ß-Glucan-A promising immunocyte-targeting drug delivery vehicle: Superiority, applications and future prospects.

Drug delivery technologies that could convert promising therapeutics into successful therapies have been under broad research for many years. Recently, ß-glucans, natural-occurring polysaccharides extracted from many organism species such as yeast, fungi and bacteria, have attracted increasing attention to serve as drug delivery carriers. With their unique structure and innate immunocompetence, ß-glucans are considered as promising carriers for targeting delivery especially when applied in the vaccine construction and oral administration of therapeutic agents. In this review, we focus on three types of ß-glucans applied in the drug delivery system including yeast ß-glucan, Schizophyllan and curdlan, highlighting the benefits of ß-glucan based delivery system. We summarize how ß-glucans as delivery vehicles have aided various therapeutics ranging from macromolecules including proteins, peptides and nucleic acids to small molecular drugs to reach desired cells or organs in terms of loading strategies. We also outline the challenges and future directions for developing the next generation of ß-glucan based delivery systems.

Schizophyllan from Schizophyllum commune BRM 060008: Potential application as an inhibitor of lipase.

ß-D-glucan has significant implications in regulating lipid metabolism and preventing diseases associated with lipid accumulation. Schizophyllan (SPG) from Schizophyllum commune fungus is a commercially important ß-glucan with applications in the health food industry, pharmacy, and cosmetics. However, SPG was obtained by submerged culture of the wood-rotting and filamentous fungus S. commune BRM 060008, which may have been isolated from the Cerrado Biome of Brazil. In this study, to confirm that the polysaccharide produced by BRM 060008 strain fermentation was indeed (1→3)(1→6)-ß-D-glucan, it was purified and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, high-performance size exclusion chromatography, nuclear magnetic resonance, and methylation analysis. The polysaccharide produced was identified as the ß-D-glucan expected with a high molecular weight (1.093 × 106 g/mol) and the thermogravimetric analysis indicated a maximum degradation temperature of ~324 °C and a 60 % residual weight, lower than commercial SPG. The molecular structure and thermal properties of the ß-D-glucan were similar to the commercial sample. Additionally, the in vitro pancreatic lipase inhibitory activity was evaluated, investigating anti-obesity and anti-lipidemic properties. The results showed unprecedented lipase inhibition activity to SPG prepared using the S. commune strain BRM 060008, making it promising for food and pharmaceutical applications.

Unlocking the benefits of split gill mushroom: Chemical analysis and prebiotic properties of schizophyllan extract.

The edible split gill mushroom is considered both a nutritive and therapeutic superfood, as well as rich in schizophyllan and protein. Prebiotic properties and other biological effects distinguish the schizophyllan (ß-glucan). Thus, this research investigates the identity of the mushroom strain, the nutritional composition of this mushroom, and the schizophyllan extract for further analysis, including its prebiotic activity and so on. The experimental results revealed that this mushroom was identified as Schizophyllum commune, comprising more excellent carbohydrates, protein, crude fiber, lower fat, and no heavy metal detection. Moreover, this extract consisted of pharmaceutical hydrophobin (14.0-18.5 kDa), lectin protein (21-35 kDa), bioactive purpurin or red pigment, including the prebiotic ß-glucan stimulating the proliferation of probiotic bacteria isolated from yogurt. Therefore, both S. commune and the schizophyllan extract can be used as a prebiotic candidate, functional food, and nutraceutical product.

Association with Imidazole in the Cooperative Order-Disorder Transition in Aqueous Solution of Schizophyllan.

Schizophyllan, a triple helical polysaccharide, exhibits cooperative order-disorder transition (CODT) in aqueous solutions. The transition transforms the ordered structure (triple helix I) formed between the branched side chains and solvent molecules into the disordered structure (triple helix II) without dissociation of the triple helix. The CODT behaviors in H2O-imidazole mixtures containing HCl with different molar ratios of imidazole/HCl were investigated by adiabatic calorimetry and differential scanning calorimetry on two schizophyllan solutions with different molar masses. The transition temperature (Tr) and the transition enthalpy (ΔHr) significantly depended on both of the mole fractions of imidazole and imidazole/HCl. The composition dependences of Tr and ΔHr in H2O-imidazole mixtures were analyzed with linear cooperative transition theory for the solvent-stabilizing effect in the mixture with active compounds. Theoretical analyses confirmed that both imidazole and imidazolium ions in the solutions competitively interact with the side chain of the triple helix.

Efficacy of SPG-ODN 1826 Nanovehicles in Inducing M1 Phenotype through TLR-9 Activation in Murine Alveolar J774A.1 Cells: Plausible Nano-Immunotherapy for Lung Carcinoma.

Alveolar macrophages are the first line of defense against intruding pathogens and play a critical role in cancer immunology. The Toll-like receptor (TLR) family mediates an important role in recognizing and mounting an immune response against intruding microbes. TLR-9 is a member of the intracellular TLR family, which recognizes unmethylated CG motifs from the prokaryotic genome. Upon its activation, TLR-9 triggers downstream of the MyD-88-dependent transcriptional activation of NF-κB, and subsequently results in abundant inflammatory cytokines expression that induces a profound inflammatory milieu. The present exploratory investigation aimed at elucidating the potency of schizophyllan for entrapping ODN 1826 (SPG-ODN 1826)-mediated stimulation of TLR-9 in provoking an inflammatory-type response in murine alveolar macrophages. Schizophyllan (SPG), a representative of the ß-glucan family, was used in the present study as a nanovehicle for endosomal trafficking of CpG ODN 1826. TEM analysis of SPG-ODN 1826 nanovehicles revealed that the prepared nanovehicles are spherical and have an average size of about 100 nm. Interestingly, SPG-ODN 1826 nanovehicles were competent in delivering their therapeutic payload within endosomes of murine alveolar macrophage (J774A.1) cells. Exposure of these nanovehicles within LPS stimulated J774A.1, resulted in a significant provocation of reactive oxygen species (ROS) (p < 0.01) in comparison to CpG ODN 1826 alone. Moreover, the formulated nanovehicles succeeded in generating a profound Th1-based cytokine profile constituted by enhanced expression of IFN-γ (p < 0.001) and IL-1ß (p < 0.001) inflammatory cytokines. These findings clearly indicated the immunostimulatory potential of SPG-ODN 1826 nanovehicles for inducing the Th1-type phenotype, which would certainly assist in skewing M2 phenotype into the much-desired M1 type during lung cancer.

Modular formation of hyaluronic acid/ß-glucan hybrid nanogels for topical dermal delivery targeting skin dendritic cells.

Transdermal immunomodulation is of increasing interest as an efficient drug delivery method. It non-invasively delivers drugs directly to skin-resident immune cells, thereby avoiding the first-pass metabolism. Herein, we prepared ovalbumin-conjugated hyaluronic acid-methacrylate (HAMA-OVA) and schizophyllan-methacrylate (SPGMA) hybrid nanogels and investigated their suitability for topical delivery. The particle size was controlled to between 100 and 300 nm using ultrasonication and filtering processes. The nanogels penetrated the porcine stratum corneum layer and were deposited in the dermis via hybridization with HAMA. In addition, the hybridized SPGMA promoted the internalization of the nanogels into dendritic cells (DCs; JAWSII), which resulted in an improvement in the ovalbumin delivery efficiency. In molecular biological assessments, the hybrid nanogels upregulated the DC activation marker interleukin-6 and induced DC maturation, indicating antigen-presenting behavior. These results suggest that HAMA/SPGMA hybrid nanogels are a promising topical delivery carrier for immunomodulation and vaccinations.

Leishmanial CpG DNA nanovesicles: A propitious prophylactic approach against visceral leishmaniasis.

Unmethylated CpG motifs with phosphothioate backbone trigger TLR9 to elicit innate immune response characterized by the production of Th1 cytokines. The use of CpG DNA as an adjuvant has established its role in potentiating the humoral and cell mediated vaccine specific immune response. However, none of the synthetic oligodeoxynucleotides (ODNs) know and used till date are associated with the parasite itself. Our group identified a novel CG rich sequence of 14 base pairs from Leishmania donovani genome (Ld CpG ODN) and established it as a TLR9 agonist. The present study was designed to ascertain the adjuvanticity of Ld CpG ODN with soluble leishmanial antigen in experimental model of L. donovani. During the study Schizophyllan (SPG), a fungal polymer was used for encapsulating Ld CpG ODN for efficient endosomal delivery. The synthesized nanovehicles were of nearly 100 nm and localized within endosomes as confirmed by confocal microscopy. Immunization studies displayed the superior ability of synthesized nanovehicles co-administered with parasite antigen in augmenting innate immune response in comparison to ODN, nanoparticles or soluble antigen alone. The response included generation of ROS, NO and iNOS expression followed by proinflammatory cytokine milieu with reduced parasitic load within liver, spleen and bone marrow. These immune-tailored particles in combination with parasitic antigens elicited significant generation of cell mediated response owing to the presence of high levels of CD8+ T-cells and lymphocyte proliferation. Moreover, vaccination regime with synthesized adjuvant also activated humoral immunity by escalating the levels of IgG2 followed by reduced levels of anti-leishmanial IgG and IgG1 antibodies. The findings support the efficacy of Ld CpG ODN as a potential adjuvant against visceral leishmaniasis.

Induction of potent cell growth inhibition by schizophyllan/K-ras antisense complex in combination with gemcitabine.

Antisense oligonucleotides (AS-ODNs) specifically hybridize with target mRNAs, resulting in interference with the splicing mechanism or the regulation of protein translation. In our previous reports, we demonstrated that ß-glucan schizophyllan (SPG) can form a complex with AS-ODNs attached with oligo deoxyadenosine dA40 (AS-ODN-dA40/SPG), and that this complex can be recognized by ß-glucan receptor Dectin-1 on antigen presenting cells and lung cancer cells. In many types of cancer cell, activating K-ras mutations related to malignancy are frequently observed. In this study, we first designed 78 AS-ODNs for K-ras to optimize the sequence for highly efficient gene suppression. The selected AS-ODN (K-AS07) having dA40 made a complex with SPG. The resultant complex (K-AS07-dA40/SPG) showed an effect of silencing the ras gene in the cells (PC9: human adenocarcinoma differentiated from lung tissue) expressing Dectin-1, leading to the suppression of cell growth. Furthermore, the cytotoxic effect was enhanced when used in combination with the anticancer drug gemcitabine. Gemcitabine, a derivative of cytidine, was shown to interact with dA40 in a sequence-dependent manner. This interaction did not appear to be so strong, with the gemcitabine being released from the complex after internalization into the cells. SPG and the dA40 part of K-AS07-dA40 play roles in carriers for K-AS07 and gemcitabine, respectively, resulting in a strong cytotoxic effect. This combination effect is a novel feature of the AS-ODN-dA40/SPG complexes. These results could facilitate the clinical application of these complexes for cancer treatment.

Adsorption of enhanced oil recovery polymer, schizophyllan, over carbonate minerals.

Schizophyllan is a natural polysaccharide that has shown great potential as enhanced oil recovery (EOR) polymer for high-temperature, high-salinity reservoirs. Nevertheless, the adsorption behavior of schizophyllan over carbonate minerals remains ambiguous element towards its EOR applications. Here, we investigate the adsorption of schizophyllan on different carbonate minerals. The effect of mineral type, salinity, and background ions on adsorption is analyzed. Our results indicate the adsorption capacity is higher on calcite and dolomite compared to silica and kaolin and the adsorption capacity decreases with salinity. Moreover, the adsorption kinetics follows pseudo-second order mechanism regardless of the mineral type. Adsorption over calcite is diminished in presence of water structure making ions and enhanced in presence of structure breaking ion and in presence of urea. Gel permeation chromatography results reveal the preferential adsorption of longer chains. The adsorption over carbonate minerals proceed via complex formation between polymer molecule and mineral surface.

Inflammatory responses of macrophage-like RAW264.7 cells in a 3D hydrogel matrix to ultrasonicated schizophyllan.

The water-soluble ß-glucan schizophyllan has diverse immunomodulatory activities. However, its biological activities have only been explored using cells grown in two-dimensional (2D) culture condition, which does not replicate the three-dimensional (3D) microenvironment of actual tissue, resulting in mismatches between in vitro and in vivo findings. In this study, we investigated the immunomodulatory effects of ultrasonicated schizophyllan (uSPG) on RAW264.7 cells encapsulated in 3D poly(ethylene glycol) hydrogel. Cells grown in 3D were less sensitive to uSPG than those grown in 2D, although uSPG upregulated M1 macrophage phenotype markers in both conditions. This might be due to the low availability of uSPG recognition receptors of cells grown in 3D. Conversely, uSPG promoted gene expressions of M2 macrophage phenotype markers in 3D, suggesting uSPG-induced immune-regulation of macrophages in real tissues. These findings imply that the immunomodulatory effects of uSPG on macrophages should be carefully interpreted in terms of the microenvironment.

A novel double-network antibacterial hydrogel based on aminated bacterial cellulose and schizophyllan.

In this study, a novel hydrogel composed of bacterial cellulose (BC) and schizophyllan (SPG) biopolymers with improved mechanical, swelling and antibacterial properties was developed. BC was firstly functionalized using 3-aminopropyl triethoxysilane (APTES) to provide better interaction with SPG. A diffraction peak at 5.7° in the XRD pattern of amine-grafted BC/SPG membrane revealed the intercalation of SPG into BC network. SEM images of amine-grafted BC/SPG showed that the fibrillar network of BC was totally covered with schizophyllan. Two distinct stages of weight loss in TGA thermo-gram of amine grafted BC/SPG verified the successful entrance of SPG into BC fibrils. Tensile strength of the amine-grafted BC/SPG considerably increased to 42.19 ±â€¯7.16 MPa as compared to neat BC (4.41 ± 0.38 MPa) and amine-grafted BC (7.90 ±â€¯0.71 MPa). It also showed the highest swelling degree (800 ±â€¯80%). Amine-grafted BC/SPG exhibited moderate antibacterial activity. MTT assay showed that amine-grafted BC/SPG stimulated the proliferation of normal human fibroblast cells.

A comparative study on schizophyllan and chitin nanoparticles for ellagic acid delivery in treating breast cancer.

In this study, following encapsulation of ellagic acid (EA), an anti-cancer agent, loaded in schizophyllan (EA/SPG-NP) and chitin (EA/Ch-NP) nanoparticles, its release in 95% ethanol, and different mediums of digestive systems with pH ranging 1.5 to 7.4, were examined before investigating for treatment of breast cancer MCF-7cells. Following synthesis, the EA was characterized by FT-IR, SEM, XRD, DLS and zeta potential analysis. Loading capacity of schizophyllan and chitin were 30.08 and 79.52%, respectively, while SEM images indicated respective size distributions of 217.8 and 39.82 nm, with the corresponding zeta potentials being +27 and -9.14 mV. As EA was loaded in nanoparticles, antioxidant activity, examined by DPPH method, of the free EA was found to be higher than both EA/SPG-NP and EA/Ch-NP, but lower than the latter at 7.4 pH. Interestingly, scavenging activities for EA and EA/SPG-NP reduced for higher pH. The MTT cytotoxicity indicated that EA/SPG-NP and EA/Ch-NP inhibited effectively cell growth of breast cancer cell lines at IC50 of 60 and 115 µg/ml, respectively.

Conformation and cooperative order-disorder transition in aqueous solutions of ß-1,3-d-glucan with different degree of branching varied by the Smith degradation.

ß-1,3-d-glucan with different degrees of branching were obtained by selectively and gradually removing side chains from schizophyllan, a water-soluble triple helical polysaccharide, using the Smith degradation. Size exclusion chromatography combined with a multi-angle light scattering detection was performed in aqueous 0.1 M NaCl. The degree of branching decreased after the Smith degradation, while the molar mass distributions were almost unchanged. The molecular conformation of the Smith-degraded ß-1,3-d-glucan was analyzed on the basis of the molar mass dependency of the radius gyration, and found to be comparable to the original triple helix of schizophyllan. Differential scanning calorimetry in deuterium oxide-hexadeuterodimethylsulfoxide mixtures was performed to investigate the effects of the degree of branching on the cooperative order-disorder transition. Removal of side chains affects both the transition temperature and transition enthalpy. The ordered structure is formed by the residual side chains in the triplex unit, so that the linear cooperative system of the triplex is maintained after the Smith degradation.

Electrospun Schizophyllan/polyvinyl alcohol blend nanofibrous scaffold as potential wound healing.

In this study, aqueous Schizophyllan (SPG) (1.5 w/v%) was mixed with aqueous polyvinyl alcohol (PVA) (10 w/v%) at various volume ratios and electrospun to prepare nanofibers. The fiber diameter was decreased by increasing the SPG content. A reliable linear relationship (p < 0.01) was established between the solution properties and fiber diameter. Contiguous, bead-free, and smooth fibers were obtained when the SPG/PVA ratios were 20:80, 30:70, and 40:60. FT-IR spectra, SEM images, tensile testing, swelling ratios, and water contact angle were utilized to characterize this glutaraldehyde (Glu) vapor cross-linked nanofibers in order to analyze the morphology, functional groups, mechanical attributes, hydrophilicity, and humidity of the nanofibers for skin tissue regeneration. Furthermore, the cell culture that was studied by the use of fibroblast (L929) cells showed that these SPG-based nanofibrous scaffolds could generate the improved cell adhesion. In conclusion, it was observed that SPG/PVA nanofiber mat in a volume ratio of 20:80 after 3 day was a suitable material for improving the wound healing, as it could increase cell proliferation and migration that possessed fiber diameter. The characteristics of this nanofiber were 267 nm, contact angle of 47.75°, good swelling behavior (289%), the ultimate strength of 6.513 MPa, Young modulus of 2.665 MPa, and cell viability of 150%.

Complex consisting of antisense DNA and ß-glucan promotes internalization into cell through Dectin-1 and hybridizes with target mRNA in cytosol.

Antisense oligonucleotides (AS-ODNs) hybridize with specific mRNAs, resulting in interference with the splicing mechanism or the regulation of protein translation. We previously demonstrated that the ß-glucan schizophyllan (SPG) can form a complex with AS-ODNs with attached dA40 (AS-ODNs/SPG), and this complex can be incorporated into cells, such as macrophages and dendritic cells, expressing the ß-glucan receptor Dectin-1. We have achieved efficient gene silencing in animal models, but the uptake mechanism and intracellular distribution are unclear. In this study, we prepared the complex consisting of SPG and AS-ODNs (AS014) for Y-box binding protein-1 (YB-1). After treatment with endocytosis inhibitor Pitstop 2 and small interfering RNA targeting Dectin-1, we found that AS014/SPG complexes are incorporated into cells by Dectin-1-mediated endocytosis and inhibit cell growth in a Dectin-1 expression level-dependent manner. After treatment with AS014/SPG complexes, we separated the cell lysate into endosomal and cytoplasmic components by ultracentrifugation and directly determined the distribution of AS014 by reverse transcription PCR using AS014 ODNs as a template or a reverse transcription primer. In the cytoplasm, AS014 clearly hybridized with YB-1 mRNAs. This is the first demonstration of the distinct distribution of the complex in cells. These results could facilitate the clinical application of the complex.

Synthesis and characterization of schizophyllan nanogels via inverse emulsion using biobased materials.

Oxidized sucrose cross-linked Schizophyllan nanogel was successfully synthesized via inverse emulsion method for the first time. The synthesis process was conducted in the absence of both toxic cross-linker and organic solvent. The nanogel crosslinking network was prepared using fractionated coconut oil as the continuous phase and oxidized sucrose as the cross-linker. The formation of ether linkage on schizophyllan cross-linked structure was confirmed by Fourier transform infrared microscopy (FTIR) analysis. Size and morphology were evaluated by DLS analysis and SEM. The results showed that increasing the concentration of surfactant causes the decrease in the size. By keeping surfactant amounts constant, the increase in the amount of crosslinker caused increase in the size and swelling degree. Nontoxicity of the nanogels was proved by in vitro MTT analysis. The obtained nanogels, possess special properties such as high water content, colloidal stability, bioactivity, functionality, and interior network for drug loading capacity offer great potential for the utilization of nanogels in biomedical applications.

Designing an immunocyte-targeting delivery system by use of beta-glucan.

A ß-1,3-d-glucan called Schizophyllan (SPG) can form a novel complex with homo oligodeoxynucleotides (ODNs) via the combination of hydrogen bonding and hydrophobic interactions. Dectin-1 is a major receptor involved in the recognition of ß-1,3-d-glucans and expressed on antigen presenting cells (APCs) including macrophages, dendritic cells, monocytes, neutrophils, and a subset of T cells. Therefore, the SPG/ODN complex can be used as APCs cell-specific delivery of functional ODNs including unmethylated CpG sequences (CpG-ODNs). In fact, CpG-ODN/SPG complex induced high antibody titers when it was administered to cynomolgus monkeys as adjutant of influenza vaccine. These results indicate that SPG can be an excellent immunocyte-targeting drug delivery system.

Implications of recovery procedures on structural and rheological properties of schizophyllan produced from date syrup.

This study investigates the effects of different recovery procedures on high molar mass schizophyllan produced by Schizophyllum commune using low value agricultural residues. Recovered extracellular polysaccharides (EPSs) were compared in terms of purity, sugar composition, degree of branching, molecular weight, and rheological properties. Performing different recovery methods, such as re-dissolving in water and re-precipitation with ethanol on produced EPS, provided schizophyllan with purity similar to the commercial grade. Besides, Freeze-thawing cycles allowed the fractionation of schizophyllan based on branching degree and solubility. The EPSs with higher purity and lower degree of branching (less conformational flexibility) showed higher viscosity. This study evidences the possibility of producing EPSs with excellent rheological properties using low value agricultural side products. Furthermore, our results demonstrate the importance of recovery methods for tailoring the purity, molecular structure and macroscopic properties of the produced polysaccharides for specific applications.

Complex Consisting of ß-Glucan and Antigenic Peptides with Cleavage Site for Glutathione and Aminopeptidases Induces Potent Cytotoxic T Lymphocytes.

The efficient induction of antigen-specific immune responses requires not only promotion of the uptake of antigens and adjuvant molecules into antigen-presenting cells but also control of their intracellular behavior. We previously demonstrated that the ß-glucan schizophyllan (SPG) can form complexes with CpG oligonucleotides with attached dA40 (CpG-dA/SPG), which can accumulate in macrophages in the draining inguinal lymph nodes and induce strong immune responses. In this study, we prepared various conjugates composed of antigenic peptide (OVA257-264) and dA40 and made complexes with SPG. The conjugates with a disulfide bond between OVA257-264 and dA40 were easily cleaved by glutathione. The resultant peptides with a hydrophobic amino acid at the C-terminal end was recognized by puromycin-insensitive leucine aminopeptidase (PILS-AP), which trims antigenic peptide precursors and prepares peptides of eight or nine amino acids in length, which is the optimal length for binding to major histocompatibility complex (MHC)-I. The conjugate exposed to such enzymes induced a high antigen presentation level. The antigen presentation level was almost the same before and after the complexation with SPG. Immunization with a mixture of dA-OVA257-264/SPG and CpG-dA/SPG induced high antigen-specific cytotoxic T-lymphocyte activity at a much lower peptide dose than in previous studies. These results can be strongly ascribed to not only the cell-specific delivery by SPG but also the control of the intracellular behavior by the introduction of cleavage sites. Therefore, peptide-dA/SPG complexes could be used as potent vaccine antigens for the treatment of cancers and infectious diseases.

Effects of carboxylation of the side chains on the order-disorder transition in aqueous solution of schizophyllan, a triple helical polysaccharide.

Schizophyllan and scleroglucan are water-soluble polysaccharides having repeating units consisting of three ß-1,3-linked glucose residues in the main chain and a single ß-1,6-linked glucose residue as the side chain. This polysaccharide dissolves as a triple helix in an aqueous solution and shows a cooperative order-disorder transition between the side chain and solvent molecules while retaining the triple helical conformation. Periodate and subsequent chlorite oxidations selectively modify the side chain glucose to provide the corresponding dicarboxylate units. Optical rotation measurements and differential scanning calorimetry were performed on carboxylated schizophyllan/scleroglucan ('sclerox') samples to investigate the effects of the degree of carboxylation on the order-disorder transition in deuterium oxide with 0.1M NaCl. The transition curves for the sclerox samples are strongly dependent on the degree of carboxylation. The modified side chains cannot take the ordered structure, resulting in a reduction of the transition enthalpy. The transition temperature for carboxylated schizophyllan becomes lowered and the transition curve broadens with increasing the degree of carboxylation. The permanent disordered units are included in a trimer by the carboxylation to inhibit a long sequence of the ordered units.