The effect of lentinan on dexamethasone-induced immunosuppression in mice

The immune system acts as a vital defense barrier against pathogenic invasions, and its stable operation is crucial for maintaining body health. Nevertheless, various natural or artificial factors can compromise the body's immune function, leading to immunosuppression, which may interfere with the efficacy of vaccination and increase the susceptibility of the body to disease-causing pathogens. In an effort to ensure successful vaccinations and improve overall physical well-being, the search for appropriate immune regulators to enhance immunity is of paramount importance. Lentinan (LNT) has a significant role in immune regulation and vaccine adjuvants. In the present study, we constructed an immunosuppressive model using dexamethasone (DEX) and demonstrated that LNT could significantly improved antibody levels in immunosuppressive mice and stimulated T-lymphocyte proliferation and differentiation in intestinal Peyer's patches. LNT also increased the production of secretory immunoglobulin A (sIgA) in the duodenal fluid, the number of goblet cells, and the proportion of mucin area. Moreover, LNT modulated the intestinal microbiota and increased the production of short-chain fatty acids. Additionally, LNT promoted the proliferation, differentiation, and pro-inflammatory cytokines production of DEX-treated splenic T lymphocytes in vitro. Thus, the present study highlights the potential of LNT in reversing immunosuppression and avoiding the failure of vaccination.

Lentinan-loaded GelMA hydrogel accelerates diabetic wound healing through enhanced angiogenesis and immune microenvironment modulation

Diabetic wound healing is a substantial clinical challenge, characterized by delayed angiogenesis and unresolved inflammation. Lentinan, a polysaccharide extracted from shiitake mushrooms, has the potential to regulate both macrophage polarization and angiogenesis, though this aspect remains inadequately explored. To facilitate lentinan's clinical utility, we have developed a GelMA hydrogel encapsulated with lentinan (10 μM), offering a controlled release mechanism for sustained lentinan delivery at the wound site. Application of the lentinan-encapsulated delivery system topically significantly expedites wound closure compared to control groups. Furthermore, histological examination demonstrates enhanced neovascularization and reduced inflammation in lentinan-treated wounds, as evidenced by increased M2 macrophage infiltration. Moreover, our results indicated that lentinan-induced AMPK activation promotes DAF16 expression, enhancing the resistance of macrophages and HUVECs to oxidative stress in high-glucose environments, thereby promoting M2 macrophage polarization and angiogenesis. All these findings underscore lentinan's capacity to modulate macrophage polarization and angiogenesis via the AMPK/DAF16 pathway, ultimately facilitating the healing of diabetic wounds.

Lentinan progress in inflammatory diseases and tumor diseases

Shiitake mushrooms are a fungal food that has been recorded in Chinese medicine to nourish the blood and qi. Lentinan (lLNT) is an active substance extracted from shiitake mushrooms with powerful antioxidant, anti-inflammatory, anti-tumor functions. Inflammatory diseases and cancers are the leading causes of death worldwide, posing a serious threat to human life and health and posing enormous challenges to global health systems. There is still a lack of effective treatments for inflammatory diseases and cancer. LNT has been approved as an adjunct to chemotherapy in China and Japan. Studies have shown that LNT plays an important role in the treatment of inflammatory diseases as well as oncological diseases. Moreover, clinical experiments have confirmed that LNT combined with chemotherapy drugs has a significant effect in improving the prognosis of patients, enhancing their immune function and reducing the side effects of chemotherapy in lung cancer, colorectal cancer and gastric cancer. However, the relevant mechanism of action of the LNT signaling pathway in inflammatory diseases and cancer. Therefore, this article reviews the mechanism and clinical research of LNT in inflammatory diseases and tumor diseases in recent years.

Systematic review and meta-analysis on the efficacy and safety of Injectable Lentinan combined with chemotherapy in the treatment of gastric cancer

BACKGROUND

This study employed a meta-analysis to evaluate the efficacy and safety of adjunctive treatment with injectable Lentinan (LNT) in combination with chemotherapy for gastric cancer (GC).

METHODS

Computer-based searches of 6 databases were performed to identify randomized controlled trials (RCTs) relevant to the treatment of GC with LNT through mid-March 2023. Two independent researchers performed risk of bias assessment and trial sequential analysis(TSA), extracted the data and used Revman 5.3 software for data analysis. The certainty of evidence was graded based on the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach.

RESULTS

A total of 31 RCTs with 2729 patients were included in the analysis. The results revealed that adjunctive therapy with LNT was associated with improved treatment efficacy (RR = 1.48, 95%CI: 1.36 ∼ 1.61, p < 0.00001), improvement in clusters of differentiation (CD3+, CD4+, and CD4+/CD8+), natural killer (NK) cells, and quality of life assessment (RR = 1.32, 95%CI: 1.20 ∼ 1.45, p < 0.00001) compared to using chemotherapy alone. In addition, there was a reduction in CD8+ levels, incidence of white blood cell decline, gastrointestinal reactions, and platelet decline. TSA results indicated that there was sufficient evidence to draw firm conclusions about these outcomes, and the GRADE scores showed 'high' or 'moderate' quality of evidence for these outcomes.

CONCLUSION

The efficacy of treatment of GC with LNT in combination with chemotherapy was found to be better than chemotherapy alone. And no serious adverse effects were observed. However, further RCTs are needed to further validate the results of this study.

Single-injection subunit vaccine for rabies prevention using lentinan as adjuvant

Current rabies vaccines require 5 doses to provide full protection from the deadly virus, which significantly reduce the compliance of recipients. To minimize the number of immunizations herein single injection vaccines were developed. First a single injection vaccine was designed using rabies virus glycoprotein (G protein) as antigen. A time-controlled release system which uses dynamic layer-by-layer films as erodible coating was employed to accomplish multiply pulsatile releases of G protein. The single-injection vaccine elicits potent humoral and cellular immune responses comparable to the corresponding multi-dose ordinary vaccines because of their similar release pattern of G protein. To further improve its performance, a second single injection vaccine, in which lentinan was added as adjuvant, was designed. This single-injection vaccine again elicits humoral and cellular immune responses comparable to the corresponding multi-dose ordinary vaccines because of their similar release pattern of antigen and adjuvant. In addition, the second single-injection vaccine elicits higher level immune response and provides higher efficiency on virus inhibition than the first one because lentinan can booster immune response.

Lentinan-functionalized graphene oxide hydrogel as a sustained antigen delivery system for vaccines

Hydrogel has been proven to have the ability to deliver antigens continuously to achieve slow vaccine delivery, which makes it a promising candidate for an adjuvant delivery platform. Meanwhile, graphene oxide (GO) has garnered significant attention due to its good biosafety, excellent surface area and easy modification. However, GO exists as weak colloidal particles and poses challenges in self-assembling into a hydrogel structure. Here, we propose an innovative strategy involving self-assembling lentinan-functionalized graphene oxide hydrogel ((LNT-GO Gel) by simply mixing lentinan (LNT)-functionalized GO with polyethylene imide (PEI), which can simultaneously encapsulate antigens, achieve long-lasting release of antigens and generate excellent adjuvant activity. The results indicated that the LNT-GO Gel can control the release of OVA at the injection site and confer targeted delivering capacity to lymph nodes. And the date demonstrates that LNT-GO Gel displays favorable safety and biodegradability in vivo. Moreover, LNT-GO Gel can enhance the activation and maturation of dendritic cells (DCs) in lymph node, induce stronger OVA-specific antibody response, and promote spleen T lymphocyte differentiation, which underscores that LNT-GO Gel has ability to generate stronger antigen-specific humoral and cellular immune responses. Collectively, these results demonstrate the adjuvant potential of the lentinan-functionalized graphene oxide hydrogel (LNT-GO Gel) for subunit vaccine.

Atomic force microscopy based conformation and immunological activity of Lentinan injections

The purpose of this study was to investigate the morphological characteristics of different brands of lentinan injections produced in China using atomic force microscopy (AFM) and their relationship to immunological activity. Based on AFM imaging, chain height could be used as characterizing the conformation of lentinan, and the heights of 95 % confidence interval for triple, double and single helix were 1.746 ± 0.039 nm, 1.564 ± 0.037 nm and 1.243 ± 0.031 nm, respectively, which were calculated using self-developed MATLAB protocol. AFM characters and their immunological activity of different lentinan injection were compared. In detail, two parameters, triple helix ratio 51.3 % and adhesion force 800 pN, of Jinling (JL) lentinan injection are much higher than samples of other four manufacturers. In addition, immunological activity of JL lentinan injection is also significantly higher than Yineng's. High performance size exclusion chromatography (HPSEC) profiles of different lentinans were also compared, and the data were in accordance with those from AFM. Molecular weight accumulation curves could be used for evaluation of quality consistence of different batches of lentinan from same manufacturer and/or different manufacturers. The results showed that quality consistence of lentinan from different manufactures is poor, which should be greatly improved.

Lentinan has a beneficial effect on cognitive deficits induced by chronic Toxoplasma gondii infection in mice

BACKGROUND

Toxoplasma gondii (T. gondii) is increasingly considered a risk factor for neurodegenerative diseases. However, there is only limited information on the development of drugs for T. gondii infection. Lentinan from Lentinula edodes is a bioactive ingredient with the potential to enhance anti-infective immunity. The present study aimed to investigate the neuroprotective effect of lentinan on T. gondii-associated cognitive deficits in mice.

METHODS

A chronic T. gondii infection mouse model was established by administering 10 cysts of T. gondii by gavage. Lentinan was intraperitoneally administered 2 weeks before infection. Behavioral tests, RNA sequencing, immunofluorescence, transmission electron microscopy and Golgi-Cox staining were performed to assess the effect of lentinan on cognitive deficits and neuropathology in vivo. In vitro, the direct and indirect effects of lentinan on the proliferation of T. gondii tachyzoites were evaluated in the absence and presence of BV-2 cells, respectively.

RESULTS

Lentinan prevented T. gondii-induced cognitive deficits and altered the transcriptome profile of genes related to neuroinflammation, microglial activation, synaptic function, neural development and cognitive behavior in the hippocampus of infected mice. Moreover, lentinan reduced the infection-induced accumulation of microglia and downregulated the mRNA expression of proinflammatory cytokines. In addition, the neurite and synaptic ultrastructural damage in the hippocampal CA1 region due to infection was ameliorated by lentinan administration. Lentinan decreased the cyst burden in the brains of infected mice, which was correlated with behavioral performance. In line with this finding, lentinan could significantly inhibit the proliferation of T. gondii tachyzoites in the microglial cell line BV2, although lentinan had no direct inhibitory effect on parasite growth.

CONCLUSIONS

Lentinan prevents cognitive deficits via the improvement of neurite impairment and synaptic loss induced by T. gondii infection, which may be associated with decreased cyst burden in the brain. Overall, our findings indicate that lentinan can ameliorate T. gondii-related neurodegenerative diseases.

Lentinan alleviates diabetic cardiomyopathy by suppressing CAV1/SDHA-regulated mitochondrial dysfunction

Diabetic cardiomyopathy (DCM), characterized by mitochondrial dysfunction and impaired energetics as contributing factors, significantly contributes to high mortality in patients with diabetes. Targeting key proteins involved in mitochondrial dysfunction might offer new therapeutic possibilities for DCM. Lentinan (LNT), a β-(1,3)-glucan polysaccharide obtained from lentinus edodes, has demonstrated biological activity in modulating metabolic syndrome. In this study, the authors investigate LNT's pharmacological effects on and mechanisms against DCM. The results demonstrate that administering LNT to db/db mice reduces cardiomyocyte apoptosis and mitochondrial dysfunction, thereby preventing DCM. Notably, these effects are fully negated by Caveolin-1 (CAV1) overexpression both in vivo and in vitro. Further studies and bioinformatics analysis uncovered that CAV1 bound with Succinate dehydrogenase subunit A (SDHA), triggering the following ubiquitination and degradation of SDHA, which leads to mitochondrial dysfunction and mitochondria-derived apoptosis under PA condition. Silencing CAV1 leads to reduced apoptosis and improved mitochondrial function, which is blocked by SDHA knockdown. In conclusion, CAV1 directly interacts with SDHA to promote ubiquitination and proteasomal degradation, resulting in mitochondrial dysfunction and mitochondria-derived apoptosis, which was depressed by LNT administration. Therefore, LNT may be a potential pharmacological agent in preventing DCM, and targeting the CAV1/SDHA pathway may be a promising therapeutic approach for DCM.

Lentinan alleviates sciatic nerve injury by promoting autophagy to remove myelin fragments

Lentinan, a natural drug with wide-ranging pharmacological activities, can regulate autophagy-the process through which Schwann cells (SCs) eliminate myelin fragments after peripheral nerve injury (PNI). However, the effect of lentinan after PNI and the role of accelerated myelin debris removal via autophagy in this process are unclear. This study examined the effect of lentinan on rat sciatic nerve repair following crush injury and the underlying mechanisms. After the successful establishment of the sciatic nerve compression injury model, group-specific treatments were performed. The treatment group received 20 mg/kg lentinan via intraperitoneal injection, while the model group was treated with normal saline. The recovery in each group was then evaluated. Further, a rat SC line (RSC96) was cultured in medium with/without lentinan after supplementation with homogenous myelin fractions to evaluate the removal of myelin particles. Our results showed that lentinan promotes autophagic flux in vivo via the AMPK/mTOR signaling pathway, accelerates the clearance of myelin debris by SCs, and inhibits neuronal apoptosis, thereby promoting neurological recovery. Similarly, in vitro experiments showed that lentinan promotes the phagocytosis of myelin debris by SCs. In conclusion, our results suggest that lentinan primarily promotes nerve regeneration by accelerating the autophagic clearance of myelin debris in SCs, and this process is likely regulated by the AMPK/mTOR signaling pathway. Therefore, this study provides compelling evidence that lentinan may be a cost-effective and natural treatment agent for PNI.

Effect of lentinan on proliferation and apoptosis of human astrocytoma U251 cells

AIM OF THE STUDY

Aim of the study is To investigate the effect of lentinan on proliferation and apoptosis of human astrocytoma U251 cells. Lentinan was dissolved in DMEM complete medium to form different concentrations (0, 25, 50, 100, 200, 400, 500, 600 µg/ml). CCK8 was used to detect the effect of lentinan with different concentrations on proliferation of human astrocytoma U251 cells, and the expression of Ki-67 was detected by immunofluorescence. In addition, the effect of different concentrations of lentinan on apoptosis of human astrocytoma U251 cells was detected by flow cytometry. Compared with the blank control group, 50 and 100 µg/ml lentinan significantly promoted proliferation of human astrocytoma U251 cells. When the concentration is more than 100 µg/ml, the cell activity gradually decreases, and the cell activity is the lowest when the concentration is 600 µg/ml. In addition, the low concentration lentinan (25, 50, and 100 µg/ml) had no significant effect on apoptosis of human astrocytoma U251 cells. However, lentinan above 200 µg/ml significantly promoted apoptosis of human astrocytoma U251 cells and had a concentration gradient effect, and the highest apoptosis rate was at 600 µg/ml.

CONCLUSIONS

Lentinan can effectively inhibit proliferation and promote apoptosis of human astrocytoma U251 cells.

Lentinan Enhances the Function of Oxaliplatin on the Esophageal Tumors by Persuading Immunogenic Cell Death

Objective

The focus of this research was to look at the effects of the combination of the lentinan (LNT) and oxaliplatin (Oxa) on the apoptosis of human esophageal cancer cells, as well as the underlying mechanism.

Methods

LNT and Oxa were used to treat EC-109 human esophageal cancerous cells at various doses, and the cell survival rate was measured using the Cell Counting Kit-8 (CCK-8) assay. In addition, 24 h after treatment of EC-109 cells with a combination of LNT and Oxa, flow cytometry was used to analyze their apoptotic effect on these cells. Additionally, LNT on EC-109 cell apoptotic upshot was assessed via measuring the consequence of LNT on the mRNA and protein expression levels pertaining to immunogenic cell death factors CALR, HSP90, and HSP70 by qPCR (quantitative real-time polymerase chain reaction) and western blot analysis, correspondingly.

Results

Cell proliferation was inhibited only when EC-109 cells were added with LNT at 1,200 μg/mL to the maximum concentrations, but the combination of LNT and Oxa at a low dose (800 μg/mL and 20 μM, respectively) significantly increased their sensitivity to Oxa and reduced their proliferation (P < 0.05), and their apoptosis was significantly increased by LNT (P < 0.05). The immunogenic cell death-related genes CALR, HSP90, and HSP70 had dramatically enhanced mRNA and protein expression levels after therapy with a combination of LNT and Oxa (P < 0.05).

Conclusion

These data imply that LNT increases the susceptibility of esophageal cancerous cells to Oxa by driving EC-109 cells to display immunogenic death. Therefore, LNT combined with Oxa may be an effective method in esophageal cancer management.

Anti-Influenza Effect and Mechanisms of Lentinan in an ICR Mouse Model

Influenza virus is a serious threat to global human health and public health security. There is an urgent need to develop new anti-influenza drugs. Lentinan (LNT) has attracted increasing attention in recent years. As potential protective agent, LNT has been shown to have anti-tumor, anti-inflammatory, and antiviral properties. However, there has been no further research into the anti-influenza action of lentinan in vivo, and the mechanism is still not fully understood. In this study, the anti-influenza effect and mechanism of Lentinan were studied in the Institute of Cancer Research (ICR) mouse model. The results showed that Lentinan had a high degree of protection in mice against infection with influenza A virus, delayed the emergence of clinical manifestations, improved the survival rate of mice, significantly prolonged the middle survival days, attenuated the weight loss, and reduced the lung coefficient of mice. It alleviated the pathological damage of mice infected with the influenza virus and improved blood indices. Lentinan treatment considerably inhibited inflammatory cytokine (TNF-α, IL-1β, IL-4, IL-5, IL-6) levels in the serum and lung and improved IFN-γ cytokine levels, which reduced cytokine storms caused by influenza virus infection. The underlying mechanisms of action involved Lentinan inhibiting the inflammatory response by regulating the TLR4/MyD88 signaling pathway. This study provides a foundation for the clinical application of Lentinan, and provides new insight into the development of novel immunomodulators.

Lentinan combined with cisplatin for the treatment of non-small cell lung cancer

BACKGROUND

A growing number of studies suggest that lentinan combined with cisplatin thoracic injection for the treatment of lung cancer is an effective combination of traditional Chinese and Western medicine, which has a continuous and beneficial effect on eliminating clinical symptoms and improving cachexia in lung cancer patients. However, whether this treatment is effective and safe for lung cancer patients or not, evidence supporting the effectiveness and safety of this treatment is still incomplete. Besides, there is lack of systematic review to assess the detailed situation (including risk of bias and methodology) of current related clinical studies.

OBJECTIVE

This study aimed to evaluate the effectiveness and safety of lentinan combined with cisplatin thoracic injection in the treatment of lung cancer.

METHODS

The major databases (Embase, PubMed, the Cochrane Library, China National Knowledge Infrastructure, Chinese Scientific Journals Database [VIP] Database, Chinese Biomedical Literature Service System [SinoMed], and Wanfang Database) were searched from inception to March 1, 2020. Randomized controlled trials (RCTs) of lentinan combined with cisplatin chest injection on patients with non-small cell lung cancer (NSCLC) were identified. Two assessors reviewed each trial independently. The methodological quality of the eligible studies was evaluated according to the Cochrane Collaboration's tool for assessing risk of bias. Both the data extraction and the literature quality screening evaluation were conducted independently by 2 researchers.

RESULTS

Totally 17 clinical RCTs were included in this study, involving 1390 patients. Meta-analysis results showed that the clinical efficacy (risk ratio [RR] = 1.34, 95% confidence interval [CI] 1.21-1.48), effective subgroup analysis (RR = 1.51, 95% CI 1.3-1.77), and quality of life (RR = 1.48, 95% CI 1.27-1.72), the differences are statistically significant. In terms of adverse reactions, mainly related to gastrointestinal reactions and bone marrow suppression, the incidence and degree of adverse reactions of lentinan combined with cisplatin thoracic injection group were lower than those of cisplatin thoracic injection group alone.

CONCLUSIONS

The current evidence prompted that Lentinan combined with cisplatin in thoracic injection might benefit patients with NSCLC on a certain extent; this systematic review revealed some definite conclusions about the application of Lentinan combined with cisplatin in thoracic injection for NSCLC. Due to the low methodological quality, high risk of bias, and inadequate reporting on clinical data, these results still require verification by a large number of well designed, heterogeneous RCT studies. More rigorous, multicenter, sufficient-sample, and double-blind RCTs are warranted.

Dual-Action Pesticide Carrier That Continuously Induces Plant Resistance, Enhances Plant Anti-Tobacco Mosaic Virus Activity, and Promotes Plant Growth

Improving plant resistance against systemic diseases remains a challenging research topic. In this study, we developed a dual-action pesticide-loaded hydrogel with the capacity to significantly induce plant resistance against tobacco mosaic virus (TMV) infection and promote plant growth. We produced an alginate-lentinan-amino-oligosaccharide hydrogel (ALA-hydrogel) by coating the surface of an alginate-lentinan drug-loaded hydrogel (AL-hydrogel) with amino-oligosaccharide using electrostatic action. We determined the formation of the amino-oligosaccharide film using various approaches, including Fourier transform infrared spectrometry, the ζ potential test, scanning electron microscopy, and elemental analysis. It was found that the ALA-hydrogel exhibited stable sustained-release activity, and the release time was significantly longer than that of the AL-hydrogel. In addition, we demonstrated that the ALA-hydrogel was able to continuously and strongly induce plant resistance against TMV and increase the release of calcium ions to promote Nicotiana benthamiana growth. Meanwhile, the ALA-hydrogel maintained an extremely high safety to organisms. Our findings provide an alternative to the traditional approach of applying pesticide for controlling plant viral diseases. In the future, this hydrogel with the simple synthesis method, green synthetic materials, and its efficiency in the induction of plant resistance will attract increasing attention and have good potential to be employed in plant protection and agricultural production.

Conformation-Dependent Manipulation of Human Islet Amyloid Polypeptide Fibrillation by Shiitake-Derived Lentinan

Misfolding and aggregation of human islet amyloid polypeptide (hIAPP) into fibrils are important contributions to the pathology of type 2 diabetes. Developing effective inhibitors of protein aggregation and fibrillation has been considered a promising therapeutic approach to preventing and treating type 2 diabetes. Herein, we report that Shiitake-derived polysaccharide lentinan manipulates in vitro hIAPP fibrillation and modulates IAPP-induced cytotoxicity in a conformation-dependent manner. In its triple-helical conformation, lentinan effectively inhibits hIAPP fibrillation, either in bulk solution or in the presence of lipid membrane, suppresses reactive oxygen species (ROS) generation, and attenuates hIAPP-induced cell toxicity. In contrast, lentinan accelerates hIAPP aggregation when it exists in a random-coil conformation and shows no suppression on hIAPP-mediated ROS production. Further investigation shows that the interaction between triple-helical lentinan and monomeric hIAPP is more favorable than the intermolecular binding of hIAPP, which redirects hIAPP aggregates to discrete nontoxic nanocomposites. To the best of our knowledge, this is the first time to report a conformation-dependent inhibition of hIAPP aggregation, which will provide new insights for our understanding of the manipulation mechanisms on hIAPP by natural polysaccharides and open a new avenue for designing and screening potential amyloid inhibitors against type 2 diabetes.

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.

Apoptosis-inducing effects of lentinan on the proliferation of human bladder cancer T24 cells

The aim of this study was to explore the effects of lentinan on the proliferation of human bladder cancer T24 cells and the mechanism regarding the inhibition of cell growth. When gene regulation technique was used to build pcDNA3-TRPM8 expression plasmid, TRPM8 channel activator-lentinan was used for intervention to observe the proliferation of T24 cells. Flow cytometry cell screening method was used to observe the cell ratio of each cell cycle of T24 cells and the ratio of apoptotic and dying cells under the intervention of different concentrations of lentinan using PI single-staining and Annexin V-FITC/PI double-staining. JC-1 and DCFH-DA fluorescence probes were used to observe the influence of different concentrations of lentinan on the mitochondrial membrane potential of T24 cells and intracellular reactive oxygen species (ROS) by confocal microscope. pcDNA-TRPM8 plasmid was successfully constructed, and lentinan could inhibit the growth of T24 cells in a dose-dependent pattern. Lentinan played its biological effect through TRPM8 channel to further inhibit the growth of T24 cells, reduced the mitochondrial membrane potential of bladder cancer T24 cell line, and increased the generation of ROS in human bladder cancer T24 cell line. Lentinan led to mitochondrial depolarization or activation of non-mitochondrial pathway to induce intracellular ROS generation, thus eventually inducing T24 cell death and growth inhibition.

Inhibitory effects of sulfated lentinan with different degree of sulfation against tobacco mosaic virus (TMV) in tobacco seedlings

The inhibitory effects of sulfated lentinan with different degrees of sulfation against tobacco mosaic virus (TMV) and the underlying mechanism were investigated. The results indicated that plants treated with increasing concentrations of sulfated lentinan, with increasing numbers of treatments and with increasing time after treatment had a decrease in the number of necrotic lesions, indicating a long-term protection against TMV that mimics vaccination. In addition, the levels of TMV-capsid protein (CP) transcripts decreased in distant leaves, indicating that sulfated lentinan induces systemic protection against TMV. The activities of the defense enzymes phenylalanine ammonia lyase (PAL) and lipoxygenase (LOX) and the amounts of several phenylpropanoid compounds (PPCs) were measured in control and treated plants without infection. A progressive increase in PAL activity was observed with increasing time after treatment, together with the accumulation of free and conjugated PPCs. In contrast, LOX activity remained unchanged. Interestingly, the increase in PAL activity showed a linear correlation with the decrease in necrotic lesions and the decrease in TMV-CP transcript level. Thus, sulfated lentinan induced systemic and long-term protection against TMV in tobacco plants that is determined, at least in part, by a sustained activation of PAL and the accumulation of PPCs with potential antiviral activity.

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.

Effect of lentinan on membrane-bound protein expression in splenic lymphocytes under chronic low-dose radiation

We investigated the protective effects of lentinan against damages to chronic and low-dose radiation (CL-radiation) by using mouse models. The mice were randomized divided into four groups: normal control mice (Ctr), mice exposed to radiation (Rad), irradiated mice treated with low-dose lentinan (0.1mg/(kg.d), RL), and irradiated mice treated with high-dose lentinan (0.5mg/(kg.d), RH). All the mice were injected intraperitoneally once a day at a dose of 0.5mL (Ctr and Rad with normal sodium while RL and RH with lentinan). The success of radiation models was confirmed by HE stain and cell morphology by a transmission electron microscope (TEM). On the basis of radiation models, we investigated the expression of proteins on the membrane of splenic cells through MALDI-TOF-MS/MS. The results demonstrated that both RT-radiation and lentinan affected the expression of membrane proteins, but lentinan protected the splenic cells and tissue from the injuries caused by CL-radiation. Therefore, we speculated that CL-radiation mainly damages the genetic materials and membrane-bound proteins, while lentinan protects membrane-bound proteins by regulating signal transduction and the appearance of the cells.

Inhibition of aflatoxin synthesis in Aspergillus flavus by three structurally modified lentinans

The chemical properties of β-glucans leading to their inhibition on aflatoxin (AF) production by Aspergillus flavus remain unclear. In this study, structurally modified lentinan derivatives were prepared by carboxymethylation, sulfation, and phosphorylation to explore their inhibition activity to AF synthesis. The results demonstrated that inhibitory activity of lentinan decreased at higher or lower concentrations than 200 μg/mL. Compared with lentinan, the sulphated derivatives only performed a reduced optimal inhibition rate at a higher concentration. The phosphorylated derivatives achieved complete inhibition of AF production at 50 μg/mL, but the inhibitory activity was attenuated with an increase of concentration. The minimum concentration of carboxymethylated derivatives to completely inhibit AF synthesis was the same as that of the original lentinan, whereas their inhibition activity was not reduced at the increasing concentration. RT-PCR analyses were conducted to understand the effects of lentinan and its carboxymethylated derivatives on the transcription of certain genes associated with AF biosynthesis. The results showed that lentinan delayed the transcription of aflQ, whereas its carboxymethylated derivatives promoted the transcriptions of all the tested genes. Our results revealed that some chemical group features apart from the β-bond could play the vital role in the prevention of AF formation by polysaccharide, and highlighted the structural modifications which could promote its practicability in the control of aflatoxin contamination.

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.

Intestinal anti-inflammatory activity of lentinan: influence on IL-8 and TNFR1 expression in intestinal epithelial cells

Inflammatory bowel disease (IBD) is characterized by chronic inflammation of the gastrointestinal tract. It is unknown whether β-1,3;1,6-glucan can induce immune suppressive effects. Here, we study intestinal anti-inflammatory activity of Lentinula edodes-derived β-1,3;1,6-glucan, which is known as lentinan. Dextran sulfate sodium (DSS)-induced colitis mice were used to elucidate effects of lentinan in vivo. In the cellular level assessment, lentinan was added into a co-culture model consisting of intestinal epithelial Caco-2 cells and LPS-stimulated macrophage RAW264.7 cells. Ligated intestinal loop assay was performed for assessing effects of lentinan on intestinal epithelial cells (IECs) in vivo. Oral administration of lentinan (100 µg/mouse) significantly ameliorated DSS-induced colitis in body weight loss, shortening of colon lengths, histological score, and inflammatory cytokine mRNA expression in inflamed tissues. Lentinan reduced interleukin (IL)-8 mRNA expression and nuclear factor (NF)-κB activation in Caco-2 cells without decreasing of tumor necrosis factor (TNF)-α production from RAW264.7 cells. Flow cytometric analysis revealed that surface levels of TNF receptor (TNFR) 1 were decreased by lentinan treatment. A clathrin-mediated endocytosis inhibitor, monodansylcadaverine, canceled lentinan inhibition of IL-8 mRNA expression. Moreover, lentinan inhibited TNFR1 expression in Caco-2 cells in both protein and mRNA level. Lentinan also inhibited TNFR1 mRNA expression in mouse IECs. These results suggest that lentinan exhibits intestinal anti-inflammatory activity through inhibition of IL-8 mRNA expression associated with the inhibition of NF-κB activation which is triggered by TNFR1 endocytosis and lowering of their expression in IECs. Lentinan may be effective for the treatment of gut inflammation including IBD.

[Effect of lentinan against immunosuppression of lymphocytes cultured in simulated microgravity environment]

This study was aimed to evaluate the effect of lentinan on the immune function of splenic lymphocytes in rotary cell culture system (RCCS) microgravity environment. The splenic lymphocytes from mice were separated and cultured in the normal gravity and the microgravity environments. The cells were treated with lentinan solution (0, 10, 20 and 40 µg/ml). After incubated with lentinan for indicated times (24, 48 and 72 h), the cell proliferation, secretion of cytokine and the expression of cell surface markers were detected by MTT method, ELISA and flow cytometry respectively. The results indicated that lentinan of above mentioned concentrations did not obviously promote the lymphocyte proliferation, but increased the secretion of IL-2 and IFN-γ and enhanced the expression of lymphocyte surface markers CD4 and CD8 in microgravity environment. It is concluded that lentinan has the ability to enhance the lymphocyte immune function in microgravity environment.

[Effects of lentinan on interleukin-1β-induced transdifferentiation of human embryonic lung fibroblasts to myofibroblasts]

OBJECTIVE

To study the effects of interleukin-1β (IL-1β) on transdifferentiation of human embryonic lung fibroblasts to myofibroblasts and the effects of lentinan on the transdifferentiation.

METHODS

The human embryonic lung fibroblasts were cultured in vitro, and fibroblasts were treated with different concentrations of IL-1β and lentinan. The proliferation activity of the human embryonic lung fibroblasts was evaluated by the Cell Counting Kit-8 (CCK-8). The expression of α-smooth muscle actin (α-SMA) protein was measured by immunocytochemistry. The levels of fibronectin (FN), typeⅠcollagen (ColⅠ) and α-SMA mRNA were detected by RT-PCR.

RESULTS

Compared with the untreated control group, the absorbance value of cell proliferation, α-SMA protein levels, FN, ColⅠand α-SMA mRNA expression were significantly up-regulated after different concentrations of IL-1β (0.1, 1, 10 ng/mL) treatment for 48 hrs (P<0.01). Lentinan treatment inhibited up-regulation of the cell proliferation activity, α-SMA protein levels, FN, ColⅠand α-SMA mRNA expression induced by IL-1β in a dose-independent manner (P<0.01).

CONCLUSIONS

Lentinan can suppress human embryonic lung fibroblast proliferation, fibroblast-myofibroblast transdifferentiation and extra cellular matrix synthesis induced by IL-1β.

[Lentinan induces the expression of human-beta-defensin-2 in pulmonary epithelial cells]

To determine whether lentinan could upregulate the expression of human-beta-defensin-2(HBD-2) in pulmonary epithelial cells (SPC-A-1), we stimulated pulmonary epithelial cells with lentinan and detected the expression of HBD-2mRNA by RT-PCR test. The results demonstrated that the expression of HBD-2mRNA in SPC-A-1 could be induced by lentinan in a concentration and time-dependent manner.

Modulation of splenic immune responses to bacterial lipopolysaccharide in rainbow trout (Oncorhynchus mykiss) fed lentinan, a beta-glucan from mushroom Lentinula edodes

Immunostimulants (IS) are considered a promising approach for improving resistance to pathogens in fish aquaculture. At present, development of IS are complicated due to limited knowledge on the mechanisms of their action. To assess the use of global gene expression analysis for screening of candidate IS we applied lentinan, a beta-glucan from the mushroom Lentinula edodes, as a model. After feeding rainbow trout (Oncorhynchus mykiss) with lentinan-supplemented (L) and control (C) diets for 37 days, fish were injected with bacterial lipopolysaccharide (LPS), a classical inducer of inflammation. Gene expression was analyzed in LPS-challenged compared to saline-injected fish using a salmonid 1.8k cDNA microarray (SFA2.0 immunochip) and real-time qPCR. Spleen was selected for data analyses due to highest magnitude of responses and its key role in the fish immune system. A group of genes implicated in acute inflammatory responses was higher induced in C versus L, including IFN-related and TNF-dependent genes (galectins and receptors, signal transducers and transcription factors), genes involved in MHC class I antigen presentation and leukocyte recruitment. A similar trend was observed in metabolism of iron and xenobiotics, markers of oxidative and cellular stress. Interestingly, differences between C and L were similar to those observed between salmon with low and high resistance to infectious salmon anemia virus. Genes with equal responses to LPS in L and C were related to cell communication (cytokines, chemokines and receptors), signal transduction, activation of immune cells, apoptosis, cellular maintenance and energy metabolism. In conclusion, lentinan decreased the expression of genes involved in acute inflammatory reactions to the inflammatory agent while major parts of the immune response remained unchanged. Such effects are expected for IS, which should modify immunity by enhancing beneficial and reducing detrimental responses.

[Effects of six polysaccharides extracted from plants on the immunological cells of mice]

OBJECTIVE

To compare the immunoenhancement of six polysaccharides on the murine immunological cells in vitro.

METHODS

The immunoenhancement of the polysaccharide on the murine splenocytes were tested by MTt assay. The effects of polysaceharides on IgG secretion of spleen lymphocytes were detected by ELISA. The activation of peritoneal macrophages were tested by the method of neutral red phagocytosis assay. The phagocytic activity of spleen NK cells were detected by the method of LDH.

RESULTS

Lentinan and Ganoderan could promote spleen lymphocyte proliferation with ConA significantly. Astragalan, Ganoderan and Lentinan had stronger function in promoting the IgG secretion and proliferation of spleen lymphocyte with LPS. Lichenan and Astragalan could significantly enhance activation of peritoneal macrophages and splenic NK.

CONCLUSION

The immuno-regulation mechanism and effects of six polysaccharides were indivadually variable. The polysaccharide aiming at different effect targets could be combined into the most immunopotentiating agent by the most appropriate doses ratio.

Enhancing effects of new biological response modifier beta-1,3 glucan sulfate PS3 on immune reactions

Glucans have a long history as non-specific biological modulators; however, but the search for optimal chemical configuration is still on. The objective of this study was to evaluate intraperitoneal application of PS3, a sulfated derivative of a (1-->3)-beta-D-glucan isolated from sporophytes of Laminaria digitata. PS3 showed significant stimulation of phagocytic activity as well as potentiation of synthesis and release of IL-2 by splenocytes. In addition, PS3 increased NK cell-mediated killing of tumor cells both in vitro and in vivo. When combined, our observations suggest that PS3 is similarly effective as native non-sulfated (1-->3)-beta-D-glucan and is generally more active than lentinan.

[Establishment of a transgenic cell model for preliminary screening of chemopreventive agents]

To develop a GFP transgenic cell model under the transcriptional control of TK promoter adjacent to which ARE enhancer was inserted. Synthetic oligonucleotide ARE motif was annealed and purified then inserted into pTK-GFP to construct the vector of pARE-TK-GFP. The TK and ARE-TK fragments were amplified by PCR and cloned into pEGFP-N1 to reconstruct eukaryotic expression vectors of pTK-GFP/Neo and pARE-TK-GFP/Neo. They were transfected into HepG2 cells and clones resistant G418 were isolated. PDTC and Lentinan were used to induce the cell levels of GFP and the fluorescence was measured using a fluorescence plate reader. The results showed that the induced level of GFP is significantly increased and have dose-dependeny in a certain range. This findings indicated that such a cell model offered a potential platform for preliminary screening of all kinds of natural or synthetic chemopreventive agents.

[Study on effect of lentinan in enhancing anti-tumor action of dendritic cytoma vaccine and its mechanism]

OBJECTIVE

To improve the anti-tumor effect of dendritic cytoma vaccine (DCV) for finding an effective anti-tumor biotherapy.

METHODS

DC vaccine prepared by transfection of adenovirus mediated melanoma-associated antigen gene (gp100) into bone marrow-derived dendritic cell (DC) was used to study the immuno-therapeutic effect and the mechanism of lentinan (LNT) in different dosages, used alone or combined with gp100-DC for treatment of B16 melanoma bearing mice.

RESULTS

After being treated with LNT combining gp100-DC, the growth of malignant melanoma was inhibited with the tumor-free survival in the experimental animals being 66.7%. The treatment could also significantly enhance the activity of cytotoxicity T lymphocyte (CTL) and natural killer (NK) cells, elevate the levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in splenocytes, and histological examination showed that a large amount of inflammatory cells infiltrated inside and around the tumor, and obvious necrosis of tumor cells was found.

CONCLUSION

By combined use with LNT the anti-tumor immuno-reaction of DCV vaccine could be enhanced effectively.

[Anti tumor activities of lentinan and micellapist in tumor-bearing mice]

Although Lentinan (LNT) is sold as a medicine, and Micellapist (MME) sold as a food supplement, both LNT and MME are beta-glucans isolated from the Shiitake mushroom (Lentinula edodes). These two substances have been thought to be the same component of Shiitake. In the present study, we evaluated anti tumor activities of LNT and MME in tumor-bearing mice (B10.D2 mice implanted with S908D2 tumor cells) and examined the mechanism of immunopotentiation of these substances. The tumor growth was significantly suppressed in the LNT-treated group. In ex vivo evaluation, the tumor cytotoxicity was significantly reduced by a treatment of splenocytes with anti-CD8 antibody in the LNT-treated group. Furthermore, the tumor cytotoxicity of the LNT-treated group was also significantly reduced by a treatment of splenocytes with anti-CD8 antibody and its complement and with an anti-CD4 and its complement in the effector phase and the induction phase, respectively. A significant prolongation of the survival of tumor-bearing mice as compared to the untreated control group was noted in the LNT-treated group. In the mice treated intraperitoneally with LNT, CD8-positive cells appeared to have suppressed tumor cell proliferation. CD4-positive cells appeared to be involved in this activity of CD8-positive cells. On the other hand, orally administered MME has exerted no clear cytotoxic effects.

Cancer chronomics III. Chronomics for cancer, aging, melatonin and experimental therapeutics researchers

This position paper documents the merit of including for basic and clinical investigations the mapping of circadian and other rhythms and yet broader chronomes, time structures in and around us. Chronobiometry used herein relies on inferential statistical methods and on materials documented earlier. The circadian amplitude of melatonin is shown to relate both to cancer risk and to the presence of overt cancer, when no differences are found in the 24-hour average of melatonin. Optimization of treatment by timing, thoroughly documented along the circadian scale earlier, could be broadened to include optimization along the scale of the week, and eventually beyond. In both cases, reliance on marker rhythmometry is advocated. More generally, the limits of knowledge are expanded by considering already mapped spectral components and their characteristics that can be influenced by the dynamics of heliogeomagnetic signals heretofore unassessed.

Lentinan has a stimulatory effect on innate and adaptive immunity against murine Listeria monocytogenes infection

Lentinan, a (1-3)-beta glucan from Lentinus edodes, is licensed as an immunostimulatory drug. We tested the effect of lentinan in the well-established model system of the murine Listeria monocytogenes infection. Pre-treatment of bone marrow macrophages and dendritic cells with lentinan resulted in increased production of TNF-alpha and IL-12 after L. monocytogenes infection in vitro. After lentinan treatment bone marrow macrophages showed increased NO-production and enhanced cytotoxic activity against L. monocytogenes. Pre-treatment of mice with lentinan resulted in increased concentrations of TNF-alpha, IL-12 and IFN-gamma and also an increased number of L. monocytogenes specific CD8 T cells in the spleen. The bacterial burden in spleen and liver of mice was significantly reduced during primary and secondary Listeria infection after lentinan pre-treatment of mice. In summary these results show that lentinan enhances the protective CD8 T-cell response against L. monocytogenes probably by a mechanism that involves the IL-12-mediated augmentation of the specific antilisterial CD8 T-cell response.

[Antitumor effects of intratumoral injection of Basidiomycetes preparations]

The antitumor effects of Basidiomycetes preparations in an experimental mouse model, the "double grafted tumor system" were analyzed. Some BRMs prevented metastases by utilizing the anti-tumor immunological cascade reactions, which activates macrophages in the body. The following Basidiomycetes preparations were analyzed: PSK was a hot water extract of cultured mycelia from Coliolus versicolor and a protein bound beta-glucan. Matsumax was extracted from mycelia of Tricholoma matsutake and was a protein bound (38%) a-glucan. The Agaricus preparation was extracted from fruit bodies of Agaricus blazei and a protein-bound (17%) a-glucan, beta-glucan. Himematsutake preparation was extracted from fruit body of Agaricus blazei (Himematsutake) and a protein bound (5%) glucan. Lentinan was purified from fruit bodies of Lentinus edodes and is a purified beta-glucan. PSK cured both primary and metastatic tumors in the double grafted tumor system. Lentinan inhibited the growth of neither primary nor metastatic tumors. Matsumax and Agaricus preparation cured primary tumor and inhibited the growth of metastatic tumor. Himematsutake preparation inhibited the growth of primary tumor. Immunosuppresive acidic protein (IAP) is produced by activated mactrophates. The PSK, Matsumax, Agaricus preparation and Himematsutake preparation induced IAP but Lentinan did not.

Correlation between antitumor activity, molecular weight, and conformation of lentinan

A (1-->3)-beta-D-glucan having (1-->6) branching (L-FV-IB) from Lentinus edodes in water was degraded into seven fractions of different molecular weights by ultrasonic irradiation, and each was further fractionated into three parts, by precipitation from water into acetone at room temperature. The weight-average molecular weight (M(w)), radius of gyration (<S(2)>(z)(1/2)), and intrinsic viscosity ([eta]) of lentinan and its fractions in 0.9% NaCl aqueous solution and dimethyl sulfoxide (Me(2)SO) were determined by size-exclusion chromatography combined with multi-angle laser light scattering (SEC-LLS), LLS, and viscometry. Analysis of M(w), [eta], and <S(2)>(z)(1/2) in terms of known theory for worm-like chains yielded 2240 +/- 100 nm(-1), and 100 +/- 10 nm for molar mass per unit contour length (M(L)), and persistence length (q), respectively, corresponding with theoretical data for triple-helical chains. The [alpha](D) of lentinan in water-Me(2)SO mixtures indicated an order-disorder transition. The results indicated that lentinan exists as a triple helix in 0.9% NaCl aqueous solution and as a single flexible chain in Me(2)SO. Assays in vivo and in vitro against the growth of Sarcoma 180 solid tumor as well as the colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method for lentinan showed that the triple-helix sample exhibited a relatively high inhibition ratio. Interestingly, the triple-helix lentinan with M(w) of 1.49 x 10(6) exhibited the highest antitumor activity in vivo, having an inhibition ratio (xi) of 49.5%, close to that of 5-fluorouracil (xi = 50.5%), whereas the bioactivity (xi = 12.3%) of its single flexible chains almost disappeared. The triple-helix conformation plays an important role in enhancing the antitumor effects of lentinan.

Combined immunomodulating effects of BCG and Lentinan after intranasal application in guinea pigs

The ability of a Shiitake (Lentinus edodes) medical mushroom-derived bioactive polymer Lentinan (Ajinomoto, Japan) to modulate the immune response makes it a potential candidate for combination therapy with BCG, or as adjunct for BCG vaccination, especially in high-risk individuals. We studied the combined immune-potential effectiveness of intranasal application of Lentinan (at a dose of 1 mg/kg, three times at 2-day intervals), followed by administration of BCG (strain Sofia SL-222 at a dose of 1 x 10(8) CFU, once) in guinea pigs. Samples of broncho-alveolar lavage fluid, as well as tissue fragments of lungs, spleens and lymph nodes were obtained from four groups (combined treatment with Lentinan and BCG; only with Lentinan; only with BCG; control with saline) of animals at different intervals--1, 14 and 45 days after last treatment and were evaluated by several parameters (establishing the number, H2O2 and nitrite production, and killing ability against Mycobacterium tuberculosis and Staphylococcus aureus of alveolar macrophages; spleen index, BCG CFU in spleens and histomorphological observations). Our attention was focused both on local effects in lungs, and systematical effects in reticuloendothelial system. The results indicate that intranasal application of BCG alone, or in combination with Lentinan induced high level of alveolar macrophage activation. Pre-treatment with Lentinan enhanced the local immunohistological response to BCG in lung and reduced the generalized side effects.

Intranasal application of lentinan enhances bactericidal activity of rat alveolar macrophages against Mycobacterium tuberculosis

To study the in vivo interaction between lentinan-stimulated alveolar macrophages and Mycobacterium tuberculosis were used rats intranasally infected with 2 x 10(8) CFU. Before infection animals were treated intranasally with lentinan at a dose of 1 mg/kg (administrated three times at 2 days periods). Samples of broncho-alveolar lavage fluid were obtained from rats at different intervals -3, 24 and 72 h after infection. The process of phagocytosis in vivo was observed by light and electron microscopy, as well as acid phosphatase cytochemistry methods. Bactericidal activity of alveolar macrophages following the same intranasal installation of lentinan was assessed by in vitro "killing" ability test against M. tuberculosis. Nitrite production by lentinan activated alveolar macrophages was measured 24 h after ex vivo culture of these cells. It was demonstrated that lentinan induces high level of alveolar macrophage activation manifested through enhanced bactericidal effect against M. tuberculosis, which correlates with the induction of reactive nitrogen intermediates, increased activity of lysosomal enzymes (acid phosphatase), and with effective phagolysosomal fusion followed by destruction of Mycobacteria.

Effects of marine beta-1,3 glucan on immune reactions

Glucans have a long history as nonspecific biological modulators. A novel glucan-Phycarine-was isolated from sporophytes of Laminaria digitata. Phycarine showed significant stimulation of phagocytic activity as well as potentiation of synthesis and release of IL-1, IL-6 and TNF-alpha. In addition, Phycarine increased NK cell-mediated killing of tumor cells both in vitro and in vivo while acting via complement receptor type 3 (CR3) receptors.

Lentinan from shiitake mushroom (Lentinus edodes) suppresses expression of cytochrome P450 1A subfamily in the mouse liver

Induction of xenobiotics metabolizing enzymes is related to the formation and chemoprevention of cancer. Since cytochrome P450s (CYPs) including CYP1A subfamily metabolize certain pro-carcinogens to their ultimate forms, down-regulation of CYP1As by food factors leads to the prevention of cancer. Mushroom polysaccharides, especially beta-glucans such as lentinan from Lentinus edodes, possess the anti-tumor and immunomodulating activities through the cytokine production from immunocytes. Recent our studies have demonstrated that lentinan suppresses hepatic CYP1As expression in the both constitutive and inducible levels through the production of tumor necrosis factor-alpha and an increase in the DNA-binding activity of nuclear factor-kappaB. This paper discusses on the effective lentinan dosage and route of administration for suppression of CYP1As.

The β-(1→6)-branched β-(1→3) glucohexaose and its analogues containing an α-(1→3)-linked bond have similar stimulatory effects on the mouse spleen as Lentinan

The stimulatory effects of the synthetic beta-(1-->6)-branched beta-(1-->3) glucohexaose and its analogues containing an alpha-(1-->3)-linked bond on the mouse spleen were studied for elucidation of the mechanism of their antitumor activity, and their stimulatory effects were compared with Lentinan. The mouse spleen's weight was increased after the intraperitoneal (i.p.) injection of the oligosaccharides compared with the saline group. In addition, routinely hematoxylin and eosin (HE)-stained spleen sections showed that the injection also changed the spleen's histopathology. RNA samples were isolated from splenocytes of oligosaccharides, Lentinan or saline-injected mice. Reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot showed that the administration of the oligosaccharides or Lentinan enhanced mouse spleen mRNA production of TNF-alpha but not IL-2. The injection also enhanced Concanavalin A (Con A)-induced mouse splenocytes proliferation, but the in vitro administration of the oligosaccharides did not have the proliferation-enhancing effect. Taken together, these results suggest that the synthetic beta-(1-->6)-branched beta-(1-->3) glucohexaose and its analogues containing an alpha-(1-->3)-linked bond have similar stimulatory effects as Lentinan. Additionally, they may exert their antitumor effects through the induction of splenocytes mediated immune responses.

Effects of lentinan on broiler splenocyte proliferation, interleukin-2 production, and signal transduction

Lentinan (LEN) is an intensively studied beta-glucan that has been shown to have immunostimulating and antitumor functions. However, it currently is not used in veterinary practice and animal production. This study was conducted to investigate the impacts of LEN on broiler splenocyte proliferation, interleukin-2 (IL-2) production, and to explore its effects on receptor signal transduction by determining signaling molecules, including nitric oxide (NO), cytosolic-free Ca2+, cytosolic cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP). The results showed that compared to the control all three measured doses, including 40, 80, and 160 microg/mL LEN, increased splenocyte proliferation and IL-2 production (P < 0.05). Lentinan increased splenocyte NO production and cytosolic-free calcium concentration in a dose-dependent manner (P < 0.001). After incubating splenocytes for 20 min, LEN increased intracellular cAMP and cGMP concentrations at a dose of 80 and 160 microg/mL, respectively. However, after incubating the splenocytes for 60 min, LEN had no effect on cytosolic cAMP and cGMP concentration irrespective of the LEN dosage. Those results indicated that LEN had immunostimulatory effects on splenocytes by increasing splenocyte proliferation and IL-2 production and by activating splenocyte receptor signal transduction.

Effects of intraperitoneal and intranasal application of Lentinan on cellular response in rats

Lentinan (Ajinomoto, Japan) was administrated intraperitoneally (i.p.) and intranasally (i.n.) at different doses (1, 5 and 10 mg/kg) to rats. Effectiveness of Lentinan treatment was evaluated by comparative testing of cell activation (establishing the number, glycolytic and acid phosphatase activity, H2O2 production and killing ability against Salmonella enteritidis and Staphylococcus aureus) at two different compartments--peritoneal and broncho-alveolar cavities. The results indicated that Lentinan induced high-grade activation of peritoneal cells (PCs) and especially of broncho-alveolar cells (BACs) with markedly enhanced effector function (killing ability against S. aureus). Generally, Lentinan, known usually with its parenteral routes of application, can be successful to stimulate the host cell response in the respiratory tract by intranasal route of administration.

Inhibition of human colon carcinoma development by lentinan from shiitake mushrooms (Lentinus edodes)

OBJECTIVES

Lentinan was extracted from shiitake mushrooms (Lentinus edodes) via a new cost-effective procedure that resulted in high purity (88%) and yield. Unlike previous reports whereby the lentinan was given parenterally, in this study the emphasis was on the oral administration of lentinan. The goal is to document whether the efficacy of the antitumor property is still expressed through this route of administration.

DESIGN

Initial study on the action of lentinan was conducted using murine lymphoma (K36) cells in a AKR mouse model. Further investigation on the effectiveness of the extracted lentinan was then performed using human colon-carcinoma cell lines in mice. Six established human colon-carcinoma cell lines segregated into three groups of different degrees of differentiation were used in this study. One group was not fed (control) and the second group was prefed with lentinan for 7 days prior to inoculations with the cancer cells. The size of the tumors that developed was rated after 1 month.

RESULTS

Significant regression in tumor formation was observed in prefed mice compared to control (unfed) mice when K36 or human colon-carcinoma cells were used. Significant reductions in the size of the tumors were observed in mice prefed with lentinan. Follow-up investigation proceeded with the use of nude mice (athymic). Lymphocytes extracted from AKR mice prefed with lentinan for 7 days were inoculated into the nude mice. This was then followed by inoculation of the human colon-carcinoma cell lines into these mice. Much smaller tumors were formed in nude mice inoculated with lymphocytes, in contrast to the larger tumor formed in nude mice without lymphocytes inoculation.

CONCLUSION

This study showed that the antitumor property of lentinan was maintained with oral administration. In addition, "primed" lymphocytes, when given passively to immunodeficient mice, were able to retard the development of tumors in these mice.

Suppressive effect of polysaccharides from the edible and medicinal mushrooms, Lentinus edodes and Agaricus blazei, on the expression of cytochrome P450s in mice

To investigate the effects of lentinan from Lentinas edodes and polysaccharides from Agaricus blazei (ABPS) on the expression of cytochrome P450s (CYPs), lentinan (10 mg/kg/day) or ABPS (200 mg/kg/day) was administered to female BALB/c mice four times every other day by intraperitoneal injection. Lentinan and ABPS suppressed both the constitutive and 3-methylcholanthrene-induced CYP1A expression and ethoxyresorufin-O-deethylation activity in the liver.

The skewing to Th1 induced by lentinan is directed through the distinctive cytokine production by macrophages with elevated intracellular glutathione content

In vivo lentinan (LNT)-elicited peritoneal macrophages (Mps) showed the reduced release of prostaglandins (PGs), IL-10 and IL-6, while it endowed Mps with the elevated capability to produce IL-12 and nitric oxide (NO) upon in vitro triggering, due to the elevated intracellular glutathione (GSH) content in Mps. Deprivation of intracellular GSH completely ablated the production of IL-12. Conversely, lipopolysaccharide (LPS) induced peritoneal Mps with the reduced intracellular GSH content and the reciprocal profile of mediator production. Mps with the elevated intracelluar GSH is arbitrarily termed as reductive Mp (RMp) and that with reduced amount as oxidative Mp (OMp). OMp was converted to RMp when GSH was replenished with glutathione monoethylester (GSH-OEt). The IL-2 administration in combination with LNT exerted the synergistic induction of RMp, resulting in synergistic augmentation of IL-12, NO and reduction of IL-6 production. It was also confirmed that CD4+T cells derived of LNT-administered mice showed augmented IFN-gamma and reduced IL-4 production upon in vitro anti-CD3 stimulation. Taken together it is concluded that skewing of Th1/Th2 balance to Th1 by a beta-(1-3)-glucan, LNT, is directed through the distinctive production of IL-12 versus IL-6, IL-10 and prostaglandin E2 (PGE2) by Mps, depending on intracellular GSH redox status. To the efficient tumor immunotherapy, it may be one of the critical elements to induce a reductive form of Mps in tumor stromal tissues to maintain Th1 response.

Systemic administration of lentinan, a branched beta-glucan, enhances long-term potentiation in the rat dentate gyrus in vivo

We investigated the effects of oral and intravenous application of lentinan, a branched beta-glucan, on the induction of long-term potentiation (LTP) in the rat dentate gyrus in vivo. Oral administration of lentinan (200 mg/kg) enhanced the induction of LTP evoked by sub-threshold tetanic stimulation (20 pulses at 60 Hz) of the perforant pathway without affecting normal synaptic potentials. Intravenous injection of the compound (0.2-10.0 mg/kg) also enhanced the induction of LTP in a bell-shaped manner, whereas it had no effect on LTP evoked by supra-threshold tetanic stimulation (100 pulses at 100 Hz). Structurally related beta-glucans did not mimic the lentinan-triggered enhancement of LTP. These results suggest that peripherally applied lentinan facilitates the synaptic efficacy of the dentate gyrus neurons in vivo.