The Experts below are selected from a list of 34164 Experts worldwide ranked by ideXlab platform
Kenji Nishimura - One of the best experts on this subject based on the ideXlab platform.
-
Human liver specific organic anion transporter lst 1 mediates uptake of pravastatin by Human Hepatocytes
Journal of Pharmacology and Experimental Therapeutics, 2001Co-Authors: Daisuke Nakai, Rie Nakagomi, Yoshitake Furuta, Taro Tokui, Takaaki Abe, Toshihiko Ikeda, Kenji NishimuraAbstract:Involvement of LST-1 (a Human liver-specific transporter, also called OATP2) as the major transporter in the uptake of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, by Human liver was demonstrated. The hepatic uptake of pravastatin evaluated using Human Hepatocytes was Na+-independent and reached saturation with a Michaelis constant ( K m) of 11.5 ± 2.2 μM. The uptake of pravastatin was temperature-dependent and was inhibited by estradiol-17β-d-glucuronide, taurocholic acid, bromosulfophthalein, and simvastatin acid, but not by p -aminohippurate. Estradiol-17β-d-glucuronide competitively inhibited pravastatin uptake with an inhibition constant comparable to the K m value for estradiol-17β-d-glucuronide transport, indicating that a common transporter mediates the transport of pravastatin and estradiol-17β-d-glucuronide in Human Hepatocytes. The results obtained with Human Hepatocytes agreed with those obtained with LST-1 expressing Xenopus oocytes. Oocytes microinjected with Human liver polyadenylated mRNA showed Na+-independent uptake of pravastatin and estradiol-17β-d-glucuronide. A simultaneous injection of LST-1 antisense oligonucleotides completely abolished this uptake. Expression of LST-1 was immunohistochemically demonstrated in the Human Hepatocytes, but not in Hep G2 cells, which showed very low uptake of pravastatin. Therefore, LST-1 was regarded as a key molecule for pravastatin in liver-specific inhibition of cholesterol synthesis, making pravastatin accessible to the target enzyme, which would otherwise not be inhibited by this hydrophilic drug.
-
Human liver specific organic anion transporter lst 1 mediates uptake of pravastatin by Human Hepatocytes
Journal of Pharmacology and Experimental Therapeutics, 2001Co-Authors: Daisuke Nakai, Rie Nakagomi, Yoshitake Furuta, Taro Tokui, Takaaki Abe, Toshihiko Ikeda, Kenji NishimuraAbstract:Involvement of LST-1 (a Human liver-specific transporter, also called OATP2) as the major transporter in the uptake of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, by Human liver was demonstrated. The hepatic uptake of pravastatin evaluated using Human Hepatocytes was Na(+)-independent and reached saturation with a Michaelis constant (K(m)) of 11.5 +/- 2.2 microM. The uptake of pravastatin was temperature-dependent and was inhibited by estradiol-17beta-D-glucuronide, taurocholic acid, bromosulfophthalein, and simvastatin acid, but not by p-aminohippurate. Estradiol-17beta-D-glucuronide competitively inhibited pravastatin uptake with an inhibition constant comparable to the K(m) value for estradiol-17beta-D-glucuronide transport, indicating that a common transporter mediates the transport of pravastatin and estradiol-17beta-D-glucuronide in Human Hepatocytes. The results obtained with Human Hepatocytes agreed with those obtained with LST-1 expressing Xenopus oocytes. Oocytes microinjected with Human liver polyadenylated mRNA showed Na(+)-independent uptake of pravastatin and estradiol-17beta-D-glucuronide. A simultaneous injection of LST-1 antisense oligonucleotides completely abolished this uptake. Expression of LST-1 was immunohistochemically demonstrated in the Human Hepatocytes, but not in Hep G2 cells, which showed very low uptake of pravastatin. Therefore, LST-1 was regarded as a key molecule for pravastatin in liver-specific inhibition of cholesterol synthesis, making pravastatin accessible to the target enzyme, which would otherwise not be inhibited by this hydrophilic drug.
Markus Grompe - One of the best experts on this subject based on the ideXlab platform.
-
Frequent Aneuploidy Among Normal Human Hepatocytes
Gastroenterology, 2011Co-Authors: Andrew W. Duncan, Amy E. Hanlon Newell, Leslie Smith, Elizabeth M. Wilson, Susan B. Olson, Matthew J. Thayer, Stephen C. Strom, Markus GrompeAbstract:Murine Hepatocytes become polyploid and then undergo ploidy reversal and become aneuploid in a dynamic process called the ploidy conveyor. Although polyploidization occurs in some types of Human cells, the degree of aneuploidy in Human Hepatocytes is not known. We isolated Hepatocytes derived from healthy Human liver samples and determined chromosome number and identity using traditional karyotyping and fluorescence in situ hybridization. Similar to murine Hepatocytes, Human Hepatocytes are highly aneuploid. Moreover, imaging studies revealed multipolar spindles and chromosome segregation defects in dividing Human Hepatocytes. Aneuploidy therefore does not necessarily predispose liver cells to transformation but might promote genetic diversity among Hepatocytes.
-
Robust expansion of Human Hepatocytes in Fah^−/−/Rag2^−/−/Il2rg^−/− mice
Nature Biotechnology, 2007Co-Authors: Hisaya Azuma, Nicole K. Paulk, Aarati Ranade, Craig Dorrell, Muhsen Al-dhalimy, Ewa Ellis, Mark A. Kay, Stephen Strom, Milton Finegold, Markus GrompeAbstract:Mice that could be highly repopulated with Human Hepatocytes would have many potential uses in drug development and research applications. The best available model of liver Humanization, the uroplasminogen-activator transgenic model, has major practical limitations. To provide a broadly useful hepatic xenorepopulation system, we generated severely immunodeficient, fumarylacetoacetate hydrolase (Fah)-deficient mice. After pretreatment with a urokinase-expressing adenovirus, these animals could be highly engrafted (up to 90%) with Human Hepatocytes from multiple sources, including liver biopsies. Furthermore, Human cells could be serially transplanted from primary donors and repopulate the liver for at least four sequential rounds. The expanded cells displayed typical Human drug metabolism. This system provides a robust platform to produce high-quality Human Hepatocytes for tissue culture. It may also be useful for testing the toxicity of drug metabolites and for evaluating pathogens dependent on Human liver cells for replication.
-
Robust expansion of Human Hepatocytes in Fah −/− / Rag2 −/− / Il2rg −/− mice
Nature biotechnology, 2007Co-Authors: Hisaya Azuma, Stephen C. Strom, Nicole K. Paulk, Aarati Ranade, Craig Dorrell, Muhsen Al-dhalimy, Ewa Ellis, Mark A. Kay, Milton J. Finegold, Markus GrompeAbstract:Mice that could be highly repopulated with Human Hepatocytes would have many potential uses in drug development and research applications. The best available model of liver Humanization, the uroplasminogen-activator transgenic model, has major practical limitations. To provide a broadly useful hepatic xenorepopulation system, we generated severely immunodeficient, fumarylacetoacetate hydrolase (Fah)-deficient mice. After pretreatment with a urokinase-expressing adenovirus, these animals could be highly engrafted (up to 90%) with Human Hepatocytes from multiple sources, including liver biopsies. Furthermore, Human cells could be serially transplanted from primary donors and repopulate the liver for at least four sequential rounds. The expanded cells displayed typical Human drug metabolism. This system provides a robust platform to produce high-quality Human Hepatocytes for tissue culture. It may also be useful for testing the toxicity of drug metabolites and for evaluating pathogens dependent on Human liver cells for replication.
-
robust expansion of Human Hepatocytes in fah rag2 il2rg mice
Nature Biotechnology, 2007Co-Authors: Hisaya Azuma, Stephen C. Strom, Nicole K. Paulk, Aarati Ranade, Craig Dorrell, Ewa Ellis, Mark A. Kay, Milton J. Finegold, Muhsen Aldhalimy, Markus GrompeAbstract:Mice that could be highly repopulated with Human Hepatocytes would have many potential uses in drug development and research applications. The best available model of liver Humanization, the uroplasminogen-activator transgenic model, has major practical limitations. To provide a broadly useful hepatic xenorepopulation system, we generated severely immunodeficient, fumarylacetoacetate hydrolase (Fah)-deficient mice. After pretreatment with a urokinase-expressing adenovirus, these animals could be highly engrafted (up to 90%) with Human Hepatocytes from multiple sources, including liver biopsies. Furthermore, Human cells could be serially transplanted from primary donors and repopulate the liver for at least four sequential rounds. The expanded cells displayed typical Human drug metabolism. This system provides a robust platform to produce high-quality Human Hepatocytes for tissue culture. It may also be useful for testing the toxicity of drug metabolites and for evaluating pathogens dependent on Human liver cells for replication.
Olivier Fardel - One of the best experts on this subject based on the ideXlab platform.
-
Polarized location of SLC and ABC drug transporters in monolayer-cultured Human Hepatocytes.
Toxicology in Vitro, 2015Co-Authors: Marc Le Vee, Elodie Jouan, Bruno Stieger, Gregory Noel, Olivier FardelAbstract:Human Hepatocytes cultured in a monolayer configuration represent a well-established in vitro model in liver toxicology, notably used in drug transporter studies. Polarized status of drug transporters, i.e., their coordinated location at sinusoidal or canalicular membranes, remains however incompletely documented in these cultured Hepatocytes. The present study was therefore designed to analyze transporter expression and location in such cells. Most of drug transporters were first shown to be present at notable mRNA levels in monolayer-cultured Human Hepatocytes. Cultured Human Hepatocytes, which morphologically exhibited bile canaliculi-like structures, were next demonstrated, through immunofluorescence staining, to express the influx transporters organic anion transporting polypeptide (OATP) 1B1, OATP2B1 and organic cation transporter (OCT) 1 and the efflux transporter multidrug resistance-associated protein (MRP) 3 at their sinusoidal pole. In addition, the efflux transporters P-glycoprotein and MRP2 were detected at the canalicular pole of monolayer-cultured Human Hepatocytes. Moreover, canalicular secretion of reference substrates for the efflux transporters bile salt export pump, MRP2 and P-glycoprotein as well as sinusoidal drug transporter activities were observed. This polarized and functional expression of drug transporters in monolayer-cultured Human Hepatocytes highlights the interest of using this Human in vitro cell model in xenobiotic transport studies.
-
Regulation of drug transporter expression by oncostatin M in Human Hepatocytes.
Biochemical Pharmacology, 2011Co-Authors: Marc Le Vee, Elodie Jouan, Bruno Stieger, Valérie Lecureur, Olivier FardelAbstract:The cytokine oncostatin M (OSM) is a member of the interleukin (IL)-6 family, known to down-regulate expression of drug metabolizing cytochromes P-450 in Human Hepatocytes. The present study was designed to determine whether OSM may also impair expression of sinusoidal and canalicular drug transporters, which constitute important determinants of drug hepatic clearance. Exposure of primary Human Hepatocytes to OSM down-regulated mRNA levels of major sinusoidal solute carrier (SLC) influx transporters, including sodium-taurocholate co-transporting polypeptide (NTCP), organic anion transporting polypeptide (OATP) 1B1, OATP1B3, OATP2B1, organic cation transporter 1 and organic anion transporter 2. OSM also repressed mRNA expressions of ATP binding cassette (ABC) efflux transporters such as multidrug resistance protein (MRP) 2/ABCC2 and breast cancer resistance protein/ABCG2, without however impairing those of multidrug resistance gene 1/P-glycoprotein/ABCB1, MRP3/ABCC3, MRP4/ABCC4 and bile salt export pump/ABCB11. The cytokine concomitantly reduced NTCP, OATP1B1, OATP2B1 and ABCG2 protein expression and NTCP and OATP transport activities. OSM effects towards transporters were found to be dose-dependent and highly correlated with those of IL-6, but not with those of other inflammatory cytokines such as tumor necrosis factor-α or interferon-γ. In addition, OSM-mediated repression of some transporters such as NTCP, OATP1B1 and OATP2B1, was counteracted by knocking-down expression of the type II OSM receptor subunits through siRNA transfection. This OSM-mediated down-regulation of drug SLC transporters and ABCG2 in Human Hepatocytes may contribute to alterations of pharmacokinetics in patients suffering from diseases associated with increased production of OSM.
-
Differential regulation of drug transporter expression by hepatocyte growth factor in primary Human Hepatocytes.
Drug Metabolism and Disposition, 2009Co-Authors: Marc Le Vee, Bruno Stieger, Valérie Lecureur, Amélie Moreau, Olivier FardelAbstract:Hepatocyte growth factor (HGF) is known to down-regulate expression of drug-detoxifying proteins such as cytochromes P450 (P450s) in Human Hepatocytes. The present study was designed to determine whether HGF may also impair expression of uptake and efflux drug transporters, which constitute important determinants of the liver detoxification pathway, such as P450s. Exposure of primary Human Hepatocytes to 20 ng/ml HGF for 48 h was found to down-regulate mRNA levels of major sinusoidal uptake transporters, including sodium taurocholate-cotransporting polypeptide (NTCP), organic anion-transporting polypeptide (OATP) 2B1, OATP1B1, organic cation transporter (OCT) 1, and organic anion transporter 2. HGF concomitantly reduced NTCP, OATP2B1, and OATP1B1 protein expression and NTCP, OATP, and OCT1 transport activities. With respect to efflux pumps, HGF decreased mRNA expression of the canalicular bile salt export pump, whereas that of the multidrug resistance (MDR) 1 gene was transiently increased. Moreover, Western blot analysis indicated that HGF up-regulated expressions of MDR1/P-glycoprotein and breast cancer resistance protein in Human Hepatocytes, whereas those of multidrug resistance gene-associated protein (MRP) 2 and MRP3 were unchanged. However, HGF prevented constitutive androstane receptor-related up-regulation of MRP2 occurring in phenobarbital-treated Hepatocytes. Taken together, these data demonstrate that HGF differentially regulates transporter expression in Human Hepatocytes, i.e., it represses most of the sinusoidal uptake transporters, whereas expression of most of the efflux transporters is unchanged or increased. Such changes probably contribute to alterations of pharmacokinetics in patients with diseases associated with increased plasma levels of HGF such as fulminant hepatitis.
-
Down-regulation of organic anion transporter expression in Human Hepatocytes exposed to the proinflammatory cytokine interleukin 1beta.
Drug Metabolism and Disposition, 2008Co-Authors: Marc Le Vee, Bruno Stieger, Philippe Gripon, Olivier FardelAbstract:Interleukin (IL) 1beta is a proinflammatory cytokine known to markedly alter expression of major organic anion transporters in rodent Hepatocytes. However, its effects toward Human hepatic transporters remain poorly characterized. Therefore, the present study was aimed at determining IL-1beta effects on expression of organic anion transporters in primary Human Hepatocytes and highly differentiated Human hepatoma HepaRG cells. Exposure to 1 ng/ml IL-1beta was first shown to markedly repress mRNA expression of sodium-taurocholate cotransporting polypeptide (NTCP), a major sinusoidal transporter handling bile acids, in both Human Hepatocytes and HepaRG cells. It concomitantly reduced NTCP protein levels and NTCP-mediated cellular uptake of taurocholate in HepaRG cells. Other transporters such as the influx transporters organic anion transporting polypeptide (OATP)-B, OATP-C, and OATP8 and the efflux pumps multidrug resistance-associated protein (MRP) 2, MRP3, MRP4, and breast cancer resistance protein were also down-regulated at mRNA levels in Human Hepatocytes treated by IL-1beta for 24 h, and most of these transporters were similarly repressed in IL-1beta-exposed HepaRG cells; the cytokine also reduced bile salt export pump (BSEP) and OATP-C protein expression in Human Hepatocytes. IL-1beta was further shown to activate the extracellular signal-regulated protein kinase (ERK) in Human Hepatocytes and HepaRG cells; however, chemical inhibition of this kinase failed to counteract repressing effects of IL-1beta toward NTCP, BSEP, OATP-B, and OATP-C. Taken together, these data indicate that IL-1beta treatment reduced expression of major organic anion transporters in Human hepatic cells in an ERK-independent manner. Such IL-1beta effects may likely participate in both cholestasis and alterations of hepatic detoxification pathways caused by inflammation in Humans.
Daisuke Nakai - One of the best experts on this subject based on the ideXlab platform.
-
Human liver specific organic anion transporter lst 1 mediates uptake of pravastatin by Human Hepatocytes
Journal of Pharmacology and Experimental Therapeutics, 2001Co-Authors: Daisuke Nakai, Rie Nakagomi, Yoshitake Furuta, Taro Tokui, Takaaki Abe, Toshihiko Ikeda, Kenji NishimuraAbstract:Involvement of LST-1 (a Human liver-specific transporter, also called OATP2) as the major transporter in the uptake of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, by Human liver was demonstrated. The hepatic uptake of pravastatin evaluated using Human Hepatocytes was Na+-independent and reached saturation with a Michaelis constant ( K m) of 11.5 ± 2.2 μM. The uptake of pravastatin was temperature-dependent and was inhibited by estradiol-17β-d-glucuronide, taurocholic acid, bromosulfophthalein, and simvastatin acid, but not by p -aminohippurate. Estradiol-17β-d-glucuronide competitively inhibited pravastatin uptake with an inhibition constant comparable to the K m value for estradiol-17β-d-glucuronide transport, indicating that a common transporter mediates the transport of pravastatin and estradiol-17β-d-glucuronide in Human Hepatocytes. The results obtained with Human Hepatocytes agreed with those obtained with LST-1 expressing Xenopus oocytes. Oocytes microinjected with Human liver polyadenylated mRNA showed Na+-independent uptake of pravastatin and estradiol-17β-d-glucuronide. A simultaneous injection of LST-1 antisense oligonucleotides completely abolished this uptake. Expression of LST-1 was immunohistochemically demonstrated in the Human Hepatocytes, but not in Hep G2 cells, which showed very low uptake of pravastatin. Therefore, LST-1 was regarded as a key molecule for pravastatin in liver-specific inhibition of cholesterol synthesis, making pravastatin accessible to the target enzyme, which would otherwise not be inhibited by this hydrophilic drug.
-
Human liver specific organic anion transporter lst 1 mediates uptake of pravastatin by Human Hepatocytes
Journal of Pharmacology and Experimental Therapeutics, 2001Co-Authors: Daisuke Nakai, Rie Nakagomi, Yoshitake Furuta, Taro Tokui, Takaaki Abe, Toshihiko Ikeda, Kenji NishimuraAbstract:Involvement of LST-1 (a Human liver-specific transporter, also called OATP2) as the major transporter in the uptake of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, by Human liver was demonstrated. The hepatic uptake of pravastatin evaluated using Human Hepatocytes was Na(+)-independent and reached saturation with a Michaelis constant (K(m)) of 11.5 +/- 2.2 microM. The uptake of pravastatin was temperature-dependent and was inhibited by estradiol-17beta-D-glucuronide, taurocholic acid, bromosulfophthalein, and simvastatin acid, but not by p-aminohippurate. Estradiol-17beta-D-glucuronide competitively inhibited pravastatin uptake with an inhibition constant comparable to the K(m) value for estradiol-17beta-D-glucuronide transport, indicating that a common transporter mediates the transport of pravastatin and estradiol-17beta-D-glucuronide in Human Hepatocytes. The results obtained with Human Hepatocytes agreed with those obtained with LST-1 expressing Xenopus oocytes. Oocytes microinjected with Human liver polyadenylated mRNA showed Na(+)-independent uptake of pravastatin and estradiol-17beta-D-glucuronide. A simultaneous injection of LST-1 antisense oligonucleotides completely abolished this uptake. Expression of LST-1 was immunohistochemically demonstrated in the Human Hepatocytes, but not in Hep G2 cells, which showed very low uptake of pravastatin. Therefore, LST-1 was regarded as a key molecule for pravastatin in liver-specific inhibition of cholesterol synthesis, making pravastatin accessible to the target enzyme, which would otherwise not be inhibited by this hydrophilic drug.
Toshihiko Ikeda - One of the best experts on this subject based on the ideXlab platform.
-
Human liver specific organic anion transporter lst 1 mediates uptake of pravastatin by Human Hepatocytes
Journal of Pharmacology and Experimental Therapeutics, 2001Co-Authors: Daisuke Nakai, Rie Nakagomi, Yoshitake Furuta, Taro Tokui, Takaaki Abe, Toshihiko Ikeda, Kenji NishimuraAbstract:Involvement of LST-1 (a Human liver-specific transporter, also called OATP2) as the major transporter in the uptake of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, by Human liver was demonstrated. The hepatic uptake of pravastatin evaluated using Human Hepatocytes was Na+-independent and reached saturation with a Michaelis constant ( K m) of 11.5 ± 2.2 μM. The uptake of pravastatin was temperature-dependent and was inhibited by estradiol-17β-d-glucuronide, taurocholic acid, bromosulfophthalein, and simvastatin acid, but not by p -aminohippurate. Estradiol-17β-d-glucuronide competitively inhibited pravastatin uptake with an inhibition constant comparable to the K m value for estradiol-17β-d-glucuronide transport, indicating that a common transporter mediates the transport of pravastatin and estradiol-17β-d-glucuronide in Human Hepatocytes. The results obtained with Human Hepatocytes agreed with those obtained with LST-1 expressing Xenopus oocytes. Oocytes microinjected with Human liver polyadenylated mRNA showed Na+-independent uptake of pravastatin and estradiol-17β-d-glucuronide. A simultaneous injection of LST-1 antisense oligonucleotides completely abolished this uptake. Expression of LST-1 was immunohistochemically demonstrated in the Human Hepatocytes, but not in Hep G2 cells, which showed very low uptake of pravastatin. Therefore, LST-1 was regarded as a key molecule for pravastatin in liver-specific inhibition of cholesterol synthesis, making pravastatin accessible to the target enzyme, which would otherwise not be inhibited by this hydrophilic drug.
-
Human liver specific organic anion transporter lst 1 mediates uptake of pravastatin by Human Hepatocytes
Journal of Pharmacology and Experimental Therapeutics, 2001Co-Authors: Daisuke Nakai, Rie Nakagomi, Yoshitake Furuta, Taro Tokui, Takaaki Abe, Toshihiko Ikeda, Kenji NishimuraAbstract:Involvement of LST-1 (a Human liver-specific transporter, also called OATP2) as the major transporter in the uptake of pravastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, by Human liver was demonstrated. The hepatic uptake of pravastatin evaluated using Human Hepatocytes was Na(+)-independent and reached saturation with a Michaelis constant (K(m)) of 11.5 +/- 2.2 microM. The uptake of pravastatin was temperature-dependent and was inhibited by estradiol-17beta-D-glucuronide, taurocholic acid, bromosulfophthalein, and simvastatin acid, but not by p-aminohippurate. Estradiol-17beta-D-glucuronide competitively inhibited pravastatin uptake with an inhibition constant comparable to the K(m) value for estradiol-17beta-D-glucuronide transport, indicating that a common transporter mediates the transport of pravastatin and estradiol-17beta-D-glucuronide in Human Hepatocytes. The results obtained with Human Hepatocytes agreed with those obtained with LST-1 expressing Xenopus oocytes. Oocytes microinjected with Human liver polyadenylated mRNA showed Na(+)-independent uptake of pravastatin and estradiol-17beta-D-glucuronide. A simultaneous injection of LST-1 antisense oligonucleotides completely abolished this uptake. Expression of LST-1 was immunohistochemically demonstrated in the Human Hepatocytes, but not in Hep G2 cells, which showed very low uptake of pravastatin. Therefore, LST-1 was regarded as a key molecule for pravastatin in liver-specific inhibition of cholesterol synthesis, making pravastatin accessible to the target enzyme, which would otherwise not be inhibited by this hydrophilic drug.