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A novel COQ7 mutation causing primarily neuromuscular pathology and its treatment options. Mol Genet Metab Rep 2022; 31:100877. [PMID: 35782625 PMCID: PMC9248208 DOI: 10.1016/j.ymgmr.2022.100877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 04/27/2022] [Indexed: 11/21/2022] Open
Abstract
Coenzyme Q10 (CoQ10) is necessary as electron transporter in mitochondrial respiration and other cellular functions. CoQ10 is synthesized by all cells and defects in the synthesis pathway result in primary CoQ10 deficiency that frequently leads to severe mitochondrial disease syndrome. CoQ10 is exceedingly hydrophobic, insoluble, and poorly bioavailable, with the result that dietary CoQ10 supplementation produces no or only minimal relief for patients. We studied a patient from Turkey and identified and characterized a new mutation in the CoQ10 biosynthetic gene COQ7 (c.161G > A; p.Arg54Gln). We find that unexpected neuromuscular pathology can accompany CoQ10 deficiency caused by a COQ7 mutation. We also show that by-passing the need for COQ7 by providing the unnatural precursor 2,4-dihydroxybenzoic acid, as has been proposed, is unlikely to be an effective and safe therapeutic option. In contrast, we show for the first time in human patient cells that the respiratory defect resulting from CoQ10 deficiency is rescued by providing CoQ10 formulated with caspofungin (CF/CoQ). Caspofungin is a clinically approved intravenous fungicide whose surfactant properties lead to CoQ10 micellization, complete water solubilization, and efficient uptake by cells and organs in animal studies. These findings reinforce the possibility of using CF/CoQ in the clinical treatment of CoQ10-deficient patients.
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Deng Y, Liu H, Huang Q, Tu L, Hu L, Zheng B, Sun H, Lu D, Guo C, Zhou L. Mechanism of Longevity Extension of Caenorhabditis elegans Induced by Schizophyllum commune Fermented Supernatant With Added Radix Puerariae. Front Nutr 2022; 9:847064. [PMID: 35360681 PMCID: PMC8963188 DOI: 10.3389/fnut.2022.847064] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2022] [Accepted: 02/07/2022] [Indexed: 12/11/2022] Open
Abstract
Schizophyllum commune (S. commune) fermented supernatant with added Radix Puerariae (SC-RP) showed significant antioxidant activity in our previous work. However, the possible lifespan and healthspan extending the capacity of Caenorhabditis elegans (C. elegans) and the underlying mechanism were not illuminated. In this study, the effect of SC-RP on extending the lifespan and improving stress resistance of C. elegans were examined. Additionally, the underlying lifespan extending molecular mechanisms of SC-RP were explored. Treated with SC-RP at 10 μg/mL, the lifespan of C. elegans increased by 24.89% (P < 0.01). Also, SC-RP prolonged the healthspan of the nematode, including reducing lipofuscin levels, improving mobility and enhancing resistance to oxidative stress and heat shock. Moreover, superoxide dismutase and catalase activities were increased for SC-RP treated C. elegans. Meantime the intracellular levels of thiobarbituric acid reactive substances (TBARS) and reactive oxygen species (ROS) were attenuated. Express levels of eight genes including daf-2, daf-16, sod-3, skn-1, gst-4, clk-1, age-1 and mev-1 were analyzed by RT-PCR method for possible C. elegan anti-aging mechanisms of SC-RP. Expression levels of key genes daf-2, gst-4 and sod-3 were up-regulated, while that of daf-16, skn-1, and clk-1 were down-regulated. The results suggest that SC-RP could extend the lifespan and healthspan of C. elegans significantly, and the IIS pathway, SKN-1/Nrf2 pathway and mitochondrial metabolism pathway were primarily considered associated. Thus, SC-RP is a potential component to improve aging and aging-related symptoms as new functional materials.
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Affiliation(s)
- Yongfei Deng
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
- Research and Development Center, Guangdong Marubi Biotechnology Co., Ltd., Guangzhou, China
- School of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Han Liu
- Research and Development Center, Guangdong Marubi Biotechnology Co., Ltd., Guangzhou, China
| | - Qian Huang
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
| | - Lingyun Tu
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
- Research and Development Center, Guangdong Marubi Biotechnology Co., Ltd., Guangzhou, China
- School of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Lu Hu
- Research and Development Center, Guangdong Marubi Biotechnology Co., Ltd., Guangzhou, China
| | - Bisheng Zheng
- School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Huaiqing Sun
- Research and Development Center, Guangdong Marubi Biotechnology Co., Ltd., Guangzhou, China
| | - Dengjun Lu
- School of Light Industry and Food Engineering, Guangxi University, Nanning, China
| | - Chaowan Guo
- Research and Development Center, Guangdong Marubi Biotechnology Co., Ltd., Guangzhou, China
| | - Lin Zhou
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates, School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, China
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3
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Song B, Zheng B, Li T, Liu RH. SKN-1 is involved in combination of apple peels and blueberry extracts synergistically protecting against oxidative stress in Caenorhabditis elegans. Food Funct 2021; 11:5409-5419. [PMID: 32469357 DOI: 10.1039/d0fo00891e] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Increased consumption of fruits and vegetables is associated with reduced risk of age-related functional declines and chronic diseases, primarily attributed to their bioactive phytochemicals. Apples and blueberries are rich in phytochemicals with a wide range of biological activities and health benefits. Our previous research has shown the combination of apple peel extracts (APE) and blueberry extracts (BE) can synergistically promote the lifespan of Caenorhabditis elegans (C. elegans). The objectives of this study were to determine whether the extension of lifespan was involved in regulation of oxidative stress, and to explore the underlying mechanisms of action. The results showed that the combination of APE and BE could synergistically ameliorate oxidative stress by improving antioxidant enzyme activities and enhancing resistance to paraquat. Meanwhile, treatment with APE plus BE could down-regulate the overexpression of reactive oxygen species (ROS) and affect the expression of antioxidant related genes, including sod-3, cat-1, ctl-1, skn-1, mev-1 and isp-1. However, administration with APE plus BE abolished the extension of the lifespan of skn-1(zu135) mutants, and inhibited the expression of skn-1 downstream genes, including gcs-1, gst-4 and gst-7. In addition, supplementation with APE plus BE could promote the migration of SKN-1 into the nucleus, which eliminated improvement to ROS and paraquat. In conclusion, the combination of APE and BE could synergistically protect against oxidative stress in C. elegans via the SKN-1/Nrf2 pathway. This study provided the theoretical basis to explore the combination of phytochemicals in the prevention of aging regulated by oxidative stress.
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Affiliation(s)
- Bingbing Song
- School of Food Sciences and Engineering, South China University of Technology, Guangzhou 510641, China.
| | - Bisheng Zheng
- School of Food Sciences and Engineering, South China University of Technology, Guangzhou 510641, China. and Guangdong ERA Food & Life Health Research Institute, Guangzhou, 510530, China and Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA.
| | - Tong Li
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA.
| | - Rui Hai Liu
- Department of Food Science, Stocking Hall, Cornell University, Ithaca, NY 14853, USA.
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4
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López-Lluch G. Coenzyme Q homeostasis in aging: Response to non-genetic interventions. Free Radic Biol Med 2021; 164:285-302. [PMID: 33454314 DOI: 10.1016/j.freeradbiomed.2021.01.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/30/2020] [Accepted: 01/11/2021] [Indexed: 12/28/2022]
Abstract
Coenzyme Q (CoQ) is a key component for many essential metabolic and antioxidant activities in cells in mitochondria and cell membranes. Mitochondrial dysfunction is one of the hallmarks of aging and age-related diseases. Deprivation of CoQ during aging can be the cause or the consequence of this mitochondrial dysfunction. In any case, it seems clear that aging-associated CoQ deprivation accelerates mitochondrial dysfunction in these diseases. Non-genetic prolongevity interventions, including CoQ dietary supplementation, can increase CoQ levels in mitochondria and cell membranes improving mitochondrial activity and delaying cell and tissue deterioration by oxidative damage. In this review, we discuss the importance of CoQ deprivation in aging and age-related diseases and the effect of prolongevity interventions on CoQ levels and synthesis and CoQ-dependent antioxidant activities.
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Affiliation(s)
- Guillermo López-Lluch
- Universidad Pablo de Olavide, Centro Andaluz de Biología Del Desarrollo, CABD-CSIC, CIBERER, Instituto de Salud Carlos III, Carretera de Utrera Km. 1, 41013, Sevilla, Spain.
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5
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Kirby CS, Patel MR. Elevated mitochondrial DNA copy number found in ubiquinone-deficient clk-1 mutants is not rescued by ubiquinone precursor 2-4-dihydroxybenzoate. Mitochondrion 2021; 58:38-48. [PMID: 33581333 DOI: 10.1016/j.mito.2021.02.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 01/13/2021] [Accepted: 02/01/2021] [Indexed: 01/28/2023]
Abstract
Inside mitochondria reside semi-autonomous genomes, called mtDNA. mtDNA is multi-copy per cell and mtDNA copy number can vary from hundreds to thousands of copies per cell. The variability of mtDNA copy number between tissues, combined with the lack of variability of copy number within a tissue, suggest a homeostatic copy number regulation mechanism. Mutations in the gene encoding the Caenorhabditis elegans hydroxylase, CLK-1, result in elevated mtDNA. CLK-1's canonical role in ubiquinone biosynthesis results in clk-1 mutants lacking ubiquinone. Importantly, clk-1 mutants also exhibit slowed biological timing phenotypes (pharyngeal pumping, defecation, development) and an activated stress response (UPRmt). These biological timing and stress phenotypes have been attributed to ubiquinone deficiency; however, it is unknown whether the mtDNA phenotype is also due to ubiquinone deficiency. To test this, in animals carrying the uncharacterized clk-1 (ok1247) mutant allele, we supplemented with an exogenous ubiquinone precursor 2-4-dihydroxybenzoate (DHB), which has previously been shown to restore ubiquinone biosynthesis. We measured phenotypes as a function of DHB across a log-scale range. Unlike the biological timing and stress phenotypes, the elevated mtDNA phenotype was not rescued. Since CLK-1's canonical role is in ubiquinone biosynthesis and DHB does not rescue mtDNA copy number, we infer CLK-1 has an additional function in homeostatic mtDNA copy number regulation.
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Affiliation(s)
- Cait S Kirby
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Maulik R Patel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA; Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Diabetes Research and Training Center, Vanderbilt University, Nashville, TN 37232, USA.
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6
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Wang Y, Hekimi S. Micellization of coenzyme Q by the fungicide caspofungin allows for safe intravenous administration to reach extreme supraphysiological concentrations. Redox Biol 2020; 36:101680. [PMID: 32810741 PMCID: PMC7451649 DOI: 10.1016/j.redox.2020.101680] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/03/2020] [Accepted: 08/04/2020] [Indexed: 12/15/2022] Open
Abstract
Coenzyme Q10 (CoQ10; also known as ubiquinone) is a vital, redox-active membrane component that functions as obligate electron transporter in the mitochondrial respiratory chain, as cofactor in other enzymatic processes and as antioxidant. CoQ10 supplementation has been widely investigated for treating a variety of acute and chronic conditions in which mitochondrial function or oxidative stress play a role. In addition, it is used as replacement therapy in patients with CoQ deficiency including inborn primary CoQ10 deficiency due to mutations in CoQ10-biosynthetic genes as well as secondary CoQ10 deficiency, which is frequently observed in patients with mitochondrial disease syndrome and in other conditions. However, despite many tests and some promising results, whether CoQ10 treatment is beneficial in any indication has remained inconclusive. Because CoQ10 is highly insoluble, it is only available in oral formulations, despite its very poor oral bioavailability. Using a novel model of CoQ-deficient cells, we screened a library of FDA-approved drugs for an activity that could increase the uptake of exogenous CoQ10 by the cell. We identified the fungicide caspofungin as capable of increasing the aqueous solubility of CoQ10 by several orders of magnitude. Caspofungin is a mild surfactant that solubilizes CoQ10 by forming nano-micelles with unique properties favoring stability and cellular uptake. Intravenous administration of the formulation in mice achieves unprecedented increases in CoQ10 plasma levels and in tissue uptake, with no observable toxicity. As it contains only two safe components (caspofungin and CoQ10), this injectable formulation presents a high potential for clinical safety and efficacy. Coenzyme Q10 (CoQ10) can be solubilized by the antifungal drug caspofungin (CF). CF is a mild surfactant and solubilizes CoQ10 in water by forming micellar structures with a high CoQ10 content. CF/CoQ10 micelles have unique properties favoring rapid and efficient uptake into cells and mitochondria. CF/CoQ10 micelles can be intravenously administrated without signs of toxicity. Intravenous administration of CF/CoQ10 in mice achieves unprecedented elevation of CoQ10 plasma levels and tissue uptake.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada.
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Abstract
Invertebrates are becoming more popular and, as collections age, clients may seek veterinary intervention where the welfare of the animal must be considered. This article covers aging in many invertebrate species but with a focus on species likely to be seen in general practice. Supportive care may be an option to prolong life, but euthanasia must be considered for invertebrates with age-related unmanageable conditions.
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Affiliation(s)
- Sarah Pellett
- Animates Veterinary Clinic, 2 The Green, Thurlby, Lincolnshire PE10 0EB, UK.
| | - Michelle O'Brien
- Wildfowl & Wetlands Trust, Newgrounds Lane, Slimbridge, Gloucestershire GL2 7BT, UK
| | - Benjamin Kennedy
- Anton Vets, Anton Trading Estate, Anton Mill Road, Andover SP10 2NJ, UK
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8
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Anti-aging Effects of Calorie Restriction (CR) and CR Mimetics based on the Senoinflammation Concept. Nutrients 2020; 12:nu12020422. [PMID: 32041168 PMCID: PMC7071238 DOI: 10.3390/nu12020422] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/29/2020] [Accepted: 02/03/2020] [Indexed: 12/12/2022] Open
Abstract
Chronic inflammation, a pervasive feature of the aging process, is defined by a continuous, multifarious, low-grade inflammatory response. It is a sustained and systemic phenomenon that aggravates aging and can lead to age-related chronic diseases. In recent years, our understanding of age-related chronic inflammation has advanced through a large number of investigations on aging and calorie restriction (CR). A broader view of age-related inflammation is the concept of senoinflammation, which has an outlook beyond the traditional view, as proposed in our previous work. In this review, we discuss the effects of CR on multiple phases of proinflammatory networks and inflammatory signaling pathways to elucidate the basic mechanism underlying aging. Based on studies on senoinflammation and CR, we recognized that senescence-associated secretory phenotype (SASP), which mainly comprises cytokines and chemokines, was significantly increased during aging, whereas it was suppressed during CR. Further, we recognized that cellular metabolic pathways were also dysregulated in aging; however, CR mimetics reversed these effects. These results further support and enhance our understanding of the novel concept of senoinflammation, which is related to the metabolic changes that occur in the aging process. Furthermore, a thorough elucidation of the effect of CR on senoinflammation will reveal key insights and allow possible interventions in aging mechanisms, thus contributing to the development of new therapies focused on improving health and longevity.
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Wang X, Li H, Liu Y, Wu H, Wang H, Jin S, Lu Y, Chang S, Liu R, Peng Y, Guo Z, Wang X. Velvet antler methanol extracts (MEs) protects against oxidative stress in Caenorhabditis elegans by SKN-1. Biomed Pharmacother 2019; 121:109668. [PMID: 31766103 DOI: 10.1016/j.biopha.2019.109668] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 09/30/2019] [Accepted: 10/14/2019] [Indexed: 02/07/2023] Open
Abstract
Velvet antler is one of the most important animal medicines or functional foods widely used in East Asia for many centuries, which has several biological activities including anti-ageing and health promotion. To date, the mechanism underlying these effects of velvet antler is widely studied by its protein or polypeptide components. Few studies have been reported for the function of the other components in velvet antler. Herein, C. elegans is used as the model animal to dissect how none protein components of velvet antler affect in vivo oxidative stress. Methanol extracts (MEs) from velvet antler which has few protein components extends the maximum lifespan of C. elegans compared to the control under oxidative stress, while water extracts (WEs) which is protein-rich component has no apparent function. The activity of MEs is mediated by clk-1 signaling pathway, but not via daf-2, eat-2 or glp-1 pathway. Further investigations show MEs decrease endogenous ROS by promoting SKN-1 nuclei translocation, subsequently up-regulating the expression of its target genes gst-4, gst-7 and gst-10 in C. elegans. In all, MEs, the none protein components of velvet antler, protects against oxidative stress in C. elegans, which indicates it might be a product with potential of being a curative medicine.
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Affiliation(s)
- Xue Wang
- Department of Food Science and Engineering, Jilin Agricultural University, Changchun, 130118, China; State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China
| | - Hongyuan Li
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Ying Liu
- Key Laboratory of Special Animal Molecular Biology of Jilin Province, Specialty Research Institute of Chinese Academy of Agricultural Sciences, Changchun, Jilin 130112, China
| | - Hua Wu
- Department of Food Science and Engineering, Jilin Agricultural University, Changchun, 130118, China
| | - Hongshuang Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China
| | - Sha Jin
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Yuyuan Lu
- State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China
| | - Shuzhuo Chang
- Key Laboratory of Special Animal Molecular Biology of Jilin Province, Specialty Research Institute of Chinese Academy of Agricultural Sciences, Changchun, Jilin 130112, China
| | - Renjie Liu
- Department of Food Science and Engineering, Jilin Agricultural University, Changchun, 130118, China
| | - Yinghua Peng
- Key Laboratory of Special Animal Molecular Biology of Jilin Province, Specialty Research Institute of Chinese Academy of Agricultural Sciences, Changchun, Jilin 130112, China.
| | - Zhijun Guo
- College of Marine Science and Biological Engineering, Qingdao University of Science & Technology, Qingdao, 266042, China; College of Agriculture, Yanbian University, Yanji, 133002, China.
| | - Xiaohui Wang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, 210009, China; Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, China; Department of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, 230026, China.
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10
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Molenaars M, Janssens GE, Santermans T, Lezzerini M, Jelier R, MacInnes AW, Houtkooper RH. Mitochondrial ubiquinone-mediated longevity is marked by reduced cytoplasmic mRNA translation. Life Sci Alliance 2018; 1. [PMID: 30198021 PMCID: PMC6126614 DOI: 10.26508/lsa.201800082] [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] [Indexed: 01/26/2023] Open
Abstract
This study uses polysomal RNA sequencing to show that the translational efficiency of specific mRNA changes in long-lived Caenorhabditis elegans with reduced ubiquinone synthesis. Mutations in the clk-1 gene impair mitochondrial ubiquinone biosynthesis and extend the lifespan in Caenorhabditis elegans. We demonstrate here that this life extension is linked to the repression of cytoplasmic mRNA translation, independent of the alleged nuclear form of CLK-1. Clk-1 mutations inhibit polyribosome formation similarly to daf-2 mutations that dampen insulin signaling. Comparisons of total versus polysomal RNAs in clk-1(qm30) mutants reveal a reduction in the translational efficiencies of mRNAs coding for elements of the translation machinery and an increase in those coding for the oxidative phosphorylation and autophagy pathways. Knocking down the transcription initiation factor TATA-binding protein-associated factor 4, a protein that becomes sequestered in the cytoplasm during early embryogenesis to induce transcriptional silencing, ameliorates the clk-1 inhibition of polyribosome formation. These results underscore a prominent role for the repression of cytoplasmic protein synthesis in eukaryotic lifespan extension and suggest that mutations impairing mitochondrial function are able to exploit this repression similarly to reductions of insulin signaling. Moreover, this report reveals an unexpected role for TATA-binding protein-associated factor 4 as a repressor of polyribosome formation when ubiquinone biosynthesis is compromised.
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Affiliation(s)
- Marte Molenaars
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, Meibergdreef 9, Amsterdam, The Netherlands
| | - Georges E Janssens
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, Meibergdreef 9, Amsterdam, The Netherlands
| | - Toon Santermans
- CMPG - Predictive Genetics and Multicellular Systems, University of Leuven, B-3001 Leuven, Belgium
| | - Marco Lezzerini
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, Meibergdreef 9, Amsterdam, The Netherlands
| | - Rob Jelier
- CMPG - Predictive Genetics and Multicellular Systems, University of Leuven, B-3001 Leuven, Belgium
| | - Alyson W MacInnes
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, Meibergdreef 9, Amsterdam, The Netherlands
| | - Riekelt H Houtkooper
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam Gastroenterology & Metabolism, Meibergdreef 9, Amsterdam, The Netherlands
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11
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Mitohormesis, an Antiaging Paradigm. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 340:35-77. [DOI: 10.1016/bs.ircmb.2018.05.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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12
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Zhang L, Yang H, Zhang W, Liang Z, Huang Q, Xu G, Zhen X, Zheng LT. Clk1-regulated aerobic glycolysis is involved in glioma chemoresistance. J Neurochem 2017; 142:574-588. [PMID: 28581641 DOI: 10.1111/jnc.14096] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 06/01/2017] [Accepted: 06/01/2017] [Indexed: 02/01/2023]
Abstract
Chemoresistance remains a major challenge for the treatment of glioma. In this study, we investigated the role of Clock 1 (Clk1), which encodes an enzyme that is necessary for ubiquinone biosynthesis in glioma chemoresistance in vitro. The results showed that Clk1 was highly expressed in GL261 mouse glioma cells which were most sensitive to 1,3Bis (2-chloroethyl) 1 nitrosourea (BCNU) while was low expressed in BCNU resistant cells such as glioma cancer stem cells, T98G, U87MG and U251 glioma cells. Knockdown of Clk1 in GL261 glioma cells significantly reduced BCNU- or cisplatin-induced cell apoptosis, whereas the proliferative activity and the expression of multidrug resistance-related genes including MDR1, O6-methylguanine-DNA methyltransferase, and GSTP1 were not changed. When Clk1 was re-expressed in Clk1 knockdown GL261 glioma cells, the BCNU sensitivity was restored. The mechanistic study revealed that knockdown of Clk1 in GL261 glioma cells increased aerobic glycolysis including high glucose consumption, lactate production, and up-regulation of glycolysis-associated genes. Inhibition of glycolysis can reverse the chemoresistance elicited by Clk1 knockdown in GL261 cells. Moreover, knockdown of Clk1 induced HIF-1α expression in GL261 glioma cells which was found to be mediated by AMP-activated protein kinase (AMPK)/mechanistic target of rapamycin (mTOR) signaling pathway. Both metformin and rapamycin reversed the chemoresistance of Clk1 knockdown GL261 glioma cells. Over-expression of Clk1 significantly increased the sensitivity of T98G or U251 human glioblastoma cells to BCNU which was accompanied by decreased lactate secretion, decreased expression of HIF-1α, AMPK activation, and inhibition of mTOR pathway. Inhibition of glycolysis or activation of AMPK did not alter Clk1 expression in variant glioma cell lines suggesting that aerobic glycolysis is not an upstream event of Clk1 expression in glioma cells. Taken together, our results revealed, for the first time, that mitochondrial Clk1 regulated chemoresistance in glioma cells through AMPK/mTOR/HIF-1α mediated glycolysis pathway.
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Affiliation(s)
- Li Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.,College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou, China
| | - Huicui Yang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.,College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou, China
| | - Wenbin Zhang
- Department of neurosurgery, Brain Hospital affiliated to Nanjing medical University, Nanjing, China
| | - Zhongqin Liang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.,College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou, China
| | - Qiang Huang
- Department of Neurosurgery, the Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Guoqiang Xu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.,College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou, China
| | - Xuechu Zhen
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.,College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou, China
| | - Long Tai Zheng
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.,College of Pharmaceutical Sciences and the Collaborative Innovation Center for Brain Science, Soochow University, Suzhou, China
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13
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A single biochemical activity underlies the pleiotropy of the aging-related protein CLK-1. Sci Rep 2017; 7:859. [PMID: 28404998 PMCID: PMC5429816 DOI: 10.1038/s41598-017-00754-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/09/2017] [Indexed: 11/23/2022] Open
Abstract
The Caenorhabditis elegans clk-1 gene and the orthologous mouse gene Mclk1 encode a mitochondrial hydroxylase that is necessary for the biosynthesis of ubiquinone (UQ). Mutations in these genes produce broadly pleiotropic phenotypes in both species, including a lengthening of animal lifespan. A number of features of the C. elegans clk-1 mutants, including a maternal effect, particularly extensive pleiotropy, as well as unexplained differences between alleles have suggested that CLK-1/MCLK1 might have additional functions besides that in UQ biosynthesis. In addition, a recent study suggested that a cryptic nuclear localization signal could lead to nuclear localization in cultured mammalian cell lines. Here, by using immunohistochemical techniques in worms and purification techniques in mammalian cells, we failed to detect any nuclear enrichment of the MCLK1 or CLK-1 proteins and any biological activity of a C. elegans CLK-1 protein devoid of a mitochondrial localization sequence. In addition, and most importantly, by pharmacologically restoring UQ biosynthesis in clk-1 null mutants we show that loss of UQ biosynthesis is responsible for all phenotypes resulting from loss of CLK-1, including behavioral phenotypes, altered expression of mitochondrial quality control genes, and lifespan.
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Abstract
One of the original hypotheses of organismal longevity posits that aging is the natural result of entropy on the cells, tissues, and organs of the animal—a slow, inexorable slide into nonfunctionality caused by stochastic degradation of its parts. We now have evidence that aging is instead at least in part genetically regulated. Many mutations have been discovered to extend lifespan in organisms of all complexities, from yeast to mammals. The study of metazoan model organisms, such as Caenorhabditis elegans, has been instrumental in understanding the role of genetics in the cell biology of aging. Longevity mutants across the spectrum of model organisms demonstrate that rates of aging are regulated through genetic control of cellular processes. The regulation and subsequent breakdown of cellular processes represent a programmatic decision by the cell to either continue or abandon maintenance procedures with age. Our understanding of cell biological processes involved in regulating aging have been particularly informed by longevity mutants and treatments, such as reduced insulin/IGF-1 signaling and dietary restriction, which are critical in determining the distinction between causes of and responses to aging and have revealed a set of downstream targets that participate in a range of cell biological activities. Here we briefly review some of these important cellular processes.
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Affiliation(s)
- Race DiLoreto
- Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
| | - Coleen T Murphy
- Department of Molecular Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544
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15
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Mitochondrial and cytoplasmic ROS have opposing effects on lifespan. PLoS Genet 2015; 11:e1004972. [PMID: 25671321 PMCID: PMC4335496 DOI: 10.1371/journal.pgen.1004972] [Citation(s) in RCA: 148] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 12/22/2014] [Indexed: 01/21/2023] Open
Abstract
Reactive oxygen species (ROS) are highly reactive, oxygen-containing molecules that can cause molecular damage within the cell. While the accumulation of ROS-mediated damage is widely believed to be one of the main causes of aging, ROS also act in signaling pathways. Recent work has demonstrated that increasing levels of superoxide, one form of ROS, through treatment with paraquat, results in increased lifespan. Interestingly, treatment with paraquat robustly increases the already long lifespan of the clk-1 mitochondrial mutant, but not other long-lived mitochondrial mutants such as isp-1 or nuo-6. To genetically dissect the subcellular compartment in which elevated ROS act to increase lifespan, we deleted individual superoxide dismutase (sod) genes in clk-1 mutants, which are sensitized to ROS. We find that only deletion of the primary mitochondrial sod gene, sod-2 results in increased lifespan in clk-1 worms. In contrast, deletion of either of the two cytoplasmic sod genes, sod-1 or sod-5, significantly decreases the lifespan of clk-1 worms. Further, we show that increasing mitochondrial superoxide levels through deletion of sod-2 or treatment with paraquat can still increase lifespan in clk-1;sod-1 double mutants, which live shorter than clk-1 worms. The fact that mitochondrial superoxide can increase lifespan in worms with a detrimental level of cytoplasmic superoxide demonstrates that ROS have a compartment specific effect on lifespan - elevated ROS in the mitochondria acts to increase lifespan, while elevated ROS in the cytoplasm decreases lifespan. This work also suggests that both ROS-dependent and ROS-independent mechanisms contribute to the longevity of clk-1 worms.
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16
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Lapointe J, Hughes B, Bigras E, Hekimi S. Compensatory elevation of voluntary activity in mouse mutants with impaired mitochondrial energy metabolism. Physiol Rep 2014; 2:2/11/e12214. [PMID: 25413331 PMCID: PMC4255820 DOI: 10.14814/phy2.12214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mitochondria play a crucial role in determining whole‐body metabolism and exercise
capacity. Genetic mouse models of mild mitochondrial dysfunction provide an opportunity to
understand how mitochondrial function affects these parameters. MCLK1 (a.k.a. Coq7) is an enzyme
implicated in the biosynthesis of ubiquinone (UQ; Coenzyme Q). Low levels of MCLK1 in
Mclk1+/− heterozygous mutants lead to abnormal
sub‐mitochondrial distribution of UQ, impaired mitochondrial function, elevated mitochondrial
oxidative stress, and increased lifespan. Here, we report that young
Mclk1+/− males, but not females, show a significant
decrease in whole‐body metabolic rate as measured by indirect calorimetry. Such a
sex‐specific effect of mitochondrial dysfunction on energy metabolism has also been reported
for heterozygous mice carrying a mutation for the gene encoding the “Rieske” protein
of mitochondrial complex III
(RISP+/P224S). We find that both
Mclk1+/− and
RISP+/P224S males are capable of
restoring their defective metabolic rates by making significantly more voluntary use of a running
wheel compared to wild type. However, this increase in voluntary activity does not reflect their
exercise capacity, which we found to be impaired as revealed by a shorter treadmill distance run
before exhaustion. In contrast to what is observed in
Mclk1+/− and
RISP+/P224S mutants,
Sod2+/− mice with elevated oxidative stress and
major mitochondrial dysfunction did not increase voluntary activity. Our study reveals a
sex‐specific effect on how impaired mitochondrial function impacts whole‐body energy
metabolism and locomotory behavior, and contributes to the understanding of the metabolic and
behavioral consequences of mitochondrial disorders. Mitochondria play a crucial role in determining whole‐body metabolism, lifespan and
exercise capacity. This study reports sex‐specific effects of mitochondrial dysfunction,
resulting in increased spontaneous activity in response to impaired metabolic rates. These findings
contribute to the understanding of the metabolic and behavioral consequences of mitochondrial
disorders.
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Affiliation(s)
- Jérôme Lapointe
- Department of Biology, McGill University, Montréal, Quebec, Canada Agriculture and Agri-Food Canada, 2000 College St., Sherbrooke, J1M 0C8, Quebec, Canada
| | - Bryan Hughes
- Department of Biology, McGill University, Montréal, Quebec, Canada Department of Pharmacology, University of Alberta, Edmonton, T6G 2S2, Alberta, Canada
| | - Eve Bigras
- Department of Biology, McGill University, Montréal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montréal, Quebec, Canada
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17
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Kim DH, Park MH, Chung KW, Kim MJ, Jung YR, Bae HR, Jang EJ, Lee JS, Im DS, Yu BP, Chung HY. The essential role of FoxO6 phosphorylation in aging and calorie restriction. AGE (DORDRECHT, NETHERLANDS) 2014; 36:9679. [PMID: 25007762 PMCID: PMC4150907 DOI: 10.1007/s11357-014-9679-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 06/18/2014] [Indexed: 06/03/2023]
Abstract
Changes in the activities of FoxOs caused by phosphorylation, acetylation, or ubiquitination induce expressional changes in the genes involved in the modulation of oxidative stress by modifying histones and chromatins and can substantially alter cellular functions during aging and age-related diseases. However, the precise role that FoxO6, a novel member of the FoxO class of transcription factors, plays in the aging kidney has not been determined. The purpose of this study was to determine the role played by FoxO6 in the maintenance of redox homeostasis in HEK293T cells and aged kidney tissues isolated from ad libitum (AL)-fed and 40 % calorie restriction (CR) rats. The results obtained from AL-fed rats showed that diminished FoxO6 activity during aging was caused by FoxO6 phosphorylation, which disabled its transcriptional activity. In contrast, CR rats were found to have significantly higher FoxO6 activities and maintained redox balance. To determine the molecular mechanism responsible for FoxO6 modification by age-related oxidative stress, we examined H2O2-treated HEK293T cells in which FoxO6 was inactivated by phosphorylation and found that H2O2-induced oxidative stress promoted FoxO6 phosphorylation via PI3K/Akt signaling. The results of this study show that the protective role of FoxO6 in the aging process may in part be related to its ability to attenuate oxidative stress by upregulating catalase expression, as shown in CR. This delineation of the role of FoxO6 expands understanding of the pathological and physiological mechanisms of aging.
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Affiliation(s)
- Dae Hyun Kim
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Min Hi Park
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Ki Wung Chung
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Min Jo Kim
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Yu Ri Jung
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Ha Ram Bae
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Eun Ji Jang
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Jun Sik Lee
- />Department of Biology, College of Natural Science, Chosun University, Gwangju, 501-759 Republic of Korea
| | - Dong Soon Im
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
| | - Byung Pal Yu
- />Department of Physiology, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA
| | - Hae Young Chung
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, Gumjung-gu, Busan, 609-735 Republic of Korea
- />Molecular Inflammation Research Center for Aging Intervention (MRCA), College of Pharmacy, Pusan National University, San 30, Jangjun-dong, Gumjung-gu, Busan, 609-735 Republic of Korea
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18
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Abstract
Ubiquinone (UQ), also known as coenzyme Q (CoQ), is a redox-active lipid present in all cellular membranes where it functions in a variety of cellular processes. The best known functions of UQ are to act as a mobile electron carrier in the mitochondrial respiratory chain and to serve as a lipid soluble antioxidant in cellular membranes. All eukaryotic cells synthesize their own UQ. Most of the current knowledge on the UQ biosynthetic pathway was obtained by studying Escherichia coli and Saccharomyces cerevisiae UQ-deficient mutants. The orthologues of all the genes known from yeast studies to be involved in UQ biosynthesis have subsequently been found in higher organisms. Animal mutants with different genetic defects in UQ biosynthesis display very different phenotypes, despite the fact that in all these mutants the same biosynthetic pathway is affected. This review summarizes the present knowledge of the eukaryotic biosynthesis of UQ, with focus on the biosynthetic genes identified in animals, including Caenorhabditis elegans, rodents, and humans. Moreover, we review the phenotypes of mutants in these genes and discuss the functional consequences of UQ deficiency in general.
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Affiliation(s)
- Ying Wang
- Department of Biology, McGill University, Montréal, Quebec, Canada
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19
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Lifespan extension and paraquat resistance in a ubiquinone-deficient Escherichia coli mutant depend on transcription factors ArcA and TdcA. Aging (Albany NY) 2011; 3:291-303. [PMID: 21464517 PMCID: PMC3091522 DOI: 10.18632/aging.100301] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We recently reported a genome-wide screen for extended stationary phase survival in Escherichia coli. One of the mutants recovered is deleted for ubiG, which encodes a methyltransferase required for the biosynthesis of ubiquinone. The ubiG mutant exhibits longer lifespan, as well as enhanced resistance to thermal and oxidative stress compared to wt at extracellular pH9. The longevity of the mutant, as well as its resistance to the superoxide-generating agent paraquat, is partially dependent on the hypoxia-inducible transcription factor ArcA. A microarray analysis revealed several genes whose expression is either suppressed or enhanced by ArcA in the ubiG mutant. TdcA is a transcription factor involved in the transport and metabolism of amino acids during anaerobic growth. Its enhanced expression in the ubiG mutant is dependent on ArcA. Our data are consistent with the hypothesis that ArcA and TdcA function in the same genetic pathway to increase lifespan and enhance oxidative stress resistance in the ubiG mutant. Our results might be relevant for the elucidation of the mechanism of lifespan extension in mutant mice and worms bearing mutations in ubiquinone biosynthetic genes.
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20
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Branicky R, Desjardins D, Liu JL, Hekimi S. Lipid transport and signaling in Caenorhabditis elegans. Dev Dyn 2010; 239:1365-77. [PMID: 20151418 DOI: 10.1002/dvdy.22234] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The strengths of the Caenorhabditis elegans model have been recently applied to the study of the pathways of lipid storage, transport, and signaling. As the lipid storage field has recently been reviewed, in this minireview we (1) discuss some recent studies revealing important physiological roles for lipases in mobilizing lipid reserves, (2) describe various pathways of lipid transport, with a particular focus on the roles of lipoproteins, (3) debate the utility of using C. elegans as a model for human dyslipidemias that impinge on atherosclerosis, and (4) describe several systems where lipids affect signaling, highlighting the particular properties of lipids as information-carrying molecules. We conclude that the study of lipid biology in C. elegans exemplifies the advantages afforded by a whole-animal model system where interactions between tissues and organs, and functions such as nutrient absorption, distribution, and storage, as well as reproduction can all be studied simultaneously.
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Affiliation(s)
- Robyn Branicky
- Department of Biology, McGill University, Montreal, Quebec, Canada
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21
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Kato K, Cui S, Kuick R, Mineishi S, Hexner E, Ferrara JLM, Emerson SG, Zhang Y. Identification of stem cell transcriptional programs normally expressed in embryonic and neural stem cells in alloreactive CD8+ T cells mediating graft-versus-host disease. Biol Blood Marrow Transplant 2010; 16:751-71. [PMID: 20116439 DOI: 10.1016/j.bbmt.2010.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Accepted: 01/20/2010] [Indexed: 02/01/2023]
Abstract
A hallmark of graft-versus-host-disease (GVHD), a life-threatening complication after allogeneic hematopoietic stem cell transplantation, is the cytopathic injury of host tissues mediated by persistent alloreactive effector T cells (T(E)). However, the mechanisms that regulate the persistence of alloreactive T(E) during GVHD remain largely unknown. Using mouse GVHD models, we demonstrate that alloreactive CD8(+) T(E) rapidly diminished in vivo when adoptively transferred into irradiated secondary congenic recipient mice. In contrast, although alloreactive CD8(+) T(E) underwent massive apoptosis upon chronic exposure to alloantigens, they proliferated in vivo in secondary allogeneic recipients, persisted, and caused severe GVHD. Thus, the continuous proliferation of alloreactive CD8(+) T(E), which is mediated by alloantigenic stimuli rather than homeostatic factors, is critical to maintaining their persistence. Gene expression profile analysis revealed that although alloreactive CD8(+) T(E) increased the expression of genes associated with cell death, they activated a group of stem cell genes normally expressed in embryonic and neural stem cells. Most of these stem cell genes are associated with cell cycle regulation, DNA replication, chromatin modification, and transcription. One of these genes, Ezh2, which encodes a chromatin modifying enzyme, was abundantly expressed in CD8(+) T(E). Silencing Ezh2 significantly reduced the proliferation of alloantigen-activated CD8(+) T cells. Thus, these findings identify that a group of stem cell genes could play important roles in sustaining terminally differentiated alloreactive CD8(+) T(E) and may be therapeutic targets for controlling GVHD.
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Affiliation(s)
- Koji Kato
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan 48109-5942, USA
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22
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23
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Lee SJ, Murphy CT, Kenyon C. Glucose shortens the life span of C. elegans by downregulating DAF-16/FOXO activity and aquaporin gene expression. Cell Metab 2009; 10:379-91. [PMID: 19883616 PMCID: PMC2887095 DOI: 10.1016/j.cmet.2009.10.003] [Citation(s) in RCA: 252] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 08/10/2009] [Accepted: 10/14/2009] [Indexed: 11/16/2022]
Abstract
Many studies have addressed the effect of dietary glycemic index on obesity and diabetes, but little is known about its effect on life span itself. We found that adding a small amount of glucose to the medium (2%) shortened the life span of C. elegans by inhibiting the activities of life span-extending transcription factors that are also inhibited by insulin signaling: the FOXO family member DAF-16 and the heat shock factor HSF-1. This effect involved the downregulation of an aquaporin glycerol channel, aqp-1. We show that changes in glycerol metabolism are likely to underlie the life span-shortening effect of glucose and that aqp-1 may act cell nonautonomously as a feedback regulator in the insulin/IGF-1-signaling pathway. Insulin downregulates similar glycerol channels in mammals, suggesting that this glucose-responsive pathway might be conserved evolutionarily. Together, these findings raise the possibility that a low-sugar diet might have beneficial effects on life span in higher organisms.
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Affiliation(s)
- Seung-Jae Lee
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
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24
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Lapointe J, Stepanyan Z, Bigras E, Hekimi S. Reversal of the mitochondrial phenotype and slow development of oxidative biomarkers of aging in long-lived Mclk1+/- mice. J Biol Chem 2009; 284:20364-74. [PMID: 19478076 DOI: 10.1074/jbc.m109.006569] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although there is a consensus that mitochondrial function is somehow linked to the aging process, the exact role played by mitochondria in this process remains unresolved. The discovery that reduced activity of the mitochondrial enzyme CLK-1/MCLK1 (also known as COQ7) extends lifespan in both Caenorhabditis elegans and mice has provided a genetic model to test mitochondrial theories of aging. We have recently shown that the mitochondria of young, long-lived, Mclk1(+/-) mice are dysfunctional, exhibiting reduced energy metabolism and a substantial increase in oxidative stress. Here we demonstrate that this altered mitochondrial condition in young animals paradoxically results in an almost complete protection from the age-dependent loss of mitochondrial function as well as in a significant attenuation of the rate of development of oxidative biomarkers of aging. Moreover, we show that reduction in MCLK1 levels can also gradually prevent the deterioration of mitochondrial function and associated increase of global oxidative stress that is normally observed in Sod2(+/-) mutants. We hypothesize that the mitochondrial dysfunction observed in young Mclk1(+/-) mutants induces a physiological state that ultimately allows for their slow rate of aging. Thus, our study provides for a unique vertebrate model in which an initial alteration in a specific mitochondrial function is linked to long term beneficial effects on biomarkers of aging and, furthermore, provides for new evidence which indicates that mitochondrial oxidative stress is not causal to aging.
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Affiliation(s)
- Jérôme Lapointe
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
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25
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Yang YY, Gangoiti JA, Sedensky MM, Morgan PG. The effect of different ubiquinones on lifespan in Caenorhabditis elegans. Mech Ageing Dev 2009; 130:370-6. [PMID: 19428456 DOI: 10.1016/j.mad.2009.03.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 02/14/2009] [Accepted: 03/02/2009] [Indexed: 12/20/2022]
Abstract
Ubiquinone (UQ, Coenzyme Q, CoQ) transfers electrons from complexes I and II to complex III in the mitochondrial electron transport chain. Depending on the degree of reduction, UQ can act as either a pro- or an antioxidant. Mutations disrupting ubiquinone synthesis increase lifespan in both the nematode (clk-1) and the mouse (mclk-1). The mutated nematodes survive using exogenous ubiquinone from bacteria, which has a shorter isoprenyl tail length (UQ(8)) than the endogenous nematode ubiquinone (UQ(9)). The mechanism underlying clk-1s increased longevity is not clear. Here we directly measure the effect of different exogenous ubiquinones on clk-1 lifespan and mitochondrial function. We fed clk-1 engineered bacteria that produced UQ(6), UQ(7), UQ(8), UQ(9) or UQ(10), and measured clk-1s lifespan, mitochondrial respiration, ROS production, and accumulated ROS damage to mitochondrial protein. Regardless of dietary UQ, clk-1 animals have increased lifespan, decreased mitochondrial respiration, and decreased ROS damage to mitochondrial protein than N2. However, clk-1 mitochondria did not produce less ROS than N2. The simplest explanation of our results is that clk-1 mitochondria scavenge ROS more effectively than wildtype due to the presence of DMQ(9). Moreover, when compared to other dietary quinones, UQ(10) further decreased mitochondrial oxidative damage and extended adult lifespan in clk-1.
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Affiliation(s)
- Yu-Ying Yang
- Department of Genetics, Case Western Reserve University, Cleveland, OH 44106, USA.
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26
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Miki R, Saiki R, Ozoe Y, Kawamukai M. Comparison of a coq7 deletion mutant with other respiration-defective mutants in fission yeast. FEBS J 2008; 275:5309-24. [DOI: 10.1111/j.1742-4658.2008.06661.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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27
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Chen JH, Hales CN, Ozanne SE. DNA damage, cellular senescence and organismal ageing: causal or correlative? Nucleic Acids Res 2007; 35:7417-28. [PMID: 17913751 PMCID: PMC2190714 DOI: 10.1093/nar/gkm681] [Citation(s) in RCA: 312] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 08/16/2007] [Accepted: 08/17/2007] [Indexed: 01/07/2023] Open
Abstract
Cellular senescence has long been used as a cellular model for understanding mechanisms underlying the ageing process. Compelling evidence obtained in recent years demonstrate that DNA damage is a common mediator for both replicative senescence, which is triggered by telomere shortening, and premature cellular senescence induced by various stressors such as oncogenic stress and oxidative stress. Extensive observations suggest that DNA damage accumulates with age and that this may be due to an increase in production of reactive oxygen species (ROS) and a decline in DNA repair capacity with age. Mutation or disrupted expression of genes that increase DNA damage often result in premature ageing. In contrast, interventions that enhance resistance to oxidative stress and attenuate DNA damage contribute towards longevity. This evidence suggests that genomic instability plays a causative role in the ageing process. However, conflicting findings exist which indicate that ROS production and oxidative damage levels of macromolecules including DNA do not always correlate with lifespan in model animals. Here we review the recent advances in addressing the role of DNA damage in cellular senescence and organismal ageing.
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Affiliation(s)
- Jian-Hua Chen
- Department of Clinical Biochemistry, University of Cambridge, Addenbrooke's Hospital, Cambridge CB2 2QR, UK.
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28
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Houthoofd K, Vanfleteren JR. Public and private mechanisms of life extension in Caenorhabditis elegans. Mol Genet Genomics 2007; 277:601-17. [PMID: 17364197 DOI: 10.1007/s00438-007-0225-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2006] [Accepted: 02/20/2007] [Indexed: 12/18/2022]
Abstract
Model organisms have been widely used to study the ageing phenomenon in order to learn about human ageing. Although the phylogenetic diversity between vertebrates and some of the most commonly used model systems could hardly be greater, several mechanisms of life extension are public (common characteristic in divergent species) and likely share a common ancestry. Dietary restriction, reduced IGF-signaling and, seemingly, reduced ROS-induced damage are the best known mechanisms for extending longevity in a variety of organisms. In this review, we summarize the knowledge of ageing in the nematode Caenorhabditis elegans and compare the mechanisms of life extension with knowledge from other model organisms.
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Affiliation(s)
- Koen Houthoofd
- Department of Biology, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium
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