The effects of beta-glucan on human immune and cancer cells

Tramesan, a novel polysaccharide from Trametes versicolor. Structural characterization and biological effects

Mushrooms represent a formidable source of bioactive compounds. Some of these may be considered as biological response modifiers; these include compounds with a specific biological function: antibiotics (e.g. plectasin), immune system stimulator (e,g, lentinan), antitumor agents (e.g. krestin, PSK) and hypolipidemic agents (e.g. lovastatin) inter alia. In this study, we focused on the Chinese medicinal mushroom "yun zhi", Trametes versicolor, traditionally used for (cit.) "replenish essence and qi (vital energy)". Previous studies indicated the potential activity of extracts from culture filtrate of asexual mycelia of T. versicolor in controlling the growth and secondary metabolism (e.g. mycotoxins) of plant pathogenic fungi. The quest of active principles produced by T. versicolor, allowed us characterising an exo-polysaccharide released in its culture filtrate and naming it Tramesan. Herein we evaluate the biological activity of Tramesan in different organisms: plants, mammals and plant pathogenic fungi. We suggest that the bioactivity of Tramesan relies mostly on its ability to act as pro antioxidant molecule regardless the biological system on which it was applied.

Mushrooms: from nutrition to mycoremediation

Mushrooms are well known as important food items. The uses of mushrooms in the cuisine are manifolds and are being utilized for thousands of years in both Oriental and Occidental cultures. Medicinal properties of mushrooms show an immense potential as drugs for the treatment of various diseases as they are rich in a great variety of phytochemicals. In this review, we attempted to encompass the recent knowledge and scientific advancement about mushrooms and their utilization as food or curative properties, along with their natural ability to accumulate (heavy) metals/radionuclides, which leads to an important aspect of bioremediation. However, accumulation of heavy metals and radionuclides from natural or anthropogenic sources also involves potential nutritional hazards upon consumption. These hazards have been pointed out in this review incorporating a selection of the most recently published literature.

High- and low-Molecular Weight oat Beta-Glucan Reveals Antitumor Activity in Human Epithelial Lung Cancer

Beta-glucans are widely used in treatment, cosmetics, and the food industry. Glucans play a significant role in activation of the immune and antioxidant system and inhibiting tumor proliferation. In the current study the antitumor activities of new high and low molecular weight beta-glucan derived from oats were investigated in two human lung cancer cell line (A549, H69AR) and normal keratinocytes (HaCaT). The effect of high and low molecular weight beta-glucan from oat was evaluated by cellular viability assessment, lipid peroxidation and manganese superoxide dismutase evaluation and cytoskeleton visualisation. Additionally the level of red blood cells hemolysis was performed. Our results indicate strong anti-tumor properties of new beta-glucan from oat and at the same time no toxicity for normal cells.

Tile-based self-assembly of a triple-helical polysaccharide into cell wall-like mesoporous nanocapsules

Tile-based self-assembly is a robust system in the construction of three-dimensional DNA nanostructures but it has been rarely applied to other helical biopolymers. β-Glucan is an immunoactive natural polymer which exists in a triple helical conformation. Herein, we report that β-glucan, after modification using two types of short chain acyl groups, can self-assemble into tiles with inactivated sticky ends at the interface of two solvents. These tiles consist of a single layer of helices laterally aligned, and the sticky ends can be activated when a few acyl groups at the ends are removed; these tiles can further pack into mesoporous nanocapsules, in a similar process as the sticky DNA tiles pack into complex polyhedral nano-objects. These nanocapsules were found to have targeted effects to antigen presenting cells in a RAW264.7 cell model. Our study suggests that tile-based self-assembly can be a general strategy for helical biopolymers, and on fully exploiting this strategy, various new functional nanostructures will become accessible in the future.

Respiratory Tract Infections and the Role of Biologically Active Polysaccharides in Their Management and Prevention

Respiratory tract infections (RTIs) are the most common form of infections in every age category. Recurrent respiratory tract infections (RRTIs), a specific form of RTIs, represent a typical and common problem associated with early childhood, causing high indirect and direct costs on the healthcare system. They are usually the consequence of immature immunity in children and high exposure to various respiratory pathogens. Their rational management should aim at excluding other severe chronic diseases associated with increased morbidity (e.g., primary immunodeficiency syndromes, cystic fibrosis, and ciliary dyskinesia) and at supporting maturity of the mucosal immune system. However, RRTIs can also be observed in adults (e.g., during exhausting and stressful periods, chronic inflammatory diseases, secondary immunodeficiencies, or in elite athletes) and require greater attention. Biologically active polysaccharides (e.g., β-glucans) are one of the most studied natural immunomodulators with a pluripotent mode of action and biological activity. According to many studies, they possess immunomodulatory, anti-inflammatory, and anti-infectious activities and therefore could be suggested as an effective part of treating and preventing RTIs. Based on published studies, the application of β-glucans was proven as a possible therapeutic and preventive approach in managing and preventing recurrent respiratory tract infections in children (especially β-glucans from Pleurotus ostreatus), adults (mostly the studies with yeast-derived β-glucans), and in elite athletes (studies with β-glucans from Pleurotus ostreatus or yeast).

Olive Mill Waste Enhances α-Glucan Content in the Edible Mushroom Pleurotus eryngii

Mushroom polysaccharides are edible polymers that have numerous reported biological functions; the most common effects are attributed to β-glucans. In recent years, it became apparent that the less abundant α-glucans also possess potent effects in various health conditions. Here we explore several Pleurotus species for their total, β and α-glucan content. Pleurotus eryngii was found to have the highest total glucan concentrations and the highest α-glucans proportion. We also found that the stalks (stipe) of the fruit body contained higher glucan content then the caps (pileus). Since mushrooms respond markedly to changes in environmental and growth conditions, we developed cultivation methods aiming to increase the levels of α and β-glucans. Using olive mill solid waste (OMSW) from three-phase olive mills in the cultivation substrate. We were able to enrich the levels mainly of α-glucans. Maximal total glucan concentrations were enhanced up to twice when the growth substrate contained 80% of OMSW compared to no OMSW. Taking together this study demonstrate that Pleurotus eryngii can serve as a potential rich source of glucans for nutritional and medicinal applications and that glucan content in mushroom fruiting bodies can be further enriched by applying OMSW into the cultivation substrate.

MafB silencing in macrophages does not influence the initiation and growth of lung cancer induced by urethane

An increased number of tumor-associated macrophages (TAMs) that exhibit the M2 macrophage phenotype is related to poorer prognosis in cancer patients. MafB is a transcription factor regulating the differentiation of macrophages. However, involvement of MafB for the development of TAMs is unknown. This study was designed to investigate the role of MafB in a murine urethane-induced lung cancer model. Urethane was injected intraperitoneally into wild-type and dominant-negative MafB transgenic mice. Twenty-four weeks later, mice were sacrificed and their lungs removed for pathological analysis. The numbers and mean areas of lung cancer were evaluated. In addition, the numbers of Mac-3-positive macrophages were evaluated in each tumor. The numbers and mean areas of lung cancer induced by urethane administration were not significantly different between wild-type and dominant-negative MafB transgenic mice. The numbers of TAMs in lung cancer tissue were not significantly different between the two groups. MafB silencing using dominant-negative MafB did not influence the initiation and growth of lung cancer in mice exposed to urethane. These data suggest that MafB may not be related to the development of TAMs.

Inflammation-associated gene expression in RAW 264.7 macrophages induced by toxins from fungi common on damp building materials

Most fungi that grow on damp building materials produce low molecular weight compounds, some of which are known to be toxic. In this study, we tested the hypothesis that exposure to some metabolites of fungi common on damp building materials would result in time-, dose-, and compound-specific responses in the production of various chemokines by RAW 264.7 cells. Cell cultures were exposed to a 10^-7M or 10^-8M metabolite dose for 2, 4, 8 or 24h. Metabolite concentrations used were based on those that might be expected in alveolar macrophages due to inhalation exposure from living or working in a damp building. Compared to controls, exposure provoked significant time-, dose- and compound-specific responses manifest as differentially elevated secretion of three of nine cytokines tested in culture supernatant of treated cells. The greatest number of cytokines produced in response to the metabolites tested were in andrastin A-treated cells (GM-CSF, TGFβ1, Tnf-α) followed by koninginin A (TGFβ1 and Tnf-α) and phomenone (GM-CSF, TGFβ1). Chaetoglobosin A, chaetomugilin D and walleminone exposures each resulted in significant time-specific production of Tnf-α only. This investigation adds to a body of evidence supporting the role of low molecular weight compounds from damp building materials as pathogen associated molecular patterns (PAMPs). Along with fungal glucan and chitin, these compounds contribute to the non-allergy based respiratory outcomes for people living and working in damp buildings.

On importance of impurities, potential leachables and extractables in algal nanocellulose for biomedical use

Nanocellulose-based biomaterials for biomedical and pharmaceutical applications have been extensively explored. However, studies on different levels of impurities in the nanocellulose and their potential risks are lacking. This article is the most comprehensive to date survey of the importance and characterization of possible leachables and extractables in nanocellulose for biomedical use. In particular, the (1,3)-β-d-glucan interference in endotoxin detection in algal nanocellulose was addressed. Potential lipophilic and hydrophilic leachables, toxic heavy metals, and microbial contaminants are also monitored. As a model system, nanocellulose from Cladophora sp. algae is investigated. The leachable (1,3)-β-d-glucan and endotoxin, which possess strong immunogenic potential, from the cellulose were minimized to clinically insignificant levels of 4.7μg/g and 2.5EU/g, respectively. The levels of various impurities in the Cladophora cellulose are acceptable for future biomedical applications. The presented approach could be considered as a guideline for other types of nanocellulose.

Neoagarooligosaccharides prevent septic shock by modulating A20-and cyclooxygenase-2-mediated interleukin-10 secretion in a septic-shock mouse model

Analysis of the signaling mechanism triggered by endotoxin-mediated toll-like receptor-4 activation using immune cell systems or rodent models may help identify potential agents for the prevention of Gram-negative bacteria infection. β-agarase cleaves the β-1,4-linkages of agar to produce neoagarooligosaccharides (NAOs), which have various physiological functions. The aim of this study was to investigate the efficacy of NAOs in preventing experimental sepsis caused by the administration of endotoxin or Gram-negative bacteria. Organ damage and neutrophil infiltration in an endotoxemia and septic-shock mouse model were suppressed by NAOs. Pro-inflammatory cytokine level was decreased, but IL-10 level was increased by NAO-treatment. Further induction by NAOs in the presence of endotoxin was associated with a significant induction of A20 and cyclooxygenase (COX)-2 expressions. Our data suggest that NAOs have a beneficial preventive effect in septic shock correlated with the enhancement of IL-10 via the induction of A20 and COX-2.

Influence of carrageenan on cytokine production and cellular activity of mouse peritoneal macrophages and its effect on experimental endotoxemia

The in vivo effect of κ/β-carrageenan isolated from the red alga Tichocarpus crinitus on cytokine synthesis and cellular activity of murine peritoneal macrophages and also the protective effect of polysaccharides in LPS-induced endotoxemia in mice was studied. It was established that κ/β-carrageenan given orally at a dose of 100 mg/kg stimulates the induction of anti-inflammatory cytokines (IL-10) in mouse blood cells by more than 2.5-fold compared with control, with no effect on pro-inflammatory cytokine (TNF-α) production. Pretreating mice with carrageenan once a day before injecting LPS increased the levels of IL-10 by 2.5-fold and reduced TNF-α production by 2-fold compared with control. So, κ/β-carrageenan alone and in combination with LPS enhanced the cellular activity and mobility of peritoneal macrophages by increasing cell adhesion and migration compared with control. LPS activated cells intensively, sometimes resulting in their destruction by necrosis; carrageenan pretreatment reduced the excessive inflammatory cell activation caused by LPS. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1549-1557, 2017.

Accelerated processing of solitary and clustered abasic site DNA damage lesions by APE1 in the presence of aqueous extract of Ganoderma lucidum

The stimulatory effect of the aqueous extract of G. lucidum, a basidiomycetes class fungus in the APE1-enzyme-mediated processing of solitary and bistranded clustered abasic sites DNA damages is presented. Abasic sites are considered the most common type of DNA damage lesions. Our study shows enhanced activity of APE1 in the processing of abasic sites in the presence of the polysaccharides fraction of G. lucidum. Remarkable increase in the amount of single-strand breaks (SSBs) and double-strand breaks (DSBs) from solitary and bistranded clustered abasic sites respectively with APE1 in the presence of the extract was found. This trend is maintained when abasic sites in DNA oligomers are exposed to fibroblast cell extracts in the presence of the extract. While DNA conformational alteration is negligible, APE1 enzyme shows characteristic changes in the alpha helix and beta strand ratio after incubation with G. lucidum extract. The enhanced reactivity of APE1 at the molecular level in the presence of G. lucidium is attributed to this effect. This study potentially amplifies the scope of the use of G. lucidum, which was earlier shown to have only reactive oxygen species (ROS) scavenging properties with regards to DNA damage inhibition.

Tumor-associated macrophages: from basic research to clinical application

The fact that various immune cells, including macrophages, can be found in tumor tissues has long been known. With the introduction of concept that macrophages differentiate into a classically or alternatively activated phenotype, the role of tumor-associated macrophages (TAMs) is now beginning to be elucidated. TAMs act as "protumoral macrophages," contributing to disease progression. TAMs can promote initiation and metastasis of tumor cells, inhibit antitumor immune responses mediated by T cells, and stimulate tumor angiogenesis and subsequently tumor progression. As the relationship between TAMs and malignant tumors becomes clearer, TAMs are beginning to be seen as potential biomarkers for diagnosis and prognosis of cancers, as well as therapeutic targets in these cases. In this review, we will discuss the origin, polarization, and role of TAMs in human malignant tumors, as well as how TAMs can be used as diagnostic and prognostic biomarkers and therapeutic targets of cancer in clinics.

Characterization of Polysaccharides with Antioxidant and Hepatoprotective Activities from the Edible Mushroom Oudemansiella radicata

The preliminary structure, in vitro antioxidant and in vivo hepatoprotective activities of water-soluble polysaccharides (ORWP) and alkali-soluble polysaccharides (ORAP), prepared from the mushroom Oudemansiella radicata, were investigated. Both ORWP and ORAP were heteropolysaccharides with mannose, glucose and galactose being the main monosaccharide components. Regarding the antioxidant activities, ORWP and ORAP showed effective 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity and lipid peroxidation inhibitory effects, as well as moderate reducing power and Fe²⁺ chelating activity. For the hepatoprotective activity, administration of ORWP and ORAP prevented the increase in serum alanine aminotransferase and aspartate aminotransferase activities in a carbon tetrachloride-induced acute liver damage model, suppressed hepatic malondialdehyde formation and stimulated the activities of hepatic superoxide dismutase and glutathione peroxidase. Thus, we speculate that ORWP and ORAP may protect the liver from CCl₄-induced hepatic damage via antioxidant mechanisms.

Radioprotective Effect of Beta D-Glucan and Vitamin E on Gamma Irradiated Mouse

INTRODUCTION

It is shown that beta-D-glucan is an immunologic system booster with radioprotectory effects. Radioprotectors are chemical components that can alleviate biological damage produced by ionizing radiation.

AIM

This study was designed to investigate the synergistic radioprotectory effects of beta-D-glucan and vitamin E on irradiated mice with ⁶⁰Co source.

MATERIALS AND METHODS

A total of 240 female mice were arranged in four, equal population groups of control group (C), treated group with beta D-glucan (G), treated group with vitamin E (E), and treated group with both beta D-glucan and vitamin E (G+E). Each group was divided into three equal population groups of D6, D7 and D8 exposed to ⁶⁰Co radiation with prescribed total body dose of 6, 7 and 8 Gray (Gy), respectively. After the exposure, the number of survived animals was counted by time, then Lethal Dose_50/30 (LD_50/30), Lethal Dose_50/60 (LD_50/60) and Dose Reduction Factor (DRF) were calculated in all groups and corresponding groups.

RESULTS

Based on the results of current study, treatment of the animals with vitamin E did not change values of LD_50/30 and LD_50/60, in comparison to control group. LD_50/30 and LD_50/60 of treated groups with beta D-glucan and beta D-glucan + vitamin E showed significant difference with those of control group (p<0.01). The DRF values in groups E, G and G + E, were calculated respectively as 1, 1.25 and 1.375 based on LD_50/30, and respectively as 1, 1.17 and 1.33 based on LD_50/60. While values of DRF in groups G and G + E showed significant difference in comparison to that of control group (p<0.01), but the difference between DRF of groups G and G + E was not significant (p=0.395).

CONCLUSION

The findings of study obviously showed that, presence of beta D-glucan in the body of mice, during exposure to ionizing radiation, leads to DRF of higher than one, proving the radioprotectory effect of this agent. Also, we demonstrated that, while vitamin E had no radioprotectory effect on irradiated mice, beta D-glucan in combination with vitamin E increased resistance of mice against ionizing radiation.

Agrobacterium sp.-derived β-1,3-glucan enhances natural killer cell activity in healthy adults: a randomized, double-blind, placebo-controlled, parallel-group study

BACKGROUND/OBJECTIVES

The present study investigated the hypothesis that a highly pure linear β-1,3-glucan produced by Agrobacterium sp. R259 enhances human natural killer (NK) cell activity and suppresses pro-inflammatory cytokines.

SUBJECTS/METHODS

In an eight-week, double-blind, randomized, placebo-controlled clinical trial, 83 healthy adults with white blood cell counts of 4,000-8,000 cells/µL were participated and randomly assigned to take two capsules per day containing either 350 mg β-1,3-glucan or placebo. Six participants withdrew their study consent or were excluded due to NK cell activity levels outside the normal range. NK cell activity and serum levels of immunoglobulin G (IgG) and cytokines, such as interferon (IFN)-γ, interleukin (IL)-2, IL-4, IL-6, IL-10, IL-12 and tumor necrosis factor (TNF)-α were measured.

RESULTS

NK cell activity and the serum levels of IL-10 were significantly higher from baseline to week 8 in the β-glucan group compared with the placebo group (P = 0.048, P = 0.029). Consumption of β-1,3-glucan also significantly increased NK cell activity compared with placebo after adjusting for smoking and stress status (P = 0.009). In particular, the effect of β-1,3-glucan on NK cell activity was greater in participants with severe stress than in those experiencing mild stress. However, the administration β-1,3-glucan did not significantly modulate the levels of IFN-γ, IL-2, IL-4, IL-6, IL-12, TNF-α and IgG compared with the placebo.

CONCLUSION

The results showed that supplementation with bacterial β-1,3-glucan significantly increased NK cell activity without causing any adverse effects. Additionally, the beneficial effect of β-1,3-glucan on NK cell activity was greater in participants experiencing severe stress.

N-dihydrogalactochitosan as a potent immune activator for dendritic cells

Immunotherapy has become one of the fastest growing areas of cancer research. A promising in situ autologous cancer vaccine (inCVAX) uses a novel immune activator, N-dihydrogalactochitosan (GC), that possesses the ability to stimulate dendritic cells (DC). inCVAX is a combination treatment procedure involving treatment of the tumor with a thermal near-infrared laser to liberate whole cell tumor antigens, followed by injection of GC (a glucosamine polymer with galactose attached to the amino groups) into the treated tumor thereby inducing a systemic antitumor immune response. Regression of both the treated tumor and distant untreated metastases has been observed in both nonclinical and clinical settings following inCVAX. We studied the stimulatory action of GC on relatively immature DCs (DC2.4 cell line) in vitro. GC at 1 mg/mL was a potent stimulator for DC with limited toxicity, giving increased expression of major histocompatibility complex class 2, CD80, and CD11c. Confocal imaging also revealed qualitatively increased uptake of antigen (Texas red-labeled ovalbumin) by DCs after the introduction of GC. To visualize cellular uptake, GC was conjugated with FITC-fluorophore revealing its cellular internalization after 8 hours. In some cases GC was more effective than the toxic TLR4 agonist, lipopolysaccharide. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 963-972, 2017.

Automated glycan assembly of branched β-(1,3)-glucans to identify antibody epitopes

We report the iterative automated glycan assembly (AGA) and glycan array characterization of conjugation-ready linear and branched β-(1,3)-glucans, a heterogeneous class of carbohydrates with immunomodulatory and anti-tumor effects.

Targeting Myeloid-Derived Suppressor Cells in Cancer

Myeloid derived suppressor cells (MDSC) represent only a minor fraction of circulating blood cells but play an important role in tumor formation and progression. They are a heterogeneous group of cells that influence the tumor microenvironment by depletion of amino acids, oxidative stress, decreased trafficking of antitumor effector cells, and increased regulatory T and regulatory dendritic cell responses. Investigational treatment strategies targeting MDSCs have attempted to inhibit MDSC development and expansion (stem cell factor blockade, modulate of cell signaling, and target MDSC migration and recruitment), inhibit MDSC function (nitric oxide inhibition and reactive oxygen and nitrogen species inhibition), differentiate MDSCs into more mature cells (Vitamins A and D, all-trans retinoic acid, interleukin-2, toll-like receptor 9 inhibitors, taxanes, beta-glucan particles, tumor-derived exosome inhibition, and very small size proteoliposomes), and destroy MDSCs (cytotoxic agents, ephrin A2 degradation, anti-interleukin 13, and histamine blockers). To date, there are no Food and Drug Administration approved therapies selectively targeting MDSCs, but such therapies are likely to be implemented in the future, due to the key role of MDSCs in antitumor immunity.

Extended chain conformation of β-glucan and its effect on antitumor activity

Extended chain conformation of β-glucan visualized by AFM, and its molecular weight- and chain conformation-dependent antitumor activity.

Progress in rigid polysaccharide-based nanocomposites with therapeutic functions

Nanocomposites engineered by incorporating versatile nanoparticles into different bioactive β-glucan matrices display effective therapeutic functions.

Feeding the microbiota-gut-brain axis: diet, microbiome, and neuropsychiatry

The microbial population residing within the human gut represents one of the most densely populated microbial niche in the human body with growing evidence showing it playing a key role in the regulation of behavior and brain function. The bidirectional communication between the gut microbiota and the brain, the microbiota-gut-brain axis, occurs through various pathways including the vagus nerve, the immune system, neuroendocrine pathways, and bacteria-derived metabolites. This axis has been shown to influence neurotransmission and the behavior that are often associated with neuropsychiatric conditions. Therefore, research targeting the modulation of this gut microbiota as a novel therapy for the treatment of various neuropsychiatric conditions is gaining interest. Numerous factors have been highlighted to influence gut microbiota composition, including genetics, health status, mode of birth, and environment. However, it is diet composition and nutritional status that has repeatedly been shown to be one of the most critical modifiable factors regulating the gut microbiota at different time points across the lifespan and under various health conditions. Thus the microbiota is poised to play a key role in nutritional interventions for maintaining brain health.

Uptake of intraperitoneally administrated triple helical β-glucan for antitumor activity in murine tumor models

Triple helical β-glucan (THG) was captured by macrophages and degraded into small fragments to activate neutrophils, leading to apoptosis of tumor cells.

Immunomodulatory Properties of Filamentous Fungi Cultivated through Solid-State Fermentation on Rapeseed Meal

Water extracts from solid-state fermentation (SSF) on rapeseed meal using filamentous fungi exhibit interesting immunomodulatory activities in vitro. Immunomodulation was determined by the capacity of the compounds to activate blood neutrophils and to influence cytokine production in human peripheral blood mononuclear cells (PBMC) and mouse bone marrow-derived macrophages (BMDM). Among the strains tested, Aspergillus sojae mycelium and SSF extracts were the most promising in terms of enhancing the immune response. The filamentous fungus was also successfully cultivated in a pre-pilot bioreactor with forced aeration. The results indicated that the extracts not only activated blood neutrophils but also significantly modulated IL-1β cytokine levels with lipopolysaccharide (LPS)-stimulated PBMC and BMDM without any cytotoxicity in immune cells. IL-1β was down-regulated in a dose-dependent manner in the presence of A. sojae crude mycelium and SSF extract with PBMC, which indicated that there was an anti-inflammatory activity, whereas IL-1β secretion was up-regulated in the presence of stimulated BMDM with the highest concentration that was tested (100 μg/mL). The non-fermented rapeseed had no effect at the same concentration. SSF culture, as a natural product, may be a good source for the development of functional feed with an immunostimulating effect or could potentially be used in medicinal applications.

Antitumoral Effects of D-Fraction from Grifola Frondosa (Maitake) Mushroom in Breast Cancer

D-Fraction is protein-bound β-1,6 and β-1,3 glucans (proteoglucan) extracted from the edible and medicinal mushroom Grifola frondosa (Maitake). The antitumoral effect of D-Fraction has long been exclusively attributed to their immunostimulatory capacity. However, in recent years increasing evidence showed that D-Fraction directly affects the viability of canine and human tumor cells, independent of the immune system. Previously, we have reported that D-Fraction modulates the expression of genes associated with cell proliferation, cell death, migration, invasion, and metastasis in MCF7 human breast cancer cells. Therefore, the purpose of the current study is to investigate if this modulation of gene expression by Maitake D-Fraction really modulates tumor progression. In the present work, we demonstrate for the first time that Maitake D-Fraction is able to act directly on mammary tumor cells, modulating different cellular processes involved in the development and progression of cancer. We demonstrate that D-Fraction decreases cell viability, increases cell adhesion, and reduces the migration and invasion of mammary tumor cells, generating a less aggressive cell behavior. In concordance with these results, we also demonstrate that D-Fraction decreases tumor burden and the number of lung metastases in a murine model of breast cancer.

Physical Interaction of T Cells with Dendritic Cells Is Not Required for the Immunomodulatory Effects of the Edible Mushroom Agaricus subrufescens

Mushrooms are well known for their immunomodulating capacities. However, little is known about how mushroom-stimulated dendritic cells (DCs) affect T cells. Therefore, we investigated the effect of mushroom compounds derived from seven edible mushroom species on DCs, their fate in DCs, and the effect of the mushroom-stimulated DCs on T cells. Each mushroom species stimulated DCs in a different manner as was revealed from the DC’s cytokine response. Assessing DC maturation revealed that only one mushroom species, Agaricus subrufescens, induced complete DC maturation. The other six mushroom species upregulated MHC-II and CD86 expression, but did not significantly affect the expression of CD40 and CD11c. Nevertheless, mushroom compounds of all investigated mushroom species are endocytosed by DCs. Endocytosis is most likely mediated by C-type lectin receptors (CLRs) because CLR binding is Ca²⁺ dependent, and EGTA reduces TNF-α secretion with more than 90%. Laminarin partly inhibited TNF-α secretion indicating that the CLR dectin-1, among other CLRs, is involved in binding mushroom compounds. Stimulated DCs were shown to stimulate T cells; however, physical contact of DCs and T cells is not required. Because CLRs seem to play a prominent role in DC stimulation, mushrooms may function as a carbohydrate containing adjuvant to be used in conjunction with anti-fungal vaccines.

Anti-tumor effects of (1→3)-β-d-glucan from Saccharomyces cerevisiae in S180 tumor-bearing mice

(1→3)-β-d-Glucan from Saccharomyces cerevisiae is a typical polysaccharide with various biological effects and is considered a candidate for the prevention and treatment of cancer in vitro. Research into the function of (1→3)-β-d-glucan in tumor-bearing animals in vivo, however, is limited. Here, we investigated the effects of (1→3)-β-d-glucan from S. cerevisiae on S180 tumor-bearing mice and on the immunity of the tumor-bearing host. The molecular mechanisms underlying the observed effects were investigated. (1→3)-β-d-Glucan was shown to exert anti-tumor effects without toxicity in normal mouse cells. The volume and weight of S180 tumors decreased dramatically following treatment with (1→3)-β-d-glucan, and treatment with the polysaccharide was furthermore shown to increase the tumor inhibition rate in a dose-dependent manner. Spleen index, T lymphocyte subsets (CD₄ and CD₈), as well as interleukins (IL)-2, (IL-2, IL-6), and tumor necrosis factor-α were assayed to detect the immunoregulatory and anti-tumor effects after (1→3)-β-d-glucan intragastrical administration. (1→3)-β-d-Glucan was shown to significantly potentiate the mouse immune responses by, among other effects, decreasing the ratio of CD₄ to CD₈. The expression levels of IL-2, IL-6, and TNF-α were also significantly increased by (1→3)-β-d-glucan. These results suggest that (1→3)-β-d-glucan enhances the host's immune function during the tumor inhibition process. S180 tumor cells treated with (1→3)-β-d-glucan also exhibited significant apoptotic characteristics. (1→3)-β-d-glucan increased the ratio of Bax to Bcl-2 at the translation level by up-regulating Bax expression and down-regulating Bcl-2 expression, resulting in the initiation of cell apoptosis in S180 tumor-bearing mice. Taken together, these results indicate that the anti-tumor effects exerted by (1→3)-β-d-glucan may be attributed to the polysaccharide's immunostimulating properties and apoptosis-inducing features. Further investigation into these properties and their associated mechanisms will contribute to the development of potent polysaccharide-based anti-tumor agents.

Beta-glucan contamination of pharmaceutical products: How much should we accept?

Beta-glucans are large polysaccharides produced by a range of prokaryotic and eukaryotic organisms. They have potential immunostimulatory properties and have been used with therapeutic intent as anti-microbial and anti-tumour agents. A range of other potentially beneficial effects have been described, and oral forms of beta-glucans are widely available over-the-counter and online. Parenteral formulations are popular in parts of Asia and are the subject of ongoing trials, worldwide. Beta-glucans are also potential contaminants of pharmaceutical products, and high levels have been described in some blood products. However, little is known about the clinical effects of such contamination, considerable uncertainty exists over the level at which immunostimulation may occur, and there are no guidelines available on acceptable levels. We encountered beta-glucan contamination of one of our products, and we suspect that others may encounter similar issues since the origin of beta-glucan contamination includes commonly used filters and solutions applied in the manufacture of biotherapeutic agents. It is likely that regulators will increasingly enquire about beta-glucan levels in pharmaceutical products, especially those with an immunomodulatory mechanism of action. Here, we review the literature on beta-glucans in pharmaceutical products and propose an acceptable level for therapeutic agents for parenteral use.

Development of downstream processing to minimize beta-glucan impurities in GMP-manufactured therapeutic antibodies

The presence of impurities or contaminants in biological products such as monoclonal antibodies (mAb) could affect efficacy or cause adverse reactions in patients. ICH guidelines (Q6A and Q6B) are in place to regulate the level of impurities within clinical drug products. An impurity less often reported and, therefore, lacking regulatory guideline is beta-glucan. Beta-glucans are polysaccharides of d-glucose monomers linked by (1-3) beta-glycosidic bonds, and are produced by prokaryotic and eukaryotic organisms, including plants. They may enter manufacturing processes via raw materials such as cellulose-based membrane filters or sucrose. Here we report the detection of beta-glucan contamination of a monoclonal IgE antibody (MOv18), manufactured in our facility for a first-in-human, first-in-class clinical trial in patients with cancer. Since beta-glucans have potential immunostimulatory properties and can cause symptomatic infusion reactions, it was of paramount importance to identify the source of beta-glucans in our product and to reduce the levels to clinically insignificant concentrations. We identified beta-glucans in sucrose within the formulation buffer and within the housing storage buffer of the virus removal filter. We also detected low level beta-glucan contamination in two of four commercially available antibodies used in oncology. Both formulation buffers contained sucrose. We managed to reduce levels of beta-glucan in our product 10-fold, by screening all sucrose raw material, filtering the sucrose by Posidyne® membrane filtration, and by incorporating extra wash steps when preparing the virus removal filter. The beta-glucan levels now lie within a range that is unlikely to cause clinically significant immunological effects. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1494-1502, 2016.

Influence of Saccharomyces boulardii CNCM I-745on the gut-associated immune system

Background

The probiotic Saccharomyces boulardii CNCM I-745 (also known as Saccharomyces cerevisiae HANSEN CBS 5926; in the following S. boulardii) has proven its effectiveness in preventive and therapeutic treatment of many gastrointestinal diseases, especially diseases associated with acute diarrhea. In particular, antibiotic-associated diarrhea, Clostridium difficile-associated diarrhea, traveller’s diarrhea, as well as acute diarrhea due to common viral and bacterial infections in children and adults.

Aim

The aim of this review is to summarize the experimental studies elucidating the molecular and immunological mechanisms by which these clinically proven effects are archived, with an emphasis on the gut-associated immune system. The main focus is laid on anti-inflammatory and immune-modulatory action of S. boulardii involved in bacterial or enterotoxin-mediated diarrhea and inflammation. An attempt is made to differentiate between the effects associated with cellular versus soluble factors and between prophylactic and therapeutic effects.

Methods

A literature search was performed in PubMed/PubMed Central for the effects of S. boulardii on the gut-associated immune system (focus acute diarrhea).

Results and conclusion

S. boulardii exhibits its positive effect by the direct effects on pathogens or their toxins as well as by influencing the host’s infection-induced signaling cascades and its innate and adaptive immune system. The combination of these mechanisms results in a reduction of the pathogens’ ability for adhesion or colonization and an attenuation of the overreacting inflammatory immune response. Thereby, the integrity of the intestinal epithelial cell layer is preserved or restored, and the diarrheic leakage of fluids into the intestinal lumen is attenuated.

Modification of linear (β1→3)-linked gluco-oligosaccharides with a novel recombinant β-glucosyltransferase (trans-β-glucosidase) enzyme from Bradyrhizobium diazoefficiens

Recently, we have shown that glycoside hydrolases enzymes of family GH17 from proteobacteria (genera Pseudomonas, Azotobacter) catalyze elongation transfer reactions with laminari-oligosaccharides generating (β1→3) linkages preferably and to a lesser extent (β1→6) or (β1→4) linkages. In the present study, the cloning and characterization of the gene encoding the structurally very similar GH17 domain of the NdvB enzyme from Bradyrhizobium diazoefficiens, designated Glt20, as well as its catalytic properties are described. The Glt20 enzyme was strikingly different from the previously investigated bacterial GH17 enzymes, both regarding substrate specificity and product formation. The Azotobacter and Pseudomonas enzymes cleaved the donor laminari-oligosaccharide substrates three or four moieties from the non-reducing end, generating linear oligosaccharides. In contrast, the Glt20 enzyme cleaved donor laminari-oligosaccharide substrates two glucose moieties from the reducing end, releasing laminaribiose and transferring the remainder to laminari-oligosaccharide acceptor substrates creating only (β1→3)(β1→6) branching points. This enables Glt20 to transfer larger oligosaccharide chains than the other type of bacterial enzymes previously described, and helps explain the biologically significant formation of cyclic β-glucans in B. diazoefficiens.

Intestinal immunostimulatory activity of neutral polysaccharide isolated from traditionally fermented Korean brown rice vinegar

In this study, diverse intestinal immunostimulatory activities were demonstrated for polysaccharides (KBV-CP) isolated from Korean brown rice vinegar. Monosaccharide composition analysis indicated that KBV-CP was composed mainly of neutral sugar units, primarily glucose and mannose. In vitro, KBV-CP significantly augmented the productions of immunoglobulin A (IgA) and IgA-related cytokines such as interleukin-6 (IL-6) and transforming growth factor-β (TGF-β) in a dose-dependent manner. Furthermore, results of an in vitro co-culture system of intestinal Caco-2 cells and RAW 264.7 macrophage cells suggested that KBV-CP is not only cytotoxic to Caco-2 cells but also capable of being transported across the small intestinal barrier. Oral administration of KBV-CP every other day for 20 days induced the IgA production by Peyer's patch cells as well as in intestinal fluid and fecal extract. In addition, the production of IgA-related cytokines such as TGF-β and IL-6, and granulocyte macrophage colony-stimulating factor was triggered.

Vaccine adjuvants as potential cancer immunotherapeutics

Accumulated evidence obtained from various clinical trials and animal studies suggested that cancer vaccines need better adjuvants than those that are currently licensed, which include the most commonly used alum and incomplete Freund's adjuvant, because of either a lack of potent anti-tumor immunity or the induction of undesired immunity. Several clinical trials using immunostimulatory adjuvants, particularly agonistic as well as non-agonistic ligands for TLRs, C-type lectin receptors, retinoic acid-inducible gene I-like receptors and stimulator of interferon genes, have revealed their therapeutic potential not only as vaccine adjuvants but also as anti-tumor agents. Recently, combinations of such immunostimulatory or immunomodulatory adjuvants have shown superior efficacy over their singular use, suggesting that seeking optimal combinations of the currently available or well-characterized adjuvants may provide a better chance for the development of novel adjuvants for cancer immunotherapy.

Euglena gracilis paramylon activates human lymphocytes by upregulating pro-inflammatory factors

The aim of this study was to verify the activation details and products of human lymphomonocytes, stimulated by different β-glucans, that is Euglena paramylon, MacroGard^®, and lipopolysaccharide. We investigated the gene expression of inflammation-related cytokines and mediators, transactivation of relevant transcription factors, and phagocytosis role in cell-glucan interactions, by means of RT-PCR, immunocytochemistry, and colorimetric assay. Our results show that sonicated and alkalized paramylon upregulates pro-inflammatory factors (NO, TNF-α, IL-6, and COX-2) in lymphomonocytes. A clear demonstration of this upregulation is the increased transactivation of NF-kB visualized by immunofluorescence microscopy. Phagocytosis assay showed that internalization is not a mandatory step for signaling cascade to be triggered, since immune activity is not present in the lymphomonocytes that have internalized paramylon granules and particulate MacroGard^®. Moreover, the response of Euglena β-glucan-activated lymphomonocytes is much greater than that induced by commercially used β-glucans such as MacroGard^®. Our in vitro results indicate that linear fibrous Euglena β-glucan, obtained by sonication and alkaline treatment can act as safe and effective coadjutant of the innate immune system response.

Ergosterol purified from medicinal mushroom Amauroderma rude inhibits cancer growth in vitro and in vivo by up-regulating multiple tumor suppressors

We have previously screened thirteen medicinal mushrooms for their potential anti-cancer activities in eleven different cell lines and found that the extract of Amauroderma rude exerted the highest capacity in inducing cancer cell death. The current study aimed to purify molecules mediating the anti-cancer cell activity. The extract of Amauroderma rude was subject to fractionation, silica gel chromatography, and HPLC. We purified a compound and identified it as ergosterol by EI-MS and NMR, which was expressed at the highest level in Amauroderma rude compared with other medicinal mushrooms tested. We found that ergosterol induced cancer cell death, which was time and concentration dependent. In the in vivo experiment, normal mice were injected with murine cancer cell line B16 that is very aggressive and caused mouse death severely. We found that treatment with ergosterol prolonged mouse survival. We found that ergosterol-mediated suppression of breast cancer cell viability occurred through apoptosis and that ergosterol up-regulated expression of the tumor suppressor Foxo3. In addition, the Foxo3 down-stream signaling molecules Fas, FasL, BimL, and BimS were up-regulated leading to apoptosis in human breast cancer cells MDA-MB-231. Our results suggest that ergosterol is the main anti-cancer ingredient in Amauroderma rude, which activated the apoptotic signal pathway. Ergosterol may serve as a potential lead for cancer therapy.

β-glucan attenuated scopolamine induced cognitive impairment via hippocampal acetylcholinesterase inhibition in rats

β-glucan (polysaccharide) rich diet has been reported to enhance cognition in humans but the mechanism remained elusive. Keeping this in mind, the present study was designed to investigate the interaction of β-glucan with central cholinergic system. Briefly, in-silico analysis revealed promising interactions of β-glucan with the catalytic residues of acetylcholinesterase (AChE) enzyme. In line with this outcome, the in vitro assay (Ellman's method) also exhibited inhibition of AChE by β-glucan (IC50=0.68±0.08μg/µl). Furthermore, the in vivo study (Morris water maze) showed significant dose dependent reversal of the amnesic effect of scopolamine (2mg/kg i.p.) by β-glucan treatment (5, 25, 50 and 100mg/kg, i.p.). Finally, the hippocampi of aforementioned treated animals also revealed dose dependent inhibition of AChE enzyme. Hence, it can be deduced that β-glucan possesses potential to enhance central cholinergic tone via inhibiting AChE enzyme. In conclusion, the present study provides mechanistic insight to the cognition enhancing potential of β-glucan. Keeping in mind its dietary use and abundance in nature, it can be considered as economic therapeutic option against cognitive ailments associated with decline in cholinergic neurotransmission.

Immunomodulatory Activity of Polysaccharide-Protein Complex from the Mushroom Sclerotia of Polyporus rhinocerus in Murine Macrophages

A novel water-soluble polysaccharide-protein complex (PRW1) isolated from the sclerotia of an edible mushroom Polyporus rhinocerus which was purified by membrane ultrafiltration could significantly activate murine macrophages RAW264.7 in vitro. PRW1 had a molecular weight of less than 50 kDa and was found to be a highly branched heteropolysaccharide-protein complex composed of 45.7 ± 0.97% polysaccharide and 44.2 ± 0.41% protein. Based on the results of total acid hydrolysis, methylation analysis, and Fourier transform infrared spectroscopy, the carbohydrate moiety of PRW1 was found to be a β-d-mannoglucan with its backbone containing →1)-d-Glcp-(4→, →1)-d-Glcp-(6→, and →1)-d-Manp-(2→ residues (molar ratio of 5:4:6) and having terminal d-Glcp as side chain (degree of branching of 0.62). In vitro studies showed that PRW1 significantly induced NO production and enhanced the release of a variety of cytokines including G-CSF, GM-CSF, IL-6, IL12p40/70, MCP-1, MCP-5, MIP-1-α, MIP-2, RANTES, sTNFRI, and TNF-α. Mechanistically, PRW1 treatment triggered ERK phosphorylation to activate macrophages within 15 min and significantly increased the expression level of inducible NOS after 6 h. In summary, this study indicates that PRW1 derived from the sclerotia of P. rhinocerus is a potential immunomodulatory agent for cancer immunotherapy.

Tetrandrine suppresses β‑glucan‑induced macrophage activation via inhibiting NF‑κB, ERK and STAT3 signaling pathways

Macrophages are important in inflammation through the production of various proinflammatory mediators. β‑glucan is a polymer of glucose, which is produced by numerous different organisms, including fungi, and acts as a trigger for the induction of inflammatory responses. Tetrandrine (TET), a bis‑benzylisoquinoline alkaloid isolated from the Chinese herb Radix Stephania tetrandra, has been demonstrated to modulate inflammatory responses. In the present study, it was investigated whether TET affects the inflammatory reaction induced by β‑glucan in murine and human macrophages. It was demonstrated that β‑glucan induced the activation of nuclear factor (NF)‑κB and markedly increased the levels of tumor necrosis factor‑α (TNF‑α) and interleukin 1 β (IL‑1β) in macrophages. Treatment with TET resulted in downregulation of phosphorylated NF‑κB p65 and reduction of the production of TNF‑α and IL‑1β. In addition, the phosphorylation of ERK and STAT3 was decreased by TET in activated macrophages. Furthermore, it was demonstrated that the inhibitory effects of TET on β‑glucan‑induced macrophage activation was not due to its cytotoxic action. Conclusively, these results indicate that TET can decrease the inflammatory responses mediated by β‑glucan in macrophages. Thus, TET may serve as an effective tool for the treatment of β‑glucan‑associated inflammatory diseases.

Recognition of purified beta 1,3/1,6 glucan and molecular signalling in the intestine of Atlantic salmon

Atlantic salmon was orally intubated with a highly purified β-glucan product (MacroGard(®)) to study the recognition of the molecule by the receptor genes, the regulation of the downstream signalling genes and global proteins, and the micromorphological changes in the intestine. The β-glucan receptor genes of Atlantic salmon, sclra, sclrb, sclrc and cr3, seem to recognize the molecule, and initiate the downstream ITAM-motif signalling, as evident from the significantly high mRNA levels of ksyk, mapkin2, il1b and mip2a levels. Among the altered proteins, the Apoa4 (involved in carbohydrate and lipid metabolism); Tagln, Actb (uptake of β-glucan); Psma2 (associated with substrate recognition); and Ckt (energy metabolism-related) were the overexpressed ones. The underexpressed proteins included the Uk114, Rpl9, Ctsb and Lgal that are connected to proliferation, LPS-stimulation, Il1b and lactose recognition, respectively. Furthermore, the mRNA levels of igt and the number of immune cells in the distal intestine were found to increase upon β-glucan uptake by the fish. This study provides some clues on the mechanisms by which the β-glucan evokes response in Atlantic salmon, particularly at the intestinal level.

Structural characterization and immunomodulatory activity of a new heteropolysaccharide from Prunella vulgaris

A new heteropolysaccharide, here called P1, was isolated from the fruit clusters of Prunella vulgaris using a hot water extraction method. Chemical and physical analyses indicated that P1 had a spherical conformation with an average molecular weight of 1750 kDa and consisted of arabinose (28.37%), xylose (54.67%), mannose (5.61%), glucose (5.46%), and galactose (5.89%). The main types of P1 linkages were proved to be (1→5)-linked α-L-Ara, (1→)-linked α-L-Ara, (1→3)-linked α-D-xyl, (1→3)-linked β-D-Gal, (1→3,6)-linked β-D-Gal, (1→3,6)-linked α-D-Man and (1→6)-linked α-D-Glc according to the periodate oxidation-Smith degradation and NMR analyses. P1 could significantly enhance the secretion of NO, TNF-α, and IL-6 in murine RAW 264.7 cells, involving the toll-like receptor 2 (TLR2), TLR4 and complement receptor 3 (CR3). Further studies showed that P1 exhibited stable immune activities in the pH range of 4.0-10.0 and below 121 °C. The results suggested that P1 could be used as a potent immunomodulatory agent in functional foods and pharmacological fields.