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Liu Y, Liu T, Zhao X, Gao Y. New insights into the bile acid-based regulatory mechanisms and therapeutic perspectives in alcohol-related liver disease. Cell Mol Life Sci 2022; 79:486. [PMID: 35978227 PMCID: PMC11073206 DOI: 10.1007/s00018-022-04509-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/22/2022] [Accepted: 07/31/2022] [Indexed: 11/27/2022]
Abstract
Cholestasis is a key causative factor in alcohol-related liver disease (ALD) and variable degrees of cholestasis occur in all stages of ALD. However, the pathogenetic mechanisms and biomarkers associated with cholestasis are not well characterized. Cholestatic disease is marked by the disruption of bile acids (BA) transport and homeostasis. Consequently, in both human and experimental ALD, the disease shows a direct correlation with an imbalance in BA equilibrium, which in turn may also affect the severity of the disease. Modulation of BA metabolism or signaling pathways is increasingly considered as a potential therapeutic strategy for ALD in humans. In this paper, we highlight the key advances made in the past two decades in characterizing the molecular regulatory mechanisms of BA synthesis, enterohepatic circulation, and BA homeostasis. We summarize recent insights into the nature of the linkage between BA dysregulation and ALD, including the abnormal expression of genes involved in BA metabolism, abnormal changes in receptors that regulate BA metabolism, and disturbance in the gut flora engaged in BA metabolism caused by alcohol consumption. Additionally, we provide novel perspectives on the changes in BAs in various stages of ALD. Finally, we propose potential pharmacological therapies for ALD targeting BA metabolism and signaling.
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Affiliation(s)
- Yali Liu
- Department of Hepatology, The First Hospital of Jilin University, Jilin University, Changchun, 130021, Jilin, China
| | - Tao Liu
- Department of Hepatology, The First Hospital of Jilin University, Jilin University, Changchun, 130021, Jilin, China
| | - Xu Zhao
- Department of Hepatology, The First Hospital of Jilin University, Jilin University, Changchun, 130021, Jilin, China
| | - Yanhang Gao
- Department of Hepatology, The First Hospital of Jilin University, Jilin University, Changchun, 130021, Jilin, China.
- Center of Infectious Diseases and Pathogen Biology, The First Hospital of Jilin University, Changchun, China.
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2
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Chen W, Zhang Q, Ding M, Yao J, Guo Y, Yan W, Yu S, Shen Q, Huang M, Zheng Y, Lin Y, Wang Y, Liu Z, Lu L. Alcohol triggered bile acid disequilibrium by suppressing BSEP to sustain hepatocellular carcinoma progression. Chem Biol Interact 2022; 356:109847. [PMID: 35149083 DOI: 10.1016/j.cbi.2022.109847] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 01/20/2022] [Accepted: 02/07/2022] [Indexed: 12/12/2022]
Abstract
Bile acids (BAs), the most important components of bile, attribute predominately to maintain metabolic homeostasis. In hepatocellular carcinoma (HCC) patients, the BAs homeostasis was seriously disturbed, especially in those patients with alcohol-intake history. However, whether alcohol consumption could promote HCC progression via influencing BAs homeostasis and the precise mechanism underlying are still unclear. In our study, by collecting HCC specimens from both alcohol-drinkers (n = 15) and non-alcohol drinkers (n = 22), we found that compared to non-alcohol intake HCC patients, BAs homeostasis was disturbed in HCC patients who drank alcohol. Furthermore, ethanol treatment was also found to promote HCC progression by markedly activating oncogenes (RAS, MYC, MET, and HER2), while remarkably suppressing tumor suppressor genes (BRCA2 and APC). We evaluated 14 key functional genes that maintain the homeostasis of BAs and found that either in alcohol-intake HCC patients (n = 15), or in ethanol-treated mice, BSEP, rate-limiting transporter governing excreting BAs from liver into bile duct, was remarkably decreased when exposed to alcohol. Moreover, by screening for changes in the epigenetic landscape of liver cancer cells exposed to alcohol, we strikingly found that histone methyltransferases (RBBP-5, Suv39h1, ASH2L, and SET7/9) were increased, and KMT3B, KMT4, and KMT7 gene expression was also elevated, while histone demethyltransferases (JARID1a, JARID1b, JARID1c) were decreased. In summary, we found that alcohol could trigger BAs disequilibrium to initiate and promote HCC progression. Our study provided a novel and supplementary mechanism to determine the important role of alcohol-intake in HCC development regarding from the perspective of BAs homeostasis.
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Affiliation(s)
- Wenbo Chen
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Qisong Zhang
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China; Medical College of Guangxi University, Guangxi University, Nanning, Guangxi, 530004, PR China
| | - Ming Ding
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Jingjing Yao
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Yajuan Guo
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Wenxin Yan
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Shaofang Yu
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Qinghong Shen
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Min Huang
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Yaqiu Zheng
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Yuefang Lin
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Ying Wang
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China
| | - Zhongqiu Liu
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China; State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, SAR, China.
| | - Linlin Lu
- Joint Laboratory for Translational Cancer Research of Chinese Medicine of the Ministry of Education of the People's Republic of China, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China; State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macau, SAR, China.
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Gong X, Zhang Q, Ruan Y, Hu M, Liu Z, Gong L. Chronic Alcohol Consumption Increased Bile Acid Levels in Enterohepatic Circulation and Reduced Efficacy of Irinotecan. Alcohol Alcohol 2021; 55:264-277. [PMID: 32232424 DOI: 10.1093/alcalc/agaa005] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/10/2020] [Accepted: 01/21/2020] [Indexed: 12/13/2022] Open
Abstract
AIMS To investigate the effect of ethanol intake on the whole enterohepatic circulation (EHC) of bile acids (BAs) and, more importantly, on pharmacokinetics of irinotecan. METHODS The present study utilized a mouse model administered by gavage with 0 (control), 240 mg/100 g (30%, v/v) and 390 mg/100 g (50%, v/v) ethanol for 6 weeks, followed by BA profiles in the whole EHC (including liver, gallbladder, intestine and plasma) and colon using ultra-high performance liquid chromatography with tandem mass spectrometry analysis. Pharmacokinetic parameters of irinotecan were measured after administration of irinotecan (i.v. 5 mg/kg) on alcohol-treated mice. RESULTS The results showed that compared with the control group, concentrations of most free-BAs, total amount of the three main forms of BAs (free-BA, taurine-BA and glycine-BA) and total BAs (TBAs) in 50% ethanol intake group were significantly increased, which are mostly attributed to the augmentation of free-BAs and taurine-BAs. Additionally, the TBAs in liver and gallbladder and the BA pool were markedly increased in the 30% ethanol intake group. Importantly, ethanol intake upregulated the expression of BA-related enzymes (Cyp7a1, Cyp27a1, Cyp8b1 and Baat) and transporters (Bsep, Mrp2, P-gp and Asbt) and downregulated the expression of transporter Ntcp and nuclear receptor Fxr in the liver and ileum, respectively. Additionally, 50% ethanol intake caused fairly distinct liver injury. Furthermore, the AUC0-24 h of irinotecan and SN38 were significantly reduced but their clearance was significantly increased in the disrupted EHC of BA by 50% ethanol intake. CONCLUSIONS The present study demonstrated that ethanol intake altered the expression of BA-related synthetases and transporters. The BA levels, especially the toxic BAs (chenodeoxycholic acid, deoxycholic acid and lithocholic acid), in the whole EHC were significantly increased by ethanol intake, which may provide a potential explanation to illuminate the pathogenesis of alcoholic liver injury. Most importantly, chronic ethanol consumption had a significant impact on the pharmacokinetics (AUC0-24 h and clearance) of irinotecan and SN38; hence colon cancer patients with chronic alcohol consumption treated with irinotecan deserve our close attention.
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Affiliation(s)
- Xia Gong
- 232 Waihuan Donglu, Guangzhou Daxuecheng, Panyu District, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, PR China
| | - Qisong Zhang
- 232 Waihuan Donglu, Guangzhou Daxuecheng, Panyu District, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, PR China
| | - Yanjiao Ruan
- 232 Waihuan Donglu, Guangzhou Daxuecheng, Panyu District, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, PR China
| | - Ming Hu
- 232 Waihuan Donglu, Guangzhou Daxuecheng, Panyu District, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, PR China.,Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Huston, 1441 Moursund St., Houston, TX 77030, USA
| | - Zhongqiu Liu
- 232 Waihuan Donglu, Guangzhou Daxuecheng, Panyu District, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, PR China
| | - Lingzhi Gong
- 232 Waihuan Donglu, Guangzhou Daxuecheng, Panyu District, International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong 510006, PR China
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Wang X, Zheng L, Wu J, Tang B, Zhang M, Zhu D, Lin X. Constitutive androstane receptor activation promotes bilirubin clearance in a murine model of alcoholic liver disease. Mol Med Rep 2017; 15:3459-3466. [PMID: 28393244 PMCID: PMC5436297 DOI: 10.3892/mmr.2017.6435] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 11/29/2016] [Indexed: 12/20/2022] Open
Abstract
Increased plasma levels of bilirubin have been reported in rat models and patients with alcoholic liver disease (ALD). The constitutive androstane receptor (CAR) is a known xenobiotic receptor, which induces the detoxification and transport of bilirubin. In the present study, the bilirubin transport regulatory mechanisms, and the role of CAR activation in hepatic and extrahepatic bilirubin clearance were investigated in a murine model of ALD. The mice were fed a Lieber-DeCarli ethanol diet or an isocaloric control diet for 4 weeks, followed by the administration of CAR agonists, 1,4-bis-[2-(3,5-dichlorpyridyloxy)]benzene (TCPOBOP) and phenobarbital (PB), and their vehicles to examine the effect of the pharmacological activation of CAR on serum levels of bilirubin and on the bilirubin clearance pathway in ALD by serological survey, western blotting and reverse transcription-quantitative polymerase chain reaction. The results showed that chronic ethanol ingestion impaired the nuclear translocation of CAR, which was accompanied by elevated serum levels of bilirubin, suppression of the expression of hepatic and renal organic anion transporting polypeptide (OATP) 1A1 and hepatic multidrug resistance-associated protein 2 (MRP2), and induction of the expression of UDP-glucuronosyltransferase (UGT) 1A1. The activation of CAR by TCPOBOP and PB resulted in downregulation of the serum levels of bilirubin followed by selective upregulation of the expression levels of OATP1A1, OATP1A4, UGT1A1 and MRP2 in ALD. These results revealed the bilirubin transport regulatory mechanisms and highlighted the importance of CAR in modulating the bilirubin clearance pathway in the ALD mouse model.
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Affiliation(s)
- Xiuyan Wang
- Department of Gastroenterology, Wenzhou People's Hospital, Wenzhou, Zhejiang 325000, P.R. China
| | - Liyu Zheng
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Jinming Wu
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Binbin Tang
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Mengqin Zhang
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Debin Zhu
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Xianfan Lin
- Department of Gastroenterology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
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Subramanian VS, Srinivasan P, Said HM. Uptake of ascorbic acid by pancreatic acinar cells is negatively impacted by chronic alcohol exposure. Am J Physiol Cell Physiol 2016; 311:C129-35. [PMID: 27122159 DOI: 10.1152/ajpcell.00042.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 04/20/2016] [Indexed: 12/21/2022]
Abstract
Vitamin C (ascorbic acid, AA) is indispensable for normal metabolism of all mammalian cells including pancreatic acinar cells (PACs). PACs obtain AA from their surroundings via transport across the cell membrane. Chronic alcohol exposure negatively affects body AA homeostasis; it also inhibits uptake of other micronutrients into PACs, but its effect on AA uptake is not clear. We examined this issue using both in vitro (266-6 cells) and in vivo (mice) models of chronic alcohol exposure. First, we determined the relative expression of the AA transporters 1 and 2 [i.e., sodium-dependent vitamin C transporter-1 (SVCT-1) and SVCT-2] in mouse and human PACs and found SVCT-2 to be the predominant transporter. Chronic exposure of 266-6 cells to alcohol significantly inhibited AA uptake and caused a marked reduction in SVCT-2 expression at the protein, mRNA, and heterogeneous nuclear RNA (hnRNA) levels. Similarly, chronic alcohol feeding of mice significantly inhibited AA uptake and caused a marked reduction in level of expression of the SVCT-2 protein, mRNA, and hnRNA. These findings suggest possible involvement of transcriptional mechanism(s) in mediating chronic alcohol effect on AA uptake by PACs. We also observed significant epigenetic changes (histone modifications) in the Slc23a2 gene (reduction in H3K4me3 level and an increase in H3K27me3 level) in the alcohol-exposed 266-6 cells. These findings show that chronic alcohol exposure inhibits PAC AA uptake and that the effect is mediated, in part, at the level of transcription of the Slc23a2 gene and may involve epigenetic mechanism(s).
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Affiliation(s)
- Veedamali S Subramanian
- Department of Medicine, University of California, Irvine, California; Department of Physiology, University of California, Irvine, California; Department of Biophysics, University of California, Irvine, California; Department of Veterans Affairs Medical Center, Long Beach, California
| | - Padmanabhan Srinivasan
- Department of Medicine, University of California, Irvine, California; Department of Physiology, University of California, Irvine, California; Department of Biophysics, University of California, Irvine, California; Department of Veterans Affairs Medical Center, Long Beach, California
| | - Hamid M Said
- Department of Medicine, University of California, Irvine, California; Department of Physiology, University of California, Irvine, California; Department of Biophysics, University of California, Irvine, California; Department of Veterans Affairs Medical Center, Long Beach, California
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Yinzhihuang attenuates ANIT-induced intrahepatic cholestasis in rats through upregulation of Mrp2 and Bsep expressions. Pediatr Res 2016; 79:589-95. [PMID: 26646631 DOI: 10.1038/pr.2015.252] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 09/16/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND The treatment of intrahepatic cholestasis has been limited, and development of an effective drug is needed. Clinical studies have shown that Yinzhihuang (YZH), a traditional Chinese decoction, enhances bilirubin clearance. The goal of this study was to determine the protective effect of YZH on experimental intrahepatic cholestasis in young rats and to explore its underlying molecular mechanisms. METHODS Intrahepatic cholestasis in rats was induced by α-naphthylisothiocyanate (ANIT) on days 1 and 8. The rats received YZH, ursodeoxycholic acid (UDCA), or vehicle for 9 d and were killed on either day 3 or day 10. Serum biomarkers, liver histology, and the distribution of protein and mRNA expression of Mrp2 and Bsep were analyzed. RESULTS YZH treatment resulted in decreased levels of serum biomarkers except γ-glutamyl transpeptidase, attenuated liver histological injuries, increased protein expressions of Mrp2 and Bsep, and upregulated expressions of Mrp2 and Bsep mRNAs. The effects of YZH on serum biomarkers (aminotransferase, alanine aminotransferase, and direct bilirubin), liver histology, and Mrp2 mRNA expressions were significantly greater and earlier than those of UDCA. CONCLUSION Our results suggest that YZH has protective effect against ANIT-induced intrahepatic cholestasis in rats, through upregulation of Mrp2 and Bsep expressions.
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Theile D, Schmidt TT, Haefeli WE, Weiss J. In-vitro evaluation of chronic alcohol effects on expression of drug-metabolizing and drug-transporting proteins. J Pharm Pharmacol 2013; 65:1518-25. [DOI: 10.1111/jphp.12124] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 07/04/2013] [Indexed: 01/16/2023]
Abstract
Abstract
Objectives
In alcoholics without alcoholic liver disease, boosted drug elimination has been reported. However, mechanistic explanations for this phenomenon remain uncertain. In particular, data on the potential role of drug transporters are sparse.
Methods
Using a well-established in-vitro model for induction of human drug-metabolizing and drug-transporting proteins, we evaluated the potency of ethanol and the major fermentation side-product isopentanol to alter expression and function of these proteins by quantitative real-time polymerase chain reaction, Western blotting and flow cytometry. P-glycoprotein (Pgp)-inhibiting properties of ethanol and isopentanol were investigated via calcein extrusion assay.
Key findings
Ethanol and isopentanol significantly changed expression levels of drug-metabolizing and drug-transporting proteins that normalized within 2 weeks upon withdrawal. Cytochrome P-450 2C19 and Pgp were most strongly induced. Ethanol-induced Pgp at the messenger RNA (mRNA) (twofold to eightfold) and protein level (twofold), but not at the functional level. Both compounds did not inhibit Pgp.
Conclusions
Ethanol is demonstrated to increase mRNA and protein expression of human drug transporters such as Pgp in vitro. Withdrawal of ethanol exposure causes return to non-induced conditions within weeks. Functional consequences of increased Pgp expression in alcoholics need to be evaluated by clinical trials applying selective Pgp substrates such as digoxin.
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Affiliation(s)
- Dirk Theile
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
| | - Tobias T Schmidt
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
| | - Walter E Haefeli
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
| | - Johanna Weiss
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
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Subramanian VS, Subramanya SB, Ghosal A, Said HM. Chronic alcohol feeding inhibits physiological and molecular parameters of intestinal and renal riboflavin transport. Am J Physiol Cell Physiol 2013; 305:C539-46. [PMID: 23804199 DOI: 10.1152/ajpcell.00089.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Vitamin B2 (riboflavin, RF) is essential for normal human health. Mammals obtain RF from exogenous sources via intestinal absorption and prevent its urinary loss by reabsorption in the kidneys. Both of these absorptive events are carrier-mediated and involve specific RF transporters (RFVTs). Chronic alcohol consumption in humans is associated with a high prevalence of RF deficiency and suboptimal levels, but little is known about the effect of chronic alcohol exposure on physiological and molecular parameters of the intestinal and renal RF transport events. We addressed these issues using rats chronically fed an alcohol liquid diet and pair-fed controls as a model. The results showed that chronic alcohol feeding significantly inhibits carrier-mediated RF transport across the intestinal brush-border and basolateral membrane domains of the polarized enterocytes. This inhibition was associated with a parallel reduction in the expression of the rat RFVT-1 and -3 at the protein, mRNA, and heterogeneous nuclear RNA (hnRNA) levels. Chronic alcohol feeding also caused a significant inhibition in RF uptake in the colon. Similarly, a significant inhibition in carrier-mediated RF transport across the renal brush-border and basolateral membrane domains was observed, which again was associated with a significant reduction in the level of expression of RFVT-1 and -3 at the protein, mRNA, and hnRNA levels. These findings demonstrate that chronic alcohol exposure impairs both intestinal absorption and renal reabsorption processes of RF and that these effects are, at least in part, mediated via transcriptional mechanism(s) involving the slc52a1 and slc52a3 genes.
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Affiliation(s)
- Veedamali S Subramanian
- Department of Medicine and Physiology/Biophysics, University of California, Irvine, California, USA
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Quantifying spatial correlations of fluorescent markers using enhanced background reduction with protein proximity index and correlation coefficient estimations. Nat Protoc 2011; 6:1554-67. [PMID: 21959238 DOI: 10.1038/nprot.2011.384] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Interactions of proteins are examined by detecting their overlap using fluorescent markers. The observed overlap is then quantified to serve as a measure of spatial correlation. A major drawback of this approach is that it can produce false values because of the properties of the image background. To remedy this, we provide a protocol to reduce the contribution of image background and then apply a protein proximity index (PPI) and correlation coefficient to estimate colocalization. Background heterogeneity is reduced by the median filtering procedure, comprising two steps, to reduce random noise and background, respectively. Alternatively, background can be reduced by advanced thresholding. PPI provides separate values for each channel to characterize the contribution of each protein, whereas correlation coefficient determines the overall colocalization. The protocol is demonstrated using computer-simulated and real biological images. It minimizes human bias and can be universally applied to various cell types in which there is a need to understand protein-protein interactions. Background reductions require 3-5 min per image. Quantifications take <1 min. The entire procedure takes approximately 15-30 min.
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Stieger B. The role of the sodium-taurocholate cotransporting polypeptide (NTCP) and of the bile salt export pump (BSEP) in physiology and pathophysiology of bile formation. Handb Exp Pharmacol 2011:205-59. [PMID: 21103971 DOI: 10.1007/978-3-642-14541-4_5] [Citation(s) in RCA: 200] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bile formation is an important function of the liver. Bile salts are a major constituent of bile and are secreted by hepatocytes into bile and delivered into the small intestine, where they assist in fat digestion. In the small intestine, bile salts are almost quantitatively reclaimed and transported back via the portal circulation to the liver. In the liver, hepatocytes take up bile salts and secrete them again into bile for ongoing enterohepatic circulation. Uptake of bile salts into hepatocytes occurs largely in a sodium-dependent manner by the sodium taurocholate cotransporting polypeptide NTCP. The transport properties of NTCP have been extensively characterized. It is an electrogenic member of the solute carrier family of transporters (SLC10A1) and transports predominantly bile salts and sulfated compounds, but is also able to mediate transport of additional substrates, such as thyroid hormones, drugs and toxins. It is highly regulated under physiologic and pathophysiologic conditions. Regulation of NTCP copes with changes of bile salt load to hepatocytes and prevents entry of cytotoxic bile salts during liver disease. Canalicular export of bile salts is mediated by the ATP-binding cassette transporter bile salt export pump BSEP (ABCB11). BSEP constitutes the rate limiting step of hepatocellular bile salt transport and drives enterohepatic circulation of bile salts. It is extensively regulated to keep intracellular bile salt levels low under normal and pathophysiologic situations. Mutations in the BSEP gene lead to severe progressive familial intrahepatic cholestasis. The substrates of BSEP are practically restricted to bile salts and their metabolites. It is, however, subject to inhibition by endogenous metabolites or by drugs. A sustained inhibition will lead to acquired cholestasis, which can end in liver injury.
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Affiliation(s)
- Bruno Stieger
- Division of Clinical Pharmacology and Toxicology, University Hospital, 8091, Zurich, Switzerland.
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11
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Gu X, Manautou JE. Regulation of hepatic ABCC transporters by xenobiotics and in disease states. Drug Metab Rev 2010; 42:482-538. [PMID: 20233023 DOI: 10.3109/03602531003654915] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The subfamily of ABCC transporters consists of 13 members in mammals, including the multidrug resistance-associated proteins (MRPs), sulfonylurea receptors (SURs), and the cystic fibrosis transmembrane conductance regulator (CFTR). These proteins play roles in chemical detoxification, disposition, and normal cell physiology. ABCC transporters are expressed differentially in the liver and are regulated at the transcription and translation level. Their expression and function are also controlled by post-translational modification and membrane-trafficking events. These processes are tightly regulated. Information about alterations in the expression of hepatobiliary ABCC transporters could provide important insights into the pathogenesis of diseases and disposition of xenobiotics. In this review, we describe the regulation of hepatic ABCC transporters in humans and rodents by a variety of xenobiotics, under disease states and in genetically modified animal models deficient in transcription factors, transporters, and cell-signaling molecules.
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Affiliation(s)
- Xinsheng Gu
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, 06269, USA
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Recent advances in quantitative colocalization analysis: Focus on neuroscience. ACTA ACUST UNITED AC 2009; 44:125-72. [DOI: 10.1016/j.proghi.2009.03.001] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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13
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State-of-the-art technologies, current opinions and developments, and novel findings: news from the field of histochemistry and cell biology. Histochem Cell Biol 2008; 130:1205-51. [PMID: 18985372 DOI: 10.1007/s00418-008-0535-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2008] [Indexed: 10/25/2022]
Abstract
Investigations of cell and tissue structure and function using innovative methods and approaches have again yielded numerous exciting findings in recent months and have added important data to current knowledge, inspiring new ideas and hypotheses in various fields of modern life sciences. Topics and contents of comprehensive expert reviews covering different aspects in methodological advances, cell biology, tissue function and morphology, and novel findings reported in original papers are summarized in the present review.
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Abstract
The progress in discerning the structure and function of cells and tissues in health and disease has been achieved to a large extent by the continued development of new reagents for histochemistry, the improvement of existing techniques and new imaging techniques. This review will highlight some advancements made in these fields.
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