1
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Chaudhari S, Acharya LP, Jasti DB, Ware AP, Gorthi SP, Satyamoorthy K. Discovery of a Novel Shared Variant Among RTEL1 Gene and RTEL1-TNFRSF6B lncRNA at Chromosome 20q13.33 in Familial Progressive Myoclonus Epilepsy. Int J Genomics 2024; 2024:7518528. [PMID: 39156922 PMCID: PMC11330336 DOI: 10.1155/2024/7518528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 04/17/2024] [Accepted: 07/20/2024] [Indexed: 08/20/2024] Open
Abstract
Background: Progressive myoclonus epilepsy (PME) is a neurodegenerative disorder marked by recurrent seizures and progressive myoclonus. To date, based on the phenotypes and causal genes, more than 40 subtypes of PMEs have been identified, and more remain to be characterized. Our study is aimed at identifying the aberrant gene(s) possibly associated with PMEs in two siblings born to asymptomatic parents, in the absence of known genetic mutations. Methods: Clinical assessments and molecular analyses, such as the repeat expansion test for CSTB; SCA1, 2, 3, 6, and 7; whole exome sequencing (WES); and mitochondrial genome sequencing coupled with computational analysis, were performed. Results: A family-based segregation analysis of WES data was performed to identify novel genes associated with PMEs. The potassium channel, KCNH8 [c.298T>C; (p.Tyr100His)], a DNA repair gene, regulator of telomere elongation helicase 1 (RTEL1) [c.691G>T; (p.Asp231Tyr)] and long noncoding RNA, RTEL1-TNFRSF6B [chr20:62298898_G>T; NR_037882.1, hg19] were among the candidate genes that were found to be associated with PMEs. These homozygous variations in siblings belong to genes with a loss-of-function intolerant (pLI) score of ≤ 0.86, expected to be detrimental by multiple computational analyses, and were heterozygous in parents. Additionally, computational analysis and the expression of RTEL1 and RTEL1-TNFRSF6B revealed that RTEL1-TNFRSF6B may modulate RTEL1 via hsa-miR-3529-3p. In the patient with the severe phenotype, a further deleterious mutation in SLC22A17 was identified. No de novo variants specific to these probands were identified in the mitochondrial genome. Conclusions: Our study is the first to report variants in KCNH8, RTEL1, and RTEL1-TNFRSF6B among PME cases. These genes when characterized fully may shed light on pathogenicity and have the potential to be used in the diagnosis of PME.
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Affiliation(s)
- Sima Chaudhari
- Department of Cell and Molecular BiologyManipal School of Life SciencesManipal Academy of Higher Education 576104, Manipal, Karnataka, India
| | - Lavanya Prakash Acharya
- Department of Cell and Molecular BiologyManipal School of Life SciencesManipal Academy of Higher Education 576104, Manipal, Karnataka, India
| | - Dushyanth Babu Jasti
- Department of NeurologyKasturba Medical College 576104, Manipal, Karnataka, India
| | - Akshay Pramod Ware
- Department of BioinformaticsManipal School of Life SciencesManipal Academy of Higher Education 576104, Manipal, Karnataka, India
| | - Sankar Prasad Gorthi
- Department of NeurologyKasturba Medical College 576104, Manipal, Karnataka, India
- Department of NeurologyBharati Hospital and Research CenterBharati Vidyapeeth (Deemed to Be University) Medical College and Hospital, Dhankawadi 411043, Pune, Maharashtra, India
| | - Kapaettu Satyamoorthy
- Department of Cell and Molecular BiologyManipal School of Life SciencesManipal Academy of Higher Education 576104, Manipal, Karnataka, India
- SDM College of Medical Sciences and HospitalShri Dharmasthala Manjunatheshwara (SDM) University, Manjushree Nagar, Sattur 580009, Dharwad, Karnataka, India
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2
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Singh V, Auerbach DS. Neurocardiac pathologies associated with potassium channelopathies. Epilepsia 2024. [PMID: 39087855 DOI: 10.1111/epi.18066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 07/10/2024] [Accepted: 07/10/2024] [Indexed: 08/02/2024]
Abstract
Voltage-gated potassium channels are expressed throughout the human body and are essential for physiological functions. These include delayed rectifiers, A-type channels, outward rectifiers, and inward rectifiers. They impact electrical function in the heart (repolarization) and brain (repolarization and stabilization of the resting membrane potential). KCNQx and KCNHx encode Kv7.x and Kv11.x proteins, which form delayed rectifier potassium channels. KCNQx and KCNHx channelopathies are associated with both cardiac and neuronal pathologies. These include electrocardiographic abnormalities, cardiac arrhythmias, sudden cardiac death (SCD), epileptiform discharges, seizures, bipolar disorder, and sudden unexpected death in epilepsy (SUDEP). Due to the ubiquitous expression of KCNQx and KCNHx channels, abnormalities in their function can be particularly harmful, increasing the risk of sudden death. For example, KCNH2 variants have a dual role in both cardiac and neuronal pathologies, whereas KCNQ2 and KCNQ3 variants are associated with severe and refractory epilepsy. Recurrent and uncontrolled seizures lead to secondary abnormalities, which include autonomics, cardiac electrical function, respiratory drive, and neuronal electrical activity. Even with a wide array of anti-seizure therapies available on the market, one-third of the more than 70 million people worldwide with epilepsy have uncontrolled seizures (i.e., intractable/drug-resistant epilepsy), which negatively impact neurodevelopment and quality of life. To capture the current state of the field, this review examines KCNQx and KCNHx expression patterns and electrical function in the brain and heart. In addition, it discusses several KCNQx and KCNHx variants that have been clinically and electrophysiologically characterized. Because these channel variants are associated with multi-system pathologies, such as epileptogenesis, Kv7 channel modulators provide a potential anti-seizure therapy, particularly for people with intractable epilepsy. Ultimately an increased understanding of the role of Kv channels throughout the body will fuel the development of innovative, safe, and effective therapies for people at a high risk of sudden death (SCD and SUDEP).
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Affiliation(s)
- Veronica Singh
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York, USA
| | - David S Auerbach
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York, USA
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3
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Hermanstyne TO, Yang ND, Granados-Fuentes D, Li X, Mellor RL, Jegla T, Herzog ED, Nerbonne JM. Kv12-encoded K+ channels drive the day-night switch in the repetitive firing rates of SCN neurons. J Gen Physiol 2023; 155:e202213310. [PMID: 37516908 PMCID: PMC10373311 DOI: 10.1085/jgp.202213310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 05/11/2023] [Accepted: 07/06/2023] [Indexed: 07/31/2023] Open
Abstract
Considerable evidence suggests that day-night rhythms in the functional expression of subthreshold potassium (K+) channels regulate daily oscillations in the spontaneous firing rates of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals. The K+ conductance(s) driving these daily rhythms in the repetitive firing rates of SCN neurons, however, have not been identified. To test the hypothesis that subthreshold Kv12.1/Kv12.2-encoded K+ channels play a role, we obtained current-clamp recordings from SCN neurons in slices prepared from adult mice harboring targeted disruptions in the Kcnh8 (Kv12.1-/-) or Kcnh3 (Kv12.2-/-) locus. We found that mean nighttime repetitive firing rates were higher in Kv12.1-/- and Kv12.2-/- than in wild type (WT), SCN neurons. In marked contrast, mean daytime repetitive firing rates were similar in Kv12.1-/-, Kv12.2-/-, and WT SCN neurons, and the day-night difference in mean repetitive firing rates, a hallmark feature of WT SCN neurons, was eliminated in Kv12.1-/- and Kv12.2-/- SCN neurons. Similar results were obtained with in vivo shRNA-mediated acute knockdown of Kv12.1 or Kv12.2 in adult SCN neurons. Voltage-clamp experiments revealed that Kv12-encoded current densities in WT SCN neurons are higher at night than during the day. In addition, the pharmacological block of Kv12-encoded currents increased the mean repetitive firing rate of nighttime, but not daytime, in WT SCN neurons. Dynamic clamp-mediated subtraction of modeled Kv12-encoded currents also selectively increased the mean repetitive firing rates of nighttime WT SCN neurons. Despite the elimination of the nighttime decrease in the mean repetitive firing rates of SCN neurons, however, locomotor (wheel-running) activity remained rhythmic in Kv12.1-/-, Kv12.2-/-, and Kv12.1-targeted shRNA-expressing, and Kv12.2-targeted shRNA-expressing animals.
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Affiliation(s)
- Tracey O. Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nien-Du Yang
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | | | - Xiaofan Li
- Department of Biology, The Pennsylvania State University, University Park, State College, PA, USA
| | - Rebecca L. Mellor
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Timothy Jegla
- Department of Biology, The Pennsylvania State University, University Park, State College, PA, USA
| | - Erik D. Herzog
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Jeanne M. Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
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4
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Xing J, Gumerov VM, Zhulin IB. Origin and functional diversification of PAS domain, a ubiquitous intracellular sensor. SCIENCE ADVANCES 2023; 9:eadi4517. [PMID: 37647406 PMCID: PMC10468136 DOI: 10.1126/sciadv.adi4517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 07/28/2023] [Indexed: 09/01/2023]
Abstract
Signal perception is a key function in regulating biological activities and adapting to changing environments. Per-Arnt-Sim (PAS) domains are ubiquitous sensors found in diverse receptors in bacteria, archaea, and eukaryotes, but their origins, distribution across the tree of life, and extent of their functional diversity are not fully characterized. Here, we show that using sequence conservation and structural information, it is possible to propose specific and potential functions for a large portion of nearly 3 million PAS domains. Our analysis suggests that PAS domains originated in bacteria and were horizontally transferred to archaea and eukaryotes. We reveal that gas sensing via a heme cofactor evolved independently in several lineages, whereas redox and light sensing via flavin adenine dinucleotide and flavin mononucleotide cofactors have the same origin. The close relatedness of human PAS domains to those in bacteria provides an opportunity for drug design by exploring potential natural ligands and cofactors for bacterial homologs.
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Affiliation(s)
- Jiawei Xing
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, OH USA
| | - Vadim M. Gumerov
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, OH USA
| | - Igor B. Zhulin
- Department of Microbiology, The Ohio State University, Columbus, OH, USA
- Translational Data Analytics Institute, The Ohio State University, Columbus, OH USA
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5
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Hermanstyne TO, Yang ND, Granados-Fuentes D, Li X, Mellor RL, Jegla T, Herzog ED, Nerbonne JM. Kv12-Encoded K + Channels Drive the Day-Night Switch in the Repetitive Firing Rates of SCN Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526323. [PMID: 36778242 PMCID: PMC9915524 DOI: 10.1101/2023.01.30.526323] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Considerable evidence suggests that day-night rhythms in the functional expression of subthreshold potassium (K + ) channels regulate daily oscillations in the rates of spontaneous action potential firing of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals. The K + conductance(s) driving these daily rhythms in repetitive firing rates, however, have not been identified. To test the hypothesis that subthreshold Kv12.1/Kv12.2-encoded K + channels play a role, we obtained current-clamp recordings from SCN neurons in slices prepared from adult mice harboring targeted disruptions in the Kcnh8 (Kv12.1 -/- ) or Kcnh3 (Kv12.2 -/- ) locus. We found that mean nighttime repetitive firing rates were higher in Kv12.1 -/- and Kv12.2 -/- , than in wild type (WT), SCN neurons. In marked contrast, mean daytime repetitive firing rates were similar in Kv12.1 -/- , Kv12.2 -/- and WT SCN neurons, and the day-night difference in mean repetitive firing rates, a hallmark feature of WT SCN neurons, was eliminated in Kv12.1 -/- and Kv12.2 -/- SCN neurons. Similar results were obtained with in vivo shRNA-mediated acute knockdown of Kv12.1 or Kv12.2 in adult SCN neurons. Voltage-clamp experiments revealed that Kv12-encoded current densities in WT SCN neurons are higher at night than during the day. In addition, pharmacological block of Kv12-encoded currents increased the mean repetitive firing rate of nighttime, but not daytime, in WT SCN neurons. Dynamic clamp-mediated subtraction of modeled Kv12-encoded currents also selectively increased the mean repetitive firing rates of nighttime WT SCN neurons. Despite the elimination of nighttime decrease in the mean repetitive firing rates of SCN neurons, however, locomotor (wheel-running) activity remained rhythmic in Kv12.1 -/- , Kv12.2 -/- , Kv12.1-targeted shRNA-expressing, and Kv12.2-targeted shRNA-expressing animals.
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Affiliation(s)
- Tracey O. Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Nien-Du Yang
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO
| | | | - Xiaofan Li
- Department of Biology, The Pennsylvania State University, University Park, PA
| | - Rebecca L. Mellor
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
| | - Timothy Jegla
- Department of Biology, The Pennsylvania State University, University Park, PA
| | - Erik D. Herzog
- Department of Biology, Washington University, St. Louis, MO
| | - Jeanne M. Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO
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6
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Increased Expression of the RBPMS Splice Variants Inhibits Cell Proliferation in Ovarian Cancer Cells. Int J Mol Sci 2022; 23:ijms232314742. [PMID: 36499073 PMCID: PMC9738375 DOI: 10.3390/ijms232314742] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Revised: 11/22/2022] [Accepted: 11/23/2022] [Indexed: 11/29/2022] Open
Abstract
RNA-Binding Protein with Multiple Splicing (RBPMS) is a member of family proteins that bind to nascent RNA transcripts and regulate their splicing, localization, and stability. Evidence indicates that RBPMS controls the activity of transcription factors associated with cell growth and proliferation, including AP-1 and Smads. Three major RBPMS protein splice variants (RBPMSA, RBPMSB, and RBPMSC) have been described in the literature. We previously reported that reduced RBPMS levels decreased the sensitivity of ovarian cancer cells to cisplatin treatment. However, little is known about the biological role of the RBPMS splice variants in ovarian cancer cells. We performed RT-PCR and Western blots and observed that both RBPMSA and RBPMSC are reduced at the mRNA and protein levels in cisplatin resistant as compared with cisplatin sensitive ovarian cancer cells. The mRNA and protein levels of RBPMSB were not detectable in any of the ovarian cancer cells tested. To better understand the biological role of each RBPMSA and RBPMSC, we transfected these two splice variants in the A2780CP20 and OVCAR3CIS cisplatin resistant ovarian cancer cells and performed cell proliferation, cell migration, and invasion assays. Compared with control clones, a significant reduction in the number of colonies, colony size, cell migration, and invasion was observed with RBPMSA and RBPMSC overexpressed cells. Moreover, A2780CP20-RBPMSA and A2780CP20-RBPMSC clones showed reduced senescence-associated β-galactosidase (β-Gal)-levels when compared with control clones. A2780CP20-RBPMSA clones were more sensitive to cisplatin treatment as compared with A2780CP20-RBPMSC clones. The A2780CP20-RBPMSA and A2780CP20-RBPMSC clones subcutaneously injected into athymic nude mice formed smaller tumors as compared with A2780CP20-EV control group. Additionally, immunohistochemical analysis showed lower proliferation (Ki67) and angiogenesis (CD31) staining in tissue sections of A2780CP20-RBPMSA and A2780CP20-RBPMSC tumors compared with controls. RNAseq studies revealed many common RNA transcripts altered in A2780CP20-RBPMSA and A2780CP20-RBPMSC clones. Unique RNA transcripts deregulated by each RBPMS variant were also observed. Kaplan-Meier (KM) plotter database information identified clinically relevant RBPMSA and RBPMSC downstream effectors. These studies suggest that increased levels of RBPMSA and RBPMSC reduce cell proliferation in ovarian cancer cells. However, only RBPMSA expression levels were associated with the sensitivity of ovarian cancer cells to cisplatin treatment.
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7
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Xie S, Yang J, Huang S, Fan Y, Xu T, He J, Guo J, Ji X, Wang Z, Li P, Chen J, Zhang Y. Disrupted myelination network in the cingulate cortex of Parkinson's disease. IET Syst Biol 2022; 16:98-119. [PMID: 35394697 PMCID: PMC9290774 DOI: 10.1049/syb2.12043] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/31/2022] [Accepted: 03/21/2022] [Indexed: 12/13/2022] Open
Abstract
The cingulate cortex is part of the conserved limbic system, which is considered as a hub of emotional and cognitive control. Accumulating evidence suggested that involvement of the cingulate cortex is significant for cognitive impairment of Parkinson's disease (PD). However, mechanistic studies of the cingulate cortex in PD pathogenesis are limited. Here, transcriptomic and regulatory network analyses were conducted for the cingulate cortex in PD. Enrichment and clustering analyses showed that genes involved in regulation of membrane potential and glutamate receptor signalling pathway were upregulated. Importantly, myelin genes and the oligodendrocyte development pathways were markedly downregulated, indicating disrupted myelination in PD cingulate cortex. Cell‐type‐specific signatures revealed that myelinating oligodendrocytes were the major cell type damaged in the PD cingulate cortex. Furthermore, downregulation of myelination pathways in the cingulate cortex were shared and validated in another independent RNAseq cohort of dementia with Lewy bodies (DLB). In combination with ATACseq data, gene regulatory networks (GRNs) were further constructed for 32 transcription factors (TFs) and 466 target genes among differentially expressed genes (DEGs) using a tree‐based machine learning algorithm. Several transcription factors, including Olig2, Sox8, Sox10, E2F1, and NKX6‐2, were highlighted as key nodes in a sub‐network, which control many overlapping downstream targets associated with myelin formation and gliogenesis. In addition, the authors have validated a subset of DEGs by qPCRs in two PD mouse models. Notably, seven of these genes,TOX3, NECAB2 NOS1, CAPN3, NR4A2, E2F1 and FOXP2, have been implicated previously in PD or neurodegeneration and are worthy of further studies as novel candidate genes. Together, our findings provide new insights into the role of remyelination as a promising new approach to treat PD after demyelination.
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Affiliation(s)
- Song Xie
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jiajun Yang
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Shenghui Huang
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yuanlan Fan
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Tao Xu
- Molecular Neuropharmacology Lab, School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,The Eye-Brain Research Center, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou, Zhejiang Province, China
| | - Jiangshuang He
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jiahao Guo
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Xiang Ji
- Department of Mathematics, School of Science & Engineering, Tulane University, New Orleans, Louisiana, USA
| | - Zhibo Wang
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Peijun Li
- The Second Affiliated Hospital and Yuying Children's Hospital, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jiangfan Chen
- Molecular Neuropharmacology Lab, School of Optometry and Ophthalmology, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,The Eye-Brain Research Center, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou, Zhejiang Province, China
| | - Yi Zhang
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou, Zhejiang Province, China.,The Eye-Brain Research Center, State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou, Zhejiang Province, China.,Key Laboratory of Alzheimer's Disease of Zhejiang Province, Institute of Aging, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
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8
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Ma Z, Hu X, Ding HF, Zhang M, Huo Y, Dong Z. Single-Nucleus Transcriptional Profiling of Chronic Kidney Disease after Cisplatin Nephrotoxicity. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:613-628. [PMID: 35092726 PMCID: PMC8978211 DOI: 10.1016/j.ajpath.2021.12.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/12/2021] [Accepted: 12/16/2021] [Indexed: 01/09/2023]
Abstract
Cisplatin induces both acute and chronic nephrotoxicity during chemotherapy in patients with cancer. Presented here is the first study of single-nucleus RNA sequencing (snRNA-seq) of cisplatin-induced nephrotoxicity. Repeated low-dose cisplatin treatment (RLDC) led to decreases in renal function and kidney weight in mice at 9 weeks. The kidneys of these mice showed tubular degeneration and dilation. snRNA-seq identified 16 cell types and 17 cell clusters in these kidneys. Cluster-by-cluster comparison demonstrated cell type-specific changes in gene expression and identified a unique proximal tubule (PT) injury/repair cluster that co-expressed the injury marker kidney injury molecule-1 (Kim1) and the proliferation marker Ki-67. Compared with control, post-RLDC kidneys had 424 differentially expressed genes in PT cells, including tubular transporters and cytochrome P450 enzymes involved in lipid metabolism. snRNA-seq also revealed transcriptional changes in potential PT injury markers (Krt222, Eda2r, Ltbp2, and Masp1) and repair marker (Bex4). RLDC induced inflammation and proinflammatory cytokines (RelB, TNF-α, Il7, Ccl2, and Cxcl2) and the expression of fibrosis markers (fibronectin, collagen I, connective tissue growth factor, vimentin, and α-smooth muscle actin). Together, these results provide new insights into RLDC-induced transcriptional changes at the single-cell level that may contribute to the development of chronic kidney problems in patients with cancer after cisplatin chemotherapy.
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Affiliation(s)
- Zhengwei Ma
- Department of Cellular Biology and Anatomy, Vascular Biology Center, Augusta, Georgia.
| | - Xiaoru Hu
- Department of Cellular Biology and Anatomy, Vascular Biology Center, Augusta, Georgia; Department of Nephrology, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Han-Fei Ding
- Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Ming Zhang
- Department of Cellular Biology and Anatomy, Vascular Biology Center, Augusta, Georgia
| | - Yuqing Huo
- Department of Cellular Biology and Anatomy, Vascular Biology Center, Augusta, Georgia; Medical College of Georgia at Augusta University, Augusta, Georgia
| | - Zheng Dong
- Department of Cellular Biology and Anatomy, Vascular Biology Center, Augusta, Georgia; Charlie Norwood VA Medical Center, Augusta, Georgia.
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Codding SJ, Johnson AA, Trudeau MC. Gating and regulation of KCNH (ERG, EAG, and ELK) channels by intracellular domains. Channels (Austin) 2021; 14:294-309. [PMID: 32924766 PMCID: PMC7515569 DOI: 10.1080/19336950.2020.1816107] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The KCNH family comprises the ERG, EAG, and ELK voltage-activated, potassium-selective channels. Distinct from other K channels, KCNH channels contain unique structural domains, including a PAS (Per-Arnt-Sim) domain in the N-terminal region and a CNBHD (cyclic nucleotide-binding homology domain) in the C-terminal region. The intracellular PAS domains and CNBHDs interact directly and regulate some of the characteristic gating properties of each type of KCNH channel. The PAS-CNBHD interaction regulates slow closing (deactivation) of hERG channels, the kinetics of activation and pre-pulse dependent population of closed states (the Cole-Moore shift) in EAG channels and voltage-dependent potentiation in ELK channels. KCNH channels are all regulated by an intrinsic ligand motif in the C-terminal region which binds to the CNBHD. Here, we focus on some recent advances regarding the PAS-CNBHD interaction and the intrinsic ligand.
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Affiliation(s)
- Sara J Codding
- Department of Physiology, University of Maryland School of Medicine , Baltimore, MD, USA
| | - Ashley A Johnson
- Department of Physiology, University of Maryland School of Medicine , Baltimore, MD, USA
| | - Matthew C Trudeau
- Department of Physiology, University of Maryland School of Medicine , Baltimore, MD, USA
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10
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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11
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Genetic Polymorphisms Related to VO2max Adaptation Are Associated With Elite Rugby Union Status and Competitive Marathon Performance. Int J Sports Physiol Perform 2021; 16:1858-1864. [PMID: 34088882 DOI: 10.1123/ijspp.2020-0856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 02/19/2021] [Accepted: 03/23/2021] [Indexed: 11/18/2022]
Abstract
PURPOSE Genetic polymorphisms have been associated with the adaptation to training in maximal oxygen uptake (V˙O2max). However, the genotype distribution of selected polymorphisms in athletic cohorts is unknown, with their influence on performance characteristics also undetermined. This study investigated whether the genotype distributions of 3 polymorphisms previously associated with V˙O2max training adaptation are associated with elite athlete status and performance characteristics in runners and rugby athletes, competitors for whom aerobic metabolism is important. METHODS Genomic DNA was collected from 732 men including 165 long-distance runners, 212 elite rugby union athletes, and 355 nonathletes. Genotype and allele frequencies of PRDM1 rs10499043 C/T, GRIN3A rs1535628 G/A, and KCNH8 rs4973706 T/C were compared between athletes and nonathletes. Personal-best marathon times in runners, as well as in-game performance variables and playing position, of rugby athletes were analyzed according to genotype. RESULTS Runners with PRDM1 T alleles recorded marathon times ∼3 minutes faster than CC homozygotes (02:27:55 [00:07:32] h vs 02:31:03 [00:08:24] h, P = .023). Rugby athletes had 1.57 times greater odds of possessing the KCNH8 TT genotype than nonathletes (65.5% vs 54.7%, χ2 = 6.494, P = .013). No other associations were identified. CONCLUSIONS This study is the first to demonstrate that polymorphisms previously associated with V˙O2max training adaptations in nonathletes are also associated with marathon performance (PRDM1) and elite rugby union status (KCNH8). The genotypes and alleles previously associated with superior endurance-training adaptation appear to be advantageous in long-distance running and achieving elite status in rugby union.
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12
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Schartl M, Kneitz S, Ormanns J, Schmidt C, Anderson JL, Amores A, Catchen J, Wilson C, Geiger D, Du K, Garcia-Olazábal M, Sudaram S, Winkler C, Hedrich R, Warren WC, Walter R, Meyer A, Postlethwait JH. The Developmental and Genetic Architecture of the Sexually Selected Male Ornament of Swordtails. Curr Biol 2021; 31:911-922.e4. [PMID: 33275891 PMCID: PMC8580132 DOI: 10.1016/j.cub.2020.11.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 10/12/2020] [Accepted: 11/11/2020] [Indexed: 12/21/2022]
Abstract
Sexual selection results in sex-specific characters like the conspicuously pigmented extension of the ventral tip of the caudal fin-the "sword"-in males of several species of Xiphophorus fishes. To uncover the genetic architecture underlying sword formation and to identify genes that are associated with its development, we characterized the sword transcriptional profile and combined it with genetic mapping approaches. Results showed that the male ornament of swordtails develops from a sexually non-dimorphic prepattern of transcription factors in the caudal fin. Among genes that constitute the exclusive sword transcriptome and are located in the genomic region associated with this trait we identify the potassium channel, Kcnh8, as a sword development gene. In addition to its neural function kcnh8 performs a known role in fin growth. These findings indicate that during evolution of swordtails a brain gene has been co-opted for an additional novel function in establishing a male ornament.
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Affiliation(s)
- Manfred Schartl
- Developmental Biochemistry, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany; The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA.
| | - Susanne Kneitz
- Biochemistry and Cell Biology, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Jenny Ormanns
- Biochemistry and Cell Biology, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Cornelia Schmidt
- Biochemistry and Cell Biology, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany
| | - Jennifer L Anderson
- Systematic Biology, Department of Organismal Biology, Uppsala University, Norbyvägen 18D, 752 36 Uppsala, Sweden
| | - Angel Amores
- Institute of Neuroscience, University of Oregon, Eugene, OR 97401, USA
| | - Julian Catchen
- Department of Animal Biology, University of Illinois, Urbana, IL 6812, USA
| | - Catherine Wilson
- Institute of Neuroscience, University of Oregon, Eugene, OR 97401, USA
| | - Dietmar Geiger
- Julius-von-Sachs-Institute for Biosciences, Molecular Plant Physiology and Biophysics, Biocenter, University Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Kang Du
- Developmental Biochemistry, Biocenter, University of Wuerzburg, Am Hubland, 97074 Wuerzburg, Germany; The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | | | - Sudha Sudaram
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Christoph Winkler
- Department of Biological Sciences and Centre for Bioimaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Rainer Hedrich
- Julius-von-Sachs-Institute for Biosciences, Molecular Plant Physiology and Biophysics, Biocenter, University Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Wesley C Warren
- 440G Bond Life Sciences Center, 1201 Rollins Street, University of Missouri, Columbia, MO 65211, USA
| | - Ronald Walter
- The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, TX 78666, USA
| | - Axel Meyer
- Lehrstuhl für Zoologie und Evolutionsbiologie, Department of Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
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13
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Zhang S, Zhang X, Purmann C, Ma S, Shrestha A, Davis KN, Ho M, Huang Y, Pattni R, Hung Wong W, Bernstein JA, Hallmayer J, Urban AE. Network Effects of the 15q13.3 Microdeletion on the Transcriptome and Epigenome in Human-Induced Neurons. Biol Psychiatry 2021; 89:497-509. [PMID: 32919612 PMCID: PMC9359316 DOI: 10.1016/j.biopsych.2020.06.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND The 15q13.3 microdeletion is associated with several neuropsychiatric disorders, including autism and schizophrenia. Previous association and functional studies have investigated the potential role of several genes within the deletion in neuronal dysfunction, but the molecular effects of the deletion as a whole remain largely unknown. METHODS Induced pluripotent stem cells, from 3 patients with the 15q13.3 microdeletion and 3 control subjects, were generated and converted into induced neurons. We analyzed the effects of the 15q13.3 microdeletion on genome-wide gene expression, DNA methylation, chromatin accessibility, and sensitivity to cisplatin-induced DNA damage. Furthermore, we measured gene expression changes in induced neurons with CRISPR (clustered regularly interspaced short palindromic repeats) knockouts of individual 15q13.3 microdeletion genes. RESULTS In both induced pluripotent stem cells and induced neurons, gene copy number change within the 15q13.3 microdeletion was accompanied by significantly decreased gene expression and no compensatory changes in DNA methylation or chromatin accessibility, supporting the model that haploinsufficiency of genes within the deleted region drives the disorder. Furthermore, we observed global effects of the microdeletion on the transcriptome and epigenome, with disruptions in several neuropsychiatric disorder-associated pathways and gene families, including Wnt signaling, ribosome function, DNA binding, and clustered protocadherins. Individual gene knockouts mirrored many of the observed changes in an overlapping fashion between knockouts. CONCLUSIONS Our multiomics analysis of the 15q13.3 microdeletion revealed downstream effects in pathways previously associated with neuropsychiatric disorders and indications of interactions between genes within the deletion. This molecular systems analysis can be applied to other chromosomal aberrations to further our etiological understanding of neuropsychiatric disorders.
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Affiliation(s)
- Siming Zhang
- Department of Genetics, School of Humanities and Science, Stanford University, Stanford, California
| | - Xianglong Zhang
- Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California
| | - Carolin Purmann
- Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California
| | - Shining Ma
- Department of Pediatrics, School of Humanities and Sciences, Stanford University, Stanford, California
| | - Anima Shrestha
- School of Medicine, Stanford University, and Department of Statistics, School of Humanities and Sciences, Stanford University, Stanford, California
| | - Kasey N Davis
- Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California
| | - Marcus Ho
- Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California
| | - Yiling Huang
- Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California
| | - Reenal Pattni
- Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California
| | - Wing Hung Wong
- Department of Pediatrics, School of Humanities and Sciences, Stanford University, Stanford, California
| | - Jonathan A Bernstein
- Department of Human Biology, School of Humanities and Science, Stanford University, Stanford, California
| | - Joachim Hallmayer
- Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California
| | - Alexander E Urban
- Department of Genetics, School of Humanities and Science, Stanford University, Stanford, California; Department of Psychiatry and Behavioral Sciences, School of Humanities and Science, Stanford University, Stanford, California.
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14
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Demontis GC, Pezzini F, Margari E, Bianchi M, Longoni B, Doccini S, Lalowski MM, Santorelli FM, Simonati A. Electrophysiological Profile Remodeling via Selective Suppression of Voltage-Gated Currents by CLN1/PPT1 Overexpression in Human Neuronal-Like Cells. Front Cell Neurosci 2020; 14:569598. [PMID: 33390903 PMCID: PMC7772423 DOI: 10.3389/fncel.2020.569598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 11/18/2020] [Indexed: 12/21/2022] Open
Abstract
CLN1 disease (OMIM #256730) is an inherited neurological disorder of early childhood with epileptic seizures and premature death. It is associated with mutations in CLN1 coding for Palmitoyl-Protein Thioesterase 1 (PPT1), a lysosomal enzyme which affects the recycling and degradation of lipid-modified (S-acylated) proteins by removing palmitate residues. Transcriptomic evidence from a neuronal-like cellular model derived from differentiated SH-SY5Y cells disclosed the potential negative roles of CLN1 overexpression, affecting the elongation of neuronal processes and the expression of selected proteins of the synaptic region. Bioinformatic inquiries of transcriptomic data pinpointed a dysregulated expression of several genes coding for proteins related to voltage-gated ion channels, including subunits of calcium and potassium channels (VGCC and VGKC). In SH-SY5Y cells overexpressing CLN1 (SH-CLN1 cells), the resting potential and the membrane conductance in the range of voltages close to the resting potential were not affected. However, patch-clamp recordings indicated a reduction of Ba2+ currents through VGCC of SH-CLN1 cells; Ca2+ imaging revealed reduced Ca2+ influx in the same cellular setting. The results of the biochemical and morphological investigations of CACNA2D2/α2δ-2, an accessory subunit of VGCC, were in accordance with the downregulation of the corresponding gene and consistent with the hypothesis that a lower number of functional channels may reach the plasma membrane. The combined use of 4-AP and NS-1643, two drugs with opposing effects on Kv11 and Kv12 subfamilies of VGKC coded by the KCNH gene family, provides evidence for reduced functional Kv12 channels in SH-CLN1 cells, consistent with transcriptomic data indicating the downregulation of KCNH4. The lack of compelling evidence supporting the palmitoylation of many ion channels subunits investigated in this study stimulates inquiries about the role of PPT1 in the trafficking of channels to the plasma membrane. Altogether, these results indicate a reduction of functional voltage-gated ion channels in response to CLN1/PPT1 overexpression in differentiated SH-SY5Y cells and provide new insights into the altered neuronal excitability which may underlie the severe epileptic phenotype of CLN1 disease. It remains to be shown if remodeling of such functional channels on plasma membrane can occur as a downstream effect of CLN1 disease.
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Affiliation(s)
| | - Francesco Pezzini
- Neurology (Child Neurology and Neuropathology), Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy
| | - Elisa Margari
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Marzia Bianchi
- Research Unit for Multi-factorial Diseases, Obesity and Diabetes, Bambino Gesù Children's Hospital Istituto di Ricerca e Cura a Carattere Scientifico, Rome, Italy
| | - Biancamaria Longoni
- Department of Translational Research and New Technology in Medicine, University of Pisa, Pisa, Italy
| | - Stefano Doccini
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, Istituto di Ricerca e Cura a Carattere Scientifico Stella Maris Foundation, Pisa, Italy
| | - Maciej Maurycy Lalowski
- Medicum, Biochemistry/Developmental Biology and HiLIFE-Helsinki Institute of Life Science, Meilahti Clinical Proteomics Core Facility, University of Helsinki, Helsinki, Finland
| | - Filippo Maria Santorelli
- Molecular Medicine for Neurodegenerative and Neuromuscular Diseases Unit, Istituto di Ricerca e Cura a Carattere Scientifico Stella Maris Foundation, Pisa, Italy
| | - Alessandro Simonati
- Neurology (Child Neurology and Neuropathology), Department of Neuroscience, Biomedicine and Movement, University of Verona, Verona, Italy
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15
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Manzi C, Vergara-Amado J, Franco LM, Silva AX. The effect of temperature on candidate gene expression in the brain of honey bee Apis mellifera (Hymenoptera: Apidae) workers exposed to neonicotinoid imidacloprid. J Therm Biol 2020; 93:102696. [DOI: 10.1016/j.jtherbio.2020.102696] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 07/27/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022]
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16
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Tu N, Liang D, Zhang P. Whole-exome sequencing and genome-wide evolutionary analyses identify novel candidate genes associated with infrared perception in pit vipers. Sci Rep 2020; 10:13033. [PMID: 32747674 PMCID: PMC7400743 DOI: 10.1038/s41598-020-69843-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 07/14/2020] [Indexed: 12/17/2022] Open
Abstract
Pit vipers possess a unique thermal sensory system consisting of facial pits that allow them to detect minute temperature fluctuations within their environments. Biologists have long attempted to elucidate the genetic basis underlying the infrared perception of pit vipers. Early studies have shown that the TRPA1 gene is the thermal sensor associated with infrared detection in pit vipers. However, whether genes other than TRPA1 are also involved in the infrared perception of pit vipers remains unknown. Here, we sequenced the whole exomes of ten snake species and performed genome-wide evolutionary analyses to search for novel candidate genes that might be involved in the infrared perception of pit vipers. We applied both branch-length-comparison and selection-pressure-alteration analyses to identify genes that specifically underwent accelerated evolution in the ancestral lineage of pit vipers. A total of 47 genes were identified. These genes were significantly enriched in the ion transmembrane transporter, stabilization of membrane potential, and temperature gating activity functional categories. The expression levels of these candidate genes in relevant nerve tissues (trigeminal ganglion, dorsal root ganglion, midbrain, and cerebrum) were also investigated in this study. We further chose one of our candidate genes, the potassium channel gene KCNK4, as an example to discuss its possible role in the infrared perception of pit vipers. Our study provides the first genome-wide survey of infrared perception-related genes in pit vipers via comparative evolutionary analyses and reveals valuable candidate genes for future functional studies.
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Affiliation(s)
- Na Tu
- State Key Laboratory of Biocontrol, College of Ecology and Evolution, School of Life Sciences, Higher Education Mega Center, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Dan Liang
- State Key Laboratory of Biocontrol, College of Ecology and Evolution, School of Life Sciences, Higher Education Mega Center, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Peng Zhang
- State Key Laboratory of Biocontrol, College of Ecology and Evolution, School of Life Sciences, Higher Education Mega Center, Sun Yat-Sen University, Guangzhou, 510006, China.
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17
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Li LJ, Wang YB, Qu PF, Ma L, Liu K, Yang L, Nie SJ, Xi YM, Jia PL, Tang X, Sun ZC, Huang WL, Li YH, Dong Y, Lei PP. Genetic analysis of Yunnan sudden unexplained death by whole genome sequencing in Southwest of China. J Forensic Leg Med 2020; 70:101896. [PMID: 32090967 DOI: 10.1016/j.jflm.2020.101896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 12/03/2019] [Accepted: 01/05/2020] [Indexed: 11/16/2022]
Affiliation(s)
- Lan-Jiang Li
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
| | - Yue-Bing Wang
- Yunnan Institute of Endemic Disease Control and Prevention, Yunnan Province, China.
| | - Peng-Fei Qu
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
| | - Lin Ma
- Yunnan Institute of Endemic Disease Control and Prevention, Yunnan Province, China.
| | - Kai Liu
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
| | - Lin Yang
- Yunnan Institute of Endemic Disease Control and Prevention, Yunnan Province, China.
| | - Sheng-Jie Nie
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
| | - Yan-Mei Xi
- Yunnan Institute of Endemic Disease Control and Prevention, Yunnan Province, China.
| | - Peng-Lin Jia
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
| | - Xue Tang
- Yunnan Institute of Endemic Disease Control and Prevention, Yunnan Province, China.
| | - Zhong-Chun Sun
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
| | - Wen-Li Huang
- Yunnan Institute of Endemic Disease Control and Prevention, Yunnan Province, China.
| | - Yu-Hua Li
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
| | - Yi Dong
- Yunnan Institute of Endemic Disease Control and Prevention, Yunnan Province, China.
| | - Pu-Ping Lei
- Department of Forensic Medicine, Kunming Medical University, Yunnan Province, China.
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18
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Dierich M, van Ham WB, Stary‐Weinzinger A, Leitner MG. Histidine at position 462 determines the low quinine sensitivity of ether-à-go-go channel superfamily member K v 12.1. Br J Pharmacol 2019; 176:2708-2723. [PMID: 31032878 PMCID: PMC6609544 DOI: 10.1111/bph.14693] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 04/03/2019] [Accepted: 04/15/2019] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The ether-à-go-go (Eag) Kv superfamily comprises closely related Kv 10, Kv 11, and Kv 12 subunits. Kv 11.1 (termed hERG in humans) gained much attention, as drug-induced inhibition of these channels is a frequent cause of sudden death in humans. The exclusive drug sensitivity of Kv 11.1 can be explained by central drug-binding pockets that are absent in most other channels. Currently, it is unknown whether Kv 12 channels are equipped with an analogous drug-binding pocket and whether drug-binding properties are conserved in all Eag superfamily members. EXPERIMENTAL APPROACH We analysed sensitivity of recombinant Kv 12.1 channels to quinine, a substituted quinoline that blocks Kv 10.1 and Kv 11.1 at low micromolar concentrations. KEY RESULTS Quinine inhibited Kv 12.1, but its affinity was 10-fold lower than for Kv 11.1. Contrary to Kv 11.1, quinine inhibited Kv 12.1 in a largely voltage-independent manner and induced channel opening at more depolarised potentials. Low sensitivity of Kv 12.1 and characteristics of quinine-dependent inhibition were determined by histidine 462, as site-directed mutagenesis of this residue into the homologous tyrosine of Kv 11.1 conferred Kv 11.1-like quinine block to Kv 12.1(H462Y). Molecular modelling demonstrated that the low affinity of Kv 12.1 was determined by only weak interactions of residues in the central cavity with quinine. In contrast, more favourable interactions can explain the higher quinine sensitivity of Kv 12.1(H462Y) and Kv 11.1 channels. CONCLUSIONS AND IMPLICATIONS The quinoline-binding "motif" is not conserved within the Eag superfamily, although the overall architecture of these channels is apparently similar. Our findings highlight functional and pharmacological diversity in this group of evolutionary-conserved channels.
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Affiliation(s)
- Marlen Dierich
- Department of Neurophysiology, Institute of Physiology and PathophysiologyPhilipps‐University MarburgMarburgGermany
| | - Willem B. van Ham
- Department of Medical PhysiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
- Department of Pharmacology and ToxicologyUniversity of ViennaViennaAustria
| | | | - Michael G. Leitner
- Department of Neurophysiology, Institute of Physiology and PathophysiologyPhilipps‐University MarburgMarburgGermany
- Division of Physiology, Department of Physiology and Medical PhysicsMedical University of InnsbruckInnsbruckAustria
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19
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Dierich M, Leitner MG. K v12.1 channels are not sensitive to G qPCR-triggered activation of phospholipase Cβ. Channels (Austin) 2018; 12:228-239. [PMID: 30136882 PMCID: PMC6986784 DOI: 10.1080/19336950.2018.1475783] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Kv12.1 K+ channels are expressed in several brain areas, but no physiological function could be attributed to these subunits so far. As genetically-modified animal models are not available, identification of native Kv12.1 currents must rely on characterization of distinct channel properties. Recently, it was shown in Xenopus laevis oocytes that Kv12.1 channels were modulated by membrane PI(4,5)P2. However, it is not known whether these channels are also sensitive to physiologically-relevant PI(4,5)P2 dynamics. We thus studied whether Kv12.1 channels were modulated by activation of phospholipase C β (PLCβ) and found that they were insensitive to receptor-triggered depletion of PI(4,5)P2. Thus, Kv12.1 channels add to the growing list of K+ channels that are insensitive to PLCβ signaling, although modulated by PI(4,5)P2 in Xenopus laevis oocytes.
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Affiliation(s)
- Marlen Dierich
- a Department of Neurophysiology , Institute of Physiology and Pathophysiology, Philipps-University Marburg , Marburg , Germany
| | - Michael G Leitner
- a Department of Neurophysiology , Institute of Physiology and Pathophysiology, Philipps-University Marburg , Marburg , Germany.,b Division of Physiology, Department of Physiology and Medical Physics , Medical University of Innsbruck , Innsbruck , Austria
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20
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Genetic study links components of the autonomous nervous system to heart-rate profile during exercise. Nat Commun 2018; 9:898. [PMID: 29497042 PMCID: PMC5832790 DOI: 10.1038/s41467-018-03395-6] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 02/09/2018] [Indexed: 01/01/2023] Open
Abstract
Heart rate (HR) responds to exercise by increasing during exercise and recovering after exercise. As such, HR is an important predictor of mortality that researchers believe is modulated by the autonomic nervous system. However, the mechanistic basis underlying inter-individual differences has yet to be explained. Here, we perform a large-scale genome-wide analysis of HR increase and HR recovery in 58,818 UK Biobank individuals. Twenty-five independent SNPs in 23 loci are identified to be associated (p < 8.3 × 10−9) with HR increase or HR recovery. A total of 36 candidate causal genes are prioritized that are enriched for pathways related to neuron biology. No evidence is found of a causal relationship with mortality or cardiovascular diseases. However, a nominal association with parental lifespan requires further study. In conclusion, the findings provide new biological and clinical insight into the mechanistic underpinnings of HR response to exercise. The results also underscore the role of the autonomous nervous system in HR recovery. Response of the heart rate (HR) to exercise is associated with cardiac fitness and risk of cardiac death. Here, in a genome-wide association study, Verweij et al. identify 23 loci for HR increase during exercise or HR recovery, and highlight pleiotropy with blood pressure by polygenic risk score analysis.
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21
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Bauer CK, Schwarz JR. Ether-à-go-go K + channels: effective modulators of neuronal excitability. J Physiol 2018; 596:769-783. [PMID: 29333676 DOI: 10.1113/jp275477] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/18/2017] [Indexed: 12/22/2022] Open
Abstract
Mammalian ether-à-go-go (EAG) channels are voltage-gated K+ channels. They are encoded by the KCNH gene family and divided into three subfamilies, eag (Kv10), erg (eag-related gene; Kv11) and elk (eag-like; Kv12). All EAG channel subtypes are expressed in the brain where they effectively modulate neuronal excitability. This Topical Review describes the biophysical properties of each of the EAG channel subtypes, their function in neurons and the neurological diseases induced by EAG channel mutations. In contrast to the function of erg currents in the heart, where they contribute to repolarization of the cardiac action potential, erg currents in neurons are involved in the maintenance of the resting potential, setting of action potential threshold and frequency accommodation. They can even support high frequency firing by preventing a depolarization-induced Na+ channel block. EAG channels are modulated differentially, e.g. eag channels by intracellular Ca2+ , erg channels by extracellular K+ and GPCRs, and elk channels by changes in pH. So far, only currents mediated by erg channels have been recorded in neurons with the help of selective blockers. Neuronal eag and elk currents have not been isolated due to the lack of suitable channel blockers. However, findings in KO mice indicate a physiological role of eag1 currents in synaptic transmission and an involvement of elk2 currents in cognitive performance. Human eag1 and eag2 gain-of-function mutations underlie syndromes associated with epileptic seizures.
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Affiliation(s)
- Christiane K Bauer
- Department of Cellular and Integrative Physiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jürgen R Schwarz
- Institute of Molecular Neurogenetics, Center of Molecular Neurobiology Hamburg (ZMNH), University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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22
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Dierich M, Evers S, Wilke BU, Leitner MG. Inverse Modulation of Neuronal K v12.1 and K v11.1 Channels by 4-Aminopyridine and NS1643. Front Mol Neurosci 2018; 11:11. [PMID: 29440988 PMCID: PMC5797642 DOI: 10.3389/fnmol.2018.00011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 01/09/2018] [Indexed: 01/24/2023] Open
Abstract
The three members of the ether-à-go-go-gene-like (Elk; Kv12.1-Kv12.3) family of voltage-gated K+ channels are predominantly expressed in neurons, but only little information is available on their physiological relevance. It was shown that Kv12.2 channels modulate excitability of hippocampal neurons, but no native current could be attributed to Kv12.1 and Kv12.3 subunits yet. This may appear somewhat surprising, given high expression of their mRNA transcripts in several brain areas. Native Kv12 currents may have been overlooked so far due to limited knowledge on their biophysical properties and lack of specific pharmacology. Except for Kv12.2, appropriate genetically modified mouse models have not been described; therefore, identification of Kv12-mediated currents in native cell types must rely on characterization of unique properties of the channels. We focused on recombinant human Kv12.1 to identify distinct properties of these channels. We found that Kv12.1 channels exhibited significant mode shift of activation, i.e., stabilization of the voltage sensor domain in a “relaxed” open state after prolonged channel activation. This mode shift manifested by a slowing of deactivation and, most prominently, a significant shift of voltage dependence to hyperpolarized potentials. In contrast to related Kv11.1, mode shift was not sensitive to extracellular Na+, which allowed for discrimination between these isoforms. Sensitivity of Kv12.1 and Kv11.1 to the broad-spectrum K+ antagonist 4-aminopyridine was similar. However, 4-AP strongly activated Kv12.1 channels, but it was an inhibitor of Kv11 channels. Interestingly, the agonist of Kv11 channels NS1643 also differentially modulated the activity of these channels, i.e., NS1643 activated Kv11.1, but strongly inhibited Kv12.1 channels. Thus, these closely related channels are distinguished by inverse pharmacological profiles. In summary, we identified unique biophysical and pharmacological properties of Kv12.1 channels and established straightforward experimental protocols to characterize Kv12.1-mediated currents. Identification of currents in native cell types with mode shift that are activated through 4-AP and inhibited by NS1643 can provide strong evidence for contribution of Kv12.1 to whole cell currents.
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Affiliation(s)
- Marlen Dierich
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University of Marburg, Marburg, Germany
| | - Saskia Evers
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University of Marburg, Marburg, Germany
| | - Bettina U Wilke
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University of Marburg, Marburg, Germany
| | - Michael G Leitner
- Department of Neurophysiology, Institute of Physiology and Pathophysiology, Philipps University of Marburg, Marburg, Germany.,Division of Physiology, Department of Physiology and Medical Physics, Innsbruck Medical University, Innsbruck, Austria
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Lee BD, Gonzalez S, Villa E, Camarillo C, Rodriguez M, Yao Y, Guo W, Flores D, Jerez A, Raventos H, Ontiveros A, Nicolini H, Escamilla M. A genome-wide quantitative trait locus (QTL) linkage scan of NEO personality factors in Latino families segregating bipolar disorder. Am J Med Genet B Neuropsychiatr Genet 2017; 174:683-690. [PMID: 28556497 PMCID: PMC5597458 DOI: 10.1002/ajmg.b.32551] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 03/20/2017] [Accepted: 04/25/2017] [Indexed: 12/24/2022]
Abstract
Personality traits have been suggested as potential endophenotypes for Bipolar Disorder (BP), as they can be quantitatively measured and show correlations with BP. The present study utilized data from 2,745 individuals from 686 extended pedigrees originally ascertained for having multiplex cases of BP (963 cases of BPI or schizoaffective BP). Subjects were assessed with the NEO Personality Inventory, Revised (NEO PI-R) and genotyped using the Illumina HumanLinkage-24 Bead Chip, with an average genetic coverage of 0.67 cM. Two point linkage scores were calculated for each trait as a quantitative variable using SOLAR (Sequential Oligogenic Linkage Analysis Routines). Suggestive evidence for linkage was found for neuroticism at 1q32.1 (LOD = 2.52), 6q23.3 (2.32), 16p12 (2.79), extraversion at 4p15.3 (2.33), agreeableness at 4q31.1 (2.37), 5q34 (2.80), 7q31.1 (2.56), 16q22 (2.52), and conscientiousness at 4q31.1 (2.50). Each of the above traits have been shown to be correlated with the broad BP phenotype in this same sample. In addition, for the trait of openness, we found significant evidence of linkage to chromosome 3p24.3 (rs336610, LOD = 4.75) and suggestive evidence at 1q43 (2.74), 5q35.1 (3.03), 11q14.3 (2.61), 11q21 (2.30), and 19q13.1 (2.52). These findings support previous linkage findings of the openness trait to chromosome 19q13 and the agreeableness trait to 4q31 and identify a number of new loci for personality endophenotypes related to bipolar disorder.
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Affiliation(s)
- Byung Dae Lee
- Center of Excellence for Neurosciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas,Department of Psychiatry, School of Medicine, Pusan National University, Busan, South Korea
| | - Suzanne Gonzalez
- Center of Excellence for Neurosciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
| | - Erika Villa
- Center of Excellence for Neurosciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
| | - Cynthia Camarillo
- Center of Excellence for Neurosciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
| | - Marco Rodriguez
- Center of Excellence for Neurosciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas
| | - Yin Yao
- Unit on Statistical Genomics, National Institute of Mental Health, Bethesda, Maryland
| | - Wei Guo
- Unit on Statistical Genomics, National Institute of Mental Health, Bethesda, Maryland
| | - Deborah Flores
- Los Angeles Biomedical Research Center at Harbor, University of California Los Angeles Medical Center, Torrance, California
| | - Alvaro Jerez
- Centro Internacional de Trastornos Afectivos y de la Conducta Adictiva, Guatemala, Guatemala
| | - Henriette Raventos
- Centro de Investigacion en Biologia Celular y Molecular y Escuela de Biologia, Universidad de Costa Rica, San Jose, Costa Rica
| | - Alfonso Ontiveros
- Instituto de Informacion e InvestigaciónenSalud Mental AC, Monterrey, Nuevo Leon, Mexico
| | - Humberto Nicolini
- Grupo de Estudios Medicos y Familiares Carracci, S.C., Mexico, D.F., Mexico,Instituto Nacional de Medicina Genomica, Mexico, D.F., Mexico
| | - Michael Escamilla
- Center of Excellence for Neurosciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas,Department of Psychiatry, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas,Correspondence to: Michael Escamilla, MD, Department of Psychiatry Paul L. Foster School of Medicine Texas Tech University Health Science Center 4800 Alberta El Paso, TX 79905, USA,
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24
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Jiménez-Vargas JM, Possani LD, Luna-Ramírez K. Arthropod toxins acting on neuronal potassium channels. Neuropharmacology 2017; 127:139-160. [PMID: 28941737 DOI: 10.1016/j.neuropharm.2017.09.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 01/01/2023]
Abstract
Arthropod venoms are a rich mixture of biologically active compounds exerting different physiological actions across diverse phyla and affecting multiple organ systems including the central nervous system. Venom compounds can inhibit or activate ion channels, receptors and transporters with high specificity and affinity providing essential insights into ion channel function. In this review, we focus on arthropod toxins (scorpions, spiders, bees and centipedes) acting on neuronal potassium channels. A brief description of the K+ channels classification and structure is included and a compendium of neuronal K+ channels and the arthropod toxins that modify them have been listed. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Juana María Jiménez-Vargas
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Lourival D Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Karen Luna-Ramírez
- Illawarra Health and Medical Research Institute, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia.
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25
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Sigurdsson MI, Saddic L, Heydarpour M, Chang TW, Shekar P, Aranki S, Couper GS, Shernan SK, Muehlschlegel JD, Body SC. Post-operative atrial fibrillation examined using whole-genome RNA sequencing in human left atrial tissue. BMC Med Genomics 2017; 10:25. [PMID: 28464817 PMCID: PMC5414158 DOI: 10.1186/s12920-017-0270-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 04/25/2017] [Indexed: 01/02/2023] Open
Abstract
Background Both ambulatory atrial fibrillation (AF) and post-operative AF (poAF) are associated with substantial morbidity and mortality. Analyzing the tissue-specific gene expression in the left atrium (LA) can identify novel genes associated with AF and further the understanding of the mechanism by which previously identified genetic variants associated with AF mediate their effects. Methods LA free wall samples were obtained intraoperatively immediately prior to mitral valve surgery in 62 Caucasian individuals. Gene expression was quantified on mRNA harvested from these samples using RNA sequencing. An expression quantitative trait loci (eQTL) analysis was performed, comparing gene expression between different genotypes of 1.0 million genetic markers, emphasizing genomic regions and genes associated with AF. Results Comparison of whole-genome expression between patients who later developed poAF and those who did not identified 23 differentially expressed genes. These included genes associated with the resting membrane potential modified by potassium currents, as well as genes within Wnt signaling and cyclic GMP metabolism. The eQTL analysis identified 16,139 cis eQTL relationships in the LA, including several involving genes and single nucleotide polymorphisms (SNPs) linked to AF. A previous relationship between rs3744029 and MYOZ1 expression was confirmed, and a novel relationship between rs6795970 and the expression of the SCN10A gene was identified. Conclusions The current study is the first analysis of the human LA expression landscape using high-throughput RNA sequencing. Several novel genes and variants likely involved in AF pathogenesis were identified, thus furthering the understanding of how variants associated with AF mediate their effects via altered gene expression. Trial registration ClinicalTrials.gov ID: NCT00833313, registered 5. January 2009 Electronic supplementary material The online version of this article (doi:10.1186/s12920-017-0270-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martin I Sigurdsson
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA.
| | - Louis Saddic
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Mahyar Heydarpour
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Tzuu-Wang Chang
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Prem Shekar
- Division of Cardiac Surgery, Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, MA, USA
| | - Sary Aranki
- Division of Cardiac Surgery, Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, MA, USA
| | - Gregory S Couper
- Division of Cardiac Surgery, Department of Surgery, Brigham and Women's Hospital/Harvard Medical School, Boston, MA, USA
| | - Stanton K Shernan
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Jochen D Muehlschlegel
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
| | - Simon C Body
- Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital/Harvard Medical School, 75 Francis Street, Boston, MA, 02115, USA
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26
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Dai G, Zagotta WN. Molecular mechanism of voltage-dependent potentiation of KCNH potassium channels. eLife 2017; 6. [PMID: 28443815 PMCID: PMC5440166 DOI: 10.7554/elife.26355] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 04/24/2017] [Indexed: 12/11/2022] Open
Abstract
EAG-like (ELK) voltage-gated potassium channels are abundantly expressed in the brain. These channels exhibit a behavior called voltage-dependent potentiation (VDP), which appears to be a specialization to dampen the hyperexitability of neurons. VDP manifests as a potentiation of current amplitude, hyperpolarizing shift in voltage sensitivity, and slowing of deactivation in response to a depolarizing prepulse. Here we show that VDP of D. rerio ELK channels involves the structural interaction between the intracellular N-terminal eag domain and C-terminal CNBHD. Combining transition metal ion FRET, patch-clamp fluorometry, and incorporation of a fluorescent noncanonical amino acid, we show that there is a rearrangement in the eag domain-CNBHD interaction with the kinetics, voltage-dependence, and ATP-dependence of VDP. We propose that the activation of ELK channels involves a slow open-state dependent rearrangement of the direct interaction between the eag domain and CNBHD, which stabilizes the opening of the channel. DOI:http://dx.doi.org/10.7554/eLife.26355.001 In humans and other animals, electrical signals trigger the heart to beat and carry information around the brain and nervous system. Particular cells can generate these signals by regulating the flow of ions into and out of the cell via proteins called ion channels. These proteins sit in the membrane that surrounds the cell and will open or close in response to specific signals. For example, an ion channel in humans called hERG allows positively-charged potassium ions to flow out of a heart cell to help the cell return to its “resting” state after producing an electrical signal. Defects in hERG can alter the rhythm at which the heart beats, leading to a serious condition called Long QT syndrome. The human hERG channel is part of a family of related channels known as the KCNH channels. These channels are made of four protein subunits that assemble to form a pore that spans the cell membrane. When a cell is resting before producing an electrical signal, KCNH channels are generally closed. However, once an electrical signal starts, the flow of ions through other ion channels in the cell membrane changes an electrical property across the membrane known as the “voltage”. This change in voltage causes KCNH channels to open. Dai and Zagotta studied how a KCNH channel known as ELK from zebrafish responds to changes in membrane voltage. The experiments show that the manner in which ELK channels respond to the voltage is due to changes in how the subunits interact in the part of the channel that lies inside the cell. Further experiments using several new techniques reveal in much more detail how the shape of the channel alters as the voltage changes. These new techniques could also be used to observe how other KCNH channels in the heart and brain change shape in response to changes in voltage. This could lead to the design of new drugs to treat heart and neurological diseases. DOI:http://dx.doi.org/10.7554/eLife.26355.002
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Affiliation(s)
- Gucan Dai
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
| | - William N Zagotta
- Department of Physiology and Biophysics, University of Washington, Seattle, United States
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27
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Li X, Anishkin A, Liu H, van Rossum DB, Chintapalli SV, Sassic JK, Gallegos D, Pivaroff-Ward K, Jegla T. Bimodal regulation of an Elk subfamily K+ channel by phosphatidylinositol 4,5-bisphosphate. ACTA ACUST UNITED AC 2016; 146:357-74. [PMID: 26503718 PMCID: PMC4621751 DOI: 10.1085/jgp.201511491] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PIP2 mediates the bimodal regulation of the EAG family K+ channel ELK1 to produce an overall inhibitory effect. Phosphatidylinositol 4,5-bisphosphate (PIP2) regulates Shaker K+ channels and voltage-gated Ca2+ channels in a bimodal fashion by inhibiting voltage activation while stabilizing open channels. Bimodal regulation is conserved in hyperpolarization-activated cyclic nucleotide–gated (HCN) channels, but voltage activation is enhanced while the open channel state is destabilized. The proposed sites of PIP2 regulation in these channels include the voltage-sensor domain (VSD) and conserved regions of the proximal cytoplasmic C terminus. Relatively little is known about PIP2 regulation of Ether-á-go-go (EAG) channels, a metazoan-specific family of K+ channels that includes three gene subfamilies, Eag (Kv10), Erg (Kv11), and Elk (Kv12). We examined PIP2 regulation of the Elk subfamily potassium channel human Elk1 to determine whether bimodal regulation is conserved within the EAG K+ channel family. Open-state stabilization by PIP2 has been observed in human Erg1, but the proposed site of regulation in the distal C terminus is not conserved among EAG family channels. We show that PIP2 strongly inhibits voltage activation of Elk1 but also stabilizes the open state. This stabilization produces slow deactivation and a mode shift in voltage gating after activation. However, removal of PIP2 has the net effect of enhancing Elk1 activation. R347 in the linker between the VSD and pore (S4–S5 linker) and R479 near the S6 activation gate are required for PIP2 to inhibit voltage activation. The ability of PIP2 to stabilize the open state also requires these residues, suggesting an overlap in sites central to the opposing effects of PIP2 on channel gating. Open-state stabilization in Elk1 requires the N-terminal eag domain (PAS domain + Cap), and PIP2-dependent stabilization is enhanced by a conserved basic residue (K5) in the Cap. Our data shows that PIP2 can bimodally regulate voltage gating in EAG family channels, as has been proposed for Shaker and HCN channels. PIP2 regulation appears fundamentally different for Elk and KCNQ channels, suggesting that, although both channel types can regulate action potential threshold in neurons, they are not functionally redundant.
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Affiliation(s)
- Xiaofan Li
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Andriy Anishkin
- Department of Biology, University of Maryland, College Park, MD 20742
| | - Hansi Liu
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Damian B van Rossum
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Sree V Chintapalli
- Arkansas Children's Nutrition Center and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202 Arkansas Children's Nutrition Center and Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72202
| | - Jessica K Sassic
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - David Gallegos
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
| | - Kendra Pivaroff-Ward
- Department of Earth and Space Sciences, University of Washington, Seattle, WA 98195
| | - Timothy Jegla
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802 Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802
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28
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Li X, Martinson AS, Layden MJ, Diatta FH, Sberna AP, Simmons DK, Martindale MQ, Jegla TJ. Ether-à-go-go family voltage-gated K+ channels evolved in an ancestral metazoan and functionally diversified in a cnidarian-bilaterian ancestor. ACTA ACUST UNITED AC 2015; 218:526-36. [PMID: 25696816 DOI: 10.1242/jeb.110080] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
We examined the evolutionary origins of the ether-à-go-go (EAG) family of voltage-gated K(+) channels, which have a strong influence on the excitability of neurons. The bilaterian EAG family comprises three gene subfamilies (Eag, Erg and Elk) distinguished by sequence conservation and functional properties. Searches of genome sequence indicate that EAG channels are metazoan specific, appearing first in ctenophores. However, phylogenetic analysis including two EAG family channels from the ctenophore Mnemiopsis leidyi indicates that the diversification of the Eag, Erg and Elk gene subfamilies occurred in a cnidarian/bilaterian ancestor after divergence from ctenophores. Erg channel function is highly conserved between cnidarians and mammals. Here we show that Eag and Elk channels from the sea anemone Nematostella vectensis (NvEag and NvElk) also share high functional conservation with mammalian channels. NvEag, like bilaterian Eag channels, has rapid kinetics, whereas NvElk activates at extremely hyperpolarized voltages, which is characteristic of Elk channels. Potent inhibition of voltage activation by extracellular protons is conserved between mammalian and Nematostella EAG channels. However, characteristic inhibition of voltage activation by Mg(2+) in Eag channels and Ca(2+) in Erg channels is reduced in Nematostella because of mutation of a highly conserved aspartate residue in the voltage sensor. This mutation may preserve sub-threshold activation of Nematostella Eag and Erg channels in a high divalent cation environment. mRNA in situ hybridization of EAG channels in Nematostella suggests that they are differentially expressed in distinct cell types. Most notable is the expression of NvEag in cnidocytes, a cnidarian-specific stinging cell thought to be a neuronal subtype.
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Affiliation(s)
- Xiaofan Li
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Alexandra S Martinson
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Michael J Layden
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32136, USA
| | - Fortunay H Diatta
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Anna P Sberna
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - David K Simmons
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32136, USA
| | - Mark Q Martindale
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32136, USA
| | - Timothy J Jegla
- Department of Biology and Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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29
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The conservation and signatures of lincRNAs in Marek's disease of chicken. Sci Rep 2015; 5:15184. [PMID: 26471251 PMCID: PMC4608010 DOI: 10.1038/srep15184] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 09/15/2015] [Indexed: 01/10/2023] Open
Abstract
Long intergenic non-coding RNAs (lincRNAs) associated with a number of cancers and other diseases have been identified in mammals, but they are still formidable to be comprehensively identified and characterized. Marek's disease (MD) is a T cell lymphoma of chickens induced by Marek's disease virus (MDV). Here, we used a MD chicken model to develop a precise pipeline for identifying lincRNAs and to determine the roles of lincRNAs in T cell tumorigenesis. More than 1,000 lincRNA loci were identified in chicken bursa. Computational analyses demonstrated that lincRNAs are conserved among different species such as human, mouse and chicken. The putative lincRNAs were found to be associated with a wide range of biological functions including immune responses. Interestingly, we observed distinct lincRNA expression signatures in bursa between MD resistant and susceptible lines of chickens. One of the candidate lincRNAs, termed linc-satb1, was found to play a crucial role in MD immune response by regulating a nearby protein-coding gene SATB1. Thus, our results manifested that lincRNAs may exert considerable influence on MDV-induced T cell tumorigenesis and provide a rich resource for hypothesis-driven functional studies to reveal genetic mechanisms underlying susceptibility to tumorigenesis.
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Major diversification of voltage-gated K+ channels occurred in ancestral parahoxozoans. Proc Natl Acad Sci U S A 2015; 112:E1010-9. [PMID: 25691740 DOI: 10.1073/pnas.1422941112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We examined the origins and functional evolution of the Shaker and KCNQ families of voltage-gated K(+) channels to better understand how neuronal excitability evolved. In bilaterians, the Shaker family consists of four functionally distinct gene families (Shaker, Shab, Shal, and Shaw) that share a subunit structure consisting of a voltage-gated K(+) channel motif coupled to a cytoplasmic domain that mediates subfamily-exclusive assembly (T1). We traced the origin of this unique Shaker subunit structure to a common ancestor of ctenophores and parahoxozoans (cnidarians, bilaterians, and placozoans). Thus, the Shaker family is metazoan specific but is likely to have evolved in a basal metazoan. Phylogenetic analysis suggested that the Shaker subfamily could predate the divergence of ctenophores and parahoxozoans, but that the Shab, Shal, and Shaw subfamilies are parahoxozoan specific. In support of this, putative ctenophore Shaker subfamily channel subunits coassembled with cnidarian and mouse Shaker subunits, but not with cnidarian Shab, Shal, or Shaw subunits. The KCNQ family, which has a distinct subunit structure, also appears solely within the parahoxozoan lineage. Functional analysis indicated that the characteristic properties of Shaker, Shab, Shal, Shaw, and KCNQ currents evolved before the divergence of cnidarians and bilaterians. These results show that a major diversification of voltage-gated K(+) channels occurred in ancestral parahoxozoans and imply that many fundamental mechanisms for the regulation of action potential propagation evolved at this time. Our results further suggest that there are likely to be substantial differences in the regulation of neuronal excitability between ctenophores and parahoxozoans.
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Kanageswaran N, Demond M, Nagel M, Schreiner BSP, Baumgart S, Scholz P, Altmüller J, Becker C, Doerner JF, Conrad H, Oberland S, Wetzel CH, Neuhaus EM, Hatt H, Gisselmann G. Deep sequencing of the murine olfactory receptor neuron transcriptome. PLoS One 2015; 10:e0113170. [PMID: 25590618 PMCID: PMC4295871 DOI: 10.1371/journal.pone.0113170] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 10/25/2014] [Indexed: 11/18/2022] Open
Abstract
The ability of animals to sense and differentiate among thousands of odorants relies on a large set of olfactory receptors (OR) and a multitude of accessory proteins within the olfactory epithelium (OE). ORs and related signaling mechanisms have been the subject of intensive studies over the past years, but our knowledge regarding olfactory processing remains limited. The recent development of next generation sequencing (NGS) techniques encouraged us to assess the transcriptome of the murine OE. We analyzed RNA from OEs of female and male adult mice and from fluorescence-activated cell sorting (FACS)-sorted olfactory receptor neurons (ORNs) obtained from transgenic OMP-GFP mice. The Illumina RNA-Seq protocol was utilized to generate up to 86 million reads per transcriptome. In OE samples, nearly all OR and trace amine-associated receptor (TAAR) genes involved in the perception of volatile amines were detectably expressed. Other genes known to participate in olfactory signaling pathways were among the 200 genes with the highest expression levels in the OE. To identify OE-specific genes, we compared olfactory neuron expression profiles with RNA-Seq transcriptome data from different murine tissues. By analyzing different transcript classes, we detected the expression of non-olfactory GPCRs in ORNs and established an expression ranking for GPCRs detected in the OE. We also identified other previously undescribed membrane proteins as potential new players in olfaction. The quantitative and comprehensive transcriptome data provide a virtually complete catalogue of genes expressed in the OE and present a useful tool to uncover candidate genes involved in, for example, olfactory signaling, OR trafficking and recycling, and proliferation.
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Affiliation(s)
| | - Marilen Demond
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
- University Duisburg-Essen, Institute of Medical Radiation Biology, Essen, Germany
| | - Maximilian Nagel
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | | | - Sabrina Baumgart
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Paul Scholz
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | | | | | - Julia F. Doerner
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Heike Conrad
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
- Cluster of Excellence and DFG Research Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
| | - Sonja Oberland
- Pharmacology and Toxicology, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian H. Wetzel
- University of Regensburg, Department of Psychiatry and Psychotherapy, Molecular Neurosciences, Regensburg, Germany
| | - Eva M. Neuhaus
- Pharmacology and Toxicology, University Hospital Jena, Drackendorfer Str. 1, 07747 Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Hanns Hatt
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
| | - Günter Gisselmann
- Ruhr-University Bochum, Department of Cell Physiology, Bochum, Germany
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Thomson SJ, Hansen A, Sanguinetti MC. Concerted all-or-none subunit interactions mediate slow deactivation of human ether-à-go-go-related gene K+ channels. J Biol Chem 2014; 289:23428-36. [PMID: 25008322 DOI: 10.1074/jbc.m114.582437] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During the repolarization phase of a cardiac action potential, hERG1 K(+) channels rapidly recover from an inactivated state then slowly deactivate to a closed state. The resulting resurgence of outward current terminates the plateau phase and is thus a key regulator of action potential duration of cardiomyocytes. The intracellular N-terminal domain of the hERG1 subunit is required for slow deactivation of the channel as its removal accelerates deactivation 10-fold. Here we investigate the stoichiometry of hERG1 channel deactivation by characterizing the kinetic properties of concatenated tetramers containing a variable number of wild-type and mutant subunits. Three mutations known to accelerate deactivation were investigated, including R56Q and R4A/R5A in the N terminus and F656I in the S6 transmembrane segment. In all cases, a single mutant subunit induced the same rapid deactivation of a concatenated channel as that observed for homotetrameric mutant channels. We conclude that slow deactivation gating of hERG1 channels involves a concerted, fully cooperative interaction between all four wild-type channel subunits.
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Affiliation(s)
- Steven J Thomson
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute and
| | - Angela Hansen
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute and
| | - Michael C Sanguinetti
- From the Nora Eccles Harrison Cardiovascular Research and Training Institute and Department of Internal Medicine and Division of Cardiovascular Medicine, University of Utah, Salt Lake City, Utah 84112
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Kazmierczak M, Zhang X, Chen B, Mulkey DK, Shi Y, Wagner PG, Pivaroff-Ward K, Sassic JK, Bayliss DA, Jegla T. External pH modulates EAG superfamily K+ channels through EAG-specific acidic residues in the voltage sensor. ACTA ACUST UNITED AC 2013; 141:721-35. [PMID: 23712551 PMCID: PMC3664700 DOI: 10.1085/jgp.201210938] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The Ether-a-go-go (EAG) superfamily of voltage-gated K+ channels consists of three functionally distinct gene families (Eag, Elk, and Erg) encoding a diverse set of low-threshold K+ currents that regulate excitability in neurons and muscle. Previous studies indicate that external acidification inhibits activation of three EAG superfamily K+ channels, Kv10.1 (Eag1), Kv11.1 (Erg1), and Kv12.1 (Elk1). We show here that Kv10.2, Kv12.2, and Kv12.3 are similarly inhibited by external protons, suggesting that high sensitivity to physiological pH changes is a general property of EAG superfamily channels. External acidification depolarizes the conductance–voltage (GV) curves of these channels, reducing low threshold activation. We explored the mechanism of this high pH sensitivity in Kv12.1, Kv10.2, and Kv11.1. We first examined the role of acidic voltage sensor residues that mediate divalent cation block of voltage activation in EAG superfamily channels because protons reduce the sensitivity of Kv12.1 to Zn2+. Low pH similarly reduces Mg2+ sensitivity of Kv10.1, and we found that the pH sensitivity of Kv11.1 was greatly attenuated at 1 mM Ca2+. Individual neutralizations of a pair of EAG-specific acidic residues that have previously been implicated in divalent block of diverse EAG superfamily channels greatly reduced the pH response in Kv12.1, Kv10.2, and Kv11.1. Our results therefore suggest a common mechanism for pH-sensitive voltage activation in EAG superfamily channels. The EAG-specific acidic residues may form the proton-binding site or alternatively are required to hold the voltage sensor in a pH-sensitive conformation. The high pH sensitivity of EAG superfamily channels suggests that they could contribute to pH-sensitive K+ currents observed in vivo.
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Affiliation(s)
- Marcin Kazmierczak
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
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González C, Baez-Nieto D, Valencia I, Oyarzún I, Rojas P, Naranjo D, Latorre R. K(+) channels: function-structural overview. Compr Physiol 2013; 2:2087-149. [PMID: 23723034 DOI: 10.1002/cphy.c110047] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Potassium channels are particularly important in determining the shape and duration of the action potential, controlling the membrane potential, modulating hormone secretion, epithelial function and, in the case of those K(+) channels activated by Ca(2+), damping excitatory signals. The multiplicity of roles played by K(+) channels is only possible to their mammoth diversity that includes at present 70 K(+) channels encoding genes in mammals. Today, thanks to the use of cloning, mutagenesis, and the more recent structural studies using x-ray crystallography, we are in a unique position to understand the origins of the enormous diversity of this superfamily of ion channels, the roles they play in different cell types, and the relations that exist between structure and function. With the exception of two-pore K(+) channels that are dimers, voltage-dependent K(+) channels are tetrameric assemblies and share an extremely well conserved pore region, in which the ion-selectivity filter resides. In the present overview, we discuss in the function, localization, and the relations between function and structure of the five different subfamilies of K(+) channels: (a) inward rectifiers, Kir; (b) four transmembrane segments-2 pores, K2P; (c) voltage-gated, Kv; (d) the Slo family; and (e) Ca(2+)-activated SK family, SKCa.
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Affiliation(s)
- Carlos González
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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Manteniotis S, Lehmann R, Flegel C, Vogel F, Hofreuter A, Schreiner BSP, Altmüller J, Becker C, Schöbel N, Hatt H, Gisselmann G. Comprehensive RNA-Seq expression analysis of sensory ganglia with a focus on ion channels and GPCRs in Trigeminal ganglia. PLoS One 2013; 8:e79523. [PMID: 24260241 PMCID: PMC3832644 DOI: 10.1371/journal.pone.0079523] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/02/2013] [Indexed: 12/14/2022] Open
Abstract
The specific functions of sensory systems depend on the tissue-specific expression of genes that code for molecular sensor proteins that are necessary for stimulus detection and membrane signaling. Using the Next Generation Sequencing technique (RNA-Seq), we analyzed the complete transcriptome of the trigeminal ganglia (TG) and dorsal root ganglia (DRG) of adult mice. Focusing on genes with an expression level higher than 1 FPKM (fragments per kilobase of transcript per million mapped reads), we detected the expression of 12984 genes in the TG and 13195 in the DRG. To analyze the specific gene expression patterns of the peripheral neuronal tissues, we compared their gene expression profiles with that of the liver, brain, olfactory epithelium, and skeletal muscle. The transcriptome data of the TG and DRG were scanned for virtually all known G-protein-coupled receptors (GPCRs) as well as for ion channels. The expression profile was ranked with regard to the level and specificity for the TG. In total, we detected 106 non-olfactory GPCRs and 33 ion channels that had not been previously described as expressed in the TG. To validate the RNA-Seq data, in situ hybridization experiments were performed for several of the newly detected transcripts. To identify differences in expression profiles between the sensory ganglia, the RNA-Seq data of the TG and DRG were compared. Among the differentially expressed genes (> 1 FPKM), 65 and 117 were expressed at least 10-fold higher in the TG and DRG, respectively. Our transcriptome analysis allows a comprehensive overview of all ion channels and G protein-coupled receptors that are expressed in trigeminal ganglia and provides additional approaches for the investigation of trigeminal sensing as well as for the physiological and pathophysiological mechanisms of pain.
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36
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Structure of the carboxy-terminal region of a KCNH channel. Nature 2012; 481:530-3. [PMID: 22230959 PMCID: PMC3267858 DOI: 10.1038/nature10735] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2011] [Accepted: 11/23/2011] [Indexed: 11/15/2022]
Abstract
The KCNH family of ion channels, comprising ether-à-go-go (EAG), EAG-related gene (ERG), and EAG-like (ELK) K+ channel subfamilies, is crucial for repolarization of the cardiac action potential1, regulation of neuronal excitability2, and proliferation of tumor cells3. The C-terminal region of KCNH channels contains a cyclic nucleotide-binding homology domain (CNBHD) and C-linker that couples the CNBHD to the pore4. The C-linker/CNBHD is essential for proper function and trafficking of ion channels in the KCNH family5–9. However, despite the importance of the C-linker/CNBHD for the function of KCNH channels, the structural basis of ion channel regulation by the C-linker/CNBHD is unknown. Here we report the crystal structure of the C-linker/CNBHD of zebrafish ELK channels at 2.2 Å resolution. While the overall structure of the C-linker/CNBHD of zELK channels is similar to the cyclic nucleotide-binding domain (CNBD) structure of the related HCN channels10, there are dramatic differences. Unlike the CNBD of HCN, the CNBHD of zELK displays a negatively charged electrostatic profile that explains the lack of binding and regulation of KCNH channels by cyclic nucleotides4,11. Instead of cyclic nucleotide, the binding pocket is occupied by a short β-strand. Mutations of the β-strand shift the voltage dependence of activation to more depolarized voltages, implicating the β-strand as an intrinsic ligand for the CNBHD of zELK channels. In both zELK and HCN channels the C-linker is the site of virtually all of the intersubunit interactions in the C-terminal region. However, in the zELK structure there is a reorientation in the C-linker so the subunits form dimers instead of tetramers as observed in HCN channels. These results provide a structural framework for understanding the regulation of ion channels in the KCNH family by the C-linker/CNBHD and may guide the design of specific drugs.
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Bouchard C, Sarzynski MA, Rice TK, Kraus WE, Church TS, Sung YJ, Rao DC, Rankinen T. Genomic predictors of the maximal O₂ uptake response to standardized exercise training programs. J Appl Physiol (1985) 2010; 110:1160-70. [PMID: 21183627 DOI: 10.1152/japplphysiol.00973.2010] [Citation(s) in RCA: 270] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Low cardiorespiratory fitness is a powerful predictor of morbidity and cardiovascular mortality. In 473 sedentary adults, all whites, from 99 families of the Health, Risk Factors, Exercise Training, and Genetics (HERITAGE) Family Study, the heritability of gains in maximal O(2) uptake (VO(2max)) after exposure to a standardized 20-wk exercise program was estimated at 47%. A genome-wide association study based on 324,611 single-nucleotide polymorphisms (SNPs) was undertaken to identify SNPs associated with improvements in VO(2max) Based on single-SNP analysis, 39 SNPs were associated with the gains with P < 1.5 × 10(-4). Stepwise multiple regression analysis of the 39 SNPs identified a panel of 21 SNPs that accounted for 49% of the variance in VO(2max) trainability. Subjects who carried ≤9 favorable alleles at these 21 SNPs improved their VO(2max) by 221 ml/min, whereas those who carried ≥19 of these alleles gained, on average, 604 ml/min. The strongest association was with rs6552828, located in the acyl-CoA synthase long-chain member 1 (ACSL1) gene, which accounted by itself for ~6% of the training response of VO(2max). The genes nearest to the SNPs that were the strongest predictors were PR domain-containing 1 with ZNF domain (PRDM1); glutamate receptor, ionotropic, N-methyl-D-aspartate 3A (GRIN3A); K(+) channel, voltage gated, subfamily H, member 8 (KCNH8); and zinc finger protein of the cerebellum 4 (ZIC4). The association with the SNP nearest to ZIC4 was replicated in 40- to 65-yr-old, sedentary, overweight, and dyslipidemic subjects trained in Studies of a Targeted Risk Reduction Intervention Through Defined Exercise (STRRIDE; n = 183). Two SNPs were replicated in sedentary obese white women exercise trained in the Dose Response to Exercise (DREW) study (n = 112): rs1956197 near dishevelled associated activator of morphogenesis 1 (DAAM1) and rs17117533 in the vicinity of necdin (NDN). The association of SNPs rs884736 in the calmodulin-binding transcription activator 1 (CAMTA1) locus and rs17581162 ~68 kb upstream from regulator of G protein signaling 18 (RGS18) with the gains in VO(2max) in HERITAGE whites were replicated in HERITAGE blacks (n = 247). These genomic predictors of the response of Vo(2max) to regular exercise provide new targets for the study of the biology of fitness and its adaptation to regular exercise. Large-scale replication studies are warranted.
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Affiliation(s)
- Claude Bouchard
- Human Genomics Laboratory, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
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Peng JX, Xie JL, Zhou L, Hong YH, Gui JF. Evolutionary conservation of Dazl genomic organization and its continuous and dynamic distribution throughout germline development in gynogenetic gibel carp. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2010; 312:855-71. [PMID: 19504540 DOI: 10.1002/jez.b.21301] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
To investigate germline development and germ cell specification, we identified a Dazl homolog (CagDazl) from gynogenetic gibel carp (Carassius auratus gibelio). Its cDNA sequence and BAC clone sequence analyses revealed the genomic organization conservation and conserved synteny of the Dazl family members and their neighborhood genes among vertebrates, especially in fish. Moreover, a polyclonal antibody specific to CagDazl was produced and used to examine its expression and distribution throughout germline development at protein level. Firstly, ovary-specific expression pattern of CagDazl was confirmed in adult tissues by RT-PCR and Western blot. In addition, in situ hybridization and immunofluorescence localization demonstrated its specific expression in germ cells, and both its transcript and protein were localized to germ plasm. Then, co-localization of CagDazl and mitochondrial cloud was found, confirming that CagDazl transcript and its protein are germ plasm component and move via METRO pathway during oogenesis. Furthermore, the CagDazl is abundant and continuous throughout germline development and germ cell specification including primordial germ cell (PGC) formation, oogonium differentiation, oocyte development, and embryogenesis, and the dynamic distribution occurs at different development stages. The data suggest that maternal CagDazl might play an important role in gibel carp PGC formation. Therefore, CagDazl is a useful and specific marker for tracing germ plasm and germ cell development in the gynogenetic gibel carp. In addition, in comparison with previous studies in sexual reproduction species, the continuous and dynamic distribution of CagDazl protein in the germ plasm throughout the life cycle seems to have significant implication in sex evolution of vertebrates.
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Affiliation(s)
- Jin-Xia Peng
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Wuhan, China
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39
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Zhang X, Bursulaya B, Lee CC, Chen B, Pivaroff K, Jegla T. Divalent cations slow activation of EAG family K+ channels through direct binding to S4. Biophys J 2009; 97:110-20. [PMID: 19580749 DOI: 10.1016/j.bpj.2009.04.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 04/14/2009] [Accepted: 04/15/2009] [Indexed: 10/20/2022] Open
Abstract
Voltage-gated K+ channels share a common voltage sensor domain (VSD) consisting of four transmembrane helices, including a highly mobile S4 helix that contains the major gating charges. Activation of ether-a-go-go (EAG) family K+ channels is sensitive to external divalent cations. We show here that divalent cations slow the activation rate of two EAG family channels (Kv12.1 and Kv10.2) by forming a bridge between a residue in the S4 helix and acidic residues in S2. Histidine 328 in the S4 of Kv12.1 favors binding of Zn2+ and Cd2+, whereas the homologous residue Serine 321 in Kv10.2 contributes to effects of Mg2+ and Ni2+. This novel finding provides structural constraints for the position of transmembrane VSD helices in closed, ion-bound EAG family channels. Homology models of Kv12.1 and Kv10.2 VSD structures based on a closed-state model of the Shaker family K+ channel Kv1.2 match these constraints. Our results suggest close conformational conservation between closed EAG and Shaker family channels, despite large differences in voltage sensitivity, activation rates, and activation thresholds.
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Affiliation(s)
- Xiaofei Zhang
- Department of Cell Biology, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California 92037, USA
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40
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Noma K, Kimura K, Minatohara K, Nakashima H, Nagao Y, Mizoguchi A, Fujiyoshi Y. Triple N-glycosylation in the long S5-P loop regulates the activation and trafficking of the Kv12.2 potassium channel. J Biol Chem 2009; 284:33139-50. [PMID: 19808681 DOI: 10.1074/jbc.m109.021519] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mammalian voltage-dependent potassium (Kv) channels regulate the excitability of nerve and muscle cells. Kv12.2 features the longest S5-P loop among all known mammalian Kv channels with the most N-linked glycosylation sites (three sites). Despite its unique structural features, Kv12.2 is not well characterized. Because glycosylation plays important roles in the folding, trafficking, and function of various Kv channels, we focused on the N-glycosylation of Kv12.2. We show that Kv12.2 is N-glycosylated in Chinese hamster ovary (CHO) cells and in cultured neurons as well as in the mouse brain. As an effect of N-glycosylation on the function of Kv12.2, we demonstrate that removal of sugar chains causes a depolarizing shift in the steady-state activation without a significant reduction in current amplitude. Unlike the previously reported shift for Shaker-type Kv channels, this shift does not appear to be due to negatively charged sialic acid residues in the sugar chains. We next examined the trafficking in CHO cells to address whether the unglycosylated Kv12.2 channels are utilized in vivo. Although double mutants, retaining only one glycosylation site, are trafficked to the surface of CHO cells irrespective of the position of the glycosylated site, unglycosylated channels are not trafficked to the cell surface. Furthermore, we could not detect unglycosylated channels in the mouse brain. Our data suggest that only glycosylated Kv12.2 channels show proper voltage dependence and are utilized in vivo.
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Affiliation(s)
- Kentaro Noma
- Department of Biophysics, Graduate School of Science, Kyoto University, Oiwake, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
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Clancy SM, Chen B, Bertaso F, Mamet J, Jegla T. KCNE1 and KCNE3 beta-subunits regulate membrane surface expression of Kv12.2 K(+) channels in vitro and form a tripartite complex in vivo. PLoS One 2009; 4:e6330. [PMID: 19623261 PMCID: PMC2710002 DOI: 10.1371/journal.pone.0006330] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2009] [Accepted: 06/17/2009] [Indexed: 01/14/2023] Open
Abstract
Voltage-gated potassium channels that activate near the neuronal resting membrane potential are important regulators of excitation in the nervous system, but their functional diversity is still not well understood. For instance, Kv12.2 (ELK2, KCNH3) channels are highly expressed in the cerebral cortex and hippocampus, and although they are most likely to contribute to resting potassium conductance, surprisingly little is known about their function or regulation. Here we demonstrate that the auxiliary MinK (KCNE1) and MiRP2 (KCNE3) proteins are important regulators of Kv12.2 channel function. Reduction of endogenous KCNE1 or KCNE3 expression by siRNA silencing, significantly increased macroscopic Kv12.2 currents in Xenopus oocytes by around 4-fold. Interestingly, an almost 9-fold increase in Kv12.2 currents was observed with the dual injection of KCNE1 and KCNE3 siRNA, suggesting an additive effect. Consistent with these findings, over-expression of KCNE1 and/or KCNE3 suppressed Kv12.2 currents. Membrane surface biotinylation assays showed that surface expression of Kv12.2 was significantly increased by KCNE1 and KCNE3 siRNA, whereas total protein expression of Kv12.2 was not affected. KCNE1 and KCNE3 siRNA shifted the voltages for half-maximal activation to more hyperpolarized voltages, indicating that KCNE1 and KCNE3 may also inhibit activation gating of Kv12.2. Native co-immunoprecipitation assays from mouse brain membranes imply that KCNE1 and KCNE3 interact with Kv12.2 simultaneously in vivo, suggesting the existence of novel KCNE1-KCNE3-Kv12.2 channel tripartite complexes. Together these data indicate that KCNE1 and KCNE3 interact directly with Kv12.2 channels to regulate channel membrane trafficking.
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Affiliation(s)
- Sinead M. Clancy
- Department of Cell Biology, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California, United States of America
| | - Bihan Chen
- Department of Cell Biology, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California, United States of America
| | - Federica Bertaso
- Department of Cell Biology, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California, United States of America
| | - Julien Mamet
- Department of Cell Biology, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California, United States of America
| | - Timothy Jegla
- Department of Cell Biology, Institute for Childhood and Neglected Diseases, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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Vacher H, Mohapatra DP, Trimmer JS. Localization and targeting of voltage-dependent ion channels in mammalian central neurons. Physiol Rev 2008; 88:1407-47. [PMID: 18923186 DOI: 10.1152/physrev.00002.2008] [Citation(s) in RCA: 348] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The intrinsic electrical properties and the synaptic input-output relationships of neurons are governed by the action of voltage-dependent ion channels. The localization of specific populations of ion channels with distinct functional properties at discrete sites in neurons dramatically impacts excitability and synaptic transmission. Molecular cloning studies have revealed a large family of genes encoding voltage-dependent ion channel principal and auxiliary subunits, most of which are expressed in mammalian central neurons. Much recent effort has focused on determining which of these subunits coassemble into native neuronal channel complexes, and the cellular and subcellular distributions of these complexes, as a crucial step in understanding the contribution of these channels to specific aspects of neuronal function. Here we review progress made on recent studies aimed to determine the cellular and subcellular distribution of specific ion channel subunits in mammalian brain neurons using in situ hybridization and immunohistochemistry. We also discuss the repertoire of ion channel subunits in specific neuronal compartments and implications for neuronal physiology. Finally, we discuss the emerging mechanisms for determining the discrete subcellular distributions observed for many neuronal ion channels.
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Affiliation(s)
- Helene Vacher
- Department of Neurobiology, Physiology, and Behavior, College of Biological Sciences, University of California, Davis, California 95616-8519, USA
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43
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McKee AE, Neretti N, Carvalho LE, Meyer CA, Fox EA, Brodsky AS, Silver PA. Exon expression profiling reveals stimulus-mediated exon use in neural cells. Genome Biol 2008; 8:R159. [PMID: 17683528 PMCID: PMC2374990 DOI: 10.1186/gb-2007-8-8-r159] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 06/12/2007] [Accepted: 08/02/2007] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Neuronal cells respond to changes in intracellular calcium ([Ca2+]i) by affecting both the abundance and architecture of specific mRNAs. Although calcium-induced transcription and transcript variation have both been recognized as important sources of gene regulation, the interplay between these two phenomena has not been evaluated on a genome-wide scale. RESULTS Here, we show that exon-centric microarrays can be used to resolve the [Ca2+]i-modulated gene expression response into transcript-level and exon-level regulation. Global assessments of affected transcripts reveal modulation within distinct functional gene categories. We find that transcripts containing calcium-modulated exons exhibit enrichment for calcium ion binding, calmodulin binding, plasma membrane associated, and metabolic proteins. Additionally, we uncover instances of regulated exon use in potassium channels, neuroendocrine secretory proteins and metabolic enzymes, and demonstrate that regulated changes in exon expression give rise to distinct transcript variants. CONCLUSION Our findings connect extracellular stimuli to specific exon behavior, and suggest that changes in transcript and exon abundance are reflective of a coordinated gene expression response to elevated [Ca2+]i. The technology we describe here lends itself readily to the resolution of stimulus-induced gene expression at both the transcript and exon levels.
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Affiliation(s)
- Adrienne E McKee
- Department of Systems Biology, 200 Longwood Avenue, Harvard Medical School, Boston, Massachusetts 02115, USA.
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Friedland DR, Eernisse R, Popper P. Potassium channel gene expression in the rat cochlear nucleus. Hear Res 2007; 228:31-43. [PMID: 17346910 PMCID: PMC1995076 DOI: 10.1016/j.heares.2007.01.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 01/02/2007] [Accepted: 01/11/2007] [Indexed: 12/15/2022]
Abstract
Potassium channels play a critical role in defining the electrophysiological properties accounting for the unique response patterns of auditory neurons. Serial analysis of gene expression (SAGE), microarrays, RT-PCR, and real-time RT-PCR were used to generate a broad profile of potassium channel expression in the rat cochlear nucleus. This study identified mRNAs for 51 different potassium channel subunits or channel interacting proteins. The relative expression levels of 27 of these transcripts among the AVCN, PVCN, and DCN were determined by real-time RT-PCR. Four potassium channel transcripts showed substantial levels of differential expression. Kcnc2 was expressed more than 15-fold higher in the DCN as compared to AVCN and PVCN. In contrast, Kcnj13 had an approximate 10-fold higher expression in AVCN and PVCN than in DCN. Two subunits that modify the activity of other channels were inversely expressed between ventral and dorsal divisions. Kcns1 was over 15-fold higher in DCN than AVCN or PVCN, while Kcns3 was about 25-fold higher in AVCN than in DCN. The expression patterns of potassium channels in the subdivisions of the cochlear nucleus provide a basis for understanding the electrophysiological mechanisms which sub-serve central auditory processing and provide targets for further investigations into neural plastic changes that occur with hearing loss.
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Affiliation(s)
- David R Friedland
- Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, 9200 W. Wisconsin Ave, Milwaukee, WI, United States.
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