Recessive dystrophic epidermolysis bullosa (RDEB) is a rare skin disorder characterized by defects in collagen VII leading to a range of pathologies dominated by painful blister formation. Aberrant wound healing leads to fibrosis that contributes to life threatening cancers. We have developed an in vitro model of fibrotic extracellular matrix (ECM) produced by primary RDEB patient dermal fibroblasts, in which we use detachment of the cells’ matrix from plastic as a surrogate for fibrosis. This study first sought to determine the molecular mechanisms of matrix detachment, using Atomic Force Microscopy, total collagen assays, and measurements of gene and protein expression, and then assessed application of chemical compounds to reduce fibrosis. RDEB matrices were stiffer than non-RDEB, and treating fibroblasts with the pro-fibrotic cytokine TGFβ also increased tension. RDEB fibroblasts retain more collagen in the ECM compared to non-RDEB, and treating non-RDEB fibroblasts with TGFβ increased collagen retention in the ECM and accelerated detachment. To confirm these observations, we used a series of isogenic biopsies from an amputated leg of an RDEB patient to measure the molecular differences between fibrotic areas (tumor) compared to less fibrotic sites (peri-tumor and distal). Tumor fibroblasts detached faster than distal, and phosphorylated-ROCK2 and Collagen I were upregulated in more fibrotic areas, suggesting that these two markers contribute to detachment. Next, we assessed a number of compounds shown to be anti-fibrotic in other settings and identified that the ER Stress inhibitor Salubrinal delayed detachment. In conclusion, our detachment assay recapitulates fibrotic phenotypes and detachment is mediated by a combination of matrix tension, aberrant collagen secretion, and increased cell contractility. We are performing high throughput screens to identify FDA-approved drugs that can be repurposed for fibrosis prevention in RDEB.

ESDR593 - Preventing fibrosis in patients with recessive 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.