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Guan L, Zhang L, Gong D, Li P, Zhu S, Tang J, Du M, Zhang M, Zou Y. Genipin improves obesity through promoting bile secretion and changing bile acids composition in diet-induced obese rats. J Pharm Pharmacol 2024; 76:897-907. [PMID: 38727186 DOI: 10.1093/jpp/rgae055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 04/23/2024] [Indexed: 07/06/2024]
Abstract
OBJECTIVES Bile acids (BAs), as signaling molecules to regulate metabolism, have received considerable attention. Genipin is an iridoid compound extracted from Fructus Gradeniae, which has been shown to relieve adiposity and metabolic syndrome. Here, we investigated the mechanism of genipin counteracting obesity and its relationship with BAs signals in diet-induced obese (DIO) rats. METHODS The DIO rats were received intraperitoneal injections of genipin for 10 days. The body weight, visceral fat, lipid metabolism in the liver, thermogenic genes expressions in brown fat, BAs metabolism and signals, and key enzymes for BAs synthesis were determined. KEY FINDINGS Genipin inhibited fat synthesis and promoted lipolysis in the liver, and upregulated thermogenic gene expressions in brown adipose tissue of DIO rats. Genipin increased bile flow rate and upregulated the expressions of aquaporin 8 and the transporters of BAs in liver. Furthermore, genipin changed BAs composition by promoting alternative pathways and inhibiting classical pathways for BAs synthesis and upregulated the expressions of bile acid receptors synchronously. CONCLUSIONS These results suggest that genipin ameliorate obesity through BAs-mediated signaling pathways.
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Affiliation(s)
- Lili Guan
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Lei Zhang
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Dezheng Gong
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Pengcheng Li
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Shengnan Zhu
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Jiulan Tang
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Man Du
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Maokun Zhang
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
| | - Yuan Zou
- Department of Physiology, Dalian Medical University, Dalian, Liaoning Province 116044, China
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Calamita G, Delporte C. Insights into the Function of Aquaporins in Gastrointestinal Fluid Absorption and Secretion in Health and Disease. Cells 2023; 12:2170. [PMID: 37681902 PMCID: PMC10486417 DOI: 10.3390/cells12172170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Revised: 08/16/2023] [Accepted: 08/17/2023] [Indexed: 09/09/2023] Open
Abstract
Aquaporins (AQPs), transmembrane proteins permeable to water, are involved in gastrointestinal secretion. The secretory products of the glands are delivered either to some organ cavities for exocrine glands or to the bloodstream for endocrine glands. The main secretory glands being part of the gastrointestinal system are salivary glands, gastric glands, duodenal Brunner's gland, liver, bile ducts, gallbladder, intestinal goblet cells, exocrine and endocrine pancreas. Due to their expression in gastrointestinal exocrine and endocrine glands, AQPs fulfill important roles in the secretion of various fluids involved in food handling. This review summarizes the contribution of AQPs in physiological and pathophysiological stages related to gastrointestinal secretion.
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Affiliation(s)
- Giuseppe Calamita
- Department of Biosciences, Biotechnologies and Environment, University of Bari Aldo Moro, 70125 Bari, Italy;
| | - Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, 1070 Brussels, Belgium
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Xiang M, Qian X, Han L, Wang H, Wang J, Liu W, Gu Y, Yao S, Yang J, Zhang Y, Peng Y, Zhang Z. Aquaporin-8 ameliorates hepatic steatosis through farnesoid X receptor in obese mice. iScience 2023; 26:106561. [PMID: 37123234 PMCID: PMC10130924 DOI: 10.1016/j.isci.2023.106561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 08/17/2022] [Accepted: 03/28/2023] [Indexed: 04/03/2023] Open
Abstract
Aquaporin-8(AQP8), is a transmembrane channel protein that abounds in liver, which mainly promotes water transport, modulating bile acid formation. However, its role in hepatic lipid metabolism remains unclear. In this study, we found the expression of AQP8 was reduced in liver specimens of patients with NAFLD, high-fat diet (HFD)-induced mice and genetically obese db/db mice. Knockdown of AQP8 in hepatocytes exacerbated the intracellular lipid accumulation induced by free fatty acid (FFA) mixtures. In contrast, hepatic AQP8 overexpression activated farnesoid X receptor (FXR), inhibiting gene expression associated with lipogenesis, which further reduced intrahepatic triglyceride overload in obese mice. FXR knockout abrogated the ameliorating effect of AQP8 overexpression on NAFLD in mice. These findings indicate that AQP8 overexpression protects against fatty liver through activating the FXR pathway.
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Affiliation(s)
- Minqi Xiang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xu Qian
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Luyu Han
- Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hui Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jiqiu Wang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Weiren Liu
- Department of Liver Surgery and Transplantation, Liver Cancer Institute, Zhongshan Hospital, Fudan University, Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education, Shanghai, China
| | - Yanyun Gu
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shuangshuang Yao
- Department of Endocrinology and Metabolism, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Yang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yifei Zhang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ying Peng
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhiguo Zhang
- Department of Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Shanghai National Clinical Research Center for Metabolic Diseases, Key Laboratory for Endocrine and Metabolic Diseases of the National Health Commission of the PR China, Shanghai Key Laboratory for Endocrine Tumor, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Li X, Yang B. Non-Transport Functions of Aquaporins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1398:65-80. [PMID: 36717487 DOI: 10.1007/978-981-19-7415-1_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Although it has been more than 20 years since the first aquaporin was discovered, the specific functions of many aquaporins are still under investigation, because various mice lacking aquaporins have no significant phenotypes. And in many studies, the function of aquaporin is not directly related to its transport function. Therefore, this chapter will focus on some unexpected functions of aquaporins, such the decreased tumor angiogenesis in AQP1 knockout mice, and AQP1 promotes cell migration, possibly by accelerating the water transport in lamellipodia of migrating cells. AQP transports glycerol, and water regulates glycerol content in epidermis and fat, thereby regulating skin hydration/biosynthesis and fat metabolism. AQPs may also be involved in neural signal transduction, cell volume regulation, and organelle physiology. AQP1, AQP3, and AQP5 are also involved in cell proliferation. In addition, AQPs have also been reported to play roles in inflammation in various tissues and organs. The functions of these AQPs may not depend on the permeability of small molecules such as water and glycerol, suggesting AQPs may play more roles in different biological processes in the body.
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Affiliation(s)
- Xiaowei Li
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Pharmacology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Baoxue Yang
- School of Basic Medical Sciences, Peking University, Beijing, China.
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Lin J, Li M, Mak W, Shi Y, Zhu X, Tang Z, He Q, Xiang X. Applications of In Silico Models to Predict Drug-Induced Liver Injury. TOXICS 2022; 10:788. [PMID: 36548621 PMCID: PMC9785299 DOI: 10.3390/toxics10120788] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 06/17/2023]
Abstract
Drug-induced liver injury (DILI) is a major cause of the withdrawal of pre-marketed drugs, typically attributed to oxidative stress, mitochondrial damage, disrupted bile acid homeostasis, and innate immune-related inflammation. DILI can be divided into intrinsic and idiosyncratic DILI with cholestatic liver injury as an important manifestation. The diagnosis of DILI remains a challenge today and relies on clinical judgment and knowledge of the insulting agent. Early prediction of hepatotoxicity is an important but still unfulfilled component of drug development. In response, in silico modeling has shown good potential to fill the missing puzzle. Computer algorithms, with machine learning and artificial intelligence as a representative, can be established to initiate a reaction on the given condition to predict DILI. DILIsym is a mechanistic approach that integrates physiologically based pharmacokinetic modeling with the mechanisms of hepatoxicity and has gained increasing popularity for DILI prediction. This article reviews existing in silico approaches utilized to predict DILI risks in clinical medication and provides an overview of the underlying principles and related practical applications.
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Affiliation(s)
| | | | | | | | | | | | - Qingfeng He
- Correspondence: (Q.H.); (X.X.); Tel.: +86-21-51980024 (X.X.)
| | - Xiaoqiang Xiang
- Correspondence: (Q.H.); (X.X.); Tel.: +86-21-51980024 (X.X.)
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Liao M, Yu W, Xie Q, Zhang L, Pan Q, Zhao N, Li L, Cheng Y, Zhang X, Sun D, Chai J. Hepatic Aquaporin 10 Expression Is Downregulated by Activated NFκB Signaling in Human Obstructive Cholestasis. GASTRO HEP ADVANCES 2022; 2:412-423. [PMID: 39132646 PMCID: PMC11307722 DOI: 10.1016/j.gastha.2022.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 11/01/2022] [Indexed: 08/13/2024]
Abstract
Background and Aims Recent studies reported that the hepatic expression of AQP8 and AQP9 was downregulated in bile duct-ligated (BDL) rats and that overexpression of human AQP1 in the rat liver attenuated cholestasis. However, the hepatic expression of AQP10 and its regulatory mechanism in human cholestasis remain unclear. Methods Serum and liver samples were collected from 34 patients with obstructive cholestasis and from 12 control patients. Eight-week-old male C57BL/6J mice were intravenously injected with an adeno-associated virus 8 (AAV8) encoding human AQP10 driven by a hepatocyte-specific Alb promotor (AAV8-Alb promotor-hAQP10) for functional studies. Constructs of the AQP10 promoter and PLC/PRF/5-ASBT cell lines were used for regulatory mechanism studies. Results AQP10 was significantly downregulated in patients with obstructive cholestasis and negatively associated with the serum levels of total bile acid (TBA). The hepatocyte-specific overexpression of hAQP10 significantly attenuated the cholestatic liver injury and intrahepatic bile acids (BA) accumulation in BDL mice. Conjugated BAs, such as TCA and inflammatory factor TNFα, significantly repressed AQP10 expression. Furthermore, NFκB p65/p50 directly bound to the AQP10 promotor and decreased its activity in PLC/RPF/5-ASBT cells and in the livers of patients with obstructive cholestasis. However, these changes were diminished by BAY 11-7082 (a specific inhibitor of NFκB signaling). Conclusion We are the first to report that AQP10 was significantly decreased in patients with obstructive cholestasis. AQP10 overexpression significantly attenuated cholestatic liver injury in BDL mice. Therefore, overexpression of hAQP10 in the liver may be a valuable strategy for cholestasis intervention.
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Affiliation(s)
- Min Liao
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Wenjing Yu
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Marine College, Shandong University, Weihai, China
| | - Qiaoling Xie
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Liangjun Zhang
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Qiong Pan
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Nan Zhao
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Ling Li
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Ying Cheng
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Xiaoxun Zhang
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
| | - Dequn Sun
- School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, China
| | - Jin Chai
- Department of Gastroenterology, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Institute of Digestive Diseases of PLA, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
- Center for Cholestatic Liver Diseases and Center for Metabolic-Associated Fatty Liver Diseases, The First Affiliated Hospital (Southwest Hospital), Third Military Medical University (Army Medical University), Chongqing, China
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Hepatobiliary Thyroid Hormone Deficiency Impacts Bile Acid Hydrophilicity and Aquaporins in Cholestatic C57BL/6J Mice. Int J Mol Sci 2022; 23:ijms232012355. [PMID: 36293210 PMCID: PMC9603918 DOI: 10.3390/ijms232012355] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 10/12/2022] [Indexed: 11/07/2022] Open
Abstract
Women are more prone to develop either hypothyroidism or cholesterol gallstones than men. However, a male predominance in cholesterol gallstones under hypothyroidism was reported. Recently, a novel pathogenic link between thyroid hormone (TH) deficiency and cholesterol gallstones has been described in male mice. Here, we investigate if TH deficiency impacts cholesterol gallstone formation in females by the same mechanism. Three-month-old C57BL/6J mice were randomly divided into a control, a TH deficient, a lithogenic, and a lithogenic + TH deficient group and diet-treated for two, four, and six weeks. Gallstone prevalence, liver function tests, bile composition, hepatic gene expression, and gallbladder aquaporin expression and localization were investigated. Cholesterol gallstones were observed in lithogenic + TH deficient but not lithogenic only female mice. Diminished hydrophilicity of primary bile acids due to decreased gene expression of hepatic detoxification phase II enzymes was observed. A sex-specific expression and localization of hepatobiliary aquaporins involved in transcellular water and glycerol permeability was observed under TH deficient and lithogenic conditions. TH deficiency promotes cholesterol gallstone formation in female C57BL/6J mice by the same mechanism as observed in males. However, cholesterol gallstone prevalence was lower in female than male C57BL/6J mice. Interestingly, the sex-specific expression and localization of hepatobiliary aquaporins could protect female C57BL/6J mice to cholestasis and could reduce biliary water transport in male C57BL/6J mice possibly contributing to the sex-dependent cholesterol gallstone prevalence under TH deficiency.
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Zu Y, Yang J, Zhang C, Liu D. The Pathological Mechanisms of Estrogen-Induced Cholestasis: Current Perspectives. Front Pharmacol 2021; 12:761255. [PMID: 34819862 PMCID: PMC8606790 DOI: 10.3389/fphar.2021.761255] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/26/2021] [Indexed: 12/31/2022] Open
Abstract
Estrogens are steroid hormones with a wide range of biological activities. The excess of estrogens can lead to decreased bile flow, toxic bile acid (BA) accumulation, subsequently causing intrahepatic cholestasis. Estrogen-induced cholestasis (EIC) may have increased incidence during pregnancy, and within women taking oral contraception and postmenopausal hormone replacement therapy, and result in liver injury, preterm birth, meconium-stained amniotic fluid, and intrauterine fetal death in pregnant women. The main pathogenic mechanisms of EIC may include deregulation of BA synthetic or metabolic enzymes, and BA transporters. In addition, impaired cell membrane fluidity, inflammatory responses and change of hepatocyte tight junctions are also involved in the pathogenesis of EIC. In this article, we review the role of estrogens in intrahepatic cholestasis, and outlined the mechanisms of EIC, providing a greater understanding of this disease.
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Affiliation(s)
- Yue Zu
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinyu Yang
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chengliang Zhang
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dong Liu
- Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Aquaporins implicated in the cell proliferation and the signaling pathways of cell stemness. Biochimie 2021; 188:52-60. [PMID: 33894294 DOI: 10.1016/j.biochi.2021.04.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 04/11/2021] [Accepted: 04/16/2021] [Indexed: 12/20/2022]
Abstract
Aquaporins (AQPs) are water channel proteins facilitating passive transport of water and other small molecules across biomembranes. Regulation of osmotic homeostasis via AQPs is accompanied by dynamic participation of various cellular signaling pathways. Recently emerging evidence reveals that functional roles of AQPs are further extended from the osmotic regulation via water permeation into the cell proliferation and differentiation. In particular, anomalous expression of AQPs has been demonstrated in various types of cancer cells and cancer stem-like cells and it has been proposed as markers for proliferation and progression of cancer cells. Thus, a more comprehensive view on AQPs could bring a great interest in the cell stemness accompanied by the expression of AQPs. AQPs are broadly expressed across tissues and cells in a cell type- and lineage-specific manner during development via spatiotemporal transcriptional regulation. Moreover, AQPs are expressed in various adult stem cells and cells associated with a stem cell niche as well as cancer stem-like cells. However, the expression and regulatory mechanisms of AQP expression in stem cells have not been well understood. This review highlighted the AQPs expression in stem cell niches/stem cells and the involvement of AQPs in the cell proliferation and signaling pathways associated with cell stemness.
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10
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Javitt NB. Hepatic bile formation: bile acid transport and water flow into the canalicular conduit. Am J Physiol Gastrointest Liver Physiol 2020; 319:G609-G618. [PMID: 32935994 DOI: 10.1152/ajpgi.00078.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Advances in molecular biology identifying the many carrier-mediated organic anion transporters and advances in microscopy that have provided a more detailed anatomy of the canalicular conduit make updating the concept of osmotically determined canalicular flow possible. For the most part water flow is not transmembrane but via specific pore proteins in both the hepatocyte and the tight junction. These pores independently regulate the rate at which water flows in response to an osmotic gradient and therefore are determinants of canalicular bile acid concentration. Review of the literature indicates that the initial effect on hepatic bile flow of cholestatic agents such as Thorazine and estradiol 17β-glucuronide are on water flow and not bile salt export pump-mediated bile acid transport and thus provides new approaches to the pathogenesis of drug-induced liver injury. Attaining a micellar concentration of bile acids in the canaliculus is essential to the formation of cholesterol-lecithin vesicles, which mostly occur in the periportal region of the canalicular conduit. The other regions, midcentral and pericentral, may transport lesser amounts of bile acid but augment water flow. Broadening the concept of how hepatic bile flow is initiated, provides new insights into the pathogenesis of canalicular cholestasis.
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Affiliation(s)
- Norman B Javitt
- Division of Gastroenterology and Hepatology, New York University Grossman School of Medicine, New York, New York
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Abstract
Emerging evidence has shown that bile acids play important roles in renal physiology and diseases by activating two major receptors, the nuclear farnesoid X receptor (FXR) and the membrane G protein-coupled bile acid receptor-1 (Gpbar1; also known as TGR5). Both FXR and TGR5 have been identified in human and rodent kidneys, where they are deeply involved in renal water handling. In mice, FXR- or TGR5-related gene deficiency has been associated with reduced aquaporin-2 expression accompanied with impaired urinary concentration ability. In this mini-review, we briefly discuss the current understanding of FXR/TGR5 signaling in the kidneys, with a special focus on the regulation of aquaporin-2 expression by bile acids in the collecting ducts and its potential significance in disease conditions.
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Affiliation(s)
- Suchun Li
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Chunling Li
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Weidong Wang
- Institute of Hypertension, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
- Department of Pathophysiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
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Sisto M, Ribatti D, Lisi S. Aquaporin water channels: New perspectives on the potential role in inflammation. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 116:311-345. [PMID: 31036295 DOI: 10.1016/bs.apcsb.2018.11.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Aquaporins (AQPs) are a family of membrane water channel proteins that osmotically modulate water fluid homeostasis in several tissues; some of them also transport small solutes such as glycerol. At the cellular level, the AQPs regulate not only cell migration and transepithelial fluid transport across membranes, but also common events that are crucial for the inflammatory response. Emerging data reveal a new function of AQPs in the inflammatory process, as demonstrated by their dysregulation in a wide range of inflammatory diseases including edematous states, cancer, obesity, wound healing and several autoimmune diseases. This chapter summarizes the discoveries made so far about the structure and functions of the AQPs and provides updated information on the underlying mechanisms of AQPs in several human inflammatory diseases. The discovery of new functions for AQPs opens new vistas offering promise for the discovery of mechanisms and therapeutic opportunities in inflammatory disorders.
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Affiliation(s)
- Margherita Sisto
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs (SMBNOS), Section of Human Anatomy and Histology, University of Bari "Aldo Moro", Bari, Italy.
| | - Domenico Ribatti
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs (SMBNOS), Section of Human Anatomy and Histology, University of Bari "Aldo Moro", Bari, Italy
| | - Sabrina Lisi
- Department of Basic Medical Sciences, Neurosciences and Sensory Organs (SMBNOS), Section of Human Anatomy and Histology, University of Bari "Aldo Moro", Bari, Italy
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Mariotti V, Cadamuro M, Spirli C, Fiorotto R, Strazzabosco M, Fabris L. Animal models of cholestasis: An update on inflammatory cholangiopathies. Biochim Biophys Acta Mol Basis Dis 2018; 1865:954-964. [PMID: 30398152 DOI: 10.1016/j.bbadis.2018.07.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/18/2018] [Accepted: 07/19/2018] [Indexed: 12/21/2022]
Abstract
Cholestasis is a frequent clinical condition initiating or complicating chronic liver diseases, particularly cholangiopathies, where the biliary epithelium is the primary target of the pathogenetic sequence. Until a few decades ago, understanding of cholestasis relied mostly on the experimental model of bile duct ligation in rodents. However, a simple model of biliary obstruction cannot reproduce the complex mechanisms and networks leading to cholestasis in cholangiopathies. These networks are underpinned by an intricate dysregulation of pro-inflammatory and pro-fibrotic signals involving besides cholangiocytes, multiple cell elements of both innate and adaptive immunity. Therefore, in the last years, a wide range of animal models of biliary injury have been developed, mostly in mice, following three main approaches, chemical induction, immunization and genetic manipulation. In this review, we will give an update of the animal models of the two main cholangiopathies, primary sclerosing cholangitis and primary biliary cholangitis, which have provided us with the most relevant insights into the pathogenesis of these still controversial diseases.
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Affiliation(s)
- Valeria Mariotti
- Department of Molecular Medicine, University of Padua, Padua, Italy
| | | | - Carlo Spirli
- Section of Digestive Disease, Liver Center, Yale University, Yale, USA
| | - Romina Fiorotto
- Section of Digestive Disease, Liver Center, Yale University, Yale, USA
| | | | - Luca Fabris
- Department of Molecular Medicine, University of Padua, Padua, Italy; Section of Digestive Disease, Liver Center, Yale University, Yale, USA.
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Kirscht A, Sonntag Y, Kjellbom P, Johanson U. A structural preview of aquaporin 8 via homology modeling of seven vertebrate isoforms. BMC STRUCTURAL BIOLOGY 2018; 18:2. [PMID: 29454339 PMCID: PMC5816522 DOI: 10.1186/s12900-018-0081-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 01/25/2018] [Indexed: 11/10/2022]
Abstract
Background Aquaporins (AQPs) facilitate the passage of small neutral polar molecules across membranes of the cell. In animals there are four distinct AQP subfamilies, whereof AQP8 homologues constitute one of the smallest subfamilies with just one member in man. AQP8 conducts water, ammonia, urea, glycerol and H2O2 through various membranes of animal cells. This passive channel has been connected to a number of phenomena, such as volume change of mitochondria, ammonia neurotoxicity, and mitochondrial dysfunction related to oxidative stress. Currently, there is no experimentally determined structure of an AQP8, hence the structural understanding of this subfamily is limited. The recently solved structure of the plant AQP, AtTIP2;1, which has structural and functional features in common with AQP8s, has opened up for construction of homology models that are likely to be more accurate than previous models. Results Here we present homology models of seven vertebrate AQP8s. Modeling based on the AtTIP2;1 structure alone resulted in reasonable models except for the pore being blocked by a phenylalanine that is not present in AtTIP2;1. To achieve an open pore, these models were supplemented with models based on the bacterial water specific AQP, EcAqpZ, creating a chimeric monomeric model for each AQP8 isoform. The selectivity filter (also named the aromatic/arginine region), which defines the permeant substrate profile, comprises five amino acid residues in AtTIP2;1, including a histidine coming from loop C. Compared to AtTIP2;1, the selectivity filters of modelled AQP8s only deviates in that they are slightly more narrow and more hydrophobic due to a phenylalanine replacing the histidine from loop C. Interestingly, the models do not exclude the existence of a side pore beneath loop C similar to that described in the structure of AtTIP2;1. Conclusions Our models concur that AQP8s are likely to have an AtTIP2;1-like selectivity filter. The detailed description of the expected configuration of residues in the selectivity filters of AQP8s provides an excellent starting point for planning of as well as rationalizing the outcome of mutational studies. Our strategy to compile hybrid models based on several templates may prove useful also for other AQPs for which structural information is limited. Electronic supplementary material The online version of this article (10.1186/s12900-018-0081-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andreas Kirscht
- Division of Biochemistry and Structural Biology, Center for Molecular Protein Science, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden
| | - Yonathan Sonntag
- Division of Biochemistry and Structural Biology, Center for Molecular Protein Science, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden
| | - Per Kjellbom
- Division of Biochemistry and Structural Biology, Center for Molecular Protein Science, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden
| | - Urban Johanson
- Division of Biochemistry and Structural Biology, Center for Molecular Protein Science, Department of Chemistry, Lund University, Box 124, SE-221 00, Lund, Sweden.
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Rump K, Adamzik M. Function of aquaporins in sepsis: a systematic review. Cell Biosci 2018; 8:10. [PMID: 29449936 PMCID: PMC5807818 DOI: 10.1186/s13578-018-0211-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 02/02/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Sepsis is a common cause of death in intensive care units worldwide. Due to the high complexity of this immunological syndrome development of novel therapeutic strategies is urgent. Promising drug targets or biomarkers may depict aquaporins (AQPs) as they regulate crucial key mechanisms of sepsis. MAIN BODY Here we report on base of the current literature that several AQPs are involved in different physiological processes of sepsis. In immune system mainly AQPs 3, 5 and 9 seem to be important, as they regulate the migration of different immune cells. Several studies showed that AQP3 is essential for T cell function and macrophage migration and that AQP5 and AQP9 regulate neutrophil cell migration and impact sepsis survival. Additionally, to the function in immune system AQPs 1 and 5 play a role in sepsis induced lung injury and their downregulation after inflammatory stimuli impair lung injury. By contrast, AQP4 expression is up-regulated during brain inflammation and aggravates brain edema in sepsis. In kidney AQP2 expression is downregulated during sepsis and can cause renal failure. Some studies also suggest a role of AQP1 in cardiac function. CONCLUSION In conclusion, AQPs are involved in many physiological dysfunctions in sepsis and their expressions are differently regulated. Additional research on the regulatory mechanisms of aquaporins may identify potential therapeutic targets.
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Affiliation(s)
- Katharina Rump
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Knappschaftskrankenhaus Bochum-Langendreer, Ruhr-Universität Bochum, In der Schornau 23-25, 45882 Bochum, Germany
| | - Michael Adamzik
- Klinik für Anästhesiologie, Intensivmedizin und Schmerztherapie, Universitätsklinikum Knappschaftskrankenhaus Bochum-Langendreer, Ruhr-Universität Bochum, In der Schornau 23-25, 45882 Bochum, Germany
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Abstract
Aquaporins (AQPs ) are expressed in most exocrine and endocrine secretory glands. Consequently, summarizing the expression and functions of AQPs in secretory glands represents a daunting task considering the important number of glands present in the body, as well as the number of mammalian AQPs - thirteen. The roles played by AQPs in secretory processes have been investigated in many secretory glands. However, despite considerable research, additional studies are clearly needed to pursue our understanding of the role played by AQPs in secretory processes. This book chapter will focus on summarizing the current knowledge on AQPs expression and function in the gastrointestinal tract , including salivary glands, gastric glands, Duodenal Brunner's gland, liver and gallbladder, intestinal goblets cells, exocrine and endocrine pancreas, as well as few other secretory glands including airway submucosal glands, lacrimal glands, mammary glands and eccrine sweat glands.
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Affiliation(s)
- Christine Delporte
- Laboratory of Pathophysiological and Nutritional Biochemistry, Faculty of Medicine, Université Libre de Bruxelles, Brussels, Belgium.
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17
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Eshmuminov D, Tschuor C, Raptis DA, Boss A, Wurnig MC, Sergeant G, Schadde E, Clavien PA. Rapid liver volume increase induced by associating liver partition with portal vein ligation for staged hepatectomy (ALPPS): Is it edema, steatosis, or true proliferation? Surgery 2017; 161:1549-1552. [DOI: 10.1016/j.surg.2017.01.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 01/04/2017] [Accepted: 01/11/2017] [Indexed: 01/14/2023]
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Pelagalli A, Squillacioti C, Mirabella N, Meli R. Aquaporins in Health and Disease: An Overview Focusing on the Gut of Different Species. Int J Mol Sci 2016; 17:ijms17081213. [PMID: 27472320 PMCID: PMC5000611 DOI: 10.3390/ijms17081213] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/14/2016] [Accepted: 07/14/2016] [Indexed: 12/11/2022] Open
Abstract
Aquaporins (AQPs) play a pivotal role in gut homeostasis since their distribution and function is modulated both in physiological and in pathophysiological conditions. The transport of water and solutes through gut epithelia is essential for osmoregulation and digestive and absorptive functions. This passage is regulated by different AQP isoforms and characterized by their peculiar distribution in the gastrointestinal tract. To date, AQP localization has been identified in the gut and associated organs of several mammalian species by different techniques (immunohistochemical, western blotting, and RT-PCR). The present review describes the modulation of AQP expression, distribution, and function in gut pathophysiology. At the same time, the comparative description of AQP in animal species sheds light on the full range of AQP functions and the screening of their activity as transport modulators, diagnostic biomarkers, and drug targets. Moreover, the phenotype of knockout mice for several AQPs and their compensatory role and the use of specific AQP inhibitors have been also reviewed. The reported data could be useful to design future research in both basic and clinical fields.
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Affiliation(s)
- Alessandra Pelagalli
- Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via Pansini 5, 80131 Naples, Italy.
- Institute of Biostructures and Bioimages, National Research Council, Via De Amicis 95, 80131 Naples, Italy.
| | - Caterina Squillacioti
- Department of Veterinary Medicine and Animal Productions, University of Naples "Federico II", Via Veterinaria 1, 80137 Naples, Italy.
| | - Nicola Mirabella
- Department of Veterinary Medicine and Animal Productions, University of Naples "Federico II", Via Veterinaria 1, 80137 Naples, Italy.
| | - Rosaria Meli
- Department of Pharmacy, University of Naples "Federico II", Via D. Montesano 49, 80131 Naples, Italy.
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Poling HM, Mohanty SK, Tiao GM, Huppert SS. A comprehensive analysis of aquaporin and secretory related gene expression in neonate and adult cholangiocytes. Gene Expr Patterns 2014; 15:96-103. [PMID: 24929031 PMCID: PMC4283140 DOI: 10.1016/j.gep.2014.05.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2014] [Revised: 04/25/2014] [Accepted: 05/12/2014] [Indexed: 12/23/2022]
Abstract
Canalicular bile is secreted by hepatocytes and then passes through the intrahepatic bile ducts, comprised of cholangiocytes, to reach the extrahepatic biliary system. In addition to providing a conduit for bile to drain from the liver, cholangiocytes play an active role in modifying bile composition. Bile formation is the result of a series of highly coordinated intricate membrane-transport interactions. Proper systematic regulation of solute and water transport is critical for both digestion and the health of the liver, yet our knowledge of cholangiocyte water and ion transporters and their relative expression patterns remains incomplete. In this report, we provide a comprehensive expression profile of the aquaporin (AQP) family and three receptors/channels known to regulate ion transport in the murine cholangiocyte. In murine intrahepatic cholangiocytes, we found mRNA expression for all twelve of the members of the AQP family of proteins and found temporal changes in the expression profile occurring with age. Using AQP4, an established marker within cholangiocyte physiology, we found that AQP2, AQP5 and AQP6 expression levels to be significantly different between the neonatal and adult time points. Furthermore, there were distinct temporal expression patterns, with that of AQP12 unique in that its expression level decreased with age, whilst the majority of AQPs followed an increasing expression level trend with age. Of the three receptors/channels regulating ion transport in the murine cholangiocyte, only the cystic fibrosis transmembrane conductance regulator was found to follow a consistent trend of decreasing expression coincident with age. We have further validated AQP3 and AQP8 protein localization in both hepatocytes and cholangiocytes. This study emphasizes the need to further appreciate and consider the differences in cholangiocyte biology when treating neonatal and adult hepatobiliary diseases.
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Affiliation(s)
- Holly M Poling
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, United States.
| | - Sujit K Mohanty
- Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, United States.
| | - Greg M Tiao
- Division of Pediatric General and Thoracic Surgery, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, United States.
| | - Stacey S Huppert
- Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, United States.
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WILLERMAIN FRANÇOIS, JANSSENS SARAH, ARSENIJEVIC TATJANA, PIENS ISABELLE, BOLAKY NARGIS, CASPERS LAURE, PERRET JASON, DELPORTE CHRISTINE. Osmotic stress decreases aquaporin-4 expression in the human retinal pigment epithelial cell line, ARPE-19. Int J Mol Med 2014; 34:533-8. [DOI: 10.3892/ijmm.2014.1791] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 05/20/2014] [Indexed: 11/06/2022] Open
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Abstract
Bile is a unique and vital aqueous secretion of the liver that is formed by the hepatocyte and modified down stream by absorptive and secretory properties of the bile duct epithelium. Approximately 5% of bile consists of organic and inorganic solutes of considerable complexity. The bile-secretory unit consists of a canalicular network which is formed by the apical membrane of adjacent hepatocytes and sealed by tight junctions. The bile canaliculi (∼1 μm in diameter) conduct the flow of bile countercurrent to the direction of portal blood flow and connect with the canal of Hering and bile ducts which progressively increase in diameter and complexity prior to the entry of bile into the gallbladder, common bile duct, and intestine. Canalicular bile secretion is determined by both bile salt-dependent and independent transport systems which are localized at the apical membrane of the hepatocyte and largely consist of a series of adenosine triphosphate-binding cassette transport proteins that function as export pumps for bile salts and other organic solutes. These transporters create osmotic gradients within the bile canalicular lumen that provide the driving force for movement of fluid into the lumen via aquaporins. Species vary with respect to the relative amounts of bile salt-dependent and independent canalicular flow and cholangiocyte secretion which is highly regulated by hormones, second messengers, and signal transduction pathways. Most determinants of bile secretion are now characterized at the molecular level in animal models and in man. Genetic mutations serve to illuminate many of their functions.
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Affiliation(s)
- James L Boyer
- Department of Medicine and Liver Center, Yale University School of Medicine, New Haven, Connecticut, USA.
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22
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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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Wang JQ, Zhang L, Tao XG, Wei L, Liu B, Huang LL, Chen YG. Tetramethylpyrazine upregulates the aquaporin 8 expression of hepatocellular mitochondria in septic rats. J Surg Res 2013; 185:286-93. [DOI: 10.1016/j.jss.2013.05.106] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 05/26/2013] [Accepted: 05/31/2013] [Indexed: 12/17/2022]
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Daali Y, Millet P, Dayer P, Pastor CM. Evidence of Drug-Drug Interactions through Uptake and Efflux Transport Systems in Rat Hepatocytes: Implications for Cellular Concentrations of Competing Drugs. Drug Metab Dispos 2013; 41:1548-56. [DOI: 10.1124/dmd.113.051870] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Abstract
Sepsis-induced cholestasis is a complication of infection. Infections cause systemic and intrahepatic increase in proinflammatory cytokines which result in impaired bile flow ie. cholestasis. Several other mediators of impairment in bile flow have been identified under conditions of sepsis such as increased nitric oxide production and decreased aquaporin channels. The development of cholestasis may also further worsen inflammation. The molecular basis of normal bile flow and mechanisms of impairment in sepsis are discussed.
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Affiliation(s)
- Harjit K. Bhogal
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University School of Medicine, Richmond, VA
| | - Arun J. Sanyal
- Division of Gastroenterology, Hepatology and Nutrition, Virginia Commonwealth University School of Medicine, Richmond, VA
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Portincasa P, Calamita G. Water channel proteins in bile formation and flow in health and disease: when immiscible becomes miscible. Mol Aspects Med 2012; 33:651-64. [PMID: 22487565 DOI: 10.1016/j.mam.2012.03.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/29/2012] [Accepted: 03/31/2012] [Indexed: 12/19/2022]
Abstract
An essential function of the liver is the formation and secretion of bile, a complex aqueous solution of organic and inorganic compounds essential as route for the elimination of body cholesterol as unesterified cholesterol or as bile acids. In bile, a considerable amount of otherwise insoluble cholesterol is solubilized by carriers including two other classes of lipids, namely phospholipid and bile acids. Formation of bile and generation of bile flow are driven by the active secretion of bile acids, lipids and electrolytes into the canalicular and bile duct lumens followed by the parallel movement of water. Thus, water has to cross rapidly into and out of the cell interior driven by osmotic forces. Bile as a fluid, results from complicated interplay of hepatocyte and cholangiocyte uptake and secretion, concentration, by involving a number of transporters of lipids, anions, cations, and water. The discovery of the aquaporin water channels, has clarified the mechanisms by which water, the major component of bile (more than 95%), moves across the hepatobiliary epithelia. This review is focusing on novel acquisitions in liver membrane lipidic and water transport and functional participation of aquaporin water channels in multiple aspects of hepatobiliary fluid balance. Involvement of aquaporins in a series of clinically relevant hepatobiliary disorders are also discussed.
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Affiliation(s)
- Piero Portincasa
- University of Bari Medical School, Clinica Medica A. Murri, Department of Biomedical Sciences and Human Oncology, Policlinico Hospital, 70124 Bari, Italy.
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Lebeck J, Gena P, O'Neill H, Skowronski MT, Lund S, Calamita G, Praetorius J. Estrogen prevents increased hepatic aquaporin-9 expression and glycerol uptake during starvation. Am J Physiol Gastrointest Liver Physiol 2012; 302:G365-74. [PMID: 22114114 DOI: 10.1152/ajpgi.00437.2011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
In starvation, glycerol is released from adipose tissue and serves as an important precursor for hepatic gluconeogenesis. By unknown sex-specific mechanisms, women suppress the endogenous glucose production better than men and respond to metabolic stress with higher plasma glycerol levels. Hepatic glycerol uptake is facilitated by aquaporin-9 (AQP9), a broad-selectivity neutral solute channel, and represents an insulin-regulated step in supplying gluconeogenesis with glycerol. In the present study, hepatic AQP9 abundance was increased 2.6-fold in starved male rats as assessed by immunoblotting and immunohistochemistry. By contrast, starvation had no significant effect on hepatic AQP9 expression in female rats. Coordinately, plasma glycerol levels remained unchanged with starvation in male rats, whereas it was increased in female rats. The different responses to starvation were paralleled by higher glycerol permeability in basolateral hepatocyte membranes from starved male rats compared with starved females. Ovariectomy led to a starvation-response pattern identical to that observed in male rats with increased hepatic AQP9 expression and unchanged plasma glycerol levels. In cultured hepatocytes, 17β-estradiol and the selective estrogen receptor α-agonist, propyl pyrazole triol, caused a decrease in AQP9 expression. Our results support that a sex-specific regulation of the hepatic glycerol channel AQP9 during starvation contributes to the higher plasma glycerol levels observed in women during fasting and possibly results in a lower cytosolic availability of glycerol. Furthermore, the sexual dimorphism in the hepatic handling of glycerol during starvation might be explained by 17β-estradiol preventing the starvation-induced increase in hepatic AQP9 abundance.
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Affiliation(s)
- Janne Lebeck
- Dept. of Biomedicine, the Water and Salt Research Center, Aarhus Univ., Wilhelm Meyers Allé 3, DK-8000 Aarhus, Denmark.
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Millet P, Moulin M, Stieger B, Daali Y, Pastor CM. How Organic Anions Accumulate in Hepatocytes Lacking Mrp2: Evidence in Rat Liver. J Pharmacol Exp Ther 2011; 336:624-632. [DOI: 10.1124/jpet.110.175406] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
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