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Li T, Chiang JYL. Bile Acid Signaling in Metabolic and Inflammatory Diseases and Drug Development. Pharmacol Rev 2024; 76:1221-1253. [PMID: 38977324 PMCID: PMC11549937 DOI: 10.1124/pharmrev.124.000978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 06/26/2024] [Accepted: 06/28/2024] [Indexed: 07/10/2024] Open
Abstract
Bile acids are the end products of cholesterol catabolism. Hepatic bile acid synthesis accounts for a major fraction of daily cholesterol turnover in humans. Biliary secretion of bile acids generates bile flow and facilitates biliary secretion of lipids, endogenous metabolites, and xenobiotics. In intestine, bile acids facilitate the digestion and absorption of dietary lipids and fat-soluble vitamins. Through activation of nuclear receptors and G protein-coupled receptors and interaction with gut microbiome, bile acids critically regulate host metabolism and innate and adaptive immunity and are involved in the pathogenesis of cholestasis, metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, type-2 diabetes, and inflammatory bowel diseases. Bile acids and their derivatives have been developed as potential therapeutic agents for treating chronic metabolic and inflammatory liver diseases and gastrointestinal disorders. SIGNIFICANCE STATEMENT: Bile acids facilitate biliary cholesterol solubilization and dietary lipid absorption, regulate host metabolism and immunity, and modulate gut microbiome. Targeting bile acid metabolism and signaling holds promise for treating metabolic and inflammatory diseases.
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Affiliation(s)
- Tiangang Li
- Department of Biochemistry and Physiology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (T.L.); and Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio (J.Y.L.C.)
| | - John Y L Chiang
- Department of Biochemistry and Physiology, Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (T.L.); and Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio (J.Y.L.C.)
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Calton CM, Carothers K, Ramamurthy S, Jagadish N, Phanindra B, Garcia A, Viswanathan VK, Halpern MD. Clostridium scindens exacerbates experimental necrotizing enterocolitis via upregulation of the apical sodium-dependent bile acid transporter. Am J Physiol Gastrointest Liver Physiol 2024; 326:G25-G37. [PMID: 37933481 PMCID: PMC11208032 DOI: 10.1152/ajpgi.00102.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 10/19/2023] [Accepted: 11/01/2023] [Indexed: 11/08/2023]
Abstract
Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in premature infants. Evidence indicates that bile acid homeostasis is disrupted during NEC: ileal bile acid levels are elevated in animals with experimental NEC, as is expression of the apical sodium-dependent bile acid transporter (Asbt). In addition, bile acids, which are synthesized in the liver, are extensively modified by the gut microbiome, including via the conversion of primary bile acids to more cytotoxic secondary forms. We hypothesized that the addition of bile acid-modifying bacteria would increase susceptibility to NEC in a neonatal rat model of the disease. The secondary bile acid-producing species Clostridium scindens exacerbated both incidence and severity of NEC. C. scindens upregulated the bile acid transporter Asbt and increased levels of intraenterocyte bile acids. Treatment with C. scindens also altered bile acid profiles and increased hydrophobicity of the ileal intracellular bile acid pool. The ability of C. scindens to enhance NEC requires bile acids, as pharmacological sequestration of ileal bile acids protects animals from developing disease. These findings indicate that bile acid-modifying bacteria can contribute to NEC pathology and provide additional evidence for the role of bile acids in the pathophysiology of experimental NEC.NEW & NOTEWORTHY Necrotizing enterocolitis (NEC), a life-threatening gastrointestinal emergency in premature infants, is characterized by dysregulation of bile acid homeostasis. We demonstrate that administering the secondary bile acid-producing bacterium Clostridium scindens enhances NEC in a neonatal rat model of the disease. C. scindens-enhanced NEC is dependent on bile acids and driven by upregulation of the ileal bile acid transporter Asbt. This is the first report of bile acid-modifying bacteria exacerbating experimental NEC pathology.
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Affiliation(s)
- Christine M Calton
- Department of Pediatrics and Steele Children's Research Center, University of Arizona, Tucson, Arizona, United States
| | - Katelyn Carothers
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, United States
| | - Shylaja Ramamurthy
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, United States
| | - Neha Jagadish
- Department of Pediatrics and Steele Children's Research Center, University of Arizona, Tucson, Arizona, United States
| | - Bhumika Phanindra
- Department of Pediatrics and Steele Children's Research Center, University of Arizona, Tucson, Arizona, United States
| | - Anett Garcia
- Department of Pediatrics and Steele Children's Research Center, University of Arizona, Tucson, Arizona, United States
| | - V K Viswanathan
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, United States
| | - Melissa D Halpern
- Department of Pediatrics and Steele Children's Research Center, University of Arizona, Tucson, Arizona, United States
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Lin X, Zhu X, Xin Y, Zhang P, Xiao Y, He T, Guo H. Intermittent Fasting Alleviates Non-Alcoholic Steatohepatitis by Regulating Bile Acid Metabolism and Promoting Fecal Bile Acid Excretion in High-Fat and High-Cholesterol Diet Fed Mice. Mol Nutr Food Res 2023; 67:e2200595. [PMID: 37148502 DOI: 10.1002/mnfr.202200595] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 02/15/2023] [Indexed: 05/08/2023]
Abstract
SCOPE Intermittent fasting (IF) has a protective role across a wide range of chronic disorders, including obesity, diabetes, and cardiovascular disease, but its protection against non-alcoholic steatohepatitis (NASH) is still lacking. This study seeks to investigate how IF alleviates NASH by regulating gut microbiota and bile acids (BAs) composition. METHODS AND RESULTS Male C57BL/6 mice are fed a high-fat and high-cholesterol (HFHC) diet for 16 weeks to establish a NASH model. Mice then continued HFHC feeding and are treated with or without every other day fasting for 10 weeks. Hepatic pathology is assessed using hematoxylin-eosin staining. Gut microbiota of the cecum are profiled using 16S rDNA gene sequencing and the levels of BAs in serum, colon contents, and feces are measured using ultra-performance liquid chromatography-tandem mass spectrometry. Results indicate that IF significantly decreases murine body weight, insulin resistance, hepatic steatosis, ballooning, and lobular inflammation. IF reshapes the gut microbiota, reduces the accumulation of serum BAs, and increases total colonic and fecal BAs. Moreover, IF increases the expression of cholesterol 7α-hydroxylase 1 in liver, but decreases the expressions of both farnesoid-X-receptor and fibroblast growth factor 15 in the ileum. CONCLUSION IF alleviates NASH by regulating bile acid metabolism and promoting fecal bile acid excretion.
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Affiliation(s)
- Xiaozhuan Lin
- Department of Nutrition, School of Public Health, Guangdong Medical University, Zhanjiang, 524023, China
| | - Xuan Zhu
- Department of Nutrition, School of Public Health, Guangdong Medical University, Zhanjiang, 524023, China
| | - Yan Xin
- Department of Nutrition, School of Public Health, Guangdong Medical University, Zhanjiang, 524023, China
| | - Peiwen Zhang
- Department of Nutrition, School of Public Health, Guangdong Medical University, Zhanjiang, 524023, China
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China
| | - Yunjun Xiao
- The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, 518107, China
| | - Taiping He
- Department of Nutrition, School of Public Health, Guangdong Medical University, Zhanjiang, 524023, China
| | - Honghui Guo
- Department of Nutrition, School of Public Health, Guangdong Medical University, Zhanjiang, 524023, China
- Dongguan Key Laboratory of Environmental Medicine, School of Public Health, Guangdong Medical University, Dongguan, 523808, China
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Zhou S, You H, Qiu S, Yu D, Bai Y, He J, Cao H, Che Q, Guo J, Su Z. A new perspective on NAFLD: Focusing on the crosstalk between peroxisome proliferator-activated receptor alpha (PPARα) and farnesoid X receptor (FXR). Biomed Pharmacother 2022; 154:113577. [PMID: 35988420 DOI: 10.1016/j.biopha.2022.113577] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 08/10/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is primarily caused by abnormal lipid metabolism and the accumulation of triglycerides in the liver. NAFLD is also associated with hepatic steatosis and nutritional and energy imbalances and is a chronic liver disease associated with a number of factors. Nuclear receptors play a key role in balancing energy and nutrient metabolism, and the peroxisome proliferator-activated receptor alpha (PPARα) and farnesoid X receptor (FXR) regulate lipid metabolism genes, controlling hepatocyte lipid utilization and regulating bile acid (BA) synthesis and transport. They play an important role in lipid metabolism and BA homeostasis. At present, PPARα and FXR are the most promising targets for the treatment of NAFLD among nuclear receptors. This review focuses on the crosstalk mechanisms and transcriptional regulation of PPARα and FXR in the pathogenesis of NAFLD and summarizes PPARα and FXR drugs in clinical trials, laying a theoretical foundation for the targeted treatment of NAFLD and the development of novel therapeutic strategies.
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Affiliation(s)
- Shipeng Zhou
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou 510006, China; Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Huimin You
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou 510006, China; Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Shuting Qiu
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou 510006, China; Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Dawei Yu
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou 510006, China; Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Yan Bai
- School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510310, China
| | - Jincan He
- School of Public Health, Guangdong Pharmaceutical University, Guangzhou 510310, China
| | - Hua Cao
- School of Chemistry and Chemical Engineering, Guangdong Pharmaceutical University, Zhongshan 528458, China
| | - Qishi Che
- Guangzhou Rainhome Pharm & Tech Co., Ltd, Science City, Guangzhou 510663, China
| | - Jiao Guo
- Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China.
| | - Zhengquan Su
- Guangdong Engineering Research Center of Natural Products and New Drugs, Guangdong Provincial University Engineering Technology Research Center of Natural Products and Drugs, Guangdong Pharmaceutical University, Guangzhou 510006, China; Guangdong Metabolic Disease Research Center of Integrated Chinese and Western Medicine, Key Laboratory of Glucolipid Metabolic Disorder, Ministry of Education of China, Guangdong TCM Key Laboratory for Metabolic Diseases, Guangdong Pharmaceutical University, Guangzhou 510006, China.
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Fat Malabsorption and Ursodeoxycholic Acid Treatment in Children With Reduced Organic Solute Transporter-α (SLC51A) Expression. JPGN REPORTS 2022; 3. [PMID: 36148443 PMCID: PMC9491403 DOI: 10.1097/pg9.0000000000000229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Choudhuri S, Klaassen CD. Molecular Regulation of Bile Acid Homeostasis. Drug Metab Dispos 2022; 50:425-455. [PMID: 34686523 DOI: 10.1124/dmd.121.000643] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/20/2021] [Indexed: 11/22/2022] Open
Abstract
Bile acids have been known for decades to aid in the digestion and absorption of dietary fats and fat-soluble vitamins in the intestine. The development of gene knockout mice models and transgenic humanized mouse models have helped us understand other functions of bile acids, such as their role in modulating fat, glucose, and energy metabolism, and in the molecular regulation of the synthesis, transport, and homeostasis of bile acids. The G-protein coupled receptor TGR5 regulates the bile acid induced alterations of intermediary metabolism, whereas the nuclear receptor FXR regulates bile acid synthesis and homeostasis. However, this review indicates that unidentified factors in addition to FXR must exist to aid in the regulation of bile acid synthesis and homeostasis. SIGNIFICANCE STATEMENT: This review captures the present understanding of bile acid synthesis, the role of bile acid transporters in the enterohepatic circulation of bile acids, the role of the nuclear receptor FXR on the regulation of bile acid synthesis and bile acid transporters, and the importance of bile acids in activating GPCR signaling via TGR5 to modify intermediary metabolism. This information is useful for developing drugs for the treatment of various hepatic and intestinal diseases, as well as the metabolic syndrome.
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Affiliation(s)
- Supratim Choudhuri
- Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, Maryland (S.C.) and Department of Pharmacology, Toxicology, and Therapeutics, School of Medicine, University of Kansas, Kansas City, Kansas (C.D.K.)
| | - Curtis D Klaassen
- Office of Food Additive Safety, Center for Food Safety and Applied Nutrition, U.S. Food and Drug Administration, College Park, Maryland (S.C.) and Department of Pharmacology, Toxicology, and Therapeutics, School of Medicine, University of Kansas, Kansas City, Kansas (C.D.K.)
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Shulpekova Y, Shirokova E, Zharkova M, Tkachenko P, Tikhonov I, Stepanov A, Sinitsyna A, Izotov A, Butkova T, Shulpekova N, Nechaev V, Damulin I, Okhlobystin A, Ivashkin V. A Recent Ten-Year Perspective: Bile Acid Metabolism and Signaling. Molecules 2022; 27:molecules27061983. [PMID: 35335345 PMCID: PMC8953976 DOI: 10.3390/molecules27061983] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 11/22/2022] Open
Abstract
Bile acids are important physiological agents required for the absorption, distribution, metabolism, and excretion of nutrients. In addition, bile acids act as sensors of intestinal contents, which are determined by the change in the spectrum of bile acids during microbial transformation, as well as by gradual intestinal absorption. Entering the liver through the portal vein, bile acids regulate the activity of nuclear receptors, modify metabolic processes and the rate of formation of new bile acids from cholesterol, and also, in all likelihood, can significantly affect the detoxification of xenobiotics. Bile acids not absorbed by the liver can interact with a variety of cellular recipes in extrahepatic tissues. This provides review information on the synthesis of bile acids in various parts of the digestive tract, its regulation, and the physiological role of bile acids. Moreover, the present study describes the involvement of bile acids in micelle formation, the mechanism of intestinal absorption, and the influence of the intestinal microbiota on this process.
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Affiliation(s)
- Yulia Shulpekova
- Chair of Internal Diseases Propedeutics, Gastroenterology and Hepatology, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia; (Y.S.); (E.S.); (P.T.); (I.T.); (V.N.); (A.O.); (V.I.)
| | - Elena Shirokova
- Chair of Internal Diseases Propedeutics, Gastroenterology and Hepatology, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia; (Y.S.); (E.S.); (P.T.); (I.T.); (V.N.); (A.O.); (V.I.)
| | - Maria Zharkova
- Department of Hepatology University Clinical Hospital No.2, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia;
| | - Pyotr Tkachenko
- Chair of Internal Diseases Propedeutics, Gastroenterology and Hepatology, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia; (Y.S.); (E.S.); (P.T.); (I.T.); (V.N.); (A.O.); (V.I.)
| | - Igor Tikhonov
- Chair of Internal Diseases Propedeutics, Gastroenterology and Hepatology, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia; (Y.S.); (E.S.); (P.T.); (I.T.); (V.N.); (A.O.); (V.I.)
| | - Alexander Stepanov
- Biobanking Group, Branch of Institute of Biomedical Chemistry “Scientific and Education Center”, 109028 Moscow, Russia; (A.S.); (A.S.); (A.I.); (T.B.)
| | - Alexandra Sinitsyna
- Biobanking Group, Branch of Institute of Biomedical Chemistry “Scientific and Education Center”, 109028 Moscow, Russia; (A.S.); (A.S.); (A.I.); (T.B.)
- Correspondence: ; Tel.: +7-499-764-98-78
| | - Alexander Izotov
- Biobanking Group, Branch of Institute of Biomedical Chemistry “Scientific and Education Center”, 109028 Moscow, Russia; (A.S.); (A.S.); (A.I.); (T.B.)
| | - Tatyana Butkova
- Biobanking Group, Branch of Institute of Biomedical Chemistry “Scientific and Education Center”, 109028 Moscow, Russia; (A.S.); (A.S.); (A.I.); (T.B.)
| | | | - Vladimir Nechaev
- Chair of Internal Diseases Propedeutics, Gastroenterology and Hepatology, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia; (Y.S.); (E.S.); (P.T.); (I.T.); (V.N.); (A.O.); (V.I.)
| | - Igor Damulin
- Branch of the V. Serbsky National Medical Research Centre for Psychiatry and Narcology, 127994 Moscow, Russia;
| | - Alexey Okhlobystin
- Chair of Internal Diseases Propedeutics, Gastroenterology and Hepatology, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia; (Y.S.); (E.S.); (P.T.); (I.T.); (V.N.); (A.O.); (V.I.)
| | - Vladimir Ivashkin
- Chair of Internal Diseases Propedeutics, Gastroenterology and Hepatology, Sechenov First Moscow State Medical University (Sechenov University), 119048 Moscow, Russia; (Y.S.); (E.S.); (P.T.); (I.T.); (V.N.); (A.O.); (V.I.)
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van de Wiel SM, Porteiro B, Belt SC, Vogels EW, Bolt I, Vermeulen JL, de Waart DR, Verheij J, Muncan V, Oude Elferink RP, van de Graaf SF. Differential and organ-specific functions of organic solute transporter alpha and beta in experimental cholestasis. JHEP Rep 2022; 4:100463. [PMID: 35462858 PMCID: PMC9019253 DOI: 10.1016/j.jhepr.2022.100463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/15/2022] [Accepted: 02/17/2022] [Indexed: 02/07/2023] Open
Abstract
Background & Aims Organic solute transporter (OST) subunits OSTα and OSTβ facilitate bile acid efflux from the enterocyte into the portal circulation. Patients with deficiency of OSTα or OSTβ display considerable variation in the level of bile acid malabsorption, chronic diarrhea, and signs of cholestasis. Herein, we generated and characterized a mouse model of OSTβ deficiency. Methods Ostβ-/- mice were generated using CRISR/Cas9 and compared to wild-type and Ostα-/- mice. OSTβ was re-expressed in livers of Ostβ-/- mice using adeno-associated virus serotype 8 vectors. Cholestasis was induced in both models by bile duct ligation (BDL) or 3.5-diethoxycarbonyl-1.4-dihydrocollidine (DDC) feeding. Results Similar to Ostα-/- mice, Ostβ-/- mice exhibited elongated small intestines with blunted villi and increased crypt depth. Increased expression levels of ileal Fgf15, and decreased Asbt expression in Ostβ-/- mice indicate the accumulation of bile acids in the enterocyte. In contrast to Ostα-/- mice, induction of cholestasis in Ostβ-/- mice by BDL or DDC diet led to lower survival rates and severe body weight loss, but an improved liver phenotype. Restoration of hepatic Ostβ expression via adeno-associated virus-mediated overexpression did not rescue the phenotype of Ostβ-/- mice. Conclusions OSTβ is pivotal for bile acid transport in the ileum and its deficiency leads to an intestinal phenotype similar to Ostα-/- mice, but it exerts distinct effects on survival and the liver phenotype, independent of its expression in the liver. Our findings provide insights into the variable clinical presentation of patients with OSTα and OSTβ deficiencies. Lay summary Organic solute transporter (OST) subunits OSTα and OSTβ together facilitate the efflux of conjugated bile acids into the portal circulation. Ostα knockout mice have longer and thicker small intestines and are largely protected against experimental cholestatic liver injury. Herein, we generated and characterized Ostβ knockout mice for the first time. Ostα and Ostβ knockout mice shared a similar phenotype under normal conditions. However, in cholestasis, Ostβ knockout mice had a worsened overall phenotype which indicates a separate and specific role of OSTβ, possibly as an interacting partner of other intestinal proteins. This manuscript describes the first mouse model of OSTβ deficiency. Ostβ-/- mice are viable and fertile, but show increased length and weight of the small intestine, blunted villi and deeper crypts. Ostβ deficiency leads to an altered microbiome compared to both wild-type and Ostα-/- mice. Cholestasis led to lower survival and worse body weight loss, but an improved liver phenotype, in Ostβ-/- mice compared to Ostα-/- mice.
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Affiliation(s)
- Sandra M.W. van de Wiel
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
| | - Begoña Porteiro
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
- CIMUS, Universidade de Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, 15782, Spain
| | - Saskia C. Belt
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
| | - Esther W.M. Vogels
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
| | - Isabelle Bolt
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
| | - Jacqueline L.M. Vermeulen
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
| | - D. Rudi de Waart
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
| | - Joanne Verheij
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
- Department of Pathology, Amsterdam UMC, University of Amsterdam, the Netherlands
| | - Vanesa Muncan
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
- Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, the Netherlands
| | - Ronald P.J. Oude Elferink
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
- Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, the Netherlands
| | - Stan F.J. van de Graaf
- Tytgat Institute for Liver and Intestinal Research, Amsterdam UMC, University of Amsterdam, the Netherlands
- Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, the Netherlands
- Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, the Netherlands
- Corresponding author. Address: Meibergdreef 69-71, 1105 BK Amsterdam, the Netherlands; Tel.: 020-5668832, fax: 020-5669190
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Secondary (iso)BAs cooperate with endogenous ligands to activate FXR under physiological and pathological conditions. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166153. [PMID: 33895309 PMCID: PMC8177068 DOI: 10.1016/j.bbadis.2021.166153] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/24/2021] [Accepted: 04/19/2021] [Indexed: 12/30/2022]
Abstract
IsoBAs, stereoisomers of primary and secondary BAs, are found in feces and plasma of human individuals. BA signaling via the nuclear receptor FXR is crucial for regulation of hepatic and intestinal physiology/pathophysiology. AIM Investigate the ability of BA-stereoisomers to bind and modulate FXR under physiological/pathological conditions. METHODS Expression-profiling, luciferase-assays, fluorescence-based coactivator-association assays, administration of (iso)-BAs to WT and cholestatic mice. RESULTS Compared to CDCA/isoCDCA, administration of DCA/isoDCA, UDCA/isoUDCA only slightly increased mRNA expression of FXR target genes; the induction was more evident looking at pre-mRNAs. Notably, almost 50% of isoBAs were metabolized to 3-oxo-BAs within 4 h in cell-based assays, making it difficult to study their actions. FRET-based real-time monitoring of FXR activity revealed that isoCDCA>CDCA stimulated FXR, and isoDCA and isoUDCA allowed fully activated FXR to be re-stimulated by a second dose of GW4064. In vivo co-administration of a single dose of isoBAs followed by GW4064 cooperatively activated FXR, as did feeding of UDCA in a background of endogenous FXR ligands. However, in animals with biliary obstruction and concomitant loss of intestinal BAs, UDCA was unable to increase intestinal Fgf15. In contrast, mice with an impaired enterohepatic circulation of BAs (Asbt-/-, Ostα-/-), administration of UDCA was still able to induce ileal Fgf15 and repress hepatic BA-synthesis, arguing that UDCA is only effective in the presence of endogenous FXR ligands. CONCLUSION Secondary (iso)BAs cooperatively activate FXR in the presence of endogenous BAs, which is important to consider in diseases linked to disturbances in BA enterohepatic cycling.
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Ileal Bile Acid Transporter Inhibitor Improves Hepatic Steatosis by Ameliorating Gut Microbiota Dysbiosis in NAFLD Model Mice. mBio 2021; 12:e0115521. [PMID: 34225483 PMCID: PMC8406289 DOI: 10.1128/mbio.01155-21] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD), characterized by excessive fat deposition in the liver unrelated to alcohol consumption, is highly prevalent worldwide. However, effective therapeutic agents approved for NAFLD treatment are lacking. An ileal bile acid transporter inhibitor (IBATi), which represents a new mode of treatment of chronic idiopathic constipation, leads to increased delivery of bile acids to the colon. We investigated the effect of IBATi against NAFLD through modification of the gut microbiota in mice. IBATi treatment significantly suppressed body weight gain, liver dysfunction, and serum low-density lipoprotein levels and significantly decreased NAFLD activity scores in high-fat diet (HFD) mice. Treatment with IBATi ameliorated the decreased hepatic cholesterol 7-a-monooxygenase (Cyp7a1) and increased ileal fibroblast growth factor 15 (Fgf15) mRNA expression in HFD mice. Further, IBATi treatment changed the α-diversity in the gut microbiota reduced by HFD, which was analyzed in feces using 16S rRNA sequencing. To establish the mechanism underlying improvement in NAFLD induced by IBATi, we recolonized antibiotic solution-treated mice by fecal microbiome transplantation (FMT) using stool from HFD or HFD plus IBATi mice. This is the first report that fecally transplanted gut microbiota from HFD plus IBATi mice prevented hepatic steatosis caused by HFD. In conclusion, IBATi improved hepatic steatosis by ameliorating gut microbiota dysbiosis in NAFLD model mice, suggesting a potential therapeutic agent for NAFLD treatment. IMPORTANCE NAFLD is an increasingly recognized condition that may progress to liver cirrhosis and hepatocellular carcinoma, and community surveys have assessed that the prevalence is 14 to 32% worldwide. The first line of treatment for NAFLD is lifestyle modification to achieve weight reduction, particularly through diet and exercise. However, weight reduction is difficult to achieve and maintain, and pharmacological agents approved for the treatment of NAFLD are lacking. This study investigated the influence of the gut microbiota and the effect of an IBATi on NAFLD using a murine model. Treatment with IBATi significantly improved NAFLD in HFD mice. Further, fecal microbiome transplantation using stool from HFD plus IBATi mice prevented hepatic steatosis caused by HFD. Our study makes a significant contribution to the literature because the study findings suggest a potential treatment strategy for NAFLD patients by ameliorating gut microbiota dysbiosis.
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Kunst RF, Verkade HJ, Oude Elferink RP, van de Graaf SF. Targeting the Four Pillars of Enterohepatic Bile Salt Cycling; Lessons From Genetics and Pharmacology. Hepatology 2021; 73:2577-2585. [PMID: 33222321 PMCID: PMC8252069 DOI: 10.1002/hep.31651] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/29/2020] [Accepted: 11/12/2020] [Indexed: 12/14/2022]
Abstract
Bile salts play a pivotal role in lipid homeostasis, are sensed by specialized receptors, and have been implicated in various disorders affecting the gut or liver. They may play a role either as culprit or as potential panacea. Four very efficient transporters mediate most of the hepatic and intestinal bile salt uptake and efflux, and are each essential for the efficient enterohepatic circulation of bile salts. Starting from the intestinal lumen, conjugated bile salts cross the otherwise impermeable lipid bilayer of (primarily terminal ileal) enterocytes through the apical sodium-dependent bile acid transporter (gene SLC10A2) and leave the enterocyte through the basolateral heteromeric organic solute transporter, which consists of an alpha and beta subunit (encoded by SLC51A and SLC51B). The Na+ -taurocholate cotransporting polypeptide (gene SLC10A1) efficiently clears the portal circulation of bile salts, and the apical bile salt export pump (gene ABCB11) pumps the bile salts out of the hepatocyte into primary bile, against a very steep concentration gradient. Recently, individuals lacking either functional Na+ -taurocholate cotransporting polypeptide or organic solute transporter have been described, completing the quartet of bile acid transport deficiencies, as apical sodium-dependent bile acid transporter and bile salt export pump deficiencies were already known for years. Novel pathophysiological insights have been obtained from knockout mice lacking functional expression of these genes and from pharmacological transporter inhibition in mice or humans. Conclusion: We provide a concise overview of the four main bile salt transport pathways and of their status as possible targets of interventions in cholestatic or metabolic disorders.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 11/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 11/metabolism
- Animals
- Bile Acids and Salts/metabolism
- Biological Transport, Active/drug effects
- Biological Transport, Active/physiology
- Drug Development
- Enterohepatic Circulation/drug effects
- Enterohepatic Circulation/physiology
- Humans
- Membrane Transport Proteins/genetics
- Membrane Transport Proteins/metabolism
- Organic Anion Transporters, Sodium-Dependent/antagonists & inhibitors
- Organic Anion Transporters, Sodium-Dependent/genetics
- Organic Anion Transporters, Sodium-Dependent/metabolism
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Symporters/antagonists & inhibitors
- Symporters/genetics
- Symporters/metabolism
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Affiliation(s)
- Roni F. Kunst
- Tytgat Institute for Liver and Intestinal ResearchAmsterdam UMC, University of AmsterdamAmsterdamthe Netherlands
- Amsterdam Gastroenterology Endocrinology MetabolismAmsterdamthe Netherlands
| | - Henkjan J. Verkade
- Pediatric Gastroenterology/HepatologyDepartment of PediatricsUniversity of GroningenUniversity Medical Center GroningenGroningenthe Netherlands
| | - Ronald P.J. Oude Elferink
- Tytgat Institute for Liver and Intestinal ResearchAmsterdam UMC, University of AmsterdamAmsterdamthe Netherlands
- Amsterdam Gastroenterology Endocrinology MetabolismAmsterdamthe Netherlands
- Department of Gastroenterology and HepatologyAmsterdam UMCUniversity of AmsterdamAmsterdamthe Netherlands
| | - Stan F.J. van de Graaf
- Tytgat Institute for Liver and Intestinal ResearchAmsterdam UMC, University of AmsterdamAmsterdamthe Netherlands
- Amsterdam Gastroenterology Endocrinology MetabolismAmsterdamthe Netherlands
- Department of Gastroenterology and HepatologyAmsterdam UMCUniversity of AmsterdamAmsterdamthe Netherlands
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12
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Ekeuku SO, Pang KL, Chin KY. Palmatine as an Agent Against Metabolic Syndrome and Its Related Complications: A Review. Drug Des Devel Ther 2020; 14:4963-4974. [PMID: 33235437 PMCID: PMC7680161 DOI: 10.2147/dddt.s280520] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 10/29/2020] [Indexed: 12/20/2022] Open
Abstract
Palmatine is a naturally occurring isoquinoline alkaloid with various pharmacological properties. Given its antioxidant and anti-inflammatory properties, palmatine may be able to impede the effects of metabolic syndrome (MetS) and its related diseases triggered by inflammation and oxidative stress. This review summarises the existing literature about the effects of palmatine supplementation on MetS and its complications. The evidence shows that palmatine could protect against MetS, and cardiovascular diseases, osteoporosis and osteoarthritis, which might be associated with MetS. These protective effects are mediated by the antioxidant and anti-inflammatory properties of palmatine. Although preclinical experiments have demonstrated the efficacy of palmatine against MetS and its related diseases, no human clinical trials have been performed to validate these effects. This research gap should be bridged to validate the efficacy and safety of palmatine supplementation in protecting humans against MetS and its related diseases.
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Affiliation(s)
- Sophia Ogechi Ekeuku
- Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia
| | - Kok-Lun Pang
- Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia
| | - Kok-Yong Chin
- Department of Pharmacology, Faculty of Medicine, Universiti Kebangsaan Malaysia, Cheras, Kuala Lumpur, Malaysia
- State Key Laboratory of Oncogenes and Related Genes, Renji-Med X Clinical Stem Cell Research Center, Department of Urology, Ren Ji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
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13
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Xyloglucan affects gut-liver circulating bile acid metabolism to improve liver damage in mice fed with high-fat diet. J Funct Foods 2020. [DOI: 10.1016/j.jff.2019.103651] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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14
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Ticho AL, Malhotra P, Dudeja PK, Gill RK, Alrefai WA. Intestinal Absorption of Bile Acids in Health and Disease. Compr Physiol 2019; 10:21-56. [PMID: 31853951 PMCID: PMC7171925 DOI: 10.1002/cphy.c190007] [Citation(s) in RCA: 140] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The intestinal reclamation of bile acids is crucial for the maintenance of their enterohepatic circulation. The majority of bile acids are actively absorbed via specific transport proteins that are highly expressed in the distal ileum. The uptake of bile acids by intestinal epithelial cells modulates the activation of cytosolic and membrane receptors such as the farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (GPBAR1), which has a profound effect on hepatic synthesis of bile acids as well as glucose and lipid metabolism. Extensive research has focused on delineating the processes of bile acid absorption and determining the contribution of dysregulated ileal signaling in the development of intestinal and hepatic disorders. For example, a decrease in the levels of the bile acid-induced ileal hormone FGF15/19 is implicated in bile acid-induced diarrhea (BAD). Conversely, the increase in bile acid absorption with subsequent overload of bile acids could be involved in the pathophysiology of liver and metabolic disorders such as fatty liver diseases and type 2 diabetes mellitus. This review article will attempt to provide a comprehensive overview of the mechanisms involved in the intestinal handling of bile acids, the pathological implications of disrupted intestinal bile acid homeostasis, and the potential therapeutic targets for the treatment of bile acid-related disorders. Published 2020. Compr Physiol 10:21-56, 2020.
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Affiliation(s)
- Alexander L. Ticho
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Pooja Malhotra
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Pradeep K. Dudeja
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
- jesse Brown VA Medical Center, Chicago, Illinois, USA
| | - Ravinder K. Gill
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Waddah A. Alrefai
- Division of Gastroenterology & Hepatology, Department of Medicine, College of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA
- jesse Brown VA Medical Center, Chicago, Illinois, USA
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15
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Xue Y, Ma C, Hanna I, Pan G. Intestinal Transporter-Associated Drug Absorption and Toxicity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1141:361-405. [DOI: 10.1007/978-981-13-7647-4_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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16
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Somm E, Jornayvaz FR. Fibroblast Growth Factor 15/19: From Basic Functions to Therapeutic Perspectives. Endocr Rev 2018; 39:960-989. [PMID: 30124818 DOI: 10.1210/er.2018-00134] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/10/2018] [Indexed: 12/11/2022]
Abstract
Discovered 20 years ago, fibroblast growth factor (FGF)19, and its mouse ortholog FGF15, were the first members of a new subfamily of FGFs able to act as hormones. During fetal life, FGF15/19 is involved in organogenesis, affecting the development of the ear, eye, heart, and brain. At adulthood, FGF15/19 is mainly produced by the ileum, acting on the liver to repress hepatic bile acid synthesis and promote postprandial nutrient partitioning. In rodents, pharmacologic doses of FGF19 induce the same antiobesity and antidiabetic actions as FGF21, with these metabolic effects being partly mediated by the brain. However, activation of hepatocyte proliferation by FGF19 has long been a challenge to its therapeutic use. Recently, genetic reengineering of the molecule has resolved this issue. Despite a global overlap in expression pattern and function, murine FGF15 and human FGF19 exhibit several differences in terms of regulation, molecular structure, signaling, and biological properties. As most of the knowledge originates from the use of FGF19 in murine models, differences between mice and humans in the biology of FGF15/19 have to be considered for a successful translation from bench to bedside. This review summarizes the basic knowledge concerning FGF15/19 in mice and humans, with a special focus on regulation of production, morphogenic properties, hepatocyte growth, bile acid homeostasis, as well as actions on glucose, lipid, and energy homeostasis. Moreover, implications and therapeutic perspectives concerning FGF19 in human diseases (including obesity, type 2 diabetes, hepatic steatosis, biliary disorders, and cancer) are also discussed.
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Affiliation(s)
- Emmanuel Somm
- Service of Endocrinology, Diabetes, Hypertension, and Nutrition, Geneva University Hospitals, University of Geneva Medical School, Geneva, Switzerland
| | - François R Jornayvaz
- Service of Endocrinology, Diabetes, Hypertension, and Nutrition, Geneva University Hospitals, University of Geneva Medical School, Geneva, Switzerland
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Bustos AY, Font de Valdez G, Fadda S, Taranto MP. New insights into bacterial bile resistance mechanisms: the role of bile salt hydrolase and its impact on human health. Food Res Int 2018; 112:250-262. [DOI: 10.1016/j.foodres.2018.06.035] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/14/2018] [Accepted: 06/18/2018] [Indexed: 01/18/2023]
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18
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Sultan M, Rao A, Elpeleg O, Vaz FM, Abu Libdeh BY, Karpen SJ, Dawson PA. Organic solute transporter-β (SLC51B) deficiency in two brothers with congenital diarrhea and features of cholestasis. Hepatology 2018; 68:590-598. [PMID: 28898457 PMCID: PMC5847420 DOI: 10.1002/hep.29516] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 08/18/2017] [Accepted: 09/06/2017] [Indexed: 12/23/2022]
Abstract
Primary bile acid malabsorption is associated with congenital diarrhea, steatorrhea, and a block in the intestinal return of bile acids in the enterohepatic circulation. Mutations in the ileal apical sodium-dependent bile acid transporter (ASBT; SLC10A2) can cause primary bile acid malabsorption but do not appear to account for most familial cases. Another major transporter involved in the intestinal reclamation of bile acids is the heteromeric organic solute transporter alpha-beta (OSTα-OSTβ; SLC51A-SLC51B), which exports bile acid across the basolateral membrane. Here we report the first patients with OSTβ deficiency, clinically characterized by chronic diarrhea, severe fat soluble vitamin deficiency, and features of cholestatic liver disease including elevated serum gamma-glutamyltransferase activity. Whole exome sequencing revealed a homozygous single nucleotide deletion in codon 27 of SLC51B, resulting in a frameshift and premature termination at codon 50. Functional studies in transfected cells showed that the SLC51B mutation resulted in markedly reduced taurocholic acid uptake activity and reduced expression of the OSTα partner protein. CONCLUSION The findings identify OSTβ deficiency as a cause of congenital chronic diarrhea with features of cholestatic liver disease. These studies underscore OSTα-OSTβ's key role in the enterohepatic circulation of bile acids in humans. (Hepatology 2017).
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Affiliation(s)
- Mutaz Sultan
- Department of Pediatrics, Makassed Hospital, Al-Qud University, Faculty of Medicine. Mount of Olives, P.O. Box 19482, Jerusalem
| | - Anuradha Rao
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Orly Elpeleg
- Monique and Jacques Roboh Department of Genetic Research, Hadassah, Hebrew University Medical Center, Jerusalem, Israel
| | - Frédéric M. Vaz
- Laboratory Genetic Metabolic Diseases, Academic Medical Center, Amsterdam, The Netherlands
| | - Bassam Y Abu Libdeh
- Department of Pediatrics, Makassed Hospital, Al-Qud University, Faculty of Medicine. Mount of Olives, P.O. Box 19482, Jerusalem
| | - Saul J. Karpen
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Paul A. Dawson
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Children’s Healthcare of Atlanta, Atlanta, Georgia
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19
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Li J, Dawson PA. Animal models to study bile acid metabolism. Biochim Biophys Acta Mol Basis Dis 2018; 1865:895-911. [PMID: 29782919 DOI: 10.1016/j.bbadis.2018.05.011] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 05/11/2018] [Accepted: 05/14/2018] [Indexed: 12/19/2022]
Abstract
The use of animal models, particularly genetically modified mice, continues to play a critical role in studying the relationship between bile acid metabolism and human liver disease. Over the past 20 years, these studies have been instrumental in elucidating the major pathways responsible for bile acid biosynthesis and enterohepatic cycling, and the molecular mechanisms regulating those pathways. This work also revealed bile acid differences between species, particularly in the composition, physicochemical properties, and signaling potential of the bile acid pool. These species differences may limit the ability to translate findings regarding bile acid-related disease processes from mice to humans. In this review, we focus primarily on mouse models and also briefly discuss dietary or surgical models commonly used to study the basic mechanisms underlying bile acid metabolism. Important phenotypic species differences in bile acid metabolism between mice and humans are highlighted.
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Affiliation(s)
- Jianing Li
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322, United States
| | - Paul A Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322, United States.
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20
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Ferrebee CB, Li J, Haywood J, Pachura K, Robinson BS, Hinrichs BH, Jones RM, Rao A, Dawson PA. Organic Solute Transporter α-β Protects Ileal Enterocytes From Bile Acid-Induced Injury. Cell Mol Gastroenterol Hepatol 2018; 5:499-522. [PMID: 29930976 PMCID: PMC6009794 DOI: 10.1016/j.jcmgh.2018.01.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 01/05/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND & AIMS Ileal bile acid absorption is mediated by uptake via the apical sodium-dependent bile acid transporter (ASBT), and export via the basolateral heteromeric organic solute transporter α-β (OSTα-OSTβ). In this study, we investigated the cytotoxic effects of enterocyte bile acid stasis in Ostα-/- mice, including the temporal relationship between intestinal injury and initiation of the enterohepatic circulation of bile acids. METHODS Ileal tissue morphometry, histology, markers of cell proliferation, gene, and protein expression were analyzed in male and female wild-type and Ostα-/- mice at postnatal days 5, 10, 15, 20, and 30. Ostα-/-Asbt-/- mice were generated and analyzed. Bile acid activation of intestinal Nrf2-activated pathways was investigated in Drosophila. RESULTS As early as day 5, Ostα-/- mice showed significantly increased ileal weight per length, decreased villus height, and increased epithelial cell proliferation. This correlated with premature expression of the Asbt and induction of bile acid-activated farnesoid X receptor target genes in neonatal Ostα-/- mice. Expression of reduced nicotinamide adenine dinucleotide phosphate oxidase-1 and Nrf2-anti-oxidant responsive genes were increased significantly in neonatal Ostα-/- mice at these postnatal time points. Bile acids also activated Nrf2 in Drosophila enterocytes and enterocyte-specific knockdown of Nrf2 increased sensitivity of flies to bile acid-induced toxicity. Inactivation of the Asbt prevented the changes in ileal morphology and induction of anti-oxidant response genes in Ostα-/- mice. CONCLUSIONS Early in postnatal development, loss of Ostα leads to bile acid accumulation, oxidative stress, and a restitution response in ileum. In addition to its essential role in maintaining bile acid homeostasis, Ostα-Ostβ functions to protect the ileal epithelium against bile acid-induced injury. NCBI Gene Expression Omnibus: GSE99579.
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Key Words
- ARE, anti-oxidant response element
- Asbt, apical sodium-dependent bile acid transporter
- CDCA, chenodeoxycholic acid
- Drosophila
- FGF, fibroblast growth factor
- FXR, farnesoid X receptor
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GFP, green fluorescence protein
- GSH, reduced glutathione
- GSSG, oxidized glutathione
- Ibabp, ileal bile acid binding protein
- Ileum
- NEC, necrotizing enterocolitis
- Neonate
- Nox, reduced nicotinamide adenine dinucleotide phosphate oxidase
- Nrf2, nuclear factor (erythroid-derived 2)-like 2
- Nuclear Factor Erythroid-Derived 2-Like 2
- Ost, organic solute transporter
- PBS, phosphate-buffered saline
- ROS, reactive oxygen species
- Reactive Oxygen Species
- TNF, tumor necrosis factor
- TUNEL, terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end labeling
- WT, wild type
- cRNA, complementary RNA
- mRNA, messenger RNA
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Affiliation(s)
- Courtney B. Ferrebee
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Jianing Li
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | - Jamie Haywood
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Kimberly Pachura
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | | | | | - Rheinallt M. Jones
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | - Anuradha Rao
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
| | - Paul A. Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, Georgia
- Children’s Healthcare of Atlanta, Atlanta, Georgia
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Zhu R, Hou Y, Sun Y, Li T, Fan J, Chen G, Wei J. Pectin Penta-Oligogalacturonide Suppresses Intestinal Bile Acids Absorption and Downregulates the FXR-FGF15 Axis in High-Cholesterol Fed Mice. Lipids 2017; 52:489-498. [PMID: 28474246 DOI: 10.1007/s11745-017-4258-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 04/21/2017] [Indexed: 12/15/2022]
Abstract
Haw pectin penta-oligogalacturonide (HPPS), purified from the hydrolysates of haw pectin, has important role in decreasing hepatic cholesterol accumulation and promoting bile acids (BA) excretion in the feces of mice fed a high-cholesterol diet (HCD). However, the mechanism is not clear. This study aims to investigate the effects of HPPS on BA reabsorption in ileum and biosynthesis in liver of mice. Results showed that HPPS increased fecal BA output by approximately 110%, but decreased ileal BA and the total BA pool size by approximately 47 and 36%, respectively, compared to HCD. Studies of molecular mechanism revealed that HPPS significantly decreased the mRNA and protein levels of farnesoid X receptor (FXR) in the small intestine of mice and inactivated the fibroblast growth factor 15 (FXR-FGF15) axis, which increased the mRNA and protein levels of CYP7A1 by approximately 204 and 104%, respectively, compared to HCD. Interestingly, the mRNA and protein levels of apical sodium-dependent bile acid transporter (ASBT) in the small intestine were approximately 128 and 73% higher in HPPS-fed mice than those in HCD-fed mice, respectively. However, no significant difference was detected for ASBT expression between HCD group and BA sequestrant cholestyramine group. These findings indicate that HPPS can suppress intestinal BA reabsorption and promoting hepatic BA biosynthesis. We speculated that HPPS could be ASBT competitive inhibitor rather than BA sequestrant in inhibiting BA reabsorption in ileum and improving cholesterol metabolism.
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Affiliation(s)
- Rugang Zhu
- Department of Food Science, College of Light Industry, Liaoning University, Liaoning Engineering Research Center for Food Bioprocessing, Shenyang Key Laboratory of Food Bioprocessing and Quality Control, Shenyang, 110036, China.
| | - Yuting Hou
- Department of Food Science, College of Light Industry, Liaoning University, Liaoning Engineering Research Center for Food Bioprocessing, Shenyang Key Laboratory of Food Bioprocessing and Quality Control, Shenyang, 110036, China
| | - Yandi Sun
- Department of Food Science, College of Light Industry, Liaoning University, Liaoning Engineering Research Center for Food Bioprocessing, Shenyang Key Laboratory of Food Bioprocessing and Quality Control, Shenyang, 110036, China
| | - Tuoping Li
- College of Food Science, Shenyang Agriculture University, Shenyang, 110032, China
| | - Jungang Fan
- Forestry Biotechnology and Analysis Test Center, Liaoning Academy of Forestry Sciences, Shenyang, 110032, China
| | - Gang Chen
- Forestry Biotechnology and Analysis Test Center, Liaoning Academy of Forestry Sciences, Shenyang, 110032, China
| | - Junxiu Wei
- Electrical Engineering and Automation, College of Light Industry, Liaoning University, Shenyang, 110032, China
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Abstract
BACKGROUND In addition to their classical role as detergents, bile acids function as signaling molecules to regulate gastrointestinal physiology, carbohydrate and lipid metabolism, and energy expenditure. The pharmacodynamic potential of bile acids is dependent in part on the tight pharmacokinetic control of their concentration and metabolism, properties governed by their hepatic synthesis, enterohepatic cycling, and biotransformation via host and gut microbiota-catalyzed pathways. Key Messages: By altering the normal cycling and compartmentalization of bile acids, changes in hepatobiliary or intestinal transport can affect signaling and lead to the retention of cytotoxic hydrophobic bile acids and cell injury. This review discusses advances in our understanding of the intestinal transporters that maintain the enterohepatic cycling of bile acids, signaling via bile acid-activated nuclear and G protein receptors, and mechanisms of bile acid-induced cell injury. CONCLUSIONS Dysregulated expression of the Asbt and Ostα-Ostβ alters bile acid signaling via the gut-liver farnesoid X receptor-fibroblast growth factor 15/19 axis and may contribute to other bile acid-regulated metabolic and cell injury pathways.
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Affiliation(s)
- Paul A. Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Atlanta, GA 30322, USA
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23
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Schuck-Phan A, Phan T, Dawson PA, Dial EJ, Bell C, Liu Y, Rhoads JM, Lichtenberger LM. Formula Feeding Predisposes Gut to NSAID-Induced Small Intestinal Injury. ACTA ACUST UNITED AC 2016; 6. [PMID: 31565540 DOI: 10.4172/2161-1459.1000222] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Objectives Breast feeding protects infants from many diseases, including necrotizing enterocolitis, peptic ulceration and infectious diarrhea. Conversely, maternal separation stress and Non-Steroidal Anti-Inflammatory Drugs (NSAID's) can induce intestinal injury and bleeding. This study aimed to evaluate in suckling rats if maternal separation/formula feeding leads to increased intestinal sensitivity to indomethacin (indo)-induced intestinal injury and to look at potential mechanisms involved. Methods Nine-day-old rats were dam-fed or separated/trained to formula-feed for 6 days prior to indo administration (5 mg/kg/day) or saline (control) for 3 days. Intestinal bleeding and injury were assessed by measuring luminal and Fecal Hemoglobin (Hob) and jejunal histology. Maturation of the intestine was assessed by measuring luminal bile acids, jejunal sucrase, serum corticosterone, and mRNA expression of ileal Apical Sodium-Dependent Bile Acid Transporter (ASBT). Results At 17 days, formula-fed indo-treated pups had a 2-fold increase in luminal Hb compared to formula-fed control pups and had evidence of morphological injury to the small intestinal mucosa as observed at the light microscopic level, whereas indo had no effect on dam-fed littermates. In addition, formula-fed rats had significant increases in luminal bile acid, sucrase specific activity, serum corticosterone, and expression of ASBT mRNA compared to dam-fed rats. Conclusion Maternal separation stress may cause early intestinal maturational changes induced by corticosteroid release, including increased epithelial exposure to bile acids. These maturational changes may have a sensitizing rather than protective effect against indo-induced injury in the new-born.
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Affiliation(s)
- A Schuck-Phan
- Department of Pediatrics, Division of Pediatric Gastroenterology, University of Texas Health Science Center, Houston, TX, USA
| | - T Phan
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX, USA
| | - P A Dawson
- Department of Pediatrics, Emory University, Atlanta, GA, USA
| | - E J Dial
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX, USA
| | - C Bell
- Department of Pediatrics, Division of Pediatric Gastroenterology, University of Texas Health Science Center, Houston, TX, USA
| | - Y Liu
- Department of Pediatrics, Division of Pediatric Gastroenterology, University of Texas Health Science Center, Houston, TX, USA
| | - J M Rhoads
- Department of Pediatrics, Division of Pediatric Gastroenterology, University of Texas Health Science Center, Houston, TX, USA
| | - L M Lichtenberger
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX, USA
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Pharmacology of bile acid receptors: Evolution of bile acids from simple detergents to complex signaling molecules. Pharmacol Res 2015; 104:9-21. [PMID: 26706784 DOI: 10.1016/j.phrs.2015.12.007] [Citation(s) in RCA: 175] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 12/03/2015] [Indexed: 12/17/2022]
Abstract
For many years, bile acids were thought to only function as detergents which solubilize fats and facilitate the uptake of fat-soluble vitamins in the intestine. Many early observations; however, demonstrated that bile acids regulate more complex processes, such as bile acids synthesis and immune cell function through activation of signal transduction pathways. These studies were the first to suggest that receptors may exist for bile acids. Ultimately, seminal studies by many investigators led to the discovery of several bile acid-activated receptors including the farnesoid X receptor, the vitamin D receptor, the pregnane X receptor, TGR5, α5 β1 integrin, and sphingosine-1-phosphate receptor 2. Several of these receptors are expressed outside of the gastrointestinal system, indicating that bile acids may have diverse functions throughout the body. Characterization of the functions of these receptors over the last two decades has identified many important roles for these receptors in regulation of bile acid synthesis, transport, and detoxification; regulation of glucose utilization; regulation of fatty acid synthesis and oxidation; regulation of immune cell function; regulation of energy expenditure; and regulation of neural processes such as gastric motility. Through these many functions, bile acids regulate many aspects of digestion ranging from uptake of essential vitamins to proper utilization of nutrients. Accordingly, within a short time period, bile acids moved beyond simple detergents and into the realm of complex signaling molecules. Because of the important processes that bile acids regulate through activation of receptors, drugs that target these receptors are under development for the treatment of several diseases, including cholestatic liver disease and metabolic syndrome. In this review, we will describe the various bile acid receptors, the signal transduction pathways activated by these receptors, and briefly discuss the physiological processes that these receptors regulate.
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Ferrebee CB, Dawson PA. Metabolic effects of intestinal absorption and enterohepatic cycling of bile acids. Acta Pharm Sin B 2015; 5:129-34. [PMID: 26579438 PMCID: PMC4629214 DOI: 10.1016/j.apsb.2015.01.001] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 12/30/2014] [Accepted: 01/04/2015] [Indexed: 12/13/2022] Open
Abstract
The classical functions of bile acids include acting as detergents to facilitate the digestion and absorption of nutrients in the gut. In addition, bile acids also act as signaling molecules to regulate glucose homeostasis, lipid metabolism and energy expenditure. The signaling potential of bile acids in compartments such as the systemic circulation is regulated in part by an efficient enterohepatic circulation that functions to conserve and channel the pool of bile acids within the intestinal and hepatobiliary compartments. Changes in hepatobiliary and intestinal bile acid transport can alter the composition, size, and distribution of the bile acid pool. These alterations in turn can have significant effects on bile acid signaling and their downstream metabolic targets. This review discusses recent advances in our understanding of the inter-relationship between the enterohepatic cycling of bile acids and the metabolic consequences of signaling via bile acid-activated receptors, such as farnesoid X nuclear receptor (FXR) and the G-protein-coupled bile acid receptor (TGR5).
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Key Words
- ACCII, acetyl-CoA carboxylase 2
- APO, apolipoproteins
- ASBT, apical sodium-dependent bile acid transporter
- BSEP, bile salt export pump
- Bile acids
- CYP7A1, cholesterol 7α-hydroxylase
- DIO2, deiodinase 2
- Energy homeostasis
- FAS, fatty acid synthase
- FGF, fibroblast growth factor
- FGFR4, fibroblast growth factor receptor 4
- FOXO1, forkhead box protein O1
- FXR, farnesoid X-receptor
- G6Pase, glucose-6-phosphatase
- GLP-1, glucagon-like polypeptide-1
- HNF4α, hepatocyte nuclear factor 4 alpha
- IBABP, ileal bile acid binding protein
- Intestine
- LDL, low density lipoprotein
- Lipid metabolism
- Liver
- NTCP, Na+-taurocholate transporting polypeptide
- OATP, organic anion transporting polypeptide
- OST, organic solute transporter
- PEPCK, phosphoenolpyruvate carboxykinase
- PGC1α, peroxisome proliferator-activated receptor gamma coactivator 1 alpha
- PPAR, peroxisome proliferator-activated receptor
- SHP, small heterodimer partner
- SREBP1c, sterol regulatory element binding protein-1c
- T4, thyroid hormone
- TGR5, G-protein-coupled bile acid receptor
- Transporters
- VLDL, very low density lipoprotein
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Abstract
PURPOSE OF REVIEW This review focuses on the latest understanding of the molecular mechanisms underlying the complex interactions between intestine and liver bile acid signaling, gut microbiota, and their impact on whole-body lipid, glucose and energy metabolism. RECENT FINDINGS Hepatic bile acid synthesis is tightly regulated by the bile acid negative feedback mechanisms. Modulating the enterohepatic bile acid signaling greatly impacts the whole-body metabolic homeostasis. Recently, a positive feedback mechanism through intestine farnesoid X receptor (FXR) antagonism has been proposed to link gut microbiota to the regulation of bile acid composition and pool size. Two studies identified intestine Diet1 and hepatic SHP-2 as novel regulators of CYP7A1 and bile acid synthesis through the gut-liver FXR-fibroblast growth factor 15/19-FGF receptor four signaling axis. New evidence suggests that enhancing bile acid signaling in the distal ileum and colon contributes to the metabolic benefits of bile acid sequestrants and bariatric surgery. SUMMARY Small-molecule ligands that target TGR5 and FXR have shown promise in treating various metabolic and inflammation-related human diseases. New insights into the mechanisms underlying the bariatric surgery and bile acid sequestrant treatment suggest that targeting the enterohepatic circulation to modulate gut-liver bile acid signaling, incretin production and microbiota represents a new strategy to treat obesity and type 2 diabetes.
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Wu Z, Pan D, Guo Y, Zeng X. N-acetylmuramic acid triggers anti-inflammatory capacity in LPS-induced RAW 264.7 cells and mice. J Funct Foods 2015. [DOI: 10.1016/j.jff.2014.12.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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Hammond CL, Wheeler SG, Ballatori N, Hinkle PM. Ostα-/- mice are not protected from western diet-induced weight gain. Physiol Rep 2015; 3:3/1/e12263. [PMID: 25626867 PMCID: PMC4387766 DOI: 10.14814/phy2.12263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Organic solute transporterα‐OSTβ is a bile acid transporter important for bile acid recycling in the enterohepatic circulation. In comparison to wild‐type mice, Ostα−/− mice have a lower bile acid pool and increased fecal lipids and they are relatively resistant to age‐related weight gain and insulin resistance. These studies tested whether Ostα−/− mice are also protected from weight gain, lipid changes, and insulin resistance which are normally observed with a western‐style diet high in both fat and cholesterol (WD). Wild‐type and Ostα−/− mice were fed a WD, a control defined low‐fat diet (LF) or standard laboratory chow (CH). Surprisingly, although the Ostα−/− mice remained lighter on LF and CH diets, they weighed the same as wild‐type mice after 12 weeks on the WD even though bile acid pool levels remained low and fecal lipid excretion remained elevated. Mice of both genotypes excreted relatively less lipid when switched from CH to LF or WD. WD caused slightly greater changes in expression of genes involved in lipid transport in the small intestines of Ostα−/− mice than wild‐type, but the largest differences were between CH and defined diets. After WD feeding, Ostα−/− mice had lower serum cholesterol and hepatic lipids, but Ostα−/− and wild‐type mice had equivalent levels of muscle lipids and similar responses in glucose and insulin tolerance tests. Taken together, the results show that Ostα−/− mice are able to adapt to a western‐style diet despite low bile acid levels. Mice lacking the organic solute transporter (OST) have abnormally low bile acid pools and are resistant to age‐related weight gain. These experiments tested whether Ostα−/− mice are also resistant to western diet‐induced weight gain. Despite low bile acid pools and high fecal lipid excretion, Ostα−/− mice gained weight as rapidly as wild‐type mice.
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Affiliation(s)
- Christine L Hammond
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York, USA
| | - Sadie G Wheeler
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York, USA
| | - Nazzareno Ballatori
- Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York, USA
| | - Patricia M Hinkle
- Department of Pharmacology and Physiology, University of Rochester School of Medicine, Rochester, New York, USA
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Dawson PA. Impact of Inhibiting Ileal Apical versus Basolateral Bile Acid Transport on Cholesterol Metabolism and Atherosclerosis in Mice. Dig Dis 2015; 33:382-7. [PMID: 26045273 PMCID: PMC4465549 DOI: 10.1159/000371691] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Bile acid sequestrants have been used for many years to treat hypercholesterolemia by increasing hepatic conversion of cholesterol to bile acids, thereby inducing hepatic LDL receptor expression and clearance of apoB-containing particles. In order to further understand the underlying molecular mechanisms linking gut-liver signaling and cholesterol homeostasis, mouse models defective in ileal apical membrane bile acid transport (Asbt-null) and ileal basolateral membrane bile acid transport (Ostα-null) were studied under basal and hypercholesterolemic conditions. KEY MESSAGES Hepatic conversion of cholesterol to bile acids is the major pathway for cholesterol catabolism and a major mechanism for cholesterol elimination. Blocking ileal apical membrane bile acid transport (Asbt-null mice) increases fecal bile acid excretion, hepatic Cyp7a1 expression, and the relative proportion of taurocholate in the bile acid pool, but decreases ileal FGF15 expression, bile acid pool size, and hepatic cholesterol content. In contrast, blocking ileal basolateral membrane bile acid transport (Ostα-null mice) increases ileal FGF15 expression, reduces hepatic Cyp7a1 expression, and increases the proportion of tauro-β-muricholic acid in the bile acid pool. In the hypercholesterolemic apoE-null background, plasma cholesterol levels and measurements of atherosclerosis were reduced in Asbt/apoE-null mice, but not in Ostα/apoE-null mice. CONCLUSIONS Blocking the intestinal absorption of bile acids at the apical versus basolateral membrane differentially affects bile acid and cholesterol metabolism, including the development of hypercholesterolemia-associated atherosclerosis. The molecular mechanism likely involves an altered regulation of ileal FGF15 expression.
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Affiliation(s)
- Paul A. Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Emory University School of Medicine, Atlanta, GA 30322
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Dawson PA, Karpen SJ. Intestinal transport and metabolism of bile acids. J Lipid Res 2014; 56:1085-99. [PMID: 25210150 DOI: 10.1194/jlr.r054114] [Citation(s) in RCA: 401] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Indexed: 12/17/2022] Open
Abstract
In addition to their classical roles as detergents to aid in the process of digestion, bile acids have been identified as important signaling molecules that function through various nuclear and G protein-coupled receptors to regulate a myriad of cellular and molecular functions across both metabolic and nonmetabolic pathways. Signaling via these pathways will vary depending on the tissue and the concentration and chemical structure of the bile acid species. Important determinants of the size and composition of the bile acid pool are their efficient enterohepatic recirculation, their host and microbial metabolism, and the homeostatic feedback mechanisms connecting hepatocytes, enterocytes, and the luminal microbiota. This review focuses on the mammalian intestine, discussing the physiology of bile acid transport, the metabolism of bile acids in the gut, and new developments in our understanding of how intestinal metabolism, particularly by the gut microbiota, affects bile acid signaling.
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Affiliation(s)
- Paul A Dawson
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322
| | - Saul J Karpen
- Department of Pediatrics, Division of Gastroenterology, Hepatology, and Nutrition, Emory University, Atlanta, GA 30322
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Baghdasaryan A, Chiba P, Trauner M. Clinical application of transcriptional activators of bile salt transporters. Mol Aspects Med 2014; 37:57-76. [PMID: 24333169 PMCID: PMC4045202 DOI: 10.1016/j.mam.2013.12.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 11/21/2013] [Accepted: 12/01/2013] [Indexed: 02/07/2023]
Abstract
Hepatobiliary bile salt (BS) transporters are critical determinants of BS homeostasis controlling intracellular concentrations of BSs and their enterohepatic circulation. Genetic or acquired dysfunction of specific transport systems causes intrahepatic and systemic retention of potentially cytotoxic BSs, which, in high concentrations, may disturb integrity of cell membranes and subcellular organelles resulting in cell death, inflammation and fibrosis. Transcriptional regulation of canalicular BS efflux through bile salt export pump (BSEP), basolateral elimination through organic solute transporters alpha and beta (OSTα/OSTβ) as well as inhibition of hepatocellular BS uptake through basolateral Na(+)-taurocholate cotransporting polypeptide (NTCP) represent critical steps in protection from hepatocellular BS overload and can be targeted therapeutically. In this article, we review the potential clinical implications of the major BS transporters BSEP, OSTα/OSTβ and NTCP in the pathogenesis of hereditary and acquired cholestatic syndromes, provide an overview on transcriptional control of these transporters by the key regulatory nuclear receptors and discuss the potential therapeutic role of novel transcriptional activators of BS transporters in cholestasis.
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Affiliation(s)
- Anna Baghdasaryan
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria; Laboratory of Experimental and Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine, Medical University of Graz, Austria
| | - Peter Chiba
- Institute of Medical Chemistry, Medical University of Vienna, Austria
| | - Michael Trauner
- Hans Popper Laboratory of Molecular Hepatology, Division of Gastroenterology and Hepatology, Department of Internal Medicine III, Medical University of Vienna, Austria.
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Wheeler SG, Hammond CL, Jornayvaz FR, Samuel VT, Shulman GI, Soroka CJ, Boyer JL, Hinkle PM, Ballatori N. Ostα-/- mice exhibit altered expression of intestinal lipid absorption genes, resistance to age-related weight gain, and modestly improved insulin sensitivity. Am J Physiol Gastrointest Liver Physiol 2014; 306:G425-38. [PMID: 24381083 PMCID: PMC3949021 DOI: 10.1152/ajpgi.00368.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The organic solute transporter OSTα-OSTβ is a key transporter for the efflux of bile acids across the basolateral membrane of ileocytes and the subsequent return of bile acids to the liver. Ostα(-/-) mice exhibit reduced bile acid pools and impaired lipid absorption. In this study, wild-type and Ostα(-/-) mice were characterized at 5 and 12 mo of age. Ostα(-/-) mice were resistant to age-related weight gain, body fat accumulation, and liver and muscle lipid accumulation, and male Ostα(-/-) mice lived slightly longer than wild-type mice. Caloric intake and activity levels were similar for Ostα(-/-) and wild-type male mice. Fecal lipid excretion was increased in Ostα(-/-) mice, indicating that a defect in lipid absorption contributes to decreased fat accumulation. Analysis of genes involved in intestinal lipid absorption revealed changes consistent with decreased dietary lipid absorption in Ostα(-/-) animals. Hepatic expression of cholesterol synthetic genes was upregulated in Ostα(-/-) mice, showing that increased cholesterol synthesis partially compensated for reduced dietary cholesterol absorption. Glucose tolerance was improved in male Ostα(-/-) mice, and insulin sensitivity was improved in male and female Ostα(-/-) mice. Akt phosphorylation was measured in liver and muscle tissue from mice after acute administration of insulin. Insulin responses were significantly larger in male and female Ostα(-/-) than wild-type mice. These findings indicate that loss of OSTα-OSTβ protects against age-related weight gain and insulin resistance.
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Affiliation(s)
- Sadie G. Wheeler
- 1Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York;
| | - Christine L. Hammond
- 1Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York;
| | - François R. Jornayvaz
- 2Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut;
| | - Varman T. Samuel
- 2Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut; ,6Veterans Affairs Medical Center, West Haven, Connecticut; and
| | - Gerald I. Shulman
- 2Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut; ,3Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut; ,4Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut;
| | - Carol J. Soroka
- 5Liver Center, Yale University School of Medicine, New Haven, Connecticut;
| | - James L. Boyer
- 5Liver Center, Yale University School of Medicine, New Haven, Connecticut;
| | - Patricia M. Hinkle
- 7Department of Pharmacology and Physiology, University of Rochester School of Medicine, Rochester, New York
| | - Nazzareno Ballatori
- 1Department of Environmental Medicine, University of Rochester School of Medicine, Rochester, New York;
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Lan T, Haywood J, Dawson PA. Inhibition of ileal apical but not basolateral bile acid transport reduces atherosclerosis in apoE⁻/⁻ mice. Atherosclerosis 2013; 229:374-80. [PMID: 23880190 PMCID: PMC3724224 DOI: 10.1016/j.atherosclerosis.2013.05.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 04/30/2013] [Accepted: 05/17/2013] [Indexed: 12/30/2022]
Abstract
OBJECTIVE Interruption of the enterohepatic circulation of bile acids induces hepatic bile acid synthesis, increases hepatic cholesterol demand, and increases clearance of apoB-containing lipoproteins in plasma. Based on these effects, bile acid sequestrants have been used for many years to treat hypercholesterolemia and the associated atherosclerosis. The objective of this study was to determine the effect of blocking ileal apical versus basolateral membrane bile acid transport on the development of hypercholesterolemia and atherosclerosis in mouse models. METHODS AND RESULTS ApoE(-/-) and Ldlr(-/-) mice deficient in the apical sodium-dependent bile acid transporter (Asbt) or apoE(-/-) mice deficient in the basolateral bile acid transporter (Ostα) were fed an atherogenic diet for 16 weeks. Bile acid metabolism, cholesterol metabolism, gene expression, and development of atherosclerosis were examined. Mice deficient in Asbt exhibited the classic response to interruption of the enterohepatic circulation of bile acids, including significant reductions in hepatic and plasma cholesterol levels, and reduced aortic cholesteryl ester content. Ileal Fibroblast Growth Factor-15 (FGF15) expression was significantly reduced in Asbt(-/-)apoE(-/-) mice and was inversely correlated with expression of hepatic cholesterol 7-hydroxylase (Cyp7a1). Ileal FGF15 expression was directly correlated with plasma cholesterol levels and aortic cholesterol content. In contrast, plasma and hepatic cholesterol levels and atherosclerosis development were not reduced in apoE(-/-) mice deficient in Ostα. CONCLUSIONS Decreases in ileal FGF15, with subsequent increases in hepatic Cyp7a1 expression and bile acid synthesis appear to be necessary for the plasma cholesterol-lowering and atheroprotective effects associated with blocking intestinal bile acid absorption.
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Affiliation(s)
- Tian Lan
- Department of Internal Medicine, Wake Forest School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, USA
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Burrin D, Stoll B, Moore D. Digestive physiology of the pig symposium: intestinal bile acid sensing is linked to key endocrine and metabolic signaling pathways. J Anim Sci 2013; 91:1991-2000. [PMID: 23729782 PMCID: PMC3984497 DOI: 10.2527/jas.2013-6331] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Bile acids have historically been considered to mainly function in cholesterol homeostasis and facilitate fat digestion in the gastrointestinal tract. Recent discoveries show that bile acids also function as signaling molecules that exert diverse endocrine and metabolic actions by activating G protein-coupled bile acid receptor 1 (GPBAR1/G-protein-coupled bile acid receptor 1 or TGR5), a membrane G protein-coupled receptor, and farnesoid X receptor (FXR), a member of the nuclear hormone receptor superfamily. These bile acid sensing receptors are expressed in intestinal epithelial cells, TGR5 in enteroendocrine cells and FXR in enterocytes, which line the mucosa of gut lumen. A dominant effect of intestinal FXR activation by bile acids is secretion of fibroblast growth factor (FGF) 19, a novel enterokine that functions as a central enterohepatic signal to maintain bile acid homeostasis in the liver. Activation of TGR5 on enteroendocrine cells stimulates secretion of glucagon-like peptides (GLP)-1 and -2, which function, respectively, as the major incretin hormone involved in glucose homeostasis and key trophic hormone in intestinal adaptation and growth in response to food ingestion. The biological actions induced by bile acid activation of intestinal FXR and TGR5 have important therapeutic implications for the pathogenesis and treatment of several metabolic diseases, such as cholestasis and diabetes. This review highlights these new developments in the biology of intestinal bile acid sensing and metabolic function and discusses the potential implications for the health and agricultural production of domestic swine.
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Affiliation(s)
- D Burrin
- USDA Children's Nutrition Research Center, Section of Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Houston, TX 77030, USA.
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Karpen SJ. Curiouser and curiouser! J Hepatol 2012; 57:237-8. [PMID: 22634124 DOI: 10.1016/j.jhep.2012.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 05/10/2012] [Indexed: 12/04/2022]
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