The roles of macrophage migration inhibitory factor in retinal diseases

Macrophage migration inhibitory factor(MIF),a multifunctional cytokine,is secreted by various cells and participates in inflammatory reactions,including innate and adaptive immunity.There are some evidences that MIF is involved in many vitreoretinal diseases.For example,MIF can exacerbate many types of uveitis;measurements of MIF levels can be used to monitor the effectiveness of uveitis treatment.MIF also alleviates trauma-induced and glaucoma-induced optic nerve damage.Furthermore,MIF is critical for retinal/choroidal neovascularization,especially complex neovascularization.MIF exacerbates retinal degeneration;thus,anti-MIF therapy may help to mitigate retinal degeneration.MIF protects uveal melanoma from attacks by natural killer cells.The mechanism underlying the effects of MIF in these diseases has been demonstrated:it binds to cluster of differentiation 74,inhibits the c-Jun N-terminal kinase pathway,and triggers mitogen-activated protein kinases,extracellular signal-regulated kinase-1/2,and the phosphoinositide-3-kinase/Akt pathway.MIF also upregulates Toll-like receptor 4 and activates the nuclear factor kappa-B signaling pathway.This review focuses on the structure and function of MIF and its receptors,including the effects of MIF on uveal inflammation,retinal degeneration,optic neuropathy,retinal/choroidal neovascularization,and uveal melanoma.

Brain-derived neurotrophic factor mediates macrophage migration inhibitory factor to protect neurons against oxygen-glucose deprivation

Macrophage migration inhibitory factor(MIF)is a chemokine that plays an essential role in immune system function.Previous studies suggested that MIF protects neurons in ischemic conditions.However,few studies are reported on the role of MIF in neurological recovery after ischemic stroke.The purpose of this study is to identify the molecular mechanism of neuroprotection mediated by MIF.Human neuroblastoma cells were incubated in Dulbecco’s modified Eagle’s medium under oxygen-glucose deprivation(OGD)for 4 hours and then returned to normal aerobic environment for reperfusion(OGD/R).30 ng/mL MIF recombinant(30 ng/mL)or ISO-1(MIF antagonist;50μM)was administered to human neuroblastoma cells.Then cell cultures were assigned to one of four groups:control,OGD/R,OGD/R with MIF,OGD/R with ISO-1.Cell viability was analyzed using WST-1 assay.Expression levels of brain-derived neurotrophic factor(BDNF),microtubule-associated protein 2(MAP2),Caspase-3,Bcl2,and Bax were detected by western blot assay and immunocytochemistry in each group to measure apoptotic activity.WST-1 assay results revealed that compared to the OGD/R group,cell survival rate was significantly higher in the OGD/R with MIF group and lower in the OGD/R with ISO-1 group.Western blot assay and immunocytochemistry results revealed that expression levels of BDNF,Bcl2,and MAP2 were significantly higher,and expression levels of Caspase-3 and Bax were significantly lower in the MIF group than in the OGD/R group.Expression levels of BDNF,Bcl2,and MAP2 were significantly lower,and expression levels of Caspase-3 and Bax were significantly higher in the ISO-1 group than in the OGD/R group.MIF administration promoted neuronal cell survival and induced high expression levels of BDNF,MAP2,and Bcl2(anti-apoptosis)and low expression levels of Caspase-3 and Bax(pro-apoptosis)in an OGD/R model.These results suggest that MIF administration is effective for inducing expression of BDNF and leads to neuroprotection of neuronal cells against hypoxic injury.

D-dopachrome tautomerase from Japanese sea bass(Lateolabrax japonicus) is a chemokine-like cytokine and functional homolog of macrophage migration inhibitory factor

D-dopachrome tautomerase(DDT),a member of the macrophage migration inhibitory factor(MIF)protein superfamily,is a newly described cytokine with chemokine-like characteristics.However,research on fish DDT remains limited.In this study,we identified a DDT homolog(LjDDT)from the Japanese sea bass,Lateolabrax japonicus.Sequence analysis showed that LjDDT had typical sequence features of known DDT and MIF homologs and was most closely related to DDT of rock bream(Oplegnathus fasciatus).LjDDT transcripts were detected in all tested tissues of healthy Japanese sea bass,with the highest expression found in the liver.Upon infection with Vibrio harveyi,LjDDT transcripts were significantly down-regulated in the three tested tissues,including the liver,spleen,and head kidney.Recombinant LjDDT(rLjDDT)and the corresponding antibody(anti-rLjDDT)were subsequently prepared.The administration of 100μg/g anti-rLjDDT had a statistically significant protective effect on the survival of V.harveyi-infected fish.Moreover,rLjDDT was able to induce the migration of monocytes/macrophages(MO/MФ)and lymphocytes both in vitro and in vivo,but without significant influence on the migration of neutrophils.rLjDDT exhibited chemotactic activity for lipopolysaccharide(LPS)-stimulated M1-type MO/MΦin vitro,but not for cAMP-stimulated M2-type MO/MΦ.Furthermore,the knockdown of LjCD74,but not LjCXCR4,significantly down-regulated the rLjDDT-enhanced migration of MO/MΦand relieved the rLjMIF-inhibited migration of MO/MΦ.These results indicate that LjCD74 may be the major chemotactic receptor of LjDDT and LjMIF in Japanese sea bass MO/MΦ.Combined rLjDDT+rLjMIF treatment had no significant effect on the migration of MsiRNA,LjCD74si-,or LjCXCR4sitreated MO/MΦcompared to the control group,suggesting that the roles of LjDDT and LjMIF may be antagonistic.In conclusion,our study demonstrates for the first time that DDT may play a role in the immune responses of fish against bacterial infection through chemotactic recruitment of MO/MΦvia mediation of CD74 as an antagonist of MIF.

Association of the macrophage migration inhibitory factor promoter polymorphisms with benign lymphoepithelial lesion of lacrimal gland

AIM:To identify the association of the macrophage migration inhibitory factor(MIF) gene polymorphism with the susceptibility of benign lymphoepithelial lesions(BLEL) of the lacrimal gland.METHODS:A total of 40 BLEL of lacrimal gland cases were matched with 40 healthy subjects(HS). Extraction the plasma and whole blood DNA of patients of lacrimal gland BLEL and HS. Elisa and polymerase chain reaction was used to determine in plasma contents of MIF and MIF gene SNP-173G>C and STR-794 CATT_(5-8) polymorphism,respectively.RESULTS: The MIF levels in plasma were significantly higher in patients with lacrimal gland BLEL versus HS(P<0.001). The-173 G>C MIF polymorphism was significantly associated with lacrimal gland BLEL,with a significantly higher frequency of the C allele in lacrimal gland BLEL patients compared with HS(OR=2.38,95% CI=1.07-5.31,P=0.032),and the-173 C/x is more frequent in patients than in HS,P=0.037.Besides,we found that the carriage rate of the MIF-173C/x is associated with higher plasma levels of MIF in the BLEL of lacrimal gland.CONCLUSION:MIF-173G/C variants play an insidious role in susceptibility of BLEL of lacrimal gland. Otherwise,there is no statistically significant correlation exists between MIF-794 CATT_(5-8) and BLEL of lacrimal gland.

Macrophage migration inhibitory factor decreased T-type Ca^(2+) channel current through activating Src

Aims T-type Ca2+ current(ICaT)plays an important role in the pathogenesis of atrial fibrillation（AF）.The present study sought to investigate the role of Macrophage migration inhibitory factor（MIF）,a pleiotropic cytokine,in the regulation of T-type Ca2+ channel in atrium myocytes.Methods We used whole-cell voltage-clamp technique and biochemical assays to study the regulation and expression of ICa,T in mouse atrium myocytes（HL-1 cells）.Results Serum MIF concentrations was slightly increased in patients with AF compared to sinus rhythm（SR） controls.In cultured HL-1 cells, significant amounts of MIF were produced in response to hydrogen peroxide（H2O2）,but not AngiotensinⅡ（AngⅡ）. Mouse recombinant MIF（rMIF）（20 or 40 nM,24 h） suppressed peak ICa,T by-38%and-60%in a concentration-dependent manner,impaired the voltage-dependent activation of ICa,T,and down-regulated of TCC alG mRNA.Src inhibitors genistein and PPl significantly enhanced ICaT.The depression of ICa,T induced by rMIF could be reversed by genistein and PP1.Conclusions MIFis involved in the pathogenesis of AF,probably by decreasing ICa,T through impairment of the channel function and activation of c-Src kinases in atrium myocytes.

Serum macrophage migration inhibitory factor as a potential biomarker to evaluate therapeutic response in patients with allergic asthma:an exploratory study

Background:Previous studies have shown that macrophage migration inhibitory factor(MIF)is involved in the pathogenesis of asthma.This study aimed to investigate whether serum MIF reflects a therapeutic response in allergic asthma.Methods:We enrolled 30 asthmatic patients with mild-to-moderate exacerbations and 20 healthy controls,analyzing the parameter levels of serum MIF,serum total immunoglobulin E(tIgE),peripheral blood eosinophil percentage(EOS%),and fractional exhaled nitric oxide(FeNO).Lung function indices were used to identify disease severity and therapeutic response.Results:Our study showed that all measured parameters in patients were at higher levels than those of controls.After one week of treatment,most parameter levels decreased significantly except for serum tIgE.Furthermore,we found that serum MIF positively correlated with EOS%as well as FeNO,but negatively correlated with lung function indices.Receiver operator characteristic(ROC)curve analysis indicated that among the parameters,serum MIF exhibited a higher capacity to evaluate therapeutic response.The area under the curve(AUC)of MIF was 0.931,with a sensitivity of 0.967 and a specificity of 0.800.Conclusions:Our results suggested that serum MIF may serve as a potential biomarker for evaluating therapeutic response in allergic asthma with mild-to-moderate exacerbations.

Macrophage migration inhibitory factor suppresses angiotensinⅡ-induced expression of fibrosis-associated genes by inactivating Smad3 and activating Nrf2 in cardiac fibroblasts

Background Macrophage migration inhibitory factor(MIF)is a key pro-inflammatory cytokine,exhibiting antioxidant properties. However,the role of MIF in cardiac fibrosis is not well known. In the present study,the effects of MIF on Smad3 and Nrf2 signalings in cardiac fibroblasts were investigated. Methods Cardiac fibroblasts were isolated from 1-3 days old C57 BL/6 mice,and the cardiac fibroblasts from passage 2 to 4 were used in this study. Expression of fibrosis-associated Col1 a1,Col3 a1 and α-SMA in mouse cardiac fibroblasts was detected by immunofluorescence staining and Western-blot assay,respectively. Intracellular oxidants in mouse cardiac fibroblasts were measured by using the probe dichlorofluoroscindiacetate(DCFH-DA)under confocal microscopy. Western-blot assay was also used to detect Smad3 and Nrf2,antioxidant proteins,MLL and HCF-1 in mouse cardiac fibroblasts. Results Immunofluorescence staining and Western-blot assay showed that MIF could markedly inhibit fibrosis-associated Col1 a1,Col3 a1 and α-SMA expression in cardiac fibroblasts. DCFHDA staining revealed that MIF can efficiently decrease reactive oxygen species(ROS)level in Ang-II-induced cardiac fibroblasts. Additionally,Smad3 activation was inhibited,but transcription factor Nrf2 and the downstream antioxidant genes,including HO-1,SOD-1,SOD2,Trx-2 and e-NOS,were increased in MIF-treated cardiac fibroblasts. MLL and HCF-1 were up-regulated by MIF,and either MLL knockdown or HCF-1 knockdown could consistently suppress Nrf2 expression in cardiac fibroblasts. Conclusions MIF possesses anti-fibrosis effect by inactivating Smad3 and activating Nrf2 in cardiac fibroblasts.

Integrative omics analysis identifies macrophage migration inhibitory factor signaling pathways underlying human hepatic fibrogenesis and fibrosis

The genetic basis underlying liver fibrosis remains largely unknown.We conducted a study to identify genetic alleles and underlying pathways associated with hepatic fibrogenesis and fibrosis at the genome-wide level in 121 human livers.By accepting a liberal significance level of P<1e-4,we identified 73 and 71 candidate loci respectively affecting the variability in alpha-smooth muscle actin(a-SMA)levels(fibrogenesis)and total collagen content(fibrosis).The top genetic loci associated with the two markers were BAZA1 and NOL10 for a-SMA expression and FAM46A for total collagen content(P<1e-6).We further investigated the relationship between the candidate loci and the nearby gene transcription levels(cis-expression quantitative trait loci)in the same liver samples.We found that 44 candidate loci for a-SMA expression and 44 for total collagen content were also associated with the transcription of the nearby genes(P<0.05).Pathway analyses of these genes indicated that macrophage migration inhibitory factor(MIF)related pathway is significantly associated with fibrogenesis and fibrosis,though different genes were enriched for each marker.The association between the single nucleotide polymorphisms,MIF and a-SMA showed that decreased MIF expression is correlated with increased a-SMA expression,suggesting that variations in MIF locus might affect the susceptibility of fibrogenesis through controlling MIF gene expression.In summary,our study identified candidate alleles and pathways underlying both fibrogenesis and fibrosis in human livers.Our bioinformatics analyses suggested MIF pathway as a strong candidate involved in liver fibrosis,thus further investigation for the role of the MIF pathway in liver fibrosis is warranted.The study was reviewed and approved by the Institutional Review Board(IRB)of Wayne State University(approval No.201842)on May 17,2018.

Macrophage migration inhibitory factor protects bone marrow mesenchymal stem cells from hypoxia/ischemia-induced apoptosis by regulating lncRNA

Objective:This research was performed to explore the effect of macrophage migration inhibitory factor(MIF)on the apoptosis of bone marrow mesenchymal stem cells(BMSCs)in ischemia and hypoxia environments.Methods:The cell viability of BMSCs incubated under hypoxia/ischemia(H/I)conditions with or without pretreatment with MIF or triglycidyl isocyanurate(TGIC)was detected using cell counting kit-8(CCK-8)analysis.Plasmids containing long noncoding RNA(lncRNA)maternally expressed gene 3(MEG3)orβ-catenin small interfering RNA(siRNA)were used to overexpress or downregulate the corresponding gene,and the p53 signaling pathway was activated by pretreatment with TGIC.The influences of MIF,overexpression of lncRNA MEG3,activation of the p53 signaling pathway,and silencing ofβ-catenin on H/I-induced apoptosis of BMSCs were revealed by western blotting,flow cytometry,and terminal deoxynucleotidyl transferase(TdT)-mediated dUTP nick-end labeling(TUNEL)staining.Results:From the results of CCK-8 assay,western blotting,and flow cytometry,pretreatment with MIF significantly decreased the H/I-induced apoptosis of BMSCs.This effect was inhibited when lncRNA MEG3 was overexpressed by plasmids containing MEG3.The p53 signaling pathway was activated by TGIC,andβ-catenin was silenced by siRNA.From western blot results,the expression levels ofβ-catenin in the nucleus and phosphorylated p53(p-p53)were downregulated and upregulated,respectively,when the lncRNA MEG3 was overexpressed.Through flow cytometry,MIF was also shown to significantly alleviate the increased reactive oxygen species(ROS)level of BMSCs caused by H/I.Conclusions:In summary,we conclude that MIF protected BMSCs from H/I-induced apoptosis by downregulating the lncRNA MEG3/p53 signaling pathway,activating the Wnt/β-catenin signaling pathway,and decreasing ROS levels.

Moxibustion of Zusanli(ST36)and Shenshu(BL23)alleviates the inflammation of rheumatoid arthritis in rats through regulating macrophage migration inhibitory factor/glucocorticoids signaling

OBJECTIVE:To test the hypothesis that moxibustion may inhibit rheumatoid arthritis(RA)synovial inflammation by regulating the expression of macrophage migration inhibitory factor(MIF)/glucocorticoids(GCs).METHODS:Fifty male Sprague-Dawley rats were randomly divided into five groups(n=10 each):blank Control(CON)group,RA Model(RA)group,Moxibustion(MOX)group,MIF inhibitor(S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester(ISO-1)group,and Moxibustion+MIF inhibitor ISO-1(MOX+ISO-1)group.Rats in the ISO-1 group and ISO-1+MOX group were intraperitoneally injected with the inhibitor ISO-1.The rats in the RA group,ISO-1 group,MOX group,and ISO-1+MOX group were injected with Freund's complete adjuvant(FCA)in the right hind footpad to establish an experimental RA rat model.In the MOX group and MOX+ISO-1 group,rats were treated with Moxa.The thickness of the footpads of the rats in each group was measured at three-time points before,after modeling and after moxibustion treatment.The contents of serum MIF,corticosterone(CORT),tumor necrosis factor-α(TNF-α)and interleukin-1β(IL-1β)were detected by enzyme-linked immunosorbent assay;and the contents of synovial MIF were detected by Western blot.Hematoxylin-eosin(HE)staining method was used to observe the pathological changes of synovial tissue under a section light microscope,and pathological scoring was performed according to the grading standard of the degree of synovial tissue disease.RESULTS:Moxibustion was found to reduce the level of MIF and alleviate inflammation in RA rats in this study.In addition,after inhibiting the expression of MIF,the level of CORT increased,and the level of TNF-α decreased.Treating RA rats with inhibited MIF by moxibustion,the level of CORT was almost unchanged,but the level of TNF-α further decreased.The correlation analysis data suggested that MIF was positively related to the expression of TNF-α and negatively correlated with the expression of CORT.CONCLUSION:Reducing MIF to increase CORT and decrease TNF-α by moxibustion treatment in RA.MIF may be a factor for moxibustion to regulate the expression of CORT,but the expression of TNF-α is due to the incomplete regulation of the MIF.This study added to the body of evidence pointing to moxibustion's antiinflammatory mechanism in the treatment of RA.

Inflammatory cytokine gene polymorphisms increase the risk of atrophic gastritis and intestinal metaplasia

AIM: To investigate the effects of interleukin-8 (IL-8 ), macrophage migration inhibitory factor (MIF ) gene polymorphisms, Helicobacter pylori (H. pylori ) infection, on the risk of developing severe chronic atrophic gastritis (SCAG) and intestinal metaplasia (IM). METHODS: A total of 372 cases were selected from a cohort study in Linqu County, a high risk area for gastric cancer (GC) in northern China. To obtain a sufficient group size, patients with normal or superficial gastritis were included. Based on an average follow-up period of 56 mo, the 372 cases were divided into no progres-sion group (no histological progression from normal or superficial gastritis, n = 137), group Ⅰ (progressed from normal or superficial gastritis to SCAG, n = 134) and group Ⅱ (progressed from normal or superficial gastritis to IM, n = 101). IL-8 , MIF gene polymorphisms were detected by polymerase chain reaction-based denaturing high-performance liquid chromatography analysis and DNA sequencing. RESULTS: An increased risk of SCAG was found in subjects with IL-8-251 AA genotype [odds ratio (OR) = 2.62, 95% CI: 1.23-5.72] or IL-8-251 A allele carriers (AA + AT) (OR = 1.81, 95% CI: 1.06-3.09). An elevated risk of IM was found in subjects with IL-8-251 AT genotype (OR = 2.27, 95% CI: 1.25-4.14) or IL-8-251 A allele carriers (OR = 2.07, 95% CI: 1.16-3.69). An increased risk of SCAG was found in subjects with MIF-173 GC genotype (OR = 2.36, 95% CI: 1.38-4.02) or MIF-173 C allele carriers (GC + CC) (OR = 2.07, 95% CI: 1.21-3.55). An elevated risk of IM was found in subjects with MIF-173 CC genotype (OR = 2.27, 95% CI: 1.16-4.46) or MIF-173 C allele carriers (OR = 3.84, 95% CI: 1.58-9.34). The risk of SCAG and IM was more evident in subjects carrying IL-8-251 A allele (OR = 6.70, 95% CI: 1.29-9.78) or MIF-173 C allele (OR = 6.54, 95% CI: 2.97-14.20) and positive for H. pylori infection. CONCLUSION: IL-8-251 and MIF-173 gene polymorphisms are significantly associated with the risk of SCAG and IM in a population with a high risk of GC in Linqu County, Shandong Province, China.

Pancreatic stromal Gremlin 1 expression during pancreatic tumorigenesis

Chronic pancreatitis(CP)is a major risk factor of pancreatic ductal adenocarcinoma(PDAC).How CP promotes pancreatic oncogenesis remains unclear.A characteristic feature of PDAC is its prominent desmoplasia in the tumor microenvironment,composed of activated fibroblasts and macrophages.Macrophages can be characterized as M1 or M2,with tumor-inhibiting or-promoting functions,respectively.We reported that Gremlin 1(GREM1),a key pro-fibrogenic factor,is upregulated in the stroma of CP.The current study aimed to investigate the expression of GREM1 and correlation between GREM1 and macrophages within the pancreas during chronic inflammation and the development of PDAC.By mRNA in situ hybridization,we detected GREM1 mRNA expression withinα-smooth muscle actin(SMA)-positive fibroblasts of the pancreatic stroma.These designated FibroblastsGrem1+marginally increased from CP to pancreatic intraepithelial neoplasia(PanIN)and PDAC.Within PDAC,FibroblastsGrem1+increased with higher pathological tumor stages and in a majority of PDAC subtypes screened.Additionally,FibroblastsGrem1+positively correlated with total macrophages(MacCD68+)and M2 macrophages(M2CD163+)in PDAC.To begin exploring potential molecular links between FibroblastsGrem1+and macrophages in PDAC,we examined the expression of macrophage migration inhibitory factor(MIF),an endogenous counteracting molecule of GREM1 and an M1 macrophage promoting factor.By IHC staining of MIF,we found MIF to be expressed by tumor cells,positively correlated with GREM1;by IHC co-staining,we found MIF to be negatively correlated with M2CD163+expression.Our findings suggest that GREM1 expression by activated fibroblasts may promote PDAC development,and GREM1/MIF may play an important role in macrophage phenotype.

Influence of functional polymorphism in MIF promoter on sudden cardiac death in Chinese populations

Sudden cardiac death(SCD)is defined as an unexpected natural death without any obvious non-cardiac causes that occurs within 1 h with witnessed symptom onset or within 24 h without witnessed symptom onset.Genetic studies conducted during the past decade have markedly illuminated the genetic basis of the cardiac disorders associated with SCD.Macrophage migration inhibitory factor(MIF)is an upstream immunoregulatory cytokine associated with the pathogenesis of many inflammatory diseases including atherosclerosis and myocardial infarction.Previous studies have reported that the functional -794(CATT)_(5-8) polymorphism in MIF is unrelated to sudden infant deth syndrome susceptibility.However,there are no reports concerning the association between the polymorphism and adult SCD susceptibility.In the current study,we investigated the association between the-794(CATT)_(5-8) polymorphism and adult SCD susceptibility using 79 adult SCD cases and 313 healthy controls.All samples were analysed using a conventional polymerase chain reaction(PCR)technique.We found that CATT_(6) and 5-6 were the most common allele and genotype in both groups,respectively,while no significant association was found between the-794(CATT)_(5-8) polymorphism and SCD susceptibility.We also summarized the allele frequencies of 794(CATT)_(5-8) in cohorts of healthy people from different countries and found that the allele frequency distributions of the polymorphism in Chinese populations were quite different from that of American and European populations(P=0.005,P=0.0001,respectively),but similar to Japanese populations(P=0.827).In conclusion,this study indicates that the-794(CATT)_(5-8) polymorphism may not be associated with adult SCD susceptibility in Chinese populations.Different allele frequency distributions of the polymorphism in multiple populations may provide a useful reference for further genetic association studies.