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Hines AD, Kewin AB, Van De Poll MN, Anggono V, Bademosi AT, van Swinderen B. Synapse-Specific Trapping of SNARE Machinery Proteins in the Anesthetized Drosophila Brain. J Neurosci 2024; 44:e0588232024. [PMID: 38749704 PMCID: PMC11170680 DOI: 10.1523/jneurosci.0588-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/01/2024] [Accepted: 05/06/2024] [Indexed: 05/18/2024] Open
Abstract
General anesthetics disrupt brain network dynamics through multiple pathways, in part through postsynaptic potentiation of inhibitory ion channels as well as presynaptic inhibition of neuroexocytosis. Common clinical general anesthetic drugs, such as propofol and isoflurane, have been shown to interact and interfere with core components of the exocytic release machinery to cause impaired neurotransmitter release. Recent studies however suggest that these drugs do not affect all synapse subtypes equally. We investigated the role of the presynaptic release machinery in multiple neurotransmitter systems under isoflurane general anesthesia in the adult female Drosophila brain using live-cell super-resolution microscopy and optogenetic readouts of exocytosis and neural excitability. We activated neurotransmitter-specific mushroom body output neurons and imaged presynaptic function under isoflurane anesthesia. We found that isoflurane impaired synaptic release and presynaptic protein dynamics in excitatory cholinergic synapses. In contrast, isoflurane had little to no effect on inhibitory GABAergic or glutamatergic synapses. These results present a distinct inhibitory mechanism for general anesthesia, whereby neuroexocytosis is selectively impaired at excitatory synapses, while inhibitory synapses remain functional. This suggests a presynaptic inhibitory mechanism that complements the other inhibitory effects of these drugs.
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Affiliation(s)
- Adam D Hines
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Amber B Kewin
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Matthew N Van De Poll
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Victor Anggono
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
- Clem Jones Centre for Ageing and Dementia Research, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Adekunle T Bademosi
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
- Clem Jones Centre for Ageing and Dementia Research, The University of Queensland, St Lucia 4072, Queensland, Australia
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, St Lucia 4072, Queensland, Australia
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Mashour GA. Anesthesia and the neurobiology of consciousness. Neuron 2024; 112:1553-1567. [PMID: 38579714 PMCID: PMC11098701 DOI: 10.1016/j.neuron.2024.03.002] [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: 02/02/2024] [Revised: 03/05/2024] [Accepted: 03/06/2024] [Indexed: 04/07/2024]
Abstract
In the 19th century, the discovery of general anesthesia revolutionized medical care. In the 21st century, anesthetics have become indispensable tools to study consciousness. Here, I review key aspects of the relationship between anesthesia and the neurobiology of consciousness, including interfaces of sleep and anesthetic mechanisms, anesthesia and primary sensory processing, the effects of anesthetics on large-scale functional brain networks, and mechanisms of arousal from anesthesia. I discuss the implications of the data derived from the anesthetized state for the science of consciousness and then conclude with outstanding questions, reflections, and future directions.
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Affiliation(s)
- George A Mashour
- Center for Consciousness Science, Department of Anesthesiology, Department of Pharmacology, Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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Woods CB, Predoi B, Howe M, Reczek CR, Kayser EB, Ramirez JM, Morgan PG, Sedensky MM. Potassium Leak Channels and Mitochondrial Complex I Interact in Glutamatergic Interneurons of the Mouse Spinal Cord. Anesthesiology 2024; 140:715-728. [PMID: 38147628 PMCID: PMC10939847 DOI: 10.1097/aln.0000000000004891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
BACKGROUND Volatile anesthetics induce hyperpolarizing potassium currents in spinal cord neurons that may contribute to their mechanism of action. They are induced at lower concentrations of isoflurane in noncholinergic neurons from mice carrying a loss-of-function mutation of the Ndufs4 gene, required for mitochondrial complex I function. The yeast NADH dehydrogenase enzyme, NDi1, can restore mitochondrial function in the absence of normal complex I activity, and gain-of-function Ndi1 transgenic mice are resistant to volatile anesthetics. The authors tested whether NDi1 would reduce the hyperpolarization caused by isoflurane in neurons from Ndufs4 and wild-type mice. Since volatile anesthetic behavioral hypersensitivity in Ndufs4 is transduced uniquely by glutamatergic neurons, it was also tested whether these currents were also unique to glutamatergic neurons in the Ndufs4 spinal cord. METHODS Spinal cord neurons from wild-type, NDi1, and Ndufs4 mice were patch clamped to characterize isoflurane sensitive currents. Neuron types were marked using fluorescent markers for cholinergic, glutamatergic, and γ-aminobutyric acid-mediated (GABAergic) neurons. Norfluoxetine was used to identify potassium channel type. Neuron type-specific Ndufs4 knockout animals were generated using type-specific Cre-recombinase with floxed Ndufs4. RESULTS Resting membrane potentials (RMPs) of neurons from NDi1;Ndufs4, unlike those from Ndufs4, were not hyperpolarized by 0.6% isoflurane (Ndufs4, ΔRMP -8.2 mV [-10 to -6.6]; P = 1.3e-07; Ndi1;Ndufs4, ΔRMP -2.1 mV [-7.6 to +1.4]; P = 1). Neurons from NDi1 animals in a wild-type background were not hyperpolarized by 1.8% isoflurane (wild-type, ΔRMP, -5.2 mV [-7.3 to -3.2]; P = 0.00057; Ndi1, ΔRMP, 0.6 mV [-1.7 to 3.2]; P = 0.68). In spinal cord slices from global Ndufs4 animals, holding currents (HC) were induced by 0.6% isoflurane in both GABAergic (ΔHC, 81.3 pA [61.7 to 101.4]; P = 2.6e-05) and glutamatergic (ΔHC, 101.2 pA [63.0 to 146.2]; P = 0.0076) neurons. In neuron type-specific Ndufs4 knockouts, HCs were increased in cholinergic (ΔHC, 119.5 pA [82.3 to 156.7]; P = 0.00019) and trended toward increase in glutamatergic (ΔHC, 85.5 pA [49 to 126.9]; P = 0.064) neurons but not in GABAergic neurons. CONCLUSIONS Bypassing complex I by overexpression of NDi1 eliminates increases in potassium currents induced by isoflurane in the spinal cord. The isoflurane-induced potassium currents in glutamatergic neurons represent a potential downstream mechanism of complex I inhibition in determining minimum alveolar concentration. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Christian B Woods
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101, USA
| | - Beatrice Predoi
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101, USA
| | - Miranda Howe
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101, USA
| | - Colleen R Reczek
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ernst-Bernhard Kayser
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101, USA
- Department of Neurological Surgery, University of Washington, Seattle, WA, 98105, USA
| | - Philip G Morgan
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle WA, 98105, USA
| | - Margaret M Sedensky
- Center for Integrative Brain Research, Seattle Children’s Research Institute, Seattle, WA, 98101, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle WA, 98105, USA
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Tanabe S, Lee H, Wang S, Hudetz AG. Spontaneous and Visual Stimulation Evoked Firing Sequences Are Distinct Under Desflurane Anesthesia. Neuroscience 2023; 528:54-63. [PMID: 37473851 DOI: 10.1016/j.neuroscience.2023.07.016] [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: 05/20/2023] [Revised: 07/09/2023] [Accepted: 07/12/2023] [Indexed: 07/22/2023]
Abstract
Recurring spike sequences are thought to underlie cortical computations and may be essential for information processing in the conscious state. How anesthesia at graded levels may influence spontaneous and stimulus-related spike sequences in visual cortex has not been fully elucidated. We recorded extracellular single-unit activity in the rat primary visual cortex in vivo during wakefulness and three levels of anesthesia produced by desflurane. The latencies of spike sequences within 0-200 ms from the onset of spontaneous UP states and visual flash-evoked responses were compared. During wakefulness, spike latency patterns linked to the local field potential theta cycle were similar to stimulus-evoked patterns. Under desflurane anesthesia, spontaneous UP state sequences differed from flash-evoked sequences due to the recruitment of low-firing excitatory neurons to the UP state. Flash-evoked spike sequences showed higher reliability and longer latency when stimuli were applied during DOWN states compared to UP states. At deeper levels, desflurane altered both UP state and flash-evoked spike sequences by selectively suppressing inhibitory neuron firing. The results reveal desflurane-induced complex changes in cortical firing sequences that may influence visual information processing.
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Affiliation(s)
- Sean Tanabe
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Heonsoo Lee
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Shiyong Wang
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48105, USA
| | - Anthony G Hudetz
- Center for Consciousness Science, Department of Anesthesiology, University of Michigan, Ann Arbor, MI 48105, USA.
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Hogarth K, Tarazi D, Maynes JT. The effects of general anesthetics on mitochondrial structure and function in the developing brain. Front Neurol 2023; 14:1179823. [PMID: 37533472 PMCID: PMC10390784 DOI: 10.3389/fneur.2023.1179823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Accepted: 06/28/2023] [Indexed: 08/04/2023] Open
Abstract
The use of general anesthetics in modern clinical practice is commonly regarded as safe for healthy individuals, but exposures at the extreme ends of the age spectrum have been linked to chronic cognitive impairments and persistent functional and structural alterations to the nervous system. The accumulation of evidence at both the epidemiological and experimental level prompted the addition of a warning label to inhaled anesthetics by the Food and Drug Administration cautioning their use in children under 3 years of age. Though the mechanism by which anesthetics may induce these detrimental changes remains to be fully elucidated, increasing evidence implicates mitochondria as a potential primary target of anesthetic damage, meditating many of the associated neurotoxic effects. Along with their commonly cited role in energy production via oxidative phosphorylation, mitochondria also play a central role in other critical cellular processes including calcium buffering, cell death pathways, and metabolite synthesis. In addition to meeting their immense energy demands, neurons are particularly dependent on the proper function and spatial organization of mitochondria to mediate specialized functions including neurotransmitter trafficking and release. Mitochondrial dependence is further highlighted in the developing brain, requiring spatiotemporally complex and metabolically expensive processes such as neurogenesis, synaptogenesis, and synaptic pruning, making the consequence of functional alterations potentially impactful. To this end, we explore and summarize the current mechanistic understanding of the effects of anesthetic exposure on mitochondria in the developing nervous system. We will specifically focus on the impact of anesthetic agents on mitochondrial dynamics, apoptosis, bioenergetics, stress pathways, and redox homeostasis. In addition, we will highlight critical knowledge gaps, pertinent challenges, and potential therapeutic targets warranting future exploration to guide mechanistic and outcomes research.
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Affiliation(s)
- Kaley Hogarth
- Program in Molecular Medicine, SickKids Research Institute, Toronto, ON, Canada
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Doorsa Tarazi
- Program in Molecular Medicine, SickKids Research Institute, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Jason T. Maynes
- Program in Molecular Medicine, SickKids Research Institute, Toronto, ON, Canada
- Department of Anesthesia and Pain Medicine, Hospital for Sick Children, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
- Department of Anesthesiology and Pain Medicine, University of Toronto, Toronto, ON, Canada
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6
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Perouansky M, Johnson-Schlitz D, Sedensky MM, Morgan PG. A primordial target: Mitochondria mediate both primary and collateral anesthetic effects of volatile anesthetics. Exp Biol Med (Maywood) 2023; 248:545-552. [PMID: 37208922 PMCID: PMC10350799 DOI: 10.1177/15353702231165025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023] Open
Abstract
One of the unsolved mysteries of medicine is how do volatile anesthetics (VAs) cause a patient to reversibly lose consciousness. In addition, identifying mechanisms for the collateral effects of VAs, including anesthetic-induced neurotoxicity (AiN) and anesthetic preconditioning (AP), has proven challenging. Multiple classes of molecules (lipids, proteins, and water) have been considered as potential VA targets, but recently proteins have received the most attention. Studies targeting neuronal receptors or ion channels had limited success in identifying the critical targets of VAs mediating either the phenotype of "anesthesia" or their collateral effects. Recent studies in both nematodes and fruit flies may provide a paradigm shift by suggesting that mitochondria may harbor the upstream molecular switch activating both primary and collateral effects. The disruption of a specific step of electron transfer within the mitochondrion causes hypersensitivity to VAs, from nematodes to Drosophila and to humans, while also modulating the sensitivity to collateral effects. The downstream effects from mitochondrial inhibition are potentially legion, but inhibition of presynaptic neurotransmitter cycling appears to be specifically sensitive to the mitochondrial effects. These findings are perhaps of even broader interest since two recent reports indicate that mitochondrial damage may well underlie neurotoxic and neuroprotective effects of VAs in the central nervous system (CNS). It is, therefore, important to understand how anesthetics interact with mitochondria to affect CNS function, not just for the desired facets of general anesthesia but also for significant collateral effects, both harmful and beneficial. A tantalizing possibility exists that both the primary (anesthesia) and secondary (AiN, AP) mechanisms may at least partially overlap in the mitochondrial electron transport chain (ETC).
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Affiliation(s)
- Misha Perouansky
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
- Laboratory of Genetics, School of Medicine and Public Health and College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Dena Johnson-Schlitz
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53792, USA
| | - Margaret M Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA 98101, USA
| | - Philip G Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington School of Medicine, Seattle, WA 98101, USA
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7
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Fedorov A, Lehto A, Klein J. Inhibition of mitochondrial respiration by general anesthetic drugs. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2023; 396:375-381. [PMID: 36385685 PMCID: PMC9832080 DOI: 10.1007/s00210-022-02338-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/10/2022] [Indexed: 11/18/2022]
Abstract
General anesthetic drugs have been associated with various unwanted effects including an interference with mitochondrial function. We had previously observed increases of lactate formation in the mouse brain during anesthesia with volatile anesthetic agents. In the present work, we used mitochondria that were freshly isolated from mouse brain to test mitochondrial respiration and ATP synthesis in the presence of six common anesthetic drugs. The volatile anesthetics isoflurane, halothane, and (to a lesser extent) sevoflurane caused an inhibition of complex I of the electron transport chain in a dose-dependent manner. Significant effects were seen at concentrations that are reached under clinical conditions (< 0.5 mM). Pentobarbital and propofol also inhibited complex I but at concentrations that were two-fold higher than clinical EC50 values. Only propofol caused an inhibition of complex II. Complex IV respiration was not affected by either agent. Ketamine did not affect mitochondrial respiration. Similarly, all anesthetic agents except ketamine suppressed ATP production at high concentrations. Only halothane increased cytochrome c release indicating damage of the mitochondrial membrane. In summary, volatile general anesthetic agents as well as pentobarbital and propofol dose-dependently inhibit mitochondrial respiration. This action may contribute to depressive actions of the drugs in the brain.
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Affiliation(s)
- Anton Fedorov
- Department of Pharmacology and Clinical Pharmacy, College of Pharmacy, Goethe University Frankfurt, Max-Von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Alina Lehto
- Department of Pharmacology and Clinical Pharmacy, College of Pharmacy, Goethe University Frankfurt, Max-Von-Laue-Str. 9, 60438 Frankfurt, Germany
| | - Jochen Klein
- Department of Pharmacology and Clinical Pharmacy, College of Pharmacy, Goethe University Frankfurt, Max-Von-Laue-Str. 9, 60438 Frankfurt, Germany
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8
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Anesthesia: Synaptic power failure. Curr Biol 2022; 32:R781-R783. [PMID: 35882199 DOI: 10.1016/j.cub.2022.06.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
One of the greatest unresolved mysteries in medicine relates to the molecular and neuronal mechanisms through which general anesthetics abolish perception. A new study in mice with mutations affecting mitochondrial complex 1 suggests that anesthetic-disruption of cellular energetics impairs endocytosis to alter synaptic function.
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9
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Jung S, Zimin PI, Woods CB, Kayser EB, Haddad D, Reczek CR, Nakamura K, Ramirez JM, Sedensky MM, Morgan PG. Isoflurane inhibition of endocytosis is an anesthetic mechanism of action. Curr Biol 2022; 32:3016-3032.e3. [PMID: 35688155 PMCID: PMC9329204 DOI: 10.1016/j.cub.2022.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 03/30/2022] [Accepted: 05/13/2022] [Indexed: 10/18/2022]
Abstract
The mechanisms of volatile anesthetic action remain among the most perplexing mysteries of medicine. Across phylogeny, volatile anesthetics selectively inhibit mitochondrial complex I, and they also depress presynaptic excitatory signaling. To explore how these effects are linked, we studied isoflurane effects on presynaptic vesicle cycling and ATP levels in hippocampal cultured neurons from wild-type and complex I mutant (Ndufs4(KO)) mice. To bypass complex I, we measured isoflurane effects on anesthetic sensitivity in mice expressing NADH dehydrogenase (NDi1). Endocytosis in physiologic concentrations of glucose was delayed by effective behavioral concentrations of isoflurane in both wild-type (τ [unexposed] 44.8 ± 24.2 s; τ [exposed] 116.1 ± 28.1 s; p < 0.01) and Ndufs4(KO) cultures (τ [unexposed] 67.6 ± 16.0 s; τ [exposed] 128.4 ± 42.9 s; p = 0.028). Increasing glucose, to enhance glycolysis and increase ATP production, led to maintenance of both ATP levels and endocytosis (τ [unexposed] 28.0 ± 14.4; τ [exposed] 38.2 ± 5.7; reducing glucose worsened ATP levels and depressed endocytosis (τ [unexposed] 85.4 ± 69.3; τ [exposed] > 1,000; p < 0.001). The block in recycling occurred at the level of reuptake of synaptic vesicles into the presynaptic cell. Expression of NDi1 in wild-type mice caused behavioral resistance to isoflurane for tail clamp response (EC50 Ndi1(-) 1.27% ± 0.14%; Ndi1(+) 1.55% ± 0.13%) and halothane (EC50 Ndi1(-) 1.20% ± 0.11%; Ndi1(+) 1.46% ± 0.10%); expression of NDi1 in neurons improved hippocampal function, alleviated inhibition of presynaptic recycling, and increased ATP levels during isoflurane exposure. The clear alignment of cell culture data to in vivo phenotypes of both isoflurane-sensitive and -resistant mice indicates that inhibition of mitochondrial complex I is a primary mechanism of action of volatile anesthetics.
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Affiliation(s)
- Sangwook Jung
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Pavel I Zimin
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA
| | - Christian B Woods
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Ernst-Bernhard Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Dominik Haddad
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA
| | - Colleen R Reczek
- Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Ken Nakamura
- Gladstone Institute of Neurological Disease, San Francisco, CA 94158, USA; Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Jan-Marino Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Neurological Surgery, University of Washington, Seattle, WA 98105, USA
| | - Margaret M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA
| | - Philip G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195, USA.
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10
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van de Wal MAE, Adjobo-Hermans MJW, Keijer J, Schirris TJJ, Homberg JR, Wieckowski MR, Grefte S, van Schothorst EM, van Karnebeek C, Quintana A, Koopman WJH. Ndufs4 knockout mouse models of Leigh syndrome: pathophysiology and intervention. Brain 2022. [PMID: 34849584 DOI: 10.1093/brain/awab426%jbrain] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Mitochondria are small cellular constituents that generate cellular energy (ATP) by oxidative phosphorylation (OXPHOS). Dysfunction of these organelles is linked to a heterogeneous group of multisystemic disorders, including diabetes, cancer, ageing-related pathologies and rare mitochondrial diseases. With respect to the latter, mutations in subunit-encoding genes and assembly factors of the first OXPHOS complex (complex I) induce isolated complex I deficiency and Leigh syndrome. This syndrome is an early-onset, often fatal, encephalopathy with a variable clinical presentation and poor prognosis due to the lack of effective intervention strategies. Mutations in the nuclear DNA-encoded NDUFS4 gene, encoding the NADH:ubiquinone oxidoreductase subunit S4 (NDUFS4) of complex I, induce 'mitochondrial complex I deficiency, nuclear type 1' (MC1DN1) and Leigh syndrome in paediatric patients. A variety of (tissue-specific) Ndufs4 knockout mouse models were developed to study the Leigh syndrome pathomechanism and intervention testing. Here, we review and discuss the role of complex I and NDUFS4 mutations in human mitochondrial disease, and review how the analysis of Ndufs4 knockout mouse models has generated new insights into the MC1ND1/Leigh syndrome pathomechanism and its therapeutic targeting.
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Affiliation(s)
- Melissa A E van de Wal
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | | | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Tom J J Schirris
- Department of Pharmacology and Toxicology, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Judith R Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Sander Grefte
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | | | - Clara van Karnebeek
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
- Department of Pediatrics, Emma Personalized Medicine Center, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Department of Human Genetics, Emma Personalized Medicine Center, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Albert Quintana
- Mitochondrial Neuropathology Laboratory, Institut de Neurociències and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Werner J H Koopman
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
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11
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van de Wal M, Adjobo-Hermans M, Keijer J, Schirris T, Homberg J, Wieckowski MR, Grefte S, van Schothorst EM, van Karnebeek C, Quintana A, Koopman WJH. Ndufs4 knockout mouse models of Leigh syndrome: pathophysiology and intervention. Brain 2021; 145:45-63. [PMID: 34849584 PMCID: PMC8967107 DOI: 10.1093/brain/awab426] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/25/2021] [Accepted: 11/11/2021] [Indexed: 11/14/2022] Open
Abstract
Mitochondria are small cellular constituents that generate cellular energy (ATP) by oxidative phosphorylation (OXPHOS). Dysfunction of these organelles is linked to a heterogeneous group of multisystemic disorders, including diabetes, cancer, ageing-related pathologies and rare mitochondrial diseases. With respect to the latter, mutations in subunit-encoding genes and assembly factors of the first OXPHOS complex (complex I) induce isolated complex I deficiency and Leigh syndrome. This syndrome is an early-onset, often fatal, encephalopathy with a variable clinical presentation and poor prognosis due to the lack of effective intervention strategies. Mutations in the nuclear DNA-encoded NDUFS4 gene, encoding the NADH:ubiquinone oxidoreductase subunit S4 (NDUFS4) of complex I, induce ‘mitochondrial complex I deficiency, nuclear type 1’ (MC1DN1) and Leigh syndrome in paediatric patients. A variety of (tissue-specific) Ndufs4 knockout mouse models were developed to study the Leigh syndrome pathomechanism and intervention testing. Here, we review and discuss the role of complex I and NDUFS4 mutations in human mitochondrial disease, and review how the analysis of Ndufs4 knockout mouse models has generated new insights into the MC1ND1/Leigh syndrome pathomechanism and its therapeutic targeting.
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Affiliation(s)
- Melissa van de Wal
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Merel Adjobo-Hermans
- Department of Biochemistry (286), RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Tom Schirris
- Department of Pharmacology and Toxicology, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands
| | - Judith Homberg
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Mariusz R Wieckowski
- Laboratory of Mitochondrial Biology and Metabolism, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Sander Grefte
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | | | - Clara van Karnebeek
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands.,Department of Pediatrics, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Albert Quintana
- Mitochondrial Neuropathology Laboratory, Institut de Neurociències and Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Werner J H Koopman
- Department of Pediatrics, Amalia Children's Hospital, RIMLS, RCMM, Radboudumc, Nijmegen, The Netherlands.,Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
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12
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Mitochondrial Function and Anesthetic Sensitivity in the Mouse Spinal Cord. Anesthesiology 2021; 134:901-914. [PMID: 33909880 DOI: 10.1097/aln.0000000000003794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Ndufs4 knockout (KO) mice are defective in mitochondrial complex I function and hypersensitive to inhibition of spinal cord-mediated response to noxious stimuli by volatile anesthetics. It was hypothesized that, compared to wild-type, synaptic or intrinsic neuronal function is hypersensitive to isoflurane in spinal cord slices from knockout mice. METHODS Neurons from slices of the vestibular nucleus, central medial thalamus, and spinal cord from wild-type and the global Ndufs4 knockout were patch clamped. Unstimulated synaptic and intrinsic neuronal characteristics were measured in response to isoflurane. Norfluoxetine was used to block TREK channel conductance. Cholinergic cells were labeled with tdTomato. RESULTS All values are reported as means and 95% CIs. Spontaneous synaptic activities were not different between the mutant and control. Isoflurane (0.6%; 0.25 mM; Ndufs4[KO] EC95) increased the holding current in knockout (ΔHolding current, 126 pA [95% CI, 99 to 152 pA]; ΔHolding current P < 0.001; n = 21) but not wild-type (ΔHolding current, 2 7 pA [95% CI, 9 to 47 pA]; ΔHolding current, P = 0.030; n = 25) spinal cord slices. Knockout and wild-type ΔHolding currents were significantly different (P < 0.001). Changes comparable to those in the knockout were seen in the wild type only in 1.8% (0.74 mM) isoflurane (ΔHolding current, 72 pA [95% CI, 43 to 97 pA]; ΔHolding current, P < 0.001; n = 13), the control EC95. Blockade of action potentials indicated that the increased holding current in the knockout was not dependent on synaptic input (ΔHolding current, 154 pA [95% CI, 99 to 232 pA]; ΔHolding current, P = 0.506 compared to knockout without blockade; n = 6). Noncholinergic neurons mediated the increase in holding current sensitivity in Ndufs4 knockout. The increased currents were blocked by norfluoxetine. CONCLUSIONS Isoflurane increased an outwardly rectifying potassium current in ventral horn neurons of the Ndufs4(KO) mouse at a concentration much lower than in controls. Noncholinergic neurons in the spinal cord ventral horn mediated the effect. Presynaptic functions in Ndufs4(KO) slices were not hypersensitive to isoflurane. These data link anesthetic sensitivity, mitochondrial function, and postsynaptic channel activity. EDITOR’S PERSPECTIVE
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13
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Chen Y, Zhang J. How Energy Supports Our Brain to Yield Consciousness: Insights From Neuroimaging Based on the Neuroenergetics Hypothesis. Front Syst Neurosci 2021; 15:648860. [PMID: 34295226 PMCID: PMC8291083 DOI: 10.3389/fnsys.2021.648860] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Accepted: 05/26/2021] [Indexed: 11/13/2022] Open
Abstract
Consciousness is considered a result of specific neuronal processes and mechanisms in the brain. Various suggested neuronal mechanisms, including the information integration theory (IIT), global neuronal workspace theory (GNWS), and neuronal construction of time and space as in the context of the temporospatial theory of consciousness (TTC), have been laid forth. However, despite their focus on different neuronal mechanisms, these theories neglect the energetic-metabolic basis of the neuronal mechanisms that are supposed to yield consciousness. Based on the findings of physiology-induced (sleep), pharmacology-induced (general anesthesia), and pathology-induced [vegetative state/unresponsive wakeful syndrome (VS/UWS)] loss of consciousness in both human subjects and animals, we, in this study, suggest that the energetic-metabolic processes focusing on ATP, glucose, and γ-aminobutyrate/glutamate are indispensable for functional connectivity (FC) of normal brain networks that renders consciousness possible. Therefore, we describe the energetic-metabolic predispositions of consciousness (EPC) that complement the current theories focused on the neural correlates of consciousness (NCC).
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Affiliation(s)
- Yali Chen
- Department of Anesthesiology, Fudan University Shanghai Cancer Center, Shanghai, China
| | - Jun Zhang
- Department of Anesthesiology, Fudan University Shanghai Cancer Center, Shanghai, China.,Department of Oncology, Shanghai Medical college, Fudan University, Shanghai, China
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14
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Hsieh VC, Niezgoda J, Sedensky MM, Hoppel CL, Morgan PG. Anesthetic Hypersensitivity in a Case-Controlled Series of Patients With Mitochondrial Disease. Anesth Analg 2021; 133:924-932. [PMID: 33591116 DOI: 10.1213/ane.0000000000005430] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Children with mitochondrial disease undergo anesthesia for a wide array of surgical procedures. However, multiple medications used for their perioperative care can affect mitochondrial function. Defects in function of the mitochondrial electron transport chain (ETC) can lead to a profound hypersensitivity to sevoflurane in children. We studied the sensitivities to sevoflurane, during mask induction and maintenance of general anesthesia, in children presenting for muscle biopsies for diagnosis of mitochondrial disease. METHODS In this multicenter study, 91 children, aged 6 months to 16 years, presented to the operating room for diagnostic muscle biopsy for presumptive mitochondrial disease. General anesthesia was induced by a slow increase of inhaled sevoflurane concentration. The primary end point, end-tidal (ET) sevoflurane necessary to achieve a bispectral index (BIS) of 60, was recorded. Secondary end points were maximal sevoflurane used to maintain a BIS between 40 and 60 during the case, and maximum and minimum heart rate and blood pressures. After induction, general anesthesia was maintained according to the preferences of the providers directing the cases. Primary data were analyzed comparing data from patients with complex I deficiencies to other groups using nonparametric statistics in SPSS v.27. RESULTS The median sevoflurane concentration to reach BIS of 60 during inductions (ET sevoflurane % [BIS = 60]) was significantly lower for patients with complex I defects (0.98%; 95% confidence interval [CI], 0.5-1.4) compared to complex II (1.95%; 95% CI, 1.2-2.7; P < .001), complex III (2.0%; 95% CI, 0.7-3.5; P < .001), complex IV (2.0%; 95% CI, 1.7-3.2; P < .001), and normal groups (2.2%; 95% CI, 1.8-3.0; P < .001). The sevoflurane sensitivities of complex I patients did not reach significance when compared to patients diagnosed with mitochondrial disease but without an identifiable ETC abnormality (P = .172). Correlation of complex I activity with ET sevoflurane % (BIS = 60) gave a Spearman's coefficient of 0.505 (P < .001). The differences in sensitivities between groups were less during the maintenance of the anesthetic than during induction. CONCLUSIONS The data indicate that patients with complex I dysfunction are hypersensitive to sevoflurane compared to normal patients. Hypersensitivity was less common in patients presenting with other mitochondrial defects or without a mitochondrial diagnosis.
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Affiliation(s)
- Vincent C Hsieh
- From the Department of Anesthesiology and Perioperative Medicine, University of Washington and Seattle Children's Hospital, Seattle, Washington
| | - Julie Niezgoda
- Department of Pediatric Anesthesiology, Cleveland Clinic, Cleveland, Ohio
| | - Margaret M Sedensky
- From the Department of Anesthesiology and Perioperative Medicine, University of Washington and Seattle Children's Hospital, Seattle, Washington
| | - Charles L Hoppel
- Department of Pharmacology and Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Philip G Morgan
- From the Department of Anesthesiology and Perioperative Medicine, University of Washington and Seattle Children's Hospital, Seattle, Washington
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15
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Miller HC, Louw R, Mereis M, Venter G, Boshoff JD, Mienie L, van Reenen M, Venter M, Lindeque JZ, Domínguez-Martínez A, Quintana A, van der Westhuizen FH. Metallothionein 1 Overexpression Does Not Protect Against Mitochondrial Disease Pathology in Ndufs4 Knockout Mice. Mol Neurobiol 2021; 58:243-262. [PMID: 32918239 DOI: 10.1007/s12035-020-02121-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/05/2020] [Indexed: 01/24/2023]
Abstract
Mitochondrial diseases (MD), such as Leigh syndrome (LS), present with severe neurological and muscular phenotypes in patients, but have no known cure and limited treatment options. Based on their neuroprotective effects against other neurodegenerative diseases in vivo and their positive impact as an antioxidant against complex I deficiency in vitro, we investigated the potential protective effect of metallothioneins (MTs) in an Ndufs4 knockout mouse model (with a very similar phenotype to LS) crossed with an Mt1 overexpressing mouse model (TgMt1). Despite subtle reductions in the expression of neuroinflammatory markers GFAP and IBA1 in the vestibular nucleus and hippocampus, we found no improvement in survival, growth, locomotor activity, balance, or motor coordination in the Mt1 overexpressing Ndufs4-/- mice. Furthermore, at a cellular level, no differences were detected in the metabolomics profile or gene expression of selected one-carbon metabolism and oxidative stress genes, performed in the brain and quadriceps, nor in the ROS levels of macrophages derived from these mice. Considering these outcomes, we conclude that MT1, in general, does not protect against the impaired motor activity or improve survival in these complex I-deficient mice. The unexpected absence of increased oxidative stress and metabolic redox imbalance in this MD model may explain these observations. However, tissue-specific observations such as the mildly reduced inflammation in the hippocampus and vestibular nucleus, as well as differential MT1 expression in these tissues, may yet reveal a tissue- or cell-specific role for MTs in these mice.
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Affiliation(s)
- Hayley Christy Miller
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Roan Louw
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Michelle Mereis
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Gerda Venter
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - John-Drew Boshoff
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Liesel Mienie
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Mari van Reenen
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Marianne Venter
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Jeremie Zander Lindeque
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa
| | - Adán Domínguez-Martínez
- Institut de Neurociències i Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Albert Quintana
- Institut de Neurociències i Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Francois Hendrikus van der Westhuizen
- Human Metabolomics, Faculty of Natural and Agricultural Sciences, North-West University (Potchefstroom Campus), Private Bag X6001, Potchefstroom, South Africa.
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16
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Gong C, Zhang D, Ou W, Ou M, Liang P, Liao D, Zhang W, Zhu T, Liu J, Zhou C. Deficiency of Mitochondrial Functions and Peroxidation of Frontoparietal Cortex Enhance Isoflurane Sensitivity in Aging Mice. Front Aging Neurosci 2020; 12:583542. [PMID: 33343330 PMCID: PMC7744615 DOI: 10.3389/fnagi.2020.583542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 11/09/2020] [Indexed: 02/05/2023] Open
Abstract
Background: Hypersensitivity to general anesthetics may predict poor postoperative outcomes, especially among the older subjects. Therefore, it is essential to elucidate the mechanism underlying hypersensitivity to volatile anesthetics in the aging population. Given the fact that isoflurane sensitivity increases with aging, we hypothesized that deficiencies of mitochondrial function and elevated oxidative levels in the frontoparietal cortex may contribute to the enhanced sensitivity to isoflurane in aging mice. Methods: Isoflurane sensitivity in aging mice was determined by the concentration of isoflurane that is required for loss of righting reflex (LORR). Mitochondrial bioenergetics of the frontoparietal cortex was measured using a Seahorse XFp analyzer. Protein oxidation and lipid oxidation in the frontoparietal cortex were assessed using the Oxyblot protein oxidation detection kit and thiobarbituric acid reactive substance (TBARS) assay, respectively. Contributions of mitochondrial complex II inhibition by malonate and peroxidation by ozone to isoflurane sensitivity were tested in vivo. Besides, effects of antioxidative therapy on mitochondrial function and isoflurane sensitivity in mice were also measured. Results: The mean concentration of isoflurane that is required for LORR in aging mice (14-16 months old) was 0.83% ± 0.13% (mean ± SD, n = 80). Then, the mice were divided into three groups as sensitive group (S group, mean - SD), medium group (M group), and resistant group (R group, mean + SD) based on individual concentrations of isoflurane required for LORR. Activities of mitochondrial complex II and complex IV in mice of the S group were significantly lower than those of the R group, while frontoparietal cortical malondialdehyde (MDA) levels were higher in the mice of S group. Both inhibition of mitochondrial complexes and peroxidation significantly decreased the concentration of isoflurane that is required for LORR in vivo. After treatment with idebenone, the levels of lipid oxidation were alleviated and mitochondrial function was restored in aging mice. The concentration of isoflurane that required for LORR was also elevated after idebenone treatment. Conclusions: Decreased mitochondrial functions and higher oxidative stress levels in the frontoparietal cortex may contribute to the hypersensitivity to isoflurane in aging mice.
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Affiliation(s)
- Cansheng Gong
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Donghang Zhang
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Wei Ou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Mengchan Ou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Peng Liang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Daqing Liao
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China
| | - Weiyi Zhang
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Tao Zhu
- Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Jin Liu
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
| | - Cheng Zhou
- Laboratory of Anesthesia & Critical Care Medicine, Translational Neuroscience Center, National Clinical Research Center for Geriatrics, West China Hospital of Sichuan University, Chengdu, China.,Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, China
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17
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Johnson SC, Kayser EB, Bornstein R, Stokes J, Bitto A, Park KY, Pan A, Sun G, Raftery D, Kaeberlein M, Sedensky MM, Morgan PG. Regional metabolic signatures in the Ndufs4(KO) mouse brain implicate defective glutamate/α-ketoglutarate metabolism in mitochondrial disease. Mol Genet Metab 2020; 130:118-132. [PMID: 32331968 PMCID: PMC7272141 DOI: 10.1016/j.ymgme.2020.03.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 03/29/2020] [Indexed: 02/08/2023]
Abstract
Leigh Syndrome (LS) is a mitochondrial disorder defined by progressive focal neurodegenerative lesions in specific regions of the brain. Defects in NDUFS4, a subunit of complex I of the mitochondrial electron transport chain, cause LS in humans; the Ndufs4 knockout mouse (Ndufs4(KO)) closely resembles the human disease. Here, we probed brain region-specific molecular signatures in pre-symptomatic Ndufs4(KO) to identify factors which underlie focal neurodegeneration. Metabolomics revealed that free amino acid concentrations are broadly different by region, and glucose metabolites are increased in a manner dependent on both region and genotype. We then tested the impact of the mTOR inhibitor rapamycin, which dramatically attenuates LS in Ndufs4(KO), on region specific metabolism. Our data revealed that loss of Ndufs4 drives pathogenic changes to CNS glutamine/glutamate/α-ketoglutarate metabolism which are rescued by mTOR inhibition Finally, restriction of the Ndufs4 deletion to pre-synaptic glutamatergic neurons recapitulated the whole-body knockout. Together, our findings are consistent with mTOR inhibition alleviating disease by increasing availability of α-ketoglutarate, which is both an efficient mitochondrial complex I substrate in Ndufs4(KO) and an important metabolite related to neurotransmitter metabolism in glutamatergic neurons.
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Affiliation(s)
- Simon C Johnson
- Department of Neurology, University of Washington, Seattle, WA 98105, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Ernst-Bernhard Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Rebecca Bornstein
- Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Julia Stokes
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA
| | - Alessandro Bitto
- Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Kyung Yeon Park
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Amanda Pan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Grace Sun
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Daniel Raftery
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Department of Chemistry, University of Washington, Seattle, WA 98109, United States
| | - Matt Kaeberlein
- Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Margaret M Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Philip G Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98105, USA; Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA 98101, USA.
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18
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Anesthetics Have Different Effects on the Electrocorticographic Spectra of Wild-type and Mitochondrial Mutant Mice. Anesthesiology 2019; 129:744-755. [PMID: 30074932 DOI: 10.1097/aln.0000000000002368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
WHAT WE ALREADY KNOW ABOUT THIS TOPIC WHAT THIS ARTICLE TELLS US THAT IS NEW: BACKGROUND:: Knockout of the mitochondrial protein Ndufs4 (Ndufs4[KO]) in mice causes hypersensitivity to volatile anesthetics but resistance to ketamine. The authors hypothesized that electrocorticographic changes underlying the responses of Ndufs4(KO) to volatile anesthetics and to ketamine would be similar in mutant and control mice. METHODS Electrocorticographic recordings at equipotent volatile anesthetic concentrations were compared between genotypes. In separate studies, control and cell type-specific Ndufs4(KO) mice were anesthetized with intraperitoneal ketamine to determine their ED50s. RESULTS Ndufs4 (KO) did not differ from controls in baseline electrocorticography (N = 5). Compared to baseline, controls exposed to isoflurane (EC50) lost power (expressed as mean baseline [µV/Hz]; mean isoflurane [µV/Hz]) in delta (2.45; 0.50), theta (1.41; 0.16), alpha (0.23; 0.05), beta (0.066; 0.016), and gamma (0.020; 0.005) frequency bands (N = 5). Compared to baseline, at their isoflurane EC50, Ndufs4(KO) maintained power in delta (1.08; 1.38), theta (0.36; 0.26), and alpha (0.09; 0.069) frequency bands but decreased in beta (0.041; 0.023) and gamma (0.020; 0.0068) frequency bands (N = 5). Similar results were seen for both genotypes in halothane. Vesicular glutamate transporter 2 (VGLUT2)-specific Ndufs4(KO) mice were markedly resistant to ketamine (ED50; 125 mg/kg) compared to control mice (ED50; 75 mg/kg; N = 6). At their respective ED95s for ketamine, mutant (N = 5) electrocorticography spectra showed a decrease in power in the beta (0.040; 0.020) and gamma (0.035; 0.015) frequency bands not seen in controls (N = 7). CONCLUSIONS Significant differences exist between the electrocorticographies of mutant and control mice at equipotent doses for volatile anesthetics and ketamine. The energetic state specifically of excitatory neurons determines the behavioral response to ketamine.
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19
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Bolea I, Gella A, Sanz E, Prada-Dacasa P, Menardy F, Bard AM, Machuca-Márquez P, Eraso-Pichot A, Mòdol-Caballero G, Navarro X, Kalume F, Quintana A. Defined neuronal populations drive fatal phenotype in a mouse model of Leigh syndrome. eLife 2019; 8:e47163. [PMID: 31403401 PMCID: PMC6731060 DOI: 10.7554/elife.47163] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/11/2019] [Indexed: 12/12/2022] Open
Abstract
Mitochondrial deficits in energy production cause untreatable and fatal pathologies known as mitochondrial disease (MD). Central nervous system affectation is critical in Leigh Syndrome (LS), a common MD presentation, leading to motor and respiratory deficits, seizures and premature death. However, only specific neuronal populations are affected. Furthermore, their molecular identity and their contribution to the disease remains unknown. Here, using a mouse model of LS lacking the mitochondrial complex I subunit Ndufs4, we dissect the critical role of genetically-defined neuronal populations in LS progression. Ndufs4 inactivation in Vglut2-expressing glutamatergic neurons leads to decreased neuronal firing, brainstem inflammation, motor and respiratory deficits, and early death. In contrast, Ndufs4 deletion in GABAergic neurons causes basal ganglia inflammation without motor or respiratory involvement, but accompanied by hypothermia and severe epileptic seizures preceding death. These results provide novel insight in the cell type-specific contribution to the pathology, dissecting the underlying cellular mechanisms of MD.
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Affiliation(s)
- Irene Bolea
- Center for Developmental Therapeutics, Seattle Children’s Research InstituteSeattleUnited States
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
| | - Alejandro Gella
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
- Department of Biochemistry and Molecular BiologyUniversitat Autònoma de BarcelonaBellaterraSpain
| | - Elisenda Sanz
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
- Department of Cell Biology, Physiology and ImmunologyUniversitat Autònoma de BarcelonaBellaterraSpain
| | - Patricia Prada-Dacasa
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
- Department of Cell Biology, Physiology and ImmunologyUniversitat Autònoma de BarcelonaBellaterraSpain
| | - Fabien Menardy
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
| | - Angela M Bard
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
| | | | - Abel Eraso-Pichot
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
| | - Guillem Mòdol-Caballero
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
- Department of Cell Biology, Physiology and ImmunologyUniversitat Autònoma de BarcelonaBellaterraSpain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)BellaterraSpain
| | - Xavier Navarro
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
- Department of Cell Biology, Physiology and ImmunologyUniversitat Autònoma de BarcelonaBellaterraSpain
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED)BellaterraSpain
| | - Franck Kalume
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
- Department of Neurological SurgeryUniversity of WashingtonSeattleUnited States
- Department of PharmacologyUniversity of WashingtonSeattleUnited States
| | - Albert Quintana
- Center for Developmental Therapeutics, Seattle Children’s Research InstituteSeattleUnited States
- Institut de Neurociències, Universitat Autònoma de BarcelonaBellaterraSpain
- Center for Integrative Brain Research, Seattle Children’s Research InstituteSeattleUnited States
- Department of Cell Biology, Physiology and ImmunologyUniversitat Autònoma de BarcelonaBellaterraSpain
- Department of PediatricsUniversity of WashingtonSeattleUnited States
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20
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Koyanagi Y, Torturo CL, Cook DC, Zhou Z, Hemmings HC. Role of specific presynaptic calcium channel subtypes in isoflurane inhibition of synaptic vesicle exocytosis in rat hippocampal neurones. Br J Anaesth 2019; 123:219-227. [PMID: 31056238 PMCID: PMC6676046 DOI: 10.1016/j.bja.2019.03.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 02/24/2019] [Accepted: 03/16/2019] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND P/Q- and N-type voltage-gated calcium channels (VGCC) are the principal subtypes mediating synaptic vesicle (SV) exocytosis. Both the degree of isoflurane inhibition of SV exocytosis and VGCC subtype expression vary between brain regions and neurotransmitter phenotype. We hypothesised that differences in VGCC subtype expression contribute to synapse-selective presynaptic effects of isoflurane. METHODS We used quantitative live-cell imaging to measure exocytosis in cultured rat hippocampal neurones after transfection of the fluorescent biosensor vGlut1-pHluorin. Selective inhibitors of P/Q- and N-type VGCCs were used to isolate subtype-specific effects of isoflurane. RESULTS Inhibition of N-type channels by 1 μM ω-conotoxin GVIA reduced SV exocytosis to 81±5% of control (n=10). Residual exocytosis mediated by P/Q-type channels was further inhibited by isoflurane to 42±4% of control (n=10). The P/Q-type channel inhibitor ω-agatoxin IVA at 0.4 μM inhibited SV exocytosis to 29±3% of control (n=10). Residual exocytosis mediated by N-type channels was further inhibited by isoflurane to 17±3% of control (n=10). Analysis of isoflurane effects at the level of individual boutons revealed no difference in sensitivity to isoflurane between P/Q- or N-type channel-mediated SV exocytosis (P=0.35). There was no correlation between the effect of agatoxin (P=0.91) or conotoxin (P=0.15) and the effect of isoflurane on exocytosis. CONCLUSIONS Sensitivity of SV exocytosis to isoflurane in rat hippocampal neurones is independent of the specific VGCC subtype coupled to exocytosis. The differential sensitivity of VGCC subtypes to isoflurane does not explain the observed neurotransmitter-selective effects of isoflurane in hippocampus.
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Affiliation(s)
- Yuko Koyanagi
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA; Department of Anesthesiology, Nihon University School of Dentistry, Tokyo, Japan
| | | | - Daniel C Cook
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Zhenyu Zhou
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Hugh C Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA; Department of Pharmacology, Weill Cornell Medicine, New York, NY, USA.
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Ramadasan-Nair R, Hui J, Itsara LS, Morgan PG, Sedensky MM. Mitochondrial Function in Astrocytes Is Essential for Normal Emergence from Anesthesia in Mice. Anesthesiology 2019; 130:423-434. [PMID: 30707122 PMCID: PMC6375739 DOI: 10.1097/aln.0000000000002528] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
WHAT WE ALREADY KNOW ABOUT THIS TOPIC In mice, restriction of loss of the mitochondrial complex I gene Ndufs4 to glutamatergic neurons confers a profound hypersensitivity to volatile anesthetics.Astrocytes are crucial to glutamatergic synapse functioning during excitatory transmission. WHAT THIS ARTICLE TELLS US THAT IS NEW In a tamoxifen-activated astrocyte-specific Ndufs4(KO) mouse, the induction EC50s for tail clamp in both isoflurane and halothane were similar between the control and astrocyte-specific Ndufs4(KO) mice at 3 weeks after 4-hydroxy tamoxifen injection. However, the emergent concentrations in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were half that of the controls.Similarly, the induction EC50s for loss of righting reflex were similar between the control and astrocyte-specific Ndufs4(KO) mice; concentrations for regain of righting reflex in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were much less than the control.Thus, mitochondrial complex I function within astrocytes is essential for normal emergence from anesthesia. BACKGROUND In mice, restriction of loss of the mitochondrial complex I gene Ndufs4 to glutamatergic neurons confers a profound hypersensitivity to volatile anesthetics similar to that seen with global genetic knockout of Ndufs4. Astrocytes are crucial to glutamatergic synapse functioning during excitatory transmission. Therefore, the authors examined the role of astrocytes in the anesthetic hypersensitivity of Ndufs4(KO). METHODS A tamoxifen-activated astrocyte-specific Ndufs4(KO) mouse was constructed. The specificity of the astrocyte-specific inducible model was confirmed by using the green fluorescent protein reporter line Ai6. Approximately 120 astrocyte-specific knockout and control mice were used for the experiments. Mice were anesthetized with varying concentrations of isoflurane or halothane; loss of righting reflex and response to a tail clamp were determined and quantified as the induction and emergence EC50s. Because norepinephrine has been implicated in emergence from anesthesia and astrocytes respond to norepinephrine to release gliotransmitters, the authors measured norepinephrine levels in the brains of control and knockout Ndufs4 animals. RESULTS The induction EC50s for tail clamp in both isoflurane and halothane were similar between the control and astrocyte-specific Ndufs4(KO) mice at 3 weeks after 4-hydroxy tamoxifen injection (induction concentration, EC50(ind)-isoflurane: control = 1.27 ± 0.12, astrocyte-specific knockout = 1.21 ± 0.18, P = 0.495; halothane: control = 1.28 ± 0.05, astrocyte-specific knockout = 1.20 ± 0.05, P = 0.017). However, the emergent concentrations in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were less than the controls for tail clamp; (emergence concentration, EC50(em)-isoflurane: control = 1.18 ± 0.10, astrocyte-specific knockout = 0.67 ± 0.11, P < 0.0001; halothane: control = 1.08 ± 0.09, astrocyte-specific knockout = 0.59 ± 0.12, P < 0.0001). The induction EC50s for loss of righting reflex were also similar between the control and astrocyte-specific Ndufs4(KO) mice (EC50(ind)-isoflurane: control = 1.02 ± 0.10, astrocyte-specific knockout = 0.97 ± 0.06, P = 0.264; halothane: control = 1.03 ± 0.05, astrocyte-specific knockout = 0.99 ± 0.08, P = 0.207). The emergent concentrations for loss of righting reflex in both anesthetics for the astrocyte-specific Ndufs4(KO) mice were less than the control (EC50(em)-isoflurane: control = 1.0 ± 0.07, astrocyte-specific knockout = 0.62 ± 0.12, P < 0.0001; halothane: control = 1.0 ± 0.04, astrocyte-specific KO = 0.64 ± 0.09, P < 0.0001); N ≥ 6 for control and astrocyte-specific Ndufs4(KO) mice. For all tests, similar results were seen at 7 weeks after 4-hydroxy tamoxifen injection. The total norepinephrine content of the brain in global or astrocyte-specific Ndufs4(KO) mice was unchanged compared to control mice. CONCLUSIONS The only phenotype of the astrocyte-specific Ndufs4(KO) mouse was a specific impairment in emergence from volatile anesthetic-induced general anesthesia. The authors conclude that normal mitochondrial function within astrocytes is essential for emergence from anesthesia.
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Affiliation(s)
- Renjini Ramadasan-Nair
- From the Center for Integrative Brain Research, Seattle Children's Research Institute, Washington (R.R.-N., J.H., L.S.I., P.G.M., M.M.S.) the Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, Washington (P.G.M., M.M.S.)
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Perouansky M, Hemmings HC. Bioblasts, anaesthesia, and power failure: rein in the excitement. Br J Anaesth 2018; 120:891-895. [PMID: 29661404 DOI: 10.1016/j.bja.2018.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 02/19/2018] [Indexed: 11/30/2022] Open
Affiliation(s)
- M Perouansky
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA.
| | - H C Hemmings
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
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Zimin PI, Woods CB, Kayser EB, Ramirez JM, Morgan PG, Sedensky MM. Isoflurane disrupts excitatory neurotransmitter dynamics via inhibition of mitochondrial complex I. Br J Anaesth 2018; 120:1019-1032. [PMID: 29661379 DOI: 10.1016/j.bja.2018.01.036] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 01/08/2018] [Accepted: 02/09/2018] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The mechanisms of action of volatile anaesthetics are unclear. Volatile anaesthetics selectively inhibit complex I in the mitochondrial respiratory chain. Mice in which the mitochondrial complex I subunit NDUFS4 is knocked out [Ndufs4(KO)] either globally or in glutamatergic neurons are hypersensitive to volatile anaesthetics. The volatile anaesthetic isoflurane selectively decreases the frequency of spontaneous excitatory events in hippocampal slices from Ndufs4(KO) mice. METHODS Complex I inhibition by isoflurane was assessed with a Clark electrode. Synaptic function was measured by stimulating Schaffer collateral fibres and recording field potentials in the hippocampus CA1 region. RESULTS Isoflurane specifically inhibits complex I dependent respiration at lower concentrations in mitochondria from Ndufs4(KO) than from wild-type mice. In hippocampal slices, after high frequency stimulation to increase energetic demand, short-term synaptic potentiation is less in KO compared with wild-type mice. After high frequency stimulation, both Ndufs4(KO) and wild-type hippocampal slices exhibit striking synaptic depression in isoflurane at twice the 50% effective concentrations (EC50). The pattern of synaptic depression by isoflurane indicates a failure in synaptic vesicle recycling. Application of a selective A1 adenosine receptor antagonist partially eliminates isoflurane-induced short-term depression in both wild-type and Ndufs4(KO) slices, implicating an additional mitochondria-dependent effect on exocytosis. When mitochondria are the sole energy source, isoflurane completely eliminates synaptic output in both mutant and wild-type mice at twice the (EC50) for anaesthesia. CONCLUSIONS Volatile anaesthetics directly inhibit mitochondrial complex I as a primary target, limiting synaptic ATP production, and excitatory vesicle endocytosis and exocytosis.
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Affiliation(s)
- P I Zimin
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA.
| | - C B Woods
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - E B Kayser
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - J M Ramirez
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Neurological Surgery, University of Washington, Seattle, WA, USA
| | - P G Morgan
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
| | - M M Sedensky
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
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Abstract
It is difficult to study the genetics and molecular mechanisms of anesthesia in humans. Fortunately, the genetic approaches in model organisms can, and have, led to profound insights as to the targets of anesthetics. In turn, the organization of these putative targets into meaningful pathways has begun to elucidate the mechanisms of action of these agents. However, it is important to first appreciate the strengths, and limitations, of genetic approaches to understand the anesthetic action. Here we compare the commonly used genetic model organisms, various anesthetic endpoints, and different modes of genetic screens. Coupled with the more specific data presented in subsequent chapters, this chapter places those results in a framework with which to analyze the discoveries across organisms and eventually extend the resulting models to humans.
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Olufs ZPG, Loewen CA, Ganetzky B, Wassarman DA, Perouansky M. Genetic variability affects absolute and relative potencies and kinetics of the anesthetics isoflurane and sevoflurane in Drosophila melanogaster. Sci Rep 2018; 8:2348. [PMID: 29402974 PMCID: PMC5799260 DOI: 10.1038/s41598-018-20720-7] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 01/24/2018] [Indexed: 01/12/2023] Open
Abstract
Genetic variability affects the response to numerous xenobiotics but its role in the clinically-observed irregular responses to general anesthetics remains uncertain. To investigate the pharmacogenetics of volatile general anesthetics (VGAs), we developed a Serial Anesthesia Array apparatus to expose multiple Drosophila melanogaster samples to VGAs and behavioral assays to determine pharmacokinetic and pharmacodynamic properties of VGAs. We studied the VGAs isoflurane and sevoflurane in four wild type strains from the Drosophila Genetic Reference Panel, two commonly used laboratory strains (Canton S and w 1118 ), and a mutant in Complex I of the mitochondrial electron transport chain (ND23 60114 ). In all seven strains, isoflurane was more potent than sevoflurane, as predicted by their relative lipid solubilities, and emergence from isoflurane was slower than from sevoflurane, reproducing cardinal pharmacokinetic and pharmacodynamic properties in mammals. In addition, ND23 60114 flies were more sensitive to both agents, as observed in worms, mice, and humans carrying Complex I mutations. Moreover, we found substantial variability among the fly strains both in absolute and in relative pharmacokinetic and pharmacodynamic profiles of isoflurane and sevoflurane. These data indicate that naturally occurring genetic variations measurably influence cardinal pharmacologic properties of VGAs and that flies can be used to identify relevant genetic variations.
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Affiliation(s)
- Zachariah P G Olufs
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Carin A Loewen
- Department of Genetics, College of Agriculture and Life Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Barry Ganetzky
- Department of Genetics, College of Agriculture and Life Sciences, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - David A Wassarman
- Department of Medical Genetics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Misha Perouansky
- Department of Anesthesiology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, 53706, USA.
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Regional knockdown of NDUFS4 implicates a thalamocortical circuit mediating anesthetic sensitivity. PLoS One 2017; 12:e0188087. [PMID: 29136012 PMCID: PMC5685608 DOI: 10.1371/journal.pone.0188087] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 10/31/2017] [Indexed: 12/28/2022] Open
Abstract
Knockout of the mitochondrial complex I protein, NDUFS4, profoundly increases sensitivity of mice to volatile anesthetics. In mice carrying an Ndufs4lox/lox gene, adeno-associated virus expressing Cre recombinase was injected into regions of the brain postulated to affect sensitivity to volatile anesthetics. These injections generated otherwise phenotypically wild type mice with region-specific, postnatal inactivation of Ndufs4, minimizing developmental effects of gene loss. Sensitivities to the volatile anesthetics isoflurane and halothane were measured using loss of righting reflex (LORR) and movement in response to tail clamp (TC) as endpoints. Knockdown (KD) of Ndufs4 in the vestibular nucleus produced resistance to both anesthetics for movement in response to TC. Ndufs4 loss in the central and dorsal medial thalami and in the parietal association cortex increased anesthetic sensitivity to both TC and LORR. Knockdown of Ndufs4 only in the parietal association cortex produced striking hypersensitivity for both endpoints, and accounted for half the total change seen in the global KO (Ndufs4(KO)). Excitatory synaptic transmission in the parietal association cortex in slices from Ndufs4(KO) animals was hypersensitive to isoflurane compared to control slices. We identified a direct neural circuit between the parietal association cortex and the central thalamus, consistent with a model in which isoflurane sensitivity is mediated by a thalamic signal relayed through excitatory synapses to the parietal association cortex. We postulate that the thalamocortical circuit is crucial for maintenance of consciousness and is disrupted by the inhibitory effects of isoflurane/halothane on mitochondria.
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van der Bliek AM, Sedensky MM, Morgan PG. Cell Biology of the Mitochondrion. Genetics 2017; 207:843-871. [PMID: 29097398 PMCID: PMC5676242 DOI: 10.1534/genetics.117.300262] [Citation(s) in RCA: 244] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 09/05/2017] [Indexed: 01/19/2023] Open
Abstract
Mitochondria are best known for harboring pathways involved in ATP synthesis through the tricarboxylic acid cycle and oxidative phosphorylation. Major advances in understanding these roles were made with Caenorhabditiselegans mutants affecting key components of the metabolic pathways. These mutants have not only helped elucidate some of the intricacies of metabolism pathways, but they have also served as jumping off points for pharmacology, toxicology, and aging studies. The field of mitochondria research has also undergone a renaissance, with the increased appreciation of the role of mitochondria in cell processes other than energy production. Here, we focus on discoveries that were made using C. elegans, with a few excursions into areas that were studied more thoroughly in other organisms, like mitochondrial protein import in yeast. Advances in mitochondrial biogenesis and membrane dynamics were made through the discoveries of novel functions in mitochondrial fission and fusion proteins. Some of these functions were only apparent through the use of diverse model systems, such as C. elegans Studies of stress responses, exemplified by mitophagy and the mitochondrial unfolded protein response, have also benefitted greatly from the use of model organisms. Recent developments include the discoveries in C. elegans of cell autonomous and nonautonomous pathways controlling the mitochondrial unfolded protein response, as well as mechanisms for degradation of paternal mitochondria after fertilization. The evolutionary conservation of many, if not all, of these pathways ensures that results obtained with C. elegans are equally applicable to studies of human mitochondria in health and disease.
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Affiliation(s)
- Alexander M van der Bliek
- Department of Biological Chemistry, Jonsson Comprehensive Cancer Center and Molecular Biology Institute, David Geffen School of Medicine at UCLA, Los Angeles, California 90024
| | - Margaret M Sedensky
- Department of Anesthesiology and Pain Medicine, University of Washington and Center for Developmental Therapeutics, Seattle Children's Research Institute, Washington 98101
| | - Phil G Morgan
- Department of Anesthesiology and Pain Medicine, University of Washington and Center for Developmental Therapeutics, Seattle Children's Research Institute, Washington 98101
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Abstract
Abstract
Background
Previous studies showed that synaptic transmission is affected by general anesthetics, but an anesthetic dose response in freely moving animals has not been done. The hippocampus provides a neural network for the evaluation of isoflurane and pentobarbital on multisynaptic transmission that is relevant to memory function.
Methods
Male Long-Evans rats were implanted with multichannel and single electrodes in the hippocampus. Spontaneous local field potentials and evoked field potentials were recorded in freely behaving rats before (baseline) and after various doses of isoflurane (0.25 to 1.5%) and sodium pentobarbital (10 mg/kg intraperitoneal).
Results
Monosynaptic population excitatory postsynaptic potentials at the basal and apical dendrites of CA1 were significantly decreased at greater than or equal to 0.25% (n = 4) and greater than or equal to 1.0% (n = 6) isoflurane, respectively. The perforant path evoked multisynaptic response at CA1 was decreased by ~50% at greater than or equal to 0.25% isoflurane (n = 5). A decreased population excitatory postsynaptic potential was accompanied by increased paired-pulse facilitation. Population spike amplitude in relation to apical dendritic population excitatory postsynaptic potential was not significantly altered by isoflurane. Spontaneous hippocampal local field potential at 0.8 to 300 Hz was dose-dependently suppressed by isoflurane (n = 6), with local field potential power in the 50- to 150-Hz band showing the highest decrease with isoflurane dose, commensurate with the decrease in trisynaptic CA1 response. Low-dose pentobarbital (n = 7) administration decreased the perforant path evoked trisynaptic CA1 response and hippocampal local field potentials at 78 to 125 Hz.
Conclusions
Hippocampal networks are sensitive to low doses of isoflurane and pentobarbital, possibly through both glutamatergic and γ-aminobutyric acid–mediated transmission. Network disruption could help explain the impairment of hippocampal-dependent cognitive functions with low-dose anesthetic.
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