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Ahlström S, Reiterä P, Jokela R, Olkkola KT, Kaunisto MA, Kalso E. Influence of Clinical and Genetic Factors on Propofol Dose Requirements: A Genome-wide Association Study. Anesthesiology 2024; 141:300-312. [PMID: 38700459 DOI: 10.1097/aln.0000000000005036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
BACKGROUND Propofol is a widely used intravenous hypnotic. Dosing is based mostly on weight, with great interindividual variation in consumption. Suggested factors affecting propofol requirements include age, sex, ethnicity, anxiety, alcohol consumption, smoking, and concomitant valproate use. Genetic factors have not been widely explored. METHODS This study considered 1,000 women undergoing breast cancer surgery under propofol and remifentanil anesthesia. Depth of anesthesia was monitored with State Entropy (GE Healthcare, Finland). Propofol requirements during surgery were recorded. DNA from blood was genotyped with a genome-wide array. A multivariable linear regression model was used to assess the relevance of clinical variables and select those to be used as covariates in a genome-wide association study. Imputed genotype data were used to explore selected loci further. In silico functional annotation was used to explore possible consequences of the discovered genetic variants. Additionally, previously reported genetic associations from candidate gene studies were tested. RESULTS Body mass index, smoking status, alcohol use, remifentanil dose (ln[mg · kg-1 · min-1]), and average State Entropy during surgery remained statistically significant in the multivariable model. Two loci reached genome-wide significance (P < 5 × 10-8). The most significant associations were for single-nucleotide polymorphisms rs997989 (30 kb from ROBO3), likely affecting expression of another nearby gene, FEZ1, and rs9518419, close to NALCN (sodium leak channel); rs10512538 near KCNJ2 encoding the Kir2.1 potassium channel showed suggestive association (P = 4.7 × 10-7). None of these single-nucleotide polymorphisms are coding variants but possibly affect the regulation of nearby genes. None of the single-nucleotide polymorphisms previously reported as affecting propofol pharmacokinetics or pharmacodynamics showed association in the data. CONCLUSIONS In this first genome-wide association study exploring propofol requirements, This study discovered novel genetic associations suggesting new biologically relevant pathways for propofol and general anesthesia. The roles of the gene products of ROBO3/FEZ1, NALCN, and KCNJ2 in propofol anesthesia warrant further studies. EDITOR’S PERSPECTIVE
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Affiliation(s)
- Sirkku Ahlström
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland
| | - Paula Reiterä
- Department of Public Health, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland
| | - Ritva Jokela
- HUS Shared Group Services, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland
| | - Klaus T Olkkola
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland; INDIVIDRUG Research Program, Faculty of Medicine, University of Helsinki, Finland
| | - Mari A Kaunisto
- Institute for Molecular Medicine Finland, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Eija Kalso
- Department of Anesthesiology, Intensive Care and Pain Medicine, University of Helsinki and HUS Helsinki University Hospital, Helsinki, Finland; Department of Pharmacology, Faculty of Medicine, University of Helsinki, Finland; SleepWell Research Program, Faculty of Medicine, University of Helsinki, Finland
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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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Cylinder DM, van Zundert AA, Solt K, van Swinderen B. Time to Wake Up! The Ongoing Search for General Anesthetic Reversal Agents. Anesthesiology 2024; 140:610-627. [PMID: 38349760 PMCID: PMC10868874 DOI: 10.1097/aln.0000000000004846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
How general anesthetics work remains a topic of ongoing study. A parallel field of research has sought to identify methods to reverse general anesthesia. Reversal agents could shorten patients' recovery time and potentially reduce the risk of postoperative complications. An incomplete understanding of the mechanisms of general anesthesia has hampered the pursuit for reversal agents. Nevertheless, the search for reversal agents has furthered understanding of the mechanisms underlying general anesthesia. The study of potential reversal agents has highlighted the importance of rigorous criteria to assess recovery from general anesthesia in animal models, and has helped identify key arousal systems (e.g., cholinergic, dopaminergic, and orexinergic systems) relevant to emergence from general anesthesia. Furthermore, the effects of reversal agents have been found to be inconsistent across different general anesthetics, revealing differences in mechanisms among these drugs. The presynapse and glia probably also contribute to general anesthesia recovery alongside postsynaptic receptors. The next stage in the search for reversal agents will have to consider alternate mechanisms encompassing the tripartite synapse.
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Affiliation(s)
- Drew M. Cylinder
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - André A.J. van Zundert
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Department of Anaesthesia and Perioperative Medicine, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
| | - Ken Solt
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston, MA, U.S.A
- Department of Anaesthesia, Harvard Medical School, Boston, MA, U.S.A
| | - Bruno van Swinderen
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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Božić M, Pirnat S, Fink K, Potokar M, Kreft M, Zorec R, Stenovec M. Ketamine Reduces the Surface Density of the Astroglial Kir4.1 Channel and Inhibits Voltage-Activated Currents in a Manner Similar to the Action of Ba 2+ on K + Currents. Cells 2023; 12:1360. [PMID: 37408194 DOI: 10.3390/cells12101360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 07/07/2023] Open
Abstract
A single sub-anesthetic dose of ketamine evokes rapid and long-lasting beneficial effects in patients with a major depressive disorder. However, the mechanisms underlying this effect are unknown. It has been proposed that astrocyte dysregulation of extracellular K+ concentration ([K+]o) alters neuronal excitability, thus contributing to depression. We examined how ketamine affects inwardly rectifying K+ channel Kir4.1, the principal regulator of K+ buffering and neuronal excitability in the brain. Cultured rat cortical astrocytes were transfected with plasmid-encoding fluorescently tagged Kir4.1 (Kir4.1-EGFP) to monitor the mobility of Kir4.1-EGFP vesicles at rest and after ketamine treatment (2.5 or 25 µM). Short-term (30 min) ketamine treatment reduced the mobility of Kir4.1-EGFP vesicles compared with the vehicle-treated controls (p < 0.05). Astrocyte treatment (24 h) with dbcAMP (dibutyryl cyclic adenosine 5'-monophosphate, 1 mM) or [K+]o (15 mM), which increases intracellular cAMP, mimicked the ketamine-evoked reduction of mobility. Live cell immunolabelling and patch-clamp measurements in cultured mouse astrocytes revealed that short-term ketamine treatment reduced the surface density of Kir4.1 and inhibited voltage-activated currents similar to Ba2+ (300 µM), a Kir4.1 blocker. Thus, ketamine attenuates Kir4.1 vesicle mobility, likely via a cAMP-dependent mechanism, reduces Kir4.1 surface density, and inhibits voltage-activated currents similar to Ba2+, known to block Kir4.1 channels.
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Affiliation(s)
- Mićo Božić
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Department of Medical Oncology, Institute of Oncology Ljubljana, Zaloška 2, 1000 Ljubljana, Slovenia
| | - Samo Pirnat
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Katja Fink
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
| | - Maja Potokar
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Marko Kreft
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
- Department of Biology, Biotechnical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
| | - Matjaž Stenovec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
- Celica Biomedical, Tehnološki Park 24, 1000 Ljubljana, Slovenia
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Li S, Wang DX, Zhao P, Luo A. Editorial: The mechanism and interventions of aging-related cognitive impairment in perioperative context. Front Aging Neurosci 2023; 15:1174890. [PMID: 37032831 PMCID: PMC10080121 DOI: 10.3389/fnagi.2023.1174890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 03/07/2023] [Indexed: 04/11/2023] Open
Affiliation(s)
- Shiyong Li
- Department of Anesthesiology, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, and Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dong-Xin Wang
- Department of Anesthesiology, Peking University First Hospital, Beijing, China
| | - Ping Zhao
- Department of Anesthesiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Ailin Luo
- Department of Anesthesiology, Hubei Key Laboratory of Geriatric Anesthesia and Perioperative Brain Health, and Wuhan Clinical Research Center for Geriatric Anesthesia, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Ailin Luo
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Garbouchian A, Montgomery AC, Gilbert SP, Bentley M. KAP is the neuronal organelle adaptor for Kinesin-2 KIF3AB and KIF3AC. Mol Biol Cell 2022; 33:ar133. [PMID: 36200888 PMCID: PMC9727798 DOI: 10.1091/mbc.e22-08-0336] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Kinesin-driven organelle transport is crucial for neuron development and maintenance, yet the mechanisms by which kinesins specifically bind their organelle cargoes remain undefined. In contrast to other transport kinesins, the neuronal function and specific organelle adaptors of heterodimeric Kinesin-2 family members KIF3AB and KIF3AC remain unknown. We developed a novel microscopy-based assay to define protein-protein interactions in intact neurons. The experiments found that both KIF3AB and KIF3AC bind kinesin-associated protein (KAP). These interactions are mediated by the distal C-terminal tail regions and not the coiled-coil domain. We used live-cell imaging in cultured hippocampal neurons to define the localization and trafficking parameters of KIF3AB and KIF3AC organelle populations. We discovered that KIF3AB/KAP and KIF3AC/KAP bind the same organelle populations and defined their transport parameters in axons and dendrites. The results also show that ∼12% of KIF3 organelles contain the RNA-binding protein adenomatous polyposis coli. These data point toward a model in which KIF3AB and KIF3AC use KAP as their neuronal organelle adaptor and that these kinesins mediate transport of a range of organelles.
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Affiliation(s)
- Alex Garbouchian
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Andrew C. Montgomery
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Susan P. Gilbert
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Marvin Bentley
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180,*Address correspondence to: Marvin Bentley ()
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7
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Frank M, Nabb AT, Gilbert SP, Bentley M. Propofol attenuates kinesin-mediated axonal vesicle transport and fusion. Mol Biol Cell 2022; 33:ar119. [PMID: 36103253 PMCID: PMC9634964 DOI: 10.1091/mbc.e22-07-0276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Propofol is a widely used general anesthetic, yet the understanding of its cellular effects is fragmentary. General anesthetics are not as innocuous as once believed and have a wide range of molecular targets that include kinesin motors. Propofol, ketamine, and etomidate reduce the distances that Kinesin-1 KIF5 and Kinesin-2 KIF3 travel along microtubules in vitro. These transport kinesins are highly expressed in the CNS, and their dysfunction leads to a range of human pathologies including neurodevelopmental and neurodegenerative diseases. While in vitro data suggest that general anesthetics may disrupt kinesin transport in neurons, this hypothesis remains untested. Here we find that propofol treatment of hippocampal neurons decreased vesicle transport mediated by Kinesin-1 KIF5 and Kinesin-3 KIF1A ∼25-60%. Propofol treatment delayed delivery of the KIF5 cargo NgCAM to the distal axon. Because KIF1A participates in axonal transport of presynaptic vesicles, we tested whether prolonged propofol treatment affects synaptic vesicle fusion mediated by VAMP2. The data show that propofol-induced transport delay causes a significant decrease in vesicle fusion in distal axons. These results are the first to link a propofol-induced delay in neuronal trafficking to a decrease in axonal vesicle fusion, which may alter physiological function during and after anesthesia.
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Affiliation(s)
- Madeline Frank
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Alec T. Nabb
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Susan P. Gilbert
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Marvin Bentley
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180,*Address correspondence to: Marvin Bentley ()
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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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Yang E, Bu W, Suma A, Carnevale V, Grasty KC, Loll PJ, Woll K, Bhanu N, Garcia BA, Eckenhoff RG, Covarrubias M. Binding Sites and the Mechanism of Action of Propofol and a Photoreactive Analogue in Prokaryotic Voltage-Gated Sodium Channels. ACS Chem Neurosci 2021; 12:3898-3914. [PMID: 34607428 DOI: 10.1021/acschemneuro.1c00495] [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: 01/16/2023] Open
Abstract
Propofol, one of the most commonly used intravenous general anesthetics, modulates neuronal function by interacting with ion channels. The mechanisms that link propofol binding to the modulation of distinct ion channel states, however, are not understood. To tackle this problem, we investigated the prokaryotic ancestors of eukaryotic voltage-gated Na+ channels (Navs) using unbiased photoaffinity labeling (PAL) with a diazirine derivative of propofol (AziPm), electrophysiological methods, and mutagenesis. AziPm inhibits Nav function in a manner that is indistinguishable from that of the parent compound by promoting activation-coupled inactivation. In several replicates (8/9) involving NaChBac and NavMs, we found adducts at residues located at the C-terminal end of the S4 voltage sensor, the S4-S5 linker, and the N-terminal end of the S5 segment. However, the non-inactivating mutant NaChBac-T220A yielded adducts that were different from those found in the wild-type counterpart, which suggested state-dependent changes at the binding site. Then, using molecular dynamics simulations to further elucidate the structural basis of Nav modulation by propofol, we show that the S4 voltage sensors and the S4-S5 linkers shape two distinct propofol binding sites in a conformation-dependent manner. Supporting the PAL and MD simulation results, we also found that Ala mutations of a subset of adducted residues have distinct effects on gating modulation of NaChBac and NavMs by propofol. The results of this study provide direct insights into the structural basis of the mechanism through which propofol binding promotes activation-coupled inactivation to inhibit Nav channel function.
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Affiliation(s)
- Elaine Yang
- Department of Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
| | - Weiming Bu
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Antonio Suma
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, United States
- Dipartimento di Fisica, Universit̀a di Bari, and Sezione INFN di Bari, via Amendola 173, Bari 70126, Italy
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, United States
| | - Kimberly C. Grasty
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, Pennsylvania 19102, United States
| | - Patrick J. Loll
- Department of Biochemistry and Molecular Biology, College of Medicine, Drexel University, Philadelphia, Pennsylvania 19102, United States
| | - Kellie Woll
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Natarajan Bhanu
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Benjamin A. Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Roderic G. Eckenhoff
- Department of Anesthesiology and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Manuel Covarrubias
- Department of Neuroscience, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
- Bluemle Life Sciences Building, 233 S 10th Street, Room 231, Philadelphia, Pennsylvania 19107, United States
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Ketamine Alters Functional Plasticity of Astroglia: An Implication for Antidepressant Effect. Life (Basel) 2021; 11:life11060573. [PMID: 34204579 PMCID: PMC8234122 DOI: 10.3390/life11060573] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 12/28/2022] Open
Abstract
Ketamine, a non-competitive N–methyl–d–aspartate receptor (NMDAR) antagonist, exerts a rapid, potent and long-lasting antidepressant effect, although the cellular and molecular mechanisms of this action are yet to be clarified. In addition to targeting neuronal NMDARs fundamental for synaptic transmission, ketamine also affects the function of astrocytes, the key homeostatic cells of the central nervous system that contribute to pathophysiology of major depressive disorder. Here, I review studies revealing that (sub)anesthetic doses of ketamine elevate intracellular cAMP concentration ([cAMP]i) in astrocytes, attenuate stimulus-evoked astrocyte calcium signaling, which regulates exocytotic secretion of gliosignaling molecules, and stabilize the vesicle fusion pore in a narrow configuration, possibly hindering cargo discharge or vesicle recycling. Next, I discuss how ketamine affects astrocyte capacity to control extracellular K+ by reducing vesicular delivery of the inward rectifying potassium channel (Kir4.1) to the plasmalemma that reduces the surface density of Kir4.1. Modified astroglial K+ buffering impacts upon neuronal firing pattern as demonstrated in lateral habenula in a rat model of depression. Finally, I highlight the discovery that ketamine rapidly redistributes cholesterol in the astrocyte plasmalemma, which may alter the flux of cholesterol to neurons. This structural modification may further modulate a host of processes that synergistically contribute to ketamine’s rapid antidepressant action.
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Mechanistic basis of propofol-induced disruption of kinesin processivity. Proc Natl Acad Sci U S A 2021; 118:2023659118. [PMID: 33495322 DOI: 10.1073/pnas.2023659118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Propofol is a widely used general anesthetic to induce and maintain anesthesia, and its effects are thought to occur through impact on the ligand-gated channels including the GABAA receptor. Propofol also interacts with a large number of proteins including molecular motors and inhibits kinesin processivity, resulting in significant decrease in the run length for conventional kinesin-1 and kinesin-2. However, the molecular mechanism by which propofol achieves this outcome is not known. The structural transition in the kinesin neck-linker region is crucial for its processivity. In this study, we analyzed the effect of propofol and its fluorine derivative (fropofol) on the transition in the neck-linker region of kinesin. Propofol binds at two crucial surfaces in the leading head: one at the microtubule-binding interface and the other in the neck-linker region. We observed in both the cases the order-disorder transition of the neck-linker was disrupted and kinesin lost its signal for forward movement. In contrast, there was not an effect on the neck-linker transition with propofol binding at the trailing head. Free-energy calculations show that propofol at the microtubule-binding surface significantly reduces the microtubule-binding affinity of the kinesin head. While propofol makes pi-pi stacking and H-bond interactions with the propofol binding cavity, fropofol is unable to make a suitable interaction at this binding surface. Therefore, the binding affinity of fropofol is much lower compared to propofol. Hence, this study provides a mechanism by which propofol disrupts kinesin processivity and identifies transitions in the ATPase stepping cycle likely affected.
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Yang N, Li Z, Han D, Mi X, Tian M, Liu T, Li Y, He J, Kuang C, Cao Y, Li L, Ni C, Wang JQ, Guo X. Autophagy prevents hippocampal α-synuclein oligomerization and early cognitive dysfunction after anesthesia/surgery in aged rats. Aging (Albany NY) 2020; 12:7262-7281. [PMID: 32335546 PMCID: PMC7202547 DOI: 10.18632/aging.103074] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 03/29/2020] [Indexed: 12/13/2022]
Abstract
Stress-induced α-synuclein aggregation, especially the most toxic species (oligomers), may precede synaptic and cognitive dysfunction. Under pathological conditions, α-synuclein is degraded primarily through the autophagic/lysosomal pathway. We assessed the involvement of autophagy in α-synuclein aggregation and cognitive impairment following general anesthesia and surgical stress. Autophagy was found to be suppressed in the aged rat hippocampus after either 4-h propofol anesthesia alone or 2-h propofol anesthesia during a laparotomy surgery. This inhibition of autophagy was accompanied by profound α-synuclein oligomer aggregation and neurotransmitter imbalances in the hippocampus, along with hippocampus-dependent cognitive deficits. These events were not observed 18 weeks after propofol exposure with or without surgical stress. The pharmacological induction of autophagy using rapamycin markedly suppressed α-synuclein oligomerization, restored neurotransmitter equilibrium, and improved cognitive behavior after prolonged anesthesia or anesthesia combined with surgery. Thus, both prolonged propofol anesthesia alone and propofol anesthesia during surgery impaired autophagy, which may have induced abnormal hippocampal α-synuclein aggregation and neurobehavioral deficits in aged rats. These findings suggest that the activation of autophagy and the clearance of pathological α-synuclein oligomers may be novel strategies to ameliorate the common occurrence of postoperative cognitive dysfunction.
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Affiliation(s)
- Ning Yang
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Zhengqian Li
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Dengyang Han
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Xinning Mi
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Miao Tian
- Chinese Traditional and Herbal Drugs Editorial Office, Tianjin Institute of Pharmaceutical Research, Tianjin 300193, China
| | - Taotao Liu
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Yue Li
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Jindan He
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Chongshen Kuang
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Yiyun Cao
- Department of Anesthesiology, Shanghai Sixth People's Hospital East Affiliated with Shanghai University of Medicine and Health Sciences, Shanghai 200233, China
| | - Lunxu Li
- Department of Anesthesiology, Peking University International Hospital, Beijing 102200, China
| | - Cheng Ni
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - John Q Wang
- Department of Anesthesiology, University of Missouri Kansas City, School of Medicine, Kansas, MO 64110, USA
| | - Xiangyang Guo
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
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13
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Franchini DM, Lanvin O, Tosolini M, Patras de Campaigno E, Cammas A, Péricart S, Scarlata CM, Lebras M, Rossi C, Ligat L, Pont F, Arimondo PB, Laurent C, Ayyoub M, Despas F, Lapeyre-Mestre M, Millevoi S, Fournié JJ. Microtubule-Driven Stress Granule Dynamics Regulate Inhibitory Immune Checkpoint Expression in T Cells. Cell Rep 2020; 26:94-107.e7. [PMID: 30605689 DOI: 10.1016/j.celrep.2018.12.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/02/2018] [Accepted: 12/03/2018] [Indexed: 12/31/2022] Open
Abstract
Despite the clinical success of blocking inhibitory immune checkpoint receptors such as programmed cell death-1 (PD-1) in cancer, the mechanisms controlling the expression of these receptors have not been fully elucidated. Here, we identify a post-transcriptional mechanism regulating PD-1 expression in T cells. Upon activation, the PDCD1 mRNA and ribonucleoprotein complexes coalesce into stress granules that require microtubules and the kinesin 1 molecular motor to proceed to translation. Hence, PD-1 expression is highly sensitive to microtubule or stress granule inhibitors targeting this pathway. Evidence from healthy donors and cancer patients reveals a common regulation for the translation of CTLA4, LAG3, TIM3, TIGIT, and BTLA but not of the stimulatory co-receptors OX40, GITR, and 4-1BB mRNAs. In patients, disproportionality analysis of immune-related adverse events for currently used microtubule drugs unveils a significantly higher risk of autoimmunity. Our findings reveal a fundamental mechanism of immunoregulation with great importance in cancer immunotherapy.
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Affiliation(s)
- Don-Marc Franchini
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; ERL 5294, CNRS, 31037 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France; Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Institut Carnot Lymphome CALYM, 69495 Pierre-Benite, France.
| | - Olivia Lanvin
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; ERL 5294, CNRS, 31037 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France; Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Institut Carnot Lymphome CALYM, 69495 Pierre-Benite, France
| | - Marie Tosolini
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; ERL 5294, CNRS, 31037 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France; Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Institut Carnot Lymphome CALYM, 69495 Pierre-Benite, France
| | - Emilie Patras de Campaigno
- Medical and Clinical Pharmacology Unit, CHU Toulouse University Hospital, 31000 Toulouse, France; Medical and Pharmacoepidemiology Research Unit, INSERM 1027, 31000 Toulouse, France; Centre d'Investigations Cliniques, CIC 1436, Toulouse University Hospital, 31000 Toulouse, France
| | - Anne Cammas
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France
| | - Sarah Péricart
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; ERL 5294, CNRS, 31037 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France; Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Institut Carnot Lymphome CALYM, 69495 Pierre-Benite, France
| | - Clara-Maria Scarlata
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France
| | - Morgane Lebras
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France
| | - Cédric Rossi
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; ERL 5294, CNRS, 31037 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France; Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Institut Carnot Lymphome CALYM, 69495 Pierre-Benite, France
| | - Laetitia Ligat
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France
| | - Fréderic Pont
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France
| | - Paola B Arimondo
- Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Epigenetic Targeting of Cancer, FRE3600 CNRS, 31035 Toulouse, France
| | - Camille Laurent
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; ERL 5294, CNRS, 31037 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France; Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Institut Carnot Lymphome CALYM, 69495 Pierre-Benite, France
| | - Maha Ayyoub
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France
| | - Fabien Despas
- Medical and Clinical Pharmacology Unit, CHU Toulouse University Hospital, 31000 Toulouse, France; Medical and Pharmacoepidemiology Research Unit, INSERM 1027, 31000 Toulouse, France; Centre d'Investigations Cliniques, CIC 1436, Toulouse University Hospital, 31000 Toulouse, France
| | - Maryse Lapeyre-Mestre
- Medical and Clinical Pharmacology Unit, CHU Toulouse University Hospital, 31000 Toulouse, France; Medical and Pharmacoepidemiology Research Unit, INSERM 1027, 31000 Toulouse, France; Centre d'Investigations Cliniques, CIC 1436, Toulouse University Hospital, 31000 Toulouse, France
| | - Stefania Millevoi
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France.
| | - Jean-Jacques Fournié
- Cancer Research Centre of Toulouse, INSERM UMR 1037, 31037 Toulouse, France; Université Toulouse III Paul Sabatier, 31330 Toulouse, France; ERL 5294, CNRS, 31037 Toulouse, France; Institut Universitaire du Cancer de Toulouse-Oncopole, 31100 Toulouse, France; Laboratoire d'Excellence "TOUCAN," Toulouse, France; Programme Hospitalo-Universitaire en Cancérologie CAPTOR, 31059 Toulouse, France; Institut Carnot Lymphome CALYM, 69495 Pierre-Benite, France.
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14
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Deeb SK, Guzik-Lendrum S, Jeffrey JD, Gilbert SP. The ability of the kinesin-2 heterodimer KIF3AC to navigate microtubule networks is provided by the KIF3A motor domain. J Biol Chem 2019; 294:20070-20083. [PMID: 31748411 PMCID: PMC6937563 DOI: 10.1074/jbc.ra119.010725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 11/17/2019] [Indexed: 01/13/2023] Open
Abstract
Heterodimeric kinesin family member KIF3AC is a mammalian kinesin-2 that is highly expressed in the central nervous system and has been implicated in intracellular transport. KIF3AC is unusual in that the motility characteristics of KIF3C when expressed as a homodimer are exceeding slow, whereas homodimeric KIF3AA, as well as KIF3AC, have much faster ATPase kinetics and single molecule velocities. Heterodimeric KIF3AC and homodimeric KIF3AA and KIF3CC are processive, although the run length of KIF3AC exceeds that of KIF3AA and KIF3CC. KIF3C is of particular interest because it exhibits a signature 25-residue insert of glycine and serine residues in loop L11 of its motor domain, and this insert is not present in any other kinesin, suggesting that it confers specific properties to mammalian heterodimeric KIF3AC. To gain a better understanding of the mechanochemical potential of KIF3AC, we pursued a single molecule study to characterize the navigation ability of KIF3AC, KIF3AA, and KIF3CC when encountering microtubule intersections. The results show that all three motors exhibited a preference to remain on the same microtubule when approaching an intersection from the top microtubule, and the majority of track switches occurred from the bottom microtubule onto the top microtubule. Heterodimeric KIF3AC and homodimeric KIF3AA displayed a similar likelihood of switching tracks (36.1 and 32.3%, respectively). In contrast, KIF3CC detached at intersections (67.7%) rather than switch tracks. These results indicate that it is the properties of KIF3A that contribute largely to the ability of KIF3AC to switch microtubule tracks to navigate intersections.
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Affiliation(s)
- Stephanie K Deeb
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Stephanie Guzik-Lendrum
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Jasper D Jeffrey
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Susan P Gilbert
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
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15
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Ma J, Williams J, Eastwood D, Lin S, Qian X, Fang Q, Cope D, Yuan Z, Cao L, An J. High-dose Propofol Anesthesia Reduces the Occurrence of Postoperative Cognitive Dysfunction via Maintaining Cytoskeleton. Neuroscience 2019; 421:136-143. [PMID: 31682819 DOI: 10.1016/j.neuroscience.2019.09.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 09/13/2019] [Accepted: 09/16/2019] [Indexed: 12/15/2022]
Abstract
Postoperative cognitive dysfunction (POCD) is a common postoperative complication observed in patients following. Here we tested the molecular mechanisms of memory loss in hippocampus of rat POCD model. We found that high-dose propofol anesthesia significantly alleviated spatial memory loss. The proteomes and transcriptomes in hippocampus showed that hippocampal cytoskeleton related pathways were abnormal in low group while not in high group. The protein assays confirmed that hippocampal actin cytoskeleton was depolymerized in low group while maintained in high group. This study confirms that high-dose propofol anesthesia could mitigate the development of POCD and provides evidences for actin cytoskeleton associated with this syndrome.
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Affiliation(s)
- Jun Ma
- Department of Anesthesiology, Pain Medicine & CCM, Aviation General Hospital of China Medical University & Beijing Institute of Translational Medicine, Chinese Academy of Sciences, Beijing, China; Laboratory of Medical Cell Biology, College of Translational Medicine, China Medical University, Shenyang, China
| | - John Williams
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Derek Eastwood
- Murrayfield Hospital Wirral, Royal College of Anaesthetists, London, UK
| | - Siyu Lin
- Department of Anesthesiology, Pain Medicine & CCM, Aviation General Hospital of China Medical University & Beijing Institute of Translational Medicine, Chinese Academy of Sciences, Beijing, China
| | - Xiaoyan Qian
- Department of Anesthesiology, Pain Medicine & CCM, Aviation General Hospital of China Medical University & Beijing Institute of Translational Medicine, Chinese Academy of Sciences, Beijing, China
| | - Qiwu Fang
- Department of Anesthesiology, Pain Medicine & CCM, Aviation General Hospital of China Medical University & Beijing Institute of Translational Medicine, Chinese Academy of Sciences, Beijing, China
| | - Doris Cope
- Department of Anesthesiology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Zengqiang Yuan
- Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China
| | - Liu Cao
- Laboratory of Medical Cell Biology, College of Translational Medicine, China Medical University, Shenyang, China
| | - Jianxiong An
- Department of Anesthesiology, Pain Medicine & CCM, Aviation General Hospital of China Medical University & Beijing Institute of Translational Medicine, Chinese Academy of Sciences, Beijing, China.
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16
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Woll KA, Guzik-Lendrum S, Bensel BM, Bhanu NV, Dailey WP, Garcia BA, Gilbert SP, Eckenhoff RG. An allosteric propofol-binding site in kinesin disrupts kinesin-mediated processive movement on microtubules. J Biol Chem 2018; 293:11283-11295. [PMID: 29844014 PMCID: PMC6065180 DOI: 10.1074/jbc.ra118.002182] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 05/24/2018] [Indexed: 12/20/2022] Open
Abstract
Microtubule-based molecular motors mediate transport of intracellular cargo to subdomains in neurons. Previous evidence has suggested that the anesthetic propofol decreases the average run-length potential of the major anterograde transporters kinesin-1 and kinesin-2 without altering their velocity. This effect on kinesin has not been observed with other inhibitors, stimulating considerable interest in the underlying mechanism. Here, we used a photoactive derivative of propofol, meta-azipropofol (AziPm), to search for potential propofol-binding sites in kinesin. Single-molecule motility assays confirmed that AziPm and propofol similarly inhibit kinesin-1 and kinesin-2. We then applied AziPm in semiquantitative radiolabeling and MS microsequencing assays to identify propofol-binding sites within microtubule-kinesin complexes. The radiolabeling experiments suggested preferential AziPm binding to the ATP-bound microtubule-kinesin complex. The photolabeled residues were contained within the kinesin motor domain rather than at the motor domain-β-tubulin interface. No residues within the P-loop of kinesin were photolabeled, indicating an inhibitory mechanism that does not directly affect ATPase activity and has an effect on run length without changing velocity. Our results also indicated that when the kinesin motor interacts with the microtubule during its processive run, a site forms in kinesin to which propofol can then bind and allosterically disrupt the kinesin-microtubule interaction, resulting in kinesin detachment and run termination. The discovery of the propofol-binding allosteric site in kinesin may improve our understanding of the strict coordination of the motor heads during the processive run. We hypothesize that propofol's potent effect on intracellular transport contributes to various components of its anesthetic action.
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Affiliation(s)
- Kellie A Woll
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Stephanie Guzik-Lendrum
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Brandon M Bensel
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Natarajan V Bhanu
- Department of Biochemistry and Biophysics, Epigenetics Program, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - William P Dailey
- Department of Chemistry, University of Pennsylvania School of Arts and Sciences, Philadelphia, Pennsylvania 19104
| | - Benjamin A Garcia
- Department of Biochemistry and Biophysics, Epigenetics Program, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Susan P Gilbert
- Department of Biological Sciences and the Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180
| | - Roderic G Eckenhoff
- Department of Anesthesiology and Critical Care, University of Pennsylvania, Perelman School of Medicine, Philadelphia, Pennsylvania 19104.
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17
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Abstract
The precise mechanism by which propofol enhances GABAergic transmission remains unclear, but much progress has been made regarding the underlying structural and dynamic mechanisms. Furthermore, it is now clear that propofol has additional molecular targets, many of which are functionally influenced at concentrations achieved clinically. Focusing primarily on molecular targets, this brief review attempts to summarize some of this recent progress while pointing out knowledge gaps and controversies. It is not intended to be comprehensive but rather to stimulate further thought, discussion, and study on the mechanisms by which propofol produces its pleiotropic effects.
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Affiliation(s)
- Pei Tang
- Department of Anesthesiology, University of Pittsburgh, 3550 Terrace Street, Pittsburgh, PA, 15261, USA
| | - Roderic Eckenhoff
- Department of Anesthesiology & Critical Care, University of Pennsylvania, 3400 Spruce St, Philadelphia, PA, 19104, USA
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18
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Abstract
Kinesins are a superfamily of ATP-dependent motors important for many microtubule-based functions, including multiple roles in mitosis. Small-molecule inhibitors of mitotic kinesins disrupt cell division and are being developed as antimitotic therapies. We investigated the molecular mechanism of the multitasking human mitotic kinesin Kif18A and its inhibition by the small molecule BTB-1. We used cryo-electron microscopy to visualize nucleotide-dependent conformational changes in microtubule-bound Kif18A, and the conformation of microtubule-bound, BTB-1-bound Kif18A. We calculated a putative BTB-1–binding site and validated this site experimentally to reveal the BTB-1 inhibition mechanism. Our work points to a general mechanism of kinesin inhibition, with wide implications for a targeted blockade of these motors in both dividing and interphase cells. Kinesin motors play diverse roles in mitosis and are targets for antimitotic drugs. The clinical significance of these motors emphasizes the importance of understanding the molecular basis of their function. Equally important, investigations into the modes of inhibition of these motors provide crucial information about their molecular mechanisms. Kif18A regulates spindle microtubules through its dual functionality, with microtubule-based stepping and regulation of microtubule dynamics. We investigated the mechanism of Kif18A and its inhibition by the small molecule BTB-1. The Kif18A motor domain drives ATP-dependent plus-end microtubule gliding, and undergoes conformational changes consistent with canonical mechanisms of plus-end–directed motility. The Kif18A motor domain also depolymerizes microtubule plus and minus ends. BTB-1 inhibits both of these microtubule-based Kif18A activities. A reconstruction of BTB-1–bound, microtubule-bound Kif18A, in combination with computational modeling, identified an allosteric BTB-1–binding site near loop5, where it blocks the ATP-dependent conformational changes that we characterized. Strikingly, BTB-1 binding is close to that of well-characterized Kif11 inhibitors that block tight microtubule binding, whereas BTB-1 traps Kif18A on the microtubule. Our work highlights a general mechanism of kinesin inhibition in which small-molecule binding near loop5 prevents a range of conformational changes, blocking motor function.
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