Molecular Insights of Cholestasis in MDR2 Knockout Murine Liver Organoids.

MDR3 (multidrug resistance 3) deficiency in humans (MDR2 in mice) causes progressive familial intrahepatic cholestasis type 3 (PFIC3). PFIC3 is a lethal disease characterized by an early onset of intrahepatic cholestasis progressing to liver cirrhosis, a preneoplastic condition, putting individuals at risk of hepatocellular carcinoma (HCC). Hepatocyte-like organoids from MDR2-deficient mice (MDR2KO) were used in this work to study the molecular alterations caused by the deficiency of this transporter. Proteomic analysis by mass spectrometry allowed characterization of 279 proteins that were differentially expressed in MDR2KO compared with wild-type organoids. Functional enrichment analysis indicated alterations in three main cellular functions: (1) interaction with the extracellular matrix, (2) remodeling intermediary metabolism, and (3) cell proliferation and differentiation. The affected cellular processes were validated by orthogonal molecular biology techniques. Our results point to molecular mechanisms associated with PFIC3 that may drive the progression to liver cirrhosis and HCC and suggest proteins and cellular processes that could be targeted for the development of early detection strategies for these severe liver diseases.