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Jefferson B, Ali M, Grant S, Frampton G, Ploof M, Andry S, DeMorrow S, McMillin M. Thrombospondin-1 Exacerbates Acute Liver Failure and Hepatic Encephalopathy Pathology in Mice by Activating Transforming Growth Factor β1. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:347-357. [PMID: 31734229 PMCID: PMC7013272 DOI: 10.1016/j.ajpath.2019.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/28/2019] [Accepted: 10/21/2019] [Indexed: 12/11/2022]
Abstract
Severe hepatic insults can lead to acute liver failure and hepatic encephalopathy (HE). Transforming growth factor β1 (TGFβ1) has been shown to contribute to HE during acute liver failure; however, TGFβ1 must be activated to bind its receptor and generate downstream effects. One protein that can activate TGFβ1 is thrombospondin-1 (TSP-1). Therefore, the aim of this study was to assess TSP-1 during acute liver failure and HE pathogenesis. C57Bl/6 or TSP-1 knockout (TSP-1-/-) mice were injected with azoxymethane (AOM) to induce acute liver failure and HE. Liver damage, neurologic decline, and molecular analyses of TSP-1 and TGFβ1 signaling were performed. AOM-treated mice had increased TSP-1 and TGFβ1 mRNA and protein expression in the liver. TSP-1-/- mice administered AOM had reduced liver injury as assessed by histology and serum transaminase levels compared with C57Bl/6 AOM-treated mice. TSP-1-/- mice treated with AOM had reduced TGFβ1 signaling that was associated with less hepatic cell death as assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining and cleaved caspase 3 expression. TSP-1-/- AOM-treated mice had a reduced rate of neurologic decline, less cerebral edema, and a decrease in microglia activation in comparison with C57Bl/6 mice treated with AOM. Taken together, TSP-1 is an activator of TGFβ1 signaling during AOM-induced acute liver failure and contributes to both liver pathology and HE progression.
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Affiliation(s)
| | - Malaika Ali
- Central Texas Veterans Health Care System, Austin, Texas
| | - Stephanie Grant
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Gabriel Frampton
- Department of Medical Physiology, Texas A&M University Health Science Center, Temple, Texas; Department of Internal Medicine, The University of Texas at Austin Dell Medical School, Austin, Texas
| | - Michaela Ploof
- Central Texas Veterans Health Care System, Austin, Texas
| | - Sarah Andry
- Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Sharon DeMorrow
- Central Texas Veterans Health Care System, Austin, Texas; Department of Medical Physiology, Texas A&M University Health Science Center, Temple, Texas; Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas; Department of Internal Medicine, The University of Texas at Austin Dell Medical School, Austin, Texas
| | - Matthew McMillin
- Central Texas Veterans Health Care System, Austin, Texas; Department of Internal Medicine, The University of Texas at Austin Dell Medical School, Austin, Texas.
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Caspani G, Swann J. Small talk: microbial metabolites involved in the signaling from microbiota to brain. Curr Opin Pharmacol 2019; 48:99-106. [PMID: 31525562 DOI: 10.1016/j.coph.2019.08.001] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/07/2019] [Accepted: 08/14/2019] [Indexed: 12/11/2022]
Abstract
The wealth of biotransformational capabilities encoded in the microbiome expose the host to an array of bioactive xenobiotic products. Several of these metabolites participate in the communication between the gastrointestinal tract and the central nervous system and have potential to modulate central physiological and pathological processes. This biochemical interplay can occur through various direct and indirect mechanisms. These include binding to host receptors in the brain, stimulation of the vagus nerve in the gut, alteration of central neurotransmission, and modulation of neuroinflammation. Here, the potential for short chain fatty acids, bile acids, neurotransmitters and other bioactive products of the microbiome to participate in the gut-brain axis will be reviewed.
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Affiliation(s)
- Giorgia Caspani
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, UK
| | - Jonathan Swann
- Department of Metabolism, Digestion and Reproduction, Faculty of Medicine, Imperial College London, UK.
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53
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Dempsey JL, Little M, Cui JY. Gut microbiome: An intermediary to neurotoxicity. Neurotoxicology 2019; 75:41-69. [PMID: 31454513 DOI: 10.1016/j.neuro.2019.08.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 08/04/2019] [Accepted: 08/16/2019] [Indexed: 12/12/2022]
Abstract
There is growing recognition that the gut microbiome is an important regulator for neurological functions. This review provides a summary on the role of gut microbiota in various neurological disorders including neurotoxicity induced by environmental stressors such as drugs, environmental contaminants, and dietary factors. We propose that the gut microbiome remotely senses and regulates CNS signaling through the following mechanisms: 1) intestinal bacteria-mediated biotransformation of neurotoxicants that alters the neuro-reactivity of the parent compounds; 2) altered production of neuro-reactive microbial metabolites following exposure to certain environmental stressors; 3) bi-directional communication within the gut-brain axis to alter the intestinal barrier integrity; and 4) regulation of mucosal immune function. Distinct microbial metabolites may enter systemic circulation and epigenetically reprogram the expression of host genes in the CNS, regulating neuroinflammation, cell survival, or cell death. We will also review the current tools for the study of the gut-brain axis and provide some suggestions to move this field forward in the future.
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Affiliation(s)
- Joseph L Dempsey
- Department of Environmental and Occupational Health Sciences, University of Washington, United States
| | - Mallory Little
- Department of Environmental and Occupational Health Sciences, University of Washington, United States
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, United States.
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54
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Schmidt A, Joussen S, Hausmann R, Gründer S, Wiemuth D. Bile acids are potent inhibitors of rat P2X2 receptors. Purinergic Signal 2019; 15:213-221. [PMID: 31098843 DOI: 10.1007/s11302-019-09657-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/17/2019] [Indexed: 01/06/2023] Open
Abstract
Extracellular adenosine triphosphate (ATP) regulates a broad variety of physiological functions in a number of tissues partly via ionotropic P2X receptors. Therefore, P2X receptors are promising targets for the development of therapeutically active molecules. Bile acids are cholesterol-derived amphiphilic molecules; their primary function is the facilitation of efficient nutrient fat digestion. However, bile acids have also been shown to serve as signaling molecules and as modulators of different membrane proteins and receptors including ion channels. In addition, some P2X receptors are sensitive to structurally related steroid hormones. In this study, we systematically analyzed whether rat P2X receptors are affected by micromolar concentrations of different bile acids. The taurine-conjugated bile acids TLCA, THDCA, and TCDCA potently inhibited P2X2, whereas other P2X receptors were only mildly affected. Furthermore, stoichiometry and species origin of the P2X receptors affected the modulation by bile acids: in comparison to rat P2X2, the heteromeric P2X2/3 receptor was less potently modulated and the human P2X2 receptor was potentiated by TLCA. In summary, bile acids are a new class of P2X receptor modulators, which might be of physiological relevance.
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Affiliation(s)
- Axel Schmidt
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Sylvia Joussen
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Ralf Hausmann
- Molecular Pharmacology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Dominik Wiemuth
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
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55
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McMillin M, Grant S, Frampton G, Petrescu AD, Williams E, Jefferson B, Thomas A, Brahmaroutu A, DeMorrow S. Elevated circulating TGFβ1 during acute liver failure activates TGFβR2 on cortical neurons and exacerbates neuroinflammation and hepatic encephalopathy in mice. J Neuroinflammation 2019; 16:69. [PMID: 30940161 PMCID: PMC6446280 DOI: 10.1186/s12974-019-1455-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/18/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Acute liver failure resulting from drug-induced liver injury can lead to the development of neurological complications called hepatic encephalopathy (HE). Hepatic transforming growth factor beta 1 (TGFβ1) is upregulated due to liver failure in mice and inhibiting circulating TGFβ reduced HE progression. However, the specific contributions of TGFβ1 on brain cell populations and neuroinflammation during HE are not known. Therefore, the aim of this study was to characterize hepatic and brain TGFβ1 signaling during acute liver failure and its contribution to HE progression using a combination of pharmacological and genetic approaches. METHODS C57Bl/6 or neuron-specific transforming growth factor beta receptor 2 (TGFβR2) null mice (TGFβR2ΔNeu) were treated with azoxymethane (AOM) to induce acute liver failure and HE. The activity of circulating TGFβ1 was inhibited in C57Bl/6 mice via injection of a neutralizing antibody against TGFβ1 (anti-TGFβ1) prior to AOM injection. In all mouse treatment groups, liver damage, neuroinflammation, and neurological deficits were assessed. Inflammatory signaling between neurons and microglia were investigated in in vitro studies through the use of pharmacological inhibitors of TGFβ1 signaling in HT-22 and EOC-20 cells. RESULTS TGFβ1 was expressed and upregulated in the liver following AOM injection. Pharmacological inhibition of TGFβ1 after AOM injection attenuated neurological decline, microglia activation, and neuroinflammation with no significant changes in liver damage. TGFβR2ΔNeu mice administered AOM showed no effect on liver pathology but significantly reduced neurological decline compared to control mice. Microglia activation and neuroinflammation were attenuated in mice with pharmacological inhibition of TGFβ1 or in TGFβR2ΔNeu mice. TGFβ1 increased chemokine ligand 2 (CCL2) and decreased C-X3-C motif ligand 1 (CX3CL1) expression in HT-22 cells and reduced interleukin-1 beta (IL-1ß) expression, tumor necrosis factor alpha (TNFα) expression, and phagocytosis activity in EOC-20 cells. CONCLUSION Increased circulating TGFβ1 following acute liver failure results in activation of neuronal TGFβR2 signaling, driving neuroinflammation and neurological decline during AOM-induced HE.
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Affiliation(s)
- Matthew McMillin
- Central Texas Veterans Health Care System, Temple, TX, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA.,Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Stephanie Grant
- Central Texas Veterans Health Care System, Temple, TX, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA.,Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Gabriel Frampton
- Central Texas Veterans Health Care System, Temple, TX, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA.,Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Anca D Petrescu
- Central Texas Veterans Health Care System, Temple, TX, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA.,Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Elaina Williams
- Central Texas Veterans Health Care System, Temple, TX, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA.,Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA
| | - Brandi Jefferson
- Central Texas Veterans Health Care System, Temple, TX, USA.,Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA
| | - Alison Thomas
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA
| | - Ankita Brahmaroutu
- Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA
| | - Sharon DeMorrow
- Central Texas Veterans Health Care System, Temple, TX, USA. .,Department of Medical Physiology, College of Medicine, Texas A&M University Health Science Center, Temple, TX, USA. .,Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, TX, USA. .,Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Austin, TX, USA.
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Abstract
Hepatic encephalopathy describes the array of neurological complications that arise due to liver insufficiency and/or portal-systemic shunt. The pathogenesis of hepatic encephalopathy shares a longstanding association with hyperammonemia and inflammation. Recently, aberrant bile acid signaling has been implicated in the development of key features of hepatic encephalopathy due to acute liver failure including neuronal dysfunction, neuroinflammation and blood-brain barrier permeability. This review summarizes the findings of recent studies demonstrating a role for bile acids in hepatic encephalopathy and speculates on the possible downstream consequences of bile acid signaling.
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Key Words
- ASBT, Apical Sodium-Dependent Bile Acid Transporter
- CCL2, Chemokine Ligand 2
- CCR2, Chemokine Receptor 2
- Cyp46A1, Cytochrome p450 46A1
- FXR, Farnesoid X Receptor
- GR, Glucocorticoid Receptor
- NTCP, Sodium Taurocholate Cotransporting Polypeptide
- PXR, Pregnane X Receptor
- S1P2R, Sphingosine 1 Phosphate Receptor 2
- TGR5, Takeda G-Protein Receptor 5
- Takeda G-protein coupled receptor 5 (TGR5)
- VDR, Vitamin D Receptor
- blood–brain barrier
- farnesoid X receptor
- neuroinflammation
- sphingosine-1-phosphate receptor 2
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57
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Xie G, Wang X, Jiang R, Zhao A, Yan J, Zheng X, Huang F, Liu X, Panee J, Rajani C, Yao C, Yu H, Jia W, Sun B, Liu P, Jia W. Dysregulated bile acid signaling contributes to the neurological impairment in murine models of acute and chronic liver failure. EBioMedicine 2018; 37:294-306. [PMID: 30344125 PMCID: PMC6284422 DOI: 10.1016/j.ebiom.2018.10.030] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/04/2018] [Accepted: 10/10/2018] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Hepatic encephalopathy (HE), a severe neuropsychiatric complication, is associated with increased blood levels of ammonia and bile acids (BAs). We sought to determine (1) whether abnormally increased blood BAs in liver cirrhotic patients with HE is caused by elevation of apical sodium-dependent BA transporter (ASBT)-mediated BA reabsorption; and (2) whether increased BA reabsorption would exacerbate ammonia-induced brain injuries. METHODS We quantitatively measured blood BA and ammonia levels in liver cirrhosis patients with or without HE and healthy controls. We characterized ASBT expression, BA profiles, and ammonia concentrations in a chronic liver disease (CLD) mouse model induced by streptozotocin-high fat diet (STZ-HFD) and an azoxymethane (AOM) - induced acute liver failure (ALF) mouse model. These two mouse models were treated with SC-435 (ASBT inhibitor) and budesonide (ASBT activator), respectively. FINDINGS Blood concentrations of ammonia and conjugated BAs were substantially increased in cirrhotic patients with HE (n = 75) compared to cirrhotic patients without HE (n = 126). Pharmacological inhibition of the enterohepatic BA circulation using a luminal- restricted ASBT inhibitor, SC-435, in mice with AOM-induced ALF and STZ-HFD -induced CLD effectively reduced BA and ammonia concentrations in the blood and brain, and alleviated liver and brain damages. Budesonide treatment induced liver and brain damages in normal mice, and exacerbated these damages in AOM-treated mice. INTERPRETATION ASBT mediated BA reabsorption increases intestinal luminal pH and facilitates conversion of intestinal ammonium to ammonia, leading to abnormally high levels of neurotoxic ammonia and cytotoxic BAs in the blood and brain. Inhibition of intestinal ASBT with SC-435 can effectively remove neurotoxic BAs and ammonia from the bloodstream and thus, mitigate liver and brain injuries resulting from liver failure.
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Affiliation(s)
- Guoxiang Xie
- Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China; University of Hawaii Cancer Center, Honolulu, HI 96813, USA
| | - Xiaoning Wang
- E-institute of Shanghai Municipal Education Committee, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Key Laboratory of Liver and Kidney Diseases (Ministry of Education), Institute of Liver Diseases, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Runqiu Jiang
- University of Hawaii Cancer Center, Honolulu, HI 96813, USA; Liver Transplantation Center of the First Affiliated Hospital, State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Aihua Zhao
- Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Jingyu Yan
- E-institute of Shanghai Municipal Education Committee, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Xiaojiao Zheng
- Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Fengjie Huang
- Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Xinzhu Liu
- E-institute of Shanghai Municipal Education Committee, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China
| | - Jun Panee
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96813, USA
| | - Cynthia Rajani
- University of Hawaii Cancer Center, Honolulu, HI 96813, USA
| | - Chun Yao
- Guangxi University of Chinese Medicine, Nanning, Guangxi 530001, China
| | - Herbert Yu
- University of Hawaii Cancer Center, Honolulu, HI 96813, USA
| | - Weiping Jia
- Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Beicheng Sun
- Liver Transplantation Center of the First Affiliated Hospital, State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Ping Liu
- E-institute of Shanghai Municipal Education Committee, Institute of Interdisciplinary Integrative Medicine Research, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China; Key Laboratory of Liver and Kidney Diseases (Ministry of Education), Institute of Liver Diseases, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
| | - Wei Jia
- Shanghai Key Laboratory of Diabetes Mellitus and Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China; University of Hawaii Cancer Center, Honolulu, HI 96813, USA.
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Al-Khaifi A, Straniero S, Voronova V, Chernikova D, Sokolov V, Kumar C, Angelin B, Rudling M. Asynchronous rhythms of circulating conjugated and unconjugated bile acids in the modulation of human metabolism. J Intern Med 2018; 284:546-559. [PMID: 29964306 DOI: 10.1111/joim.12811] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND AND OBJECTIVES Bile acids (BAs) traversing the enterohepatic circulation (EHC) influence important metabolic pathways. By determining individual serum BAs in relation to markers of metabolic activity, we explored how diurnal variations in their EHC relate to hepatic metabolism in normal humans. METHODS Serum BAs, fibroblast growth factor 19 (FGF19), lipoproteins, glucose/insulin and markers of cholesterol and BA syntheses were monitored for 32 h in 8 healthy males. Studies were conducted at basal state and during initiation of cholestyramine treatment, with and without atorvastatin pretreatment. Time series cross-correlation analysis, Bayesian structural model and Granger causality test were applied. RESULTS Bile acids synthesis dominated daytime, and cholesterol production at night. Conjugated BAs peaked after food intake, with subsequent FGF19 elevations. BA synthesis was reduced following conjugated BA and FGF19 peaks. Cholestyramine reduced conjugated BAs and FGF19, and increased BA and cholesterol production; the latter effects attenuated by atorvastatin. The relative importance of FGF19 vs. conjugated BAs in this feedback inhibition could not be discriminated. Unconjugated BAs displayed one major peak late at night/early morning that was unrelated to FGF19 and BA synthesis, and abolished by cholestyramine. The normal suppression of serum triglycerides, glucose and insulin observed at night was attenuated by cholestyramine. CONCLUSIONS Conjugated and unconjugated BAs have asynchronous rhythms of EHC in humans. Postprandial transintestinal flux of conjugated BAs increases circulating FGF19 levels and suppresses BA synthesis. Unconjugated BAs peak late at night, indicating a non-postprandial diurnal change in human gut microflora, the physiological implications of which warrants further study.
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Affiliation(s)
- A Al-Khaifi
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden.,Department of Biochemistry, College of Medicine, Sultan Qaboos University, Muscat 123, Oman
| | - S Straniero
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden
| | | | | | | | - C Kumar
- Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden.,Translational Sciences, Cardiovascular, Renal and Metabolism, IMED Biotech Unit, AstraZeneca, Gothenburg, Sweden
| | - B Angelin
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden
| | - M Rudling
- Metabolism Unit, Endocrinology, Metabolism and Diabetes, Department of Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.,Department of Medicine, Karolinska Institutet/AstraZeneca Integrated CardioMetabolic Center (KI/AZ ICMC), Novum, Stockholm, Sweden
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McMillin M, Grant S, Frampton G, Petrescu AD, Kain J, Williams E, Haines R, Canady L, DeMorrow S. FXR-Mediated Cortical Cholesterol Accumulation Contributes to the Pathogenesis of Type A Hepatic Encephalopathy. Cell Mol Gastroenterol Hepatol 2018; 6:47-63. [PMID: 29928671 PMCID: PMC6008252 DOI: 10.1016/j.jcmgh.2018.02.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Accepted: 02/26/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND & AIMS Hepatic encephalopathy is a serious neurologic complication of acute and chronic liver diseases. We previously showed that aberrant bile acid signaling contributes to the development of hepatic encephalopathy via farnesoid X receptor (FXR)-mediated mechanisms in neurons. In the brain, a novel alternative bile acid synthesis pathway, catalyzed by cytochrome p450 46A1 (Cyp46A1), is the primary mechanism by which the brain regulates cholesterol homeostasis. The aim of this study was to determine if FXR activation in the brain altered cholesterol homeostasis during hepatic encephalopathy. METHODS Cyp7A1-/- mice or C57Bl/6 mice pretreated with central infusion of FXR vivo morpholino, 2-hydroxypropyl-β-cyclodextrin, or fed a cholestyramine-supplemented diet were injected with azoxymethane (AOM). Cognitive and neuromuscular impairment as well as liver damage and expression of Cyp46A1 were assessed using standard techniques. The subsequent cholesterol content in the frontal cortex was measured using commercially available kits and by Filipin III and Nile Red staining. RESULTS There was an increase in membrane-bound and intracellular cholesterol in the cortex of mice treated with AOM that was associated with decreased Cyp46A1 expression. Strategies to inhibit FXR signaling prevented the down-regulation of Cyp46A1 and the accumulation of cholesterol. Treatment of mice with 2-hydroxypropyl-β-cyclodextrin attenuated the AOM-induced cholesterol accumulation in the brain and the cognitive and neuromuscular deficits without altering the underlying liver pathology. CONCLUSIONS During hepatic encephalopathy, FXR signaling increases brain cholesterol and contributes to neurologic decline. Targeting cholesterol accumulation in the brain may be a possible therapeutic target for the management of hepatic encephalopathy.
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Key Words
- 2-HβC, 2-hypdroxypropyl-β-cyclodextrin
- AOM, azoxymethane
- Acute Liver Failure
- Azoxymethane
- CYP46A1, cytochrome p450 46A1
- CYP7A1, cytochrome p450 7A1
- Cytochrome p450 46A1
- FXR, farnesoid X receptor
- Farnesoid X Receptor
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- PBS, phosphate-buffered saline
- PFA, paraformaldehyde
- RT-PCR, reverse-transcription polymerase chain reaction
- WT, wild-type
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Affiliation(s)
- Matthew McMillin
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Stephanie Grant
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Gabriel Frampton
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Anca D. Petrescu
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Jessica Kain
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Elaina Williams
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Rebecca Haines
- Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Lauren Canady
- Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas
| | - Sharon DeMorrow
- Central Texas Veterans Healthcare System, Temple, Texas,Department of Medical Physiology, Texas A&M College of Medicine, Temple, Texas,Correspondence Address correspondence to: Sharon DeMorrow, PhD, Department of Medical Physiology, Texas A&M Health Science Center, Central Texas Veterans Health Care System, Building 205, 1901 South 1st Street, Temple, Texas 76504. fax: (254) 743-0378.
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60
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Frisch K, Alstrup AKO. On the Evolution of Bile Salts and the Farnesoid X Receptor in Vertebrates. Physiol Biochem Zool 2018; 91:797-813. [DOI: 10.1086/695810] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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61
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Arnold JW, Simpson JB, Roach J, Kwintkiewicz J, Azcarate-Peril MA. Intra-species Genomic and Physiological Variability Impact Stress Resistance in Strains of Probiotic Potential. Front Microbiol 2018; 9:242. [PMID: 29515537 PMCID: PMC5826259 DOI: 10.3389/fmicb.2018.00242] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/31/2018] [Indexed: 12/28/2022] Open
Abstract
Large-scale microbiome studies have established that most of the diversity contained in the gastrointestinal tract is represented at the strain level; however, exhaustive genomic and physiological characterization of human isolates is still lacking. With increased use of probiotics as interventions for gastrointestinal disorders, genomic and functional characterization of novel microorganisms becomes essential. In this study, we explored the impact of strain-level genomic variability on bacterial physiology of two novel human Lactobacillus rhamnosus strains (AMC143 and AMC010) of probiotic potential in relation to stress resistance. The strains showed differences with known probiotic strains (L. rhamnosus GG, Lc705, and HN001) at the genomic level, including nucleotide polymorphisms, mutations in non-coding regulatory regions, and rearrangements of genomic architecture. Transcriptomics analysis revealed that gene expression profiles differed between strains when exposed to simulated gastrointestinal stresses, suggesting the presence of unique regulatory systems in each strain. In vitro physiological assays to test resistance to conditions mimicking the gut environment (acid, alkali, and bile stress) showed that growth of L. rhamnosus AMC143 was inhibited upon exposure to alkaline pH, while AMC010 and control strain LGG were unaffected. AMC143 also showed a significant survival advantage compared to the other strains upon bile exposure. Reverse transcription qPCR targeting the bile salt hydrolase gene (bsh) revealed that AMC143 expressed bsh poorly (a consequence of a deletion in the bsh promoter and truncation of bsh gene in AMC143), while AMC010 had significantly higher expression levels than AMC143 or LGG. Insertional inactivation of the bsh gene in AMC010 suggested that bsh could be detrimental to bacterial survival during bile stress. Together, these findings show that coupling of classical microbiology with functional genomics methods for the characterization of bacterial strains is critical for the development of novel probiotics, as variability between strains can dramatically alter bacterial physiology and functionality.
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Affiliation(s)
- Jason W. Arnold
- Division of Gastroenterology and Hepatology, Department of Medicine, Microbiome Core Facility, Center for Gastrointestinal Biology and Disease, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - Joshua B. Simpson
- Department of Chemistry, College of Arts and Sciences, University of North Carolina, Chapel Hill, NC, United States
| | - Jeffrey Roach
- Research Computing, University of North Carolina, Chapel Hill, NC, United States
| | - Jakub Kwintkiewicz
- Division of Gastroenterology and Hepatology, Department of Medicine, Microbiome Core Facility, Center for Gastrointestinal Biology and Disease, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
| | - M. Andrea Azcarate-Peril
- Division of Gastroenterology and Hepatology, Department of Medicine, Microbiome Core Facility, Center for Gastrointestinal Biology and Disease, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
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62
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Eggink HM, Tambyrajah LL, van den Berg R, Mol IM, van den Heuvel JK, Koehorst M, Groen AK, Boelen A, Kalsbeek A, Romijn JA, Rensen PCN, Kooijman S, Soeters MR. Chronic infusion of taurolithocholate into the brain increases fat oxidation in mice. J Endocrinol 2018; 236:85-97. [PMID: 29233934 DOI: 10.1530/joe-17-0503] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 12/11/2017] [Indexed: 01/11/2023]
Abstract
Bile acids can function in the postprandial state as circulating signaling molecules in the regulation of glucose and lipid metabolism via the transmembrane receptor TGR5 and nuclear receptor FXR. Both receptors are present in the central nervous system, but their function in the brain is unclear. Therefore, we investigated the effects of intracerebroventricular (i.c.v.) administration of taurolithocholate (tLCA), a strong TGR5 agonist, and GW4064, a synthetic FXR agonist, on energy metabolism. We determined the effects of chronic i.c.v. infusion of tLCA, GW4064, or vehicle on energy expenditure, body weight and composition as well as tissue specific fatty acid uptake in mice equipped with osmotic minipumps. We found that i.c.v. administration of tLCA (final concentration in cerebrospinal fluid: 1 μM) increased fat oxidation (tLCA group: 0.083 ± 0.006 vs control group: 0.036 ± 0.023 kcal/h, F = 5.46, P = 0.04) and decreased fat mass (after 9 days of tLCA infusion: 1.35 ± 0.13 vs controls: 1.96 ± 0.23 g, P = 0.03). These changes were associated with enhanced uptake of triglyceride-derived fatty acids by brown adipose tissue and with browning of subcutaneous white adipose tissue. I.c.v. administration of GW4064 (final concentration in cerebrospinal fluid: 10 μM) did not affect energy metabolism, body composition nor bile acid levels, negating a role of FXR in the central nervous system in metabolic control. In conclusion, bile acids such as tLCA may exert metabolic effects on fat metabolism via the brain.
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Affiliation(s)
- Hannah M Eggink
- Department of Endocrinology and MetabolismAcademic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
- Hypothalamic Integration MechanismsNetherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Lauren L Tambyrajah
- Division of EndocrinologyDepartment of Medicine, Leiden University Medical Centre, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical Centre, Leiden, The Netherlands
| | - Rosa van den Berg
- Division of EndocrinologyDepartment of Medicine, Leiden University Medical Centre, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical Centre, Leiden, The Netherlands
| | - Isabel M Mol
- Division of EndocrinologyDepartment of Medicine, Leiden University Medical Centre, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical Centre, Leiden, The Netherlands
| | - Jose K van den Heuvel
- Division of EndocrinologyDepartment of Medicine, Leiden University Medical Centre, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical Centre, Leiden, The Netherlands
| | - Martijn Koehorst
- Department of Pediatrics and Laboratory MedicineUniversity Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Albert K Groen
- Department of Pediatrics and Laboratory MedicineUniversity Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
- Department of Vascular MedicineAmsterdam Diabetes Centre, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Anita Boelen
- Department of Endocrinology and MetabolismAcademic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and MetabolismAcademic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
- Hypothalamic Integration MechanismsNetherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Johannes A Romijn
- Department of MedicineAcademic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Patrick C N Rensen
- Division of EndocrinologyDepartment of Medicine, Leiden University Medical Centre, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical Centre, Leiden, The Netherlands
| | - Sander Kooijman
- Division of EndocrinologyDepartment of Medicine, Leiden University Medical Centre, Leiden, The Netherlands
- Einthoven Laboratory for Experimental Vascular MedicineLeiden University Medical Centre, Leiden, The Netherlands
| | - Maarten R Soeters
- Department of Endocrinology and MetabolismAcademic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
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63
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Petrescu AD, Kain J, Liere V, Heavener T, DeMorrow S. Hypothalamus-Pituitary-Adrenal Dysfunction in Cholestatic Liver Disease. Front Endocrinol (Lausanne) 2018; 9:660. [PMID: 30483216 PMCID: PMC6240761 DOI: 10.3389/fendo.2018.00660] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 10/22/2018] [Indexed: 12/11/2022] Open
Abstract
The Hypothalamic-Pituitary-Adrenal (HPA) axis has an important role in maintaining the physiological homeostasis in relation to external and internal stimuli. The HPA axis dysfunctions were extensively studied in neuroendocrine disorders such as depression and chronic fatigue syndrome but less so in hepatic cholestasis, cirrhosis or other liver diseases. The HPA axis controls many functions of the liver through neuroendocrine forward signaling pathways as well as negative feedback mechanisms, in health and disease. This review describes cell and molecular mechanisms of liver and HPA axis physiology and pathology. Evidence is presented from clinical and experimental model studies, demonstrating that dysfunctions of HPA axis are correlated with liver cholestatic disorders. The functional interactions of HPA axis with the liver and immune system in cases of bacterial and viral infections are also discussed. Proinflammatory cytokines stimulate glucocorticoid (GC) release by adrenals but they also inhibit bile acid (BA) efflux from liver. Chronic hepatic inflammation leads to cholestasis and impaired GC metabolism in the liver, so that HPA axis becomes depressed. Recently discovered interactions of GC with self-oscillating transcription factors that generate circadian rhythms of gene expression in brain and liver, in the context of GC replacement therapies, are also outlined.
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Affiliation(s)
- Anca D. Petrescu
- Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, United States
| | - Jessica Kain
- Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, United States
| | - Victoria Liere
- Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, United States
| | - Trace Heavener
- Department of Internal Medicine, Texas A&M Health Science Center College of Medicine, Temple, TX, United States
| | - Sharon DeMorrow
- Department of Medical Physiology, Texas A&M Health Science Center College of Medicine, Temple, TX, United States
- Department of Internal Medicine, Texas A&M Health Science Center College of Medicine, Temple, TX, United States
- Department of Research Services, Central Texas Veterans Health Care System, Temple, TX, United States
- *Correspondence: Sharon DeMorrow
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64
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Mertens KL, Kalsbeek A, Soeters MR, Eggink HM. Bile Acid Signaling Pathways from the Enterohepatic Circulation to the Central Nervous System. Front Neurosci 2017; 11:617. [PMID: 29163019 PMCID: PMC5681992 DOI: 10.3389/fnins.2017.00617] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 10/23/2017] [Indexed: 12/14/2022] Open
Abstract
Bile acids are best known as detergents involved in the digestion of lipids. In addition, new data in the last decade have shown that bile acids also function as gut hormones capable of influencing metabolic processes via receptors such as FXR (farnesoid X receptor) and TGR5 (Takeda G protein-coupled receptor 5). These effects of bile acids are not restricted to the gastrointestinal tract, but can affect different tissues throughout the organism. It is still unclear whether these effects also involve signaling of bile acids to the central nervous system (CNS). Bile acid signaling to the CNS encompasses both direct and indirect pathways. Bile acids can act directly in the brain via central FXR and TGR5 signaling. In addition, there are two indirect pathways that involve intermediate agents released upon interaction with bile acids receptors in the gut. Activation of intestinal FXR and TGR5 receptors can result in the release of fibroblast growth factor 19 (FGF19) and glucagon-like peptide 1 (GLP-1), both capable of signaling to the CNS. We conclude that when plasma bile acids levels are high all three pathways may contribute in signal transmission to the CNS. However, under normal physiological circumstances, the indirect pathway involving GLP-1 may evoke the most substantial effect in the brain.
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Affiliation(s)
- Kim L Mertens
- Master's Program in Biomedical Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Laboratory of Endocrinology, Department Clinical Chemistry, Academic Medical Centre, University of Amsterdam, Amsterdam, Netherlands.,Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
| | - Maarten R Soeters
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Hannah M Eggink
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Department of Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, Netherlands
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65
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Abstract
Hepatic encephalopathy describes the array of neurological alterations that occur during acute liver failure or chronic liver injury. While key players in the pathogenesis of hepatic encephalopathy, such as increases in brain ammonia, alterations in neurosteroid levels, and neuroinflammation, have been identified, there is still a paucity in our knowledge of the precise pathogenic mechanism. This review gives a brief overview of our understanding of the pathogenesis of hepatic encephalopathy and then summarizes the significant recent advances made in clinical and basic research contributing to our understanding, diagnosis, and possible treatment of hepatic encephalopathy. A literature search using the PubMed database was conducted in May 2017 using "hepatic encephalopathy" as a keyword, and selected manuscripts were limited to those research articles published since May 2014. While the authors acknowledge that many significant advances have been made in the understanding of hepatic encephalopathy prior to May 2014, we have limited the scope of this review to the previous three years only.
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Affiliation(s)
- Victoria Liere
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, TX, USA
| | | | - Sharon DeMorrow
- Department of Medical Physiology, College of Medicine, Texas A&M Health Science Center, Temple, TX, USA
- Central Texas Veterans Healthcare System, Temple, TX, USA
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66
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Higashi T, Watanabe S, Tomaru K, Yamazaki W, Yoshizawa K, Ogawa S, Nagao H, Minato K, Maekawa M, Mano N. Unconjugated bile acids in rat brain: Analytical method based on LC/ESI-MS/MS with chemical derivatization and estimation of their origin by comparison to serum levels. Steroids 2017; 125:107-113. [PMID: 28689738 DOI: 10.1016/j.steroids.2017.07.001] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 06/26/2017] [Accepted: 07/04/2017] [Indexed: 01/30/2023]
Abstract
Although some studies have revealed the implication of bile acids (BAs) and neurological diseases, the levels and origin of the BAs in the brain are not fully understood. In this study, we first developed and validated a sensitive and specific method for the determination of three unconjugated BAs [cholic acid (CA), chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA)] in the rat brain by liquid chromatography/electrospray ionization-tandem mass spectrometry combined with chemical derivatization. The measured brain concentrations (mean±standard deviation, n=10) of normal rats were 58.7±48.8, 14.2±11.7 and 13.2±8.7ng/g tissue for CA, CDCA and DCA, respectively. For their origin, we developed the hypothesis that they might be mostly derived from the periphery. To test this hypothesis, the brain BA levels were compared with the serum levels. The brain levels had high correlations with the serum levels, and were always lower than the serum levels for the three unconjugated BAs. Furthermore, the higher brain-to-serum concentration ratios were found for the BAs with higher logD values (higher lipophilicity). Moreover, the brains of the rats intraperitoneally administered with deuterium-labeled CA and CDCA were also analyzed; the deuterium-labeled BAs were detected in the brain of the rats administered with these compounds. Based on all the results, we concluded that the BAs found in the brain are mostly derived from the periphery and the major mechanism for the transportation of the unconjugated BAs to the brain is by passive diffusion.
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Affiliation(s)
- Tatsuya Higashi
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
| | - Shui Watanabe
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Koki Tomaru
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Wataru Yamazaki
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Kazumi Yoshizawa
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Shoujiro Ogawa
- Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Hidenori Nagao
- Pharmacokinetics Research Department, ASKA Pharmaceutical Co., Ltd., 5-36-1, Shimosakunobe, Takatsu-ku, Kawasaki 213-8522, Japan
| | - Kouichi Minato
- Pharmacokinetics Research Department, ASKA Pharmaceutical Co., Ltd., 5-36-1, Shimosakunobe, Takatsu-ku, Kawasaki 213-8522, Japan
| | - Masamitsu Maekawa
- Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
| | - Nariyasu Mano
- Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai 980-8574, Japan
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67
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McMillin M, Frampton G, Grant S, Khan S, Diocares J, Petrescu A, Wyatt A, Kain J, Jefferson B, DeMorrow S. Bile Acid-Mediated Sphingosine-1-Phosphate Receptor 2 Signaling Promotes Neuroinflammation during Hepatic Encephalopathy in Mice. Front Cell Neurosci 2017; 11:191. [PMID: 28725183 PMCID: PMC5496949 DOI: 10.3389/fncel.2017.00191] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 06/20/2017] [Indexed: 12/16/2022] Open
Abstract
Hepatic encephalopathy (HE) is a neuropsychiatric complication that occurs due to deteriorating hepatic function and this syndrome influences patient quality of life, clinical management strategies and survival. During acute liver failure, circulating bile acids increase due to a disruption of the enterohepatic circulation. We previously identified that bile acid-mediated signaling occurs in the brain during HE and contributes to cognitive impairment. However, the influences of bile acids and their downstream signaling pathways on HE-induced neuroinflammation have not been assessed. Conjugated bile acids, such as taurocholic acid (TCA), can activate sphingosine-1-phosphate receptor 2 (S1PR2), which has been shown to promote immune cell infiltration and inflammation in other models. The current study aimed to assess the role of bile-acid mediated S1PR2 signaling in neuroinflammation and disease progression during azoxymethane (AOM)-induced HE in mice. Our findings demonstrate a temporal increase of bile acids in the cortex during AOM-induced HE and identified that cortical bile acids were elevated as an early event in this model. In order to classify the specific bile acids that were elevated during HE, a metabolic screen was performed and this assay identified that TCA was increased in the serum and cortex during AOM-induced HE. To reduce bile acid concentrations in the brain, mice were fed a diet supplemented with cholestyramine, which alleviated neuroinflammation by reducing proinflammatory cytokine expression in the cortex compared to the control diet-fed AOM-treated mice. S1PR2 was expressed primarily in neurons and TCA treatment increased chemokine ligand 2 mRNA expression in these cells. The infusion of JTE-013, a S1PR2 antagonist, into the lateral ventricle prior to AOM injection protected against neurological decline and reduced neuroinflammation compared to DMSO-infused AOM-treated mice. Together, this identifies that reducing bile acid levels or S1PR2 signaling are potential therapeutic strategies for the management of HE.
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Affiliation(s)
- Matthew McMillin
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
| | - Gabriel Frampton
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
| | - Stephanie Grant
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
| | - Shamyal Khan
- Department of Internal Medicine, Baylor Scott & White HealthTemple, TX, United States
| | - Juan Diocares
- Department of Internal Medicine, Baylor Scott & White HealthTemple, TX, United States
| | - Anca Petrescu
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
| | - Amy Wyatt
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
| | - Jessica Kain
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
| | - Brandi Jefferson
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
| | - Sharon DeMorrow
- Department of Research, Central Texas Veterans Health Care SystemTemple, TX, United States.,Department of Internal Medicine, College of Medicine, Texas A&M University Health Science CenterTemple, TX, United States
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68
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Zhang JM, Wang XH, Hao LH, Wang H, Zhang XY, Muhammad I, Qi Y, Li GL, Sun XQ. Nrf2 is crucial for the down-regulation of Cyp7a1 induced by arachidonic acid in Hepg2 cells. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2017; 52:21-26. [PMID: 28364638 DOI: 10.1016/j.etap.2017.03.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 06/07/2023]
Abstract
In former research, cyp7a1 expression was decreased but Nrf2 transcription and hepatic arachidonic acid (AA) concentration were increased in high-fat diet fed mice. This study aims to investigate the influence of AA in CYP7A1 expression and the role of Nrf2 in regulating CYP7A1 in the process. HepG2 cells were administered with different concentrations of AA. Nrf2 and CYP7A1 expressions were analyzed by real-time PCR and western blot. Nrf2 silenced and over-expressed cell models were constructed by Nrf2 siRNA and eukaryotic expression vector transient transfections and were used to investigate the role of Nrf2 in regulating CYP7A1 following AA administration. The results showed that Nrf2 was increased dose-dependently but CYP7A1 was decreased dose-dependently in cells treated with increasing concentrations of AA. The expression of CYP7A1 was increased by Nrf2 silence and was decreased by Nrf2 over-expression in HepG2 cells treated with different concentrations of AA. In conclusion, Nrf2 plays a significant role in the down-regulation of CYP7A1 induced by AA in HepG2 cells.
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Affiliation(s)
- Jin-Ming Zhang
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Xing-He Wang
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Li-Hong Hao
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - He Wang
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Xiu-Ying Zhang
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Ishfaq Muhammad
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Yue Qi
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Guang-Liang Li
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
| | - Xiao-Qi Sun
- Faculty of Basic Veterinary Science, College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, PR China.
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69
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Nizamutdinov D, DeMorrow S, McMillin M, Kain J, Mukherjee S, Zeitouni S, Frampton G, Bricker PCS, Hurst J, Shapiro LA. Hepatic alterations are accompanied by changes to bile acid transporter-expressing neurons in the hypothalamus after traumatic brain injury. Sci Rep 2017; 7:40112. [PMID: 28106051 PMCID: PMC5247752 DOI: 10.1038/srep40112] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 12/02/2016] [Indexed: 12/29/2022] Open
Abstract
Annually, there are over 2 million incidents of traumatic brain injury (TBI) and treatment options are non-existent. While many TBI studies have focused on the brain, peripheral contributions involving the digestive and immune systems are emerging as factors involved in the various symptomology associated with TBI. We hypothesized that TBI would alter hepatic function, including bile acid system machinery in the liver and brain. The results show activation of the hepatic acute phase response by 2 hours after TBI, hepatic inflammation by 6 hours after TBI and a decrease in hepatic transcription factors, Gli 1, Gli 2, Gli 3 at 2 and 24 hrs after TBI. Bile acid receptors and transporters were decreased as early as 2 hrs after TBI until at least 24 hrs after TBI. Quantification of bile acid transporter, ASBT-expressing neurons in the hypothalamus, revealed a significant decrease following TBI. These results are the first to show such changes following a TBI, and are compatible with previous studies of the bile acid system in stroke models. The data support the emerging idea of a systemic influence to neurological disorders and point to the need for future studies to better define specific mechanisms of action.
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Affiliation(s)
- Damir Nizamutdinov
- Department of Surgery, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA.,Department of Neurosurgery, Neuroscience Research Institute, Baylor Scott &White Health, Temple, Texas, 76504, USA
| | - Sharon DeMorrow
- Departent of Internal Medicine, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA.,Central Texas Veterans Health Care System, Temple, Texas, 76504, USA
| | - Matthew McMillin
- Departent of Internal Medicine, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA.,Central Texas Veterans Health Care System, Temple, Texas, 76504, USA
| | - Jessica Kain
- Department of Surgery, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA
| | - Sanjib Mukherjee
- Department of Surgery, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA
| | - Suzanne Zeitouni
- Department of Surgery, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA
| | - Gabriel Frampton
- Departent of Internal Medicine, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA.,Central Texas Veterans Health Care System, Temple, Texas, 76504, USA
| | - Paul Clint S Bricker
- Department of Surgery, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA
| | - Jacob Hurst
- Department of Surgery, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA
| | - Lee A Shapiro
- Department of Surgery, Texas A&M University Health Science Center, College of Medicine, Temple, Texas, 76504, USA.,Department of Neurosurgery, Neuroscience Research Institute, Baylor Scott &White Health, Temple, Texas, 76504, USA
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70
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Huang C, Wang J, Hu W, Wang C, Lu X, Tong L, Wu F, Zhang W. Identification of functional farnesoid X receptors in brain neurons. FEBS Lett 2016; 590:3233-42. [PMID: 27545319 DOI: 10.1002/1873-3468.12373] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 12/22/2022]
Abstract
Farnesoid X receptor (FXR) has been confirmed to sense bile acids in various tissues. However, its expression in brain neurons remains obscure. In this study, we identified FXR mRNA and protein expression in mouse brain neurons and in mouse/human brain tissues. FXR was predominantly localized in the nucleus in cultured neurons, but in neurons in vivo, it mainly appeared in the cytoplasm. In nuclear compartments, the neuronal FXR exhibited a punctate distribution. Activation of FXR increased the small heterodimer partner (SHP) mRNA and protein expression levels in cultured neurons and in brain tissues. These findings will help explore new functions of FXR in the brain.
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Affiliation(s)
- Chao Huang
- Department of Pharmacology, School of Pharmacy, Nantong University, China.,Key Laboratory of Inflammation and Molecular Drug Target of Jiangsu, Nantong, China
| | - Jili Wang
- Department of Pharmacology, School of Pharmacy, Nantong University, China.,Key Laboratory of Inflammation and Molecular Drug Target of Jiangsu, Nantong, China
| | - Wenfeng Hu
- Department of Pharmacology, School of Pharmacy, Nantong University, China.,Key Laboratory of Inflammation and Molecular Drug Target of Jiangsu, Nantong, China
| | - Chengniu Wang
- Basic Medical Research Center, Medical College, Nantong University, China
| | - Xu Lu
- Department of Pharmacology, School of Pharmacy, Nantong University, China.,Key Laboratory of Inflammation and Molecular Drug Target of Jiangsu, Nantong, China
| | - Lijuan Tong
- Department of Pharmacology, School of Pharmacy, Nantong University, China.,Key Laboratory of Inflammation and Molecular Drug Target of Jiangsu, Nantong, China
| | - Feng Wu
- Department of Pharmacology, School of Pharmacy, Nantong University, China.,Key Laboratory of Inflammation and Molecular Drug Target of Jiangsu, Nantong, China
| | - Wei Zhang
- Department of Pharmacology, School of Pharmacy, Nantong University, China. .,Key Laboratory of Inflammation and Molecular Drug Target of Jiangsu, Nantong, China.
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McMillin M, Grant S, Frampton G, Andry S, Brown A, DeMorrow S. Fractalkine suppression during hepatic encephalopathy promotes neuroinflammation in mice. J Neuroinflammation 2016; 13:198. [PMID: 27561705 PMCID: PMC5000400 DOI: 10.1186/s12974-016-0674-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2015] [Accepted: 08/17/2016] [Indexed: 12/31/2022] Open
Abstract
Background Acute liver failure is associated with numerous systemic consequences including neurological dysfunction, termed hepatic encephalopathy, which contributes to mortality and is a challenge to manage in the clinic. During hepatic encephalopathy, microglia activation and neuroinflammation occur due to dysregulated cell signaling and an increase of toxic metabolites in the brain. Fractalkine is a chemokine that is expressed primarily in neurons and through signaling with its receptor CX3CR1 on microglia, leads to microglia remaining in a quiescent state. Fractalkine is often suppressed during neuropathies that are characterized by neuroinflammation. However, the expression and subsequent role of fractalkine on microglia activation and the pathogenesis of hepatic encephalopathy due to acute liver failure is unknown. Methods Hepatic encephalopathy was induced in mice via injection of azoxymethane (AOM) or saline for controls. Subsets of these mice were implanted with osmotic minipumps that infused soluble fractalkine or saline into the lateral ventricle of the brain. Neurological decline and the latency to coma were recorded in these mice, and brain, serum, and liver samples were collected. Neurons or microglia were isolated from whole brain samples using immunoprecipitation. Liver damage was assessed using hematoxylin and eosin staining and by measuring serum liver enzyme concentrations. Fractalkine and CX3CR1 expression were assessed by real-time PCR, and proinflammatory cytokine expression was assessed using ELISA assays. Results Following AOM administration, fractalkine expression is suppressed in the cortex and in isolated neurons compared to vehicle-treated mice. CX3CR1 is suppressed in isolated microglia from AOM-treated mice. Soluble fractalkine infusion into the brain significantly reduced neurological decline in AOM-treated mice compared to saline-infused AOM-treated mice. Infusion of soluble fractalkine into AOM-treated mice reduced liver damage, lessened microglia activation, and suppressed expression of chemokine ligand 2, interleukin-6, and tumor necrosis factor alpha compared to saline-infused mice. Conclusions These findings suggest that fractalkine-mediated signaling is suppressed in the brain following the development of hepatic encephalopathy. Supplementation of AOM-treated mice with soluble fractalkine led to improved outcomes, which identifies this pathway as a possible therapeutic target for the management of hepatic encephalopathy following acute liver injury.
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Affiliation(s)
- Matthew McMillin
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA.,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA
| | - Stephanie Grant
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA.,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA
| | - Gabriel Frampton
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA.,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA
| | - Sarah Andry
- Department of Internal Medicine, Baylor Scott & White Health, 2401 S. 31st Street, Temple, TX, 76508, USA
| | - Adam Brown
- Department of Internal Medicine, Baylor Scott & White Health, 2401 S. 31st Street, Temple, TX, 76508, USA
| | - Sharon DeMorrow
- Department of Internal Medicine, Texas A&M Health Science Center, College of Medicine, Temple, TX, USA. .,Central Texas Veterans Healthcare System, 1901 S. 1st Street, Building 205, Temple, TX, 76504, USA.
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McMillin M, DeMorrow S. Effects of bile acids on neurological function and disease. FASEB J 2016; 30:3658-3668. [PMID: 27468758 DOI: 10.1096/fj.201600275r] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/18/2016] [Indexed: 12/14/2022]
Abstract
Bile acids are synthesized from cholesterol and are known to be involved with the emulsification and digestion of dietary lipids and fat-soluble vitamins. Outside of this role, bile acids can act as cell signaling effectors through binding and activating receptors on both the cell membrane and nucleus. Numerous reports have investigated these signaling pathways in conditions where the liver is damaged. More recently, effort has been made to investigate the role of bile acids in diseases outside of those associated with liver damage. This review summarizes recent findings on the influences that bile acids can exert in normal neurological function and their contribution to diseases of the nervous system, with the intent of highlighting the role of these metabolites as potential players in neurological disorders.-McMillin, M., DeMorrow, S. Effects of bile acids on neurological function and disease.
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Affiliation(s)
- Matthew McMillin
- Texas A&M University Health Science Center, College of Medicine, Department of Internal Medicine, Temple, Texas, USA; and.,Central Texas Veterans Health Care System, Temple, Texas, USA
| | - Sharon DeMorrow
- Texas A&M University Health Science Center, College of Medicine, Department of Internal Medicine, Temple, Texas, USA; and .,Central Texas Veterans Health Care System, Temple, Texas, USA
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