Diphenyldifluoroketone EF24 Suppresses Pro-inflammatory Interleukin-1 receptor 1 and Toll-like Receptor 4 in lipopolysaccharide-stimulated dendritic cells

Negative regulator IL-1 receptor 2 (IL-1R2) and its roles in immune regulation of autoimmune diseases

The decoy receptor interleukin 1 receptor 2 (IL-1R2), also known as CD121b, has different forms: membrane-bound (mIL-1R2), soluble secreted (ssIL-1R2), shedded (shIL-1R2), intracellular domain (IL-1R2ICD). The different forms of IL-1R2 exert not exactly similar functions. IL-1R2 can not only participate in the regulation of inflammatory response by competing with IL-1R1 to bind IL-1 and IL-1RAP, but also regulate IL-1 maturation and cell activation, promote cell survival, participate in IL-1-dependent internalization, and even have biological activity as a transcriptional cofactor. In this review, we provide a detailed description of the biological characteristics of IL-1R2 and discuss the expression and unique role of IL-1R2 in different immune cells. Importantly, we summarize the role of IL-1R2 in immune regulation from different autoimmune diseases, hoping to provide a new direction for in-depth studies of pathogenesis and therapeutic targets in autoimmune diseases.

Bis-chalcones: A review of synthetic methodologies and anti-inflammatory effects

Chalcones are bioactive molecules of natural and synthetic sources, whose physicochemical properties, reactivity, and biological activities are well-known among the scientific community. However, there are many molecules strictly related to chalcones with significantly less recognition like bis-chalcones. Several studies indicated that bis-chalcones have advantages over chalcones in specific bioactivities like anti-inflammatory activity. This review article describes the chemical structure and chemical properties of bis-chalcones, as well as the methods reported in the literature for the synthesis of these compounds highlighting the most recent developments. Finally, the anti-inflammatory activity of bis-chalcones is described, emphasizing the active structures found in literature and their mechanisms of action.

EF-24 inhibits TPA-induced cellular migration and MMP-9 expression through the p38 signaling pathway in cervical cancer cells

Diphenyl difluoroketone (EF-24), a synthetic curcumin analog, has enhanced bioavailability over curcumin. EF-24 acts more powerful bioactivity for anti-inflammatory and anti-cancer activity. However, the effects and mechanism of EF-24 on cervical cancer has not been fully investigated. Herein, this study evaluated the effects of EF-24 on TPA-induced cellular migration of cervical cancer. The results showed that EF-24 substantially reduced the cellular migration and cellular invasion of the HeLa and SiHa cells. Moreover, gelatin zymography, western blotting analyses and real-time PCR revealed that EF-24 suppressed Matrix metalloproteinase-9 (MMP-9) activity, protein expression and mRNA levels. Mechanistically, EF-24 inhibited the phosphorylation of the p38 signaling pathway. In conclusion, EF-24 inhibited TPA-induced cellular migration and cellular invasion of cervical cancer cell lines through modulating MMP-9 expression via downregulating signaling p38 pathway and EF-24 may have potential to serve as a chemopreventive agent of cervical cancer.

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.

Dienone Compounds: Targets and Pharmacological Responses

The biological responses to dienone compounds with a 1,5-diaryl-3-oxo-1,4-pentadienyl pharmacophore have been studied extensively. Despite their expected general thiol reactivity, these compounds display considerable degrees of tumor cell selectivity. Here we review in vitro and preclinical studies of dienone compounds including b-AP15, VLX1570, RA-9, RA-190, EF24, HO-3867, and MCB-613. A common property of these compounds is their targeting of the ubiquitin–proteasome system (UPS), known to be essential for the viability of tumor cells. Gene expression profiling experiments have shown induction of responses characteristic of UPS inhibition, and experiments using cellular reporter proteins have shown that proteasome inhibition is associated with cell death. Other mechanisms of action such as reactivation of mutant p53, stimulation of steroid receptor coactivators, and induction of protein cross-linking have also been described. Although unsuitable as biological probes due to widespread reactivity, dienone compounds are cytotoxic to apoptosis-resistant tumor cells and show activity in animal tumor models.

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.

Curcumin and derivatives function through protein phosphatase 2A and presenilin orthologues in Dictyostelium discoideum

Natural compounds often have complex molecular structures and unknown molecular targets. These characteristics make them difficult to analyse using a classical pharmacological approach. Curcumin, the main curcuminoid of turmeric, is a complex molecule possessing wide-ranging biological activities, cellular mechanisms and roles in potential therapeutic treatment, including Alzheimer's disease and cancer. Here, we investigate the physiological effects and molecular targets of curcumin in Dictyostelium discoideum. We show that curcumin exerts acute effects on cell behaviour, reduces cell growth and slows multicellular development. We employed a range of structurally related compounds to show the distinct role of different structural groups in curcumin's effects on cell behaviour, growth and development, highlighting active moieties in cell function, and showing that these cellular effects are unrelated to the well-known antioxidant activity of curcumin. Molecular mechanisms underlying the effect of curcumin and one synthetic analogue (EF24) were then investigated to identify a curcumin-resistant mutant lacking the protein phosphatase 2A regulatory subunit (PsrA) and an EF24-resistant mutant lacking the presenilin 1 orthologue (PsenB). Using in silico docking analysis, we then showed that curcumin might function through direct binding to a key regulatory region of PsrA. These findings reveal novel cellular and molecular mechanisms for the function of curcumin and related compounds.

Summary: To unlock the therapeutic potential of curcumin and related compounds, we employ a tractable model system to characterise their cellular and molecular effects and propose novel targets implicated in disease.

Attenuation of thioacetamide-induced hepatocellular injury by short-term repeated injections associated with down-regulation of metabolic enzymes and relationship with MHC class II-presenting cells

The liver is the primary organ participating in the metabolism of xenobiotics and is therefore an important target in the safety assessment of drugs, chemicals and environmental toxins. Drug-induced liver injury (DILI) has recently become widely recognized in human medicine as an adverse event. The progression of DILI often involves "damage-associated molecular patterns" (DAMPs) of gene and protein expression such as high-mobility group boxes (HMGBs), S100 proteins and heat shock proteins (Hsp). DAMPs are released from injured or necrotic cells and are bound to Toll-like receptors (TLRs) and modulate inflammatory reactions. Previously, in thioacetamide (TAA; 300mg/kg body weight, single injection)-induced rat liver, we demonstrated that the expressions of DAMPs, TLR4 and major histocompatibility complex (MHC) class II were simultaneously increased, accompanied with progression of hepatocellular injury and inflammation. Here we investigated the association of DILI and DAMPs, TLRs and MHC class II by using rat livers repeated injections with TAA (100mg/kg body weight, once, three times). Two days after TAA single injection, centrilobular hepatocellular necrosis with infiltration of mononuclear cells was observed, being paralleled with increase in serum levels of aspartate transaminase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP). However, two days after duplicate and triplicate injections, only mild degenerative change of hepatocytes and slight infiltration of mononuclear cells were seen in the affected centrilobular area. Serum levels of AST, ALT and ALP were also decreased to the same levels of control. mRNA expressions of DAMPs (HMGBs, S100A4 and Hsp 70-2), TLR4 and MHC class II tended to be increased only on single injection, although the number of MHC class II-positive cells in the centrilobular area was still increased on each examination point. The analysis of enzymes (CYP2E1 and Flavin monooxygenase (FMO) 3), which metabolize TAA in hepatocytes, showed a significant decrease in FMO3 on the duplicate and triplicate injections. Autophagy and regulatory T cells were not significantly changed for the attenuation of hepatocyte injury. Collectively, these results suggest that hepatocytes may adapt accumulation of the toxicant by changing their enzyme functions; furthermore, MHC class II cells, which still showed increased number in the duplicate and triplicate injections, may be related with protection from the toxicant.