1
|
Bartman S, Coppotelli G, Ross JM. Mitochondrial Dysfunction: A Key Player in Brain Aging and Diseases. Curr Issues Mol Biol 2024; 46:1987-2026. [PMID: 38534746 DOI: 10.3390/cimb46030130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/28/2024] Open
Abstract
Mitochondria are thought to have become incorporated within the eukaryotic cell approximately 2 billion years ago and play a role in a variety of cellular processes, such as energy production, calcium buffering and homeostasis, steroid synthesis, cell growth, and apoptosis, as well as inflammation and ROS production. Considering that mitochondria are involved in a multitude of cellular processes, mitochondrial dysfunction has been shown to play a role within several age-related diseases, including cancers, diabetes (type 2), and neurodegenerative diseases, although the underlying mechanisms are not entirely understood. The significant increase in lifespan and increased incidence of age-related diseases over recent decades has confirmed the necessity to understand the mechanisms by which mitochondrial dysfunction impacts the process of aging and age-related diseases. In this review, we will offer a brief overview of mitochondria, along with structure and function of this important organelle. We will then discuss the cause and consequence of mitochondrial dysfunction in the aging process, with a particular focus on its role in inflammation, cognitive decline, and neurodegenerative diseases, such as Huntington's disease, Parkinson's disease, and Alzheimer's disease. We will offer insight into therapies and interventions currently used to preserve or restore mitochondrial functioning during aging and neurodegeneration.
Collapse
Affiliation(s)
- Sydney Bartman
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI 02881, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Giuseppe Coppotelli
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI 02881, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| | - Jaime M Ross
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI 02881, USA
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, Kingston, RI 02881, USA
| |
Collapse
|
2
|
Rademacher K, Nakamura K. Role of dopamine neuron activity in Parkinson's disease pathophysiology. Exp Neurol 2024; 373:114645. [PMID: 38092187 DOI: 10.1016/j.expneurol.2023.114645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 11/17/2023] [Accepted: 12/03/2023] [Indexed: 12/24/2023]
Abstract
Neural activity is finely tuned to produce normal behaviors, and disruptions in activity likely occur early in the course of many neurodegenerative diseases. However, how neural activity is altered, and how these changes influence neurodegeneration is poorly understood. Here, we focus on evidence that the activity of dopamine neurons is altered in Parkinson's disease (PD), either as a compensatory response to degeneration or as a result of circuit dynamics or pathologic proteins, based on available human data and studies in animal models of PD. We then discuss how this abnormal activity may augment other neurotoxic phenomena in PD, including mitochondrial deficits, protein aggregation and spread, dopamine toxicity, and excitotoxicity. A more complete picture of how activity is altered and the resulting effects on dopaminergic neuron health and function may inform future therapeutic interventions to target and protect dopamine neurons from degeneration.
Collapse
Affiliation(s)
- Katerina Rademacher
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, California, 94158, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA.; Graduate Program in Neuroscience, University of California San Francisco, San Francisco, California, 94158, USA
| | - Ken Nakamura
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, California, 94158, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA.; Graduate Program in Neuroscience, University of California San Francisco, San Francisco, California, 94158, USA; Graduate Program in Biomedical Sciences, University of California San Francisco, San Francisco, California, 94143, USA; Department of Neurology, University of California, San Francisco, San Francisco, California, 94158, USA.
| |
Collapse
|
3
|
Ratan Y, Rajput A, Pareek A, Pareek A, Jain V, Sonia S, Farooqui Z, Kaur R, Singh G. Advancements in Genetic and Biochemical Insights: Unraveling the Etiopathogenesis of Neurodegeneration in Parkinson's Disease. Biomolecules 2024; 14:73. [PMID: 38254673 PMCID: PMC10813470 DOI: 10.3390/biom14010073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/15/2023] [Accepted: 12/28/2023] [Indexed: 01/24/2024] Open
Abstract
Parkinson's disease (PD) is the second most prevalent neurodegenerative movement disorder worldwide, which is primarily characterized by motor impairments. Even though multiple hypotheses have been proposed over the decades that explain the pathogenesis of PD, presently, there are no cures or promising preventive therapies for PD. This could be attributed to the intricate pathophysiology of PD and the poorly understood molecular mechanism. To address these challenges comprehensively, a thorough disease model is imperative for a nuanced understanding of PD's underlying pathogenic mechanisms. This review offers a detailed analysis of the current state of knowledge regarding the molecular mechanisms underlying the pathogenesis of PD, with a particular emphasis on the roles played by gene-based factors in the disease's development and progression. This study includes an extensive discussion of the proteins and mutations of primary genes that are linked to PD, including α-synuclein, GBA1, LRRK2, VPS35, PINK1, DJ-1, and Parkin. Further, this review explores plausible mechanisms for DAergic neural loss, non-motor and non-dopaminergic pathologies, and the risk factors associated with PD. The present study will encourage the related research fields to understand better and analyze the current status of the biochemical mechanisms of PD, which might contribute to the design and development of efficacious and safe treatment strategies for PD in future endeavors.
Collapse
Affiliation(s)
- Yashumati Ratan
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India; (A.R.); (A.P.); (A.P.)
| | - Aishwarya Rajput
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India; (A.R.); (A.P.); (A.P.)
| | - Ashutosh Pareek
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India; (A.R.); (A.P.); (A.P.)
| | - Aaushi Pareek
- Department of Pharmacy, Banasthali Vidyapith, Banasthali 304022, Rajasthan, India; (A.R.); (A.P.); (A.P.)
| | - Vivek Jain
- Department of Pharmaceutical Sciences, Mohan Lal Sukhadia University, Udaipur 313001, Rajasthan, India;
| | - Sonia Sonia
- Department of Pharmaceutical Sciences, Guru Nanak Dev University, Amritsar 143005, Punjab, India;
| | - Zeba Farooqui
- Department of Biomedical Engineering, University of Illinois Chicago, Chicago, IL 60607, USA;
| | - Ranjeet Kaur
- Adesh Institute of Dental Sciences and Research, Bathinda 151101, Punjab, India;
| | - Gurjit Singh
- Department of Biomedical Engineering, University of Illinois Chicago, Chicago, IL 60607, USA;
| |
Collapse
|
4
|
Averina OA, Kuznetsova SA, Permyakov OA, Sergiev PV. Animal Models of Mitochondrial Diseases Associated with Nuclear Gene Mutations. Acta Naturae 2023; 15:4-22. [PMID: 38234606 PMCID: PMC10790356 DOI: 10.32607/actanaturae.25442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 10/05/2023] [Indexed: 01/19/2024] Open
Abstract
Mitochondrial diseases (MDs) associated with nuclear gene mutations are part of a large group of inherited diseases caused by the suppression of energy metabolism. These diseases are of particular interest, because nuclear genes encode not only most of the structural proteins of the oxidative phosphorylation system (OXPHOS), but also all the proteins involved in the OXPHOS protein import from the cytoplasm and their assembly in mitochondria. Defects in any of these proteins can lead to functional impairment of the respiratory chain, including dysfunction of complex I that plays a central role in cellular respiration and oxidative phosphorylation, which is the most common cause of mitopathologies. Mitochondrial diseases are characterized by an early age of onset and a progressive course and affect primarily energy-consuming tissues and organs. The treatment of MDs should be initiated as soon as possible, but the diagnosis of mitopathologies is extremely difficult because of their heterogeneity and overlapping clinical features. The molecular pathogenesis of mitochondrial diseases is investigated using animal models: i.e. animals carrying mutations causing MD symptoms in humans. The use of mutant animal models opens new opportunities in the study of genes encoding mitochondrial proteins, as well as the molecular mechanisms of mitopathology development, which is necessary for improving diagnosis and developing approaches to drug therapy. In this review, we present the most recent information on mitochondrial diseases associated with nuclear gene mutations and animal models developed to investigate them.
Collapse
Affiliation(s)
- O. A. Averina
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - S. A. Kuznetsova
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - O. A. Permyakov
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| | - P. V. Sergiev
- Institute of Functional Genomics, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
- Department of Chemistry, Lomonosov Moscow State University, Moscow, 119991 Russian Federation
| |
Collapse
|
5
|
Mise K, Long J, Galvan DL, Ye Z, Fan G, Serysheva II, Moore TI, Wada J, Schumacker PT, Chang BH, Danesh FR. NDUFS4 Regulates Cristae Remodeling in Diabetic Kidney Disease. RESEARCH SQUARE 2023:rs.3.rs-3070079. [PMID: 37461606 PMCID: PMC10350115 DOI: 10.21203/rs.3.rs-3070079/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2023]
Abstract
The mitochondrial electron transport chain (ETC) is a highly adaptive process to meet metabolic demands of the cell, and its dysregulation has been associated with diverse clinical pathologies. However, the role and nature of impaired ETC in kidney diseases remains poorly understood. Here, we generated diabetic mice with podocyte-specific overexpression of Ndufs4, an accessory subunit of mitochondrial complex I, as a model to investigate the role of ETC integrity in diabetic kidney disease (DKD). We find that these conditional mice exhibit significant improvements in cristae morphology, mitochondrial dynamics, and albuminuria. By coupling proximity labeling with super-resolution imaging, we also identify the role of cristae shaping proteins in linking NDUFS4 with improved cristae morphology. Taken together, we discover the central role of NDUFS4 as a powerful regulator of cristae remodeling, respiratory supercomplexes assembly, and mitochondrial ultrastructure in vitro and in vivo. We propose that targeting NDUFS4 represents a promising approach to slow the progression of DKD.
Collapse
Affiliation(s)
- Koki Mise
- Section of Nephrology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- Department of Nephrology, Rheumatology, Endocrinology & Metabolism, Okayama University Graduate School of Medicine, Dentistry & Pharmaceutical Sciences, Okayama, Japan
| | - Jianyin Long
- Section of Nephrology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Daniel L. Galvan
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Zengchun Ye
- Division of Nephrology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Guizhen Fan
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Irina I. Serysheva
- Department of Biochemistry and Molecular Biology, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Travis I. Moore
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, Texas
| | - Jun Wada
- Department of Nephrology, Rheumatology, Endocrinology & Metabolism, Okayama University Graduate School of Medicine, Dentistry & Pharmaceutical Sciences, Okayama, Japan
| | - Paul T. Schumacker
- Department of Pediatrics, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Benny H. Chang
- Section of Nephrology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Farhad R. Danesh
- Section of Nephrology, The University of Texas MD Anderson Cancer Center, Houston, Texas
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX
| |
Collapse
|
6
|
García-Beltrán O, Urrutia PJ, Núñez MT. On the Chemical and Biological Characteristics of Multifunctional Compounds for the Treatment of Parkinson's Disease. Antioxidants (Basel) 2023; 12:antiox12020214. [PMID: 36829773 PMCID: PMC9952574 DOI: 10.3390/antiox12020214] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/12/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Protein aggregation, mitochondrial dysfunction, iron dyshomeostasis, increased oxidative damage and inflammation are pathognomonic features of Parkinson's disease (PD) and other neurodegenerative disorders characterized by abnormal iron accumulation. Moreover, the existence of positive feed-back loops between these pathological components, which accelerate, and sometimes make irreversible, the neurodegenerative process, is apparent. At present, the available treatments for PD aim to relieve the symptoms, thus improving quality of life, but no treatments to stop the progression of the disease are available. Recently, the use of multifunctional compounds with the capacity to attack several of the key components of neurodegenerative processes has been proposed as a strategy to slow down the progression of neurodegenerative processes. For the treatment of PD specifically, the necessary properties of new-generation drugs should include mitochondrial destination, the center of iron-reactive oxygen species interaction, iron chelation capacity to decrease iron-mediated oxidative damage, the capacity to quench free radicals to decrease the risk of ferroptotic neuronal death, the capacity to disrupt α-synuclein aggregates and the capacity to decrease inflammatory conditions. Desirable additional characteristics are dopaminergic neurons to lessen unwanted secondary effects during long-term treatment, and the inhibition of the MAO-B and COMPT activities to increase intraneuronal dopamine content. On the basis of the published evidence, in this work, we review the molecular basis underlying the pathological events associated with PD and the clinical trials that have used single-target drugs to stop the progress of the disease. We also review the current information on multifunctional compounds that may be used for the treatment of PD and discuss the chemical characteristics that underlie their functionality. As a projection, some of these compounds or modifications could be used to treat diseases that share common pathology features with PD, such as Friedreich's ataxia, Multiple sclerosis, Huntington disease and Alzheimer's disease.
Collapse
Affiliation(s)
- Olimpo García-Beltrán
- Facultad de Ciencias Naturales y Matemáticas, Universidad de Ibagué, Carrera 22 Calle 67, Ibagué 730002, Colombia
- Centro Integrativo de Biología y Química Aplicada (CIBQA), Universidad Bernardo O’Higgins, General Gana 1702, Santiago 8370854, Chile
- Correspondence:
| | - Pamela J. Urrutia
- Faculty of Medicine and Science, Universidad San Sebastián, Lota 2465, Santiago 7510157, Chile
| | - Marco T. Núñez
- Faculty of Sciences, Universidad de Chile, Las Palmeras 3425, Santiago 7800024, Chile
| |
Collapse
|
7
|
Mahony C, O'Ryan C. A molecular framework for autistic experiences: Mitochondrial allostatic load as a mediator between autism and psychopathology. Front Psychiatry 2022; 13:985713. [PMID: 36506457 PMCID: PMC9732262 DOI: 10.3389/fpsyt.2022.985713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 11/07/2022] [Indexed: 11/27/2022] Open
Abstract
Molecular autism research is evolving toward a biopsychosocial framework that is more informed by autistic experiences. In this context, research aims are moving away from correcting external autistic behaviors and toward alleviating internal distress. Autism Spectrum Conditions (ASCs) are associated with high rates of depression, suicidality and other comorbid psychopathologies, but this relationship is poorly understood. Here, we integrate emerging characterizations of internal autistic experiences within a molecular framework to yield insight into the prevalence of psychopathology in ASC. We demonstrate that descriptions of social camouflaging and autistic burnout resonate closely with the accepted definitions for early life stress (ELS) and chronic adolescent stress (CAS). We propose that social camouflaging could be considered a distinct form of CAS that contributes to allostatic overload, culminating in a pathophysiological state that is experienced as autistic burnout. Autistic burnout is thought to contribute to psychopathology via psychological and physiological mechanisms, but these remain largely unexplored by molecular researchers. Building on converging fields in molecular neuroscience, we discuss the substantial evidence implicating mitochondrial dysfunction in ASC to propose a novel role for mitochondrial allostatic load in the relationship between autism and psychopathology. An interplay between mitochondrial, neuroimmune and neuroendocrine signaling is increasingly implicated in stress-related psychopathologies, and these molecular players are also associated with neurodevelopmental, neurophysiological and neurochemical aspects of ASC. Together, this suggests an increased exposure and underlying molecular susceptibility to ELS that increases the risk of psychopathology in ASC. This article describes an integrative framework shaped by autistic experiences that highlights novel avenues for molecular research into mechanisms that directly affect the quality of life and wellbeing of autistic individuals. Moreover, this framework emphasizes the need for increased access to diagnoses, accommodations, and resources to improve mental health outcomes in autism.
Collapse
Affiliation(s)
| | - Colleen O'Ryan
- Department of Molecular and Cell Biology, University of Cape Town, Cape Town, South Africa
| |
Collapse
|
8
|
Lang M, Grünewald A, Pramstaller PP, Hicks AA, Pichler I. A genome on shaky ground: exploring the impact of mitochondrial DNA integrity on Parkinson's disease by highlighting the use of cybrid models. Cell Mol Life Sci 2022; 79:283. [PMID: 35513611 PMCID: PMC9072496 DOI: 10.1007/s00018-022-04304-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/01/2022] [Accepted: 04/12/2022] [Indexed: 11/29/2022]
Abstract
Mitochondria play important roles in the regulation of key cellular processes, including energy metabolism, oxidative stress response, and signaling towards cell death or survival, and are distinguished by carrying their own genome (mtDNA). Mitochondrial dysfunction has emerged as a prominent cellular mechanism involved in neurodegeneration, including Parkinson’s disease (PD), a neurodegenerative movement disorder, characterized by progressive loss of dopaminergic neurons and the occurrence of proteinaceous Lewy body inclusions. The contribution of mtDNA variants to PD pathogenesis has long been debated and is still not clearly answered. Cytoplasmic hybrid (cybrid) cell models provided evidence for a contribution of mtDNA variants to the PD phenotype. However, conclusive evidence of mtDNA mutations as genetic cause of PD is still lacking. Several models have shown a role of somatic, rather than inherited mtDNA variants in the impairment of mitochondrial function and neurodegeneration. Accordingly, several nuclear genes driving inherited forms of PD are linked to mtDNA quality control mechanisms, and idiopathic as well as familial PD tissues present increased mtDNA damage. In this review, we highlight the use of cybrids in this PD research field and summarize various aspects of how and to what extent mtDNA variants may contribute to the etiology of PD.
Collapse
Affiliation(s)
- Martin Lang
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy.
| | - Anne Grünewald
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, L-4362, Esch-sur-Alzette, Luxembourg
| | - Peter P Pramstaller
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy.,Department of Neurology, University Medical Center Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | - Andrew A Hicks
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
| | - Irene Pichler
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy.
| |
Collapse
|
9
|
van de Wal MAE, Adjobo-Hermans MJW, Keijer J, Schirris TJJ, Homberg JR, Wieckowski MR, Grefte S, van Schothorst EM, van Karnebeek C, Quintana A, Koopman WJH. Ndufs4 knockout mouse models of Leigh syndrome: pathophysiology and intervention. Brain 2022. [PMID: 34849584 DOI: 10.1093/brain/awab426%jbrain] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Mitochondria are small cellular constituents that generate cellular energy (ATP) by oxidative phosphorylation (OXPHOS). Dysfunction of these organelles is linked to a heterogeneous group of multisystemic disorders, including diabetes, cancer, ageing-related pathologies and rare mitochondrial diseases. With respect to the latter, mutations in subunit-encoding genes and assembly factors of the first OXPHOS complex (complex I) induce isolated complex I deficiency and Leigh syndrome. This syndrome is an early-onset, often fatal, encephalopathy with a variable clinical presentation and poor prognosis due to the lack of effective intervention strategies. Mutations in the nuclear DNA-encoded NDUFS4 gene, encoding the NADH:ubiquinone oxidoreductase subunit S4 (NDUFS4) of complex I, induce 'mitochondrial complex I deficiency, nuclear type 1' (MC1DN1) and Leigh syndrome in paediatric patients. A variety of (tissue-specific) Ndufs4 knockout mouse models were developed to study the Leigh syndrome pathomechanism and intervention testing. Here, we review and discuss the role of complex I and NDUFS4 mutations in human mitochondrial disease, and review how the analysis of Ndufs4 knockout mouse models has generated new insights into the MC1ND1/Leigh syndrome pathomechanism and its therapeutic targeting.
Collapse
Affiliation(s)
- Melissa A E van de Wal
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | | | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Tom J J Schirris
- Department of Pharmacology and Toxicology, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Sander Grefte
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | | | - Clara van Karnebeek
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
- Department of Pediatrics, Emma Personalized Medicine Center, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Department of Human Genetics, Emma Personalized Medicine Center, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Albert Quintana
- Mitochondrial Neuropathology Laboratory, Institut de Neurociències and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Werner J H Koopman
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| |
Collapse
|
10
|
Mennuni M, Filograna R, Felser A, Bonekamp NA, Giavalisco P, Lytovchenko O, Larsson N. Metabolic resistance to the inhibition of mitochondrial transcription revealed by CRISPR-Cas9 screen. EMBO Rep 2022; 23:e53054. [PMID: 34779571 PMCID: PMC8728608 DOI: 10.15252/embr.202153054] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 10/12/2021] [Accepted: 10/19/2021] [Indexed: 12/20/2022] Open
Abstract
Cancer cells depend on mitochondria to sustain their increased metabolic need and mitochondria therefore constitute possible targets for cancer treatment. We recently developed small-molecule inhibitors of mitochondrial transcription (IMTs) that selectively impair mitochondrial gene expression. IMTs have potent antitumor properties in vitro and in vivo, without affecting normal tissues. Because therapy-induced resistance is a major constraint to successful cancer therapy, we investigated mechanisms conferring resistance to IMTs. We employed a CRISPR-Cas9 (clustered regularly interspaced short palindromic repeats)-(CRISP-associated protein 9) whole-genome screen to determine pathways conferring resistance to acute IMT1 treatment. Loss of genes belonging to von Hippel-Lindau (VHL) and mammalian target of rapamycin complex 1 (mTORC1) pathways caused resistance to acute IMT1 treatment and the relevance of these pathways was confirmed by chemical modulation. We also generated cells resistant to chronic IMT treatment to understand responses to persistent mitochondrial gene expression impairment. We report that IMT1-acquired resistance occurs through a compensatory increase of mitochondrial DNA (mtDNA) expression and cellular metabolites. We found that mitochondrial transcription factor A (TFAM) downregulation and inhibition of mitochondrial translation impaired survival of resistant cells. The identified susceptibility and resistance mechanisms to IMTs may be relevant for different types of mitochondria-targeted therapies.
Collapse
Affiliation(s)
- Mara Mennuni
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Roberta Filograna
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Andrea Felser
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
- University Institute of Clinical ChemistryBern University HospitalBernSwitzerland
| | - Nina A Bonekamp
- Mitochondrial Biology GroupMax Planck Institute for Biology of AgeingCologneGermany
- Department of NeuroanatomyMannheim Center for Translational Neuroscience (MCTN)Medical Faculty MannheimHeidelberg UniversityMannheimGermany
| | - Patrick Giavalisco
- Metabolomics Core FacilityMax Planck Institute for Biology of AgeingCologneGermany
| | - Oleksandr Lytovchenko
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| | - Nils‐Göran Larsson
- Department of Medical Biochemistry and BiophysicsKarolinska InstitutetStockholmSweden
| |
Collapse
|
11
|
van de Wal M, Adjobo-Hermans M, Keijer J, Schirris T, Homberg J, Wieckowski MR, Grefte S, van Schothorst EM, van Karnebeek C, Quintana A, Koopman WJH. Ndufs4 knockout mouse models of Leigh syndrome: pathophysiology and intervention. Brain 2021; 145:45-63. [PMID: 34849584 PMCID: PMC8967107 DOI: 10.1093/brain/awab426] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/25/2021] [Accepted: 11/11/2021] [Indexed: 11/14/2022] Open
Abstract
Mitochondria are small cellular constituents that generate cellular energy (ATP) by oxidative phosphorylation (OXPHOS). Dysfunction of these organelles is linked to a heterogeneous group of multisystemic disorders, including diabetes, cancer, ageing-related pathologies and rare mitochondrial diseases. With respect to the latter, mutations in subunit-encoding genes and assembly factors of the first OXPHOS complex (complex I) induce isolated complex I deficiency and Leigh syndrome. This syndrome is an early-onset, often fatal, encephalopathy with a variable clinical presentation and poor prognosis due to the lack of effective intervention strategies. Mutations in the nuclear DNA-encoded NDUFS4 gene, encoding the NADH:ubiquinone oxidoreductase subunit S4 (NDUFS4) of complex I, induce ‘mitochondrial complex I deficiency, nuclear type 1’ (MC1DN1) and Leigh syndrome in paediatric patients. A variety of (tissue-specific) Ndufs4 knockout mouse models were developed to study the Leigh syndrome pathomechanism and intervention testing. Here, we review and discuss the role of complex I and NDUFS4 mutations in human mitochondrial disease, and review how the analysis of Ndufs4 knockout mouse models has generated new insights into the MC1ND1/Leigh syndrome pathomechanism and its therapeutic targeting.
Collapse
Affiliation(s)
- Melissa van de Wal
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Merel Adjobo-Hermans
- Department of Biochemistry (286), RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Tom Schirris
- Department of Pharmacology and Toxicology, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Judith Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Sander Grefte
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | | | - Clara van Karnebeek
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands.,Department of Pediatrics, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Albert Quintana
- Mitochondrial Neuropathology Laboratory, Institut de Neurociències and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Werner J H Koopman
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands.,Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| |
Collapse
|
12
|
|
13
|
Pirooznia SK, Rosenthal LS, Dawson VL, Dawson TM. Parkinson Disease: Translating Insights from Molecular Mechanisms to Neuroprotection. Pharmacol Rev 2021; 73:33-97. [PMID: 34663684 DOI: 10.1124/pharmrev.120.000189] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Parkinson disease (PD) used to be considered a nongenetic condition. However, the identification of several autosomal dominant and recessive mutations linked to monogenic PD has changed this view. Clinically manifest PD is then thought to occur through a complex interplay between genetic mutations, many of which have incomplete penetrance, and environmental factors, both neuroprotective and increasing susceptibility, which variably interact to reach a threshold over which PD becomes clinically manifested. Functional studies of PD gene products have identified many cellular and molecular pathways, providing crucial insights into the nature and causes of PD. PD originates from multiple causes and a range of pathogenic processes at play, ultimately culminating in nigral dopaminergic loss and motor dysfunction. An in-depth understanding of these complex and possibly convergent pathways will pave the way for therapeutic approaches to alleviate the disease symptoms and neuroprotective strategies to prevent disease manifestations. This review is aimed at providing a comprehensive understanding of advances made in PD research based on leveraging genetic insights into the pathogenesis of PD. It further discusses novel perspectives to facilitate identification of critical molecular pathways that are central to neurodegeneration that hold the potential to develop neuroprotective and/or neurorestorative therapeutic strategies for PD. SIGNIFICANCE STATEMENT: A comprehensive review of PD pathophysiology is provided on the complex interplay of genetic and environmental factors and biologic processes that contribute to PD pathogenesis. This knowledge identifies new targets that could be leveraged into disease-modifying therapies to prevent or slow neurodegeneration in PD.
Collapse
Affiliation(s)
- Sheila K Pirooznia
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering (S.K.P., V.L.D., T.M.D.), Departments of Neurology (S.K.P., L.S.R., V.L.D., T.M.D.), Departments of Physiology (V.L.D.), Solomon H. Snyder Department of Neuroscience (V.L.D., T.M.D.), Department of Pharmacology and Molecular Sciences (T.M.D.), Johns Hopkins University School of Medicine, Baltimore, Maryland; Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.); and Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.)
| | - Liana S Rosenthal
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering (S.K.P., V.L.D., T.M.D.), Departments of Neurology (S.K.P., L.S.R., V.L.D., T.M.D.), Departments of Physiology (V.L.D.), Solomon H. Snyder Department of Neuroscience (V.L.D., T.M.D.), Department of Pharmacology and Molecular Sciences (T.M.D.), Johns Hopkins University School of Medicine, Baltimore, Maryland; Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.); and Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.)
| | - Valina L Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering (S.K.P., V.L.D., T.M.D.), Departments of Neurology (S.K.P., L.S.R., V.L.D., T.M.D.), Departments of Physiology (V.L.D.), Solomon H. Snyder Department of Neuroscience (V.L.D., T.M.D.), Department of Pharmacology and Molecular Sciences (T.M.D.), Johns Hopkins University School of Medicine, Baltimore, Maryland; Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.); and Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.)
| | - Ted M Dawson
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering (S.K.P., V.L.D., T.M.D.), Departments of Neurology (S.K.P., L.S.R., V.L.D., T.M.D.), Departments of Physiology (V.L.D.), Solomon H. Snyder Department of Neuroscience (V.L.D., T.M.D.), Department of Pharmacology and Molecular Sciences (T.M.D.), Johns Hopkins University School of Medicine, Baltimore, Maryland; Adrienne Helis Malvin Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.); and Diana Helis Henry Medical Research Foundation, New Orleans, Louisiana (S.K.P., V.L.D., T.M.D.)
| |
Collapse
|
14
|
Mitochondrial dysfunction in adult midbrain dopamine neurons triggers an early immune response. PLoS Genet 2021; 17:e1009822. [PMID: 34570766 PMCID: PMC8496783 DOI: 10.1371/journal.pgen.1009822] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 10/07/2021] [Accepted: 09/10/2021] [Indexed: 01/11/2023] Open
Abstract
Dopamine (DA) neurons of the midbrain are at risk to become affected by mitochondrial damage over time and mitochondrial defects have been frequently reported in Parkinson’s disease (PD) patients. However, the causal contribution of adult-onset mitochondrial dysfunction to PD remains uncertain. Here, we developed a mouse model lacking Mitofusin 2 (MFN2), a key regulator of mitochondrial network homeostasis, in adult midbrain DA neurons. The knockout mice develop severe and progressive DA neuron-specific mitochondrial dysfunction resulting in neurodegeneration and parkinsonism. To gain further insights into pathophysiological events, we performed transcriptomic analyses of isolated DA neurons and found that mitochondrial dysfunction triggers an early onset immune response, which precedes mitochondrial swelling, mtDNA depletion, respiratory chain deficiency and cell death. Our experiments show that the immune response is an early pathological event when mitochondrial dysfunction is induced in adult midbrain DA neurons and that neuronal death may be promoted non-cell autonomously by the cross-talk and activation of surrounding glial cells. Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by progressive loss of dopamine (DA)-producing neurons and strongly compromised motor performance. Multiple observations suggest that DA neurons are particularly prone to acquire mitochondrial damage in adult life. This acquired mitochondrial dysfunction likely impairs DA neuron function and contributes to cell death. To study the consequences of adult-onset mitochondrial dysfunction in DA neurons, we generated a conditional activatable knockout mouse model lacking Mitofusin 2, a key regulator of mitochondrial homeostasis. This animal model allows the induction of mitochondrial dysfunction selectively in adult DA neurons and leads to motor defects and the typical pattern of neurodegeneration seen in PD. By studying gene expression in isolated DA neurons at early disease stages and by using in situ approaches on brain sections, we report an early onset of an inflammatory response. Inflammation is present already when the mutant DA neurons display the first signs of mitochondrial fragmentation and precedes the onset of respiratory chain dysfunction and neurodegeneration. The inflammatory response in DA neurons and activation of surrounding glia thus likely exacerbates or drives the neurodegenerative process in this animal model of adult-onset PD.
Collapse
|
15
|
Kaur I, Behl T, Sehgal A, Singh S, Sharma N, Aleya L, Bungau S. Connecting the dots between mitochondrial dysfunction and Parkinson's disorder: focus mitochondria-targeting therapeutic paradigm in mitigating the disease severity. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:37060-37081. [PMID: 34053042 DOI: 10.1007/s11356-021-14619-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 05/25/2021] [Indexed: 06/12/2023]
Abstract
Mitochondria are unique cell organelles, which exhibit multifactorial roles in numerous cell physiological processes, significantly preserving the integrity of neural synaptic interconnections, mediating ATP production, and regulating apoptotic signaling pathways and calcium homeostasis. Multiple neurological disorders occur as a consequence of impaired mitochondrial functioning, with greater sensitivity of dopaminergic (DA) neurons to mitochondrial dysfunction, due to oxidative nature and low mitochondrial mass, thus supporting the contribution of mitochondrial impairment in Parkinson's disorder (neuronal damage due to curbed dopamine levels). The pathophysiology of the second most common disorder, PD, is potentiated by various mitochondrial homeostasis regulating genes, as discussed in the review. The PD symptoms are known to be aggravated by multiple mitochondria-linked alterations, like reactive oxygen species (ROS) production, Ca2+ buffering, imbalanced mitochondrial dynamics (fission, fusion, mitophagy), biogenetic dysfunctions, disrupted mitochondrial membrane potential (MMP), protein aggregation, neurotoxins, and genetic mutations, which manifest the central involvement of unhealthy mitochondria in neurodegeneration, resulting in retarded DA neurons in region of substantia nigra pars compacta (SNpc), causing PD. Furthermore, the review tends to target altered mitochondrial components, like oxidative stress, inflammation, biogenetic alterations, impaired dynamics, uncontrolled homeostasis, and genetic mutations, to provide a sustainable and reliable alternative in PD therapeutics and to overcome the pitfalls of conventional therapeutic agents. Therefore, the authors elaborate the relationship between PD pathogenesis and mitochondrial dysfunctions, followed by a suitable mitochondria-targeting therapeutic portfolio, as well as future considerations, aiding the researchers to investigate novel strategies to mitigate the severity of the disease.
Collapse
Affiliation(s)
- Ishnoor Kaur
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Tapan Behl
- Chitkara College of Pharmacy, Chitkara University, Punjab, India.
| | - Aayush Sehgal
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Sukhbir Singh
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Neelam Sharma
- Chitkara College of Pharmacy, Chitkara University, Punjab, India
| | - Lotfi Aleya
- Chrono-Environment Laboratory, UMR CNRS 6249, Bourgogne Franche-Comté University, Besançon, France
| | - Simona Bungau
- Department of Pharmacy, Faculty of Medicine and Pharmacy, University of Oradea, Oradea, Romania
| |
Collapse
|
16
|
Terburgh K, Coetzer J, Lindeque JZ, van der Westhuizen FH, Louw R. Aberrant BCAA and glutamate metabolism linked to regional neurodegeneration in a mouse model of Leigh syndrome. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166082. [PMID: 33486097 DOI: 10.1016/j.bbadis.2021.166082] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/23/2020] [Accepted: 01/16/2021] [Indexed: 02/07/2023]
Abstract
The dysfunction of respiratory chain complex I (CI) is the most common form of mitochondrial disease that most often presents as Leigh syndrome (LS) in children - a severe neurometabolic disorder defined by progressive focal lesions in specific brain regions. The mechanisms underlying this region-specific vulnerability to CI deficiency, however, remain elusive. Here, we examined brain regional respiratory chain enzyme activities and metabolic profiles in a mouse model of LS with global CI deficiency to gain insight into regional vulnerability to neurodegeneration. One lesion-resistant and three lesion-prone brain regions were investigated in Ndufs4 knockout (KO) mice at the late stage of LS. Enzyme assays confirmed significantly decreased (60-80%) CI activity in all investigated KO brain regions, with the lesion-resistant region displaying the highest residual CI activity (38% of wild type). A higher residual CI activity, and a less perturbed NADH/NAD+ ratio, correlate with less severe metabolic perturbations in KO brain regions. Moreover, less perturbed BCAA oxidation and increased glutamate oxidation seem to distinguish lesion-resistant from -prone KO brain regions, thereby identifying key areas of metabolism to target in future therapeutic intervention studies.
Collapse
Affiliation(s)
- Karin Terburgh
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Janeé Coetzer
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Jeremy Z Lindeque
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Francois H van der Westhuizen
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa
| | - Roan Louw
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), South Africa.
| |
Collapse
|
17
|
Clark EH, Vázquez de la Torre A, Hoshikawa T, Briston T. Targeting mitophagy in Parkinson's disease. J Biol Chem 2021; 296:100209. [PMID: 33372898 PMCID: PMC7948953 DOI: 10.1074/jbc.rev120.014294] [Citation(s) in RCA: 59] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 12/22/2022] Open
Abstract
The genetics and pathophysiology of Parkinson's disease (PD) strongly implicate mitochondria in disease aetiology. Elegant studies over the last two decades have elucidated complex molecular signaling governing the identification and removal of dysfunctional mitochondria from the cell, a process of mitochondrial quality control known as mitophagy. Mitochondrial deficits and specifically reduced mitophagy are evident in both sporadic and familial PD. Mendelian genetics attributes loss-of-function mutations in key mitophagy regulators PINK1 and Parkin to early-onset PD. Pharmacologically enhancing mitophagy and accelerating the removal of damaged mitochondria are of interest for developing a disease-modifying PD therapeutic. However, despite significant understanding of both PINK1-Parkin-dependent and -independent mitochondrial quality control pathways, the therapeutic potential of targeting mitophagy remains to be fully explored. Here, we provide a summary of the genetic evidence supporting the role for mitophagy failure as a pathogenic mechanism in PD. We assess the tractability of mitophagy pathways and prospects for drug discovery and consider intervention points for mitophagy enhancement. We explore the numerous hit molecules beginning to emerge from high-content/high-throughput screening as well as the biochemical and phenotypic assays that enabled these screens. The chemical and biological properties of these reference compounds suggest many could be used to interrogate and perturb mitochondrial biology to validate promising drug targets. Finally, we address key considerations and challenges in achieving preclinical proof-of-concept, including in vivo mitophagy reporter methodologies and disease models, as well as patient stratification and biomarker development for mitochondrial forms of the disease.
Collapse
Affiliation(s)
- Emily H Clark
- Hatfield Research Laboratories, Neurology Innovation Centre, Eisai Ltd, Hatfield, United Kingdom
| | | | - Tamaki Hoshikawa
- Hatfield Research Laboratories, Neurology Innovation Centre, Eisai Ltd, Hatfield, United Kingdom
| | - Thomas Briston
- Hatfield Research Laboratories, Neurology Innovation Centre, Eisai Ltd, Hatfield, United Kingdom.
| |
Collapse
|
18
|
Zampese E, Surmeier DJ. Calcium, Bioenergetics, and Parkinson's Disease. Cells 2020; 9:cells9092045. [PMID: 32911641 PMCID: PMC7564460 DOI: 10.3390/cells9092045] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/04/2020] [Accepted: 09/07/2020] [Indexed: 12/12/2022] Open
Abstract
Degeneration of substantia nigra (SN) dopaminergic (DAergic) neurons is responsible for the core motor deficits of Parkinson’s disease (PD). These neurons are autonomous pacemakers that have large cytosolic Ca2+ oscillations that have been linked to basal mitochondrial oxidant stress and turnover. This review explores the origin of Ca2+ oscillations and their role in the control of mitochondrial respiration, bioenergetics, and mitochondrial oxidant stress.
Collapse
|
19
|
Wu H, Ke M, Deng Y. Proteome alterations in brains of KKAy diabetic mice imply the underling molecular links between diabetes and Parkinson's disease. Acta Biochim Biophys Sin (Shanghai) 2020; 52:695-697. [PMID: 32393960 DOI: 10.1093/abbs/gmaa033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 11/19/2019] [Accepted: 11/07/2019] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hanyan Wu
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
- Beijing Institute of Drug Control, Beijing 102206, China
| | - Ming Ke
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| | - Yulin Deng
- School of Life Science, Beijing Institute of Technology, Beijing 100081, China
| |
Collapse
|
20
|
Adjobo-Hermans MJW, de Haas R, Willems PHGM, Wojtala A, van Emst-de Vries SE, Wagenaars JA, van den Brand M, Rodenburg RJ, Smeitink JAM, Nijtmans LG, Sazanov LA, Wieckowski MR, Koopman WJH. NDUFS4 deletion triggers loss of NDUFA12 in Ndufs4 -/- mice and Leigh syndrome patients: A stabilizing role for NDUFAF2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148213. [PMID: 32335026 DOI: 10.1016/j.bbabio.2020.148213] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 04/15/2020] [Accepted: 04/16/2020] [Indexed: 01/07/2023]
Abstract
Mutations in NDUFS4, which encodes an accessory subunit of mitochondrial oxidative phosphorylation (OXPHOS) complex I (CI), induce Leigh syndrome (LS). LS is a poorly understood pediatric disorder featuring brain-specific anomalies and early death. To study the LS pathomechanism, we here compared OXPHOS proteomes between various Ndufs4-/- mouse tissues. Ndufs4-/- animals displayed significantly lower CI subunit levels in brain/diaphragm relative to other tissues (liver/heart/kidney/skeletal muscle), whereas other OXPHOS subunit levels were not reduced. Absence of NDUFS4 induced near complete absence of the NDUFA12 accessory subunit, a 50% reduction in other CI subunit levels, and an increase in specific CI assembly factors. Among the latter, NDUFAF2 was most highly increased. Regarding NDUFS4, NDUFA12 and NDUFAF2, identical results were obtained in Ndufs4-/- mouse embryonic fibroblasts (MEFs) and NDUFS4-mutated LS patient cells. Ndufs4-/- MEFs contained active CI in situ but blue-native-PAGE highlighted that NDUFAF2 attached to an inactive CI subcomplex (CI-830) and inactive assemblies of higher MW. In NDUFA12-mutated LS patient cells, NDUFA12 absence did not reduce NDUFS4 levels but triggered NDUFAF2 association to active CI. BN-PAGE revealed no such association in LS patient fibroblasts with mutations in other CI subunit-encoding genes where NDUFAF2 was attached to CI-830 (NDUFS1, NDUFV1 mutation) or not detected (NDUFS7 mutation). Supported by enzymological and CI in silico structural analysis, we conclude that absence of NDUFS4 induces near complete absence of NDUFA12 but not vice versa, and that NDUFAF2 stabilizes active CI in Ndufs4-/- mice and LS patient cells, perhaps in concert with mitochondrial inner membrane lipids.
Collapse
Affiliation(s)
- Merel J W Adjobo-Hermans
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Ria de Haas
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Peter H G M Willems
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | | | - Sjenet E van Emst-de Vries
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Jori A Wagenaars
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Mariel van den Brand
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Richard J Rodenburg
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Jan A M Smeitink
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | - Leo G Nijtmans
- Department of Pediatrics, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands
| | | | | | - Werner J H Koopman
- Department of Biochemistry, Radboud Institute for Molecular Life Sciences, Radboud Center for Mitochondrial Medicine, Radboudumc, Nijmegen, the Netherlands.
| |
Collapse
|
21
|
Emerging neuroprotective effect of metformin in Parkinson's disease: A molecular crosstalk. Pharmacol Res 2019; 152:104593. [PMID: 31843673 DOI: 10.1016/j.phrs.2019.104593] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 11/20/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023]
Abstract
Parkinson's disease (PD) is a devastating neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and Lewy pathology. PD is a major concern of today's aging population and has emerged as a global health burden. Despite the rapid advances in PD research over the past decades, the gold standard therapy provides only symptomatic relief and fails to halt disease progression. Therefore, exploring novel disease-modifying therapeutic strategies is highly demanded. Metformin, which is currently used as a first-line therapy for type 2 diabetes mellitus (T2DM), has recently demonstrated to exert a neuroprotective role in several neurodegenerative disorders including PD, both in vitro and in vivo. In this review, we explore the neuroprotective potential of metformin based on emerging evidence from pre-clinical and clinical studies. Regarding the underlying molecular mechanisms, metformin has been shown to inhibit α-synuclein (SNCA) phosphorylation and aggregation, prevent mitochondrial dysfunction, attenuate oxidative stress, modulate autophagy mainly via AMP-activated protein kinase (AMPK) activation, as well as prevent neurodegeneration and neuroinflammation. Overall, the neuroprotective effects of metformin in PD pathogenesis present a novel promising therapeutic strategy that might overcome the limitations of current PD treatment.
Collapse
|
22
|
Zeng XS, Geng WS, Jia JJ, Chen L, Zhang PP. Cellular and Molecular Basis of Neurodegeneration in Parkinson Disease. Front Aging Neurosci 2018; 10:109. [PMID: 29719505 PMCID: PMC5913322 DOI: 10.3389/fnagi.2018.00109] [Citation(s) in RCA: 124] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 04/03/2018] [Indexed: 12/15/2022] Open
Abstract
It has been 200 years since Parkinson disease (PD) was described by Dr. Parkinson in 1817. The disease is the second most common neurodegenerative disease characterized by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Although the pathogenesis of PD is still unknown, the research findings from scientists are conducive to understand the pathological mechanisms. It is well accepted that both genetic and environmental factors contribute to the onset of PD. In this review, we summarize the mutations of main seven genes (α-synuclein, LRRK2, PINK1, Parkin, DJ-1, VPS35 and GBA1) linked to PD, discuss the potential mechanisms for the loss of dopaminergic neurons (dopamine metabolism, mitochondrial dysfunction, endoplasmic reticulum stress, impaired autophagy, and deregulation of immunity) in PD, and expect the development direction for treatment of PD.
Collapse
Affiliation(s)
- Xian-Si Zeng
- College of Life Sciences, Institute for Conservation and Utilization of Agro-Bioresources in Dabie Mountains, Xinyang Normal University, Xinyang, China
| | - Wen-Shuo Geng
- College of Life Sciences, Institute for Conservation and Utilization of Agro-Bioresources in Dabie Mountains, Xinyang Normal University, Xinyang, China
| | - Jin-Jing Jia
- College of Life Sciences, Institute for Conservation and Utilization of Agro-Bioresources in Dabie Mountains, Xinyang Normal University, Xinyang, China
| | - Lei Chen
- College of Life Sciences, Institute for Conservation and Utilization of Agro-Bioresources in Dabie Mountains, Xinyang Normal University, Xinyang, China
| | - Peng-Peng Zhang
- College of Life Sciences, Institute for Conservation and Utilization of Agro-Bioresources in Dabie Mountains, Xinyang Normal University, Xinyang, China
| |
Collapse
|
23
|
Mo M, Xiao Y, Huang S, Cen L, Chen X, Zhang L, Luo Q, Li S, Yang X, Lin X, Xu P. MicroRNA expressing profiles in A53T mutant alpha-synuclein transgenic mice and Parkinsonian. Oncotarget 2018; 8:15-28. [PMID: 27965467 PMCID: PMC5352072 DOI: 10.18632/oncotarget.13905] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 12/01/2016] [Indexed: 12/23/2022] Open
Abstract
α-synuclein gene mutations can cause α-synuclein protein aggregation in the midbrain of Parkinson's disease (PD) patients. MicroRNAs (miRNAs) play a key role in the metabolism of α-synuclein but the mechanism involved in synucleinopathy remains unclear. In this study, we investigated the miRNA profiles in A53T-α-synuclein transgenic mice and analyzed the candidate miRNAs in the cerebrospinal fluid (CSF) of PD patients. The 12-month A53T-transgenic mouse displayed hyperactive movement and anxiolytic-like behaviors with α-synuclein aggregation in midbrain. A total of 317,759 total and 289,207 unique small RNA sequences in the midbrain of mice were identified by high-throughput deep sequencing. We found 644 miRNAs were significantly changed in the transgenic mice. Based on the conserved characteristic of miRNAs, we selected 11 candidates from the 40 remarkably expressed miRNAs and explored their expression in 44 CSF samples collected from PD patients. The results revealed that 11 microRNAs were differently expressed in CSF, emphatically as miR-144-5p, miR-200a-3p and miR-542-3p, which were dramatically up-regulated in both A53T-transgenic mice and PD patients, and had a helpful accuracy for the PD prediction. The ordered logistic regression analysis showed that the severity of PD has strong correlation with an up-expression of miR-144-5p, miR-200a-3p and miR-542-3p in CSF. Taken together, our data suggested that miRNAs in CSF, such as miR-144-5p, miR-200a-3p and miR-542-3p, may be useful to the PD diagnosis as potential biomarkers.
Collapse
Affiliation(s)
- Mingshu Mo
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangdong, China
| | - Yousheng Xiao
- Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, Guangdong, China
| | - Shuxuan Huang
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangdong, China
| | - Luan Cen
- Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, Guangdong, China
| | - Xiang Chen
- Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, Guangdong, China
| | - Limin Zhang
- Department of Neurology, The First Affiliated Hospital of Sun Yat-sen University, Guangdong, China
| | - Qin Luo
- Department of Neurology, The Third Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Shaomin Li
- Ann Romney Center for Neurologic Disease, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Xinling Yang
- Department of Neurology, The Third Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Xian Lin
- Department of Anatomy & Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangdong, China
| | - Pingyi Xu
- Department of Neurology, The First Affiliated Hospital of Guangzhou Medical University, Guangdong, China
| |
Collapse
|
24
|
Faustini G, Bono F, Valerio A, Pizzi M, Spano P, Bellucci A. Mitochondria and α-Synuclein: Friends or Foes in the Pathogenesis of Parkinson's Disease? Genes (Basel) 2017; 8:genes8120377. [PMID: 29292725 PMCID: PMC5748695 DOI: 10.3390/genes8120377] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/27/2017] [Accepted: 12/05/2017] [Indexed: 12/22/2022] Open
Abstract
Parkinson’s disease (PD) is a movement disorder characterized by dopaminergic nigrostriatal neuron degeneration and the formation of Lewy bodies (LB), pathological inclusions containing fibrils that are mainly composed of α-synuclein. Dopaminergic neurons, for their intrinsic characteristics, have a high energy demand that relies on the efficiency of the mitochondria respiratory chain. Dysregulations of mitochondria, deriving from alterations of complex I protein or oxidative DNA damage, change the trafficking, size and morphology of these organelles. Of note, these mitochondrial bioenergetics defects have been related to PD. A series of experimental evidence supports that α-synuclein physiological action is relevant for mitochondrial homeostasis, while its pathological aggregation can negatively impinge on mitochondrial function. It thus appears that imbalances in the equilibrium between the reciprocal modulatory action of mitochondria and α-synuclein can contribute to PD onset by inducing neuronal impairment. This review will try to highlight the role of physiological and pathological α-synuclein in the modulation of mitochondrial functions.
Collapse
Affiliation(s)
- Gaia Faustini
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy.
| | - Federica Bono
- Laboratory of Personalized and Preventive Medicine, University of Brescia, 25123 Brescia, Italy.
| | - Alessandra Valerio
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy.
| | - Marina Pizzi
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy.
| | - PierFranco Spano
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy.
| | - Arianna Bellucci
- Department of Molecular and Translational Medicine, University of Brescia, 25123 Brescia, Italy.
- Laboratory of Personalized and Preventive Medicine, University of Brescia, 25123 Brescia, Italy.
| |
Collapse
|
25
|
Letts JA, Sazanov LA. Clarifying the supercomplex: the higher-order organization of the mitochondrial electron transport chain. Nat Struct Mol Biol 2017; 24:800-808. [PMID: 28981073 DOI: 10.1038/nsmb.3460] [Citation(s) in RCA: 220] [Impact Index Per Article: 31.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 08/03/2017] [Indexed: 12/27/2022]
Abstract
The oxidative phosphorylation electron transport chain (OXPHOS-ETC) of the inner mitochondrial membrane is composed of five large protein complexes, named CI-CV. These complexes convert energy from the food we eat into ATP, a small molecule used to power a multitude of essential reactions throughout the cell. OXPHOS-ETC complexes are organized into supercomplexes (SCs) of defined stoichiometry: CI forms a supercomplex with CIII2 and CIV (SC I+III2+IV, known as the respirasome), as well as with CIII2 alone (SC I+III2). CIII2 forms a supercomplex with CIV (SC III2+IV) and CV forms dimers (CV2). Recent cryo-EM studies have revealed the structures of SC I+III2+IV and SC I+III2. Furthermore, recent work has shed light on the assembly and function of the SCs. Here we review and compare these recent studies and discuss how they have advanced our understanding of mitochondrial electron transport.
Collapse
Affiliation(s)
- James A Letts
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| |
Collapse
|
26
|
Abstract
Respiratory chain dysfunction plays an important role in human disease and aging. It is now well established that the individual respiratory complexes can be organized into supercomplexes, and structures for these macromolecular assemblies, determined by electron cryo-microscopy, have been described recently. Nevertheless, the reason why supercomplexes exist remains an enigma. The widely held view that they enhance catalysis by channeling substrates is challenged by both structural and biophysical information. Here, we evaluate and discuss data and hypotheses on the structures, roles, and assembly of respiratory-chain supercomplexes and propose a future research agenda to address unanswered questions.
Collapse
Affiliation(s)
- Dusanka Milenkovic
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany
| | - James N Blaza
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK
| | - Nils-Göran Larsson
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, 50931 Cologne, Germany; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 171 77 Stockholm, Sweden.
| | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge, CB2 0XY, UK.
| |
Collapse
|
27
|
Choi WS, Kim HW, Tronche F, Palmiter RD, Storm DR, Xia Z. Conditional deletion of Ndufs4 in dopaminergic neurons promotes Parkinson's disease-like non-motor symptoms without loss of dopamine neurons. Sci Rep 2017; 7:44989. [PMID: 28327638 PMCID: PMC5361188 DOI: 10.1038/srep44989] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 02/17/2017] [Indexed: 12/21/2022] Open
Abstract
Reduction of mitochondrial complex I activity is one of the major hypotheses for dopaminergic neuron death in Parkinson’s disease. However, reduction of complex I activity in all cells or selectively in dopaminergic neurons via conditional deletion of the Ndufs4 gene, a subunit of the mitochondrial complex I, does not cause dopaminergic neuron death or motor impairment. Here, we investigated the effect of reduced complex I activity on non-motor symptoms associated with Parkinson’s disease using conditional knockout (cKO) mice in which Ndufs4 was selectively deleted in dopaminergic neurons (Ndufs4 cKO). This conditional deletion of Ndufs4, which reduces complex I activity in dopamine neurons, did not cause a significant loss of dopaminergic neurons in substantia nigra pars compacta (SNpc), and there was no loss of dopaminergic neurites in striatum or amygdala. However, Ndufs4 cKO mice had a reduced amount of dopamine in the brain compared to control mice. Furthermore, even though motor behavior were not affected, Ndufs4 cKO mice showed non-motor symptoms experienced by many Parkinson’s disease patients including impaired cognitive function and increased anxiety-like behavior. These data suggest that mitochondrial complex I dysfunction in dopaminergic neurons promotes non-motor symptoms of Parkinson’s disease and reduces dopamine content in the absence of dopamine neuron loss.
Collapse
Affiliation(s)
- Won-Seok Choi
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA.,School of Biological Sciences and Technology, College of Natural Sciences, College of Medicine, Chonnam National University, Gwangju 61186, Korea
| | - Hyung-Wook Kim
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA.,College of Life Sciences, Sejong University, Seoul 05006, Korea
| | - François Tronche
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_CR18, Neuroscience, Paris-Seine, F-75005, Paris
| | - Richard D Palmiter
- Howard Hughes Medical Institute and Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Daniel R Storm
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Zhengui Xia
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98195, USA
| |
Collapse
|
28
|
Liu HF, Ho PWL, Leung GCT, Lam CSC, Pang SYY, Li L, Kung MHW, Ramsden DB, Ho SL. Combined LRRK2 mutation, aging and chronic low dose oral rotenone as a model of Parkinson's disease. Sci Rep 2017; 7:40887. [PMID: 28098219 PMCID: PMC5241661 DOI: 10.1038/srep40887] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 11/22/2016] [Indexed: 12/18/2022] Open
Abstract
Aging, genetics and environmental toxicity are important etiological factors in Parkinson’s disease (PD). However, its pathogenesis remains unclear. A major obstacle is the lack of an appropriate experimental model which incorporates genetic susceptibility, aging and prolonged environmental toxicity. Here, we explored the interplay amongst these factors using mutant LRRK2R1441G (leucine-rich-repeat-kinase-2) knockin mice. We found that mutant primary cortical and mesencephalic dopaminergic neurons were more susceptible to rotenone-induced ATP deficiency and cell death. Compared with wild-type controls, striatal synaptosomes isolated from young mutant mice exhibited significantly lower dopamine uptake after rotenone toxicity, due to reduced striatal synaptosomal mitochondria and synaptic vesicular proton pump protein (V-ATPase H) levels. Mutant mice developed greater locomotor deficits in open-field tests than wild-type mice following low oral rotenone doses given twice weekly over 50 weeks (half their lifespan). The increased locomotor deficit was associated with specific reduction in striatal mitochondrial Complex-I (NDUFS4) in rotenone-treated mutant but not in similarly treated wild-type mice. Our unique experimental model which incorporates genetic effect, natural aging and prolonged oral environmental toxicity administered to mutant knockin LRRK2 mice over half their life span, with observable and measurable phenotype, is invaluable in further studies of the pathogenic process and therapeutics of PD.
Collapse
Affiliation(s)
- Hui-Fang Liu
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong
| | - Philip Wing-Lok Ho
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong
| | | | - Colin Siu-Chi Lam
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong
| | - Shirley Yin-Yu Pang
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong
| | - Lingfei Li
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong
| | | | - David Boyer Ramsden
- Institute of Metabolism and Systems Research, University of Birmingham, United Kingdom
| | - Shu-Leong Ho
- Division of Neurology, Department of Medicine, University of Hong Kong, Hong Kong
| |
Collapse
|
29
|
Bourdenx M, Daniel J, Genin E, Soria FN, Blanchard-Desce M, Bezard E, Dehay B. Nanoparticles restore lysosomal acidification defects: Implications for Parkinson and other lysosomal-related diseases. Autophagy 2016; 12:472-83. [PMID: 26761717 DOI: 10.1080/15548627.2015.1136769] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Lysosomal impairment causes lysosomal storage disorders (LSD) and is involved in pathogenesis of neurodegenerative diseases, notably Parkinson disease (PD). Strategies enhancing or restoring lysosomal-mediated degradation thus appear as tantalizing disease-modifying therapeutics. Here we demonstrate that poly(DL-lactide-co-glycolide) (PLGA) acidic nanoparticles (aNP) restore impaired lysosomal function in a series of toxin and genetic cellular models of PD, i.e. ATP13A2-mutant or depleted cells or glucocerebrosidase (GBA)-mutant cells, as well as in a genetic model of lysosomal-related myopathy. We show that PLGA-aNP are transported to the lysosome within 24 h, lower lysosomal pH and rescue chloroquine (CQ)-induced toxicity. Re-acidification of defective lysosomes following PLGA-aNP treatment restores lysosomal function in different pathological contexts. Finally, our results show that PLGA-aNP may be detected after intracerebral injection in neurons and attenuate PD-related neurodegeneration in vivo by mechanisms involving a rescue of compromised lysosomes.
Collapse
Affiliation(s)
- Mathieu Bourdenx
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
| | - Jonathan Daniel
- c University de Bordeaux, Institut des Sciences Moléculaires , UMR 5255, Talence , France
| | - Emilie Genin
- c University de Bordeaux, Institut des Sciences Moléculaires , UMR 5255, Talence , France
| | - Federico N Soria
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
| | | | - Erwan Bezard
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
| | - Benjamin Dehay
- a University de Bordeaux, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France.,b CNRS, Institut des Maladies Neurodégénératives , UMR 5293, Bordeaux , France
| |
Collapse
|
30
|
A pipette-based calibration system for fast-scan cyclic voltammetry with fast response times. Biotechniques 2016; 61:269-271. [PMID: 27839513 DOI: 10.2144/000114476] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 09/20/2016] [Indexed: 11/23/2022] Open
Abstract
Fast-scan cyclic voltammetry (FSCV) is an electrochemical technique that utilizes the oxidation and/or reduction of an analyte of interest to infer rapid changes in concentrations. In order to calibrate the resulting oxidative or reductive current, known concentrations of an analyte must be introduced under controlled settings. Here, I describe a simple and cost-effective method, using a Petri dish and pipettes, for the calibration of carbon fiber microelectrodes (CFMs) using FSCV.
Collapse
|
31
|
Wang B, Abraham N, Gao G, Yang Q. Dysregulation of autophagy and mitochondrial function in Parkinson's disease. Transl Neurodegener 2016; 5:19. [PMID: 27822367 PMCID: PMC5087125 DOI: 10.1186/s40035-016-0065-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/17/2016] [Indexed: 01/14/2023] Open
Abstract
Parkinson’s disease (PD) is the second most common neurodegenerative disease. Increasing evidence supports that dysregulation of autophagy and mitochondrial function are closely related with PD pathogenesis. In this review, we briefly summarized autophagy pathway, which consists of macroautophagy, microautophagy and chaperone-mediated autophagy (CMA). Then, we discussed the involvement of mitochondrial dysfunction in PD pathogenesis. We specifically reviewed the recent developments in the relationship among several PD related genes, autophagy and mitochondrial dysfunction, followed by the therapeutic implications of these pathways. In conclusion, we propose that autophagy activity and mitochondrial homeostasis are of high importance in the pathogenesis of PD. Better understanding of these pathways can shed light on the novel therapeutic methods for PD prevention and amelioration.
Collapse
Affiliation(s)
- Bao Wang
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, No. 569 Xinsi Road, Baqiao District, Xi'an, 710038 Shaanxi Province China ; Department of Neurology, Beth Isreal Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, 02215 MA USA
| | - Neeta Abraham
- Department of Neurology, Beth Isreal Deaconess Medical Center, Harvard Medical School, 330 Brookline Ave, Boston, 02215 MA USA
| | - Guodong Gao
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, No. 569 Xinsi Road, Baqiao District, Xi'an, 710038 Shaanxi Province China
| | - Qian Yang
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, No. 569 Xinsi Road, Baqiao District, Xi'an, 710038 Shaanxi Province China
| |
Collapse
|
32
|
Assessing the Mitochondrial Membrane Potential in Cells and In Vivo using Targeted Click Chemistry and Mass Spectrometry. Cell Metab 2016; 23:379-85. [PMID: 26712463 PMCID: PMC4752821 DOI: 10.1016/j.cmet.2015.11.014] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 09/02/2015] [Accepted: 11/15/2015] [Indexed: 01/27/2023]
Abstract
The mitochondrial membrane potential (Δψm) is a major determinant and indicator of cell fate, but it is not possible to assess small changes in Δψm within cells or in vivo. To overcome this, we developed an approach that utilizes two mitochondria-targeted probes each containing a triphenylphosphonium (TPP) lipophilic cation that drives their accumulation in response to Δψm and the plasma membrane potential (Δψp). One probe contains an azido moiety and the other a cyclooctyne, which react together in a concentration-dependent manner by "click" chemistry to form MitoClick. As the mitochondrial accumulation of both probes depends exponentially on Δψm and Δψp, the rate of MitoClick formation is exquisitely sensitive to small changes in these potentials. MitoClick accumulation can then be quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). This approach enables assessment of subtle changes in membrane potentials within cells and in the mouse heart in vivo.
Collapse
|
33
|
Ramsson ES, Cholger D, Dionise A, Poirier N, Andrus A, Curtiss R. Characterization of Fast-Scan Cyclic Voltammetric Electrodes Using Paraffin as an Effective Sealant with In Vitro and In Vivo Applications. PLoS One 2015; 10:e0141340. [PMID: 26505195 PMCID: PMC4623982 DOI: 10.1371/journal.pone.0141340] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/07/2015] [Indexed: 12/21/2022] Open
Abstract
Fast-scan cyclic voltammetry (FSCV) is a powerful technique for measuring sub-second changes in neurotransmitter levels. A great time-limiting factor in the use of FSCV is the production of high-quality recording electrodes; common recording electrodes consist of cylindrical carbon fiber encased in borosilicate glass. When the borosilicate is heated and pulled, the molten glass ideally forms a tight seal around the carbon fiber cylinder. It is often difficult, however, to guarantee a perfect seal between the glass and carbon. Indeed, much of the time spent creating electrodes is in an effort to find a good seal. Even though epoxy resins can be useful in this regard, they are irreversible (seals are permanent), wasteful (epoxy cannot be reused once hardener is added), hazardous (hardeners are often caustic), and require curing. Herein we characterize paraffin as an electrode sealant for FSCV microelectrodes. Paraffin boasts the advantages of near-immediate curing times, simplicity in use, long shelf-life and stable waterproof seals capable of withstanding extended cycling. Borosilicate electrode tips were left intact or broken and dipped in paraffin embedding wax. Excess wax was removed from the carbon surface with xyelenes or by repeated cycling at an extended waveform (-0.4 to 1.4V, 400 V/s, 60 Hz). Then, the waveform was switched to a standard waveform (-0.4 to 1.3V, 400 V/s, 10 Hz) and cycled until stable. Wax-sealing does not inhibit electrode sensitivity, as electrodes detected linear changes in dopamine before and after wax (then xylenes) exposure. Paraffin seals are intact after 11 days of implantation in the mouse, and still capable of measuring transient changes in in vivo dopamine. From this it is clear that paraffin wax is an effective sealant for FSCV electrodes that provides a convenient substitute to epoxy sealants.
Collapse
Affiliation(s)
- Eric S. Ramsson
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Daniel Cholger
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Albert Dionise
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Nicholas Poirier
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Avery Andrus
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| | - Randi Curtiss
- Biomedical Sciences Department, Grand Valley State University, Allendale, MI 49401, United States of America
| |
Collapse
|
34
|
Haddad D, Nakamura K. Understanding the susceptibility of dopamine neurons to mitochondrial stressors in Parkinson's disease. FEBS Lett 2015; 589:3702-13. [PMID: 26526613 DOI: 10.1016/j.febslet.2015.10.021] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/14/2015] [Accepted: 10/15/2015] [Indexed: 12/21/2022]
Abstract
Mitochondria are undoubtedly changed in Parkinson's disease (PD), and mitochondrial functions are disrupted in genetic and pharmacologic models of PD. However, many of these changes might not truly drive neurodegeneration. PD is defined by the particular susceptibility of nigrostriatal dopamine (DA) neurons, but little is understood about the mitochondria in these cells. Here, we critically review the evidence that mitochondrial stressors cause PD. We then consider how changes in the intrinsic function of mitochondria and in their mass, distribution, and dynamics might synergize with an increased need for mitochondria and produce PD, and the importance of understanding how mitochondria contribute to its pathogenesis.
Collapse
Affiliation(s)
- Dominik Haddad
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Ken Nakamura
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Department of Neurology, and Graduate Programs in Neuroscience and Biomedical Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| |
Collapse
|
35
|
Kim HW, Choi WS, Sorscher N, Park HJ, Tronche F, Palmiter RD, Xia Z. Genetic reduction of mitochondrial complex I function does not lead to loss of dopamine neurons in vivo. Neurobiol Aging 2015; 36:2617-27. [PMID: 26070241 DOI: 10.1016/j.neurobiolaging.2015.05.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 12/21/2022]
Abstract
Inhibition of mitochondrial complex I activity is hypothesized to be one of the major mechanisms responsible for dopaminergic neuron death in Parkinson's disease. However, loss of complex I activity by systemic deletion of the Ndufs4 gene, one of the subunits comprising complex I, does not cause dopaminergic neuron death in culture. Here, we generated mice with conditional Ndufs4 knockout in dopaminergic neurons (Ndufs4 conditional knockout mice [cKO]) to examine the effect of complex I inhibition on dopaminergic neuron function and survival during aging and on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in vivo. Ndufs4 cKO mice did not show enhanced dopaminergic neuron loss in the substantia nigra pars compacta or dopamine-dependent motor deficits over the 24-month life span. These mice were just as susceptible to MPTP as control mice. However, compared with control mice, Ndufs4 cKO mice exhibited an age-dependent reduction of dopamine in the striatum and increased α-synuclein phosphorylation in dopaminergic neurons of the substantia nigra pars compacta. We also used an inducible Ndufs4 knockout mouse strain (Ndufs4 inducible knockout) in which Ndufs4 is conditionally deleted in all cells in adult to examine the effect of adult onset, complex I inhibition on MPTP sensitivity of dopaminergic neurons. The Ndufs4 inducible knockout mice exhibited similar sensitivity to MPTP as control littermates. These data suggest that mitochondrial complex I inhibition in dopaminergic neurons does contribute to dopamine loss and the development of α-synuclein pathology. However, it is not sufficient to cause cell-autonomous dopaminergic neuron death during the normal life span of mice. Furthermore, mitochondrial complex I inhibition does not underlie MPTP toxicity in vivo in either cell autonomous or nonautonomous manner. These results provide strong evidence that inhibition of mitochondrial complex I activity is not sufficient to cause dopaminergic neuron death during aging nor does it contribute to dopamine neuron toxicity in the MPTP model of Parkinson's disease. These findings suggest the existence of alternative mechanisms of dopaminergic neuron death independent of mitochondrial complex I inhibition.
Collapse
Affiliation(s)
- Hyung-Wook Kim
- Toxicology Program in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; College of Life Sciences, Sejong University, Seoul, Korea
| | - Won-Seok Choi
- Toxicology Program in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, Gwangju, Korea; College of Medicine, Chonnam National University, Gwangju, Korea
| | - Noah Sorscher
- Graduate Program in Neurobiology & Behavior, University of Washington, Seattle, WA, USA
| | - Hyung Joon Park
- School of Biological Sciences and Technology, College of Natural Sciences, Chonnam National University, Gwangju, Korea; College of Medicine, Chonnam National University, Gwangju, Korea
| | - François Tronche
- Sorbonne Universités, Université Pierre et Marie Curie, UMR_CR18, Neuroscience Paris-Seine, Paris, France; Centre National de la Recherche Scientifique UMR 8246, Paris, France; Institut National de la Santé et de la Rechesrche Médicale U1130, Paris, France
| | - Richard D Palmiter
- Howard Huges Medical Institute, University of Washington, Seattle, WA, USA; Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Zhengui Xia
- Toxicology Program in the Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA; Graduate Program in Neurobiology & Behavior, University of Washington, Seattle, WA, USA.
| |
Collapse
|
36
|
Maertens A, Luechtefeld T, Kleensang A, Hartung T. MPTP's pathway of toxicity indicates central role of transcription factor SP1. Arch Toxicol 2015; 89:743-55. [PMID: 25851821 DOI: 10.1007/s00204-015-1509-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Accepted: 03/16/2015] [Indexed: 01/15/2023]
Abstract
Deriving a Pathway of Toxicity from transcriptomic data remains a challenging task. We explore the use of weighted gene correlation network analysis (WGCNA) to extract an initial network from a small microarray study of MPTP toxicity in mice. Five modules were statistically significant; each module was analyzed for gene signatures in the Chemical and Genetic Perturbation subset of the Molecular Signatures Database as well as for over-represented transcription factor binding sites and WGCNA clustered probes by function and captured pathways relevant to neurodegenerative disorders. The resulting network was analyzed for transcription factor candidates, which were narrowed down via text-mining for relevance to the disease model, and then combined with the large-scale interaction FANTOM4 database to generate a genetic regulatory network. Modules were enriched for transcription factors relevant to Parkinson's disease. Transcription factors significantly improved the number of genes that could be connected in a given component. For each module, the transcription factor that had, by far, the highest number of interactions was SP1, and it also had substantial experimental evidence of interactions. This analysis both captures much of the known biology of MPTP toxicity and suggests several candidates for further study. Furthermore, the analysis strongly suggests that SP1 plays a central role in coordinating the cellular response to MPTP toxicity.
Collapse
Affiliation(s)
- Alexandra Maertens
- Center for Alternatives to Animal Testing, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | | | | | | |
Collapse
|
37
|
Progressive dopaminergic alterations and mitochondrial abnormalities in LRRK2 G2019S knock-in mice. Neurobiol Dis 2015; 78:172-95. [PMID: 25836420 DOI: 10.1016/j.nbd.2015.02.031] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 02/19/2015] [Accepted: 02/21/2015] [Indexed: 01/19/2023] Open
Abstract
Mutations in the LRRK2 gene represent the most common genetic cause of late onset Parkinson's disease. The physiological and pathological roles of LRRK2 are yet to be fully determined but evidence points towards LRRK2 mutations causing a gain in kinase function, impacting on neuronal maintenance, vesicular dynamics and neurotransmitter release. To explore the role of physiological levels of mutant LRRK2, we created knock-in (KI) mice harboring the most common LRRK2 mutation G2019S in their own genome. We have performed comprehensive dopaminergic, behavioral and neuropathological analyses in this model up to 24months of age. We find elevated kinase activity in the brain of both heterozygous and homozygous mice. Although normal at 6months, by 12months of age, basal and pharmacologically induced extracellular release of dopamine is impaired in both heterozygous and homozygous mice, corroborating previous findings in transgenic models over-expressing mutant LRRK2. Via in vivo microdialysis measurement of basal and drug-evoked extracellular release of dopamine and its metabolites, our findings indicate that exocytotic release from the vesicular pool is impaired. Furthermore, profound mitochondrial abnormalities are evident in the striatum of older homozygous G2019S KI mice, which are consistent with mitochondrial fission arrest. We anticipate that this G2019S mouse line will be a useful pre-clinical model for further evaluation of early mechanistic events in LRRK2 pathogenesis and for second-hit approaches to model disease progression.
Collapse
|
38
|
Torraco A, Peralta S, Iommarini L, Diaz F. Mitochondrial Diseases Part I: mouse models of OXPHOS deficiencies caused by defects in respiratory complex subunits or assembly factors. Mitochondrion 2015; 21:76-91. [PMID: 25660179 DOI: 10.1016/j.mito.2015.01.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 11/22/2014] [Accepted: 01/05/2015] [Indexed: 10/24/2022]
Abstract
Mitochondrial disorders are the most common inborn errors of metabolism affecting the oxidative phosphorylation system (OXPHOS). Because of the poor knowledge of the pathogenic mechanisms, a cure for these disorders is still unavailable and all the treatments currently in use are supportive more than curative. Therefore, in the past decade a great variety of mouse models have been developed to assess the in vivo function of several mitochondrial proteins involved in human diseases. Due to the genetic and physiological similarity to humans, mice represent reliable models to study the pathogenic mechanisms of mitochondrial disorders and are precious to test new therapeutic approaches. Here we summarize the features of several mouse models of mitochondrial diseases directly related to defects in subunits of the OXPHOS complexes or in assembly factors. We discuss how these models recapitulate many human conditions and how they have contributed to the understanding of mitochondrial function in health and disease.
Collapse
Affiliation(s)
- Alessandra Torraco
- Unit for Neuromuscular and Neurodegenerative Disorders, Laboratory of Molecular Medicine, Bambino Gesù Children's Hospital, IRCCS, Viale di San Paolo, 15-00146 Rome, Italy.
| | - Susana Peralta
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology (FABIT), University of Bologna, Via Irnerio 42, 40126 Bologna, Italy.
| | - Francisca Diaz
- Department of Neurology, University of Miami, Miller School of Medicine, Miami, FL 33136, USA.
| |
Collapse
|
39
|
Segura-Aguilar J, Kostrzewa RM. Neurotoxin mechanisms and processes relevant to Parkinson's disease: an update. Neurotox Res 2015; 27:328-54. [PMID: 25631236 DOI: 10.1007/s12640-015-9519-y] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 01/13/2015] [Accepted: 01/13/2015] [Indexed: 12/14/2022]
Abstract
The molecular mechanism responsible for degenerative process in the nigrostriatal dopaminergic system in Parkinson's disease (PD) remains unknown. One major advance in this field has been the discovery of several genes associated to familial PD, including alpha synuclein, parkin, LRRK2, etc., thereby providing important insight toward basic research approaches. There is an consensus in neurodegenerative research that mitochon dria dysfunction, protein degradation dysfunction, aggregation of alpha synuclein to neurotoxic oligomers, oxidative and endoplasmic reticulum stress, and neuroinflammation are involved in degeneration of the neuromelanin-containing dopaminergic neurons that are lost in the disease. An update of the mechanisms relating to neurotoxins that are used to produce preclinical models of Parkinson´s disease is presented. 6-Hydroxydopamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and rotenone have been the most wisely used neurotoxins to delve into mechanisms involved in the loss of dopaminergic neurons containing neuromelanin. Neurotoxins generated from dopamine oxidation during neuromelanin formation are likewise reviewed, as this pathway replicates neurotoxin-induced cellular oxidative stress, inactivation of key proteins related to mitochondria and protein degradation dysfunction, and formation of neurotoxic aggregates of alpha synuclein. This survey of neurotoxin modeling-highlighting newer technologies and implicating a variety of processes and pathways related to mechanisms attending PD-is focused on research studies from 2012 to 2014.
Collapse
Affiliation(s)
- Juan Segura-Aguilar
- Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Independencia 1027, Casilla, 70000, Santiago 7, Chile,
| | | |
Collapse
|
40
|
The respiratory chain supercomplex organization is independent of COX7a2l isoforms. Cell Metab 2014; 20:1069-75. [PMID: 25470551 PMCID: PMC4261080 DOI: 10.1016/j.cmet.2014.11.005] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/25/2014] [Accepted: 11/05/2014] [Indexed: 01/09/2023]
Abstract
The organization of individual respiratory chain complexes into supercomplexes or respirasomes has attracted great interest because of the implications for cellular energy conversion. Recently, it was reported that commonly used mouse strains harbor a short COX7a2l (SCAFI) gene isoform that supposedly precludes the formation of complex IV-containing supercomplexes. This claim potentially has serious implications for numerous mouse studies addressing important topics in metabolism, including adaptation to space flights. Using several complementary experimental approaches, we show that mice with the short COX7a2l isoform have normal biogenesis and steady-state levels of complex IV-containing supercomplexes and consequently have normal respiratory chain function. Furthermore, we use a mouse knockout of Lrpprc and show that loss of complex IV compromises respirasome formation. We conclude that the presence of the short COX7a2l isoform in the commonly used C57BL/6 mouse strains does not prevent their use in metabolism research.
Collapse
|
41
|
Song L, Cortopassi G. Mitochondrial complex I defects increase ubiquitin in substantia nigra. Brain Res 2014; 1594:82-91. [PMID: 25446449 DOI: 10.1016/j.brainres.2014.11.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 10/16/2014] [Accepted: 11/07/2014] [Indexed: 11/18/2022]
Abstract
Parkinson׳s disease (PD) is the second most common neurodegenerative disorder in the developed world, and is characterized by the loss of dopaminergic (DA) neurons in the substantia nigra (SN) of midbrain. Mitochondrial complex I dysfunction has been implicated in PD pathophysiology, yet the molecular mechanism by which complex I defects may cause DA neurodegeneration remain unclear. Using Ndufs4 mouse model of mitochondrial complex I deficiency, we observed a remarkable ubiquitin protein increase in SN of Ndufs4-/- (KO) mice. By contrast, neurofilaments were significantly decreased in SN of KO mice. Furthermore, mass spectrometry and co-immunoprecipitation (Co-IP) analysis indicated an increase in ubiquitinated neurofilaments in midbrain of KO mice, whereas 20S proteasome activities were decreased, which could potentially explain the buildup of ubiquitin protein. Collectively, these data suggest that mitochondrial complex I defects cause proteasome inhibition, a consequent increase in ubiquitinated neurofilaments and other proteins, and decrease the expression of neurofilaments that could be relevant to the mechanism of DA neuronal death in PD.
Collapse
Affiliation(s)
- Lanying Song
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA
| | - Gino Cortopassi
- Department of Molecular Biosciences, University of California, Davis, CA 95616, USA.
| |
Collapse
|
42
|
Camilleri A, Vassallo N. The centrality of mitochondria in the pathogenesis and treatment of Parkinson's disease. CNS Neurosci Ther 2014; 20:591-602. [PMID: 24703487 DOI: 10.1111/cns.12264] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 03/07/2014] [Accepted: 03/08/2014] [Indexed: 12/14/2022] Open
Abstract
Parkinson's disease (PD) is an incurable neurodegenerative disorder leading to progressive motor impairment and for which there is no cure. From the first postmortem account describing a lack of mitochondrial complex I in the substantia nigra of PD sufferers, the direct association between mitochondrial dysfunction and death of dopaminergic neurons has ever since been consistently corroborated. In this review, we outline common pathways shared by both sporadic and familial PD that remarkably and consistently converge at the level of mitochondrial integrity. Furthermore, such knowledge has incontrovertibly established mitochondria as a valid therapeutic target in neurodegeneration. We discuss several mitochondria-directed therapies that promote the preservation, rescue, or restoration of dopaminergic neurons and which have been identified in the laboratory and in preclinical studies. Some of these have progressed to clinical trials, albeit the identification of an unequivocal disease-modifying neurotherapeutic is still elusive. The challenge is therefore to improve further, not least by more research on the molecular mechanisms and pathophysiological consequences of mitochondrial dysfunction in PD.
Collapse
Affiliation(s)
- Angelique Camilleri
- Department of Physiology and Biochemistry, University of Malta, Msida 2080, Malta
| | | |
Collapse
|
43
|
Chouchani ET, Methner C, Buonincontri G, Hu CH, Logan A, Sawiak SJ, Murphy MP, Krieg T. Complex I deficiency due to selective loss of Ndufs4 in the mouse heart results in severe hypertrophic cardiomyopathy. PLoS One 2014; 9:e94157. [PMID: 24705922 PMCID: PMC3976382 DOI: 10.1371/journal.pone.0094157] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 03/11/2014] [Indexed: 01/07/2023] Open
Abstract
Mitochondrial complex I, the primary entry point for electrons into the mitochondrial respiratory chain, is both critical for aerobic respiration and a major source of reactive oxygen species. In the heart, chronic dysfunction driving cardiomyopathy is frequently associated with decreased complex I activity, from both genetic and environmental causes. To examine the functional relationship between complex I disruption and cardiac dysfunction we used an established mouse model of mild and chronic complex I inhibition through heart-specific Ndufs4 gene ablation. Heart-specific Ndufs4-null mice had a decrease of ∼50% in complex I activity within the heart, and developed severe hypertrophic cardiomyopathy as assessed by magnetic resonance imaging. The decrease in complex I activity, and associated cardiac dysfunction, occurred absent an increase in mitochondrial hydrogen peroxide levels in vivo, accumulation of markers of oxidative damage, induction of apoptosis, or tissue fibrosis. Taken together, these results indicate that diminished complex I activity in the heart alone is sufficient to drive hypertrophic cardiomyopathy independently of alterations in levels of mitochondrial hydrogen peroxide or oxidative damage.
Collapse
Affiliation(s)
- Edward T. Chouchani
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- MRC Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Carmen Methner
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Chou-Hui Hu
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Angela Logan
- MRC Mitochondrial Biology Unit, Cambridge, United Kingdom
| | - Stephen J. Sawiak
- Wolfson Brain Imaging Centre, University of Cambridge, United Kingdom
| | | | - Thomas Krieg
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
- * E-mail:
| |
Collapse
|
44
|
Gaweda-Walerych K, Zekanowski C. The impact of mitochondrial DNA and nuclear genes related to mitochondrial functioning on the risk of Parkinson's disease. Curr Genomics 2014; 14:543-59. [PMID: 24532986 PMCID: PMC3924249 DOI: 10.2174/1389202914666131210211033] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/30/2013] [Accepted: 08/29/2013] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial dysfunction and oxidative stress are the major factors implicated in Parkinson’s disease (PD)
pathogenesis. The maintenance of healthy mitochondria is a very complex process coordinated bi-genomically. Here, we
review association studies on mitochondrial haplogroups and subhaplogroups, discussing the underlying molecular
mechanisms. We also focus on variation in the nuclear genes (NDUFV2, PGC-1alpha, HSPA9, LRPPRC, MTIF3,
POLG1, and TFAM encoding NADH dehydrogenase (ubiquinone) flavoprotein 2, peroxisome proliferator-activated receptor
gamma coactivator 1-alpha, mortalin, leucine-rich pentatricopeptide repeat containing protein, translation initiation
factor 3, mitochondrial DNA polymerase gamma, and mitochondrial transcription factor A, respectively) primarily linked
to regulation of mitochondrial functioning that recently have been associated with PD risk. Possible interactions between
mitochondrial and nuclear genetic variants and related proteins are discussed.
Collapse
Affiliation(s)
- Katarzyna Gaweda-Walerych
- Laboratory of Neurogenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5 str., 02-106 Warszawa, Poland
| | - Cezary Zekanowski
- Laboratory of Neurogenetics, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5 str., 02-106 Warszawa, Poland
| |
Collapse
|
45
|
Gu F, Chauhan V, Kaur K, Brown WT, LaFauci G, Wegiel J, Chauhan A. Alterations in mitochondrial DNA copy number and the activities of electron transport chain complexes and pyruvate dehydrogenase in the frontal cortex from subjects with autism. Transl Psychiatry 2013; 3:e299. [PMID: 24002085 PMCID: PMC3784762 DOI: 10.1038/tp.2013.68] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 07/17/2013] [Accepted: 07/19/2013] [Indexed: 12/13/2022] Open
Abstract
Autism is a neurodevelopmental disorder associated with social deficits and behavioral abnormalities. Recent evidence suggests that mitochondrial dysfunction and oxidative stress may contribute to the etiology of autism. This is the first study to compare the activities of mitochondrial electron transport chain (ETC) complexes (I-V) and pyruvate dehydrogenase (PDH), as well as mitochondrial DNA (mtDNA) copy number in the frontal cortex tissues from autistic and age-matched control subjects. The activities of complexes I, V and PDH were most affected in autism (n=14) being significantly reduced by 31%, 36% and 35%, respectively. When 99% confidence interval (CI) of control group was taken as a reference range, impaired activities of complexes I, III and V were observed in 43%, 29% and 43% of autistic subjects, respectively. Reduced activities of all five ETC complexes were observed in 14% of autistic cases, and the activities of multiple complexes were decreased in 29% of autistic subjects. These results suggest that defects in complexes I and III (sites of mitochondrial free radical generation) and complex V (adenosine triphosphate synthase) are more prevalent in autism. PDH activity was also reduced in 57% of autistic subjects. The ratios of mtDNA of three mitochondrial genes ND1, ND4 and Cyt B (that encode for subunits of complexes I and III) to nuclear DNA were significantly increased in autism, suggesting a higher mtDNA copy number in autism. Compared with the 95% CI of the control group, 44% of autistic children showed higher copy numbers of all three mitochondrial genes examined. Furthermore, ND4 and Cyt B deletions were observed in 44% and 33% of autistic children, respectively. This study indicates that autism is associated with mitochondrial dysfunction in the brain.
Collapse
Affiliation(s)
- F Gu
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - V Chauhan
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - K Kaur
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - W T Brown
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - G LaFauci
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - J Wegiel
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| | - A Chauhan
- NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY, USA
| |
Collapse
|
46
|
Sanders LH, Timothy Greenamyre J. Oxidative damage to macromolecules in human Parkinson disease and the rotenone model. Free Radic Biol Med 2013; 62:111-120. [PMID: 23328732 PMCID: PMC3677955 DOI: 10.1016/j.freeradbiomed.2013.01.003] [Citation(s) in RCA: 416] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 01/08/2013] [Accepted: 01/08/2013] [Indexed: 11/25/2022]
Abstract
Parkinson disease (PD), the most common neurodegenerative movement disorder, is associated with selective degeneration of nigrostriatal dopamine neurons. Although the underlying mechanisms contributing to neurodegeneration in PD seem to be multifactorial, mitochondrial impairment and oxidative stress are widely considered to be central to many forms of the disease. Whether oxidative stress is a cause or a consequence of dopaminergic death, there is substantial evidence for oxidative stress both in human PD patients and in animal models of PD, especially using rotenone, a complex I inhibitor. There are many indices of oxidative stress, but this review covers the recent evidence for oxidative damage to nucleic acids, lipids, and proteins in both the brain and the peripheral tissues in human PD and in the rotenone model. Limitations of the existing literature and future perspectives are discussed. Understanding how each particular macromolecule is damaged by oxidative stress and the interplay of secondary damage to other biomolecules may help us design better targets for the treatment of PD.
Collapse
Affiliation(s)
- Laurie H Sanders
- Pittsburgh Institute for Neurodegenerative Diseases, Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - J Timothy Greenamyre
- Pittsburgh Institute for Neurodegenerative Diseases, Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| |
Collapse
|
47
|
Rolland SG, Motori E, Memar N, Hench J, Frank S, Winklhofer KF, Conradt B. Impaired complex IV activity in response to loss of LRPPRC function can be compensated by mitochondrial hyperfusion. Proc Natl Acad Sci U S A 2013; 110:E2967-76. [PMID: 23878239 PMCID: PMC3740885 DOI: 10.1073/pnas.1303872110] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mitochondrial morphology changes in response to various stimuli but the significance of this is unclear. In a screen for mutants with abnormal mitochondrial morphology, we identified MMA-1, the Caenorhabditis elegans homolog of the French Canadian Leigh Syndrome protein LRPPRC (leucine-rich pentatricopeptide repeat containing). We demonstrate that reducing mma-1 or LRPPRC function causes mitochondrial hyperfusion. Reducing mma-1/LRPPRC function also decreases the activity of complex IV of the electron transport chain, however without affecting cellular ATP levels. Preventing mitochondrial hyperfusion in mma-1 animals causes larval arrest and embryonic lethality. Furthermore, prolonged LRPPRC knock-down in mammalian cells leads to mitochondrial fragmentation and decreased levels of ATP. These findings indicate that in a mma-1/LRPPRC-deficient background, hyperfusion allows mitochondria to maintain their functions despite a reduction in complex IV activity. Our data reveal an evolutionary conserved mechanism that is triggered by reduced complex IV function and that induces mitochondrial hyperfusion to transiently compensate for a drop in the activity of the electron transport chain.
Collapse
Affiliation(s)
- Stéphane G. Rolland
- Department Biology II, Center for Integrated Protein Science, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Elisa Motori
- Department of Neurobiochemistry, Adolf Butenandt Institute, Ludwig-Maximilians-University, 80336 Munich, Germany
- Department of Life Quality Studies–Alma Mater Studiorum, University of Bologna, 40126 Bologna, Italy
| | - Nadin Memar
- Department Biology II, Center for Integrated Protein Science, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Jürgen Hench
- Department of Neuropathology, Institute for Pathology, University Hospitals Basel, CH-4031 Basel, Switzerland
| | - Stephan Frank
- Department of Neuropathology, Institute for Pathology, University Hospitals Basel, CH-4031 Basel, Switzerland
| | - Konstanze F. Winklhofer
- Department of Neurobiochemistry, Adolf Butenandt Institute, Ludwig-Maximilians-University, 80336 Munich, Germany
- German Center for Neurodegenerative Diseases, 80336 Munich, Germany
- Munich Cluster for Systems Neurology, 80336 Munich, Germany; and
- Department of Molecular Cell Biology, Institute of Physiological Chemistry, Ruhr University Bochum, 44801 Bochum, Germany
| | - Barbara Conradt
- Department Biology II, Center for Integrated Protein Science, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| |
Collapse
|
48
|
Karamanlidis G, Lee CF, Garcia-Menendez L, Kolwicz SC, Suthammarak W, Gong G, Sedensky MM, Morgan PG, Wang W, Tian R. Mitochondrial complex I deficiency increases protein acetylation and accelerates heart failure. Cell Metab 2013; 18:239-50. [PMID: 23931755 PMCID: PMC3779647 DOI: 10.1016/j.cmet.2013.07.002] [Citation(s) in RCA: 338] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 03/22/2013] [Accepted: 07/02/2013] [Indexed: 01/04/2023]
Abstract
Mitochondrial respiratory dysfunction is linked to the pathogenesis of multiple diseases, including heart failure, but the specific mechanisms for this link remain largely elusive. We modeled the impairment of mitochondrial respiration by the inactivation of the Ndufs4 gene, a protein critical for complex I assembly, in the mouse heart (cKO). Although complex I-supported respiration decreased by >40%, the cKO mice maintained normal cardiac function in vivo and high-energy phosphate content in isolated perfused hearts. However, the cKO mice developed accelerated heart failure after pressure overload or repeated pregnancy. Decreased NAD(+)/NADH ratio by complex I deficiency inhibited Sirt3 activity, leading to an increase in protein acetylation and sensitization of the permeability transition in mitochondria (mPTP). NAD(+) precursor supplementation to cKO mice partially normalized the NAD(+)/NADH ratio, protein acetylation, and mPTP sensitivity. These findings describe a mechanism connecting mitochondrial dysfunction to the susceptibility to diseases and propose a potential therapeutic target.
Collapse
Affiliation(s)
- Georgios Karamanlidis
- Mitochondria and Metabolism Center, Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, 98109, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
49
|
Subramaniam SR, Chesselet MF. Mitochondrial dysfunction and oxidative stress in Parkinson's disease. Prog Neurobiol 2013; 106-107:17-32. [PMID: 23643800 PMCID: PMC3742021 DOI: 10.1016/j.pneurobio.2013.04.004] [Citation(s) in RCA: 505] [Impact Index Per Article: 45.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 04/13/2013] [Accepted: 04/22/2013] [Indexed: 12/12/2022]
Abstract
Parkinson's disease (PD) is a movement disorder that is characterized by the progressive degeneration of dopaminergic neurons in substantia nigra pars compacta resulting in dopamine deficiency in the striatum. Although majority of the PD cases are sporadic several genetic mutations have also been linked to the disease thus providing new opportunities to study the pathology of the illness. Studies in humans and various animal models of PD reveal that mitochondrial dysfunction might be a defect that occurs early in PD pathogenesis and appears to be a widespread feature in both sporadic and monogenic forms of PD. The general mitochondrial abnormalities linked with the disease include mitochondrial electron transport chain impairment, alterations in mitochondrial morphology and dynamics, mitochondrial DNA mutations and anomaly in calcium homeostasis. Mitochondria are vital organelles with multiple functions and their dysfunction can lead to a decline in energy production, generation of reactive oxygen species and induction of stress-induced apoptosis. In this review, we give an outline of mitochondrial functions that are affected in the pathogenesis of sporadic and familial PD, and hence provide insights that might be valuable for focused future research to exploit possible mitochondrial targets for neuroprotective interventions in PD.
Collapse
Affiliation(s)
- Sudhakar Raja Subramaniam
- Department of Neurology, David Geffen School of Medicine, UCLA, 710 Westwood Plaza, Los Angeles, CA 90095-1769, USA
| | | |
Collapse
|
50
|
Terzioglu M, Ruzzenente B, Harmel J, Mourier A, Jemt E, López MD, Kukat C, Stewart JB, Wibom R, Meharg C, Habermann B, Falkenberg M, Gustafsson CM, Park CB, Larsson NG. MTERF1 binds mtDNA to prevent transcriptional interference at the light-strand promoter but is dispensable for rRNA gene transcription regulation. Cell Metab 2013; 17:618-26. [PMID: 23562081 DOI: 10.1016/j.cmet.2013.03.006] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 01/22/2013] [Accepted: 03/12/2013] [Indexed: 11/30/2022]
Abstract
Mitochondrial transcription termination factor 1, MTERF1, has been reported to couple rRNA gene transcription initiation with termination and is therefore thought to be a key regulator of mammalian mitochondrial ribosome biogenesis. The prevailing model is based on a series of observations published over the last two decades, but no in vivo evidence exists to show that MTERF1 regulates transcription of the heavy-strand region of mtDNA containing the rRNA genes. Here, we demonstrate that knockout of Mterf1 in mice has no effect on mitochondrial rRNA levels or mitochondrial translation. Instead, loss of Mterf1 influences transcription initiation at the light-strand promoter, resulting in a decrease of de novo transcription manifested as reduced 7S RNA levels. Based on these observations, we suggest that MTERF1 does not regulate heavy-strand transcription, but rather acts to block transcription on the opposite strand of mtDNA to prevent transcription interference at the light-strand promoter.
Collapse
Affiliation(s)
- Mügen Terzioglu
- Department of Mitochondrial Biology, Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|