Supplementary Methods and Figure Legends

Extracellular vesicles (EVs) contain RNA, protein, lipids, and other molecules from their parental cell type, which led to the hypothesis that urine-derived stem cell EVs (USC-EVS) could have potent regenerative effects in the setting of acute kidney injury (AKI). We tested this hypothesis in two different in vitro AKI models and an in vivo AKI model. To test USC-EVs ability to recover human kidney cells from nephrotoxicity, HK-2 human proximal tubular epithelial cell line and human kidney organoids derived from induced pluripotent stem cells were treated with 5 μM cisplatin for 48 h followed by 10 μg USC-EVs for 48 h. We next also tested USC-EVs in the unilateral nephrectomy followed by ischemia reperfusion model (UNIRI) AKI model to explore systemic effects in animals. USC-EV treatment of human kidney cells resulted in increased cellular proliferation (p ≤ 0.0001), decreased cytotoxicity (p