651
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Awan FM, Obaid A, Ikram A, Janjua HA. Mutation-Structure-Function Relationship Based Integrated Strategy Reveals the Potential Impact of Deleterious Missense Mutations in Autophagy Related Proteins on Hepatocellular Carcinoma (HCC): A Comprehensive Informatics Approach. Int J Mol Sci 2017; 18:ijms18010139. [PMID: 28085066 PMCID: PMC5297772 DOI: 10.3390/ijms18010139] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 11/14/2016] [Accepted: 11/16/2016] [Indexed: 12/13/2022] Open
Abstract
Autophagy, an evolutionary conserved multifaceted lysosome-mediated bulk degradation system, plays a vital role in liver pathologies including hepatocellular carcinoma (HCC). Post-translational modifications (PTMs) and genetic variations in autophagy components have emerged as significant determinants of autophagy related proteins. Identification of a comprehensive spectrum of genetic variations and PTMs of autophagy related proteins and their impact at molecular level will greatly expand our understanding of autophagy based regulation. In this study, we attempted to identify high risk missense mutations that are highly damaging to the structure as well as function of autophagy related proteins including LC3A, LC3B, BECN1 and SCD1. Number of putative structural and functional residues, including several sites that undergo PTMs were also identified. In total, 16 high-risk SNPs in LC3A, 18 in LC3B, 40 in BECN1 and 43 in SCD1 were prioritized. Out of these, 2 in LC3A (K49A, K51A), 1 in LC3B (S92C), 6 in BECN1 (S113R, R292C, R292H, Y338C, S346Y, Y352H) and 6 in SCD1 (Y41C, Y55D, R131W, R135Q, R135W, Y151C) coincide with potential PTM sites. Our integrated analysis found LC3B Y113C, BECN1 I403T, SCD1 R126S and SCD1 Y218C as highly deleterious HCC-associated mutations. This study is the first extensive in silico mutational analysis of the LC3A, LC3B, BECN1 and SCD1 proteins. We hope that the observed results will be a valuable resource for in-depth mechanistic insight into future investigations of pathological missense SNPs using an integrated computational platform.
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Affiliation(s)
- Faryal Mehwish Awan
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
| | - Ayesha Obaid
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
| | - Aqsa Ikram
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
| | - Hussnain Ahmed Janjua
- Department of Industrial Biotechnology, Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), H-12 Islamabad 44000, Pakistan.
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652
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Nguyen HM, El Hajj H, El Hajj R, Tawil N, Berry L, Lebrun M, Bordat Y, Besteiro S. Toxoplasma gondii
autophagy-related protein ATG9 is crucial for the survival of parasites in their host. Cell Microbiol 2017; 19. [DOI: 10.1111/cmi.12712] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 12/12/2016] [Accepted: 12/15/2016] [Indexed: 12/26/2022]
Affiliation(s)
- Hoa Mai Nguyen
- DIMNP-UMR 5235 CNRS; Université de Montpellier; Montpellier France
| | - Hiba El Hajj
- Faculty of Medicine; American University of Beirut; Beirut Lebanon
| | - Rana El Hajj
- Faculty of Medicine; American University of Beirut; Beirut Lebanon
| | - Nadim Tawil
- Faculty of Medicine; American University of Beirut; Beirut Lebanon
| | - Laurence Berry
- DIMNP-UMR 5235 CNRS; Université de Montpellier; Montpellier France
| | - Maryse Lebrun
- DIMNP-UMR 5235 CNRS; Université de Montpellier; Montpellier France
| | - Yann Bordat
- DIMNP-UMR 5235 CNRS; Université de Montpellier; Montpellier France
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653
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Li R, Yuan F, Fu W, Zhang L, Zhang N, Wang Y, Ma K, Li X, Wang L, Zhu WG, Zhao Y. Serine/Threonine Kinase Unc-51-like Kinase-1 (Ulk1) Phosphorylates the Co-chaperone Cell Division Cycle Protein 37 (Cdc37) and Thereby Disrupts the Stability of Cdc37 Client Proteins. J Biol Chem 2017; 292:2830-2841. [PMID: 28073914 DOI: 10.1074/jbc.m116.762443] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/04/2017] [Indexed: 12/17/2022] Open
Abstract
The serine/threonine kinase Unc-51-like kinase-1 (Ulk1) is thought to be essential for induction of autophagy, an intracellular bulk degradation process that is activated by various stresses. Although several proteins have been suggested as Ulk1 substrates during autophagic process, it still remains largely unknown about Ulk1's physiological substrates. Here, by performing in vitro and in vivo phosphorylation assay, we report that the co-chaperone cell division cycle protein 37 (Cdc37) is a Ulk1 substrate. Ulk1-mediated phosphorylation of Ser-339 in Cdc37 compromised the recruitment of client kinases to a complex comprising Cdc37 and heat shock protein 90 (Hsp90) but only modestly affected Cdc37 binding to Hsp90. Because the recruitment of protein kinase clients to the Hsp90 complex is essential for their stability and functions, Ser-339 phosphorylation of Cdc37 disrupts its ability as a co-chaperone to coordinate Hsp90. Hsp90 inhibitors are cancer chemotherapeutic agents by inducing depletion of clients, many of which are oncogenes. Upon treatment with an Hsp90 inhibitor in cancer cells, Ulk1 promoted the degradation of Hsp90-Cdc37 client kinases, resulting in increased cellular sensitivity to Hsp90 inhibitors. Thus, our study provides evidence for an anti-proliferative role of Ulk1 in response to Hsp90 inhibition in cancer cells.
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Affiliation(s)
- Ran Li
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Fengjie Yuan
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Wan Fu
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Luyao Zhang
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Nan Zhang
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yanan Wang
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Ke Ma
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Xue Li
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Lina Wang
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Wei-Guo Zhu
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.,the Center for Life Sciences, Peking-Tsinghua University, Beijing 100871, China, and.,the Department of Biochemistry and Molecular Biology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Ying Zhao
- From the Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China,
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654
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The Endoplasmic Reticulum and the Cellular Reticular Network. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:61-76. [DOI: 10.1007/978-3-319-55858-5_4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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655
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Lührmann A, Newton HJ, Bonazzi M. Beginning to Understand the Role of the Type IV Secretion System Effector Proteins in Coxiella burnetii Pathogenesis. Curr Top Microbiol Immunol 2017. [PMID: 29536362 DOI: 10.1007/978-3-319-75241-9_10] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Coxiella burnetii is the etiological agent of the zoonotic disease Q fever, which manifests in severe outbreaks and is associated with important health and economic burden. Moreover, C. burnetii belongs to the list of class B bioterrorism organisms, as it is an airborne and highly infective pathogen with remarkable resistance to environmental stresses. Detailed study of the host-pathogen interaction during C. burnetii infection has been hampered due to the obligate intracellular nature of this pathogen. However, the development of an axenic culture medium, together with the implementation of bioinformatics tools and high-content screening approaches, have significantly progressed C. burnetii research in the last decade. This has facilitated identification of the Dot/Icm type IV secretion system (T4SS) as an essential virulence factor. T4SS is used to deliver an arsenal of effector proteins into the cytoplasm of the host cell. These effectors mediate the survival of the host cell and the development of very large replicative compartments called Coxiella-containing vacuoles (CCVs). Biogenesis of the CCV relies on T4SS-dependent re-routing of numerous intracellular trafficking pathways to deliver membranes and nutrients that are essential for bacterial replication. This review aims to illustrate the key milestones that have contributed to ascribe C. burnetii as a model organism for the study of host/pathogen interactions as well as presenting an up-to-date description of our knowledge of the cell biology of C. burnetii infections.
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Affiliation(s)
- Anja Lührmann
- Mikrobiologisches Institut-Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Wasserturmstraße 3/5, 91054, Erlangen, Germany.
| | - Hayley J Newton
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.
| | - Matteo Bonazzi
- Institut de Recherche En Infectiologie de Montpellier (IRIM), CNRS, UMR9004, Université de Montpellier, Montpellier, France.
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656
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Abstract
Leucine-rich repeat kinase 2 (LRRK2) has been implicated in a wide range of cellular processes, including the catabolic pathways collectively described as autophagy. In this chapter, the evidence linking LRRK2 to autophagy will be examined, along with how regulation of autophagy and lysosomal pathways may provide a nexus between the physiological function of this protein and the different diseases with which it has been associated. Data from cellular and animal models for LRRK2 function and dysfunction support a role in the regulation and control of autophagic pathways in the cell, although the extant results do not provide a clear indication as to whether LRRK2 is a positive or negative regulator of these pathways, and there are conflicting data as to the impact of mutations in LRRK2 causative for Parkinson's disease. Given that LRRK2 is a priority drug target for Parkinson's, the evidence suggesting that knockout or inhibition of LRRK2 can result in deregulation of autophagy may have important implications and is discussed in the context of our wider understanding of LRRK2.
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Affiliation(s)
- Claudia Manzoni
- School of Pharmacy, University of Reading, Whiteknights, Reading, UK
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK
| | - Patrick A Lewis
- School of Pharmacy, University of Reading, Whiteknights, Reading, UK.
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, UK.
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657
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Fonseca BM, Teixeira NA, Correia-da-Silva G. Cannabinoids as Modulators of Cell Death: Clinical Applications and Future Directions. Rev Physiol Biochem Pharmacol 2017; 173:63-88. [PMID: 28425013 DOI: 10.1007/112_2017_3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Endocannabinoids are bioactive lipids that modulate various physiological processes through G-protein-coupled receptors (CB1 and CB2) and other putative targets. By sharing the activation of the same receptors, some phytocannabinoids and a multitude of synthetic cannabinoids mimic the effects of endocannabinoids. In recent years, a growing interest has been dedicated to the study of cannabinoids properties for their analgesic, antioxidant, anti-inflammatory and neuroprotective effects. In addition to these well-recognized effects, various studies suggest that cannabinoids may affect cell survival, cell proliferation or cell death. These observations indicate that cannabinoids may play an important role in the regulation of cellular homeostasis and, thus, may contribute to tissue remodelling and cancer treatment. For a long time, the study of cannabinoid receptor signalling has been focused on the classical adenylyl cyclase/cyclic AMP/protein kinase A (PKA) pathway. However, this pathway does not totally explain the wide array of biological responses to cannabinoids. In addition, the diversity of receptors and signalling pathways that endocannabinoids modulate offers an interesting opportunity for the development of specific molecules to disturb selectively the endogenous system. Moreover, emerging evidences suggest that cannabinoids ability to limit cell proliferation and to induce tumour-selective cell death may offer a novel strategy in cancer treatment. This review describes the main properties of cannabinoids in cell death and attempts to clarify the different pathways triggered by these compounds that may help to understand the complexity of respective molecular mechanisms and explore the potential clinical benefit of cannabinoids use in cancer therapies.
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Affiliation(s)
- B M Fonseca
- UCIBIO, REQUIMTE, Laboratório de Bioquímica, Departamento Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal.
| | - N A Teixeira
- UCIBIO, REQUIMTE, Laboratório de Bioquímica, Departamento Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
| | - G Correia-da-Silva
- UCIBIO, REQUIMTE, Laboratório de Bioquímica, Departamento Ciências Biológicas, Faculdade de Farmácia da Universidade do Porto, Porto, Portugal
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658
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Role of Endoplasmic Reticulum-Mitochondria Communication in Type 2 Diabetes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 997:171-186. [DOI: 10.1007/978-981-10-4567-7_13] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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659
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660
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Bravo-San Pedro JM, Pietrocola F, Sica V, Izzo V, Sauvat A, Kepp O, Maiuri MC, Kroemer G, Galluzzi L. High-Throughput Quantification of GFP-LC3 + Dots by Automated Fluorescence Microscopy. Methods Enzymol 2016; 587:71-86. [PMID: 28253977 DOI: 10.1016/bs.mie.2016.10.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Macroautophagy is a specific variant of autophagy that involves a dedicated double-membraned organelle commonly known as autophagosome. Various methods have been developed to quantify the size of the autophagosomal compartment, which is an indirect indicator of macroautophagic responses, based on the peculiar ability of microtubule-associated protein 1 light chain 3 beta (MAP1LC3B; best known as LC3) to accumulate in forming autophagosomes upon maturation. One particularly convenient method to monitor the accumulation of mature LC3 within autophagosomes relies on a green fluorescent protein (GFP)-tagged variant of this protein and fluorescence microscopy. In physiological conditions, cells transfected temporarily or stably with a GFP-LC3-encoding construct exhibit a diffuse green fluorescence over the cytoplasm and nucleus. Conversely, in response to macroautophagy-promoting stimuli, the GFP-LC3 signal becomes punctate and often (but not always) predominantly cytoplasmic. The accumulation of GFP-LC3 in cytoplasmic dots, however, also ensues the blockage of any of the steps that ensure the degradation of mature autophagosomes, calling for the implementation of strategies that accurately discriminate between an increase in autophagic flux and an arrest in autophagic degradation. Various cell lines have been engineered to stably express GFP-LC3, which-combined with the appropriate controls of flux, high-throughput imaging stations, and automated image analysis-offer a relatively straightforward tool to screen large chemical or biological libraries for inducers or inhibitors of autophagy. Here, we describe a simple and robust method for the high-throughput quantification of GFP-LC3+ dots by automated fluorescence microscopy.
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Affiliation(s)
- J M Bravo-San Pedro
- Gustave Roussy Cancer Campus, Villejuif, France; INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France.
| | - F Pietrocola
- Gustave Roussy Cancer Campus, Villejuif, France; INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France
| | - V Sica
- Gustave Roussy Cancer Campus, Villejuif, France; INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France; Faculté de Medicine, Université Paris Saclay/Paris XI, Le Kremlin-Bicêtre, France
| | - V Izzo
- Gustave Roussy Cancer Campus, Villejuif, France; INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France
| | - A Sauvat
- INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France
| | - O Kepp
- INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France
| | - M C Maiuri
- Gustave Roussy Cancer Campus, Villejuif, France; INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France
| | - G Kroemer
- INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France; Metabolomics and Cell Biology Platforms, Gustave Roussy Cancer Campus, Villejuif, France; Pôle de Biologie, Hôpital Européen Georges Pompidou, AP-HP, Paris, France; Karolinska University Hospital, Stockholm, Sweden
| | - L Galluzzi
- Gustave Roussy Cancer Campus, Villejuif, France; INSERM, U1138, Paris, France; Equipe 11 labellisée par la Ligue Nationale contre le Cancer, Centre de Recherche des Cordeliers, Paris, France; Université Paris Descartes/Paris V, Sorbonne Paris Cité, Paris, France; Université Pierre et Marie Curie/Paris VI, Paris, France; Weill Cornell Medical College, New York, NY, United States.
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661
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HS1BP3 negatively regulates autophagy by modulation of phosphatidic acid levels. Nat Commun 2016; 7:13889. [PMID: 28004827 PMCID: PMC5412012 DOI: 10.1038/ncomms13889] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 11/09/2016] [Indexed: 12/20/2022] Open
Abstract
A fundamental question is how autophagosome formation is regulated. Here we show that the PX domain protein HS1BP3 is a negative regulator of autophagosome formation. HS1BP3 depletion increased the formation of LC3-positive autophagosomes and degradation of cargo both in human cell culture and in zebrafish. HS1BP3 is localized to ATG16L1- and ATG9-positive autophagosome precursors and we show that HS1BP3 binds phosphatidic acid (PA) through its PX domain. Furthermore, we find the total PA content of cells to be significantly upregulated in the absence of HS1BP3, as a result of increased activity of the PA-producing enzyme phospholipase D (PLD) and increased localization of PLD1 to ATG16L1-positive membranes. We propose that HS1BP3 regulates autophagy by modulating the PA content of the ATG16L1-positive autophagosome precursor membranes through PLD1 activity and localization. Our findings provide key insights into how autophagosome formation is regulated by a novel negative-feedback mechanism on membrane lipids. Autophagy must be tightly controlled at each step of the process. Here the authors show that HS1BP3 binds phosphatidic acid (PA) at autophagosome precursors and negatively regulates autophagosome formation by modulating the activity and localization of the PA-producing enzyme phospholipase D1.
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662
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Rivera-Monroy J, Musiol L, Unthan-Fechner K, Farkas Á, Clancy A, Coy-Vergara J, Weill U, Gockel S, Lin SY, Corey DP, Kohl T, Ströbel P, Schuldiner M, Schwappach B, Vilardi F. Mice lacking WRB reveal differential biogenesis requirements of tail-anchored proteins in vivo. Sci Rep 2016; 6:39464. [PMID: 28000760 PMCID: PMC5175141 DOI: 10.1038/srep39464] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 11/22/2016] [Indexed: 02/06/2023] Open
Abstract
Tail-anchored (TA) proteins are post-translationally inserted into membranes. The TRC40 pathway targets TA proteins to the endoplasmic reticulum via a receptor comprised of WRB and CAML. TRC40 pathway clients have been identified using in vitro assays, however, the relevance of the TRC40 pathway in vivo remains unknown. We followed the fate of TA proteins in two tissue-specific WRB knockout mouse models and found that their dependence on the TRC40 pathway in vitro did not predict their reaction to receptor depletion in vivo. The SNARE syntaxin 5 (Stx5) was extremely sensitive to disruption of the TRC40 pathway. Screening yeast TA proteins with mammalian homologues, we show that the particular sensitivity of Stx5 is conserved, possibly due to aggregation propensity of its cytoplasmic domain. We establish that Stx5 is an autophagy target that is inefficiently membrane-targeted by alternative pathways. Our results highlight an intimate relationship between the TRC40 pathway and cellular proteostasis.
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Affiliation(s)
- Jhon Rivera-Monroy
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Lena Musiol
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Kirsten Unthan-Fechner
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Ákos Farkas
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Anne Clancy
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Javier Coy-Vergara
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Uri Weill
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Sarah Gockel
- Department of Cardiology &Pulmonology, Universitätsmedizin Göttingen, D-37075 Göttingen, Germany
| | - Shuh-Yow Lin
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - David P Corey
- Howard Hughes Medical Institute and Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Tobias Kohl
- Department of Cardiology &Pulmonology, Universitätsmedizin Göttingen, D-37075 Göttingen, Germany
| | - Philipp Ströbel
- Institute of Pathology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Blanche Schwappach
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany.,Max-Planck Institute for Biophysical Chemistry, D-37077, Göttingen, Germany
| | - Fabio Vilardi
- Department of Molecular Biology, Universitätsmedizin Göttingen, D-37073 Göttingen, Germany
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663
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Hewitt G, Korolchuk VI. Repair, Reuse, Recycle: The Expanding Role of Autophagy in Genome Maintenance. Trends Cell Biol 2016; 27:340-351. [PMID: 28011061 DOI: 10.1016/j.tcb.2016.11.011] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 11/25/2016] [Accepted: 11/28/2016] [Indexed: 01/01/2023]
Abstract
(Macro)Autophagy is a catabolic pathway that delivers excess, aggregated, or damaged proteins and organelles to lysosomes for degradation. Autophagy is activated in response to numerous cellular stressors such as increased levels of reactive oxygen species (ROS) and low levels of cellular nutrients as well as DNA damage. Although autophagy occurs in the cytoplasm, its inhibition leads to accumulation of DNA damage and genomic instability. In the past few years, our understanding of the interplay between autophagy and genomic stability has greatly increased. In this review we summarize these recent advances in understanding the molecular mechanisms linking autophagy to DNA repair.
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Affiliation(s)
- Graeme Hewitt
- DSB Repair Metabolism Laboratory, The Francis Crick Institute, London NW1 1AT, UK.
| | - Viktor I Korolchuk
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE4 5PL, UK.
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664
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Trexel J, Yoon GS, Keswani RK, McHugh C, Yeomans L, Vitvitsky V, Banerjee R, Sud S, Sun Y, Rosania GR, Stringer KA. Macrophage-Mediated Clofazimine Sequestration Is Accompanied by a Shift in Host Energy Metabolism. J Pharm Sci 2016; 106:1162-1174. [PMID: 28007559 DOI: 10.1016/j.xphs.2016.12.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 02/07/2023]
Abstract
Prolonged (8 weeks) oral administration of clofazimine results in a profound pharmacodynamic response-bioaccumulation in macrophages (including Kupffer cells) as intracellular crystal-like drug inclusions (CLDIs) with an associated increase in interleukin-1 receptor antagonist production. Notably, CLDI formation in Kupffer cells concomitantly occurs with the formation of macrophage-centric granulomas. Accordingly, we sought to understand the impact of these events on host metabolism using 1H-nuclear magnetic resonance metabolomics. Mice received a clofazimine or vehicle-enriched (sham) diet for at least 8 weeks. At 2 weeks, the antimicrobial activity of clofazimine was evident by changes in urine metabolites. From 2 to 8 weeks, there was a striking change in metabolite levels indicative of a reorientation of host energy metabolism paralleling the onset of CLDI and granuloma formation. This was evidenced by a progressive reduction in urine levels of metabolites involved in one-carbon metabolism with corresponding increases in whole blood, and changes in metabolites associated with lipid, nucleotide and amino acid metabolism, and glycolysis. Although clofazimine-fed mice ate more, they gained less weight than control mice. Together, these results indicate that macrophage sequestration of clofazimine as CLDIs and granuloma formation is accompanied by a profound metabolic disruption in energy homeostasis and one-carbon metabolism.
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Affiliation(s)
- Julie Trexel
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109; NMR Metabolomics Laboratory, University of Michigan, Ann Arbor, Michigan 48109
| | - Gi S Yoon
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109
| | - Rahul K Keswani
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109
| | - Cora McHugh
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109; NMR Metabolomics Laboratory, University of Michigan, Ann Arbor, Michigan 48109
| | - Larisa Yeomans
- NMR Metabolomics Laboratory, University of Michigan, Ann Arbor, Michigan 48109
| | - Victor Vitvitsky
- Department of Biological Chemistry, School of Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Ruma Banerjee
- Department of Biological Chemistry, School of Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Sudha Sud
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109
| | - Yihan Sun
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109; NMR Metabolomics Laboratory, University of Michigan, Ann Arbor, Michigan 48109
| | - Gus R Rosania
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109
| | - Kathleen A Stringer
- Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109; NMR Metabolomics Laboratory, University of Michigan, Ann Arbor, Michigan 48109; Center for Computational Medicine and Bioinformatics, School of Medicine, University of Michigan, Ann Arbor, Michigan 48109.
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665
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Insights on Molecular Mechanisms of Chondrocytes Death in Osteoarthritis. Int J Mol Sci 2016; 17:ijms17122146. [PMID: 27999417 PMCID: PMC5187946 DOI: 10.3390/ijms17122146] [Citation(s) in RCA: 228] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Revised: 12/05/2016] [Accepted: 12/12/2016] [Indexed: 12/21/2022] Open
Abstract
Osteoarthritis (OA) is a joint pathology characterized by progressive cartilage degradation. Medical care is mainly based on alleviating pain symptoms. Compelling studies report the presence of empty lacunae and hypocellularity in cartilage with aging and OA progression, suggesting that chondrocyte cell death occurs and participates to OA development. However, the relative contribution of apoptosis per se in OA pathogenesis appears complex to evaluate. Indeed, depending on technical approaches, OA stages, cartilage layers, animal models, as well as in vivo or in vitro experiments, the percentage of apoptosis and cell death types can vary. Apoptosis, chondroptosis, necrosis, and autophagic cell death are described in this review. The question of cell death causality in OA progression is also addressed, as well as the molecular pathways leading to cell death in response to the following inducers: Fas, Interleukin-1β (IL-1β), Tumor Necrosis factor-α (TNF-α), leptin, nitric oxide (NO) donors, and mechanical stresses. Furthermore, the protective role of autophagy in chondrocytes is highlighted, as well as its decline during OA progression, enhancing chondrocyte cell death; the transition being mainly controlled by HIF-1α/HIF-2α imbalance. Finally, we have considered whether interfering in chondrocyte apoptosis or promoting autophagy could constitute therapeutic strategies to impede OA progression.
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666
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Why autophagy is good for retinal ganglion cells? Eye (Lond) 2016; 31:185-190. [PMID: 27983732 DOI: 10.1038/eye.2016.278] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 11/04/2016] [Indexed: 01/20/2023] Open
Abstract
Autophagy is a catabolic pathway that promotes the degradation and recycling of cellular components. Proteins, lipids, and even whole organelles are engulfed in autophagosomes and delivered to the lysosome for elimination. In response to stress, autophagy mediates the degradation of cell components, which are recycled to generate the nutrients and building blocks required to sustain cellular homeostasis. Moreover, it has an important role in cellular quality control, particularly in neurons, in which the total burden of altered proteins and damaged organelles cannot be reduced by redistribution to daughter cells through cell division. Autophagy occurs in all cells and tissues, and it is regulated by the Atg genes. The importance of this pathway has been recently recognized by the Nobel Prize in Physiology and Medicine award to Professor Yoshinori Ohsumi who was the discoverer of the first Atg genes in yeast in the 1990s. Research has only begun to examine the role of autophagy in the visual system. Both the retina and the eye are exposed to a variety of environmental insults and stressors, including genetic mutations and age-associated alterations that impair their function. Here, we review studies that have sought to explain autophagy's importance for retinal ganglion cells, and their implications for diseases like glaucoma and optic neuropathies.
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667
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Moscat J, Karin M, Diaz-Meco MT. p62 in Cancer: Signaling Adaptor Beyond Autophagy. Cell 2016; 167:606-609. [PMID: 27768885 DOI: 10.1016/j.cell.2016.09.030] [Citation(s) in RCA: 296] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 06/17/2016] [Accepted: 09/16/2016] [Indexed: 12/15/2022]
Abstract
Adaptor proteins participate in selective autophagy, which is critical for cellular detoxification and stress relief. However, new evidence supports an autophagy-independent key role of the adaptor p62 (encoded by the gene Sqstm1) in signaling functions central to tumor initiation in the epithelium and suppression of tumor progression in the stroma.
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Affiliation(s)
- Jorge Moscat
- Cancer Metabolism and Signaling Networks Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA.
| | - Michael Karin
- Laboratory of Signal Transduction and Gene Regulation Departments of Pharmacology and Pathology, University of California San Diego, 9500 Gilman Drive, La Jolla Ca 92093, USA
| | - Maria T Diaz-Meco
- Cancer Metabolism and Signaling Networks Program, Sanford Burnham Prebys Medical Discovery Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
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668
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Kaushik S, Cuervo AM. AMPK-dependent phosphorylation of lipid droplet protein PLIN2 triggers its degradation by CMA. Autophagy 2016; 12:432-8. [PMID: 26902588 DOI: 10.1080/15548627.2015.1124226] [Citation(s) in RCA: 159] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Lipids stored in lipid droplets are hydrolyzed via either cytosolic lipases or a selective form of macroautophagy known as lipophagy. We recently demonstrated that chaperone-mediated autophagy (CMA) is required for the initiation of lipolysis by either of these independent lipolytic pathways. CMA selectively degrades the lipid droplet proteins perilipins (PLIN) 2 and 3 from the lipid droplet surface, thus, facilitating the recruitment of cytosolic lipases and autophagy effector proteins to the lipid droplets. PLIN2 phosphorylation was observed upon induction of lipolysis, but the phosphorylating kinase and the relation of this phosphorylation with CMA of PLIN2 remained unknown. Here, we report that phosphorylation of PLIN2 is dependent on AMPK and occurs after the interaction of PLIN2 with the CMA chaperone HSPA8/Hsc70. Our results highlight a role for posttranslational modifications in priming proteins to be amenable for degradation by CMA.
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Affiliation(s)
- Susmita Kaushik
- a Department of Developmental and Molecular Biology and Institute for Aging Studies, Albert Einstein College of Medicine , Bronx , NY USA
| | - Ana Maria Cuervo
- a Department of Developmental and Molecular Biology and Institute for Aging Studies, Albert Einstein College of Medicine , Bronx , NY USA
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669
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Vlahakis A, Debnath J. The Interconnections between Autophagy and Integrin-Mediated Cell Adhesion. J Mol Biol 2016; 429:515-530. [PMID: 27932295 DOI: 10.1016/j.jmb.2016.11.027] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 11/27/2016] [Accepted: 11/29/2016] [Indexed: 12/25/2022]
Abstract
Autophagy is a cellular degradation process integral for promoting cellular adaptation during metabolic stress while also functioning as a cellular homeostatic mechanism. Mounting evidence also demonstrates that autophagy is induced upon loss of integrin-mediated cell attachments to the surrounding extracellular matrix (ECM). Analogous to its established cytoprotective role during nutrient starvation, autophagy protects cells from detachment-induced cell death, termed anoikis. Here, we review the significance of autophagy as an anoikis resistance pathway, focusing on the intracellular signals associated with integrins that modulate the autophagy response and dictate the balance between cell death and survival following loss of cell-matrix contact. In addition, we highlight recent studies demonstrating that autophagy functions in the upstream regulation of integrin-mediated cell adhesion via the control of focal adhesion remodeling, and discuss how these emerging interconnections between integrin-mediated adhesion pathways and autophagy influence cancer progression and metastasis.
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Affiliation(s)
- Ariadne Vlahakis
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jayanta Debnath
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA 94143, USA.
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670
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Li Z, Schulze RJ, Weller SG, Krueger EW, Schott MB, Zhang X, Casey CA, Liu J, Stöckli J, James DE, McNiven MA. A novel Rab10-EHBP1-EHD2 complex essential for the autophagic engulfment of lipid droplets. SCIENCE ADVANCES 2016; 2:e1601470. [PMID: 28028537 PMCID: PMC5161429 DOI: 10.1126/sciadv.1601470] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 11/15/2016] [Indexed: 05/15/2023]
Abstract
The autophagic digestion of lipid droplets (LDs) through lipophagy is an essential process by which most cells catabolize lipids as an energy source. However, the cellular machinery used for the envelopment of LDs during autophagy is poorly understood. We report a novel function for a small Rab guanosine triphosphatase (GTPase) in the recruitment of adaptors required for the engulfment of LDs by the growing autophagosome. In hepatocytes stimulated to undergo autophagy, Rab10 activity is amplified significantly, concomitant with its increased recruitment to nascent autophagic membranes at the LD surface. Disruption of Rab10 function by small interfering RNA knockdown or expression of a GTPase-defective variant leads to LD accumulation. Finally, Rab10 activation during autophagy is essential for LC3 recruitment to the autophagosome and stimulates its increased association with the adaptor protein EHBP1 (EH domain binding protein 1) and the membrane-deforming adenosine triphosphatase EHD2 (EH domain containing 2) that, together, are essential in driving the activated "engulfment" of LDs during lipophagy in hepatocytes.
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Affiliation(s)
- Zhipeng Li
- Biochemistry and Molecular Biology Program, Mayo Graduate School, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Ryan J. Schulze
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
- Corresponding author. (M.A.M.); (R.J.S.)
| | - Shaun G. Weller
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Eugene W. Krueger
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Micah B. Schott
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
| | - Xiaodong Zhang
- Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, 13400 E Shea Boulevard, Scottsdale, AZ 85259, USA
| | - Carol A. Casey
- Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Jun Liu
- Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, 13400 E Shea Boulevard, Scottsdale, AZ 85259, USA
| | - Jacqueline Stöckli
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - David E. James
- Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
- Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Mark A. McNiven
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
- Corresponding author. (M.A.M.); (R.J.S.)
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671
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Xilouri M, Stefanis L. Chaperone mediated autophagy in aging: Starve to prosper. Ageing Res Rev 2016; 32:13-21. [PMID: 27484893 DOI: 10.1016/j.arr.2016.07.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 06/07/2016] [Accepted: 07/04/2016] [Indexed: 10/21/2022]
Abstract
The major lysosomal proteolytic pathways essential for maintaining proper cellular homeostasis are macroautophagy, chaperone-mediated autophagy (CMA) and microautophagy. What differentiates CMA from the other types of autophagy is the fact that it does not involve vesicle formation; the unique feature of this pathway is the selective targeting of substrate proteins containing a CMA-targeting motif and the direct translocation into the lysosomal lumen, through the aid of chaperones/co-chaperones localized both at the cytosol and the lysosomes. CMA operates at basal conditions in most mammalian cell models analyzed so far, but it is mostly activated in response to stressors, such as trophic deprivation or oxidative stress. The activity of CMA has been shown to decline with age and such decline, correlating with accumulation of damaged/oxidized/aggregated proteins, may contribute to tissue dysfunction and, possibly, neurodegeneration. Herein, we review the recent knowledge regarding the molecular components, regulation and physiology of the CMA pathway, the contribution of impaired CMA activity to poor cellular homeostasis and inefficient response to stress during aging, and discuss the therapeutic opportunities offered by the restoration of CMA-dependent proteolysis in age-associated degenerative diseases.
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672
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Assessment of Glycolytic Flux and Mitochondrial Respiration in the Course of Autophagic Responses. Methods Enzymol 2016; 588:155-170. [PMID: 28237099 DOI: 10.1016/bs.mie.2016.09.079] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Autophagy is an evolutionarily conserved process that mediates prominent homeostatic functions, both at the cellular and organismal level. Indeed, baseline autophagy not only ensures the disposal of cytoplasmic entities that may become cytotoxic upon accumulation, but also contributes to the maintenance of metabolic fitness in physiological conditions. Likewise, autophagy plays a fundamental role in the cellular and organismal adaptation to homeostatic perturbations of metabolic, physical, or chemical nature. Thus, the molecular machinery for autophagy is functionally regulated by a broad panel of sensors that detect indicators of metabolic homeostasis. Moreover, increases in autophagic flux have a direct impact on core metabolic circuitries including (but not limited to) glycolysis and mitochondrial respiration. Here, we detail a simple methodological approach to monitor these two processes in cultured cancer cells that mount a proficient autophagic response to stress.
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673
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A systems study reveals concurrent activation of AMPK and mTOR by amino acids. Nat Commun 2016; 7:13254. [PMID: 27869123 PMCID: PMC5121333 DOI: 10.1038/ncomms13254] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 09/13/2016] [Indexed: 12/17/2022] Open
Abstract
Amino acids (aa) are not only building blocks for proteins, but also signalling molecules, with the mammalian target of rapamycin complex 1 (mTORC1) acting as a key mediator. However, little is known about whether aa, independently of mTORC1, activate other kinases of the mTOR signalling network. To delineate aa-stimulated mTOR network dynamics, we here combine a computational–experimental approach with text mining-enhanced quantitative proteomics. We report that AMP-activated protein kinase (AMPK), phosphatidylinositide 3-kinase (PI3K) and mTOR complex 2 (mTORC2) are acutely activated by aa-readdition in an mTORC1-independent manner. AMPK activation by aa is mediated by Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ). In response, AMPK impinges on the autophagy regulators Unc-51-like kinase-1 (ULK1) and c-Jun. AMPK is widely recognized as an mTORC1 antagonist that is activated by starvation. We find that aa acutely activate AMPK concurrently with mTOR. We show that AMPK under aa sufficiency acts to sustain autophagy. This may be required to maintain protein homoeostasis and deliver metabolite intermediates for biosynthetic processes. mTORC1 is known to mediate the signalling activity of amino acids. Here, the authors combine modelling with experiments and find that amino acids acutely stimulate mTORC2, IRS/PI3K and AMPK, independently of mTORC1. AMPK activation through CaMKKβ sustains autophagy under non-starvation conditions.
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674
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Guedouari H, Daigle T, Scorrano L, Hebert-Chatelain E. Sirtuin 5 protects mitochondria from fragmentation and degradation during starvation. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:169-176. [PMID: 28340937 DOI: 10.1016/j.bbamcr.2016.10.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/13/2016] [Accepted: 10/25/2016] [Indexed: 01/09/2023]
Abstract
During starvation, intra-mitochondrial sirtuins, NAD+ sensitive deacylating enzymes that modulate metabolic homeostasis and survival, directly adjust mitochondrial function to nutrient availability; concomitantly, mitochondria elongate to escape autophagic degradation. However, whether sirtuins also impinge on mitochondrial dynamics is still uncharacterized. Here we show that the mitochondrial Sirtuin 5 (Sirt5) is essential for starvation induced mitochondrial elongation. Deletion of Sirt5 in mouse embryonic fibroblasts increased levels of mitochondrial dynamics of 51kDa protein and mitochondrial fission protein 1, leading to mitochondrial accumulation of the pro-fission dynamin related protein 1 and to mitochondrial fragmentation. During starvation, Sirt5 deletion blunted mitochondrial elongation, resulting in increased mitophagy. Our results indicate that starvation induced mitochondrial elongation and evasion from autophagic degradation requires the energy sensor Sirt5.
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Affiliation(s)
- Hala Guedouari
- Department of Biology, University of Moncton, NB, Canada
| | - Tanya Daigle
- Department of Biology, University of Moncton, NB, Canada
| | - Luca Scorrano
- Dulbecco Telethon Institute, Venetian Institute of Molecular Medicine, Padua, Italy; Department of Biology, University of Padua, Italy
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675
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Sonner JK, Deumelandt K, Ott M, Thomé CM, Rauschenbach KJ, Schulz S, Munteanu B, Mohapatra S, Adam I, Hofer AC, Feuerer M, Opitz CA, Hopf C, Wick W, Platten M. The stress kinase GCN2 does not mediate suppression of antitumor T cell responses by tryptophan catabolism in experimental melanomas. Oncoimmunology 2016; 5:e1240858. [PMID: 28123877 DOI: 10.1080/2162402x.2016.1240858] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 09/10/2016] [Accepted: 09/19/2016] [Indexed: 10/20/2022] Open
Abstract
Tryptophan metabolism is a key process that shapes the immunosuppressive tumor microenvironment. The two rate-limiting enzymes that mediate tryptophan depletion, indoleamine-2,3-dioxygenase (IDO) and tryptophan-2,3-dioxygenase (TDO), have moved into the focus of research and inhibitors targeting IDO and TDO have entered clinical trials. Local tryptophan depletion is generally viewed as the crucial immunosuppressive mechanism. In T cells, the kinase general control non-derepressible 2 (GCN2) has been identified as a molecular sensor of tryptophan deprivation. GCN2 activation by tryptophan depletion induces apoptosis and mitigates T cell proliferation. Here, we investigated whether GCN2 attenuates tumor rejection in experimental B16 melanoma using T cell-specific Gcn2 knockout mice. Our data demonstrate that GCN2 in T cells did not affect immunity to B16 tumors even when animals were treated with antibodies targeting cytotoxic T lymphocyte antigen-4 (CTLA4). GCN2-deficient gp100 TCR-transgenic T cells were equally effective as wild-type pmel T cells against gp100-expressing B16 melanomas after adoptive transfer and gp100 peptide vaccination. Even augmentation of tumoral tryptophan metabolism in B16 tumors by lentiviral overexpression of Tdo did not differentially affect GCN2-proficient vs. GCN2-deficient T cells in vivo. Importantly, GCN2 target genes were not upregulated in tumor-infiltrating T cells. MALDI-TOF MS imaging of B16 melanomas demonstrated maintenance of intratumoral tryptophan levels despite high tryptophan turnover, which prohibits a drop in tryptophan sufficient to activate GCN2 in tumor-infiltrating T cells. In conclusion, our results do not suggest that suppression of antitumor immune responses by tryptophan metabolism is driven by local tryptophan depletion and subsequent GCN2-mediated T cell anergy.
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Affiliation(s)
- Jana K Sonner
- DKTK CCU Neuroimmunology and Brain Tumor Immunology, DKFZ , Heidelberg, Germany
| | - Katrin Deumelandt
- DKTK CCU Neuroimmunology and Brain Tumor Immunology, DKFZ , Heidelberg, Germany
| | - Martina Ott
- DKTK CCU Neuroimmunology and Brain Tumor Immunology, DKFZ , Heidelberg, Germany
| | | | | | - Sandra Schulz
- Centre for Applied Research "Applied Biomedical Mass Spectrometry" (ABIMAS), Hochschule Mannheim , Mannheim, Germany
| | - Bogdan Munteanu
- Centre for Applied Research "Applied Biomedical Mass Spectrometry" (ABIMAS), Hochschule Mannheim , Mannheim, Germany
| | - Soumya Mohapatra
- Junior Group Brain Cancer Metabolism, DKFZ , Heidelberg, Germany
| | - Isabell Adam
- Junior Group Brain Cancer Metabolism, DKFZ , Heidelberg, Germany
| | | | - Markus Feuerer
- Research Group Immune Tolerance, DKFZ , Heidelberg, Germany
| | - Christiane A Opitz
- Junior Group Brain Cancer Metabolism, DKFZ, Heidelberg, Germany; Department of Neurology and National Center of Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany
| | - Carsten Hopf
- Centre for Applied Research "Applied Biomedical Mass Spectrometry" (ABIMAS), Hochschule Mannheim , Mannheim, Germany
| | - Wolfgang Wick
- DKTK CCU Neurooncology, DKFZ, Heidelberg, Germany; Department of Neurology and National Center of Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany
| | - Michael Platten
- DKTK CCU Neuroimmunology and Brain Tumor Immunology, DKFZ, Heidelberg, Germany; Department of Neurology and National Center of Tumor Diseases, University Hospital Heidelberg, Heidelberg, Germany; Department of Neurology, University Medical Center Mannheim, Heidelberg University, Mannheim, Germany
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676
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Activating autophagy to potentiate immunogenic chemotherapy and radiation therapy. Nat Rev Clin Oncol 2016; 14:247-258. [PMID: 27845767 DOI: 10.1038/nrclinonc.2016.183] [Citation(s) in RCA: 237] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Autophagy is fundamental to the maintenance of intracellular homeostasis in virtually all human cells. Accordingly, defective autophagy predisposes healthy cells to undergoing malignant transformation. By contrast, malignant cells are able to harness autophagy to thrive, despite adverse microenvironmental conditions, and to resist therapeutic challenges. Thus, inhibition of autophagy has been proposed as a strategy to kill cancer cells or sensitize them to therapy; however, autophagy is also critical for optimal immune function, and mediates cell-extrinsic homeostatic effects owing to its central role in danger signalling by neoplastic cells responding to immunogenic chemotherapy and/or radiation therapy. In this Perspective, we discuss accumulating preclinical and clinical evidence in support of the all-too-often dismissed possibility that activating autophagy might be a relevant clinical objective that enables an increase in the effectiveness of immunogenic chemotherapy and/or radiation therapy.
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677
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Muratore KA, Grundhofer HM, Arriaga EA. Capillary Electrophoresis with Laser-Induced Fluorescent Detection of Immunolabeled Individual Autophagy Organelles Isolated from Liver Tissue. Anal Chem 2016; 88:11691-11698. [PMID: 27783895 DOI: 10.1021/acs.analchem.6b03270] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Macroautophagy is a cellular degradation process responsible for the clearance of excess intracellular cargo. Existing methods for bulk quantification of autophagy rely on organelle markers that bind to multiple autophagy organelle types, making it difficult to tease apart the subcellular mechanisms implicated in autophagy dysfunction in liver and other pathologies. To address this issue, methods based on individual organelle measurements are needed. Capillary electrophoresis with laser-induced fluorescent detection (CE-LIF) was previously used to count and determine properties of individual autophagy organelles isolated from an LC3-GFP expressing cell line, but has never been used on autophagy organelles originating from a tissue sample. Here, we used DyLight488-labeled anti-LC3 antibodies to label endogenous LC3 present on organelles isolated from murine liver tissue prior to CE-LIF analysis. We evaluated the ability of this method to detect changes in a known model system of altered autophagy, as well as confirmed the specificity and reproducibility of the antibody in the labeling of autophagy organelles from liver tissue. This is both the first demonstration of CE-LIF to analyze individual organelles labeled with fluorophore-conjugated antibodies, and the first application of individual organelle CE-LIF to measure the properties of autophagy organelles isolated from tissue. The observations described here demonstrate that CE-LIF of immunolabeled autophagy organelles is a powerful technique useful to investigate the complexity of autophagy in any tissue sample of interest.
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Affiliation(s)
- Katherine A Muratore
- Department of Biochemistry, Molecular Biology, and Biophysics and ‡Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Heather M Grundhofer
- Department of Biochemistry, Molecular Biology, and Biophysics and ‡Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
| | - Edgar A Arriaga
- Department of Biochemistry, Molecular Biology, and Biophysics and ‡Department of Chemistry, University of Minnesota , Minneapolis, Minnesota 55455, United States
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678
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Di Domenico F, Tramutola A, Perluigi M. Cathepsin D as a therapeutic target in Alzheimer's disease. Expert Opin Ther Targets 2016; 20:1393-1395. [PMID: 27805462 DOI: 10.1080/14728222.2016.1252334] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Fabio Di Domenico
- a Department of Biochemical Sciences , Sapienza University of Rome , Rome , Italy
| | - Antonella Tramutola
- a Department of Biochemical Sciences , Sapienza University of Rome , Rome , Italy
| | - Marzia Perluigi
- a Department of Biochemical Sciences , Sapienza University of Rome , Rome , Italy
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679
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Hubbs AF, Fluharty KL, Edwards RJ, Barnabei JL, Grantham JT, Palmer SM, Kelly F, Sargent LM, Reynolds SH, Mercer RR, Goravanahally MP, Kashon ML, Honaker JC, Jackson MC, Cumpston AM, Goldsmith WT, McKinney W, Fedan JS, Battelli LA, Munro T, Bucklew-Moyers W, McKinstry K, Schwegler-Berry D, Friend S, Knepp AK, Smith SL, Sriram K. Accumulation of Ubiquitin and Sequestosome-1 Implicate Protein Damage in Diacetyl-Induced Cytotoxicity. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2887-2908. [PMID: 27643531 PMCID: PMC5222965 DOI: 10.1016/j.ajpath.2016.07.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 07/09/2016] [Accepted: 07/21/2016] [Indexed: 01/12/2023]
Abstract
Inhaled diacetyl vapors are associated with flavorings-related lung disease, a potentially fatal airway disease. The reactive α-dicarbonyl group in diacetyl causes protein damage in vitro. Dicarbonyl/l-xylulose reductase (DCXR) metabolizes diacetyl into acetoin, which lacks this α-dicarbonyl group. To investigate the hypothesis that flavorings-related lung disease is caused by in vivo protein damage, we correlated diacetyl-induced airway damage in mice with immunofluorescence for markers of protein turnover and autophagy. Western immunoblots identified shifts in ubiquitin pools. Diacetyl inhalation caused dose-dependent increases in bronchial epithelial cells with puncta of both total ubiquitin and K63-ubiquitin, central mediators of protein turnover. This response was greater in Dcxr-knockout mice than in wild-type controls inhaling 200 ppm diacetyl, further implicating the α-dicarbonyl group in protein damage. Western immunoblots demonstrated decreased free ubiquitin in airway-enriched fractions. Transmission electron microscopy and colocalization of ubiquitin-positive puncta with lysosomal-associated membrane proteins 1 and 2 and with the multifunctional scaffolding protein sequestosome-1 (SQSTM1/p62) confirmed autophagy. Surprisingly, immunoreactive SQSTM1 also accumulated in the olfactory bulb of the brain. Olfactory bulb SQSTM1 often congregated in activated microglial cells that also contained olfactory marker protein, indicating neuronophagia within the olfactory bulb. This suggests the possibility that SQSTM1 or damaged proteins may be transported from the nose to the brain. Together, these findings strongly implicate widespread protein damage in the etiology of flavorings-related lung disease.
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Affiliation(s)
- Ann F Hubbs
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia.
| | - Kara L Fluharty
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Rebekah J Edwards
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Jamie L Barnabei
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; College of Veterinary Medicine, University of Georgia, Athens, Georgia
| | - John T Grantham
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; School of Medicine, West Virginia University, Morgantown, West Virginia
| | - Scott M Palmer
- Duke University School of Medicine, Durham, North Carolina
| | - Francine Kelly
- Duke University School of Medicine, Durham, North Carolina
| | - Linda M Sargent
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Steven H Reynolds
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Robert R Mercer
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Madhusudan P Goravanahally
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Centers for Neuroscience, West Virginia University, Morgantown, West Virginia
| | - Michael L Kashon
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - John C Honaker
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Mark C Jackson
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Amy M Cumpston
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - William T Goldsmith
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Walter McKinney
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Jeffrey S Fedan
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Lori A Battelli
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Tiffany Munro
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Winnie Bucklew-Moyers
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Kimberly McKinstry
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Diane Schwegler-Berry
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Sherri Friend
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
| | - Alycia K Knepp
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Samantha L Smith
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia; Department of Forensic and Investigative Science, West Virginia University, Morgantown, West Virginia
| | - Krishnan Sriram
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, West Virginia
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680
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Enrich C, Rentero C, Grewal T. Annexin A6 in the liver: From the endocytic compartment to cellular physiology. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:933-946. [PMID: 27984093 DOI: 10.1016/j.bbamcr.2016.10.017] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 10/25/2016] [Accepted: 10/26/2016] [Indexed: 12/15/2022]
Abstract
Annexin A6 (AnxA6) belongs to the conserved annexin family - a group of Ca2+-dependent membrane binding proteins. AnxA6 is the largest of all annexins and highly expressed in smooth muscle, hepatocytes, endothelial cells and cardiomyocytes. Upon activation, AnxA6 binds to negatively charged phospholipids in a wide range of intracellular localizations, in particular the plasma membrane, late endosomes/pre-lysosomes, but also synaptic vesicles and sarcolemma. In these cellular sites, AnxA6 is believed to contribute to the organization of membrane microdomains, such as cholesterol-rich lipid rafts and confer multiple regulatory functions, ranging from vesicle fusion, endocytosis and exocytosis to programmed cell death and muscle contraction. Growing evidence supports that Ca2+ and Ca2+-binding proteins control endocytosis and autophagy. Their regulatory role seems to operate at the level of the signalling pathways that initiate autophagy or at later stages, when autophagosomes fuse with endolysosomal compartments. The convergence of the autophagic and endocytic vesicles to lysosomes shares several features that depend on Ca2+ originating from lysosomes/late endosomes and seems to depend on proteins that are subsequently activated by this cation. However, the involvement of Ca2+ and its effector proteins in these autophagic and endocytic stages still remains poorly understood. Although AnxA6 makes up almost 0.25% of total protein in the liver, little is known about its function in hepatocytes. Within the endocytic route, we identified AnxA6 in endosomes and autophagosomes of hepatocytes. Hence, AnxA6 and possibly other annexins might represent new Ca2+ effectors that regulate converging steps of autophagy and endocytic trafficking in hepatocytes. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- Carlos Enrich
- Departament de Biomedicina, Unitat de Biologia Cellular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain.
| | - Carles Rentero
- Departament de Biomedicina, Unitat de Biologia Cellular, Centre de Recerca Biomèdica CELLEX, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
| | - Thomas Grewal
- Faculty of Pharmacy A15, University of Sydney, Sydney, NSW 2006, Australia
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681
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Guerrier S, Plattner H, Richardson E, Dacks JB, Turkewitz AP. An evolutionary balance: conservation vs innovation in ciliate membrane trafficking. Traffic 2016; 18:18-28. [PMID: 27696651 DOI: 10.1111/tra.12450] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/20/2016] [Accepted: 09/20/2016] [Indexed: 12/15/2022]
Abstract
As most of eukaryotic diversity lies in single-celled protists, they represent unique opportunities to ask questions about the balance of conservation and innovation in cell biological features. Among free-living protists the ciliates offer ease of culturing, a rich array of experimental approaches, and versatile molecular tools, particularly in Tetrahymena thermophila and Paramecium tetraurelia. These attributes have been exploited by researchers to analyze a wealth of cellular structures in these large and complex cells. This mini-review focuses on 3 aspects of ciliate membrane dynamics, all linked with endolysosomal trafficking. First is nutrition based on phagocytosis and maturation of food vacuoles. Secondly, we discuss regulated exocytosis from vesicles that have features of both dense core secretory granules but also lysosome-related organelles. The third topic is the targeting, breakdown and resorption of parental nuclei in mating partners. For all 3 phenomena, it is clear that elements of the canonical membrane-trafficking system have been retained and in some cases repurposed. In addition, there is evidence that recently evolved, lineage-specific proteins provide determinants in these pathways.
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Affiliation(s)
| | - Helmut Plattner
- Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Joel B Dacks
- Department of Cell Biology, University of Alberta, Canada
| | - Aaron P Turkewitz
- Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, Illinois
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682
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Liu Y, Muñoz N, Tsai AC, Logan TM, Ma T. Metabolic Reconfiguration Supports Reacquisition of Primitive Phenotype in Human Mesenchymal Stem Cell Aggregates. Stem Cells 2016; 35:398-410. [DOI: 10.1002/stem.2510] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/16/2016] [Accepted: 08/21/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Yijun Liu
- Department of Chemical and Biomedical Engineering; Florida State University; Tallahassee Florida USA
| | - Nathalie Muñoz
- Graduate Program in Molecular Biophysics, Florida State University; Tallahassee Florida USA
| | - Ang-Chen Tsai
- Department of Chemical and Biomedical Engineering; Florida State University; Tallahassee Florida USA
| | - Timothy M. Logan
- Graduate Program in Molecular Biophysics, Florida State University; Tallahassee Florida USA
- Department of Chemistry and Biochemistry; Florida State University; Tallahassee Florida USA
| | - Teng Ma
- Department of Chemical and Biomedical Engineering; Florida State University; Tallahassee Florida USA
- Graduate Program in Molecular Biophysics, Florida State University; Tallahassee Florida USA
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683
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Starobinets H, Ye J, Broz M, Barry K, Goldsmith J, Marsh T, Rostker F, Krummel M, Debnath J. Antitumor adaptive immunity remains intact following inhibition of autophagy and antimalarial treatment. J Clin Invest 2016; 126:4417-4429. [PMID: 27775547 DOI: 10.1172/jci85705] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 09/15/2016] [Indexed: 01/05/2023] Open
Abstract
The rising success of cancer immunotherapy has produced immense interest in defining the clinical contexts that may benefit from this therapeutic approach. To this end, there is a need to ascertain how the therapeutic modulation of intrinsic cancer cell programs influences the anticancer immune response. For example, the role of autophagy as a tumor cell survival and metabolic fitness pathway is being therapeutically targeted in ongoing clinical trials that combine cancer therapies with antimalarial drugs for the treatment of a broad spectrum of cancers, many of which will likely benefit from immunotherapy. However, our current understanding of the interplay between autophagy and the immune response remains incomplete. Here, we have evaluated how autophagy inhibition impacts the antitumor immune response in immune-competent mouse models of melanoma and mammary cancer. We observed equivalent levels of T cell infiltration and function within autophagy-competent and -deficient tumors, even upon treatment with the anthracycline chemotherapeutic doxorubicin. Similarly, we found equivalent T cell responses upon systemic treatment of tumor-bearing mice with antimalarial drugs. Our findings demonstrate that antitumor adaptive immunity is not adversely impaired by autophagy inhibition in these models, allowing for the future possibility of combining autophagy inhibitors with immunotherapy in certain clinical contexts.
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684
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Abstract
The lysosome has long been viewed as the recycling center of the cell. However, recent discoveries have challenged this simple view and have established a central role of the lysosome in nutrient-dependent signal transduction. The degradative role of the lysosome and its newly discovered signaling functions are not in conflict but rather cooperate extensively to mediate fundamental cellular activities such as nutrient sensing, metabolic adaptation, and quality control of proteins and organelles. Moreover, lysosome-based signaling and degradation are subject to reciprocal regulation. Transcriptional programs of increasing complexity control the biogenesis, composition, and abundance of lysosomes and fine-tune their activity to match the evolving needs of the cell. Alterations in these essential activities are, not surprisingly, central to the pathophysiology of an ever-expanding spectrum of conditions, including storage disorders, neurodegenerative diseases, and cancer. Thus, unraveling the functions of this fascinating organelle will contribute to our understanding of the fundamental logic of metabolic organization and will point to novel therapeutic avenues in several human diseases.
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Affiliation(s)
- Rushika M Perera
- Department of Anatomy and Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, California 94143;
| | - Roberto Zoncu
- Department of Molecular and Cellular Biology and Paul F. Glenn Center for Aging Research, University of California, Berkeley, California 94720;
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685
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Guebel DV, Torres NV. Sexual Dimorphism and Aging in the Human Hyppocampus: Identification, Validation, and Impact of Differentially Expressed Genes by Factorial Microarray and Network Analysis. Front Aging Neurosci 2016; 8:229. [PMID: 27761111 PMCID: PMC5050216 DOI: 10.3389/fnagi.2016.00229] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 09/14/2016] [Indexed: 01/09/2023] Open
Abstract
Motivation: In the brain of elderly-healthy individuals, the effects of sexual dimorphism and those due to normal aging appear overlapped. Discrimination of these two dimensions would powerfully contribute to a better understanding of the etiology of some neurodegenerative diseases, such as “sporadic” Alzheimer. Methods: Following a system biology approach, top-down and bottom-up strategies were combined. First, public transcriptome data corresponding to the transition from adulthood to the aging stage in normal, human hippocampus were analyzed through an optimized microarray post-processing (Q-GDEMAR method) together with a proper experimental design (full factorial analysis). Second, the identified genes were placed in context by building compatible networks. The subsequent ontology analyses carried out on these networks clarify the main functionalities involved. Results: Noticeably we could identify large sets of genes according to three groups: those that exclusively depend on the sex, those that exclusively depend on the age, and those that depend on the particular combinations of sex and age (interaction). The genes identified were validated against three independent sources (a proteomic study of aging, a senescence database, and a mitochondrial genetic database). We arrived to several new inferences about the biological functions compromised during aging in two ways: by taking into account the sex-independent effects of aging, and considering the interaction between age and sex where pertinent. In particular, we discuss the impact of our findings on the functions of mitochondria, autophagy, mitophagia, and microRNAs. Conclusions: The evidence obtained herein supports the occurrence of significant neurobiological differences in the hippocampus, not only between adult and elderly individuals, but between old-healthy women and old-healthy men. Hence, to obtain realistic results in further analysis of the transition from the normal aging to incipient Alzheimer, the features derived from the sexual dimorphism in hippocampus should be explicitly considered.
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Affiliation(s)
- Daniel V Guebel
- Biotechnology Counselling ServicesBuenos Aires, Argentina; Systems Biology and Mathematical Modelling Group, Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Facultad de Ciencias, Universidad de La LagunaSan Cristóbal de La Laguna, España
| | - Néstor V Torres
- Systems Biology and Mathematical Modelling Group, Departamento de Bioquímica, Microbiología, Biología Celular y Genética, Facultad de Ciencias, Universidad de La Laguna San Cristóbal de La Laguna, España
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686
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Martín-Acebes MA, Vázquez-Calvo Á, Saiz JC. Lipids and flaviviruses, present and future perspectives for the control of dengue, Zika, and West Nile viruses. Prog Lipid Res 2016; 64:123-137. [PMID: 27702593 DOI: 10.1016/j.plipres.2016.09.005] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 08/17/2016] [Accepted: 09/16/2016] [Indexed: 02/06/2023]
Abstract
Flaviviruses are emerging arthropod-borne pathogens that cause life-threatening diseases such as yellow fever, dengue, West Nile encephalitis, tick-borne encephalitis, Kyasanur Forest disease, tick-borne encephalitis, or Zika disease. This viral genus groups >50 viral species of small enveloped plus strand RNA virus that are phylogenetically closely related to hepatitis C virus. Importantly, the flavivirus life cycle is intimately associated to host cell lipids. Along this line, flaviviruses rearrange intracellular membranes from the endoplasmic-reticulum of the infected cells to develop adequate platforms for viral replication and particle biogenesis. Moreover, flaviviruses dramatically orchestrate a profound reorganization of the host cell lipid metabolism to create a favorable environment for viral multiplication. Consistently, recent work has shown the importance of specific lipid classes in flavivirus infections. For instances, fatty acid synthesis is linked to viral replication, phosphatidylserine and phosphatidylethanolamine are involved on the entry of flaviviruses, sphingolipids (ceramide and sphingomyelin) play a key role on virus assembly and pathogenesis, and cholesterol is essential for innate immunity evasion in flavivirus-infected cells. Here, we revise the current knowledge on the interactions of the flaviviruses with the cellular lipid metabolism to identify potential targets for future antiviral development aimed to combat these relevant health-threatening pathogens.
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Affiliation(s)
- Miguel A Martín-Acebes
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de A Coruña km 7.5, 28040 Madrid, Spain.
| | - Ángela Vázquez-Calvo
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de A Coruña km 7.5, 28040 Madrid, Spain
| | - Juan-Carlos Saiz
- Department of Biotechnology, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Carretera de A Coruña km 7.5, 28040 Madrid, Spain
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687
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Esner M, Graifer D, Lleonart ME, Lyakhovich A. Targeting cancer cells through antibiotics-induced mitochondrial dysfunction requires autophagy inhibition. Cancer Lett 2016; 384:60-69. [PMID: 27693455 DOI: 10.1016/j.canlet.2016.09.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 09/18/2016] [Accepted: 09/20/2016] [Indexed: 12/21/2022]
Abstract
A significant part of current research studies utilizes various cellular models which imply specific antibiotics-containing media as well as antibiotics used for clonal selection or promoter de/activation. With the great success of developing such tools, mitochondria, once originated from bacteria, can be effectively targeted by antibiotics. For that reason, some studies propose antibiotics-targeting of mitochondria as part of anticancer therapy. Here, we have focused on the effects of various classes of antibiotics on mitochondria in cancer and non-cancer cells and demonlow mitochondrial membrane potential, reduced ATP production, altered morphology and lowered respiration rate which altogether suggested mitochondrial dysfunction (MDF). This was in parallel with increased level of reactive oxygen species (ROS) and decreased activity of mitochondrial respiration complexes. However, both survival and repopulation capacity of cancer cells was not significantly affected by the antibiotics, perhaps due to a glycolytic shift or activated autophagy. In turn, simultaneous inhibition of autophagy and treatment with antibiotics largely reduced tumorigenic properties of cancer cells suggesting potential strategy for anticancer therapy.
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Affiliation(s)
- Milan Esner
- Department of Histology and Embryology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Dmitry Graifer
- Novosibirsk State University, Novosibirsk, Pirogova 2, 630090, Russia
| | - Matilde E Lleonart
- Translational Research in Cancer Stem Cells, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain
| | - Alex Lyakhovich
- Translational Research in Cancer Stem Cells, Vall d'Hebron Institut de Recerca (VHIR), Barcelona, Spain; Novosibirsk Institute of Molecular Biology and Biophysics, Novosibirsk, Russia; ICRC-FNUSA, International Clinical Research Center and St. Anne's University Hospital Brno, Czech Republic.
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688
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Clark CA, Gupta HB, Sareddy G, Pandeswara S, Lao S, Yuan B, Drerup JM, Padron A, Conejo-Garcia J, Murthy K, Liu Y, Turk MJ, Thedieck K, Hurez V, Li R, Vadlamudi R, Curiel TJ. Tumor-Intrinsic PD-L1 Signals Regulate Cell Growth, Pathogenesis, and Autophagy in Ovarian Cancer and Melanoma. Cancer Res 2016; 76:6964-6974. [PMID: 27671674 DOI: 10.1158/0008-5472.can-16-0258] [Citation(s) in RCA: 277] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 09/16/2016] [Accepted: 09/16/2016] [Indexed: 01/09/2023]
Abstract
PD-L1 antibodies produce efficacious clinical responses in diverse human cancers, but the basis for their effects remains unclear, leaving a gap in the understanding of how to rationally leverage therapeutic activity. PD-L1 is widely expressed in tumor cells, but its contributions to tumor pathogenicity are incompletely understood. In this study, we evaluated the hypothesis that PD-L1 exerts tumor cell-intrinsic signals that are critical for pathogenesis. Using RNAi methodology, we attenuated PD-L1 in the murine ovarian cell line ID8agg and the melanoma cell line B16 (termed PD-L1lo cells), which express basal PD-L1. We observed that PD-L1lo cells proliferated more weakly than control cells in vitro As expected, PD-L1lo cells formed tumors in immunocompetent mice relatively more slowly, but unexpectedly, they also formed tumors more slowly in immunodeficient NSG mice. RNA sequencing analysis identified a number of genes involved in autophagy and mTOR signaling that were affected by PD-L1 expression. In support of a functional role, PD-L1 attenuation augmented autophagy and blunted the ability of autophagy inhibitors to limit proliferation in vitro and in vivo in NSG mice. PD-L1 attenuation also reduced mTORC1 activity and augmented the antiproliferative effects of the mTORC1 inhibitor rapamycin. PD-L1lo cells were also relatively deficient in metastasis to the lung, and we found that anti-PD-L1 administration could block tumor cell growth and metastasis in NSG mice. This therapeutic effect was observed with B16 cells but not ID8agg cells, illustrating tumor- or compartmental-specific effects in the therapeutic setting. Overall, our findings extend understanding of PD-L1 functions, illustrate nonimmune effects of anti-PD-L1 immunotherapy, and suggest broader uses for PD-L1 as a biomarker for assessing cancer therapeutic responses. Cancer Res; 76(23); 6964-74. ©2016 AACR.
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Affiliation(s)
- Curtis A Clark
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center, San Antonio, Texas.,Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Harshita B Gupta
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Gangadhara Sareddy
- Cancer Therapy & Research Center, University of Texas Health Science Center, San Antonio, Texas.,Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Srilakshmi Pandeswara
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Shunhua Lao
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Bin Yuan
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas.,Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Justin M Drerup
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center, San Antonio, Texas.,Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Alvaro Padron
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - José Conejo-Garcia
- Tumor Microenvironment and Metastasis Program, The Wistar Institute, Philadelphia, Pennsylvania
| | - Kruthi Murthy
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center, San Antonio, Texas.,Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Yang Liu
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas.,Xiangya School of Medicine, Central South University, Changsha, Hunan, PR China
| | - Mary Jo Turk
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Kathrin Thedieck
- Department of Pediatrics, Center for Liver, Digestive and Metabolic Diseases, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands and Department for Neuroscience, School of Medicine and Health Sciences, University Oldenburg, Oldenburg, Germany
| | - Vincent Hurez
- Department of Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Rong Li
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center, San Antonio, Texas.,Cancer Therapy & Research Center, University of Texas Health Science Center, San Antonio, Texas.,Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, Texas
| | - Ratna Vadlamudi
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center, San Antonio, Texas.,Cancer Therapy & Research Center, University of Texas Health Science Center, San Antonio, Texas.,Department of Obstetrics and Gynecology, University of Texas Health Science Center, San Antonio, Texas
| | - Tyler J Curiel
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center, San Antonio, Texas. .,Department of Medicine, University of Texas Health Science Center, San Antonio, Texas.,Cancer Therapy & Research Center, University of Texas Health Science Center, San Antonio, Texas
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689
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Abstract
Autophagy, a pathway for lysosomal-mediated cellular degradation, has recently been described as a regulator of cell migration. Although the molecular mechanisms underlying autophagy-dependent motility are only beginning to emerge, new work demonstrates that selective autophagy mediated by the autophagy cargo receptor, NBR1, specifically promotes the dynamic turnover of integrin-based focal adhesion sites during motility. Here, we discuss the detailed mechanisms through which NBR1-dependent selective autophagy supports focal adhesion remodeling, and we describe the interconnections between this pathway and other established regulators of focal adhesion turnover, such as microtubules. We also highlight studies that examine the contribution of autophagy to selective degradation of proteins that mediate cellular tension and to integrin trafficking; these findings hint at further roles for autophagy in supporting adhesion and migration. Given the recently appreciated importance of selective autophagy in diverse cellular processes, we propose that further investigation into autophagy-mediated focal adhesion turnover will not only shed light onto how focal adhesions are regulated but will also unveil new mechanisms regulating selective autophagy.
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Affiliation(s)
- Candia M Kenific
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94143, USA Biomedical Sciences Graduate Program, University of California San Francisco, San Francisco, CA 94143, USA
| | - Torsten Wittmann
- Department of Cell and Tissue Biology, University of California San Francisco, San Francisco, CA 94143, USA
| | - Jayanta Debnath
- Department of Pathology and Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA 94143, USA
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690
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Lashinger LM, O'Flanagan CH, Dunlap SM, Rasmussen AJ, Sweeney S, Guo JY, Lodi A, Tiziani S, White E, Hursting SD. Starving cancer from the outside and inside: separate and combined effects of calorie restriction and autophagy inhibition on Ras-driven tumors. Cancer Metab 2016; 4:18. [PMID: 27651895 PMCID: PMC5025535 DOI: 10.1186/s40170-016-0158-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 08/17/2016] [Indexed: 12/18/2022] Open
Abstract
Background Calorie restriction (CR) prevents obesity and exerts anticancer effects in many preclinical models. CR is also increasingly being used in cancer patients as a sensitizing strategy prior to chemotherapy regimens. While the beneficial effects of CR are widely accepted, the mechanisms through which CR affects tumor growth are incompletely understood. In many cell types, CR and other nutrient stressors can induce autophagy, which provides energy and metabolic substrates critical for cancer cell survival. We hypothesized that limiting extracellular and intracellular substrate availability by combining CR with autophagy inhibition would reduce tumor growth more effectively than either treatment alone. Results A 30 % CR diet, relative to control diet, in nude mice resulted in significant decreases in body fat, blood glucose, and serum insulin, insulin-like growth factor-1, and leptin levels concurrent with increased adiponectin levels. In a xenograft model in nude mice involving H-RasG12V-transformed immortal baby mouse kidney epithelial cells with (Atg5+/+) and without (Atg5−/−) autophagic capacity, the CR diet (relative to control diet) genetically induced autophagy inhibition and their combination, each reduced tumor development and growth. Final tumor volume was greatest for Atg5+/+ tumors in control-fed mice, intermediate for Atg5+/+ tumors in CR-fed mice and Atg5−/− tumors in control-fed mice, and lowest for Atg5−/− tumors in CR mice. In Atg5+/+ tumors, autophagic flux was increased in CR-fed relative to control-fed mice, suggesting that the prosurvival effects of autophagy induction may mitigate the tumor suppressive effects of CR. Metabolomic analyses of CR-fed, relative to control-fed, nude mice showed significant decreases in circulating glucose and amino acids and significant increases in ketones, indicating CR induced negative energy balance. Combining glucose deprivation with autophagy deficiency in Atg5−/− cells resulted in significantly reduced in vitro colony formation relative to glucose deprivation or autophagy deficiency alone. Conclusions Combined restriction of extracellular (via CR in vivo or glucose deprivation in vitro) and intracellular (via autophagy inhibition) sources of energy and nutrients suppresses Ras-driven tumor growth more effectively than either CR or autophagy deficiency alone. Interventions targeting both systemic energy balance and tumor-cell intrinsic autophagy may represent a novel and effective anticancer strategy.
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Affiliation(s)
- Laura M Lashinger
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723 USA
| | - Ciara H O'Flanagan
- Department of Nutrition, University of North Carolina, Chapel Hill, NC 27517 USA
| | - Sarah M Dunlap
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723 USA
| | - Audrey J Rasmussen
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723 USA
| | - Shannon Sweeney
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723 USA
| | - Jessie Yangxiang Guo
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903 USA.,Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08854 USA
| | - Alessia Lodi
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723 USA
| | - Stefano Tiziani
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723 USA
| | - Eileen White
- Rutgers Cancer Institute of New Jersey, 195 Little Albany Street, New Brunswick, NJ 08903 USA.,Department of Chemical Biology, Rutgers Ernest Mario School of Pharmacy, Piscataway, NJ 08854 USA
| | - Stephen D Hursting
- Department of Nutritional Sciences, University of Texas at Austin, Austin, TX 78723 USA.,Department of Nutrition, University of North Carolina, Chapel Hill, NC 27517 USA.,Department of Nutrition, University of North Carolina at Chapel Hill, 2115 Michael Hooker Research Center, Campus Box 7461, Chapel Hill, NC 27599 USA
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691
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Naoxintong/PPARα Signaling Inhibits H9c2 Cell Apoptosis and Autophagy in Response to Oxidative Stress. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:4370381. [PMID: 27668004 PMCID: PMC5030446 DOI: 10.1155/2016/4370381] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/21/2016] [Indexed: 12/24/2022]
Abstract
Naoxintong (NXT) is an empirical formula based on the principle of traditional Chinese medicine, which has been approved by China Food and Drug Administration (CFDA) and is widely used for treatment of patients with cerebrovascular and cardiovascular diseases in China. The aim of this study is to investigate the protective mechanism of NXT on H9c2 cells (cardiogenic cell line) in response to H2O2. MTT, Western blot, and flow cytometry (FCM) methods were used to identify the protective effect of NXT extract on H2O2-induced H9c2 cells. Here we found that NXT extract significantly increased H9c2 cell viability and reduced H2O2-induced cell apoptosis and autophagy. More importantly, NXT inhibited H2O2-induced H9c2 cell apoptosis and autophagy by increasing PPARα protein levels. In contrast, silenced PPARα terminated NXT protective effect on H2O2-induced H9c2 cells. These findings suggest that NXT/PPARα signaling suppressed H2O2-induced H9c2 cell apoptosis and autophagy.
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692
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Boya P, Esteban-Martínez L, Serrano-Puebla A, Gómez-Sintes R, Villarejo-Zori B. Autophagy in the eye: Development, degeneration, and aging. Prog Retin Eye Res 2016; 55:206-245. [PMID: 27566190 DOI: 10.1016/j.preteyeres.2016.08.001] [Citation(s) in RCA: 162] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 08/15/2016] [Accepted: 08/18/2016] [Indexed: 02/06/2023]
Abstract
Autophagy is a catabolic pathway that promotes the degradation and recycling of cellular components. Proteins, lipids, and even whole organelles are engulfed in autophagosomes and delivered to the lysosome for elimination. In response to stress, autophagy mediates the degradation of cell components, which are recycled to generate the nutrients and building blocks required to sustain cellular homeostasis. Moreover, it plays an important role in cellular quality control, particularly in neurons, in which the total burden of altered proteins and damaged organelles cannot be reduced by redistribution to daughter cells through cell division. Research has only begun to examine the role of autophagy in the visual system. The retina, a light-sensitive tissue, detects and transmits electrical impulses through the optic nerve to the visual cortex in the brain. Both the retina and the eye are exposed to a variety of environmental insults and stressors, including genetic mutations and age-associated alterations that impair their function. Here, we review the main studies that have sought to explain autophagy's importance in visual function. We describe the role of autophagy in retinal development and cell differentiation, and discuss the implications of autophagy dysregulation both in physiological aging and in important diseases such as age-associated macular degeneration and glaucoma. We also address the putative role of autophagy in promoting photoreceptor survival and discuss how selective autophagy could provide alternative means of protecting retinal cells. The findings reviewed here underscore the important role of autophagy in maintaining proper retinal function and highlight novel therapeutic approaches for blindness and other diseases of the eye.
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Affiliation(s)
- Patricia Boya
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain.
| | - Lorena Esteban-Martínez
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Ana Serrano-Puebla
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Raquel Gómez-Sintes
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Beatriz Villarejo-Zori
- Autophagy Lab, Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
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693
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Han CY, Kim TH, Koo JH, Kim SG. Farnesoid X receptor as a regulator of fuel consumption and mitochondrial function. Arch Pharm Res 2016; 39:1062-74. [PMID: 27515052 DOI: 10.1007/s12272-016-0812-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Accepted: 08/04/2016] [Indexed: 12/24/2022]
Abstract
Maintenance of energy homeostasis is crucial for survival of organism. There exists a close link between energy metabolism and cell survival, which are coordinately regulated by common signaling pathways. Farnesoid X receptor (FXR) serves as a ligand-mediated transcription factor to regulate diverse genes involved in bile acid, lipid, and glucose metabolism, controlling cellular and systemic energy metabolism. Another important aspect on FXR biology is related to its beneficial effect on cell survival. FXR exerts antioxidative and cytoprotective effect, which is closely associated with the ability of FXR to regulate mitochondrial function. To maintain complex biological processes under homeostasis, FXR activity needs to be dynamically and tightly controlled by different signaling pathways and modifications. In this review, we discuss the role of FXR in the regulation of energy metabolism and cell survival, with the goal of understanding molecular basis for FXR regulation in physiological and pathological conditions. This information may be of assistance in understanding recent advancements of FXR research and strategies for the prevention and treatment of metabolic disorders.
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Affiliation(s)
- Chang Yeob Han
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Tae Hyun Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Ja Hyun Koo
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea
| | - Sang Geon Kim
- College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Korea.
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694
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Adaptive Benefits of Storage Strategy and Dual AMPK/TOR Signaling in Metabolic Stress Response. PLoS One 2016; 11:e0160247. [PMID: 27505075 PMCID: PMC4978418 DOI: 10.1371/journal.pone.0160247] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Accepted: 07/15/2016] [Indexed: 11/19/2022] Open
Abstract
Cellular metabolism must ensure that supply of nutrient meets the biosynthetic and bioenergetic needs. Cells have therefore developed sophisticated signaling and regulatory pathways in order to cope with dynamic fluctuations of both resource and demand and to regulate accordingly diverse anabolic and catabolic processes. Intriguingly, these pathways are organized around a relatively small number of regulatory hubs, such as the highly conserved AMPK and TOR kinase families in eukaryotic cells. Here, the global metabolic adaptations upon dynamic environment are investigated using a prototypical model of regulated metabolism. In this model, the optimal enzyme profiles as well as the underlying regulatory architecture are identified by combining perturbation and evolutionary methods. The results reveal the existence of distinct classes of adaptive strategies, which differ in the management of storage reserve depending on the intensity of the stress and in the regulation of ATP-producing reaction depending on the nature of the stress. The regulatory architecture that optimally implements these adaptive features is characterized by a crosstalk between two specialized signaling pathways, which bears close similarities with the sensing and regulatory properties of AMPK and TOR pathways.
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695
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Molecular targets of gambogic acid in cancer: recent trends and advancements. Tumour Biol 2016; 37:12915-12925. [DOI: 10.1007/s13277-016-5194-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 07/13/2016] [Indexed: 12/11/2022] Open
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696
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Samarasinghe KTG, Munkanatta Godage DNP, Zhou Y, Ndombera FT, Weerapana E, Ahn YH. A clickable glutathione approach for identification of protein glutathionylation in response to glucose metabolism. MOLECULAR BIOSYSTEMS 2016; 12:2471-80. [PMID: 27216279 PMCID: PMC4955733 DOI: 10.1039/c6mb00175k] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Glucose metabolism and mitochondrial function are closely interconnected with cellular redox-homeostasis. Although glucose starvation, which mimics ischemic conditions or insufficient vascularization, is known to perturb redox-homeostasis, global and individual protein glutathionylation in response to glucose metabolism or mitochondrial activity remains largely unknown. In this report, we use our clickable glutathione approach, which forms clickable glutathione (azido-glutathione) by using a mutant of glutathione synthetase (GS M4), for detection and identification of protein glutathionylation in response to glucose starvation. We found that protein glutathionylation is readily induced in HEK293 cells in response to low glucose concentrations when mitochondrial reactive oxygen species (ROS) are elevated in cells, and glucose is the major determinant for inducing reversible glutathionylation. Proteomic and biochemical analysis identified over 1300 proteins, including SMYD2, PP2Cα, and catalase. We further showed that PP2Cα is glutathionylated at C314 in a C-terminal domain, and PP2Cα C314 glutathionylation disrupts the interaction with mGluR3, an important glutamate receptor associated with synaptic plasticity.
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Affiliation(s)
| | | | - Yani Zhou
- Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467, USA
| | - Fidelis T Ndombera
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
| | - Eranthie Weerapana
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
| | - Young-Hoon Ahn
- Department of Chemistry, Wayne State University, Detroit, Michigan 48202, USA.
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697
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Polishchuk EV, Polishchuk RS. The emerging role of lysosomes in copper homeostasis. Metallomics 2016; 8:853-62. [PMID: 27339113 DOI: 10.1039/c6mt00058d] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The lysosomal system operates as a focal point where a number of important physiological processes such as endocytosis, autophagy and nutrient sensing converge. One of the key functions of lysosomes consists of regulating the metabolism/homeostasis of metals. Metal-containing components are carried to the lysosome through incoming membrane flows, while numerous transporters allow metal ions to move across the lysosome membrane. These properties enable lysosomes to direct metal fluxes to the sites where metal ions are either used by cellular components or sequestered. Copper belongs to a group of metals that are essential for the activity of vitally important enzymes, although it is toxic when in excess. Thus, copper uptake, supply and intracellular compartmentalization have to be tightly regulated. An increasing number of publications have indicated that these processes involve lysosomes. Here we review studies that reveal the expanding role of the lysosomal system as a hub for the control of Cu homeostasis and for the regulation of key Cu-dependent processes in health and disease.
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Affiliation(s)
- Elena V Polishchuk
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, Pozzuoli (NA), 80078, Italy.
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698
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Galluzzi L, Bravo-San Pedro JM, Blomgren K, Kroemer G. Autophagy in acute brain injury. Nat Rev Neurosci 2016; 17:467-84. [PMID: 27256553 DOI: 10.1038/nrn.2016.51] [Citation(s) in RCA: 154] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Autophagy is an evolutionarily ancient mechanism that ensures the lysosomal degradation of old, supernumerary or ectopic cytoplasmic entities. Most eukaryotic cells, including neurons, rely on proficient autophagic responses for the maintenance of homeostasis in response to stress. Accordingly, autophagy mediates neuroprotective effects following some forms of acute brain damage, including methamphetamine intoxication, spinal cord injury and subarachnoid haemorrhage. In some other circumstances, however, the autophagic machinery precipitates a peculiar form of cell death (known as autosis) that contributes to the aetiology of other types of acute brain damage, such as neonatal asphyxia. Here, we dissect the context-specific impact of autophagy on non-infectious acute brain injury, emphasizing the possible therapeutic application of pharmacological activators and inhibitors of this catabolic process for neuroprotection.
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Affiliation(s)
- Lorenzo Galluzzi
- Equipe 11 Labellisée Ligue Contre le Cancer, Centre de Recherche des Cordeliers, 75006 Paris, France.,INSERM, U1138, 75006 Paris, France.,Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006 Paris, France.,Université Pierre et Marie Curie/Paris VI, 75006 Paris, France.,Gustave Roussy Comprehensive Cancer Institute, 94805 Villejuif, France
| | - José Manuel Bravo-San Pedro
- Equipe 11 Labellisée Ligue Contre le Cancer, Centre de Recherche des Cordeliers, 75006 Paris, France.,INSERM, U1138, 75006 Paris, France.,Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006 Paris, France.,Université Pierre et Marie Curie/Paris VI, 75006 Paris, France.,Gustave Roussy Comprehensive Cancer Institute, 94805 Villejuif, France
| | - Klas Blomgren
- Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital Q2:07, 17176 Stockholm, Sweden
| | - Guido Kroemer
- Equipe 11 Labellisée Ligue Contre le Cancer, Centre de Recherche des Cordeliers, 75006 Paris, France.,INSERM, U1138, 75006 Paris, France.,Université Paris Descartes/Paris V, Sorbonne Paris Cité, 75006 Paris, France.,Université Pierre et Marie Curie/Paris VI, 75006 Paris, France.,Karolinska Institute, Department of Women's and Children's Health, Karolinska University Hospital Q2:07, 17176 Stockholm, Sweden.,Metabolomics and Cell Biology Platforms, Gustave Roussy Comprehensive Cancer Institute, 94805 Villejuif, France.,Pôle de Biologie, Hopitâl Européen George Pompidou, AP-HP, 75015 Paris, France
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699
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Kruppa AJ, Kendrick-Jones J, Buss F. Myosins, Actin and Autophagy. Traffic 2016; 17:878-90. [PMID: 27146966 PMCID: PMC4957615 DOI: 10.1111/tra.12410] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 05/02/2016] [Accepted: 05/02/2016] [Indexed: 12/20/2022]
Abstract
Myosin motor proteins working together with the actin cytoskeleton drive a wide range of cellular processes. In this review, we focus on their roles in autophagy – the pathway the cell uses to ensure homeostasis by targeting pathogens, misfolded proteins and damaged organelles for degradation. The actin cytoskeleton regulated by a host of nucleating, anchoring and stabilizing proteins provides the filament network for the delivery of essential membrane vesicles from different cellular compartments to the autophagosome. Actin networks have also been implicated in structurally supporting the expanding phagophore, moving autophagosomes and enabling efficient fusion with the lysosome. Only a few myosins have so far been shown to play a role in autophagy. Non‐muscle myosin IIA functions in the early stages delivering membrane for the initial formation of the autophagosome, whereas myosin IC and myosin VI are involved in the final stages providing specific membranes for autophagosome maturation and its fusion with the lysosome.
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Affiliation(s)
- Antonina J Kruppa
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
| | - John Kendrick-Jones
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, UK
| | - Folma Buss
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge Biomedical Campus, Wellcome Trust/MRC Building, Hills Road, Cambridge, CB2 0XY, UK
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700
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Pabon MA, Ma KC, Choi AMK. Autophagy and Obesity-Related Lung Disease. Am J Respir Cell Mol Biol 2016; 54:636-46. [PMID: 26900794 PMCID: PMC5455357 DOI: 10.1165/rcmb.2016-0045ps] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 02/22/2016] [Indexed: 12/11/2022] Open
Abstract
Obesity-related disease is a significant source of premature death and economic burden globally. It is also a common comorbidity in patients suffering from lung disease, affecting both severity and treatment success. However, this complex association between obesity and the lung is poorly understood. Autophagy is a self-recycling homeostatic process that has been linked to beneficial or deleterious effects, depending on the specific lung disease. Obesity affects autophagy in a tissue-specific manner, activating autophagy in adipocytes and impairing autophagy in hepatocytes, immune cells, and pancreatic β-cells, among others. Obesity is also characterized by chronic low-grade inflammation that can be modulated by the pro- and antiinflammatory effects of the autophagic machinery. Scant evidence exists regarding the impact of autophagy in obesity-related lung diseases, but there are communal pathways that could be related to disease pathogenesis. Important signaling molecules in obesity, including IL-17, leptin, adiponectin, NLRP3 inflammasome, and TLR-4, have been implicated in the pathogenesis of lung disease. These mediators are known to be modulated by autophagy activity. In this perspective, we highlight the recent advances in the understanding of autophagy in obesity-related conditions, as well as the potential mechanisms that can link autophagy and obesity in the pathogenesis of lung disease.
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Affiliation(s)
- Maria A Pabon
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Kevin C Ma
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, New York
| | - Augustine M K Choi
- Division of Pulmonary and Critical Care Medicine, Joan and Sanford I. Weill Department of Medicine, Weill Cornell Medicine, New York, New York
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