Modeling junctional epidermolysis bullosa using tissue-engineered skin substitutes

Summary: Abstract Body: Junctional epidermolysis bullosa (JEB) is a rare genetic skin disorder with currently no curative treatment. It causes skin fragility and separation at the dermal-epidermal junction (DEJ) following minor trauma. Tissue-engineered skin substitute(s) (TES) produced with the self-assembly approach represent a useful model to study epidermolysis bullosa and, in combination with ex vivo gene therapy, could lead to the development of a treatment for JEB wounds. We believe that TES can be used to model the JEB phenotype in vitro. The objective of this study was to cultivate JEB skin cells and characterize the adhesion strength at the DEJ of TES produced with these human cells. We isolated and cultivated keratinocytes and fibroblasts from a JEB patient with a mutation in the gene of type XVII collagen (COL17A1). We produced TES with JEB cells or with healthy cells, and we measured the DEJ adhesion strength. Finally, we evaluated type XVII collagen expression in JEB keratinocytes and in TES by immunofluorescence labeling. TES with JEB keratinocytes had a low DEJ adhesion strength, regardless of whether fibroblasts were JEB (0,84mN/mm) or healthy (0,89mN/mm). TES produced with healthy keratinocytes had a high DEJ adhesion strength, with both healthy (5,54mN/mm) or JEB (6,13mN/mm) fibroblasts. Type XVII collagen was not expressed by JEB keratinocytes in 2D, or in TES with JEB keratinocytes. In conclusion, TES reproduced well the JEB phenotype, with a low DEJ adhesion strength and detachments at the DEJ. Our results indicated that only keratinocytes are involved in the production of the type XVII collagen at the DEJ. Therefore, the targeting of keratinocytes should be sufficient for the development of a gene therapy for JEB. Anne-Julie Bernier^{1, 2, 3}, Martin Barbier^{1, 2, 3}, Mbarka Bchetnia^{1, 2, 3}, Danielle Larouche^{1, 2, 3}, Mélissa Saber^{4, 5}, Lucie Germain^{1, 2, 3} 1. Centre de recherche en organogénèse expérimentale de l'Université Laval/LOEX, Québec, QC, Canada. 2. Surgery, Universite Laval Faculte de Medecine, Québec City, QC, Canada. 3. Regenerative Medicine Division, Centre de recherche du CHU de Québec-Université Laval, Québec, QC, Canada. 4. Centre Hospitalier de l'Universite de Montreal, Montreal, QC, Canada. 5. Medicine, Universite de Montreal, Montreal, QC, Canada. Stem Cell Biology, Tissue Regeneration and Wound Healing