1001
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Xu YF, Yang XQ, Lu XF, Guo S, Liu Y, Iqbal M, Ning SL, Yang H, Suo N, Chen YX. Fibroblast growth factor receptor 4 promotes progression and correlates to poor prognosis in cholangiocarcinoma. Biochem Biophys Res Commun 2014; 446:54-60. [PMID: 24565842 DOI: 10.1016/j.bbrc.2014.02.050] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 02/11/2014] [Indexed: 01/04/2023]
Abstract
Fibroblast growth factor receptor 4 (FGFR4) is related to poor prognosis of several cancers, but the correlation between FGFR4 expression and cholangiocarcinoma (CCA) has not been well elucidated. We investigated the expression of FGFR4 in 83 intrahepatic cholangiocarcinomas (IHCCs), 75 perihilar cholangiocarcinomas (PHCCs) and 41 distal cholangiocarcinomas (DCCs) by immunohistochemistry (IHC), and subsequently evaluated association of FGFR4 with clinicopathologic parameters and survival rate. The rate of FGFR4 higher expression was 61.4% (51/83) in IHCCs, 53.3% (40/75) in PHCCs and 56.1% (23/41) in DCCs. FGFR4 expression was significantly related to poor prognosis of IHCC (P=0.002) and PHCC (P=0.019) with univariate analysis, and also identified as an independent prognostic factor in IHCC (P=0.045) and PHCC (P=0.049) with multivariate analysis. Additionally, with functional assays in vitro, we found FGFR4 can induce proliferation, invasion and epithelial-mesenchymal transition (EMT) of CCA cell lines with FGF19 stimulation. Moreover, FGFR4 inhibitor AP24354 can suppress proliferation, invasion and induce apoptosis of CCA cells. In conclusion, FGFR4 expression can be identified as a significant independent prognostic biomarker of IHCC and PHCC. FGFR4 played a pivotal role in proliferation, invasion and EMT of CCA. FGFR4 inhibitor can suppress proliferation, invasion and induce apoptosis of CCA, indicating that FGFR4 may act as a potential therapeutic target.
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Affiliation(s)
- Yun-Fei Xu
- Department of Hepatobiliary Surgery, Qilu Hospital of Shandong University, China
| | | | - Xiao-Fei Lu
- Department of Gastrointestinal Surgery, Jinan Central Hospital, China
| | - Sen Guo
- Department of Hepatobiliary Surgery, Qilu Hospital of Shandong University, China
| | - Yi Liu
- Department of Hepatobiliary Surgery, Qilu Hospital of Shandong University, China
| | - Mohammad Iqbal
- Department of Hepatobiliary Surgery, Qilu Hospital of Shandong University, China
| | - Shang-Lei Ning
- Department of Hepatobiliary Surgery, Qilu Hospital of Shandong University, China
| | - Hui Yang
- Department of Hepatobiliary Surgery, Qilu Hospital of Shandong University, China
| | - Ning Suo
- Department of Anatomy, Shandong University, China
| | - Yu-Xin Chen
- Department of Hepatobiliary Surgery, Qilu Hospital of Shandong University, China.
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1002
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Kunne C, Acco A, Duijst S, de Waart DR, Paulusma CC, Gaemers I, Oude Elferink RPJ. FXR-dependent reduction of hepatic steatosis in a bile salt deficient mouse model. Biochim Biophys Acta Mol Basis Dis 2014; 1842:739-46. [PMID: 24548803 DOI: 10.1016/j.bbadis.2014.02.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 02/05/2014] [Accepted: 02/09/2014] [Indexed: 12/14/2022]
Abstract
It has been established that bile salts play a role in the regulation of hepatic lipid metabolism. Accordingly, overt signs of steatosis have been observed in mice with reduced bile salt synthesis. The aim of this study was to identify the mechanism of hepatic steatosis in mice with bile salt deficiency due to a liver specific disruption of cytochrome P450 reductase. In this study mice lacking hepatic cytochrome P450 reductase (Hrn) or wild type (WT) mice were fed a diet supplemented with or without either 0.1% cholic acid (CA) or 0.025% obeticholic acid, a specific FXR-agonist. Feeding a CA-supplemented diet resulted in a significant decrease of plasma ALT in Hrn mice. Histologically, hepatic steatosis ameliorated after CA feeding and this was confirmed by reduced hepatic triglyceride content (115.5±7.3mg/g liver and 47.9±4.6mg/g liver in control- and CA-fed Hrn mice, respectively). The target genes of FXR-signaling were restored to normal levels in Hrn mice when fed cholic acid. VLDL secretion in both control and CA-fed Hrn mice was reduced by 25% compared to that in WT mice. In order to gain insight in the mechanism behind these bile salt effects, the FXR agonist also was administered for 3weeks. This resulted in a similar decrease in liver triglycerides, indicating that the effect seen in bile salt fed Hrn animals is FXR dependent. In conclusion, steatosis in Hrn mice is ameliorated when mice are fed bile salts. This effect is FXR dependent. Triglyceride accumulation in Hrn liver may partly involve impaired VLDL secretion.
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Affiliation(s)
- Cindy Kunne
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
| | - Alexandra Acco
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands; Department of Pharmacology, Federal University of Paraná, Curitiba, Paraná, Brazil
| | - Suzanne Duijst
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
| | - Dirk R de Waart
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
| | - Coen C Paulusma
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
| | - Ingrid Gaemers
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands
| | - Ronald P J Oude Elferink
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, The Netherlands.
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1003
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Scorletti E, Byrne CD. Omega-3 fatty acids, hepatic lipid metabolism, and nonalcoholic fatty liver disease. Annu Rev Nutr 2014; 33:231-48. [PMID: 23862644 DOI: 10.1146/annurev-nutr-071812-161230] [Citation(s) in RCA: 210] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Long-chain omega-3 fatty acids belong to a family of polyunsaturated fatty acids that are known to have important beneficial effects on metabolism and inflammation. Such effects may confer a benefit in specific chronic noncommunicable diseases that are becoming very prevalent in Westernized societies [e.g., nonalcoholic fatty liver disease (NAFLD)]. Typically, with a Westernized diet, long-chain omega-6 fatty acid consumption is markedly greater than omega-3 fatty acid consumption. The potential consequences of an alteration in the ratio of omega-6 to omega-3 fatty acid consumption are increased production of proinflammatory arachidonic acid-derived eicosanoids and impaired regulation of hepatic and adipose function, predisposing to NAFLD. NAFLD represents a spectrum of liver fat-related conditions that originates with ectopic fat accumulation in liver (hepatic steatosis) and progresses, with the development of hepatic inflammation and fibrosis, to nonalcoholic steatohepatitis (NASH). If the adipose tissue is inflamed with widespread macrophage infiltration, the production of adipokines may act to exacerbate liver inflammation and NASH. Omega-3 fatty acid treatment may have beneficial effects in regulating hepatic lipid metabolism, adipose tissue function, and inflammation. Recent studies testing the effects of omega-3 fatty acids in NAFLD are showing promise and suggesting that these fatty acids may be useful in the treatment of NAFLD. To date, further research is needed in NAFLD to (a) establish the dose of long-chain omega-3 fatty acids as a treatment, (b) determine the duration of therapy, and (c) test whether there is benefit on the different component features of NAFLD (hepatic fat, inflammation, and fibrosis).
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Affiliation(s)
- E Scorletti
- Nutrition and Metabolism, Human Development and Health Academic Unit, University of Southampton and National Institute for Health Research Southampton Biomedical Research Center, Southampton University Hospitals National Health Service Trust, Southampton General Hospital, Southampton SO16 6YD, United Kingdom
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1004
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Su Y, Zhang Y, Chen M, Jiang Z, Sun L, Wang T, Zhang L. Lipopolysaccharide exposure augments isoniazide-induced liver injury. J Appl Toxicol 2014; 34:1436-42. [PMID: 25331106 DOI: 10.1002/jat.2979] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 11/25/2013] [Accepted: 11/25/2013] [Indexed: 12/21/2022]
Abstract
Isoniazide (INH) is a classic antituberculosis drug associated with clinical idiosyncratic drug-induced liver injury. It has been hypothesized that the interaction between a drug and modest inflammation results in a decreased threshold for drug toxicity. In this study, we tested the hypothesis that INH causes liver injury in rats when coadministered with lipopolysaccharide (LPS). Neither INH nor LPS alone caused liver injury. The coadministration of INH and LPS was associated with increases in serum and histopathological markers of liver injury. Tumour necrosis factor-α expression was significantly increased in the coadministered group. The downregulation of the bile acid transporter, bile salt export pump, and multidrug resistance protein 2 at both mRNA and protein levels was observed. Furthermore, the level of Farnesoid X receptor, which regulates the bile salt export pump and multidrug resistance protein 2, were clearly decreased. These results indicate that the coadministration of nontoxic doses of LPS and INH causes liver injury; the disruption of biliary excretion is considered the primary inflammation-related characteristic of INH-induced hepatotoxicity.
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Affiliation(s)
- Yijing Su
- Jiangsu Center of Drug Screening, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, 210009, Jiangsu Province, People's Republic of China
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1005
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Chen G, Wang H, Zhang X, Yang ST. Nutraceuticals and Functional Foods in the Management of Hyperlipidemia. Crit Rev Food Sci Nutr 2014; 54:1180-201. [DOI: 10.1080/10408398.2011.629354] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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1006
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Liu P, Xu X, Chen L, Ma L, Shen X, Hu L. Discovery and SAR study of hydroxyacetophenone derivatives as potent, non-steroidal farnesoid X receptor (FXR) antagonists. Bioorg Med Chem 2014; 22:1596-607. [PMID: 24513188 DOI: 10.1016/j.bmc.2014.01.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 01/17/2014] [Accepted: 01/20/2014] [Indexed: 11/26/2022]
Abstract
Compound 1 (IC50=35.2 ± 7.2 μM), a moderate FXR antagonist was discovered via high-throughput screening. Structure-activity relationship studies indicated that the shape and the lipophilicity of the substituents of the aromatic ring affect the activity dramatically, increasing the shape and the lipophilicity of the substituents of the aromatic ring enhances the potency of FXR antagonists. Especially, when the OH at C2 position of the aromatic ring was replaced by the OBn substituent (analog 2b), its activity could be improved to IC50=1.1 ± 0.1μM. Besides, the length of the linker and the tetrazole structure are essential for retaining the activity.
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Affiliation(s)
- Peng Liu
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China
| | - Xing Xu
- Shanghai Research Center for Modernization of Traditional Chinese Medicine, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Lili Chen
- Shanghai Research Center for Modernization of Traditional Chinese Medicine, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China
| | - Lei Ma
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China
| | - Xu Shen
- Shanghai Research Center for Modernization of Traditional Chinese Medicine, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China.
| | - Lihong Hu
- Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, Shanghai 200237, PR China; Shanghai Research Center for Modernization of Traditional Chinese Medicine, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, PR China.
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1007
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Styer AM, Roesch SL, Argyropoulos G. Modulation of fibroblast growth factor 19 expression by bile acids, meal replacement and energy drinks, milk, and coffee. PLoS One 2014; 9:e85558. [PMID: 24465600 PMCID: PMC3896408 DOI: 10.1371/journal.pone.0085558] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/29/2013] [Indexed: 12/31/2022] Open
Abstract
Background The enterohepatic pathway involving the fibroblast growth factor 19 (FGF19) and bile acids (BA) has been linked with the etiology and remission of type 2 diabetes (T2D) following Roux-en-Y gastric bypass (RYGB) surgery. Specifically, diabetic patients had lower FGF19 circulating levels but postoperative FGF19 and BA levels were higher in diabetic patients that experience remission of T2D, as compared to non-diabetic patients and diabetic patients that do not experience remission. It has been proposed that this may be due to the direct flow of digestate-free bile acids into the ileum benefiting mostly T2D patients without severe diabetes. Methods/Results We used a human colorectal cell line (LS174T) that endogenously expresses FGF19, real time PCR, and Elisas for precise quantitation of FGF19 mRNA and secreted protein levels. We report here that BA and fractions of BA stimulated FGF19 in vitro but this effect was partially blocked when BA were pre-incubated with a lipoprotein mix which emulates digested food. In addition, we show that FGF19 mRNA was stimulated by meal replacement drinks (Ensure, Glucerna, SlimFast), non-fat milk, and coffee which has been linked with reduced risk for developing diabetes. Pure caffeine and the 5-hour Energy drink, on the other hand, decreased FGF19 mRNA. Conclusions In summary, FGF19 expression in vitro is modifiable by popular drinks suggesting that such approaches could potentially be used for modulating FGF19 expression in humans.
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Affiliation(s)
- Amanda M. Styer
- Weis Center for Research, Geisinger Health System, Danville, Pennsylvania, United States of America
| | - Stephen L. Roesch
- Weis Center for Research, Geisinger Health System, Danville, Pennsylvania, United States of America
| | - George Argyropoulos
- Weis Center for Research, Geisinger Health System, Danville, Pennsylvania, United States of America
- Institute of Obesity, Geisinger Health System, Danville, Pennsylvania, United States of America
- * E-mail:
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1008
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Kong B, Guo GL. Soluble expression of disulfide bond containing proteins FGF15 and FGF19 in the cytoplasm of Escherichia coli. PLoS One 2014; 9:e85890. [PMID: 24465767 PMCID: PMC3896424 DOI: 10.1371/journal.pone.0085890] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 12/06/2013] [Indexed: 01/30/2023] Open
Abstract
Fibroblast growth factor 19 (FGF19) is the human ortholog of mouse FGF15, and both proteins function as an endocrine signal to regulate various liver functions. FGF15/FGF19 protein contains two disulfide bonds. It is unfavorable to form disulfide bonds in Escherichia coli (E. coli) cytoplasm because of the bacterial cytoplasmic reducing environment. Modification of the cytoplasmic reducing environment and/or co-expression of protein chaperones are common strategies to express disulfide bond containing proteins in E. coli. In the current study, we report a method to produce soluble FGF15/FGF19 protein in cytoplasm of E. coli. Several commercial available strains with the disruption of thiol-redox pathways, and/or co-expression of redoxase or refolding chaperones were used to develop this novel method for expression of FGF15/FGF19 in E. coli. Mutation of the thiol-disulfide bond reducing pathway in E. coli or N-terminal fusion of thioredox (TRX) alone is not enough to support disulfide bond formation in FGF15/19 proteins. However, TRX fusion protein improved FGF19 solubility in strains of thiol-redox system mutants. In addition, DsbC co-expressed in thiol-redox system mutants alone improved and further enhanced FGF19 solubility with combination of TRX fusion tag. The soluble FGF19 proteins were easily purified through Ni-NTA affinity chromatography and anion exchange chromatography, and the purified protein maintained its biological activities, confirmed by suppressing hepatic Cyp7a1 gene transcription in mice and by activating ERK1/2 signaling pathway in HepG2 cells. In contrast, soluble FGF15 protein in cytoplasm remained very low using these strategies. In summary, we have successfully developed a method to express functional FGF19 protein in prokaryotic cells, and this strategy may be adapted for the expression of other disulfide-containing proteins.
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Affiliation(s)
- Bo Kong
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Grace L. Guo
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey, United States of America
- * E-mail:
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1009
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Theriot CM, Young VB. Microbial and metabolic interactions between the gastrointestinal tract and Clostridium difficile infection. Gut Microbes 2014; 5:86-95. [PMID: 24335555 PMCID: PMC4049944 DOI: 10.4161/gmic.27131] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Antibiotics disturb the gastrointestinal tract microbiota and in turn reduce colonization resistance against Clostridium difficile. The mechanism for this loss of colonization resistance is still unknown but likely reflects structural (microbial) and functional (metabolic) changes to the gastrointestinal tract. Members of the gut microbial community shape intestinal metabolism that provides nutrients and ultimately supports host immunity. This review will discuss how antibiotics alter the structure of the gut microbiota and how this impacts bacterial metabolism in the gut. It will also explore the chemical requirements for C. difficile germination, growth, toxin production and sporulation. Many of the metabolites that influence C. difficile physiology are products of gut microbial metabolism including bile acids, carbohydrates and amino acids. To restore colonization resistance against C. difficile after antibiotics a targeted approach restoring both the structure and function of the gastrointestinal tract is needed.
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1010
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Mishra S, Somvanshi PR, Venkatesh KV. Control of cholesterol homeostasis by entero-hepatic bile transport – the role of feedback mechanisms. RSC Adv 2014. [DOI: 10.1039/c4ra09397f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cholesterol homeostasis is achieved through a tight regulation between synthesis, dietary absorption, utilization of bile salts, and excretion in the entero-hepatic compartment.
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Affiliation(s)
- Shekhar Mishra
- Department of Chemical Engineering
- Indian Institute of Technology Bombay
- Mumbai 400076, India
| | - Pramod R. Somvanshi
- Department of Chemical Engineering
- Indian Institute of Technology Bombay
- Mumbai 400076, India
| | - K. V. Venkatesh
- Department of Chemical Engineering
- Indian Institute of Technology Bombay
- Mumbai 400076, India
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1011
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García-Cañaveras JC, Donato MT, Lahoz A. Ultra-performance liquid chromatography-mass spectrometry targeted profiling of bile acids: application to serum, liver tissue, and cultured cells of different species. Methods Mol Biol 2014; 1198:233-247. [PMID: 25270933 DOI: 10.1007/978-1-4939-1258-2_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Currently, there is increasing interest in developing accurate methods for the quantitative analysis of bile acids (BAs) in biological samples. We have developed a sensitive, fast, and reproducible UPLC-MRM-MS method for BA profiling in serum, liver tissue, or cultured cells of different species (human, rat, and mouse). This method, validated according to FDA guidelines, allows the quantification of 12 non-conjugated, 8 glycine-conjugated, and 11 taurine-conjugated BAs, using 5 additional deuterated BAs as internal standards in a single analytical run. The main features of this analytical approach are its high sensitivity, low sample requirements, versatility, and comprehensive capacity to profile a considerable number of BAs in samples of different species, which make it a valuable tool with potential applications in many research areas focusing on BAs, particularly in toxicological studies.
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Affiliation(s)
- Juan Carlos García-Cañaveras
- Biomarkers and Metabolmics Unidad de Hepatología Experimental, Instituto de Investigación Sanitaria, Fundación Hospital La Fe, Av. Campanar 21, Valencia, 46009, Spain
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1012
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Pavagadhi S, Natera S, Roessner U, Balasubramanian R. Insights into lipidomic perturbations in zebrafish tissues upon exposure to microcystin-LR and microcystin-RR. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:14376-14384. [PMID: 24152164 DOI: 10.1021/es4004125] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This work represents the first study of its kind that was conducted to evaluate changes in lipid metabolic networks following a balneation exposure of adult zebrafish to MCLR (microcystin-leucine-arginine) and MCRR (microcystin-arginine-arginine) at a sublethal dose (10 μg L(-1)) for a period of 30 days. Following the exposure to MCLR and MCRR, gills, liver, intestine, and brain tissues were harvested for metabolite extraction. Extracted metabolites were detected using qTOF-LC-MS (time-of-flight-liquid chromatography-mass spectrometry). Metabolites were identified using Kegg pathways. The identified metabolites are shown on lipid biochemical maps to demonstrate major perturbations in the metabolic machinery. Results showed that most of the metabolic pathways under the lipid class were affected in different tissues of zebrafish following the exposure to MCLR and MCRR (10 μg L(-1) for 30 days). The kind and flux of metabolic perturbations varied among different tissues of the organs after the exposure to MCLR and MCRR with the tissues of gills being the most affected. Among the various lipid pathways, cholesterol synthesis was affected significantly as observed from the highest number of perturbed metabolites in that pathway. Cholesterol is responsible for synthesis of steroid hormones and bile acids, which have been recognized as endocrine signaling molecules. Disruption in the synthesis of these compounds following MCLR/MCRR exposure suggests that MCs are capable of causing endocrine disruption among aquatic organisms even under sublethal conditions. Apart from cholesterol synthesis, various other metabolic pathways belonging to the class of essential fatty acids and lipid oxidation were also observed to be perturbed following a balneation exposure of zebrafish to MCLR/MCRR.
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Affiliation(s)
- Shruti Pavagadhi
- Singapore-Delft Water Alliance and ‡Department of Civil and Environmental Engineering National University of Singapore , Block E1A, #07-03 No.1 Engineering Drive 2, Singapore 117576
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1013
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Fisher CP, Plant NJ, Moore JB, Kierzek AM. QSSPN: dynamic simulation of molecular interaction networks describing gene regulation, signalling and whole-cell metabolism in human cells. Bioinformatics 2013; 29:3181-90. [PMID: 24064420 PMCID: PMC3842758 DOI: 10.1093/bioinformatics/btt552] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 09/03/2013] [Accepted: 09/18/2013] [Indexed: 12/11/2022] Open
Abstract
MOTIVATION Dynamic simulation of genome-scale molecular interaction networks will enable the mechanistic prediction of genotype-phenotype relationships. Despite advances in quantitative biology, full parameterization of whole-cell models is not yet possible. Simulation methods capable of using available qualitative data are required to develop dynamic whole-cell models through an iterative process of modelling and experimental validation. RESULTS We formulate quasi-steady state Petri nets (QSSPN), a novel method integrating Petri nets and constraint-based analysis to predict the feasibility of qualitative dynamic behaviours in qualitative models of gene regulation, signalling and whole-cell metabolism. We present the first dynamic simulations including regulatory mechanisms and a genome-scale metabolic network in human cell, using bile acid homeostasis in human hepatocytes as a case study. QSSPN simulations reproduce experimentally determined qualitative dynamic behaviours and permit mechanistic analysis of genotype-phenotype relationships. AVAILABILITY AND IMPLEMENTATION The model and simulation software implemented in C++ are available in supplementary material and at http://sysbio3.fhms.surrey.ac.uk/qsspn/.
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Affiliation(s)
- Ciarán P Fisher
- Faculty of Health and Medical Sciences, School of Biosciences and Medicine, University of Surrey, Guildford, Surrey GU2 7XH, UK
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1014
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Haeusler RA, Astiarraga B, Camastra S, Accili D, Ferrannini E. Human insulin resistance is associated with increased plasma levels of 12α-hydroxylated bile acids. Diabetes 2013; 62:4184-91. [PMID: 23884887 PMCID: PMC3837033 DOI: 10.2337/db13-0639] [Citation(s) in RCA: 330] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bile acids (BAs) exert pleiotropic metabolic effects, and physicochemical properties of different BAs affect their function. In rodents, insulin regulates BA composition, in part by regulating the BA 12α-hydroxylase CYP8B1. However, it is unclear whether a similar effect occurs in humans. To address this question, we examined the relationship between clamp-measured insulin sensitivity and plasma BA composition in a cohort of 200 healthy subjects and 35 type 2 diabetic (T2D) patients. In healthy subjects, insulin resistance (IR) was associated with increased 12α-hydroxylated BAs (cholic acid, deoxycholic acid, and their conjugated forms). Furthermore, ratios of 12α-hydroxylated/non-12α-hydroxylated BAs were associated with key features of IR, including higher insulin, proinsulin, glucose, glucagon, and triglyceride (TG) levels and lower HDL cholesterol. In T2D patients, BAs were nearly twofold elevated, and more hydrophobic, compared with healthy subjects, although we did not observe disproportionate increases in 12α-hydroxylated BAs. In multivariate analysis of the whole dataset, controlling for sex, age, BMI, and glucose tolerance status, higher 12α-hydroxy/non-12α-hydroxy BA ratios were associated with lower insulin sensitivity and higher plasma TGs. These findings suggest a role for 12α-hydroxylated BAs in metabolic abnormalities in the natural history of T2D and raise the possibility of developing insulin-sensitizing therapeutics based on manipulations of BA composition.
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Affiliation(s)
- Rebecca A. Haeusler
- Department of Medicine, Columbia University, New York, New York
- Corresponding author: Rebecca A. Haeusler,
| | - Brenno Astiarraga
- Department of Clinical and Experimental Medicine, University of Pisa School of Medicine, Pisa, Italy
| | - Stefania Camastra
- Department of Clinical and Experimental Medicine, University of Pisa School of Medicine, Pisa, Italy
| | - Domenico Accili
- Department of Medicine, Columbia University, New York, New York
| | - Ele Ferrannini
- Department of Clinical and Experimental Medicine, University of Pisa School of Medicine, Pisa, Italy
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1015
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Hu M, Yin H, Mitra MS, Liang X, Ajmo JM, Nadra K, Chrast R, Finck BN, You M. Hepatic-specific lipin-1 deficiency exacerbates experimental alcohol-induced steatohepatitis in mice. Hepatology 2013; 58:1953-63. [PMID: 23787969 PMCID: PMC3835749 DOI: 10.1002/hep.26589] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 06/12/2013] [Indexed: 12/22/2022]
Abstract
UNLABELLED Lipin-1 regulates lipid metabolism by way of its function as an enzyme in the triglyceride synthesis pathway and as a transcriptional coregulatory protein and is highly up-regulated in alcoholic fatty liver disease. In the present study, using a liver-specific lipin-1-deficient (lipin-1LKO) mouse model, we aimed to investigate the functional role of lipin-1 in the development of alcoholic steatohepatitis and explore the underlying mechanisms. Alcoholic liver injury was achieved by pair feeding wild-type and lipin-1LKO mice with modified Lieber-DeCarli ethanol-containing low-fat diets for 4 weeks. Surprisingly, chronically ethanol-fed lipin-1LKO mice showed markedly greater hepatic triglyceride and cholesterol accumulation, and augmented elevation of serum liver enzymes accompanied by increased hepatic proinflammatory cytokine expression. Our studies further revealed that hepatic removal of lipin-1 in mice augmented ethanol-induced impairment of hepatic fatty acid oxidation and lipoprotein production, likely by way of deactivation of peroxisome proliferator-activated receptor γ coactivator-1 alpha, a prominent transcriptional regulator of lipid metabolism. CONCLUSIONS Liver-specific lipin-1 deficiency in mice exacerbates the development and progression of experimental alcohol-induced steatohepatitis. Pharmacological or nutritional modulation of hepatic lipin-1 may be beneficial for the prevention or treatment of human alcoholic fatty liver disease.
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Affiliation(s)
- Ming Hu
- Department of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, 12901 Bruce B. Downs Blvd. Tampa, FL 33612, USA
| | - Huquan Yin
- Department of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, 12901 Bruce B. Downs Blvd. Tampa, FL 33612, USA
| | - Mayurranjan S. Mitra
- Department of Medicine, Washington University School of Medicine, St.Louis, MO 63110, USA
| | - Xiaomei Liang
- Department of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, 12901 Bruce B. Downs Blvd. Tampa, FL 33612, USA
| | - Joanne M. Ajmo
- Department of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, 12901 Bruce B. Downs Blvd. Tampa, FL 33612, USA
| | - Karim Nadra
- Department of Medical Genetics, University of Lausanne, 1005 Lausanne, Switzerland
| | - Roman Chrast
- Department of Medical Genetics, University of Lausanne, 1005 Lausanne, Switzerland
| | - Brian N. Finck
- Department of Medicine, Washington University School of Medicine, St.Louis, MO 63110, USA
| | - Min You
- Department of Molecular Pharmacology and Physiology, University of South Florida Health Sciences Center, 12901 Bruce B. Downs Blvd. Tampa, FL 33612, USA
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1016
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Shoda LKM, Woodhead JL, Siler SQ, Watkins PB, Howell BA. Linking physiology to toxicity using DILIsym®, a mechanistic mathematical model of drug-induced liver injury. Biopharm Drug Dispos 2013; 35:33-49. [DOI: 10.1002/bdd.1878] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 10/10/2013] [Accepted: 11/01/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Lisl K. M. Shoda
- The Hamner-UNC Institute for Drug Safety Sciences; The Hamner Institutes; Research Triangle Park NC 27709 USA
| | - Jeffrey L. Woodhead
- The Hamner-UNC Institute for Drug Safety Sciences; The Hamner Institutes; Research Triangle Park NC 27709 USA
| | - Scott Q. Siler
- The Hamner-UNC Institute for Drug Safety Sciences; The Hamner Institutes; Research Triangle Park NC 27709 USA
| | - Paul B. Watkins
- The Hamner-UNC Institute for Drug Safety Sciences; The Hamner Institutes; Research Triangle Park NC 27709 USA
| | - Brett A. Howell
- The Hamner-UNC Institute for Drug Safety Sciences; The Hamner Institutes; Research Triangle Park NC 27709 USA
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1017
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Olivera-Castillo L, Davalos A, Grant G, Valadez-Gonzalez N, Montero J, Barrera-Perez HAM, Chim-Chi Y, Olvera-Novoa MA, Ceja-Moreno V, Acereto-Escoffie P, Rubio-Piña J, Rodriguez-Canul R. Diets containing sea cucumber (Isostichopus badionotus) meals are hypocholesterolemic in young rats. PLoS One 2013; 8:e79446. [PMID: 24260223 PMCID: PMC3834158 DOI: 10.1371/journal.pone.0079446] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 09/22/2013] [Indexed: 12/25/2022] Open
Abstract
Sea cucumber is widely consumed as a putative functional food. It contains many biologically-active substances, but only limited research on its properties in vivo has been done. The effects of different meals containing Isostichopus badionotus, a sea cucumber from southeast Mexico, on growth performance and body lipid profile in young rats were analyzed. Sea cucumber body wall was either lyophilized, cooked (100 °C, 1 h in water) and lyophilized, or oven-dried (70 °C for 12 h). It was then ground and incorporated into cholesterol-containing diets. I. badionotus meals supported growth and improved lipid profile in rats. In particular, serum cholesterol, low density lipoproteins, triglycerides concentration and atherogenic index values were greatly reduced by some I. badionotus containing diets. Liver total lipids, triglycerides and cholesterol were also reduced. Cooking or heat-treatment of the meals lowered but did not abolish their hypolipidemic potency. Gene expression analysis of several key genes involved in cholesterol and lipid metabolism in liver showed that diets containing I. badionotus repressed the induction of key genes associated with dyslipidemia exerted by cholesterol supplementation. Consumption of I. badionotus from the Yucatan Peninsula is beneficial for dyslipidemia, although biological effect is clearly dependent on preparation method.
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Affiliation(s)
- Leticia Olivera-Castillo
- Centro de Investigacion y de Estudio Avanzados del Instituto Politecnico Nacional - Unidad Merida, Merida, Yucatan, Mexico
- * E-mail:
| | - Alberto Davalos
- Instituto Madrileño de Estudios Avanzados - Alimentación, Campus de Excelencia Internacional Universidad Autonoma de Madrid+Consejo Superior de Investigaciones Cientificas, Madrid, Spain
| | - George Grant
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, Scotland
| | - Nina Valadez-Gonzalez
- Centro de Investigaciones Regionales Dr. Hideyo Noguchi, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
| | - Jorge Montero
- Centro de Investigacion y de Estudio Avanzados del Instituto Politecnico Nacional - Unidad Merida, Merida, Yucatan, Mexico
| | | | - Yasser Chim-Chi
- Centro de Investigacion y de Estudio Avanzados del Instituto Politecnico Nacional - Unidad Merida, Merida, Yucatan, Mexico
| | - Miguel Angel Olvera-Novoa
- Centro de Investigacion y de Estudio Avanzados del Instituto Politecnico Nacional - Unidad Merida, Merida, Yucatan, Mexico
| | - Víctor Ceja-Moreno
- Centro de Investigacion y de Estudio Avanzados del Instituto Politecnico Nacional - Unidad Merida, Merida, Yucatan, Mexico
| | - Pablo Acereto-Escoffie
- Facultad de Ingenieria Quimica, Universidad Autonoma de Yucatan, Merida, Yucatan, Mexico
| | - Jorge Rubio-Piña
- Centro de Investigacion y de Estudio Avanzados del Instituto Politecnico Nacional - Unidad Merida, Merida, Yucatan, Mexico
| | - Rossanna Rodriguez-Canul
- Centro de Investigacion y de Estudio Avanzados del Instituto Politecnico Nacional - Unidad Merida, Merida, Yucatan, Mexico
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1018
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Abstract
Enterohepatic circulation is responsible for the capture of bile acids and other steroids produced or metabolized in the liver and secreted to the intestine, for reabsorption back into the circulation and transport back to the liver. Bile acids are secreted from the liver in the form of mixed micelles that also contain phosphatidylcholines and cholesterol that facilitate the uptake of fats and vitamins from the diet due to the surfactant properties of bile acids and lipids. Bile acids are synthesized in the liver from cholesterol by a cascade of enzymes that carry out oxidation and conjugation reactions, and transported to the bile duct and gall bladder where they are stored before being released into the intestine. Bile flow from the gall bladder to the small intestine is triggered by food intake in accordance with its role in lipid and vitamin absorption from the diet. Bile acids are further metabolized by gut bacteria and are transported back to the circulation. Metabolites produced in the liver are termed primary bile acids or primary conjugated bile salts, while the metabolites generated by bacterial are called secondary bile acids. About 95% of bile acids are reabsorbed in the proximal and distal ileum into the hepatic portal vein and then into the liver sinusoids, where they are efficiently transported into the liver with little remaining in circulation. Each bile acid is reabsorbed about 20 times on average before being eliminated. Enterohepatic circulation is under tight regulation by nuclear receptor signaling, notably by the farnesoid X receptor (FXR).
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Affiliation(s)
- Frank J Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA.
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1019
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Abstract
Bile acids are important physiological agents for intestinal nutrient absorption and biliary secretion of lipids, toxic metabolites, and xenobiotics. Bile acids also are signaling molecules and metabolic regulators that activate nuclear receptors and G protein-coupled receptor (GPCR) signaling to regulate hepatic lipid, glucose, and energy homeostasis and maintain metabolic homeostasis. Conversion of cholesterol to bile acids is critical for maintaining cholesterol homeostasis and preventing accumulation of cholesterol, triglycerides, and toxic metabolites, and injury in the liver and other organs. Enterohepatic circulation of bile acids from the liver to intestine and back to the liver plays a central role in nutrient absorption and distribution, and metabolic regulation and homeostasis. This physiological process is regulated by a complex membrane transport system in the liver and intestine regulated by nuclear receptors. Toxic bile acids may cause inflammation, apoptosis, and cell death. On the other hand, bile acid-activated nuclear and GPCR signaling protects against inflammation in liver, intestine, and macrophages. Disorders in bile acid metabolism cause cholestatic liver diseases, dyslipidemia, fatty liver diseases, cardiovascular diseases, and diabetes. Bile acids, bile acid derivatives, and bile acid sequestrants are therapeutic agents for treating chronic liver diseases, obesity, and diabetes in humans.
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1020
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Reshetnyak VI. Physiological and molecular biochemical mechanisms of bile formation. World J Gastroenterol 2013; 19:7341-7360. [PMID: 24259965 PMCID: PMC3831216 DOI: 10.3748/wjg.v19.i42.7341] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 07/17/2013] [Accepted: 09/29/2013] [Indexed: 02/06/2023] Open
Abstract
This review considers the physiological and molecular biochemical mechanisms of bile formation. The composition of bile and structure of a bile canaliculus, biosynthesis and conjugation of bile acids, bile phospholipids, formation of bile micellar structures, and enterohepatic circulation of bile acids are described. In general, the review focuses on the molecular physiology of the transporting systems of the hepatocyte sinusoidal and apical membranes. Knowledge of physiological and biochemical basis of bile formation has implications for understanding the mechanisms of development of pathological processes, associated with diseases of the liver and biliary tract.
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1021
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Pathak P, Li T, Chiang JYL. Retinoic acid-related orphan receptor α regulates diurnal rhythm and fasting induction of sterol 12α-hydroxylase in bile acid synthesis. J Biol Chem 2013; 288:37154-65. [PMID: 24226095 DOI: 10.1074/jbc.m113.485987] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Sterol 12α-hydroxylase (CYP8B1) is required for cholic acid synthesis and plays a critical role in intestinal cholesterol absorption and pathogenesis of cholesterol gallstone, dyslipidemia, and diabetes. In this study we investigated the underlying mechanism of fasting induction and circadian rhythm of CYP8B1 by a cholesterol-activated nuclear receptor and core clock gene retinoic acid-related orphan receptor α (RORα). Fasting stimulated, whereas restricted-feeding reduced expression of CYP8B1 mRNA and protein. However, fasting and feeding had little effect on the diurnal rhythm of RORα mRNA expression, but fasting increased RORα protein levels by cAMP-activated protein kinase A-mediated phosphorylation and stabilization of the protein. Adenovirus-mediated gene transduction of RORα to mice strongly induced CYP8B1 expression, and increased liver cholesterol and 12α-hydroxylated bile acids in the bile acid pool and serum. A reporter assay identified a functional RORα response element in the CYP8B1 promoter. RORα recruited cAMP response element-binding protein-binding protein (CBP) to stimulate histone acetylation on the CYP8B1 gene promoter. In conclusion, RORα is a key regulator of diurnal rhythm and fasting induction of CYP8B1, which regulates bile acid composition and serum and liver cholesterol levels. Antagonizing RORα activity may be a therapeutic strategy for treating inflammatory diseases such as non-alcoholic fatty liver disease and type 2 diabetes.
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Affiliation(s)
- Preeti Pathak
- From the Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio 44272 and
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1022
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Quintero P, Arrese M. Regulation of bile acid metabolism: new insights from inside. Hepatology 2013; 58:1850-3. [PMID: 23775943 DOI: 10.1002/hep.26569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 05/07/2013] [Accepted: 05/26/2013] [Indexed: 01/17/2023]
Affiliation(s)
- Pablo Quintero
- Departamento de Gastroenterología, Pontificia Universidad Católica de Chile, Santiago, Chile
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1023
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Romain G, Tremblay S, Arena ET, Antunes LCM, Covey S, Chow MT, Finlay BB, Menendez A. Enterohepatic bacterial infections dysregulate the FGF15-FGFR4 endocrine axis. BMC Microbiol 2013; 13:238. [PMID: 24165751 PMCID: PMC3818973 DOI: 10.1186/1471-2180-13-238] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 10/26/2013] [Indexed: 11/17/2022] Open
Abstract
Background Enterohepatic bacterial infections have the potential to affect multiple physiological processes of the body. Fibroblast growth factor 15/19 (FGF15 in mice, FGF19 in humans) is a hormone that functions as a central regulator of glucose, lipid and bile acid metabolism. FGF15/19 is produced in the intestine and exert its actions on the liver by signaling through the FGFR4-βKlotho receptor complex. Here, we examined the in vivo effects of enterohepatic bacterial infection over the FGF15 endocrine axis. Results Infection triggered significant reductions in the intestinal expression of Fgf15 and its hepatic receptor components (Fgfr4 and Klb (βKlotho)). Infection also resulted in alterations of the expression pattern of genes involved in hepatobiliary function, marked reduction in gallbladder bile volumes and accumulation of hepatic cholesterol and triglycerides. The decrease in ileal Fgf15 expression was associated with liver bacterial colonization and hepatobiliary pathophysiology rather than with direct intestinal bacterial pathogenesis. Conclusions Bacterial pathogens of the enterohepatic system can disturb the homeostasis of the FGF15/19-FGFR4 endocrine axis. These results open up a possible link between FGF15/19-FGFR4 disruptions and the metabolic and nutritional disorders observed in infectious diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Alfredo Menendez
- Department of Microbiology and Infectious Diseases, Faculty of Medicine and Health Sciences, University of Sherbrooke, Cancer Research Pavilion, Rm Z8-1072, 3201, rue Jean-Mignault, Sherbrooke, Québec J1E 4K8, Canada.
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1024
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Cui L, Meng Y, Xu D, Feng Y, Chen G, Hu B, Feng G, Yin L. Analysis of the metabolic properties of maintenance hemodialysis patients with glucose-added dialysis based on high performance liquid chromatography quadrupole time-of-flight mass spectrometry. Ther Clin Risk Manag 2013; 9:417-25. [PMID: 24194643 PMCID: PMC3814896 DOI: 10.2147/tcrm.s49634] [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: 11/30/2022] Open
Abstract
The purpose of this study was to compare the metabolic properties of maintenance hemodialysis patients treated with glucose-containing and glucose-free dialysate using metabonomics. Pre- and post-dialysis serum samples from group G (-) using glucose-free dialysate, and group G (+) using glucose-added dialysate (glucose levels were 5.5 mmol/L) were analyzed and tested with high performance liquid chromatography quadrupole time-of-flight mass spectrometry. Orthogonal signal correction-partial least squares discriminate analysis revealed a significant difference in the post-dialysis metabolic properties between samples from the G (-) and G (+) groups, and concentrations of leucine and dihydroxyprostaglandin F2α were higher in the G (+) group than in the G (-) group. However, markers of reactive lipid mobilization and amino acid release, such as bile acids, aspartate, and valine, were lower in the G (+) group than in the G (-) group. There were no significant differences in excitatory neurotransmitters aspartate and phosphorylated anandamide. Use of liquid chromatography-tandem mass spectrometry metabonomics indicated that using glucose-added dialysate was superior to glucose-free dialysate in the protection of the central nervous system of maintenance hemodialysis patients, but had potential risks in stimulating oxidative stress.
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Affiliation(s)
- Li Cui
- Xi’xiang People’s Hospital Affiliated to Guangdong Medical College, Shenzhen, People’s Republic of China
| | - Yu Meng
- Nephrology Department of the First Hospital Affiliated to Ji’nan University, Guangzhou, People’s Republic of China
| | - Dan Xu
- Nephrology Department of the First Hospital Affiliated to Ji’nan University, Guangzhou, People’s Republic of China
| | - Yanyan Feng
- Nephrology Department of the First Hospital Affiliated to Ji’nan University, Guangzhou, People’s Republic of China
| | - Gangyi Chen
- First Hospital of Guangzhou University of Chinese Medicine, People’s Republic of China
| | - Bo Hu
- Nephrology Department of the First Hospital Affiliated to Ji’nan University, Guangzhou, People’s Republic of China
| | - Guijuan Feng
- Assisted Reproductive Centre of the First Hospital Affiliated to Ji’nan University, Guangzhou, People’s Republic of China
| | - Lianghong Yin
- Nephrology Department of the First Hospital Affiliated to Ji’nan University, Guangzhou, People’s Republic of China
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1025
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Pfeifer ND, Hardwick RN, Brouwer KLR. Role of hepatic efflux transporters in regulating systemic and hepatocyte exposure to xenobiotics. Annu Rev Pharmacol Toxicol 2013; 54:509-35. [PMID: 24160696 DOI: 10.1146/annurev-pharmtox-011613-140021] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hepatic efflux transporters include numerous well-known and emerging proteins localized to the canalicular or basolateral membrane of the hepatocyte that are responsible for the excretion of drugs into the bile or blood, respectively. Altered function of hepatic efflux transporters due to drug-drug interactions, genetic variation, and/or disease states may lead to changes in xenobiotic exposure in the hepatocyte and/or systemic circulation. This review focuses on transport proteins involved in the hepatocellular efflux of drugs and metabolites, discusses mechanisms of altered transporter function as well as the interplay between multiple transport pathways, and highlights the importance of considering intracellular unbound concentrations of transporter substrates and/or inhibitors. Methods to evaluate hepatic efflux transport and predict the effects of impaired transporter function on systemic and hepatocyte exposure are discussed, and the sandwich-cultured hepatocyte model to evaluate comprehensively the role of hepatic efflux in the hepatobiliary disposition of xenobiotics is characterized.
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Affiliation(s)
- Nathan D Pfeifer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599; ,
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1026
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Marcelin G, Jo YH, Li X, Schwartz GJ, Zhang Y, Dun NJ, Lyu RM, Blouet C, Chang JK, Chua S. Central action of FGF19 reduces hypothalamic AGRP/NPY neuron activity and improves glucose metabolism. Mol Metab 2013; 3:19-28. [PMID: 24567901 PMCID: PMC3929918 DOI: 10.1016/j.molmet.2013.10.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/11/2013] [Accepted: 10/14/2013] [Indexed: 12/23/2022] Open
Abstract
Tight control of glucose excursions has been a long-standing goal of treatment for patients with type 2 diabetes mellitus in order to ameliorate the morbidity and mortality associated with hyperglycemia. Fibroblast growth factor (FGF) 19 is a hormone-like enterokine released postprandially that emerged as a potential therapeutic agent for metabolic disorders, including diabetes and obesity. Remarkably, FGF19 treatment has hypoglycemic actions that remain potent in models of genetic and acquired insulin resistance. Here, we provided evidence that the central nervous system responds to FGF19 administered in the periphery. Then, in two mouse models of insulin resistance, leptin-deficiency and high-fat diet feeding, third intra-cerebro-ventricular infusions of FGF19 improved glycemic status, reduced insulin resistance and potentiated insulin signaling in the periphery. In addition, our study highlights a new mechanism of central FGF19 action, involving the suppression of AGRP/NPY neuronal activity. Overall, our work unveils novel regulatory pathways induced by FGF19 that will be useful in the design of novel strategies to control diabetes in obesity.
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Affiliation(s)
- Geneviève Marcelin
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Young-Hwan Jo
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Xiaosong Li
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Gary J Schwartz
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Ying Zhang
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19122, USA ; Department of Pathophysiology, Kunming Medical University, Kunming, PR China
| | - Nae J Dun
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19122, USA
| | - Rong-Ming Lyu
- Phoenix Pharmaceuticals, Inc., Burlingame, CA 94010, USA
| | - Clémence Blouet
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jaw K Chang
- Phoenix Pharmaceuticals, Inc., Burlingame, CA 94010, USA
| | - Streamson Chua
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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1027
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Meguro S, Hasumura T, Hase T. Coffee polyphenols exert hypocholesterolemic effects in zebrafish fed a high-cholesterol diet. Nutr Metab (Lond) 2013; 10:61. [PMID: 24220226 PMCID: PMC3871761 DOI: 10.1186/1743-7075-10-61] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 09/26/2013] [Indexed: 11/29/2022] Open
Abstract
Background Hypercholesterolemia is an important risk factor for the development of coronary artery disease. Some dietary polyphenols, such as coffee polyphenols (CPPs), reduce cholesterol levels. The mechanism of this cholesterol-lowering effect is not fully understood, although 5-CQA, a major component of CPPs, reportedly inhibits cholesterol biosynthesis. Here, we investigated the mechanism of the cholesterol-lowering effect of CPPs on the basis of cholesterol metabolism–related gene expression in the liver. We also examined the effects of CPPs on vascular lipid accumulation in zebrafish with high cholesterol diet–induced hypercholesterolemia. Methods Over 14 weeks, adult zebrafish were fed a control diet, a high-cholesterol diet, or the latter diet supplemented with CPPs. To measure the extent of vascular lipid accumulation, for 10 days larval zebrafish (which are optically transparent) were fed these same diets with the addition of a fluorescent cholesteryl ester. Results In adult zebrafish, addition of CPPs to a high-cholesterol diet significantly suppressed the increase in plasma and liver cholesterol levels seen when fish ingested the same diet lacking CPPs. Transcription levels of the liver genes hmgcra (encoding 3-hydroxy-3-methylglutaryl-coenzyme A reductase A, a rate-limiting enzyme in cholesterol biosynthesis) and mtp (encoding microsomal triglyceride transfer protein, a lipid transfer protein required for assembly and secretion of lipoproteins) were significantly lower in fish fed the CPP-containing diet than in fish fed the unsupplemented high-cholesterol diet. In contrast, the expression level of the liver gene cyp7a1a (encoding the cytochrome P450 polypeptide 1a of subfamily A of family 7, a rate-limiting enzyme for bile acid biosynthesis) increased significantly upon consumption of the CPP-containing diet. In larval fish, accumulation of fluorescently labeled cholesterol in the caudal artery was greatly reduced on the CPP-containing diet. Conclusions CPP ingestion suppressed cholesterol accumulation in the plasma, liver, and vascular system of zebrafish. Downregulation of cholesterol and lipoprotein synthesis and upregulation of bile acid synthesis in the liver may be the fundamental underlying mechanisms by which CPPs exert their hypocholesterolemic effects. CPP intake may help prevent and manage hypercholesterolemia in humans, and further investigations along these lines using a variety of CPP dose rates are warranted.
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1028
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Murashita K, Yoshiura Y, Chisada SI, Furuita H, Sugita T, Matsunari H, Yamamoto T. Postprandial response and tissue distribution of the bile acid synthesis-related genes, cyp7a1, cyp8b1 and shp, in rainbow trout Oncorhynchus mykiss. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:361-9. [DOI: 10.1016/j.cbpa.2013.07.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 07/09/2013] [Accepted: 07/09/2013] [Indexed: 01/09/2023]
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1029
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Inamine T, Higa S, Noguchi F, Kondo S, Omagari K, Yatsuhashi H, Tsukamoto K, Nakamura M. Association of genes involved in bile acid synthesis with the progression of primary biliary cirrhosis in Japanese patients. J Gastroenterol 2013; 48:1160-70. [PMID: 23354620 DOI: 10.1007/s00535-012-0730-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 11/26/2012] [Indexed: 02/04/2023]
Abstract
BACKGROUND Patients with primary biliary cirrhosis (PBC) exhibit a variety of clinical manifestations and patterns of disease progression. The aim of this study was to identify genetic determinants of PBC progression. METHODS A total of 52 tag single nucleotide polymorphisms (SNPs) of 11 candidate genes involved in regulating bile acid synthesis were analyzed by polymerase chain reaction (PCR)-restriction fragment length polymorphism, -high resolution melting curve analysis, or -direct DNA sequencing in 315 Japanese patients with PBC. RESULTS In this study, four tag SNPs of CYP7A1 (rs1457043, rs8192870, rs3808607, and rs3824260), two tag SNPs of HNF4A (rs6017340 and 6031587), and one SNP of PPARGC1A (rs8192678) showed a significant association with PBC progression. In addition, a dual luciferase assay revealed that the polymorphism of rs3808607 in CYP7A1 altered the expression of CYP7A1 in HepG2. Specifically, the CYP7A1 promoter carrying the risk G allele for PBC progression induced higher expression of CYP7A1 under both the normal and cholestatic conditions in vitro as compared to another promoter carrying the non-risk T allele. CONCLUSION These results suggested that the genetic variants of CYP7A1 and its transcriptional activators (HNF4A and PPARGC1A) may activate bile acid synthesis, resulting in the accumulation of bile acids in hepatocytes and eventually leading to the predisposition to PBC progression. Thus, the regulation of CYP7A1 expression may represent an attractive therapeutic target for cholestatic liver diseases including PBC.
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Affiliation(s)
- Tatsuo Inamine
- Department of Pharmacotherapeutics, Nagasaki University Graduate School of Biomedical Sciences, 1-14 Bunkyo-machi, Nagasaki, 852-8521, Japan
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1030
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High-throughput bioanalysis of bile acids and their conjugates using UHPLC coupled to HRMS. Bioanalysis 2013; 5:2481-94. [DOI: 10.4155/bio.13.215] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Background: Quantitative assessment of bile acids in biological matrixes is of growing interest, primarily due to hepatic toxicity resulting from drug interactions with the bile salt export pump. Nevertheless, many bile acids demonstrate poor fragmentation in MS, making conventional MS/MS not a good match for their selective quantitation in biological matrices. Results: The current study was designed to evaluate the feasibility of simultaneous quantitation of 19 bile acids using HRMS coupled to UHPLC separation with minimal instrument optimization. An effective chromatography was developed using an Agilent Zorbax® Eclipse XDB-C18 column (1.8 µm, 50 x 2.1 mm internal diameter), achieving separation of 19 compounds in 10 min. Excellent assay reproducibility was demonstrated, with two sets of standard curves, run 42 days apart. Conclusions: The results show that LC–HRMS is a viable platform for high throughput bioanalysis of bile acids especially in a drug-discovery setting.
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1031
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Pfeifer ND, Bridges AS, Ferslew BC, Hardwick RN, Brouwer KLR. Hepatic basolateral efflux contributes significantly to rosuvastatin disposition II: characterization of hepatic elimination by basolateral, biliary, and metabolic clearance pathways in rat isolated perfused liver. J Pharmacol Exp Ther 2013; 347:737-45. [PMID: 24080682 DOI: 10.1124/jpet.113.208314] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Basolateral efflux clearance (CLBL) contributes significantly to rosuvastatin (RSV) elimination in sandwich-cultured hepatocytes (SCH). The contribution of CLBL to RSV hepatic elimination was determined in single-pass isolated perfused livers (IPLs) from wild-type (WT) and multidrug resistance-associated protein 2 (Mrp2)-deficient (TR(-)) rats in the absence and presence of the P-glycoprotein and breast cancer resistance protein (Bcrp) inhibitor, elacridar (GF120918); clearance values were compared with SCH. RSV biliary clearance (CLBile) was ablated almost completely by GF120918 in TR(-) IPLs, confirming that Mrp2 and Bcrp primarily are responsible for RSV CLBile. RSV appearance in outflow perfusate was attributed primarily to CLBL, which was impaired in TR(-) IPLs. CLBL was ≈ 6-fold greater than CLBile in the linear range in WT IPLs in the absence of GF120918. Recovery of unchanged RSV in liver tissue increased in TR(-) compared with WT (≈ 25 versus 6% of the administered dose) due to impaired CLBL and CLBile. RSV pentanoic acid, identified by high-resolution liquid chromatography-tandem mass spectroscopy, comprised ≈ 40% of total liver content and ≈ 16% of the administered dose in TR(-) livers at the end of perfusion, compared with ≈ 30 and 3% in WT livers, consistent with impaired RSV excretion and "shunting" to the metabolic pathway. In vitro-ex vivo extrapolation between WT SCH and IPLs (without GF120918) revealed that uptake clearance and CLBL were 4.2- and 6.4-fold lower, respectively, in rat SCH compared with IPLs; CLBile translated almost directly (1.1-fold). The present IPL data confirmed the significant role of CLBL in RSV hepatic elimination, and demonstrated that both CLBL and CLBile influence RSV hepatic and systemic exposure.
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Affiliation(s)
- Nathan D Pfeifer
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, Chapel Hill, North Carolina (N.D.P., B.C.F., K.L.R.B.); and Department of Pathology (A.S.B.) and Curriculum in Toxicology (R.N.H., K.L.R.B.), School of Medicine, UNC School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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1032
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Liu JL, Hekimi S. The impact of mitochondrial oxidative stress on bile acid-like molecules in C. elegans provides a new perspective on human metabolic diseases. WORM 2013; 2:e21457. [PMID: 24058856 PMCID: PMC3670457 DOI: 10.4161/worm.21457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 07/11/2012] [Indexed: 12/19/2022]
Abstract
C. elegans is a model used to study cholesterol metabolism and the functions of its metabolites. Several studies have reported that, in worms, cholesterol is not a structural component of the membrane as it is in vertebrates. However, as in other animals, it is used for the synthesis of steroid hormones that regulate physiological processes such as dauer formation, molting and defecation. After cholesterol is taken up by the gut, mechanisms of transport of cholesterol between tissues in C. elegans involve lipoproteins, as in mammals. A recent study shows that both cholesterol uptake and lipoprotein metabolism in C. elegans are regulated by molecules whose activities, biosynthesis, and secretion strongly resemble those of mammalian bile acids, which are metabolites of cholesterol that act on metabolism in a variety of ways. Importantly, it was found that oxidative stress upsets the regulation of the synthesis of these molecules. Given the known function of mammalian bile acids as metabolic regulators of lipid and glucose homeostasis, future investigations of the biology of C. elegans bile acid-like molecules could provide information on the etiology of human metabolic disorders that are characterized by elevated oxidative stress.
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Affiliation(s)
- Ju-Ling Liu
- Department of Biology; McGill University; Montreal, Québec, Canada
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1033
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Role of bile acids in liver injury and regeneration following acetaminophen overdose. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:1518-1526. [PMID: 24007882 DOI: 10.1016/j.ajpath.2013.07.012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 06/24/2013] [Accepted: 07/18/2013] [Indexed: 02/06/2023]
Abstract
Bile acids play a critical role in liver injury and regeneration, but their role in acetaminophen (APAP)-induced liver injury is not known. We tested the effect of bile acid modulation on APAP hepatotoxicity using C57BL/6 mice, which were fed a normal diet, a 2% cholestyramine (CSA)-containing diet for bile acid depletion, or a 0.2% cholic acid (CA)-containing diet for 1 week before treatment with 400 mg/kg APAP. CSA-mediated bile acid depletion resulted in significantly higher liver injury and delayed regeneration after APAP treatment. In contrast, 0.2% CA supplementation in the diet resulted in a moderate delay in progression of liver injury and significantly higher liver regeneration after APAP treatment. Either CSA-mediated bile acid depletion or CA supplementation did not affect hepatic CYP2E1 levels or glutathione depletion after APAP treatment. CSA-fed mice exhibited significantly higher activation of c-Jun N-terminal protein kinases and a significant decrease in intestinal fibroblast growth factor 15 mRNA after APAP treatment. In contrast, mice fed a 0.2% CA diet had significantly lower c-Jun N-terminal protein kinase activation and 12-fold higher fibroblast growth factor 15 mRNA in the intestines. Liver regeneration after APAP treatment was significantly faster in CA diet-fed mice after APAP administration secondary to rapid cyclin D1 induction. Taken together, these data indicate that bile acids play a critical role in both initiation and recovery of APAP-induced liver injury.
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1034
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YANG KYUNGHEE, KÖCK KATHLEEN, SEDYKH ALEXANDER, TROPSHA ALEXANDER, BROUWER KIML. An updated review on drug-induced cholestasis: mechanisms and investigation of physicochemical properties and pharmacokinetic parameters. J Pharm Sci 2013; 102:3037-57. [PMID: 23653385 PMCID: PMC4369767 DOI: 10.1002/jps.23584] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 04/13/2013] [Accepted: 04/16/2013] [Indexed: 12/15/2022]
Abstract
Drug-induced cholestasis is an important form of acquired liver disease and is associated with significant morbidity and mortality. Bile acids are key signaling molecules, but they can exert toxic responses when they accumulate in hepatocytes. This review focuses on the physiological mechanisms of drug-induced cholestasis associated with altered bile acid homeostasis due to direct (e.g., bile acid transporter inhibition) or indirect (e.g., activation of nuclear receptors, altered function/expression of bile acid transporters) processes. Mechanistic information about the effects of a drug on bile acid homeostasis is important when evaluating the cholestatic potential of a compound, but experimental data often are not available. The relationship between physicochemical properties, pharmacokinetic parameters, and inhibition of the bile salt export pump among 77 cholestatic drugs with different pathophysiological mechanisms of cholestasis (i.e., impaired formation of bile vs. physical obstruction of bile flow) was investigated. The utility of in silico models to obtain mechanistic information about the impact of compounds on bile acid homeostasis to aid in predicting the cholestatic potential of drugs is highlighted.
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Affiliation(s)
- KYUNGHEE YANG
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - KATHLEEN KÖCK
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - ALEXANDER SEDYKH
- Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - ALEXANDER TROPSHA
- Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - KIM L.R. BROUWER
- Division of Pharmacotherapy and Experimental Therapeutics, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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1035
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Li T, Francl JM, Boehme S, Chiang JYL. Regulation of cholesterol and bile acid homeostasis by the cholesterol 7α-hydroxylase/steroid response element-binding protein 2/microRNA-33a axis in mice. Hepatology 2013; 58:1111-21. [PMID: 23536474 PMCID: PMC3735649 DOI: 10.1002/hep.26427] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Accepted: 03/25/2013] [Indexed: 12/11/2022]
Abstract
UNLABELLED Bile acid synthesis not only produces physiological detergents required for intestinal nutrient absorption, but also plays a critical role in regulating hepatic and whole-body metabolic homeostasis. We recently reported that overexpression of cholesterol 7α-hydroxylase (CYP7A1) in the liver resulted in improved metabolic homeostasis in Cyp7a1 transgenic (Cyp7a1-tg) mice. This study further investigated the molecular links between bile acid metabolism and lipid homeostasis. Microarray gene profiling revealed that CYP7A1 overexpression led to marked activation of the steroid response element-binding protein 2 (SREBP2)-regulated cholesterol metabolic network and absence of bile acid repression of lipogenic gene expression in livers of Cyp7a1-tg mice. Interestingly, Cyp7a1-tg mice showed significantly elevated hepatic cholesterol synthesis rates, but reduced hepatic fatty acid synthesis rates, which was accompanied by increased (14) C-glucose-derived acetyl-coenzyme A incorporation into sterols for fecal excretion. Induction of SREBP2 also coinduces intronic microRNA-33a (miR-33a) in the SREBP2 gene in Cyp7a1-tg mice. Overexpression of miR-33a in the liver resulted in decreased bile acid pool, increased hepatic cholesterol content, and lowered serum cholesterol in mice. CONCLUSION This study suggests that a CYP7A1/SREBP2/miR-33a axis plays a critical role in regulation of hepatic cholesterol, bile acid, and fatty acid synthesis. Antagonism of miR-33a may be a potential strategy to increase bile acid synthesis to maintain lipid homeostasis and prevent nonalcoholic fatty liver disease, diabetes, and obesity.
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Affiliation(s)
- Tiangang Li
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH 44272,Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160
| | - Jessica M. Francl
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH 44272
| | - Shannon Boehme
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH 44272
| | - John Y. L. Chiang
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH 44272,Corresponding address: John Chiang, Ph.D., Department of Integrative Medical Sciences, Northeast Ohio Medical University, 4209 State Route 44, Rootstown, OH 44272; Phone: 330-325-6694; Fax: 330-325-5910;
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1036
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Ridlon JM, Alves JM, Hylemon PB, Bajaj JS. Cirrhosis, bile acids and gut microbiota: unraveling a complex relationship. Gut Microbes 2013; 4:382-7. [PMID: 23851335 PMCID: PMC3839982 DOI: 10.4161/gmic.25723] [Citation(s) in RCA: 253] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A picture is now starting to emerge regarding the liver-bile acid-microbiome axis. Increasing levels of the primary bile acid cholic acid (CA) causes a dramatic shift toward the Firmicutes, particularly Clostridium cluster XIVa and increasing production of the harmful secondary bile acid deoxycholic acid (DCA). During progression of cirrhosis, the microbiome, both through their metabolism, cell wall components (LPS) and translocation lead to inflammation. Inflammation suppresses synthesis of bile acids in the liver leading to a positive-feedback mechanism. Decrease in bile acids entering the intestines appears to favor overgrowth of pathogenic and pro-inflammatory members of the microbiome including Porphyromonadaceae and Enterobacteriaceae. Decreasing bile acid concentration in the colon in cirrhosis is also associated with decreases in Clostridium cluster XIVa, which includes bile acid 7α-dehydroxylating bacteria which produce DCA. Rifaximin treatment appears to act by suppressing DCA production, reducing endotoxemia and harmful metabolites without significantly altering microbiome structure. Taken together, the bile acid pool size and composition appear to be a major regulator of microbiome structure, which in turn appears to be an important regulator of bile acid pool size and composition. The balance between this equilibrium is critical for human health and disease.
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Affiliation(s)
- Jason M Ridlon
- Department of Microbiology and Immunology; Virginia Commonwealth University; Richmond, VA USA,McGuire VA Medical Center; Richmond, VA USA
| | - Joao Marcelo Alves
- Department of Microbiology and Immunology; Virginia Commonwealth University; Richmond, VA USA
| | - Phillip B Hylemon
- Department of Microbiology and Immunology; Virginia Commonwealth University; Richmond, VA USA,McGuire VA Medical Center; Richmond, VA USA
| | - Jasmohan S Bajaj
- McGuire VA Medical Center; Richmond, VA USA,Division of Gastroenterology, Hepatology and Nutrition; Virginia Commonwealth University; Richmond, VA USA,Correspondence to: Jasmohan S Bajaj,
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1037
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Zhu QN, Xie HM, Zhang D, Liu J, Lu YF. Hepatic bile acids and bile acid-related gene expression in pregnant and lactating rats. PeerJ 2013; 1:e143. [PMID: 24010021 PMCID: PMC3757468 DOI: 10.7717/peerj.143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 08/05/2013] [Indexed: 01/28/2023] Open
Abstract
Background. Significant physiological changes occur during pregnancy and lactation. Intrahepatic cholestasis of pregnancy (ICP) is a liver disease closely related to disruption of bile acid homeostasis. The objective of this study was to examine the regulation of bile acid synthesis and transport in normal pregnant and lactating rats. Materials and Methods. Livers from timed pregnant SD rats were collected on gestational days (GD) 10, 14 and 19, and postnatal days (PND) 1, 7, 14 and 21. Total bile acids were determined by the enzymatic method, total RNA was isolated and subjected to real time RT-PCR analysis. Liver protein was extracted for western-blot analysis. Results. Under physiological conditions hepatic bile acids were not elevated during pregnancy but increased during lactation in rats. Bile acid synthesis rate-limiting enzyme Cyp7a1 was unchanged on gestational days, but increased on PND14 and 21 at mRNA and protein levels. Expression of Cyp8b1, Cyp27a1 and Cyp7b1 was also higher during lactation. The mRNA levels of small heterodimer partner (SHP) and protein levels of farnesoid X receptor (FXR) were increased during pregnancy and lactation. Bile acid transporters Ntcp, Bsep, Mrp3 and Mrp4 were lower at gestation, but increased during lactation. Hepatic Oatp transporters were decreased during pregnancy and lactation. Conclusion. Hepatic bile acid homeostasis is maintained during normal pregnancy in rats, probably through the FXR-SHP regulation. The expression of bile acid synthesis genes and liver bile acid accumulation were increased during lactation, together with increased expression of bile acid efflux transporter Bsep, Mrp3 and Mrp4.
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Affiliation(s)
- Qiong N Zhu
- Department of Pharmacology and Key Lab of Basic Pharmacology of Guizhou, Zunyi Medical College , Zunyi , China
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1038
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Xie G, Zhang S, Zheng X, Jia W. Metabolomics approaches for characterizing metabolic interactions between host and its commensal microbes. Electrophoresis 2013; 34:2787-98. [PMID: 23775228 DOI: 10.1002/elps.201300017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 05/14/2013] [Accepted: 05/15/2013] [Indexed: 02/06/2023]
Abstract
It is increasingly evident that the gut microbiota is involved in the regulation of multiple mammalian metabolic pathways through a series of interactive host-microbiota metabolic, signaling, and immune-inflammatory axes that physiologically connect the gut, liver, brain, and other organs. Correlation of the metabotypes with the gut microbial profiles derived from culture-independent molecular techniques is increasingly useful for deciphering inherent and intimate host-microbe relationships. Real-time analysis of the small molecule metabolites derived from gut microbial-host co-metabolism is essential for understanding the metabolic functions of the gut microbiome and has tremendous implications for personalized healthcare strategies. Metabolomics, an array of analytical techniques that includes high resolution NMR spectroscopy and chromatography-MS in conjunction with chemometrics and bioinformatics tools, enables characterization of the metabolic footprints of mammalian hosts that correlate with the microbial community in the intestinal tract. The metabolomics approach provides important information of a complete spectrum of metabolites produced from the gut microbial-mammalian co-metabolism and is improving our understanding of the molecular mechanisms underlying multilevel host-microbe interactions. In this review, the interactions of gut microbiota with their host are discussed and some examples of NMR- or MS-based metabolomics applications for characterizing the metabolic footprints of gut microbial-host co-metabolism are described. Advances in the metabolomic analysis of bile acids, short-chain fatty acids, and choline metabolism are also summarized.
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Affiliation(s)
- Guoxiang Xie
- Center for Translational Medicine, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, China; Center for Translational Biomedical Research, University of North Carolina at Greensboro, North Carolina Research Campus, Kannapolis, North Carolina, USA; University of Hawaii Cancer Center, Honolulu, Hawaii, USA
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1039
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Liu J, Lu YF, Zhang Y, Wu KC, Fan F, Klaassen CD. Oleanolic acid alters bile acid metabolism and produces cholestatic liver injury in mice. Toxicol Appl Pharmacol 2013; 272:816-24. [PMID: 23948738 DOI: 10.1016/j.taap.2013.08.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 07/31/2013] [Accepted: 08/02/2013] [Indexed: 12/11/2022]
Abstract
Oleanolic acid (OA) is a triterpenoids that exists widely in plants. OA is effective in protecting against hepatotoxicants. Whereas a low dose of OA is hepatoprotective, higher doses and longer-term use of OA produce liver injury. This study characterized OA-induced liver injury in mice. Adult C57BL/6 mice were given OA at doses of 0, 22.5, 45, 90, and 135 mg/kg, s.c., daily for 5 days, and liver injury was observed at doses of 90 mg/kg and above, as evidenced by increases in serum activities of alanine aminotransferase and alkaline phosphatase, increases in serum total bilirubin, as well as by liver histopathology. OA-induced cholestatic liver injury was further evidenced by marked increases of both unconjugated and conjugated bile acids (BAs) in serum. Gene and protein expression analysis suggested that livers of OA-treated mice had adaptive responses to prevent BA accumulation by suppressing BA biosynthetic enzyme genes (Cyp7a1, 8b1, 27a1, and 7b1); lowering BA uptake transporters (Ntcp and Oatp1b2); and increasing a BA efflux transporter (Ostβ). OA increased the expression of Nrf2 and its target gene, Nqo1, but decreased the expression of AhR, CAR and PPARα along with their target genes, Cyp1a2, Cyp2b10 and Cyp4a10. OA had minimal effects on PXR and Cyp3a11. Taken together, the present study characterized OA-induced liver injury, which is associated with altered BA homeostasis, and alerts its toxicity potential.
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Affiliation(s)
- Jie Liu
- University of Kansas Medical Center, Kansas City, KS 66160, USA; Zunyi Medical College, Zunyi 563003, China.
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1040
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Seok S, Kanamaluru D, Xiao Z, Ryerson D, Choi SE, Suino-Powell K, Xu HE, Veenstra TD, Kemper JK. Bile acid signal-induced phosphorylation of small heterodimer partner by protein kinase Cζ is critical for epigenomic regulation of liver metabolic genes. J Biol Chem 2013; 288:23252-63. [PMID: 23824184 PMCID: PMC3743497 DOI: 10.1074/jbc.m113.452037] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 07/01/2013] [Indexed: 12/12/2022] Open
Abstract
Bile acids (BAs) are recently recognized key signaling molecules that control integrative metabolism and energy expenditure. BAs activate multiple signaling pathways, including those of nuclear receptors, primarily farnesoid X receptor (FXR), membrane BA receptors, and FXR-induced FGF19 to regulate the fed-state metabolism. Small heterodimer partner (SHP) has been implicated as a key mediator of these BA signaling pathways by recruitment of chromatin modifying proteins, but the key question of how SHP transduces BA signaling into repressive histone modifications at liver metabolic genes remains unknown. Here we show that protein kinase Cζ (PKCζ) is activated by BA or FGF19 and phosphorylates SHP at Thr-55 and that Thr-55 phosphorylation is critical for the epigenomic coordinator functions of SHP. PKCζ is coimmunopreciptitated with SHP and both are recruited to SHP target genes after bile acid or FGF19 treatment. Activated phosphorylated PKCζ and phosphorylated SHP are predominantly located in the nucleus after FGF19 treatment. Phosphorylation at Thr-55 is required for subsequent methylation at Arg-57, a naturally occurring mutation site in metabolic syndrome patients. Thr-55 phosphorylation increases interaction of SHP with chromatin modifiers and their occupancy at selective BA-responsive genes. This molecular cascade leads to repressive modifications of histones at metabolic target genes, and consequently, decreased BA pools and hepatic triglyceride levels. Remarkably, mutation of Thr-55 attenuates these SHP-mediated epigenomic and metabolic effects. This study identifies PKCζ as a novel key upstream regulator of BA-regulated SHP function, revealing the role of Thr-55 phosphorylation in epigenomic regulation of liver metabolism.
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Affiliation(s)
- Sunmi Seok
- From the Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Deepthi Kanamaluru
- From the Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Zhen Xiao
- the Laboratory of Proteomics and Analytical Technologies, Advanced Technology Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, and
| | - Daniel Ryerson
- From the Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Sung-E Choi
- From the Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Kelly Suino-Powell
- the Laboratory of Structure Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - H. Eric Xu
- the Laboratory of Structure Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503
| | - Timothy D. Veenstra
- the Laboratory of Proteomics and Analytical Technologies, Advanced Technology Program, SAIC-Frederick, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, and
| | - Jongsook Kim Kemper
- From the Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
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1041
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Lu YF, Jin T, Xu Y, Zhang D, Wu Q, Zhang YKJ, Liu J. Sex differences in the circadian variation of cytochrome p450 genes and corresponding nuclear receptors in mouse liver. Chronobiol Int 2013; 30:1135-43. [PMID: 23926955 DOI: 10.3109/07420528.2013.805762] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Sex differences and circadian variation are two major factors that affect the expression of drug-processing genes. This study aimed to examine sex differences in the circadian variation of hepatic cytochrome P450 (Cyp) genes and corresponding nuclear receptors. Adult mice were acclimated to environmentally controlled facilities for 2 wks, and livers were collected every 4 h during a 24-h period. Total RNA and protein were isolated and subjected to real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot analysis. The mRNA expression of the aryl hydrocarbon receptor (AhR) and AhR-regulated Cyp1a1 and Cyp1a2 were higher in females and higher during the light phase. The mRNA expression of constitutive and rostane receptor (CAR) and CYP2B10 protein was female-predominant and higher in the dark phase. Pregnane X receptor (PXR) peaked around 18:00 h, but PXR-regulated Cyp3a11 and Cyp3a25 were higher at 10:00 h, without apparent sex dimorphism at protein levels. Peroxisome proliferator-activated receptor-α (PPARα), Cyp4a10, and Cyp4a14 were higher in females and peaked between 14:00 and 18:00 h. The mRNA levels of farnesoid X receptor (FXR), Cyp7a1, and Cyp27a1 peaked around 18:00 h and CYP7A1 protein was higher during the dark phase and higher in females. Cyp7b1(male-predominant) and Cyp2a4 (female-predominant) both showed circadian variation. Circadian variation of hepatic clock genes such as nuclear receptor Rev-erbα, cryptochrome 1 (Cry1), and brain muscle ARNT-like protein 1 (Bmal1) showed distinct patterns. Sex differences and circadian rhythmicity of Cyp genes and corresponding nuclear receptors exist in mouse liver that could impact xenobiotic metabolism and toxicity at different times of the day.
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Affiliation(s)
- Yuan-Fu Lu
- Key Laboratory of Basic Pharmacology of Guizhou, Zunyi Medical College , Zunyi , China
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1042
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Selkälä EM, Kuusisto SM, Salonurmi T, Savolainen MJ, Jauhiainen M, Pirilä PL, Kvist AP, Conzelmann E, Schmitz W, Alexson SE, Kotti TJ, Hiltunen JK, Autio KJ. Metabolic adaptation allows Amacr-deficient mice to remain symptom-free despite low levels of mature bile acids. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1831:1335-43. [DOI: 10.1016/j.bbalip.2013.05.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/30/2013] [Accepted: 05/06/2013] [Indexed: 10/26/2022]
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1043
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D'Amato M. Genes and functional GI disorders: from casual to causal relationship. Neurogastroenterol Motil 2013; 25:638-49. [PMID: 23826979 DOI: 10.1111/nmo.12173] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Accepted: 05/24/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND The functional gastrointestinal disorders (FGID), and in particular irritable bowel syndrome (IBS), pose a considerable burden on health care and society, and negatively impact quality of life. These are common conditions of unknown etiology, and symptom-based criteria are currently the sole nosological tools for their clinical classification. Major insight into FGID pathophysiology is therefore needed and, in recent years, increasing hope has been put on genetic research for the identification of causative pathways. This is more advanced in IBS compared with other FGID, but it has still provided often indecipherable results and no unequivocal evidence of a pathogenetic role for any particular gene. Although thousands of genetic variants have been undoubtedly linked to human disease in hundreds of genome-wide association studies (GWAS), no similar effort has yet even been attempted in FGID. If meaningful, robust, and reproducible results are to be obtained for IBS and other FGID, we must shift gear and adopt these powerful hypothesis-free approaches through concerted actions and allocation of adequate resources. Provided these are in place, the major challenge will be, inevitably, the choice of the target phenotype(s) beyond a descriptive symptom-based classification. PURPOSE In view of these much awaited developments, salient results and difficulties inherent to IBS gene discovery are briefly summarized here.
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Affiliation(s)
- Mauro D'Amato
- Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.
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1044
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Kienhuis AS, Vitins AP, Pennings JL, Pronk TE, Speksnijder EN, Roodbergen M, van Delft JH, Luijten M, van der Ven LT. Cyclosporine A treated in vitro models induce cholestasis response through comparison of phenotype-directed gene expression analysis of in vivo Cyclosporine A-induced cholestasis. Toxicol Lett 2013; 221:225-36. [DOI: 10.1016/j.toxlet.2013.06.236] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 06/24/2013] [Accepted: 06/25/2013] [Indexed: 01/05/2023]
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1045
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Abstract
Bile acids are signaling molecules that activate nuclear receptors, such as farnesoid X receptor, pregnane X receptor, constitutive androstane receptor, and vitamin D receptor, and play a critical role in the regulation of lipid, glucose, energy, and drug metabolism. These xenobiotic/endobiotic-sensing nuclear receptors regulate phase I oxidation, phase II conjugation, and phase III transport in bile acid and drug metabolism in the digestive system. Integration of bile acid metabolism with drug metabolism controls absorption, transport, and metabolism of nutrients and drugs to maintain metabolic homeostasis and also protects against liver injury, inflammation, and related metabolic diseases, such as nonalcoholic fatty liver disease, diabetes, and obesity. Bile-acid-based drugs targeting nuclear receptors are in clinical trials for treating cholestatic liver diseases and fatty liver disease.
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Affiliation(s)
- Tiangang Li
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, Ohio 44272, USA
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1046
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Shang Q, Guo GL, Honda A, Saumoy M, Salen G, Xu G. FGF15/19 protein levels in the portal blood do not reflect changes in the ileal FGF15/19 or hepatic CYP7A1 mRNA levels. J Lipid Res 2013; 54:2606-14. [PMID: 23852734 DOI: 10.1194/jlr.m034827] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
It has been proposed that bile acid suppression of CYP7A1 gene expression is mediated through a gut-liver signaling pathway fibroblast growth factor (FGF)15/19-fibroblast growth factor receptor 4 which is initiated by activation of farnesoid X receptor in the ileum but not in the liver. This study evaluated whether FGF15/19 protein levels in the portal blood reflected changes in FGF15/19 mRNA in the ileum. Studies were conducted in Sprague Dawley rats and New Zealand white rabbits fed regular chow (controls), supplemented with cholesterol (Ch) or cholic acid (CA). After feeding CA, ileal FGF15 mRNA increased 8.5-fold in rats and FGF19 rose 16-fold in rabbits associated with 62 and 75% reduction of CYP7A1 mRNA, respectively. Neither FGF15 nor FGF19 protein levels changed in the portal blood to correspond with the marked increase of FGF15/19 mRNA levels in the ileum or inhibited CYP7A1 expression in the liver. Further, in Ch-fed rats, CYP7A1 mRNA increased 1.9-fold (P < 0.001) although FGF15 mRNA levels in the ileum and portal blood FGF15 protein levels were not decreased. In Ch-fed rabbits, although FGF19 mRNA levels in the ileum and liver did not increase significantly, CYP7A1 mRNA declined 49% (P < 0.05). We were unable to find corresponding changes of FGF15/19 protein levels in the portal blood in rats and rabbits where the mRNA levels of FGF15/19 in the ileum and CYP7A1 in the liver change significantly.
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Affiliation(s)
- Quan Shang
- Department of Medicine, New Jersey Medical School, Newark, NJ 07103
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1047
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Medium-chain fatty acids enhanced the excretion of fecal cholesterol and cholic acid in C57BL/6J mice fed a cholesterol-rich diet. Biosci Biotechnol Biochem 2013; 77:1390-6. [PMID: 23832358 DOI: 10.1271/bbb.120999] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The objective of the present study was to investigate the cholesterol-reducing effect of medium-chain fatty acids (MCFAs) completed by elevated excretion of fecal neutral steroids and/or bile acids. Blood and liver lipid profiles, fecal neutral steroids, bile acids, and mRNA and protein expression of the genes relevant to cholesterol homeostasis were measured and analyzed in C57BL/6J mice fed a cholesterol-rich diet with 2% caprylic acid or capric acid for 12 weeks. Blood total cholesterol and low-density lipoprotein cholesterol (LDL-c) levels were reduced significantly as compared to diet with palmitic acid or stearic acid. Caprylic acid promoted the excretion of fecal neutral steroids, especially cholesterol. The excretion of fecal bile acids, mainly in the form of cholic acid was enhanced and accompanied by elevated expression of mRNA and the protein of hepatic cholesterol 7α-hydroxylase (CYP7A1). These results indicate that MCFAs can reduce blood cholesterol by promoting the excretion of fecal cholesterol and cholic acid.
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1048
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Gerhard GS, Styer AM, Wood GC, Roesch SL, Petrick AT, Gabrielsen J, Strodel WE, Still CD, Argyropoulos G. A role for fibroblast growth factor 19 and bile acids in diabetes remission after Roux-en-Y gastric bypass. Diabetes Care 2013; 36:1859-64. [PMID: 23801799 PMCID: PMC3687273 DOI: 10.2337/dc12-2255] [Citation(s) in RCA: 175] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Roux-en-Y gastric bypass (RYGB) in humans can remit type 2 diabetes, but the operative mechanism is not completely understood. In mice, fibroblast growth factor (FGF) 15 (FGF19 in humans) regulates hepatic bile acid (BA) production and can also resolve diabetes. In this study, we tested the hypothesis that the FGF19-BA pathway plays a role in the remission of human diabetes after RYGB surgery. RESEARCH DESIGN AND METHODS Cohorts of diabetic and nondiabetic individuals of various body weights were used. In addition, RYGB patients without diabetes (No-Diabetes), RYGB patients with diabetes who experienced remission for at least 12 months after surgery (Diabetes-R), and RYGB patients with diabetes who did not go into remission after surgery (Diabetes-NoR) were studied. Circulating FGF19 and BA levels, hepatic glycogen content, and expression levels of genes regulating the FGF19-BA pathway were compared among these groups of patients using pre- and postoperative serum samples and intraoperative liver biopsies. RESULTS Preoperatively, patients with diabetes had lower FGF19 and higher BA levels than nondiabetic patients, irrespective of body weight. In diabetic patients undergoing RYGB, lower FGF19 levels were significantly correlated with increased hepatic expression of the cholesterol 7alpha-hydroxylase 1 (CYP7A1) gene, which modulates BA production. Following RYGB surgery, however, FGF19 and BA levels (particularly cholic and deoxycholic acids) exhibited larger increases in Diabetic-R patients compared with nondiabetic and Diabetic-NoR patients. CONCLUSIONS Taken together, the baseline and postoperative data implicate the FGF19-CYP7A1-BA pathway in the etiology and remission of type 2 diabetes following RYGB surgery.
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Affiliation(s)
- Glenn S Gerhard
- Weis Center for Research, Geisinger Clinic, Danville, Pennsylvania, USA
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1049
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Smilowitz JT, Zivkovic AM, Wan YJY, Watkins SM, Nording ML, Hammock BD, German JB. Nutritional lipidomics: molecular metabolism, analytics, and diagnostics. Mol Nutr Food Res 2013; 57:1319-35. [PMID: 23818328 DOI: 10.1002/mnfr.201200808] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 04/12/2013] [Accepted: 04/19/2013] [Indexed: 12/25/2022]
Abstract
The field of lipidomics is providing nutritional science a more comprehensive view of lipid intermediates. Lipidomics research takes advantage of the increase in accuracy and sensitivity of mass detection of MS with new bioinformatics toolsets to characterize the structures and abundances of complex lipids. Yet, translating lipidomics to practice via nutritional interventions is still in its infancy. No single instrumentation platform is able to solve the varying analytical challenges of the different molecular lipid species. Biochemical pathways of lipid metabolism remain incomplete and the tools to map lipid compositional data to pathways are still being assembled. Biology itself is dauntingly complex and simply separating biological structures remains a key challenge to lipidomics. Nonetheless, the strategy of combining tandem analytical methods to perform the sensitive, high-throughput, quantitative, and comprehensive analysis of lipid metabolites of very large numbers of molecules is poised to drive the field forward rapidly. Among the next steps for nutrition to understand the changes in structures, compositions, and function of lipid biomolecules in response to diet is to describe their distribution within discrete functional compartments lipoproteins. Additionally, lipidomics must tackle the task of assigning the functions of lipids as signaling molecules, nutrient sensors, and intermediates of metabolic pathways.
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1050
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Targher G, Scorletti E, Mantovani A, Byrne CD. Nonalcoholic fatty liver disease and reduced serum vitamin D(3) levels. Metab Syndr Relat Disord 2013; 11:217-28. [PMID: 23745619 DOI: 10.1089/met.2013.0044] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) and vitamin D3 deficiency are two highly prevalent pathologic conditions worldwide that share several cardiometabolic risk factors. In addition to its traditional calcium-related effects on the skeleton, vitamin D3 deficiency has now been recognized to exert nonskeletal adverse effects on several other organ systems. Accumulating epidemiological evidence suggests that low levels of serum 25-hydroxyvitamin D3 are associated with the presence and severity of NAFLD, independently of several potential confounders, including features of the metabolic syndrome. The molecular mechanisms of this association remain incompletely understood. A variety of biologically plausible mechanisms may mediate a hepato-protective role for the active metabolite of vitamin D3. 1α,25-dihydroxyvitamin D3 modulates the insulin signaling pathway/insulin resistance, suppresses fibroblast proliferation and collagen production, exerts anticoagulant and profibrinolytic effects, and modulates macrophage activity and inflammatory cytokine generation. Overall, the high prevalence of vitamin D3 deficiency and the plausible biological mechanisms linking this to NAFLD suggest that treatment of vitamin D3 deficiency to prevent and/or treat NAFLD is a promising field to explore. Large placebo-controlled randomized clinical trials are urgently needed to determine whether vitamin D3 supplementation could have any potential benefit in reducing the development and progression of NAFLD.
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Affiliation(s)
- Giovanni Targher
- Division of Endocrinology, Diabetes and Metabolism, University and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy.
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