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Noncanonical Constitutive Androstane Receptor Signaling in Gene Regulation. Int J Mol Sci 2020; 21:ijms21186735. [PMID: 32937916 PMCID: PMC7555422 DOI: 10.3390/ijms21186735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 09/04/2020] [Accepted: 09/10/2020] [Indexed: 11/17/2022] Open
Abstract
The constitutive androstane receptor (CAR, NR1I3) is extremely important for the regulation of many physiological processes, especially xenobiotic (drug) metabolism and transporters. CAR differs from steroid hormone receptors in that it can be activated using structurally unrelated chemicals, both through direct ligand-binding and ligand-independent (indirect) mechanisms. By binding to specific responsive elements on DNA, CAR increases the expression of its target genes encoding drug-metabolizing enzymes and transporters. Therefore, CAR is mainly characterized as a ligand-dependent or ligand-independent transcription factor, and the induction of gene expression is considered the canonical mode of CAR action. Consistent with its central role in xenobiotic metabolism, CAR signaling includes a collection of mechanisms that are employed alongside the core transcriptional machinery of the receptor. These so-called noncanonical CAR pathways allow the receptor to coordinate the regulation of many aspects of cell biology. In this mini-review, we review noncanonical CAR signaling, paying special attention to the role of CAR in energy homeostasis and cell proliferation.
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Pibiri M, Sulas P, Leoni VP, Perra A, Kowalik MA, Cordella A, Saggese P, Nassa G, Ravo M. Global gene expression profile of normal and regenerating liver in young and old mice. AGE (DORDRECHT, NETHERLANDS) 2015; 37:9796. [PMID: 26036689 PMCID: PMC4451458 DOI: 10.1007/s11357-015-9796-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 05/21/2015] [Indexed: 06/04/2023]
Abstract
The ability of the liver to regenerate and adjust its size after two/third partial hepatectomy (PH) is impaired in old rodents and humans. Here, we investigated by microarray analysis the expression pattern of hepatic genes in young and old untreated mice and the differences in gene expression profile following PH. Of the 10,237 messenger RNAs that had detectable expression, only 108 displayed a greater than 2-fold modification in gene expression levels between the two groups. These genes were involved in inflammatory and immune response, xenobiotics, and lipid and glucose metabolism. To identify the genes responsible for the different regenerative response, 10-week and 18-month-old mice subjected to PH were sacrificed at different time intervals after surgery. The results showed that 2463 transcripts had significantly different expression post PH between the two groups. However, in spite of impaired liver regeneration in old mice, cell cycle genes were similarly modified in both groups, the only exception being cyclin D1 gene which was up-regulated soon after PH in young mice, but mostly down-regulated in aged animals. Surprisingly, while in young hepatectomized mice, Yap messenger RNA (mRNA) expression was not significantly enhanced and protein expression essentially reflected the progression into cell cycle, its mRNA and protein levels were robustly increased in the liver of aged animals. Furthermore, a significant change of the age-related expression of the size regulator Yes-associated protein (YAP) was observed. Unexpectedly, while in young hepatectomized mice, Yap mRNA expression was not significantly enhanced and protein expression essentially reflected the progression into cell cycle, its mRNA and protein levels were robustly increased in the liver of aged animals. Moreover, when PH was performed on mitogen-induced enlarged livers, the earlier restoration of the original liver mass compared to animals subjected to PH only led to YAP down-regulation concomitantly with cyclin D1 up-regulation. Our data suggest that YAP activation is a size-dependent homeostatic mechanism that does not necessarily reflect cell cycle progression.
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Affiliation(s)
- Monica Pibiri
- />Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Via Porcell 4, Cagliari, Italy
| | - Pia Sulas
- />Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Via Porcell 4, Cagliari, Italy
| | - Vera Piera Leoni
- />Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Via Porcell 4, Cagliari, Italy
| | - Andrea Perra
- />Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Via Porcell 4, Cagliari, Italy
| | - Marta Anna Kowalik
- />Department of Biomedical Sciences, Unit of Oncology and Molecular Pathology, University of Cagliari, Via Porcell 4, Cagliari, Italy
| | | | - Pasquale Saggese
- />Laboratory of Molecular Medicine and Genomics, Department of Medicine and Surgery, University of Salerno, Via S. Allende, 1, Baronissi, Italy
- />Genomix4Life Srl, Spin-Off of the Laboratory of Molecular Medicine and Genomics, University of Salerno, Baronissi, Italy
| | - Giovanni Nassa
- />Laboratory of Molecular Medicine and Genomics, Department of Medicine and Surgery, University of Salerno, Via S. Allende, 1, Baronissi, Italy
| | - Maria Ravo
- />Laboratory of Molecular Medicine and Genomics, Department of Medicine and Surgery, University of Salerno, Via S. Allende, 1, Baronissi, Italy
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Bugyik E, Dezso K, Turányi E, Szurián K, Paku S, Nagy P. 1,4-Bis[2-(3,5-dichloropyridyloxy)]benzene induces substantial hyperplasia in fibrotic mouse liver. Int J Exp Pathol 2012; 93:125-9. [PMID: 22243368 DOI: 10.1111/j.1365-2613.2011.00803.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The proliferative response of hepatocytes in vivo can be induced by two mechanisms: severe damage to hepatic tissue results in regenerative growth and so-called primary hepatocyte mitogens can initiate liver cell proliferation without preceding loss of parenchyma. The regulation of the two responses is quite different. The decreased regenerative response of cirrhotic/fibrotic liver is well known, and is a severe obstacle to surgery of the diseased liver. In the present experiments we investigated the efficiency of a primary hepatocyte mitogen 1,4-Bis[2-(3,5-dichloropyridyloxy)]benzene (TCPOBOB) on two different liver cirrhosis/fibrosis models in mice induced by chronic administration of CCl(4) and thioacetamide respectively. BrdU incorporation and cyclin A expression established clearly that there is a reduced but still powerful mitogenic response of the fibrotic livers. Therefore, primary hepatocyte mitogens appear to be suitable to be used to rescue the regenerative response of cirrhotic livers.
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Affiliation(s)
- Edina Bugyik
- First Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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Turányi E, Dezso K, Bugyik E, Szurián K, Paku S, Nagy P. The primary mitogen (TCPOBOP)-induced hepatocyte proliferation is resistant to transforming growth factor- β-1 inhibition. Liver Int 2010; 30:1505-10. [PMID: 21040405 DOI: 10.1111/j.1478-3231.2010.02324.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Transforming growth factor (TGF)-β-1 is a very efficient inhibitor of hepatocyte proliferation in various in vivo and in vitro experimental systems. However, there are no data on whether it can influence the mitogenic response induced by primary hepatocyte mitogens. AIMS In this study, we compared the proliferative response in the liver between wild-type and transgenic mice, overexpressing active TGF-β-1 in their liver following the treatment by a primary hepatocyte mitogen TCPOBOP (1,4-bis[2-(3,5-dichloropyridyloxy)]benzene). METHODS The proliferative response was characterized by the immunohistochemical examination of pulse and cumulative bromodeoxyuridine labelling and by quantitative real-time polymerase chain reaction analysis of cell cycle-related genes. RESULTS Neither of the applied techniques revealed significant differences between the two groups of mice; furthermore, we observed the upregulation of TGF-β-1 expression following the mitogenic treatment. CONCLUSIONS TGF-β-1 does not inhibit the primary mitogen-induced proliferative response of the hepatocytes. This observation may provide an explanation for the divergent consequences of hepatic proliferations induced by partial hepatectomy or primary mitogenic treatment.
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Affiliation(s)
- Eszter Turányi
- First Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary
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