Structure of bile acid transporter NTCP
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ABSTRACT:
SUBMITTER: Umeharu Ohto
PROVIDER: EMPIAR-11056 | biostudies-other |
REPOSITORIES: biostudies-other
Publications
Structure of the bile acid transporter and HBV receptor NTCP.
Asami Jinta J Kimura Kanako Terakado KT Fujita-Fujiharu Yoko Y Ishida Hanako H Zhang Zhikuan Z Nomura Yayoi Y Liu Kehong K Uemura Tomoko T Sato Yumi Y Ono Masatsugu M Yamamoto Masaki M Noda Takeshi T Shigematsu Hideki H Drew David D Iwata So S Shimizu Toshiyuki T Nomura Norimichi N Ohto Umeharu U
Nature 20220517 7916
Chronic infection with hepatitis B virus (HBV) affects more than 290 million people worldwide, is a major cause of cirrhosis and hepatocellular carcinoma, and results in an estimated 820,000 deaths annually<sup>1,2</sup>. For HBV infection to be established, a molecular interaction is required between the large glycoproteins of the virus envelope (known as LHBs) and the host entry receptor sodium taurocholate co-transporting polypeptide (NTCP), a sodium-dependent bile acid transporter from the b ...[more]
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Project description:Intrahepatic cholestasis of pregnancy (ICP) is estimated to impact between 0.4% and 5% of pregnancies worldwide. This disease is associated with elevated maternal bile acids and frequently untoward neonatal outcomes such as respiratory distress and asphyxia. Multiple candidate genes have been implicated, but none have provided insight into the mechanisms of neonatal respiratory distress and death. Herein our studies demonstrate that maternal cholestasis (due to Abcb11 deficiency) produces 100% neonatal death within 24h due to atelectasis producing pulmonary hypoxia, which recapitulates the respiratory distress and asphyxia of human ICP. We show that these neonates have elevated pulmonary bile acids that are associated with disrupted structure of pulmonary surfactant. Maternal absence of Nr1i2 superimposed upon Abcb11 deficiency strongly increased neonatal survival and is directly related to reduced maternal bile acid concentrations. The mechanism accounting for reduced serum bile acids in the mothers deficient in both Nr1i2 and Abcb11 appears related to disrupted reabsorption of intestinal bile acids due to changes in transporter expression. These findings provide novel insights into pulmonary failure by revealing bile acids capability to disrupt the structure of surfactant producing collapsed alveoli, pulmonary failure and ultimately death. These findings have important implications for neonatal health especially when maternal bile acids are elevated during pregnancy and highlight a potential pathway and targets amenable to therapeutic intervention to ameliorate this condition.
2015-09-23 | GSE70179 | GEO
Project description:Intrahepatic cholestasis of pregnancy (ICP) is estimated to impact between 0.4% and 5% of pregnancies worldwide. This disease is associated with elevated maternal bile acids and frequently untoward neonatal outcomes such as respiratory distress and asphyxia. Multiple candidate genes have been implicated, but none have provided insight into the mechanisms of neonatal respiratory distress and death. Herein our studies demonstrate that maternal cholestasis (due to Abcb11 deficiency) produces 100% neonatal death within 24h due to atelectasis producing pulmonary hypoxia, which recapitulates the respiratory distress and asphyxia of human ICP. We show that these neonates have elevated pulmonary bile acids that are associated with disrupted structure of pulmonary surfactant. Maternal absence of Nr1i2 superimposed upon Abcb11 deficiency strongly increased neonatal survival and is directly related to reduced maternal bile acid concentrations. The mechanism accounting for reduced serum bile acids in the mothers deficient in both Nr1i2 and Abcb11 appears related to disrupted reabsorption of intestinal bile acids due to changes in transporter expression. These findings provide novel insights into pulmonary failure by revealing bile acids capability to disrupt the structure of surfactant producing collapsed alveoli, pulmonary failure and ultimately death. These findings have important implications for neonatal health especially when maternal bile acids are elevated during pregnancy and highlight a potential pathway and targets amenable to therapeutic intervention to ameliorate this condition. We used microarrays to measure changes in gene expression profiles in lung tissues from Abcb11+/- lungs after interbreeding C57BL/6 wild-type female or C57BL/6 Abcb11-/- female mice against either C57BL/6 wild-type male mice or C57BL/6 Abcb11-/- male mice to create only heterozygote offspring. We also measured profiles in liver tissues from age-matched C57BL/6 wild-type and C57BL/6 Abcb11-/- mice. Lung tissues were collected from day E17.5, E18.5 and neonatal (N0) mice. Liver tissues were collected from 1.5-month-old C57BL/6 wildtype and Abcb11-/- mice.
2015-09-23 | E-GEOD-70179 | biostudies-arrayexpress
Project description:Intrahepatic cholestasis of pregnancy (ICP) is associated with adverse neonatal survival and is estimated to impact between 0.4 and 5% of pregnancies worldwide. Here we show that maternal cholestasis (due to Abcb11 deficiency) produces neonatal death among all offspring within 24 h of birth due to atelectasis-producing pulmonary hypoxia, which recapitulates the neonatal respiratory distress of human ICP. Neonates of Abcb11-deficient mothers have elevated pulmonary bile acids and altered pulmonary surfactant structure. Maternal absence of Nr1i2 superimposed on Abcb11 deficiency strongly reduces maternal serum bile acid concentrations and increases neonatal survival. We identify pulmonary bile acids as a key factor in the disruption of the structure of pulmonary surfactant in neonates of ICP. These findings have important implications for neonatal respiratory failure, especially when maternal bile acids are elevated during pregnancy, and highlight potential pathways and targets amenable to therapeutic intervention to ameliorate this condition.
| S-EPMC4598356 | biostudies-literature
Project description:The human apical sodium dependent bile acid transporter (hASBT) reabsorbs gram quantities of bile acid daily and is a potential prodrug target to increase oral drug absorption. In the absence of a high resolution hASBT crystal structure, 3D-QSAR modeling may prove beneficial in designing prodrug targets to hASBT. The objective was to derive a conformationally sampled pharmacophore 3D-QSAR (CSP-SAR) model for the uptake of bile acid conjugates by hASBT. A series of bile acid conjugates of glutamyl chenodeoxycholate were evaluated in terms of K(m) and normalized V(max) (normV(max)) using hASBT-MDCK cells. All monoanionic conjugates were potent substrates. Dianions, cations and zwitterions, which bound with a high affinity, were not substrates. CSP-SAR models were derived using structural and physicochemical descriptors, and evaluated via cross validation. The best CSP-SAR model for K(m) included two structural and two physiochemical descriptors, where substrate hydrophobicity enhanced affinity. A best CSP-SAR model for K(m)/normV(max) employed one structural and three physicochemical descriptors, also indicating hydrophobicity enhanced efficiency. Overall, the bile acid C-24 region accommodated a range of substituted anilines, provided a single negative charge was present near C-24. In comparing uptake findings to prior inhibition results, increased hydrophobicity enhanced activity, with dianions and zwitterions hindering activity.
| S-EPMC2997912 | biostudies-literature
Project description:The human apical sodium-dependent bile acid transporter (hASBT) may serve as a prodrug target for oral drug absorption. Synthetic, biological, NMR, and computational approaches identified the structure-activity relationships of mono- and dianionic bile acid conjugates for hASBT binding. Experimental data combined with a conformationally sampled pharmacophore/QSAR modeling approach (CSP-SAR) predicted that dianionic substituents with intramolecular hydrogen bonding between hydroxyls on the cholane skeleton and the acid group on the conjugate's aromatic ring increased conjugate hydrophobicity and improved binding affinity. Notably, the model predicted the presence of a conformational molecular switch, where shifting the carboxylate substituent on an aromatic ring by a single position controlled binding affinity. Model validation was performed by effectively shifting the spatial location of the carboxylate by inserting a methylene adjacent to the aromatic ring, resulting in the predicted alteration in binding affinity. This work illustrates conformation as a determinant of ligand physiochemical properties and ligand binding affinity to a biological transporter.
| S-EPMC2891776 | biostudies-literature
Project description:Bile acids (BAs) comprise heterogenous amphipathic cholesterol-derived molecules that carry out physicochemical and signaling functions. A major site of BA action is the terminal ileum, where enterocytes actively reuptake BAs and express high levels of BA-sensitive nuclear receptors. BA pool size and composition are affected by changes in metabolic health, and vice versa. One of several factors that differentiate BAs is the presence of a hydroxyl group on C12 of the steroid ring. 12α-Hydroxylated BAs (12HBAs) are altered in multiple disease settings, but the consequences of 12HBA abundance are incompletely understood. We employed mouse primary ileum organoids to investigate the transcriptional effects of varying 12HBA abundance in BA pools. We identified Slc30a10 as one of the top genes differentially induced by BA pools with varying 12HBA abundance. SLC30A10 is a manganese efflux transporter critical for whole-body manganese excretion. We found that BA pools, especially those low in 12HBAs, induce cellular manganese efflux and that Slc30a10 induction by BA pools is driven primarily by lithocholic acid signaling via the vitamin D receptor. Administration of lithocholic acid or a vitamin D receptor agonist resulted in increased Slc30a10 expression in mouse ileum epithelia. These data demonstrate a previously unknown role for BAs in intestinal control of manganese homeostasis.
| S-EPMC7458818 | biostudies-literature
Project description:Ileal bile acid absorption is mediated by uptake via the apical sodium-dependent bile acid transporter (ASBT), and export via the basolateral heteromeric organic solute transporter ?-? (OST?-OST?). In this study, we investigated the cytotoxic effects of enterocyte bile acid stasis in Ost?-/- mice, including the temporal relationship between intestinal injury and initiation of the enterohepatic circulation of bile acids.Ileal tissue morphometry, histology, markers of cell proliferation, gene, and protein expression were analyzed in male and female wild-type and Ost?-/- mice at postnatal days 5, 10, 15, 20, and 30. Ost?-/-Asbt-/- mice were generated and analyzed. Bile acid activation of intestinal Nrf2-activated pathways was investigated in Drosophila.As early as day 5, Ost?-/- mice showed significantly increased ileal weight per length, decreased villus height, and increased epithelial cell proliferation. This correlated with premature expression of the Asbt and induction of bile acid-activated farnesoid X receptor target genes in neonatal Ost?-/- mice. Expression of reduced nicotinamide adenine dinucleotide phosphate oxidase-1 and Nrf2-anti-oxidant responsive genes were increased significantly in neonatal Ost?-/- mice at these postnatal time points. Bile acids also activated Nrf2 in Drosophila enterocytes and enterocyte-specific knockdown of Nrf2 increased sensitivity of flies to bile acid-induced toxicity. Inactivation of the Asbt prevented the changes in ileal morphology and induction of anti-oxidant response genes in Ost?-/- mice.Early in postnatal development, loss of Ost? leads to bile acid accumulation, oxidative stress, and a restitution response in ileum. In addition to its essential role in maintaining bile acid homeostasis, Ost?-Ost? functions to protect the ileal epithelium against bile acid-induced injury. NCBI Gene Expression Omnibus: GSE99579.
| S-EPMC6009794 | biostudies-literature
Project description:Around 250 million people are infected with hepatitis B virus (HBV) worldwide1, and 15 million may also carry the satellite virus hepatitis D virus (HDV), which confers even greater risk of severe liver disease2. The HBV receptor has been identified as sodium taurocholate co-transporting polypeptide (NTCP), which interacts directly with the first 48 amino acid residues of the N-myristoylated N-terminal preS1 domain of the viral large protein3. Despite the pressing need for therapeutic agents to counter HBV, the structure of NTCP remains unsolved. This 349-residue protein is closely related to human apical sodium-dependent bile acid transporter (ASBT), another member of the solute carrier family SLC10. Crystal structures have been reported of similar bile acid transporters from bacteria4,5, and these models are believed to resemble closely both NTCP and ASBT. Here we have used cryo-electron microscopy to solve the structure of NTCP bound to an antibody, clearly showing that the transporter has no equivalent of the first transmembrane helix found in other SLC10 proteins, and that the N terminus is exposed on the extracellular face. Comparison of our structure with those of related proteins indicates a common mechanism of bile acid transport, but the NTCP structure displays an additional pocket formed by residues that are known to interact with preS1, presenting new opportunities for structure-based drug design.
| S-EPMC9242859 | biostudies-literature
Project description:Conversion of the primary bile acids cholic acid (CA) and chenodeoxycholic acid (CDCA) to the secondary bile acids deoxycholic acid (DCA) and lithocholic acid (LCA) is performed by a few species of intestinal bacteria in the genus Clostridium through a multistep biochemical pathway that removes a 7?-hydroxyl group. The rate-determining enzyme in this pathway is bile acid 7?-dehydratase (baiE). In this study, crystal structures of apo-BaiE and its putative product-bound [3-oxo-?(4,6) -lithocholyl-Coenzyme A (CoA)] complex are reported. BaiE is a trimer with a twisted ? + ? barrel fold with similarity to the Nuclear Transport Factor 2 (NTF2) superfamily. Tyr30, Asp35, and His83 form a catalytic triad that is conserved across this family. Site-directed mutagenesis of BaiE from Clostridium scindens VPI 12708 confirm that these residues are essential for catalysis and also the importance of other conserved residues, Tyr54 and Arg146, which are involved in substrate binding and affect catalytic turnover. Steady-state kinetic studies reveal that the BaiE homologs are able to turn over 3-oxo-?(4) -bile acid and CoA-conjugated 3-oxo-?(4) -bile acid substrates with comparable efficiency questioning the role of CoA-conjugation in the bile acid metabolism pathway.
| S-EPMC4755848 | biostudies-literature
Project description:Background & aimsBile acid transporters maintain bile acid homeostasis. Little is known about the functions of some transporters in cholestasis or their regulatory mechanism. We investigated the hepatic expression of solute carrier organic anion transporter family member 3A1 (SLCO3A1, also called OATP3A1) and assessed its functions during development of cholestasis.MethodsWe measured levels of OATP3A1 protein and messenger RNA and localized the protein in liver tissues from 22 patients with cholestasis and 21 patients without cholestasis, using real-time quantitative polymerase chain reaction, immunoblot, and immunofluorescence analyses. We performed experiments with Slco3a1-knockout and C57BL/6J (control) mice. Mice and Sprague-Dawley rats underwent bile duct ligation (BDL) or a sham operation. Some mice were placed on a 1% cholic acid (CA) diet to induce cholestasis or on a control diet. Serum and liver tissues were collected and analyzed; hepatic levels of bile acids and 7-α-C4 were measured using liquid chromatography/mass spectrometry. Human primary hepatocytes and hepatoma (PLC/PRF/5) cell lines were used to study mechanisms that regulate OATP3A1 expression and transport.ResultsHepatic levels of OATP3A1 messenger RNA and protein were significantly increased in liver tissues from patients with cholestasis and from rodents with BDL or 1% CA diet-induced cholestasis. Levels of fibroblast growth factor 19 (FGF19, FGF15 in rodents) were also increased in liver tissues from patients and rodents with cholestasis. FGF19 signaling activated the Sp1 transcription factor and nuclear factor κB to increase expression of OATP3A1 in hepatocytes; we found binding sites for these factors in the SLCO3A1 promoter. Slco3a1-knockout mice had shorter survival times and increased hepatic levels of bile acid, and they developed more liver injury after the 1% CA diet or BDL than control mice. In hepatoma cell lines, we found OATP3A1 to take prostaglandin E2 and thyroxine into cells and efflux bile acids.ConclusionsWe found levels of OATP3A1 to be increased in cholestatic liver tissues from patients and rodents compared with healthy liver tissues. We show that OATP3A1 functions as a bile acid efflux transporter that is up-regulated as an adaptive response to cholestasis.
| S-EPMC6221191 | biostudies-literature