Mannose Receptor Mediates the Immune Response to Ganoderma atrum Polysaccharides in Macrophages

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.

Novel casein-derived immunomodulatory peptide PFPEVFG: Activity assessment, molecular docking, activity site and mechanism of action

Nowadays, there is still a gap in the knowledge of the structure-activity relationship of immunomodulatory peptides. In this study, PFPEVFG was selected as a peptide with immunomodulatory activity from casein hydrolysate by virtual screening and its immunomodulatory activity was verified by the phagocytosis, proliferation, and expression of cytokines (IL-6, IL-1β, TNF-α) and chemokines (CXCL1, CXCL2) in RAW 264.7 macrophages. Next, molecular docking and double-stranded small interfering RNA (siRNA) mutually verified that the immunomodulatory activity of PFPEVFG was mediated by TLR2/4. Furthermore, the highest occupied molecular orbital (HOMO) analysis showed that the C19 = O20 site with a HOMO contribution of 32.22988% was its active site, and the phenylalanine, where the C19 = O20 site was located, was its active amino acid. Finally, the combination of pathway inhibitors and Western blot revealed that PFPEVFG activated macrophages through the nuclear factor-κB (NF-κB) signaling pathway. In summary, this study provided a new perspective on deeply understanding the structure-activity relationship of casein-derived immunomodulatory peptides, as well as a further theoretical and technological basis for the application of immunomodulatory peptides.

Construction and performance evaluation of polyguluronic acid polysaccharides-based drug delivery systems

Polysaccharides have garnered significant attention as potential nanoparticle carriers for targeted tumor therapy due to their excellent biodegradability and biocompatibility. Polyguluronic acid (PG) is a homogeneous acidic polysaccharide fragment derived from alginate, which is found in brown algae, possesses excellent bioactivities, unique properties. This study explored the immunomodulatory activity of PG and developed PG-based nanogels through modified disulfide bonds and Ca2+ dual crosslinking. We characterized their structure, assessed their drug-loading and release properties, and ultimately validated both the safety of the nanocarrier and the in vitro anti-tumor efficacy of the encapsulated drug. Results indicated that PG significantly enhanced the proliferative activity and phagocytosis of RAW264.7 cells while promoting reactive oxygen species (ROS) production and cytokine secretion. The study identified TLR4 as the primary receptor for PG recognition in RAW264.7 cells. Furthermore, PG-based drug-carrying nanogels were prepared, exhibiting uniform sizes of about 184 nm and demonstrating exceptional encapsulation efficiency (82.15 ± 0.82 %) and drug loading capacity (8.12 ± 0.08 %). In vitro release experiments showed that these nanogels could responsively release drugs under conditions of high glutathione (GSH) reduction, facilitating drug accumulation at tumor sites and enhancing therapeutic efficacy. This research not only expands the application of PG in drug delivery systems but also provides valuable insights into leveraging natural immunomodulatory polysaccharides as carriers for targeted drug delivery.

Critical review on the research of chemical structure, bioactivities, and mechanism of actions of Dendrobium officinale polysaccharide

Dendrobium officinale (Tie-Pi-Shi-Hu) is a precious traditional Chinese medicine (TCM). The principal active components are polysaccharides (DOP), which have a high potency in therapeutic applications. However, limitations in structure analysis and underlying mechanism investigation impede its further research. This review systemically and critically summarises current understanding in both areas, and points out the influence of starch impurities and the role of gut microbiota in DOP research. As challenges faced in studying natural polysaccharide investigations are common, this review contributes to a broader understanding of polysaccharides beyond DOP.

Corrigendum: Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: a review

[This corrects the article DOI: 10.3389/fimmu.2023.1147641.].

Exploring the anti-cancer potential of Ganoderma lucidum polysaccharides (GLPs) and their versatile role in enhancing drug delivery systems: a multifaceted approach to combat cancer

There has been a growing global interest in the potential health benefits of edible natural bioactive products in recent years. Ganoderma lucidum, a medicinal mushroom, has gained attention for its decadent array of therapeutic and pharmaceutical compounds. Notably, G. lucidum exhibits significant anti-cancer effects against various cancer types. Polysaccharides, a prominent component in G. lucidum, are pivotal in conferring its diverse biological and medicinal properties. The primary focus of this study was to investigate the anti-cancer activities of G. lucidum polysaccharides (GLPs), with particular attention to their potential to mitigate chemotherapy-associated toxicity and enhance targeted drug delivery. Our findings reveal that GLPs exhibit anti-cancer effects through diverse mechanisms, including cytotoxicity, antioxidative properties, apoptosis induction, reactive oxygen species (ROS) generation, and anti-proliferative effects. Furthermore, the potential of GLPs-based nanoparticles (NPs) as delivery vehicles for bioactive constituents was explored. These GLPs-based NPs are designed to target various cancer tissues, enhancing the biological activity of encapsulated compounds. As such, GLPs derived from G. lucidum represent a promising avenue for inhibiting cancer progression, minimizing chemotherapy-related side effects, and supporting their utilization in combination therapies as natural adjuncts.

Antitumor effects of polysaccharides from medicinal lower plants: A review

Cancer is one of the leading causes of death worldwide, yet the drugs currently approved for cancer treatment are associated with significant side effects, making it urgent to develop alternative drugs with low side effects. Polysaccharides are natural polymers with ketone or aldehyde groups, which are widely found in plants and have various biological activities such as immunomodulation, antitumor and hypolipidemic. The lower plants have attracted much attention for their outstanding anticancer effects, and many studies have shown that medicinal lower plant polysaccharides (MLPPs) have antitumor activity against various cancers and are promising alternatives with potential development in the food and pharmaceutical fields. Therefore, this review describes the structure and mechanism of action of MLPPs with antitumor activity. In addition, the application of MLPPs in cancer treatment is discussed, and the future development of MLPPs is explored.

Molecular Insights into the Macrophage Immunomodulatory Effects of Scrophulariae Radix Polysaccharides

Scrophulariae Radix (SR) has been widely used in Chinese herbal compound prescriptions, health care products and functional foods. The present study aimed to investigate the immunomodulatory activity of polysaccharides from SR (SRPs) in macrophages and explore the potential mechanisms. The results showed that four SRPs fractions (SRPs40, SRPs60, SRPs80 and SRPs100) had similar absorption peaks and monosaccharide compositions, but the intensities of absorption peaks and monosaccharide contents were distinguished. All SRPs fractions significantly enhanced the pinocytic activity, promoted the production of NO and TNF-α, increased the mRNA expressions of inflammatory factors (IL-1β, IL-6, TNF-α and PTGS2) and TLR2, and elevated the phosphorylation levels of p38, ERK, JNK, p65 and IκB. Moreover, the production of NO and TNF-α stimulated by SRPs was dramatically suppressed by anti-TLR2 antibody. These results indicated that SRPs activated macrophages through MAPK and NF-κB signaling pathways via recognition of TLR2.

A review of Ganoderma lucidum polysaccharides: Health benefit, structure-activity relationship, modification, and nanoparticle encapsulation

Ganoderma lucidum polysaccharides possess unique functional properties. Various processing technologies have been used to produce and modify G. lucidum polysaccharides to improve their yield and utilization. In this review, the structure and health benefits were summarized, and the factors that may affect the quality of G. lucidum polysaccharides were discussed, including the use of chemical modifications such as sulfation, carboxymethylation, and selenization. Those modifications improve the physicochemical characteristics and utilization of G. lucidum polysaccharides, and make them more stable that could be used as functional biomaterials to encapsulate active substances. Ultimate, G. lucidum polysaccharide-based nanoparticles were designed to deliver various functional ingredients to achieve better health-promoting effects. Overall, this review presents an in-depth summary of current modification strategies and offers new insights into the effective processing techniques to develop G. lucidum polysaccharide-rich functional foods or nutraceuticals.

Innate immune receptors co-recognition of polysaccharides initiates multi-pathway synergistic immune response

The law and mechanism of the interaction between polysaccharides and pattern recognition receptors (PRRs) has been unclear. Herein, three glucomannans with different structures were selected to explore the universal mechanism for PRRs to recognize glucomannans. Screening results showed that the silence of TLR4 but not TLR2 severely blocked the production of inflammatory cytokines and the transduction of signal pathways. In-depth results revealed that the participation of myeloid differentiation protein 2 (MD2) and CD14 and the dimerization of the TLR4-MD2 complex were required for glucomannan-activated TLR4 signal transduction. Mannose receptor (MR) was also engaged in glucomannan-induced respiratory burst, endocytosis, and inflammatory signaling pathways in a spleen tyrosine kinase-dependent manner. The internalization of glucomannans into the cytoplasm by MR directly initiated complex intracellular signaling cascades. Finally, molecular docking characterized the binding energy and binding sites between glucomannans and multiple receptors from other perspectives. The essence of glucomannans recognized by PRRs was the non-covalent interaction of multiple receptors and the subsequent transmission of the signal cascade was triggered in a multi-channel and cooperative manner. As a result, the hypothesis that "Innate immune receptors co-recognition of polysaccharides initiates multi-pathway synergistic immune response" was proposed to outline these meaningful phenomena.

Immunomodulatory function and anti-tumor mechanism of natural polysaccharides: A review

Polysaccharides extracted from natural resources have attracted extensive attention in biomedical research and pharmaceutical fields, due to their medical values in anti-tumor, immunomodulation, drug delivery, and many other aspects. At present, a variety of natural polysaccharides have been developed as adjuvant drugs in clinical application. Benefit from their structural variability, polysaccharides have great potential in regulating cellular signals. Some polysaccharides exert direct anti-tumor effects by inducing cell cycle arrest and apoptosis, while the majority of polysaccharides can regulate the host immune system and indirectly inhibit tumors by activating either non-specific or specific immune responses. As the essential of microenvironment in the process of tumor development has been gradually revealed, some polysaccharides were found to inhibit the proliferation and metastasis of tumor cells via tumoral niche modulation. Here, we focused on natural polysaccharides with biomedical application potential, reviewed the recent advancement in their immunomodulation function and highlighted the importance of their signaling transduction feature for the antitumor drug development.

Polysaccharides as antioxidants and prooxidants in managing the double-edged sword of reactive oxygen species

Polysaccharides, a class of naturally occurring carbohydrates, were widely presented in animals, plants, and microorganisms. Recently, health benefits of polysaccharides have attracted much attention due to their unique characteristics in reactive oxygen species (ROS) management. ROS, by-products of aerobic metabolism linked to food consumption, exhibited a dual role in protecting cells and fostering pathogenesis collectively termed double-edged sword. Some interesting studies reported that polysaccharides could behave as prooxidants under certain conditions, besides antioxidant capacities. Potentiation of the bright side of ROS could contribute to the host defense that was vitally important for the polysaccharides acting as biological response modifiers. Correspondingly, disease prevention of polysaccharides linked to the management of ROS production was systematically described and discussed in this review. Furthermore, major challenges and future prospects were presented, aiming to provide new insight into applying polysaccharides as functional food ingredients and medicine.

Production and characterization of exopolysaccharides from salinity-induced Auxenochlorella protothecoides and the analysis of anti-inflammatory activity

The set scenario of this work was to investigate the production, physicochemical characteristics, and anti-inflammatory activities of exopolysaccharides from salinity-induced Auxenochlorella protothecoides. The results demonstrated that 10 ‰ salinity manipulation endowed preferable exopolysaccharide production by A. protothecoides. Under this salinity stress, ACPEPS1A and ACPEPS2A were purified from exopolysaccharide production by anion chromatography and molecular exclusion chromatography. ACPEPS1A exhibited a molecular weight (Mw) of 132 kDa and mainly consisted of galactose. ACPEPS2A was a heteropolysaccharide with an Mw of 170 kDa and the main monosaccharides of galactose and rhamnose with separate molar percents of 42.41 % and 35.29 %, respectively. FTIR, ¹H and ¹³C NMR supported that monosaccharide components of ACPEPS1A and ACPEPS2A possessed both α- and β-configuration pyranose rings. Further evidence indicated that ACPEPS1A and ACPEPS2A could effectively inhibit the inflammatory response in lipopolysaccharide (LPS) induced RAW264.7 cells by quenching inflammatory factor levels such as ROS, iNOS, TNF-α, and IL-6. The potential anti-inflammatory possibilities were that the monosaccharides of ACPEPS1A and ACPEPS2A possessed higher affinity with receptors on the macrophage surface than LPS and hampered LPS-induced inflammation. The findings of this work would favor innovative applications of exopolysaccharides from microalgae in complementary medicines or functional foods.

Research progress on natural β-glucan in intestinal diseases

β-Glucan, an essential natural polysaccharide widely distributed in cereals and microorganisms, exhibits extensive biological activities, including immunoregulation, anti-inflammatory, antioxidant, antitumor properties, and flora regulation. Recently, increasing evidence has shown that β-glucan has activities that may be useful for treating intestinal diseases, such as inflammatory bowel disease (IBD), and colorectal cancer. The advantages of β-glucan, which include its multiple roles, safety, abundant sources, good encapsulation capacity, economic development costs, and clinical evidence, indicate that β-glucan is a promising polysaccharide that could be developed as a health product or medicine for the treatment of intestinal disease. Unfortunately, few reports have summarized the progress of studies investigating natural β-glucan in intestinal diseases. This review comprehensively summarizes the structure-activity relationship of β-glucan, its pharmacological mechanism in IBD and colorectal cancer, its absorption and transportation mechanisms, and its application in food, medicine, and drug delivery, which will be beneficial to further understand the role of β-glucan in intestinal diseases.

Characterization and Immunological Activity of Exopolysaccharide from Lacticaseibacillus paracasei GL1 Isolated from Tibetan Kefir Grains

Two exopolysaccharide fractions (GL1-E1 and GL1-E2) of Lacticaseibacillus paracasei GL1 were isolated with the molecular weights of 3.9 × 105 Da and 8.2 × 105 Da, respectively. Both fractions possessed mannose, glucose, and galactose in molar ratios of 1.16:1.00:0.1, and 3.81:1.00:0.12, respectively. A structural arrangement of two fractions was proposed by methylation, one-dimensional and two-dimensional nuclear magnetic resonance experiments. The backbone of GL1-E1 consisted of →4)-α-D-Glcp(1→, →3,4)-α-D-Manp(1→, →3,6)-α-D-Manp(1→, →6)-α-D-Manp(1→, and →6)-α-D-Galp(1→ with α-D-Glcp at branching point. The backbone of GL1-E2 consisted of →4)-α-D-Glcp(1→, →3,4)-α-D-Manp(1→, →3,6)-α-D-Manp(1→, →6)-α-D-Manp(1→, →6)-α-D-Galp(1→, and →4)-β-D-Manp(1→, and the side chain also consisted of α-D-Manp residue. In addition, the differential scanning calorimetry (DSC) analysis indicated that both GL1-E1 and GL1-E2 had good thermal stability. Furthermore, the two fractions could promote the viability of RAW264.7 cells and exert an immunomodulatory role by enhancing phagocytosis, increasing nitric oxide (NO) release and promoting the expression of cytokines.

Regulation of innate and adaptive immunity using herbal medicine: benefits for the COVID-19 vaccination

Vaccination is a major achievement that has become an effective prevention strategy against infectious diseases and active control of emerging pathogens worldwide. In response to the coronavirus disease 2019 (COVID-19) pandemic, several diverse vaccines against severe acute respiratory syndrome coronavirus 2 have been developed and deployed for use in a large number of individuals, and have been reported to protect against symptomatic COVID-19 cases and deaths. However, the application of vaccines has a series of limitations, including protective failure for variants of concern, unavailability of individuals due to immune deficiency, and the disappearance of immune protection for increasing infections in vaccinated individuals. These aspects raise the question of how to modulate the immune system that contributes to the COVID-19 vaccine protective effects. Herbal medicines are widely used for their immune regulatory abilities in clinics. More attractively, herbal medicines have been well accepted for their positive role in the COVID-19 prevention and suppression through regulation of the immune system. This review presents a brief overview of the strategy of COVID-19 vaccination and the response of the immune system to vaccines, the regulatory effects and mechanisms of herbal medicine in immune-related macrophages, natural killer cells, dendritic cells, and lymphocytes T and B cells, and how they help vaccines work. Later in the article, the potential role and application of herbal medicines in the most recent COVID-19 vaccination are discussed. This article provides new insights into herbal medicines as promising alternative supplements that may benefit from COVID-19 vaccination.

Graphical abstract

http://links.lww.com/AHM/A31.

Herb Polysaccharide-Based Drug Delivery System: Fabrication, Properties, and Applications for Immunotherapy

Herb polysaccharides (HPS) have been studied extensively for their healthcare applications. Though the toxicity was not fully clarified, HPS were widely accepted for their biodegradability and biocompatibility. In addition, as carbohydrate polymers with a unique chemical composition, molecular weight, and functional group profile, HPS can be conjugated, cross-linked, and functionally modified. Thus, they are great candidates for the fabrication of drug delivery systems (DDS). HPS-based DDS (HPS-DDS) can bypass phagocytosis by the reticuloendothelial system, prevent the degradation of biomolecules, and increase the bioavailability of small molecules, thus exerting therapeutic effects. In this review, we focus on the application of HPS as components of immunoregulatory DDS. We summarize the principles governing the fabrication of HPS-DDS, including nanoparticles, micelles, liposomes, microemulsions, hydrogels, and microneedles. In addition, we discuss the role of HPS in DDS for immunotherapy. This comprehensive review provides valuable insights that could guide the design of effective HPS-DDS.

The Regulation of Micro-Organisms' Extra-Cellular Polysaccharides on Immunity: A Meta-Analysis

Extra-cellular polysaccharides (EPSs) have excellent immunomodulatory functions. In order to further promote their application, we studied the ability of extra-cellular polysaccharides from different sources to regulate immunity. We studied the association of extra-cellular polysaccharides with immune factors (Interleukin (IL-2, IL-4, IL-10), Interferon γ (IFN-γ), tumor necrosis factor-α (TNF-α), Immunoglobulin A (IgA), and Immunoglobulin G (IgG)) and different concentrations of EPSs and interfering media on experimental results by using a forest plot under fixed-effect or random-effects models. Through Google, PubMed, Embase, ScienceDirect, and Medline, from 2000 to 2021, 12 articles were included. We found that exopolysaccharides (from bacteria or fungi) could significantly increase the immune index of spleen and thymus, spleen index (SMD: 2.11, ‘95%CI: [1.15, 3.08]’; p < 0.01), and thymus index (SMD: 1.62, ‘95%CI: [0.93, 2.32]’; p = 0.01 < 0.05). In addition, exopolysaccharides had a significant effect on TNF-α (SMD: 0.94, ‘95%CI: [0.29, 1.59]’; p = 0.01 < 0.05). For IL-4 (SMD: 0.49, ‘95%CI: [0.01, 0.98]’; p = 0.046 < 0.05), extra-cellular polysaccharides had a statistically significant effect on immunity. Although the data of other immune factors were not ideal, the comprehensive analysis showed that exopolysaccharides also had an effect on the release of these five immune factors. In the sub-group analysis, different concentrations of EPSs affected the results of experiments on the spleen and thymus, and the CY intervention had a relatively significant effect on immune regulation. Taken together, our study highlighted that EPSs have a significant impact on immune regulation.

Structural characterization and immunomodulatory activity of a mannan from Helvella leucopus

A new polysaccharide fraction HLP-1 (2.55 × 10⁵ Da) was obtained from the fruiting bodies of Helvella leucopus. Structural characterization of HLP-1 was elucidated by infrared spectroscopy, monosaccharide composition analysis, methylation analysis, nuclear magnetic resonance spectroscopy, scanning electron microscopy and Congo red assay. HLP-1 was a mannan with a backbone of →6)-α-D-Manp(1 → 4)- α-D-Manp(1 → 6)-α-D-Manp(1 → 3)-α-D-Manp(1 → 4)-α-D-Manp(1 → 3)-α-D-Manp(1→, which branched at the O-6 position and terminated with T-β-D-Manp. Moreover, HLP-1 could significantly improve the proliferation and neutral red phagocytosis of RAW264.7. Besides, HLP-1 could stimulate the production of nitric oxide (NO), ROS, tumor necrosis factor-α (TNF-α), interleukin-1 beta (IL-1β) and interleukin-6 (IL-6). HLP-1 induced macrophage activation via NF-κB signal pathway. These findings indicated that HLP-1 was a potential immune enhancement agent applied in functional foods.

The Main Structural Unit Elucidation and Immunomodulatory Activity In Vitro of a Selenium-Enriched Polysaccharide Produced by Pleurotus ostreatus

In recent years, the structure of selenium-enriched polysaccharides and their application in immunomodulation have attracted much attention. In previous studies, we extracted and purified a novel selenium-enriched Pleurotus ostreatus polysaccharide called Se-POP-21, but its structure and immunomodulatory activity were still unclear. In this study, the main structural unit formula of Se-POP-21 was characterized by methylation analysis and an NMR experiment. The results showed that the backbone of Se-POP-21 was →[2,6)-α-D-Galp-(1→6)-α-D-Galp-(1]₄→2,4)-β-L-Arap-(1→[2,6)-α-D-Galp-(1→6)-α-D-Galp-(1]₄→, branched chain of β-D-Manp-(1→ and β-D-Manp-(1→4)-β-L-Arap-(1→ connected with →2,6)-α-D-Galp-(1→ and →2,4)-β-L-Arap-(1→,respectively, through the O-2 bond. In vitro cell experiments indicated that Se-POP-21 could significantly enhance the proliferation and phagocytosis of RAW264.7 cells, upregulate the expression of costimulatory molecules CD80/CD86, and promote RAW264.7 cells to secrete NO, ROS, TNF-α, IL-1β, and IL-6 by activating the NF-κB protein. The results of this study indicate that Se-POP-21 can effectively activate RAW264.7 cells. Thus, it has the potential to be used in immunomodulatory drugs or functional foods.

Ganoderma atrum polysaccharide modulates the M1/M2 polarization of macrophages linked to the Notch signaling pathway

Macrophages could be polarized into two major sub-populations including classically activated (M1) and alternatively activated (M2) macrophages. The present study aimed to investigate the effects of Ganoderma atrum polysaccharide (PSG-1) on the regulation of macrophage polarization and further explored the associated molecular mechanisms. In this work, a lipopolysaccharide (LPS) plus IFN-γ and IL-4 were used to establish an in vitro model of two extreme states, namely pro-inflammatory M1 and anti-inflammatory M2. The results showed that PSG-1 had effects on the behavior modification of macrophage polarization by reducing CD80 expression in LPS plus IFN-γ-induced M1 macrophages, and attenuating CD23 expression in IL-4-induced M2 macrophages. Further study revealed that PSG-1-modulated M1 and M2 macrophage polarization was associated with controlling phagocytosis, reactive oxygen species generation, NO and cytokines (IL-1β, IL-6 and IL-10). Subsequently, the treatment of M1 macrophages with a combination of PSG-1 and a Notch-response inhibitor (DAPT) did not alter CD80 expression compared with DAPT alone, while several pro-inflammatory parameters were considerably decreased, suggesting that the Notch signaling pathway partly mediated the effects of PSG-1 on modulating macrophage polarization. Together, our findings suggested that PSG-1 could repair the chaos in the polarization of M1/M2 macrophages and the molecular mechanism linked to the Notch signaling pathway.

Immune-enhancing effects of β-lactoglobulin glycated with lactose following in vitro digestion on cyclophosphamide-induced immunosuppressed mice

β-Lactoglobulin (β-LG) is a major milk protein, making up more than 53% of the total whey proteins, and is seen as a valuable ingredient in food processing because of its high essential amino acid content and diverse functional applications. The Maillard reaction can occur during the storage and processing of food and generate various beneficial effects, including anti-allergenicity, antioxidant, and immunomodulatory effects. The addition of an β-LG-lactose conjugate (LGL) produced by the Maillard reaction was shown to have a strong immune-enhancing effect, increasing both nitric oxide generation and cytokine expression through activation of RAW 264.7 cells, even after in vitro digestion. Furthermore, daily LGL administration resulted in the upregulation of several immune markers in a cyclophosphamide-induced immunosuppressive mouse model, indicating that this treatment stimulates multiple immune cells, including macrophages, natural killer cells, and lymphocytes, enhancing the proliferation and activation of both the innate and adaptive immune responses. Taken together, these findings indicate that consuming LGL on a regular basis can improve immunity by increasing the natural production of various immune cells.

Dual pH-Responsive Macrophage-Targeted Isoniazid Glycoparticles for Intracellular Tuberculosis Therapy

Tuberculosis (TB) is a global epidemic that kills over a million people every year, particularly in low-resource communities. Mycobacterium tuberculosis, the most common bacterium that causes TB, is difficult to treat, particularly in its latent phase, in part due to its ability to survive and replicate within the host macrophage. New therapeutic approaches resulting in better tolerated and shorter antibiotic courses that target intracellular bacteria are critical to effective treatment. The development of a novel, pH-responsive, mannosylated nanoparticle, covalently linked with isoniazid, a first-line TB antibiotic, is presented. This nanoparticle drug delivery agent has increased macrophage uptake and, upon exposure to the acidic phagolysosome, releases isoniazid through hydrolysis of a hydrazone bond, and disintegrates into a linear polymer. Full antibiotic activity is shown to be retained, with mannosylated isoniazid particles being the only treatment exhibiting complete bacterial eradication of intracellular bacteria, compared to an equivalent PEGylated system and free isoniazid. Such a system, able to effectively kill intracellular mycobacteria, holds promise for improved outcomes in TB infection.

Mannose Receptor Mediates the Activation of Chitooligosaccharides on Blunt Snout Bream (Megalobrama amblycephala) Macrophages

Chitooligosaccharide (COS) is an important immune enhancer and has been proven to have a variety of biological activities. Our previous research has established an M1 polarization mode by COS in blunt snout bream (Megalobrama amblycephala) macrophages, but the mechanism of COS activation of blunt snout bream macrophages remains unclear. In this study, we further explored the internalization mechanism and signal transduction pathway of chitooligosaccharide hexamer (COS6) in blunt snout bream macrophages. The results showed that mannose receptor C-type lectin-like domain 4-8 of M. amblycephala (MaMR CTLD4-8) could recognize and bind to COS6 and mediate COS6 into macrophages by both clathrin-dependent and caveolin-dependent pathways. In the inflammatory response of macrophages activated by COS6, the gene expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and nitric oxide synthase 2 (NOS2) was significantly inhibited after MaMR CTLD4-8-specific antibody blockade. However, even if it was blocked, the expression of these inflammation-related genes was still relatively upregulated, which suggested that there are other receptors involved in immune regulation. Further studies indicated that MaMR CTLD4-8 and Toll-like receptor 4 (TLR4) cooperated to regulate the pro-inflammatory response of macrophages caused by COS6. Taken together, these results revealed that mannose receptor (MR) CTLD4-8 is indispensable in the process of recognition, binding, internalization, and immunoregulation of COS in macrophages of blunt snout bream.

A splenic-targeted versatile antigen courier: iPSC wrapped in coalescent erythrocyte-liposome as tumor nanovaccine

The major obstacles for tumor vaccine to be surmounted are the lack of versatile property and immunity-inducing effectiveness. Induced pluripotent stem cells (iPSCs) expressed various antigens the same as multiple types of tumors, providing a promising source of wide-spectrum cancer vaccines. The damaged erythrocyte membrane entrapped by spleen could be developed as antigen deliverer for enhancing acquired immunity. Here, the modified lipid materials were used to dilate erythrocyte membrane to fabricate coalescent nanovector, which not only preserved the biological characteristics of erythrocyte membrane but also remedied the defect of insufficient drug loading capacity. After wrapping iPSC protein, the nanovaccine iPSC@RBC-Mlipo exhibited obvious splenic accumulation, systemic specific antitumor immunity evocation, and effective tumor expansion and metastasis inhibition in mice. Hence, our research may provide a prospective strategy of efficient tumor vaccine for clinical practice.

Classification, structure and mechanism of antiviral polysaccharides derived from edible and medicinal fungus

The deficiency of chemical-synthesized antiviral drugs when applied in clinical therapy, such as drug resistance, and the lack of effective antiviral drugs to treat some newly emerging virus infections, such as COVID-19, promote the demand of novelty and safety anti-virus drug candidate from natural functional ingredient. Numerous studies have shown that some polysaccharides sourcing from edible and medicinal fungus (EMFs) exert direct or indirect anti-viral capacities. However, the internal connection of fungus type, polysaccharides structural characteristics, action mechanism was still unclear. Herein, our review focus on the two aspects, on the one hand, we discussed the type of anti-viral EMFs and the structural characteristics of polysaccharides to clarify the structure-activity relationship, on the other hand, the directly or indirectly antiviral mechanism of EMFs polysaccharides, including virus function suppression, immune-modulatory activity, anti-inflammatory activity, regulation of population balance of gut microbiota have been concluded to provide a comprehensive theory basis for better clinical utilization of EMFs polysaccharides as anti-viral agents.

Review on Auricularia auricula-judae as a Functional Food: Growth, Chemical Composition, and Biological Activities

Although the application of Auricularia auricula-judae (AAJ) for health purposes has a long tradition in Asia, there is a lack of research on the functional nutrition of AAJ; the current research focused on polysaccharides has been too unitary compared to other mushrooms in recent years. Identification, extraction, and large-scale production of biologically active substances have emerged as critical determinants that determine AAJ becoming a functional food. AAJ is being treated in a restrained manner, despite having significant potential as a drug or a source of pure bioactive substances. Functional ingredients of mushrooms and AAJ have emerged as a new impetus for researchers interested in developing functional foods. This review presents an overview of current studies relevant to nutrition and the application of AAJ. The physiological conditions of AAJ and the corresponding functional ingredients beneficial to human health are reviewed to better understand the function and mechanisms of different nutrient contents. Relevant methods for evaluating the efficiency of extraction are also summarized. Finally, current limitations and the future scope for functional ingredients of AAJ are identified and discussed.

Panax quinquefolius (North American Ginseng) Polysaccharides as Immunomodulators: Current Research Status and Future Directions

Panax quinquefolius (North American ginseng, NAG) is a popular medicinal plant used widely in traditional medicine. NAG products are currently available in various forms such as roots, extracts, nutraceuticals, dietary supplements, energy drinks, etc. NAG polysaccharides are recognized as one of the major bioactive ingredients. However, most NAG reviews are focused on ginsenosides with little information on polysaccharides. NAG polysaccharides have demonstrated a therapeutic activity in numerous studies, in which many of the bioactivities involve regulation of the immune response. The purpose of this review is to summarize the structural features and the immunomodulatory properties of crude, partially purified, and pure polysaccharides isolated from NAG. Receptors of the innate immune system that potentially bind to NAG polysaccharides and the respective signal transduction pathways initiated by these compounds are discussed. Major challenges, recent innovations, and future directions in NAG polysaccharide research are also summarized.

Carbohydrate-protein template synthesized high mannose loading gold nanoclusters: A powerful fluorescence probe for sensitive Concanavalin A detection and specific breast cancer cell imaging

Protein-encapsulated gold nanoclusters (Au NCs) have recently gained much attention in biosensing and bioimaging applications owing to their remarkable fluorescence properties, nontoxicity and good biocompatibility. In this work, the mannose was grafted onto the bovine serum albumin (BSA) encapsulated Au NCs (BSA-Au NCs) to produce a mannose functionalized BSA-Au NCs (Man-BSA-Au NCs) as a new fluorescence probe for Concanavalin A (Con A) detection and human breast cancer cell imaging. A new strategy with mannose-BSA conjugates as template was firstly applied for the synthesis of Man-BSA-Au NCs, leading to a high loading of mannose (767.6 ± 7.2 mg/L) onto BSA-Au NCs. The as-prepared Man-BSA-Au NCs showed advantages of facile preparation, good monodispersity and strong red-emission. Notably, aggregation-induced fluorescence quenching of Man-BSA-Au NCs was triggered by Con A due to the multivalent cooperative interactions between mannose and Con A, which was subsequently confirmed by MALDI-TOF MS. Hence highly selective and sensitive fluorescence detection of Con A was achieved by using Man-BSA-Au NCs as a fluorescence sensor. A good linear relationship was obtained over the range of 0.01-1 μM (R² = 0.994) with a detection limit of 0.62 nM (S/N = 3). The developed sensor was then applied to determine Con A in human serum with acceptable recoveries of 93.70-104.8%. Moreover, based on the specific recognition between mannose and overexpressed mannose receptors on human breast cancer cells, the Man-BSA-Au NCs were successfully utilized for cancer cell imaging with good specificity.

Immunomodulatory activities of polysaccharides from Ganoderma on immune effector cells

Polysaccharides are the most abundant bioactive compounds in Ganoderma and have been widely used as dietary supplements in traditional Chinese medicine for thousands of years. Polysaccharides from Ganoderma exhibit unique biological properties, including anti-tumor, anti-inflammatory, and immunomodulatory activities. Herein, the sources and structures of polysaccharides from Ganoderma were presented. This work also reviews the immunomodulatory activities and possible mechanisms of polysaccharides from Ganoderma on different immune effector cells, including lymphocytes and myeloid cells. As an available adjunctive remedy, polysaccharides from Ganoderma can potentially be applied for the modulation of the host immune system, namely the innate immunity, the cellular immunity, and the humoral immunity.

How to use macrophages to realise the treatment of tumour

Macrophages (Mø) are immune cells with natural phagocytic ability and play an important role in tumorigenesis, development and metastasis. Mø play a dual role of tumour inhibition and tumour promotion in tumour development due to their two different phenotypes. Mø in the tumour microenvironment have long been referred to as tumour-associated Mø (TAMs). Mø are mainly involved in tumour resistance, cancer metastasis and mediating immunosuppression. Nowadays, Mø and Mø membranes have been widely used in drug delivery systems (DDSs) because of their good biocompatibility, natural phagocytosis and their important role in tumour development. In this review, from the perspective of Mø's role in tumour development, we present strategies and drugs of Mø targeting and focusing on the several types of biomimetic nanoparticles constructed by Mø and Mø membranes in tumour therapy, and discuss the problem of this delivery system in present research and future directions.

Sarcodia suieae acetyl-xylogalactan regulate RAW 264.7 macrophage NF-kappa B activation and IL-1 beta cytokine production in macrophage polarization

In this study, the effects of acetyl-xylogalactan extracted from Sarcodia suieae on RAW 264.7 macrophage polarisation were evaluated. This extracted acetyl-xylogalactan had a monosaccharide composition of 91% galactose and 9% xylose, with polysaccharide and acetyl contents of 80.6% and 19.3%, respectively. MALDI-TOF mass spectrometry and NMR spectroscopy revealed the molecular weight of the acetyl-xylogalactan to be 88.5 kDa. After acetyl-xylogalactan treatment, RAW 264.7 macrophage polarisation was noted, along with enhanced phagocytic ability. Furthermore, the Cell Counting Kit-8 (CCK-8) assay was performed and the results demonstrated non-significant alteration in lactate dehydrogenase levels in the treated cells. Next, interleukin (IL) 1β, TNF, and Malt-1 expression in RAW 264.7 macrophages treated with the S. suieae acetyl-xylogalactan was investigated through real-time quantitative polymerase chain reaction, and the results demonstrated that S. suieae acetyl-xylogalactan induced IL-1β and Malt-1 expression. RNA sequencing analysis results indicated the S. suieae acetyl-xylogalactan positively regulated cytokine production and secretion, protein secretion, and response to IL-1 activation, based on the observed GO terms. The predicted target genes in the GO enrichment analysis were found to upregulate NF-κB signalling and M0 to M1 macrophage conversion through the observed cytokine production. Thus, acetyl-xylogalactan can positively regulate RAW 264.7 macrophage polarisation.

Lachnum polysaccharide suppresses S180 sarcoma by boosting anti-tumor immune responses and skewing tumor-associated macrophages toward M1 phenotype

Therapeutic strategies that targeting tumor-associated macrophages (TAMs) reprogramming play a crucial role in ameliorating the immunosuppressive tumor microenvironment and boosting anti-tumor immune responses. In this study, we demonstrated that Lachnum polysaccharide (LEP) could work as an immunomodulator to reset TAMs from pro-tumor M2 to anti-tumor M1 phenotype. Mechanistically, LEP promoted Th1 polarization and the secretion of IFN-γ, which played a key role in M1 phenotype polarization. In parallel, LEP might directly activate M1 macrophages via TLR4 mediated NF-κB signaling pathway. Moreover, LEP also resulted in the accumulation of anti-tumor immune cells and decreased the infiltration of immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and Treg cells, thereby potentiating anti-tumor immunity. In summary, these results revealed a novel mechanism of the anti-tumor effect of LEP and provided a potential new avenue targeting TAMs and cancer immunotherapy.

Investigation on activation in RAW264.7 macrophage cells and protection in cyclophosphamide-treated mice of Pseudostellaria heterophylla protein hydrolysate

Our previous study has demonstrated that Pseudostellaria heterophylla protein hydrolysate (PPH) has immunomodulatory activity on murine spleen lymphocytes. The aim of this study was to investigate the excitation of PPH in RAW264.7 macrophage cells and the protective effect in cyclophosphamide (CTX)-treated mice. The results showed PPH of 50 μg/mL could stimulate macrophages resulting in significant promotions of nitric oxide (NO) production, endocytosis and reactive oxygen species formation. Meanwhile, enzyme-linked immunosorbent assay (ELISA) revealed that the levels of tumor necrosis factor-α and interleukin-10 were significantly upregulated by PPH. Furthermore, 50 mg/kg per day PPH restored the T lymphocyte proliferation and natural killer cell activity, and increased NO production and pinocytosis of peritoneal macrophages in CTX-treated mice. These findings indicate PPH plays a crucial role in RAW264.7 macrophage cells activation and in the protection against immunosuppression in CTX-treated mice and could be used as a potential immunostimulant agent.

Mechanism of bioactive polysaccharide from Lachnum sp. acts synergistically with 5-fluorouracil against human hepatocellular carcinoma

The antimetabolite 5-fluorouracil (5-FU) is a widely used antitumor agent, however the overall response rate to 5-FU as a single agent is usually limited. Herein, how Lachnum expolysaccharide (LEP-2a), a type of active polysaccharide isolated from Lachnum sp., acted synergistically with 5-FU on HepG2 cells was investigated. It was found that LEP-2a notably enhanced 5-FU sensitivity in HepG2 cells in a synergistic manner. After combination treatment of 5-FU and LEP-2a, Ras/Raf/MEK/ERK and PI3K/AKT/mTOR pathway were inactivated. In addition, combination treatment induced generation of reactive oxygen species, decreased the levels of intracellular antioxidant enzymes and triggered mitochondrial apoptosis pathway. Furthermore, 5-FU combined with LEP-2a also resulted in p53 activation and NF-κB inhibition, and cell cycle arrest in the S phase as well as cell metastasis stagnation. Interestingly, LEP-2a treatment also blocked the DNA damage repair procedure. These findings demonstrate that LEP-2a enhanced 5-FU sensitivity and combination of 5-FU and LEP-2a exerts synergistic antitumor efficiency through multiple approaches.

TLR4, but Neither Dectin-1 nor Dectin-2, Participates in the Mollusk Hemocyanin-Induced Proinflammatory Effects in Antigen-Presenting Cells From Mammals

Mollusk hemocyanins have biomedical uses as carriers/adjuvants and nonspecific immunostimulants with beneficial clinical outcomes by triggering the production of proinflammatory cytokines in antigen-presenting cells (APCs) and driving immune responses toward type 1 T helper (Th1) polarization. Significant structural features of hemocyanins as a model antigen are their glycosylation patterns. Indeed, hemocyanins have a multivalent nature as highly mannosylated antigens. We have previously shown that hemocyanins are internalized by APCs through receptor-mediated endocytosis with proteins that contain C-type lectin domains, such as mannose receptor (MR). However, the contribution of other innate immune receptors to the proinflammatory signaling pathway triggered by hemocyanins is unknown. Thus, we studied the roles of Dectin-1, Dectin-2, and Toll-like receptor 4 (TLR4) in the hemocyanin activation of murine APCs, both in dendritic cells (DCs) and macrophages, using hemocyanins from Megathura crenulata (KLH), Concholepas concholepas (CCH) and Fissurella latimarginata (FLH). The results showed that these hemocyanins bound to chimeric Dectin-1 and Dectin-2 receptors in vitro; which significantly decreased when the glycoproteins were deglycosylated. However, hemocyanin-induced proinflammatory effects in APCs from Dectin-1 knock-out (KO) and Dectin-2 KO mice were independent of both receptors. Moreover, when wild-type APCs were cultured in the presence of hemocyanins, phosphorylation of Syk kinase was not detected. We further showed that KLH and FLH induced ERK1/2 phosphorylation, a key event involved in the TLR signaling pathway. We confirmed a glycan-dependent binding of hemocyanins to chimeric TLR4 in vitro. Moreover, DCs from mice deficient for MyD88-adapter-like (Mal), a downstream adapter molecule of TLR4, were partially activated by FLH, suggesting a role of the TLR pathway in hemocyanin recognition to activate APCs. The participation of TLR4 was confirmed through a decrease in IL-12p40 and IL-6 secretion induced by FLH when a TLR4 blocking antibody was used; a reduction was also observed in DCs from C3H/HeJ mice, a mouse strain with a nonfunctional mutation for this receptor. Moreover, IL-6 secretion induced by FLH was abolished in macrophages deficient for TLR4. Our data showed the involvement of TLR4 in the hemocyanin-mediated proinflammatory response in APCs, which could cooperate with MR in innate immune recognition of these glycoproteins.

Ingestion of Non-digestible Carbohydrates From Plant-Source Foods and Decreased Risk of Colorectal Cancer: A Review on the Biological Effects and the Mechanisms of Action

The hypothesis that links the increase in the intake of plant-source foods to a decrease in colorectal cancer (CRC) risk has almost 50 years. Nowadays, systematic reviews and meta-analysis of case-control and cohort studies confirmed the association between dietary patterns and CRC risk, in which the non-digestible carbohydrates (NDC) from plant-source foods are known to play beneficial effects. However, the mechanisms behind the physicochemical properties and biological effects induced by NDC on the decrease of CRC development and progression remain not fully understood. NDC from plant-source foods consist mainly of complex carbohydrates from plant cell wall including pectin and hemicellulose, which vary among foods in structure and in composition, therefore in both physicochemical properties and biological effects. In the present review, we highlighted the mechanisms and described the recent findings showing how these complex NDC from plant-source foods are related to a decrease in CRC risk through induction of both physicochemical effects in the gastrointestinal tract, fermentation-related effects, and direct effects resulting from the interaction between NDC and cellular components including toll-like receptors and galectin-3. Studies support that the definition of the structure-function relationship-especially regarding the fermentation-related effects of NDC, as well as the direct effects of these complex carbohydrates in cells-is crucial for understanding the possible NDC anticancer effects. The dietary recommendations for the intake of NDC are usually quantitative, describing a defined amount of intake per day. However, as NDC from plant-source foods can exert effects that vary widely according to the NDC structure, the dietary recommendations for the intake of NDC plant-source foods are expected to change from a quantitative to a qualitative perspective in the next few years, as occurred for lipid recommendations. Thus, further studies are necessary to define whether specific and well-characterized NDC from plant-source foods induce beneficial effects related to a decrease in CRC risk, thereby improving nutritional recommendations of healthy individuals and CRC patients.

Advances in Research on Immunoregulation of Macrophages by Plant Polysaccharides

Polysaccharides are among the most important members of the biopolymer family. They are natural macromolecules composed of monosaccharides. To date, more than 300 kinds of natural polysaccharide compounds have been identified. They are present in plants, animals, and microorganisms, and they engage in a variety of physiological functions. In the 1950s, due to the discovery of their immunoregulatory and anti-tumor activities, polysaccharides became a popular topic of research in pharmacology, especially in immunopharmacology. Plants are an important source of natural polysaccharides. Pharmacological and clinical studies have shown that plant polysaccharides have many functions, such as immune regulation, anti-tumor activity, anti-inflammatory activity, anti-viral functions, anti-radiation functions, and a hypoglycaemic effect. The immunomodulatory effects of plant polysaccharides have received much attention. Polysaccharides with these effects are also referred to as biological response modifiers (BRMs), and research on them is one of the most active areas of polysaccharide research. Thus, we summarize immunomodulatory effects of botanical polysaccharides isolated from different species of plants on the macrophage. The primary effect of botanical polysaccharides is to enhance and/or activate macrophage immune responses, including increasing reactive oxygen species (ROS) production, and enhancing secretion of cytokines and chemokines. Therefore, it is believed that botanical polysaccharides have significant therapeutic potential, and represent a new method for discovery and development of novel immunomodulatory medicine.

Geography and ethnicity related variation in the Chinese human milk serum proteome

Human milk provides a range of nutrients and bioactive components, which can support the growth and development of infants.

Peptide-mediated cationic micelles drug-delivery system applied on a VEGFR3-overexpressed tumor

Copolymers as a kind of drug delivery carrier always lack targeting efficiency.