Skin Barrier Disrupted By Enzymatic Activity of House Dust Mite Extracts
Sunday, March 6, 2016
South Exhibit Hall H (Convention Center)
Lukas Einhorn, Kumiko Oida, Ina Herrmann, Susanne Vrtala, PhD, Yvonne Resch, Lucia Panakova, Gerlinde Hofstetter, MSc, BSc, Hiroshi Matsuda, Akane Tanaka, Erika Jensen-Jarolim, MD
Rationale: House dust mites (HDMs) can affect health and lead to the onset of allergic diseases in both humans and dogs in the shared living environment. Thus, we assessed a potential impact of HDMs on the canine epithelium in vitro by use of whole body extracts from Dermatophagoides pteronysinnus.

Methods: To examine the effect of HDM-derived proteases on the extracellular matrix (ECM), substrate gel zymography was performed. N-acetyl-b-glucosaminidase activities were colorimetrically detected with a chromogenic substrate. Using sera from allergic dogs, degranulation in response to the extracts was measured in canine mast cells to verify that the extracts can trigger allergic reactions.

Results: Enzymatic breakdown of casein (substrate for serine and cysteine protease) and gelatin (for collagenase) was observed regardless of the presence of Ca and Zn ions. The optimal pH for proteolysis was at neutral or alkaline pH, whereas effective in a wide range of temperature. In parallel, the extracts exerted N-acetyl-b-glucosaminidase activities, suggesting HDMs lead the potential for degrading the ECM proteoglycans. Moreover, the HDM extracts lead to degranulation of canine mast cells by incubation with serum from atopic dogs in an IgE dependent way.

Conclusions: Especially, when the acid mantle of the skin surface collapses due to inflammation or detergents, a consequent increase in the skin pH might facilitate the penetration of HDM allergens deep into the skin through several enzymatic activities.

Therefore, exposure to HDMs may play a causative role in the manifestation of epithelial barrier disruption.