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Garcia-Llorens G, Martínez-Sena T, Pareja E, Tolosa L, Castell JV, Bort R. A robust reprogramming strategy for generating hepatocyte-like cells usable in pharmaco-toxicological studies. Stem Cell Res Ther 2023; 14:94. [PMID: 37072803 PMCID: PMC10114490 DOI: 10.1186/s13287-023-03311-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 03/28/2023] [Indexed: 04/20/2023] Open
Abstract
BACKGROUND High-throughput pharmaco-toxicological testing frequently relies on the use of established liver-derived cell lines, such as HepG2 cells. However, these cells often display limited hepatic phenotype and features of neoplastic transformation that may bias the interpretation of the results. Alternate models based on primary cultures or differentiated pluripotent stem cells are costly to handle and difficult to implement in high-throughput screening platforms. Thus, cells without malignant traits, optimal differentiation pattern, producible in large and homogeneous amounts and with patient-specific phenotypes would be desirable. METHODS We have designed and implemented a novel and robust approach to obtain hepatocytes from individuals by direct reprogramming, which is based on a combination of a single doxycycline-inducible polycistronic vector system expressing HNF4A, HNF1A and FOXA3, introduced in human fibroblasts previously transduced with human telomerase reverse transcriptase (hTERT). These cells can be maintained in fibroblast culture media, under standard cell culture conditions. RESULTS Clonal hTERT-transduced human fibroblast cell lines can be expanded at least to 110 population doublings without signs of transformation or senescence. They can be easily differentiated at any cell passage number to hepatocyte-like cells with the simple addition of doxycycline to culture media. Acquisition of a hepatocyte phenotype is achieved in just 10 days and requires a simple and non-expensive cell culture media and standard 2D culture conditions. Hepatocytes reprogrammed from low and high passage hTERT-transduced fibroblasts display very similar transcriptomic profiles, biotransformation activities and show analogous pattern behavior in toxicometabolomic studies. Results indicate that this cell model outperforms HepG2 in toxicological screening. The procedure also allows generation of hepatocyte-like cells from patients with given pathological phenotypes. In fact, we succeeded in generating hepatocyte-like cells from a patient with alpha-1 antitrypsin deficiency, which recapitulated accumulation of intracellular alpha-1 antitrypsin polymers and deregulation of unfolded protein response and inflammatory networks. CONCLUSION Our strategy allows the generation of an unlimited source of clonal, homogeneous, non-transformed induced hepatocyte-like cells, capable of performing typical hepatic functions and suitable for pharmaco-toxicological high-throughput testing. Moreover, as far as hepatocyte-like cells derived from fibroblasts isolated from patients suffering hepatic dysfunctions, retain the disease traits, as demonstrated for alpha-1-antitrypsin deficiency, this strategy can be applied to the study of other cases of anomalous hepatocyte functionality.
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Affiliation(s)
- Guillem Garcia-Llorens
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, Torre A. Lab 6.08, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Valencia, Spain
| | - Teresa Martínez-Sena
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, Torre A. Lab 6.08, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
| | - Eugenia Pareja
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, Torre A. Lab 6.08, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Servicio de Cirugía General y Aparato Digestivo, Hospital Universitario Dr. Peset, Valencia, Spain
| | - Laia Tolosa
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, Torre A. Lab 6.08, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Centro de Investigación Biomédica en Red de Bioingenieria, Biomateriales y Nanomedicina (CIBER-Bbn), Instituto de Salud Carlos III, Madrid, Spain
| | - José V Castell
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, Torre A. Lab 6.08, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain
- Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Valencia, Spain
| | - Roque Bort
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, Torre A. Lab 6.08, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, Madrid, Spain.
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Garcia-Llorens G, Lopez-Navarro S, Jaijo T, Castell JV, Bort R. Modeling a Novel Variant of Glycogenosis IXa Using a Clonal Inducible Reprogramming System to Generate "Diseased" Hepatocytes for Accurate Diagnosis. J Pers Med 2022; 12:jpm12071111. [PMID: 35887608 PMCID: PMC9322025 DOI: 10.3390/jpm12071111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/01/2022] [Accepted: 07/05/2022] [Indexed: 11/16/2022] Open
Abstract
The diagnosis of inherited metabolic disorders is a long and tedious process. The matching of clinical data with a genomic variant in a specific metabolic pathway is an essential step, but the link between a genome and the clinical data is normally difficult, primarily for new missense variants or alterations in intron sequences. Notwithstanding, elucidation of the pathogenicity of a specific variant might be critical for an accurate diagnosis. In this study, we described a novel intronic variant c.2597 + 5G > T in the donor splice sequence of the PHKA2 gene. To investigate PHKA2 mRNA splicing, as well as the functional consequences on glycogen metabolism, we generated hepatocyte-like cells from a proband’s fibroblasts by direct reprogramming. We demonstrated an aberrant splicing of PHKA2, resulting in the incorporation of a 27 bp upstream of intron 23 into exon 23, which leads to an immediate premature STOP codon. The truncated protein was unable to phosphorylate the PYGL protein, causing a 4-fold increase in the accumulation of glycogen in hepatocyte-like cells. Collectively, the generation of personalized hepatocyte-like cells enabled an unequivocal molecular diagnosis and qualified the sister’s proband, a carrier of the same mutation, as a candidate for a preimplantation genetic diagnosis. Additionally, our direct reprogramming strategy allows for an unlimited source of “diseased” hepatocyte-like cells compatible with high-throughput platforms.
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Affiliation(s)
- Guillem Garcia-Llorens
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, 46026 Valencia, Spain; (G.G.-L.); (S.L.-N.); (J.V.C.)
- Biochemistry and Molecular Biology Department, Universidad de Valencia, 46026 Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Sergi Lopez-Navarro
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, 46026 Valencia, Spain; (G.G.-L.); (S.L.-N.); (J.V.C.)
| | - Teresa Jaijo
- Molecular, Cellular and Genomic Biomedicine, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, 46026 Valencia, Spain;
| | - Jose V. Castell
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, 46026 Valencia, Spain; (G.G.-L.); (S.L.-N.); (J.V.C.)
- Biochemistry and Molecular Biology Department, Universidad de Valencia, 46026 Valencia, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Roque Bort
- Unidad de Hepatología Experimental y Trasplante Hepático, Instituto de Investigación Sanitaria La Fe, Hospital Universitario y Politecnico La Fe, 46026 Valencia, Spain; (G.G.-L.); (S.L.-N.); (J.V.C.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-961-246-621
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Santamaria R, Ballester M, Garcia-Llorens G, Martinez F, Blazquez M, Ribes-Koninckx C, Castell JV, Wuestefeld T, Bort R. Derivation of healthy hepatocyte-like cells from a female patient with ornithine transcarbamylase deficiency through X-inactivation selection. Sci Rep 2022; 12:2308. [PMID: 35145162 PMCID: PMC8831560 DOI: 10.1038/s41598-022-06184-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 01/18/2022] [Indexed: 11/09/2022] Open
Abstract
Autologous cell replacement therapy for inherited metabolic disorders requires the correction of the underlying genetic mutation in patient's cells. An unexplored alternative for females affected from X-linked diseases is the clonal selection of cells randomly silencing the X-chromosome containing the mutant allele, without in vivo or ex vivo genome editing. In this report, we have isolated dermal fibroblasts from a female patient affected of ornithine transcarbamylase deficiency and obtained clones based on inactivation status of either maternally or paternally inherited X chromosome, followed by differentiation to hepatocytes. Hepatocyte-like cells derived from these clones display indistinct features characteristic of hepatocytes, but express either the mutant or wild type OTC allele depending on X-inactivation pattern. When clonally derived hepatocyte-like cells were transplanted into FRG® KO mice, they were able to colonize the liver and recapitulate OTC-dependent phenotype conditioned by X-chromosome inactivation pattern. This approach opens new strategies for cell therapy of X-linked metabolic diseases and experimental in vitro models for drug development for such diseases.
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Affiliation(s)
- Ramon Santamaria
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
| | - Maria Ballester
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
| | - Guillem Garcia-Llorens
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Biochemistry and Molecular Biology Department, Universidad de Valencia, Valencia, Spain
| | - Francisco Martinez
- Genetics Unit, Instituto de Investigación Sanitaria La Fe, Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain
| | - Marina Blazquez
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
| | - Carmen Ribes-Koninckx
- Coeliac Disease and Inmunopathology Research Unit, Instituto de Investigación Sanitaria La Fe, Pediatric Gastroenterology, Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain
| | - Jose V Castell
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain
- Biochemistry and Molecular Biology Department, Universidad de Valencia, Valencia, Spain
| | - Torsten Wuestefeld
- Laboratory for In Vivo Genetics & Gene Therapy, Genome Institute of Singapore, A*STAR & National Cancer Centre Singapore, School of Biological Science, SingHealth & Adj. Ass.-Prof. Nanyang Technological University, 60 Biopolis Street, #02-01 Genome, Singapore, 138672, Singapore
| | - Roque Bort
- Experimental Hepatology Unit, Instituto de Investigación Sanitaria La Fe, CIBERehd, Hospital Universitari i Politècnic La Fe, Avda. Fernando Abril Martorell 106, 46026, Valencia, Spain.
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Ballester M, Bolonio M, Santamaria R, Castell JV, Ribes-Koninckx C, Bort R. Direct conversion of human fibroblast to hepatocytes using a single inducible polycistronic vector. Stem Cell Res Ther 2019; 10:317. [PMID: 31685034 PMCID: PMC6829923 DOI: 10.1186/s13287-019-1416-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/30/2019] [Accepted: 09/12/2019] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Human fibroblasts can be reprogrammed into induced hepatocyte-like cells through the expression of a set of transcription factors. Although the generation of induced hepatocyte-like cells by HNF4A, HNF1A, and FOXA3 expression has proven to be a robust experimental strategy, using multiple lentivirus results in a highly variable heterogeneous population. METHODS We designed and implemented a novel approach based on the delivery of reprogramming factors and green fluorescent protein in a single doxycycline-inducible lentiviral vector using 2A self-cleaving peptides. RESULTS Fibroblasts infected with the lentiviral vector can be amplified in basic fibroblast culture media in the absence of doxycycline without induction of hepatic genes. Upon switching to hepatic maturation media containing doxycycline, cells stop proliferating, activate hepatic gene transcription, and perform metabolic functions characteristic of hepatocytes. CONCLUSION Our strategy can generate an unlimited source of homogeneously induced hepatocyte-like cells from different genetic background donors, capable of performing typical hepatic functions suitable for drug research and other in vitro applications.
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Affiliation(s)
- Maria Ballester
- Experimental Hepatology Research Unit, Instituto de Investigación Sanitaria La Fe, Hospital Universitari i Politècnic La Fe and CIBERehd, 46026, Valencia, Spain
| | - Miguel Bolonio
- Experimental Hepatology Research Unit, Instituto de Investigación Sanitaria La Fe, Hospital Universitari i Politècnic La Fe and CIBERehd, 46026, Valencia, Spain.,Coeliac Disease and Inmunopathology Research Unit, Instituto de Investigación Sanitaria La Fe. Pediatric Gastroenterology, Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain
| | - Ramon Santamaria
- Experimental Hepatology Research Unit, Instituto de Investigación Sanitaria La Fe, Hospital Universitari i Politècnic La Fe and CIBERehd, 46026, Valencia, Spain
| | - José V Castell
- Experimental Hepatology Research Unit, Instituto de Investigación Sanitaria La Fe, Hospital Universitari i Politècnic La Fe and CIBERehd, 46026, Valencia, Spain.,Biochemistry and Molecular Biology Department, Universidad de Valencia, Valencia, Spain
| | - Carmen Ribes-Koninckx
- Coeliac Disease and Inmunopathology Research Unit, Instituto de Investigación Sanitaria La Fe. Pediatric Gastroenterology, Hospital Universitari i Politècnic La Fe, 46026, Valencia, Spain
| | - Roque Bort
- Experimental Hepatology Research Unit, Instituto de Investigación Sanitaria La Fe, Hospital Universitari i Politècnic La Fe and CIBERehd, 46026, Valencia, Spain.
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Prieto J, León M, Ponsoda X, García-García F, Bort R, Serna E, Barneo-Muñoz M, Palau F, Dopazo J, López-García C, Torres J. Dysfunctional mitochondrial fission impairs cell reprogramming. Cell Cycle 2016; 15:3240-3250. [PMID: 27753531 DOI: 10.1080/15384101.2016.1241930] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We have recently shown that mitochondrial fission is induced early in reprogramming in a Drp1-dependent manner; however, the identity of the factors controlling Drp1 recruitment to mitochondria was unexplored. To investigate this, we used a panel of RNAi targeting factors involved in the regulation of mitochondrial dynamics and we observed that MiD51, Gdap1 and, to a lesser extent, Mff were found to play key roles in this process. Cells derived from Gdap1-null mice were used to further explore the role of this factor in cell reprogramming. Microarray data revealed a prominent down-regulation of cell cycle pathways in Gdap1-null cells early in reprogramming and cell cycle profiling uncovered a G2/M growth arrest in Gdap1-null cells undergoing reprogramming. High-Content analysis showed that this growth arrest was DNA damage-independent. We propose that lack of efficient mitochondrial fission impairs cell reprogramming by interfering with cell cycle progression in a DNA damage-independent manner.
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Affiliation(s)
- Javier Prieto
- a Department of Biología Celular , Biología Funcional y Antropología Física, Universitat de València , Burjassot , Spain
| | - Marian León
- a Department of Biología Celular , Biología Funcional y Antropología Física, Universitat de València , Burjassot , Spain
| | - Xavier Ponsoda
- a Department of Biología Celular , Biología Funcional y Antropología Física, Universitat de València , Burjassot , Spain
| | - Francisco García-García
- b Computational Genomics Department , Centro de Investigación Principe Felipe , Valencia , Spain.,c CIBER de Enfermedades Raras (CIBERER), ISCIII , Valencia , Spain
| | - Roque Bort
- d Unidad de Hepatología Experimental, CIBEREHD, IIS La Fe. , Valencia , Spain
| | - Eva Serna
- e Unidad Central de Investigación-INCLIVA, Universidad de Valencia , Valencia , Spain
| | - Manuela Barneo-Muñoz
- c CIBER de Enfermedades Raras (CIBERER), ISCIII , Valencia , Spain.,f Institut de Recerca Pediàtrica Hospital San Joan de Déu , Barcelona , Spain
| | - Francesc Palau
- c CIBER de Enfermedades Raras (CIBERER), ISCIII , Valencia , Spain.,f Institut de Recerca Pediàtrica Hospital San Joan de Déu , Barcelona , Spain
| | - Joaquín Dopazo
- b Computational Genomics Department , Centro de Investigación Principe Felipe , Valencia , Spain.,c CIBER de Enfermedades Raras (CIBERER), ISCIII , Valencia , Spain
| | - Carlos López-García
- a Department of Biología Celular , Biología Funcional y Antropología Física, Universitat de València , Burjassot , Spain
| | - Josema Torres
- a Department of Biología Celular , Biología Funcional y Antropología Física, Universitat de València , Burjassot , Spain
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Prieto J, León M, Ponsoda X, Sendra R, Bort R, Ferrer-Lorente R, Raya A, López-García C, Torres J. Early ERK1/2 activation promotes DRP1-dependent mitochondrial fission necessary for cell reprogramming. Nat Commun 2016; 7:11124. [PMID: 27030341 PMCID: PMC4821885 DOI: 10.1038/ncomms11124] [Citation(s) in RCA: 207] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 02/23/2016] [Indexed: 12/13/2022] Open
Abstract
During the process of reprogramming to induced pluripotent stem (iPS) cells, somatic cells switch from oxidative to glycolytic metabolism, a transition associated with profound mitochondrial reorganization. Neither the importance of mitochondrial remodelling for cell reprogramming, nor the molecular mechanisms controlling this process are well understood. Here, we show that an early wave of mitochondrial fragmentation occurs upon expression of reprogramming factors. Reprogramming-induced mitochondrial fission is associated with a minor decrease in mitochondrial mass but not with mitophagy. The pro-fission factor Drp1 is phosphorylated early in reprogramming, and its knockdown and inhibition impairs both mitochondrial fragmentation and generation of iPS cell colonies. Drp1 phosphorylation depends on Erk activation in early reprogramming, which occurs, at least in part, due to downregulation of the MAP kinase phosphatase Dusp6. Taken together, our data indicate that mitochondrial fission controlled by an Erk-Drp1 axis constitutes an early and necessary step in the reprogramming process to pluripotency.
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Affiliation(s)
- Javier Prieto
- Departamento de Biología Celular, Universidad de Valencia, Burjassot 46100, Spain
| | - Marian León
- Departamento de Biología Celular, Universidad de Valencia, Burjassot 46100, Spain
| | - Xavier Ponsoda
- Departamento de Biología Celular, Universidad de Valencia, Burjassot 46100, Spain
| | - Ramón Sendra
- Departamento de Bioquímica y Biología Molecular, Universidad de Valencia, Burjassot 46100, Spain
| | - Roque Bort
- Unidad de Hepatología Experimental, CIBERehd, Instituto de Investigación Sanitaria La Fe, Valencia 46026, Spain
| | - Raquel Ferrer-Lorente
- Centre de Medicina Regenerativa de Barcelona, Barcelona 08003, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina, Madrid 28029, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona 08010, Spain
| | - Angel Raya
- Centre de Medicina Regenerativa de Barcelona, Barcelona 08003, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina, Madrid 28029, Spain
- Institució Catalana de Recerca i Estudis Avançats, Barcelona 08010, Spain
| | - Carlos López-García
- Departamento de Biología Celular, Universidad de Valencia, Burjassot 46100, Spain
| | - Josema Torres
- Departamento de Biología Celular, Universidad de Valencia, Burjassot 46100, Spain
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Abstract
Primary cultured hepatocytes are probably the best model to study endogenous metabolic pathways, toxicity, or drug metabolism. Many of these studies require expression of ectopic genes. It would be desirable to use a method of transfection that allows dose-response studies, high efficiency of transfection, and the possibility to express several genes at the same time. Adenoviral vectors fulfill these requirements, becoming a valuable tool for primary hepatocyte transfection. Moreover, they are easy to generate and do not require a high level of biocontainment. In the present chapter, we describe the generation, cloning, amplification, and purification of an adenoviral vector capable of infecting primary cultured hepatocytes. This recombinant adenovirus induces robust expression of the protein of interest in hepatocytes within a wide range of doses.
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Affiliation(s)
- Marta Benet
- Unidad de Hepatología Experimental-CIBERehd, Instituto de Investigación Sanitaria La Fe, Valencia, Spain
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Gieseck III RL, Hannan NRF, Bort R, Hanley NA, Drake RAL, Cameron GWW, Wynn TA, Vallier L. Maturation of induced pluripotent stem cell derived hepatocytes by 3D-culture. PLoS One 2014; 9:e86372. [PMID: 24466060 PMCID: PMC3899231 DOI: 10.1371/journal.pone.0086372] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 12/06/2013] [Indexed: 01/28/2023] Open
Abstract
Induced pluripotent stem cell derived hepatocytes (IPSC-Heps) have the potential to reduce the demand for a dwindling number of primary cells used in applications ranging from therapeutic cell infusions to in vitro toxicology studies. However, current differentiation protocols and culture methods produce cells with reduced functionality and fetal-like properties compared to adult hepatocytes. We report a culture method for the maturation of IPSC-Heps using 3-Dimensional (3D) collagen matrices compatible with high throughput screening. This culture method significantly increases functional maturation of IPSC-Heps towards an adult phenotype when compared to conventional 2D systems. Additionally, this approach spontaneously results in the presence of polarized structures necessary for drug metabolism and improves functional longevity to over 75 days. Overall, this research reveals a method to shift the phenotype of existing IPSC-Heps towards primary adult hepatocytes allowing such cells to be a more relevant replacement for the current primary standard.
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Affiliation(s)
- Richard L. Gieseck III
- Wellcome Trust–Medical Research Council Stem Cell Institute, Anne McLaren Laboratory for Regenerative Medicine, Department of Surgery, University of Cambridge, Cambridge, United Kingdom
- Immunopathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nicholas R. F. Hannan
- Wellcome Trust–Medical Research Council Stem Cell Institute, Anne McLaren Laboratory for Regenerative Medicine, Department of Surgery, University of Cambridge, Cambridge, United Kingdom
| | - Roque Bort
- Unidad de Hepatología Experimental, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas, Instituto de Investigación Sanitaria La Fe, Valencia, Spain
| | - Neil A. Hanley
- Centre for Endocrinology and Diabetes, Institute of Human Development, Faculty of Medical & Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, United Kingdom
| | | | | | - Thomas A. Wynn
- Immunopathogenesis Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ludovic Vallier
- Wellcome Trust–Medical Research Council Stem Cell Institute, Anne McLaren Laboratory for Regenerative Medicine, Department of Surgery, University of Cambridge, Cambridge, United Kingdom
- Wellcome Trust Sanger Institute, Hinxton, United Kingdom
- * E-mail:
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Blazquez M, Carretero A, Ellis JK, Athersuch TJ, Cavill R, Ebbels TMD, Keun HC, Castell JV, Lahoz A, Bort R. A combination of transcriptomics and metabolomics uncovers enhanced bile acid biosynthesis in HepG2 cells expressing CCAAT/enhancer-binding protein β (C/EBPβ), hepatocyte nuclear factor 4α (HNF4α), and constitutive androstane receptor (CAR). J Proteome Res 2013; 12:2732-41. [PMID: 23641669 DOI: 10.1021/pr400085n] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The development of hepatoma-based in vitro models to study hepatocyte physiology is an invaluable tool for both industry and academia. Here, we develop an in vitro model based on the HepG2 cell line that produces chenodeoxycholic acid, the main bile acid in humans, in amounts comparable to human hepatocytes. A combination of adenoviral transfections for CCAAT/enhancer-binding protein β (C/EBPβ), hepatocyte nuclear factor 4α (HNF4α), and constitutive androstane receptor (CAR) decreased intracellular glutamate, succinate, leucine, and valine levels in HepG2 cells, suggestive of a switch to catabolism to increase lipogenic acetyl CoA and increased anaplerosis to replenish the tricarboxylic acid cycle. Transcripts of key genes involved in bile acid synthesis were significantly induced by approximately 160-fold. Consistently, chenodeoxycholic acid production rate was increased by more than 20-fold. Comparison between mRNA and bile acid levels suggest that 12-alpha hydroxylation of 7-alpha-hydroxy-4-cholesten-3-one is the limiting step in cholic acid synthesis in HepG2 cells. These data reveal that introduction of three hepatocyte-related transcription factors enhance anabolic reactions in HepG2 cells and provide a suitable model to study bile acid biosynthesis under pathophysiological conditions.
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Affiliation(s)
- Marina Blazquez
- Unidad de Hepatología Experimental, CIBERehd, Instituto de Investigación Sanitaria La Fe, Valencia 46009, Spain
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Doktorova TY, Yildirimman R, Vinken M, Vilardell M, Vanhaecke T, Gmuender H, Bort R, Brolen G, Holmgren G, Li R, Chesne C, van Delft J, Kleinjans J, Castell J, Bjorquist P, Herwig R, Rogiers V. Transcriptomic responses generated by hepatocarcinogens in a battery of liver-based in vitro models. Carcinogenesis 2013; 34:1393-402. [PMID: 23393228 DOI: 10.1093/carcin/bgt054] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
As the conventional approach to assess the potential of a chemical to cause cancer in humans still includes the 2-year rodent carcinogenicity bioassay, development of alternative methodologies is needed. In the present study, the transcriptomics responses following exposure to genotoxic (GTX) and non-genotoxic (NGTX) hepatocarcinogens and non-carcinogens (NC) in five liver-based in vitro models, namely conventional and epigenetically stabilized cultures of primary rat hepatocytes, the human hepatoma-derived cell lines HepaRG and HepG2 and human embryonic stem cell-derived hepatocyte-like cells, are examined. For full characterization of the systems, several bioinformatics approaches are employed including gene-based, ConsensusPathDB-based and classification analysis. They provide convincingly similar outcomes, namely that upon exposure to carcinogens, the HepaRG generates a gene classifier (a gene classifier is defined as a selected set of characteristic gene signatures capable of distinguishing GTX, NGTX carcinogens and NC) able to discriminate the GTX carcinogens from the NGTX carcinogens and NC. The other in vitro models also yield cancer-relevant characteristic gene groups for the GTX exposure, but some genes are also deregulated by the NGTX carcinogens and NC. Irrespective of the tested in vitro model, the most uniformly expressed pathways following GTX exposure are the p53 and those that are subsequently induced. The NGTX carcinogens triggered no characteristic cancer-relevant gene profiles in all liver-based in vitro systems. In conclusion, liver-based in vitro models coupled with transcriptomics techniques, especially in the case when the HepaRG cell line is used, represent valuable tools for obtaining insight into the mechanism of action and identification of GTX carcinogens.
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Affiliation(s)
- Tatyana Y Doktorova
- Department of Toxicology, Center for Pharmaceutical Research, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
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11
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Serrano F, Calatayud CF, Blazquez M, Torres J, Castell JV, Bort R. Gata4 Blocks Somatic Cell Reprogramming By Directly Repressing Nanog. Stem Cells 2012; 31:71-82. [DOI: 10.1002/stem.1272] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 10/04/2012] [Indexed: 12/31/2022]
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12
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Marfil V, Moya M, Pierreux CE, Castell JV, Lemaigre FP, Real FX, Bort R. Interaction between Hhex and SOX13 modulates Wnt/TCF activity. J Biol Chem 2009; 285:5726-37. [PMID: 20028982 DOI: 10.1074/jbc.m109.046649] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fine-tuning of the Wnt/TCF pathway is crucial for multiple embryological processes, including liver development. Here we describe how the interaction between Hhex (hematopoietically expressed homeobox) and SOX13 (SRY-related high mobility group box transcription factor 13), modulates Wnt/TCF pathway activity. Hhex is a homeodomain factor expressed in multiple endoderm-derived tissues, like the liver, where it is essential for proper development. The pleiotropic expression of Hhex during embryonic development and its dual role as a transcriptional repressor and activator suggest the presence of different tissue-specific partners capable of modulating its activity and function. While searching for developmentally regulated Hhex partners, we set up a yeast two-hybrid screening using an E9.5-10.5 mouse embryo library and the N-terminal domain of Hhex as bait. Among the putative protein interactors, we selected SOX13 for further characterization. We found that SOX13 interacts directly with full-length Hhex, and we delineated the interaction domains within the two proteins. SOX13 is known to repress Wnt/TCF signaling by interacting with TCF1. We show that Hhex is able to block the SOX13-dependent repression of Wnt/TCF activity by displacing SOX13 from the SOX13 x TCF1 complex. Moreover, Hhex de-repressed the Wnt/TCF pathway in the ventral foregut endoderm of cultured mouse embryos electroporated with a SOX13-expressing plasmid. We conclude that the interaction between Hhex and SOX13 may contribute to control Wnt/TCF signaling in the early embryo.
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Affiliation(s)
- Vanessa Marfil
- Unitat de Biologia Cellular i Molecular, Institut Municipal d'Investigació Mèdica, Universitat Pompeu Fabra, Barcelona 08003, Spain
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13
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Bort R, Signore M, Tremblay K, Martinez Barbera JP, Zaret KS. Hex homeobox gene controls the transition of the endoderm to a pseudostratified, cell emergent epithelium for liver bud development. Dev Biol 2006; 290:44-56. [PMID: 16364283 DOI: 10.1016/j.ydbio.2005.11.006] [Citation(s) in RCA: 189] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 10/26/2005] [Accepted: 11/04/2005] [Indexed: 11/18/2022]
Abstract
Little is known about the mechanism by which embryonic liver, lung, and pancreas progenitor cells emerge from the endodermal epithelium to initiate organogenesis. Understanding this process and its genetic control provides insight into ontogeny, developmental abnormalities, and tissue regeneration. We find that shortly after hepatic endoderm cells are specified, they undergo a transition from a columnar, gut morphology to a pseudostratified morphology, with concomitant "interkinetic nuclear migration" (INM) during cell division. INM is a hallmark of pseudostratified epithelia and the process used by neural progenitors to emerge from the neural epithelium. We find that the transition of the hepatic endoderm, but not the neural epithelium, to a pseudostratified epithelium is dependent upon the cell-autonomous activity of the homeobox gene Hex. In the absence of Hex, hepatic endoderm cells survive but maintain a columnar, simple epithelial phenotype and ectopically express Shh and other genes characteristic of the midgut epithelium. Thus, Hex promotes endoderm organogenesis by promoting the transition to a pseudostratified epithelium, which in turn allows hepatoblasts to emerge into the stromal environment and continue differentiating.
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Affiliation(s)
- Roque Bort
- Cell and Developmental Biology Program, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA
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14
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Chang J, Nicolas E, Marks D, Sander C, Lerro A, Buendia MA, Xu C, Mason WS, Moloshok T, Bort R, Zaret KS, Taylor JM. miR-122, a mammalian liver-specific microRNA, is processed from hcr mRNA and may downregulate the high affinity cationic amino acid transporter CAT-1. RNA Biol 2004; 1:106-13. [PMID: 17179747 DOI: 10.4161/rna.1.2.1066] [Citation(s) in RCA: 632] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
These studies show that miR-122, a 22-nucleotide microRNA, is derived from a liver-specific noncoding polyadenylated RNA transcribed from the gene hcr. The exact sequence of miR-122 as well as the adjacent secondary structure within the hcr mRNA are conserved from mammalian species back to fish. Levels of miR-122 in the mouse liver increase to half maximal values around day 17 of embryogenesis, and reach near maximal levels of 50,000 copies per average cell before birth. Lewis et al. (2003) predicted the cationic amino acid transporter (CAT-1 or SLC7A1) as a miR-122 target. CAT-1 protein and its mRNA are expressed in all mammalian tissues but with lower levels in adult liver. Furthermore, during mouse liver development CAT-1 mRNA decreases in an almost inverse correlation with miR-122. Eight potential miR-122 target sites were predicted within the human CAT-1 mRNA, with six in the 3'-untranslated region. Using a reporter construct it was found that just three of the predicted sites, linked in a 400-nucleotide sequence from human CAT-1, acted with synergy and were sufficient to strongly inhibit protein synthesis and reduce mRNA levels. In summary, these studies followed the accumulation during development of miR-122 from its mRNA precursor, hcr, through to identification of what may be a specific mRNA target, CAT-1.
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Affiliation(s)
- Jinhong Chang
- Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111-2497, USA
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15
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Bort R, Gómez-Lechón MJ, Castell JV, Jover R. Role of hepatocyte nuclear factor 3γ in the expression of human CYP2C genes. Arch Biochem Biophys 2004; 426:63-72. [PMID: 15130783 DOI: 10.1016/j.abb.2004.03.032] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Revised: 03/24/2004] [Indexed: 11/17/2022]
Abstract
Hepatocyte nuclear factor 3 gamma (HNF-3 gamma) is an important transcription factor for the maintenance of specific liver functions. However, its relevance in the expression of human cytochrome P450 (CYP) genes has not yet been explored. Several HNF3 putative binding sites can be identified in human CYP2C 5'-flanking regions. Gene reporter experiments with proximal promoters revealed that HNF-3 gamma transactivated CYP2C8, CYP2C9, and CYP2C19 (25-, 4-, and 4-fold, respectively), but it did not transactivate CYP2C18. However, overexpression of HNF-3 gamma in hepatoma cells by means of a recombinant adenovirus induced CYP2C9, CYP2C18, and CYP2C19 mRNA (4.5-, 20-, and 50-fold, respectively) but did not activate endogenous CYP2C8. The lack of effect of HNF-3 gamma on endogenous CYP2C8 could be reversed by treating cells with the deacetylase inhibitor, trichostatin A, suggesting the existence of chromatin condensation around functional HNF3 elements in this gene. We conclude that HNF3 gamma is an important transcription factor for the hepatic-specific expression of human CYP2C genes. Our results also evidence that efficient transfection tools, such as adenoviral vectors, may be decisive for assessing the role of transcription factor on chromatin organized genes.
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Affiliation(s)
- Roque Bort
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital Universitario La Fe. Avda. Campanar 21, E-46009, Valencia, Spain
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16
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Bort R, Martinez-Barbera JP, Beddington RSP, Zaret KS. Hex homeobox gene-dependent tissue positioning is required for organogenesis of the ventral pancreas. Development 2004; 131:797-806. [PMID: 14736744 DOI: 10.1242/dev.00965] [Citation(s) in RCA: 209] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In animal development, digestive tissues emerge from different positions of the endoderm as a result of patterning signals from overlying mesoderm. Although embryonic tissue movement during gastrulation generates an initial positional relationship between the endoderm and mesoderm, the role of subsequent endoderm movement against the mesoderm in patterning is unknown. At embryonic day 8.5 in the mouse, proliferation of cells at the leading edge of ventral-lateral endoderm, where the liver and ventral pancreas emerge, helps close off the foregut. During this time, the endoderm grows adjacent to and beyond the cardiogenic mesoderm, an inducer of the liver program and an inhibitor of the pancreas program. The homeobox gene Hex is expressed in this endoderm cell domain and in the liver and ventral pancreas buds, after organogenesis. We have found that in Hex(-/-) embryos, there is a complete failure in ventral pancreatic specification, while the liver program is still induced. However, when Hex-null ventral endoderm is isolated prior to its interaction with cardiogenic mesoderm and is cultured in vitro, it activates early pancreas genes. We found that Hex controls the proliferation rate, and thus the positioning, of the leading edge of endoderm cells that grow beyond the cardiogenic mesoderm, during gut tube closure. Thus, Hex-controlled positioning of endoderm cells beyond cardiogenic mesoderm dictates ventral pancreas specification. Other endodermal transcription factors may also function morphogenetically rather than by directly regulating tissue-specific programs.
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Affiliation(s)
- Roque Bort
- Cell and Developmental Biology Program, Fox Chase Cancer Center, 7701 Burholme Aveue, Philadelphia, PA 19111, USA
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17
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Rodríguez-Antona C, Bort R, Jover R, Tindberg N, Ingelman-Sundberg M, Gómez-Lechón MJ, Castell JV. Transcriptional regulation of human CYP3A4 basal expression by CCAAT enhancer-binding protein alpha and hepatocyte nuclear factor-3 gamma. Mol Pharmacol 2003; 63:1180-9. [PMID: 12695546 DOI: 10.1124/mol.63.5.1180] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cytochrome P450 3A4 (CYP3A4) is involved in the metabolism of more than 50% of currently used therapeutic drugs, yet the mechanisms that control CYP3A4 basal expression in liver are poorly understood. Several putative binding sites for CCAAT/enhancer-binding protein (C/EBP) and hepatic nuclear factor 3 (HNF-3) were found by computer analysis in CYP3A4 promoter. The use of reporter gene assays, electrophoretic mobility shift assays, and site-directed mutagenesis revealed that one proximal and two distal C/EBP alpha binding sites are essential sites for the trans-activation of CYP3A4 promoter. No trans-activation was found in similar reporter gene experiments with a HNF-3 gamma expression vector. The relevance of these findings was further explored in the more complex DNA/chromatin structure within endogenous CYP3A4 gene. Using appropriate adenoviral expression vectors, we found that both hepatic and nonhepatic cells overexpressing C/EBP alpha had increased CYP3A4 mRNA levels, but no effect was observed when HNF-3 gamma was overexpressed. In contrast, overexpression of HNF-3 gamma simultaneously with C/EBP alpha resulted in a greater activation of the CYP3A4 gene. This cooperative effect was hepatic-specific and also occurred in CYP3A5 and CYP3A7 genes. To investigate the mechanism for HNF-3 gamma action, we studied its binding to CYP3A4 promoter and the effect of the deacetylase inhibitor trichostatin A. HNF-3 gamma was able to bind CYP3A4 promoter at a distal position, near the most distal C/EBP alpha binding site. Trichostatin A increased C/EBP alpha effect but abolished HNF-3 gamma cooperative action. These findings revealed that C/EBP alpha and HNF-3 gamma cooperatively regulate CYP3A4 expression in hepatic cells by a mechanism that probably involves chromatin remodeling.
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Affiliation(s)
- C Rodríguez-Antona
- Departamento de Bioquímica, Facultad de Medicina, Universidad de Valencia, Valencia, Spain
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18
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Jover R, Bort R, Gómez-Lechón MJ, Castell JV. Down-regulation of human CYP3A4 by the inflammatory signal interleukin-6: molecular mechanism and transcription factors involved. FASEB J 2002; 16:1799-801. [PMID: 12354697 DOI: 10.1096/fj.02-0195fje] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The hepatic drug-metabolizing cytochrome P-450 (CYP) enzymes are down-regulated during inflammation. In vitro studies with hepatocytes have shown that the cytokines released during inflammatory responses are largely responsible for this CYP repression. However, the signaling pathways and the cytokine-activated factors involved remain to be properly identified. Our research has focused on the negative regulation of CYP3A4 (the major drug-metabolizing human CYP) by interleukin 6 (IL-6) (the principal regulator of the hepatic acute-phase response). CYP3A4 down-regulation by IL-6 requires activation of the glycoprotein receptor gp130; however, it does not proceed through the JAK/STAT pathway, as demonstrated by the overexpression of a dominant-negative STAT3 factor by means of an adenoviral vector. The involvement of IL-6-activated kinases such as extracellular signal-regulated kinase ERK1/2 or p38 is also unlikely, as evidenced by the use of specific chemical inhibitors. It is noteworthy that IL-6 caused a moderated induction in the mRNA of the transcription factor C/EBPbeta (CCAAT-enhancer binding protein beta) and a marked increase in the translation of C/EBPbeta-LIP, a 20-kDa C/EBPbeta isoform lacking a transactivation domain. Adenovirus-mediated expression of C/EBPbeta-LIP caused a dose-dependent repression of CYP3A4 mRNA, whereas overexpression C/EBPalpha and C/EBPb-LAP (35 kDa) caused a significant induction. Our results support the idea that IL-6 down-regulates CYP3A4 through translational induction of C/EBPbeta-LIP, which competes with and antagonizes constitutive C/EBP transactivators. From a clinical point of view, these findings could be relevant in the development of therapeutic cytokines with a less repressive effect on hepatic drug-metabolizing enzymes.
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Affiliation(s)
- Ramiro Jover
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital Universitario La Fe, E-46009 Valencia, Spain
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19
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20
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Gómez-Lechón MJ, Ponsoda X, Bort R, Castell JV. The use of cultured hepatocytes to investigate the metabolism of drugs and mechanisms of drug hepatotoxicity. Altern Lab Anim 2001; 29:225-31. [PMID: 11387019 DOI: 10.1177/026119290102900307] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hepatotoxins can be classified as intrinsic when they exert their effects on all individuals in a dose-dependent manner, and as idiosyncratic when their effects are the consequence of an abnormal metabolism of the drug by susceptible individuals (metabolic idiosyncrasy) or of an immune-mediated injury to hepatocytes (allergic hepatitis). Some xenobiotics are electrophilic, and others are biotransformed by the liver into highly reactive metabolites that are usually more toxic than the parent compound. This activation process is the key to many hepatotoxic phenomena. Mitochondria are a frequent target of hepatotoxic drugs, and the alteration of their function has immediate effects on the energy balance of cells (depletion of ATP). Lipid peroxidation, oxidative stress, alteration of Ca(2+) homeostasis, and covalent binding to cell macromolecules are the molecular mechanisms that are frequently involved in the toxicity of xenobiotics. Against these potential hazards, cells have their own defence mechanisms (for example, glutathione, DNA repair, suicide inactivation). Ultimately, toxicity is the balance between bioactivation and detoxification, which determines whether a reactive metabolite elicits a toxic effect. The ultimate goal of in vitro experiments is to generate the type of scientific information needed to identify compounds that are potentially toxic to man. For this purpose, both the design of the experiments and the interpretation of the results are critical.]
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Affiliation(s)
- M J Gómez-Lechón
- Unidad de Hepatologia Experimental, Centro de Investigación, Hospital Universitario La Fe, Avenida de Campanar 21, 46009 Valencia, Spain
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Jover R, Bort R, Gómez-Lechón MJ, Castell JV. Cytochrome P450 regulation by hepatocyte nuclear factor 4 in human hepatocytes: a study using adenovirus-mediated antisense targeting. Hepatology 2001; 33:668-75. [PMID: 11230748 DOI: 10.1053/jhep.2001.22176] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Hepatocyte nuclear factor 4 (HNF4) is a member of the nuclear receptor super-family that has shown activating effects on particular cytochrome P450 (CYP) promoters from several species. However, its role in the regulation of human CYPs in the liver is still poorly understood, as no comprehensive studies in human-relevant models have been performed. In the present study, we have investigated whether HNF4 plays a general role in the expression of 7 major CYP genes in primary cultured human hepatocytes. To this end, we developed an adenoviral vector for efficient expression of HNF4 antisense RNA. Transduction of human hepatocytes with the recombinant adenovirus resulted in a time-dependent increase in the antisense transcript, followed by a concomitant decrease in apolipoprotein C III mRNA (a target gene of HNF4). Specificity was confirmed by showing that increasing levels of HNF4 antisense RNA resulted in the reduction of HNF4 protein, whereas retinoic X receptoralpha-(RXRalpha), the closest homologous member of the nuclear receptor super-family, was unaffected. Analysis of CYP gene expression in human hepatocytes transfected with HNF4 antisense RNA revealed singular behaviors: (1) CYP3A4, CYP3A5, and CYP2A6 showed an important, dose-dependent down-regulation on blockage of HNF4 translation; (2) a moderate inhibition of CYP2B6, CYP2C9, and CYP2D6 expression was observed (40%-45% reduction); (3) the levels of CYP2E1 were not affected even in the absence of this transcription factor. In conclusion, using an original strategy (efficient antisense RNA expression vector), our study shows that HNF4 is a general regulator supporting the expression of major drug-metabolizing CYPs in human hepatocytes.
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Affiliation(s)
- R Jover
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital Universitario La Fe, SVS, Valencia, Spain
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Cortijo J, Urbieta E, Bort R, Castell JV, Ruiz-Bravo C, Martinez J, Palacios-Pelaez R, Lledó S, Morcillo EJ. Biotransformation in vitro of the 22R and 22S epimers of budesonide by human liver, bronchus, colonic mucosa and skin. Fundam Clin Pharmacol 2001; 15:47-54. [PMID: 11468013 DOI: 10.1046/j.1472-8206.2001.00005.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The pharmacological effects of glucocorticoids are greatly influenced by their pharmacokinetic properties. In the present report, the in vitro biotransformation of the 22R and 22S epimers of the topical steroid budesonide was studied in the S-9 fraction of human liver, bronchus, skin and colonic mucosa. The disappearance of unchanged epimers of budesonide was measured during 90 min of incubation by high performance liquid chromatography. The rate of disappearance was high in human liver while little biotransformation occurred in bronchial tissue and colonic mucosa, and none was detected in the skin. A marked decay of the initial concentration of unchanged budesonide epimers was noticed after 2 h incubation in cultured human hepatocytes, while only a small decrease was observed after 24 h incubation in cultured human airway smooth muscle cells and BEAS-2B cells. The 22R epimer of budesonide suffered greater in vitro biotransformation than the 22S epimer in human hepatic, bronchial and colonic tissues. These findings extend those of other studies, and confirm that the high therapeutic ratio of budesonide is due to negligible local biotransformation combined with high level of liver metabolism for locally absorbed budesonide.
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Affiliation(s)
- J Cortijo
- Department of Pharmacology, University of Valencia, Valencia, Spain.
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Siewert E, Bort R, Kluge R, Heinrich PC, Castell J, Jover R. Hepatic cytochrome P450 down-regulation during aseptic inflammation in the mouse is interleukin 6 dependent. Hepatology 2000; 32:49-55. [PMID: 10869288 DOI: 10.1053/jhep.2000.8532] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/07/2022]
Abstract
Expression of cytochromes P450 (CYP) is markedly reduced during inflammatory processes. In vitro studies with hepatocytes have shown that cytokines generated during these processes down-regulate CYP. However, it is not clear to what extent each individual cytokine contributes to the overall reduced expression of the various CYP isoenzymes in vivo. Interleukin 6 (IL-6), a major player during inflammatory processes, is recognized as the most important cytokine modulating the hepatic expression of acute-phase protein (APP) genes. For this reason, we selected the IL-6(-/-) mouse as a model to investigate the role of IL-6 in the down-regulation of hepatic CYP during experimental inflammation. Our results show that the reduction in messenger RNA (mRNA) levels of CYP1A2, CYP2A5, and CYP3A11 during turpentine-induced inflammation was abrogated in IL-6-deficient mice, confirming that IL-6 is an indispensable player for the down-regulation of hepatic CYP during aseptic inflammation. Moreover, the different CYP isoenzymes showed a variable grade of dependence on IL-6, CYP2A5 being the most sensitive one. In the case of CYP2E1, differences between IL-6(-/-) and wild-type mice were no longer maintained after 24 hours, suggesting a delayed, rather than abrogated, CYP down-regulation in the absence of IL-6. As opposed to that, hepatic CYP repression took place in IL-6-deficient mice during lipopolysaccharide (LPS)-mediated inflammation. This contrasting behavior observed for CYP is surprisingly similar to the one seen for extracellular (serum amyloid A, beta-fibrinogen) and intracellular (metallothionein-1) APPs and points to the fact that, in the model of bacterial inflammation (LPS), the effects of IL-6 on CYP down-regulation are likely to be substituted by other cytokines or mediators.
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Affiliation(s)
- E Siewert
- Institut f]ur Biochemie der RWTH Aachen, Aachen, Germany
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Abstract
Increased toxicity of cocaine to human hepatocytes is observed when cells are simultaneously incubated with ethanol. Ethanol might exacerbate cocaine hepatocyte toxicity by three different pathways: a) by increasing the oxidative metabolism of cocaine and hence the oxidative damage; b) by the formation of a more toxic metabolite, namely cocaethylene; or c) by decreasing the defence mechanisms of the cell (i.e. GSH). In the present study, experiments were conducted to investigate the feasibility of these hypotheses. In hepatocytes preincubated for 48 hr with ethanol, neither significant changes in cocaine metabolism nor cytotoxicity were found despite differences in hepatocyte p-nitrophenol hydroxylase (largely CYP2E1 activity). Cocaethylene, the transesterification product of cocaine and ethanol, was found to be more toxic than cocaine for human hepatocytes (3x). However, the small amount formed when human hepatocytes were incubated with cocaine and ethanol would hardly explain the increased toxicity observed. On the other hand, the simultaneous presence of cocaine and ethanol caused a sustained decline in the intracellular GSH content that was larger than that observed in cocaine- or ethanol-treated cultures. Parallel to this phenomenon, a significant increase in lipid peroxidation was observed, as compared to cells treated with equimolar amounts of cocaine, ethanol, or cocaethylene. Finally, depletion of hepatocyte GSH with diethylmaleate down to levels similar to those found in ethanol-treated cells made hepatocytes more susceptible to cocaine. Taken together, the results of this research suggest that by decreasing GSH levels, ethanol makes human hepatocytes more sensitive to cocaine-induced oxidative damage.
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Affiliation(s)
- X Ponsoda
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital La Fe, Valencia, Spain
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Bort R, Macé K, Boobis A, Gómez-Lechón MJ, Pfeifer A, Castell J. Hepatic metabolism of diclofenac: role of human CYP in the minor oxidative pathways. Biochem Pharmacol 1999; 58:787-96. [PMID: 10449188 DOI: 10.1016/s0006-2952(99)00167-7] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
The aim of this study was to re-examine the human hepatic metabolism of diclofenac, with special focus on the generation of minor hydroxylated metabolites implicated in the idiosyncratic hepatotoxicity of the drug. Different experimental approaches were used: human hepatocytes, human microsomes, and engineered cells expressing single human CYP (cytochromes P450). Human hepatocytes formed 3'-hydroxy-, 4'-hydroxy-, 5-hydroxy- 4',5-dihydroxy-, and N,5-dihydroxydiclofenac, as well as several lactams. Formation of 4'- and 5-hydroxydiclofenac by human liver microsomes followed a Michaelis-Menten kinetics (Km 9 +/- 1 microM; Vmax 432 +/- 15 pmol/min/mg and Km 43 +/- 5 microM; and Vmax 15.4 +/- 0.6 pmol/min/mg, respectively). Secondary metabolites were detected after incubation of 5-hydroxydiclofenac with human liver microsomes, yielding 4',5-dihydroxydiclofenac (Km 15 +/- 1 microM; Vmax 96 +/- 3 pmol/min/mg) and small amounts of N,5-dihydroxydiclofenac (non-Michaelis-Menten kinetics). Based on microsome studies and the incubations with human hepatocytes and engineered cells, we estimated that in vivo CYP2C9 would be exclusively responsible for the 4' hydroxylation of diclofenac (>99.5%) as well as 5-hydroxydiclofenac (>97%). CYP2C9 was exclusively responsible for the formation of 3'-hydroxydiclofenac. Multiple regression analysis evidenced that the rate of production of 5-hydroxydiclofenac in human microsomes followed the algorithm: 0.040 x S-mephenytoin 4'-hydroxylation + 0.083 x tolbutamide methylhydroxylation, (multiple correlation coefficient = 0.969). However, the incubation of diclofenac with cell lines expressing different human CYP suggested that 7 isoforms could be involved. Comparison of data obtained with CYP-expressing cells and human hepatocytes suggests that CYP2C8 > CYP2C19 approximately CYP2C18 >> CYP2B6 are the isoforms implicated in the 5-hydroxylation of diclofenac in vivo.
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Affiliation(s)
- R Bort
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital Universitario La Fe, Valencia, Spain
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Bort R, Ponsoda X, Jover R, Gómez-Lechón MJ, Castell JV. Diclofenac toxicity to hepatocytes: a role for drug metabolism in cell toxicity. J Pharmacol Exp Ther 1999; 288:65-72. [PMID: 9862754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Diclofenac, a 2-arylacetic acid, nonsteroidal anti-inflammatory drug, has been reported to cause adverse hepatic effects in certain individuals. To discriminate among possible mechanisms of hepatotoxicity, we examined the effects of diclofenac on human and rat hepatocytes and hepatic cell lines (HepG2, FaO), investigated the major biochemical events in the course of diclofenac cytotoxicity (calcium homeostasis, lipid peroxidation, and mitochondrial dysfunction), and investigated whether cytotoxicity could be related to drug metabolism by cytochrome P-450. Acute diclofenac-induced toxicity in hepatocytes was preluded by a decrease in ATP levels, whereas no significant oxidative stress (decrease in glutathione and lipid peroxidation) or increase in intracellular calcium concentration could be observed at early incubation stages. Diclofenac was more cytotoxic to drug metabolizing cells (rat and human primary cultured hepatocytes) than to nonmetabolizing cell lines (HepG2, FaO). Despite the fact that diclofenac itself was effective in impairing ATP synthesis by mitochondria, we found evidence that toxicity was also related to drug metabolism and was reduced by the addition of cytochrome P-450 inhibitors (proadifen and ketoconazole) to culture medium. The in vitro cytotoxicity correlated well with the formation by hepatocytes of 5-hydroxydiclofenac and, in particular, N,5-dihydroxydiclofenac, a minor metabolite first characterized in this article. Hepatic microsomes showed the ability to both oxidize 5-hydroxydiclofenac to N,5-dihydroxydiclofenac and back reduce the latter to 5-hydroxydiclofenac with the consumption of NADPH. The experimental results suggest that the toxic effect of diclofenac on hepatocytes may be caused by drug-induced mitochondrial impairment, together with a futile consumption of NADPH.
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Affiliation(s)
- R Bort
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital Universitario "La Fe", Valencia, Spain
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Gómez-Lechón MJ, Jover R, Donato T, Ponsoda X, Rodriguez C, Stenzel KG, Klocke R, Paul D, Guillén I, Bort R, Castell JV. Long-term expression of differentiated functions in hepatocytes cultured in three-dimensional collagen matrix. J Cell Physiol 1998; 177:553-62. [PMID: 10092208 DOI: 10.1002/(sici)1097-4652(199812)177:4<553::aid-jcp6>3.0.co;2-f] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Hepatocytes entrapped in collagen gel and cultured in serum-free conditions survived longer than cells cultured on plastic (5 days vs. 3 weeks), showed fewer signs of early cell senescence (no increase in c-fos oncoprotein expression), and maintained the expression of differentiated hepatic metabolic functions over a longer period of time. Cells cultured in collagen gels retained their ability to respond to hormones. The insulin-stimulated glycogen synthesis rate remained fairly constant during 18 days in culture (between 5.4 +/- 0.37 and 9 +/- 2.7 nmol glucose/h/microg DNA). Collagen-cultured hepatocytes recovered glycogen stores to levels similar to those found in liver, or in hepatocytes isolated from fed rats. Urea synthesis from ammonia remained stable for more than 2 weeks (average value, 23 +/- 4 nmol urea/h/microg DNA). The rate of albumin synthesis in collagen-entrapped cells was maintained above the day-1 level during 18 days in culture. Cells showed high levels of glutathione (GSH) (1,278 +/- 152 pmol/microg DNA). Biotransformation activities CYP4501A1, CYP4502A2, CYP4502B1, and CYP4503A1 remained fairly stable in collagen-cultured hepatocytes. CYP4502E1 and CYP4502C11 decreased but were still measurable after 18 days. After 4 days in culture, GST activity returned to levels observed in isolated hepatocytes. In contrast with plastic cultures, cells responded to CYP450 inducers (methylcholanthrene for CYP4501A1, CYP4501A2, and glutathione-transferase, and ethanol for CYP4502E1) for more than 2 weeks. CYP4501A1, CYP4501A2, and glutathione-transferase A2 (GST A2) induction was preceded by an increase in specific mRNA, while the effects on CYP4502E1 seemed to be at a posttranslational level. Analysis of the expression of relevant hepatic genes by reverse Northern and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) revealed that culturing hepatocytes in collagen gels results in a sustained higher expression of key liver transcription factor genes DBP, C/EBP-alpha and -beta, and HNF-1 and -4, as well as specific liver enzyme genes (phosphoenol pyryvate carboxykinase, and carbamoylphosphate-synthetase I).
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Affiliation(s)
- M J Gómez-Lechón
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital La Fe, Valencia, Spain.
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Abstract
Cytochrome P450 (CYP) activity is very low or even absent in human hepatomas, a phenomenon that is accompanied by low levels of some liver transcription factors, notably C/EBP alpha. To investigate a possible link between this transcription factor and hepatic CYP expression, we have stably transfected HepG2 cells with a C/EBP alpha vector containing a Zn-inducible metallothionein promoter. Expression of functional C/EBP alpha up to liver levels concomitantly increased the mRNAs of several members of the CYP2 family (2B6, 2C9 and 2D6), suggesting that this transcription factor may play a relevant role in controlling the hepatic expression of CYP enzymes.
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Affiliation(s)
- R Jover
- Unidad de Hepatología Experimental, Centro de Investigación, Hospital Universitario La Fe, SVS, Valencia, Spain
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Abstract
In the course of biotransformation reactions catalyzed both by cytochrome P450 and by conjugating enzymes, drug-derived reactive metabolites and active oxygen species can appear that may escape the detoxification process, initiating radical chain reactions (e.g., lipid peroxidation), covalently binding to macromolecules (proteins, DNA), or impairing the energetic balance of cells. This is usually followed by alterations of ion homeostasis that precede irreversible biochemical changes and cell death. There are, however, cellular mechanisms of defense that prevent, or repair, the damage caused by these reactive intermediates. Ultimately it is the balance between bioactivation, detoxification, and defense mechanisms that determines whether a compound will or will not elicit a toxic effect. Cultures of hepatocytes, including those of human origin, can be used to elucidate the mechanisms of drug toxicity. This is illustrated in the study of the mechanism of hepatotoxicity by diclofenac. Much less cytotoxicity is observed in nonmetabolizing hepatomas than in hepatocytes. The observed cell dysfunction parallels the biotransformation of the drug, and particularly the formation of the minor metabolite N,5-dihydroxydiclofenac by hepatocytes. This compound is able to inhibit mitochondrial ATP synthesis in hepatocytes.
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Affiliation(s)
- J V Castell
- Unidad de Hepatología Experimental Centro de Investigación, Hospital Universitario La Fe, Valencia, Spain
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Affiliation(s)
- J V Castell
- Unidad de Hepatología Experimental, Hospital Universitario La Fe, Valencia, Spain
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Bort R, Ponsoda X, Carrasco E, Gómez-Lechón MJ, Castell JV. Comparative metabolism of the nonsteroidal antiinflammatory drug, aceclofenac, in the rat, monkey, and human. Drug Metab Dispos 1996; 24:969-75. [PMID: 8886606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Aceclofenac ([2-(2',6'-dichlorophenylamino)phenyl]acetoxyacetic acid) is a novel nonsteroidal antiinflammatory drug, the pharmacokinetics and drug metabolism of which show species differences. After oral administration to the rat, circulating aceclofenac rapidly disappears yielding [2-(2',6'-dichlorophenylamino)phenyl]acetic acid (diclofenac), which is then further oxidized to [2-(2',6'-dichloro-4'-hydroxyphenylamino)phenyl[acetic acid (4'-hydroxydiclofenac) and [2-(2',6'-dichloro-4'-hydroxyphenylamino)phenyl]acetic acid (4'-hydroxydiclofenac) and [2-(2',6'-dichlorophenylamino)-5-hydroxyphenyl]acetic acid (5-hydroxydiclofenac). This is a minor route in humans, wherein aceclofenac is hydroxylated to [2-(2',6'-dichloro-4'-hydroxyphenylamino)phenyl]acetoxyacetic acid (4'-hydroxyaceclofenac), which becomes the major metabolite. In the monkey, the conversion of aceclofenac to diclofenac takes place, but to a much lesser extent than in the rat, and the 4'-hydroxylated metabolites from both compounds are found in monkeys' urine. The mechanistic basis for this species-dependent variations seems to be the different stability of the drug toward liver esterases. In the rat, the most efficient aceclofenac-hydrolyzing activity is found in hepatic microsomes (Vmax = 2113 +/- 177 pmol/min/mg protein and KM = 191 +/- 40 microM) and cytosol (Vmax = 479 +/- 37 pmol/min/mg protein and KM = 75 +/- 22 microM). Consequently, incubation of aceclofenac with cultured rat hepatocytes or in the rat in vivo results in a rapid hydrolysis of the drug, followed by oxidative metabolism of the resulting diclofenac, yielding 4'- and 5-hydroxylated derivatives as the major metabolites. In contrast, the aceclofenac ester bond is much more stable toward human hepatic microsomal (Vmax = 27 +/- 10 pmol/min/mg protein and KM = 792 +/- 498 microM) and cytosolic (Vmax = 87 +/- 5 pmol/min/mg protein and KM 218 +/- 30 microM) esterases, and 4'-hydroxyaceclofenac becomes the major metabolite in cultured human hepatocytes, as well as in human urine. The research presented herein also illustrates the suitability of cultured human hepatocytes for predicting aceclofenac metabolism in humans.
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Affiliation(s)
- R Bort
- Unidad de Hepatología Experimental, Hospital Universitario La Fe, Valencia, Spain
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Bort R, Ponsoda X, Carrasco E, Gómez-Lechón MJ, Castell JV. Metabolism of aceclofenac in humans. Drug Metab Dispos 1996; 24:834-41. [PMID: 8869816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Metabolism of the new nonsteroidal antiinflammatory drug aceclofenac ([2-(2',6'-dichlorophenylamino)phenyl]acetoxyacetic acid) was investigated both in the in vitro hepatic human models and in vivo. Aceclofenac is metabolized in human hepatocytes and human microsomes to form [2-(2',6'-dichloro-4'-hydroxy- phenylamino)phenyl]acetoxyacetic acid as the major metabolite, which is then further conjugated. Minor metabolites were [2-(2',6'-dichlorophenylamino)-5-hydroxyphenyl]acetoxyacetic acid and [2-(2',6'-dichlorophenylamino)phenyl]acetic acid, as well as the hydroxylated derivatives [2-(2',6'-dichloro-4'- hydroxyphenylamino)phenyl]acetic acid and [2-(2',6'-dichlorophenylamino)- 5-hydroxyphenyl]acetic acid. After oral administration to human volunteers (100 mg, single dose), aceclofenac reached a Cmax value of 7.6 +/- 1.3 micrograms/ml and a tmax of 2.6 +/- 1.8. The same metabolites as those detected in cell culture or microsome incubations were found in 12-hr urine after an oral administration of 100 mg aceclofenac to human volunteers. Cytochrome 2C9 is the enzyme responsible for the hydroxylation at position 4'. This could be demonstrated by: 1) selective inhibition by sulfaphenazole; 2) correlation between the formation of the hydroxylated metabolite and tolbutamide hydroxylase activity; and 3) formation of this metabolite only when incubated with microsomes obtained from cells expressing human cytochrome 2C9. However, no conclusive information could be obtained concerning the cytochrome catalyzing the hydroxylation at position 5. The comparison between human microsomes and human hepatocytes metabolism on one hand, and human in vivo metabolism on the other, supports human hepatocytes in primary culture as the model that best anticipated the metabolism of the drug in vivo.
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Affiliation(s)
- R Bort
- Unidad de Hepatología Experimental, Hospital Universitario La Fe, Valencia, Spain
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Bort R, Schinderle DR. Using EDI (electronic data interchange) to improve the accounts payable department. Healthc Financ Manage 1994; 48:78, 80-2, 84. [PMID: 10145937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Additional paperwork, escalating costs, and an outdated accounts payable system at St. Joseph Health System forced management staff to alter the way the accounts payable department operates. This article describes the process the health system used to automate one of its accounts payable departments by using electronic data interchange/electronic funds transfer (EDI/EFT) technology.
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Affiliation(s)
- R Bort
- Center for Healthcare EDI, Sherman Oaks, CA
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Carpenter TO, McPhee MD, Bort R, Mitnick MA, Carnes DL. Dissociation of phosphaturia and 25(OH)D-1 alpha-hydroxylase trophism using a novel analogue of parathyroid hormone. Am J Physiol 1992; 262:E483-7. [PMID: 1314496 DOI: 10.1152/ajpendo.1992.262.4.e483] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Certain parathyroid hormone (PTH) analogues have been shown to selectively impair some but not all physiological actions of PTH. In this study, transaminated rat (r) PTH [TA-rPTH-(1-34)], a PTH analogue that differs from the rPTH-(1-34) fragment in that the NH2-terminal alanine is converted to pyruvate, was infused into mice to determine its properties in vivo and specifically to determine whether stimulation of 25-hydroxyvitamin D-1 alpha-hydroxylase (1 alpha-hydroxylase) activity was more dependent on concomitant renal handling of phosphate or on generation of adenosine 3',5'-cyclic monophosphate (cAMP). High-performance liquid chromatography-purified TA-rPTH-(1-34) was infused into C57BL mice at 10 or 30 pmol/h for 24 h. At 30 pmol/h, TA-rPTH-(1-34) was comparable with rPTH-(1-34) in its hypophosphatemic and phosphaturic effects but was less potent than rPTH-(1-34) in raising serum calcium. TA-rPTH-(1-34) was markedly less effective in stimulating renal 1 alpha-hydroxylase than rPTH-(1-34). Stimulation of urinary cAMP excretion occurred after infusion with TA-rPTH-(1-34), but this effect was significantly less than that seen with rPTH-(1-34). These findings indicate that PTH-induced hypophosphatemia and phosphaturia can be uncoupled from PTH stimulation of 1 alpha-hydroxylase. Furthermore, cAMP-related signal transduction appears to be more significant in regulation of 1 alpha-hydroxylase than mechanisms that mediate PTH-sensitive phosphate transport, independent of cAMP.
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Affiliation(s)
- T O Carpenter
- Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510
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