mRNA levels of UPR sensors and effectors in: (A) ADPLD cystic wall tissue (n=16) and healthy controls [liver (n=14), gallbladder (n=14), and NHC (n=4)], (B) normal (NHC; n=6) and cystic (ADPKD and ADPLD; n=6) human cholangiocytes in culture, (C) wild-type (n=20) and PCK rat (n=22) livers, and (D) normal (NRC; n=6) and cystic [PCK; n=6) rat cholangiocytes in culture. (E) Representative TEM images showing the ER ultrastructural morphology (red arrows) of normal and cystic cholangiocytes isolated from humans and rats. Scale bar= 0.5 μm. (F) Quantification of the ER lumen area in human [NHC (n=47), ADPKD (n=28), and ADPLD (n=28)] and rat [NRC (n=49) and PCK (n=52)] cholangiocytes.