PKD1 and cyst: We found that administration of Pkd1-null cell EVs/exosomes promoted cyst growth in kidneys from Pkd1RC/RC characterized by enlarged kidney size (Fig. 4a–c) and increased cystic index (Fig. 4d) and kidney weight/body weight (KW/BW) ratios (Fig. 4e) compared to those in kidneys from Pkd1RC/RC mice treated with PBS, PH2 cell-derived EVs/exosomes (Supplementary Fig. 5a-e) and mIMCD3 cell-derived EVs/exosomes (Supplementary Fig. 6a-g), respectively.