Macrophage migration inhibitory factor: critical role in obesity, insulin resistance, and associated comorbidities

Increased risk of atypical antipsychotics-induced metabolic syndrome associated with MIF CATT >5/6 among females with chronic schizophrenia

The utilization of atypical antipsychotics (AAPs) often leads to metabolic syndrome (MetS) in schizophrenia (SZ) patients. Macrophage migration inhibitory factor (MIF) is an important MetS-related cytokine. To investigate the potential association between the MIF-794 CATT5-8 polymorphism and AAP-induced MetS in SZ patients, data from 375 chronic SZ patients who received AAP treatment for a minimum of one year were included. MIF-794 CATT polymorphism genotyping and plasma MIF quantification was performed. The metabolism status of all patients was assessed according to the NCEP-ATP III criteria. Individuals who displayed at least three of the five risk factors (waist circumference, high-density lipoprotein cholesterol, triglycerides, fasting glucose levels, and blood pressure) were diagnosed with MetS. The prevalence of MetS in SZ patients with MIF CATT >5/6 was significantly higher than in those with CATT 5/5-5/6. In female patients, MIF CATT >5/6 was associated with an elevated risk of AAP-induced MetS after adjusting for covariates, particularly regarding abdominal obesity, and the mediating effect of plasma MIF levels was significant. In conclusion, MIF CATT >5/6 increased the risk of AAP-induced MetS among females with chronic SZ. The MIF-794 CATT5-8 microsatellite polymorphism may be a unique indicator for AAP-induced metabolic adverse effects in female SZ patients.

Involvement of the Macrophage Migration Inhibitory Factor (MIF) in Lipedema

Lipedema is a chronic disorder that mainly affects women. It is often misdiagnosed, and its etiology remains unknown. Recent research indicates an accumulation of macrophages and a shift in macrophage polarization in lipedema. One known protein superfamily that contributes to macrophage accumulation and polarization is the macrophage migration inhibitory factor (MIF) family. MIF-1 and MIF-2 are ubiquitously expressed and also regulate inflammatory processes in adipose tissue. In this study, the expression of MIF-1, MIF-2 and CD74-a common receptor for both cytokines-was analyzed in tissue samples of 11 lipedema and 11 BMI-matched, age-matched and anatomically matched control patients using qPCR and immunohistochemistry (IHC). The mRNA expression of MIF-1 (mean 1.256; SD 0.303; p = 0.0485) and CD74 (mean 1.514; SD 0.397; p = 0.0097) were significantly elevated in lipedema patients, while MIF-2 expression was unaffected (mean 1.004; SD 0.358; p = 0.9718). The IHC analysis corroborated the results for CD74 expression on a cellular level. In conclusion, our results provide first evidence for a potential involvement of the MIF family, presumably via the MIF-1-CD74 axis, in lipedema.

RNA-Sequencing Reveals Gene Expression and Pathway Signatures in Umbilical Cord Blood Affected by Birth Delivery Mode

Cesarean section (CS) confers increased risk of type I diabetes, asthma, inflammatory bowel disease, celiac disease, overweight and obesity, etc., in the offspring. However, the underlying mechanism remains unknown. To investigate the influence of CS on gene expression in cord blood, we have performed RNA-sequencing followed by single-gene analysis, gene set enrichment analysis, gene co-expression network analysis, and interacting genes/proteins analysis in eight full-term infants born by elective CS and eight matched vaginally delivered (VD) infants. Crucial genes identified above were further validated in another 20 CS and 20 VD infants. We found for the first time that mRNA expression of genes involved in immune response (IL12A, INFG, IL1B, TNF, MIF, IL4, CA1, IFI27, HLA-DOB and EPHB1) and metabolism (DLK1, CYP2A6 and GATM) were significantly influenced by CS. Notably, serum TNF-α and IFN-γ were remarkably up-regulated in the CS infants (p = 5.0 × 10-4 and 3.0 × 10-3, respectively) compared to the VD infants. It is biologically plausible that CS may exert adverse impacts on offspring health through influencing expression of genes in the above processes. These findings will help understand the potential underlying mechanisms of the adverse health impacts of CS and identify biomarkers for future health of offspring born with different delivery modes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43657-022-00086-7.

MIF rs755622 and IL6 rs1800795 Are Implied in Genetic Susceptibility to End-Stage Renal Disease (ESRD)

Chronic kidney disease (CKD) is characterized by an increased risk of kidney failure and end-stage renal disease (ESRD). Aging and comorbidities as cardiovascular diseases, metabolic disorders, infectious diseases, or tumors, might increase the risk of dialysis. In addition, genetic susceptibility factors might modulate kidney damage evolution. We have analyzed, in a group of ESRD patients and matched controls, a set of SNPs of genes (Klotho rs577912, rs564481, rs9536314; FGF23 rs7955866; IGF1 rs35767; TNFA rs1800629; IL6 rs1800795; MIF rs755622, rs1007888) chosen in relation to their possible involvement with renal disease and concomitant pathologies. Analysis of the raw data did indicate that IL6 rs180795 and MIF rs755622 SNPs might be markers of genetic susceptibility to ESRD. In particular, the C positive genotypes of MIF rs755622, (dominant model) seem to be an independent risk factor for ESDR patients (data adjusted for age, gender, and associated pathologies). Stratifying results according to age MIF rs755622 C positive genotype frequencies are increased in both the two age classes considered (<59 and ≥59-year-old subjects). Analyses of data according to gender allowed us to observe that ESRD women shoved a significantly reduced frequency of genotypes bearing IL6 rs180795 C allele. In addition, MIF rs755622 might interact with diabetes or hypercholesterolemia in increasing susceptibility to ESRD. In conclusion, our data indicate that some polymorphisms involved in the regulation of both renal function and inflammatory response can influence the evolution of chronic kidney disease and suggest that the modulation of the activities of these and other genes should also be considered as therapeutic targets on to intervene with innovative therapies.

The Role of MIF in Hepatic Function, Oxidative Stress, and Inflammation in Thioacetamide-induced Liver Injury in Mice: Protective Effects of Betaine

BACKGROUND

Macrophage migration inhibitory factor (MIF) is a multipotent cytokine that contributes to the inflammatory response to chemical liver injury. This cytokine exhibits pro- and anti-inflammatory effects depending on the etiology and stage of liver disease.

OBJECTIVE

Our study aimed to investigate the role of MIF in oxidative stress and inflammation in the liver, and modulatory effects of betaine on MIF in thioacetamide (TAA)-induced chronic hepatic damage in mice.

METHODS

The experiment was performed on wild type and knockout MIF-/- C57BL/6 mice. They were divided into the following groups: control; Bet-group that received betaine (2% wt/v dissolved in drinking water); MIF-/- mice group; MIF-/-+Bet; TAA-group that received TAA (200 mg/kg b.w.), intraperitoneally, 3x/week/8 weeks); TAA+Bet; MIF-/-+TAA, and MIF-/-+TAA+Bet. In TAA- and Bet-treated groups, animals received the same doses. After eight weeks of treatment, blood samples were collected for biochemical analysis, and liver specimens were prepared for the assessment of parameters of oxidative stress and inflammation.

RESULTS

In MIF-/-mice, TAA reduced transaminases, γ-glutamyltranspeptidase, bilirubin, malondialdehyde (MDA), oxidative protein products (AOPP), total oxidant status (TOS), C-reactive protein (CRP), IL-6, IFN-γ, and increased thiols and total antioxidant status (TAS). Betaine attenuated the mechanism of MIF and mediated effects in TAA-induced liver injury, reducing transaminases, γ-glutamyltranspeptidase, bilirubin, MDA, AOPP, TOS, CRP, IL-6, IFN-g, and increasing thiols.

CONCLUSION

MIF is a mediator in hepatotoxic, pro-oxidative, and proinflammatoryeffects of TAA-induced liver injury. MIF-targeted therapy can potentially mitigate oxidative stress and inflammation in the liver, but the exact mechanism of its action requires further investigation. Betaine increases anti-oxidative defense and attenuates hepatotoxic effects of MIF, suggesting that betaine can be used for the prevention and treatment of liver damage.

MIF -173G/C (rs755622) polymorphism modulates coronary artery disease risk: evidence from a systematic meta-analysis

BACKGROUND

Coronary artery disease (CAD) remains one of the major causes of death in humans. Genetic testing may allow early detection and prevention of this disease. This study aimed to investigate the association between the macrophage migration inhibitory factor (MIF) -173G/C (rs755622) polymorphism and susceptibility to CAD based on a meta-analysis.

METHODS

We searched several databases to identify observational case-control studies investigating the association between the MIF -173G > C (rs755622) polymorphism and CAD risk published before July 30, 2019. Data were analyzed using the STATA software.

RESULTS

Six studies, comprising a total of 1172 CAD cases and 1564 controls evaluated for MIF polymorphisms, were included. The occurrence of CAD was found to be associated with the C allele of the MIF rs755622 SNP in the total population (C/G, OR = 1.489, 95% CI = 1.223-1.813). Further, MIF -173G/C polymorphism was significantly associated with CAD under the allelic model in the Asian (C/G, OR = 1.775, 95% CI = 1.365-2.309) and Caucasian (C/G, OR = 1.288, 95% CI 1.003-1.654) subgroups. The data showed that the risk of CAD was higher in the population carrying the C allele.

CONCLUSIONS

We found evidence of associations between MIF -173C/G and CAD susceptibility in the Asian and Caucasian populations.

Macrophage migration inhibitory factor of Syrian golden hamster shares structural and functional similarity with human counterpart and promotes pancreatic cancer

Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine that increasingly is being studied in cancers and inflammatory diseases. Though murine models have been instrumental in understanding the functional role of MIF in different pathological conditions, the information obtained from these models is biased towards a specific species. In experimental science, results obtained from multiple clinically relevant animal models always provide convincing data that might recapitulate in humans. Syrian golden hamster (Mesocricetus auratus), is a clinically relevant animal model for multiple human diseases. Hence, the major objectives of this study were to characterize the structure and function of Mesocricetus auratus MIF (MaMIF) and finally evaluate its effect on pancreatic tumor growth in vivo. Initially, the recombinant MaMIF was cloned, expressed and purified in a bacterial expression system. The MaMIF primary sequence, biochemical properties, and crystal structure analysis showed greater similarity with human MIF. The crystal structure of MaMIF illustrates that it forms a homotrimer as known in human and mouse. However, MaMIF exhibits some minor structural variations when compared to human and mouse MIF. The in vitro functional studies show that MaMIF has tautomerase activity and enhances activation and migration of hamster peripheral blood mononuclear cells (PBMCs). Interestingly, injection of MaMIF into HapT1 pancreatic tumor-bearing hamsters significantly enhanced the tumor growth and tumor-associated angiogenesis. Together, the current study shows a structural and functional similarity between the hamster and human MIF. Moreover, it has demonstrated that a high level of circulating MIF originating from non-tumor cells might also promote pancreatic tumor growth in vivo.

Genetic Regulation of Enoyl-CoA Hydratase Domain-Containing 3 in Adipose Tissue Determines Insulin Sensitivity in African Americans and Europeans

Insulin resistance (IR) is a harbinger of type 2 diabetes (T2D) and partly determined by genetic factors. However, genetically regulated mechanisms of IR remain poorly understood. Using gene expression, genotype, and insulin sensitivity data from the African American Genetics of Metabolism and Expression (AAGMEx) cohort, we performed transcript-wide correlation and expression quantitative trait loci (eQTL) analyses to identify IR-correlated cis-regulated transcripts (cis-eGenes) in adipose tissue. These IR-correlated cis-eGenes were tested in the European ancestry individuals in the Metabolic Syndrome in Men (METSIM) cohort for trans-ethnic replication. Comparison of Matsuda index-correlated transcripts in AAGMEx with the METSIM study identified significant correlation of 3,849 transcripts, with concordant direction of effect for 97.5% of the transcripts. cis-eQTL for 587 Matsuda index-correlated genes were identified in both cohorts. Enoyl-CoA hydratase domain-containing 3 (ECHDC3) was the top-ranked Matsuda index-correlated cis-eGene. Expression levels of ECHDC3 were positively correlated with Matsuda index, and regulated by cis-eQTL, rs34844369 being the top cis-eSNP in AAGMEx. Silencing of ECHDC3 in adipocytes significantly reduced insulin-stimulated glucose uptake and Akt Ser⁴⁷³ phosphorylation. RNA sequencing analysis identified 691 differentially expressed genes in ECHDC3-knockdown adipocytes, which were enriched in γ-linolenate biosynthesis, and known IR genes. Thus, our studies elucidated genetic regulatory mechanisms of IR and identified genes and pathways in adipose tissue that are mechanistically involved in IR.

The Multitasking Potential of Alarmins and Atypical Chemokines

When the human genome was sequenced, it came as a surprise that it contains “only” 21,306 protein-coding genes. However, complexity and diversity are multiplied by alternative splicing, non-protein-coding transcripts, or post-translational modifications (PTMs) on proteome level. Here, we discuss how the multi-tasking potential of proteins can substantially enhance the complexity of the proteome further, while at the same time offering mechanisms for the fine-regulation of cell responses. Discoveries over the past two decades have led to the identification of “surprising” and previously unrecognized functionalities of long known cytokines, inflammatory mediators, and intracellular proteins that have established novel molecular networks in physiology, inflammation, and cardiovascular disease. In this mini-review, we focus on alarmins and atypical chemokines such as high-mobility group box protein-1 (HMGB-1) and macrophage migration-inhibitory factor (MIF)-type proteins that are prototypical examples of these classes, featuring a remarkable multitasking potential that allows for an elaborate fine-tuning of molecular networks in the extra- and intracellular space that may eventually give rise to novel “task”-based precision medicine intervention strategies.

MIF May Participate in Pathogenesis of Polycystic Ovary Syndrome in Rats through MAPK Signalling Pathway

The polycystic ovary syndrome (PCOS) model was established in rats and correlation between the expression of macrophage migration inhibitory factor (MIF) and cytokinesis with the MAPK signalling pathway in the rat ovary was measured. The PCOS model in rats was established by dehydroepiandrosterone (DHEA). Thirty sexually immature female Sprague-Dawley rats were randomly and equally assigned to three groups: control group, PCOS group, and PCOS with high-fat diet (HFD) group. Serum hormones were assayed by radioimmunoassay (RIA). The ovaries were immunohistochemically stained with MIF, and the expression of MIF, p-JNK and p-p38 was detected by Western blotting in ovaries. The serum testosterone level, LH concentration, LH/FSH ratio, fasting insulin level and HOMA IR index in the PCOS group (6.077±0.478, 13.809±1.701, 1.820±0.404, 10.83±1.123 and 1.8692±0.1096) and PCOS with HFD group (6.075±0.439, 14.075±1.927, 1.779±0.277, 10.20±1.377 and 1.7736±0.6851) were significantly higher than those in the control group (4.949±0.337, 2.458±0.509, 1.239±0.038, 9.53±0.548 and 1.5329±0.7363), but there was no significant difference between the PCOS group and PCOS with HFD group. The expression levels of MIF, p-JNK, and p-p38 in the PCOS group (0.4048±0.013, 0.6233±0.093 and 0.7987±0.061) and PCOS with HFD group (0.1929±0.012, 0.3346±0.103 and 0.3468±0.031) were obviously higher than those in control group (0.2492±0.013, 0.3271±0.093 and 0.3393±0.061), but no significant difference was observed between PCOS group and PCOS with HFD group. It was suggested that MIF may participate in the pathogenesis of PCOS through the MAPK signalling pathway in PCOS rats induced by DHEA.

Fenofibrate attenuates fatty acid-induced islet β-cell dysfunction and apoptosis via inhibiting the NF-κB/MIF dependent inflammatory pathway

BACKGROUND

Fatty acid-induced lipotoxicity and macrophage migration inhibitory factor (MIF) affect pancreatic β-cell function, and may promote the development of diabetes mellitus. However, the association of lipotoxicity with MIF and the effect of Fenofibrate on β-cell function remain unknown.

METHODS

LPL+/- mice and MIN6 cells stimulated with palmitic acid (PA) were utilized as models of lipid metabolism disorders. Factors associated with insulin secretion and apoptosis were assessed in the presence or absence of Fenofibrate. The possible mechanisms of lipotoxicity-induced β-cell dysfunction were also explored.

RESULTS

Fenofibrate effectively improved lipid accumulation in pancreatic β-cells, increased glucose-stimulated insulin secretion and β-cell mass, and significantly downregulated pro-apoptotic molecules, at the gene and protein levels, both in vivo and in vitro. Additionally, elevated MIF levels in serum from LPL+/- mice and PA-treated MIN6 cells were starkly decreased after Fenofibrate administration. Mechanistic analysis indicated that NF-κB signaling was remarkably triggered, which could further activate MIF transcription. Furthermore, Fenofibrate exerted beneficial effects on fatty acid-induced β-cell dysfunction likely by inhibiting the NF-κB/MIF dependent inflammatory response.

CONCLUSIONS

Fenofibrate ameliorates lipotoxicity-induced β-cell dysfunction and apoptosis by inhibiting the NF-κB/MIF inflammatory pathway. These findings provide novel insights into the treatment of lipotoxicity-induced metabolic disorders.

Disturbances of systemic and hippocampal insulin sensitivity in macrophage migration inhibitory factor (MIF) knockout male mice lead to behavioral changes associated with decreased PSA-NCAM levels

Macrophage migration inhibitory factor (MIF) is a multifunctional cytokine well known for its role in inflammation enhancement. However, a growing body of evidence is emerging on its role in energy metabolism in insulin sensitive tissues such as hippocampus, a brain region implicated in cognition, learning and memory. We hypothesized that genetic deletion of MIF may result in the specific behavioral changes, which may be linked tо impairments in brain or systemic insulin sensitivity by possible changes of the hippocampal synaptic plasticity. To assess memory, exploratory behavior and anxiety, three behavioral tests were applied on Mif gene-deficient (MIF^-/-) and "wild type" C57BL/6J mice (WT). The parameters of systemic and hippocampal insulin sensitivity were also determined. The impact of MIF deficiency on hippocampal plasticity was evaluated by analyzing the level of synaptosomal polysialylated-neural cell adhesion molecule (PSA-NCAM) plasticity marker and mRNA levels of different neurotrophic factors. The results showed that MIF^-/- mice exhibit emphasized anxiety-like behaviors, as well as impaired recognition memory, which may be hippocampus-dependent. This behavioral phenotype was associated with impaired systemic insulin sensitivity and attenuated hippocampal insulin sensitivity, characterized by increased inhibitory Ser³⁰⁷ phosphorylation of insulin receptor substrate 1 (IRS1). Finally, MIF^-/- mice displayed a decreased hippocampal PSA-NCAM level and unchanged Bdnf, NT-3, NT-4 and Igf-1 mRNA levels. The results suggest that the lack of MIF leads to disturbances of systemic and hippocampal insulin sensitivity, which are possibly responsible for memory deficits and anxiety, most likely through decreased PSA-NCAM-mediated neuroplasticity rather than through neurotrophic factors.

Association of genetic polymorphisms of macrophage inhibitory factor (MIF) and B-cell activating factor (BAFF) with the detection of donor specific antibodies in kidney allograft recipients

The posttransplant development of donor specific antibodies (DSA) initiates the antibody mediated rejection (AMR), which is associated with the increased rate of graft loss. One of the characteristics of AMR is the infiltration of innate immune system including macrophages, monocytes, neutrophils or NK cells. Macrophage inhibitory factor (MIF) and B-cell activating factor (BAFF) are well known cytokines that are associated with the activation of the innate immune system which can damage kidney allograft. In this article, the association of the genetic polymorphisms of MIF and BAFF with the development of DSA including Class I and II in kidney transplant patients is investigated. A total of 231 renal transplant patients between 2008 and 2012 at St. Vincent Medical Center, CA were studied in a retrospective study design. DSA were determined by Luminex technology, and single nucleotide polymorphisms (SNP) of MIF and BAFF were determined by the real time PCR based on 5' nuclease allelic discrimination assay. The genetic polymorphisms of MIF rs1007888 (C/T) was associated with increased risk of positive DSA detection (p=0.04) after transplantation, and consistently significant after 1year (p=0.016). Furthermore, the presence of C allele were associated with the increased risk of Class I DSA detection (OR 1.816, CI 1.141-2.889, p=0.011). Also, genetic polymorphisms of BAFF rs12583006 were associated with the increased risk of Class II DSA detection (p=0.033). In conclusion, the genetic polymorphisms of MIF and BAFF may increase the risk of posttransplant development of DSA. This result suggests the association between the development of posttransplant DSA and the activation of innate immune system.

Macrophage Migration Inhibitory Factor and Malondialdehyde as Potential Predictors of Vascular Risk Complications in Type 2 Diabetes Mellitus: Cross-Sectional Case Control Study in Saudi Arabia

Background. Malondialdehyde (MDA) has been implicated in the development of many acute inflammatory, autoimmune diseases as well as chronic inflammatory metabolic disorders. Involvement of inflammatory response and oxidative stress is currently suggested as a mechanism underlying development of diabetes and its complications. Objective. To evaluate the clinical utility of MDA, macrophage migration inhibitory factor (MIF), LDL-C/HDL-C, and TG/HDL-C ratio as noninvasive laboratory markers for prediction of T2DM vascular complications. Method. 63 Saudi T2DM patients and 16 age and sex matched controls were included. Serum MDA and MIF were assayed by thiobarbituric acid reactive substances and ELISA, respectively. TG/HDL-C and LDL-C/HDL-C ratios were calculated. Results. Uncontrolled DM patients had significantly higher levels of MDA, MIF, TG/HDL-C, and LDL-C/HDL-C ratios when compared with controlled DM patients and control group (p < 0.001). MDA had 100% sensitivity and 88% specificity. MIF showed 97% sensitivity and 100% specificity and LDL-C/HDL-C had 97% sensitivity and 95% specificity. Meanwhile, TG/HDL-C had the lowest sensitivity and specificity in identifying diabetic patients who would suffer from vascular complications. Conclusion. MDA, MIF, and LDL-C/HDL-C could be new predictors of metabolic disturbance which promote vascular complications in T2DM.

Altered Macrophage and Dendritic Cell Response in Mif-/- Mice Reveals a Role of Mif for Inflammatory-Th1 Response in Type 1 Diabetes

Macrophage migration inhibitory factor (Mif) is highly expressed in type 1 diabetes mellitus (T1DM). However, there is limited information about how Mif influences the activation of macrophages (Mφ) and dendritic cells (DC) in T1DM. To address this issue, we induced T1DM by administering multiple low doses of streptozotocin (STZ) to Mif-/- or wild-type (Wt) BALB/c mice. We found that Mif-/- mice treated with STZ (Mif-/-STZ) developed lower levels of hyperglycemia, inflammatory cytokines, and specific pancreatic islet antigen- (PIAg-) IgG and displayed reduced cellular infiltration into the pancreatic islets compared to Wt mice treated with STZ (WtSTZ). Moreover, Mφ and DC from Mif-/-STZ displayed lower expression of MHC-II, costimulatory molecules CD80, CD86, and CD40, Toll-like receptor- (TLR-) 2, and TLR-4 than WtSTZ. These changes were associated with a reduced capacity of Mφ and DC from Mif-/-STZ to induce proliferation in ovalbumin-specific T cells. All the deficiencies observed in Mif-/-STZ were recovered by exogenous administration of recombinant Mif. These findings suggest that Mif plays a role in the molecular mechanisms of Mφ and DC activation and drives T cell responses involved in the pathology of T1DM. Therefore, Mif is a potential therapeutic target to reduce the pathology of T1DM.

[Modifications of immunity in obesity: The impact on the risk of infection]

Incidence of obesity is constantly rising all over the world; obesity has developed into an important problem of public health. Clinical experience, supported by many clinical trials, shows that obesity constitutes a risk factor for numerous cardiovascular, metabolic, cancer and even infectious diseases. In this revue we summarize the present knowledge on immunological properties and functions of adipose tissue and their modifications in obese subjects, with a bending to a potentially deleterious chronic inflammatory state. We will discuss the negative impact of this chronic inflammation on physiological acute inflammatory reaction during infectious episodes. However, the modifications of anti-infectious immune response in obese subjects are not well known at present and need further investigations.

Central obesity, type 2 diabetes and insulin: exploring a pathway full of thorns

The prevalence of type 2 diabetes (T2D) is rapidly increasing. This is strongly related to the contemporary lifestyle changes that have resulted in increased rates of overweight individuals and obesity. Central (intra-abdominal) obesity is observed in the majority of patients with T2D. It is associated with insulin resistance, mainly at the level of skeletal muscle, adipose tissue and liver. The discovery of macrophage infiltration in the abdominal adipose tissue and the unbalanced production of adipocyte cytokines (adipokines) was an essential step towards novel research perspectives for a better understanding of the molecular mechanisms governing the development of insulin resistance. Furthermore, in an obese state, the increased cellular uptake of non-esterified fatty acids is exacerbated without any subsequent β-oxidation. This in turn contributes to the accumulation of intermediate lipid metabolites that cause defects in the insulin signaling pathway. This paper examines the possible cellular mechanisms that connect central obesity with defects in the insulin pathway. It discusses the discrepancies observed from studies organized in cell cultures, animal models and humans. Finally, it emphasizes the need for therapeutic strategies in order to achieve weight reduction in overweight and obese patients with T2D.

Macrophage migration inhibitory factor promoter polymorphisms (-794 CATT 5-8 and -173 G>C): relationship with mRNA expression and soluble MIF levels in young obese subjects

We analyzed the relationship of −794 CATT_5–8 and −173 G>C MIF polymorphisms with mRNA and soluble MIF in young obese subjects. A total of 250 young subjects, 150 normal-weight and 100 obese subjects, were recruited in the study. Genotyping of −794 CATT_5–8 and −173 G>C MIF polymorphisms was performed by PCR and PCR-RFLP, respectively. MIF mRNA expression was determined by real-time PCR and serum MIF levels were measured using an ELISA kit. For both MIF promoter polymorphisms, no significant differences in the genotype and allele frequencies between groups were observed. MIF mRNA expression was slightly higher in obese subjects than in normal-weight subjects (1.38-fold), while soluble MIF levels did not show differences between groups. In addition, we found an increase in MIF mRNA expression in carriers of the 6,6 and C/C genotypes and the 6G haplotype of the −794 CATT_5–8 and −173 G>C MIF polymorphisms, although it was not significant. In conclusion, this study found no relationship between obesity and MIF gene promoter polymorphisms with MIF mRNA expression in young obese subjects.

Mass Spectrometric Immunoassay for the qualitative and quantitative analysis of the cytokine Macrophage Migration Inhibitory Factor (MIF)

Background

The cytokine MIF (Macrophage Migration Inhibitory Factor) has diverse physiological roles and is present at elevated concentrations in numerous disease states. However, its molecular heterogeneity has not been previously investigated in biological samples. Mass Spectrometric Immunoassay (MSIA) may help elucidate MIF post-translational modifications existing in vivo and provide additional clarity regarding its relationship to diverse pathologies.

Results

In this work, we have developed and validated a fully quantitative MSIA assay for MIF, and used it in the discovery and quantification of different proteoforms of MIF in serum samples, including cysteinylated and glycated MIF. The MSIA assay had a linear range of 1.56-50 ng/mL, and exhibited good precision, linearity, and recovery characteristics. The new assay was applied to a small cohort of human serum samples, and benchmarked against an MIF ELISA assay.

Conclusions

The quantitative MIF MSIA assay provides a sensitive, precise and high throughput method to delineate and quantify MIF proteoforms in biological samples.

Macrophage migration inhibitory factor (MIF) knockout preserves cardiac homeostasis through alleviating Akt-mediated myocardial autophagy suppression in high-fat diet-induced obesity

Background

Macrophage migration inhibitory factor (MIF) plays a role in the development of obesity and diabetes. However, whether MIF plays a role in fat diet-induced obesity and associated cardiac anomalies still remains unknown. The aim of this study was to examine the impact of MIF knockout on high fat diet-induced obesity, obesity-associated cardiac anomalies and the underlying mechanisms involved with a focus on Akt-mediated autophagy.

Methods

Adult male wild-type (WT) and MIF knockout (MIF^−/−) mice were placed on 45% high fat diet for 5 months. Oxygen consumption, CO₂ production, respiratory exchange ratio (RER), locomotor activity, and heat generation were measured using energy calorimeter. Echocardiographic, cardiomyocyte mechanical and intracellular Ca²⁺ properties were assessed. Apoptosis was examined using TUNEL staining and western blot analysis. Akt signaling pathway and autophagy markers were evaluated. Cardiomyocytes isolated from WT and MIF^−/− mice were treated with recombinant mouse MIF (rmMIF).

Results

High fat diet feeding elicited increased body weight gain, insulin resistance, and caloric disturbance in WT and MIF^−/− mice. High fat diet induced unfavorable geometric, contractile and histological changes in the heart, the effects of which were alleviated by MIF knockout. In addition, fat diet-induced cardiac anomalies were associated with Akt activation and autophagy suppression, which were nullified by MIF deficiency. In cardiomyocytes from WT mice, autophagy was inhibited by exogenous rmMIF through Akt activation. In addition, MIF knockout rescued palmitic acid-induced suppression of cardiomyocyte autophagy, the effect of which was nullified by rmMIF.

Conclusions

These results indicate that MIF knockout preserved obesity-associated cardiac anomalies without affecting fat diet-induced obesity, probably through restoring myocardial autophagy in an Akt-dependent manner. Our findings provide new insights for the role of MIF in obesity and associated cardiac anomalies.

Association between the -794 (CATT)5-8 MIF gene polymorphism and susceptibility to acute coronary syndrome in a western Mexican population

The macrophage migration inhibitory factor (MIF) is related to the progression of atherosclerosis, which, in turn, is a key factor in the development of acute coronary syndrome (ACS). MIF has a CATT short tandem repeat (STR) at position -794 that might be involved in its expression rate. The aim of this study was to investigate the association between the -794 (CATT)5-8  MIF gene polymorphism and susceptibility to ACS in a western Mexican population. This research included 200 ACS patients classified according to the criteria of the American College of Cardiology (ACC) and 200 healthy subjects (HS). The -794 (CATT)5-8  MIF gene polymorphism was analyzed using a conventional polymerase chain reaction (PCR) technique. The 6 allele was the most frequent in both groups (ACS: 54% and HS: 57%). The most common genotypes in ACS patients and HS were 6/7 and 6/6, respectively, and a significant association was found between the 6/7 genotype and susceptibility to ACS (68% versus 47% in ACS and HS, resp., P = 0.03). We conclude that the 6/7 genotype of the MIF -794 (CATT)5-8 polymorphism is associated with susceptibility to ACS in a western Mexican population.

The critical role of macrophage migration inhibitory factor in insulin activity

Macrophage migration inhibitory factor (MIF) is a molecule with plethora of functions such as regulation of immune response, hormone-like, enzymatic and chaperone-like activity. Further, MIF is a major participant in glucose homeostasis since it is an autocrine stimulator of insulin secretion. MIF absence in male knockout mice (MIF-KO) results in development of glucose intolerance, while sensitivity to insulin is fully preserved. Since our results confirm that beta cells from MIF-KO mice express, produce and secrete insulin similarly to beta cells of their wild type (WT) counterparts C57BL/6 mice, we hypothesize that MIF-KO-derived insulin is less active. Indeed, insulin from MIF-KO islets is unable to significantly induce glucose uptake into hepatocytes and to efficiently promote insulin-triggered Akt phosphorylation determined by immunoblot. However, MIF's tautomerase function is not crucial for insulin biosynthesis since MIF inhibitors had no impact on WT insulin activity. Importantly, MIF recognition by anti-MIF antibody (ELISA) after in vitro co-incubation with purified insulin was significantly lower suggesting that insulin covers MIF immunodominant epitope. In addition, MIF binds insulin within beta cell as confirmed by co-immunoprecipitation. WT and MIF-KO-derived insulin exhibited different cleavage patterns suggesting different protein conformations. Finally, pre-incubation of recombinant MIF with insulin promotes formation of insulin hexamers. These results imply that MIF probably enables proper insulin folding what results in insulin full activity. This newly discovered feature of the cytokine MIF could be potentially important for commercially produced insulin, for increasing its stability and/or bioavailability.

The role of MIF in type 1 and type 2 diabetes mellitus

Autoimmunity and chronic low-grade inflammation are hallmarks of diabetes mellitus type one (T1DM) and type two (T2DM), respectively. Both processes are orchestrated by inflammatory cytokines, including the macrophage migration inhibitory factor (MIF). To date, MIF has been implicated in both types of diabetes; therefore, understanding the role of MIF could affect our understanding of the autoimmune or inflammatory responses that influence diabetic pathology. This review highlights our current knowledge about the involvement of MIF in both types of diabetes in the clinical environment and in experimental disease models.

Strength training and testosterone treatment have opposing effects on migration inhibitor factor levels in ageing men

Background. The beneficial effects of testosterone treatment (TT) are debated. Methods. Double-blinded, placebo-controlled study of six months TT (gel) in 54 men aged 60–78 with bioavailable testosterone (BioT) <7.3 nmol/L and waist >94 cm randomized to TT (50–100 mg/day, n = 20), placebo (n = 18), or strength training (ST) (n = 16) for 24 weeks. Moreover, the ST group was randomized to TT (n = 7) or placebo (n = 9) after 12 weeks. Outcomes. Chemokines (MIF, MCP-1, and MIP-1α) and lean body mass (LBM), total, central, extremity, visceral, and subcutaneous (SAT) fat mass established by DXA and MRI. Results. From 0 to 24 weeks, MIF and SAT decreased during ST + placebo versus placebo, whereas BioT and LBM were unchanged. TT decreased fat mass (total, central, extremity, and SAT) and increased BioT and LBM versus placebo. MIF levels increased during TT versus ST + placebo. ST + TT decreased fat mass (total, central, and extremity) and increased BioT and LBM versus placebo. From 12 to 24 weeks, MCP-1 levels increased during TT versus placebo and MCP-1 levels decreased during ST + placebo versus placebo. Conclusion. ST + placebo was associated with decreased MIF levels suggesting decreased inflammatory activity. TT may be associated with increased inflammatory activity. This trial is registered with ClinicalTrials.gov NCT00700024.

Nicotinamide-functionalized multiwalled carbon nanotubes increase insulin production in pancreatic beta cells via MIF pathway

Recent data in the literature support the role of nicotinamide (NA) as a pharmacologic agent that stimulates pancreatic beta-cells to produce insulin in vitro. There are data showing that carbon nanotubes may be useful in initiating and maintaining cellular metabolic responses. This study shows that administration of multiwalled carbon nanotubes (MWCNTs) functionalized with nicotinamide (NA-MWCNTs) leads to significant insulin production compared with individual administration of NA, MWCNTs, and a control solution. Treatment of 1.4E7 cells for 30 minutes with NA-MWCNTs at concentrations ranging from 1 mg/L to 20 mg/L resulted in significantly increased insulin release (0.18 ± 0.026 ng/mL for 1 mg/L, 0.21 ± 0.024 ng/mL for 5 mg/L, and 0.27 ± 0.028 ng/mL for 20 mg/L). Thus, compared with cells treated with NA only (0.1 ± 0.01 ng/mL for 1 mg/L, 0.12 ± 0.017 ng/mL for 5 mg/L, and 0.17 ± 0.01 ng/mL for 20 mg/L) we observed a significant positive effect on insulin release in cells treated with NA-MWCNTs. The results were confirmed using flow cytometry, epifluorescence microscopy combined with immunochemistry staining, and enzyme-linked immunosorbent assay techniques. In addition, using immunofluorescence microscopy techniques, we were able to demonstrate that MWCNTs enhance insulin production via the macrophage migration inhibitory factor pathway. The application and potential of NA combined with MWCNTs as an antidiabetic agent may represent the beginning of a new chapter in the nanomediated treatment of diabetes mellitus.

Macrophage migration inhibitory factor induces contractile and mitochondria dysfunction by altering cytoskeleton network in the human heart

OBJECTIVES

Macrophage migration inhibitory factor (MIF) has been recognized as a potent proinflammatory mediator that may induce myocardial dysfunction. Mechanisms by which MIF affects cardiac function are not completely elucidated; yet, some macrophage migration inhibitory effects have been related to changes in cytoskeleton architecture. We hypothesized that MIF-induced myocardial dysfunction and mitochondrial respiration deficit could be related to cardiac cell microtubule dynamics alterations.

DESIGN

Prospective, randomized study.

SETTING

Experimental Cardiovascular Laboratory, University Hospital.

SUBJECTS

Human myocardial (atrial) trabeculae.

INTERVENTIONS

Atrial trabeculae were obtained at the time of cardiac surgery. Isometrically contracting isolated human right atrial trabeculae were exposed to MIF (100 ng/mL) for 60 minutes, in the presence or not of pretreatment with colchicine (10 µM), a microtubule-depolymerizing agent, or paclitaxel (10 µM) a microtubule-stabilizing agent.

MEASUREMENTS AND MAIN RESULTS

Maximal active isometric tension curve and developed isometric force were studied. Trabeculae were then permeabilized for mitochondrial respiration studies using high-resolution oxygraphy. Heart fiber electron microscopy and visualization of βIV tubulin and polymerized actin by confocal microscopy were used to evaluate sarcomere and microtubule disarray. Compared with controls, MIF elicited cardiac contractile and mitochondrial dysfunction, which were largely prevented by pretreatment with colchicine, but not by paclitaxel. Pretreatment with colchicine prevented MIF-induced microtubule network disorganization, excessive tubulin polymerization, and mitochondrial fragmentation. Compound-C, an inhibitor of AMP-activated protein kinase (AMPK), partially prevented contractile dysfunction, suggesting that cardiac deleterious effects of MIF were related to AMPK activation.

CONCLUSIONS

MIF depresses human myocardial contractile function and impairs mitochondrial respiration. Changes in microtubule network likely promote MIF-induced cardiac dysfunction by 1) altering with mitochondrial tubular assembly and outer membrane permeability for adenine nucleotides leading to energy deficit, 2) excessive tubulin polymerization that may impede cardiomyocyte viscosity and motion, and 3) interfering with AMPK pathway.

Links between obesity, diabetes and ethnic disparities in breast cancer among Hispanic populations

Breast cancer is the most prevalent malignancy in women worldwide and is a growing concern due to rising incidence and ongoing ethnic disparities in both incidence and mortality. A number of factors likely contribute to these trends including rising rates of obesity and diabetes across the globe and differences in genetic predisposition. Here, we emphasize Hispanic populations and summarize what is currently known about obesity, diabetes and individual genetic predisposition as they relate to ethnic disparities in breast cancer incidence and mortality. In addition, we discuss potential contributions to breast cancer aetiology from molecular mechanisms associated with obesity and diabetes including dyslipidemia, hyperglycaemia, hyperinsulinaemia, endocrine dysfunction and inflammation. We propose that unique differences in diet and lifestyle coupled with individual genetic predisposition and endocrine/immune dysfunction explain most of the ethnic disparities seen in breast cancer incidence and mortality.

Inflammatory biomarkers for predicting cardiovascular disease

The pathology of cardiovascular disease (CVD) is complex; multiple biological pathways have been implicated, including, but not limited to, inflammation and oxidative stress. Biomarkers of inflammation and oxidative stress may serve to help identify patients at risk for CVD, to monitor the efficacy of treatments, and to develop new pharmacological tools. However, due to the complexities of CVD pathogenesis there is no single biomarker available to estimate absolute risk of future cardiovascular events. Furthermore, not all biomarkers are equal; the functions of many biomarkers overlap, some offer better prognostic information than others, and some are better suited to identify/predict the pathogenesis of particular cardiovascular events. The identification of the most appropriate set of biomarkers can provide a detailed picture of the specific nature of the cardiovascular event. The following review provides an overview of existing and emerging inflammatory biomarkers, pro-inflammatory cytokines, anti-inflammatory cytokines, chemokines, oxidative stress biomarkers, and antioxidant biomarkers. The functions of each biomarker are discussed, and prognostic data are provided where available.

Transcriptome analysis of epigenetically modulated genome indicates signature genes in manifestation of type 1 diabetes and its prevention in NOD mice

Classic genetic studies implicated several genes including immune response genes in the risk of developing type 1 diabetes in humans. However, recent evidence including discordant diabetes incidence among monozygotic twins suggested a role for epigenetics in disease manifestation. NOD mice spontaneously develop type 1 diabetes like humans and serve as an excellent model system to study the mechanisms of type 1 diabetes as well as the efficacy of maneuvers to manipulate the disease. Using this preclinical model, we have recently demonstrated that pharmacological inhibition of histone deacetylases can lead to histone hyperacetylation, selective up-regulation of interferon-γ and its transactivator Tbx21/Tbet, and amelioration of autoimmune diabetes. In the current study, we show that chromatin remodeling can render splenocytes incapable of transferring diabetes into immunodeficient NOD.scid mice. To elucidate the underlying mechanisms of drug-mediated protection against type 1 diabetes, we performed global gene expression profiling of splenocytes using high throughput microarray technology. This unbiased transcriptome analysis unraveled the exaggerated expression of a novel set of closely related inflammatory genes in splenocytes of acutely diabetic mice and their repression in mice cured of diabetes by chromatin remodeling. Analysis of gene expression by qRT-PCR using RNA derived from spleens and pancreata of cured mice validated the suppression of most of these genes, indicating an inverse correlation between the high levels of these inflammatory genes and protection against diabetes in NOD mice. In addition, higher-level expression of genes involved in insulin sensitivity, erythropoiesis, hemangioblast generation, and cellular redox control was evident in spleens of cured mice, indicating their possible contribution to protection against type 1 diabetes. Taken together, these results are consistent with the involvement of epistatic mechanisms in the manifestation of autoimmune diabetes and further indicate the utility of chromatin remodeling in curing this complex autoimmune disorder.

Tissue-specific regulation of inflammation by macrophage migration inhibitory factor and glucocorticoids in fructose-fed Wistar rats

High fructose consumption is commonly associated with insulin resistance, disturbed glucose homeostasis and low-grade inflammation. Increased glucocorticoid production within adipose tissue has been implicated in the pathogenesis of fructose-induced metabolic syndrome. Immunosuppressive actions of glucocorticoids can be counter-regulated by macrophage migration inhibitory factor (MIF), which is recognised as a key molecule in metabolic inflammation. In the present study, we hypothesised that coordinated action of glucocorticoids and MIF can mediate the effects of a high-fructose diet on adipose tissue and liver inflammation. We examined the effects of long-term consumption of a 10 % fructose solution on corticosterone (CORT) and MIF levels in rat blood plasma, liver and adipose tissue, as well as MIF and TNF-α mRNA expression and NF-κB activation in the same tissues. The high-fructose diet led to an increase in both CORT and MIF in the adipose tissue, and a highly significant positive correlation between their levels was observed. The attenuated NF-κB activation and unaltered TNF-α mRNA expression noticed in the adipose tissue could be interpreted as an outcome of the opposing actions of CORT and MIF. In contrast to adipose tissue, inflammation in the liver was characterised by NF-κB activation, an increased TNF-α mRNA level and unchanged levels of MIF protein, MIF mRNA and CORT. Overall, these findings suggest that a high-fructose diet differently affects the levels of glucocorticoids and MIF in the adipose tissue and liver, implicating that fructose over-consumption has tissue-specific effects on regulation of metabolic inflammation.

Macrophage migration inhibitory factor is elevated in obese adolescents

OBJECTIVES

The prevalence of obesity in childhood and adolescence is continuing rising. Macrophage migration inhibitory factor (MIF) participates in inflammatory and immune responses as a pro-inflammatory cytokine. The present study aimed to investigate MIF in overweight adolescents.

METHODS

Seventy-nine male adolescents were enrolled. Thirty-eight were overweight according to the 90th%ile of the age-specific waist circumference. Various parameters were recorded at one visit, including body mass index. MIF was determined using multiplex immune-assay technology.

RESULTS

Overweight adolescents had increased systolic blood pressure and CRP levels. Furthermore, increased circulating MIF concentrations were observed (Median: 964.6 pg/ml, Interquartile range: 590.3-2019.4 versus Median: 562.7 pg/ml, Interquartile range: 430.6-813.7, p = 0.003). Increased MIF concentrations were associated with increased markers of inflammation and obesity.

CONCLUSIONS

We demonstrated elevated MIF levels in obese adolescents. Taken together with other markers, this indicates the presence of low-grade inflammation in these young subjects, possibly representing a link between obesity and related co-morbidities.

Macrophage migration inhibitory factor gene polymorphisms and plasma levels in children with obstructive sleep apnea

INTRODUCTION

Obstructive sleep apnea (OSA) is associated with increased risk for cardiovascular and metabolic dysfunction in both adults and children. In adults with OSA, serum levels of macrophage migration inhibitory factor (MIF) are elevated. Therefore, we assessed plasma MIF levels and MIF allelic variant frequencies in children with and without OSA (NOSA).

METHODS

A total of 614 consecutive children ages 5-8 years were recruited. Children were divided into those with OSA and NOSA based on the apnea-hypopnea index (AHI). In addition to lipid profile, hsCRP, and fasting insulin and glucose levels, plasma MIF levels were assayed using ELISA, and 28 single nucleotide polymorphisms (SNPs) covering the region were genotyped. Linkage disequilibrium and haplotype blocks were analyzed using Haploview version 4.2 software.

RESULTS

Morning plasma MIF levels were increased in children with OSA. Of the 28 SNPs tested, the frequency of rs10433310 minor allele was significantly decreased in OSA. This SNP was also associated with reduced fasting insulin and hsCRP levels in OSA. The minor allele frequency of all other 27 SNPs was similar in OSA and NOSA groups.

CONCLUSIONS

Childhood OSA is associated with higher plasma MIF, hsCRP, and fasting insulin levels that promote cardiometabolic risk, and the MIF gene SNP rs10433310 may account for some of the variance in such risk.

Insulin resistance is increased in alopecia areata patients

Increased insulin resistance (IR) has been found in androgenetic alopecia in several studies. However, IR has not been investigated in alopecia areata (AA). We aimed to investigate IR in AA patients and the controls. Anthropometric and demographic data were obtained from 51 AA patients and 36 controls. We measured insulin, c-peptide and blood glucose and HOMA-IR. Demographic characteristics of the two groups were similar. AA group had higher insulin [12.5 ± 7.01 vs. 8.3 ± 3.9 µIU/mL, p = 0.001], c-peptide [2.7 ± 1.07 vs. 2. ± 0.6 ng/mL, p = 0.007] and HOMA-IR levels [2.8 ± 1.6 vs. 1.9 ± 0.9, p = .004] than the controls. Patient and control groups were also similar regarding lipid profiles. In this study, we found increased IR in AA patients for the first time in literature. Increased inflammatory cytokines and hypothalamic-pituitary-adrenal axis activation may be responsible for this finding. Further studies with larger sample sizes may give additional information for IR in AA.

Energy expenditure regulation via macrophage migration inhibitory factor in obesity and in vitro anti-macrophage migration inhibitory factor effect of Alpinia officinarum Hance extraction

OBJECTIVE

To compare the resting energy expenditure in different macrophage migration inhibitory factor (MIF) genotypes and to identify the in vitro effects of Alpinia officinarum Hance extract (AOHE) on MIF expression in obese and nonobese persons.

METHODS

In the fasting state, obese and nonobese persons were assessed for the measurement of resting energy expenditure rate (REE) by indirect calorimetry. We compared it with the expected amount ([REE measured by indirect calorimetry / predicted REE according to Harris Benedict equations] x 100). Participants were classified into those with normal REE (≥100) vs those with impaired REE (<100). Body composition was analyzed. Real-time polymerase chain reaction was performed using specific primer pairs for MIF messenger RNA, and β-actin was used as the internal control.

RESULTS

The study included 69 obese and 103 non-obese participants. The proportions of MIF genotypes were slightly different in obese and nonobese participants. However, the proportions of MIF genotypes were significantly different in participants with normal REE and those with low REE. The MIF gene was highly expressed in the obese group compared with MIF expression in the nonobese group. Body fat mass and MIF expression were higher in participants with the GG genotype than in the other genotype groups. MIF expression was inversely associated with REE in both groups (r = -0.36, P = .04). After treatment of peripheral blood mononuclear cells with AOHE, MIF expression differed according to MIF genotype.

CONCLUSIONS

Our results indicate that AOHE is a major modulator of MIF-dependent pathologic conditions in obesity and are consistent with mounting evidence that defines a regulating role for MIF in cytokine production in an inflammatory state in in vitro studies.

The action of D-dopachrome tautomerase as an adipokine in adipocyte lipid metabolism

Adipose tissue is a critical exchange center for complex energy transactions involving triacylglycerol storage and release. It also has an active endocrine role, releasing various adipose-derived cytokines (adipokines) that participate in complex pathways to maintain metabolic and vascular health. Here, we found D-dopachrome tautomerase (DDT) as an adipokine secreted from human adipocytes by a proteomic approach. DDT mRNA levels in human adipocytes were negatively correlated with obesity-related clinical parameters such as BMI, and visceral and subcutaneous fat areas. Experiments using SGBS cells, a human preadipocyte cell line, revealed that DDT mRNA levels were increased in an adipocyte differentiation-dependent manner and DDT was secreted from adipocytes. In DDT knockdown adipocytes differentiated from SGBS cells that were infected with the adenovirus expressing shRNA against the DDT gene, mRNA levels of genes involved in both lipolysis and lipogenesis were slightly but significantly increased. Furthermore, we investigated AMP-activated protein kinase (AMPK) signaling, which phosphorylates and inactivates enzymes involved in lipid metabolism, including hormone-sensitive lipase (HSL) and acetyl-CoA carboxylase (ACC), in DDT knockdown adipocytes. The AMPK phosphorylation of HSL Ser-565 and ACC Ser-79 was inhibited in DDT knockdown cells and recovered in the cells treated with recombinant DDT (rDDT), suggesting that down-regulated DDT in adipocytes brings about a state of active lipid metabolism. Furthermore, administration of rDDT in db/db mice improved glucose intolerance and decreased serum free fatty acids levels. In the adipose tissue from rDDT-treated db/db mice, not only increased levels of HSL phosphorylated by AMPK, but also decreased levels of HSL phosphorylated by protein kinase A (PKA), which phosphorylates HSL to promote its activity, were observed. These results suggested that DDT acts on adipocytes to regulate lipid metabolism through AMPK and/or PKA pathway(s) and improves glucose intolerance caused by obesity.

Macrophage migration inhibitory factor deficiency protects pancreatic islets from palmitic acid-induced apoptosis

As a result of chronic exposure to high levels of free fatty acids, glucose and inflammatory mediators β-cell apoptosis occurs at the end stage of obesity-associated type 2 diabetes (T2D). One potentially deleterious molecule for β-cell function associated with T2D and obesity in humans is macrophage migration inhibitory factor (MIF). Therefore, the aim of this study was to explore MIF expression in vivo during development of obesity and insulin resistance in high-fat diet (HFD)-fed C57BL/6 mice and whether MIF inhibition could affect β-cell apoptosis and dysfunction induced by palmitic acid (PA) in vitro. Indeed, increase in systemic and locally produced MIF correlated well with the weight gain, triglyceride upregulation, glucose intolerance and insulin resistance, which developed in HFD-fed mice. In in vitro settings PA dose-dependently induced MIF secretion before apoptosis development in islets. Further, mif gene deletion, mRNA silencing or protein inhibition rescued β-cells from PA-induced apoptosis as measured by MTT assay and histone-DNA enzyme linked immuno sorbent assay. Protection from induced apoptosis was mediated by altered activation of caspase pathway and correlated with changes in the level of Bcl-2 family members. Further, MIF inhibition conveyed a significant resistance to PA-induced downregulation of insulin and PDX-1 expression and ATP content. However, β-cell function was not entirely preserved in the absence of MIF judging by low glucose oxidation and depolarized mitochondrial membrane. In conclusion, the observed considerable preservation of β-cells from nutrient-induced apoptosis might implicate MIF as a potential therapeutic target in the later stage of obesity-associated T2D.

Tandem Repeats of the Catt Element of Macrophage Migration Inhibitory Factor Gene May Predict Gestational Diabetes Mellitus Severity

Previous investigations have demonstrated the association of the CATT repeated allele in the Macrophage migration inhibitory factor (MIF) with obesity and diabetes. Since there are common risk factors and molecular pathways in Type 2 Diabetes and Gestational Diabetes Mellitus (GDM), we focused on the associations of MIF variation with GDM. In a case-control study we enrolled 157 GDM and 217 healthy pregnant women, referred to the outpatient clinic of Shariati Hospital. The different repeats of CATT in MIF promoter were determined. MIF relative gene expression was evaluated in Peripheral blood mononuclear cells of all the participants. The GDM group had higher mean age and pre-gravid BMI. Also fasting serum glucose, insulin and MIF gene expression were significantly higher in the GDM patients. The statistically significant difference was observed between GDM and a healthy group in carrying 7-CATT allele and MIF gene expression. Regarding GDM risk factors, MIF 7-CATT allele showed significant relation with pre-pregnancy obesity, as well as the need for insulin therapy. Our results indicate that an association between MIF genotypes and its expression with GDM, obesity and the need of insulin for management of GDM patients exists.

A small-molecule inhibitor of macrophage migration inhibitory factor for the treatment of inflammatory disease

Multiple sclerosis (MS) is a chronic, debilitating disease of the central nervous system (CNS) characterized by demyelination and axon loss. The proinflammatory cytokine macrophage migration inhibitory factor (MIF) has been shown to be elevated in the cerebrospinal fluid of patients during relapses. The purpose of this study was to evaluate a new small-molecule inhibitor of MIF and its ability to reduce the severity of an animal model of MS, experimental autoimmune encephalomyelitis (EAE). We utilized 2 structurally related isoxazolines, which show in vitro inhibition of MIF tautomerase activity. We found that administration of an inhibitor of MIF to mice with established EAE immediately reduced the severity of clinical signs and expanded a population of regulatory T lymphocytes. We also noted that the inhibitor reduced relapses of disease in a relapsing/remitting model of EAE. An analysis of leukocyte migration into the brain revealed that administration of inhibitor reduced entry of these cells. No effects on inflammatory cytokine production or T-cell activation in the periphery were noted. From these studies, we conclude that a small-molecule inhibitor of MIF reduces the severity of EAE and prevents access of immune cells into the CNS, which could be of therapeutic relevance to MS.

Control of p53 and NF-κB signaling by WIP1 and MIF: role in cellular senescence and organismal aging

The stress-activated signaling pathways, p53 and NF-κB, have a major role in the regulation of cellular senescence and organismal aging. These ancient signaling networks display functional antagonism via negative autoregulatory circuits. WIP1 (wildtype p53-induced phosphatase 1) and MIF (macrophage migration inhibitory factor) are signaling molecules which link together the p53 and NF-κB pathways via positive and negative feedback loops. It seems that the efficiency of the p53 signaling pathway declines during aging whereas that of NF-κB is clearly enhanced. Moreover, p53 is an important trigger of cellular senescence while NF-κB signaling seems to be involved in the induction of the senescence-associated secretory phenotype (SASP). MIF is a pro-inflammatory cytokine which inhibits the function of p53 signaling whereas it is linked to NF-κB signaling via a positive feedback loop. MIF knockout mice are healthier and live longer than their wild-type counterparts. An increased level of MIF can support inflammatory responses via enhancing NF-κB signaling and repressing the function of p53. p53 is an inducer of the expression of WIP1 which can subsequently inhibit NF-κB signaling. Several observations indicate that the activity of WIP1 decreases during the aging process, this being probably attributable to the decline in p53 function. Decreased WIP1 activity potentiates the activity of p38MAPK and NF-κB signaling leading to premature cellular senescence as well as low-level chronic inflammation. We will review the findings linking WIP1 and MIF to specific signaling responses of p53 and NF-κB and discuss their role in the regulation of cellular senescence and organismal aging.