Macrophage migration inhibitory factor (MIF) is a multifunctional protein that exhibits an intrinsic thiol protein oxidoreductase activity and proinflammatory activities. In the present study to examine intracellular MIF redox function, exposure of MIF-deficient cardiac fibroblasts to oxidizing conditions resulted in a 2.3-fold increase (p < 0.001) in intracellular ROS that could be significantly reduced by adenoviral-mediated reexpression of recombinant MIF. In an animal model of myocardial injury by ischemia/reperfusion (I/R), MIF-deficient hearts exhibited higher levels of oxidative stress than did wild-type hearts, as measured by significantly higher oxidized glutathione levels (decreased GSH/GSSG ratio), increased protein oxidation, reduced aconitase activity, and increased mitochondrial injury (increased cytochrome c release). The increased myocardial oxidative stress after I/R was reflected by larger infarct size (INF) in MIF-deficient hearts versus wild-type (WT) hearts (21 ± 6% vs. 8 ± 3% INF/LV; p < 0.05). In vivo hemodynamic measurements showed that left ventricular (LV) contractile function of MIF-deficient hearts subjected to 15-min ischemia failed to recover during reperfusion compared with WT hearts (LV developed pressure and ± dP/dt; p = 0.02). These data represent the first in vivo evidence in support of a cardioprotective role of MIF in the postischemic heart by reducing oxidative stress.
MIF-induced neutrophil accumulation in the alveolar space results from interaction with CD74 expressed on the surface of alveolar macrophage cells. This interaction induces p44/p42 MAPK activation and chemokine release. The data suggest that MIF and its receptor, CD74, may be useful targets to reduce neutrophilic lung inflammation, and acute lung injury.
α‐Amino acids imidazolium salt smoothly reacted with diphenylcarbonate to afford the corresponding urethanes. The urethanes were activated by adding carboxylic acid to undergo selective cyclization, leading to successful development of a new phosgene‐free process for synthesizing α‐amino acid N‐carboxyanhydrides (NCAs).
A new convenient access to N‐carboxyanhydride (NCA) monomers has been achieved based on the utilization of bisarylcarbonates as a carbonyl source, which are activated by electron‐withdrawing substituents on their aryl groups such as fluorine atom and nitro group. [Color figure can be viewed in the online issue, which is available at www.interscience.wiley.com.]
Macrophage migration inhibitory factor (MIF) functions as a proinflammatory cytokine when secreted from the cell, but it also exhibits antioxidant properties by virtue of its intrinsic oxidoreductase activity. Since increased production of ROS is implicated in the development of left ventricular hypertrophy, we hypothesized that the redox activity of MIF protects the myocardium when exposed to hemodynamic stress. In a mouse model of myocardial hypertrophy induced by transverse aortic coarctation (TAC) for 10 days, we showed that growth of the MIF-deficient heart was significantly greater by 32% compared with wild-type (WT) TAC hearts and that fibrosis was increased by fourfold (2.62 Ϯ 0.2% vs. 0.6 Ϯ 0.1%). Circulating MIF was increased in TAC animals, and expression of MIF receptor, CD74, was increased in the hypertrophic myocardium. Gene expression analysis showed a 10-fold increase (P Ͻ 0.01) in ROS-generating mitochondrial NADPH oxidase and 2-to 3-fold reductions (P Ͻ 0.01) in mitochondrial SOD2 and mitochondrial aconitase activities, indicating enhanced oxidative injury in the hypertrophied MIF-deficient ventricle. Hypertrophic signaling pathways showed that phosphorylation of cytosolic glycogen synthase kinase-3␣ was greater (P Ͻ 0.05) at baseline in MIF-deficient hearts than in WT hearts and remained elevated after 10-day TAC. In the hemodynamically stressed MIFdeficient heart, nuclear p21 CIP1 increased sevenfold (P Ͻ 0.01), and the cytosolic increase of phospho-p21 CIP1 was significantly greater than in WT TAC hearts. We conclude that MIF antagonizes myocardial hypertrophy and fibrosis in response to hemodynamic stress by maintaining a redox homeostatic phenotype and attenuating stressinduced activation of hypertrophic signaling pathways.
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