Molecular and cellular pruritus mechanisms in the host skin.

Pruritus, also known as itching, is a complex sensation that involves the activation of specific physiological and cellular receptors. The skin is innervated with sensory nerves as well as some receptors for various sensations, and its immune system has prominent neurological connections. Sensory neurons have a considerable impact on the sensation of itching. However, immune cells also play a role in this process, as they release pruritogens. Disruption of the dermal barrier activates an immune response, initiating a series of chemical, physical, and cellular reactions. These reactions involve various cell types, including keratinocytes, as well as immune cells involved in innate and adaptive immunity. Collective activation of these immune responses confers protection against potential pathogens. Thus, understanding the molecular and cellular mechanisms that contribute to pruritus in host skin is crucial for the advancement of effective treatment approaches. This review provides a comprehensive analysis of the present knowledge concerning the molecular and cellular mechanisms underlying itching signaling in the skin. Additionally, this review explored the integration of these mechanisms with the broader context of itch mediators and the expression of their receptors in the skin.

A single fluorescent probe to examine the dynamics of mitochondria-lysosome interplay and extracellular vesicle role in ferroptosis.

Ferroptosis is a non-apoptotic form of cell death characterized by iron-dependent lipid peroxidation and glutathione (GSH) depletion. Despite recent advances, challenges remain in understanding the bidirectional interactions or interplay between organelles during ferroptosis. In this study, we aimed to understand the interplay between mitochondria (Mito) and lysosomes (Lyso) in cell homeostasis and ferroptosis. For this purpose, we designed a single fluorescent probe that marks GSH in Mito and hypochlorous acid (HOCl) in Lyso with two distinct emissions. Using this dual-targeted single fluorescent probe (9-morphorino pyronine), we detected Mito-Lyso interplay in ferroptosis. We disclosed differences in Mito-Lyso interplay depending on the induction of ferroptosis. Although erastin treatment decreased GSH, RSL3 triggered a HOCl burst, and FIN56- and FINO2-induced ferroptosis increased GSH and HOCl. Additionally, we showed that only extracellular vesicles generated during erastin-induced ferroptosis could spontaneously move and dock to neighboring cells, resulting in accelerated cell death.

Notch1 signaling contributes to TLR4-triggered NF-κB activation in macrophages.

Macrophages substantially influence the development, progression, and complications of inflammation-driven diseases. Although numerous studies support the critical role of Notch signaling in most inflammatory diseases, there is limited data on the role of Notch signaling in TLR4-induced macrophage activation and interaction of Notch signaling with other signaling pathways in macrophages during inflammation, such as the NF-κB pathway. This study confirmed that stimulation with lipopolysaccharide (LPS), a TLR4 ligand, upregulated Notch1 expression in monocyte/macrophage-like RAW264.7 cells and bone marrow-derived macrophages (BMDMs). LPS also induced increased mRNA expression of Notch target genes Notch1 and Hes1 in macrophages, suggesting that TLR4 signaling enhances activation of the Notch pathway. The upregulation of Notch1, Notch1 intracellular domain (NICD), and Hes1 proteins by LPS treatment was inhibited by DAPT, a Notch1 inhibitor. Additionally, the increased TNF-α, IL-6, and IL-1ß expression induced by LPS was inhibited by DAPT and rescued by jagged1, a Notch1 ligand. Furthermore, suppression of Notch signaling by DAPT upregulated Cylindromatosis (CYLD) expression but downregulated TRAF6 expression, IκB kinase (IKK) α/ß phosphorylation, and subsequently, phosphorylation and degradation of IκB-α, indicating that DAPT inhibited NF-κB activation triggered by TLR-4. Interestingly, DAPT did not inhibit the increased MyD88 expression induced by LPS. Our study findings demonstrate that macrophage stimulation via the TLR4 signaling cascade triggers activation of Notch1 signaling, which regulates the expression patterns of genes involved in pro-inflammatory responses by activating NF-κB. This effect may be dependent on the CYLD-TRAF6-IKK pathway. Thus, Notch1 signaling may provide a therapeutic target against infectious and inflammation-driven diseases.

Dihydroartemisinin Alleviates Imiquimod-Induced Psoriasis-like Skin Lesion in Mice Involving Modulation of IL-23/Th17 Axis.

Background: Psoriasis is a T help 17 (Th17) cell-mediated chronic inflammatory skin disease. Recent studies have shown that dihydroartemisinin (DHA) can significantly reduce experimental autoimmune encephalomyelitis and rheumatoid arthritis by regulating Th17 cells. Objective: To verify whether DHA can improve the symptoms of psoriasis and to further explore the possible mechanism. Methods: The efficiency of DHA was preliminary detected on human keratinocytes (HaCaT) cells in psoriatic condition. Then, imiquimod-induced psoriasis-like model in BALB/c mice was established to evaluate the effects of DHA in vivo. Results: Under the stimulation of tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), DHA inhibited the proliferation of HaCaT cells and significantly affected the mRNA expression levels of IFN-γ, interleukin (IL), IL-17A and IL-23. DHA treatment reduced the severity of psoriasis-like skin and resulted in less infiltration of immune cells in skin lesions. DHA restored the expression of IFN-γ, IL-17A, and IL-23 in skins, as well as a decrease of cytokines and chemokines in skin supernatant. DHA also altered the cellular composition in the spleen, which is the makeup of the T cells, dendritic cells (DCs), and macrophages. DHA recovered Th17-related profile with decreased frequency of IL-17+CD4+T cells from splenocyte of mice. Furthermore, DHA also inhibited the concentration of IL-17 from Th17 cells and the expression of Th17 cell-related transcription factors retinoid-related orphan receptor-gamma t (ROR-γt) in vitro. In addition, phosphorylation of signal transducer and activator of transcription-3 (STAT3) was significantly reduced in DHA treatment mice, suggesting that the IL-23/Th17 axis plays a pivotal role. Conclusion: DHA inhibits the progression of psoriasis by regulating IL-23/Th17 axis and is expected to be an effective drug for the treatment of psoriasis.

Primary chondrosarcoma of the liver: A case report.

BACKGROUND: Primary chondrosarcoma of the liver are extremely rare. Moreover, there are few reports focusing on typical clinical symptoms and imaging characteristics. Therefore, the diagnosis of chondrosarcoma of the liver remains a challenge. CASE SUMMARY: A 59-year-old male was admitted due to a lesion occupying the right liver lobe that was found by physical examination. Magnetic resonance imaging showed a lobular mass with high T2 weighted image and low T1 weighted image with enhanced internal separation and edge in the right liver. He was diagnosed with liver cystadenoma by using magnetic resonance imaging. At 3 mo later, the magnetic resonance scan showed that the mass was enlarged. Laparoscopic liver tumor resection was performed with a pathological diagnosis of liver chondrosarcoma. Then he received a surgical resection for the recurrent lesion. However, intrahepatic and abdominal metastases were found again at 8 mo after the second operation. The patient then received conservative management and is now under follow-up. CONCLUSION: Primary liver chondrosarcoma generally is presented as lobulated and heterogeneous density/signal, cystic, solid masses without calcification with enhanced edge, internal septa and solid part. The imaging features are closely related to pathology, which may be helpful for clinical diagnosis.

Asiaticoside Mitigates the Allergic Inflammation by Abrogating the Degranulation of Mast Cells.

The effects of asiaticoside (AS) on allergic responses mediated by mast cells were investigated. AS showed no obvious cytotoxicity on RPMCs (rat peritoneal mast cells). AS reduced the intracellular calcium in RPMCs and deprived the histamine release and degranulation. AS also decreased the generation of antigen-induced tumor necrosis factor α, interleukin (IL)-4, IL-8, and IL-1ß in RBL-2H3 cells sensitized by IgE. The suppression of AS on pro-inflammatory cytokines was related with the activation of the intracellular FcεRI and the inhibition of the nuclear factor-κB signaling pathway. In addition, AS disabled the phosphorylation of antigen-induced Syk, Lyn, Gab2, and PLCγ1, thus suppressing the downstream Akt phosphorylation and MAPKs pathways. It also increased HO-1 and Nrf2 expression time dependently. In summary, we demonstrate that AS suppresses the allergic inflammation mediated by mast cells and this effect might be mediated by FcεRI-dependent signaling pathways.

Sesamin attenuates mast cell-mediated allergic responses by suppressing the activation of p38 and nuclear factor-κB.

Establishing therapeutic agents for the treatment of allergic diseases is an important focus of human health research. Sesamin, a lignan in sesame oil, exhibits a diverse range of pharmacological properties. However, to the best of our knowledge, the effect of sesamin on mast cell­mediated allergic responses has not yet been investigated. Thus, the aim of the present study was to investigate the effect of sesamin on mast cell­mediated allergic responses and the underlying mechanisms by which it produces this effect. In rats, oral administration of sesamin inhibited passive cutaneous anaphylaxis. Sesamin exposure attenuated immunoglobulin E­induced histamine release from rat peritoneal mast cells, which was indicated to be mediated by the modulation of intracellular calcium. In human mast cells, sesamin reduced the stimulatory effects of phorbol 12­myristate 13­acetate and calcium ionophore A23187 on the production and secretion of pro­inflammatory cytokines, including tumor necrosis factor­α and interleukin­6. The inhibitory effect of sesamin on pro­inflammatory cytokine production was dependent on nuclear factor κ­light­chain­enhancer of activated B cells (NF­κB) and p38 mitogen­activated protein kinase (MAPK). The present study demonstrates that sesamin inhibits mast cell­derived inflammatory allergic reactions by blocking histamine release, and pro­inflammatory cytokine production and secretion. In addition, the findings indicate that the effect of sesamin is mediated by its effect on p38 MAPK/NF­κB signaling. Furthermore, the in vivo and in vitro anti­allergic effects of sesamin reported in the present study suggest that it is a promising therapeutic agent for the treatment of inflammatory allergic diseases.

Ginsenoside Rh2 attenuates allergic airway inflammation by modulating nuclear factor-κB activation in a murine model of asthma.

Allergic asthma is a chronic inflammatory disease that is regulated by coordination of T-helper type 2 cell cytokines and inflammatory signaling molecules. Ginsenoside Rh2 (G-Rh2) is an active component of ginseng with anti-inflammatory and anti-tumor effects. The aim of the present study was to determine the inhibitory effects of G-Rh2 on allergic airway inflammation in a murine model of asthma, in which mice develop the following pathophysiological features of asthma: Increased abundance of inflammatory cells; increased levels of interleukin-4 (IL-4), IL-5 and IL-13; decreased abundance of interferon gamma in the bronchoalveolar lavage fluid and lung tissue; increased total and ovalbumin (OVA)-specific immunoglobulin E (IgE) levels in the serum; increased airway hyperresponsiveness (AHR); and activation of nuclear factor kappa B (NF-κB) in lung tissue. In the asthmatic mice, administration of G-Rh2 markedly reduced peribronchiolar inflammation, recruitment of airway inflammatory cells, cytokine production, total and OVA-specific IgE levels and AHR. G-Rh2 administration inhibited NF-κB activation and p38 mitogen-activated protein kinase (MAPK) phosphorylation induced by OVA inhalation. These results suggested that G-Rh2 attenuates allergic airway inflammation by regulating NF-κB activation and p38 MAPK phosphorylation. The present study identified the molecular mechanisms of action of G-Rh2, which supported the potential use of G-Rh2 to prevent and/or treat asthma and other airway inflammatory disorders.

Salidroside attenuates allergic airway inflammation through negative regulation of nuclear factor-kappa B and p38 mitogen-activated protein kinase.

Salidroside is a biologically active ingredient of Rhodiola rosea, which has several interesting biological properties, including anti-oxidant and anti-inflammatory; however, its anti-allergic effects are poorly understood. The objective of this study is to determine whether salidroside attenuates the inflammatory response in an ovalbumin (OVA)-induced asthma model. OVA-sensitized/challenged mice show airway hyperresponsiveness (AHR) to inhaled methacholine and have an increased amount of T-helper2 type cytokines [interleukin (IL)-4, IL-5, and IL-13] and eosinophils in their bronchoalveolar lavage fluids and lung tissues. However, three successive intraperitoneal administrations of salidroside before the last OVA challenge result in significant inhibition of these asthmatic reactions. Moreover, OVA significantly increases the activation of nuclear factor-kappa B (NFκB) and p38 mitogen-activated protein kinase (MAPK) in lung tissues, whereas salidroside markedly suppresses NF-κB translocation and reduces phosphorylation of p38 MAPK. Furthermore, salidroside attenuates the expression of intercellular adhesion molecule 1 and IL-6 through modulating the activities of p38 MAPK and NF-κB in the BEAS-2B cells stimulated by proinflammatory cytokines. These findings indicate that salidroside protects against OVA-induced airway inflammation and AHR, at least in part via downregulation of NF-κB and p38 MAPK activities. Our data support the utility of salidroside as a potential medicine for the treatment of asthma.

Phellinus linteus Extract Exerts Anti-asthmatic Effects by Suppressing NF-κB and p38 MAPK Activity in an OVA-induced Mouse Model of Asthma.

Phellinus linteus has been used as a traditional herbal medicine in Asian countries and is known to have anti-tumor, immunomodulatory, anti-inflammatory, and anti-allergic activities. However, the protective effects of P. linteus against experimental asthma have not been fully investigated. The objective of this study was to determine whether P. linteus ethanol extract (PLE) suppresses inflammatory response in an OVA-induced asthma model. As expected, the oral administration of PLE significantly inhibited eosinophilic airway inflammation and airway hyperresponsiveness in OVA-challenged BALB/c mice. Supporting these data, the augmentation of Th2 cytokines (IL-4, IL-5, and IL-13), eotaxin, and adhesion molecules in lung tissues and bronchoalveolar lavage fluid after OVA inhalation was markedly attenuated by PLE. Furthermore, PLE reduced OVA-induced activation of NF-κB and p38 MAPK in lung tissues. Therefore, our results suggest the potential of P. linteus as a therapeutic agent for asthma.

Inhibition of protein kinase C delta attenuates allergic airway inflammation through suppression of PI3K/Akt/mTOR/HIF-1 alpha/VEGF pathway.

Vascular endothelial growth factor (VEGF) is supposed to contribute to the pathogenesis of allergic airway disease. VEGF expression is regulated by a variety of stimuli such as nitric oxide, growth factors, and hypoxia-inducible factor-1 alpha (HIF-1α). Recently, inhibition of the mammalian target of rapamycin (mTOR) has been shown to alleviate cardinal asthmatic features, including airway hyperresponsiveness, eosinophilic inflammation, and increased vascular permeability in asthma models. Based on these observations, we have investigated whether mTOR is associated with HIF-1α-mediated VEGF expression in allergic asthma. In studies with the mTOR inhibitor rapamycin, we have elucidated the stimulatory role of a mTOR-HIF-1α-VEGF axis in allergic response. Next, the mechanisms by which mTOR is activated to modulate this response have been evaluated. mTOR is known to be regulated by phosphoinositide 3-kinase (PI3K)/Akt or protein kinase C-delta (PKC δ) in various cell types. Consistent with these, our results have revealed that suppression of PKC δ by rottlerin leads to the inhibition of PI3K/Akt activity and the subsequent blockade of a mTOR-HIF-1α-VEGF module, thereby attenuating typical asthmatic attack in a murine model. Thus, the present data indicate that PKC δ is necessary for the modulation of the PI3K/Akt/mTOR signaling cascade, resulting in a tight regulation of HIF-1α activity and VEGF expression. In conclusion, PKC δ may represent a valuable target for innovative therapeutic treatment of allergic airway disease.

Silibinin attenuates allergic airway inflammation in mice.

Allergic asthma is a chronic inflammatory disease regulated by coordination of T-helper2 (Th2) type cytokines and inflammatory signal molecules. Silibinin is one of the main flavonoids produced by milk thistle, which is reported to inhibit the inflammatory response by suppressing the nuclear factor-kappa B (NF-κB) pathway. Because NF-κB activation plays a pivotal role in the pathogenesis of allergic inflammation, we have investigated the effect of silibinin on a mouse ovalbumin (OVA)-induced asthma model. Airway hyperresponsiveness, cytokines levels, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. Pretreatment of silibinin significantly inhibited airway inflammatory cell recruitment and peribronchiolar inflammation and reduced the production of various cytokines in bronchoalveolar fluid. In addition, silibinin prevented the development of airway hyperresponsiveness and attenuated the OVA challenge-induced NF-κB activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-κB activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

[Anthocyanidin inhibits immunoglobulin E-mediated allergic response in mast cells].

This study is to investigate the anti-allergic effect of anthocyanidin and to explore its possible mechanism. The experiments of passive cutaneous anaphylaxis reaction (PCA) and colorimetry were used to determine the effect of anthocyanidin on degranulation of mast cells in vivo. For in vitro study, various concentrations of anthocyanidin (100, 50 and 25 micromol x L(-1)) were added to the culture medium of mast cells cultured with 100 microg x L(-1) of dinitrophenyl (DNP) specific IgE overnight. The azelastine (100 micromol x L(-1)) was selected as the positive control. The antigen (DNP-human serum albumin, DNP-HAS)-induced release of degranulation was measured by enzymatic assay, histamine was determined by EIA, and interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were measured by Western blotting, separately. In addition, the effects of anthocyanidin on phosphorylation of NF-kappaB, p38MAPK and Akt were observed by Western blotting. The results showed that treatments with anthocyanidin (100 and 50 mg x kg(-1)) were followed by a decrease in PCA of rats. Anthocyanidin (100 and 50 micromol x L(-1)) obviously suppressed the degranulation from mast cells, whereas results from anthocyanidin (100 and 50 micromol x L(-1)) group indicated significant inhibitory effect on histamine, the calcium uptake, TNF-alpha, IL-6, phosphorylation of NF-kappaB, p38MAPK and Akt of mast cells induced by antigen. Anthocyanidin may suppress the anaphylactic reaction by inhibiting the action of mast cells. NF-kappaB, p38MAPK and Akt at least in part contribute to this event.

Cornuside suppresses lipopolysaccharide-induced inflammatory mediators by inhibiting nuclear factor-kappa B activation in RAW 264.7 macrophages.

Cornuside, a secoiridoid glucoside compound, was isolated from the fruit of Cornus officinalis SIEB. et ZUCC. Cornuside has been reported to possess immunomodulatory and anti-inflammatory activities. However, the effects and mechanism of action of cornuside in inflammation have not been fully characterized. The present study was therefore designed to examine whether cornuside suppresses inflammatory response in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. Cornuside significantly inhibited the LPS-induced production of nitric oxide, prostaglandin E(2), tumor necrosis factor-alpha, interleukin-6 (IL-6), and IL-1beta. The mRNA and protein expressions of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were also decreased by cornuside. Furthermore, cornuside significantly attenuated the LPS-stimulated phosphorylation and degradation of inhibitory kappa B-alpha and the subsequent translocation of the p65 subunit of nuclear factor-kappa B (NF-κB) to the nucleus. Cornuside also reduced the phosphorylations of extracellular-signal-related kinase (ERK1/2), p38, and c-Jun N-terminal kinase (JNK1/2). These results suggest that the anti-inflammatory property of cornuside is related to the downregulations of iNOS and COX-2 due to NF-κB inhibition as well as the negative regulation of ERK1/2, p38, and JNK1/2 phosphorylations in RAW 264.7 cells.

Protective effect of cornuside against carbon tetrachloride-induced acute hepatic injury.

This study elucidated the effects of cornuside on carbon tetrachloride (CCl4)-induced hepatotoxicity. Rats were treated intraperitoneally with 0.5 mL/kg of CCl4. Sixteen h after CCl4 treatment, the levels of serum aminotransferases, tumor necrosis factor-α (TNF-α), and lipid peroxidation were significantly elevated, whereas the hepatic antioxidative enzyme activities were decreased. These changes were attenuated by cornuside. Histological studies also indicated that cornuside inhibited CCl4-induced liver damage. Furthermore, the contents of hepatic nitrite, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) were elevated after CCl4 treatment, while cytochrome P450 2E1 (CYP2E1) expression was suppressed. Cornuside treatment inhibited the formation of liver nitrite, and reduced the overexpression of iNOS and COX-2 proteins, but restored the liver CYP2E1 content as compared with the CCl4-treated rats. Our data indicate that cornuside protects the liver from CCl4-induced acute hepatotoxicity, perhaps due to its ability to restore the CYP2E1 function and suppress inflammatory responses, in combination with its capacity to reduce oxidative stress.

Inhibitory effects of curcumin on passive cutaneous anaphylactoid response and compound 48/80-induced mast cell activation.

Mast cells participate in allergies and inflammation by secreting a variety of pro-inflammatory mediators. Curcumin, the active component of turmeric, is a polyphenolic phytochemical with anti-tumor, anti-inflammatory, anti-oxidative, and anti-allergic properties. The effects of curcumin on compound 48/80-induced mast cell activation and passive cutaneous anaphylactoid reactions are unknown. In this report, we investigated the influences of curcumin on the passive cutaneous anaphylactoid response in vivo and compound 48/80-induced mast cell activation in vitro. The mechanism of action was examined by calcium uptake measurements and cAMP assays in mast cells. Curcumin significantly attenuated the mast cell-mediated passive cutaneous anaphylactoid reaction in an animal model. In agreement with this in vivo activity, curcumin suppressed compound 48/80-induced rat peritoneal mast cell (RPMC) degranulation and histamine release from RPMCs. Moreover, compound 48/80-elicited calcium uptake into RPMCs was reduced in a dose-dependent manner by curcumin. Furthermore, curcumin increased the level of intracellular cAMP and significantly inhibited the compound 48/80-induced reduction of cAMP in RPMCs. These results corroborate the finding that curcumin may have anti-allergic activity.

Ellagic Acid attenuates immunoglobulin E-mediated allergic response in mast cells.

Ellagic acid is known to have anti-oxidant, anti-carcinogenic and anti-mutagenic effects. However, roles of ellagic acid in the immediate-type allergic reactions have not yet been investigated. In the present study, we have demonstrated that ellagic acid attenuates immunoglobulin (Ig)E-mediated allergic response in mast cells and in vivo. Oral administration of ellagic acid inhibited anti-dinitrophenyl (DNP) IgE-mediated passive cutaneous anaphylaxis. Ellagic acid dose-dependently reduced histamine release and the expression and secretion of pro-inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6 in rat peritoneal mast cells (RPMC) activated by anti-DNP IgE. Moreover, ellagic acid suppressed an increase in intracellular calcium ion concentration ([Ca(2+)](i)) in RPMC. Furthermore, ellagic acid decreased the activation of nuclear factor-kappa B (NF-kappaB). Decreased NF-kappaB activity as well as reduced [Ca(2+)](i) might be involved in the inhibitory effect of ellagic acid on the secretory response. Our findings provide possibility that ellagic acid may serve as an effective therapeutic agent for allergic diseases.

Silibinin attenuates mast cell-mediated anaphylaxis-like reactions.

Silibinin is known to have hepatoprotective, anti-carcinogenic and anti-inflammatory effects. However, roles of silibinin in the immediate-type allergic reactions (anaphylaxis) have not fully been investigated. In the present study, we have demonstrated that silibinin attenuated mast cell-mediated anaphylaxis-like reactions involved in allergic diseases. Oral administration of silibinin inhibited compound 48/80-induced passive cutaneous anaphylaxis-like reaction in mice. Silibinin also attenuated anti-dinitrophenyl (DNP) immunoglobulin (Ig) E-mediated passive systemic and cutaneous anaphylaxis. Silibinin had no cytotoxicity on rat peritoneal mast cells (RPMC). Silibinin dose-dependently reduced histamine release from RPMC activated by compound 48/80 or anti-DNP IgE. Moreover, silibinin inhibited the secretion of pro-inflammatory cytokines, such as tumor necrosis factor-alpha and interleukin-6 in RPMC. Pretreatment of silibinin suppressed the antigen-stimulated calcium uptake and activation of nuclear factor-kappa B (NF-kappaB) in RPMC. Furthermore, silibinin increased the intracellular cAMP level. Increased cAMP, decreased calcium uptake and suppressed NF-kappaB activity might be involved in the inhibitory effect of silibinin on the secretory response. Our findings provide possibility that silibinin may serve as an effective therapeutic agent for allergic diseases.

Pycnogenol inhibits immunoglobulin E-mediated allergic response in mast cells.

IgE-dependent mast cell activation is known to be associated with the allergic diseases. Pycnogenol (PYC) is a standardized extract of the bark of French maritime pine containing bioflavonoids with a potent antioxidant activity. The antiallergic activity of PYC was evaluated using both in vivo and in vitro experimental models. Oral administration of PYC significantly inhibited anti-dinitrophenyl (DNP) IgE-mediated passive cutaneous anaphylaxis in rats. In an in vitro study, PYC dose-dependently reduced histamine release from rat peritoneal mast cells (RPMC) triggered by anti-DNP IgE. PYC inhibited the protein expression and secretion of tumor necrosis factor-alpha and interleukin-6 in anti-DNP IgE-stimulated RPMC. Moreover, PYC decreased anti-DNP IgE-induced calcium uptake into RPMC. Furthermore, PYC suppressed nuclear factor-kappa B activation. From these results, the clinical use of PYC in the mast cell-mediated immediate-type allergic diseases is proposed.

Inhibition of anaphylaxis-like reaction and mast cell activation by water extract from the fruiting body of Phellinus linteus.

Mast cell-mediated anaphylactic reaction is involved in many allergic diseases such as asthma and allergic rhinitis. Phellinus linteus has been used as a traditional herb medicine in oriental countries and is known to have anti-tumor, immunomodulatory, anti-inflammatory, and anti-allergic activities. However, roles of Phellinus linteus in the mast cell-mediated anaphylactic reactions have not fully been examined. In the present study, we have investigated the effects of water extract from the fruiting body of Phellinus linteus (WEPL) on mast cell-mediated anaphylaxis-like reactions. Oral administration of WEPL inhibited the compound 48/80-induced systemic anaphylaxis-like reaction and ear swelling response. WEPL also inhibited the anti-dinitrophenyl (DNP) IgE-mediated passive systemic and cutaneous anaphylaxis. WEPL had no cytotoxicity on rat peritoneal mast cells (RPMC). WEPL dose-dependently reduced histamine release from RPMC activated by compound 48/80 or anti-DNP IgE. Moreover, WEPL decreased the compound 48/80-induced calcium uptake into RPMC. Furthermore, WEPL increased the level of intracellular cAMP and significantly inhibited the compound 48/80-induced cAMP reduction in RPMC. These results suggest that WEPL may serve as an effective therapeutic agent for allergic diseases.