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Wang 王宇扬 Y, Little AG, Aristizabal MJ, Robertson RM. Low Glycolysis Is Neuroprotective during Anoxic Spreading Depolarization (SD) and Reoxygenation in Locusts. eNeuro 2023; 10:ENEURO.0325-23.2023. [PMID: 37932046 PMCID: PMC10683553 DOI: 10.1523/eneuro.0325-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 10/24/2023] [Accepted: 10/31/2023] [Indexed: 11/08/2023] Open
Abstract
Migratory locusts enter a reversible hypometabolic coma to survive environmental anoxia, wherein the cessation of CNS activity is driven by spreading depolarization (SD). While glycolysis is recognized as a crucial anaerobic energy source contributing to animal anoxia tolerance, its influence on the anoxic SD trajectory and recovery outcomes remains poorly understood. We investigated the effects of varying glycolytic capacity on adult female locust anoxic SD parameters, using glucose or the glycolytic inhibitors 2-deoxy-d-glucose (2DG) or monosodium iodoacetate (MIA). Surprisingly, 2DG treatment shared similarities with glucose yet had opposite effects compared with MIA. Specifically, although SD onset was not affected, both glucose and 2DG expedited the recovery of CNS electrical activity during reoxygenation, whereas MIA delayed it. Additionally, glucose and MIA, but not 2DG, increased tissue damage and neural cell death following anoxia-reoxygenation. Notably, glucose-induced injuries were associated with heightened CO2 output during the early phase of reoxygenation. Conversely, 2DG resulted in a bimodal response, initially dampening CO2 output and gradually increasing it throughout the recovery period. Given the discrepancies between effects of 2DG and MIA, the current results require cautious interpretations. Nonetheless, our findings present evidence that glycolysis is not a critical metabolic component in either anoxic SD onset or recovery and that heightened glycolysis during reoxygenation may exacerbate CNS injuries. Furthermore, we suggest that locust anoxic recovery is not solely dependent on energy availability, and the regulation of metabolic flux during early reoxygenation may constitute a strategy to mitigate damage.
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Affiliation(s)
- Yuyang Wang 王宇扬
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | | | - Maria J Aristizabal
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - R Meldrum Robertson
- Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada
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2
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Zhang K, Tuo Y, Liu R, Yan H, Xiang P, Wang Z, Huang P. The use of untargeted and widely targeted metabolomics to distinguish between asphyxia and sudden cardiac death as the cause of death in rats: A preliminary study. ARAB J CHEM 2022. [DOI: 10.1016/j.arabjc.2022.104322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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3
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Qiu S, Xiao C, Robertson RM. Knockdown of a Cyclic Nucleotide-Gated Ion Channel Impairs Locomotor Activity and Recovery From Hypoxia in Adult Drosophila melanogaster. Front Physiol 2022; 13:852919. [PMID: 35530504 PMCID: PMC9075734 DOI: 10.3389/fphys.2022.852919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 03/02/2022] [Indexed: 11/13/2022] Open
Abstract
Cyclic guanosine monophosphate (cGMP) modulates the speed of recovery from anoxia in adult Drosophila and mediates hypoxia-related behaviors in larvae. Cyclic nucleotide-gated channels (CNG) and cGMP-activated protein kinase (PKG) are two cGMP downstream targets. PKG is involved in behavioral tolerance to hypoxia and anoxia in adults, however little is known about a role for CNG channels. We used a CNGL (CNG-like) mutant with reduced CNGL transcripts to investigate the contribution of CNGL to the hypoxia response. CNGL mutants had reduced locomotor activity under normoxia. A shorter distance travelled in a standard locomotor assay was due to a slower walking speed and more frequent stops. In control flies, hypoxia immediately reduced path length per minute. Flies took 30–40 min in normoxia for >90% recovery of path length per minute from 15 min hypoxia. CNGL mutants had impaired recovery from hypoxia; 40 min for ∼10% recovery of walking speed. The effects of CNGL mutation on locomotor activity and recovery from hypoxia were recapitulated by pan-neuronal CNGL knockdown. Genetic manipulation to increase cGMP in the CNGL mutants increased locomotor activity under normoxia and eliminated the impairment of recovery from hypoxia. We conclude that CNGL channels and cGMP signaling are involved in the control of locomotor activity and the hypoxic response of adult Drosophila.
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Affiliation(s)
- Shuang Qiu
- Department of Biology, Queen's University, Kingston, ON, Canada
| | - Chengfeng Xiao
- Department of Biology, Queen's University, Kingston, ON, Canada
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4
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Srithiphaphirom P, Robertson RM. Rapid cold hardening delays the onset of anoxia-induced coma via an octopaminergic pathway in Locusta migratoria. JOURNAL OF INSECT PHYSIOLOGY 2022; 137:104360. [PMID: 35041846 DOI: 10.1016/j.jinsphys.2022.104360] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/05/2022] [Accepted: 01/12/2022] [Indexed: 06/14/2023]
Abstract
Rapid cold hardening (RCH) is a short-term hormesis that occurs in many invertebrate species, especially in insects. Although RCH is best known as enhancing cold tolerance, it can also enhance anoxic tolerance. When exposed to prolonged anoxia, insects enter a reversible coma, which is associated with spreading depolarization (SD) in the central nervous system (CNS). In this study, we investigated the effects of RCH and octopamine (OA) on anoxia-induced SD in L. migratoria. OA is an insect stress hormone that has roles in many physiological processes. Thus, we hypothesized that OA is involved in the mechanism of RCH. First, we found that RCH affects the K+ sensitivity of the locust blood brain barrier (BBB) in a way similar to the previously described effects of OA. Next, using SD as an indicator of anoxia-induced coma, we took a pharmacological approach to investigate the effects of OA and epinastine (EP), an octopaminergic receptor (OctR) antagonist. We found that OA mimics, whereas EP blocks, the effect of RCH on anoxia-induced SD. This study demonstrates that OA is involved in the mechanism of RCH in delaying the onset of anoxia-induced locust coma and contributes to determining the mechanism of RCH that modulates insect stress tolerances.
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5
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Dason JS, Anreiter I, Wu CF. Transcending boundaries: from quantitative genetics to single genes. J Neurogenet 2021; 35:95-98. [PMID: 34544325 DOI: 10.1080/01677063.2021.1960519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Jeffrey S Dason
- Department of Biomedical Sciences, University of Windsor, Windsor, Canada
| | - Ina Anreiter
- Department of Neurobiology, Stanford University, Stanford, CA, USA
| | - Chun-Fang Wu
- Department of Biology, University of Iowa, Iowa City, IA, USA
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6
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Allen AM, B Sokolowski M. Expression of the foraging gene in adult Drosophila melanogaster. J Neurogenet 2021; 35:192-212. [PMID: 34382904 PMCID: PMC8846931 DOI: 10.1080/01677063.2021.1941946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The foraging gene in Drosophila melanogaster, which encodes a cGMP-dependent protein kinase, is a highly conserved, complex gene with multiple pleiotropic behavioral and physiological functions in both the larval and adult fly. Adult foraging expression is less well characterized than in the larva. We characterized foraging expression in the brain, gastric system, and reproductive systems using a T2A-Gal4 gene-trap allele. In the brain, foraging expression appears to be restricted to multiple sub-types of glia. This glial-specific cellular localization of foraging was supported by single-cell transcriptomic atlases of the adult brain. foraging is extensively expressed in most cell types in the gastric and reproductive systems. We then mapped multiple cis-regulatory elements responsible for parts of the observed expression patterns by a nested cloned promoter-Gal4 analysis. The mapped cis-regulatory elements were consistently modular when comparing the larval and adult expression patterns. These new data using the T2A-Gal4 gene-trap and cloned foraging promoter fusion GAL4's are discussed with respect to previous work using an anti-FOR antibody, which we show here to be non-specific. Future studies of foraging's function will consider roles for glial subtypes and peripheral tissues (gastric and reproductive systems) in foraging's pleiotropic behavioral and physiological effects.
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Affiliation(s)
- Aaron M Allen
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Centre for Neural Circuits and Behaviour, University of Oxford, Oxford, UK
| | - Marla B Sokolowski
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Canada
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7
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Krill JL, Dawson-Scully K. Characterization of a novel stimulus-induced glial calcium wave in Drosophila larval peripheral segmental nerves and its role in PKG-modulated thermoprotection. J Neurogenet 2021; 35:221-235. [PMID: 34309496 DOI: 10.1080/01677063.2021.1941945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Insects, as poikilotherms, have adaptations to deal with wide ranges in temperature fluctuation. Allelic variations in the foraging gene that encodes a cGMP dependent protein kinase, were discovered to have effects on behavior in Drosophila by Dr. Marla Sokolowski in 1980. This single gene has many pleiotropic effects and influences feeding behavior, metabolic storage, learning and memory and has been shown to affect stress tolerance. PKG regulation affects motoneuronal thermotolerance in Drosophila larvae as well as adults. While the focus of thermotolerance studies has been on the modulation of neuronal function, other cell types have been overlooked. Because glia are vital to neuronal function and survival, we wanted to determine if glia play a role in thermotolerance as well. In our investigation, we discovered a novel calcium wave at the larval NMJ and set out to characterize the wave's dynamics and the potential mechanism underlying the wave prior to determining what effect, if any, PKG modulation has on the thermotolerance of glia cells. Using pharmacology, we determined that calcium buffering mechanisms of the mitochondria and endoplasmic reticulum play a role in the propagation of our novel glial calcium wave. By coupling pharmacology with genetic manipulation using RNA interference (RNAi), we found that PKG modulation in glia alters thermoprotection of function as well as glial calcium wave dynamics.
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Affiliation(s)
- Jennifer L Krill
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida
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8
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The Foraging Gene, a New Environmental Adaptation Player Involved in Xenobiotic Detoxification. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18147508. [PMID: 34299961 PMCID: PMC8305630 DOI: 10.3390/ijerph18147508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 11/16/2022]
Abstract
Foraging is vital for animals, especially for food. In Drosophila melanogaster, this behavior is controlled by the foraging gene (for) which encodes a cyclic guanosine monophosphate (cGMP)-dependent protein kinase (PKG). In wild populations of Drosophila, rover individuals that exhibit long foraging trails and sitter individuals that exhibit short ones coexist and are characterized by high and low levels of PKG activity, respectively. We, therefore, postulated that rover flies are more exposed to environmental stresses, including xenobiotics contamination, than sitter flies. We then tested whether these flies differed in their ability to cope with xenobiotics by exposing them to insecticides from different chemical families. We performed toxicological tests and measured the activity and expression levels of different classes of detoxification enzymes. We have shown that a link exists between the for gene and certain cytochrome P450-dependent activities and that the expression of the insecticide-metabolizing cytochrome P450 Cyp6a2 is controlled by the for gene. An unsuspected regulatory pathway of P450s expression involving the for gene in Drosophila is revealed and we demonstrate its involvement in adaptation to chemicals in the environment. This work can serve as a basis for reconsidering adaptation to xenobiotics in light of the behavior of species, including humans.
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Alwash N, Allen AM, B Sokolowski M, Levine JD. The Drosophila melanogaster foraging gene affects social networks. J Neurogenet 2021; 35:249-261. [PMID: 34121597 DOI: 10.1080/01677063.2021.1936517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Drosophila melanogaster displays social behaviors including courtship, mating, aggression, and group foraging. Recent studies employed social network analyses (SNAs) to show that D. melanogaster strains differ in their group behavior, suggesting that genes influence social network phenotypes. Aside from genes associated with sensory function, few studies address the genetic underpinnings of these networks. The foraging gene (for) is a well-established example of a pleiotropic gene that regulates multiple behavioral phenotypes and their plasticity. In D. melanogaster, there are two naturally occurring alleles of for called rover and sitter that differ in their larval and adult food-search behavior as well as other behavioral phenotypes. Here, we hypothesize that for affects behavioral elements required to form social networks and the social networks themselves. These effects are evident when we manipulate gene dosage. We found that flies of the rover and sitter strains exhibit differences in duration, frequency, and reciprocity of pairwise interactions, and they form social networks with differences in assortativity and global efficiency. Consistent with other adult phenotypes influenced by for, rover-sitter heterozygotes show intermediate patterns of dominance in many of these characteristics. Multiple generations of backcrossing a rover allele into a sitter strain showed that many but not all of these rover-sitter differences may be attributed to allelic variation at for. Our findings reveal the significant role that for plays in affecting social network properties and their behavioral elements in Drosophila melanogaster.
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Affiliation(s)
- Nawar Alwash
- Department of Biology, University of Toronto at Mississauga, Mississauga, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Aaron M Allen
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Centre for Neural Circuits and Behavior, University of Oxford, Oxford, UK
| | - Marla B Sokolowski
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), MaRS Centre, Toronto, Canada
| | - Joel D Levine
- Department of Biology, University of Toronto at Mississauga, Mississauga, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), MaRS Centre, Toronto, Canada
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10
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Oepen AS, Catalano JL, Azanchi R, Kaun KR. The foraging gene affects alcohol sensitivity, metabolism and memory in Drosophila. J Neurogenet 2021; 35:236-248. [PMID: 34092172 DOI: 10.1080/01677063.2021.1931178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The genetic basis of alcohol use disorder (AUD) is complex. Understanding how natural genetic variation contributes to alcohol phenotypes can help us identify and understand the genetic basis of AUD. Recently, a single nucleotide polymorphism in the human foraging (for) gene ortholog, Protein Kinase cGMP-Dependent 1 (PRKG1), was found to be associated with stress-induced risk for alcohol abuse. However, the mechanistic role that PRKG1 plays in AUD is not well understood. We use natural variation in the Drosophila for gene to describe how variation of cGMP-dependent protein kinase (PKG) activity modifies ethanol-induced phenotypes. We found that variation in for affects ethanol-induced increases in locomotion and memory of the appetitive properties of ethanol intoxication. Further, these differences may stem from the ability to metabolize ethanol. Together, this data suggests that natural variation in PKG modulates cue reactivity for alcohol, and thus could influence alcohol cravings by differentially modulating metabolic and behavioral sensitivities to alcohol.
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Affiliation(s)
- Anne S Oepen
- Department of Neuroscience, Brown University, Providence, RI, USA.,Masters Program in Developmental, Neuronal and Behavioral Biology, Georg-August-University, Göttingen, Germany
| | - Jamie L Catalano
- Department of Neuroscience, Brown University, Providence, RI, USA.,Molecular Pharmacology and Physiology Graduate Program, Brown University, Providence, RI, USA
| | - Reza Azanchi
- Department of Neuroscience, Brown University, Providence, RI, USA
| | - Karla R Kaun
- Department of Neuroscience, Brown University, Providence, RI, USA
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11
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Dason JS, Sokolowski MB. A cGMP-dependent protein kinase, encoded by the Drosophila foraging gene, regulates neurotransmission through changes in synaptic structure and function. J Neurogenet 2021; 35:213-220. [PMID: 33998378 DOI: 10.1080/01677063.2021.1905639] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
A cGMP-dependent protein kinase (PKG) encoded by the Drosophila foraging (for) gene regulates both synaptic structure (nerve terminal growth) and function (neurotransmission) through independent mechanisms at the Drosophila larval neuromuscular junction (nmj). Glial for is known to restrict nerve terminal growth, whereas presynaptic for inhibits synaptic vesicle (SV) exocytosis during low frequency stimulation. Presynaptic for also facilitates SV endocytosis during high frequency stimulation. for's effects on neurotransmission can occur independent of any changes in nerve terminal growth. However, it remains unclear if for's effects on neurotransmission affect nerve terminal growth. Furthermore, it's possible that for's effects on synaptic structure contribute to changes in neurotransmission. In the present study, we examined these questions using RNA interference to selectively knockdown for in presynaptic neurons or glia at the Drosophila larval nmj. Consistent with our previous findings, presynaptic knockdown of for impaired SV endocytosis, whereas knockdown of glial for had no effect on SV endocytosis. Surprisingly, we found that knockdown of either presynaptic or glial for increased neurotransmitter release in response to low frequency stimulation. Knockdown of presynaptic for did not affect nerve terminal growth, demonstrating that for's effects on neurotransmission does not alter nerve terminal growth. In contrast, knockdown of glial for enhanced nerve terminal growth. This enhanced nerve terminal growth was likely the cause of the enhanced neurotransmitter release seen following knockdown of glial for. Overall, we show that for can affect neurotransmitter release by regulating both synaptic structure and function.
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Affiliation(s)
- Jeffrey S Dason
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada.,Department of Biomedical Sciences, University of Windsor, Windsor, Canada
| | - Marla B Sokolowski
- Department of Cell & Systems Biology, University of Toronto, Toronto, Canada.,Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Canada.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Canada
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12
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Robertson RM, Dawson-Scully KD, Andrew RD. Neural shutdown under stress: an evolutionary perspective on spreading depolarization. J Neurophysiol 2020; 123:885-895. [PMID: 32023142 PMCID: PMC7099469 DOI: 10.1152/jn.00724.2019] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/13/2020] [Accepted: 01/14/2020] [Indexed: 11/22/2022] Open
Abstract
Neural function depends on maintaining cellular membrane potentials as the basis for electrical signaling. Yet, in mammals and insects, neuronal and glial membrane potentials can reversibly depolarize to zero, shutting down neural function by the process of spreading depolarization (SD) that collapses the ion gradients across membranes. SD is not evident in all metazoan taxa with centralized nervous systems. We consider the occurrence and similarities of SD in different animals and suggest that it is an emergent property of nervous systems that have evolved to control complex behaviors requiring energetically expensive, rapid information processing in a tightly regulated extracellular environment. Whether SD is beneficial or not in mammals remains an open question. However, in insects, it is associated with the response to harsh environments and may provide an energetic advantage that improves the chances of survival. The remarkable similarity of SD in diverse taxa supports a model systems approach to understanding the mechanistic underpinning of human neuropathology associated with migraine, stroke, and traumatic brain injury.
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Affiliation(s)
- R Meldrum Robertson
- Department of Biology and Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - Ken D Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida
| | - R David Andrew
- Department of Biomedical and Molecular Sciences and Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
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13
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Abstract
The Drosophila melanogaster foraging (for) gene is a well-established example of a gene with major effects on behavior and natural variation. This gene is best known for underlying the behavioral strategies of rover and sitter foraging larvae, having been mapped and named for this phenotype. Nevertheless, in the last three decades an extensive array of studies describing for's role as a modifier of behavior in a wide range of phenotypes, in both Drosophila and other organisms, has emerged. Furthermore, recent work reveals new insights into the genetic and molecular underpinnings of how for affects these phenotypes. In this article, we discuss the history of the for gene and its role in natural variation in behavior, plasticity, and behavioral pleiotropy, with special attention to recent findings on the molecular structure and transcriptional regulation of this gene.
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Affiliation(s)
- Ina Anreiter
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada;
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada;
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14
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Genome-Wide Association Analysis of Anoxia Tolerance in Drosophila melanogaster. G3-GENES GENOMES GENETICS 2019; 9:2989-2999. [PMID: 31311780 PMCID: PMC6723132 DOI: 10.1534/g3.119.400421] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
As the genetic bases to variation in anoxia tolerance are poorly understood, we used the Drosophila Genetics Reference Panel (DGRP) to conduct a genome-wide association study (GWAS) of anoxia tolerance in adult and larval Drosophila melanogaster Survival ranged from 0-100% in adults exposed to 6 h of anoxia and from 20-98% for larvae exposed to 1 h of anoxia. Anoxia tolerance had a broad-sense heritability of 0.552 in adults and 0.433 in larvae. Larval and adult phenotypes were weakly correlated but the anoxia tolerance of adult males and females were strongly correlated. The GWA identified 180 SNPs in adults and 32 SNPs in larvae associated with anoxia tolerance. Gene ontology enrichment analysis indicated that many of the 119 polymorphic genes associated with adult anoxia-tolerance were associated with ionic transport or immune function. In contrast, the 22 polymorphic genes associated with larval anoxia-tolerance were mostly associated with regulation of transcription and DNA replication. RNAi of mapped genes generally supported the hypothesis that disruption of these genes reduces anoxia tolerance. For two ion transport genes, we tested predicted directional and sex-specific effects of SNP alleles on adult anoxia tolerance and found strong support in one case but not the other. Correlating our phenotype to prior DGRP studies suggests that genes affecting anoxia tolerance also influence stress-resistance, immune function and ionic balance. Overall, our results provide evidence for multiple new potential genetic influences on anoxia tolerance and provide additional support for important roles of ion balance and immune processes in determining variation in anoxia tolerance.
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15
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Mahneva O, Caplan SL, Ivko P, Dawson-Scully K, Milton SL. NO/cGMP/PKG activation protects Drosophila cells subjected to hypoxic stress. Comp Biochem Physiol C Toxicol Pharmacol 2019; 223:106-114. [PMID: 31150868 DOI: 10.1016/j.cbpc.2019.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 01/28/2023]
Abstract
The anoxia-tolerant fruit fly, Drosophila melanogaster, has routinely been used to examine cellular mechanisms responsible for anoxic and oxidative stress resistance. Nitric oxide (NO), an important cellular signaling molecule, and its downstream activation of cGMP-dependent protein kinase G (PKG) has been implicated as a protective mechanism against ischemic injury in diverse animal models from insects to mammals. In Drosophila, increased PKG signaling results in increased survival of animals exposed to anoxic stress. To determine if activation of the NO/cGMP/PKG pathway is protective at the cellular level, the present study employed a pharmacological protocol to mimic hypoxic injury in Drosophila S2 cells. The commonly used S2 cell line was derived from a primary culture of late stage (20-24 h old) Drosophila melanogaster embryos. Hypoxic stress was induced by exposure to either sodium azide (NaN3) or cobalt chloride (CoCl2). During chemical hypoxic stress, NO/cGMP/PKG activation protected against cell death and this mechanism involved modulation of downstream mitochondrial ATP-sensitive potassium ion channels (mitoKATP). The cellular protection afforded by NO/cGMP/PKG activation during ischemia-like stress may be an adaptive cytoprotective mechanism and modulation of this signaling cascade could serve as a potential therapeutic target for protection against hypoxia or ischemia-induced cellular injury.
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Affiliation(s)
- Olena Mahneva
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Stacee Lee Caplan
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Polina Ivko
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
| | - Sarah L Milton
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.
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Xiao C, Bayat Fard N, Brzezinski K, Robertson RM, Chippindale AK. Experimental evolution of response to anoxia in Drosophila melanogaster: recovery of locomotion following CO 2 or N 2 exposure. ACTA ACUST UNITED AC 2019; 222:jeb.199521. [PMID: 31285245 DOI: 10.1242/jeb.199521] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 07/02/2019] [Indexed: 12/23/2022]
Abstract
Many insects enter coma upon exposure to anoxia, a feature routinely exploited by experimentalists to handle them. But the genetic and physiological bases of anoxic coma induction and recovery are only partially understood, as are the long-term consequences for the animal's performance. We examined three populations of Drosophila melanogaster (designated B) that have been inadvertently under selection for rapid recovery from CO2 exposure for nearly 40 years (around 1000 generations) resulting from routine maintenance practices. We contrasted CO2 and N2 (presumed a less reactive gas) knockdown and recovery times of these B flies with six populations of common ancestry (A and C populations) that were not exposed to CO2 over the same period. We found that B populations showed faster and more consistent locomotor recovery than A or C populations after CO2 knockdown, a result also observed with N2 knockdown. A and C populations showed much higher variance in recovery time after CO2 exposure than after N2 exposure, suggesting gas-specific effects on pathways associated with locomotor recovery. Although these selection treatments result in considerable variation in life history attributes and body size, with the characteristic intermediacy of B populations, their superiority in resistance to gas exposure and locomotor recovery suggests that this is a direct consequence of prior repeated exposure to anoxia, broadly, and CO2, specifically. Hence we describe a powerful new evolutionary model for the genetic and physiological investigation of anoxic coma in insects.
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Affiliation(s)
- Chengfeng Xiao
- Department of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6
| | - Niki Bayat Fard
- Department of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6
| | - Kaylen Brzezinski
- Department of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6
| | | | - Adam K Chippindale
- Department of Biology, Queen's University, Kingston, ON, Canada, K7L 3N6
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17
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Kelly SP, Dawson-Scully K. Natural polymorphism in protein kinase G modulates functional senescence in D rosophila melanogaster. J Exp Biol 2019; 222:jeb.199364. [PMID: 30910834 DOI: 10.1242/jeb.199364] [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: 01/08/2019] [Accepted: 03/19/2019] [Indexed: 11/20/2022]
Abstract
The common fruit fly, Drosophila melanogaster, is a well-characterized model for neurological disorders and is widely used to investigate the biology of aging, stress tolerance and pleiotropy. The foraging (for) gene encodes a cGMP-dependent protein kinase (PKG), which has been implicated in several behavioral phenotypes including feeding, sleep, learning and memory, and environmental stress tolerance. We used the well-established Drosophila activity monitor (DAM) to investigate the effects of the conserved NO/cGMP/PKG signaling pathway on functional senescence. Our results show that the polymorphic for gene confers protection during low oxygen stress at the expense of longevity and a decline in locomotor activity with age in D. melanogaster, which suggests a novel role for the PKG pathway in healthy aging and senescence.
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Affiliation(s)
- Stephanie P Kelly
- Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL 33431, USA
| | - Ken Dawson-Scully
- Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL 33431, USA
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Huo D, Sun L, Zhang L, Ru X, Liu S, Yang X, Yang H. Global-warming-caused changes of temperature and oxygen alter the proteomic profile of sea cucumber Apostichopus japonicus. J Proteomics 2019; 193:27-43. [DOI: 10.1016/j.jprot.2018.12.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 12/05/2018] [Accepted: 12/14/2018] [Indexed: 12/28/2022]
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19
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Bollinger WL, Sial N, Dawson-Scully K. BK channels and a cGMP-dependent protein kinase (PKG) function through independent mechanisms to regulate the tolerance of synaptic transmission to acute oxidative stress at the Drosophila larval neuromuscular junction. J Neurogenet 2018; 32:246-255. [DOI: 10.1080/01677063.2018.1500571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Wesley L. Bollinger
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
| | - Nadia Sial
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
- Brain Institute Research Scholars Program, Florida Atlantic University, Boca Raton, FL, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, USA
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20
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Kelly SP, Risley MG, Miranda LE, Dawson-Scully K. Contribution of a natural polymorphism in protein kinase G modulates electroconvulsive seizure recovery in Drosophila melanogaster. ACTA ACUST UNITED AC 2018; 221:jeb.179747. [PMID: 29798846 DOI: 10.1242/jeb.179747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/21/2018] [Indexed: 11/20/2022]
Abstract
Drosophila melanogaster is a well-characterized model for neurological disorders and is widely used for investigating causes of altered neuronal excitability leading to seizure-like behavior. One method used to analyze behavioral output of neuronal perturbance is recording the time to locomotor recovery from an electroconvulsive shock. Based on this behavior, we sought to quantify seizure susceptibility in larval D. melanogaster with differences in the enzymatic activity levels of a major protein, cGMP-dependent protein kinase (PKG). PKG, encoded by foraging, has two natural allelic variants and has previously been implicated in several important physiological characteristics including: foraging patterns, learning and memory, and environmental stress tolerance. The well-established NO/cGMP/PKG signaling pathway found in the fly, which potentially targets downstream K+ channel(s), ultimately impacts membrane excitability, leading to our hypothesis: altering PKG enzymatic activity modulates time to recovery from an electroconvulsive seizure. Our results show that by both genetically and pharmacologically increasing PKG enzymatic activity, we can decrease the locomotor recovery time from an electroconvulsive seizure in larval D. melanogaster.
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Affiliation(s)
- Stephanie P Kelly
- Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL 33431, USA
| | - Monica G Risley
- Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL 33431, USA
| | - Leonor E Miranda
- Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL 33431, USA
| | - Ken Dawson-Scully
- Florida Atlantic University, Department of Biological Sciences, Boca Raton, FL 33431, USA
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21
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Risley MG, Kelly SP, Minnerly J, Jia K, Dawson-Scully K. egl-4 modulates electroconvulsive seizure duration in C. elegans. INVERTEBRATE NEUROSCIENCE 2018; 18:8. [PMID: 29845318 DOI: 10.1007/s10158-018-0211-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/30/2018] [Indexed: 12/16/2022]
Abstract
Increased neuronal excitability causes seizures with debilitating symptoms. Effective and noninvasive treatments are limited for easing symptoms, partially due to the complexity of the disorder and lack of knowledge of specific molecular faults. An unexplored, novel target for seizure therapeutics is the cGMP/protein kinase G (PKG) pathway, which targets downstream K+ channels, a mechanism similar to Retigabine, a recently FDA-approved antiepileptic drug. Our results demonstrate that increased PKG activity decreased seizure duration in C. elegans utilizing a recently developed electroconvulsive seizure assay. While the fly is a well-established seizure model, C. elegans are an ideal yet unexploited model which easily uptakes drugs and can be utilized for high-throughput screens. In this study, we show that treating the worms with either a potassium channel opener, Retigabine or published pharmaceuticals that increase PKG activity, significantly reduces seizure recovery times. Our results suggest that PKG signaling modulates downstream K+ channel conductance to control seizure recovery time in C. elegans. Hence, we provide powerful evidence, suggesting that pharmacological manipulation of the PKG signaling cascade may control seizure duration across phyla.
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Affiliation(s)
- Monica G Risley
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Stephanie P Kelly
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Justin Minnerly
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Kailiang Jia
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA.,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL, 33431, USA. .,International Max-Planck Research School (IMPRS) for Brain and Behavior, Boca Raton, FL, 33431, USA.
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22
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McConnell MW, Fitzpatrick MJ. 'Foraging' for a place to lay eggs: A genetic link between foraging behaviour and oviposition preferences. PLoS One 2017; 12:e0179362. [PMID: 28622389 PMCID: PMC5473555 DOI: 10.1371/journal.pone.0179362] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/30/2017] [Indexed: 11/18/2022] Open
Abstract
Gravid female arthropods in search of egg-laying substrates embark on foraging-like forays: they survey the environment assessing multiple patches, tasting each with their tarsi and proboscis, and then, if interested, they deposit an egg (or eggs). In fruit flies, Drosophila melanogaster, allelic variation in the foraging gene (for) underlies the rover/sitter foraging behaviour polymorphism. Rover flies (forR) are more active foragers (both within and between food patches) compared to sitters (fors). In nematodes, Caenorhabditis elegans, a mutation in egl-4, the ortholog of for, leads to aberrations in egg laying. Given this and the notion that females may 'forage' for a place to oviposit, we hypothesized that for may underlie egg-laying decisions in the fruit fly. Indeed, when given a choice between patches of low- and high-nutrient availability, rovers lay significantly more eggs on the low-nutrient patches than sitters and also a sitter mutant (fors2). We confirm the role of for by inducing rover-like oviposition preferences in a sitter fly using the transgenic overexpression of for-mRNA in the nervous system.
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Affiliation(s)
- Murray W. McConnell
- Integrative Behaviour & Neuroscience Group, Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Mark J. Fitzpatrick
- Integrative Behaviour & Neuroscience Group, Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON, Canada
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, ON, Canada
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
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23
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Xiao C, Robertson RM. White - cGMP Interaction Promotes Fast Locomotor Recovery from Anoxia in Adult Drosophila. PLoS One 2017; 12:e0168361. [PMID: 28060942 PMCID: PMC5218474 DOI: 10.1371/journal.pone.0168361] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Accepted: 11/30/2016] [Indexed: 12/18/2022] Open
Abstract
Increasing evidence indicates that the white (w) gene in Drosophila possesses extra-retinal functions in addition to its classical role in eye pigmentation. We have previously shown that w+ promotes fast and consistent locomotor recovery from anoxia, but how w+ modulates locomotor recovery is largely unknown. Here we show that in the absence of w+, several PDE mutants, especially cyclic guanosine monophosphate (cGMP)-specific PDE mutants, display wildtype-like fast locomotor recovery from anoxia, and that during the night time, locomotor recovery was light-sensitive in white-eyed mutant w1118, and light-insensitive in PDE mutants under w1118 background. Data indicate the involvement of cGMP in the modulation of recovery timing and presumably, light-evoked cGMP fluctuation is associated with light sensitivity of locomotor recovery. This was further supported by the observations that w-RNAi-induced delay of locomotor recovery was completely eliminated by upregulation of cGMP through multiple approaches, including PDE mutation, simultaneous overexpression of an atypical soluble guanylyl cyclase Gyc88E, or sildenafil feeding. Lastly, prolonged sildenafil feeding promoted fast locomotor recovery from anoxia in w1118. Taken together, these data suggest that a White-cGMP interaction modulates the timing of locomotor recovery from anoxia.
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Affiliation(s)
- Chengfeng Xiao
- Department of Biology, Queen’s University, Kingston, Ontario, Canada
- * E-mail:
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24
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Sokolowski HM, Vasquez OE, Unternaehrer E, Sokolowski DJ, Biergans SD, Atkinson L, Gonzalez A, Silveira PP, Levitan R, O'Donnell KJ, Steiner M, Kennedy J, Meaney MJ, Fleming AS, Sokolowski MB. The Drosophila foraging gene human orthologue PRKG1 predicts individual differences in the effects of early adversity on maternal sensitivity. COGNITIVE DEVELOPMENT 2016; 42:62-73. [PMID: 28827895 DOI: 10.1016/j.cogdev.2016.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
There is variation in the extent to which childhood adverse experience affects adult individual differences in maternal behavior. Genetic variation in the animal foraging gene, which encodes a cGMP-dependent protein kinase, contributes to variation in the responses of adult fruit flies, Drosophila melanogaster, to early life adversity and is also known to play a role in maternal behavior in social insects. Here we investigate genetic variation in the human foraging gene (PRKG1) as a predictor of individual differences in the effects of early adversity on maternal behavior in two cohorts. We show that the PRKG1 genetic polymorphism rs2043556 associates with maternal sensitivity towards their infants. We also show that rs2043556 moderates the association between self-reported childhood adversity of the mother and her later maternal sensitivity. Mothers with the TT allele of rs2043556 appeared buffered from the effects of early adversity, whereas mothers with the presence of a C allele were not. Our study used the Toronto Longitudinal Cohort (N=288 mother-16 month old infant pairs) and the Maternal Adversity and Vulnerability and Neurodevelopment Cohort (N=281 mother-18 month old infant pairs). Our findings expand the literature on the contributions of both genetics and gene-environment interactions to maternal sensitivity, a salient feature of the early environment relevant for child neurodevelopment.
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Affiliation(s)
- H Moriah Sokolowski
- Department of Psychology, Brain and Mind Institute, The University of Western Ontario, Westminster Hall, Room 325, London, Ontario, Canada, N6A 3K7
| | - Oscar E Vasquez
- Department of Ecology and Evolutionary Biology, 25 Wilcocks St. University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Eva Unternaehrer
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3
| | - Dustin J Sokolowski
- Department of Biology, University of Western, Ontario, Toronto, Canada, N6A 3K7
| | - Stephanie D Biergans
- Department of Ecology and Evolutionary Biology, 25 Wilcocks St. University of Toronto, Toronto, Ontario, Canada, M5S 3B2
| | - Leslie Atkinson
- Department of Psychology, Ryerson University, Toronto, Ontario, Canada, M5B2K3
| | - Andrea Gonzalez
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Department of Psychiatry and Behavioural Neurosciences, Offord Centre for Child Studies, McMaster Innovation Park, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1
| | - Patricia P Silveira
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3
| | - Robert Levitan
- Women's Health Concerns Clinic, St. Joseph's Healthcare, 50 Charlton Avenue East, Hamilton, Ontario, Canada, L8G 5E4
| | - Kieran J O'Donnell
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St West, Suite 1400, Toronto, Ontario Canada M5G 1Z8
| | - Meir Steiner
- Department of Psychiatry and Behavioral Neurosciences, McMaster University, Department of Psychiatry and Behavioural Neurosciences, Offord Centre for Child Studies, McMaster Innovation Park, 1280 Main Street West, Hamilton, ON, Canada, L8S 4K1.,Women's Health Concerns Clinic, St. Joseph's Healthcare, 50 Charlton Avenue East, Hamilton, Ontario, Canada, L8G 5E4
| | - James Kennedy
- Department of Psychiatry, University of Toronto and Centre for Addiction an Mental Health, 33 Russell St, Toronto, Ontario, M5S 3M1
| | - Michael J Meaney
- Ludmer Centre for Neuroinformatics and Mental Health, Douglas Mental Health University Institute, McGill University, 6875, Boulevard LaSalle, Montréal, Québec, Canada H4H 1R3.,Singapore Institute for Clinical Science, Brenner Centre for Molecular Medicine 30 Medical Drive, Singapore 117609.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St West, Suite 1400, Toronto, Ontario Canada M5G 1Z8
| | - Alison S Fleming
- Department of Psychology, 100 St. George Street, Sidney Smith Hall Toronto, Ontario, Canada M5S 3G3
| | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, 25 Wilcocks St. University of Toronto, Toronto, Ontario, Canada, M5S 3B2.,Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), 180 Dundas St West, Suite 1400, Toronto, Ontario Canada M5G 1Z8
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25
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Krill JL, Dawson-Scully K. cGMP-Dependent Protein Kinase Inhibition Extends the Upper Temperature Limit of Stimulus-Evoked Calcium Responses in Motoneuronal Boutons of Drosophila melanogaster Larvae. PLoS One 2016; 11:e0164114. [PMID: 27711243 PMCID: PMC5053426 DOI: 10.1371/journal.pone.0164114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 09/20/2016] [Indexed: 12/31/2022] Open
Abstract
While the mammalian brain functions within a very narrow range of oxygen concentrations and temperatures, the fruit fly, Drosophila melanogaster, has employed strategies to deal with a much wider range of acute environmental stressors. The foraging (for) gene encodes the cGMP-dependent protein kinase (PKG), has been shown to regulate thermotolerance in many stress-adapted species, including Drosophila, and could be a potential therapeutic target in the treatment of hyperthermia in mammals. Whereas previous thermotolerance studies have looked at the effects of PKG variation on Drosophila behavior or excitatory postsynaptic potentials at the neuromuscular junction (NMJ), little is known about PKG effects on presynaptic mechanisms. In this study, we characterize presynaptic calcium ([Ca2+]i) dynamics at the Drosophila larval NMJ to determine the effects of high temperature stress on synaptic transmission. We investigated the neuroprotective role of PKG modulation both genetically using RNA interference (RNAi), and pharmacologically, to determine if and how PKG affects presynaptic [Ca2+]i dynamics during hyperthermia. We found that PKG activity modulates presynaptic neuronal Ca2+ responses during acute hyperthermia, where PKG activation makes neurons more sensitive to temperature-induced failure of Ca2+ flux and PKG inhibition confers thermotolerance and maintains normal Ca2+ dynamics under the same conditions. Targeted motoneuronal knockdown of PKG using RNAi demonstrated that decreased PKG expression was sufficient to confer thermoprotection. These results demonstrate that the PKG pathway regulates presynaptic motoneuronal Ca2+ signaling to influence thermotolerance of presynaptic function during acute hyperthermia.
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Affiliation(s)
- Jennifer L. Krill
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, United States of America
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida, United States of America
- * E-mail:
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26
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Spong KE, Andrew RD, Robertson RM. Mechanisms of spreading depolarization in vertebrate and insect central nervous systems. J Neurophysiol 2016; 116:1117-27. [PMID: 27334953 PMCID: PMC5013167 DOI: 10.1152/jn.00352.2016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/15/2016] [Indexed: 11/22/2022] Open
Abstract
Spreading depolarization (SD) is generated in the central nervous systems of both vertebrates and invertebrates. SD manifests as a propagating wave of electrical depression caused by a massive redistribution of ions. Mammalian SD underlies a continuum of human pathologies from migraine to stroke damage, whereas insect SD is associated with environmental stress-induced neural shutdown. The general cellular mechanisms underlying SD seem to be evolutionarily conserved throughout the animal kingdom. In particular, SD in the central nervous system of Locusta migratoria and Drosophila melanogaster has all the hallmarks of mammalian SD. Locust SD is easily induced and monitored within the metathoracic ganglion (MTG) and can be modulated both pharmacologically and by preconditioning treatments. The finding that the fly brain supports repetitive waves of SD is relatively recent but noteworthy, since it provides a genetically tractable model system. Due to the human suffering caused by SD manifestations, elucidating control mechanisms that could ultimately attenuate brain susceptibility is essential. Here we review mechanisms of SD focusing on the similarities between mammalian and insect systems. Additionally we discuss advantages of using invertebrate model systems and propose insect SD as a valuable model for providing new insights to mammalian SD.
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Affiliation(s)
- Kristin E Spong
- Department of Biology, Queen's University, Kingston, Ontario, Canada
| | - R David Andrew
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada; and Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - R Meldrum Robertson
- Department of Biology, Queen's University, Kingston, Ontario, Canada; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada; and Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
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27
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Money TGA, Sproule MKJ, Cross KP, Robertson RM. Octopamine stabilizes conduction reliability of an unmyelinated axon during hypoxic stress. J Neurophysiol 2016; 116:949-59. [PMID: 27281750 PMCID: PMC5009204 DOI: 10.1152/jn.00354.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/03/2016] [Indexed: 11/22/2022] Open
Abstract
Mechanisms that could mitigate the effects of hypoxia on neuronal signaling are incompletely understood. We show that axonal performance of a locust visual interneuron varied depending on oxygen availability. To induce hypoxia, tracheae supplying the thoracic nervous system were surgically lesioned and action potentials in the axon of the descending contralateral movement detector (DCMD) neuron passing through this region were monitored extracellularly. The conduction velocity and fidelity of action potentials decreased throughout a 45-min experiment in hypoxic preparations, whereas conduction reliability remained constant when the tracheae were left intact. The reduction in conduction velocity was exacerbated for action potentials firing at high instantaneous frequencies. Bath application of octopamine mitigated the loss of conduction velocity and fidelity. Action potential conduction was more vulnerable in portions of the axon passing through the mesothoracic ganglion than in the connectives between ganglia, indicating that hypoxic modulation of the extracellular environment of the neuropil has an important role to play. In intact locusts, octopamine and its antagonist, epinastine, had effects on the entry to, and recovery from, anoxic coma consistent with octopamine increasing overall neural performance during hypoxia. These effects could have functional relevance for the animal during periods of environmental or activity-induced hypoxia.
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Affiliation(s)
- T G A Money
- Department of Biology, Queen's University, Kingston, Ontario, Canada; and
| | - M K J Sproule
- Department of Biology, Queen's University, Kingston, Ontario, Canada; and
| | - K P Cross
- Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
| | - R M Robertson
- Department of Biology, Queen's University, Kingston, Ontario, Canada; and Centre for Neuroscience Studies, Queen's University, Kingston, Ontario, Canada
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28
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Spong KE, Rodríguez EC, Robertson RM. Spreading depolarization in the brain of Drosophila is induced by inhibition of the Na+/K+-ATPase and mitigated by a decrease in activity of protein kinase G. J Neurophysiol 2016; 116:1152-60. [PMID: 27358319 PMCID: PMC5013169 DOI: 10.1152/jn.00353.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/22/2016] [Indexed: 11/22/2022] Open
Abstract
Spreading depolarization (SD) is characterized by a massive redistribution of ions accompanied by an arrest in electrical activity that slowly propagates through neural tissue. It has been implicated in numerous human pathologies, including migraine, stroke, and traumatic brain injury, and thus the elucidation of control mechanisms underlying the phenomenon could have many health benefits. Here, we demonstrate the occurrence of SD in the brain of Drosophila melanogaster, providing a model system, whereby cellular mechanisms can be dissected using molecular genetic approaches. Propagating waves of SD were reliably induced by disrupting the extracellular potassium concentration ([K(+)]o), either directly or by inhibition of the Na(+)/K(+)-ATPase with ouabain. The disturbance was monitored by recording the characteristic surges in [K(+)]o using K(+)-sensitive microelectrodes or by monitoring brain activity by measuring direct current potential. With the use of wild-type flies, we show that young adults are more resistant to SD compared with older adults, evidenced by shorter bouts of SD activity and attenuated [K(+)]o disturbances. Furthermore, we show that the susceptibility to SD differs between wild-type flies and w1118 mutants, demonstrating that our ouabain model is influenced by genetic strain. Lastly, flies with low levels of protein kinase G (PKG) had increased latencies to onset of both ouabain-induced SD and anoxic depolarization compared with flies with higher levels. Our findings implicate the PKG pathway as a modulator of SD in the fly brain, and given the conserved nature of the signaling pathway, it could likely play a similar role during SD in the mammalian central nervous system.
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Affiliation(s)
- Kristin E Spong
- Department of Biology, Queen's University, Biosciences Complex, Kingston, Ontario, Canada
| | - Esteban C Rodríguez
- Department of Biology, Queen's University, Biosciences Complex, Kingston, Ontario, Canada
| | - R Meldrum Robertson
- Department of Biology, Queen's University, Biosciences Complex, Kingston, Ontario, Canada
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29
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Chia KKM, Liu CC, Hamilton EJ, Garcia A, Fry NA, Hannam W, Figtree GA, Rasmussen HH. Stimulation of the cardiac myocyte Na+-K+ pump due to reversal of its constitutive oxidative inhibition. Am J Physiol Cell Physiol 2015; 309:C239-50. [PMID: 26084308 DOI: 10.1152/ajpcell.00392.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 06/09/2015] [Indexed: 11/22/2022]
Abstract
Protein kinase C can activate NADPH oxidase and induce glutathionylation of the β1-Na(+)-K(+) pump subunit, inhibiting activity of the catalytic α-subunit. To examine if signaling of nitric oxide-induced soluble guanylyl cyclase (sGC)/cGMP/protein kinase G can cause Na(+)-K(+) pump stimulation by counteracting PKC/NADPH oxidase-dependent inhibition, cardiac myocytes were exposed to ANG II to activate NADPH oxidase and inhibit Na(+)-K(+) pump current (Ip). Coexposure to 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) to stimulate sGC prevented the decrease of Ip. Prevention of the decrease was abolished by inhibition of protein phosphatases (PP) 2A but not by inhibition of PP1, and it was reproduced by an activator of PP2A. Consistent with a reciprocal relationship between β1-Na(+)-K(+) pump subunit glutathionylation and pump activity, YC-1 decreased ANG II-induced β1-subunit glutathionylation. The decrease induced by YC-1 was abolished by a PP2A inhibitor. YC-1 decreased phosphorylation of the cytosolic p47(phox) NADPH oxidase subunit and its coimmunoprecipitation with the membranous p22(phox) subunit, and it decreased O2 (·-)-sensitive dihydroethidium fluorescence of myocytes. Addition of recombinant PP2A to myocyte lysate decreased phosphorylation of p47(phox) indicating the subunit could be a substrate for PP2A. The effects of YC-1 to decrease coimmunoprecipitation of p22(phox) and p47(phox) NADPH oxidase subunits and decrease β1-Na(+)-K(+) pump subunit glutathionylation were reproduced by activation of nitric oxide-dependent receptor signaling. We conclude that sGC activation in cardiac myocytes causes a PP2A-dependent decrease in NADPH oxidase activity and a decrease in β1 pump subunit glutathionylation. This could account for pump stimulation with neurohormonal oxidative stress expected in vivo.
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Affiliation(s)
- Karin K M Chia
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia; Royal Brisbane and Women's Hospital, The University of Queensland, Queensland, Australia; and
| | - Chia-Chi Liu
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Elisha J Hamilton
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Alvaro Garcia
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Natasha A Fry
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - William Hannam
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia
| | - Gemma A Figtree
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia; Department of Cardiology, Royal North Shore Hospital, St. Leonards, Australia
| | - Helge H Rasmussen
- North Shore Heart Research Group, Kolling Medical Research Institute, University of Sydney, Sydney, Australia; Department of Cardiology, Royal North Shore Hospital, St. Leonards, Australia
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Chardonnet F, Capdevielle-Dulac C, Chouquet B, Joly N, Harry M, Le Ru B, Silvain JF, Kaiser L. Food searching behaviour of a Lepidoptera pest species is modulated by the foraging gene polymorphism. ACTA ACUST UNITED AC 2015; 217:3465-73. [PMID: 25274324 DOI: 10.1242/jeb.108258] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The extent of damage to crop plants from pest insects depends on the foraging behaviour of the insect's feeding stage. Little is known, however, about the genetic and molecular bases of foraging behaviour in phytophagous pest insects. The foraging gene (for), a candidate gene encoding a PKG-I, has an evolutionarily conserved function in feeding strategies. Until now, for had never been studied in Lepidoptera, which includes major pest species. The cereal stem borer Sesamia nonagrioides is therefore a relevant species within this order with which to study conservation of and polymorphism in the for gene, and its role in foraging - a behavioural trait that is directly associated with plant injuries. Full sequencing of for cDNA in S. nonagrioides revealed a high degree of conservation with other insect taxa. Activation of PKG by a cGMP analogue increased larval foraging activity, measured by how frequently larvae moved between food patches in an actimeter. We found one non-synonymous allelic variation in a natural population that defined two allelic variants. These variants presented significantly different levels of foraging activity, and the behaviour was positively correlated to gene expression levels. Our results show that for gene function is conserved in this species of Lepidoptera, and describe an original case of a single nucleotide polymorphism associated with foraging behaviour variation in a pest insect. By illustrating how variation in this single gene can predict phenotype, this work opens new perspectives into the evolutionary context of insect adaptation to plants, as well as pest management.
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Affiliation(s)
- Floriane Chardonnet
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Claire Capdevielle-Dulac
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Bastien Chouquet
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Nicolas Joly
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Myriam Harry
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Bruno Le Ru
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France icipe - African Insect Science for Food and Health, Duduville Campus, Kasarani, PO Box 30772-00100, Nairobi, Kenya
| | - Jean-François Silvain
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France
| | - Laure Kaiser
- Laboratoire Evolution Génome et Spéciation, CNRS UPR 9034, IRD UR 072 and Université Paris Sud Orsay, 1 Avenue de la Terrasse, 91198 Gif sur Yvette, France INRA, UMR 1392, Institut d'Ecologie et des Sciences de l'Environnement de Paris, France
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Benasayag-Meszaros R, Risley MG, Hernandez P, Fendrich M, Dawson-Scully K. Pushing the limit: examining factors that affect anoxia tolerance in a single genotype of adult D. melanogaster. Sci Rep 2015; 5:9204. [PMID: 25777190 PMCID: PMC4361850 DOI: 10.1038/srep09204] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 02/24/2015] [Indexed: 12/31/2022] Open
Abstract
Drosophila melanogaster is a promiscuous species that inhabits a large range of harsh environments including flooded habitats and varying temperature changes. To survive these environments, fruit flies have adapted mechanisms of tolerance that allow them to thrive. During exposure to anoxic stress, fruit flies and other poikilotherms enter into a reversible, protective coma. This coma can be manipulated based on controlled environmental conditions inside the laboratory. Here we utilize a common laboratory raised strain of D. melanogaster to characterize adaptation abilities to better understand coma recovery and survival limitations. Our goal is to mimic the fly's natural environments (wet anoxia) and relate findings to a typical gas induced environment (dry anoxia) that is commonly used in a laboratory. Despite the abundance of research regarding acute and chronic anoxic exposure and cold stress, the literature is lacking evidence linking anoxic stress with variable environmental conditions such as animal age and stress duration. We present novel ways to assess coma recovery and survival using readily available laboratory tools. Our findings suggest that younger age, exposure to colder temperatures and wet environments increase resistance to anoxic stress.
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Affiliation(s)
- Raquel Benasayag-Meszaros
- Florida Atlantic University, Department of Biological Sciences, 5353 Parkside Drive, Jupiter, FL. 33458, USA
| | - Monica G Risley
- Florida Atlantic University, Department of Biological Sciences, 5353 Parkside Drive, Jupiter, FL. 33458, USA
| | - Priscilla Hernandez
- Florida Atlantic University, Department of Biological Sciences, 5353 Parkside Drive, Jupiter, FL. 33458, USA
| | - Margo Fendrich
- Florida Atlantic University, Department of Biological Sciences, 5353 Parkside Drive, Jupiter, FL. 33458, USA
| | - Ken Dawson-Scully
- Florida Atlantic University, Department of Biological Sciences, 5353 Parkside Drive, Jupiter, FL. 33458, USA
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Hou N, Armstrong GAB, Chakraborty-Chatterjee M, Sokolowski MB, Robertson RM. Na+-K+-ATPase trafficking induced by heat shock pretreatment correlates with increased resistance to anoxia in locusts. J Neurophysiol 2014; 112:814-23. [PMID: 24848469 PMCID: PMC4122745 DOI: 10.1152/jn.00201.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 05/17/2014] [Indexed: 01/02/2023] Open
Abstract
The sensitivity of insect nervous systems to anoxia can be modulated genetically and pharmacologically, but the cellular mechanisms responsible are poorly understood. We examined the effect of a heat shock pretreatment (HS) on the sensitivity of the locust (Locusta migratoria) nervous system to anoxia induced by water immersion. Prior HS made locusts more resistant to anoxia by increasing the time taken to enter a coma and by reducing the time taken to recover the ability to stand. Anoxic comas were accompanied by surges of extracellular potassium ions in the neuropile of the metathoracic ganglion, and HS reduced the time taken for clearance of excess extracellular potassium ions. This could not be attributed to a decrease in the activity of protein kinase G, which was increased by HS. In homogenates of the metathoracic ganglion, HS had only a mild effect on the activity of Na(+)-K(+)-ATPase. However, we demonstrated that HS caused a threefold increase in the immunofluorescent localization of the α-subunit of Na(+)-K(+)-ATPase in metathoracic neuronal plasma membranes relative to background labeling of the nucleus. We conclude that HS induced trafficking of Na(+)-K(+)-ATPase into neuronal plasma membranes and suggest that this was at least partially responsible for the increased resistance to anoxia and the increased rate of recovery of neural function after a disturbance of K(+) homeostasis.
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Affiliation(s)
- Nicholas Hou
- Department of Biology, Queen's University, Kingston, Ontario, Canada; and
| | - Gary A B Armstrong
- Department of Biology, Queen's University, Kingston, Ontario, Canada; and
| | | | - Marla B Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
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Kohn NR, Reaume CJ, Moreno C, Burns JG, Sokolowski MB, Mery F. Social environment influences performance in a cognitive task in natural variants of the foraging gene. PLoS One 2013; 8:e81272. [PMID: 24349049 PMCID: PMC3861308 DOI: 10.1371/journal.pone.0081272] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 10/10/2013] [Indexed: 11/19/2022] Open
Abstract
In Drosophila melanogaster, natural genetic variation in the foraging gene affects the foraging behaviour of larval and adult flies, larval reward learning, adult visual learning, and adult aversive training tasks. Sitters (for(s)) are more sedentary and aggregate within food patches whereas rovers (for(R)) have greater movement within and between food patches, suggesting that these natural variants are likely to experience different social environments. We hypothesized that social context would differentially influence rover and sitter behaviour in a cognitive task. We measured adult rover and sitter performance in a classical olfactory training test in groups and alone. All flies were reared in groups, but fly training and testing were done alone and in groups. Sitters trained and tested in a group had significantly higher learning performances compared to sitters trained and tested alone. Rovers performed similarly when trained and tested alone and in a group. In other words, rovers learning ability is independent of group training and testing. This suggests that sitters may be more sensitive to the social context than rovers. These differences in learning performance can be altered by pharmacological manipulations of PKG activity levels, the foraging (for) gene's gene product. Learning and memory is also affected by the type of social interaction (being in a group of the same strain or in a group of a different strain) in rovers, but not in sitters. These results suggest that for mediates social learning and memory in D. melanogaster.
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Affiliation(s)
- Nancy R. Kohn
- Laboratoire Evolution, Génome et Spéciation, CNRS, Gif sur Yvette, France
- Department of Biology, University of Missouri–Saint Louis, Saint Louis, Missouri, United States of America
| | - Christopher J. Reaume
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Celine Moreno
- Laboratoire Evolution, Génome et Spéciation, CNRS, Gif sur Yvette, France
| | - James G. Burns
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Marla B. Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, Canada
| | - Frederic Mery
- Laboratoire Evolution, Génome et Spéciation, CNRS, Gif sur Yvette, France
- * E-mail:
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Milton SL, Dawson-Scully K. Alleviating brain stress: what alternative animal models have revealed about therapeutic targets for hypoxia and anoxia. FUTURE NEUROLOGY 2013; 8:287-301. [PMID: 25264428 DOI: 10.2217/fnl.13.12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
While the mammalian brain is highly dependent on oxygen, and can withstand only a few minutes without air, there are both vertebrate and invertebrate examples of anoxia tolerance. One example is the freshwater turtle, which can withstand days without oxygen, thus providing a vertebrate model with which to examine the physiology of anoxia tolerance without the pathology seen in mammalian ischemia/reperfusion studies. Insect models such as Drosophila melanogaster have additional advantages, such as short lifespans, low cost and well-described genetics. These models of anoxia tolerance share two common themes that enable survival without oxygen: entrance into a state of deep hypometabolism, and the suppression of cellular injury during anoxia and upon restoration of oxygen. The study of such models of anoxia tolerance, adapted through millions of years of evolution, may thus suggest protective pathways that could serve as therapeutic targets for diseases characterized by oxygen deprivation and ischemic/reperfusion injuries.
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Affiliation(s)
- Sarah L Milton
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA
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Verberk WCEP, Sommer U, Davidson RL, Viant MR. Anaerobic metabolism at thermal extremes: a metabolomic test of the oxygen limitation hypothesis in an aquatic insect. Integr Comp Biol 2013; 53:609-19. [PMID: 23604617 PMCID: PMC3776598 DOI: 10.1093/icb/ict015] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Thermal limits in ectotherms may arise through a mismatch between supply and demand of oxygen. At higher temperatures, the ability of their cardiac and ventilatory activities to supply oxygen becomes insufficient to meet their elevated oxygen demand. Consequently, higher levels of oxygen in the environment are predicted to enhance tolerance of heat, whereas reductions in oxygen are expected to reduce thermal limits. Here, we extend previous research on thermal limits and oxygen limitation in aquatic insect larvae and directly test the hypothesis of increased anaerobic metabolism and lower energy status at thermal extremes. We quantified metabolite profiles in stonefly nymphs under varying temperatures and oxygen levels. Under normoxia, the concept of oxygen limitation applies to the insects studied. Shifts in the metabolome of heat-stressed stonefly nymphs clearly indicate the onset of anaerobic metabolism (e.g., accumulation of lactate, acetate, and alanine), a perturbation of the tricarboxylic acid cycle (e.g., accumulation of succinate and malate), and a decrease in energy status (e.g., ATP), with corresponding decreases in their ability to survive heat stress. These shifts were more pronounced under hypoxic conditions, and negated by hyperoxia, which also improved heat tolerance. Perturbations of metabolic pathways in response to either heat stress or hypoxia were found to be somewhat similar but not identical. Under hypoxia, energy status was greatly compromised at thermal extremes, but energy shortage and anaerobic metabolism could not be conclusively identified as the sole cause underlying thermal limits under hyperoxia. Metabolomics proved useful for suggesting a range of possible mechanisms to explore in future investigations, such as the involvement of leaking membranes or free radicals. In doing so, metabolomics provided a more complete picture of changes in metabolism under hypoxia and heat stress.
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Affiliation(s)
- W C E P Verberk
- *Department of Animal Ecology and Ecophysiology, Institute of Water and Wetland Research, Radboud University Nijmegen, PO Box 9010, 6500 GL Nijmegen, The Netherlands; Marine Biology and Ecology Research Centre, University of Plymouth, Davy Building, Drake Circus, Plymouth PL4 8AA, UK; NERC Biomolecular Analysis Facility-Metabolomics Node (NBAF-B), School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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Ruka KA, Miller AP, Blumenthal EM. Inhibition of diuretic stimulation of an insect secretory epithelium by a cGMP-dependent protein kinase. Am J Physiol Renal Physiol 2013; 304:F1210-6. [PMID: 23445619 DOI: 10.1152/ajprenal.00231.2012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The rate of urine secretion by insect Malpighian tubules (MTs) is regulated by multiple diuretic and antidiuretic hormones, often working either synergistically or antagonistically. In the Drosophila melanogaster MT, only diuretic factors have been reported. Two such agents are the biogenic amine tyramine (TA) and the peptide drosokinin (DK), both of which act on the stellate cells of the tubule to increase transepithelial chloride conductance. In the current study, TA and DK signaling was quantified by microelectrode recording of the transepithelial potential in isolated Drosophila MTs. Treatment of tubules with cGMP caused a significant reduction in the depolarizing responses to both TA and DK, while cAMP had no effect on these responses. To determine whether a specific cGMP-dependent protein kinase (PKG) was mediating this inhibition, PKG expression was knocked down by RNAi in either the principal cells or the stellate cells. Knockdown of Pkg21D in the stellate cells eliminated the modulation of TA and DK signaling. Knockdown of Pkg21D with a second RNAi construct also reduced the modulation of TA signaling. In contrast, knockdown of the expression of foraging or CG4839, which encodes a known and a putative PKG, respectively, had no effect. These data indicate that cGMP, acting through the Pkg21D gene product in the stellate cells, can inhibit signaling by the diuretic agents TA and DK. This represents a novel function for cGMP and PKG in the Drosophila MT and suggests the existence of an antidiuretic hormone in Drosophila.
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Affiliation(s)
- Kristen A Ruka
- Dept. of Biological Sciences, Marquette Univ., P.O. Box 1881, Milwaukee, WI 53201-1881, USA
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37
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Caplan SL, Milton SL, Dawson-Scully K. A cGMP-dependent protein kinase (PKG) controls synaptic transmission tolerance to acute oxidative stress at the Drosophila larval neuromuscular junction. J Neurophysiol 2013; 109:649-58. [DOI: 10.1152/jn.00784.2011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Increasing evidence demonstrates that modulating the cGMP-dependent protein kinase G (PKG) pathway produces an array of behavioral phenotypes in the fruit fly, Drosophila melanogaster. Altering PKG activity, either genetically via the foraging ( for) gene or using pharmacology modifies tolerance to acute abiotic stresses such as hyperthermia and hypoxia. PKG signaling has been shown to modulate neuroprotection in many experimental paradigms of acute brain trauma and chronic neurodegenerative diseases. However, relatively little is known about how this stress-induced neuroprotective mechanism affects neural communication. In this study, we investigated the role PKG activity has on synaptic transmission at the Drosophila larval neuromuscular junction (NMJ) during acute oxidative stress and found that the application of 2.25 mM hydrogen peroxide (H2O2) disrupts synaptic function by rapidly increasing the rate of neuronal failure. Here, we report that reducing PKG activity through either natural genetic variation or an induced mutation of the for gene increases synaptic tolerance during acute oxidative conditions. Furthermore, pharmacological manipulations revealed that neurotransmission is significantly extended during acute H2O2 exposure upon inhibition of the PKG pathway. Conversely, activation of this signaling cascade using either genetics or pharmacology significantly reduced the time until synaptic failure. Therefore, these findings suggest a potential role for PKG activity to regulate the tolerance of synaptic transmission during acute oxidative stress, where inhibition promotes functional protection while activation increases susceptibility to neurotransmission breakdown.
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Affiliation(s)
- Stacee Lee Caplan
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida
| | - Sarah L. Milton
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida
| | - Ken Dawson-Scully
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, Florida
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Burns JG, Svetec N, Rowe L, Mery F, Dolan MJ, Boyce WT, Sokolowski MB. Gene-environment interplay in Drosophila melanogaster: chronic food deprivation in early life affects adult exploratory and fitness traits. Proc Natl Acad Sci U S A 2012; 109 Suppl 2:17239-44. [PMID: 23045644 PMCID: PMC3477394 DOI: 10.1073/pnas.1121265109] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Early life adversity has known impacts on adult health and behavior, yet little is known about the gene-environment interactions (GEIs) that underlie these consequences. We used the fruit fly Drosophila melanogaster to show that chronic early nutritional adversity interacts with rover and sitter allelic variants of foraging (for) to affect adult exploratory behavior, a phenotype that is critical for foraging, and reproductive fitness. Chronic nutritional adversity during adulthood did not affect rover or sitter adult exploratory behavior; however, early nutritional adversity in the larval period increased sitter but not rover adult exploratory behavior. Increasing for gene expression in the mushroom bodies, an important center of integration in the fly brain, changed the amount of exploratory behavior exhibited by sitter adults when they did not experience early nutritional adversity but had no effect in sitters that experienced early nutritional adversity. Manipulation of the larval nutritional environment also affected adult reproductive output of sitters but not rovers, indicating GEIs on fitness itself. The natural for variants are an excellent model to examine how GEIs underlie the biological embedding of early experience.
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Affiliation(s)
- James Geoffrey Burns
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada M5S 3B2
| | - Nicolas Svetec
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada M5S 3B2
| | - Locke Rowe
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada M5S 3B2
| | - Frederic Mery
- Laboratoire Évolution, Génomes, et Spéciation, Unité Propre de Recherche 9034, Centre National de la Recherche Scientifique, 91198 Gif sur Yvette, France
- Université Paris-Sud 11, 91405 Orsay, France; and
| | - Michael J. Dolan
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada M5S 3B2
| | - W. Thomas Boyce
- School of Population and Public Health and Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada V6T 1Z3
| | - Marla B. Sokolowski
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada M5S 3B2
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Verberk WC, Calosi P. Oxygen limits heat tolerance and drives heat hardening in the aquatic nymphs of the gill breathing damselfly Calopteryx virgo (Linnaeus, 1758). J Therm Biol 2012. [DOI: 10.1016/j.jtherbio.2012.01.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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41
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Hoback WW. Ecological and Experimental Exposure of Insects to Anoxia Reveals Surprising Tolerance. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2012. [DOI: 10.1007/978-94-007-1896-8_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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42
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Armstrong GAB, Xiao C, Krill JL, Seroude L, Dawson-Scully K, Robertson RM. Glial Hsp70 protects K+ homeostasis in the Drosophila brain during repetitive anoxic depolarization. PLoS One 2011; 6:e28994. [PMID: 22174942 PMCID: PMC3236231 DOI: 10.1371/journal.pone.0028994] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 11/17/2011] [Indexed: 01/04/2023] Open
Abstract
Neural tissue is particularly vulnerable to metabolic stress and loss of ion homeostasis. Repetitive stress generally leads to more permanent dysfunction but the mechanisms underlying this progression are poorly understood. We investigated the effects of energetic compromise in Drosophila by targeting the Na(+)/K(+)-ATPase. Acute ouabain treatment of intact flies resulted in subsequent repetitive comas that led to death and were associated with transient loss of K(+) homeostasis in the brain. Heat shock pre-conditioned flies were resistant to ouabain treatment. To control the timing of repeated loss of ion homeostasis we subjected flies to repetitive anoxia while recording extracellular [K(+)] in the brain. We show that targeted expression of the chaperone protein Hsp70 in glial cells delays a permanent loss of ion homeostasis associated with repetitive anoxic stress and suggest that this is a useful model for investigating molecular mechanisms of neuroprotection.
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43
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Charette M, Darveau CA, Perry SF, Rundle HD. Evolutionary consequences of altered atmospheric oxygen in Drosophila melanogaster. PLoS One 2011; 6:e26876. [PMID: 22046390 PMCID: PMC3203924 DOI: 10.1371/journal.pone.0026876] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2011] [Accepted: 10/05/2011] [Indexed: 11/18/2022] Open
Abstract
Twelve replicate populations of Drosophila melanogaster, all derived from a common ancestor, were independently evolved for 34+ generations in one of three treatment environments of varying PO(2): hypoxia (5.0-10.1 kPa), normoxia (21.3 kPa), and hyperoxia (40.5 kPa). Several traits related to whole animal performance and metabolism were assayed at various stages via "common garden" and reciprocal transplant assays to directly compare evolved and acclimatory differences among treatments. Results clearly demonstrate the evolution of a greater tolerance to acute hypoxia in the hypoxia-evolved populations, consistent with adaptation to this environment. Greater hypoxia tolerance was associated with an increase in citrate synthase activity in fly homogenate when compared to normoxic (control) populations, suggesting an increase in mitochondrial volume density in these populations. In contrast, no direct evidence of increased performance of the hyperoxia-evolved populations was detected, although a significant decrease in the tolerance of these populations to acute hypoxia suggests a cost to adaptation to hyperoxia. Hyperoxia-evolved populations had lower productivity overall (i.e., across treatment environments) and there was no evidence that hypoxia or hyperoxia-evolved populations had greatest productivity or longevity in their respective treatment environments, suggesting that these assays failed to capture the components of fitness relevant to adaptation.
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Affiliation(s)
- Marc Charette
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Steve F. Perry
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Howard D. Rundle
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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44
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Chen A, Kramer EF, Purpura L, Krill JL, Zars T, Dawson-Scully K. The influence of natural variation at the foraging gene on thermotolerance in adult Drosophila in a narrow temperature range. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:1113-8. [PMID: 21861180 DOI: 10.1007/s00359-011-0672-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Revised: 07/08/2011] [Accepted: 07/30/2011] [Indexed: 11/26/2022]
Abstract
Poikilothermic organisms such as insects have mechanisms to protect neural function under high temperature stress. Natural variation at the foraging (for) locus of the fruit fly, Drosophila melanogaster, encoding a cGMP-dependent protein kinase (PKG), influences neural thermotolerance in Drosophila larvae. The current study re-examines thermotolerance of adult flies to account for inconsistencies in the documented role of for during hyperthermia. We found that adult for (R) (rover) flies with high PKG activity were incapacitated faster under hyperthermic conditions of 39°C compared to their lower PKG activity counterparts for (s) and for (s2) (sitters), but not at higher temperatures. This indicates that lowered PKG activity promotes tolerance to heat stress, and that the for gene influences thermotolerance for a narrow range of temperatures in adult flies.
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Affiliation(s)
- Adam Chen
- Department of Biological Sciences, Florida Atlantic University, Boca Raton, FL 33431, USA
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