the model hapten tetramethylrhodamine isothiocyanate (TRITC). The TRITC modification was located on the N-terminal proline of the protein macrophage migration inhibitory factor (MIF). The focus of the current study was to investigate the presence of the same hapten-protein conjugate in blood samples from mice treated topically with TRITC. Furthermore, TRITC modifications of the two major blood proteins, namely hemoglobin (Hb) and albumin (Alb), as well as TRITC modifications of MIF other than the N-terminal proline, were examined. Following incubation with different molar ratios of TRITC, a proteomic approach was applied to characterize conjugate formation of the three aforementioned proteins, using high resolution mass spectrometry (HRMS). The targeted screening of the TRITC-treated mice blood and lymph node samples for these sites led to the identification of only the same TRITC-MIF conjugate previously detected in the lymph nodes. No Hb and Alb conjugates were detected. Quantification of both the TRITC-modified and unmodified N-terminal peptide of MIF in blood and lymph node samples gave interesting insights of MIF’s role in murine contact hypersensitivity. Incubation of MIF with four different haptens encompassing different reactivity mechanisms and potencies, showed adduct formation at different amino acid residues, suggesting that MIF can be the preferred target for a wide variety of haptens. The present study provides essential progress toward understanding of hapten-protein conjugate formation in contact hypersensitivity and identifies hapten-modified MIF as a potential biomarker for this condition. Further investigation of MIF as a target protein can be a next step to determine if MIF is a biomarker that can be used to develop better diagnostic tools and targeted therapeutics for individuals with allergic contact dermatitis.

The Role of MIF on Eosinophil Biology and Eosinophilic Inflammation

Macrophage migration inhibitory factor (MIF) is an inflammatory cytokine that participates in innate and adaptive immune responses. MIF contributes to the resistance against infection agents, but also to the cellular and tissue damage in infectious, autoimmune, and allergic diseases. In the past years, several studies demonstrated a critical role for MIF in the pathogenesis of type-2-mediated inflammation, including allergy and helminth infection. Atopic patients have increased MIF amounts in affected tissues, mainly produced by immune cells such as macrophages, Th2 cells, and eosinophils. Increased MIF mRNA and protein are found in activated Th2 cells, while eosinophils stock pre-formed MIF protein and secrete high amounts of MIF upon stimulation. In mouse models of allergic asthma, the lack of MIF causes an almost complete abrogation of the cardinal signs of the disease including mucus secretion, eosinophilic inflammation, and airway hyper-responsiveness. Additionally, blocking the expression of MIF in animal models leads to significant reduction of pathological signs of eosinophilic inflammation such as rhinitis, atopic dermatitis, eosinophilic esophagitis and helminth infection. A number of studies indicate that MIF is important in the effector phase of type-2 immune responses, while its contribution to Th2 differentiation and IgE production is not consensual. MIF has been found to intervene in different aspects of eosinophil physiology including differentiation, survival, activation, and migration. CD4+ T cells and eosinophils express CD74 and CXCR4, receptors able to signal upon MIF binding. Blockage of these receptors with neutralizing antibodies or small molecule antagonists also succeeds in reducing the signals of inflammation in experimental allergic models. Together, these studies demonstrate an important contribution of MIF on eosinophil biology and in the pathogenesis of allergic diseases and helminth infection.

The Effect of Long-Term Use of an Eyewash Solution on the Ocular Surface Mucin Layer

The use of eyewash solutions in Japan, especially in patients with allergic conjunctivitis and contact lens wearers, has been increasing. Our aim was to investigate how the use of preservative-free eyewash solution in healthy eyes for one month affects corneal safety and ocular surface mucin. We analyzed 42 eyes of 21 individuals (17 males, four females; mean age: 36.1 ± 7.4 years) without ocular allergies, dry eyes, or other ocular diseases through a prospective study. Eyes were randomized to a wash group (group one) and a nonwash follow up group (group two). We evaluated the dry eye-related quality-of-life score (DEQS), tear film breakup time (TBUT), fluorescein staining score, mRNA expression of MUC5AC and MUC16, MUC16 immunohistochemistry, and MUC5AC periodic acid Schiff (PAS) staining. There was a significant decrease in DEQS scores after one month of eyewash use (p < 0.05). There were no significant differences in other evaluation items that were analyzed (all p > 0.05). Furthermore, no significant differences were observed between group one and group two in all endpoints (all p > 0.05). The results suggest that one month use of a nonpreserved eyewash solution has no detrimental effects on the tear film and the ocular surface mucins.

Measurement of serum macrophage migration inhibitory factor (MIF) and correlation with severity and pruritus scores in client owned dogs with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a common inflammatory skin disease of dogs. Macrophage migration inhibitory factor (MIF) initiates pro-inflammatory cytokine release in human AD and serum concentrations are correlated with disease severity.

HYPOTHESIS

Canine serum MIF concentrations are increased in dogs with AD and correlate with clinical lesion and pruritus scores.

ANIMALS

Client owned dogs (n = 49) diagnosed with AD and 17 healthy, unaffected control dogs were used for the study.

METHODS AND MATERIALS

A commercially available MIF ELISA was optimized for the dog and serum from clinical cases used. Information regarding treatment, Canine Atopic Dermatitis Extent and Severity Index, (CADESI-4) and pruritus Visual Analog Scale (pVAS) were recorded for each dog at the time of serum collection.

RESULTS

Dogs with AD which had not received steroid therapy and those treated with oclacitinib had significantly elevated serum MIF concentrations compared to controls. Concentrations of MIF were not significantly different in AD dogs receiving steroids compared to controls. There was no significant correlation between MIF concentrations and clinical scores (CADESI-4 or pVAS).

CONCLUSIONS AND CLINICAL IMPORTANCE

Serum MIF concentrations are increased in dogs with AD and MIF might be a target for therapy.

Association of Macrophage Migration Inhibitory Factor Polymorphisms with Total Plasma IgE Levels in Patients with Atopic Dermatitis in Korea

The macrophage migration inhibitory factor (MIF) gene is located on human chromosome 22q11.2 and is linked to atopic phenotypes. Plasma MIF and log [total IgE] levels are significantly elevated in atopic dermatitis (AD) patients. The aim of this study was to evaluate the relationship between two MIF polymorphisms, −173 G to C and −794 CATT_5–8, and total plasma IgE levels in AD patients in Korea. We performed PCR-RFLP analysis in 178 AD patients and 80 control subjects to determine whether MIF SNPs are associated with susceptibility to AD. Plasma total IgE and MIF levels were determined, and then logistic regression analyses were performed to determine the associations between a SNP or haplotype and plasma total IgE or MIF levels. The −173 G/C polymorphism, located in the MIF promoter, was significantly associated with AD; the odds ratios (ORs) for the CC homozygotes and GC heterozygotes were 9.3 and 2.5, respectively. The MIF C/5-CATT and the MIF C/7-CATT haplotypes were significantly associated with AD; the ORs for the MIF C/5-CATT and MIF C/7-CATT haplotypes were 9.7 and 4.5, respectively. Log [total IgE] levels were highly associated with the MIF −794 7-CATT polymorphism. Notably, the MIF C/7-CATT haplotype was associated with a decrease in plasma log [total IgE] levels in a gene dose-dependent manner. Although log [MIF] levels were not associated with the MIF polymorphisms, the frequencies of the MIF C/5-CATT haplotype-containing genotypes decreased in order of MIF levels. Our results demonstrate that MIF promoter polymorphisms in the −173 C allele and the MIF C/5-CATT and C/7-CATT haplotypes were significantly associated with an increased risk for AD. In particular, the −794 7-CATT locus and the MIF C/7-CATT haplotype were significantly associated with decreased total IgE levels in the plasma, suggesting that these polymorphisms might be a marker for intrinsic AD rather than extrinsic AD that shows high total IgE levels and presence of allergen-specific IgE.