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Hippman RS, Snead AM, Petros ZA, Korkmaz-Vaisys MA, Patel S, Sotelo D, Dobria A, Salkovski M, Nguyen TTA, Linares R, Cologna SM, Gowrishankar S, Aldrich LN. Discovery of a Small-Molecule Modulator of the Autophagy-Lysosome Pathway That Targets Lamin A/C and LAMP1, Induces Autophagic Flux, and Affects Lysosome Positioning in Neurons. ACS Chem Neurosci 2023; 14:4363-4382. [PMID: 38069806 PMCID: PMC10739612 DOI: 10.1021/acschemneuro.3c00573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/22/2023] [Accepted: 11/27/2023] [Indexed: 12/21/2023] Open
Abstract
Autophagy is a major catabolic degradation and recycling process that maintains homeostasis in cells and is especially important in postmitotic neurons. We implemented a high-content phenotypic assay to discover small molecules that promote autophagic flux and completed target identification and validation studies to identify protein targets that modulate the autophagy pathway and promote neuronal health and survival. Efficient syntheses of the prioritized compounds were developed to readily access analogues of the initial hits, enabling initial structure-activity relationship studies to improve potency and preparation of a biotin-tagged pulldown probe that retains activity. This probe facilitated target identification and validation studies through pulldown and competition experiments using both an unbiased proteomics approach and western blotting to reveal Lamin A/C and LAMP1 as the protein targets of compound RH1115. Evaluation of RH1115 in neurons revealed that this compound induces changes to LAMP1 vesicle properties and alters lysosome positioning. Dysfunction of the autophagy-lysosome pathway has been implicated in a variety of neurodegenerative diseases, including Alzheimer's disease, highlighting the value of new strategies for therapeutic modulation and the importance of small-molecule probes to facilitate the study of autophagy regulation in cultured neurons and in vivo.
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Affiliation(s)
- Ryan S. Hippman
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Amanda M. Snead
- Department
of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, 808 S. Wood Street, Chicago, Illinois 60612, United States
| | - Zoe A. Petros
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Melissa A. Korkmaz-Vaisys
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Sruchi Patel
- Department
of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, 808 S. Wood Street, Chicago, Illinois 60612, United States
| | - Daniel Sotelo
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Andrew Dobria
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Maryna Salkovski
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Thu T. A. Nguyen
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Ricardo Linares
- Department
of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, 808 S. Wood Street, Chicago, Illinois 60612, United States
| | - Stephanie M. Cologna
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
| | - Swetha Gowrishankar
- Department
of Anatomy and Cell Biology, College of Medicine, University of Illinois Chicago, 808 S. Wood Street, Chicago, Illinois 60612, United States
| | - Leslie N. Aldrich
- Department
of Chemistry, College of Liberal Arts and Sciences, University of Illinois Chicago, 845 W. Taylor Street, Chicago, Illinois 60607, United States
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2
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Rahman MA, Rahman MS, Parvez MAK, Kim B. The Emerging Role of Autophagy as a Target of Environmental Pollutants: An Update on Mechanisms. TOXICS 2023; 11:toxics11020135. [PMID: 36851010 PMCID: PMC9965655 DOI: 10.3390/toxics11020135] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 01/09/2023] [Accepted: 01/28/2023] [Indexed: 06/09/2023]
Abstract
Autophagy is an evolutionarily conserved cellular system crucial for cellular homeostasis that protects cells from a broad range of internal and extracellular stresses. Autophagy decreases metabolic load and toxicity by removing damaged cellular components. Environmental contaminants, particularly industrial substances, can influence autophagic flux by enhancing it as a protective response, preventing it, or converting its protective function into a pro-cell death mechanism. Environmental toxic materials are also notorious for their tendency to bioaccumulate and induce pathophysiological vulnerability. Many environmental pollutants have been found to influence stress which increases autophagy. Increasing autophagy was recently shown to improve stress resistance and reduce genetic damage. Moreover, suppressing autophagy or depleting its resources either increases or decreases toxicity, depending on the circumstances. The essential process of selective autophagy is utilized by mammalian cells in order to eliminate particulate matter, nanoparticles, toxic metals, and smoke exposure without inflicting damage on cytosolic components. Moreover, cigarette smoke and aging are the chief causes of chronic obstructive pulmonary disease (COPD)-emphysema; however, the disease's molecular mechanism is poorly known. Therefore, understanding the impacts of environmental exposure via autophagy offers new approaches for risk assessment, protection, and preventative actions which will counter the harmful effects of environmental contaminants on human and animal health.
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Affiliation(s)
- Md. Ataur Rahman
- Department of Pathology, College of Korean Medicine, Kyung Hee University, 1-5 Hoegidong Dongdaemun-gu, Seoul 02447, Republic of Korea
- Korean Medicine-Based Drug Repositioning Cancer Research Center, College of Korean Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Md Saidur Rahman
- Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, Anseong 17546, Republic of Korea
| | | | - Bonglee Kim
- Department of Pathology, College of Korean Medicine, Kyung Hee University, 1-5 Hoegidong Dongdaemun-gu, Seoul 02447, Republic of Korea
- Korean Medicine-Based Drug Repositioning Cancer Research Center, College of Korean Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
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Vega-Rubín-de-Celis S, Kinch L, Peña-Llopis S. Regulation of Beclin 1-Mediated Autophagy by Oncogenic Tyrosine Kinases. Int J Mol Sci 2020; 21:ijms21239210. [PMID: 33287140 PMCID: PMC7729755 DOI: 10.3390/ijms21239210] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/28/2020] [Accepted: 12/01/2020] [Indexed: 12/12/2022] Open
Abstract
Beclin 1 is a major regulator of autophagy, and it is a core component of the class III PI3K complexes. Beclin 1 is a highly conserved protein and its function is regulated in a number of ways, including post-translational modifications. Several studies indicate that receptor and non-receptor tyrosine kinases regulate autophagy activity in cancer, and some suggest the importance of Beclin 1 tyrosine phosphorylation in this process. Here we summarize the current knowledge of the mechanism whereby some oncogenic tyrosine kinases regulate autophagy through Beclin 1.
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Affiliation(s)
- Silvia Vega-Rubín-de-Celis
- Institute for Cell Biology (Cancer Research), University Hospital Essen, 45147 Essen, Germany
- Correspondence: or
| | - Lisa Kinch
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
| | - Samuel Peña-Llopis
- Translational Genomics in Solid Tumors, German Cancer Consortium (DKTK) and German Cancer Research Center, University Hospital Essen, 45147 Essen, Germany;
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4
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Xin X, Du X, Xiao Q, Azevedo HS, He W, Yin L. Drug Nanorod-Mediated Intracellular Delivery of microRNA-101 for Self-sensitization via Autophagy Inhibition. NANO-MICRO LETTERS 2019; 11:82. [PMID: 34138035 PMCID: PMC7770860 DOI: 10.1007/s40820-019-0310-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 08/30/2019] [Indexed: 05/20/2023]
Abstract
Autophagy is closely related to the drug resistance and metastasis in cancer therapy. Nanoparticle-mediated co-delivery of combinatorial therapy with small-molecular drugs and nucleic acids is promising to address drug resistance. Here, a drug-delivering-drug (DDD) platform consisting of anti-tumor-drug nanorods as a vehicle for cytosol delivery of nucleic acid (miR-101) with potent autophagic-inhibition activity is reported for combinatorial therapy. The developed 180-nm nanoplatform, with total drug loading of up to 66%, delivers miR-101 to cancer cells, with threefold increase in intracellular level compared to conventional gene carriers and inhibits the autophagy significantly, along with above twofold reduction in LC3II mRNA and approximately fivefold increase in p62 mRNA over the control demonstrated in the results in vivo. And in turn, the delivery of miR-101 potentiates the drug's ability to kill cancer cells, with a threefold increase in apoptosis over that of chemotherapy alone. The anti-tumor study in vivo indicates the combined therapy that enables a reduction of 80% in tumor volume and > twofold increase in apoptosis than of the single-drug strategy. In summary, via the carrier-free strategy of DDD, this work provides a delivery platform that can be easily customized to overcome drug resistance and facilitates the delivery of combined therapy of small-molecular drugs and nucleic acids.
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Affiliation(s)
- Xiaofei Xin
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Xiaoqing Du
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Qingqing Xiao
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, People's Republic of China
| | - Helena S Azevedo
- School of Engineering and Materials Science, Institute of Bioengineering, Queen Mary, University of London, London, E1 4NS, UK
| | - Wei He
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, People's Republic of China.
| | - Lifang Yin
- Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, People's Republic of China.
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5
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Luo H, Han L, Xu J. Apelin/APJ system: A novel promising target for neurodegenerative diseases. J Cell Physiol 2019; 235:638-657. [DOI: 10.1002/jcp.29001] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 06/06/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Huaiqing Luo
- Department of Physiology Changsha Medical University Changsha Hunan China
- Department of Physiology, School of Basic Medical Science Central South University Changsha Hunan China
| | - Li Han
- Department of Physiology Changsha Medical University Changsha Hunan China
| | - Jin Xu
- School of Pharmaceutical Sciences Changsha Medical University Changsha Hunan China
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6
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Abstract
Most common neurodegenerative diseases feature deposition of protein amyloids and degeneration of brain networks. Amyloids are ordered protein assemblies that can act as templates for their own replication through monomer addition. Evidence suggests that this characteristic may underlie the progression of pathology in neurodegenerative diseases. Many different amyloid proteins, including Aβ, tau, and α-synuclein, exhibit properties similar to those of infectious prion protein in experimental systems: discrete and self-replicating amyloid structures, transcellular propagation of aggregation, and transmissible neuropathology. This review discusses the contribution of prion phenomena and transcellular propagation to the progression of pathology in common neurodegenerative diseases such as Alzheimer's and Parkinson's. It reviews fundamental events such as cell entry, amplification, and transcellular movement. It also discusses amyloid strains, which produce distinct patterns of neuropathology and spread through the nervous system. These concepts may impact the development of new diagnostic and therapeutic strategies.
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Affiliation(s)
- Jaime Vaquer-Alicea
- Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
| | - Marc I Diamond
- Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA;
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7
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Panda PK, Fahrner A, Vats S, Seranova E, Sharma V, Chipara M, Desai P, Torresi J, Rosenstock T, Kumar D, Sarkar S. Chemical Screening Approaches Enabling Drug Discovery of Autophagy Modulators for Biomedical Applications in Human Diseases. Front Cell Dev Biol 2019; 7:38. [PMID: 30949479 PMCID: PMC6436197 DOI: 10.3389/fcell.2019.00038] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 03/01/2019] [Indexed: 12/12/2022] Open
Abstract
Autophagy is an intracellular degradation pathway for malfunctioning aggregation-prone proteins, damaged organelles, unwanted macromolecules and invading pathogens. This process is essential for maintaining cellular and tissue homeostasis that contribute to organismal survival. Autophagy dysfunction has been implicated in the pathogenesis of diverse human diseases, and therefore, therapeutic exploitation of autophagy is of potential biomedical relevance. A number of chemical screening approaches have been established for the drug discovery of autophagy modulators based on the perturbations of autophagy reporters or the clearance of autophagy substrates. These readouts can be detected by fluorescence and high-content microscopy, flow cytometry, microplate reader and immunoblotting, and the assays have evolved to enable high-throughput screening and measurement of autophagic flux. Several pharmacological modulators of autophagy have been identified that act either via the classical mechanistic target of rapamycin (mTOR) pathway or independently of mTOR. Many of these autophagy modulators have been demonstrated to exert beneficial effects in transgenic models of neurodegenerative disorders, cancer, infectious diseases, liver diseases, myopathies as well as in lifespan extension. This review describes the commonly used chemical screening approaches in mammalian cells and the key autophagy modulators identified through these methods, and highlights the therapeutic benefits of these compounds in specific disease contexts.
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Affiliation(s)
- Prashanta Kumar Panda
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Alexandra Fahrner
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Somya Vats
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Elena Seranova
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Vartika Sharma
- Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Miruna Chipara
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Priyal Desai
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Jorge Torresi
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil
| | - Tatiana Rosenstock
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil
| | - Dhiraj Kumar
- Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | - Sovan Sarkar
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom
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8
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Seranova E, Ward C, Chipara M, Rosenstock TR, Sarkar S. In Vitro Screening Platforms for Identifying Autophagy Modulators in Mammalian Cells. Methods Mol Biol 2019; 1880:389-428. [PMID: 30610712 DOI: 10.1007/978-1-4939-8873-0_26] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Autophagy is a vital homeostatic pathway essential for cellular survival and human health. It primarily functions as an intracellular degradation process for the turnover of aggregation-prone proteins and unwanted organelles. Dysregulation of autophagy underlying diverse human diseases reduces cell viability, whereas stimulation of autophagy is cytoprotective in a number of transgenic disease models including neurodegenerative disorders. Thus, therapeutic exploitation of autophagy is considered a potential treatment strategy in certain human diseases, and therefore, chemical inducers of autophagy have tremendous biomedical relevance. In this review, we describe the in vitro screening platforms to identify autophagy modulators in mammalian cells using various methodologies including fluorescence and high-content imaging, flow cytometry, fluorescence and luminescence detection by microplate reader, immunoblotting, and immunofluorescence. The commonly used autophagy reporters in these screening platforms are either based on autophagy marker like LC3 or autophagy substrate such as aggregation-prone proteins or p62/SQSTM1. The reporters and assays for monitoring autophagy are evolving over time to become more sensitive in measuring autophagic flux with the capability of high-throughput applications for drug discovery. Here we highlight these developments and also describe the stringent secondary autophagy assays for characterizing the autophagy modulators arising from the primary screen. Since autophagy is implicated in myriad human physiological and pathological conditions, these technologies will enable identifying novel chemical modulators or genetic regulators of autophagy that will be of biomedical and fundamental importance to human health.
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Affiliation(s)
- Elena Seranova
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Carl Ward
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Miruna Chipara
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Tatiana R Rosenstock
- Department of Physiological Science, Santa Casa de São Paulo School of Medical Science, São Paulo, Brazil
| | - Sovan Sarkar
- Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.
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9
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Mishra P, Ammanathan V, Manjithaya R. Chemical Biology Strategies to Study Autophagy. Front Cell Dev Biol 2018; 6:160. [PMID: 30538986 PMCID: PMC6277461 DOI: 10.3389/fcell.2018.00160] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 11/06/2018] [Indexed: 11/13/2022] Open
Abstract
Growing amount of evidence in the last two decades highlight that macroautophagy (generally referred to as autophagy) is not only indispensable for survival in yeast but also equally important to maintain cellular quality control in higher eukaryotes as well. Importantly, dysfunctional autophagy has been explicitly shown to be involved in various physiological and pathological conditions such as cell death, cancer, neurodegenerative, and other diseases. Therefore, modulation and regulation of the autophagy pathway has emerged as an alternative strategy for the treatment of various disease conditions in the recent years. Several studies have shown genetic or pharmacological modulation of autophagy to be effective in treating cancer, clearing intracellular aggregates and pathogens. Understanding and controlling the autophagic flux, either through a genetic or pharmacological approach is therefore a highly promising approach and of great scientific interest as spatiotemporal and cell-tissue-organ level autophagy regulation is not clearly understood. Indeed, chemical biology approaches that identify small molecule effectors of autophagy have thus a dual benefit: the modulators act as tools to study and understand the process of autophagy, and may also have therapeutic potential. In this review, we discuss different strategies that have appeared to screen and identify potent small molecule modulators of autophagy.
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Affiliation(s)
- Piyush Mishra
- Autophagy Lab, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Veena Ammanathan
- Autophagy Lab, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | - Ravi Manjithaya
- Autophagy Lab, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
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10
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Dysregulation of autophagy as a common mechanism in lysosomal storage diseases. Essays Biochem 2017; 61:733-749. [PMID: 29233882 PMCID: PMC5869865 DOI: 10.1042/ebc20170055] [Citation(s) in RCA: 128] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 10/08/2017] [Accepted: 10/12/2017] [Indexed: 12/19/2022]
Abstract
The lysosome plays a pivotal role between catabolic and anabolic processes as the nexus for signalling pathways responsive to a variety of factors, such as growth, nutrient availability, energetic status and cellular stressors. Lysosomes are also the terminal degradative organelles for autophagy through which macromolecules and damaged cellular components and organelles are degraded. Autophagy acts as a cellular homeostatic pathway that is essential for organismal physiology. Decline in autophagy during ageing or in many diseases, including late-onset forms of neurodegeneration is considered a major contributing factor to the pathology. Multiple lines of evidence indicate that impairment in autophagy is also a central mechanism underlying several lysosomal storage disorders (LSDs). LSDs are a class of rare, inherited disorders whose histopathological hallmark is the accumulation of undegraded materials in the lysosomes due to abnormal lysosomal function. Inefficient degradative capability of the lysosomes has negative impact on the flux through the autophagic pathway, and therefore dysregulated autophagy in LSDs is emerging as a relevant disease mechanism. Pathology in the LSDs is generally early-onset, severe and life-limiting but current therapies are limited or absent; recognizing common autophagy defects in the LSDs raises new possibilities for therapy. In this review, we describe the mechanisms by which LSDs occur, focusing on perturbations in the autophagy pathway and present the latest data supporting the development of novel therapeutic approaches related to the modulation of autophagy.
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11
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Autophagy regulation in preeclampsia: Pros and cons. J Reprod Immunol 2017; 123:17-23. [DOI: 10.1016/j.jri.2017.08.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Accepted: 08/16/2017] [Indexed: 12/11/2022]
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12
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Loos B, Klionsky DJ, Wong E. Augmenting brain metabolism to increase macro- and chaperone-mediated autophagy for decreasing neuronal proteotoxicity and aging. Prog Neurobiol 2017; 156:90-106. [DOI: 10.1016/j.pneurobio.2017.05.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 05/06/2017] [Accepted: 05/08/2017] [Indexed: 12/14/2022]
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13
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Mishra P, Dauphinee AN, Ward C, Sarkar S, Gunawardena AHLAN, Manjithaya R. Discovery of pan autophagy inhibitors through a high-throughput screen highlights macroautophagy as an evolutionarily conserved process across 3 eukaryotic kingdoms. Autophagy 2017; 13:1556-1572. [PMID: 28792845 PMCID: PMC5612355 DOI: 10.1080/15548627.2017.1339002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Due to the involvement of macroautophagy/autophagy in different pathophysiological conditions such as infections, neurodegeneration and cancer, identification of novel small molecules that modulate the process is of current research and clinical interest. In this work, we developed a luciferase-based sensitive and robust kinetic high-throughput screen (HTS) of small molecules that modulate autophagic degradation of peroxisomes in the budding yeast Saccharomyces cerevisiae. Being a pathway-specific rather than a target-driven assay, we identified small molecule modulators that acted at key steps of autophagic flux. Two of the inhibitors, Bay11 and ZPCK, obtained from the screen were further characterized using secondary assays in yeast. Bay11 inhibited autophagy at a step before fusion with the vacuole whereas ZPCK inhibited the cargo degradation inside the vacuole. Furthermore, we demonstrated that these molecules altered the process of autophagy in mammalian cells as well. Strikingly, these molecules also modulated autophagic flux in a novel model plant, Aponogeton madagascariensis. Thus, using small molecule modulators identified by using a newly developed HTS autophagy assay, our results support that macroautophagy is a conserved process across fungal, animal and plant kingdoms.
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Affiliation(s)
- Piyush Mishra
- a Molecular Biology and Genetics Unit , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bangalore , India
| | - Adrian N Dauphinee
- b Biology Department, Life Sciences Centre , Dalhousie University , Halifax , NS , Canada
| | - Carl Ward
- c Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences , University of Birmingham , Edgbaston, Birmingham , UK
| | - Sovan Sarkar
- c Institute of Cancer and Genomic Sciences, Institute of Biomedical Research, College of Medical and Dental Sciences , University of Birmingham , Edgbaston, Birmingham , UK
| | | | - Ravi Manjithaya
- a Molecular Biology and Genetics Unit , Jawaharlal Nehru Centre for Advanced Scientific Research , Jakkur, Bangalore , India
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14
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Mishra P, Rai S, Manjithaya R. A novel dual luciferase based high throughput assay to monitor autophagy in real time in yeast S. cerevisiae. Biochem Biophys Rep 2017; 11:138-146. [PMID: 28955778 PMCID: PMC5614714 DOI: 10.1016/j.bbrep.2017.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 06/09/2017] [Accepted: 07/20/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Macroautophagy is a cellular response to starvation wherein superfluous and damaged cytoplasmic constituents are degraded to provide energy for survival and to maintain cellular homeostasis. Dysfunctional autophagy is attributed to disease progression in several pathological conditions and therefore, autophagy has appeared as a potential pharmacological target for such conditions. OBJECTIVE In search of potential drugs that modulate autophagy, identifying small molecule effectors of autophagy is the primary step. The conventional autophagy assays have a limitation that they cannot be scaled down to a high throughput format, therefore, novel sensitive assays are needed to discover new candidate molecules. Keeping this rationale in mind, a dual luciferase based assay was developed in the yeast S. cerevisiae that could measure both selective and general autophagy in real time. METHODS Firefly and Renilla luciferase reporter genes were cloned under POT-1 promoter. Using fatty acid medium the promoter was induced and the luciferase cargo was allowed to build up. The cells were then transferred to starvation conditions to stimulate autophagy and the degradation of luciferase markers was followed with time. RESULTS AND CONCLUSION The assay was more sensitive than conventional assays and could be scaled down to a 384 well format using an automated system. A good Z-factor score indicated that the assay is highly suitable for High Throughput Screening (HTS) of small molecule libraries. Screening of a small molecule library with our assay identified several known and novel modulators of autophagy.
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Affiliation(s)
- Piyush Mishra
- Autophagy Lab, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Shashank Rai
- Autophagy Lab, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
| | - Ravi Manjithaya
- Autophagy Lab, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore, India
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15
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Harnett MM, Pineda MA, Latré de Laté P, Eason RJ, Besteiro S, Harnett W, Langsley G. From Christian de Duve to Yoshinori Ohsumi: More to autophagy than just dining at home. Biomed J 2017; 40:9-22. [PMID: 28411887 PMCID: PMC6138802 DOI: 10.1016/j.bj.2016.12.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 12/26/2016] [Accepted: 12/28/2016] [Indexed: 12/21/2022] Open
Abstract
Christian de Duve first coined the expression “autophagy” during his seminal work on the discovery of lysosomes, which led to him being awarded the Nobel Prize in Physiology or Medicine in 1974. The term was adopted to distinguish degradation of intracellular components from the uptake and degradation of extracellular substances that he called “heterophagy”. Studies until the 1990s were largely observational/morphological-based until in 1993 Yoshinori Oshumi described a genetic screen in yeast undergoing nitrogen deprivation that led to the isolation of autophagy-defective mutants now better known as ATG (AuTophaGy-related) genes. The screen identified mutants that fell into 15 complementation groups implying that at least 15 genes were involved in the regulation of autophagy in yeast undergoing nutrient deprivation, but today, 41 yeast ATG genes have been described and many (though not all) have orthologues in humans. Attempts to identify the genetic basis of autophagy led to an explosion in its research and it's not surprising that in 2016 Yoshinori Oshumi was awarded the Nobel Prize in Physiology or Medicine. Our aim here is not to exhaustively review the ever-expanding autophagy literature (>60 papers per week), but to celebrate Yoshinori Oshumi's Nobel Prize by highlighting just a few aspects that are not normally extensively covered. In an accompanying mini-review we address the role of autophagy in early-diverging eukaryote parasites that like yeast, lack lysosomes and so use a digestive vacuole to degrade autophagosome cargo and also discuss how parasitized host cells react to infection by subverting regulation of autophagy.
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Affiliation(s)
- Margaret M Harnett
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, UK.
| | - Miguel A Pineda
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, UK
| | - Perle Latré de Laté
- Inserm U1016, CNRS UMR8104, Cochin Institute, Paris, France; The laboratory of Comparative Cell Biology of Apicomplexa, Medical Faculty of Paris-Descartes University, Sorbonne Paris City, France
| | - Russell J Eason
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, Glasgow Biomedical Research Centre, University of Glasgow, Glasgow, UK
| | - Sébastien Besteiro
- DIMNP, UMR CNRS 5235, Montpellier University, Place Eugène Bataillon, Building 24, CC Montpellier, France
| | - William Harnett
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Gordon Langsley
- Inserm U1016, CNRS UMR8104, Cochin Institute, Paris, France; The laboratory of Comparative Cell Biology of Apicomplexa, Medical Faculty of Paris-Descartes University, Sorbonne Paris City, France.
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16
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Targeting autophagy as a strategy for drug discovery and therapeutic modulation. Future Med Chem 2017; 9:335-345. [DOI: 10.4155/fmc-2016-0210] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Autophagy is a self-protective mechanism of living cells or organisms under various stress conditions. Studies of human genetics and pathophysiology have implicated that alterations in autophagy affect the context of cellular homeostasis and disease-associated phenotypes. The molecular components of autophagy are currently being explored as new pharmacologic targets for drug development and therapeutic intervention of various diseases. Drugs that restore the normal autophagic pathways have the potential for effectively treating human disorders that depend on aberrations of autophagy. Here, we review the role of autophagy and its alterations in the pathogenesis of diverse diseases, and drug discovery strategies for modulating autophagy for therapeutic benefits as well as possible safety concerns and caveats associated with such approaches.
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17
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Hsieh CH, Lee LC, Leong WY, Yang TC, Yao CF, Fang K. A triazole derivative elicits autophagic clearance of polyglutamine aggregation in neuronal cells. DRUG DESIGN DEVELOPMENT AND THERAPY 2016; 10:2947-2957. [PMID: 27695292 PMCID: PMC5028077 DOI: 10.2147/dddt.s111903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Trinucleotide CAG repeat expansion in the coding region of genes has a propensity to form polyglutamine (polyQ) aggregates that contribute to neuronal disorders. Strategies in elevating autophagy to disintegrate the insoluble aggregates without injuring cells have become a major goal for therapy. In this work, a triazole derivative, OC-13, was found accelerating autophagic clearance of polyQ aggregation in human neuroblastoma cells following induction of the enhanced green fluorescence-conjugated chimeric protein that enclosed 79 polyQ repeats (Q79-EGFP). OC-13 accelerated autophagy development and removed nuclear Q79-EGFP aggregates. The increase of Beclin-1, turnover of LC3-I to LC3-II and degradation of p62 supported autophagy activation. Pretreatment of autophagy inhibitor, bafilomycin A1, not only suppressed autophagolysome fusion, but also impeded aggregate eradication. The study also showed that c-Jun N-terminal kinase/Beclin-1 pathway was activated during OC-13 treatment and c-Jun N-terminal kinase inhibitor impaired autophagy and final breakdown. Autophagic clearance of the insoluble aggregates demonstrated the feasibility of OC-13 in alleviating neuronal disorders because of expanded glutamine stretches.
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Affiliation(s)
| | | | | | | | - Ching-Fa Yao
- Department of Chemistry, National Taiwan Normal University, Taipei, Taiwan
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18
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Jo A, Jung J, Kim E, Park SB. A high-content screening platform with fluorescent chemical probes for the discovery of first-in-class therapeutics. Chem Commun (Camb) 2016; 52:7433-45. [PMID: 27166145 DOI: 10.1039/c6cc02587k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Phenotypic screening has emerged as a promising approach to discover novel first-in-class therapeutic agents. Rapid advances in phenotypic screening systems facilitate a high-throughput unbiased evaluation of compound libraries. However, limited sets of phenotypic changes are utilized in high-content screening, which require extensive genetic engineering. Therefore, it is critical to develop new chemical probes that can reflect phenotypic changes in any type of cells, especially primary cells, tissues, and organisms. Herein, we introduce our continuous efforts in the development of fluorescent bioprobes and their application to phenotypic screening. In addition, we emphasize the importance of the phenotype-based approach in conjunction with target identification at an early stage of research to accelerate the discovery of therapeutics with new modes of action.
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Affiliation(s)
- Ala Jo
- Department of Chemistry, Seoul National University, Seoul, 08826, Korea.
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19
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Liu L, Huang JS, Han C, Zhang GX, Xu XY, Shen Y, Li J, Jiang HY, Lin ZC, Xiong N, Wang T. Induced Pluripotent Stem Cells in Huntington's Disease: Disease Modeling and the Potential for Cell-Based Therapy. Mol Neurobiol 2015; 53:6698-6708. [PMID: 26659595 DOI: 10.1007/s12035-015-9601-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 12/01/2015] [Indexed: 12/31/2022]
Abstract
Huntington's disease (HD) is an incurable neurodegenerative disorder that is characterized by motor dysfunction, cognitive impairment, and behavioral abnormalities. It is an autosomal dominant disorder caused by a CAG repeat expansion in the huntingtin gene, resulting in progressive neuronal loss predominately in the striatum and cortex. Despite the discovery of the causative gene in 1993, the exact mechanisms underlying HD pathogenesis have yet to be elucidated. Treatments that slow or halt the disease process are currently unavailable. Recent advances in induced pluripotent stem cell (iPSC) technologies have transformed our ability to study disease in human neural cells. Here, we firstly review the progress made to model HD in vitro using patient-derived iPSCs, which reveal unique insights into illuminating molecular mechanisms and provide a novel human cell-based platform for drug discovery. We then highlight the promises and challenges for pluripotent stem cells that might be used as a therapeutic source for cell replacement therapy of the lost neurons in HD brains.
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Affiliation(s)
- Ling Liu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jin-Sha Huang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Chao Han
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Guo-Xin Zhang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xiao-Yun Xu
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Yan Shen
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Jie Li
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Hai-Yang Jiang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhi-Cheng Lin
- Department of Psychiatry, Harvard Medical School; Division of Alcohol and Drug Abuse, and Mailman Neuroscience Research Center, McLean Hospital, Belmont, MA, USA
| | - Nian Xiong
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Tao Wang
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
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20
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Role of autophagy in the pathogenesis of amyotrophic lateral sclerosis. Biochim Biophys Acta Mol Basis Dis 2015; 1852:2517-24. [DOI: 10.1016/j.bbadis.2015.08.005] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 12/12/2022]
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21
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Abstract
The autophagic system is involved in both bulk degradation of primarily long-lived cytoplasmic proteins as well as in selective degradation of cytoplasmic organelles. Autophagic flux is often defined as a measure of autophagic degradation activity, and a number of methods are currently utilized to assess autophagic flux. However, despite major advances in measuring various molecular aspects of the autophagic machinery, we remain less able to express autophagic flux in a highly sensitive, robust, and well-quantifiable manner. Here, we describe a conceptual framework for defining and measuring autophagosome flux at the single-cell level. The concept discussed here is based on the theoretical framework of metabolic control analysis, which distinguishes between the pathway along which there is a flow of material and the quantitative measure of this flow. By treating the autophagic system as a multistep pathway with each step characterized by a particular rate, we are able to provide a single-cell fluorescence live-cell imaging-based approach that describes the accurate assessment of the complete autophagosome pool size, the autophagosome flux, and the transition time required to turn over the intracellular autophagosome pool. In doing so, this perspective provides clarity on whether the system is at steady state or in a transient state moving towards a new steady state. It is hoped that this theoretical account of quantitatively measuring autophagosome flux may contribute towards a new direction in the field of autophagy, a standardized approach that allows the establishment of systematic flux databases of clinically relevant cell and tissue types that serve as important model systems for human pathologies.
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Affiliation(s)
- Ben Loos
- a Department of Physiological Sciences, Faculty of Science ; University of Stellenbosch ; Stellenbosch , South Africa
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22
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Abstract
Baseline physiological function of the mammalian heart is under the constant threat of environmental or intrinsic pathological insults. Cardiomyocyte proteins are thus subject to unremitting pressure to function optimally, and this depends on them assuming and maintaining proper conformation. This review explores the multiple defenses a cell may use for its proteins to assume and maintain correct protein folding and conformation. There are multiple quality control mechanisms to ensure that nascent polypeptides are properly folded and mature proteins maintain their functional conformation. When proteins do misfold, either in the face of normal or pathological stimuli or because of intrinsic mutations or post-translational modifications, they must either be refolded correctly or recycled. In the absence of these corrective processes, they may become toxic to the cell. Herein, we explore some of the underlying mechanisms that lead to proteotoxicity. The continued presence and chronic accumulation of misfolded or unfolded proteins can be disastrous in cardiomyocytes because these misfolded proteins can lead to aggregation or the formation of soluble peptides that are proteotoxic. This in turn leads to compromised protein quality control and precipitating a downward spiral of the cell's ability to maintain protein homeostasis. Some underlying mechanisms are discussed and the therapeutic potential of interfering with proteotoxicity in the heart is explored.
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Affiliation(s)
- Patrick M McLendon
- From the Department of Pediatrics, Children's Hospital Research Foundation, Cincinnati, OH
| | - Jeffrey Robbins
- From the Department of Pediatrics, Children's Hospital Research Foundation, Cincinnati, OH.
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23
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Interactions between Autophagy and Bacterial Toxins: Targets for Therapy? Toxins (Basel) 2015; 7:2918-58. [PMID: 26248079 PMCID: PMC4549733 DOI: 10.3390/toxins7082918] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 07/27/2015] [Accepted: 07/28/2015] [Indexed: 01/07/2023] Open
Abstract
Autophagy is a physiological process involved in defense mechanisms for clearing intracellular bacteria. The autophagic pathway is finely regulated and bacterial toxins interact with this process in a complex manner. Bacterial toxins also interact significantly with many biochemical processes. Evaluations of the effects of bacterial toxins, such as endotoxins, pore-forming toxins and adenylate cyclases, on autophagy could support the development of new strategies for counteracting bacterial pathogenicity. Treatment strategies could focus on drugs that enhance autophagic processes to improve the clearance of intracellular bacteria. However, further in vivo studies are required to decipher the upregulation of autophagy and potential side effects limiting such approaches. The capacity of autophagy activation strategies to improve the outcome of antibiotic treatment should be investigated in the future.
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24
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Induction of autophagy in rats upon overexpression of wild-type and mutant optineurin gene. BMC Cell Biol 2015; 16:14. [PMID: 25943884 PMCID: PMC4429416 DOI: 10.1186/s12860-015-0060-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 04/22/2015] [Indexed: 12/31/2022] Open
Abstract
Background Optineurin is a gene associated with normal tension glaucoma and amyotrophic lateral sclerosis. It has been reported previously that in cultured RGC5 cells, the turnover of endogenous optineurin involves mainly the ubiquitin-proteasome pathway (UPP). When optineurin is upregulated or mutated, the UPP function is compromised as evidenced by a decreased proteasome β5 subunit (PSMB5) level and autophagy is induced for clearance of the optineurin protein. Results Adeno-associated type 2 viral (AAV2) vectors for green fluorescence protein (GFP) only, GFP-tagged wild-type and Glu50Lys (E50K) mutated optineurin were intravitreally injected into rats for expression in retinal ganglion cells (RGCs). Following intravitreal injections, eyes that received optineurin vectors exhibited retinal thinning, as well as RGC and axonal loss compared to GFP controls. By immunostaining and Western blotting, the level of PSMB5 and autophagic substrate degradation marker p62 was reduced, and the level of autophagic marker microtubule associated protein 1 light chain 3 (LC3) was enhanced. The UPP impairment and autophagy induction evidently occurred in vivo as in vitro. The optineurin level, RGC and axonal counts, and apoptosis in AAV2-E50K-GFP-injected rat eyes were averted to closer to normal limits after treatment with rapamycin, an autophagic enhancer. Conclusions The UPP function was reduced and autophagy was induced when wild-type and E50K optineurin was overexpressed in rat eyes. This study validates the in vitro findings, confirming that UPP impairment and autophagy induction also occur in vivo. In addition, rapamycin is demonstrated to clear the accumulated mutant optineurin. This agent may potentially be useful for rescuing of the adverse optineurin phenotypes in vivo.
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25
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Abstract
Defects in autophagy have been linked to a wide range of medical illnesses, including cancer as well as infectious, neurodegenerative, inflammatory, and metabolic diseases. These observations have led to the hypothesis that autophagy inducers may prevent or treat certain clinical conditions. Lifestyle and nutritional factors, such as exercise and caloric restriction, may exert their known health benefits through the autophagy pathway. Several currently available FDA-approved drugs have been shown to enhance autophagy, and this autophagy-enhancing action may be repurposed for use in novel clinical indications. The development of new drugs that are designed to be more selective inducers of autophagy function in target organs is expected to maximize clinical benefits while minimizing toxicity. This Review summarizes the rationale and current approaches for developing autophagy inducers in medicine, the factors to be considered in defining disease targets for such therapy, and the potential benefits of such treatment for human health.
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26
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Dual Role of Autophagy in Neurodegenerative Diseases: The Case of Amyotrophic Lateral Sclerosis. CURRENT TOPICS IN NEUROTOXICITY 2015. [DOI: 10.1007/978-3-319-13939-5_4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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27
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Targeting autophagy in neurodegenerative diseases. Trends Pharmacol Sci 2014; 35:583-91. [DOI: 10.1016/j.tips.2014.09.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Revised: 08/28/2014] [Accepted: 09/03/2014] [Indexed: 12/14/2022]
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28
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Combating neurodegenerative disease with chemical probes and model systems. Nat Chem Biol 2014; 10:911-20. [PMID: 25325702 DOI: 10.1038/nchembio.1663] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/11/2014] [Indexed: 12/19/2022]
Abstract
The disheartening results of recent clinical trials for neurodegenerative disease (ND) therapeutics underscore the need for a more comprehensive understanding of the underlying disease biology before effective therapies can be devised. One hallmark of many NDs is a disruption in protein homeostasis. Therefore, investigating the role of protein homeostasis in these diseases is central to delineating their underlying pathobiology. Here, we review the seminal role that chemical biology has played in furthering the research on and treatment of dysfunctional protein homeostasis in NDs. We also discuss the vital and predictive role of model systems in identifying conserved homeostasis pathways and genes therein that are altered in neurodegeneration. Integrating approaches from chemical biology with the use of model systems yields a powerful toolkit with which to unravel the complexities of ND biology.
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29
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Martin DDO, Ladha S, Ehrnhoefer DE, Hayden MR. Autophagy in Huntington disease and huntingtin in autophagy. Trends Neurosci 2014; 38:26-35. [PMID: 25282404 DOI: 10.1016/j.tins.2014.09.003] [Citation(s) in RCA: 219] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Revised: 09/08/2014] [Accepted: 09/09/2014] [Indexed: 01/20/2023]
Abstract
Autophagy is an important biological process that is essential for the removal of damaged organelles and toxic or aggregated proteins by delivering them to the lysosome for degradation. Consequently, autophagy has become a primary target for the treatment of neurodegenerative diseases that involve aggregating proteins. In Huntington disease (HD), an expansion of the polyglutamine (polyQ) tract in the N-terminus of the huntingtin (HTT) protein leads to protein aggregation. However, HD is unique among the neurodegenerative proteinopathies in that autophagy is not only dysfunctional but wild type (wt) HTT also appears to play several roles in regulating the dynamics of autophagy. Herein, we attempt to integrate the recently described novel roles of wtHTT and altered autophagy in HD.
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Affiliation(s)
- Dale D O Martin
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
| | - Safia Ladha
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Dagmar E Ehrnhoefer
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics (CMMT), Department of Medical Genetics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.
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30
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Carroll B, Korolchuk VI, Sarkar S. Amino acids and autophagy: cross-talk and co-operation to control cellular homeostasis. Amino Acids 2014; 47:2065-88. [PMID: 24965527 DOI: 10.1007/s00726-014-1775-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 05/29/2014] [Indexed: 12/13/2022]
Abstract
Maintenance of amino acid homeostasis is important for healthy cellular function, metabolism and growth. Intracellular amino acid concentrations are dynamic; the high demand for protein synthesis must be met with constant dietary intake, followed by cellular influx, utilization and recycling of nutrients. Autophagy is a catabolic process via which superfluous or damaged proteins and organelles are delivered to the lysosome and degraded to release free amino acids into the cytoplasm. Furthermore, autophagy is specifically activated in response to amino acid starvation via two key signaling cascades: the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) and the general control nonderepressible 2 (GCN2) pathways. These pathways are key regulators of the integration between anabolic (amino acid depleting) and catabolic (such as autophagy which is amino acid replenishing) processes to ensure intracellular amino acid homeostasis. Here, we discuss the key roles that amino acids, along with energy (ATP, glucose) and oxygen, are playing in cellular growth and proliferation. We further explore how sophisticated methods are employed by cells to sense intracellular amino acid concentrations, how amino acids can act as a switch to dictate the temporal and spatial activation of anabolic and catabolic processes and how autophagy contributes to the replenishment of free amino acids, all to ensure cell survival. Relevance of these molecular processes to cellular and organismal physiology and pathology is also discussed.
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Affiliation(s)
- Bernadette Carroll
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL, UK
| | - Viktor I Korolchuk
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne, NE4 5PL, UK.
| | - Sovan Sarkar
- Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, 9 Cambridge Center, Cambridge, MA, 02142, USA.
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31
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Regulation of autophagy by mTOR-dependent and mTOR-independent pathways: autophagy dysfunction in neurodegenerative diseases and therapeutic application of autophagy enhancers. Biochem Soc Trans 2014; 41:1103-30. [PMID: 24059496 DOI: 10.1042/bst20130134] [Citation(s) in RCA: 269] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autophagy is an intracellular degradation pathway essential for cellular and energy homoeostasis. It functions in the clearance of misfolded proteins and damaged organelles, as well as recycling of cytosolic components during starvation to compensate for nutrient deprivation. This process is regulated by mTOR (mammalian target of rapamycin)-dependent and mTOR-independent pathways that are amenable to chemical perturbations. Several small molecules modulating autophagy have been identified that have potential therapeutic application in diverse human diseases, including neurodegeneration. Neurodegeneration-associated aggregation-prone proteins are predominantly degraded by autophagy and therefore stimulating this process with chemical inducers is beneficial in a wide range of transgenic disease models. Emerging evidence indicates that compromised autophagy contributes to the aetiology of various neurodegenerative diseases related to protein conformational disorders by causing the accumulation of mutant proteins and cellular toxicity. Combining the knowledge of autophagy dysfunction and the mechanism of drug action may thus be rational for designing targeted therapy. The present review describes the cellular signalling pathways regulating mammalian autophagy and highlights the potential therapeutic application of autophagy inducers in neurodegenerative disorders.
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