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Bargary G, Bosten JM, Lawrance-Owen AJ, Goodbourn PT, Mollon JD. Evidence for an Association Between a pH-Dependent Potassium Channel, TWIK-1, and the Accuracy of Smooth Pursuit Eye Movements. Invest Ophthalmol Vis Sci 2024; 65:24. [PMID: 39012638 PMCID: PMC11257018 DOI: 10.1167/iovs.65.8.24] [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: 02/16/2024] [Accepted: 06/06/2024] [Indexed: 07/17/2024] Open
Abstract
Purpose Within the healthy population there is a large variation in the ability to perform smooth pursuit eye movements. Our purpose was to investigate the genetic and physiological bases for this variation. Methods We carried out a whole-genome association study, recording smooth pursuit movements for 1040 healthy volunteers by infrared oculography. The primary phenotypic measure was root mean square error (RMSE) of eye position relative to target position. Secondary measures were pursuit gain, frequency of catch-up saccades, and frequency of anticipatory saccades. Ten percent of participants, chosen randomly, were tested twice, giving estimates of test-retest reliability. Results No significant association was found with three genes previously identified as candidate genes for variation in smooth pursuit: DRD3, COMT, NRG1. A strong association (P = 3.55 × 10-11) was found between RMSE and chromosomal region 1q42.2. The most strongly associated marker (rs701232) lies in an intron of KCNK1, which encodes a two-pore-domain potassium ion channel TWIK-1 (or K2P1) that affects cell excitability. Each additional copy of the A allele decreased RMSE by 0.29 standard deviation. When a psychophysical test of visually perceived motion was used as a covariate in the regression analysis, the association with rs701232 did not weaken (P = 5.38 × 10-12). Conclusions Variation in the sequence or the expression of the pH-dependent ion channel TWIK-1 is a likely source of variance in smooth pursuit. The variance associated with TWIK-1 appears not to arise from sensory mechanisms, because the use of a perceptual covariate left the association intact.
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Affiliation(s)
- Gary Bargary
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, United Kingdom
- Department of Optometry and Visual Science, City University London, Northampton Square, London, United Kingdom
| | - Jenny M. Bosten
- School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Adam J. Lawrance-Owen
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, United Kingdom
| | - Patrick T. Goodbourn
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, United Kingdom
- School of Psychological Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Victoria, Australia
| | - John D. Mollon
- Department of Psychology, University of Cambridge, Downing Street, Cambridge, United Kingdom
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Kim SS, Bae Y, Kwon O, Kwon SH, Seo JB, Hwang EM, Park JY. β-COP Regulates TWIK1/TREK1 Heterodimeric Channel-Mediated Passive Conductance in Astrocytes. Cells 2022; 11:cells11203322. [PMID: 36291187 PMCID: PMC9600989 DOI: 10.3390/cells11203322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/16/2022] [Accepted: 10/19/2022] [Indexed: 11/16/2022] Open
Abstract
Mature astrocytes are characterized by a K+ conductance (passive conductance) that changes with a constant slope with voltage, which is involved in K+ homeostasis in the brain. Recently, we reported that the tandem of pore domains in a weak inward rectifying K+ channel (TWIK1 or KCNK1) and TWIK-related K+ channel 1 (TREK1 or KCNK2) form heterodimeric channels that mediate passive conductance in astrocytes. However, little is known about the binding proteins that regulate the function of the TWIK1/TREK1 heterodimeric channels. Here, we found that β-coat protein (COP) regulated the surface expression and activity of the TWIK1/TREK1 heterodimeric channels in astrocytes. β-COP binds directly to TREK1 but not TWIK1 in a heterologous expression system. However, β-COP also interacts with the TWIK1/TREK1 heterodimeric channel in a TREK1 dependent manner and enhances the surface expression of the heterodimeric channel in astrocytes. Consequently, it regulates TWIK1/TREK1 heterodimeric channel-mediated passive conductance in astrocytes in the mouse brain. Taken together, these results suggest that β-COP is a potential regulator of astrocytic passive conductance in the brain.
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Affiliation(s)
- Seong-Seop Kim
- School of Biosystems and Biomedical Sciences, College of Health Sciences, Korea University, Seoul 02841, Korea
| | - Yeonju Bae
- School of Biosystems and Biomedical Sciences, College of Health Sciences, Korea University, Seoul 02841, Korea
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Osung Kwon
- School of Biosystems and Biomedical Sciences, College of Health Sciences, Korea University, Seoul 02841, Korea
| | - Seung-Hae Kwon
- Seoul Center, Korea Basic Science Institute (KBSI), Seoul 02841, Korea
| | - Jong Bok Seo
- Seoul Center, Korea Basic Science Institute (KBSI), Seoul 02841, Korea
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Jae-Yong Park
- School of Biosystems and Biomedical Sciences, College of Health Sciences, Korea University, Seoul 02841, Korea
- Correspondence: ; Tel.: +82-2-3290-5637
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Kwon O, Yang H, Kim SC, Kim J, Sim J, Lee J, Hwang EM, Shim S, Park JY. TWIK-1 BAC-GFP Transgenic Mice, an Animal Model for TWIK-1 Expression. Cells 2021; 10:cells10102751. [PMID: 34685731 PMCID: PMC8534699 DOI: 10.3390/cells10102751] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/26/2021] [Accepted: 10/11/2021] [Indexed: 12/15/2022] Open
Abstract
TWIK-1 is the first identified member of the two-pore domain potassium (K2P) channels that are involved in neuronal excitability and astrocytic passive conductance in the brain. Despite the physiological roles of TWIK-1, there is still a lack of information on the basic expression patterns of TWIK-1 proteins in the brain. Here, using a modified bacterial artificial chromosome (BAC), we generated a transgenic mouse (Tg mouse) line expressing green fluorescent protein (GFP) under the control of the TWIK-1 promoter (TWIK-1 BAC-GFP Tg mice). We confirmed that nearly all GFP-producing cells co-expressed endogenous TWIK-1 in the brain of TWIK-1 BAC-GFP Tg mice. GFP signals were highly expressed in various brain areas, including the dentate gyrus (DG), lateral entorhinal cortex (LEC), and cerebellum (Cb). In addition, we found that GFP signals were highly expressed in immature granule cells in the DG. Finally, our TWIK-1 BAC-GFP Tg mice mimic the upregulation of TWIK-1 mRNA expression in the hippocampus following the injection of kainic acid (KA). Our data clearly showed that TWIK-1 BAC-GFP Tg mice are a useful animal model for studying the mechanisms regulating TWIK-1 gene expression and the physiological roles of TWIK-1 channels in the brain.
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Affiliation(s)
- Osung Kwon
- Department of Integrated Biomedical and Life Science, Graduate School, Jiyoun Lee Korea University, Seoul 02841, Korea; (O.K.); (S.-C.K.); (J.K.); (J.S.); (J.L.)
| | - Hayoung Yang
- Department of Biochemistry, Chungbuk National University, Cheongju 28644, Korea;
| | - Seung-Chan Kim
- Department of Integrated Biomedical and Life Science, Graduate School, Jiyoun Lee Korea University, Seoul 02841, Korea; (O.K.); (S.-C.K.); (J.K.); (J.S.); (J.L.)
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea;
| | - Juhyun Kim
- Department of Integrated Biomedical and Life Science, Graduate School, Jiyoun Lee Korea University, Seoul 02841, Korea; (O.K.); (S.-C.K.); (J.K.); (J.S.); (J.L.)
- BK21FOUR R&E Center for Learning Health Systems, Korea University, Seoul 02841, Korea
| | - Jaewon Sim
- Department of Integrated Biomedical and Life Science, Graduate School, Jiyoun Lee Korea University, Seoul 02841, Korea; (O.K.); (S.-C.K.); (J.K.); (J.S.); (J.L.)
| | - Jiyoun Lee
- Department of Integrated Biomedical and Life Science, Graduate School, Jiyoun Lee Korea University, Seoul 02841, Korea; (O.K.); (S.-C.K.); (J.K.); (J.S.); (J.L.)
- BK21FOUR R&E Center for Learning Health Systems, Korea University, Seoul 02841, Korea
| | - Eun-Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea;
| | - Sungbo Shim
- Department of Biochemistry, Chungbuk National University, Cheongju 28644, Korea;
- Correspondence: (S.S.); (J.-Y.P.)
| | - Jae-Yong Park
- Department of Integrated Biomedical and Life Science, Graduate School, Jiyoun Lee Korea University, Seoul 02841, Korea; (O.K.); (S.-C.K.); (J.K.); (J.S.); (J.L.)
- Correspondence: (S.S.); (J.-Y.P.)
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Chronic sleep fragmentation enhances habenula cholinergic neural activity. Mol Psychiatry 2021; 26:941-954. [PMID: 30980042 PMCID: PMC6790161 DOI: 10.1038/s41380-019-0419-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 02/21/2019] [Accepted: 03/26/2019] [Indexed: 01/25/2023]
Abstract
Sleep is essential to emotional health. Sleep disturbance, particularly REM sleep disturbance, profoundly impacts emotion regulation, but the underlying neural mechanisms remain elusive. Here we show that chronic REM sleep disturbance, achieved in mice by chronic sleep fragmentation (SF), enhanced neural activity in the medial habenula (mHb), a brain region increasingly implicated in negative affect. Specifically, after a 5-day SF procedure that selectively fragmented REM sleep, cholinergic output neurons (ChNs) in the mHb exhibited increased spontaneous firing rate and enhanced firing regularity in brain slices. The SF-induced firing changes remained intact upon inhibition of glutamate, GABA, acetylcholine, and histamine receptors, suggesting cell-autonomous mechanisms independent of synaptic transmissions. Moreover, the SF-induced hyperactivity was not because of enhanced intrinsic membrane excitability, but was accompanied by depolarized resting membrane potential in mHb ChNs. Furthermore, inhibition of TASK-3 (KCNK9) channels, a subtype of two-pore domain K+ channels, mimicked the SF effects by increasing the firing rate and regularity, as well as depolarizing the resting membrane potential in mHb ChNs in control-sleep mice. These effects of TASK-3 inhibition were absent in SF mice, suggesting reduced TASK-3 activity following SF. By contrast, inhibition of small-conductance Ca2+-activated K+ (SK) channels did not produce similar effects. Thus, SF compromised TASK-3 function in mHb ChNs, which likely led to depolarized resting membrane potential and increased spontaneous firing. These results not only demonstrate that selective REM sleep disturbance leads to hyperactivity of mHb ChNs, but also identify a key molecular substrate through which REM sleep disturbance may alter affect regulation.
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Beckner ME. A roadmap for potassium buffering/dispersion via the glial network of the CNS. Neurochem Int 2020; 136:104727. [PMID: 32194142 DOI: 10.1016/j.neuint.2020.104727] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 03/08/2020] [Accepted: 03/09/2020] [Indexed: 12/19/2022]
Abstract
Glia use multiple mechanisms to mediate potassium fluxes that support neuronal function. In addition to changes in potassium levels within synapses, these ions are dynamically dispersed through the interstitial parenchyma, perivascular spaces, leptomeninges, cerebrospinal fluid, choroid plexus, blood, vitreous, and endolymph. Neural circuits drive diversity in the glia that buffer potassium and this is reciprocal. Glia mediate buffering of potassium locally at glial-neuronal interfaces and via widespread networked connections. Control of potassium levels in the central nervous system is mediated by mechanisms operating at various loci with complexity that is difficult to model. However, major components of networked glial buffering are known. The role that potassium buffering plays in homeostasis of the CNS underlies some pathologic phenomena. An overview of potassium fluxes in the CNS is relevant for understanding consequences of pathogenic sequence variants in genes that encode potassium buffering proteins. Potassium flows in the CNS are described as follows: K1, the coordinated potassium fluxes within the astrocytic cradle around the synapse; K2, temporary storage of potassium within astrocytic processes in proposed microdomains; K3, potassium fluxes between oligodendrocytes and astrocytes; K4, potassium fluxes between astrocytes; K5, astrocytic potassium flux mediation of neurovasular coupling; K6, CSF delivery of potassium to perivascular spaces with dispersion to interstitial fluid between astrocytic endfeet; K7, astrocytic delivery of potassium to CSF and K8, choroid plexus (modified glia) regulation of potassium at the blood-CSF barrier. Components, mainly potassium channels, transporters, connexins and modulators, and the pathogenic sequence variants of their genes with the associated diseases are described.
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Affiliation(s)
- Marie E Beckner
- School of Biomedical Sciences, Kent State University, Kent, OH, USA.
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