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Liu Y, Wu K, Fu Y, Li W, Zhao XY. Slc7a11 stimulates glutathione synthesis to preserve fatty acid metabolism in primary hepatocytes. Redox Rep 2023; 28:2260646. [PMID: 37750478 PMCID: PMC10540662 DOI: 10.1080/13510002.2023.2260646] [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] [Indexed: 09/27/2023] Open
Abstract
Primary hepatocytes are widely used as a tool for studying metabolic function and regulation in the liver. However, the metabolic properties of primary hepatocytes are gradually lost after isolation. Here, we illustrated that fatty acid metabolism is the major compromised metabolic process in isolated primary hepatocytes, along with drastically decreased GSH and ROS content, while lipid peroxidation is increased. Gain- and loss-of-function studies revealed that Slc7a11 expression is critical in maintaining fatty acid metabolism and facilitating hormone-induced fatty acid metabolic events, which is synergistic with dexamethasone treatment. Intriguingly, Slc7a11 expression and dexamethasone treatment cooperatively upregulated AKT and AMPK signaling and mitochondrial complex expression in primary hepatocytes. Furthermore, direct treatment with reduced GSH or inhibition of ferroptosis is sufficient to drive protective effects on fatty acid metabolism in primary hepatocytes. Our results demonstrate that Slc7a11 expression in isolated primary hepatocytes induces GSH production, which protects against ferroptosis, to increase fatty acid metabolic gene expression, AKT and AMPK signaling and mitochondrial function in synergy with dexamethasone treatment, thereby efficiently preserving primary hepatocyte metabolic signatures, thus providing a promising approach to better reserve primary hepatocyte metabolic activities after isolation to potentially improve the understanding of liver biological functions from studies using primary hepatocytes.
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Affiliation(s)
- Yifan Liu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Kaimin Wu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Yinkun Fu
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Wenyan Li
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
| | - Xu-Yun Zhao
- Department of Biochemistry and Molecular Cell Biology, Shanghai Key Laboratory for Tumor Microenvironment and Inflammation, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China
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Gajula SNR, Nadimpalli N, Sonti R. Drug metabolic stability in early drug discovery to develop potential lead compounds. Drug Metab Rev 2021; 53:459-477. [PMID: 34406889 DOI: 10.1080/03602532.2021.1970178] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Knowledge of the metabolic stability of a new drug substance eliminated by biotransformation is essential for envisaging the pharmacokinetic parameters required for deciding drug dosing and frequency. Strategies aimed at modifying lead compounds may improve metabolic stability, thereby reducing the drug dosing frequency. Replacement of selective hydrogens with deuterium can effectively enhance the drug's metabolic stability by increasing the biological half-life. Further, cyclization, change in ring size, and chirality can substantially improve the metabolic stability of drugs. The microsomal t1/2 approach for measuring drug in vitro intrinsic clearance by automated LC-MS/MS offers sensitive high-throughput screens with reliable data. The obtained in vitro intrinsic clearance from metabolic stability data helps predict the drug's in vivo total clearance using different scaling factors and hepatic clearance models. This review summarizes all the recent approaches and technological advancements in metabolic stability studies for narrowing down the potential lead compounds in drug discovery. Further, we summarized the potential pitfalls and assumptions made during the in vivo intrinsic clearance estimation from in vitro intrinsic clearance.
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Affiliation(s)
- Siva Nageswara Rao Gajula
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Nimisha Nadimpalli
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
| | - Rajesh Sonti
- Department of Pharmaceutical Analysis, National Institute of Pharmaceutical Education and Research (NIPER), Hyderabad, India
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3
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From in vivo to in vitro: Major metabolic alterations take place in hepatocytes during and following isolation. PLoS One 2017; 12:e0190366. [PMID: 29284039 PMCID: PMC5746264 DOI: 10.1371/journal.pone.0190366] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 12/13/2017] [Indexed: 12/20/2022] Open
Abstract
The liver plays a key role in maintaining physiological homeostasis and hepatocytes are largely responsible for this. The use of isolated primary hepatocytes has become an essential tool for the study of nutrient physiology, xenobiotic metabolism and several liver pathologies. Since hepatocytes are removed from their normal environment, the isolation procedure and in vitro culture of primary hepatocytes is partially known to induce undesired metabolic changes. We aimed to perform a thorough metabolic profiling of primary cells before, during and after isolation using state-of-the-art techniques. Extensive metabolite measurements using HPLC were performed in situ in the liver, during hepatocyte isolation using the two-step collagenase perfusion method and during in vitro cell culture for up to 48 hours. Assessment of mitochondrial respiratory capacity and ATP-linked respiration of isolated primary hepatocytes was performed using extracellular flux analysis. Primary hepatocytes displayed a drastic decrease in antioxidative-related metabolites (NADPH, NADP, GSH and GSSG) during the isolation procedure when compared to the in situ liver (P<0.001). Parallel assessment of citric acid cycle activity showed a significant decrease of up to 95% in Acetyl-CoA, Isocitrate/Citrate ratio, Succinate, Fumarate and Malate in comparison to the in situ liver (P<0.001). While the levels of several cellular energetic metabolites such as Adenosine, AMP, ADP and ATP were found to be progressively reduced during the isolation procedure and cell culture (P<0.001), higher ATP/ADP ratio and energy charge level were observed when primary cells were cultured in vitro compared to the in situ liver (P<0.05). In addition, a significant decrease in the respiratory capacity occurred after 24 hours in culture. Interestingly, this was not associated with a significant modification of ATP-linked respiration. In conclusion, major metabolic alterations occur immediately after hepatocytes are removed from the liver. These changes persist or increase during in vitro culture. These observations need to be taken into account when using primary hepatocytes for the study of metabolism or liver physiopathology.
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Zeigerer A, Wuttke A, Marsico G, Seifert S, Kalaidzidis Y, Zerial M. Functional properties of hepatocytes in vitro are correlated with cell polarity maintenance. Exp Cell Res 2017; 350:242-252. [DOI: 10.1016/j.yexcr.2016.11.027] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 11/28/2016] [Accepted: 11/30/2016] [Indexed: 12/16/2022]
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Davidson MD, Lehrer M, Khetani SR. Hormone and Drug-Mediated Modulation of Glucose Metabolism in a Microscale Model of the Human Liver. Tissue Eng Part C Methods 2015; 21:716-25. [PMID: 25517416 DOI: 10.1089/ten.tec.2014.0512] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Due to its central role in glucose homeostasis, the liver is an important target for drug development efforts for type 2 diabetes mellitus (T2DM). Significant differences across species in liver metabolism necessitate supplementation of animal data with assays designed to assess human-relevant responses. However, isolated primary human hepatocytes (PHHs) display a rapid decline in phenotypic functions in conventional monolayer formats. Cocultivation of PHHs with specific stromal cells, especially in micropatterned configurations, can stabilize some liver functions for ~4 weeks in vitro. However, it remains unclear whether coculture approaches can stabilize glucose metabolism that can be modulated with hormones in PHHs. Thus, in this study, we compared commonly employed conventional culture formats and previously developed micropatterned cocultures (MPCCs) of cryopreserved PHHs and stromal fibroblasts for mRNA expression of key glucose metabolism genes (i.e., phosphoenolpyruvate carboxykinase-1 [PCK1]) and sensitivity of gluconeogenesis to prototypical hormones, insulin and glucagon. We found that only MPCCs displayed high expression of all transcripts tested for at least 2 weeks and robust gluconeogenesis with responsiveness to hormones for at least 3 weeks in vitro. Furthermore, MPCCs displayed glycogen storage and lysis, which could be modulated with hormones under the appropriate feeding and fasting states, respectively. Finally, we utilized MPCCs in proof-of-concept experiments where we tested gluconeogenesis inhibitors and evaluated the effects of stimulation with high levels of glucose as in T2DM. Gluconeogenesis in MPCCs was decreased after stimulation with drugs (i.e., metformin) and the PHHs accumulated significant amount of lipids following incubation with excess glucose (i.e., 340% in 50 mM glucose relative to physiologic 5 mM glucose controls). In conclusion, MPCCs provide a platform to study glucose metabolism and hormonal responsiveness in cryopreserved PHHs from multiple donors for several weeks in vitro. This model is also useful to study the effects of drugs and overnutrition for applications in T2DM.
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Affiliation(s)
- Matthew D Davidson
- 1 School of Biomedical Engineering, Colorado State University , Fort Collins, Colorado
| | - Michael Lehrer
- 2 Department of Biomedical Sciences, Colorado State University , Fort Collins, Colorado
| | - Salman R Khetani
- 1 School of Biomedical Engineering, Colorado State University , Fort Collins, Colorado.,3 Department of Mechanical Engineering, Colorado State University , Fort Collins, Colorado
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Fraczek J, Bolleyn J, Vanhaecke T, Rogiers V, Vinken M. Primary hepatocyte cultures for pharmaco-toxicological studies: at the busy crossroad of various anti-dedifferentiation strategies. Arch Toxicol 2012; 87:577-610. [PMID: 23242478 DOI: 10.1007/s00204-012-0983-3] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 11/19/2012] [Indexed: 01/24/2023]
Abstract
Continuously increasing understanding of the molecular triggers responsible for the onset of diseases, paralleled by an equally dynamic evolution of chemical synthesis and screening methods, offers an abundance of pharmacological agents with a potential to become new successful drugs. However, before patients can benefit of newly developed pharmaceuticals, stringent safety filters need to be applied to weed out unfavourable drug candidates. Cost effectiveness and the need to identify compound liabilities, without exposing humans to unnecessary risks, has stimulated the shift of the safety studies to the earliest stages of drug discovery and development. In this regard, in vivo relevant organotypic in vitro models have high potential to revolutionize the preclinical safety testing. They can enable automation of the process, to match the requirements of high-throughput screening approaches, while satisfying ethical considerations. Cultures of primary hepatocytes became already an inherent part of the preclinical pharmaco-toxicological testing battery, yet their routine use, particularly for long-term assays, is limited by the progressive deterioration of liver-specific features. The availability of suitable hepatic and other organ-specific in vitro models is, however, of paramount importance in the light of changing European legal regulations in the field of chemical compounds of different origin, which gradually restrict the use of animal studies for safety assessment, as currently witnessed in cosmetic industry. Fortunately, research groups worldwide spare no effort to establish hepatic in vitro systems. In the present review, both classical and innovative methodologies to stabilize the in vivo-like hepatocyte phenotype in culture of primary hepatocytes are presented and discussed.
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Affiliation(s)
- J Fraczek
- Department of Toxicology, Faculty of Medicine and Pharmacy, Centre for Pharmaceutical Research, Vrije Universiteit Brussel, Belgium.
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Lu Y, Zhang G, Shen C, Uygun K, Yarmush ML, Meng Q. A novel 3D liver organoid system for elucidation of hepatic glucose metabolism. Biotechnol Bioeng 2011; 109:595-604. [PMID: 22006574 DOI: 10.1002/bit.23349] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 09/26/2011] [Accepted: 09/29/2011] [Indexed: 12/12/2022]
Abstract
Hepatic glucose metabolism is a key player in diseases such as obesity and diabetes as well as in antihyperglycemic drugs screening. Hepatocytes culture in two-dimensional configurations is limited in vitro model for hepatocytes to function properly, while truly practical platforms to perform three-dimensional (3D) culture are unavailable. In this work, we present a practical organoid culture method of hepatocytes for elucidation of glucose metabolism under nominal and stress conditions. Employing this new method of culturing cells within a hollow fiber reactor, hepatocytes were observed to self-assemble into 3D spherical organoids with preservation of tight junctions and display increased liver-specific functions. Compared to both monolayer culture and sandwich culture, the hepatocyte organoids displayed higher intracellular glycogen content, glucose consumption, and gluconeogenesis and approached the in vivo values, as also confirmed by gene expression of key enzymes. Moreover, hepatocyte organoids demonstrated more realistic sensitivity to hormonal challenges with insulin, glucagon, and dexamethasone. Finally, the exposure to high glucose demonstrated toxicities including alteration of mitochondrial membrane potential, lipid accumulation, and reactive oxygen species formation, similar to the in vivo responses, which was not captured by monolayer cultures. Collectively, hepatocyte organoids mimicked the in vivo functions better than hepatocyte monolayer and sandwich cultures, suggesting suitability for applications such as antihyperglycemic drugs screening.
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Affiliation(s)
- Yanhua Lu
- Department of Chemical and Biological Engineering, Zhejiang University, 38 Zheda Road, Hangzhou, Zhejiang 310027, China
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Abstract
In vitro drug metabolism studies, which are inexpensive and readily carried out, serve as an adequate screening mechanism to characterize drug metabolites, elucidate their pathways, and make suggestions for further in vivo testing. This publication is a sequel to part I in a series and aims at providing a general framework to guide designs and protocols of the in vitro drug metabolism studies considered good practice in an efficient manner such that it would help researchers avoid common pitfalls and misleading results. The in vitro models include hepatic and non-hepatic microsomes, cDNA-expressed recombinant human CYPs expressed in insect cells or human B lymphoblastoid, chemical P450 inhibitors, S9 fraction, hepatocytes and liver slices. Important conditions for conducting the in vitro drug metabolism studies using these models are stated, including relevant concentrations of enzymes, co-factors, inhibitors and test drugs; time of incubation and sampling in order to establish kinetics of reactions; appropriate control settings, buffer selection and method validation. Separate in vitro data should be logically integrated to explain results from animal and human studies and to provide insights into the nature and consequences of in vivo drug metabolism. This article offers technical information and data and addresses scientific rationales and practical skills related to in vitro evaluation of drug metabolism to meet regulatory requirements for drug development.
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Affiliation(s)
- Lee Jia
- Toxicology & Pharmacology Branch, Developmental Therapeutics Program, National Cancer Institute, NIH, Rockville, MD 20852, USA.
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Hewitt NJ, Lechón MJG, Houston JB, Hallifax D, Brown HS, Maurel P, Kenna JG, Gustavsson L, Lohmann C, Skonberg C, Guillouzo A, Tuschl G, Li AP, LeCluyse E, Groothuis GMM, Hengstler JG. Primary hepatocytes: current understanding of the regulation of metabolic enzymes and transporter proteins, and pharmaceutical practice for the use of hepatocytes in metabolism, enzyme induction, transporter, clearance, and hepatotoxicity studies. Drug Metab Rev 2007; 39:159-234. [PMID: 17364884 DOI: 10.1080/03602530601093489] [Citation(s) in RCA: 523] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This review brings you up-to-date with the hepatocyte research on: 1) in vitro-in vivo correlations of metabolism and clearance; 2) CYP enzyme induction, regulation, and cross-talk using human hepatocytes and hepatocyte-like cell lines; 3) the function and regulation of hepatic transporters and models used to elucidate their role in drug clearance; 4) mechanisms and examples of idiosyncratic and intrinsic hepatotoxicity; and 5) alternative cell systems to primary human hepatocytes. We also report pharmaceutical perspectives of these topics and compare methods and interpretations for the drug development process.
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Affiliation(s)
- Nicola J Hewitt
- Scientific Writing Services, Wingertstrasse, Erzhausen, Germany.
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Turncliff RZ, Meier PJ, Brouwer KLR. EFFECT OF DEXAMETHASONE TREATMENT ON THE EXPRESSION AND FUNCTION OF TRANSPORT PROTEINS IN SANDWICH-CULTURED RAT HEPATOCYTES. Drug Metab Dispos 2004; 32:834-9. [PMID: 15258109 DOI: 10.1124/dmd.32.8.834] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Dexamethasone (DEX) is a well established inducer of CYP3A. These studies examined the influence of DEX treatment on transport protein expression and function in sandwich-cultured (SC) rat hepatocytes. Freshly isolated hepatocytes were cultured between two layers of gelled collagen and maintained in Dulbecco's modified Eagle's medium supplemented with DEX (0.1 microM, 0-48 h and 0.1-100 microM, 48-96 h). The expression of sinusoidal [(organic anion transporting polypeptide 1a1 (Oatp1a1), Oatp1a4, multidrug resistance-associated protein 3 (Mrp3), and Na(+)-dependent taurocholate cotransporting polypeptide (Ntcp)] and canalicular [bile salt export pump (Bsep), multidrug resistance protein 1a/b (Mdr1a/b), and Mrp2] transport proteins was determined by Western blot analysis. The accumulation and biliary excretion index (BEI; percentage of accumulated substrate in canalicular networks) of the probe substrates taurocholate (TC; 1 microM, 10 min), rhodamine 123 (Rh123; 10 microM, 30 min), and carboxy-2',7'-dichlorofluorescein (CDF; 10 microM, 10 min) were employed as measures of canalicular transport protein function in SC rat hepatocytes. DEX treatment increased CYP3A1/2, Oatp1a4, and Mrp2 expression, decreased the expression of Ntcp, and did not seem to alter the expression of Oatp1a1, Mrp3, Mdr1a/b, or Bsep. The BEI of CDF, an Mrp2 substrate, increased from 18 to 37% after DEX treatment (100 microM). The accumulation of TC, an Ntcp substrate, was reduced (<50% of control), whereas the BEI of TC, also a Bsep substrate, was unchanged. Treatment of SC rat hepatocytes with DEX resulted in alterations in the expression of CYP3A1/2 and some hepatic transport proteins. Modest alterations in hepatic transport protein function were consistent with changes in protein expression.
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Affiliation(s)
- Ryan Z Turncliff
- Division of Drug Delivery and Disposition, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7360, USA
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Luttringer O, Theil FP, Lavé T, Wernli-Kuratli K, Guentert TW, de Saizieu A. Influence of isolation procedure, extracellular matrix and dexamethasone on the regulation of membrane transporters gene expression in rat hepatocytes. Biochem Pharmacol 2002; 64:1637-50. [PMID: 12429353 DOI: 10.1016/s0006-2952(02)01382-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The influence of the isolation procedure of hepatocytes, extracellular matrix (ECM) configuration and incubation medium supplementation by dexamethasone (DEX) on the cell morphology and on the gene expression of membrane transporters was examined in rat hepatocytes. The mRNA levels were determined using oligonucleotide microarrays, in liver, in suspension and in primary culture in monolayer (CPC), and in collagen gels sandwich (SPC) in absence and presence of DEX (100 and 1000 nM). The results indicated pronounced morphological differences between CPC and SPC in response to DEX demonstrating that the hepatocytes re-formed, as in vivo, multicellular arrays with extensive bile canalicular network only in SPC in presence of DEX. The mRNA levels of membrane transporters were not affected significantly during isolation procedure. However, plating hepatocytes in CPC resulted in a decrease of major basolateral transporters mRNA level whereas mRNA levels of mdr1b and mrp3 were increased (>100-fold). Similar observations were made in SPC in the absence of DEX demonstrating that the ECM configuration alone did not play a critical role in the regulation of membrane transporters. However, adding DEX to the incubation medium in SPC resulted in an up-regulation of mdr2, oatp2 and mrp2 in a concentration-dependent way for the two latter genes, whereas mdr1b and mrp3 expression were maintained to their baseline liver levels. These data suggested therefore that the combination of ECM and DEX supplementation is essential for the formation of the bile canalicular network and is a determinant factor in the regulation of membrane transporters in cultured rat hepatocytes.
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Ferraris M, Radice S, Catalani P, Francolini M, Marabini L, Chiesara E. Early oxidative damage in primary cultured trout hepatocytes: a time course study. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2002; 59:283-296. [PMID: 12127742 DOI: 10.1016/s0166-445x(02)00007-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The aim of this study was to evaluate the influence of the two-step hepatocyte isolation procedure on primary cultured trout (Oncorhynchus mykiss) hepatocytes over time. We characterised the possible changes of a variety of some cellular parameters within the first 24-48 h after seeding. We followed the time dependent changes of these parameters during subsequent culture times in order to see if the cells maintained a differentiated status. Scanning electron microscopy revealed bleb formation and 20% cell damage in freshly isolated hepatocytes. During subsequent culture times the bleb dimension appear to be reduced. Heat shock proteins 70 and 50 (HSP70, HSP50) were induced by hepatocyte isolation. During the first 4 h of culture, the hepatocytes showed a variation in mitochondrial activity, an increase in free radical species (ROS), and a decrease in both glutathione (GSH) content and catalase (CAT) activity; the generation of free radicals led to an increase in the formation of 8-hydroxydeoxyguanosine (8-OHdG) in the DNA. The cells showed detectable ethoxyresorufin-O-deethylase activity after 4 h of culture, which had rapidly increased by the 24th hour. After 24 h, mitochondrial and CAT activity, free radical production, and the content of GSH and 8-OHdG returned to their original levels. P450 activity was retained for at least 48 h after seeding. Our data show that trout hepatocytes suffer significant cell injury as a result of the isolation procedure, but primary cultured cells metabolically recover from this stress after a few hours: they are capable of repairing their damaged surfaces, recovering their antioxidant defences and retaining their ability to repair DNA. Our results also confirm that trout hepatocytes in a primary culture maintain their in vivo-like metabolic activities for 3-8 days.
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Affiliation(s)
- Michela Ferraris
- Department of Pharmacology, Chemotherapy and Medical Toxicology E. Trabucchi, University of Milan, Via Vanvitelli 32, Milan, Italy.
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Jitrapakdee S, Gong Q, MacDonald MJ, Wallace JC. Regulation of rat pyruvate carboxylase gene expression by alternate promoters during development, in genetically obese rats and in insulin-secreting cells. Multiple transcripts with 5'-end heterogeneity modulate translation. J Biol Chem 1998; 273:34422-8. [PMID: 9852109 DOI: 10.1074/jbc.273.51.34422] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A previous study on the gene structure of rat pyruvate carboxylase revealed that two tissue-specific promoters are responsible for the production of multiple transcripts with 5'-end heterogeneity (Jitrapakdee, S., Booker, G. W., Cassady, A. I., and Wallace, J. C. (1997) J. Biol. Chem. 272, 20522-20530). Here we report transcription and translation regulation of pyruvate carboxylase (PC) expression during development and in genetically obese rats. The abundance of PC mRNAs was low in fetal liver but increased by 2-4-fold within 7 days after birth, concomitant with an 8-fold increase in the amount of immunoreactive PC and its activity and then decreased during the weaning period. Reverse transcriptase polymerase chain reaction analysis indicated that the proximal promoter was activated during the suckling period and reduced in activity at weaning. In genetically obese Zucker rats, adipose PC was 4-5-fold increased, concomitant with a 5-6-fold increase in mRNA level. Reverse transcriptase-polymerase chain reaction analysis also showed that the proximal promoter was activated in the hyperlipogenic condition. Conversely, transcription of the proximal promoter was not detectable in various liver cell lines, suggesting that this promoter was not functional under cell culture conditions. In rat pancreatic islets and insulinoma cells, only transcripts D and E, generated from the distal promoter of the PC gene, were expressed. Glucose increased PC transcripts from the distal promoter when the insulinoma cells were maintained in 10 mM glucose. We conclude that the proximal promoter of the rat PC gene plays a major role in gluconeogenesis and lipogenesis, whereas the distal promoter is necessary for anaplerosis. In vitro translation and in vivo polysome profile analysis indicated that transcripts C and E were translated with similar translational efficiencies that are substantially greater than that of transcript D, suggesting that 5'-untranslated regions play a role in translational control.
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Affiliation(s)
- S Jitrapakdee
- Department of Biochemistry, University of Adelaide, Adelaide, South Australia 5005, Australia
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LeCluyse EL, Bullock PL, Parkinson A. Strategies for restoration and maintenance of normal hepatic structure and function in long-term cultures of rat hepatocytes. Adv Drug Deliv Rev 1996. [DOI: 10.1016/s0169-409x(96)00418-8] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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LeCluyse EL, Bullock PL, Parkinson A, Hochman JH. Cultured rat hepatocytes. PHARMACEUTICAL BIOTECHNOLOGY 1996; 8:121-59. [PMID: 8791809 DOI: 10.1007/978-1-4899-1863-5_9] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- E L LeCluyse
- INTERx Research/Merck Research Laboratories, Lawrence, Kansas 66047, USA
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16
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Segner H, Blair JB, Wirtz G, Miller MR. Cultured trout liver cells: utilization of substrates and response to hormones. In Vitro Cell Dev Biol Anim 1994; 30A:306-11. [PMID: 8069456 DOI: 10.1007/bf02631451] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The characterization of a recently established system for the short-term culture of rainbow trout (Oncorhynchus mykiss) liver cells in chemically defined medium has been extended to studies on the metabolic competence of the cells and the characterization of their response to hormones. Three areas of metabolism have been addressed: a) the utilization of the exogenously added substrates fructose, lactate, glucose, dihydroxyacetone, and glycerol for glucose and lactate formation; b) the effects of the pancreatic hormones insulin and glucagon on cellular glucose formation, lactate formation, and fatty acid synthesis; and c) the effects of insulin and dexamethasone on the estradiol-dependent production of vitellogenin. Incubation of trout liver cells with fructose, lactate, glucose, dihydroxyacetone, or glycerol resulted in enhanced rates of cellular glucose and lactate production. Substrate-induced effects usually were more clearly expressed after extended (20 h) than after acute (5 h) culture periods. Addition of the hormones insulin or glucagon caused dose-dependent alterations in the flux of substrates to glucose and lactate. Rates of de novo synthesis of fatty acids from [14C]acetate were stimulated by insulin and inhibited by glucagon during acute and extended incubation periods. Treatment of liver cells isolated from male trout for 72 h with estradiol induced vitellogenin production and secretion into the medium. However, the addition of insulin or dexamethasone drastically reduced this estrogen-induced vitellogenesis. These results indicate that trout liver cells cultured in defined medium maintain central metabolic pathways, including glycolysis, gluconeogenesis, lipogenesis, and vitellogenesis as well as their responsiveness to various hormones, for at least 72 h.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- H Segner
- Department of Zoology II, University of Karlsruhe, FRG
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17
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Innes GK, Fuller BJ, Hobbs KE. Lipid peroxidation in hepatocyte cell cultures: modulation by free radical scavengers and iron. IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY : JOURNAL OF THE TISSUE CULTURE ASSOCIATION 1988; 24:126-32. [PMID: 3125142 DOI: 10.1007/bf02623889] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Rat hepatocytes were isolated and then maintained in serum-free cell culture medium for 24 h. The amount of malondialdehyde (MDA) accumulated in the medium was assayed and used as a measure of lipid peroxidation. The activity of lactate dehydrogenase (LDH) and urea were measured in the medium and used as indicators of hepatocellular viability and function. The effects of iron; desferrioxamine mesylate (Desferal), an iron chelator; and mannitol, a hydroxyl free radical scavenger were investigated. The addition of iron, Fe2 resulted in a three-fold increase in the levels of MDA. Desferal inhibited the production of MDA and blocked the effect of Fe2+. Neither iron nor Desferal had any effect on LDH or urea levels. Mannitol had no effect on MDA or urea production, but caused a 4 to 8-fold increase in the LDH levels in the medium. The results show that iron is involved in the mechanism of lipid peroxidation in hepatocyte cultures but suggest that as a pathologic event lipid peroxidation is not expressed in terms of viability during the first 24 h of hepatocyte culture.
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Affiliation(s)
- G K Innes
- Academic Department of Surgery, Royal Free Hospital School of Medicine, London, UK
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Suleiman SA, Stevens JB. The effect of oxygen tension on rat hepatocytes in short-term culture. IN VITRO CELLULAR & DEVELOPMENTAL BIOLOGY : JOURNAL OF THE TISSUE CULTURE ASSOCIATION 1987; 23:332-8. [PMID: 3583984 DOI: 10.1007/bf02620989] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell viability, cytochrome P-450 content, cell respiration, and lipid peroxidation were all investigated as a function of oxygen tension in adult rat hepatocytes in short-term culture (less than 9 h). The various oxygen tensions used in this study were obtained by equilibrating culture medium with air, air + nitrogen, or air + oxygen. Cell viability, as assessed by trypan blue exclusion, was significantly greater at all time points tested when hepatocytes were cultured in Ham's F12 medium containing 132 microM O2, as compared to medium equilibrated with air (220 microM O2) or air + oxygen (298 microM O2). Cells cultured in 220 microM O2 (air) also exhibited a gradual loss of cytochrome P-450, so that by 9 h of incubation less than 60% of the active material remained. This loss of P-450 was minimized when cells were cultured in 163 microM O2 and abolished when cells were cultured in 132 microM O2. The 132 microM O2 exposure conditions also maintained cell respiration at the 1 h incubation values, whereas there was a continuous loss in cell respiration over time when the cells were cultured in either 220 microM O2 (air) or 298 microM O2 (air:O2). These cytotoxicity findings may be related to oxidative cell damage inasmuch as it was additionally demonstrated that lipid peroxidation (as measured by malondieldehyde equivalents) was consistantly lower in hepatocytes cultured in air:N2 as compared to air or air:O2. These results suggest that hepatocyte culture in low oxygen tension improves not only cell viability but also maintains other functional characteristics of the cell.
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Edwards AM, Baddams HM, Lucas CM. Two distinct mechanisms for regulation of gamma-glutamyl transpeptidase in cultured rat hepatocytes by glucocorticoid-like steroids. Biochem Pharmacol 1987; 36:1223-30. [PMID: 2885003 DOI: 10.1016/0006-2952(87)90074-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Adult rat hepatocytes maintained in primary monolayer culture with defined medium were used to characterise two effects of glucocorticoid-like steroids in regulating gamma-glutamyltranspeptidase (GGT). Low concentrations of glucocorticoids alone had little effect on GGT but synergistically enhanced induction of the enzyme by liver tumor-promoting xenobiotics such as 1,1,1-trichloro-2,2-bis-(4-chlorophenyl)-ethane (DDT) and hexachlorocyclohexane. The enhancing effect appears to be mediated by the classical glucocorticoid hormone receptor since structural requirements and concentration-dependence for enhancement were similar to those for induction of tyrosine aminotransferase in parallel cultures. Higher concentrations (1-100 microM) of various glucocorticoids alone increased GGT activity. Most glucocorticoids induced GGT but their order of potency did not parallel that for induction of tyrosine aminotransferase under similar culture conditions. Among the most potent glucocorticoids, triamcinolone was a weak GGT inducer and cortivazol appeared to act as an antagonist of GGT induction by steroids. Some non-glucocorticoids including pregnenolone 16 alpha-carbonitrile, and some progestins, also induced but required addition of 30 nM dexamethasone for maximal effect. Some specific steroid structural features were identified which increased (presence of a 16 alpha methyl group) or impaired GGT-inducing activity. Although interpretation is complicated by differential metabolism of individual steroids in culture, the results suggest that GGT induction by pharmacological levels of steroids may be mediated, directly or indirectly, by one or more relatively specific receptors distinct from the classical glucocorticoid receptor.
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Flaim KE, Hutson SM, Lloyd CE, Taylor JM, Shiman R, Jefferson LS. Direct effect of insulin on albumin gene expression in primary cultures of rat hepatocytes. THE AMERICAN JOURNAL OF PHYSIOLOGY 1985; 249:E447-53. [PMID: 3904479 DOI: 10.1152/ajpendo.1985.249.5.e447] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The purpose of this study was to identify a cell culture system in which the role of insulin in regulating albumin gene expression could be investigated. The system selected was rat hepatocytes maintained in primary culture in a chemically defined, serum-free medium. Under control conditions albumin secretion was nearly the same as the rate recorded in vivo and in perfused liver and was reasonably well maintained during 8 days of culture. Deletion of insulin from the culture medium for 3-6 days resulted in 40-60% reductions in albumin secretion. Furthermore, albumin secretion relative to the rate of total protein synthesis was reduced by approximately 50% as a result of insulin deficiency. Readdition of the hormone to insulin-deficient cultures restored secretion to the control rate. A maximal effect of insulin was observed within 3 days after readdition of the hormone, and a half-maximal response was obtained with a hormone concentration of approximately 3.0 nM. The relative abundance of albumin mRNA, as measured by solution hybridization using a complementary DNA probe, responded in a parallel fashion to the changes in albumin secretion. Thus rat hepatocytes maintained under appropriate culture conditions reflect the effects of diabetes and insulin treatment on albumin gene expression observed in vivo and provide an excellent model system in which to study the mechanism(s) of insulin action.
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Auberger P, Le Cam A. Comparative analysis of proteins labelled with [35S]methionine in the liver in vivo and in freshly isolated and short-term-cultured hepatocytes in vitro. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 718:92-102. [PMID: 6753943 DOI: 10.1016/0304-4165(82)90013-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
[35S]Methionine-labelled liver proteins, analysed by one- or two-dimensional gel electrophoresis showed a strikingly similar pattern whether synthesized in vivo or by freshly isolated hepatocytes. In contrast, major qualitative and quantitative differences were observed with the patterns of labelled proteins found in cultured hepatocytes. The changes detectable very early (within 1 h) in culture affected preferentially the synthesis of cytoskeleton proteins (cytokeratins, actin, myosin), which was dramatically increased. Physical factors like cell attachment appear to be responsible for these changes which, however, occurred more rapidly in the presence of serum. Freshly isolated hepatocytes and short-term-cultured cells responded similarly to insulin and glucagon, which respectively increased and decreased the labelling of the whole set of cellular and exported proteins. Glucocorticoids caused either an increase or a decrease in the labelling of several proteins, but the effects were detectable only under chronic exposure of cultured hepatocytes. Based on these results, freshly isolated hepatocytes appear more representative of the liver in vivo than cultured hepatocytes, and therefore seem more suitable for short-term studies. However, cultured hepatocytes can be used for long-term studies since they maintain many specific liver functions and remain hormonally sensitive.
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Rosenberg MR, Strom SC, Michalopoulos G. Effect of hydrocortisone and nicotinamide on gamma glutamyltransferase in primary cultures of rat hepatocytes. IN VITRO 1982; 18:775-82. [PMID: 6129190 DOI: 10.1007/bf02796501] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Isolated rat hepatocytes cultured on collagen coated plates exhibit a gradual fetal phenotypic change during time in culture. The fetal liver marker gamma glutamyltransferase (GGT) was used to follow this change. Inasmuch as a significant overgrowth of nonparenchymal liver derived cells is seen frequently in primary cultures of hepatocytes, a technique was utilized that corrects for the presence of nonparenchymal cells. In media supplemented with either hydrocortisone (10(-5) M) or nicotinamide (25 mM) the original epithelial morphology of hepatocytes was preserved for a longer period of time than in unsupplemented media. Hepatocytes in unsupplemented media exhibited an increase in GGT specific activity over time. Hydrocortisone (10(-5) M) induced an increase in GGT activity compared to controls. Nicotinamide (25 mM) inhibited the increase in GGT activity compared to the unsupplemented hepatocytes. Our results indicate that GGT is regulated by hydrocortisone and nicotinamide.
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