A novel β-glucan-oligonucleotide complex selectively delivers siRNA to APCs via Dectin-1

Research progress on production and biomedical applications of Schizophyllan as a tailor-made polysaccharide: A review

Schizophyllan (SPG) is a polysaccharide of Schizophyllum commune with a β-(1 → 3)-glucan backbone structure, which has been discussed in recent years for its extensive biomedical applications. Among the biological properties of this polysaccharide are anti-cancer, antioxidant, anti-inflammatory and strengthening of the immune system. Its unique triple helix structure offers various advantages as a carrier for genes or other biomolecules. The side chains of SPG can be effectively modified to change its neutral state and produce aldehyde or carboxylate groups. This review provides a detailed evaluation of the methods of production, extraction, structure and applications of schizophyllan. First, the methods of production in solid and submerged culture of this polysaccharide and its extraction with different solvents will be investigated. Then the structure of this polysaccharide, its unique structural features, including triple helix conformation, complex formation gelation behavior will be investigated. Various modifications of this polysaccharide will be described and finally, the biomedical applications of this polysaccharide will be discussed as a therapeutic agent, the use of which can be a new path in treatment and a solution to existing challenges.

Advanced Nanotechnology-Based Nucleic Acid Medicines

Nucleic acid medicines are a highly attractive modality that act in a sequence-specific manner on target molecules. To date, 21 such products have been approved by the Food and Drug Administration. However, the development of nucleic acid medicines continues to face various challenges, including tissue and cell targeting as well as intracellular delivery. Numerous research groups are addressing these issues by advancing the development of nucleic acid medicines through nanotechnology. In countries other than Japan (including Europe and the USA), >40 nanotechnology-based nucleic acid medicines have been tested in clinical trials, and 15 clinical trials are ongoing. In Japan, three phase I trials are ongoing, and future results are awaited. The review summarizes the latest research in the nanotechnology of nucleic acid medicines and statuses of clinical trials in Japan, with expectations of further evolutions.

β-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, β-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, β-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 β-glucans applied in the drug delivery system including yeast β-glucan, Schizophyllan and curdlan, highlighting the benefits of β-glucan based delivery system. We summarize how β-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 β-glucan based delivery systems.

Glucans and applications in drug delivery

Glucan is a natural polysaccharide widely distributed in cereals and microorganisms that has various biological activities, including immunomodulatory, anti-infective, anti-inflammatory, and antitumor activities. In addition to wide applications in the broad fields of food, healthcare, and biomedicines, glucans hold promising potential as drug delivery carrier materials or ligands. Specifically, glucan microparticles or yeast cell wall particles are naturally enclosed vehicles with an interior cavity that can be exploited to carry and deliver drug payloads. The biological activities and targeting capacities of glucans depend largely on the recognition of glucan moieties by receptors such as dectin-1 and complement receptor 3, which are widely expressed on the cell membranes of mononuclear phagocytes, dendritic cells, neutrophils, and some lymphocytes. This review summarizes the chemical structures, sources, fundamental properties, extraction methods, and applications of these materials, with an emphasis on drug delivery. Glucans are utilized mainly as vaccine adjuvants, targeting ligands and as carrier materials for various drug entities. It is believed that glucans and glucan microparticles may be useful for the delivery of both small-molecule and macromolecular drugs, especially for potential treatment of immune-related diseases.

Recent advances in nano/micro systems for improved circulation stability, enhanced tumor targeting, penetration, and intracellular drug delivery: a review

In recent years, nanoparticles (NPs) have been extensively developed as drug carriers to overcome the limitations of cancer therapeutics. However, there are several biological barriers to nanomedicines, which include the lack of stability in circulation, limited target specificity, low penetration into tumors and insufficient cellular uptake, restricting the active targeting toward tumors of nanomedicines. To address these challenges, a variety of promising strategies were developed recently, as they can be designed to improve NP accumulation and penetration in tumor tissues, circulation stability, tumor targeting, and intracellular uptake. In this Review, we summarized nanomaterials developed in recent three years that could be utilized to improve drug delivery for cancer treatments.

Straight to the point: targeted mRNA-delivery to immune cells for improved vaccine design

With the deepening of our understanding of adaptive immunity at the cellular and molecular level, targeting antigens directly to immune cells has proven to be a successful strategy to develop innovative and potent vaccines. Indeed, it offers the potential to increase vaccine potency and/or modulate immune response quality while reducing off-target effects. With mRNA-vaccines establishing themselves as a versatile technology for future applications, in the last years several approaches have been explored to target nanoparticles-enabled mRNA-delivery systems to immune cells, with a focus on dendritic cells. Dendritic cells (DCs) are the most potent antigen presenting cells and key mediators of B- and T-cell immunity, and therefore considered as an ideal target for cell-specific antigen delivery. Indeed, improved potency of DC-targeted vaccines has been proved in vitro and in vivo. This review discusses the potential specific targets for immune system-directed mRNA delivery, as well as the different targeting ligand classes and delivery systems used for this purpose.

Fungal β-Glucan-Based Nanotherapeutics: From Fabrication to Application

Fungal β-glucans are naturally occurring active macromolecules used in food and medicine due to their wide range of biological activities and positive health benefits. Significant research efforts have been devoted over the past decade to producing fungal β-glucan-based nanomaterials and promoting their uses in numerous fields, including biomedicine. Herein, this review offers an up-to-date report on the synthetic strategies of common fungal β-glucan-based nanomaterials and preparation methods such as nanoprecipitation and emulsification. In addition, we highlight current examples of fungal β-glucan-based theranostic nanosystems and their prospective use for drug delivery and treatment in anti-cancer, vaccination, as well as anti-inflammatory treatments. It is anticipated that future advances in polysaccharide chemistry and nanotechnology will aid in the clinical translation of fungal β-glucan-based nanomaterials for the delivery of drugs and the treatment of illnesses.

Enhanced Therapeutic Efficacy of Immunostimulatory CpG-ODN by Silencing SOCS-1 with Polysaccharide/miR-155 Complexes

For the induction of antigen-specific immune responses, adjuvants as well as antigens are essential. CpG-ODN is a potent agonist of toll-like receptor 9 (TLR9) and is known as an adjuvant to induce cellular immune responses. We previously developed a therapeutic oligonucleotide delivery system based on the formation of a complex between schizophyllan (SPG), a kind of β-1,3-glucan, and poly(dA), which actively delivered CpG-ODN to antigen-presenting cells (APCs) in the draining lymph nodes and induced antigen-specific immune responses. However, unfortunately, the signaling pathway of TLR9 is negatively regulated by an intracellular protein called suppressor of cytokine signaling-1 (SOCS-1), which suppresses the adjuvant effect of CpG-ODN. To solve this, we focused on microRNA-155 (miR-155), which regulates innate and autoimmune processes by targeting SOCS-1. In this study, we proposed a strategy of combining miR-155 and CpG-ODN, each complexed with SPG (denoted as SPG/miR-155 and SPG/CpG, respectively), to induce a more potent immune response. As a result, we showed that the efficient delivery of miR-155 to APCs by a complex form could induce much more potent cellular immune responses than SPG/CpG alone. Furthermore, the mice treated with the combination of SPG/miR-155 and SPG/CpG showed a long delay in tumor growth occurrence and improved survival after tumor inoculation. These results indicate the possibility of therapeutic strategies for cancer.

Binding assay of human Dectin-1 variants for DNA/ β-glucan complex for active-targeting delivery of antisense DNA: Part II

A β-1,3-glucan binding receptor called Dectin-1 is mainly expressed on antigen-presenting immunocytes. Dectin-1 may be a target molecule for receptor-mediated and active-targeting delivery of drugs to regulate or interfere with the immune system. Therapeutic oligonucleotides are one such drug of interest. To this end, we have been studying the complex of schizophyllan (SPG, one of the linear (1,3)-β-ᴅ-glucan family) with oligonucleotide and its delivery mechanism to the Dectin-1 expressing cells. There are at least six types of human Dectin-1 expressed on the cell surface (designated V-1, V-2, etc.), with V-1 having a complete carbohydrate recognition domain (CRD) and stalk, V-2 having a complete CRD but no stalk, and other variants having an incomplete CRD due to exon skipping. Our previous studies have shown that SPG binds only to V-1 and V-2. By contrast, SPG/oligonucleotide complexes bind both V-1 and V-2 more strongly than SPG itself and show a certain affinity, for other variants. As a continuing work, the present paper discusses the structure and nature of all human Dectin-1 variants expressed on the cellular surface. we found that (1) a new N-linked glycosylation site is present in some variants, (2) the glycosylation of Dectin-1 plays an important role in the fate of Dectin-1 and its localization in the cells, and (3) the glycosylation is related to the amount of ingestion of the complex. The present findings suggest that, in addition to V-1 and V-2, two other variants that are highly expressed at the plasma membrane and stabilized by the glycosylation may also be targets of the complex.

siRNA against CD40 delivered via a fungal recognition receptor ameliorates murine acute graft-versus-host disease

Acute graft-versus-host disease (aGvHD) remains a major threat to a successful outcome after allogeneic hematopoietic stem cell transplantation (HSCT). Although antibody-based targeting of the CD40/CD40 ligand costimulatory pathway can prevent aGvHD, side effects hampered their clinical application, prompting a need for other ways to interfere with this important dendritic T-cell costimulatory pathway. Here, we used small interfering RNA (siRNA) complexed with β-glucan allowing the binding and uptake of the siRNA/β-glucan complex (siCD40/schizophyllan [SPG]; chemical modifications called NJA-312, NJA-302, and NJA-515) into Dectin1+ cells, which recognize this pathogen-associated molecular pattern receptor. aGvHD was induced by the transplantation of splenocytes and bone marrow cells from C57BL/6J into CBF1 mice. Splenic dendritic cells retained Dectin1 expression after HSCT but showed lower expression after irradiation. The administration of siCD40/SPG, NJA-312, and NJA-302 ameliorated aGvHD-mediated lethality and tissue damage of spleen and liver, but not skin. Multiple NJA-312high injections prevented aGvHD but resulted in early weight loss in allogeneic HSCT mice. In addition, NJA-312 treatment caused delayed initial donor T and B-cell recovery but resulted in stable chimerism in surviving mice. Mechanistically, NJA-312 reduced organ damage by suppressing CCR2+, F4/80+, and IL17A-expressing cell accumulation in spleen, liver, and thymus but not the skin of mice with aGvHD. Our work demonstrates that siRNA targeting of CD40 delivered via the PAMP-recognizing lectin Dectin1 changes the immunological niche, suppresses organ-specific murine aGvHD, and induces immune tolerance after organ transplantation. Our work charts future directions for therapeutic interventions to modulate tissue-specific immune reactions using Pathogen-associated molecular pattern (PAMP) molecules like 1,3-β-glucan for cell delivery of siRNA.