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Perouansky M, Johnson-Schlitz D, Sedensky MM, Morgan PG. A primordial target: Mitochondria mediate both primary and collateral anesthetic effects of volatile anesthetics. Exp Biol Med (Maywood) 2023; 248:545-552. [PMID: 37208922 PMCID: PMC10350799 DOI: 10.1177/15353702231165025] [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] [Indexed: 05/21/2023] Open
Abstract
One of the unsolved mysteries of medicine is how do volatile anesthetics (VAs) cause a patient to reversibly lose consciousness. In addition, identifying mechanisms for the collateral effects of VAs, including anesthetic-induced neurotoxicity (AiN) and anesthetic preconditioning (AP), has proven challenging. Multiple classes of molecules (lipids, proteins, and water) have been considered as potential VA targets, but recently proteins have received the most attention. Studies targeting neuronal receptors or ion channels had limited success in identifying the critical targets of VAs mediating either the phenotype of "anesthesia" or their collateral effects. Recent studies in both nematodes and fruit flies may provide a paradigm shift by suggesting that mitochondria may harbor the upstream molecular switch activating both primary and collateral effects. The disruption of a specific step of electron transfer within the mitochondrion causes hypersensitivity to VAs, from nematodes to Drosophila and to humans, while also modulating the sensitivity to collateral effects. The downstream effects from mitochondrial inhibition are potentially legion, but inhibition of presynaptic neurotransmitter cycling appears to be specifically sensitive to the mitochondrial effects. These findings are perhaps of even broader interest since two recent reports indicate that mitochondrial damage may well underlie neurotoxic and neuroprotective effects of VAs in the central nervous system (CNS). It is, therefore, important to understand how anesthetics interact with mitochondria to affect CNS function, not just for the desired facets of general anesthesia but also for significant collateral effects, both harmful and beneficial. A tantalizing possibility exists that both the primary (anesthesia) and secondary (AiN, AP) mechanisms may at least partially overlap in the mitochondrial electron transport chain (ETC).
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Affiliation(s)
- Misha Perouansky
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
- Laboratory of Genetics, School of Medicine and Public Health and College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Dena Johnson-Schlitz
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Margaret M Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA 98101, USA
| | - Philip G Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA 98101, USA
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2
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Pupal size as a proxy for fat content in laboratory-reared and field-collected Drosophila species. Sci Rep 2022; 12:12855. [PMID: 35896578 PMCID: PMC9329298 DOI: 10.1038/s41598-022-15325-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/22/2022] [Indexed: 11/09/2022] Open
Abstract
In arthropods, larger individuals tend to have more fat reserves, but data for many taxa are still missing. For the vinegar fly Drosophila melanogaster, only few studies have provided experimental data linking body size to fat content. This is rather surprising considering the widespread use of D. melanogaster as a model system in biology. Here, we hypothesized that fat content in D. melanogaster is positively correlated with body size. To test this, we manipulated the developmental environment of D. melanogaster by decreasing food availability. We then measured pupal size and quantified fat content of laboratory-reared D. melanogaster. We subsequently measured pupal size and fat content of several field-caught Drosophila species. Starvation, crowding, and reduced nutrient content led to smaller laboratory-reared pupae that contained less fat. Pupal size was indeed found to be positively correlated with fat content. The same correlation was found for field-caught Drosophila pupae belonging to different species. As fat reserves are often strongly linked to fitness in insects, further knowledge on the relationship between body size and fat content can provide important information for studies on insect ecology and physiology.
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3
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Johnson-Schlitz D, Fischer JA, Schiffman HJ, Scharenbrock AR, Olufs ZPG, Wassarman DA, Perouansky M. Anesthetic Preconditioning of Traumatic Brain Injury Is Ineffective in a Drosophila Model of Obesity. J Pharmacol Exp Ther 2022; 381:229-235. [PMID: 35347062 PMCID: PMC9190232 DOI: 10.1124/jpet.121.000997] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 03/21/2022] [Indexed: 07/09/2024] Open
Abstract
We tested the hypothesis that obesity influences the pharmacodynamics of volatile general anesthetics (VGAs) by comparing effects of anesthetic exposure on mortality from traumatic brain injury (TBI) in lean and obese Drosophila melanogaster We induced TBI with a high-impact trauma device. Starvation-selection over multiple generations resulted in an obese phenotype (SS flies). Fed flies served as lean controls (FC flies). Adult (1-8-day-old) SS and FC flies were exposed to equianesthetic doses of isoflurane or sevoflurane either before or after TBI. The principal outcome was percent mortality 24 hours after injury, expressed as the Mortality Index at 24 hours (MI24). TBI resulted in a lower MI24 in FC than in SS flies [21 (2.35) and 57.8 (2.14), respectively n = 12, P = 0.0001]. Pre-exposure to isoflurane or sevoflurane preconditioned FC flies to TBI, reducing the risk of death to 0.53 (0.25 to 1.13) and 0.82 (0.43 to 1.58), respectively, but had no preconditioning effect in SS flies. Postexposure to isoflurane or sevoflurane increased the risk of death in SS flies, but only postexposure to isoflurane increased the risk in FC flies [1.39 (0.81 to 2.38)]. Thus, obesity affects the pharmacodynamics of VGAs, thwarting the preconditioning effect of isoflurane and sevoflurane in TBI. SIGNIFICANCE STATEMENT: Inadvertent preconditioning in models of traumatic brain injury (TBI) is a recognized confounder. The findings in a fruit fly (Drosophila melanogaster) model of closed-head TBI indicate that anesthetic pharmacodynamics are profoundly affected by obesity. Specifically, obesity thwarts the brain-protective effect of anesthetic preconditioning. This finding is important for experimental studies of TBI and supports the versatility of the fruit fly as a model for the exploration of anesthetic pharmacodynamics in a wide parameter space.
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Affiliation(s)
- Dena Johnson-Schlitz
- Department of Anesthesiology (D.J.-S., J.A.F., H.J.S., A.R.S., Z.P.G.O., M.P.) and Department of Medical Genetics (D.A.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Julie A Fischer
- Department of Anesthesiology (D.J.-S., J.A.F., H.J.S., A.R.S., Z.P.G.O., M.P.) and Department of Medical Genetics (D.A.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Hannah J Schiffman
- Department of Anesthesiology (D.J.-S., J.A.F., H.J.S., A.R.S., Z.P.G.O., M.P.) and Department of Medical Genetics (D.A.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Amanda R Scharenbrock
- Department of Anesthesiology (D.J.-S., J.A.F., H.J.S., A.R.S., Z.P.G.O., M.P.) and Department of Medical Genetics (D.A.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Zachariah P G Olufs
- Department of Anesthesiology (D.J.-S., J.A.F., H.J.S., A.R.S., Z.P.G.O., M.P.) and Department of Medical Genetics (D.A.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - David A Wassarman
- Department of Anesthesiology (D.J.-S., J.A.F., H.J.S., A.R.S., Z.P.G.O., M.P.) and Department of Medical Genetics (D.A.W.), University of Wisconsin-Madison, Madison, Wisconsin
| | - Misha Perouansky
- Department of Anesthesiology (D.J.-S., J.A.F., H.J.S., A.R.S., Z.P.G.O., M.P.) and Department of Medical Genetics (D.A.W.), University of Wisconsin-Madison, Madison, Wisconsin
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4
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Phenotyping of Drosophila melanogaster—A Nutritional Perspective. Biomolecules 2022; 12:biom12020221. [PMID: 35204721 PMCID: PMC8961528 DOI: 10.3390/biom12020221] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/15/2022] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
The model organism Drosophila melanogaster was increasingly applied in nutrition research in recent years. A range of methods are available for the phenotyping of D. melanogaster, which are outlined in the first part of this review. The methods include determinations of body weight, body composition, food intake, lifespan, locomotor activity, reproductive capacity and stress tolerance. In the second part, the practical application of the phenotyping of flies is demonstrated via a discussion of obese phenotypes in response to high-sugar diet (HSD) and high-fat diet (HFD) feeding. HSD feeding and HFD feeding are dietary interventions that lead to an increase in fat storage and affect carbohydrate-insulin homeostasis, lifespan, locomotor activity, reproductive capacity and stress tolerance. Furthermore, studies regarding the impacts of HSD and HFD on the transcriptome and metabolome of D. melanogaster are important for relating phenotypic changes to underlying molecular mechanisms. Overall, D. melanogaster was demonstrated to be a valuable model organism with which to examine the pathogeneses and underlying molecular mechanisms of common chronic metabolic diseases in a nutritional context.
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Tuthill II BF, Quaglia CJ, O'Hara E, Musselman LP. Loss of Stearoyl-CoA desaturase 1 leads to cardiac dysfunction and lipotoxicity. J Exp Biol 2021; 224:jeb240432. [PMID: 34423827 PMCID: PMC8502255 DOI: 10.1242/jeb.240432] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 08/16/2021] [Indexed: 12/28/2022]
Abstract
Diets high in carbohydrates are associated with type 2 diabetes and its co-morbidities, including hyperglycemia, hyperlipidemia, obesity, hepatic steatosis and cardiovascular disease. We used a high-sugar diet to study the pathophysiology of diet-induced metabolic disease in Drosophila melanogaster. High-sugar diets produce hyperglycemia, obesity, insulin resistance and cardiomyopathy in flies, along with ectopic accumulation of toxic lipids, or lipotoxicity. Stearoyl-CoA desaturase 1 is an enzyme that contributes to long-chain fatty acid metabolism by introducing a double bond into the acyl chain. Knockdown of stearoyl-CoA desaturase 1 in the fat body reduced lipogenesis and exacerbated pathophysiology in flies reared on high-sucrose diets. These flies exhibited dyslipidemia and growth deficiency in addition to defects in cardiac and gut function. We assessed the lipidome of these flies using tandem mass spectrometry to provide insight into the relationship between potentially lipotoxic species and type 2 diabetes-like pathophysiology. Oleic acid supplementation is able to rescue a variety of phenotypes produced by stearoyl-CoA desaturase 1 RNAi, including fly mass, triglyceride storage, gut development and cardiac failure. Taken together, these data suggest a protective role for monounsaturated fatty acids in diet-induced metabolic disease phenotypes.
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6
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Hillyer JF, Pass G. The Insect Circulatory System: Structure, Function, and Evolution. ANNUAL REVIEW OF ENTOMOLOGY 2020; 65:121-143. [PMID: 31585504 DOI: 10.1146/annurev-ento-011019-025003] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Although the insect circulatory system is involved in a multitude of vital physiological processes, it has gone grossly understudied. This review highlights this critical physiological system by detailing the structure and function of the circulatory organs, including the dorsal heart and the accessory pulsatile organs that supply hemolymph to the appendages. It also emphasizes how the circulatory system develops and ages and how, by means of reflex bleeding and functional integration with the immune system, it supports mechanisms for defense against predators and microbial invaders, respectively. Beyond that, this review details evolutionary trends and novelties associated with this system, as well as the ways in which this system also plays critical roles in thermoregulation and tracheal ventilation in high-performance fliers. Finally, this review highlights how novel discoveries could be harnessed for the control of vector-borne diseases and for translational medicine, and it details principal knowledge gaps that necessitate further investigation.
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Affiliation(s)
- Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37235, USA;
| | - Günther Pass
- Department of Integrative Zoology, University of Vienna, 1090 Vienna, Austria;
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7
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Wen DT, Zheng L, Li JX, Cheng D, Liu Y, Lu K, Hou WQ. Endurance exercise resistance to lipotoxic cardiomyopathy is associated with cardiac NAD +/dSIR2/ PGC-1α pathway activation in old Drosophila. Biol Open 2019; 8:bio044719. [PMID: 31624074 PMCID: PMC6826281 DOI: 10.1242/bio.044719] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/23/2019] [Indexed: 12/17/2022] Open
Abstract
Lipotoxic cardiomyopathy is caused by excessive lipid accumulation in myocardial cells and it is a form of cardiac dysfunction. Cardiac PGC-1α overexpression prevents lipotoxic cardiomyopathy induced by a high-fat diet (HFD). The level of NAD+ and Sir2 expression upregulate the transcriptional activity of PGC-1α. Exercise improves cardiac NAD+ level and PGC-1α activity. However, the relationship between exercise, NAD+/dSIR2/PGC-1α pathway and lipotoxic cardiomyopathy remains unknown. In this study, flies were fed a HFD and exercised. The heart dSir2 gene was specifically expressed or knocked down by UAS/hand-Gal4 system. The results showed that either a HFD or dSir2 knockdown remarkably increased cardiac TG level and d FAS expression, reduced heart fractional shortening and diastolic diameter, increased arrhythmia index, and decreased heart NAD+ level, dSIR2 protein, dSir2 and PGC-1α expression levels. Contrarily, either exercise or dSir2 overexpression remarkably reduced heart TG level, dFAS expression and arrhythmia index, and notably increased heart fractional shortening, diastolic diameter, NAD+ level, dSIR2 level, and heart dSir2 and PGC-1α expression. Therefore, we declared that exercise training could improve lipotoxic cardiomyopathy induced by a HFD or cardiac dSir2 knockdown in old Drosophila The NAD+/dSIR2/PGC-1α pathway activation was an important molecular mechanism of exercise resistance against lipotoxic cardiomyopathy.
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Affiliation(s)
- Deng-Tai Wen
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410012, Hunan Province, China
- Department of Sports Science, Ludong University, Yantai 264025, Shandong Province, China
| | - Lan Zheng
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410012, Hunan Province, China
| | - Jin-Xiu Li
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410012, Hunan Province, China
| | - Dan Cheng
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410012, Hunan Province, China
| | - Yang Liu
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410012, Hunan Province, China
| | - Kai Lu
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410012, Hunan Province, China
| | - Wen-Qi Hou
- Key Laboratory of Physical Fitness and Exercise Rehabilitation of Hunan Province, Hunan Normal University, Changsha 410012, Hunan Province, China
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8
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Everman ER, McNeil CL, Hackett JL, Bain CL, Macdonald SJ. Dissection of Complex, Fitness-Related Traits in Multiple Drosophila Mapping Populations Offers Insight into the Genetic Control of Stress Resistance. Genetics 2019; 211:1449-1467. [PMID: 30760490 PMCID: PMC6456312 DOI: 10.1534/genetics.119.301930] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Accepted: 02/06/2019] [Indexed: 12/11/2022] Open
Abstract
We leverage two complementary Drosophila melanogaster mapping panels to genetically dissect starvation resistance-an important fitness trait. Using >1600 genotypes from the multiparental Drosophila Synthetic Population Resource (DSPR), we map numerous starvation stress QTL that collectively explain a substantial fraction of trait heritability. Mapped QTL effects allowed us to estimate DSPR founder phenotypes, predictions that were correlated with the actual phenotypes of these lines. We observe a modest phenotypic correlation between starvation resistance and triglyceride level, traits that have been linked in previous studies. However, overlap among QTL identified for each trait is low. Since we also show that DSPR strains with extreme starvation phenotypes differ in desiccation resistance and activity level, our data imply multiple physiological mechanisms contribute to starvation variability. We additionally exploited the Drosophila Genetic Reference Panel (DGRP) to identify sequence variants associated with starvation resistance. Consistent with prior work these sites rarely fall within QTL intervals mapped in the DSPR. We were offered a unique opportunity to directly compare association mapping results across laboratories since two other groups previously measured starvation resistance in the DGRP. We found strong phenotypic correlations among studies, but extremely low overlap in the sets of genomewide significant sites. Despite this, our analyses revealed that the most highly associated variants from each study typically showed the same additive effect sign in independent studies, in contrast to otherwise equivalent sets of random variants. This consistency provides evidence for reproducible trait-associated sites in a widely used mapping panel, and highlights the polygenic nature of starvation resistance.
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Affiliation(s)
- Elizabeth R Everman
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045
| | - Casey L McNeil
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045
| | - Jennifer L Hackett
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045
| | - Clint L Bain
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045
| | - Stuart J Macdonald
- Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045
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9
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Hardy CM, Burke MK, Everett LJ, Han MV, Lantz KM, Gibbs AG. Genome-Wide Analysis of Starvation-Selected Drosophila melanogaster-A Genetic Model of Obesity. Mol Biol Evol 2019; 35:50-65. [PMID: 29309688 DOI: 10.1093/molbev/msx254] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Experimental evolution affords the opportunity to investigate adaptation to stressful environments. Studies combining experimental evolution with whole-genome resequencing have provided insight into the dynamics of adaptation and a new tool to uncover genes associated with polygenic traits. Here, we selected for starvation resistance in populations of Drosophila melanogaster for over 80 generations. In response, the starvation-selected lines developed an obese condition, storing nearly twice the level of total lipids than their unselected controls. Although these fats provide a ∼3-fold increase in starvation resistance, the imbalance in lipid homeostasis incurs evolutionary cost. Some of these tradeoffs resemble obesity-associated pathologies in mammals including metabolic depression, low activity levels, dilated cardiomyopathy, and disrupted sleeping patterns. To determine the genetic basis of these traits, we resequenced genomic DNA from the selected lines and their controls. We found 1,046,373 polymorphic sites, many of which diverged between selection treatments. In addition, we found a wide range of genetic heterogeneity between the replicates of the selected lines, suggesting multiple mechanisms of adaptation. Genome-wide heterozygosity was low in the selected populations, with many large blocks of SNPs nearing fixation. We found candidate loci under selection by using an algorithm to control for the effects of genetic drift. These loci were mapped to a set of 382 genes, which associated with many processes including nutrient response, catabolic metabolism, and lipid droplet function. The results of our study speak to the evolutionary origins of obesity and provide new targets to understand the polygenic nature of obesity in a unique model system.
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Affiliation(s)
- Christopher M Hardy
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV.,Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV
| | - Molly K Burke
- Department of Integrative Biology, Oregon State University, Corvallis, OR
| | - Logan J Everett
- Department of Biological Sciences, North Carolina State University, Raleigh, NC
| | - Mira V Han
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV.,Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV
| | - Kathryn M Lantz
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV.,Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV
| | - Allen G Gibbs
- School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV.,Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, Las Vegas, NV
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Age- and Genotype-Specific Effects of the Angiotensin-Converting Enzyme Inhibitor Lisinopril on Mitochondrial and Metabolic Parameters in Drosophila melanogaster. Int J Mol Sci 2018; 19:ijms19113351. [PMID: 30373167 PMCID: PMC6274988 DOI: 10.3390/ijms19113351] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Revised: 10/18/2018] [Accepted: 10/24/2018] [Indexed: 12/18/2022] Open
Abstract
The angiotensin-converting enzyme (ACE) is a peptidase that is involved in the synthesis of Angiotensin II, the bioactive component of the renin-angiotensin system. A growing body of literature argues for a beneficial impact of ACE inhibitors (ACEi) on age-associated metabolic disorders, mediated by cellular changes in reactive oxygen species (ROS) that improve mitochondrial function. Yet, our understanding of the relationship between ACEi therapy and metabolic parameters is limited. Here, we used three genetically diverse strains of Drosophila melanogaster to show that Lisinopril treatment reduces thoracic ROS levels and mitochondrial respiration in young flies, and increases mitochondrial content in middle-aged flies. Using untargeted metabolomics analysis, we also showed that Lisinopril perturbs the thoracic metabolic network structure by affecting metabolic pathways involved in glycogen degradation, glycolysis, and mevalonate metabolism. The Lisinopril-induced effects on mitochondrial and metabolic parameters, however, are genotype-specific and likely reflect the drug's impact on nutrient-dependent fitness traits. Accordingly, we found that Lisinopril negatively affects survival under nutrient starvation, an effect that can be blunted by genotype and age in a manner that partially mirrors the drug-induced changes in mitochondrial respiration. In conclusion, our results provide novel and important insights into the role of ACEi in cellular metabolism.
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11
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Male courtship behaviors and female choice reduced during experimental starvation stress. Behav Ecol 2018. [DOI: 10.1093/beheco/ary144] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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12
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Bacterial Methionine Metabolism Genes Influence Drosophila melanogaster Starvation Resistance. Appl Environ Microbiol 2018; 84:AEM.00662-18. [PMID: 29934334 DOI: 10.1128/aem.00662-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/25/2018] [Indexed: 11/20/2022] Open
Abstract
Animal-associated microorganisms (microbiota) dramatically influence the nutritional and physiological traits of their hosts. To expand our understanding of such influences, we predicted bacterial genes that influence a quantitative animal trait by a comparative genomic approach, and we extended these predictions via mutant analysis. We focused on Drosophila melanogaster starvation resistance (SR). We first confirmed that D. melanogaster SR responds to the microbiota by demonstrating that bacterium-free flies have greater SR than flies bearing a standard 5-species microbial community, and we extended this analysis by revealing the species-specific influences of 38 genome-sequenced bacterial species on D. melanogaster SR. A subsequent metagenome-wide association analysis predicted bacterial genes with potential influence on D. melanogaster SR, among which were significant enrichments in bacterial genes for the metabolism of sulfur-containing amino acids and B vitamins. Dietary supplementation experiments established that the addition of methionine, but not B vitamins, to the diets significantly lowered D. melanogaster SR in a way that was additive, but not interactive, with the microbiota. A direct role for bacterial methionine metabolism genes in D. melanogaster SR was subsequently confirmed by analysis of flies that were reared individually with distinct methionine cycle Escherichia coli mutants. The correlated responses of D. melanogaster SR to bacterial methionine metabolism mutants and dietary modification are consistent with the established finding that bacteria can influence fly phenotypes through dietary modification, although we do not provide explicit evidence of this conclusion. Taken together, this work reveals that D. melanogaster SR is a microbiota-responsive trait, and specific bacterial genes underlie these influences.IMPORTANCE Extending descriptive studies of animal-associated microorganisms (microbiota) to define causal mechanistic bases for their influence on animal traits is an emerging imperative. In this study, we reveal that D. melanogaster starvation resistance (SR), a model quantitative trait in animal genetics, responds to the presence and identity of the microbiota. Using a predictive analysis, we reveal that the amino acid methionine has a key influence on D. melanogaster SR and show that bacterial methionine metabolism mutants alter normal patterns of SR in flies bearing the bacteria. Our data further suggest that these effects are additive, and we propose the untested hypothesis that, similar to bacterial effects on fruit fly triacylglyceride deposition, the bacterial influence may be through dietary modification. Together, these findings expand our understanding of the bacterial genetic basis for influence on a nutritionally relevant trait of a model animal host.
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Abstract
Excess adipose fat accumulation, or obesity, is a growing problem worldwide in terms of both the rate of incidence and the severity of obesity-associated metabolic disease. Adipose tissue evolved in animals as a specialized dynamic lipid storage depot: adipose cells synthesize fat (a process called lipogenesis) when energy is plentiful and mobilize stored fat (a process called lipolysis) when energy is needed. When a disruption of lipid homeostasis favors increased fat synthesis and storage with little turnover owing to genetic predisposition, overnutrition or sedentary living, complications such as diabetes and cardiovascular disease are more likely to arise. The vinegar fly Drosophila melanogaster (Diptera: Drosophilidae) is used as a model to better understand the mechanisms governing fat metabolism and distribution. Flies offer a wealth of paradigms with which to study the regulation and physiological effects of fat accumulation. Obese flies accumulate triacylglycerols in the fat body, an organ similar to mammalian adipose tissue, which specializes in lipid storage and catabolism. Discoveries in Drosophila have ranged from endocrine hormones that control obesity to subcellular mechanisms that regulate lipogenesis and lipolysis, many of which are evolutionarily conserved. Furthermore, obese flies exhibit pathophysiological complications, including hyperglycemia, reduced longevity and cardiovascular function - similar to those observed in obese humans. Here, we review some of the salient features of the fly that enable researchers to study the contributions of feeding, absorption, distribution and the metabolism of lipids to systemic physiology.
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Affiliation(s)
- Laura Palanker Musselman
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, NY 13902, USA
| | - Ronald P Kühnlein
- Department of Biochemistry 1, Institute of Molecular Biosciences, University of Graz, Humboldtstraβe 50/II, A-8010 Graz, Austria.,BioTechMed-Graz, Graz, Austria
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14
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Brookheart RT, Duncan JG. Modeling dietary influences on offspring metabolic programming in Drosophila melanogaster. Reproduction 2017; 152:R79-90. [PMID: 27450801 DOI: 10.1530/rep-15-0595] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 05/17/2016] [Indexed: 01/08/2023]
Abstract
The influence of nutrition on offspring metabolism has become a hot topic in recent years owing to the growing prevalence of maternal and childhood obesity. Studies in mammals have identified several factors correlating with parental and early offspring dietary influences on progeny health; however, the molecular mechanisms that underlie these factors remain undiscovered. Mammalian metabolic tissues and pathways are heavily conserved in Drosophila melanogaster, making the fly an invaluable genetic model organism for studying metabolism. In this review, we discuss the metabolic similarities between mammals and Drosophila and present evidence supporting its use as an emerging model of metabolic programming.
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Affiliation(s)
- Rita T Brookheart
- Department of PediatricsWashington University School of Medicine, St Louis, MO, USA
| | - Jennifer G Duncan
- Department of PediatricsWashington University School of Medicine, St Louis, MO, USA
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15
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Doran CR, Estévez-Lao TY, Hillyer JF. Mosquito aging modulates the heart rate and the proportional directionality of heart contractions. JOURNAL OF INSECT PHYSIOLOGY 2017; 101:47-56. [PMID: 28655496 DOI: 10.1016/j.jinsphys.2017.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/12/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
Mosquito aging impacts a myriad of physiological processes, including digestion, flight, mating, reproductive success, and immunity. In the present study, we conducted intravital video imaging in 1, 3, 5, 10, 15 and 20-day-old Anopheles gambiae female adults to assess whether aging impacts mosquito heart physiology. We found that the heart contraction rate increases over the first 15days of adulthood and then decreases. These changes occur for both contraction directions, although aging results in a relative change in the anterograde versus retrograde contraction rates. That is, whereas for the first 5days of life the anterograde and retrograde contraction rates are similar, from day 10 to day 20 the retrograde contraction rate is higher than the anterograde contraction rate. Aging also biases the proportional directionality of heart contractions, from approximately two thirds of the time being spent contracting in the anterograde direction and two thirds of the contractions propagating anterograde during the first 5days of life to an approximately even split between anterograde and retrograde when the mosquitoes have reached 10 to 20days of age. Transcriptional analyses of crustacean cardioactive peptide (CCAP), FMRFamide, calcium-calmodulin dependent kinase II (CaMKII), pygopus, manganese-iron superoxide dismutase (MnSOD1) and vinculin by quantitative RT-PCR revealed age-associated changes in gene expression, with MnSOD1 and vinculin expression showing a declining trend with age. RNAi-based knockdown of MnSOD1 or vinculin resulted in heart physiology that trended toward the aging phenotype for every parameter that was measured, suggesting that these two genes are involved in cardiac aging.
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Affiliation(s)
- Charlotte R Doran
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Tania Y Estévez-Lao
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Julián F Hillyer
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA.
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16
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Kezos JN, Cabral LG, Wong BD, Khou BK, Oh A, Harb JF, Chiem D, Bradley TJ, Mueller LD, Rose MR. Starvation but not locomotion enhances heart robustness in Drosophila. JOURNAL OF INSECT PHYSIOLOGY 2017; 99:8-14. [PMID: 28285040 DOI: 10.1016/j.jinsphys.2017.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 02/27/2017] [Accepted: 03/06/2017] [Indexed: 06/06/2023]
Abstract
Insects and vertebrates have multiple major physiological systems, each species having a circulatory system, a metabolic system, and a respiratory system that enable locomotion and survival in stressful environments, among other functions. Broadening our understanding of the physiology of Drosophila melanogaster requires the parsing of interrelationships among such major component physiological systems. By combining electrical pacing and flight exhaustion assays with manipulative conditioning, we have started to unpack the interrelationships between cardiac function, locomotor performance, and other functional characters such as starvation and desiccation resistance. Manipulative sequences incorporating these four physiological characters were applied to five D. melanogaster lab populations that share a common origin from the wild and a common history of experimental evolution. While exposure to starvation or desiccation significantly reduced flight duration, exhaustion due to flight only affected subsequent desiccation resistance. A strong association was found between flight duration and desiccation resistance, providing additional support for the hypothesis that these traits depend on glycogen and water content. However, there was negligible impact on rate of cardiac arrests from exhaustion by flight or exposure to desiccant. Brief periods of starvation significantly lowered the rate of cardiac arrest. These results provide suggestive support for the adverse impact of lipids on Drosophila heart robustness, a parallel result to those of many comparable studies in human cardiology. Overall, this study underscores clear distinctions among the connections between specific physiological responses to stress and specific types of physiological performance.
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Affiliation(s)
- James N Kezos
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Larry G Cabral
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Brandon D Wong
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Belinda K Khou
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Angela Oh
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Jerry F Harb
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Danny Chiem
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Timothy J Bradley
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Laurence D Mueller
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
| | - Michael R Rose
- Department of Ecology and Evolutionary Biology, Francisco J. Ayala School of Biological Sciences, University of California, Irvine, CA 92697-2525, United States.
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17
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Burggren W, Souder BM, Ho DH. Metabolic rate and hypoxia tolerance are affected by group interactions and sex in the fruit fly ( Drosophila melanogaster): new data and a literature survey. Biol Open 2017; 6:471-480. [PMID: 28202465 PMCID: PMC5399560 DOI: 10.1242/bio.023994] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Population density and associated behavioral adjustments are potentially important in regulating physiological performance in many animals. In r-selected species like the fruit fly (Drosophila), where population density rapidly shifts in unpredictable and unstable environments, density-dependent physiological adjustments may aid survival of individuals living in a social environment. Yet, how population density (and associated social behaviors) affects physiological functions like metabolism is poorly understood in insects. Additionally, insects often show marked sexual dimorphism (larger females). Thus, in this study on D. melanogaster, we characterized the effects of fly density and sex on both mass-specific routine oxygen consumption (V̇O2) and hypoxia tolerance (PCrit). Females had significantly lower routine V̇O2 (∼4 µl O2 mg−1 h−1) than males (∼6 µl O2 mg−1 h−1) at an average fly density of 28 flies·respirometer chamber−1. However, V̇O2 was inversely related to fly density in males, with V̇O2 ranging from 4 to 11 µl O2 mg−1 h−1 at a density of 10 and 40 flies·chamber−1, respectively (r2=0.58, P<0.001). Female flies showed a similar but less pronounced effect, with a V̇O2 of 4 and 7 µl O2 mg−1 h−1 at a density of 10 and 40 flies·chamber−1, respectively (r2=0.43, P<0.001). PCrit (∼5.5 to 7.5 kPa) varied significantly with density in male (r2=0.50, P<0.01) but not female (r2=0.02, P>0.5) flies, with higher fly densities having a lower PCrit. An extensive survey of the literature on metabolism in fruit flies indicates that not all studies control for, or even report on, fly density and gender, both of which may affect metabolic measurements. Summary: Technical advances allowing oxygen consumption measurement in individual fruit flies actually take them out of their normal highly social context, resulting in higher oxygen consumption rates than in natural groups.
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Affiliation(s)
- Warren Burggren
- Developmental Integrative Biology Group, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
| | - BriAnna M Souder
- Developmental Integrative Biology Group, Department of Biological Sciences, University of North Texas, Denton, TX 76203, USA
| | - Dao H Ho
- Department of Clinical Investigation, Tripler Army Medical Center, Honolulu, HI 96859, USA
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18
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Shahrestani P, Burke MK, Birse R, Kezos JN, Ocorr K, Mueller LD, Rose MR, Bodmer R. Experimental Evolution and Heart Function in Drosophila. Physiol Biochem Zool 2017; 90:281-293. [PMID: 28277957 DOI: 10.1086/689288] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Drosophila melanogaster is a good model species for the study of heart function. However, most previous work on D. melanogaster heart function has focused on the effects of large-effect genetic variants. We compare heart function among 18 D. melanogaster populations that have been selected for altered development time, aging, or stress resistance. We find that populations with faster development and faster aging have increased heart dysfunction, measured as percentage heart failure after electrical pacing. Experimental evolution of different triglyceride levels, by contrast, has little effect on heart function. Evolved differences in heart function correlate with allele frequency changes at many loci of small effect. Genomic analysis of these populations produces a list of candidate loci that might affect cardiac function at the intersection of development, aging, and metabolic control mechanisms.
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19
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Obesity-Related Diseases and Syndromes: Insulin Resistance, Type 2 Diabetes Mellitus, Non-alcoholic Fatty Liver Disease, Cardiovascular Disease, and Metabolic Syndrome. Obesity (Silver Spring) 2016. [DOI: 10.1007/978-3-319-39409-1_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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