1
|
Dwivedi D, Bhalla US. Physiology and Therapeutic Potential of SK, H, and M Medium AfterHyperPolarization Ion Channels. Front Mol Neurosci 2021; 14:658435. [PMID: 34149352 PMCID: PMC8209339 DOI: 10.3389/fnmol.2021.658435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/13/2021] [Indexed: 12/19/2022] Open
Abstract
SK, HCN, and M channels are medium afterhyperpolarization (mAHP)-mediating ion channels. The three channels co-express in various brain regions, and their collective action strongly influences cellular excitability. However, significant diversity exists in the expression of channel isoforms in distinct brain regions and various subcellular compartments, which contributes to an equally diverse set of specific neuronal functions. The current review emphasizes the collective behavior of the three classes of mAHP channels and discusses how these channels function together although they play specialized roles. We discuss the biophysical properties of these channels, signaling pathways that influence the activity of the three mAHP channels, various chemical modulators that alter channel activity and their therapeutic potential in treating various neurological anomalies. Additionally, we discuss the role of mAHP channels in the pathophysiology of various neurological diseases and how their modulation can alleviate some of the symptoms.
Collapse
Affiliation(s)
- Deepanjali Dwivedi
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India.,Department of Neurobiology, Harvard Medical School, Boston, MA, United States.,Stanley Center at the Broad, Cambridge, MA, United States
| | - Upinder S Bhalla
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bengaluru, India
| |
Collapse
|
2
|
Rua C, Guéguinou M, Soubai I, Viel E, Potier-Cartereau M, Chantome A, Barbe C, Bougnoux P, Barin-Le Guellec C, Vandier C. SK3 Gene Polymorphism Is Associated with Taxane Neurotoxicity and Cell Calcium Homeostasis. Clin Cancer Res 2018; 24:5313-5320. [PMID: 30037821 DOI: 10.1158/1078-0432.ccr-18-0870] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 06/13/2018] [Accepted: 07/17/2018] [Indexed: 11/16/2022]
Abstract
Purpose: Taxane-induced peripheral neuropathy is a common side effect induced by anticancer agents, and no drug capable of preventing its occurrence or ameliorating its long-term course has been identified. The physiology of taxane neuropathy is not clear, and diverse mechanisms have been suggested, with ion channels regulating Ca2+ homeostasis appearing good candidates. The calcium-activated potassium channel SK3 is encoded by the KCNN3 gene, which is characterized by a length polymorphism due to variable number of CAG repeats.Experimental Design: To study the influence of the polymorphism of CAG motif repeat of KCNN3 on the development of taxane-induced neuropathy, we evaluated 176 patients treated with taxanes for breast cancer. In parallel, we measured Ca2+ entry using Fura2-AM dye in HEK cells expressing short versus long CAG alleles of KCNN3 Results: In the current study, we report that in the presence of docetaxel, Ca2+ entry was significantly increased in cells expressing short versus long CAG alleles of SK3 and that a SK3-lipid blocker inhibits this effect. We found that patients carrying a short KCNN3 allele exhibited significantly increased incidence of taxane neuropathy compared with those carrying longer alleles.Conclusions: The clinical implication of these findings is that KCNN3 polymorphism may increase patient susceptibility to taxane neurotoxicity and that the use of SK3 blockers during taxanes' administration may represent an interesting approach for the prevention of this neurotoxicity. Clin Cancer Res; 24(21); 5313-20. ©2018 AACR.
Collapse
Affiliation(s)
- Carina Rua
- Université de Tours, Inserm, N2C UMR1069, Tours, France.,CHRU Bretonneau, Tours, France.,Ion channels and Cancer Network of Canceropole Grand Ouest (IC-CGO), Nantes, France
| | - Maxime Guéguinou
- Université de Tours, Inserm, N2C UMR1069, Tours, France.,Ion channels and Cancer Network of Canceropole Grand Ouest (IC-CGO), Nantes, France
| | - Imane Soubai
- CHRU Bretonneau, Tours, France.,Université de Tours, Faculté de Pharmacie, Tours, France
| | | | - Marie Potier-Cartereau
- Université de Tours, Inserm, N2C UMR1069, Tours, France.,Ion channels and Cancer Network of Canceropole Grand Ouest (IC-CGO), Nantes, France.,Université de Tours, Faculté de Sciences et Techniques, Tours, France
| | - Aurélie Chantome
- Université de Tours, Inserm, N2C UMR1069, Tours, France.,Ion channels and Cancer Network of Canceropole Grand Ouest (IC-CGO), Nantes, France
| | | | - Philippe Bougnoux
- Université de Tours, Inserm, N2C UMR1069, Tours, France.,CHRU Bretonneau, Tours, France.,Ion channels and Cancer Network of Canceropole Grand Ouest (IC-CGO), Nantes, France.,Université de Tours, Faculté de Médecine, Tours, France
| | - Chantal Barin-Le Guellec
- Université de Tours, Faculté de Médecine, Tours, France.,Université de Limoges, Inserm, UMR1248, Limoges, France
| | - Christophe Vandier
- Université de Tours, Inserm, N2C UMR1069, Tours, France. .,Ion channels and Cancer Network of Canceropole Grand Ouest (IC-CGO), Nantes, France.,Université de Tours, Faculté de Sciences et Techniques, Tours, France
| |
Collapse
|
3
|
Aromolaran KA, Goldstein PA. Ion channels and neuronal hyperexcitability in chemotherapy-induced peripheral neuropathy; cause and effect? Mol Pain 2017; 13:1744806917714693. [PMID: 28580836 PMCID: PMC5480635 DOI: 10.1177/1744806917714693] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 05/12/2017] [Accepted: 05/16/2017] [Indexed: 12/18/2022] Open
Abstract
Abstract Cancer is the second leading cause of death worldwide and is a major global health burden. Significant improvements in survival have been achieved, due in part to advances in adjuvant antineoplastic chemotherapy. The most commonly used antineoplastics belong to the taxane, platinum, and vinca alkaloid families. While beneficial, these agents are frequently accompanied by severe side effects, including chemotherapy-induced peripheral neuropathy (CPIN). While CPIN affects both motor and sensory systems, the majority of symptoms are sensory, with pain, tingling, and numbness being the predominant complaints. CPIN not only decreases the quality of life of cancer survivors but also can lead to discontinuation of treatment, thereby adversely affecting survival. Consequently, minimizing the incidence or severity of CPIN is highly desirable, but strategies to prevent and/or treat CIPN have proven elusive. One difficulty in achieving this goal arises from the fact that the molecular and cellular mechanisms that produce CPIN are not fully known; however, one common mechanism appears to be changes in ion channel expression in primary afferent sensory neurons. The processes that underlie chemotherapy-induced changes in ion channel expression and function are poorly understood. Not all antineoplastic agents directly affect ion channel function, suggesting additional pathways may contribute to the development of CPIN Indeed, there are indications that these drugs may mediate their effects through cellular signaling pathways including second messengers and inflammatory cytokines. Here, we focus on ion channelopathies as causal mechanisms for CPIN and review the data from both pre-clinical animal models and from human studies with the aim of facilitating the development of appropriate strategies to prevent and/or treat CPIN.
Collapse
Affiliation(s)
- Kelly A Aromolaran
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Peter A Goldstein
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
- Department of Medicine, Weill Cornell Medical College, New York, NY, USA
| |
Collapse
|
4
|
El-Hassar L, Simen AA, Duque A, Patel KD, Kaczmarek LK, Arnsten AF, Yeckel MF. Disrupted in schizophrenia 1 modulates medial prefrontal cortex pyramidal neuron activity through cAMP regulation of transient receptor potential C and small-conductance K+ channels. Biol Psychiatry 2014; 76:476-85. [PMID: 24560582 PMCID: PMC4104266 DOI: 10.1016/j.biopsych.2013.12.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 12/22/2013] [Accepted: 12/30/2013] [Indexed: 02/06/2023]
Abstract
BACKGROUND Disrupted in schizophrenia 1 (DISC1) is a protein implicated in schizophrenia, bipolar disorder, major depressive disorder, and autism. To date, most of research examining DISC1 function has focused on its role in neurodevelopment, despite its presence throughout life. DISC1 also regulates cyclic adenosine monophosphate (cAMP) signaling by increasing type 4 phosphodiesterase catabolism of cAMP when cAMP concentrations are high. In this study, we tested the hypothesis that DISC1, through its regulation of cAMP, modulates I-SK and I-TRPC channel-mediated ionic currents that we have shown previously to regulate the activity of mature prefrontal cortical pyramidal neurons. METHODS We used patch-clamp recordings in prefrontal cortical slices from adult rats in which DISC1 function was reduced in vivo by short hairpin RNA viral knockdown or in vitro by dialysis of DISC1 antibodies. RESULTS We found that DISC1 disruption resulted in an increase of metabotropic glutamate receptor-induced intracellular calcium (Ca2+) waves, small-conductance K+ (SK)-mediated hyperpolarization and a decrease of transient receptor potential C (TRPC)-mediated sustained depolarization. Consistent with a role for DISC1 in regulation of cAMP signaling, forskolin-induced cAMP production also increased intracellular Ca2+ waves, I-SK and decreased I-TRPC. Lastly, inhibiting cAMP generation with guanfacine, an α2A-noradrenergic agonist, normalized the function of SK and TRPC channels. CONCLUSIONS Based on our findings, we propose that diminished DISC1 function, such as occurs in some mental disorders, can lead to the disruption of normal patterns of prefrontal cortex activity through the loss of cAMP regulation of metabotropic glutamate receptor-mediated intracellular Ca2+ waves, SK and TRPC channel activity.
Collapse
Affiliation(s)
- Lynda El-Hassar
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut.
| | - Arthur A. Simen
- Department of Psychiatry, Yale University School of Medicine
| | - Alvaro Duque
- Department of Neurobiology, Yale University School of Medicine
| | - Kiran D. Patel
- Department of Psychiatry, Yale University School of Medicine
| | | | - Amy F.T. Arnsten
- Department of Neurobiology, Yale University School of Medicine,The Kavli Institute for Neuroscience, Yale University School of Medicine
| | - Mark F. Yeckel
- Department of Neurobiology, Yale University School of Medicine,The Kavli Institute for Neuroscience, Yale University School of Medicine
| |
Collapse
|
5
|
Judy JT, Zandi PP. A review of potassium channels in bipolar disorder. Front Genet 2013; 4:105. [PMID: 23781230 PMCID: PMC3678088 DOI: 10.3389/fgene.2013.00105] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/22/2013] [Indexed: 12/11/2022] Open
Abstract
Although bipolar disorder (BP) is one of the most heritable psychiatric conditions, susceptibility genes for the disorder have yet to be conclusively identified. It is likely that variants in multiple genes across multiple pathways contribute to the genotype–phenotype relationship in the affected population. Recent evidence from genome-wide association studies implicates an entire class of genes related to the structure and regulation of ion channels, suggesting that the etiology of BP may arise from channelopathies. In this review, we examine the evidence for this hypothesis, with a focus on the potential role of voltage-gated potassium channels. We consider evidence from genetic and expression studies, and discuss the potential underlying biology. We consider animal models and treatment implications of the involvement of potassium ion channelopathy in BP. Finally, we explore intriguing parallels between BP and epilepsy, the signature channelopathy of the central nervous system.
Collapse
Affiliation(s)
- Jennifer T Judy
- Department of Psychiatry, Johns Hopkins School of Medicine Baltimore, MD, USA
| | | |
Collapse
|
6
|
Ion channels and schizophrenia: a gene set-based analytic approach to GWAS data for biological hypothesis testing. Hum Genet 2011; 131:373-91. [PMID: 21866342 DOI: 10.1007/s00439-011-1082-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Accepted: 08/08/2011] [Indexed: 01/11/2023]
Abstract
Schizophrenia is a complex genetic disorder. Gene set-based analytic (GSA) methods have been widely applied for exploratory analyses of large, high-throughput datasets, but less commonly employed for biological hypothesis testing. Our primary hypothesis is that variation in ion channel genes contribute to the genetic susceptibility to schizophrenia. We applied Exploratory Visual Analysis (EVA), one GSA application, to analyze European-American (EA) and African-American (AA) schizophrenia genome-wide association study datasets for statistical enrichment of ion channel gene sets, comparing GSA results derived under three SNP-to-gene mapping strategies: (1) GENIC; (2) 500-Kb; (3) 2.5-Mb and three complimentary SNP-to-gene statistical reduction methods: (1) minimum p value (pMIN); (2) a novel method, proportion of SNPs per Gene with p values below a pre-defined α-threshold (PROP); and (3) the truncated product method (TPM). In the EA analyses, ion channel gene set(s) were enriched under all mapping and statistical approaches. In the AA analysis, ion channel gene set(s) were significantly enriched under pMIN for all mapping strategies and under PROP for broader mapping strategies. Less extensive enrichment in the AA sample may reflect true ethnic differences in susceptibility, sampling or case ascertainment differences, or higher dimensionality relative to sample size of the AA data. More consistent findings under broader mapping strategies may reflect enhanced power due to increased SNP inclusion, enhanced capture of effects over extended haplotypes or significant contributions from regulatory regions. While extensive pMIN findings may reflect gene size bias, the extent and significance of PROP and TPM findings suggest that common variation at ion channel genes may capture some of the heritability of schizophrenia.
Collapse
|
7
|
Polymorphism of CAG motif of SK3 gene is associated with acute oxaliplatin neurotoxicity. Cancer Chemother Pharmacol 2010; 67:1179-87. [DOI: 10.1007/s00280-010-1466-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Accepted: 09/09/2010] [Indexed: 12/27/2022]
|
8
|
Ivković M, Ranković V, Tarasjev A, Orolicki S, Damjanović A, Paunović VR, Romac S. SCHIZOPHRENIA AND POLYMORPHIC CAG REPEATS ARRAY OF CALCIUM-ACTIVATED POTASSIUM CHANNEL (KCNN3) GENE IN SERBIAN POPULATION. Int J Neurosci 2009; 116:157-64. [PMID: 16393881 DOI: 10.1080/00207450341514] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
KCNN3 might be a candidate gene for schizophrenia. The KCNN3 cDNA sequence contains two stretches of CAG trinucleotide repeats encoding two separate polyglutamine segments near the N-terminus of this channel protein. The second CAG repeat is highly polymorphic in the Caucasian population from both Europe and United States. The authors carried out a study to compare the allelic frequency distribution of the CAG repeat in KCNN3 gene in 55 Serbian schizophrenic patients and 46 controls. The data indicate a significant association between longer CAG repeats in second polymorphic KCNN3 region and schizophrenia in the Serbian population.
Collapse
Affiliation(s)
- M Ivković
- Institute for Psychiatry, Clinical Center of Serbia, Belgrade, Serbia and Montenegro
| | | | | | | | | | | | | |
Collapse
|
9
|
Pathways-based analyses of whole-genome association study data in bipolar disorder reveal genes mediating ion channel activity and synaptic neurotransmission. Hum Genet 2008; 125:63-79. [PMID: 19052778 DOI: 10.1007/s00439-008-0600-y] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 11/21/2008] [Indexed: 01/10/2023]
Abstract
Despite known heritability, the complex genetic architecture of bipolar disorder (likely including trait, locus and allelic heterogeneity, as well as genetic interactions) has confounded genetic discovery for many years. Even modern day whole genome association studies (WGAS) using over half a million common SNPs have implicated only a handful of genes at the genomewide level. Temporally coincident with this series of WGAS, a host of pathways-based analyses (PBAs) have emerged as novel computational approaches in the examination of large-scale datasets, but thus far rarely have been applied to WGAS data in psychiatric disorders. Here, we report a series of PBAs conducted using exploratory visual analysis, an analytic and visualization software tool for examining genomic data, to examine results from the National Institutes of Mental Health and Wellcome-Trust Case Control Consortium WGAS in bipolar disorder. Consistent with a host of prior linkage findings, some candidate gene association studies, and recent WGAS, our strongest findings suggest involvement of ion channel structural and regulatory genes, including voltage-gated ion channels and the broader ion channel group that comprises both voltage- and ligand-gated channels. Moreover, we found only modest overlap in the particular genes driving the significance of these gene sets across the analyses. This observation strongly suggests that variation in ion channel genes, as a class of genes, may contribute to the susceptibility of bipolar disorder and that heterogeneity may figure prominently in the genetic architecture of this susceptibility.
Collapse
|
10
|
Molecular and cellular basis of small--and intermediate-conductance, calcium-activated potassium channel function in the brain. Cell Mol Life Sci 2008; 65:3196-217. [PMID: 18597044 PMCID: PMC2798969 DOI: 10.1007/s00018-008-8216-x] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Small conductance calcium-activated potassium (SK or KCa2) channels link intracellular calcium transients to membrane potential changes. SK channel subtypes present different pharmacology and distribution in the nervous system. The selective blocker apamin, SK enhancers and mice lacking specific SK channel subunits have revealed multifaceted functions of these channels in neurons, glia and cerebral blood vessels. SK channels regulate neuronal firing by contributing to the afterhyperpolarization following action potentials and mediating IAHP, and partake in a calcium-mediated feedback loop with NMDA receptors, controlling the threshold for induction of hippocampal long-term potentiation. The function of distinct SK channel subtypes in different neurons often results from their specific coupling to different calcium sources. The prominent role of SK channels in the modulation of excitability and synaptic function of limbic, dopaminergic and cerebellar neurons hints at their possible involvement in neuronal dysfunction, either as part of the causal mechanism or as potential therapeutic targets.
Collapse
|
11
|
Chen QY, Chen Q, Feng GY, Lindpaintner K, Wang LJ, Chen ZX, Gao ZS, Tang JS, Huang G, He L. Case-control association study of Disrupted-in-Schizophrenia-1 (DISC1) gene and schizophrenia in the Chinese population. J Psychiatr Res 2007; 41:428-34. [PMID: 16524593 DOI: 10.1016/j.jpsychires.2006.01.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 01/04/2006] [Accepted: 01/10/2006] [Indexed: 11/16/2022]
Abstract
Disrupted-in-Schizophrenia-1 (DISC1) has first been identified as a candidate gene for schizophrenia through study of a Scottish family with a balanced (1; 11) (q42.1; q14.3) translocation. Lots of linkage and association studies supported DISC1 as a risk factor for schizophrenia. In this study, we genotyped three SNPs in DISC1 using a set of Han Chinese samples of 560 schizophrenics and 576 controls. No positive association was detected in the whole samples but analysis of allele frequencies in female samples showed weak association between SNP rs2295959 and the disease (chi(2)=6.188, P=0.0135, OR=0.728, 95% CI=0.567-0.935). Our results provide further evidence for sex difference for the effect of the gene on the aetiology of schizophrenia. Our findings also would encourage further studies, particularly family-based association studies with larger samples, to analyze the association between DISC1 and schizophrenia.
Collapse
Affiliation(s)
- Qing-Ying Chen
- Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 319 Yue Yang Road, Shanghai 200031, PR China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Gargus JJ. Ion channel functional candidate genes in multigenic neuropsychiatric disease. Biol Psychiatry 2006; 60:177-85. [PMID: 16497276 DOI: 10.1016/j.biopsych.2005.12.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 11/15/2005] [Accepted: 12/15/2005] [Indexed: 10/25/2022]
Abstract
Scores of monogenic Mendelian ion channel diseases serve to anchor the pathophysiology of the channelopathies, but there are also now clear examples of environmental, pharmacogenetic, and acquired channelopathy mechanisms. The cardinal feature of heritable ion channel disease is a periodic disturbance of rhythmic function in constitutionally hyperexcitable tissue. While the complexity of neuroanatomy obscures functional analysis of mutations causing monogenic seizure, ataxia, or migraine syndromes, extrapolation from the cardiac (Long QT [LQT]) and muscle (Periodic Paralysis) channelopathy syndromes provides a simplified predictive framework of molecular pathology: electrically stabilizing potassium ion (K(+)) and chloride ion (Cl(-)) channels, likely having lesions that diminish their current, and excitatory Na(+) channels, likely having gain-of-function lesions. The voltage-gated calcium channel gene family that contains CACNA1C, the newest LQT locus, causing Timothy Syndrome with a phenotype including autism, has proven to be particularly informative for its members' ability to tie the various central nervous system (CNS) phenotypes together in an interpretable fashion, now including direct extension to the classically multigenic neuropsychiatric phenotypes. Features of a promising ion channel candidate gene arise from its broad locus, gene family, nature of alleles, physiology and pharmacology, tissue expression profile, and phenotype in model organisms. KCNN3 is explored as a paradigm to consider.
Collapse
Affiliation(s)
- J Jay Gargus
- Department of Physiology, Section of Human Genetics, University of California, Irvine, California 92697-4034, USA.
| |
Collapse
|
13
|
Curtain R, Sundholm J, Lea R, Ovcaric M, MacMillan J, Griffiths L. Association analysis of a highly polymorphic CAG Repeat in the human potassium channel gene KCNN3 and migraine susceptibility. BMC MEDICAL GENETICS 2005; 6:32. [PMID: 16162291 PMCID: PMC1236929 DOI: 10.1186/1471-2350-6-32] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 09/14/2005] [Indexed: 11/10/2022]
Abstract
BACKGROUND Migraine is a polygenic multifactorial disease, possessing environmental and genetic causative factors with multiple involved genes. Mutations in various ion channel genes are responsible for a number of neurological disorders. KCNN3 is a neuronal small conductance calcium-activated potassium channel gene that contains two polyglutamine tracts, encoded by polymorphic CAG repeats in the gene. This gene plays a critical role in determining the firing pattern of neurons and acts to regulate intracellular calcium channels. METHODS The present association study tested whether length variations in the second (more 3') polymorphic CAG repeat in exon 1 of the KCNN3 gene, are involved in susceptibility to migraine with and without aura (MA and MO). In total 423 DNA samples from unrelated individuals, of which 202 consisted of migraine patients and 221 non-migraine controls, were genotyped and analysed using a fluorescence labelled primer set on an ABI310 Genetic Analyzer. Allele frequencies were calculated from observed genotype counts for the KCNN3 polymorphism. Analysis was performed using standard contingency table analysis, incorporating the chi-squared test of independence and CLUMP analysis. RESULTS Overall, there was no convincing evidence that KCNN3 CAG lengths differ between Caucasian migraineurs and controls, with no significant difference in the allelic length distribution of CAG repeats between the population groups (P = 0.090). Also the MA and MO subtypes did not differ significantly between control allelic distributions (P > 0.05). The prevalence of the long CAG repeat (>19 repeats) did not reach statistical significance in migraineurs (P = 0.15), nor was there a significant difference between the MA and MO subgroups observed compared to controls (P = 0.46 and P = 0.09, respectively), or between MA vs MO (P = 0.40). CONCLUSION This association study provides no evidence that length variations of the second polyglutamine array in the N-terminus of the KCNN3 channel exert an effect in the pathogenesis of migraine.
Collapse
Affiliation(s)
- Robert Curtain
- Genomics Research Centre, School of Health Science, Griffith University, Gold Coast, Queensland, Australia
| | - James Sundholm
- Genomics Research Centre, School of Health Science, Griffith University, Gold Coast, Queensland, Australia
| | - Rod Lea
- Genomics Research Centre, School of Health Science, Griffith University, Gold Coast, Queensland, Australia
- Institute of Environmental Science and Research, Wellington, New Zealand
| | - Mick Ovcaric
- Genomics Research Centre, School of Health Science, Griffith University, Gold Coast, Queensland, Australia
| | - John MacMillan
- Queensland Clinical Genetics Service, Royal Children's Hospital Health Service District, Brisbane, Queensland, Australia
| | - Lyn Griffiths
- Genomics Research Centre, School of Health Science, Griffith University, Gold Coast, Queensland, Australia
| |
Collapse
|
14
|
Myslobodsky M. Phobic memory and somatic vulnerabilities in anorexia nervosa: a necessary unity? Ann Gen Psychiatry 2005; 4:15. [PMID: 16144551 PMCID: PMC1260012 DOI: 10.1186/1744-859x-4-15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2005] [Accepted: 09/06/2005] [Indexed: 11/10/2022] Open
Abstract
Anorexia nervosa is a clinically significant illness that may be associated with permanent medical complications involving almost every organ system. The paper raises a question whether some of them are associated with premorbid vulnerability such as subcellular ion channel abnormalities ('channelopathy') that determines the clinical expression of the bodily response to self-imposed malnutrition. Aberrant channels emerge as a tempting, if rather speculative alternative to the notion of cognitively-driven neurotransmitter modulation deficit in anorexia nervosa. The concept of channelopathies is in keeping with some characteristics of anorexia nervosa, such as a genetically-based predisposition to hypophagia, early onset, cardiac abnormalities, an appetite-enhancing efficacy of some antiepileptic drugs, and others. The purpose of this article is to stimulate further basic research of ion channel biophysics in relation to restrictive anorexia.
Collapse
|
15
|
Mössner R, Weichselbaum A, Marziniak M, Freitag CM, Lesch KP, Sommer C, Meyer J. A Highly Polymorphic Poly-Glutamine Stretch in the Potassium Channel KCNN3 in Migraine. Headache 2005; 45:132-6. [PMID: 15705118 DOI: 10.1111/j.1526-4610.2005.05027.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The present study is designed to further elucidate the molecular genetic basis of migraine with and without aura. BACKGROUND Migraine is a common disease of as yet unknown etiology. Interest in ion channels in migraine has been spurred by molecular genetic findings in familial hemiplegic migraine, since familial hemiplegic migraine type 1 is caused by mutations in the calcium channel gene CACNA1A. METHODS Given this role of ion channels in migraine, we assessed the potassium channel KCNN3 as a candidate gene for common migraine. We analyzed the highly polymorphic repeat region coding for a poly-glutamine stretch, which constitutes part of the cytoplasmic tail of the channel protein. RESULTS We found an excess of the allele coding for 15 poly-glutamines in migraine patients. CONCLUSIONS The potassium channel KCNN3 may thus be of pathophysiological importance in migraine with and without aura.
Collapse
|
16
|
Glatt SJ, Faraone SV, Tsuang MT. CAG-repeat length in exon 1 of KCNN3 does not influence risk for schizophrenia or bipolar disorder: a meta-analysis of association studies. Am J Med Genet B Neuropsychiatr Genet 2003; 121B:14-20. [PMID: 12898569 DOI: 10.1002/ajmg.b.20048] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Schizophrenia and bipolar disorder both show some evidence for genetic anticipation. In addition, significant expansion of anonymous CAG repeats throughout the genome has been detected in both of these disorders. The gene KCNN3, which codes for a small/intermediate conductance, calcium-regulated potassium channel, contains a highly polymorphic CAG-repeat array in exon 1. Initial evidence for association of both schizophrenia and bipolar disorder with increased CAG-repeat length of KCNN3 has not been consistently replicated. In the present study, we performed several meta-analyses to evaluate the pooled evidence for association with CAG-repeat length of KCNN3 derived from case-control and family-based studies of both disorders. Each group of studies was analyzed under two models, including a test for direct association with repeat length, and a test for association with dichotomized repeat-length groups. No evidence for a linear relationship between disease risk and repeat length was observed, as all pooled odds ratios approximated 1.0. Results of dichotomized allele-group analyses were more variable, especially for schizophrenia, where case-control studies found a significant association with longer repeats but family-based studies implicated shorter alleles. The results of these meta-analyses demonstrate that the risks for both schizophrenia and bipolar disorder are largely, if not entirely, independent of CAG-repeat length in exon 1 of KCNN3. This study cannot exclude the possibility that some aspect of this polymorphism, such as repeat-length disparity in heterozygotes, influences risk for these disorders. Further, it remains unknown if this polymorphism, or one in linkage disequilibrium with it, contributes to some distinct feature of the disorder, such as symptom severity or anticipation.
Collapse
Affiliation(s)
- Stephen J Glatt
- Department of Psychiatry, Harvard Medical School at Massachusetts Mental Health Center, Boston, Massachusetts 02115, USA
| | | | | |
Collapse
|
17
|
Tomita H, Shakkottai VG, Gutman GA, Sun G, Bunney WE, Cahalan MD, Chandy KG, Gargus JJ. Novel truncated isoform of SK3 potassium channel is a potent dominant-negative regulator of SK currents: implications in schizophrenia. Mol Psychiatry 2003; 8:524-35, 460. [PMID: 12808432 DOI: 10.1038/sj.mp.4001271] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The small-conductance calcium-activated K(+) channel SK3 (SKCa3/KCNN3) regulates electrical excitability and neurotransmitter release in monoaminergic neurons, and has been implicated in schizophrenia, ataxia and anorexia nervosa. We have identified a novel SK3 transcript, SK3-1B that utilizes an alternative first exon (exon 1B), but is otherwise identical to SK3. SK3-1B, mRNA is widely distributed in human tissues and is present at 20-60% of SK3 in the brain. The SK3-1B protein lacks the N-terminus and first transmembrane segment, and begins eight residues upstream of the second transmembrane segment. When expressed alone, SK3-1B did not produce functional channels, but selectively suppressed endogenous SK3 currents in the pheochromocytoma cell line, PC12, in a dominant-negative fashion. This dominant inhibitory effect extended to other members of the SK subfamily, but not to voltage-gated K(+) channels, and appears to be due to intracellular trapping of endogenous SK channels. The effect of SK3-1B expression is very similar to that produced by expression of the rare SK3 truncation allele, SK3-Delta, found in a patient with schizophrenia. Regulation of SK3 and SK3-1B levels may provide a potent mechanism to titrate neuronal firing rates and neurotransmitter release in monoaminergic neurons, and alterations in the relative abundance of these proteins could contribute to abnormal neuronal excitability, and to the pathogenesis of schizophrenia.
Collapse
Affiliation(s)
- H Tomita
- Department of Physiology and Biophysics, University of California, Irvine, CA 92697-4034, USA
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Hwu HG, Liu CM, Fann CSJ, Ou-Yang WC, Lee SFC. Linkage of schizophrenia with chromosome 1q loci in Taiwanese families. Mol Psychiatry 2003; 8:445-52. [PMID: 12740602 DOI: 10.1038/sj.mp.4001235] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
A positive linkage of schizophrenia with chromosome 1q loci has been reported in Caucasian patients. This study was designed to evaluate the linkage of schizophrenia with markers of the 1q22-44 region in 52 Taiwanese families with at least two affected siblings. In the region 1q22-31 (17.8 cM), marker D1S1679 had a maximal proportion (0.57, P=0.03) of shared identity by descent (IBD) under a narrow phenotype (DSM-IV schizophrenia only). In the region 1q42-44 (26.8 cM), the marker D1S251, located near the breakpoint of a balanced translocation t (1;11) (q42.1;q14.3) segregated with schizophrenia, and also near the neurodevelopment-related 'Disrupted in Schizophrenia 1' gene, had a maximum NPL score of 1.73 (P=0.03) under the narrow phenotype model and 2.18 (P=0.01) under the broad phenotype model comprised of schizophrenia, schizoaffective disorder, and other nonaffective psychotic disorders as defined by DSM-IV criteria. The marker D1S2836 also had a maximal proportion (0.57, P=0.05) of shared IBD under the broad model. These findings may provide guidance for positional cloning studies on candidate genes in the 1q22-31 and 1q41-44 regions.
Collapse
Affiliation(s)
- H-G Hwu
- Department of Psychiatry, National Taiwan University Hospital and National Taiwan University College of Medicine, National Taiwan University, Taipei, Taiwan.
| | | | | | | | | |
Collapse
|
19
|
Laurent C, Niehaus D, Bauché S, Levinson DF, Soubigou S, Pimstone S, Hayden M, Mbanga I, Emsley R, Deleuze JF, Mallet J. CAG repeat polymorphisms in KCNN3 (HSKCa3) and PPP2R2B show no association or linkage to schizophrenia. Am J Med Genet B Neuropsychiatr Genet 2003; 116B:45-50. [PMID: 12497613 DOI: 10.1002/ajmg.b.10797] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The purpose of this study was to determine whether genetic linkage or association could be observed between schizophrenia (SZ) and the CAG repeat polymorphisms within the genes KCNN3 (known previously as hSKCa3) and PPP2R2B (linked to Spino-Cerebellar Atrophy 12) in the Xhosa population in South Africa. Neither locus has been studied previously in African populations. The polymorphisms were genotyped in 589 individuals to form samples for Transmission Disequilibrium Test (TDT) analysis (176 unrelated probands, 145 with both parents and 30 with one parent genotyped), linkage analysis (49 families with 54 independent affected sib pairs [ASPs]), and case-control analyses (67 familial cases with a first-degree SZ relative, 101 sporadic cases with no affected first- or second-degree relative, and 90 control cases). No significant differences were found among familial cases, sporadic cases and controls in allele sizes (Kruskal-Wallis tests) or the numbers of alleles with sizes above and below the mean size for each polymorphism. Allele size was not correlated with age of onset (Spearman correlation). No significant evidence for association was observed using TDT analyses for all triads and separately for the familial triads. No significant evidence for linkage was observed for either locus with affected sib pair analysis using the possible triangle method or with Non-Parametric Linkage (NPL) analysis of the multiplex families. In conclusion, no significant evidence for linkage or association with SZ was observed for either polymorphism in this population.
Collapse
Affiliation(s)
- Claudine Laurent
- LGN-CNRS UMR 7091, Bâtiment CERVI, Hôpital de la Pitié-Salpêtrière, Paris, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Ritsner M, Modai I, Ziv H, Amir S, Halperin T, Weizman A, Navon R. An association of CAG repeats at the KCNN3 locus with symptom dimensions of schizophrenia. Biol Psychiatry 2002; 51:788-94. [PMID: 12007452 DOI: 10.1016/s0006-3223(01)01348-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND In 1999 Cardno et al reported that long CAG repeats in the calcium-activated potassium channel gene hSKCa3/KCNN3 are associated with higher negative symptom dimension scores in schizophrenia patients. There has been no attempt to replicate the results. In this study, we investigated whether a symptom polymorphism of schizophrenia is associated with both the CAG repeat numbers and the difference in allele sizes. METHODS We tested the association of CAG repeats with symptom models of schizophrenia in 117 unrelated Jewish patients. A multivariate analysis (MANOVA) of two models of schizophrenia with the repeat distribution and the difference in allele sizes was performed. RESULTS We found a significant positive association of the number of CAG repeats with negative syndrome, anergia, activation, and paranoid symptoms. In addition, nonparanoid schizophrenia patients who had differences in allele sizes were characterized by earlier onset of illness. CONCLUSIONS The study supports the hypothesis that the combined effect of long CAG repeats and the differences in allele sizes contribute to symptom expression of schizophrenia, particularly on the anergia-activation-paranoid axis.
Collapse
Affiliation(s)
- Michael Ritsner
- Sha'ar Menashe Mental Health Center, Mobile Post Hefer 38814, Hadera, Israel
| | | | | | | | | | | | | |
Collapse
|
21
|
Koronyo-Hamaoui M, Danziger Y, Frisch A, Stein D, Leor S, Laufer N, Carel C, Fennig S, Minoumi M, Apter A, Goldman B, Barkai G, Weizman A, Gak E. Association between anorexia nervosa and the hsKCa3 gene: a family-based and case control study. Mol Psychiatry 2002; 7:82-5. [PMID: 11803450 DOI: 10.1038/sj.mp.4000931] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2000] [Revised: 03/27/2001] [Accepted: 03/29/2001] [Indexed: 11/08/2022]
Abstract
Familial and twin studies have suggested that anorexia nervosa (AN) is a multifactorial disorder with a substantial genetic contribution. The hSKCa3 potassium channel gene, which contains polymorphic CAG repeats in the coding region and is involved in the regulation of neuronal activity, may be a candidate gene for AN because alleles with longer repeats have been found to be associated with mental disorders. Forty Israeli AN family trios were genotyped for the hSKCa3 CAG repeat polymorphism using the haplotype relative risk (HRR) method. The distribution of alleles transmitted to the patients was found to be significantly different from that of the non-transmitted parental alleles, with the longer alleles being over-represented in the patients (Wilcoxon rank test, P = 0.008). The transmission disequilibrium test (TDT) revealed that longer (>19) repeat alleles were preferentially transmitted to AN patients (McNemar's chi(2) = 10.31, P = 0.0013). These results were corroborated by comparing the distribution of alleles between patients and healthy controls (Mann-Whitney test, P = 0.005). Our study suggests that the longer repeat alleles of the hSKCa3 gene may contribute to the genetic susceptibility to AN.
Collapse
Affiliation(s)
- M Koronyo-Hamaoui
- The Danek Gertner Institute of Human Genetics, Sheba Medical Center, Tel Hashomer, Israel
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Prasad S, Semwal P, Deshpande S, Bhatia T, Nimgaonkar VL, Thelma BK. Molecular genetics of schizophrenia: past, present and future. J Biosci 2002; 27:35-52. [PMID: 11927776 DOI: 10.1007/bf02703682] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Schizophrenia is a severe neuropsychiatric disorder with a polygenic mode of inheritance which is also governed by non-genetic factors. Candidate genes identified on the basis of biochemical and pharmacological evidence are being tested for linkage and association studies. Neurotransmitters, especially dopamine and serotonin have been widely implicated in its etiology. Genome scan of all human chromosomes with closely spaced polymorphic markers is being used for linkage studies. The completion and availability of the first draft of Human Genome Sequence has provided a treasure-trove that can be utilized to gain insight into the so far inaccessible regions of the human genome. Significant technological advances for identification of single nucleo-tide polymorphisms (SNPs) and use of microarrays have further strengthened research methodologies for genetic analysis of complex traits. In this review, we summarize the evolution of schizophrenia genetics from the past to the present, current trends and future direction of research.
Collapse
Affiliation(s)
- Suman Prasad
- Department of Genetics, University of Delhi South Campus, Benito Juarez Road, New Delhi 110 021, India
| | | | | | | | | | | |
Collapse
|
23
|
Imamura A, Tsujita T, Kayashima T, Oda R, Kikuchi T, Hayashida M, Hamada A, Fujimaru K, Matsumoto S, Hashida A, Nakane Y, Okazaki Y. Lack of association between the hKCa3 gene and Japanese schizophrenia patients. Psychiatr Genet 2001; 11:227-9. [PMID: 11807415 DOI: 10.1097/00041444-200112000-00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Several researchers have suggested an association between large numbers of CAG repeats in the hKCa3 gene and schizophrenia. However, these reports remain inconclusive and require further investigation. We tried to replicate these results in 112 Japanese schizophrenia patients and 102 control subjects of highly matched age and sex by applying an allele dichotomization model. No association was found. The overall distributions of allele frequencies were not significantly different between schizophrenic patients and normal control subjects. In addition, we tested the association between the size of the CAG repeats and the scores on three dimensions (positive and negative symptoms, and disorganization), but no significant results were obtained. Our results do not support the involvement of the hKCa3 gene in schizophrenia, at least in the Japanese population.
Collapse
Affiliation(s)
- A Imamura
- Department of Neuropsychiatry, Nagasaki University School of Medicine, Nagasaki, Japan.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Goossens D, Del-Favero J, Van Broeckhoven C. Trinucleotide repeat expansions: do they contribute to bipolar disorder? Brain Res Bull 2001; 56:243-57. [PMID: 11719258 DOI: 10.1016/s0361-9230(01)00657-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
It has long been known that bipolar disorder has a true but complex genetic background. Reports on genetic anticipation in bipolar disorder opened the way to a new approach for genetic studies. Indeed, anticipation, a decreasing age at onset, and/or increasing disease severity in successive generations, were recently explained by an expansion of trinucleotide repeats in monogenic diseases like Huntington's disease and Fragile X syndrome. The involvement of trinucleotide repeat expansions in bipolar disorder received even more support when studies reported association of large CAG/CTG repeats with bipolar disorder. Even though a large number of studies have been conducted, this association is still unexplained. Here, we review the studies investigating the trinucleotide repeat expansion hypothesis in bipolar disorder. Studies on anticipation, on association of anonymous large CAG/CTG repeats and on specific trinucleotide repeats are critically analysed and discussed, showing a field with precipitate conclusions or inconclusive results. The analysis suggests that there are indications, though disputable, supporting the trinucleotide repeat expansion hypothesis in bipolar disorder, but no conclusive evidence has been hitherto provided.
Collapse
Affiliation(s)
- D Goossens
- Department of Molecular Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), University of Antwerp (UIA), Antwerpen, Belgium
| | | | | |
Collapse
|
25
|
Miller MJ, Rauer H, Tomita H, Rauer H, Gargus JJ, Gutman GA, Cahalan MD, Chandy KG. Nuclear localization and dominant-negative suppression by a mutant SKCa3 N-terminal channel fragment identified in a patient with schizophrenia. J Biol Chem 2001; 276:27753-6. [PMID: 11395478 DOI: 10.1074/jbc.c100221200] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The small conductance calcium-activated K+ channel gene SKCa3/KCNN3 maps to 1q21, a region strongly linked to schizophrenia. Recently, a 4-base pair deletion in SKCa3 was reported in a patient with schizophrenia, which truncates the protein at the end of the N-terminal cytoplasmic region (SKCa3Delta). We generated a green fluorescent protein-SKCa3 N-terminal construct (SKCa3-1/285) that is identical to SKCa3Delta except for the last two residues. Using confocal microscopy we demonstrate that SKCa3-1/285 localizes rapidly and exclusively to the nucleus of mammalian cells like several other pathogenic polyglutamine-containing proteins. This nuclear targeting is mediated in part by two polybasic sequences present at the C-terminal end of SKCa3-1/285. In contrast, full-length SKCa3, SKCa2, and IKCa1 polypeptides are all excluded from the nucleus and express as functional channels. When overexpressed in human Jurkat T cells, SKCa3-1/285 can suppress endogenous SKCa2 currents but not voltage-gated K+ currents. This dominant-negative suppression is most likely mediated through the co-assembly of SKCa3-1/285 with native subunits and the formation of non-functional tetramers. The nuclear localization of SKCa3-1/285 may alter neuronal architecture, and its ability to dominantly suppress endogenous small conductance K(Ca) currents may affect patterns of neuronal firing. Together, these two effects may play a part in the pathogenesis of schizophrenia and other neuropsychiatric disorders.
Collapse
Affiliation(s)
- M J Miller
- Department of Physiology and Biophysics, Division of Human Genetics, University of California Irvine, Irvine, California 92697-4561, USA
| | | | | | | | | | | | | | | |
Collapse
|
26
|
Bowen T, Williams N, Norton N, Spurlock G, Wittekindt OH, Morris-Rosendahl DJ, Williams H, Brzustowicz L, Hoogendoorn B, Zammit S, Jones G, Sanders RD, Jones LA, McCarthy G, Jones S, Bassett A, Cardno AG, Owen MJ, O'Donovan MC. Mutation screening of the KCNN3 gene reveals a rare frameshift mutation. Mol Psychiatry 2001; 6:259-60. [PMID: 11326292 DOI: 10.1038/sj.mp.4000128] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
27
|
Lunkes A, Trottier Y, Fagart J, Schultz P, Zeder-Lutz G, Moras D, Mandel JL. Properties of polyglutamine expansion in vitro and in a cellular model for Huntington's disease. Philos Trans R Soc Lond B Biol Sci 1999; 354:1013-9. [PMID: 10434300 PMCID: PMC1692598 DOI: 10.1098/rstb.1999.0453] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Eight neurodegenerative diseases have been shown to be caused by the expansion of a polyglutamine stretch in specific target proteins that lead to a gain in toxic property. Most of these diseases have some features in common. A pathological threshold of 35-40 glutamine residues is observed in five of the diseases. The mutated proteins (or a polyglutamine-containing subfragment) form ubiquitinated aggregates in neurons of patients or mouse models, in most cases within the nucleus. We summarize the properties of a monoclonal antibody that recognizes specifically, in a Western blot, polyglutamine stretches longer than 35 glutamine residues with an affinity that increases with polyglutamine length. This indicates that the pathological threshold observed in five diseases corresponds to a conformational change creating a pathological epitope, most probably involved in the aggregation property of the carrier protein. We also show that a fragment of a normal protein carrying 38 glutamine residues is able to aggregate into regular fibrils in vitro. Finally, we present a cellular model in which the induced expression of a mutated full-length huntingtin protein leads to the formation of nuclear inclusions that share many characteristics with those observed in patients: those inclusions are ubiquitinated and contain only an N-terminal fragment of huntingtin. This model should thus be useful in studying a processing step that is likely to be important in the pathogenicity of mutated huntingtin.
Collapse
Affiliation(s)
- A Lunkes
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, Illkirch, CU de Strasbourg, France
| | | | | | | | | | | | | |
Collapse
|