Inducement of cytokine release by GFPBW2, a novel polysaccharide from fruit bodies of Grifola frondosa , through dectin-1 in macrophages

Polysaccharides, especially β-glucans isolated from various species of mushrooms, are considered as biological response modifiers (BRMs) to be widely used in the treatment of cancer, especially due to their immunostimulatory activity. We herein characterized the structure of a novel water-soluble homogeneous polysaccharide (GFPBW2) from the fruit bodies of mushroom Grifola frondosa and investigated its immunomodulatory activity in vitro. GFPBW2 was purified from the alkali-extracted fractions by stepwise elution with a molecular weight of 26.2 kDa. On the basis of infrared and NMR spectroscopy, methylation and monosaccharide composition analysis, partial acid hydrolysis, and Smith degradation, its structure was elucidated to possess a backbone consisting of β-d-1,3- and β-d-1,4-linked glucopyranosyl residues, with branches attached to O-6 of β-d-1,3-linked glucopyranosyl residues. Functionally, it is an effective inducer of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) secretion in murine resident peritoneal macrophages. Using quartz crystal microbalance (QCM) analysis, we found that GFPBW2 could bind dendritic cell-associated C-type lectin-1 (Dectin-1) with an affinity constant (Kd) value of 1.08 × 10 (-7) M, while it could activate Syk and enhance TNF-α production in RAW264.7 cells overexpressing wild type but not mutant Dectin-1. Furthermore, Syk, NF-κB signaling, and cytokine release in resident peritoneal macrophages induced by GFPBW2 could be significantly inhibited by a specific Dectin-1 blocking reagent, Laminarin. These data suggested that GFPBW2 might be a potential ligand of Dectin-1, and the potential of GFPBW2 to activate macrophage through triggering cytokine secretion might be attributed, at least in part, to the involvement of Dectin-1.

Inhibitory effect of sulfated lentinan and lentinan against tobacco mosaic virus (TMV) in tobacco seedlings

The antiviral activities of sulfated lentinan (sLNT) and lentinan (LNT) against tobacco mosaic virus (TMV) in tobacco seedlings and the underlying mechanism were investigated. Compared with LNT, sLNT showed significantly higher inhibitory effects on viral infection and TMV multiplication in a dose-dependent way, which might be due to its binding with TMV coat protein. In addition, both sLNT and LNT induced the transient production of H2O2 and expression of some defense-related genes (stilbene synthase, glucanase, acidic chitinase class IV, phenylalanine ammonia-lyase and 5-epi-aristolochene synthase) both locally and systemically. These results suggested that sLNT and LNT could control TMV incidence and the action mechanism might be associated with the affinity towards TMV coat protein and activation of some defense genes.

Structure analysis and antimutagenic activity of a novel salt-soluble polysaccharide from Auricularia polytricha

BACKGROUND

Auricularia polytricha is known to be a highly nutritious foodstuff. We report here the purification, structure characterization and antimutagenic activity in vivo of a 0.9% NaCl solution-soluble polysaccharide (SSP) from the mycelia of A. polytricha.

RESULTS

Analysis by high-performance liquid chromatography coupled to a TSK-G5000PWXL column and gel filtration chromatography on Sephacryl S-400 HR indicated that SSP is homogeneous with an average molecular weight of about 9.30 × 10(5) Da. The structure of SSP was revealed by chemical methods, Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Results indicated that SSP is a glucan consisting of a1,3-β-glucan, 1,6-α-glucan, 1,4-α-glucan and 1,3-α-glucan backbone with a single 1,6-α-d-glucopyranosyl side-branching unit on every nine residues, on average, along the main chain. Atomic force microscopy indicates the presence of macromolecular species in morphology and shows a clear association of prolate particle. Meanwhile, SSP was found to significantly preventing micronuclei in polychromatic erythrocytes and reticulocytes of mice (P < 0.01).

CONCLUSION

These results indicate that polysaccharide SSP from A. polytricha exhibits antimutagenic activity against the in vivo DNA-damaging effect of the indirectly acting alkylating agent cyclophosphamide.

ROS-dependent mitochondria molecular mechanisms underlying antitumor activity of Pleurotus abalonus acidic polysaccharides in human breast cancer MCF-7 cells

Background

A greater reduction in cancer risk associated with mushroom diet rich in fungus polysaccharides is generally accepted. Meanwhile, edible Pleurotus abalonus as a member of Abalone mushroom family is a popular nutritional supplement that purportedly prevents cancer occurrence. However, these anecdotal claims are supported by limited studies describing tumor-inhibitory responses to the promising polysaccharides, and the molecular mechanisms underlying these properties have not yet been elucidated.

Methodology/Principal Findings

We here fractionated the crude polysaccharide preparation from the fruiting bodies of P. abalonus into three fractions, namely PAP-1, PAP-2 and PAP-3, and tested these fractions for antiproliferative activity in human breast cancer MCF-7 cells. The largest PAP-3, an acidic polysaccharide fraction with a molecular mass of 3.68×10⁵ Da, was the most active in inhibiting MCF-7 cancer cells with an IC₅₀ of 193 µg/mL. The changes in cell normal morphology were observed by DAPI staining and the PAP-3-induced apoptosis was confirmed by annexin V/propidium iodide staining. The apoptosis was involved in mitochondria-mediated pathway including the loss of mitochondrial membrane potential (Δψm), the increase of Bax/Bcl-2 ratio, caspase-9/3 activation, and poly(ADP-ribose) polymerase (PARP) degradation, as well as intracellular ROS production. PAP-3 also induced up-regulation of p53, and cell cycle arrest at the S phase. The incubation of MCF-7 cells with antioxidant superoxide dismutase (SOD) and N-acetylcysteine (NAC) significantly attenuated the ROS generation and apoptosis caused by PAP-3, indicating that intracellular ROS plays a pivotal role in cell death.

Conclusions/Significance

These findings suggest that the polysaccharides, especially acidic PAP-3, are very important nutritional ingredients responsible for, at least in part, the anticancer health benefits of P. abalonus via ROS-mediated mitochondrial apoptotic pathway. It is a major breakthrough bringing new insight of the potential use of the polysaccharides as health-care food or medicine to provide significant natural defense against human cancer.

The physicochemical properties of a new class of anticancer fungal polysaccharides: a comparative study

The structural and physicochemical properties of polysaccharides isolated from fungi with anticancer properties were investigated. The majority of the polysaccharides considered, have the β-d-Glcp component mostly connected by 1→3 and 1→6 linkages in the backbones and the short branches, respectively. The established parameters of lead-like, drug-like and of known dug space (KDS) were used and the repeating units of the polysaccharides exhibit some overlap with these. It was found that a unique region of chemical space is occupied by the polysaccharides, with MW: 1.0 x 10(5) to 2.5 x 10(5) g mol(-1); LogP: -3.0 x 10(3) to -1.0 x 10(3); HD: 1.0 x 10(3) to 5.0 x 10(3); HA: 5.0 x 10(3) to 1.0 x 10(4); PSA: 5.0 x 10(4) to 1.0 x 10(5) and RB: 5.0 x 10(3) to 1.0 x 10(4). These findings can be exploited in antitumor drug discovery projects.

Optimization extraction of Ganoderma lucidum polysaccharides and its immunity and antioxidant activities

Extraction of Ganoderma lucidum polysaccharides (GLP) was optimized by response surface method (RSM). By running the optimization program with design expert within the experimental range investigated, the following optimum values were obtained: extraction time 230 min; extraction temperature 95 °C, and extraction number 5. The predicted polysaccharides production was 1.45%. Results showed that GLP significantly reduced the levels of serum IL-6 and TNF-α levels and increased the levels of serum IL-2, IL-4 and IL-10 in GLP-treated rats compared to gastric cancer model rats. In addition, administration of Ganoderma lucidum polysaccharides to GLP-treated group of rats improved the levels of serum and gastric tissue SOD, CAT and GSH-Px toward the control values in a dose-dependent manner. These findings show that GLP can enhance immunity and antioxidant activities in gastric cancer rats.

[Beta-glucan content and hydration properties of filamentous fungi]

The aim of this work was to isolate and identify filamentous fungi from several sources to study the dietary fiber and beta-glucan content. The fungal hydration properties such as water absorption and water holding capacities were also evaluated. Total dietary fiber of isolates exhibited a noticeable variability from 16 to 53% and the highest values were obtained for the genera Paecilomyces and Penicillium, a fact consistent with a higher content of beta-glucans (24 and 17%, respectively), higher than previously reported for Basidiomycetes and yeast. We observed a large decrease (75%) in the water holding capacity when the mycelia were dried. Isolates of filamentous fungi with greater water holding capacity also exhibited greater absorption capacity. Paecilomyces variotii and Penicillium nalgiovense had the best hydration properties. Our results contribute to the search for new unconventional ingredients providing a high protein and beta-glucans content. The addition of these dried mycelia could change the hydration properties in the food system.

Sulfation and enhanced antioxidant capacity of an exopolysaccharide produced by the medicinal fungus Cordyceps sinensis

EPS-1 was an exopolysaccharide produced by the medicinal fungus Cordyceps sinensis (Cs-HK1). In the present study, EPS-1 was sulfated with chlorosulfonic acid (CSA)-pyridine (Pyr) at different volume ratios, yielding four sulfated derivatives, SEPS-1A, B, C and D, with different degrees of substitution (DS: 0.25–1.38) and molecular weights (17.1–4.1 kDa). The sulfation of EPS-1 occurred most frequently at the C-6 hydroxyl groups due to their higher reactivity. In aqueous solution, the native EPS-1 formed random coils or aggregated networks, but the sulfated derivatives formed single helices. The antioxidant activities of the sulfated EPS-1 derivatives for scavenging hydroxyl radicals (•OH) and 2,2-azinobis-3-ehtylbenzothiazolin-6-sulfonic acid radicals (ABTS•+) were significantly increased with increasing DS and decreasing molecular weight (MW). Sulfation has thus been shown to be an effective and favorable strategy for improving the physico-chemical properties and bioactivities of fungal polysaccharides.

Polysaccharide from Lentinus edodes inhibits the immunosuppressive function of myeloid-derived suppressor cells

Reversing the function of immune suppressor cells may improve the efficacy of cancer therapy. Here, we have isolated a novel polysaccharide MPSSS (577.2 Kd) from Lentinus edodes and examined its effects on differentiation and function of myeloid-derived suppressor cells (MDSCs). MPSSS is composed of glucose (75.0%), galactose (11.7%), mannose (7.8%), and xylose (0.4%). In vivo, it inhibits the growth of McgR32 tumor cells, which is correlated with a reduced percentage of MDSCs in peripheral blood. In vitro, it induces both morphological and biophysical changes in MDSCs. Importantly, MPSSS up-regulates MHC II and F4/80 expression on MDSCs, and reverses their inhibition effect on CD4⁺ T cells in a dose-dependent manner. The mechanism study shows that MPSSS may stimulate MDSCs through a MyD88 dependent NF-κB signaling pathway. Together, we demonstrated for the first time that MPSSS stimulates the differentiation of MDSCs and reverses its immunosuppressive functions, shedding new light on developing novel anti-cancer strategies by targeting MDSCs.

Effect of yeast polysaccharide on some hematologic parameter and gut morphology in channel catfish (Ictalurus punctatus)

A study was conducted to investigate the effect of dietary yeast polysaccharides on some hematologic parameters and intestinal morphology of channel catfish. Channel catfish were fed diets containing yeast polysaccharides at 0 (control), 0.1, 0.2, or 0.3 % for 7 weeks. Each diet was provided to 10 channel catfish specimens (5.82 ± 0.13 g initial weight) replicated 3 times in individual 250 L fiberglass tanks. Some hematologic parameters, leukocyte phagocytic activity, and intestinal morphology were monitored. After 7 weeks of trial, 0.2 % yeast polysaccharides resulted in significantly higher (P < 0.05) monocyte numbers. Furthermore, fish fed 0.2 % yeast polysaccharide diet had higher (P < 0.05) phagocytic rate of leukocyte. And 0.3 % yeast polysaccharide enhanced (P < 0.05) phagocytic index of leukocyte. Histological evaluation showed yeast polysaccharide supplementation increased the height of intestine fold (0.1, 0.2 and 0.3 %) and the thick of muscular layers (0.2 %) in intestine (P < 0.05). In addition, 0.1 and 0.3 % yeast polysaccharide supplementation improved the number of goblet cells (P < 0.05). The results of this trial indicate that yeast polysaccharides supplementation could affect blood monocytes, improve leukocytes phagocytic activity, and the development of intestine in channel catfish.

Immunomodulatory effect of polysaccharides from submerged cultured Cordyceps gunnii

CONTEXT

The genus Cordyceps (Clavicipitaceae) is a group of entomopathogenic fungi that is widely used as tonic food or invigorant with broad-spectrum medicinal properties in China. Cordyceps gunnii (Berk.)Berk (C. gunnii), is also well known as the Chinese rare caterpillar fungus and has similar pharmacological activities with Cordyceps sinensis (C. sinensis). Polysaccharides (PS) from various Cordyceps species have demonstrated many interesting biological activities, including antitumor, immunopotentiation, hypoglycemic, and hypocholesterolemic activities.

OBJECTIVE

To investigate the effect of C. gunnii PS on the immunostimulatory antitumor function and expression of immune related cytokines in normal, immuno-suppressive, and H22-bearing mice, respectively.

METHODS

C. gunnii PS were extracted with hot water at 80°C for 2 h. Normal, immuno-suppressive, and H22-bearing mice were treated with PS respectively. By detecting the value of macrophage phagocytic index, proliferation of lymphocytes, natural killer (NK) cell activity and expression of related cytokines, interleukin (IL-4), tumor necrosis factor-α (TNF-a) and interferon-γ (IFN-γ), and tumor inhibition index in H22-bearing mice additionally, the effect of PS on immunostimulatory antitumor function and its mechanism were studied.

RESULTS

The total sugar content of the PS was determined to be 95% after purification. PS markedly increased the thymus and spleen indexes, the macrophage phagocytosis, the proliferation of splenic cells, and the level of IFN-γ and TNF-α. In tumor growth inhibition test, PS showed remarkable inhibition effects.

CONCLUSION

PS from the C. gunnii could enhance nonspecific immunological function, humoral immunity, cellular immunity in mice, and inhibit tumor growth.

Antioxidative properties of crude polysaccharides from Inonotus obliquus

The mushroom Inonotus obliquus has been widely used as a folk medicine in Russia, Poland and most of the Baltic countries. In this study, water-soluble and alkali-soluble crude polysaccharides (IOW and IOA) were isolated from I. obliquus, and the carbohydrate-rich fractions IOW-1 and IOA-1 were obtained respectively after deproteination and depigmentation. Their contents, such as neutral carbohydrate, uronic acid and protein, were measured. Their antioxidant properties against chemicals-induced reactive species (ROS) including 1,1'-Diphenyl-2-picrylhydrazyl (DPPH) radical, hydroxyl radical and superoxide anion radical, as well as their protective effects on H(2)O(2)-induced PC12 cell death were investigated. Results showed that I. obliquus polysaccharides can scavenge all ROS tested above in a dose-dependent manner. IOA and its product IOA-1 could rescue PC12 cell viability from 38.6% to 79.8% and 83.0% at a concentration of 20μg/mL. Similarly, IOW and its product IOW-1 at the same dose, can also increase cell viability to 84.9% and 88.6% respectively. The antioxidative activities of water-soluble and alkali-soluble polysaccharide constituents from I. obliquus might contribute to diverse medicinal and nutritional values of this mushroom.

The polysaccharides from Ganoderma lucidum: Are they always inhibitors on human hepatocarcinoma cells?

The antitumor activity of intracellular polysaccharides from submerged fermentation of Ganoderma lucidum was investigated focusing on the inhibition on human liver cancer cells. The polysaccharides inhibited human hepatocarcinoma cell HepG2 during earlier phase with lower dosage but obviously became less functional in later phase regardless of the dosage applied. However, apoptosis of the drugged HepG2 cells appeared in later incubation phase with high dosage, and the apoptosis could be enhanced by supplemental dose of the intracellular polysaccharides. Nevertheless, the intracellular polysaccharides inhibited other human hepatocarcinoma cells such as BEL-7402 and Huh-7 but luckily stimulated human normal liver cell L02 only in a positive dose- and time-dependent manner; so did the sulfated extracellular polysaccharides when it inhibited HepG2 and L02 cells. However, the toxicity of sulfated extracellular polysaccharides to L02 cells can be eliminated by the intracellular polysaccharides.

Production, characterization and antioxidant activity of exopolysaccharides from submerged culture of Morchella crassipes

The aim of this work was to investigate the fermentation optimization, molecular characterization, and antioxidant activity in vitro of exopolysaccharides (EPS) from Morchella crassipes in submerged culture. Firstly, an optimal medium for EPS production was obtained by single-factor experiment and central composite design as follows: maltose 44.79 g/L and tryptone 4.21 g/L. Then, one fraction of EPS was obtained from the culture filtrates by size exclusion chromatography and the molecular characteristics were examined by a multi-angle laser light scattering and refractive index detector system. The weight-average molar mass and the polydispersity ratio of the EPS fraction were revealed to be 1.961 × 10(4) g/mol and 1.838, respectively. FT-IR spectroscopy was used for obtaining vibrational spectra of the purified EPS fraction. Finally, the antioxidant activity of EPS was investigated and the relationship with molecular properties was discussed as well.