This paper aims to develop an amperometric, non-enzymatic sensor for detecting and quantifying UA as an alert signal induced by allergens with protease activity in human cell lines (HEK293 and HeLa). Uric acid (UA) has been classified as a damage-associated molecular pattern (DAMP) molecule that serves a physiological purpose inside the cell, while outside the cell it can be an indicator of cell damage. Cell damage or stress can be caused by different health problems or by environmental irritants, such as allergens. We can act and prevent the events that generate stress by determining the extent to which cells are under stress. Amperometric calibration measurements were performed with a carbon paste electrode modified with La(OH)₃@MWCNT, at the potential of 0.3 V. The calibration curve was constructed in a linear operating range from 0.67 μM to 121 μM UA. The proposed sensor displayed good reproducibility with an RSD of 3.65% calculated for five subsequent measurements, and a low detection limit of 64.28 nM, determined using the 3 S/m method. Interference studies and the real sample analysis of allergen-treated cell lines proved that the proposed sensing platform possesses excellent sensitivity, reproducibility, and stability. Therefore, it can potentially be used to evaluate stress factors in medical research and clinical practice.

Although inflammation is primarily a protective response guarding the human body, it can result in a variety of chronic diseases such as allergies, auto-immune, cardiovascular diseases, and cancer. In NF-κB-mediated inflammation, many small molecules and food compounds characterized as nutraceuticals have shown positive effects associated with immunomodulatory properties. We investigated the effects of selected bioactive small molecules, commonly found in food components, vanillyl alcohol (VA) and lauric acid (LA), on different cell lines exposed to pro-inflammatory stimuli, lipopolysaccharide (LPS), and the food allergen actinidin (Act d 1). Pro-inflammatory cytokines were downregulated in response to both VA and LA, and this downregulation was caused by a decrease in the activation of the NF-κB pathway and the translocation of p65, the pathway’s major component. Small nutraceutical molecules, VA and LA, showed not only inhibition of the pro-inflammatory cytokines, but also inhibition of the NF-κB activation, and reduced translocation of the p65 component. The present study may contribute to the therapeutic use of these molecules for various inflammatory diseases, which have in common an increased expression of pro-inflammatory cytokines and NF-κB-mediated inflammation.

Activation of macrophages plays a key role in both inflammation and oxidative stress, key features of many chronic diseases. Pro-inflammatory M1-like macrophages, in particular, contribute to pro-oxidative environments and are a frequent focus of immunological research. This research examined the effects of kiwifruit allergen Act d 1, in comparison to LPS, on THP-1 macrophages in vitro differentiated under optimized conditions, both in the presence and in the absence of selected vanilloids. THP-1 monocyte differentiation was optimized by varying PMA exposure and resting time. Act d 1 induced M1-like phenotypic changes comparable to LPS, including upregulation of CD80, IL-1β and IL-6 secretion, gene expression of iNOS and NF-κB activation, in addition to increased reactive oxygen species (ROS) and catalase activity. Treatment with specific vanilloids mitigated these responses, primarily through reduced oxidative stress and NF-κB activation. Notably, vanillin (VN) was the most effective, also reducing CD80 expression and IL-1β levels. These results suggest that vanilloids can affect pro-inflammatory signaling and oxidative stress in THP-1 macrophages and highlight their potential to alter inflammatory conditions characterized by similar immune responses.

Food allergies are increasing worldwide, yet the early epithelial mechanisms that initiate allergic sensitization remain incompletely defined. As the intestinal epithelium governs both allergen translocation and epithelial–immune crosstalk, it constitutes a critical but underutilized model for predicting allergenicity. In this study, we used Caco-2 and T84 intestinal epithelial monolayers cultured on Transwell^® inserts to compare barrier properties and responses to peanut protein extract. Phenotypic characterization included biomarker profiling, transepithelial electrical resistance (TEER) measurements, tight junction integrity assessment, and analysis of cytokine levels as well as oxidative and nitrosative stress. Peanut exposure caused moderate TEER reductions without overt tight junction disruption while allowing translocation of the major allergen, Arachis hypogaea allergen 1 (Ara h 1), likely via transcellular pathways. Peanut protein extracts also induced epithelial stress responses, characterized by increased reactive oxygen species and nitric oxide production, alongside time-dependent secretion of innate and type 2-associated mediators, including IL-1β, TSLP, IL-25, and IL-33, indicating epithelial activation in the absence of complete barrier breakdown. Notably, basolateral supernatants from peanut-exposed epithelial monolayers activated THP-1-derived macrophages and enhanced IL-6 secretion, demonstrating that limited allergen passage across an otherwise intact epithelial barrier is sufficient to elicit early innate immune responses. Collectively, these findings indicate that peanut extract induce subtle functional perturbations in the intestinal epithelium while promoting downstream immune activation, highlighting Caco-2 and T84 cells as complementary in vitro platforms for studying barrier-dependent mechanisms of allergic sensitization.

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