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Vila-Sanjurjo A, Mallo N, Atkins JF, Elson JL, Smith PM. Our current understanding of the toxicity of altered mito-ribosomal fidelity during mitochondrial protein synthesis: What can it tell us about human disease? Front Physiol 2023; 14:1082953. [PMID: 37457031 PMCID: PMC10349377 DOI: 10.3389/fphys.2023.1082953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/28/2023] [Indexed: 07/18/2023] Open
Abstract
Altered mito-ribosomal fidelity is an important and insufficiently understood causative agent of mitochondrial dysfunction. Its pathogenic effects are particularly well-known in the case of mitochondrially induced deafness, due to the existence of the, so called, ototoxic variants at positions 847C (m.1494C) and 908A (m.1555A) of 12S mitochondrial (mt-) rRNA. It was shown long ago that the deleterious effects of these variants could remain dormant until an external stimulus triggered their pathogenicity. Yet, the link from the fidelity defect at the mito-ribosomal level to its phenotypic manifestation remained obscure. Recent work with fidelity-impaired mito-ribosomes, carrying error-prone and hyper-accurate mutations in mito-ribosomal proteins, have started to reveal the complexities of the phenotypic manifestation of mito-ribosomal fidelity defects, leading to a new understanding of mtDNA disease. While much needs to be done to arrive to a clear picture of how defects at the level of mito-ribosomal translation eventually result in the complex patterns of disease observed in patients, the current evidence indicates that altered mito-ribosome function, even at very low levels, may become highly pathogenic. The aims of this review are three-fold. First, we compare the molecular details associated with mito-ribosomal fidelity to those of general ribosomal fidelity. Second, we gather information on the cellular and organismal phenotypes associated with defective translational fidelity in order to provide the necessary grounds for an understanding of the phenotypic manifestation of defective mito-ribosomal fidelity. Finally, the results of recent experiments directly tackling mito-ribosomal fidelity are reviewed and future paths of investigation are discussed.
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Affiliation(s)
- Antón Vila-Sanjurjo
- Grupo GIBE, Departamento de Bioloxía e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - Natalia Mallo
- Grupo GIBE, Departamento de Bioloxía e Centro de Investigacións Científicas Avanzadas (CICA), Universidade da Coruña (UDC), A Coruña, Spain
| | - John F Atkins
- Schools of Biochemistry and Microbiology, University College Cork, Cork, Ireland
| | - Joanna L Elson
- The Bioscience Institute, Newcastle University, Newcastle uponTyne, United Kingdom
- Human Metabolomics, North-West University, Potchefstroom, South Africa
| | - Paul M Smith
- Department of Paediatrics, Raigmore Hospital, Inverness, Scotland, United Kingdom
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2
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Paccosi E, Balajee AS, Proietti-De-Santis L. A matter of delicate balance: Loss and gain of Cockayne syndrome proteins in premature aging and cancer. FRONTIERS IN AGING 2022; 3:960662. [PMID: 35935726 PMCID: PMC9351357 DOI: 10.3389/fragi.2022.960662] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 07/04/2022] [Indexed: 12/26/2022]
Abstract
DNA repair genes are critical for preserving genomic stability and it is well established that mutations in DNA repair genes give rise to progeroid diseases due to perturbations in different DNA metabolic activities. Cockayne Syndrome (CS) is an autosomal recessive inheritance caused by inactivating mutations in CSA and CSB genes. This review will primarily focus on the two Cockayne Syndrome proteins, CSA and CSB, primarily known to be involved in Transcription Coupled Repair (TCR). Curiously, dysregulated expression of CS proteins has been shown to exhibit differential health outcomes: lack of CS proteins due to gene mutations invariably leads to complex premature aging phenotypes, while excess of CS proteins is associated with carcinogenesis. Thus it appears that CS genes act as a double-edged sword whose loss or gain of expression leads to premature aging and cancer. Future mechanistic studies on cell and animal models of CS can lead to potential biological targets for interventions in both aging and cancer development processes. Some of these exciting possibilities will be discussed in this review in light of the current literature.
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Affiliation(s)
- Elena Paccosi
- Unit of Molecular Genetics of Aging, Department of Ecology and Biology, University of Tuscia, Viterbo, Italy
- *Correspondence: Elena Paccosi, ; Adayabalam S. Balajee, ; Luca Proietti-De-Santis,
| | - Adayabalam S. Balajee
- Cytogenetic Biodosimetry Laboratory, Radiation Emergency Assistance Center/Training Site, Oak Ridge Institute of Science and Education, Oak Ridge Associated Universities, Oak Ridge, TN, United States
- *Correspondence: Elena Paccosi, ; Adayabalam S. Balajee, ; Luca Proietti-De-Santis,
| | - Luca Proietti-De-Santis
- Unit of Molecular Genetics of Aging, Department of Ecology and Biology, University of Tuscia, Viterbo, Italy
- *Correspondence: Elena Paccosi, ; Adayabalam S. Balajee, ; Luca Proietti-De-Santis,
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3
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Martinez-Miguel VE, Lujan C, Espie-Caullet T, Martinez-Martinez D, Moore S, Backes C, Gonzalez S, Galimov ER, Brown AEX, Halic M, Tomita K, Rallis C, von der Haar T, Cabreiro F, Bjedov I. Increased fidelity of protein synthesis extends lifespan. Cell Metab 2021; 33:2288-2300.e12. [PMID: 34525330 PMCID: PMC8570412 DOI: 10.1016/j.cmet.2021.08.017] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 05/06/2021] [Accepted: 08/30/2021] [Indexed: 12/20/2022]
Abstract
Loss of proteostasis is a fundamental process driving aging. Proteostasis is affected by the accuracy of translation, yet the physiological consequence of having fewer protein synthesis errors during multi-cellular organismal aging is poorly understood. Our phylogenetic analysis of RPS23, a key protein in the ribosomal decoding center, uncovered a lysine residue almost universally conserved across all domains of life, which is replaced by an arginine in a small number of hyperthermophilic archaea. When introduced into eukaryotic RPS23 homologs, this mutation leads to accurate translation, as well as heat shock resistance and longer life, in yeast, worms, and flies. Furthermore, we show that anti-aging drugs such as rapamycin, Torin1, and trametinib reduce translation errors, and that rapamycin extends further organismal longevity in RPS23 hyperaccuracy mutants. This implies a unified mode of action for diverse pharmacological anti-aging therapies. These findings pave the way for identifying novel translation accuracy interventions to improve aging.
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Affiliation(s)
| | - Celia Lujan
- UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Tristan Espie-Caullet
- UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6DD, UK
| | - Daniel Martinez-Martinez
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Saul Moore
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Cassandra Backes
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Suam Gonzalez
- School of Health, Sport and Bioscience, University of East London, Water Lane, London E15 4LZ, UK
| | - Evgeniy R Galimov
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - André E X Brown
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK
| | - Mario Halic
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Kazunori Tomita
- Centre for Genome Engineering and Maintenance, College of Health, Medicine and Life Sciences, Brunel University London, London UB8 3PH, UK
| | - Charalampos Rallis
- School of Health, Sport and Bioscience, University of East London, Water Lane, London E15 4LZ, UK
| | - Tobias von der Haar
- Kent Fungal Group, School of Biosciences, Division of Natural Sciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Filipe Cabreiro
- MRC London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK; Institute of Clinical Sciences, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London W12 0NN, UK; Cologne Excellence Cluster for Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Joseph Stelzmann Strasse 26, 50931 Cologne, Germany.
| | - Ivana Bjedov
- UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6DD, UK; Department of Medical Physics and Biomedical Engineering, University College London, Malet Place Engineering Building, Gower Street, London WC1E 6BT, UK.
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4
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Bjedov I, Rallis C. The Target of Rapamycin Signalling Pathway in Ageing and Lifespan Regulation. Genes (Basel) 2020; 11:E1043. [PMID: 32899412 PMCID: PMC7565554 DOI: 10.3390/genes11091043] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 08/28/2020] [Accepted: 08/30/2020] [Indexed: 12/11/2022] Open
Abstract
Ageing is a complex trait controlled by genes and the environment. The highly conserved mechanistic target of rapamycin signalling pathway (mTOR) is a major regulator of lifespan in all eukaryotes and is thought to be mediating some of the effects of dietary restriction. mTOR is a rheostat of energy sensing diverse inputs such as amino acids, oxygen, hormones, and stress and regulates lifespan by tuning cellular functions such as gene expression, ribosome biogenesis, proteostasis, and mitochondrial metabolism. Deregulation of the mTOR signalling pathway is implicated in multiple age-related diseases such as cancer, neurodegeneration, and auto-immunity. In this review, we briefly summarise some of the workings of mTOR in lifespan and ageing through the processes of transcription, translation, autophagy, and metabolism. A good understanding of the pathway's outputs and connectivity is paramount towards our ability for genetic and pharmacological interventions for healthy ageing and amelioration of age-related disease.
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Affiliation(s)
- Ivana Bjedov
- UCL Cancer Institute, Paul O’Gorman Building, 72 Huntley Street, London WC1E 6DD, UK
| | - Charalampos Rallis
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
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Phan T, Khalid F, Iben S. Nucleolar and Ribosomal Dysfunction-A Common Pathomechanism in Childhood Progerias? Cells 2019; 8:E534. [PMID: 31167386 PMCID: PMC6627804 DOI: 10.3390/cells8060534] [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: 04/22/2019] [Revised: 05/21/2019] [Accepted: 06/02/2019] [Indexed: 01/03/2023] Open
Abstract
The nucleolus organizes around the sites of transcription by RNA polymerase I (RNA Pol I). rDNA transcription by this enzyme is the key step of ribosome biogenesis and most of the assembly and maturation processes of the ribosome occur co-transcriptionally. Therefore, disturbances in rRNA transcription and processing translate to ribosomal malfunction. Nucleolar malfunction has recently been described in the classical progeria of childhood, Hutchinson-Gilford syndrome (HGPS), which is characterized by severe signs of premature aging, including atherosclerosis, alopecia, and osteoporosis. A deregulated ribosomal biogenesis with enlarged nucleoli is not only characteristic for HGPS patients, but it is also found in the fibroblasts of "normal" aging individuals. Cockayne syndrome (CS) is also characterized by signs of premature aging, including the loss of subcutaneous fat, alopecia, and cataracts. It has been shown that all genes in which a mutation causes CS, are involved in rDNA transcription by RNA Pol I. A disturbed ribosomal biogenesis affects mitochondria and translates into ribosomes with a reduced translational fidelity that causes endoplasmic reticulum (ER) stress and apoptosis. Therefore, it is speculated that disease-causing disturbances in the process of ribosomal biogenesis may be more common than hitherto anticipated.
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Affiliation(s)
- Tamara Phan
- Department of Dermatology, Ulm University, James-Franck Ring N27, 89081 Ulm, Germany.
| | - Fatima Khalid
- Department of Dermatology, Ulm University, James-Franck Ring N27, 89081 Ulm, Germany.
| | - Sebastian Iben
- Department of Dermatology, Ulm University, James-Franck Ring N27, 89081 Ulm, Germany.
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von der Haar T, Leadsham JE, Sauvadet A, Tarrant D, Adam IS, Saromi K, Laun P, Rinnerthaler M, Breitenbach-Koller H, Breitenbach M, Tuite MF, Gourlay CW. The control of translational accuracy is a determinant of healthy ageing in yeast. Open Biol 2017; 7:rsob.160291. [PMID: 28100667 PMCID: PMC5303280 DOI: 10.1098/rsob.160291] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 12/08/2016] [Indexed: 12/18/2022] Open
Abstract
Life requires the maintenance of molecular function in the face of stochastic processes that tend to adversely affect macromolecular integrity. This is particularly relevant during ageing, as many cellular functions decline with age, including growth, mitochondrial function and energy metabolism. Protein synthesis must deliver functional proteins at all times, implying that the effects of protein synthesis errors like amino acid misincorporation and stop-codon read-through must be minimized during ageing. Here we show that loss of translational accuracy accelerates the loss of viability in stationary phase yeast. Since reduced translational accuracy also reduces the folding competence of at least some proteins, we hypothesize that negative interactions between translational errors and age-related protein damage together overwhelm the cellular chaperone network. We further show that multiple cellular signalling networks control basal error rates in yeast cells, including a ROS signal controlled by mitochondrial activity, and the Ras pathway. Together, our findings indicate that signalling pathways regulating growth, protein homeostasis and energy metabolism may jointly safeguard accurate protein synthesis during healthy ageing.
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Affiliation(s)
- Tobias von der Haar
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Jane E Leadsham
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Aimie Sauvadet
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Daniel Tarrant
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Ilectra S Adam
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Kofo Saromi
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Peter Laun
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasser 34, 5020 Salzburg, Austria
| | - Mark Rinnerthaler
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasser 34, 5020 Salzburg, Austria
| | | | - Michael Breitenbach
- Department of Cell Biology, University of Salzburg, Hellbrunnerstrasser 34, 5020 Salzburg, Austria
| | - Mick F Tuite
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
| | - Campbell W Gourlay
- Kent Fungal Group, School of Biosciences, University of Kent, Canterbury CT2 7NJ, UK
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7
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Salminen A, Kauppinen A, Kaarniranta K. 2-Oxoglutarate-dependent dioxygenases are sensors of energy metabolism, oxygen availability, and iron homeostasis: potential role in the regulation of aging process. Cell Mol Life Sci 2015; 72:3897-914. [PMID: 26118662 PMCID: PMC11114064 DOI: 10.1007/s00018-015-1978-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 06/10/2015] [Accepted: 06/22/2015] [Indexed: 02/06/2023]
Abstract
Recent studies have revealed that the members of an ancient family of nonheme Fe(2+)/2-oxoglutarate-dependent dioxygenases (2-OGDO) are involved in the functions associated with the aging process. 2-Oxoglutarate and O2 are the obligatory substrates and Fe(2+) a cofactor in the activation of 2-OGDO enzymes, which can induce the hydroxylation of distinct proteins and the demethylation of DNA and histones. For instance, ten-eleven translocation 1-3 (TET1-3) are the demethylases of DNA, whereas Jumonji C domain-containing histone lysine demethylases (KDM2-7) are the major epigenetic regulators of chromatin landscape, known to be altered with aging. The functions of hypoxia-inducible factor (HIF) prolyl hydroxylases (PHD1-3) as well as those of collagen hydroxylases are associated with age-related degeneration. Moreover, the ribosomal hydroxylase OGFOD1 controls mRNA translation, which is known to decline with aging. 2-OGDO enzymes are the sensors of energy metabolism, since the Krebs cycle intermediate 2-oxoglutarate is an activator whereas succinate and fumarate are the potent inhibitors of 2-OGDO enzymes. In addition, O2 availability and iron redox homeostasis control the activities of 2-OGDO enzymes in tissues. We will briefly elucidate the catalytic mechanisms of 2-OGDO enzymes and then review the potential functions of the above-mentioned 2-OGDO enzymes in the control of the aging process.
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Affiliation(s)
- Antero Salminen
- Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
| | - Anu Kauppinen
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland
- Department of Ophthalmology, Kuopio University Hospital, P.O.B. 100, 70029, Kuopio, Finland
| | - Kai Kaarniranta
- Department of Ophthalmology, Institute of Clinical Medicine, University of Eastern Finland, P.O. Box 1627, 70211, Kuopio, Finland.
- Department of Ophthalmology, Kuopio University Hospital, P.O.B. 100, 70029, Kuopio, Finland.
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8
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Gautam S, Kalidindi R, Humayun MZ. SOS induction and mutagenesis by dnaQ missense alleles in wild type cells. Mutat Res 2012; 735:46-50. [PMID: 22677460 DOI: 10.1016/j.mrfmmm.2012.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 05/14/2012] [Accepted: 05/25/2012] [Indexed: 01/03/2023]
Abstract
Mistranslation leads to elevated mutagenesis and replication arrest, both of which are hypothesized to result from the presence of mixed populations of wild type and mistranslated versions of DNA polymerase III subunit proteins. Consistent with this possibility, expression of missense alleles of dnaQ (which codes for the proofreading subunit ɛ) in wild type (dnaQ+) cells is shown to lead to SOS induction as well as mutagenesis. Exposure to sublethal concentrations of streptomycin, an aminoglycoside antibiotic known to promote mistranslation, also leads to SOS induction.
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Affiliation(s)
- Satyendra Gautam
- University of Medicine and Dentistry of New Jersey - New Jersey Medical School, Department of Microbiology and Molecular Genetics, 225 Warren Street, ICPH-E450V, Newark NJ 07101-1709, United States
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Scheckhuber CQ, Osiewacz HD. Podospora anserina: a model organism to study mechanisms of healthy ageing. Mol Genet Genomics 2008; 280:365-74. [PMID: 18797929 DOI: 10.1007/s00438-008-0378-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Accepted: 08/29/2008] [Indexed: 12/18/2022]
Abstract
The filamentous ascomycete Podospora anserina has been extensively studied as an experimental ageing model for more than 50 years. As a result, a huge body of data has been accumulated and various molecular pathways have been identified as part of a molecular network involved in the control of ageing and life span. The aim of this review is to summarize data on P. anserina ageing, including aspects like respiration, cellular copper homeostasis, mitochondrial DNA (mtDNA) stability/instability, mitochondrial dynamics, apoptosis, translation efficiency and pathways directed against oxidative stress. It becomes clear that manipulation of several of these pathways bears the potential to extend the healthy period of time, the health span, within the life time of the fungus. Here we put special attention on recent work aimed to identify and characterize this type of long-lived P. anserina mutants. The study of the molecular pathways which are modified in these mutants can be expected to provide important clues for the elucidation of the mechanistic basis of this type of 'healthy ageing' at the organism level.
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Affiliation(s)
- Christian Q Scheckhuber
- Cluster of Excellence Macromolecular Complexes and Faculty for Biosciences, Molecular Developmental Biology, Johann Wolfgang Goethe University, Max-von-Laue-Str. 9, 60438, Frankfurt/Main, Germany
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Abstract
Whether or not bacteria divide symmetrically, the inheritance of cell poles is always asymmetrical. Because each cell carries an old and a new pole, its daughters will not be the same. Tracking poles of cells and measuring their lengths and doubling times in micro-colonies, Stewart et al.1 observed that growth rate diminished in cells inheriting old poles and concluded that these cells are susceptible to aging. Here, their results are compared with studies on the variabilities of length and age at division. It is argued that the decreased growth rate in old pole cells falls within the expected variation and may therefore be sufficiently far from a catastrophe-like cell death through aging.
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Affiliation(s)
- Conrad L Woldringh
- Section Molecular Cytology, Swammerdam Institute for Life Sciences, BioCentrum Amsterdam, University of Amsterdam, Kruislaan 316, 1098 SM Amsterdam, The Netherlands.
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11
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Abstract
Bacteria enjoy an infinite capacity for reproduction as long as they reside in an environment supporting growth. However, their rapid growth and efficient metabolism ultimately results in depletion of growth-supporting substrates and the population of cells enters a phase defined as the stationary phase of growth. In this phase, their reproductive ability is gradually lost. The molecular mechanism underlying this cellular degeneration has not been fully deciphered. Still, recent analysis of the physiology and molecular biology of stationary-phase E. coli cells has revealed interesting similarities to the aging process of higher organisms. The similarities include increased oxidation of cellular constituents and its target specificity, the role of antioxidants and oxygen tension in determining life span, and an apparent trade-off between activities related to reproduction and survival.
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Affiliation(s)
- Thomas Nyström
- Department of Cell and Molecular Biology, Microbiology, Göteborg University, Box 462, 405 30 Göteborg , Sweden.
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12
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Abstract
Analysis of senescent Escherichia coli cells reveals a link between protein oxidation and the fidelity of the translational apparatus. This model system has also provided a mechanistic molecular explanation for a trade-off between reproduction and survival activities, which may inspire proponents of the disposable soma theory and antagonistic pleiotropy hypothesis of aging.
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Affiliation(s)
- Thomas Nyström
- Department of Cell and Molecular Biology - Microbiology, Göteborg University Medicinaregatan 9C, Göteborg, Sweden.
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Ballesteros M, Fredriksson Å, Henriksson J, Nyström T. Bacterial senescence: protein oxidation in non-proliferating cells is dictated by the accuracy of the ribosomes. EMBO J 2001; 20:5280-9. [PMID: 11566891 PMCID: PMC125621 DOI: 10.1093/emboj/20.18.5280] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We have investigated the causal factors behind the age-related oxidation of proteins during arrest of cell proliferation. A proteomic approach demonstrated that protein oxidation in non-proliferating cells is observed primarily for proteins being produced in a number of aberrant isoforms. Also, these cells exhibited a reduced translational fidelity as demonstrated by both proteomic analysis and genetic measurements of nonsense suppression. Mutants harboring hyperaccurate ribosomes exhibited a drastically attenuated protein oxidation during growth arrest. In contrast, oxidation was augmented in mutants with error-prone ribosomes. Oxidation increased concomitantly with a reduced rate of translation, indicating that the production of aberrant, and oxidized proteins, is not the result of titration of the co-translational folding machinery. The age-related accumulation of the chaperones, DnaK and GroEL, was drastically attenuated in the hyperaccurate rpsL mutant, demonstrating that the reduced translational fidelity in growth-arrested cells may also be a primary cause for the induction of the heat shock regulon. The data point to an alternative way of approaching the causal factors involved in protein oxidation in eukaryotic G(0) cells.
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Affiliation(s)
| | | | | | - Thomas Nyström
- Department of Cell and Molecular Biology–Microbiology, Göteborg University, Medicinaregatan 9C, 413 90 Göteborg, Sweden
Corresponding author e-mail:
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Affiliation(s)
- R Holliday
- CSIRO Molecular Science, PO Box 184, North Ryde, Sydney, NSW 2113, Australia.
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15
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Abstract
Cancers increase during aging in mammals, and an accumulating body of evidence suggests that mutational events too do likewise. Mutational events are intimately involved in the malignant process. One current view is that mutator phenotypes are required in malignant cells for a sufficient number of critical target genes to be affected. These mutator phenotypes are believed to result from underlying deficiencies in genes necessary to maintain genomic stability. This review will provide a framework for a discussion of cancer and aging by detailing with a pair of wise approach studies that address the relations between aging, cancer, and mutations. Results from these studies will be used to suggest that a mutator phenotype develops in the cells of older individuals in the absence of an underlying genetic deficiency. Instead, it is proposed that a mixture of chromosomal aberrations, DNA damage, and chronic exposure to genotoxic forces, including oxidative stress, provide the basis for this age-accelerated mutator phenotype.
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Affiliation(s)
- M S Turker
- Center for Research on Occupational and Environmental Toxicology, L606, Oregon Health Sciences University, 3181 S.W. Sam Jackson Park Road, Portland, OR 97201, USA.
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16
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Abstract
A highly selective, eclectic, and personal view of new directions and new opportunities for research on the biology of aging is briefly outlined. Some concern is raised regarding the present emphasis on the use of centenarians for the definition of genetic loci responsible for unusually robust retention of structure and function. More progress is likely to be made were we to focus on the genetic basis for "elite" aging in middle-aged subjects examined for very specific phenotypes, as these are likely to be far less polygenic. Descriptive gerontology is entering a renaissance, given such new clinical tools as functional MRI and basic science tools such as functional genomics and proteomics. Advances in genomics should expedite answers to such questions as why some avian species have exceptionally long lifespans despite unusual loads of oxidative stress. One hopes to see renewed mechanistic studies, using such tools, at the systems levels. New methodologies are permitting the evaluation of stochastic alterations in gene structure and function in postreplicative cells. The exciting work on molecular misreading should prompt us to reexplore the Orgel hypothesis as it applies to such cell types. Epigenetic shifts in gene expression that occur in association with sexual maturation and the cessation of growth may have deleterious consequences late in the life course. It will therefore be important for gerontologists to investigate the molecular biology of pubescence. Finally, our community should investigate the impact of environmental "gerontogens," agents that accelerate specific processes of aging and specific senescent phenotypes.
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Affiliation(s)
- G M Martin
- Department of Pathology and Genetics, University of Washington, Seattle 98195, USA.
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18
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The error catastrophe theory of aging point counterpoint. Exp Gerontol 1997. [DOI: 10.1016/s0531-5565(97)00002-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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