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Peltola MA, Kuja-Panula J, Liuhanen J, Võikar V, Piepponen P, Hiekkalinna T, Taira T, Lauri SE, Suvisaari J, Kulesskaya N, Paunio T, Rauvala H. AMIGO-Kv2.1 Potassium Channel Complex Is Associated With Schizophrenia-Related Phenotypes. Schizophr Bull 2016; 42:191-201. [PMID: 26240432 PMCID: PMC4681558 DOI: 10.1093/schbul/sbv105] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The enormous variability in electrical properties of neurons is largely affected by a multitude of potassium channel subunits. Kv2.1 is a widely expressed voltage-dependent potassium channel and an important regulator of neuronal excitability. The Kv2.1 auxiliary subunit AMIGO constitutes an integral part of the Kv2.1 channel complex in brain and regulates the activity of the channel. AMIGO and Kv2.1 localize to the distinct somatodendritic clusters at the neuronal plasma membrane. Here we have created and characterized a mouse line lacking the AMIGO gene. Absence of AMIGO clearly reduced the amount of the Kv2.1 channel protein in mouse brain and altered the electrophysiological properties of neurons. These changes were accompanied by behavioral and pharmacological abnormalities reminiscent of those identified in schizophrenia. Concomitantly, we have detected an association of a rare, population-specific polymorphism of KV2.1 (KCNB1) with human schizophrenia in a genetic isolate enriched with schizophrenia. Our study demonstrates the involvement of AMIGO-Kv2.1 channel complex in schizophrenia-related behavioral domains in mice and identifies KV2.1 (KCNB1) as a strong susceptibility gene for schizophrenia spectrum disorders in humans.
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Affiliation(s)
- Marjaana A. Peltola
- Neuroscience Center, University of Helsinki, Helsinki, Finland;,*To whom correspondence should be addressed; Neuroscience Center, PO Box 56 (Viikinkaari 4), FI-00014 University of Helsinki, Helsinki, Finland; tel: +358-2941-57649, fax: +358-2941-57620, e-mail:
| | | | - Johanna Liuhanen
- Public Health Genomics Unit, National Institute for Health and Welfare, Helsinki, Finland
| | - Vootele Võikar
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Petteri Piepponen
- Division of Pharmacology and Toxicology, University of Helsinki, Helsinki, Finland
| | - Tero Hiekkalinna
- Public Health Genomics Unit, National Institute for Health and Welfare, Helsinki, Finland;,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Tomi Taira
- Neuroscience Center, University of Helsinki, Helsinki, Finland;,Department of Biosciences, University of Helsinki, Helsinki, Finland;,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Sari E. Lauri
- Neuroscience Center, University of Helsinki, Helsinki, Finland;,Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Jaana Suvisaari
- Department of Mental Health and Substance Abuse Services, National Institute for Health and Welfare, Helsinki, Finland
| | | | - Tiina Paunio
- Public Health Genomics Unit, National Institute for Health and Welfare, Helsinki, Finland;,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland;,Department of Psychiatry, Institute of Clinical Medicine, University of Helsinki, Helsinki, Finland
| | - Heikki Rauvala
- Neuroscience Center, University of Helsinki, Helsinki, Finland
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Zhao X, Kuja-Panula J, Sundvik M, Chen YC, Aho V, Peltola MA, Porkka-Heiskanen T, Panula P, Rauvala H. Amigo adhesion protein regulates development of neural circuits in zebrafish brain. J Biol Chem 2014; 289:19958-75. [PMID: 24904058 DOI: 10.1074/jbc.m113.545582] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Amigo protein family consists of three transmembrane proteins characterized by six leucine-rich repeat domains and one immunoglobulin-like domain in their extracellular moieties. Previous in vitro studies have suggested a role as homophilic adhesion molecules in brain neurons, but the in vivo functions remain unknown. Here we have cloned all three zebrafish amigos and show that amigo1 is the predominant family member expressed during nervous system development in zebrafish. Knockdown of amigo1 expression using morpholino oligonucleotides impairs the formation of fasciculated tracts in early fiber scaffolds of brain. A similar defect in fiber tract development is caused by mRNA-mediated expression of the Amigo1 ectodomain that inhibits adhesion mediated by the full-length protein. Analysis of differentiated neural circuits reveals defects in the catecholaminergic system. At the behavioral level, the disturbed formation of neural circuitry is reflected in enhanced locomotor activity and in the inability of the larvae to perform normal escape responses. We suggest that Amigo1 is essential for the development of neural circuits of zebrafish, where its mechanism involves homophilic interactions within the developing fiber tracts and regulation of the Kv2.1 potassium channel to form functional neural circuitry that controls locomotion.
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Affiliation(s)
| | | | - Maria Sundvik
- From the Neuroscience Center, Institute of Biomedicine/Anatomy, and
| | - Yu-Chia Chen
- From the Neuroscience Center, Institute of Biomedicine/Anatomy, and
| | - Vilma Aho
- Institute of Biomedicine/Physiology, University of Helsinki, Helsinki FIN-00014, Finland
| | | | - Tarja Porkka-Heiskanen
- Institute of Biomedicine/Physiology, University of Helsinki, Helsinki FIN-00014, Finland
| | - Pertti Panula
- From the Neuroscience Center, Institute of Biomedicine/Anatomy, and
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Peltola MA, Kuja-Panula J, Lauri SE, Taira T, Rauvala H. AMIGO is an auxiliary subunit of the Kv2.1 potassium channel. EMBO Rep 2011; 12:1293-9. [PMID: 22056818 DOI: 10.1038/embor.2011.204] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 09/21/2011] [Accepted: 09/22/2011] [Indexed: 11/09/2022] Open
Abstract
Kv2.1 is a potassium channel α-subunit abundantly expressed throughout the brain. It is a main component of delayed rectifier current (I(K)) in several neuronal types and a regulator of excitability during high-frequency firing. Here we identify AMIGO (amphoterin-induced gene and ORF), a neuronal adhesion protein with leucine-rich repeat and immunoglobin domains, as an integral part of the Kv2.1 channel complex. AMIGO shows extensive spatial and temporal colocalization and association with Kv2.1 in the mouse brain. The colocalization of AMIGO and Kv2.1 is retained even during stimulus-induced changes in Kv2.1 localization. AMIGO increases Kv2.1 conductance in a voltage-dependent manner in HEK cells. Accordingly, inhibition of endogenous AMIGO suppresses neuronal I(K) at negative membrane voltages. In conclusion, our data indicate AMIGO as a function-modulating auxiliary subunit for Kv2.1 and thus provide new insights into regulation of neuronal excitability.
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Affiliation(s)
- Marjaana A Peltola
- Neuroscience Center, University of Helsinki, PO Box 56, Helsinki FI-00014, Finland.
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Liimatainen SP, Raitanen JA, Ylinen AM, Peltola MA, Peltola JT. The benefit of active drug trials is dependent on aetiology in refractory focal epilepsy. J Neurol Neurosurg Psychiatry 2008; 79:808-12. [PMID: 17991701 DOI: 10.1136/jnnp.2007.132811] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Earlier studies have shown that aetiology makes a difference in the outcome of epilepsy, but there is a paucity of follow-up studies to evaluate the possibilities of achieving seizure freedom in initially refractory epilepsy. METHODS We evaluated the cause of epilepsy based on high-resolution brain MRI and patient history in 119 consecutive thoroughly examined adult patients with refractory focal epilepsy followed up in our centre. We also evaluated the influence of aetiology and duration of epilepsy in this patient cohort on the chances of achieving 12-month remission in a 2-year follow-up. RESULTS The major finding was that a substantial group of patients achieved remission; 30 (25%) initially refractory patients achieved at least 12 months remission during follow-up. A total of 40.0% of the patients with cryptogenic aetiology had achieved 12-month remission compared with the 16.2% patients with symptomatic aetiologies (age-adjusted OR 3.74, 95% CI 1.54 to 9.07, p = 0.004). Aetiologies often considered for surgical treatment (hippocampal sclerosis, cortical dysplasia, vascular malformation, tumour and dual pathology) carried an almost six-fold risk of persistent seizures compared with cryptogenic epilepsy (age-adjusted OR 5.85, 95% CI 2.00 to 17.11, p = 0.001). CONCLUSIONS Patients with vascular malformation and dual pathology as aetiology were most refractory, none being in remission for 12 months. There were also patients achieving 12-month remission after a long period of active epilepsy. These results encourage physicians to continue with new drug trials, especially on patients with no possibilities of epilepsy surgery, as well as on those still having seizures after epilepsy surgery.
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Affiliation(s)
- S P Liimatainen
- Neurosciences and Rehabilitation, Tampere University Hospital, PO Box 2000, 33521 Tampere, Finland.
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