Studies of liver biopsy specimens obtained from the patients before and after 4PB therapy. (D) Histological characteristics of liver sections. Liver sections prepared from the liver biopsy specimens of the patients before and after the 4PB therapy were subjected to HE staining as described in Patients and Methods. A typical image under each condition is shown. Original magnification; 200×. (A-C) Analysis of mRNA and protein expression levels. cDNA (A), crude membrane fractions (B), and nuclear and cytosolic fractions (C) were prepared from liver biopsy specimens from the patients and then analyzed by qPCR (A) and immunoblotting (B and C) as described in Materials and Methods. In (A), the data were obtained from triplicate determination. Each bar represents the mean ± SE of individual specimens. In (B and C), the signal intensity of ATP8B1, BSEP, and FXR relative to that of NaKα1, LaminA, and EEA1 is presented below each panel. AU, arbitrary unit; P-gp, P-glycoprotein; P1, patient 1; P2, patient 2; P3, patient 3; 4PB(-), before 4PB treatment; 4PB(+), after 4PB treatment.