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Xu J, Zhang D, Ma Y, Du H, Wang Y, Luo W, Wang R, Yi F. ROS in diabetic atria regulate SK2 degradation by Atrogin-1 through the NF-κB signaling pathway. J Biol Chem 2024; 300:105735. [PMID: 38336298 PMCID: PMC10938124 DOI: 10.1016/j.jbc.2024.105735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/13/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
One of the independent risk factors for atrial fibrillation is diabetes mellitus (DM); however, the underlying mechanisms causing atrial fibrillation in DM are unknown. The underlying mechanism of Atrogin-1-mediated SK2 degradation and associated signaling pathways are unclear. The aim of this study was to elucidate the relationship among reactive oxygen species (ROS), the NF-κB signaling pathway, and Atrogin-1 protein expression in the atrial myocardia of DM mice. We found that SK2 expression was downregulated comitant with increased ROS generation and enhanced NF-κB signaling activation in the atrial cardiomyocytes of DM mice. These observations were mimicked by exogenously applicating H2O2 and by high glucose culture conditions in HL-1 cells. Inhibition of ROS production by diphenyleneiodonium chloride or silencing of NF-κB by siRNA decreased the protein expression of NF-κB and Atrogin-1 and increased that of SK2 in HL-1 cells with high glucose culture. Moreover, chromatin immunoprecipitation assay demonstrated that NF-κB/p65 directly binds to the promoter of the FBXO32 gene (encoding Atrogin-1), regulating the FBXO32 transcription. Finally, we evaluated the therapeutic effects of curcumin, known as a NF-κB inhibitor, on Atrogin-1 and SK2 expression in DM mice and confirmed that oral administration of curcumin for 4 weeks significantly suppressed Atrogin-1 expression and protected SK2 expression against hyperglycemia. In summary, the results from this study indicated that the ROS/NF-κB signaling pathway participates in Atrogin-1-mediated SK2 regulation in the atria of streptozotocin-induced DM mice.
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Affiliation(s)
- Jian Xu
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China; Senior Department of Cardiology, The Sixth Medical Center of PLA General Hospital, Beijing, China
| | - Dong Zhang
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yibo Ma
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Hui Du
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Yi Wang
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Wenping Luo
- Institute of Cardiovascular and Vascular Disease, Shaanxi University of Traditional Chinese Medicine, Xianyang, China
| | - Ruxing Wang
- Department of Cardiology, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi, Jiangsu, China
| | - Fu Yi
- Department of Cardiovascular Diseases, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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2
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Charlick JN, Bozadzhieva D, Butler AS, Wilkinson KA, Marrion NV. A single coiled-coil domain mutation in hIKCa channel subunits disrupts preferential formation of heteromeric hSK1:hIKCa channels. Eur J Neurosci 2024; 59:3-16. [PMID: 38018635 PMCID: PMC10952195 DOI: 10.1111/ejn.16189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 09/22/2023] [Accepted: 10/25/2023] [Indexed: 11/30/2023]
Abstract
The expression of IKCa (SK4) channel subunits overlaps with that of SK channel subunits, and it has been proposed that the two related subunits prefer to co-assemble to form heteromeric hSK1:hIKCa channels. This implicates hSK1:hIKCa heteromers in physiological roles that might have been attributed to activation of SK channels. We have used a mutation approach to confirm formation of heterometric hSK1:hIKCa channels. Introduction of residues within hSK1 that were predicted to impart sensitivity to the hIKCa current blocker TRAM-34 changed the pharmacology of functional heteromers. Heteromeric channels formed between wildtype hIKCa and mutant hSK1 subunits displayed a significantly higher sensitivity and maximum block to addition of TRAM-34 than heteromers formed between wildtype subunits. Heteromer formation was disrupted by a single point mutation within one COOH-terminal coiled-coil domain of the hIKCa channel subunit. This mutation only disrupted the formation of hSK1:hIKCa heteromeric channels, without affecting the formation of homomeric hIKCa channels. Finally, the Ca2+ gating sensitivity of heteromeric hSK1:hIKCa channels was found to be significantly lower than the Ca2+ gating sensitivity of homomeric hIKCa channels. These data confirmed the preferred formation of heteromeric channels that results from COOH-terminal interactions between subunits. The distinct sensitivity of the heteromer to activation by Ca2+ suggests that heteromeric channels fulfil a distinct function within those neurons that express both subunits.
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Affiliation(s)
- James N. Charlick
- School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - Daniella Bozadzhieva
- School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - Andrew S. Butler
- School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - Kevin A. Wilkinson
- School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
| | - Neil V. Marrion
- School of Physiology, Pharmacology and NeuroscienceUniversity of BristolBristolUK
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3
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Tsai WC, Lin YH, Kuo CH, Jhuo SJ, Shih RY, Wu CC, Liu IH, Huang TC, Liu RM, Lin TH, Su HM, Lai WT, Lee CH, Wu BN, Lin SF, Lee HC. Up-regulated small-conductance calcium-activated potassium currents contribute to atrial arrhythmogenesis in high-fat feeding mice. Europace 2023; 26:euae004. [PMID: 38195705 PMCID: PMC10825893 DOI: 10.1093/europace/euae004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Revised: 12/04/2023] [Accepted: 12/28/2023] [Indexed: 01/11/2024] Open
Abstract
AIMS Metabolic syndrome (MetS) is associated with arrhythmias and cardiovascular mortality. Arrhythmogenesis in MetS results from atrial structural and electrical remodelling. The small-conductance Ca2+-activated K+ (SK) currents modulate atrial repolarization and may influence atrial arrhythmogenicity. This study investigated the regulation of SK current perturbed by a high-fat diet (HFD) to mimic MetS. METHODS AND RESULTS Thirty mice were divided into two groups that were fed with normal chow (CTL) and HFD for 4 months. Electrocardiography and echocardiography were used to detect cardiac electrical and structure remodelling. Atrial action potential duration (APD) and calcium transient duration (CaTD) were measured by optical mapping of Langendorff-perfused mice hearts. Atrial fibrillation (AF) inducibility and duration were assessed by burst pacing. Whole-cell patch clamp was performed in primarily isolated atrial myocytes for SK current density. The SK current density is higher in atrial myocytes from HFD than in CTL mice (P ≤ 0.037). The RNA and protein expression of SK channels are increased in HFD mice (P ≤ 0.041 and P ≤ 0.011, respectively). Action potential duration is shortened in HFD compared with CTL (P ≤ 0.015). The shortening of the atrial APD in HFD is reversed by the application of 100 nM apamin (P ≤ 0.043). Compared with CTL, CaTD is greater in HFD atria (P ≤ 0.029). Calcium transient decay (Tau) is significantly higher in HFD than in CTL (P = 0.001). Both APD and CaTD alternans thresholds were higher in HFD (P ≤ 0.043), along with higher inducibility and longer duration of AF in HFD (P ≤ 0.023). CONCLUSION Up-regulation of apamin-sensitive SK currents plays a partial role in the atrial arrhythmogenicity of HFD mice.
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Affiliation(s)
- Wei-Chung Tsai
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Yi-Hsiung Lin
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
- Center for Lipid Biosciences, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan
| | - Chia-Hao Kuo
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Shih-Jie Jhuo
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Ruo-Yun Shih
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Chun-Chieh Wu
- Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - I Hsin Liu
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Tien-Chi Huang
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Ren-Ming Liu
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Tsung-Hsien Lin
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
- Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Ho-Ming Su
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Wen-Ter Lai
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
| | - Chien-Hung Lee
- Department of Public Health, College of Health Science, Kaohsiung Medical University, Kaohsiung, Taiwan
- Research Center for Precision Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Bin-Nan Wu
- Department of Pharmacology, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Shien-Fong Lin
- Institute of Biomedical Engineering, National Yang Ming Chiao-Tung University, No. 1001, Daxue Rd. East Dist., Hsinchu City 300093, Taiwan
| | - Hsiang-Chun Lee
- Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, No. 100, Tzi-You 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
- Department of Internal Medicine, School of Medicine, College of Medicine, Kaohsiung Medical University, No. 100, Shih-Chuan 1st Road, Sanmin Dist., Kaohsiung City 80708, Taiwan
- Lipid Science and Aging Research Center, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Institute/Center of Medical Science and Technology, National Sun Yat-sen University, No. 70 Lien-hai Road, Kaohsiung 804201, Taiwan
- Graduate Institute of Animal Vaccine Technology, National Pingtung University of Science and Technology, 1, Shuefu Road, Neipu, Pingtung 912301, Taiwan
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Mulholland PJ, Padula AE, Wilhelm LJ, Park B, Grant KA, Ferguson BM, Cervera-Juanes R. Cross-species epigenetic regulation of nucleus accumbens KCNN3 transcripts by excessive ethanol drinking. Transl Psychiatry 2023; 13:364. [PMID: 38012158 PMCID: PMC10682415 DOI: 10.1038/s41398-023-02676-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 11/14/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
The underlying genetic and epigenetic mechanisms driving functional adaptations in neuronal excitability and excessive alcohol intake are poorly understood. Small-conductance Ca2+-activated K+ (KCa2 or SK) channels encoded by the KCNN family of genes have emerged from preclinical studies as a key contributor to alcohol-induced functional neuroadaptations in alcohol-drinking monkeys and alcohol-dependent mice. Here, this cross-species analysis focused on KCNN3 DNA methylation, gene expression, and single nucleotide polymorphisms, including alternative promoters in KCNN3, that could influence surface trafficking and function of KCa2 channels. Bisulfite sequencing analysis of the nucleus accumbens tissue from alcohol-drinking monkeys and alcohol-dependent mice revealed a differentially methylated region in exon 1A of KCNN3 that overlaps with a predicted promoter sequence. The hypermethylation of KCNN3 in the accumbens paralleled an increase in the expression of alternative transcripts that encode apamin-insensitive and dominant-negative KCa2 channel isoforms. A polymorphic repeat in macaque KCNN3 encoded by exon 1 did not correlate with alcohol drinking. At the protein level, KCa2.3 channel expression in the accumbens was significantly reduced in very heavy-drinking monkeys. Together, our cross-species findings on epigenetic dysregulation of KCNN3 represent a complex mechanism that utilizes alternative promoters to potentially impact the firing of accumbens neurons. Thus, these results provide support for hypermethylation of KCNN3 as a possible key molecular mechanism underlying harmful alcohol intake and alcohol use disorder.
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Affiliation(s)
- Patrick J Mulholland
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Audrey E Padula
- Department of Neuroscience, Charleston Alcohol Research Center, Medical University of South Carolina, Charleston, SC, 29425, USA
| | - Larry J Wilhelm
- Department of Translational Neuroscience, Atrium Health Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - Byung Park
- Department of Public Health and Preventive Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Kathleen A Grant
- Department of Neurosciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Betsy M Ferguson
- Department of Neurosciences, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, 97006, USA
| | - Rita Cervera-Juanes
- Department of Translational Neuroscience, Atrium Health Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
- Center for Precision Medicine, Atrium Health Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
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5
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Wang B, Ma L, Guo X, Du S, Feng X, Liang Y, Govindarajalu G, Wu S, Liu T, Li H, Patel S, Bekker A, Hu H, Tao YX. A sensory neuron-specific long non-coding RNA reduces neuropathic pain by rescuing KCNN1 expression. Brain 2023; 146:3866-3884. [PMID: 37012681 PMCID: PMC10473565 DOI: 10.1093/brain/awad110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 02/21/2023] [Accepted: 03/10/2023] [Indexed: 04/05/2023] Open
Abstract
Nerve injury to peripheral somatosensory system causes refractory neuropathic pain. Maladaptive changes of gene expression in primary sensory neurons are considered molecular basis of this disorder. Long non-coding RNAs (lncRNAs) are key regulators of gene transcription; however, their significance in neuropathic pain remains largely elusive.Here, we reported a novel lncRNA, named sensory neuron-specific lncRNA (SS-lncRNA), for its expression exclusively in dorsal root ganglion (DRG) and trigeminal ganglion. SS-lncRNA was predominantly expressed in small DRG neurons and significantly downregulated due to a reduction of early B cell transcription factor 1 in injured DRG after nerve injury. Rescuing this downregulation reversed a decrease of the calcium-activated potassium channel subfamily N member 1 (KCNN1) in injured DRG and alleviated nerve injury-induced nociceptive hypersensitivity. Conversely, DRG downregulation of SS-lncRNA reduced the expression of KCNN1, decreased total potassium currents and afterhyperpolarization currents and increased excitability in DRG neurons and produced neuropathic pain symptoms.Mechanistically, downregulated SS-lncRNA resulted in the reductions of its binding to Kcnn1 promoter and heterogeneous nuclear ribonucleoprotein M (hnRNPM), consequent recruitment of less hnRNPM to the Kcnn1 promoter and silence of Kcnn1 gene transcription in injured DRG.These findings indicate that SS-lncRNA may relieve neuropathic pain through hnRNPM-mediated KCNN1 rescue in injured DRG and offer a novel therapeutic strategy specific for this disorder.
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Affiliation(s)
- Bing Wang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Longfei Ma
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Xinying Guo
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Shibin Du
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Xiaozhou Feng
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Yingping Liang
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Gokulapriya Govindarajalu
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Shaogen Wu
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Tong Liu
- Center for Advanced Proteomics Research, Departments of Biochemistry, Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Hong Li
- Center for Advanced Proteomics Research, Departments of Biochemistry, Microbiology and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Shivam Patel
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Alex Bekker
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Huijuan Hu
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
- Department of Physiology, Pharmacology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
| | - Yuan-Xiang Tao
- Department of Anesthesiology, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
- Department of Physiology, Pharmacology and Neuroscience, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
- Department of Cell Biology and Molecular Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ 07103, USA
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d’Apolito M, Ceccarini C, Savino R, Adipietro I, di Bari I, Santacroce R, Curcetti M, D’Andrea G, Croce AI, Cesarano C, Polito AN, Margaglione M. A Novel KCNN2 Variant in a Family with Essential Tremor Plus: Clinical Characteristics and In Silico Analysis. Genes (Basel) 2023; 14:1380. [PMID: 37510285 PMCID: PMC10379157 DOI: 10.3390/genes14071380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/30/2023] Open
Abstract
BACKGROUND Essential tremor (ET) is one of the more common movement disorders. Current diagnosis is solely based on clinical findings. ET appears to be inherited in an autosomal dominant pattern. Several loci on specific chromosomes have been studied by linkage analysis, but the causes of essential tremor are still unknown in many patients. Genetic studies described the association of several genes with familial ET. However, they were found only in distinct families, suggesting that some can be private pathogenic variants. AIM OF THE STUDY to characterize the phenotype of an Italian family with ET and identify the genetic variant associated. METHODS Clinical and genetic examinations were performed. Genetic testing was done with whole-exome sequencing (WES) using the Illumina platform. Bidirectional capillary Sanger sequencing was used to investigate the presence of variant in all affected members of the family. In silico prediction of pathogenicity was used to study the effect of gene variants on protein structure. RESULTS The proband was a 15-year-old boy. The patient was the first of two children of a non-consanguineous couple. Family history was remarkable for tremor in the mother line. His mother suffered from bilateral upper extremity kinetic tremors (since she was 20 years old), anxiety, and depression. Other relatives referred bilateral upper extremity tremors. In the index case, WES analysis performed supposing a dominant mode of inheritance, identified a novel heterozygous missense variant in potassium calcium-activated channel subfamily N member 2 (KCNN2) (NM_021614.3: c.1145G>A, p.Gly382Asp). In the pedigree investigation, all carriers of the gene variant had ET and showed variable expressivity, the elder symptomatic relative showing cognitive impairment and hallucinations in the last decade, in addition to tremor since a young age. The amino acid residue #382 is located in a transmembrane region and in silico analysis suggested a causative role for the variant. Modelling of the mutant protein structure showed that the variant causes a clash in the protein structure. Therefore, the variant could cause a conformational change that alters the ability of the protein in the modulation of ion channels Conclusions: The KCNN2 gene variant identified could be associated with ET. The variant could modify a voltage-independent potassium channel activated by intracellular calcium.
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Affiliation(s)
- Maria d’Apolito
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Caterina Ceccarini
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Rosa Savino
- Neuropsychiatry for Child and Adolescent Unit, Department of Woman and Child, Policlinico Riuniti, 70122 Foggia, Italy; (R.S.); (A.N.P.)
| | - Iolanda Adipietro
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Ighli di Bari
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Rosa Santacroce
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Maria Curcetti
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Giovanna D’Andrea
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Anna-Irma Croce
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Carla Cesarano
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
| | - Anna Nunzia Polito
- Neuropsychiatry for Child and Adolescent Unit, Department of Woman and Child, Policlinico Riuniti, 70122 Foggia, Italy; (R.S.); (A.N.P.)
| | - Maurizio Margaglione
- Medical Genetics, Department of Clinical and Experimental Medicine, University of Foggia, 70122 Foggia, Italy; (M.d.); (C.C.); (I.A.); (I.d.B.); (R.S.); (M.C.); (G.D.); (A.-I.C.); (C.C.)
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7
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Nam YW, Rahman MA, Yang G, Orfali R, Cui M, Zhang M. Loss-of-function K Ca2.2 mutations abolish channel activity. Am J Physiol Cell Physiol 2023; 324:C658-C664. [PMID: 36717104 PMCID: PMC10069973 DOI: 10.1152/ajpcell.00584.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/23/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023]
Abstract
Small-conductance Ca2+-activated potassium channels subtype 2 (KCa2.2, also called SK2) are operated exclusively by a Ca2+-calmodulin gating mechanism. Heterozygous genetic mutations of KCa2.2 channels have been associated with autosomal dominant neurodevelopmental disorders including cerebellar ataxia and tremor in humans and rodents. Taking advantage of these pathogenic mutations, we performed structure-function studies of the rat KCa2.2 channel. No measurable current was detected from HEK293 cells heterologously expressing these pathogenic KCa2.2 mutants. When coexpressed with the KCa2.2_WT channel, mutations of the pore-lining amino acid residues (I360M, Y362C, G363S, and I389V) and two proline substitutions (L174P and L433P) dominant negatively suppressed and completely abolished the activity of the coexpressed KCa2.2_WT channel. Coexpression of the KCa2.2_I289N and the KCa2.2_WT channels reduced the apparent Ca2+ sensitivity compared with the KCa2.2_WT channel, which was rescued by a KCa2.2 positive modulator.
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Affiliation(s)
- Young-Woo Nam
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California, United States
| | - Mohammad Asikur Rahman
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California, United States
| | - Grace Yang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California, United States
| | - Razan Orfali
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California, United States
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University School of Pharmacy, Boston, Massachusetts, United States
| | - Miao Zhang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, California, United States
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Nam YW, Downey M, Rahman MA, Cui M, Zhang M. Channelopathy of small- and intermediate-conductance Ca 2+-activated K + channels. Acta Pharmacol Sin 2023; 44:259-267. [PMID: 35715699 PMCID: PMC9889811 DOI: 10.1038/s41401-022-00935-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Accepted: 05/31/2022] [Indexed: 02/04/2023] Open
Abstract
Small- and intermediate-conductance Ca2+-activated K+ (KCa2.x/KCa3.1 also called SK/IK) channels are gated exclusively by intracellular Ca2+. The Ca2+ binding protein calmodulin confers sub-micromolar Ca2+ sensitivity to the channel-calmodulin complex. The calmodulin C-lobe is constitutively associated with the proximal C-terminus of the channel. Interactions between calmodulin N-lobe and the channel S4-S5 linker are Ca2+-dependent, which subsequently trigger conformational changes in the channel pore and open the gate. KCNN genes encode four subtypes, including KCNN1 for KCa2.1 (SK1), KCNN2 for KCa2.2 (SK2), KCNN3 for KCa2.3 (SK3), and KCNN4 for KCa3.1 (IK). The three KCa2.x channel subtypes are expressed in the central nervous system and the heart. The KCa3.1 subtype is expressed in the erythrocytes and the lymphocytes, among other peripheral tissues. The impact of dysfunctional KCa2.x/KCa3.1 channels on human health has not been well documented. Human loss-of-function KCa2.2 mutations have been linked with neurodevelopmental disorders. Human gain-of-function mutations that increase the apparent Ca2+ sensitivity of KCa2.3 and KCa3.1 channels have been associated with Zimmermann-Laband syndrome and hereditary xerocytosis, respectively. This review article discusses the physiological significance of KCa2.x/KCa3.1 channels, the pathophysiology of the diseases linked with KCa2.x/KCa3.1 mutations, the structure-function relationship of the mutant KCa2.x/KCa3.1 channels, and potential pharmacological therapeutics for the KCa2.x/KCa3.1 channelopathy.
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Affiliation(s)
- Young-Woo Nam
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, 92618, USA
| | - Myles Downey
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, 92618, USA
| | - Mohammad Asikur Rahman
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, 92618, USA
| | - Meng Cui
- Department of Pharmaceutical Sciences, Northeastern University School of Pharmacy, Boston, MA, 02115, USA
| | - Miao Zhang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, 92618, USA.
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9
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Halling DB, Philpo AE, Aldrich RW. Calcium dependence of both lobes of calmodulin is involved in binding to a cytoplasmic domain of SK channels. eLife 2022; 11:e81303. [PMID: 36583726 PMCID: PMC9803350 DOI: 10.7554/elife.81303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 12/15/2022] [Indexed: 12/31/2022] Open
Abstract
KCa2.1-3 Ca2+-activated K+-channels (SK) require calmodulin to gate in response to cellular Ca2+. A model for SK gating proposes that the N-terminal domain (N-lobe) of calmodulin is required for activation, but an immobile C-terminal domain (C-lobe) has constitutive, Ca2+-independent binding. Although structures support a domain-driven hypothesis of SK gate activation by calmodulin, only a partial understanding is possible without measuring both channel activity and protein binding. We measured SK2 (KCa2.2) activity using inside-out patch recordings. Currents from calmodulin-disrupted SK2 channels can be restored with exogenously applied calmodulin. We find that SK2 activity only approaches full activation with full-length calmodulin with both an N- and a C-lobe. We measured calmodulin binding to a C-terminal SK peptide (SKp) using both composition-gradient multi-angle light-scattering and tryptophan emission spectra. Isolated lobes bind to SKp with high affinity, but isolated lobes do not rescue SK2 activity. Consistent with earlier models, N-lobe binding to SKp is stronger in Ca2+, and C-lobe-binding affinity is strong independent of Ca2+. However, a native tryptophan in SKp is sensitive to Ca2+ binding to both the N- and C-lobes of calmodulin at Ca2+ concentrations that activate SK2, demonstrating that the C-lobe interaction with SKp changes with Ca2+. Our peptide-binding data and electrophysiology show that SK gating models need deeper scrutiny. We suggest that the Ca2+-dependent associations of both lobes of calmodulin to SKp are crucial events during gating. Additional investigations are necessary to complete a mechanistic gating model consistent with binding, physiology, and structure.
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Affiliation(s)
- David B Halling
- Department of Neuroscience, The University of Texas at AustinAustinUnited States
| | - Ashley E Philpo
- Department of Neuroscience, The University of Texas at AustinAustinUnited States
| | - Richard W Aldrich
- Department of Neuroscience, The University of Texas at AustinAustinUnited States
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10
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Wu N, Li C, Xu B, Xiang Y, Jia X, Yuan Z, Wu L, Zhong L, Li Y. Circular RNA mmu_circ_0005019 inhibits fibrosis of cardiac fibroblasts and reverses electrical remodeling of cardiomyocytes. BMC Cardiovasc Disord 2021; 21:308. [PMID: 34154526 PMCID: PMC8215745 DOI: 10.1186/s12872-021-02128-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 06/10/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Circular RNA (circRNA) have been reported to play important roles in cardiovascular diseases including myocardial infarction and heart failure. However, the role of circRNA in atrial fibrillation (AF) has rarely been investigated. We recently found a circRNA hsa_circ_0099734 was significantly differentially expressed in the AF patients atrial tissues compared to paired control. We aim to investigate the functional role and molecular mechanisms of mmu_circ_0005019 which is the homologous circRNA in mice of hsa_circ_0099734 in AF. METHODS In order to investigate the effect of mmu_circ_0005019 on the proliferation, migration, differentiation into myofibroblasts and expression of collagen of cardiac fibroblasts, and the effect of mmu_circ_0005019 on the apoptosis and expression of Ito, INA and SK3 of cardiomyocytes, gain- and loss-of-function of cell models were established in mice cardiac fibroblasts and HL-1 atrial myocytes. Dual-luciferase reporter assays and RIP were performed to verify the binding effects between mmu_circ_0005019 and its target microRNA (miRNA). RESULTS In cardiac fibroblasts, mmu_circ_0005019 showed inhibitory effects on cell proliferation and migration. In cardiomyocytes, overexpression of mmu_circ_0005019 promoted Kcnd1, Scn5a and Kcnn3 expression. Knockdown of mmu_circ_0005019 inhibited the expression of Kcnd1, Kcnd3, Scn5a and Kcnn3. Mechanistically, mmu_circ_0005019 exerted biological functions by acting as a miR-499-5p sponge to regulate the expression of its target gene Kcnn3. CONCLUSIONS Our findings highlight mmu_circ_0005019 played a protective role in AF development and might serve as an attractive candidate target for AF treatment.
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Affiliation(s)
- Na Wu
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China
| | - Chengying Li
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China
| | - Bin Xu
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China
| | - Ying Xiang
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China
| | - Xiaoyue Jia
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China
| | - Zhiquan Yuan
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China
| | - Long Wu
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China
| | - Li Zhong
- Cardiovascular Disease Center, Third Affiliated Hospital of Chongqing Medical University, Chongqing, 401120, People's Republic of China
| | - Yafei Li
- Department of Epidemiology, College of Preventive Medicine, Army Medical University (Third Military Medical University), NO. 30 Gaotanyan Street, Chongqing, 400038, People's Republic of China.
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11
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Chen H, Xia F, Chen X, Cai Y, Jin Z. Ablation of small conductance calcium-activated potassium type-2 channel (SK 2) delays occurrence of bupivacaine-induced cardiotoxicity in isolated mouse hearts. Hum Exp Toxicol 2021; 40:464-471. [PMID: 32909839 DOI: 10.1177/0960327120958102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bupivacaine is frequently used for conducting regional anesthesia. When accidentally injected or excessively absorbed into circulation, bupivacaine can induce severe arrhythmia and potentially lead to cardiac arrest. The specific mechanisms underlying this cardiotoxicity, however, remain to be clarified. We transfected HEK-293 cells to express the small conductance calcium-activated potassium type-2 channel (SK2), and used a whole-cell patch clamp method in order to explore how bupivacaine affected these channels. We subsequently used SK2 knockout mice to explore the relevance of SK2 channels in bupivacaine-induced cardiotoxicity in isolating mouse hearts, mounting them on a Langendorff apparatus, and perfusing them with bupivacaine. Using this system, arrhythmia, asystole, and cardiac functions were monitored. We observed dose-dependent inhibition of SK2 channels by bupivacaine: half-maximal inhibitory concentration (IC50) value = 18.6 μM (95% CI 10.8-32.1). When SK2 knockout (SK2 -/-) or wild-type (WT) mice were perfused with Krebs-Henseleit buffer (KHB), we did not observe any instances of arrhythmia. When SK2 -/- mice or WT were perfused with KHB containing bupivacaine (40 μM), the time to arrhythmia (Tarrhythmia) and time to asystole (Tasystole) were both significantly longer in SK2 -/- mice relative to WT mice (P < 0.001). Similarly, SK2 -/- mice exhibited a significantly longer time to 25%, 50%, and 75% reductions in heart rate (HR) and rate-pressure product (RPP) relative to WT mice following bupivacaine perfusion (P < 0.001). These results reveal that bupivacaine was able to mediate a dose-dependent inhibition of SK2 channels in HEK-293 cells, and deletion of SK2 channels can delay bupivacaine-induced cardiotoxicity in isolated mouse hearts.
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Affiliation(s)
- H Chen
- Department of Anesthesiology, the 89657First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - F Xia
- Department of Anesthesiology, the 89657First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - X Chen
- Department of Anesthesiology, the 89657First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Y Cai
- Department of Anesthesiology, the 89657First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
| | - Z Jin
- Department of Anesthesiology, the 89657First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China
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12
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Sun J, Liu Y, Baudry M, Bi X. SK2 channel regulation of neuronal excitability, synaptic transmission, and brain rhythmic activity in health and diseases. Biochim Biophys Acta Mol Cell Res 2020; 1867:118834. [PMID: 32860835 PMCID: PMC7541745 DOI: 10.1016/j.bbamcr.2020.118834] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/13/2020] [Accepted: 08/19/2020] [Indexed: 11/20/2022]
Abstract
Small conductance calcium-activated potassium channels (SKs) are solely activated by intracellular Ca2+ and their activation leads to potassium efflux, thereby repolarizing/hyperpolarizing membrane potential. Thus, these channels play a critical role in synaptic transmission, and consequently in information transmission along the neuronal circuits expressing them. SKs are widely but not homogeneously distributed in the central nervous system (CNS). Activation of SKs requires submicromolar cytoplasmic Ca2+ concentrations, which are reached following either Ca2+ release from intracellular Ca2+ stores or influx through Ca2+ permeable membrane channels. Both Ca2+ sensitivity and synaptic levels of SKs are regulated by protein kinases and phosphatases, and degradation pathways. SKs in turn control the activity of multiple Ca2+ channels. They are therefore critically involved in coordinating diverse Ca2+ signaling pathways and controlling Ca2+ signal amplitude and duration. This review highlights recent advances in our understanding of the regulation of SK2 channels and of their roles in normal brain functions, including synaptic plasticity, learning and memory, and rhythmic activities. It will also discuss how alterations in their expression and regulation might contribute to various brain disorders such as Angelman Syndrome, Alzheimer's disease and Parkinson's disease.
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Affiliation(s)
- Jiandong Sun
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, United States of America; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, United States of America
| | - Yan Liu
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, United States of America; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, United States of America
| | - Michel Baudry
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, United States of America; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, United States of America
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific, Western University of Health Sciences, Pomona, CA 91766, United States of America; Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, United States of America.
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13
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Mousa MH, Elbasiouny SM. Dendritic distributions of L-type Ca 2+ and SK L channels in spinal motoneurons: a simulation study. J Neurophysiol 2020; 124:1285-1307. [PMID: 32937080 PMCID: PMC7717167 DOI: 10.1152/jn.00169.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 12/12/2022] Open
Abstract
Persistent inward currents are important to motoneuron excitability and firing behaviors and also have been implicated in excitotoxicity. In particular, L-type Ca2+ channels, usually located on motoneuron dendrites, play a primary role in amplification of synaptic inputs. However, recent experimental findings on L-type Ca2+ channel behaviors challenge some fundamental assumptions that have been used in interpreting experimental and computational modeling data. Thus, the objectives of this study were to incorporate recent experimental data into an updated, high-fidelity computational model in order to explain apparent inconsistencies and to better elucidate the spatial distributions, expression patterns, and functional roles of L-type Ca2+ and SKL channels. Specifically, the updated model incorporated asymmetric channel activation/deactivation kinetics, depolarization-dependent facilitation, randomness in channel gating, and coactivation of SKL channels. Our simulation results suggest that L-type Ca2+ and SKL channels colocalize primarily on distal dendrites of motoneurons in a punctate expression. Also, punctate expression, as opposed to a homogeneous expression, provides high synaptic current amplification, limits bistability and firing rates, and robustly regulates the Ca2+ persistent inward current, thereby reducing risk of excitotoxicity. The hysteresis and bistability observed experimentally in current-voltage and frequency-current relationships result from the L-type Ca2+ channels' distal location and intrinsic warm-up. Accordingly, our results indicate that punctate expression of L-type Ca2+ and SKL channels is a potent mechanism for regulating excitability, which would provide a strong neuroprotective effect. Our results could provide broader insights into the functional significance of warm-up and punctate expression of ion channels to regulation of cell excitability.NEW & NOTEWORTHY Recent experimental findings on L-type Ca2+ channels challenge fundamental assumptions used in interpreting experimental and computational modeling data. Here, we incorporated recent experimental data into an updated, high-fidelity computational model to explain apparent inconsistencies and better elucidate the distributions, expression patterns, and functional roles of L-type Ca2+ and SKL channels. Our results indicate that punctate expression of L-type Ca2+ and SKL channels is a potent mechanism for regulating motoneuron excitability, providing a strong neuroprotective effect.
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Affiliation(s)
- Mohamed H Mousa
- Department of Systems and Biomedical Engineering, Faculty of Engineering, Cairo University, Cairo, Egypt
- Department of Biomedical, Industrial, and Human Factors Engineering, College of Engineering and Computer Science, Wright State University, Dayton, Ohio
| | - Sherif M Elbasiouny
- Department of Neuroscience, Cell Biology, and Physiology, Boonshoft School of Medicine and College of Science and Mathematics, Wright State University, Dayton, Ohio
- Department of Biomedical, Industrial, and Human Factors Engineering, College of Engineering and Computer Science, Wright State University, Dayton, Ohio
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14
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Gill DF, Hansel C. Muscarinic Modulation of SK2-Type K + Channels Promotes Intrinsic Plasticity in L2/3 Pyramidal Neurons of the Mouse Primary Somatosensory Cortex. eNeuro 2020; 7:ENEURO.0453-19.2020. [PMID: 32005752 PMCID: PMC7294454 DOI: 10.1523/eneuro.0453-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 01/09/2020] [Accepted: 01/17/2020] [Indexed: 11/21/2022] Open
Abstract
Muscarinic acetylcholine receptors (mAChRs) inhibit small-conductance calcium-activated K+ channels (SK channels) and enhance synaptic weight via this mechanism. SK channels are also involved in activity-dependent plasticity of membrane excitability ("intrinsic plasticity"). Here, we investigate whether mAChR activation can drive SK channel-dependent intrinsic plasticity in L2/3 cortical pyramidal neurons. Using whole-cell patch-clamp recordings from these neurons in slices prepared from mouse primary somatosensory cortex (S1), we find that brief bath application of the mAChR agonist oxotremorine-m (oxo-m) causes long-term enhancement of excitability in wild-type mice that is not observed in mice deficient of SK channels of the SK2 isoform. Similarly, repeated injection of depolarizing current pulses into the soma triggers intrinsic plasticity that is absent from SK2 null mice. Intrinsic plasticity lowers spike frequency adaptation and attenuation of spike firing upon prolonged activation, consistent with SK channel modulation. Depolarization-induced plasticity is prevented by bath application of the protein kinase A (PKA) inhibitor H89, and the casein kinase 2 (CK2) inhibitor TBB, respectively. These findings point toward a recruitment of two known signaling pathways in SK2 regulation: SK channel trafficking (PKA) and reduction of the calcium sensitivity (CK2). Using mice with an inactivation of CaMKII (T305D mice), we show that intrinsic plasticity does not require CaMKII. Finally, we demonstrate that repeated injection of depolarizing pulses in the presence of oxo-m causes intrinsic plasticity that surpasses the plasticity amplitude reached by either manipulation alone. Our findings show that muscarinic activation enhances membrane excitability in L2/3 pyramidal neurons via a downregulation of SK2 channels.
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Affiliation(s)
- Daniel F Gill
- Department of Neurobiology, University of Chicago, Chicago, IL 60637
| | - Christian Hansel
- Department of Neurobiology, University of Chicago, Chicago, IL 60637
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15
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Jiang T, Wang YN, Qu Q, Qi TT, Chen YD, Qu J. Association between gene variants and the recurrence of atrial fibrillation: An updated meta-analysis. Medicine (Baltimore) 2019; 98:e15953. [PMID: 31169720 PMCID: PMC6571381 DOI: 10.1097/md.0000000000015953] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 02/10/2019] [Accepted: 05/15/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Studies showed the controversial results about the effect of common genetic polymorphisms on the atrial fibrillation (AF) recurrence. We performed the systematic review and meta-analysis to qualify the association between common genetic polymorphisms and AF recurrence. METHODS Articles were systematically retrieved PubMed, Web of Science, EMBASE, Wanfang, and CNKI database and 9 studies including 3204 patients were enrolled in our meta-analysis. RESULTS Results showed that the associations were significant under rs2200733 3 genetic models (TT vs CC: odds ratio [OR] [confidence interval [CI]] = 1.336 [1.061-1.683], P = .014; CT vs CC: OR [CI] = 0.759 [0.614-0.937], P = .01; TT vs CT + CC: OR [CI] = 2.308 [1.440-3.700], P = .001). The association was significant under rs10033464 genetic model (TT vs GG: OR [CI] = 1.517 [1.165-1.976], P = .002). CONCLUSIONS Rs13376333 on chromosome 1q21 (in KCNN3), rs7193343 and rs2106261 on chromosome 16q22 (in ZFHX3) were not associated with AF recurrence in our meta-analysis. In total, our meta-analysis found that rs2200733 and rs10033464 on chromosome 4q25 (near PITX2) were associated with the risk of AF recurrence.
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Affiliation(s)
- Tao Jiang
- Department of Cardiovascular Medicine
| | - Ya-Nan Wang
- Department of Respiratory, Hospital of Laiwu Iron and Steel Co. Ltd, Laiwu
| | - Qiang Qu
- Department of Pharmacy, Xiangya Hospital
| | - Ting-Ting Qi
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Institute of Clinical Pharmacy, Central South University, Changsha
| | - Yun-Dai Chen
- Department of Cardiovascular Medicine, The General Hospital of the People's Liberation Army, Beijing, People's Republic of China
| | - Jian Qu
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Institute of Clinical Pharmacy, Central South University, Changsha
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16
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Guo Y, Perez AA, Hazelett DJ, Coetzee GA, Rhie SK, Farnham PJ. CRISPR-mediated deletion of prostate cancer risk-associated CTCF loop anchors identifies repressive chromatin loops. Genome Biol 2018; 19:160. [PMID: 30296942 PMCID: PMC6176514 DOI: 10.1186/s13059-018-1531-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 09/09/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Recent genome-wide association studies (GWAS) have identified more than 100 loci associated with increased risk of prostate cancer, most of which are in non-coding regions of the genome. Understanding the function of these non-coding risk loci is critical to elucidate the genetic susceptibility to prostate cancer. RESULTS We generate genome-wide regulatory element maps and performed genome-wide chromosome confirmation capture assays (in situ Hi-C) in normal and tumorigenic prostate cells. Using this information, we annotate the regulatory potential of 2,181 fine-mapped prostate cancer risk-associated SNPs and predict a set of target genes that are regulated by prostate cancer risk-related H3K27Ac-mediated loops. We next identify prostate cancer risk-associated CTCF sites involved in long-range chromatin loops. We use CRISPR-mediated deletion to remove prostate cancer risk-associated CTCF anchor regions and the CTCF anchor regions looped to the prostate cancer risk-associated CTCF sites, and we observe up to 100-fold increases in expression of genes within the loops when the prostate cancer risk-associated CTCF anchor regions are deleted. CONCLUSIONS We identify GWAS risk loci involved in long-range loops that function to repress gene expression within chromatin loops. Our studies provide new insights into the genetic susceptibility to prostate cancer.
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Affiliation(s)
- Yu Guo
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT 6503, Los Angeles, CA 90089-9601 USA
| | - Andrew A. Perez
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT 6503, Los Angeles, CA 90089-9601 USA
| | - Dennis J. Hazelett
- Department of Biomedical Sciences and the Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048 USA
| | | | - Suhn Kyong Rhie
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT 6503, Los Angeles, CA 90089-9601 USA
| | - Peggy J. Farnham
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT 6503, Los Angeles, CA 90089-9601 USA
- Department of Biochemistry and Molecular Medicine and the Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, 1450 Biggy Street, NRT G511B, Los Angeles, CA 90089-9601 USA
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17
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Ko JS, Guo S, Hassel J, Celestino-Soper P, Lynnes TC, Tisdale JE, Zheng JJ, Taylor SE, Foroud T, Murray MD, Kovacs RJ, Li X, Lin SF, Chen Z, Vatta M, Chen PS, Rubart M. Ondansetron blocks wild-type and p.F503L variant small-conductance Ca 2+-activated K + channels. Am J Physiol Heart Circ Physiol 2018; 315:H375-H388. [PMID: 29677462 PMCID: PMC6139629 DOI: 10.1152/ajpheart.00479.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 04/11/2018] [Accepted: 04/11/2018] [Indexed: 01/24/2023]
Abstract
Apamin-sensitive small-conductance Ca2+-activated K+ (SK) current ( IKAS) is encoded by Ca2+-activated K+ channel subfamily N ( KCNN) genes. IKAS importantly contributes to cardiac repolarization in conditions associated with reduced repolarization reserve. To test the hypothesis that IKAS inhibition contributes to drug-induced long QT syndrome (diLQTS), we screened for KCNN variants among patients with diLQTS, determined the properties of heterologously expressed wild-type (WT) and variant KCNN channels, and determined if the 5-HT3 receptor antagonist ondansetron blocks IKAS. We searched 2,306,335 records in the Indiana Network for Patient Care and found 11 patients with diLQTS who had DNA available in the Indiana Biobank. DNA sequencing discovered a heterozygous KCNN2 variant (p.F503L) in a 52-yr-old woman presenting with corrected QT interval prolongation at baseline (473 ms) and further corrected QT interval lengthening (601 ms) after oral administration of ondansetron. That patient was also heterozygous for the p.S38G and p.P2835S variants of the QT-controlling genes KCNE1 and ankyrin 2, respectively. Patch-clamp experiments revealed that the p.F503L KCNN2 variant heterologously expressed in human embryonic kidney (HEK)-293 cells augmented Ca2+ sensitivity, increasing IKAS density. The fraction of total F503L-KCNN2 protein retained in the membrane was higher than that of WT KCNN2 protein. Ondansetron at nanomolar concentrations inhibited WT and p.F503L SK2 channels expressed in HEK-293 cells as well as native SK channels in ventricular cardiomyocytes. Ondansetron-induced IKAS inhibition was also demonstrated in Langendorff-perfused murine hearts. In conclusion, the heterozygous p.F503L KCNN2 variant increases Ca2+ sensitivity and IKAS density in transfected HEK-293 cells. Ondansetron at therapeutic (i.e., nanomolar) concentrations is a potent IKAS blocker. NEW & NOTEWORTHY We showed that ondansetron, a 5-HT3 receptor antagonist, blocks small-conductance Ca2+-activated K+ (SK) current. Ondansetron may be useful in controlling arrhythmias in which increased SK current is a likely contributor. However, its SK-blocking effects may also facilitate the development of drug-induced long QT syndrome.
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Affiliation(s)
- Jum-Suk Ko
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
- Wonkwang University School of Medicine and Hospital, Iksan, South Korea
| | - Shuai Guo
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Jonathan Hassel
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Patricia Celestino-Soper
- Department of Medical and Molecular Genetics, Indiana University School of Medicine , Indianapolis, Indiana
| | - Ty C Lynnes
- Department of Medical and Molecular Genetics, Indiana University School of Medicine , Indianapolis, Indiana
| | - James E Tisdale
- Department of Pharmacy Practice, College of Pharmacy, Purdue University , West Lafayette, Indiana
- Division of Clinical Pharmacology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | | | - Stanley E Taylor
- Department of Biostatistics, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Tatiana Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine , Indianapolis, Indiana
| | - Michael D Murray
- Department of Pharmacy Practice, College of Pharmacy, Purdue University , West Lafayette, Indiana
- Regenstrief Institute , Indianapolis, Indiana
| | - Richard J Kovacs
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Xiaochun Li
- Department of Biostatistics, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Shien-Fong Lin
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
- Institute of Biomedical Engineering, National Chiao-Tung University, Hsin-Chu, Taiwan
| | - Zhenhui Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Matteo Vatta
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
- Department of Medical and Molecular Genetics, Indiana University School of Medicine , Indianapolis, Indiana
- Department of Pediatrics, Riley Heart Research Center, Indiana University School of Medicine , Indianapolis, Indiana
| | - Peng-Sheng Chen
- The Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine , Indianapolis, Indiana
| | - Michael Rubart
- Department of Pediatrics, Riley Heart Research Center, Indiana University School of Medicine , Indianapolis, Indiana
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Wang X, Nie Y, Ning S, Shi Y, Zhao Y, Niu S, Guo C, Meng X, Yuan Y. [Rs17042171 at chromosome 4q25 is associated with atrial fibrillation in the Chinese Han population from the central plains]. Zhong Nan Da Xue Xue Bao Yi Xue Ban 2018; 43:594-603. [PMID: 30110000 DOI: 10.11817/j.issn.1672-7347.2018.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To determine the correlations of single nucleotide polymorphisms (SNPs) with atrial fibrillation (AF) in the Chinese Han population from the central plains.
Methods: A total of 168 hospitalized patients, including 56 AF and 112 controls, were recruited in this case-control study. The clinical data were obtained from the medical records. All 5 SNPs, rs337711 in KCNN2, rs11264280 near KCNN3, rs17042171 near PITX2, rs6771157 and rs6795970 in SCN10A, were genotyped using amplification refractory mutation system-polymerase chain reaction or direct sequencing. The χ2 test was used to compare categorical variables and preliminarily examine correlations between the genotype frequencies and AF. Subsequently, a logistic regression model was constructed to determine the associations between the SNPs and AF based on the above screened results. Odds ratios (ORs) and 95% confidence interval (CI) were calculated to assess the strength of the correlations. Moreover, we downloaded the genotype data from the HapMap Project for linkage disequilibrium analysis of rs17042171.
Results: AF patients were likely to be of older age and longer left atrial diameter and had more coronary artery disease and higher hypertension compared with the control group (P<0.05). Among the 5 SNPs, the frequency distribution of genotype AA for rs17042171 was significantly different between the AF and control groups (P<0.05). After adjusting for several covariates, there was still a high risk ratio in patients with the AA genotype compared with the AC+CC genotype (OR: 5.591, 95%CI 2.176 to 14.365, P-B<0.008). Similarly, stratification analysis on the AA genotype demonstrated significant differences between rs17042171 and persistent AF. However, there were not significant correlations between AF and the control groups for the other 4 SNPs (P<0.05).
Conclusion: Rs17042171, near PITX2 on chromosome 4q25, is associated with AF susceptibility in the Chinese Han population from the central plains, suggesting that this SNP can provide a new strategy for clinical diagnosis in AF patients.
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Affiliation(s)
- Xu Wang
- Department of Cardiology, Henan Cardiovascular Hospital, Affiliated to Southern Medical University, Zhengzhou 450016, China
| | - Yali Nie
- Department of Pharmacology, School of Medicine, Zhengzhou University, Zhengzhou 450000, China
| | - Shuwei Ning
- Laboratory of Cardiovascular Disease and Drug Research, Seventh People's Hospital of Zhengzhou , Zhengzhou 450016, China
| | - Yong Shi
- Department of Urology, Seventh People's Hospital of Zhengzhou, Zhengzhou 450016, China
| | - Yujie Zhao
- Department of Cardiology, Seventh People's Hospital of Zhengzhou, Zhengzhou 450016, China
| | - Siquan Niu
- Department of Cardiology, Seventh People's Hospital of Zhengzhou, Zhengzhou 450016, China
| | - Chengxian Guo
- Center of Clinical Pharmacology, Third Xiangya Hospital, Central South University, Changsha 410013, China
| | - Xiangguang Meng
- Laboratory of Cardiovascular Disease and Drug Research, Seventh People's Hospital of Zhengzhou , Zhengzhou 450016, China
| | - Yiqiang Yuan
- Department of Cardiology, Henan Cardiovascular Hospital, Affiliated to Southern Medical University, Zhengzhou 450016, China
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19
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Cho LTY, Alexandrou AJ, Torella R, Knafels J, Hobbs J, Taylor T, Loucif A, Konopacka A, Bell S, Stevens EB, Pandit J, Horst R, Withka JM, Pryde DC, Liu S, Young GT. An Intracellular Allosteric Modulator Binding Pocket in SK2 Ion Channels Is Shared by Multiple Chemotypes. Structure 2018; 26:533-544.e3. [PMID: 29576321 DOI: 10.1016/j.str.2018.02.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/03/2017] [Accepted: 02/23/2018] [Indexed: 01/22/2023]
Abstract
Small conductance potassium (SK) ion channels define neuronal firing rates by conducting the after-hyperpolarization current. They are key targets in developing therapies where neuronal firing rates are dysfunctional, such as in epilepsy, Parkinson's, and amyotrophic lateral sclerosis (ALS). Here, we characterize a binding pocket situated at the intracellular interface of SK2 and calmodulin, which we show to be shared by multiple small-molecule chemotypes. Crystallization of this complex revealed that riluzole (approved for ALS) and an analog of the anti-ataxic agent (4-chloro-phenyl)-[2-(3,5-dimethyl-pyrazol-1-yl)-pyrimidin-4-yl]-amine (CyPPA) bind to and allosterically modulate via this site. Solution-state nuclear magnetic resonance demonstrates that riluzole, NS309, and CyPPA analogs bind at this bipartite pocket. We demonstrate, by patch-clamp electrophysiology, that both classes of ligand interact with overlapping but distinct residues within this pocket. These data define a clinically important site, laying the foundations for further studies of the mechanism of action of riluzole and related molecules.
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Affiliation(s)
- Lily T-Y Cho
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Aristos J Alexandrou
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Rubben Torella
- Pfizer Worldwide Medicinal Chemistry, Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - John Knafels
- Pfizer Structural Biology and Biophysics, Groton, Eastern Point Road, Groton, CT 06340, USA
| | - Jake Hobbs
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Toni Taylor
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Alex Loucif
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Agnieszka Konopacka
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Sigourney Bell
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Edward B Stevens
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Jay Pandit
- Pfizer Structural Biology and Biophysics, Groton, Eastern Point Road, Groton, CT 06340, USA
| | - Reto Horst
- Pfizer Structural Biology and Biophysics, Groton, Eastern Point Road, Groton, CT 06340, USA
| | - Jane M Withka
- Pfizer Structural Biology and Biophysics, Groton, Eastern Point Road, Groton, CT 06340, USA
| | - David C Pryde
- Pfizer Worldwide Medicinal Chemistry, Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK
| | - Shenping Liu
- Pfizer Structural Biology and Biophysics, Groton, Eastern Point Road, Groton, CT 06340, USA.
| | - Gareth T Young
- Pfizer Neuroscience and Pain Research Unit, Granta Park, Great Abington, Cambridge CB21 6GS, UK.
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20
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Muse ED, Wineinger NE, Spencer EG, Peters M, Henderson R, Zhang Y, Barrett PM, Rivera SP, Wohlgemuth JG, Devlin JJ, Shiffman D, Topol EJ. Validation of a genetic risk score for atrial fibrillation: A prospective multicenter cohort study. PLoS Med 2018; 15:e1002525. [PMID: 29534064 PMCID: PMC5849279 DOI: 10.1371/journal.pmed.1002525] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 02/06/2018] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Atrial fibrillation (AF) is the most commonly encountered arrhythmia and is associated with an elevated risk of stroke. Improving the identification of patients with the highest risk for AF to enable appropriate surveillance and treatment, if necessary, is critical to reducing AF-associated morbidity and mortality. Multiple common single nucleotide polymorphisms (SNPs) are unequivocally associated with the lifetime risk of AF. In the current study we aimed to prospectively validate an AF genetic risk score (GRS) in previously undiagnosed patients at risk for AF. METHODS AND FINDINGS Individuals 40 years of age or older with 1 clinical risk factor for AF, presenting with symptoms of AF, or with a first diagnosis of AF, were enrolled for genetic testing and ambulatory cardiac rhythm monitoring with an adhesive patch monitor or a long-term Holter monitor (mean wear time 10 days 21 hours and 13 days 18 hours, respectively). An AF event was the first diagnosis of AF by ECG, patch monitor, or long-term Holter monitor. The AF GRS was determined for each participant based on the weighted contribution of 12 genetic risk loci. Of 904 participants, 85 manifested AF. Their mean age was 66.2 (SD 11.8) years; 38% of participants were male. Participants in the highest quintile of AF GRS were more likely (odds ratio 3.11; 95% CI 1.27-7.58; p = 0.01) to have had an AF event than participants in the lowest quintile after adjusting for age, sex, smoking status, BMI, hypertension, diabetes mellitus, heart failure, and prior myocardial infarction. Study limitations included an ethnically homogenous population, a restricted rhythm monitoring period, and the evolving discovery of SNPs associated with AF. CONCLUSIONS Prospective assessment of a GRS for AF identified participants with elevated risk of AF beyond established clinical criteria. Accordingly, a GRS for AF could be incorporated into overall risk assessment to better identify patients at the highest risk of developing AF, although further testing in larger populations is needed to confirm these findings. TRIAL REGISTRATION ClinicalTrials.gov NCT01970969.
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Affiliation(s)
- Evan D. Muse
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
- Division of Cardiovascular Disease, Scripps Clinic–Scripps Health, La Jolla, California, United States of America
| | - Nathan E. Wineinger
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
| | - Emily G. Spencer
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
| | - Melissa Peters
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
| | - Riley Henderson
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
| | - Yunyue Zhang
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
| | - Paddy M. Barrett
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
| | - Steven P. Rivera
- Quest Diagnostics, San Juan Capistrano, California, United States of America
| | - Jay G. Wohlgemuth
- Quest Diagnostics, San Juan Capistrano, California, United States of America
| | - James J. Devlin
- Quest Diagnostics, San Juan Capistrano, California, United States of America
| | - Dov Shiffman
- Quest Diagnostics, San Juan Capistrano, California, United States of America
| | - Eric J. Topol
- Scripps Translational Science Institute, The Scripps Research Institute, La Jolla, California, United States of America
- Division of Cardiovascular Disease, Scripps Clinic–Scripps Health, La Jolla, California, United States of America
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21
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Hsu J, Gore-Panter S, Tchou G, Castel L, Lovano B, Moravec CS, Pettersson GB, Roselli EE, Gillinov AM, McCurry KR, Smedira NG, Barnard J, Van Wagoner DR, Chung MK, Smith JD. Genetic Control of Left Atrial Gene Expression Yields Insights into the Genetic Susceptibility for Atrial Fibrillation. Circ Genom Precis Med 2018; 11:e002107. [PMID: 29545482 PMCID: PMC5858469 DOI: 10.1161/circgen.118.002107] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 01/23/2018] [Indexed: 02/01/2023]
Abstract
BACKGROUND Genome-wide association studies have identified 23 loci for atrial fibrillation (AF), but the mechanisms responsible for these associations, as well as the causal genes and genetic variants, remain undefined. METHODS To identify the effect of common genetic variants on gene expression that might explain the mechanisms linking genome-wide association loci with AF risk, we performed RNA sequencing of left atrial appendages from a biracial cohort of 265 subjects. RESULTS Combining gene expression data with genome-wide single nucleotide polymorphism data, we found that approximately two-thirds of the expressed genes were regulated in cis by common genetic variants at a false discovery rate of <0.05, defined as cis-expression quantitative trait loci. Twelve of 23 reported AF genome-wide association loci displayed genome-wide significant cis-expression quantitative trait loci, at PRRX1 (chromosome 1q24), SNRNP27 (1q24), CEP68 (2p14), FKBP7 (2q31), KCNN2 (5q22), FAM13B (5q31), CAV1 (7q31), ASAH1 (8p22), MYOZ1 (10q22), C11ORF45 (11q24), TBX5 (12q24), and SYNE2 (14q23), suggesting that altered expression of these genes plays a role in AF susceptibility. Allelic expression imbalance was used as an independent method to characterize the cis-control of gene expression. One thousand two hundred forty-eight of 5153 queried genes had cis-single nucleotide polymorphisms that significantly regulated allelic expression at a false discovery rate of <0.05. CONCLUSIONS We provide a genome-wide catalog of the genetic control of gene expression in human left atrial appendage. These data can be used to confirm the relevance of genome-wide association loci and to direct future functional studies to identify the genes and genetic variants responsible for complex diseases such as AF.
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Affiliation(s)
- Jeffrey Hsu
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Shamone Gore-Panter
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Gregory Tchou
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Laurie Castel
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Beth Lovano
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Christine S Moravec
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Gosta B Pettersson
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Eric E Roselli
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - A Marc Gillinov
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Kenneth R McCurry
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Nicholas G Smedira
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - John Barnard
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - David R Van Wagoner
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Mina K Chung
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH
| | - Jonathan D Smith
- From the Departments of Cellular and Molecular Medicine (J.H., G.T., J.D.S.), Quantitative Health Sciences (J.B.), Molecular Cardiology (S.G.-P., L.C., B.L., C.S.M., D.R.V.W., M.K.C.), Cardiovascular Medicine (C.S.M., D.R.V.W., M.K.C., J.D.S.), and Cardiothoracic Surgery (G.B.P., E.E.R., A.M.G., K.R.M., N.G.S.), Cleveland Clinic, Cleveland, OH.
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Gueguinou M, Crottès D, Chantôme A, Rapetti-Mauss R, Potier-Cartereau M, Clarysse L, Girault A, Fourbon Y, Jézéquel P, Guérin-Charbonnel C, Fromont G, Martin P, Pellissier B, Schiappa R, Chamorey E, Mignen O, Uguen A, Borgese F, Vandier C, Soriani O. The SigmaR1 chaperone drives breast and colorectal cancer cell migration by tuning SK3-dependent Ca 2+ homeostasis. Oncogene 2017; 36:3640-3647. [PMID: 28114279 DOI: 10.1038/onc.2016.501] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/19/2016] [Accepted: 11/28/2016] [Indexed: 12/21/2022]
Abstract
The remodeling of calcium homeostasis contributes to the cancer hallmarks and the molecular mechanisms involved in calcium channel regulation in tumors remain to be characterized. Here, we report that SigmaR1, a stress-activated chaperone, is required to increase calcium influx by triggering the coupling between SK3, a Ca2+-activated K+ channel (KCNN3) and the voltage-independent calcium channel Orai1. We show that SigmaR1 physically binds SK3 in BC cells. Inhibition of SigmaR1 activity, either by molecular silencing or by the use of sigma ligand (igmesine), decreased SK3 current and Ca2+ entry in breast cancer (BC) and colorectal cancer (CRC) cells. Interestingly, SigmaR1 inhibition diminished SK3 and/or Orai1 levels in lipid nanodomains isolated from BC cells. Analyses of tissue microarray from CRC patients showed higher SigmaR1 expression levels in cancer samples and a correlation with tumor grade. Moreover, the exploration of a cohort of 4937 BC patients indicated that high expression of SigmaR1 and Orai1 channels was significantly correlated to a lower overall survival. As the SK3/Orai1 tandem drives invasive process in CRC and bone metastasis progression in BC, our results may inaugurate innovative therapeutic approaches targeting SigmaR1 to control the remodeling of Ca2+ homeostasis in epithelial cancers.
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Affiliation(s)
- M Gueguinou
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - D Crottès
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - A Chantôme
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | | | | | - L Clarysse
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - A Girault
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - Y Fourbon
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - P Jézéquel
- Unité de Bioinfomique, Institut de Cancérologie de L'Ouest - René Gauducheau, Centre de Recherche en Cancérologie, UMR-INSERM 892, St Herblain, France
| | - C Guérin-Charbonnel
- Unité de Bioinfomique, Institut de Cancérologie de L'Ouest - René Gauducheau, Centre de Recherche en Cancérologie, UMR-INSERM 892, St Herblain, France
| | - G Fromont
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
- Service d'Anatomie Pathologique, Hopital Bretonneau, CHRU Tours, Tours, France
| | - P Martin
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - B Pellissier
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - R Schiappa
- Unité d'Epidémiologie et Biostatistiques (UEB), Centre Antoine Lacassagne, Nice, France
| | - E Chamorey
- Unité d'Epidémiologie et Biostatistiques (UEB), Centre Antoine Lacassagne, Nice, France
| | - O Mignen
- Department of Pathology, Inserm U1078, Brest University Hospital, Brest, France
| | - A Uguen
- Department of Pathology, Inserm U1078, Brest University Hospital, Brest, France
| | - F Borgese
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - C Vandier
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - O Soriani
- Université Côte d'Azur, CNRS, Inserm, iBV, France
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23
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Ivanova AA, Maksimov VN, Ivanoshchuk DE, Orlov PS, Novoselov VP, Savchenko SV, Voevoda MI. Association of Polymorphism in SCN5A, GJA5, and KCNN3 Gene with Sudden Cardiac Death. Bull Exp Biol Med 2017; 163:73-77. [PMID: 28577096 DOI: 10.1007/s10517-017-3741-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Indexed: 11/29/2022]
Abstract
We studied association of single-nucleotide SCN5A (rs1805124), GJA5 (rs35594137), and KCNN3 (rs13376333) polymorphisms and sudden cardiac death. Humans died suddenly from cardiac causes (N=379) and unrelated sex- and age-matched control subjects were genotyped. No significant intergroup differences were found in the frequency of rs1805124 and rs13376333 genotypes and alleles. In women under 50 years, enhanced risk of sudden cardiac death was associated with rs35594137 GG genotype (OR=3.6; 95%CI=1.2-10.4; p=0.022), while in older women it was associated with rs35594137 AA genotype (OR=3.0; 95%CI=2.3-3.9; p=0.041). In women under 50 years, GA rs35594137 genotype was associated with a protective effect against sudden cardiac death (OR=0.3; 95%CI=0.1-0.8; p=0.036). Thus, GJA5 gene rs35594137 polymorphism is significantly associated with sudden cardiac death in the examined group.
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Affiliation(s)
- A A Ivanova
- Research Institute of Therapy and Preventive Medicine, Novosibirsk, Russia.
| | - V N Maksimov
- Research Institute of Therapy and Preventive Medicine, Novosibirsk, Russia
- Novosibirsk State Medical University, Ministry of Health of the Russian Federation, Novosibirsk, Russia
| | - D E Ivanoshchuk
- Research Institute of Therapy and Preventive Medicine, Novosibirsk, Russia
- Federal Research Centre Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
- Novosibirsk National Research State University, Novosibirsk, Russia
| | - P S Orlov
- Research Institute of Therapy and Preventive Medicine, Novosibirsk, Russia
- Federal Research Centre Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
- Novosibirsk National Research State University, Novosibirsk, Russia
| | - V P Novoselov
- Novosibirsk State Medical University, Ministry of Health of the Russian Federation, Novosibirsk, Russia
- Novosibirsk Regional Clinical Bureau of Forensic Medicine, Novosibirsk, Russia
| | - S V Savchenko
- Novosibirsk State Medical University, Ministry of Health of the Russian Federation, Novosibirsk, Russia
- Novosibirsk Regional Clinical Bureau of Forensic Medicine, Novosibirsk, Russia
| | - M I Voevoda
- Research Institute of Therapy and Preventive Medicine, Novosibirsk, Russia
- Federal Research Centre Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, Russia
- Novosibirsk National Research State University, Novosibirsk, Russia
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24
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Hobbelt AH, Siland JE, Geelhoed B, Van Der Harst P, Hillege HL, Van Gelder IC, Rienstra M. Clinical, biomarker, and genetic predictors of specific types of atrial fibrillation in a community-based cohort: data of the PREVEND study. Europace 2017; 19:226-232. [PMID: 28175276 PMCID: PMC5834149 DOI: 10.1093/europace/euw016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 01/18/2016] [Indexed: 11/14/2022] Open
Abstract
Aims Atrial fibrillation (AF) may present variously in time, and AF may progress from self-terminating to non-self-terminating AF, and is associated with impaired prognosis. However, predictors of AF types are largely unexplored. We investigate the clinical, biomarker, and genetic predictors of development of specific types of AF in a community-based cohort. Methods We included 8042 individuals (319 with incident AF) of the PREVEND study. Types of AF were compared, and multivariate multinomial regression analysis determined associations with specific types of AF. Results Mean age was 48.5 ± 12.4 years and 50% were men. The types of incident AF were ascertained based on electrocardiograms; 103(32%) were classified as AF without 2-year recurrence, 158(50%) as self-terminating AF, and 58(18%) as non-self-terminating AF. With multivariate multinomial logistic regression analysis, advancing age (P< 0.001 for all three types) was associated with all AF types, male sex was associated with AF without 2-year recurrence and self-terminating AF (P= 0.031 and P= 0.008, respectively). Increasing body mass index and MR-proANP were associated with both self-terminating (P= 0.009 and P< 0.001) and non-self-terminating AF (P= 0.003 and P< 0.001). The only predictor associated with solely self-terminating AF is prescribed anti-hypertensive treatment (P= 0.019). The following predictors were associated with non-self-terminating AF; lower heart rate (P= 0.018), lipid-lowering treatment prescribed (P= 0.009), and eGFR <60 mL/min/1.73 m2 (P= 0.006). Three known AF-genetic variants (rs6666258, rs6817105, and rs10821415) were associated with self-terminating AF. Conclusions We found clinical, biomarker and genetic predictors of specific types of incident AF in a community-based cohort. The genetic background seems to play a more important role than modifiable risk factors in self-terminating AF.
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Affiliation(s)
- Anne H. Hobbelt
- Department of Cardiology, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Joylene E. Siland
- Department of Cardiology, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Bastiaan Geelhoed
- Department of Cardiology, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Pim Van Der Harst
- Department of Cardiology, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Hans L. Hillege
- Department of Cardiology, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Isabelle C. Van Gelder
- Department of Cardiology, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
| | - Michiel Rienstra
- Department of Cardiology, University of Groningen, University Medical Center Groningen, PO Box 30.001, 9700 RB Groningen, The Netherlands
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Seki T, Goto K, Kiyohara K, Kansui Y, Murakami N, Haga Y, Ohtsubo T, Matsumura K, Kitazono T. Downregulation of Endothelial Transient Receptor Potential Vanilloid Type 4 Channel and Small-Conductance of Ca2+-Activated K+ Channels Underpins Impaired Endothelium-Dependent Hyperpolarization in Hypertension. Hypertension 2016; 69:143-153. [PMID: 27872234 DOI: 10.1161/hypertensionaha.116.07110] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 09/01/2016] [Accepted: 10/31/2016] [Indexed: 01/24/2023]
Abstract
Endothelium-dependent hyperpolarization (EDH)-mediated responses are impaired in hypertension, but the underlying mechanisms have not yet been determined. The activation of small- and intermediate-conductance of Ca2+-activated K+ channels (SKCa and IKCa) underpins EDH-mediated responses. It was recently reported that Ca2+ influx through endothelial transient receptor potential vanilloid type 4 channel (TRPV4) is a prerequisite for the activation of SKCa/IKCa in endothelial cells in specific beds. Here, we attempted to determine whether the impairment of EDH in hypertension is attributable to the dysfunction of TRPV4 and S/IKCa, using isolated superior mesenteric arteries of 20-week-old stroke-prone spontaneously hypertensive rats (SHRSP) and age-matched Wistar-Kyoto (WKY) rats. In the WKY arteries, EDH-mediated responses were reduced by a combination of SKCa/IKCa blockers (apamin plus TRAM-34; 1-[(2-chlorophenyl)diphenylmethl]-1H-pyrazole) and by the blockade of TRPV4 with the selective antagonist RN-1734 or HC-067047. In the SHRSP arteries, EDH-mediated hyperpolarization and relaxation were significantly impaired when compared with WKY. GSK1016790A, a selective TRPV4 activator, evoked robust hyperpolarization and relaxation in WKY arteries. In contrast, in SHRSP arteries, the GSK1016790A-evoked hyperpolarization was small and relaxation was absent. Hyperpolarization and relaxation to cyclohexyl-[2-(3,5-dimethyl-pyrazol-1-yl)-6-methyl-pyrimidin-4-yl]-amine, a selective SKCa activator, were marginally decreased in SHRSP arteries compared with WKY arteries. The expression of endothelial TRPV4 and SKCa protein was significantly decreased in the SHRSP mesenteric arteries compared with those of WKY, whereas function and expression of IKCa were preserved in SHRSP arteries. These findings suggest that EDH-mediated responses are impaired in superior mesenteric arteries of SHRSP because of a reduction in both TRPV4 and SKCa input to EDH.
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Affiliation(s)
- Takunori Seki
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kenichi Goto
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
| | - Kanako Kiyohara
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yasuo Kansui
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Noboru Murakami
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Yoshie Haga
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshio Ohtsubo
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Kiyoshi Matsumura
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Takanari Kitazono
- From the Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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26
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Yu CC, Chia-Ti T, Chen PL, Wu CK, Chiu FC, Chiang FT, Chen PS, Chen CL, Lin LY, Juang JM, Ho LT, Lai LP, Yang WS, Lin JL. KCNN2 polymorphisms and cardiac tachyarrhythmias. Medicine (Baltimore) 2016; 95:e4312. [PMID: 27442679 PMCID: PMC5265796 DOI: 10.1097/md.0000000000004312] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Potassium calcium-activated channel subfamily N member 2 (KCNN2) encodes an integral membrane protein that forms small-conductance calcium-activated potassium (SK) channels. Recent studies in animal models show that SK channels are important in atrial and ventricular repolarization and arrhythmogenesis. However, the importance of SK channels in human arrhythmia remains unclear. The purpose of the present study was to test the association between genetic polymorphism of the SK2 channel and the occurrence of cardiac tachyarrhythmias in humans. We enrolled 327 Han Chinese, including 72 with clinically significant ventricular tachyarrhythmias (VTa) who had a history of aborted sudden cardiac death (SCD) or unexplained syncope, 98 with a history of atrial fibrillation (AF), and 144 normal controls. We genotyped 12 representative tag single nucleotide polymorphisms (SNPs) across a 141-kb genetic region containing the KCNN2 gene; these captured the full haplotype information. The rs13184658 and rs10076582 variants of KCNN2 were associated with VTa in both the additive and dominant models (odds ratio [OR] 2.89, 95% confidence interval [CI] = 1.505-5.545, P = 0.001; and OR 2.55, 95% CI = 1.428-4.566, P = 0.002, respectively). After adjustment for potential risk factors, the association remained significant. The population attributable risks of these 2 variants of VTa were 17.3% and 10.6%, respectively. One variant (rs13184658) showed weak but significant association with AF in a dominant model (OR 1.91, CI = 1.025-3.570], P = 0.042). There was a significant association between the KCNN2 variants and clinically significant VTa. These findings suggest an association between KCNN2 and VTa; it also appears that KCNN2 variants may be adjunctive markers for risk stratification in patients susceptible to SCD.
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Affiliation(s)
- Chih-Chieh Yu
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
| | - Tsai Chia-Ti
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
| | - Pei-Lung Chen
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
- Department of Medical Genetics, National Taiwan University Hospital
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine
- Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei
| | - Cho-Kai Wu
- Department of Internal Medicine, National Taiwan University Hospital
| | - Fu-Chun Chiu
- Department of Internal Medicine, National Taiwan University Hospital, Yun-Lin Branch, Yun-Lin, Taiwan
| | - Fu-Tien Chiang
- Department of Internal Medicine, National Taiwan University Hospital
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Chi-Ling Chen
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
- Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Lian-Yu Lin
- Department of Internal Medicine, National Taiwan University Hospital
| | - Jyh-Ming Juang
- Department of Internal Medicine, National Taiwan University Hospital
| | - Li-Ting Ho
- Department of Internal Medicine, National Taiwan University Hospital
| | - Ling-Ping Lai
- Department of Internal Medicine, National Taiwan University Hospital
| | - Wei-Shiung Yang
- Department of Internal Medicine, National Taiwan University Hospital
- Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University
- Graduate Institute of Medical Genomics and Proteomics, College of Medicine
- Research Center for Developmental Biology and Regenerative Medicine, National Taiwan University, Taipei
- Correspondence: Jiunn-Lee Lin, Wei-Shiung Yang, Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung San South Road, Taipei City 100, Taiwan (R.O.C.) (e-mail: , )
| | - Jiunn-Lee Lin
- Department of Internal Medicine, National Taiwan University Hospital
- Correspondence: Jiunn-Lee Lin, Wei-Shiung Yang, Department of Internal Medicine, National Taiwan University Hospital, No. 7, Chung San South Road, Taipei City 100, Taiwan (R.O.C.) (e-mail: , )
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Martin S, Lazzarini M, Dullin C, Balakrishnan S, Gomes FV, Ninkovic M, El Hady A, Pardo LA, Stühmer W, Del-Bel E. SK3 Channel Overexpression in Mice Causes Hippocampal Shrinkage Associated with Cognitive Impairments. Mol Neurobiol 2016; 54:1078-1091. [PMID: 26803493 PMCID: PMC5310555 DOI: 10.1007/s12035-015-9680-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 12/23/2015] [Indexed: 12/11/2022]
Abstract
The dysfunction of the small-conductance calcium-activated K+ channel SK3 has been described as one of the factors responsible for the progress of psychoneurological diseases, but the molecular basis of this is largely unknown. This report reveals through use of immunohistochemistry and computational tomography that long-term increased expression of the SK3 small-conductance calcium-activated potassium channel (SK3-T/T) in mice induces a notable bilateral reduction of the hippocampal area (more than 50 %). Histological analysis showed that SK3-T/T mice have cellular disarrangements and neuron discontinuities in the hippocampal formation CA1 and CA3 neuronal layer. SK3 overexpression resulted in cognitive loss as determined by the object recognition test. Electrophysiological examination of hippocampal slices revealed that SK3 channel overexpression induced deficiency of long-term potentiation in hippocampal microcircuits. In association with these results, there were changes at the mRNA levels of some genes involved in Alzheimer’s disease and/or linked to schizophrenia, epilepsy, and autism. Taken together, these features suggest that augmenting the function of SK3 ion channel in mice may present a unique opportunity to investigate the neural basis of central nervous system dysfunctions associated with schizophrenia, Alzheimer’s disease, or other neuropsychiatric/neurodegenerative disorders in this model system. As a more detailed understanding of the role of the SK3 channel in brain disorders is limited by the lack of specific SK3 antagonists and agonists, the results observed in this study are of significant interest; they suggest a new approach for the development of neuroprotective strategies in neuropsychiatric/neurodegenerative diseases with SK3 representing a potential drug target.
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Affiliation(s)
- Sabine Martin
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Marcio Lazzarini
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany
| | - Christian Dullin
- Department of Diagnostic and Interventional Radiology, Georg-August University Medical Center, 37075, Göttingen, Germany
| | - Saju Balakrishnan
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
- Department of Neuro- and Sensory Physiology, Georg-August University Medical Center, 37073, Göttingen, Germany
| | - Felipe V Gomes
- Department of Pharmacology, Medical School of Ribeirão Preto, University of São Paulo, 14040-900, Ribeirão Preto, Brazil
| | - Milena Ninkovic
- Department of Neurosurgery, Georg-August University Medical Center, 37075, Göttingen, Germany
| | - Ahmed El Hady
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany
- Bernstein Focus for Neurotechnology and Bernstein Center for Computational Neuroscience, Göttingen, Germany
- Theoretical Neurophysics, Department of Non-linear Dynamics, Max Planck Institute for Dynamics and Self-Organization, 37077, Göttingen, Germany
- The Interdisciplinary Collaborative Research Center 889 "Cellular Mechanisms of Sensory Processing", Göttingen, Germany
| | - Luis A Pardo
- Oncophysiology Group, Max Planck Institute of Experimental Medicine, 37075, Göttingen, Germany
| | - Walter Stühmer
- Department of Molecular Biology of Neuronal Signals, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3, 37075, Göttingen, Germany.
- Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany.
- Bernstein Focus for Neurotechnology and Bernstein Center for Computational Neuroscience, Göttingen, Germany.
| | - Elaine Del-Bel
- Department of Morphology, Physiology and Pathology, CNPQ Research 1B (Biophysics, Biochemistry, Pharmacology and Neuroscience), University of São Paulo Dental School of Ribeirão Preto, Avenida do Café 3400, 14040-904, Ribeirão Preto, Brazil.
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28
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Ortega A, Tarazón E, Roselló-Lletí E, Gil-Cayuela C, Lago F, González-Juanatey JR, Cinca J, Jorge E, Martínez-Dolz L, Portolés M, Rivera M. Patients with Dilated Cardiomyopathy and Sustained Monomorphic Ventricular Tachycardia Show Up-Regulation of KCNN3 and KCNJ2 Genes and CACNG8-Linked Left Ventricular Dysfunction. PLoS One 2015; 10:e0145518. [PMID: 26710323 PMCID: PMC4692400 DOI: 10.1371/journal.pone.0145518] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 12/05/2015] [Indexed: 01/26/2023] Open
Abstract
AIMS Disruptions in cardiac ion channels have shown to influence the impaired cardiac contraction in heart failure. We sought to determine the altered gene expression profile of this category in dilated cardiomyopathy (DCM) patients and relate the altered gene expression with the clinical signs present in our patients, such as ventricular dysfunction and sustained monomorphic ventricular tachycardia (SMVT). METHODS AND RESULTS Left ventricular (LV) tissue samples were used in RNA-sequencing technique to elucidate the transcriptomic changes of 13 DCM patients compared to controls (n = 10). We analyzed the differential gene expression of cardiac ion channels, and we found a total of 34 altered genes. We found that the calcium channel CACNG8 mRNA and protein levels were down-regulated and highly and inversely related with LV ejection fraction (LVEF) (r = -0.78, P<0.01). Furthermore, the potassium channels KCNN3 and KCNJ2 mRNA and protein levels were up-regulated and showed also a significant and inverse correlation with LVEF (r = -0.61, P<0.05; r = -0.60, P<0.05) in patients with SMVT. CONCLUSION A broad set of deregulated genes have been identified by RNA-sequencing technique. The relationship of CACNG8, KCNN3 and KCNJ2 with LVEF, and the up-regulation of KCNN3 and KCNJ2 in all patients with SMVT, irrespective of CACNG8 expression, suggest a significant role for these three ion flux related genes in the LV dysfunction present in this cardiomyopathy and an important relationship between KCNN3 and KCNJ2 up-regulation and the presence of SMVT.
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Affiliation(s)
- Ana Ortega
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Estefanía Tarazón
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Esther Roselló-Lletí
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Carolina Gil-Cayuela
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Francisca Lago
- Cellular and Molecular Cardiology Research Unit, Department of Cardiology and Institute of Biomedical Research, University Clinical Hospital, Santiago de Compostela, Spain
| | - Jose-Ramón González-Juanatey
- Cellular and Molecular Cardiology Research Unit, Department of Cardiology and Institute of Biomedical Research, University Clinical Hospital, Santiago de Compostela, Spain
| | - Juan Cinca
- Cardiology Service of Santa Creu i Sant Pau Hospital, Barcelona, Spain
| | - Esther Jorge
- Cardiology Service of Santa Creu i Sant Pau Hospital, Barcelona, Spain
| | - Luis Martínez-Dolz
- Heart Failure and Transplantation Unit, Cardiology Department, La Fe University Hospital, Valencia, Spain
| | - Manuel Portolés
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
| | - Miguel Rivera
- Cardiocirculatory Unit, Health Research Institute of La Fe University Hospital (IIS La Fe), Valencia, Spain
- * E-mail:
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29
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Tsai CF, Hsieh TH, Lee JN, Hsu CY, Wang YC, Kuo KK, Wu HL, Chiu CC, Tsai EM, Kuo PL. Curcumin Suppresses Phthalate-Induced Metastasis and the Proportion of Cancer Stem Cell (CSC)-like Cells via the Inhibition of AhR/ERK/SK1 Signaling in Hepatocellular Carcinoma. J Agric Food Chem 2015; 63:10388-10398. [PMID: 26585812 DOI: 10.1021/acs.jafc.5b04415] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Recent evidence indicating that phthalates promote cancer development, including cell proliferation, migration, and invasion, has raised public health concerns. Here, we show that bis(2-ethylhexyl) phthalate promotes the migration, invasion, and epithelial-mesenchymal transition of hepatocellular carcinoma cells. In addition, bis(2-ethylhexyl) phthalate increased the proportion of cancer stem cell (CSC)-like cells and stemness maintenance in vitro as well as tumor growth and metastasis in vivo. The various activities of curcumin, including anticancer, anti-inflammation, antioxidation, and immunomodulation, have been investigated extensively. Curcumin suppressed phthalate-induced cell migration, invasion, and epithelial-mesenchymal transition, decreased the proportion of CSC-like cells in hepatocellular carcinoma cell lines in vitro, and inhibited tumor growth and metastasis in vivo. We also reveal that curcumin suppressed phthalate-induced migration, invasion, and CSC-like cell maintenance through inhibition of the aryl hydrocarbon receptor/ERK/SK1/S1P3 signaling pathway. Our results suggest that curcumin may be a potential antidote for phthalate-induced cancer progression.
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Affiliation(s)
- Cheng-Fang Tsai
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University , Kaohsiung City 807, Taiwan
| | - Tsung-Hua Hsieh
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University , Kaohsiung City 807, Taiwan
| | - Jau-Nan Lee
- Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital , Kaohsiung City 807, Taiwan
| | - Chia-Yi Hsu
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University , Kaohsiung City 807, Taiwan
| | - Yu-Chih Wang
- Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital , Kaohsiung City 807, Taiwan
| | - Kung-Kai Kuo
- Division of Hepatobiliary Pancreatic Surgery, Department of Surgery, Kaohsiung Medical University Hospital , Kaohsiung 807, Taiwan
| | - Hua-Lin Wu
- Department of Biochemistry and Molecular Biology, National Cheng Kung University , Tainan 701, Taiwan
| | - Chien-Chih Chiu
- Department of Biotechnology, Kaohsiung Medical University , Kaohsiung 807, Taiwan
| | - Eing-Mei Tsai
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University , Kaohsiung City 807, Taiwan
- Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital , Kaohsiung City 807, Taiwan
| | - Po-Lin Kuo
- Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University , Kaohsiung 807, Taiwan
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Choi EK, Park JH, Lee JY, Nam CM, Hwang MK, Uhm JS, Joung B, Ko YG, Lee MH, Lubitz SA, Ellinor PT, Pak HN. Korean Atrial Fibrillation (AF) Network: Genetic Variants for AF Do Not Predict Ablation Success. J Am Heart Assoc 2015; 4:e002046. [PMID: 26272656 PMCID: PMC4599462 DOI: 10.1161/jaha.115.002046] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/16/2015] [Indexed: 11/25/2022]
Abstract
BACKGROUND Genomewide association studies have identified several loci associated with atrial fibrillation (AF) and have been reportedly associated with response to catheter ablation for AF in patients of European ancestry; however, associations between top susceptibility loci and AF recurrence after ablation have not been examined in Asian populations. We examined whether the top single nucleotide polymorphisms (SNPs) at chromosomes 4q25 (PITX2), 16q22 (ZFHX3), and 1q21 (KCNN3) were associated with AF in a Korean population and whether these SNPs were associated with clinical outcomes after catheter ablation for AF. METHODS AND RESULTS We determined the association between 4 SNPs and AF in 1068 AF patients who underwent catheter ablation (74.6% male, aged 57.5±10.9 years, 67.9% paroxysmal AF) and 1068 age- and sex-matched controls. The SNPs at the PITX2 and ZFHX3 loci, but not the KCNN3 locus, were significantly associated with AF (PITX2/rs6843082_G: odds ratio 3.41, 95% CI 2.55 to 4.55, P=1.32×10(-16); PITX2/rs2200733_T: odds ratio 2.05, 95% CI 1.66 to 2.53, P=2.20×10(-11); ZFHX3/rs2106261_A: odds ratio 2.33, 95% CI 1.87 to 2.91, P=3.75×10(-14); KCNN3/rs13376333_T: odds ratio 1.74, 95% CI 0.93 to 3.25, P=0.085). Among those patients who underwent catheter ablation for AF, none of the top AF-associated SNPs were associated with long-term clinical recurrence of AF after catheter ablation. CONCLUSIONS SNPs at the PITX2 and ZFHX3 loci were strongly associated with AF in Korean patients. In contrast to prior reports, none of the 4 top AF-susceptibility SNPs predicted clinical recurrence after catheter ablation.
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Affiliation(s)
- Eue-Keun Choi
- Department of Internal Medicine, Seoul National University HospitalSeoul, Korea
| | - Jae Hyung Park
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Ji-Young Lee
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Chung Mo Nam
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Min Ki Hwang
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Jae-Sun Uhm
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Boyoung Joung
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Young-Guk Ko
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Moon-Hyoung Lee
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
| | - Steven A Lubitz
- Cardiac Arrhythmia Service and Cardiovascular Research Center, Massachusetts General HospitalBoston, MA
- Program in Medical and Population Genetics, The Broad Institute of Harvard and MITCambridge, MA
| | - Patrick T Ellinor
- Cardiac Arrhythmia Service and Cardiovascular Research Center, Massachusetts General HospitalBoston, MA
- Program in Medical and Population Genetics, The Broad Institute of Harvard and MITCambridge, MA
| | - Hui-Nam Pak
- Cardiovascular Genome Center, Yonsei University Health SystemSeoul, Korea
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Luo Z, Yan C, Zhang W, Shen X, Zheng W, Chen F, Cao X, Yang Y, Lin X, Wang Z, Huang M. Association between SNP rs13376333 and rs1131820 in the KCNN3 gene and atrial fibrillation in the Chinese Han population. Clin Chem Lab Med 2015; 52:1867-73. [PMID: 24978901 DOI: 10.1515/cclm-2014-0491] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 06/10/2014] [Indexed: 11/15/2022]
Abstract
BACKGROUND The small conductance calcium-activated potassium, subfamily N, member 3 (KCNN3) gene rs13376333 and rs1131820 have been shown to be strongly associated with lone atrial fibrillation (AF), while replication association studies between rs13376333 in KCNN3 gene and risk of AF showed conflicting results. The current study tried to validate the impact of SNP rs13376333 and rs1131820 of KCNN3 gene on the risk of AF in the Chinese Han population. METHODS A total of 889 AF patients and 1015 controls were enrolled. Two hundred and seventy-eight cases of AF were lone AF. KCNN3 gene SNP rs13376333 and rs1131820 were genotyped by allele-specific MALDI-TOF mass spectrometry. RESULTS The genotype distribution and allele frequency of rs13376333 polymorphism were not different between total AF patients and controls. However, the genotype distribution of rs13376333 polymorphism was significantly different between lone AF and control group (p<0.001); and T allele frequency was significantly higher in lone AF group than that in controls (7.6% vs 3.6%, p<0.001). Multivariable logistic regression analysis showed that T allele carriers of rs13376333 was significantly associated with lone AF (OR=2.31, 95% CI 1.41-3.78, p=0.001). No relationship between rs1131820 polymorphism and total AF or lone AF was found in this study. CONCLUSIONS KCNN3 rs13376333 polymorphism was associated with lone AF in the Chinese Han population and the T allele carriers may be an independent predictive factor for lone AF.
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Tsai CT, Hsieh CS, Chang SN, Chuang EY, Juang JMJ, Lin LY, Lai LP, Hwang JJ, Chiang FT, Lin JL. Next-generation sequencing of nine atrial fibrillation candidate genes identified novel de novo mutations in patients with extreme trait of atrial fibrillation. J Med Genet 2015; 52:28-36. [PMID: 25391453 DOI: 10.1136/jmedgenet-2014-102618] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. Genome-wide association studies (GWAS) have identified common variants in nine genomic regions associated with AF (KCNN3, PRRX1, PITX2, WNT8A, CAV1, C9orf3, SYNE2, HCN4 and ZFHX3 genes); however, the genetic variability of these risk variants does not explain the entire genetic susceptibility to AF. Rare variants missed by GWAS may also contribute to genetic risk of AF. METHODS We used an extreme trait design to sequence carefully selected probands with extreme phenotypes and their unaffected parents to identify rare de novo variants or mutations. Based on the hypothesis that common and rare variants may colocate in the same disease susceptibility gene, we used next-generation sequencing to sequence these nine published AF susceptibility genes identified by GWAS (a total of 179 exons) in 20 trios, 200 unrelated patients with AF and 200 non-AF controls. RESULTS We identified a novel mutation in the 5' untranslated region of the PITX2 gene, which localised in the transcriptionally active enhancer region. We also identified one missense exon mutation in KCNN3, two in ZFHX3 and one in SYNE2. None of these mutations were present in other unrelated patients with AF, healthy controls, unaffected parents and are thus novel and de novo (p<10(-4)). Functional study showed that the mutation in the 5' untranslated region of the PITX2 gene significantly downregulated PITX2 expression in atrial myocytes, either in basal condition or during rapid pacing. In silico analysis showed that the missense mutation in ZFHX3 results in damage of the ZFHX3 protein structure. CONCLUSIONS The genetic architecture of subjects with extreme phenotypes of AF is similar to that of rare or Mendelian diseases, and mutations may be the underlying cause.
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Affiliation(s)
- Chia-Ti Tsai
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chia-Shan Hsieh
- Genome and Systems Biology Degree Program, Department of Life Science, National Taiwan University, Taipei, Taiwan Bioinformatics and Biostatistics Core, Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan
| | - Sheng-Nan Chang
- Department of Internal Medicine, National Taiwan University Hospital Yun-Lin Branch, Yun-Lin, Taiwan
| | - Eric Y Chuang
- Genome and Systems Biology Degree Program, Department of Life Science, National Taiwan University, Taipei, Taiwan Bioinformatics and Biostatistics Core, Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan
| | - Jyh-Ming Jimmy Juang
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Lian-Yu Lin
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Ling-Ping Lai
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Juey-Jen Hwang
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Fu-Tien Chiang
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan Department of Laboratory Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
| | - Jiunn-Lee Lin
- Division of Cardiology, Department of Internal Medicine, National Taiwan University College of Medicine and Hospital, Taipei, Taiwan
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Climent B, Moreno L, Martínez P, Contreras C, Sánchez A, Pérez-Vizcaíno F, García-Sacristán A, Rivera L, Prieto D. Upregulation of SK3 and IK1 channels contributes to the enhanced endothelial calcium signaling and the preserved coronary relaxation in obese Zucker rats. PLoS One 2014; 9:e109432. [PMID: 25302606 PMCID: PMC4193814 DOI: 10.1371/journal.pone.0109432] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/01/2014] [Indexed: 12/19/2022] Open
Abstract
Background and Aims Endothelial small- and intermediate-conductance KCa channels, SK3 and IK1, are key mediators in the endothelium-derived hyperpolarization and relaxation of vascular smooth muscle and also in the modulation of endothelial Ca2+ signaling and nitric oxide (NO) release. Obesity is associated with endothelial dysfunction and impaired relaxation, although how obesity influences endothelial SK3/IK1 function is unclear. Therefore we assessed whether the role of these channels in the coronary circulation is altered in obese animals. Methods and Results In coronary arteries mounted in microvascular myographs, selective blockade of SK3/IK1 channels unmasked an increased contribution of these channels to the ACh- and to the exogenous NO- induced relaxations in arteries of Obese Zucker Rats (OZR) compared to Lean Zucker Rats (LZR). Relaxant responses induced by the SK3/IK1 channel activator NS309 were enhanced in OZR and NO- endothelium-dependent in LZR, whereas an additional endothelium-independent relaxant component was found in OZR. Fura2-AM fluorescence revealed a larger ACh-induced intracellular Ca2+ mobilization in the endothelium of coronary arteries from OZR, which was inhibited by blockade of SK3/IK1 channels in both LZR and OZR. Western blot analysis showed an increased expression of SK3/IK1 channels in coronary arteries of OZR and immunohistochemistry suggested that it takes place predominantly in the endothelial layer. Conclusions Obesity may induce activation of adaptive vascular mechanisms to preserve the dilator function in coronary arteries. Increased function and expression of SK3/IK1 channels by influencing endothelial Ca2+ dynamics might contribute to the unaltered endothelium-dependent coronary relaxation in the early stages of obesity.
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Affiliation(s)
- Belén Climent
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
- * E-mail: (BC); (DP)
| | - Laura Moreno
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense, Madrid, Spain
| | - Pilar Martínez
- Departamento de Anatomía y Anatomía Patológica Comparadas, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain
| | - Cristina Contreras
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Ana Sánchez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | | | | | - Luis Rivera
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
- * E-mail: (BC); (DP)
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Lu YC, Yang J, Ding GL, Shi S, Zhang D, Jin L, Pan JX, Lin XH, Zhu YM, Sheng JZ, Huang HF. Small-conductance, calcium-activated potassium channel 3 (SK3) is a modulator of endometrial remodeling during endometrial growth. J Clin Endocrinol Metab 2014; 99:3800-10. [PMID: 24978672 DOI: 10.1210/jc.2013-3389] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND Small-conductance, Ca(2+)-activated K(+) channel 3 (SK3) has been shown to be expressed in porcine endometrium. However, the roles of SK3 in human endometrium during the menstrual cycle and early pregnancy are unknown. OBJECTIVE The objective of the study was to investigate the expression and function of SK3 in human endometrium and the mechanism involved. METHODS We determined the expression of SK3 in human endometrium by RT-PCR, Western blotting, and immunofluorescence. Using electrophysiological and fluorescent imaging techniques, we investigated the effects of SK3 on the membrane potential and the concentrations of cytosolic calcium, respectively. The effects of SK3 on endometrial thickness and pregnancy outcome were also investigated. Knockdown of endometrial SK3 was used to examine the effects of SK3 on cell migration, cytoskeleton formation, and calcium concentration in the cytosol. RESULTS SK3 channels are present in human endometrium. In vivo experimental and clinical data demonstrated that the reduced expression of SK3 was associated with a thin endometrium and unsuccessful pregnancy outcomes. Knockdown of human endometrial SK3 attenuated the rise in cytosolic calcium and membrane hyperpolarization induced by thapsigargin, a Ca(2+)-ATPase inhibitor, cell migration, and F-actin assembly. Knockdown of endometrial SK3 in mice also resulted in a thin endometrium and unsuccessful pregnancy outcome. CONCLUSIONS These observations demonstrate that SK3 channels are expressed in human endometrial cells. Reduced SK3 expression attenuates endometrial cell migration and is associated with unsuccessful pregnancy outcomes.
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Affiliation(s)
- Yong-Chao Lu
- The Key Laboratory of Reproductive Genetics (Y.-C.L., J.Y., G.-L.D., S.S., D.Z., L.J., J.-X.P., X.-H.L., Y.-M.Z., J.-Z.S., H.-F.H.), Ministry of Education (Zhejiang University), Department of Reproductive Endocrinology (Y.-C.L., J.Y., G.-L.D., D.Z., L.J., J.-X.P., X.-H.L., Y.-M.Z., H.-F.H.), Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310006, China; Department of Pathology and Pathophysiology (S.S., J.-Z.S.), School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China; and International Peace Maternity and Child Health Hospital (H.-F.H.), Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
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Siddiqui T, Lively S, Ferreira R, Wong R, Schlichter LC. Expression and contributions of TRPM7 and KCa2.3/SK3 channels to the increased migration and invasion of microglia in anti-inflammatory activation states. PLoS One 2014; 9:e106087. [PMID: 25148577 PMCID: PMC4141841 DOI: 10.1371/journal.pone.0106087] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 07/31/2014] [Indexed: 01/17/2023] Open
Abstract
Microglia rapidly respond to CNS injury and disease and can assume a spectrum of activation states. While changes in gene expression and production of inflammatory mediators have been extensively described after classical (LPS-induced) and alternative (IL4-induced) microglial activation, less is known about acquired de-activation in response to IL10. It is important to understand how microglial activation states affect their migration and invasion; crucial functions after injury and in the developing CNS. We reported that LPS-treated rat microglia migrate very poorly, while IL4-treated cells migrate and invade much better. Having discovered that the lamellum of migrating microglia contains a large ring of podosomes – microscopic structures that are thought to mediate adhesion, migration and invasion – we hypothesized that IL4 and IL10 would differentially affect podosome expression, gene induction, migration and invasion. Further, based on the enrichment of the KCa2.3/SK3 Ca2+-activated potassium channel in microglial podosomes, we predicted that it regulates migration and invasion. We found both similarities and differences in gene induction by IL4 and IL10 and, while both cytokines increased migration and invasion, only IL10 affected podosome expression. KCa2.3 currents were recorded in microglia under all three activation conditions and KCNN3 (KCa2.3) expression was similar. Surprisingly then, of three KCa2.3 inhibitors (apamin, tamapin, NS8593), only NS8593 abrogated the increased migration and invasion of IL4 and IL10-treated microglia (and invasion of unstimulated microglia). This discrepancy was explained by the observed block of TRPM7 currents in microglia by NS8593, which occurred under all three activation conditions. A similar inhibition of both migration and invasion was seen with a TRPM7 inhibitor (AA-861) that does not block KCa2.3 channels. Thus, we conclude that TRPM7 (not KCa2.3) contributes to the enhanced ability of microglia to migrate and invade when in anti-inflammatory states. This will be an important consideration in developing TRPM7 inhibitors for treating CNS injury.
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Affiliation(s)
- Tamjeed Siddiqui
- Toronto Western Research Institute, Genes and Development Division, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Starlee Lively
- Toronto Western Research Institute, Genes and Development Division, University Health Network, Toronto, Ontario, Canada
| | - Roger Ferreira
- Toronto Western Research Institute, Genes and Development Division, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Raymond Wong
- Toronto Western Research Institute, Genes and Development Division, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Lyanne C. Schlichter
- Toronto Western Research Institute, Genes and Development Division, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Wandall-Frostholm C, Skaarup LM, Sadda V, Nielsen G, Hedegaard ER, Mogensen S, Köhler R, Simonsen U. Pulmonary hypertension in wild type mice and animals with genetic deficit in KCa2.3 and KCa3.1 channels. PLoS One 2014; 9:e97687. [PMID: 24858807 PMCID: PMC4032241 DOI: 10.1371/journal.pone.0097687] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 04/22/2014] [Indexed: 11/18/2022] Open
Abstract
Objective In vascular biology, endothelial KCa2.3 and KCa3.1 channels contribute to arterial blood pressure regulation by producing membrane hyperpolarization and smooth muscle relaxation. The role of KCa2.3 and KCa3.1 channels in the pulmonary circulation is not fully established. Using mice with genetically encoded deficit of KCa2.3 and KCa3.1 channels, this study investigated the effect of loss of the channels in hypoxia-induced pulmonary hypertension. Approach and Result Male wild type and KCa3.1−/−/KCa2.3T/T(+DOX) mice were exposed to chronic hypoxia for four weeks to induce pulmonary hypertension. The degree of pulmonary hypertension was evaluated by right ventricular pressure and assessment of right ventricular hypertrophy. Segments of pulmonary arteries were mounted in a wire myograph for functional studies and morphometric studies were performed on lung sections. Chronic hypoxia induced pulmonary hypertension, right ventricular hypertrophy, increased lung weight, and increased hematocrit levels in either genotype. The KCa3.1−/−/KCa2.3T/T(+DOX) mice developed structural alterations in the heart with increased right ventricular wall thickness as well as in pulmonary vessels with increased lumen size in partially- and fully-muscularized vessels and decreased wall area, not seen in wild type mice. Exposure to chronic hypoxia up-regulated the gene expression of the KCa2.3 channel by twofold in wild type mice and increased by 2.5-fold the relaxation evoked by the KCa2.3 and KCa3.1 channel activator NS309, whereas the acetylcholine-induced relaxation - sensitive to the combination of KCa2.3 and KCa3.1 channel blockers, apamin and charybdotoxin - was reduced by 2.5-fold in chronic hypoxic mice of either genotype. Conclusion Despite the deficits of the KCa2.3 and KCa3.1 channels failed to change hypoxia-induced pulmonary hypertension, the up-regulation of KCa2.3-gene expression and increased NS309-induced relaxation in wild-type mice point to a novel mechanism to counteract pulmonary hypertension and to a potential therapeutic utility of KCa2.3/KCa3.1 activators for the treatment of pulmonary hypertension.
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Affiliation(s)
| | | | - Veeranjaneyulu Sadda
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Institute for Molecular Medicine, Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | - Gorm Nielsen
- Institute for Molecular Medicine, Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
| | | | - Susie Mogensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ralf Köhler
- Institute for Molecular Medicine, Cardiovascular and Renal Research, University of Southern Denmark, Odense, Denmark
- Aragon Institute of Health Sciences I+CS and ARAID, Zaragoza, Spain
| | - Ulf Simonsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Berrout J, Mamenko M, Zaika OL, Chen L, Zang W, Pochynyuk O, O'Neil RG. Emerging role of the calcium-activated, small conductance, SK3 K+ channel in distal tubule function: regulation by TRPV4. PLoS One 2014; 9:e95149. [PMID: 24762817 PMCID: PMC3999037 DOI: 10.1371/journal.pone.0095149] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Accepted: 03/24/2014] [Indexed: 12/24/2022] Open
Abstract
The Ca2+-activated, maxi-K (BK) K+ channel, with low Ca2+-binding affinity, is expressed in the distal tubule of the nephron and contributes to flow-dependent K+ secretion. In the present study we demonstrate that the Ca2+-activated, SK3 (KCa2.3) K+ channel, with high Ca2+-binding affinity, is also expressed in the mouse kidney (RT-PCR, immunoblots). Immunohistochemical evaluations using tubule specific markers demonstrate significant expression of SK3 in the distal tubule and the entire collecting duct system, including the connecting tubule (CNT) and cortical collecting duct (CCD). In CNT and CCD, main sites for K+ secretion, the highest levels of expression were along the apical (luminal) cell membranes, including for both principal cells (PCs) and intercalated cells (ICs), posturing the channel for Ca2+-dependent K+ secretion. Fluorescent assessment of cell membrane potential in native, split-opened CCD, demonstrated that selective activation of the Ca2+-permeable TRPV4 channel, thereby inducing Ca2+ influx and elevating intracellular Ca2+ levels, activated both the SK3 channel and the BK channel leading to hyperpolarization of the cell membrane. The hyperpolarization response was decreased to a similar extent by either inhibition of SK3 channel with the selective SK antagonist, apamin, or by inhibition of the BK channel with the selective antagonist, iberiotoxin (IbTX). Addition of both inhibitors produced a further depolarization, indicating cooperative effects of the two channels on Vm. It is concluded that SK3 is functionally expressed in the distal nephron and collecting ducts where induction of TRPV4-mediated Ca2+ influx, leading to elevated intracellular Ca2+ levels, activates this high Ca2+-affinity K+ channel. Further, with sites of expression localized to the apical cell membrane, especially in the CNT and CCD, SK3 is poised to be a key pathway for Ca2+-dependent regulation of membrane potential and K+ secretion.
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Affiliation(s)
- Jonathan Berrout
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Mykola Mamenko
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Oleg L. Zaika
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Lihe Chen
- Department of Internal Medicine-Division of Renal Diseases and Hypertension, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Wenzheng Zang
- Department of Internal Medicine-Division of Renal Diseases and Hypertension, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Oleh Pochynyuk
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
| | - Roger G. O'Neil
- Department of Integrative Biology, The University of Texas Health Science Center Medical School, Houston, Texas, United States of America
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Fuchs PA, Lehar M, Hiel H. Ultrastructure of cisternal synapses on outer hair cells of the mouse cochlea. J Comp Neurol 2014; 522:717-29. [PMID: 24122766 PMCID: PMC4474150 DOI: 10.1002/cne.23478] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2013] [Revised: 09/20/2013] [Accepted: 09/20/2013] [Indexed: 12/31/2022]
Abstract
C (cisternal) synapses with a near membrane postsynaptic cistern are found on motor neurons and other central neurons, where their functional role is unknown. Similarly structured cisternal synapses mediate cholinergic inhibition of cochlear hair cells via α9α10-containing ionotropic receptors and associated calcium-activated (SK2) potassium channels, providing the opportunity to examine the ultrastructure of genetically altered cisternal synapses. Serial section electron microscopy was used to examine efferent synapses of outer hair cells (OHCs) in mice with diminished or enhanced cholinergic inhibition. The contact area of efferent terminals, the appositional area of the postsynaptic cistern, the distance of the cistern from the plasma membrane, and the average width of the cisternal lumen were recorded. The synaptic cisterns of wild-type OHCs were closely aligned (14-nm separation) with the hair cell membrane and coextensive with the micrometers-long synaptic terminals. The cisternal lumen averaged 18 nm so that the cisternal volume was approximately 30% larger than that of the cytoplasmic space between the cistern and the plasma membrane. Synaptic ultrastructure of α9L9'T knockin OHCs (acetylcholine receptor gain of function) were like those of wild-type littermates except that cisternal volumes were significantly larger. OHCs of SK2 knockout mice had few small efferent terminals. Synaptic cisterns were present, but smaller than those of wild-type littermates. Taken together, these data suggest that the cistern serves as a sink or buffer to isolate synaptic calcium signals.
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Affiliation(s)
- Paul Albert Fuchs
- Center for Hearing and Balance, Otolaryngology-Head and
Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
21205
- Center for Sensory Biology, Johns Hopkins University School
of Medicine, Baltimore, Maryland 21205
| | - Mohamed Lehar
- Center for Hearing and Balance, Otolaryngology-Head and
Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
21205
| | - Hakim Hiel
- Center for Hearing and Balance, Otolaryngology-Head and
Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
21205
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Fuchs PA. It takes two to tango. Channels (Austin) 2014; 8:167. [PMID: 25469408 PMCID: PMC5210167 DOI: 10.4161/chan.28999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 02/11/2014] [Indexed: 11/19/2022] Open
Affiliation(s)
- Paul Albert Fuchs
- The Center for Hearing and Balance; Department of Otolaryngology-Head and Neck Surgery; Center for Sensory Biology in the Institute for Basic Biomedical Science; Johns Hopkins University School of Medicine; Baltimore, MD USA
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Soden ME, Jones GL, Sanford CA, Chung AS, Güler AD, Chavkin C, Luján R, Zweifel LS. Disruption of dopamine neuron activity pattern regulation through selective expression of a human KCNN3 mutation. Neuron 2013; 80:997-1009. [PMID: 24206670 DOI: 10.1016/j.neuron.2013.07.044] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/25/2013] [Indexed: 11/19/2022]
Abstract
The calcium-activated small conductance potassium channel SK3 plays an essential role in the regulation of dopamine neuron activity patterns. Here we demonstrate that expression of a human disease-related SK3 mutation (hSK3Δ) in dopamine neurons of mice disrupts the balance between tonic and phasic dopamine neuron activity. Expression of hSK3Δ suppressed endogenous SK currents, reducing coupling between SK channels and NMDA receptors (NMDARs) and increasing permissiveness for burst firing. Consistent with enhanced excitability of dopamine neurons, hSK3Δ increased evoked calcium signals in dopamine neurons in vivo and potentiated evoked dopamine release. Specific expression of hSK3Δ led to deficits in attention and sensory gating and heightened sensitivity to a psychomimetic drug. Sensory-motor alterations and psychomimetic sensitivity were recapitulated in a mouse model of transient, reversible dopamine neuron activation. These results demonstrate the cell-autonomous effects of a human ion channel mutation on dopamine neuron physiology and the impact of activity pattern disruption on behavior.
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Affiliation(s)
- Marta E Soden
- Department of Pharmacology, University of Washington, Seattle, WA 98195, USA; Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
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Chotoo CK, Silverman GA, Devor DC, Luke CJ. A small conductance calcium-activated K+ channel in C. elegans, KCNL-2, plays a role in the regulation of the rate of egg-laying. PLoS One 2013; 8:e75869. [PMID: 24040423 PMCID: PMC3769271 DOI: 10.1371/journal.pone.0075869] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2012] [Accepted: 08/22/2013] [Indexed: 11/19/2022] Open
Abstract
In the nervous system of mice, small conductance calcium-activated potassium (SK) channels function to regulate neuronal excitability through the generation of a component of the medium afterhyperpolarization that follows action potentials. In humans, irregular action potential firing frequency underlies diseases such as ataxia, epilepsy, schizophrenia and Parkinson's disease. Due to the complexity of studying protein function in the mammalian nervous system, we sought to characterize an SK channel homologue, KCNL-2, in C. elegans, a genetically tractable system in which the lineage of individual neurons was mapped from their early developmental stages. Sequence analysis of the KCNL-2 protein reveals that the six transmembrane domains, the potassium-selective pore and the calmodulin binding domain are highly conserved with the mammalian homologues. We used widefield and confocal fluorescent imaging to show that a fusion construct of KCNL-2 with GFP in transgenic lines is expressed in the nervous system of C. elegans. We also show that a KCNL-2 null strain, kcnl-2(tm1885), demonstrates a mild egg-laying defective phenotype, a phenotype that is rescued in a KCNL-2-dependent manner. Conversely, we show that transgenic lines that overexpress KCNL-2 demonstrate a hyperactive egg-laying phenotype. In this study, we show that the vulva of transgenic hermaphrodites is highly innervated by neuronal processes and by the VC4 and VC5 neurons that express GFP-tagged KCNL-2. We propose that KCNL-2 functions in the nervous system of C. elegans to regulate the rate of egg-laying.
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Affiliation(s)
- Cavita K. Chotoo
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Gary A. Silverman
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Pediatrics, University of Pittsburgh, Children’s Hospital of Pittsburgh of UPMC and Magee-Women’s Hospital Research Institute, Pittsburgh, Pennsylvania, United States of America
| | - Daniel C. Devor
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (CJL); (DCD)
| | - Cliff J. Luke
- Department of Pediatrics, University of Pittsburgh, Children’s Hospital of Pittsburgh of UPMC and Magee-Women’s Hospital Research Institute, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (CJL); (DCD)
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Abstract
BACKGROUND Apamin sensitive potassium current (I KAS), carried by the type 2 small conductance Ca(2+)-activated potassium (SK2) channels, plays an important role in post-shock action potential duration (APD) shortening and recurrent spontaneous ventricular fibrillation (VF) in failing ventricles. OBJECTIVE To test the hypothesis that amiodarone inhibits I KAS in human embryonic kidney 293 (HEK-293) cells. METHODS We used the patch-clamp technique to study I KAS in HEK-293 cells transiently expressing human SK2 before and after amiodarone administration. RESULTS Amiodarone inhibited IKAS in a dose-dependent manner (IC50, 2.67 ± 0.25 µM with 1 µM intrapipette Ca(2+)). Maximal inhibition was observed with 50 µM amiodarone which inhibited 85.6 ± 3.1% of IKAS induced with 1 µM intrapipette Ca(2+) (n = 3). IKAS inhibition by amiodarone was not voltage-dependent, but was Ca(2+)-dependent: 30 µM amiodarone inhibited 81.5±1.9% of I KAS induced with 1 µM Ca(2+) (n = 4), and 16.4±4.9% with 250 nM Ca(2+) (n = 5). Desethylamiodarone, a major metabolite of amiodarone, also exerts voltage-independent but Ca(2+) dependent inhibition of I KAS. CONCLUSION Both amiodarone and desethylamiodarone inhibit I KAS at therapeutic concentrations. The inhibition is independent of time and voltage, but is dependent on the intracellular Ca(2+) concentration. SK2 current inhibition may in part underlie amiodarone's effects in preventing electrical storm in failing ventricles.
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Affiliation(s)
- Isik Turker
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Chih-Chieh Yu
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
- Division of Cardiology, Department of Medicine, National Taiwan University, Taipei, Taiwan
| | - Po-Cheng Chang
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Zhenhui Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Yoshiro Sohma
- Department of Pharmacology, Keio University School of Medicine, Shinjuku, Tokyo, Japan
| | - Shien-Fong Lin
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Peng-Sheng Chen
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
| | - Tomohiko Ai
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana
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Rada CC, Pierce SL, Nuno DW, Zimmerman K, Lamping KG, Bowdler NC, Weiss RM, England SK. Overexpression of the SK3 channel alters vascular remodeling during pregnancy, leading to fetal demise. Am J Physiol Endocrinol Metab 2012; 303:E825-31. [PMID: 22785240 PMCID: PMC3469615 DOI: 10.1152/ajpendo.00165.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The maternal cardiovascular system undergoes hemodynamic changes during pregnancy via angiogenesis and vasodilation to ensure adequate perfusion of the placenta. Improper vascularization at the maternal-fetal interface can cause pregnancy complications and poor fetal outcomes. Recent evidence indicates that small conductance Ca(2+)-activated K(+) channel subtype 3 (SK3) contributes to vascular remodeling during pregnancy, and we hypothesized that abnormal SK3 channel expression would alter the ability of the maternal cardiovascular system to adapt to pregnancy demands and lead to poor fetal outcomes. We investigated this hypothesis using transgenic Kcnn3(tm1Jpad)/Kcnn3(tm1Jpad) (SK3(T/T)) mice that overexpress the channel. Isolated pressurized uterine arteries from nonpregnant transgenic SK3(T/T) mice had larger basal diameters and decreased agonist-induced constriction than those from their wild-type counterparts; however, non-receptor-mediated depolarization remained intact. In addition to vascular changes, heart rates and ejection fraction were increased, whereas end systolic volume was reduced in SK3(T/T) mice compared with their wild-type littermates. Uterine sonography of the fetuses on pregnancy day 14 showed a significant decrease in fetal size in SK3(T/T) compared with wild-type mice; thus, SK3(T/T) mice displayed an intrauterine growth-restricted phenotype. The SK3(T/T) mice showed decreased placental thicknesses and higher incidence of fetal loss, losing over half of their complement of pups by midgestation. These results establish that the SK3 channel contributes to both maternal and fetal outcomes during pregnancy and point to the importance of SK3 channel regulation in maintaining a healthy pregnancy.
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Affiliation(s)
- Cara C Rada
- Department of Obstetrics and Gynecology, Washington Univ. School of Medicine, St. Louis, MO 63110, USA
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Tan XQ, Chen GL, Li T, Mao L, Inoue I, Yang Y, Zeng XR. [Construction and identification of the expression plasmid of SK2 (KCNN2) gene from human atrial myocytes with overlapping PCR]. Zhongguo Ying Yong Sheng Li Xue Za Zhi 2012; 28:381-384. [PMID: 23156743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE Small conductance calcium activated potassium channels type 2 (SK2) play a crucial role in atrial repolarization. It is difficult to acquire the full-length of its coded gene KCNN2 by RT-PCR with one step. We aim to get the full-length of KCNN2 gene and construct the plasmid by Overlapping PCR, and further more discuss the application of Overlapping PCR. METHODS Total RNA was extracted from human right atrial tissue and cDNA was acquired with reverse transcription. Overlapping PCR was conducted with three pairs of primers which were designed according to the sequence of KCNN2 (AY258141) gene. The expression plasmid of pIRES-hrGFP-SK2 was constructed by directed cloning with restriction enzyme site and identified by enzyme cutting and sequencing. RESULTS Three parts of PCR amplification were consistent with predicted size. The sequence of the plasmid was consistent with the gene-bank data except two sites, however, which were the same as gene in different tissues. CONCLUSION The expression plasmid pIRES-hrGFP-SK2 was constructed successfully. Overlapping PCR is a good choice for amplifying these genes with long size or low expression.
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Affiliation(s)
- Xiao-Qiu Tan
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Luzhou Medical College, Luzhou 646000, China
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Shen Q, Zhang J, Wang Y, Liu B, Li X, Zhao Q, Chen S, Ji J, Yang F, Wan C, Gao L, Xu Y, Feng G, He L, He G. No association between the KCNH1, KCNJ10 and KCNN3 genes and schizophrenia in the Han Chinese population. Neurosci Lett 2011; 487:61-5. [PMID: 20933057 DOI: 10.1016/j.neulet.2010.09.074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 09/15/2010] [Accepted: 09/29/2010] [Indexed: 11/30/2022]
Affiliation(s)
- Qi Shen
- Bio-X Center, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
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Abstract
Overexpression of the small-conductance calcium-activated K(+) channel 3 (SK3) in transgenic mice compromises parturition, suggesting that the SK3 channel plays a role in pregnancy. In wild-type mouse myometrium, expression of SK3 transcript and protein is significantly reduced during pregnancy, but the mechanism(s) responsible for this attenuation of channel expression is unknown. The promoter region of the SK3-encoding mouse KCNN3 gene contains two binding sites for specificity protein (Sp) transcription factors, two of which are expressed in the uterus: Sp1, which enhances gene transcription in response to estrogen; and Sp3, which competes for the same binding motif as Sp1 and can repress gene expression. We investigated the hypothesis that Sp1 and Sp3 regulate SK3 channel expression during pregnancy. In mouse myometrium, Sp1 expression was reduced during late gestation, whereas Sp3 expression levels were constant throughout pregnancy. Using a reporter system, we found that Sp1 overexpression resulted in a significant increase in SK3 promoter activation and that Sp3 cotransfection reduced promoter activation to basal levels. These findings indicate that Sp3 outcompetes Sp1 to decrease SK3 transcription. To determine whether high levels of estrogen in vivo can affect the regulation of SK3 protein levels by Sp factors, ovariectomized mice were implanted with a 17β-estradiol or placebo pellet for 3 wk; estrogen-treated mice had reduced uterine SK3 protein expression compared with placebo-treated counterparts. In human myometrial cells overexpressing Sp1, estrogen treatment stimulated expression of the SK3 transcript. Overall, our findings indicate that Sp1 and Sp3 compete to regulate SK3 channel expression during pregnancy in response to stimulation by estrogen.
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Affiliation(s)
- Stephanie L Pierce
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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Milkau M, Köhler R, de Wit C. Crucial importance of the endothelial K+ channel SK3 and connexin40 in arteriolar dilations during skeletal muscle contraction. FASEB J 2010; 24:3572-9. [PMID: 20427707 DOI: 10.1096/fj.10-158956] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Skeletal muscle activity requires substantial increases in blood flow, and the underlying vasodilation involves endothelial activity, but the contribution of the endothelium-dependent hyperpolarizing factor (EDHF) is only poorly defined. In EDHF signaling, endothelial hyperpolarization mediated by the Ca(2+)-activated K(+) channels SK3 and IK1 is a key step and also initiates gap junction-dependent conducted dilations. We assessed the role of SK3, IK1, and connexin40 (Cx40) in muscular contraction-induced dilations in the microcirculation in vivo. Hitherto, arterioles were observed in the electrically stimulated cremaster skeletal muscle of anesthetized mice lacking SK3, IK1, or Cx40 using intravital microscopy. Genetic deficiency of SK3, but not of IK1, strongly attenuated dilations to muscular contraction. Similarly, pharmacologic blockade of SK3 by the specific blocker UCL1684 impaired such dilations in wild-type and IK1-deficient mice. In contrast, IK1 was required for acetylcholine-induced dilations. Genetic deficiency of Cx40 also attenuated dilations induced by muscular contraction but not by acetylcholine. These data support the concept that endothelial hyperpolarization through activation of SK3 contributes to exercise hyperemia and the hyperpolarization ascends the vascular tree through gap junctions formed by Cx40 to orchestrate dilation. The differential impact of SK3- and IK1-deficiency on dilations to distinct stimuli suggests stimulus-dependent activation of these endothelial channels.
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Affiliation(s)
- Malte Milkau
- Institut für Physiologie, Universität zu Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany
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Rinaldo L, Hansel C. Ataxias and cerebellar dysfunction: involvement of synaptic plasticity deficits? Funct Neurol 2010; 25:135-139. [PMID: 21232209 PMCID: PMC3056151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Adaptive processes within cerebellar circuits, such as long-term depression and long-term potentiation at parallel fiber-Purkinje cell synapses, have long been seen as important to cerebellar motor learning, and yet little attention has been given to any possible significance of these processes for cerebellar dysfunction and disease. Several forms of ataxia are caused by mutations in genes encoding for ion channels located at key junctures in pathways that lead to the induction of synaptic plasticity, suggesting that there might be an association between deficits in plasticity and the ataxic phenotype. Herein we explore this possibility and examine the available evidence linking the two together, highlighting specifically the role of P/Q-type calcium channels and their downstream effector small-conductance calcium-sensitive (SK2) potassium channels in the regulation of synaptic gain and intrinsic excitability, and reviewing their connections to ataxia.
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Affiliation(s)
- L Rinaldo
- Department of Neurobiology, University of Chicago, Chicago, IL, USA
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Cong B, Han G, Huang XH, Liu SH, Liu CL, Lin XZ, He PQ, Gasaino H. Molecular cloning and tissue expression patterns of a small conductance calcium-activated potassium channel gene in turbot (Scophthalmus maximus L.). Fish Shellfish Immunol 2009; 27:221-229. [PMID: 19481607 DOI: 10.1016/j.fsi.2009.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2009] [Revised: 05/05/2009] [Accepted: 05/06/2009] [Indexed: 05/27/2023]
Abstract
Calcium-activated potassium channels on plasma membrane enable potassium influx into the cell with ensuing changes in plasma membrane potential and consequent effects on cellular metabolic functions. Recently, this potassium channel was reported to regulate the cellular responses of mammalian immune cells. We have postulated the presence of such a channel in fish immune cells and its potential role in immunoregulation in fish. Employing specific primers and RNA template, we cloned a segment of a novel gene from turbot blood sample and subsequently obtained a full cDNA sequence using RACE approaches. Bioinformatic analysis revealed structural and phylogenetic characteristics of a novel small conductance calcium-activated potassium channel gene, we called TSKCa, which exhibits homologous domains to other species particularly in the transmembrane regions. Full-length TSKCa cDNA is 1698 bp with a 1632 bp open reading frame encoding a protein of 544 amino acids. TSKCa gene is expressed in majority of the tested organs and tissues of turbot. To assess the postulated immune function of TSKCa, we infected turbot with the pathogen Vibrio anguillarum. Here, semi-quantitative RT-PCR analysis demonstrated increased mRNA expression of TSKCa in head kidney, spleen and blood, indicating an important role of TSKCa in these organ tissues that mediate the immune defense response of turbot. In contrast, there was less change in expression in the turbot intestines and liver which were less implicated in the immune response in present study.
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Affiliation(s)
- Bailin Cong
- The Key Laboratory of Marine Bioactive Substance, SOA, Qingdao 266061, PR China
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