Abcg5

Cardiotonic pills (Batch no. 150203) and proUK (Batch no. 20170501) were supplied by Tasly Pharmaceutical Co., Ltd. (Tianjin, China). The processing of the product followed a strict quality control, and the ingredients were subjected to standardization.
Antibodies recognizing ATGL and GAPDH were from Cell Signaling Technology (Boston, MA, United States). Antibodies against CD36, SR-A, SR-BI, PPARα, ABCA1, ABCG1, ABCG5, andABCG8 were from Abcam (Cambridge, MA, United States). Oil Red O was from Sigma-Aldrich (St. Louis, MO, United States). All other reagents used in our study were of analytical grade.

Proximal jejunum tissue and Caco-2 cells were lysed using RIPA lysate and Phenylmethanesulfonyl fluoride (PMSF; Solarbio Life Sciences, Beijing, China) (100: 1). BCA detection kit (CWBIO, Beijing, China) detects protein concentration. Proteins were then separated on a 10% gel (20μg per lane) using sodium lauryl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE, Solarbio Co., Beijing, China) (120V, 90minutes). The relevant proteins were then transferred to a 0.45 μm polyvinylidene fluoride membrane (PVDF, Formex, Darmstadt, Germany). Thereafter, the membrane was blocked in Tris buffered saline solution containing 5% skimmed milk powder and 0.1% Tween-20 (TBS-T) at 20° C for 2 h, and then blocked with anti-LXRα, NPC1L1, ABCG5, ABCG8, ACAT2 and β-actin (1: 1000 dilution) (Abcam, Cambridge, UK) was gently shaken at 4° C overnight. The next day, the membrane was rinsed 3 times with TBS-T (10min each time) and incubated with horseradish peroxidase-conjugated secondary antibody (diluted to 1: 5000, Biosharp, Beijing, China) at room temperature for 2 h. Finally, protein bands were visualized by enhanced chemiluminescence (ECL; Merck Millipore, Darmstadt, Germany) and relative protein levels were quantified using Image Lab software.

Liver or aorta tissues were lysed in sample buffer containing 62 mM Tris–HCl, pH 6.8, 0.1% SDS, 0.1 mM sodium orthovanadate, and 50 mM sodium fluoride. The protein content was determined by the BCA protein assay (Applygen Technologies Inc., Beijing, China). Equal amount of proteins was loaded and separated by SDS-PAGE. After electrophoresis, the proteins were transferred on membranes, after being blocked with 3% non-fat dry milk, the membrane with target proteins was recognized with primary antibodies against CD36, SR-A, SR-BI, PPARα, ABCA1, ABCG1, ABCG5, ABCG8, and GAPDH (Abcam, Cambridge, MA, United States). The bands were detected using an ECL detection kit (Applygen Technologies, Beijing, China). For quantification, band intensity was assessed by densitometry and expressed as mean area density using Quantity One image analyzer software (Bio-Rad, Richmond, CA, United States).