Several solute carrier proteins (SLC) are expressed in the intestine to absorb nutrients and xenobiotics. In spite of their physiological importance, carrier proteins have not been systematically employed as targets to increase oral drug bioavailability. The current proposal aims to close this gap by focusing on one of the few pharmacologically important transporters in the gastrointestinal tract: the human apical sodium-dependent bile acid transporter (hASBT). hASBT reabsorbs over 12 grams of bile acids daily, suggesting hASBT's tremendous capacity to serve as a drug or prodrug target for absorption. Preliminary data shows that drugs may be conjugated with a bile acid's C-24 carboxylate to yield prodrugs that are translocated by hASBT and increase drug bioavailability. Acyclovir's bioavailability was doubled in rats using a prodrug that targets hASBT. We hypothesize that a systematic structure-activity approach can be used to elucidate the chemistry space of the bile acid's C-24 side chain region that permits bile acid conjugates to be transported by hASBT.
The aim of this proposal is to develop a comprehensive and predictive three-dimensional quantitative structure-activity relationship (3D-QSAR) model for the hASBT substrate requirements of bile acid conjugates. 3D-QSAR development will be achieved by synthesizing several congeneric series of bile acid conjugates that systematically span a diverse chemistry space in the C-24 side chain region. Conjugates will be assayed for hASBT-mediated transport and inhibition using in vitro cell culture. A novel molecular modeling approach that considers conformation distribution patterns will be used in 3D-QSAR development. In vivo evaluation of selected bile acid conjugates will be performed in rats, to scale the in vitro 3D-QSAR model to an in vivo 3D-QSAR model. This proposal represents a chemistry-based approach to assess hASBT functioning and complements ongoing biophysical studies. The long-term goal of this research is to use the developed 3D-QSAR model to rationally select parent drugs and their resulting prodrugs for successful hASBT targeting. This systematic and progressive approach will serve as a prototypical method to elucidate the substrate requirements of other solute carrier (SLC) proteins.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK067530-03
Application #
7282045
Study Section
Xenobiotic and Nutrient Disposition and Action Study Section (XNDA)
Program Officer
Serrano, Jose
Project Start
2005-09-10
Project End
2010-08-31
Budget Start
2007-09-01
Budget End
2008-08-31
Support Year
3
Fiscal Year
2007
Total Cost
$264,713
Indirect Cost
Name
University of Maryland Baltimore
Department
Pharmacology
Type
Schools of Pharmacy
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Vivian, Diana; Polli, James E (2014) Mechanistic interpretation of conventional Michaelis-Menten parameters in a transporter system. Eur J Pharm Sci 64:44-52
González, Pablo M; Lagos, Carlos F; Ward, Weslyn C et al. (2014) Structural requirements of the human sodium-dependent bile acid transporter (hASBT): role of 3- and 7-OH moieties on binding and translocation of bile acids. Mol Pharm 11:588-98
Vivian, Diana; Polli, James E (2014) Synthesis and in vitro evaluation of bile acid prodrugs of floxuridine to target the liver. Int J Pharm 475:597-604
Claro da Silva, Tatiana; Polli, James E; Swaan, Peter W (2013) The solute carrier family 10 (SLC10): beyond bile acid transport. Mol Aspects Med 34:252-69
Vivian, Diana; Cheng, Kunrong; Khurana, Sandeep et al. (2013) Design and characterization of a novel fluorinated magnetic resonance imaging agent for functional analysis of bile Acid transporter activity. Pharm Res 30:1240-51
Kolhatkar, Vidula; Polli, James E (2012) Structural requirements of bile acid transporters: C-3 and C-7 modifications of steroidal hydroxyl groups. Eur J Pharm Sci 46:86-99
Kolhatkar, Vidula; Diao, Lei; Acharya, Chayan et al. (2012) Identification of novel nonsteroidal compounds as substrates or inhibitors of hASBT. J Pharm Sci 101:116-26
Ekins, Sean; Diao, Lei; Polli, James E (2012) A substrate pharmacophore for the human organic cation/carnitine transporter identifies compounds associated with rhabdomyolysis. Mol Pharm 9:905-13
Ekins, S; Polli, J E; Swaan, P W et al. (2012) Computational modeling to accelerate the identification of substrates and inhibitors for transporters that affect drug disposition. Clin Pharmacol Ther 92:661-5
González, Pablo M; Hussainzada, Naissan; Swaan, Peter W et al. (2012) Putative irreversible inhibitors of the human sodium-dependent bile acid transporter (hASBT; SLC10A2) support the role of transmembrane domain 7 in substrate binding/translocation. Pharm Res 29:1821-31

Showing the most recent 10 out of 37 publications