Molecular dynamics simulation of lentinan and its interaction with the innate receptor dectin-1

Insights into oral lentinan immunomodulation: Dectin-1-mediated lymphatic transport from Peyer's patch M cells to mononuclear phagocytes

Lentinan (LNT), a natural polysaccharide, has been reported to exhibit immunomodulatory effects in the intestine after oral administration. Herein, we aimed to investigate the lymphatic transport of LNT in Peyer's patches (PPs) by traceable fluorescent labeling and to explore whether/how LNT contacts related immune cells. Near-infrared imaging confirmed the absorption of LNT in the small intestinal segment and its accumulation within PPs after oral administration. Subsequently, tissue imaging confirmed that M cells are the main cells responsible for transporting LNT to PPs, and an M cell model was established to explore the involvement of Dectin-1 in the absorption process. Systematic in vitro and in vivo studies revealed that the Dectin-1 further mediates the uptake of LNT by mononuclear phagocytes in PPs. Moreover, LNT can promote the proliferation and differentiation of mononuclear phagocytes, thereby activating immune responses. In summary, this study elucidates the pharmacokinetic mechanisms by which LNT exerts oral immunomodulatory effects, providing a theoretical basis for the development and application of other polysaccharides.

Advances in carbohydrate-based nanoparticles for targeted therapy of inflammatory bowel diseases: A review

The incidence of inflammatory bowel disease (IBD), a chronic gastrointestinal disorder, is rapidly increasing worldwide. Unfortunately, the current therapies for IBD are often hindered by premature drug release and undesirable side effects. With the advancement of nanotechnology, the innovative targeted nanotherapeutics are explored to ensure the accurate delivery of drugs to specific sites in the colon, thereby reducing side effects and improving the efficacy of oral administration. The emphasis of this review is to summarize the potential pathogenesis of IBD and highlight recent breakthroughs in carbohydrate-based nanoparticles for IBD treatment, including their construction, release mechanism, potential targeting ability, and their therapeutic efficacy. Specifically, we summarize the latest knowledge regarding environmental-responsive nano-systems and active targeted nanoparticles. The environmental-responsive drug delivery systems crafted with carbohydrates or other biological macromolecules like chitosan and sodium alginate, exhibit a remarkable capacity to enhance the accumulation of therapeutic drugs in the inflamed regions of the digestive tract. Active targeting strategies improve the specificity and accuracy of oral drug delivery to the colon by modifying carbohydrates such as hyaluronic acid and mannose onto nanocarriers. Finally, we discuss the challenges and provide insight into the future perspectives of colon-targeted delivery systems for IBD treatment.

The dispersibility of biphasic stabilized oil-in-water emulsions improved by the interaction between curdlan and soy protein isolate

Curdlan, a natural polysaccharide, exhibits emulsion-stabilizing and viscosity-modifying properties. However, when employed solely in the aqueous phase, curdlan's adhesive nature impedes droplet dispersion, resulting in a gel-like structure with limited applicability. This investigation formulated a biphasic stabilized oil-in-water emulsion by supplementing the oil phase with beeswax and the aqueous phase with curdlan and soy protein isolate (SPI). The addition of SPI transformed the structural characteristics from a gel-like to a mayonnaise-like structure. Maximal electrostatic repulsion was observed at an internal phase volume fraction of 30%, effectively precluding droplet aggregation owing to the absolute zeta potentials surpassing 40 mV. The emulsions displayed shear-thinning rheological behavior, with a higher storage modulus than the loss modulus, indicative of favorable elastic properties. Molecular docking revealed the predominant role of polar amino acids in facilitating hydrogen bond formation. This study provides a template for developing emulsions with biphasic stability and desirable dispersibility.

One-step construction of silver nanoparticles immersed hydrogels by triple-helix β-glucans and the application in infectious wound healing

Hydrogels composed of polysaccharides and silver nanoparticles (AgNPs) are widely recognized for their applications in wound dressings, particularly for healing wounds prone to infection. Traditional methods for preparing AgNPs immersed hydrogels are often complex, costly, and may lead to sustained cytotoxicity. To address these challenges, we developed a biocompatible, one-step green reduction strategy to generate AgNPs within hydrogels using a triple-helix β-glucan (PCPA) derived from Poria cocos, a renowned Chinese traditional herb. PCPA serves as a reducing agent, converting silver ions into AgNPs while its triple-helix conformation prevents AgNPs aggregation. The resulting hydrogel (PAg-G) is injectable and contains uniformly distributed AgNPs. PAg-G exhibits broad-spectrum antimicrobial activity and enhanced bioactivity. The in vivo study on S.aureus-infected SD rats demonstrated that PAg-G can accelerate wound healing within 12 days by down-regulating inflammatory factors such as IL-6 and TNF-α, and up-regulating VEGF and CD31 expression, promoting neovascularization in wound tissues. This innovative one-step construction of AgNPs immersed hydrogels offers a promising approach for the development of antimicrobial hydrogels, especially for treating bacterial-infected wounds.

Intestinal lymphatic transport of Smilax china L. pectic polysaccharide via Peyer's patches and its uptake and transport mechanisms in mononuclear phagocytes

Recently, the intestinal lymphatic transport based on Peyer's patches (PPs) is emerging as a promising absorption pathway for natural polysaccharides. Herein, the aim of this study is to investigate the PP-based oral absorption of a pectic polysaccharide from Smilax china L. (SCLP), as well as its uptake and transport mechanisms in related immune cells. Taking advantages of the traceability of fluorescently labeled SCLP, we confirmed that SCLP could be absorbed into PPs and captured by their mononuclear phagocytes (dendritic cells and macrophages) following oral administration. Subsequently, the systematic in vitro study suggested that the endocytic mechanisms of SCLP by model mononuclear phagocytes (BMDCs and RAW264.7 cells) mainly involved caveolae-mediated endocytosis, macropinocytosis and phagocytosis. More importantly, SCLP directly binds and interacts with toll-like receptor 2 (TLR2) and galectin 3 (Gal-3) receptor, and was taken up by mononuclear phagocytes in receptor-mediated manner. After internalization, SCLP was intracellularly transported primarily through endolysosomal pathway and ultimately localized in lysosomes. In summary, this work reveals novel information and perspectives about the in vivo fate of SCLP, which will contribute to further research and utilization of SCLP and other pectic polysaccharides.

Lentinan Ameliorates β-Hydroxybutyrate-Induced Lipid Metabolism Disorder in Bovine Hepatocytes by Upregulating the Expression of Acetyl-coenzyme A Acetyltransferase 2

Ketosis in dairy cows is often accompanied by the dysregulation of lipid homeostasis in the liver. Acetyl-coenzyme A acetyltransferase 2 (ACAT2) is specifically expressed in the liver and is important for regulating lipid homeostasis in ketotic cows. Lentinan (LNT) has a wide range of pharmacological activities, and this study investigates the protective effects of LNT on β-hydroxybutyrate (BHBA)-induced lipid metabolism disorder in bovine hepatocytes (BHECs) and elucidates the underlying mechanisms. BHECs were first pretreated with LNT to investigate the effect of LNT on BHBA-induced lipid metabolism disorder in BHECs. ACAT2 was then silenced or overexpressed to investigate whether this mediated the protective action of LNT against BHBA-induced lipid metabolism disorder in BHECs. Finally, BHECs were treated with LNT after silencing ACAT2 to investigate the interaction between LNT and ACAT2. LNT pretreatment effectively enhanced the synthesis and absorption of cholesterol, inhibited the synthesis of triglycerides, increased the expression of ACAT2, and elevated the contents of very low-density lipoprotein and low-density lipoprotein cholesterol, thereby ameliorating BHBA-induced lipid metabolism disorder in BHECs. The overexpression of ACAT2 achieved a comparable effect to LNT pretreatment, whereas the silencing of ACAT2 aggravated the effect of BHBA on inducing disorder in lipid metabolism in BHECs. Moreover, the protective effect of LNT against lipid metabolism disorder in BHBA-induced BHECs was abrogated upon silencing of ACAT2. Thus, LNT, as a natural protective agent, can enhance the regulatory capacity of BHECs in maintaining lipid homeostasis by upregulating ACAT2 expression, thereby ameliorating the BHBA-induced lipid metabolism disorder.

Impact of molecular weight and gastrointestinal digestion on the immunomodulatory effects of Lycium barbarum polysaccharides

In traditional Chinese medicine, Lycium barbarum is of rich medicinal value, and its polysaccharides are particularly interesting due to their significant pharmacological effects and potential health benefits. This study investigated the immunomodulatory effects of Lycium barbarum polysaccharides (LBPs) by examining their interaction with the TLR4/MD-2 complex and the impacts of gastrointestinal digestion on these interactions. We discovered that the affinity binding of LBPs for TLR4/MD-2 and their cytokine induction capability are influenced by molecular weight, with medium-sized LBPs (100-300 kDa) exhibiting stronger binding affinity and induction capability. Conversely, LBPs smaller than 10 kDa showed reduced activity. Additionally, the content of arabinose and galactose within the LBPs fractions was found to correlate positively with both receptor affinity and cytokine secretion. Simulated gastrointestinal digestion resulted in the degradation of LBPs into smaller fragments that are rich in glucose. Although these fragments exhibited decreased binding affinity to the TLR4/MD-2 complex, they maintained their activity to promote cytokine production. Our findings highlight the significance of molecular weight and specific monosaccharide composition in the immunomodulatory function of LBPs and emphasize the influence of gastrointestinal digestion on the effects of LBPs. This research contributes to a better understanding of the mechanisms underlying the immunomodulatory effects of traditional Chinese medicine polysaccharides and their practical application.

Glucan polysaccharides isolated from Lactarius hatsudake Tanaka mushroom: Structural characterization and in vitro bioactivities

Commercially available mushroom polysaccharides have found widespread use as adjuvant tumor treatments. However, the bioactivity of polysaccharides in Lactarius hatsudake Tanaka (L. hatsudake), a mushroom with both edible and medicinal uses, remains relatively unexplored. To address this gap, five L. hatsudake polysaccharides with varying molecular weights were isolated, named LHP-1 (898 kDa), LHP-2 (677 kDa), LHP-3 (385 kDa), LHP-4 (20 kDa), and LHP-5 (4.9 kDa). Gas chromatography-mass spectrometry, nuclear magnetic resonance, and atomic force microscopy, etc., were employed to determine their structural characteristics. The results confirmed that spherical aggregates with amorphous flexible fiber chains dominated the conformation of the LHP. LHP-1 and LHP-2 were identified as glucans with α-(1,4)-Glcp as the main chain; LHP-3 and LHP-4 were classified as galactans with varying molecular weights but with α-(1,6)-Galp as the main chain; LHP-5 was a glucan with β-(1,3)-Glcp as the main chain and β-(1,6)-Glcp connecting to the side chains. Significant differences were observed in inhibiting tumor cell cytotoxicity and the antioxidant activity of the LHPs, with LHP-5 and LHP-4 identified as the principal bioactive components. These findings provide a theoretical foundation for the valuable use of L. hatsudake and emphasize the potential application of LHPs in therapeutic tumor treatments.

Screening of Poria cocos polysaccharide with immunomodulatory activity and its activation effects on TLR4/MD2/NF-κB pathway

PCP-W1, the Poria cocos polysaccharide with the strong immunomodulatory activity, was isolated through column chromatography and screened for in vitro immune activity in RAW 264.7 cells in this study. The structure analysis results revealed that the PCP-W1 were composed of galactose, glucose, fucose and mannose in a molar percentage of 35.87: 28.56: 21.77: 13.64. And it exhibited a random coil and branched conformational features with a molecular weight of 18.38 kDa. The main chain consisted of residues→3)-β-D-Glcp-(1 → 3,6)-β-D-Glcp-(1 → 3)-β-D-Glcp-(1 → 6)-β-D-Glcp-(1 → 6)-α-D-Galp-(1 → 6)-α-D-Galp-(1 → 2,6)-α-D-Galp-(1→6)-α-D-Galp-(1 → 6)-α-D-Galp-(1 → , while branching occurred at β-D-Glcp-(1→, α-D-Manp-(1→, and α-L-Fucp-(1 → 3)- α-L-Fucp-(1→. The pharmacodynamic studies demonstrated that PCP-W1 activated the release of NO, IL-6, IL-β, TNF-α, CD86, and ROS to induce polarization of RAW 264.7 murine macrophages towards M1-type through modulation of the TLR4/MD2/NF-κB pathway. The molecular docking results showed that PCP-W1 could primarily dock onto the hydrophobic binding site of TLR4/MD2 complex via its galactose chain. Furthermore, molecular dynamics simulation displayed stable modeling for TLR4-MD2-PCP-W1 complex. Overall, we screened the most immunoactive components of the polysaccharide, analyzed its structure, demonstrated its impact on TLR4/MD2/NF-kB pathway, and studied the interaction between TLR4/MD2 and the polysaccharide fragments. These results provide further support for the structure-activity relationship study of the immunomodulatory effects of Poria cocos polysaccharide.

Isolation Techniques, Structural Characteristics, and Pharmacological Effects of Phellinus Polysaccharides: A Review

Phellinus is a precious perennial medicinal fungus. Its polysaccharides are important bioactive components, and their chemical composition is complex. The polysaccharides are mainly extracted from the fruiting body and mycelium. The yield of the polysaccharides is dependent on the extraction method. They have many pharmacological activities, such as antitumor, immunomodulatory, antioxidant, hypoglycemic, anti-inflammatory, etc. They are also reported to show minor toxic and side effects. Many studies have reported the anticancer activity of Phellinus polysaccharides. This review paper provides a comprehensive examination of the current methodologies for the extraction and purification of Phellinus polysaccharides. Additionally, it delves into the structural characteristics, pharmacological activities, and mechanisms of action of these polysaccharides. The primary aim of this review is to offer a valuable resource for researchers, facilitating further studies on Phellinus polysaccharides and their potential applications.

Impacts of monosaccharide composition on immunomodulation by cello-pentaose, manno-pentaose, and xylo-pentaose: Unraveling the underlying molecular mechanisms

Different types of functional oligosaccharides exhibit varying degrees of immune-enhancing effects, which might be attributable to differences in their glycosyl structures. The differences in the immunomodulatory action of three functional oligosaccharides with distinct glycosyl compositions: cello-oligosaccharides (COS), manno-oligosaccharides (MOS), and xylo-oligosaccharides (XOS), were investigated in mouse-derived macrophage RAW264.7. Moreover, the immune enhancement mechanism of oligosaccharides with diverse glycosyl compositions was investigated from a molecular interaction perspective. The TLR4-dependent immunoregulatory effect of functional oligosaccharides was shown by measuring the levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 in RAW264.7 cells treated with different functional oligosaccharides, both with and without Resatorvid [TAK-242] (a Toll-like receptor 4 [TLR4] inhibitor). Western blot analysis showed that binding of the three oligosaccharides to TLR4 activated the downstream signaling pathway and consequently enhanced the immune response. The fluorescence spectra and molecular docking results revealed that the main mechanisms by which these oligosaccharides attach to the TLR4 active pocket are hydrogen bonds and van der Waals forces. Functional oligosaccharides were ranked according to their affinity for TLR4, as follows: MOS > COS > XOS, indicating that oligosaccharides or polysaccharides containing mannose units may confer significant advantages for immune enhancement.

Sulfate glycosaminoglycan from swim bladder exerts immunomodulatory potential on macrophages via toll-like receptor 4 mediated NF-κB signaling pathways

This study explored the immunomodulatory impact and potential mechanisms on macrophages RAW264.7 using a purified macromolecular sulfate glycosaminoglycan (SBSG) from the swim bladder, whose structure was similar to chondroitin sulfate A. The results showed that SBSG at 0.25-1 mg/mL increased the viability and phagocytosis of RAW264.7 cells. Meanwhile, SBSG promoted the secretion of tumor necrosis factor α (TNF-α), interleukin 10 (IL-10), and nitric oxide (NO), as well as the production of reactive oxygen species (ROS). According to the RT-PCR and Western blot data, SBSG activated TLR4-nuclear factor kappa B (NF-κB) signaling pathways, which decreased the relative mRNA and protein levels of Toll-like receptor 4 (TLR4), IκB kinase β (IKKβ), NF-κB p65, and p-NF-κB p65. The molecular docking and molecular dynamic simulation findings revealed that the main binding force between TLR4 and SBSG was conventional hydrogen bond interaction, resulting in more stable ligand receptor complexes. In summary, SBSG exhibits significant immunomodulatory potential, similar to chondroitin sulfate C. The underlying molecular mechanism involved the binding of SBSG through hydrogen bonding to TLR4 receptors, triggering the NF-κB signaling pathway to downregulate the expression of related genes and proteins. This, in turn, regulated the secretion of various cytokines that were mediated by macrophages to exert the immunity of the body.

Natural polysaccharides and their derivatives targeting the tumor microenvironment: A review

Polysaccharides have gained attention as valuable supplements and natural medicinal resources, particularly for their anti-tumor properties. Their low toxicity and potent anti-tumor effects make them promising candidates for cancer prevention and treatment. The tumor microenvironment is crucial in tumor development and offers potential avenues for novel cancer therapies. Research indicates that polysaccharides can positively influence the tumor microenvironment. However, the structural complexity of most anti-tumor polysaccharides, often heteropolysaccharides, poses challenges for structural analysis. To enhance their pharmacological activity, researchers have modified the structure and properties of natural polysaccharides based on structure-activity relationships, and they have discovered that many polysaccharides exhibit significantly enhanced anti-tumor activity after chemical modification. This article reviews recent strategies for targeting the tumor microenvironment with polysaccharides and briefly discusses the structure-activity relationships of anti-tumor polysaccharides. It also summarises the main chemical modification methods of polysaccharides and discusses the impact of chemical modifications on the anti-tumor activity of polysaccharides. The review aims to lay a theoretical foundation for the development of anti-tumor polysaccharides and their derivatives.

Lentinan progress in inflammatory diseases and tumor diseases

Shiitake mushrooms are a fungal food that has been recorded in Chinese medicine to nourish the blood and qi. Lentinan (lLNT) is an active substance extracted from shiitake mushrooms with powerful antioxidant, anti-inflammatory, anti-tumor functions. Inflammatory diseases and cancers are the leading causes of death worldwide, posing a serious threat to human life and health and posing enormous challenges to global health systems. There is still a lack of effective treatments for inflammatory diseases and cancer. LNT has been approved as an adjunct to chemotherapy in China and Japan. Studies have shown that LNT plays an important role in the treatment of inflammatory diseases as well as oncological diseases. Moreover, clinical experiments have confirmed that LNT combined with chemotherapy drugs has a significant effect in improving the prognosis of patients, enhancing their immune function and reducing the side effects of chemotherapy in lung cancer, colorectal cancer and gastric cancer. However, the relevant mechanism of action of the LNT signaling pathway in inflammatory diseases and cancer. Therefore, this article reviews the mechanism and clinical research of LNT in inflammatory diseases and tumor diseases in recent years.

Elucidating binding mechanisms of naringenin by alpha-chymotrypsin: Insights into non-binding interactions and complex formation

As an inevitable parameter in the description of enzyme properties, the investigation of enzyme-ligand interactions has attracted a lot of attention. Alpha-Chymotrypsin (α-Chy) is essential for protein digestion and plays an important role in human health. Naringenin (NAG) as a potent antioxidant has recently been applied in the pharmaceutical industry. Using multispectral methods and computational simulation techniques, the binding strength of NAG to α-Chy was investigated in this research. UV-vis and fluorescence quenching data showed significant spectral changes upon binding of NAG to α-Chy. As demonstrated by fluorescence techniques, NAG could employ a static quenching process to decrease the intrinsic fluorescence of α-Chy. Both circular dichroism (CD) and FTIR spectroscopic analyses revealed that binding of NAG to α-Chy caused more flexible conformation. The slight increases in RMSD (0.06 nm) were observed for the NAG-(α-Chy) compound was supported by the results of thermal stability data. Docking computation confirmed that hydrogen and Van der Waals interactions are the important forces, which is in exact agreement with thermodynamics studies. Kinetic analysis of the enzyme showed an increase in activity, which was consistent, with the MD simulation results. The findings from the in-silico studies were in complete agreement with the experimental results.

Atomic force microscopy based conformation and immunological activity of Lentinan injections

The purpose of this study was to investigate the morphological characteristics of different brands of lentinan injections produced in China using atomic force microscopy (AFM) and their relationship to immunological activity. Based on AFM imaging, chain height could be used as characterizing the conformation of lentinan, and the heights of 95 % confidence interval for triple, double and single helix were 1.746 ± 0.039 nm, 1.564 ± 0.037 nm and 1.243 ± 0.031 nm, respectively, which were calculated using self-developed MATLAB protocol. AFM characters and their immunological activity of different lentinan injection were compared. In detail, two parameters, triple helix ratio 51.3 % and adhesion force 800 pN, of Jinling (JL) lentinan injection are much higher than samples of other four manufacturers. In addition, immunological activity of JL lentinan injection is also significantly higher than Yineng's. High performance size exclusion chromatography (HPSEC) profiles of different lentinans were also compared, and the data were in accordance with those from AFM. Molecular weight accumulation curves could be used for evaluation of quality consistence of different batches of lentinan from same manufacturer and/or different manufacturers. The results showed that quality consistence of lentinan from different manufactures is poor, which should be greatly improved.

Metabolic degradation of polysaccharides from Lentinus edodes by Kupffer cells via the Dectin-1/Syk signaling pathway

It had been shown that lentinan (LNT) was mainly distributed in the liver after intravenous administration. The study aimed to investigate the integrated metabolic processes and mechanisms of LNT in the liver, as these have not been thoroughly explored. In current work, 5-([4,6-dichlorotriazin-2-yl] amino) fluorescein and cyanine 7 were used to label LNT for tracking its metabolic behavior and mechanisms. Near-infrared imaging demonstrated that LNT was captured mainly by the liver. Kupffer cell (KC) depletion reduced LNT liver localization and degradation in BALB/c mice. Moreover, experiments with Dectin-1 siRNA and Dectin-1/Syk signaling pathway inhibitors showed that LNT was mainly taken up by KCs via the Dectin-1/Syk pathway and promoted lysosomal maturation in KCs via this same pathway, which in turn promoted LNT degradation. These empirical findings offer novel insights into the metabolism of LNT in vivo and in vitro, which will facilitate the further application of LNT and other β-glucans.

Effect of soy protein isolate nanoparticles loaded with litsea cubeba essential oil on performance of lentinan edible films

Environmental issues caused by plastic packaging materials have gotten increasingly severe, and substantial research has been conducted on environmentally friendly active packaging materials. In this study, the Litsea cubeba essential oil loaded soy protein isolate nanoparticles (LSNPs) with appropriate particle size, high storage stability and salt solution stability were fabricated. The LSNPs with the highest encapsulation efficiency of 81.76 % were added into the lentinan edible film. The microstructures of the films were observed by scanning electron microscopy. The physical properties of the films were measured. The results show that the lentinan film with LSNPs in the volume ratio of 4:1 (LF-4) had the highest elongation at break of 196 %, the lowest oxygen permeability of 12 meq/kg, and good tensile strength, water vapor barrier property, antibacterial property, oxidation resistance and thermal stability. The study suggested that LF-4 film could inhibit the growth of bacteria and delay the oxidation of lipid and protein on beef surface for 7 d.

Preparation methods, structural characteristics, and biological activity of polysaccharides from Salvia miltiorrhiza: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Salvia miltiorrhiza is a traditional Chinese medicine with the application of more than a two-thousand-year history. It is a common medicine used in the clinical treatment of cardiovascular and cerebrovascular diseases and is listed as the top grade in Shennong's Classic of Materia Medica. Polysaccharide is an important chemical component of Salvia miltiorrhiza and has a variety of biological activities.

AIM OF THE STUDY

In this review, we summarized the preparation methods, structural characteristics, and biological activities of Salvia miltiorrhiza polysaccharides, as well as discussed current research problems, providing support for further research, development, and utilization.

MATERIALS AND METHODS

By inputting the search term "Salvia miltiorrhiza polysaccharides", relevant research information was obtained from databases such as Google Scholar, PubMed, VIP, Web of Science, and China Knowledge Network (CNKI).

RESULTS

It has been found that the monosaccharide composition of Salvia miltiorrhiza polysaccharides containing glucose (Glc), galactose (Gal), mannose (Man), and arabinose (Ara) has antioxidant, anti-tumor, liver protection, and other activities.

CONCLUSIONS

We summarized the preparation methods, structural information, and biological activities of Salvia miltiorrhiza polysaccharides in this review and discussed the issues that are currently being researched. Although this product has a wide range of biological activities and has high development and utilization potential, its structure information and structure-activity relationship require further investigation.

Lentinan: An unexplored novel biomaterial in drug and gene delivery applications

Recently, lentinan (LNT) has been utilized for its diversified potential in research with an extended role from nutritional or medicinal applications to a novel biomaterial. LNT is a biocompatible, multifunctional polysaccharide employed as a pharmaceutical additive in engineering customized drug or gene carriers with an improved safety profile. Its triple helical structure containing hydrogen bonding offers more extraordinary binding sites for the attachments of dectin-1 receptors and polynucleotide sequences (poly(dA)). Hence, the diseases expressing dectin-1 receptors can be specifically targeted through so-designed LNT-engineered drug carriers. Gene delivery using poly(dA)-s-LNT complexes and composites has exhibited greater targetability and specificity. The achievement of such gene applications is assessed through the pH and redox potential of the extracellular cell membrane. The steric hindrance-acquiring behavior of LNT shows promise as a system stabilizer in drug carrier engineering. LNT shows viscoelastic gelling behavior temperature-dependently and therefore needs to explore more to meet topical disease applications. The immunomodulatory and vaccine adjuvant properties of LNT help in mitigating viral infections too. This review highlights the new role of LNT as a novel biomaterial, particularly in drug delivery and gene delivery applications. In addition, its importance in achieving various biomedical applications is also discussed.

The Structural Characterization and Immunomodulatory Activity of Polysaccharides from Pleurotus abieticola Fruiting Bodies

Polysaccharides obtained from mushrooms have been reported to possess immunomodulatory properties. In this study, a water-soluble polysaccharide was purified from the fruiting bodies of Pleurotus abieticola, entitled PAPS1. After its composition and structural analysis, the immunomodulatory activity was investigated in immunosuppressed mice induced by cyclophosphamide (CTX) at a dosage of 70 mg/kg by intraperitoneal injection for 7 days. After 28 days of intragastric administration, PAPS1 alleviated cyclophosphamide (CTX)-induced histopathological damage and increased the expressions of splenic CD4, CD8, CD56 and IgM in the serums of immunosuppressed mice. PAPS1 suppressed the oxidative stress indicated by preventing the increases in ROS and MDA levels. According to the intestinal microflora analysis, PAPS1 regulated 11 bacteria at the gene level, including Helicobacter and Paraprevotella, which are related to immunity and oxidative capacity. Compared with CTX-treated mice, significant increases in immune-related cytokines, such as interleukin (IL)-2, IL-6 and IL-12 in the serums of mice treated with PAPS1, were observed. Finally, PAPS1 can strongly increase the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream proteins. In conclusion, PAPS1-boosted immunity may be related to its suppression on oxidative stress via enhancing the activity of Nrf2 signaling. Thus, PAPS1 can be investigated as a candidate for immunomodulatory therapy.

Structural Elucidation, Modification, and Structure-Activity Relationship of Polysaccharides in Chinese Herbs: A Review

Chinese herbal polysaccharides (CHPs) are natural polymers composed of monosaccharides, which are widely found in Chinese herbs and work as one of the important active ingredients. Its biological activity is attributed to its complex chemical structure with diverse spatial conformations. However, the structural elucidation is the foundation but a bottleneck problem because the majority of CHPs are heteropolysaccharides with more complex structures. Similarly, the studies on the relationship between structure and function of CHPs are even more scarce. Therefore, this review summarizes the structure-activity relationship of CHPs. Meanwhile, we reviewed the structural elucidation strategies and some new progress especially in the advanced structural analysis methods. The characteristics and applicable scopes of various methods are compared to provide reference for selecting the most efficient method and developing new hyphenated techniques. Additionally, the principle structural modification methods of CHPs and their effects on activity are summarized. The shortcomings, potential breakthroughs, and developing directions of the study of CHPs are discussed. We hope to provide a reference for further research and promote the application of CHPs.

From Data to Knowledge: Systematic Review of Tools for Automatic Analysis of Molecular Dynamics Output

An increasing number of crystal structures available on one side, and the boost of computational power available for computer-aided drug design tasks on the other, have caused that the structure-based drug design tools are intensively used in the drug development pipelines. Docking and molecular dynamics simulations, key representatives of the structure-based approaches, provide detailed information about the potential interaction of a ligand with a target receptor. However, at the same time, they require a three-dimensional structure of a protein and a relatively high amount of computational resources. Nowadays, as both docking and molecular dynamics are much more extensively used, the amount of data output from these procedures is also growing. Therefore, there are also more and more approaches that facilitate the analysis and interpretation of the results of structure-based tools. In this review, we will comprehensively summarize approaches for handling molecular dynamics simulations output. It will cover both statistical and machine-learning-based tools, as well as various forms of depiction of molecular dynamics output.

Interaction between polysaccharides and toll-like receptor 4: Primary structural role, immune balance perspective, and 3D interaction model hypothesis

Various structural types of polysaccharides are recognized by toll-like receptor 4 (TLR4). However, the mechanism of interaction between the polysaccharides with different structures and TLR4 is unclarified. This review summarized the primary structure of polysaccharides related to TLR4, mainly including molecular weight, monosaccharide composition, glycosidic bonds, functional groups, and branched-chain structure. The optimal primary structure for interacting with TLR4 was obtained by the statistical analysis. Besides, the dual-directional regulation of TLR4 signaling cascade by polysaccharides was also elucidated from an immune balance perspective. Finally, the 3D interaction model of polysaccharides to TLR4-myeloid differentiation factor 2 (MD2) complex was hypothesized according to the LPS-TLR4-MD2 dimerization model and the polysaccharides solution conformation. The essence of polysaccharides binding to TLR4-MD2 complex is a multivalent non-covalent bond interaction. All the arguments summarized in this review are intended to provide some new insights into the interaction between polysaccharides and TLR4.

Beta-Glucans from Fungi: Biological and Health-Promoting Potential in the COVID-19 Pandemic Era

Beta-glucans comprise a group of polysaccharides of natural origin found in bacteria, algae, and plants, e.g., cereal seeds, as well as microfungi and macrofungi (mushrooms), which are characterized by diverse structures and functions. They are known for their metabolic and immunomodulatory properties, including anticancer, antibacterial, and antiviral. Recent reports suggest a potential of beta-glucans in the prevention and treatment of COVID-19. In contrast to β-glucans from other sources, β-glucans from mushrooms are characterized by β-1,3-glucans with short β-1,6-side chains. This structure is recognized by receptors located on the surface of immune cells; thus, mushroom β-glucans have specific immunomodulatory properties and gained BRM (biological response modifier) status. Moreover, mushroom beta-glucans also owe their properties to the formation of triple helix conformation, which is one of the key factors influencing the bioactivity of mushroom beta-glucans. This review summarizes the latest findings on biological and health-promoting potential of mushroom beta-glucans for the treatment of civilization and viral diseases, with particular emphasis on COVID-19.

Lentinan as a natural stabilizer with bioactivities for preparation of drug-drug nanosuspensions

Lentinan is a natural β-glucan with various bioactivities and is combined with chemotherapy drugs for cancer treatment. Regorafenib is an oral multi-kinase inhibitor approved by FDA for treatment of metastatic colorectal cancer, advanced hepatocellular carcinoma, and metastatic gastrointestinal stromal tumors. Regorafenib has poor water solubility and multiple toxicities. We report drug-drug nanosuspensions of regorafenib and lentinan. Results of dynamic light scattering and scanning electron microscopy showed that the mean particle size of the regorafenib-lentinan nanosuspensions was approximately 200 nm and was uniformly distributed. Transmission electron microscopy findings indicated that lentinan stabilized the nanosuspensions by steric manner. Hydrogen bonds and hydrophobic interactions were found between regorafenib and lentinan by molecular dynamics simulation. The results of cytotoxicity assay and pharmacokinetics study in rats showed that the regorafenib-lentinan nanosuspensions reduced the toxicity and enhanced the in vitro anticancer activity and oral bioavailability of regorafenib. Lentinan as a natural stabilizer has the potential using for drug nanosuspensions. Drug-drug nanosuspensions are a new form of combination therapies that can reduce the number of drugs taken by patients and improve their compliance.