PKD1 and renal fibrosis: We found that Pkd1-null cell EVs/exosomes could induce tubular dilation and small cyst formation as examined with MRI image and H&E staining (Supplementary Fig. 8a), and renal fibrosis as examined by picrosirius red and fibronectin staining (Supplementary Fig. 8b) in kidneys of Pkd1flox/+:Pkhd1-Cre mice but not those in kidneys from PBS-treated control mice.