1
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Luo H, Zhao X, Wang ZD, Wu G, Xia Y, Dong MQ, Ma Y. Sphingolipid profiling reveals differential functions of sphingolipid biosynthesis isozymes of Caenorhabditis elegans. J Lipid Res 2024; 65:100553. [PMID: 38704027 PMCID: PMC11153919 DOI: 10.1016/j.jlr.2024.100553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 04/25/2024] [Accepted: 04/29/2024] [Indexed: 05/06/2024] Open
Abstract
Multiple isozymes are encoded in the Caenorhabditis elegans genome for the various sphingolipid biosynthesis reactions, but the contributions of individual isozymes are characterized only in part. We developed a simple but effective reversed-phase liquid chromatography-tandem mass spectrometry (RPLC-MS/MS) method that enables simultaneous identification and quantification of ceramides (Cer), glucosylceramides (GlcCer), and sphingomyelins (SM) from the same MS run. Validating this sphingolipid profiling method, we show that nearly all 47 quantifiable sphingolipid species found in young adult worms were reduced upon RNA interference (RNAi) of sptl-1 or elo-5, which are both required for synthesis of the id17:1 sphingoid base. We also confirm that HYL-1 and HYL-2, but not LAGR-1, constitute the major ceramide synthase activity with different preference for fatty acid substrates, and that CGT-3, but not CGT-1 and CGT-2, plays a major role in producing GlcCers. Deletion of sms-5 hardly affected SM levels. RNAi of sms-1, sms-2, and sms-3 all lowered the abundance of certain SMs with an odd-numbered N-acyl chains (mostly C21 and C23, with or without hydroxylation). Unexpectedly, sms-2 RNAi and sms-3 RNAi elevated a subset of SM species containing even-numbered N-acyls. This suggests that sphingolipids containing even-numbered N-acyls could be regulated separately, sometimes in opposite directions, from those containing odd-numbered N-acyls, which are presumably monomethyl branched chain fatty acyls. We also find that ceramide levels are kept in balance with those of GlcCers and SMs. These findings underscore the effectiveness of this RPLC-MS/MS method in studies of C. elegans sphingolipid biology.
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Affiliation(s)
- Hui Luo
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; National Institute of Biological Sciences (NIBS), Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China
| | - Xue Zhao
- College of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, China
| | - Zi-Dan Wang
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, China
| | - Gang Wu
- National Institute of Biological Sciences (NIBS), Beijing, China
| | - Yu Xia
- MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing, China.
| | - Meng-Qiu Dong
- Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China; National Institute of Biological Sciences (NIBS), Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
| | - Yan Ma
- National Institute of Biological Sciences (NIBS), Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
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2
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Zhu H, You Y, Yu B, Deng Z, Liu M, Hu Z, Duan J. Loss of the ceramide synthase HYL-2 from Caenorhabditis elegans impairs stress responses and alters sphingolipid composition. J Biol Chem 2024; 300:107320. [PMID: 38677510 PMCID: PMC11145541 DOI: 10.1016/j.jbc.2024.107320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 04/15/2024] [Accepted: 04/16/2024] [Indexed: 04/29/2024] Open
Abstract
Sphingolipids, essential membrane components and signaling molecules in cells, have ceramides at the core of their metabolic pathways. Initially termed as "longevity assurance genes", the encoding genes of ceramide synthases are closely associated with individual aging and stress responses, although the mechanisms remain unclear. This study aims to explore the alterations and underlying mechanisms of three ceramide synthases, HYL-1, HYL-2, and LAGR-1, in the aging and stress responses of Caenorhabditis elegans. Our results showed the knockdown of HYL-1 extends the lifespan and enhance stress resistance in worms, whereas the loss of HYL-2 function significantly impairs tolerances to heat, oxidation, and ultraviolet stress. Stress intolerance induced by HYL-2 deficiency may result from intracellular mitochondrial dysfunction, accumulation of reactive oxygen species, and abnormal nuclear translocation of DAF-16 under stress conditions. Loss of HYL-2 led to a significant reduction of predominant ceramides (d17:1/C20∼C23) as well as corresponding complex sphingolipids. Furthermore, the N-acyl chain length composition of sphingolipids underwent dramatic modifications, characterized by a decrease in C22 sphingolipids and an increase in C24 sphingolipids. Extra d18:1-ceramides resulted in diminished stress resilience in wild-type worms, while supplementation of d18:1/C16 ceramide to HYL-2-deficient worms marginally improved stress tolerance to heat and oxidation. These findings indicate the importance of appropriate ceramide content and composition in maintaining subcellular homeostasis and nuclear-cytoplasmic signal transduction during healthy aging and stress responses.
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Affiliation(s)
- Huaiyi Zhu
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Yunfei You
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Boming Yu
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Zhitao Deng
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Min Liu
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Zhenying Hu
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Jingjing Duan
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, Jiangxi, China.
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3
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Guzman GG, Farley S, Kyle JE, Bramer LM, Hoeltzl S, van den Dikkenberg J, Holthuis JCM, Tafesse FG. Systematic analysis of the sphingomyelin synthase family in C. elegans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.25.550547. [PMID: 37546869 PMCID: PMC10402111 DOI: 10.1101/2023.07.25.550547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Sphingomyelin (SM) is a major component of mammalian cell membranes and particularly abundant in the myelin sheath that surrounds nerve fibers. Its production is catalyzed by SM synthases SMS1 and SMS2, which interconvert phosphatidylcholine and ceramide to diacylglycerol and SM in the Golgi and at the plasma membrane, respectively. As the lipids participating in this reaction fulfill both structural and signaling functions, SMS enzymes have considerable potential to influence diverse important cellular processes. The nematode Caenorhabditis elegans is an attractive model for studying both animal development and human disease. The organism contains five SMS homologues but none of these have been characterized in any detail. Here, we carried out the first systematic analysis of SMS family members in C. elegans . Using heterologous expression systems, genetic ablation, metabolic labeling and lipidome analyses, we show that C. elegans harbors at least three distinct SM synthases and one ceramide phosphoethanolamine (CPE) synthase. Moreover, C. elegans SMS family members have partially overlapping but also unique subcellular distributions and together occupy all principal compartments of the secretory pathway. Our findings shed light on crucial aspects of sphingolipid metabolism in a valuable animal model and opens avenues for exploring the role of SM and its metabolic intermediates in organismal development.
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Çelen İ, Jayasinghe A, Doh JH, Sabanayagam CR. Transcriptomic Signature of the Simulated Microgravity Response in Caenorhabditis elegans and Comparison to Spaceflight Experiments. Cells 2023; 12:270. [PMID: 36672205 PMCID: PMC9856674 DOI: 10.3390/cells12020270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 12/25/2022] [Accepted: 12/28/2022] [Indexed: 01/13/2023] Open
Abstract
Given the growing interest in human exploration of space, it is crucial to identify the effects of space conditions on biological processes. Here, we analyze the transcriptomic response of Caenorhabditis elegans to simulated microgravity and observe the maintained transcriptomic response after returning to ground conditions for four, eight, and twelve days. We show that 75% of the simulated microgravity-induced changes on gene expression persist after returning to ground conditions for four days while most of these changes are reverted after twelve days. Our results from integrative RNA-seq and mass spectrometry analyses suggest that simulated microgravity affects longevity-regulating insulin/IGF-1 and sphingolipid signaling pathways. Finally, we identified 118 genes that are commonly differentially expressed in simulated microgravity- and space-exposed worms. Overall, this work provides insight into the effect of microgravity on biological systems during and after exposure.
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Affiliation(s)
- İrem Çelen
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE 19711, USA
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Aroshan Jayasinghe
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
| | - Jung H. Doh
- Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA
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5
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Lipid metabolism and ageing in Caenorhabditis elegans: a complex interplay. Biogerontology 2022; 23:541-557. [PMID: 36048312 DOI: 10.1007/s10522-022-09989-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 08/25/2022] [Indexed: 11/02/2022]
Abstract
Life expectancy in Western countries is increasing, with concomitant rise in ageing-related pathologies, including Parkinson's and Alzheimer's disease, as well as other neurodegenerative diseases. Consequently, the medical, psychological and economic burden to society is increasing. Thus, understanding the cellular and molecular mechanisms underlying the association of ageing with elevated vulnerability to disease is crucial towards promoting quality of life in old age. Caenorhabditis elegans has emerged as a versatile model to study ageing, due to its simplicity, fast life cycle, and the availability of a wide range of biological tools to target specific genes and cells. Indeed, recent studies in C. elegans have revealed that lipid metabolism plays a key role in controlling longevity by impinging on a plethora of molecular pathways and cell types. Here, we summarise findings relevant to the interplay between lipid metabolism and ageing in C. elegans, and discuss the implications for the pathogenesis of age-related disorders in humans.
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6
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Abstract
Cilium formation and regeneration requires new protein synthesis, but the underlying cytosolic translational reprogramming remains largely unknown. Using ribosome footprinting, we performed global translatome profiling during cilia regeneration in Chlamydomonas and uncovered that flagellar genes undergo an early transcriptional activation but late translational repression. This pattern guided our identification of sphingolipid metabolism enzymes, including serine palmitoyltransferase (SPT), as essential regulators for ciliogenesis. Cryo-electron tomography showed that ceramide loss abnormally increased the membrane-axoneme distance and generated bulged cilia. We found that ceramides interact with intraflagellar transport (IFT) particle proteins that IFT motors transport along axoneme microtubules (MTs), suggesting that ceramide-IFT particle-IFT motor-MT interactions connect the ciliary membrane with the axoneme to form rod-shaped cilia. SPT-deficient vertebrate cells were defective in ciliogenesis, and SPT mutations from patients with hereditary sensory neuropathy disrupted cilia, which could be restored by sphingolipid supplementation. These results reveal a conserved role of sphingolipid in cilium formation and link compromised sphingolipid production with ciliopathies.
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García-Casas P, Alvarez-Illera P, Gómez-Orte E, Cabello J, Fonteriz RI, Montero M, Alvarez J. The Mitochondrial Na +/Ca 2+ Exchanger Inhibitor CGP37157 Preserves Muscle Structure and Function to Increase Lifespan and Healthspan in Caenorhabditis elegans. Front Pharmacol 2021; 12:695687. [PMID: 34211399 PMCID: PMC8241105 DOI: 10.3389/fphar.2021.695687] [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: 04/15/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022] Open
Abstract
We have reported recently that the mitochondrial Na+/Ca2+ exchanger inhibitor CGP37157 extends lifespan in Caenorhabditis elegans by a mechanism involving mitochondria, the TOR pathway and the insulin/IGF1 pathway. Here we show that CGP37157 significantly improved the evolution with age of the sarcomeric regular structure, delaying development of sarcopenia in C. elegans body wall muscle and increasing the average and maximum speed of the worms. Similarly, CGP37157 favored the maintenance of a regular mitochondrial structure during aging. We have also investigated further the mechanism of the effect of CGP37157 by studying its effect in mutants of aak-1;aak-2/AMP-activated kinase, sir-2.1/sirtuin, rsks-1/S6 kinase and daf-16/FOXO. We found that this compound was still effective increasing lifespan in all these mutants, indicating that these pathways are not involved in the effect. We have then monitored pharynx cytosolic and mitochondrial Ca2+ signalling and our results suggest that CGP37157 is probably inhibiting not only the mitochondrial Na+/Ca2+ exchanger, but also Ca2+ entry through the plasma membrane. Finally, a transcriptomic study detected that CGP37157 induced changes in lipid metabolism enzymes and a four-fold increase in the expression of ncx-6, one of the C. elegans mitochondrial Na+/Ca2+ exchangers. In summary, CGP37157 increases both lifespan and healthspan by a mechanism involving changes in cytosolic and mitochondrial Ca2+ homeostasis. Thus, Ca2+ signalling could be a promising target to act on aging.
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Affiliation(s)
- Paloma García-Casas
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
| | - Pilar Alvarez-Illera
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
| | - Eva Gómez-Orte
- Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Juan Cabello
- Center for Biomedical Research of La Rioja (CIBIR), Logroño, Spain
| | - Rosalba I Fonteriz
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
| | - Mayte Montero
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
| | - Javier Alvarez
- Departamento de Bioquímica y Biología Molecular y Fisiología, Facultad de Medicina, Unidad de Excelencia Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and CSIC, Valladolid, Spain
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8
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Bennett HL, McClanahan PD, Fang-Yen C, Kalb RG. Preconditioning of Caenorhabditis elegans to anoxic insult by inactivation of cholinergic, GABAergic and muscle activity. GENES, BRAIN, AND BEHAVIOR 2021; 20:e12713. [PMID: 33155386 DOI: 10.1111/gbb.12713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 10/19/2020] [Accepted: 11/04/2020] [Indexed: 11/26/2022]
Abstract
For most metazoans, oxygen deprivation leads to cell dysfunction and if severe, death. Sublethal stress prior to a hypoxic or anoxic insult ("preconditioning") can protect cells from subsequent oxygen deprivation. The molecular mechanisms by which sublethal stress can buffer against a subsequent toxic insult and the role of the nervous system in the response are not well understood. We studied the role of neuronal activity preconditioning to oxygen deprivation in Caenorhabditis elegans. Animals expressing the histamine gated chloride channels (HisCl1) in select cell populations were used to temporally and spatially inactivate the nervous system or tissue prior to an anoxic insult. We find that inactivation of the nervous system for 3 h prior to the insult confers resistance to a 48-h anoxic insult in 4th-stage larval animals. Experiments show that this resistance can be attributed to loss of activity in cholinergic and GABAergic neurons as well as in body wall muscles. These observations indicate that the nervous system activity can mediate the organism's response to anoxia.
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Affiliation(s)
- Heather L Bennett
- Department of Pediatrics, Division of Neurology, Research Institute, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Biology, Reem-Kayden Center for Science and Computation, Bard College, New York, New York, USA
| | - Patrick D McClanahan
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Christopher Fang-Yen
- Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Robert G Kalb
- Department of Pediatrics, Division of Neurology, Research Institute, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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9
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Baugh LR, Hu PJ. Starvation Responses Throughout the Caenorhabditiselegans Life Cycle. Genetics 2020; 216:837-878. [PMID: 33268389 PMCID: PMC7768255 DOI: 10.1534/genetics.120.303565] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/17/2020] [Indexed: 02/07/2023] Open
Abstract
Caenorhabditis elegans survives on ephemeral food sources in the wild, and the species has a variety of adaptive responses to starvation. These features of its life history make the worm a powerful model for studying developmental, behavioral, and metabolic starvation responses. Starvation resistance is fundamental to life in the wild, and it is relevant to aging and common diseases such as cancer and diabetes. Worms respond to acute starvation at different times in the life cycle by arresting development and altering gene expression and metabolism. They also anticipate starvation during early larval development, engaging an alternative developmental program resulting in dauer diapause. By arresting development, these responses postpone growth and reproduction until feeding resumes. A common set of signaling pathways mediates systemic regulation of development in each context but with important distinctions. Several aspects of behavior, including feeding, foraging, taxis, egg laying, sleep, and associative learning, are also affected by starvation. A variety of conserved signaling, gene regulatory, and metabolic mechanisms support adaptation to starvation. Early life starvation can have persistent effects on adults and their descendants. With its short generation time, C. elegans is an ideal model for studying maternal provisioning, transgenerational epigenetic inheritance, and developmental origins of adult health and disease in humans. This review provides a comprehensive overview of starvation responses throughout the C. elegans life cycle.
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Affiliation(s)
- L Ryan Baugh
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina 27708 and
| | - Patrick J Hu
- Departments of Medicine and Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
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10
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Qu Z, Ji S, Zheng S. Glucose and cholesterol induce abnormal cell divisions via DAF-12 and MPK-1 in C. elegans. Aging (Albany NY) 2020; 12:16255-16269. [PMID: 32857726 PMCID: PMC7485695 DOI: 10.18632/aging.103647] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 06/19/2020] [Indexed: 12/26/2022]
Abstract
People exposed to starvation have a high risk of developing cancer later in life, and prior studies have shown these individuals have high insulin and cholesterol levels and are sensitive to glucose. Using C. elegans as a model, we found that glucose and cholesterol can promote survival and cause starved L1 diapause worms to undergo abnormal neuronal cell divisions. Starvation has also been shown to promote long-term survival; however, we found that the functions of glucose and cholesterol in relation to these cell divisions are distinct from their effects on survival. We demonstrate that glucose functions in a DAF-16/FOXO-independent IIS pathway to activate the MAPK ontogenetic signaling to induce neuronal Q-cell divisions, and cholesterol works through DAF-12/steroidogenic pathways to promote these cell divisions. daf-12 and mpk-1/MAPK mutants suppress the function of glucose and cholesterol in these divisions, and a fully functioning dpMPK-1 requires the steroid hormone receptor DAF-12 for these divisions to occur. These afflictions also can be passed on to the immediate progeny. This work indicates a possible link between glucose and cholesterol in starved animals and an increased risk of cancer.
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Affiliation(s)
- Zhi Qu
- School of Nursing and Health, Henan University, Kaifeng 475004, Henan Province, China.,Medical School, Henan University, Kaifeng 475004, Henan Province, China
| | - Shaoping Ji
- School of Basic Medical Sciences, Henan University, Kaifeng 475004, Henan Province, China.,Medical School, Henan University, Kaifeng 475004, Henan Province, China
| | - Shanqing Zheng
- School of Basic Medical Sciences, Henan University, Kaifeng 475004, Henan Province, China.,Medical School, Henan University, Kaifeng 475004, Henan Province, China
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11
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Reduced Serum Sphingolipids Constitute a Molecular Signature of Malnutrition in Hospitalized Patients With Decompensated Cirrhosis. Clin Transl Gastroenterol 2020; 10:e00013. [PMID: 30908309 PMCID: PMC6445606 DOI: 10.14309/ctg.0000000000000013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Malnutrition is a leading cause of morbidity and mortality in cirrhosis. Although multiple noninvasive measures of nutritional status have been studied, no consensus exists for early identification of malnutrition in cirrhosis. Serum metabolomics offers a novel approach for identifying biomarkers in multiple disease states. To characterize alterations in metabolic pathways associated with malnutrition in hospitalized cirrhotic patients and to identify biomarkers for disease prognosis.
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12
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Duong T, Rasmussen NR, Ballato E, Mote FS, Reiner DJ. The Rheb-TORC1 signaling axis functions as a developmental checkpoint. Development 2020; 147:dev.181727. [PMID: 32041790 DOI: 10.1242/dev.181727] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 01/22/2020] [Indexed: 12/12/2022]
Abstract
In many eukaryotes, the small GTPase Rheb functions as a switch to toggle activity of TOR complex 1 (TORC1) between anabolism and catabolism, thus controlling lifespan, development and autophagy. Our CRISPR-generated, fluorescently tagged endogenous Caenorhabditis elegans RHEB-1 and DAF-15/Raptor are expressed ubiquitously and localize to lysosomes. LET-363/TOR and DAF-15/Raptor are required for development beyond the third larval stage (L3). We observed that deletion of RHEB-1 similarly conferred L3 arrest. Unexpectedly, robust RNAi-mediated depletion of TORC1 components caused arrest at stages prior to L3. Accordingly, conditional depletion of endogenous DAF-15/Raptor in the soma revealed that TORC1 is required at each stage of the life cycle to progress to the next stage. Reversal of DAF-15 depletion permits arrested animals to recover to continue development. Our results are consistent with TORC1 functioning as a developmental checkpoint that governs the decision of the animal to progress through development.
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Affiliation(s)
- Tam Duong
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - Neal R Rasmussen
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - Elliot Ballato
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - F Sefakor Mote
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
| | - David J Reiner
- Center for Translational Cancer Research, Institute of Biosciences and Technology, Texas A&M Health Science Center, Texas A&M University, Houston, TX 77030, USA
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13
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Cheng X, Jiang X, Tam KY, Li G, Zheng J, Zhang H. Sphingolipidomic Analysis of C. elegans reveals Development- and Environment-dependent Metabolic Features. Int J Biol Sci 2019; 15:2897-2910. [PMID: 31853226 PMCID: PMC6909964 DOI: 10.7150/ijbs.30499] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 10/02/2019] [Indexed: 01/12/2023] Open
Abstract
Sphingolipids (SLs) serve as structural and signaling molecules in regulating various cellular events and growth. Given that SLs contain various bioactive species possessing distinct roles, quantitative analysis of sphingolipidome is essential for elucidating their differential requirement during development. Herein we developed a comprehensive sphingolipidomic profiling approach using liquid chromatography-mass spectrometry coupled with multiple reaction monitoring mode (LC-MS-MRM). SL profiling of C. elegans revealed organism-specific, development-dependent and environment-driven metabolic features. We showed for the first time the presence of a series of sphingoid bases in C. elegans sphingolipid profiles, although only C17-sphingoid base is used for generating complex SLs. Moreover, we successfully resolved growth-, temperature- and nutrition-dependent SL profiles at both individual metabolite-level and network-level. Sphingolipidomic analysis uncovered significant SL composition changes throughout development, with SMs/GluCers ratios dramatically increasing from larva to adult stage whereas total sphingolipid levels exhibiting opposing trends. We also identified a temperature-dependent alteration in SMs/GluCers ratios, suggesting an organism-specific strategy for environmental adaptation. Finally, we found serine-biased GluCer increases between serine- versus alanine-supplemented worms. Our study builds a “reference” resource for future SL analysis in the worm, provides insights into natural variability and plasticity of eukaryotic multicellular sphingolipid composition and is highly valuable for investigating their functional significance.
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Affiliation(s)
- Xiaoxiang Cheng
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Xue Jiang
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Kin Yip Tam
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Gang Li
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Jun Zheng
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China
| | - Hongjie Zhang
- Faculty of Health Sciences, University of Macau, Taipa, Macau SAR 999078, China.,Centre of Reproduction, Development and Ageing, University of Macau, Taipa, Macau SAR 999078, China
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14
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Sphingosine kinase and p38 MAP kinase signaling promote resistance to arsenite-induced lethality in Caenorhabditis elegan. Mol Cell Toxicol 2019. [DOI: 10.1007/s13273-019-0045-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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15
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Blackwell TK, Sewell AK, Wu Z, Han M. TOR Signaling in Caenorhabditis elegans Development, Metabolism, and Aging. Genetics 2019; 213:329-360. [PMID: 31594908 PMCID: PMC6781902 DOI: 10.1534/genetics.119.302504] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 07/18/2019] [Indexed: 12/30/2022] Open
Abstract
The Target of Rapamycin (TOR or mTOR) is a serine/threonine kinase that regulates growth, development, and behaviors by modulating protein synthesis, autophagy, and multiple other cellular processes in response to changes in nutrients and other cues. Over recent years, TOR has been studied intensively in mammalian cell culture and genetic systems because of its importance in growth, metabolism, cancer, and aging. Through its advantages for unbiased, and high-throughput, genetic and in vivo studies, Caenorhabditis elegans has made major contributions to our understanding of TOR biology. Genetic analyses in the worm have revealed unexpected aspects of TOR functions and regulation, and have the potential to further expand our understanding of how growth and metabolic regulation influence development. In the aging field, C. elegans has played a leading role in revealing the promise of TOR inhibition as a strategy for extending life span, and identifying mechanisms that function upstream and downstream of TOR to influence aging. Here, we review the state of the TOR field in C. elegans, and focus on what we have learned about its functions in development, metabolism, and aging. We discuss knowledge gaps, including the potential pitfalls in translating findings back and forth across organisms, but also describe how TOR is important for C. elegans biology, and how C. elegans work has developed paradigms of great importance for the broader TOR field.
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Affiliation(s)
- T Keith Blackwell
- Research Division, Joslin Diabetes Center, Department of Genetics, Harvard Medical School, Harvard Stem Cell Institute, Boston, Massachusetts
| | - Aileen K Sewell
- Department of MCDB, University of Colorado at Boulder, and
- Howard Hughes Medical Institute, Boulder, Colorado
| | - Ziyun Wu
- Research Division, Joslin Diabetes Center, Department of Genetics, Harvard Medical School, Harvard Stem Cell Institute, Boston, Massachusetts
| | - Min Han
- Department of MCDB, University of Colorado at Boulder, and
- Howard Hughes Medical Institute, Boulder, Colorado
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Abstract
Ceramides are sphingolipids containing a sphingosine or a related base, to which a fatty acid is linked through an amide bond. When incorporated into a lipid bilayer, ceramides exhibit a number of properties not shared by almost any other membrane lipid: Ceramides ( a) are extremely hydrophobic and thus cannot exist in suspension in aqueous media; ( b) increase the molecular order (rigidity) of phospholipids in membranes; ( c) give rise to lateral phase separation and domain formation in phospholipid bilayers; ( d) possess a marked intrinsic negative curvature that facilitates formation of inverted hexagonal phases; ( e) make bilayers and cell membranes permeable to small and large (i.e., protein-size) solutes; and ( f) promote transmembrane (flip-flop) lipid motion. Unfortunately, there is hardly any link between the physical studies reviewed here and the mass of biological and clinical studies on the effects of ceramides in health and disease.
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Affiliation(s)
- Alicia Alonso
- Instituto Biofisika [University of the Basque Country and Spanish National Research Council (CSIC)], 48940 Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain;,
| | - Félix M. Goñi
- Instituto Biofisika [University of the Basque Country and Spanish National Research Council (CSIC)], 48940 Leioa, Spain
- Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa, Spain;,
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17
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Abstract
This review provides an overview on components of the sphingolipid superfamily, on their localization and metabolism. Information about the sphingolipid biological activity in cell physiopathology is given. Recent studies highlight the role of sphingolipids in inflammatory process. We summarize the emerging data that support the different roles of the sphingolipid members in specific phases of inflammation: (1) migration of immune cells, (2) recognition of exogenous agents, and (3) activation/differentiation of immune cells.
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18
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Chan JP, Brown J, Hark B, Nolan A, Servello D, Hrobuchak H, Staab TA. Loss of Sphingosine Kinase Alters Life History Traits and Locomotor Function in Caenorhabditis elegans. Front Genet 2017; 8:132. [PMID: 28983319 PMCID: PMC5613162 DOI: 10.3389/fgene.2017.00132] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 09/06/2017] [Indexed: 12/15/2022] Open
Abstract
Sphingolipid metabolism is important to balance the abundance of bioactive lipid molecules involved in cell signaling, neuronal function, and survival. Specifically, the sphingolipid sphingosine mediates cell death signaling, whereas its phosphorylated form, sphingosine-1-phosphate (S1P), mediates cell survival signaling. The enzyme sphingosine kinase produces S1P, and the activity of sphingosine kinase impacts the ability of cells to survive under stress and challenges. To examine the influence of sphingolipid metabolism, particularly enzymes regulating sphingosine and S1P, in mediating aging, neuronal function and stress response, we examined life history traits, locomotor capacities and heat stress responses of young and old animals using the model organism Caenorhabditis elegans. We found that C. elegans sphk-1 mutants, which lack sphingosine kinase, had shorter lifespans, reduced brood sizes, and smaller body sizes compared to wild type animals. By analyzing a panel of young and old animals with genetic mutations in the sphingolipid signaling pathway, we showed that aged sphk-1 mutants exhibited a greater decline in neuromuscular function and locomotor behavior. In addition, aged animals lacking sphk-1 were more susceptible to death induced by acute and prolonged heat exposure. On the other hand, older animals with loss of function mutations in ceramide synthase (hyl-1), which converts sphingosine to ceramide, showed improved neuromuscular function and stress response with age. This phenotype was dependent on sphk-1. Together, our data show that loss of sphingosine kinase contributes to poor animal health span, suggesting that sphingolipid signaling may be important for healthy neuronal function and animal stress response during aging.
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Affiliation(s)
- Jason P Chan
- Department of Biology, Juniata CollegeHuntingdon, PA, United States
| | - Jaylene Brown
- Department of Biology, Juniata CollegeHuntingdon, PA, United States
| | - Brandon Hark
- Department of Biology, Juniata CollegeHuntingdon, PA, United States
| | - Abby Nolan
- Department of Biology, Juniata CollegeHuntingdon, PA, United States
| | - Dustin Servello
- Department of Biology, Juniata CollegeHuntingdon, PA, United States
| | - Hannah Hrobuchak
- Department of Biology, Juniata CollegeHuntingdon, PA, United States
| | - Trisha A Staab
- Department of Biology, Juniata CollegeHuntingdon, PA, United States
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