The p38 MAPK inhibitor JLU1124 inhibits the inflammatory response induced by lipopolysaccharide through the MAPK-NF-κB pathway in RAW264.7 macrophages

Exogenous ATP modulates PGE2 release in macrophages through sustained phosphorylation of CDK9 and p38 MAPK

An important mediator of inflammation is prostaglandin E₂ (PGE₂ ), whose levels are determined by the activity of the enzyme cyclooxygenase (COX). Of the two isoforms of the enzyme, COX-2 has been shown to be induced in macrophages during inflammation. Although general COX inhibitors, belonging to the class of nonsteroidal anti-inflammatory drugs, or specific COX-2 inhibitors, called coxibs, are useful in the control of acute inflammation, adverse reactions were seen when used chronically in the treatment of rheumatoid arthritis or neurodegenerative diseases. Extracellular ATP (eATP) has been reported as a damage-associated molecular pattern signal. In this report, we show that eATP synergistically increases the levels of COX-2 enzyme and PGE₂ in LPS-activated RAW264.7 macrophages and human monocytes. Activation of macrophages also occurred when cultured in media obtained from dying neurons that contained higher levels of ATP. We show that eATP increases the levels of COX-2 protein, which is sustained up to 36 h poststimulation. This is in turn due to sustained levels of phosphorylated, or activated, cyclin-dependent kinase 9 and p38 MAPK in ATP-treated cells compared to LPS-stimulated cells. The eATP-dependent increase in COX-2/PGE₂ levels in LPS-activated RAW264.7 cells could be abolished using antagonists for purinergic P2X7 -and P2Y6 receptors. Similarly, the increase in COX-2/PGE₂ levels in the peritoneum of LPS-treated mice could be significantly abolished in mice that were preinjected with the nonspecific P2 receptor antagonist, suramin. P2 receptor antagonists, therefore, should be explored in our search for an ideal anti-inflammatory candidate.

Protocatechuic Aldehyde Attenuates UVA-Induced Photoaging in Human Dermal Fibroblast Cells by Suppressing MAPKs/AP-1 and NF-κB Signaling Pathways

Ultraviolet radiation (UV) is a major causative factor of DNA damage, inflammatory responses, reactive oxygen species (ROS) generation and a turnover of various cutaneous lesions resulting in skin photoaging. The purpose of this study is to investigate the protective effect of protocatechuic aldehyde (PA), which is a nature-derived compound, against UVA-induced photoaging by using human dermal fibroblast (HDF) cells. In this study, our results indicated that PA significantly reduced the levels of intracellular ROS, nitric oxide (NO), and prostaglandins-E₂ (PGE₂) in UVA-irradiated HDF cells. It also inhibited the levels of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expression. Besides, PA significantly suppressed the expression of matrix metalloproteinases-1 (MMP-1) and pro-inflammatory cytokines and promoted collagen synthesis in the UVA-irradiated HDF cells. These events occurred through the regulation of activator protein 1 (AP-1), nuclear factor-κB (NF-κB), and p38 signaling pathways in UVA-irradiated HDF cells. Our findings suggest that PA enhances the protective effect of UVA-irradiated photoaging, which is associated with ROS scavenging, anti-wrinkle, and anti-inflammatory activities. Therefore, PA can be a potential candidate for the provision of a protective effect against UVA-stimulated photoaging in the pharmaceutical and cosmeceutical industries.

Javamide-II Inhibits IL-6 without Significant Impact on TNF-alpha and IL-1beta in Macrophage-Like Cells

The main aim of this study is to find a therapeutic compound to inhibit IL-6, not TNF-alpha and IL-1beta, in macrophage-like cells, because the high-levels of IL-6 production by macrophages are reported to cause unfavorable outcomes under several disease conditions (e.g., autoimmune diseases, and acute viral infections, including COVID-19). In this study, the potential effects of javamide-II on IL-6, IL-1beta and TNF-alpha productions were determined using their ELISA kits in macrophage-like THP-1 cells. Western blots were also performed using the same cells, to determine its effects on signaling pathways (ERK, p38, JNK, c-Fos, ATF-2, c-Jun and NF-κB p65). At concentrations of 0.2–40 µM, javamide-II inhibited IL-6 production significantly in the THP-1 cells (IC₅₀ of 0.8 µM) (P < 0.02). However, javamide-II did not inhibit IL-1beta or TNF-alpha productions much at the same concentrations. In addition, the treatment of javamide-II decreased the phosphorylation of p38 without significant effects on ERK and JNK phosphorylations in the THP-1 cells. Furthermore, the p38 inhibition, followed by the reduction of ATF-2 phosphorylation (not c-Fos, c-Jun or NF-κB p65), led to the suppression of IL-6 mRNA expression in the cells (P < 0.02). The data indicate that javamide-II may be a potent compound to inhibit IL-6 production via suppressing the p38 signal pathway, without significant effects on the productions of TNF-alpha and IL-1beta in macrophage-like THP-1 cells.

Anti-nociceptive and anti-inflammatory effects of the ethanol extract of Arenga pinnata (Wurmb) Merr. fruit

ETHNOPHARMACOLOGICAL RELEVANCE

Arenga pinnata (Wurmb) Merr. is a medicinal and edible plant belonging to family Palmae. The fruits of this plant were used in traditional folk medicine due to its analgesia and anti-inflammatory activities. This study aimed to investigate the analgesic and anti-inflammatory properties and the mechanism of the ethanol extract of A. pinnata (Wurmb) Merr. fruit (EAF) on different experimental models.

MATERIALS AND METHODS

High-performance liquid chromatography (HPLC) was used to determine the chromatographic profile and to analyze the composition of EAF. In the acute toxicity test, all mice were orally administered EAF at a maximum dosage of 26 g/kg and were then monitored for 14 days. The potential analgesic activity of EAF was evaluated by using animal pain models, namely the acetic acid-induced writhing test and the hot plate test in mice. The underlying mechanisms of analgesia were determined by pretreating with naloxone, capsaicin and cinnamaldehyde to evaluate the involvement of the opioid system and transient receptor potential channels (TRP channels). The anti-inflammatory activity of EAF was evaluated by using the following inflammatory animal models: xylene-induced ear edema in mice and Complete Freund's adjuvant (CFA)-induced paw swelling in rats. EAF was orally administered at the doses of 1.625, 3.25 and 6.5 g/kg in mice and 1.125, 2.25 and 4.5 g/kg in rats. The underlying mechanism of the anti-inflammatory activity was determined by enzyme-linked immunosorbent assay (ELISA) kits and real time-PCR used to measure the expression levels of interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), prostaglandin E2 (PGE₂) and cyclooxygenase-2 (COX-2). Western blot analysis was used to determine the expression levels of proteins related to the nuclear factor-κB (NF-κB) and mitogen-activated protein kinases (MAPK) signaling pathways in paw tissues.

RESULTS

Five compounds, namely (5-(hydroxymethyl) furan-2-yl) methanediol,4'-hydroxy-N-(4-hydroxy-3-methoxybenzoyl)-3',5'-dimethoxybenzamide, (+)-lyonirenisol-3a-O-β-D-glucopyranoside, (-)-lyonirenisol-3a-O-β-glucopyranoside and liquiritin, were firstly identified from A. pinnata (Wurmb) Merr. fruit by HPLC-UV analysis. In the acute toxicity test, no treatment-related toxicological signs or mortality was observed in mice administered doses up to 26 g/kg. Bodyweight was not obviously different among the treatment groups and the vehicle group. EAF significantly inhibited the pain response induced by acetic acid and increased the latency time in the hot plate test in mice. The anti-nociception effect of EAF in the formalin test was not alleviated by pretreatment with naloxone. However, the nociception induced by injection with capsaicin and cinnamaldehyde was significantly reduced by EAF. Compared with vehicle treatment, EAF significantly inhibited the formation of xylene-induced ear edema and CFA adjuvant-induced paw swelling. EAF markedly inhibited the production of IL-1β, TNF-α, PGE₂ and IL-6 induced by CFA in paw tissues. Furthermore, the phosphorylation of IKKα, IKKβ, IκBα, p38, ERK1/2, and JNK and the nuclear translation of NF-κB p65 induced by CFA in paw tissues were significantly inhibited by EAF treatment compared with vehicle treatment.

CONCLUSION

For the first time, this study provides pharmacological evidence for the analgesic and anti-inflammatory activities of EAF and the underlying mechanism, suggesting that EAF might be a potential candidate for reducing pain and inflammatory disorders.

Effect of Herb-Partitioned Moxibustion on Autophagy and Immune-Associated Gene Expression Profiles in a Rat Model of Crohn's Disease

Objective

To investigate the immune regulation mechanism of herb-partitioned moxibustion in rats with Crohn's disease (CD) focusing on autophagy.

Methods

Rats were randomly divided into normal (N) group, CD model (M) group, CD model with herb-partitioned moxibustion (MM) group, normal with herb-partitioned moxibustion (NM) group, CD model with mesalazine (western medicine, Med ) group, and normal saline (NS) group, with 10 rats in each group. The CD model rats were prepared by trinitrobenzene sulphonic expect for the N group and NM group. After the CD rats model were established, the rats in the MM and NM groups were treated with herb-partitioned moxibustion at Tianshu (ST25) and Qihai (CV6) acupoints once daily for 7 days, and rats in the Med and NS groups were respectively treated with mesalazine enteric coated tablet and normal saline once daily for 7 days. After intervention, hematoxylin-eosin staining was used to observe the histological changes of colon; RNA sequencing was used to observe the changes in autophagy- and immune-associated gene expression profiles. In addition, autophagy- and immune-associated cytokines and signaling pathways in CD rats were also screened.

Results

HPM significantly increased the body weight of CD rats (P<0.01) and improved the pathological injury of colon in CD rats (P<0.01). HPM also changed the expression of many autophagy- and immune-associated genes, especially downregulating the expression of autophagy-associated Nod2, Irgm genes as well as the receptor of immune-associated Il12b, Il22 (Il12rb1, Il22ra2) genes in the colon of CD rats. HPM also changed the enrichment levels of differentially expressed genes in the human T-cell leukemia virus type-1 infection pathway, the Epstein-Barr virus infection pathway, and the cell adhesion molecule pathway. In addition, the expression levels of Nod2, Irgm, IL-12b, and IL-22 mRNA were increased (all P< 0.01) in the M group compared to the N group, while the expression levels of Nod2, Irgm, IL-12b, and IL-22 mRNA were decreased (P<0.05 or P<0.01) in the MM and Med groups compared to the M group.

Conclusion

Herb-partitioned moxibustion may effectively attenuate intestinal inflammation and promote the repair of colon mucosal injury of CD rats through the regulation of autophagy- and immune-associated gene expression and signaling pathways.

CQMUH-011, a novel adamantane sulfonamide compound, inhibits lipopolysaccharide- and D-galactosamine-induced fulminant hepatic failure in mice

CQMUH-011, a novel adamantane sulfonamide compound, was shown to suppress macrophage activation and proliferation in our previous study. However, it is unknown whether CQMUH-011 has anti-inflammatory and hepatoprotective properties. In this study, we investigated the potential effects and mechanisms of CQMUH-011 on lipopolysaccharide (LPS)-induced RAW264.7 cell activation in vitro and LPS- and D-galactosamine (D-GalN)-induced fulminant hepatic failure (FHF) in vivo. The results showed that in RAW264.7 cells challenged by LPS, CQMUH-011 inhibited cell proliferation and induced cell cycle arrest and apoptosis. Furthermore, CQMUH-011 reduced tumor necrosis factor (TNF)-α and interleukin (IL)-1β production and down-regulated the overexpression of toll-like receptor 4 (TLR4) and nuclear factor (NF)-κB induced by LPS in RAW264.7 cells. In vivo, CQMUH-011 reduced serum levels of aspartic aminotransferase and alanine transaminase and improved the mortality and hepatic pathological damage induced by LPS/D-GalN in mice. Moreover, CQMUH-011 significantly inhibited the serum levels of proinflammatory mediators, including TNF-α, IL-6, IL-1β, nitric oxide (NO), and prostaglandin E2 (PGE₂), and down-regulated the protein expression of TLR4, p38 mitogen-activated protein kinases, NF-κB, NF-κB inhibitor α (IκBα), IκB kinase β (IKKβ), cyclooxygenase-2 (COX-2) and inducible NO synthases (iNOS) induced by LPS/D-GalN in mice. In conclusion, these results demonstrated that CQMUH-011 has a notable anti-inflammatory effect and protects mice from LPS/D-GalN-induced FHF and that the molecular mechanisms might be related to the inhibition of the TLR4/NF-κB signaling pathway activation, the subsequent decrease in proinflammatory mediator production, and the inhibition of macrophage activation.

Sesamin ameliorates lipopolysaccharide/d-galactosamine-induced fulminant hepatic failure by suppression of Toll-like receptor 4 signaling in mice

Sesamin has been described to exert anti-oxidant and anti-inflammatory properties. In present study, we investigated the potential effects and mechanisms of sesamin on lipopolysaccharide (LPS)-induced fulminant hepatic failure (FHF) in d-galactosamine (D-GalN)-sensitized mice. Our results showed that pretreatment with sesamin dose-dependently improved LPS/D-GalN-induced mortality and liver injury as indicated by reduced serum levels of aminotransferases and alleviated pathological damage as well as hepatocyte apoptosis in mice. Additionally, sesamin markedly attenuated LPS/D-GalN-induced adhesion molecules expression, and decreased neutrophils recruitment. Furthermore, sesamin inhibited LPS-induced tumor necrosis factor-alpha (TNF-α) production, p38 mitogen-activated protein kinases (MAPK) and NF-κB activation, and Toll like receptor (TLR) 4 expression in mice and in RAW264.7 macrophage cells. In summary, these results demonstrate that sesamin protects mice from LPS-induced FHF and the molecular mechanisms may down-regulate the expression of TLR4, block MAPK and NF-κB activation, decrease the production of TNF-α.

Anti-inflammatory activity of AP-SF, a ginsenoside-enriched fraction, from Korean ginseng

BACKGROUND

Korean ginseng is an ethnopharmacologically valuable herbal plant with various biological properties including anticancer, antiatherosclerosis, antidiabetic, and anti-inflammatory activities. Since there is currently no drug or therapeutic remedy derived from Korean ginseng, we developed a ginsenoside-enriched fraction (AP-SF) for prevention of various inflammatory symptoms.

METHODS

The anti-inflammatory efficacy of AP-SF was tested under in vitro inflammatory conditions including nitric oxide (NO) production and inflammatory gene expression. The molecular events of inflammatory responses were explored by immunoblot analysis.

RESULTS

AP-SF led to a significant suppression of NO production compared with a conventional Korean ginseng saponin fraction, induced by both lipopolysaccharide and zymosan A. Interestingly, AP-SF strongly downregulated the mRNA levels of genes for inducible NO synthase, tumor necrosis factor-α, and cyclooxygenase) without affecting cell viability. In agreement with these observations, AP-SF blocked the nuclear translocation of c-Jun at 2 h and also reduced phosphorylation of p38, c-Jun N-terminal kinase, and TAK-1, all of which are important for c-Jun translocation.

CONCLUSION

Our results suggest that AP-SF inhibits activation of c-Jun-dependent inflammatory events. Thus, AP-SF may be useful as a novel anti-inflammatory remedy.

ATF-2/CREB/IRF-3-targeted anti-inflammatory activity of Korean red ginseng water extract

ETHNOPHARMACOLOGICAL RELEVANCE

Korean Red Ginseng (KRG) is one of the representative traditional herbal medicines prepared from Panax ginseng Meyer (Araliaceae) in Korea. It has been reported that KRG exhibits a lot of different biological actions such as anti-aging, anti-fatigue, anti-stress, anti-atherosclerosis, anti-diabetic, anti-cancer, and anti-inflammatory activities. Although systematic studies have investigated how KRG is able to ameliorate various inflammatory diseases, its molecular inhibitory mechanisms had not been carried out prior to this study.

MATERIALS AND METHODS

In order to investigate these mechanisms, we evaluated the effects of a water extract of Korean Red Ginseng (KRG-WE) on the in vitro inflammatory responses of activated RAW264.7 cells, and on in vivo gastritis and peritonitis models by analyzing the activation events of inflammation-inducing transcription factors and their upstream kinases.

RESULTS

KRG-WE reduced the production of nitric oxide (NO), protected cells against NO-induced apoptosis, suppressed mRNA levels of inducible NO synthase (iNOS), cyclooxygenase (COX)-2, and interferon (IFN)-β, ameliorated EtOH/HCl-induced gastritis, and downregulated peritoneal exudate-derived NO production from lipopolysaccharide (LPS)-injected mice. The inhibition of these inflammatory responses by KRG-WE was regulated through the suppression of p38, c-Jun N-terminal kinase (JNK), and TANK-binding kinase 1 (TBK1) and by subsequent inhibition of activating transcription factor (ATF)-2, cAMP response element-binding protein (CREB), and IRF-3 activation. Of ginsensides included in this extract, interestingly, G-Rc showed the highest inhibitory potency on IRF-3-mediated luciferase activity.

CONCLUSION

These results strongly suggest that the anti-inflammatory activities of KRG-WE could be due to its inhibition of the p38/JNK/TBK1 activation pathway.