scholarly journals The Role of Uptake and Efflux Transporters in the Disposition of Glucuronide and Sulfate Conjugates

2022 ◽  
Vol 12 ◽  
Author(s):  
Erkka Järvinen ◽  
Feng Deng ◽  
Wilma Kiander ◽  
Alli Sinokki ◽  
Heidi Kidron ◽  
...  

Glucuronidation and sulfation are the most typical phase II metabolic reactions of drugs. The resulting glucuronide and sulfate conjugates are generally considered inactive and safe. They may, however, be the most prominent drug-related material in the circulation and excreta of humans. The glucuronide and sulfate metabolites of drugs typically have limited cell membrane permeability and subsequently, their distribution and excretion from the human body requires transport proteins. Uptake transporters, such as organic anion transporters (OATs and OATPs), mediate the uptake of conjugates into the liver and kidney, while efflux transporters, such as multidrug resistance proteins (MRPs) and breast cancer resistance protein (BCRP), mediate expulsion of conjugates into bile, urine and the intestinal lumen. Understanding the active transport of conjugated drug metabolites is important for predicting the fate of a drug in the body and its safety and efficacy. The aim of this review is to compile the understanding of transporter-mediated disposition of phase II conjugates. We review the literature on hepatic, intestinal and renal uptake transporters participating in the transport of glucuronide and sulfate metabolites of drugs, other xenobiotics and endobiotics. In addition, we provide an update on the involvement of efflux transporters in the disposition of glucuronide and sulfate metabolites. Finally, we discuss the interplay between uptake and efflux transport in the intestine, liver and kidneys as well as the role of transporters in glucuronide and sulfate conjugate toxicity, drug interactions, pharmacogenetics and species differences.

2020 ◽  
Vol 23 ◽  
pp. 333-356
Author(s):  
Jéssica Veiga-Matos ◽  
Fernando Remião ◽  
Ana Motales

Transporters are large membrane proteins, which control the passage of various compounds through biological membranes. These proteins are divided into uptake and efflux transporters and play an important role in the toxicokinetics of many endobiotics and xenobiotics. The uptake transporters facilitate the absorption of these compounds from the blood into the proximal tubular cells, while the efflux transporters eliminate these compounds into tubular fluid (urine). Overall, the uptake is performed by the superfamily solute carrier (SLC) transporters, which are, mostly, located in the basolateral membrane. The organic anion transporters (OATs; SLC22), the organic cation transporters (OCTs; SLC22), the organic cation/carnitine transporters (OCTNs), and the organic anion transporting polypeptides (OATP; SLC21/SLCO) are some examples of uptake transporters of the SLC superfamily. On the other hand, the superfamily ATP-binding cassette (ABC) transporters carry out the elimination of the substances through the apical membrane of the proximal tubular cells. The multidrug resistance proteins 1 (MDR; ABCB), the multi resistance protein (MRP2; ABCC) and the breast cancer resistance protein (BCRP, ABCG) along with the multidrug and toxin extrusion (MATE), which is an SLC transporter, carry out the substance efflux of the cell, However, uptake transporters seem to be more efficient than efflux transporters, leading to an accumulation of compounds in proximal tubular cells and, consequently, to renal damage. The accumulation of compounds can also occur due to variations in the number of transporters that exist due to differences in sex, age, genetic polymorphisms and epigenetics. Furthermore, some substances can inhibit, induce or, eventually, activate these transporters, with consequent drug-drug interactions (DDIs) as a result of alterations on the toxicokinetics of xenobiotics, leading to an increase of their accumulation and, consequently, to renal damage. These compounds may be exogenous, such as antibiotics, antivirals, cisplatin, metals, herbicides, mycotoxins and drugs; or endogenous, like uric acid, bile acids, bilirubin conjugates and conjugated steroids. Thus, in this review, we will focus on the accumulation of exogenous compounds due to variations on renal transporters and the consequent biological effects caused by them.


Pharmaceutics ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 834
Author(s):  
Anima M. Schäfer ◽  
Henriette E. Meyer zu Schwabedissen ◽  
Markus Grube

The central nervous system (CNS) is an important pharmacological target, but it is very effectively protected by the blood–brain barrier (BBB), thereby impairing the efficacy of many potential active compounds as they are unable to cross this barrier. Among others, membranous efflux transporters like P-Glycoprotein are involved in the integrity of this barrier. In addition to these, however, uptake transporters have also been found to selectively uptake certain compounds into the CNS. These transporters are localized in the BBB as well as in neurons or in the choroid plexus. Among them, from a pharmacological point of view, representatives of the organic anion transporting polypeptides (OATPs) are of particular interest, as they mediate the cellular entry of a variety of different pharmaceutical compounds. Thus, OATPs in the BBB potentially offer the possibility of CNS targeting approaches. For these purposes, a profound understanding of the expression and localization of these transporters is crucial. This review therefore summarizes the current state of knowledge of the expression and localization of OATPs in the CNS, gives an overview of their possible physiological role, and outlines their possible pharmacological relevance using selected examples.


2013 ◽  
Vol 58 (3) ◽  
pp. 1294-1301 ◽  
Author(s):  
Matthew L. Rizk ◽  
Robert Houle ◽  
Grace Hoyee Chan ◽  
Mike Hafey ◽  
Elizabeth G. Rhee ◽  
...  

ABSTRACTRaltegravir (RAL) is a human immunodeficiency virus type 1 (HIV-1) integrase inhibitor approved to treat HIV infection in adults in combination with other antiretrovirals. The potential of RAL to cause transporter-related drug-drug interactions (DDIs) as an inhibitor has not been well described to date. In this study, a series ofin vitroexperiments were conducted to assess the inhibitory effects of RAL on major human drug transporters known to be involved in clinically relevant drug interactions, including hepatic and renal uptake transporters and efflux transporters. For hepatic uptake transporters, RAL showed no inhibition of organic anion-transporting polypeptide 1B1 (OATP1B1), weak inhibition of OATP1B3 (40% inhibition at 100 μM), and no inhibition of organic cation transporter 1 (OCT1). Studies of renal uptake transporters showed that RAL inhibited organic anion transporters 1 and 3 (OAT1 and OAT3) with 50% inhibitory concentrations (IC50s) (108 μM and 18.8 μM, respectively) well above the maximum concentration of drug in plasma (Cmax) at the clinical 400-mg dose and did not inhibit organic cation transporter 2 (OCT2). As for efflux transporters, RAL did not inhibit breast cancer resistance protein (BCRP) and showed weak inhibition of multidrug and toxin extrusion protein 1 (MATE1) (52% inhibition at 100 μM) and MATE2-K (29% inhibition at 100 μM). These studies indicate that at clinically relevant exposures, RAL does not inhibit or only weakly inhibits hepatic uptake transporters OATP1B1, OATP1B3, and OCT1, renal uptake transporters OCT2, OAT1, and OAT3, as well as efflux transporters BCRP, MATE1, and MATE2-K. The propensity for RAL to cause DDIs via inhibition of these transporters is therefore considered low.


Molecules ◽  
2018 ◽  
Vol 23 (12) ◽  
pp. 3062 ◽  
Author(s):  
Yuichi Uwai

Drug transporters mediate the absorption, tissue distribution, and excretion of drugs. The cDNAs of P-glycoprotein, multidrug resistance proteins (MRPs/ABCC), breast cancer resistance protein (BCRP/ABCG2), peptide transporters (PEPTs/SLC15), proton-coupled folate transporters (PCFT/SLC46A1), organic anion transporting polypeptides (OATPs/SLCO), organic anion transporters (OATs/SLC22), organic cation transporters (OCTs/SLC22), and multidrug and toxin extrusions (MATEs/SLC47) have been isolated, and their functions have been elucidated. Enantioselectivity has been demonstrated in the pharmacokinetics and efficacy of drugs, and is important for elucidating the relationship with recognition of drugs by drug transporters from a chiral aspect. Enantioselectivity in the transport of drugs by drug transporters and the inhibitory effects of drugs on drug transporters has been summarized in this review.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Songsong Wang ◽  
Xiao Xiao ◽  
Ao Li ◽  
Peng Li

An-Gong-Niu-Huang Wan (AGNH) has been a well-known cinnabar- and realgar-containing compound recipe for cerebral diseases. Unfortunately, its clinical practice is often restrained by the specific hepatorenal toxicity of cinnabar and realgar (C + R). In previous research studies, we have found that the antioxidative and anti-inflammatory effects of its herbal constituents could mitigate the risks from the toxicity. The underlying detoxification mechanisms are still unsolved. The present study investigated the protective effects of AGNH’s herbal constituents on hepatorenal injury induced by C + R. For the mice treated with C + R, the increased expression levels of sensitive biomarkers of metal exposure and hepatorenal toxicity, including metallothionein (MT) in both hepatorenal tissues and kidney induced molecule-1 (KIM-1) in the kidney, were simultaneously reduced when C + R coadministered with other herbal medicines. In addition, the contents of trivalent As (AsIII), pentavalent As (Asv), and mercury (Hg) in hepatorenal tissues of mice were also significantly reduced benefiting from the herbal constituents in AGNH. Further mechanism studies showed that the herbal constituents in AGNH could downregulate the expressions of uptake transporters (AQP9 and OAT1) and upregulate the expressions of efflux transporters (P-gp, MRP2, and MRP4) in mice intoxicated by C + R. Our results suggested that AGNH’s herbal constituents protect the body against C + R-induced hepatorenal toxicity and accumulations of Hg and As, which could be associated with the reestablishment of heavy metal homeostasis and the detoxification system.


2021 ◽  
Vol 22 ◽  
Author(s):  
Yabin Duan ◽  
Junbo Zhu ◽  
Jianxin Yang ◽  
Wenqi Gu ◽  
Xue Bai ◽  
...  

Background: Hypoxia has a negative effect on the cardiovascular system, nervous system, and metabolism, which contributes to potential changes in drug absorption, distribution, metabolism, and excretion (ADME). However, hypoxia can also alter the expression of microRNA (miRNA), thereby regulating drug-metabolizing enzymes, transporters, and ADME genes, such as hypoxia-inducible factor, inflammatory cytokine, nuclear receptor, etc. Therefore, it is crucial to study the role of miRNA in the regulation of drug-metabolizing enzymes and transporters under hypoxia. Methods: A systematic review of published studies was carried out to investigate the role of miRNA in the regulation of drug-metabolizing enzymes and transporters under hypoxia. Data and information on expression changes in miRNA, drug-metabolizing enzymes, and transporters under hypoxia were analyzed and summarized Results: Hypoxia can up- or down-regulate the expression of miRNA. The effect of hypoxia on Cytochrome P450 (CYP450) is still a subject of debate. The widespread belief is that hypoxia decreased the activity and expression of CYP1A1, CYP1A2, CYP2E1, and CYP3A1 and increased those of CYP3A6 and CYP2D1 in rats. Hypoxia increased the expression of a multidrug resistance-associated protein, breast cancer resistance protein, peptide transporter, organic cation transporter, and organic anion transporter. miRNA negatively regulated the expression of drug-metabolizing enzymes and transporters. Conclusion: The findings of this review indicated that miRNA plays a key role in the expression changes of drug-metabolizing enzymes and transporters under hypoxia.


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