Treatment with oleic acid reduces IgE binding to peanut and cashew allergens

Comparative study of binding interactions between different fatty acids and β-lactoglobulin:Impact on conformation and physicochemical properties of the protein

A comparative study was conducted to investigate the binding mechanisms and interactions between four different lengths of saturated fatty acids (C12:0 to C18:0) and two types of C18 unsaturated fatty acids (C18:1 and C18:2) with β-lactoglobulin (β-Lg). The quenching mechanism for these six fatty acids - lauric acid (LUA), myristic acid (MA), palmitic acid (PAL), stearic acid (SA), oleic acid (OA), and linoleic acid (LA) - with β-Lg were found to be static, and the interactions were predominantly driven by hydrophobic forces. The binding affinity was increased with the increase of carbon chain. While, an increase in the number of CC double bonds resulted in a decreased in binding affinity. The binding of fatty acids interfered with the micro-environment around the tyrosine (Tyr) and tryptophan (Trp) residues in protein, subsequently altering the secondary structures of β-Lg. This study will help to improve our understanding of nutrient interactions in food.

Influence of lecithin on the digestibility and immunoreactivity of β-conglycinin

A growing body of evidence suggests that protein structure can be uniquely altered by lipids. However, the role of lecithin on the digestibility and immunoreactivity of allergenic protein remains poorly understood. Therefore, we investigated the impact of different protein/lecithin (P:L) ratios (5:1, 10:1, 20:1, 30:1 and 40:1) on the digestion properties, peptide profiles and immunoreactivity of β-conglycinin in vitro simulated gastrointestinal digestion. Results revealed that lecithin addition increased the degree of hydrolysis and digestion rate of β-conglycinin during digestion in a dose-dependent manner, which may be attributed to the enhancement of pepsin activity. Additionally, the addition of lecithin contributed to the dispersion and homogeneity of β-conglycinin digestion products. When the ratio of lecithin to β-conglycinin was 1:10, the obtained β-conglycinin digestion products exhibited the highest DH value (23.80 %) and the lowest antigenicity (52.69%) in the intestinal digestion. Peptidomics and immunoinformatic analysis further confirmed that PL-10 disrupted 18/30, 15/44, and 37/75 epitopes in the α, α', and β subunits of β-conglycinin, respectively. These results suggested that lecithin changed the cleavage preferences of β-conglycinin, and promoted the disruption of allergic epitopes, specifically for the β subunit. The study can contribute to our understanding of the role of lecithin in the digestion properties and immunoreactivity of allergenic protein.

Long-chain fatty acids block allergic reaction against lipid transfer protein Sola l 7 from tomato seeds

Due to the benefits of tomato as an antioxidant and vitamin source, allergy to this vegetable food is a clinically concerning problem. Sola l 7, a class I lipid transfer protein found in tomato seeds, has been identified as an allergen linked to severe anaphylaxis. However, the role of lipid binding in Sola l 7-induced allergy remains unclear. Here, the three-dimensional structure of recombinant Sola l 7 (rSola l 7) has been elucidated using nuclear magnetic resonance spectroscopy (NMR). Its interaction with free fatty acids has been deeply studied; fluorescence emission spectroscopy revealed that different long-chain fatty acids interact with the protein, affecting the only tyrosine residue present in Sola l 7. On the contrary, no changes in the overall secondary structure were observed after the analysis of the circular dichroism spectra in the presence of fatty acids. Unsaturated oleic and linoleic fatty acids presented higher affinity and promoted more significant changes than saturated or short-chain fatty acids. 1H-15N HSQC NMR spectra allowed to determine the regions of the protein that were modified when rSola l 7 interacts with the fatty acids, suggesting epitope modification after the interaction. For corroboration, IgG and IgE binding to rSola l 7 were assessed in the presence of free fatty acids, revealing that both IgE and IgG binding were significantly lower than in their absence, suggesting a potential protective role of unsaturated fatty acids in tomato allergy.

Enzymatic synthesis and characterization of novel lipophilic inotodiol-oleic acid conjugates

In this study, we establish an efficient enzymatic approach for producing novel inotodiyl-oleates (IOs) from pure inotodiol and oleic acid to improve the properties of inotodiol. For the esterification between inotodiol and oleic acid, CALA and n-hexane were the optimal biocatalyst and solvents for forming IOs with 80.17% conversion yield. These IOs comprised two distinct monoesters, the C3 or C22 ester forms of inotodiol. Intriguingly, no diesters were detected. The IOs had a melting point of 53.48 °C, much lower than that of inotodiol (192.06 °C). The in vitro digestion rate of IOs (25-28%) was significantly (p < 0.05) lower than that of cholesteryl-oleate (60%). Additionally, IOs exhibited much lower in vivo absorption than inotodiol when orally administered using different formulations (p < 0.05). The results indicated that IOs were resistant to enzymatic digestion in the small intestine, which could be advantageous in targeting the large intestine for disease treatments.

Formation, characterization, and antigenicity of lecithin-β-conglycinin complexes

Lipid binding has been proposed to represent a functional property of many allergenic proteins. This study investigated the formation, characterization, and antigenicity of lecithin-β-conglycinin complexes. The results indicate that lecithin was combined with β-conglycinin via static quenching and primarily driven by hydrogen bonds and van der Waals forces. In addition, heat treatment reduced the antigenicity of complexes, as evidenced by changes in molecular weight and secondary and tertiary structures. It revealed that large aggregates developed and more hydrophobic regions were exposed for complexes after heat treatment, as well as a decrease in the β-sheet contents and an increase in the β-turn and random coil contents. Furthermore, the average particle size of the complexes increased with increased temperature treatment, and the morphology of the complexes exhibited an amorphous polymer. These findings shedlight on the interaction between lecithin and β-conglycinin and help us understand the role of lecithin in allergic reactions.

Effect of processing treatments on the allergenicity of nuts and legumes: A meta-analysis

The effective food processing to reduce nuts and legumes allergenicity could not be easily and directly concluded from reading a few published reports. Therefore, we conducted a meta-analysis to investigate this issue. A literature search was conducted in eight electronic databases from January 2000 to June 11, 2021. The primary outcome of interest was the allergenicity of processed nuts or legumes determined by enzyme-linked immunosorbent assay from in vitro studies. Data with the standardized mean difference (SMD) of 95% confidence interval (CI) were pooled using a random-effect model by RevMan 5.4 software. Heterogeneity was assessed using Cochran's Q (P_Q ) and I² tests. The search strategy identified 18,793 articles. However, only 61 studies met the inclusion criteria and were included in this meta-analysis. There were 21 and 15 types of respective single and combined food processing treatments analyzed for their effects on reducing allergenicity. In single processing treatment, the extrusion and fermentation had the largest reduction in allergenicity, considering their SMD value, that is, -20.19 (95% CI: -22.22 to -18.17; the certainty of evidence: moderate) and -20.8 (95% CI: -24.10 to -17.50; the certainty of evidence: moderate), respectively. Whereas in the combination, the treatment of fermentation followed by proteolytic hydrolysis showed the most significant reduction (SMD: -53.34; 95% CI: -70.18 to -36.5) and the evidence quality of this treatment was considered moderate. In conclusion, these three food processing methods showed a desirable impact in reducing nuts or legumes allergenicity. PRACTICAL APPLICATION: Nuts and legumes play an essential role as protein sources in food consumption worldwide, but they usually contain allergens. Our study has investigated the food processing methods that effectively reduce their allergenicity by meta-analysis. The result gives valuable information for further laboratory investigation on allergens and can be used by food industries in providing foods from nuts and legumes with lower allergenicity.

Nut Allergenicity: Effect of Food Processing

Nuts are considered healthy foods due to their high content of nutritional compounds with functional properties. However, the list of the most allergenic foods includes tree nuts, and their presence must be indicated on food labels. Most nut allergens are seed storage proteins, pathogenesis-related (PR) proteins, profilins and lipid transfer proteins (LTP). Nut allergenic proteins are characterized by their resistance to denaturation and proteolysis. Food processing has been proposed as the method of choice to alter the allergenicity of foods to ensure their safety and improve their organoleptic properties. The effect of processing on allergenicity is variable by abolishing existing epitopes or generating neoallergens. The alterations depend on the intrinsic characteristics of the protein and the type and duration of treatment. Many studies have evaluated the molecular changes induced by processes such as thermal, pressure or enzymatic treatments. As some processing treatments have been shown to decrease the allergenicity of certain foods, food processing may play an important role in developing hypoallergenic foods and using them for food tolerance induction. This work provides an updated overview of the applications and influence of several processing techniques (thermal, pressure and enzymatic digestion) on nut allergenicity for nuts, namely, hazelnuts, cashews, pistachios, almonds and walnuts.

Cryptotympana pustulata Extract and Its Main Active Component, Oleic Acid, Inhibit Ovalbumin-Induced Allergic Airway Inflammation through Inhibition of Th2/GATA-3 and Interleukin-17/RORγt Signaling Pathways in Asthmatic Mice

Cicadae Periostracum (CP), derived from the slough of Cryptotympana pustulata, has been used as traditional medicine in Korea and China because of its diaphoretic, antipyretic, anti-inflammatory, antioxidant, and antianaphylactic activities. The major bioactive compounds include oleic acid (OA), palmitic acid, and linoleic acid. However, the precise therapeutic mechanisms underlying its action in asthma remain unclear. The objective of this study was to determine the antiasthmatic effects of CP in an ovalbumin (OVA)-induced asthmatic mouse model. CP and OA inhibited the inflammatory cell infiltration, airway hyperresponsiveness (AHR), and production of interleukin (IL)7 and Th2 cytokines (IL-5) in the bronchoalveolar lavage fluid and OVA-specific imunoglobin E (IgE) in the serum. The gene expression of IL-5, IL-13, CCR3, MUC5AC, and COX-2 was attenuated in lung tissues. CP and OA might inhibit the nuclear translocation of GATA-binding protein 3 (GATA-3) and retinoic acid receptor-related orphan receptor γt (RORγt) via the upregulation of forkhead box p3 (Foxp3), thereby preventing the activation of GATA-3 and RORγt. In the in vitro experiment, a similar result was observed for Th2 and GATA-3. These results suggest that CP has the potential for the treatment of asthma via the inhibition of the GATA-3/Th2 and IL-17/RORγt signaling pathways.

Conformational changes in bovine α-lactalbumin and β-lactoglobulin evoked by interaction with C18 unsaturated fatty acids provide insights into increased allergic potential

Bovine α-lactalbumin (BLA) and β-lactoglobulin (BLG) are the most common and severe food allergens in milk and they can bind C18 unsaturated fatty acids (UFAs) and their bioactivities were changed. This study aims to determine the effects of C18 UFAs on the structures of BLA and BLG and their allergic properties, such as antigenicity and allergenicity. We reveal that C18 UFAs can efficiently promote the gradual unfolding of the structures of BLA and BLG and increase their hydrophobicity. Moreover, the IgG binding ability and the expression of IgG-dependent activation marker CD200R3 on basophils were remarkably promoted after C18 UFA treatment. Finally, we also observed that C18 UFAs can enhance the IgE binding ability and the degranulation capacity of human basophil KU812 cells (intracellular Ca2+, histamine, β-Hex, and IL-6). Collectively, these results suggested that C18 UFAs changed the structures of BLA and BLG, which contributed to their increased allergic potential.

Improved antitumor activity and IgE/IgG-binding ability of α-Lactalbumin/β-lactoglobulin induced by ultrasonication prior to binding with oleic acid

Bovine α-lactalbumin (α-La)/β-lactoglobulin (β-Lg) was pretreated through ultrasonic treatment and subsequently binding with oleic acid (OA) by heat treatment. And, the antitumor activity, IgE/IgG-binding ability, and structural modifications were investigated. After α-La/β-Lg were treated by ultrasonic prior to binding with OA, the treated α-La/β-Lg showed high antitumor activity and IgE/IgG-binding ability, and significantly affected the structural modifications, which reflected by the reduction in α-helix content, the increase of molecular weight, intrinsic fluorescence intensity, and surface hydrophobicity. Molecular docking studies indicated that OA bound to α-La/β-Lg by hydrogen bonds and hydrophobic interaction. Therefore, ultrasonic prior to binding with OA could improve antitumor activity and IgE/IgG-binding ability of α-La/β-Lg as a result of structural modifications. And, ultrasonic prior to binding with fatty acid processing of milk products alone may increase the antitumor activity, this change may enhance the risk of an allergenic reaction in milk allergy patients to some extent. PRACTICAL APPLICATIONS: Fatty acids, natural ligands associated with the bovine milk proteins, and milk protein-fatty acid complex has a variety of functional applications in the food industry. This study revealed that antitumor activity, IgE/IgG-binding ability, and structural modifications of α-La/β-Lg induced by ultrasonic prior to binding with oleic acid. It will be beneficial to understand the mechanism of the functional changes of protein. Ultrasonic prior to binding with oleic acid will be more likely to develop a practical technology to improve the functional characteristics of milk protein and design the optimal nutritional performance of milk food.

Role of dietary lipids in food allergy

The prevalence of food allergy is raising in industrialized countries, but the mechanisms behind this increased incidence are not fully understood. Environmental factors are believed to play a role in allergic diseases, including lifestyle influences, such as diet. There is a close relationship between allergens and lipids, with many allergenic proteins having the ability to bind lipids. Dietary lipids exert pro-inflammatory or anti-inflammatory functions on cells of the innate immunity and influence antigen presentation to cells of the adaptive immunity. In addition to modifying the immunostimulating properties of proteins, lipids also alter their digestibility and intestinal absorption, changing allergen bioavailability. This study provides an overview of the role of dietary lipids in food allergy, taking into account epidemiological information, as well as results of mechanistic investigations using in vivo, ex vivo and in vitro models. The emerging link among high-fat diets, obesity, and allergy is also discussed.

Camellia japonica oil suppressed asthma occurrence via GATA-3 & IL-4 pathway and its effective and major component is oleic acid

BACKGROUND

In December 2016, WHO released a report stating that in 2015 there were 383,000 deaths caused by asthma and 235 million people suffering from asthma. As there are many adverse effects associated with the currently-used asthma drugs, new anti-asthmatic drugs need to be developed.

PURPOSE

In order to find new drug candidates with safe and low side effects, the anti-asthmatic function and mechanism of C. japonica oil were evaluated, and its active ingredients were analyzed for use in an ovalbumin asthma murine model.

STUDY DESIGN AND METHODS

The study consisted of six groups: control; ovalbumin group; and dexamethasone group as a positive control; and 10, 100, and 500 mg/kg C. japonica oil treatment groups. In order to measure the anti-asthmatic effect of C. japonica oil, WBC and differential cell count in BALF, IgE in serum, morphological changes in pulmonary system, and gene and protein levels such as IFN-γ, IL-12p40, IL-4, IL-5, IL-6, TNF-α, and IL-6 were all evaluated.

RESULTS

C. japonica oil had an anti-asthmatic effect and significantly controlled eosinophil in BALF, Th2-related factors such as GATA-3 that is Th2 cell transcription factor, IL-4, IL-5, and IL-13, and TNF-α in the lung. It also dose-dependently modulated inflammatory cells, T-bet, IL-12p40, and IL-6. Oleci acid was the major gradient (52.89%) in C. japonica oil and also had anti-asthmatic effects such as the downregulation of inflammatory cells, WBC, and eosinophil in BALF, IgE in serum, and morphological changes in the lung.

CONCLUSION

We concluded that C. japonica oil is a new anti-asthmatic drug candidate and that oleic acid is the major anti-asthmatic ingredient in C. japonica oil.

The Ethanol Extract of Holotrichia diomphalia Larvae, Containing Fatty acids and Amino acids, Exerts Anti-Asthmatic Effects through Inhibition of the GATA-3/Th2 Signaling Pathway in Asthmatic Mice

Holotrichia diomphalia larvae (HD), a natural product from an insect resource, possesses many pharmacological properties, including anticoagulant, antitumor, anti-inflammatory, and analgesic activity. The major bioactive ingredients include oleic acid, palmitic acid, palmitoleic acid, linoleic acid, proline, and glutamic acid. Although HD is associated with immunoregulatory activities in allergic diseases, the therapeutic mechanisms of the action of HD in allergic diseases have not been investigated. The aim of this study was to evaluate the anti-asthmatic potential of HD in an ovalbumin (OVA)-induced mouse model of allergic asthma. Moreover, the anti-inflammatory potential of HD was examined to identify a plausible mechanism of action of HD in vitro. HD strongly reduced goblet cell hyperplasia, eosinophil infiltration, and reactive oxygen species (ROS), which reduced airway hyperresponsiveness (AHR), inflammation, and the expression of Th2 cytokines (IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF). The expression of IL-5, IL-4, eotaxin-2, lysyl oxidase-like 2 (loxl2), and GATA-binding protein 3 (GATA-3) was attenuated in the lungs. In an in vitro assay, HD exerted immunomodulatory effects through the suppression of Th2 cytokines (IL-5, IL-13), IL-17, and tumor necrosis factor (TNF)-α production through downregulation of GATA-3 expression in EL-4 T cells. These findings suggest that the anti-asthmatic activity of HD may occur through the suppression of Th2 cytokines and total Immunoglobulin E (IgE) production by inhibition of the GATA-3 transcription pathway. Our results suggest that HD may be a potential alternative therapy, or a novel therapeutic traditional medicine, for the treatment of allergic asthma.

Interaction of Non-Specific Lipid-Transfer Proteins With Plant-Derived Lipids and Its Impact on Allergic Sensitization

Non-specific lipid-transfer proteins (nsLTPs) represent a family of ubiquitous plant proteins belonging to the prolamin superfamily. nsLTPs are characterized by a globular α-helical structure stabilized by four disulfide bonds and a hydrophobic cavity which acts as ligand-binding site for a broad spectrum of lipids and hydrophobic molecules. nsLTPs are involved in membrane biogenesis and in the adaption of plants to abiotic and biotic stress. They display antimicrobial activity by the ability to permeabilize the cell membrane of phytopathogens. Moreover, in the presence of lipids, nsLTPs are suggested to activate the plant immune system by a receptor-dependent mechanism. Additionally, nsLTPs from pollen and plant-derived food, in particular type 1 nsLTPs (9 kDa), are described as potent allergens. Within the nsLTP family Pru p 3 from peach is the clinically most relevant allergen which can cause genuine food allergy and frequently elicits severe clinical reactions. So far, the allergenic properties of nsLTPs are attributed to both their low molecular mass and their high thermal and proteolytic stability which allow them to reach the immune system in a biological intact form. Recently, the interaction of nsLTPs with lipids has been suggested to increase their allergenic properties and to promote the allergic sensitization to these proteins. This review will summarize the current knowledge on diversity of lipid ligands of plant LTPs, and illustrate recent studies performed with allergenic nsLTPs to investigate the effect of lipid binding on the structural modification and IgE-binding properties of proteins, and finally the potential effect on the innate immune responses.

Simple methods to reduce major allergens Ara h 1 and Ana o 1/2 in peanut and cashew extracts

Whole peanut or cashew extracts are usually used in immunotherapy. Reducing major allergen(s) in the extracts may lessen their side effects. Three methods were evaluated to reduce major allergens in peanut extracts: (1) p-aminobenzamidine; (2) magnetic agarose beads; and (3) extraction of a commercial peanut flour at pH 7, respectively. The first two methods were also used to reduce major allergens in cashew extracts. After treatments, samples were evaluated by SDS-PAGE. pABA-treated samples were also analyzed for IgE binding in western blot. We found that the methods resulted in peanut extracts lacking detectable Ara h 1 but containing Ara h 2/6 and cashew extract lacking Ana o 1/2, but containing Ana o 3. Consequently, reduced IgE binding was observed. We conclude that the methods are useful for producing peanut or cashew extract with little Ara h 1 or Ana o 1/2.