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.