The role of Endothelial cell-derived Extracellular Vesicles in modulating Fibroblast Function in Skin Wound Healing

An adequate wound healing response requires the coordination of intercellular signals between multiple cell types. Following skin injury, endothelial cellsand fibroblasts provisionally replace the site of injury with newlyvascularized granulation tissue. Given the spatial and temporal overlap ofthese two cell types in the healing response, we hypothesize that endothelial cell-derived extracellular vesicles (ECEVs) could provide a communication pathway by which ECs influence fibroblast behavior. In this study we investigated the effects of ECEVs on fibroblast function both in vitro and in vivo through a murine skin wound healing model. Transcriptomic analysis showed that the uptake of ECEVs by fibroblasts altered functions and pathways relating to cel ldivision, ECM organization, and fibrosis. This transcriptomic analysis was functionally corroborated through in vitro assays in which fibroblasts demonstrated enhanced proliferation, migration, cell cycle progression,collagen contraction, and altered ECM deposition following ECEV treatment. Administration of ECEVs to healing mouse wounds led to greater collagen density and an upregulated fibroblast quantity in the wound bed of scar tissue. Our study highlights a novel role for ECEVs in affecting fibroblast function in the context of wound repair. Future studies can extrapolate this to other contexts where vascularization may affect tissue fibrosis. Overall design: RNA-sequencing (RNA-seq) profiling of primary human dermal fibroblasts treated with control media or control media containing endothelial cell-derived extracellular vesicles (ECEVs) for 72h.