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Uchikado Y, Ikeda Y, Sasaki Y, Iwabayashi M, Akasaki Y, Ohishi M. Association of Lectin-Like Oxidized Low-Density Lipoprotein Receptor-1 With Angiotensin II Type 1 Receptor Impacts Mitochondrial Quality Control, Offering Promise for the Treatment of Vascular Senescence. Front Cardiovasc Med 2021; 8:788655. [PMID: 34869701 PMCID: PMC8637926 DOI: 10.3389/fcvm.2021.788655] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 10/26/2021] [Indexed: 12/14/2022] Open
Abstract
Lectin-like oxidized low-density lipoprotein (ox-LDL) causes vascular senescence and atherosclerosis. It has been reported that ox-LDL scavenger receptor-1 (LOX-1) is associated with the angiotensin II type 1 receptor (AT1R). While mitochondria play a crucial role in the development of vascular senescence and atherosclerosis, they also undergo quality control through mitochondrial dynamics and autophagy. The aim of this study was to investigate (1) whether LOX-1 associates with AT1R, (2) if this regulates mitochondrial quality control, and (3) whether AT1R inhibition using Candesartan might ameliorate ox-LDL-induced vascular senescence. We performed in vitro and in vivo experiments using vascular smooth muscle cells (VSMCs), and C57BL/6 and apolipoprotein E-deficient (ApoE KO) mice. Administration of oxidized low-density lipoprotein (ox-LDL) to VSMCs induced mitochondrial dysfunction and cellular senescence accompanied by excessive mitochondrial fission, due to the activation of fission factor Drp1, which was derived from the activation of the Raf/MEK/ERK pathway. Administration of either Drp1 inhibitor, mdivi-1, or AT1R blocker candesartan attenuated these alterations. Electron microscopy and immunohistochemistry of the co-localization of LAMP2 with TOMM20 signal showed that AT1R inhibition also increased mitochondrial autophagy, but this was not affected by Atg7 deficiency. Conversely, AT1R inhibition increased the co-localization of LAMP2 with Rab9 signal. Moreover, AT1R inhibition-induced mitochondrial autophagy was abolished by Rab9 deficiency, suggesting that AT1R signaling modulated mitochondrial autophagy derived from Rab9-dependent alternative autophagy. Inhibition of the Raf/MEK/ERK pathway also decreased the excessive mitochondrial fission, and Rab9-dependent mitochondrial autophagy, suggesting that AT1R signaling followed the Raf/MEK/ERK axis modulated both mitochondrial dynamics and autophagy. The degree of mitochondrial dysfunction, reactive oxygen species production, vascular senescence, atherosclerosis, and the number of fragmented mitochondria accompanied by Drp1 activation were all higher in ApoE KO mice than in C57BL/6 mice. These detrimental alterations were successfully restored, and mitochondrial autophagy was upregulated with the administration of candesartan to ApoE KO mice. The association of LOX-1 with AT1R was found to play a crucial role in regulating mitochondrial quality control, as cellular/vascular senescence is induced by ox-LDL, and AT1R inhibition improves the adverse effects of ox-LDL.
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Affiliation(s)
- Yoshihiro Uchikado
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences Kagoshima University, Kagoshima, Japan
| | - Yoshiyuki Ikeda
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences Kagoshima University, Kagoshima, Japan
| | - Yuichi Sasaki
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences Kagoshima University, Kagoshima, Japan
| | - Masaaki Iwabayashi
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences Kagoshima University, Kagoshima, Japan
| | - Yuichi Akasaki
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences Kagoshima University, Kagoshima, Japan
| | - Mitsuru Ohishi
- Department of Cardiovascular Medicine and Hypertension, Graduate School of Medical and Dental Sciences Kagoshima University, Kagoshima, Japan
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102
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Collier JJ, Suomi F, Oláhová M, McWilliams TG, Taylor RW. Emerging roles of ATG7 in human health and disease. EMBO Mol Med 2021; 13:e14824. [PMID: 34725936 PMCID: PMC8649875 DOI: 10.15252/emmm.202114824] [Citation(s) in RCA: 82] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 12/12/2022] Open
Abstract
The cardinal stages of macroautophagy are driven by core autophagy-related (ATG) proteins, whose ablation largely abolishes intracellular turnover. Disrupting ATG genes is paradigmatic of studying autophagy deficiency, yet emerging data suggest that ATG proteins have extensive biological importance beyond autophagic elimination. An important example is ATG7, an essential autophagy effector enzyme that in concert with other ATG proteins, also regulates immunity, cell death and protein secretion, and independently regulates the cell cycle and apoptosis. Recently, a direct association between ATG7 dysfunction and disease was established in patients with biallelic ATG7 variants and childhood-onset neuropathology. Moreover, a prodigious body of evidence supports a role for ATG7 in protecting against complex disease states in model organisms, although how dysfunctional ATG7 contributes to manifestation of these diseases, including cancer, neurodegeneration and infection, in humans remains unclear. Here, we systematically review the biological functions of ATG7, discussing the impact of its impairment on signalling pathways and human pathology. Future studies illuminating the molecular relationship between ATG7 dysfunction and disease will expedite therapies for disorders involving ATG7 deficiency and/or impaired autophagy.
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Affiliation(s)
- Jack J Collier
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research InstituteNewcastle UniversityNewcastle upon TyneUK
- Present address:
Department of Neurology and NeurosurgeryMontreal Neurological InstituteMcGill UniversityMontrealQCCanada
| | - Fumi Suomi
- Translational Stem Cell Biology & Metabolism Program, Research Programs UnitUniversity of HelsinkiHelsinkiFinland
| | - Monika Oláhová
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research InstituteNewcastle UniversityNewcastle upon TyneUK
| | - Thomas G McWilliams
- Translational Stem Cell Biology & Metabolism Program, Research Programs UnitUniversity of HelsinkiHelsinkiFinland
- Department of AnatomyFaculty of MedicineUniversity of HelsinkiHelsinkiFinland
| | - Robert W Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research InstituteNewcastle UniversityNewcastle upon TyneUK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders of Adults and ChildrenNewcastle UniversityNewcastle upon TyneUK
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103
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Vargas-Mendoza N, Angeles-Valencia M, Morales-González Á, Madrigal-Santillán EO, Morales-Martínez M, Madrigal-Bujaidar E, Álvarez-González I, Gutiérrez-Salinas J, Esquivel-Chirino C, Chamorro-Cevallos G, Cristóbal-Luna JM, Morales-González JA. Oxidative Stress, Mitochondrial Function and Adaptation to Exercise: New Perspectives in Nutrition. Life (Basel) 2021; 11:life11111269. [PMID: 34833151 PMCID: PMC8624755 DOI: 10.3390/life11111269] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/10/2021] [Accepted: 11/13/2021] [Indexed: 02/07/2023] Open
Abstract
Cells have the ability to adapt to stressful environments as a part of their evolution. Physical exercise induces an increase of a demand for energy that must be met by mitochondria as the main (ATP) provider. However, this process leads to the increase of free radicals and the so-called reactive oxygen species (ROS), which are necessary for the maintenance of cell signaling and homeostasis. In addition, mitochondrial biogenesis is influenced by exercise in continuous crosstalk between the mitochondria and the nuclear genome. Excessive workloads may induce severe mitochondrial stress, resulting in oxidative damage. In this regard, the objective of this work was to provide a general overview of the molecular mechanisms involved in mitochondrial adaptation during exercise and to understand if some nutrients such as antioxidants may be implicated in blunt adaptation and/or an impact on the performance of exercise by different means.
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Affiliation(s)
- Nancy Vargas-Mendoza
- Laboratorio de Medicina de Conservación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Col. Casco de Santo Tomás, Del. Miguel Hidalgo, Ciudad de México 11340, Mexico; (N.V.-M.); (M.A.-V.); (E.O.M.-S.)
| | - Marcelo Angeles-Valencia
- Laboratorio de Medicina de Conservación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Col. Casco de Santo Tomás, Del. Miguel Hidalgo, Ciudad de México 11340, Mexico; (N.V.-M.); (M.A.-V.); (E.O.M.-S.)
| | - Ángel Morales-González
- Escuela Superior de Cómputo, Instituto Politécnico Nacional, Av. Juan de Dios Bátiz s/n Esquina Miguel Othón de Mendizabal, Unidad Profesional Adolfo López Mateos, Ciudad de México 07738, Mexico
- Correspondence: (Á.M.-G.); (J.A.M.-G.); Tel.: +52-55-5729-6300 (Á.M.-G. & J.A.M.-G.)
| | - Eduardo Osiris Madrigal-Santillán
- Laboratorio de Medicina de Conservación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Col. Casco de Santo Tomás, Del. Miguel Hidalgo, Ciudad de México 11340, Mexico; (N.V.-M.); (M.A.-V.); (E.O.M.-S.)
| | - Mauricio Morales-Martínez
- Licenciatura en Nutrición, Universidad Intercontinental, Insurgentes Sur 4303, Santa Úrsula Xitla, Alcaldía Tlalpan, Ciudad de México 14420, Mexico;
| | - Eduardo Madrigal-Bujaidar
- Laboratorio de Genética, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Unidad Profesional A. López Mateos, Av. Wilfrido Massieu, Col., Lindavista, Ciudad de México 07738, Mexico; (E.M.-B.); (I.Á.-G.)
| | - Isela Álvarez-González
- Laboratorio de Genética, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Unidad Profesional A. López Mateos, Av. Wilfrido Massieu, Col., Lindavista, Ciudad de México 07738, Mexico; (E.M.-B.); (I.Á.-G.)
| | - José Gutiérrez-Salinas
- Laboratorio de Bioquímica y Medicina Experimental, Centro Médico Nacional “20 de Noviembre”, ISSSTE, Ciudad de México 03229, Mexico;
| | - César Esquivel-Chirino
- Área de Básicas Médicas, División de Estudios Profesionales, Facultad de Odontología, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
| | - Germán Chamorro-Cevallos
- Laboratorio de Toxicología Preclínica, Departamento de Farmacia, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu 399, Col. Nueva Industrial Vallejo, Del. Gustavo A. Madero, Ciudad de México 07738, Mexico; (G.C.-C.); (J.M.C.-L.)
| | - José Melesio Cristóbal-Luna
- Laboratorio de Toxicología Preclínica, Departamento de Farmacia, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Av. Wilfrido Massieu 399, Col. Nueva Industrial Vallejo, Del. Gustavo A. Madero, Ciudad de México 07738, Mexico; (G.C.-C.); (J.M.C.-L.)
| | - José A. Morales-González
- Laboratorio de Medicina de Conservación, Escuela Superior de Medicina, Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón, Col. Casco de Santo Tomás, Del. Miguel Hidalgo, Ciudad de México 11340, Mexico; (N.V.-M.); (M.A.-V.); (E.O.M.-S.)
- Correspondence: (Á.M.-G.); (J.A.M.-G.); Tel.: +52-55-5729-6300 (Á.M.-G. & J.A.M.-G.)
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104
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Cunningham RP, Moore MP, Dashek RJ, Meers GM, Takahashi T, Sheldon RD, Wheeler AA, Diaz-Arias A, Ibdah JA, Parks EJ, Thyfault JP, Rector RS. Critical Role for Hepatocyte-Specific eNOS in NAFLD and NASH. Diabetes 2021; 70:2476-2491. [PMID: 34380696 PMCID: PMC8564406 DOI: 10.2337/db20-1228] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 07/30/2021] [Indexed: 11/13/2022]
Abstract
Regulation of endothelial nitric oxide synthase (eNOS) in hepatocytes may be an important target in nonalcoholic fatty liver disease (NAFLD) development and progression to nonalcoholic steatohepatitis (NASH). In this study, we show genetic deletion and viral knockdown of hepatocyte-specific eNOS exacerbated hepatic steatosis and inflammation, decreased hepatic mitochondrial fatty acid oxidation and respiration, increased mitochondrial H2O2 emission, and impaired the hepatic mitophagic (BNIP3 and LC3II) response. Conversely, overexpressing eNOS in hepatocytes in vitro and in vivo increased hepatocyte mitochondrial respiration and attenuated Western diet-induced NASH. Moreover, patients with elevated NAFLD activity score (histology score of worsening steatosis, hepatocyte ballooning, and inflammation) exhibited reduced hepatic eNOS expression, which correlated with reduced hepatic mitochondrial fatty acid oxidation and lower hepatic protein expression of mitophagy protein BNIP3. The current study reveals an important molecular role for hepatocyte-specific eNOS as a key regulator of NAFLD/NASH susceptibility and mitochondrial quality control with direct clinical correlation to patients with NASH.
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Affiliation(s)
- Rory P Cunningham
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Mary P Moore
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Ryan J Dashek
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Comparative Medicine Program, University of Missouri, Columbia, MO
| | - Grace M Meers
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
| | - Takamune Takahashi
- Division of Nephrology and Hypertension, Vanderbilt University School of Medicine, Nashville, TN
| | - Ryan D Sheldon
- Metabolic and Nutritional Programming, Center for Cancer and Cell Biology, Van Andel Institute, Grand Rapids, MI
| | | | | | - Jamal A Ibdah
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO
| | - Elizabeth J Parks
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO
| | - John P Thyfault
- Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS
- Kansas City VA Medical Center, Kansas City, MO
| | - R Scott Rector
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, MO
- Division of Gastroenterology and Hepatology, Department of Medicine, University of Missouri, Columbia, MO
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105
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Garcia DA, Powers AF, Bell TA, Guo S, Aghajan M. Antisense Oligonucleotide-Mediated Silencing of Mitochondrial Fusion and Fission Factors Modulates Mitochondrial Dynamics and Rescues Mitochondrial Dysfunction. Nucleic Acid Ther 2021; 32:51-65. [PMID: 34698563 PMCID: PMC8817704 DOI: 10.1089/nat.2021.0029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Mitochondria are highly dynamic organelles that produce ATP and maintain metabolic, catabolic, and redox homeostasis. Mitochondria owe this dynamic nature to their constant fission and fusion—processes that are regulated, in part, by fusion factors (MFN1 and MFN2) and fission factors (DRP1, FIS1, MFF, MIEF1, MIEF2) located on the outer mitochondrial membrane. While mitochondrial fusion and fission are known to influence mitochondrial morphology and function, a key question is whether rebalancing mitochondrial morphology can ameliorate mitochondrial dysfunction in the context of mitochondrial pathology. In this study, we used antisense oligonucleotides (ASOs) to systematically evaluate the effects of fusion and fission factors in vitro. Free uptake by cells of fusion or fission factor ASOs caused robust decreases in target gene expression and altered a variety of mitochondrial parameters, including mitochondrial size and respiration, which were dose dependent. In Mfn1 knockout mouse embryonic fibroblasts (MEFs) and MFN2-R94Q (Charcot-Marie-Tooth Type 2 Disease-associated mutation) MEFs, two cellular models of mitochondrial dysfunction, we found that ASO-mediated silencing of only Drp1 restored mitochondrial morphology and enhanced mitochondrial respiration. Together, these data demonstrate in vitro proof-of-concept for rebalancing mitochondrial morphology to rescue function using ASOs and suggest that ASO-mediated modulation of mitochondrial dynamics may be a viable therapeutic approach to restore mitochondrial homeostasis in diseases driven by mitochondrial dysfunction.
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Affiliation(s)
| | | | - Thomas A Bell
- Ionis Pharmaceuticals, Inc., Carlsbad, California,, USA
| | - Shuling Guo
- Ionis Pharmaceuticals, Inc., Carlsbad, California,, USA
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106
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Peng SZ, Chen XH, Chen SJ, Zhang J, Wang CY, Liu WR, Zhang D, Su Y, Zhang XK. Phase separation of Nur77 mediates celastrol-induced mitophagy by promoting the liquidity of p62/SQSTM1 condensates. Nat Commun 2021; 12:5989. [PMID: 34645818 PMCID: PMC8514450 DOI: 10.1038/s41467-021-26295-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Accepted: 09/29/2021] [Indexed: 12/12/2022] Open
Abstract
Liquid-liquid phase separation promotes the formation of membraneless condensates that mediate diverse cellular functions, including autophagy of misfolded proteins. However, how phase separation participates in autophagy of dysfunctional mitochondria (mitophagy) remains obscure. We previously discovered that nuclear receptor Nur77 (also called TR3, NGFI-B, or NR4A1) translocates from the nucleus to mitochondria to mediate celastrol-induced mitophagy through interaction with p62/SQSTM1. Here, we show that the ubiquitinated mitochondrial Nur77 forms membraneless condensates capable of sequestrating damaged mitochondria by interacting with the UBA domain of p62/SQSTM1. However, tethering clustered mitochondria to the autophagy machinery requires an additional interaction mediated by the N-terminal intrinsically disordered region (IDR) of Nur77 and the N-terminal PB1 domain of p62/SQSTM1, which confers Nur77-p62/SQSTM1 condensates with the magnitude and liquidity. Our results demonstrate how composite multivalent interaction between Nur77 and p62/SQSTM1 coordinates to sequester damaged mitochondria and to connect targeted cargo mitochondria for autophagy, providing mechanistic insight into mitophagy.
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Affiliation(s)
- Shuang-Zhou Peng
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
| | - Xiao-Hui Chen
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
| | - Si-Jie Chen
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
| | - Jie Zhang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
| | - Chuan-Ying Wang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
| | - Wei-Rong Liu
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
| | - Duo Zhang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
| | - Ying Su
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China
- NucMito Pharmaceuticals Co. Ltd., Xiamen, 361101, China
| | - Xiao-Kun Zhang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen, 361102, China.
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107
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Abstract
Mitochondria, which resemble their α-proteobacteria ancestors, are a major cellular asset, producing energy 'on the cheap' through oxidative phosphorylation. They are also a liability. Increased oxidative phosphorylation means increased oxidative stress, and damaged mitochondria incite inflammation through release of their bacteria-like macromolecules. Mitophagy (the selective macroautophagy of mitochondria) controls mitochondria quality and number to manage these risky assets. Parkin, BNIP3 and NIX were identified as being part of the first mitophagy pathways identified in mammals over a decade ago, with additional pathways, including that mediated by FUNDC1 reported more recently. Loss of Parkin or PINK1 function causes Parkinson's disease, highlighting the importance of mitophagy as a quality control mechanism in the brain. Additionally, mitophagy is induced in idiopathic Parkinson's disease and Alzheimer's disease, protects the heart and other organs against energy stress and lipotoxicity, regulates metabolism by controlling mitochondrial number in brown and beige fat, and clears mitochondria during terminal differentiation of glycolytic cells, such as red blood cells and neurons. Despite its importance in disease, mitophagy is likely dispensable under physiological conditions. This Review explores the in vivo roles of mitophagy in mammalian systems, focusing on the best studied examples - mitophagy in neurodegeneration, cardiomyopathy, metabolism, and red blood cell development - to draw out common themes.
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Affiliation(s)
- Derek P. Narendra
- Inherited Movement Disorders Unit, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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108
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Rogers MA, Hutcheson JD, Okui T, Goettsch C, Singh SA, Halu A, Schlotter F, Higashi H, Wang L, Whelan MC, Mlynarchik AK, Daugherty A, Nomura M, Aikawa M, Aikawa E. Dynamin-related protein 1 inhibition reduces hepatic PCSK9 secretion. Cardiovasc Res 2021; 117:2340-2353. [PMID: 33523181 PMCID: PMC8479802 DOI: 10.1093/cvr/cvab034] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/29/2020] [Accepted: 01/27/2021] [Indexed: 12/26/2022] Open
Abstract
AIMS Proteostasis maintains protein homeostasis and participates in regulating critical cardiometabolic disease risk factors including proprotein convertase subtilisin/kexin type 9 (PCSK9). Endoplasmic reticulum (ER) remodeling through release and incorporation of trafficking vesicles mediates protein secretion and degradation. We hypothesized that ER remodeling that drives mitochondrial fission participates in cardiometabolic proteostasis. METHODS AND RESULTS We used in vitro and in vivo hepatocyte inhibition of a protein involved in mitochondrial fission, dynamin-related protein 1 (DRP1). Here, we show that DRP1 promotes remodeling of select ER microdomains by tethering vesicles at ER. A DRP1 inhibitor, mitochondrial division inhibitor 1 (mdivi-1) reduced ER localization of a DRP1 receptor, mitochondrial fission factor, suppressing ER remodeling-driven mitochondrial fission, autophagy, and increased mitochondrial calcium buffering and PCSK9 proteasomal degradation. DRP1 inhibition by CRISPR/Cas9 deletion or mdivi-1 alone or in combination with statin incubation in human hepatocytes and hepatocyte-specific Drp1-deficiency in mice reduced PCSK9 secretion (-78.5%). In HepG2 cells, mdivi-1 increased low-density lipoprotein receptor via c-Jun transcription and reduced PCSK9 mRNA levels via suppressed sterol regulatory binding protein-1c. Additionally, mdivi-1 reduced macrophage burden, oxidative stress, and advanced calcified atherosclerotic plaque in aortic roots of diabetic Apoe-deficient mice and inflammatory cytokine production in human macrophages. CONCLUSIONS We propose a novel tethering function of DRP1 beyond its established fission function, with DRP1-mediated ER remodeling likely contributing to ER constriction of mitochondria that drives mitochondrial fission. We report that DRP1-driven remodeling of select ER micro-domains may critically regulate hepatic proteostasis and identify mdivi-1 as a novel small molecule PCSK9 inhibitor.
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Affiliation(s)
- Maximillian A Rogers
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Joshua D Hutcheson
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Takehito Okui
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Claudia Goettsch
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Sasha A Singh
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Arda Halu
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Florian Schlotter
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hideyuki Higashi
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lixiang Wang
- Department of Medical Biochemistry, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Mary C Whelan
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew K Mlynarchik
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Alan Daugherty
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY 40536, USA
| | - Masatoshi Nomura
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Kurume 830-0011, Japan
| | - Masanori Aikawa
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Elena Aikawa
- Center for Interdisciplinary Cardiovascular Sciences, Cardiovascular Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Department of Human Pathology, Sechenov First Moscow State Medical University, Moscow 119992, Russia
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109
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Zhou M, Yu Y, Luo X, Wang J, Lan X, Liu P, Feng Y, Jian W. Myocardial Ischemia-Reperfusion Injury: Therapeutics from a Mitochondria-Centric Perspective. Cardiology 2021; 146:781-792. [PMID: 34547747 DOI: 10.1159/000518879] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 07/01/2021] [Indexed: 11/19/2022]
Abstract
Coronary arterial disease is the most common cardiovascular disease. Myocardial ischemia-reperfusion injury caused by the initial interruption of organ blood flow and subsequent restoration of organ blood flow is an important clinical problem with various cardiac reperfusion strategies after acute myocardial infarction. Even though blood flow recovery is necessary for oxygen and nutrient supply, reperfusion causes pathological sequelae that lead to the aggravation of ischemic injury. At present, although it is known that injury will occur after reperfusion, clinical treatment always focuses on immediate recanalization. Mitochondrial fusion, fission, biogenesis, autophagy, and their intricate interaction constitute an effective mitochondrial quality control system. The mitochondrial quality control system plays an important role in maintaining cell homeostasis and cell survival. The removal of damaged, aging, and dysfunctional mitochondria is mediated by mitochondrial autophagy. With the help of appropriate changes in mitochondrial dynamics, new mitochondria are produced through mitochondrial biogenesis to meet the energy needs of cells. Mitochondrial dysfunction and the resulting oxidative stress have been associated with the pathogenesis of ischemia/reperfusion (I/R) injury, which play a crucial role in the pathophysiological process of myocardial injury. This review aimed at elucidating the mitochondrial quality control system and establishing the possibility of using mitochondria as a potential therapeutic target in the treatment of I/R injuries.
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Affiliation(s)
- Manli Zhou
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China,
| | - Yunfeng Yu
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China
| | - Xiaoxin Luo
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China
| | - Jianzhang Wang
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China
| | - Xiaodong Lan
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China
| | - Pei Liu
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China
| | - Yu Feng
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China
| | - Weixiong Jian
- College of Traditional Chinese Medicine, Hunan University of Traditional Chinese Medicine, Changsha, China.,National Key Discipline of Traditional Chinese Medicine Diagnostics, Hunan Provincial Key Laboratory, Hunan University of Chinese Medicine, Changsha, China
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110
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Kumar S, Duan Q, Wu R, Harris EN, Su Q. Pathophysiological communication between hepatocytes and non-parenchymal cells in liver injury from NAFLD to liver fibrosis. Adv Drug Deliv Rev 2021; 176:113869. [PMID: 34280515 DOI: 10.1016/j.addr.2021.113869] [Citation(s) in RCA: 129] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/16/2021] [Accepted: 07/11/2021] [Indexed: 02/07/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disease that encompasses a spectrum of pathological conditions, ranging from simple steatosis (NAFL), nonalcoholic steatohepatitis (NASH), fibrosis/cirrhosis which can further progress to hepatocellular carcinoma and liver failure. The progression of NAFL to NASH and liver fibrosis is closely associated with a series of liver injury resulting from lipotoxicity, oxidative stress, redox imbalance (excessive nitric oxide), ER stress, inflammation and apoptosis that occur sequentially in different liver cells which ultimately leads to the activation of liver regeneration and fibrogenesis, augmenting collagen and extracellular matrix deposition and promoting liver fibrosis and cirrhosis. Type 2 diabetes is a significant risk factor in NAFLD development by accelerating liver damage. Here, we overview recent findings from human study and animal models on the pathophysiological communication among hepatocytes (HCs), Kupffer cells (KCs), hepatic stellate cells (HSCs) and liver sinusoidal endothelial cells (LSECs) during the disease development. The mechanisms of crucial signaling pathways, including Toll-like receptor, TGFβ and hedgehog mediated hepatic injury are also discussed. We further highlight the potentials of precisely targeting hepatic individual cell-type using nanotechnology as therapeutic strategy for the treatment of NASH and liver fibrosis.
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111
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Takeichi Y, Miyazawa T, Sakamoto S, Hanada Y, Wang L, Gotoh K, Uchida K, Katsuhara S, Sakamoto R, Ishihara T, Masuda K, Ishihara N, Nomura M, Ogawa Y. Non-alcoholic fatty liver disease in mice with hepatocyte-specific deletion of mitochondrial fission factor. Diabetologia 2021; 64:2092-2107. [PMID: 34052855 PMCID: PMC8382662 DOI: 10.1007/s00125-021-05488-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 03/22/2021] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS Mitochondria are highly dynamic organelles continuously undergoing fission and fusion, referred to as mitochondrial dynamics, to adapt to nutritional demands. Evidence suggests that impaired mitochondrial dynamics leads to metabolic abnormalities such as non-alcoholic steatohepatitis (NASH) phenotypes. However, how mitochondrial dynamics are involved in the development of NASH is poorly understood. This study aimed to elucidate the role of mitochondrial fission factor (MFF) in the development of NASH. METHODS We created mice with hepatocyte-specific deletion of MFF (MffLiKO). MffLiKO mice fed normal chow diet (NCD) or high-fat diet (HFD) were evaluated for metabolic variables and their livers were examined by histological analysis. To elucidate the mechanism of development of NASH, we examined the expression of genes related to endoplasmic reticulum (ER) stress and lipid metabolism, and the secretion of triacylglycerol (TG) using the liver and primary hepatocytes isolated from MffLiKO and control mice. RESULTS MffLiKO mice showed aberrant mitochondrial morphologies with no obvious NASH phenotypes during NCD, while they developed full-blown NASH phenotypes in response to HFD. Expression of genes related to ER stress was markedly upregulated in the liver from MffLiKO mice. In addition, expression of genes related to hepatic TG secretion was downregulated, with reduced hepatic TG secretion in MffLiKO mice in vivo and in primary cultures of MFF-deficient hepatocytes in vitro. Furthermore, thapsigargin-induced ER stress suppressed TG secretion in primary hepatocytes isolated from control mice. CONCLUSIONS/INTERPRETATION We demonstrated that ablation of MFF in liver provoked ER stress and reduced hepatic TG secretion in vivo and in vitro. Moreover, MffLiKO mice were more susceptible to HFD-induced NASH phenotype than control mice, partly because of ER stress-induced apoptosis of hepatocytes and suppression of TG secretion from hepatocytes. This study provides evidence for the role of mitochondrial fission in the development of NASH.
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Affiliation(s)
- Yukina Takeichi
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takashi Miyazawa
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
| | - Shohei Sakamoto
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuki Hanada
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Lixiang Wang
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuhito Gotoh
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Keiichiro Uchida
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shunsuke Katsuhara
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Ryuichi Sakamoto
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takaya Ishihara
- Department of Protein Biochemistry, Institute of Life Science, Kurume University, Fukuoka, Japan
- Department of Biological Science, Graduate School of Science, Osaka University, Osaka, Japan
| | - Keiji Masuda
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, Japan
| | - Naotada Ishihara
- Department of Protein Biochemistry, Institute of Life Science, Kurume University, Fukuoka, Japan
- Department of Biological Science, Graduate School of Science, Osaka University, Osaka, Japan
| | - Masatoshi Nomura
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Kurume University School of Medicine, Fukuoka, Japan
| | - Yoshihiro Ogawa
- Department of Medicine and Bioregulatory Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
- Japan Agency for Medical Research and Development, CREST, Tokyo, Japan.
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112
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Yamano K, Kojima W. Molecular functions of autophagy adaptors upon ubiquitin-driven mitophagy. Biochim Biophys Acta Gen Subj 2021; 1865:129972. [PMID: 34332032 DOI: 10.1016/j.bbagen.2021.129972] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/16/2021] [Accepted: 07/21/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Perturbations in organellar health can lead to an accumulation of unwanted and/or damaged organelles that are toxic to the cell and which can contribute to the onset of neurodegenerative diseases such as Parkinson's disease. Mitochondrial health is particularly critical given the indispensable role the organelle has not only in adenosine triphosphate production but also other metabolic processes. Byproducts of oxidative respiration, such as reactive oxygen species, however, can negatively impact mitochondrial fitness. Consequently, selective degradation of damaged mitochondria, which occurs via a specific autophagic process termed mitophagy, is essential for normal cell maintenance. SCOPE OF REVIEW Recent accumulating evidence has shown that autophagy adaptors (also referred to as autophagy receptors) play critical roles in connecting ubiquitinated mitochondria with the autophagic machinery of the autophagy-lysosome pathway that is required for degradation. In this review, we focus on our current understanding of the autophagy adaptor mechanisms underlying PINK1/Parkin-driven mitophagy. MAJOR CONCLUSIONS Although autophagy adaptors are canonically defined as proteins that possess ubiquitin-binding domains and ATG8s-binding motifs, the recent identification of novel binding partners has contributed to the development of a more sophisticated model for how autophagy adaptors contribute to the molecular hub that organizes autophagic cargo-degradation. GENERAL SIGNIFICANCE Although mitophagy is recognized as one of the selective autophagy pathways that removes dysfunctional mitochondria, a more nuanced understanding of the interactions connecting autophagy adaptors and their associated proteins is needed to gain deeper insights into the fundamental biological processes underlying human diseases, including neurodegenerative disorders. This review is part of a Special Issue entitled Mitophagy.
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Affiliation(s)
- Koji Yamano
- Ubiquitin Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan.
| | - Waka Kojima
- Ubiquitin Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya-ku, Tokyo 156-8506, Japan
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113
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López-Doménech G, Howden JH, Covill-Cooke C, Morfill C, Patel JV, Bürli R, Crowther D, Birsa N, Brandon NJ, Kittler JT. Loss of neuronal Miro1 disrupts mitophagy and induces hyperactivation of the integrated stress response. EMBO J 2021; 40:e100715. [PMID: 34152608 PMCID: PMC8280823 DOI: 10.15252/embj.2018100715] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 04/23/2021] [Accepted: 05/03/2021] [Indexed: 12/31/2022] Open
Abstract
Clearance of mitochondria following damage is critical for neuronal homeostasis. Here, we investigate the role of Miro proteins in mitochondrial turnover by the PINK1/Parkin mitochondrial quality control system in vitro and in vivo. We find that upon mitochondrial damage, Miro is promiscuously ubiquitinated on multiple lysine residues. Genetic deletion of Miro or block of Miro1 ubiquitination and subsequent degradation lead to delayed translocation of the E3 ubiquitin ligase Parkin onto damaged mitochondria and reduced mitochondrial clearance in both fibroblasts and cultured neurons. Disrupted mitophagy in vivo, upon post-natal knockout of Miro1 in hippocampus and cortex, leads to a dramatic increase in mitofusin levels, the appearance of enlarged and hyperfused mitochondria and hyperactivation of the integrated stress response (ISR). Altogether, our results provide new insights into the central role of Miro1 in the regulation of mitochondrial homeostasis and further implicate Miro1 dysfunction in the pathogenesis of human neurodegenerative disease.
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Affiliation(s)
| | - Jack H Howden
- Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | | | - Corinne Morfill
- Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Jigna V Patel
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Roland Bürli
- Neuroscience, IMED Biotech Unit, AstraZeneca, Cambridge, UK
| | | | - Nicol Birsa
- UCL Institute of Neurology, Queen Square, London, UK
| | | | - Josef T Kittler
- Neuroscience, Physiology and Pharmacology, University College London, London, UK
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114
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Liu D, Sun Z, Ye T, Li J, Zeng B, Zhao Q, Wang J, Xing HR. The mitochondrial fission factor FIS1 promotes stemness of human lung cancer stem cells via mitophagy. FEBS Open Bio 2021; 11:1997-2007. [PMID: 34051059 PMCID: PMC8406485 DOI: 10.1002/2211-5463.13207] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/11/2021] [Accepted: 05/26/2021] [Indexed: 12/14/2022] Open
Abstract
Mitophagy, a form of autophagy, plays a role in cancer development, progression and recurrence. Cancer stem cells (CSCs) also play a key role in these processes, although it not known whether mitophagy can regulate the stemness of CSCs. Here, we employed the A549-SD human non-small cell lung adenocarcinoma CSC model that we have developed and characterized to investigate the effect of mitophagy on the stemness of CSCs. We observed a positive relationship between mitophagic activity and the stemness of lung CSCs. At the mechanistic level, our results suggest that augmentation of mitophagy in lung CSCs can be induced by FIS1 through mitochondrial fission. In addition, we assessed the clinical relevance of FIS1 in lung adenocarcinoma using The Cancer Genome Atlas database. An elevation in FIS1, when observed together with other prognostic markers for lung cancer progression, was found to correlate with shorter overall survival.
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Affiliation(s)
- Doudou Liu
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founded by Chongqing and the Ministry of Science and Technology, School of Biomedical Engineering, Chongqing Medical University, China
| | - Zhiwei Sun
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founded by Chongqing and the Ministry of Science and Technology, School of Biomedical Engineering, Chongqing Medical University, China
| | - Ting Ye
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founded by Chongqing and the Ministry of Science and Technology, School of Biomedical Engineering, Chongqing Medical University, China
| | - Jingyuan Li
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founded by Chongqing and the Ministry of Science and Technology, School of Biomedical Engineering, Chongqing Medical University, China
| | - Bin Zeng
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founded by Chongqing and the Ministry of Science and Technology, School of Biomedical Engineering, Chongqing Medical University, China
| | - Qiting Zhao
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founded by Chongqing and the Ministry of Science and Technology, School of Biomedical Engineering, Chongqing Medical University, China
| | - Jianyu Wang
- Institute of Life Sciences, Chongqing Medical University, China
| | - Hongmei Rosie Xing
- State Key Laboratory of Ultrasound Engineering in Medicine Co-Founded by Chongqing and the Ministry of Science and Technology, School of Biomedical Engineering, Chongqing Medical University, China
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Cretin E, Lopes P, Vimont E, Tatsuta T, Langer T, Gazi A, Sachse M, Yu‐Wai‐Man P, Reynier P, Wai T. High-throughput screening identifies suppressors of mitochondrial fragmentation in OPA1 fibroblasts. EMBO Mol Med 2021; 13:e13579. [PMID: 34014035 PMCID: PMC8185549 DOI: 10.15252/emmm.202013579] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 03/29/2021] [Accepted: 04/01/2021] [Indexed: 12/22/2022] Open
Abstract
Mutations in OPA1 cause autosomal dominant optic atrophy (DOA) as well as DOA+, a phenotype characterized by more severe neurological deficits. OPA1 deficiency causes mitochondrial fragmentation and also disrupts cristae, respiration, mitochondrial DNA (mtDNA) maintenance, and cell viability. It has not yet been established whether phenotypic severity can be modulated by genetic modifiers of OPA1. We screened the entire known mitochondrial proteome (1,531 genes) to identify genes that control mitochondrial morphology using a first-in-kind imaging pipeline. We identified 145 known and novel candidate genes whose depletion promoted elongation or fragmentation of the mitochondrial network in control fibroblasts and 91 in DOA+ patient fibroblasts that prevented mitochondrial fragmentation, including phosphatidyl glycerophosphate synthase (PGS1). PGS1 depletion reduces CL content in mitochondria and rebalances mitochondrial dynamics in OPA1-deficient fibroblasts by inhibiting mitochondrial fission, which improves defective respiration, but does not rescue mtDNA depletion, cristae dysmorphology, or apoptotic sensitivity. Our data reveal that the multifaceted roles of OPA1 in mitochondria can be functionally uncoupled by modulating mitochondrial lipid metabolism, providing novel insights into the cellular relevance of mitochondrial fragmentation.
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Affiliation(s)
- Emma Cretin
- Mitochondrial Biology GroupInstitut PasteurCNRS UMR 3691ParisFrance
- Université de ParisParisFrance
| | - Priscilla Lopes
- Mitochondrial Biology GroupInstitut PasteurCNRS UMR 3691ParisFrance
| | - Elodie Vimont
- Mitochondrial Biology GroupInstitut PasteurCNRS UMR 3691ParisFrance
| | | | - Thomas Langer
- Max‐Planck‐Institute for Biology of AgeingCologneGermany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Anastasia Gazi
- UTechS Ultrastructural Bio ImagingInstitut PasteurParisFrance
| | - Martin Sachse
- UTechS Ultrastructural Bio ImagingInstitut PasteurParisFrance
| | - Patrick Yu‐Wai‐Man
- Cambridge Centre for Brain Repair and MRC Mitochondrial Biology UnitDepartment of Clinical NeurosciencesUniversity of CambridgeCambridgeUK
- Cambridge Eye UnitAddenbrooke's HospitalCambridge University HospitalsCambridgeUK
- Moorfields Eye HospitalLondonUK
- UCL Institute of OphthalmologyUniversity College LondonLondonUK
| | - Pascal Reynier
- Laboratoire de Biochimie et biologie moléculaireCentre Hospitalier UniversitaireAngersFrance
- Unité Mixte de Recherche MITOVASCCNRS 6015INSERM U1083Université d'AngersAngersFrance
| | - Timothy Wai
- Mitochondrial Biology GroupInstitut PasteurCNRS UMR 3691ParisFrance
- Université de ParisParisFrance
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DHA Protects Hepatocytes from Oxidative Injury through GPR120/ERK-Mediated Mitophagy. Int J Mol Sci 2021; 22:ijms22115675. [PMID: 34073582 PMCID: PMC8198367 DOI: 10.3390/ijms22115675] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 05/22/2021] [Accepted: 05/24/2021] [Indexed: 11/17/2022] Open
Abstract
Oxidative stress occurs in a variety of clinical liver diseases and causes cellular damage and mitochondrial dysfunction. The clearance of damaged mitochondria by mitophagy may facilitate mitochondrial biogenesis and enhance cell survival. Although the supplementation of docosahexaenoic acid (DHA) has been recognized to relieve the symptoms of various liver diseases, the antioxidant effect of DHA in liver disease is still unclear. The purpose of our research was to investigate the antioxidant effect of DHA in the liver and the possible role of mitophagy in this. In vitro, H2O2-induced injury was caused in AML12 cells. The results showed that DHA repressed the level of reactive oxygen species (ROS) induced by H2O2 and stimulated the cellular antioxidation response. Most notably, DHA restored oxidative stress-impaired autophagic flux and promoted protective autophagy. In addition, PINK/Parkin-mediated mitophagy was activated by DHA in AML12 cells and alleviated mitochondrial dysfunction. The ERK1/2 signaling pathway was inhibited during oxidative stress but reactivated by DHA treatment. It was proven that the expression of ERK1/2 was involved in the regulation of mitophagy by the ERK1/2 inhibitor. We further proved these results in vivo. DHA effectively alleviated the liver oxidative damage caused by CCl4 and enhanced antioxidation capacity; intriguingly, autophagy was also activated. In summary, our data demonstrated that DHA protected hepatocytes from oxidative damage through GPR120/ERK-mediated mitophagy.
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117
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Mitochondrial Dynamics and Liver Cancer. Cancers (Basel) 2021; 13:cancers13112571. [PMID: 34073868 PMCID: PMC8197222 DOI: 10.3390/cancers13112571] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 05/15/2021] [Accepted: 05/19/2021] [Indexed: 12/24/2022] Open
Abstract
Simple Summary Hepatocellular carcinoma is a leading cause of cancer-related death worldwide. Major risk factors in liver cancer development include chronic hepatitis B or C virus, autoimmune hepatitis, diabetes mellitus, alcohol abuse, and several metabolic diseases, among others. Standard therapy shows low efficacy, and there is an urgent need for novel therapies. Recent data permit to propose that proteins that control mitochondrial morphology through changes in mitochondrial fusion or mitochondrial fission, confer susceptibility or resistance to the development of liver cancer in mouse models. Here, we review the data that suggest mitochondrial dynamics to be involved in the development of liver tumors. Abstract Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer. Due to its rising incidence and limited therapeutic options, HCC has become a leading cause of cancer-related death worldwide, accounting for 85% of all deaths due to primary liver cancers. Standard therapy for advanced-stage HCC is based on anti-angiogenic drugs such as sorafenib and, more recently, lenvatinib and regorafenib as a second line of treatment. The identification of novel therapeutic strategies is urgently required. Mitochondrial dynamics describes a group of processes that includes the movement of mitochondria along the cytoskeleton, the regulation of mitochondrial morphology and distribution, and connectivity mediated by tethering and fusion/fission events. In recent years, mitochondrial dynamic processes have emerged as key processes in the maintenance of liver mitochondrial homeostasis. In addition, some data are accumulating on the role played by mitochondrial dynamics during cancer development, and specifically on how such dynamics act directly on tumor cells or indirectly on cells responsible for tumor aggression and defense. Here, we review the data that suggest mitochondrial dynamics to be involved in the development of liver tumors.
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118
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Mitophagy and Oxidative Stress: The Role of Aging. Antioxidants (Basel) 2021; 10:antiox10050794. [PMID: 34067882 PMCID: PMC8156559 DOI: 10.3390/antiox10050794] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 05/12/2021] [Accepted: 05/15/2021] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial dysfunction is a hallmark of aging. Dysfunctional mitochondria are recognized and degraded by a selective type of macroautophagy, named mitophagy. One of the main factors contributing to aging is oxidative stress, and one of the early responses to excessive reactive oxygen species (ROS) production is the induction of mitophagy to remove damaged mitochondria. However, mitochondrial damage caused at least in part by chronic oxidative stress can accumulate, and autophagic and mitophagic pathways can become overwhelmed. The imbalance of the delicate equilibrium among mitophagy, ROS production and mitochondrial damage can start, drive, or accelerate the aging process, either in physiological aging, or in pathological age-related conditions, such as Alzheimer’s and Parkinson’s diseases. It remains to be determined which is the prime mover of this imbalance, i.e., whether it is the mitochondrial damage caused by ROS that initiates the dysregulation of mitophagy, thus activating a vicious circle that leads to the reduced ability to remove damaged mitochondria, or an alteration in the regulation of mitophagy leading to the excessive production of ROS by damaged mitochondria.
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119
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Song MY, Lee DY, Chun KS, Kim EH. The Role of NRF2/KEAP1 Signaling Pathway in Cancer Metabolism. Int J Mol Sci 2021; 22:4376. [PMID: 33922165 PMCID: PMC8122702 DOI: 10.3390/ijms22094376] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 04/14/2021] [Accepted: 04/20/2021] [Indexed: 12/17/2022] Open
Abstract
The nuclear factor-erythroid 2 p45-related factor 2 (NRF2, also called Nfe2l2) and its cytoplasmic repressor, Kelch-like ECH-associated protein 1 (KEAP1), are major regulators of redox homeostasis controlling a multiple of genes for detoxification and cytoprotective enzymes. The NRF2/KEAP1 pathway is a fundamental signaling cascade responsible for the resistance of metabolic, oxidative stress, inflammation, and anticancer effects. Interestingly, a recent accumulation of evidence has indicated that NRF2 exhibits an aberrant activation in cancer. Evidence has shown that the NRF2/KEAP1 signaling pathway is associated with the proliferation of cancer cells and tumerigenesis through metabolic reprogramming. In this review, we provide an overview of the regulatory molecular mechanism of the NRF2/KEAP1 pathway against metabolic reprogramming in cancer, suggesting that the regulation of NRF2/KEAP1 axis might approach as a novel therapeutic strategy for cancers.
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Affiliation(s)
- Moon-Young Song
- College of Pharmacy and Institute of Pharmaceutical Sciences, CHA University, Seongnam 13488, Korea; (M.-Y.S.); (D.-Y.L.)
| | - Da-Young Lee
- College of Pharmacy and Institute of Pharmaceutical Sciences, CHA University, Seongnam 13488, Korea; (M.-Y.S.); (D.-Y.L.)
| | - Kyung-Soo Chun
- College of Pharmacy, Keimyung University, Daegu 42601, Korea
| | - Eun-Hee Kim
- College of Pharmacy and Institute of Pharmaceutical Sciences, CHA University, Seongnam 13488, Korea; (M.-Y.S.); (D.-Y.L.)
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120
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Longo M, Paolini E, Meroni M, Dongiovanni P. Remodeling of Mitochondrial Plasticity: The Key Switch from NAFLD/NASH to HCC. Int J Mol Sci 2021; 22:4173. [PMID: 33920670 PMCID: PMC8073183 DOI: 10.3390/ijms22084173] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 02/06/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and the third-leading cause of cancer-related mortality. Currently, the global burden of nonalcoholic fatty liver disease (NAFLD) has dramatically overcome both viral and alcohol hepatitis, thus becoming the main cause of HCC incidence. NAFLD pathogenesis is severely influenced by lifestyle and genetic predisposition. Mitochondria are highly dynamic organelles that may adapt in response to environment, genetics and epigenetics in the liver ("mitochondrial plasticity"). Mounting evidence highlights that mitochondrial dysfunction due to loss of mitochondrial flexibility may arise before overt NAFLD, and from the early stages of liver injury. Mitochondrial failure promotes not only hepatocellular damage, but also release signals (mito-DAMPs), which trigger inflammation and fibrosis, generating an adverse microenvironment in which several hepatocytes select anti-apoptotic programs and mutations that may allow survival and proliferation. Furthermore, one of the key events in malignant hepatocytes is represented by the remodeling of glucidic-lipidic metabolism combined with the reprogramming of mitochondrial functions, optimized to deal with energy demand. In sum, this review will discuss how mitochondrial defects may be translated into causative explanations of NAFLD-driven HCC, emphasizing future directions for research and for the development of potential preventive or curative strategies.
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Affiliation(s)
- Miriam Longo
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Pad. Granelli, Via F Sforza 35, 20122 Milan, Italy; (M.L.); (E.P.); (M.M.)
- Department of Clinical Sciences and Community Health, Università degli Studi di Milano, Via Francesco Sforza 35, 20122 Milano, Italy
| | - Erika Paolini
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Pad. Granelli, Via F Sforza 35, 20122 Milan, Italy; (M.L.); (E.P.); (M.M.)
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Balzaretti 9, 20133 Milano, Italy
| | - Marica Meroni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Pad. Granelli, Via F Sforza 35, 20122 Milan, Italy; (M.L.); (E.P.); (M.M.)
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Pad. Granelli, Via F Sforza 35, 20122 Milan, Italy; (M.L.); (E.P.); (M.M.)
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121
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Ramos VDM, Kowaltowski AJ, Kakimoto PA. Autophagy in Hepatic Steatosis: A Structured Review. Front Cell Dev Biol 2021; 9:657389. [PMID: 33937257 PMCID: PMC8081956 DOI: 10.3389/fcell.2021.657389] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/16/2021] [Indexed: 01/18/2023] Open
Abstract
Steatosis is the accumulation of neutral lipids in the cytoplasm. In the liver, it is associated with overeating and a sedentary lifestyle, but may also be a result of xenobiotic toxicity and genetics. Non-alcoholic fatty liver disease (NAFLD) defines an array of liver conditions varying from simple steatosis to inflammation and fibrosis. Over the last years, autophagic processes have been shown to be directly associated with the development and progression of these conditions. However, the precise role of autophagy in steatosis development is still unclear. Specifically, autophagy is necessary for the regulation of basic metabolism in hepatocytes, such as glycogenolysis and gluconeogenesis, response to insulin and glucagon signaling, and cellular responses to free amino acid contents. Also, genetic knockout models for autophagy-related proteins suggest a critical relationship between autophagy and hepatic lipid metabolism, but some results are still ambiguous. While autophagy may seem necessary to support lipid oxidation in some contexts, other evidence suggests that autophagic activity can lead to lipid accumulation instead. This structured literature review aims to critically discuss, compare, and organize results over the last 10 years regarding rodent steatosis models that measured several autophagy markers, with genetic and pharmacological interventions that may help elucidate the molecular mechanisms involved.
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Affiliation(s)
| | | | - Pamela A. Kakimoto
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil
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122
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Oshima Y, Cartier E, Boyman L, Verhoeven N, Polster BM, Huang W, Kane M, Lederer WJ, Karbowski M. Parkin-independent mitophagy via Drp1-mediated outer membrane severing and inner membrane ubiquitination. J Cell Biol 2021; 220:211984. [PMID: 33851959 PMCID: PMC8050842 DOI: 10.1083/jcb.202006043] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 02/02/2021] [Accepted: 03/15/2021] [Indexed: 02/07/2023] Open
Abstract
Here, we report that acute reduction in mitochondrial translation fidelity (MTF) causes ubiquitination of the inner mitochondrial membrane (IMM) proteins, including TRAP1 and CPOX, which occurs selectively in mitochondria with a severed outer mitochondrial membrane (OMM). Ubiquitinated IMM recruits the autophagy machinery. Inhibiting autophagy leads to increased accumulation of mitochondria with severed OMM and ubiquitinated IMM. This process occurs downstream of the accumulation of cytochrome c/CPOX in a subset of mitochondria heterogeneously distributed throughout the cell (“mosaic distribution”). Formation of mosaic mitochondria, OMM severing, and IMM ubiquitination require active mitochondrial translation and mitochondrial fission, but not the proapoptotic proteins Bax and Bak. In contrast, in Parkin-overexpressing cells, MTF reduction does not lead to the severing of the OMM or IMM ubiquitination, but it does induce Drp1-independent ubiquitination of the OMM. Furthermore, high–cytochrome c/CPOX mitochondria are preferentially targeted by Parkin, indicating that in the context of reduced MTF, they are mitophagy intermediates regardless of Parkin expression. In sum, Parkin-deficient cells adapt to mitochondrial proteotoxicity through a Drp1-mediated mechanism that involves the severing of the OMM and autophagy targeting ubiquitinated IMM proteins.
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Affiliation(s)
- Yumiko Oshima
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
| | - Etienne Cartier
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
| | - Liron Boyman
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD
| | - Nicolas Verhoeven
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
| | - Brian M Polster
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD
| | - Maureen Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD
| | - W Jonathan Lederer
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD
| | - Mariusz Karbowski
- Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD.,Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
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123
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Doblado L, Lueck C, Rey C, Samhan-Arias AK, Prieto I, Stacchiotti A, Monsalve M. Mitophagy in Human Diseases. Int J Mol Sci 2021; 22:ijms22083903. [PMID: 33167334 PMCID: PMC8069949 DOI: 10.3390/ijms22083903] [Citation(s) in RCA: 101] [Impact Index Per Article: 33.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/23/2021] [Accepted: 03/26/2021] [Indexed: 02/06/2023] Open
Abstract
Mitophagy is a selective autophagic process, essential for cellular homeostasis, that eliminates dysfunctional mitochondria. Activated by inner membrane depolarization, it plays an important role during development and is fundamental in highly differentiated post-mitotic cells that are highly dependent on aerobic metabolism, such as neurons, muscle cells, and hepatocytes. Both defective and excessive mitophagy have been proposed to contribute to age-related neurodegenerative diseases, such as Parkinson’s and Alzheimer’s diseases, metabolic diseases, vascular complications of diabetes, myocardial injury, muscle dystrophy, and liver disease, among others. Pharmacological or dietary interventions that restore mitophagy homeostasis and facilitate the elimination of irreversibly damaged mitochondria, thus, could serve as potential therapies in several chronic diseases. However, despite extraordinary advances in this field, mainly derived from in vitro and preclinical animal models, human applications based on the regulation of mitochondrial quality in patients have not yet been approved. In this review, we summarize the key selective mitochondrial autophagy pathways and their role in prevalent chronic human diseases and highlight the potential use of specific interventions.
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Affiliation(s)
- Laura Doblado
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
| | - Claudia Lueck
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
| | - Claudia Rey
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
| | - Alejandro K. Samhan-Arias
- Department of Biochemistry, Universidad Autónoma de Madrid e Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain;
| | - Ignacio Prieto
- Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, Isaac Peral 42, 28015 Madrid, Spain;
| | - Alessandra Stacchiotti
- Department of Biomedical Sciences for Health, Universita’ Degli Studi di Milano, Via Mangiagalli 31, 20133 Milan, Italy
- U.O. Laboratorio di Morfologia Umana Applicata, IRCCS Policlinico San Donato, San Donato Milanese, 20097 Milan, Italy
- Correspondence: (A.S.); (M.M.)
| | - Maria Monsalve
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-UAM), Arturo Duperier 4, 28029 Madrid, Spain; (L.D.); (C.L.); (C.R.)
- Correspondence: (A.S.); (M.M.)
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124
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Longo M, Meroni M, Paolini E, Macchi C, Dongiovanni P. Mitochondrial dynamics and nonalcoholic fatty liver disease (NAFLD): new perspectives for a fairy-tale ending? Metabolism 2021; 117:154708. [PMID: 33444607 DOI: 10.1016/j.metabol.2021.154708] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/12/2022]
Abstract
Nonalcoholic fatty liver disease (NAFLD) includes a broad spectrum of liver dysfunctions and it is predicted to become the primary cause of liver failure and hepatocellular carcinoma. Mitochondria are highly dynamic organelles involved in multiple metabolic/bioenergetic pathways in the liver. Emerging evidence outlined that hepatic mitochondria adapt in number and functionality in response to external cues, as high caloric intake and obesity, by modulating mitochondrial biogenesis, and maladaptive mitochondrial response has been described from the early stages of NAFLD. Indeed, mitochondrial plasticity is lost in progressive NAFLD and these organelles may assume an aberrant phenotype to drive or contribute to hepatocarcinogenesis. Severe alimentary regimen and physical exercise represent the cornerstone for NAFLD care, although the low patients' compliance is urging towards the discovery of novel pharmacological treatments. Mitochondrial-targeted drugs aimed to recover mitochondrial lifecycle and to modulate oxidative stress are becoming attractive molecules to be potentially introduced for NAFLD management. Although the path guiding the switch from bench to bedside remains tortuous, the study of mitochondrial dynamics is providing intriguing perspectives for future NAFLD healthcare.
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Affiliation(s)
- Miriam Longo
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy; Department of Clinical Sciences and Community Health, Università degli Studi di Milano, 20122 Milano, Italy
| | - Marica Meroni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy; Department of Pathophysiology and Transplantation, Università degli Studi di Milano, 20122 Milano, Italy
| | - Erika Paolini
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy; Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy
| | - Chiara Macchi
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, 20133 Milano, Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic Diseases, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, Pad. Granelli, via F Sforza 35, 20122 Milan, Italy.
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125
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Abstract
Cells use mitophagy to remove dysfunctional or excess mitochondria, frequently in response to imposed stresses, such as hypoxia and nutrient deprivation. Mitochondrial cargo receptors (MCR) induced by these stresses target mitochondria to autophagosomes through interaction with members of the LC3/GABARAP family. There are a growing number of these MCRs, including BNIP3, BNIP3L, FUNDC1, Bcl2-L-13, FKBP8, Prohibitin-2, and others, in addition to mitochondrial protein targets of PINK1/Parkin phospho-ubiquitination. There is also an emerging link between mitochondrial lipid signaling and mitophagy where ceramide, sphingosine-1-phosphate, and cardiolipin have all been shown to promote mitophagy. Here, we review the upstream signaling mechanisms that regulate mitophagy, including components of the mitochondrial fission machinery, AMPK, ATF4, FoxOs, Sirtuins, and mtDNA release, and address the significance of these pathways for stress responses in tumorigenesis and metastasis. In particular, we focus on how mitophagy modulators intersect with cell cycle control and survival pathways in cancer, including following ECM detachment and during cell migration and metastasis. Finally, we interrogate how mitophagy affects tissue atrophy during cancer cachexia and therapy responses in the clinic.
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Affiliation(s)
- Logan P Poole
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL, 60637, USA
- The Committee on Cancer Biology, The University of Chicago, Chicago, USA
| | - Kay F Macleod
- The Ben May Department for Cancer Research, The Gordon Center for Integrative Sciences, W-338, The University of Chicago, 929 E 57th Street, Chicago, IL, 60637, USA.
- The Committee on Cancer Biology, The University of Chicago, Chicago, USA.
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126
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Baek A, Son S, Baek YM, Kim DE. KRT8 (keratin 8) attenuates necrotic cell death by facilitating mitochondrial fission-mediated mitophagy through interaction with PLEC (plectin). Autophagy 2021; 17:3939-3956. [PMID: 33783309 DOI: 10.1080/15548627.2021.1897962] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Dysregulation of mitochondrial homeostasis and accumulation of damaged mitochondria cause degenerative diseases such as age-related macular degeneration (AMD). We studied the effects of the intermediate cytofilament KRT8 (keratin 8) on mitochondrial homeostasis in relation to the morphology and function of mitochondria in retinal pigment epithelial cells under oxidative stress. When the mitochondria were damaged owing to oxidative stress, the damaged mitochondria were readily disposed of via mitophagy following mitochondrial fission. During this process, KRT8 was found to physically interact with the mitochondria through PLEC (plectin) and facilitate the mitochondrial fission-mediated mitophagy. However, the association between PLEC-anchoring mitochondria and KRT8 was dwindled by KRT8 phosphorylation under oxidative stress. The efficient KRT8-facilitated mitophagy flux suppressed the accumulation of damaged mitochondria and consequently diminished necrotic cell death under oxidative stress. Thus, by facilitating mitophagy, KRT8 protects RPE cells against necrotic cell death due to oxidative stress.
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Affiliation(s)
- Ahruem Baek
- Department of Bioscience and Biotechnology, Konkuk University, Gwangjin-gu, Republic of Korea
| | - Sumin Son
- Department of Bioscience and Biotechnology, Konkuk University, Gwangjin-gu, Republic of Korea
| | - Yu Mi Baek
- Department of Bioscience and Biotechnology, Konkuk University, Gwangjin-gu, Republic of Korea
| | - Dong-Eun Kim
- Department of Bioscience and Biotechnology, Konkuk University, Gwangjin-gu, Republic of Korea
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127
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Zhou Q, Zheng Y, Sun Y. Neddylation regulation of mitochondrial structure and functions. Cell Biosci 2021; 11:55. [PMID: 33731189 PMCID: PMC7968265 DOI: 10.1186/s13578-021-00569-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 03/06/2021] [Indexed: 12/11/2022] Open
Abstract
Mitochondria are the powerhouse of a cell. The structure and function of mitochondria are precisely regulated by multiple signaling pathways. Neddylation, a post-translational modification, plays a crucial role in various cellular processes including cellular metabolism via modulating the activity, function and subcellular localization of its substrates. Recently, accumulated data demonstrated that neddylation is involved in regulation of morphology, trafficking and function of mitochondria. Mechanistic elucidation of how mitochondria is modulated by neddylation would further our understanding of mitochondrial regulation to a new level. In this review, we first briefly introduce mitochondria, then neddylation cascade, and known protein substrates subjected to neddylation modification. Next, we summarize current available data of how neddylation enzymes, its substrates (including cullins/Cullin-RING E3 ligases and non-cullins) and its inhibitor MLN4924 regulate the structure and function of mitochondria. Finally, we propose the future perspectives on this emerging and exciting field of mitochondrial research.
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Affiliation(s)
- Qiyin Zhou
- Cancer Institute, The Second Affiliated Hospital, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310029, Zhejiang, China.,Department of Medical Oncology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, Zhejiang, China
| | - Yawen Zheng
- Cancer Institute, The Second Affiliated Hospital, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310029, Zhejiang, China
| | - Yi Sun
- Cancer Institute, The Second Affiliated Hospital, and Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, 310029, Zhejiang, China.
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128
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Onishi M, Okamoto K. Mitochondrial clearance: mechanisms and roles in cellular fitness. FEBS Lett 2021; 595:1239-1263. [PMID: 33615465 DOI: 10.1002/1873-3468.14060] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 01/29/2021] [Accepted: 02/12/2021] [Indexed: 12/14/2022]
Abstract
Mitophagy is one of the selective autophagy pathways that catabolizes dysfunctional or superfluous mitochondria. Under mitophagy-inducing conditions, mitochondria are labeled with specific molecular landmarks that recruit the autophagy machinery to the surface of mitochondria, enclosed into autophagosomes, and delivered to lysosomes (vacuoles in yeast) for degradation. As damaged mitochondria are the major sources of reactive oxygen species, mitophagy is critical for mitochondrial quality control and cellular health. Moreover, appropriate control of mitochondrial quantity via mitophagy is vital for the energy supply-demand balance in cells and whole organisms, cell differentiation, and developmental programs. Thus, it seems conceivable that defects in mitophagy could elicit pleiotropic pathologies such as excess inflammation, tissue injury, neurodegeneration, and aging. In this review, we will focus on the molecular basis and physiological relevance of mitophagy, and potential of mitophagy as a therapeutic target to overcome such disorders.
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Affiliation(s)
- Mashun Onishi
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Koji Okamoto
- Laboratory of Mitochondrial Dynamics, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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129
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Ng MYW, Wai T, Simonsen A. Quality control of the mitochondrion. Dev Cell 2021; 56:881-905. [PMID: 33662258 DOI: 10.1016/j.devcel.2021.02.009] [Citation(s) in RCA: 175] [Impact Index Per Article: 58.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/06/2021] [Accepted: 02/08/2021] [Indexed: 12/22/2022]
Abstract
Mitochondria are essential organelles that execute and coordinate various metabolic processes in the cell. Mitochondrial dysfunction severely affects cell fitness and contributes to disease. Proper organellar function depends on the biogenesis and maintenance of mitochondria and its >1,000 proteins. As a result, the cell has evolved mechanisms to coordinate protein and organellar quality control, such as the turnover of proteins via mitochondria-associated degradation, the ubiquitin-proteasome system, and mitoproteases, as well as the elimination of mitochondria through mitophagy. Specific quality control mechanisms are engaged depending upon the nature and severity of mitochondrial dysfunction, which can also feed back to elicit transcriptional or proteomic remodeling by the cell. Here, we will discuss the current understanding of how these different quality control mechanisms are integrated and overlap to maintain protein and organellar quality and how they may be relevant for cellular and organismal health.
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Affiliation(s)
- Matthew Yoke Wui Ng
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway
| | - Timothy Wai
- Institut Pasteur CNRS UMR 3691, 25-28 Rue du Docteur Roux, Paris, France.
| | - Anne Simonsen
- Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0372 Oslo, Norway; Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, University of Oslo, 0316 Oslo, Norway.
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130
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A Destiny for Degradation: Interplay between Cullin-RING E3 Ligases and Autophagy. Trends Cell Biol 2021; 31:432-444. [PMID: 33573849 DOI: 10.1016/j.tcb.2021.01.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/09/2021] [Accepted: 01/14/2021] [Indexed: 12/13/2022]
Abstract
Autophagy and the ubiquitin-proteasome system (UPS) are two major pathways for protein degradation. The cullin-RING E3 ligases (CRLs) are the largest E3 ligase family and have key biological functions in maintaining protein homeostasis. We provide an updated review of the interactions between CRLs and autophagy, focusing on the regulatory effects of CRLs on the core autophagy machinery that consists of several autophagy-related protein (ATG) complexes and their key upstream signaling pathways. The involvement of such functional interactions in health and disease is also discussed. Understanding the role of CRLs in autophagy is helpful for the development of therapeutic strategies for diseases in which CRLs and autophagy are dysregulated, such as cancer and neurodegenerative conditions.
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131
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Li Y, Lin Y, Han X, Li W, Yan W, Ma Y, Lu X, Huang X, Bai R, Zhang H. GSK3 inhibitor ameliorates steatosis through the modulation of mitochondrial dysfunction in hepatocytes of obese patients. iScience 2021; 24:102149. [PMID: 33665568 PMCID: PMC7900441 DOI: 10.1016/j.isci.2021.102149] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 12/30/2020] [Accepted: 02/02/2021] [Indexed: 12/30/2022] Open
Abstract
Obesity is an important risk factor and a potential treatment target for hepatic steatosis. The maladaptation of hepatic mitochondrial flexibility plays a key role in the hepatic steatosis. Herein, we found that hepatocyte-like cells derived from human adipose stem cell of obese patients exhibited the characteristics of hepatic steatosis and accompanied with lower expression of the subunits of mitochondrial complex I and lower oxidative phosphorylation levels. The GSK3 inhibitor CHIR-99021 promoted the expression of NDUFB8, NDUFB9, the subunits of mitochondrial complex I, the basal oxygen consumption rate, and the fatty acid oxidation of the hepatocytes of obese patients by upregulating the expression of the transcription factor PGC-1α, TFAM, and NRF1 involved in mitochondrial biogenesis. Moreover, CHIR-99021 decreased the lipid droplets size and the triglyceride levels in hepatocytes of obese patients. The results demonstrate that GSK3 inhibition ameliorates hepatic steatosis by elevating the mitochondrial function in hepatocytes of obese patients. Obese patients’ adipose-stem-cell-derived hepatocytes reveal hepatic steatosis Hepatic steatosis is accompanied the mitochondrial dysfunction The mitochondrial dysfunction is governed by the low expression PGC-1α, TFAM, and NRF1 GSK3 inhibitor ameliorates hepatic steatosis via mitochondrial dysfunction modulation
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Affiliation(s)
- Yaqiong Li
- Department of Cell Biology, School of Basic Medical Science, Capital Medical University, Beijing, 100069, China
| | - Yi Lin
- Department of General Surgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, 100070, China
| | - Xueya Han
- Department of Cell Biology, School of Basic Medical Science, Capital Medical University, Beijing, 100069, China
| | - Weihong Li
- Department of Cell Biology, School of Basic Medical Science, Capital Medical University, Beijing, 100069, China
| | - Wenmao Yan
- Department of General Surgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, 100070, China
| | - Yuejiao Ma
- Department of Cell Biology, School of Basic Medical Science, Capital Medical University, Beijing, 100069, China
| | - Xin Lu
- Department of Cell Biology, School of Basic Medical Science, Capital Medical University, Beijing, 100069, China
| | - Xiaowu Huang
- Fu Xing Hospital, Capital Medical University, Beijing, 100038, China
| | - Rixing Bai
- Department of General Surgery, Beijing Tian Tan Hospital, Capital Medical University, Beijing, 100070, China
- Corresponding author
| | - Haiyan Zhang
- Department of Cell Biology, School of Basic Medical Science, Capital Medical University, Beijing, 100069, China
- Corresponding author
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132
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Wen F, Shi Z, Liu X, Tan Y, Wei L, Zhu X, Zhang H, Zhu X, Meng X, Ji W, Yang M, Lu Z. Acute Elevated Resistin Exacerbates Mitochondrial Damage and Aggravates Liver Steatosis Through AMPK/PGC-1α Signaling Pathway in Male NAFLD Mice. Horm Metab Res 2021; 53:132-144. [PMID: 33302316 DOI: 10.1055/a-1293-8250] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Resistin was identified as a link between obesity and insulin resistance and is associated with many diseases in mice. Deciphering the related development and molecular mechanism is necessary for the treatment of these diseases. Previous studies have revealed that increased resistin levels are correlated with lipid accumulation and play a role in non-alcoholic fatty liver disease (NAFLD) development. However, the exact mechanisms underlying these processes remain unclear. To further clarify whether acute elevated resistin level exacerbated liver steatosis, a high-fat diet-induced NAFLD animal model was used and treated with or without resistin for 6 days. We discovered that resistin altered mitochondrial morphology, decreased mitochondrial content, and increased lipid accumulation in HFD mice. qRT-PCR and western blot analysis showed that acute elevated resistin significantly altered the gene expression of mitochondrial biogenesis and liver lipid metabolism molecules in HFD mice. Consequently, in vitro experiments verified that resistin reduced the mitochondrial content, impaired the mitochondrial function and increased the lipid accumulation of palmitate-treated HepG2 cells. Additionally, we demonstrated that resistin upregulated proinflammatory factors, which confirmed that resistin promoted the development of inflammation in NAFLD mice and palmitate-treated HepG2 cells. Signaling-transduction analysis demonstrated that acute elevated resistin aggravated liver steatosis through AMPK/PGC-1α pathway in male mice. This reveals a novel pathway through which lipogenesis is induced by resistin and suggests that maintaining mitochondrial homeostasis may be key to treatments for preventing resistin-induced NAFLD aggravation.
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Affiliation(s)
- Fengyun Wen
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Zhuoyan Shi
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Xiaoping Liu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Yuguang Tan
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Lan Wei
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Xuemin Zhu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Hui Zhang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Xiaohuan Zhu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Xiangmiao Meng
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Weixia Ji
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Mengting Yang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
| | - Zhaoxuan Lu
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, Henan, P. R. China
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133
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Onishi M, Yamano K, Sato M, Matsuda N, Okamoto K. Molecular mechanisms and physiological functions of mitophagy. EMBO J 2021; 40:e104705. [PMID: 33438778 PMCID: PMC7849173 DOI: 10.15252/embj.2020104705] [Citation(s) in RCA: 622] [Impact Index Per Article: 207.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 08/03/2020] [Accepted: 10/02/2020] [Indexed: 12/12/2022] Open
Abstract
Degradation of mitochondria via a selective form of autophagy, named mitophagy, is a fundamental mechanism conserved from yeast to humans that regulates mitochondrial quality and quantity control. Mitophagy is promoted via specific mitochondrial outer membrane receptors, or ubiquitin molecules conjugated to proteins on the mitochondrial surface leading to the formation of autophagosomes surrounding mitochondria. Mitophagy-mediated elimination of mitochondria plays an important role in many processes including early embryonic development, cell differentiation, inflammation, and apoptosis. Recent advances in analyzing mitophagy in vivo also reveal high rates of steady-state mitochondrial turnover in diverse cell types, highlighting the intracellular housekeeping role of mitophagy. Defects in mitophagy are associated with various pathological conditions such as neurodegeneration, heart failure, cancer, and aging, further underscoring the biological relevance. Here, we review our current molecular understanding of mitophagy, and its physiological implications, and discuss how multiple mitophagy pathways coordinately modulate mitochondrial fitness and populations.
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Affiliation(s)
- Mashun Onishi
- Laboratory of Mitochondrial DynamicsGraduate School of Frontier BiosciencesOsaka UniversitySuitaJapan
| | - Koji Yamano
- The Ubiquitin ProjectTokyo Metropolitan Institute of Medical ScienceTokyoJapan
| | - Miyuki Sato
- Laboratory of Molecular Membrane BiologyInstitute for Molecular and Cellular RegulationGunma UniversityMaebashiJapan
| | - Noriyuki Matsuda
- The Ubiquitin ProjectTokyo Metropolitan Institute of Medical ScienceTokyoJapan
| | - Koji Okamoto
- Laboratory of Mitochondrial DynamicsGraduate School of Frontier BiosciencesOsaka UniversitySuitaJapan
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134
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Function and regulation of the divisome for mitochondrial fission. Nature 2021; 590:57-66. [PMID: 33536648 DOI: 10.1038/s41586-021-03214-x] [Citation(s) in RCA: 204] [Impact Index Per Article: 68.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/04/2020] [Indexed: 01/30/2023]
Abstract
Mitochondria form dynamic networks in the cell that are balanced by the flux of iterative fusion and fission events of the organelles. It is now appreciated that mitochondrial fission also represents an end-point event in a signalling axis that allows cells to sense and respond to external cues. The fission process is orchestrated by membrane-associated adaptors, influenced by organellar and cytoskeletal interactions and ultimately executed by the dynamin-like GTPase DRP1. Here we invoke the framework of the 'mitochondrial divisome', which is conceptually and operationally similar to the bacterial cell-division machinery. We review the functional and regulatory aspects of the mitochondrial divisome and, within this framework, parse the core from the accessory machinery. In so doing, we transition from a phenomenological to a mechanistic understanding of the fission process.
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135
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Kouroumalis E, Voumvouraki A, Augoustaki A, Samonakis DN. Autophagy in liver diseases. World J Hepatol 2021; 13:6-65. [PMID: 33584986 PMCID: PMC7856864 DOI: 10.4254/wjh.v13.i1.6] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 12/10/2020] [Accepted: 12/26/2020] [Indexed: 02/06/2023] Open
Abstract
Autophagy is the liver cell energy recycling system regulating a variety of homeostatic mechanisms. Damaged organelles, lipids and proteins are degraded in the lysosomes and their elements are re-used by the cell. Investigations on autophagy have led to the award of two Nobel Prizes and a health of important reports. In this review we describe the fundamental functions of autophagy in the liver including new data on the regulation of autophagy. Moreover we emphasize the fact that autophagy acts like a two edge sword in many occasions with the most prominent paradigm being its involvement in the initiation and progress of hepatocellular carcinoma. We also focused to the implication of autophagy and its specialized forms of lipophagy and mitophagy in the pathogenesis of various liver diseases. We analyzed autophagy not only in well studied diseases, like alcoholic and nonalcoholic fatty liver and liver fibrosis but also in viral hepatitis, biliary diseases, autoimmune hepatitis and rare diseases including inherited metabolic diseases and also acetaminophene hepatotoxicity. We also stressed the different consequences that activation or impairment of autophagy may have in hepatocytes as opposed to Kupffer cells, sinusoidal endothelial cells or hepatic stellate cells. Finally, we analyzed the limited clinical data compared to the extensive experimental evidence and the possible future therapeutic interventions based on autophagy manipulation.
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Affiliation(s)
- Elias Kouroumalis
- Liver Research Laboratory, University of Crete Medical School, Heraklion 71110, Greece
| | - Argryro Voumvouraki
- 1 Department of Internal Medicine, AHEPA University Hospital, Thessaloniki 54636, Greece
| | - Aikaterini Augoustaki
- Department of Gastroenterology and Hepatology, University Hospital of Crete, Heraklion 71110, Greece
| | - Dimitrios N Samonakis
- Department of Gastroenterology and Hepatology, University Hospital of Crete, Heraklion 71110, Greece.
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136
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Guo YF, Su T, Yang M, Li CJ, Guo Q, Xiao Y, Huang Y, Liu Y, Luo XH. The role of autophagy in bone homeostasis. J Cell Physiol 2021; 236:4152-4173. [PMID: 33452680 DOI: 10.1002/jcp.30111] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/24/2020] [Accepted: 10/05/2020] [Indexed: 12/15/2022]
Abstract
Autophagy is an evolutionarily conserved intracellular process and is considered one of the main catabolism pathways. In the process of autophagy, cells are digested nonselectively or selectively to recover nutrients and energy, so it is regarded as an antiaging process. In addition to the essential role of autophagy in cellular homeostasis, autophagy is a stress response mechanism for cell survival. Here, we review recent literature describing the pathway of autophagy and its role in different bone cell types, including osteoblasts, osteoclasts, and osteocytes. Also discussed is the mechanism of autophagy in bone diseases associated with bone homeostasis, including osteoporosis and Paget's disease. Finally, we discuss the application of autophagy regulators in bone diseases. This review aims to introduce autophagy, summarize the understanding of its relevance in bone physiology, and discuss its role and therapeutic potential in the pathogenesis of bone diseases such as osteoporosis.
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Affiliation(s)
- Yi-Fan Guo
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Tian Su
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Mi Yang
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Chang-Jun Li
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Qi Guo
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Ye Xiao
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yan Huang
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Ya Liu
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Xiang-Hang Luo
- Department of Endocrinology, Endocrinology Research Center, Xiangya Hospital of Central South University, Changsha, Hunan, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital of Central South University, Changsha, Hunan, China
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137
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Yabiku K. Efficacy of Sodium-Glucose Cotransporter 2 Inhibitors in Patients With Concurrent Type 2 Diabetes Mellitus and Non-Alcoholic Steatohepatitis: A Review of the Evidence. Front Endocrinol (Lausanne) 2021; 12:768850. [PMID: 34950104 PMCID: PMC8688740 DOI: 10.3389/fendo.2021.768850] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/19/2021] [Indexed: 12/12/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, and more than half of individuals diagnosed with type 2 diabetes concurrently present with NAFLD. There is a bidirectional pathological relationship between the two conditions, whereby NAFLD increases the risk of type 2 diabetes, and type 2 diabetes contributes to and accelerates the progression of NAFLD. Furthermore, over 30% of patients with NAFLD progress to non-alcoholic liver steatohepatitis (NASH), which then increases the risk of cirrhosis and hepatocellular carcinoma. Despite its high prevalence and the potential clinical implications, the underlying pathogenesis of NAFLD has yet to be fully elucidated, and there is no consensus regarding standard diagnosis and treatment for either NALFD or NASH. As patients with both NASH and type 2 diabetes have impaired hepatic function owing to chronic inflammation and the resulting structural changes caused by hepatic fat accumulation, they face reduced options for antidiabetic treatment. SGLT-2 inhibitors inhibit glucose reabsorption in the proximal tubule, with increased excretion of glucose in urine and decreased glucose levels in plasma, and their glycemia-lowering effect is insulin-independent. Several other beneficial effects have been reported for SGLT-2 inhibitors, including reduced risks of cardiovascular and renal diseases, improved blood pressure control, body weight reduction, and reductions in liver fat content. Experimental studies in mouse models have suggested that SGLT-2 inhibitors may have beneficial modulatory effects on NAFLD/NASH. Several trials in patients with type 2 diabetes have also suggested that these drugs may be useful in treating both type 2 diabetes and NAFLD or NASH. However, further research is needed to identify the mechanisms by which SGLT-2 inhibitors affect fatty liver and steatohepatitis. In this state-of-the-art review, we explore the literature on the efficacy of SGLT-2 inhibitors in patients with type 2 diabetes and NASH, and present arguments for and against the use of SGLT-2 inhibitors in this patient population.
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138
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Abstract
Background Mitochondrial oxidative function plays a key role in the development of non-alcoholic fatty liver disease (NAFLD) and insulin resistance (IR). Recent studies reported that fatty liver might not be a result of decreased mitochondrial fat oxidation caused by mitochondrial damage. Rather, NAFLD and IR induce an elevation in mitochondrial function that covers the increased demand for carbon intermediates and ATP caused by elevated lipogenesis and gluconeogenesis. Furthermore, mitochondria play a role in regulating hepatic insulin sensitivity and lipogenesis by modulating redox-sensitive signaling pathways. Scope of review We review the contradictory studies indicating that NAFLD and hyperglycemia can either increase or decrease mitochondrial oxidative capacity in the liver. We summarize mechanisms regulating mitochondrial heterogeneity inside the same cell and discuss how these mechanisms may determine the role of mitochondria in NAFLD. We further discuss the role of endogenous antioxidants in controlling mitochondrial H2O2 release and redox-mediated signaling. We describe the emerging concept that the subcellular location of cellular antioxidants is a key determinant of their effects on NAFLD. Major conclusions The balance of fat oxidation versus accumulation depends on mitochondrial fuel preference rather than ATP-synthesizing respiration. As such, therapies targeting fuel preference might be more suitable for treating NAFLD. Similarly, suppressing maladaptive antioxidants, rather than interfering with physiological mitochondrial H2O2-mediated signaling, may allow the maintenance of intact hepatic insulin signaling in NAFLD. Exploration of the subcellular compartmentalization of different antioxidant systems and the unique functions of specific mitochondrial subpopulations may offer new intervention points to treat NAFLD. Mitochondrial function has been reported to be increased or decreased in NAFLD. Functionally independent subpopulations of mitochondria can clarify the conundrum of these conflicting reports. Maladaptive antioxidants decreasing mitochondrial H2O2 and promoting NAFLD are discussed. Therapies targeting mitochondria to treat NAFLD are discussed.
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139
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Baiges-Gaya G, Fernández-Arroyo S, Luciano-Mateo F, Cabré N, Rodríguez-Tomàs E, Hernández-Aguilera A, Castañé H, Romeu M, Nogués MR, Camps J, Joven J. Hepatic metabolic adaptation and adipose tissue expansion are altered in mice with steatohepatitis induced by high-fat high sucrose diet. J Nutr Biochem 2020; 89:108559. [PMID: 33264665 DOI: 10.1016/j.jnutbio.2020.108559] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 10/05/2020] [Accepted: 11/21/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Obesity is a chronic progressive disease with several metabolic alterations. Nonalcoholic fatty liver disease (NAFLD) is an important comorbidity of obesity that can progress to nonalcoholic steatohepatitis (NASH), cirrhosis or hepatocarcinoma. This study aimed at clarifying the molecular mechanisms underlying the metabolic alterations in hepatic and adipose tissue during high-fat high-sucrose diet-induced NAFLD development in mice. METHODS Twenty-four male mice (C57BL/6J) were randomly allocated into 3 groups (n = 8 mice per group) to receive a chow diet, a high-fat diet (HFD), or a high-fat high-sucrose diet (HF-HSD) for 20 weeks. At sacrifice, liver and adipose tissue were obtained for histopathological, metabolomic, and protein expression analyses. RESULTS HF-HSD (but not HFD) was associated with NASH and increased oxidative stress. These animals presented an inhibition of hepatic autophagy and alterations in AMP-activated protein kinase/mammalian target of rapamycin activity. We also observed that the ability of metabolic adaptation was adversely affected by the increase of damaged mitochondria. NASH development was associated with changes in adipose tissue dynamics and increased amounts of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids in visceral adipose tissue. CONCLUSION HF-HSD led to a metabolic blockage and impaired hepatic mitochondria turnover. In addition, the continuous accumulation of fatty acids produced adipose tissue dysfunction and hepatic fat accumulation that favored the progression to NASH.
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Affiliation(s)
- Gerard Baiges-Gaya
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain
| | - Salvador Fernández-Arroyo
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain
| | - Fedra Luciano-Mateo
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain
| | - Noemí Cabré
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain
| | - Elisabet Rodríguez-Tomàs
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain
| | - Anna Hernández-Aguilera
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain
| | - Helena Castañé
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain
| | - Marta Romeu
- Universitat Rovira i Virgili, Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Unitat de Farmacologia, Reus, Spain
| | - Maria-Rosa Nogués
- Universitat Rovira i Virgili, Departament de Ciències Mèdiques Bàsiques, Facultat de Medicina, Unitat de Farmacologia, Reus, Spain
| | - Jordi Camps
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain.
| | - Jorge Joven
- Universitat Rovira i Virgili, Departament de Medicina i Cirurgia, Facultat de Medicina, Reus, Spain; Unitat de Recerca Biomèdica, Hospital Universitari de Sant Joan, Institut d'investigació Sanitària Pere Virgili, Reus, Spain; Campus of International Excellence Southern Catalonia, Tarragona, Spain.
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140
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Murata D, Yamada T, Tokuyama T, Arai K, Quirós PM, López-Otín C, Iijima M, Sesaki H. Mitochondrial Safeguard: a stress response that offsets extreme fusion and protects respiratory function via flickering-induced Oma1 activation. EMBO J 2020; 39:e105074. [PMID: 33200421 DOI: 10.15252/embj.2020105074] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 10/15/2020] [Accepted: 10/22/2020] [Indexed: 12/22/2022] Open
Abstract
The connectivity of mitochondria is regulated by a balance between fusion and division. Many human diseases are associated with excessive mitochondrial connectivity due to impaired Drp1, a dynamin-related GTPase that mediates division. Here, we report a mitochondrial stress response, named mitochondrial safeguard, that adjusts the balance of fusion and division in response to increased mitochondrial connectivity. In cells lacking Drp1, mitochondria undergo hyperfusion. However, hyperfusion does not completely connect mitochondria because Opa1 and mitofusin 1, two other dynamin-related GTPases that mediate fusion, become proteolytically inactivated. Pharmacological and genetic experiments show that the activity of Oma1, a metalloprotease that cleaves Opa1, is regulated by short pulses of the membrane depolarization without affecting the overall membrane potential in Drp1-knockout cells. Re-activation of Opa1 and Mitofusin 1 in Drp1-knockout cells further connects mitochondria beyond hyperfusion, termed extreme fusion, leading to bioenergetic deficits. These findings reveal an unforeseen safeguard mechanism that prevents extreme fusion of mitochondria, thereby maintaining mitochondrial function when the balance is shifted to excessive connectivity.
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Affiliation(s)
- Daisuke Murata
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tatsuya Yamada
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Takeshi Tokuyama
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kenta Arai
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Pedro M Quirós
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología, Universidad de Oviedo, Oviedo, Spain
| | - Carlos López-Otín
- Departamento de Bioquímica y Biología Molecular, Facultad de Medicina, Instituto Universitario de Oncología, Universidad de Oviedo, Oviedo, Spain
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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141
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MAVS is energized by Mff which senses mitochondrial metabolism via AMPK for acute antiviral immunity. Nat Commun 2020; 11:5711. [PMID: 33177519 PMCID: PMC7658986 DOI: 10.1038/s41467-020-19287-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 10/07/2020] [Indexed: 12/17/2022] Open
Abstract
Mitochondria are multifunctional organelles that produce energy and are critical for various signaling pathways. Mitochondrial antiviral signaling (MAVS) is a mitochondrial outer membrane protein essential for the anti-RNA viral immune response, which is regulated by mitochondrial dynamics and energetics; however, the molecular link between mitochondrial metabolism and immunity is unclear. Here we show in cultured mammalian cells that MAVS is activated by mitochondrial fission factor (Mff), which senses mitochondrial energy status. Mff mediates the formation of active MAVS clusters on mitochondria, independent of mitochondrial fission and dynamin-related protein 1. Under mitochondrial dysfunction, Mff is phosphorylated by the cellular energy sensor AMP-activated protein kinase (AMPK), leading to the disorganization of MAVS clusters and repression of the acute antiviral response. Mff also contributes to immune tolerance during chronic infection by disrupting the mitochondrial MAVS clusters. Taken together, Mff has a critical function in MAVS-mediated innate immunity, by sensing mitochondrial energy metabolism via AMPK signaling.
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142
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Adachi Y, Kato T, Yamada T, Murata D, Arai K, Stahelin RV, Chan DC, Iijima M, Sesaki H. Drp1 Tubulates the ER in a GTPase-Independent Manner. Mol Cell 2020; 80:621-632.e6. [PMID: 33152269 DOI: 10.1016/j.molcel.2020.10.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 09/10/2020] [Accepted: 10/09/2020] [Indexed: 01/08/2023]
Abstract
Mitochondria are highly dynamic organelles that continuously grow, divide, and fuse. The division of mitochondria is crucial for human health. During mitochondrial division, the mechano-guanosine triphosphatase (GTPase) dynamin-related protein (Drp1) severs mitochondria at endoplasmic reticulum (ER)-mitochondria contact sites, where peripheral ER tubules interact with mitochondria. Here, we report that Drp1 directly shapes peripheral ER tubules in human and mouse cells. This ER-shaping activity is independent of GTP hydrolysis and located in a highly conserved peptide of 18 amino acids (termed D-octadecapeptide), which is predicted to form an amphipathic α helix. Synthetic D-octadecapeptide tubulates liposomes in vitro and the ER in cells. ER tubules formed by Drp1 promote mitochondrial division by facilitating ER-mitochondria interactions. Thus, Drp1 functions as a two-in-one protein during mitochondrial division, with ER tubulation and mechano-GTPase activities.
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Affiliation(s)
- Yoshihiro Adachi
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Takashi Kato
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Tatsuya Yamada
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daisuke Murata
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kenta Arai
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Robert V Stahelin
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - David C Chan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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143
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Long M, McWilliams TG. Monitoring autophagy in cancer: From bench to bedside. Semin Cancer Biol 2020; 66:12-21. [DOI: 10.1016/j.semcancer.2019.05.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/06/2019] [Accepted: 05/27/2019] [Indexed: 12/29/2022]
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144
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Craig JE, Miller JN, Rayavarapu RR, Hong Z, Bulut GB, Zhuang W, Sakurada SM, Temirov J, Low JA, Chen T, Pruett-Miller SM, Huang LJS, Potts MB. MEKK3-MEK5-ERK5 signaling promotes mitochondrial degradation. Cell Death Discov 2020; 6:107. [PMID: 33101709 PMCID: PMC7576125 DOI: 10.1038/s41420-020-00342-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 09/09/2020] [Accepted: 09/28/2020] [Indexed: 12/26/2022] Open
Abstract
Mitochondria are vital organelles that coordinate cellular energy homeostasis and have important roles in cell death. Therefore, the removal of damaged or excessive mitochondria is critical for maintaining proper cellular function. The PINK1-Parkin pathway removes acutely damaged mitochondria through a well-characterized mitophagy pathway, but basal mitochondrial turnover occurs via distinct and less well-understood mechanisms. Here we report that the MEKK3-MEK5-ERK5 kinase cascade is required for mitochondrial degradation in the absence of exogenous damage. We demonstrate that genetic or pharmacological inhibition of the MEKK3-MEK5-ERK5 pathway increases mitochondrial content by reducing lysosome-mediated degradation of mitochondria under basal conditions. We show that the MEKK3-MEK5-ERK5 pathway plays a selective role in basal mitochondrial degradation but is not required for non-selective bulk autophagy, damage-induced mitophagy, or restraint of mitochondrial biogenesis. This illuminates the MEKK3-MEK5-ERK5 pathway as a positive regulator of mitochondrial degradation that acts independently of exogenous mitochondrial stressors.
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Affiliation(s)
- Jane E Craig
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA.,Integrated Biomedical Sciences Program, University of Tennessee Health Science Center, Memphis, Tennessee 38163 USA
| | - Joseph N Miller
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA.,Integrated Biomedical Sciences Program, University of Tennessee Health Science Center, Memphis, Tennessee 38163 USA
| | - Raju R Rayavarapu
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
| | - Zhenya Hong
- Department of Cell Biology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390 USA.,Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Gamze B Bulut
- Department of Cell Biology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390 USA
| | - Wei Zhuang
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
| | - Sadie Miki Sakurada
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
| | - Jamshid Temirov
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
| | - Jonathan A Low
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
| | - Shondra M Pruett-Miller
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
| | - Lily Jun-Shen Huang
- Department of Cell Biology, The University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390 USA
| | - Malia B Potts
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 USA
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145
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Murata D, Arai K, Iijima M, Sesaki H. Mitochondrial division, fusion and degradation. J Biochem 2020; 167:233-241. [PMID: 31800050 DOI: 10.1093/jb/mvz106] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 11/17/2019] [Indexed: 12/11/2022] Open
Abstract
The mitochondrion is an essential organelle for a wide range of cellular processes, including energy production, metabolism, signal transduction and cell death. To execute these functions, mitochondria regulate their size, number, morphology and distribution in cells via mitochondrial division and fusion. In addition, mitochondrial division and fusion control the autophagic degradation of dysfunctional mitochondria to maintain a healthy population. Defects in these dynamic membrane processes are linked to many human diseases that include metabolic syndrome, myopathy and neurodegenerative disorders. In the last several years, our fundamental understanding of mitochondrial fusion, division and degradation has been significantly advanced by high resolution structural analyses, protein-lipid biochemistry, super resolution microscopy and in vivo analyses using animal models. Here, we summarize and discuss this exciting recent progress in the mechanism and function of mitochondrial division and fusion.
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Affiliation(s)
- Daisuke Murata
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Kenta Arai
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Miho Iijima
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
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146
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Exaggerated Autophagy in Stanford Type A Aortic Dissection: A Transcriptome Pilot Analysis of Human Ascending Aortic Tissues. Genes (Basel) 2020; 11:genes11101187. [PMID: 33066131 PMCID: PMC7650806 DOI: 10.3390/genes11101187] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/25/2020] [Accepted: 10/09/2020] [Indexed: 02/08/2023] Open
Abstract
Stanford type A aortic dissection (TAAD) is one of the most dangerous diseases of acute aortic syndrome. Molecular pathological studies on TAAD can aid in understanding the disease comprehensively and can provide insights into new diagnostic markers and potential therapeutic targets. In this study, we defined the molecular pathology of TAAD by performing transcriptome sequencing of human ascending aortic tissues. Pathway analysis revealed that activated inflammation, cell death and smooth muscle cell degeneration are the main pathological changes in aortic dissection. However, autophagy is considered to be one of the most important biological processes, regulating inflammatory reactions and degenerative changes. Therefore, we focused on the pathological role of autophagy in aortic dissection and identified 10 autophagy-regulated hub genes, which are all upregulated in TAAD. These results indicate that exaggerated autophagy participates in the pathological process of aortic dissection and may provide new insight for further basic research on TAAD.
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147
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Wang H, Wang Z, Li Z, Lee TY. Incorporating Deep Learning With Word Embedding to Identify Plant Ubiquitylation Sites. Front Cell Dev Biol 2020; 8:572195. [PMID: 33102477 PMCID: PMC7554246 DOI: 10.3389/fcell.2020.572195] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/24/2020] [Indexed: 12/17/2022] Open
Abstract
Protein ubiquitylation is an important posttranslational modification (PTM), which is involved in diverse biological processes and plays an essential role in the regulation of physiological mechanisms and diseases. The Protein Lysine Modifications Database (PLMD) has accumulated abundant ubiquitylated proteins with their substrate sites for more than 20 kinds of species. Numerous works have consequently developed a variety of ubiquitylation site prediction tools across all species, mainly relying on the predefined sequence features and machine learning algorithms. However, the difference in ubiquitylated patterns between these species stays unclear. In this work, the sequence-based characterization of ubiquitylated substrate sites has revealed remarkable differences among plants, animals, and fungi. Then an improved word-embedding scheme based on the transfer learning strategy was incorporated with the multilayer convolutional neural network (CNN) for identifying protein ubiquitylation sites. For the prediction of plant ubiquitylation sites, the proposed deep learning scheme could outperform the machine learning-based methods, with the accuracy of 75.6%, precision of 73.3%, recall of 76.7%, F-score of 0.7493, and 0.82 AUC on the independent testing set. Although the ubiquitylated specificity of substrate sites is complicated, this work has demonstrated that the application of the word-embedding method can enable the extraction of informative features and help the identification of ubiquitylated sites. To accelerate the investigation of protein ubiquitylation, the data sets and source code used in this study are freely available at https://github.com/wang-hong-fei/DL-plant-ubsites-prediction.
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Affiliation(s)
- Hongfei Wang
- Warshel Institute for Computational Biology, The Chinese University of Hong Kong, Shenzhen, China
| | - Zhuo Wang
- Warshel Institute for Computational Biology, The Chinese University of Hong Kong, Shenzhen, China.,School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Zhongyan Li
- Warshel Institute for Computational Biology, The Chinese University of Hong Kong, Shenzhen, China.,School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, China
| | - Tzong-Yi Lee
- Warshel Institute for Computational Biology, The Chinese University of Hong Kong, Shenzhen, China.,School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen, China
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148
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Wang Y, An H, Liu T, Qin C, Sesaki H, Guo S, Radovick S, Hussain M, Maheshwari A, Wondisford FE, O'Rourke B, He L. Metformin Improves Mitochondrial Respiratory Activity through Activation of AMPK. Cell Rep 2020; 29:1511-1523.e5. [PMID: 31693892 PMCID: PMC6866677 DOI: 10.1016/j.celrep.2019.09.070] [Citation(s) in RCA: 221] [Impact Index Per Article: 55.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/11/2019] [Accepted: 09/23/2019] [Indexed: 12/25/2022] Open
Abstract
Impaired mitochondrial respiratory activity contributes to the development of insulin resistance in type 2 diabetes. Metformin, a first-line antidiabetic drug, functions mainly by improving patients’ hyperglycemia and insulin resistance. However, its mechanism of action is still not well understood. We show here that pharmacological metformin concentration increases mitochondrial respiration, membrane potential, and ATP levels in hepatocytes and a clinically relevant metformin dose increases liver mitochondrial density and complex 1 activity along with improved hyperglycemia in high-fat- diet (HFD)-fed mice. Metformin, functioning through 5′ AMP-activated protein kinase (AMPK), promotes mitochondrial fission to improve mitochondrial respiration and restore the mitochondrial life cycle. Furthermore, HFD-fed-mice with liver-specific knockout of AMPKα1/2 subunits exhibit higher blood glucose levels when treated with metformin. Our results demonstrate that activation of AMPK by metformin improves mitochondrial respiration and hyperglycemia in obesity. We also found that supra-pharmacological metformin concentrations reduce adenine nucleotides, resulting in the halt of mitochondrial respiration. These findings suggest a mechanism for metformin’s anti-tumor effects. The mechanism of metformin action still remains controversial, in particular on mitochondrial activity and the involvement of AMPK. Wang et al. show that pharmacological metformin concentration or dose improves mitochondrial respiration by increasing mitochondrial fission through AMPK-Mff signaling; in contrast, supra-pharmacological metformin concentrations reduce mitochondrial respiration through decreasing adenine nucleotide levels.
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Affiliation(s)
- Yu Wang
- Division of Neonatology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Hongying An
- Division of Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Ting Liu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Caolitao Qin
- Division of Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Hiromi Sesaki
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Shaodong Guo
- Department of Nutrition and Food Science, Texas A&M University, TX 77843, USA
| | - Sally Radovick
- Departments of Pediatrics and Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Mehboob Hussain
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48105, USA
| | - Akhil Maheshwari
- Division of Neonatology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Fredric E Wondisford
- Departments of Pediatrics and Medicine, Rutgers-Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
| | - Brian O'Rourke
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Ling He
- Division of Neonatology, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Division of Metabolism, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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149
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Joaquim M, Escobar-Henriques M. Role of Mitofusins and Mitophagy in Life or Death Decisions. Front Cell Dev Biol 2020; 8:572182. [PMID: 33072754 PMCID: PMC7539839 DOI: 10.3389/fcell.2020.572182] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 09/03/2020] [Indexed: 12/12/2022] Open
Abstract
Mitochondria entail an incredible dynamism in their morphology, impacting death signaling and selective elimination of the damaged organelles. In turn, by recycling the superfluous or malfunctioning mitochondria, mostly prevalent during aging, mitophagy contributes to maintain a healthy mitochondrial network. Mitofusins locate at the outer mitochondrial membrane and control the plastic behavior of mitochondria, by mediating fusion events. Besides deciding on mitochondrial interconnectivity, mitofusin 2 regulates physical contacts between mitochondria and the endoplasmic reticulum, but also serves as a decisive docking platform for mitophagy and apoptosis effectors. Thus, mitofusins integrate multiple bidirectional inputs from and into mitochondria and ensure proper energetic and metabolic cellular performance. Here, we review the role of mitofusins and mitophagy at the cross-road between life and apoptotic death decisions. Furthermore, we highlight the impact of this interplay on disease, focusing on how mitofusin 2 and mitophagy affect non-alcoholic fatty liver disease.
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Affiliation(s)
- Mariana Joaquim
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Mafalda Escobar-Henriques
- Institute for Genetics, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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150
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Yang X, Zhang R, Nakahira K, Gu Z. Mitochondrial DNA Mutation, Diseases, and Nutrient-Regulated Mitophagy. Annu Rev Nutr 2020; 39:201-226. [PMID: 31433742 DOI: 10.1146/annurev-nutr-082018-124643] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A wide spectrum of human diseases, including cancer, neurodegenerative diseases, and metabolic disorders, have been shown to be associated with mitochondrial dysfunction through multiple molecular mechanisms. Mitochondria are particularly susceptible to nutrient deficiencies, and nutritional intervention is an essential way to maintain mitochondrial homeostasis. Recent advances in genetic manipulation and next-generation sequencing reveal the crucial roles of mitochondrial DNA (mtDNA) in various pathophysiological conditions. Mitophagy, a term coined to describe autophagy that targets dysfunctional mitochondria, has emerged as an important cellular process to maintain mitochondrial homeostasis and has been shown to be regulated by various nutrients and nutritional stresses. Given the high prevalence of mtDNA mutations in humans and their impact on mitochondrial function, it is important to investigate the mechanisms that regulate mtDNA mutation. Here, we discuss mitochondrial genetics and mtDNA mutations and their implications for human diseases. We also examine the role of mitophagy as a therapeutic target, highlighting how nutrients may eliminate mtDNA mutations through mitophagy.
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Affiliation(s)
- Xuan Yang
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA; , ,
| | - Ruoyu Zhang
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA; , ,
| | - Kiichi Nakahira
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, NY 10065, USA;
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA; , ,
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