In this study we aim to correct mutations within COL7A1 that cause malfunction, reduction or complete absence of type VII collagen in the skin’s basement membrane zone (BMZ), leading to dystrophic epidermolysis bullosa (DEB), a severe and rare skin blistering disease associated with a high risk of skin cancer as well as increased mortality. Therefore, we use a 3’-RTMS6m repair molecule to develop a safe, non-viral, non-invasive and efficient in vivo RNA therapy for DEB. This RTM-S6m, cloned into a non-viral minicircle-GFP vector, is capable to correct all mutations occurring between exon 65 and exon 108 of COL7A1 via a trans-splicing reaction between the repair molecule and the mutated mRNA. We tested the efficiency and specificity of the RTM in vitro in DEB keratinocytes and fibroblasts and confirmed correct trans-splicing on mRNA level via qPCR analysis, NGS as well as type VII collagen expression via immunofluorescence (IF) staining of transfected cells. Additionally we used a complex of 3’-RTMS6m with liposomes to deliver the RTMS6m onto DEB skin equivalents and were able to show a partial restoration of the type VII collagen expression at the BMZ, confirmed via IF staining of cryosections. Based on the conclusion that we can efficiently correct DEB keratinocytes and fibroblasts in an in vitro setting, we are aiming to analyze the functionality of the 3’-RTMS6m repair molecule in a DEB xenograft mouse model in vivo.

In this study we aim to correct mutations within _COL7A1_ that cause malfunction, reduction or complete absence of type VII collagen in the skin’s basement membrane zone (BMZ), leading to dystrophic epidermolysis bullosa (DEB), a severe and rare skin blistering disease associated with a high risk of skin cancer as well as increased mortality. Therefore, we use a 3’-RTMS6m repair molecule to develop a safe, non-viral, non-invasive and efficient in vivo RNA therapy for DEB. This RTM-S6m, cloned into a non-viral minicircle-GFP vector, is capable to correct all mutations occurring between exon 65 and exon 108 of _COL7A1_ via a trans-splicing reaction between the repair molecule and the mutated mRNA. We tested the efficiency and specificity of the RTM in vitro in DEB keratinocytes and fibroblasts and confirmed correct trans-splicing on mRNA level via qPCR analysis, NGS as well as type VII collagen expression via immunofluorescence (IF) staining of transfected cells. Additionally we used a complex of 3’-RTMS6m with liposomes to deliver the RTMS6m onto DEB skin equivalents and were able to show a partial restoration of the type VII collagen expression at the BMZ, confirmed via IF staining of cryosections. Based on the conclusion that we can efficiently correct DEB keratinocytes and fibroblasts in an in vitro setting, we are aiming to analyze the functionality of the 3’-RTMS6m repair molecule in a DEB xenograft mouse model in vivo.

ESDR287 - Development of a non-invasive, non-viral RNA therapy approach for dystrophic epidermolysis bullosa

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.