krn-7000 and Reperfusion-Injury

Topics: Animals; Antigens, CD1d; Cells, Cultured; Coculture Techniques; Galactosylceramides; Interferon-gamma; Interleukin-4; Liver; Liver Regeneration; Lymphocyte Activation; Macrophage Activation; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; Reperfusion Injury

Gut ischemia reperfusion (I/R) injury is a life-threatening condition. The immune response plays an important role in I/R-induced organ injury. Alpha-galactosylceramide (α-GalCer) is a potent natural killer T (NKT) cell stimulator. Activation of NKT cells by α-GalCer has been shown to reduce I/R-induced injury in the liver and heart. However, whether α-GalCer has any protective effects on gut I/R-induced organ injury remained unknown. The aim of this study was to test the hypothesis that α-GalCer attenuates gut I/R-induced local and remote organ injury through modulating immune responses.. Gut ischemia was induced by placing a microvascular clip across the superior mesenteric artery for 30 min in male adult mice. After removing the clip, α-GalCer (2 µg/mouse) or normal saline containing 0.5% Tween 20 (Vehicle) was administered intraperitoneally. Blood, gut, lung and mesenteric lymph node (MLN) samples were collected 4 h after reperfusion to detect bacterial translocation, tight junction protein, tissue damage, edema, apoptosis, IL-4, IL-10, IFN-γ and TNF-α levels.. α-GalCer significantly reduced bacterial translocation to the MLN, restored tight junction protein and attenuated gut and lung injury after gut I/R. α-GalCer markedly stimulated the production of IL-4, IL-10 and IFN-γ, but had no obvious effects on TNF-α production in gut I/R mice. Pretreatment with anti-CD1d, IL-4 or IL-10, but not IFN-γ blocking antibodies abolished the protective effects of α-GalCer in gut I/R.. α-GalCer treatment improved gut barrier function and attenuated gut and lung injury after gut I/R. The beneficial effects of α-GalCer in gut I/R were NKT cell dependent and mediated through upregulation of IL-4 and IL-10. Thus, activation of NKT cells by α-GalCer may serve as a novel option in the treatment of gut I/R injury.

Topics: Animals; Cytotoxicity, Immunologic; Edema; Galactosylceramides; Interferon-gamma; Interleukin-10; Interleukin-4; Killer Cells, Natural; Ligands; Lung; Lymph Nodes; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Natural Killer T-Cells; Protective Agents; Reperfusion Injury; Tumor Necrosis Factor-alpha; Up-Regulation

Invariant natural killer T (iNKT) cells orchestrate tissue inflammation via regulating various cytokine productions. However the role of iNKT cells has not been determined in myocardial ischemia/reperfusion (I/R) injury. The purpose of this study was to examine whether the activation of iNKT cells by α-galactosylceramide (α-GC), which specifically activates iNKT cells, could affect myocardial I/R injury. I/R or sham operation was performed in male C57BL/6J mice. I/R mice received the injection of either αGC (I/R+αGC, n=48) or vehicle (I/R+vehicle, n=49) 30 min before reperfusion. After 24h, infarct size/area at risk was smaller in I/R+αGC than in I/R+vehicle (37.8 ± 2.7% vs. 47.1 ± 2.5%, P<0.05), with no significant changes in area at risk. The numbers of infiltrating myeloperoxidase- and CD3-positive cells were lower in I/R+αGC. Apoptosis evaluated by TUNEL staining and caspase-3 protein was also attenuated in I/R+αGC. Myocardial gene expression of tumor necrosis factor-α and interleukin (IL)-1β in I/R+αGC was lower to 46% and 80% of that in I/R+vehicle, respectively, whereas IL-10, IL-4, and interferon (IFN)-γ were higher in I/R+αGC than I/R+vehicle by 2.0, 4.1, and 9.6 folds, respectively. The administration of anti-IL-10 receptor antibody into I/R+αGC abolished the protective effects of αGC on I/R injury (infarct size/area at risk: 53.1 ± 5.2% vs. 37.4 ± 3.5%, P<0.05). In contrast, anti-IL-4 and anti-IFN-γ antibodies did not exert such effects. In conclusion, activated iNKT cells by αGC play a protective role against myocardial I/R injury through the enhanced expression of IL-10. Therapies designed to activate iNKT cells might be beneficial to protect the heart from I/R injury.

Topics: Animals; Cytokines; Galactosylceramides; Interleukin-10; Interleukin-4; Male; Mice; Mice, Inbred C57BL; Myocardial Ischemia; Natural Killer T-Cells; Reperfusion Injury

Hepatic preconditioning has emerged as a promising strategy of activating natural pathways to augment tolerance to liver ischemia-reperfusion (IR) injury. Liver-resident natural killer T (NKT) cells play an important role in modulating the local immune and inflammatory responses. This work was aimed to investigate whether preactivation of NKT cells could provide a beneficial "preconditioning" effect to ameliorate the subsequent hepatic IR injury. To selectively activate NKT cells, C57BL/6 mice were treated intraperitoneally with the glycolipid antigen alpha-galactosylceramide (alpha-GalCer) 1 h prior to hepatic ischemia. Significantly reduced liver IR injury was observed in mice pretreated with alpha- GalCer, and this protective effect was specifically abrogated by a CD1d blocking antibody. Serum TNF-alpha, IFN-gamma, and IL-13 levels were markedly increased shortly after alpha-GalCer injection. Pretreatment with a neutralizing antibody against TNF-alpha or IFN-gamma did not influence the protective effect of alpha-GalCer preconditioning, whereas preadministration of an IL-13 neutralizing antibody completely abolished the effect. Treatment with alpha-GalCer also led to an increased expression of adenosine A2A receptor (A2AR) in the liver, and blockade of A2AR by SH58261 diminished alpha-GalCer pretreatment-mediated attenuation of liver IR injury. In contrast, administration of the selective A2AR agonist CGS21680 reversed the counteracting effect of the IL-13 neutralizing antibody on alpha-GalCer preconditioning. Additionally, alpha-GalCer pretreatment was associated with a decreased neutrophil accumulation in the ischemic liver. These findings provide the first evidence that hepatic preconditioning by preactivation of NKT cells with alpha-GalCer protects the liver from IR injury via an IL-13 and adenosine A2AR-dependent mechanism.

Topics: Animals; Disease Models, Animal; Galactosylceramides; Injections, Intraperitoneal; Interferon-gamma; Interleukin-13; Ischemia; Liver; Lymphocyte Activation; Male; Mice; Mice, Inbred C57BL; Natural Killer T-Cells; Neutrophil Infiltration; Receptor, Adenosine A2A; Reperfusion Injury; Signal Transduction; Time Factors; Tumor Necrosis Factor-alpha