Preparation and characterization of Chinese yam polysaccharide PLGA nanoparticles and their immunological activity

Mannose targeting of poly(lactic-co-glycolic acid): a promising approach for improving sublingual allergen-specific immunotherapy

OBJECTIVE

One of the most effective treatments for allergic respiratory diseases is allergen-specific sublingual immunotherapy (SLIT). While, mannose targeting has been applied in various immunostimulatory approaches, but it has not been investigated in sublingual allergen-specific immunosuppressive treatment. This study assesses mannose targeting for the ovalbumin (Ova) loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles(NPs).

METHODS

The emulsion-solvent evaporation method was employed for the synthesis of PLGA NPs containing Ova, and subsequently they attached to D-mannose. Ova-sensitized mice underwent treatment in different ways: subcutaneous administration of 10 µg Ova, sublingual administration of 5 and 10 µg Ova loaded in PLGA NPs, 5 and 10 µg Ova loaded in mannose-targeted PLGA NPs, 10 µg Ova, and 10 µg Ova loaded in dendritic cell-specific aptamer-attached PLGA NPs. Serum Ova-specific IgE and IgG2a levels, as well as IFN-γ, IL-4, IL-10, and IL-17a levels in the supernatant of Ova-stimulated splenocytes were measured. Splenocyte proliferation was assessed using an MTT assay, and also lung histological examinations, and nasal lavage fluid cell counting were performed.

RESULTS

Ova-specific IgE, IL-4, IL-17a levels, eosinophil cell count, and splenocyte proliferation were remarkably reduced in the mice treated with mannose or aptamer targeted NPs compared to other groups. Also, IL-10 and IFN-γ levels were remarkably increased in the targeted NPs groups.

CONCLUSION

Our findings indicated that mannose targeting of PLGA NPs could decrease allergen dose and improve immunomodulatory effects of SLIT. However, this approach suggests an effective formulation for SLIT in the mice model, further studies with common allergens are needed for application in humans.

Preparation, Characterization, and Immune Activity of Viola philippica Polysaccharide PLGA Nanoparticles

Recent pharmacological studies have demonstrated that Viola philippica polysaccharide (VPP) exhibits a modulating effect on immune activity. However, its utilization has been hampered by its large particle size and complex spatial structure. Polylactic-co-glycolic acid (PLGA) copolymer is recognized as an effective drug delivery carrier, exhibiting excellent biochemical properties. In this experiment, VPP was encapsulated with PLGA to form VPP PLGA nanoparticles (VPP-PLGA NPs). The morphological structure and immunomodulatory effects of VPP-PLGA NPs were evaluated. The particle size of VPP-PLGA NPs was reduced compared to VPP, and the optimal preparation conditions were as follows: The ratio of the organic phase to the internal aqueous phase was 8:1, the ratio of the external aqueous phase to the primary emulsion was 7:1, and the concentration of PLGA was 20 mg/mL. Additionally, VPP-PLGA NPs significantly increased the nitric oxide (NO) content, IL-4, and IFN-γ levels in RAW264.7 cells, as well as enhanced their phagocytic activity. Furthermore, VPP-PLGA NPs were found to increase NO content and IFN-γ secretion in bone marrow-derived dendritic cells (BMDCs). These findings suggest that VPP-PLGA NPs could enhance the immune activity and may be utilized as a VPP delivery system for inducing strong immune responses.

Extraction, separation and efficacy of yam polysaccharide

Yam is used as common herbal remedy in traditional Chinese medicine and is grown all over Asia. According to previous research, one of the primary bioactive components of yam is yam polysaccharide. To shed light on the mechanism of yam polysaccharide in ulcerative colitis (UC), a yam heteropolysaccharide named CYP-3a was isolated and purified using ultrasonic extraction, the trichloroacetic acid technique, DEAE cellulose-52 and a Sephadex G75 column. CYP-3a comprises rhamnus: arabinose:galactose:mannose:galacturonic acid glucuronic acid, with a molar ratio of 2.25:4.17:3.30:0.09:0.13:0.26. CCK-8 and ELISA analysis results showed that CYP-3a increased the number of dextran sodium sulphate (DSS)-induced Caco-2 cells and could reduce and inhibit their inflammatory response by lowering the amounts of secreted TNF-α and IL-6. Western blot data demonstrated that CYP-3a at various doses could suppress the endoplasmic reticulum stress-mediated apoptotic pathway generated by DSS-induced UC and down-regulate the protein levels of GRP78, CHOP and NF-κB.

Surface-Engineered Polygonatum Sibiricum Polysaccharide CaCO3 Microparticles as Novel Vaccine Adjuvants to Enhance Immune Response

Micro- and nanoparticles delivery systems have been widely studied as vaccine adjuvants to enhance immunogenicity and sustain long-term immune responses. Polygonatum sibiricum polysaccharide (PSP) has been widely studied as an immunoregulator in improving immune responses. In this study, we synthesized and characterized cationic modified calcium carbonate (CaCO3) microparticles loaded with PSP (PEI-PSP-CaCO3, CTAB-PSP-CaCO3), studied the immune responses elicited by PEI-PSP-CaCO3 and CTAB-PSP-CaCO3 carrying ovalbumin (OVA). Our results demonstrated that PEI-PSP-CaCO3 significantly enhanced the secretion of IgG and cytokines (IL-4, IL-6, IFN-γ, and TNF-α) in vaccinated mice. Additionally, PEI-PSP-CaCO3 induced the activation of dendritic cells (DCs), T cells, and germinal center (GC) B cells in draining lymph nodes (dLNs). It also enhanced lymphocyte proliferation, increased the ratio of CD4+/CD8+ T cells, and elevated the frequency of CD3+ CD69+ T cells in spleen lymphocytes. Therefore, PEI-PSP-CaCO3 microparticles induced a stronger cellular and humoral immune response and could be potentially useful as a vaccine delivery and adjuvant system.

Prospects of yam (Dioscorea) polysaccharides: Structural features, bioactivities and applications

Yam (Dioscorea) is a tuber crop cultivated for food security, revenue, and medicinal purposes. It has been used to treat diabetes, asthma, diarrhea, and other diseases. The main active ingredients in yam, polysaccharides, are regarded to be the important reason for its widespread applications. Now, a comprehensive review of research developments of yam polysaccharides (YPs) was presented to explore their prospects. We outlined the structural characteristics, biological activities, structure-activity relationships, and potential applications. Around 13 neutral components and 17 acidic components were separated. They exhibited various bioactivities, including immunomodulatory, hypoglycemic, hypolipidemic, antioxidant, gastrointestinal protective, anti-fatigue, and senile disease treatment activities, as well as prebiotic effect. Structure-activity relationships illustrated that unique structural properties, chemical modifications, and carried biopolymers could influence the bioactivities of YPs. The potential applications in medicine, food, and other fields have also been summarized.

Activates B lymphocytes and enhanced immune response: A promising adjuvant based on PLGA nanoparticle to improve the sensitivity of ZEN monoclonal antibody

In preparing monoclonal antibodies by hybridoma cell technology, the quality of B lymphocytes used for cell fusion directly affects the sensitivity of monoclonal antibodies. To obtain B-lymphocytes producing high-quality specific antibodies for cell fusion during the immunization phase of the antigen, we prepared a TH2-Cell stimulatory delivery system as a novel adjuvant. Astragalus polysaccharide has a good ability to enhance antigenic immune response, and it was encapsulated in biocompatible materials PLGA as an immunostimulatory factor to form the delivery system (APS-PLGA). The preparation conditions of APSP were optimized using RSM to attain the highest utilization of APS. Immunization against ZEN-BSA antigen using APSP as an adjuvant to obtain B lymphocytes producing ZEN-specific antibodies for cell fusion. As results present, APSP could induce a stronger TH2 immune response through differentiating CD4 T cells and promoting IL-4 and IL-6 cytokines. Moreover, it could slow down the release efficiency of ZEN-BSA and enhance the targeting of ZEN-BSA to lymph nodes in vivo experiments. Ultimately, the sensitivity of mouse serum ZEN-specific antibodies was enhanced upon completion of immunization, indicating a significant upregulation of high-quality B lymphocyte expression. In the preparation of monoclonal antibodies, the proportion of positive wells for the first screening was 60%, and the inhibition rates of the antibodies were all similar (>50%). Then we obtained the ZEN monoclonal antibody with IC50 of 0.049 ng/mL, which was more sensitive than most antibodies prepared under conventional adjuvants. Finally, a TRFIAS strip assay was preliminarily established with a LOD value of 0.246 ng/mL.

Preparation and characterization of pickering emulsion stabilized by lovastatin nanoparticles for vaccine adjuvants

While research on mevalonate inhibitors as vaccine adjuvants has made great progress to enhance the effectiveness of the vaccine, co delivery of lovastatin and antigens (OVA) remains an enormous challenge. Here, we encapsulated lovastatin into PLGA nanoparticles. PLGA loading lovastatin was further emulsified with squalene to prepare Pickering emulsion. The emulsification conditions of Pickering emulsion were optimized, and the optimal preparation conditions were obtained. After loading lovastatin and OVA, the size and zeta potential of LS-PPAS/OVA was 1043.33 nm and -22.07 mv, the adsorption rate of OVA was 63.34 %. The adsorbing of LS-PLGA nanoparticles on the surface of squalene in Pickering emulsions was demonstrated by Fluorescent confocal microscopy. After immunization, LS-PPAS enhanced the activation of dendritic cells in lymph nodes, further study found LS-PPAS not only elicited elevated levels of OVA-specific IgG and its subtypes, but also promoted the secretion of TNF-α, IFN-γ, and IL-6 in serum as a marker of cellular immunity. Importantly, LS-PPAS showed sufficient security through monitoring levels of biochemical parameters in serum and pathological observation of organ following vaccinations. LS-PPAS may act as a promising vaccine carrier to produce strong humoral and cellular immunity with acceptable safety.

Research progress on the structure, derivatives, pharmacological activity, and drug carrier capacity of Chinese yam polysaccharides: A review

Chinese yam is a traditional Chinese medicine that has a long history of medicinal and edible usage in China and is widely utilised in food, medicine, animal husbandry, and other industries. Chinese yam polysaccharides (CYPs) are among the main active components of Chinese yam. In recent decades, CYPs have received considerable attention because of their remarkable biological activities, such as immunomodulatory, antitumour, hypoglycaemic, hypolipidaemic, antioxidative, anti-inflammatory, and bacteriostatic effects. The structure and chemical alterations of polysaccharides are the main factors affecting their biological activities. CYPs are potential drug carriers owing to their excellent biodegradability and biocompatibility. There is a considerable amount of research on CYPs; however, a systematic summary is lacking. This review summarises the structural characteristics, derivative synthesis, biological activities, and their usage as drug carriers, providing a basis for future research, development, and application of CYPs.

Research Progress on Immunomodulatory Effects of Poly (Lactic-co- Glycolic Acid) Nanoparticles Loaded with Traditional Chinese Medicine Monomers

Immunomodulatory mechanisms are indispensable and key factors in maintaining the balance of the environment in humans. When the immune function of the immune system is impaired, autoimmune diseases occur. Excessive body fatigue, natural aging of the human body, malnutrition, genetic factors and other reasons cause low immune function, due to which the body is prone to being infected by bacteria or cancer. Clinically, the existing therapeutic drugs still have problems such as high toxicity, long treatment cycle, drug resistance and high price, so we still need to explore and develop a high efficiency and low toxicity drug. Poly(lactic-co-glycolic acid) (PLGA) refers to a nontoxic polymer compound that exhibits excellent biocompatibility. Traditional Chinese medicine (TCM) monomers come from natural plants, and have the characteristics of high efficiency and low toxicity. Applying PLGA to TCM monomers can make up for the defects of traditional dosage forms, improve bioavailability, reduce the frequency and dosage of drug use, and reduce toxicity and side effects, thus having the characteristics of sustained release and targeting. Accordingly, PLGA nanoparticles loaded with TCM monomers have been the focus of development. The previous research on drug loading advantages, preparation methods, and immune regulation of TCM PLGA nanoparticles is summarized in the following sections.

Lentinan-functionalized graphene oxide hydrogel as a sustained antigen delivery system for vaccines

Hydrogel has been proven to have the ability to deliver antigens continuously to achieve slow vaccine delivery, which makes it a promising candidate for an adjuvant delivery platform. Meanwhile, graphene oxide (GO) has garnered significant attention due to its good biosafety, excellent surface area and easy modification. However, GO exists as weak colloidal particles and poses challenges in self-assembling into a hydrogel structure. Here, we propose an innovative strategy involving self-assembling lentinan-functionalized graphene oxide hydrogel ((LNT-GO Gel) by simply mixing lentinan (LNT)-functionalized GO with polyethylene imide (PEI), which can simultaneously encapsulate antigens, achieve long-lasting release of antigens and generate excellent adjuvant activity. The results indicated that the LNT-GO Gel can control the release of OVA at the injection site and confer targeted delivering capacity to lymph nodes. And the date demonstrates that LNT-GO Gel displays favorable safety and biodegradability in vivo. Moreover, LNT-GO Gel can enhance the activation and maturation of dendritic cells (DCs) in lymph node, induce stronger OVA-specific antibody response, and promote spleen T lymphocyte differentiation, which underscores that LNT-GO Gel has ability to generate stronger antigen-specific humoral and cellular immune responses. Collectively, these results demonstrate the adjuvant potential of the lentinan-functionalized graphene oxide hydrogel (LNT-GO Gel) for subunit vaccine.

Structural characterization of chia seed polysaccharides and evaluation of its immunomodulatory and antioxidant activities

This study aims to extract an active heteropolysaccharide Chia seed polysaccharide (CSP-A) and further purified by DEAE Sepharose Fast Flow and Sepharose CL-6B chromatographic column, characterize its structure, and evaluate its antioxidant and immunomodulatory activities. Structural analysis revealed that CSP-A was composed of d-mannose, d-glucuronic acid and d-xylose in a molar ratio of 1:3:4 with molecular weight of 1.688 × 105 Da, owning 4 sugar residues of β-d-Manp-(1→, →4)-α-d-GlcpA-(1→, →2,4)-β-d-Xylp-(1→, and → 4)-β-d-Manp-(1 →. Congo red assay and microscopic characteristics showed that CSP-A in its solution may possess a helical conformation. In vitro experiments showed that CSP-A had moderate DPPH· and OH· scavenging activities. CSP-A also enhanced the phagocytosis ability of RAW 264.7 cells and prompted the release of NO, TNF-α, IL-6 and IL-1β from RAW 264.7 cells, which indicated CSP-A had immune regulation effect. This experiment provides scientific basis for further utilization and development of chia seeds, a kind of functional food.

Enhancement of the immune response via the facilitation of dendritic cell maturation by CD-205 Receptor-mediated Long-circling liposomes acting as an antigen and astragalus polysaccharide delivery system

CD-205 receptor-mediated dendritic cell (DC) targeting liposomes are commonly used as a delivery system for inducing a strong T-cell immune response or specific immune tolerance. This delivery system can carry both the antigen and adjuvant, thereby modulating DC maturation and also activating the T-cell response. In order to maximize the desired therapeutic effects of Astragalus polysaccharides (APS) and induce an efficient cellular and humoral immune response against the antigen, ovalbumin (OVA) and APS were encapsulated in long-circling liposomes conjugated with anti-CD-205 receptor antibodies to produce CD-205-targeted liposomes (iLPSM). We explored using a series of experiments evaluating the targeting efficiency of iLPSM. In vitro, iLPSM nanoparticles promoted the proliferation of macrophages, and the nanoparticles were rapidly phagocytized by macrophages. In vivo, iLPSM significantly improved the antibody titers of OVA-specific IgG and IgG, isotypes cytokine production, and T and B lymphocyte differentiation. Furthermore, iLPSM facilitated the maturation of DCs. In addition, iLPSM nanoparticles could prolong the retention time of nanoparticles at the injection site, leading to a strong, sustained immune response. These results show that the CD-205 antibody successfully binds to the corresponding cell receptor.

Selenium Nanoparticles Based on Morinda officinalis Polysaccharides: Characterization, Anti-Cancer Activities, and Immune-Enhancing Activities Evaluation In Vitro

Recently, selenium nanoparticles have been drawing attention worldwide, and it is crucial to increase the stability of nano-Se. Morinda officinalis polysaccharides (MOP) are the main active component in Morinda officinalis radix. However, their low activity has limited their application. A novel selenium nanoparticle (Se-MOP) was prepared to solve these problems using MOP as a dispersant. The zeta potential was measured to evaluate the stability, and UV and ATR-FTIR were used to investigate the binding type of selenium and MOP. The morphology was observed by the TEM method. Furthermore, the inhibitory effect on five selected cancer cells (HepG2, MCF-7, AGS, PC9, and HCT8) was evaluated, showing remarkable inhibition of all five cancer cells. The mechanism of inhibition was also investigated by cell circle assay, and it was found that Se-MOP could induce cell circle G0/G1 phase arrest. Immune-enhancing activities were evaluated by measuring the proliferation and cytokines of mouse spleen lymphocytes in vitro and quantitative RT-PCR. The results indicated that single stimulation of Se-MOP and synergistic stimulation with PHA or LPS increased immune capacity and improved immune by increasing the expression of cytokines.

The Therapeutic Potential of Plant Polysaccharides in Metabolic Diseases

Plant polysaccharides (PPS) composed of more than 10 monosaccharides show high safety and various pharmacological activities, including immunoregulatory, antitumor, antioxidative, antiaging, and other effects. In recent years, emerging evidence has indicated that many PPS are beneficial for metabolic diseases, such as cardiovascular disease (CVD), diabetes, obesity, and neurological diseases, which are usually caused by the metabolic disorder of fat, sugar, and protein. In this review, we introduce the common characteristics and functional activity of many representative PPS, emphasize the common risks and molecular mechanism of metabolic diseases, and discuss the pharmacological activity and mechanism of action of representative PPS obtained from plants including Aloe vera, Angelica sinensis, pumpkin, Lycium barbarum, Ginseng, Schisandra chinensis, Dioscorea pposite, Poria cocos, and tea in metabolic diseases. Finally, this review will provide directions and a reference for future research and for the development of PPS into potential drugs for the treatment of metabolic diseases.

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.

Chinese yam polysaccharides PLGA-stabilized Pickering emulsion as an adjuvant system for PCV- 2 vaccine to enhance immune response

Chinese yam polysaccharides (CYP) exhibit superior adjuvant activity and modulate the immune response, but the low bioavailability limits their clinical application. Pickering emulsions have been proven as an efficient vaccine delivery system to enhance the immune response. Here, we used the Chinese yam polysaccharides PLGA-stabilized Pickering emulsion adjuvant system (CYP-PPAS) loaded with Porcine circovirus 2 as a vaccine and focused on investigating its adjuvant activity on humoral and cellular immunity in mice. The CYP-PPAS increased PCV-2 antigen loading efficiency and showed a high antigen uptake efficiency by macrophages in vitro. In vivo, CYP-PPAS significantly facilitated DCs maturation in draining lymph nodes than CYP or PPAS alone group. The CYP-PPAS also induced an increased proliferation index and a CD4⁺/CD8⁺ ratio. Meanwhile, in contrast to the CYP and PPAS groups, CYP-PPAS elicited a stronger anti-PCV-2 IgG and mixed Th1/Th2 immune response. Specifically, the CYP-PPAS group displayed the high expression of CD107a, FasL, and Granzyme B secretion to augment a strong cytotoxic lymphocyte response. Overall, the CYP-PPAS was a successful adjuvant system for promoting humoral and cellular immune responses, which opens up an avenue for the development of effective adjuvants against infectious diseases.

Fabrication and characterization of Chinese yam polysaccharides PLGA nanoparticles stabilized Pickering emulsion as an efficient adjuvant

The Chinese yam polysaccharides PLGA nanoparticles were applied as stabilizers in this study to prepare O/W Pickering emulsion. The optimized preparation conditions were PLGA concentration of 5 mg/mL, ultrasonic power of 50 %, and ultrasonic time of 2 min. The CYP-PPAS emulsion exhibits a raspberry-like morphology with a large number of nanoparticles surrounding the oil droplets. The CYP-PPAS emulsion exhibited outstanding stability at 4 °C and 37 °C for 28 days with high antigen loading efficiency and provided a controlled and sustained release of Chinese yam polysaccharides and OVA antigen in vitro. CYP-PPAS/OVA elicited robust antigen-specific immune response and induced a mixed Th1/Th2 immune response after immunization. Furthermore, CYP-PPAS/OVA caused a high CD4+/CD8+ ratio leading in increased activation of splenic T lymphocytes subpopulations. Moreover, CYP-PPAS is a safe vaccination adjuvant with high safety profile in vivo. Thus, the novel designed Pickering emulsion CYP-PPAS was a safe and effective adjuvant for inducing the strong and long-term immune response.

Isolation, Characterization and Antioxidant Activity of Yam Polysaccharides

This study aimed to characterize the structure of Chinese yam (Dioscoreae Rhizoma) polysaccharide (CYP) and to investigate its protective effect against H₂O₂-induced oxidative damage in IEC-6 cells. The chemical composition and structural characteristics of the samples were analyzed by chemical and instrumental methods, including high-performance gel permeation chromatography, high-performance anion-exchange chromatography (HPAEC), Fourier transformed infrared (FT-IR), ultraviolet (UV), and scanning electron microscopy (SEM). Antioxidant activity was evaluated by establishing a cellular model of oxidative damage. The molecular weight of CYP was 20.89 kDa. Analysis of the monosaccharide composition revealed that CYP was primarily comprised of galactose (Gal), glucose (Glu), and galacturonic acid (GalA), and the ratio between them was 28.57:11.28:37.59. Pretreatment with CYP was able to improve cell viability, superoxide dismutase (SOD) activity, and reduce intracellular reactive oxygen species (ROS) production and malondialdehyde (MDA) content after H₂O₂ injury. CYP also attenuated oxidative damage in cells through the mitogen-activated protein kinase (MAPK) signaling pathway. This study showed that CYP was an acidic heteropolysaccharide with a good protective effect against oxidative damage, and it thus has good prospects in food and biopharmaceutical industries.

Effects of the polysaccharides extracted from Chinese yam (Dioscorea opposita Thunb.) on cancer-related fatigue in mice

The aim of this study was to investigate the anti-fatigue activity of Chinese Yam polysaccharides (CYPs). The structural characterization of CYPs was conducted using Fourier transform-infrared spectroscopy, nuclear magnetic resonance spectroscopy, gel permeation chromatography-light scattering-refractive index, and ion chromatography. The weight-loaded swimming capability, behavior performance, tumor growth, content of adenosine triphosphate (ATP), and biochemical markers of CYP in a cancer-related fatigue mouse model were tested. The results showed that CYP is a mixture with an average M_w of 75.57 kDa and is mainly composed of rhamnose, glucuronic acid, glucose, galactose, and arabinose with a molar ratio of 0.01 : 0.06 : 1.00 : 0.17 : 0.01. CYP increased the exhausting swimming time, which was decreased in the cisplatin (DDP) control group and the model group. CYP also increased the content of ATP in musculus gastrocnemius, which was down-regulated by DDP; the DDP had significantly enhanced the contents of interleukin-1β (IL-lβ), malondialdehyde (MDA), blood urea nitrogen (BUN) and lactic dehydrogenase (LDH) and inhibited the activity of superoxide dismutase (SOD) in the muscle. Administration of CYP decreased the levels of IL-lβ, MDA, BUN and LDH, and up-regulated the SOD activity. The DDP + CYP group presented a decreased tumor volume and a lower tumor weight as compared with the model group. Moreover, the mice in the CYP or DDP + CYP groups had heavier body weights than the mice in the model group and DDP group. These results suggest that CYP should improve cancer-related fatigue via the regulation of inflammatory responses, oxidative stress and increase in energy supplementation.

Preparation of Amomum longiligulare polysaccharides 1- PLGA nanoparticle and its immune enhancement ability on RAW264.7 cells

Amomum longiligulare polysaccharides 1 (ALP1) was a glucosan that possessed an immune enhancement ability. However, disadvantages including short biological half-life hindered the application of ALP1. To solve these shortcomings, ALP1 was successfully prepared to nanoparticles (ALPP) with poly (lactic-co-glycolic acid) in the present study. And the optimal preparation conditions were developed by using the response surface method with a Box-Behnken design. The results showed that the encapsulation efficiency of ALPP reached a high level (79.88%) when the volume ratio of the water phase to the organic phase was 1:7, the volume ratio of the primary emulsion to the external water phase was 1:7, and the concentration of F68 was 0.7%. ALPP showed a controlled and sustained release. Meanwhile, the scanning electron microscope results showed that ALPP was a kind of nanoparticles with a diameter of 389.77 nm. In addition, the activating effect of ALPP on macrophages was studied. The results indicated that ALPP showed a better activity on promoting the RAW264.7 cells' activities and polarizing RAW264.7 cells into both M1 type and M2 type macrophages, compared to ALP1.

Mannose-Modified Chitosan Poly(lactic-co-glycolic acid) Microspheres Act as a Mannose Receptor-Mediated Delivery System Enhancing the Immune Response

The mannose receptor (MAN-R)-targeted delivery system is commonly used to deliver antigens to macrophages or immature dendritic cells (DCs) to promote the efficiency of antigen presentation. To maximize the enhancement effects of chitosan (CS) and induce an efficient humoral and cellular immune response against an antigen, we encapsulated ovalbumin (OVA) in poly(lactic-co-glycolic acid) (PLGA) microspheres (MPs) and conjugated it with MAN-modified CS to obtain MAN-R-targeting nano-MPs (MAN-CS-OVA-PLGA-MPs). The physicochemical properties, drug loading rate, and immunomodulation activity of MAN-CS-OVA-PLGA-MPs were evaluated. In vitro, MAN-CS-OVA-PLGA-MPs (80 μg mL⁻¹) could enhance the proliferation of DCs and increase their phagocytic efficiency. In vivo, MAN-CS-OVA-PLGA-MPs significantly increased the ratio of CD3⁺CD4⁺/CD3⁺CD8⁺ T cells, increased CD80⁺, CD86⁺, and MHC II expression in DCs, and improved OVA-specific IgG, IgG1, IgG2a, and IgG2b antibodies. Moreover, MAN-CS-OVA-PLGA-MPs promoted cytokine (IFN-γ, IL-4, and IL-6) production in mice. Taken together, our results show that MAN-CS-OVA-PLGA-MPs may act by activating the T cells to initiate an immune response by promoting the maturation of dendritic cells and improving their antigen presentation efficiency. The current study provides a basis for the use of MAN-CS-OVA-PLGA-MPs as an antigen and adjuvant delivery system targeting the MAN-R on the surface of macrophages and dendritic cells.

Characterization of the complete chloroplast genome of Dioscorea polystachya Turcz

Dioscorea polystachya Turcz. is an important Chinese herbal medicine and the raw material of the medicine ingrediente (Chinese yam polysaccharide). It belongs to Dioscorea, which has 60 species and distribute in middle and southeast of China. In this study, we sequenced the sample of D. polystachya based on Jiaozuo, Henan and determined its complete chloroplast genome. The length of cp genome was 152,958 bp, includes two invert repeats (IR) regions of 25,492 bp, a large single-copy (LSC) region of 83,152 bp, and a short single-copy (SSC) region of 18,822 bp. There were 131 genes, which included 85 protein coding genes, 8 rRNA, and 38 tRNA, and overall GC content covered by 37.1%. Each of trnK-UUU, rps16, trnG-UCC, atpF, rpoC1, trnL-UAA, trnV-UAC, petB, petD, rpl16, rpl2, ndhB, trnI-GAU, trnA-UGC, and ndhA genes contained an intron, clpP and ycf3 contained 2 introns. The phylogenetic position showed that D. Polystachya had the closest relationship with Dioscorea alata (MG267382) and Dioscorea aspersa (NC039807).

Nanoparticles of Chitosan/Poly(D,L-Lactide-Co-Glycolide) Enhanced the Immune Responses of Haemonchus contortus HCA59 Antigen in Model Mice

Background

Hepatocellular carcinoma-associated antigen 59 (HCA59) from excretory/secretory products of Haemonchus contortus is known to have the ability to modulate the functions of host cells. However, its immunogenicities using different nanoparticles adjuvants remain poorly understood.

Purpose

The study aimed to select an efficient nanoparticle antigen delivery system, which could enhance the immune responses of Haemonchus contortus HCA59 in mice.

Methods

Here, the immune responses induced by the recombinant protein of HCA59 (rHCA59) with poly-D,L-lactide-co-glycolide (PLGA) nanoparticles, Chitosan nanoparticles, mixture of PLGA and Chitosan nanoparticles (rHCA59-Chitosan-PLGA), and Freund’s complete adjuvant were observed, respectively, in mice. Cytokine and antibody levels induced by different groups were detected by ELISA assay. The effects of lymphocyte proliferations on different groups were examined using CCK-8 kit. Phenotypes of T cells and dendritic cells were analyzed by flow cytometry.

Results

On day 14 post vaccination, levels of IgM, IgG1, IgG2a, IFN-γ, IL-4, and IL-17 were significantly increased in the groups immunized with rHCA59 encapsulated with nanoparticles. After mice were vaccinated with rHCA59 loaded with Chitosan/PLGA nanoparticles, lymphocytes proliferated significantly. Additionally, the percentages of CD4⁺ T cells (CD3⁺ CD4⁺), CD8⁺ T cells (CD3⁺ CD8⁺), and dendritic cells (CD11c⁺ CD83⁺, CD11c⁺ CD86⁺) were obviously up-regulated in the mice immunized with nanoparticles, especially in the rHCA59-Chitosan-PLGA antigen delivery system group.

Conclusion

The findings of this research demonstrated that rHCA59-Chitosan-PLGA antigen delivery system could induce higher immune responses in mice model and indicated that rHCA59 might be a good candidate molecule to develop nanovaccines against Haemonchus contortus in future study.

The Immunoenhancement Effects of Polyethylenimine-Modified Chinese Yam Polysaccharide-Encapsulated PLGA Nanoparticles as an Adjuvant

Background

Poly(lactic-co-glycolic acid) (PLGA) has been extensively applied for sustained drug delivery and vaccine delivery system. However, vaccines delivered by PLGA nanoparticles alone could not effectively activate antigen-presenting cells (APCs) to induce strong immune responses.

Purpose

The aim of the present study was to design polyethylenimine (PEI)-modified Chinese yam polysaccharide (CYP)-encapsulated PLGA nanoparticles (CYPP-PEI) as a vaccine delivery system and evaluate the adjuvant activities in vitro and in vivo.

Materials and Methods

Cationic-modified nanoparticles exhibited high antigen absorption and could be efficiently taken by APCs to enhance the immune responses. Therefore, PEI-modified CYP-encapsulated PLGA nanoparticles (CYPP-PEI) were prepared. The storage stability and effective adsorption capacity for porcine circovirus-2 (PCV-2) antigen of these antigen-absorbed nanoparticles were measured for one month. Furthermore, the adjuvant activity of CYPP-PEI nanoparticles was evaluated on macrophages in vitro and through immune responses triggered by PCV-2 antigen in vivo.

Results

The PCV-2 absorbed CYPP-PEI nanoparticles showed excellent storage stability and high absorption efficiency of PCV-2 antigen. In vitro, CYPP-PEI nanoparticles promoted antigen uptake, enhanced surface molecular expressions of CD80 and CD86, and improved cytokine secretion of TNF-α, IFN-γ, and IL-12p70 in macrophages. After immunization with CYPP-PEI/PCV-2 formulation in mice, the expressions of surface activation markers on dendritic cells which located in draining lymph nodes were increased, such as MHCI, MHCII, and CD80. In addition, CYPP-PEI nanoparticles induced dramatically high PCV-2-specific IgG levels which could last for a long time and stimulated the secretion of subtype antibodies and cytokines. The results showed that CYPP-PEI could induce Th1/Th2 mixed but Th1-biased type immune responses.

Conclusion

Polyethylenimine-modified Chinese yam polysaccharide-encapsulated PLGA nanoparticle was a potential vaccine delivery system to trigger strong and persistent immune responses.

The important role of polysaccharides from a traditional Chinese medicine-Lung Cleansing and Detoxifying Decoction against the COVID-19 pandemic

The new coronavirus pneumonia, named COVID-19 by the World Health Organization, has become a pandemic. It is highly pathogenic and reproduces quickly. There are currently no specific drugs to prevent the reproduction and spread of COVID-19. Some traditional Chinese medicines, especially the Lung Cleansing and Detoxifying Decoction (Qing Fei Pai Du Tang), have shown therapeutic effects on mild and ordinary COVID-19 patients. Polysaccharides are important ingredients in this decoction. This review summarizes the potential pharmacological activities of polysaccharides isolated by hot water extraction from Lung Cleansing and Detoxifying Decoction, which is consistent with its production method, to provide the theoretical basis for ongoing research on its application.

The structural characterization and immune modulation activitives comparison of Codonopsis pilosula polysaccharide (CPPS) and selenizing CPPS (sCPPS) on mouse in vitro and vivo

Codonopsis pilosula polysaccharide (CPPS) and selenizing CPPS (sCPPS) were prepared and identified by a combination of chemical and instrumental analysis. Their immune modulation activities were compared by lymphocyte proliferation and flowcytometry tests in vitro or serum antibody responses and cytokines with immunization against OVA mice in vivo. The results showed that the sCPPS was successfully modified in selenylation. In vitro, the sCPPS were more effective compared with CPPS in promoting lymphocyte proliferation synergistically with PHA or LPS and increasing the ratio of CD4+ to CD8 + T cells. In vivo, sCPPS could significantly raised IgG, IgM, IFN-γ, IL-2 and IL-4 contents in the serum of mouse against OVA in comparison with CPPS. These results indicate that selenylation modification can enhance the immune modulation activitives of CPPS. sCPPS would be as a component drug of new-type immunoenhancer.

Encapsulation of Red Propolis in Polymer Nanoparticles for the Destruction of Pathogenic Biofilms

Microbial biofilms, structured communities of microorganisms, have been often associated to the infection and bacterial multiresistance problem. Conventional treatment of infection involves the use of antibiotics, being an alternative approach is the use of red propolis, a natural product, to prepare polymer nanoparticles. The aim of the present study was to encapsulate red propolis extract in poly(lactic-co-glycolic acid) (PLGA) nanoparticles for destruction in vitro of pathogenic biofilms. Poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs) containing red propolis hydroethanolic extract (2 mg/mL) were produced by emulsification solvent diffusion method. The extract and developed nanoparticles were analyzed for antimicrobial activity and inhibition of bacterial biofilm formation in vitro against Staphylococcus aureus and Pseudomonas aeruginosa. Transmission electron microscopy images confirmed spherical nanoparticles in the range size from 42.4 nm (PLGA NPs) to 69.2 nm (HERP PLGA NPs), with encapsulation efficiencies of 96.99%. The free extract and encapsulated in polymer nanoparticle presented antimicrobial potential, with a minimum inhibitory concentration from 15.6 to 125 μg mL^-1 and from 100 to 1560 μg mL^-1 to inhibit biofilm formation for the Staphylococcus aureus and Pseudomonas aeruginosa, respectively.

Designing selenium polysaccharides-based nanoparticles to improve immune activity of Hericium erinaceus

In previous researches, the results showed that selenium Hericium erinaceus polysaccharide and Hericium erinaceus polysaccharide-loaded poly (lactic-co-glycolic acid) nanoparticles enhanced immune responses. In order to further enhance the immune adjuvant activity and phagocytosis of the nanoparticles, two way of combination (selenium-HEP loaded PLGA nanoparticles and selenium modified HEP-PLGA nanoparticles) were prepared to investigate the effects on macrophages in vitro. After treatment with the nanoparticles, the effects of phagocytosis, co-stimulatory molecules expression, nitric oxide (NO), and cytokines secretion were evaluated. The results showed that the particle size, PDI and zeta potential of the selenium-HEP loaded PLGA nanoparticles (Se-HEP-PLGA) and selenium modifified HEP-PLGA nanoparticles (HEP-PLGA-Se) were presented. Se-HEP-PLGA and HEP-PLGA-Se nanoparticles significantly stimulated phagocytic activity, CD40 and CD86 expression of macrophages. In addition, the levels of NO, TNF-α, IL-1β and IL-6 were enhanced in the peritoneal macrophages by stimulation with Se-HEP-PLGA and HEP-PLGA-Se nanoparticles. Among them, Se-HEP-PLGA showed the best effects on the expression of co-stimulatory molecules, secretions of NO and cytokines. These results indicated that Se-HEP-PLGA could enhance the activation of macrophages, and it could be potentially used as an HEP delivery system for the induction of strong immune responses.

Recent progress in the research of yam mucilage polysaccharides: Isolation, structure and bioactivities

Yam (Dioscorea spp.), known as an edible and medicinal tuber crop in China, has been used historically for the treatment of diabetes, diarrhea, asthma, and other ailments in traditional Chinese medicine. Moreover, it has been consumed as starchy food for thousands of years in China. Modern phytochemistry and pharmacological experiments have been proved that non-starch polysaccharide is one of the main bioactive substances of yam. Many studies have been focused on the isolation and identification of polysaccharides and their bioactivities of Chinese yam. However, due to the difference in the variety of raw materials and the method of polysaccharides extracting, the structure and biological activity of the obtained polysaccharides also differ. It has been demonstrated that Chinese yam polysaccharide has various important biological activities, such as hypoglycemia, immunomodulatory, antioxidant, and antitumor activities. This paper is aimed at summarizing previous and current references of the isolation processes, structural features and bioactivities of yam polysaccharides. The review will serve as a useful reference material for further investigation and application of yam polysaccharides in functional foods and medicine fields.

Chinese yam (Dioscorea opposita Thunb.) alleviates antibiotic-associated diarrhea, modifies intestinal microbiota, and increases the level of short-chain fatty acids in mice

Antibiotic-associated diarrhea (AAD) is a common adverse effect of antibiotic treatment. The study was to evaluate effects of Chinese yam (Dioscorea opposita Thunb.) on AAD, and changes of intestinal microbiota and short-chain fatty acids (SCFA). AAD model was established using Balb/c mice by gavage with ampicillin for 5 days, followed by a 10-day administration of low, medium, and high dosage of Chinese yam, containing allantoin (4.35 mg/g) and polysaccharides (85.51 mg/g). The results showed that Chinese yam accelerated the recovery from acute diarrhea, reverse AAD-induced body weight loss and cecal enlargement. The high-dosage Chinese yam increased probiotic Bifidobacteria and Lactobacilli by 47% and 21% and decreased potential pathogen Enterococcus and Clostridium perfringens by 8% and 27% on day 15 (P < .05). Bacterial community analysis revealed that Chinese yam contributed to repair the ampicillin-induced intestinal microbiota disorder, enrich the abundance of Bacteroides spp. and Clostridium spp. Additionally, Chinese yam supplementation increased the production of SCFA.

Lipid Nanoparticles-Encapsulated YF4: A Potential Therapeutic Oral Peptide Delivery System for Hypertension Treatment

Drugs are administered orally in the clinical treatment of hypertension. Antihypertensive peptides have excellent angiotensin converting enzyme inhibitors activity in vitro. However, the poor oral bioavailability and therapeutic effect of antihypertensive peptides were mainly caused by rapid degradation in gastrointestinal and the short circulation time in blood, which remain to be further optimized. Therefore, the novel oral peptide delivery system is urged to improve the oral absorption and efficacy of peptide drugs. In this work, Tyr-Gly-Leu-Phe (YF4)-loaded lipid nanoparticles (YF4-LNPs) combined the advantages of polymer nanoparticles and liposomes were developed, which could greatly enhance the oral bioavailability and ameliorate the sustained release of peptide drug. YF4 loaded nanoparticles (YF4-NPs) were firstly prepared by a double-emulsion internal phase/organic phase/external phase (W1/O/W2) solvent evaporation method. YF4-NPs were further coated by membrane hydration-ultrasonic dispersion method to obtain the YF4-LNPs. The optimal YF4-LNPs showed a small particle size of 227.3 ± 3.8 nm, zeta potential of -7.27 ± 0.85 mV and high entrapment efficiency of 90.28 ± 1.23%. Transmission electronic microscopy analysis showed that the core-shell lipid nanoparticles were spherical shapes with an apparent lipid bilayer on the surface. Differential scanning calorimetry further proved that YF4 was successfully entrapped into YF4-LNPs. The optimal preparation of YF4-LNPs exhibited sustained release of YF4 in vitro and a 5 days long-term antihypertensive effect in vivo. In summary, the lipid nanoparticles for oral antihypertensive peptide delivery were successfully constructed, which might have a promising future for hypertension treatment.

pH-responsive Astragalus polysaccharides-loaded poly(lactic-co-glycolic acid) nanoparticles and their in vitro immunogenicity

Astragalus polysaccharides (APS) have long been well known as immune boosters, but have not been fully exploited in clinical settings. Here, poly(lactic-co-glycolic acid) (PLGA) was used to form a nanocarrier for APS to enhance its bioavailability. The aim was to improve the immunoadjuvanticity of conventional APS-loaded PLGA-based nanoparticles (NPs), referred to as APSPs, and to optimize the synthesis parameters to maximize the encapsulation efficiency (EE). As slow drug release can cause insufficient immune responses, ammonium bicarbonate was used to produce pH-responsive APSPs. The optimum parameters for maximizing EE (mean maximum experimental EE: 65.23 ± 0.51%) were an oil phase (O)/internal aqueous phase (W₁) ratio of 7:1, an external aqueous phase (W₂)/preliminary emulsion (PE) ratio of 5:1, and a Pluronic F-68 concentration of 1.1%. Moreover, the pH-responsive APSPs had low cytotoxicity and significantly enhanced mice splenic lymphocyte proliferation. The increased T-cell CD4⁺/CD8⁺ ratio after pH-responsive APSP treatment of mice splenic lymphocytes compared with free APS, blank PLGA NP, and conventional APSP treatment demonstrated its excellent immunoadjuvanticity. This study provides abundant evidence that these novel PLGA-based pH-responsive NPs enhanced the immunoadjuvanticity of APS. Furthermore, pH-responsive APSPs synthesized using the optimum parameters exhibited long-term stability in normal storage conditions, suggesting suitability for clinical application.

Drug delivery for bioactive polysaccharides to improve their drug-like properties and curative efficacy

Over several decades, natural polysaccharides (PSs) have been actively exploited for their wide bioactivities. So far, many PS-related reviews have been published; however, none focused on the delivery of bioactive PSs as therapeutic molecules. Herein, we summarized and discussed general pharmacokinetic properties of PSs and drug delivery systems (DDSs) developed for them, together with the challenges and prospects. Overall, most bioactive PSs suffer from undesirable pharmacokinetic attributes, which negatively affect their efficacy and clinical use. Various DDSs therefore have been being utilized to improve the drug-like properties and curative efficacy of bioactive PSs by means of improving oral absorption, controlling the release, enhancing the in vivo retention ability, targeting the delivery, exerting synergistic effects, and so on. Specifically, nano-sized insoluble DDSs were mainly applied to improve the oral absorption and target delivery of PSs, among which liposome was especially suitable for immunoregulatory and/or anti-ischemic PSs due to its synergistic effects in immunoregulation and biomembrane repair. Chemical conjugation of PSs was mainly utilized to improve their oral absorption and/or prolong their blood residence. With formulation flexibility, in situ forming systems alone or in combination with drug conjugation could be used to achieve day(s)- or month(s)-long sustained delivery of PSs per dosing.

Exploring the immunopotentiation of Chinese yam polysaccharide poly(lactic-co-glycolic acid) nanoparticles in an ovalbumin vaccine formulation in vivo

Biocompatible and biodegradable poly(lactic-co-glycolic acid) (PLGA) has been approved by the US Food and Drug Administration and has frequently been used to develop potential vaccine delivery systems. The immunoregulation and immunopotentiation of Chinese yam polysaccharide (CYP) have been widely demonstrated. In the current study, cell uptake mechanisms in dendritic cells (DCs) were monitored in vitro using confocal laser scanning microscopy, transmission electron microscopy, and flow cytometry. To study a CYP-PLGA nanoparticle-adjuvanted delivery system, CYP and ovalbumin (OVA) were encapsulated in PLGA nanoparticles (CYPPs) to act as a vaccine, and the formulation was tested in immunized mice. The CYPPs more easily underwent uptake by DCs in vitro, and CYPP/OVA could stimulate more effective antigen-specific immune responses than any of the single-component formulations in vivo. Mice immunized using CYPP/OVA exhibited more secretion of OVA-specific IgG antibodies, better proliferation, and higher cytokine secretion by splenocytes and significant activation of CD3+CD4+ and CD3+CD8+ T cells. Overall, the CYPP/OVA formulation produced a stronger humoral and cellular immune response and a mixed Th1/Th2 immune response with a greater Th1 bias in comparison with the other formulations. In conclusion, the data demonstrate that the CYPP-adjuvanted delivery system has the potential to strengthen immune responses and lay the foundation for novel adjuvant design.

Enhanced and Extended Anti-Hypertensive Effect of VP5 Nanoparticles

Hypertension has become a significant global public health concern and is also one of the most common risk factors of cardiovascular disease. Recent studies have shown the promising result of peptides inhibiting angiotensin converting enzyme (ACE) in lowering the blood pressure in both animal models and humans. However, the oral bioavailability and continuous antihypertensive effectiveness require further optimization. Novel nanoparticle-based drug delivery systems are helpful to overcome these barriers. Therefore, a poly-(lactic-co-glycolic) acid nanoparticle (PLGANPs) oral delivery system, of the antihypertensive small peptides Val-Leu-Pro-Val-Pro (VLPVP, VP5) model, was developed in this study and its antihypertensive effect was investigated in spontaneously hypertensive rats (SHRs) for the first time. The obtained VP5 nanoparticles (VP5-NPs) showed a small particle size of 223.7 ± 2.3 nm and high entrapment efficiency (EE%) of 87.37% ± 0.92%. Transmission electronic microscopy (TEM) analysis showed that the nanoparticles were spherical and homogeneous. The optimal preparation of VP5-NPs exhibited sustained release of VP5 in vitro and a 96 h long-term antihypertensive effect with enhanced efficacy in vivo. This study illustrated that PLGANPs might be an optimal formulation for oral delivery of antihypertensive small peptides and VP5-NPs might be worthy of further development and use as a potential therapeutic strategy for hypertension in the future.