In this study, we investigated the delivery of synthetic neurosteroids into MCF-7 human breast adenocarcinoma cells via Organic Anionic Transporting Polypeptides (OATPs) (pH 7.4 and 5.5) to identify the structural components required for OATP-mediated cellular uptake and to get insight into brain drug delivery. Then, we identified structure-uptake relationships using in-house developed OATP1A2 homology model to predict binding sites and modes for the ligands. These binding modes were studied by molecular dynamics simulations to rationalize the experimental results. Our results show that carboxylic acid needs to be at least at 3 carbon-carbon bonds distance from amide bond at the C-3 position of the androstane skeleton and have an amino group to avoid efflux transport. Replacement of hydroxyl group at C-3 with any of the 3, 4, and 5-carbon chained terminal carboxylic groups improved the affinity. We attribute this to polar interactions between carboxylic acid and side-chains of Lys33 and Arg556. The additional amine group showed interactions with Glu172 and Glu200. Based on transporter capacities and efficacies, it could be speculated that the functionalization of acetyl group at the C-17 position of the steroidal skeleton might be explored further to enable OAT1A2-mediated delivery of neurosteroids into the cells and also across the blood-brain barrier.

• MeSH
• biologický transport MeSH
• hematoencefalická bariéra metabolismus   MeSH
• neurosteroidy * MeSH
• přenašeče organických aniontů * MeSH
• Publikační typ
• časopisecké články MeSH

To better understand the functionality of organic anion transporting polypeptides (OATPs) and to design new ligands, reliable structural data of each OATP is needed. In this work, we used a combination of homology model with molecular dynamics simulations to generate a comprehensive structural dataset, that encompasses a diverse set of OATPs but also their relevant conformations. Our OATP models share a conserved transmembrane helix folding harbouring a druggable binding pocket in the shape of an inner pore. Our simulations suggest that the conserved salt bridges at the extracellular region between residues on TM1 and TM7 might influence the entrance of substrates. Interactions between residues on TM1 and TM4 within OATP1 family shown their importance in transport of substrates. Additionally, in transmembrane (TM) 1/2, a known conserved element, interact with two identified motifs in the TM7 and TM11. Our simulations suggest that TM1/2-TM7 interaction influence the inner pocket accessibility, while TM1/2-TM11 salt bridges control the substrate binding stability.

• MeSH
• biologický transport MeSH
• přenašeče organických aniontů * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH

Inhibitory hydroxy-metylglutaryl koenzym A reduktázy (statiny) jsou jednou z nejvýznamnějších lékových skupin. Nejvýznamnější nejen stran zlepšení prognózy nemocných, ale i z pohledu masového užívání. Ač je léčba statiny obecně velmi dobře tolerována, občas se setkáme se statiny indukovanými myopatiemi. Ty mohou být zcela benigní a projeví se jen myalgiemi, méně často se objeví klinicky i laboratorně prokazatelná myopatie, jen vzácně se vyskytne i obávaná rhabdomyolýza. Analýza výskytu myopatií provázejících léčbu statiny ukazuje, že naprostá většina těchto nežádoucích účinků spadá na vrub lékových interakcí statinů s inhibitory jejich metabolizmu. Biodegradace jednotlivých statinů je odlišná. Simvastatin a lovastatin jsou metabolizovány izoenzymem CYP3A4, hydrofilnější atorvastatin je metabolizován jak oxidázou CYP3A4, tak přestupuje do jater membránovým transportním systémem organických aniontů (Organic Anion Transporting Protein – OATP). Fluvastatin je substrátem a mírným inhibitorem jiného izoenzymu – CYP2C9. Rosuvastatin a pravastatin není eliminován žádným z izoenzymů cytochromů P 450 (CYP), ale pouze systémem OATP. Největší potenciál k lékovým interakcím má lovastatin a symvastatin. Komedikace s řadou inhibitorů izoenzymu CYP3A4, jakými jsou makrolidová antibiotika klaritromycin či erytromycin, antimykotika, antiarytmikum amiodaron či blokátory kalciového kanálu verapamil či diltiazem, zvyšuje jejich expozici nemocným více než desetinásobně. Riziko interakce atorvastatinu díky duální cestě bioeliminace je výrazně nižší. Podobně fluvastatin má malý interakční potenciál, sám však může inhibovat degradaci warfarinu. Rosuvastatin a pravastatin jsou z pohledu lékových interakcí rovněž bezproblémové. Pouze inhibitory membránového transporotního systému OATP, jako je fibrát gemfibrozil či cyklosporin A, mohou hladinu významně zvyšovat.

• MeSH
• lékové interakce MeSH
• lidé MeSH
• nemoci svalů etiologie   chemicky indukované   MeSH
• přenašeče organických aniontů antagonisté a inhibitory   účinky léků   MeSH
• statiny farmakokinetika   metabolismus   škodlivé účinky   MeSH
• systém (enzymů) cytochromů P-450 farmakokinetika   metabolismus   účinky léků   MeSH
• Check Tag
• lidé MeSH

1. Some flavonoids contained in the common diet have been shown to interact with important membrane uptake transporters, including organic anion transporting polypeptides (OATPs). OATP2B1 and OATP1A2 expressed in the apical membrane of human enterocytes may significantly contribute to the intestinal absorption of drugs, e.g. statins. This study is aimed at an evaluation of the inhibitory potency of selected food honey flavonoids (namely galangin, myricetin, pinocembrin, pinobanksin, chrysin and fisetin) toward hOATP2B1 and hOATP1A2 as well as at examining their effect on the cellular uptake of the known OATP substrate rosuvastatin. 2. Cell lines overexpressing the hOATP2B1 or hOATP1A2 transporter were employed as in vitro model to determine the inhibitory potency of the flavonoids toward the OATPs. 3. Chrysin, galangin and pinocembrin were found to inhibit both hOATP2B1 and hOATP1A2 in lower or comparable concentrations as the known flavonoid OATP inhibitor quercetin. Galangin, chrysin and pinocembrin effectively inhibited rosuvastatin uptake by hOATP2B1 with IC50 ∼1-10 μM. The inhibition of the hOATP1A2-mediated transport of rosuvastatin by these flavonoids was weaker. 4. The found data indicate that several of the tested natural compounds could potentially affect drug cellular uptake by hOATP2B1 and/or hOATP1A2 at relative low concentrations, a finding which suggests their potential for food-drug interactions.

• MeSH
• biologické modely MeSH
• buňky MDCK MeSH
• dieta MeSH
• flavonoidy farmakologie   MeSH
• HEK293 buňky MeSH
• inhibiční koncentrace 50 MeSH
• lidé MeSH
• med * MeSH
• přenašeče organických aniontů antagonisté a inhibitory   metabolismus   MeSH
• psi MeSH
• rosuvastatin kalcium metabolismus   MeSH
• transfekce MeSH
• transport proteinů účinky léků   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Myricetin (MYR) and ampelopsin (AMP, or dihydromyricetin) are flavonoid aglycones found in certain plants and dietary supplements. During the presystemic biotransformation of flavonoids, mainly sulfate and glucuronide derivatives are produced, which are the dominant metabolites in the circulation. In this study, we tested the interactions of MYR, myricetin-3'-O-sulfate (M3'S), AMP, and ampelopsin-4'-O-sulfate (A4'S) with human serum albumin (HSA), cytochrome P450 enzymes (CYPs), and organic anion-transporting polypeptides (OATPs) using in vitro models, including the recently developed method for measuring flavonoid levels in living cells. M3'S and MYR bound to albumin with high affinity, and they showed moderate displacing effects versus the Site I marker warfarin. MYR, M3'S, AMP, and A4'S exerted no or only minor inhibitory effects on CYP2C9, CYP2C19, and CYP3A4 enzymes. M3'S and MYR caused considerable inhibitory actions on OATP1B1 at low micromolar concentrations (IC50 = 1.7 and 6.4 μM, respectively), while even their nanomolar levels resulted in strong inhibitory effects on OATP2B1 (IC50 = 0.3 and 0.4 μM, respectively). In addition, M3'S proved to be a substrate of OATP1B1 and OATP2B1. These results suggest that MYR-containing dietary supplements may affect the OATP-mediated transport of certain drugs, and OATPs are involved in the tissue uptake of M3'S.

• MeSH
• cytochrom P-450 CYP3A metabolismus   MeSH
• cytochrom P450 CYP2C9 metabolismus   MeSH
• flavonoidy * farmakologie   MeSH
• flavonoly farmakologie   MeSH
• lidé MeSH
• polypeptid C přenášející organické anionty * metabolismus   MeSH
• přenašeče organických aniontů * metabolismus   MeSH
• sérový albumin metabolismus   MeSH
• sírany metabolismus   MeSH
• systém (enzymů) cytochromů P-450 metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Membrane organic anion-transporting polypeptides (OATPs) are responsible for the drug transmembrane transport within the human body. The function of OATP2B1 transporter can be inhibited by various natural compounds. Despite increased research interest in soya as a part of human diet, the effect of its active components to interact with hOATP2B1 has not been elucidated in a complex extent. This in vitro study examined the inhibitory effect of main soy isoflavones (daidzin, daidzein, genistin, genistein, glycitin, glycitein, biochanin A, formononetin) and their metabolites formed in vivo (S-equol, O-desmethylangolensin) towards human OATP2B1 transporter. MDCKII cells overexpressing hOATP2B1 were employed to determine quantitative inhibitory parameters of the tested compounds and to analyze mechanism/s of the inhibitory interaction. The study showed that aglycones of soy isoflavones and the main biologically active metabolite S-equol were able to significantly inhibit hOATP2B1-mediated transport. The Ki values for most of aglycones range from 1 to 20 μM. In contrast, glucosides did not exhibit significant inhibitory effect. The kinetic analysis did not indicate a uniform type of inhibition towards the hOATP2B1 although predominant mechanism of inhibition seemed to be competitive. These findings may suggest that tested soy isoflavones and their metabolites might affect transport of xenobiotics including drugs across tissue barriers via hOATP2B1.

• MeSH
• buňky MDCK MeSH
• Glycine max * MeSH
• isoflavony farmakologie   MeSH
• kinetika MeSH
• přenašeče organických aniontů antagonisté a inhibitory   genetika   metabolismus   MeSH
• psi MeSH
• transfekce MeSH
• zvířata MeSH
• Check Tag
• psi MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• MeSH
• bilirubin sekrece   MeSH
• familiární hyperbilirubinemie etiologie   genetika   MeSH
• játra patologie   MeSH
• lidé MeSH
• mutace MeSH
• přenašeče organických aniontů genetika   metabolismus   nedostatek   MeSH
• Check Tag
• lidé MeSH

The aim of the present research was to study the uptake of DHEAS, and to establish the intracrine capacity of human platelets to produce sex steroid hormones. The DHEAS transport was evaluated through the uptake of [(3)H]-DHEAS in the presence or absence of different substrates through the organic anion transporting polypeptide (OATP) family. The activity of sulfatase enzyme was evaluated, and the metabolism of DHEAS was measured by the conversion of [(3)H]-DHEAS to [(3)H]-androstenedione, [(3)H]-testosterone, [(3)H]-estrone and [(3)H]-17beta-estradiol. Results indicated the existence in the plasma membrane of an OATP with high affinity for DHEAS and estrone sulphate (E(1)S). The platelets showed the capacity to convert DHEAS to active DHEA by the steroid-sulfatase activity. The cells resulted to be a potential site for androgens production, since they have the capacity to produce androstenedione and testosterone; in addition, they reduced [(3)H]-estrone to [(3)H]-17beta-estradiol. This is the first demonstration that human platelets are able to import DHEAS and E(1)S using the OATP family and to convert DHEAS to active DHEA, and to transform E(1)S to 17beta-estradiol.

• MeSH
• androgeny metabolismus   MeSH
• androstendion metabolismus   MeSH
• dehydroepiandrosteron metabolismus   MeSH
• dehydroepiandrosteronsulfát metabolismus   MeSH
• estradiol metabolismus   MeSH
• estron analogy a deriváty   metabolismus   MeSH
• lidé MeSH
• přenašeče organických aniontů metabolismus   MeSH
• testosteron metabolismus   MeSH
• trombocyty chemie   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Drug entry into the body of a helminth is a key factor in the efficacy of anthelmintics. The present project was designed to study the ex vivo uptake and efflux of the benzimidazole anthelmintic flubendazole (FLU) in four strains of H. contortus: the ISE strain (fully susceptible to anthelmintics), the ISE-S strain (resistant to ivermectin), the BR strain (resistant to benzimidazoles) and the WR strain (multi-resistant). The transport of FLU between dead and living nematodes was also compared as well as the effect of verapamil, an inhibitor of the main efflux ABCB1 transporter (P-glycoprotein), on FLU accumulation in nematodes. The obtained results showed that FLU is able to effectively enter H. contortus adults due to high FLU lipophilicity. Passive diffusion is probably the only mechanism in both FLU import and efflux from nematodes. No differences in FLU transport were found among four H. contortus strains with different sensitivity to anthelmintics. No active FLU efflux from H. contortus and no effect of verapamil were observed, indicating that H. contortus cannot protect itself against FLU by the active removal of this anthelmintic from its body.

• MeSH
• anthelmintika metabolismus   farmakokinetika   farmakologie   MeSH
• Haemonchus účinky léků   MeSH
• léková rezistence MeSH
• lékové interakce MeSH
• mebendazol analogy a deriváty   metabolismus   farmakokinetika   farmakologie   MeSH
• přenašeče organických aniontů antagonisté a inhibitory   MeSH
• verapamil farmakokinetika   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Primary renal hypouricemia is a genetic disorder characterized by defective renal uric acid (UA) reabsorption with complications such as nephrolithiasis and exercise-induced acute renal failure. The known causes are: defects in the SLC22A12 gene, encoding the human urate transporter 1 (hURAT1), and also impairment of voltage urate transporter (URATv1), encoded by SLC2A9 (GLUT9) gene. Diagnosis is based on hypouricemia (<119 μmol/L) and increased fractional excretion of UA (>10%). To date, the cases with mutations in hURAT1 gene have been reported in East Asia only. More than 100 Japanese patients have been described. Hypouricemia is sometimes overlooked; therefore, we have set up the flowchart for this disorder. The patients were selected for molecular analysis from 620 Czech hypouricemic patients. Secondary causes of hyperuricosuric hypouricemia were excluded. The estimations of (1) serum UA, (2) excretion fraction of UA, and (3) analysis of hURAT1 and URATv1 genes follow. Three transitions and one deletion (four times) in SLC22A12 gene and one nucleotide insertion in SLC2A9 gene in seven Czech patients were found. Three patients had acute renal failure and urate nephrolithiasis. In addition, five nonsynonymous sequence variants and three nonsynonymous sequence variants in SLC2A9 gene were found in two UK patients suffering from acute renal failure. Our finding of the defects in SLC22A12 and SLC2A9 genes gives further evidence of the causative genes of primary renal hypouricemia and supports their important role in regulation of serum urate levels in humans.

• MeSH
• diagnostické techniky a postupy MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• močové kameny diagnóza   genetika   MeSH
• mutace genetika   MeSH
• přenašeče organických aniontů genetika   MeSH
• proteiny přenášející organické kationty genetika   MeSH
• proteiny usnadňující transport glukosy genetika   MeSH
• senioři MeSH
• vrozené poruchy tubulárního transportu diagnóza   genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• senioři MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH