Type II arabinogalactan from Anoectochilus formosanus induced dendritic cell maturation through TLR2 and TLR4

Combining cashew gum with cyclophosphamide in murine melanoma model: A strategy for the reduction of side effects

The understanding of cancer immunity and antitumor factors generated by natural polysaccharides is not yet fully comprehended. Polysaccharides, like cashew gum (CG), can exhibit immunomodulatory action and may assist in the antitumor process and side effects relieve. This study aimed to determine the antitumor effect of CG alone or in combination with cyclophosphamide (CTX), and its interactions with immune cells, in a murine melanoma model, using the B16-F10 cell line. Tumor growth inhibition, hematological, histopathological, ELISA, flow cytometry, immunofluorescence, and qRT-PCR analyses were performed to elucidate the antitumor potential, involvement of immune cells, and potential toxic effects. CG showed significant tumor growth inhibition, reaching up to 42.9 % alone and 51.4 % in combination with CTX, with mild toxicity to organs. CG enhanced leukocyte count, even in the presence of CTX. Furthermore, CG influenced the activation of tumor-associated macrophages (TAM), characterized by an increase in Il4, as well as a reduction in Ifng, Il1b, Tgfb, and Il6 gene expression. Nevertheless, these effects did not compromise the antitumor activity of CG. In summary, the combination of CG with CTX is a promising approach for leukopenia, one of the most important side effects of cancer treatment and deserves further investigation.

β-1,4-Galactan suppresses lipid synthesis in sebaceous gland cells via TLR4

Sebum is a lipid mixture secreted from sebaceous glands of the skin. The excessive secretion of sebum causes acne vulgaris and seborrheic dermatitis, while its deficiency causes xerosis. Therefore, the appropriate control of sebum secretion is crucially important to keep the skin healthy. In the present study, we evaluated the effects of naturally occurring polysaccharides on lipid biosynthesis in hamster sebaceous gland cells. Among the tested polysaccharides, β-1,4-galactan, the main chain of type I arabinogalactan, most potently suppressed lipid synthesis in the sebaceous gland cells as analysed by oil red O staining. Toll-like receptor (TLR)4 inhibitors counteracted this suppressive effect and lipopolysaccharide, a TLR4 ligand, mimicked this effect, suggesting the involvement of the TLR4 signalling pathway. In the cells β-1,4-galactan significantly decreased mRNA levels of lipogenesis-related transcription factors (peroxisomeGraphical Abstract$\includegraphics{\bwartpath }$ proliferator-activated receptor γ and sterol regulatory element-binding protein 1) and enzymes (acetyl-CoA carboxylase and fatty acid synthase) as well as the glucose transporter GLUT4. Furthermore, β-1,4-galactan increased the production of lactic acid serving as a natural moisturizing factor and enhanced the proliferation of sebaceous gland cells. These results suggest potential of β-1,4-galactan as a material with therapeutic and cosmetic values for the skin.

Plants arabinogalactans: From structures to physico-chemical and biological properties

Arabinogalactans (AGs) are plant heteropolysaccharides with complex structures occasionally attached to proteins (AGPs). AGs in cell matrix of different parts of plant are freely available or chemically bound to pectin rhamnogalactan. Type I with predominantly β-d-(1 → 4)-galactan and type II with β-d-(1 → 3) and/or (1 → 6)-galactan structural backbones construct the two main groups of AGs. In the current review, the chemical structure of AGs is firstly discussed focusing on non-traditional plant sources and not including well known industrial gums. After that, processes for their extraction and purification are considered and finally their techno-functional and biological properties are highlighted. The role of AG structure and function on health advantages such as anti-tumor, antioxidant, anti-ulcer- anti-diabetic and other activites and also the immunomodulatory effects on in-vivo model systems are overviewed.

Brassica rapa L. activates macrophages via Toll-like receptors

Macrophages can initiate innate immune responses against microbes and cancer. The aim of this study was to elucidate the effects of Brassica rapa L. on macrophages. The production of interleukin (IL)-6, tumor necrosis factor (TNF)-α, and interferon-γ induced by the insoluble fraction of B. rapa L. was decreased in macrophage-depleted spleen cells compared with controls. The insoluble fraction of B. rapa L. induced expression of H-2Kb, I-Ab, CD40, and CD86, production of cytokines and nitric oxide, and phagocytic activity in RAW264 cells. After treatment with the insoluble fraction, IL-6 and TNF-α production was significantly decreased by anti-Toll-like receptor (TLR)2 mAb or polymyxin B compared with the control. Furthermore, insoluble fraction-mediated cytokine production was significantly lower in peritoneal macrophages from TLR2-/- and TLR4-/- mice compared with wild-type mice. These results suggest that B. rapa L. is a potentially effective immunomodulator for activating macrophages to prevent infections.

Biologically active polysaccharide from edible mushrooms: A review

Mushrooms are renewable natural gift for humankind, furnished with unique taste, flavor and medicinal properties. For the last few decades study of mushroom polysaccharides has become a matter of great interest to the researchers for their immunomodulating, antimicrobial, antioxidant, anticancer, and antitumor properties. Molecular mass, branching configuration, conformation of polysaccharides and chemical modification are the major factors influencing their biological activities. The mechanism of action of mushroom polysaccharides is to stimulate T-cells, B-cells, natural killer cells, and macrophage dependent immune responses via binding to receptors like the toll-like receptor-2, dectin-1. The present review offers summarized and significant information about the structural and biological properties of mushroom polysaccharides, and their potential for development of therapeutic materials.

Immune-Enhancing Activity of Aqueous Extracts from Artemisia rupestris L. via MAPK and NF-kB Pathways of TLR4/TLR2 Downstream in Dendritic Cells

Artemisia rupestris L. has long been used as a traditional herbal medicine owing to its immunomodulatory activity. Aqueous extracts of Artemisia rupestris L. (AEAR) contain the main functional component and can activate the maturation of dendritic cells (DCs) and enhance the adaptive immunity as the adjuvant against infections. To explore the underlying mechanism of immunomodulatory activities of AEAR, DCs were produced from bone-marrow cells of mice and the effects of AEAR on cell viability were assessed by the Cell Counting Kit 8 (CCK8) method and annexin V/propidium iodide staining assays. Then, the effects of AEAR on the morphology, maturation, and function of DCs were detected using a microscope, flow cytometry-based surface receptor characterization, and endocytosis assays. The secretion levels of cytokines were then analyzed with enzyme-linked immunosorbent assay (ELISA). The activation state of DCs was evaluated by the mixed lymphocyte reaction (MLR). The activity of MAPKs and NF-κB pathways, which were involved in the regulation of AEAR on DCs, was further detected by Western blot. AEAR did not have a cytotoxic effect on DCs or mouse splenocytes. AEAR remarkably enhanced the phenotypic maturation of DCs and promoted the expression of costimulatory molecules and the secretion of cytokines in DCs. AEAR also significantly decreased the phagocytic ability of DCs and augmented the abilities of DCs to present antigens and stimulate allogeneic T-cell proliferation. Simultaneously, AEAR potently activated toll-like receptor (TLR)4-/TLR2-related MAPKs and induced the degradation of IκB and the translocation of NF-κB. In short, AEAR can profoundly enhance the immune-modulating activities of DCs via TLR4-/TLR2-mediated activation of MAPKs and NF-κB signaling pathways and is a promising candidate immunopotentiator for vaccines.

The purification, structural characterization and antidiabetic activity of a polysaccharide from Anoectochilus roxburghii

Anoectochilus roxburghii, a traditional Chinese medicinal herb, has been widely used for treating numerous chronic diseases.

Dietary Fiber Pectin Ameliorates Experimental Colitis in a Neutral Sugar Side Chain-Dependent Manner

Dietary fiber, with intake of soluble fibers in particular, has been reported to lower the risk for developing inflammatory bowel diseases (IBD). This is at least partly attributable to the fermentation of dietary fiber by the colonic microbiota to produce short chain fatty acids. Pectin, a widely consumed soluble fiber, is known to exert a protective effect in murine models of IBD, but the underlying mechanism remains elusive. Apart from having a prebiotic effect, it has been suggested that pectin direct influences host cells by modulating the inflammatory response in a manner dependent on its neutral sugar side chains. Here we examined the effect of the side chain content of pectin on the pathogenesis of experimental colitis in mice. Male C57BL/6 mice were fed a pectin-free diet, or a diet supplemented with characteristically high (5% orange pectin) or low (5% citrus pectin) side chain content for 10-14 days, and then administered 2,4,6-trinitrobenzene sulfonic acid or dextran sulfate sodium to induce colitis. We found that the clinical symptoms and tissue damage in the colon were ameliorated in mice that were pre-fed with orange pectin, but not in those pre-fed with citrus pectin. Although the population of CD4⁺Foxp⁺ regulatory T cells and CD4⁺RORγt⁺ inflammatory T cells in the colon were comparable between citrus and orange pectin-fed mice, colonic interleukin (IL)-1β and IL-6 levels in orange pectin-fed mice were significantly decreased. The fecal concentration of propionic acid in orange pectin-fed mice was slightly but significantly higher than that in control and citrus pectin-fed mice but the cecal concentration of propionic acid after the induction of TNBS colitis was comparable between orange and citrus pectin-fed mice. Furthermore, the protective effect of orange pectin against colitis was observed even in mice treated with antibiotics. IL-6 production from RAW264.7 cells stimulated with the toll-like receptor agonist Pam3CSK4 or lipopolysaccharide was suppressed by pre-treatment with orange pectin in vitro. Taken together, these results suggest that the side chains of pectin not only augment prebiotic effects but also directly regulate IL-6 production from intestinal host cells in a microbiota-independent fashion to attenuate colitis.

Anti-cervical carcinoma effect of Portulaca oleracea L. polysaccharides by oral administration on intestinal dendritic cells

BACKGROUND

Cervical cancer is the second most prevalent cancer worldwide. Portulaca oleracea L. polysaccharide (POL-P3b) has been found to have enhancing immune and anti-cervical cancer activity by oral administration. Dendritic cells (DC) play a key roles in regulating intestinal immune homeostasis. In this study, we analyzed the inhibition apoptosis effects of POL-P3b on intestinal DC and relevant mechanisms.

METHODS

Intestinal DC was isolated from U14-bearing mice treated with POL-P3b (50 mg/kg, 100 mg/kg and 200 mg/kg, respectively). The effects of POL-P3b on proliferation and inhibiting apoptosis in intestinal DC were evaluated by MTT assay, Hoechst 33342 and Annexin V-FITC/PI staining. Mitochondrial Ca²⁺ was analyzed using flow cytometry instrument. The potential mechanisms underlying POL-P3b-induced protection of intestinal DC from cervical cancer-induced apoptosis were detected with Western blotting evaluation of expression levels of TLR4 and relevant proteins for apoptotic signaling pathway.

RESULTS

We found that a large number of intestinal DC were apoptosis in U14-bearing mice. Treatment with POL-P3b in U14-bearing mice at different doses for 12 d resulted in a significant increase in intestinal DC survival, and the mechanisms were related to inhibiting DC apoptosis.

CONCLUSION

Our results suggested that POL-P3b-induced protection against tumor-induced intestinal DC apoptosis through stimulating the TLR4-PI3K/AKT-NF-κB signaling pathway. This study enhanced understanding of the oral administration with POL-P3b exerted on anti-tumor activity and its action mechanism.

A 3-O-methylated heterogalactan from Pleurotus eryngii activates macrophages

Mushroom-derived polysaccharides exhibit various biological activities owing to their diverse structural features. Here, we purified a 3-O-methylated heterogalactan (WPEP-N-b, Mw 21.4 kDa) from the fruiting bodies of Pleurotus eryngii. WPEP-N-b is composed primarily of galactose (43.8%), mannose (39.3%), methyl-galactose (11.7%) and glucose (9.2%) residues, with the main chain being composed of α-1,6-linked D-Galp and 3-O-Me-D-Galp, branched at O-2 with single t-β-D-Manp as major the side chain. β-1,6-D-Glcp residues are present as minor components either in side-chains or backbone. WPEP-N-b increases macrophage phagocytosis and secretion of NO, TNF-α, IL-6 and IL-1β. Mechanistic studies demonstrate that WPEP-N-b promotes the degradation of IκB-α, and enhances phosphorylation of MAPKs and the NF-κB p65 subunit. Our results also indicate that this polysaccharide activates RAW264.7 cells via MAPK and NF-κB signaling pathways and the Toll-like receptor 2(TLR2). These results increase our understanding as to how mushroom-derived polysaccharides modulate the immunologic process.

A homogalacturonan from Hippophae rhamnoides L. Berries enhance immunomodulatory activity through TLR4/MyD88 pathway mediated activation of macrophages

Our previous study isolated a natural high-methoxyl homogalacturonan (HRWP-A) from Hippophae rhamnoides and showed antitumor activity in vivo. In this study, the immunomodulatory activity and mechanisms of action of HRWP-A were further investigated. Results showed that HRWP-A could recover the body condition and activated macrophage in Cyclophosphamide (CTX)-induced immunosuppressed mice. Further, we investigated the possible mechanism underlying the effects of HRWP-A on mouse peritoneal macrophages. qPCR and western blot revealed that HRWP-A upregulated the expression of TLR4 mRNA in vitro. This process was accompanied by a clear increase in MyD88 expression and p-IκB-α, but these effects were largely abrogated by pretreatment with anti-TLR4 antibodies. The effects of HRWP-A on macrophage NO, IL-1β and IL-6 production were also inhibited by anti-TLR4 antibodies and were greatly influenced by the NF-κB inhibitor PDTC. Moreover, HRWP-A failed to induce the production of NO, IL-1β and IL-6 in peritoneal macrophages prepared from C3H/HeJ mice, which have a point mutation in the Tlr4 gene, suggesting the involvement of the TLR4 molecule in HRWP-A-mediated macrophage activation. These results may have important implications for our understanding of the structure-activity relationship of immunopotentiating polysaccharides from medicinal herbs.

Lectin microarray analysis of isolated polysaccharides from Sasa veitchii

We report lectin microarray profile of the polysaccharide fraction derived from Sasa veitchii leaf that exhibits anti-influenza activity. This fraction showed higher reactivities with lectins known as binders to oligo-mannose, fucose, or galactose. Our findings along with previously reported monosaccharide components suggest that the polysaccharide can be cross-reactive with cell surface receptors involved in immune system, thereby exerting anti-influenza activity.