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Weiskirchen R, Tacke F. Small heterodimer partner (SHP) links hepatitis C and liver fibrosis: a small protein on the big stage. Liver Int 2015; 35:2218-21. [PMID: 26037155 DOI: 10.1111/liv.12881] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry, University Hospital RWTH Aachen, Aachen, Germany
| | - Frank Tacke
- Department of Medicine III, University Hospital RWTH Aachen, Aachen, Germany
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Abstract
BACKGROUND & AIMS Bile acids are physiological detergents that also activate nuclear receptors to regulate glucose and lipid homeostasis. Cholesterol 7α-hydroxylase (Cyp7a1), the rate-limiting enzyme that converts cholesterol to bile acids, is transcriptionally regulated by bile acids and circadian rhythms. Fasting, nutrients and the circadian clock critically control hepatic bile acid and lipid homeostasis, while circadian misalignment is associated with metabolic syndrome in humans. To delineate these interactions, we employed a sleep disruption model to induce circadian disruption and examined hepatic metabolism with respect to bile acids, lipids and clock gene expression. METHODS B6xC57 mice were maintained on chow or Western diet and were sleep disrupted for 6 hr/day for 5 days. Mice were sacrificed at 4 hr intervals over 24 hr. Hepatic metabolic genes were examined, and bile acid pool and lipid profiles were measured over 24 hr. RESULTS Sleep disruption significantly suppressed circadian expression of core clock genes, genes involved in lipid metabolism, and key regulators of Cyp7a1 as well as Cyp7a1 expression itself. Sleep disruption abolished the peak in serum cholesterol and increased liver and serum free fatty acids. Bile acid pool size was increased while liver bile acids were decreased. ChIP assay revealed HNF4α and Dbp occupancies were suppressed at the Cyp7a1 promoter in sleep-disrupted mice. When coupled with Western diet, sleep disruption abolished liver clock rhythms and elevated free fatty acids. CONCLUSIONS This study suggests that even short-term circadian disruption dramatically alters hepatic clock gene expression, bile acid metabolism and lipid homeostasis to contribute to dyslipidemia.
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Zou A, Lehn S, Magee N, Zhang Y. New Insights into Orphan Nuclear Receptor SHP in Liver Cancer. NUCLEAR RECEPTOR RESEARCH 2015; 2. [PMID: 26504773 PMCID: PMC4618403 DOI: 10.11131/2015/101162] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Small heterodimer partner (SHP; NR0B2) is a unique orphan nuclear receptor (NR) that contains a putative ligand-binding domain but lacks a DNA-binding domain. SHP is a transcriptional corepressor affecting diverse metabolic processes including bile acid synthesis, cholesterol and lipid metabolism, glucose and energy homeostasis, and reproductive biology via interaction with multiple NRs and transcriptional factors (TFs). Hepatocellular carcinoma (HCC) is one of the most deadly human cancers worldwide with few therapeutic options and poor prognosis. Recently, it is becoming clear that SHP plays an antitumor role in the development of liver cancer. In this review, we summarize the most recent findings regarding the new SHP interaction partners, new structural insights into SHP’s gene repressing activity, and SHP protein posttranslational modifications by bile acids. We also discuss the pleiotropic role of SHP in regulating cell proliferation, apoptosis, DNA methylation, and inflammation that are related to antitumor role of SHP in HCC. Improving our understanding of SHP’s antitumor role in the development of liver cancer will provide new insights into developing novel treatments or prevention strategies. Future research will focus on developing more efficacious and specific synthetic SHP ligands for pharmaceutical applications in liver cancer and several metabolic diseases such as hypercholesterolemia, obesity, diabetes, and fatty liver disease.
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Affiliation(s)
- An Zou
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Sarah Lehn
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Nancy Magee
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Yuxia Zhang
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Tsuchiya H, da Costa KA, Lee S, Renga B, Jaeschke H, Yang Z, Orena SJ, Goedken MJ, Zhang Y, Kong B, Lebofsky M, Rudraiah S, Smalling R, Guo G, Fiorucci S, Zeisel SH, Wang L. Interactions Between Nuclear Receptor SHP and FOXA1 Maintain Oscillatory Homocysteine Homeostasis in Mice. Gastroenterology 2015; 148:1012-1023.e14. [PMID: 25701738 PMCID: PMC4409521 DOI: 10.1053/j.gastro.2015.01.045] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Revised: 01/27/2015] [Accepted: 01/30/2015] [Indexed: 12/18/2022]
Abstract
BACKGROUND & AIMS Hyperhomocysteinemia is often associated with liver and metabolic diseases. We studied nuclear receptors that mediate oscillatory control of homocysteine homeostasis in mice. METHODS We studied mice with disruptions in Nr0b2 (called small heterodimer partner [SHP]-null mice), betaine-homocysteine S-methyltransferase (Bhmt), or both genes (BHMT-null/SHP-null mice), along with mice with wild-type copies of these genes (controls). Hyperhomocysteinemia was induced by feeding mice alcohol (National Institute on Alcohol Abuse and Alcoholism binge model) or chow diets along with water containing 0.18% DL-homocysteine. Some mice were placed on diets containing cholic acid (1%) or cholestyramine (2%) or high-fat diets (60%). Serum and livers were collected during a 24-hour light-dark cycle and analyzed by RNA-seq, metabolomic, and quantitative polymerase chain reaction, immunoblot, and chromatin immunoprecipitation assays. RESULTS SHP-null mice had altered timing in expression of genes that regulate homocysteine metabolism compared with control mice. Oscillatory production of S-adenosylmethionine, betaine, choline, phosphocholine, glyceophosphocholine, cystathionine, cysteine, hydrogen sulfide, glutathione disulfide, and glutathione, differed between SHP-null mice and control mice. SHP inhibited transcriptional activation of Bhmt and cystathionine γ-lyase by FOXA1. Expression of Bhmt and cystathionine γ-lyase was decreased when mice were fed cholic acid but increased when they were placed on diets containing cholestyramine or high-fat content. Diets containing ethanol or homocysteine induced hyperhomocysteinemia and glucose intolerance in control, but not SHP-null, mice. In BHMT-null and BHMT-null/SHP-null mice fed a control liquid, lipid vacuoles were observed in livers. Ethanol feeding induced accumulation of macrovesicular lipid vacuoles to the greatest extent in BHMT-null and BHMT-null/SHP-null mice. CONCLUSIONS Disruption of Shp in mice alters timing of expression of genes that regulate homocysteine metabolism and the liver responses to ethanol and homocysteine. SHP inhibits the transcriptional activation of Bhmt and cystathionine γ-lyase by FOXA1.
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Affiliation(s)
- Hiroyuki Tsuchiya
- Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Kerry-Ann da Costa
- Nutrition Research Institute, Department of Nutrition, University of North Carolina at Chapel Hill, North Carolina
| | - Sangmin Lee
- Department of Physiology and Neurobiology and The Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
| | - Barbara Renga
- Dipartimento di Scienze Chirurgiche e Biomediche, University of Perugia, Perugia, Italy
| | - Hartmut Jaeschke
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Zhihong Yang
- Department of Physiology and Neurobiology and The Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut; Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut
| | - Stephen J Orena
- Nutrition Research Institute, Department of Nutrition, University of North Carolina at Chapel Hill, North Carolina
| | | | - Yuxia Zhang
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Bo Kong
- Department of Pharmacology and Toxicology of School of Pharmacy, Rutgers University, Piscataway, New Jersey
| | - Margitta Lebofsky
- Department of Pharmacology, Toxicology & Therapeutics, University of Kansas Medical Center, Kansas City, Kansas
| | - Swetha Rudraiah
- Department of Physiology and Neurobiology and The Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut
| | - Rana Smalling
- Department of Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Grace Guo
- Department of Pharmacology and Toxicology of School of Pharmacy, Rutgers University, Piscataway, New Jersey
| | - Stefano Fiorucci
- Dipartimento di Scienze Chirurgiche e Biomediche, University of Perugia, Perugia, Italy
| | - Steven H Zeisel
- Nutrition Research Institute, Department of Nutrition, University of North Carolina at Chapel Hill, North Carolina
| | - Li Wang
- Department of Physiology and Neurobiology and The Institute for Systems Genomics, University of Connecticut, Storrs, Connecticut; Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut; Department of Internal Medicine, Section of Digestive Diseases, Yale University, New Haven, Connecticut.
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