Transport of fluorescent chenodeoxycholic acid via the human organic anion transporters OATP1B1 and OATP1B3

Abstract

This study sought to clarify the contributions of organic anion-transporting polypeptide (OATP) 1B1 and 1B3 to the liver uptake of chenodeoxycholic acid (CDCA). We synthesized a fluorescent version of CDCA, chenodeoxychilyl-(Ne-NBD)-lysine (CDCA-NBD), to characterize transportermediated uptake. CDCA-NBD is efficiently transported by OATP1B1 and OATP1B3 with high affinities. The MichaelisMenten constants for CDCA-NBD uptake by OATP1B1 and OATP1B3 were 1.45 6 0.39 mM and 0.54 6 0.09 mM, respectively. By confocal laser scanning microscopy, CDCA-NBD, which is taken up by OATP1B1 and OATP1B3, was observed to localize to the cytosol. We also examined the transport of newly synthesized fluorescent bile acids. NBDlabeled bile acids, including cholic acid, deoxycholic acid, lithocholic acid, and ursodeoxycholic acid, were all transported by OATP1B1 and OATP1B3. CDCA-NBD exhibited the highest rate of transport of the five NBD-labeled bile acids examined in OATP1B1-and OATP1B3-expressing cells. Our results suggest that OATP1B1 and OATP1B3 play important roles in CDCA uptake into the liver.

Organic Anion Transporting Polypeptide 1B1: a Genetically Polymorphic Transporter of Major Importance for Hepatic Drug Uptake

“…In addition, a fluorescently labeled derivative of chenodeoxycholic acid is transported by OATP1B1, suggesting that this primary bile acid is also an OATP1B1 substrate (Yamaguchi et al, 2006). OATP1B1 seems to represents the main sodium-independent uptake mechanism for bile acids in the liver.…”

“…Successfully developed fluorescent OATP1B1 marker substrates include fluorescently labeled cAMP, chenodeoxycholic acid, cholic acid derivates, and methotrexate (Yamaguchi et al, 2006;Annaert et al, 2010;Bednarczyk, 2010;de Waart et al, 2010;. Several compounds showing liver toxicity have been identified as OATP1B1 substrates, suggesting that OATP1B1 may play a role in their hepatotoxic effects.…”

Sodium fluorescein is a probe substrate for hepatic drug transport mediated by OATP1B1 and OATP1B3

“…Chenodeoxycholic acid was linked with fluorescent 7-nitrobenz-2-oxa-1,3-diazole and the uptake of this conjugate was characterized in HepG2 cells. 19 Tauro-nor-THCA-24-DBD was used to study bile salt export pump (BSEP) activities in membrane vesicles obtained from hBSEP-expressing Sf9 cells. 20 Finally, hepatic disposition of fluorescein-conjugated bile salts such as cholyl-glycylamido-fluorescein (CGamF) and cholyl-L-lysylfluorescein (CLF) have been characterized.…”

The emerging role of transport systems in liver function tests

“…CLF is not a substrate of the major bile salt transporters NTCP and bile salt export pump (BSEP), but of OATP1B3, weakly of OATP1B1, and of the efflux transporters MRP2 and MRP3 (table 1). Fluorescent chenodeoxycholic acid 7-nitrobenz-2-oxa-1,3-diazole is transported by OATP1B1 and OATP1B3 (Yamaguchi et al, 2006).…”