Inhibition of mevalonate pathway by macrophage-specific delivery of atorvastatin prevents their pro-inflammatory polarisation

Adjustment of the cellular metabolism of pro-inflammatory macrophages is essential for their bactericidal function; however, it underlies the development of many human diseases if induced chronically. Therefore, intervention of macrophage metabolic polarisation has been recognised as a potent strategy for their treatment. Although many small-molecule inhibitors affecting macrophage metabolism have been identified, their in vivo administration requires a tool for macrophage-specific delivery to limit their potential side effects. Here, we establish Drosophila melanogaster as a simple experimental model for in vivo testing of macrophage-specific delivery tools. We found that yeast-derived glucan particles (GPs) are suitable for macrophage-specific delivery of small-molecule inhibitors. Systemic administration of GPs loaded with atorvastatin, the inhibitor of hydroxy-methyl-glutaryl-CoA reductase (Hmgcr), leads to intervention of mevalonate pathway specifically in macrophages, without affecting HMGCR activity in other tissues. Using this tool, we demonstrate that mevalonate pathway is essential for macrophage pro-inflammatory polarisation and individual's survival of infection.

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.

Magnetic Yeast Glucan Particles for Antibody-Free Separation of Viable Macrophages from Drosophila melanogaster

Currently available methods for cell separation are generally based on fluorescent labeling using either endogenously expressed fluorescent markers or the binding of antibodies or antibody mimetics to surface antigenic epitopes. However, such modification of the target cells represents potential contamination by non-native proteins, which may affect further cell response and be outright undesirable in applications, such as cell expansion for diagnostic or therapeutic applications, including immunotherapy. We present a label- and antibody-free method for separating macrophages from living Drosophila based on their ability to preferentially phagocytose whole yeast glucan particles (GPs). Using a novel deswelling entrapment approach based on spray drying, we have successfully fabricated yeast glucan particles with the previously unachievable content of magnetic iron oxide nanoparticles while retaining their surface features responsible for phagocytosis. We demonstrate that magnetic yeast glucan particles enable macrophage separation at comparable yields to fluorescence-activated cell sorting without compromising their viability or affecting their normal function and gene expression. The use of magnetic yeast glucan particles is broadly applicable to situations where viable macrophages separated from living organisms are subsequently used for analyses, such as gene expression, metabolomics, proteomics, single-cell transcriptomics, or enzymatic activity analysis.

Yeast glucan particles: An express train for oral targeted drug delivery systems

As an emerging drug delivery vehicle, yeast glucan particles (YGPs) derived from yeast cells could be specifically taken up by macrophages. Therefore, these vehicles could rely on the recruitment of macrophages at the site of inflammation and tumors to enable targeted imaging and drug delivery. This review summarizes recent advances in the application of YGPs in oral targeted delivery systems, covering the basic structure of yeast cells, methods for pre-preparation, drug encapsulation and characterization. The mechanism and validation of the target recognition interaction of YGPs with macrophages are highlighted, and some inspiring cases are presented to show that yeast cells have promising applications. The future chances and difficulties that YGPs will confront are also emphasized throughout this essay. YGPs are not only the "armor" but also the "compass" of drugs in the process of targeted drug transport. This system is expected to provide a new idea about the oral targeted delivery of anti-inflammatory and anti-tumor drugs, and furthermore offer an effective delivery strategy for targeted therapy of other macrophage-related diseases.

Serum and lymph pharmacokinetics of nilotinib delivered by yeast glucan particles per os

Nilotinib is a selective tyrosine-kinase inhibitor approved for the treatment of chronic myeloid leukemia. It is poorly soluble in aqueous media and has a low oral bioavailability. Nilotinib encapsulation into yeast glucan particles (GPs) was investigated in this work as a means of increasing bioavailability. The amorphization of nilotinib in GPs resulted in an increased dissolution rate, which was confirmed by in vitro experiments using biorelevant dissolution media. Simultaneously, GPs containing nilotinib were effectively taken up by macrophages, which was quantified in vitro on cell cultures. The overall oral bioavailability in a rat model was approximately 39 % for nilotinib delivered in a reference formulation (Tasigna) and was almost doubled when delivered in GPs. The contribution of glucan particles to the lymphatic transport of nilotinib was quantified. When delivered by GPs, cumulative nilotinib absorption via the lymphatic system increased by a factor of 10.8 compared to the reference, but still represented arelative bioavailability of only 1.12 %. The cumulative uptake of GPs in the lymph was found to be 0.54 mg after a single dose of 50 mg. Yeast glucan particles can therefore serve as a drug delivery vehicle with a dual function: dissolution rate enhancement by amorphization, and, to asmaller extent, lymphatic delivery due to macrophage uptake.

Cytosolic protein delivery via metabolic glycoengineering and bioorthogonal click reactions

Cytosolic protein delivery holds great potential for the development of protein-based biotechnologies and therapeutics. Currently, cytosolic protein delivery is mainly achieved with the assistance of various carriers. Herein, we present a universal and effective strategy for carrier-free cytosolic protein delivery via metabolic glycoengineering and bioorthogonal click reactions. Ac₄ManNAz (AAM), an azido-modified N-acetylmannosamine analogue, was first employed to label tumor cell surfaces with abundant azido groups via glycometabolism. Then, proteins including RNase A, cytochrome C (Cyt C), and bovine serum albumin (BSA) were covalently modified with dibenzocyclooctyne (DBCO). Based on the highly efficient bioorthogonal click reactions between DBCO and azido, DBCO-modified proteins could be efficiently internalized by azido-labeled cancer cells. RNase A-DBCO could largely maintain its enzymatic activity and, thus, led to notable anti-tumor efficacy in HeLa and B16F10 cells in vitro and in B16F10 xenograft tumors in vivo. This study therefore provides a simple and powerful approach for carrier-free protein delivery and would have broad applicability in anti-tumor protein therapy.

Composites of yeast glucan particles and curcumin lead to improvement of dextran sulfate sodium-induced acute bowel inflammation in rats

The goal of this work was to assess the usability of yeast glucan particles (GPs) as carriers for curcumin and determine the beneficial effect of a pharmacological composite of curcumin in GPs on dextran sulfate sodium induced colitis in rats. The assessment of the anti-inflammatory effect of particular substances was evaluated on the basis of the calculated disease activity index and by assessment of cytokines and enzymes from the gut tissue - tumor necrosis factor α (TNF-α), transforming growth factor β1, interleukin (IL)-1β, IL-6, IL-10, IL-17, catalase, superoxide dismutase 2, myeloperoxidase (MPO), and matrix metalloproteinase 9. Composites of GPs with incorporated curcumin showed promising results with the capability to lower symptoms of colitis and significantly decrease the production of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and the activity of MPO, as well. The anti-inflammatory effect of the composites was greater than those of pure GPs or curcumin.

Glucan particles as suitable carriers for the natural anti-inflammatory compounds curcumin and diplacone - Evaluation in an ex vivo model

Natural compounds offer a wide spectrum of potential active substances, but often they have a poor bioavailability. To increase the bioavailability and bioactivity of the natural anti-inflammatory molecules curcumin and diplacone, we used glucan particles (GPs), hollow shells from Saccharomyces cerevisiae composed mainly of β-1,3-d-glucan. Their indigestibility and relative stability in the gut combined with their immunomodulatory effects makes them promising carriers for such compounds. This study aimed to determine how curcumin and diplacone, either alone or incorporated in GPs, affect the immunomodulatory activity of the latter by assessing the respiratory burst response and the secretion of pro-inflammatory cytokines by primary porcine innate immune cells. Incorporating curcumin and diplacone into GPs by controlled evaporation of the organic solvent substantially reduced the respiratory burst response mediated by GPs. Incorporated curcumin in GPs also reduced GPs mediated secretion of IL-1β and TNF-α by innate immune cells. The obtained results indicate a potentially beneficial effect of the incorporation of curcumin or diplacone into GPs against inflammation.