Lentinan Research Articles

Effect of Lentinan on Peyer's patch structure and function in an immunosuppressed mouse model

Lentinan (LNT), a polysaccharide isolated from Lentinus edodes, has been shown to stimulate immune response. Despite its widespread use owing to its health benefits, epidemiologic and experimental studies that address the biological activities of LNT after oral administration to animals or humans are rare. In this study, the effects of LNT on the intestinal mucosal immune system of immunosuppressed mice were investigated. The number and size of the Peyer's patches (PPs), proliferation ability of PP lymphocytes, T and B lymphocyte percentage, and T-cell activation proportion, as well as the number of M-like cells in PPs, were determined. The antigen transfer ability of M-like cells and intestinal secretory immunoglobulin A (IgA) levels were also detected. After oral administration of LNT for 7 days, the number of PPs, lymphocytes in PPs, and the level of intestinal soluble IgA in immunosuppressed mice were increased. LNT maintained the percentage of T and B lymphocytes and upregulated the proportion of activated T cells in PPs. Furthermore, the number of M-like cells, which were differentiated from intestinal epithelial cells, and their antigen transfer ability were enhanced. These results indicate that orally administered LNT can improve the immune status of the intestinal mucosa in immunosuppressed mice.

Lentinan modulates intestinal microbiota and enhances barrier integrity in a piglet model challenged with lipopolysaccharide.

The intestinal microbiota plays a vital role in metabolism, pathogen resistance, and immune development in host cells, and is modifiable by dietary change. Lentinan (LNT), a type of mushroom polysaccharide, is known to ameliorate intestinal inflammation with the potential of therapeutic effect on digestive diseases. We hypothesized that LNT could alleviate Escherichia coli lipopolysaccharide (LPS)-induced intestinal injury via regulating the composition and metabolites of intestinal microbiota in a piglet model. Twenty-four weaned piglets were used in a 2 × 2 factorial design, and the main factors included a dietary treatment (basal or LNT diet) and immunological challenge (LPS or saline). After feeding basal or LNT diet for 21 days, pigs were injected with LPS or saline. At 4 h post-injection, pigs were killed and jejunum, ileum and cecal digesta were collected. LNT improved intestinal morphology and barrier function. LNT also inhibited inflammatory signaling pathways (toll-like receptor 4 and nucleotide binding oligomerization domain protein) and pro-inflammatory cytokines (tumor necrosis factor-α, interleukin-1β and interleukin-6) expression, as well as up-regulated the heat shock protein 70 expression in small intestine. In addition, LNT enhanced the concentrations of propionate, butyrate, isobutyrate and isovalerate in cecal digesta, resulting in a significant increase in histone acetylation without affecting the protein level of G protein-coupled receptor 41 (GPR41), a short chain fatty acid receptor. Bacterial 16S rRNA gene pyrosequencing showed that LNT had a great impact on gut microbiota composition at different taxonomic levels. Moreover, the correlation analysis revealed some potential relationships between cecal metabolites and certain intestinal microbiota. These results indicate that LNT promotes intestinal health, in part, through altering intestinal microbiota composition and increasing the short chain fatty acid synthesis, which subsequently lead to a reduction in inflammation and hyper-acetylation of histones.

Green synthesis of palladium nanoparticles using lentinan for catalytic activity and biological applications.

The green synthesis of palladium nanoparticles (Pd NPs) for catalysis and biological applications has been gaining great interest. To replace complex plant extracts, lentinan (LNT) may be a good reducing and stabilizing agent. In this work, a simple and green method using LNT to reduce and stabilize palladium Pd NPs was verified. The resulting LNT stabilized palladium nanoparticles (Pdn-LNT NPs) were characterized by UV-Vis spectroscopy, DLS, TEM, and XPS. The results indicated that Pd NPs inside of Pdn-LNT NPs had a small size (2.35–3.32 nm). Pdn-LNT NPs were stable in solution for 7 days. In addition, Pdn-LNT NPs had higher catalytic activity towards the reduction of 4-nitrophenol than other catalysts. More importantly, Pdn-LNT NPs had negligible cytotoxicity towards cells and showed good antioxidant activity. Taken together, the prepared Pdn-LNT NPs have great potential bio-related applications.

The Effects of Lentinan on the Expression Patterns of β-Catenin, Bcl-2, and Bax in Murine Bone Marrow Cells Are Associated with Enhancing Dectin-1.

This study was focused on investigating the effect of lentinan (LNT) on the expression patterns of β-catenin, Bcl-2, and Bax in murine bone marrow cells (BMCs). Adult BALB/L mice were divided into four groups (n = 10 for each group) that consisted of normal control adult BALB/L mice (control group) and adult BALB/L mice with intraperitoneal injection of low, medium, and high doses of LNT (LLen, MLen, and HLen, respectively). Cells of bone marrow from adult BALB/L mice were cultured in DMEM medium with or without laminarin (inhibitor of dectin-1) to investigate the role of dectin-1 in the effect of lentinan on the expression profile of β-catenin, Bcl-2, and Bax using western blotting and RT-PCR methods. The ELISA results indicated that the expression profiles of dectin-1 were significantly elevated in BMCs from groups of LLen, MLen, and HLen compared with the control group (P < 0.05). The protein and gene expression profiles of β-catenin and Bax increased significantly in murine BMCs from groups of MLen and HLen compared with the control group or the LLen group (P < 0.05). In contrast, the protein and gene expression levels of Bcl-2 decreased significantly in BMCs from the LLen, MLen, and HLen groups compared with the control group (P < 0.05). Furthermore, the expression profiles of β-catenin, Bcl-2, and Bax reversed with the administration of laminarin (P < 0.05). Taken together, our results identified that the changing expression profiles of β-catenin, Bcl-2, and Bax in murine BMCs are associated with enhancing dectin-1.

Enhanced response of tamoxifen toward the cancer cells using a combination of chemotherapy and photothermal ablation induced by lentinan-functionalized multi-walled carbon nanotubes

A lentinan (LEN) functionalized multi-walled carbon nanotubes (MWCNTs) drug delivery system, using tamoxifen (TAM) as a model anticancer agent, was developed by a simple non-covalent approach. This developed system (MWCNTs-TAM-LEN) possessed good stability, water dispersibility and extraordinary photothermal properties. It was demonstrated by the in vitro experiments that MWCNTs-TAM-LEN had enhanced cellular uptake, antitumor activity and cell apoptosis on Mcf-7 cells in comparison with TAM and MWCNTs-TAM. The cell inhibition rate and apoptosis rate of Mcf-7 cells treated by MWCNTs-TAM-LEN with near-infrared (NIR) were 67.1% and 66.5% higher than that of equivalent concentration of TAM with NIR irradiation treatment, respectively. The enhanced antitumor efficacy of MWCNTs-TAM-LEN was realized via the synergistic function of chemotherapy and photothermal ablation under NIR laser irradiation.

Structural characterization and antiviral activity of lentinan from Lentinus edodes mycelia against infectious hematopoietic necrosis virus

A novel lentinan (LNT-I) was extracted from Lentinus edodes mycelia, and purified by an anion-exchange DEAE cellulose column and Sephadex G-200 gel. The structural characterization of LNT-I was determined by gas chromatography-mass spectrometry, high performance gel permeation chromatography, Fourier transform infrared spectrometry and 1D-nuclear magnetic resonance spectroscopy. The results showed that LNT-I was a β-(1 → 3)-glucan backbone with -(1 → 6)-glucosyl side-branching units terminated by mannosyl and galactosyl residues, and its molecular weight was 3.79 × 105 Da. LNT-I consisted of glucose, mannose and galactose with the molar ratio of 19.26:1.20:1.00. LNT-I represented the prominent antiviral activity to IHNV at MOI of 0.05 and 0.10, respectively. Direct inactivation and the antiviral ability in pre-addition, co-addition and post-addition to IHNV (MOI of 0.05) were 62.34%, 39.60%, 53.63% and 82.38%, respectively under 100 μg/mL of LNT-I. Antiviral mechanisms of LNT-I mainly involved in the direct inactivation and the inhibition of viral replication. Moreover, LNT-I significantly down-regulated the expression level of TNF-α, IL-2 and IL-11, and up-modulated the expression levels of IFN-1 and IFN-γ after challenging with IHNV. The results indicated that the inhibitory effects of LNT-I on IHNV infection were possibly attributed to its regulation of the innate immune responses and specific immunity.

Effects of lentinan on the function of phagocyte in long-term heavy-duty exercising mice

Excessive exercise can lead to decreased immune function of phagocytes. This study used 50 male Kunming mice aged 40 days to evaluate the effects of lentinan (LNT) on the number of functional blood cells, the phagocytosis, peripheral blood neutrophils, and peritoneal macrophages of long-term heavy-duty exercising mice. The mice were subjected to 45 min of 5% load weight swimming training for 4 weeks, 6 times per week. Different doses of LNT were administered in the HL + T group (400 mg/kg/day), ML + T group (200 mg/kg/day), LL + T group (100 mg/kg/day), and S + T group (saline only) during the 4 weeks of excessive exercise. The phagocytic function of mice in each group was measured after long-term heavy-load exercise. The results showed that the number of white blood cells decreased significantly; the number of neutrophils and the phagocytic index of blood neutrophils in mice were significantly decreased at the end of the exercise. The macrophage phagocytosis index also decreased significantly on the fourth day after the end of the exercise. The difference was significant, and the difference in the phagocytosis rate was not obvious. The numbers of white blood cells in ML + T and HL + T groups were significantly higher than that in S + T and LL + T groups. The number of neutrophils in the ML + T and HL + T groups was significantly higher than that in the S + T and LL + T groups. The phagocytic rate and phagocytic index of neutrophils in the HL + T group were also significantly higher than those in the S + T group. The macrophage phagocytosis rate of ML + T and LL + T mice was significantly higher than that of S + T, and the phagocytic index difference was not significant. Four weeks of heavy-load exercise resulted in a decrease in phagocytic immune function in mice. Excessive exercise while feeding on LNT can improve the immune function of mice phagocytic cells. There was a positive correlation between the effect of LNT on the function of phagocytes and the LNT dose.

Use of Lentinan To Control Sharp Eyespot of Wheat, and the Mechanism Involved.

Lentinan (LNT), a complex polysaccharide with a β-(1→3)-linked backbone of d-glucose residues, has been reported to inhibit plant diseases. Our objective was to explore the efficacy and action mechanism of LNT used as a seed dressing to control sharp eyespot of wheat. Seed dressing promoted wheat growth. At control germination rates of 50%, 8 g of LNT/100 kg of seeds of the Jimai 22, Shannong 23, and Luyuan 502 cultivars significantly increased seed germination to 54%, 52%, and 51%, respectively. Seven days after emergence, the heights and root activity of wheat treated with LNT were significantly greater than those of controls. These effects were dose-dependent. At this time, the plant heights of Jimai 22, Shannong 23, and Luyuan 502 cultivars were 9.52, 8.52, and 10.52 cm, respectively, significantly higher than that of the controls. LNT prevented the development of wheat sharp eyespot. In the highly susceptible Jimai 22 cultivar, sharp eyespot development was reduced by 33.7%, 31.9%, and 30.4% at 7, 14, and 21 days after germination. LNT somewhat increased phenylalanine ammonia-lyase, peroxidase, and superoxide dismutase activity; reduced the malondialdehyde content; increased chlorophyll a and b levels; and enhanced the root vigor of wheat. These effects peaked 7 days after germination. LNT increased transcription of the genes encoding alternative oxidase (AOX) and β-1,3-glucanase (GLU), the salicylic acid signaling pathway-related gene NbPR1a, and the sharp eyespot resistance-related gene RS33. A significant dose-effect relationship was evident in terms of AOX transcription; we thus speculate that AOX may be the target gene.

Oridonin increases anticancer effects of lentinan in HepG2 human hepatoblastoma cells.

The aim of the present study was to investigate whether oridonin is able to increase the effects of lentinan (LNT) in HepG2 human hepatoblastoma cells by MTT, flow cytometry, reverse transcription-quantitative polymerase chain reaction and western blot analysis. The in vitro results demonstrated that 20 µg/ml of oridonin was a nontoxic concentration for L02 normal liver cells and HepG2 liver cancer cells. Furthermore, treatment with 0-200 µg/ml LNT was only able to decrease the viability of HepG2 liver cancer cells. The growth inhibitory rate of the LNT-L (100 µg/ml) treatment group was 20.7% and the rate of the LNT-H (200 µg/ml) treatment group was 54.8%. Notably, the growth inhibitory rate of the oridonin + LNT-H group was 84.3%. The highest percentage of apoptotic cells was observed in the oridonin + LNT-H group (20 µg/ml oridonin and 200 µg/ml LNT). The percentage of apoptotic cells in the oridonin + LNT-H group was significantly different from the percentage of apoptotic cells in the LNT-H (26.1%) and the LNT-L (16.8%) groups. Treatment with LNT produced an increase in caspase-3, caspase-9, Bcl-2-like protein 4, p53, p21, nuclear factor κB inhibitor-α mRNA and protein expression and a decrease in B-cell lymphoma 2 and nuclear factor-κB expression in HepG2 cells compared with untreated control cells. Treatment with a combination of oridonin and LNT-H induced a further increase in expression with the biggest differences in expression observed between the oridonin + LNT-H group and control. It was observed that treatment with oridonin was able to increase the anticancer effects of LNT in HepG2 cells. Therefore, oridonin may be used to sensitize cells to LNT.

Oridonin enhances in vitro anticancer effects of lentinan in SMMC-7721 human hepatoma cells through apoptotic genes.

The aim of the present study was to determine the ability of oridonin to enhance the anticancer activity of lentinan (LNT) in SMMC-7721 human hepatoma cells in vitro by using various techniques, including MTT, flow cytometry, quantitative PCR and western blot assays. The results demonstrated that 20 µg/ml was a non-toxic concentration of oridonin for L02 normal liver cells and SMMC-7721 cells, while 0-200 µg/ml of LNT only had anti-proliferative effects on SMMC-7721 cells. LNT at 100 and 200 µg/ml inhibited the growth of SMMC-7721 cells by 22.8 and 60.0%, respectively, and after addition of 20 µg/ml oridonin, the inhibitory rate of 100 and 200 µg/ml LNT was increased to 47.2 and 80.7%, respectively. Oridonin (20 µg/ml) + LNT (200 µg/ml)-treated SMMC-7721 cells showed the highest apoptotic rate, which was 40.5±2.5%, which was higher than that of cells treated with LNT only. LNT raised the mRNA and protein expression of caspase-3, -8 and -9 as well as B-cell lymphoma 2 (Bcl-2)-associated X protein, p53 and p21, while reducing the expression of Bcl-2, Bcl extra large protein, epidermal growth factor (EGF) and EGF receptor expression in SMMC-7721 cells as compared to that in control cells. Treatment with 20 µg/ml oridonin and 200 µg/ml LNT increased these changes of gene expression. From the obtained results, it may be concluded that oridonin raised the in vitro anti-cancer effects of LNT in SMMC-7721 cells. Oridonin may also be used as a sensitizing agent to increase the anticancer activity of LNT in vivo.

Lentinan produces a robust antidepressant-like effect via enhancing the prefrontal Dectin-1/AMPA receptor signaling pathway

Lentinan (LNT) is an immune regulator and its potential and mechanism for the treatment of mood disorder is of our interest. Dectin-1 is a β-glucan (including LNT) receptor that regulates immune functions in many immune cell types. Cumulative evidence has suggested that the glutamatergic system seems to play an important role in the treatment of depression. Here, we studied the antidepressant-like effects of LNT and its therapeutical target in regulating the functions of AMPA receptors. We found that 60min treatment with LNT leads to a significant antidepressant-like effect in the tail suspension test (TST) and the forced swim test (FST) in mice. The antidepressant-like effects of LNT in TST and FST remained after 1day or 5days of injections. Additionally, LNT did not show a hyperactive effect in the open field test. Dectin-1 receptor levels were increased after LNT treatment for 5days and the specific Dectin-1 inhibitor laminarin was able to block the antidepressant-like effects of LNT. After 5days of treatment, LNT enhanced p-GluR1 (S845) in the prefrontal cortex (PFC); however, the total GluR1, GluR2, and GluR3 expression levels remained unchanged. We also found that the AMPA-specific blocker GYKI 52466 was able to block the antidepressant-like effects of LNT. This study identified LNT as a novel antidepressant with clinical potential and a new antidepressant mechanism for regulating prefrontal Dectin-1/AMPA receptor signaling.

Lentinan protects pancreatic β cells from STZ-induced damage.

Pancreatic β‐cell death or dysfunction mediated by oxidative stress underlies the development and progression of diabetes mellitus (DM). In this study, we evaluated the effect of lentinan (LNT), an active ingredient purified from the bodies of Lentinus edodes, on pancreatic β‐cell apoptosis and dysfunction caused by streptozotocin (STZ) and the possible mechanisms implicated. The rat insulinoma cell line INS‐1 were pre‐treated with the indicated concentration of LNT for 30 min. and then incubated for 24 hrs with or without 0.5 mM STZ. We found that STZ treatment causes apoptosis of INS‐1 cells by enhancement of intracellular reactive oxygen species (ROS) accumulation, inducible nitric oxide synthase (iNOS) expression and nitric oxide release and activation of the c‐jun N‐terminal kinase (JNK) and p38 mitogen‐activated protein kinase (MAPK) signalling pathways. However, LNT significantly increased cell viability and effectively attenuated STZ‐induced ROS production, iNOS expression and nitric oxide release and the activation of JNK and p38 MAPK in a dose‐dependent manner in vitro. Moreover, LNT dose‐dependently prevented STZ‐induced inhibition of insulin synthesis by blocking the activation of nuclear factor kappa beta and increasing the level of Pdx‐1 in INS‐1 cells. Together these findings suggest that LNT could protect against pancreatic β‐cell apoptosis and dysfunction caused by STZ and therefore may be a potential pharmacological agent for preventing pancreatic β‐cell damage caused by oxidative stress associated with diabetes.

Lentinan mitigates therarubicin-induced myelosuppression by activating bone marrow-derived macrophages in an MAPK/NF-κB-dependent manner.

Bone marrow (BM) suppression (also known as myelosuppression) is the most common and most severe side-effect of therarubicin (THP) and thereby limits the clinical application of this anticancer agent. Lentinan (LNT), a glucan extracted from dried shiitake mushrooms (Lentinulaedodes), exhibits a variety of pharmacological activities. The objectives of the present study were to determine the effect of LNT on the myelosuppression of THP-treated mice and to examine the pharmacological mechanism of these effects. Invivo experiments indicated that non-cytotoxic levels of LNT strongly increased blood myeloperoxidase (MPO) activity; improved BM structural injuries; increased the numbers of leukocytes and neutrophils in the blood and BM; elevated the blood levels of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF); and reduced the self-healing period in THP-treated mice. Invitro experiments indicated that LNT increased the viability of BM-derived macrophages (BMDMs) in a time-and dose-dependent manner without toxic side-effects and markedly increased the release of G-CSF, GM-CSF and M-CSF by BMDMs. Further analyses revealed that LNT activated the NF-κB and MAPK signalling pathways and promoted the nuclear import of p65 and that BAY11-7082 (a specific inhibitor of NF-κB) suppressed the release of G-CSF, GM-CSF and M-CSF. Furthermore, we found that U0126, SB203580 and SP600125 (specific inhibitors of ERK, p38 and JNK, respectively) markedly inhibited the IKK/IκB/NF-κB-dependent release of G-CSF, GM-CSF and M-CSF. In conclusion, LNT induces the production of G-CSF, GM-CSF and M-CSF by activating the MAPK/NF-κB signalling pathway in BM cells, thereby mitigating THP-induced myelosuppression.

Activation of the NRF2-ARE signalling pathway by the Lentinula edodes polysaccharose LNT alleviates ROS-mediated cisplatin nephrotoxicity

The nephrotoxicity of cisplatin (cis-DDP) limits its general clinical applications. Lentinan (LNT), a dextran extracted from the mushroom Lentinula edodes, has been shown to have multiple pharmacological activities. The primary objective of the current study was to determine whether and how LNT alleviates cis-DDP- induced cytotoxicity in HK-2 cells and nephrotoxicity in mice. LNT did not interfere with cisplatin's anti-tumour efficacy in vitro and functioned cooperatively with cis-DDP to inhibit activity in HeLa and A549 tumour cells. LNT alleviated the cis-DDP-induced decrease in HK-2 cell viability, caspase-3 activation and cleavage of the DNA repair enzyme PARP, decreased HK-2 cell apoptosis and inhibited reactive oxygen species (ROS) accumulation in HK-2 cells. The inhibitor of ROS (N-acetyl-L-cysteine, NAC) could decreased the apoptosis of HK-2 cell. In addition, LNT significantly prevented cis-DDP-induced kidney injury in vivo. LNT itself could not eliminate ROS levels in vitro. Further studies demonstrated that LNT induced NF-E2 p45-related factor 2 (Nrf2) protein and mRNA expression in a time- and dose-dependent manner. LNT promoted Nrf2 translocation to the nucleus and binding to the antioxidant-response element (ARE) sequence and induced the transcription and translation of heme oxygenase 1 (HO-1), aldo-keto reductases 1C1 and 1C2 (AKR1C), and NADP(H):quinone oxidoreductase 1 (NQO1). Finally, we used hNrf2 siRNA and an Nrf2 agonist (tBHQ) to inhibit or enhance Nrf2 expression. The results demonstrated that the LNT-mediated alleviation of cis-DDP-induced nephrotoxicity was achieved by preventing the accumulation of ROS in a manner that depended on the activation of the Nrf2-ARE signalling pathway.

Folate‐decorated Polysaccharide‐doxorubicin Polymer: Synthesis, Characterization, and Activity in HeLa Cells

In order to develop the application of the natural polysaccharide lentinan (LNT) and decrease the side effects of doxorubicin, we successfully synthesized a novel folate‐modified maleilated lentinan‐doxorubicin (FA‐M.LNT‐DOX) polymer and used it for tumor‐targeted drug delivery. The release efficiency and cytotoxicity of the prodrugs were evaluated in vitro. Although DOX release from FA‐M.LNT‐DOX was quite slow in a neutral buffer, it was particularly fast in an acidic solution with a pH of 5.0. Compared with DOX, FA‐M.LNT‐DOX showed higher cytotoxicity in HeLa cells and significantly lower cytotoxicity in normal cells. These results suggested that FA‐M.LNT‐DOX could be considered as a potential drug delivery candidate for folate receptor‐positive cancer therapy.

Removal of triphenylmethane dyes by calcium carbonate–lentinan hierarchical mesoporous hybrid materials

An inorganic–organic hybrid material with hierarchical mesoporous structure was prepared by involving lentinan (LTN) into CaCO3 crystal using a simple method at mild condition. The characterization of CaCO3–LTN hybrid materials indicated that it has higher surface area, more adsorption sites and better dispersion in water compared to bare CaCO3 crystal due to rich organic ligands of LTN and hierarchical structure.CaCO3–LTN hybrid materials was applied to the removal of triphenylmethyl dyes (TPMs) including crystal violet (CV), malachite green (MG) and aniline blue (AB). A powerful adsorption capability of the hybrid materials to dyes was observed, and moreover, it was found that a very rapid and efficient oxidative degradation of dyes by H2O2 can be achieved in the assist of CaCO3–LTN hybrid materials due to the reactants concentrated into its plentiful and negative charged pores. CV, MG, and AB can be complete decolorized by H2O2+CaCO3–LTN after 30min, 10min, and 2min, respectively. Moreover, cation dyes, besides TPMs, were also suitable to be treated by this H2O2+CaCO3–LTN system. These results ensure the CaCO3–LTN hybrid material a promising candidate for treatment of effluent of textile industry.

Self-enhanced electrochemiluminescence immunosensor based on nanowires obtained by a green approach

Co-reactant electrochemiluminescence (ECL) is a simple and effective method for sensitive detection with amplified ECL signals. However, the intermolecular interaction between the luminescent reagents and their corresponding co-reactants, which is widely applied, has disadvantages in poor stability, low efficiency of electron transfer and relatively high loss of energy. In this work, an intramolecular self-enhanced ECL is proposed to settle this problem. Firstly, palladium nanowires (PdNWs) are synthesized with a green procedure in which Lentinan (LNT), one of β-glucans with a triple helical conformation (t-LNT) in aqueous solution and single chains (s-LNT) at a temperature higher than 130°C, is used as stabilizer and reducing agent. The abtined PdNWs are applied to immobilize polyamidoamine (PAMAM) dendrimer which further reacts with tris (4, 4′-dicarboxylicacid-2, 2′-bipyridyl) ruthenium (II) dichloride to form a new electrochemiluminescent derivative (PdNWs–PAMAM–Ru). In this way, the Ru (II) luminophore and its co-reactive groups (amine groups in PAMAM) exist in the same complex, by which the electronic transmission distance is shortened and the luminous properties including stability and efficiency are enhanced. Moreover, due to the high specific surface areas and good electro-catalytic ability of PdNWs, the obtained PdNWs–PAMAM–Ru can be also applied to immobilize detection antibody (Ab2). Then, a sandwiched and sensitive ECL immunosensor is fabricated for the detection of carcinoembryonic antigen (CEA) with a wide linear ranged from 0.001ngmL−1 to 80ngmL−1 and a low detection limit of 0.3pgmL−1.

Alkali-soluble polysaccharide, isolated from Lentinus edodes, induces apoptosis and G2/M cell cycle arrest in H22 cells through microtubule depolymerization.

The aim of the study was to evaluate the pro-apoptotic effects of polysaccharides derived from Lentinus edodes and further elucidated the mechanisms of this action. Our results demonstrated that marked morphological changes of apoptosis were observed after treatment of L. edodes polysaccharides [Lentinan (LTN)]. Moreover, LTN-induced cell apoptosis was characterized by a rapid stimulation of reactive oxygen species production, the loss of mitochondrial membrane potential and an increase in intracellular concentration of Ca(2+) . In addition, the results of the haematoxylin and eosin and TUNEL assay further confirmed that LTN-induced apoptosis in vivo. Furthermore, flow cytometry analysis showed that LTN could arrest the cell cycle at G2/M phase, and immunofluorescence showed LTN caused disruption of microtubule. These results suggest that disruption of cellular microtubule network, arrest of the cell cycle at G2/M phase and induction of apoptosis may be one of the possible mechanisms of anti-tumour effect of LTN.

Protective effect of polysaccharides on simulated microgravity-induced functional inhibition of human NK cells

Polysaccharides are believed to be strong immunostimulants that can promote the proliferation and activity of T cells, B cells, macrophages and natural killer (NK) cells. This study aimed to investigate the effects of five polysaccharides (Grifola frondosa polysaccharide (GFP), lentinan (LNT), G. lucidum polysaccharide (GLP), Lycium barbarum polysaccharide (LBP) and yeast glucan (YG)) on primary human NK cells under normal or simulated microgravity (SMG) conditions. Our results demonstrated that polysaccharides markedly promoted the cytotoxicity of NK cells by enhancing IFN-γ and perforin secretion and increasing the expression of the activating receptor NKp30 under normal conditions. Meanwhile polysaccharides can enhance NK cell function under SMG conditions by restoring the expression of the activating receptor NKG2D and reducing the early apoptosis and late apoptosis/necrosis. Moreover, the antibody neutralization test showed that CR3 may be the critical receptor involved in polysaccharides induced NK cells activation. These findings indicated that polysaccharides may be used as immune regulators to promote the health of the public and astronauts during space missions.

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

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