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Zhang A, Meecham-Garcia G, Nguyen Hong C, Xie P, Kern CC, Zhang B, Chapman H, Gems D. Characterization of Effects of mTOR Inhibitors on Aging in Caenorhabditis elegans. J Gerontol A Biol Sci Med Sci 2024; 79:glae196. [PMID: 39150882 PMCID: PMC11374883 DOI: 10.1093/gerona/glae196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Indexed: 08/18/2024] Open
Abstract
Pharmacological inhibition of the mechanistic target of rapamycin (mTOR) signaling pathway with rapamycin can extend lifespan in several organisms. Although this includes the nematode Caenorhabditis elegans, effects in this species are relatively weak and sometimes difficult to reproduce. Here we test effects of drug dosage and timing of delivery to establish the upper limits of its capacity to extend life, and investigate drug effects on age-related pathology and causes of mortality. Liposome-mediated rapamycin treatment throughout adulthood showed a dose-dependent effect, causing a maximal 21.9% increase in mean lifespan, but shortening of lifespan at the highest dose, suggesting drug toxicity. Rapamycin treatment of larvae delayed development, weakly reduced fertility and modestly extended lifespan. By contrast, treatment initiated later in life robustly increased lifespan, even from Day 16 (or ~70 years in human terms). The rapalog temsirolimus extended lifespan similarly to rapamycin, but effects of everolimus were weaker. As in mouse, rapamycin had mixed effects on age-related pathologies, inhibiting one (uterine tumor growth) but not several others, suggesting a segmental antigeroid effect. These findings should usefully inform future experimental studies with rapamycin and rapalogs in C. elegans.
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Affiliation(s)
- Aihan Zhang
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Gadea Meecham-Garcia
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Chiminh Nguyen Hong
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Peiyun Xie
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Carina C Kern
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Bruce Zhang
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Hannah Chapman
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
| | - David Gems
- Institute of Healthy Ageing, and Research Department of Genetics, Evolution and Environment, University College London, London, UK
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2
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Ghosh A, Singh J. Translation initiation or elongation inhibition triggers contrasting effects on Caenorhabditis elegans survival during pathogen infection. mBio 2024:e0248524. [PMID: 39347574 DOI: 10.1128/mbio.02485-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Accepted: 09/11/2024] [Indexed: 10/01/2024] Open
Abstract
Diverse microbial pathogens are known to attenuate host protein synthesis. Consequently, the host mounts a defense response against protein translation inhibition, leading to increased transcript levels of immune genes. The seemingly paradoxical upregulation of immune gene transcripts in response to blocked protein synthesis suggests that the defense mechanism against translation inhibition may not universally benefit host survival. However, a comprehensive assessment of host survival on pathogens upon blockage of different stages of protein synthesis is currently lacking. Here, we investigate the impact of knockdown of various translation initiation and elongation factors on the survival of Caenorhabditis elegans exposed to Pseudomonas aeruginosa. Intriguingly, we observe opposing effects on C. elegans survival depending on whether translation initiation or elongation is inhibited. While translation initiation inhibition enhances survival, elongation inhibition decreases it. Transcriptomic studies reveal that translation initiation inhibition activates a bZIP transcription factor ZIP-2-dependent innate immune response that protects C. elegans from P. aeruginosa infection. In contrast, inhibiting translation elongation triggers both ZIP-2-dependent and ZIP-2-independent immune responses that, while effective in clearing the infection, are detrimental to the host. Thus, our findings reveal the opposing roles of translation initiation and elongation inhibition in C. elegans survival during P. aeruginosa infection, highlighting distinct transcriptional reprogramming that may underlie these differences. IMPORTANCE Several microbial pathogens target host protein synthesis machinery, potentially limiting the innate immune responses of the host. In response, hosts trigger a defensive response, elevating immune gene transcripts. This counterintuitive response can have either beneficial or harmful effects on host survival. In this study, we conduct a comprehensive analysis of the impact of knocking down various translation initiation and elongation factors on the survival of Caenorhabditis elegans exposed to Pseudomonas aeruginosa. Intriguingly, inhibiting initiation and elongation factors has contrasting effects on C. elegans survival. Inhibiting translation initiation activates immune responses that protect the host from bacterial infection, while inhibiting translation elongation induces aberrant immune responses that, although clear the infection, are detrimental to the host. Our study reveals divergent roles of translation initiation and elongation inhibition in C. elegans survival during P. aeruginosa infection and identifies differential transcriptional reprogramming that could underlie these differences.
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Affiliation(s)
- Annesha Ghosh
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, Punjab, India
| | - Jogender Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, Punjab, India
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3
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Al-Refaie N, Padovani F, Hornung J, Pudelko L, Binando F, Del Carmen Fabregat A, Zhao Q, Towbin BD, Cenik ES, Stroustrup N, Padeken J, Schmoller KM, Cabianca DS. Fasting shapes chromatin architecture through an mTOR/RNA Pol I axis. Nat Cell Biol 2024:10.1038/s41556-024-01512-w. [PMID: 39300311 DOI: 10.1038/s41556-024-01512-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 08/19/2024] [Indexed: 09/22/2024]
Abstract
Chromatin architecture is a fundamental mediator of genome function. Fasting is a major environmental cue across the animal kingdom, yet how it impacts three-dimensional (3D) genome organization is unknown. Here we show that fasting induces an intestine-specific, reversible and large-scale spatial reorganization of chromatin in Caenorhabditis elegans. This fasting-induced 3D genome reorganization requires inhibition of the nutrient-sensing mTOR pathway, acting through the regulation of RNA Pol I, but not Pol II nor Pol III, and is accompanied by remodelling of the nucleolus. By uncoupling the 3D genome configuration from the animal's nutritional status, we find that the expression of metabolic and stress-related genes increases when the spatial reorganization of chromatin occurs, showing that the 3D genome might support the transcriptional response in fasted animals. Our work documents a large-scale chromatin reorganization triggered by fasting and reveals that mTOR and RNA Pol I shape genome architecture in response to nutrients.
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Affiliation(s)
- Nada Al-Refaie
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
- Faculty of Medicine, Ludwig-Maximilians Universität München, Munich, Germany
| | - Francesco Padovani
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Johanna Hornung
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Lorenz Pudelko
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
- Faculty of Medicine, Ludwig-Maximilians Universität München, Munich, Germany
| | - Francesca Binando
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Andrea Del Carmen Fabregat
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Qiuxia Zhao
- Department of Molecular Biosciences, University of Texas Austin, Austin, TX, USA
| | | | - Elif Sarinay Cenik
- Department of Molecular Biosciences, University of Texas Austin, Austin, TX, USA
| | - Nicholas Stroustrup
- Centre for Genomic Regulation, The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Jan Padeken
- Institute of Molecular Biology, Mainz, Germany
| | - Kurt M Schmoller
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Daphne S Cabianca
- Institute of Functional Epigenetics, Helmholtz Zentrum München, Neuherberg, Germany.
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4
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Ortega-Molina A, Lebrero-Fernández C, Sanz A, Calvo-Rubio M, Deleyto-Seldas N, de Prado-Rivas L, Plata-Gómez AB, Fernández-Florido E, González-García P, Vivas-García Y, Sánchez García E, Graña-Castro O, Price NL, Aroca-Crevillén A, Caleiras E, Monleón D, Borrás C, Casanova-Acebes M, de Cabo R, Efeyan A. A mild increase in nutrient signaling to mTORC1 in mice leads to parenchymal damage, myeloid inflammation and shortened lifespan. NATURE AGING 2024; 4:1102-1120. [PMID: 38849535 PMCID: PMC11333293 DOI: 10.1038/s43587-024-00635-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/25/2024] [Indexed: 06/09/2024]
Abstract
The mechanistic target of rapamycin complex 1 controls cellular anabolism in response to growth factor signaling and to nutrient sufficiency signaled through the Rag GTPases. Inhibition of mTOR reproducibly extends longevity across eukaryotes. Here we report that mice that endogenously express active mutant variants of RagC exhibit multiple features of parenchymal damage that include senescence, expression of inflammatory molecules, increased myeloid inflammation with extensive features of inflammaging and a ~30% reduction in lifespan. Through bone marrow transplantation experiments, we show that myeloid cells are abnormally activated by signals emanating from dysfunctional RagC-mutant parenchyma, causing neutrophil extravasation that inflicts additional inflammatory damage. Therapeutic suppression of myeloid inflammation in aged RagC-mutant mice attenuates parenchymal damage and extends survival. Together, our findings link mildly increased nutrient signaling to limited lifespan in mammals, and support a two-component process of parenchymal damage and myeloid inflammation that together precipitate a time-dependent organ deterioration that limits longevity.
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Affiliation(s)
- Ana Ortega-Molina
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
- Metabolism in cancer and aging Laboratory, Immune System Development And Function Department, Centro de Biología Molecular Severo Ochoa (CBM), Madrid, Spain.
| | - Cristina Lebrero-Fernández
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- Metabolism in cancer and aging Laboratory, Immune System Development And Function Department, Centro de Biología Molecular Severo Ochoa (CBM), Madrid, Spain
| | - Alba Sanz
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Miguel Calvo-Rubio
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Nerea Deleyto-Seldas
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Lucía de Prado-Rivas
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Ana Belén Plata-Gómez
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Elena Fernández-Florido
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | | | - Yurena Vivas-García
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Elena Sánchez García
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Osvaldo Graña-Castro
- Bioinformatics Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
- Institute of Applied Molecular Medicine (IMMA-Nemesio Díez), Department of Basic Medical Sciences, School of Medicine, San Pablo-CEU University, CEU Universities, Boadilla del Monte, Madrid, Spain
| | - Nathan L Price
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Alejandra Aroca-Crevillén
- Cardiovascular Regeneration Program, Centro Nacional de Investigaciones Cardiovasculares, Madrid, Spain
| | - Eduardo Caleiras
- Histopathology Unit, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Daniel Monleón
- Department of Pathology, University of Valencia, Valencia, Spain; Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable-Instituto de Salud Carlos III (CIBERFES-ISCIII), Institute of Health Research-INCLIVA, Valencia, Spain
| | - Consuelo Borrás
- Freshage Research Group, Department of Physiology, Faculty of Medicine, University of Valencia, Centro de Investigación Biomédica en Red Fragilidad y Envejecimiento Saludable-Instituto de Salud Carlos III (CIBERFES-ISCIII), MiniAging Research Group, Institute of Health Research-INCLIVA, Valencia, Spain
| | - María Casanova-Acebes
- Cancer Immunity Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging (NIA), National Institutes of Health (NIH), Baltimore, MD, USA
| | - Alejo Efeyan
- Metabolism and Cell Signaling Laboratory, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
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5
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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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [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, MO 63110, USA
| | - Hemalatha Sundaramoorthi
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Suk Regmi
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Bo Zhang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Stephanie Morrison
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Sara M. Fielder
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Jessie R. Zhang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Hieu Hoang
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - David H. Perlmutter
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
| | - Cliff J. Luke
- Department of Pediatrics, Washington University in St Louis School of Medicine, St Louis, MO 63110, USA
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6
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Malik Y, Goncalves Silva I, Diazgranados RR, Selman C, Alic N, Tullet JM. Timing of TORC1 inhibition dictates Pol III involvement in Caenorhabditis elegans longevity. Life Sci Alliance 2024; 7:e202402735. [PMID: 38740431 DOI: 10.26508/lsa.202402735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/16/2024] Open
Abstract
Organismal growth and lifespan are inextricably linked. Target of Rapamycin (TOR) signalling regulates protein production for growth and development, but if reduced, extends lifespan across species. Reduction in the enzyme RNA polymerase III, which transcribes tRNAs and 5S rRNA, also extends longevity. Here, we identify a temporal genetic relationship between TOR and Pol III in Caenorhabditis elegans, showing that they collaborate to regulate progeny production and lifespan. Interestingly, the lifespan interaction between Pol III and TOR is only revealed when TOR signaling is reduced, specifically in adulthood, demonstrating the importance of timing to control TOR regulated developmental versus adult programs. In addition, we show that Pol III acts in C. elegans muscle to promote both longevity and healthspan and that reducing Pol III even in late adulthood is sufficient to extend lifespan. This demonstrates the importance of Pol III for lifespan and age-related health in adult C. elegans.
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Affiliation(s)
- Yasir Malik
- https://ror.org/00xkeyj56 Division of Natural Sciences, School of Biosciences, University of Kent, Canterbury, Kent
| | - Isabel Goncalves Silva
- https://ror.org/00xkeyj56 Division of Natural Sciences, School of Biosciences, University of Kent, Canterbury, Kent
| | - Rene Rivera Diazgranados
- https://ror.org/00xkeyj56 Division of Natural Sciences, School of Biosciences, University of Kent, Canterbury, Kent
| | - Colin Selman
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow, Scotland
| | - Nazif Alic
- UCL Department of Genetics, Evolution & Environment, Institute of Healthy Ageing, London, UK
| | - Jennifer Ma Tullet
- https://ror.org/00xkeyj56 Division of Natural Sciences, School of Biosciences, University of Kent, Canterbury, Kent
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7
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Gao X, Yu J, Zhang L, Shi H, Yan Y, Han Y, Fang M, Liu Y, Wu C, Fan S, Huang C. Mulberrin extends lifespan in Caenorhabditis elegans through detoxification function. J Appl Toxicol 2024; 44:833-845. [PMID: 38291015 DOI: 10.1002/jat.4578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 12/06/2023] [Accepted: 12/27/2023] [Indexed: 02/01/2024]
Abstract
Mulberrin, a naturally occurring flavone found in mulberry and Romulus Mori, exhibits diverse biological functions. Here, we showed that mulberrin extended both the lifespan and healthspan in C. elegans. Moreover, mulberrin increased the worms' resistance to toxicants and activated the expression of detoxification genes. The longevity-promoting effect of mulberrin was attenuated in nuclear hormone receptor (NHR) homologous nhr-8 and daf-12 mutants, indicating that the lifespan extending effects of mulberrin in C. elegans may depend on nuclear hormone receptors NHR-8/DAF-12. Further analyses revealed the potential associations between the longevity effects of mulberrin and the insulin/insulin-like growth factor signaling (IIS) and adenosine 5'-monophosphate-activated protein kinase (AMPK) pathways. Together, our findings suggest that mulberrin may prolong lifespan and healthspan by activating detoxification functions mediated by nuclear receptors.
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Affiliation(s)
- Xiaoyan Gao
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jing Yu
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Lijun Zhang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Hang Shi
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yingxuan Yan
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Yongli Han
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Minglv Fang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Ying Liu
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Chengyuan Wu
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Shengjie Fan
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Cheng Huang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, Shanghai, China
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8
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Gajjar G, Huggins HP, Kim ES, Huang W, Bonnet FX, Updike DL, Keiper BD. Two germ granule eIF4E isoforms reside in different mRNPs to hand off C elegans mRNAs from translational repression to activation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.24.595216. [PMID: 38826235 PMCID: PMC11142241 DOI: 10.1101/2024.05.24.595216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
We studied the function of translation factor eIF4E isoforms in regulating mRNAs in germ cell granules/condensates. Translational control of mRNAs plays an essential role in germ cell gene regulation. Messenger ribonucleoprotein (mRNP) complexes assemble on mRNAs as they move from the nucleus into perinuclear germ granules to exert both positive and negative post-transcriptional regulation in the cytoplasm. In C. elegans , germ granules are surprisingly dynamic mRNP condensates that remodel during development. Two eIF4E isoforms (called IFE-1 and IFE-3), eIF4E-Interacting Proteins (4EIPs), RBPs, DEAD-box helicases, polyadenylated mRNAs, Argonautes and miRNAs all occupy positions in germ granules. Affinity purification of IFE-1 and IFE-3 allowed mass spectrometry and mRNA-Seq to identify the proteins and mRNAs that populate stable eIF4E mRNPs. We find translationally controlled mRNAs (e.g. pos-1, mex-3, spn-4, etc.) enriched in IFE-3 mRNPs, but excluded from IFE-1 mRNPs. These mRNAs also require IFE-1 for efficient translation. The findings support a model in which oocytes and embryos utilize the two eIF4Es for opposite purposes on critically regulated germline mRNAs. Careful colocalization of the eIF4Es with other germ granule components suggests an architecture in which GLH-1, PGL-1 and the IFEs are stratified to facilitate sequential interactions for mRNAs. Biochemical characterization demonstrates opposing yet cooperative roles for IFE-3 and IFE-1 to hand-off of translationally controlled mRNAs from the repressed to the activated state, respectively. The model involves eIF4E mRNPs shuttling mRNAs through nuclear pore-associated granules/condensates to cytoplasmic ribosomes.
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9
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Torzone SK, Breen PC, Cohen NR, Simmons KN, Dowen RH. The TWK-26 potassium channel governs nutrient absorption in the C. elegans intestine. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.06.592787. [PMID: 38766028 PMCID: PMC11100751 DOI: 10.1101/2024.05.06.592787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Ion channels are necessary for proper water and nutrient absorption in the intestine, which supports cellular metabolism and organismal growth. While a role for Na + co-transporters and pumps in intestinal nutrient absorption is well defined, how individual K + uniporters function to maintain ion homeostasis is poorly understood. Using Caenorhabditis elegans , we show that a gain-of-function mutation in twk-26 , which encodes a two-pore domain K + ion channel orthologous to human KCNK3, facilitates nutrient absorption and suppresses the metabolic and developmental defects displayed by impaired intestinal MAP Kinase (MAPK) signaling. Mutations in drl-1 and flr-4, which encode two components of this MAPK pathway, cause severe growth defects, reduced lipid storage, and a dramatic increase in autophagic lysosomes, which mirror dietary restriction phenotypes. Additionally, these MAPK mutants display structural defects of the intestine and an impaired defecation motor program. We find that activation of TWK-26 reverses the dietary restriction-like state of the MAPK mutants by restoring intestinal nutrient absorption without correcting the intestinal bloating or defecation defects. This study provides unique insight into the mechanisms by which intestinal K + ion channels support intestinal metabolic homeostasis.
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10
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Zang X, Wang Q, Zhang H, Zhang Y, Wang Z, Wu Z, Chen D. Knockdown of neuronal DAF-15/Raptor promotes healthy aging in C. elegans. J Genet Genomics 2024; 51:507-516. [PMID: 37951302 DOI: 10.1016/j.jgg.2023.11.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 11/06/2023] [Accepted: 11/06/2023] [Indexed: 11/13/2023]
Abstract
The highly conserved target of rapamycin (TOR) pathway plays an important role in aging across species. Previous studies have established that inhibition of the TOR complex 1 (TORC1) significantly extends lifespan in Caenorhabditiselegans. However, it has not been clear whether TORC1 perturbation affects aging in a spatiotemporal manner. Here, we apply the auxin-inducible degradation tool to knock down endogenous DAF-15, the C. elegans ortholog of regulatory associated protein of TOR (Raptor), to characterize its roles in aging. Global or tissue-specific inhibition of DAF-15 during development results in various growth defects, whereas neuron-specific knockdown of DAF-15 during adulthood significantly extends lifespan and healthspan. The neuronal DAF-15 deficiency-induced longevity requires the intestinal activities of DAF-16/FOXO and PHA-4/FOXA transcription factors, as well as the AAK-2/AMP-activated protein kinase α catalytic subunit. Transcriptome profiling reveals that the neuronal DAF-15 knockdown promotes the expression of genes involved in protection. These findings define the tissue-specific roles of TORC1 in healthy aging and highlight the importance of neuronal modulation of aging.
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Affiliation(s)
- Xiao Zang
- Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining, Zhejiang 314400, China
| | - Qi Wang
- Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining, Zhejiang 314400, China
| | - Hanxin Zhang
- Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China
| | - Yiyan Zhang
- Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining, Zhejiang 314400, China
| | - Zi Wang
- Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China
| | - Zixing Wu
- Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China
| | - Di Chen
- Model Animal Research Center of Medical School, Nanjing University, Nanjing, Jiangsu 210061, China; Zhejiang University-University of Edinburgh Institute, School of Medicine, Zhejiang University, Haining, Zhejiang 314400, China; Department of Colorectal Surgery, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China.
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11
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Huang G, Cong Z, Liu Z, Chen F, Bravo A, Soberón M, Zheng J, Peng D, Sun M. Silencing Ditylenchus destructor cathepsin L-like cysteine protease has negative pleiotropic effect on nematode ontogenesis. Sci Rep 2024; 14:10030. [PMID: 38693283 PMCID: PMC11063044 DOI: 10.1038/s41598-024-60018-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2024] [Accepted: 04/17/2024] [Indexed: 05/03/2024] Open
Abstract
Ditylenchus destructor is a migratory plant-parasitic nematode that severely harms many agriculturally important crops. The control of this pest is difficult, thus efficient strategies for its management in agricultural production are urgently required. Cathepsin L-like cysteine protease (CPL) is one important protease that has been shown to participate in various physiological and pathological processes. Here we decided to characterize the CPL gene (Dd-cpl-1) from D. destructor. Analysis of Dd-cpl-1 gene showed that Dd-cpl-1 gene contains a signal peptide, an I29 inhibitor domain with ERFNIN and GNFD motifs, and a peptidase C1 domain with four conserved active residues, showing evolutionary conservation with other nematode CPLs. RT-qPCR revealed that Dd-cpl-1 gene displayed high expression in third-stage juveniles (J3s) and female adults. In situ hybridization analysis demonstrated that Dd-cpl-1 was expressed in the digestive system and reproductive organs. Silencing Dd-cpl-1 in 1-cell stage eggs of D. destructor by RNAi resulted in a severely delay in development or even in abortive morphogenesis during embryogenesis. The RNAi-mediated silencing of Dd-cpl-1 in J2s and J3s resulted in a developmental arrest phenotype in J3 stage. In addition, silencing Dd-cpl-1 gene expression in female adults led to a 57.43% decrease in egg production. Finally, Dd-cpl-1 RNAi-treated nematodes showed a significant reduction in host colonization and infection. Overall, our results indicate that Dd-CPL-1 plays multiple roles in D. destructor ontogenesis and could serve as a new potential target for controlling D. destructor.
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Affiliation(s)
- Guoqiang Huang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Ziwen Cong
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Zhonglin Liu
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Feng Chen
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Alejandra Bravo
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico
| | - Mario Soberón
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, 62210, Cuernavaca, Morelos, Mexico
| | - Jinshui Zheng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Donghai Peng
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China
- Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Ming Sun
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, China.
- Hubei Hongshan Laboratory, Wuhan, 430070, China.
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12
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Rabeh K, Oubohssaine M, Hnini M. TOR in plants: Multidimensional regulators of plant growth and signaling pathways. JOURNAL OF PLANT PHYSIOLOGY 2024; 294:154186. [PMID: 38330538 DOI: 10.1016/j.jplph.2024.154186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/10/2024]
Abstract
Target Of Rapamycin (TOR) represents a ubiquitous kinase complex that has emerged as a central regulator of cell growth and metabolism in nearly all eukaryotic organisms. TOR is an evolutionarily conserved protein kinase, functioning as a central signaling hub that integrates diverse internal and external cues to regulate a multitude of biological processes. These processes collectively exert significant influence on plant growth, development, nutrient assimilation, photosynthesis, fruit ripening, and interactions with microorganisms. Within the plant domain, the TOR complex comprises three integral components: TOR, RAPTOR, and LST8. This comprehensive review provides insights into various facets of the TOR protein, encompassing its origin, structure, function, and the regulatory and signaling pathways operative in photosynthetic organisms. Additionally, we explore future perspectives related to this pivotal protein kinase.
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Affiliation(s)
- Karim Rabeh
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
| | - Malika Oubohssaine
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco
| | - Mohamed Hnini
- Microbiology and Molecular Biology Team, Center of Plant and Microbial Biotechnologies, Biodiversity and Environment, Faculty of Sciences, Mohammed V University, Rabat, Morocco
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13
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Schmeisser K, Kaptan D, Raghuraman BK, Shevchenko A, Rodenfels J, Penkov S, Kurzchalia TV. Mobilization of cholesterol induces the transition from quiescence to growth in Caenorhabditis elegans through steroid hormone and mTOR signaling. Commun Biol 2024; 7:121. [PMID: 38267699 PMCID: PMC10808130 DOI: 10.1038/s42003-024-05804-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 01/11/2024] [Indexed: 01/26/2024] Open
Abstract
Recovery from the quiescent developmental stage called dauer is an essential process in C. elegans and provides an excellent model to understand how metabolic transitions contribute to developmental plasticity. Here we show that cholesterol bound to the small secreted proteins SCL-12 or SCL-13 is sequestered in the gut lumen during the dauer state. Upon recovery from dauer, bound cholesterol undergoes endocytosis into lysosomes of intestinal cells, where SCL-12 and SCL-13 are degraded and cholesterol is released. Free cholesterol activates mTORC1 and is used for the production of dafachronic acids. This leads to promotion of protein synthesis and growth, and a metabolic switch at the transcriptional level. Thus, mobilization of sequestered cholesterol stores is the key event for transition from quiescence to growth, and cholesterol is the major signaling molecule in this process.
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Affiliation(s)
- Kathrin Schmeisser
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Damla Kaptan
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | - Andrej Shevchenko
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jonathan Rodenfels
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Physics of Life (PoL), Technical University Dresden, Dresden, Germany
| | - Sider Penkov
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Faculty of Medicine, Technical University Dresden, Dresden, Germany
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14
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Emans SW, Yerevanian A, Ahsan FM, Rotti JF, Zhou Y, Cedillo L, Soukas AA. GRD-1/PTR-11, the C. elegans hedgehog/patched-like morphogen-receptor pair, modulates developmental rate. Development 2023; 150:dev201974. [PMID: 37982457 PMCID: PMC10753586 DOI: 10.1242/dev.201974] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 11/08/2023] [Indexed: 11/21/2023]
Abstract
Both hedgehog (Hh) and target of rapamycin complex 2 (TORC2) are central, evolutionarily conserved signaling pathways that regulate development and metabolism. In C. elegans, loss of the essential TORC2 component RICTOR (rict-1) causes delayed development, shortened lifespan, reduced brood, small size and increased fat. Here, we report that knockdown of both the hedgehog-related morphogen grd-1 and its patched-related receptor ptr-11 rescues delayed development in TORC2 loss-of-function mutants, and grd-1 and ptr-11 overexpression delays wild-type development to a similar level to that in TORC2 loss-of-function animals. These findings potentially indicate an unexpected role for grd-1 and ptr-11 in slowing developmental rate downstream of a nutrient-sensing pathway. Furthermore, we implicate the chronic stress transcription factor pqm-1 as a key transcriptional effector in this slowing of whole-organism growth by grd-1 and ptr-11. We propose that TORC2, grd-1 and ptr-11 may act linearly or converge on pqm-1 to delay organismal development.
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Affiliation(s)
- Sinclair W. Emans
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Biological and Biomedical Sciences, Division of Medical Science, Harvard Medical School, Boston, MA 02115, USA
| | - Armen Yerevanian
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Fasih M. Ahsan
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Biological and Biomedical Sciences, Division of Medical Science, Harvard Medical School, Boston, MA 02115, USA
| | - Jen F. Rotti
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Yifei Zhou
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Lucydalila Cedillo
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Biological and Biomedical Sciences, Division of Medical Science, Harvard Medical School, Boston, MA 02115, USA
| | - Alexander A. Soukas
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
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15
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Wu W, Chen Z, Han J, Qian L, Wang W, Lei J, Wang H. Endocrine, genetic, and microbiome nexus of obesity and potential role of postbiotics: a narrative review. Eat Weight Disord 2023; 28:84. [PMID: 37861729 PMCID: PMC10589153 DOI: 10.1007/s40519-023-01593-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/19/2023] [Indexed: 10/21/2023] Open
Abstract
Obesity is a public health crisis, presenting a huge burden on health care and the economic system in both developed and developing countries. According to the WHO's latest report on obesity, 39% of adults of age 18 and above are obese, with an increase of 18% compared to the last few decades. Metabolic energy imbalance due to contemporary lifestyle, changes in gut microbiota, hormonal imbalance, inherent genetics, and epigenetics is a major contributory factor to this crisis. Multiple studies have shown that probiotics and their metabolites (postbiotics) supplementation have an effect on obesity-related effects in vitro, in vivo, and in human clinical investigations. Postbiotics such as the SCFAs suppress obesity by regulating metabolic hormones such as GLP-1, and PPY thus reducing feed intake and suppressing appetite. Furthermore, muramyl di-peptides, bacteriocins, and LPS have been tested against obesity and yielded promising results in both human and mice studies. These insights provide an overview of targetable pharmacological sites and explore new opportunities for the safer use of postbiotics against obesity in the future.
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Affiliation(s)
- Weiming Wu
- Department of Endocrinology, Changshu Hospital Affiliated to Nanjing University of Chinese Medicine, Changshu, 215500, Jiangsu, People's Republic of China
| | - Zhengfang Chen
- Department of Endocrinology, Changshu First People's Hospital, Changshu, 215501, Jiangsu, People's Republic of China.
| | - Jiani Han
- Department of Endocrinology, Changshu Hospital Affiliated to Nanjing University of Chinese Medicine, Changshu, 215500, Jiangsu, People's Republic of China
| | - Lingling Qian
- Department of Endocrinology, Changshu Hospital Affiliated to Nanjing University of Chinese Medicine, Changshu, 215500, Jiangsu, People's Republic of China
| | - Wanqiu Wang
- Department of Endocrinology, Changshu Hospital Affiliated to Nanjing University of Chinese Medicine, Changshu, 215500, Jiangsu, People's Republic of China
| | - Jiacai Lei
- Department of Gastroenterology, Hangzhou Ninth People's Hospital, Hangzhou, 310005, Zhejiang, People's Republic of China
| | - Huaguan Wang
- Department of Gastroenterology, Hangzhou Ninth People's Hospital, Hangzhou, 310005, Zhejiang, People's Republic of China.
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16
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Land R, Fetter R, Liang X, Tzeng CP, Taylor CA, Shen K. Endoplasmic Reticulum Exit Sites scale with somato-dendritic size in neurons. Mol Biol Cell 2023; 34:ar106. [PMID: 37556208 PMCID: PMC10559313 DOI: 10.1091/mbc.e23-03-0090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/10/2023] [Accepted: 08/02/2023] [Indexed: 08/11/2023] Open
Abstract
Nervous systems exhibit dramatic diversity in cell morphology and size. How neurons regulate their biosynthetic and secretory machinery to support such diversity is not well understood. Endoplasmic reticulum exit sites (ERESs) are essential for maintaining secretory flux, and are required for normal dendrite development, but how neurons of different size regulate secretory capacity remains unknown. In Caenorhabditis elegans, we find that the ERES number is strongly correlated with the size of a neuron's dendritic arbor. The elaborately branched sensory neuron, PVD, has especially high ERES numbers. Asymmetric cell division provides PVD with a large initial cell size critical for rapid establishment of PVD's high ERES number before neurite outgrowth, and these ERESs are maintained throughout development. Maintenance of ERES number requires the cell fate transcription factor MEC-3, C. elegans TOR (ceTOR/let-363), and nutrient availability, with mec-3 and ceTOR/let-363 mutant PVDs both displaying reductions in ERES number, soma size, and dendrite size. Notably, mec-3 mutant animals exhibit reduced expression of a ceTOR/let-363 reporter in PVD, and starvation reduces ERES number and somato-dendritic size in a manner genetically redundant with ceTOR/let-363 perturbation. Our data suggest that both asymmetric cell division and nutrient sensing pathways regulate secretory capacities to support elaborate dendritic arbors.
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Affiliation(s)
- Ruben Land
- Department of Biology, Stanford University, Stanford, CA 94305
- Neurosciences IDP, Stanford University, Stanford, CA 94305
| | - Richard Fetter
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Xing Liang
- Department of Biology, Stanford University, Stanford, CA 94305
| | - Christopher P. Tzeng
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Caitlin A. Taylor
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
| | - Kang Shen
- Department of Biology, Stanford University, Stanford, CA 94305
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305
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17
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Smith HJ, Lanjuin A, Sharma A, Prabhakar A, Nowak E, Stine PG, Sehgal R, Stojanovski K, Towbin BD, Mair WB. Neuronal mTORC1 inhibition promotes longevity without suppressing anabolic growth and reproduction in C. elegans. PLoS Genet 2023; 19:e1010938. [PMID: 37721956 PMCID: PMC10538657 DOI: 10.1371/journal.pgen.1010938] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 09/28/2023] [Accepted: 08/24/2023] [Indexed: 09/20/2023] Open
Abstract
mTORC1 (mechanistic target of rapamycin complex 1) is a metabolic sensor that promotes growth when nutrients are abundant. Ubiquitous inhibition of mTORC1 extends lifespan in multiple organisms but also disrupts several anabolic processes resulting in stunted growth, slowed development, reduced fertility, and disrupted metabolism. However, it is unclear if these pleiotropic effects of mTORC1 inhibition can be uncoupled from longevity. Here, we utilize the auxin-inducible degradation (AID) system to restrict mTORC1 inhibition to C. elegans neurons. We find that neuron-specific degradation of RAGA-1, an upstream activator of mTORC1, or LET-363, the ortholog of mammalian mTOR, is sufficient to extend lifespan in C. elegans. Unlike raga-1 loss of function genetic mutations or somatic AID of RAGA-1, neuronal AID of RAGA-1 robustly extends lifespan without impairing body size, developmental rate, brood size, or neuronal function. Moreover, while degradation of RAGA-1 in all somatic tissues alters the expression of thousands of genes, demonstrating the widespread effects of mTORC1 inhibition, degradation of RAGA-1 in neurons only results in around 200 differentially expressed genes with a specific enrichment in metabolism and stress response. Notably, our work demonstrates that targeting mTORC1 specifically in the nervous system in C. elegans uncouples longevity from growth and reproductive impairments, and that many canonical effects of low mTORC1 activity are not required to promote healthy aging. These data challenge previously held ideas about the mechanisms of mTORC1 lifespan extension and underscore the potential of promoting longevity by neuron-specific mTORC1 modulation.
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Affiliation(s)
- Hannah J. Smith
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
| | - Anne Lanjuin
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
| | - Arpit Sharma
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
| | - Aditi Prabhakar
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
| | - Ewelina Nowak
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
| | - Peter G. Stine
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
| | - Rohan Sehgal
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
| | | | | | - William B. Mair
- Dept. Molecular Metabolism, Harvard TH Chan School of Public Health, Massachusetts, United States of America
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18
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Silva-García CG. Devo-Aging: Intersections Between Development and Aging. GeroScience 2023; 45:2145-2159. [PMID: 37160658 PMCID: PMC10651630 DOI: 10.1007/s11357-023-00809-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 04/25/2023] [Indexed: 05/11/2023] Open
Abstract
There are two fundamental questions in developmental biology. How does a single fertilized cell give rise to a whole body? and how does this body later produce progeny? Synchronization of these embryonic and postembryonic developments ensures continuity of life from one generation to the next. An enormous amount of work has been done to unravel the molecular mechanisms behind these processes, but more recently, modern developmental biology has been expanded to study development in wider contexts, including regeneration, environment, disease, and even aging. However, we have just started to understand how the mechanisms that govern development also regulate aging. This review discusses examples of signaling pathways involved in development to elucidate how their regulation influences healthspan and lifespan. Therefore, a better knowledge of developmental signaling pathways stresses the possibility of using them as innovative biomarkers and targets for aging and age-related diseases.
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Affiliation(s)
- Carlos Giovanni Silva-García
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, USA.
- Center on the Biology of Aging, Brown University, Providence, RI, USA.
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19
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Marques-Ramos A, Cervantes R. Expression of mTOR in normal and pathological conditions. Mol Cancer 2023; 22:112. [PMID: 37454139 PMCID: PMC10349476 DOI: 10.1186/s12943-023-01820-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Accepted: 07/08/2023] [Indexed: 07/18/2023] Open
Abstract
The mechanistic/mammalian target of rapamycin (mTOR), a protein discovered in 1991, integrates a complex pathway with a key role in maintaining cellular homeostasis. By comprising two functionally distinct complexes, mTOR complex 1 (mTORC1) and mTORC2, it is a central cellular hub that integrates intra- and extracellular signals of energy, nutrient, and hormone availability, modulating the molecular responses to acquire a homeostatic state through the regulation of anabolic and catabolic processes. Accordingly, dysregulation of mTOR pathway has been implicated in a variety of human diseases. While major advances have been made regarding the regulators and effectors of mTOR signaling pathway, insights into the regulation of mTOR gene expression are beginning to emerge. Here, we present the current available data regarding the mTOR expression regulation at the level of transcription, translation and mRNA stability and systematize the current knowledge about the fluctuations of mTOR expression observed in several diseases, both cancerous and non-cancerous. In addition, we discuss whether mTOR expression changes can be used as a biomarker for diagnosis, disease progression, prognosis and/or response to therapeutics. We believe that our study will contribute for the implementation of new disease biomarkers based on mTOR as it gives an exhaustive perspective about the regulation of mTOR gene expression in both normal and pathological conditions.
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Affiliation(s)
- A Marques-Ramos
- H&TRC-Health & Technology Research Center, ESTeSL-Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal.
| | - R Cervantes
- H&TRC-Health & Technology Research Center, ESTeSL-Escola Superior de Tecnologia da Saúde, Instituto Politécnico de Lisboa, Lisbon, Portugal
- Public Health Research Centre, NOVA National School of Public Health, Universidade Nova de Lisboa, Lisbon, Portugal
- Comprehensive Health Research Center (CHRC), Lisbon, Portugal
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20
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Cheng X, Zhang P, Zhao H, Zheng H, Zheng K, Zhang H, Zhang H. Proteotoxic stress disrupts epithelial integrity by inducing MTOR sequestration and autophagy overactivation. Autophagy 2023; 19:241-255. [PMID: 35521960 PMCID: PMC9809964 DOI: 10.1080/15548627.2022.2071381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Macroautophagy/autophagy, an evolutionarily conserved degradation system, serves to clear intracellular components through the lysosomal pathway. Mounting evidence has revealed cytoprotective roles of autophagy; however, the intracellular causes of overactivated autophagy, which has cytotoxic effects, remain elusive. Here we show that sustained proteotoxic stress induced by loss of the RING and Kelch repeat-containing protein C53A5.6/RIKE-1 induces sequestration of LET-363/MTOR complex and overactivation of autophagy, and consequently impairs epithelial integrity in C. elegans. In C53A5.6/RIKE-1-deficient animals, blocking autophagosome formation effectively prevents excessive endosomal degradation, mitigates mislocalization of intestinal membrane components and restores intestinal lumen morphology. However, autophagy inhibition does not affect LET-363/MTOR aggregation in animals with compromised C53A5.6/RIKE-1 function. Improving proteostasis capacity by reducing DAF-2 insulin/IGF1 signaling markedly relieves the aggregation of LET-363/MTOR and alleviates autophagy overactivation, which in turn reverses derailed endosomal trafficking and rescues epithelial morphogenesis defects in C53A5.6/RIKE-1-deficient animals. Hence, our studies reveal that C53A5.6/RIKE-1-mediated proteostasis is critical for maintaining the basal level of autophagy and epithelial integrity.Abbreviations: ACT-5: actin 5; ACTB: actin beta; ALs: autolysosomes; APs: autophagosomes; AJM-1: apical junction molecule; ATG: autophagy related; C. elegans: Caenorhabditis elegans; CPL-1: cathepsin L family; DAF: abnormal dauer formation; DLG-1: Drosophila discs large homolog; ERM-1: ezrin/radixin/moesin; EPG: ectopic P granule; GFP: freen fluorescent protein; HLH-30: helix loop helix; HSP: heat shock protein; LAAT-1: lysosome associated amino acid transporter; LET: lethal; LGG-1: LC3, GABARAP and GATE-16 family; LMP-1: LAMP (lysosome-associated membrane protein) homolog; MTOR: mechanistic target of rapamycin kinase; NUC-1: abnormal nuclease; PEPT-1/OPT-2: Peptide transporter family; PGP-1: P-glycoprotein related; RAB: RAB family; RIKE-1: RING and Kelch repeat-containing protein; SLCF-1: solute carrier family; SQST-1: sequestosome related; SPTL-1: serine palmitoyl transferase family.
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Affiliation(s)
- Xiaoxiang Cheng
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau, China,National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Pei Zhang
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Hongyu Zhao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Hui Zheng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Kai Zheng
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Hong Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Hongjie Zhang
- Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau, China,MoE Frontiers Science Center for Precision Oncology, University of Macau, Taipa, Macau SAR, China,CONTACT Hongjie Zhang Centre of Reproduction, Development and Aging, Faculty of Health Sciences, University of Macau, Taipa, Macau999078, China
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21
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Feng M, Gao B, Garcia LR, Sun Q. Microbiota-derived metabolites in regulating the development and physiology of Caenorhabditis elegans. Front Microbiol 2023; 14:1035582. [PMID: 36925470 PMCID: PMC10011103 DOI: 10.3389/fmicb.2023.1035582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 02/09/2023] [Indexed: 03/08/2023] Open
Abstract
Microbiota consist of microorganisms that provide essential health benefits and contribute to the animal's physiological homeostasis. Microbiota-derived metabolites are crucial mediators in regulating host development, system homeostasis, and overall fitness. In this review, by focusing on the animal model Caenorhabditis elegans, we summarize key microbial metabolites and their molecular mechanisms that affect animal development. We also provide, from a bacterial perspective, an overview of host-microbiota interaction networks used for maintaining host physiological homeostasis. Moreover, we discuss applicable methodologies for profiling new bacterial metabolites that modulate host developmental signaling pathways. Microbiota-derived metabolites have the potential to be diagnostic biomarkers for diseases, as well as promising targets for engineering therapeutic interventions against animal developmental or health-related defects.
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Affiliation(s)
- Min Feng
- Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
| | - Baizhen Gao
- Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
| | - L Rene Garcia
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Qing Sun
- Department of Chemical Engineering, Texas A&M University, College Station, TX, United States
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22
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Li C, Zhang X. Current in Vitro and Animal Models for Understanding Foods: Human Gut-Microbiota Interactions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:12733-12745. [PMID: 36166347 DOI: 10.1021/acs.jafc.2c04238] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The food-gut microbiota interaction is an important regulator of human health. Numerous in vitro and animal models have thus been developed in order to simulate the specific food-gut microbiota and/or host-gut microbiota interactions in the human colon. This review summarizes the design principles of each model and discusses their advantages and weaknesses in terms of studying food-gut microbiota interactions. In vitro fermentation models appear to be reliable methods to investigate various aspects involved in the food-gut microbiota interactions in humans. However, many physiological perspectives lack appreciation of these models, such as peristaltic movement, biochemical conditions, and gastrointestinal anatomy. Animal models provide more physiological relevance to human trials compared to in vitro models. However, they may have gastrointestinal tract aspects that are distinct from human subjects. This review contains important information that can help the development of more advanced models to study food-gut microbiota interactions in humans.
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Affiliation(s)
- Cheng Li
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
- Joint International Research Laboratory of Agriculture Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou 225009, Jiangsu, China
| | - Xiaowei Zhang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
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23
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Li N, Hua B, Chen Q, Teng F, Ruan M, Zhu M, Zhang L, Huo Y, Liu H, Zhuang M, Shen H, Zhu H. A sphingolipid-mTORC1 nutrient-sensing pathway regulates animal development by an intestinal peroxisome relocation-based gut-brain crosstalk. Cell Rep 2022; 40:111140. [PMID: 35905721 DOI: 10.1016/j.celrep.2022.111140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 05/23/2022] [Accepted: 07/01/2022] [Indexed: 11/30/2022] Open
Abstract
The mTOR-dependent nutrient-sensing and response machinery is the central hub for animals to regulate their cellular and developmental programs. However, equivalently pivotal nutrient and metabolite signals upstream of mTOR and developmental-regulatory signals downstream of mTOR are not clear, especially at the organism level. We previously showed glucosylceramide (GlcCer) acts as a critical nutrient and metabolite signal for overall amino acid levels to promote development by activating the intestinal mTORC1 signaling pathway. Here, through a large-scale genetic screen, we find that the intestinal peroxisome is critical for antagonizing the GlcCer-mTORC1-mediated nutrient signal. Mechanistically, GlcCer deficiency, inactive mTORC1, or prolonged starvation relocates intestinal peroxisomes closer to the apical region in a kinesin- and microtubule-dependent manner. Those apical accumulated peroxisomes further release peroxisomal-β-oxidation-derived glycolipid hormones that target chemosensory neurons and downstream nuclear hormone receptor DAF-12 to arrest the animal development. Our data illustrate a sophisticated gut-brain axis that predominantly orchestrates nutrient-sensing-dependent development in animals.
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Affiliation(s)
- Na Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100000, China
| | - Beilei Hua
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qing Chen
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Fukang Teng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Meiyu Ruan
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Mengnan Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100000, China
| | - Li Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Yinbo Huo
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China; CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai 201210, China; University of Chinese Academy of Sciences, Beijing 100000, China
| | - Hongqin Liu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Min Zhuang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Huali Shen
- Institutes of Biomedical Sciences, Department of Systems Biology for Medicine and School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Huanhu Zhu
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China.
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24
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Sewell AK, Poss ZC, Ebmeier CC, Jacobsen JR, Old WM, Han M. The TORC1 phosphoproteome in C. elegans reveals roles in transcription and autophagy. iScience 2022; 25:104186. [PMID: 35479415 PMCID: PMC9036118 DOI: 10.1016/j.isci.2022.104186] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/14/2022] [Accepted: 03/29/2022] [Indexed: 11/13/2022] Open
Abstract
The protein kinase complex target of rapamycin complex 1 (TORC1) is a critical mediator of nutrient sensing that has been widely studied in cultured cells and yeast, yet our understanding of the regulatory activities of TORC1 in the context of a whole, multi-cellular organism is still very limited. Using Caenorhabditis elegans, we analyzed the DAF-15/Raptor-dependent phosphoproteome by quantitative mass spectrometry and characterized direct kinase targets by in vitro kinase assays. Here, we show new targets of TORC1 that indicate previously unknown regulation of transcription and autophagy. Our results further show that DAF-15/Raptor is differentially expressed during postembryonic development, suggesting a dynamic role for TORC1 signaling throughout the life span. This study provides a comprehensive view of the TORC1 phosphoproteome, reveals more than 100 DAF-15/Raptor-dependent phosphosites that reflect the complex function of TORC1 in a whole, multi-cellular organism, and serves as a rich resource to the field.
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Affiliation(s)
- Aileen K. Sewell
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Zachary C. Poss
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Christopher C. Ebmeier
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Jeremy R. Jacobsen
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - William M. Old
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
| | - Min Han
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO 80309-0347, USA
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25
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Hebbar S, Panzade G, Vashisht AA, Wohlschlegel JA, Veksler-Lublinsky I, Zinovyeva AY. Functional identification of microRNA-centered complexes in C. elegans. Sci Rep 2022; 12:7133. [PMID: 35504914 PMCID: PMC9065084 DOI: 10.1038/s41598-022-10771-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 04/08/2022] [Indexed: 02/02/2023] Open
Abstract
microRNAs (miRNAs) are crucial for normal development and physiology. To identify factors that might coordinate with miRNAs to regulate gene expression, we used 2'O-methylated oligonucleotides to precipitate Caenorhabditis elegans let-7, miR-58, and miR-2 miRNAs and the associated proteins. A total of 211 proteins were identified through mass-spectrometry analysis of miRNA co-precipitates, which included previously identified interactors of key miRNA pathway components. Gene ontology analysis of the identified interactors revealed an enrichment for RNA binding proteins, suggesting that we captured proteins that may be involved in mRNA lifecycle. To determine which miRNA interactors are important for miRNA activity, we used RNAi to deplete putative miRNA co-factors in animals with compromised miRNA activity and looked for alterations of the miRNA mutant phenotypes. Depletion of 25 of 39 tested genes modified the miRNA mutant phenotypes in three sensitized backgrounds. Modulators of miRNA phenotypes ranged from RNA binding proteins RBD-1 and CEY-1 to metabolic factors such as DLST-1 and ECH-5, among others. The observed functional interactions suggest widespread coordination of these proteins with miRNAs to ultimately regulate gene expression. This study provides a foundation for future investigations aimed at deciphering the molecular mechanisms of miRNA-mediated gene regulation.
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Affiliation(s)
- Shilpa Hebbar
- Division of Biology, Kansas State University, Manhattan, 66506, USA
| | - Ganesh Panzade
- Division of Biology, Kansas State University, Manhattan, 66506, USA
| | - Ajay A Vashisht
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, 90095, USA
- Genomics Institute of the Novartis Research Foundation, San Diego, 92121, USA
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, 90095, USA
| | - Isana Veksler-Lublinsky
- Department of Software and Information Systems Engineering, Ben-Gurion University of the Negev, 8410501, Beer-Sheva, Israel
| | - Anna Y Zinovyeva
- Division of Biology, Kansas State University, Manhattan, 66506, USA.
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26
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Lautens MJ, Tan JH, Serrat X, Del Borrello S, Schertzberg MR, Fraser AG. Identification of enzymes that have helminth-specific active sites and are required for Rhodoquinone-dependent metabolism as targets for new anthelmintics. PLoS Negl Trop Dis 2021; 15:e0009991. [PMID: 34843467 PMCID: PMC8659336 DOI: 10.1371/journal.pntd.0009991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 12/09/2021] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Soil transmitted helminths (STHs) are major human pathogens that infect over a billion people. Resistance to current anthelmintics is rising and new drugs are needed. Here we combine multiple approaches to find druggable targets in the anaerobic metabolic pathways STHs need to survive in their mammalian host. These require rhodoquinone (RQ), an electron carrier used by STHs and not their hosts. We identified 25 genes predicted to act in RQ-dependent metabolism including sensing hypoxia and RQ synthesis and found 9 are required. Since all 9 have mammalian orthologues, we used comparative genomics and structural modeling to identify those with active sites that differ between host and parasite. Together, we found 4 genes that are required for RQ-dependent metabolism and have different active sites. Finding these high confidence targets can open up in silico screens to identify species selective inhibitors of these enzymes as new anthelmintics.
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Affiliation(s)
- Margot J. Lautens
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - June H. Tan
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Xènia Serrat
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | | | | | - Andrew G. Fraser
- The Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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27
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Over Fifty Years of Life, Death, and Cannibalism: A Historical Recollection of Apoptosis and Autophagy. Int J Mol Sci 2021; 22:ijms222212466. [PMID: 34830349 PMCID: PMC8618802 DOI: 10.3390/ijms222212466] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 01/18/2023] Open
Abstract
Research in biomedical sciences has changed dramatically over the past fifty years. There is no doubt that the discovery of apoptosis and autophagy as two highly synchronized and regulated mechanisms in cellular homeostasis are among the most important discoveries in these decades. Along with the advancement in molecular biology, identifying the genetic players in apoptosis and autophagy has shed light on our understanding of their function in physiological and pathological conditions. In this review, we first describe the history of key discoveries in apoptosis with a molecular insight and continue with apoptosis pathways and their regulation. We touch upon the role of apoptosis in human health and its malfunction in several diseases. We discuss the path to the morphological and molecular discovery of autophagy. Moreover, we dive deep into the precise regulation of autophagy and recent findings from basic research to clinical applications of autophagy modulation in human health and illnesses and the available therapies for many diseases caused by impaired autophagy. We conclude with the exciting crosstalk between apoptosis and autophagy, from the early discoveries to recent findings.
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28
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Ke W, Reed JN, Yang C, Higgason N, Rayyan L, Wählby C, Carpenter AE, Civelek M, O’Rourke EJ. Genes in human obesity loci are causal obesity genes in C. elegans. PLoS Genet 2021; 17:e1009736. [PMID: 34492009 PMCID: PMC8462697 DOI: 10.1371/journal.pgen.1009736] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/24/2021] [Accepted: 07/23/2021] [Indexed: 12/13/2022] Open
Abstract
Obesity and its associated metabolic syndrome are a leading cause of morbidity and mortality. Given the disease's heavy burden on patients and the healthcare system, there has been increased interest in identifying pharmacological targets for the treatment and prevention of obesity. Towards this end, genome-wide association studies (GWAS) have identified hundreds of human genetic variants associated with obesity. The next challenge is to experimentally define which of these variants are causally linked to obesity, and could therefore become targets for the treatment or prevention of obesity. Here we employ high-throughput in vivo RNAi screening to test for causality 293 C. elegans orthologs of human obesity-candidate genes reported in GWAS. We RNAi screened these 293 genes in C. elegans subject to two different feeding regimens: (1) regular diet, and (2) high-fructose diet, which we developed and present here as an invertebrate model of diet-induced obesity (DIO). We report 14 genes that promote obesity and 3 genes that prevent DIO when silenced in C. elegans. Further, we show that knock-down of the 3 DIO genes not only prevents excessive fat accumulation in primary and ectopic fat depots but also improves the health and extends the lifespan of C. elegans overconsuming fructose. Importantly, the direction of the association between expression variants in these loci and obesity in mice and humans matches the phenotypic outcome of the loss-of-function of the C. elegans ortholog genes, supporting the notion that some of these genes would be causally linked to obesity across phylogeny. Therefore, in addition to defining causality for several genes so far merely correlated with obesity, this study demonstrates the value of model systems compatible with in vivo high-throughput genetic screening to causally link GWAS gene candidates to human diseases.
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Affiliation(s)
- Wenfan Ke
- Department of Biology, College of Arts and Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Jordan N. Reed
- Department of Biomedical Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia, United States of America
| | - Chenyu Yang
- Department of Biology, College of Arts and Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Noel Higgason
- Department of Biology, College of Arts and Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Leila Rayyan
- Department of Biology, College of Arts and Sciences, University of Virginia, Charlottesville, Virginia, United States of America
| | - Carolina Wählby
- Department of Information Technology and SciLifeLab, Uppsala University, Uppsala, Sweden
| | - Anne E. Carpenter
- Imaging Platform, Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Mete Civelek
- Department of Biomedical Engineering, School of Engineering and Applied Science, University of Virginia, Charlottesville, Virginia, United States of America
- Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
| | - Eyleen J. O’Rourke
- Department of Biology, College of Arts and Sciences, University of Virginia, Charlottesville, Virginia, United States of America
- Department of Cell Biology, School of Medicine, University of Virginia, Charlottesville, Virginia, United States of America
- * E-mail:
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29
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Howard AC, Mir D, Snow S, Horrocks J, Sayed H, Ma Z, Rogers AN. Anabolic Function Downstream of TOR Controls Trade-offs Between Longevity and Reproduction at the Level of Specific Tissues in C. elegans. FRONTIERS IN AGING 2021; 2:725068. [PMID: 35340273 PMCID: PMC8953723 DOI: 10.3389/fragi.2021.725068] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 08/27/2021] [Indexed: 11/20/2022]
Abstract
As the most energetically expensive cellular process, translation must be finely tuned to environmental conditions. Dietary restriction attenuates signaling through the nutrient sensing mTOR pathway, which reduces translation and redirects resources to preserve the soma. These responses are associated with increased lifespan but also anabolic impairment, phenotypes also observed when translation is genetically suppressed. Here, we restricted translation downstream of mTOR separately in major tissues in C. elegans to better understand their roles in systemic adaptation and whether consequences to anabolic impairment were separable from positive effects on lifespan. Lowering translation in neurons, hypodermis, or germline tissue led to increased lifespan under well-fed conditions and improved survival upon withdrawal of food, indicating that these are key tissues coordinating enhanced survival when protein synthesis is reduced. Surprisingly, lowering translation in body muscle during development shortened lifespan while accelerating and increasing reproduction, a reversal of phenotypic trade-offs associated with systemic translation suppression. Suppressing mTORC1 selectively in body muscle also increased reproduction while slowing motility during development. In nature, this may be indicative of reduced energy expenditure related to foraging, acting as a "GO!" signal for reproduction. Together, results indicate that low translation in different tissues helps direct distinct systemic adaptations and suggest that unknown endocrine signals mediate these responses. Furthermore, mTOR or translation inhibitory therapeutics that target specific tissues may achieve desired interventions to aging without loss of whole-body anabolism.
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Affiliation(s)
- Amber C. Howard
- Mount Desert Island Biological Laboratory, Davis Center for Regenerative Biology and Medicine, Bar Harbor, ME, United States
- Department of Natural Sciences, Middle Georgia State University, Cochran, GA, United States
| | - Dilawar Mir
- Mount Desert Island Biological Laboratory, Davis Center for Regenerative Biology and Medicine, Bar Harbor, ME, United States
| | - Santina Snow
- Mount Desert Island Biological Laboratory, Davis Center for Regenerative Biology and Medicine, Bar Harbor, ME, United States
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, United States
| | - Jordan Horrocks
- Mount Desert Island Biological Laboratory, Davis Center for Regenerative Biology and Medicine, Bar Harbor, ME, United States
| | - Hussein Sayed
- Mount Desert Island Biological Laboratory, Davis Center for Regenerative Biology and Medicine, Bar Harbor, ME, United States
| | - Zhengxin Ma
- Mount Desert Island Biological Laboratory, Davis Center for Regenerative Biology and Medicine, Bar Harbor, ME, United States
| | - Aric N. Rogers
- Mount Desert Island Biological Laboratory, Davis Center for Regenerative Biology and Medicine, Bar Harbor, ME, United States
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30
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Fry AL, Webster AK, Burnett J, Chitrakar R, Baugh LR, Hubbard EJA. DAF-18/PTEN inhibits germline zygotic gene activation during primordial germ cell quiescence. PLoS Genet 2021; 17:e1009650. [PMID: 34288923 PMCID: PMC8294487 DOI: 10.1371/journal.pgen.1009650] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 06/08/2021] [Indexed: 12/13/2022] Open
Abstract
Quiescence, an actively-maintained reversible state of cell cycle arrest, is not well understood. PTEN is one of the most frequently lost tumor suppressors in human cancers and regulates quiescence of stem cells and cancer cells. The sole PTEN ortholog in Caenorhabditis elegans is daf-18. In a C. elegans loss-of-function mutant for daf-18, primordial germ cells (PGCs) divide inappropriately in L1 larvae hatched into starvation conditions, in a TOR-dependent manner. Here, we further investigated the role of daf-18 in maintaining PGC quiescence in L1 starvation. We found that maternal or zygotic daf-18 is sufficient to maintain cell cycle quiescence, that daf-18 acts in the germ line and soma, and that daf-18 affects timing of PGC divisions in fed animals. Importantly, our results also implicate daf-18 in repression of germline zygotic gene activation, though not in germline fate specification. However, TOR is less important to germline zygotic gene expression, suggesting that in the absence of food, daf-18/PTEN prevents inappropriate germline zygotic gene activation and cell division by distinct mechanisms.
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Affiliation(s)
- Amanda L. Fry
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
| | - Amy K. Webster
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - Julia Burnett
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
| | - Rojin Chitrakar
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - L. Ryan Baugh
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - E. Jane Albert Hubbard
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
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31
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Wu CW, Storey KB. mTOR Signaling in Metabolic Stress Adaptation. Biomolecules 2021; 11:biom11050681. [PMID: 34062764 PMCID: PMC8147357 DOI: 10.3390/biom11050681] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 12/30/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a central regulator of cellular homeostasis that integrates environmental and nutrient signals to control cell growth and survival. Over the past two decades, extensive studies of mTOR have implicated the importance of this protein complex in regulating a broad range of metabolic functions, as well as its role in the progression of various human diseases. Recently, mTOR has emerged as a key signaling molecule in regulating animal entry into a hypometabolic state as a survival strategy in response to environmental stress. Here, we review current knowledge of the role that mTOR plays in contributing to natural hypometabolic states such as hibernation, estivation, hypoxia/anoxia tolerance, and dauer diapause. Studies across a diverse range of animal species reveal that mTOR exhibits unique regulatory patterns in an environmental stressor-dependent manner. We discuss how key signaling proteins within the mTOR signaling pathways are regulated in different animal models of stress, and describe how each of these regulations uniquely contribute to promoting animal survival in a hypometabolic state.
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Affiliation(s)
- Cheng-Wei Wu
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, 52 Campus Drive, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada
- Toxicology Centre, University of Saskatchewan, Saskatoon, SK S7N 5B3, Canada
- Correspondence:
| | - Kenneth B. Storey
- Institute of Biochemistry and Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON K1S 5B6, Canada;
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32
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Developmental plasticity and the response to nutrient stress in Caenorhabditis elegans. Dev Biol 2021; 475:265-276. [PMID: 33549550 DOI: 10.1016/j.ydbio.2021.01.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/24/2020] [Accepted: 01/29/2021] [Indexed: 11/23/2022]
Abstract
Developmental plasticity refers the ability of an organism to adapt to various environmental stressors, one of which is nutritional stress. Caenorhabditis elegans require various nutrients to successfully progress through all the larval stages to become a reproductive adult. If nutritional criteria are not satisfied, development can slow or completely arrest. In poor growth conditions, the animal can enter various diapause stages, depending on its developmental progress. In C. elegans, there are three well-characterized diapauses: the L1 arrest, the dauer diapause, and adult reproductive diapause, each associated with drastic changes in metabolism and germline development. At the centre of these changes is AMP-activated protein kinase (AMPK). AMPK is a metabolic regulator that maintains energy homeostasis, particularly during times of nutrient stress. Without AMPK, metabolism is disrupted during dauer, leading to the rapid consumption of lipid stores as well as misregulation of metabolic enzymes, leading to reduced survival. During the L1 arrest and dauer diapause, AMPK is responsible for ensuring germline quiescence by modifying the germline chromatin landscape to maintain germ cell integrity until conditions improve. Similar to classic hormonal signalling, small RNAs also play a critical role in regulating development and behaviour in a cell non-autonomous fashion. Thus, during the challenges associated with developmental plasticity, AMPK summons an army of signalling pathways to work collectively to preserve reproductive fitness during these periods of unprecedented uncertainty.
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33
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Alao JP, Legon L, Rallis C. Crosstalk between the mTOR and DNA Damage Response Pathways in Fission Yeast. Cells 2021; 10:cells10020305. [PMID: 33540829 PMCID: PMC7913062 DOI: 10.3390/cells10020305] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 12/14/2022] Open
Abstract
Cells have developed response systems to constantly monitor environmental changes and accordingly adjust growth, differentiation, and cellular stress programs. The evolutionarily conserved, nutrient-responsive, mechanistic target of rapamycin signaling (mTOR) pathway coordinates basic anabolic and catabolic cellular processes such as gene transcription, protein translation, autophagy, and metabolism, and is directly implicated in cellular and organismal aging as well as age-related diseases. mTOR mediates these processes in response to a broad range of inputs such as oxygen, amino acids, hormones, and energy levels, as well as stresses, including DNA damage. Here, we briefly summarize data relating to the interplays of the mTOR pathway with DNA damage response pathways in fission yeast, a favorite model in cell biology, and how these interactions shape cell decisions, growth, and cell-cycle progression. We, especially, comment on the roles of caffeine-mediated DNA-damage override. Understanding the biology of nutrient response, DNA damage and related pharmacological treatments can lead to the design of interventions towards improved cellular and organismal fitness, health, and survival.
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Affiliation(s)
- John-Patrick Alao
- ZEAB Therapeutic, University of East London, Stratford Campus, Water Lane, Stratford, London E15 4LZ, UK;
| | - Luc Legon
- School of Health, Sport and Bioscience, University of East London, Stratford Campus, Water Lane, Stratford, London E15 4LZ, UK;
| | - Charalampos Rallis
- School of Life Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK
- Correspondence:
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34
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Mata-Cabana A, Pérez-Nieto C, Olmedo M. Nutritional control of postembryonic development progression and arrest in Caenorhabditis elegans. ADVANCES IN GENETICS 2020; 107:33-87. [PMID: 33641748 DOI: 10.1016/bs.adgen.2020.11.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Developmental programs are under strict genetic control that favors robustness of the process. In order to guarantee the same outcome in different environmental situations, development is modulated by input pathways, which inform about external conditions. In the nematode Caenorhabditis elegans, the process of postembryonic development involves a series of stereotypic cell divisions, the progression of which is controlled by the nutritional status of the animal. C. elegans can arrest development at different larval stages, leading to cell arrest of the relevant divisions of the stage. This means that studying the nutritional control of development in C. elegans we can learn about the mechanisms controlling cell division in an in vivo model. In this work, we reviewed the current knowledge about the nutrient sensing pathways that control the progression or arrest of development in response to nutrient availability, with a special focus on the arrest at the L1 stage.
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Affiliation(s)
- Alejandro Mata-Cabana
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avd. Reina Mercedes, Sevilla, Spain
| | - Carmen Pérez-Nieto
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avd. Reina Mercedes, Sevilla, Spain
| | - María Olmedo
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Avd. Reina Mercedes, Sevilla, Spain.
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35
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Poupet C, Chassard C, Nivoliez A, Bornes S. Caenorhabditis elegans, a Host to Investigate the Probiotic Properties of Beneficial Microorganisms. Front Nutr 2020; 7:135. [PMID: 33425969 PMCID: PMC7786404 DOI: 10.3389/fnut.2020.00135] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/14/2020] [Indexed: 12/11/2022] Open
Abstract
Caenorhabditis elegans, a non-parasitic nematode emerges as a relevant and powerful candidate as an in vivo model for microorganisms-microorganisms and microorganisms-host interactions studies. Experiments have demonstrated the probiotic potential of bacteria since they can provide to the worm a longer lifespan, an increased resistance to pathogens and to oxidative or heat stresses. Probiotics are used to prevent or treat microbiota dysbiosis and associated pathologies but the molecular mechanisms underlying their capacities are still unknown. Beyond safety and healthy aspects of probiotics, C. elegans represents a powerful way to design large-scale studies to explore transkingdom interactions and to solve questioning about the molecular aspect of these interactions. Future challenges and opportunities would be to validate C. elegans as an in vivo tool for high-throughput screening of microorganisms for their potential probiotic use on human health and to enlarge the panels of microorganisms studied as well as the human diseases investigated.
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Affiliation(s)
- Cyril Poupet
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMRF, Aurillac, France
| | | | | | - Stéphanie Bornes
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMRF, Aurillac, France
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36
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5'-Hydroxy-6, 7, 8, 3', 4'-pentamethoxyflavone extends longevity mediated by DR-induced autophagy and oxidative stress resistance in C. elegans. GeroScience 2020; 43:759-772. [PMID: 32677024 PMCID: PMC8110683 DOI: 10.1007/s11357-020-00229-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 07/07/2020] [Indexed: 12/16/2022] Open
Abstract
5'-Hydroxy-6, 7, 8, 3', 4'-pentamethoxyflavone (5-HPF), a polymethoxyflavone compound found in dikamali gum, has been shown to exert a range of beneficial effects on health. We have previously reported that 5-HPF improves the cholinergic dysfunction and also possesses antioxidant properties in Caenorhabditis elegans. In this study, we have identified the effect of 5-HPF on the worm lifespan and its underlying molecular mechanisms. Out of the five tested pharmacological doses of 5-HPF, viz. 6.25, 12.5, 25, 50, and 100 μM, the 50 μM dose maximally extended the mean life of C. elegans by 28%. The present study revealed that 5-HPF supplementation leads to dietary restriction (DR)-like effects in the worms without altering bacterial metabolism. The analysis of mutant animals fed with 5-HPF suggested that the extended lifespan of C. elegans depends upon multiple DR-related signaling pathways, with NRF2 and FOXA being critical factors. Further investigation into the mechanistic aspects indicated that 5-HPF utilizes autophagy pathway induced by DR through the upregulation of autophagy genes bec-1 and lgg-1, evident from the increase in autophagic puncta in the seam cells of lgg-1::gfp tagged worms. This study identifies the longevity-promoting activity of 5-HPF in C. elegans regulated by oxidative stress-resistance genes and DR-induced autophagy pathway.
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37
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Qian J, Su S, Liu P. Experimental Approaches in Delineating mTOR Signaling. Genes (Basel) 2020; 11:E738. [PMID: 32630768 PMCID: PMC7397015 DOI: 10.3390/genes11070738] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/28/2020] [Accepted: 06/30/2020] [Indexed: 11/16/2022] Open
Abstract
The mTOR signaling controls essential biological functions including proliferation, growth, metabolism, autophagy, ageing, and others. Hyperactivation of mTOR signaling leads to a plethora of human disorders; thus, mTOR is an attractive drug target. The discovery of mTOR signaling started from isolation of rapamycin in 1975 and cloning of TOR genes in 1993. In the past 27 years, numerous research groups have contributed significantly to advancing our understanding of mTOR signaling and mTOR biology. Notably, a variety of experimental approaches have been employed in these studies to identify key mTOR pathway members that shape up the mTOR signaling we know today. Technique development drives mTOR research, while canonical biochemical and yeast genetics lay the foundation for mTOR studies. Here in this review, we summarize major experimental approaches used in the past in delineating mTOR signaling, including biochemical immunoprecipitation approaches, genetic approaches, immunofluorescence microscopic approaches, hypothesis-driven studies, protein sequence or motif search driven approaches, and bioinformatic approaches. We hope that revisiting these distinct types of experimental approaches will provide a blueprint for major techniques driving mTOR research. More importantly, we hope that thinking and reasonings behind these experimental designs will inspire future mTOR research as well as studies of other protein kinases beyond mTOR.
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Affiliation(s)
- Jiayi Qian
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (J.Q.); (S.S.)
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Siyuan Su
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (J.Q.); (S.S.)
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Pengda Liu
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; (J.Q.); (S.S.)
- Department of Biochemistry and Biophysics, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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38
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Shin HR, Zoncu R. The Lysosome at the Intersection of Cellular Growth and Destruction. Dev Cell 2020; 54:226-238. [PMID: 32610045 DOI: 10.1016/j.devcel.2020.06.010] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/01/2020] [Indexed: 12/27/2022]
Abstract
The lysosome is an essential catabolic organelle that consumes cellular biomass to regenerate basic building blocks that can fuel anabolic reactions. This simple view has evolved more recently to integrate novel functions of the lysosome as a key signaling center, which can steer the metabolic trajectory of cells in response to changes in nutrients, growth factors, and stress. Master protein kinases and transcription factors mediate the growth-promoting and catabolic activities of the lysosome and undergo a complex interplay that enables cellular adaptation to ever-changing metabolic conditions. Understanding how this coordination occurs will shed light on the fundamental logic of how the lysosome functions to control growth in the context of development, tissue homeostasis, and cancer.
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Affiliation(s)
- Hijai R Shin
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California Berkeley, Berkeley, CA 94720, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California Berkeley, Berkeley, CA 94720, USA.
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39
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Duong T, Rasmussen NR, Ballato E, Mote FS, Reiner DJ. The Rheb-TORC1 signaling axis functions as a developmental checkpoint. Development 2020; 147:dev.181727. [PMID: 32041790 DOI: 10.1242/dev.181727] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 01/22/2020] [Indexed: 12/12/2022]
Abstract
In many eukaryotes, the small GTPase Rheb functions as a switch to toggle activity of TOR complex 1 (TORC1) between anabolism and catabolism, thus controlling lifespan, development and autophagy. Our CRISPR-generated, fluorescently tagged endogenous Caenorhabditis elegans RHEB-1 and DAF-15/Raptor are expressed ubiquitously and localize to lysosomes. LET-363/TOR and DAF-15/Raptor are required for development beyond the third larval stage (L3). We observed that deletion of RHEB-1 similarly conferred L3 arrest. Unexpectedly, robust RNAi-mediated depletion of TORC1 components caused arrest at stages prior to L3. Accordingly, conditional depletion of endogenous DAF-15/Raptor in the soma revealed that TORC1 is required at each stage of the life cycle to progress to the next stage. Reversal of DAF-15 depletion permits arrested animals to recover to continue development. Our results are consistent with TORC1 functioning as a developmental checkpoint that governs the decision of the animal to progress through development.
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Affiliation(s)
- Tam Duong
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - Neal R Rasmussen
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - Elliot Ballato
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - F Sefakor Mote
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - David J Reiner
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
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40
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Haeussler S, Köhler F, Witting M, Premm MF, Rolland SG, Fischer C, Chauve L, Casanueva O, Conradt B. Autophagy compensates for defects in mitochondrial dynamics. PLoS Genet 2020; 16:e1008638. [PMID: 32191694 PMCID: PMC7135339 DOI: 10.1371/journal.pgen.1008638] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 04/06/2020] [Accepted: 01/28/2020] [Indexed: 12/30/2022] Open
Abstract
Compromising mitochondrial fusion or fission disrupts cellular homeostasis; however, the underlying mechanism(s) are not fully understood. The loss of C. elegans fzo-1MFN results in mitochondrial fragmentation, decreased mitochondrial membrane potential and the induction of the mitochondrial unfolded protein response (UPRmt). We performed a genome-wide RNAi screen for genes that when knocked-down suppress fzo-1MFN(lf)-induced UPRmt. Of the 299 genes identified, 143 encode negative regulators of autophagy, many of which have previously not been implicated in this cellular quality control mechanism. We present evidence that increased autophagic flux suppresses fzo-1MFN(lf)-induced UPRmt by increasing mitochondrial membrane potential rather than restoring mitochondrial morphology. Furthermore, we demonstrate that increased autophagic flux also suppresses UPRmt induction in response to a block in mitochondrial fission, but not in response to the loss of spg-7AFG3L2, which encodes a mitochondrial metalloprotease. Finally, we found that blocking mitochondrial fusion or fission leads to increased levels of certain types of triacylglycerols and that this is at least partially reverted by the induction of autophagy. We propose that the breakdown of these triacylglycerols through autophagy leads to elevated metabolic activity, thereby increasing mitochondrial membrane potential and restoring mitochondrial and cellular homeostasis.
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Affiliation(s)
- Simon Haeussler
- Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Fabian Köhler
- Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Michael Witting
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg, Germany
- Chair of Analytical Food Chemistry, Technische Universität München, Freising, Germany
| | - Madeleine F. Premm
- Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | | | - Christian Fischer
- Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
- Center for Integrated Protein Science, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
| | - Laetitia Chauve
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Olivia Casanueva
- Epigenetics Programme, The Babraham Institute, Cambridge, United Kingdom
| | - Barbara Conradt
- Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
- Center for Integrated Protein Science, Ludwig-Maximilians-University Munich, Planegg-Martinsried, Germany
- Department of Cell and Developmental Biology, Division of Biosciences, University College London, London, United Kingdom
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41
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Alexander-Floyd J, Haroon S, Ying M, Entezari AA, Jaeger C, Vermulst M, Gidalevitz T. Unexpected cell type-dependent effects of autophagy on polyglutamine aggregation revealed by natural genetic variation in C. elegans. BMC Biol 2020; 18:18. [PMID: 32093691 PMCID: PMC7038566 DOI: 10.1186/s12915-020-0750-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 02/13/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Monogenic protein aggregation diseases, in addition to cell selectivity, exhibit clinical variation in the age of onset and progression, driven in part by inter-individual genetic variation. While natural genetic variants may pinpoint plastic networks amenable to intervention, the mechanisms by which they impact individual susceptibility to proteotoxicity are still largely unknown. RESULTS We have previously shown that natural variation modifies polyglutamine (polyQ) aggregation phenotypes in C. elegans muscle cells. Here, we find that a genomic locus from C. elegans wild isolate DR1350 causes two genetically separable aggregation phenotypes, without changing the basal activity of muscle proteostasis pathways known to affect polyQ aggregation. We find that the increased aggregation phenotype was due to regulatory variants in the gene encoding a conserved autophagy protein ATG-5. The atg-5 gene itself conferred dosage-dependent enhancement of aggregation, with the DR1350-derived allele behaving as hypermorph. Surprisingly, increased aggregation in animals carrying the modifier locus was accompanied by enhanced autophagy activation in response to activating treatment. Because autophagy is expected to clear, not increase, protein aggregates, we activated autophagy in three different polyQ models and found a striking tissue-dependent effect: activation of autophagy decreased polyQ aggregation in neurons and intestine, but increased it in the muscle cells. CONCLUSIONS Our data show that cryptic natural variants in genes encoding proteostasis components, although not causing detectable phenotypes in wild-type individuals, can have profound effects on aggregation-prone proteins. Clinical applications of autophagy activators for aggregation diseases may need to consider the unexpected divergent effects of autophagy in different cell types.
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Affiliation(s)
- J Alexander-Floyd
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Present Address: Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - S Haroon
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - M Ying
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
| | - A A Entezari
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Current Address: Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, 19107, USA
| | - C Jaeger
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA
- Current Address: Department of Neuroradiology, Technical University of Munich, Munich, Germany
| | - M Vermulst
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Current Address: Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA, 90089, USA
| | - T Gidalevitz
- Biology Department, Drexel University, Philadelphia, PA, 19104, USA.
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42
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Rashid S, Pho KB, Mesbahi H, MacNeil LT. Nutrient Sensing and Response Drive Developmental Progression in Caenorhabditis elegans. Bioessays 2020; 42:e1900194. [PMID: 32003906 DOI: 10.1002/bies.201900194] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/22/2019] [Indexed: 12/18/2022]
Abstract
In response to nutrient limitation, many animals, including Caenorhabditis elegans, slow or arrest their development. This process requires mechanisms that sense essential nutrients and induce appropriate responses. When faced with nutrient limitation, C. elegans can induce both short and long-term survival strategies, including larval arrest, decreased developmental rate, and dauer formation. To select the most advantageous strategy, information from many different sensors must be integrated into signaling pathways, including target of rapamycin (TOR) and insulin, that regulate developmental progression. Here, how nutrient information is sensed and integrated into developmental decisions that determine developmental rate and progression in C. elegans is reviewed.
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Affiliation(s)
- Sabih Rashid
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, L8S 4K1, Ontario, Canada
| | - Kim B Pho
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, L8S 4K1, Ontario, Canada
| | - Hiva Mesbahi
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, L8S 4K1, Ontario, Canada
| | - Lesley T MacNeil
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, L8S 4K1, Ontario, Canada.,Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, L8S 4K1, Ontario, Canada.,Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, L8S 4K1, Ontario, Canada
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43
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Kang J, Dong Z, Hao Q, Wang J, Chen G, Liu D. The regulation of rapamycin in planarian Dugesia japonica Ichikawa & Kawakatsu, 1964 regeneration according to TOR signaling pathway. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 185:109680. [PMID: 31546204 DOI: 10.1016/j.ecoenv.2019.109680] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/11/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
The freshwater planarian mostly lives in the upper reaches of springs and rivers. Generally, it is realized as a suitable warning indicator of environmental toxicants. The freshwater planarian Dugesia japonica has a powerful regenerative capability and can regenerate a new individual including a complete central nervous system in one week. Rapamycin is an inhibitor of mammalian TORC1 (target of rapamycin complex-1) and used in the treatment of some diseases like cancer, cardiovascular and neurological diseases. However, the roles of rapamycin in the regulation of planarian regeneration remain to be elucidated. In present study, freshwater planarians D. japonica were firstly treated with 1 μM rapamycin for 18 h exposures and the expression patterns of Djtor was analyzed by the whole-mount in situ hybridization (WISH). Our results indicated rapamycin could strongly inhibit Djtor expression in planarian D. japonica and cause asymmetric blastemas and neuronal defects in planarians. Furthermore, knockdown of Djtor gene in planarians using RNA interference resulted in the suppression of downstream autophagy genes. These findings suggested that rapamycin might regulate freshwater planarian regeneration via Djtor signaling pathway.
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Affiliation(s)
- Jing Kang
- College of Life Science, Henan Normal University, Xinxiang, China; College of Life Science, Xingxiang Medical University, Xinxiang, China.
| | - Zimei Dong
- College of Life Science, Henan Normal University, Xinxiang, China
| | - Qin Hao
- College of Life Science, Henan Normal University, Xinxiang, China
| | - Jing Wang
- College of Life Science, Henan Normal University, Xinxiang, China
| | - Guangwen Chen
- College of Life Science, Henan Normal University, Xinxiang, China.
| | - Dezeng Liu
- College of Life Science, Henan Normal University, Xinxiang, China
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44
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Blackwell TK, Sewell AK, Wu Z, Han M. TOR Signaling in Caenorhabditis elegans Development, Metabolism, and Aging. Genetics 2019; 213:329-360. [PMID: 31594908 PMCID: PMC6781902 DOI: 10.1534/genetics.119.302504] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 07/18/2019] [Indexed: 12/30/2022] Open
Abstract
The Target of Rapamycin (TOR or mTOR) is a serine/threonine kinase that regulates growth, development, and behaviors by modulating protein synthesis, autophagy, and multiple other cellular processes in response to changes in nutrients and other cues. Over recent years, TOR has been studied intensively in mammalian cell culture and genetic systems because of its importance in growth, metabolism, cancer, and aging. Through its advantages for unbiased, and high-throughput, genetic and in vivo studies, Caenorhabditis elegans has made major contributions to our understanding of TOR biology. Genetic analyses in the worm have revealed unexpected aspects of TOR functions and regulation, and have the potential to further expand our understanding of how growth and metabolic regulation influence development. In the aging field, C. elegans has played a leading role in revealing the promise of TOR inhibition as a strategy for extending life span, and identifying mechanisms that function upstream and downstream of TOR to influence aging. Here, we review the state of the TOR field in C. elegans, and focus on what we have learned about its functions in development, metabolism, and aging. We discuss knowledge gaps, including the potential pitfalls in translating findings back and forth across organisms, but also describe how TOR is important for C. elegans biology, and how C. elegans work has developed paradigms of great importance for the broader TOR field.
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Affiliation(s)
- T Keith Blackwell
- Research Division, Joslin Diabetes Center, Department of Genetics, Harvard Medical School, Harvard Stem Cell Institute, Boston, Massachusetts
| | - Aileen K Sewell
- Department of MCDB, University of Colorado at Boulder, and
- Howard Hughes Medical Institute, Boulder, Colorado
| | - Ziyun Wu
- Research Division, Joslin Diabetes Center, Department of Genetics, Harvard Medical School, Harvard Stem Cell Institute, Boston, Massachusetts
| | - Min Han
- Department of MCDB, University of Colorado at Boulder, and
- Howard Hughes Medical Institute, Boulder, Colorado
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45
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Zhang Y, Lanjuin A, Chowdhury SR, Mistry M, Silva-García CG, Weir HJ, Lee CL, Escoubas CC, Tabakovic E, Mair WB. Neuronal TORC1 modulates longevity via AMPK and cell nonautonomous regulation of mitochondrial dynamics in C. elegans. eLife 2019; 8:49158. [PMID: 31411562 PMCID: PMC6713509 DOI: 10.7554/elife.49158] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/11/2019] [Indexed: 11/13/2022] Open
Abstract
Target of rapamycin complex 1 (TORC1) and AMP-activated protein kinase (AMPK) antagonistically modulate metabolism and aging. However, how they coordinate to determine longevity and if they act via separable mechanisms is unclear. Here, we show that neuronal AMPK is essential for lifespan extension from TORC1 inhibition, and that TORC1 suppression increases lifespan cell non autonomously via distinct mechanisms from global AMPK activation. Lifespan extension by null mutations in genes encoding raga-1 (RagA) or rsks-1 (S6K) is fully suppressed by neuronal-specific rescues. Loss of RAGA-1 increases lifespan via maintaining mitochondrial fusion. Neuronal RAGA-1 abrogation of raga-1 mutant longevity requires UNC-64/syntaxin, and promotes mitochondrial fission cell nonautonomously. Finally, deleting the mitochondrial fission factor DRP-1 renders the animal refractory to the pro-aging effects of neuronal RAGA-1. Our results highlight a new role for neuronal TORC1 in cell nonautonomous regulation of longevity, and suggest TORC1 in the central nervous system might be targeted to promote healthy aging.
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Affiliation(s)
- Yue Zhang
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - Anne Lanjuin
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - Suvagata Roy Chowdhury
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - Meeta Mistry
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - Carlos G Silva-García
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - Heather J Weir
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - Chia-Lin Lee
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States.,Department of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Caroline C Escoubas
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States.,Faculty of Medicine, Université Côte d'Azur, CNRS, INSERM, IRCAN, Nice, France
| | - Emina Tabakovic
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - William B Mair
- Department of Genetics and Complex Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
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46
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Piechulek A, Berwanger LC, von Mikecz A. Silica nanoparticles disrupt OPT-2/PEP-2-dependent trafficking of nutrient peptides in the intestinal epithelium. Nanotoxicology 2019; 13:1133-1148. [DOI: 10.1080/17435390.2019.1643048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Annette Piechulek
- IUF – Leibniz Research Institute for Environmental Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Lutz C. Berwanger
- IUF – Leibniz Research Institute for Environmental Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
| | - Anna von Mikecz
- IUF – Leibniz Research Institute for Environmental Medicine, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany
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47
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Gomez SR, Morgans S, Kristan DM. Rapamycin exposure to host and to adult worms affects life history traits of Heligmosomoides bakeri. Exp Parasitol 2019; 204:107720. [PMID: 31279929 DOI: 10.1016/j.exppara.2019.107720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/26/2019] [Accepted: 07/03/2019] [Indexed: 01/24/2023]
Abstract
Parasite life history can be affected by conditions of the host and of the external environment. Rapamycin, a known immunosuppressant of mammals, was fed to laboratory mice that were then infected with the Trichostrongylid nematode Heligmosomoides bakeri to determine if host rapamycin exposure would affect parasite survival, growth, and reproduction. In addition, adult worms from control fed mice were directly exposed to rapamycin to assess if rapamycin would affect worm viability and ex vivo reproduction. We found that host ingestion of rapamycin did not affect H. bakeri survival or growth for male or female worms, but female worms had increased reproduction both in vivo and when removed from the host and cultured ex vivo. After direct rapamycin exposure, motility of female worms was greater at low levels of rapamycin compared to high levels of rapamycin or high levels of DMSO (the vehicle used to solubilize rapamycin) in control media, but was similar to females in low levels of DMSO in control media. Male motility was not affected by the presence of rapamycin or DMSO in the media. Ex vivo egg deposition was higher when exposed to rapamycin than when cultured in control media that contained DMSO, regardless of DMSO dose. Overall, we conclude that host ingestion of rapamycin or direct exposure to rapamycin was generally favorable or neutral for parasite life history traits.
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Affiliation(s)
- Sarah R Gomez
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA
| | - Scott Morgans
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA
| | - Deborah M Kristan
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA.
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Rollins JA, Shaffer D, Snow SS, Kapahi P, Rogers AN. Dietary restriction induces posttranscriptional regulation of longevity genes. Life Sci Alliance 2019; 2:2/4/e201800281. [PMID: 31253655 PMCID: PMC6600014 DOI: 10.26508/lsa.201800281] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 06/19/2019] [Accepted: 06/20/2019] [Indexed: 12/12/2022] Open
Abstract
Dietary restriction (DR) increases life span through adaptive changes in gene expression. To understand more about these changes, we analyzed the transcriptome and translatome of Caenorhabditis elegans subjected to DR. Transcription of muscle regulatory and structural genes increased, whereas increased expression of amino acid metabolism and neuropeptide signaling genes was controlled at the level of translation. Evaluation of posttranscriptional regulation identified putative roles for RNA-binding proteins, RNA editing, miRNA, alternative splicing, and nonsense-mediated decay in response to nutrient limitation. Using RNA interference, we discovered several differentially expressed genes that regulate life span. We also found a compensatory role for translational regulation, which offsets dampened expression of a large subset of transcriptionally down-regulated genes. Furthermore, 3' UTR editing and intron retention increase under DR and correlate with diminished translation, whereas trans-spliced genes are refractory to reduced translation efficiency compared with messages with the native 5' UTR. Finally, we find that smg-6 and smg-7, which are genes governing selection and turnover of nonsense-mediated decay targets, are required for increased life span under DR.
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Affiliation(s)
- Jarod A Rollins
- Mount Desert Island Biological Laboratory, Salisbury Cove, ME, USA
| | - Dan Shaffer
- Mount Desert Island Biological Laboratory, Salisbury Cove, ME, USA
| | - Santina S Snow
- Mount Desert Island Biological Laboratory, Salisbury Cove, ME, USA
| | - Pankaj Kapahi
- Buck Institute for Research on Aging, Novato, CA, USA
| | - Aric N Rogers
- Mount Desert Island Biological Laboratory, Salisbury Cove, ME, USA
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ROS-mediated relationships between metabolism and DAF-16 subcellular localization in Caenorhabditis elegans revealed by a novel fluorometric method. Cell Signal 2019; 62:109330. [PMID: 31152844 DOI: 10.1016/j.cellsig.2019.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/27/2019] [Accepted: 05/28/2019] [Indexed: 11/21/2022]
Abstract
Signalling pathways provide a fine-tuned control network for catabolic and anabolic cellular processes under changing environmental conditions (e.g. changes in oxygen partial pressure, Po2). These pathways frequently activate or deactivate transcription factors (TFs) in the cytoplasm, with the subsequent nuclear translocation of activated TFs constituting a prerequisite for gene control and expression. This study introduces a newly developed fluorometric method for the quantification of relationships between environmental factors and the subcellular localization of reporter-coupled TFs in Caenorhabditis elegans (and possibly other transparent organisms). We applied this method to determine and analyse the relationship between Po2 and the subcellular localization of the GFP-coupled transcription factor DAF-16 (FoxO) of the DAF-2 (insulin/IGF-1) signalling pathway via the DAF-16::GFP fluorescence intensity of whole worms (Po2 characteristic). The Po2 characteristic resembled the Po2-specific metabolic rate of C. elegans, with a critical Po2 (Pco2) of 3.6 kPa separating two Po2 ranges, where either anaerobic metabolism and DAF-16::GFP nuclear occupancy strongly increased (i.e. decreasing DAF-16::GFP fluorescence intensity) (Po2 < Pco2) or aerobic metabolism and DAF-16::GFP cytoplasmic localization prevailed (Po2 > Pco2). These results and other data, which included the Po2-specific mitochondrial oxidation-reduction state of whole worms (as determined using the endogenous NADH fluorescence) and the effects of higher levels of reactive oxygen species (ROS) or RNAi-mediated knockdowns of catabolic or anabolic control genes (aak-2 or let-363) on the Po2 characteristic, suggest that ROS play a decisive role for DAF-16 nuclear translocation due to tissue hypoxia or higher anabolic activity induced by aak-2(RNAi). As DAF-16 and its target genes are of central importance for the cellular stress resistance, ROS-mediated relationships between metabolism and DAF-16 subcellular (i.e. nuclear) localization provide protection of the cell machinery against elevated ROS formation under challenging metabolic conditions.
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Murphy JT, Liu H, Ma X, Shaver A, Egan BM, Oh C, Boyko A, Mazer T, Ang S, Khopkar R, Javaheri A, Kumar S, Jiang X, Ory D, Mani K, Matkovich SJ, Kornfeld K, Diwan A. Simple nutrients bypass the requirement for HLH-30 in coupling lysosomal nutrient sensing to survival. PLoS Biol 2019; 17:e3000245. [PMID: 31086360 PMCID: PMC6516633 DOI: 10.1371/journal.pbio.3000245] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Accepted: 04/10/2019] [Indexed: 12/11/2022] Open
Abstract
Lysosomes are ubiquitous acidified organelles that degrade intracellular and extracellular material trafficked via multiple pathways. Lysosomes also sense cellular nutrient levels to regulate target of rapamycin (TOR) kinase, a signaling enzyme that drives growth and suppresses activity of the MiT/TFE family of transcription factors that control biogenesis of lysosomes. In this study, we subjected worms lacking basic helix–loop–helix transcription factor 30 (hlh-30), the Caenorhabditis elegans MiT/TFE ortholog, to starvation followed by refeeding to understand how this pathway regulates survival with variable nutrient supply. Loss of HLH-30 markedly impaired survival in starved larval worms and recovery upon refeeding bacteria. Remarkably, provision of simple nutrients in a completely defined medium (C. elegans maintenance medium [CeMM]), specifically glucose and linoleic acid, restored lysosomal acidification, TOR activation, and survival with refeeding despite the absence of HLH-30. Worms deficient in lysosomal lipase 2 (lipl-2), a lysosomal enzyme that is transcriptionally up-regulated in starvation in an HLH-30–dependent manner, also demonstrated increased mortality with starvation–refeeding that was partially rescued with glucose, suggesting a critical role for LIPL-2 in lipid metabolism under starvation. CeMM induced transcription of vacuolar proton pump subunits in hlh-30 mutant worms, and knockdown of vacuolar H+-ATPase 12 (vha-12) and its upstream regulator, nuclear hormone receptor 31 (nhr-31), abolished the rescue with CeMM. Loss of Ras-related GTP binding protein C homolog 1 RAGC-1, the ortholog for mammalian RagC/D GTPases, conferred starvation–refeeding lethality, and RAGC-1 overexpression was sufficient to rescue starved hlh-30 mutant worms, demonstrating a critical need for TOR activation with refeeding. These results show that HLH-30 activation is critical for sustaining survival during starvation–refeeding stress via regulating TOR. Glucose and linoleic acid bypass the requirement for HLH-30 in coupling lysosome nutrient sensing to survival. Lysosomes play a central role in coupling the nutrient state of the cell to growth and survival decisions. This study uncovers a critical role for HLH-30, the nematode ortholog of the mammalian MiT/TFE family of master regulators of lysosome biogenesis, in survival under starvation and refeeding conditions. Refeeding simple nutrients bypasses the requirement for HLH-30 to permit survival.
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Affiliation(s)
- John T. Murphy
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Haiyan Liu
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
| | - Xiucui Ma
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
| | - Alex Shaver
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Brian M. Egan
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Clara Oh
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Alexander Boyko
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Travis Mazer
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Samuel Ang
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Rohan Khopkar
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Ali Javaheri
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Sandeep Kumar
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Xuntian Jiang
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Daniel Ory
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kartik Mani
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
| | - Scot J. Matkovich
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Kerry Kornfeld
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Abhinav Diwan
- Center for Cardiovascular Research and Division of Cardiology, Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America
- John Cochran VA Medical Center, St. Louis, Missouri, United States of America
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- * E-mail:
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