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Hansmann E, Mennillo E, Yoda E, Verreault M, Barbier O, Chen S, Tukey RH. Differential Role of Liver X Receptor (LXR) α and LXR β in the Regulation of UDP-Glucuronosyltransferase 1A1 in Humanized UGT1 Mice. Drug Metab Dispos 2020; 48:255-263. [PMID: 31980500 DOI: 10.1124/dmd.119.090068] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 01/14/2020] [Indexed: 12/17/2022] Open
Abstract
Liver X receptors (LXRs), LXRα and LXRβ, are nuclear receptors that regulate the metabolism of cholesterol and bile acids and are activated by oxysterols. Humanized UGT1 (hUGT1) mice express the 9-human UGT1A genes associated with the UGT1 locus in a Ugt1-null background. The expression of UGT1A1 is developmentally delayed in the liver and intestines, resulting in the accumulation of serum bilirubin during the neonatal period. Induction of UGT1A1 in newborn hUGT1 mice leads to rapid reduction in total serum bilirubin (TSB) levels, a phenotype measurement that allows for an accurate prediction on UGT1A1 expression. When neonatal hUGT1 mice were treated by oral gavage with the LXR agonist T0901317, TSB levels were dramatically reduced. To determine the LXR contribution to the induction of UGT1A1 and the lowering of TSB levels, experiments were conducted in neonatal hUGT1/Lxrα -/- , hUGT1/Lxrβ -/- , and hUGT1/Lxrαβ -/- mice treated with T0901317. Induction of liver UGT1A1 was dependent upon LXRα, with the induction pattern paralleling induction of LXRα-specific stearoyl CoA desaturase 1. However, the actions of T0901317 were also shown to display a lack of specificity for LXR, with the induction of liver UGT1A1 in hUGT1/Lxrαβ -/- mice, a result associated with activation of both pregnane X receptor and constitutive androstane receptor. However, the LXR agonist GW3965 was highly selective toward LXRα, showing no impact on lowering TSB values or inducing UGT1A1 in hUGT1/Lxrα -/- mice. An LXR-specific enhancer site on the UGT1A1 gene was identified, along with convincing evidence that LXRα is crucial in maintaining constitutive expression of UGT1A1 in adult hUGT1 mice. SIGNIFICANCE STATEMENT: It has been established that activation of LXRα, and not LXRβ, is responsible for the induction of liver UGT1A1 and metabolism of serum bilirubin in neonatal hUGT1 mice. Although induction of the human UGT1A1 gene is initiated at a newly characterized LXR enhancer site, allelic deletion of the Lxrα gene drastically reduces the constitutive expression of liver UGT1A1 in adult hUGT1 mice. Combined, these findings indicate that LXRα is critical for the developmental expression of UGT1A1.
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Affiliation(s)
- Eva Hansmann
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Elvira Mennillo
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Emiko Yoda
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Mélanie Verreault
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Olivier Barbier
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Shujuan Chen
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
| | - Robert H Tukey
- Laboratory of Environmental Toxicology, Department of Pharmacology, University of California, San Diego, La Jolla, California (E.H., E.M., E.Y., S.C., R.H.T.); Division of Health Chemistry, Department of Healthcare and Regulatory Sciences, School of Pharmacy, Showa University, Shinagawa-ku, Tokyo, Japan (E.Y.); and Laboratory of Moléculaire Pharmacology, Centre de Recherche du CHU de Québec, Faculté of Pharmacie, Université Laval Québec, Québec, Canada (M.V., O.B.)
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Choudhary M, Ismail EN, Yao PL, Tayyari F, Radu RA, Nusinowitz S, Boulton ME, Apte RS, Ruberti JW, Handa JT, Tontonoz P, Malek G. LXRs regulate features of age-related macular degeneration and may be a potential therapeutic target. JCI Insight 2020; 5:131928. [PMID: 31829999 DOI: 10.1172/jci.insight.131928] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 12/05/2019] [Indexed: 12/11/2022] Open
Abstract
Effective treatments and animal models for the most prevalent neurodegenerative form of blindness in elderly people, called age-related macular degeneration (AMD), are lacking. Genome-wide association studies have identified lipid metabolism and inflammation as AMD-associated pathogenic pathways. Given liver X receptors (LXRs), encoded by the nuclear receptor subfamily 1 group H members 2 and 3 (NR1H3 and NR1H2), are master regulators of these pathways, herein we investigated the role of LXR in human and mouse eyes as a function of age and disease and tested the therapeutic potential of targeting LXR. We identified immunopositive LXR fragments in human extracellular early dry AMD lesions and a decrease in LXR expression within the retinal pigment epithelium (RPE) as a function of age. Aged mice lacking LXR presented with isoform-dependent ocular pathologies. Specifically, loss of the Nr1h3 isoform resulted in pathobiologies aligned with AMD, supported by compromised visual function, accumulation of native and oxidized lipids in the outer retina, and upregulation of ocular inflammatory cytokines, while absence of Nr1h2 was associated with ocular lipoidal degeneration. LXR activation not only ameliorated lipid accumulation and oxidant-induced injury in RPE cells but also decreased ocular inflammatory markers and lipid deposition in a mouse model, thereby providing translational support for pursuing LXR-active pharmaceuticals as potential therapies for dry AMD.
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Affiliation(s)
- Mayur Choudhary
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Ebraheim N Ismail
- Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA
| | - Pei-Li Yao
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Faryan Tayyari
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Roxana A Radu
- Stein Eye Institute, Department of Ophthalmology, UCLA, Los Angeles, California, USA
| | - Steven Nusinowitz
- Stein Eye Institute, Department of Ophthalmology, UCLA, Los Angeles, California, USA
| | - Michael E Boulton
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rajendra S Apte
- Department of Ophthalmology and Visual Sciences, Washington University in Saint Louis School of Medicine, Saint Louis, Missouri, USA
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University, Boston, Massachusetts, USA
| | - James T Handa
- Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, USA
| | - Peter Tontonoz
- Department of Pathology and Laboratory Medicine, UCLA, Los Angeles, California, USA
| | - Goldis Malek
- Duke Eye Center, Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA.,Department of Pathology, Duke University School of Medicine, Durham, North Carolina, USA
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