PLGA nanoparticles loaded with beta-lactoglobulin-derived peptides modulate mucosal immunity and may facilitate cow's milk allergy prevention

Research Progress of Oral Immune Tolerance Mechanism Induced by Whey Protein

Cow milk allergy (CMA) is prevalently observed among infants and young children, exerting adverse effects on their growth and quality of life. Oral immune tolerance (OIT) is a more effective method for the prevention and treatment of CMA. The site of OIT is mainly in the gastrointestinal tract, so this article reviews the composition and structural characteristics of intestinal immune system, the molecular mechanisms of immune tolerance by regulatory T cells (Treg), dendritic cells, and gut microbiota. In addition, this paper summarizes the research progress of T cell epitope peptides of β-lactoglobulin and α-lactalbumin in whey protein hydrolysates. The mechanism of OIT induced by whey protein hydrolysate or whey protein combined with other anti-allergic components (phenolic compounds, probiotics, etc.) is overviewed to provide new ideas for the development of hypoallergenic infant formula.

Molecular Allergology: Epitope Discovery and Its Application for Allergen-Specific Immunotherapy of Food Allergy

The prevalence of food allergy continues to rise, posing a significant burden on health and quality of life. Research on antigenic epitope identification and hypoallergenic agent design is advancing allergen-specific immunotherapy (AIT). This review focuses on food allergens from the perspective of molecular allergology, provides an overview of integration of bioinformatics and experimental validation for epitope identification, highlights hypoallergenic agents designed based on epitope information, and offers a valuable guidance to the application of hypoallergenic agents in AIT. With the development of molecular allergology, the characterization of the amino acid sequence and structure of the allergen at the molecular level facilitates T-/B-cell epitope identification. Alignment of the identified epitopes in food allergens revealed that the amino acid sequence of T-/B-cell epitopes barely overlapped, providing crucial data to design allergen molecules as a promising form for treating (FA) food allergy. Manipulating antigenic epitopes can reduce the allergenicity of allergens to obtain hypoallergenic agents, thereby minimizing the severe side effects associated with AIT. Currently, hypoallergenic agents are mainly developed through synthetic epitope peptides, genetic engineering, or food processing methods based on the identified epitope. New strategies such as DNA vaccines, signaling molecules coupling, and nanoparticles are emerging to improve efficiency. Although significant progress has been made in designing hypoallergenic agents for AIT, the challenge in clinical translation is to determine the appropriate dose and duration of treatment to induce long-term immune tolerance.

Recent Advances in Peptide-Loaded PLGA Nanocarriers for Drug Delivery and Regenerative Medicine

Peptide-loaded poly(lactide-co-glycolide) (PLGA) nanocarriers represent a transformative approach to addressing the challenges of peptide-based therapies. These systems offer solutions to peptide instability, enzymatic degradation, and limited bioavailability by providing controlled release, targeted delivery, and improved stability. The versatility of PLGA nanocarriers extends across therapeutic domains, including cancer therapy, neurodegenerative diseases, vaccine development, and regenerative medicine. Innovations in polymer chemistry, surface functionalization, and advanced manufacturing techniques, such as microfluidics and electrospraying, have further enhanced the efficacy and scalability of these systems. This review highlights the key physicochemical properties, preparation strategies, and proven benefits of peptide-loaded PLGA systems, emphasizing their role in sustained drug release, immune activation, and tissue regeneration. Despite remarkable progress, challenges such as production scalability, cost, and regulatory hurdles remain.

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.

Application of Nanoparticles for Immunotherapy of Allergic Rhinitis

Allergen Immunotherapy (AIT) is the only etiological therapeutic method available for allergic rhinitis (AR). Currently, several options for AIT in the market, such as subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT), have different routes of administration. These traditional methods have achieved encouraging outcomes in clinic. However, the side effects associated with these methods have raised the need for innovative approaches for AIT that improve safety, shorten the course of treatment and increase local drug concentration. Nanoparticles (NPs) are particles ranging in size from 1 to 100 nm, which have been hired as potential adjuvants for AIT. NPs can be employed as agents for modulating immune responses in AR or/and carriers for loading proteins, peptides or DNA molecules. This review focuses on different kinds of nanoparticle delivery systems, including chitosan nanoparticles, exosomes, metal nanoparticles, and viral nanoparticles. We summarized the advantages and limitations of NPs for the treatment of allergic rhinitis. Overall, NPs are expected to be a therapeutic option for AR, which requires more in-depth studies and long-term therapeutic validation.

Liver-Targeting Nanoplatforms for the Induction of Immune Tolerance

Liver-targeting nanoparticles have emerged as a promising platform for the induction of immune tolerance by taking advantage of the liver's unique tolerogenic properties and nanoparticles' physicochemical flexibility. Such an approach provides a versatile solution to the treatment of a diversity of immunologic diseases. In this review, we begin by assessing the design parameters integral to cell-specific targeting and the tolerogenic induction of nanoplatforms engineered to target the four critical immunogenic hepatic cells, including liver sinusoidal epithelial cells (LSECs), Kupffer cells (KCs), hepatic stellate cells (HSCs), and hepatocytes. We also include an overview of multiple therapeutic strategies in which nanoparticles are being studied to treat many allergies and autoimmune disorders. Finally, we explore the challenges of using nanoparticles in this field while highlighting future avenues to expand the therapeutic utility of liver-targeting nanoparticles in autoimmune processes.

A novel peanut allergy immunotherapy: Plant-based enveloped Ara h 2 Bioparticles activate dendritic cells and polarize T cell responses to Th1

Introduction

As the only market-authorized allergen immunotherapy (AIT) for peanut allergy is accompanied by a high risk of side effects and mainly induces robust desensitization without sustained efficacy, novel treatment options are required. Peanut-specific plant-derived eBioparticles (eBPs) surface expressing Ara h 2 at high density have been shown to be very hypoallergenic. Here, we assessed the dendritic cell (DC)-activating and T cell polarization capacity of these peanut-specific eBPs.

Methods

Route and kinetics of eBP uptake were studied by (imaging) flow cytometry using monocyte-derived DCs incubated with fluorescently-labelled Ara h 2 eBPs or natural Ara h 2 (nAra h 2) in the presence or absence of inhibitors that block pathways involved in macropinocytosis, phagocytosis, and/or receptor-mediated uptake. DC activation was monitored by flow cytometry (maturation marker expression) and ELISA (cytokine production). T cell polarization was assessed by co-culturing DCs exposed to Ara h 2 eBPs or nAra h 2 with naïve CD4+ T cells, followed by flow cytometry assessment of intracellular IFNγ+ (Th1) and IL-13+ (Th2), and CD25+CD127-Foxp3+ regulatory T cells (Tregs). The suppressive activity of Tregs was tested using a suppressor assay.

Results

Ara h 2 eBPs were taken up by DCs through actin-dependent pathways. They activated DCs demonstrated by an induced expression of CD83 and CD86, and production of TNFα, IL-6, and IL-10. eBP-treated DCs polarized naïve CD4+ T cells towards Th1 cells, while reducing Th2 cell development. Furthermore, eBP-treated DCs induced reduced the frequency of Foxp3+ Tregs but did not significantly affect T cell IL-10 production or T cells with suppressive capacity. In contrast, DC activation and Th1 cell polarization were not observed for nAra h 2.

Conclusion

Ara h 2 eBPs activate DCs that subsequently promote Th1 cell polarization and reduce Th2 cell polarization. These characteristics mark Ara h 2 eBPs as a promising novel candidate for peanut AIT.

Live Cell Imaging by Förster Resonance Energy Transfer Fluorescence to Study Trafficking of PLGA Nanoparticles and the Release of a Loaded Peptide in Dendritic Cells

Our previous study demonstrated that a selected β-lactoglobulin-derived peptide (BLG-Pep) loaded in poly(lactic-co-glycolic acid) (PLGA) nanoparticles protected mice against cow's milk allergy development. However, the mechanism(s) responsible for the interaction of the peptide-loaded PLGA nanoparticles with dendritic cells (DCs) and their intracellular fate was/were elusive. Förster resonance energy transfer (FRET), a distance-dependent non-radioactive energy transfer process mediated from a donor to an acceptor fluorochrome, was used to investigate these processes. The ratio of the donor (Cyanine-3)-conjugated peptide and acceptor (Cyanine-5) labeled PLGA nanocarrier was fine-tuned for optimal (87%) FRET efficiency. The colloidal stability and FRET emission of prepared NPs were maintained upon 144 h incubation in PBS buffer and 6 h incubation in biorelevant simulated gastric fluid at 37 °C. A total of 73% of Pep-Cy3 NP was internalized by DCs as quantified using flow cytometry and confirmed using confocal fluorescence microscopy. By real-time monitoring of the change in the FRET signal of the internalized peptide-loaded nanoparticles, we observed prolonged retention (for 96 h) of the nanoparticles-encapsulated peptide as compared to 24 h retention of the free peptide in the DCs. The prolonged retention and intracellular antigen release of the BLG-Pep loaded in PLGA nanoparticles in murine DCs might facilitate antigen-specific tolerance induction.

PLGA Particles in Immunotherapy

Poly(lactic-co-glycolic acid) (PLGA) particles are a widely used and extensively studied drug delivery system. The favorable properties of PLGA such as good bioavailability, controlled release, and an excellent safety profile due to the biodegradable polymer backbone qualified PLGA particles for approval by the authorities for the application as a drug delivery platform in humas. In recent years, immunotherapy has been established as a potent treatment option for a variety of diseases. However, immunomodulating drugs rely on targeted delivery to specific immune cell subsets and are often rapidly eliminated from the system. Loading of PLGA particles with drugs for immunotherapy can protect the therapeutic compounds from premature degradation, direct the drug delivery to specific tissues or cells, and ensure sustained and controlled drug release. These properties present PLGA particles as an ideal platform for immunotherapy. Here, we review recent advances of particulate PLGA delivery systems in the application for immunotherapy in the fields of allergy, autoimmunity, infectious diseases, and cancer.

Preparation, Identification and Application of β-Lactoglobulin Hydrolysates with Oral Immune Tolerance

To reveal, for the first time, the mechanism of T cell epitope release from β-lactoglobulin that induces oral immune tolerance, a strategy for the prediction, preparation, identification and application of β-lactoglobulin hydrolysate with oral immune tolerance was established using the bioinformatics method, hydrolysis, mass spectrometry, T cell proliferation assays and animal experiments. Some T cell epitope peptides of β-lactoglobulin were identified for the first time. The hydrolysates of trypsin, protamex and papain showed oral tolerance, among which the hydrolysates of protamex and papain have been reported for the first time. Although the neutral protease hydrolysate contained T cell epitopes, it still had allergenicity. The mechanism behind oral immune tolerance induction by T cell epitopes needs to be further revealed. In addition, the trypsin hydrolysate with abundant T cell epitopes was added to whey protein to prepare the product for oral immune tolerance. Overall, this study provides insights into the development of new anti-allergic milk-based products and their application in the clinical treatment of milk allergies.

Oral pretreatment with β-lactoglobulin derived peptide and CpG co-encapsulated in PLGA nanoparticles prior to sensitizations attenuates cow's milk allergy development in mice

Cow's milk allergy is a common food allergy among infants. Improved hygiene conditions and loss of microbial diversity are associated with increased risk of allergy development. The intestinal immune system is essential for oral tolerance induction. In this respect, bacterial CpG DNA is known to drive Th1 and regulatory T-cell (Treg) development via Toll-Like-Receptor 9 (TLR-9) signaling, skewing away from the allergic Th2 phenotype. We aimed to induce allergen specific tolerance via oral delivery of poly (lactic-co-glycolic acid) nanoparticles (NP) co-encapsulated with a selected β-lactoglobulin derived peptide (BLG-Pep) and TLR-9 ligand CpG oligodeoxynucleotide (CpG). In vivo, 3-4-week-old female C3H/HeOuJ mice housed in individually ventilated cages received 6-consecutive-daily gavages of either PBS, whey, BLG-Pep/NP, CpG/NP, a mixture of BLG-Pep/NP plus CpG/NP or co-encapsulated BLG-Pep+CpG/NP, before 5-weekly oral sensitizations with whey plus cholera toxin (CT) or only CT (sham) and were challenged with whey 5 days after the last sensitization. The co-encapsulated BLG-Pep+CpG/NP pretreatment, but not BLG-Pep/NP, CpG/NP or the mixture of BLG-Pep/NP plus CpG/NP, prevented the whey-induced allergic skin reactivity and prevented rise in serum BLG-specific IgE compared to whey-sensitized mice. Importantly, co-encapsulated BLG-Pep+CpG/NP pretreatment reduced dendritic cell (DC) activation and lowered the frequencies of PD-L1+ DC in the mesenteric lymph nodes compared to whey-sensitized mice. By contrast, co-encapsulated BLG-Pep+CpG/NP pretreatment increased the frequency of splenic PD-L1+ DC compared to the BLG-Pep/NP plus CpG/NP recipients, in association with lower Th2 development and increased Treg/Th2 and Th1/Th2 ratios in the spleen. Oral administration of PLGA NP co-encapsulated with BLG-Pep and CpG prevented rise in serum BLG-specific IgE and symptom development while lowering splenic Th2 cell frequency in these mice which were kept under strict hygienic conditions.

Identification of peptides sequence and conformation contributed to potential allergenicity of main allergens in yogurts

Yogurts provide a good source of nutrition and may induce tolerance in people with cow's milk allergy (CMA). This study aimed to investigate the IgE-binding capacity of main allergens in the different yogurts which provide a reference for people with a high risk of CMA, and analyze the epitopes of major allergen peptides in yogurt. We assessed the degradation and the allergenic properties of major allergens in six commercial yogurts and fresh milk. The degradation of major allergens was analyzed by SDS-PAGE and RP-HPLC. Western blot and ELISA experiments detected allergenic characteristics by using specific sera. The results showed that β-lactoglobulin (Bos d 5) and α-lactalbumin (Bos d 4) were obviously degraded in yogurts but caseins were still present in abundance, which indicated that the proteases in yogurts were specific to whey proteins. IgE and IgG binding ability of major allergens were obviously reduced in yogurts, especially GuMi yogurt. In addition, 17 peptides of major allergens in GuMi yogurt were identified by LC-MS/MS and most of them were located in the interior of the spatial structure of proteins. Among them, 8 peptides had specific biological functions for health benefits, such as antibacterial, antioxidant, and ACE-inhibitory. We also found that 6 and 14 IgE epitopes of Bos d 5 and caseins were destroyed in GuMi yogurt, which could lead to the reduction of IgE-binding capacity. Meanwhile, peptides [Bos d 5 (AA15-40), Bos d 9 (AA120-151, AA125-151)] also preserved T cell epitopes, which might also induce the development of oral tolerance. Therefore, this study suggested that the sequence and conformation of peptides in yogurts contributed to hypoallergenicity.

Potential allergenicity and hydrolysis assessment of bovine casein and β-casein by treatment with lactic acid bacteria

Casein is one of the main allergens in cow's milk, accounting for 80% of cow's milk proteins. The ability of hydrolyzing proteins by bacteria is also different. In this study, the capacity of lactic acid bacteria to hydrolyze casein or β-casein and the IgG/IgE-binding capacity of hydrolysates were evaluated. The intensity of casein and β-casein degradation was analyzed by SDS-PAGE and RP-HPLC. The hydrolysates were tested for their capacity to inhibit IgG and IgE binding by ELISA. The peptides in the hydrolysate were also analyzed by LC-MS/MS. In these strains, Lactobacillus rhamnosus (CICC No. 22175) had the strongest hydrolysis of casein and β-casein. The hydrolysate of Lactobacillus rhamnosus (CICC No. 22175) showed the lowest antigenicity and potential allergenicity. It also hydrolyzed major allergen IgE epitopes and preserved T cell epitopes. Thereore Lactobacillus rhamnosus (CICC No. 22175) could be used for developing hypoallergenic dairy products and the development of tolerance. PRACTICAL APPLICATIONS: By the study, it obtained that a strain of Lactobacillus rhamnosus could effectively degrade casein and reduced the potential allergenicity of casein. At the same time, some major allergic epitopes were hydrolyzed and T cell epitopes were preserved. Therefore, it is very valuable for the application and development of lactic acid bacteria. The hydrolysate can also be used in a new hypoallergenic dairy formula with specific health benefits and promoting oral tolerance.

Accelerating skin regeneration and wound healing by controlled ROS from photodynamic treatment

Cellular metabolisms produce reactive oxygen species (ROS) which are essential for cellular signaling pathways and physiological functions. Nevertheless, ROS act as “double-edged swords” that have an unstable redox balance between ROS production and removal. A little raise of ROS results in cell proliferation enhancement, survival, and soft immune responses, while a high level of ROS could lead to cellular damage consequently protein, nucleic acid, and lipid damages and finally cell death. ROS play an important role in various pathological circumstances. On the contrary, ROS can show selective toxicity which is used against cancer cells and pathogens. Photodynamic therapy (PDT) is based on three important components including a photosensitizer (PS), oxygen, and light. Upon excitation of the PS at a specific wavelength, the PDT process begins which leads to ROS generation. ROS produced during PDT could induce two different pathways. If PDT produces control and low ROS, it can lead to cell proliferation and differentiation. However, excess production of ROS by PDT causes cellular photo damage which is the main mechanism used in cancer treatment. This review summarizes the functions of ROS in living systems and describes role of PDT in production of controllable ROS and finally a special focus on current ROS-generating therapeutic protocols for regeneration and wound healing.

Preparation, Characterization, and Biological Evaluation of a Hydrophilic Peptide Loaded on PEG-PLGA Nanoparticles

The encapsulation of peptides and proteins in nanosystems has been extensively investigated for masking unfavorable biopharmaceutical properties, including short half-life and poor permeation through biological membranes. Therefore, the aim of this work was to encapsulate a small antimicrobial hydrophilic peptide (H-Ser-Pro-Trp-Thr-NH2, FS10) in PEG-PLGA (polyethylene glycol-poly lactic acid-co-glycolic acid) nanoparticles (Nps) and thereby overcome the common limitations of hydrophilic drugs, which because they facilitate water absorption suffer from rapid degradation. FS10 is structurally related to the well-known RNAIII inhibiting peptide (RIP) and inhibits S. aureus biofilm formation. Various parameters, including different method (double emulsion and nanoprecipitation), pH of the aqueous phase and polymeric composition, were investigated to load FS10 into PEG-PLGA nanoparticles. The combination of different strategies resulted in an encapsulation efficiency of around 25% for both the double emulsion and the nanoprecipitation method. It was found that the most influential parameters were the pH—which tailors the peptides charge—and the polymeric composition. FS10-PEG-PLGA nanoparticles, obtained under optimized parameters, showed size lower than 180 nm with zeta potential values ranging from −11 to −21 mV. In vitro release studies showed that the Nps had an initial burst release of 48−63%, followed by a continuous drug release up to 21 h, probably caused by the porous character of the Nps. Furthermore, transmission electron microscopy (TEM) analysis revealed particles with a spherical morphology and size of around 100 nm. Antimicrobial assay showed that the minimum inhibitory concentration (MIC) of the FS10-loaded Nps, against S. aureus strains, was lower (>128 µg/mL) than that of the free FS10 (>256 µg/mL). The main goal of this work was to develop polymeric drug delivery systems aiming at protecting the peptide from a fast degradation, thus improving its accumulation in the target site and increasing the drug-bacterial membrane interactions.

Tiny tots for a big-league in wound repair: Tools for tissue regeneration by nanotechniques of today

Overall, chronic injuries place considerable burden on patients and health systems. The skin injuries are exposed to inflammatory bacteria and hinder the healing process. The skin being the biggest tissue of the whole body ensures protection against microbial invasion, dehydration, and against chemical, thermal, bright radiations and mechanical agents. When injured, the skin loses its defensive purpose and the attack of bacterial types arises with the loss of protein, water, and electrolytes. Improved wound closure therapy helps to restore normal skin function by managing wounds with the help of a suitable skin replacement. According to the type of wound and its healing ability, an appropriate skin replacement system must be identified. Nanofibrous layers because of their permeable structure, their large superficial reach and their similarity with the local extracellular network serve as cutaneous substitution for dealing with deep and superficial injuries. By a diminished microbial load without infestation, scab formation and infiltration of defense cells in the initial phase, acute injuries are usually characterized. Here recovery is related with epithelialization, angiogenesis and relocation of fibroblasts. The wound becomes obstinate when microbial biofilms are developed while the immune system does not manage to eliminate the infection. Increased inflammatory process, lower deep tissue oxygenation, fibrin cuffs, fibroblastic senescence, altered angiogenesis, stalled re-epithelialization and chronic infection have been visualized. Conventional wound mending treatments for the most part falling flat to supply a great clinical result, either basically like wound epithelialization and regulation of fluid loss or practically like histological highlights that decide versatility, strength, affectability, etc. Conventional wound therapies commonly fail to offer a better medical output, like wound epithelialization and regulation of fluid reduction or physiologically like cellular features that determine durability, sensitivity, elasticity, etc. Nanotechnology may be a dependable investigation space for wound-healing treatments through their versatile physicochemical properties. Advancing nano platforms with novel solutions for curing chronicdiabetic wounds are discussed in detail that can guide further research in this sector.

Glycosylated Ang-(1-7) MasR Agonist Peptide Poly Lactic-co-Glycolic Acid (PLGA) Nanoparticles and Microparticles in Cognitive Impairment: Design, Particle Preparation, Physicochemical Characterization, and In Vitro Release

Heart failure (HF) causes decreased brain perfusion in older adults, and increased brain and systemic inflammation increases the risk of cognitive impairment and Alzheimer’s disease (AD). Glycosylated Ang-(1-7) MasR agonists (PNA5) has shown improved bioavailability, stability, and brain penetration compared to Ang-(1-7) native peptide. Despite promising results and numerous potential applications, clinical applications of PNA5 glycopeptide are limited by its short half-life, and frequent injections are required to ensure adequate treatment for cognitive impairment. Therefore, sustained-release injectable formulations of PNA5 glycopeptide are needed to improve its bioavailability, protect the peptide from degradation, and provide sustained drug release over a prolonged time to reduce injection administration frequency. Two types of poly(D,L-lactic-co-glycolic acid) (PLGA) were used in the synthesis to produce nanoparticles (≈0.769−0.35 µm) and microparticles (≈3.7−2.4 µm) loaded with PNA5 (ester and acid-end capped). Comprehensive physicochemical characterization including scanning electron microscopy, thermal analysis, molecular fingerprinting spectroscopy, particle sizing, drug loading, encapsulation efficiency, and in vitro drug release were conducted. The data shows that despite the differences in the size of the particles, sustained release of PNA5 was successfully achieved using PLGA R503H polymer with high drug loading (% DL) and high encapsulation efficiency (% EE) of >8% and >40%, respectively. While using the ester-end PLGA, NPs showed poor sustained release as after 72 h, nearly 100% of the peptide was released. Also, lower % EE and % DL values were observed (10.8 and 3.4, respectively). This is the first systematic and comprehensive study to report on the successful design, particle synthesis, physicochemical characterization, and in vitro glycopeptide drug release of PNA5 in PLGA nanoparticles and microparticles.

An updated review on food-derived bioactive peptides: Focus on the regulatory requirements, safety, and bioavailability

Food-derived bioactive peptides (BAPs) are recently utilized as functional food raw materials owing to their potential health benefits. Although there is a huge amount of scientific research about BAPs' identification, purification, characterization, and physiological functions, and subsequently, many BAPs have been marketed, there is a paucity of review on the regulatory requirements, bioavailability, and safety of BAPs. Thus, this review focuses on the toxic peptides that could arise from their primary proteins throughout protein extraction, protein pretreatment, and BAPs' formulation. Also, the influences of BAPs' length and administration dosage on safety are summarized. Lastly, the challenges and possibilities in BAPs' bioavailability and regulatory requirements in different countries were also presented. Results revealed that the human studies of BAPs are essential for approvals as healthy food and to prevent the consumers from misinformation and false promises. The BAPs that escape the gastrointestinal tract epithelium and move to the stomach are considered good peptides and get circulated into the blood using different pathways. In addition, the hydrophobicity, net charge, molecular size, length, amino acids composition/sequences, and structural characteristics of BAPs are critical for bioavailability, and appropriate food-grade carriers can enhance it. The abovementioned features are also vital to optimize the solubility, water holding capacity, emulsifying ability, and foaming property of BAPs in food products. In the case of safety, the possible allergenic and toxic peptides often exhibit physiological functions and could be produced during the hydrolysis of food proteins. It was also noted that the production of iso-peptides bonds and undesirable Maillard reaction might occur during protein extraction, sample pretreatments, and peptide synthesis.

Nanoparticles in allergen immunotherapy

PURPOSE OF REVIEW

Allergen immunotherapy is the only recognized causal treatment for allergic disease that modulates the immune system toward a tolerogenic or desensitized state. Allergens or their derivative preparations are formulated with adjuvants of different origin and having diverse immunological functions, such as prolonged tissue release and specific immunomodulatory properties. In the last 2 decades, thanks to developments in the field of nanotechnology, more biosafe nanoscale materials have become available for use as pharmaceutical adjuvants in medical research.

RECENT FINDINGS

Nanomaterials possess unique and versatile properties which can be employed to develop drug carriers with safer profiles, better stability in physiological conditions and immunomodulatory properties. Nanoparticles can have an adjuvant effect per se or also when they are packed in structures whose physical-chemical properties can be handled in a way that also influences its release dynamics. In particular, it has been suggested that nanoparticle preparations can be put in complexes or loaded with allergens or allergenic extracts, opening the way to innovative paradigms.

SUMMARY

In this review, we analyze allergen/nanoparticle properties in terms of cytotoxicity, stability and immunogenic reaction in in-vitro and animal systems.

Oral delivery of proteins and peptides: Challenges, status quo and future perspectives

Proteins and peptides (PPs) have gradually become more attractive therapeutic molecules than small molecular drugs due to their high selectivity and efficacy, but fewer side effects. Owing to the poor stability and limited permeability through gastrointestinal (GI) tract and epithelia, the therapeutic PPs are usually administered by parenteral route. Given the big demand for oral administration in clinical use, a variety of researches focused on developing new technologies to overcome GI barriers of PPs, such as enteric coating, enzyme inhibitors, permeation enhancers, nanoparticles, as well as intestinal microdevices. Some new technologies have been developed under clinical trials and even on the market. This review summarizes the history, the physiological barriers and the overcoming approaches, current clinical and preclinical technologies, and future prospects of oral delivery of PPs.

Inhibition of cow's milk allergy development in mice by oral delivery of β-lactoglobulin-derived peptides loaded PLGA nanoparticles is associated with systemic whey-specific immune silencing

Background

Two to four percentage of infants are affected by cow's milk allergy (CMA), which persists in 20% of cases. Intervention approaches using early oral exposure to cow's milk protein or hydrolysed cow's milk formula are being studied for CMA prevention. Yet, concerns regarding safety and/or efficacy remain to be tackled in particular for high‐risk non‐exclusively breastfed infants. Therefore, safe and effective strategies to improve early life oral tolerance induction may be considered.

Objective

We aim to investigate the efficacy of CMA prevention using oral pre‐exposure of two selected 18‐AA β‐lactoglobulin‐derived peptides loaded poly (lactic‐co‐glycolic acid) (PLGA) nanoparticles (NPs) in a whey‐protein induced CMA murine model.

Methods

The peptides were loaded in PLGA NPs via a double emulsion solvent evaporation technique. In vivo, 3‐week‐old female C3H/HeOuJ mice received 6 daily gavages with PBS, whey, Peptide‐mix, a high‐ or low‐dose Peptide‐NPs or empty‐NP plus Peptide‐mix, prior to 5 weekly oral sensitizations with cholera toxin plus whey or PBS (sham). One week after the last sensitization, the challenge induced acute allergic skin response, anaphylactic shock score, allergen‐specific serum immunoglobulins and ex vivo whey‐stimulated cytokine release by splenocytes was measured.

Results

Mice pre‐treated with high‐dose Peptide‐NPs but not low‐dose or empty‐NP plus Peptide‐mix, were protected from anaphylaxis and showed a significantly lower acute allergic skin response upon intradermal whey challenge compared to whey‐sensitized mice. Compared with the Peptide‐mix or empty‐NP plus Peptide‐mix pre‐treatment, the high‐dose Peptide‐NPs‐pre‐treatment inhibited ex vivo whey‐stimulated pro‐inflammatory cytokine TNF‐α release by splenocytes.

Conclusion & Clinical relevance

Oral pre‐exposure of mice to two β‐lactoglobulin‐derived peptides loaded PLGA NPs induced a dose‐related partial prevention of CMA symptoms upon challenge to whole whey protein and silenced whey‐specific systemic immune response. These findings encourage further development of the concept of peptide‐loaded PLGA NPs for CMA prevention towards clinical application.

New Insights in Therapy for Food Allergy

Food allergy is an increasing problem worldwide, with strict avoidance being classically the only available reliable treatment. The main objective of this review is to cover the latest information about the tools available for the diagnosis and treatment of food allergies. In recent years, many efforts have been made to better understand the humoral and cellular mechanisms involved in food allergy and to improve the strategies for diagnosis and treatment. This review illustrates IgE-mediated food hypersensitivity and provides a current description of the diagnostic strategies and advances in different treatments. Specific immunotherapy, including different routes of administration and new therapeutic approaches, such as hypoallergens and nanoparticles, are discussed in detail. Other treatments, such as biologics and microbiota, are also described. Therefore, we conclude that although important efforts have been made in improving therapies for food allergies, including innovative approaches mainly focusing on efficacy and safety, there is an urgent need to develop a set of basic and clinical results to help in the diagnosis and treatment of food allergies.

A20-OVA Nanoparticles Inhibit Allergic Asthma in a Murine Model

The skewed T helper (Th) 2 response plays a critical role in the pathogenesis of allergic asthma. Regulatory T (Treg) cells and the regulatory cytokines are required in maintaining the homeostasis in the body. This study aims to determine the effects of a poly(lactic-co-glycolic) acid (PLGA)-ovalbumin (OVA)+A20 (a ubiquitin E3 ligase) nanovaccine on inhibiting allergic asthma in a murine model. In this study, A20 and OVA (a model antigen) were encapsulated into PLGA to be a nanovaccine (PLGA-OVA+A20). An allergic asthma murine model was developed with OVA as the specific antigen to test the role of PLGA-OVA+A20 nanovaccine in maintaining the immune homeostasis in the airway tissues. The results showed that PLGA-OVA+A20 nanovaccine inhibited the asthma responses in mice by suppressing Th2 inflammatory responses, promoting the generation of Treg cells in the airway tissues. We conclude that the PLGA-OVA+A20 nanovaccine has a marked inhibitory effect on the airway allergic response in sensitized mice by significantly promoting the generation of Treg cell and IL-10. The data suggest that PLGA-OVA+A20 has translational potential in the treatment of allergic asthma.

Nanomedicine for Drug Delivery throughout the Alimentary Canal

The field of nanomedicine continues to grow with new technologies and formulations in development for several disease states. Much research focuses on the use of injectable nanomedicines for treatment of neoplasms; however, there are several formulations in development that use nanotechnology that can be administered enterally for noncancer indications. These nanomedicine treatments have been developed for systemic drug delivery or local drug delivery along the gastrointestinal tract. This Review gives a brief overview of the alimentary canal and highlights new research in nanomedicine in noncancer disease states delivered via enteral routes of administration. Relevant recent research is summarized on the basis of the targeted site of action or absorption, including the buccal, sublingual, stomach, small intestine, and large intestine areas of the alimentary canal. The benefits of nanodrug delivery are discussed as well as barriers and challenges for future development in the field.

Oral peptide delivery: challenges and the way ahead

Peptides and proteins have emerged as potential therapeutic agents and, in the search for the best treatment regimen, the oral route has been extensively evaluated because of its non-invasive and safe nature. The physicochemical properties of peptides and proteins along with the hurdles in the gastrointestinal tract (GIT), such as degrading enzymes and permeation barriers, are challenges to their delivery. To address these challenges, several conventional and novel approaches, such as nanocarriers, site-specific and stimuli specific delivery, are being used. In this review, we discuss the challenges to the oral delivery of peptides and the approaches used to tackle these challenges.

Penicillin G Induces H+, K+-ATPase via a Nitric Oxide-Dependent Mechanism in the Rat Colonic Crypt

BACKGROUND/AIMS

The colonic H+, K+ ATPase (HKA2) is a heterodimeric membrane protein that exchanges luminal K+ for intracellular H+ and is involved in maintaining potassium homeostasis. Under homeostatic conditions, the colonic HKA2 remains inactive, since most of the potassium is absorbed by the small intestine. In diarrheal states, potassium is secreted and compensatory potassium absorption becomes necessary. This study proposes a novel mechanism whereby the addition of penicillin G sodium salt (penG) to colonic crypts stimulates potassium uptake in the presence of intracellular nitric oxide (NO), under sodium-free (0-Na+) conditions.

METHODS

Sprague Dawley rat colonic crypts were isolated and pHi changes were monitored through the ammonium prepulse technique. Increased proton extrusion in 0-Na+ conditions reflected heightened H+, K+ ATPase activity. Colonic crypts were exposed to penG, L-arginine (a NO precursor), and N-nitro l-arginine methyl ester (L-NAME, a NO synthase inhibitor).

RESULTS

Isolated administration of penG significantly increased H+, K+ ATPase activity from baseline, p 0.0067. Co-administration of arginine and penG in 0-Na+ conditions further upregulated H+, K+ ATPase activity, p <0.0001. Crypt perfusion with L-NAME and penG demonstrated a significant reduction in H+, K+ ATPase activity, p 0.0058.

CONCLUSION

Overall, acute exposure of colonic crypts to penG activates the H+, K+ ATPase in the presence of NO. This study provides new insights into colonic potassium homeostasis.

Three Candidate Probiotic Strains Impact Gut Microbiota and Induce Anergy in Mice with Cow's Milk Allergy

We showed previously that three probiotic strains, i.e., Lactobacillus rhamnosus LA305, L. salivarius LA307, and Bifidobacterium longum subsp. infantis LA308, exerted different preventive effects in a mouse model of cow’s milk allergy. In this study, we evaluated their potential benefits in a curative mouse model of cow’s milk allergy. When administered for 3 weeks after the sensitization process and a first allergic reaction, none of the strains modified the levels of sensitization and allergic markers. However, all three strains affected gut bacterium communities and modified immune and inflammatory responses, leading to a tolerogenic profile. Interestingly, all three strains exerted a direct effect on dendritic cells, which are known to play a major role in food sensitization through their potentially tolerogenic properties and anergic responses. Taken together, these data indicate a potentially beneficial role of the probiotic strains tested in this model of cow’s milk allergy with regard to tolerance acquisition.

Cow’s milk allergy is a worldwide public health issue, especially since there is no effective treatment, apart from milk and dairy product avoidance. The aim of this study was to assess the beneficial role of three probiotic strains previously selected for their prophylactic properties in a mouse model of β-lactoglobulin allergy. Administration of Lactobacillus rhamnosus LA305, L. salivarius LA307, or Bifidobacterium longum subsp. infantis LA308 for 3 weeks post–sensitization and challenge modified the composition of the gut microbiota, with an increase in the Prevotella NK3B31 group and a decrease in Marvinbryantia, belonging to the Lachnospiraceae family. Although no impact on markers of sensitization was detected, modifications of foxp3, tgfβ, and il10 ileal gene expression, as well as plasma metabolomic alterations in the tryptophan pathway, were observed. Moreover, ex vivo studies showed that all probiotic strains induced significant decreases in cytokine production by β-lactoglobulin-stimulated splenocytes. Taken together, these results suggest that the three probiotic strains tested lead to alterations in immune responses, i.e., induction of a tolerogenic anergy and anti-inflammatory responses. This anergy could be linked to cecal microbiota modifications, although no impact on fecal short-chain fatty acid (SCFA) concentrations was detected. Anergy could also be linked to a direct impact of probiotic strains on dendritic cells, since costimulatory molecule expression was decreased following coincubation of these strains with bone marrow-derived dendritic cells (BMDCs). To conclude, all three candidate probiotic strains induced strain-specific gut microbiota and metabolic changes, which could potentially be beneficial for general health, as well as anergy, which could contribute to oral tolerance acquisition.

IMPORTANCE We showed previously that three probiotic strains, i.e., Lactobacillus rhamnosus LA305, L. salivarius LA307, and Bifidobacterium longum subsp. infantis LA308, exerted different preventive effects in a mouse model of cow’s milk allergy. In this study, we evaluated their potential benefits in a curative mouse model of cow’s milk allergy. When administered for 3 weeks after the sensitization process and a first allergic reaction, none of the strains modified the levels of sensitization and allergic markers. However, all three strains affected gut bacterium communities and modified immune and inflammatory responses, leading to a tolerogenic profile. Interestingly, all three strains exerted a direct effect on dendritic cells, which are known to play a major role in food sensitization through their potentially tolerogenic properties and anergic responses. Taken together, these data indicate a potentially beneficial role of the probiotic strains tested in this model of cow’s milk allergy with regard to tolerance acquisition.

Effects of whey protein hydrolysate on growth promotion and immunomodulation in mouse pups in artificial rearing system

This study aimed to investigate the effects of whey protein hydrolysate (WPH) on the growth and immunity of mouse pups in artificial rearing (AR) system. Mouse pups were reared in the AR system with artificial milk including 5% WPH (AR with WPH) or not (AR without WPH), and the remaining pups were reared by their mother (dam) for 14 days after birth. The body weight change and body weight gain rates in the AR with WPH group were significantly higher than those observed in the AR without WPH group and similar to those in the dam group. Moreover the feed and protein efficiencies in the AR with WPH group were significantly higher than those of the AR without WPH group. In addition, the supplement of WPH in the AR system was shown to significantly elevate the number of CD3⁺ CD8⁺ , B220⁺ CD19⁺ , IA/IE⁺ CD11c⁺ , and CD11b⁺ in the thymocyte and/or splenocyte, and the thymus weight. Furthermore, MALDI-TOF/MS analysis identified the amino acid sequences corresponding to some peptides, and indicated that VRTPEVDDE had the highest relative intensity among the peptides from tested WPH. Therefore, WPH would be required to not only promote growth, but also exert immunomodulatory activities in mouse pups in AR system.

Formulations for Allergen Immunotherapy in Human and Veterinary Patients: New Candidates on the Horizon

Allergen immunotherapy is currently the only causal treatment for allergic diseases in human beings and animals. It aims to re-direct the immune system into a tolerogenic or desensitized state. Requirements include clinical efficacy, safety, and schedules optimizing patient or owner compliance. To achieve these goals, specific allergens can be formulated with adjuvants that prolong tissue deposition and support uptake by antigen presenting cells, and/or provide a beneficial immunomodulatory action. Here, we depict adjuvant formulations being investigated for human and veterinary allergen immunotherapy.

Mechanisms of Particles in Sensitization, Effector Function and Therapy of Allergic Disease

Humans have always been in contact with natural airborne particles from many sources including biologic particulate matter (PM) which can exhibit allergenic properties. With industrialization, anthropogenic and combustion-derived particles have become a major fraction. Currently, an ever-growing number of diverse and innovative materials containing engineered nanoparticles (NPs) are being developed with great expectations in technology and medicine. Nanomaterials have entered everyday products including cosmetics, textiles, electronics, sports equipment, as well as food, and food packaging. As part of natural evolution humans have adapted to the exposure to particulate matter, aiming to protect the individual's integrity and health. At the respiratory barrier, complications can arise, when allergic sensitization and pulmonary diseases occur in response to particle exposure. Particulate matter in the form of plant pollen, dust mites feces, animal dander, but also aerosols arising from industrial processes in occupational settings including diverse mixtures thereof can exert such effects. This review article gives an overview of the allergic immune response and addresses specifically the mechanisms of particulates in the context of allergic sensitization, effector function and therapy. In regard of the first theme (i), an overview on exposure to particulates and the functionalities of the relevant immune cells involved in allergic sensitization as well as their interactions in innate and adaptive responses are described. As relevant for human disease, we aim to outline (ii) the potential effector mechanisms that lead to the aggravation of an ongoing immune deviation (such as asthma, chronic obstructive pulmonary disease, etc.) by inhaled particulates, including NPs. Even though adverse effects can be exerted by (nano)particles, leading to allergic sensitization, and the exacerbation of allergic symptoms, promising potential has been shown for their use in (iii) therapeutic approaches of allergic disease, for example as adjuvants. Hence, allergen-specific immunotherapy (AIT) is introduced and the role of adjuvants such as alum as well as the current understanding of their mechanisms of action is reviewed. Finally, future prospects of nanomedicines in allergy treatment are described, which involve modern platform technologies combining immunomodulatory effects at several (immuno-)functional levels.

Nanoparticle-based immunotherapy: state of the art and future perspectives

INTRODUCTION

For several years now, medicine has been benefiting from the contribution of nanoparticles (NPs) technology for both diagnosis and therapy. They can be used as adjuvants, being capable per se of immune-modulating activity, or as carriers for molecules to be transported to a specific target, eventually loaded with specific ligands favoring specific uptake.

AREAS COVERED

The review focuses on experimental use of NPs as adjuvants/carriers for allergen immunotherapy (AIT). Human clinical trials conducted so far are discussed.

EXPERT OPINION

Results of experimental studies and recent clinical trials support the use of NPs as carrier/adjuvant in AIT. Comparisons between NP-based and classical AIT are needed, to show the usefulness of the NP-based approach. However, there are still unsolved problems: the persistence of non-degradable NPs with possible toxicological consequences, and the formation of the protein corona around the NPs, which could alter their activity and fate. Virus-like particles seem the most promising NPs for allergy treatment, as for other vaccines. Over the next decade, NP-based AIT will be largely used to treat allergic disorders.

A Solid-in-Oil Nanodispersion System for Transcutaneous Immunotherapy of Cow's Milk Allergies

An allergy to cow’s milk proteins is the most common food allergy in infants and toddlers. Conventional oral immunotherapy for cow’s milk allergies requires hospital admission due to the risk of severe allergic reactions, including anaphylaxis. Therefore, a simpler and safer immunotherapeutic method is desirable. We examined transcutaneous immunotherapy with a solid-in-oil (S/O) system. In the S/O system, nano-sized particles of proteins are dispersed in an oil-vehicle with the assistance of nonionic surfactants. In the present study, the S/O system enhanced the skin permeation of the allergen molecule β-lactoglobulin (BLG), as compared with a control PBS solution. The patches containing BLG in the S/O nanodispersion skewed the immune response in the allergy model mice toward T helper type 1 immunity, indicating the amelioration of allergic symptoms. This effect was more pronounced when the immunomodulator resiquimod (R-848) was included in the S/O system.

Encapsulation of Antihypertensive Peptides from Whey Proteins and Their Releasing in Gastrointestinal Conditions

Antihypertensive peptide fraction from whey protein hydrolysate <3 kDa (measured as angiotensin-converting enzyme (ACE) activity %) was isolated and encapsulated into three composite materials: alginate-collagen, alginate Arabic gum, and alginate-gelatin. The release behavior of peptide fraction from capsules was analyzed according to the encapsulation material efficiency, the characteristics of the capsules, and the released antihypertensive peptides during gastrointestinal digestion. The highest encapsulation efficiency was found in capsules of alginate Arabic gum (95%). In this case, the released peptides incremented their ACE activity (85%) after the digestion process, with respect to the initial ACE activity (74%). Whey antihypertensive fraction revealed five peptide sequences; however, other amino acid sequences were released from digested capsules. Protein databases confirmed some antihypertensive sequences indicating the peptides content from β-Lg and α-La. Consequently, new peptides could be revealed from whey antihypertensive fraction.