1
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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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2
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Cedillo L, Ahsan FM, Li S, Stuhr NL, Zhou Y, Zhang Y, Adedoja A, Murphy LM, Yerevanian A, Emans S, Dao K, Li Z, Peterson ND, Watrous J, Jain M, Das S, Pukkila-Worley R, Curran SP, Soukas AA. Ether lipid biosynthesis promotes lifespan extension and enables diverse pro-longevity paradigms in Caenorhabditis elegans. eLife 2023; 12:e82210. [PMID: 37606250 PMCID: PMC10444025 DOI: 10.7554/elife.82210] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 07/13/2023] [Indexed: 08/23/2023] Open
Abstract
Biguanides, including the world's most prescribed drug for type 2 diabetes, metformin, not only lower blood sugar, but also promote longevity in preclinical models. Epidemiologic studies in humans parallel these findings, indicating favorable effects of metformin on longevity and on reducing the incidence and morbidity associated with aging-related diseases. Despite this promise, the full spectrum of molecular effectors responsible for these health benefits remains elusive. Through unbiased screening in Caenorhabditis elegans, we uncovered a role for genes necessary for ether lipid biosynthesis in the favorable effects of biguanides. We demonstrate that biguanides prompt lifespan extension by stimulating ether lipid biogenesis. Loss of the ether lipid biosynthetic machinery also mitigates lifespan extension attributable to dietary restriction, target of rapamycin (TOR) inhibition, and mitochondrial electron transport chain inhibition. A possible mechanistic explanation for this finding is that ether lipids are required for activation of longevity-promoting, metabolic stress defenses downstream of the conserved transcription factor skn-1/Nrf. In alignment with these findings, overexpression of a single, key, ether lipid biosynthetic enzyme, fard-1/FAR1, is sufficient to promote lifespan extension. These findings illuminate the ether lipid biosynthetic machinery as a novel therapeutic target to promote healthy aging.
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Affiliation(s)
- Lucydalila Cedillo
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
- Program in Biological and Biomedical Sciences, Division of Medical Sciences, Harvard Medical SchoolBostonUnited States
| | - Fasih M Ahsan
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
- Program in Biological and Biomedical Sciences, Division of Medical Sciences, Harvard Medical SchoolBostonUnited States
| | - Sainan Li
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
| | - Nicole L Stuhr
- Leonard Davis School of Gerontology, University of Southern CaliforniaLos AngelesUnited States
| | - Yifei Zhou
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
| | - Yuyao Zhang
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
| | - Adebanjo Adedoja
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
- Program in Biological and Biomedical Sciences, Division of Medical Sciences, Harvard Medical SchoolBostonUnited States
| | - Luke M Murphy
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
- Program in Biological and Biomedical Sciences, Division of Medical Sciences, Harvard Medical SchoolBostonUnited States
| | - Armen Yerevanian
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
| | - Sinclair Emans
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
| | - Khoi Dao
- Department of Medicine and Pharmacology, University of California San DiegoSan DiegoUnited States
| | - Zhaozhi Li
- Biomedical Informatics Core, Massachusetts General Hospital and Harvard Medical SchooCambridgeUnited States
| | - Nicholas D Peterson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Jeramie Watrous
- Department of Medicine and Pharmacology, University of California San DiegoSan DiegoUnited States
| | - Mohit Jain
- Department of Medicine and Pharmacology, University of California San DiegoSan DiegoUnited States
| | - Sudeshna Das
- Biomedical Informatics Core, Massachusetts General Hospital and Harvard Medical SchooCambridgeUnited States
| | - Read Pukkila-Worley
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical SchoolWorcesterUnited States
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern CaliforniaLos AngelesUnited States
| | - Alexander A Soukas
- Center for Genomic Medicine and Diabetes Unit, Endocrine Division, Department of Medicine, Massachusetts General Hospital and Harvard Medical SchoolBostonUnited States
- Broad Institute of Harvard and MITCambridgeUnited States
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3
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Application of Caenorhabditis elegans in Lipid Metabolism Research. Int J Mol Sci 2023; 24:ijms24021173. [PMID: 36674689 PMCID: PMC9860639 DOI: 10.3390/ijms24021173] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/01/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
Over the last decade, the development and prevalence of obesity have posed a serious public health risk, which has prompted studies on the regulation of adiposity. With the ease of genetic manipulation, the diversity of the methods for characterizing body fat levels, and the observability of feeding behavior, Caenorhabditis elegans (C. elegans) is considered an excellent model for exploring energy homeostasis and the regulation of the cellular fat storage. In addition, the homology with mammals in the genes related to the lipid metabolism allows many aspects of lipid modulation by the regulators of the central nervous system to be conserved in this ideal model organism. In recent years, as the complex network of genes that maintain an energy balance has been gradually expanded and refined, the regulatory mechanisms of lipid storage have become clearer. Furthermore, the development of methods and devices to assess the lipid levels has become a powerful tool for studies in lipid droplet biology and the regulation of the nematode lipid metabolism. Herein, based on the rapid progress of C. elegans lipid metabolism-related studies, this review outlined the lipid metabolic processes, the major signaling pathways of fat storage regulation, and the primary experimental methods to assess the lipid content in nematodes. Therefore, this model system holds great promise for facilitating the understanding, management, and therapies of human obesity and other metabolism-related diseases.
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4
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Qin S, Wang Y, Li L, Liu J, Xiao C, Duan D, Hao W, Qin C, Chen J, Yao L, Zhang R, You J, Zheng JS, Shen E, Wu L. Early-life vitamin B12 orchestrates lipid peroxidation to ensure reproductive success via SBP-1/SREBP1 in Caenorhabditis elegans. Cell Rep 2022; 40:111381. [PMID: 36130518 DOI: 10.1016/j.celrep.2022.111381] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 07/05/2022] [Accepted: 08/27/2022] [Indexed: 11/03/2022] Open
Abstract
Vitamin B12 (B12) deficiency is a critical problem worldwide. Such deficiency in infants has long been known to increase the propensity to develop obesity and diabetes later in life through unclear mechanisms. Here, we establish a Caenorhabditis elegans model to study how early-life B12 impacts adult health. We find that early-life B12 deficiency causes increased lipogenesis and lipid peroxidation in adult worms, which in turn induces germline defects through ferroptosis. Mechanistically, we show the central role of the methionine cycle-SBP-1/SREBP1-lipogenesis axis in programming adult traits by early-life B12. Moreover, SBP-1/SREBP1 participates in a crucial feedback loop with NHR-114/HNF4 to maintain cellular B12 homeostasis. Inhibition of SBP-1/SREBP1-lipogenesis signaling and ferroptosis later in life can reverse disorders in adulthood when B12 cannot. Overall, this study provides mechanistic insights into the life-course effects of early-life B12 on the programming of adult health and identifies potential targets for future interventions for adiposity and infertility.
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Affiliation(s)
- Shenlu Qin
- Fudan University, Shanghai, China; Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Yihan Wang
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Lili Li
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Junli Liu
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Congmei Xiao
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Duo Duan
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Wanyu Hao
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Chunxia Qin
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Jie Chen
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Luxia Yao
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Runshuai Zhang
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Jia You
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Ju-Sheng Zheng
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Enzhi Shen
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
| | - Lianfeng Wu
- Key Laboratory of Growth Regulation and Translational Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, China; Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, Zhejiang, China; Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China.
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5
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Adams S, Pathak P, Kittelmann M, Jones ARC, Mallon EB, Pires-daSilva A. Sexual morph specialisation in a trioecious nematode balances opposing selective forces. Sci Rep 2022; 12:6402. [PMID: 35431314 PMCID: PMC9013718 DOI: 10.1038/s41598-022-09900-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 03/10/2022] [Indexed: 11/27/2022] Open
Abstract
The coexistence of different mating strategies, whereby a species can reproduce both by selfing and outcrossing, is an evolutionary enigma. Theory predicts two predominant stable mating states: outcrossing with strong inbreeding depression or selfing with weak inbreeding depression. As these two mating strategies are subject to opposing selective forces, mixed breeding systems are thought to be a rare transitory state yet can persist even after multiple speciation events. We hypothesise that if each mating strategy plays a distinctive role during some part of the species life history, opposing selective pressures could be balanced, permitting the stable co-existence of selfing and outcrossing sexual morphs. In this scenario, we would expect each morph to be specialised in their respective roles. Here we show, using behavioural, physiological and gene expression studies, that the selfing (hermaphrodite) and outcrossing (female) sexual morphs of the trioecious nematode Auanema freiburgensis have distinct adaptations optimised for their different roles during the life cycle. A. freiburgensis hermaphrodites are known to be produced under stressful conditions and are specialised for dispersal to new habitat patches. Here we show that they exhibit metabolic and intestinal changes enabling them to meet the cost of dispersal and reproduction. In contrast, A. freiburgensis females are produced in favourable conditions and facilitate rapid population growth. We found that females compensate for the lack of reproductive assurance by reallocating resources from intestinal development to mate-finding behaviour. The specialisation of each mating system for its role in the life cycle could balance opposing selective forces allowing the stable maintenance of both mating systems in A. freiburgensis.
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Affiliation(s)
- Sally Adams
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK.
| | - Prachi Pathak
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Headington Campus, Oxford, OX3 0BP, UK
| | - Alun R C Jones
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
| | - Eamonn B Mallon
- Department of Genetics and Genome Biology, University of Leicester, University Road, Leicester, LE1 7RH, UK
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6
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Goncalves J, Wan Y, Garcia LR. Stearoyl-CoA desaturases sustain cholinergic excitation and copulatory robustness in metabolically aging C. elegansmales. iScience 2022; 25:104082. [PMID: 35372802 PMCID: PMC8968053 DOI: 10.1016/j.isci.2022.104082] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 02/02/2022] [Accepted: 03/14/2022] [Indexed: 01/22/2023] Open
Abstract
Regulated metabolism is required for behaviors as adults age. To understand how lipid usage affects motor coordination, we studied male Caenorhabditis elegans copulation as a model of energy-intensive behavior. Copulation performance drops after 48 h of adulthood. We found that 12–24 h before behavioral decline, males prioritize exploring and copulation behavior over feeding, suggesting that catabolizing stored metabolites, such as lipids, occurs during this period. Because fat-6/7-encoded stearoyl-CoA desaturases are essential for converting the ingested fatty acids to lipid storage, we examined the copulation behavior and neural calcium transients of fat-6(lf); fat-7(lf) mutants. In wild-type males, intestinal and epithelial fat-6/7 expression increases during the first 48 h of adulthood. The fat-6(lf); fat-7(lf) behavioral and metabolic defects indicate that in aging wild-type males, the increased expression of stearoyl-CoA desaturases in the epidermis may indirectly modulate the levels of EAG-family K+ channels in the reproductive cholinergic neurons and muscles. Tissue distribution of fat-6-encoded stearoyl-CoA desaturase changes in adulthood Markov modeling shows reduced feeding linked with more exploring in day 2 males fat-6(lf); fat-7(lf) disrupted behavior can be rescued by epidermal FAT-6 fat-6(lf); fat-7(lf) alters neural and muscular ERG and EAG K+ channel expression
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Affiliation(s)
- Jimmy Goncalves
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - Yufeng Wan
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
| | - L René Garcia
- Department of Biology, Texas A&M University, College Station, TX 77843, USA
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7
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Stuhr NL, Nhan JD, Hammerquist AM, Van Camp B, Reoyo D, Curran SP. Rapid Lipid Quantification in Caenorhabditis elegans by Oil Red O and Nile Red Staining. Bio Protoc 2022; 12:e4340. [PMID: 35592599 PMCID: PMC8918222 DOI: 10.21769/bioprotoc.4340] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 09/29/2021] [Accepted: 01/12/2022] [Indexed: 01/21/2023] Open
Abstract
The ability to stain lipid stores in vivo allows for the facile assessment of metabolic status in individuals of a population following genetic and environmental manipulation or pharmacological treatment. In the animal model Caenorhabditis elegans, lipids are stored in and mobilized from intracellular lipid droplets in the intestinal and hypodermal tissues. The abundance, size, and distribution of these lipids can be readily assessed by two staining methods for neutral lipids: Oil Red O (ORO) and Nile Red (NR). ORO and NR can be used to quantitatively measure lipid droplet abundance, while ORO can also define tissue distribution and lipid droplet size. C. elegans are a useful animal model in studying pathways relating to aging, fat storage, and metabolism, as their transparent nature allows for easy microscopic assessment of lipid droplets. This is done by fixation and permeabilization, staining with NR or ORO, image capture on a microscope, and computational identification and quantification of lipid droplets in individuals within a cohort. To ensure reproducibility in lipid measurements, we provide a detailed protocol to measure intracellular lipid dynamics in C. elegans. Graphic abstract: Flow chart depicting the preparation of C. elegans for fat staining protocols.
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Affiliation(s)
- Nicole L Stuhr
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, United States.,Department of Molecular and Computational Biology, Dornsife College of Letters, Arts and Science, University of Southern California, Los Angeles, United States
| | - James D Nhan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, United States.,Department of Molecular and Computational Biology, Dornsife College of Letters, Arts and Science, University of Southern California, Los Angeles, United States
| | - Amy M Hammerquist
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, United States.,Department of Molecular and Computational Biology, Dornsife College of Letters, Arts and Science, University of Southern California, Los Angeles, United States
| | - Bennett Van Camp
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, United States
| | - David Reoyo
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, United States
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, United States.,Department of Molecular and Computational Biology, Dornsife College of Letters, Arts and Science, University of Southern California, Los Angeles, United States.,Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, United States
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8
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Gulyas L, Powell JR. Cold shock induces a terminal investment reproductive response in C. elegans. Sci Rep 2022; 12:1338. [PMID: 35079060 PMCID: PMC8789813 DOI: 10.1038/s41598-022-05340-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 12/08/2021] [Indexed: 12/04/2022] Open
Abstract
Challenges from environmental stressors have a profound impact on many life-history traits of an organism, including reproductive strategy. Examples across multiple taxa have demonstrated that maternal reproductive investment resulting from stress can improve offspring survival; a form of matricidal provisioning when death appears imminent is known as terminal investment. Here we report a reproductive response in the nematode Caenorhabditis elegans upon exposure to acute cold shock at 2 °C, whereby vitellogenic lipid movement from the soma to the germline appears to be massively upregulated at the expense of parental survival. This response is dependent on functional TAX-2; TAX-4 cGMP-gated channels that are part of canonical thermosensory mechanisms in worms and can be prevented in the presence of activated SKN-1/Nrf2, the master stress regulator. Increased maternal provisioning promotes improved embryonic cold shock survival, which is notably suppressed in animals with impaired vitellogenesis. These findings suggest that cold shock in C. elegans triggers terminal investment to promote progeny fitness at the expense of parental survival and may serve as a tractable model for future studies of stress-induced progeny plasticity.
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Affiliation(s)
- Leah Gulyas
- Department of Biology, Gettysburg College, Gettysburg, PA, 17325, USA.,Plant and Microbial Biology Department, University of California Berkeley, Berkeley, CA, 94702, USA
| | - Jennifer R Powell
- Department of Biology, Gettysburg College, Gettysburg, PA, 17325, USA.
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9
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Nielsen T, Crawford N, Martell M, Khalil B, Imtiaz F, Newell-Caito JL, Caito S. MicroRNA Expression Influences Methylmercury-Induced Lipid Accumulation and Mitochondrial Toxicity in Caenorhabditis elegans. Chem Res Toxicol 2021; 35:77-88. [PMID: 34905692 DOI: 10.1021/acs.chemrestox.1c00306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Metabolic effects of methylmercury (MeHg) are gaining wider attention. We have previously shown that MeHg causes lipid dysregulation in Caenorhabditis elegans (C. elegans), leading to altered gene expression, increased triglyceride levels and lipid storage, and altered feeding behaviors. Transcriptional regulators, such as transcription factors and microRNAs (miRNAs), have been shown to regulate lipid storage, serum triglycerides, and adipogenic gene expression in human and rodent models of metabolic diseases. As we recently investigated adipogenic transcription factors induced by MeHg, we were, therefore, interested in whether MeHg may also regulate miRNA sequences to cause metabolic dysfunction. Lipid dysregulation, as measured by triglyceride levels, lipid storage sites, and feeding behaviors, was assessed in wild-type (N2) worms and in transgenic worms that either were sensitive to miRNA expression or were unable to process miRNAs. Worms that were sensitive to the miRNA expression were protected from MeHg-induced lipid dysregulation. In contrast, the mutant worms that were unable to process miRNAs had exacerbated MeHg-induced lipid dysregulation. Concurrent with differential lipid homeostasis, miRNA-expression mutants had altered MeHg-induced mitochondrial toxicity as compared to N2, with the miRNA-sensitive mutants showing mitochondrial protection and the miRNA-processing mutants showing increased mitotoxicity. Taken together, our data demonstrate that the expression of miRNAs is an important determinant in MeHg toxicity and MeHg-induced metabolic dysfunction in C. elegans.
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Affiliation(s)
- Tyson Nielsen
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, Husson University, Bangor, Maine 04401, United States
| | - Nicole Crawford
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, Husson University, Bangor, Maine 04401, United States
| | - Megan Martell
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, Husson University, Bangor, Maine 04401, United States
| | - Belal Khalil
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, Husson University, Bangor, Maine 04401, United States
| | - Farooq Imtiaz
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, Husson University, Bangor, Maine 04401, United States
| | - Jennifer L Newell-Caito
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine 04469, United States
| | - Samuel Caito
- Department of Basic Pharmaceutical Sciences, School of Pharmacy, Husson University, Bangor, Maine 04401, United States
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10
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Workflow for Segmentation of Caenorhabditis elegans from Fluorescence Images for the Quantitation of Lipids. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app112311420] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The small and transparent nematode Caenorhabditis elegans is increasingly employed for phenotypic in vivo chemical screens. The influence of compounds on worm body fat stores can be assayed with Nile red staining and imaging. Segmentation of C. elegans from fluorescence images is hereby a primary task. In this paper, we present an image-processing workflow that includes machine-learning-based segmentation of C. elegans directly from fluorescence images and quantifies their Nile red lipid-derived fluorescence. The segmentation is based on a J48 classifier using pixel entropies and is refined by size-thresholding. The accuracy of segmentation was >90% in our external validation. Binarization with a global threshold set to the brightness of the vehicle control group worms of each experiment allows a robust and reproducible quantification of worm fluorescence. The workflow is available as a script written in the macro language of imageJ, allowing the user additional manual control of classification results and custom specification settings for binarization. Our approach can be easily adapted to the requirements of other fluorescence image-based experiments with C. elegans.
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Grifola frondosa (Maitake) Extract Reduces Fat Accumulation and Improves Health Span in C. elegans through the DAF-16/FOXO and SKN-1/NRF2 Signalling Pathways. Nutrients 2021; 13:nu13113968. [PMID: 34836223 PMCID: PMC8620745 DOI: 10.3390/nu13113968] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 11/02/2021] [Accepted: 11/05/2021] [Indexed: 12/23/2022] Open
Abstract
In recent years, food ingredients rich in bioactive compounds have emerged as candidates to prevent excess adiposity and other metabolic complications characteristic of obesity, such as low-grade inflammation and oxidative status. Among them, fungi have gained popularity for their high polysaccharide content and other bioactive components with beneficial activities. Here, we use the C. elegans model to investigate the potential activities of a Grifola frondosa extract (GE), together with the underlying mechanisms of action. Our study revealed that GE represents an important source of polysaccharides and phenolic compounds with in vitro antioxidant activity. Treatment with our GE extract, which was found to be nongenotoxic through a SOS/umu test, significantly reduced the fat content of C. elegans, decreased the production of intracellular ROS and aging–lipofuscin pigment, and increased the lifespan of nematodes. Gene expression and mutant analyses demonstrated that the in vivo anti-obesity and antioxidant activities of GE were mediated through the daf-2/daf-16 and skn-1/nrf-2 signalling pathways, respectively. Taken together, our results suggest that our GE extract could be considered a potential functional ingredient for the prevention of obesity-related disturbances.
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12
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Methylmercury-Induced Metabolic Alterations in Caenorhabditis elegans Are Diet-Dependent. TOXICS 2021; 9:toxics9110287. [PMID: 34822679 PMCID: PMC8619518 DOI: 10.3390/toxics9110287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 09/22/2021] [Accepted: 10/29/2021] [Indexed: 01/12/2023]
Abstract
Methylmercury (MeHg) is a well-known neurotoxicant; however, its role in metabolic diseases has been gaining wider attention. Chronic exposure to MeHg in human populations shows an association with diabetes mellitus and metabolic syndrome (MS). As the incidences of both obesity and MS are on the rise globally, it is important to understand the potential role of MeHg in the development of the disease. There is a dearth of information on dietary interactions between MeHg and lipids, which play an important role in developing MS. We have previously shown that MeHg increases food seeking behaviors, lipid levels, fat storage, and pro-adipogenic gene expression in C. elegans fed the standard OP50 Escherichia coli diet. However, we hypothesized that these metabolic changes could be prevented if the worms were fed a bacterial diet lower in lipid content. We tested whether C. elegans developed metabolic alterations in response to MeHg if they were fed two alternative E. coli strains (HT115 and HB101) that are known absorb significantly less lipids from their media. Additionally, to explore the effect of a high-lipid and high-cholesterol diet on MeHg-induced metabolic dysfunction, we supplemented the OP50 strain with twice the standard concentration of cholesterol in the nematode growth media. Wild-type worms fed either the HB101 or HT115 diet were more resistant to MeHg than the worms fed the OP50 diet, showing a significant right-hand shift in the dose–response survival curve. Worms fed the OP50 diet supplemented with cholesterol were more sensitive to MeHg, showing a significant left-hand shift in the dose–response survival curve. Changes in sensitivity to MeHg by differential diet were not due to altered MeHg intake in the worms as measured by inductively coupled mass spectrometry. Worms fed the low-fat diets showed protection from MeHg-induced metabolic changes, including decreased food consumption, lower triglyceride content, and lower fat storage than the worms fed either of the higher-fat diets. Oxidative stress is a common characteristic of both MeHg exposure and high-fat diets. Worms fed either OP50 or OP50 supplemented with cholesterol and treated with MeHg had significantly higher levels of reactive oxygen species, carbonylated proteins, and loss of glutathione than the worms fed the HT115 or HB101 low-lipid diets. Taken together, our data suggest a synergistic effect of MeHg and dietary lipid levels on MeHg toxicity and fat metabolism in C. elegans, which may affect the ability of MeHg to cause metabolic dysfunction.
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13
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Méndez DA, Fabra MJ, Falcó I, Sánchez G, Aranaz P, Vettorazzi A, Ribas-Agustí A, González-Navarro CJ, Castellari M, Martínez-Abad A, López-Rubio A. Bioactive extracts from persimmon waste: influence of extraction conditions and ripeness. Food Funct 2021; 12:7428-7439. [PMID: 34190270 DOI: 10.1039/d1fo00457c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In this work, a bioactive persimmon extract was produced from discarded fruits. A central composite design was used to evaluate the effect of different extraction parameters and ripeness stages of persimmon fruits on the total phenolic content and antioxidant activity of the resulting extracts. Significantly greater phenolic contents were obtained from immature persimmon (IP) fruits. The optimum IP extract with the conditions set by the experimental design was industrially up-scaled and its composition and functional properties were evaluated and compared with those obtained under lab-scale conditions. Both extracts contained significant protein (>20%) and phenolic contents (∼11-27 mg GA/g dry extract) and displayed significant antiviral activity against murine norovirus and hepatitis A virus. Moreover, the extract showed no toxicity and significantly reduced the fat content and the cellular ageing of Caenorhabditis elegans (C. elegans) without affecting the worm development. These effects were mediated by down-regulation of fat-7, suggesting an anti-lipogenic activity of this extract.
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Affiliation(s)
- Daniel Alexander Méndez
- Food Safety and Preservation Department, Institute of Agrochemistry and Food Technology (IATA-CSIC), Valencia, Spain.
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14
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Cadena Del Castillo CE, Hannich JT, Kaech A, Chiyoda H, Brewer J, Fukuyama M, Færgeman NJ, Riezman H, Spang A. Patched regulates lipid homeostasis by controlling cellular cholesterol levels. Nat Commun 2021; 12:4898. [PMID: 34385431 PMCID: PMC8361143 DOI: 10.1038/s41467-021-24995-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 07/11/2021] [Indexed: 02/07/2023] Open
Abstract
Hedgehog (Hh) signaling is essential during development and in organ physiology. In the canonical pathway, Hh binding to Patched (PTCH) relieves the inhibition of Smoothened (SMO). Yet, PTCH may also perform SMO-independent functions. While the PTCH homolog PTC-3 is essential in C. elegans, worms lack SMO, providing an excellent model to probe non-canonical PTCH function. Here, we show that PTC-3 is a cholesterol transporter. ptc-3(RNAi) leads to accumulation of intracellular cholesterol and defects in ER structure and lipid droplet formation. These phenotypes were accompanied by a reduction in acyl chain (FA) length and desaturation. ptc-3(RNAi)-induced lethality, fat content and ER morphology defects were rescued by reducing dietary cholesterol. We provide evidence that cholesterol accumulation modulates the function of nuclear hormone receptors such as of the PPARα homolog NHR-49 and NHR-181, and affects FA composition. Our data uncover a role for PTCH in organelle structure maintenance and fat metabolism.
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Affiliation(s)
| | - J Thomas Hannich
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
- CeMM - Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Andres Kaech
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Hirohisa Chiyoda
- Laboratory of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Jonathan Brewer
- Department of Biochemistry and Molecular Biology, Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Masamitsu Fukuyama
- Laboratory of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Nils J Færgeman
- Department of Biochemistry and Molecular Biology, Villum Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Howard Riezman
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Anne Spang
- Biozentrum, University of Basel, Basel, Switzerland.
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15
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Caito SW, Newell-Caito J, Martell M, Crawford N, Aschner M. Methylmercury Induces Metabolic Alterations in Caenorhabditis elegans: Role for C/EBP Transcription Factor. Toxicol Sci 2021; 174:112-123. [PMID: 31851340 DOI: 10.1093/toxsci/kfz244] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Methylmercury (MeHg) is a well-known neurotoxicant; however, its role in metabolic diseases has been gaining wider attention. We have previously shown that MeHg causes metabolic alterations in Caenorhabditis elegans, leading to decreased nicotinamide adenine dinucleotide cofactor, mitochondrial dysfunction, and oxidative stress. We were, therefore, interested in whether MeHg also affects nutrient metabolism, particularly lipid homeostasis, which may contribute to the development of metabolic conditions such as obesity or metabolic syndrome (MS). RNA from wild-type worms exposed to MeHg was collected immediately after treatment and used for gene expression analysis by DNA microarray. MeHg differentially regulated 215 genes, 17 genes involved in lipid homeostasis, and 12 genes involved in carbohydrate homeostasis. Of particular interest was cebp-1, the worm ortholog to human C/EBP, a pro-adipogenic transcription factor implicated in MS. MeHg increased the expression of cebp-1 as well as pro-adipogenic transcription factors sbp-1 and nhr-49, triglyceride synthesis enzyme acl-6, and lipid transport proteins vit-2 and vit-6. Concurrent with the altered gene expression, MeHg increased triglyceride levels, lipid storage, and feeding behaviors. Worms expressing mutant cebp-1 were protected from MeHg-induced alterations in lipid content, feeding behaviors, and gene expression, highlighting the importance of this transcription factor in the worm's response to MeHg. Taken together, our data demonstrate that MeHg induces biochemical, metabolic, and behavioral changes in C. elegans that can lead to metabolic dysfunction.
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Affiliation(s)
- Samuel W Caito
- Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine
| | | | - Megan Martell
- Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine
| | - Nicole Crawford
- Department of Basic Pharmaceutical Sciences, Husson University School of Pharmacy, Bangor, Maine
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York
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16
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Aranaz P, Navarro-Herrera D, Zabala M, Romo-Hualde A, López-Yoldi M, Vizmanos JL, Milagro FI, González-Navarro CJ. Phenolic Compounds Reduce the Fat Content in Caenorhabditis elegans by Affecting Lipogenesis, Lipolysis, and Different Stress Responses. Pharmaceuticals (Basel) 2020; 13:E355. [PMID: 33143060 PMCID: PMC7693530 DOI: 10.3390/ph13110355] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/22/2020] [Accepted: 10/27/2020] [Indexed: 12/12/2022] Open
Abstract
Supplementation with bioactive compounds capable of regulating energy homeostasis is a promising strategy to manage obesity. Here, we have screened the ability of different phenolic compounds (myricetin, kaempferol, naringin, hesperidin, apigenin, luteolin, resveratrol, curcumin, and epicatechin) and phenolic acids (p-coumaric, ellagic, ferulic, gallic, and vanillic acids) regulating C. elegans fat accumulation. Resveratrol exhibited the strongest lipid-reducing activity, which was accompanied by the improvement of lifespan, oxidative stress, and aging, without affecting worm development. Whole-genome expression microarrays demonstrated that resveratrol affected fat mobilization, fatty acid metabolism, and unfolded protein response of the endoplasmic reticulum (UPRER), mimicking the response to calorie restriction. Apigenin induced the oxidative stress response and lipid mobilization, while vanillic acid affected the unfolded-protein response in ER. In summary, our data demonstrates that phenolic compounds exert a lipid-reducing activity in C. elegans through different biological processes and signaling pathways, including those related with lipid mobilization and fatty acid metabolism, oxidative stress, aging, and UPR-ER response. These findings open the door to the possibility of combining them in order to achieve complementary activity against obesity-related disorders.
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Affiliation(s)
- Paula Aranaz
- Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain; (P.A.); (D.N.-H.); (M.Z.); (A.R.-H.); (M.L.-Y.); (F.I.M.)
- Navarra Institute for Health Research (IdiSNA), 31008 Pamplona, Spain;
| | - David Navarro-Herrera
- Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain; (P.A.); (D.N.-H.); (M.Z.); (A.R.-H.); (M.L.-Y.); (F.I.M.)
- Department of Biochemistry and Genetics, School of Sciences, University of Navarra, 31008 Pamplona, Spain
| | - María Zabala
- Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain; (P.A.); (D.N.-H.); (M.Z.); (A.R.-H.); (M.L.-Y.); (F.I.M.)
| | - Ana Romo-Hualde
- Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain; (P.A.); (D.N.-H.); (M.Z.); (A.R.-H.); (M.L.-Y.); (F.I.M.)
| | - Miguel López-Yoldi
- Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain; (P.A.); (D.N.-H.); (M.Z.); (A.R.-H.); (M.L.-Y.); (F.I.M.)
| | - José Luis Vizmanos
- Navarra Institute for Health Research (IdiSNA), 31008 Pamplona, Spain;
- Department of Biochemistry and Genetics, School of Sciences, University of Navarra, 31008 Pamplona, Spain
| | - Fermín I. Milagro
- Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain; (P.A.); (D.N.-H.); (M.Z.); (A.R.-H.); (M.L.-Y.); (F.I.M.)
- Navarra Institute for Health Research (IdiSNA), 31008 Pamplona, Spain;
- Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición (CIBERObn), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Carlos J. González-Navarro
- Center for Nutrition Research, School of Pharmacy and Nutrition, University of Navarra, 31008 Pamplona, Spain; (P.A.); (D.N.-H.); (M.Z.); (A.R.-H.); (M.L.-Y.); (F.I.M.)
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17
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Inchaurraga L, Martínez-López AL, Martin-Arbella N, Irache JM. Zein-based nanoparticles for the oral delivery of insulin. Drug Deliv Transl Res 2020; 10:1601-1611. [PMID: 32514704 DOI: 10.1007/s13346-020-00796-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of this work was to evaluate oral nanocarriers, prepared from zein nanoparticles coated with a poly(anhydride)-thiamine conjugate (GT), for the delivery of insulin. Nanoparticles displayed a size of 250 nm with a negative surface charge, and an insulin loading of 80 μg/mg. Under simulated gastric conditions, GT-coated nanoparticles released a significantly lower amount of insulin than bare ones; whereas in simulated intestinal conditions, both types of nanoparticles displayed a similar behavior. The effect of insulin on the lipid metabolism of C. elegans under high glucose conditions, characterized by a reduction of the fat content, was also investigated. The effect was significantly higher for the nanoencapsulated forms of insulin than for the free protein (p < 0.001). This effect was two times higher for GT-coated nanoparticles than for bare ones. In rats, the hypoglycemic effect and the pharmacokinetic profile of insulin-loaded nanoparticles orally administered (50 IU/kg) were evaluated. The glycemia of animals slowly decreased reaching a minimum 6-10-h post-administration, with a maximum decrease of about 60%. The pharmacological availability of nanoencapsulated insulin was 13.5%. In serum, nanoparticles provided a maximum of insulin 4-h post-administration, and its relative oral bioavailability was 5.2% (compared with a sc formulation of insulin). Graphical abstract.
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Affiliation(s)
- Laura Inchaurraga
- NANO-VAC Research Group, Department of Chemistry and Pharmaceutical Technology, University of Navarra, C/Irunlarrea, 1, 31008, Pamplona, Spain
| | - Ana L Martínez-López
- NANO-VAC Research Group, Department of Chemistry and Pharmaceutical Technology, University of Navarra, C/Irunlarrea, 1, 31008, Pamplona, Spain
| | - Nekane Martin-Arbella
- NANO-VAC Research Group, Department of Chemistry and Pharmaceutical Technology, University of Navarra, C/Irunlarrea, 1, 31008, Pamplona, Spain
| | - Juan M Irache
- NANO-VAC Research Group, Department of Chemistry and Pharmaceutical Technology, University of Navarra, C/Irunlarrea, 1, 31008, Pamplona, Spain.
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18
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Jung Y, Kwon S, Ham S, Lee D, Park HH, Yamaoka Y, Jeong D, Artan M, Altintas O, Park S, Hwang W, Lee Y, Son HG, An SWA, Kim EJE, Seo M, Lee SV. Caenorhabditis elegans Lipin 1 moderates the lifespan-shortening effects of dietary glucose by maintaining ω-6 polyunsaturated fatty acids. Aging Cell 2020; 19:e13150. [PMID: 32475074 PMCID: PMC7294780 DOI: 10.1111/acel.13150] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/19/2020] [Accepted: 03/16/2020] [Indexed: 12/15/2022] Open
Abstract
Excessive glucose causes various diseases and decreases lifespan by altering metabolic processes, but underlying mechanisms remain incompletely understood. Here, we show that Lipin 1/LPIN-1, a phosphatidic acid phosphatase and a putative transcriptional coregulator, prevents life-shortening effects of dietary glucose on Caenorhabditis elegans. We found that depletion of lpin-1 decreased overall lipid levels, despite increasing the expression of genes that promote fat synthesis and desaturation, and downregulation of lipolysis. We then showed that knockdown of lpin-1 altered the composition of various fatty acids in the opposite direction of dietary glucose. In particular, the levels of two ω-6 polyunsaturated fatty acids (PUFAs), linoleic acid and arachidonic acid, were increased by knockdown of lpin-1 but decreased by glucose feeding. Importantly, these ω-6 PUFAs attenuated the short lifespan of glucose-fed lpin-1-inhibited animals. Thus, the production of ω-6 PUFAs is crucial for protecting animals from living very short under glucose-rich conditions.
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Affiliation(s)
- Yoonji Jung
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Sujeong Kwon
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Seokjin Ham
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Dongyeop Lee
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - Hae‐Eun H. Park
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Yasuyo Yamaoka
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - Dae‐Eun Jeong
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - Murat Artan
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - Ozlem Altintas
- School of Interdisciplinary Bioscience and Bioengineering Pohang University of Science and Technology Pohang South Korea
| | - Sangsoon Park
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - Wooseon Hwang
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - Yujin Lee
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Heehwa G. Son
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Seon Woo A. An
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Eun Ji E. Kim
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
| | - Mihwa Seo
- Department of Life Sciences Pohang University of Science and Technology Pohang South Korea
| | - Seung‐Jae V. Lee
- Department of Biological Sciences Korea Advanced Institute of Science and Technology Daejeon South Korea
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19
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Nhan JD, Curran SP. Metabolic Assessment of Lipid Abundance and Distribution. Aging (Albany NY) 2020; 2144:103-110. [DOI: 10.1007/978-1-0716-0592-9_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/10/2023]
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20
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Pino EC, Soukas AA. Quantitative Profiling of Lipid Species in Caenorhabditis elegans with Gas Chromatography-Mass Spectrometry. Methods Mol Biol 2020; 2144:111-123. [PMID: 32410029 DOI: 10.1007/978-1-0716-0592-9_10] [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] [Indexed: 03/25/2024]
Abstract
Gas chromatography-mass spectrometry (GC-MS) enables sensitive detection and relative quantification of fatty acids. In Caenorhabditis elegans, the use of GC-MS can corroborate findings from common staining methodologies, providing great resolution on the lipid species altered in abundance in aging, genetic mutants, or with dietary or pharmacologic manipulation. Here we describe a method to quantitate relative abundance of fatty acids in total worm lipid extracts, as well as a method that quantitates fatty acids following separation into neutral lipid pools (triacylglycerols and cholesteryl esters) versus more polar lipids (phospholipids) by solid-phase extraction (SPE).
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Affiliation(s)
- Elizabeth C Pino
- Center for Translational Epidemiology and Comparative Effectiveness Research, Boston University School of Medicine, Boston, MA, USA
| | - Alexander A Soukas
- Department of Medicine, Endocrine Division, and Diabetes Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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21
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Nhan JD, Turner CD, Anderson SM, Yen CA, Dalton HM, Cheesman HK, Ruter DL, Uma Naresh N, Haynes CM, Soukas AA, Pukkila-Worley R, Curran SP. Redirection of SKN-1 abates the negative metabolic outcomes of a perceived pathogen infection. Proc Natl Acad Sci U S A 2019; 116:22322-22330. [PMID: 31611372 PMCID: PMC6825279 DOI: 10.1073/pnas.1909666116] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Early host responses toward pathogens are essential for defense against infection. In Caenorhabditis elegans, the transcription factor, SKN-1, regulates cellular defenses during xenobiotic intoxication and bacterial infection. However, constitutive activation of SKN-1 results in pleiotropic outcomes, including a redistribution of somatic lipids to the germline, which impairs health and shortens lifespan. Here, we show that exposing C. elegans to Pseudomonas aeruginosa similarly drives the rapid depletion of somatic, but not germline, lipid stores. Modulating the epigenetic landscape refines SKN-1 activity away from innate immunity targets, which alleviates negative metabolic outcomes. Similarly, exposure to oxidative stress redirects SKN-1 activity away from pathogen response genes while restoring somatic lipid distribution. In addition, activating p38/MAPK signaling in the absence of pathogens, is sufficient to drive SKN-1-dependent loss of somatic fat. These data define a SKN-1- and p38-dependent axis for coordinating pathogen responses, lipid homeostasis, and survival and identify transcriptional redirection, rather than inactivation, as a mechanism for counteracting the pleiotropic consequences of aberrant transcriptional activity.
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Affiliation(s)
- James D Nhan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Christian D Turner
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Sarah M Anderson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Chia-An Yen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Hans M Dalton
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Hilary K Cheesman
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Dana L Ruter
- Biology Department, Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599
| | - Nandhitha Uma Naresh
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Cole M Haynes
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Alexander A Soukas
- Center for Human Genetic Research and Diabetes Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Read Pukkila-Worley
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655;
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089;
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
- Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
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22
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Jia R, Zhang J, Jia K. Neuroendocrine regulation of fat metabolism by autophagy gene atg-18 in C. elegans dauer larvae. FEBS Open Bio 2019; 9:1623-1631. [PMID: 31368651 PMCID: PMC6722879 DOI: 10.1002/2211-5463.12708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/10/2019] [Accepted: 07/31/2019] [Indexed: 12/21/2022] Open
Abstract
In environments with limited food and high population density, Caenorhabditis elegans larvae may enter the dauer stage, in which metabolism is shifted to fat accumulation to allow larvae to survive for months without food. Mutations in the insulin‐like receptor gene daf‐2 force C. elegans to constitutively form dauer larva at higher temperature. It has been reported that autophagy is required for fat accumulation in daf‐2 dauer larva. However, the mechanism underlying this process remains unknown. Here, we report that autophagy gene atg‐18 acts in a cell nonautonomous manner in neurons and intestinal cells to mediate the influence of daf‐2 signaling on fat metabolism. Moreover, ATG‐18 in chemosensory neurons plays a vital role in this metabolic process. Finally, we report that neuronal ATG‐18 functions through neurotransmitters to control fat storage in daf‐2 dauers, which suggests an essential role of autophagy in the neuroendocrine regulation of fat metabolism by insulin‐like signaling.
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Affiliation(s)
- Ray Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Jiuli Zhang
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Jupiter, FL, USA
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Aranaz P, Navarro-Herrera D, Romo-Hualde A, Zabala M, López-Yoldi M, González-Ferrero C, Gil AG, Alfredo Martinez J, Vizmanos JL, Milagro FI, González-Navarro CJ. Broccoli extract improves high fat diet-induced obesity, hepatic steatosis and glucose intolerance in Wistar rats. J Funct Foods 2019. [DOI: 10.1016/j.jff.2019.05.054] [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] Open
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Anderson SM, Cheesman HK, Peterson ND, Salisbury JE, Soukas AA, Pukkila-Worley R. The fatty acid oleate is required for innate immune activation and pathogen defense in Caenorhabditis elegans. PLoS Pathog 2019; 15:e1007893. [PMID: 31206555 PMCID: PMC6597122 DOI: 10.1371/journal.ppat.1007893] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 06/27/2019] [Accepted: 06/04/2019] [Indexed: 12/03/2022] Open
Abstract
Fatty acids affect a number of physiological processes, in addition to forming the building blocks of membranes and body fat stores. In this study, we uncover a role for the monounsaturated fatty acid oleate in the innate immune response of the nematode Caenorhabditis elegans. From an RNAi screen for regulators of innate immune defense genes, we identified the two stearoyl-coenzyme A desaturases that synthesize oleate in C. elegans. We show that the synthesis of oleate is necessary for the pathogen-mediated induction of immune defense genes. Accordingly, C. elegans deficient in oleate production are hypersusceptible to infection with diverse human pathogens, which can be rescued by the addition of exogenous oleate. However, oleate is not sufficient to drive protective immune activation. Together, these data add to the known health-promoting effects of monounsaturated fatty acids, and suggest an ancient link between nutrient stores, metabolism, and host susceptibility to bacterial infection. The evolution of multicellular organisms has been shaped by their interactions with pathogenic microorganisms. The microscopic nematode C. elegans eats bacteria for food and has evolved inducible immune defenses toward ingested pathogens that are coordinated within intestinal epithelial cells. C. elegans, therefore, presents a genetic system to characterize the requirements for the activation of innate immune defenses. Here, we show that the monounsaturated fatty acid oleate is necessary for the induction of innate immune defenses and for protection against bacterial pathogens, which defines a new link between metabolism and the regulation of anti-pathogen responses in a metazoan host.
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Affiliation(s)
- Sarah M. Anderson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Hilary K. Cheesman
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Nicholas D. Peterson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - J. Elizabeth Salisbury
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Alexander A. Soukas
- Center for Human Genomic Medicine and Diabetes Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States of America
| | - Read Pukkila-Worley
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA, United States of America
- * E-mail:
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Doshi S, Braganza V. Ameliorative effect of Argyreia boseana Sant. & Pat. on stress in C. elegans. J Ayurveda Integr Med 2018; 11:147-152. [PMID: 30448258 PMCID: PMC7329712 DOI: 10.1016/j.jaim.2017.11.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/21/2017] [Accepted: 11/27/2017] [Indexed: 12/05/2022] Open
Abstract
Background Argyreia boseana Santapau and Patel commonly known as Kumbharao belongs to the family of Convolvulaceae. The plant is rare in distribution and found chiefly in the dediapada region of Gujarat. Traditionally it is used by the tribals of south Gujarat forest region in the treatment of various diseases of the nervous system. In order to study the scientific basis of the plants effect we set out to investigate the effect of the plant on ageing organisms and used Caenorhabditis elegans as a model. Objective To evaluate the effect of crude extract of leaves, prepared from A. boseana on oxidative stress, thermal stress, longevity and in vivo gene expression of C. elegans. Material and Methods Plant extracts was prepared by sonication based method using solvent ethanol:water. Longevity experiments were carried out in liquid S media. Oxidative stress was induced by paraquat. Result Results indicate no increase in the normal life span of C. elegans. However, A. boseana significantly induces stress tolerance and increased the mean lifespan of worms during thermal and oxidative stress. Additionally A. boseana was also able to up regulate the stress associated gene gst-4. Conclusion Thus the present study, for the first time, unravels the anti-stress and ROS modulating effect of A. boseana.
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Affiliation(s)
- Shital Doshi
- St. Xavier's College, Navarangpura, Ahmedabad, 380009, India.
| | - Vincent Braganza
- Loyola Centre for Research and Development, St. Xavier's College Campus, Ahmedabad, 380009, India
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Kaplan REW, Webster AK, Chitrakar R, Dent JA, Baugh LR. Food perception without ingestion leads to metabolic changes and irreversible developmental arrest in C. elegans. BMC Biol 2018; 16:112. [PMID: 30296941 PMCID: PMC6176503 DOI: 10.1186/s12915-018-0579-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/24/2018] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Developmental physiology is very sensitive to nutrient availability. For instance, in the nematode Caenorhabditis elegans, newly hatched L1-stage larvae require food to initiate postembryonic development. In addition, larvae arrested in the dauer diapause, a non-feeding state of developmental arrest that occurs during the L3 stage, initiate recovery when exposed to food. Despite the essential role of food in C. elegans development, the contribution of food perception versus ingestion on physiology has not been delineated. RESULTS We used a pharmacological approach to uncouple the effects of food (bacteria) perception and ingestion in C. elegans. Perception was not sufficient to promote postembryonic development in L1-stage larvae. However, L1 larvae exposed to food without ingestion failed to develop upon return to normal culture conditions, instead displaying an irreversible arrest phenotype. Inhibition of gene expression during perception rescued subsequent development, demonstrating that the response to perception without feeding is deleterious. Perception altered DAF-16/FOXO subcellular localization, reflecting activation of insulin/IGF signaling (IIS). The insulin-like peptide daf-28 was specifically required, suggesting perception in chemosensory neurons, where it is expressed, regulates peptide synthesis and possibly secretion. However, genetic manipulation of IIS did not modify the irreversible arrest phenotype caused by food perception, revealing that wild-type function of the IIS pathway is not required to produce this phenotype and that other pathways affected by perception of food in the absence of its ingestion are likely to be involved. Gene expression and Nile red staining showed that food perception could alter lipid metabolism and storage. We found that starved larvae sense environmental polypeptides, with similar molecular and developmental effects as perception of bacteria. Environmental polypeptides also promoted recovery from dauer diapause, suggesting that perception of polypeptides plays an important role in the life history of free-living nematodes. CONCLUSIONS We conclude that actual ingestion of food is required to initiate postembryonic development in C. elegans. We also conclude that polypeptides are perceived as a food-associated cue in this and likely other animals, initiating a signaling and gene regulatory cascade that alters metabolism in anticipation of feeding and development, but that this response is detrimental if feeding does not occur.
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Affiliation(s)
- Rebecca E W Kaplan
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA
| | - Amy K Webster
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA
| | - Rojin Chitrakar
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA
| | - Joseph A Dent
- Department of Biology, McGill University, Montreal, QC, H3A 1B1, Canada
| | - L Ryan Baugh
- Department of Biology, Duke University, Box 90338, Durham, NC, 27708-0338, USA.
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Webster CM, Pino EC, Carr CE, Wu L, Zhou B, Cedillo L, Kacergis MC, Curran SP, Soukas AA. Genome-wide RNAi Screen for Fat Regulatory Genes in C. elegans Identifies a Proteostasis-AMPK Axis Critical for Starvation Survival. Cell Rep 2018; 20:627-640. [PMID: 28723566 DOI: 10.1016/j.celrep.2017.06.068] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 05/11/2017] [Accepted: 06/22/2017] [Indexed: 12/26/2022] Open
Abstract
Organisms must execute metabolic defenses to survive nutrient deprivation. We performed a genome-wide RNAi screen in Caenorhabditis elegans to identify fat regulatory genes indispensable for starvation resistance. Here, we show that opposing proteostasis pathways are principal determinants of starvation survival. Reduced function of cytoplasmic aminoacyl tRNA synthetases (ARS genes) increases fat mass and extends starvation survival, whereas reduced proteasomal function reduces fat and starvation survival. These opposing pathways converge on AMP-activated protein kinase (AMPK) as the critical effector of starvation defenses. Extended starvation survival in ARS deficiency is dependent upon increased proteasome-mediated activation of AMPK. When the proteasome is inhibited, neither starvation nor ARS deficiency can fully activate AMPK, leading to greatly diminished starvation survival. Thus, activity of the proteasome and AMPK are mechanistically linked and highly correlated with starvation resistance. Conversely, aberrant activation of the proteostasis-AMPK axis during nutritional excess may have implications for obesity and cardiometabolic diseases.
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Affiliation(s)
- Christopher M Webster
- Department of Medicine, Center for Genomic Medicine and Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Elizabeth C Pino
- Department of Medicine, Center for Genomic Medicine and Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Christopher E Carr
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Lianfeng Wu
- Department of Medicine, Center for Genomic Medicine and Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Ben Zhou
- Department of Medicine, Center for Genomic Medicine and Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Lucydalila Cedillo
- Department of Medicine, Center for Genomic Medicine and Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA; Graduate Program in Biomedical and Biological Sciences, Harvard Medical School, Boston, MA 02115, USA
| | - Michael C Kacergis
- Department of Medicine, Center for Genomic Medicine and Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Alexander A Soukas
- Department of Medicine, Center for Genomic Medicine and Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Medicine, Harvard Medical School, Boston, MA 02114, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA.
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Escorcia W, Ruter DL, Nhan J, Curran SP. Quantification of Lipid Abundance and Evaluation of Lipid Distribution in Caenorhabditis elegans by Nile Red and Oil Red O Staining. J Vis Exp 2018. [PMID: 29553519 DOI: 10.3791/57352] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Caenorhabditis elegans is an exceptional model organism in which to study lipid metabolism and energy homeostasis. Many of its lipid genes are conserved in humans and are associated with metabolic syndrome or other diseases. Examination of lipid accumulation in this organism can be carried out by fixative dyes or label-free methods. Fixative stains like Nile red and oil red O are inexpensive, reliable ways to quantitatively measure lipid levels and to qualitatively observe lipid distribution across tissues, respectively. Moreover, these stains allow for high-throughput screening of various lipid metabolism genes and pathways. Additionally, their hydrophobic nature facilitates lipid solubility, reduces interaction with surrounding tissues, and prevents dissociation into the solvent. Though these methods are effective at examining general lipid content, they do not provide detailed information about the chemical composition and diversity of lipid deposits. For these purposes, label-free methods such as GC-MS and CARS microscopy are better suited, their costs notwithstanding.
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Affiliation(s)
- Wilber Escorcia
- Leonard Davis School of Gerontology, University of Southern California
| | - Dana L Ruter
- Leonard Davis School of Gerontology, University of Southern California; Molecular & Computational Biology Section, University of Southern California; Integrative Program for Biological & Genome Sciences, University of North Carolina at Chapel Hill
| | - James Nhan
- Leonard Davis School of Gerontology, University of Southern California; Molecular & Computational Biology Section, University of Southern California
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California; Molecular & Computational Biology Section, University of Southern California;
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29
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Pradhan A, Olsson PE, Jass J. Di(2-ethylhexyl) phthalate and diethyl phthalate disrupt lipid metabolism, reduce fecundity and shortens lifespan of Caenorhabditis elegans. CHEMOSPHERE 2018; 190:375-382. [PMID: 29020644 DOI: 10.1016/j.chemosphere.2017.09.123] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 09/13/2017] [Accepted: 09/26/2017] [Indexed: 05/22/2023]
Abstract
The widespread use of phthalates is of major concern as they have adverse effects on many different physiological functions, including reproduction, metabolism and cell differentiation. The aim of this study was to compare the toxicity of the widely-used di (2-ethydlhexyl) phthalate (DEHP) with its substitute, diethyl phthalate (DEP). We analyzed the toxicity of these two phthalates using Caenorhabditis elegans as a model system. Gene expression analysis following exposure during the L1 to young adult stage showed that DEHP and DEP alter the expression of genes involved in lipid metabolism and stress response. Genes associated with lipid metabolism, including fasn-1, pod-2, fat-5, acs-6 and sbp-1, and vitellogenin were upregulated. Among the stress response genes, ced-1 wah-1, daf-21 and gst-4 were upregulated, while ctl-1, cdf-2 and the heat shock proteins (hsp-16.1, hsp-16.48 and sip-1) were downregulated. Lipid staining revealed that DEHP significantly increased lipid content following 1 μM exposure, however, DEP required 10 μM exposure to elicit an effect. Both DEHP and DEP reduced the fecundity at 1 μM concentration. Lifespan analysis indicated that DEHP and DEP reduced the average lifespan from 14 days in unexposed worms to 13 and 12 days, respectively. Expression of lifespan associated genes showed a correlation to shortened lifespan in the exposed groups. As reported previously, our data also indicates that the banned DEHP is toxic to C. elegans, however its substitute DEP has not been previously tested in this model organism and our data revealed that DEP is equally potent as DEHP in regulating C. elegans physiological functions.
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Affiliation(s)
- Ajay Pradhan
- Biology, the Life Science Center, School of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden.
| | - Per-Erik Olsson
- Biology, the Life Science Center, School of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden
| | - Jana Jass
- Biology, the Life Science Center, School of Science and Technology, Örebro University, SE-701 82 Örebro, Sweden
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The MXL-3/SBP-1 Axis Is Responsible for Glucose-Dependent Fat Accumulation in C. elegans. Genes (Basel) 2017; 8:genes8110307. [PMID: 29113111 PMCID: PMC5704220 DOI: 10.3390/genes8110307] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 12/26/2022] Open
Abstract
Chronic exposure to elevated glucose levels leads to fatty acid accumulation, which promotes the development of metabolic diseases such as obesity and type 2 diabetes. MXL-3 is a conserved transcriptional factor that modulates the inhibition of lipolysis in Caenorhabditis elegans. However, the role of MXL-3 in lipid metabolism during nutrient excess remains unknown. We hypothesized that inhibition of MXL-3 prevents glucose-dependent fat accumulation. Nematodes from wild-type N2, MXL-3::GFP and sbp-1 or mxl-3 null strains were grown on standard, high glucose or high glucose plus metformin plates for 24 h. Using laser-scanning confocal microscopy, we monitored the glucose-induced activation of MXL-3 labeled with GFP (MXL-3::GFP). Lipid levels were determined by Oil Red O (ORO) staining and gas chromatography/mass spectrometry, and gene expression was assessed by qRT-PCR. We found that high glucose activated MXL-3 by increasing its rate of nuclear entry, which in turn increased lipid levels via sterol regulatory element-binding protein (SBP-1). This activated critical genes that synthesize long chain unsaturated fatty acids (MUFAs and PUFAs) and repress lipolytic genes. Interestingly, the anti-diabetic drug metformin inhibited MXL-3 activation and subsequently prevented glucose-dependent fat accumulation. These findings highlight the importance of the MXL-3/SBP-1 axis in the regulation of lipid metabolism during nutritional excess and provide new insight into the mechanism by which metformin prevents lipid accumulation. This study also suggests that inhibition of MXL-3 may serve as a potential target for the treatment of chronic metabolic diseases, including obesity, type 2 diabetes, and cardiovascular disease.
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Watts JL, Ristow M. Lipid and Carbohydrate Metabolism in Caenorhabditis elegans. Genetics 2017; 207:413-446. [PMID: 28978773 PMCID: PMC5629314 DOI: 10.1534/genetics.117.300106] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 08/02/2017] [Indexed: 12/14/2022] Open
Abstract
Lipid and carbohydrate metabolism are highly conserved processes that affect nearly all aspects of organismal biology. Caenorhabditis elegans eat bacteria, which consist of lipids, carbohydrates, and proteins that are broken down during digestion into fatty acids, simple sugars, and amino acid precursors. With these nutrients, C. elegans synthesizes a wide range of metabolites that are required for development and behavior. In this review, we outline lipid and carbohydrate structures as well as biosynthesis and breakdown pathways that have been characterized in C. elegans We bring attention to functional studies using mutant strains that reveal physiological roles for specific lipids and carbohydrates during development, aging, and adaptation to changing environmental conditions.
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Affiliation(s)
- Jennifer L Watts
- School of Molecular Biosciences and Center for Reproductive Biology, Washington State University, Pullman, Washington 99164
| | - Michael Ristow
- Energy Metabolism Laboratory, Institute of Translational Medicine, Department of Health Sciences and Technology, Swiss Federal Institute of Technology Zurich, 8603 Schwerzenbach-Zurich, Switzerland
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Kearn J, Lilley C, Urwin P, O'Connor V, Holden-Dye L. Progressive metabolic impairment underlies the novel nematicidal action of fluensulfone on the potato cyst nematode Globodera pallida. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2017; 142:83-90. [PMID: 29107251 DOI: 10.1016/j.pestbp.2017.01.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/05/2017] [Accepted: 01/12/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Fluensulfone is a new nematicide with an excellent profile of selective toxicity against plant parasitic nematodes. Here, its effects on the physiology and biochemistry of the potato cyst nematode Globodera pallida have been investigated and comparisons made with its effect on the life-span of the free-living nematode Caenorhabditis elegans to provide insight into its mode of action and its selective toxicity. RESULTS Fluensulfone exerts acute effects (≤1h; ≥100μM) on stylet thrusting and motility of hatched second stage G. pallida juveniles (J2s). Chronic exposure to lower concentrations of fluensulfone (≥3days; ≤30μM), reveals a slowly developing metabolic insult in which G. pallida J2s sequentially exhibit a reduction in motility, loss of a metabolic marker for cell viability, high lipid content and tissue degeneration prior to death. These effects are absent in adults and dauers of the model genetic nematode Caenorhabditis elegans. CONCLUSION The nematicidal action of fluensulfone follows a time-course which progresses from an early impact on motility through to an accumulating metabolic impairment, an inability to access lipid stores and death.
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Affiliation(s)
- James Kearn
- Biological Sciences, Building 85, University Road, University of Southampton, Southampton SO17 1BJ, UK
| | - Catherine Lilley
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Peter Urwin
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Vincent O'Connor
- Biological Sciences, Building 85, University Road, University of Southampton, Southampton SO17 1BJ, UK
| | - Lindy Holden-Dye
- Biological Sciences, Building 85, University Road, University of Southampton, Southampton SO17 1BJ, UK.
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33
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Jeong H, Paik YK. MGL-1 on AIY neurons translates starvation to reproductive plasticity via neuropeptide signaling in Caenorhabditis elegans. Dev Biol 2017; 430:80-89. [DOI: 10.1016/j.ydbio.2017.08.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 08/09/2017] [Indexed: 11/28/2022]
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34
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Wu L, Zhou B, Oshiro-Rapley N, Li M, Paulo JA, Webster CM, Mou F, Kacergis MC, Talkowski ME, Carr CE, Gygi SP, Zheng B, Soukas AA. An Ancient, Unified Mechanism for Metformin Growth Inhibition in C. elegans and Cancer. Cell 2017; 167:1705-1718.e13. [PMID: 27984722 DOI: 10.1016/j.cell.2016.11.055] [Citation(s) in RCA: 121] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Revised: 10/07/2016] [Accepted: 11/29/2016] [Indexed: 01/28/2023]
Abstract
Metformin has utility in cancer prevention and treatment, though the mechanisms for these effects remain elusive. Through genetic screening in C. elegans, we uncover two metformin response elements: the nuclear pore complex (NPC) and acyl-CoA dehydrogenase family member-10 (ACAD10). We demonstrate that biguanides inhibit growth by inhibiting mitochondrial respiratory capacity, which restrains transit of the RagA-RagC GTPase heterodimer through the NPC. Nuclear exclusion renders RagC incapable of gaining the GDP-bound state necessary to stimulate mTORC1. Biguanide-induced inactivation of mTORC1 subsequently inhibits growth through transcriptional induction of ACAD10. This ancient metformin response pathway is conserved from worms to humans. Both restricted nuclear pore transit and upregulation of ACAD10 are required for biguanides to reduce viability in melanoma and pancreatic cancer cells, and to extend C. elegans lifespan. This pathway provides a unified mechanism by which metformin kills cancer cells and extends lifespan, and illuminates potential cancer targets. PAPERCLIP.
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Affiliation(s)
- Lianfeng Wu
- Department of Medicine, Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Center for Human Genetic Research, 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
| | - Ben Zhou
- Department of Medicine, Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Center for Human Genetic Research, 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
| | - Noriko Oshiro-Rapley
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Man Li
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Joao A Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Christopher M Webster
- Department of Medicine, Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Center for Human Genetic Research, 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
| | - Fan Mou
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Michael C Kacergis
- Department of Medicine, Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Michael E Talkowski
- Center for Human Genetic Research, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Christopher E Carr
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Bin Zheng
- Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Alexander A Soukas
- Department of Medicine, Diabetes Unit, Massachusetts General Hospital, Boston, MA 02114, USA; Center for Human Genetic Research, 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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35
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Han S, Schroeder EA, Silva-García CG, Hebestreit K, Mair WB, Brunet A. Mono-unsaturated fatty acids link H3K4me3 modifiers to C. elegans lifespan. Nature 2017; 544:185-190. [PMID: 28379943 PMCID: PMC5391274 DOI: 10.1038/nature21686] [Citation(s) in RCA: 208] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/02/2017] [Indexed: 12/23/2022]
Abstract
Chromatin and metabolic states both influence lifespan, but how they interact in lifespan regulation is largely unknown. The COMPASS chromatin complex, which trimethylates lysine 4 on histone H3 (H3K4me3), regulates lifespan in Caenorhabditis elegans. However, the mechanism by which H3K4me3 modifiers affect longevity, and whether this mechanism involves metabolic changes, remain unclear. Here we show that a deficiency in H3K4me3 methyltransferase, which extends lifespan, promotes fat accumulation in worms with a specific enrichment of mono-unsaturated fatty acids (MUFAs). This fat metabolism switch in H3K4me3 methyltransferase-deficient worms is mediated at least in part by the downregulation of germline targets, including S6 kinase, and by the activation of an intestinal transcriptional network that upregulates delta-9 fatty acid desaturases. Notably, the accumulation of MUFAs is necessary for the lifespan extension of H3K4me3 methyltransferase-deficient worms, and dietary MUFAs are sufficient to extend lifespan. Given the conservation of lipid metabolism, dietary or endogenous MUFAs could extend lifespan and healthspan in other species, including mammals.
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Affiliation(s)
- Shuo Han
- Department of Genetics, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA.,Genetics Graduate Program, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA
| | - Elizabeth A Schroeder
- Department of Genetics, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA
| | - Carlos G Silva-García
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Katja Hebestreit
- Department of Genetics, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA
| | - William B Mair
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Anne Brunet
- Department of Genetics, Stanford University, 300 Pasteur Drive, Stanford, California 94305, USA.,Glenn Laboratories for the Biology of Aging, Stanford University, Stanford, California 94305, USA
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The ETS-5 transcription factor regulates activity states in Caenorhabditis elegans by controlling satiety. Proc Natl Acad Sci U S A 2017; 114:E1651-E1658. [PMID: 28193866 DOI: 10.1073/pnas.1610673114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Animal behavior is shaped through interplay among genes, the environment, and previous experience. As in mammals, satiety signals induce quiescence in Caenorhabditis elegans Here we report that the C. elegans transcription factor ETS-5, an ortholog of mammalian FEV/Pet1, controls satiety-induced quiescence. Nutritional status has a major influence on C. elegans behavior. When foraging, food availability controls behavioral state switching between active (roaming) and sedentary (dwelling) states; however, when provided with high-quality food, C. elegans become sated and enter quiescence. We show that ETS-5 acts to promote roaming and inhibit quiescence by setting the internal "satiety quotient" through fat regulation. Acting from the ASG and BAG sensory neurons, we show that ETS-5 functions in a complex network with serotonergic and neuropeptide signaling pathways to control food-regulated behavioral state switching. Taken together, our results identify a neuronal mechanism for controlling intestinal fat stores and organismal behavioral states in C. elegans, and establish a paradigm for the elucidation of obesity-relevant mechanisms.
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37
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Pradhan A, Hammerquist AM, Khanna A, Curran SP. The C-Box Region of MAF1 Regulates Transcriptional Activity and Protein Stability. J Mol Biol 2016; 429:192-207. [PMID: 27986570 DOI: 10.1016/j.jmb.2016.12.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 11/15/2016] [Accepted: 12/08/2016] [Indexed: 12/26/2022]
Abstract
MAF1 is a conserved negative regulator of RNA polymerase (pol) III and intracellular lipid homeostasis across species. Here, we show that the MAF1 C-box region negatively regulates its activity. Mutations in Caenorhabditis elegans mafr-1 that truncate the C-box retain the ability to inhibit the transcription of RNA pol III targets, reduce lipid biogenesis, and lower reproductive output. In human cells, C-box deletion of MAF1 leads to increased MAF1 nuclear localization and enhanced repression of ACC1 and FASN, but with impaired repression of RNA pol III targets. Surprisingly, C-box mutations render MAF1 insensitive to rapamycin, further defining a regulatory role for this region. Two MAF1 species, MAF1L and MAF1S, are regulated by the C-box YSY motif, which, when mutated, alters species stoichiometry and proteasome-dependent turnover of nuclear MAF1. Our results reveal a role for the C-box region as a critical determinant of MAF1 stability, activity, and response to cellular stress.
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Affiliation(s)
- Ajay Pradhan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA
| | - Amy M Hammerquist
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Akshat Khanna
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA.
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38
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Kuzmic M, Javot H, Bonzom JM, Lecomte-Pradines C, Radman M, Garnier-Laplace J, Frelon S. In situ visualization of carbonylation and its co-localization with proteins, lipids, DNA and RNA in Caenorhabditis elegans. Free Radic Biol Med 2016; 101:465-474. [PMID: 27840319 DOI: 10.1016/j.freeradbiomed.2016.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 10/28/2016] [Accepted: 11/03/2016] [Indexed: 11/26/2022]
Abstract
All key biological macromolecules are susceptible to carbonylation - an irreparable oxidative damage with deleterious biological consequences. Carbonyls in proteins, lipids and DNA from cell extracts have been used as a biomarker of oxidative stress and aging, but formation of insoluble aggregates by carbonylated proteins precludes quantification. Since carbonylated proteins correlate with and become a suspected cause of morbidity and mortality in some organisms, there is a need for their accurate quantification and localization. Using appropriate fluorescent probes, we have developed an in situ detection of total proteins, DNA, RNA, lipids and carbonyl groups at the level of the whole organism. In C. elegans, we found that after UV irradiation carbonylation co-localizes mainly with proteins and, to a lesser degree, with DNA, RNA and lipids. The method efficiency was illustrated by carbonylation induction assessment over 5 different UV doses. The procedure enables the monitoring of carbonylation in the nematode C. elegans during stress, aging and disease along its life cycle including the egg stage.
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Affiliation(s)
- Mira Kuzmic
- Institut de radioprotection et de sûreté nucléaire, Cadarache, 13115 Saint Paul lez Durance cedex, France; Mediterranean Institute for Life Sciences, Mestrovicevo Setaliste 45, 21000 Split, Croatia
| | - Hélène Javot
- CEA, BIAM, Lab Biol Develop Plantes, Saint-Paul-lez-DurIncreased carbonylation, protein aance F-13108, France; CNRS, UMR 7265 Biol Veget & Microbiol Environ, Saint-Paul-lez-Durance F-13108, France; Aix Marseille Université, BVME UMR7265, Marseille F-13284, France
| | - Jean-Marc Bonzom
- Institut de radioprotection et de sûreté nucléaire, Cadarache, 13115 Saint Paul lez Durance cedex, France
| | - Catherine Lecomte-Pradines
- Institut de radioprotection et de sûreté nucléaire, Cadarache, 13115 Saint Paul lez Durance cedex, France
| | - Miroslav Radman
- Mediterranean Institute for Life Sciences, Mestrovicevo Setaliste 45, 21000 Split, Croatia
| | - Jacqueline Garnier-Laplace
- Institut de radioprotection et de sûreté nucléaire, Cadarache, 13115 Saint Paul lez Durance cedex, France
| | - Sandrine Frelon
- Institut de radioprotection et de sûreté nucléaire, Cadarache, 13115 Saint Paul lez Durance cedex, France.
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Wang L, Xu F, Wang G, Wang X, Liang A, Huang H, Sun F. C30F12.4 influences oogenesis, fat metabolism, and lifespan in C. elegans. Protein Cell 2016; 7:714-721. [PMID: 27638466 PMCID: PMC5055490 DOI: 10.1007/s13238-016-0308-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 07/19/2016] [Indexed: 11/25/2022] Open
Abstract
Reproduction, fat metabolism, and longevity are intertwined regulatory axes; recent studies in C. elegans have provided evidence that these processes are directly coupled. However, the mechanisms by which they are coupled and the reproductive signals modulating fat metabolism and lifespan are poorly understood. Here, we find that an oogenesis-enriched gene, c30f12.4, is specifically expressed and located in germ cells and early embryos; when the gene is knocked out, oogenesis is disrupted and brood size is decreased. In addition to the reproductive phenotype, we find that the loss of c30f12.4 alters fat metabolism, resulting in decreased fat storage and smaller lipid droplets. Meanwhile, c30f12.4 mutant worms display a shortened lifespan. Our results highlight an important role for c30f12.4 in regulating reproduction, fat homeostasis, and aging in C. elegans, which helps us to better understand the relationship between these processes.
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Affiliation(s)
- Lu Wang
- International Peace Maternity & Child Health Hospital, Shanghai Key laboratory for Reproductive Medicine, School of Medicine, Institute of Embryo-Fetal Original Adult Disease, Shanghai Jiaotong University, Shanghai, 200030, China
| | - Fei Xu
- School of Life Sciences, University of Science and Technology of China, Hefei, 230026, China
| | - Guishuan Wang
- International Peace Maternity & Child Health Hospital, Shanghai Key laboratory for Reproductive Medicine, School of Medicine, Institute of Embryo-Fetal Original Adult Disease, Shanghai Jiaotong University, Shanghai, 200030, China
| | - Xiaorong Wang
- International Peace Maternity & Child Health Hospital, Shanghai Key laboratory for Reproductive Medicine, School of Medicine, Institute of Embryo-Fetal Original Adult Disease, Shanghai Jiaotong University, Shanghai, 200030, China
| | - Ajuan Liang
- International Peace Maternity & Child Health Hospital, Shanghai Key laboratory for Reproductive Medicine, School of Medicine, Institute of Embryo-Fetal Original Adult Disease, Shanghai Jiaotong University, Shanghai, 200030, China
| | - Hefeng Huang
- International Peace Maternity & Child Health Hospital, Shanghai Key laboratory for Reproductive Medicine, School of Medicine, Institute of Embryo-Fetal Original Adult Disease, Shanghai Jiaotong University, Shanghai, 200030, China.
| | - Fei Sun
- International Peace Maternity & Child Health Hospital, Shanghai Key laboratory for Reproductive Medicine, School of Medicine, Institute of Embryo-Fetal Original Adult Disease, Shanghai Jiaotong University, Shanghai, 200030, China.
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40
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DAF-16 and TCER-1 Facilitate Adaptation to Germline Loss by Restoring Lipid Homeostasis and Repressing Reproductive Physiology in C. elegans. PLoS Genet 2016; 12:e1005788. [PMID: 26862916 PMCID: PMC4749232 DOI: 10.1371/journal.pgen.1005788] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 12/16/2015] [Indexed: 12/22/2022] Open
Abstract
Elimination of the proliferating germline extends lifespan in C. elegans. This phenomenon provides a unique platform to understand how complex metazoans retain metabolic homeostasis when challenged with major physiological perturbations. Here, we demonstrate that two conserved transcription regulators essential for the longevity of germline-less adults, DAF-16/FOXO3A and TCER-1/TCERG1, concurrently enhance the expression of multiple genes involved in lipid synthesis and breakdown, and that both gene classes promote longevity. Lipidomic analyses revealed that key lipogenic processes, including de novo fatty acid synthesis, triglyceride production, desaturation and elongation, are augmented upon germline removal. Our data suggest that lipid anabolic and catabolic pathways are coordinately augmented in response to germline loss, and this metabolic shift helps preserve lipid homeostasis. DAF-16 and TCER-1 also perform essential inhibitory functions in germline-ablated animals. TCER-1 inhibits the somatic gene-expression program that facilitates reproduction and represses anti-longevity genes, whereas DAF-16 impedes ribosome biogenesis. Additionally, we discovered that TCER-1 is critical for optimal fertility in normal adults, suggesting that the protein acts as a switch supporting reproductive fitness or longevity depending on the presence or absence of the germline. Collectively, our data offer insights into how organisms adapt to changes in reproductive status, by utilizing the activating and repressive functions of transcription factors and coordinating fat production and degradation. The balance between production and breakdown of fats is critical for health, especially during reproduction-related changes such as onset of puberty or menopause. However, little is known about how animals retain a balanced metabolism when undergoing major life events. Here, we have used a C. elegans mutant that successfully adapts to loss of reproductive cells to address this question. Our data suggest that the conserved proteins DAF-16/FOXO3A and TCER-1/TCERG1 mediate a coordinated increase in fat synthesis and degradation when the reproductive cells are lost. This coupling likely helps the animal to manage the lipids that would have been deposited in eggs as yolk, thus preventing metabolic disarray. These proteins also inhibit processes that would have normally supported reproduction. Together the activities of these transcription regulators allow the mutant to convert a debilitating loss of fertility into improved health and longevity. We also report that TCER-1 promotes reproductive health in normal adults, whereas when procreation is impeded, it switches roles to repress fertility and enhance lipid equilibrium. These observations offer insights into how complex organisms coordinate their metabolism to suit their reproductive needs.
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41
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Moreno-Arriola E, EL Hafidi M, Ortega-Cuéllar D, Carvajal K. AMP-Activated Protein Kinase Regulates Oxidative Metabolism in Caenorhabditis elegans through the NHR-49 and MDT-15 Transcriptional Regulators. PLoS One 2016; 11:e0148089. [PMID: 26824904 PMCID: PMC4732773 DOI: 10.1371/journal.pone.0148089] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 01/12/2016] [Indexed: 12/25/2022] Open
Abstract
Cellular energy regulation relies on complex signaling pathways that respond to fuel availability and metabolic demands. Dysregulation of these networks is implicated in the development of human metabolic diseases such as obesity and metabolic syndrome. In Caenorhabditis elegans the AMP-activated protein kinase, AAK, has been associated with longevity and stress resistance; nevertheless its precise role in energy metabolism remains elusive. In the present study, we find an evolutionary conserved role of AAK in oxidative metabolism. Similar to mammals, AAK is activated by AICAR and metformin and leads to increased glycolytic and oxidative metabolic fluxes evidenced by an increase in lactate levels and mitochondrial oxygen consumption and a decrease in total fatty acids and lipid storage, whereas augmented glucose availability has the opposite effects. We found that these changes were largely dependent on the catalytic subunit AAK-2, since the aak-2 null strain lost the observed metabolic actions. Further results demonstrate that the effects due to AAK activation are associated to SBP-1 and NHR-49 transcriptional factors and MDT-15 transcriptional co-activator, suggesting a regulatory pathway that controls oxidative metabolism. Our findings establish C. elegans as a tractable model system to dissect the relationship between distinct molecules that play a critical role in the regulation of energy metabolism in human metabolic diseases.
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Affiliation(s)
| | - Mohammed EL Hafidi
- Departamento de Biomedicina Cardiovascular, Instituto Nacional de Cardiología, Mexico City, Mexico
| | - Daniel Ortega-Cuéllar
- Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Mexico City, Mexico
| | - Karla Carvajal
- Laboratorio de Nutrición Experimental, Instituto Nacional de Pediatría, Mexico City, Mexico
- * E-mail:
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42
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Lynn DA, Dalton HM, Sowa JN, Wang MC, Soukas AA, Curran SP. Omega-3 and -6 fatty acids allocate somatic and germline lipids to ensure fitness during nutrient and oxidative stress in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2015; 112:15378-83. [PMID: 26621724 PMCID: PMC4687584 DOI: 10.1073/pnas.1514012112] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Animals in nature are continually challenged by periods of feast and famine as resources inevitably fluctuate, and must allocate somatic reserves for reproduction to abate evolutionary pressures. We identify an age-dependent lipid homeostasis pathway in Caenorhabditis elegans that regulates the mobilization of lipids from the soma to the germline, which supports fecundity but at the cost of survival in nutrient-poor and oxidative stress environments. This trade-off is responsive to the levels of dietary carbohydrates and organismal oleic acid and is coupled to activation of the cytoprotective transcription factor SKN-1 in both laboratory-derived and natural isolates of C. elegans. The homeostatic balance of lipid stores between the somatic and germ cells is mediated by arachidonic acid (omega-6) and eicosapentaenoic acid (omega-3) precursors of eicosanoid signaling molecules. Our results describe a mechanism for resource reallocation within intact animals that influences reproductive fitness at the cost of somatic resilience.
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Affiliation(s)
- Dana A Lynn
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Hans M Dalton
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Jessica N Sowa
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Meng C Wang
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Alexander A Soukas
- Center for Human Genetic Research and Diabetes Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Sean P Curran
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089;
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43
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Dancy BCR, Chen SW, Drechsler R, Gafken PR, Olsen CP. 13C- and 15N-Labeling Strategies Combined with Mass Spectrometry Comprehensively Quantify Phospholipid Dynamics in C. elegans. PLoS One 2015; 10:e0141850. [PMID: 26528916 PMCID: PMC4631354 DOI: 10.1371/journal.pone.0141850] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/13/2015] [Indexed: 01/08/2023] Open
Abstract
Membranes define cellular and organelle boundaries, a function that is critical to all living systems. Like other biomolecules, membrane lipids are dynamically maintained, but current methods are extremely limited for monitoring lipid dynamics in living animals. We developed novel strategies in C. elegans combining 13C and 15N stable isotopes with mass spectrometry to directly quantify the replenishment rates of the individual fatty acids and intact phospholipids of the membrane. Using multiple measurements of phospholipid dynamics, we found that the phospholipid pools are replaced rapidly and at rates nearly double the turnover measured for neutral lipid populations. In fact, our analysis shows that the majority of membrane lipids are replaced each day. Furthermore, we found that stearoyl-CoA desaturases (SCDs), critical enzymes in polyunsaturated fatty acid production, play an unexpected role in influencing the overall rates of membrane maintenance as SCD depletion affected the turnover of nearly all membrane lipids. Additionally, the compromised membrane maintenance as defined by LC-MS/MS with SCD RNAi resulted in active phospholipid remodeling that we predict is critical to alleviate the impact of reduced membrane maintenance in these animals. Not only have these combined methodologies identified new facets of the impact of SCDs on the membrane, but they also have great potential to reveal many undiscovered regulators of phospholipid metabolism.
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Affiliation(s)
- Blair C. R. Dancy
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Shaw-Wen Chen
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Robin Drechsler
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Philip R. Gafken
- Proteomics Facility, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Carissa Perez Olsen
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- * E-mail:
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44
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Lipidomic and proteomic analysis of Caenorhabditis elegans lipid droplets and identification of ACS-4 as a lipid droplet-associated protein. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:1337-45. [PMID: 26121959 DOI: 10.1016/j.bbalip.2015.06.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 06/08/2015] [Accepted: 06/25/2015] [Indexed: 01/08/2023]
Abstract
Lipid droplets are cytoplasmic organelles that store neutral lipids for membrane synthesis and energy reserves. In this study, we characterized the lipid and protein composition of purified Caenorhabditis elegans lipid droplets. These lipid droplets are composed mainly of triacylglycerols, surrounded by a phospholipid monolayer composed primarily of phosphatidylcholine and phosphatidylethanolamine. The fatty acid composition of the triacylglycerols is rich in fatty acid species obtained from the dietary Escherichia coli, including cyclopropane fatty acids and cis-vaccenic acid. Unlike other organisms, C. elegans lipid droplets contain very little cholesterol or cholesterol esters. Comparison of the lipid droplet proteomes of wild type and high-fat daf-2 mutant strains shows a very similar proteome in both strains, except that the most abundant protein in the C. elegans lipid droplet proteome, MDT-28, is relatively less abundant in lipid droplets isolated from daf-2 mutants. Functional analysis of lipid droplet proteins identified in our proteomic studies indicated an enrichment of proteins required for growth and fat homeostasis in C. elegans. Finally, we confirmed the localization of one of the newly identified lipid droplet proteins, ACS-4. We found that ACS-4 localizes to the surface of lipid droplets in the C. elegans intestine and skin. This study bolsters C. elegans as a model to study the dynamics and functions of lipid droplets in a multicellular organism.
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45
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Sheng M, Hosseinzadeh A, Muralidharan SV, Gaur R, Selstam E, Tuck S. Aberrant fat metabolism in Caenorhabditis elegans mutants with defects in the defecation motor program. PLoS One 2015; 10:e0124515. [PMID: 25849533 PMCID: PMC4388766 DOI: 10.1371/journal.pone.0124515] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 03/16/2015] [Indexed: 01/08/2023] Open
Abstract
The molecular mechanisms by which dietary fatty acids are absorbed by the intestine, and the way in which the process is regulated are poorly understood. In a genetic screen for mutations affecting fat accumulation in the intestine of Caenorhabditis elegans, nematode worms, we have isolated mutations in the aex-5 gene, which encodes a Kex2/subtilisin-family, Ca2+-sensitive proprotein convertase known to be required for maturation of certain neuropeptides, and for a discrete step in an ultradian rhythmic phenomenon called the defecation motor program. We demonstrate that aex-5 mutants have markedly lower steady-state levels of fat in the intestine, and that this defect is associated with a significant reduction in the rate at which labeled fatty acid derivatives are taken up from the intestinal lumen. Other mutations affecting the defecation motor program also affect steady-state levels of triglycerides, suggesting that the program is required per se for the proper accumulation of neutral lipids. Our results suggest that an important function of the defecation motor program in C. elegans is to promote the uptake of an important class of dietary nutrients. They also imply that modulation of the program might be one way in which worms adjust nutrient uptake in response to altered metabolic status.
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Affiliation(s)
- Ming Sheng
- Umeå Center for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden
| | - Ava Hosseinzadeh
- Umeå Center for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden
| | | | - Rahul Gaur
- Umeå Center for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden
| | - Eva Selstam
- Department of Plant Physiology, Umeå University, SE-901 87 Umeå, Sweden
| | - Simon Tuck
- Umeå Center for Molecular Medicine, Umeå University, SE-901 87 Umeå, Sweden
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46
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Zhang L, Gualberto DG, Guo X, Correa P, Jee C, Garcia LR. TMC-1 attenuates C. elegans development and sexual behaviour in a chemically defined food environment. Nat Commun 2015; 6:6345. [PMID: 25695879 DOI: 10.1038/ncomms7345] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/21/2015] [Indexed: 01/22/2023] Open
Abstract
Although diet affects growth and behaviour, the adaptive mechanisms that coordinate these processes in non-optimal food sources are unclear. Here we show that the C. elegans tmc-1 channel, which is homologous to the mammalian tmc deafness genes, attenuates development and inhibits sexual behaviour in non-optimal food, the synthetic CeMM medium. In CeMM medium, signalling from the pharyngeal MC neurons and body wall muscles slows larval development. However, in the non-standard diet, mutation in tmc-1 accelerates development, by impairing the excitability of these cells. The tmc-1 larva can immediately generate ATP when fed CeMM, and their fast development requires insulin signalling. Our findings suggest that the tmc-1 channel indirectly affects metabolism in wild-type animals. In addition to regulating the development, we show that mutating tmc-1 can relax diet-induced inhibition of male sexual behaviour, thus indicating that a single regulator can be genetically modified to promote growth rate and reproductive success in new environments.
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Affiliation(s)
- Liusuo Zhang
- Department of Biology, Howard Hughes Medical Institute, Texas A&M University, 3258 TAMU College Station, Texas 77843-3258, USA
| | - Daisy G Gualberto
- Department of Biology, Howard Hughes Medical Institute, Texas A&M University, 3258 TAMU College Station, Texas 77843-3258, USA
| | - Xiaoyan Guo
- Department of Biology, Howard Hughes Medical Institute, Texas A&M University, 3258 TAMU College Station, Texas 77843-3258, USA
| | - Paola Correa
- Department of Biology, Howard Hughes Medical Institute, Texas A&M University, 3258 TAMU College Station, Texas 77843-3258, USA
| | - Changhoon Jee
- Department of Biology, Howard Hughes Medical Institute, Texas A&M University, 3258 TAMU College Station, Texas 77843-3258, USA
| | - L Rene Garcia
- Department of Biology, Howard Hughes Medical Institute, Texas A&M University, 3258 TAMU College Station, Texas 77843-3258, USA
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47
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Khanna A, Johnson DL, Curran SP. Physiological roles for mafr-1 in reproduction and lipid homeostasis. Cell Rep 2014; 9:2180-91. [PMID: 25497095 DOI: 10.1016/j.celrep.2014.11.035] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 11/14/2014] [Accepted: 11/20/2014] [Indexed: 02/02/2023] Open
Abstract
Maf1 is a conserved repressor of RNA polymerase (Pol) III transcription; however, its physiological role in the context of a multicellular organism is not well understood. Here, we show that C. elegans MAFR-1 is functionally orthologous to human Maf1, represses the expression of both RNA Pol III and Pol II transcripts, and mediates organismal fecundity and lipid homeostasis. MAFR-1 impacts lipid transport by modulating intestinal expression of the vitellogenin family of proteins, resulting in cell-nonautonomous defects in the developing reproductive system. MAFR-1 levels inversely correlate with stored intestinal lipids, in part by influencing the expression of the lipogenesis enzymes fasn-1/FASN and pod-2/ACC1. Animals fed a high carbohydrate diet exhibit reduced mafr-1 expression and mutations in the insulin signaling pathway genes daf-18/PTEN and daf-16/FoxO abrogate the lipid storage defects associated with deregulated mafr-1 expression. Our results reveal physiological roles for mafr-1 in regulating organismal lipid homeostasis, which ensure reproductive success.
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Affiliation(s)
- Akshat Khanna
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Deborah L Johnson
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA; Department of Molecular and Computational Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA; Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089, USA.
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48
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daf-31 encodes the catalytic subunit of N alpha-acetyltransferase that regulates Caenorhabditis elegans development, metabolism and adult lifespan. PLoS Genet 2014; 10:e1004699. [PMID: 25330189 PMCID: PMC4199510 DOI: 10.1371/journal.pgen.1004699] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 08/22/2014] [Indexed: 11/19/2022] Open
Abstract
The Caenorhabditis elegans dauer larva is a facultative state of diapause. Mutations affecting dauer signal transduction and morphogenesis have been reported. Of these, most that result in constitutive formation of dauer larvae are temperature-sensitive (ts). The daf-31 mutant was isolated in genetic screens looking for novel and underrepresented classes of mutants that form dauer and dauer-like larvae non-conditionally. Dauer-like larvae are arrested in development and have some, but not all, of the normal dauer characteristics. We show here that daf-31 mutants form dauer-like larvae under starvation conditions but are sensitive to SDS treatment. Moreover, metabolism is shifted to fat accumulation in daf-31 mutants. We cloned the daf-31 gene and it encodes an ortholog of the arrest-defective-1 protein (ARD1) that is the catalytic subunit of the major N alpha-acetyltransferase (NatA). A daf-31 promoter::GFP reporter gene indicates daf-31 is expressed in multiple tissues including neurons, pharynx, intestine and hypodermal cells. Interestingly, overexpression of daf-31 enhances the longevity phenotype of daf-2 mutants, which is dependent on the forkhead transcription factor (FOXO) DAF-16. We demonstrate that overexpression of daf-31 stimulates the transcriptional activity of DAF-16 without influencing its subcellular localization. These data reveal an essential role of NatA in controlling C. elegans life history and also a novel interaction between ARD1 and FOXO transcription factors, which may contribute to understanding the function of ARD1 in mammals. The development of a living organism is influenced by the environmental conditions such as nutrient availability. Under starvation conditions, the C. elegans larvae will enter a special developmental stage called dauer larva. An insulin-like signaling pathway controls dauer formation as well as adult lifespan by inhibiting the activity of FOXO transcription factor DAF-16 that regulates expression of stress-resistant genes. Here we isolate a new gene called daf-31; this gene encodes a protein that regulates C. elegans larval development, metabolism and adult lifespan. This protein has been found in other species to be part of an enzyme that functions to modify other proteins. We show that overexpression of our newly discovered protein stimulates the transcriptional activity of DAF-16. Interestingly, abnormal regulation of human proteins similar to DAF-31 results in tumor formation. It is known that human FOXO proteins prevent tumorigenesis. Therefore, it is possible that abnormal DAF-31 activity may lead to tumor growth by reducing DAF-16 activity. Thus, the present study may not only contribute to understanding the role of a universal enzyme in controlling development, metabolism and lifespan in other organisms besides worms but may also shed light on the mechanisms of tumorigenesis in humans.
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SKN-1 and Nrf2 couples proline catabolism with lipid metabolism during nutrient deprivation. Nat Commun 2014; 5:5048. [PMID: 25284427 PMCID: PMC4205844 DOI: 10.1038/ncomms6048] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 08/20/2014] [Indexed: 02/01/2023] Open
Abstract
Mechanisms that coordinate different metabolic pathways, such as glucose and lipid, have been recognized. However, a potential interaction between amino acid and lipid metabolism remains largely elusive. Here we show that during starvation of Caenorhabditis elegans, proline catabolism is coupled with lipid metabolism by SKN-1. Mutation of alh-6, a conserved proline catabolic enzyme, accelerates fat mobilization, enhances the expression of genes involved in fatty acid oxidation and reduces survival in response to fasting. This metabolic coordination is mediated by the activation of the transcription factor SKN-1/Nrf2, possibly due to the accumulation of the alh-6 substrate P5C, and also requires the transcriptional co-regulator MDT-15. Constitutive activation of SKN-1 induces a similar transcriptional response, which protects animals from fat accumulation when fed a high carbohydrate diet. In human cells, an orthologous alh-6 enzyme, ALDH4A1, is also linked to the activity of Nrf2, the human orthologue of SKN-1, and regulates the expression of lipid metabolic genes. Our findings identify a link between proline catabolism and lipid metabolism, and uncover a physiological role for SKN-1 in metabolism. The coordinated metabolism of cellular nutrients is important to maintain energy homeostasis, particularly if nutrients are scarce. Here, the authors report that the sensor protein SKN-1/Nrf2 links catabolism of the amino acid proline with lipid metabolism in C. elegans and in cultured human cells.
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Storms ZJ, Cameron E, de la Hoz Siegler H, McCaffrey WC. A simple and rapid protocol for measuring neutral lipids in algal cells using fluorescence. J Vis Exp 2014. [PMID: 24961928 DOI: 10.3791/51441] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal fermentation processes and screening for new oil-rich strains requires a fast and reliable protocol for determination of intracellular lipid content. Current practices rely largely on gravimetric methods to determine oil content, techniques developed decades ago that are time consuming and require large sample volumes. In this paper, Nile Red, a fluorescent dye that has been used to identify the presence of lipid bodies in numerous types of organisms, is incorporated into a simple, fast, and reliable protocol for measuring the neutral lipid content of Auxenochlorella protothecoides, a green alga. The method uses ethanol, a relatively mild solvent, to permeabilize the cell membrane before staining and a 96 well micro-plate to increase sample capacity during fluorescence intensity measurements. It has been designed with the specific application of monitoring bioprocess performance. Previously dried samples or live samples from a growing culture can be used in the assay.
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Affiliation(s)
- Zachary J Storms
- Department of Chemical and Materials Engineering, University of Alberta
| | - Elliot Cameron
- Department of Chemical and Materials Engineering, University of Alberta
| | - Hector de la Hoz Siegler
- Department of Chemical and Materials Engineering, University of Alberta; Department of Chemical and Petroleum Engineering, University of Calgary
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