1
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Nithianandam V, Sarkar S, Feany MB. Pathways controlling neurotoxicity and proteostasis in mitochondrial complex I deficiency. Hum Mol Genet 2024; 33:860-871. [PMID: 38324746 PMCID: PMC11070137 DOI: 10.1093/hmg/ddae018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 01/02/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024] Open
Abstract
Neuromuscular disorders caused by dysfunction of the mitochondrial respiratory chain are common, severe and untreatable. We recovered a number of mitochondrial genes, including electron transport chain components, in a large forward genetic screen for mutations causing age-related neurodegeneration in the context of proteostasis dysfunction. We created a model of complex I deficiency in the Drosophila retina to probe the role of protein degradation abnormalities in mitochondrial encephalomyopathies. Using our genetic model, we found that complex I deficiency regulates both the ubiquitin/proteasome and autophagy/lysosome arms of the proteostasis machinery. We further performed an in vivo kinome screen to uncover new and potentially druggable mechanisms contributing to complex I related neurodegeneration and proteostasis failure. Reduction of RIOK kinases and the innate immune signaling kinase pelle prevented neurodegeneration in complex I deficiency animals. Genetically targeting oxidative stress, but not RIOK1 or pelle knockdown, normalized proteostasis markers. Our findings outline distinct pathways controlling neurodegeneration and protein degradation in complex I deficiency and introduce an experimentally facile model in which to study these debilitating and currently treatment-refractory disorders.
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Affiliation(s)
- Vanitha Nithianandam
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, United States
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, 5425 Wisconsin Avenue, Chevy Chase, MD 20815, United States
| | - Souvarish Sarkar
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, United States
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, 5425 Wisconsin Avenue, Chevy Chase, MD 20815, United States
| | - Mel B Feany
- Department of Pathology, Brigham and Women’s Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, United States
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, 5425 Wisconsin Avenue, Chevy Chase, MD 20815, United States
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2
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Ohtsuka H, Shimasaki T, Aiba H. Low-Molecular Weight Compounds that Extend the Chronological Lifespan of Yeasts, Saccharomyces cerevisiae, and Schizosaccharomyces pombe. Adv Biol (Weinh) 2024; 8:e2400138. [PMID: 38616173 DOI: 10.1002/adbi.202400138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/04/2024] [Indexed: 04/16/2024]
Abstract
Yeast is an excellent model organism for research for regulating aging and lifespan, and the studies have made many contributions to date, including identifying various factors and signaling pathways related to aging and lifespan. More than 20 years have passed since molecular biological perspectives are adopted in this research field, and intracellular factors and signal pathways that control aging and lifespan have evolutionarily conserved from yeast to mammals. Furthermore, these findings have been applied to control the aging and lifespan of various model organisms by adjustment of the nutritional environment, genetic manipulation, and drug treatment using low-molecular weight compounds. Among these, drug treatment is easier than the other methods, and research into drugs that regulate aging and lifespan is consequently expected to become more active. Chronological lifespan, a definition of yeast lifespan, refers to the survival period of a cell population under nondividing conditions. Herein, low-molecular weight compounds are summarized that extend the chronological lifespan of Saccharomyces cerevisiae and Schizosaccharomyces pombe, along with their intracellular functions. The low-molecular weight compounds are also discussed that extend the lifespan of other model organisms. Compounds that have so far only been studied in yeast may soon extend lifespan in other organisms.
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Affiliation(s)
- Hokuto Ohtsuka
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, Japan
| | - Takafumi Shimasaki
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, Japan
| | - Hirofumi Aiba
- Laboratory of Molecular Microbiology, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, Japan
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3
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Thyne KM, Camones R, Salmon AB. Sulfur Amino Acid Restriction alters mitochondrial function depending on tissue, sex, and Methionine sulfoxide reductase A (MsrA) status. RESEARCH SQUARE 2023:rs.3.rs-3755231. [PMID: 38196647 PMCID: PMC10775364 DOI: 10.21203/rs.3.rs-3755231/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Methionine restriction (MR) has been shown to affect mitochondrial function including altering oxygen consumption, reactive oxygen species (ROS) generation, Complex expression, and oxidative damage. The sulfur-containing amino acid methionine can become oxidized forming methionine sulfoxide which can lead to changes in protein function and signaling. Methionine sulfoxide reductases are endogenous enzymes capable of reducing methionine sulfoxide, with Methionine sulfoxide reductase A (MsrA) being ubiquitously expressed in mammals. Here we investigated if the effects of MR on mitochondrial function required functional MsrA in the liver and kidney which are the major tissues involved in sulfur biochemistry and both highly express MsrA. Moreover, MsrA is endogenously found in the mitochondria thereby providing potential mechanisms linking diet to mitochondrial phenotype. We found sex-specific changes in oxygen consumption of isolated mitochondria and females showed changes with MR in a tissue-dependent manner - increased in liver and decreased in kidney. Loss of MsrA increased or decreased oxygen consumption depending on the tissue and which portion of the electron transport chain was being tested. In general, males had few changes in either tissue regardless of MR or MsrA status. Hydrogen peroxide production was increased in the kidney with MR regardless of sex or MsrA status. However, in the liver, production was increased by MR in females and only slightly higher with loss of MsrA in both sexes. Mitochondrial Complex expression was found to be largely unchanged in either tissue suggesting these effects are driven by regulatory mechanisms and not by changes in expression. Together these results suggest that sex and MsrA status do impact the mitochondrial effects of MR in a tissue-specific manner.
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Affiliation(s)
- Kevin M Thyne
- The University of Texas Health Science Center at San Antonio
| | - Raechel Camones
- The University of Texas Health Science Center at San Antonio
| | - Adam B Salmon
- The University of Texas Health Science Center at San Antonio
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4
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Bene M, Salmon AB. Testing the evidence that lifespan-extending compound interventions are conserved across laboratory animal model species. GeroScience 2023; 45:1401-1409. [PMID: 36637786 PMCID: PMC10400519 DOI: 10.1007/s11357-022-00722-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/29/2022] [Indexed: 01/14/2023] Open
Abstract
A growing number of pharmaceutical and small molecule interventions are reported to extend the lifespan of laboratory animals including Caenorhabditis, Drosophila, and mouse. However, the degree to which these pro-longevity interventions are conserved across species is unclear. Here, we took two approaches to ask the question: to what extent do longevity intervention studies in Caenorhabditis and Drosophila recapitulate effects on mouse lifespan? The first approach analyzes all published reports on longevity in the literature collated by the DrugAge database, and the second approach focused on results designed for reproducibility as reported from the NIA-supported Interventions Testing Program (ITP) and the Caenorhabditis Interventions Testing Program (CITP). Using published data sources, we identify only modest sensitivity and specificity of Drosophila interventional studies for identifying pro-longevity compounds in mouse lifespan studies. Surprisingly, reported studies in C. elegans show little predictive value for identifying drugs that extend lifespan in mice. The results therefore suggest caution should be used when making assumptions about the translatability of lifespan-extending compounds across species, including human intervention.
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Affiliation(s)
- Michael Bene
- Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA
| | - Adam B Salmon
- Sam and Ann Barshop Institute for Longevity and Aging Studies, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA.
- Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, Texas, 78229, USA.
- Geriatric Research Education and Clinical Center, Audie L. Murphy Hospital, South Texas Veterans Health Care System, San Antonio, Texas, 78229, USA.
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5
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Szlachcic E, Dańko MJ, Czarnoleski M. Rapamycin supplementation of Drosophila melanogaster larvae results in less viable adults with smaller cells. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230080. [PMID: 37351490 PMCID: PMC10282583 DOI: 10.1098/rsos.230080] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 05/30/2023] [Indexed: 06/24/2023]
Abstract
The intrinsic sources of mortality relate to the ability to meet the metabolic demands of tissue maintenance and repair, ultimately shaping ageing patterns. Anti-ageing mechanisms compete for resources with other functions, including those involved in maintaining functional plasma membranes. Consequently, organisms with smaller cells and more plasma membranes should devote more resources to membrane maintenance, leading to accelerated intrinsic mortality and ageing. To investigate this unexplored trade-off, we reared Drosophila melanogaster larvae on food with or without rapamycin (a TOR pathway inhibitor) to produce small- and large-celled adult flies, respectively, and measured their mortality rates. Males showed higher mortality than females. As expected, small-celled flies (rapamycin) showed higher mortality than their large-celled counterparts (control), but only in early adulthood. Contrary to predictions, the median lifespan was similar between the groups. Rapamycin administered to adults prolongs life; thus, the known direct physiological effects of rapamycin cannot explain our results. Instead, we invoke indirect effects of rapamycin, manifested as reduced cell size, as a driver of increased early mortality. We conclude that cell size differences between organisms and the associated burdens of plasma membrane maintenance costs may be important but overlooked factors influencing mortality patterns in nature.
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Affiliation(s)
- Ewa Szlachcic
- Life History Evolution Group, Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Kraków, Poland
| | - Maciej J. Dańko
- Max Planck Institute for Demographic Research, Rostock, Germany
| | - Marcin Czarnoleski
- Life History Evolution Group, Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Kraków, Poland
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6
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Viscomi C, Zeviani M. Experimental therapy for mitochondrial diseases. HANDBOOK OF CLINICAL NEUROLOGY 2023; 194:259-277. [PMID: 36813318 DOI: 10.1016/b978-0-12-821751-1.00013-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
Mitochondrial diseases are extremely heterogeneous genetic disorders due to faulty oxidative phosphorylation (OxPhos). No cure is currently available for these conditions, beside supportive interventions aimed at relieving complications. Mitochondria are under a double genetic control carried out by the mitochondrial DNA (mtDNA) and by nuclear DNA. Thus, not surprisingly, mutations in either genome can cause mitochondrial disease. Although mitochondria are usually associated with respiration and ATP synthesis, they play fundamental roles in a large number of other biochemical, signaling, and execution pathways, each being a potential target for therapeutic interventions. These can be classified as general therapies, i.e., potentially applicable to a number of different mitochondrial conditions, or therapies tailored to a single disease, i.e., personalized approaches, such as gene therapy, cell therapy, and organ replacement. Mitochondrial medicine is a particularly lively research field, and the last few years witnessed a steady increase in the number of clinical applications. This chapter will present the most recent therapeutic attempts emerged from preclinical work and an update of the currently ongoing clinical applications. We think that we are starting a new era in which the etiologic treatment of these conditions is becoming a realistic option.
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Affiliation(s)
- Carlo Viscomi
- Department of Biomedical Sciences, University of Padova, Padova, Italy.
| | - Massimo Zeviani
- Department of Neurosciences, University of Padova, Padova, Italy; Venetian Institute of Molecular Medicine, Padova, Italy.
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7
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Bennett CF, Ronayne CT, Puigserver P. Targeting adaptive cellular responses to mitochondrial bioenergetic deficiencies in human disease. FEBS J 2022; 289:6969-6993. [PMID: 34510753 PMCID: PMC8917243 DOI: 10.1111/febs.16195] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/25/2021] [Accepted: 09/10/2021] [Indexed: 01/13/2023]
Abstract
Mitochondrial dysfunction is increasingly appreciated as a central contributor to human disease. Oxidative metabolism at the mitochondrial respiratory chain produces ATP and is intricately tied to redox homeostasis and biosynthetic pathways. Metabolic stress arising from genetic mutations in mitochondrial genes and environmental factors such as malnutrition or overnutrition is perceived by the cell and leads to adaptive and maladaptive responses that can underlie pathology. Here, we will outline cellular sensors that react to alterations in energy production, organellar redox, and metabolites stemming from mitochondrial disease (MD) mutations. MD is a heterogeneous group of disorders primarily defined by defects in mitochondrial oxidative phosphorylation from nuclear or mitochondrial-encoded gene mutations. Preclinical therapies that improve fitness of MD mouse models have been recently identified. Targeting metabolic/energetic deficiencies, maladaptive signaling processes, and hyper-oxygenation of tissues are all strategies aside from direct genetic approaches that hold therapeutic promise. A further mechanistic understanding of these curative processes as well as the identification of novel targets will significantly impact mitochondrial biology and disease research.
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Affiliation(s)
- Christopher F Bennett
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Conor T Ronayne
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Pere Puigserver
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
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8
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Blagosklonny MV. Rapamycin treatment early in life reprograms aging: hyperfunction theory and clinical practice. Aging (Albany NY) 2022; 14:8140-8149. [DOI: 10.18632/aging.204354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 10/20/2022] [Indexed: 11/25/2022]
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9
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Green A, Hossain T, Eckmann DM. Mitochondrial dynamics involves molecular and mechanical events in motility, fusion and fission. Front Cell Dev Biol 2022; 10:1010232. [PMID: 36340034 PMCID: PMC9626967 DOI: 10.3389/fcell.2022.1010232] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/06/2022] [Indexed: 11/13/2022] Open
Abstract
Mitochondria are cell organelles that play pivotal roles in maintaining cell survival, cellular metabolic homeostasis, and cell death. Mitochondria are highly dynamic entities which undergo fusion and fission, and have been shown to be very motile in vivo in neurons and in vitro in multiple cell lines. Fusion and fission are essential for maintaining mitochondrial homeostasis through control of morphology, content exchange, inheritance of mitochondria, maintenance of mitochondrial DNA, and removal of damaged mitochondria by autophagy. Mitochondrial motility occurs through mechanical and molecular mechanisms which translocate mitochondria to sites of high energy demand. Motility also plays an important role in intracellular signaling. Here, we review key features that mediate mitochondrial dynamics and explore methods to advance the study of mitochondrial motility as well as mitochondrial dynamics-related diseases and mitochondrial-targeted therapeutics.
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Affiliation(s)
- Adam Green
- Department of Anesthesiology, The Ohio State University, Columbus, OH, United States
| | - Tanvir Hossain
- Department of Anesthesiology, The Ohio State University, Columbus, OH, United States
| | - David M. Eckmann
- Department of Anesthesiology, The Ohio State University, Columbus, OH, United States
- Center for Medical and Engineering Innovation, The Ohio State University, Columbus, OH, United States
- *Correspondence: David M. Eckmann,
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10
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Capristo M, Del Dotto V, Tropeano CV, Fiorini C, Caporali L, La Morgia C, Valentino ML, Montopoli M, Carelli V, Maresca A. Rapamycin rescues mitochondrial dysfunction in cells carrying the m.8344A > G mutation in the mitochondrial tRNA Lys. Mol Med 2022; 28:90. [PMID: 35922766 PMCID: PMC9347137 DOI: 10.1186/s10020-022-00519-z] [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: 02/18/2022] [Accepted: 07/25/2022] [Indexed: 11/25/2022] Open
Abstract
Background Myoclonus, Epilepsy and Ragged-Red-Fibers (MERRF) is a mitochondrial encephalomyopathy due to heteroplasmic mutations in mitochondrial DNA (mtDNA) most frequently affecting the tRNALys gene at position m.8344A > G. Defective tRNALys severely impairs mitochondrial protein synthesis and respiratory chain when a high percentage of mutant heteroplasmy crosses the threshold for full-blown clinical phenotype. Therapy is currently limited to symptomatic management of myoclonic epilepsy, and supportive measures to counteract muscle weakness with co-factors/supplements. Methods We tested two therapeutic strategies to rescue mitochondrial function in cybrids and fibroblasts carrying different loads of the m.8344A > G mutation. The first strategy was aimed at inducing mitochondrial biogenesis directly, over-expressing the master regulator PGC-1α, or indirectly, through the treatment with nicotinic acid, a NAD+ precursor. The second was aimed at stimulating the removal of damaged mitochondria through prolonged rapamycin treatment. Results The first approach slightly increased mitochondrial protein expression and respiration in the wild type and intermediate-mutation load cells, but was ineffective in high-mutation load cell lines. This suggests that induction of mitochondrial biogenesis may not be sufficient to rescue mitochondrial dysfunction in MERRF cells with high-mutation load. The second approach, when administered chronically (4 weeks), induced a slight increase of mitochondrial respiration in fibroblasts with high-mutation load, and a significant improvement in fibroblasts with intermediate-mutation load, rescuing completely the bioenergetics defect. This effect was mediated by increased mitochondrial biogenesis, possibly related to the rapamycin-induced inhibition of the Mechanistic Target of Rapamycin Complex 1 (mTORC1) and the consequent activation of the Transcription Factor EB (TFEB). Conclusions Overall, our results point to rapamycin-based therapy as a promising therapeutic option for MERRF. Supplementary Information The online version contains supplementary material available at 10.1186/s10020-022-00519-z.
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Affiliation(s)
- Mariantonietta Capristo
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy
| | - Valentina Del Dotto
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy
| | - Concetta Valentina Tropeano
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy
| | - Claudio Fiorini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy
| | - Leonardo Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy
| | - Chiara La Morgia
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy
| | - Maria Lucia Valentino
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy.,Department of Biomedical and NeuroMotor Sciences, University of Bologna, via Altura 3, 40139, Bologna, Italy
| | - Monica Montopoli
- Department of Pharmaceutical and Pharmacological Sciences, University of Padova, via Largo Meneghetti 2, 3513, Padova, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy. .,Department of Biomedical and NeuroMotor Sciences, University of Bologna, via Altura 3, 40139, Bologna, Italy.
| | - Alessandra Maresca
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, via Altura 3, 40139, Bologna, Italy.
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11
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Stokes JC, Bornstein RL, James K, Park KY, Spencer KA, Vo K, Snell JC, Johnson BM, Morgan PG, Sedensky MM, Baertsch NA, Johnson SC. Leukocytes mediate disease pathogenesis in the Ndufs4(KO) mouse model of Leigh syndrome. JCI Insight 2022; 7:156522. [PMID: 35050903 PMCID: PMC8983133 DOI: 10.1172/jci.insight.156522] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 01/19/2022] [Indexed: 11/23/2022] Open
Abstract
Symmetric, progressive, necrotizing lesions in the brainstem are a defining feature of Leigh syndrome (LS). A mechanistic understanding of the pathogenesis of these lesions has been elusive. Here, we report that leukocyte proliferation is causally involved in the pathogenesis of LS. Depleting leukocytes with a colony-stimulating factor 1 receptor inhibitor disrupted disease progression, including suppression of CNS lesion formation and a substantial extension of survival. Leukocyte depletion rescued diverse symptoms, including seizures, respiratory center function, hyperlactemia, and neurologic sequelae. These data reveal a mechanistic explanation for the beneficial effects of mTOR inhibition. More importantly, these findings dramatically alter our understanding of the pathogenesis of LS, demonstrating that immune involvement is causal in disease. This work has important implications for the mechanisms of mitochondrial disease and may lead to novel therapeutic strategies.
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Affiliation(s)
- Julia C Stokes
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - Rebecca L Bornstein
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States of America
| | - Katerina James
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - Kyung Yeon Park
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - Kira A Spencer
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - Katie Vo
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - John C Snell
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - Brittany M Johnson
- Department of Neurology, University of Washington, Seattle, United States of America
| | - Philip G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - Margaret M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, United States of America
| | - Nathan A Baertsch
- Department of Pediatrics, University of Washington, Seattle, United States of America
| | - Simon C Johnson
- Department of Neurology, University of Washington, Seattle, United States of America
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12
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Nozawa N, Noguchi M, Shinno K, Tajima M, Aizawa S, Saito T, Asada A, Ishii T, Ishizuka M, Iijima KM, Ando K. 5-Aminolevulinic acid and sodium ferrous citrate ameliorate muscle aging and extend healthspan in Drosophila. FEBS Open Bio 2021; 12:295-305. [PMID: 34854258 PMCID: PMC8727951 DOI: 10.1002/2211-5463.13338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 10/28/2021] [Accepted: 11/30/2021] [Indexed: 11/19/2022] Open
Abstract
Declines in mitochondrial functions are associated with aging. The combination of 5‐aminolevulinic acid (5‐ALA) and sodium ferrous citrate (SFC) improves mitochondrial functions in cultured cells. In this study, we investigated the effects of dietary supplementation with 5‐ALA and SFC (5‐ALA/SFC) on the healthspan and life span of Drosophila
melanogaster. Adult Drosophila fruit flies were fed cornmeal food containing various concentrations of 5‐ALA/SFC. Locomotor functions, life span, muscle architecture, and age‐associated changes in mitochondrial function were analyzed. We found that feeding 5‐ALA/SFC mitigated age‐associated declines in locomotor functions and extended organismal life span. Moreover, 5‐ALA/SFC preserved muscle architecture and maintained the mitochondrial membrane potential in aged animals. Since 5‐ALA phosphate/SFC is used as a human dietary supplement, our results suggest that it could be used to slow the age‐related declines in muscle functions, prevent age‐associated clinical conditions such as frailty, and extend healthspan and life span.
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Affiliation(s)
- Naoko Nozawa
- Graduate School of Science, Tokyo Metropolitan University, Japan.,Division of Pharmaceutical Research, SBI Pharmaceuticals Co., Ltd., Tokyo, Japan
| | - Marie Noguchi
- Graduate School of Science, Tokyo Metropolitan University, Japan
| | - Kanako Shinno
- Graduate School of Science, Tokyo Metropolitan University, Japan
| | - Maki Tajima
- Graduate School of Science, Tokyo Metropolitan University, Japan
| | - Shingo Aizawa
- Graduate School of Science, Tokyo Metropolitan University, Japan
| | - Taro Saito
- Graduate School of Science, Tokyo Metropolitan University, Japan.,Department of Biological Sciences, School of Science, Tokyo Metropolitan University, Japan
| | - Akiko Asada
- Graduate School of Science, Tokyo Metropolitan University, Japan.,Department of Biological Sciences, School of Science, Tokyo Metropolitan University, Japan
| | - Takuya Ishii
- Division of Pharmaceutical Research, SBI Pharmaceuticals Co., Ltd., Tokyo, Japan
| | - Masahiro Ishizuka
- Division of Pharmaceutical Research, SBI Pharmaceuticals Co., Ltd., Tokyo, Japan
| | - Koichi M Iijima
- Department of Neurogenetics, National Center for Geriatrics and Gerontology, Obu, Japan.,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
| | - Kanae Ando
- Graduate School of Science, Tokyo Metropolitan University, Japan.,Department of Biological Sciences, School of Science, Tokyo Metropolitan University, Japan
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13
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Thermal and Oxygen Flight Sensitivity in Ageing Drosophila melanogaster Flies: Links to Rapamycin-Induced Cell Size Changes. BIOLOGY 2021; 10:biology10090861. [PMID: 34571738 PMCID: PMC8464818 DOI: 10.3390/biology10090861] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/29/2021] [Accepted: 08/31/2021] [Indexed: 12/03/2022]
Abstract
Simple Summary Cold-blooded organisms can become physiologically challenged when performing highly oxygen-demanding activities (e.g., flight) across different thermal and oxygen environmental conditions. We explored whether this challenge decreases if an organism is built of smaller cells. This is because small cells create a large cell surface, which is costly, but can ease the delivery of oxygen to cells’ power plants, called mitochondria. We developed fruit flies in either standard food or food with rapamycin (a human drug altering the cell cycle and ageing), which produced flies with either large cells (no supplementation) or small cells (rapamycin supplementation). We measured the maximum speed at which flies were flapping their wings in warm and hot conditions, combined with either normal or reduced air oxygen concentrations. Flight intensity increased with temperature, and it was reduced by poor oxygen conditions, indicating limitations of flying insects by oxygen supply. Nevertheless, flies with small cells showed lower limitations, only slowing down their wing flapping in low oxygen in the hot environment. Our study suggests that small cells in a body can help cold-blooded organisms maintain demanding activities (e.g., flight), even in poor oxygen conditions, but this advantage can depend on body temperature. Abstract Ectotherms can become physiologically challenged when performing oxygen-demanding activities (e.g., flight) across differing environmental conditions, specifically temperature and oxygen levels. Achieving a balance between oxygen supply and demand can also depend on the cellular composition of organs, which either evolves or changes plastically in nature; however, this hypothesis has rarely been examined, especially in tracheated flying insects. The relatively large cell membrane area of small cells should increase the rates of oxygen and nutrient fluxes in cells; however, it does also increase the costs of cell membrane maintenance. To address the effects of cell size on flying insects, we measured the wing-beat frequency in two cell-size phenotypes of Drosophila melanogaster when flies were exposed to two temperatures (warm/hot) combined with two oxygen conditions (normoxia/hypoxia). The cell-size phenotypes were induced by rearing 15 isolines on either standard food (large cells) or rapamycin-enriched food (small cells). Rapamycin supplementation (downregulation of TOR activity) produced smaller flies with smaller wing epidermal cells. Flies generally flapped their wings at a slower rate in cooler (warm treatment) and less-oxygenated (hypoxia) conditions, but the small-cell-phenotype flies were less prone to oxygen limitation than the large-cell-phenotype flies and did not respond to the different oxygen conditions under the warm treatment. We suggest that ectotherms with small-cell life strategies can maintain physiologically demanding activities (e.g., flight) when challenged by oxygen-poor conditions, but this advantage may depend on the correspondence among body temperatures, acclimation temperatures and physiological thermal limits.
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Zhang Y, Zhang J, Wang S. The Role of Rapamycin in Healthspan Extension via the Delay of Organ Aging. Ageing Res Rev 2021; 70:101376. [PMID: 34089901 DOI: 10.1016/j.arr.2021.101376] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 05/07/2021] [Accepted: 05/30/2021] [Indexed: 12/17/2022]
Abstract
Aging can not only shorten a healthy lifespan, but can also lead to multi-organ dysfunction and failure. Anti-aging is a complex and worldwide conundrum for eliminating the various pathologies of senility. The past decade has seen great progress in the understanding of the aging-associated signaling pathways and their application for developing anti-aging approaches. Currently, some drugs can improve quality of life. The activation of mammalian target of rapamycin (mTOR) signaling is one of the core and detrimental mechanisms related to aging; rapamycin can reduce the rate of aging, improve age-related diseases by inhibiting the mTOR pathway, and prolong lifespan and healthspan effectively. However, the current evidence for rapamycin in lifespan extension and organ aging is fragmented and scattered. In this review, we summarize the efficacy and safety of rapamycin in prolonging a healthy lifespan by systematically alleviating aging in multiple organ systems, i.e., the nervous, urinary, digestive, circulatory, motor, respiratory, endocrine, reproductive, integumentary and immune systems, to provide a theoretical basis for the future clinical application of rapamycin in anti-aging.
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Affiliation(s)
- Yan Zhang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; National Clinical Research Center for Obstetrical and Gynecological Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Jinjin Zhang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; National Clinical Research Center for Obstetrical and Gynecological Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Shixuan Wang
- Department of Obstetrics and Gynecology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China; National Clinical Research Center for Obstetrical and Gynecological Diseases, Huazhong University of Science and Technology, Wuhan, 430030, China; Key Laboratory of Cancer Invasion and Metastasis, Ministry of Education, Huazhong University of Science and Technology, Wuhan, 430030, China.
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15
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Anti-aging: senolytics or gerostatics (unconventional view). Oncotarget 2021; 12:1821-1835. [PMID: 34504654 PMCID: PMC8416555 DOI: 10.18632/oncotarget.28049] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 07/05/2021] [Indexed: 12/17/2022] Open
Abstract
Senolytics are basically anti-cancer drugs, repurposed to kill senescent cells selectively. It is even more difficult to selectively kill senescent cells than to kill cancer cells. Based on lessons of cancer therapy, here I suggest how to exploit oncogene-addiction and to combine drugs to achieve selectivity. However, even if selective senolytic combinations will be developed, there is little evidence that a few senescent cells are responsible for organismal aging. I also discuss gerostatics, such as rapamycin and other rapalogs, pan-mTOR inhibitors, dual PI3K/mTOR inhibitors, which inhibit growth- and aging-promoting pathways. Unlike senolytics, gerostatics do not kill cells but slow down cellular geroconversion to senescence. Numerous studies demonstrated that inhibition of the mTOR pathways by any means (genetic, pharmacological and dietary) extends lifespan. Currently, only two studies demonstrated that senolytics (fisetin and a combination Dasatinib plus Quercetin) extend lifespan in mice. These senolytics slightly inhibit the mTOR pathway. Thus, life extension by these senolytics can be explained by their slight rapamycin-like (gerostatic) effects.
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16
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Genotype and Trait Specific Responses to Rapamycin Intake in Drosophila melanogaster. INSECTS 2021; 12:insects12050474. [PMID: 34065203 PMCID: PMC8161023 DOI: 10.3390/insects12050474] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 12/11/2022]
Abstract
Simple Summary Rapamycin is commonly used as an immunosuppressant, but also as an anti-aging medicine. Despite its widespread use, results suggest that there is large variability in drug efficiency among patients, and limited knowledge exists about potential side-effects. In the present study, we investigated the effects of rapamycin using the common fruit fly as model organism. Six genetically distinct lines were exposed to rapamycin, and the phenotypic consequence on fecundity, longevity and heat stress tolerance was quantified. Flies exposed to rapamycin had increased longevity and heat stress tolerance, however a side effect in the form of decreased fecundity was also observed. Our data clearly show that the costs and benefits of rapamycin treatment is strongly genotype dependent. These observations are important as they imply that a ‘one size fits all’ approach when it comes to rapamycin treatment is not advisable. Future studies should address the underlying genetic component that drive the drug response variability. Abstract Rapamycin is a powerful inhibitor of the TOR (Target of Rapamycin) pathway, which is an evolutionarily conserved protein kinase, that plays a central role in plants and animals. Rapamycin is used globally as an immunosuppressant and as an anti-aging medicine. Despite widespread use, treatment efficiency varies considerably across patients, and little is known about potential side effects. Here we seek to investigate the effects of rapamycin by using Drosophila melanogaster as model system. Six isogenic D. melanogaster lines were assessed for their fecundity, male longevity and male heat stress tolerance with or without rapamycin treatment. The results showed increased longevity and heat stress tolerance for male flies treated with rapamycin. Conversely, the fecundity of rapamycin-exposed individuals was lower than for flies from the non-treated group, suggesting unwanted side effects of the drug in D. melanogaster. We found strong evidence for genotype-by-treatment interactions suggesting that a ‘one size fits all’ approach when it comes to treatment with rapamycin is not recommendable. The beneficial responses to rapamycin exposure for stress tolerance and longevity are in agreement with previous findings, however, the unexpected effects on reproduction are worrying and need further investigation and question common believes that rapamycin constitutes a harmless drug.
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17
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An energetics perspective on geroscience: mitochondrial protonmotive force and aging. GeroScience 2021; 43:1591-1604. [PMID: 33864592 DOI: 10.1007/s11357-021-00365-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 04/07/2021] [Indexed: 12/13/2022] Open
Abstract
Mitochondria are organelles that provide energy to cells through ATP production. Mitochondrial dysfunction has long been postulated to mediate cellular declines that drive biological aging. Many well-characterized hallmarks of aging may involve underlying energetic defects that stem from loss of mitochondrial function with age. Why and how mitochondrial function declines with age is an open question and one that has been difficult to answer. Mitochondria are powered by an electrochemical gradient across the inner mitochondrial membrane known as the protonmotive force (PMF). This gradient decreases with age in several experimental models. However, it is unclear if a diminished PMF is a cause or a consequence of aging. Herein, we briefly review and define mitochondrial function, we summarize how PMF changes with age in several models, and we highlight recent studies that implicate PMF in aging biology. We also identify barriers that must be addressed for the field to progress. Emerging technology permits more precise in vivo study of mitochondria that will allow better understanding of cause and effect in metabolic models of aging. Once cause and effect can be discerned more precisely, energetics approaches to combat aging may be developed to prevent or reverse functional decline.
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18
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Blagosklonny MV. DNA- and telomere-damage does not limit lifespan: evidence from rapamycin. Aging (Albany NY) 2021; 13:3167-3175. [PMID: 33578394 PMCID: PMC7906135 DOI: 10.18632/aging.202674] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 02/10/2021] [Indexed: 12/13/2022]
Abstract
Failure of rapamycin to extend lifespan in DNA repair mutant and telomerase-knockout mice, while extending lifespan in normal mice, indicates that neither DNA damage nor telomere shortening limits normal lifespan or causes normal aging.
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19
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Pitceathly RD, Keshavan N, Rahman J, Rahman S. Moving towards clinical trials for mitochondrial diseases. J Inherit Metab Dis 2021; 44:22-41. [PMID: 32618366 PMCID: PMC8432143 DOI: 10.1002/jimd.12281] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 06/22/2020] [Accepted: 06/30/2020] [Indexed: 12/11/2022]
Abstract
Primary mitochondrial diseases represent some of the most common and severe inherited metabolic disorders, affecting ~1 in 4,300 live births. The clinical and molecular diversity typified by mitochondrial diseases has contributed to the lack of licensed disease-modifying therapies available. Management for the majority of patients is primarily supportive. The failure of clinical trials in mitochondrial diseases partly relates to the inefficacy of the compounds studied. However, it is also likely to be a consequence of the significant challenges faced by clinicians and researchers when designing trials for these disorders, which have historically been hampered by a lack of natural history data, biomarkers and outcome measures to detect a treatment effect. Encouragingly, over the past decade there have been significant advances in therapy development for mitochondrial diseases, with many small molecules now transitioning from preclinical to early phase human interventional studies. In this review, we present the treatments and management strategies currently available to people with mitochondrial disease. We evaluate the challenges and potential solutions to trial design and highlight the emerging pharmacological and genetic strategies that are moving from the laboratory to clinical trials for this group of disorders.
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Affiliation(s)
- Robert D.S. Pitceathly
- Department of Neuromuscular DiseasesUCL Queen Square Institute of Neurology and The National Hospital for Neurology and NeurosurgeryLondonUK
| | - Nandaki Keshavan
- Mitochondrial Research GroupUCL Great Ormond Street Institute of Child HealthLondonUK
- Metabolic UnitGreat Ormond Street Hospital for Children NHS Foundation TrustLondonUK
| | - Joyeeta Rahman
- Mitochondrial Research GroupUCL Great Ormond Street Institute of Child HealthLondonUK
| | - Shamima Rahman
- Mitochondrial Research GroupUCL Great Ormond Street Institute of Child HealthLondonUK
- Metabolic UnitGreat Ormond Street Hospital for Children NHS Foundation TrustLondonUK
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20
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Bottani E, Lamperti C, Prigione A, Tiranti V, Persico N, Brunetti D. Therapeutic Approaches to Treat Mitochondrial Diseases: "One-Size-Fits-All" and "Precision Medicine" Strategies. Pharmaceutics 2020; 12:E1083. [PMID: 33187380 PMCID: PMC7696526 DOI: 10.3390/pharmaceutics12111083] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 11/08/2020] [Accepted: 11/09/2020] [Indexed: 12/11/2022] Open
Abstract
Primary mitochondrial diseases (PMD) refer to a group of severe, often inherited genetic conditions due to mutations in the mitochondrial genome or in the nuclear genes encoding for proteins involved in oxidative phosphorylation (OXPHOS). The mutations hamper the last step of aerobic metabolism, affecting the primary source of cellular ATP synthesis. Mitochondrial diseases are characterized by extremely heterogeneous symptoms, ranging from organ-specific to multisystemic dysfunction with different clinical courses. The limited information of the natural history, the limitations of currently available preclinical models, coupled with the large variability of phenotypical presentations of PMD patients, have strongly penalized the development of effective therapies. However, new therapeutic strategies have been emerging, often with promising preclinical and clinical results. Here we review the state of the art on experimental treatments for mitochondrial diseases, presenting "one-size-fits-all" approaches and precision medicine strategies. Finally, we propose novel perspective therapeutic plans, either based on preclinical studies or currently used for other genetic or metabolic diseases that could be transferred to PMD.
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Affiliation(s)
- Emanuela Bottani
- Department of Diagnostics and Public Health, Section of Pharmacology, University of Verona, 37134 Verona, Italy
| | - Costanza Lamperti
- Medical Genetics and Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy; (C.L.); (V.T.)
| | - Alessandro Prigione
- Department of General Pediatrics, Neonatology, and Pediatric Cardiology, University Clinic Düsseldorf (UKD), Heinrich Heine University (HHU), 40225 Dusseldorf, Germany;
| | - Valeria Tiranti
- Medical Genetics and Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy; (C.L.); (V.T.)
| | - Nicola Persico
- Department of Clinical Science and Community Health, University of Milan, 20122 Milan, Italy;
- Fetal Medicine and Surgery Service, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milan, Italy
| | - Dario Brunetti
- Medical Genetics and Neurogenetics Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy; (C.L.); (V.T.)
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20129 Milan, Italy
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21
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Viscomi C, Zeviani M. Strategies for fighting mitochondrial diseases. J Intern Med 2020; 287:665-684. [PMID: 32100338 DOI: 10.1111/joim.13046] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/10/2019] [Accepted: 01/24/2020] [Indexed: 12/19/2022]
Abstract
Mitochondrial diseases are extremely heterogeneous genetic conditions characterized by faulty oxidative phosphorylation (OXPHOS). OXPHOS deficiency can be the result of mutation in mtDNA genes, encoding either proteins (13 subunits of the mitochondrial complexes I, III, IV and V) or the tRNA and rRNA components of the in situ mtDNA translation. The remaining mitochondrial disease genes are in the nucleus, encoding proteins with a huge variety of functions, from structural subunits of the mitochondrial complexes, to factors involved in their formation and regulation, components of the mtDNA replication and expression machinery, biosynthetic enzymes for the biosynthesis or incorporation of prosthetic groups, components of the mitochondrial quality control and proteostasis, enzymes involved in the clearance of toxic compounds, factors involved in the formation of the lipid milieu, etc. These different functions represent potential targets for 'general' therapeutic interventions, as they may be adapted to a number of different mitochondrial conditions. This is in contrast with 'tailored', personalized therapeutic approaches, such as gene therapy, cell therapy and organ replacement, that can be useful only for individual conditions. This review will present the most recent concepts emerged from preclinical work and the attempts to translate them into the clinics. The common notion that mitochondrial disorders have no cure is currently challenged by a massive effort of scientists and clinicians, and we do expect that thanks to this intensive investigation work and tangible results for the development of strategies amenable to the treatment of patients with these tremendously difficult conditions are not so far away.
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Affiliation(s)
- C Viscomi
- From the, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - M Zeviani
- Department of Neurosciences, University of Padova, Padova, Italy.,Venetian Institute of Molecular Medicine, Padova, Italy
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22
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Johnson SC, Kayser EB, Bornstein R, Stokes J, Bitto A, Park KY, Pan A, Sun G, Raftery D, Kaeberlein M, Sedensky MM, Morgan PG. Regional metabolic signatures in the Ndufs4(KO) mouse brain implicate defective glutamate/α-ketoglutarate metabolism in mitochondrial disease. Mol Genet Metab 2020; 130:118-132. [PMID: 32331968 PMCID: PMC7272141 DOI: 10.1016/j.ymgme.2020.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 03/29/2020] [Indexed: 02/08/2023]
Abstract
Leigh Syndrome (LS) is a mitochondrial disorder defined by progressive focal neurodegenerative lesions in specific regions of the brain. Defects in NDUFS4, a subunit of complex I of the mitochondrial electron transport chain, cause LS in humans; the Ndufs4 knockout mouse (Ndufs4(KO)) closely resembles the human disease. Here, we probed brain region-specific molecular signatures in pre-symptomatic Ndufs4(KO) to identify factors which underlie focal neurodegeneration. Metabolomics revealed that free amino acid concentrations are broadly different by region, and glucose metabolites are increased in a manner dependent on both region and genotype. We then tested the impact of the mTOR inhibitor rapamycin, which dramatically attenuates LS in Ndufs4(KO), on region specific metabolism. Our data revealed that loss of Ndufs4 drives pathogenic changes to CNS glutamine/glutamate/α-ketoglutarate metabolism which are rescued by mTOR inhibition Finally, restriction of the Ndufs4 deletion to pre-synaptic glutamatergic neurons recapitulated the whole-body knockout. Together, our findings are consistent with mTOR inhibition alleviating disease by increasing availability of α-ketoglutarate, which is both an efficient mitochondrial complex I substrate in Ndufs4(KO) and an important metabolite related to neurotransmitter metabolism in glutamatergic neurons.
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Affiliation(s)
- Simon C Johnson
- Department of Neurology, University of Washington, Seattle, WA 98105, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Ernst-Bernhard Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Rebecca Bornstein
- Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Julia Stokes
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA
| | - Alessandro Bitto
- Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Kyung Yeon Park
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Amanda Pan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Grace Sun
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Daniel Raftery
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Department of Chemistry, University of Washington, Seattle, WA 98109, United States
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Margaret M Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Philip G Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA.
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23
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Huynh N, Wang S, King-Jones K. Spatial and temporal control of gene manipulation in Drosophila via drug-activated Cas9 nucleases. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 120:103336. [PMID: 32105778 DOI: 10.1016/j.ibmb.2020.103336] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 06/10/2023]
Abstract
Advances in CRISPR/Cas9 have revolutionized molecular biology and greatly facilitated the ability to manipulate gene function through the creation of precisely engineered mutants. We recently reported a collection of modular gateway-compatible Cas9/gRNA Drosophila lines to interfere with gene expression in a tissue-specific manner, including polytene tissues. However, most current in vivo CRISPR/Cas9 tools cannot temporally control the induction of Cas9 or gRNAs via external stimuli such as RU486. A drug-inducible CRISPR/Cas9 system would allow studying genes at later stages where early lethality is an issue. This would be especially useful when combined with tissue-specific expression of Cas9 or gRNAs, allowing for full spatiotemporal control. Here, we present a RU486-inducible version of Cas9 and also show that a Rapamycin-inducible Cas9, previously used in mammalian cell culture, works in Drosophila as well. Both RU486 and rapamycin-inducible Cas9 work in vivo and in Drosophila cell culture. We also present split Cas9 constructs for rapamycin-dependent gene disruption and activation. These approaches establish drug-inducible and thus temporally controlled CRISPR/Cas9 tools for gene disruption and expression in a living model organism. Our CRISPR/Cas9 vector collection can be easily adapted for any tissue and provides higher fidelity compared to RNAi approaches.
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Affiliation(s)
- Nhan Huynh
- Department of Biological Sciences, Faculty of Sciences, University of Alberta, G-502 Biological Sciences Bldg., Edmonton, Alberta, T6G 2E9, Canada
| | - Song Wang
- Department of Biological Sciences, Faculty of Sciences, University of Alberta, G-502 Biological Sciences Bldg., Edmonton, Alberta, T6G 2E9, Canada
| | - Kirst King-Jones
- Department of Biological Sciences, Faculty of Sciences, University of Alberta, G-502 Biological Sciences Bldg., Edmonton, Alberta, T6G 2E9, Canada.
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24
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Perez-Gomez R, Magnin V, Mihajlovic Z, Slaninova V, Krejci A. Downregulation of respiratory complex I mediates major signalling changes triggered by TOR activation. Sci Rep 2020; 10:4401. [PMID: 32157127 PMCID: PMC7064613 DOI: 10.1038/s41598-020-61244-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 02/05/2020] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial dysfunctions belong amongst the most common metabolic diseases but the signalling networks that lead to the manifestation of a disease phenotype are often not well understood. We identified the subunits of respiratory complex I, III and IV as mediators of major signalling changes during Drosophila wing disc development. Their downregulation in larval wing disc leads to robust stimulation of TOR activity, which in turn orchestrates a complex downstream signalling network. Specifically, after downregulation of the complex I subunit ND-49 (mammalian NDUFS2), TOR activates JNK to induce cell death and ROS production essential for the stimulation of compensatory apoptosis-induced proliferation within the tissue. Additionally, TOR upregulates Notch and JAK/STAT signalling and it directs glycolytic switch of the target tissue. Our results highlight the central role of TOR signalling in mediating the complex response to mitochondrial respiratory dysfunction and they provide a rationale why the disease symptoms associated with respiratory dysfunctions are often alleviated by mTOR inhibitors.
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Affiliation(s)
- Raquel Perez-Gomez
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, Ceske Budejovice, Czech Republic.,University of South Bohemia, Faculty of Science, Ceske Budejovice, Czech Republic
| | - Valentina Magnin
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, Ceske Budejovice, Czech Republic.,University of South Bohemia, Faculty of Science, Ceske Budejovice, Czech Republic
| | - Zorana Mihajlovic
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, Ceske Budejovice, Czech Republic.,University of South Bohemia, Faculty of Science, Ceske Budejovice, Czech Republic
| | - Vera Slaninova
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, Ceske Budejovice, Czech Republic.,University of South Bohemia, Faculty of Science, Ceske Budejovice, Czech Republic
| | - Alena Krejci
- Czech Academy of Sciences, Biology Centre, Institute of Entomology, Ceske Budejovice, Czech Republic. .,University of South Bohemia, Faculty of Science, Ceske Budejovice, Czech Republic.
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25
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Rhooms SK, Murari A, Goparaju NSV, Vilanueva M, Owusu-Ansah E. Insights from Drosophila on mitochondrial complex I. Cell Mol Life Sci 2020; 77:607-618. [PMID: 31485716 PMCID: PMC7289077 DOI: 10.1007/s00018-019-03293-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 08/08/2019] [Accepted: 08/28/2019] [Indexed: 12/26/2022]
Abstract
NADH:ubiquinone oxidoreductase, more commonly referred to as mitochondrial complex I (CI), is the largest discrete enzyme of the oxidative phosphorylation system (OXPHOS). It is localized to the mitochondrial inner membrane. CI oxidizes NADH generated from the tricarboxylic acid cycle to NAD+, in a series of redox reactions that culminates in the reduction of ubiquinone, and the transport of protons from the matrix across the inner membrane to the intermembrane space. The resulting proton-motive force is consumed by ATP synthase to generate ATP, or harnessed to transport ions, metabolites and proteins into the mitochondrion. CI is also a major source of reactive oxygen species. Accordingly, impaired CI function has been associated with a host of chronic metabolic and degenerative disorders such as diabetes, cardiomyopathy, Parkinson's disease (PD) and Leigh syndrome. Studies on Drosophila have contributed to our understanding of the multiple roles of CI in bioenergetics and organismal physiology. Here, we explore and discuss some of the studies on Drosophila that have informed our understanding of this complex and conclude with some of the open questions about CI that can be resolved by studies on Drosophila.
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Affiliation(s)
- Shauna-Kay Rhooms
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, 10032, USA
| | - Anjaneyulu Murari
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, 10032, USA
| | - Naga Sri Vidya Goparaju
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, 10032, USA
| | - Maximino Vilanueva
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, 10032, USA
| | - Edward Owusu-Ansah
- Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, 10032, USA.
- The Robert N. Butler Columbia Aging Center, Columbia University Medical Center, New York, NY, 10032, USA.
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Heparan Sulfate Structure Affects Autophagy, Lifespan, Responses to Oxidative Stress, and Cell Degeneration in Drosophila parkin Mutants. G3-GENES GENOMES GENETICS 2020; 10:129-141. [PMID: 31672849 PMCID: PMC6945019 DOI: 10.1534/g3.119.400730] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autophagy is a catabolic process that provides cells with energy and molecular building blocks during nutritional stress. Autophagy also removes misfolded proteins and damaged organelles, a critical mechanism for cellular repair. Earlier work demonstrated that heparan sulfate proteoglycans, an abundant class of carbohydrate-modified proteins found on cell surfaces and in the extracellular matrix, suppress basal levels of autophagy in several cell types during development in Drosophila melanogaster. In studies reported here, we examined the capacity of heparan sulfate synthesis to influence events affected by autophagy, including lifespan, resistance to reactive oxygen species (ROS) stress, and accumulation of ubiquitin-modified proteins in the brain. Compromising heparan sulfate synthesis increased autophagy-dependent processes, evident by extended lifespan, increased resistance to ROS, and reduced accumulation of ubiquitin-modified proteins in the brains of ROS exposed adults. The capacity of altering heparan sulfate biosynthesis to protect cells from injury was also evaluated in two different models of neurodegeneration, overexpression of Presenilin and parkin mutants. Presenilin overexpression in the retina produces cell loss, and compromising heparan sulfate biosynthesis rescued retinal patterning and size abnormalities in these animals. parkin is the fly homolog of human PARK2, one of the genes responsible for juvenile onset Parkinson’s Disease. Parkin is involved in mitochondrial surveillance and compromising parkin function results in degeneration of both flight muscle and dopaminergic neurons in Drosophila. Altering heparan sulfate biosynthesis suppressed flight muscle degeneration and mitochondrial dysmorphology, indicating that activation of autophagy-mediated removal of mitochondria (mitophagy) is potentiated in these animals. These findings provide in vivo evidence that altering the levels of heparan sulfate synthesis activates autophagy and can provide protection from a variety of cellular stressors.
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27
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Sage-Schwaede A, Engelstad K, Salazar R, Curcio A, Khandji A, Garvin JH, De Vivo DC. Exploring mTOR inhibition as treatment for mitochondrial disease. Ann Clin Transl Neurol 2019; 6:1877-1881. [PMID: 31386302 PMCID: PMC6764630 DOI: 10.1002/acn3.50846] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 06/25/2019] [Indexed: 12/31/2022] Open
Abstract
Leigh syndrome and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) are two of the most frequent pediatric mitochondrial diseases. Both cause severe morbidity and neither have effective treatment. Inhibiting the mammalian target of rapamycin (mTOR) pathway has been shown in model mice of Leigh syndrome to extend lifespan and attenuate both the clinical and pathological progression of disease. Based on this observation, we treated two children with everolimus, a rapamycin analogue. The child with Leigh syndrome showed sustained benefit, while the child with MELAS failed to respond and died of progressive disease. We discuss possible mechanisms underlying these disparate responses to mTOR inhibition.
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Affiliation(s)
- Abigail Sage-Schwaede
- Department of Neurology, Columbia University Irving Medical Center, New York, New York, 10032
| | - Kristin Engelstad
- Department of Neurology, Columbia University Irving Medical Center, New York, New York, 10032
| | - Rachel Salazar
- Department of Neurology, Columbia University Irving Medical Center, New York, New York, 10032
| | - Angela Curcio
- Department of Neurology, Columbia University Irving Medical Center, New York, New York, 10032
| | - Alexander Khandji
- Neuroradiology Division, Radiology Department, Columbia University, New York University Irving Medical Center, Milstein Hospital Room 3-101, 177 Fort Washington Avenue, New York, New York, 10032
| | - James H Garvin
- Department of Pediatrics, Division of Pediatric Hematology, Oncology, and Stem Cell Transplantation, Columbia University Irving Medical Center, New York, New York, 10032
| | - Darryl C De Vivo
- Department of Neurology, Columbia University Irving Medical Center, New York, New York, 10032
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28
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Hirose M, Schilf P, Zarse K, Busch H, Fuellen G, Jöhren O, Köhling R, König IR, Richer B, Rupp J, Schwaninger M, Seeger K, Sina C, Ristow M, Ibrahim SM. Maternally Inherited Differences within Mitochondrial Complex I Control Murine Healthspan. Genes (Basel) 2019; 10:genes10070532. [PMID: 31337008 PMCID: PMC6678443 DOI: 10.3390/genes10070532] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 07/02/2019] [Accepted: 07/10/2019] [Indexed: 11/16/2022] Open
Abstract
Mitochondrial complex I-the largest enzyme complex of the mitochondrial oxidative phosphorylation machinery-has been proposed to contribute to a variety of age-related pathological alterations as well as longevity. The enzyme complex-consisting proteins are encoded by both nuclear (nDNA) and mitochondrial DNA (mtDNA). While some association studies of mtDNA encoded complex I genes and lifespan in humans have been reported, experimental evidence and the functional consequence of such variants is limited to studies using invertebrate models. Here, we present experimental evidence that a homoplasmic mutation in the mitochondrially encoded complex I gene mt-Nd2 modulates lifespan by altering cellular tryptophan levels and, consequently, ageing-related pathways in mice. A conplastic mouse strain carrying a mutation at m.4738C > A in mt-Nd2 lived slightly, but significantly, shorter than the controls did. The same mutation led to a higher susceptibility to glucose intolerance induced by high-fat diet feeding. These phenotypes were not observed in mice carrying a mutation in another mtDNA encoded complex I gene, mt-Nd5, suggesting the functional relevance of particular mutations in complex I to ageing and age-related diseases.
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Affiliation(s)
- Misa Hirose
- Luebeck Institute of Experimental Dermatology, University of Luebeck, 23562 Luebeck, Germany
| | - Paul Schilf
- Luebeck Institute of Experimental Dermatology, University of Luebeck, 23562 Luebeck, Germany
| | - Kim Zarse
- Energy Metabolism Laboratory, Institute of Translational Medicine, Swiss Federal Institute of Technology (ETH) Zurich, 8603 Schwerzenbach, Switzerland
| | - Hauke Busch
- Group of Systems Biology, Institute of Cardiogenetics and Luebeck Institute of Experimental Dermatology, University of Luebeck, 23562 Luebeck, Germany
| | - Georg Fuellen
- Institute for Biostatistics and Informatics in Medicine and Ageing Research, Rostock University Medical Center, 18057 Rostock, Germany
| | - Olaf Jöhren
- Center of Brain, Behavior & Metabolism, University of Luebeck, 23562 Luebeck, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, Rostock University Medical Center, 18057 Rostock, Germany
| | - Inke R König
- Institute of Medical Biometry and Statistics, University of Luebeck, 23562 Luebeck, Germany
| | - Barbara Richer
- Institute of Chemistry and Metabolomics, University of Luebeck, 23562 Luebeck, Germany
| | - Jan Rupp
- Department of Infectious Diseases and Microbiology, University of Luebeck, 23562 Luebeck, Germany
| | - Markus Schwaninger
- Institute of Experimental and Clinical Pharmacology and Toxicology, University of Luebeck, 23562 Luebeck, Germany
| | - Karsten Seeger
- Institute of Chemistry and Metabolomics, University of Luebeck, 23562 Luebeck, Germany
| | - Christian Sina
- Institute for Nutritional Medicine, University of Luebeck, 23562 Luebeck, Germany
| | - Michael Ristow
- Energy Metabolism Laboratory, Institute of Translational Medicine, Swiss Federal Institute of Technology (ETH) Zurich, 8603 Schwerzenbach, Switzerland
| | - Saleh M Ibrahim
- Luebeck Institute of Experimental Dermatology, University of Luebeck, 23562 Luebeck, Germany.
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29
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Zhang X, Yamashita S, Hara K, Doki T, Tawara N, Ikeda T, Misumi Y, Zhang Z, Matsuo Y, Nagai M, Kurashige T, Maruyama H, Ando Y. A mutantMATR3mouse model to explain multisystem proteinopathy. J Pathol 2019; 249:182-192. [DOI: 10.1002/path.5289] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 04/08/2019] [Accepted: 04/28/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Xiao Zhang
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Satoshi Yamashita
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Kentaro Hara
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Tsukasa Doki
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Nozomu Tawara
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Tokunori Ikeda
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
- Department of Clinical InvestigationKumamoto University Hospital Kumamoto Japan
| | - Yohei Misumi
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Ziwei Zhang
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Yoshimasa Matsuo
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
| | - Makiko Nagai
- Department of NeurologyKitasato University School of Medicine Sagamihara Japan
| | - Takashi Kurashige
- Department of NeurologyNational Hospital Organization Kure Medical Centre Kure Hiroshima Japan
- Department of Clinical Neuroscience and TherapeuticsHiroshima University Graduate School of Biomedical and Health Sciences Hiroshima Japan
| | - Hirofumi Maruyama
- Department of Clinical Neuroscience and TherapeuticsHiroshima University Graduate School of Biomedical and Health Sciences Hiroshima Japan
| | - Yukio Ando
- Department of Neurology, Graduate School of Medical SciencesKumamoto University Kumamoto Japan
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30
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Foriel S, Renkema GH, Lasarzewski Y, Berkhout J, Rodenburg RJ, Smeitink JAM, Beyrath J, Schenck A. A Drosophila Mitochondrial Complex I Deficiency Phenotype Array. Front Genet 2019; 10:245. [PMID: 30972103 PMCID: PMC6445954 DOI: 10.3389/fgene.2019.00245] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 03/05/2019] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial diseases are a group of rare life-threatening diseases often caused by defects in the oxidative phosphorylation system. No effective treatment is available for these disorders. Therapeutic development is hampered by the high heterogeneity in genetic, biochemical, and clinical spectra of mitochondrial diseases and by limited preclinical resources to screen and identify effective treatment candidates. Alternative models of the pathology are essential to better understand mitochondrial diseases and to accelerate the development of new therapeutics. The fruit fly Drosophila melanogaster is a cost- and time-efficient model that can recapitulate a wide range of phenotypes observed in patients suffering from mitochondrial disorders. We targeted three important subunits of complex I of the mitochondrial oxidative phosphorylation system with the flexible UAS-Gal4 system and RNA interference (RNAi): NDUFS4 (ND-18), NDUFS7 (ND-20), and NDUFV1 (ND-51). Using two ubiquitous driver lines at two temperatures, we established a collection of phenotypes relevant to complex I deficiencies. Our data offer models and phenotypes with different levels of severity that can be used for future therapeutic screenings. These include qualitative phenotypes that are amenable to high-throughput drug screening and quantitative phenotypes that require more resources but are likely to have increased potential and sensitivity to show modulation by drug treatment.
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Affiliation(s)
- Sarah Foriel
- Khondrion B.V., Nijmegen, Netherlands
- Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Radboud University Medical Center, Nijmegen, Netherlands
| | - G. Herma Renkema
- Khondrion B.V., Nijmegen, Netherlands
- Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Yvonne Lasarzewski
- Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Richard J. Rodenburg
- Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Jan A. M. Smeitink
- Khondrion B.V., Nijmegen, Netherlands
- Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Radboud University Medical Center, Nijmegen, Netherlands
| | | | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
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31
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Fan F, Sam R, Ryan E, Alvarado K, Villa-Cuesta E. Rapamycin as a potential treatment for succinate dehydrogenase deficiency. Heliyon 2019; 5:e01217. [PMID: 30805566 PMCID: PMC6374580 DOI: 10.1016/j.heliyon.2019.e01217] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 01/04/2019] [Accepted: 02/04/2019] [Indexed: 11/21/2022] Open
Abstract
Drosophila melanogaster is a powerful model to study mitochondrial respiratory chain defects, particularly succinate dehydrogenase (SDH) deficiency. Mutations in sdh genes cause degenerative disorders and often lead to death. Therapies for such pathologies are based on a combination of vitamins and dietary supplements, and are rarely effective. In Drosophila, mutations in several of the genes encoding SDH resemble the pathology of SDH deficiency in humans, enabling the Drosophila model to be used in finding treatments for this condition. Here we show that exposure to the drug rapamycin improves the survival of sdh mutant strains, the activity of SDH and the impaired climbing associated with sdh mutations. However, the production of reactive oxygen species, the oxygen consumption of isolated mitochondria and the resistance to hyperoxia were minimally affected. Our results contribute to the current research seeking a treatment for mitochondrial disease.
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Affiliation(s)
- Frances Fan
- Biology Department, Adelphi University, Garden City, NY, USA
- Honors College, Adelphi University, Garden City, NY, USA
| | - Rheba Sam
- Biology Department, Adelphi University, Garden City, NY, USA
- Honors College, Adelphi University, Garden City, NY, USA
| | - Emma Ryan
- Biology Department, Adelphi University, Garden City, NY, USA
- Honors College, Adelphi University, Garden City, NY, USA
| | | | - Eugenia Villa-Cuesta
- Biology Department, Adelphi University, Garden City, NY, USA
- NYU Winthrop Research Institute, Mineola, NY, USA
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32
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Shintani H, Shintani T, Ashida H, Sato M. Calorie Restriction Mimetics: Upstream-Type Compounds for Modulating Glucose Metabolism. Nutrients 2018; 10:E1821. [PMID: 30469486 PMCID: PMC6316630 DOI: 10.3390/nu10121821] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 11/16/2018] [Accepted: 11/18/2018] [Indexed: 12/20/2022] Open
Abstract
Calorie restriction (CR) can prolong the human lifespan, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition, while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-d-glucose, d-glucosamine, and d-allulose, which show antiaging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.
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Affiliation(s)
- Hideya Shintani
- Department of Internal Medicine, Saiseikai Izuo Hospital, Osaka 551-0032, Japan.
| | - Tomoya Shintani
- United Graduate School of Agricultural Science, Ehime University, Matsuyama 790-8577, Japan.
| | - Hisashi Ashida
- Faculty of Biology-Oriented Science and Technology, Kindai University, Wakayama 649-6493, Japan.
| | - Masashi Sato
- Faculty of Agriculture, Kagawa University, Kagawa 761-0701, Japan.
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33
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Towards a therapy for mitochondrial disease: an update. Biochem Soc Trans 2018; 46:1247-1261. [PMID: 30301846 PMCID: PMC6195631 DOI: 10.1042/bst20180134] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2018] [Revised: 09/07/2018] [Accepted: 09/10/2018] [Indexed: 02/07/2023]
Abstract
Preclinical work aimed at developing new therapies for mitochondrial diseases has recently given new hopes and opened unexpected perspectives for the patients affected by these pathologies. In contrast, only minor progresses have been achieved so far in the translation into the clinics. Many challenges are still ahead, including the need for a better characterization of the pharmacological effects of the different approaches and the design of appropriate clinical trials with robust outcome measures for this extremely heterogeneous, rare, and complex group of disorders. In this review, we will discuss the most important achievements and the major challenges in this very dynamic research field.
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34
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Abstract
Mutations of mtDNA accumulate in aging humans and other mammals to cause mitochondrial dysfunction in a subset of cells in various tissues. Furthermore, experimental induction of mtDNA mutations causes a premature aging syndrome in the mouse. To study if mitochondrial dysfunction is universally involved in shortening life span in metazoans, we generated a series of fruit fly lines with varying levels of mtDNA mutations. Unexpectedly, we report that fruit flies are remarkably tolerant to mtDNA mutations, as exemplified by their lack of effect on physiology and lifespan. Only an artificially induced, very drastic increase of the mtDNA mutation load will lead to reduced lifespan, showing that mtDNA mutations are unlikely to limit lifespan in natural fruit fly populations. Mammals develop age-associated clonal expansion of somatic mtDNA mutations resulting in severe respiratory chain deficiency in a subset of cells in a variety of tissues. Both mathematical modeling based on descriptive data from humans and experimental data from mtDNA mutator mice suggest that the somatic mutations are formed early in life and then undergo mitotic segregation during adult life to reach very high levels in certain cells. To address whether mtDNA mutations have a universal effect on aging metazoans, we investigated their role in physiology and aging of fruit flies. To this end, we utilized genetically engineered flies expressing mutant versions of the catalytic subunit of mitochondrial DNA polymerase (DmPOLγA) as a means to introduce mtDNA mutations. We report here that lifespan and health in fruit flies are remarkably tolerant to mtDNA mutations. Our results show that the short lifespan and wide genetic bottleneck of fruit flies are limiting the extent of clonal expansion of mtDNA mutations both in individuals and between generations. However, an increase of mtDNA mutations to very high levels caused sensitivity to mechanical and starvation stress, intestinal stem cell dysfunction, and reduced lifespan under standard conditions. In addition, the effects of dietary restriction, widely considered beneficial for organismal health, were attenuated in flies with very high levels of mtDNA mutations.
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35
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Buchanan JL, Meiklejohn CD, Montooth KL. Mitochondrial Dysfunction and Infection Generate Immunity-Fecundity Tradeoffs in Drosophila. Integr Comp Biol 2018; 58:591-603. [PMID: 29945242 PMCID: PMC6145415 DOI: 10.1093/icb/icy078] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Physiological responses to short-term environmental stressors, such as infection, can have long-term consequences for fitness, particularly if the responses are inappropriate or nutrient resources are limited. Genetic variation affecting energy acquisition, storage, and usage can limit cellular energy availability and may influence resource-allocation tradeoffs even when environmental nutrients are plentiful. Here, we utilized Drosophila mitochondrial-nuclear genotypes to test whether disrupted mitochondrial function interferes with nutrient-sensing pathways, and whether this disruption has consequences for tradeoffs between immunity and fecundity. We found that an energetically-compromised genotype was relatively resistant to rapamycin-a drug that targets nutrient-sensing pathways and mimics resource limitation. Dietary resource limitation decreased survival of energetically-compromised flies. Furthermore, survival of infection with a natural pathogen was decreased in this genotype, and females of this genotype experienced immunity-fecundity tradeoffs that were not evident in genotypic controls with normal energy metabolism. Together, these results suggest that this genotype may have little excess energetic capacity and fewer cellular nutrients, even when environmental nutrients are not limiting. Genetic variation in energy metabolism may therefore act to limit the resources available for allocation to life-history traits in ways that generate tradeoffs even when environmental resources are not limiting.
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Affiliation(s)
- Justin L Buchanan
- School of Biological Sciences, University of Nebraska–Lincoln, 1104 T St, Lincoln, NE 68588-0118, USA
| | - Colin D Meiklejohn
- School of Biological Sciences, University of Nebraska–Lincoln, 1104 T St, Lincoln, NE 68588-0118, USA
| | - Kristi L Montooth
- School of Biological Sciences, University of Nebraska–Lincoln, 1104 T St, Lincoln, NE 68588-0118, USA
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36
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Abstract
West syndrome (WS) is an early life epileptic encephalopathy associated with infantile spasms, interictal electroencephalography (EEG) abnormalities including high amplitude, disorganized background with multifocal epileptic spikes (hypsarrhythmia), and often neurodevelopmental impairments. Approximately 64% of the patients have structural, metabolic, genetic, or infectious etiologies and, in the rest, the etiology is unknown. Here we review the contribution of etiologies due to various metabolic disorders in the pathology of WS. These may include metabolic errors in organic molecules involved in amino acid and glucose metabolism, fatty acid oxidation, metal metabolism, pyridoxine deficiency or dependency, or acidurias in organelles such as mitochondria and lysosomes. We discuss the biochemical, clinical, and EEG features of these disorders as well as the evidence of how they may be implicated in the pathogenesis and treatment of WS. The early recognition of these etiologies in some cases may permit early interventions that may improve the course of the disease.
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Affiliation(s)
- Seda Salar
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Solomon L. Moshé
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Department of PediatricsMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
| | - Aristea S. Galanopoulou
- Laboratory of Developmental EpilepsySaul R. Korey Department of NeurologyMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
- Dominick P. Purpura Department of NeuroscienceMontefiore/Einstein Epilepsy CenterAlbert Einstein College of MedicineBronxNew YorkU.S.A.
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37
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Foriel S, Beyrath J, Eidhof I, Rodenburg RJ, Schenck A, Smeitink JAM. Feeding difficulties, a key feature of the Drosophila NDUFS4 mitochondrial disease model. Dis Model Mech 2018; 11:dmm032482. [PMID: 29590638 PMCID: PMC5897729 DOI: 10.1242/dmm.032482] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 02/26/2018] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial diseases are associated with a wide variety of clinical symptoms and variable degrees of severity. Patients with such diseases generally have a poor prognosis and often an early fatal disease outcome. With an incidence of 1 in 5000 live births and no curative treatments available, relevant animal models to evaluate new therapeutic regimes for mitochondrial diseases are urgently needed. By knocking down ND-18, the unique Drosophila ortholog of NDUFS4, an accessory subunit of the NADH:ubiquinone oxidoreductase (Complex I), we developed and characterized several dNDUFS4 models that recapitulate key features of mitochondrial disease. Like in humans, the dNDUFS4 KD flies display severe feeding difficulties, an aspect of mitochondrial disorders that has so far been largely ignored in animal models. The impact of this finding, and an approach to overcome it, will be discussed in the context of interpreting disease model characterization and intervention studies.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sarah Foriel
- Khondrion BV, Philips van Leydenlaan 15, 6525 EX, Nijmegen, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM) at the Department of Pediatrics, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6500 HB, Nijmegen, The Netherlands
| | - Julien Beyrath
- Khondrion BV, Philips van Leydenlaan 15, 6525 EX, Nijmegen, The Netherlands
| | - Ilse Eidhof
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Richard J Rodenburg
- Radboud Center for Mitochondrial Medicine (RCMM) at the Department of Pediatrics, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6500 HB, Nijmegen, The Netherlands
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Jan A M Smeitink
- Khondrion BV, Philips van Leydenlaan 15, 6525 EX, Nijmegen, The Netherlands
- Radboud Center for Mitochondrial Medicine (RCMM) at the Department of Pediatrics, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6500 HB, Nijmegen, The Netherlands
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Abstract
Inhibitors of mTOR, including clinically available rapalogs such as rapamycin (Sirolimus) and Everolimus, are gerosuppressants, which suppress cellular senescence. Rapamycin slows aging and extends life span in a variety of species from worm to mammals. Rapalogs can prevent age-related diseases, including cancer, atherosclerosis, obesity, neurodegeneration and retinopathy and potentially rejuvenate stem cells, immunity and metabolism. Here, I further suggest how rapamycin can be combined with metformin, inhibitors of angiotensin II signaling (Losartan, Lisinopril), statins (simvastatin, atorvastatin), propranolol, aspirin and a PDE5 inhibitor. Rational combinations of these drugs with physical exercise and an anti-aging diet (Koschei formula) can maximize their anti-aging effects and decrease side effects.
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39
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Lee MB, Kaeberlein M. Translational Geroscience: From invertebrate models to companion animal and human interventions. TRANSLATIONAL MEDICINE OF AGING 2018; 2:15-29. [PMID: 32368707 PMCID: PMC7198054 DOI: 10.1016/j.tma.2018.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Translational geroscience is an interdisciplinary field descended from basic gerontology that seeks to identify, validate, and clinically apply interventions to maximize healthy, disease-free lifespan. In this review, we describe a research pipeline for the identification and validation of lifespan extending interventions. Beginning in invertebrate model systems, interventions are discovered and then characterized using other invertebrate model systems (evolutionary translation), models of genetic diversity, and disease models. Vertebrate model systems, particularly mice, can then be utilized to validate interventions in mammalian systems. Collaborative, multi-site efforts, like the Interventions Testing Program (ITP), provide a key resource to assess intervention robustness in genetically diverse mice. Mouse disease models provide a tool to understand the broader utility of longevity interventions. Beyond mouse models, we advocate for studies in companion pets. The Dog Aging Project is an exciting example of translating research in dogs, both to develop a model system and to extend their healthy lifespan as a goal in itself. Finally, we discuss proposed and ongoing intervention studies in humans, unmet needs for validating interventions in humans, and speculate on how differences in survival among human populations may influence intervention efficacy.
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Affiliation(s)
- Mitchell B. Lee
- Department of Pathology, University of Washington, Seattle, WA USA
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA USA
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40
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Ito TK, Lu C, Khan J, Nguyen Q, Huang HZ, Kim D, Phillips J, Tan J, Lee Y, Nguyen T, Khessib S, Lim N, Mekvanich S, Oh J, Pineda VV, Wang W, Bitto A, An JY, Morton JF, Setou M, Ladiges WC, Kaeberlein M. Hepatic S6K1 Partially Regulates Lifespan of Mice with Mitochondrial Complex I Deficiency. Front Genet 2017; 8:113. [PMID: 28919908 PMCID: PMC5585733 DOI: 10.3389/fgene.2017.00113] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/16/2017] [Indexed: 01/09/2023] Open
Abstract
The inactivation of ribosomal protein S6 kinase 1 (S6K1) recapitulates aspects of caloric restriction and mTORC1 inhibition to achieve prolonged longevity in invertebrate and mouse models. In addition to delaying normative aging, inhibition of mTORC1 extends the shortened lifespan of yeast, fly, and mouse models with severe mitochondrial disease. Here we tested whether disruption of S6K1 can recapitulate the beneficial effects of mTORC1 inhibition in the Ndufs4 knockout (NKO) mouse model of Leigh Syndrome caused by Complex I deficiency. These NKO mice develop profound neurodegeneration resulting in brain lesions and death around 50–60 days of age. Our results show that liver-specific, as well as whole body, S6K1 deletion modestly prolongs survival and delays onset of neurological symptoms in NKO mice. In contrast, we observed no survival benefit in NKO mice specifically disrupted for S6K1 in neurons or adipocytes. Body weight was reduced in WT mice upon disruption of S6K1 in adipocytes or whole body, but not altered when S6K1 was disrupted only in neurons or liver. Taken together, these data indicate that decreased S6K1 activity in liver is sufficient to delay the neurological and survival defects caused by deficiency of Complex I and suggest that mTOR signaling can modulate mitochondrial disease and metabolism via cell non-autonomous mechanisms.
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Affiliation(s)
- Takashi K Ito
- Department of Pathology, University of WashingtonSeattle, WA, United States.,Department of Cellular and Molecular Anatomy, Hamamatsu University School of MedicineHamamatsu, Japan.,International Mass Imaging Center, Hamamatsu University School of MedicineHamamatsu, Japan
| | - Chenhao Lu
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Jacob Khan
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Quy Nguyen
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Heather Z Huang
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Dayae Kim
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - James Phillips
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Jo Tan
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Yenna Lee
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Tuyet Nguyen
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Samy Khessib
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Natalie Lim
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Surapat Mekvanich
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Joshua Oh
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Victor V Pineda
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Weirong Wang
- Department of Pathology, University of WashingtonSeattle, WA, United States.,Research Institute of Atherosclerotic Disease, Xi'an Jiaotong University Cardiovascular Research CenterXi'an, China.,Laboratory Animal Center, Xi'an Jiaotong University Health Science CenterXi'an, China
| | - Alessandro Bitto
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - Jonathan Y An
- Department of Pathology, University of WashingtonSeattle, WA, United States
| | - John F Morton
- Department of Comparative Medicine, University of WashingtonSeattle, WA, United States
| | - Mitsutoshi Setou
- Department of Cellular and Molecular Anatomy, Hamamatsu University School of MedicineHamamatsu, Japan.,International Mass Imaging Center, Hamamatsu University School of MedicineHamamatsu, Japan
| | - Warren C Ladiges
- Department of Comparative Medicine, University of WashingtonSeattle, WA, United States
| | - Matt Kaeberlein
- Department of Pathology, University of WashingtonSeattle, WA, United States
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Awad AM, Venkataramanan S, Nag A, Galivanche AR, Bradley MC, Neves LT, Douglass S, Clarke CF, Johnson TL. Chromatin-remodeling SWI/SNF complex regulates coenzyme Q 6 synthesis and a metabolic shift to respiration in yeast. J Biol Chem 2017; 292:14851-14866. [PMID: 28739803 DOI: 10.1074/jbc.m117.798397] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/17/2017] [Indexed: 12/13/2022] Open
Abstract
Despite its relatively streamlined genome, there are many important examples of regulated RNA splicing in Saccharomyces cerevisiae Here, we report a role for the chromatin remodeler SWI/SNF in respiration, partially via the regulation of splicing. We find that a nutrient-dependent decrease in Snf2 leads to an increase in splicing of the PTC7 transcript. The spliced PTC7 transcript encodes a mitochondrial phosphatase regulator of biosynthesis of coenzyme Q6 (ubiquinone or CoQ6) and a mitochondrial redox-active lipid essential for electron and proton transport in respiration. Increased splicing of PTC7 increases CoQ6 levels. The increase in PTC7 splicing occurs at least in part due to down-regulation of ribosomal protein gene expression, leading to the redistribution of spliceosomes from this abundant class of intron-containing RNAs to otherwise poorly spliced transcripts. In contrast, a protein encoded by the nonspliced isoform of PTC7 represses CoQ6 biosynthesis. Taken together, these findings uncover a link between Snf2 expression and the splicing of PTC7 and establish a previously unknown role for the SWI/SNF complex in the transition of yeast cells from fermentative to respiratory modes of metabolism.
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Affiliation(s)
- Agape M Awad
- From the Department of Chemistry and Biochemistry.,the Molecular Biology Institute, and
| | - Srivats Venkataramanan
- the Molecular Biology Institute, and.,the Department of Molecular Cell and Developmental Biology, UCLA, Los Angeles, California 90095
| | - Anish Nag
- From the Department of Chemistry and Biochemistry.,the Molecular Biology Institute, and
| | - Anoop Raj Galivanche
- the Department of Molecular Cell and Developmental Biology, UCLA, Los Angeles, California 90095
| | - Michelle C Bradley
- From the Department of Chemistry and Biochemistry.,the Molecular Biology Institute, and
| | - Lauren T Neves
- the Molecular Biology Institute, and.,the Department of Molecular Cell and Developmental Biology, UCLA, Los Angeles, California 90095
| | - Stephen Douglass
- the Department of Molecular Cell and Developmental Biology, UCLA, Los Angeles, California 90095
| | - Catherine F Clarke
- From the Department of Chemistry and Biochemistry, .,the Molecular Biology Institute, and
| | - Tracy L Johnson
- the Molecular Biology Institute, and .,the Department of Molecular Cell and Developmental Biology, UCLA, Los Angeles, California 90095
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