The renal transport protein OATP4C1 mediates uptake of the uremic toxin asymmetric dimethylarginine (ADMA) and efflux of cardioprotective L-homoarginine

Journal article


Publication Details

Author(s): Taghikhani EP, Maas R, Fromm M, König J
Journal: PLoS ONE
Publication year: 2019
Volume: 14
Journal issue: 3
ISSN: 1932-6203


Abstract

Elevated plasma concentrations of the uremic toxin asymmetrical dimethylarginine (ADMA) and low plasma concentrations of L-homoarginine are independently associated with cardiovascular events and total mortality. Enzymes degrading ADMA [dimethylaminohydrolase 1 (DDAH1)] and synthesizing L-homoarginine [L-arginine:glycine amidinotransferase (AGAT)] are expressed in human proximal tubule cells. So far, it is not known which transport protein in the basolateral membrane of proximal tubule cells is mediating the uptake of ADMA into the cells for subsequent degradation or the export of intracellularly synthesized L-homoarginine. One study suggested that the uptake transporter OATP4C1 (gene symbol SLCO4C1) may be involved in the transport of ADMA and other uremic toxins. OATP4C1 is a member of the SLCO/SLC21 family of solute carriers, localized in the basolateral membrane of human proximal tubule cells. By using stably-transfected HEK cells overexpressing human OATP4C1, we demonstrate that ADMA and L-homoarginine are substrates of OATP4C1 with K-m values of 232.1 mu M and 49.9 mu M, respectively. ADMA and the structurally related uremic toxin SDMA (100 mu M) inhibited OATP4C1-mediated L-homoarginine uptake (P < 0.01), whereas other tested uremic toxins such as urea and p-cresyl sulfate have no effect on OATP4C1-mediated transport. Preloading experiments (300 mu M for 60 min) with subsequent efflux studies revealed that OATP4C1 also facilitates efflux e.g. of L-homoarginine. Both ADMA and L-homoarginine are substrates of human OATP4C1. Because proximal tubule cells are one site of ADMA metabolism and L-homoarginine synthesis, we postulate a protective role of OATP4C1 by mediating uptake of ADMA from and export of L-homoarginine into the systemic circulation.


FAU Authors / FAU Editors

Fromm, Martin Prof. Dr.
Lehrstuhl für Klinische Pharmakologie und Klinische Toxikologie
König, Jörg Prof. Dr.
Lehrstuhl für Klinische Pharmakologie und Klinische Toxikologie
Maas, Renke Prof. Dr.
Professur für Klinische Pharmakologie
Taghikhani, Emir Puyan
Lehrstuhl für Klinische Pharmakologie und Klinische Toxikologie


How to cite

APA:
Taghikhani, E.P., Maas, R., Fromm, M., & König, J. (2019). The renal transport protein OATP4C1 mediates uptake of the uremic toxin asymmetric dimethylarginine (ADMA) and efflux of cardioprotective L-homoarginine. PLoS ONE, 14(3). https://dx.doi.org/10.1371/journal.pone.0213747

MLA:
Taghikhani, Emir Puyan, et al. "The renal transport protein OATP4C1 mediates uptake of the uremic toxin asymmetric dimethylarginine (ADMA) and efflux of cardioprotective L-homoarginine." PLoS ONE 14.3 (2019).

BibTeX: 

Last updated on 2019-29-03 at 15:08