P26 Identification of the pathways which drive myofibroblast transformation in hypertrophic scar fibroblasts

Abstract Introduction and aims Hypertrophic scars affect 91% of burn patients each year, and yet there is currently no effective treatment for their prevention. Myofibroblasts are key cells in the pathogenesis of hypertrophic scars, with many studies suggesting that inhibiting the transformation of resident dermal fibroblasts to myofibroblasts may be an effective preventive strategy. The aim of this project was to identify the key pathways that may be responsible for the transformation of myofibroblasts in hypertrophic scars. Methods Primary human fibroblasts were isolated from the scars of burn patients and were transformed to myofibroblasts using 10 ng mL−1 transforming growth factor (TGF)-β1. RNA was isolated from the cells using the Qiagen RNEasy kit. RNA sequencing (RNAseq) was carried out by Eurofins Genomics. Analysis of the data generated by RNAseq was conducted in-house at ARU using Reactome, DAVID and Kyoto Encyclopedia of Genes and Genomes (KEGG) software. Results RNAseq analysis identified 349 genes that were significantly differentially expressed between untreated and TGF-β1-treated fibroblasts. The top upregulated genes included several associated with extracellular matrix (ECM) production (e.g. COL10A1, COL11A1 and TGFB1), whereas the top downregulated genes were associated with maintaining the skin barrier integrity (e.g. PPL and TNXB) or ECM homeostasis (e.g. IGFBP5, CCN3 and ADAMTS15). Analysis using Reactome software identified 25 shared pathways among the expressed genes, of which 8 are directly linked to TGF-β1 signalling and potentially myofibroblast transformation. The analysis conducted using DAVID and KEGG software clustered genes together based on an enrichment score. The clusters that were highly enriched identified genes relating to cytokine–cytokine receptor interaction, platelet activation and cell cycle process. Conclusions We have identified the key pathways and genes that regulate the transformation of fibroblasts, isolated from hypertrophic scars, to myofibroblasts. It is envisaged that the pathways described here will lead to identification of novel targets for drug discovery, while improving our understanding of hypertrophic scar biology.