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Sinha RA, Rajak S, Singh BK, Yen PM. Hepatic Lipid Catabolism via PPARα-Lysosomal Crosstalk. Int J Mol Sci 2020; 21:ijms21072391. [PMID: 32244266 PMCID: PMC7170715 DOI: 10.3390/ijms21072391] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/01/2020] [Accepted: 03/02/2020] [Indexed: 12/13/2022] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors which belong to the nuclear hormone receptor superfamily. They regulate key aspects of energy metabolism within cells. Recently, PPARα has been implicated in the regulation of autophagy-lysosomal function, which plays a key role in cellular energy metabolism. PPARα transcriptionally upregulates several genes involved in the autophagy-lysosomal degradative pathway that participates in lipolysis of triglycerides within the hepatocytes. Interestingly, a reciprocal regulation of PPARα nuclear action by autophagy-lysosomal activity also exists with implications in lipid metabolism. This review succinctly discusses the unique relationship between PPARα nuclear action and lysosomal activity and explores its impact on hepatic lipid homeostasis under pathological conditions such as non-alcoholic fatty liver disease (NAFLD).
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Affiliation(s)
- Rohit A. Sinha
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, India;
- Correspondence: or
| | - Sangam Rajak
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, India;
| | - Brijesh K. Singh
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, Singapore 169587, Singapore (P.M.Y.)
| | - Paul M. Yen
- Program of Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, 8 College Road, Singapore 169587, Singapore (P.M.Y.)
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Ferrín G, Guerrero M, Amado V, Rodríguez-Perálvarez M, De la Mata M. Activation of mTOR Signaling Pathway in Hepatocellular Carcinoma. Int J Mol Sci 2020; 21:ijms21041266. [PMID: 32070029 PMCID: PMC7072933 DOI: 10.3390/ijms21041266] [Citation(s) in RCA: 203] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 12/17/2022] Open
Abstract
Hepatocellular carcinoma (HCC) is the most frequent primary liver cancer and occurs mainly in patients with liver cirrhosis. The mammalian target of rapamycin (mTOR) signaling pathway is involved in many hallmarks of cancer including cell growth, metabolism re-programming, proliferation and inhibition of apoptosis. The mTOR pathway is upregulated in HCC tissue samples as compared with the surrounding liver cirrhotic tissue. In addition, the activation of mTOR is more intense in the tumor edge, thus reinforcing its role in HCC proliferation and spreading. The inhibition of the mTOR pathway by currently available pharmacological compounds (i.e., sirolimus or everolimus) is able to hamper tumor progression both in vitro and in animal models. The use of mTOR inhibitors alone or in combination with other therapies is a very attractive approach, which has been extensively investigated in humans. However, results are contradictory and there is no solid evidence suggesting a true benefit in clinical practice. As a result, neither sirolimus nor everolimus are currently approved to treat HCC or to prevent tumor recurrence after curative surgery. In the present comprehensive review, we analyzed the most recent scientific evidence while providing some insights to understand the gap between experimental and clinical studies.
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Affiliation(s)
- Gustavo Ferrín
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Universidad de Córdoba, 14004 Córdoba, Spain; (G.F.); (M.G.); (V.A.); (M.D.l.M.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), 14004 Córdoba, Spain
| | - Marta Guerrero
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Universidad de Córdoba, 14004 Córdoba, Spain; (G.F.); (M.G.); (V.A.); (M.D.l.M.)
- Department of Hepatology and Liver Transplantaton, Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
| | - Víctor Amado
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Universidad de Córdoba, 14004 Córdoba, Spain; (G.F.); (M.G.); (V.A.); (M.D.l.M.)
- Department of Hepatology and Liver Transplantaton, Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
| | - Manuel Rodríguez-Perálvarez
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Universidad de Córdoba, 14004 Córdoba, Spain; (G.F.); (M.G.); (V.A.); (M.D.l.M.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), 14004 Córdoba, Spain
- Department of Hepatology and Liver Transplantaton, Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
- Correspondence: ; Tel.: +34-617854692
| | - Manuel De la Mata
- Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Universidad de Córdoba, 14004 Córdoba, Spain; (G.F.); (M.G.); (V.A.); (M.D.l.M.)
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), 14004 Córdoba, Spain
- Department of Hepatology and Liver Transplantaton, Hospital Universitario Reina Sofía, 14004 Córdoba, Spain
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Kounakis K, Chaniotakis M, Markaki M, Tavernarakis N. Emerging Roles of Lipophagy in Health and Disease. Front Cell Dev Biol 2019; 7:185. [PMID: 31552248 PMCID: PMC6746960 DOI: 10.3389/fcell.2019.00185] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 08/21/2019] [Indexed: 12/12/2022] Open
Abstract
The term lipophagy is used to describe the autophagic degradation of lipid droplets, the main lipid storage organelles of eukaryotic cells. Ever since its discovery in 2009, lipophagy has emerged as a significant component of lipid metabolism with important implications for organismal health. This review aims to provide a brief summary of our current knowledge on the mechanisms that are responsible for regulating lipophagy and the impact the process has under physiological and pathological conditions.
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Affiliation(s)
- Konstantinos Kounakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
| | - Manos Chaniotakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Chemistry, University of Crete, Heraklion, Greece
| | - Maria Markaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece
| | - Nektarios Tavernarakis
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology - Hellas, Heraklion, Greece.,Department of Basic Sciences, Medical School, University of Crete, Heraklion, Greece
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Abstract
Lipid droplets (LDs) are key sites of neutral lipid storage that can be found in all cells. Metabolic imbalances between the synthesis and degradation of LDs can result in the accumulation of significant amounts of lipid deposition, a characteristic feature of hepatocytes in patients with fatty liver disease, a leading indication for liver transplant in the United States. In this review, the authors highlight new literature related to the synthesis and autophagic catabolism of LDs, discussing key proteins and machinery involved in these processes. They also discuss recent findings that have revealed novel genetic risk factors associated with LD biology that contribute to lipid retention in the diseased liver.
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Affiliation(s)
- Ryan J. Schulze
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, Rochester, Minnesota
| | - Mark A. McNiven
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, Rochester, Minnesota
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Yan S, Zhou J, Chen X, Dong Z, Yin XM. Diverse Consequences in Liver Injury in Mice with Different Autophagy Functional Status Treated with Alcohol. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:1744-1762. [PMID: 31199920 DOI: 10.1016/j.ajpath.2019.05.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/01/2019] [Accepted: 05/07/2019] [Indexed: 02/07/2023]
Abstract
Alcoholic fatty liver disease is often complicated by other pathologic insults, such as viral infection or high-fat diet. Autophagy plays a homeostatic role in the liver but can be compromised by alcohol, high-fat diet, or viral infection, which in turn affects the disease process caused by these etiologies. To understand the full impact of autophagy modulation on alcohol-induced liver injury, several genetic models of autophagy deficiency, which have different levels of functional alterations, were examined after acute binge or chronic-plus-binge treatment. Mice given alcohol with either mode and induced with deficiency in liver-specific Atg7 shortly after the induction of Atg7 deletion had elevated liver injury, indicating the protective role of autophagy. Constitutive hepatic Atg7-deficient mice, in which Atg7 was deleted in embryos, were more susceptible with chronic-plus-binge but not with acute alcohol treatment. Constitutive hepatic Atg5-deficient mice, in which Atg5 was deleted in embryos, were more susceptible with acute alcohol treatment, but liver injury was unexpectedly improved with the chronic-plus-binge regimen. A prolonged autophagy deficiency may complicate the hepatic response to alcohol treatment, likely in part due to endogenous liver injury. The complexity of the relationship between autophagy deficiency and alcohol-induced liver injury can thus be affected by the timing of autophagy dysfunction, the exact autophagy gene being affected, and the alcohol treatment regimen.
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Affiliation(s)
- Shengmin Yan
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Jun Zhou
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Minimal Invasive Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoyun Chen
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Zheng Dong
- Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, China; Department of Cell Biology and Anatomy, Medical College of Georgia and Charlie Norwood Veterans Affairs Medical Center, Augusta, Georgia
| | - Xiao-Ming Yin
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, Indiana; Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, China.
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Zhou XL, Wan XM, Fu XX, Xie CG. Puerarin prevents cadmium-induced hepatic cell damage by suppressing apoptosis and restoring autophagic flux. Biomed Pharmacother 2019; 115:108929. [PMID: 31060001 DOI: 10.1016/j.biopha.2019.108929] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/22/2019] [Accepted: 04/26/2019] [Indexed: 01/05/2023] Open
Abstract
Cadmium (Cd) is a common heavy metal contamination that is highly toxic to liver. Puerarin (PU), a potent free radical scavenger, has been shown to exert cytoprotective effect in numerous pathological processes. However, whether PU affords protection against Cd-induced hepatotoxicity remains unclear to be known. Here, we aimed to investigate the protective effect of PU on Cd-induced hepatotoxicity in an immortalized mouse hepatocyte line, AML-12. First, Cd-induced cytotoxicity in AML-12 cells was obviously ameliorated by PU treatment. Also, Cd-induced apoptotic cell death was markedly alleviated by PU treatment, evidenced by two methods. Simultaneously, Cd-elevated malondialdehyde and reactive oxygen species levels were significantly reduced by PU administration, demonstrating the antioxidant effect of PU against Cd exposure. Moreover, Cd-induced blockage of autophagic flux in AML-12 cells was obviously restored by PU treatment, evidenced by immunoblot analysis of autophagy marker proteins and tandem fluorescent-tagged LC3 method. Resultantly, Cd-induced autophagosome accumulation was significantly alleviated by PU treatment. In conclusion, these observations demonstrate that PU treatment alleviates Cd-induced hepatic cell damage by inhibiting apoptosis and restoring autophagy activity, which is intimately related with its antioxidant activity.
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Affiliation(s)
- Xue-Lei Zhou
- Hospital of Chengdu University of Traditional Chinese Medicine, No. 39 Shi-er-qiao Road, Chengdu, 610072, Sichuan Province, PR China; Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611130, PR China
| | - Xue-Mei Wan
- Hospital of Chengdu University of Traditional Chinese Medicine, No. 39 Shi-er-qiao Road, Chengdu, 610072, Sichuan Province, PR China; Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611130, PR China
| | - Xiao-Xu Fu
- Hospital of Chengdu University of Traditional Chinese Medicine, No. 39 Shi-er-qiao Road, Chengdu, 610072, Sichuan Province, PR China; Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611130, PR China
| | - Chun-Guang Xie
- Hospital of Chengdu University of Traditional Chinese Medicine, No. 39 Shi-er-qiao Road, Chengdu, 610072, Sichuan Province, PR China; Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan 611130, PR China.
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Yin XM. Autophagy in liver diseases: A matter of what to remove and whether to keep. LIVER RESEARCH 2018; 2:109-111. [PMID: 32042470 PMCID: PMC7010265 DOI: 10.1016/j.livres.2018.09.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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