Degradation of Melanotropin Inhibiting Factor by Brain

Degradation of melanotropin inhibiting factor (MIF) was measured by fluorometry, using pareptide as an internal standard, following the separation of the dansyl derivatives of MIF and its metabolites by HPLc. MIF was not split by carboxypeptidases A and B, prolidase, or pyroglutamate aminopeptidase. It was hydrolyzed by leucine aminopeptidase, aminopeptidase M, and carboxypeptidase Y. Rat brain hydrolyzed 159 nmol of MIF per mg of protein per h; the activity was linear with enzyme concentration. Hydrolysis start from the N-terminal end, as shown by the appearance of proline as the first metabolite of the MIF degradation, followed by leucine, glycinamide, leucylglycine, and glycine. Activity in the rat brain regions was in the order striatum, medulla oblongata > cortex, hippocampus, midbrain > hypothalamus, cerebellum, and pituitary. The enzyme was mostly in the supernatant, with significant amounts in the myelin and synaptosomal fractions. MIF aminopeptidase could be separated from carboxypeptidase by centrifugation at 30,000 x g for 20 min and precipitation with 45--75% (NH4)2SO4. It showed pH optima in the alkaline range (8.25 and 8.75) and was inhibited by EDTA, EGTA, SQ 14,225, puromycin, bacitracin, and bestatin.     

Biologic activity of extracts of delayed hypersensitivity skin reaction sites

Extracts obtained from skin sites of delayed hypersensitivity reactions show chemotactic activity for monocytes and lymphocytes but not neutrophils. The soluble extractable factors present at these sites have in vivo activity as well; they promote the accumulation of monocytes in peritoneal exudates and cause inflammatory reactions in the skin of nonimmunized animals. The skin inflammatory infiltrates are predominantly mononuclear and are similar to those of delayed hypersensitivity reactions in actively immunized guinea pigs. The extracts which produced these effects had no detectable MIF activity, nor permeability inducing activity in excess of that obtainable from normal skin.These monocyte and lymphocyte chemotactic factors were analyzed by sucrose density ultracentrifugation. By this technique the distribution of monocyte factors corresponded rather closely with that of the monocyte chemotactic factors obtained from an antigen-activated lymphocyte culture. Similar correspondence was obtained for the bulk of the lymphocyte chemotactic activity present in skin extracts and in culture supernatants. This suggests the possibility that the lymphokine-like substances in the skin extracts might in fact represent lymphokines. Further documentation of this point will provide a link between in vitro and in vivo manifestations of delayed hypersensitivity.     

亚慢性地卓西平诱导的精神分裂样小鼠前额叶和海马脑区MIF蛋白表达的变化

目的:探讨亚慢性地卓西平(MK-801)诱导的精神分裂样小鼠模型中前额叶和海马脑区巨噬细胞迁移抑制因子(Macrophage migration inhibitory factor,MIF)蛋白表达的变化。方法:将24只7周龄小鼠随机分为对照组、MK-801组和MK-801+奥氮平(olanzapine,olz)组(n=8),三组小鼠分别接受0.9%生理盐水、MK-801(0.6 mg/kg)和MK-801(0.6 mg/kg)+奥氮平(2.5 mg/kg)给药,持续4周。小鼠行为学通过旷场试验、社交实验进行评价,免疫印迹法检测小鼠前额叶和海马组织中MIF蛋白的表达。结果:MK-801处理后,小鼠活动量增加,社交功能受损,且都能被抗精神分裂症药物奥氮平显著改善。MK-801组小鼠前额叶皮层中MIF蛋白表达与对照组比较无明显统计学差异(P0.05),而海马脑区中MIF蛋白表达较对照组明显升高(P0.05);MK-801+奥氮平组小鼠前额叶皮层中MIF蛋白表达较MK-801组无显著变化,而海马脑区中MIF蛋白表达较MK-801组明显降低(P0.05)。结论:亚慢性给予MK-801诱导的精神分裂样小鼠海马脑区中MIF蛋白水平升高,提示MIF蛋白可能参与MK-801诱导的精神分裂样行为。     

Macrophage migration inhibitory factor increases cell motility and up-regulates αvβ3 integrin in human chondrosarcoma cells

The macrophage migration-inhibitory factor (MIF) is a pro-inflammatory cytokine first known for its effect on macrophage migration and activation. Recent studies have shown that MIP plays a critical role in tumor growth, angiogenesis, and metastasis. Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. However, the effects of MIF on human chondrosarcoma cells are largely unknown. In the present study, MIF was found to increase the migration and the expression of αvβ3 integrin in human chondrosarcoma cells. The phosphatidylinositol 3-kinase (PI3K), Akt, and NF-κB pathways were activated by MIF treatment, and the MIF-induced expression of integrin and migration activity were inhibited by the specific inhibitors and mutant forms of PI3K, Akt, and NF-κB cascades. In addition, migration-prone sublines demonstrated that increased cell migration ability was correlated with increased expression of MIF and αvβ3 integrin. Taken together, our results indicate that MIF enhanced the migration of the chondrosarcoma cells by increasing αvβ3 integrin expression through the PI3K/Akt/NF-κB signal transduction pathway.     

Macrophage migration inhibitory factor-deficient mice are resistant to ovariectomy-induced bone loss

A link between macrophage migration inhibitory factor (MIF) and estrogen has recently emerged. We examined the involvement of MIF in osteoporotic changes in bone after ovariectomy (OVX), and revealed that MIF-deficient mice (MIF-KO) were completely protected from this phenomenon. The increase in osteoclast number per bone surface and serum IL-1β levels, which were observed in wild-type mice after OVX, did not occur in MIF KO. Our data suggest that MIF plays an important role in the pathogenesis of postmenopausal osteoporosis, and could be a novel target for the treatment of this disease.     

Dual regulation of macrophage migration inhibitory factor (MIF) expression in hypoxia by CREB and HIF-1

Macrophage migration inhibitory factor (MIF) is a well-described pro-inflammatory mediator that has also been implicated in the process of oncogenic transformation and tumor progression. However, despite the compelling evidence that MIF is overexpressed in, and contributes to, the pathology of inflammatory and malignant diseases the mechanisms that contribute to exaggerated expression of MIF have been poorly described. Here we show that hypoxia, and specifically HIF-1alpha, is a potent and rapid inducer of MIF expression. In addition, we demonstrate that hypoxia-induced MIF expression is dependent upon a HRE in the 5'UTR of the MIF gene but is further modulated by CREB expression. We propose a model where hypoxia-induced MIF expression is driven by HIF-1 but amplified by hypoxia-induced degradation of CREB. Given the importance of MIF in inflammatory and malignant diseases these data reveal a HIF-1-mediated pathway as a potential therapeutic target for suppression of MIF expression in hypoxic tissues.     

Pathogenic bacteria and TNF do not induce production of macrophage migration inhibitory factor (MIF) by human monocytes

Elevated serum macrophage migration inhibitory factor (MIF) is associated with severe sepsis, but it is not clear whether bacteria stimulate synthesis of MIF by blood leukocytes directly or via induction of TNF. Here we assess production of MIF mRNA and protein by blood leukocytes from healthy human subjects (n = 28) following exposure to bacteria commonly associated with sepsis (Escherichia coli and Streptococcus pneumoniae). Bacteria did not increase levels of MIF mRNA or secreted protein. CD14⁺ monocytes were the main cell type producing MIF before and after stimulation. Exposure of leukocytes to TNF did not induce MIF. Hence elevated levels of serum MIF observed in sepsis may not reflect MIF produced by blood leukocytes stimulated directly by bacteria or TNF.     

G to C transition at position −173 of MIF gene of the recipient is associated with reduced relapse rates after allogeneic stem cell transplantation

Pro-inflammatory and dendritic cell-activating properties of macrophage migration inhibitory factor (MIF) suggest a potentially important role for MIF in alloantigen-specific immune responses after allogeneic stem cell transplantation (allo-SCT). We tested whether MIF −173 G/C gene polymorphism of donor or patient had impacts on the outcomes after allo-SCT. Four hundred and fifty-four donor–patient pairs were genotyped and mortality, relapse, and development of complications were analyzed. Patient but not donor MIF −173*C allele was associated with improved overall survival (OS) (5 years: 60.8% versus 46.3%, p = 0.042) and disease free survival (DFS) (5 years: 55.4% versus 39.5%; p = 0.014) due to a reduction in relapse (day 2000: 22.8% versus 42.0% p = 0.006) but not due to decreased transplantation-related mortality (TRM) (p = 0.44). Multivariate analysis proved patient −173*C allele as an independent factor for reducing relapse after allo-SCT (p = 0.023). Subgroup analysis showed a clear MIF −173*C allele-related reduction in relapse for those patients who did not receive T cell depleted (TCD) SCT (p = 0.01) in contrast to patients receiving TCD SCT (p = 0.20). In summary, patient MIF −173*C allele may be linked to specific, yet unrevealed functions in tumor biology and graft versus leukemia and lymphoma effects and potentially presents a novel prognostic marker for patient-tailored counseling and therapy in allo-SCT.     

Selective binding interactions of deramciclane to the genetic variants of human α1-acid glycoprotein

Background

α₁-Acid glycoprotein (AGP) plays a decisive role in the serum protein binding of several drugs.Genetic variants of AGP have different ligand binding properties. The binding of deramciclane (DER), a chiral anxiolytic agent, has been studied on A and F1/S genetic variants of AGP.

Methods

The effects of DER and reference drugs on the binding of specific fluorescent and circular dichroism (CD) probes of AGP were determined. Dicumarol (DIC) binding was measured by CD and equilibrium dialysis.

Results

DER effectively displaced probes bound to variant A, while it was less effective at displacing probes bound to variant F1/S. DER increased the binding and inverted the induced CD spectrum of DIC in the solution of variant F1/S. This phenomenon could not be brought about by the enantiomer of DER.

Conclusion

DER has high-affinity binding (K_a ≥ 2×10⁶ M^-1) to variant A, while its binding to the variant F1/S is about thirty times weaker. During simultaneous binding of DER and DIC to variant F1/S a ternary complex having about four times higher affinity is formed, in which the opposite chiral conformation of DIC is favored.

General significance

The binding interactions found prove that AGP can simultaneously accommodate different ligand molecules. Even weakly bound ligands can provoke unexpected allosteric protein binding interactions.     

Analysis of MIF,FCGR2A and FCGR3A gene polymorphisms with susceptibility to pulmonary tuberculosis in Moroccan population

In order to investigate the influence of functional polymorphisms of macrophage migration inhibitory factor(MIF),Fcg receptors CD16A(FCGR3A) and CD32A(FCGR2A) genes on susceptibility to pulmonary tuberculosis(PTB) in the Moroccan population,we analyzed 123 patients with PTB and 154 healthy controls.The genotyping for MIF-173(G/C)(rs755622),FCGR2A-131H/R(rs1801274) and FCGR3A-158V/F(rs396991) was carried out using TaqMan SNP Genotyping Assay method.We found a statistically significant increase of the MIF-173...