EOP, a newly synthesized ethyl pyruvate derivative, attenuates the production of inflammatory mediators via p38, ERK and NF-κB pathways in lipopolysaccharide-activated BV-2 microglial cells

Clovamide and Its Derivatives-Bioactive Components of Theobroma cacao and Other Plants in the Context of Human Health

Clovamide (N-caffeoyl-L-3,4-dihydroxyphenylalanine, N-caffeoyldopamine, N-caffeoyl-L-DOPA) is a derivative of caffeic acid, belonging to phenolamides (hydroxycinnamic acid amides). Despite a growing interest in the biological activity of natural polyphenolic substances, studies on the properties of clovamide and related compounds, their significance as bioactive components of the diet, as well as their effects on human health are a relatively new research trend. On the other hand, in vitro and in vivo evidence indicates the considerable potential of these substances in the context of maintaining human health or using them as pharmacophores. The name "clovamide" directly derives from red clover (Trifolium pratense L.), being the first identified source of this compound. In the human diet, clovamides are mainly present in chocolate and other cocoa-containing products. Furthermore, their occurrence in some medicinal plants has also been confirmed. The literature reports deal with the antioxidant, anti-inflammatory, neuroprotective, antiplatelet/antithrombotic and anticancer properties of clovamide-type compounds. This narrative review summarizes the available data on the biological activity of clovamides and their potential health-supporting properties, including prospects for the use of these compounds for therapeutic purposes.

The oxygenated products of cryptotanshinone by biotransformation with Cunninghamella elegans exerting anti-neuroinflammatory effects by inhibiting TLR 4-mediated MAPK signaling pathway

Cryptotanshinone (1), a major bioactive constituent in the traditional Chinese medicinal herb Dan-Shen Salvia miltiorrhiza Bunge, has been reported to possess remarkable pharmacological activities. To improve its bioactivities and physicochemical properties, in the present study, cryptotanshinone (1) was biotransformed with the fungus Cunninghamella elegans AS3.2028. Three oxygenated products (2-4) at C-3 of cryptotanshinone (1) were obtained, among them 2 was a new compound. Their structures were elucidated by comprehensive spectroscopic analysis including HRESIMS, NMR and ECD data. All of the biotransformation products (2-4) were found to inhibit significantly lipopolysaccharide-induced nitric oxide production in BV2 microglia cells with the IC₅₀ values of 0.16-1.16 μM, approximately 2-20 folds stronger than the substrate (1). These biotransformation products also displayed remarkably improved inhibitory effects on the production of inflammatory cytokines (IL-1β, IL-6, TNF-α, COX-2 and iNOS) in BV-2 cells via targeting TLR4 compared to substrate (1). The underlying mechanism of 2 was elucidated by comparative transcriptome analysis, which suggested that it reduced neuroinflammatory mainly through mitogen-activated protein kinase (MAPK) signaling pathway. Western blotting results revealed that 2 downregulated LPS-induced phosphorylation of JNK, ERK, and p38 in MAPK signaling pathway. These findings provide a basal material for the discovery of candidates in treating Alzheimer's disease.

Anticancer Effects of Baicalein in FRO Thyroid Cancer Cells Through the Up-regulation of ERK/p38 MAPK and Akt Pathway

BACKGROUND/AIM

The aim of the study was to evaluate the anticancer effects of baicalein in FRO anaplastic thyroid cancer (ATC) cells.

MATERIALS AND METHODS

FRO cells were treated with baicalein and viability was measured by the MTT assay. Cell apoptosis was observed by staining with Hoechst dye. The expression of apoptotic proteins (Bax, Bcl-2, PARP, cytochrome c, and caspase-3) and the inflammatory protein Cox-2 and the phosphorylation of MAPKs and Akt were determined by western blot.

RESULTS

Treatment with baicalein inhibited cell proliferation in a time-dependent manner and increased DNA fragmentation and apoptosis in FRO cells. Baicalein at 50 and 100 μM inhibited the expression of Bax, PARP, cytochrome c, cleaved caspase-3, and Cox-2, and increased the expression of Bcl-2. Baicalein increased the phosphorylation of ERK, p38 MAPK, and Akt and decreased JNK phosphorylation.

CONCLUSION

Baicalein caused anticancer effects in FRO ATC cells through induction of apoptosis and regulation of the MAPK and Akt pathway.

Anti-Inflammatory and Neuroprotective Effects of DIPOPA (N,N-Diisopropyl-2-Oxopropanamide), an Ethyl Pyruvate Bioisoster, in the Postischemic Brain

Ethyl pyruvate (EP) is a simple aliphatic ester of pyruvic acid and has been shown to have protective properties, which have been attributed to its anti-inflammatory, anti-oxidative, and anti-apoptotic functions. In an effort to develop better derivatives of EP, we previously synthesized DEOPA (N,N-diethyl-2-oxopropanamide, a novel isoster of EP) which has greater neuroprotective effects than EP, probably due to its anti-inflammatory and anti-excitotoxic effects. In the present study, we synthesized 3 DEOPA derivatives, in which its diethylamino group was substituted with diisopropylamino, dipropylamino, or diisobutylamino groups. Among them, DIPOPA (N,N-diisopropyl-2-oxopropanamide) containing diisopropylamino group had a greater neuroprotective effect than DEOPA or EP when administered intravenously to a rat middle cerebral artery occlusion (MCAO) model at 9 h after MCAO. Furthermore, DIPOPA had a wider therapeutic window than DEOPA and a marked reduction of infarct volume was accompanied by greater neurological and behavioral improvements. In particular, DIPOPA exerted robust anti-inflammatory effects, as evidenced by marked suppressions of microglia activation and neutrophil infiltration in the MCAO model, in microglial cells, and in neutrophil-endothelial cocultures at lower concentration, and did so more effectively than DEOPA. In particular, DIPOPA remarkably suppressed neutrophil infiltration into brain parenchyma, and this effect was attributed to the expressional inhibitions of cell adhesion molecules in neutrophils of brain parenchyma and in circulating neutrophils via NF-κB inhibition. Together, these results indicate the robust neuroprotective effects of DIPOPA are attributable to its anti-inflammatory effects and suggest that DIPOPA offers a potential therapeutic means of ameliorating cerebral ischemic injury and other inflammation-related pathologies.

Ethyl pyruvate and analogs as potential treatments for acute pancreatitis: A review of in vitro and in vivo studies

Ethyl pyruvate (EP) has been shown to improve outcomes from multiple organ dysfunction syndrome (MODS) in experimental animal models of critical illness. This review aimed to summarise in vitro and in vivo effects of EP analogs on acute pancreatitis (AP) with the objective of proposing medicinal chemistry modifications of EP for future research. In vitro studies showed that both sodium pyruvate and EP significantly reduced pancreatic acinar necrotic cell death pathway activation induced by multiple pancreatic toxins. In vivo studies using different murine AP models showed that EP (usually at a dose of 40 mg/kg every 6 h) consistently reduced pain, markers of pancreatic injury, systemic inflammation and MODS. There was also a significant increase in survival rate, even when EP was administered 12 h after disease induction (compared with untreated groups or those treated with Ringer's lactate solution). Experimental studies suggest that EP and analogs are promising drug candidates for treating AP. EP or analogs can undergo medicinal chemistry modifications to improve its stability and deliverability. EP or analogs could be evaluated as a supplement to intravenous fluid therapy in AP.

Discovery of a New Pterocarpan-Type Antineuroinflammatory Compound from Sophora tonkinensis through Suppression of the TLR4/NFκB/MAPK Signaling Pathway with PU.1 as a Potential Target

Neuroinflammation underlies many neuro-degenerative diseases. In this paper, we report the identification of a new pterocarpan-type anti-inflammatory compound named sophotokin isolated from Sophora tonkinensis. S. tonkinensis has been used traditionally for treatment of conditions related to inflammation. Our initial screening showed that sophotokin dose-dependently inhibits lipopolysaccharide (LPS)-stimulated production of NO, TNF-α, PGE2, and IL-1β in microglial cells. This antineuroinflammatory effect was associated with sophotokin's blockade of LPS-induced production of the inflammatory mediators iNOS and COX-2. Western blot and qPCR analysis demonstrated that sophotokin inhibits both the p38-MAPK and NF-κB signal pathways. Further studies revealed that sophotokin also suppresses the expression of cluster differentiation 14 (CD14) in the toll-like receptor 4 (TLR4) signaling pathway. Following down-regulation of MyD88 and TRAF6, sophotokin inhibits the activation of the NF-κB and MAPK signal pathways in LPS-induced BV-2 cells. In silico studies suggested that sophotokin could interact with PU.1-DNA complex through hydrogen binding at sites 1 and 2 of the complex, blocking the DNA binding. This suggests that PU.1 may be a potential target of sophotokin. Taken together, these results suggest that sophotokin may have therapeutic potential for diseases related to neuroinflammation. The mechanism of antineuroinflammatory effects involves inhibition of the TLR4 signal pathway at the sites of NF-κB and MAPK with PU.1 as a likely upstream target.

Idebenone Alleviates Neuroinflammation and Modulates Microglial Polarization in LPS-Stimulated BV2 Cells and MPTP-Induced Parkinson's Disease Mice

Background: Idebenone is an antioxidant and a coenzyme Q10 analog that has been used to treat neurodegeneration disease. Some studies show idebenone exerts anti-inflammatory effects. However, whether idebenone can be used to reduce the neuroinflammation in Parkinson’s disease (PD) has been little studied.

Methods: The study investigated the potential anti-inflammatory effects of idebenone in vitro and in vivo, using cell models of Lipopolysaccharide (LPS)-simulated BV2 cells and animal models of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD with or without idebenone. To verify how idebenone exerts its effects on the BV2 cell activation and PD model, we performed the mechanistic studies in vitro and in vivo.

Results:In vitro study showed that pretreatment with idebenone could attenuate the production of pro-inflammatory factors in LPS-stimulated BV2 cells and promoted a phenotypic switch from the M1 state to the M2 state. Mechanistically, idebenone reduced the activation of the MAPK and NF-κB signaling pathway upon LPS stimulation. Furthermore, in vivo experiments confirmed that pretreatment with idebenone could ameliorate MPTP-induced neurodegeneration and modulate microglia phenotypes through inhibition of the MAPK and NF-κB signaling pathway in the SN.

Conclusion: These results suggest that idebenone ameliorates the neurological deficits related to PD and this effect is partly mediated by inhibiting the neuroinflammation and modulating microglia phenotypes.

Metal-Free Oxidative Thioesterification of Methyl Ketones with Thiols/Disulfides for the Synthesis of α-Ketothioesters

A direct C_sp3-H bond oxidative thioesterification of methyl ketones with aromatic thiols/disulfides promoted by TBAI/K₂S₂O₈ has been developed. The reaction provides successfully a simple and efficient method for the synthesis of functionalized α-ketothioesters of aromatic thiols. This practical methodology exhibits readily available starting materials, large-scale applicability, synthetic application, and broad functional group tolerance. A possible mechanism for the transformation is proposed.

Thromboxane A2 receptor antagonist SQ29548 suppresses the LPS‑induced release of inflammatory cytokines in BV2 microglia cells via suppressing MAPK and NF‑κB signaling pathways

Inflammation in the brain, characterized by the activation of microglia, is hypothesized to participate in the pathogenesis of neuronal disorders. It is proposed that thromboxane A2 receptor (TXA2R) activation is involved in thrombosis/hemostasis and inflammation responses. In the present study, the anti‑inflammatory effects of SQ29548 on lipopolysaccharide (LPS)‑stimulated BV2 microglial cells and its molecular mechanisms were investigated. In the BV2 cell line, LPS‑stimulated nitric oxide (NO) and inflammatory cytokine release, and the phosphorylation of mitogen‑activated protein kinases (MAPKs) and the nuclear factor (NF)‑κB were assessed using an NO assay kit, reverse transcription-quantitative polymerase chain reaction and western blotting, respectively. In vitro studies demonstrated that SQ29548 inhibited LPS‑stimulated BV2 activation and reduced the mRNA expression levels of interleukin (IL)‑1β, IL‑6, tumor necrosis factor‑α and inducible NO synthase via inhibition of MAPKs and the NF‑κB signaling pathway. SQ29548 inhibited the LPS‑induced inflammatory response by blocking MAPKs and NF‑κB activation in BV2 microglial cells.

Salvianolic Acids for Injection (SAFI) suppresses inflammatory responses in activated microglia to attenuate brain damage in focal cerebral ischemia

BACKGROUND

Inflammatory reactions induced by microglia in the brain play crucial roles in ischemia/reperfusion (I/R) cerebral injuries. Microglia activation has been shown to be closely related to TLR4/NF-κB signal pathways. Salvianolic acids for injection (SAFI) have been used in clinical practice to treat ischemic stroke with reported neuroprotective effects; however, the underlying mechanisms are still uncertain.

OBJECTIVE AND METHODS

First, we studied the effect of SAFI on inflammatory responses in LPS-stimulated BV-2 microglia. Then, to discover whether the beneficial in vitro effects of SAFI lead to in vivo therapeutic effects, an MCAO (Middle cerebral artery occlusion) rat model was further employed to elucidate the probable mechanism of SAFI in treating ischemic stroke. Rats in the SAFI group were given SAFI (23 or 46mg/kg) before I/R injury.

RESULTS

The results showed that SAFI treatment significantly decreased neuroinflammation and the infarction volume compared with the vehicle group. Activation of microglia cells was reduced, and TLR4/NF-κB signals, which were markedly inhibited by SAFI treatment in ischemic hemisphere, were accompanied by reduced expression and release of cytokines IL-1β and IL-6.

CONCLUSION

This study provides evidence that SAFI effectively protects the brain after cerebral ischemia, which may be caused by attenuating inflammation in microglia.

Anti-inflammatory and anti-excitoxic effects of diethyl oxopropanamide, an ethyl pyruvate bioisoster, exert robust neuroprotective effects in the postischemic brain

Ethyl pyruvate (EP) is a simple aliphatic ester of pyruvic acid and has been shown to have robust neuroprotective effects via its anti-inflammatory, anti-oxidative, and anti-apoptotic functions. In an effort to develop novel EP derivatives with greater protective potencies than EP, we generated four EP isosteres, among them the neuroprotective potency of N,N-diethyl-2-oxopropanamide (DEOPA), in which the ethoxy group of EP was replaced with diethylamine, was far greater than that of EP. When DEOPA was administered intravenously (5 mg/kg) to rat middle cerebral artery occlusion (MCAO) model at 6 hrs post-surgery, it suppressed infarct formation, ameliorated neurological and sensory/motor deficits, and inhibited microglial activation and neutrophil infiltrations in the postischemic brain more effectively than EP. In particular, DEOPA markedly suppressed LPS-induced nitrite production and cytokine/chemokine inductions in microglia, neutrophils, and endothelial cells and these effects are attributable to inhibition of the activity of NF-κB by suppressing IκB-α degradation and p65 to DNA binding. In addition, DEOPA suppressed NMDA-induced neuronal cell death in primary cortical neuron cultures by NAD replenishment and suppression of NF-κB activity. Together, these results indicate DEOPA has multi-modal protective effects against ischemic brain damage targeting numerous cell types in the brain and also against other inflammation-related diseases.

Protective Effect of Cactus Cladode Extracts on Peroxisomal Functions in Microglial BV-2 Cells Activated by Different Lipopolysaccharides

In this study, we aimed to evaluate the antioxidant and anti-inflammatory properties of Opuntia ficus-indica cactus cladode extracts in microglia BV-2 cells. Inflammation associated with microglia activation in neuronal injury can be achieved by LPS exposure. Using four different structurally and biologically well-characterized LPS serotypes, we revealed a structure-related differential effect of LPS on fatty acid β-oxidation and antioxidant enzymes in peroxisomes: Escherichia coli-LPS decreased ACOX1 activity while Salmonella minnesota-LPS reduced only catalase activity. Different cactus cladode extracts showed an antioxidant effect through microglial catalase activity activation and an anti-inflammatory effect by reducing nitric oxide (NO) LPS-dependent production. These results suggest that cactus extracts may possess a neuroprotective activity through the induction of peroxisomal antioxidant activity and the inhibition of NO production by activated microglial cells.

Deferoxamine attenuates lipopolysaccharide-induced inflammatory responses and protects against endotoxic shock in mice

To examine the role of the intracellular labile iron pool (LIP) in the induction of inflammatory responses, we investigated the anti-inflammatory effect of the iron chelator deferoxamine (DFO) on lipopolysaccharide (LPS)-induced inflammatory responses in RAW264.7 macrophage cells and endotoxic shock in mice in the present study. Our data showed that DFO significantly decreased LPS-induced LIP and ROS upregulation. We then found that DFO inhibited phosphorylation of MAP kinases such as ERK and p38 and also inhibited the activation of NF-κB induced by LPS. Furthermore, the production of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), nitric oxide (NO) and prostaglandin E2 (PGE2) induced by LPS was inhibited by DFO in RAW264.7 macrophages. Administration of DFO significantly decreased the mortality and improved the survival of septic mice with lethal endotoxemia in LPS-injected mice. These results demonstrate that iron plays a pivotal role in the induction of inflammatory responses and against septic shock. DFO has effective inhibitory effect on the production of inflammatory mediators via suppressing activation of MAPKs and NF-κB signaling pathways; it also has a protective effect on LPS-induced endotoxic shock in mice. Our findings open doors to further studies directed at exploring a new class of drugs against septic shock or other inflammatory diseases by modulating cellular chelatable iron.