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Emerson FJ, Lee SS. Chromatin: the old and young of it. Front Mol Biosci 2023; 10:1270285. [PMID: 37877123 PMCID: PMC10591336 DOI: 10.3389/fmolb.2023.1270285] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 09/20/2023] [Indexed: 10/26/2023] Open
Abstract
Aging affects nearly all aspects of our cells, from our DNA to our proteins to how our cells handle stress and communicate with each other. Age-related chromatin changes are of particular interest because chromatin can dynamically respond to the cellular and organismal environment, and many modifications at chromatin are reversible. Changes at chromatin occur during aging, and evidence from model organisms suggests that chromatin factors could play a role in modulating the aging process itself, as altering proteins that work at chromatin often affect the lifespan of yeast, worms, flies, and mice. The field of chromatin and aging is rapidly expanding, and high-resolution genomics tools make it possible to survey the chromatin environment or track chromatin factors implicated in longevity with precision that was not previously possible. In this review, we discuss the state of chromatin and aging research. We include examples from yeast, Drosophila, mice, and humans, but we particularly focus on the commonly used aging model, the worm Caenorhabditis elegans, in which there are many examples of chromatin factors that modulate longevity. We include evidence of both age-related changes to chromatin and evidence of specific chromatin factors linked to longevity in core histones, nuclear architecture, chromatin remodeling, and histone modifications.
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Affiliation(s)
| | - Siu Sylvia Lee
- Lee Lab, Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, United States
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Fan Q, Li XM, Zhai C, Li B, Li ST, Dong MQ. Somatic nuclear blebbing in Caenorhabditis elegans is not a feature of organismal aging but a potential indicator of germline proliferation in early adulthood. G3 (BETHESDA, MD.) 2023; 13:jkad029. [PMID: 36735812 PMCID: PMC10085788 DOI: 10.1093/g3journal/jkad029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 01/26/2023] [Accepted: 01/27/2023] [Indexed: 02/05/2023]
Abstract
Abnormal nuclear morphology is suggested to be a hallmark of aging and one such abnormality is nuclear blebbing. However, little is known about whether and how nuclear blebbing participates in animal aging, and what regulates it. In this study, we show that the frequency of nuclear blebbing in the hypodermis increases during aging in wild-type C. elegans. These nuclear blebs are enveloped by the nuclear lamina, the inner and the outer nuclear membrane, and 42% of them contain chromatin. Although nuclear blebbing could lead to DNA loss if chromatin-containing blebs detach and fuse with lysosomes, we find by time-lapse imaging that nuclear blebs rarely detach, and the estimated lifetime of a nuclear bleb is 772 h or 32 days. The amount of DNA lost through nuclear blebbing is estimated to be about 0.1% of the total DNA loss by adult Day 11. Furthermore, the frequency of nuclear blebbing does not correlate with the rate of aging in C. elegans. Old age does not necessarily induce nuclear blebbing, neither does starvation, heat stress, or oxidative stress. Intriguingly, we find that proliferation of germ cells promotes nuclear blebbing.
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Affiliation(s)
- Qiang Fan
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Xue-Mei Li
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Chao Zhai
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Bin Li
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Shang-Tong Li
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
| | - Meng-Qiu Dong
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100730, China
- National Institute of Biological Sciences (NIBS), Beijing 102206, China
- Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing 102206, China
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Hagemann A, Altrogge PK, Kehrenberg MCA, Diehl D, Jung D, Weber L, Bachmann HS. Analyzing the postulated inhibitory effect of Manumycin A on farnesyltransferase. Front Chem 2022; 10:967947. [PMID: 36561140 PMCID: PMC9763582 DOI: 10.3389/fchem.2022.967947] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
Manumycin A is postulated to be a specific inhibitor against the farnesyltransferase (FTase) since this effect has been shown in 1993 for yeast FTase. Since then, plenty of studies investigated Manumycin A in human cells as well as in model organisms like Caenorhabditis elegans. Some studies pointed to additional targets and pathways involved in Manumycin A effects like apoptosis. Therefore, these studies created doubt whether the main mechanism of action of Manumycin A is FTase inhibition. For some of these alternative targets half maximal inhibitory concentrations (IC50) of Manumycin A are available, but not for human and C. elegans FTase. So, we aimed to 1) characterize missing C. elegans FTase kinetics, 2) elucidate the IC50 and Ki values of Manumycin A on purified human and C. elegans FTase 3) investigate Manumycin A dependent expression of FTase and apoptosis genes in C. elegans. C. elegans FTase has its temperature optimum at 40°C with KM of 1.3 µM (farnesylpyrophosphate) and 1.7 µM (protein derivate). Whilst other targets are inhibitable by Manumycin A at the nanomolar level, we found that Manumycin A inhibits cell-free FTase in micromolar concentrations (Ki human 4.15 μM; Ki C. elegans 3.16 μM). Furthermore, our gene expression results correlate with other studies indicating that thioredoxin reductase 1 is the main target of Manumycin A. According to our results, the ability of Manumycin A to inhibit the FTase at the micromolar level is rather neglectable for its cellular effects, so we postulate that the classification as a specific FTase inhibitor is no longer valid.
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Charar C, Metsuyanim-Cohen S, Gruenbaum Y, Bar DZ. Exploring the nuclear lamina in health and pathology using C. elegans. Curr Top Dev Biol 2021; 144:91-110. [PMID: 33992162 DOI: 10.1016/bs.ctdb.2020.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The eukaryotic genome inside the nucleus is enveloped by two membranes, the Outer Nuclear Membrane (ONM) and the Inner Nuclear Membrane (INM). Tethered to the INM is the nuclear lamina, a fibrillar network composed of lamins-the nuclear intermediate filaments, and membrane associated proteins. The nuclear lamina interacts with several nuclear structures, including chromatin. As most nuclear functions, including regulation of gene expression, chromosome segregation and duplication as well as nuclear structure, are highly conserved in metazoans, the Caenorhabditis elegans nematode serves as a powerful model organism to study nuclear processes and architecture. This translucent organism can easily be observed under a microscope as a live embryo, larvae and even adult. Here we will review the data on nuclear lamina composition and functions gathered from studies using C. elegans model organisms: We will discuss genome spatial organization and its contribution to gene expression. We will review both the interaction between the cytoplasm and the nucleus and mechanotransduction mechanism. Finally, we will discuss disease causing mutation in nuclear lamins, including the use of this animal model in diseases research.
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Affiliation(s)
- Chayki Charar
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel; Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sally Metsuyanim-Cohen
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yosef Gruenbaum
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Daniel Z Bar
- Department of Oral Biology, The Goldschleger School of Dental Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
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Levine A, Grushko D, Cohen E. Gene expression modulation by the linker of nucleoskeleton and cytoskeleton complex contributes to proteostasis. Aging Cell 2019; 18:e13047. [PMID: 31576648 PMCID: PMC6826161 DOI: 10.1111/acel.13047] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/19/2019] [Accepted: 09/08/2019] [Indexed: 01/08/2023] Open
Abstract
Cellular mechanisms that act in concert to maintain protein homeostasis (proteostasis) are vital for organismal functionality and survival. Nevertheless, subsets of aggregation-prone proteins form toxic aggregates (proteotoxicity) that in some cases, underlie the development of neurodegenerative diseases. Proteotoxic aggregates are often deposited in the vicinity of the nucleus, a process that is cytoskeleton-dependent. Accordingly, cytoskeletal dysfunction contributes to pathological hallmarks of various neurodegenerative diseases. Here, we asked whether the linker of nucleoskeleton and cytoskeleton (LINC) complex, which bridges these filaments across the nuclear envelope, is needed for the maintenance of proteostasis. Employing model nematodes, we discovered that knocking down LINC components impairs the ability of the worm to cope with proteotoxicity. Knocking down anc-1, which encodes a key component of the LINC complex, modulates the expression of transcription factors and E3 ubiquitin ligases, thereby affecting the rates of protein ubiquitination and impairing proteasome-mediated protein degradation. Our results establish a link between the LINC complex, protein degradation, and neurodegeneration-associated proteotoxicity.
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Affiliation(s)
- Amir Levine
- Department of Biochemistry and Molecular Biology The Institute for Medical Research Israel‐Canada The Hebrew University of Jerusalem Jerusalem Israel
| | - Danielle Grushko
- Department of Biochemistry and Molecular Biology The Institute for Medical Research Israel‐Canada The Hebrew University of Jerusalem Jerusalem Israel
| | - Ehud Cohen
- Department of Biochemistry and Molecular Biology The Institute for Medical Research Israel‐Canada The Hebrew University of Jerusalem Jerusalem Israel
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Abstract
Lamins are evolutionarily conserved nuclear intermediate filament proteins. They provide structural support for the nucleus and help regulate many other nuclear activities. Mutations in human lamin genes, and especially in the LMNA gene, cause numerous diseases, termed laminopathies, including muscle, cardiac, metabolic, neuronal and early aging diseases. Most laminopathies arise from autosomal dominant missense mutations. Many of the mutant residues are conserved in the lamin genes of the nematode Caenorhabditis elegans and the fruit fly Drosophila melanogaster. Our current understanding of the mechanisms leading to these diseases is mostly based on patients cell lines and animal models including C. elegans and D. melanogaster. The simpler lamin system and the powerful genetic tools offered by these invertebrate organisms greatly contributed to such studies. Here we provide an overview of the studies of laminopathies in Drosophila and C. elegans models.
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Affiliation(s)
- Ryszard Rzepecki
- a Laboratory of Nuclear Proteins, Faculty of Biotechnology , University of Wroclaw , Fryderyka Joliot-Curie, Wroclaw , Poland
| | - Yosef Gruenbaum
- a Laboratory of Nuclear Proteins, Faculty of Biotechnology , University of Wroclaw , Fryderyka Joliot-Curie, Wroclaw , Poland.,b Department of Genetics , Institute of Life Sciences, Hebrew University of Jerusalem , Jerusalem , Israel
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Zhao M, An J, Li H, Zhang J, Li ST, Li XM, Dong MQ, Mao H, Tao L. Segmentation and classification of two-channel C. elegans nucleus-labeled fluorescence images. BMC Bioinformatics 2017; 18:412. [PMID: 28915791 PMCID: PMC5602880 DOI: 10.1186/s12859-017-1817-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 09/06/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Aging is characterized by a gradual breakdown of cellular structures. Nuclear abnormality is a hallmark of progeria in human. Analysis of age-dependent nuclear morphological changes in Caenorhabditis elegans is of great value to aging research, and this calls for an automatic image processing method that is suitable for both normal and abnormal structures. RESULTS Our image processing method consists of nuclear segmentation, feature extraction and classification. First, taking up the challenges of defining individual nuclei with fuzzy boundaries or in a clump, we developed an accurate nuclear segmentation method using fused two-channel images with seed-based cluster splitting and k-means algorithm, and achieved a high precision against the manual segmentation results. Next, we extracted three groups of nuclear features, among which five features were selected by minimum Redundancy Maximum Relevance (mRMR) for classifiers. After comparing the classification performances of several popular techniques, we identified that Random Forest, which achieved a mean class accuracy (MCA) of 98.69%, was the best classifier for our data set. Lastly, we demonstrated the method with two quantitative analyses of C. elegans nuclei, which led to the discovery of two possible longevity indicators. CONCLUSIONS We produced an automatic image processing method for two-channel C. elegans nucleus-labeled fluorescence images. It frees biologists from segmenting and classifying the nuclei manually.
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Affiliation(s)
- Mengdi Zhao
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Jie An
- LMAM, School of Mathematical Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Haiwen Li
- LMAM, School of Mathematical Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Jiazhi Zhang
- Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China
| | - Shang-Tong Li
- National Institute of Biological Sciences, Beijing, Kexueyuan Road, Beijing, 102206, China
| | - Xue-Mei Li
- National Institute of Biological Sciences, Beijing, Kexueyuan Road, Beijing, 102206, China
| | - Meng-Qiu Dong
- National Institute of Biological Sciences, Beijing, Kexueyuan Road, Beijing, 102206, China
| | - Heng Mao
- LMAM, School of Mathematical Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China.
| | - Louis Tao
- Center for Quantitative Biology, Academy for Advanced Interdisciplinary Studies, Peking University, Yiheyuan Road, Beijing, 100871, China. .,Center for Bioinformatics, National Laboratory of Protein Engineering and Plant Genetic Engineering, School of Life Sciences, Peking University, Yiheyuan Road, Beijing, 100871, China.
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Cohen-Fix O, Askjaer P. Cell Biology of the Caenorhabditis elegans Nucleus. Genetics 2017; 205:25-59. [PMID: 28049702 PMCID: PMC5216270 DOI: 10.1534/genetics.116.197160] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/09/2016] [Indexed: 12/25/2022] Open
Abstract
Studies on the Caenorhabditis elegans nucleus have provided fascinating insight to the organization and activities of eukaryotic cells. Being the organelle that holds the genetic blueprint of the cell, the nucleus is critical for basically every aspect of cell biology. The stereotypical development of C. elegans from a one cell-stage embryo to a fertile hermaphrodite with 959 somatic nuclei has allowed the identification of mutants with specific alterations in gene expression programs, nuclear morphology, or nuclear positioning. Moreover, the early C. elegans embryo is an excellent model to dissect the mitotic processes of nuclear disassembly and reformation with high spatiotemporal resolution. We review here several features of the C. elegans nucleus, including its composition, structure, and dynamics. We also discuss the spatial organization of chromatin and regulation of gene expression and how this depends on tight control of nucleocytoplasmic transport. Finally, the extensive connections of the nucleus with the cytoskeleton and their implications during development are described. Most processes of the C. elegans nucleus are evolutionarily conserved, highlighting the relevance of this powerful and versatile model organism to human biology.
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Affiliation(s)
- Orna Cohen-Fix
- Laboratory of Molecular and Cellular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Peter Askjaer
- Andalusian Center for Developmental Biology, Consejo Superior de Investigaciones Científicas/Junta de Andalucia/Universidad Pablo de Olavide, 41013 Seville, Spain
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Zuela N, Zwerger M, Levin T, Medalia O, Gruenbaum Y. Impaired mechanical response of an EDMD mutation leads to motility phenotypes that are repaired by loss of prenylation. J Cell Sci 2016; 129:1781-91. [PMID: 27034135 DOI: 10.1242/jcs.184309] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/21/2016] [Indexed: 12/20/2022] Open
Abstract
There are roughly 14 distinct heritable autosomal dominant diseases associated with mutations in lamins A/C, including Emery-Dreifuss muscular dystrophy (EDMD). The mechanical model proposes that the lamin mutations change the mechanical properties of muscle nuclei, leading to cell death and tissue deterioration. Here, we developed an experimental protocol that analyzes the effect of disease-linked lamin mutations on the response of nuclei to mechanical strain in living Caenorhabditis elegans We found that the EDMD mutation L535P disrupts the nuclear mechanical response specifically in muscle nuclei. Inhibiting lamin prenylation rescued the mechanical response of the EDMD nuclei, reversed the muscle phenotypes and led to normal motility. The LINC complex and emerin were also required to regulate the mechanical response of C. elegans nuclei. This study provides evidence to support the mechanical model and offers a potential future therapeutic approach towards curing EDMD.
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Affiliation(s)
- Noam Zuela
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Monika Zwerger
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland
| | - Tal Levin
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Ohad Medalia
- Department of Biochemistry, University of Zurich, Winterthurerstrasse 190, Zurich 8057, Switzerland Department of Life Sciences and the National Institute for Biotechnology in the Negev, Ben-Gurion University, Beer-Sheva 84105, Israel
| | - Yosef Gruenbaum
- Department of Genetics, Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem 91904, Israel
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Scharf DH, Brakhage AA, Mukherjee PK. Gliotoxin--bane or boon? Environ Microbiol 2015; 18:1096-109. [PMID: 26443473 DOI: 10.1111/1462-2920.13080] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/30/2015] [Accepted: 10/04/2015] [Indexed: 12/31/2022]
Abstract
Gliotoxin (GT) is the most important epidithiodioxopiperazine (ETP)-type fungal toxin. GT was originally isolated from Trichoderma species as an antibiotic substance involved in biological control of plant pathogenic fungi. A few isolates of GT-producing Trichoderma virens are commercially marketed for biological control and widely used in agriculture. Furthermore, GT is long known as an immunosuppressive agent and also reported to have anti-tumour properties. However, recent publications suggest that GT is a virulence determinant of the human pathogen Aspergillus fumigatus. This compound is thus important on several counts - it has medicinal properties, is a pathogenicity determinant, is a potential diagnostic marker and is important in biological crop protection. The present article addresses this paradox and the ecological role of GT. We discuss the function of GT as defence molecule, the role in aspergillosis and suggest solutions for safe application of Trichoderma-based biofungicides.
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Affiliation(s)
- Daniel H Scharf
- Department of Molecular and Applied Microbiology, Leibniz-Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI) and Institute for Microbiology, Friedrich Schiller University Jena, Beutenbergstr. 11a, 07745, Jena, Germany
| | - Axel A Brakhage
- Department of Molecular and Applied Microbiology, Leibniz-Institute for Natural Product Research and Infection Biology, Hans Knoell Institute (HKI) and Institute for Microbiology, Friedrich Schiller University Jena, Beutenbergstr. 11a, 07745, Jena, Germany
| | - Prasun K Mukherjee
- Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085, India
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Pérez-Jiménez MM, Rodríguez-Palero MJ, Ródenas E, Askjaer P, Muñoz MJ. Age-dependent changes of nuclear morphology are uncoupled from longevity in Caenorhabditis elegans IGF/insulin receptor daf-2 mutants. Biogerontology 2014; 15:279-88. [DOI: 10.1007/s10522-014-9497-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 03/14/2014] [Indexed: 01/10/2023]
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Stochaj U, Kodiha M, Shum-Tim D, Colmegna I. Implications of multipotent mesenchymal stromal cell aging. Regen Med 2013; 8:211-22. [PMID: 23477400 DOI: 10.2217/rme.13.10] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Aging is defined as the progressive and generalized impairment of function, resulting in an increasing vulnerability to environmental challenges and a growing risk of disease and death. The decline in the regenerative capacity of resident stem cells across different tissues is a central mediator of aging. In this paper we review the evidence implicating multipotent mesenchymal stromal cells as being subject to and causes of tissue and organismal aging. We specifically discuss the nuclear changes that occur in the context of Hutchinson-Gilford progeria syndrome, a premature aging syndrome that preferentially affects tissues of mesenchymal origin.
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Affiliation(s)
- Ursula Stochaj
- Department of Physiology, McGill University, McIntyre Medical Sciences Building, Room 1115, 3655 Promenade Sir William Osler, Montréal, Québec H3G 1Y6, Canada
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Rauthan M, Pilon M. The mevalonate pathway in C. elegans. Lipids Health Dis 2011; 10:243. [PMID: 22204706 PMCID: PMC3274489 DOI: 10.1186/1476-511x-10-243] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 12/28/2011] [Indexed: 11/10/2022] Open
Abstract
The mevalonate pathway in human is responsible for the synthesis of cholesterol and other important biomolecules such as coenzyme Q, dolichols and isoprenoids. These molecules are required in the cell for functions ranging from signaling to membrane integrity, protein prenylation and glycosylation, and energy homeostasis. The pathway consists of a main trunk followed by sub-branches that synthesize the different biomolecules. The majority of our knowledge about the mevalonate pathway is currently focused on the cholesterol synthesis branch, which is the target of the cholesterol-lowering statins; less is known about the function and regulation of the non-cholesterol-related branches. To study them, we need a biological system where it is possible to specifically modulate these metabolic branches individually or in groups. The nematode Caenorhabditis elegans (C. elegans) is a promising model to study these non-cholesterol branches since its mevalonate pathway seems very well conserved with that in human except that it has no cholesterol synthesis branch. The simple genetic makeup and tractability of C. elegans makes it relatively easy to identify and manipulate key genetic components of the mevalonate pathway, and to evaluate the consequences of tampering with their activity. This general experimental approach should lead to new insights into the physiological roles of the non-cholesterol part of the mevalonate pathway. This review will focus on the current knowledge related to the mevalonate pathway in C. elegans and its possible applications as a model organism to study the non-cholesterol functions of this pathway.
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Affiliation(s)
- Manish Rauthan
- Department of Cell and Molecular Biology, University of Gothenburg, S-405 30 Gothenburg, Sweden
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Abstract
Progeroid laminopathies are characterized by the abnormal processing of lamin A, the appearance of misshapen nuclei, and the accumulation and persistence of DNA damage. In the present article, I consider the contribution of defective DNA damage pathways to the pathology of progeroid laminopathies. Defects in DNA repair pathways appear to be caused by a combination of factors. These include abnormal epigenetic modifications of chromatin that are required to recruit DNA repair pathways to sites of DNA damage, abnormal recruitment of DNA excision repair proteins to sites of DNA double-strand breaks, and unrepairable ROS (reactive oxygen species)-induced DNA damage. At least two of these defective processes offer the potential for novel therapeutic approaches.
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Richards SA, Muter J, Ritchie P, Lattanzi G, Hutchison CJ. The accumulation of un-repairable DNA damage in laminopathy progeria fibroblasts is caused by ROS generation and is prevented by treatment with N-acetyl cysteine. Hum Mol Genet 2011; 20:3997-4004. [PMID: 21807766 DOI: 10.1093/hmg/ddr327] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Fibroblasts from patients with the severe laminopathy diseases, restrictive dermopathy (RD) and Hutchinson Gilford progeria syndrome (HGPS), are characterized by poor growth in culture, the presence of abnormally shaped nuclei and the accumulation of DNA double-strand breaks (DSB). Here we show that the accumulation of DSB and poor growth of the fibroblasts but not the presence of abnormally shaped nuclei are caused by elevated levels of reactive oxygen species (ROS) and greater sensitivity to oxidative stress. Basal levels of ROS and sensitivity to H(2)O(2) were compared in fibroblasts from normal, RD and HGPS individuals using fluorescence activated cell sorting-based assays. Basal levels of ROS and stimulated levels of ROS were both 5-fold higher in the progeria fibroblasts. Elevated levels of ROS were correlated with lower proliferation indices but not with the presence of abnormally shaped nuclei. DSB induced by etoposide were repaired efficiently in normal, RD and HGPS fibroblasts. In contrast, DSB induced by ROS were repaired efficiently in normal fibroblasts, but in RD and HGPS fibroblasts many ROS-induced DSB were un-repairable. The accumulation of ROS-induced DSB appeared to cause the poor growth of RD and HGPS fibroblasts, since culture in the presence of the ROS scavenger N-acetyl cysteine (NAC) reduced the basal levels of DSB, eliminated un-repairable ROS-induced DSB and greatly improved population-doubling times. Our findings suggest that un-repaired ROS-induced DSB contribute significantly to the RD and HGPS phenotypes and that inclusion of NAC in a combinatorial therapy might prove beneficial to HGPS patients.
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Affiliation(s)
- Shane A Richards
- The School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE,UK
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