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.

Macrophage migration inhibitory factor as a potential prognostic factor in gastric cancer

AIM:To investigate macrophage migration inhibitory factor(MIF) expression and its clinical relevance in gastric cancer,and effects of MIF knockdown on proliferation of gastric cancer cells. METHODS:Tissue microarray containing 117 samples of gastric cancer and adjacent non-cancer normal tissues was studied for MIF expression by immunohistochemistry(IHC) semiquantitatively,and the association of MIF expression with clinical parameters was analyzed. MIF expression in gastric cancer cell lines was detected by reverse transcriptionpolymerase chain reaction(RT-PCR) and Western blot. Two pairs of si RNA targeting the MIF gene(MIF si-1 and MIF si-2) and one pair of scrambled si RNA as a negative control(NC) were designed and chemically synthesized. All si RNAs were transiently transfected in AGS cells with OligofectamineTM to knock down the MIF expression,with the NC group and mock group(OligofectamineTM alone) as controls. At 24,48,and 72 h after transfection,MIF m RNA was analyzed by RTPCR,and MIF and proliferating cell nuclear antigen(PCNA) proteins were detected by Western blot.The proliferative rate of AGS cells was assessed by methylthiazolyl tetrazolium(MTT) assay and colony forming assay.RESULTS:The tissue microarray was informative for IHC staining,in which the MIF expression in gastric cancer tissues was higher than that in adjacent noncancer normal tissues(P < 0.001),and high level of MIF was related to poor tumor differentiation,advanced T stage,advanced tumor stage,lymph node metastasis,and poor patient survival(P < 0.05 for all). After si RNA transfection,MIF m RNA was measured by real-time PCR,and MIF protein and PCNA were assessed by Western blot analysis. We found that compared to the NC group and mock group,MIF expression was knocked down successfully in gastric cancer cells,and PCNA expression was downregulated with MIF knockdown as well. The cell counts and the doubling times were assayed by MTT 4 d after transfection,and colonies formed were assayed by colony forming assay 10 d after transfection; all these showed significant changes in gastric cancer cells transfected with specific si RNA compared with the control si RNA and mock groups(P < 0.001 for all).CONCLUSION:MIF could be of prognostic value in gastric cancer and might be a potential target for small-molecule therapy.

Early treadmill exercise increases macrophage migration inhibitory factor expression after cerebral ischemia/reperfusion

The neuroprotective function of macrophage migration inhibitory factor(MIF) in ischemic stroke was rarely evaluated.This study aimed to investigate the effects of early treadmill exercise on recovery from ischemic stroke and to determine whether these effects are associated with the expression levels of MIF and brain-derived neurotrophic factor(BDNF) in the ischemic area.A total of 40 male Sprague-Dawley rats were randomly assigned to the ischemia and exercise group [middle cerebral artery occlusion(MCAO)-Ex,n = 10),ischemia and sedentary group(MCAO-St,n = 10),sham-surgery and exercise group(Sham-Ex,n= 10),or sham-surgery and sedentary group(Sham-St,n = 10).The MCAO-Ex and MCAO-St groups were subjected to MCAO for 60 minutes,whereas the Sham-Ex and Sham-St groups were subjected to an identical operation without MCAO.Rats in the MCAO-Ex and Sham-Ex groups then ran on a treadmill for 30 minutes once a day for 5 consecutive days.After reperfusion,the hanging time tested by the wire hang test was longer and the relative fractional anisotropy determined by MRI was higher in the peri-infarct region of the MCAO-Ex group compared with the MCAO-St group.The expression levels of MIF and BDNF in the peri-infarct region were upregulated in the MCAO-Ex group.Increased MIF and BDNF levels were positively correlated with relative fractional anisotropy changes in the peri-infarct region.There was no significant difference in the levels of MIF and BDNF in the peri-infarct region between the Sham-Ex and Sham-St groups.Our study demonstrated that early exercise(initiated 48 hours after the MCAO) could improve motor and neuronal recovery after ischemic stroke.Furthermore,the increased levels of MIF and BDNF in the peri-infarct region(penumbra) may be one of the mechanisms of enhanced neurological function recovery.All experiments were approved by the Institutional Animal Care and Use Committee in Asan Medical Center in South Korea(2016-12-126).

Serum and ascites levels of macrophage migration inhibitory factor, TNF-α and IL-6 in patients with chronic virus hepatitis B and hepatitis cirrhosis

Objective: To study the potential role of macrophage migration inhibitory factor (MIF), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the development of chronic virus hepatitis B (CH) and hepatitis cirrhosis (HC). Methods: The serum concentrations of MIF, TNF-α and IL-6 in 18 patients with chronic virus hepatitis B and in 14 patients with hepatitis cirrhosis without as- citic fluid, and the serum and ascites cytokine con- centrations in 22 HC patients with ascitic fluid were detected by enzyme linked immunity sorbed assay. Results: The cytokine concentrations of the patients were significantly higher than those of the controls. The serum levels of MIF, TNF-α and IL-6 of the 22 patients with ascitic fluid were higer than those of 14 HC patients without ascites. In the 18 patients with CH, the serum cytokine concentrations were the low- est. The serum cytokine concentrations of the 22 HC patients with ascites were significantly higher than those of the 14 HC patients without ascites (P< 0. 01). Their serum cytokine concentrations were sig- nificantly higher than those in the 18 patients with CH (P<0. 01). The concentration of IL-6 in ascites was the highest among all the groups. The serum le- vels of MIF, TNF-α and IL-6 are correlated with al- anine aminotransferase (ALT) in the patients with CH, but not in those with HC with or without asci- tes. Conclusions: These results indicated that MIF, TNF- α and IL-6 may participate in the pathological process of CH and cirrhosis, that IL-6 seems to play an important role in ascites formation, and that se- rum levels of MIF, TNF-α and IL-6 appear to reflect the severity of tissue injury in HBV disease.

Cloning and mRNA expression of macrophage migration inhibitory factor (MIF) gene of large yellow croaker (P seudosciaena crocea)

Mammalian macrophage migration inhibitory factor （MIF） plays an important role as an indispensable mediator in the pathogenesis of inflammatory disease like septicemia, but little is known about the role of MIF homologue in fish septicemia. The authors have cloned the MIF homologue in large yellow croaker Pseudosciaena crocea （LycMIF） using RACE approach. The full-length cDNA of LycMIF was 634 bases and contained an ORF of 345 bases encoding a protein of 115 amino acid residues. As demonstrated by RT-PCR and QRT-PCR assay, MIF mRNAs were constitutively expressed in 11 selected tissues and were abundant in brain and liver. Moreover, the LycMIF transcripts in the liver and head kidney were responsive to bacteria infection and could be significantly up-regulated. Our results provide the first direct evidence that fish MIF was implicated in pathogenesis of fish vibrosis and play an important role in response to bacteria infection.

Macrophage migration inhibitory factor regulates proliferation of gastric cancer cells via the PI3K/Akt pathway

AIM:To investigate the effects of macrophage migration inhibitory factor (MIF) on proliferation of human gastric cancer MGC-803 cells and expression of cyclin D1 and p27Kip1 in them,and further determine whether the effects are related to the PI3K/Akt signal transduction pathway. METHODS:Gastric cancer MGC-803 cells were cultured and then treated with 50 μg/L recombinant human MIF (rhMIF) with and without a PI3K inhibitor,LY294002 (25 μmol/L). MTT assay was used to detect the prolifer-ation of MGC-803 cells. Cell cycle was detected by flow cytometry. Expression of cyclin D1 and p27Kip1 mRNA was by reverse transcription-polymerase chain reaction. Protein expression of phosphorylated Akt (p-Akt),Akt,cyclin D1 and p27Kip1 was examined by immunocyto-chemistry and Western blotting. RESULTS:rhMIF signifi cantly stimulated the prolifera-tion of MGC-803 cells and cell cycle progression from G1 phase to S phase in a concentration-and time-de-pendent manner. After the MGC-803 cells were treated with rhMIF for 24 h,the expression of cyclin D1 was signifi cantly up-regulated compared with the cells not treated with rhMIF at both mRNA and protein levels(0.97 ± 0.02 vs 0.74 ± 0.01,P = 0.002; 0.98 ± 0.05 vs 0.69 ± 0.04,P = 0.003). The p27Kip1 was down-regulated but only statistically significant at the protein level. rhMIF significantly increased the expression of p-Akt,which reached the peak at 30 min,but did not affect the expression of Akt. However,LY294002 inhibited all the effects of rhMIF.CONCLUSION:Macrophage MIF increases the proliferation of gastric cancer cells,induces the expression of cyclin D1 at the transcriptional level and inhibits the expression of p27Kip1 at the post-transcriptional level via the PI3K/Akt pathway.

Upregulation of macrophage migration inhibitory factor and calgizzarin by androgen in TM4 mouse Sertoli cells

Aim： To identify proteins induced by androgen in Sertoli cells during spermatogenesis. Methods： We analyzed protein profiles in TM4 Sertoli cells treated with dihydrotestosterone （DHT） using surface enhanced laser desorption ionization time-of-flight mass spectrometry （SELDI-TOF-MS）. Results： We found increases in the expression of a 5.0-kDa protein at 15 min, an 11.3-kDa protein at 24 h and 4.3 kDa, 5.7 kDa, 5.8 kDa, 9.95 kDa and 9.98 kDa proteins at 48 h after the treatment. In contrast, the expression of 6.3 kDa and 8.6 kDa proteins decreased at 30 min, and 4.9 kDa, 5.0 kDa, 12.4 kDa and 19.8 kDa proteins at 48 h after the treatment. The ll.3-kDa protein was identified as macrophage migration inhibitory factor （MIF） known to having various functions. The 9.98-kDa protein was identified as calgizzarin related to calcium channels. The timing of their expression suggests that MIF and calgizzarin are involved in late regulation of spermatogenesis in Sertoli cells by androgen. Conclusion： MIF and calgizzarin are two important androgen-responsive proteins produced by Sertoli cells and they might play a role in regulating spermatogenesis.

Expression of macrophage migration inhibitory factor in Aspergillus fumigatus keratitis

AIM: To investigate the expression of macrophage migration inhibitory factor(MIF) and detect its role in the innate immune response of fungal keratitis(FK). METHODS: We collected the paraffin-embedded cornea tissues from 10 FK and 6 ocular trauma patients to explore the MIF expression by immunohistochemistry. Then we cultured telomease-immortalized human corneal epithelial cells(THCEs), stimulated by the hyphae suspension of Aspergillus fumigatus(A. fumigatus) to detect the change of MIF with or without the pretreatment of MIF inhibitor [4-Iodo-6-phenylpyrimidine(4-IPP)] by real-time polymerase chain reaction(PCR). The protein level of MIF was also tested by immunohistochemistry, and the level of tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) mRNA were compared between normal, hyphae stimulated and 4-IPP pretreated groups by real-time PCR to study the influence of MIF on the expression of TNF-α and IL-6. Corneal severity of rats' FK models was documented by clinical scores, and real-time PCR. Western blot and immunohistochemistry were used to test the expression of MIF, TNF-α and IL-6 in rats' corneas.RESULTS: In the corneas of FK patients, there was much stronger expression of MIF than that in the normal group showed by immunohistochemistry. In cultured THCEs stimulated by A. fumigatus, the expression of MIF became stronger in both immunohistochemistry and PCR at 16, 24, 32 and 48 h post infection(p.i.; P<0.01, P<0.01, P<0.01, P<0.05). After pretreated with 4-IPP, the expression of MIF reduced at 4, 8, 16 h p.i.(P<0.05, P<0.05, P<0.05) and the downstream TNF-α and IL-6 decreased obviously(P<0.05, P<0.01). In rats with A. fumigatus keratitis, the relative mRNA and protein level of MIF increased than thosein the normal group by PCR(at 1 d: P<0.01, 3 d: P<0.01, 5 d: P<0.01), Western blot and immunohistochemistry. After blocked MIF with 4-IPP, the clinical outcomes of rat keratitis showed markedly reduced inflammatory response(P<0.01), with TNF-α and IL-6 decreased in accordance with those in THCEs by PCR(P<0.05, P<0.01). CONCLUSION: The expression of MIF increased significantly in FK patients, THCEs and rats stimulated by A. fumigatus. After blocked with 4-IPP, the expression of MIF reduced, and so did its downstream cytokines: TNF-α and IL-6. The inflammation reaction of the rats' corneas lightened after pretreated with 4-IPP. MIF may play a role in the innate immune response of the corneal resistance against A. fumigatus.

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（8） polymorphism, respectively. RESULTS： The MIF levels in plasma were significantly higher in patients with lacrimal gland BI.EL 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% C1=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 BLEI. 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 （） 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.

Effects of antisense oligonucleotides on theexpression of macrophage migration inhibitoryfactor on macrophages

To investigate the effects of antisense oligonucleotides on the expression of macrophage migration inhibitory factor (MIF) on macrophages, the mouse phosphorothioate oligonucleotides were designed and synthesized with the sequences of antisense, 5′-TACGGATACAAGTAGCAC-3′; Sense, 5′-ATGCCTATGTTCATCGTG-3′; Missense, 5′-CTCTCAGACTCGATCTGT-3′. These phosphorothioate oligonucleotides were then transfected into cultured macrophages ( RAW264.7 ) by luciferase vector, and the transfected macrophages were incubated with Lipopolysaccharide (LPS) (1?ng/ml) for various periods of times and collected afterwards. The content of MIF protein in the cultural supernatants was determined by ELISA, cellular RNA extracted and the expression of MIF mRNA was examined by RT-PCR analysis. The experimental results showed that LPS could induce a time-dependent specific expression of MIF on macrophages, in which the MIF mRNA in cells and the MIF protein in cultural supernatants appeared after 3 h and reached their highest concentration at 9-12?h after LPS stimulation. The levels of mRNA and proteins in the macrophages treated with antisense olignucleotides were decreased significantly after stimulation with LPS in comparison with that of stimulation with LPS alone or with that with LPS plus sense or missense oligonucleotides. There were no differences among those without LPS stimulation. It is concluded that macrophages stimulated with LPS express MIF, and the antisense olignucleotides of MIF inhibit the expression of MIF mRNA as well as the secretion of MIF proteins in macrophages.

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.

Pathogenesis of coxsackievirus B3-induced myocarditis： role of macrophage migration inhibitory factor

Background Macrophage migration inhibitory factor （MIF） is an upstream regulator in immune and inflammatory responses.However,its role in viral myocarditis remains unknown.In this study,we investigated the role of the MIF in coxsackievirus B3 （CVB3）-induced myocarditis.Methods Mice were randomized into two groups receiving either Eagle＇s minimal essential medium （EMEM,control group） or virus solution （infected group）.Subsets of mice in the infected group were sacrificed on days 3,7,14 and 28 after inoculation.Expression of MIF was detected using an enzyme-linked immunosorbent assay （ELISA）,reverse transcription polymerase chain reaction and immunohistochemistry.A neutralizing antibody （Ab） to MIF was injected intraperitoneally from day 0 to 7 after inoculation.Disease severity was estimated by histopathology of the heart and by the heart weight to body weight ratio,and the interleukin-1β （IL-1β） and tumor necrosis factor α （TNF-α） in the myocardium were measured by ELISA on day 14.Results The serum MIF concentration and expression levels of myocardial MIF mRNA and protein were significantly elevated in mice on days 7 and 14 post-infection.The survival rate was markedly higher and disease severity was obviously less in mice treated with anti-MIF Ab.Furthermore,MIF blockade significantly decreased the IL-1β and TNF-α in the myocarditic heart.Conclusion These results demonstrate that MIF is an important naturally occurring inflammatory cytokine in CVB3-induced myocarditis,and anti-MIF Ab may lessen the inflammatory response.

The effect of Helicobacter pylori infection on expression of macrophage migration inhibitory factor by T cells and macrophages in gastric mucosa

Background Macrophage migration inhibitory factor (MIF) plays a pivotal role in inflammatory and immune-mediated diseases. However, its molecular function and role in gastrointestinal diseases has rarely been studied and thus warrants an in-depth investigation. This study was designed and conducted to determine MIF expression in Helicobacter pylori (H. pylori)-induced gastritis and the effect of H. pylori on MIF expression in monocytes in vitro. Methods Gastric specimens of 62 patients with chronic gastritis were obtained through endoscopic biopsies. Both gastric antrum and body were examined for histopathologic changes. Positive H. pylori was determined through rapid urease test and histopathological examination. A patient was classified as H. pylori positive if both tests showed positive results. The updated Sydney System was employed to assess the severity and activity of gastric inflammation. Double immunoassaying for MIF/T-cells (CD45RO) and MIF/macrophage (KP1), as well as in situ hybridization for the expression of MIF mRNA were used for the current analysis. THP-1, a monocyte cell line, was co-incubated with H. pylori strains (ATCC26695) and subsequently examined for the expression of MIF protein and mRNA by enzyme linked immunosorbent assay and retrospective transcription-polymerase chain reaction, respectively. Results Among 62 patients with chronic gastritis, significant increase in total T-cells, MIF+ T-cells, total macrophages, MIF+ macrophages and MIF mRNA+ cells was observed in 42 H. pylori positive patients compared to H. pylori negative patients. Moreover, the increase of the MIF mRNA+ cells was highly correlated with the severity of the disease(number of MIF mRNA+cells/mm2, mild: 2834±382, moderate: 3569±123, severe: 3881±118, P<0.01). In vitro results showed that the expression of MIF protein and mRNA in monocytes was significantly increased after incubation with H. pylori strains.Conclusions Overexpression of MIF is common in H. pylori-induced gastric inflammation, which suggests MIF may play an important role in the initiation and development of this disease.

Autophagy mediates the secretion of macrophage migration inhibitory factor from cardiomyocytes upon serum-starvation

Macrophage migration inhibitory factor(MIF) is an inflammatory cytokine. It is elevated early in the blood of acute myocardial infarction patients. However, it is unclear whether and how MIF is released. This study investigated the cellular source and mechanism of MIF release from hearts. An ischemia-mimic treatment induced the secretion of MIF from neonatal rat cardiomyocytes but not from fibroblasts. The treatment did not cause significant leakage of lactate dehydrogenase, suggesting that ischemia induced the MIF secretion without causing severe cell damage. Plasma samples from patients with acute chest pain at the emergency department were collected for the detection of MIF. MIF levels in patients with acute coronary syndrome(ACS)increased early, when cardiac injury markers were not yet elevated, suggesting that ischemia can induce MIF secretion before the occurrence of severe myocardial damage. Serum-starvation caused MIF secretion from rat cardiomyocytes and Langendorffperfused rat hearts. The secretion was suppressed by the inhibition of autophagy by inhibitors or by silencing of Atg5. In conclusion, serum-starvation induces the secretion of MIF from cardiomyocytes via autophagy dependent pathway. Clarifying the mechanism of MIF secretion will be helpful for its application in the early diagnosis and treatment of ACS.

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 promotes the expression of GLUT4 glucose transporter through MEF2 and Zac1 in cardiomyocytes

Background Evidences show that macrophage migration inhibitory factor （MIF） and the subtype 4 form of glucose transporter （GLUT4） participate in the process of diabetic cardiomyopathy （DCM）, however the effect of MIF on modulation of GLUT4 expression is not clear. The present study aimed to investigate the mechanism underlying the modulation of GLUT4 by MIF in cardiomyocytes. Methods The neonatal C57BL/ 6 mouse ventricular cardiomyocytes （NMVCs） were isolated for in vitro studies. Expressions of GLUT4 and the candidate GLUT4 regulation associated transcription factors in mouse myocardium and NMVCs were determined by quantitative reverse transcription PCR （qRT-PCR）, and Western blotting, respectively. The effects of screened transcription factors on mediating MIF-promoted GLUT4 expression were verified by RNA interference （RNAi） assay. Results MIF was upregulated, but GLUT4 was decreased in the diabetic myocardium of the db/db mice. MIF could enhance glucose uptake of the cultured neonatal mouse cardiomyocytes with significant upregulation of GLUT4. RT-qPCR and Western-blot assays showed that MEF2A, -2C, -2D and Zacl were significantly up-regulated in MIF-treated NMVCs. Knockdown of Zacl, MEF2A, -2C, and -2D could markedly inhibit glucose uptake and GLUT4 expression in cardiomyocytes. Moreover, Zacl was also shown directly regulated by MEF2A, -2C, and -2D, respectively. Conclusions Transcription factors Zacl and MEF2 mediate MIF-promoted GLUT4 expression in cardiomyocytes.

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 C57BL/6 mice, and the cardiac fibroblasts from passage 2 to 4 were used in this study. Expression of fibrosis-associated Collal, Col3al and oL-SMA in mouse cardiac fibroblasts was de- tected by immunofluorescence staining and Western-blot assay, respectively. Intracellular oxidants in mouse car- diac fibroblasts were measured by using the probe dichlorofluoroscindiacetate （DCFH-DA） under confocal mi- croscopy. 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 Collal, Col3al and oL-SMA expression in cardiac fibroblasts. DCFH- DA 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-l, SOD2, Trx-2 and e-NOS, were increased in MIF-treated cardiac fibroblasts. MLL and HCF-lwere up-regulated by MIF, and either MLL knockdown or HCF-1 knock- down could consistently suppress Nrf2 expression in cardiac fibroblasts. Conclusions MIF possesses anti-fibro- sis effect by inactivating Smad3 and activating Nrf2 in cardiac fibroblasts.