Effect of Agaricus brasiliensis-derived cold water extract on Toll-like receptor 2-dependent cytokine production in vitro

Gastroprotective effect of hydroalcoholic extract from Agaricus blazei Murill against ethanol-induced gastric ulcer in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The use of mushrooms in medicine is quite old and the first report about the use of genus Agaricus in treatment of ulcers occurred in Byzantine period. This mushroom is widely consumed as food, tea, food supplements, as well as nutraceutical and cosmeceutical applications, being cultivated and appreciated in several countries such as Brazil, Korea, Japan and China.

AIM OF THE STUDY

This study aimed to characterize the chemical profile and the potential gastroprotective effect of hydroalcoholic extract from Agaricus blazei Murill (HEAb).

MATERIALS AND METHODS

The extract was chemically characterized by elemental analysis, UPLC-QTOF-MS^E, Nuclear Magnetic Resonance (NMR) and high-performance liquid chromatography (HPLC) techniques to elucidate the metabolites present in the extract. The quantification of phenolic compounds and the in vitro antioxidant activities were performed and the gastroprotective effect of this extract was evaluated against ethanol-induced gastric ulcer model. HEAb was administered by gavage at 5, 25 and 50 mg kg^-1 and N-acetylcysteine at 300 mg kg^-1 (positive control). Furthermore, the pathways of nitric oxide (NO), Cyclic Guanylate Monophosphate (cGMP), prostaglandins (PGs) and the involvement of ATP-sensitive K⁺ Channels were modulated.

RESULTS

Mannitol, malic acid, pyroglutamic acid, L-agaritine and L-valine were putatively identified by UPLC-QTOF-MS^E in HEAb. In addition, it was possible to identify mannitol by the intense signals in the NMR spectra, being still quantified as the main compound in the extract by HPLC. The contents of total phenols and flavonoids corroborated with the good antioxidant activity of HEAb. This study observed that HEAb at 25 and 50 mg kg^-1 had gastroprotection effect demonstrated by the reduction of histopathological parameters and the reduction of mastocytosis in the stomach of mice.

CONCLUSIONS

In this study was possible to conclude that HEAb has gastroprotective effect related to the involvement of NO and PG pathways in the ethanol-induced gastric ulcer model in mice.

Activation of macrophages by a laccase-polymerized polyphenol is dependent on phosphorylation of Rac1

Various physiologically active effects of polymerized polyphenols have been reported. In this study, we synthesized a polymerized polyphenol (mL2a-pCA) by polymerizing caffeic acid using mutant Agaricus brasiliensis laccase and analyzed its physiological activity and mechanism of action. We found that mL2a-pCA induced morphological changes and the production of cytokines and chemokines in C3H/HeN mouse-derived resident peritoneal macrophages in vitro. The mechanisms of action of polymerized polyphenols on in vitro mouse resident peritoneal cells have not been characterized in detail previously. Herein, we report that the mL2a-pCA-induced production of interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1) in C3H/HeN mouse-derived resident peritoneal cells was inhibited by treatment with the Rac1 inhibitor NSC23766 trihydrochloride. In addition, we found that mL2a-pCA activated the phosphorylation Rac1. Taken together, the results show that mL2a-pCA induced macrophage activation via Rac1 phosphorylation-dependent pathways.

Agaricus brasiliensis polysaccharides stimulate human monocytes to capture Candida albicans, express toll-like receptors 2 and 4, and produce pro-inflammatory cytokines

Background

Agaricus brasiliensis is a medicinal mushroom with immunomodulatory and antitumor activities attributed to the β-glucans presented in the polysaccharide fraction of its fruiting body. Since β-glucans enhance cellular immunoresponsiveness, in this study we aimed to evaluate the effect of an acid-treated polysaccharide-rich fraction (ATF) of A. brasiliensis on the ability of human monocytes to adhere/phagocyte C. albicans yeast cells, their expression of pattern recognition receptors and their ability to produce cytokines.

Methods

Adhesion/phagocytosis of FITC-labeled C. albicans was evaluated by flow cytometry. Cells were incubated with specific fluorochrome-labeled antibodies for TLR2 and 4, βGR and MR and also evaluated by flow cytometry. Monocytes were cultured with ATF, and culture supernatants were collected for analysis of in vitro cytokine production by ELISA (TNF-α, IL-1β, IL-12 and IL-10).

Results

ATF significantly increased the adherence/phagocytosis of C. albicans by monocytes and this was associated with enhanced expression of TLR2 and TLR4, while no effect was observed on βGR or MR. Moreover, expression of TLR4 and TLR2 was associated with higher levels of in vitro production of TNF-α and IL-1, respectively. Production of IL-10 was also increased by ATF treatment, but we found no association between its production and the expression of Toll-like receptors.

Conclusion

Our results provided us with evidence that A. brasiliensis polysaccharides affect human monocytes probably through the modulation of Toll-like receptors.

Comparison of Immunomodulatory and Anticancer Activities in Different Strains of Tremella fuciformis Berk

Tremella fuciformis Berk (TF) is a common edible and medicinal mushroom, and has long been used in food and in Chinese medicine. It possesses anticancer, anti-inflammation, anti-oxidative, and neuroprotective abilities. Since their cultivation is a problem, TFs in Taiwan are primarily imported from China, which has a problem with pesticide residues. Thus, the question of whether the Taiwan cultivated TFs, T1, and T6 showed similar or even better results than TFs from China (CH) was assessed in the present study. The results of the physicochemical tests of these TFs showed that T1 extracted by hot water (T1H) has the highest concentration of polysaccharide; meanwhile, T6 extracted by cold water (T6C) showed the highest amount of protein. Regarding the immune modulatory effects of these TFs, hot water extracts of these TFs augmented significantly the inducible nitric oxide synthetase (iNOS), interleukin (IL)-6, and tumor necrosis factor (TNF)-[Formula: see text] mRNA expression than those of cold water extracts. On the other hand, the cold water extracts of TFs, especially of T1C, obviously suppressed cancer cell survival better than those of hot water extracts. Interestingly, we found that hot water extracts of TFs may augment necrotic cell death, whereas, cold water extracts of TFs induce apoptosis. Furthermore, we also showed that these TFs activate caspase-3 cleavage, up regulate the Bax/Bcl-2 ratio, and decrease MMP-9 expressions in PC-3 cells. Taken together, our results indicated that T1 and T6 strains of TFs showed the similar immune modulatory and anticancer abilities were better than the CH strain of TFs.

The TLR2 agonist in polysaccharide-K is a structurally distinct lipid which acts synergistically with the protein-bound β-glucan

Protein-bound polysaccharide-K (Krestin; PSK) is a hot-water extract of Trametes versicolor with immune stimulatory activity. It has been used for the past 30 years and has demonstrated anti-tumor efficacy in multiple types of cancer. The ability of PSK to activate dendritic cells and T cells is dependent on its ability to stimulate Toll-like receptor 2 (TLR2), yet it remains unknown which structural component within PSK activates TLR2. The purpose of this study was to identify the TLR2 agonist within PSK and understand its role in the overall mechanism of PSK's immunogenic activity. TLR2 activity was eliminated by treatment with lipoprotein lipase but not by trypsin or lyticase. Rapid centrifugation of PSK can separate the fraction with TLR2 agonist activity from the soluble β-glucan fraction. To study the potential interaction between the β-glucan component and the lipid component, we labeled the soluble β-glucan with fluorescein. Uptake of the labeled β-glucan by J774A macrophages and JAWSII dendritic cells was inhibited by anti-Dectin-1 antibody but not by anti-TLR2 antibody, confirming that Dectin-1 is the receptor for β-glucan. Interestingly, pre-treatment of JAWSII cells with the TLR2-active lipid fraction significantly enhanced the uptake of the soluble β-glucan, indicating the synergy between the TLR2 agonist component and the β-glucan component. Altogether, these results present evidence that PSK has two active components-the well-characterized protein-bound β-glucan and a previously unreported lipid-which work synergistically via the Dectin-1 and TLR2 receptors.

Differences in antioxidant activities of outdoor- and indoor-cultivated Agaricus brasiliensis, and protective effects against carbon tetrachloride-induced acute hepatic injury in mice

Background

Agaricus brasiliensis (A. brasiliensis) is a medicinal mushroom that exerts various pharmacological actions. We previously demonstrated that different cultivation conditions altered the activity of the polyphenol-related enzymes from this mushroom. However, the influence of cultivation conditions on the antioxidant activity of the fruiting bodies remains unclear. Therefore, in this study we compared the antioxidative effects of fruiting bodies of A. brasiliensis cultivated outdoors and indoors. In addition, we assessed whether different cultivation methods affected the hepatoprotective effects against CCl₄-induced liver injury.

Methods

We assessed the antioxidative effects of mushrooms cultivated in open-air or indoors using the DPPH radical-scavenging assay. Furthermore, we prepared experimental feeds containing outdoor- or indoor-cultivated A. brasiliensis. Acute liver injury was induced by CCl₄ injection in mice that consumed feed containing outdoor- or indoor-cultivated A. brasiliensis. The hepatoprotective effects of these mushrooms were then evaluated by monitoring the reduction in the circulating levels of alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase. The significance of the differences between the means was assessed using Student’s t-test. Finally, histopathological analysis of liver was performed.

Results

In the DPPH assay, the antioxidant activity of outdoor-cultivated A. brasiliensis was higher than that of indoor-cultivated mushroom. Moreover, in the mouse model of CCl₄-induced hepatitis, the oral administration of outdoor-cultivated A. brasiliensis reduced liver damage significantly, but indoor-cultivated mushrooms failed to inhibit hepatitis. The hepatoprotective effects of outdoor-cultivated A. brasiliensis were observed even when ingestion commenced only 1 day before CCl₄ injection, and these effects were not affected by excessive heat treatment.

Conclusions

Outdoor cultivation significantly enhanced the antioxidative activity of A. brasiliensis fruiting bodies. In addition, outdoor-cultivated A. brasiliensis was more effective at protecting against CCl₄-induced liver injury in mice than mushrooms grown in a greenhouse.

Clitocybe nuda Activates Dendritic Cells and Acts as a DNA Vaccine Adjuvant

This work represents the first evaluation of the effects of water extract of C. nuda (WE-CN), an edible mushroom, on murine bone marrow-derived dendritic cells (BMDCs) and the potential pathway through which the effects are mediated. Our experimental results show that WE-CN could induce phenotypic maturation of DCs, as shown by the increased expression of MHC and costimulatory molecules. In addition, it also induced the proinflammatory cytokines expression on DCs and enhanced both the proliferation and IFN- γ secretion of allogenic T cells. Therefore, since WE-CN did not induce maturation of DCs generated from mice with mutated TLR-4 or TLR-2, suggesting that TLR4 and TLR2 might function as membrane receptors for WE-CN. Moreover, the mechanism of action of WE-CN may be mediated by increased phosphorylation of ERK, p38, and JNK mitogen-activated protein kinase (MAPK) and increased NF- κ B p65 activity, which are important signaling molecules downstream of TLR-4 and TLR-2. Finally, coimmunization of mice with WE-CN and a HER-2/neu DNA vaccine induced a HER-2/neu-specific Th1 response that resulted in significant inhibition of HER-2/neu overexpressing mouse bladder tumor (MBT-2) growth. These data suggest that WE-CN induces DC maturation through TLR-4 and/or TLR-2 and that WE-CN can be used as an adjuvant in cancer vaccine immunotherapy.

Modulation of interferon-γ synthesis by the effects of lignin-like enzymatically polymerized polyphenols on antigen-presenting cell activation and the subsequent cell-to-cell interactions

Lignin-like polymerized polyphenols strongly activate lymphocytes and induce cytokine synthesis. We aimed to characterise the mechanisms of action of polymerized polyphenols on immunomodulating functions. We compared the reactivity of leukocytes from various organs to that of polymerized polyphenols. Splenocytes and resident peritoneal cavity cells (PCCs) responded to polymerized polyphenols and released several cytokines, whereas thymocytes and bone-marrow cells showed no response. Next, we eliminated antigen-presenting cells (APCs) from splenocytes to study their involvement in cytokine synthesis. We found that APC-negative splenocytes showed significantly reduced cytokine production induced by polymerized polyphenols. Additionally, adequate interferon-γ (IFN-γ) induction by polymerized polyphenols was mediated by the coexistence of APCs and T cells because the addition of T cells to PCCs increased IFN-γ production. Furthermore, inhibition of the T cell-APC interaction using neutralising antibodies significantly decreased cytokine production. Thus, cytokine induction by polymerized polyphenols was mediated by the interaction between APCs and T cells.

Agaricus brasiliensis-derived β-glucans exert immunoenhancing effects via a dectin-1-dependent pathway

Agaricus brasiliensis is a well-known medicinal mushroom. We have previously demonstrated that Agaricus-derived polysaccharides exhibit potent antitumor effects; however, the underlying mechanism(s) have not been elucidated yet. In this study, we examined the immunoenhancing activities of Agaricus extracts. Agaricus-derived polysaccharides were characterized as 1,6-β-glucan with a small amount of 1,3-β-glucan using anti-β-glucan antibody and nuclear magnetic resonance analysis. These polysaccharides strongly induced the production of various cytokines from both murine splenocytes and bone marrow-derived dendritic cells in the presence of exogenous granulocyte-macrophage colony-stimulating factor. Polysaccharide-induced cytokine production was significantly reduced in bone marrow-derived dendritic cells derived from dectin-1-deficient mice. Furthermore, a binding assay revealed that the Agaricus-derived polysaccharides can be recognized by dectin-1, a pivotal receptor for 1,3-β-glucan. Taken together, our results clearly indicate that the immunostimulation induced by Agaricus-derived polysaccharides is exerted, at least in part, via dectin-1 in combination with granulocyte-macrophage colony-stimulating factor.

The effect of enzymatically polymerised polyphenols on CD4 binding and cytokine production in murine splenocytes

High-molecular weight polymerised polyphenols have been shown to exhibit anti-influenza virus, anti-HIV, and anti-cancer activities. The purpose of this study was to evaluate the immunomodulating activities of enzymatically polymerised polyphenols, and to clarify the underlying mechanisms of their effects. The cytokine-inducing activity of the enzymatically polymerised polyphenols derived from caffeic acid (CA), ferulic acid (FA), and p-coumaric acid (CoA) was investigated using murine splenocytes. Polymerised polyphenols, but not non-polymerised polyphenols, induced cytokine synthesis in murine splenocytes. Polymerised polyphenols induced several cytokines in murine splenocytes, with interferon-γ (IFN-γ) and granulocyte-macrophage colony-stimulating factor (GM-CSF) being the most prominent. The underlying mechanisms of the effects of the polymerised polyphenols were then studied using neutralising antibodies and fluorescent-activated cell sorting (FACS) analysis. Our results show that polymerised polyphenols increased IFN-γ and GM-CSF production in splenocytes. In addition, the anti-CD4 neutralised monoclonal antibody (mAb) inhibited polymerised polyphenol-induced IFN-γ and GM-CSF secretion. Moreover, polymerised polyphenols bound directly to a recombinant CD4 protein, and FACS analysis confirmed that interaction occurs between polymerised polyphenols and CD4 molecules expressed on the cell surface. In this study, we clearly demonstrated that enzymatic polymerisation confers immunoactivating potential to phenylpropanoic acids, and CD4 plays a key role in their cytokine-inducing activity.