Lack of macrophage migration inhibitory factor in mice does not affect hallmarks of the inflammatory/immune response during the first week after stroke

<p>Abstract</p> <p>Background</p> <p>Macrophage migration inhibitory factor (MIF) has been proposed to play a detrimental role in stroke. We recently showed that MIF promotes neuronal death and aggravates neurological deficits during the first week after experimental stroke, in mice. Since MIF regulates tissue inflammation, we studied the putative role of MIF in post-stroke inflammation.</p> <p>Methods</p> <p>We subjected C57BL/6 mice, <it>Mif</it>^-/-(MIF-KO) or <it>Mif</it>^+/+(WT), to a transient occlusion of the right middle cerebral artery (tMCAo) or sham-surgery. We studied MIF expression, GFAP expression and the number of CD74-positive cells in the ischemic brain hemisphere 7 days after tMCAo using primarily immunohistochemistry. We determined IFN-γ, IL-2, IL-4, IL-5, IL-10, IL-12, KC/CXCL-1 and TNF-α protein levels in the brain (48 h after surgery) and serum (48 h and 7 days after surgery) by a multiplex immunoassay.</p> <p>Results</p> <p>We observed that MIF accumulates in neurons and astrocytes of the peri-infarct region, as well as in microglia/macrophages of the infarct core up to 7 days after stroke. Among the inflammatory mediators analyzed, we found a significant increase in cerebral IL-12 and KC levels after tMCAo, in comparison to sham-surgery. Importantly, the deletion of <it>Mif </it>did not significantly affect the levels of the cytokines evaluated, in the brain or serum. Moreover, the spleen weight 48 h and 7 days subsequent to tMCAo was similar in WT and MIF-KO mice. Finally, the extent of GFAP immunoreactivity and the number of MIF receptor (CD74)-positive cells within the ischemic brain hemisphere did not differ significantly between WT and MIF-KO mice subjected to tMCAo.</p> <p>Conclusions</p> <p>We conclude that MIF does not affect major components of the inflammatory/immune response during the first week after experimental stroke. Based on present and previous evidence, we propose that the deleterious MIF-mediated effects in stroke depend primarily on an intraneuronal and/or interneuronal action.</p

Aging-associated Alteration in the Cardiac MIF-AMPK Cascade in Response to Ischemic Stress

An important role for a macrophage migration inhibitory factor (MIF)-AMP-activated protein kinase (AMPK) signaling pathway in ameliorating myocardial damage following ischemia/reperfusion has been described. An aging-associated reduction in AMPK activity may be associated with a decline in the ability of cardiac cells to activate the MIF-AMPK cascade, thereby resulting in reduced tolerance to ischemic insults. To test this hypothesis, _in vivo_ regional ischemia was induced by occlusion of the left anterior descending (LAD) coronary artery in young (4-6 months) and aged (24-26 months) mice. The ischemic AMPK activation response was impaired in aged hearts compared to young ones (p&#x3c;0.01). Notably, cardiac MIF expression in aged hearts was lower than in young hearts (p&#x3c;0.01). Dual staining data clearly demonstrated larger infarct size in aged hearts following ischemia and reperfusion compared to young hearts (p&#x3c;0.05). Ischemia-induced AMPK activation in MIF knock out (MIF KO) hearts was blunted, leading to greater contractile dysfunction of MIF KO cardiomyocytes during hypoxia than that of wild type (WT) cardiomyocytes. Finally exogenous recombinant MIF significantly reversed the contractile dysfunction of aged cardiomyocytes in response to hypoxia. We conclude that an aging-associated reduction in ischemic AMPK activation contributes to ischemic intolerance in aged hearts

Increased fructose 2,6-bisphosphate in peripheral blood mononuclear cells of patients with diabetes

Fructose 2,6-bisphosphate (F2,6BP) is a powerful allosteric activator of 6-phosphofructo-1-kinase, which is the rate-limiting enzyme for glycolysis. Mitogenic stimulation of lymphocytes is related to an enhanced rate of glucose utilization and F2,6BP mediated activation of glycolysis. To determine the effect of hyperglycemia on intracellular glycolysis of lymphocytes, we measured intracellular F2,6BP content in peripheral blood mononuclear cells obtained from patients with diabetes and normal subjects. A total of 62 subjects participated in the present study. Venous blood samples were collected and peripheral blood mononuclear cells were separated by Ficoll gradients. Intracellular F2,6BP levels in peripheral blood mononuclear cells from normal control subjects were significantly lower than age-matched diabetic subjects. We observed a significant positive correlation between intracellular F2,6BP levels and long term glycemic control, as assessed by HbA1c. These data suggest that hyperglycemia increases intracellular F2,6BP in immune cells. These findings may help to clarify the impaired function in immune cells in patients with diabetes

MIF contributes to Trypanosoma brucei associated immunopathogenicity development

African trypanosomiasis is a chronic debilitating disease affecting the health and economic well-being of many people in developing countries. The pathogenicity associated with this disease involves a persistent inflammatory response, whereby M1-type myeloid cells, including Ly6C(high) inflammatory monocytes, are centrally implicated. A comparative gene analysis between trypanosusceptible and trypanotolerant animals identified MIF (macrophage migrating inhibitory factor) as an important pathogenic candidate molecule. Using MIF-deficient mice and anti-MIF antibody treated mice, we show that MIF mediates the pathogenic inflammatory immune response and increases the recruitment of inflammatory monocytes and neutrophils to contribute to liver injury in Trypanosoma brucei infected mice. Moreover, neutrophil-derived MIF contributed more significantly than monocyte-derived MIF to increased pathogenic liver TNF production and liver injury during trypanosome infection. MIF deficient animals also featured limited anemia, coinciding with increased iron bio-availability, improved erythropoiesis and reduced RBC clearance during the chronic phase of infection. Our data suggest that MIF promotes the most prominent pathological features of experimental trypanosome infections (i.e. anemia and liver injury), and prompt considering MIF as a novel target for treatment of trypanosomiasis-associated immunopathogenicity

Influence of glass component for sintering process of LTCC composite materials

In this work two BaO-ZnO-B[2]O[3]-SiO[2] glass-forming systems with different components content and similar properties were compared for using in LTCC materials. Glass-ceramics sintering characteristics and their phase composition were researched by hydrostatic weighing. Causes of the differences in properties of the composites based on two glasses were identified

Ostertagia ostertagi macrophage migration inhibitory factor is present in all developmental stages and may cross-regulate host functions through interaction with the host receptor

Macrophage migration inhibitory factor (MIF) of Ostertagia ostertagi, an abomasal parasite of cattle, was characterised in the present study. Phylogenetic analysis identified at least three O. ostertagi MIFs (Oos- MIFs), each encoded by a distinct transcript: Oos-MIF-1.1, Oos-MIF-1.2 and Oos-MIF-2. Oos-MIF-2 is only distantly related to Oos-MIF-1s, but has higher sequence similarity with the Caenorhabditis elegans MIF2. Oos-MIF-1.1 and Oos-MIF-1.2 are similar (93%) and thus collectively referred to as Oos-MIF-1 when characterised with immunoassays. Recombinant Oos-MIF-1.1 (rOos-MIF-1.1) is catalytically active as a tautomerase. A mutation (rOos-MIF-1.1P1G) or duplication of Pro1 residue (rOos-MIF-1.1P1+P) resulted in reduced oligomerisation and loss of tautomerase activity. The tautomerase activity of rOos-MIF-1.1 was only partially inhibited by ISO-1 but was abrogated by a rOos-MIF-1.1-specific antibody. Oos-MIF- 1 was detected in all developmental stages of O. ostertagi, with higher levels in the adult stage; it was also detected in adult worm excretory/secretory product. Oos-MIF-1 was localised to the hypodermis/muscle, reproductive tract and intestine, but not to the cuticle. rOos-MIF-1.1, but not rOos-MIF-1.1P1G, was able to specifically bind to human CD74, a MIF cell surface receptor, with an affinity comparable with human MIF. Immunostaining indicated that macrophages were able to internalise rOos-MIF-1.1, further supporting receptor-mediated transportation. Herein we also show that rOos-MIF-1.1 inhibited migration of bovine macrophages and restored glucocorticoid-suppressed, lipopolysaccharide-induced TNF-a and IL-8 in human and/or bovine macrophages. Given its dual role in self-regulation and molecular mimicry, this secreted parasite protein warrants investigation as a vaccine candidate against O. ostertagi infections in cattle

Drug Repositioning and Pharmacophore Identification in the Discovery of Hookworm MIF Inhibitors

SummaryThe screening of bioactive compound libraries can be an effective approach for repositioning FDA-approved drugs or discovering new pharmacophores. Hookworms are blood-feeding, intestinal nematode parasites that infect up to 600 million people worldwide. Vaccination with recombinant Ancylostoma ceylanicum macrophage migration inhibitory factor (rAceMIF) provided partial protection from disease, thus establishing a “proof-of-concept” for targeting AceMIF to prevent or treat infection. A high-throughput screen (HTS) against rAceMIF identified six AceMIF-specific inhibitors. A nonsteroidal anti-inflammatory drug (NSAID), sodium meclofenamate, could be tested in an animal model to assess the therapeutic efficacy in treating hookworm disease. Furosemide, an FDA-approved diuretic, exhibited submicromolar inhibition of rAceMIF tautomerase activity. Structure-activity relationships of a pharmacophore based on furosemide included one analog that binds similarly to the active site, yet does not inhibit the Na-K-Cl symporter (NKCC1) responsible for diuretic activity

Macrophage Migration Inhibitory Factor Mediates Protease-Activated Receptor 4-Induced Bladder Pain Through Urothelial High Mobility Group Box 1

Macrophage migration inhibitory factor (MIF) mediates pain although the mechanisms are not well understood. Urothelial activation of protease activated receptor 4 (PAR4) results in urothelial MIF release, urothelial high mobility group box 1 (HMGB1) release and bladder pain in mice without bladder inflammation. All three effects are prevented by MIF inhibition while intravesical disulfide HMGB1 alone can induce bladder pain. This study utilizes genetic MIF deletion to determine whether MIF mediates PAR4-induced bladder pain and is upstream of HMGB1-induced bladder pain. Wild type (C57/BL6) and MIF knockout (KO) mice were treated with intravesical PAR4 activating peptide or disulfide HMGB1 and tested for abdominal mechanical hypersensitivity at baseline (before treatment) and 24 h after injection. Micturition parameters and bladder histology were examined after behavioral test. Real-time PCR and western blotting measured HMGB1 mRNA and protein levels in the bladders of naïve wild type and MIF KO mice, while immunofluorescence measured HMGB1 protein levels in the urothelium of both strains. Intravesical PAR4 activation resulted in abdominal mechanical hypersensitivity in wild-type mice but not MIF KO mice. Intravesical disulfide HMGB1 induced abdominal mechanical hypersensitivity in both strains. Neither treatment resulted in significant changes in micturition or bladder histology in either strain. HMGB1 mRNA and protein levels were higher in MIF KO mouse bladders and the urothelium of MIF KO bladder had greater immunostaining than the wild-type strain. MIF is a pivotal molecule mediating PAR4-induced bladder pain and regulating urothelial HMGB1 production and release to elicit bladder pain

Fibrocytes in health and disease

Fibrocytes, a group of bone marrow-derived mesenchymal progenitor cells, were first described in 1994 as fibroblast-like, peripheral blood cells that migrate to regions of tissue injury. These cells are unique in their expression of extracellular matrix proteins concomitantly with markers of hematopoietic and monocyte lineage. The involvement of fibrocytes and the specific role they play in the process of wound repair has been a focus of study since their initial description. Fibrocytes contribute to the healing repertoire via several mechanisms; they produce a combination of cytokines, chemokines, and growth factors to create a milieu favorable for repair to occur; they serve as antigen presenting cells (APCs); they contribute to wound closure; and, they promote angiogenesis. Furthermore, regulatory pathways involving serum amyloid P, leukocyte-specific protein 1, and adenosine A2A receptors have emphasized the significant role that fibrocytes have in wound healing and fibrosis. The therapeutic targeting of fibrocytes holds promise for the augmentation of wound repair and the treatment of different fibrosing disorders