Macrophage migration inhibitory factor promotes renal injury induced by ischemic reperfusion

Macrophage migration inhibitory factor (MIF) is pleiotropic cytokine that has multiple effects in many inflammatory and immune diseases. This study reveals a potential role of MIF in acute kidney injury (AKI) in patients and in kidney ischemic reperfusion injury (IRI) mouse model in MIF wild‐type (WT) and MIF knockout (KO) mice. Clinically, plasma and urinary MIF levels were largely elevated at the onset of AKI, declined to normal levels when AKI was resolved and correlated tightly with serum creatinine independent of disease causes. Experimentally, MIF levels in plasma and urine were rapidly elevated after IRI‐AKI and associated with the elevation of serum creatinine and the severity of tubular necrosis, which were suppressed in MIF KO mice. It was possible that MIF may mediate AKI via CD74/TLR4‐NF‐κB signalling as mice lacking MIF were protected from AKI by largely suppressing CD74/TLR‐4‐NF‐κB associated renal inflammation, including the expression of MCP‐1, TNF‐α, IL‐1β, IL‐6, iNOS, CXCL15(IL‐8 in human) and infiltration of macrophages, neutrophil, and T cells. In conclusion, our study suggests that MIF may be pathogenic in AKI and levels of plasma and urinary MIF may correlate with the progression and regression of AKI.     

Effect of vitamin E on production of macrophage migration inhibitory factor (MIF) by macrophages

Macrophage migration inhibitory factor (MIF), a putative cytokine involved in inflammatory and immune responses, was identified in rat peritoneal macrophages by Western blot analysis and its secretion into culture medium by enzyme-linked immunosorbent assay. To clarify the possibility of vitamin E as an immune modulator, we investigated the effect of vitamin E on MIF production in macrophages in response to calcium ionophore A23187 and lipopolysaccharide (LPS). Intraperitoneal injections of vitamin E (5 mg per rat) for 6 successive days resulted in a significant increase of alpha-tocopherol content in peritoneal macrophages. Alpha-tocopherol content of macrophages in vitamin E-treated rats was 478.3 +/- 90.7 ng/10(6) cells, whereas in control rats it was 1.5 +/- 0.5 ng/10(6) cells. For the control macrophages, total MIF content of the medium (2.5 x 10(6) cells/18 ml) without stimulation was 40.7 +/- 3.6 ng after 14 h culture, whereas stimulation with calcium ionophore A23187 (400 nM) and LPS (5.0 microg/ml) induced the elevation of MIF content to 65.9 +/- 7.5 ng and 74.3 +/- 10.4 ng, respectively (p < 0.05, n = 3). On the other hand, vitamin E-enriched macrophages without stimulation showed less MIF content (14.0 +/- 4.2 ng) than the control (p < 0.05, n = 3). Similarly, the increase of MIF of vitamin E-treated macrophages was significantly suppressed after stimulation with calcium ionophore A23187 or LPS, compared with the control macrophages (p < 0.01, n = 3). From analysis of intracellular MIF content by Western blot, we found no alteration of intracellular MIF content of vitamin E-macrophages, in contrast to the decreased content of control stimulated-macrophages, showing that vitamin E suppressed MIF secretion into the culture medium. Taken together, these results indicate that vitamin E may contribute to the regulation of inflammatory and immune responses through regulation of MIF secretion, possibly by modulating macrophage-membrane architecture.     

Neuroendocrine properties of macrophage migration inhibitory factor (MIF)

The cytokine macrophage migration inhibitory factor (MIF) is produced by neuroendocrine and immune tissues and possesses several features that allow it to be characterized as a neuroendocrine mediator. Its pro-inflammatory action and its pathogenic role in inflammatory diseases, such as septic shock, arthritis and other diseases, have clearly been demonstrated and may be based in part on neuroendocrine mechanisms. Macrophage migration inhibitory factor possesses glucocorticoid-antagonist properties within the immune system and participates in the regulation of several endocrine circuits. This review summarizes the current state of MIF research and focuses on MIF expression and function in nervous and endocrine tissues.     

Inhibition of macrophage migration inhibitory factor (MIF) tautomerase activity by dopachrome analogs

A macrophage migration inhibitory factor (MIF) dopachrome tautomerization assay was employed for identification of MIF inhibitors. One group of dopachrome analogs was identified which inhibits MIF tautomerase activity. In particular, the analogs with a leaving group at beta position displayed activity at a concentration of tenfold less than that of the MIF-substrate. These findings could lead to a better understanding of MIF biological activities and the development of agents for the treatment of MIF related diseases.     

Production of macrophage migration inhibitory factor(s) (MIF) by virus-transformed cells

Rodent cell lines transformed by SV40, polyoma virus and Rous sarcoma virus cultured in vitro release material into the culture medium which inhibits the migration of guinea pig macrophages. Similar macrophage migration inhibitory factors (MIF) were not detected in cell-free supernatants harvested from untransformed cell cultures. Comparison of the MIF produced by virus-transformed cells with MIF derived from peripheral lymphocytes stimulated in vitro by phytohemagglutinin (PHA) revealed that they had similar molecular weights (25 000), heat stability and were both inhibited by α-fucose and lotus agglutinin. Incubation of MIF-containing cell-free supernatants from transformed cells with pancreatic trypsin inhibitor, soybean trypsin inhibitor and diisopropylfluorophosphate eliminated the MIF activity. The possible identity of the MIF released by transformed cells as a protease is discussed with reference to a potential role in modifying the surface properties of transformed cells.     

A novel androstenedione derivative induces ROS-mediated autophagy and attenuates drug resistance in osteosarcoma by inhibiting macrophage migration inhibitory factor (MIF)

Osteosarcoma is a common primary bone tumor in children and adolescents. The drug resistance of osteosarcoma leads to high lethality. Macrophage migration inhibitory factor (MIF) is an inflammation-related cytokine implicated in the chemoresistance of breast cancer. In this study, we isolated a novel androstenedione derivative identified as 3,4-dihydroxy-9,10-secoandrosta-1,3,5,7-tetraene-9,17-dione (DSTD). DSTD could inhibit MIF expression in MG-63 and U2OS cells. The inhibition of MIF by DSTD promoted autophagy by inducing Bcl-2 downregulation and the translocation of HMGB1. N-acetyl-L-cysteine (NAC) and 3-methyladenine (3-MA) attenuated DSTD-induced autophagy but promoted cell death, suggesting that DSTD induced ROS-mediated autophagy to rescue cell death. However, in the presence of chemotherapy drugs, DSTD enhanced the chemosensitivity by decreasing the HMGB1 level. Our data suggest MIF inhibition as a therapeutic strategy for overcoming drug resistance in osteosarcoma.Osteosarcoma, a common primary bone tumor in children and adolescents, is prone to early metastasis through blood.¹ Treatment with a combination of surgery and aggressive adjuvant chemotherapy has improved the survival rate of osteosarcoma patients. The 5-year-survival rates of non-metastatic patients have reached a plateau of approximately 70%.^{2, 3} However, patients with poor responses to chemotherapeutics will undergo local recurrence and metastasis, which reduce the 5-year-survival rates to only 20% despite additional doses or drugs.^{4, 5} Drug resistance is responsible for the poor prognosis. Attenuating chemoresistance facilitates better treatment of osteosarcoma.^{6, 7} Novel treatment strategies that combine anticancer drugs with adjuvant agents could improve the antitumor effects.^{8, 9}In the 1960s, macrophage migration inhibitory factor (MIF) was identified as a pluripotent protein that modulates inflammation.¹⁰ Increasing evidence suggests that inflammation is closely related to tumorigenesis.¹¹ MIF plays a bridging role between inflammation and tumorigenesis.^{12, 13, 14} MIF triggers the activation of the MAPK and PI3K pathways by binding its membrane receptor CD74, resulting in the inhibition of cell apoptosis.¹⁵ Recently, MIF was demonstrated to be involved in cell proliferation, differentiation, angiogenesis and tumorigenesis.^{16, 17, 18} Some evidence has indicated that MIF is abundantly expressed in various cancers and is significantly associated with tumor invasion and metastasis.^{19, 20, 21} MIF has been well established to be involved in the development of glioblastoma,²² breast cancer,²³ bladder cancer²⁴ and colon cancer.^{20, 25} MIF was also upregulated in osteosarcoma.^{26, 27} The knockdown of MIF blocked osteosarcoma cell proliferation and invasion.²⁶ However, the effect of MIF on drug resistance in osteosarcoma has not yet been investigated. Wu et al. ²³ have revealed that MIF knockdown promoted chemosensitivity by inducing autophagy in breast cancer. In contrast, autophagy reportedly contributed to chemoresistance in osteosarcoma.⁶ These controversial results prompted us to confirm the role of MIF in drug resistance in osteosarcoma.In this study, we isolated a novel androstenedione derivative identified as 3,4-dihydroxy-9,10-secoandrosta-1,3,5,7-tetraene-9,17-dione (DSTD). DSTD could inhibit MIF expression in MG-63 and U2OS cells. Both N-acetyl-L-cysteine (NAC) and 3-methyladenine (3-MA) attenuated DSTD-induced autophagy but promoted cell death, suggesting that DSTD induced reactive oxygen species (ROS)-mediated autophagy to rescue cell death. Furthermore, MIF inhibition by DSTD enhances chemosensitivity by downregulating HMGB1 in osteosarcoma cells. Our data suggest MIF inhibition as a therapeutic strategy for overcoming drug resistance in osteosarcoma.     

Antisense macrophage migration inhibitory factor (MIF) prevents anti-IgM mediated growth arrest and apoptosis of a murine B cell line by regulating cell cycle progression

Macrophage migration inhibitory factor (MIF) is involved in the generation of cell-mediated immune responses. Recently it has been reported that MIF also plays a role in cell proliferation and differentiation. In the present study, using a B-cell line, WEHI-231, and its stable MIF-antisense transfectant, WaM2, as a representative transfectant, we investigated the mechanism underlying regulation of the cell growth by MIF. WaM2 cells produced less MIF than vector control or parental WEHI-231 cells. Reduced and increased proportions were seen in G1 and S-phase cells, respectively, in WaM2 as compared with WEHI-231. Growth arrest and apoptosis after stimulation via surface Ig (sIg) were less prominent in WaM2 cells than those in WEHI-231. However, the addition of recombinant rat MIF did not reverse the inhibition of the growth arrest and apoptosis induced in WaM2 by cross-linking sIg. Almost the same amount of p27kip1 expression was detected in WaM2 cells as those in WEHI-231 and vector control cells. Cross-linking of sIg elevated the p27kip1 level equally in these cells irrespective of the MIF-antisense expression. Taken together, it seems that MIF plays a role in inducing apoptosis in B cells upon IgM cross-linking by regulating the cell cycle via a novel intracellular pathway.     

胰腺癌组织中巨噬细胞移动抑制因子的表达及其意义

目的研究巨噬细胞移动抑制因子（MIF）在胰腺癌发生发展中的作用,与肿瘤标志物CEA、CA199的关系。方法应用免疫组化方法检测31例胰腺癌组织、癌旁组织以及14例正常胰腺组织中MIF表达水平,分析MIF表达与各项临床病理特点及血清CEA、CA199水平的关系。结果 MIF在胰腺癌组织中的表达为87.1%,高于癌旁组织的54.8%和正常胰腺组织的7.4%（P〈0.01）;癌旁组织的MIF表达高于正常组织（P〈0.01）。MIF的表达与肿瘤分化程度及远处转移有关（P〈0.05）,MIF表达阳性患者的血清CA199水平高于MIF表达阴性患者,而血清CEA水平两组间无显著统计学意义。结论 MIF对胰腺癌的发生发展起重要作用,可能促进正常腺体组织向胰腺癌发生和发展。MIF可作为胰腺癌的一种血清标志物,联合CA199的检测可更好的发现胰腺癌。     

Possible role of macrophage glycolipids as receptors for migration inhibitory factor (MIF).

Guinea pig peritoneal exudate cells incubated with water soluble glycolipids obtained from macrophages show an enhanced response to migration inhibitory factor. Incorporation of these glycolipids into liposomes greatly facilitates their interaction with indicator cells. Enhancement of peritoneal exudate cell responsiveness to migration inhibitory factor was specific for glycolipids from guinea pig macrophages. Glycolipids extracted from guinea pig brain and polymorphonuclear leukocytes as well as several bovine and porcine glycolipids had no effect. Specificity of enhancement was not due merely to a preferential association of macrophage glycolipids with indicator cells. The possible role of macrophage glycolipids as receptors for MIF is discussed.     

Involvement of macrophage migration inhibitory factor (MIF) in experimental uric acid nephropathy

BACKGROUND: Deposition of uric acid in the kidney can lead to progressive tubulointerstitial injury with granuloma formation. We hypothesized that uric acid crystal deposition may induce granuloma formation by stimulating local expression of macrophage migration inhibitory factor (MIF), which is a known mediator of delayed type hypersensitivity (DTH). MATERIALS AND METHODS: A model of acute uric acid nephropathy was induced in rats by the administration of oxonic acid (an inhibitor of uricase), together with uric acid supplements. MIF expression and local cellular response were examined by in situ hybridization and immunohistochemistry. RESULTS: Kidney tissue examined at 35 days posttreatment showed widespread tubulointerstitial damage with intratubular uric acid crystal deposition and granuloma formation. Tubules within the areas of granuloma showed a six-fold increase in MIF mRNA, compared with uninvolved areas by in situ hybridization. Moreover, the areas of increased MIF mRNA expression correlated with sites of dense accumulation of macrophages and T cells, and these cells were activated when assessed by the expression of interleukin-2R (IL-2R) and (MHC) class II. Interestingly, cytoplasmic staining for MIF protein in the uric acid (UA) crystal-associated granulomatous lesions was reduced, indicating a rapid MIF secretion by damaged tubules and macrophages secondary to uric acid crystal stimulation. This was confirmed by the demonstration of a marked increase in urinary MIF protein by Western blot analysis. Control rats fed either a normal diet or only oxonic acid had no discernible evidence of renal disease by routine light microscopy and minimal tubular expression of MIF mRNA and protein. CONCLUSIONS: These data suggest that intrarenal granulomas in urate nephropathy may be the consequence of a crystal induced DTH reaction mediated by MIF.     

Macrophage migration inhibitory factor (MIF) promotes rat airway muscle cell proliferation and migration mediated by ERK1/2 and FAK signaling

Macrophage migration inhibitory factor (MIF) is an inflammatory mediator that contributes to asthmatic airway remodeling; however, little is known regarding the effects of MIF on airway smooth muscle cells (ASMCs). In the present study, we found that an enhanced expression of MIF promoted ASMC proliferation, increased the population of cells in the S/G2 phase, downregulated P21 expression, and upregulated cyclin D1, cyclin D3, and Cdk6 expression. In addition, the apoptosis of ASMCs was significantly decreased in response to MIF overexpression, compared with the negative control. Moreover, MIF facilitated the migration of ASMCs by upregulating the expression of matrix metalloproteinase (MMP)‐2. Finally, we showed that MIF increased the phosphorylation of extracellular regulated protein kinases (ERK) 1/2 and focal adhesion kinase (FAK), which are associated with proliferation and migration. In conclusion, this study demonstrated that MIF overexpression promotes the proliferation and migration of ASMCs by upregulating the activity of the ERK1/2 and FAK signaling pathways in these cells, further indicating that inhibition of MIF may prove to be an effective strategy for treating asthma patients with airway remodeling.     

Re-examining the oligomerization state of macrophage migration inhibitory factor (MIF) in solution

The state of oligomerization of macrophage migration inhibitory factor (MIF, also known as glycosylation inhibiting factor, GIF) in solution has been variously reported as monomer, dimer, trimer, or mixtures of all three. Several crystal structures show MIF to be a trimer. Sedimentation velocity shows a recombinant human MIF sample is quite homogeneous, with 98% as a species with s(20,w)=3.07 S and D(20,w)=8.29 x 10(-7) cm(2)/s. Using the partial specific volume calculated from the amino acid composition these values imply a mass of 33.56 kDa, well above that of dimer, but also 9% below the trimer mass of 37.035 kDa. Sedimentation equilibrium data at loading concentrations from 0.01 to 1 mg/ml show unequivocally that the self-association is extremely tight. However, the apparent mass is 33.53 kDa [95% confidence 33.25-33.82], again 9% below that expected for 100% trimer. To examine the possibility this protein has an unusual partial specific volume, sedimentation equilibrium was also done in H(2)O/D(2)O mixtures, giving 0.765+/-0.017 ml/g rather than the calculated 0.735 ml/g. With this revised partial specific volume, the equilibrium and velocity data each give M=37.9+/-2.8 kDa, fully consistent with a strongly-associated trimeric quaternary structure.     

Early release of macrophage migration inhibitory factor after liver ischemia and reperfusion injury in rats

Macrophage migration inhibitory factor (MIF) is an important mediator of ischemia/reperfusion (I/R) injury in heart, brain and intestine. We previously demonstrated that MIF was released during warm/cold ischemia in vitro. However, the role of MIF in liver I/R injury remains unclear. We aimed to test the hypothesis that MIF acts as an early proinflammatory cytokine and could mediate the inflammatory injury in liver I/R. Rats (n = 6 per group) were subjected to 90 min warm ischemia followed by 0.5 h, 6 h and 24 h reperfusion, respectively to liver transplantation (LTx) after 6 h of cold ischemia followed by 24 h of reperfusion. The expression of MIF, its receptor (cluster of differentiation 74 (CD74)) and the downstream inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin-1 beta (IL-1β)) were analyzed. Peritoneal macrophages were cultured for 6 h alone or in the presence of effluent from cold-preserved livers or effluent depleted of MIF. Warm I/R increased hepatic MIF-mRNA and protein expression. MIF-protein was released into peripheral circulation in vivo with a maximum at 0.5 h after reperfusion. Induction of MIF-expression was associated with the expression of proinflammatory cytokines and its receptor in both models. MIF released by isolated cold preserved livers, induced TNF-α and IL-1β production by cultured peritoneal macrophages. Intrahepatic upregulation of MIF, release into systemic circulation and the associated upregulation of the proinflammatory mediators suggest a role of MIF in mediating the inflammatory response to I/R injury. Blocking experiments will help to elucidate its role as potential molecular target for preventing hepatic I/R injury.     

Chemical treatment of macrophages increases their responsiveness to migration inhibitory factor (MIF).

The response of guinea pig macrophages to migration inhibitory factor (MIF) is altered by several chemical treatments. Treatment of macrophages with the diazonium salt of sulfanilic acid (5 x 10(-6) to 4 x 10(-4) M) significantly increases the response of these cells to MIF. Treatment with acetic anhydride also augments the response of these cells to MIF. The latter finding suggests that alteration of amino, hydroxyl, or sulfhydryl groups is involved in this phenomenon. Treatment of macrophages with sodium periodate (2 x 10(-5) to 10(-3) M) which is known to oxidize cis-glycols and with hydroxylamine (2 x 10(-5) to 2 x 10(-3) M), which reacts with carbonyl groups also increases response to MIF. The following experiments suggest that the significant alteration occurs at the level of the cell surface. Incubation of macrophages with the diazonium salt of sulfanilic acid at 4 degrees C, at which temperature pinocytosis is largely inhibited, is sufficient to increase the MIF response. The activity of the cytoplasmic enzyme aspartate aminotransferase, which in homogenates is susceptible to inactivation by low concentrations of the diazonium salt of sulfanilic acid, is not decreased when intact macrophages are incubated with high concentrations of the diazonium salt of sulfanilic acid. Cumulatively, these findings suggest that modification of different functional groups on the macrophage surface causes the same physiologic effect.