PKD1 and autosomal dominant polycystic kidney disease: We further found that treatment with ADPKD urinary exosomes decreased the expression of Pkd1 mRNA (Fig. 3f) but increased the phosphorylation of ERK, 4EBP, and S6 with no effect on the total protein levels of ERK, 4EBP, and S6 in IMCD3 cells compared to those cells treated with PBS (control) and normal urinary exosomes (Fig. 3g).