1
|
Takla M, Edling CE, Zhang K, Saadeh K, Tse G, Salvage SC, Huang CL, Jeevaratnam K. Transcriptional profiles of genes related to electrophysiological function in Scn5a +/- murine hearts. Physiol Rep 2021; 9:e15043. [PMID: 34617689 PMCID: PMC8495800 DOI: 10.14814/phy2.15043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/13/2021] [Accepted: 08/13/2021] [Indexed: 11/24/2022] Open
Abstract
The Scn5a gene encodes the major pore-forming Nav 1.5 (α) subunit, of the voltage-gated Na+ channel in cardiomyocytes. The key role of Nav 1.5 in action potential initiation and propagation in both atria and ventricles predisposes organisms lacking Scn5a or carrying Scn5a mutations to cardiac arrhythmogenesis. Loss-of-function Nav 1.5 genetic abnormalities account for many cases of the human arrhythmic disorder Brugada syndrome (BrS) and related conduction disorders. A murine model with a heterozygous Scn5a deletion recapitulates many electrophysiological phenotypes of BrS. This study examines the relationships between its Scn5a+/- genotype, resulting transcriptional changes, and the consequent phenotypic presentations of BrS. Of 62 selected protein-coding genes related to cardiomyocyte electrophysiological or homeostatic function, concentrations of mRNA transcribed from 15 differed significantly from wild type (WT). Despite halving apparent ventricular Scn5a transcription heterozygous deletion did not significantly downregulate its atrial expression, raising possibilities of atria-specific feedback mechanisms. Most of the remaining 14 genes whose expression differed significantly between WT and Scn5a+/- animals involved Ca2+ homeostasis specifically in atrial tissue, with no overlap with any ventricular changes. All statistically significant changes in expression were upregulations in the atria and downregulations in the ventricles. This investigation demonstrates the value of future experiments exploring for and clarifying links between transcriptional control of Scn5a and of genes whose protein products coordinate Ca2+ regulation and examining their possible roles in BrS.
Collapse
Affiliation(s)
- Michael Takla
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Christ’s CollegeUniversity of CambridgeCambridgeUK
| | | | - Kevin Zhang
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- School of MedicineImperial College LondonLondonUK
| | - Khalil Saadeh
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Clinical SchoolUniversity of CambridgeCambridgeUK
| | - Gary Tse
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Second Hospital of Tianjin Medical UniversityTianjinChina
| | | | - Christopher L.‐H. Huang
- Faculty of Health and Medical ScienceUniversity of SurreyGuildfordUK
- Department of BiochemistryUniversity of CambridgeCambridgeUK
| | | |
Collapse
|
2
|
Deutsch M, Günther A, Lerchundi R, Rose CR, Balfanz S, Baumann A. AAV-Mediated CRISPRi and RNAi Based Gene Silencing in Mouse Hippocampal Neurons. Cells 2021; 10:324. [PMID: 33557342 PMCID: PMC7915209 DOI: 10.3390/cells10020324] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/27/2021] [Accepted: 01/30/2021] [Indexed: 12/12/2022] Open
Abstract
Uncovering the physiological role of individual proteins that are part of the intricate process of cellular signaling is often a complex and challenging task. A straightforward strategy of studying a protein's function is by manipulating the expression rate of its gene. In recent years, the Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9-based technology was established as a powerful gene-editing tool for generating sequence specific changes in proliferating cells. However, obtaining homogeneous populations of transgenic post-mitotic neurons by CRISPR/Cas9 turned out to be challenging. These constraints can be partially overcome by CRISPR interference (CRISPRi), which mediates the inhibition of gene expression by competing with the transcription machinery for promoter binding and, thus, transcription initiation. Notably, CRISPR/Cas is only one of several described approaches for the manipulation of gene expression. Here, we targeted neurons with recombinant Adeno-associated viruses to induce either CRISPRi or RNA interference (RNAi), a well-established method for impairing de novo protein biosynthesis by using cellular regulatory mechanisms that induce the degradation of pre-existing mRNA. We specifically targeted hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels, which are widely expressed in neuronal tissues and play essential physiological roles in maintaining biophysical characteristics in neurons. Both of the strategies reduced the expression levels of three HCN isoforms (HCN1, 2, and 4) with high specificity. Furthermore, detailed analysis revealed that the knock-down of just a single HCN isoform (HCN4) in hippocampal neurons did not affect basic electrical parameters of transduced neurons, whereas substantial changes emerged in HCN-current specific properties.
Collapse
Affiliation(s)
- Matthias Deutsch
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-1, Leo-Brandt-Straße, 52428 Jülich, Germany; (M.D.); (S.B.)
- Department of Biology, University of California, San Diego, La Jolla, CA 92083, USA
| | - Anne Günther
- Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Falkenried 94, 20251 Hamburg, Germany;
| | - Rodrigo Lerchundi
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; (R.L.); (C.R.R.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany; (R.L.); (C.R.R.)
| | - Sabine Balfanz
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-1, Leo-Brandt-Straße, 52428 Jülich, Germany; (M.D.); (S.B.)
| | - Arnd Baumann
- Forschungszentrum Jülich, Institute of Biological Information Processing, IBI-1, Leo-Brandt-Straße, 52428 Jülich, Germany; (M.D.); (S.B.)
| |
Collapse
|
3
|
Next-generation sequencing of AV nodal reentrant tachycardia patients identifies broad spectrum of variants in ion channel genes. Eur J Hum Genet 2018; 26:660-668. [PMID: 29396561 DOI: 10.1038/s41431-017-0092-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/01/2017] [Accepted: 12/05/2017] [Indexed: 12/19/2022] Open
Abstract
Atrioventricular nodal reentry tachycardia (AVNRT) is the most common form of regular paroxysmal supraventricular tachycardia. This arrhythmia affects women twice as frequently as men, and is often diagnosed in patients <40 years of age. Familial clustering, early onset of symptoms and lack of structural anomaly indicate involvement of genetic factors in AVNRT pathophysiology. We hypothesized that AVNRT patients have a high prevalence of variants in genes that are highly expressed in the atrioventricular conduction axis of the heart and potentially involved in arrhythmic diseases. Next-generation sequencing of 67 genes was applied to the DNA profile of 298 AVNRT patients and 10 AVNRT family members using HaloPlex Target Enrichment System. In total, we identified 229 variants in 60 genes; 215 missenses, four frame shifts, four codon deletions, three missense and splice sites, two stop-gain variants, and one start-lost variant. Sixty-five of these were not present in the Exome Aggregation Consortium (ExAC) database. Furthermore, we report two AVNRT families with co-segregating variants. Seventy-five of 284 AVNRT patients (26.4%) and three family members to different AVNRT probands had one or more variants in genes affecting the sodium handling. Fifty-four out of 284 AVNRT patients (19.0%) had variants in genes affecting the calcium handling of the heart. We furthermore find a large proportion of variants in the HCN1-4 genes. We did not detect a significant enrichment of rare variants in the tested genes. This could be an indication that AVNRT might be an electrical arrhythmic disease with abnormal sodium and calcium handling.
Collapse
|
4
|
Lukyanenko YO, Younes A, Lyashkov AE, Tarasov KV, Riordon DR, Lee J, Sirenko SG, Kobrinsky E, Ziman B, Tarasova YS, Juhaszova M, Sollott SJ, Graham DR, Lakatta EG. Ca(2+)/calmodulin-activated phosphodiesterase 1A is highly expressed in rabbit cardiac sinoatrial nodal cells and regulates pacemaker function. J Mol Cell Cardiol 2016; 98:73-82. [PMID: 27363295 DOI: 10.1016/j.yjmcc.2016.06.064] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 05/23/2016] [Accepted: 06/23/2016] [Indexed: 11/29/2022]
Abstract
Constitutive Ca(2+)/calmodulin (CaM)-activation of adenylyl cyclases (ACs) types 1 and 8 in sinoatrial nodal cells (SANC) generates cAMP within lipid-raft-rich microdomains to initiate cAMP-protein kinase A (PKA) signaling, that regulates basal state rhythmic action potential firing of these cells. Mounting evidence in other cell types points to a balance between Ca(2+)-activated counteracting enzymes, ACs and phosphodiesterases (PDEs) within these cells. We hypothesized that the expression and activity of Ca(2+)/CaM-activated PDE Type 1A is higher in SANC than in other cardiac cell types. We found that PDE1A protein expression was 5-fold higher in sinoatrial nodal tissue than in left ventricle, and its mRNA expression was 12-fold greater in the corresponding isolated cells. PDE1 activity (nimodipine-sensitive) accounted for 39% of the total PDE activity in SANC lysates, compared to only 4% in left ventricular cardiomyocytes (LVC). Additionally, total PDE activity in SANC lysates was lowest (10%) in lipid-raft-rich and highest (76%) in lipid-raft-poor fractions (equilibrium sedimentation on a sucrose density gradient). In intact cells PDE1A immunolabeling was not localized to the cell surface membrane (structured illumination microscopy imaging), but located approximately within about 150nm inside of immunolabeling of hyperpolarization-activated cyclic nucleotide-gated potassium channels (HCN4), which reside within lipid-raft-rich microenvironments. In permeabilized SANC, in which surface membrane ion channels are not functional, nimodipine increased spontaneous SR Ca(2+) cycling. PDE1A mRNA silencing in HL-1 cells increased the spontaneous beating rate, reduced the cAMP, and increased cGMP levels in response to IBMX, a broad spectrum PDE inhibitor (detected via fluorescence resonance energy transfer microscopy). We conclude that signaling via cAMP generated by Ca(2+)/CaM-activated AC in SANC lipid raft domains is limited by cAMP degradation by Ca(2+)/CaM-activated PDE1A in non-lipid raft domains. This suggests that local gradients of [Ca(2+)]-CaM or different AC and PDE1A affinity regulate both cAMP production and its degradation, and this balance determines the intensity of Ca(2+)-AC-cAMP-PKA signaling that drives SANC pacemaker function.
Collapse
Affiliation(s)
- Yevgeniya O Lukyanenko
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Antoine Younes
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Alexey E Lyashkov
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA; Department of Molecular and Comparative Pathobiology, Johns Hopkins School of Medicine, 733 N. Broadway, MRB 835, Baltimore, MD 21205, USA.
| | - Kirill V Tarasov
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Daniel R Riordon
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Joonho Lee
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Syevda G Sirenko
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Evgeny Kobrinsky
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Bruce Ziman
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Yelena S Tarasova
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Magdalena Juhaszova
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| | - David R Graham
- Department of Molecular and Comparative Pathobiology, Johns Hopkins School of Medicine, 733 N. Broadway, MRB 835, Baltimore, MD 21205, USA.
| | - Edward G Lakatta
- Laboratory of Cardiovascular Science, National Institute on Aging, 251 Bayview Blvd., Baltimore, MD 21224, USA.
| |
Collapse
|