Britanin Suppresses IgE/Ag-Induced Mast Cell Activation by Inhibiting the Syk Pathway

Britanin - a beacon of hope against gastrointestinal tumors?

Britanin is a bioactive sesquiterpene lactone known for its potent anti-inflammatory and anti-oxidant properties. It also exhibits significant anti-tumor activity, suppressing tumor growth in vitro and in vivo. The current body of research on Britanin includes thirty papers predominantly related to neoplasms, the majority of which are gastrointestinal tumors that have not been summarized before. To drive academic debate, the present paper reviews the available research on Britanin in gastrointestinal tumors. It also outlines novel research directions using data not directly concerned with the digestive system, but which could be adopted in future gastrointestinal research. Britanin was found to counteract liver, colorectal, pancreatic, and gastric tumors, by regulating proliferation, apoptosis, autophagy, immune response, migration, and angiogenesis. As confirmed in pancreatic, gastric, and liver cancer, its most commonly noted molecular effects include nuclear factor kappa B and B-cell lymphoma 2 downregulation, as well as Bcl-2-associated X protein upregulation. Moreover, it has been found to induce the Akt kinase and Forkhead box O1 axis, activate the AMP-activated protein kinase pathway, elevate interleukin-2 and peroxisome proliferator-activated receptor-γ levels, reduce interleukin-10, as well as downregulate matrix metalloproteinase-9, Twist family bHLH transcription factor 1, and cyclooxygenase-2. It also inhibits Myc-HIF1α interaction and programmed death ligand 1 transcription by interrupting the Ras/ RAF/MEK/ERK pathway and mTOR/P70S6K/4EBP1 signaling. Future research should aim to unravel the link between Britanin and acetylcholinesterase, mast cells, osteolysis, and ischemia, as compelling data have been provided by studies outside the gastrointestinal context. Since the cytotoxicity of Britanin on noncancerous cells is significantly lower than that on tumor cells, while still being effective against the latter, further in-depth studies with the use of animal models are merited. The compound exhibits pleiotropic biological activity and offers considerable promise as an anti-cancer agent, which may address the current paucity of treatment options and high mortality rate among patients with gastrointestinal tumors.

Britanin inhibits titanium wear particle‑induced osteolysis and osteoclastogenesis

Wear particle‑induced osteolysis is a serious complication that occurs in individuals with titanium (Ti)‑based implants following long‑term usage due to loosening of the implants. The control of excessive osteoclast differentiation and inflammation is essential for protecting against wear particle‑induced osteolysis. The present study evaluated the effect of britanin, a pseudoguaianolide sesquiterpene isolated from Inula japonica, on osteoclastogenesis in vitro and Ti particle‑induced osteolysis in vivo. The effect of britanin was examined in the osteoclastogenesis of mouse bone marrow‑derived macrophages (BMMs) using TRAP staining, RT‑PCR, western blotting and immunocytochemistry. The protective effect of britanin was examined in a mouse calvarial osteolysis model and evaluated using micro‑CT and histomorphometry. Britanin inhibited osteoclast differentiation and F‑actin ring formation in the presence of macrophage colony‑stimulating factor and receptor activator of nuclear factor kB ligand in BMMs. The expression of osteoclast‑specific marker genes, including tartrate‑resistant acid phosphatase, cathepsin K, dendritic cell‑specific transmembrane protein, matrix metallopeptidase 9 and nuclear factor of activated T‑cells cytoplasmic 1, in the BMMs was significantly reduced by britanin. In addition, britanin reduced the expression of B lymphocyte‑induced maturation protein‑1, which is a transcriptional repressor of negative osteoclastogenesis regulators, including interferon regulatory factor‑8 and B‑cell lymphoma 6. Conversely, britanin increased the expression levels of anti‑oxidative stress genes, namely nuclear factor erythroid‑2‑related factor 2, NAD(P)H quinone oxidoreductase 1 and heme oxygenase 1 in the BMMs. Furthermore, the administration of britanin significantly reduced osteolysis in a Ti particle‑induced calvarial osteolysis mouse model. Based on these findings, it is suggested that britanin may be a potential therapeutic agent for wear particle‑induced osteolysis and osteoclast‑associated disease.

The Complexity of Sesquiterpene Chemistry Dictates Its Pleiotropic Biologic Effects on Inflammation

Sesquiterpenes (SQs) are volatile compounds made by plants, insects, and marine organisms. SQ have a large range of biological properties and are potent inhibitors and modulators of inflammation, targeting specific components of the nuclear factor-kappaB (NF-κB) signaling pathway and nitric oxide (NO) generation. Because SQs can be isolated from over 1600 genera and 2500 species grown worldwide, they are an attractive source of phytochemical therapeutics. The chemical structure and biosynthesis of SQs is complex, and the SQ scaffold represents extraordinary structural variety consisting of both acyclic and cyclic (mono, bi, tri, and tetracyclic) compounds. These structures can be decorated with a diverse range of functional groups and substituents, generating many stereospecific configurations. In this review, the effect of SQs on inflammation will be discussed in the context of their complex chemistry. Because inflammation is a multifactorial process, we focus on specific aspects of inflammation: the inhibition of NF-kB signaling, disruption of NO production and modulation of dendritic cells, mast cells, and monocytes. Although the molecular targets of SQs are varied, we discuss how these pathways may mediate the effects of SQs on inflammation.

A TCM formula VYAC ameliorates DNCB-induced atopic dermatitis via blocking mast cell degranulation and suppressing NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

A Traditional Chinese Medicine (TCM) formula (VYAC) consists of three herbs including Viola yedoensis Makino, herb (Violaceae, Viola), Sophora flavescens Aiton, root (Fabaceae, Sophora) and Dictamnus dasycarpus Turcz, root and rhizome (Rutaceae, Dictamnus), has been traditionally prescribed to treat various skin diseases in clinic.

AIM OF THE STUDY

This study aims to investigate the therapeutic effects of VYAC on the 2,4-dinitrobenzene (DNCB) induced atopic dermatitis (AD)-like mice and to explore the underlying mechanisms.

MATERIALS AND METHODS

VYAC was extracted with 70 % aqueous ethanol and lyophilized powder was used. AD-like mice were challenged by DNCB, VYAC (150 and 300 mg/kg) were oral administration daily from day 7 to day 28. At the end of experiment, the clinical scores were recorded, serum and skin in the dorsal were isolated to evaluate the therapeutic effects of VYAC. RBL-2H3 cells were stimulated with C48/80 for degranulation and plasmids expressing constitutively active form of Syk (Silence or overexpression) were transfected into RBL-2H3 cells to explore the underlying mechanisms in vitro.

RESULTS

VYAC significantly ameliorated the cardinal symptoms in the DNCB-induced AD-like mice by repairing the skin barrier function, inhibiting mast cells infiltration, restraining the serum IgE and histamine release and decreasing TNF-α, IL-4 as well as Syk mRNA level in dorsal skin and alleviating inflammation. Besides, VYAC significantly blocked RBL-2H3 cells degranulation, reduced β-hexosaminidase and histamine release, and suppressed NF-κB pathway. What's more, the degranulation of RBL-2H3 was reduced after Syk silence and increased after Syk overexpression.

CONCLUSION

Our findings clearly suggested that VYAC treat AD through inhibiting the inflammatory mediator productions and blocking mast cell degranulation via suppressing Syk mediated NF-κB pathway.

1β-Hydroxyalantolactone from Inulae Flos alleviated the progression of pulmonary fibrosis via inhibiting JNK/FOXO1/NF-κB pathway

Inulae Flos was widely distributed throughout Europe, Africa, and Asia, and was commonly used as a folk medicine in clinic for treating various respiratory diseases, including cough, asthma, bronchitis, pulmonary fibrosis, and pneumonia. However, the ingredients responsible for the pharmacology effects of I. Flos and the underlying mechanisms remain unclear. In this study, the effects of 16 known sesquiterpene lactones and flavonoids from I. Flos on TGF-β1-induced fibroblast activation were assessed by phenotypic high-content screening. Among those sixteen compounds, 1β-hydroxy alantolactone (HAL), the main characteristic sesquiterpene lactone from I. Flos, exhibited remarkable inhibitory activity. The further studies showed that HAL significantly inhibited the proliferation and induced the apoptosis of human fibroblast cell lines HELF and MRC-5 in a concentration-dependent manner. It also reduced intracellular ROS production, suppressed the mRNA expressions of E-cad, TGF-β1, Smad3, Col I, α-SMA and TNF-α, and downregulated protein expressions of α-SMA and F-actin. Furthermore, HAL significantly reduced the levels of HA, LN, PC-III and IV-C in serum, TNF-α and IL-6 in BALF, and TGF-β1, HYP and Col I in lung tissues of bleomycin (BLM)-treated rats. HAL significantly downregulated the expressions of p-JNK, FOXO1, p-p65, α-SMA, p-smad3 and Col I but upregulated p-FOXO1, which could be reversed by JNK agonist anisomycin. These results demonstrated that HAL induced the apoptosis of lung fibroblast cells activated by TGF-β1 and improved BLM-induced lung fibrosis in rats via inhibiting JNK/FOXO1/NF-κB pathway.

A review of the botany, traditional uses, phytochemistry, and pharmacology of the Flos Inulae

ETHNOPHARMACOLOGICAL RELEVANCE

Plants of the genus Inula have long been used as an ethnomedicine in Asia, Europe, and North America for its high medicinal value and health benefits. Inula japonica Thunb. (I. japonica) and Inula britanica L. (I. britanica) are included in Chinese Pharmacopoeia (2020 edition) as the traditional Chinese medicine Flos inulae (FI). In TCM, FI tastes bitter, pungent, and salt, with warm nature and has the functions of water removal, reduction in nausea, and prevention of vomiting and is often used for cold-related coughs, sputum, wheezing coughs, vomiting, belching and other related diseases. In addition, Inula japonica Thunb is used as a botanical medicine in Korea and Inula britannica L. is also used as a traditional plant medicine in Iran.

AIM OF THE STUDY

This paper collects the relevant research literature (1970-2021) and provides a systematic summary of the botany, ethnopharmacology, processing, phytochemistry, pharmacology, toxicity, analytical methods and quality control of FI to explore its potential and expand its scope for better clinical application.

MATERIALS AND METHODS

Information on Inula japonica Thunb. and Inula britanica L. was collected from scientific databases (1970-2021), including Google Scholar, Baidu Scholar, Springer, PubMed, CNKI and Wan Fang DATA. Information was also collected from classic books of Chinese herbal medicine and Ph.D. and M.Sc. theses.

RESULTS

More than 200 chemical compounds have been isolated from Inula japonica Thunb. and Inula britanica L., including sesquiterpenes, flavonoids, volatile oils, triterpenoids, diterpenoid glycosides, monoterpenoids, polysaccharides, steroid and small molecule acids. Based on a wide variety of chemically active ingredients, FI has a wide range of pharmacological effects. Modern pharmacological research has proven that the pharmacological effects of FI include anti-inflammatory, antitumor, antioxidant, antiallergy, antidiabetic, blood lipid reduction, skin whitening, liver protection, anticonstipation, and antinociceptive effects.

CONCLUSIONS

FI is a very important traditional Chinese herbal medicine with anti-inflammatory antitumor, antioxidant, antiallergy, antidiabetic and other pharmacological effects that can treat a variety of related diseases. This paper summarizes the botany, ethnopharmacology, processing, phytochemistry, pharmacology, toxicity, analytical methods, and quality control of FI. However, the research on the processing, toxicity and quality control of FI is currently too shallow, especially concerning the relationship between the changes in active components before and after processing and the changes in its pharmacological action, which remains unclear. There are few toxicity experiments conducted with FI, so it is impossible to evaluate the safety of FI objectively and impartially. There are also few studies on the material basis and doses of FI causing toxicity and side effects, and more in-depth and concrete researches should be carried out in the future regarding these aspects. Furthermore, to ensure effective and safe clinical medication, we should also pay attention to the mixed use of FI in various regions of China to control the quality of the FI plant.

The Antitumor Effects of Britanin on Hepatocellular Carcinoma Cells and its Real-Time Evaluation by In Vivo Bioluminescence Imaging

BACKGROUND

Hepatocellular carcinoma is cancer with many new cases and the highest mortality rate. Chemotherapy is the most commonly used method for the clinical treatment of hepatocellular carcinoma. Natural products have become clinically important chemotherapeutic drugs due to their great potential for pharmacological development. Many sesquiterpene lactone compounds have been proven to have antitumor effects on hepatocellular carcinoma.

OBJECTIVE

Britanin is a sesquiterpene lactone compound that can be considered for the treatment of hepatocellular carcinoma. The present study aimed to investigate the antitumor effect of britanin.

METHODS

BEL 7402 and HepG2 cells were used to study the cytotoxicity and antitumor effects of britanin. Preliminary studies on the nuclear factor kappa B pathway were conducted by western blot analysis. A BEL 7402-luc subcutaneous tumor model was established for the in vivo antitumor studies of britanin. In vivo bioluminescence imaging was conducted to monitor changes in tumor size.

RESULTS

The results of the cytotoxicity analysis showed that the IC50 values for britanin in BEL 7402 and HepG2 cells were 2.702μM and 6.006μM, respectively. The results of the colony formation demonstrated that the number of cells in a colony was reduced significantly after britanin treatment. And the results of transwell migration assays showed that the migration ability of tumor cells was significantly weakened after treatment with britanin. Tumor size measurements and staining results showed that tumor size was inhibited after britanin treatment. The western blot analysis results showed the inhibition of p65 protein expression and reduced the ratio of Bcl-2/Bax after treatment.

CONCLUSION

A series of in vitro and in vivo experiments demonstrated that britanin had good antitumor effects and provided an option for hepatocellular carcinoma treatment.

Syk-Targeted, a New 3-Arylbenzofuran Derivative EAPP-2 Blocks Airway Inflammation of Asthma-COPD Overlap in vivo and in vitro

Introduction

Asthma–chronic obstructive pulmonary (COPD) overlap (ACO) coexists with asthma and COPD syndrome characteristics, with more frequent exacerbations, heavier disease burden, higher medical utilization, and even lower quality of life. However, the ACO standard medications supported by evidence-based medicine have not yet appeared.

Methods

By using an ACO mouse model established previously and LPS-stimulated RAW264.7 macrophages in vitro, a potential therapeutic candidate, EAPP-2, was screened from derivatives of 3-arylbenzofuran, and its effect and mechanism on ACO inflammation were evaluated.

Results

EAPP-2 significantly alleviated airway inflammation in ACO mice and also inhibited the inflammatory reactions in LPS-induced RAW264.7 macrophages in vitro. Furthermore, EAPP-2 significantly inhibited the expression and phosphorylation of spleen tyrosine kinase (Syk), a common target regulating both eosinophils and neutrophils inflammation. In addition to this, EAPP-2 significantly down-regulates the expression of NF-κB, p-NF-κB, and NLRP3 in vivo and in vitro. Moreover, by using specific inhibitors in vitro, it was validated that EAPP-2 targeted on Syk and then regulated its downstream NF-κB and NLRP3.

Conclusion

EAPP-2 is shown to be a potentially useful therapeutic candidate for ACO, and its mechanism is at least partially achieved by targeting on Syk and then inhibiting NF-κB or NLRP3. Moreover, this study suggests that Syk may be a potentially effective target for ACO therapy.

Brusatol Derivative-34 Attenuates Allergic Airway Inflammation Via Inhibition of the Spleen Tyrosine Kinase Pathway

Brusatol derivative-34 (Bru-34), a derivative of brusatol, has been shown significantly anti-inflammatory activity in mice in our previously work. However, to our knowledge, there were very limited studies on how Bru-34 affected airway inflammation. Thus, in this present study, the effects and potential mechanisms of Bru-34 on allergic airway inflammation were examined both in vivo and in vitro. The results showed that Bru-34 attenuated the allergic airway inflammation in mice, with significant decreasing of the inflammatory cells and mediators in bronchoalveolar lavage fluids and attenuation of the histopathological alterations in the lung tissues. In addition, Bru-34 significantly inhibited the release of inflammatory cytokines in antigen induced rat basophilic leukemia -2H3 (RBL-2H3) cells. What’s more, Bru-34 significantly decreased the expression of spleen tyrosine kinase (Syk), p-Syk, cytoplasmic phospholipase A2 (cPLA2), p-cPLA2, nuclear factor-κB (NF-κB) and p-NF-κB both in allergic mice lung tissue and antigen induced RBL-2H3 cells. Furthermore, the collaborative effects of Bru-34 with inhibitors against Syk, cPLA2, and NF-κB, showed that Syk was an important target of Bru-34, and cPLA2 and NF-κB played important roles in the coordinated inflammatory response. In conclusion, Bru-34 could significantly modulate the allergic airway inflammation, and its potential mechanism was revealed at least partially via down-regulating of Syk-cPLA2 -NF-κB signaling.

Britanin Exhibits Potential Inhibitory Activity on Human Prostate Cancer Cell Lines Through PI3K/Akt/NF-κB Signaling Pathways

Britanin, a natural pseudoguaiacane sesquiterpene lactone, has significant antioxidant and anti-inflammatory activity, but little is known about its tumor inhibitory activity and the underlying mechanism. Here, we demonstrated in vitro and in vivo that britanin inhibited the growth of human prostate cancer cell lines (PC-3, PC-3-LUC, and DU-145). Through in vitro study, the results showed that britanin significantly decreased cell proliferation, migration, and motility. The moderate toxicity of britanin was determined with an acute toxicity study. A luciferase-labeled animal tumor xenograft model and bioluminescence imaging were applied, combining with biological validation for assessing the tumor progression. In vivo results demonstrated that britanin inhibited the growth of PC-3-LUC. The interleukin-2 level in mice was upregulated by britanin, which indicated that britanin induced antitumor immune activation. In addition, britanin downregulated the expression of nuclear factor (NF)-κB p105/p50, pp65, IκBα, pIκBα, phosphoinositide 3-kinase, pPI3k, Akt (protein kinase B, PKB), and pAkt proteins and upregulated expression of Bax. We discovered that britanin inhibits the growth of prostate cancer cells both in vitro and in vivo by regulating PI3K/Akt/NF-κB-related proteins and activating immunity. These findings shed light on the development of britanin as a promising agent for prostate cancer therapy.

A novel natural product, britanin, inhibits tumor growth of pancreatic cancer by suppressing nuclear factor-κB activation

Pancreatic cancer has a high mortality rate and poor prognosis. The development of novel medicines for pancreatic cancer therapy is urgently need. Britanin is a bioactive sesquiterpene lactone, that exhibits excellent anti-inflammatory and antioxidant effects. However, the potential anti-tumour activity of britanin is also considerable. Hence, in this study, the in vitro and in vivo anti-pancreatic cancer effects of britanin were investigated. Several pancreatic cancer cell lines were applied to evaluate inhibition of proliferation, migration and NF-κB pathway in vitro. Then in vivo toxicity of britanin was evaluated in BALB/c mice. The in vivo inhibitory effects of britanin were investigated by bioluminescence imaging, traditional methods and histological analysis in a pancreatic cancer xenograft mouse model. The results showed that britanin exhibited effective anti-tumour actions both in vitro and in vivo. The IC₅₀ values in PANC-1, BxPC-3 and MIA CaPa-2 cell lines were 1.348, 3.367 and 3.104 μmol/L, respectively, and cell proliferation and migration were significantly inhibited by britanin treatment. Western blotting demonstrated that NF-κB family proteins, such as P50, P65, and P-P65 were affected by britanin treatment. It is worth noting that the P-P65 protein, which regulates the expression of multiple factors downstream, was significantly decreased in britanin treated group. In vivo experiments verified that britanin could suppress the tumour progression in a pancreatic cancer xenograft mouse model, while the compound did not exhibit intolerable toxicity. In conclusion, britanin has remarkable potential treatment effects against pancreatic cancer, and it could be developed as a new agent for pancreatic cancer chemotherapy.

In vivo antitumour activity of Britanin against gastric cancer through nuclear factor-κB-mediated immune response

OBJECTIVES

Britanin was explored for the antitumour effect on gastric cancer, which is a sesquiterpene lactone (SL) extracted from Inula japonica.

METHODS

In the present study, cell viability assays were performed to evaluate the antiproliferation effect of Britanin on gastric cancer cells. Tumour development in BGC-823 cell-bearing nude mice was monitored in real-time after Britanin treatment via a bioluminescent imaging method. Western blotting analysis and enzyme-linked immunosorbent assays detected proteins associated with the nuclear factor (NF)-κB signalling pathway.

KEY FINDINGS

Britanin can suppress the proliferation of gastric cancer cells in vitro and the growth of tumours in vivo. In the treatment group, decreased levels of p65 and phosphorylated (p)-p65 were observed. This indicated that NF-κB plays an important role in the antitumour effect of Britanin. Furthermore, considering the additional role of NF-κB in the immune system, the levels of the downstream molecules interleukin (IL)-2 and the cytokine IL-10 were subsequently determined in vivo. An increase in the IL-2 level and a decrease in the IL-10 level indicated that Britanin elicited an enhanced immune response.

CONCLUSIONS

Britanin may be a promising candidate for gastric cancer chemotherapy, and its anticancer effect likely depends on an NF-κB-mediated immune response.

Amurensin H, a Derivative From Resveratrol, Ameliorates Lipopolysaccharide/Cigarette Smoke-Induced Airway Inflammation by Blocking the Syk/NF-κB Pathway

Amurensin H, a resveratrol dimer derived from Vitis amurensis Rupr, has several biological effects, including anti-inflammatory and antioxidant activities. Studies have found that amurensin H attenuated asthma-like allergic airway inflammation. However, its protective activity on chronic obstructive pulmonary disease (COPD) airway inflammation is not fully explored. The present study used a lipopolysaccharide (LPS)/cigarette smoke-induced mice model and an LPS-stimulated THP-1-derived macrophages model to measure the lung tissue's morphology changes. The results showed that amurensin H ameliorated the histological inflammatory alterations in the lung tissues, leading to a decrease in the expression of interleukin 6 (IL-6), IL-17A, tumor necrosis factor α (TNF-α), and interferon γ in bronchoalveolar lavage fluid. Amurensin H also significantly inhibited the release of IL-1β, IL-6, IL-8, and TNF-α in LPS-stimulated THP-1-derived macrophages. Furthermore, amurensin H markedly inhibited the expressions of p-Syk, nuclear factor κB (NF-κB), and p-NF-κB both in vivo and in vitro. Results from cotreatment with Syk inhibitor BAY61-3606 and NF-κB inhibitor BAY11-7082 in vitro revealed that amurensin H's protective effect against airway inflammation could be due partly to the inhibition of the Syk/NF-κB pathway. These findings suggest that amurensin H shows therapeutic effects on COPD airway inflammation, and inhibiting the Syk/NF-κB pathway might be part of its underlying mechanisms.

Britanin attenuates ovalbumin-induced airway inflammation in a murine asthma model

We previously demonstrated the alleviation of ovalbumin (OVA)-induced airway inflammation by Inulae flos. In the present study, the effects of britanin, a sesquiterpene compound isolated from Inulae flos, were evaluated in an in vivo animal model for anti-asthma activity through observation of airway hyperresponsiveness (AHR), eosinophil recruitment, Th2 cytokine and IgE levels, and lung histopathology. Britanin administration effectively reduced AHR induced by aerosolized methacholine, airway eosinophilia, Th2 cytokines in bronchoalveolar lavage fluids and the supernatant of cultured splenocytes compared with OVA-induced mice. Histological studies showed that increased inflammatory cell infiltration and mucus secretion were reduced by britanin administration. Thus, britanin may have therapeutic potential for treating allergic asthma.

KOTMIN13, a Korean herbal medicine alleviates allergic inflammation in vivo and in vitro

Background

The ethanol extract of KOTMIN13, composed of Inula japonica Flowers, Trichosanthes kirilowii Semen, Peucedanum praeruptorum Radix, and Allium macrostemon Bulbs, was investigated for its anti-asthmatic and anti-allergic activities.

Methods

The anti-asthmatic effects of KOTMIN13 were evaluated on ovalbumin (OVA)-induced murine asthma model. Anti-allergic properties of KOTMIN13 in bone-marrow derived mast cells (BMMC) and passive cutaneous anaphylaxis (PCA) in vivo were also examined.

Results

In asthma model, KOTMIN13 effectively suppressed airway hyperresponsiveness induced by aerosolized methacholine when compared to the levels of OVA-induced mice. KOTMIN13 treatment reduced the total leukocytes, eosinophil percentage, and Th2 cytokines in the bronchoalveolar lavage fluids in OVA-induced mice. The increased levels of eotaxin and Th2 cytokines in the lung as well as serum IgE were decreased by KOTMIN13. The histological analysis shows that the increased inflammatory cell infiltration and mucus secretion were also reduced. In addition, the degranulation and leukotriene C₄ production were inhibited in BMMC with IC₅₀ values of 3.9 μg/ml and 1.7 μg/ml, respectively. Furthermore, KOTMIN13 treatment attenuated mast-mediated PCA reaction.

Conclusions

These results demonstrate that KOTMIN13 has anti-asthmatic and anti-allergic effects in vivo and in vitro models.

Imperatorin Suppresses Degranulation and Eicosanoid Generation in Activated Bone Marrow-Derived Mast Cells

Imperatorin has been known to exert many biological functions including anti-inflammatory activity. In this study, we investigated the inhibitory effects of imperatorin on the production of inflammatory mediators in mouse bone marrow-derived mast cells (BMMC). Imperatorin inhibited degranulation and the generation of eicosanoids (leukotriene C4 (LTC4) and prostaglandin D2 (PGD2)) in IgE/antigen (Ag)-stimulated BMMC. To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC. Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent LTC4 and cyclooxygenase-2-dependent PGD2 through the inhibition of intracellular calcium influx/phospholipase Cγ1, cytosolic phospholipase A2/mitogen-activated protein kinases and/or nuclear factor-κB pathways in BMMC. These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation.

15,16-Dihydrotanshinone I suppresses IgE-Ag stimulated mouse bone marrow-derived mast cell activation by inhibiting Syk kinase

ETHNOPHARMACOLOGICAL RELEVANCE

15,16-Dihydrotanshinone I (DHT-I), isolated from the dried root of Salvia miltiorrhiza Bung, which is traditionally used to treat cardiovascular and inflammatory diseases agent in Chinese medicine. DHT-I has been reported to have a broad range of biological activities, including antibacterial activity, and has been used to treat circulatory disorders, hepatitis, inflammation, cancer, and neurodegenerative diseases.

AIM OF THE STUDY

The aim of this study was to evaluate the anti-allergic inflammatory effects of DHT-I on degranulation and on the generation of eicosanoids, such as, prostaglandin D2 (PGD2) and leukotriene C4 (LTC4), in IgE/Ag-stimulated bone marrow-derived mast cells (BMMCs).

MATERIALS AND METHODS

The anti-allergic inflammatory activity of DHT-I was evaluated using BMMCs. The effects of DHT-I on mast cell activation were investigated by following degranulation and eicosanoid generation using ELISA and immunoblotting and immunoprecipitation techniques.

RESULTS

DHT-I at a concentration of 20μM markedly inhibited degranulation and the generation of PGD2 and LTC4 in IgE/Ag-stimulated BMMCs (about 90% inhibitions, respectively). Analyses of FcεRI-mediated signaling pathways demonstrated that DHT-I inhibited the phosphorylations of spleen tyrosine kinase (Syk) and linker for activation of T cells (LAT), and inhibited downstream signaling process, including [Ca(2+)]i mobilization induced by the phosphorylation of phospholipase Cγ1 (PLCγ1), and the activations of mitogen-activated protein kinases (MAPKs) and the Akt-nuclear factor-κB (NF-κB) pathway.

CONCLUSIONS

DHT-1 inhibits the release of allergic inflammatory mediators from IgE/Ag-stimulated mast cells by suppressing a FcεRI-mediated Syk-dependent signal pathway. This result suggests DHT-I offers a novel developmental basis for drugs targeting allergic inflammatory diseases.

An essential role of NAD(P)H oxidase 2 in UVA-induced calcium oscillations in mast cells

Solar UVA radiation (320-400 nm) is known to have immunomodulatory effects, but the detailed mechanisms involved are not fully elucidated. UVA irradiation has been shown to induce calcium oscillations in rat peritoneal mast cells due to NAD(P)H oxidase (NOX) activation, but the specific NOX isoforms have not been identified. In the present work effects of UVA irradiation were investigated in isolated rat peritoneal mast cells, in cultured rat mast cell line RBL-2H3, and in mouse bone marrow-derived mast cells (BMMC). It was found that UVA irradiation by alternate 340/380 nm (3.2-5.6 μW cm(-2)) or by LED (380 nm, 80 μW cm(-2)) induced calcium oscillations in isolated rat peritoneal mast cells, in RBL-2H3, and in BMMC. Such UVA-induced calcium oscillations resembled closely those induced by surface IgE receptor (FcεRI) activation. It was found that RBL-2H3 expressed high levels of gp91(phox) (NOX2), p22(phox), p67(phox), p47(phox), p40(phox), Rac1, Rac2, moderate levels of DUOX2, but did not express NOX1, NOX3, NOX4, or DUOX1. The specific cellular localizations of gp91(phox) (NOX2), p22(phox), p47(phox), p67(phox), p40(phox) and Rac1/2 were confirmed by immunocytochemistry. UVA-induced reactive oxygen species (ROS) production in RBL-2H3 was completely suppressed by the NOX inhibitor diphenyleneiodonium chloride (DPI) or by the antioxidant N-acetyl-l-cysteine (NAC). siRNA suppression of gp91(phox) (NOX2), p22(phox) and p47(phox) expression inhibited markedly UVA-induced calcium oscillations, ROS and IL-6/LTC4 production in RBL-2H3. Taken together these data indicate that NOX2 plays an essential role in UVA irradiation-induced calcium oscillations, ROS and mediator production in mast cells.