Advancement in Atopic Dermatitis Research Through the Use of a Novel Skin Tape Strip Mass Spectrometry Based Processing Protocol

Abstract

Allergic skin diseases, including Atopic Dermatitis (AD), severely impair the quality of life of affected patients. AD development is linked to a damaged skin barrier function that can precede clinical AD manifestations by many months. Currently there are no effective tools to predict the development of AD or to characterize the efficacy of applied therapy. Therefore, novel approaches to advance mechanistic understanding of AD as well as clinical management of AD and related skin diseases are needed.We have developed a novel protocol that allows the assessment of skin stratum corneum lipid species and filaggrin breakdown products using minimally invasive tape stripping in combination with liquid chromatography tandem mass spectrometry. Our approach requires only two tape strips to provide quantitative data on multiple lipid species as well as on the degradation products of filaggrin, a major skin protein responsible for skin barrier, pH and moisturizing properties. The hallmark of our approach is in the ability to normalize targeted mass spectrometric data per sample total protein content that was never done before. Our approach also allows to use the same sample for proteomics studies. We have applied our novel protocol to evaluate the difference between lesional and non‐lesional stratum corneum of AD subjects and to compare AD subjects with healthy individuals. The comparison of stratum corneum from 25 healthy adult subjects and 30 AD adult patients using our methodology confirmed previously known information about the shift towards short chain ceramide species in AD lesional skin and also revealed novel factors associated with AD development. Thus, total levels of sphingomyelins, and especially those with short chain fatty acids, were found to be increased several fold in atopic lesional skin. Furthermore, lysophosphatidylcholines demonstrated a profound redistribution towards the prevalence of short chain species not only in lesional but also in non‐lesional skin of AD subjects. These novel findings suggest a global shift in fatty acid biosynthesis that might be triggered by hyperactivated type 2 immune response. In fact, the RNAseq analysis performed on stratum corneum from same subjects revealed the downregulation of expression of fatty acid elongases ELOVL3 and ELOVL6 that may explain the observed global redistribution of the long chain and short chain lipids. Furthermore, the modeling of the effect of type 2 cytokines on sphingolipids using human differentiated keratinocytes in vitro confirmed the ability of type 2 cytokines IL‐4 and IL‐13 to provoke similar changes in sphingolipids. Our current ongoing studies further validate the power of the developed methodology and the value of lysophosphatidylcholines as biomarkers of atopic disease.In conclusion, skin tape stripping in conjunction with our unique processing protocol and targeted mass spectrometric methodology opens novel possibilities in clinical research by unveiling novel biomarkers of skin diseases and by allowing clinical studies in the skin using minimally invasive methodology.Support or Funding InformationNIH/NIAID grant U19 AI117673, NIH/NIAMS grant R01 AR41256This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.