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OIsen T, Capurro A, Švent M, Pilati N, Large C, Hartell N, Hamann M. Sparsely Distributed, Pre-synaptic Kv3 K + Channels Control Spontaneous Firing and Cross-Unit Synchrony via the Regulation of Synaptic Noise in an Auditory Brainstem Circuit. Front Cell Neurosci 2021; 15:721371. [PMID: 34539351 PMCID: PMC8446535 DOI: 10.3389/fncel.2021.721371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Accepted: 08/02/2021] [Indexed: 11/13/2022] Open
Abstract
Spontaneous subthreshold activity in the central nervous system is fundamental to information processing and transmission, as it amplifies and optimizes sub-threshold signals, thereby improving action potential initiation and maintaining reliable firing. This form of spontaneous activity, which is frequently considered noise, is particularly important at auditory synapses where acoustic information is encoded by rapid and temporally precise firing rates. In contrast, when present in excess, this form of noise becomes detrimental to acoustic information as it contributes to the generation and maintenance of auditory disorders such as tinnitus. The most prominent contribution to subthreshold noise is spontaneous synaptic transmission (synaptic noise). Although numerous studies have examined the role of synaptic noise on single cell excitability, little is known about its pre-synaptic modulation owing in part to the difficulties of combining noise modulation with monitoring synaptic release. Here we study synaptic noise in the auditory brainstem dorsal cochlear nucleus (DCN) of mice and show that pharmacological potentiation of Kv3 K+ currents reduces the level of synaptic bombardment onto DCN principal fusiform cells. Using a transgenic mouse line (SyG37) expressing SyGCaMP2-mCherry, a calcium sensor that targets pre-synaptic terminals, we show that positive Kv3 K+ current modulation decreases calcium influx in a fifth of pre-synaptic boutons. Furthermore, while maintaining rapid and precise spike timing, positive Kv3 K+ current modulation increases the synchronization of local circuit neurons by reducing spontaneous activity. In conclusion, our study identifies a unique pre-synaptic mechanism which reduces synaptic noise at auditory synapses and contributes to the coherent activation of neurons in a local auditory brainstem circuit. This form of modulation highlights a new therapeutic target, namely the pre-synaptic bouton, for ameliorating the effects of hearing disorders which are dependent on aberrant spontaneous activity within the central auditory system.
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Affiliation(s)
- Timothy OIsen
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom.,Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, San Francisco, CA, United States
| | - Alberto Capurro
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom.,Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Maša Švent
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom
| | | | - Charles Large
- Autifony Therapeutics Limited, Stevenage Bioscience Catalyst, Stevenage, United Kingdom
| | - Nick Hartell
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom
| | - Martine Hamann
- Department of Neuroscience, Psychology and Behaviour, College of Life Sciences, University of Leicester, Leicester, United Kingdom.,Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
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Broussard GJ, Petreanu L. Eavesdropping wires: Recording activity in axons using genetically encoded calcium indicators. J Neurosci Methods 2021; 360:109251. [PMID: 34119572 PMCID: PMC8363211 DOI: 10.1016/j.jneumeth.2021.109251] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/31/2021] [Accepted: 06/05/2021] [Indexed: 12/23/2022]
Abstract
Neurons broadcast electrical signals to distal brain regions through extensive axonal arbors. Genetically encoded calcium sensors permit the direct observation of action potential activity at axonal terminals, providing unique insights on the organization and function of neural projections. Here, we consider what information can be gleaned from axonal recordings made at scales ranging from the summed activity extracted from multi-cell axon projections to single boutons. In particular, we discuss the application of different recently developed multi photon and fiber photometry methods for recording neural activity in axons of rodents. We define experimental difficulties associated with imaging approaches in the axonal compartment and highlight the latest methodological advances for addressing these issues. Finally, we reflect on ways in which new technologies can be used in conjunction with axon calcium imaging to address current questions in neurobiology.
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Affiliation(s)
| | - Leopoldo Petreanu
- Champalimaud Research, Champalimaud Center for the Unknown, Lisbon, Portugal.
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Gupte TM, Ritt M, Sivaramakrishnan S. ER/K-link-Leveraging a native protein linker to probe dynamic cellular interactions. Methods Enzymol 2020; 647:173-208. [PMID: 33482988 PMCID: PMC8009693 DOI: 10.1016/bs.mie.2020.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
ER/K α-helices are a subset of single alpha helical domains, which exhibit unusual stability as isolated protein secondary structures. They adopt an elongated structural conformation, while regulating the frequency of interactions between proteins or polypeptides fused to their ends. Here we review recent advances on the structure, stability and function of ER/K α-helices as linkers (ER/K linkers) in native proteins. We describe methodological considerations in the molecular cloning, protein expression and measurement of interaction strengths, using sensors incorporating ER/K linkers. We highlight biological insights obtained over the last decade by leveraging distinct biophysical features of ER/K-linked sensors. We conclude with the outlook for the use of ER/K linkers in the selective modulation of dynamic cellular interactions.
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Affiliation(s)
- Tejas M Gupte
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States.
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Kostyuk AI, Kokova AD, Podgorny OV, Kelmanson IV, Fetisova ES, Belousov VV, Bilan DS. Genetically Encoded Tools for Research of Cell Signaling and Metabolism under Brain Hypoxia. Antioxidants (Basel) 2020; 9:E516. [PMID: 32545356 PMCID: PMC7346190 DOI: 10.3390/antiox9060516] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 06/04/2020] [Accepted: 06/06/2020] [Indexed: 02/08/2023] Open
Abstract
Hypoxia is characterized by low oxygen content in the tissues. The central nervous system (CNS) is highly vulnerable to a lack of oxygen. Prolonged hypoxia leads to the death of brain cells, which underlies the development of many pathological conditions. Despite the relevance of the topic, different approaches used to study the molecular mechanisms of hypoxia have many limitations. One promising lead is the use of various genetically encoded tools that allow for the observation of intracellular parameters in living systems. In the first part of this review, we provide the classification of oxygen/hypoxia reporters as well as describe other genetically encoded reporters for various metabolic and redox parameters that could be implemented in hypoxia studies. In the second part, we discuss the advantages and disadvantages of the primary hypoxia model systems and highlight inspiring examples of research in which these experimental settings were combined with genetically encoded reporters.
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Affiliation(s)
- Alexander I. Kostyuk
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.D.K.); (O.V.P.); (I.V.K.); (E.S.F.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Aleksandra D. Kokova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.D.K.); (O.V.P.); (I.V.K.); (E.S.F.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Oleg V. Podgorny
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.D.K.); (O.V.P.); (I.V.K.); (E.S.F.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
- Koltzov Institute of Developmental Biology, 119334 Moscow, Russia
| | - Ilya V. Kelmanson
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.D.K.); (O.V.P.); (I.V.K.); (E.S.F.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
| | - Elena S. Fetisova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.D.K.); (O.V.P.); (I.V.K.); (E.S.F.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
- Faculty of Biology, Lomonosov Moscow State University, 119992 Moscow, Russia
| | - Vsevolod V. Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.D.K.); (O.V.P.); (I.V.K.); (E.S.F.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
- Institute for Cardiovascular Physiology, Georg August University Göttingen, D-37073 Göttingen, Germany
- Federal Center for Cerebrovascular Pathology and Stroke, 117997 Moscow, Russia
| | - Dmitry S. Bilan
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, 117997 Moscow, Russia; (A.I.K.); (A.D.K.); (O.V.P.); (I.V.K.); (E.S.F.); (V.V.B.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, 117997 Moscow, Russia
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Pereda D, Al‐Osta I, Okorocha AE, Easton A, Hartell NA. Changes in presynaptic calcium signalling accompany age-related deficits in hippocampal LTP and cognitive impairment. Aging Cell 2019; 18:e13008. [PMID: 31310431 PMCID: PMC6718530 DOI: 10.1111/acel.13008] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 06/10/2019] [Accepted: 06/26/2019] [Indexed: 11/27/2022] Open
Abstract
The loss of cognitive function accompanying healthy aging is not associated with extensive or characteristic patterns of cell death, suggesting it is caused by more subtle changes in synaptic properties. In the hippocampal CA1 region, long‐term potentiation requires stronger stimulation for induction in aged rats and mice and long‐term depression becomes more prevalent. An age‐dependent impairment of postsynaptic calcium homeostasis may underpin these effects. We have examined changes in presynaptic calcium signalling in aged mice using a transgenic mouse line (SyG37) that expresses a genetically encoded calcium sensor in presynaptic terminals. SyG37 mice showed an age‐dependent decline in cognitive abilities in behavioural tasks that require hippocampal processing including the Barnes maze, T‐maze and object location but not recognition tests. The incidence of LTP was significantly impaired in animals over 18 months of age. These effects of aging were accompanied by a persistent increase in resting presynaptic calcium, an increase in the presynaptic calcium signal following Schaffer collateral fibre stimulation, an increase in postsynaptic fEPSP slope and a reduction in paired‐pulse facilitation. These effects were not caused by synapse proliferation and were of presynaptic origin since they were evident in single presynaptic boutons. Aged synapses behaved like younger ones when the extracellular calcium concentration was reduced. Raising extracellular calcium had little effect on aged synapses but altered the properties of young synapses into those of their aged counterparts. These effects can be readily explained by an age‐dependent change in the properties or numbers of presynaptic calcium channels.
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Affiliation(s)
- Daniel Pereda
- Department of Neuroscience, Psychology and Behaviour University of Leicester Leicester UK
| | - Ibrahim Al‐Osta
- Department of Neuroscience, Psychology and Behaviour University of Leicester Leicester UK
| | - Albert E. Okorocha
- Department of Neuroscience, Psychology and Behaviour University of Leicester Leicester UK
| | | | - Nicholas A. Hartell
- Department of Neuroscience, Psychology and Behaviour University of Leicester Leicester UK
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Yu J, Kwon H, Cho E, Jeon J, Kang RH, Youn K, Jun M, Lee YC, Ryu JH, Kim DH. The effects of pinoresinol on cholinergic dysfunction-induced memory impairments and synaptic plasticity in mice. Food Chem Toxicol 2019; 125:376-382. [PMID: 30685474 DOI: 10.1016/j.fct.2019.01.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/02/2019] [Accepted: 01/17/2019] [Indexed: 12/28/2022]
Abstract
Dementia is a category of brain diseases that cause a decrease in cognitive functions. Alzheimer's disease (AD) is the most frequently mentioned neurodegenerative disease showing dementia. Although many useful drugs for dementia were developed, we still need better and safer drugs. Here, we tested pinoresinol, a lignan found in sesame seed and olive oil, whether it could be a candidate for this purpose. Pinoresinol (25 mg/kg, p.o.) ameliorated memory impairment in dementia model induced by cholinergic blockade in the passive avoidance test in a dose-dependent manner. Moreover, pinoresinol (50 μM) facilitated induction of hippocampal long-term potentiation, a cellular model of learning and memory. Pinoresinol blocked acetylcholinesterase (AchE), an acetylcholine-degrading enzyme, activity in a concentration-dependent manner. Moreover, pinoresinol (50 μM) facilitated calcium influx into neuro2a cell. These results suggest that pinoresinol improves memory impairment and facilitates hippocampal LTP induction and these results might be related to the effect of pinoresinol on AChE and calcium influx.
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Affiliation(s)
- Jimin Yu
- Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 49315, Republic of Korea
| | - Huiyoung Kwon
- Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 49315, Republic of Korea
| | - Eunbi Cho
- Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 49315, Republic of Korea
| | - Jieun Jeon
- Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 49315, Republic of Korea
| | - Rae Hee Kang
- Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 49315, Republic of Korea
| | - Kumju Youn
- Department of Food Science and Nutrition, Dong-A University, Busan, 49315, Republic of Korea
| | - Mira Jun
- Department of Food Science and Nutrition, Dong-A University, Busan, 49315, Republic of Korea; Institute of Convergence Bio-Health, Dong-A University, Busan, 49315, Republic of Korea
| | - Young Choon Lee
- Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 49315, Republic of Korea; Institute of Convergence Bio-Health, Dong-A University, Busan, 49315, Republic of Korea
| | - Jong Hoon Ryu
- Department of Oriental Pharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul, 02447, Republic of Korea
| | - Dong Hyun Kim
- Department of Medicinal Biotechnology, College of Health Sciences, Dong-A University, Busan, 49315, Republic of Korea; Institute of Convergence Bio-Health, Dong-A University, Busan, 49315, Republic of Korea.
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