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Chuinsiri N, Siraboriphantakul N, Kendall L, Yarova P, Nile CJ, Song B, Obara I, Durham J, Telezhkin V. Calcium-sensing receptor regulates Kv7 channels via G i/o protein signalling and modulates excitability of human induced pluripotent stem cell-derived nociceptive-like neurons. Br J Pharmacol 2024; 181:2676-2696. [PMID: 38627101 DOI: 10.1111/bph.16349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 01/29/2024] [Accepted: 02/15/2024] [Indexed: 07/03/2024] Open
Abstract
BACKGROUND AND PURPOSE Neuropathic pain, a debilitating condition with unmet medical needs, can be characterised as hyperexcitability of nociceptive neurons caused by dysfunction of ion channels. Voltage-gated potassium channels type 7 (Kv7), responsible for maintaining neuronal resting membrane potential and thus excitability, reside under tight control of G protein-coupled receptors (GPCRs). Calcium-sensing receptor (CaSR) is a GPCR that regulates the activity of numerous ion channels, but whether CaSR can control Kv7 channel function has been unexplored until now. EXPERIMENTAL APPROACH Experiments were conducted in recombinant cell models, mouse dorsal root ganglia (DRG) neurons and human induced pluripotent stem cell (hiPSC)-derived nociceptive-like neurons using patch-clamp electrophysiology and molecular biology techniques. KEY RESULTS Our results demonstrate that CaSR is expressed in recombinant cell models, hiPSC-derived nociceptive-like neurons and mouse DRG neurons, and its activation induced depolarisation via Kv7.2/7.3 channel inhibition. The CaSR-Kv7.2/7.3 channel crosslink was mediated via the Gi/o protein-adenylate cyclase-cyclicAMP-protein kinase A signalling cascade. Suppression of CaSR function demonstrated a potential to rescue hiPSC-derived nociceptive-like neurons from algogenic cocktail-induced hyperexcitability. CONCLUSION AND IMPLICATIONS This study demonstrates that the CaSR-Kv7.2/7.3 channel crosslink, via a Gi/o protein signalling pathway, effectively regulates neuronal excitability, providing a feasible pharmacological target for neuronal hyperexcitability management in neuropathic pain.
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Affiliation(s)
- Nontawat Chuinsiri
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Institute of Dentistry, Suranaree University of Technology, Nakhon Ratchasima, Thailand
- Oral Health Center, Suranaree University of TechnologyHospital, Suranaree University of Technology, Nakhon Ratchasima, Thailand
| | | | - Luke Kendall
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Polina Yarova
- Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Christopher J Nile
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Bing Song
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, UK
| | - Ilona Obara
- School of Pharmacy, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Justin Durham
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Vsevolod Telezhkin
- School of Dental Sciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- Institute of Biomedical and Health Engineering, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
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Aceto G, Nardella L, Nanni S, Pecci V, Bertozzi A, Nutarelli S, Viscomi MT, Colussi C, D'Ascenzo M, Grassi C. Glycine-induced activation of GPR158 increases the intrinsic excitability of medium spiny neurons in the nucleus accumbens. Cell Mol Life Sci 2024; 81:268. [PMID: 38884814 DOI: 10.1007/s00018-024-05260-w] [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: 02/02/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 06/18/2024]
Abstract
It has been recently established that GPR158, a class C orphan G protein-coupled receptor, serves as a metabotropic glycine receptor. GPR158 is highly expressed in the nucleus accumbens (NAc), a major input structure of the basal ganglia that integrates information from cortical and subcortical structures to mediate goal-directed behaviors. However, whether glycine modulates neuronal activity in the NAc through GPR158 activation has not been investigated yet. Using whole-cell patch-clamp recordings, we found that glycine-dependent activation of GPR158 increased the firing rate of NAc medium spiny neurons (MSNs) while it failed to significantly affect the excitability of cholinergic interneurons (CIN). In MSNs GPR158 activation reduced the latency to fire, increased the action potential half-width, and reduced action potential afterhyperpolarization, effects that are all consistent with negative modulation of potassium M-currents, that in the central nervous system are mainly carried out by Kv7/KCNQ-channels. Indeed, we found that the GPR158-induced increase in MSN excitability was associated with decreased M-current amplitude, and selective pharmacological inhibition of the M-current mimicked and occluded the effects of GPR158 activation. In addition, when the protein kinase A (PKA) or extracellular signal-regulated kinase (ERK) signaling was pharmacologically blocked, modulation of MSN excitability by GPR158 activation was suppressed. Moreover, GPR158 activation increased the phosphorylation of ERK and Kv7.2 serine residues. Collectively, our findings suggest that GPR158/PKA/ERK signaling controls MSN excitability via Kv7.2 modulation. Glycine-dependent activation of GPR158 may significantly affect MSN firing in vivo, thus potentially mediating specific aspects of goal-induced behaviors.
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Affiliation(s)
- Giuseppe Aceto
- Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, 00168, Italy
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
| | - Luca Nardella
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
| | - Simona Nanni
- Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, 00168, Italy
- Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
| | - Valeria Pecci
- Department of Translational Medicine and Surgery, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
| | - Alessia Bertozzi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
- Istituto di Analisi dei Sistemi ed Informatica "Antonio Ruberti", National Research Council, Rome, Italy
| | - Sofia Nutarelli
- Department of Life Science and Public Health, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
| | - Maria Teresa Viscomi
- Department of Life Science and Public Health, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
| | - Claudia Colussi
- Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, 00168, Italy
- Istituto di Analisi dei Sistemi ed Informatica "Antonio Ruberti", National Research Council, Rome, Italy
| | - Marcello D'Ascenzo
- Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, 00168, Italy.
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, 00168, Italy.
| | - Claudio Grassi
- Fondazione Policlinico Universitario Agostino Gemelli, IRCCS, Rome, 00168, Italy
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, 00168, Italy
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3
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Qiu J, Voliotis M, Bosch MA, Li XF, Zweifel LS, Tsaneva-Atanasova K, O’Byrne KT, Rønnekleiv OK, Kelly MJ. Estradiol elicits distinct firing patterns in arcuate nucleus kisspeptin neurons of females through altering ion channel conductances. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.20.581121. [PMID: 38915596 PMCID: PMC11195100 DOI: 10.1101/2024.02.20.581121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Hypothalamic kisspeptin (Kiss1) neurons are vital for pubertal development and reproduction. Arcuate nucleus Kiss1 (Kiss1ARH) neurons are responsible for the pulsatile release of Gonadotropin-releasing Hormone (GnRH). In females, the behavior of Kiss1ARH neurons, expressing Kiss1, Neurokinin B (NKB), and Dynorphin (Dyn), varies throughout the ovarian cycle. Studies indicate that 17β-estradiol (E2) reduces peptide expression but increases Vglut2 mRNA and glutamate neurotransmission in these neurons, suggesting a shift from peptidergic to glutamatergic signaling. To investigate this shift, we combined transcriptomics, electrophysiology, and mathematical modeling. Our results demonstrate that E2 treatment upregulates the mRNA expression of voltage-activated calcium channels, elevating the whole-cell calcium current and that contribute to high-frequency burst firing. Additionally, E2 treatment decreased the mRNA levels of Canonical Transient Receptor Potential (TPRC) 5 and G protein-coupled K+ (GIRK) channels. When TRPC5 channels in Kiss1ARH neurons were deleted using CRISPR, the slow excitatory postsynaptic potential (sEPSP) was eliminated. Our data enabled us to formulate a biophysically realistic mathematical model of the Kiss1ARH neuron, suggesting that E2 modifies ionic conductances in Kiss1ARH neurons, enabling the transition from high frequency synchronous firing through NKB-driven activation of TRPC5 channels to a short bursting mode facilitating glutamate release. In a low E2 milieu, synchronous firing of Kiss1ARH neurons drives pulsatile release of GnRH, while the transition to burst firing with high, preovulatory levels of E2 would facilitate the GnRH surge through its glutamatergic synaptic connection to preoptic Kiss1 neurons.
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Affiliation(s)
- Jian Qiu
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Margaritis Voliotis
- Department of Mathematics and Statistics, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
- Living Systems Institute, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
| | - Martha A. Bosch
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
| | - Xiao Feng Li
- Department of Women and Children’s Health, School of Life Course and Population Sciences, King’s College London, Guy’s Campus, London SE1 1UL, UK
| | - Larry S. Zweifel
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
- Depatment of Pharmacology, University of Washington, Seattle, WA 98195, USA
| | - Krasimira Tsaneva-Atanasova
- Department of Mathematics and Statistics, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
- Living Systems Institute, University of Exeter, Stocker Rd, Exeter, EX4 4PY, UK
| | - Kevin T. O’Byrne
- Department of Women and Children’s Health, School of Life Course and Population Sciences, King’s College London, Guy’s Campus, London SE1 1UL, UK
| | - Oline K. Rønnekleiv
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, USA
| | - Martin J. Kelly
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR 97239, USA
- Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR 97006, USA
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Mehrdel B, Villalba-Galea CA. Effect of a sensing charge mutation on the deactivation of KV7.2 channels. J Gen Physiol 2024; 156:e202213284. [PMID: 38236165 PMCID: PMC10796215 DOI: 10.1085/jgp.202213284] [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] [Received: 10/19/2022] [Revised: 08/28/2023] [Accepted: 01/03/2024] [Indexed: 01/19/2024] Open
Abstract
Potassium-selective, voltage-gated channels of the KV7 family are critical regulators of electrical excitability in many cell types. Removing the outermost putative sensing charge (R198) of the human KV7.2 shifts its activation voltage dependence toward more negative potentials. This suggests that removing a charge "at the top" of the fourth (S4) segment of the voltage-sensing domain facilitates activation. Here, we hypothesized that restoring that charge would bring back the activation to its normal voltage range. We introduced the mutation R198H in KV7.2 with the idea that titrating the introduced histidine with protons would reinstate the sensing charge. As predicted, the mutant's activation voltage dependence changed as a function of the external pH (pHEXT) while modest changes in the activation voltage dependence were observed with the wild-type (WT) channel. On the other hand, the deactivation kinetics of the R198H mutant was remarkably sensitive to pHEXT changes, readily deactivating at pHEXT 6, while becoming slower to deactivate at pHEXT 8. In contrast, the KV7.2 WT displayed modest changes in the deactivation kinetics as a function of pHEXT. This suggested that the charge of residue 198 was critical for deactivation. However, in a surprising turn, the mutant R198Q-a non-titratable mutation-also displayed a high pHEXT sensitivity activity. We thus concluded that rather than the charge at position 198, the protonation status of the channel's extracellular face modulates the open channel stabilization and that the charge of residue 198 is required for the voltage sensor to effectively deactivate the channel, overcoming the stabilizing effect of high pHEXT.
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Affiliation(s)
- Baharak Mehrdel
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, USA
| | - Carlos A. Villalba-Galea
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, USA
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Jiang S, Liu B, Lin K, Li L, Li R, Tan S, Zhang X, Jiang L, Ni H, Wang Y, Ding H, Hu J, Qian H, Ge R. Impacted spike frequency adaptation associated with reduction of KCNQ2/3 exacerbates seizure activity in temporal lobe epilepsy. Hippocampus 2024; 34:58-72. [PMID: 38049972 DOI: 10.1002/hipo.23587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 09/21/2023] [Accepted: 10/28/2023] [Indexed: 12/06/2023]
Abstract
Numerous epilepsy-related genes have been identified in recent decades by unbiased genome-wide screens. However, the available druggable targets for temporal lobe epilepsy (TLE) remain limited. Furthermore, a substantial pool of candidate genes potentially applicable to TLE therapy awaits further validation. In this study, we reveal the significant role of KCNQ2 and KCNQ3, two M-type potassium channel genes, in the onset of seizures in TLE. Our investigation began with a quantitative analysis of two publicly available TLE patient databases to establish a correlation between seizure onset and the downregulated expression of KCNQ2/3. We then replicated these pathological changes in a pilocarpine seizure mouse model and observed a decrease in spike frequency adaptation due to the affected M-currents in dentate gyrus granule neurons. In addition, we performed a small-scale simulation of the dentate gyrus network and confirmed that the impaired spike frequency adaptation of granule cells facilitated epileptiform activity throughout the network. This, in turn, resulted in prolonged seizure duration and reduced interictal intervals. Our findings shed light on an underlying mechanism contributing to ictogenesis in the TLE hippocampus and suggest a promising target for the development of antiepileptic drugs.
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Affiliation(s)
- Shicheng Jiang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Bei Liu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Kaiwen Lin
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Lianjun Li
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Rongrong Li
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Shuo Tan
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Xinyu Zhang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Lei Jiang
- Department of General Surgery, The Second Affiliated Hospital of Bengbu Medical College, Bengbu, Anhui, China
| | - Hong Ni
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Yuanyuan Wang
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
| | - Haihu Ding
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Bengbu Medical College, Bengbu, Anhui, China
| | - Jing Hu
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Hao Qian
- Sichuan Provincial Key Laboratory for Human Disease Gene Study, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
| | - Rongjing Ge
- Department of Pathophysiology, Bengbu Medical College, Bengbu, Anhui, China
- Laboratory of Brain and Psychiatric Disease, Bengbu Medical College, Bengbu, Anhui, China
- Key Laboratory of Cardiovascular and Cerebrovascular Diseases, Bengbu Medical College, Bengbu, Anhui, China
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6
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Ye J, Tang S, Miao P, Gong Z, Shu Q, Feng J, Li Y. Clinical analysis and functional characterization of KCNQ2-related developmental and epileptic encephalopathy. Front Mol Neurosci 2023; 16:1205265. [PMID: 37497102 PMCID: PMC10366601 DOI: 10.3389/fnmol.2023.1205265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 06/19/2023] [Indexed: 07/28/2023] Open
Abstract
Background Developmental and epileptic encephalopathy (DEE) is a condition characterized by severe seizures and a range of developmental impairments. Pathogenic variants in KCNQ2, encoding for potassium channel subunit, cause KCNQ2-related DEE. This study aimed to examine the relationships between genotype and phenotype in KCNQ2-related DEE. Methods In total, 12 patients were enrolled in this study for genetic testing, clinical analysis, and developmental evaluation. Pathogenic variants of KCNQ2 were characterized through a whole-cell electrophysiological recording expressed in Chinese hamster ovary (CHO) cells. The expression levels of the KCNQ2 subunit and its localization at the plasma membrane were determined using Western blot analysis. Results Seizures were detected in all patients. All DEE patients showed evidence of developmental delay. In total, 11 de novo KCNQ2 variants were identified, including 10 missense variants from DEE patients and one truncating variant from a patient with self-limited neonatal epilepsy (SeLNE). All variants were found to be loss of function through analysis of M-currents using patch-clamp recordings. The functional impact of variants on M-current in heteromericKCNQ2/3 channels may be associated with the severity of developmental disorders in DEE. The variants with dominant-negative effects in heteromeric channels may be responsible for the profound developmental phenotype. Conclusion The mechanism underlying KCNQ2-related DEE involves a reduction of the M-current through dominant-negative effects, and the severity of developmental disorders in DEE may be predicted by the impact of variants on the M-current of heteromericKCNQ2/3 channels.
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Affiliation(s)
- Jia Ye
- National Clinical Research Center for Child Health, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Siyang Tang
- Pediatric Department, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Pu Miao
- Pediatric Department, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhefeng Gong
- School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Qiang Shu
- Pediatric Department, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhua Feng
- School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuezhou Li
- National Clinical Research Center for Child Health, The Children's Hospital, Zhejiang University School of Medicine, Hangzhou, China
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Kapell H, Fazio L, Dyckow J, Schwarz S, Cruz-Herranz A, Mayer C, Campos J, D’Este E, Möbius W, Cordano C, Pröbstel AK, Gharagozloo M, Zulji A, Narayanan Naik V, Delank A, Cerina M, Müntefering T, Lerma-Martin C, Sonner JK, Sin JH, Disse P, Rychlik N, Sabeur K, Chavali M, Srivastava R, Heidenreich M, Fitzgerald KC, Seebohm G, Stadelmann C, Hemmer B, Platten M, Jentsch TJ, Engelhardt M, Budde T, Nave KA, Calabresi PA, Friese MA, Green AJ, Acuna C, Rowitch DH, Meuth SG, Schirmer L. Neuron-oligodendrocyte potassium shuttling at nodes of Ranvier protects against inflammatory demyelination. J Clin Invest 2023; 133:e164223. [PMID: 36719741 PMCID: PMC10065072 DOI: 10.1172/jci164223] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 01/27/2023] [Indexed: 02/01/2023] Open
Abstract
Multiple sclerosis (MS) is a progressive inflammatory demyelinating disease of the CNS. Increasing evidence suggests that vulnerable neurons in MS exhibit fatal metabolic exhaustion over time, a phenomenon hypothesized to be caused by chronic hyperexcitability. Axonal Kv7 (outward-rectifying) and oligodendroglial Kir4.1 (inward-rectifying) potassium channels have important roles in regulating neuronal excitability at and around the nodes of Ranvier. Here, we studied the spatial and functional relationship between neuronal Kv7 and oligodendroglial Kir4.1 channels and assessed the transcriptional and functional signatures of cortical and retinal projection neurons under physiological and inflammatory demyelinating conditions. We found that both channels became dysregulated in MS and experimental autoimmune encephalomyelitis (EAE), with Kir4.1 channels being chronically downregulated and Kv7 channel subunits being transiently upregulated during inflammatory demyelination. Further, we observed that pharmacological Kv7 channel opening with retigabine reduced neuronal hyperexcitability in human and EAE neurons, improved clinical EAE signs, and rescued neuronal pathology in oligodendrocyte-Kir4.1-deficient (OL-Kir4.1-deficient) mice. In summary, our findings indicate that neuron-OL compensatory interactions promoted resilience through Kv7 and Kir4.1 channels and identify pharmacological activation of nodal Kv7 channels as a neuroprotective strategy against inflammatory demyelination.
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Affiliation(s)
- Hannah Kapell
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Luca Fazio
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
- Department of Neurology, University of Düsseldorf, Dusseldorf, Germany
| | - Julia Dyckow
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Sophia Schwarz
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Andrés Cruz-Herranz
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
| | - Christina Mayer
- Institute of Neuroimmunology and Multiple Sclerosis, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Joaquin Campos
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Elisa D’Este
- Optical Microscopy Facility, Max Planck Institute for Medical Research, Heidelberg, Germany
| | - Wiebke Möbius
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Cluster of Excellence, “Multiscale Bioimaging: from Molecular Machines to Network of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Christian Cordano
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
| | - Anne-Katrin Pröbstel
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
- Neurologic Clinic and Policlinic and Research Center for Clinical Neuroimmunology and Neuroscience Basel, Departments of Medicine, Biomedicine, and Clinical Research, University Hospital of Basel, University of Basel, Basel, Switzerland
| | - Marjan Gharagozloo
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Amel Zulji
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Venu Narayanan Naik
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
| | - Anna Delank
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
| | - Manuela Cerina
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
| | | | - Celia Lerma-Martin
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Jana K. Sonner
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - Jung Hyung Sin
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
| | - Paul Disse
- Institute for Genetics of Heart Diseases (IfGH), Cellular Electrophysiology and Molecular Biology, UKM, Münster, Germany
- University of Münster, Chembion, Münster, Germany
| | - Nicole Rychlik
- University of Münster, Chembion, Münster, Germany
- Institute of Physiology I, University of Münster, Münster, Germany
| | - Khalida Sabeur
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and
- Department of Pediatrics, UCSF, San Francisco, California, USA
| | - Manideep Chavali
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and
- Department of Pediatrics, UCSF, San Francisco, California, USA
| | - Rajneesh Srivastava
- Department of Neurology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Matthias Heidenreich
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Kathryn C. Fitzgerald
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guiscard Seebohm
- Institute for Genetics of Heart Diseases (IfGH), Cellular Electrophysiology and Molecular Biology, UKM, Münster, Germany
| | - Christine Stadelmann
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Institute of Neuropathology, University Medical Center, Göttingen, Germany
| | - Bernhard Hemmer
- Department of Neurology, School of Medicine, Technical University of Munich, Munich, Germany
- Munich Cluster for Systems Neurology, Munich, Germany
| | - Michael Platten
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- DKTK Clinical Cooperation Unit Neuroimmunology and Brain Tumor Immunology, German Cancer Research Center (DKFZ), INF 280, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences (IZN) and
- Mannheim Center for Translational Neuroscience and Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Thomas J. Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
- Neurocure Cluster of Excellence, Charité University Medicine Berlin, Berlin, Germany
| | - Maren Engelhardt
- Mannheim Center for Translational Neuroscience and Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Institute of Neuroanatomy, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Institute of Anatomy and Cell Biology, Johannes Kepler University Linz, Linz, Austria
| | - Thomas Budde
- Institute of Physiology I, University of Münster, Münster, Germany
| | - Klaus-Armin Nave
- Electron Microscopy Core Unit, Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Peter A. Calabresi
- Departments of Neurology and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Manuel A. Friese
- Institute of Neuroimmunology and Multiple Sclerosis, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Ari J. Green
- Weill Institute for Neurosciences, Department of Neurology, UCSF, San Francisco, California, USA
- Department of Ophthalmology, UCSF, San Francisco, California, USA
| | - Claudio Acuna
- Chica and Heinz Schaller Research Group, Institute of Anatomy and Cell Biology, Heidelberg University, Heidelberg, Germany
| | - David H. Rowitch
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research and
- Department of Pediatrics, UCSF, San Francisco, California, USA
- Wellcome Trust–Medical Research Council Stem Cell Institute and
- Department of Paediatrics, University of Cambridge, Cambridge, United Kingdom
- Department of Neurosurgery, UCSF, San Francisco, California, USA
| | - Sven G. Meuth
- Department of Neurology with Institute of Translational Neurology, University Hospital Münster (UKM), Münster, Germany
- Department of Neurology, University of Düsseldorf, Dusseldorf, Germany
| | - Lucas Schirmer
- Department of Neurology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
- Interdisciplinary Center for Neurosciences (IZN) and
- Mannheim Center for Translational Neuroscience and Institute for Innate Immunoscience, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
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8
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Brun L, Viemari J, Villard L. Mouse models of Kcnq2 dysfunction. Epilepsia 2022; 63:2813-2826. [PMID: 36047730 PMCID: PMC9828481 DOI: 10.1111/epi.17405] [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: 06/17/2022] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 01/12/2023]
Abstract
Variants in the Kv7.2 channel subunit encoded by the KCNQ2 gene cause epileptic disorders ranging from a benign form with self-limited epileptic seizures and normal development to severe forms with intractable epileptic seizures and encephalopathy. The biological mechanisms involved in these neurological diseases are still unclear. The disease remains intractable in patients affected by the severe form. Over the past 20 years, KCNQ2 models have been developed to elucidate pathological mechanisms and to identify new therapeutic targets. The diversity of Kcnq2 mouse models has proven invaluable to access neuronal networks and evaluate the associated cognitive deficits. This review summarizes the available models and their contribution to our current understanding of KCNQ2 epileptic disorders.
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Affiliation(s)
- Lucile Brun
- Aix Marseille Univ, Inserm, MMGMarseilleFrance
| | | | - Laurent Villard
- Aix Marseille Univ, Inserm, MMGMarseilleFrance,Service de Génétique Médicale, AP‐HM, Hôpital de La TimoneMarseilleFrance
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9
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Bar L, Shalom L, Lezmy J, Peretz A, Attali B. Excitatory and inhibitory hippocampal neurons differ in their homeostatic adaptation to chronic M-channel modulation. Front Mol Neurosci 2022; 15:972023. [PMID: 36311018 PMCID: PMC9614320 DOI: 10.3389/fnmol.2022.972023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/27/2022] [Indexed: 12/03/2022] Open
Abstract
A large body of studies has investigated bidirectional homeostatic plasticity both in vitro and in vivo using numerous pharmacological manipulations of activity or behavioral paradigms. However, these experiments rarely explored in the same cellular system the bidirectionality of the plasticity and simultaneously on excitatory and inhibitory neurons. M-channels are voltage-gated potassium channels that play a crucial role in regulating neuronal excitability and plasticity. In cultured hippocampal excitatory neurons, we previously showed that chronic exposure to the M-channel blocker XE991 leads to adaptative compensations, thereby triggering at different timescales intrinsic and synaptic homeostatic plasticity. This plastic adaptation barely occurs in hippocampal inhibitory neurons. In this study, we examined whether this homeostatic plasticity induced by M-channel inhibition was bidirectional by investigating the acute and chronic effects of the M-channel opener retigabine on hippocampal neuronal excitability. Acute retigabine exposure decreased excitability in both excitatory and inhibitory neurons. Chronic retigabine treatment triggered in excitatory neurons homeostatic adaptation of the threshold current and spontaneous firing rate at a time scale of 4–24 h. These plastic changes were accompanied by a substantial decrease in the M-current density and by a small, though significant, proximal relocation of Kv7.3-FGF14 segment along the axon initial segment. Thus, bidirectional homeostatic changes were observed in excitatory neurons though not symmetric in kinetics and mechanisms. Contrastingly, in inhibitory neurons, the compensatory changes in intrinsic excitability barely occurred after 48 h, while no homeostatic normalization of the spontaneous firing rate was observed. Our results indicate that excitatory and inhibitory hippocampal neurons differ in their adaptation to chronic alterations in neuronal excitability induced by M-channel bidirectional modulation.
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10
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Tau isoform-specific enhancement of L-type calcium current and augmentation of afterhyperpolarization in rat hippocampal neurons. Sci Rep 2022; 12:15231. [PMID: 36075936 PMCID: PMC9458744 DOI: 10.1038/s41598-022-18648-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 08/17/2022] [Indexed: 11/08/2022] Open
Abstract
Accumulation of tau is observed in dementia, with human tau displaying 6 isoforms grouped by whether they display either 3 or 4 C-terminal repeat domains (3R or 4R) and exhibit no (0N), one (1N) or two (2N) N terminal repeats. Overexpression of 4R0N-tau in rat hippocampal slices enhanced the L-type calcium (Ca2+) current-dependent components of the medium and slow afterhyperpolarizations (AHPs). Overexpression of both 4R0N-tau and 4R2N-tau augmented CaV1.2-mediated L-type currents when expressed in tsA-201 cells, an effect not observed with the third 4R isoform, 4R1N-tau. Current enhancement was only observed when the pore-forming subunit was co-expressed with CaVβ3 and not CaVβ2a subunits. Non-stationary noise analysis indicated that enhanced Ca2+ channel current arose from a larger number of functional channels. 4R0N-tau and CaVβ3 were found to be physically associated by co-immunoprecipitation. In contrast, the 4R1N-tau isoform that did not augment expressed macroscopic L-type Ca2+ current exhibited greatly reduced binding to CaVβ3. These data suggest that physical association between tau and the CaVβ3 subunit stabilises functional L-type channels in the membrane, increasing channel number and Ca2+ influx. Enhancing the Ca2+-dependent component of AHPs would produce cognitive impairment that underlie those seen in the early phases of tauopathies.
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11
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Baculis BC, Kesavan H, Weiss AC, Kim EH, Tracy GC, Ouyang W, Tsai NP, Chung HJ. Homeostatic regulation of extracellular signal-regulated kinase 1/2 activity and axonal K v7.3 expression by prolonged blockade of hippocampal neuronal activity. Front Cell Neurosci 2022; 16:838419. [PMID: 35966206 PMCID: PMC9366003 DOI: 10.3389/fncel.2022.838419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 07/04/2022] [Indexed: 11/17/2022] Open
Abstract
Homeostatic plasticity encompasses the mechanisms by which neurons stabilize their synaptic strength and excitability in response to prolonged and destabilizing changes in their network activity. Prolonged activity blockade leads to homeostatic scaling of action potential (AP) firing rate in hippocampal neurons in part by decreased activity of N-Methyl-D-Aspartate receptors and subsequent transcriptional down-regulation of potassium channel genes including KCNQ3 which encodes Kv7.3. Neuronal Kv7 channels are mostly heterotetramers of Kv7.2 and Kv7.3 subunits and are highly enriched at the axon initial segment (AIS) where their current potently inhibits repetitive and burst firing of APs. However, whether a decrease in Kv7.3 expression occurs at the AIS during homeostatic scaling of intrinsic excitability and what signaling pathway reduces KCNQ3 transcript upon prolonged activity blockade remain unknown. Here, we report that prolonged activity blockade in cultured hippocampal neurons reduces the activity of extracellular signal-regulated kinase 1/2 (ERK1/2) followed by a decrease in the activation of brain-derived neurotrophic factor (BDNF) receptor, Tropomyosin receptor kinase B (TrkB). Furthermore, both prolonged activity blockade and prolonged pharmacological inhibition of ERK1/2 decrease KCNQ3 and BDNF transcripts as well as the density of Kv7.3 and ankyrin-G at the AIS. Collectively, our findings suggest that a reduction in the ERK1/2 activity and subsequent transcriptional down-regulation may serve as a potential signaling pathway that links prolonged activity blockade to homeostatic control of BDNF-TrkB signaling and Kv7.3 density at the AIS during homeostatic scaling of AP firing rate.
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Affiliation(s)
- Brian C. Baculis
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Harish Kesavan
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Amanda C. Weiss
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Edward H. Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Gregory C. Tracy
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Wenhao Ouyang
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Nien-Pei Tsai
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
| | - Hee Jung Chung
- Neuroscience Program, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
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12
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Tracy GC, Wilton AR, Rhodes JS, Chung HJ. Heterozygous Deletion of Epilepsy Gene KCNQ2 Has Negligible Effects on Learning and Memory. Front Behav Neurosci 2022; 16:930216. [PMID: 35928789 PMCID: PMC9344800 DOI: 10.3389/fnbeh.2022.930216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/10/2022] [Indexed: 11/13/2022] Open
Abstract
Neuronal Kv7/Potassium Voltage-Gated Channel Subfamily Q (KCNQ) potassium channels underlie M-current that potently suppresses repetitive and burst firing of action potentials (APs). They are mostly heterotetramers of Kv7.2 and Kv7.3 subunits in the hippocampus and cortex, the brain regions important for cognition and behavior. Underscoring their critical roles in inhibiting neuronal excitability, autosomal dominantly inherited mutations in Potassium Voltage-Gated Channel Subfamily Q Member 2 (KCNQ2) and Potassium Voltage-Gated Channel Subfamily Q Member 3 (KCNQ3) genes are associated with benign familial neonatal epilepsy (BFNE) in which most seizures spontaneously remit within months without cognitive deficits. De novo mutations in KCNQ2 also cause epileptic encephalopathy (EE), which is characterized by persistent seizures that are often drug refractory, neurodevelopmental delay, and intellectual disability. Heterozygous expression of EE variants of KCNQ2 is recently shown to induce spontaneous seizures and cognitive deficit in mice, although it is unclear whether this cognitive deficit is caused directly by Kv7 disruption or by persistent seizures in the developing brain as a consequence of Kv7 disruption. In this study, we examined the role of Kv7 channels in learning and memory by behavioral phenotyping of the KCNQ2+/- mice, which lack a single copy of KCNQ2 but dos not display spontaneous seizures. We found that both KCNQ2+/- and wild-type (WT) mice showed comparable nociception in the tail-flick assay and fear-induced learning and memory during a passive inhibitory avoidance (IA) test and contextual fear conditioning (CFC). Both genotypes displayed similar object location and recognition memory. These findings together provide evidence that heterozygous loss of KCNQ2 has minimal effects on learning or memory in mice in the absence of spontaneous seizures.
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Affiliation(s)
- Gregory C. Tracy
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Angelina R. Wilton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Justin S. Rhodes
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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13
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Dai G. Neuronal KCNQ2/3 channels are recruited to lipid raft microdomains by palmitoylation of BACE1. J Gen Physiol 2022; 154:213033. [PMID: 35201266 PMCID: PMC8876601 DOI: 10.1085/jgp.202112888] [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] [Received: 02/02/2021] [Accepted: 02/04/2022] [Indexed: 12/14/2022] Open
Abstract
β-Secretase 1 (β-site amyloid precursor protein [APP]-cleaving enzyme 1, BACE1) plays a crucial role in the amyloidogenesis of Alzheimer’s disease (AD). BACE1 was also discovered to act like an auxiliary subunit to modulate neuronal KCNQ2/3 channels independently of its proteolytic function. BACE1 is palmitoylated at its carboxyl-terminal region, which brings BACE1 to ordered, cholesterol-rich membrane microdomains (lipid rafts). However, the physiological consequences of this specific localization of BACE1 remain elusive. Using spectral Förster resonance energy transfer (FRET), BACE1 and KCNQ2/3 channels were confirmed to form a signaling complex, a phenomenon that was relatively independent of the palmitoylation of BACE1. Nevertheless, palmitoylation of BACE1 was required for recruitment of KCNQ2/3 channels to lipid-raft domains. Two fluorescent probes, designated L10 and S15, were used to label lipid-raft and non-raft domains of the plasma membrane, respectively. Coexpressing BACE1 substantially elevated FRET between L10 and KCNQ2/3, whereas the BACE1-4C/A quadruple mutation failed to produce this effect. In contrast, BACE1 had no significant effect on FRET between S15 probes and KCNQ2/3 channels. A reduction of BACE1-dependent FRET between raft-targeting L10 probes and KCNQ2/3 channels by applying the cholesterol-extracting reagent methyl-β-cyclodextrin (MβCD), raft-disrupting general anesthetics, or pharmacological inhibitors of palmitoylation, all supported the hypothesis of the palmitoylation-dependent and raft-specific localization of KCNQ2/3 channels. Furthermore, mutating the four carboxyl-terminal cysteines (4C/A) of BACE1 abolished the BACE1-dependent increase of FRET between KCNQ2/3 and the lipid raft–specific protein caveolin 1. Taking these data collectively, we propose that the AD-related protein BACE1 underlies the localization of a neuronal potassium channel.
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Affiliation(s)
- Gucan Dai
- Department of Physiology and Biophysics, University of Washington, Seattle, WA
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14
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Bottom-Tanzer S, Dulla C. Keeping up with KCNQ2: A New Model of Epileptic Encephalopathy. Epilepsy Curr 2022; 22:141-143. [PMID: 35444503 PMCID: PMC8988726 DOI: 10.1177/15357597221082485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
| | - Chris Dulla
- Tufts University School of Medicine, Boston, MA, USA
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15
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Sahu G, Turner RW. The Molecular Basis for the Calcium-Dependent Slow Afterhyperpolarization in CA1 Hippocampal Pyramidal Neurons. Front Physiol 2022; 12:759707. [PMID: 35002757 PMCID: PMC8730529 DOI: 10.3389/fphys.2021.759707] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 11/01/2021] [Indexed: 12/02/2022] Open
Abstract
Neuronal signal transmission depends on the frequency, pattern, and timing of spike output, each of which are shaped by spike afterhyperpolarizations (AHPs). There are classically three post-spike AHPs of increasing duration categorized as fast, medium and slow AHPs that hyperpolarize a cell over a range of 10 ms to 30 s. Intensive early work on CA1 hippocampal pyramidal cells revealed that all three AHPs incorporate activation of calcium-gated potassium channels. The ionic basis for a fAHP was rapidly attributed to the actions of big conductance (BK) and the mAHP to small conductance (SK) or Kv7 potassium channels. In stark contrast, the ionic basis for a prominent slow AHP of up to 30 s duration remained an enigma for over 30 years. Recent advances in pharmacological, molecular, and imaging tools have uncovered the expression of a calcium-gated intermediate conductance potassium channel (IK, KCa3.1) in central neurons that proves to contribute to the slow AHP in CA1 hippocampal pyramidal cells. Together the data show that the sAHP arises in part from a core tripartite complex between Cav1.3 (L-type) calcium channels, ryanodine receptors, and IK channels at endoplasmic reticulum-plasma membrane junctions. Work on the sAHP in CA1 pyramidal neurons has again quickened pace, with identified contributions by both IK channels and the Na-K pump providing answers to several mysteries in the pharmacological properties of the sAHP.
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Affiliation(s)
- Giriraj Sahu
- National Institute of Pharmaceutical Education and Research Ahmedabad, Ahmedabad, India
| | - Ray W Turner
- Department Cell Biology & Anatomy, Cumming School of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
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16
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Kim EC, Zhang J, Tang AY, Bolton EC, Rhodes JS, Christian-Hinman CA, Chung HJ. Spontaneous seizure and memory loss in mice expressing an epileptic encephalopathy variant in the calmodulin-binding domain of K v7.2. Proc Natl Acad Sci U S A 2021; 118:e2021265118. [PMID: 34911751 PMCID: PMC8713762 DOI: 10.1073/pnas.2021265118] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/07/2021] [Indexed: 11/18/2022] Open
Abstract
Epileptic encephalopathy (EE) is characterized by seizures that respond poorly to antiseizure drugs, psychomotor delay, and cognitive and behavioral impairments. One of the frequently mutated genes in EE is KCNQ2, which encodes the Kv7.2 subunit of voltage-gated Kv7 potassium channels. Kv7 channels composed of Kv7.2 and Kv7.3 are enriched at the axonal surface, where they potently suppress neuronal excitability. Previously, we reported that the de novo dominant EE mutation M546V in human Kv7.2 blocks calmodulin binding to Kv7.2 and axonal surface expression of Kv7 channels via their intracellular retention. However, whether these pathogenic mechanisms underlie epileptic seizures and behavioral comorbidities remains unknown. Here, we report conditional transgenic cKcnq2+/M547V mice, in which expression of mouse Kv7.2-M547V (equivalent to human Kv7.2-M546V) is induced in forebrain excitatory pyramidal neurons and astrocytes. These mice display early mortality, spontaneous seizures, enhanced seizure susceptibility, memory impairment, and repetitive behaviors. Furthermore, hippocampal pathology shows widespread neurodegeneration and reactive astrocytes. This study demonstrates that the impairment in axonal surface expression of Kv7 channels is associated with epileptic seizures, cognitive and behavioral deficits, and neuronal loss in KCNQ2-related EE.
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Affiliation(s)
- Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Andy Y Tang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Eric C Bolton
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Justin S Rhodes
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Catherine A Christian-Hinman
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801;
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801
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17
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Posttranscriptional modulation of KCNQ2 gene expression by the miR-106b microRNA family. Proc Natl Acad Sci U S A 2021; 118:2110200118. [PMID: 34785595 DOI: 10.1073/pnas.2110200118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2021] [Indexed: 12/15/2022] Open
Abstract
MicroRNAs (miRNAs) have recently emerged as important regulators of ion channel expression. We show here that select miR-106b family members repress the expression of the KCNQ2 K+ channel protein by binding to the 3'-untranslated region of KCNQ2 messenger RNA. During the first few weeks after birth, the expression of miR-106b family members rapidly decreases, whereas KCNQ2 protein level inversely increases. Overexpression of miR-106b mimics resulted in a reduction in KCNQ2 protein levels. Conversely, KCNQ2 levels were up-regulated in neurons transfected with antisense miRNA inhibitors. By constructing more specific and stable forms of miR-106b controlling systems, we further confirmed that overexpression of precursor-miR-106b-5p led to a decrease in KCNQ current density and an increase in firing frequency of hippocampal neurons, while tough decoy miR-106b-5p dramatically increased current density and decreased neuronal excitability. These results unmask a regulatory mechanism of KCNQ2 channel expression in early postnatal development and hint at a role for miR-106b up-regulation in the pathophysiology of epilepsy.
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18
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Gao X, Bender F, Soh H, Chen C, Altafi M, Schütze S, Heidenreich M, Gorbati M, Corbu MA, Carus-Cadavieco M, Korotkova T, Tzingounis AV, Jentsch TJ, Ponomarenko A. Place fields of single spikes in hippocampus involve Kcnq3 channel-dependent entrainment of complex spike bursts. Nat Commun 2021; 12:4801. [PMID: 34376649 PMCID: PMC8355348 DOI: 10.1038/s41467-021-24805-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 06/29/2021] [Indexed: 02/07/2023] Open
Abstract
Hippocampal pyramidal cells encode an animal's location by single action potentials and complex spike bursts. These elementary signals are believed to play distinct roles in memory consolidation. The timing of single spikes and bursts is determined by intrinsic excitability and theta oscillations (5-10 Hz). Yet contributions of these dynamics to place fields remain elusive due to the lack of methods for specific modification of burst discharge. In mice lacking Kcnq3-containing M-type K+ channels, we find that pyramidal cell bursts are less coordinated by the theta rhythm than in controls during spatial navigation, but not alert immobility. Less modulated bursts are followed by an intact post-burst pause of single spike firing, resulting in a temporal discoordination of network oscillatory and intrinsic excitability. Place fields of single spikes in one- and two-dimensional environments are smaller in the mutant. Optogenetic manipulations of upstream signals reveal that neither medial septal GABA-ergic nor cholinergic inputs alone, but rather their joint activity, is required for entrainment of bursts. Our results suggest that altered representations by bursts and single spikes may contribute to deficits underlying cognitive disabilities associated with KCNQ3-mutations in humans.
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Affiliation(s)
- Xiaojie Gao
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Franziska Bender
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Heun Soh
- University of Connecticut, Storrs, CT, USA
| | - Changwan Chen
- Max Planck Institute for Metabolism Research, Cologne, Germany
- Institute for Vegetative Physiology, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Mahsa Altafi
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Sebastian Schütze
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Matthias Heidenreich
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
| | - Maria Gorbati
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | | | - Marta Carus-Cadavieco
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Tatiana Korotkova
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
- Max Planck Institute for Metabolism Research, Cologne, Germany
- Institute for Vegetative Physiology, Faculty of Medicine, University of Cologne, Cologne, Germany
| | | | - Thomas J Jentsch
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany.
- Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany.
| | - Alexey Ponomarenko
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
- NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany.
- Institute of Physiology and Pathophysiology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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19
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Stincic TL, Bosch MA, Hunker AC, Juarez B, Connors AM, Zweifel LS, Rønnekleiv OK, Kelly MJ. CRISPR knockdown of Kcnq3 attenuates the M-current and increases excitability of NPY/AgRP neurons to alter energy balance. Mol Metab 2021; 49:101218. [PMID: 33766732 PMCID: PMC8093934 DOI: 10.1016/j.molmet.2021.101218] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 03/12/2021] [Accepted: 03/18/2021] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Arcuate nucleus neuropeptide Y/agouti-related peptide (NPY/AgRP) neurons drive ingestive behavior. The M-current, a subthreshold non-inactivating potassium current, plays a critical role in regulating NPY/AgRP neuronal excitability. Fasting decreases while 17β-estradiol increases the M-current by regulating the mRNA expression of Kcnq2, 3, and 5 (Kv7.2, 3, and 5) channel subunits. Incorporating KCNQ3 into heteromeric channels has been considered essential to generate a robust M-current. Therefore, we investigated the behavioral and physiological effects of selective Kcnq3 deletion from NPY/AgRP neurons. METHODS We used a single adeno-associated viral vector containing a recombinase-dependent Staphylococcus aureus Cas9 with a single-guide RNA to selectively delete Kcnq3 in NPY/AgRP neurons. Single-cell quantitative measurements of mRNA expression and whole-cell patch clamp experiments were conducted to validate the selective knockdown. Body weight, food intake, and locomotor activity were measured in male mice to assess disruptions in energy balance. RESULTS The virus reduced the expression of Kcnq3 mRNA without affecting Kcnq2 or Kcnq5. The M-current was attenuated, causing NPY/AgRP neurons to be more depolarized, exhibit a higher input resistance, and require less depolarizing current to fire action potentials, indicative of increased excitability. Although the resulting decrease in the M-current did not overtly alter ingestive behavior, it significantly reduced the locomotor activity as measured by open-field testing. Control mice on a high-fat diet exhibited an enhanced M-current and increased Kcnq2 and Kcnq3 expression, but the M-current remained significantly attenuated in KCNQ3 knockdown animals. CONCLUSIONS The M-current plays a critical role in modulating the intrinsic excitability of NPY/AgRP neurons that is essential for maintaining energy homeostasis.
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Affiliation(s)
- Todd L Stincic
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA.
| | - Martha A Bosch
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Avery C Hunker
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA
| | - Barbara Juarez
- Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - Ashley M Connors
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Larry S Zweifel
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA, 98195, USA; Department of Pharmacology, University of Washington, Seattle, WA, 98195, USA
| | - Oline K Rønnekleiv
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA
| | - Martin J Kelly
- Department of Chemical Physiology and Biochemistry, Oregon Health and Science University, Portland, OR, 97239, USA; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, 97006, USA.
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20
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Laker D, Tolle F, Stegen M, Heerdegen M, Köhling R, Kirschstein T, Wolfart J. K v7 and K ir6 Channels Shape the Slow AHP in Mouse Dentate Gyrus Granule Cells and Control Burst-like Firing Behavior. Neuroscience 2021; 467:56-72. [PMID: 34048798 DOI: 10.1016/j.neuroscience.2021.05.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 11/29/2022]
Abstract
The slow afterhyperpolarizing potential (sAHP) can silence a neuron for hundreds of milliseconds. Thereby, the sAHP determines the discharge behavior of many types of neurons. In dentate granule cells (DGCs), serving as a filter into the hippocampal network, mostly tonic or adapting discharge properties have been described. As under standard whole-cell recording conditions the sAHP is inhibited, we reevaluated the intrinsic functional phenotype of DGCs and the conductances underlying the sAHP, using gramicidine-perforated patch-clamp technique. We found that in 97/113 (86%) of the DGCs, a burst of action potentials (APs) to excitation ended by a large sAHP, despite continued depolarization. This result suggests that burst-like firing is the default functional phenotype of DGCs and that sAHPs are important for it. Indeed, burst-like firing DGCs showed a significantly higher sAHP-current (IsAHP) amplitude compared to spike-frequency adapting cells (16/113 = 14%). The IsAHP was mediated by Kv7 and Kir6 channels by pharmacological inhibition using XE991 and tolbutamide, although heterogeneously among DGCs. The percent inhibition of IsAHP by these compounds also correlated with the AP number and AP burst length. Application of 100 µM nickel after XE991 and tolbutamide detected a third conductance contributing to burst-like firing and the sAHP, most likely mediated by T-type calcium channels. Lastly, medial perforant path-dentate gyrus long-term potentiation was amplified by XE991 and tolbutamide. In conclusion, the sAHP shapes intrinsic burst-like firing which, under physiological circumstances, could be controlled via cholinergic afferents and ATP metabolism.
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Affiliation(s)
- Debora Laker
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Frederik Tolle
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Michael Stegen
- Department of Neurosurgery, University of Freiburg, Germany
| | - Marco Heerdegen
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany.
| | - Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University Medicine Rostock, Rostock, Germany
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21
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Springer K, Varghese N, Tzingounis AV. Flexible Stoichiometry: Implications for KCNQ2- and KCNQ3-Associated Neurodevelopmental Disorders. Dev Neurosci 2021; 43:191-200. [PMID: 33794528 PMCID: PMC8440324 DOI: 10.1159/000515495] [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: 12/15/2020] [Accepted: 02/25/2021] [Indexed: 11/19/2022] Open
Abstract
KCNQ2 and KCNQ3 pathogenic channel variants have been associated with a spectrum of developmentally regulated diseases that vary in age of onset, severity, and whether it is transient (i.e., benign familial neonatal seizures) or long-lasting (i.e., developmental and epileptic encephalopathy). KCNQ2 and KCNQ3 channels have also emerged as a target for novel antiepileptic drugs as their activation could reduce epileptic activity. Consequently, a great effort has taken place over the last 2 decades to understand the mechanisms that control the assembly, gating, and modulation of KCNQ2 and KCNQ3 channels. The current view that KCNQ2 and KCNQ3 channels assemble as heteromeric channels (KCNQ2/3) forms the basis of our understanding of KCNQ2 and KCNQ3 channelopathies and drug design. Here, we review the evidence that supports the formation of KCNQ2/3 heteromers in neurons. We also highlight functional and transcriptomic studies that suggest channel composition might not be necessarily fixed in the nervous system, but rather is dynamic and flexible, allowing some neurons to express KCNQ2 and KCNQ3 homomers. We propose that to fully understand KCNQ2 and KCNQ3 channelopathies, we need to adopt a more flexible view of KCNQ2 and KCNQ3 channel stoichiometry, which might differ across development, brain regions, cell types, and disease states.
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Affiliation(s)
- Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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22
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Varghese N, Lauritano A, Taglialatela M, Tzingounis AV. KCNQ3 is the principal target of retigabine in CA1 and subicular excitatory neurons. J Neurophysiol 2021; 125:1440-1449. [PMID: 33729829 DOI: 10.1152/jn.00564.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Retigabine is a first-in-class potassium channel opener approved for patients with epilepsy. Unfortunately, several side effects have limited its use in clinical practice, overshadowing its beneficial effects. Multiple studies have shown that retigabine acts by enhancing the activity of members of the voltage-gated KCNQ (Kv7) potassium channel family, particularly the neuronal KCNQ channels KCNQ2-KCNQ5. However, it is currently unknown whether retigabine's action in neurons is mediated by all KCNQ neuronal channels or by only a subset. This knowledge is necessary to elucidate retigabine's mechanism of action in the central nervous system and its adverse effects and to design more effective and selective retigabine analogs. In this study, we show that the action of retigabine in excitatory neurons strongly depends on the presence of KCNQ3 channels. Deletion of Kcnq3 severely limited the ability of retigabine to reduce neuronal excitability in mouse CA1 and subiculum excitatory neurons. In addition, we report that in the absence of KCNQ3 channels, retigabine can enhance CA1 pyramidal neuron activity, leading to a greater number of action potentials and reduced spike frequency adaptation; this finding further supports a key role of KCNQ3 channels in mediating the action of retigabine. Our work provides new insight into the action of retigabine in forebrain neurons, clarifying retigabine's action in the nervous system.NEW & NOTEWORTHY Retigabine has risen to prominence as a first-in-class potassium channel opener approved by the Food and Drug Administration, with potential for treating multiple neurological disorders. Here, we demonstrate that KCNQ3 channels are the primary target of retigabine in excitatory neurons, as deleting these channels greatly diminishes the effect of retigabine in pyramidal neurons. Our data provide the first indication that retigabine controls neuronal firing properties primarily through KCNQ3 channels.
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Affiliation(s)
- Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Anna Lauritano
- Department of Neuroscience, University of Naples Federico II, Naples, Italy
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23
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Simkin D, Marshall KA, Vanoye CG, Desai RR, Bustos BI, Piyevsky BN, Ortega JA, Forrest M, Robertson GL, Penzes P, Laux LC, Lubbe SJ, Millichap JJ, George AL, Kiskinis E. Dyshomeostatic modulation of Ca 2+-activated K + channels in a human neuronal model of KCNQ2 encephalopathy. eLife 2021; 10:64434. [PMID: 33544076 PMCID: PMC7864629 DOI: 10.7554/elife.64434] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/20/2021] [Indexed: 12/22/2022] Open
Abstract
Mutations in KCNQ2, which encodes a pore-forming K+ channel subunit responsible for neuronal M-current, cause neonatal epileptic encephalopathy, a complex disorder presenting with severe early-onset seizures and impaired neurodevelopment. The condition is exceptionally difficult to treat, partially because the effects of KCNQ2 mutations on the development and function of human neurons are unknown. Here, we used induced pluripotent stem cells (iPSCs) and gene editing to establish a disease model and measured the functional properties of differentiated excitatory neurons. We find that patient iPSC-derived neurons exhibit faster action potential repolarization, larger post-burst afterhyperpolarization and a functional enhancement of Ca2+-activated K+ channels. These properties, which can be recapitulated by chronic inhibition of M-current in control neurons, facilitate a burst-suppression firing pattern that is reminiscent of the interictal electroencephalography pattern in patients. Our findings suggest that dyshomeostatic mechanisms compound KCNQ2 loss-of-function leading to alterations in the neurodevelopmental trajectory of patient iPSC-derived neurons.
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Affiliation(s)
- Dina Simkin
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Kelly A Marshall
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Carlos G Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Reshma R Desai
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Bernabe I Bustos
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Brandon N Piyevsky
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Juan A Ortega
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Marc Forrest
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Gabriella L Robertson
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Peter Penzes
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Center for Autism and Neurodevelopment, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Linda C Laux
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Steven J Lubbe
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - John J Millichap
- Epilepsy Center and Division of Neurology, Departments of Pediatrics and Neurology, Ann & Robert H. Lurie Children's Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Alfred L George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, United States
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, United States.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, United States
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24
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Miceli F, Carotenuto L, Barrese V, Soldovieri MV, Heinzen EL, Mandel AM, Lippa N, Bier L, Goldstein DB, Cooper EC, Cilio MR, Taglialatela M, Sands TT. A Novel Kv7.3 Variant in the Voltage-Sensing S 4 Segment in a Family With Benign Neonatal Epilepsy: Functional Characterization and in vitro Rescue by β-Hydroxybutyrate. Front Physiol 2020; 11:1040. [PMID: 33013448 PMCID: PMC7498716 DOI: 10.3389/fphys.2020.01040] [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: 06/05/2020] [Accepted: 07/29/2020] [Indexed: 01/09/2023] Open
Abstract
Pathogenic variants in KCNQ2 and KCNQ3, paralogous genes encoding Kv7.2 and Kv7.3 voltage-gated K+ channel subunits, are responsible for early-onset developmental/epileptic disorders characterized by heterogeneous clinical phenotypes ranging from benign familial neonatal epilepsy (BFNE) to early-onset developmental and epileptic encephalopathy (DEE). KCNQ2 variants account for the majority of pedigrees with BFNE and KCNQ3 variants are responsible for a much smaller subgroup, but the reasons for this imbalance remain unclear. Analysis of additional pedigrees is needed to further clarify the nature of this genetic heterogeneity and to improve prediction of pathogenicity for novel variants. We identified a BFNE family with two siblings and a parent affected. Exome sequencing on samples from both parents and siblings revealed a novel KCNQ3 variant (c.719T>G; p.M240R), segregating in the three affected individuals. The M240 residue is conserved among human Kv7.2-5 and lies between the two arginines (R5 and R6) closest to the intracellular side of the voltage-sensing S4 transmembrane segment. Whole cell patch-clamp recordings in Chinese hamster ovary (CHO) cells revealed that homomeric Kv7.3 M240R channels were not functional, whereas heteromeric channels incorporating Kv7.3 M240R mutant subunits with Kv7.2 and Kv7.3 displayed a depolarizing shift of about 10 mV in activation gating. Molecular modeling results suggested that the M240R substitution preferentially stabilized the resting state and possibly destabilized the activated state of the Kv7.3 subunits, a result consistent with functional data. Exposure to β-hydroxybutyrate (BHB), a ketone body generated during the ketogenic diet (KD), reversed channel dysfunction induced by the M240R variant. In conclusion, we describe the first missense loss-of-function (LoF) pathogenic variant within the S4 segment of Kv7.3 identified in patients with BFNE. Studied under conditions mimicking heterozygosity, the M240R variant mainly affects the voltage sensitivity, in contrast to previously analyzed BFNE Kv7.3 variants that reduce current density. Our pharmacological results provide a rationale for the use of KD in patients carrying LoF variants in Kv7.2 or Kv7.3 subunits.
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Affiliation(s)
- Francesco Miceli
- Department of Neuroscience, University of Naples “Federico II”, Naples, Italy
| | - Lidia Carotenuto
- Department of Neuroscience, University of Naples “Federico II”, Naples, Italy
| | - Vincenzo Barrese
- Department of Neuroscience, University of Naples “Federico II”, Naples, Italy
| | | | - Erin L. Heinzen
- Eshelman School of Pharmacy, Division of Pharmacotherapy and Experimental Therapeutics, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Arthur M. Mandel
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
| | - Natalie Lippa
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Louise Bier
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - David B. Goldstein
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Edward C. Cooper
- Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Maria Roberta Cilio
- Department of Pediatrics and Institute of Experimental and Clinical Research, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | | | - Tristan T. Sands
- Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, United States
- Department of Neurology, Columbia University Irving Medical Center, New York, NY, United States
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25
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Vigil FA, Carver CM, Shapiro MS. Pharmacological Manipulation of K v 7 Channels as a New Therapeutic Tool for Multiple Brain Disorders. Front Physiol 2020; 11:688. [PMID: 32636759 PMCID: PMC7317068 DOI: 10.3389/fphys.2020.00688] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 05/27/2020] [Indexed: 12/12/2022] Open
Abstract
K v 7 ("M-type," KCNQ) K+ currents, play dominant roles in controlling neuronal excitability. They act as a "brake" against hyperexcitable states in the central and peripheral nervous systems. Pharmacological augmentation of M current has been developed for controlling epileptic seizures, although current pharmacological tools are uneven in practical usefulness. Lately, however, M-current "opener" compounds have been suggested to be efficacious in preventing brain damage after multiple types of insults/diseases, such as stroke, traumatic brain injury, drug addiction and mood disorders. In this review, we will discuss what is known to date on these efforts and identify gaps in our knowledge regarding the link between M current and therapeutic potential for these disorders. We will outline the preclinical experiments that are yet to be performed to demonstrate the likelihood of success of this approach in human trials. Finally, we also address multiple pharmacological tools available to manipulate different K v 7 subunits and the relevant evidence for translational application in the clinical use for disorders of the central nervous system and multiple types of brain insults. We feel there to be great potential for manipulation of K v 7 channels as a novel therapeutic mode of intervention in the clinic, and that the paucity of existing therapies obligates us to perform further research, so that patients can soon benefit from such therapeutic approaches.
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Affiliation(s)
- Fabio A Vigil
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Chase M Carver
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Mark S Shapiro
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
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26
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Nappi P, Miceli F, Soldovieri MV, Ambrosino P, Barrese V, Taglialatela M. Epileptic channelopathies caused by neuronal Kv7 (KCNQ) channel dysfunction. Pflugers Arch 2020; 472:881-898. [PMID: 32506321 DOI: 10.1007/s00424-020-02404-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 05/12/2020] [Accepted: 05/18/2020] [Indexed: 11/28/2022]
Abstract
Seizures are the most common neurological manifestation in the newborn period, with an estimated incidence of 1.8-3.5 per 1000 live births. Prolonged or intractable seizures have a detrimental effect on cognition and brain function in experimental animals and are associated with adverse long-term neurodevelopmental sequelae and an increased risk of post-neonatal epilepsy in humans. The developing brain is particularly susceptible to the potentially severe effects of epilepsy, and epilepsy, especially when refractory to medications, often results in a developmental and epileptic encephalopathy (DEE) with developmental arrest or regression. DEEs can be primarily attributed to genetic causes. Given the critical role of potassium (K+) currents with distinct subcellular localization, biophysical properties, modulation, and pharmacological profile in regulating intrinsic electrical properties of neurons and their responsiveness to synaptic inputs, it is not too surprising that genetic research in the past two decades has identified several K+ channel genes as responsible for a large fraction of DEE. In the present article, we review the genetically determined epileptic channelopathies affecting three members of the Kv7 family, namely Kv7.2 (KCNQ2), Kv7.3 (KCNQ3), and Kv7.5 (KCNQ5); we review the phenotypic spectrum of Kv7-related epileptic channelopathies, the different genetic and pathogenetic mechanisms, and the emerging genotype-phenotype correlations which may prove crucial for prognostic predictions, disease management, parental counseling, and individually tailored therapeutic attempts.
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Affiliation(s)
- Piera Nappi
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Francesco Miceli
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy
| | | | - Paolo Ambrosino
- Department of Science and Technology (DST), University of Sannio, Benevento, Italy
| | - Vincenzo Barrese
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy
| | - Maurizio Taglialatela
- Section of Pharmacology, Department of Neuroscience, University of Naples, "Federico II", Via Pansini 5, 80131, Naples, Italy.
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27
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Tubert C, Murer MG. What’s wrong with the striatal cholinergic interneurons in Parkinson’s disease? Focus on intrinsic excitability. Eur J Neurosci 2020; 53:2100-2116. [DOI: 10.1111/ejn.14742] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/04/2020] [Accepted: 04/05/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Cecilia Tubert
- Instituto de Fisiología y Biofísica “Bernardo Houssay”, (IFIBIO‐Houssay) Grupo de Neurociencia de Sistemas Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires Argentina
| | - Mario Gustavo Murer
- Instituto de Fisiología y Biofísica “Bernardo Houssay”, (IFIBIO‐Houssay) Grupo de Neurociencia de Sistemas Universidad de Buenos Aires y Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) Buenos Aires Argentina
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28
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Liou JY, Smith EH, Bateman LM, Bruce SL, McKhann GM, Goodman RR, Emerson RG, Schevon CA, Abbott LF. A model for focal seizure onset, propagation, evolution, and progression. eLife 2020; 9:50927. [PMID: 32202494 PMCID: PMC7089769 DOI: 10.7554/elife.50927] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 03/04/2020] [Indexed: 12/16/2022] Open
Abstract
We developed a neural network model that can account for major elements common to human focal seizures. These include the tonic-clonic transition, slow advance of clinical semiology and corresponding seizure territory expansion, widespread EEG synchronization, and slowing of the ictal rhythm as the seizure approaches termination. These were reproduced by incorporating usage-dependent exhaustion of inhibition in an adaptive neural network that receives global feedback inhibition in addition to local recurrent projections. Our model proposes mechanisms that may underline common EEG seizure onset patterns and status epilepticus, and postulates a role for synaptic plasticity in the emergence of epileptic foci. Complex patterns of seizure activity and bi-stable seizure end-points arise when stochastic noise is included. With the rapid advancement of clinical and experimental tools, we believe that this model can provide a roadmap and potentially an in silico testbed for future explorations of seizure mechanisms and clinical therapies.
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Affiliation(s)
- Jyun-You Liou
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States.,Department of Anesthesiology, NewYork-Presbyterian Hospital/Weill Cornell Medicine, New York, United States.,Department of Neurology, Columbia University Medical Center, New York, United States
| | - Elliot H Smith
- Department of Neurological Surgery, Columbia University Medical Center, New York, United States
| | - Lisa M Bateman
- Department of Neurology, Columbia University Medical Center, New York, United States
| | - Samuel L Bruce
- Vagelos College of Physicians & Surgeons, Columbia University, New York, United States
| | - Guy M McKhann
- Department of Neurological Surgery, Columbia University Medical Center, New York, United States
| | - Robert R Goodman
- Department of Neurological Surgery, Columbia University Medical Center, New York, United States
| | - Ronald G Emerson
- Department of Neurology, Columbia University Medical Center, New York, United States
| | - Catherine A Schevon
- Department of Neurology, Columbia University Medical Center, New York, United States
| | - L F Abbott
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States.,Mortimer B. Zuckerman Mind Brain Behavior Institute, Department of Neuroscience, Columbia University, New York, United States
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29
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Perturbed Ca2+-dependent signaling of DYT2 hippocalcin mutant as mechanism of autosomal recessive dystonia. Neurobiol Dis 2019; 132:104529. [DOI: 10.1016/j.nbd.2019.104529] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/22/2019] [Accepted: 07/09/2019] [Indexed: 11/23/2022] Open
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30
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Carver CM, Hastings SD, Cook ME, Shapiro MS. Functional responses of the hippocampus to hyperexcitability depend on directed, neuron-specific KCNQ2 K + channel plasticity. Hippocampus 2019; 30:435-455. [PMID: 31621989 DOI: 10.1002/hipo.23163] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/24/2019] [Accepted: 08/30/2019] [Indexed: 12/14/2022]
Abstract
M-type (KCNQ2/3) K+ channels play dominant roles in regulation of active and passive neuronal discharge properties such as resting membrane potential, spike-frequency adaptation, and hyper-excitatory states. However, plasticity of M-channel expression and function in nongenetic forms of epileptogenesis are still not well understood. Using transgenic mice with an EGFP reporter to detect expression maps of KCNQ2 mRNA, we assayed hyperexcitability-induced alterations in KCNQ2 transcription across subregions of the hippocampus. Pilocarpine and pentylenetetrazol chemoconvulsant models of seizure induction were used, and brain tissue examined 48 hr later. We observed increases in KCNQ2 mRNA in CA1 and CA3 pyramidal neurons after chemoconvulsant-induced hyperexcitability at 48 hr, but no significant change was observed in dentate gyrus (DG) granule cells. Using chromogenic in situ hybridization assays, changes to KCNQ3 transcription were not detected after hyper-excitation challenge, but the results for KCNQ2 paralleled those using the KCNQ2-mRNA reporter mice. In mice 7 days after pilocarpine challenge, levels of KCNQ2 mRNA were similar in all regions to those from control mice. In brain-slice electrophysiology recordings, CA1 pyramidal neurons demonstrated increased M-current amplitudes 48 hr after hyperexcitability; however, there were no significant changes to DG granule cell M-current amplitude. Traumatic brain injury induced significantly greater KCNQ2 expression in the hippocampal hemisphere that was ipsilateral to the trauma. In vivo, after a secondary challenge with subconvulsant dose of pentylenetetrazole, control mice were susceptible to tonic-clonic seizures, whereas mice administered the M-channel opener retigabine were protected from such seizures. This study demonstrates that increased excitatory activity promotes KCNQ2 upregulation in the hippocampus in a cell-type specific manner. Such novel ion channel expressional plasticity may serve as a compensatory mechanism after a hyperexcitable event, at least in the short term. The upregulation described could be potentially leveraged in anticonvulsant enhancement of KCNQ2 channels as therapeutic target for preventing onset of epileptogenic seizures.
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Affiliation(s)
- Chase M Carver
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
| | - Shayne D Hastings
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
| | - Mileah E Cook
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
| | - Mark S Shapiro
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, Texas
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31
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Junctophilin Proteins Tether a Cav1-RyR2-KCa3.1 Tripartite Complex to Regulate Neuronal Excitability. Cell Rep 2019; 28:2427-2442.e6. [DOI: 10.1016/j.celrep.2019.07.075] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/20/2019] [Accepted: 07/19/2019] [Indexed: 12/12/2022] Open
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32
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Kim EC, Patel J, Zhang J, Soh H, Rhodes JS, Tzingounis AV, Chung HJ. Heterozygous loss of epilepsy gene KCNQ2 alters social, repetitive and exploratory behaviors. GENES BRAIN AND BEHAVIOR 2019; 19:e12599. [PMID: 31283873 PMCID: PMC7050516 DOI: 10.1111/gbb.12599] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 06/28/2019] [Accepted: 07/06/2019] [Indexed: 12/28/2022]
Abstract
KCNQ/Kv7 channels conduct voltage‐dependent outward potassium currents that potently decrease neuronal excitability. Heterozygous inherited mutations in their principle subunits Kv7.2/KCNQ2 and Kv7.3/KCNQ3 cause benign familial neonatal epilepsy whereas patients with de novo heterozygous Kv7.2 mutations are associated with early‐onset epileptic encephalopathy and neurodevelopmental disorders characterized by intellectual disability, developmental delay and autism. However, the role of Kv7.2‐containing Kv7 channels in behaviors especially autism‐associated behaviors has not been described. Because pathogenic Kv7.2 mutations in patients are typically heterozygous loss‐of‐function mutations, we investigated the contributions of Kv7.2 to exploratory, social, repetitive and compulsive‐like behaviors by behavioral phenotyping of both male and female KCNQ2+/− mice that were heterozygous null for the KCNQ2 gene. Compared with their wild‐type littermates, male and female KCNQ2+/− mice displayed increased locomotor activity in their home cage during the light phase but not the dark phase and showed no difference in motor coordination, suggesting hyperactivity during the inactive light phase. In the dark phase, KCNQ2+/− group showed enhanced exploratory behaviors, and repetitive grooming but decreased sociability with sex differences in the degree of these behaviors. While male KCNQ2+/− mice displayed enhanced compulsive‐like behavior and social dominance, female KCNQ2+/− mice did not. In addition to elevated seizure susceptibility, our findings together indicate that heterozygous loss of Kv7.2 induces behavioral abnormalities including autism‐associated behaviors such as reduced sociability and enhanced repetitive behaviors. Therefore, our study is the first to provide a tangible link between loss‐of‐function Kv7.2 mutations and the behavioral comorbidities of Kv7.2‐associated epilepsy.
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Affiliation(s)
- Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Jaimin Patel
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Justin S Rhodes
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Department of Psychology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
| | | | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois.,Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois
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33
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Balint B, Charlesworth G, Erro R, Wood NW, Bhatia KP. Delineating the phenotype of autosomal-recessive HPCA mutations: Not only isolated dystonia! Mov Disord 2019; 34:589-592. [DOI: 10.1002/mds.27638] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 11/14/2018] [Indexed: 11/09/2022] Open
Affiliation(s)
- Bettina Balint
- Department of Motor Neuroscience and Movement Disorders; UCL Queen Square Institute of Neurology; London United Kingdom
- Department of Neurology; University Hospital Heidelberg; Germany
| | | | - Roberto Erro
- Center for Neurodegenerative Diseases (CEMAND), Department of Medicine, Surgery and Dentistry “Scuola Medica Salernitana”; University of Salerno; Baronissi (SA) Italy
| | - Nicholas W. Wood
- Department of Molecular Neuroscience; Institute of Neurology, University College London; London United Kingdom
| | - Kailash P. Bhatia
- Department of Motor Neuroscience and Movement Disorders; UCL Queen Square Institute of Neurology; London United Kingdom
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34
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Abstract
Voltage-gated potassium (Kv) channels open in response to changes in membrane potential to permit passage of K+ ions across the cell membrane, down their electrochemical gradient. Sodium-coupled solute transporters utilize the downhill sodium gradient to co-transport solutes, ranging from ions to sugars to neurotransmitters, into the cell. A variety of recent studies have uncovered cooperation between these two structurally and functionally unrelated classes of protein, revealing previously unnoticed functional crosstalk and in many cases physical interaction to form channel-transporter (chansporter) complexes. Adding to this field, Bartolomé-Martín and colleagues now report that the heteromeric KCNQ2/KCNQ3 (Kv7.2/7.3) potassium channel - the primary molecular correlate of the neuronal M-current - can physically interact with two sodium-coupled neurotransmitter transporters expressed in the brain, DAT and GLT1 (dopamine and glutamate transporters, respectively). The authors provide evidence that the interactions may enhance transporter activity while dampening the depolarizing effects of sodium influx. Cumulative evidence discussed here suggests that chansporter complexes represent a widespread form of cellular signaling hub, in the CNS and other tissues. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Rían W Manville
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Dept. of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA, USA.
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35
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Kang S, Li J, Zuo W, Chen P, Gregor D, Fu R, Han X, Bekker A, Ye JH. Downregulation of M-channels in lateral habenula mediates hyperalgesia during alcohol withdrawal in rats. Sci Rep 2019; 9:2714. [PMID: 30804373 PMCID: PMC6389965 DOI: 10.1038/s41598-018-38393-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 12/21/2018] [Indexed: 01/21/2023] Open
Abstract
Hyperalgesia often occurs in alcoholics, especially during abstinence, yet the underlying mechanisms remain elusive. The lateral habenula (LHb) has been implicated in the pathophysiology of pain and alcohol use disorders. Suppression of m-type potassium channels (M-channels) has been found to contribute to the hyperactivity of LHb neurons of rats withdrawn from chronic alcohol administration. Here, we provided evidence that LHb M-channels may contribute to hyperalgesia. Compared to alcohol naïve counterparts, in male Long-Evans rats at 24-hours withdrawal from alcohol administration under the intermittent access paradigm for eight weeks, hyperalgesia was evident (as measured by paw withdrawal latencies in the Hargreaves Test), which was accompanied with higher basal activities of LHb neurons in brain slices, and lower M-channel protein expression. Inhibition of LHb neurons by chemogenetics, or pharmacological activation of M-channels, as well as overexpression of M-channels' subunit KCNQ3, relieved hyperalgesia and decreased relapse-like alcohol consumption. In contrast, chemogenetic activation of LHb neurons induced hyperalgesia in alcohol-naive rats. These data reveal a central role for the LHb in hyperalgesia during alcohol withdrawal, which may be due in part to the suppression of M-channels and, thus, highlights M-channels in the LHb as a potential therapeutic target for hyperalgesia in alcoholics.
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Affiliation(s)
- Seungwoo Kang
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Jing Li
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Wanhong Zuo
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Pei Chen
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Danielle Gregor
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Rao Fu
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Xiao Han
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Alex Bekker
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Jiang-Hong Ye
- Department of Anesthesiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA. .,Pharmacology, Physiology, and Neuroscience, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA.
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36
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Gq-Coupled Muscarinic Receptor Enhancement of KCNQ2/3 Channels and Activation of TRPC Channels in Multimodal Control of Excitability in Dentate Gyrus Granule Cells. J Neurosci 2018; 39:1566-1587. [PMID: 30593498 DOI: 10.1523/jneurosci.1781-18.2018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 12/21/2022] Open
Abstract
KCNQ (Kv7, "M-type") K+ channels and TRPC (transient receptor potential, "canonical") cation channels are coupled to neuronal discharge properties and are regulated via Gq/11-protein-mediated signals. Stimulation of Gq/11-coupled receptors both consumes phosphatidylinositol 4,5-bisphosphate (PIP2) via phosphalipase Cβ hydrolysis and stimulates PIP2 synthesis via rises in Ca2+ i and other signals. Using brain-slice electrophysiology and Ca2+ imaging from male and female mice, we characterized threshold K+ currents in dentate gyrus granule cells (DGGCs) and CA1 pyramidal cells, the effects of Gq/11-coupled muscarinic M1 acetylcholine (M1R) stimulation on M current and on neuronal discharge properties, and elucidated the intracellular signaling mechanisms involved. We observed disparate signaling cascades between DGGCs and CA1 neurons. DGGCs displayed M1R enhancement of M-current, rather than suppression, due to stimulation of PIP2 synthesis, which was paralleled by increased PIP2-gated G-protein coupled inwardly rectifying K+ currents as well. Deficiency of KCNQ2-containing M-channels ablated the M1R-induced enhancement of M-current in DGGCs. Simultaneously, M1R stimulation in DGGCs induced robust increases in [Ca2+]i, mostly due to TRPC currents, consistent with, and contributing to, neuronal depolarization and hyperexcitability. CA1 neurons did not display such multimodal signaling, but rather M current was suppressed by M1R stimulation in these cells, similar to the previously described actions of M1R stimulation on M-current in peripheral ganglia that mostly involves PIP2 depletion. Therefore, these results point to a pleiotropic network of cholinergic signals that direct cell-type-specific, precise control of hippocampal function with strong implications for hyperexcitability and epilepsy.SIGNIFICANCE STATEMENT At the neuronal membrane, protein signaling cascades consisting of ion channels and metabotropic receptors govern the electrical properties and neurotransmission of neuronal networks. Muscarinic acetylcholine receptors are G-protein-coupled metabotropic receptors that control the excitability of neurons through regulating ion channels, intracellular Ca2+ signals, and other second-messenger cascades. We have illuminated previously unknown actions of muscarinic stimulation on the excitability of hippocampal principal neurons that include M channels, TRPC (transient receptor potential, "canonical") cation channels, and powerful regulation of lipid metabolism. Our results show that these signaling pathways, and mechanisms of excitability, are starkly distinct between peripheral ganglia and brain, and even between different principal neurons in the hippocampus.
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37
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Diao Y, Yan W, Sun W, Luo Y, Li J, Yin Y. The dual role of KCNQ/M channels upon OGD or OGD/R insults in cultured cortical neurons of mice: Timing is crucial in targeting M-channels against ischemic injur ies. J Cell Physiol 2018; 234:12714-12726. [PMID: 30523632 DOI: 10.1002/jcp.27889] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/13/2018] [Indexed: 01/09/2023]
Abstract
KCNQ/M potassium channels play a vital role in neuronal excitability; however, it is required to explore their pharmacological modulation on N-Methyl- d-aspartic acid receptors (NMDARs)-mediated glutamatergic transmission of neurons upon ischemic insults. In the current study, both presynaptic glutamatergic release and activities of NMDARs were measured by NMDAR-induced miniature excitatory postsynaptic currents (mEPSCs) in cultured cortical neurons of C57 mice undergoing oxygen and glucose deprivation (OGD) or OGD/reperfusion (OGD/R). The KCNQ/M-channel opener, retigabine (RTG), suppressed the overactivation of postsynaptic NMDARs induced by OGD and then NO transient; RTG also decreased OGD-induced neuronal death measured with MTT assay, suggesting the beneficial role of KCNQ/M-channels for the neurons exposed to ischemic insults. However, when the neurons exposed to the subsequent reperfusion, KCNQ/M-channels played a differential role from its protective effect. OGD/R increased presynaptic glutamatergic release, which was further augmented by RTG or decreased by KCNQ/M-channel blocker, XE991. Reactive oxygen species (ROS) were produced partly in a NO-dependent manner. In addition, XE991 decreased neuronal injuries upon reperfusion measured with DCF and PI staining. Meanwhile, the addition of RTG upon OGD or XE991 upon reperfusion can reverse OGD or OGD/R-reduced mitochondrial membrane potential. Our present study indicates the dual role of KCNQ/M-channels in OGD and OGD/R, which will decide the fate of neurons. Provided that activation of KCNQ/M-channels has differential effects on neuronal injuries during OGD or OGD/R, we propose that therapy targeting KCNQ/M-channels may be effective for ischemic injuries but the proper timing is so crucial for the corresponding treatment.
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Affiliation(s)
- Yu Diao
- Department of Neurobiology, Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Weijie Yan
- Department of Neurobiology, Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Wei Sun
- Department of Neurology, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yanlin Luo
- Department of Neurobiology, Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Junfa Li
- Department of Neurobiology, Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, School of Basic Medical Sciences, Capital Medical University, Beijing, China
| | - Yanling Yin
- Department of Neurobiology, Key Laboratory for Neurodegenerative Disorders of the Ministry of Education, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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38
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Kshatri AS, Gonzalez-Hernandez A, Giraldez T. Physiological Roles and Therapeutic Potential of Ca 2+ Activated Potassium Channels in the Nervous System. Front Mol Neurosci 2018; 11:258. [PMID: 30104956 PMCID: PMC6077210 DOI: 10.3389/fnmol.2018.00258] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/06/2018] [Indexed: 12/21/2022] Open
Abstract
Within the potassium ion channel family, calcium activated potassium (KCa) channels are unique in their ability to couple intracellular Ca2+ signals to membrane potential variations. KCa channels are diversely distributed throughout the central nervous system and play fundamental roles ranging from regulating neuronal excitability to controlling neurotransmitter release. The physiological versatility of KCa channels is enhanced by alternative splicing and co-assembly with auxiliary subunits, leading to fundamental differences in distribution, subunit composition and pharmacological profiles. Thus, understanding specific KCa channels’ mechanisms in neuronal function is challenging. Based on their single channel conductance, KCa channels are divided into three subtypes: small (SK, 4–14 pS), intermediate (IK, 32–39 pS) and big potassium (BK, 200–300 pS) channels. This review describes the biophysical characteristics of these KCa channels, as well as their physiological roles and pathological implications. In addition, we also discuss the current pharmacological strategies and challenges to target KCa channels for the treatment of various neurological and psychiatric disorders.
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Affiliation(s)
- Aravind S Kshatri
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
| | - Alberto Gonzalez-Hernandez
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
| | - Teresa Giraldez
- Department of Basic Medical Sciences, Medical School, Universidad de La Laguna, Tenerife, Spain.,Instituto de Tecnologias Biomedicas, Universidad de La Laguna, Tenerife, Spain
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39
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Kim EC, Zhang J, Pang W, Wang S, Lee KY, Cavaretta JP, Walters J, Procko E, Tsai NP, Chung HJ. Reduced axonal surface expression and phosphoinositide sensitivity in K v7 channels disrupts their function to inhibit neuronal excitability in Kcnq2 epileptic encephalopathy. Neurobiol Dis 2018; 118:76-93. [PMID: 30008368 DOI: 10.1016/j.nbd.2018.07.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/22/2018] [Accepted: 07/04/2018] [Indexed: 01/08/2023] Open
Abstract
Neuronal Kv7/KCNQ channels are voltage-gated potassium channels composed of Kv7.2/KCNQ2 and Kv7.3/KCNQ3 subunits. Enriched at the axonal membrane, they potently suppress neuronal excitability. De novo and inherited dominant mutations in Kv7.2 cause early onset epileptic encephalopathy characterized by drug resistant seizures and profound psychomotor delay. However, their precise pathogenic mechanisms remain elusive. Here, we investigated selected epileptic encephalopathy causing mutations in calmodulin (CaM)-binding helices A and B of Kv7.2. We discovered that R333W, K526N, and R532W mutations located peripheral to CaM contact sites decreased axonal surface expression of heteromeric channels although only R333W mutation reduced CaM binding to Kv7.2. These mutations also altered gating modulation by phosphatidylinositol 4,5-bisphosphate (PIP2), revealing novel PIP2 binding residues. While these mutations disrupted Kv7 function to suppress excitability, hyperexcitability was observed in neurons expressing Kv7.2-R532W that displayed severe impairment in voltage-dependent activation. The M518 V mutation at the CaM contact site in helix B caused most defects in Kv7 channels by severely reducing their CaM binding, K+ currents, and axonal surface expression. Interestingly, the M518 V mutation induced ubiquitination and accelerated proteasome-dependent degradation of Kv7.2, whereas the presence of Kv7.3 blocked this degradation. Furthermore, expression of Kv7.2-M518V increased neuronal death. Together, our results demonstrate that epileptic encephalopathy mutations in helices A and B of Kv7.2 cause abnormal Kv7 expression and function by disrupting Kv7.2 binding to CaM and/or modulation by PIP2. We propose that such multiple Kv7 channel defects could exert more severe impacts on neuronal excitability and health, and thus serve as pathogenic mechanisms underlying Kcnq2 epileptic encephalopathy.
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Affiliation(s)
- Eung Chang Kim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jiaren Zhang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Weilun Pang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Shuwei Wang
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Kwan Young Lee
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - John P Cavaretta
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jennifer Walters
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Erik Procko
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Nien-Pei Tsai
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hee Jung Chung
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
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40
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Tiwari MN, Mohan S, Biala Y, Yaari Y. Differential contributions of Ca 2+ -activated K + channels and Na + /K + -ATPases to the generation of the slow afterhyperpolarization in CA1 pyramidal cells. Hippocampus 2018; 28:338-357. [PMID: 29431274 PMCID: PMC5947627 DOI: 10.1002/hipo.22836] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/17/2017] [Accepted: 02/05/2018] [Indexed: 12/13/2022]
Abstract
In many types of CNS neurons, repetitive spiking produces a slow afterhyperpolarization (sAHP), providing sustained, intrinsically generated negative feedback to neuronal excitation. Changes in the sAHP have been implicated in learning behaviors, in cognitive decline in aging, and in epileptogenesis. Despite its importance in brain function, the mechanisms generating the sAHP are still controversial. Here we have addressed the roles of M-type K+ current (IM ), Ca2+ -gated K+ currents (ICa(K) 's) and Na+ /K+ -ATPases (NKAs) current to sAHP generation in adult rat CA1 pyramidal cells maintained at near-physiological temperature (35 °C). No evidence for IM contribution to the sAHP was found in these neurons. Both ICa(K) 's and NKA current contributed to sAHP generation, the latter being the predominant generator of the sAHP, particularly when evoked with short trains of spikes. Of the different NKA isoenzymes, α1 -NKA played the key role, endowing the sAHP a steep voltage-dependence. Thus normal and pathological changes in α1 -NKA expression or function may affect cognitive processes by modulating the inhibitory efficacy of the sAHP.
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Affiliation(s)
- Manindra Nath Tiwari
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
| | - Sandesh Mohan
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
| | - Yoav Biala
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
| | - Yoel Yaari
- Department of Medical Neurobiology; Institute for Medical Research Israel‐CanadaThe Hebrew University‐Hadassah School of MedicineJerusalem91120Israel
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41
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Kim KS, Duignan KM, Hawryluk JM, Soh H, Tzingounis AV. The Voltage Activation of Cortical KCNQ Channels Depends on Global PIP2 Levels. Biophys J 2016; 110:1089-98. [PMID: 26958886 DOI: 10.1016/j.bpj.2016.01.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 01/22/2023] Open
Abstract
The slow afterhyperpolarization (sAHP) is a calcium-activated potassium conductance with critical roles in multiple physiological processes. Pharmacological and genetic data suggest that KCNQ channels partly mediate the sAHP. However, these channels are not typically open within the observed voltage range of the sAHP. Recent work has shown that the sAHP is gated by increased PIP2 levels, which are generated downstream of calcium binding by neuronal calcium sensors such as hippocalcin. Here, we examined whether changes in PIP2 levels could shift the voltage-activation range of KCNQ channels. In HEK293T cells, expression of the PIP5 kinase PIPKIγ90, which increases global PIP2 levels, shifted the KCNQ voltage activation to within the operating range of the sAHP. Further, the sensitivity of this effect on KCNQ3 channels appeared to be higher than that on KCNQ2. Therefore, we predict that KCNQ3 plays an essential role in maintaining the sAHP under low PIP2 conditions. In support of this notion, we find that sAHP inhibition by muscarinic receptors that increase phosphoinositide turnover in neurons is enhanced in Kcnq3-knockout mice. Likewise, the presence of KCNQ3 is essential for maintaining the sAHP when hippocalcin is ablated, a condition that likely impairs PIP2 generation. Together, our results establish the relationship between PIP2 and the voltage dependence of cortical KCNQ channels (KCNQ2/3, KCNQ3/5, and KCNQ5), and suggest a possible mechanism for the involvement of KCNQ channels in the sAHP.
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Affiliation(s)
- Kwang S Kim
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Kevin M Duignan
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Joanna M Hawryluk
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
| | - Heun Soh
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut
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Hypocretin/Orexin Peptides Alter Spike Encoding by Serotonergic Dorsal Raphe Neurons through Two Distinct Mechanisms That Increase the Late Afterhyperpolarization. J Neurosci 2016; 36:10097-115. [PMID: 27683906 DOI: 10.1523/jneurosci.0635-16.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 08/11/2016] [Indexed: 01/02/2023] Open
Abstract
UNLABELLED Orexins (hypocretins) are neuropeptides that regulate multiple homeostatic processes, including reward and arousal, in part by exciting serotonergic dorsal raphe neurons, the major source of forebrain serotonin. Here, using mouse brain slices, we found that, instead of simply depolarizing these neurons, orexin-A altered the spike encoding process by increasing the postspike afterhyperpolarization (AHP) via two distinct mechanisms. This orexin-enhanced AHP (oeAHP) was mediated by both OX1 and OX2 receptors, required Ca(2+) influx, reversed near EK, and decayed with two components, the faster of which resulted from enhanced SK channel activation, whereas the slower component decayed like a slow AHP (sAHP), but was not blocked by UCL2077, an antagonist of sAHPs in some neurons. Intracellular phospholipase C inhibition (U73122) blocked the entire oeAHP, but neither component was sensitive to PKC inhibition or altered PKA signaling, unlike classical sAHPs. The enhanced SK current did not depend on IP3-mediated Ca(2+) release but resulted from A-current inhibition and the resultant spike broadening, which increased Ca(2+) influx and Ca(2+)-induced-Ca(2+) release, whereas the slower component was insensitive to these factors. Functionally, the oeAHP slowed and stabilized orexin-induced firing compared with firing produced by a virtual orexin conductance lacking the oeAHP. The oeAHP also reduced steady-state firing rate and firing fidelity in response to stimulation, without affecting the initial rate or fidelity. Collectively, these findings reveal a new orexin action in serotonergic raphe neurons and suggest that, when orexin is released during arousal and reward, it enhances the spike encoding of phasic over tonic inputs, such as those related to sensory, motor, and reward events. SIGNIFICANCE STATEMENT Orexin peptides are known to excite neurons via slow postsynaptic depolarizations. Here we elucidate a significant new orexin action that increases and prolongs the postspike afterhyperpolarization (AHP) in 5-HT dorsal raphe neurons and other arousal-system neurons. Our mechanistic studies establish involvement of two distinct Ca(2+)-dependent AHP currents dependent on phospholipase C signaling but independent of IP3 or PKC. Our functional studies establish that this action preserves responsiveness to phasic inputs while attenuating responsiveness to tonic inputs. Thus, our findings bring new insight into the actions of an important neuropeptide and indicate that, in addition to producing excitation, orexins can tune postsynaptic excitability to better encode the phasic sensory, motor, and reward signals expected during aroused states.
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Decrease of a Current Mediated by K v 1.3 Channels Causes Striatal Cholinergic Interneuron Hyperexcitability in Experimental Parkinsonism. Cell Rep 2016; 16:2749-2762. [DOI: 10.1016/j.celrep.2016.08.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 06/16/2016] [Accepted: 08/05/2016] [Indexed: 02/05/2023] Open
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Maljevic S, Vejzovic S, Bernhard MK, Bertsche A, Weise S, Döcker M, Lerche H, Lemke JR, Merkenschlager A, Syrbe S. Novel KCNQ3 Mutation in a Large Family with Benign Familial Neonatal Epilepsy: A Rare Cause of Neonatal Seizures. Mol Syndromol 2016; 7:189-196. [PMID: 27781029 DOI: 10.1159/000447461] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Benign familial neonatal seizures (BFNS) present a rare familial epilepsy syndrome caused by genetic alterations in the voltage-gated potassium channels Kv7.2 and Kv7.3, encoded by KCNQ2 and KCNQ3. While most BFNS families carry alterations in KCNQ2, mutations in KCNQ3 appear to be less common. Here, we describe a family with 6 individuals presenting with neonatal focal and generalized seizures. Genetic testing revealed a novel KCNQ3 variant, c.835G>T, cosegregating with seizures in 4 tested individuals. This variant results in a substitution of the highly conserved amino acid valine localized within the pore-forming transmembrane segment S5 (p.V279F). Functional investigations in Xenopus laevis oocytes revealed a loss of function, which supports p.V279F as a pathogenic mutation. When p.V279F was coexpressed with the wild-type (WT) Kv7.2 subunits, the resulting potassium currents were about 10-fold reduced compared to the WT Kv7.3 and Kv7.2 coexpression. Genotype-phenotype correlation shows an incomplete penetrance of p.V279F. Response to antiepileptic treatment was variable, but evaluation of treatment response remained challenging due to the self-limiting character of the disease. The identification of the pathogenic variant helped to avoid unnecessary investigations in affected family members and allowed guided therapy.
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Affiliation(s)
- Snezana Maljevic
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Heidelberg, Germany; The Florey Institute of Neuroscience and Mental Health, Melbourne, Vic., Australia
| | - Sabina Vejzovic
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Heidelberg, Germany
| | - Matthias K Bernhard
- Department of Women and Child Health, Hospital for Children and Adolescents, Heidelberg, Germany
| | - Astrid Bertsche
- Department of Women and Child Health, Hospital for Children and Adolescents, Heidelberg, Germany
| | - Sebastian Weise
- Department of Women and Child Health, Hospital for Children and Adolescents, Heidelberg, Germany
| | - Miriam Döcker
- CeGaT GmbH, Tübingen, University Hospital Heidelberg, Heidelberg, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Heidelberg, Germany
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, Leipzig, Germany
| | - Andreas Merkenschlager
- Department of Women and Child Health, Hospital for Children and Adolescents, Heidelberg, Germany
| | - Steffen Syrbe
- Department of Women and Child Health, Hospital for Children and Adolescents, Heidelberg, Germany; Division of Child Neurology and Inherited Metabolic Diseases, Department of General Pediatrics, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
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45
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Kuo FS, Falquetto B, Chen D, Oliveira LM, Takakura AC, Mulkey DK. In vitro characterization of noradrenergic modulation of chemosensitive neurons in the retrotrapezoid nucleus. J Neurophysiol 2016; 116:1024-35. [PMID: 27306669 DOI: 10.1152/jn.00022.2016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 06/09/2016] [Indexed: 01/08/2023] Open
Abstract
Chemosensitive neurons in the retrotrapezoid nucleus (RTN) regulate breathing in response to CO2/H(+) changes and serve as an integration center for other autonomic centers, including brain stem noradrenergic neurons. Norepinephrine (NE) contributes to respiratory control and chemoreception, and, since disruption of NE signaling may contribute to several breathing disorders, we sought to characterize effects of NE on RTN chemoreception. All neurons included in this study responded similarly to CO2/H(+) but showed differential sensitivity to NE; we found that NE activated (79%), inhibited (7%), or had no effect on activity (14%) of RTN chemoreceptors. The excitatory effect of NE on RTN chemoreceptors was dose dependent, retained in the presence of neurotransmitter receptor blockers, and could be mimicked and blocked by pharmacological manipulation of α1-adrenergic receptors (ARs). In addition, NE-activation was blunted by XE991 (KCNQ channel blocker), and partially occluded the firing response to serotonin, suggesting involvement of KCNQ channels. However, in whole cell voltage clamp, activation of α1-ARs decreased outward current and conductance by what appears to be a mixed effect on multiple channels. The inhibitory effect of NE on RTN chemoreceptors was blunted by an α2-AR antagonist. A third group of RTN chemoreceptors was insensitive to NE. We also found that chemosensitive RTN astrocytes do not respond to NE with a change in voltage or by releasing ATP to enhance activity of chemosensitive neurons. These results indicate NE modulates subsets of RTN chemoreceptors by mechanisms involving α1- and α2-ARs.
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Affiliation(s)
- Fu-Shan Kuo
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut; and
| | - Bárbara Falquetto
- Department of Pharmacology, University of Sao Paulo, Sao Paulo, Brazil
| | - Dawei Chen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut; and
| | - Luiz M Oliveira
- Department of Pharmacology, University of Sao Paulo, Sao Paulo, Brazil
| | - Ana C Takakura
- Department of Pharmacology, University of Sao Paulo, Sao Paulo, Brazil
| | - Daniel K Mulkey
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut; and
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Regulation of excitability in tonic firing substantia gelatinosa neurons of the spinal cord by small-conductance Ca 2+ -activated K + channels. Neuropharmacology 2016; 105:15-24. [DOI: 10.1016/j.neuropharm.2016.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 11/30/2015] [Accepted: 01/03/2016] [Indexed: 01/23/2023]
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47
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Involvement of cellular metabolism in age-related LTP modifications in rat hippocampal slices. Oncotarget 2016; 6:14065-81. [PMID: 26101857 PMCID: PMC4546452 DOI: 10.18632/oncotarget.4188] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 05/12/2015] [Indexed: 11/25/2022] Open
Abstract
Recent studies emphasized crucial role of astrocytic glycogen metabolism in regulation of synaptic transmission and plasticity in young animals. However, the interplay between age-related synaptic plasticity impairments and changes in energetic metabolism remains obscure. To address this issue, we investigated, in hippocampal slices of young (one month) and aged rats (20-22-months), the impact of glycogen degradation inhibition on LTP, mRNA expression for glycogen metabolism enzymes and morphology of dendritic spines. We show that, whereas in young hippocampi, inhibition of glycogen phosphorolysis disrupts the late phase of LTP in the Schaffer collateral-CA1 pathway, in aged rats, blockade of glycogen phosphorylase tends to enhance it. Gene expression for key energy metabolism enzymes, such as glycogen synthase and phosphorylase and glutamine synthetase showed marked differences between young and aged groups and changes in expression of these enzymes preceded plasticity phenomena. Interestingly, in the aged group, a prominent expression of these enzymes was found also in neurons. Concluding, we show that LTP in the considered pathway is differentially modulated by metabolic processes in young and aging animals, indicating a novel venue of studies aiming at preventing cognitive decline during aging.
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48
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Rannals MD, Hamersky GR, Page SC, Campbell MN, Briley A, Gallo RA, Phan BN, Hyde TM, Kleinman JE, Shin JH, Jaffe AE, Weinberger DR, Maher BJ. Psychiatric Risk Gene Transcription Factor 4 Regulates Intrinsic Excitability of Prefrontal Neurons via Repression of SCN10a and KCNQ1. Neuron 2016; 90:43-55. [PMID: 26971948 PMCID: PMC4824652 DOI: 10.1016/j.neuron.2016.02.021] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Revised: 10/09/2015] [Accepted: 02/12/2016] [Indexed: 01/28/2023]
Abstract
Transcription Factor 4 (TCF4) is a clinically pleiotropic gene associated with schizophrenia and Pitt-Hopkins syndrome (PTHS). To gain insight about the neurobiology of TCF4, we created an in vivo model of PTHS by suppressing Tcf4 expression in rat prefrontal neurons immediately prior to neurogenesis. This cell-autonomous genetic insult attenuated neuronal spiking by increasing the afterhyperpolarization. At the molecular level, using a novel technique called iTRAP that combined in utero electroporation and translating ribosome affinity purification, we identified increased translation of two ion channel genes, Kcnq1 and Scn10a. These ion channel candidates were validated by pharmacological rescue and molecular phenocopy. Remarkably, similar excitability deficits were observed in prefrontal neurons from a Tcf4(+/tr) mouse model of PTHS. Thus, we identify TCF4 as a regulator of neuronal intrinsic excitability in part by repression of Kcnq1 and Scn10a and suggest that this molecular function may underlie pathophysiology associated with neuropsychiatric disorders.
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Affiliation(s)
- Matthew D Rannals
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Gregory R Hamersky
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Stephanie Cerceo Page
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Morganne N Campbell
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Aaron Briley
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Ryan A Gallo
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - BaDoi N Phan
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Thomas M Hyde
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neurology and the McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Joel E Kleinman
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neurology and the McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Joo Heon Shin
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Andrew E Jaffe
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Daniel R Weinberger
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Neurology and the McKusick Nathans Institute of Genetic Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Brady J Maher
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA; Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21287, USA; Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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Ihara Y, Tomonoh Y, Deshimaru M, Zhang B, Uchida T, Ishii A, Hirose S. Retigabine, a Kv7.2/Kv7.3-Channel Opener, Attenuates Drug-Induced Seizures in Knock-In Mice Harboring Kcnq2 Mutations. PLoS One 2016; 11:e0150095. [PMID: 26910900 PMCID: PMC4766199 DOI: 10.1371/journal.pone.0150095] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 02/09/2016] [Indexed: 12/30/2022] Open
Abstract
The hetero-tetrameric voltage-gated potassium channel Kv7.2/Kv7.3, which is encoded by KCNQ2 and KCNQ3, plays an important role in limiting network excitability in the neonatal brain. Kv7.2/Kv7.3 dysfunction resulting from KCNQ2 mutations predominantly causes self-limited or benign epilepsy in neonates, but also causes early onset epileptic encephalopathy. Retigabine (RTG), a Kv7.2/ Kv7.3-channel opener, seems to be a rational antiepileptic drug for epilepsies caused by KCNQ2 mutations. We therefore evaluated the effects of RTG on seizures in two strains of knock-in mice harboring different Kcnq2 mutations, in comparison to the effects of phenobarbital (PB), which is the first-line antiepileptic drug for seizures in neonates. The subjects were heterozygous knock-in mice (Kcnq2Y284C/+ and Kcnq2A306T/+) bearing the Y284C or A306T Kcnq2 mutation, respectively, and their wild-type (WT) littermates, at 63–100 days of age. Seizures induced by intraperitoneal injection of kainic acid (KA, 12mg/kg) were recorded using a video-electroencephalography (EEG) monitoring system. Effects of RTG on KA-induced seizures of both strains of knock-in mice were assessed using seizure scores from a modified Racine’s scale and compared with those of PB. The number and total duration of spike bursts on EEG and behaviors monitored by video recording were also used to evaluate the effects of RTG and PB. Both Kcnq2Y284C/+ and Kcnq2A306T/+ mice showed significantly more KA-induced seizures than WT mice. RTG significantly attenuated KA-induced seizure activities in both Kcnq2Y284C/+ and Kcnq2A306T/+ mice, and more markedly than PB. This is the first reported evidence of RTG ameliorating KA-induced seizures in knock-in mice bearing mutations of Kcnq2, with more marked effects than those observed with PB. RTG or other Kv7.2-channel openers may be considered as first-line antiepileptic treatments for epilepsies resulting from KCNQ2 mutations.
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Affiliation(s)
- Yukiko Ihara
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Yuko Tomonoh
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Masanobu Deshimaru
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Bo Zhang
- Department of Biochemistry, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Taku Uchida
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka City, Japan
| | - Atsushi Ishii
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
| | - Shinichi Hirose
- Department of Pediatrics, School of Medicine, Fukuoka University, Fukuoka, Japan
- Central Research Institute for the Molecular Pathomechanisms of Epilepsy, Fukuoka University, Fukuoka City, Japan
- * E-mail:
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50
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Bidlingmaier S, Ha K, Lee NK, Su Y, Liu B. Proteome-wide Identification of Novel Ceramide-binding Proteins by Yeast Surface cDNA Display and Deep Sequencing. Mol Cell Proteomics 2016; 15:1232-45. [PMID: 26729710 DOI: 10.1074/mcp.m115.055954] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Indexed: 11/06/2022] Open
Abstract
Although the bioactive sphingolipid ceramide is an important cell signaling molecule, relatively few direct ceramide-interacting proteins are known. We used an approach combining yeast surface cDNA display and deep sequencing technology to identify novel proteins binding directly to ceramide. We identified 234 candidate ceramide-binding protein fragments and validated binding for 20. Most (17) bound selectively to ceramide, although a few (3) bound to other lipids as well. Several novel ceramide-binding domains were discovered, including the EF-hand calcium-binding motif, the heat shock chaperonin-binding motif STI1, the SCP2 sterol-binding domain, and the tetratricopeptide repeat region motif. Interestingly, four of the verified ceramide-binding proteins (HPCA, HPCAL1, NCS1, and VSNL1) and an additional three candidate ceramide-binding proteins (NCALD, HPCAL4, and KCNIP3) belong to the neuronal calcium sensor family of EF hand-containing proteins. We used mutagenesis to map the ceramide-binding site in HPCA and to create a mutant HPCA that does not bind to ceramide. We demonstrated selective binding to ceramide by mammalian cell-produced wild type but not mutant HPCA. Intriguingly, we also identified a fragment from prostaglandin D2synthase that binds preferentially to ceramide 1-phosphate. The wide variety of proteins and domains capable of binding to ceramide suggests that many of the signaling functions of ceramide may be regulated by direct binding to these proteins. Based on the deep sequencing data, we estimate that our yeast surface cDNA display library covers ∼60% of the human proteome and our selection/deep sequencing protocol can identify target-interacting protein fragments that are present at extremely low frequency in the starting library. Thus, the yeast surface cDNA display/deep sequencing approach is a rapid, comprehensive, and flexible method for the analysis of protein-ligand interactions, particularly for the study of non-protein ligands.
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Affiliation(s)
- Scott Bidlingmaier
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Kevin Ha
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Nam-Kyung Lee
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Yang Su
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
| | - Bin Liu
- From the Department of Anesthesia, UCSF Helen Diller Family Comprehensive Cancer Center, University of California at San Francisco, San Francisco, California 94110
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