Induction of the multispecific organic anion transporter (cMoat/mrp2) gene and biliary glutathione secretion by the herbicide 2,4,5-trichlorophenoxyacetic acid in the mouse liver

1999 ◽  
Vol 341 (1) ◽  
pp. 105-111 ◽  
Author(s):  
Ana M. WIELANDT ◽  
Valeska VOLLRATH ◽  
Marlene MANZANO ◽  
Soledad MIRANDA ◽  
Luigi ACCATINO ◽  
...  
Keyword(s):  
Bile Acid ◽  
Bile Flow ◽  
Mouse Liver ◽  
Organic Anion ◽  
Fold Increase ◽  
Organic Anion Transporter ◽  
Peroxisome Proliferator ◽  
Mrna Levels ◽  
Anion Transporter ◽  
Trichlorophenoxyacetic Acid

The canalicular multispecific organic anion transporter, cMoat, is an ATP-binding-cassette protein expressed in the canalicular domain of hepatocytes. In addition to the transport of endo- and xenobiotics, cMoat has also been proposed to transport GSH into bile, the major driving force of bile-acid-independent bile flow. We have shown previously that the herbicide 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), a peroxisome-proliferator agent, significantly increases bile-acid-independent bile flow in mice. On this basis, the effect of the herbicide on cMoat gene expression was studied. A 3.6-fold increase in cMoat mRNA levels and a 2.5-fold increase in cMoat protein content were observed in the liver of mice fed on a diet supplemented with 0.125% 2,4,5-T. These effects were due to an increased rate of gene transcription (3.9-fold) and were not associated with peroxisome proliferation. Significant increases in bile flow (2.23±0.39 versus 1.13±0.15 μl/min per g of liver; P < 0.05) and biliary GSH output (7.40±3.30 versus 2.65±0.34 nmol/min per g of liver; P < 0.05) were observed in treated animals. The hepatocellular concentration of total glutathione also increased in hepatocytes of treated mice (10.95±0.84 versus 5.12±0.47 mM; P < 0.05), because of the induction (2.4-fold) of the heavy subunit of the γ-glutamylcysteine synthetase (GCS-HS) gene. This is the first model of co-induction of cMoat and GCS-HS genes in vivo in the mouse liver, associated with increased glutathione synthesis and biliary glutathione output. Our observations are consistent with the hypothesis that the cMoat transporter plays a crucial role in the secretion of biliary GSH.

scholarly journals Canalicular multispecific organic anion transporter/multidrug resistance protein 2 mediates low-affinity transport of reduced glutathione

1999 ◽  
Vol 338 (2) ◽  
pp. 393-401 ◽  
Author(s):  
Coen C. PAULUSMA ◽  
Michael A. van GEER ◽  
Raymond EVERS ◽  
Marc HEIJN ◽  
Roelof OTTENHOFF ◽  
...  
Keyword(s):  
Multidrug Resistance ◽  
Bile Flow ◽  
Organic Anion ◽  
Fold Increase ◽  
Organic Anion Transporter ◽  
Multidrug Resistance Protein ◽  
Wild Type ◽  
Anion Transporter ◽  
Mdckii Cells ◽  
Resistance Protein

The canalicular multispecific organic anion transporter (cMOAT), a member of the ATP-binding cassette transporter family, mediates the transport of a broad range of non-bile salt organic anions from liver into bile. cMOAT-deficient Wistar rats (TR-) are mutated in the gene encoding cMOAT, leading to defective hepatobiliary transport of a whole range of substrates, including bilirubin glucuronide. These mutants also have impaired hepatobiliary excretion of GSH and, as a result, the bile flow in these animals is reduced. In the present work we demonstrate a role for cMOAT in the excretion of GSH both in vivo and in vitro. Biliary GSH excretion in rats heterozygous for the cMOAT mutation (TR/tr) was decreased to 63% of controls (TR/TR) (114±24 versus 181±20 nmol/min per kg body weight). Madin-Darby canine kidney (MDCK) II cells stably expressing the human cMOAT protein displayed > 10-fold increase in apical GSH excretion compared with wild-type MDCKII cells (141±6.1 pmol/min per mg of protein versus 13.2±1.3 pmol/min per mg of protein in wild-type MDCKII cells). Similarly, MDCKII cells expressing the human multidrug resistance protein 1 showed a 4-fold increase in GSH excretion across the basolateral membrane. In several independent cMOAT-transfectants, the level of GSH excretion correlated with the expression level of the protein. Furthermore, we have shown, in cMOAT-transfected cells, that GSH is a low-affinity substrate for the transporter and that its excretion is reduced upon ATP depletion. In membrane vesicles isolated from cMOAT-expressing MDCKII cells, ATP-dependent S-(2,4-dinitrophenyl)glutathione uptake is competitively inhibited by high concentrations of GSH (Ki≈ 20 mM). We concluded that cMOAT mediates low-affinity transport of GSH. However, since hepatocellular GSH concentrations are high (5–10 mM), cMOAT might serve an important physiological function in maintenance of bile flow in addition to hepatic GSH turnover.

Human organic anion transporter 1B1 and 1B3 function as bidirectional carriers and do not mediate GSH-bile acid cotransport

2007 ◽  
Vol 293 (1) ◽  
pp. G271-G278 ◽  
Author(s):  
Chitrawina Mahagita ◽  
Steven M. Grassl ◽  
Pawinee Piyachaturawat ◽  
Nazzareno Ballatori
Keyword(s):  
Bile Acid ◽  
Transport Mechanism ◽  
Organic Anion ◽  
Large Family ◽  
Organic Anion Transporter ◽  
Xenopus Laevis Oocytes ◽  
Facilitated Diffusion ◽  
Transport Activity ◽  
Estrone Sulfate ◽  
Anion Transporter

Organic anion transporting polypeptides (OATP/ SLCO) are generally believed to function as electroneutral anion exchangers, but direct evidence for this contention has only been provided for one member of this large family of genes, rat Oatp1a1/Oatp1 ( Slco1a1). In contrast, a recent study has indicated that human OATP1B3/OATP-8 ( SLCO1B3) functions as a GSH-bile acid cotransporter. The present study examined the transport mechanism and possible GSH requirement of the two members of this protein family that are expressed in relatively high levels in the human liver, OATP1B3/OATP-8 and OATP1B1/OATP-C ( SLCO1B1). Uptake of taurocholate in Xenopus laevis oocytes expressing either OATP1B1/OATP-C, OATP1B3/OATP-8, or polymorphic forms of OATP1B3/OATP-8 (namely, S112A and/or M233I) was cis-inhibited by taurocholate and estrone sulfate but was unaffected by GSH. Likewise, taurocholate and estrone sulfate transport were trans-stimulated by estrone sulfate and taurocholate but were unaffected by GSH. OATP1B3/OATP-8 also did not mediate GSH efflux or GSH-taurocholate cotransport out of cells, indicating that GSH is not required for transport activity. In addition, estrone sulfate uptake in oocytes microinjected with OATP1B3/OATP-8 or OATP1B1/OATP-C cRNA was unaffected by depolarization of the membrane potential or by changes in pH, suggesting an electroneutral transport mechanism. Overall, these results indicate that OATP1B3/OATP-8 and OATP1B1/OATP-C most likely function as bidirectional facilitated diffusion transporters and that GSH is not a substrate or activator of their transport activity.

scholarly journals OATP1B3-1B7, a novel organic anion transporting polypeptide, is modulated by FXR ligands and transports bile acids

2019 ◽  
Vol 317 (6) ◽  
pp. G751-G762 ◽  
Author(s):  
Vanessa Malagnino ◽  
Janine Hussner ◽  
Ali Issa ◽  
Angela Midzic ◽  
Henriette E. Meyer zu Schwabedissen
Keyword(s):  
Endoplasmic Reticulum ◽  
Bile Acid ◽  
Bile Acids ◽  
Smooth Endoplasmic Reticulum ◽  
Organic Anion ◽  
Farnesoid X Receptor ◽  
Organic Anion Transporter ◽  
Organic Anion Transporting Polypeptide ◽  
Anion Transporter ◽  
Solute Carrier

Organic anion transporting polypeptide (OATP) 1B3–1B7 (LST-3TM12) is a member of the OATP1B [solute carrier organic anion transporter ( SLCO) 1B] family. This transporter is not only functional but also expressed in the membrane of the smooth endoplasmic reticulum of hepatocytes and enterocytes. OATP1B3–1B7 is a splice variant of SLCO1B3 in which the initial part is encoded by SLCO1B3, whereas the rest of the mRNA originates from the gene locus of SLCO1B7. In this study, we not only showed that SLCO1B3 and the mRNA encoding for OATP1B3–1B7 share the 5′ untranslated region but also that silencing of an initial SLCO1B3 exon lowered the amount of SLCO1B3 and of SLCO1B7 mRNA in Huh-7 cells. To validate the assumption that both transcripts are regulated by the same promoter we tested the influence of the bile acid sensor farnesoid X receptor (FXR) on their transcription. Treatment of Huh-7 and HepaRG cells with activators of this known regulator of OATP1B3 not only increased SLCO1B3 but also OATP1B3–1B7 mRNA transcription. Applying a heterologous expression system, we showed that several bile acids interact with OATP1B3–1B7 and that taurocholic acid and lithocholic acid are OATP1B3–1B7 substrates. As OATP1B3–1B7 is located in the smooth endoplasmic reticulum, it may grant access to metabolizing enzymes. In accordance are our findings showing that the OATP1B3–1B7 inhibitor bromsulphthalein significantly reduced uptake of bile acids into human liver microsomes. Taken together, we report that OATP1B3–1B7 transcription can be modulated with FXR agonists and antagonists and that OATP1B3–1B7 transports bile acids. NEW & NOTEWORTHY Our study on the transcriptional regulation of the novel organic anion transporting polypeptide (OATP) 1B3–1B7 concludes that the promoter of solute carrier organic anion transporter ( SLCO) 1B3 governs SLCO1B3–1B7 transcription. Moreover, the transcription of OATP1B3–1B7 can be modulated by farnesoid X receptor (FXR) agonists and antagonists. FXR is a major regulator in bile acid homeostasis that links OATP1B3–1B7 to this physiological function. Findings in transport studies with OATP1B3–1B7 suggest that this transporter interacts with the herein tested bile acids.

scholarly journals Dexamethasone induces an imbalanced fetal-placental-maternal bile acid circulation: involvement of placental transporters

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Wen Huang ◽  
Jin Zhou ◽  
Juanjuan Guo ◽  
Wen Hu ◽  
Guanghui Chen ◽  
...  
Keyword(s):  
Bile Acid ◽  
Organic Anion ◽  
Maternal Serum ◽  
Farnesoid X Receptor ◽  
Organic Anion Transporter ◽  
Cancer Resistance ◽  
Rat Serum ◽  
Altered Expression ◽  
Anion Transporter ◽  
Fetal Serum

Abstract Background The use of prenatal dexamethasone remains controversial. Our recent studies found that prenatal dexamethasone exposure can induce maternal intrahepatic cholestasis and have a lasting adverse influence on bile acid (BA) metabolism in the offspring. The purpose of this study was to investigate the effects of dexamethasone on fetal-placental-maternal BA circulation during the intrauterine period, as well as its placental mechanism. Methods Clinical data and human placentas were collected and analyzed. Pregnant Wistar rats were injected subcutaneously with dexamethasone (0.2 mg/kg per day) from gestational day 9 to 20. The metabolomic spectra of BAs in maternal and fetal rat serum were determined by LC-MS. Human and rat placentas were collected for histological and gene expression analysis. BeWo human placental cell line was treated with dexamethasone (20–500 nM). Results Human male neonates born after prenatal dexamethasone treatment showed an increased serum BA level while no significant change was observed in females. Moreover, the expression of organic anion transporter polypeptide-related protein 2B1 (OATP2B1) and breast cancer resistance protein (BCRP) in the male neonates’ placenta was decreased, while multidrug resistance-associated protein 4 (MRP4) was upregulated. In experimental rats, dexamethasone increased male but decreased female fetal serum total bile acid (TBA) level. LC-MS revealed that primary BAs were the major component that increased in both male and female fetal serum, and all kinds of BAs were significantly increased in maternal serum. The expression of Oatp2b1 and Bcrp were reduced, while Mrp4 expression was increased in the dexamethasone-treated rat placentas. Moreover, dexamethasone increased glucocorticoid receptor (GR) expression and decreased farnesoid X receptor (FXR) expression in the rat placenta. In BeWo cells, dexamethasone induced GR translocation into the nucleus; decreased FXR, OATP2B1, and BCRP expression; and increased MRP4 expression. Furthermore, GR was verified to mediate the downregulation of OATP2B1, while FXR mediated dexamethasone-altered expression of BCRP and MRP4. Conclusions By affecting placental BA transporters, dexamethasone induces an imbalanced fetal-placental-maternal BA circulation, as showed by the increase of primary BA levels in the fetal serum. This study provides an important experimental and theoretical basis for elucidating the mechanism of dexamethasone-induced alteration of maternal and fetal BA metabolism and for exploring early prevention and treatment strategies.

scholarly journals Identification of a Novel Organic Anion Transporter Mediating Carnitine Transport in Mouse Liver and Kidney

2010 ◽  
Vol 25 (4-5) ◽  
pp. 511-522 ◽  
Author(s):  
Hiroki Tsuchida ◽  
Naohiko Anzai ◽  
Ho Shin ◽  
Michael Wempe ◽  
Promsuk Jutabha ◽  
...  
Keyword(s):  
Mouse Liver ◽  
Organic Anion ◽  
Organic Anion Transporter ◽  
Anion Transporter ◽  
Carnitine Transport ◽  
Liver And Kidney

scholarly journals Sex-Differences in Renal Expression of Selected Transporters and Transcription Factors in Lean and Obese Zucker Spontaneously Hypertensive Fatty Rats

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Andrea Babelova ◽  
Birgitta C. Burckhardt ◽  
Waja Wegner ◽  
Gerhard Burckhardt ◽  
Maja Henjakovic
Keyword(s):  
Transcription Factors ◽  
Organic Anion ◽  
Organic Anion Transporter ◽  
Kidney Cortex ◽  
Mrna Levels ◽  
Spontaneously Hypertensive ◽  
Anion Transporter ◽  
Tubular Lumen ◽  
Pas Staining ◽  
Obese Male

The aim of this study was to identify sex-dependent expression of renal transporter mRNA in lean and obese Zucker spontaneously hypertensive fatty (ZSF1) rats and to investigate the interaction of the most altered transporter, organic anion transporter 2 (Oat2), with diabetes-relevant metabolites and drugs. Higher incidence of glomerulosclerosis, tubulointerstitial fibrosis, and protein casts in Bowman’s space and tubular lumen was detected by PAS staining in obese male compared to female ZSF1 rats. Real-time PCR on RNA isolated from kidney cortex revealed that Sglt1-2, Oat1-3, and Oct1 were higher expressed in kidneys of lean females. Oct2 and Mrp2 were higher expressed in obese males. Renal mRNA levels of transporters were reduced with diabetic nephropathy in females and the expression of transcription factors Hnf1βand Hnf4αin both sexes. The highest difference between lean and obese ZSF1 rats was found for Oat2. Therefore, we have tested the interaction of human OAT2 with various substances using tritium-labeled cGMP. Human OAT2 showed no interaction with diabetes-related metabolites, diabetic drugs, and ACE-inhibitors. However, OAT2-dependent uptake of cGMP was inhibited by furosemide. The strongly decreased expression of Oat2 and other transporters in female diabetic ZSF1 rats could possibly impair renal drug excretion, for example, of furosemide.

scholarly journals P0946OXIDATIVE STRESS AND HEME METABOLISM IN RED BLOOD CELLS FROM HEMODIALYSIS PATIENTS

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Gabriela Ferreira Dias ◽  
Gabriela Bohnen ◽  
Nadja Grobe ◽  
Xia Tao ◽  
Roberto Pecoits-Filho ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Organic Anion ◽  
Fold Increase ◽  
Organic Anion Transporter ◽  
Ros Generation ◽  
Heme Oxygenase 1 ◽  
Anion Transporter ◽  
Before And After

Abstract Background and Aims We have previously described that indoxyl sulfate promotes red blood cells (RBC) ROS generation through organic anion transporter 2 as well as NADPH oxidase activity-dependent and GSH-independent mechanisms (Dias et al., 2018). However, there is little information regarding pathways of antioxidant balance to protect RBC from extensive oxidative stress that occurs during hemodialysis (HD). Intracellular free heme is degraded by Heme Oxygenase 1 (HO-1), which is regarded as the major cytoprotective enzyme (Maines, 1988; Gozzelino et al., 2010). In the current study, we assessed HO-1 activity and ROS production in RBC from healthy subjects and hemodialysis (HD) patients before and after HD. Method Blood was drawn from 6 healthy individuals (CON-RBC) and 6 HD patients (HD-RBC) before (pre/HD-RBC) and after high flux HD (post/HD-RBC). Isolated RBC were stained with DCFH-DA (Abcam) for ROS measurements. To quantify HO-1, RBC were incubated with anti-HO-1 antibody (Abcam) and m-IgGκ BP-CFL 488 (Santa Cruz Biotechnology) as a secondary antibody. Samples were analyzed by flow cytometry. Results Our results show a 4-fold increase in ROS levels in pre/HD-RBC compared to CON-RBC. ROS levels were even further increased by 1.65-fold after HD treatment in post/HD-RBC (Figure 1). Both pre/HD-RBC and post/HD-RBC showed a similarly significant increase of 3.3-fold in HO-1 compared to CON-RBC. (Figure 1). Conclusion High levels of HO-1 may represent a defense against oxidative stress that occurs in ESKD and particularly during the HD session. Further research is needed to evaluate whether HO-1 overexpression could accelerate heme degradation and contribute to renal anemia.

scholarly journals Solute Carrier Organic Anion Transporter Family Member 3A1 Is a Bile Acid Efflux Transporter in Cholestasis

2018 ◽  
Vol 155 (5) ◽  
pp. 1578-1592.e16 ◽  
Author(s):  
Qiong Pan ◽  
Xiaoxun Zhang ◽  
Liangjun Zhang ◽  
Ying Cheng ◽  
Nan Zhao ◽  
...  
Keyword(s):  
Bile Acid ◽  
Family Member ◽  
Organic Anion ◽  
Organic Anion Transporter ◽  
Efflux Transporter ◽  
Anion Transporter ◽  
Transporter Family ◽  
Solute Carrier
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