Immunomodulatory activity of polysaccharides isolated from Strongylocentrotus nudus eggs

A homologous series of α-glucans from Hemicentrotus pulcherrimus and their immunomodulatory activity

Seven macromolecular polysaccharides (HPP-2S-HPP-8S) were purified from the gonads of sea urchin Hemicentrotus pulcherrimus. They were characterized as α-glucan homologues, sharing the same α-1,4-glucan backbone substituted at C-6 positions by glucose with HPP-1S that occurs as the major polysaccharide in H. pulcherrimus, while with higher degrees of branching, and additionally possessing minor amounts of mannose and ribose. The branching degree and amounts of non-glucose branches showed a generally increasing tendency across HPP-2S - HPP-8S. These polysaccharides exhibited significant macrophage-activating effects by augmenting the secretion of NO, TNF-α and IL-6, which probably involves the activation of NF-κB and MAPKs signaling pathways. Notably, the polysaccharides with a higher degree of branching exhibited markedly enhanced immunomodulatory capacity with a lowest effective concentration of 1.95 μg/mL. This work provides new cases of bioactive α-glucans and reveals their potential application as immunomodulating agents.

Antitumor immunostimulatory activity of the traditional Chinese medicine polysaccharide on hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignancy, often associated with compromised immune function in affected patients. This can be attributed to the secretion of specific factors by liver cancer cells, which hinder the immune response and lead to a state of immune suppression. Polysaccharides derived from traditional Chinese medicine (TCM) are valuable constituents known for their immunomodulatory properties. This review aims to look into the immunomodulatory effects of TCM polysaccharides on HCC. The immunomodulatory effects of TCM polysaccharides are primarily manifested through the activation of effector T lymphocytes, dendritic cells, NK cells, and macrophages against hepatocellular carcinoma (HCC) both in vivo and in vitro settings. Furthermore, TCM polysaccharides have demonstrated remarkable adjuvant antitumor immunomodulatory effects on HCC in clinical settings. Therefore, the utilization of TCM polysaccharides holds promising potential for the development of novel therapeutic agents or adjuvants with advantageous immunomodulatory properties for HCC.

Strongylocentrotus nudus egg polysaccharide (SEP) suppresses HBV replication via activation of TLR4-induced immune pathway

Chronic hepatitis B virus (HBV) infection is a worldwide public health problem that causes significant liver-related morbidity and mortality. In our previous study, Strongylocentrotus nudus eggs polysaccharide (SEP), extracted from sea urchins, had immunomodulatory and antitumor effects. Whether SEP has anti-HBV activity is still obscure. This study demonstrated that SEP decreased the secretion of hepatitis B surface antigen (HBsAg) and e antigen (HBeAg), as well as the replication and transcription of HBV both in vitro and in vivo. Immunofluorescence and immunohistochemistry results showed that the level of HBV core antigen (HBcAg) was clearly reduced by SEP treatment. Mechanistically, RT-qPCR, western blot, and confocal microscopy analysis showed that SEP significantly increased the expression of toll-like receptor 4 (TLR4) and co-localization with TLR4. The downstream molecules of TLR4, including NF-κb and IRF3, were activated and the expression of IFN-β, TNF-α, IL-6, OAS, and MxA were also increased, which could suppress HBV replication. Moreover, SEP inhibited other genotypes of HBV and hepatitis C virus (HCV) replication in vitro. In summary, SEP could be investigated as a potential anti-HBV drug capable of modulating the innate immune.

Polysaccharide from Strongylocentrotus nudus eggs regulates intestinal epithelial autophagy through CD36/PI3K-Akt pathway to ameliorate inflammatory bowel disease

Sea urchin is a popular food all over the world, of which eggs are main edible part. Previous studies suggested that polysaccharides from eggs of Strongylocentrotus nudus (SEP) exhibited immunomodulatory activities during anti-tumor therapy, nevertheless, effects of SEP on inflammatory bowel disease and its underlying mechanisms have never been reported. In the present study, we showed that the SEP inhibited dextran sodium sulfate-induced ulcerative colitis characterized by decreased disease activity index, restored colon length and body weight, improved histopathological changes, down-regulation of inflammatory cytokines levels and Th17/Treg ratios in C57BL/6 J mice. Moreover, immunofluorescence analysis suggested that SEP repaired gut barrier in UC mice, while 16S rDNA sequencing exhibited improved intestinal flora. Mechanistically, we found SEP significantly modulated autophagy-related factors in intestinal epithelial cells (IECs), while might contributed to pathogenesis of UC. Furthermore, we demonstrated PI3K/Akt pathway was involved in regulatory effect of SEP on lipopolysaccharide-induced autophagy of HT-29 cells. Besides, among possible polysaccharide binding receptors, change of the CD36 expression was most significant, which was associated with PI3K/Akt signals. Collectively, our study showed for the first time that the SEP might be used a prebiotic agent to improve IBD through regulating CD36-PI3K/Akt mediated autophagy of IECs.

Pharmacokinetic study of Strongylocentrotus nudus egg polysaccharide in rats and beagles using a 3H-labeling method

Strongylocentrotus nudus egg polysaccharide (SEP) extracted from sea urchins has potential anticancer activity. However, little is known about its pharmacokinetic properties. To investigate the pharmacokinetics of SEP, it was radiolabeled with tritium. Furthermore, a sensitive, selective, and rapid liquid scintillation counter (LSC) method for quantifying ³H-SEP in biological matrix was validated. The lower quantification limit of the method was 4 Bq. The relative standard deviations (RSDs) of the intra- and inter-day precision were <3.0% and <3.9%, respectively. ³H-SEP was successfully applied to investigate the pharmacokinetics of SEP after intravenous administration of 20, 40, and 80 mg/kg (40 μCi/kg) in rats and 5, 10, and 20 mg/kg (6 μCi/kg) in beagles. The AUC_(0-t) of SEP at three different doses was 487.81 ± 39.99 mg/L*h, 1,003.10 ± 95.94 mg/L*h, and 2,188.84 ± 137.73 mg/L*h in rats and 144.12 ± 3.78 mg/L*h, 322.62 ± 28.03 mg/L*h, and 754.17 ± 37.79 mg/L*h in beagles. The terminal elimination half-life (t_1/2) of SEP was longer in beagles (204.29 ± 139.34 h) than in rats (35.48 ± 6.04 h). The concentration of SEP in plasma declined rapidly in both rats and beagles. All the study results provide detailed pharmacokinetic profiles of SEP in two kinds of animals, which will be helpful for further development.

Gaz Alafi: A Traditional Dessert in the Middle East With Anticancer, Immunomodulatory, and Antimicrobial Activities

Background

From the earliest times, manna has been widely used as a tasty local sweet or folk medicine. The type of manna being investigated in the present study is called Gaz-alafi, a mixture of insect and Quercus brantii leaves secretions from oak forests in the north of Iraq and west of Iran.

Methods

Aqueous and ethanol extracts were prepared as decoction. Various phytochemical tests were conducted to analyze manna composition, including total phenolic contents using the Folin-Ciocalteu method and LC-MS. Gallic acid and catechin were detected in both extracts, in addition to tiliroside presence in ethanol extract, which added more value to the phenolic content of ethanol extract. Cytotoxic activities of Gaz alafi were evaluated against breast cancer cell lines and compared to normal cell lines and doxorubicin using the MTT assay. Antimicrobial properties were assessed against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, and Candida albicans using the dilution method of the micro-titer plate. Serum levels of IFN-γ, interleukin-2 (IL-2), interleukin-4 (IL-4), and interleukin-10 (IL-10) were measured using ELISA. The effect of extracts on splenocyte proliferation was evaluated using the lymphocytes proliferation assay. Macrophage function was evaluated using the nitro blue tetrazolium assay, whereas pinocytosis was evaluated using the neutral red uptake assay. Ten days after tumor inoculation, changes in tumor size, survival rates, levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatinine were measured.

Results

The growth of cancer cells was inhibited by Gaz alafi ethanol extract. An alteration in IFN- γ, IL-2, and IL-4 levels toward antiproliferation immune response were reported for both extracts. The aqueous extract efficiently stimulated lymphocyte proliferation, phagocytosis, and pinocytosis, followed by the ethanol extracts with moderate activity. After treating the mice with ethanol extracts, a significant reduction in tumor size and several undetected tumors were recorded.

Conclusions

Gaz alafi extracts (aqueous and ethanol) are promising sources for anticancer and immunostimulatory agents. Further studies are needed to fully identify the chemical composition of Gaz alafi extracts.

Strongylocentrotus nudus Eggs Polysaccharide Enhances Macrophage Phagocytosis Against E.coli Infection by TLR4/STAT3 Axis

Antibiotics resistance is one of the most significant public health threats globally. Strategies that strengthen host defenses to control pathogen infection has become a hot research field. Macrophages are part of early host defense mechanisms, and are activated via host pattern recognition receptors (PRRs), such as Toll-like receptor 4 (TLR4), which then facilitates phagocytosis and elimination of invading pathogens. However, few activators of PRRs have been approved for clinical use because of their toxic effects. This study aimed to investigate whether Strongylocentrotus nudus eggs polysaccharide (SEP), a non-toxic extract from seafood, contributes to host defense against bacterial infection. Results showed that SEP promoted bacterial clearance by enhancing phagocytosis by macrophages during E. coli infection in vitro, but was inhibited by TLR4 specific inhibitor TAK-242, STAT3 inhibitor Stattic or blockade of CD64. In addition, SEP protected mice from E. coli induced mortality, reduced pulmonary inflammation and inhibited dissemination of bacteria to organs, while TAK-242 retarded the protection of SEP. Overall, SEP strengthened innate host defense and improved the outcome in bacterial infection, suggesting that SEP could be used as a potential immunomodulator in host-directed therapies.

Immunomodulatory Activity of Carboxymethyl Pachymaran on Immunosuppressed Mice Induced by Cyclophosphamide

The effects of immunomodulatory activity of two types of carboxymethyl pachymaran (CMP-1 and CMP-2) on cyclophosphamide (CTX)-induced mice were investigated. Both CMP-1 and CMP-2 were found to restore the splenomegaly and alleviate the spleen lesions and the mRNA expressions of TLR4, MyD88, p65 and NF-κB in spleen were also increased. CMP-1 and CMP-2 could enhance the immunity by increasing the levels of TNF-α, IL-2, IL-6, IFN-γ, Ig-A and Ig-G in serum. In addition, CMP-1 could increase the relative abundance of Bacteroidetes and reduce the relative richness of Firmicutes at the phylum level. CMP-1 and CMP-2 could reduce the relative abundance Erysipelatoclostridum at the genus level. CMP-1 and CMP-2 might enhance the immune function of immunosuppression mice by regulating the gene expression in the TLR4/NF-κB signaling pathway and changing the composition and abundance of the intestinal microbiota. The results suggested that CMP-1 and CMP-2 would be as potential immunomodulatory agents in functional foods.

Structural characterization and immunostimulatory activity in vitro of a glycogen from sea urchin-Strongylocentyotus internedius

Sea urchin possesses both high nutritional and medicinal value. It contains diverse biological active polysaccharides. But there are few studies on its glycogen. In the current study, a glucan (MSGA) was separated from Strongylocentyotus internedius and purified by ion exchange and gel filtration column. Chemical analysis revealed that MSGA with 2.65 × 10⁷ Da is made up entirely of glucose. The analysis of methylation, NMR and mass spectrum demonstrated that MSGA is a highly branched glycogen with α-(1→4) linked gluconic backbone and branched at C-6 (one branch per five residues). In addition, MSGA showed good in vitro immunostimulatory activity via NF-κB and MAPKs pathways. It is considered that high degree of branching is necessary for its activity. However, the relationship between structure and immunostimulatory activity of natural glycogens is difficult to elucidate because the difference in their structural properties. Therefore, much more research is needed in this area.

Strongylocentrotus nudos Egg Polysaccharide induces autophagy and apoptosis in leukaemia cells by regulating mitochondrial function

In this study, we investigated the ability of the Polysaccharide from the Eggs of Strongylocentrotus nudus (SEP) to regulate cellular autophagy and apoptosis in leukaemia cells. Human acute myeloid leukaemia (AML) cells (HL60) and murine AML cells (L1210) treated with SEP were used to assess viability using Cell Counting Kit‐8, cytotoxicity by measuring lactate dehydrogenase release, the generation of reactive oxygen species (ROS) by DCFH‐DA staining. In addition, we utilized a mouse model of leukaemia in which L1210 cells were injected into DBA/2 mice by sub‐axillary injection. Treatment with SEP decreased cell viability, increased in cytotoxicity and increased the release of ROS in a dose‐dependent manner. SEP treatment was also associated with the activation of pro‐apoptotic proteins cleaved caspase‐3, cleaved caspase‐9 and cleaved poly (ADP‐ribose) polymerase (PARP). Activation of the apoptotic pathway led to the release of cytochrome C (CytoC) into the cytosol of the cell resulting in decreased membrane potential. The effect of SEP treatment was depended on the activation of the nuclear factor kappa‐B (NF‐κB) signalling pathway as SEP treatment led to an increase in NF‐κB phosphorylation, and inhibition of NF‐κB signalling using PDTC blocked SEP‐mediated activation of apoptosis. Treatment with SEP also prolonged survival time in our leukaemia mouse model and was associated with diminished tumour volume, increased leucocyte and lymphocyte proliferation, promoted pro‐inflammatory factor release in serum and enhanced immune function. Taken together, these data suggest that SEP inhibits the progression of leukaemia by initiating mitochondrial dysfunction, autophagy, and apoptosis via the NF‐κB signalling pathway.

Immunomodulatory Activity in vitro and in vivo of Polysaccharides from Kabuli Chickpea (Cicer arietinum L.) Hull

Research background

Polysaccharides isolated from plants, fungi and bacteria are associated with immunomodulatory effects. Chickpea hull, which is regarded as food industrial waste, contains considerable amount of antioxidants and bioactive compounds.

Experimental approach

In the present study, we investigated the immunomodulatory activity of polysaccharides from kabuli chickpea (Cicer arietinum L.) hull (CHPS). In vitro study was conducted with RAW264.7 cell line while in vivo study was carried out using specific pathogen-free BALB/c mouse animal model.

Results and discussion

In in vitro test with RAW264.7 murine macrophage cells, the three purified fractions of chickpea hull polysaccharides showed potent immunomodulatory activity. Sample CHPS-3 showed stronger effect on cell viability, promoted the phagocytosis index to a greater extent and had the best effect on acid phosphatase activity. Moreover, it was found that CHPS-3 significantly (p<0.05) enhanced the secretion of nitrogen monoxide and cytokine (interleukins IL-6, IL-1β and tumor necrosis factor-alpha (TNF-α)) levels. In in vivo study, CHPS-3 improved thymus and spleen indices in cyclophosphamide-induced immunodeficient mice. Increased activities of lysozyme, catalase, superoxide dismutase and glutathione peroxidase, serum haemolysin content and total antioxidant capacity were observed, while the amount of malondialdehyde in the liver decreased.

Novelty and scientific contribution

The results suggest that chickpea hull polysaccharides enhanced the immune activity and could be developed as the ingredient of functional foods.

Suitability evaluation on material specifications and edible methods of Dendrobii Officinalis Caulis based on holistic polysaccharide marker

Background

Dendrobii Officinalis Caulis (DC) is a well-known tonic herbal medicine worldwide and has favorable immunomodulatory activity. Various material specifications of DC are available in herbal markets, and DC is ingested by different edible methods. However, whether these specifications and edible methods are suitable or not remains unknown.

Methods

In this study, we evaluated the suitability of four material specifications (fresh stem, dried stem, fengdou and powder) and three edible methods (making tea, soup and medicinal liquor) based on holistic polysaccharide marker (HPM), the major polysaccharide components in DC. First, the HPMs were extracted from the four specifications of DC by the three edible methods in different conditions. Second, qualitative and quantitative characterization of the extracted HPMs was performed using high performance gel permeation chromatography (HPGPC). Third, immunomodulatory activities of the extracted HPMs were evaluated in vivo.

Results

The results showed that the HPMs were found to be quantitatively different from various specification of DC and edible methods. In vivo analysis indicated that the HPMs exerted positive effects on innate immune responses by increment in proliferation of splenocytes, secretion of IL-2 and cytotoxicity activity of NK cells. Moreover, the dosage amount of HPM should be defined as a certain range, but not the larger the better, for exerting strong immunological activities.

Conclusion

According to the both chemical and biological results, fengdou by boiling with water for 4 h is the most recommended specification and edible method for DC.

Modulating effects of polysaccharides from the fruits of Lycium barbarum on the immune response and gut microbiota in cyclophosphamide-treated mice

In the present study, the effects of Lycium barbarum polysaccharides (LBPS) on immunoregulation and gut microbiota dysbiosis in cyclophosphamide (CTX)-induced mice were investigated to elucidate whether the attenuation of immunosuppression is related to the modulation of the gut microbiota. The results showed that administration of LBPS could protect immune organs (enhancing immune organ indexes and alleviating immune organ damage), enhance the production of immune-related cytokines (IL-2, IL-6, IL-1β, TNF-α and IFN-γ) and prevent the hepatotoxicity in CTX-induced mice. Additionally, LBPS treatment could promote the production of short-chain fatty acids and modulate the composition of the gut microbiota, increasing the relative abundances of Bacteroidaceae, Lactobacillaceae, Prevotellaceae and Verrucomicrobiaceae, which were positively associated with immune traits. The present results indicated that LBPS might regulate the immune response depending on the modulation of the gut microbiota, suggesting that LBPS could be developed as special ingredients for immunoregulation in association with the modulation of the gut microbiota.

Methods of extraction, separation, purification, structural characterization for polysaccharides from aquatic animals and their major pharmacological activities

The further development of fishery resources is a hotspot in the development of the fishery industry. However, how to develop aquatic animal resources deeply is a key point to be solved in the fishery industry. Over the past decades, numerous aquatic animals have gained great attention in the development and utilization of their bioactive molecules which are of therapeutic applications as nutraceuticals and pharmaceuticals. Recent research revealed that aquatic animals are composed of many vital moieties, such as polysaccharides and proteins, which provide health benefits beyond basic nutrition. In particular, aquatic animal polysaccharides are gaining worldwide popularity owing to their high content, ease of extraction, specific structure, few side effects, prominent therapeutic potential and incorporation in functional foods and dietary supplements. Thus, tremendous research on the isolation, identification and bioactivities of polysaccharides has been carried out. This review presents comprehensive viewpoints on extraction, separation, purification, structural characterization and bioactivity of various polysaccharides from aquatic animals, such as sea cucumber, abalone, oyster and mussels. In addition, this review profiled a brief knowledge on both current challenges and future scope in aquatic animal polysaccharides field. The review will be a direction of deep processing in fishery resources, which is a hotspot, but technical bottleneck. Furthermore, the review could be served as a useful reference material for further investigation, production and application of polysaccharides from aquatic animals in functional foods and therapeutic agents.

Extremely stable high molecular mass soluble multiprotein complex from eggs of sea urchin Strongylocentrotus intermedius with phosphatase activity

It was proposed that most biological processes are performed by different protein complexes. In contrast to individual proteins and enzymes, their complexes usually have other biological functions, and their formation may be important system process for the expansion of diversity and biological functions of different molecules. Identification and characterization of embryonic components including proteins and their multiprotein complexes seem to be very important for an understanding of embryo function. We have isolated and analyzed for the first time a very stable multiprotein complex (SPC; approximately 1100 kDa) from the soluble fraction of extracts of the sea urchin embryos. By fast protein liquid chromatography (FPLC) gel filtration the SPC was well separated from other extract proteins. Stable multiprotein complex is stable in different drastic conditions but dissociates moderately in the presence of 8M urea + 1.0M NaCl. According to sodium dodecyl sulfate polyacrylamide gel electrophoresis data, this complex contains many major, moderate and minor proteins with molecular masses from 10 to 95 kDa. The SPC was destroyed by 8M urea or SDS, and its components were separated using thin layer chromatography, ion-exchange chromatography, gel filtration, and reverse phase chromatography. Using matrix-assisted laser desorption/ionization mass spectrometry of partially dissociated SPC, it was shown that the complex contains not only proteins (10-95 kDa) but also few dozens of peptides with molecular masses from 2 to 9.5 kDa. Short peptides form very strong complexes, which at the treatment of SPC with urea or SDS can be partially break down into smaller complexes having different peptide compositions. Reverse phase chromatography of these complexes after all type of abovementioned chromatographies led to detection from 6 to 11 distinct peaks corresponding to new complexes containing up to a few dozens of peptides. The SPCs possess alkaline phosphatase activity. Progress in the study of embryos protein complexes can help to understand their biological functions.

Bush sophora root polysaccharide could help prevent aflatoxin B1-induced hepatotoxicity in the primary chicken hepatocytes

The aim of this study was to evaluate the effects of bush sophora root polysaccharide (BSRPS) on the aflatoxin B1 (AFB1)-induced hepatotoxicity and to explore the underlying mechanisms. The primary chicken hepatocytes were used as the model in the present experiment. The results showed that AFB1 induced hepatotoxicity of chicken hepatocytes in a dose dependent manner as demonstrated by decreasing cell viability and increasing LDH activity, ALT and AST levels. AFB1 at 0.16 μM significantly increased the levels of hepatic cytochrome P450 1A5 (CYP450 1A5) mRNA and malondialdehyde (MDA) and decreased the activity and mRNA level of manganese superoxide dismutase(SOD2) and the glutathione peroxidases (GSH-Px) activity in the hepatocytes compared with the blank control. BSRPS at 8.93 μM, 17.86 μM, and 35.72 μM supplementation could significantly reverse the above-mentioned changes induced by AFB1, and 17.86 μM of BSRPS has the largest effects on protecting the AFB1-induced hepatocytes damage. Knock-down of SOD2 by SOD2-specific siRNA significantly eliminated the protective effects of BSRPS on AFB1-induced the increase of CYP450 1A5 mRNA levels and hepatotoxicity. These results suggested that the BSRPS has protective effects on AFB1-induced hepatotoxicity by down-regulating CYP450 1A5 mRNA level via up-regulating SOD2 expression in the primary chicken hepatocytes.

Combined SEP and anti-PD-L1 antibody produces a synergistic antitumor effect in B16-F10 melanoma-bearing mice

The increased PD-L1 induces poorer prognosis in melanoma. The treatment with PD-1/PD-L1 antibodies have a low response rate. The combination immunotherapies are the encouraging drug development strategy to receive maximal therapeutic benefit. In this study, we investigated the enhanced antitumor and immunomodulatory activity of combined SEP and αPD-L1 in B16-F10 melanoma-bearing mice. The results shown that combined SEP and αPD-L1 presented significant synergistic antitumor effects, increased the frequency of CD8⁺ and CD4⁺ T cells in spleen and tumor, cytotoxic activity of CTL in spleen, and IL-2 and IFN-γ levels in splenocytes and tumor. The combination treatment also produced synergistic increase in P-ERK1/2 level in spleen. Immunohistochemistry shown that SEP induced the PD-L1 expression in melanoma tissue possibly by promoting IFN-γ excretion, which led to the synergistic anti-tumor effects of aPD-L1 and SEP. Furthermore, in the purified T lymphocyte from the naive mice, the combination of SEP and αPD-L1 had more potent than SEP or αPD-L1 in promoting T lymphocyte proliferation and cytokines secretion including IL-2 and IFN-γ, at least partially by activating MEK/ERK pathway. Our study provides the scientific basis for a clinical trial that would involve combination of anti-PD-L1 mAb and SEP for sustained melanoma control.

In silicoassessment and structural characterization of antioxidant peptides from major yolk protein of sea urchinStrongylocentrotus nudus

Sea urchin gonads have been demonstrated to contain major yolk protein (MYP), which can be hydrolyzed by enzymes to release biologically active peptides.

Enhanced antitumor activity of gemcitabine by polysaccharide-induced NK cell activation and immune cytotoxicity reduction in vitro/vivo

The polysaccharide SEP has been reported to activate NK and T cells via TLR2/4. Here, the combination of gemcitabine (GEM) and SEP against HepG-2 was investigated. SEP apparently enhanced antitumor activity of gemcitabine against liver cancer through stimulating NKG2D and DAP10/Akt pathway to activate NK cells. The NKG2D upregulation could improve the sensitivity of NK-92 cells targeting to its ligand MICA expressed on HepG-2 cells. Meanwhile, GEM up-regulated MICA expression and attenuated soluble MICA secretion through inhibiting ADAM10 expression, which in turn enhanced the cytotoxicity of NK-92 cells against cancer cells. SEP remarkably enhanced GEM antitumor activity with an inhibitory rate of 79.1% in an H22-bearing mouse model. Moreover, SEP reversed atrophy and apoptosis caused by GEM in both spleen and bone marrow through suppressing ROS secretion in vivo. The data indicated that the combination of SEP and GEM is a potential chemo-immunotherapy strategy for liver cancer treatment clinically.

A polysaccharide component from Strongylocentrotus nudus eggs inhibited hepatocellular carcinoma in mice by activating T lymphocytes

A component purified from Strongylocentrotus nudus eggs on a diethylaminoethyl cellulose-52 chromatography column and eluted using a NaCl solution gradient (SEP-S), is a homogeneous polysaccharide of α-D-glucan with a reduced molecular weight of 9.33×10⁵ Da, compared with that of S. nudus egg polysaccharide (SEP). In an in vivo antitumor assay of histocompatibility-22 hepatocellular carcinoma in tumor-bearing mice, the inhibitory rates at SEP-S doses of 5, 10 and 20 mg/kg/day were 38.8, 50.7 and 70.3%, respectively. In addition, the spleen and thymus indices and the percentages of cluster of differentiation (CD) 4⁺ and CD8⁺ T cells were significantly increased, and the activity of cytotoxic T lymphocytes was notably enhanced, suggesting that the anti-hepatocellular carcinoma activity is mediated by boosting the immune system. In vitro experiments also demonstrated that splenocyte proliferation induced by SEP-S was inhibited by the toll-like receptor (TLR) 2 and TLR4 monoclonal antibodies. These data indicate that SEP-S is a polysaccharide component possessing high anti-hepatocellular carcinoma activity and may be a potential immunotherapy candidate for the treatment of liver cancer.

Characterization and immunomodulatory activities of polysaccharides from Spirogyra neglecta (Hassall) Kützing

Sulfated polysaccharides (SP) isolated from freshwater green algae, Spirogyra neglecta (Hassall) Kützing, and fractionated SPs were examined to investigate their molecular characteristics and immunomodulatory activity. The crude and fractionated SPs (F1, F2, and F3) consisted mostly of carbohydrates (68.5-85.3%), uronic acids (3.2-4.9%), and sulfates (2.2-12.2%) with various amounts of proteins (2.6-17.1%). D-galactose (23.5-27.3%), D-glucose (11.5-24.8%), L-fucose (19.0-26.7%), and L-rhamnose (16.4-18.3%) were the major monosaccharide units of these SPs with different levels of L-arabinose (3.0-9.4%), D-xylose (4.6-9.8%), and D-mannose (0.4-2.3%). The SPs contained two sub-fractions with molecular weights (Mw) ranging from 164 × 10(3) to 1460 × 10(3) g/mol. The crude and fractionated SPs strongly stimulated murine macrophages, producing considerable amounts of nitric oxide and various cytokines via up-regulation of their mRNA expression by activation of nuclear factor-kappa B and mitogen-activated protein kinases pathways. The main backbone of the most immunoenhancing SP was (1→3)-L-Fucopyranoside, (1→4,6)-D-Glucopyranoside, and (1→4)-D-Galactopyranoside.

Immunomodulatory effects of polysaccharide from marine fungus Phoma herbarum YS4108 on T cells and dendritic cells

YCP, as a kind of natural polysaccharides from the mycelium of marine filamentous fungus Phoma herbarum YS4108, has great antitumor potential via enhancement of host immune response, but little is known about the molecular mechanisms. In the present study, we mainly focused on the effects and mechanisms of YCP on the specific immunity mediated by dendritic cells (DCs) and T cells. T cell /DC activation-related factors including interferon- (IFN-) γ, interleukin-12 (IL-12), and IL-4 were examined with ELISA. Receptor knock-out mice and fluorescence-activated cell sorting are used to analyze the YCP-binding receptor of T cells and DCs. RT-PCR is utilized to measure MAGE-A3 for analyzing the tumor-specific killing effect. In our study, we demonstrated YCP can provide the second signal for T cell activation, proliferation, and IFN-γ production through binding to toll-like receptor- (TLR-) 2 and TLR-4. YCP could effectively promote IL-12 secretion and expression of markers (CD80, CD86, and MHC II) via TLR-4 on DCs. Antigen-specific immunity against mouse melanoma cells was strengthened through the activation of T cells and the enhancement of capacity of DCs by YCP. The data supported that YCP can exhibit specific immunomodulatory capacity mediated by T cells and DCs.

Immunomodulatory activity in vitro and in vivo of verbascose from mung beans (Phaseolus aureus)

In the present study, the immunostimulatory activity of verbascose from mung beans (Phaseolus aureus) was evaluated by using in vitro cell models and in vivo animal models. The results of in vitro experiments showed that verbascose could enhance the ability of devouring neutral red of peritoneal macrophages and promote the release of nitric oxide and immune reactive molecules such as interleukin (IL)-6, IL-1β, interferon (IFN)-α, and IFN-γ. Treatment with verbascose at a dose of 200 μg/mL exhibited the best effects. For assay in vivo, administration of verbascose at a medium dose of 90 mg/kg body weight could significantly increase the index of spleen, activity of lysozyme in spleen and serum, hemolysin level in serum, and swelling rate of earlap in the delayed type of hypersensitivity (DTH) of immunosuppressed mice. All of the results suggested that verbascose had potent immunostimulatory activity and could be explored as a potential natural immunomodulatory agent in functional foods.

Water soluble sulfated-fucans with immune-enhancing properties from Ecklonia cava

Water-soluble sulfated fucans isolated from Ecklonia cava were fractionated using an anion-exchange chromatography to investigate their molecular characteristics and immunomodulating activities. The crude fucoidan extract and purified fractions (EF1, EF2, and EF3) consisted mostly of different ratios of neutral sugars, proteins, sulfates, uronic acids, and their monosaccharide compositions were also significantly different. The backbone of the most immunoenhancing fraction, EF2, was mainly linked by (1→3)-linked fucopyranosyl and (1→4)-linked mannopyranosyl residues with sulfates at C-4 of fucopyranosyl units. The molecular weights of the crude fucoidan extract and purified fractions ranged from 8.3×10(3) to 442.6×10(3)g/mol. The crude extract, EF1 and EF2 stimulated RAW264.7 cells to produce considerable amounts of nitric oxide and cytokines. The treatment of cells with the sulfated fucans induced the degradation of Iκ-B and the phosphorylation of MAPK in RAW264.7 cells, implying that they might stimulate RAW264.7 cells through the activation of NF-κB and MAPK pathways.

Anticancer and cancer preventive properties of marine polysaccharides: some results and prospects

Many marine-derived polysaccharides and their analogues have been reported as showing anticancer and cancer preventive properties. These compounds demonstrate interesting activities and special modes of action, differing from each other in both structure and toxicity profile. Herein, literature data concerning anticancer and cancer preventive marine polysaccharides are reviewed. The structural diversity, the biological activities, and the molecular mechanisms of their action are discussed.

Immunostimulatory and antiangiogenic activities of low molecular weight hyaluronic acid

The immunostimulatory activities of two low molecular weight hyaluronic acids (LMWHA-1 and LMWHA-2 with MW of 1.45×10(5) and 4.52×10(4) Da, respectively) and HA (MW, 1.05×10(6) Da) were evaluated by using in vitro cell models and in vivo animal models, and their effects on angiogenesis were measured in vivo by using the chick embryo chorioallantoic membrane (CAM) assay. The results demonstrated that LMWHA-1, LMWHA-2 and HA could promote the splenocyte proliferation, increase the activity of acid phosphatase in peritoneal macrophages and strengthen peritoneal macrophages to devour neutral red in vitro in a dose-dependent manner. Furthermore, LMWHA-1 and LMWHA-2 exhibited much stronger immunostimulatory activity than HA. For assay in vivo, LMWHA-1 and LMWHA-2 significantly increased the indices of spleen and thymus, the activity of lysozyme in serum and the swelling rate of earlap in delayed-type hypersensitivity in a dose-dependent manner. In the CAM model, the results showed that LMWHA-1, LMWHA-2 and HA suppressed angiogenesis in chicken embryos. Moreover, LMWHA-1 exhibited higher antiangiogenesis activity than LMWHA-2 and HA. All these results suggested that LMWHA might be a potential natural immunomodulator and a potential candidate compound for antiangiogenic.

Toll-like receptor 2 and Toll-like receptor 4-dependent activation of B cells by a polysaccharide from marine fungus Phoma herbarum YS4108

Various natural polysaccharides are capable of activating the immune system and therefore can be employed as biological response modifiers in anti-tumor therapy. We previously found a homogenous polysaccharide from the mycelium of marine fungus Phoma herbarum YS4108, named YCP, exhibiting strong in vivo antitumor ability via enhancement of the host immune responses. To further elucidate the role of YCP as a biological response modifier, the immunomoduating activities of YCP in B cells was investigated in the current study. We demonstrated that stimulation of YCP with murine splenic B cells resulted in cell proliferation and generation of IgM antibody response. Binding of YCP to B cells was a direct, saturable and reversible event and required TLR2 and TLR4 involvement. TLR2 and TLR4 defunctionalization by either antibody blocking or allele-specific mutation significantly impaired the B-cell proliferative and IgM responses to YCP. YCP interaction with TLR2 and TLR4 led to the activation of intracellular p38, ERK and JNK, as well as the translocation of transcriptional factor NF-κB into nucleus. Furthermore, specific inhibitors of p38, ERK, JNK and NF-κB could attenuate the ability of YCP to induce B cell proliferation and IgM production. Taken together, this study has indicated for the first time the immunostimulating properties of YCP on B cells through a receptor-mediated mechanism, which involves TLR2 and TLR4 and resultant activation of MAPK and NF-κB signaling pathways, thereby highlighting the role of YCP as an efficacious biological response modifier in oncologic immunotherapy.

Molecular properties of water-unextractable proteoglycans from Hypsizygus marmoreus and their in vitro immunomodulatory activities

Four proteoglycans were sequentially extracted from Hypsizygus marmoreus using 0.1 M NaOH (alkali-soluble proteoglycans [F1] and alkali-insoluble proteoglycans [F3]) and 0.1 M HCl (acid-soluble proteoglycans [F2] and acid-insoluble proteoglycans [F4]), and their structures and immunomodulatory activities were investigated. The proteoglycans were found to contain carbohydrates (19.8-82.4%) with various amounts of proteins (7.7-67.3%), and glucose was the major monosaccharide unit present, along with trace amounts of galactose. The molecular weights (Mw) and the radius of gyration (Rg) of these proteoglycans showed ranges of 16 × 10(4)-19,545 × 10(4) g/mol and 35-148 nm, respectively, showing significant variations in their molecular conformations. The backbones of F1 and F2 were mainly connected through a-(1→3), (1→4) and b-(1→6)-glycosidic linkages with some branches. The F1 and F2 proteoglycans significantly stimulated Raw264.7 cells to release nitric oxide (NO), prostaglandin E2 (PGE(2)) and various cytokines, such as IL-1β, TNF-α and IL-6 by inducing their mRNA expressions.

In vitro and in vivo immunomodulatory activity of sulfated polysaccharides from Enteromorpha prolifera

Water-soluble sulfated polysaccharides extracted from Enteromorpha prolifera and fractionated using ion-exchange chromatography (crude, F(1), F(2) and F(3) fractions) were investigated to determine their in vitro and in vivo immunomodulatory activities. The sulfated polysaccharides, especially the F(1) and F(2) fractions, stimulated a macrophage cell line, Raw 264.7, inducing considerable nitric oxide (NO) and various cytokine production via up-regulated mRNA expression. The in vivo experiment results show that the sulfated polysaccharides (the crude and F(2) fractions) significantly increased Con A-induced splenocyte proliferation, revealing their potential comitogenic activity. In addition, IFN-γ and IL-2 secretions were considerably increased by the F(2) fraction without altering the release of IL-4 and IL-5. This implies that the F(2) fraction can activate T cells by up-regulating Th-1 response and that Th-1 cells might be the main target cells of the F(2) fraction. These in vitro and in vivo results suggest that the sulfated polysaccharides are strong immunostimulators.

Isolation, partial characterisation and immunomodulatory activities of polysaccharide from Morchella esculenta

BACKGROUND

Polysaccharides extracted from fungi or algae have shown a variety of medical activities, and the exploitation of polysaccharides for application in pharmacy has been very promising. In this study, the immunomodulatory properties of polysaccharides from Morchella esculenta were investigated to identify immunostimulatory activity and potentially contribute to the therapeutic potential of Morchella esculenta.

RESULTS

A water-soluble polysaccharide, MEP, was obtained from the fermentation broth of Morchella esculenta. Two fractions of this polysaccharide (MEP-I and MEP-II) were extracted and purified. High-performance gel permeation chromatography analysis showed the average molecular weights of two polysaccharides. Structural properties and compositions of these two fractions were examined by Fourier transform infrared and a high-performance liquid chromatography with an evaporative light scattering detector. Active experiments suggested that the MEP had typical immunostimulatory activity.

CONCLUSION

These bioactivity tests showed that the polysaccharides from Morchella esculenta presented significant immune modulating activity, and this finding may offer the basis for the popular use of polysaccharides in functional foods or medicine.

A Water-Soluble Polysaccharide from the Fruit Bodies of Bulgaria inquinans (Fries) and Its Anti-Malarial Activity

A water-soluble polysaccharide (BIWS-4b) was purified from the fruit bodies of Bulgaria inquinans (Fries). It is composed of mannose (27.2%), glucose (15.5%) and galactose (57.3%). Its molecular weight was estimated to be 7.4 kDa (polydispersity index, Mw/Mn: 1.35). Structural analyses indicated that BIWS-4b mainly contains (1 → 6)-linked, (1 → 5)-linked and (1 → 5,6)-linked β-Galf units; (1 → 4)-linked and non-reducing terminal β-Glcp units; and (1 → 2)-linked, (1 → 6)-linked, (1 → 2,6)-linked and non-reducing terminal α-Manp units. When examined by the 4-day method and in a prophylactic assay in mice, BIWS-4b exhibited markedly suppressive activity against malaria while enhancing the activity of artesunate. Immunological tests indicated that BIWS-4b significantly enhanced macrophage phagocytosis and splenic lymphocyte proliferation in malaria-bearing mice and normal mice. The anti-malarial activity of BIWS-4b might be intermediated by enhancing immune competence and restoring artesunate-suppressed immune function. Thus, BIWS-4b is a potential adjuvant of anti-malaria drugs.