1
|
Romer SH, Miller KM, Sonner MJ, Ethridge VT, Gargas NM, Rohan JG. Changes in motor behavior and lumbar motoneuron morphology following repeated chlorpyrifos exposure in rats. PLoS One 2024; 19:e0305173. [PMID: 38875300 PMCID: PMC11178230 DOI: 10.1371/journal.pone.0305173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/26/2024] [Indexed: 06/16/2024] Open
Abstract
Chlorpyrifos is an organophosphate pesticide associated with numerous health effects including motor performance decrements. While many studies have focused on the health effects following acute chlorpyrifos poisonings, almost no studies have examined the effects on motoneurons following occupational-like exposures. The main objective of this study was to examine the broad effects of repeated occupational-like chlorpyrifos exposures on spinal motoneuron soma size relative to motor activity. To execute our objective, adult rats were exposed to chlorpyrifos via oral gavage once a day, five days a week for two weeks. Chlorpyrifos exposure effects were assessed either three days or two months following the last exposure. Three days following the last repeated chlorpyrifos exposure, there were transient effects in open-field motor activity and plasma cholinesterase activity levels. Two months following the chlorpyrifos exposures, there were delayed effects in sensorimotor gating, pro-inflammatory cytokines and spinal lumbar motoneuron soma morphology. Overall, these results offer support that subacute repeated occupational-like chlorpyrifos exposures have both short-term and longer-term effects in motor activity, inflammation, and central nervous system mechanisms.
Collapse
Affiliation(s)
- Shannon H Romer
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Leidos, Reston, VA, United States of America
| | - Kaitlyn M Miller
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States of America
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, United States of America
| | - Martha J Sonner
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Leidos, Reston, VA, United States of America
| | - Victoria T Ethridge
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
- Leidos, Reston, VA, United States of America
| | - Nathan M Gargas
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
| | - Joyce G Rohan
- Environmental Health Effects Laboratory, Naval Medical Research Unit Dayton, Wright-Patterson AFB, Dayton, OH, United States of America
| |
Collapse
|
2
|
Mesquida-Veny F, Martínez-Torres S, Del Río JA, Hervera A. Genetic control of neuronal activity enhances axonal growth only on permissive substrates. Mol Med 2022; 28:97. [PMID: 35978278 PMCID: PMC9387030 DOI: 10.1186/s10020-022-00524-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 08/03/2022] [Indexed: 11/19/2022] Open
Abstract
Background Neural tissue has limited regenerative ability. To cope with that, in recent years a diverse set of novel tools has been used to tailor neurostimulation therapies and promote functional regeneration after axonal injuries. Method In this report, we explore cell-specific methods to modulate neuronal activity, including opto- and chemogenetics to assess the effect of specific neuronal stimulation in the promotion of axonal regeneration after injury. Results Opto- and chemogenetic stimulations of neuronal activity elicited increased in vitro neurite outgrowth in both sensory and cortical neurons, as well as in vivo regeneration in the sciatic nerve, but not after spinal cord injury. Mechanistically, inhibitory substrates such as chondroitin sulfate proteoglycans block the activity induced increase in axonal growth. Conclusions We found that genetic modulations of neuronal activity on both dorsal root ganglia and corticospinal motor neurons increase their axonal growth capacity but only on permissive environments. Supplementary Information The online version contains supplementary material available at 10.1186/s10020-022-00524-2.
Collapse
Affiliation(s)
- Francina Mesquida-Veny
- Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.,Department of Cell Biology, Physiology and Immunology, University of Barcelona, Barcelona, Spain.,Network Centre of Biomedical Research of Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Ministry of Economy and Competitiveness, Madrid, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Sara Martínez-Torres
- Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.,Department of Cell Biology, Physiology and Immunology, University of Barcelona, Barcelona, Spain.,Network Centre of Biomedical Research of Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Ministry of Economy and Competitiveness, Madrid, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - José Antonio Del Río
- Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain.,Department of Cell Biology, Physiology and Immunology, University of Barcelona, Barcelona, Spain.,Network Centre of Biomedical Research of Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Ministry of Economy and Competitiveness, Madrid, Spain.,Institute of Neuroscience, University of Barcelona, Barcelona, Spain
| | - Arnau Hervera
- Molecular and Cellular Neurobiotechnology, Institute for Bioengineering of Catalonia (IBEC), Barcelona, Spain. .,Department of Cell Biology, Physiology and Immunology, University of Barcelona, Barcelona, Spain. .,Network Centre of Biomedical Research of Neurodegenerative Diseases (CIBERNED), Institute of Health Carlos III, Ministry of Economy and Competitiveness, Madrid, Spain. .,Institute of Neuroscience, University of Barcelona, Barcelona, Spain.
| |
Collapse
|
3
|
Deardorff AS, Romer SH, Fyffe RE. Location, location, location: the organization and roles of potassium channels in mammalian motoneurons. J Physiol 2021; 599:1391-1420. [DOI: 10.1113/jp278675] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 01/08/2021] [Indexed: 11/08/2022] Open
Affiliation(s)
- Adam S. Deardorff
- Department of Neuroscience, Cell Biology and Physiology, Wright State University Boonshoft School of Medicine Dayton OH 45435 USA
- Department of Neurology and Internal Medicine, Wright State University Boonshoft School of Medicine Dayton OH 45435 USA
| | - Shannon H. Romer
- Odyssey Systems Environmental Health Effects Laboratory, Navy Medical Research Unit‐Dayton Wright‐Patterson Air Force Base OH 45433 USA
| | - Robert E.W. Fyffe
- Department of Neuroscience, Cell Biology and Physiology, Wright State University Boonshoft School of Medicine Dayton OH 45435 USA
| |
Collapse
|
4
|
Antispasmodic Drug Drofenine as an Inhibitor of Kv2.1 Channel Ameliorates Peripheral Neuropathy in Diabetic Mice. iScience 2020; 23:101617. [PMID: 33089105 PMCID: PMC7559245 DOI: 10.1016/j.isci.2020.101617] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 07/22/2020] [Accepted: 09/23/2020] [Indexed: 12/30/2022] Open
Abstract
Diabetic peripheral neuropathy (DPN) is a common diabetic complication and has yet no efficient medication. Here, we report that antispasmodic drug drofenine (Dfe) blocks Kv2.1 and ameliorates DPN-like pathology in diabetic mice. The underlying mechanisms are investigated against the DPN mice with in vivo Kv2.1 knockdown through adeno associated virus AAV9-Kv2.1-RNAi. Streptozotocin (STZ) induced type 1 or db/db type 2 diabetic mice with DPN exhibited a high level of Kv2.1 protein in dorsal root ganglion (DRG) tissue and a suppressed neurite outgrowth in DRG neuron. Dfe promoted neurite outgrowth by inhibiting Kv2.1 channel and/or Kv2.1 mRNA and protein expression level. Moreover, it suppressed inflammation by repressing IκBα/NF-κB signaling, inhibited apoptosis by regulating Kv2.1-mediated Bcl-2 family proteins and Caspase-3 and ameliorated mitochondrial dysfunction through Kv2.1/CaMKKβ/AMPK/PGC1α pathway. Our work supports that Kv2.1 inhibition is a promisingly therapeutic strategy for DPN and highlights the potential of Dfe in treating this disease. Antispasmodic drug drofenine (Dfe) ameliorates DPN-like pathology in diabetic mice Dfe inhibits Kv2.1 channel and/or Kv2.1 mRNA and protein expression level Dfe represses inflammation, apoptosis, and mitochondrial dysfunction in DPN mice Kv2.1 inhibition is a therapeutic tactic and Dfe shows therapeutic potential for DPN
Collapse
|
5
|
Aagaard P, Bojsen-Møller J, Lundbye-Jensen J. Assessment of Neuroplasticity With Strength Training. Exerc Sport Sci Rev 2020; 48:151-162. [DOI: 10.1249/jes.0000000000000229] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
6
|
Nascimento F, Broadhead MJ, Tetringa E, Tsape E, Zagoraiou L, Miles GB. Synaptic mechanisms underlying modulation of locomotor-related motoneuron output by premotor cholinergic interneurons. eLife 2020; 9:e54170. [PMID: 32081133 PMCID: PMC7062467 DOI: 10.7554/elife.54170] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/20/2020] [Indexed: 01/15/2023] Open
Abstract
Spinal motor networks are formed by diverse populations of interneurons that set the strength and rhythmicity of behaviors such as locomotion. A small cluster of cholinergic interneurons, expressing the transcription factor Pitx2, modulates the intensity of muscle activation via 'C-bouton' inputs to motoneurons. However, the synaptic mechanisms underlying this neuromodulation remain unclear. Here, we confirm in mice that Pitx2+ interneurons are active during fictive locomotion and that their chemogenetic inhibition reduces the amplitude of motor output. Furthermore, after genetic ablation of cholinergic Pitx2+ interneurons, M2 receptor-dependent regulation of the intensity of locomotor output is lost. Conversely, chemogenetic stimulation of Pitx2+ interneurons leads to activation of M2 receptors on motoneurons, regulation of Kv2.1 channels and greater motoneuron output due to an increase in the inter-spike afterhyperpolarization and a reduction in spike half-width. Our findings elucidate synaptic mechanisms by which cholinergic spinal interneurons modulate the final common pathway for motor output.
Collapse
Affiliation(s)
- Filipe Nascimento
- School of Psychology and Neuroscience, University of St AndrewsSt AndrewsUnited Kingdom
| | | | - Efstathia Tetringa
- Center of Basic Research, Biomedical Research Foundation of the Academy of AthensAthensGreece
| | - Eirini Tsape
- Center of Basic Research, Biomedical Research Foundation of the Academy of AthensAthensGreece
| | - Laskaro Zagoraiou
- Center of Basic Research, Biomedical Research Foundation of the Academy of AthensAthensGreece
| | - Gareth Brian Miles
- School of Psychology and Neuroscience, University of St AndrewsSt AndrewsUnited Kingdom
| |
Collapse
|
7
|
Johnson B, Leek AN, Tamkun MM. Kv2 channels create endoplasmic reticulum / plasma membrane junctions: a brief history of Kv2 channel subcellular localization. Channels (Austin) 2019; 13:88-101. [PMID: 30712450 PMCID: PMC6380216 DOI: 10.1080/19336950.2019.1568824] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The potassium channels Kv2.1 and Kv2.2 are widely expressed throughout the mammalian brain. Kv2.1 provides the majority of delayed rectifying current in rat hippocampus while both channels are differentially expressed in cortex. Particularly unusual is their neuronal surface localization pattern: while half the channel population is freely-diffusive on the plasma membrane as expected from the generalized Singer & Nicolson fluid mosaic model, the other half localizes into micron-sized clusters on the soma, dendrites, and axon initial segment. These clusters contain hundreds of channels, which for Kv2.1, are largely non-conducting. Competing theories of the mechanism underlying Kv2.1 clustering have included static tethering to being corralled by an actin fence. Now, recent work has demonstrated channel clustering is due to formation of endoplasmic reticulum/plasma membrane (ER/PM) junctions through interaction with ER-resident VAMP-associated proteins (VAPs). Interaction between surface Kv2 channels and ER VAPs groups channels together in clusters. ER/PM junctions play important roles in inter-organelle communication: they regulate ion flux, are involved in lipid transfer, and are sites of endo- and exocytosis. Kv2-induced ER/PM junctions are regulated through phosphorylation of the channel C-terminus which in turn regulates VAP binding, providing a rapid means to create or dismantle these microdomains. In addition, insults such as hypoxia or ischemia disrupt this interaction resulting in ER/PM junction disassembly. Kv2 channels are the only known plasma membrane protein to form regulated, injury sensitive junctions in this manner. Furthermore, it is likely that concentrated VAPs at these microdomains sequester additional interactors whose functions are not yet fully understood.
Collapse
Affiliation(s)
- Ben Johnson
- a Molecular, Cellular and Integrative Neurosciences Graduate Program , Colorado State University , Fort Collins , CO , USA.,b Department of Biomedical Sciences , Colorado State University , Fort Collins , CO , USA
| | - Ashley N Leek
- a Molecular, Cellular and Integrative Neurosciences Graduate Program , Colorado State University , Fort Collins , CO , USA.,b Department of Biomedical Sciences , Colorado State University , Fort Collins , CO , USA
| | - Michael M Tamkun
- a Molecular, Cellular and Integrative Neurosciences Graduate Program , Colorado State University , Fort Collins , CO , USA.,b Department of Biomedical Sciences , Colorado State University , Fort Collins , CO , USA.,c Department of Biochemistry and Molecular Biology , Colorado State University , Fort Collins , CO , USA
| |
Collapse
|
8
|
Ciotu CI, Tsantoulas C, Meents J, Lampert A, McMahon SB, Ludwig A, Fischer MJM. Noncanonical Ion Channel Behaviour in Pain. Int J Mol Sci 2019; 20:E4572. [PMID: 31540178 PMCID: PMC6770626 DOI: 10.3390/ijms20184572] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 12/19/2022] Open
Abstract
Ion channels contribute fundamental properties to cell membranes. Although highly diverse in conductivity, structure, location, and function, many of them can be regulated by common mechanisms, such as voltage or (de-)phosphorylation. Primarily considering ion channels involved in the nociceptive system, this review covers more novel and less known features. Accordingly, we outline noncanonical operation of voltage-gated sodium, potassium, transient receptor potential (TRP), and hyperpolarization-activated cyclic nucleotide (HCN)-gated channels. Noncanonical features discussed include properties as a memory for prior voltage and chemical exposure, alternative ion conduction pathways, cluster formation, and silent subunits. Complementary to this main focus, the intention is also to transfer knowledge between fields, which become inevitably more separate due to their size.
Collapse
Affiliation(s)
- Cosmin I Ciotu
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Jannis Meents
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Angelika Lampert
- Institute of Physiology, University Hospital RWTH Aachen, 52074 Aachen, Germany
| | - Stephen B McMahon
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UR, UK
| | - Andreas Ludwig
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Michael J M Fischer
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
| |
Collapse
|
9
|
Romer SH, Deardorff AS, Fyffe REW. A molecular rheostat: Kv2.1 currents maintain or suppress repetitive firing in motoneurons. J Physiol 2019; 597:3769-3786. [DOI: 10.1113/jp277833] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 05/29/2019] [Indexed: 12/26/2022] Open
Affiliation(s)
- Shannon H. Romer
- Neuroscience, Cell Biology & PhysiologyBoonshoft School of MedicineWright State University Fairborn OH 45435 USA
- Oak Ridge Institute for Science and EducationEnvironmental Health Effects LaboratoryNavy Medical Research Unit‐DaytonWright‐Patterson Air Force Base OH 45433 USA
| | - Adam S. Deardorff
- Neuroscience, Cell Biology & PhysiologyBoonshoft School of MedicineWright State University Fairborn OH 45435 USA
- Neurology, Boonshoft School of MedicineWright State University Dayton OH 45409 USA
| | - Robert E. W. Fyffe
- Neuroscience, Cell Biology & PhysiologyBoonshoft School of MedicineWright State University Fairborn OH 45435 USA
| |
Collapse
|
10
|
Modulator-Gated, SUMOylation-Mediated, Activity-Dependent Regulation of Ionic Current Densities Contributes to Short-Term Activity Homeostasis. J Neurosci 2018; 39:596-611. [PMID: 30504282 DOI: 10.1523/jneurosci.1379-18.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 10/23/2018] [Accepted: 11/03/2018] [Indexed: 02/07/2023] Open
Abstract
Neurons operate within defined activity limits, and feedback control mechanisms dynamically tune ionic currents to maintain this optimal range. This study describes a novel, rapid feedback mechanism that uses SUMOylation to continuously adjust ionic current densities according to changes in activity. Small ubiquitin-like modifier (SUMO) is a peptide that can be post-translationally conjugated to ion channels to influence their surface expression and biophysical properties. Neuronal activity can regulate the extent of protein SUMOylation. This study on the single, unambiguously identifiable lateral pyloric neuron (LP), a component of the pyloric network in the stomatogastric nervous system of male and female spiny lobsters (Panulirus interruptus), focused on dynamic SUMOylation in the context of activity homeostasis. There were four major findings: First, neuronal activity adjusted the balance between SUMO conjugation and deconjugation to continuously and bidirectionally fine-tune the densities of two opposing conductances: the hyperpolarization activated current (Ih) and the transient potassium current (IA). Second, tonic 5 nm dopamine (DA) gated activity-dependent SUMOylation to permit and prevent activity-dependent regulation of Ih and IA, respectively. Third, DA-gated, activity-dependent SUMOylation contributed to a feedback mechanism that restored the timing and duration of LP activity during prolonged modulation by 5 μm DA, which initially altered these and other activity features. Fourth, DA modulatory and metamoduatory (gating) effects were tailored to simultaneously alter and stabilize neuronal output. Our findings suggest that modulatory tone may select a subset of rapid activity-dependent mechanisms from a larger menu to achieve homeostasis under varying conditions.SIGNIFICANCE STATEMENT Post-translational SUMOylation of ion channel subunits controls their interactions. When subunit SUMOylation is dysregulated, conductance densities mediated by the channels are distorted, leading to nervous system disorders, such as seizures and chronic pain. Regulation of ion channel SUMOylation is poorly understood. This study demonstrated that neuronal activity can regulate SUMOylation to reconfigure ionic current densities over minutes, and this regulation was gated by tonic nanomolar dopamine. Dynamic SUMOylation was necessary to maintain specific aspects of neuronal output while the neuron was being modulated by high (5 μm) concentrations of dopamine, suggesting that the gating function may ensure neuronal homeostasis during extrinsic modulation of a circuit.
Collapse
|
11
|
Kv2 potassium channels form endoplasmic reticulum/plasma membrane junctions via interaction with VAPA and VAPB. Proc Natl Acad Sci U S A 2018; 115:E7331-E7340. [PMID: 29941597 DOI: 10.1073/pnas.1805757115] [Citation(s) in RCA: 112] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Kv2.1 exhibits two distinct forms of localization patterns on the neuronal plasma membrane: One population is freely diffusive and regulates electrical activity via voltage-dependent K+ conductance while a second one localizes to micrometer-sized clusters that contain densely packed, but nonconducting, channels. We have previously established that these clusters represent endoplasmic reticulum/plasma membrane (ER/PM) junctions that function as membrane trafficking hubs and that Kv2.1 plays a structural role in forming these membrane contact sites in both primary neuronal cultures and transfected HEK cells. Clustering and the formation of ER/PM contacts are regulated by phosphorylation within the channel C terminus, offering cells fast, dynamic control over the physical relationship between the cortical ER and PM. The present study addresses the mechanisms by which Kv2.1 and the related Kv2.2 channel interact with the ER membrane. Using proximity-based biotinylation techniques in transfected HEK cells we identified ER VAMP-associated proteins (VAPs) as potential Kv2.1 interactors. Confirmation that Kv2.1 and -2.2 bind VAPA and VAPB employed colocalization/redistribution, siRNA knockdown, and Förster resonance energy transfer (FRET)-based assays. CD4 chimeras containing sequence from the Kv2.1 C terminus were used to identify a noncanonical VAP-binding motif. VAPs were first identified as proteins required for neurotransmitter release in Aplysia and are now known to be abundant scaffolding proteins involved in membrane contact site formation throughout the ER. The VAP interactome includes AKAPs, kinases, membrane trafficking machinery, and proteins regulating nonvesicular lipid transport from the ER to the PM. Therefore, the Kv2-induced VAP concentration at ER/PM contact sites is predicted to have wide-ranging effects on neuronal cell biology.
Collapse
|