Role of macrophage migration inhibitory factor in influenza H5N1 virus pneumonia

The multifaceted roles of NLRP3-modulating proteins in virus infection

The innate immune response to viruses is critical for the correct establishment of protective adaptive immunity. Amongst the many pathways involved, the NLRP3 [nucleotide-binding oligomerisation domain (NOD)-like receptor protein 3 (NLRP3)] inflammasome has received considerable attention, particularly in the context of immunity and pathogenesis during infection with influenza A (IAV) and SARS-CoV-2, the causative agent of COVID-19. Activation of the NLRP3 inflammasome results in the secretion of the proinflammatory cytokines IL-1β and IL-18, commonly coupled with pyroptotic cell death. While this mechanism is protective and key to host defense, aberrant NLRP3 inflammasome activation causes a hyperinflammatory response and excessive release of cytokines, both locally and systemically. Here, we discuss key molecules in the NLRP3 pathway that have also been shown to have significant roles in innate and adaptive immunity to viruses, including DEAD box helicase X-linked (DDX3X), vimentin and macrophage migration inhibitory factor (MIF). We also discuss the clinical opportunities to suppress NLRP3-mediated inflammation and reduce disease severity.

Expression Patterns of Macrophage Migration Inhibitory Factor and Its Gene Variants (MIF-173 G˃C) in Verruca Vulgaris

Introduction

Verruca vulgaris is a benign hyperkeratotic proliferation of the epidermis. Few studies look at the differences in serum and tissue macrophage migration inhibitory factor (MIF) levels in verruca vulgaris, as well as its gene polymorphisms that have yet to be explored. The current study provided in-depth evaluation of MIF in serum and tissues of patients with verruca vulgaris, and establishes for the first time the possible association of MIF gene polymorphisms with common warts.

Methods

This case-control study included 50 patients who were diagnosed clinically as common warts in comparison with 50 age and sex-matched controls. Clinical examination was done on all included cases. Serum MIF was measured using enzyme-linked immunosorbent assay (ELISA), while its tissue expression was analyzed using Western blotting and immunohistochemical techniques for the included participants. Analysis of MIF-173 G˃C single nucleotide polymorphism was performed by polymerase chain reaction (PCR) using restriction fragment length polymorphism (RFLP) technique.

Results

The overall results revealed significantly lower MIF tissue expression in lesional and perilesional skin biopsies from cases compared to the controls using Western blot and immunohistochemical analysis. Yet, the difference in the serum MIF levels between cases and controls was not significant (p ˃ 0.05). GC genotype of the studied MIF rs755622 G>C SNP could be considered as a protective genetic factor against the occurrence of verruca vulgaris among Egyptians with OR (95% CI) equal 0.444 (0.199-0.989).

Conclusion

MIF and its genetic variants are thought to play a pathogenic role in verruca vulgaris development and recurrence.

Inhibition of Macrophage Migration Inhibitory Factor Activity Attenuates Haemorrhagic Shock-Induced Multiple Organ Dysfunction in Rats

Objective

The aim of this study was to investigate (a) macrophage migration inhibitory factor (MIF) levels in polytrauma patients and rats after haemorrhagic shock (HS), (b) the potential of the MIF inhibitor ISO-1 to reduce multiple organ dysfunction syndrome (MODS) in acute (short-term and long-term follow-up) HS rat models and (c) whether treatment with ISO-1 attenuates NF-κB and NLRP3 activation in HS.

Background

The MODS caused by an excessive systemic inflammatory response following trauma is associated with a high morbidity and mortality. MIF is a pleiotropic cytokine which can modulate the inflammatory response, however, its role in trauma is unknown.

Methods

The MIF levels in plasma of polytrauma patients and serum of rats with HS were measured by ELISA. Acute HS rat models were performed to determine the influence of ISO-1 on MODS. The activation of NF-κB and NLRP3 pathways were analysed by western blot in the kidney and liver.

Results

We demonstrated that (a) MIF levels are increased in polytrauma patients on arrival to the emergency room and in rats after HS, (b) HS caused organ injury and/or dysfunction and hypotension (post-resuscitation) in rats, while (c) treatment of HS-rats with ISO-1 attenuated the organ injury and dysfunction in acute HS models and (d) reduced the activation of NF-κB and NLRP3 pathways in the kidney and liver.

Conclusion

Our results point to a role of MIF in the pathophysiology of trauma-induced organ injury and dysfunction and indicate that MIF inhibitors may be used as a potential therapeutic approach for MODS after trauma and/or haemorrhage.

The Role of MIF and IL-10 as Molecular Yin-Yang in the Modulation of the Host Immune Microenvironment During Infections: African Trypanosome Infections as a Paradigm

African trypanosomes are extracellular flagellated unicellular protozoan parasites transmitted by tsetse flies and causing Sleeping Sickness disease in humans and Nagana disease in cattle and other livestock. These diseases are usually characterized by the development of a fatal chronic inflammatory disease if left untreated. During African trypanosome infection and many other infectious diseases, the immune response is mediating a see-saw balance between effective/protective immunity and excessive infection-induced inflammation that can cause collateral tissue damage. African trypanosomes are known to trigger a strong type I pro-inflammatory response, which contributes to peak parasitaemia control, but this can culminate into the development of immunopathologies, such as anaemia and liver injury, if not tightly controlled. In this context, the macrophage migration inhibitory factor (MIF) and the interleukin-10 (IL-10) cytokines may operate as a molecular “Yin-Yang” in the modulation of the host immune microenvironment during African trypanosome infection, and possibly other infectious diseases. MIF is a pleiotropic pro-inflammatory cytokine and critical upstream mediator of immune and inflammatory responses, associated with exaggerated inflammation and immunopathology. For example, it plays a crucial role in the pro-inflammatory response against African trypanosomes and other pathogens, thereby promoting the development of immunopathologies. On the other hand, IL-10 is an anti-inflammatory cytokine, acting as a master regulator of inflammation during both African trypanosomiasis and other diseases. IL-10 is crucial to counteract the strong MIF-induced pro-inflammatory response, leading to pathology control. Hence, novel strategies capable of blocking MIF and/or promoting IL-10 receptor signaling pathways, could potentially be used as therapy to counteract immunopathology development during African trypanosome infection, as well as during other infectious conditions. Together, this review aims at summarizing the current knowledge on the opposite immunopathological molecular “Yin-Yang” switch roles of MIF and IL-10 in the modulation of the host immune microenvironment during infection, and more particularly during African trypanosomiasis as a paradigm.

Macrophage migration inhibitory factor (MIF): A multifaceted cytokine regulated by genetic and physiological strategies

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine encoded within a functionally polymorphic genetic locus. MIF was initially recognized as a cytokine generated by activated T cells, but in recent days it has been identified as a multipotent key cytokine secreted by many other cell types involved in immune response and physiological processes. MIF is a highly conserved 12.5 kDa secretory protein that is involved in numerous biological processes. The expression and secretion profile of MIF suggests that MIF to be ubiquitously and constitutively expressed in almost all mammalian cells and is vital for numerous physiological processes. MIF is a critical upstream mediator of host innate and adaptive immunity and survival pathways resulting in the clearance of pathogens thus playing a protective role during infectious diseases. On the other hand, MIF being an immune modulator accelerates detrimental inflammation, promotes cancer metastasis and progression, thus worsening disease conditions. Several reports demonstrated that genetic and physiological factors, including MIF gene polymorphisms, posttranslational regulations, and receptor binding control the functional activities of MIF. Taking into consideration the multi-faceted role of MIF both in physiology and pathology, we thought it is timely to review and summarize the expressional and functional regulation of MIF, its functional mechanisms associated with its beneficial and pathological roles, and MIF-targeting therapies. Thus, our review will provide an overview on how MIF is regulated, its response, and the potency of the therapies that target MIF.

Expression of ssa-miR-155 during ISAV infection in vitro: Putative role as a modulator of the immune response in Salmo salar

Multiple cellular components are involved in pathogen-host interaction during viral infection; in this context, the role of miRNAs have become highly relevant. We assessed the expression of selected miRNAs during an in vitro infection of a Salmo salar cell line with Infectious Salmon Anemia Virus (ISAV), the causative agent of a severe disease by the same name. Salmon orthologs for miRNAs that regulate antiviral responses were measured using RT-qPCR in an in vitro time-course assay. We observed a modulation of specific miRNAs expression, where ssa-miR-155-5p was differentially over-expressed. Using in silico analysis, we identified the putative mRNA targets for ssa-miR-155-5p, finding a high prevalence of hosts immune response-related genes; moreover, several mRNAs involved in the viral infective process were also identified as targets for this miRNA. Our results suggest a relevant role for miR-155-5p in Salmo salar during an ISAV infection as a regulator of the immune response to the virus.

Evodiamine Enhanced the Anti-Inflammation Effect of Clindamycin in the BEAS-2B Cells Infected with H5N1 and Pneumoniae D39 Through CREB-C/EBPβ Signaling Pathway

Pneumonia is a pulmonary disease among children. Evodiamine, a traditional Chinese medicine, is known for anti-inflammatory effect. This study aimed to investigate the impact of evodiamine on severe pneumonia-like cells and the underlying mechanism involved. H5N1 and pneumoniae D39 was used to induce severe pneumonia-like conditions in BEAS-2B cells. The cell viability in BEAS-2B cells after treatments with 0, 20, 40, 60, 80, and 100 μM evodiamine was examined using MTT assays. The protein concentrations of inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, and Toll-like receptors (TLRs) were measured by enzyme-linked immunosorbent assay methods and the protein and mRNA changes in C/EBPβ/CREB were measured using Real Time-quantitative polymerase chain reaction and Western blot methods. Our results revealed that Evodiamine significantly decreased TNF-α, IL-6, and IL-1β in BEAS-2B cells. Moreover, evodiamine markedly reduced TLR2,3,4 protein expression and the phosphorylated protein of C/EBPβ and CREB. Besides, evodiamine combined with clindamycin exerted more significant effects than clindamycin alone. Taken together, our results demonstrated that evodiamine enhanced the anti-inflammation effect of clindamycin in the BEAS-2B cells infected with H5N1 and pneumoniae D39 through CREB-C/EBPβ signaling pathway.

2,2′-((1,4-Dimethoxy-1,4-dioxobutane-2,3-diylidene)bis(azanylylidene))bis(quinoline-3-carboxylic acid)

The title compound, 2,2′-((1,4-dimethoxy-1,4-dioxobutane-2,3-diylidene)bis(azanylylidene))bis(quinoline-3-carboxylic acid) was synthesized from isoxazolo[3,4-b]quinolin-3(1H)-one and dimethyl acetylenedicarboxylate (DMAD) via a double aza-Michael addition followed by [1,3]-H shifts. The product was characterized by infrared and nuclear magnetic resonance spectroscopy, as well as elemental analysis and high-resolution mass spectrometry (HRMS). The proposed reaction mechanism was rationalized by density functional theory (DFT) calculations.

Macrophage migration inhibitory factor (MIF) controls cytokine release during respiratory syncytial virus infection in macrophages

OBJECTIVE AND DESIGN

Respiratory syncytial virus (RSV) is the major cause of infection in children up to 2 years old and reinfection is very common among patients. Tissue damage in the lung caused by RSV leads to an immune response and infected cells activate multiple signaling pathways and massive production of inflammatory mediators like macrophage migration inhibitory factor (MIF), a pro-inflammatory cytokine. Therefore, we sought to investigate the role of MIF during RSV infection in macrophages.

METHODS

We evaluated MIF expression in BALB/c mice-derived macrophages stimulated with different concentrations of RSV by Western blot and real-time PCR. Additionally, different inhibitors of signaling pathways and ROS were used to evaluate their importance for MIF expression. Furthermore, we used a specific MIF inhibitor, ISO-1, to evaluate the role of MIF in viral clearance and in RSV-induced TNF-α, MCP-1 and IL-10 release from macrophages.

RESULTS

We showed that RSV induces MIF expression dependently of ROS, 5-LOX, COX and PI3K activation. Moreover, viral replication is necessary for RSV-triggered MIF expression. Differently, p38 MAPK in only partially needed for RSV-induced MIF expression. In addition, MIF is important for the release of TNF-α, MCP-1 and IL-10 triggered by RSV in macrophages.

CONCLUSIONS

In conclusion, we demonstrate that MIF is expressed during RSV infection and controls the release of pro-inflammatory cytokines from macrophages in an in vitro model.

A review on current trends in the treatment of human infection with H7N9-avian influenza A

The H7N9 subtype of avian influenza is an enzootic and airborne virus which caused an influenza outbreak in China. Infected individuals mostly worked with poultry, suggesting H7N9 virus-infected poultry as the primary source of human infection. Significantly increased levels of proinflammatory mediators (chemokines, cytokines) during virus infection could hamper the immune system and aggravate the infection. Severe cases are marked by fulminant pneumonia, acute respiratory distress syndrome (ARDS) and encephalopathy. Left untreated, the condition may rapidly progress to multi-organ failure and death. Reverse transcription polymerase chain reaction (rRT-PCR) is the gold standard diagnostic test for H7N9 avian influenza. Use of neurominidase inhibitor antivirals remain the main treatment. New antivirals are developed to counteract neurominidase inhibitor resistance H7N9 viral strains. Corticosteroid use in viral pneumonia may provoke mortality and longer viral shedding time. Subjects at high risk of contracting avian influenza H7N9 infection are recommended to receive annual seasonal influenza vaccination.

Macrophage migration inhibitory factor, a role in COPD

Macrophage migration inhibitor factor (MIF) is a pluripotent cytokine associated with several different inflammatory conditions, but its role within lung inflammation and chronic obstructive pulmonary disease (COPD) is unclear. This study aimed to examine MIF in both stable COPD and during acute exacerbations (AECOPD). The study included 433 patients with COPD aged 41-76 and 325 individuals from the Bergen COPD cohort study who served as controls. All patients had an FEV1 of <80% predicted, FEV1/FVC ratio of <0.7, and a smoking history >10 pack-years. Serum levels of MIF were compared between the two groups at baseline, and for 149 patients, measurements were also carried out during AECOPD. Linear regression models were fitted with MIF as the outcome variable and adjusted for sex, age, body composition, smoking, and Charlson Comorbidity Score (CCS). Median MIF (interquartile range) in patients with COPD was 20.1 ng/ml (13.5-30.9) compared with 14.9 ng/ml (11.1-21.6) in controls (P < 0.01). MIF was bivariately associated with sex, body composition, and CCS (P < 0.05 for all). In the regression analyses, MIF was significantly higher in patients with COPD, coefficient 1.32 (P < 0.01) and 1.30 (P < 0.01) unadjusted and adjusted, respectively. In addition, in 149 patients during episodes of AECOPD, MIF was significantly elevated, with a median of 23.2 ng/ml (14.1-42.3) compared with measurements at stable disease of 19.3 ng/ml (12.4-31.3, P < 0.01). Serum levels of MIF were significantly higher in patients with COPD compared with controls. We also identified an additional increase in MIF levels during episodes of AECOPD.

The role of C5a in acute lung injury induced by highly pathogenic viral infections

The complement system, an important part of innate immunity, plays a critical role in pathogen clearance. Unregulated complement activation is likely to play a crucial role in the pathogenesis of acute lung injury (ALI) induced by highly pathogenic virus including influenza A viruses H5N1, H7N9, and severe acute respiratory syndrome (SARS) coronavirus. In highly pathogenic virus-induced acute lung diseases, high levels of chemotactic and anaphylatoxic C5a were produced as a result of excessive complement activaiton. Overproduced C5a displays powerful biological activities in activation of phagocytic cells, generation of oxidants, and inflammatory sequelae named "cytokine storm", and so on. Blockade of C5a signaling have been implicated in the treatment of ALI induced by highly pathogenic virus. Herein, we review the literature that links C5a and ALI, and review our understanding of the mechanisms by which C5a affects ALI during highly pathogenic viral infection. In particular, we discuss the potential of the blockade of C5a signaling to treat ALI induced by highly pathogenic viruses.

Pathogenic roles of macrophage migration inhibitory factor during dengue virus infection

Dengue virus (DENV) infection is the most common cause of viral hemorrhagic fever, which can lead to life-threatening dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). Hemorrhage and plasma leakage are two major hallmarks of DHF/DSS. Because the mechanisms causing these pathogenic changes are unclear, there is no effective therapy against DHF/DSS. In this review, we focus on the possible pathogenic effects of a pleiotropic cytokine, macrophage migration inhibitory factor (MIF), on the pathogenesis of DENV infection. MIF is a critical mediator of the host immune response and inflammation, and there is a correlation between the serum levels of MIF and disease severity in dengue patients. Furthermore, MIF knock-out mice exhibit less severe clinical disease and lethality. However, the role of MIF in the pathogenesis of DHF/DSS is not limited to immune cell recruitment. Recent evidence indicates that DENV infection induced MIF production and may contribute to vascular hyperpermeability and viral replication during DENV infection. The expression of both adhesion and coagulation molecules on MIF-stimulated monocytes and endothelial cells is also increased, which may contribute to inflammatory and anticoagulatory states during DHF/DSS. Therefore, blocking MIF production or its function may provide a solution for the treatment and prevention of DHF/DSS.

Human single-chain variable fragment antibody inhibits macrophage migration inhibitory factor tautomerase activity

Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine, secreted from a variety of immune cells, that regulates innate and adaptive immune responses. Elevation of MIF levels in plasma correlates with the severity of inflammatory diseases in humans. Inhibition of MIF or its tautomerase activity ameliorates disease severity by reducing inflammatory responses. In this study, the human single-chain variable fragment (HuScFv) antibody specific to MIF was selected from the human antibody phage display library by using purified recombinant full-length human MIF (rMIF) as the target antigen. Monoclonal HuScFv was produced from phage-transformed bacteria and tested for their binding activities to rMIF by indirect enzyme-linked immunosorbent assay as well as to native MIF by western blot analysis and immunofluorescence assay. The HuScFv with highest binding signal to rMIF also inhibited the tautomerase activities of both rMIF and native MIF in human monoblastic leukemia (U937) cells in a dose-dependent manner. Mimotope searching and molecular docking concordantly demonstrated that the HuScFv interacted with Lys32 and Ile64 in the MIF tautomerase active site. To the best of our knowledge, this is the first study to focus on MIF-specific fully-human antibody fragment with a tautomerase-inhibitory effect that has potential to be developed as anti-inflammatory biomolecules for human use.

A Module Analysis Approach to Investigate Molecular Mechanism of TCM Formula: A Trial on Shu-feng-jie-du Formula

At the molecular level, it is acknowledged that a TCM formula is often a complex system, which challenges researchers to fully understand its underlying pharmacological action. However, module detection technique developed from complex network provides new insight into systematic investigation of the mode of action of a TCM formula from the molecule perspective. We here proposed a computational approach integrating the module detection technique into a 2-class heterogeneous network (2-HN) which models the complex pharmacological system of a TCM formula. This approach takes three steps: construction of a 2-HN, identification of primary pharmacological units, and pathway analysis. We employed this approach to study Shu-feng-jie-du (SHU) formula, which aimed at discovering its molecular mechanism in defending against influenza infection. Actually, four primary pharmacological units were identified from the 2-HN for SHU formula and further analysis revealed numbers of biological pathways modulated by the four pharmacological units. 24 out of 40 enriched pathways that were ranked in top 10 corresponding to each of the four pharmacological units were found to be involved in the process of influenza infection. Therefore, this approach is capable of uncovering the mode of action underlying a TCM formula via module analysis.

Macrophage migration inhibitory factor antagonist blocks the development of endometriosis in vivo

Endometriosis, a disease of reproductive age women, is a major cause of infertility, menstrual disorders and pelvic pain. Little is known about its etiopathology, but chronic pelvic inflammation is a common feature in affected women. Beside symptomatic treatment of endometriosis-associated pain, only two main suboptimal therapeutic approaches (hormonal and invasive surgery) are generally recommended to patients and no specific targeted treatment is available. Our studies led to the detection of a marked increase in the expression of macrophage migration inhibitory factor (MIF) in the eutopic endometrium, the peripheral blood and the peritoneal fluid of women with endometriosis, and in early, vascularized and active endometriotic lesions. Herein, we developed a treatment model of endometriosis, where human endometrial tissue was first allowed to implant into the peritoneal cavity of nude mice, to assess in vivo the effect of a specific antagonist of MIF (ISO-1) on the progression of endometriosis and evaluate its efficacy as a potential therapeutic tool. Administration of ISO-1 led to a significant decline of the number, size and in situ dissemination of endometriotic lesions. We further showed that ISO-1 may act by significantly inhibiting cell adhesion, tissue remodeling, angiogenesis and inflammation as well as by altering the balance of pro- and anti-apoptotic factors. Actually, mice treatment with ISO-1 significantly reduced the expression of cell adhesion receptors αv and ß3 integrins (P<0.05), matrix metalloproteinases (MMP) 2 and 9 (P<0.05), vascular endothelial cell growth factor (VEGF) (P<0.01), interleukin 8 (IL8) (P<0.05), cyclooxygenease (COX)2 (P<0.001) and the anti-apoptotic protein Bcl2 (P<0.01), but significantly induced the expression of Bax (P<0.05), a potent pro-apoptotic protein. These data provide evidence that specific inhibition of MIF alters endometriotic tissue growth and progression in vivo and may represent a promising potential therapeutic avenue.

MIF as a disease target: ISO-1 as a proof-of-concept therapeutic

Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine that has been implicated as playing a causative role in many disease states, including sepsis, pneumonia, diabetes, rheumatoid arthritis, inflammatory bowel disease, psoriasis and cancer. To inhibit the enzymatic and biologic activities of MIF, we and others have developed small-molecule MIF inhibitors. Most MIF inhibitors bind within the hydrophobic pocket that contains highly conserved amino acids known to be essential for MIF's proinflammatory activity. The best characterized of these small-molecule MIF inhibitors, (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) has been validated in scores of laboratories worldwide. Like neutralizing anti-MIF antibodies, ISO-1 significantly improves survival and reduces disease progression and/or severity in multiple murine models where MIF is implicated. This MIF inhibitor, its derivatives and other MIF-targeted compounds show great promise for future testing in disease states where increased MIF activity has been discovered.

Thyroxine is a potential endogenous antagonist of macrophage migration inhibitory factor (MIF) activity

Abnormally low plasma concentrations of thyroid hormones during sepsis often occur in the absence of thyroidal illness; however, the mechanisms involved in the "euthyroid sick syndrome" remain poorly understood. Here, we describe a previously unrecognized interaction between the thyroid hormone thyroxine (T(4)) and the proinflammatory cytokine macrophage migration inhibitory factor (MIF), together with its clinical relevance in sepsis. We found that in both patients with severe sepsis, and our rodent model, low plasma T(4) concentrations were inversely correlated with plasma MIF concentrations. The MIF molecule contains a hydrophobic pocket that is important for many of its proinflammatory activities. Binding of L-T(4) (or its hormonally inert isomer D-T(4)) significantly, and dose-dependently, inhibited the catalytic activity of this pocket. Moreover, administration of exogenous D-T(4) significantly improved survival in mice with severe sepsis. To examine the specificity of the MIFT(4) interaction, wild-type and MIF knockout mice were subjected to the carrageenan-air pouch model of inflammation and then treated with D-T(4) or vehicle. D-T(4) significantly inhibited leukocyte infiltration in wild-type mice but not in MIF knockout mice, providing evidence that in vivo T(4) may influence MIF-mediated inflammatory responses via inhibition of its hydrophobic proinflammatory pocket. These findings demonstrate a new physiological role for T(4) as a natural inhibitor of MIF proinflammatory activity. The data may also, in part, explain the low plasma T(4) concentrations in critically ill, euthyroid patients and suggest that targeting the imbalance between MIF and T(4) may be beneficial in improving outcome from sepsis.

The MIF -173G/C polymorphism and risk of childhood acute lymphoblastic leukemia in a Chinese population

Migration inhibitory factor (MIF) has recently been defined as a novel pro-tumorigenic factor that promotes cell proliferation, migration, and invasion. The MIF -173C allele results in increased MIF promoter activity and is associated with a higher serum MIF level. We hypothesized that this polymorphism may contribute to childhood acute lymphoblastic leukemia (ALL) susceptibility. We genotyped the MIF -173G/C polymorphism (rs755622) in 346 ALL cases and 516 cancer-free controls in a Chinese population and found that the variant genotype GC and the combined genotypes GC/CC were associated with a significantly higher risk of childhood ALL [adjusted odds ratio (OR)=1.39, 95% confidence interval (CI)=1.01-1.93 for GC and adjusted OR=1.38, 95% CI=1.01-1.89 for GC/CC]. In addition, we found that the increased risk was more pronounced among high-risk ALL and B-phenotype ALL patients. Our results suggest that the MIF -173G/C polymorphism is involved in the etiology of childhood ALL and is a potential candidate gene for determining cancer susceptibility. Further validations in other populations are warranted.

Inhibition of macrophage migration inhibitory factor ameliorates ocular Pseudomonas aeruginosa-induced keratitis

Pseudomonas aeruginosa causes severe sight-threatening corneal infections, with the inflammatory response to the pathogen being the major factor resulting in damage to the cornea that leads to loss of visual acuity. We found that mice deficient for macrophage migration inhibitory factor (MIF), a key regulator of inflammation, had significantly reduced consequences from acute P. aeruginosa keratitis. This improvement in the outcome was manifested as improved bacterial clearance, decreased neutrophil infiltration, and decreased inflammatory responses when P. aeruginosa-infected MIF knock out (KO) mice were compared to infected wild-type mice. Recombinant MIF applied to infected corneas restored the susceptibility of MIF deficient mice to P. aeruginosa-induced disease, demonstrating that MIF is necessary and sufficient to cause significant pathology at this immune privileged site. A MIF inhibitor administered during P. aeruginosa-induced infection ameliorated the disease-associated pathology. MIF regulated epithelial cell responses to infection by enhancing synthesis of proinflammatory mediators in response to P. aeruginosa infection and by promoting bacterial invasion of corneal epithelial cells, a correlate of virulence in the keratitis model. Our results uncover a host factor that elevates inflammation and propagates bacterial cellular invasion, and further suggest that inhibition of MIF during infection may have a beneficial therapeutic effect.