Journal: The Journal of Biological Chemistry

Article Title: Contribution of organic anion transporting polypeptides to bile acid uptake in the Caco-2 cell monolayer and gastrointestinal tract

doi: 10.1016/j.jbc.2026.111205

Figure Lengend Snippet: Screening for OATP-overexpressing HEK293T cells that mediate TC uptake. A , An overview of the experimental procedure. HEK293T cells were transfected with vectors containing cDNA of each of the nine OATP s or mock vectors. B – K , For validation of functional expression, estrone-3 sulfate (E3S), known as typical substrate, uptake assays were conducted for all OATPs, except OATP2A1 , OATP5A1 , and OATP6A1 , while prostaglandin E2 (PGE 2 ) uptake assays were conducted for OATP2A1 . For TC uptake assays, HEK293T cells transfected with each vector were exposed to uptake solutions (36 nM [ 3 H]-TC and 5 μM unlabeled TC) for 15 min at 37 °C. Assays were performed in either HBS-Hepes (pH 7.4) or HBS-Mes (pH 6.0). Values are presented as mean ± SD (n = 3–5). Statistical differences between mock-transfected cells (M) and OATP -transfected cells (O) were assessed using unpaired t test (∗ p < 0.05; ∗∗ p < 0.01; ∗∗∗ p < 0.001; ∗∗∗∗ p < 0.0001). The difference in TC uptake between pH 7.4 and pH 6.0 was evaluated by comparing relative TC uptake in OATP s cDNA-containing cells against mock-transfected cells for each pH, with statistical differences between pHs assessed using unpaired t test (## p < 0.01; #### p < 0.0001). cDNA, complementary DNA; OATP, organic anion-transporting polypeptide; TC, taurocholic acid.

Article Snippet: Sodium taurocholate and PGE 2 were sourced from Fujifilm Wako Pure Chemicals, with unlabeled estrone 3-sulfate purchased from Cayman Chemical Company.

Techniques: Transfection, Biomarker Discovery, Functional Assay, Expressing, Plasmid Preparation