Project description:Food-specific IgE triggers life-threatening anaphylaxis; however, some people with food-specific IgE are asymptomatic upon allergen consumption. Using murine food allergy models, we discovered an unexpected pathway regulating the ability of food allergens to trigger anaphylaxis. C57BL/6 mice are uniquely resistant to anaphylaxis when challenged orally; we show that their gut barrier was impermeable to food allergens relative to anaphylaxis-susceptible strains, even prior to allergic sensitization. In a forward genetic screen, oral anaphylaxis resistance correlated with Dipeptidase1 (Dpep1) allelic variants. DPEP1 is expressed in intestinal epithelium and catabolizes leukotriene D4. Blocking DPEP1 with cilastatin enhanced allergen absorption in resistant mice. Conversely, pre-treatment of susceptible mice with a leukotriene synthesis inhibitor, zileuton, abrogated allergen absorption and subsequent oral anaphylaxis. Inhibiting leukotrienes may be a novel treatment for food allergy.
Project description:Food-specific IgE triggers life-threatening anaphylaxis; however, some people with food-specific IgE are asymptomatic upon allergen consumption. Using murine food allergy models, we discovered an unexpected pathway regulating the ability of food allergens to trigger anaphylaxis. C57BL/6 mice are uniquely resistant to anaphylaxis when challenged orally; we show that goblet cells transport less food allergens relative to anaphylaxis-susceptible strains, even prior to allergic sensitization. In a forward genetic screen, oral anaphylaxis resistance correlated with Dipeptidase1 (Dpep1) allelic variants. DPEP1 is expressed in intestinal epithelium and catabolizes leukotriene D4 (LTD4). Blocking DPEP1 with cilastatin, genetically deleting Dpep1, or oral administration of LTD4 enhanced allergen transport in resistant mice. Conversely, pre-treatment of susceptible mice with a leukotriene synthesis inhibitor, zileuton, abrogated allergen absorption from the gut and subsequent oral anaphylaxis. Inhibiting leukotrienes may be a novel treatment for food allergy.
Project description:Barrier integrity is central to the maintenance of a healthy immunological homeostasis. Impaired skin barrier function is linked with enhanced allergen sensitization and the development of diseases such as atopic dermatitis (AD), which can precede the development of other allergic diseases such as food allergies and asthma. Epidemiological evidence indicates that children suffering from allergies have lower levels of dietary fibre-derived short-chain fatty acids (SCFA). Using an experimental model of AD, we report that a fermentable fibre-rich diet alleviates AD severity and systemic allergen sensitization. The gut-skin axis underpins this phenomenon through SCFA, which strengthen skin barrier integrity by altering mitochondrial metabolism of epidermal keratinocytes. SCFA promote keratinocyte differentiation and the production of key structural lipids, resulting in enhanced barrier function. Our results demonstrate that dietary fibre and SCFA mitigate AD by improving barrier integrity, ultimately limiting early systemic allergen sensitization and development of disease.
