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Hemagirri M, Chen Y, Gopinath SCB, Sahreen S, Adnan M, Sasidharan S. Crosstalk between protein misfolding and endoplasmic reticulum stress during ageing and their role in age-related disorders. Biochimie 2024; 221:159-181. [PMID: 37918463 DOI: 10.1016/j.biochi.2023.10.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 10/25/2023] [Accepted: 10/30/2023] [Indexed: 11/04/2023]
Abstract
Maintaining the proteome is crucial to retaining cell functionality and response to multiple intrinsic and extrinsic stressors. Protein misfolding increased the endoplasmic reticulum (ER) stress and activated the adaptive unfolded protein response (UPR) to restore cell homeostasis. Apoptosis occurs when ER stress is prolonged or the adaptive response fails. In healthy young cells, the ratio of protein folding machinery to quantities of misfolded proteins is balanced under normal circumstances. However, the age-related deterioration of the complex systems for handling protein misfolding is accompanied by ageing-related disruption of protein homeostasis, which results in the build-up of misfolded and aggregated proteins. This ultimately results in decreased cell viability and forms the basis of common age-related diseases called protein misfolding diseases. Proteins or protein fragments convert from their ordinarily soluble forms to insoluble fibrils or plaques in many of these disorders, which build up in various organs such as the liver, brain, or spleen. Alzheimer's, Parkinson's, type II diabetes, and cancer are diseases in this group commonly manifest in later life. Thus, protein misfolding and its prevention by chaperones and different degradation paths are becoming understood from molecular perspectives. Proteodynamics information will likely affect future interventional techniques to combat cellular stress and support healthy ageing by avoiding and treating protein conformational disorders. This review provides an overview of the diverse proteostasis machinery, protein misfolding, and ER stress involvement, which activates the UPR sensors. Here, we will discuss the crosstalk between protein misfolding and ER stress and their role in developing age-related diseases.
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Affiliation(s)
- Manisekaran Hemagirri
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, USM, 11800, Pulau Pinang, Malaysia
| | - Yeng Chen
- Department of Oral & Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, 50603, Malaysia
| | - Subash C B Gopinath
- Faculty of Chemical Engineering and Technology, Universiti Malaysia Perlis, Arau, 02600, Malaysia
| | - Sumaira Sahreen
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, USM, 11800, Pulau Pinang, Malaysia
| | - Mohd Adnan
- Department of Biology, College of Science, University of Ha'il, Ha'il, P. O. Box 2440, Saudi Arabia.
| | - Sreenivasan Sasidharan
- Institute for Research in Molecular Medicine (INFORMM), Universiti Sains Malaysia, USM, 11800, Pulau Pinang, Malaysia.
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Sonowal R, Swimm A, Sahoo A, Luo L, Matsunaga Y, Wu Z, Bhingarde JA, Ejzak EA, Ranawade A, Qadota H, Powell DN, Capaldo CT, Flacker JM, Jones RM, Benian GM, Kalman D. Indoles from commensal bacteria extend healthspan. Proc Natl Acad Sci U S A 2017; 114:E7506-E7515. [PMID: 28827345 PMCID: PMC5594673 DOI: 10.1073/pnas.1706464114] [Citation(s) in RCA: 123] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Multiple studies have identified conserved genetic pathways and small molecules associated with extension of lifespan in diverse organisms. However, extending lifespan does not result in concomitant extension in healthspan, defined as the proportion of time that an animal remains healthy and free of age-related infirmities. Rather, mutations that extend lifespan often reduce healthspan and increase frailty. The question arises as to whether factors or mechanisms exist that uncouple these processes and extend healthspan and reduce frailty independent of lifespan. We show that indoles from commensal microbiota extend healthspan of diverse organisms, including Caenorhabditis elegans, Drosophila melanogaster, and mice, but have a negligible effect on maximal lifespan. Effects of indoles on healthspan in worms and flies depend upon the aryl hydrocarbon receptor (AHR), a conserved detector of xenobiotic small molecules. In C. elegans, indole induces a gene expression profile in aged animals reminiscent of that seen in the young, but which is distinct from that associated with normal aging. Moreover, in older animals, indole induces genes associated with oogenesis and, accordingly, extends fecundity and reproductive span. Together, these data suggest that small molecules related to indole and derived from commensal microbiota act in diverse phyla via conserved molecular pathways to promote healthy aging. These data raise the possibility of developing therapeutics based on microbiota-derived indole or its derivatives to extend healthspan and reduce frailty in humans.
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Affiliation(s)
- Robert Sonowal
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Alyson Swimm
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Anusmita Sahoo
- Emory Vaccine Center, Emory University, Atlanta, GA 30329
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322
- Yerkes National Primate Research Center, Lawrenceville, GA 30043
| | - Liping Luo
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
| | - Yohei Matsunaga
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Ziqi Wu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Jui A Bhingarde
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Elizabeth A Ejzak
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Ayush Ranawade
- Department of Biology, McMaster University, Hamilton, ON, Canada L8S 4K1
| | - Hiroshi Qadota
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Domonica N Powell
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
- Immunology and Molecular Pathogenesis Graduate Program, Emory University School of Medicine, Atlanta, GA 30322
| | | | - Jonathan M Flacker
- Division of Geriatric Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Rhienallt M Jones
- Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322
| | - Guy M Benian
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322
| | - Daniel Kalman
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, Atlanta, GA 30322;
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Li E, Wang S, Li C, Wang X, Chen K, Chen L. Transcriptome sequencing revealed the genes and pathways involved in salinity stress of Chinese mitten crab, Eriocheir sinensis. Physiol Genomics 2014; 46:177-90. [DOI: 10.1152/physiolgenomics.00191.2013] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A total of 276.9 million reads were obtained and assembled into 206, 371 contigs with an average length of 614 bp and N50 of 1,470 bp. Comparison of digital gene expression between treatment and control group reveals 1,151 and 941 genes were significantly differentially expressed in crab gill and muscle, respectively. In gill and muscle, protein ubiquitination, ubiquinone biosynthesis, oxidative phosphorylation, and mitochondria dysfunction pathways were the top pathways differentially expressed following the challenge. EIF 2 signaling pathway and IGF-1 signaling pathway were the top ones among the signal-related pathways. Most of the amino acid metabolism pathways were found to be involved in this process. The expression patterns of 15 differentially expressed genes were validated by quantitative real-time RT-PCR (average correlation coefficient 0.80). This is the first report of expression analysis of genes and pathways involved in osmoregulation of Eriocheir sinensis through transcriptome sequencing. The findings of this study will further promote the understanding of the underlying molecular mechanism of salinity stress adaptation for crustacean species.
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Affiliation(s)
- Erchao Li
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Shaolin Wang
- Department of Psychiatry & Neurobiology Science, University of Virginia, Charlottesville, Virginia; and
| | - Chao Li
- School of Fisheries, Aquaculture and Aquatic Sciences, Auburn University, Auburn, Alabama
| | - Xiaodan Wang
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Ke Chen
- School of Life Sciences, East China Normal University, Shanghai, China
| | - Liqiao Chen
- School of Life Sciences, East China Normal University, Shanghai, China
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Dimethyl sulfoxide and dimethyl formamide increase lifespan of C. elegans in liquid. Mech Ageing Dev 2013; 134:69-78. [DOI: 10.1016/j.mad.2012.10.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 10/16/2012] [Accepted: 10/26/2012] [Indexed: 11/21/2022]
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Lucanic M, Lithgow GJ, Alavez S. Pharmacological lifespan extension of invertebrates. Ageing Res Rev 2013; 12:445-58. [PMID: 22771382 DOI: 10.1016/j.arr.2012.06.006] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Revised: 06/28/2012] [Accepted: 06/29/2012] [Indexed: 01/11/2023]
Abstract
There is considerable interest in identifying small, drug-like compounds that slow aging in multiple species, particularly in mammals. Such compounds may prove to be useful in treating and retarding age-related disease in humans. Just as invertebrate models have been essential in helping us understand the genetic pathways that control aging, these model organisms are also proving valuable in discovering chemical compounds that influence longevity. The nematode Caenorhabditis elegans has numerous advantages for such studies including its short lifespan and has been exploited by a number of investigators to find compounds that impact aging. Here, we summarize the progress being made in identifying compounds that extend the lifespan of invertebrates, and introduce the challenges we face in translating this research into human therapies.
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Koga H, Kaushik S, Cuervo AM. Protein homeostasis and aging: The importance of exquisite quality control. Ageing Res Rev 2011; 10:205-15. [PMID: 20152936 DOI: 10.1016/j.arr.2010.02.001] [Citation(s) in RCA: 307] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 01/25/2010] [Accepted: 02/01/2010] [Indexed: 01/12/2023]
Abstract
All cells count on precise mechanisms that regulate protein homeostasis to maintain a stable and functional proteome. A progressive deterioration in the ability of cells to preserve the stability of their proteome occurs with age and contributes to the functional loss characteristic of old organisms. Molecular chaperones and the proteolytic systems are responsible for this cellular quality control by assuring continuous renewal of intracellular proteins. When protein damage occurs, such as during cellular stress, the coordinated action of these cellular surveillance systems allows detection and repair of the damaged structures or, in many instances, leads to the complete elimination of the altered proteins from inside cells. Dysfunction of the quality control mechanisms and intracellular accumulation of abnormal proteins in the form of protein inclusions and aggregates occur in almost all tissues of an aged organism. Preservation or enhancement of the activity of these surveillance systems until late in life improves their resistance to stress and is sufficient to slow down aging. In this work, we review recent advances on our understanding of the contribution of chaperones and proteolytic systems to the maintenance of cellular homeostasis, the cellular response to stress and ultimately to longevity.
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Affiliation(s)
- Hiroshi Koga
- Department of Developmental and Molecular Biology, Marion Bessin Liver Research Center, Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Hyun M, Lee J, Lee K, May A, Bohr VA, Ahn B. Longevity and resistance to stress correlate with DNA repair capacity in Caenorhabditis elegans. Nucleic Acids Res 2008; 36:1380-9. [PMID: 18203746 PMCID: PMC2275101 DOI: 10.1093/nar/gkm1161] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
DNA repair is an important mechanism by which cells maintain genomic integrity. Decline in DNA repair capacity or defects in repair factors are thought to contribute to premature aging in mammals. The nematode Caenorhabditis elegans is a good model for studying longevity and DNA repair because of key advances in understanding the genetics of aging in this organism. Long-lived C. elegans mutants have been identified and shown to be resistant to oxidizing agents and UV irradiation, suggesting a genetically determined correlation between DNA repair capacity and life span. In this report, gene-specific DNA repair is compared in wild-type C. elegans and stress-resistant C. elegans mutants for the first time. DNA repair capacity is higher in long-lived C. elegans mutants than in wild-type animals. In addition, RNAi knockdown of the nucleotide excision repair gene xpa-1 increased sensitivity to UV and reduced the life span of long-lived C. elegans mutants. These findings support that DNA repair capacity correlates with longevity in C. elegans.
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Affiliation(s)
- Moonjung Hyun
- Department of Life Sciences, University of Ulsan 680-749, Korea
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Jiang H, Talaska AE, Schacht J, Sha SH. Oxidative imbalance in the aging inner ear. Neurobiol Aging 2007; 28:1605-12. [PMID: 16920227 PMCID: PMC2453750 DOI: 10.1016/j.neurobiolaging.2006.06.025] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 05/11/2006] [Accepted: 06/22/2006] [Indexed: 01/08/2023]
Abstract
The mammalian inner ear loses its sensory cells with advancing age, accompanied by a functional decrease in balance and hearing. This study investigates oxidant stress in the cochlea of aging male CBA/J mice. Glutathione-conjugated proteins, markers of H2O2-mediated oxidation, began to increase at 12 months of age; 4-hydroxynonenal and 3-nitrotyrosine, products of hydroxyl radical and peroxynitrite action, respectively, were elevated by 18 months. Immunoreactivity to these markers was stronger in the supporting cells (Deiters and pillar cells) than the sensory cells and appeared later (23 months) in spiral ganglion cells and in the stria vascularis and spiral ligament. Conversely, antioxidant proteins (AIF) and enzymes (SOD2) decreased by 18 months in the organ of Corti (including the sensory cells) and spiral ganglion cells but not in the stria vascularis. These results suggest the presence of different reactive oxygen species and differential time courses of oxidative changes in individual tissues of the aging cochlea. An imbalance of redox status may be a component of age-related hearing loss.
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Affiliation(s)
| | - Andra E. Talaska
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI 48109-0506, USA
| | - Jochen Schacht
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI 48109-0506, USA
| | - Su-Hua Sha
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, Ann Arbor, MI 48109-0506, USA
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11
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Maynard SP, Miller RA. Fibroblasts from long-lived Snell dwarf mice are resistant to oxygen-induced in vitro growth arrest. Aging Cell 2006; 5:89-96. [PMID: 16441847 DOI: 10.1111/j.1474-9726.2006.00187.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Snell dwarf mice live longer than controls, and show lower age-adjusted rates of lethal neoplastic diseases. Fibroblast cells from adult dwarf mice are resistant to the lethal effects of oxidative and nonoxidative stresses, including the carcinogen methyl methanesulfonate. We now report that dwarf-derived fibroblasts are slow to enter the stage of growth arrest induced by culturing normal cells under standard culture conditions at 20% O(2). Dwarf cells cultured at 20% O(2) resemble control cells cultured at 3% O(2) not only in their delayed growth arrest, but also in their rapid growth rates and resistance to both oxidative and nonoxidative forms of cytotoxic stress. Levels of the heat-shock protein HSP-70 respond to serum withdrawal and stress only in control cells, showing that intracellular signals are blunted in dwarf-derived cells. These data suggest a model in which stable epigenetic changes induced in skin fibroblasts by the hormonal milieu of the Snell dwarf lead to resistance to multiple forms of injury, including the oxidative damage that contributes to growth arrest in vitro and neoplasia in intact mice.
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Affiliation(s)
- Scott P Maynard
- Department of Pathology and Geriatrics Center, University of Michigan, and Ann Arbor VA Medical Center, Ann Arbor, MI 48109-0940, USA
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12
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Lithgow GJ, Gill MS, Olsen A, Sampayo JN. Pharmacological intervention in invertebrate aging. AGE (DORDRECHT, NETHERLANDS) 2005; 27:213-23. [PMID: 23598654 PMCID: PMC3458493 DOI: 10.1007/s11357-005-3625-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2005] [Revised: 06/07/2005] [Accepted: 06/08/2005] [Indexed: 04/17/2023]
Affiliation(s)
| | - Matthew S. Gill
- The Buck Institute, 8001 Redwood Blvd., Novato, CA 94945 USA
| | - Anders Olsen
- The Buck Institute, 8001 Redwood Blvd., Novato, CA 94945 USA
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13
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Sampayo JN, Olsen A, Lithgow GJ. Oxidative stress in Caenorhabditis elegans: protective effects of superoxide dismutase/catalase mimetics. Aging Cell 2003; 2:319-26. [PMID: 14677634 DOI: 10.1046/j.1474-9728.2003.00063.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The lifespan of Caenorhabditis elegans can be extended by the administration of synthetic superoxide dismutase/ catalase mimetics (SCMs) without any effects on development or fertility. Here we demonstrate that the mimetics, Euk-134 and Euk-8, confer resistance to the oxidative stress-inducing agent, paraquat and to thermal stress. The protective effects of the compounds are apparent with treatments either during development or during adulthood and are independent of an insulin/IGF-I-like signalling pathway also known to affect thermal and oxidative stress resistance. Worms exposed to the compounds do not induce a cellular stress response and no detrimental effects are observed.
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Affiliation(s)
- James N Sampayo
- The Buck Institute, 8001 Redwood Boulevard, Novato, CA 94945, USA
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Arking R, Novoseltseva J, Hwangbo DS, Novoseltsev V, Lane M. Different age-specific demographic profiles are generated in the same normal-lived Drosophila strain by different longevity stimuli. J Gerontol A Biol Sci Med Sci 2002; 57:B390-8. [PMID: 12403794 DOI: 10.1093/gerona/57.11.b390] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We review the empirical data obtained with our normal-lived Ra control strain of Drosophila and show that this one genome is capable of invoking at least three different responses to external stimuli that induce the animal to express one of three different extended longevity phenotypes, each of which arises from one of three different antagonistic molecular mechanisms of stress resistance. The phenotypes are distinguished by different age-specific mortality patterns. Depending on the selected mechanism, the genome may respond by expressing a delayed onset of senescence (type 1), an increased early survival (type 2), or an increased late survival (type 3) phenotype, suggesting their different demographic effects. We suggest that the different demographic effects stem in part from the differential ability of each selection regime to reallocate the organism's energy from reproduction to somatic maintenance. These data document the complexity of the aging process and argue for a relationship between molecular mechanisms and longevity phenotypes.
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Affiliation(s)
- Robert Arking
- Department of Biological Sciences, Wayne State University, Detroit, Michigan 48202, USA.
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Abstract
The insulin/IGF-1 (where IGF-1 is insulin-like growth factor-1) signaling pathway influences longevity, reproduction, and diapause in many organisms. Because of the fundamental importance of this system in animal physiology, we asked when during the animal's life it is required to regulate these different processes. We find that in Caenorhabditis elegans, the pathway acts during adulthood, to relatively advanced ages, to influence aging. In contrast, it regulates diapause during development. In addition, the pathway controls longevity and reproduction independently of one another. Together our findings show that life-span regulation can be dissociated temporally from phenotypes that might seem to decrease the quality of life.
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Affiliation(s)
- Andrew Dillin
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94143-0448, USA
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Abstract
BACKGROUND Numerous gerontogene mutants leading to dramatic life extensions have been identified in the nematode Caenorhabditis elegans over the last 20 years. Analysis of these mutants has provided a basis for understanding the mechanisms driving the aging process(es). Several distinct mechanisms including an altered rate of aging, increased resistance to stress, decreased metabolic rate, or alterations in a program causing organismic aging and death have been proposed to underlie these mutants. RESULTS Whole-genome analysis of gene expression during chronological aging of the worm provides a rich database of age-specific changes in gene expression and represents one way to distinguish among these models. Using a rigorous statistical model with multiple replicates, we find that a relatively small number of genes (only 164) show statistically significant changes in transcript levels as aging occurs (<1% of the genome). Expression of heat shock proteins decreases, while expression of certain transposases increases in older worms, and these findings are consistent with a higher mortality risk due to a failure in homeostenosis and destabilization of the genome in older animals. Finally, a specific subset of genes is coordinately altered both during chronological aging and in the transition from the reproductive form to the dauer, demonstrating a mechanistic overlap in aging between these two processes. CONCLUSIONS We have performed a whole-genome analysis of changes in gene expression during aging in C. elegans that provides a molecular description of C. elegans senescence.
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Affiliation(s)
- James Lund
- Department of Developmental Biology, Stanford University Medical Center, Stanford, CA 94305, USA
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Feng J, Bussière F, Hekimi S. Mitochondrial electron transport is a key determinant of life span in Caenorhabditis elegans. Dev Cell 2001; 1:633-44. [PMID: 11709184 DOI: 10.1016/s1534-5807(01)00071-5] [Citation(s) in RCA: 481] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Increased protection from reactive oxygen species (ROS) is believed to increase life span. However, it has not been clearly demonstrated that endogenous ROS production actually limits normal life span. We have identified a mutation in the Caenorhabditis elegans iron sulfur protein (isp-1) of mitochondrial complex III, which results in low oxygen consumption, decreased sensitivity to ROS, and increased life span. Furthermore, combining isp-1(qm150) with a mutation (daf-2) that increases resistance to ROS does not result in any significant further increase in adult life span. These findings indicate that both isp-1 and daf-2 mutations increase life span by lowering oxidative stress and result in the maximum life span increase that can be produced in this way.
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Affiliation(s)
- J Feng
- Department of Biology, McGill University, 1205 Avenue Dr Penfield, H3A 1B1, Montréal, Québec, Canada
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Bénard C, McCright B, Zhang Y, Felkai S, Lakowski B, Hekimi S. TheC. elegansmaternal-effect geneclk-2is essential for embryonic development, encodes a protein homologous to yeast Tel2p and affects telomere length. Development 2001; 128:4045-55. [PMID: 11641227 DOI: 10.1242/dev.128.20.4045] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Caenorhabditis elegans maternal-effect clk genes are involved in the temporal control of development and behavior. We report the genetic and molecular characterization of clk-2. A temperature-sensitive mutation in the gene clk-2 affects embryonic and post-embryonic development, reproduction, and rhythmic behaviors. Yet, virtually all phenotypes are fully maternally rescued. Embryonic development strictly requires the activity of maternal clk-2 during a narrow time window between oocyte maturation and the two- to four-cell embryonic stage. Positional cloning of clk-2 reveals that it encodes a protein homologous to S. cerevisiae Tel2p. In yeast, the gene TEL2 regulates telomere length and participates in gene silencing at subtelomeric regions. In C. elegans, clk-2 mutants have elongated telomeres, and clk-2 overexpression can lead to telomere shortening. Tel2p has been reported to bind to telomeric DNA repeats in vitro. However, we find that a functional CLK-2::GFP fusion protein is cytoplasmic in worms. We discuss how the phenotype of clk-2 mutants could be the result of altered patterns of gene expression.
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Affiliation(s)
- C Bénard
- Department of Biology, McGill University, 1205 Avenue Dr Penfield, H3A 1B1, Montréal, Québec, Canada
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