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Springer MZ, Poole LP, Drake LE, Bock-Hughes A, Boland ML, Smith AG, Hart J, Chourasia AH, Liu I, Bozek G, Macleod KF. BNIP3-dependent mitophagy promotes cytosolic localization of LC3B and metabolic homeostasis in the liver. Autophagy 2021; 17:3530-3546. [PMID: 33459136 DOI: 10.1080/15548627.2021.1877469] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [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: 12/19/2022] Open
Abstract
Mitophagy formed the basis of the original description of autophagy by Christian de Duve when he demonstrated that GCG (glucagon) induced macroautophagic/autophagic turnover of mitochondria in the liver. However, the molecular basis of liver-specific activation of mitophagy by GCG, or its significance for metabolic stress responses in the liver is not understood. Here we show that BNIP3 is required for GCG-induced mitophagy in the liver through interaction with processed LC3B; an interaction that is also necessary to localize LC3B out of the nucleus to cytosolic mitophagosomes in response to nutrient deprivation. Loss of BNIP3-dependent mitophagy caused excess mitochondria to accumulate in the liver, disrupting metabolic zonation within the liver parenchyma, with expansion of zone 1 metabolism at the expense of zone 3 metabolism. These results identify BNIP3 as a regulator of metabolic homeostasis in the liver through its effect on mitophagy and mitochondrial mass distribution.
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Affiliation(s)
- Maya Z Springer
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA.,The Committee on Cancer Biology, The University of Chicago, Chicago, IL, USA
| | - Logan P Poole
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA.,The Committee on Cancer Biology, The University of Chicago, Chicago, IL, USA
| | - Lauren E Drake
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA
| | - Althea Bock-Hughes
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA.,The University of Chicago, Chicago, IL, USA
| | - Michelle L Boland
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA.,The University of Chicago, Chicago, IL, USA
| | - Alexandra G Smith
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA.,The Committee on Cancer Biology, The University of Chicago, Chicago, IL, USA
| | - John Hart
- Department of Pathology, University of Chicago, Chicago, USA
| | - Aparajita H Chourasia
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA.,The Committee on Cancer Biology, The University of Chicago, Chicago, IL, USA
| | - Ivan Liu
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA
| | - Grazyna Bozek
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA
| | - Kay F Macleod
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338 the University of Chicago, Chicago, IL, USA.,The Committee on Cancer Biology, The University of Chicago, Chicago, IL, USA.,The University of Chicago, Chicago, IL, USA
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2
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Boland ML, Laker RC, Mather K, Nawrocki A, Oldham S, Boland BB, Lewis H, Conway J, Naylor J, Guionaud S, Feigh M, Veidal SS, Lantier L, McGuinness OP, Grimsby J, Rondinone CM, Jermutus L, Larsen MR, Trevaskis JL, Rhodes CJ. Resolution of NASH and hepatic fibrosis by the GLP-1R/GcgR dual-agonist Cotadutide via modulating mitochondrial function and lipogenesis. Nat Metab 2020; 2:413-431. [PMID: 32478287 PMCID: PMC7258337 DOI: 10.1038/s42255-020-0209-6] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Non-alcoholic fatty liver disease and steatohepatitis are highly associated with obesity and type 2 diabetes mellitus. Cotadutide, a GLP-1R/GcgR agonist, was shown to reduce blood glycemia, body weight and hepatic steatosis in patients with T2DM. Here, we demonstrate that the effects of Cotadutide to reduce body weight, food intake and improve glucose control are predominantly mediated through the GLP-1 signaling, while, its action on the liver to reduce lipid content, drive glycogen flux and improve mitochondrial turnover and function are directly mediated through Gcg signaling. This was confirmed by the identification of phosphorylation sites on key lipogenic and glucose metabolism enzymes in liver of mice treated with Cotadutide. Complementary metabolomic and transcriptomic analyses implicated lipogenic, fibrotic and inflammatory pathways, which are consistent with a unique therapeutic contribution of GcgR agonism by Cotadutide in vivo. Significantly, Cotadutide also alleviated fibrosis to a greater extent than Liraglutide or Obeticholic acid (OCA), despite adjusting dose to achieve similar weight loss in 2 preclinical mouse models of NASH. Thus Cotadutide, via direct hepatic (GcgR) and extra-hepatic (GLP-1R) effects, exerts multi-factorial improvement in liver function and is a promising therapeutic option for the treatment of steatohepatitis.
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Affiliation(s)
- Michelle L Boland
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Rhianna C Laker
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Karly Mather
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Arkadiusz Nawrocki
- Department of Biochemistry and Molecular Biology, PR group, University of Southern Denmark, Odense, Denmark
| | - Stephanie Oldham
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Brandon B Boland
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Hilary Lewis
- Research and Early Development, Oncology, AstraZeneca, Cambridge, UK
| | - James Conway
- Translational Sciences, AstraZeneca, Gaithersburg, MD, USA
| | - Jacqueline Naylor
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | | | | | | | - Louise Lantier
- Vanderbilt University Mouse Metabolic Phenotyping Center, Nashville, TN, USA
| | - Owen P McGuinness
- Vanderbilt University Mouse Metabolic Phenotyping Center, Nashville, TN, USA
| | - Joseph Grimsby
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Cristina M Rondinone
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
| | - Lutz Jermutus
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Cambridge, UK
| | - Martin R Larsen
- Department of Biochemistry and Molecular Biology, PR group, University of Southern Denmark, Odense, Denmark
| | - James L Trevaskis
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA
- Gilead Sciences, Foster City, CA, USA
| | - Christopher J Rhodes
- Research and Early Development, Cardiovascular, Renal and Metabolic Diseases, BioPharmaceuticals R&D, AstraZeneca, Gaithersburg, MD, USA.
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3
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Boland ML, Oró D, Tølbøl KS, Thrane ST, Nielsen JC, Cohen TS, Tabor DE, Fernandes F, Tovchigrechko A, Veidal SS, Warrener P, Sellman BR, Jelsing J, Feigh M, Vrang N, Trevaskis JL, Hansen HH. Towards a standard diet-induced and biopsy-confirmed mouse model of non-alcoholic steatohepatitis: Impact of dietary fat source. World J Gastroenterol 2019; 25:4904-4920. [PMID: 31543682 PMCID: PMC6737317 DOI: 10.3748/wjg.v25.i33.4904] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/28/2019] [Accepted: 07/19/2019] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The trans-fat containing AMLN (amylin liver non-alcoholic steatohepatitis, NASH) diet has been extensively validated in C57BL/6J mice with or without the Lepob/Lepob (ob/ob) mutation in the leptin gene for reliably inducing metabolic and liver histopathological changes recapitulating hallmarks of NASH. Due to a recent ban on trans-fats as food additive, there is a marked need for developing a new diet capable of promoting a compatible level of disease in ob/ob and C57BL/6J mice.
AIM To develop a biopsy-confirmed mouse model of NASH based on an obesogenic diet with trans-fat substituted by saturated fat.
METHODS Male ob/ob mice were fed AMLN diet or a modified AMLN diet with trans-fat (Primex shortening) substituted by equivalent amounts of palm oil [Gubra amylin NASH, (GAN) diet] for 8, 12 and 16 wk. C57BL/6J mice were fed the same diets for 28 wk. AMLN and GAN diets had similar caloric content (40% fat kcal), fructose (22%) and cholesterol (2%) level.
RESULTS The GAN diet was more obesogenic compared to the AMLN diet and impaired glucose tolerance. Biopsy-confirmed steatosis, lobular inflammation, hepatocyte ballooning, fibrotic liver lesions and hepatic transcriptome changes were similar in ob/ob mice fed the GAN or AMLN diet. C57BL/6J mice developed a mild to moderate fibrotic NASH phenotype when fed the same diets.
CONCLUSION Substitution of Primex with palm oil promotes a similar phenotype of biopsy-confirmed NASH in ob/ob and C57BL/6J mice, making GAN diet-induced obese mouse models suitable for characterizing novel NASH treatments.
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Affiliation(s)
- Michelle L Boland
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
- Pharmacology, Gubra, Hørsholm DK-2970, Denmark
| | - Denise Oró
- Pharmacology, Gubra, Hørsholm DK-2970, Denmark
| | | | | | | | - Taylor S Cohen
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
| | - David E Tabor
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
| | - Fiona Fernandes
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
| | - Andrey Tovchigrechko
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
| | | | - Paul Warrener
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
| | - Bret R Sellman
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
| | | | | | - Niels Vrang
- Pharmacology, Gubra, Hørsholm DK-2970, Denmark
| | - James L Trevaskis
- Cardiovascular, Renal and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, United States
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Oldham S, Rivera C, Boland ML, Trevaskis JL. Incorporation of a Survivable Liver Biopsy Procedure in Mice to Assess Non-alcoholic Steatohepatitis (NASH) Resolution. J Vis Exp 2019. [DOI: 10.3791/59130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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5
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Boland BB, Brown C, Boland ML, Cann J, Sulikowski M, Hansen G, Grønlund RV, King W, Rondinone C, Trevaskis J, Rhodes CJ, Grimsby JS. Pancreatic β-Cell Rest Replenishes Insulin Secretory Capacity and Attenuates Diabetes in an Extreme Model of Obese Type 2 Diabetes. Diabetes 2019; 68:131-140. [PMID: 30305366 DOI: 10.2337/db18-0304] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [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] [Received: 03/14/2018] [Accepted: 09/27/2018] [Indexed: 11/13/2022]
Abstract
The onset of common obesity-linked type 2 diabetes (T2D) is marked by exhaustive failure of pancreatic β-cell functional mass to compensate for insulin resistance and increased metabolic demand, leading to uncontrolled hyperglycemia. Here, the β-cell-deficient obese hyperglycemic/hyperinsulinemic KS db/db mouse model was used to assess consequential effects on β-cell functional recovery by lowering glucose homeostasis and/or improving insulin sensitivity after treatment with thiazolidinedione therapy or glucagon-like peptide 1 receptor agonism alone or in combination with sodium/glucose cotransporter 2 inhibition (SGLT-2i). SGLT-2i combination therapies improved glucose homeostasis, independent of changes in body weight, resulting in a synergistic increase in pancreatic insulin content marked by significant recovery of the β-cell mature insulin secretory population but with limited changes in β-cell mass and no indication of β-cell dedifferentiation. Restoration of β-cell insulin secretory capacity also restored biphasic insulin secretion. These data emphasize that by therapeutically alleviating the demand for insulin in vivo, irrespective of weight loss, endogenous β-cells recover significant function that can contribute to attenuating diabetes. Thus, this study provides evidence that alleviation of metabolic demand on the β-cell, rather than targeting the β-cell itself, could be effective in delaying the progression of T2D.
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Affiliation(s)
- Brandon B Boland
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
- Gubra ApS, Hørsholm, Denmark
| | - Charles Brown
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Michelle L Boland
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
- Gubra ApS, Hørsholm, Denmark
| | - Jennifer Cann
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Michal Sulikowski
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | | | | | - Wanda King
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Cristina Rondinone
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - James Trevaskis
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Christopher J Rhodes
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
| | - Joseph S Grimsby
- Division of Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, MD
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6
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Boland ML, Oldham S, Boland BB, Will S, Lapointe JM, Guionaud S, Rhodes CJ, Trevaskis JL. Nonalcoholic steatohepatitis severity is defined by a failure in compensatory antioxidant capacity in the setting of mitochondrial dysfunction. World J Gastroenterol 2018; 24:1748-1765. [PMID: 29713129 PMCID: PMC5922994 DOI: 10.3748/wjg.v24.i16.1748] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 02/22/2018] [Accepted: 02/25/2018] [Indexed: 02/06/2023] Open
Abstract
AIM To comprehensively evaluate mitochondrial (dys) function in preclinical models of nonalcoholic steatohepatitis (NASH).
METHODS We utilized two readily available mouse models of nonalcoholic fatty liver disease (NAFLD) with or without progressive fibrosis: Lepob/Lepob (ob/ob) and FATZO mice on high trans-fat, high fructose and high cholesterol (AMLN) diet. Presence of NASH was assessed using immunohistochemical and pathological techniques, and gene expression profiling. Morphological features of mitochondria were assessed via transmission electron microscopy and immunofluorescence, and function was assessed by measuring oxidative capacity in primary hepatocytes, and respiratory control and proton leak in isolated mitochondria. Oxidative stress was measured by assessing activity and/or expression levels of Nrf1, Sod1, Sod2, catalase and 8-OHdG.
RESULTS When challenged with AMLN diet for 12 wk, ob/ob and FATZO mice developed steatohepatitis in the presence of obesity and hyperinsulinemia. NASH development was associated with hepatic mitochondrial abnormalities, similar to those previously observed in humans, including mitochondrial accumulation and increased proton leak. AMLN diet also resulted in increased numbers of fragmented mitochondria in both strains of mice. Despite similar mitochondrial phenotypes, we found that ob/ob mice developed more advanced hepatic fibrosis. Activity of superoxide dismutase (SOD) was increased in ob/ob AMLN mice, whereas FATZO mice displayed increased catalase activity, irrespective of diet. Furthermore, 8-OHdG, a marker of oxidative DNA damage, was significantly increased in ob/ob AMLN mice compared to FATZO AMLN mice. Therefore, antioxidant capacity reflected as the ratio of catalase:SOD activity was similar between FATZO and C57BL6J control mice, but significantly perturbed in ob/ob mice.
CONCLUSION Oxidative stress, and/or the capacity to compensate for increased oxidative stress, in the setting of mitochondrial dysfunction, is a key factor for development of hepatic injury and fibrosis in these mouse models.
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Affiliation(s)
- Michelle L Boland
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - Stephanie Oldham
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - Brandon B Boland
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - Sarah Will
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | | | - Silvia Guionaud
- Pathology, Drug Safety and Metabolism, IMED Biotech Unit, AstraZeneca, Cambridge CB22 3AT, United Kingdom
| | - Christopher J Rhodes
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
| | - James L Trevaskis
- Cardiovascular and Metabolic Diseases, MedImmune LLC, Gaithersburg, MD 20878, United States
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7
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Jouihan H, Will S, Guionaud S, Boland ML, Oldham S, Ravn P, Celeste A, Trevaskis JL. Superior reductions in hepatic steatosis and fibrosis with co-administration of a glucagon-like peptide-1 receptor agonist and obeticholic acid in mice. Mol Metab 2017; 6:1360-1370. [PMID: 29107284 PMCID: PMC5681275 DOI: 10.1016/j.molmet.2017.09.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 08/30/2017] [Accepted: 09/05/2017] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Nonalcoholic steatohepatitis (NASH) is an unmet need associated with metabolic syndrome. There are no approved therapies for NASH; however, glucagon-like peptide-1 receptor (GLP-1R) and farnesoid-X receptor (FXR) agonists are promising drug targets. We investigated the therapeutic effects of co-administration of a GLP-1R agonist, IP118, with FXR agonist obeticholic acid (OCA) in mice. METHODS OCA and IP118 alone and in combination were sub-chronically administered to Lepob/Lepob mice with diet-induced NASH or diet-induced obese (DIO) mice. Metabolic (body weight and glucose) and liver (biochemical and histological) endpoints were assessed. NASH severity in Lepob/Lepob mice was graded using a customized integrated scoring system. RESULTS OCA reduced liver weight and lipid in NASH mice (both by -17%) but had no effect on plasma ALT or AST levels. In contrast, IP118 significantly reduced liver weight (-21%), liver lipid (-15%), ALT (-29%), and AST (-27%). The combination of OCA + IP118 further reduced liver weight (-29%), liver lipid (-22%), ALT (-39%), and AST (-36%). Combination therapy was superior to monotherapies in reducing hepatic steatosis, inflammation, and fibrosis. Hepatic improvements with IP118 and OCA + IP118 were associated with reduced body weight (-4.3% and -3.5% respectively) and improved glycemic control in OCA + IP118-treated mice. In DIO mice, OCA + IP118 co-administration reduced body weight (-25.3%) to a greater degree than IP118 alone (-12.5%) and further improved glucose tolerance and reduced hepatic lipid. CONCLUSION Our data suggest a complementary or synergistic therapeutic effect of GLP-1R and FXR agonism in mouse models of metabolic disease and NASH.
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Affiliation(s)
- Hani Jouihan
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | - Sarah Will
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | | | - Michelle L Boland
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | - Stephanie Oldham
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA
| | - Peter Ravn
- Antibody Discovery and Protein Engineering, MedImmune Ltd, Cambridge, UK
| | | | - James L Trevaskis
- Cardiovascular and Metabolic Diseases, MedImmune, LLC, Gaithersburg, MD, USA.
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8
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Chourasia AH, Tracy K, Frankenberger C, Boland ML, Sharifi MN, Drake LE, Sachleben JR, Asara JM, Locasale JW, Karczmar GS, Macleod KF. Mitophagy defects arising from BNip3 loss promote mammary tumor progression to metastasis. EMBO Rep 2015; 16:1145-63. [PMID: 26232272 PMCID: PMC4576983 DOI: 10.15252/embr.201540759] [Citation(s) in RCA: 212] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 07/08/2015] [Accepted: 07/09/2015] [Indexed: 12/20/2022] Open
Abstract
BNip3 is a hypoxia-inducible protein that targets mitochondria for autophagosomal degradation. We report a novel tumor suppressor role for BNip3 in a clinically relevant mouse model of mammary tumorigenesis. BNip3 delays primary mammary tumor growth and progression by preventing the accumulation of dysfunctional mitochondria and resultant excess ROS production. In the absence of BNip3, mammary tumor cells are unable to reduce mitochondrial mass effectively and elevated mitochondrial ROS increases the expression of Hif-1α and Hif target genes, including those involved in glycolysis and angiogenesis—two processes that are also markedly increased in BNip3-null tumors. Glycolysis inhibition attenuates the growth of BNip3-null tumor cells, revealing an increased dependence on autophagy for survival. We also demonstrate that BNIP3 deletion can be used as a prognostic marker of tumor progression to metastasis in human triple-negative breast cancer (TNBC). These studies show that mitochondrial dysfunction—caused by defects in mitophagy—can promote the Warburg effect and tumor progression, and suggest better approaches to stratifying TNBC for treatment.
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Affiliation(s)
- Aparajita H Chourasia
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA The Committee on Cancer Biology, Chicago, IL, USA
| | - Kristin Tracy
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA The Committee on Cancer Biology, Chicago, IL, USA
| | - Casey Frankenberger
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA
| | - Michelle L Boland
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA The Committee on Molecular Metabolism and Nutrition, Chicago, IL, USA
| | - Marina N Sharifi
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA The Committee on Cancer Biology, Chicago, IL, USA
| | - Lauren E Drake
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA The Committee on Molecular Pathogenesis & Molecular Medicine, Chicago, IL, USA
| | | | - John M Asara
- Division of Signal Transduction, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Jason W Locasale
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | | | - Kay F Macleod
- The Ben May Department for Cancer Research, The University of Chicago, Chicago, IL, USA The Committee on Cancer Biology, Chicago, IL, USA The Committee on Molecular Metabolism and Nutrition, Chicago, IL, USA
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9
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Abstract
Mitophagy is a selective form of macro-autophagy in which mitochondria are selectively targeted for degradation in autophagolysosomes. Mitophagy can have the beneficial effect of eliminating old and/or damaged mitochondria, thus maintaining the integrity of the mitochondrial pool. However, mitophagy is not only limited to the turnover of dysfunctional mitochondria but also promotes reduction of overall mitochondrial mass in response to certain stresses, such as hypoxia and nutrient starvation. This prevents generation of reactive oxygen species and conserves valuable nutrients (such as oxygen) from being consumed inefficiently, thereby promoting cellular survival under conditions of energetic stress. The failure to properly modulate mitochondrial turnover in response to oncogenic stresses has been implicated both positively and negatively in tumorigenesis, while the potential of targeting mitophagy specifically as opposed to autophagy in general as a therapeutic strategy remains to be explored. The challenges and opportunities that come with our heightened understanding of the role of mitophagy in cancer are reviewed here.
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Affiliation(s)
- Aparajita H Chourasia
- The Ben May Department for Cancer Research, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 USA ; The Committee on Cancer Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 USA
| | - Michelle L Boland
- The Ben May Department for Cancer Research, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 USA ; The Committee on Molecular Metabolism & Nutrition, 929 East 57th Street, Chicago, IL 60637 USA
| | - Kay F Macleod
- The Ben May Department for Cancer Research, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 USA ; The Committee on Cancer Biology, The University of Chicago, 929 East 57th Street, Chicago, IL 60637 USA ; The Committee on Molecular Metabolism & Nutrition, 929 East 57th Street, Chicago, IL 60637 USA ; The Ben May Department for Cancer Research, The University of Chicago Comprehensive Cancer Center, The Gordon Center for Integrative Sciences, W338 929 East 57th Street, Chicago, IL 60637 USA
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10
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Boland ML, Huang H, Shah R, Ali A, Zhao Y, Rhodes CJ, Macleod KF. Abstract 4324: BNip3 connects energy sensing to hepatic lipid metabolism and mitophagy. Cancer Res 2014. [DOI: 10.1158/1538-7445.am2014-4324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
BNip3 is a hypoxia-inducible member of the Bcl-2 family that integrates into the outer mitochondrial membrane as stable homodimers where it acts as a receptor for mitochondrial engulfment through a conserved LC3 interacting region. Hepatic BNip3 levels are constitutively elevated relative to other tissues, and dramatically increase upon nutrient deprivation or glucagon stimulation, suggesting a key role for BNip3 in the fasting response. We have determined that the fasting-induced increase in hepatic BNip3 protein levels is not solely attributable to transcriptional induction and have identified post-translational modification of BNip3 that affects protein stability and function. In a mouse model of BNip3 loss, we observe metabolic defects including increased hepatic lipid synthesis and reduced fatty acid oxidation. Consistent with BNip3's role in mitophagy, defects in liver metabolism were linked to increased mitochondrial mass, but decreased mitochondrial function, including reduced oxygen consumption and loss of mitochondrial membrane potential. Delivery of a mitophagy deficient mutant BNip3 to the BNip3 null liver indicates that defects in lipid metabolism are not simply due to the accumulation of defective mitochondria, but rather BNip3 has another role to regulate lipid metabolism based on nutrient status. Of relevance, BNip3 is epigenetically silenced in the more aggressive and common form of HCC (sub-type A) and thus this work identifies potential mechanisms by which this protein may act as a tumor suppressor.
Citation Format: Michelle L. Boland, He Huang, Ramilla Shah, Almas Ali, Yingming Zhao, Christopher J. Rhodes, Kay F. Macleod. BNip3 connects energy sensing to hepatic lipid metabolism and mitophagy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4324. doi:10.1158/1538-7445.AM2014-4324
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Affiliation(s)
| | - He Huang
- University of Chicago, Chicago, IL
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11
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Abstract
A mechanistic understanding of how mitochondrial dysfunction contributes to cell growth and tumorigenesis is emerging beyond Warburg as an area of research that is under-explored in terms of its significance for clinical management of cancer. Work discussed in this review focuses less on the Warburg effect and more on mitochondria and how dysfunctional mitochondria modulate cell cycle, gene expression, metabolism, cell viability, and other established aspects of cell growth and stress responses. There is increasing evidence that key oncogenes and tumor suppressors modulate mitochondrial dynamics through important signaling pathways and that mitochondrial mass and function vary between tumors and individuals but the significance of these events for cancer are not fully appreciated. We explore the interplay between key molecules involved in mitochondrial fission and fusion and in apoptosis, as well as in mitophagy, biogenesis, and spatial dynamics of mitochondria and consider how these distinct mechanisms are coordinated in response to physiological stresses such as hypoxia and nutrient deprivation. Importantly, we examine how deregulation of these processes in cancer has knock on effects for cell proliferation and growth. We define major forms of mitochondrial dysfunction and address the extent to which the functional consequences of such dysfunction can be determined and exploited for cancer diagnosis and treatment.
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Affiliation(s)
- Michelle L Boland
- The Ben May Department for Cancer Research, The University of Chicago , Chicago, IL , USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago , Chicago, IL , USA
| | - Aparajita H Chourasia
- The Ben May Department for Cancer Research, The University of Chicago , Chicago, IL , USA ; Committee on Cancer Biology, The University of Chicago , Chicago, IL , USA
| | - Kay F Macleod
- The Ben May Department for Cancer Research, The University of Chicago , Chicago, IL , USA ; Committee on Molecular Metabolism and Nutrition, The University of Chicago , Chicago, IL , USA ; Committee on Cancer Biology, The University of Chicago , Chicago, IL , USA
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12
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13
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Abstract
Many women with high-risk pregnancies such as pregnancy-induced hypertension and preterm labor are being managed in their homes. By using tools designed to detect subtle changes in the health status of the woman and her fetus, the home healthcare nurse can have a positive impact on the treatment and outcome of the pregnancy.
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Affiliation(s)
- M P Kodadek
- George Mason University, College of Nursing and Health Science, Fairfax, Virginia 22030, USA
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14
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