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Liu N, Wang J, Wang X, Qiu S, Zhang M. Bilirubin level is decreased in patients with allergic rhinitis. J Proteomics 2023; 272:104787. [PMID: 36470582 DOI: 10.1016/j.jprot.2022.104787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/07/2022] [Accepted: 11/22/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND There are limitations in detecting methods for early diagnosis and screening of allergic rhinitis. Considering the anti-inflammatory and anti-oxidative effects of bilirubin, this study aims to explore the relationship between bilirubin and allergic rhinitis and to identify bilirubin-related candidate urinary protein biomarkers associated with allergic rhinitis. METHODS 63 allergic rhinitis patients (AR group) and 86 healthy controls (NC group) were enrolled. Venous blood was obtained to measure serum total IgE levels and bilirubin parameters. Patients in the AR group were then classified into the AR1 group (IgE > 125 IU/mL) and the AR2 group (IgE ≤ 125 IU/mL). After randomly selecting ten urine samples from the AR1 group, ten samples were chosen from the AR2 and the NC groups, respectively, according to age and gender matching. We employed a Tandem Mass Tag-Based liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) proteomics approach and targeted parallel-reaction monitoring(PRM) to identify and validate urinary biomarkers for allergic rhinitis. RESULTS Compared with the NC group, the bilirubin levels of the AR group, AR1 group, and AR2 group were significantly lower. Although the bilirubin level of the AR1 group was lower than that of the AR2 group, the difference was not significant. Further urinary proteomics analysis found that the expression levels of proteins related to bilirubin metabolism and transportation in the AR1 and AR2 groups, including ABCC1, GSTA1, GSTO1, GSTM3, GSTM5, and BLVRB, were significantly higher than those in the NC group. By PRM-based quantification, GSTA1 and GSTO1 showed significant differences in different degrees of Allergic Rhinitis groups and healthy controls. The AUC of the combined diagnosis of GSTA1 and GSTO1 was 0.79 (95% CI 0.583-0.997, P = 0.007), and the sensitivity and specificity were 100% and 60.0%, respectively. CONCLUSIONS Bilirubin levels are associated with allergic rhinitis. Our study revealed that urine proteomics has a specific value for exploring the pathophysiological mechanism of bilirubin changes in AR patients and screening possible biomarkers.
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Affiliation(s)
- Na Liu
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, China; Peking University Ninth School of Clinical Medicine, Beijing, China; Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China
| | - Jitu Wang
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, China; Peking University Ninth School of Clinical Medicine, Beijing, China; Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China
| | - Xueyan Wang
- Department of Allergy, Beijing Shijitan Hospital,Capital Medical University, Beijing, China
| | - Sainan Qiu
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, China; Peking University Ninth School of Clinical Medicine, Beijing, China; Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China
| | - Man Zhang
- Clinical Laboratory Medicine, Beijing Shijitan Hospital, Capital Medical University, Beijing, China; Peking University Ninth School of Clinical Medicine, Beijing, China; Beijing Key Laboratory of Urinary Cellular Molecular Diagnostics, Beijing, China.
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Bile Duct Ligation Impairs Function and Expression of Mrp1 at Rat Blood–Retinal Barrier via Bilirubin-Induced P38 MAPK Pathway Activations. Int J Mol Sci 2022; 23:ijms23147666. [PMID: 35887010 PMCID: PMC9318728 DOI: 10.3390/ijms23147666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 07/04/2022] [Accepted: 07/07/2022] [Indexed: 11/29/2022] Open
Abstract
Liver injury is often associated with hepatic retinopathy, resulting from accumulation of retinal toxins due to blood–retinal barrier (BRB) dysfunction. Retinal pigment epithelium highly expresses MRP1/Mrp1. We aimed to investigate whether liver injury affects the function and expression of retinal Mrp1 using bile duct ligation (BDL) rats. Retinal distributions of fluorescein and 2,4-dinitrophenyl-S-glutathione were used for assessing Mrp1 function. BDL significantly increased distributions of the two substrates and bilirubin, downregulated Mrp1 protein, and upregulated phosphorylation of p38 and MK2 in the retina. BDL neither affected the retinal distribution of FITC-dextran nor expressions of ZO-1 and claudin-5, demonstrating intact BRB integrity. In ARPE-19 cells, BDL rat serum or bilirubin decreased MRP1 expression and enhanced p38 and MK2 phosphorylation. Both inhibiting and silencing p38 significantly reversed the bilirubin- and anisomycin-induced decreases in MRP1 protein. Apparent permeability coefficients of fluorescein in the A-to-B direction (Papp, A-to-B) across the ARPE-19 monolayer were greater than Papp, B-to-A. MK571 or bilirubin significantly decreased Papp, A-to-B of fluorescein. Bilirubin treatment significantly downregulated Mrp1 function and expression without affecting integrity of BRB and increased bilirubin levels and phosphorylation of p38 and MK2 in rat retina. In conclusion, BDL downregulates the expression and function of retina Mrp1 by activating the p38 MAPK pathway due to increased bilirubin levels.
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Hanssen KM, Haber M, Fletcher JI. Targeting multidrug resistance-associated protein 1 (MRP1)-expressing cancers: Beyond pharmacological inhibition. Drug Resist Updat 2021; 59:100795. [PMID: 34983733 DOI: 10.1016/j.drup.2021.100795] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/30/2021] [Accepted: 09/05/2021] [Indexed: 12/30/2022]
Abstract
Resistance to chemotherapy remains one of the most significant obstacles to successful cancer treatment. While inhibiting drug efflux mediated by ATP-binding cassette (ABC) transporters is a seemingly attractive and logical approach to combat multidrug resistance (MDR), small molecule inhibition of ABC transporters has so far failed to confer clinical benefit, despite considerable efforts by medicinal chemists, biologists, and clinicians. The long-sought treatment to eradicate cancers displaying ABC transporter overexpression may therefore lie within alternative targeting strategies. When aberrantly expressed, the ABC transporter multidrug resistance-associated protein 1 (MRP1, ABCC1) confers MDR, but can also shift cellular redox balance, leaving the cell vulnerable to select agents. Here, we explore the physiological roles of MRP1, the rational for targeting this transporter in cancer, the development of small molecule MRP1 inhibitors, and the most recent developments in alternative therapeutic approaches for targeting cancers with MRP1 overexpression. We discuss approaches that extend beyond simple MRP1 inhibition by exploiting the collateral sensitivity to glutathione depletion and ferroptosis, the rationale for targeting the shared transcriptional regulators of both MRP1 and glutathione biosynthesis, advances in gene silencing, and new molecules that modulate transporter activity to the detriment of the cancer cell. These strategies illustrate promising new approaches to address multidrug resistant disease that extend beyond the simple reversal of MDR and offer exciting routes for further research.
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Affiliation(s)
- Kimberley M Hanssen
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Sydney, Sydney, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia
| | - Michelle Haber
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Sydney, Sydney, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia
| | - Jamie I Fletcher
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Sydney, Sydney, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia.
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Ree IMC, van 't Oever RM, Zwiers C, Verweij EJT, Oepkes D, de Haas M, Lopriore E. Are fetal bilirubin levels associated with the need for neonatal exchange transfusions in hemolytic disease of the fetus and newborn? Am J Obstet Gynecol MFM 2021; 3:100332. [PMID: 33609759 DOI: 10.1016/j.ajogmf.2021.100332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 02/12/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Fetal bilirubin is routinely measured at our center when taking a pretransfusion blood sample at intrauterine transfusions in hemolytic disease of the fetus and newborn. However, the clinical value of fetal bilirubin assessment is not well known, and the information is rarely used. We speculated that there could be a role for this measurement in predicting the need for neonatal exchange transfusion. OBJECTIVE This study aimed to evaluate the predictive value of fetal bilirubin for exchange transfusions in severe hemolytic disease of the fetus and newborn. STUDY DESIGN A total of 186 infants with Rh alloantibody-mediated hemolytic disease of the fetus and newborn treated with one or more intrauterine transfusions at the Leiden University Medical Center between January 2006 and June 2020 were included in this observational study. Antenatal and postnatal factors were compared between infants with and without exchange transfusion treatments. The primary outcome was the fetal bilirubin levels before the last intrauterine transfusion in relation to the need for exchange transfusion. RESULTS In a multivariate logistic regression analysis, the fetal bilirubin level before the last intrauterine transfusions (odds ratio, 1.32; 95% confidence interval, 1.09-1.61 per 1 mg/dL) and the total number of intrauterine transfusions (odds ratio, 0.63; 95% confidence interval, 0.44-0.91 per intrauterine transfusion) were independently associated with the need for exchange transfusion. The area under the curve was determined at 0.71. A Youden index was calculated at 0.43. The corresponding fetal bilirubin level was 5 mg/dL and had a sensitivity of 79% and a specificity of 64%. CONCLUSION A high fetal bilirubin level before the last intrauterine transfusion was associated with a high likelihood of neonatal exchange transfusion.
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Affiliation(s)
- Isabelle M C Ree
- Center for Clinical Transfusion Research, Sanquin Research, Leiden, the Netherlands (Drs Ree and Haas); Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands (Dr Ree, Ms Oever, and Dr Lopriore).
| | - Renske M van 't Oever
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands (Dr Ree, Ms Oever, and Dr Lopriore)
| | - Carolien Zwiers
- Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, the Netherlands (Drs Zwiers, Verweij, and Oepkes)
| | - E J T Verweij
- Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, the Netherlands (Drs Zwiers, Verweij, and Oepkes)
| | - Dick Oepkes
- Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Center, Leiden, the Netherlands (Drs Zwiers, Verweij, and Oepkes)
| | - Masja de Haas
- Center for Clinical Transfusion Research, Sanquin Research, Leiden, the Netherlands (Drs Ree and Haas); Department of Immunohematology and Blood Transfusion, Leiden University Medical Center, Leiden, the Netherlands (Dr Haas); Department of Immunohematology Diagnostics, Sanquin, Amsterdam, the Netherlands (Dr Haas)
| | - Enrico Lopriore
- Division of Neonatology, Department of Pediatrics, Leiden University Medical Center, Leiden, the Netherlands (Dr Ree, Ms Oever, and Dr Lopriore)
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Bianco A, Dvořák A, Capková N, Gironde C, Tiribelli C, Furger C, Vitek L, Bellarosa C. The Extent of Intracellular Accumulation of Bilirubin Determines Its Anti- or Pro-Oxidant Effect. Int J Mol Sci 2020; 21:ijms21218101. [PMID: 33143041 PMCID: PMC7663266 DOI: 10.3390/ijms21218101] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 10/26/2020] [Accepted: 10/28/2020] [Indexed: 12/14/2022] Open
Abstract
Background: Severe hyperbilirubinemia can cause permanent neurological damage in particular in neonates, whereas mildly elevated serum bilirubin protects from various oxidative stress-mediated diseases. The present work aimed to establish the intracellular unconjugated bilirubin concentrations (iUCB) thresholds differentiating between anti- and pro-oxidant effects. Methods: Hepatic (HepG2), heart endothelial (H5V), kidney tubular (HK2) and neuronal (SH-SY5Y) cell lines were exposed to increasing concentration of bilirubin. iUCB, cytotoxicity, intracellular reactive oxygen species (ROS) concentrations, and antioxidant capacity (50% efficacy concentration (EC50)) were determined. Results: Exposure of SH-SY5Y to UCB concentration > 3.6 µM (iUCB of 25 ng/mg) and >15 µM in H5V and HK2 cells (iUCB of 40 ng/mg) increased intracellular ROS production (p < 0.05). EC50 of the antioxidant activity was 21 µM (iUCB between 5.4 and 21 ng/mg) in HepG2 cells, 0.68 µM (iUCB between 3.3 and 7.5 ng/mg) in SH-SY5Y cells, 2.4 µM (iUCB between 3 and 6.7 ng/mg) in HK2 cells, and 4 µM (iUCB between 4.7 and 7.5 ng/mg) in H5V cells. Conclusions: In all the cell lines studied, iUCB of around 7 ng/mg protein had antioxidant activities, while iUCB > 25 ng/mg protein resulted in a prooxidant and cytotoxic effects. UCB metabolism was found to be cell-specific resulting in different iUCB.
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Affiliation(s)
- Annalisa Bianco
- Italian Liver Foundation (FIF), Bldg Q—AREA Science Park Basovizza, SS14 Km 163,5, 34149 Trieste, Italy; (A.B.); (C.T.)
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
| | - Aleš Dvořák
- Institute of Medical Biochemistry and Laboratory Diagnostics, Faculty General Hospital and 1st Faculty of Medicine, Charles University, 121 08 Prague 2, Czech Republic; (A.D.); (N.C.); (L.V.)
| | - Nikola Capková
- Institute of Medical Biochemistry and Laboratory Diagnostics, Faculty General Hospital and 1st Faculty of Medicine, Charles University, 121 08 Prague 2, Czech Republic; (A.D.); (N.C.); (L.V.)
| | - Camille Gironde
- AOP/MH2F Team, LAAS-CNRS, 7 avenue de l’Europe, 31400 Toulouse, France; (C.G.); (C.F.)
| | - Claudio Tiribelli
- Italian Liver Foundation (FIF), Bldg Q—AREA Science Park Basovizza, SS14 Km 163,5, 34149 Trieste, Italy; (A.B.); (C.T.)
| | - Christophe Furger
- AOP/MH2F Team, LAAS-CNRS, 7 avenue de l’Europe, 31400 Toulouse, France; (C.G.); (C.F.)
| | - Libor Vitek
- Institute of Medical Biochemistry and Laboratory Diagnostics, Faculty General Hospital and 1st Faculty of Medicine, Charles University, 121 08 Prague 2, Czech Republic; (A.D.); (N.C.); (L.V.)
- 4 Department of Internal Medicine, Faculty General Hospital and 1 Faculty of Medicine, Charles University, 121 08 Prague 2, Czech Republic
| | - Cristina Bellarosa
- Italian Liver Foundation (FIF), Bldg Q—AREA Science Park Basovizza, SS14 Km 163,5, 34149 Trieste, Italy; (A.B.); (C.T.)
- Correspondence:
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Hansen TWR, Wong RJ, Stevenson DK. Molecular Physiology and Pathophysiology of Bilirubin Handling by the Blood, Liver, Intestine, and Brain in the Newborn. Physiol Rev 2020; 100:1291-1346. [PMID: 32401177 DOI: 10.1152/physrev.00004.2019] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Bilirubin is the end product of heme catabolism formed during a process that involves oxidation-reduction reactions and conserves iron body stores. Unconjugated hyperbilirubinemia is common in newborn infants, but rare later in life. The basic physiology of bilirubin metabolism, such as production, transport, and excretion, has been well described. However, in the neonate, numerous variables related to nutrition, ethnicity, and genetic variants at several metabolic steps may be superimposed on the normal physiological hyperbilirubinemia that occurs in the first week of life and results in bilirubin levels that may be toxic to the brain. Bilirubin exists in several isomeric forms that differ in their polarities and is considered a physiologically important antioxidant. Here we review the chemistry of the bilirubin molecule and its metabolism in the body with a particular focus on the processes that impact the newborn infant, and how differences relative to older children and adults contribute to the risk of developing both acute and long-term neurological sequelae in the newborn infant. The final section deals with the interplay between the brain and bilirubin and its entry, clearance, and accumulation. We conclude with a discussion of the current state of knowledge regarding the mechanism(s) of bilirubin neurotoxicity.
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Affiliation(s)
- Thor W R Hansen
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - Ronald J Wong
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
| | - David K Stevenson
- Division of Paediatric and Adolescent Medicine, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway; and Department of Pediatrics, Stanford University School of Medicine, Stanford, California
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Tátrai P, Krajcsi P. Prediction of Drug-Induced Hyperbilirubinemia by In Vitro Testing. Pharmaceutics 2020; 12:pharmaceutics12080755. [PMID: 32796590 PMCID: PMC7465333 DOI: 10.3390/pharmaceutics12080755] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/28/2020] [Accepted: 08/07/2020] [Indexed: 12/23/2022] Open
Abstract
Bilirubin, the end product of heme catabolism, is produced continuously in the body and may reach toxic levels if accumulates in the serum and tissues; therefore, a highly efficient mechanism evolved for its disposition. Normally, unconjugated bilirubin enters hepatocytes through the uptake transporters organic anion transporting polypeptide (OATP) 1B1 and 1B3, undergoes glucuronidation by the Phase II enzyme UDP glucuronosyltransferase 1A1 (UGT1A1), and conjugated forms are excreted into the bile by the canalicular export pump multidrug resistance protein 2 (MRP2). Any remaining conjugated bilirubin is transported back to the blood by MRP3 and passed on for uptake and excretion by downstream hepatocytes or the kidney. The bile salt export pump BSEP as the main motor of bile flow is indirectly involved in bilirubin disposition. Genetic mutations and xenobiotics that interfere with this machinery may impede bilirubin disposition and cause hyperbilirubinemia. Several pharmaceutical compounds are known to cause hyperbilirubinemia via inhibition of OATP1Bs, UGT1A1, or BSEP. Herein we briefly review the in vitro prediction methods that serve to identify drugs with a potential to induce hyperbilirubinemia. In vitro assays can be deployed early in drug development and may help to minimize late-stage attrition. Based on current evidence, drugs that behave as mono- or multispecific inhibitors of OATP1B1, UGT1A1, and BSEP in vitro are at risk of causing clinically significant hyperbilirubinemia. By integrating inhibition data from in vitro assays, drug serum concentrations, and clinical reports of hyperbilirubinemia, predictor cut-off values have been established and are provisionally suggested in this review. Further validation of in vitro readouts to clinical outcomes is expected to enhance the predictive power of these assays.
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Affiliation(s)
- Péter Tátrai
- Solvo Biotechnology, Science Park, Building B1, 4-20 Irinyi József utca, H-1117 Budapest, Hungary;
| | - Péter Krajcsi
- Solvo Biotechnology, Science Park, Building B1, 4-20 Irinyi József utca, H-1117 Budapest, Hungary;
- Faculty of Health Sciences, Semmelweis University, H-1085 Budapest, Hungary
- Faculty of Information Technology and Bionics, Péter Pázmány Catholic University, H-1083 Budapest, Hungary
- Correspondence:
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Experimental models assessing bilirubin neurotoxicity. Pediatr Res 2020; 87:17-25. [PMID: 31493769 DOI: 10.1038/s41390-019-0570-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/29/2019] [Accepted: 08/16/2019] [Indexed: 02/08/2023]
Abstract
The molecular and cellular events leading to bilirubin-induced neurotoxicity, the mechanisms regulating liver and intestine expression in neonates, and alternative pathways of bilirubin catabolism remain incompletely defined. To answer these questions, researchers have developed a number of model systems to closely recapitulate the main characteristics of the disease, ranging from tissue cultures to engineered mouse models. In the present review we describe in vitro, ex vivo, and in vivo models developed to study bilirubin metabolism and neurotoxicity, with a special focus on the use of engineered animal models. In addition, we discussed the most recent studies related to potential therapeutic approaches to treat neonatal hyperbilirubinemia, ranging from anti-inflammatory drugs, activation of nuclear receptor pathways, blockade of bilirubin catabolism, and stimulation of alternative bilirubin-disposal pathways.
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9
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Le Pichon JB, Riordan SM, Shapiro SM. Hyperbilirubinemia and the Risk for Brain Injury. Neurology 2019. [DOI: 10.1016/b978-0-323-54392-7.00010-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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10
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Bortolussi G, Muro AF. Advances in understanding disease mechanisms and potential treatments for Crigler–Najjar syndrome. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1495558] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Giulia Bortolussi
- Mouse Molecular Genetics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Andrés Fernando Muro
- Mouse Molecular Genetics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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11
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Čvorović J, Passamonti S. Membrane Transporters for Bilirubin and Its Conjugates: A Systematic Review. Front Pharmacol 2017; 8:887. [PMID: 29259555 PMCID: PMC5723324 DOI: 10.3389/fphar.2017.00887] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Accepted: 11/17/2017] [Indexed: 12/16/2022] Open
Abstract
Background: Bilirubin is a highly-hydrophobic tetrapyrrole which binds to plasma albumin. It is conjugated in the liver to glucuronic acid, and the water-soluble glucuronides are excreted in urine and bile. The membrane transporters of bilirubin diglucuronide are well-known. Still undefined are however the transporters performing the uptake of bilirubin from the blood into the liver, a process known to be fast and not rate-limited. The biological importance of this process may be appraised by considering that in normal adults 200–300 mg of bilirubin are produced daily, as a result of the physiologic turnover of hemoglobin and cellular cytochromes. Nevertheless, research in this field has yielded controversial and contradicting results. We have undertaken a systematic review of the literature, believing in its utility to improve the existing knowledge and promote further advancements. Methods: We have sourced the PubMed database until 30 June 2017 by applying 5 sequential searches. Screening and eligibility criteria were applied to retain research articles reporting results obtained by using bilirubin molecules in membrane transport assays in vitro or by assessing serum bilirubin levels in in vivo experiments. Results: We have identified 311 articles, retaining 44, reporting data on experimental models having 6 incremental increases of complexity (isolated proteins, membrane vesicles, cells, organ fragments, in vivo rodents, and human studies), demonstrating the function of 19 membrane transporters, encoded by either SLCO or ABC genes. Three other bilirubin transporters have no gene, though one, i.e., bilitranslocase, is annotated in the Transporter Classification Database. Conclusions: This is the first review that has systematically examined the membrane transporters for bilirubin and its conjugates. Paradoxically, the remarkable advancements in the field of membrane transport of bilirubin have pointed to the elusive mechanism(s) enabling bilirubin to diffuse into the liver as if no cellular boundary existed.
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Affiliation(s)
- Jovana Čvorović
- Department of Life Sciences, University of Trieste, Trieste, Italy
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12
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Bockor L, Bortolussi G, Vodret S, Iaconcig A, Jašprová J, Zelenka J, Vitek L, Tiribelli C, Muro AF. Modulation of bilirubin neurotoxicity by the Abcb1 transporter in the Ugt1-/- lethal mouse model of neonatal hyperbilirubinemia. Hum Mol Genet 2017; 26:145-157. [PMID: 28025333 DOI: 10.1093/hmg/ddw375] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 10/27/2016] [Indexed: 01/20/2023] Open
Abstract
Moderate neonatal jaundice is the most common clinical condition during newborn life. However, a combination of factors may result in acute hyperbilirubinemia, placing infants at risk of developing bilirubin encephalopathy and death by kernicterus. While most risk factors are known, the mechanisms acting to reduce susceptibility to bilirubin neurotoxicity remain unclear. The presence of modifier genes modulating the risk of developing bilirubin-induced brain damage is increasingly being recognised. The Abcb1 and Abcc1 members of the ABC family of transporters have been suggested to have an active role in exporting unconjugated bilirubin from the central nervous system into plasma. However, their role in reducing the risk of developing neurological damage and death during neonatal development is still unknown.To this end, we mated Abcb1a/b-/- and Abcc1-/- strains with Ugt1-/- mice, which develop severe neonatal hyperbilirubinemia. While about 60% of Ugt1-/- mice survived after temporary phototherapy, all Abcb1a/b-/-/Ugt1-/- mice died before postnatal day 21, showing higher cerebellar levels of unconjugated bilirubin. Interestingly, Abcc1 role appeared to be less important.In the cerebellum of Ugt1-/- mice, hyperbilirubinemia induced the expression of Car and Pxr nuclear receptors, known regulators of genes involved in the genotoxic response.We demonstrated a critical role of Abcb1 in protecting the cerebellum from bilirubin toxicity during neonatal development, the most clinically relevant phase for human babies, providing further understanding of the mechanisms regulating bilirubin neurotoxicity in vivo. Pharmacological treatments aimed to increase Abcb1 and Abcc1 expression, could represent a therapeutic option to reduce the risk of bilirubin neurotoxicity.
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Affiliation(s)
- Luka Bockor
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Giulia Bortolussi
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Simone Vodret
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Alessandra Iaconcig
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
| | - Jana Jašprová
- Institute of Medical Biochemistry and Laboratory Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Jaroslav Zelenka
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Technicka 3, 166 28 Prague, Czech Republic
| | - Libor Vitek
- Institute of Medical Biochemistry and Laboratory Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic.,Fourth Department of Internal Medicine, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Claudio Tiribelli
- Centro Studi Fegato, Fondazione Italiana Fegato, AREA Science Park, Campus Basovizza Trieste, Italy and
| | - Andrés F Muro
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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Joshi AA, Vaidya SS, St-Pierre MV, Mikheev AM, Desino KE, Nyandege AN, Audus KL, Unadkat JD, Gerk PM. Placental ABC Transporters: Biological Impact and Pharmaceutical Significance. Pharm Res 2016; 33:2847-2878. [PMID: 27644937 DOI: 10.1007/s11095-016-2028-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/23/2016] [Indexed: 01/02/2023]
Abstract
The human placenta fulfills a variety of essential functions during prenatal life. Several ABC transporters are expressed in the human placenta, where they play a role in the transport of endogenous compounds and may protect the fetus from exogenous compounds such as therapeutic agents, drugs of abuse, and other xenobiotics. To date, considerable progress has been made toward understanding ABC transporters in the placenta. Recent studies on the expression and functional activities are discussed. This review discusses the placental expression and functional roles of several members of ABC transporter subfamilies B, C, and G including MDR1/P-glycoprotein, the MRPs, and BCRP, respectively. Since placental ABC transporters modulate fetal exposure to various compounds, an understanding of their functional and regulatory mechanisms will lead to more optimal medication use when necessary in pregnancy.
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Affiliation(s)
- Anand A Joshi
- Department of Pharmaceutics, Virginia Commonwealth University School of Pharmacy, Richmond, Virginia, 23298-0533, USA
| | - Soniya S Vaidya
- Department of Pharmaceutics, Virginia Commonwealth University School of Pharmacy, Richmond, Virginia, 23298-0533, USA
- Novartis Institutes of Biomedical Research, Cambridge, Massachusetts, USA
| | - Marie V St-Pierre
- Department of Clinical Pharmacology and Toxicology, University of Zurich Hospital, Zurich, Switzerland
| | - Andrei M Mikheev
- Department of Pharmaceutics, University of Washington School of Pharmacy, Seattle, Washington, USA
- Department of Neurosurgery, Institute of Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, Washington, 98109, USA
| | - Kelly E Desino
- Department of Pharmaceutical Chemistry, University of Kansas School of Pharmacy, Lawrence, Kansas, USA
- Abbvie Inc, North Chicago, Illinois, USA
| | - Abner N Nyandege
- Department of Pharmaceutics, Virginia Commonwealth University School of Pharmacy, Richmond, Virginia, 23298-0533, USA
| | - Kenneth L Audus
- Department of Pharmaceutical Chemistry, University of Kansas School of Pharmacy, Lawrence, Kansas, USA
| | - Jashvant D Unadkat
- Department of Pharmaceutics, University of Washington School of Pharmacy, Seattle, Washington, USA
| | - Phillip M Gerk
- Department of Pharmaceutics, Virginia Commonwealth University School of Pharmacy, Richmond, Virginia, 23298-0533, USA.
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14
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Abstract
Although phototherapy was introduced as early as 1950’s, the potential biological effects of bilirubin photoisomers (PI) generated during phototherapy remain unclear. The aim of our study was to isolate bilirubin PI in their pure forms and to assess their biological effects in vitro. The three major bilirubin PI (ZE- and EZ-bilirubin and Z-lumirubin) were prepared by photo-irradiation of unconjugated bilirubin. The individual photoproducts were chromatographically separated (TLC, HPLC), and their identities verified by mass spectrometry. The role of Z-lumirubin (the principle bilirubin PI) on the dissociation of bilirubin from albumin was tested by several methods: peroxidase, fluorescence quenching, and circular dichroism. The biological effects of major bilirubin PI (cell viability, expression of selected genes, cell cycle progression) were tested on the SH-SY5Y human neuroblastoma cell line. Lumirubin was found to have a binding site on human serum albumin, in the subdomain IB (or at a close distance to it); and thus, different from that of bilirubin. Its binding constant to albumin was much lower when compared with bilirubin, and lumirubin did not affect the level of unbound bilirubin (Bf). Compared to unconjugated bilirubin, bilirubin PI did not have any effect on either SH-SY5Y cell viability, the expression of genes involved in bilirubin metabolism or cell cycle progression, nor in modulation of the cell cycle phase. The principle bilirubin PI do not interfere with bilirubin albumin binding, and do not exert any toxic effect on human neuroblastoma cells.
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15
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Cross-talk between neurons and astrocytes in response to bilirubin: adverse secondary impacts. Neurotox Res 2015; 26:1-15. [PMID: 24122290 DOI: 10.1007/s12640-013-9427-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Revised: 09/23/2013] [Accepted: 09/24/2013] [Indexed: 12/25/2022]
Abstract
Previous studies using monotypic nerve cell cultures have shown that bilirubin-induced neurological dysfunction (BIND) involves apoptosis and necrosis-like cell death, following neuritic atrophy and astrocyte activation,and that glycoursodeoxycholic acid (GUDCA) has therapeutic efficacy against BIND. Cross-talk between neurons and astrocytes may protect or aggravate neurotoxicity by unconjugated bilirubin (UCB). In a previous work we have shown that bidirectional signaling during astrocyte-neuron recognition attenuates neuronal damage by UCB. Here, we investigated whether the establishment of neuron-astrocyte homeostasis prior to cell exposure to UCB was instead associated with a lower resistance of neurons to UCB toxicity, and if the pro-survival properties of GUDCA were replicated in that experimental model. We have introduced a 24 h adaptation period for neuron-glia communication prior to the 48 h treatment with UCB. In such conditions, UCB induced glial activation, which aggravated neuronal damage, comprising increased apoptosis,cell demise and neuritic atrophy, which were completely prevented in the presence of GUDCA. Neuronal multidrug resistance-associated protein 1 expression and tumor necrosis factor-a secretion, although unchanged by UCB, increased in the presence of astrocytes. The rise in S100B and nitric oxide in the co-cultures medium may have contributed to UCB neurotoxicity. Since the levels of these diffusible molecules did not change by GUDCA we may assume that they are not directly involved in its beneficial effects. Data indicate that astrocytes, in an indirect neuron-astrocyte co-culture model and after homeostatic setting regulation of the system, are critically influencing neurodegeneration by UCB, and support GUDCA for the prevention of BIND.
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16
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Bortolussi G, Zentillin L, Vaníkova J, Bockor L, Bellarosa C, Mancarella A, Vianello E, Tiribelli C, Giacca M, Vitek L, Muro AF. Life-long correction of hyperbilirubinemia with a neonatal liver-specific AAV-mediated gene transfer in a lethal mouse model of Crigler-Najjar Syndrome. Hum Gene Ther 2014; 25:844-55. [PMID: 25072305 PMCID: PMC4175423 DOI: 10.1089/hum.2013.233] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 07/21/2014] [Indexed: 12/21/2022] Open
Abstract
Null mutations in the UGT1A1 gene result in Crigler-Najjar syndrome type I (CNSI), characterized by severe hyperbilirubinemia and constant risk of developing neurological damage. Phototherapy treatment lowers plasma bilirubin levels, but its efficacy is limited and liver transplantation is required. To find alternative therapies, we applied AAV liver-specific gene therapy to a lethal mouse model of CNSI. We demonstrated that a single neonatal hUGT1A1 gene transfer was successful and the therapeutic effect lasted up to 17 months postinjection. The therapeutic effect was mediated by the presence of transcriptionally active double-stranded episomes. We also compared the efficacy of two different gene therapy approaches: liver versus skeletal muscle transgene expression. We observed that 5-8% of normal liver expression and activity levels were sufficient to significantly reduce bilirubin levels and maintain lifelong low plasma bilirubin concentration (3.1±1.5 mg/dl). In contrast, skeletal muscle was not able to efficiently lower bilirubin (6.4±2.0 mg/dl), despite 20-30% of hUgt1a1 expression levels, compared with normal liver. We propose that this remarkable difference in gene therapy efficacy could be related to the absence of the Mrp2 and Mrp3 transporters of conjugated bilirubin in muscle. Taken together, our data support the concept that liver is the best organ for efficient and long-term CNSI gene therapy, and suggest that the use of extra-hepatic tissues should be coupled to the presence of bilirubin transporters.
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Affiliation(s)
- Giulia Bortolussi
- International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
| | - Lorena Zentillin
- International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
| | - Jana Vaníkova
- Institute of Medical Biochemistry and Laboratory Medicine, First Faculty of Medicine, Charles University, 120 00 Prague, Czech Republic
| | - Luka Bockor
- International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
| | - Cristina Bellarosa
- Centro Studi Fegato, Fondazione Italiana Fegato, AREA Science Park, Campus Basovizza, 34149 Trieste, Italy
| | - Antonio Mancarella
- Centro Studi Fegato, Fondazione Italiana Fegato, AREA Science Park, Campus Basovizza, 34149 Trieste, Italy
| | - Eleonora Vianello
- Centro Studi Fegato, Fondazione Italiana Fegato, AREA Science Park, Campus Basovizza, 34149 Trieste, Italy
| | - Claudio Tiribelli
- Centro Studi Fegato, Fondazione Italiana Fegato, AREA Science Park, Campus Basovizza, 34149 Trieste, Italy
- Department of Medical Science, University of Trieste, 34128 Trieste, Italy
| | - Mauro Giacca
- International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
| | - Libor Vitek
- Institute of Medical Biochemistry and Laboratory Medicine, First Faculty of Medicine, Charles University, 120 00 Prague, Czech Republic
- Fourth Department of Internal Medicine, First Faculty of Medicine, Charles University, 120 00 Prague, Czech Republic
| | - Andrés F. Muro
- International Centre for Genetic Engineering and Biotechnology, 34149 Trieste, Italy
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17
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Cross-Talk Between Neurons and Astrocytes in Response to Bilirubin: Early Beneficial Effects. Neurochem Res 2013; 38:644-59. [DOI: 10.1007/s11064-012-0963-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 12/17/2012] [Accepted: 12/21/2012] [Indexed: 12/31/2022]
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18
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Inhibition of the MRP1-mediated transport of the menadione-glutathione conjugate (thiodione) in HeLa cells as studied by SECM. Proc Natl Acad Sci U S A 2012; 109:11522-7. [PMID: 22679290 DOI: 10.1073/pnas.1201555109] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Oxidative stress induced in live HeLa cells by menadione (2-methyl-1,4-napthaquinone) was studied in real time by scanning electrochemical microscopy (SECM). The hydrophobic molecule menadione diffuses through a living cell membrane where it is toxic to the cell. However, in the cell it is conjugated with glutathione to form thiodione. Thiodione is then recognized and transported across the cell membrane via the ATP-driven MRP1 pump. In the extracellular environment, thiodione was detected by the SECM tip at levels of 140, 70, and 35 µM upon exposure of the cells to menadione concentrations of 500, 250, and 125 µM, respectively. With the aid of finite element modeling, the kinetics of thiodione transport was determined to be 1.6 10(-7) m/s, about 10 times faster than menadione uptake. Selective inhibition of these MRP1 pumps inside live HeLa cells by MK571 produced a lower thiodione concentration of 50 µM in presence of 500 µM menadione and 50 µM MK571. A similar reduced (50% drop) thiodione efflux was observed in the presence of monoclonal antibody QCRL-4, a selective blocking agent of the MRP1 pumps. The reduced thiodione flux confirmed that thiodione was transported by MRP1, and that glutathione is an essential substrate for MRP1-mediated transport. This finding demonstrates the usefulness of SECM in quantitative studies of MRP1 inhibitors and suggests that monoclonal antibodies can be a useful tool in inhibiting the transport of these MDR pumps, and thereby aiding in overcoming multidrug resistance.
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19
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Brites D. The evolving landscape of neurotoxicity by unconjugated bilirubin: role of glial cells and inflammation. Front Pharmacol 2012; 3:88. [PMID: 22661946 PMCID: PMC3361682 DOI: 10.3389/fphar.2012.00088] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 04/23/2012] [Indexed: 12/13/2022] Open
Abstract
Unconjugated hyperbilirubinemia is a common condition in the first week of postnatal life. Although generally harmless, some neonates may develop very high levels of unconjugated bilirubin (UCB), which may surpass the protective mechanisms of the brain in preventing UCB accumulation. In this case, both short-term and long-term neurodevelopmental disabilities, such as acute and chronic UCB encephalopathy, known as kernicterus, or more subtle alterations defined as bilirubin-induced neurological dysfunction (BIND) may be produced. There is a tremendous variability in babies' vulnerability toward UCB for reasons not yet explained, but preterm birth, sepsis, hypoxia, and hemolytic disease are comprised as risk factors. Therefore, UCB levels and neurological abnormalities are not strictly correlated. Even nowadays, the mechanisms of UCB neurotoxicity are still unclear, as are specific biomarkers, and little is known about lasting sequelae attributable to hyperbilirubinemia. On autopsy, UCB was shown to be within neurons, neuronal processes, and microglia, and to produce loss of neurons, demyelination, and gliosis. In isolated cell cultures, UCB was shown to impair neuronal arborization and to induce the release of pro-inflammatory cytokines from microglia and astrocytes. However, cell dependent sensitivity to UCB toxicity and the role of each nerve cell type remains not fully understood. This review provides a comprehensive insight into cell susceptibilities and molecular targets of UCB in neurons, astrocytes, and oligodendrocytes, and on phenotypic and functional responses of microglia to UCB. Interplay among glia elements and cross-talk with neurons, with a special emphasis in the UCB-induced immunostimulation, and the role of sepsis in BIND pathogenesis are highlighted. New and interesting data on the anti-inflammatory and antioxidant activities of different pharmacological agents are also presented, as novel and promising additional therapeutic approaches to BIND.
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Affiliation(s)
- Dora Brites
- Neuron Glia Biology in Health and Disease Unit, Research Institute for Medicines and Pharmaceutical Sciences, Faculty of Pharmacy, University of Lisbon Lisbon, Portugal
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20
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Gazzin S, Strazielle N, Tiribelli C, Ghersi-Egea JF. Transport and metabolism at blood-brain interfaces and in neural cells: relevance to bilirubin-induced encephalopathy. Front Pharmacol 2012; 3:89. [PMID: 22629246 PMCID: PMC3355510 DOI: 10.3389/fphar.2012.00089] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/25/2012] [Indexed: 01/16/2023] Open
Abstract
Bilirubin, the end-product of heme catabolism, circulates in non-pathological plasma mostly as a protein-bound species. When bilirubin concentration builds up, the free fraction of the molecule increases. Unbound bilirubin then diffuses across blood-brain interfaces (BBIs) into the brain, where it accumulates and exerts neurotoxic effects. In this classical view of bilirubin neurotoxicity, BBIs act merely as structural barriers impeding the penetration of the pigment-bound carrier protein, and neural cells are considered as passive targets of its toxicity. Yet, the role of BBIs in the occurrence of bilirubin encephalopathy appears more complex than being simple barriers to the diffusion of bilirubin, and neural cells such as astrocytes and neurons can play an active role in controlling the balance between the neuroprotective and neurotoxic effects of bilirubin. This article reviews the emerging in vivo and in vitro data showing that transport and metabolic detoxification mechanisms at the blood-brain and blood-cerebrospinal fluid barriers may modulate bilirubin flux across both cellular interfaces, and that these protective functions can be affected in chronic unconjugated hyperbilirubinemia. Then the in vivo and in vitro arguments in favor of the physiological antioxidant function of intracerebral bilirubin are presented, as well as the potential role of transporters such as ABCC1 and metabolizing enzymes such as cytochromes P-450 in setting the cerebral cell- and structure-specific toxicity of bilirubin following hyperbilirubinemia. The relevance of these data to the pathophysiology of bilirubin-induced neurological diseases is discussed.
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Affiliation(s)
- Silvia Gazzin
- Italian Liver Foundation, AREA Science Park Basovizza Trieste, Italy
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21
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Gazzin S, Berengeno AL, Strazielle N, Fazzari F, Raseni A, Ostrow JD, Wennberg R, Ghersi-Egea JF, Tiribelli C. Modulation of Mrp1 (ABCc1) and Pgp (ABCb1) by bilirubin at the blood-CSF and blood-brain barriers in the Gunn rat. PLoS One 2011; 6:e16165. [PMID: 21297965 PMCID: PMC3031532 DOI: 10.1371/journal.pone.0016165] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 12/07/2010] [Indexed: 01/03/2023] Open
Abstract
Accumulation of unconjugated bilirubin (UCB) in the brain causes bilirubin encephalopathy. Pgp (ABCb1) and Mrp1 (ABCc1), highly expressed in the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) respectively, may modulate the accumulation of UCB in brain. We examined the effect of prolonged exposure to elevated concentrations of UCB on expression of the two transporters in homozygous, jaundiced (jj) Gunn rats compared to heterozygous, not jaundiced (Jj) littermates at different developmental stages (2, 9, 17 and 60 days after birth). BBB Pgp protein expression was low in both jj and Jj pups at 9 days (about 16-27% of adult values), despite the up-regulation in jj animals (2 and 1.3 fold higher than age matched Jj animals at P9 and P17-P60, respectively); Mrp1 protein expression was barely detectable. Conversely, at the BCSFB Mrp1 protein expression was rather high (60-70% of the adult values) in both jj and Jj at P2, but was markedly (50%) down-regulated in jj pups starting at P9, particularly in the 4(th) ventricle choroid plexuses: Pgp was almost undetectable. The Mrp1 protein down regulation was accompanied by a modest up-regulation of mRNA, suggesting a translational rather than a transcriptional inhibition. In vitro exposure of choroid plexus epithelial cells obtained from normal rats to UCB, also resulted in a down-regulation of Mrp1 protein. These data suggest that down-regulation of Mrp1 protein at the BSCFB, resulting from a direct effect of UCB on epithelial cells, may impact the Mrp1-mediated neuroprotective functions of the blood-cerebrospinal fluid barrier and actually potentiate UCB neurotoxicity.
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22
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Yang Z, Philips JD, Doty RT, Giraudi P, Ostrow JD, Tiribelli C, Smith A, Abkowitz JL. Kinetics and specificity of feline leukemia virus subgroup C receptor (FLVCR) export function and its dependence on hemopexin. J Biol Chem 2010; 285:28874-82. [PMID: 20610401 DOI: 10.1074/jbc.m110.119131] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The feline leukemia virus subgroup C receptor (FLVCR) is a heme export protein that is required for proerythroblast survival and facilitates macrophage heme iron recycling. However, its mechanism of heme export and substrate specificity are uncharacterized. Using [(55)Fe]heme and the fluorescent heme analog zinc mesoporphyrin, we investigated whether export by FLVCR depends on the availability and avidity of extracellular heme-binding proteins. Export was 100-fold more efficient when the medium contained hemopexin (K(d) < 1 pm) compared with albumin (K(d) = 5 nm) at the same concentration and was not detectable when the medium lacked heme-binding proteins. Besides heme, FLVCR could export other cyclic planar porphyrins, such as protoporphyrin IX and coproporphyrin. However, FLVCR has a narrow substrate range because unconjugated bilirubin, the primary breakdown product of heme, was not transported. As neither protoporphyrin IX nor coproporphyrin export improved with extracellular hemopexin (versus albumin), our observations further suggest that hemopexin, an abundant protein with a serum concentration (6.7-25 mum) equivalent to that of the iron transport protein transferrin (22-31 mum), by accepting heme from FLVCR and targeting it to the liver, might regulate macrophage heme export and heme iron recycling in vivo. Final studies show that hemopexin directly interacts with FLVCR, which also helps explain why FLVCR, in contrast to some major facilitator superfamily members, does not function as a bidirectional gradient-dependent transporter. Together, these data argue that hemopexin has a role in assuring systemic iron balance during homeostasis in addition to its established role as a scavenger during internal bleeding or hemolysis.
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Affiliation(s)
- Zhantao Yang
- Division of Hematology, Department of Medicine, University of Washington, Seattle, Washington 98195-7710, USA
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23
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Vaidya SS, Walsh SW, Gerk PM. Formation and efflux of ATP-binding cassette transporter substrate 2,4-dinitrophenyl-S-glutathione from cultured human term placental villous tissue fragments. Mol Pharm 2010; 6:1689-702. [PMID: 19397308 DOI: 10.1021/mp900019z] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Upon exposure to 1-chloro-2,4-dinitrobenzene (CDNB), the human placental tissue forms its glutathione conjugate 2,4-dinitrophenyl-S-glutathione (DNP-SG). The purpose of this study was to investigate the involvement of human placental ATP-binding cassette (ABC) transporters in the efflux of DNP-SG. Placental tissue samples were obtained from pregnant patients undergoing C-section deliveries following normal pregnancies; villous tissue was cultured in suspension, and DNP-SG formation and efflux upon exposure to 100 microM CDNB were measured by HPLC. DNP-SG efflux decreased by 69.1 (+/-11.3)%, 51.1 (+/-5.4)%, 56.7 (+/-8.3)% and 53.6 (+/-10.8)% (p < 0.05) in the presence of 5 mM sodium orthovanadate (ATPase inhibitor), 100 microM MK571 (MRP-inhibitor), 1 mM dipyridamole (BCRP/P-gp/MRP1-inhibitor) and 100 microM verapamil (P-gp/MRP1 inhibitor) respectively, without any change in DNP-SG formation, total tissue glutathione, GSH/GSSG ratio, tissue integrity or tissue viability. These data clearly established the role of ABC transporters in the human placental efflux of DNP-SG. To investigate the contribution of various ABC transporters toward DNP-SG transport, ATP-dependent transport of 3H-DNP-SG was determined in Sf9 membrane vesicles overexpressing P-gp, BCRP and the MRP proteins. MRP1-mediated DNP-SG transport was inhibited in the presence of sodium orthovanadate, MK571, dipyridamole and verapamil in the presence of glutathione. Furthermore, MRP1-mediated transport [K(t) = 11.3 +/- 1.3 microM and v(max) = 86.7 +/- 1.9 pmol/mg/min] was a high-affinity process compared to MRP2-mediated transport [K(t) = 168 +/- 7 microM and v(max) = 1367 +/- 18 pmol/mg/min]. The inhibition pattern and the kinetics of DNP-SG efflux in the placental villous tissue were consistent with MRP1-mediated DNP-SG efflux, suggesting a functional role and an apical localization for an MRP1-like transporter in the human placental syncytiotrophoblast.
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Affiliation(s)
- Soniya S Vaidya
- Departments of Pharmaceutics and Obstetrics & Gynecology, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, Virginia 23298-0533, USA
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24
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van de Ven R, Oerlemans R, van der Heijden JW, Scheffer GL, de Gruijl TD, Jansen G, Scheper RJ. ABC drug transporters and immunity: novel therapeutic targets in autoimmunity and cancer. J Leukoc Biol 2009; 86:1075-87. [PMID: 19745159 DOI: 10.1189/jlb.0309147] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
ABC transporters were identified originally for their contribution to clinical MDR as a result of their capacity to extrude various unrelated cytotoxic drugs. More recent reports have shown that ABC transporters can play important roles in the development, differentiation, and maturation of immune cells and are involved in migration of immune effector cells to sites of inflammation. Many of the currently identified, endogenous ABC transporter substrates have immunostimulating effects. Increasing the expression of ABC transporters on immune cells and thereby enhancing immune cell development or functionality may be beneficial to immunotherapy in the field of oncology. On the contrary, in the treatment of autoimmune diseases, blockade of these transporters may prove beneficial, as it could dampen disease activity by compromising immune effector cell functions. This review will focus on the expression, regulation, and substrate specificity of ABC transporters in relation to functional activities of immune effector cells and discusses implications for the treatment of cancer on the one hand and autoimmune diseases on the other.
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Affiliation(s)
- Rieneke van de Ven
- Department of Pathology, VU University Medical Center/Cancer Center Amsterdam, Amsterdam, Zuid Holland 1081 HV The Netherlands
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25
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Abstract
Unconjugated bilirubin (UCB) injury to glial cells leads to the secretion of glutamate and elicits a typical inflammatory response. Release of pro-inflammatory cytokines may influence gliogenesis and neurogenesis, and lead to deficits in learning and memory. Glutamate metabolism dysregulation and overexpression of tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta are consistent with schizophrenia neuropathology. Recently, an increased prevalence of schizophrenia was reported in individuals with Gilbert's syndrome and among those who have had elevated levels of UCB in the neonatal life. In this review, we explore the reactivity of astrocytes, neurons and microglia to UCB, the cascade of events implicated in the immunostimulant effects of UCB, as well as the role of each nerve cell type and maturation state in the neuropathology of UCB. Identification of the signaling events promoted by UCB will be relevant for developing novel therapies that might reduce the risk of brain injury and disabilities.
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The cytotoxic effect of unconjugated bilirubin in human neuroblastoma SH-SY5Y cells is modulated by the expression level of MRP1 but not MDR1. Biochem J 2008; 417:305-12. [DOI: 10.1042/bj20080918] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In vitro and in vivo studies have demonstrated that UCB (unconjugated bilirubin) is neurotoxic. Although previous studies suggested that both MRP1 (multidrug resistance-associated protein 1) and MDR1 (multidrug resistance protein 1) may protect cells against accumulation of UCB, direct comparison of their role in UCB transport was never performed. To this end, we used an inducible siRNA (small interfering RNA) expression system to silence the expression of MRP1 and MDR1 in human neuroblastoma SH-SY5Y cells. The effects of in vitro exposure to clinically-relevant levels of unbound UCB were compared between unsilenced (control) cells and cells with similar reductions in the expression of MRP1 or MDR1, documented by RT–PCR (reverse transcription–PCR) (mRNA), immunoblotting (protein), and for MDR1, the enhanced net uptake of a specific fluorescent substrate. Cytotoxicity was assessed by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] test. MRP1-deficient cells accumulated significantly more UCB and suffered greater cytotoxicity than controls. By contrast, MDR1-deficient cells exhibited UCB uptake and cytotoxicity comparable with controls. At intermediate levels of silencing, the increased susceptibility to UCB toxicity closely correlated with the decrease in the expression of MRP1, but not of MDR1. These data support the concept that limitation of cellular UCB accumulation, due to UCB export mediated by MRP1, but not MDR1, plays an important role in preventing bilirubin encephalopathy in the newborn.
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27
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Gazzin S, Strazielle N, Schmitt C, Fevre-Montange M, Ostrow JD, Tiribelli C, Ghersi-Egea JF. Differential expression of the multidrug resistance-related proteins ABCb1 and ABCc1 between blood-brain interfaces. J Comp Neurol 2008; 510:497-507. [PMID: 18680196 DOI: 10.1002/cne.21808] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Cerebral homeostasis results from the presence of the protective blood-brain and blood-cerebrospinal fluid barriers located respectively at the brain capillary endothelium and the choroid plexus epithelium. ABCb1 (Pgp) and ABCc1 (Mrp1) transporters are two major proteins of neuroprotection whose localization and functional significance at both barriers remain partly unsettled. We conducted a comparative analysis of their relative protein content between the two blood-brain interfaces. Microvessels and choroid plexuses located in the fourth and lateral ventricles were isolated from developing and adult rat brains, and whole homogenates were submitted to quantitative Western blot analysis by using standard curves generated from one of the samples. In adult, choroid plexus-associated Pgp content was less than 0.5% of the level in microvessels, whereas Mrp1 content in microvessels was 4% of that in the fourth ventricle choroid plexus. Pgp but not Mrp1 was enriched in microvessels over parenchyma. In choroid plexuses, Mrp1 displayed a basolateral epithelial localization, and reached its high adult protein level, early during postnatal development. In postnatal as in adult microvessels, Pgp localization appeared luminal. However, by contrast to Mrp1, the level of this transporter increased 4.6-fold between 9-day-old and adult animals. Western blot analysis of human samples confirmed the mirror image of Pgp and Mrp1 expression between the two barriers. We conclude that there are major differences in the mechanisms by which blood-brain interfaces fulfill their neuroprotective functions. The data also highlight the significance of the neuroprotective function of the choroid plexus during brain maturation, when the microvasculature is still developing.
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Affiliation(s)
- Silvia Gazzin
- INSERM U842, Université de Lyon, Lyon 1, Faculté de Médecine Laennec, F-69372 Lyon, France
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28
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Abstract
Elucidation of the key mechanisms that confer interindividual differences in drug response remains an important focus of drug disposition and clinical pharmacology research. We now know both environmental and host genetic factors contribute to the apparent variability in drug efficacy or in some cases, toxicity. In addition to the widely studied and recognized genes involved in the metabolism of drugs in clinical use today, we now recognize that membrane-bound proteins, broadly referred to as transporters, may be equally as important to the disposition of a substrate drug, and that genetic variation in drug transporter genes may be a major contributor of the apparent intersubject variation in drug response, both in terms of attained plasma and tissue drug level at target sites of action. Of particular relevance to drug disposition are members of the ATP Binding Cassette (ABC) superfamily of efflux transporters. In this review a comprehensive assessment and annotation of recent findings in relation to genetic variation in the Multidrug Resistance Proteins 1-5 (ABCC1-5) and Breast Cancer Resistance Protein (ABCG2) are described, with particular emphasis on the impact of such transporter genetic variation to drug disposition or efficacy.
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Affiliation(s)
- Ulrike Gradhand
- Division of Clinical Pharmacology, Department of Medicine, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Canada
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Zelenka J, Lenícek M, Muchová L, Jirsa M, Kudla M, Balaz P, Zadinová M, Ostrow JD, Wong RJ, Vítek L. Highly sensitive method for quantitative determination of bilirubin in biological fluids and tissues. J Chromatogr B Analyt Technol Biomed Life Sci 2008; 867:37-42. [PMID: 18373963 DOI: 10.1016/j.jchromb.2008.03.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2007] [Revised: 02/11/2008] [Accepted: 03/05/2008] [Indexed: 11/24/2022]
Abstract
Unconjugated bilirubin (UCB) exhibits potent antioxidant and cytoprotective properties, but causes apoptosis and cytotoxicity at pathologically elevated concentrations. Accurate measurement of UCB concentrations in cells, fluids and tissues is needed to evaluate its role in redox regulation, prevention of atherosclerotic and malignant diseases, and bilirubin encephalopathy. In the present study, we developed and validated a highly sensitive method for tissue UCB determinations. UCB was extracted from rat organs with chloroform/methanol/hexane at pH 6.2 and then partitioned into a minute volume of alkaline buffer that was subjected to HPLC using an octyl reverse phase (RP) column. Addition of mesobilirubin as an internal standard corrected for losses of UCB during extraction. Recoveries averaged 75+/-5%. The detection limit was 10pmol UCB/g wet tissue. Variance was +/-2.5%. When used to measure UCB concentrations in tissues of jaundiced Gunn rats, this procedure yielded UCB levels directly comparable to published methods, and accurately determined very low tissue bilirubin concentrations (</=40pmol UCB/g tissue) in non-jaundiced rats.
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Affiliation(s)
- Jaroslav Zelenka
- Institute of Clinical Biochemistry and Laboratory Diagnostics, 1st Faculty of Medicine, Charles University in Prague, Czech Republic
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Sequeira D, Watchko JF, Daood MJ, O'Day TL, Mahmood B. Unconjugated bilirubin efflux by bovine brain microvascular endothelial cells in vitro. Pediatr Crit Care Med 2007; 8:570-5. [PMID: 17906594 DOI: 10.1097/01.pcc.0000288716.63685.1b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The passage of unconjugated bilirubin (UCB) across the blood-brain barrier into the central nervous system is a crucial first step in the development of kernicterus. The objective of the current study was to characterize the passage of UCB across primary bovine brain microvascular endothelial cell (BBMVEC) monolayers in vitro. DESIGN Experimental study. SETTING Research institute. SUBJECTS BBMVECs. INTERVENTIONS Tritiated UCB (H-UCB) transport at 60, 80, 100, 200, 300, and 400 nM concentrations was tested in both the apical to basolateral (A--> B) and basolateral to apical (B-->A) directions in BBMVEC monolayers in vitro with or without preincubation with pharmacologic active transport inhibitors cyclosporine A, indomethacin, or MK571. MEASUREMENTS AND MAIN RESULTS The rate of H-UCB transport in the B-->A direction was 6.2- to 7.3-fold higher than in the A-->B direction, suggesting active efflux of UCB. Cyclosporine A (5 microM), a model inhibitor of P-glycoprotein, enhanced A-->B while decreasing B-->A UCB transport, resulting in an overall decrease in BBMVEC UCB efflux of between 46% and 54%. Indomethacin (10 microM) and MK-571 (50 microM), respectively a substrate and potent inhibitor of multidrug resistance-associated protein-1, had no effect. CONCLUSIONS We conclude that 1) UCB is transported by BBMVEC monolayers in vitro in a net B-->A direction (i.e., active efflux); and 2) cyclosporine A partially inhibits such transport. We speculate that the blood-brain barrier limits the passage and central nervous system retention of UCB by active transport and that this may be accounted in part by P-glycoprotein.
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Affiliation(s)
- Deryk Sequeira
- Department of Pediatrics, University of Pittsburgh School of Medicine, Magee-Womens Research Institute, Pittsburgh, PA, USA
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31
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Tamura A, An R, Onishi Y, Ishikawa T. [Role of ABC transporters in porphyrin biosynthesis and heme metabolism]. Nihon Yakurigaku Zasshi 2007; 130:270-274. [PMID: 17938511 DOI: 10.1254/fpj.130.270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Köck K, Grube M, Jedlitschky G, Oevermann L, Siegmund W, Ritter CA, Kroemer HK. Expression of adenosine triphosphate-binding cassette (ABC) drug transporters in peripheral blood cells: relevance for physiology and pharmacotherapy. Clin Pharmacokinet 2007; 46:449-70. [PMID: 17518506 DOI: 10.2165/00003088-200746060-00001] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Adenosine triphosphate-binding cassette (ABC)-type transport proteins were initially described for their ability to reduce intracellular concentrations of anticancer compounds, thereby conferring drug resistance. In recent years, expression of this type of proteins has also been reported in numerous cell types under physiological conditions; here, these transporters are often reported to alter systemic and local drug disposition (e.g. in the brain or the gastrointestinal tract). In this context, peripheral blood cells have also been found to express several ABC-type transporters. While erythrocytes mainly express multidrug resistance protein (MRP) 1, MRP4 and MRP5, which are discussed with regard to their involvement in glutathione homeostasis (MRP1) and in the efflux of cyclic nucleotides (MRP4 and MRP5), leukocytes also express P-glycoprotein and breast cancer resistance protein. In the latter cell types, the main function of efflux transporters may be protection against toxins, as these cells demonstrate a very high turnover rate. In platelets, only two ABC transporters have been described so far. Besides MRP1, platelets express relatively high amounts of MRP4 not only in the plasma membrane but also in the membrane of dense granules, suggesting relevance for mediator storage. In addition to its physiological function, ABC transporter expression in these structures can be of pharmacological relevance since all systemic drugs reach their targets via circulation, thereby enabling interaction of the therapeutic agent with peripheral blood cells. Moreover, both intended effects and unwanted side effects occur in peripheral blood cells, and intracellular micropharmacokinetics can be affected by these transport proteins. The present review summarises the data available on expression of ABC transport proteins in peripheral blood cells.
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Affiliation(s)
- Kathleen Köck
- Department of Pharmacology, Research Center of Pharmacology and Experimental Therapeutics, Ernst Moritz Arndt University, Greifswald, Germany
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Falcão AS, Bellarosa C, Fernandes A, Brito MA, Silva RFM, Tiribelli C, Brites D. Role of multidrug resistance-associated protein 1 expression in the in vitro susceptibility of rat nerve cell to unconjugated bilirubin. Neuroscience 2007; 144:878-88. [PMID: 17141959 DOI: 10.1016/j.neuroscience.2006.10.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2006] [Revised: 10/10/2006] [Accepted: 10/14/2006] [Indexed: 12/26/2022]
Abstract
Nerve cell injury by unconjugated bilirubin (UCB) has been implicated in brain damage during neonatal hyperbilirubinemia, particularly in the preterm newborn. Recently, it was shown that UCB is a substrate for the multidrug resistance-associated protein 1 (Mrp1), an ATP-dependent efflux pump, which may decrease UCB intracellular levels. To obtain a further insight into the role of Mrp1 in the increased vulnerability of immature cells to UCB, we evaluated the mRNA and the protein levels of Mrp1 throughout differentiation in primary cultures of rat neurons and astrocytes. Furthermore, in order to provide supportive evidence for the role of Mrp1 in the protection of nerve cells from UCB-induced effects, we evaluated cell susceptibility to UCB when Mrp1 was inhibited with MK571 ((E)-3-[[[3-[2-(7-chloro-2-quinolinyl) ethenyl]phenyl]-[[3-dimethylamino)-3-oxopropyl]thio]methyl]thio]-propanoic acid). The results are the first to demonstrate that Mrp1 is expressed in neurons and that both mRNA and protein levels of Mrp1 increase with cell differentiation. Additionally, inhibition of Mrp1 was associated with an increase in UCB toxic effects, namely cell death, cell dysfunction, and secretion of interleukin (IL)-1beta, tumor necrosis factor (TNF)-alpha, as well as of glutamate. These results point to a novel role of Mrp1 in the susceptibility of premature babies to UCB encephalopathy, and provide a startup point for the development of a new therapeutic strategy.
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Affiliation(s)
- A S Falcão
- Centro de Patogénese Molecular-UBMBE, Faculdade de Farmácia, University of Lisbon, Avenida Professor Gama Pinto, 1649-003 Lisbon, Portugal
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Choudhuri S, Klaassen CD. Structure, function, expression, genomic organization, and single nucleotide polymorphisms of human ABCB1 (MDR1), ABCC (MRP), and ABCG2 (BCRP) efflux transporters. Int J Toxicol 2006; 25:231-59. [PMID: 16815813 DOI: 10.1080/10915810600746023] [Citation(s) in RCA: 257] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The ATP-binding cassette (ABC) transporters constitute a large family of membrane proteins, which transport a variety of compounds through the membrane against a concentration gradient at the cost of ATP hydrolysis. Substrates of the ABC transporters include lipids, bile acids, xenobiotics, and peptides for antigen presentation. As they transport exogenous and endogenous compounds, they reduce the body load of potentially harmful substances. One by-product of such protective function is that they also eliminate various useful drugs from the body, causing drug resistance. This review is a brief summary of the structure, function, and expression of the important drug resistance-conferring members belonging to three subfamilies of the human ABC family; these are ABCB1 (MDR1/P-glycoprotein of subfamily ABCB), subfamily ABCC (MRPs), and ABCG2 (BCRP of subfamily ABCG), which are expressed in various organs. In the text, the transporter symbol that carries the subfamily name (such as ABCB1, ABCC1, etc.) is used interchangeably with the corresponding original names, such as MDR1P-glycoprotein, MRP1, etc., respectively. Both nomenclatures are maintained in the text because both are still used in the transporter literature. This helps readers relate various names that they encounter in the literature. It now appears that P-glycoprotein, MRP1, MRP2, and BCRP can explain the phenomenon of multidrug resistance in all cell lines analyzed thus far. Also discussed are the gene structure, regulation of expression, and various polymorphisms in these genes. Because genetic polymorphism is thought to underlie interindividual differences, including their response to drugs and other xenobiotics, the importance of polymorphism in these genes is also discussed.
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Affiliation(s)
- Supratim Choudhuri
- Division of Biotechnology and GRAS Notice Review, Office of Food Additive Safety, Center for Food Safety and Nutrition, U.S. Food and Drug Administration, College Park, Maryland, USA.
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Abstract
This article describes new findings concerning the basic science of bilirubin neurotoxicity, new considerations of the definition of clinical kernicterus, and new and useful tools to diagnose kernicterus in older children, and discusses treatments for kernicterus beyond the newborn period and why proper diagnosis is important.
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Affiliation(s)
- Steven M Shapiro
- Division of Child Neurology, Department of Neurology, Virginia Commonwealth University Medical Center, Virginia Commonwealth University, Richmond, 23298-0211, USA.
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36
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Dallas S, Miller DS, Bendayan R. Multidrug Resistance-Associated Proteins: Expression and Function in the Central Nervous System. Pharmacol Rev 2006; 58:140-61. [PMID: 16714484 DOI: 10.1124/pr.58.2.3] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Drug delivery to the brain is highly restricted, since compounds must cross a series of structural and metabolic barriers to reach their final destination, often a cellular compartment such as neurons, microglia, or astrocytes. The primary barriers to the central nervous system are the blood-brain and blood-cerebrospinal fluid barriers. Through structural modifications, including the presence of tight junctions that greatly limit paracellular transport, the cells that make up these barriers restrict diffusion of many pharmaceutically active compounds. In addition, the cells that comprise the blood-brain and blood-cerebrospinal fluid barriers express multiple ATP-dependent, membrane-bound, efflux transporters, such as members of the multidrug resistance-associated protein (MRP) family, which contribute to lowered drug accumulation. A relatively new concept in brain drug distribution just beginning to be explored is the possibility that cellular components of the brain parenchyma could act as a "second" barrier to brain permeation of pharmacological agents via expression of many of the same transporters. Indeed, efflux transporters expressed in brain parenchyma may facilitate the overall export of xenobiotics from the central nervous system, essentially handing them off to the barrier tissues. We propose that these primary and secondary barriers work in tandem to limit overall accumulation and distribution of xenobiotics in the central nervous system. The present review summarizes recent knowledge in this area and emphasizes the clinical significance of MRP transporter expression in a variety of neurological disorders.
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Affiliation(s)
- Shannon Dallas
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, NIH, Research Triangle Park, NC, USA
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37
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Wennberg RP, Ahlfors CE, Bhutani VK, Johnson LH, Shapiro SM. Toward understanding kernicterus: a challenge to improve the management of jaundiced newborns. Pediatrics 2006; 117:474-85. [PMID: 16452368 DOI: 10.1542/peds.2005-0395] [Citation(s) in RCA: 179] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE We sought to evaluate the sensitivity and specificity of total serum bilirubin concentration (TSB) and free (unbound) bilirubin concentration (Bf) as predictors of risk for bilirubin toxicity and kernicterus and to examine consistency between these findings and proposed mechanisms of bilirubin transport and brain uptake. METHODS A review of literature was undertaken to define basic principles of bilirubin transport and brain uptake leading to neurotoxicity. We then reviewed experimental and clinical evidence that relate TSB or Bf to risk for bilirubin toxicity and kernicterus. RESULTS There are insufficient published data to precisely define sensitivity and specificity of either TSB or Bf in determining risk for acute bilirubin neurotoxicity or chronic sequelae (kernicterus). However, available laboratory and clinical evidence indicate that Bf is better than TSB in discriminating risk for bilirubin toxicity in patients with severe hyperbilirubinemia. These findings are consistent with basic pharmacokinetic principles involved in bilirubin transport and tissue uptake. CONCLUSIONS Experimental and clinical data strongly suggest that measurement of Bf in newborns with hyperbilirubinemia will improve risk assessment for neurotoxicity, which emphasizes the need for additional clinical evaluation relating Bf and TSB to acute bilirubin toxicity and long-term outcome. We speculate that establishing risk thresholds for neurotoxicity by using newer methods for measuring Bf in minimally diluted serum samples will improve the sensitivity and specificity of serum indicators for treating hyperbilirubinemia, thus reducing unnecessary aggressive intervention and associated cost and morbidity.
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Affiliation(s)
- Richard P Wennberg
- Division of Neonatology, Department of Pediatrics, University of Washington, Box 356320, Seattle, WA 98195, USA.
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Calligaris S, Cekic D, Roca-Burgos L, Gerin F, Mazzone G, Ostrow JD, Tiribelli C. Multidrug resistance associated protein 1 protects against bilirubin-induced cytotoxicity. FEBS Lett 2006; 580:1355-9. [PMID: 16458308 DOI: 10.1016/j.febslet.2006.01.056] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/18/2006] [Accepted: 01/19/2006] [Indexed: 11/22/2022]
Abstract
We have shown that multidrug resistance associated protein 1 (MRP1) mediates ATP-dependent extrusion of bilirubin, possibly limiting its potentially toxic accumulation in cells. To determine directly if Mrp1 protects cells against unconjugated bilirubin (UCB) toxicity, mouse embryo fibroblasts (MEF) were isolated from Mrp1 knockout (-/-) mice and their wild type (WT) (+/+) littermates. Compared to WT cells, cultured MEF (-/-) cells exposed to 40-140 nM unbound [H3]-bilirubin accumulated twice as much [H3]-bilirubin (P<0.01). This was associated with greater, dose-related cytotoxicity, assessed by the methylthiazoletetrazolium test, lactate dehydrogenase release and cellular ATP content. The data confirm that Mrp1 limits intracellular accumulation of UCB and thus decreases its cytotoxicity.
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Affiliation(s)
- Sebastián Calligaris
- Centro Studi Fegato, Bld Q, AREA Science Park, Basovizza Campus, ss 14 Km 163.5, 34012 Trieste, Italy
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Swerts K, De Moerloose B, Dhooge C, Laureys G, Benoit Y, Philippé J. Prognostic significance of multidrug resistance-related proteins in childhood acute lymphoblastic leukaemia. Eur J Cancer 2005; 42:295-309. [PMID: 16324833 DOI: 10.1016/j.ejca.2005.09.017] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 09/15/2005] [Accepted: 09/28/2005] [Indexed: 11/24/2022]
Abstract
An important problem in the treatment of children with acute lymphoblastic leukaemia (ALL) is pre-existent or acquired resistance to structurally and functionally unrelated chemotherapeutic compounds. Various cellular mechanisms can give rise to multidrug resistance (MDR). Best studied is the transmembrane protein-mediated efflux of cytotoxic compounds that leads to decreased cellular drug accumulation and toxicity. Several MDR-related efflux pumps have been characterised, including P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), breast cancer resistance protein (BCRP) and lung resistance protein (LRP). P-gp expression and/or activity has been associated with unfavourable outcome in paediatric ALL patients, whereas MRP1 and BCRP do not seem to play a major role. LRP might contribute to drug resistance in B-lineage ALL, but larger studies are needed to confirm these results. The present review summarises the current knowledge concerning multidrug resistance-related proteins and focuses on the clinical relevance and prognostic value of these efflux pumps in childhood ALL.
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Affiliation(s)
- Katrien Swerts
- Department of Paediatric Haematology and Oncology, Ghent University Hospital, De Pintelaan 185, B-9000 Ghent, Belgium.
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Sahi J. Use ofin vitrotransporter assays to understand hepatic and renal disposition of new drug candidates. Expert Opin Drug Metab Toxicol 2005; 1:409-27. [PMID: 16863453 DOI: 10.1517/17425255.1.3.409] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Hepatic and renal transporters contribute to the uptake, secretion and reabsorption of endogenous compounds, xenobiotics and their metabolites and have been implicated in drug-drug interactions and toxicities. Characterising the renal and hepatic disposition of drug candidates early in development would lead to more rational drug design, as chemotypes with 'ideal' pharmacokinetic characteristics could be identified and further refined. Because transporters are often organ specific, 'custom' transporter panels need to be identified for each major organ and chemotype to be evaluated, and appropriate studies planned. This review outlines the major renal and hepatic transporters and some of the in vitro transporter reagents, assays and processes that can be used to evaluate the renal and hepatic disposition of new chemical entities during drug discovery and development.
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Affiliation(s)
- Jasminder Sahi
- CELLZDIRECT, 480 Hillsboro Street, Pittsboro, NC 27312, USA.
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Tiribelli C, Ostrow JD. The molecular basis of bilirubin encephalopathy and toxicity: report of an EASL Single Topic Conference, Trieste, Italy, 1-2 October, 2004. J Hepatol 2005; 43:156-66. [PMID: 15921815 DOI: 10.1016/j.jhep.2005.04.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Claudio Tiribelli
- Centro Studi Fegato, Bldg. Q, AREA Science Park, Basovizza and Department of BBCM, University of Trieste, 34012 Trieste, Italy.
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43
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Tian Q, Zhang J, Chan E, Duan W, Zhou S. Multidrug resistance proteins (MRPs) and implication in drug development. Drug Dev Res 2005. [DOI: 10.1002/ddr.10427] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
Drug-metabolizing enzymes, drug transporters and drug targets play significant roles as determinants of drug efficacy and toxicity. Their genetic polymorphisms often affect the expression and function of their products and are expected to become surrogate markers to predict the response to drugs in individual patients. With the sequencing of the human genome, it has been estimated that approximately 500–1200 genes code for drug transporters and, recently, there have been significant and rapid advances in the research on the relationships between genetic polymorphisms of drug transporters and interindividual variation of drug disposition. At present, the clinical studies of multi-drug resistance protein 1 (MDR1, P-glycoprotein, ABCB1), which belongs to the ATP-binding cassette (ABC) superfamily, are the most comprehensive among the ABC transporters, but clinical investigations on other drug transporters are currently being performed around the world. MDR1 can be said to be the most important drug transporter, since clinical reports have suggested that it regulates the disposition of various types of clinically important drugs, but in vitro investigations or animal experiments have strongly suggested that the members of the multi-drug resistance-associated protein (MRP) subfamily can also become key molecules for pharmacotherapy. In addition to those, breast cancer resistance protein (BCRP, ABCG2), another ABC transporter, is well known as a key molecule of multi-drug resistance to several anticancer agents. However, this review focuses on the latest information on the pharmacogenetics of the MDR and MRP subfamilies, and its impact on pharmacotherapy is discussed.
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Affiliation(s)
- Noboru Okamura
- Kobe University Graduate School of Medicine, Department of Clinical Evaluation of Pharmacotherapy, Kobe University Graduate School of Medicine, 1-5-6, Minatojima-minamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Toshiyuki Sakaeda
- Kobe University, Department of Hospital Pharmacy, School of Medicine, Kobe University, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Katsuhiko Okumura
- Kobe University, Department of Hospital Pharmacy, School of Medicine, Kobe University, 7-5-2, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
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