Mechanisms of tissue factor induction by the uremic toxin indole-3 acetic acid through aryl hydrocarbon receptor/nuclear factor-kappa B signaling pathway in human endothelial cells.

Chronic kidney disease (CKD) is associated with high risk of thrombosis. Indole-3 acetic acid (IAA), an indolic uremic toxin, induces the expression of tissue factor (TF) in human umbilical vein endothelial cells (HUVEC) via the transcription factor aryl hydrocarbon receptor (AhR). This study aimed to understand the signaling pathways involved in AhR-mediated TF induction by IAA. We incubated human endothelial cells with IAA at 50 µM, the maximal concentration found in patients with CKD. IAA induced TF expression in different types of human endothelial cells: umbilical vein (HUVEC), aortic (HAoEC), and cardiac-derived microvascular (HMVEC-C). Using AhR inhibition and chromatin immunoprecipitation experiments, we showed that TF induction by IAA in HUVEC was controlled by AhR and that AhR did not bind to the TF promoter. The analysis of TF promoter activity using luciferase reporter plasmids showed that the NF-κB site was essential in TF induction by IAA. In addition, TF induction by IAA was drastically decreased by an inhibitor of the NF-κB pathway. IAA induced the nuclear translocation of NF-κB p50 subunit, which was decreased by AhR and p38MAPK inhibition. Finally, in a cohort of 92 CKD patients on hemodialysis, circulating TF was independently related to serum IAA in multivariate analysis. In conclusion, TF up-regulation by IAA in human endothelial cells involves a non-genomic AhR/p38 MAPK/NF-κB pathway. The understanding of signal transduction pathways related to AhR thrombotic/inflammatory pathway is of interest to find therapeutic targets to reduce TF expression and thrombotic risk in patients with CKD.

Combined microwave processing and enzymatic proteolysis of bovine whey proteins: the impact on bovine ß-lactoglobulin allergenicity.

The main aim of this study was to develop a continuous microwave treatment system of whey proteins and then apply this process at 37 °C, 50 °C, 65 °C and 70 °C to achieve pepsinolysis and produce extensively hydrolysed bovine whey protein hydrolysates with low allergenic properties. The microwave process was compared to a conventional thermal treatment with similar temperature set points. Both processes were deeply analysed in terms of the thermal kinetics and operating conditions. The pepsin hydrolysates obtained by the continuous microwave treatment and conventional heating were characterized by SDS-PAGE and RP-HPLC. The allergenicity of the whey protein hydrolysates was explored using a human IgE sensitized rat basophil leukaemia cell assay. The results indicate that extensively hydrolysed whey protein hydrolysates were obtained by microwave only at 65 °C and in a shorter time compared with the conventional thermal treatment. In the same temperature conditions under conventional heating, ß-lactoglobulin was resistant to pepsinolysis, and 37% of it remained intact. As demonstrated by an in vitro degranulation assay using specific human IgE-sensitized rat basophils, the extensively hydrolysed whey protein obtained by microwave showed maximum degranulation values of 6.53% compared to those of the native whey protein isolate (45.97%) and hence elicited no more allergenic reactions in basophils. This work emphasizes the potential industrial use of microwave heating specific to milk protein processing to reduce their allergenicity and improve their end-use properties.

Association of REL Polymorphism with Cow's Milk Proteins Allergy in Pediatric Algerian Population.

INTRODUCTION: Cow's milk proteins allergy (CMPA) pathogenesis involves complex immunological mechanisms with the participation of several cells and molecules involved in food allergy. The association of polymorphisms in the interleukin 4, Forkhead box P3 and the avian reticuloendotheliosis genes was investigated in an infant population with CMPA of Western Algeria. MATERIALS AND METHODS: We obtained DNA and clinical data from milk allergic subjects during active phase and from a group of non-atopic control subjects. RESULTS: Our findings showed that the allele G of the cRel gene intronic polymorphism at +7883 positions was significantly higher among cow's milk proteins allergic patients compared to control subjects. CONCLUSION: The results of this study suggest a possible association of CMPA with cRel G+7883T polymorphism.

Fermentation of Gluten by Lactococcus lactis LLGKC18 Reduces its Antigenicity and Allergenicity.

Wheat is a worldwide staple food, yet some people suffer from strong immunological reactions after ingesting wheat-based products. Lactic acid bacteria (LAB) constitute a promising approach to reduce wheat allergenicity because of their proteolytic system. In this study, 172 LAB strains were screened for their proteolytic activity on gluten proteins and α-amylase inhibitors (ATIs) by SDS-PAGE and RP-HPLC. Gliadins, glutenins, and ATI antigenicity and allergenicity were assessed by Western blot/Dot blot and by degranulation assay using RBL-SX38 cells. The screening resulted in selecting 9 high gluten proteolytic strains belonging to two species: Enterococcus faecalis and Lactococcus lactis. Proteomic analysis showed that one of selected strains, Lc. lactis LLGKC18, caused degradation of the main gluten allergenic proteins. A significant decrease of the gliadins, glutenins, and ATI antigenicity was observed after fermentation of gluten by Lc. lactis LLGKC18, regardless the antibody used in the tests. Also, the allergenicity as measured by the RBL-SX38 cell degranulation test was significantly reduced. These results indicate that Lc. lactis LLGKC18 gluten fermentation can be deeply explored for its capability to hydrolyze the epitopes responsible for wheat allergy.

Allergenicity of Fermented Foods: Emphasis on Seeds Protein-Based Products.

Food allergy is an IgE-mediated abnormal response to otherwise harmless food proteins, affecting between 5% and 10% of the world preschool children population and 1% to 5% adults. Several physical, chemical, and biotechnological approaches have been used to reduce the allergenicity of food allergens. Fermentation processes that contribute to technological and desirable changes in taste, flavor, digestibility, and texture of food products constitute one of these approaches. Lactic acid bacteria (LAB), used as starter cultures in dairy products, are a subject of increasing interest in fermentation of plant proteins. However, the studies designed to assess the impact of LAB on reduction of allergenicity of seed proteins are at an early stage. This review presents the current knowledge on food fermentation, with a focus on seed proteins that are increasingly used as ingredients, and its impacts on food potential allergenicity.