1
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Dawson ZD, Sundaramoorthi H, Regmi S, Zhang B, Morrison S, Fielder SM, Zhang JR, Hoang H, Perlmutter DH, Luke CJ, Silverman GA, Pak SC. A fluorescent reporter for rapid assessment of autophagic flux reveals unique autophagy signatures during C. elegans post-embryonic development and identifies compounds that modulate autophagy. AUTOPHAGY REPORTS 2024; 3:2371736. [PMID: 39070663 PMCID: PMC11271720 DOI: 10.1080/27694127.2024.2371736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 06/06/2024] [Accepted: 06/10/2024] [Indexed: 07/30/2024]
Abstract
Autophagy is important for many physiological processes; and disordered autophagy can contribute to the pathogenesis of a broad range of systemic disorders. C. elegans is a useful model organism for studying the genetics of autophagy, however, current methods for studying autophagy are labor-intensive and not readily amenable to high-throughput procedures. Here we describe a fluorescent reporter, GFP::LGG-1::mKate2, which is useful for monitoring autophagic flux in live animals. In the intestine, the fusion protein is processed by endogenous ATG-4 to generate GFP::LGG-1 and mKate2 proteins. We provide data indicating that the GFP:mKate ratio is a suitable readout for measuring cellular autophagic flux. Using this reporter, we measured autophagic flux in L1 larvae to day 7 adult animals. We show that basal autophagic flux is relatively low during larval development but increases markedly in reproductive adults before decreasing with age. Furthermore, we show that wild-type, eat-2, and daf-2 mutant animals have distinct autophagic flux profiles through post-embryonic development. Finally, we demonstrate the utility of this reporter by performing a high-content small molecule screen to identify compounds that alter autophagic flux in C. elegans.
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Affiliation(s)
- Zachary D. Dawson
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Hemalatha Sundaramoorthi
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Suk Regmi
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Bo Zhang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Stephanie Morrison
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Sara M. Fielder
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Jessie R. Zhang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Hieu Hoang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - David H. Perlmutter
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Cliff J. Luke
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Gary A. Silverman
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
| | - Stephen C. Pak
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, Washington63110, USA
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2
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Hofer SJ, Carmona‐Gutierrez D, Mueller MI, Madeo F. The ups and downs of caloric restriction and fasting: from molecular effects to clinical application. EMBO Mol Med 2022; 14:e14418. [PMID: 34779138 PMCID: PMC8749464 DOI: 10.15252/emmm.202114418] [Citation(s) in RCA: 109] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 10/05/2021] [Accepted: 10/08/2021] [Indexed: 12/15/2022] Open
Abstract
Age-associated diseases are rising to pandemic proportions, exposing the need for efficient and low-cost methods to tackle these maladies at symptomatic, behavioral, metabolic, and physiological levels. While nutrition and health are closely intertwined, our limited understanding of how diet precisely influences disease often precludes the medical use of specific dietary interventions. Caloric restriction (CR) has approached clinical application as a powerful, yet simple, dietary modulation that extends both life- and healthspan in model organisms and ameliorates various diseases. However, due to psychological and social-behavioral limitations, CR may be challenging to implement into real life. Thus, CR-mimicking interventions have been developed, including intermittent fasting, time-restricted eating, and macronutrient modulation. Nonetheless, possible side effects of CR and alternatives thereof must be carefully considered. We summarize key concepts and differences in these dietary interventions in humans, discuss their molecular effects, and shed light on advantages and disadvantages.
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Affiliation(s)
- Sebastian J Hofer
- Institute of Molecular BiosciencesNAWI GrazUniversity of GrazGrazAustria
- BioHealth GrazGrazAustria
- BioTechMed GrazGrazAustria
| | | | - Melanie I Mueller
- Institute of Molecular BiosciencesNAWI GrazUniversity of GrazGrazAustria
| | - Frank Madeo
- Institute of Molecular BiosciencesNAWI GrazUniversity of GrazGrazAustria
- BioHealth GrazGrazAustria
- BioTechMed GrazGrazAustria
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3
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Wang C, Haas M, Yeo SK, Sebti S, Fernández ÁF, Zou Z, Levine B, Guan JL. Enhanced autophagy in Becn1F121A/F121A knockin mice counteracts aging-related neural stem cell exhaustion and dysfunction. Autophagy 2021; 18:409-422. [PMID: 34101533 DOI: 10.1080/15548627.2021.1936358] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Macroautophagy/autophagy is emerging as a major pathway that regulates both aging and stem cell function. Previous studies have demonstrated a positive correlation of autophagy with longevity; however, these studies did not directly address the consequence of altered autophagy in stem cells during aging. In this study, we used Becn1F121A/F121A knockin mice (designated as Becn1 KI mice) with the F121A allele in the autophagy gene Becn1 to investigate the consequences of enhanced autophagy in postnatal neural stem cells (NSCs) during aging. We found that increased autophagy protected NSCs from exhaustion and promoted neurogenesis in old (≥18-months-old) mice compared with age-matched wild-type (WT) mice, although it did not affect NSCs in young (3-months-old) mice. After pharmacologically-induced elimination of proliferative cells in the subventricular zone (SVZ), there was enhanced re-activation of quiescent NSCs in old Becn1 KI mice as compared to those in WT mice, with more efficient exit from quiescent status to generate proliferative cells and neuroblasts. Moreover, there was also improved maintenance and increased neuronal differentiation of NSCs isolated from the SVZ of old Becn1 KI mice in in vitro assays. Lastly, the increased neurogenesis in Becn1 KI mice was associated with better olfactory function in aged animals. Together, our results suggest a protective role of increased autophagy in aging NSCs, which may help the development of novel strategies to treat age-related neurodegeneration.
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Affiliation(s)
- Chenran Wang
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Michael Haas
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Syn Kok Yeo
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Salwa Sebti
- Center for Autophagy Research, Department of Internal Medicine, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Álvaro F Fernández
- Center for Autophagy Research, Department of Internal Medicine, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Zhongju Zou
- Center for Autophagy Research, Department of Internal Medicine, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Beth Levine
- Center for Autophagy Research, Department of Internal Medicine, Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jun-Lin Guan
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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4
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Qiu Y, Liu Y, Li Y, Li G, Wang D. Effect of chronic exposure to nanopolystyrene on nematode Caenorhabditis elegans. CHEMOSPHERE 2020; 256:127172. [PMID: 32470744 DOI: 10.1016/j.chemosphere.2020.127172] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Nanoplastic exposure could cause toxicity to Caenorhabditis elegans at various aspects. Nevertheless, the effects of chronic exposure to nanoplastics remain largely unclear in nematodes. In this study, we employed C. elegans as an animal model to determine the effects of nanopolystyrene (30 nm) exposure from adult day-1 for 8-day. After the exposure, only 1000 μg/L nanopolystyrene reduced the lifespan. In contrast, nanopolystyrene ≥1 μg/L decreased locomotion behavior and activated oxidative stress. Meanwhile, in 10 μg/L nanopolystyrene exposed nematodes, both expression of SOD-3, a Mn-SOD, and autophagy induction as indicated by LGG-1:GFP expression were significantly increased. RNAi knockdown of daf-2 encoding an insulin receptor enhanced the autophagy induction, and RNAi knockdown of daf-16 encoding a FOXO transcriptional factor in insulin signaling pathway suppressed the autophagy induction in 10 μg/L nanopolystyrene exposed nematodes. Moreover, DAF-16 acted upstream of LGG-1, an ortholog of Atg8/LC3, to regulate the toxicity of nanopolystyrene toxicity in inducing ROS production and in decreasing locomotion behavior at adult day-9. Our data implied the potential toxicity of chronic exposure to nanoplastics at predicted environmental concentrations on organisms.
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Affiliation(s)
- Yuexiu Qiu
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Medical School, Southeast University, Nanjing, 210009, China
| | - Yaqi Liu
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Medical School, Southeast University, Nanjing, 210009, China
| | - Yunhui Li
- School of Public Health, Southeast University, Nanjing, 210009, China.
| | - Guojun Li
- Beijing Research Center for Prevention Medicine, Beijing, 100013, China.
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Medical School, Southeast University, Nanjing, 210009, China; Shenzhen Ruipuxun Academy for Stem Cell & Regenerative Medicine, Shenzhen, 518122, China.
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5
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Wong SQ, Kumar AV, Mills J, Lapierre LR. C. elegans to model autophagy-related human disorders. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 172:325-373. [PMID: 32620247 DOI: 10.1016/bs.pmbts.2020.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autophagy is a highly conserved degradation process that clears damaged intracellular macromolecules and organelles in order to maintain cellular health. Dysfunctional autophagy is fundamentally linked to the development of various human disorders and pathologies. The use of the nematode Caenorhabditis elegans as a model system to study autophagy has improved our understanding of its regulation and function in organismal physiology. Here, we review the genetic, functional, and regulatory conservation of the autophagy pathway in C. elegans and we describe tools to quantify and study the autophagy process in this incredibly useful model organism. We further discuss how these nematodes have been modified to model autophagy-related human diseases and underscore the important insights obtained from such models. Altogether, we highlight the strengths of C. elegans as an exceptional tool to understand the genetic and molecular foundations underlying autophagy-related human diseases.
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Affiliation(s)
- Shi Quan Wong
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States
| | - Anita V Kumar
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States
| | - Joslyn Mills
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States
| | - Louis R Lapierre
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States.
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6
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Liu W, Wang Z, Xia Y, Kuang H, Liu S, Li L, Tang C, Yin D. The balance of apoptosis and autophagy via regulation of the AMPK signal pathway in aging rat striatum during regular aerobic exercise. Exp Gerontol 2019; 124:110647. [PMID: 31255733 DOI: 10.1016/j.exger.2019.110647] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 06/25/2019] [Accepted: 06/26/2019] [Indexed: 12/28/2022]
Abstract
The objective was to analyze the effects of aerobic exercise on aging striatum stress resistance, and the adaptive mechanisms related to neurodegenerative diseases, and the occurrence, and development of neural degeneration. The 10-weeks of regular moderate-intensity aerobic exercise intervention were carried out in the aerobic exercise runner Sprague-Dawley rats. Apoptotic nuclei appeared in the striatum of aged rats, showing a tendency to relate to aging. The apoptotic index of the striatum in young, middle-aged, and old-aged rats of the aerobic exercise groups increased by 205.56%, 57%, and 68.24%. Autophagy markers Beclin l and LC 3-II expression, AMPKα1 and pAMPKα1 expression increased significantly in all age-exercise groups. The ratio of AMPKα1/pAMPKα1 increased after exercise, and the tendency of exercise to alter autophagy and cell apoptosis increased with aging. Then SirT2 mRNA was significantly upregulated in the aerobic exercise runner groups. In conclusion, we showed that the balance of autophagy and apoptosis were closely regulated by regular aerobic exercise, which affected the development of aging, and via regulation of the AMPK/SirT2 signaling pathway.
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Affiliation(s)
- Wenfeng Liu
- Hunan Provincial Key Laboratory of Physical Fitness and Sports Rehabilitation, Hunan Normal University, Changsha, Hunan 410012, China; Department of Experimental and Clinical Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA.
| | - Zhiyuan Wang
- Hunan Provincial Key Laboratory of Physical Fitness and Sports Rehabilitation, Hunan Normal University, Changsha, Hunan 410012, China
| | - Yan Xia
- Hunan Provincial Key Laboratory of Physical Fitness and Sports Rehabilitation, Hunan Normal University, Changsha, Hunan 410012, China
| | - Heyu Kuang
- Hunan Provincial Key Laboratory of Physical Fitness and Sports Rehabilitation, Hunan Normal University, Changsha, Hunan 410012, China
| | - Shaopeng Liu
- Hunan Provincial Key Laboratory of Physical Fitness and Sports Rehabilitation, Hunan Normal University, Changsha, Hunan 410012, China
| | - Li Li
- School of Health & Kinesiology, Georgia Southern University, Statesboro, GA 30460, USA
| | - Changfa Tang
- Hunan Provincial Key Laboratory of Physical Fitness and Sports Rehabilitation, Hunan Normal University, Changsha, Hunan 410012, China.
| | - Dazhong Yin
- Hunan Provincial Key Laboratory of Physical Fitness and Sports Rehabilitation, Hunan Normal University, Changsha, Hunan 410012, China; Qingyuan People's Hospital, the Sixth Affiliated Hospital, Guangzhou Medical University, Guangzhou, Guangdong 511500, China.
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7
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Minnerly J, Zhang J, Parker T, Kaul T, Jia K. The cell non-autonomous function of ATG-18 is essential for neuroendocrine regulation of Caenorhabditis elegans lifespan. PLoS Genet 2017; 13:e1006764. [PMID: 28557996 PMCID: PMC5469504 DOI: 10.1371/journal.pgen.1006764] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 06/13/2017] [Accepted: 04/18/2017] [Indexed: 12/11/2022] Open
Abstract
Dietary restriction (DR) and reduced insulin growth factor (IGF) signaling extend lifespan in Caenorhabditis elegans and other eukaryotic organisms. Autophagy, an evolutionarily conserved lysosomal degradation pathway, has emerged as a central pathway regulated by various longevity signals including DR and IGF signaling in promoting longevity in a variety of eukaryotic organisms. However, the mechanism remains unclear. Here we show that the autophagy protein ATG-18 acts cell non-autonomously in neuronal and intestinal tissues to maintain C. elegans wildtype lifespan and to respond to DR and IGF-mediated longevity signaling. Moreover, ATG-18 activity in chemosensory neurons that are involved in food detection sufficiently mediates the effect of these longevity pathways. Additionally, ATG-18-mediated cell non-autonomous signaling depends on the release of neurotransmitters and neuropeptides. Interestingly, our data suggest that neuronal and intestinal ATG-18 acts in parallel and converges on unidentified neurons that secrete neuropeptides to regulate C. elegans lifespan through the transcription factor DAF-16/FOXO in response to reduced IGF signaling.
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Affiliation(s)
- Justin Minnerly
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Jiuli Zhang
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Thomas Parker
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Tiffany Kaul
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, United States of America
- * E-mail:
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8
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Kinetics and specificity of paternal mitochondrial elimination in Caenorhabditis elegans. Nat Commun 2016; 7:12569. [PMID: 27581092 PMCID: PMC5025750 DOI: 10.1038/ncomms12569] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 07/13/2016] [Indexed: 12/22/2022] Open
Abstract
In most eukaryotes, mitochondria are inherited maternally. The autophagy process is critical for paternal mitochondrial elimination (PME) in Caenorhabditis elegans, but how paternal mitochondria, but not maternal mitochondria, are selectively targeted for degradation is poorly understood. Here we report that mitochondrial dynamics have a profound effect on PME. A defect in fission of paternal mitochondria delays PME, whereas a defect in fusion of paternal mitochondria accelerates PME. Surprisingly, a defect in maternal mitochondrial fusion delays PME, which is reversed by a fission defect in maternal mitochondria or by increasing maternal mitochondrial membrane potential using oligomycin. Electron microscopy and tomography analyses reveal that a proportion of maternal mitochondria are compromised when they fail to fuse normally, leading to their competition for the autophagy machinery with damaged paternal mitochondria and delayed PME. Our study indicates that mitochondrial dynamics play a critical role in regulating both the kinetics and the specificity of PME. Autophagy mediates the degradation of paternal mitochondria after fertilization in C. elegans to ensure that mitochondria are inherited maternally. Here the authors show that mitochondrial dynamics is critical for the selectivity and kinetics of paternal mitochondrial elimination.
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9
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Zhou Q, Li H, Li H, Nakagawa A, Lin JLJ, Lee ES, Harry BL, Skeen-Gaar RR, Suehiro Y, William D, Mitani S, Yuan HS, Kang BH, Xue D. Mitochondrial endonuclease G mediates breakdown of paternal mitochondria upon fertilization. Science 2016; 353:394-9. [PMID: 27338704 DOI: 10.1126/science.aaf4777] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Accepted: 06/15/2016] [Indexed: 12/26/2022]
Abstract
Mitochondria are inherited maternally in most animals, but the mechanisms of selective paternal mitochondrial elimination (PME) are unknown. While examining fertilization in Caenorhabditis elegans, we observed that paternal mitochondria rapidly lose their inner membrane integrity. CPS-6, a mitochondrial endonuclease G, serves as a paternal mitochondrial factor that is critical for PME. We found that CPS-6 relocates from the intermembrane space of paternal mitochondria to the matrix after fertilization to degrade mitochondrial DNA. It acts with maternal autophagy and proteasome machineries to promote PME. Loss of cps-6 delays breakdown of mitochondrial inner membranes, autophagosome enclosure of paternal mitochondria, and PME. Delayed removal of paternal mitochondria causes increased embryonic lethality, demonstrating that PME is important for normal animal development. Thus, CPS-6 functions as a paternal mitochondrial degradation factor during animal development.
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Affiliation(s)
- Qinghua Zhou
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Haimin Li
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Hanzeng Li
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA. Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309, USA
| | - Akihisa Nakagawa
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Jason L J Lin
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Eui-Seung Lee
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Brian L Harry
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA. Medical Scientist Training Program, University of Colorado, Aurora, CO 80045, USA
| | - Riley Robert Skeen-Gaar
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
| | - Yuji Suehiro
- Department of Physiology, Tokyo Women's Medical University, School of Medicine and CREST, Japan Science and Technology Agency, Tokyo 162-8666, Japan
| | - Donna William
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Shohei Mitani
- Department of Physiology, Tokyo Women's Medical University, School of Medicine and CREST, Japan Science and Technology Agency, Tokyo 162-8666, Japan
| | - Hanna S Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Byung-Ho Kang
- School of Life Sciences, Centre for Cell and Developmental Biology and State Key Laboratory of Agrobiotechnology, Chinese University of Hong Kong, Hong Kong, China.
| | - Ding Xue
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA.
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10
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Zhou X, Yang C, Liu Y, Li P, Yang H, Dai J, Qu R, Yuan L. Lipid rafts participate in aberrant degradative autophagic-lysosomal pathway of amyloid-beta peptide in Alzheimer's disease. Neural Regen Res 2014; 9:92-100. [PMID: 25206748 PMCID: PMC4146310 DOI: 10.4103/1673-5374.125335] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2013] [Indexed: 11/04/2022] Open
Abstract
Amyloid-beta peptide is the main component of amyloid plaques, which are found in Alzheimer's disease. The generation and deposition of amyloid-beta is one of the crucial factors for the onset and progression of Alzheimer's disease. Lipid rafts are glycolipid-rich liquid domains of the plasma membrane, where certain types of protein tend to aggregate and intercalate. Lipid rafts are involved in the generation of amyloid-beta oligomers and the formation of amyloid-beta peptides. In this paper, we review the mechanism by which lipid rafts disturb the aberrant degradative autophagic-lysosomal pathway of amyloid-beta, which plays an important role in the pathological process of Alzheimer's disease. Moreover, we describe this mechanism from the view of the Two-system Theory of fasciology and thus, suggest that lipid rafts may be a new target of Alzheimer's disease treatment.
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Affiliation(s)
- Xin Zhou
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
| | - Chun Yang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
| | - Yufeng Liu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
| | - Peng Li
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
| | - Huiying Yang
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
| | - Jingxing Dai
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
| | - Rongmei Qu
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
| | - Lin Yuan
- Department of Human Anatomy, Histology and Embryology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, Guang-dong Province, China
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11
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Curt A, Zhang J, Minnerly J, Jia K. Intestinal autophagy activity is essential for host defense against Salmonella typhimurium infection in Caenorhabditis elegans. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 45:214-218. [PMID: 24674884 DOI: 10.1016/j.dci.2014.03.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2013] [Revised: 03/17/2014] [Accepted: 03/17/2014] [Indexed: 06/03/2023]
Abstract
Salmonella typhimurium infects both intestinal epithelial cells and macrophages. Autophagy is a lysosomal degradation pathway that is present in all eukaryotes. Autophagy has been reported to limit the Salmonella replication in Caenorhabditis elegans and in mammals. However, it is unknown whether intestinal autophagy activity plays a role in host defense against Salmonella infection in C. elegans. In this study, we inhibited the autophagy gene bec-1 in different C. elegans tissues and examined the survival of these animals following Salmonella infection. Here we show that inhibition of the bec-1 gene in the intestine but not in other tissues confers susceptibility to Salmonella infection, which is consistent with recent studies in mice showing that autophagy is involved in clearance of Salmonella in the intestinal epithelial cells. Therefore, the intestinal autophagy activity is essential for host defense against Salmonella infection from C. elegans to mice, perhaps also in humans.
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Affiliation(s)
- Alexander Curt
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Jiuli Zhang
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Justin Minnerly
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA.
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12
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Denzel MS, Storm NJ, Gutschmidt A, Baddi R, Hinze Y, Jarosch E, Sommer T, Hoppe T, Antebi A. Hexosamine pathway metabolites enhance protein quality control and prolong life. Cell 2014; 156:1167-1178. [PMID: 24630720 DOI: 10.1016/j.cell.2014.01.061] [Citation(s) in RCA: 169] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 10/29/2013] [Accepted: 01/24/2014] [Indexed: 01/29/2023]
Abstract
Aging entails a progressive decline in protein homeostasis, which often leads to age-related diseases. The endoplasmic reticulum (ER) is the site of protein synthesis and maturation for secreted and membrane proteins. Correct folding of ER proteins requires covalent attachment of N-linked glycan oligosaccharides. Here, we report that increased synthesis of N-glycan precursors in the hexosamine pathway improves ER protein homeostasis and extends lifespan in C. elegans. Addition of the N-glycan precursor N-acetylglucosamine to the growth medium slows aging in wild-type animals and alleviates pathology of distinct neurotoxic disease models. Our data suggest that reduced aggregation of metastable proteins and lifespan extension depend on enhanced ER-associated protein degradation, proteasomal activity, and autophagy. Evidently, hexosamine pathway activation or N-acetylglucosamine supplementation induces distinct protein quality control mechanisms, which may allow therapeutic intervention against age-related and proteotoxic diseases.
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Affiliation(s)
- Martin S Denzel
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany
| | - Nadia J Storm
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany
| | - Aljona Gutschmidt
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50674, Germany; Institute for Genetics, University of Cologne, Zülpicher Strasse 47a, Cologne 50674, Germany
| | - Ruth Baddi
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany
| | - Yvonne Hinze
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany
| | - Ernst Jarosch
- Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Strasse 10, Berlin-Buch 13125, Germany
| | - Thomas Sommer
- Max-Delbrück-Center for Molecular Medicine, Robert-Rössle-Strasse 10, Berlin-Buch 13125, Germany; Humboldt-University Berlin, Institute of Biology, Invalidenstrasse 43, Berlin 10115, Germany
| | - Thorsten Hoppe
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50674, Germany; Institute for Genetics, University of Cologne, Zülpicher Strasse 47a, Cologne 50674, Germany
| | - Adam Antebi
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Strasse 9b, Cologne 50931, Germany; Department of Molecular and Cellular Biology, Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne 50674, Germany.
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13
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Basu S, Rajakaruna S, Reyes B, Van Bockstaele E, Menko AS. Suppression of MAPK/JNK-MTORC1 signaling leads to premature loss of organelles and nuclei by autophagy during terminal differentiation of lens fiber cells. Autophagy 2014; 10:1193-211. [PMID: 24813396 PMCID: PMC4203547 DOI: 10.4161/auto.28768] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although autophagic pathways are essential to developmental processes, many questions still remain regarding the initiation signals that regulate autophagy in the context of differentiation. To address these questions we studied the ocular lens, as the programmed elimination of nuclei and organelles occurs in a precisely regulated spatiotemporal manner to form the organelle-free zone (OFZ), a characteristic essential for vision acuity. Here, we report our discovery that inactivation of MAPK/JNK induces autophagy for formation of the OFZ through its regulation of MTORC1, where MAPK/JNK signaling is required for both MTOR activation and RPTOR/RAPTOR phosphorylation. Autophagy pathway proteins including ULK1, BECN1/Beclin 1, and MAP1LC3B2/LC3B-II were upregulated in the presence of inhibitors to either MAPK/JNK or MTOR, inducing autophagic loss of organelles to form the OFZ. These results reveal that MAPK/JNK is a positive regulator of MTORC1 signaling and its developmentally regulated inactivation provides an inducing signal for the coordinated autophagic removal of nuclei and organelles required for lens function.
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Affiliation(s)
- Subhasree Basu
- Department of Pathology, Anatomy and Cell Biology; Thomas Jefferson University; Philadelphia, PA USA
| | - Suren Rajakaruna
- Department of Pathology, Anatomy and Cell Biology; Thomas Jefferson University; Philadelphia, PA USA
| | - Beverly Reyes
- Department of Neuroscience; Farber Institute for Neuroscience; Thomas Jefferson University; Philadelphia, PA USA
| | - Elisabeth Van Bockstaele
- Department of Neuroscience; Farber Institute for Neuroscience; Thomas Jefferson University; Philadelphia, PA USA
| | - A Sue Menko
- Department of Pathology, Anatomy and Cell Biology; Thomas Jefferson University; Philadelphia, PA USA
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14
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Hale AN, Ledbetter DJ, Gawriluk TR, Rucker EB. Autophagy: regulation and role in development. Autophagy 2014; 9:951-72. [PMID: 24121596 DOI: 10.4161/auto.24273] [Citation(s) in RCA: 266] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Autophagy is an evolutionarily conserved cellular process through which long-lived proteins and damaged organelles are recycled to maintain energy homeostasis. These proteins and organelles are sequestered into a double-membrane structure, or autophagosome, which subsequently fuses with a lysosome in order to degrade the cargo. Although originally classified as a type of programmed cell death, autophagy is more widely viewed as a basic cell survival mechanism to combat environmental stressors. Autophagy genes were initially identified in yeast and were found to be necessary to circumvent nutrient stress and starvation. Subsequent elucidation of mammalian gene counterparts has highlighted the importance of this process to normal development. This review provides an overview of autophagy, the types of autophagy, its regulation and its known impact on development gleaned primarily from murine models.
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Affiliation(s)
- Amber N Hale
- Department of Biology; University of Kentucky; Lexington, KY USA
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15
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Role of protein misfolding and proteostasis deficiency in protein misfolding diseases and aging. Int J Cell Biol 2013; 2013:638083. [PMID: 24348562 PMCID: PMC3855986 DOI: 10.1155/2013/638083] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 10/08/2013] [Accepted: 10/09/2013] [Indexed: 11/29/2022] Open
Abstract
The misfolding, aggregation, and tissue accumulation of proteins are common events in diverse chronic diseases, known as protein misfolding disorders. Many of these diseases are associated with aging, but the mechanism for this connection is unknown. Recent evidence has shown that the formation and accumulation of protein aggregates may be a process frequently occurring during normal aging, but it is unknown whether protein misfolding is a cause or a consequence of aging. To combat the formation of these misfolded aggregates cells have developed complex and complementary pathways aiming to maintain protein homeostasis. These protective pathways include the unfolded protein response, the ubiquitin proteasome system, autophagy, and the encapsulation of damaged proteins in aggresomes. In this paper we review the current knowledge on the role of protein misfolding in disease and aging as well as the implication of deficiencies in the proteostasis cellular pathways in these processes. It is likely that further understanding of the mechanisms involved in protein misfolding and the natural defense pathways may lead to novel strategies for treatment of age-dependent protein misfolding disorders and perhaps aging itself.
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16
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Neal MD, Sodhi CP, Dyer M, Craig BT, Good M, Jia H, Yazji I, Afrazi A, Richardson WM, Beer-Stolz D, Ma C, Prindle T, Grant Z, Branca MF, Ozolek J, Hackam DJ. A critical role for TLR4 induction of autophagy in the regulation of enterocyte migration and the pathogenesis of necrotizing enterocolitis. THE JOURNAL OF IMMUNOLOGY 2013; 190:3541-51. [PMID: 23455503 DOI: 10.4049/jimmunol.1202264] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Necrotizing enterocolitis (NEC) develops in response to elevated TLR4 signaling in the newborn intestinal epithelium and is characterized by TLR4-mediated inhibition of enterocyte migration and reduced mucosal healing. The downstream processes by which TLR4 impairs mucosal healing remain incompletely understood. In other systems, TLR4 induces autophagy, an adaptive response to cellular stress. We now hypothesize that TLR4 induces autophagy in enterocytes and that TLR4-induced autophagy plays a critical role in NEC development. Using mice selectively lacking TLR4 in enterocytes (TLR4(ΔIEC)) and in TLR4-deficient cultured enterocytes, we now show that TLR4 activation induces autophagy in enterocytes. Immature mouse and human intestine showed increased expression of autophagy genes compared with full-term controls, and NEC development in both mouse and human was associated with increased enterocyte autophagy. Importantly, using mice in which we selectively deleted the autophagy gene ATG7 from the intestinal epithelium (ATG7(ΔIEC)), the induction of autophagy was determined to be required for and not merely a consequence of NEC, because ATG7(ΔIEC) mice were protected from NEC development. In defining the mechanisms involved, TLR4-induced autophagy led to impaired enterocyte migration both in vitro and in vivo, which in cultured enterocytes required the induction of RhoA-mediated stress fibers. These findings depart from current dogma in the field by identifying a unique effect of TLR4-induced autophagy within the intestinal epithelium in the pathogenesis of NEC and identify that the negative consequences of autophagy on enterocyte migration play an essential role in its development.
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Affiliation(s)
- Matthew D Neal
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
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17
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Harries LW, Fellows AD, Pilling LC, Hernandez D, Singleton A, Bandinelli S, Guralnik J, Powell J, Ferrucci L, Melzer D. Advancing age is associated with gene expression changes resembling mTOR inhibition: evidence from two human populations. Mech Ageing Dev 2012; 133:556-62. [PMID: 22813852 DOI: 10.1016/j.mad.2012.07.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 06/25/2012] [Accepted: 07/07/2012] [Indexed: 12/21/2022]
Abstract
Interventions which inhibit TOR activity (including rapamycin and caloric restriction) lead to downstream gene expression changes and increased lifespan in laboratory models. However, the role of mTOR signaling in human aging is unclear. We tested the expression of mTOR-related transcripts in two independent study cohorts; the InCHIANTI population study of aging and the San Antonio Family Heart Study (SAFHS). Expression of 27/56 (InCHIANTI) and 19/44 (SAFHS) genes were associated with age after correction for multiple testing. 8 genes were robustly associated with age in both cohorts. Genes involved in insulin signaling (PTEN, PI3K, PDK1), ribosomal biogenesis (S6K), lipid metabolism (SREBF1), cellular apoptosis (SGK1), angiogenesis (VEGFB), insulin production and sensitivity (FOXO), cellular stress response (HIF1A) and cytoskeletal remodeling (PKC) were inversely correlated with age, whereas genes relating to inhibition of ribosomal components (4EBP1) and inflammatory mediators (STAT3) were positively associated with age in one or both datasets. We conclude that the expression of mTOR-related transcripts is associated with advancing age in humans. Changes seen are broadly similar to mTOR inhibition interventions associated with increased lifespan in animals. Work is needed to establish whether these changes are predictive of human longevity and whether further mTOR inhibition would be beneficial in older people.
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Affiliation(s)
- Lorna W Harries
- Institute of Biomedical and Clinical Sciences, Peninsula College of Medicine and Dentistry, University of Exeter, Exeter EX2 5DW, UK
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18
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Porta-de-la-Riva M, Fontrodona L, Villanueva A, Cerón J. Basic Caenorhabditis elegans methods: synchronization and observation. J Vis Exp 2012:e4019. [PMID: 22710399 DOI: 10.3791/4019] [Citation(s) in RCA: 205] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Research into the molecular and developmental biology of the nematode Caenorhabditis elegans was begun in the early seventies by Sydney Brenner and it has since been used extensively as a model organism. C. elegans possesses key attributes such as simplicity, transparency and short life cycle that have made it a suitable experimental system for fundamental biological studies for many years. Discoveries in this nematode have broad implications because many cellular and molecular processes that control animal development are evolutionary conserved. C. elegans life cycle goes through an embryonic stage and four larval stages before animals reach adulthood. Development can take 2 to 4 days depending on the temperature. In each of the stages several characteristic traits can be observed. The knowledge of its complete cell lineage together with the deep annotation of its genome turn this nematode into a great model in fields as diverse as the neurobiology, aging, stem cell biology and germ line biology. An additional feature that makes C. elegans an attractive model to work with is the possibility of obtaining populations of worms synchronized at a specific stage through a relatively easy protocol. The ease of maintaining and propagating this nematode added to the possibility of synchronization provide a powerful tool to obtain large amounts of worms, which can be used for a wide variety of small or high-throughput experiments such as RNAi screens, microarrays, massive sequencing, immunoblot or in situ hybridization, among others. Because of its transparency, C. elegans structures can be distinguished under the microscope using Differential Interference Contrast microscopy, also known as Nomarski microscopy. The use of a fluorescent DNA binder, DAPI (4',6-diamidino-2-phenylindole), for instance, can lead to the specific identification and localization of individual cells, as well as subcellular structures/defects associated to them.
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Rongo C. Epidermal growth factor and aging: a signaling molecule reveals a new eye opening function. Aging (Albany NY) 2012; 3:896-905. [PMID: 21931179 PMCID: PMC3227454 DOI: 10.18632/aging.100384] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Epidermal Growth Factor (EGF) is known for its role in promoting cell division and cellular differentiation in developing animals, but we know surprising little about what EGF does in vivo in mature adult animals. Here I review EGF signaling, emphasizing several recent studies that uncovered an unexpected role for EGF in promoting longevity and healthspan in mature adult C. elegans. EGF, acting through phospholipase Cγ and the IP3 receptor signaling, maintains pharyngeal and body wall muscle function in aging adults, and delays the accumulation of lipofuscin-enriched aging pigments within intestinal cells. EGF also acts through the Ras/ERK pathway to regulate protein homeostasis by promoting the expression of antioxidant genes, stimulating the activity of the Ubiquitin Proteasome System (UPS), and repressing the expression of small heat shock protein chaperones. The effects of EGF signaling on lifespan are largely independent of Insulin/IGF-like Signaling (IIS), as the effects of EGF signaling mutants on lifespan and heathspan are not affected by mutations in the DAF-2 insulin receptor or the DAF-16 FOXO transcription factor. Nevertheless, these two signal pathways have multiple points of overlap, coordination, and cross regulation. I propose that the IIS and EGF signaling pathways respond to environment and to developmental timing, respectively, so as to coordinate the appropriate physiological strategy that cells use to maintain protein homeostasis.
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Affiliation(s)
- Christopher Rongo
- The Waksman Institute, Department of Genetics, Rutgers The State University of New Jersey, Piscataway, New Jersey, USA.
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20
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The role of autophagy in genetic pathways influencing ageing. Biogerontology 2011; 12:377-86. [PMID: 21347677 DOI: 10.1007/s10522-011-9324-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 02/13/2011] [Indexed: 12/25/2022]
Abstract
Autophagy is a conserved cellular degradation pathway for the breakdown of cytosolic macromolecules and organelles. Constitutive autophagy has a housekeeping role and is essential for survival, development and metabolic regulation. Autophagy is also responsive to stress and can degrade damaged proteins and organelles, oxidized lipids and intracellular pathogens. Defects in the autophagic degradation system are linked to disease pathogenesis and ageing. Different signalling pathways converge on autophagy to regulate lifespan in diverse organisms. We discuss recent findings that provide insight into the cross-talk between this critical regulator of metabolic homeostasis and molecular mechanisms that promote longevity.
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