Soybean glycinin- and β-conglycinin-induced intestinal immune responses in a murine model of allergy

ELISA Based Immunoreactivity Reduction of Soy Allergens through Thermal Processing

Allergens are proteins and are, therefore, likely to be denatured when subjected to thermal treatment. Traditional cooking has so far been able to reduce allergen sensitivity by around 70–90%. This study was aimed at evaluating the effect of a broad range of thermal treatments on the reduction of soy immunoreactivity (IR) in a 5% slurry using a sandwich ELISA technique. Cooking at 100 °C (10–60 min) and different thermal processing conditions, such as in commercial sterilization (with a process lethality (Fo) between 3 and 5 min) and selected severe thermal processing conditions (Fo > 5 and up to 23 min) were used in the study to evaluate their influence on allergen IR. Based on an IR comparison with an internal soy allergen standard, the allergen concentration in the untreated soy sample was calculated to be equivalent to 333 mg/kg (ppm). Cooking conditions only reduced the IR sensitivity to about 10 mg/kg (~1.5 log reductions), while the thermal processing treatments lowered the allergen IR up to 23 × 10−3 mg/kg (or 23 ppb) (>4 log reductions). FTIR analysis indicated significant changes in protein structure resulting from the thermal processing treatments, with a higher degree of allergen reduction corresponding with a higher value of random coil percentages. The influence of process severity on color and rheological properties was, however, minimal.

A popular fermented soybean food of Northeast India exerted promising antihyperglycemic potential via stimulating PI3K/AKT/AMPK/GLUT4 signaling pathways and regulating muscle glucose metabolism in type 2 diabetes

This study examined the antidiabetic efficacy of popular fermented soybean foods (FSF) of Northeast (NE) India. Results showed that among different FSF, aqueous extract of Hawaijar (AEH), a traditional FSF of Manipur, NE India, significantly augmented glucose utilization in cultured myotubes treated with high glucose (HG, 25 mM). Furthermore, AEH also upregulated glucose uptake, glucose-6-phosphate level, and phopho-PI3K/phospho-AKT/phospho-AMPK/GLUT4 protein expression in HG-treated myotubes. In vivo studies demonstrated that AEH supplementation (50, 100, or 200 mg/kg body weight/day, oral gavaging, 16 weeks) reduced body weight, fasting blood glucose, glycated hemoglobin, insulin resistance, and glucose intolerance in rats fed with high-fat diet (HFD). AEH supplementation stimulated phopho-PI3K/phospho-AKT/phospho-AMPK/GLUT4 signaling cascades involved in glucose metabolism of muscle tissues in diabetic rats. Chemical profiling of AEH (SDS-PAGE, immunoblotting, and HRMS) suggests the possible role of bioactive proteins/peptides and isoflavones underlying the antihyperglycemic potential AEH. Results from this study will be helpful for developing food-based prophylactics/therapeutics in managing hyperglycemia. PRACTICAL APPLICATIONS: Fermented soybean foods are gaining acceptance due to multiple health benefits. This study for the first time reports the antidiabetic potential of Hawaijar, an indigenous fermented soybean food of North-East India. Higher abundance of bioactive compounds (isoflavones and proteins/peptides) in Hawaijar may be responsible for the alleviation of impaired glucose metabolism associated with diabetes. The findings may be helpful for the development of a novel therapeutic to achieve better control of hyperglycemia and improve the lives of the patient population with diabetes.

11S Glycinin Up-Regulated NLRP-3-Induced Pyroptosis by Triggering Reactive Oxygen Species in Porcine Intestinal Epithelial Cells

11S glycinin is a major soybean antigenic protein, which induces human and animal allergies. It has been reported to induce intestinal porcine epithelial (IPEC-J2) cell apoptosis, but the role of pyroptosis in 11S glycinin allergies remains unknown. In this study, IPEC-J2 cells were used as an in vitro physiological model to explore the mechanism of 11S glycinin-induced pyroptosis. The cells were incubated with 0, 1, 5, and 10 mg·ml⁻¹ 11S glycinin for 24 h. Our results revealed that 11S glycinin significantly inhibited cell proliferation, induced DNA damage, generated active oxygen, decreased mitochondrial membrane potential, and increased the NOD-like receptor protein 3 (NLRP-3) expression of IPEC-J2 cells in a dose-dependent manner. Further, IPEC-J2 cells were transfected with designed sh-NLRP-3 lentivirus to silence NLRP-3. The results showed that 11S glycinin up-regulated the silenced NLRP-3 gene and increased the expression levels of apoptosis-related spot-like protein (ASC), caspase-1, the cleaved gasdermin D, and interleukin-1β. The IPEC-J2 cells showed pyrolysis morphology. Moreover, we revealed that N-acetyl-L-cysteine can significantly inhibit the production of reactive oxygen species and reduce the expression levels of NLRP-3 and the cleaved gasdermin D. Taken together, 11S glycinin up-regulated NLRP-3-induced pyroptosis by triggering reactive oxygen species in IPEC-J2 cells.

MHC II-PI3K/Akt/mTOR Signaling Pathway Regulates Intestinal Immune Response Induced by Soy Glycinin in Hybrid Grouper: Protective Effects of Sodium Butyrate

Soy glycinin (11S) is involved in immune regulation. As an additive, sodium butyrate (SB) can relieve inflammation caused by 11S. To further delve into the mechanisms. A diet containing 50% fishmeal was the control group (FM group), and the experimental groups consisted of the FM group baseline plus 2% glycinin (GL group), 8% glycinin (GH group), and 8% glycinin + 0.13% sodium butyrate (GH-SB group). The specific growth ratio (SGR), feed utilization, and density of distal intestinal (DI) type II mucous cells were increased in the GL group. In the serum, IFN-γ was significantly upregulated in the GL group, and IgG and IL-1β were upregulated in the GH group. IgG, IL-1β, and TNF-α in the GH-SB group were significantly downregulated compared to those in the GH group. The mRNA levels of mTOR C1, mTOR C2, and Deptor were upregulated in the GL, GH, and GH-SB groups in the DI compared with those in the FM group, while the mRNA levels of mTOR C1 and Deptor in the GH group were higher than those in the GL and GH-SB groups. 4E-BP1, RICTOR, PRR5, MHC II, and CD4 were upregulated in the GH group. TSC1, mLST8, and NFY mRNA levels in the GL and GH-SB groups were upregulated compared with those in the FM and GH groups. Western blotting showed P-PI3KSer294/T-PI3K, P-AktSer473/T-Akt, and P-mTORSer2448/T-mTOR were upregulated in the GH group. Collectively, our results demonstrate that low-dose 11S could improve serum immune by secreting IFN-γ. The overexpression of IgG and IL-1β is the reason that high-dose 11S reduces serum immune function, and supplementing SB can suppress this overexpression. Low-dose 11S can block the relationship between PI3K and mTOR C2. It can also inhibit the expression of 4E-BP1 through mTOR C1. High-dose 11S upregulates 4E-BP2 through mTOR C1, aggravating intestinal inflammation. SB could relieve inflammation by blocking PI3K/mTOR C2 and inhibiting 4E-BP2. Generally speaking, the hybrid grouper obtained different serum and DI immune responses under different doses of 11S, and these responses were ultimately manifested in growth performance. SB can effectively enhance serum immunity and relieve intestinal inflammation caused by high dose 11S.

Soybean glycinin impaired immune function and caused inflammation associated with PKC-ζ/NF-κb and mTORC1 signaling in the intestine of juvenile grass carp (Ctenopharyngodon idella)

Glycinin is a major protein and antinutritional factor of soybean. However, how dietary glycinin affect intestinal immune function of fish were largely unknown. In this study, we used juvenile grass carp as a model to investigate the impacts of glycinin on intestinal immune function of fish and involved mechanisms. We set three treatments including control, glycinin and glycinin + glutamine in this trial. For immune components, results revealed that compared with control group, glycinin group had lower acid phosphatase activities in the foregut, midgut and hindgut, lower C3 and C4 content, and lower mRNA abundances of IgM, IgZ, hepcidin, LEAP-2A, LEAP-2B and β-defensin-1 in the midgut and hindgut rather than foregut of grass carp. For pro-inflammatory cytokines and relevant signaling, glycinin elevated mRNA abundances of IL-1β, IL-8, IL-12p35, IL-12p40 and IL-17D in the midgut and IL-1β, IFN-γ2, IL-6, IL-8, IL-12p35, IL-12p40 and IL-17D in the hindgut, and increased protein abundances of PKC-ζ and nuclear NF-κB p65 in the midgut and hindgut in comparison to control. For anti-inflammatory cytokines and relevant signaling, glycinin reduced mRNA abundances of TGF-β1, TGF-β2, IL-4/13B (rather than IL-4/13A), IL-10 and IL-11 in the midgut and hindgut, and reduced p-mTOR (Ser 2448), p-S6K1 (Thr 389) and p-4EBP1 (Thr 37/46) protein abundances in the midgut and hindgut rather than foregut. Co-administration of glutamine with glycinin could partially enhance intestinal function and reduce intestinal inflammation compared with glycinin treatment. Concluded, glycinin decreased intestinal immune components and caused intestinal inflammation associated with PKC-ζ/NF-κB and mTORC1 signaling.

Sodium butyrate can improve intestinal integrity and immunity in juvenile Chinese mitten crab (Eriocheir sinensis) fed glycinin

Butyrate is a fermentation byproduct of gut microbiota and is susceptible to chronic oxidative stress. This study investigates the mitigative effects of sodium butyrate (SBT) on growth inhibition and intestinal damage induced by glycinin in juvenile Chinese mitten crab (Eriocheir sinensis). All four experimental diets containing 80 g/kg glycinin were formulated with 0, 10, 20 and 40 g/kg SBT respectively. There was no glycinin or SBT in the control diet. Juvenile crabs (0.33 ± 0.01g) were respectively fed with these five diets for eight weeks. The diets with 10 and 20 g/kg SBT significantly improved the survival and weight gain of the crabs compared with those in the 0 g/kg SBT group, and showed no difference with the control group. The crabs fed diets containing glycinin without SBT had lower glutathione and glutathione peroxidase activities but higher malondialdehyde in the intestine than those in the control group. Moreover, dietary glycinin decreased the lysozyme and phenoloxidase activities and improved the level of histamine in the intestine compared with the control group, while the supplementation of SBT counteracted these negative effects. The addition of SBT could also restore the impaired immunity and morphological structure of the intestine. Dietary SBT could increase the mRNA expression of antimicrobial peptides genes (anti-lipopolysaccharide factor 1 and 2) and decrease the content of pro-inflammatory factor TNF-α. The SBT could restore the intestinal microbial community disorganized by glycinin. The abundance of pathogenic bacteria (Aeromonas, Vibrio and Pseudomonas) decreased significantly and the potential probiotic bacteria (Bacillus, Lactobacillus, Chitinibacter and Dysgonomonas) increased significantly in the 10 g/kg SBT group. This study suggests that sodium butyrate supplementation can mitigate the negative effects induced by glycinin such as growth inhibition, intestinal inflammation and reduction of beneficial flora in the gut.

Effects of 7S and 11S on the intestine of weaned piglets after injection and oral administration of soybean antigen protein

Soybeans are used increasingly in food products because of their health benefits. In this study, we investigated the effect of soybean antigen protein on weaned piglet intestine. Seventy piglets were randomly divided into seven groups with 10 piglets each. At 7 and 14 days of age, groups A-C were injected with saline, and D-G were intramuscularly injected with or orally administered 7S or 11S. Groups B-G were artificially sensitized by dietary 7S or 11S. At 27 days, the small intestinal tissues were collected to determine levels of histamine, sIgA protein, and IgA mRNA. Histamine in B-G was significantly decreased in the duodenum and ileum. Moreover, sIgA expression was higher in all groups than in A, with B/C>D-G and F/G>D/E; the trend in IgA expression was similar. Collectively, these results indicated that soybean antigen protein-immunizing agents decrease sIgA and IgA levels. Additionally, the effect of injection immunization occurred prior to that of oral immunization.

Effects of glycinin and β-conglycinin on growth performance and intestinal health in juvenile Chinese mitten crabs (Eriocheir sinensis)

This study investigates the effects of two soybean antigens (glycinin and β-conglycinin) as an antinutritional substance in the diet on the growth, digestive ability, intestinal health and microbiota of juvenile Chinese mitten crabs (Eriocheir sinensis). The isonitrogenous and isolipidic diets contained two soybean antigens at two levels each (70 and 140 g/kg β-conglycinin, 80 and 160 g/kg glycinin) and a control diet without β-conglycinin or glycinin supplementation, and were used respectively to feed juvenile E. sinensis for seven weeks. Dietary inclusion of either glycinin or β-conglycinin significantly reduced crab survival and weight gain. The crabs fed diets containing soybean antigens had higher malondialdehyde concentrations and lower catalase activities in the intestine than those in the control. The activities of trypsin and amylase in the intestine were suppressed by dietary β-conglycinin and glycinin. Dietary glycinin or β-conglycinin impaired the immunity and morphological structure of intestine, especially the peritrophic membrane. The mRNA expression of constitutive and inducible immune responsive genes (lipopolysaccharide-induced TNF-α factor and interleukin-2 enhancer-binding factor 2) increased while the mRNA expression of the main genes related to the structural integrity peritrophic membrane (peritrophin-like gene and peritrophic 2) significantly decreased in the groups with soybean antigen addition. Soybean antigen could also change the intestinal microbial community. The abundance of pathogenic bacteria (Ochrobactrum, Burkholderia and Pseudomonas) increased significantly in both soybean antigen groups. Although pathogenic bacteria Vibrio were up-regulated in the glycinin group, the abundance of Dysgonomonas that degraded lignocellulose and ameliorated the gut environment decreased in the glycinin group. This study indicates that existence of soybean antigens (glycinin or β-conglycinin) could induce gut inflammation, reshape the community of gut microbiota, and cause digestive dysfunction, ultimately leading to impaired growth in crabs.

Soybean Glycinin- and β-Conglycinin-Induced Intestinal Damage in Piglets via the p38/JNK/NF-κB Signaling Pathway

β-Conglycinin (7S) and glycinin (11S) are known to induce a variety of hypersensitivity reactions involving the skin, intestinal tract, and respiratory tract. The present study aimed to identify the mechanism underlying the development of allergy to soybean antigen proteins, using piglets as an animal model. Weaned "Duroc × Landrace × Yorkshire" piglets were fed a diet supplemented with 7S or 11S to investigate the signaling pathway involved in intestinal damage in piglets. Results showed that serum nitric oxide (NO), tumor necrosis factor-α (TNF-α), and caspase-3 levels were significantly higher in 7S- and 11S-fed piglets compared to those in suckling or weaned ones. mRNA, protein, and phosphorylation levels of nuclear factor-kappa B (NF-κB), p38, and Jun N-terminal kinase (JNK) were higher in 7S- and 11S-fed piglets than in suckling and weaned ones. Overall, our results indicate that 7S and 11S damaged the intestinal function in piglets through their impact on NF-κB, JNK, and p38 expression.

Acidic polypeptides A1a, A3 and A4 of Gly m 6 (glycinin) are allergenic for piglets

Gly m 6 (glycinin) is one of the major antigenic proteins in soybeans responsible for transient hypersensitivity to soybean meal in weaned piglets. The globulin is a hexamer consisting of subunits containing basic and acidic polypeptides. Multiple acidic polypeptides have long been demonstrated to be allergens for humans and play a key role in the overall allergenicity of Gly m 6. To date, knowledge on the allergenicity of the acidic polypeptides for piglets is very limited. The purpose of this study was to identify the acidic polypeptides that were allergenic for piglets and to characterize these acidic polypeptides by ELISA, western blot, skin prick and basophile histamine release test. The IgG and IgE antibody binding capacities of the acidic polypeptides of Gly m 6 were determined using ELISA and western blot analysis with sera from Gly m 6 sensitized piglets. Skin prick test and basophile histamine release test were conducted to measure the effector cell response to the polypeptides. Specific IgG and IgE antibodies against A_1a, A₃ and A₄ of Gly m 6 were identified in the sera of Gly m 6 sensitized piglets. Meanwhile, positive skin prick test and specific histamine release responses were also induced by the acidic polypeptide A_1a, A₃ and A₄ of Gly m 6 from the basophiles of Gly m 6 sensitized piglets. The results demonstrate that the acidic polypeptide A_1a, A₃ and A₄ of Gly m 6 are allergenic for piglets.