Hemorrhage-induced interleukin-1 receptor pathway in lung is suppressed by 3,5-bis(2-fluorobenzylidene)-4-piperidone in a rat model of hypovolemic shock

Evaluation of anti-inflammatory diphenyldihaloketone EF24 in transient ischemic stroke model

OBJECTIVES

Revascularization is necessary in patients with ischemic stroke, however it does not address inflammation that contribute to reperfusion injury and the early growth of ischemic core. We investigated EF24, an anti-inflammatory agent, in a stroke model.

METHODS

Ischemic stroke was induced in mice by occluding middle cerebral artery for 1 h followed by reperfusion. EF24 was given either 10 min post-reperfusion (EF24_Post) or 10 min before occlusion (prophylactic, EF24_Pro). Survival, ipsilateral uptake of radioactive infarct marker ¹⁸F-fluoroglucaric acid (FGA), inflammatory cytokines, and tetrazolium chloride (TTC) staining were assessed.

RESULTS

Survival was increased in both EF24-treated groups compared to the stroke+vehicle group. Ipsilateral ¹⁸F-FGA uptake increased 2.6-fold in stroke+vehicle group compared to sham group (p < 0.05); the uptake in EF24-treated groups and sham group was not significantly different. TTC-staining also showed reduction in infarct size by EF24 treatment. Plasma IL-6, TNF-α, and corticosterone did not show significant changes among groups. However, ipsilateral tissue in stroke+vehicle mice showed increased IL-6 (>90-fold) and TNF-α (3-fold); the tissue IL-6 and TNF-α were significantly reduced in stroke+EF24_Pro and stroke+EF24_Post groups. ¹⁸F-FGA uptake significantly correlated with tissue IL-6 levels.

CONCLUSIONS

EF24 controls infarct growth and suppresses tissue inflammation in ischemic stroke, which can be monitored by ¹⁸F-FGA uptake.

Anti-inflammatory mediators ST2 and SIGIRR are induced by diphenyldifluoroketone EF24 in lipopolysaccharide-stimulated dendritic cells

The objective of this study was to investigate the effect of EF24, an NF-κB-inhibitor, on the expression of negative regulators in IL-1R pathway, namely ST2 and SIGIRR. Murine JAWS II dendritic cells (DC) were challenged with lipopolysaccharide (LPS, 100 ng/ml) for 4 h, followed by treatment with 10 μM EF24 for 1 h. ST2 and SIGIRR expression was monitored by qRT-PCR and immunoblotting. ST2L and MyD88 interaction was studied by co-immunoprecipitation, and IL-33, a ST2L ligand, was assayed by ELISA. Activation of transcription factor SP1 was examined by confocal microscopy, immunoblotting, and EMSA. The effect of EF24 on accumulation of ubiquitinated proteins in DCs and proteolysis of fluorogenic peptides by purified proteasome was studied. We found that EF24 upregulated the expression of ST2 and SIGIRR and decreased the interaction of the membrane-bound ST2 (ST2L) with MyD88, and significantly reduced IL-33 levels in LPS-stimulated DCs. Simultaneously it increased the activation of transcription factor SP1and restored the basal level of ubiquitinated proteins in LPS-stimulated DCs. Moreover, EF24 inhibited trypsin- and chymotrypsin-like activity of proteasome by directly interacting with 26S proteasome. The results suggest that EF24 activates endogenous anti-inflammatory arm of IL-1R signaling, most likely by stabilizing SP1 against proteasomal degradation.

Bioactivities of EF24, a Novel Curcumin Analog: A Review

Curcumin is an attractive agent due to its multiple bioactivities. However, the low oral bioavailability and efficacy profile hinders its clinical application. To improve the bioavailability, many analogs of curcumin have been developed, among which EF24 is an excellent representative. EF24 has enhanced bioavailability over curcumin and shows more potent bioactivity, including anti-cancer, anti-inflammatory, and anti-bacterial. EF24 inhibits tumor growth by inducing cell cycle arrest and apoptosis, mainly through its inhibitory effect on the nuclear factor kappa B (NF-κB) pathway and by regulating key genes through microRNA (miRNA) or the proteosomal pathway. Based on the current structure, more potent EF24 analogs have been designed and synthesized. However, some roles of EF24 remain unclear, such as whether it induces or inhibits reactive oxygen species (ROS) production and whether it stimulates or inhibits the mitogen activated kinase-like protein (MAPK) pathway. This review summarizes the known biological and pharmacological activities and mechanisms of action of EF24.

Induction of gut proteasome activity in hemorrhagic shock and its recovery by treatment with diphenyldihaloketones CLEFMA and EF24

Multiorgan failure in hemorrhagic shock is triggered by gut barrier dysfunction and consequent systemic infiltration of proinflammatory factors. Our previous study has shown that diphenyldihaloketone drugs 4-[3,5-bis[(2-chlorophenyl)methylene]-4-oxo-1-piperidinyl]-4-oxo-2-butenoic acid (CLEFMA) and 3,5-bis[(2-fluorophenyl)methylene]-4-piperidinone (EF24) restore gut barrier dysfunction and reduce systemic inflammatory response in hemorrhagic shock. We investigated the effect of hemorrhagic shock on proteasome activity of intestinal epithelium and how CLEFMA and EF24 treatments modulate proteasome function in hemorrhagic shock. CLEFMA or EF24 (0.4 mg/kg) were given 1 h after withdrawing 50% of blood from Sprague-Dawley rats; no other resuscitation was provided. After another 5 h of compensation, small gut was collected to process tissue for proteasome activity, immunoblotting, and mRNA levels of genes responsible for unfolded-protein response (XBP1, ATF4, glucose-regulated protein of 78/95 kDa, and growth arrest and DNA damage inducible genes 153/34), polyubiquitin B and C, and immunoproteasome subunits β type-8 and -10 and proteasome activator subunit 1. We found that hemorrhagic shock induced proteasome activity in gut tissue and reduced the amounts of ubiquitinated proteins displayed on antiubiquitin immunoblots. However, simultaneous induction of unfolded-protein response or immunoproteasome genes was not observed. CLEFMA and EF24 treatments abolished the hemorrhagic shock-induced increase in proteasome activity. Further investigations revealed that the induction of proteasome in hemorrhagic shock is associated with disassembly of 26S proteasome; CLEFMA and EF24 prevented this disassembly. Consistent with these data, CLEFMA and EF24 reduced hemorrhagic shock-induced degradation of 20S substrate ornithine decarboxylase in gut tissue. These results suggest that activated proteasome plays an important role in ischemic gut pathophysiology, and it can be a druggable target in shock-induced gut dysfunction. NEW & NOTEWORTHY Ischemic injury to the gut is a trigger for the systemic inflammatory response and multiple organ failure in trauma and hemorrhagic shock. We show for the first time that hemorrhagic shock induces the gut proteasome activity by engendering 26S proteasome disassembly. Diphenyldihaloketones 4-[3,5-bis[(2-chlorophenyl)methylene]-4-oxo-1-piperidinyl]-4-oxo-2-butenoic acid and 3,5-bis[(2-fluorophenyl)methylene]-4-piperidinone treatment prevented the 26S disassembly. Understanding the role of proteasome in shock-associated gut injury will assist in the development of therapeutic means to address it.

Endotoxemia Results in Trapping of Transfused Red Blood Cells in Lungs with Associated Lung Injury

BACKGROUND

Red blood cell (RBC) transfusion is associated with organ failure, in particular in the critically ill. We hypothesized that endotoxemia contributes to increased trapping of RBCs in organs. Furthermore, we hypothesized that this effect is more pronounced following transfusion of stored RBCs compared with fresh RBCs.

METHODS

Adult male Sprague-Dawley rats were randomized to receive injection with lipopolysaccharide from E coli or vehicle and transfusion with fresh or stored biotinylated RBCs. After 24 h, the amount of biotinylated RBCs in organs was measured by flow cytometry, as well as the 24-h post-transfusion recovery. Markers of organ injury and histopathology of organs were assessed.

RESULTS

Endotoxemia resulted in systemic inflammation and organ injury. Following RBC transfusion, donor RBCs were recovered from the lung and kidney of endotoxemic recipients (1.2 [0.8-1.6]% and 2.2 [0.4-4.4]% of donor RBCs respectively), but not from organs of healthy recipients. Trapping of donor RBCs in the lung was associated with increased lung injury, but not with kidney injury. Stored RBCs induced organ injury in the spleen and yielded a lower 24-h post-transfusion recovery, but other effects of storage time were limited.

CONCLUSION

Endotoxemia results in an increased percentage of donor RBCs recovered from the lung and kidney, which is associated with lung injury following transfusion.

The salutary effects of diphenyldifluoroketone EF24 in liver of a rat hemorrhagic shock model

Background

Liver is a target for injury in low flow states and it plays a central role in the progression of systemic failure associated with hemorrhagic shock. Pharmacologic support can help recover liver function even after it has suffered extensive damage during ischemia and reperfusion phases. In this work we assessed the efficacy of a diphenyldifluoroketone EF24, an IKKβ inhibitor, in controlling hepatic inflammatory signaling caused by hemorrhagic shock in a rat model.

Methods

Sprague Dawley rats were bled to about 50% of blood volume. The hemorrhaged rats were treated with vehicle control or EF24 (0.4 mg/kg) after 1 h of hemorrhage without any accompanying resuscitation. The study was terminated after additional 5 h to excise liver tissue for biochemical analyses and histology.

Results

EF24 treatment alleviated hemorrhagic shock-induced histologic injury in the liver and restored serum transaminases to normal levels. Hemorrhagic shock induced the circulating levels of CD163 (a marker for macrophage activation) and CINC (an IL-8 analog), as well as myeloperoxidase activity in liver tissue. These markers of inflammatory injury were reduced by EF24 treatment. EF24 treatment also suppressed the expression of the Toll-like receptor 4, phospho-p65/Rel A, and cyclooxygenase-2 in liver tissues, indicating that it suppressed inflammatory pathway. Moreover, it reduced the hemorrhagic shock-induced increase in the expression of high mobility group box-1 protein. The evidence for apoptosis after hemorrhagic shock was inconclusive.

Conclusion

Even in the absence of volume support, EF24 treatment suppresses pro-inflammatory signaling in liver tissue and improves liver functional markers in hemorrhagic shock.

Remediation of hemorrhagic shock-induced intestinal barrier dysfunction by treatment with diphenyldihaloketones EF24 and CLEFMA

Gut is very sensitive to hypoperfusion and hypoxia, and deranged gastrointestinal barrier is implicated in systemic failure of various organs. We recently demonstrated that diphenyldihaloketone EF24 [3,5-bis(2-fluorobenzylidene)piperidin-4-one] improves survival in a rat model of hemorrhagic shock. In this study, we tested EF24 and its other analog CLEFMA (4-[3,5-bis(2-chlorobenzylidene)-4-oxo-piperidine-1-yl]-4-oxo-2-butenoic acid) for their effect on intestinal barrier dysfunction in hypovolemic shock. Hypovolemia was induced in rats by withdrawing 50% of blood. EF24 or CLEFMA (0.4 mg/kg i.p.) treatment was provided, without volume resuscitation, after 1 hour of hemorrhage. Ileum was collected 5 hours after the treatment to investigate the expression of tight junction proteins (zonula occludens, claudin, and occludin) and epithelial injury markers [myeloperoxidase, ileal lipid-binding protein (ILBP), CD163, and plasma citrulline]. The ileal permeability for dextran-fluoroisothiocyanate and Evan's blue dye was determined. EF24 and CLEFMA reduced the hypovolemia-induced plasma citrulline levels and the ileal expression of myeloperoxidase, ILBP, and CD163. The drugs also restored the basal expression levels of zonula occludens, claudin, and occludin, which were substantially deranged by hypovolemia. In ischemic ileum, the expression of phospho(tyrosine)-zonula occludens-1 was reduced, which was reinstated by EF24 and CLEFMA. In contrast, the drug treatments maintained the hypovolemia-induced expression of phospho(threonine)-occludin, but reduced that of phospho(tyrosine)-occludin. Both EF24 and CLEFMA treatments reduced the intestinal permeability enhanced by hypovolemia. EF24 and CLEFMA attenuate hypovolemic gut pathology and protect barrier function by restoring the status of tight junction proteins. These effects were observed in unresuscitated shock, implying the benefit of EF24 and CLEFMA in prehospital care of shock.