1
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Wei J, Zhang M, Wang X, Yang K, Xiao Q, Zhu X, Pan X. Role of cardiolipin in regulating and treating atherosclerotic cardiovascular diseases. Eur J Pharmacol 2024; 979:176853. [PMID: 39067567 DOI: 10.1016/j.ejphar.2024.176853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 07/10/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Cardiovascular diseases, mainly caused by atherosclerosis, are the leading causes of morbidity and mortality worldwide. Despite the discrepancies in clinical manifestations between different abnormalities, atherosclerosis shares similar pathophysiological processes, such as mitochondrial dysfunction. Cardiolipin (CL) is a conserved mitochondria-specific lipid that contributes to the cristae structure of the inner mitochondrial membrane (IMM). Alterations in the CL, including oxidative modification, reduced quantity, and abnormal localization, contribute to the onset and progression of atherosclerosis. In this review, we summarize the knowledge that CL is involved in the pathogenesis of atherosclerosis. On the one hand, CL and its oxidative modification promote the progression of atherosclerosis via several mechanisms, including oxidative stress, apoptosis, and inflammation in response to stress. On the other hand, CL externalizes to the outer mitochondrial membrane (OMM) and acts as the pivotal "eat-me" signal in mitophagy, removing dysfunctional mitochondria and safeguarding against the progression of atherosclerosis. Given the imbalance between proatherogenic and antiatherogenic effects, we provide our understanding of the roles of the CL and its oxidative modification in atherosclerotic cardiovascular diseases, in addition to potential therapeutic strategies aimed at restoring the CL. Briefly, CL is far more than a structural IMM lipid; broader significances of the evolutionarily conserved lipid need to be explored.
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Affiliation(s)
- Jin Wei
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Meng Zhang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xia Wang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Kaiying Yang
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Qi Xiao
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China.
| | - Xiaoyan Zhu
- Department of Critical Care Medicine, The Affiliated Hospital of Qingdao University, Qingdao, China.
| | - Xudong Pan
- Department of Neurology, The Affiliated Hospital of Qingdao University, Qingdao, China.
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2
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Beigl TB, Paul A, Fellmeth TP, Nguyen D, Barber L, Weller S, Schäfer B, Gillissen BF, Aulitzky WE, Kopp HG, Rehm M, Andrews DW, Pluhackova K, Essmann F. BCL-2 and BOK regulate apoptosis by interaction of their C-terminal transmembrane domains. EMBO Rep 2024; 25:3896-3924. [PMID: 39048751 PMCID: PMC11387410 DOI: 10.1038/s44319-024-00206-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 06/17/2024] [Accepted: 06/25/2024] [Indexed: 07/27/2024] Open
Abstract
The Bcl-2 family controls apoptosis by direct interactions of pro- and anti-apoptotic proteins. The principle mechanism is binding of the BH3 domain of pro-apoptotic proteins to the hydrophobic groove of anti-apoptotic siblings, which is therapeutically exploited by approved BH3-mimetic anti-cancer drugs. Evidence suggests that also the transmembrane domain (TMD) of Bcl-2 proteins can mediate Bcl-2 interactions. We developed a highly-specific split luciferase assay enabling the analysis of TMD interactions of pore-forming apoptosis effectors BAX, BAK, and BOK with anti-apoptotic Bcl-2 proteins in living cells. We confirm homotypic interaction of the BAX-TMD, but also newly identify interaction of the TMD of anti-apoptotic BCL-2 with the TMD of BOK, a peculiar pro-apoptotic Bcl-2 protein. BOK-TMD and BCL-2-TMD interact at the endoplasmic reticulum. Molecular dynamics simulations confirm dynamic BOK-TMD and BCL-2-TMD dimers and stable heterotetramers. Mutation of BCL-2-TMD at predicted key residues abolishes interaction with BOK-TMD. Also, inhibition of BOK-induced apoptosis by BCL-2 depends specifically on their TMDs. Thus, TMDs of Bcl-2 proteins are a relevant interaction interface for apoptosis regulation and provide a novel potential drug target.
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Affiliation(s)
- Tobias B Beigl
- Robert Bosch Center for Tumor Diseases, Stuttgart, Germany
| | - Alexander Paul
- Robert Bosch Center for Tumor Diseases, Stuttgart, Germany
| | - Thomas P Fellmeth
- Cluster of Excellence SimTech, University of Stuttgart, Stuttgart, Germany
| | - Dang Nguyen
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Canada
- Biological Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
| | - Lynn Barber
- Robert Bosch Center for Tumor Diseases, Stuttgart, Germany
| | - Sandra Weller
- Robert Bosch Center for Tumor Diseases, Stuttgart, Germany
| | | | - Bernhard F Gillissen
- Department of Hematology, Oncology, and Tumorimmunology, Charité University Medicine, Berlin, Germany
| | | | - Hans-Georg Kopp
- Robert Bosch Center for Tumor Diseases, Stuttgart, Germany
- Robert-Bosch-Hospital, Stuttgart, Germany
| | - Markus Rehm
- Institute of Cell Biology and Immunology, University of Stuttgart, Stuttgart, Germany
- Stuttgart Research Center Systems Biology, University of Stuttgart, Stuttgart, Germany
| | - David W Andrews
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Canada
- Biological Sciences Platform, Sunnybrook Research Institute, Toronto, Canada
- Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, Canada
| | | | - Frank Essmann
- Robert Bosch Center for Tumor Diseases, Stuttgart, Germany.
- Department of Molecular Medicine, Interfaculty Institute for Biochemistry, Eberhard Karls University Tübingen, Tübingen, Germany.
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3
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Vassallo N. Poration of mitochondrial membranes by amyloidogenic peptides and other biological toxins. J Neurochem 2024. [PMID: 39213385 DOI: 10.1111/jnc.16213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 08/09/2024] [Accepted: 08/12/2024] [Indexed: 09/04/2024]
Abstract
Mitochondria are essential organelles known to serve broad functions, including in cellular metabolism, calcium buffering, signaling pathways and the regulation of apoptotic cell death. Maintaining the integrity of the outer (OMM) and inner mitochondrial membranes (IMM) is vital for mitochondrial health. Cardiolipin (CL), a unique dimeric glycerophospholipid, is the signature lipid of energy-converting membranes. It plays a significant role in maintaining mitochondrial architecture and function, stabilizing protein complexes and facilitating efficient oxidative phosphorylation (OXPHOS) whilst regulating cytochrome c release from mitochondria. CL is especially enriched in the IMM and at sites of contact between the OMM and IMM. Disorders of protein misfolding, such as Alzheimer's and Parkinson's diseases, involve amyloidogenic peptides like amyloid-β, tau and α-synuclein, which form metastable toxic oligomeric species that interact with biological membranes. Electrophysiological studies have shown that these oligomers form ion-conducting nanopores in membranes mimicking the IMM's phospholipid composition. Poration of mitochondrial membranes disrupts the ionic balance, causing osmotic swelling, loss of the voltage potential across the IMM, release of pro-apoptogenic factors, and leads to cell death. The interaction between CL and amyloid oligomers appears to favour their membrane insertion and pore formation, directly implicating CL in amyloid toxicity. Additionally, pore formation in mitochondrial membranes is not limited to amyloid proteins and peptides; other biological peptides, as diverse as the pro-apoptotic Bcl-2 family members, gasdermin proteins, cobra venom cardiotoxins and bacterial pathogenic toxins, have all been described to punch holes in mitochondria, contributing to cell death processes. Collectively, these findings underscore the vulnerability of mitochondria and the involvement of CL in various pathogenic mechanisms, emphasizing the need for further research on targeting CL-amyloid interactions to mitigate mitochondrial dysfunction.
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Affiliation(s)
- Neville Vassallo
- Department of Physiology and Biochemistry, Faculty of Medicine and Surgery, University of Malta, Tal-Qroqq, Malta
- Centre for Molecular Medicine and Biobanking, University of Malta, Tal-Qroqq, Malta
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4
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Dadsena S, Cuevas Arenas R, Vieira G, Brodesser S, Melo MN, García-Sáez AJ. Lipid unsaturation promotes BAX and BAK pore activity during apoptosis. Nat Commun 2024; 15:4700. [PMID: 38830851 PMCID: PMC11148036 DOI: 10.1038/s41467-024-49067-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 05/22/2024] [Indexed: 06/05/2024] Open
Abstract
BAX and BAK are proapoptotic members of the BCL2 family that directly mediate mitochondrial outer membrane permeabilition (MOMP), a central step in apoptosis execution. However, the molecular architecture of the mitochondrial apoptotic pore remains a key open question and especially little is known about the contribution of lipids to MOMP. By performing a comparative lipidomics analysis of the proximal membrane environment of BAK isolated in lipid nanodiscs, we find a significant enrichment of unsaturated species nearby BAK and BAX in apoptotic conditions. We then demonstrate that unsaturated lipids promote BAX pore activity in model membranes, isolated mitochondria and cellular systems, which is further supported by molecular dynamics simulations. Accordingly, the fatty acid desaturase FADS2 not only enhances apoptosis sensitivity, but also the activation of the cGAS/STING pathway downstream mtDNA release. The correlation of FADS2 levels with the sensitization to apoptosis of different lung and kidney cancer cell lines by co-treatment with unsaturated fatty acids supports the relevance of our findings. Altogether, our work provides an insight on how local lipid environment affects BAX and BAK function during apoptosis.
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Affiliation(s)
- Shashank Dadsena
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Rodrigo Cuevas Arenas
- Structural Biochemistry, Bijvoet Center for Biomolecular Research, Utrecht University, 3584CG, Utrecht, The Netherlands
| | - Gonçalo Vieira
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Susanne Brodesser
- Cluster of Excellence Cellular Stress Responses in Aging-associated Diseases (CECAD), Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, Germany
| | - Manuel N Melo
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany.
- Department of Membrane Dynamics, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
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5
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Tang Y, Wu J, Sun X, Tan S, Li W, Yin S, Liu L, Chen Y, Liu Y, Tan Q, Jiang Y, Yang W, Huang W, Weng C, Wu Q, Lu Y, Yuan H, Xiao Q, Chen AF, Xu Q, Billiar TR, Cai J. Cardiolipin oxidized by ROS from complex II acts as a target of gasdermin D to drive mitochondrial pore and heart dysfunction in endotoxemia. Cell Rep 2024; 43:114237. [PMID: 38753484 DOI: 10.1016/j.celrep.2024.114237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 04/16/2024] [Accepted: 04/30/2024] [Indexed: 05/18/2024] Open
Abstract
Cardiac dysfunction, an early complication of endotoxemia, is the major cause of death in intensive care units. No specific therapy is available at present for this cardiac dysfunction. Here, we show that the N-terminal gasdermin D (GSDMD-N) initiates mitochondrial apoptotic pore and cardiac dysfunction by directly interacting with cardiolipin oxidized by complex II-generated reactive oxygen species (ROS) during endotoxemia. Caspase-4/11 initiates GSDMD-N pores that are subsequently amplified by the upregulation and activation of NLRP3 inflammation through further generation of ROS. GSDMD-N pores form prior to BAX and VDAC1 apoptotic pores and further incorporate into BAX and VDAC1 oligomers within mitochondria membranes to exacerbate the apoptotic process. Our findings identify oxidized cardiolipin as the definitive target of GSDMD-N in mitochondria of cardiomyocytes during endotoxin-induced myocardial dysfunction (EIMD), and modulation of cardiolipin oxidation could be a therapeutic target early in the disease process to prevent EIMD.
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Affiliation(s)
- Yan Tang
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China; Department of Cardiology, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang 330006, China
| | - Junru Wu
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Xuejing Sun
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Shasha Tan
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Wenbo Li
- Department of Plastic and Aesthetic (Burn) Surgery, the Second Xiangya Hospital, Central South University, Changsha 410000, China
| | - Siyu Yin
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Lun Liu
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Yuanyuan Chen
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Yuanyuan Liu
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Qian Tan
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Youxiang Jiang
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Wenjing Yang
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Wei Huang
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Chunyan Weng
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Qing Wu
- Center for High-Performance Computing, Central South University, Changsha 410000, China
| | - Yao Lu
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Hong Yuan
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Qingzhong Xiao
- Centre for Clinical Pharmacology, William Harvey Research Institute, Barts, and The London School of Medicine and Dentistry, Queen Mary University of London, EC1M 6BQ London, UK
| | - Alex F Chen
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China; Department of Cardiology, Institute for Cardiovascular Development and Regenerative Medicine, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 200092 Shanghai, China
| | - Qingbo Xu
- Department of Cardiology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Timothy R Billiar
- Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
| | - Jingjing Cai
- Clinical Research Center, Department of Cardiology, the Third Xiangya Hospital, Central South University, Changsha 410013, China.
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6
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Jenner A, Garcia-Saez AJ. The regulation of the apoptotic pore-An immunological tightrope walk. Adv Immunol 2024; 162:59-108. [PMID: 38866439 DOI: 10.1016/bs.ai.2024.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024]
Abstract
Apoptotic pore formation in mitochondria is the pivotal point for cell death during mitochondrial apoptosis. It is regulated by BCL-2 family proteins in response to various cellular stress triggers and mediates mitochondrial outer membrane permeabilization (MOMP). This allows the release of mitochondrial contents into the cytosol, which triggers rapid cell death and clearance through the activation of caspases. However, under conditions of low caspase activity, the mitochondrial contents released into the cytosol through apoptotic pores serve as inflammatory signals and activate various inflammatory responses. In this chapter, we discuss how the formation of the apoptotic pore is regulated by BCL-2 proteins as well as other cellular or mitochondrial proteins and membrane lipids. Moreover, we highlight the importance of sublethal MOMP in the regulation of mitochondrial-activated inflammation and discuss its physiological consequences in the context of pathogen infection and disease and how it can potentially be exploited therapeutically, for example to improve cancer treatment.
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Affiliation(s)
- Andreas Jenner
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Ana J Garcia-Saez
- Institute for Genetics and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
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7
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Lin Z, Long F, Kang R, Klionsky DJ, Yang M, Tang D. The lipid basis of cell death and autophagy. Autophagy 2024; 20:469-488. [PMID: 37768124 PMCID: PMC10936693 DOI: 10.1080/15548627.2023.2259732] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
ABBREVIATIONS ACSL: acyl-CoA synthetase long chain family; DISC: death-inducing signaling complex; DAMPs: danger/damage-associated molecular patterns; Dtgn: dispersed trans-Golgi network; FAR1: fatty acyl-CoA reductase 1; GPX4: glutathione peroxidase 4; LPCAT3: lysophosphatidylcholine acyltransferase 3; LPS: lipopolysaccharide; MUFAs: monounsaturated fatty acids; MOMP: mitochondrial outer membrane permeabilization; MLKL, mixed lineage kinase domain like pseudokinase; oxPAPC: oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine; OxPCs: oxidized phosphatidylcholines; PUFAs: polyunsaturated fatty acids; POR: cytochrome p450 oxidoreductase; PUFAs: polyunsaturated fatty acids; RCD: regulated cell death; RIPK1: receptor interacting serine/threonine kinase 1; SPHK1: sphingosine kinase 1; SOAT1: sterol O-acyltransferase 1; SCP2: sterol carrier protein 2; SFAs: saturated fatty acids; SLC47A1: solute carrier family 47 member 1; SCD: stearoyl-CoA desaturase; VLCFA: very long chain fatty acids.
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Affiliation(s)
- Zhi Lin
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Clinical Research Center of Pediatric Cancer, Changsha, Hunan, China
| | - Fei Long
- Department of Gastrointestinal Surgery, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
- Postdoctoral Research Station of Basic Medicine, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Rui Kang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
| | - Daniel J. Klionsky
- Life Sciences Institute and Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Minghua Yang
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
- Hunan Clinical Research Center of Pediatric Cancer, Changsha, Hunan, China
| | - Daolin Tang
- Department of Surgery, UT Southwestern Medical Center, Dallas, TX, USA
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8
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King LE, Hohorst L, García-Sáez AJ. Expanding roles of BCL-2 proteins in apoptosis execution and beyond. J Cell Sci 2023; 136:jcs260790. [PMID: 37994778 DOI: 10.1242/jcs.260790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2023] Open
Abstract
The proteins of the BCL-2 family are known as key regulators of apoptosis, with interactions between family members determining permeabilisation of the mitochondrial outer membrane (MOM) and subsequent cell death. However, the exact mechanism through which they form the apoptotic pore responsible for MOM permeabilisation (MOMP), the structure and specific components of this pore, and what roles BCL-2 proteins play outside of directly regulating MOMP are incompletely understood. Owing to the link between apoptosis dysregulation and disease, the BCL-2 proteins are important targets for drug development. With the development and clinical use of drugs targeting BCL-2 proteins showing success in multiple haematological malignancies, enhancing the efficacy of these drugs, or indeed developing novel drugs targeting BCL-2 proteins is of great interest to treat cancer patients who have developed resistance or who suffer other disease types. Here, we review our current understanding of the molecular mechanism of MOMP, with a particular focus on recently discovered roles of BCL-2 proteins in apoptosis and beyond, and discuss what implications these functions might have in both healthy tissues and disease.
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Affiliation(s)
- Louise E King
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne 50931, Germany
| | - Lisa Hohorst
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne 50931, Germany
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne 50931, Germany
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9
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Czabotar PE, Garcia-Saez AJ. Mechanisms of BCL-2 family proteins in mitochondrial apoptosis. Nat Rev Mol Cell Biol 2023; 24:732-748. [PMID: 37438560 DOI: 10.1038/s41580-023-00629-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 81.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/14/2023]
Abstract
The proteins of the BCL-2 family are key regulators of mitochondrial apoptosis, acting as either promoters or inhibitors of cell death. The functional interplay and balance between the opposing BCL-2 family members control permeabilization of the outer mitochondrial membrane, leading to the release of activators of the caspase cascade into the cytosol and ultimately resulting in cell death. Despite considerable research, our knowledge about the mechanisms of the BCL-2 family of proteins remains insufficient, which complicates cell fate predictions and does not allow us to fully exploit these proteins as targets for drug discovery. Detailed understanding of the formation and molecular architecture of the apoptotic pore in the outer mitochondrial membrane remains a holy grail in the field, but new studies allow us to begin constructing a structural model of its arrangement. Recent literature has also revealed unexpected activities for several BCL-2 family members that challenge established concepts of how they regulate mitochondrial permeabilization. In this Review, we revisit the most important advances in the field and integrate them into a new structure-function-based classification of the BCL-2 family members that intends to provide a comprehensive model for BCL-2 action in apoptosis. We close this Review by discussing the potential of drugging the BCL-2 family in diseases characterized by aberrant apoptosis.
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Affiliation(s)
- Peter E Czabotar
- The Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia.
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia.
| | - Ana J Garcia-Saez
- Membrane Biophysics, Institute of Genetics, CECAD, University of Cologne, Cologne, Germany.
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10
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Clifton LA, Wacklin-Knecht HP, Ådén J, Mushtaq AU, Sparrman T, Gröbner G. Creation of distinctive Bax-lipid complexes at mitochondrial membrane surfaces drives pore formation to initiate apoptosis. SCIENCE ADVANCES 2023; 9:eadg7940. [PMID: 37267355 PMCID: PMC10413641 DOI: 10.1126/sciadv.adg7940] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/04/2023]
Abstract
Apotosis is an essential process tightly regulated by the Bcl-2 protein family where proapoptotic Bax triggers cell death by perforating the mitochondrial outer membrane. Although intensively studied, the molecular mechanism by which these proteins create apoptotic pores remains elusive. Here, we show that Bax creates pores by extracting lipids from outer mitochondrial membrane mimics by formation of Bax/lipid clusters that are deposited on the membrane surface. Time-resolved neutron reflectometry and Fourier transform infrared spectroscopy revealed two kinetically distinct phases in the pore formation process, both of which were critically dependent on cardiolipin levels. The initially fast adsorption of Bax on the mitochondrial membrane surface is followed by a slower formation of pores and Bax-lipid clusters on the membrane surface. Our findings provide a robust molecular understanding of mitochondrial membrane perforation by cell-killing Bax protein and illuminate the initial phases of programmed cellular death.
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Affiliation(s)
- Luke A. Clifton
- ISIS Pulsed Neutron and Muon Source, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 OQX, UK
| | - Hanna P. Wacklin-Knecht
- European Spallation Source ERIC, ESS, P.O. Box 176, SE-22100 Lund, Sweden
- Department of Chemistry, Division of Physical Chemistry, Lund University, P.O. Box 124, SE-22100 Lund, Sweden
| | - Jörgen Ådén
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
| | - Ameeq Ul Mushtaq
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
| | - Tobias Sparrman
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
| | - Gerhard Gröbner
- Department of Chemistry, University of Umeå, SE-90187 Umeå, Sweden
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11
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Flores-Romero H, Dadsena S, García-Sáez AJ. Mitochondrial pores at the crossroad between cell death and inflammatory signaling. Mol Cell 2023; 83:843-856. [PMID: 36931255 DOI: 10.1016/j.molcel.2023.02.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/13/2023] [Accepted: 02/16/2023] [Indexed: 03/18/2023]
Abstract
Mitochondria are cellular organelles with a major role in many cellular processes, including not only energy production, metabolism, and calcium homeostasis but also regulated cell death and innate immunity. Their proteobacterial origin makes them a rich source of potent immune agonists, normally hidden within the mitochondrial membrane barriers. Alteration of mitochondrial permeability through mitochondrial pores thus provides efficient mechanisms not only to communicate mitochondrial stress to the cell but also as a key event in the integration of cellular responses. In this regard, eukaryotic cells have developed diverse signaling networks that sense and respond to the release of mitochondrial components into the cytosol and play a key role in controlling cell death and inflammatory pathways. Modulating pore formation at mitochondria through direct or indirect mechanisms may thus open new opportunities for therapy. In this review, we discuss the current understanding of the structure and molecular mechanisms of mitochondrial pores and how they function at the interface between cell death and inflammatory signaling to regulate cellular outcomes.
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Affiliation(s)
- Hector Flores-Romero
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Shashank Dadsena
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany
| | - Ana J García-Sáez
- Institute for Genetics, CECAD Research Center, University of Cologne, Cologne, Germany.
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12
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Moldoveanu T. Apoptotic mitochondrial poration by a growing list of pore-forming BCL-2 family proteins. Bioessays 2023; 45:e2200221. [PMID: 36650950 PMCID: PMC9975053 DOI: 10.1002/bies.202200221] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/31/2022] [Accepted: 01/02/2023] [Indexed: 01/19/2023]
Abstract
The pore-forming BCL-2 family proteins are effectors of mitochondrial poration in apoptosis initiation. Two atypical effectors-BOK and truncated BID (tBID)-join the canonical effectors BAK and BAX. Gene knockout revealed developmental phenotypes in the absence the effectors, supporting their roles in vivo. During apoptosis effectors are activated and change shape from dormant monomers to dynamic oligomers that associate with and permeabilize mitochondria. BID is activated by proteolysis, BOK accumulates on inhibition of its degradation by the E3 ligase gp78, while BAK and BAX undergo direct activation by BH3-only initiators, autoactivation, and crossactivation. Except tBID, effector oligomers on the mitochondria appear as arcs and rings in super-resolution microscopy images. The BH3-in-groove dimers of BAK and BAX, the tBID monomers, and uncharacterized BOK species are the putative building blocks of apoptotic pores. Effectors interact with lipids and bilayers but the mechanism of membrane poration remains elusive. I discuss effector-mediated mitochondrial poration.
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Affiliation(s)
- Tudor Moldoveanu
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences,Correspondence:
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13
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Margheritis E, Kappelhoff S, Cosentino K. Pore-Forming Proteins: From Pore Assembly to Structure by Quantitative Single-Molecule Imaging. Int J Mol Sci 2023; 24:ijms24054528. [PMID: 36901959 PMCID: PMC10003378 DOI: 10.3390/ijms24054528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/11/2023] [Accepted: 02/21/2023] [Indexed: 03/03/2023] Open
Abstract
Pore-forming proteins (PFPs) play a central role in many biological processes related to infection, immunity, cancer, and neurodegeneration. A common feature of PFPs is their ability to form pores that disrupt the membrane permeability barrier and ion homeostasis and generally induce cell death. Some PFPs are part of the genetically encoded machinery of eukaryotic cells that are activated against infection by pathogens or in physiological programs to carry out regulated cell death. PFPs organize into supramolecular transmembrane complexes that perforate membranes through a multistep process involving membrane insertion, protein oligomerization, and finally pore formation. However, the exact mechanism of pore formation varies from PFP to PFP, resulting in different pore structures with different functionalities. Here, we review recent insights into the molecular mechanisms by which PFPs permeabilize membranes and recent methodological advances in their characterization in artificial and cellular membranes. In particular, we focus on single-molecule imaging techniques as powerful tools to unravel the molecular mechanistic details of pore assembly that are often obscured by ensemble measurements, and to determine pore structure and functionality. Uncovering the mechanistic elements of pore formation is critical for understanding the physiological role of PFPs and developing therapeutic approaches.
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14
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Vringer E, Tait SWG. Mitochondria and cell death-associated inflammation. Cell Death Differ 2023; 30:304-312. [PMID: 36447047 PMCID: PMC9950460 DOI: 10.1038/s41418-022-01094-w] [Citation(s) in RCA: 82] [Impact Index Per Article: 82.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/17/2022] [Accepted: 11/11/2022] [Indexed: 12/03/2022] Open
Abstract
Mitochondria have recently emerged as key drivers of inflammation associated with cell death. Many of the pro-inflammatory pathways activated during cell death occur upon mitochondrial outer membrane permeabilization (MOMP), the pivotal commitment point to cell death during mitochondrial apoptosis. Permeabilised mitochondria trigger inflammation, in part, through the release of mitochondrial-derived damage-associated molecular patterns (DAMPs). Caspases, while dispensable for cell death during mitochondrial apoptosis, inhibit activation of pro-inflammatory pathways after MOMP. Some of these mitochondrial-activated inflammatory pathways can be traced back to the bacterial ancestry of mitochondria. For instance, mtDNA and bacterial DNA are highly similar thereby activating similar cell autonomous immune signalling pathways. The bacterial origin of mitochondria suggests that inflammatory pathways found in cytosol-invading bacteria may be relevant to mitochondrial-driven inflammation after MOMP. In this review, we discuss how mitochondria can initiate inflammation during cell death highlighting parallels with bacterial activation of inflammation. Moreover, we discuss the roles of mitochondrial inflammation during cell death and how these processes may potentially be harnessed therapeutically, for instance to improve cancer treatment.
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Affiliation(s)
- Esmee Vringer
- Cancer Research UK Beatson Institute, Glasgow, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
| | - Stephen W G Tait
- Cancer Research UK Beatson Institute, Glasgow, UK.
- Institute of Cancer Sciences, University of Glasgow, Glasgow, UK.
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15
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Pore-forming proteins as drivers of membrane permeabilization in cell death pathways. Nat Rev Mol Cell Biol 2022; 24:312-333. [PMID: 36543934 DOI: 10.1038/s41580-022-00564-w] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/08/2022] [Indexed: 12/24/2022]
Abstract
Regulated cell death (RCD) relies on activation and recruitment of pore-forming proteins (PFPs) that function as executioners of specific cell death pathways: apoptosis regulator BAX (BAX), BCL-2 homologous antagonist/killer (BAK) and BCL-2-related ovarian killer protein (BOK) for apoptosis, gasdermins (GSDMs) for pyroptosis and mixed lineage kinase domain-like protein (MLKL) for necroptosis. Inactive precursors of PFPs are converted into pore-forming entities through activation, membrane recruitment, membrane insertion and oligomerization. These mechanisms involve protein-protein and protein-lipid interactions, proteolytic processing and phosphorylation. In this Review, we discuss the structural rearrangements incurred by RCD-related PFPs and describe the mechanisms that manifest conversion from autoinhibited to membrane-embedded molecular states. We further discuss the formation and maturation of membrane pores formed by BAX/BAK/BOK, GSDMs and MLKL, leading to diverse pore architectures. Lastly, we highlight commonalities and differences of PFP mechanisms involving BAX/BAK/BOK, GSDMs and MLKL and conclude with a discussion on how, in a population of challenged cells, the coexistence of cell death modalities may have profound physiological and pathophysiological implications.
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16
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Chen L, Dong J, Liao S, Wang S, Wu Z, Zuo M, Liu B, Yan C, Chen Y, He H, Meng Q, Song Z. Loss of Sam50 in hepatocytes induces cardiolipin-dependent mitochondrial membrane remodeling to trigger mtDNA release and liver injury. Hepatology 2022; 76:1389-1408. [PMID: 35313046 DOI: 10.1002/hep.32471] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND AIMS Sam50, a key component of the sorting and assembly machinery (SAM) complex, is also involved in bridging mitochondrial outer-membrane and inner-membrane contacts. However, the physiological and pathological functions of Sam50 remain largely unknown. APPROACH AND RESULTS Here we show that Sam50 interacts with MICOS (mitochondrial contact site and cristae organizing system) and ATAD3 (ATPase family AAA domain-containing protein 3) to form the Sam50-MICOS-ATAD3-mtDNA axis, which maintains mtDNA stability. Loss of Sam50 causes mitochondrial DNA (mtDNA) aggregation. Furthermore, Sam50 cooperates with Mic60 to bind to cardiolipin, maintaining the integrity of mitochondrial membranes. Sam50 depletion leads to cardiolipin externalization, which causes mitochondrial outer-membrane and inner-membrane (including crista membrane) remodeling, triggering Bax mitochondrial recruitment, mtDNA aggregation, and release. Physiologically, acetaminophen (an effective antipyretic and analgesic)-caused Sam50 reduction or Sam50 liver-specific knockout induces mtDNA release, leading to activation of the cGAS-STING pathway and liver inflammation in mice. Moreover, exogenous expression of Sam50 remarkably attenuates APAP-induced liver hepatoxicity. CONCLUSIONS Our findings uncover the critical role of Sam50 in maintaining mitochondrial membrane integrity and mtDNA stability in hepatocytes and reveal that Sam50 depletion-induced cardiolipin externalization is a signal of mtDNA release and controls mtDNA-dependent innate immunity.
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Affiliation(s)
- Li Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Jun Dong
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Siyang Liao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Siyou Wang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Zhida Wu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Meiling Zuo
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Bing Liu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Chaojun Yan
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Yong Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - He He
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Qingtao Meng
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
| | - Zhiyin Song
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Frontier Science Center for Immunology and Metabolism, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, Hubei, China
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17
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Smith NA, Wardak AZ, Cowan AD, Colman PM, Czabotar PE, Smith BJ. The Bak core dimer focuses triacylglycerides in the membrane. Biophys J 2022; 121:347-360. [PMID: 34973947 PMCID: PMC8822611 DOI: 10.1016/j.bpj.2021.12.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/15/2021] [Accepted: 12/28/2021] [Indexed: 02/03/2023] Open
Abstract
Apoptosis, the intrinsic programmed cell death process, is mediated by the Bcl-2 family members Bak and Bax. Activation via formation of symmetric core dimers and oligomerization on the mitochondrial outer membrane (MOM) leads to permeabilization and cell death. Although this process is linked to the MOM, the role of the membrane in facilitating such pores is poorly understood. We recently described Bak core domain dimers, revealing lipid binding sites and an initial role of lipids in oligomerization. Here we describe simulations that identified localized clustering and interaction of triacylglycerides (TAGs) with a minimized Bak dimer construct. Coalescence of TAGs occurred beneath this Bak dimer, mitigating dimer-induced local membrane thinning and curvature in representative coarse-grain MOM and model membrane systems. Furthermore, the effects observed as a result of coarse-grain TAG cluster formation was concentration dependent, scaling from low physiological MOM concentrations to those found in other organelles. We find that increasing the TAG concentration in liposomes mimicking the MOM decreased the ability of activated Bak to permeabilize these liposomes. These results suggest that the presence of TAGs within a Bak-lipid membrane preserves membrane integrity and is associated with reduced membrane stress, suggesting a possible role of TAGs in Bak-mediated apoptosis.
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Affiliation(s)
- Nicholas A. Smith
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia
| | - Ahmad Z. Wardak
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Angus D. Cowan
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Peter M. Colman
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Peter E. Czabotar
- Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia,Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Brian J. Smith
- La Trobe Institute for Molecular Science, La Trobe University, Bundoora, Victoria, Australia,Corresponding author
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18
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Sperl LE, Rührnößl F, Schiller A, Haslbeck M, Hagn F. High-resolution analysis of the conformational transition of pro-apoptotic Bak at the lipid membrane. EMBO J 2021; 40:e107159. [PMID: 34523144 PMCID: PMC8521305 DOI: 10.15252/embj.2020107159] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 08/09/2021] [Accepted: 08/20/2021] [Indexed: 12/21/2022] Open
Abstract
Permeabilization of the outer mitochondrial membrane by pore-forming Bcl2 proteins is a crucial step for the induction of apoptosis. Despite a large set of data suggesting global conformational changes within pro-apoptotic Bak during pore formation, high-resolution structural details in a membrane environment remain sparse. Here, we used NMR and HDX-MS (Hydrogen deuterium exchange mass spectrometry) in lipid nanodiscs to gain important high-resolution structural insights into the conformational changes of Bak at the membrane that are dependent on a direct activation by BH3-only proteins. Furthermore, we determined the first high-resolution structure of the Bak transmembrane helix. Upon activation, α-helix 1 in the soluble domain of Bak dissociates from the protein and adopts an unfolded and dynamic potentially membrane-bound state. In line with this finding, comparative protein folding experiments with Bak and anti-apoptotic BclxL suggest that α-helix 1 in Bak is a metastable structural element contributing to its pro-apoptotic features. Consequently, mutagenesis experiments aimed at stabilizing α-helix 1 yielded Bak variants with delayed pore-forming activity. These insights will contribute to a better mechanistic understanding of Bak-mediated membrane permeabilization.
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Affiliation(s)
- Laura E Sperl
- Bavarian NMR Center at the Department of ChemistryTechnical University of MunichGarchingGermany
- Institute of Structural BiologyHelmholtz Zentrum MünchenNeuherbergGermany
| | - Florian Rührnößl
- Center for Functional Protein Assemblies and Department of ChemistryTechnical University of MunichGarchingGermany
| | - Anita Schiller
- Bavarian NMR Center at the Department of ChemistryTechnical University of MunichGarchingGermany
- Institute of Structural BiologyHelmholtz Zentrum MünchenNeuherbergGermany
| | - Martin Haslbeck
- Center for Functional Protein Assemblies and Department of ChemistryTechnical University of MunichGarchingGermany
| | - Franz Hagn
- Bavarian NMR Center at the Department of ChemistryTechnical University of MunichGarchingGermany
- Institute of Structural BiologyHelmholtz Zentrum MünchenNeuherbergGermany
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19
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Rose M, Kurylowicz M, Mahmood M, Winkel S, Moran-Mirabal JM, Fradin C. Direct Measurement of the Affinity between tBid and Bax in a Mitochondria-Like Membrane. Int J Mol Sci 2021; 22:8240. [PMID: 34361006 PMCID: PMC8348223 DOI: 10.3390/ijms22158240] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/19/2021] [Accepted: 07/22/2021] [Indexed: 01/05/2023] Open
Abstract
The execution step in apoptosis is the permeabilization of the outer mitochondrial membrane, controlled by Bcl-2 family proteins. The physical interactions between the different proteins in this family and their relative abundance literally determine the fate of the cells. These interactions, however, are difficult to quantify, as they occur in a lipid membrane and involve proteins with multiple conformations and stoichiometries which can exist both in soluble and membrane. Here we focus on the interaction between two core Bcl-2 family members, the executor pore-forming protein Bax and the truncated form of the activator protein Bid (tBid), which we imaged at the single particle level in a mitochondria-like planar supported lipid bilayer. We inferred the conformation of the proteins from their mobility, and detected their transient interactions using a novel single particle cross-correlation analysis. We show that both tBid and Bax have at least two different conformations at the membrane, and that their affinity for one another increases by one order of magnitude (with a 2D-KD decreasing from ≃1.6μm-2 to ≃0.1μm-2) when they pass from their loosely membrane-associated to their transmembrane form. We conclude by proposing an updated molecular model for the activation of Bax by tBid.
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Affiliation(s)
- Markus Rose
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Martin Kurylowicz
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Mohammad Mahmood
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Sheldon Winkel
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
| | - Jose M. Moran-Mirabal
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada;
| | - Cécile Fradin
- Department of Physics and Astronomy, McMaster University, Hamilton, ON L8S 4M1, Canada; (M.R.); (M.K.); (M.M.); (S.W.)
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
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20
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Su J, Liao D, Su Y, Liu S, Jiang L, Wu J, Liu Z, Wu Y. Novel polysaccharide extracted from Sipunculus nudus inhibits HepG2 tumour growth in vivo by enhancing immune function and inducing tumour cell apoptosis. J Cell Mol Med 2021; 25:8338-8351. [PMID: 34302428 PMCID: PMC8419178 DOI: 10.1111/jcmm.16793] [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: 04/26/2021] [Revised: 07/01/2021] [Accepted: 07/05/2021] [Indexed: 01/23/2023] Open
Abstract
A novel polysaccharide was extracted from Sipunculus nudus (SNP). The molecular weight (MW) of SNP was determined to be 9223 Da by high‐performance gel permeation chromatography analyses, and the structure of the SNP repeat units was determined to be →3,4‐β‐D‐GlcpNAC (1→ and →4) ‐α‐D‐Glcp (1→ in the ratio of 15:1; →2) ‐α ‐D‐Galp ‐ (1→ as a side chain; and β‐D‐Galp‐(1→ and α‐ D‐Glcp ‐ (1→ as end groups by GC‐MS analysis and NMR assays. The effect of SNP on hepatoma HepG2‐bearing mice was analysed to verify its potential in the clinical treatment of liver cancer. A total of 90 male athymic nu/nu mice were divided into therapeutic and preventive groups and fed with different amounts of SNP. The antitumour effect of SNP on HepG2‐bearing mice and mechanism of such were studied by analysing the tumour size, spleen index, thymus index, immune factors in the blood, tumour apoptosis factors, etc. The results suggest that SNP not only increased the index of immune organs in the body, but also enhanced the secretion of immune factors, including interleukin‐2, interferon gamma and tumour necrosis factor‐alpha in the serum. SNP induced the apoptosis of tumour cells via the mitochondrial apoptosis pathway, which upregulated caspase‐3, caspase‐8, caspase‐9 and BCL2‐associated X, but downregulated B‐cell lymphoma‐2 and vascular endothelial growth factor protein expression. In conclusion, SNP inhibited tumour growth by enhancing immune function and inducing tumour cell apoptosis in HepG2‐bearing mice. Therefore, SNP may be further investigated as a promising candidate for future antitumour drugs.
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Affiliation(s)
- Jie Su
- Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, China
| | - Dengyuan Liao
- Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, China
| | - Yongchang Su
- Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, China
| | - Shuji Liu
- Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, China
| | - Linlin Jiang
- Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, China
| | - Jingna Wu
- Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, China
| | - Zhiyu Liu
- Key Laboratory of Cultivation and High-value Utilization of Marine Organisms in Fujian Province, Fisheries Research Institute of Fujian, Xiamen, China
| | - Yuping Wu
- Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, Zhuhai Key Laboratory of Marine Bioresources and Environment, School of Marine Sciences, Sun Yat-Sen University, Guangzhou, China
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21
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Hung CL, Chang HH, Lee SW, Chiang YW. Stepwise activation of the pro-apoptotic protein Bid at mitochondrial membranes. Cell Death Differ 2021; 28:1910-1925. [PMID: 33462413 PMCID: PMC8184993 DOI: 10.1038/s41418-020-00716-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 12/01/2020] [Accepted: 12/16/2020] [Indexed: 01/30/2023] Open
Abstract
Caspase-8-cleaved Bid (cBid) associates with mitochondria and promotes the activation of BAX, leading to mitochondria outer membrane permeabilization (MOMP) and apoptosis. However, current structural models of cBid are largely based on studies using membrane vesicles and detergent micelles. Here we employ spin-label ESR and site-directed PEGylation methods to identify conformations of cBid at real mitochondrial membranes, revealing stepwise mechanisms in the activation process. Upon the binding of cBid to mitochondria, its structure is reorganized to expose the BH3 domain while leaving the structural integrity only slightly altered. The mitochondria-bound cBid is in association with Mtch2 and it remains in the primed state until interacting with BAX. The interaction subsequently triggers the fragmentation of cBid, causes large conformational changes, and promotes BAX-mediated MOMP. Our results reveal structural differences of cBid between mitochondria and other lipid-like environments and, moreover, highlight the role of the membrane binding in modifying cBid structure and assisting the inactive-to-active transition in function.
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Affiliation(s)
- Chien-Lun Hung
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Hsin-Ho Chang
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Su Wei Lee
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Yun-Wei Chiang
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan.
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22
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Dissecting the Conformational Dynamics of the Bile Acid Transporter Homologue ASBT NM. J Mol Biol 2021; 433:166764. [PMID: 33359100 DOI: 10.1016/j.jmb.2020.166764] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 11/21/2022]
Abstract
Apical sodium-dependent bile acid transporter (ASBT) catalyses uphill transport of bile acids using the electrochemical gradient of Na+ as the driving force. The crystal structures of two bacterial homologues ASBTNM and ASBTYf have previously been determined, with the former showing an inward-facing conformation, and the latter adopting an outward-facing conformation accomplished by the substitution of the critical Na+-binding residue glutamate-254 with an alanine residue. While the two crystal structures suggested an elevator-like movement to afford alternating access to the substrate binding site, the mechanistic role of Na+ and substrate in the conformational isomerization remains unclear. In this study, we utilized site-directed alkylation monitored by in-gel fluorescence (SDAF) to probe the solvent accessibility of the residues lining the substrate permeation pathway of ASBTNM under different Na+ and substrate conditions, and interpreted the conformational states inferred from the crystal structures. Unexpectedly, the crosslinking experiments demonstrated that ASBTNM is a monomer protein, unlike the other elevator-type transporters, usually forming a homodimer or a homotrimer. The conformational dynamics observed by the biochemical experiments were further validated using DEER measuring the distance between the spin-labelled pairs. Our results revealed that Na+ ions shift the conformational equilibrium of ASBTNM toward the inward-facing state thereby facilitating cytoplasmic uptake of substrate. The current findings provide a novel perspective on the conformational equilibrium of secondary active transporters.
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23
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Pays E. The function of apolipoproteins L (APOLs): relevance for kidney disease, neurotransmission disorders, cancer and viral infection. FEBS J 2021; 288:360-381. [PMID: 32530132 PMCID: PMC7891394 DOI: 10.1111/febs.15444] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/24/2020] [Accepted: 06/03/2020] [Indexed: 12/17/2022]
Abstract
The discovery that apolipoprotein L1 (APOL1) is the trypanolytic factor of human serum raised interest about the function of APOLs, especially following the unexpected finding that in addition to their protective action against sleeping sickness, APOL1 C-terminal variants also cause kidney disease. Based on the analysis of the structure and trypanolytic activity of APOL1, it was proposed that APOLs could function as ion channels of intracellular membranes and be involved in mechanisms triggering programmed cell death. In this review, the recent finding that APOL1 and APOL3 inversely control the synthesis of phosphatidylinositol-4-phosphate (PI(4)P) by the Golgi PI(4)-kinase IIIB (PI4KB) is commented. APOL3 promotes Ca2+ -dependent activation of PI4KB, but due to their increased interaction with APOL3, APOL1 C-terminal variants can inactivate APOL3, leading to reduction of Golgi PI(4)P synthesis. The impact of APOLs on several pathological processes that depend on Golgi PI(4)P levels is discussed. I propose that through their effect on PI4KB activity, APOLs control not only actomyosin activities related to vesicular trafficking, but also the generation and elongation of autophagosomes induced by inflammation.
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Affiliation(s)
- Etienne Pays
- Laboratory of Molecular ParasitologyIBMMUniversité Libre de BruxellesGosseliesBelgium
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24
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Lan YJ, Yeh PS, Kao TY, Lo YC, Sue SC, Chen YW, Hwang DW, Chiang YW. Anti-apoptotic BCL-2 regulation by changes in dynamics of its long unstructured loop. Commun Biol 2020; 3:668. [PMID: 33184407 PMCID: PMC7665024 DOI: 10.1038/s42003-020-01390-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 10/19/2020] [Indexed: 12/13/2022] Open
Abstract
BCL-2, a key protein in inhibiting apoptosis, has a 65-residue-long highly flexible loop domain (FLD) located on the opposite side of its ligand-binding groove. In vivo phosphorylation of the FLD enhances the affinity of BCL-2 for pro-apoptotic ligands, and consequently anti-apoptotic activity. However, it remains unknown as to how the faraway, unstructured FLD modulates the affinity. Here we investigate the protein-ligand interactions by fluorescence techniques and monitor protein dynamics by DEER and NMR spectroscopy tools. We show that phosphomimetic mutations on the FLD lead to a reduction in structural flexibility, hence promoting ligand access to the groove. The bound pro-apoptotic ligands can be displaced by the BCL-2-selective inhibitor ABT-199 efficiently, and thus released to trigger apoptosis. We show that changes in structural flexibility on an unstructured loop can activate an allosteric protein that is otherwise structurally inactive.
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Affiliation(s)
- Yu-Jing Lan
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Pei-Shan Yeh
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Te-Yu Kao
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan
| | - Yuan-Chao Lo
- Biomedical Translation Research Center, Academia Sinica, Taipei, Taiwan
| | - Shih-Che Sue
- Institute of Bioinformatics and Structural Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Yu-Wen Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Dennis W Hwang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
| | - Yun-Wei Chiang
- Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan.
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25
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Cardiolipin in Immune Signaling and Cell Death. Trends Cell Biol 2020; 30:892-903. [DOI: 10.1016/j.tcb.2020.09.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 08/30/2020] [Accepted: 09/07/2020] [Indexed: 12/25/2022]
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26
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Pera M, Montesinos J, Larrea D, Agrawal RR, Velasco KR, Stavrovskaya IG, Yun TD, Area-Gomez E. MAM and C99, key players in the pathogenesis of Alzheimer's disease. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2020; 154:235-278. [PMID: 32739006 DOI: 10.1016/bs.irn.2020.03.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inter-organelle communication is a rapidly-expanding field that has transformed our understanding of cell biology and pathology. Organelle-organelle contact sites can generate transient functional domains that act as enzymatic hubs involved in the regulation of cellular metabolism and intracellular signaling. One of these hubs is located in areas of the endoplasmic reticulum (ER) connected to mitochondria, called mitochondria-associated ER membranes (MAM). These MAM are transient lipid rafts intimately involved in cholesterol and phospholipid metabolism, calcium homeostasis, and mitochondrial function and dynamics. In addition, γ-secretase-mediated proteolysis of the amyloid precursor protein 99-aa C-terminal fragment (C99) to form amyloid β also occurs at the MAM. Our most recent data indicates that in Alzheimer's disease, increases in uncleaved C99 levels at the MAM provoke the upregulation of MAM-resident functions, resulting in the loss of lipid homeostasis, and mitochondrial dysfunction. Here, we discuss the relevance of these findings in the field, and the contribution of C99 and MAM dysfunction to Alzheimer's disease neuropathology.
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Affiliation(s)
- Marta Pera
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States; Basic Sciences Department, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Sant Cugat del Vallés, Barcelona, Spain.
| | - Jorge Montesinos
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY, United States
| | - Delfina Larrea
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - Rishi R Agrawal
- Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States
| | - Kevin R Velasco
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - Irina G Stavrovskaya
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - Taekyung D Yun
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - Estela Area-Gomez
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY, United States; Institute of Human Nutrition, Columbia University Irving Medical Center, New York, NY, United States.
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27
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Song L, Huang Y, Zhang X, Han S, Hou M, Li H. Downregulation of microRNA-224-3p Hampers Retinoblastoma Progression via Activation of the Hippo-YAP Signaling Pathway by Increasing LATS2. Invest Ophthalmol Vis Sci 2020; 61:32. [PMID: 32186675 PMCID: PMC7401717 DOI: 10.1167/iovs.61.3.32] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Purpose The pivotal role of microRNAs (miRNAs or miRs) has been proved in the pathogenesis of retinoblastoma. miR-224-3p is demonstrated to be involved in several tumors. However, the underlying mechanism of miR-224-3p in retinoblastoma is yet to be investigated. Therefore, this study was designed to identify the regulation of miR-224-3p in human retinoblastoma. Methods The expression pattern of miR-224-3p and large tumor suppressor 2 (LATS2) in retinoblastoma was measured by reverse transcription quantitative polymerase chain reaction. Afterward, the interaction between miR-224-3p and LATS2 was identified using a dual luciferase reporter gene assay. Next, gain-of-function and loss-of-function approaches were employed to examine the effects of miR-224-3p and LATS2 as well as their interaction on cell apoptosis, proliferation and angiogenesis abilities, and tumorigenesis. Whether the Hippo-YAP signaling pathway was involved in tumorigenesis was analyzed by determining downstream genes. Results LATS2 was downregulated in retinoblastoma, and its overexpression promoted apoptosis and suppressed proliferation of retinoblastoma cells. miR-224-3p, highly expressed in retinoblastoma, inhibited the expression of its target gene LATS2, which inhibited activation of the Hippo-YAP signaling pathway. Suppression of miR-224-3p promoted apoptosis while suppressing the proliferation of retinoblastoma cells and angiogenesis. Tumor progression induced by upregulation of miR-224-3p was diminished by restoration of LATS2. It was observed that tumor growth and angiogenesis were reduced by depleted miR-224-3p in the animal experiments. Conclusions The present study suggests that miR-224-3p targets LATS2 and blocks the Hippo-YAP signaling pathway activation, thus preventing the progression of retinoblastoma, which could be a new therapeutic target for retinoblastoma.
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Hauseman ZJ, Harvey EP, Newman CE, Wales TE, Bucci JC, Mintseris J, Schweppe DK, David L, Fan L, Cohen DT, Herce HD, Mourtada R, Ben-Nun Y, Bloch NB, Hansen SB, Wu H, Gygi SP, Engen JR, Walensky LD. Homogeneous Oligomers of Pro-apoptotic BAX Reveal Structural Determinants of Mitochondrial Membrane Permeabilization. Mol Cell 2020; 79:68-83.e7. [PMID: 32533918 PMCID: PMC7472837 DOI: 10.1016/j.molcel.2020.05.029] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/13/2020] [Accepted: 05/20/2020] [Indexed: 10/24/2022]
Abstract
BAX is a pro-apoptotic protein that transforms from a cytosolic monomer into a toxic oligomer that permeabilizes the mitochondrial outer membrane. How BAX monomers assemble into a higher-order conformation, and the structural determinants essential to membrane permeabilization, remain a mechanistic mystery. A key hurdle has been the inability to generate a homogeneous BAX oligomer (BAXO) for analysis. Here, we report the production and characterization of a full-length BAXO that recapitulates physiologic BAX activation. Multidisciplinary studies revealed striking conformational consequences of oligomerization and insight into the macromolecular structure of oligomeric BAX. Importantly, BAXO enabled the assignment of specific roles to particular residues and α helices that mediate individual steps of the BAX activation pathway, including unexpected functionalities of BAX α6 and α9 in driving membrane disruption. Our results provide the first glimpse of a full-length and functional BAXO, revealing structural requirements for the elusive execution phase of mitochondrial apoptosis.
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Affiliation(s)
- Zachary J Hauseman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Edward P Harvey
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Catherine E Newman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Thomas E Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Joel C Bucci
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Julian Mintseris
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Devin K Schweppe
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Liron David
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Lixin Fan
- Small Angle X-ray Scattering Core, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Daniel T Cohen
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Henry D Herce
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Rida Mourtada
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Yael Ben-Nun
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Noah B Bloch
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA
| | - Scott B Hansen
- The Scripps Research Institute-Florida, Jupiter, FL 33458, USA
| | - Hao Wu
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - John R Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Loren D Walensky
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA; Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, MA 02215, USA.
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Tan JX, Finkel T. Mitochondria as intracellular signaling platforms in health and disease. J Cell Biol 2020; 219:e202002179. [PMID: 32320464 PMCID: PMC7199861 DOI: 10.1083/jcb.202002179] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/15/2022] Open
Abstract
Mitochondria, long viewed solely in the context of bioenergetics, are increasingly emerging as critical hubs for intracellular signaling. Due to their bacterial origin, mitochondria possess their own genome and carry unique lipid components that endow these organelles with specialized properties to help orchestrate multiple signaling cascades. Mitochondrial signaling modulates diverse pathways ranging from metabolism to redox homeostasis to cell fate determination. Here, we review recent progress in our understanding of how mitochondria serve as intracellular signaling platforms with a particular emphasis on lipid-mediated signaling, innate immune activation, and retrograde signaling. We further discuss how these signaling properties might potentially be exploited to develop new therapeutic strategies for a range of age-related conditions.
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Affiliation(s)
- Jay X. Tan
- Aging Institute, University of Pittsburgh School of Medicine/University of Pittsburgh Medical Center, Pittsburgh, PA
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Toren Finkel
- Aging Institute, University of Pittsburgh School of Medicine/University of Pittsburgh Medical Center, Pittsburgh, PA
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA
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30
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HE S, MA X, MENG Q, LU J, QIN X, FANG S, MA C. Effects and mechanisms of water-soluble Semen cassiae polysaccharide on retinitis pigmentosa in rats. FOOD SCIENCE AND TECHNOLOGY 2020. [DOI: 10.1590/fst.32718] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
| | - Xiang MA
- Dalian Medical University, China
| | | | | | | | | | - Cong MA
- Dalian Medical University, China
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31
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PEGylation-based strategy to identify pathways involved in the activation of apoptotic BAX protein. Biochim Biophys Acta Gen Subj 2020; 1864:129541. [PMID: 31987956 DOI: 10.1016/j.bbagen.2020.129541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 01/21/2020] [Accepted: 01/23/2020] [Indexed: 10/25/2022]
Abstract
BACKGROUND BAX activation is a crucial step for commitment to apoptosis. Several activators, such as BimBH3-based therapeutic peptides and cleaved Bid (cBid) protein, can trigger BAX-mediated apoptosis, but it is unclear whether they proceed through the same pathway. METHODS Here we utilize PEGylation-based approach, which is shown to efficiently shield individual binding grooves in BAX from activators, to investigate and reveal that the activators take different routes to induce BAX-mediated apoptosis. Various spectroscopic/biochemical tools, including electron spin resonance, circular dichroism, fluorescence recovery after photobleaching, and label-transfer assay, were employed to reveal details in the processes. RESULTS We observe a key mutant BAX 164-PEG that acts differently in response to cBid and BimBH3 stimuli. While BimBH3 directly interacts with the trigger groove (TG) to induce the conformational changes in BAX that includes the release of α9 from the canonical groove (CG) and oligomerization, cBid engages with CG and works with mitochondrial lipids to fully activate BAX. CONCLUSION PEGylation-based approach is proven useful to shield individual binding grooves of BAX from apoptotic stimuli. Groove engagement in CG of BAX is required for a full cBid-induced BAX activation. This study has identified differences in the pathways involved during the initiation of BAX activation by full-length cBid protein versus synthetic BimBH3-based peptides. GENERAL SIGNIFICANCE Our finding is potentially valuable for therapeutic application as the pore-forming activity of 164-PEG is independent from the cBid-mediated apoptotic pathways, but can be administrated by the synthetic short peptides.
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32
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Yu R, Lendahl U, Nistér M, Zhao J. Regulation of Mammalian Mitochondrial Dynamics: Opportunities and Challenges. Front Endocrinol (Lausanne) 2020; 11:374. [PMID: 32595603 PMCID: PMC7300174 DOI: 10.3389/fendo.2020.00374] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/12/2020] [Indexed: 01/01/2023] Open
Abstract
Mitochondria are highly dynamic organelles and important for a variety of cellular functions. They constantly undergo fission and fusion events, referred to as mitochondrial dynamics, which affects the shape, size, and number of mitochondria in the cell, as well as mitochondrial subcellular transport, mitochondrial quality control (mitophagy), and programmed cell death (apoptosis). Dysfunctional mitochondrial dynamics is associated with various human diseases. Mitochondrial dynamics is mediated by a set of mitochondria-shaping proteins in both yeast and mammals. In this review, we describe recent insights into the potential molecular mechanisms underlying mitochondrial fusion and fission, particularly highlighting the coordinating roles of different mitochondria-shaping proteins in the processes, as well as the roles of the endoplasmic reticulum (ER), the actin cytoskeleton and membrane phospholipids in the regulation of mitochondrial dynamics. We particularly focus on emerging roles for the mammalian mitochondrial proteins Fis1, Mff, and MIEFs (MIEF1 and MIEF2) in regulating the recruitment of the cytosolic Drp1 to the surface of mitochondria and how these proteins, especially Fis1, mediate crosstalk between the mitochondrial fission and fusion machineries. In summary, this review provides novel insights into the molecular mechanisms of mammalian mitochondrial dynamics and the involvement of these mechanisms in apoptosis and autophagy.
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Affiliation(s)
- Rong Yu
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
| | - Urban Lendahl
- Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden
| | - Monica Nistér
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
- *Correspondence: Monica Nistér
| | - Jian Zhao
- Department of Oncology-Pathology, Karolinska Institutet, Karolinska University Hospital Solna, Stockholm, Sweden
- Jian Zhao
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Flores-Romero H, Ros U, García-Sáez AJ. A lipid perspective on regulated cell death. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2019; 351:197-236. [PMID: 32247580 DOI: 10.1016/bs.ircmb.2019.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Lipids are fundamental to life as structural components of cellular membranes and for signaling. They are also key regulators of different cellular processes such as cell division, proliferation, and death. Regulated cell death (RCD) requires the engagement of lipids and lipid metabolism for the initiation and execution of its killing machinery. The permeabilization of lipid membranes is a hallmark of RCD that involves, for each kind of cell death, a unique lipid profile. While the permeabilization of the mitochondrial outer membrane allows the release of apoptotic factors to the cytosol during apoptosis, permeabilization of the plasma membrane facilitates the release of intracellular content in other nonapoptotic types of RCD like necroptosis and ferroptosis. Lipids and lipid membranes are important accessory molecules required for the activation of protein executors of cell death such as BAX in apoptosis and MLKL in necroptosis. Peroxidation of membrane phospholipids and the subsequent membrane destabilization is a prerequisite to ferroptosis. Here, we discuss how lipids are essential players in apoptosis, the most common form of RCD, and also their role in necroptosis and ferroptosis. Altogether, we aim to highlight the contribution of lipids and membrane dynamics in cell death regulation.
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Affiliation(s)
- Hector Flores-Romero
- Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Uris Ros
- Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany
| | - Ana J García-Sáez
- Interfaculty Institute of Biochemistry, Eberhard-Karls-Universität Tübingen, Tübingen, Germany.
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Lai Y, Kuo Y, Chiang Y. Identifying Protein Conformational Dynamics Using Spin‐label ESR. Chem Asian J 2019; 14:3981-3991. [DOI: 10.1002/asia.201900855] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 08/02/2019] [Indexed: 12/24/2022]
Affiliation(s)
- Yei‐Chen Lai
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
- Department of Chemistry&Biochemistry University of California Santa Barbara CA 93106-9510 USA
| | - Yun‐Hsuan Kuo
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
| | - Yun‐Wei Chiang
- Department of Chemistry National Tsing Hua University Hsinchu 30013 Taiwan
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Ghio S, Camilleri A, Caruana M, Ruf VC, Schmidt F, Leonov A, Ryazanov S, Griesinger C, Cauchi RJ, Kamp F, Giese A, Vassallo N. Cardiolipin Promotes Pore-Forming Activity of Alpha-Synuclein Oligomers in Mitochondrial Membranes. ACS Chem Neurosci 2019; 10:3815-3829. [PMID: 31356747 DOI: 10.1021/acschemneuro.9b00320] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aggregation of the amyloid-forming α-synuclein (αS) protein is closely associated with the etiology of Parkinson's disease (PD), the most common motor neurodegenerative disorder. Many studies have shown that soluble aggregation intermediates of αS, termed oligomers, permeabilize a variety of phospholipid membranes; thus, membrane disruption may represent a key pathogenic mechanism of αS toxicity. Given the centrality of mitochondrial dysfunction in PD, we therefore probed the formation of ion-permeable pores by αS oligomers in planar lipid bilayers reflecting the complex phospholipid composition of mitochondrial membranes. Using single-channel electrophysiology, we recorded distinct multilevel conductances (100-400 pS) with stepwise current transitions, typical of protein-bound nanopores, in mitochondrial-like membranes. Crucially, we observed that the presence of cardiolipin (CL), the signature phospholipid of mitochondrial membranes, enhanced αS-lipid interaction and the membrane pore-forming activity of αS oligomers. Further, preincubation of isolated mitochondria with a CL-specific dye protected against αS oligomer-induced mitochondrial swelling and release of cytochrome c. Hence, we favor a scenario in which αS oligomers directly porate a local lipid environment rich in CL, for instance outer mitochondrial contact sites or the inner mitochondrial membrane, to induce mitochondrial dysfunction. Pharmacological modulation of αS pore complex formation might thus preserve mitochondrial membrane integrity and alleviate mitochondrial dysfunction in PD.
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Affiliation(s)
- Stephanie Ghio
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Angelique Camilleri
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Mario Caruana
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Viktoria C. Ruf
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Felix Schmidt
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Andrei Leonov
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Sergey Ryazanov
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
- MODAG GmbH, Wendelsheim, Germany
| | - Christian Griesinger
- Department of NMR-based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Ruben J. Cauchi
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
| | - Frits Kamp
- Biomedical Center, Metabolic Biochemistry, Ludwig-Maximilians-University, Munich, Germany
| | - Armin Giese
- Center for Neuropathology and Prion Research, Ludwig-Maximilians-University, Munich, Germany
| | - Neville Vassallo
- Department of Physiology and Biochemistry and Centre for Molecular Medicine and Biobanking, University of Malta, Msida, Malta
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Praharaj PP, Naik PP, Panigrahi DP, Bhol CS, Mahapatra KK, Patra S, Sethi G, Bhutia SK. Intricate role of mitochondrial lipid in mitophagy and mitochondrial apoptosis: its implication in cancer therapeutics. Cell Mol Life Sci 2019; 76:1641-1652. [PMID: 30539200 PMCID: PMC11105358 DOI: 10.1007/s00018-018-2990-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 12/05/2018] [Accepted: 12/06/2018] [Indexed: 02/06/2023]
Abstract
The efficacy of chemotherapy is mostly restricted by the drug resistance developed during the course of cancer treatment. Mitophagy, as a pro-survival mechanism, crucially maintains mitochondrial homeostasis and it is one of the mechanisms that cancer cells adopt for their progression. On the other hand, mitochondrial apoptosis, a precisely regulated form of cell death, acts as a tumor-suppressive mechanism by targeting cancer cells. Mitochondrial lipids, such as cardiolipin, ceramide, and sphingosine-1-phosphate, act as a mitophageal signal for the clearance of damaged mitochondria by interacting with mitophagic machinery as well as activate mitochondrial apoptosis via the release of cytochrome c into the cytoplasm. In the recent time, the lipid-mediated lethal mitophagy has also been used as an alternative approach to abolish the survival role of lipid in cancer. Therefore, by targeting mitochondrial lipids in cancer cells, the detailed mechanism linked to drug resistance can be unraveled. In this review, we precisely discuss the current knowledge about the multifaceted role of mitochondrial lipid in regulating mitophagy and mitochondrial apoptosis and its application in effective cancer therapy.
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Affiliation(s)
- Prakash P Praharaj
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Odisha, 769008, India
| | - Prajna P Naik
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Odisha, 769008, India
- PG Department of Zoology, Vikram Deb (Auto) College, Jeypore, Odisha, 764001, India
| | - Debasna P Panigrahi
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Odisha, 769008, India
| | - Chandra S Bhol
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Odisha, 769008, India
| | - Kewal K Mahapatra
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Odisha, 769008, India
| | - Srimanta Patra
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Odisha, 769008, India
| | - Gautam Sethi
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117600, Singapore
| | - Sujit Kumar Bhutia
- Department of Life Science, National Institute of Technology Rourkela, Rourkela, Odisha, 769008, India.
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Yu H, Yuan B, Chu Q, Wang C, Bi H. Protective roles of isoastilbin against Alzheimer's disease via Nrf2‑mediated antioxidation and anti‑apoptosis. Int J Mol Med 2019; 43:1406-1416. [PMID: 30664148 PMCID: PMC6365075 DOI: 10.3892/ijmm.2019.4058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/07/2019] [Indexed: 12/18/2022] Open
Abstract
By analyzing the L‑glutamic acid (L‑Glu)‑induced apoptosis of PC12 cells and an AlCl3 combined with D‑galactose (D‑gal)‑developed Alzheimer's disease (AD) mouse model, the protective effects of isoastilbin (IAB) against AD were systematically investigated in the present study. Pre‑incubation with IAB for 3 h prior to treatment with 25 mM L‑Glu decreased cell viability and inhibited apoptosis, suppressed the accumulation of intracellular reactive oxygen species, and restored mitochondrial membrane potential in PC12 cells induced by L‑Glu. In mice with AD, the reduced escape latency time in the water maze test, suppressed chronic movement in the center area of an open field test and enhanced ability to seek hidden food in a Y maze test indicated that abnormal behaviors had improved after 28 days of treatment with IAB. Furthermore, IAB reduced the deposition of amyloid β (Aβ) and the expression of phosphorylated‑Tau in the mouse brain and enhanced the serum levels of Aβ. IAB ameliorated the oxidative stress via modulating the levels of associated enzymes and improved the functioning of the central cholinergic system, as indicated by an increase in acetylcholine and choline acetyltransferase concentrations. The expression levels of acetylcholine esterase were reduced in the mouse brain in response to IAB pre‑treatment. In cells and brain tissue, IAB regulated the expression levels of pro‑ and anti‑apoptotic proteins and enhanced the nuclear levels of NF‑E2p45‑related factor 2 (Nrf2); subsequently, IAB further enhanced the expression of superoxide dismutase 1, catalase, and heme oxygenase‑1 and ‑2. The findings of the present study indicated that the protection of IAB against AD is at least partially associated with its antioxidation and anti‑apoptotic properties.
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Affiliation(s)
- Hong Yu
- Departments of Otolaryngology Head and Neck Surgery, Jilin 130021, P.R. China
| | - Bo Yuan
- Urology, The First Hospital of Jilin University, Jilin University, Changchun, Jilin 130021, P.R. China
| | - Qiubo Chu
- School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Chunyue Wang
- School of Life Sciences, Jilin University, Changchun, Jilin 130012, P.R. China
| | - Hui Bi
- Department of Anesthesiology, Hospital of Stomatology, Jilin University, Changchun, Jilin 130021, P.R. China
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Area-Gomez E, Guardia-Laguarta C, Schon EA, Przedborski S. Mitochondria, OxPhos, and neurodegeneration: cells are not just running out of gas. J Clin Invest 2019; 129:34-45. [PMID: 30601141 DOI: 10.1172/jci120848] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mitochondrial respiratory deficiencies have been observed in numerous neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. For decades, these reductions in oxidative phosphorylation (OxPhos) have been presumed to trigger an overall bioenergetic crisis in the neuron, resulting in cell death. While the connection between respiratory defects and neuronal death has never been proven, this hypothesis has been supported by the detection of nonspecific mitochondrial DNA mutations in these disorders. These findings led to the notion that mitochondrial respiratory defects could be initiators of these common neurodegenerative disorders, instead of being consequences of a prior insult, a theory we believe to be misconstrued. Herein, we review the roots of this mitochondrial hypothesis and offer a new perspective wherein mitochondria are analyzed not only from the OxPhos point of view, but also as a complex organelle residing at the epicenter of many metabolic pathways.
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Affiliation(s)
| | | | - Eric A Schon
- Department of Neurology.,Department of Genetics and Development, Columbia University Medical Center, New York, New York, USA
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