Methyl lucidone inhibits airway inflammatory response by reducing TAK1 activity in human bronchial epithelial NCI-H292 cells.

Background: Methyl lucidone (ML), a methyl derivative of lucidone, has anti-inflammatory properties. However, the molecular mechanisms that reduce the inflammatory effect of ML in human lung epithelial cells remain unkown. This study aimed to elucidate the molecular mechanisms underlying the anti-inflammatory effect of ML. Methods: Four compounds (ML, methyl linderone, kanakugiol, and linderone) from Lindera erythrocarpa Makino were evaluated for their ability to reduce MUC5AC secretion levels in phorbol-12-myristate-13-acetate (PMA)-stimulated NCI-H292 cells using ELISA. The expression and secretion levels of inflammatory response-related proteins were analyzed using quantitative reverse transcription-PCR, ELISA, and western blotting. To determine whether ML directly regulates TGF-ß-activated kinase 1 (TAK1), we performed an in vitro kinase assay. Results: ML treatment effectively reduced the levels of inflammatory cytokines, including interleukin-1ß and TNF-α, increased by stimulation. Furthermore, ML downregulated the pathway cascade of both IκB kinase (IKK)/NF-κB and p38 mitogen-activated protein (MAP) kinase/CREB by inhibiting the upstream kinase TAK1. An in vitro kinase analysis confirmed that ML treatment significantly reduced the kinase activity of TAK1. Conclusion: ML pretreatment repressed the PMA-stimulated inflammation reaction by reducing the TAK1-mediated IKK/NF-κB and p38 MAP kinase/CREB signaling. These findings suggest that ML may improve respiratory health and can be used as a dietary supplement or functional food to prevent inflammatory lung diseases.

Garcinia mangostana Suppresses Triacylglycerol Synthesis in Hepatocytes and Enterocytes.

Regulation of diacylglycerol acyltransferase (DGAT) and pancreatic lipase (PL) activities is important in the treatment of triacylglycerol (TG)-related metabolic diseases. Garcinia mangostana, also known as mangosteen, is a traditional medicine ingredient used in the treatment of inflammation in Southeast Asia. In this study, The ethanolic extract of G. mangostana peel inhibited human recombinant DGAT1 and DGAT2, and PL enzyme activities in vitro. The inhibitory activity of DGAT1 and DGAT2 enzymes of four representative bioactive substances in mangosteen was confirmed. In addition, G. mangostana was confirmed to suppress the serum TG levels in C57 mice by inhibiting the absorption and synthesis of TG in the gastrointestinal tract. Through this study, it was revealed that G. mangostana extract could be useful for the prevention and amelioration of TG-related metabolic diseases such as obesity and fatty liver.

Black Ginseng Extract Exerts Potentially Anti-Asthmatic Activity by Inhibiting the Protein Kinase Cθ-Mediated IL-4/STAT6 Signaling Pathway.

Asthma is a chronic inflammatory lung disease that causes respiratory difficulties. Black ginseng extract (BGE) has preventative effects on respiratory inflammatory diseases such as asthma. However, the pharmacological mechanisms behind the anti-asthmatic activity of BGE remain unknown. To investigate the anti-asthmatic mechanism of BGE, phorbol 12-myristate 13-acetate plus ionomycin (PMA/Iono)-stimulated mouse EL4 cells and ovalbumin (OVA)-induced mice with allergic airway inflammation were used. Immune cells (eosinophils/macrophages), interleukin (IL)-4, -5, -13, and serum immunoglobulin E (IgE) levels were measured using an enzyme-linked immunosorbent assay. Inflammatory cell recruitment and mucus secretion in the lung tissue were estimated. Protein expression was analyzed via Western blotting, including that of inducible nitric oxide synthase (iNOS) and the activation of protein kinase C theta (PKCθ) and its downstream signaling molecules. BGE decreased T helper (Th)2 cytokines, serum IgE, mucus secretion, and iNOS expression in mice with allergic airway inflammation, thereby providing a protective effect. Moreover, BGE and its major ginsenosides inhibited the production of Th2 cytokines in PMA/Iono-stimulated EL4 cells. In EL4 cells, these outcomes were accompanied by the inactivation of PKCθ and its downstream transcription factors, such as nuclear factor of activated T cells (NFAT), nuclear factor kappa B (NF-κB), activator of transcription 6 (STAT6), and GATA binding protein 3 (GATA3), which are involved in allergic airway inflammation. BGE also inhibited the activation of PKCθ and the abovementioned transcriptional factors in the lung tissue of mice with allergic airway inflammation. These results highlight the potential of BGE as a useful therapeutic and preventative agent for allergic airway inflammatory diseases such as allergic asthma.

Verproside, the Most Active Ingredient in YPL-001 Isolated from Pseudolysimachion rotundum var. subintegrum, Decreases Inflammatory Response by Inhibiting PKCδ Activation in Human Lung Epithelial Cells.

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease which causes breathing problems. YPL-001, consisting of six iridoids, has potent inhibitory efficacy against COPD. Although YPL-001 has completed clinical trial phase 2a as a natural drug for COPD treatment, the most effective iridoid in YPL-001 and its mechanism for reducing airway inflammation remain unclear. To find an iridoid most effectively reducing airway inflammation, we examined the inhibitory effects of the six iridoids in YPL-001 on TNF or PMA-stimulated inflammation (IL-6, IL-8, or MUC5AC) in NCI-H292 cells. Here, we show that verproside among the six iridoids most strongly suppresses inflammation. Both TNF/NF-κB-induced MUC5AC expression and PMA/PKCδ/EGR-1-induced IL-6/-8 expression are successfully reduced by verproside. Verproside also shows anti-inflammatory effects on a broad range of airway stimulants in NCI-H292 cells. The inhibitory effect of verproside on the phosphorylation of PKC enzymes is specific to PKCδ. Finally, in vivo assay using the COPD-mouse model shows that verproside effectively reduces lung inflammation by suppressing PKCδ activation and mucus overproduction. Altogether, we propose YPL-001 and verproside as candidate drugs for treating inflammatory lung diseases that act by inhibiting PKCδ activation and its downstream pathways.

Diplacone Isolated from Paulownia tomentosa Mature Fruit Induces Ferroptosis-Mediated Cell Death through Mitochondrial Ca2+ Influx and Mitochondrial Permeability Transition.

The recently defined type of cell death ferroptosis has garnered significant attention as a potential new approach to cancer treatment owing to its more immunogenic nature when compared with apoptosis. Ferroptosis is characterized by the depletion of glutathione (GSH)/glutathione peroxidase-4 (GPx4) and iron-dependent lipid peroxidation. Diplacone (DP), a geranylated flavonoid compound found in Paulownia tomentosa fruit, has been identified to have anti-inflammatory and anti-radical activity. In this study, the potential anticancer activity of DP was explored against A549 human lung cancer cells. It was found that DP induced a form of cytotoxicity distinct from apoptosis, which was accompanied by extensive mitochondrial-derived cytoplasmic vacuoles. DP was also shown to increase mitochondrial Ca2+ influx, reactive oxygen species (ROS) production, and mitochondrial permeability transition (MPT) pore-opening. These changes led to decreases in mitochondrial membrane potential and DP-induced cell death. DP also induced lipid peroxidation and ATF3 expression, which are hallmarks of ferroptosis. The ferroptosis inhibitors ferrostatin-1 and liproxstatin-1 were effective in counteracting the DP-mediated ferroptosis-related features. Our results could contribute to the use of DP as a ferroptosis-inducing agent, enabling studies focusing on the relationship between ferroptosis and the immunogenic cell death of cancer cells.

Compound K ameliorates airway inflammation and mucus secretion through the regulation of PKC signaling in vitro and in vivo.

Background: Cigarette smoke (CS) is considered a principal cause of chronic obstructive pulmonary disease (COPD) and is associated with mucus hypersecretion and airway inflammation. Ginsenoside compound K (CK), a product of ginsenoside metabolism, has various biological activities. Studies on the effects of CK for the treatment of COPD and mucus hypersecretion, including the underlying signaling mechanism, have not yet been conducted. Methods: To study the protective effects and molecular mechanism of CK, phorbol 12-myristate 13-acetate (PMA)-induced human airway epithelial (NCI-H292) cells were used as a cellular model of airway inflammation. An experimental mouse COPD model was also established via CS inhalation and intranasal administration of lipopolysaccharide. Mucin 5AC (MUC5AC), monocyte chemoattractant protein-1, tumor necrosis factor-α (TNF-α), and interleukin-6 secretion, as well as elastase activity and reactive oxygen species production, were determined through enzyme-linked immunosorbent assay. Inflammatory cell influx and mucus secretion in mouse lung tissues were estimated using hematoxylin and eosin and periodic acid-schiff staining, respectively. PKCδ and its downstream signaling molecules were analyzed via western blotting. Results: CK prevented the secretion of MUC5AC and TNF-α in PMA-stimulated NCI-H292 cells and exhibited a protective effect in COPD mice via the suppression of inflammatory mediators and mucus secretion. These effects were accompanied by an inactivation of PKCδ and related signaling in vitro and in vivo. Conclusion: CK suppressed pulmonary inflammation and mucus secretion in COPD mouse model through PKC regulation, highlighting the compound's potential as a useful adjuvant in the prevention and treatment of COPD.

Black Ginseng Extract Suppresses Airway Inflammation Induced by Cigarette Smoke and Lipopolysaccharides In Vivo.

Cigarette smoke (CS) is a risk factor that can induce airway enlargement, airway obstruction, and airway mucus hypersecretion. Although studies have shown that Korean black ginseng extract (BGE) has potent anti-inflammatory and antioxidant activities, the CS-induced inflammatory responses and molecular mechanisms are yet to be examined. The aim of this study was to examine the effect of BGE on the airway inflammatory response and its molecular mechanisms, using CS/lipopolysaccharides (LPS)-exposed animals and PMA-stimulated human airway epithelial NCI-H292 cells. The results show that BGE inhibited the recruitment of immune cells and the release of inflammatory mediators, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6, monocyte chemoattractant protein (MCP)-1, elastase, and reactive oxygen species (ROS) in the airways of CS/LPS-exposed animals. BGE inhibited mucus secretion and the expression of Mucin 5AC (MUC5AC). Furthermore, BGE exhibited an anti-inflammatory effect by downregulating a signaling pathway mediated by transforming growth factor-ß-activated kinase (TAK) 1, an important protein that accelerates inflammation by cigarette smoke (CS). Overall, the findings show that BGE inhibits lung inflammation and mucus secretion by decreasing the activation of TAK1 both in human epithelial cells and in CS/LPS-exposed animals, and could be a potential adjuvant in the treatment and prevention of airway inflammatory diseases caused by airway irritants such as CS.

Daphnodorin C isolated from the stems of Daphne kiusiana Miquel attenuates airway inflammation in a mouse model of chronic obstructive pulmonary disease.

BACKGROUND: Since long-term or high-dose use of COPD medication causes adverse effects in patients with COPD, more effective and safer ways to manage COPD symptoms are required. Daphne kiusiana Miquel is a medicinal plant, but its anti-COPD efficacy was little studied. PURPOSE: We investigated the anti-COPD activity and molecular mechanism of action of active compounds isolated from D. kiusiana to find drug candidates for COPD. METHODS: We isolated seven compounds (1-7) in an ethyl acetate (EtOAc) fraction from D. kiusiana, and determined that seven compounds effectively control the inflammatory responsiveness in both PMA-stimulated lung epithelial cells (in vitro) and/or in COPD model mice using cigarette smoke- and lipopolysaccharides-exposed animals in vivo. RESULTS: We show that the ethyl acetate (EtOAc) fraction from D. kiusiana. suppresses inflammatory response in both PMA-stimulated human lung epithelial cells (in vitro) and COPD model mice (in vivo). The EtOAc fraction effectively suppresses various inflammatory responses, such as mucus secretion, ROS production, bronchial recruitment of inflammatory cells, and release of proinflammatory cytokines. Additionally, we isolated three compounds with anti-inflammatory efficacy from the EtOAc fraction, out of which daphnodorin C was the most effective. Finally, we demonstrated that daphnodorin C negatively regulates inflammatory gene expression by suppressing NF-κB and specific MAPK signaling pathways (JNK and p38) in vitro and in vivo. CONCLUSIONS: These results suggest that daphnodorin C could be a promising therapeutic alternative for managing COPD symptoms.

Transforming Growth Factor ß Inhibits MUC5AC Expression by Smad3/HDAC2 Complex Formation and NF-κB Deacetylation at K310 in NCI-H292 Cells.

Airway mucus secretion is an essential innate immune response for host protection. However, overproduction and hypersecretion of mucus, mainly composed of the gel- forming MUC5AC protein, are significant risk factors for patients with asthma and chronic obstructive pulmonary disease (COPD). The transforming growth factor ß (TGFß) signaling pathway negatively regulates MUC5AC expression; however, the underlying molecular mechanism is not fully understood. Here, we showed that TGFß significantly reduces the expression of MUC5AC mRNA and its protein in NCI-H292 cells, a human mucoepidermoid carcinoma cell line. This reduced MUC5AC expression was restored by a TGFß receptor inhibitor (SB431542), but not by the inhibition of NF-κB (BAY11-7082 or Triptolide) or PI3K (LY294002) activities. TGFß-activated Smad3 dose-dependently bound to MUC5AC promoter. Notably, TGFß-activated Smad3 recruited HDAC2 and facilitated nuclear translocation of HDAC2, thereby inducing the deacetylation of NF-κB at K310, which is essential for a reduction in NF-κB transcriptional activity. Both TGFß-induced nuclear translocation of Smad3/HDAC2 and deacetylation of NF-κB at K310 were suppressed by a Smad3 inhibitor (SIS3). These results suggest that the TGFß-activated Smad3/HDAC2 complex is an essential negative regulator for MUC5AC expression and an epigenetic regulator for NF-κB acetylation. Therefore, these results collectively suggest that modulation of the TGFß1/Smad3/HDAC2/NF-κB pathway axis can be a promising way to improve lung function as a treatment strategy for asthma and COPD.

Biflavonoid-rich fraction from Daphne pseudomezereum var. koreana Hamaya exerts anti-inflammatory effect in an experimental animal model of allergic asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Daphne pseudomezereum var. koreana Hamaya is distributed in the Gangwon-do of South Korea and is traditionally used to treat chronic inflammatory diseases, including rheumatoid arthritis. AIM OF THE STUDY: We investigated the anti-inflammatory effect of biflavonoid-rich fraction (BF) obtained from an extract of D. pseudomezereum leaves on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and mouse model of ovalbumin (OVA)-induced allergic asthma. MATERIALS AND METHODS: Neochamaejasmin B (NB) and chamaejasmin D (CD) were spectroscopically characterized as major components of BF obtained from the leaves of D. pseudomezereum. RAW264.7 cells pretreated with NB, CD and BF and activated by LPS (500 ng/ml) were used to assess the anti-inflammatory effects of these materials in vitro. To evaluate the protective effect of BF on allergic asthma, female BALB/c mice were sensitized to OVA by intraperitoneal (i.p.) injection and treated with BF by oral administration (15 or 30 mg/kg). RESULTS: Pretreatment with BF inhibited LPS-stimulated nitric oxide (NO), TNF-α and IL-6, and led to upregulation of heme oxygenase-1 (HO-1) in RAW264.7 macrophages. Orally administered BF significantly inhibited the recruitment of eosinophils and the production of IL-5, IL-6, IL-13 and MCP-1 as judged by the analysis of BALF from OVA-induced asthma animal model. BF also decreased the levels of IgE in the serum of asthmatic mice. BF suppressed the influx of inflammatory cells into nearby airways and the hypersecretion of mucus by the airway epithelium of asthmatic mice. In addition, the increase in Penh in asthmatic mice was reduced by BF administration. Furthermore, BF led to Nrf2 activation and HO-1 induction in the lungs of mice. CONCLUSIONS: These data have shown the anti-asthmatic effects of BF, and therefore we expect that BF may be a potential candidate as a natural drug/nutraceutical for the prevention and treatment of allergic asthma.

Longifolioside A inhibits TLR4-mediated inflammatory responses by blocking PKCδ activation in LPS-stimulated THP-1 macrophages.

Longifolioside A is an iridoid glucoside compound isolated from Pseudolysimachion rotundum var. subintegrum, which has been used in traditional herbal medicines to treat respiratory inflammatory diseases. Logifolioside A is a potent antioxidant; however, its underlying pharmacological mechanisms of action in inflammatory diseases are unknown. Here, we investigated the inhibitory effects of longifolioside A in lipopolysaccharide (LPS)-stimulated toll-like receptor 4 (TLR4) signal transduction systems using human THP-1 macrophages and HEK293 cells stably expressing human TLR4 protein (293/HA-hTLR4). Longifolioside A significantly reduced the release of inflammatory cytokines such as interleukin (IL)-6, -8, and tumor necrosis factor (TNF)-α in LPS-stimulated THP-1 macrophages. Furthermore, longifolioside A inhibited the expression of inflammatory mediator genes such as inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 that produce nitric oxide (NO) and prostaglandin E2 (PGE2), respectively. Longifolioside A suppressed the phosphorylation of PKCδ, IRAK4, IKKα/ß, IκBα, and mitogen-activated protein (MAP) kinases (ERK 1/2 and JNK, but not p38), thereby inactivating the nuclear localization of NF-κB and AP-1, and thus decreasing the expression of inflammatory response genes. Notably, longifolioside A disrupted the interaction between human TLR4 and the TIR domain-containing adaptor protein (TIRAP), an early step during TLR4 activation, thereby reducing IL-8 secretion in 293/HA-hTLR4 cells. This inhibitory effect was comparable to that of TAK-242 (a TLR4 inhibitor, or resatorvid). Our results indicate that longifolioside A prevents inflammatory response by suppressing TLR4 activation required for NF-κB and AP-1 activation.