Protective role of NF-kappaB in liver cold ischemia/reperfusion injury: effects of IkappaB gene therapy

Amentoflavone ameliorates cold stress-induced inflammation in lung by suppression of C3/BCR/NF-κB pathways

Background

Cold stress, which may lead to local and systemic injury, is reported to be related to the immune system, especially the complement system. At present, the lack of effective treatment is a critical issue. Amentoflavone (AF), which can inhibit cold stress-induced inflammation in lung by multiple mechanisms, is the main therapeutic ingredient in plants of the genus Selaginella.

Results

In the current study, we found that cold could induce lung inflammation related to the complement system and its downstream pathways. AF treatment significantly inhibited lung inflammation from cold exposure. We presented evidence that AF can bind to complement component 3 (C3) to regulate inflammation-related pathways involving Lck/Yes novel tyrosine kinase (Lyn), protein kinase B (Akt), nuclear factor-κB (NF-κB) and immune factors. Moreover, 30 mg/kg of AF caused significantly greater improvement than 15 mg/kg in reducing the level of C3 in lung tissue.

Conclusions

AF can protect lung tissue from cold exposure. The protective effect may be achieved by inhibition of C3 and negative regulation of the B cell receptor (BCR)/NF-κB signaling pathways and high mobility group box 1 (HMGB1), which ultimately ameliorates the inflammatory response.

The Effects of Infliximab on Laminin, NFκB, and Anti-TNF Expression through Its Effect on Ischemic Liver Tissue

The aim of this study was to investigate the possible protective effects of infliximab on expression of laminin, anti-TNF, and NFκB in the rat hepatic cells after ischemia/reperfusion (I/R). A total of 30 male Wistar albino rats were divided into three groups: Control (C), sham I/R (ISC), and I/R+ infliximab (ISC inf); each group comprised 10 animals. C group animals underwent laparotomy without I/R injury. In ISC groups after undergoing laparotomy, 1 hour of superior mesenteric artery ligation was done, which was followed by 1 hour of reperfusion. In the ISC inf group, 3 days before I/R, infliximab (3 mg/kg) was administered intravenously. All animals were killed at the end of reperfusion and hepatic tissue samples were obtained for histopathological and histochemical investigations in all groups. Laminin, anti-TNF, and NFκB immunoreactivity were performed for all groups. ISC caused severe histopathological injury including mucosal erosions, inflammatory cell infiltration, necrosis, hemorrhage, and villous congestion. Infliximab treatment significantly attenuated the severity of intestinal I/R injury and it is shown by laminin, anti-TNF, and NFκB immunoreactivity. Because of its anti-inflammatory and antioxidant effects, infliximab pretreatment may have protective effects on hepatic cells in the experimental intestinal I/R model of rats.

Delayed ischemic preconditioning protects against liver ischemia-reperfusion injury in vivo

OBJECTIVES

Ischemic preconditioning (IP) affords resistance to liver ischemia-reperfusion (IR) injury, providing an early phase of protection. Development of delayed IP against IR injury was assessed using partial IR in rat liver.

METHODS

The IP manuver (10 minutes of ischemia and up to 72 hours of reperfusion) was induced before 1 hour of ischemia and 20 hours of reperfusion. At the end of the reperfusion period, blood and liver samples were analyzed for serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), haptoglobin and tumor necrosis factor-alpha (TNF-alpha) levels, hepatic histology, protein carbonyl and glutathione (GSH) contents as well as nuclear factor-kappaB (NF-kappaB), and activating protein-1 (AP-1) DNA binding.

RESULTS

The IP manuver significantly increased protein carbonyl/GSH ratios (275%), serum ALT (42%), and AST (58%); these changes normalized after 12 hours. Serum AST, ALT, and LDH levels were significantly increased by IR (4-, 5.6-, and 7.0-fold, respectively), with significant changes in liver histology, protein carbonyl/GSH ratio (481% enhancement), and serum TNF-alpha (6.1-fold increase). Delayed IP in IR animals reduced serum AST (66%), ALT (57%), and LDH (90%) and liver GSH depletion (89%), with normalization of protein carbonyl content, serum TNF-alpha levels, and liver histology. Enhanced AP-1/NF-kappaB DNA binding ratios and diminished haptoglobin expression induced by IR were normalized by IP.

CONCLUSION

These data support that delayed IP suppresses IR-induced liver injury, oxidative stress, and TNF-alpha response, which coincide with recovery of IR-altered signaling functions represented by normal AP-1/NF-kappaB DNA binding ratios and acute phase responses.

Gene therapy targeting nuclear factor-kappaB: towards clinical application in inflammatory diseases and cancer

Nuclear factor (NF)-κB is regarded as one of the most important transcription factors and plays an essential role in the transcriptional activation of pro-inflammatory cytokines, cell proliferation and survival. NF-κB can be activated via two distinct NF-κB signal transduction pathways, the so-called canonical and non-canonical pathways, and has been demonstrated to play a key role in a wide range of inflammatory diseases and various types of cancer. Much effort has been put in strategies to inhibit NF-κB activation, for example by the development of pharmacological compounds that selectively inhibit NF-κB activity and therefore would be beneficial for immunotherapy of transplantation, autoimmune and allergic diseases, as well as an adjuvant approach in patients treated with chemotherapy for cancer. Gene therapy targeting NF-κB is a promising new strategy with the potential of long-term effects and has been explored in a wide variety of diseases, ranging from cancer to transplantation medicine and autoimmune diseases. In this review we discuss recent progress made in the development of NF-κB targeted gene therapy and the evolution towards clinical application.

Ex vivo transfer of nuclear factor-kappaB decoy ameliorates hepatic cold ischemia/reperfusion injury

Cold ischemia/reperfusion injury of the hepatic graft has been attributed to the release of various inflammatory cytokines. Specific inhibition of these cytokines may improve viability of the hepatic graft upon reperfusion. Herein we have assessed the efficacy of cis element decoy against nuclear factor-kappaB binding site delivery to the hepatic tissue in a rodent liver transplantation model. At 8 hours after reperfusion of the liver, significant reduction was noted in the livers treated with decoy in the release of cytosolic enzymes from the hepatocytes and in serum tumor necrosis factor alpha (P < .05). The neutrophilic infiltration into the hepatic grafts was significantly suppressed in the livers treated with decoy oligodeoxynucleotides (ODNs). Decoy ODNs against nuclear factor-kappaB binding site delivery improved the viability of the hepatic graft against cold ischemia/reperfusion injury in the rodent liver transplantation model.

Effects of Diethyldithiocarbamate (DETC) on Liver Injury Induced by Ischemia-Reperfusion in Rats

PURPOSE

In organ transplantation, ischemia-reperfusion injury (I/R) is a constant occurrence. Dithiocarbamates, a class of antioxidants, have been reported to inhibit nuclear factor-kappaB (NF-kappaB), a critical transcription factor in the intracellular inflammatory cascade. We studied the effects of diethyldithiocarbamate (DETC) on liver injury induced by I/R.

MATERIALS AND METHODS

Male Wistar rats were pretreated with DETC (100 mg/kg IV) 10 minutes before hepatic ischemia, which was followed by 2 hours reperfusion, or 10 minutes prior to the reperfusion. Blood samples were obtained at the end of the reperfusion period to determine the biochemical markers of liver injury. Results were compared using the one-way analysis of variance (ANOVA), followed by the Bonferroni posttest, and presented as mean values +/- SEM.

RESULTS

I/R produced significant increases in aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), and gamma-glutamyl transferase (gamma-GT) serum levels compared with sham-operated rats. Administration of DETC prior to the onset of reperfusion significantly reduced the liver injury. However, DETC administered before the ischemic period failed to protect the liver from an I/R injury.

CONCLUSION

DETC, administered just before the reperfusion period, resulted in a significant decrease in the I/R injury to the liver, an observation that may have therapeutic implications.

In vivo suppressive effect of nuclear factor-κB inhibitor on neutrophilic inflammation of grafts after orthotopic liver transplantation in rats

AIM: To investigate the effect of pyrrolidine dithiocarbamate (PDTC), a novel nuclear factor-κB (NF-κB) inhibitor, on expression of multiple inflammatory mediators and neutrophilic inflammation of cold preserved grafts after rat liver transplantation and its significance.

METHODS: Orthotopic liver transplantation (OLT) was performed after 24 h of cold storage using University of Wisconsin solution with varied concentrations of PDTC. We determined the time course of NF-κB activation and expression of multiple inflammatory signals, such as tumor necrosis factor-α (TNF-α), cytokine-inducible neutrophil chemoattractant (CINC), and intercellular adhesion molecule-1 (ICAM-1) by ELISA methods. Serum alanine aminotransferase (ALT), intrahepatic myeloperoxidase (MPO)/WBC (a measure of neutrophil accumulation) and Mac-1 expression (a measure of circulating neutrophil activity) were also evaluated.

RESULTS: PDTC decreased NF-κB activation induced by prolonged cold preservation in a dose dependent manner (from 20 mmol/L to 60 mmol/L), diminished TNF-α, CINC, ICAM-1 proteins in the grafts, and reduced the expression of increases in plasma TNF-α levels induced by prolonged cold preservation. Neutrophilic inflammation of the graft was significantly suppressed after preservation with PDTC (P < 0.05). The total neutrophil accumulation in PDTC (40 mmol/L) group (7.04 ± 0.97) was markedly reduced compared to control group (14.07 ± 1.31) (P < 0.05). Mac-1 expression was significantly reduced in PDTC (40 mmol/L) group (181 ± 11.3%) compared with the control group (281 ± 13.2%) (P < 0.05) at 6 h after reperfusion. Furthermore, PDTC inhibited the increased serum ALT levels after liver transplantation.

CONCLUSION: PDTC can inhibit B NF-κB activation and expression of the inflammatory mediators, which are associated with improved graft viability via inhibiting intrahepatic neutrophilic inflammation. Our study suggests that a therapeutic strategy directed at inhibition of NF-κB activation in the transplanted liver might be effective in reducing intrahepatic neutrophilic inflammation, and would be beneficial to cold preserved grafts.

The hydroxyl radical scavenger MCI-186 protects the liver from experimental cold ischaemia-reperfusion injury

BACKGROUND

Oxidative stress contributes to hepatic ischaemia-reperfusion (IR) injury in a biphasic pattern. In addition to direct cytotoxic effects, oxidative stress also initiates the signal transduction processes that promote second-phase liver injury. The present study investigated the effects of the hydroxyl radical scavenger MCI-186 on the biphasic process of hepatic cold IR injury.

METHODS

After cold preservation for 16 h, rat livers were reperfused on an isolated liver perfusion system for 120 min with oxygenated Krebs-Henseleit bicarbonate buffer. Perfusate samples were obtained serially, and portal flow rates were also recorded. To determine whether MCI-186 affected cytokine levels that control the second-phase injury, levels of interleukin (IL) 10 and tumour necrosis factor (TNF) alpha were measured in the perfusate.

RESULTS

Addition of MCI-186 1 mg/l into the perfusate significantly improved portal flow (P<0.050), hepatic enzyme release into the perfusate (P=0.038), total bile production (P=0.029) and malondialdehyde concentration (P=0.038). Furthermore, treatment with MCI-186 led to a substantial increase in IL-10 release (P=0.032). TNF-alpha levels were not affected.

CONCLUSIONS

MCI-186, an agent ready for clinical use, appears to have direct and indirect protective effects against hepatic cold IR injury.

Kupffer cells play an important role in the cytokine production and activation of nuclear factors of liver grafts from non-heart-beating donors

In the non-heart-beating donor (NHBD) deterioration of microcirculation of the liver graft is strongly associated with secretion of cytokines and eicosanoids. In this study we investigated the excretion of cytokines, eicosanoids, and DNA binding activity of transcription factors in the grafts from NHBD and evaluated the effects of the elimination of Kupffer cells on them. The purpose of this study was to clarify the impact of Kupffer cells on transcription factor activity and the that of cytokine and eicosanoid production on reperfusion injury of liver grafts from NHBD. Wistar rats were allocated to four groups: (a). control group: livers were extracted under heart-beating conditions and perfused without cold storage, (b). heart beating (HB) group: livers extracted under heart-beating conditions were perfused after 6 h of cold storage, (c). non-heart-beating (NHB) group: livers extracted after cardiac arrest were perfused after cold storage, (d). Kupffer cell eliminated (KE) group: liposome-encapsulated dichloromethylene diphosphonate was intravenously administered to eliminate Kupffer cells before extraction, and the liver was perfused after cold storage. Cytokines and eicosanoids in perfusate were measured. DNA binding activity of nuclear factor kappa B, activating protein 1, and nuclear factor-interleukin 6 of tissue were investigated. Concentrations of interleukin 1 beta and thromboxane B(2) in the perfusate were significantly higher in NHB group, but they were completely suppressed in the KE group. A rise in binding activity of nuclear factor kappa B and activating protein 1 was not observed during cold storage in any groups, but these activities did increase remarkably after reperfusion. Significant buildup of those activities were recognized in the NHB group, and this phenomenon was inhibited in the KE group. The histological structures of the sinusoid in the KE group were well maintained, as with those of the control group. These results indicate that cytokines, eicosanoids, and the DNA binding activity of the transcripton factor are strongly associated with reperfusion injury, and Kupffer cells play an important role in this mechanism in grafts from NHBDs.