Zymosan attenuates melanoma growth progression, increases splenocyte proliferation and induces TLR-2/4 and TNF-α expression in mice

Immunization with a low dose of zymosan A confers resistance to depression-like behavior and neuroinflammatory responses in chronically stressed mice

Stimulation of the innate immune system prior to stress exposure is a possible strategy to prevent depression under stressful conditions. Based on the innate immune system stimulating activities of zymosan A, we hypothesize that zymosan A may prevent the development of chronic stress-induced depression-like behavior. Our results showed that a single injection of zymosan A 1 day before stress exposure at a dose of 2 or 4 mg/kg, but not at a dose of 1 mg/kg, prevented the development of depression-like behaviors in mice treated with chronic social defeat stress (CSDS). The prophylactic effect of a single zymosan A injection (2 mg/kg) on CSDS-induced depression-like behaviors disappeared when the time interval between zymosan A and stress exposure was extended from 1 day or 5 days to 10 days, which was rescued by a second zymosan A injection 10 days after the first zymosan A injection and 4 days (4×, once daily) of zymosan A injections 10 days before stress exposure. Further analysis showed that a single zymosan A injection (2 mg/kg) 1 day before stress exposure could prevent the CSDS-induced increase in pro-inflammatory cytokines in the hippocampus and prefrontal cortex. Inhibition of the innate immune system by pretreatment with minocycline (40 mg/kg) abolished the preventive effect of zymosan A on CSDS-induced depression-like behaviors and CSDS-induced increase in pro-inflammatory cytokines in the brain. These results suggest that activation of the innate immune system triggered by zymosan A prevents the depression-like behaviors and neuroinflammatory responses in the brain induced by chronic stress.

Doxorubicin-loaded zymosan nanoparticles: Synergistic cytotoxicity and modulation of apoptosis and Wnt/β-catenin signaling pathway in C26 colorectal cancer cells

Zymosan is a β-glucan isolated from Saccharomyces cerevisiae that could be employed for drug delivery. We synthesized zymosan nanoparticles and measured their structural and morphological properties using XRD, UV-Vis spectroscopy, TEM and AFM. The loading of doxorubicin (DOX) onto the nanoparticles was confirmed by FT-IR, and the DOX release was shown to be pH-dependent. The effect of these agents on C26 cell viability was evaluated by MTT tests and the expression of genes connected with the Wnt/β-catenin pathway and apoptosis were analyzed by RT-qPCR and Western blotting. Treatments were able to suppress the proliferation of C26 cells, and the zymosan nanocarriers loaded with DOX enhanced the anti-proliferative effect of DOX in a synergistic manner. Zymosan nanoparticles were able to suppress the expression of cyclin D1, VEGF, ZEB1, and Twist mRNAs. Treatment groups upregulated the expression of caspase-8, while reducing the Bax/Bcl-2 ratio, thus promoting apoptosis. In conclusion, zymosan nanoparticles as DOX nanocarriers could provide a more targeted drug delivery through pH-responsiveness, and showed synergistic cytotoxicity by modifying Wnt/β-catenin signaling and apoptosis.

Zymosan A Improved Doxorubicin-Induced Ventricular Remodeling by Evoking Heightened Cardiac Inflammatory Responses and Healing in Mice

Background Doxorubicin-induced myocardial injury is reflected by the presence of vacuolization in both clinical and animal models. The lack of scar tissue to replace the vacuolizated cardiomyocytes indicates that insufficient cardiac inflammation and healing occurred following doxorubicin injection. Whether improved macrophage activity by zymosan A (zymosan) ameliorates doxorubicin-induced ventricular remodeling in mice is unknown. Methods and Results Mice were intravenously injected with vehicle or doxorubicin (5 mg/kg per week, 4 weeks), and cardiac structure and function were assessed by echocardiography. Two distinct macrophage subsets in hearts following doxorubicin injection were measured at different time points by flow cytometry. Moreover, cardiomyocyte vacuolization, capillary density, collagen content, and ventricular tensile strength were assessed. The therapeutic effect of zymosan (3 mg/kg, single injection) on doxorubicin-induced changes in the aforementioned parameters was determined. At the cellular level, the polarization of monocytes to proinflammatory or reparative macrophages were measured, with or without doxorubicin (0.25 and 0.5 μmol/L). Doxorubicin led to less proinflammatory and reparative macrophage infiltration in the heart in the early phase, with decreased cardiac capillary density and collagen III in the chronic phase. In cell culture, doxorubicin (0.5 μmol/L) repressed macrophage transition toward both proinflammatory and reparative subset. Zymosan enhanced both proinflammatory and reparative macrophage infiltration in doxorubicin-injected hearts, evoking a heightened acute inflammatory response. Zymosan alleviated doxorubicin-induced cardiomyocyte vacuolization in the chronic phase, in parallel with enhanced collagen content, capillary density, and ventricular tensile strength. Conclusions Zymosan improved cardiac healing and ameliorated doxorubicin-induced ventricular remodeling and dysfunction by activating macrophages at an optimal time.

Plants against cancer: the immune-boosting herbal microbiome: not of the plant, but in the plant. Basic concepts, introduction, and future resource for vaccine adjuvant discovery

The presence of microorganism communities (MOCs) comprised of bacteria, fungi, archaea, algae, protozoa, viruses, and the like, are ubiquitous in all living tissue, including plant and animal. MOCs play a significant role in establishing innate and acquired immunity, thereby influencing susceptibility and resistance to disease. This understanding has fostered substantial advancements in several fields such as agriculture, food science/safety, and the development of vaccines/adjuvants, which rely on administering inactivated-attenuated MOC pathogens. Historical evidence dating back to the 1800s, including reports by Drs Busch, Coley, and Fehleisen, suggested that acute febrile infection in response to "specific microbes" could trigger spontaneous tumor remission in humans. This discovery led to the purposeful administration of the same attenuated strains, known as "Coley's toxin," marking the onset of the first microbial (pathogen) associated molecular pattern (MAMPs or PAMPs)-based tumor immunotherapy, used clinically for over four decades. Today, these same MAMPS are consumed orally by billions of consumers around the globe, through "specific" mediums (immune boosting "herbal supplements") as carriers of highly concentrated MOCs accrued in roots, barks, hulls, sea algae, and seeds. The American Herbal Products Association (AHPA) mandates microbial reduction in botanical product processing but does not necessitate the removal of dead MAMP laden microbial debris, which we ingest. Moreover, while existing research has focused on the immune-modulating role of plant phytochemicals, the actual immune-boosting properties might instead reside solely in the plant's MOC MAMP laden biomass. This assertion is logical, considering that antigenic immune-provoking epitopes, not phytochemicals, are known to stimulate immune response. This review explores a neglected area of research regarding the immune-boosting effects of the herbal microbiome - a presence which is indirectly corroborated by various peripheral fields of study and poses a fundamental question: Given that food safety focuses on the elimination of harmful pathogens and crop science acknowledges the existence of plant microbiomes, what precisely are the immune effects of ingesting MAMPs of diverse structural composition and concentration, and where are these distributed in our botanicals? We will discuss the topic of concentrated edible MAMPs as acid and thermally stable motifs found in specific herbs and how these would activate cognate pattern recognition receptors (PPRs) in the upper gut-associated lymphoid tissue (GALT), including Peyer's patches and the lamina propria, to boost antibody titers, CD8+ and CD4+ T cells, NK activity, hematopoiesis, and facilitating M2 to M1 macrophage phenotype transition in a similar manner as vaccines. This new knowledge could pave the way for developing bioreactor-grown/heat-inactivated MOC therapies to boost human immunity against infections and improve tumor surveillance.

In Vivo Zymosan Treatment Induces IL15-Secreting Macrophages and KLRG1-Expressing NK Cells in Mice

Beta-glucan (β-glucan) is a natural polysaccharide produced by fungi, bacteria, and plants. Although it has been reported that β-glucan enhances innate immune memory responses, it is unclear whether different types of β-glucans display similar immune effects. To address this issue, we employed zymosan (β-1,3-glycosidic linkage) and pustulan (β-1,6-glycosidic linkage) to investigate their in vivo effects on innate memory immune responses. We examined the changes of innate memory-related markers in macrophages and natural killer (NK) cells, two immune cell types that display innate memory characteristics, at two different time points (16 h and 7 days) after β-glucan stimulation. We found that short-term (16 h) zymosan treatment significantly induced macrophages to upregulate IL15 production and increased surface IL15Rα expression on NK cells. In addition, long-term (7 days) zymosan treatment significantly induced macrophages to upregulate the expression of innate memory-related markers (e.g., TNFα, HIF1α, and mTOR) and induced NK cells to express enhanced levels of KLRG1, known as an innate memory-like marker. Our results provide support that zymosan can be an effective adjuvant to promote innate memory immune responses, providing a bridge between innate and adaptive immune cells to enhance various immune responses such as those directed against tumors.

Toll-Like Receptor 4 Exacerbates Mycoplasma pneumoniaevia Promoting Transcription Factor EB-Mediated Autophagy

Mycoplasma pneumoniae (M. pneumoniae) is the most common cause of community-acquired pneumonia. Toll-like receptors (TLRs) play an essential role in pneumonia. The purpose of this study was to investigate the roles of TLR4 in M. pneumoniae. Mice were administrated with 100 μl (1 × 107 ccu/ml) of M. pneumoniae. HE staining was applied for histological analysis. The protein expression was determined by western blot. The cytokine level was detected by ELISA. The results showed that TLR4-deficient mice were protected from M. pneumoniae. However, downregulation of TLR4 inhibited inflammatory response and autophagy. Moreover, transcription factor EB (TFEB) participated in M. pneumoniae-induced inflammatory response and autophagy, while knockdown of TLR4 downregulated TFEB and its nuclear translocation.

PD-L1 and ICOSL discriminate human Secretory and Helper dendritic cells in cancer, allergy and autoimmunity

Dendritic cells (DC) are traditionally classified according to their ontogeny and their ability to induce T cell response to antigens, however, the phenotypic and functional state of these cells in cancer does not necessarily align to the conventional categories. Here we show, by using 16 different stimuli in vitro that activated DCs in human blood are phenotypically and functionally dichotomous, and pure cultures of type 2 conventional dendritic cells acquire these states (termed Secretory and Helper) upon appropriate stimuli. PD-L1highICOSLlow Secretory DCs produce large amounts of inflammatory cytokines and chemokines but induce very low levels of T helper (Th) cytokines following co-culturing with T cells. Conversely, PD-L1lowICOSLhigh Helper DCs produce low levels of secreted factors but induce high levels and a broad range of Th cytokines. Secretory DCs bear a single-cell transcriptomic signature indicative of mature migratory LAMP3+ DCs associated with cancer and inflammation. Secretory DCs are linked to good prognosis in head and neck squamous cell carcinoma, and to response to checkpoint blockade in Melanoma. Hence, the functional dichotomy of DCs we describe has both fundamental and translational implications in inflammation and immunotherapy.

Phenotypic and functional states of dendritic cells critically influence the outcome of cancer and inflammation. Authors here show by single cell transcriptomics and in vitro validation assays that dichotomous PD-L1 and ICOSL expression assign dendritic cells to secretory and helper functions, with respective predominance of inflammatory cytokine expression or T helper cytokine induction.

Structural specificities of cell surface β-glucan polysaccharides determine commensal yeast mediated immuno-modulatory activities

Yeast is an integral part of mammalian microbiome, and like commensal bacteria, has the potential of being harnessed to influence immunity in clinical settings. However, functional specificities of yeast-derived immunoregulatory molecules remain elusive. Here we find that while under steady state, β-1,3-glucan-containing polysaccharides potentiate pro-inflammatory properties, a relatively less abundant class of cell surface polysaccharides, dubbed mannan/β-1,6-glucan-containing polysaccharides (MGCP), is capable of exerting potent anti-inflammatory effects to the immune system. MGCP, in contrast to previously identified microbial cell surface polysaccharides, through a Dectin1-Cox2 signaling axis in dendritic cells, facilitates regulatory T (Treg) cell induction from naïve T cells. Furthermore, through a TLR2-dependent mechanism, it restrains Th1 differentiation of effector T cells by suppressing IFN-γ expression. As a result, administration of MGCP display robust suppressive capacity towards experimental inflammatory disease models of colitis and experimental autoimmune encephalomyelitis (EAE) in mice, thereby highlighting its potential therapeutic utility against clinically relevant autoimmune diseases.

Preliminary study of the toxicity and radioprotective effects of zymosan in vitro and in vivo

BACKGROUND

This study aimed to confirm the cytotoxicity of zymosan in vitro and in vivo and determine the appropriate treatment time and the dose of zymosan.

METHODS

AHH-1 cells and HIECs were administered by 0, 20, 40, 80 or 160 μg/mL zymosan. The CCK-8 assay and flow cytometry were used to evaluate the cell viability and apoptosis 24 h, 48 h, and 72 h after administration. Furthermore, 12 h before irradiation, the cells were treated with 0, 5, 10, or 20 μg/mL zymosan and then irradiated with 4 Gy X-rays. Cell viability and apoptosis were measured by the CCK-8 assay and flow cytometry at 24 h. In addition, the protective effect of zymosan against radiation in vitro was compared to that of 20 μg/mL LPS. In vivo, weight, the spleen index, and the thymus index were measured to evaluate the toxicity of 0, 5, 10, 20, and 10 mg/kg zymosan. In addition, rats were treated with 0, 2, 4, 8, or 10 mg/kg zymosan and then irradiated with 7 Gy X-rays. The survival rate, organ index were evaluated. The protective effect of zymosan against radiation in vivo was compared to that of 10 mg/kg LPS a positive control.

RESULTS

The viability and apoptosis of cells treated with different doses and treatment times of zymosan were not different from those of control cells (p < 0.05). Furthermore, cell viability and apoptosis were clearly improved after zymosan preadministration (p < 0.05). The radioprotective effect of zymosan was dose-dependent. In addition, the viability of cells pretreated with zymosan was higher than that of cells pretreated with LPS, and the apoptosis rate of zymosan-treated cells was lower than that of cells pretreated with LPS (p < 0.05). In vivo, weight, the spleen index and the thymus index were significantly decreased by zymosan at a concentration of 20 mg/kg (p < 0.05). Further experiments showed that the concentration at which zymosan exerted radioprotective effects was 10 mg/kg. The survival curves in the irradiated rats were barely separated between the LPS treatment and zymosan treatment.

CONCLUSION

Zymosan administration before radiation exposure significantly increased cell viability and the survival rates of rats.

Toll-like receptor-mediated innate immunity against herpesviridae infection: a current perspective on viral infection signaling pathways

Background

In the past decades, researchers have demonstrated the critical role of Toll-like receptors (TLRs) in the innate immune system. They recognize viral components and trigger immune signal cascades to subsequently promote the activation of the immune system.

Main body

Herpesviridae family members trigger TLRs to elicit cytokines in the process of infection to activate antiviral innate immune responses in host cells. This review aims to clarify the role of TLRs in the innate immunity defense against herpesviridae, and systematically describes the processes of TLR actions and herpesviridae recognition as well as the signal transduction pathways involved.

Conclusions

Future studies of the interactions between TLRs and herpesviridae infections, especially the subsequent signaling pathways, will not only contribute to the planning of effective antiviral therapies but also provide new molecular targets for the development of antiviral drugs.

Different activities of antitumor immunomodulators to induce neutrophil adherence response

Functions of neutrophils, major participant in host defense mechanisms, are known to be regulated by various types of immunomodulators. Capacity of immunomodulators which are reported to show antitumor effect in vivo to induce neutorophil adherence response in vitro was investigated. Several bacterial immunomodulators (OK-432, Corynebacterium parvum, B.C.G.) and components of bacteria cell walls (lipopolysaccharide (LPS), lipid A, lipoteicoic acid, N-cell wall skelton (N-CWS), muramyl dipeptide (MDP)) and fungal polysaccharides (lentinan, zymosan A, etc.) were tested. Neutrophils prepared from peripheral blood of healthy men were incubated with each immunomodulator at 37°C for 60 min in 96 well plastic plates, then neutrophils adherent to substratum were stained by crystal violet and their optical density at 570 nm was measured as a parameter of neutrophil adherence. Although purified polysaccharides mainly prepared from fungi did not induce the adherent response, not only bacterial bodies and their components but also tumor necrosis factor-α (TNF-α) clearly induced it. On the base of these results, functional classification and typing of immunomodulators by different activities in neutrophil adherence was discussed.

Fungal polysaccharides

Fungal bioactive polysaccharides are well known and have been widely used in Asia as a part of the traditional diet and medicine. In fact, some biopolymers (mainly β-glucans or glycoconjugate) have already made their way to the market as antitumor or immunostimulating drugs. In the last decades, the relationship between structure and activity of polysaccharides and their detailed mode of action have been the core of intense research to understand and utilize their medicinal properties. Most of the antitumor polysaccharides belong to conserved β-glucans, with a linear β-(1→3)-glucan backbone and attached β-(1→6) branch. Structurally different β-glucans appear to have different affinities toward their receptors and thus generate markedly different host responses. However, their antitumor activities are mainly influenced by molecular mass, degree of branching, conformation, and structure modification of the polysaccharides. β-Glucans act on several immune receptors including Dectin-1, complement receptor (CR3) and TLR-2/6, then trigger both innate and adaptive response and enhance opsonic and nonopsonic phagocytosis. Various receptor interactions explain the possible mode of actions of polysaccharides.

Evaluation of phage therapy in the treatment of Staphylococcus aureus-induced mastitis in mice

Mastitis in dairy cows is generally considered to be the most expensive disease for dairy farmers worldwide. The overuse of antibiotics is a major problem in the treatment of bovine mastitis, and bacteriophage therapy is expected to provide an alternative treatment. The primary aim of this study was to evaluate the efficacy of a phage cocktail against mastitis in a mouse model. First, a Staphylococcus aureus strain was isolated from milk samples taken from mastitis cows from dairy farms in Xinjiang, China, and it was designated as Sau-XJ-21. Next, two phages (designated as vBSM-A1 and vBSP-A2) with strong lytic activity against Sau-XJ-21 were isolated from mixed sewage samples collected from three cattle farms in Xinjiang. Phages vBSM-A1 and vBSP-A2 were identified as members of the Myoviridae and Podoviridae families, respectively. The two phages exhibited a wide range of hosts, especially phage vBSM-A1. To evaluate the effectiveness of the two phages in the treatment against mastitis, female lactating mice were used 10-14 days after giving births. The mice were divided into six groups; one group was kept as healthy control, while the remaining five groups were inoculated with the isolated S. aureus strain to induce mastitis. Four hours after bacterial inoculation, mice in these groups were injected with 25 μL phosphate buffer saline (negative control), ceftiofur sodium (positive control), or phage, either individually or as a cocktail. The mice were sacrificed 20 h later, and the mammary glands were removed and subjected to further analysis, including the quantitation of colony-forming units (CFU), plaque-forming units (PFU), and gross macroscopic as well as histopathology observation. Mice with induced mastitis exhibited significantly improved mastitic pathology and decreased bacterial counts after they had been given phage treatments, with the phage cocktail being more superior than either phage alone. Furthermore, the cocktail treatment also maintained the highest intramammary phage titer without spreading systemically. The effectiveness of the phage cocktail was comparable to that produced by ceftiofur sodium. According to the data obtained for the mouse model of mastitis, phage therapy could be considered as an innovative alternative to antibiotics for the treatment of bovine mastitis.

Tackling molecular targets beyond PD-1/PD-L1: Novel approaches to boost patients' response to cancer immunotherapy

In the new era of immunotherapy, which has changed the clinical oncology practice guidelines, there is a pressing need for finding novel approaches to tune up the clinical outcomes of immunotherapy and extend its benefits to a wider cohort of cancer patients. Several non-classical molecular immune targets beyond PD-1/PD-L1 signaling were shown to be engaged as feedback resistance circuits to shut down the antitumor immune response mediated by the classical immune checkpoint inhibitors. Those include T-cell inducible co-stimulator (ICOS), CD40, CD47, V-domain Ig suppressor of T-cell activation (VISTA), cyclin-dependent kinase (CDK)12, enhancer of Zeste homolog 2 (EZH2), toll-like receptors (TLRs) and OX-40 (CD134). Herein we critically discussed the latest studies concerned with understanding the mechanisms involved in the negative clinical response to classical immunotherapies and strategies to optimize the efficacy of cancer immunotherapy through novel combinatorial approaches.

Protective effects of zymosan on heat stress-induced immunosuppression and apoptosis in dairy cows and peripheral blood mononuclear cells

Dairy cows exposed to heat stress (HS) show decreased performance and immunity, but increased heat shock protein expressions and apoptosis. Zymosan, an extract from yeast cell walls, has been shown to modulate immune responses and defense against oxidative stress. However, few literatures are available about the effects of zymosan on immune responses and other parameters of the dairy cows under HS. Here, both primary peripheral blood mononuclear cell (PBMC) and dairy cow models were established to assess the effects of zymosan on performance, immunity, heat shock protein, and apoptosis-related gene expressions of dairy cows under HS. In vitro study showed that proliferation, IL-2 production, and Bcl-2/Bax-α ratio of cow primary PBMC were reduced, whereas hsp70 mRNA and protein expressions, as well as Annexin V-bing, were increased when PBMCs were exposed to heat. In contrast, zymosan significantly reversed these above changes induced by the HS. In the in vivo study, 40 Holstein dairy cows were randomly selected and assigned into zymosan group (supplemental zymosan; n = 20) and control group (no supplemental zymosan; n = 20). The results showed that zymosan improved significantly the dry matter intake and milk yield, increased IgA, IL-2, and tumor necrosis factor-α (TNF-α) contents in sera, as well as hepatic Bcl-2/Bax-α ratio, but decreased respiration rate and hepatic hsp70 expressions in the dairy cows under HS. Taken together, zymosan could alleviate HS-induced immunosuppression and apoptosis and improve significantly the productive performance and immunity of dairy cows under HS.