Yeast (1 → 3)-(1 → 6)-β-d-glucan alleviates immunosuppression in gemcitabine-treated mice

Lipid-like gemcitabine diester-loaded liposomes for improved chemotherapy of pancreatic cancer

Gemcitabine (GEM) is a non-selective chemotherapeutic agent used in the treatment of pancreatic cancer. Its antitumor efficacy is limited by a short plasma half-life and severe adverse reactions. To overcome these shortcomings, four novel lipid-like GEM diesters were synthesized and encapsulated into liposomes. Through optimization, dimyristoyl GEM (dmGEM)-loaded liposomes (LipodmGEM) were successfully obtained with an almost complete encapsulation efficiency. Compared to free GEM, LipodmGEM showed enhanced cellular uptake and cell apoptosis, improved inhibition of cell migration on AsPC-1 cells and a greatly extended half-life (7.22 vs. 1.78 h). LipodmGEM succeeded in enriching the drug in the tumor (5.28 vs. 0.03 μmol/g at 8 h), overcoming a major shortcoming of GEM, showed excellent anticancer efficacy in vivo and negligible systemic toxicity, superior to GEM. Attractive as well, suspensions of LipodmGEM remained stable at 2-10 °C away from light for no <2 years. Our results suggest that LipodmGEM might become of high interest for treating pancreatic cancer while the simple strategy we reported might be explored as well for converting other antitumor drugs with high water-solubility and short plasma half-life into attractive nanomedicines.

The combination of gemcitabine and ginsenoside Rh2 enhances the immune function of dendritic cells against pancreatic cancer via the CARD9-BCL10-MALT1 / NF-κB pathway

Cold tumor immune microenvironment (TIME) of pancreatic cancer (PC) with minimal dendritic cell (DC) and T cell infiltration can result in insufficient immunotherapy and chemotherapy. While gemcitabine (GEM) is a first-line chemotherapeutic drug for PC, its efficacy is reduced by immunosuppression and drug resistance. Ginsenoside Rh2 (Rh2) is known to have anti-cancer and immunomodulatory properties. Combining GEM with Rh2 may thus overcome immunosuppression and induce lasting anti-tumor immunity in PC. Here, we showed that after GEM-Rh2 therapy, there was significantly greater tumor infiltration by DCs. Caspase recruitment domain-containing protein 9 (CARD9), a central adaptor protein, was strongly up-regulated DCs with GEM-Rh2 therapy and promoted anti-tumor immune responses by DCs. CARD9 was found to be a critical target for Rh2 to enhance DC function. However, GEM-Rh2 treatment did not achieve the substantial anti-PC efficacy in CARD9^-/- mice as in WT mice. The adoptive transfer of WT DCs to DC-depleted PC mice treated with GEM-Rh2 elicited strong anti-tumor immune responses, although CARD9^-/- DCs were less effective than WT DCs. Our results showed that GEM-Rh2 may reverse cold TIME by enhancing tumor immunogenicity and decreasing the levels of immunosuppressive factors, reactivating DCs via the CARD9-BCL10-MALT1/ NF-κB pathway. Our findings suggest a potentially feasible and safe treatment strategy for PC, with a unique mechanism of action. Thus, Rh2 activation of DCs may remodel the cold TIME and optimize GEM chemotherapy for future therapeutic use.

Effects of ultrasound-assisted H2O2 on the solubilization and antioxidant activity of yeast β-glucan

Yeast β-glucan (YG) possess an extensive range of biological activities, such as the inhibition of oxidation, but the poor water solubility of macromolecular YG limits its application. In this study, through the combined degradation of ultrasonic waves and H₂O₂, and the optimization of the main process parameters for solubilizing YG by response surface methodology (RSM), a new product of YG_UH was generated. The molecular weight, structural characteristics and degradation kinetics before and after solubilization were evaluated. The results showed that the optimal solubilization conditions were reaction time: 4 h, ultrasonic power: 3 W/mL, H₂O₂ concentration: 24 %. Under these conditions, ultrasound-assisted H₂O₂ increased the solubility (from 13.60 % to 70.00 %) and reduced molecular weight (from 6.73 × 10⁶ Da to 1.22 × 10⁶ Da). Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), Congo red (CR), scanning electron microscopy (SEM) revealed that ultrasound-assisted H₂O₂ increased the conformation's flexibility greatly, without changing the main structure of YG. More importantly, solubilization of YG improved free radical scavenging activity with YG_UH exhibiting the highest levels of DPPH and ABTS⁺ free radical scavenging activity. These results revealed that ultrasound-assisted H₂O₂ degradation could be a suitable way to increase the solubility of YG for producing value-added YG.

Oral administration of botryosphaeran [(1 → 3)(1 → 6)-β-d-glucan] reduces inflammation through modulation of leukocytes and has limited effect on inflammatory nociception

Several biological activities of the fungal exopolysaccharide (1 → 3)(1 → 6)-β-d-glucan (botryosphaeran) have been described in the literature, but its effects on inflammation have not been evaluated. This study aimed to investigate the action of botryosphaeran on experimental mice models of carrageenan-induced acute pleurisy and acute paw edema, and complete Freund's adjuvant-induced persistent paw edema. All botryosphaeran doses tested (1.0, 2.5, 5.0, and 10.0 mg/kg birth weight [b.w.], orally administered) reduced leukocyte recruitment, nitric oxide (NO) levels, and protein extravasation in the pleural cavity. Botryosphaeran (5 mg/kg b.w.) did not diminish edema and mechanical hyperalgesia in the paw within 4 h; however, cold allodynia was alleviated within the first 2 h. In the persistent paw inflammation model, the effects of daily oral administration of botryosphaeran (5 mg/kg b.w.) were evaluated over 3 and 7 days. The fungal β-glucan significantly reduced the levels of the cytokines, tumor necrosis factor(TNF)-α, interleukin (IL)-6), and IL-10, in the paw homogenates in both protocols, while paw edema and the levels of advanced oxidation protein products (AOPP) only diminished on Day 7. No effect in mechanical hyperalgesia was observed. Oral treatment for 3 or 7 days also decreased the plasma levels of NO, AOPP, TNF-α, and IL-10. On Day 7, the number of leukocytes in the blood was also reduced by this treatment. Importantly, botryosphaeran did not induce inflammation in mice when administered alone over 7 days. This study demonstrated the anti-inflammatory and antinociceptive potential of botryosphaeran in these experimental models, making this fungal β-glucan a new possibility for complementary treating acute and chronic inflammation.

Oral administration of Euglena gracilis paramylon ameliorates chemotherapy-induced leukocytopenia and gut dysbiosis in mice

Euglena gracilis (EUG) is a food supplement rich in beta-glucans, which are stored in the form of granules called paramylon. We determined whether EUG improved chemotherapy-induced leukocytopenia and dysbiosis. Mice were orally administered EUG prior to gemcitabine treatment. Analyses of the blood cell count, leukocyte population in the spleen, granulocyte/macrophage-colony-stimulating factor (GM-CSF) production by splenocytes, and fecal microbiome were conducted. The recovery of total leukocytes, neutrophils, and monocytes was accelerated after a single gemcitabine treatment. A more rapid lymphocyte recovery rate was observed after four gemcitabine treatments. No difference was observed in the percentage of T, B, or myeloid cells or in the expression of Dectin-1 in the spleens of the gemcitabine and EUG/gemcitabine groups. The EUG/gemcitabine group showed an enhanced GM-CSF production by lipopolysaccharides-stimulated splenocytes. Next-generation sequencing revealed that gemcitabine-induced dysbiosis was alleviated. This study demonstrated that EUG-derived beta-glucans could act as a biological response modifier as well as prebiotics for ameliorating chemotherapy-induced adverse effects.

CD44-targeting hydrophobic phosphorylated gemcitabine prodrug nanotherapeutics augment lung cancer therapy

Gemcitabine (GEM) is among the most used chemotherapies for advanced malignancies including non-small cell lung cancer. The clinical efficacy of GEM is, however, downplayed by its poor bioavailability, short half-life, drug resistance, and dose-limiting toxicities (e.g. myelosuppression). In spite of many approaches exploited to improve the efficacy and safety of GEM, limited success was achieved. The short A6 peptide (sequence: Ac-KPSSPPEE-NH₂) is clinically validated for specific binding to CD44 on metastatic tumors. Here, we designed a robust and CD44-specific GEM nanotherapeutics by encapsulating hydrophobic phosphorylated gemcitabine prodrug (HPG) into the core of A6 peptide-functionalized disulfide-crosslinked micelles (A6-mHPG), which exhibited reduction-triggered HPG release and specific targetability to CD44 overexpressing tumor cells. Interestingly, A6 greatly enhanced the internalization and inhibitory activity of micellar HPG (mHPG) in CD44 positive A549 cells, and increased its accumulation in A549 cancerous lung, leading to potent repression of orthotopic tumor growth, depleted toxicity, and marked survival benefits compared to free HPG and mHPG (median survival time: 59 days versus 30 and 45 days, respectively). The targeted delivery of gemcitabine prodrug with disulfide-crosslinked biodegradable micelles appears to be a highly appealing strategy to boost gemcitabine therapy for advance tumors. STATEMENT OF SIGNIFICANCE: Gemcitabine (GEM) though widely used in clinics for treating advanced tumors is associated with poor bioavailability, short half-life and dose-limiting toxicities. Development of clinically translatable GEM formulations to improve its anti-tumor efficacy and safety is of great interest. Here, we report on CD44-targeting GEM nanotherapeutics obtained by encapsulating hydrophobic phosphorylated GEM prodrug (HPG), a single isomer of NUC-1031, into A6 peptide-functionalized disulfide-crosslinked micelles (A6-mHPG). A6-mHPG demonstrates stability against degradation, enhanced internalization and inhibition toward CD44⁺ cells, and increased accumulation in A549 lung tumor xenografts, leading to potent repression of orthotopic tumor growth, depleted toxicity and marked survival benefits. The targeted delivery of GEM prodrug using A6-mHPG is a highly appealing strategy to GEM cancer therapy.

β-Glucans from Yeast—Immunomodulators from Novel Waste Resources

β-glucans are a large class of complex polysaccharides with bioactive properties, including immune modulation. Natural sources of these compounds include yeast, oats, barley, mushrooms, and algae. Yeast is abundant in various processes, including fermentation, and they are often discarded as waste products. The production of biomolecules from waste resources is a growing trend worldwide with novel waste resources being constantly identified. Yeast-derived β-glucans may assist the host’s defence against infections by influencing neutrophil and macrophage inflammatory and antibacterial activities. β-glucans were long regarded as an essential anti-cancer therapy and were licensed in Japan as immune-adjuvant therapy for cancer in 1980 and new mechanisms of action of these molecules are constantly emerging. This paper outlines yeast β-glucans’ immune-modulatory and anti-cancer effects, production and extraction, and their availability in waste streams.

Effect of β-Glucan Supplementation on Growth Performance and Intestinal Epithelium Functions in Weaned Pigs Challenged by Enterotoxigenic Escherichia coli

Background: To examine the effect of β-glucan (BGL) supplementation on growth performance and intestinal epithelium functions in weaned pigs upon Enterotoxigenic Escherichia coli (ETEC) challenge. Methods: Thirty-two weaned pigs (Duroc × Landrace × Yorkshire) were assigned into four groups. Pigs fed with a basal diet or basal diet containing 500 mg/kg BGL were orally infused with ETEC or culture medium. Results: Results showed BGL tended to increase the average daily gain (ADG) in ETEC-challenged pigs (0.05 < p < 0.1). Dietary BGL supplementation had no significant influence on nutrient digestibility (p > 0.05). However, BGL improved the serum concentrations of immunoglobulin (Ig) A and IgG, and was beneficial to relieve the increasement of the concentrations of inflammatory cytokines such as the TNF-α and IL-6 upon ETEC-challenge (p < 0.05). Interestingly, BGL significantly increased the duodenal, jejunal and ileal villus height, and increased the jejunal ratio of villus height to crypt depth (V/C) upon ETEC challenge (p < 0.05). BGL also increased the activities of mucosal, sucrase and maltase in the ETEC-challenged pigs (p < 0.05). Moreover, BGL elevated the abundance of Lactobacillus and the concentration of propanoic acid in colon in the ETEC-challenged pigs (p < 0.05). Importantly, BGL elevated the expression levels of zonula occludins-1 (ZO-1) and mucin-2 (MUC-2) in the small intestinal mucosa upon ETEC challenge (p < 0.05). BGL also upregulated the expressions of functional genes such as the claudin-1, cationic amino acid transporter-1 (CAT-1), LAT-1, L amino acid transporter-1 (LAT1), fatty acid transport proteins (FATP1), FATP4, and sodium/glucose cotransporter-1 (SGLT-1) in the duodenum, and the occludin-1 and CAT-1 in the jejunum upon ETEC challenge (p < 0.05). Conclusions: These results suggested that BGL can attenuate intestinal damage in weaned pigs upon ETEC challenge, which was connected with the suppressed secretion of inflammatory cytokines and enhanced serum immunoglobulins, as well as improved intestinal epithelium functions and microbiota.

Engineering Nano- and Microparticles as Oral Delivery Vehicles to Promote Intestinal Lymphatic Drug Transport

Targeted oral delivery of a drug via the intestinal lymphatic system (ILS) has the advantages of protecting against hepatic first-pass metabolism of the drug and improving its pharmacokinetic performance. It is also a promising route for the oral delivery of vaccines and therapeutic agents to induce mucosal immune responses and treat lymphatic diseases, respectively. This article describes the anatomical structures and physiological characteristics of the ILS, with an emphasis on enterocytes and microfold (M) cells, which are the main gateways for the transport of particulate delivery vehicles across the intestinal epithelium into the lymphatics. A comprehensive overview of recent advances in the rational engineering of particulate vehicles, along with the challenges and opportunities that they present for improving ILS drug delivery, is provided, and the mechanisms by which such vehicles target and transport through enterocytes or M cells are discussed. The use of naturally sourced materials, such as yeast microcapsules and their derived polymeric β-glucans, as novel ILS-targeting delivery vehicles is also reviewed. Such use is the focus of an emerging field of research. Their potential use in the oral delivery of nucleic acids, such as mRNA vaccines, is proposed.

An overview on interactions between natural product-derived β-glucan and small-molecule compounds

β-Glucans are widely found in plants and microorganisms, which has a variety of functional activities. During production and application, interactions with other components have a great influence on the structure and functional properties of β-glucan. In this paper, interactions (including non-covalent interaction and free-radical reaction) between natural product derived β-glucan and ascorbic acid, polyphenols, bile acids/salts, metal ion or other compounds were summarized. Besides, the mechanism and influence factors of interactions between β-glucan and small-molecule compounds, and their effects on the functional properties of β-glucan were detailed. This review aims to develop an understanding and practical suggestions on interactions between β-glucan and small-molecule compounds, which is expected to provide a useful reference for processing and application.

Polysaccharides catabolism by the human gut bacterium -Bacteroides thetaiotaomicron: advances and perspectives

In recent years, the degradation processes of polysaccharides by human gut microbiota are receiving considerable attention due to the discoveries of the powerful function of gut microbiota. Gut microbiota has developed a sensitive, accurate, and complex system for sensing, capturing, and degrading different polysaccharides. Among the gut microbiota, Bacteroides thetaiotaomicron, a representative species of Bacteroides, is considered as the best degrader of polysaccharides and a potential probiotic in pharmaceutical and food industries. Here, we summarize the degradation system of B. thetaiotaomicron and the degradation pathways of different polysaccharides by B. thetaiotaomicron. We also describe a technical route for investigating a specific polysaccharide degradation pathway by human gut bacteria. In addition, we also provide the future perspectives in the development of novel polysaccharides or oligosaccharides drugs, precision microbiology medicine, and personalized nutrition.

Characterization of the secondary structure and order-disorder transition of a β-(1 → 3, 1 → 6)-glucan from Aureobasidium pullulans

This study revealed the secondary structures of the water-soluble Aureobasidium pullulans β-(1 → 3, 1 → 6)-d-glucan (APG) whose primary structural unit is a β-(1 → 3)-d-glucan backbone with four β-(1 → 6)-d-glucosyl branching units every six residues. Solid-state NMR spectroscopy, X-ray diffractometry (XRD), and small-angle X-ray scattering (SAXS) experiments involving samples prepared from lyophilized APG showed that APG forms a triple helix in H₂O and a random structure in DMSO. In addition, it was revealed that the transformation from the triple helix of APG to the random structure occurs reversibly, and that the triple helix is recovered from the random structure in DMSO/H₂O mixtures containing more than 30% H₂O. Solid-state NMR and diffraction studies revealed that the triple helix of APG is more stable than that of schizophyllan (SPG) whose structure comprises a β-(1 → 3)-d-glucan backbone with one β-(1 → 6)-d-branching unit every three residues. The APG helical pitch is 1.82 nm, which is about 10% longer than that of the triple helix of SPG. These findings show that the β-(1 → 6) side-chain frequency strongly affects the stability and helical pitch of a β-(1 → 3, 1 → 6)-d-glucan.

Dioxin-like (DL-) polychlorinated biphenyls induced immunotoxicity through apoptosis in mice splenocytes via the AhR mediated mitochondria dependent signaling pathways

Polychlorinated biphenyls (PCBs) would do serious damage to multiple systems, while coplanar polychlorinated biphenyls, the most toxic member of the family, has been widely taken into consideration. In this study, ICR mice were fed with different doses of PCB126 to explore the underlying molecular mechanisms on immunotoxicity. The results showed that PCB126 caused immunosuppression as evidenced by inhibiting the ratios of thymus and spleen weights, changing the organizational structure and decreasing levels and mRNA expression of TNF-α, IFN-γ and IL-2. PCB126 inhibited the SOD activity and spurred the accumulation of MDA in spleen and thymus. Meanwhile, it also disturbed the Nrf2 signaling pathway as evidenced by up-regulating the mRNA expression of Nrf2 and Keap1. Additionally, a remarkable reduction in the mRNA expression of AhR and enhancement in the mRNA expression of Cyp1 enzymes (Cyp1a1, Cyp1a2 and Cyp1b1) were observed, which increased the ROS levels. PCB126 could increase protein expression of Bax, Caspase-3, Caspase-8 and Caspase-9, while the protein expression of Bcl-2 was decreased. In summary, the results indicated that PCB126 modulated the AhR signaling pathway, which interacted with apoptosis and oxidative stress to induce immunotoxicity, enrich the immunotoxicological mechanisms of PCB126.