Mechanisms of extracellular vesicle biogenesis that regulate wound healing

SUMMARY Resolution in skin wound healing is coordinated by intercellular communication processes that include extracellular vesicles (EVs) containing biologically active protein and nucleic acid. In injury models, EVs have been shown to be important mediators of tissue repair, although the mechanisms underlying the formation of specific EV subsets, loading of EV payloads, and cell- type specific EV uptake remain poorly understood. We address this knowledge gap with a comprehensive genetic approach to modify the regulation of EV biogenesis to change the EV Profile, Payload and Activity in cutaneous wound models that have well-defined biological relevance. We have recently established that genetic tools regulating EV biogenesis `re-program' EV payload. Moreover, over-expression of specific pro-reparative payloads that were identified by mass spectrometry can be engineered and delivered to promote resolution in models of impaired wound healing. With a focus on the discovery of novel EV mediators of crosstalk between immune and epithelial cells in the wound bed, we have focused on the biology of EVs in mediating intercellular signaling in EVs formation (Project 1-EV Biogenesis), the engineering of biologically active payloads (Project 2-EV Payloads), and identifying specific cell types that internalize EVs in the wound bed (Project 3-EV Uptake). Together, these Projects address the over-arching goals of creating therapeutic EVs with a systematic approach that is optimized for specific cell types based on an understanding of 1) How and where EVs are made?; 2) How EVs are loaded and whether they are biologically active ?; and 3) Which cells uptake EVs to promote durable tissue repair.