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Martínez BA, Hoyle RG, Yeudall S, Granade ME, Harris TE, Castle JD, Leitinger N, Bland ML. Innate immune signaling in Drosophila shifts anabolic lipid metabolism from triglyceride storage to phospholipid synthesis to support immune function. PLoS Genet 2020; 16:e1009192. [PMID: 33227003 PMCID: PMC7721134 DOI: 10.1371/journal.pgen.1009192] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 12/07/2020] [Accepted: 10/13/2020] [Indexed: 02/07/2023] Open
Abstract
During infection, cellular resources are allocated toward the metabolically-demanding processes of synthesizing and secreting effector proteins that neutralize and kill invading pathogens. In Drosophila, these effectors are antimicrobial peptides (AMPs) that are produced in the fat body, an organ that also serves as a major lipid storage depot. Here we asked how activation of Toll signaling in the larval fat body perturbs lipid homeostasis to understand how cells meet the metabolic demands of the immune response. We find that genetic or physiological activation of fat body Toll signaling leads to a tissue-autonomous reduction in triglyceride storage that is paralleled by decreased transcript levels of the DGAT homolog midway, which carries out the final step of triglyceride synthesis. In contrast, Kennedy pathway enzymes that synthesize membrane phospholipids are induced. Mass spectrometry analysis revealed elevated levels of major phosphatidylcholine and phosphatidylethanolamine species in fat bodies with active Toll signaling. The ER stress mediator Xbp1 contributed to the Toll-dependent induction of Kennedy pathway enzymes, which was blunted by deleting AMP genes, thereby reducing secretory demand elicited by Toll activation. Consistent with ER stress induction, ER volume is expanded in fat body cells with active Toll signaling, as determined by transmission electron microscopy. A major functional consequence of reduced Kennedy pathway induction is an impaired immune response to bacterial infection. Our results establish that Toll signaling induces a shift in anabolic lipid metabolism to favor phospholipid synthesis and ER expansion that may serve the immediate demand for AMP synthesis and secretion but with the long-term consequence of insufficient nutrient storage.
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Affiliation(s)
- Brittany A. Martínez
- Biomedical Sciences Graduate Program, University of Virginia, Charlottesville, VA, United States of America
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States of America
| | - Rosalie G. Hoyle
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States of America
| | - Scott Yeudall
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States of America
- Medical Scientist Training Program, University of Virginia, Charlottesville, VA, United States of America
| | - Mitchell E. Granade
- Biomedical Sciences Graduate Program, University of Virginia, Charlottesville, VA, United States of America
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States of America
| | - Thurl E. Harris
- Biomedical Sciences Graduate Program, University of Virginia, Charlottesville, VA, United States of America
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States of America
| | - J. David Castle
- Department of Cell Biology, University of Virginia, Charlottesville, VA, United States of America
| | - Norbert Leitinger
- Biomedical Sciences Graduate Program, University of Virginia, Charlottesville, VA, United States of America
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States of America
| | - Michelle L. Bland
- Biomedical Sciences Graduate Program, University of Virginia, Charlottesville, VA, United States of America
- Department of Pharmacology, University of Virginia, Charlottesville, VA, United States of America
- * E-mail:
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Reynolds ER. Shortened Lifespan and Other Age-Related Defects in Bang Sensitive Mutants of Drosophila melanogaster. G3 (BETHESDA, MD.) 2018; 8:3953-3960. [PMID: 30355763 PMCID: PMC6288826 DOI: 10.1534/g3.118.200610] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/18/2018] [Indexed: 11/28/2022]
Abstract
Mitochondrial diseases are complex disorders that exhibit their primary effects in energetically active tissues. Damage generated by mitochondria is also thought to be a key component of aging and age-related disease. An important model for mitochondrial dysfunction is the bang sensitive (bs) mutants in Drosophila melanogaster Although these mutants all show a striking seizure phenotype, several bs mutants have gene products that are involved with mitochondrial function, while others affect excitability another way. All of the bs mutants (parabss , eas, jus, ses B, tko are examined here) paralyze and seize upon challenge with a sensory stimulus, most notably mechanical stimulation. These and other excitability mutants have been linked to neurodegeneration with age. In addition to these phenotypes, we have found age-related defects for several of the bs strains. The mutants eas, ses B, and tko display shortened lifespan, an increased mean recovery time from seizure with age, and decreased climbing ability over lifespan as compared to isogenic CS or w1118 lines. Other mutants show a subset of these defects. The age-related phenotypes can be rescued by feeding melatonin, an antioxidant, in all the mutants except ses B The age-related defects do not appear to be correlated with the seizure phenotype. Inducing seizures on a daily basis did not exacerbate the phenotypes and treatment with antiepileptic drugs did not increase lifespan. The results suggest that the excitability phenotypes and the age-related phenotypes may be somewhat independent and that these phenotypes mutants may arise from impacts on different pathways.
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Meltzer S, Bagley JA, Perez GL, O'Brien CE, DeVault L, Guo Y, Jan LY, Jan YN. Phospholipid Homeostasis Regulates Dendrite Morphogenesis in Drosophila Sensory Neurons. Cell Rep 2018; 21:859-866. [PMID: 29069593 DOI: 10.1016/j.celrep.2017.09.089] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2017] [Revised: 08/29/2017] [Accepted: 09/26/2017] [Indexed: 12/01/2022] Open
Abstract
Disruptions in lipid homeostasis have been observed in many neurodevelopmental disorders that are associated with dendrite morphogenesis defects. However, the molecular mechanisms of how lipid homeostasis affects dendrite morphogenesis are unclear. We find that easily shocked (eas), which encodes a kinase with a critical role in phospholipid phosphatidylethanolamine (PE) synthesis, and two other enzymes in this synthesis pathway are required cell autonomously in sensory neurons for dendrite growth and stability. Furthermore, we show that the level of Sterol Regulatory Element-Binding Protein (SREBP) activity is important for dendrite development. SREBP activity increases in eas mutants, and decreasing the level of SREBP and its transcriptional targets in eas mutants largely suppresses the dendrite growth defects. Furthermore, reducing Ca2+ influx in neurons of eas mutants ameliorates the dendrite morphogenesis defects. Our study uncovers a role for EAS kinase and reveals the in vivo function of phospholipid homeostasis in dendrite morphogenesis.
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Affiliation(s)
- Shan Meltzer
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Joshua A Bagley
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Gerardo Lopez Perez
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Caitlin E O'Brien
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Laura DeVault
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Yanmeng Guo
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Lily Yeh Jan
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Yuh-Nung Jan
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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He R, Guo W, Zhang D. An ethanolamine kinase Eki1 affects radial growth and cell wall integrity inTrichoderma reesei. FEMS Microbiol Lett 2015; 362:fnv133. [DOI: 10.1093/femsle/fnv133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2015] [Indexed: 11/13/2022] Open
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Ben-David G, Miller E, Steinhauer J. Drosophila spermatid individualization is sensitive to temperature and fatty acid metabolism. SPERMATOGENESIS 2015; 5:e1006089. [PMID: 26413411 PMCID: PMC4581069 DOI: 10.1080/21565562.2015.1006089] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 12/15/2014] [Accepted: 01/06/2015] [Indexed: 12/18/2022]
Abstract
Fatty acids are precursors of potent lipid signaling molecules. They are stored in membrane phospholipids and released by phospholipase A2 (PLA2). Lysophospholipid acyltransferases (ATs) oppose PLA2 by re-esterifying fatty acids into phospholipids, in a biochemical pathway known as the Lands Cycle. Drosophila Lands Cycle ATs oys and nes, as well as 7 predicted PLA2 genes, are expressed in the male reproductive tract. Oys and Nes are required for spermatid individualization. Individualization, which occurs after terminal differentiation, invests each spermatid in its own plasma membrane and removes the bulk of the cytoplasmic contents. We developed a quantitative assay to measure individualization defects. We demonstrate that individualization is sensitive to temperature and age but not to diet. Mutation of the cyclooxygenase Pxt, which metabolizes fatty acids to prostaglandins, also leads to individualization defects. In contrast, modulating phospholipid levels by mutation of the phosphatidylcholine lipase Swiss cheese (Sws) or the ethanolamine kinase Easily shocked (Eas) does not perturb individualization, nor does Sws overexpression. Our results suggest that fatty acid derived signals such as prostaglandins, whose abundance is regulated by the Lands Cycle, are important regulators of spermatogenesis.
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Affiliation(s)
| | - Eli Miller
- Department of Biology; Yeshiva University ; New York, NY USA
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Lim HY, Wang W, Wessells RJ, Ocorr K, Bodmer R. Phospholipid homeostasis regulates lipid metabolism and cardiac function through SREBP signaling in Drosophila. Genes Dev 2011; 25:189-200. [PMID: 21245170 DOI: 10.1101/gad.1992411] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The epidemic of obesity and diabetes is causing an increased incidence of dyslipidemia-related heart failure. While the primary etiology of lipotoxic cardiomyopathy is an elevation of lipid levels resulting from an imbalance in energy availability and expenditure, increasing evidence suggests a relationship between dysregulation of membrane phospholipid homeostasis and lipid-induced cardiomyopathy. In the present study, we report that the Drosophila easily shocked (eas) mutants that harbor a disturbance in phosphatidylethanolamine (PE) synthesis display tachycardia and defects in cardiac relaxation and are prone to developing cardiac arrest and fibrillation under stress. The eas mutant hearts exhibit elevated concentrations of triglycerides, suggestive of a metabolic, diabetic-like heart phenotype. Moreover, the low PE levels in eas flies mimic the effects of cholesterol deficiency in vertebrates by stimulating the Drosophila sterol regulatory element-binding protein (dSREBP) pathway. Significantly, cardiac-specific elevation of dSREBP signaling adversely affects heart function, reflecting the cardiac eas phenotype, whereas suppressing dSREBP or lipogenic target gene function in eas hearts rescues the cardiac hyperlipidemia and heart function disorders. These findings suggest that dysregulated phospholipid signaling that alters SREBP activity contributes to the progression of impaired heart function in flies and identifies a potential link to lipotoxic cardiac diseases in humans.
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Affiliation(s)
- Hui-Ying Lim
- Development and Aging Program, NASCR (Neuroscience, Aging, and Stem Cell Research) Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, USA
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Kliman M, Vijayakrishnan N, Wang L, Tapp JT, Broadie K, McLean JA. Structural mass spectrometry analysis of lipid changes in a Drosophila epilepsy model brain. MOLECULAR BIOSYSTEMS 2010; 6:958-66. [PMID: 20379606 DOI: 10.1039/b927494d] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphatidylethanolamine (PtdEtn) is one of the most abundant phospholipids in many animal cell types. The Drosophila easily shocked (eas(2)) mutant, used as an epilepsy model, is null for the PtdEtn biosynthetic enzyme, ethanolamine kinase. This mutant displays bang sensitive paralysis, and was previously shown to have decreased levels of PtdEtn. We have developed a highly selective and sensitive measurement strategy using ion mobility-mass spectrometry for the relative quantitation of intact phospholipid species directly from isolated brain tissue of eas mutants. Over 1200 distinct lipid signals are observed and within this population 38, including PtdEtn, phosphatidylinositol (PtdIns) and phosphatidylcholine (PtdCho) species are identified to have changed significantly (p < 0.03) between mutant and control tissue. This method has revealed for the first time the structural complexity and biosynthetic interconnectedness of specific PtdEtn and PtdIns lipid species within tissue, and provides great molecular detail compared to traditionally used detection techniques.
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Affiliation(s)
- Michal Kliman
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Institute of Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
| | - Niranjana Vijayakrishnan
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37235, USA
| | - Lily Wang
- Department of Biostatistics, Vanderbilt University, Nashville, TN 37235, USA
| | - John T Tapp
- Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Kennedy Center, Vanderbilt University, Nashville, TN 37235, USA
| | - John A McLean
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37235, USA.,Vanderbilt Institute of Integrative Biosystems Research and Education, Vanderbilt University, Nashville, TN 37235, USA
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Tian Y, Jackson P, Gunter C, Wang J, Rock CO, Jackowski S. Placental thrombosis and spontaneous fetal death in mice deficient in ethanolamine kinase 2. J Biol Chem 2006; 281:28438-49. [PMID: 16861741 DOI: 10.1074/jbc.m605861200] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ethanolamine kinase catalyzes the first step in the CDP-ethanolamine pathway for the formation of the major membrane phospholipid phosphatidylethanolamine (PtdEtn). In this work, the predicted Etnk2 cDNA was established as a soluble protein with ethanolamine-specific kinase activity that was most highly expressed in liver. Mice with an inactivated Etnk2 gene were derived, and its absence reduced the rate of PtdEtn synthesis from exogenous ethanolamine in hepatocytes. PtdEtn is a major precursor to phosphatidylcholine in liver; however, Etnk2(-/-) mice did not have reduced amounts of either PtdEtn or phosphatidylcholine or an altered phospholipid molecular species distribution. The knock-out animals were able to adapt to a choline-deficient diet. The Etnk2(-/-) mice exhibited a maternal-specific intrauterine growth retardation phenotype that resulted in a 33% reduction in litter size and frequent perinatal death. Histological analysis of pregnant Etnk2(-/-) females showed that fetal development failed at the late stage of pregnancy in a significant percentage of embryos because of the appearance of extensive placental thrombosis. These results illustrate a non-redundant role for EtnK2 expression in regulating placental hemostasis.
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Affiliation(s)
- Yong Tian
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-2794, USA
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Pascual A, Chaminade M, Préat T. Ethanolamine kinase controls neuroblast divisions in Drosophila mushroom bodies. Dev Biol 2005; 280:177-86. [PMID: 15766757 DOI: 10.1016/j.ydbio.2005.01.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 01/07/2005] [Accepted: 01/10/2005] [Indexed: 10/25/2022]
Abstract
The Drosophila mushroom bodies (MBs), paired brain structures composed of vertical and medial lobes, achieve their final organization at metamorphosis. The alpha lobe absent (ala) mutant randomly lacks either the vertical lobes or two of the median lobes. We characterize the ala axonal phenotype at the single-cell level, and show that the ala mutation affects Drosophila ethanolamine (Etn) kinase activity and induces Etn accumulation. Etn kinase is overexpressed in almost all cancer cells. We demonstrate that this enzymatic activity is required in MB neuroblasts to allow a rapid rate of cell division at metamorphosis, linking Etn kinase activity with mitotic progression. Tight control of the pace of neuroblast division is therefore crucial for completion of the developmental program in the adult brain.
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Affiliation(s)
- Alberto Pascual
- Génome, Mémoire et Développement, DEPSN, CNRS, 1 Avenue de la Terrasse, 91190 Gif-sur-Yvette, France
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Reynolds ER, Stauffer EA, Feeney L, Rojahn E, Jacobs B, McKeever C. Treatment with the antiepileptic drugs phenytoin and gabapentin ameliorates seizure and paralysis ofDrosophila bang-sensitive mutants. ACTA ACUST UNITED AC 2004; 58:503-13. [PMID: 14978727 DOI: 10.1002/neu.10297] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Drosophila bang-sensitive (bs) mutants exhibit a stereotypic seizure and paralysis following exposure to mechanical shock. In a physiological preparation, seizures and failures corresponding to the defective behavior are observed in response to high frequency stimulation. The amplitude of the stimulus necessary to produce bs behavior, or seizure threshold, varies with bs mutant and its gene dosage. In many respects, the bs defects are similar to those observed in mammalian seizure disorders. Antiepileptic drugs (AEDs) were administered by feeding to easily shocked(2) (eas(2)), a representative bs mutant. The mean recovery times of treated flies were examined in comparison to control cultures. Some of the drugs administered, including carbamazeprine, ethosuximide, and vigabactrin, had little or no effect on the bs behavior of eas(2). Gabapentin, however, showed a reduction in mean recovery time with chronic drug exposure. Phenytoin also had a significant effect on the bs behavior of treated flies. There was a reduction of both mean recovery time and the percentage of flies that displayed bang-sensitive behavior with both acute and chronic treatment. The adult giant fiber preparation was used to examine the effects of phenytoin physiologically. Treated eas(2) flies showed changes in their response to normal stimulation as well as alterations in seizure threshold in response to high frequency stimulation. Gabapentin was also effective against two other bs mutants, bangsenseless(1) and slamdance(iso7.8), at strain-specific concentrations, while phenytoin also reduced bang-sensitive behaviors in bangsenseless(1) in a dose dependent manner. AEDs, therefore, can be used to dissect aspects of bs behavior and this model may be useful in understanding the underlying basis of seizure disorders.
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Affiliation(s)
- Elaine R Reynolds
- Department of Biology, Lafayette College, Easton, Pennsylvania 18042, USA
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