Post-burn hypertrophic scars are characterized by excessive accumulation of extracellular matrix secreted by fibroblasts. Exosomes are membrane lipid extracellular vesicles that play a pivotal role in cellular communication. Previous studies revealed the role of stem cell-derived exosomes in repairing damaged tissues, and also showed that cancer cell-derived exosomes could affect the disease pathogenesis. However, the functional properties of exosomes derived from hypertrophic scar fibroblasts (HTSFs) have not yet been studied extensively. In this study, we aimed to investigate whether HTSFs-derived exosomes can change the fibrosis-related signaling pathways in human normal fibroblasts (HNFs). HTSFs and HNFs were isolated from human hypertrophic scar tissues. HTSFs-derived exosomes were extracted and treated to HNFs. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to detect mRNA and protein expression, respectively, and cell proliferation and mobility were also assessed. Exosome treatment markedly increased cell proliferation and migration, and induced small mother against decapentaplegic (SMAD) signaling by increasing the levels of phosphorylated SMAD2 and SMAD1/5/8. The levels of TAK1 signaling components were also increased after exosome treatment to HNFs, including phosphorylated TAK1, p38, ERK, and JNK. HTSFs-derived exosomes further induced the epithelial-mesenchymal transition by decreasing the expression level of E-cadherin and increasing the expression levels of N-cadherin and vimentin. Consequently, the expression levels of fibronectin, type Ⅰ collagen, and type Ⅲ collagen were increased. Our results demonstrate the fibrotic property of HTSFs-derived exosomes, which suggests a potential functional role in hypertrophic scar development and a new therapeutic target.

P.014 Exosomes derived from human hypertrophic scar fibroblasts induces smad and TAK1 signaling in normal dermal fibroblasts

Dear friends and colleagues,

We will be pleased to welcome you in Turin (Italy) for the 19th European Burns Association´s Congress in 2022. Italy is honored to hold the meeting of the European Burns Association for the second time, after Verona in 1995. Turin is easily reachable from everywhere in Europe, either travelling by car, train or choosing flight connections. During the meeting, held in the renewed industrial center of the main Italian historical automotive factory (i.e. Lingotto-FIAT), we will meet international burn specialists, focusing on standards of care, progresses in burn treatment, strategies to face disaster situations, with a special attention to education of younger colleagues. However, in your spare time, you might enjoy the sweet days of Italian late summer, simply wandering in the green parks and gardens along the two rivers which cross the city, or you might decide to discover the numerous art galleries, churches, palaces, libraries, walking across elegant squares and large boulevards, passing through centuries of art and history; finally, you may choose to immerse yourself in some of the most exciting museum experiences, such as the Cinema Museum and the Turin’s Egyptian museum.

Looking forward to seeing you all in Turin for the 19th European Association´s Congress in 2022!
Maurizio Stella, Congress President, Turin Burn Centre