1
|
Wojciechowski MN, McKenzie CE, Hung A, Kuanyshbek A, Soh MS, Reid CA, Forster IC. Different fluorescent labels report distinct components of spHCN channel voltage sensor movement. J Gen Physiol 2024; 156:e202413559. [PMID: 38968404 PMCID: PMC11223168 DOI: 10.1085/jgp.202413559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 05/17/2024] [Accepted: 06/11/2024] [Indexed: 07/07/2024] Open
Abstract
We used voltage clamp fluorometry to probe the movement of the S4 helix in the voltage-sensing domain of the sea urchin HCN channel (spHCN) expressed in Xenopus oocytes. We obtained markedly different fluorescence responses with either ALEXA-488 or MTS-TAMRA covalently linked to N-terminal Cys332 of the S4 helix. With hyperpolarizing steps, ALEXA-488 fluorescence increased rapidly, consistent with it reporting the initial inward movement of S4, as previously described. In contrast, MTS-TAMRA fluorescence increased more slowly and its early phase correlated with that of channel opening. Additionally, a slow fluorescence component that tracked the development of the mode shift, or channel hysteresis, could be resolved with both labels. We quantitated this component as an increased deactivation tail current delay with concomitantly longer activation periods and found it to depend strongly on the presence of K+ ions in the pore. Using collisional quenching experiments and structural predictions, we established that ALEXA-488 was more exposed to solvent than MTS-TAMRA. We propose that components of S4 movement during channel activation can be kinetically resolved using different fluorescent probes to reveal distinct biophysical properties. Our findings underscore the need to apply caution when interpreting voltage clamp fluorometry data and demonstrate the potential utility of different labels to interrogate distinct biophysical properties of voltage-gated membrane proteins.
Collapse
Affiliation(s)
- Magdalena N. Wojciechowski
- Florey Institute of Neuroscience and Mental Health, Parkville, Australia
- Institut für Pharmazeutische und Medizinische Chemie, Pharmacampus, Universität Münster, Münster, Germany
| | | | - Andrew Hung
- School of Science, STEM College, RMIT University, Melbourne, Australia
| | - Alibek Kuanyshbek
- Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | - Ming S. Soh
- Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| | | | - Ian C. Forster
- Florey Institute of Neuroscience and Mental Health, Parkville, Australia
| |
Collapse
|
2
|
Camara MD, Zhou Y, Dara A, Tékété MM, Nóbrega de Sousa T, Sissoko S, Dembélé L, Ouologuem N, Hamidou Togo A, Alhousseini ML, Fofana B, Sagara I, Djimde AA, Gil PJ, Lauschke VM. Population-specific variations in KCNH2 predispose patients to delayed ventricular repolarization upon dihydroartemisinin-piperaquine therapy. Antimicrob Agents Chemother 2024; 68:e0139023. [PMID: 38546223 PMCID: PMC11064487 DOI: 10.1128/aac.01390-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 03/05/2024] [Indexed: 05/03/2024] Open
Abstract
Dihydroartemisinin-piperaquine is efficacious for the treatment of uncomplicated malaria and its use is increasing globally. Despite the positive results in fighting malaria, inhibition of the Kv11.1 channel (hERG; encoded by the KCNH2 gene) by piperaquine has raised concerns about cardiac safety. Whether genetic factors could modulate the risk of piperaquine-mediated QT prolongations remained unclear. Here, we first profiled the genetic landscape of KCNH2 variability using data from 141,614 individuals. Overall, we found 1,007 exonic variants distributed over the entire gene body, 555 of which were missense. By optimizing the gene-specific parametrization of 16 partly orthogonal computational algorithms, we developed a KCNH2-specific ensemble classifier that identified a total of 116 putatively deleterious missense variations. To evaluate the clinical relevance of KCNH2 variability, we then sequenced 293 Malian patients with uncomplicated malaria and identified 13 variations within the voltage sensing and pore domains of Kv11.1 that directly interact with channel blockers. Cross-referencing of genetic and electrocardiographic data before and after piperaquine exposure revealed that carriers of two common variants, rs1805121 and rs41314375, experienced significantly higher QT prolongations (ΔQTc of 41.8 ms and 61 ms, respectively, vs 14.4 ms in controls) with more than 50% of carriers having increases in QTc >30 ms. Furthermore, we identified three carriers of rare population-specific variations who experienced clinically relevant delayed ventricular repolarization. Combined, our results map population-scale genetic variability of KCNH2 and identify genetic biomarkers for piperaquine-induced QT prolongation that could help to flag at-risk patients and optimize efficacy and adherence to antimalarial therapy.
Collapse
Affiliation(s)
- Mahamadou D. Camara
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Yitian Zhou
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Antoine Dara
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Mamadou M. Tékété
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Taís Nóbrega de Sousa
- Department of Microbiology and Tumour Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Molecular Biology and Malaria Immunology Research Group, Instituto René Rachou, Fundação Oswaldo Cruz (FIOCRUZ), Belo Horizonte, Brazil
| | - Sékou Sissoko
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Laurent Dembélé
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Nouhoun Ouologuem
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Amadou Hamidou Togo
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Mohamed L. Alhousseini
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Bakary Fofana
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Issaka Sagara
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Abdoulaye A. Djimde
- Department of Epidemiology of Parasitic Diseases, Malaria Research and Training Center, Faculty of Pharmacy, University of Science, Techniques and Technologies, Bamako, Mali
| | - Pedro J. Gil
- Department of Microbiology and Tumour Cell Biology, Karolinska Institutet, Stockholm, Sweden
- Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Nova University of Lisbon, Lisbon, Portugal
| | - Volker M. Lauschke
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
- University of Tübingen, Tübingen, Germany
| |
Collapse
|
3
|
Roney M, Dubey A, Hassan Nasir M, Tufail A, Tajuddin SN, Mohd Aluwi MFF, Huq AM. Computer-aided anti-cancer drug discovery of EGFR protein based on virtual screening of drug bank, ADMET, docking, DFT and molecular dynamic simulation studies. J Biomol Struct Dyn 2023:1-16. [PMID: 37676262 DOI: 10.1080/07391102.2023.2252092] [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: 01/20/2023] [Accepted: 08/21/2023] [Indexed: 09/08/2023]
Abstract
Numerous malignancies, including breast cancer, non-small cell lung cancer, and chronic myeloid leukemia, are brought on by aberrant tyrosine kinase signaling. Since the current chemotherapeutic medicines are toxic, there is a great need and demand from cancer patients to find novel chemicals that are toxic-free or have low toxicity and that can kill tumor cells and stop their growth. This work describes the in-silico examination of substances from the drug bank as EGFR inhibitors. Firstly, drug-bank was screened using the pharmacophore technique to select the ligands and Erlotinib (DB00530) was used as matrix compound. The selected ligands were screened using ADMET and the hit compounds were subjected to docking. The lead compound from the docking was subjected to DFT and MD simulation study. Using the pharmacophore technique, 23 compounds were found through virtual drug bank screening. One hit molecule from the ADMET prediction was the subject of docking study. According to the findings, DB03365 molecule fits to the EGFR active site by several hydrogen bonding interactions with amino acids. Furthermore, DFT analysis revealed high reactivity for DB03365 compound in the binding pocket of the target protein, based on ELUMO, EHOMO and band energy gap. Furthermore, MD simulations for 100 ns revealed that the ligand interactions with the residues of EGFR protein were part of the essential residues for structural stability and functionality. However, DB03365 was a promising lead molecule that outperformed the reference compound in terms of performance and in-vitro and in-vivo experiments needs to validate the study.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Miah Roney
- Faculty of Industrial Sciences and Technology, Universiti Malafysia Pahang Al-Sultan Abdullah, Lebuhraya Tun Razak, Pahang, Darul Makmur, Malaysia
- Centre for Bio-Aromatic Research, Universiti Malaysia Pahang Al-Sultan Abdullah, Lebuhraya Tun Razak, Pahang, Darul Makmur, Malaysia
| | - Amit Dubey
- Department of Pharmacology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
- Computational Chemistry and Drug Discovery Division, Quanta Calculus, Greater Noida, Uttar Pradesh, India
| | - Muhammad Hassan Nasir
- Faculty of Medicine, University Sultan Zainal Abidin (UniSZA), Terengganu, Darul Iman, Malaysia
| | - Aisha Tufail
- Department of Pharmacology, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India
| | - Saiful Nizam Tajuddin
- Centre for Bio-Aromatic Research, Universiti Malaysia Pahang Al-Sultan Abdullah, Lebuhraya Tun Razak, Pahang, Darul Makmur, Malaysia
| | - Mohd Fadhlizil Fasihi Mohd Aluwi
- Faculty of Industrial Sciences and Technology, Universiti Malafysia Pahang Al-Sultan Abdullah, Lebuhraya Tun Razak, Pahang, Darul Makmur, Malaysia
- Centre for Bio-Aromatic Research, Universiti Malaysia Pahang Al-Sultan Abdullah, Lebuhraya Tun Razak, Pahang, Darul Makmur, Malaysia
| | - Akm Moyeenul Huq
- Centre for Bio-Aromatic Research, Universiti Malaysia Pahang Al-Sultan Abdullah, Lebuhraya Tun Razak, Pahang, Darul Makmur, Malaysia
- Department of Pharmacy, School of Medicine, University of Asia Pacific 74/A, Dhaka, Bangladesh
| |
Collapse
|
4
|
Bogard A, Finn PW, Smith AR, Flacau IM, Whiting R, Fologea D. Modulation of Voltage-Gating and Hysteresis of Lysenin Channels by Cu 2+ Ions. Int J Mol Sci 2023; 24:12996. [PMID: 37629177 PMCID: PMC10455686 DOI: 10.3390/ijms241612996] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 08/12/2023] [Accepted: 08/18/2023] [Indexed: 08/27/2023] Open
Abstract
The intricate voltage regulation presented by lysenin channels reconstituted in artificial lipid membranes leads to a strong hysteresis in conductance, bistability, and memory. Prior investigations on lysenin channels indicate that the hysteresis is modulated by multivalent cations which are also capable of eliciting single-step conformational changes and transitions to stable closed or sub-conducting states. However, the influence on voltage regulation of Cu2+ ions, capable of completely closing the lysenin channels in a two-step process, was not sufficiently addressed. In this respect, we employed electrophysiology approaches to investigate the response of lysenin channels to variable voltage stimuli in the presence of small concentrations of Cu2+ ions. Our experimental results showed that the hysteretic behavior, recorded in response to variable voltage ramps, is accentuated in the presence of Cu2+ ions. Using simultaneous AC/DC stimulation, we were able to determine that Cu2+ prevents the reopening of channels previously closed by depolarizing potentials and the channels remain in the closed state even in the absence of a transmembrane voltage. In addition, we showed that Cu2+ addition reinstates the voltage gating and hysteretic behavior of lysenin channels reconstituted in neutral lipid membranes in which lysenin channels lose their voltage-regulating properties. In the presence of Cu2+ ions, lysenin not only regained the voltage gating but also behaved like a long-term molecular memory controlled by electrical potentials.
Collapse
Affiliation(s)
- Andrew Bogard
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, State University, Boise, ID 83725, USA
| | - Pangaea W. Finn
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Aviana R. Smith
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Ilinca M. Flacau
- Department of Physics, Boise State University, Boise, ID 83725, USA
| | - Rose Whiting
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, State University, Boise, ID 83725, USA
| | - Daniel Fologea
- Department of Physics, Boise State University, Boise, ID 83725, USA
- Biomolecular Sciences Graduate Program, State University, Boise, ID 83725, USA
| |
Collapse
|
5
|
AlRawashdeh S, Chandrasekaran S, Barakat KH. Structural analysis of hERG channel blockers and the implications for drug design. J Mol Graph Model 2023; 120:108405. [PMID: 36680816 DOI: 10.1016/j.jmgm.2023.108405] [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: 10/12/2022] [Revised: 12/26/2022] [Accepted: 01/09/2023] [Indexed: 01/13/2023]
Abstract
The repolarizing current (Ikr) produced by the hERG potassium channel forms a major component of the cardiac action potential and blocking this current by small molecule drugs can lead to life-threatening cardiotoxicity. Understanding the mechanisms of drug-mediated hERG inhibition is essential to develop a second generation of safe drugs, with minimal cardiotoxic effects. Although various computational tools and drug design guidelines have been developed to avoid binding of drugs to the hERG pore domain, there are many other aspects that are still open for investigation. This includes the use computational modelling to study the implications of hERG mutations on hERG structure and trafficking, the interactions of hERG with hERG chaperone proteins and with membrane-soluble molecules, the mechanisms of drugs that inhibit hERG trafficking and drugs that rescue hERG mutations. The plethora of available experimental data regarding all these aspects can guide the construction of much needed robust computational structural models to study these mechanisms for the rational design of safe drugs.
Collapse
Affiliation(s)
- Sara AlRawashdeh
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada
| | | | - Khaled H Barakat
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada.
| |
Collapse
|
6
|
Giannotta G, Murrone A, Giannotta N. COVID-19 mRNA Vaccines: The Molecular Basis of Some Adverse Events. Vaccines (Basel) 2023; 11:vaccines11040747. [PMID: 37112659 PMCID: PMC10145134 DOI: 10.3390/vaccines11040747] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 03/21/2023] [Accepted: 03/22/2023] [Indexed: 03/30/2023] Open
Abstract
Each injection of any known vaccine results in a strong expression of pro-inflammatory cytokines. This is the result of the innate immune system activation, without which no adaptive response to the injection of vaccines is possible. Unfortunately, the degree of inflammation produced by COVID-19 mRNA vaccines is variable, probably depending on genetic background and previous immune experiences, which through epigenetic modifications could have made the innate immune system of each individual tolerant or reactive to subsequent immune stimulations.We hypothesize that we can move from a limited pro-inflammatory condition to conditions of increasing expression of pro-inflammatory cytokines that can culminate in multisystem hyperinflammatory syndromes following COVID-19 mRNA vaccines (MIS-V). We have graphically represented this idea in a hypothetical inflammatory pyramid (IP) and we have correlated the time factor to the degree of inflammation produced after the injection of vaccines. Furthermore, we have placed the clinical manifestations within this hypothetical IP, correlating them to the degree of inflammation produced. Surprisingly, excluding the possible presence of an early MIS-V, the time factor and the complexity of clinical manifestations are correlated to the increasing degree of inflammation: symptoms, heart disease and syndromes (MIS-V).
Collapse
|
7
|
Cowgill J, Chanda B. Charge-voltage curves of Shaker potassium channel are not hysteretic at steady state. J Gen Physiol 2023; 155:213823. [PMID: 36692860 PMCID: PMC9884579 DOI: 10.1085/jgp.202112883] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 02/16/2022] [Accepted: 01/03/2023] [Indexed: 01/25/2023] Open
Abstract
Charge-voltage curves of many voltage-gated ion channels exhibit hysteresis but such curves are also a direct measure of free energy of channel gating and, hence, should be path-independent. Here, we identify conditions to measure steady-state charge-voltage curves and show that these are curves are not hysteretic. Charged residues in transmembrane segments of voltage-gated ion channels (VGICs) sense and respond to changes in the electric field. The movement of these gating charges underpins voltage-dependent activation and is also a direct metric of the net free-energy of channel activation. However, for most voltage-gated ion channels, the charge-voltage (Q-V) curves appear to be dependent on initial conditions. For instance, Q-V curves of Shaker potassium channel obtained by hyperpolarizing from 0 mV is left-shifted compared to those obtained by depolarizing from a holding potential of -80 mV. This hysteresis in Q-V curves is a common feature of channels in the VGIC superfamily and raises profound questions about channel energetics because the net free-energy of channel gating is a state function and should be path independent. Due to technical limitations, conventional gating current protocols are limited to test pulse durations of <500 ms, which raises the possibility that the dependence of Q-V on initial conditions reflects a lack of equilibration. Others have suggested that the hysteresis is fundamental thermodynamic property of voltage-gated ion channels and reflects energy dissipation due to measurements under non-equilibrium conditions inherent to rapid voltage jumps (Villalba-Galea. 2017. Channels. https://doi.org/10.1080/19336950.2016.1243190). Using an improved gating current and voltage-clamp fluorometry protocols, we show that the gating hysteresis arising from different initial conditions in Shaker potassium channel is eliminated with ultra-long (18-25 s) test pulses. Our study identifies a modified gating current recording protocol to obtain steady-state Q-V curves of a voltage-gated ion channel. Above all, these findings demonstrate that the gating hysteresis in Shaker channel is a kinetic phenomenon rather than a true thermodynamic property of the channel and the charge-voltage curve is a true measure of the net-free energy of channel gating.
Collapse
Affiliation(s)
- John Cowgill
- Departments of Anesthesiology, Neuroscience, Biochemistry and Molecular Biophysics, Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, USA,John Cowgill:
| | - Baron Chanda
- Departments of Anesthesiology, Neuroscience, Biochemistry and Molecular Biophysics, Center for Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO, USA,Correspondence to Baron Chanda:
| |
Collapse
|
8
|
Veldhuizen J, Mann HF, Karamanova N, Van Horn WD, Migrino RQ, Brafman D, Nikkhah M. Modeling long QT syndrome type 2 on-a-chip via in-depth assessment of isogenic gene-edited 3D cardiac tissues. SCIENCE ADVANCES 2022; 8:eabq6720. [PMID: 36525500 PMCID: PMC9757749 DOI: 10.1126/sciadv.abq6720] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 11/16/2022] [Indexed: 06/09/2023]
Abstract
Long QT syndrome (LQTS) is a cardiovascular disease characterized by QT interval prolongation that can lead to sudden cardiac death. Many mutations with heterogeneous mechanisms have been identified in KCNH2, the gene that encodes for hERG (Kv11.1), which lead to onset of LQTS type 2 (LQTS2). In this work, we developed a LQTS2-diseased tissue-on-a-chip model, using 3D coculture of isogenic stem cell-derived cardiomyocytes (CMs) and cardiac fibroblasts (CFs) within an organotypic microfluidic chip technology. Primarily, we created a hiPSC line with R531W mutation in KCNH2 using CRISPR-Cas9 gene-editing technique and characterized the resultant differentiated CMs and CFs. A deficiency in hERG trafficking was identified in KCNH2-edited hiPSC-CMs, revealing a possible mechanism of R531W mutation in LQTS2 pathophysiology. Following creation of a 3D LQTS2 tissue-on-a-chip, the tissues were extensively characterized, through analysis of calcium handling and response to β-agonist. Furthermore, attempted phenotypic rescue via pharmacological intervention of LQTS2 on a chip was investigated.
Collapse
Affiliation(s)
- Jaimeson Veldhuizen
- School of Biological and Health Systems Engineering (SBHSE), Arizona State University, Tempe, AZ 85287, USA
| | - Helen F. Mann
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Nina Karamanova
- Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
| | - Wade D. Van Horn
- School of Molecular Sciences, Arizona State University, Tempe, AZ 85287, USA
- Biodesign Center for Personalized Diagnostics, Arizona State University, Tempe, AZ 85287, USA
| | - Raymond Q. Migrino
- Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
- University of Arizona College of Medicine, Phoenix, AZ 85004, USA
| | - David Brafman
- School of Biological and Health Systems Engineering (SBHSE), Arizona State University, Tempe, AZ 85287, USA
| | - Mehdi Nikkhah
- School of Biological and Health Systems Engineering (SBHSE), Arizona State University, Tempe, AZ 85287, USA
- Biodesign Center for Personalized Diagnostics, Arizona State University, Tempe, AZ 85287, USA
| |
Collapse
|
9
|
Wu SN, Wu CL, Cho HY, Chiang CW. Effective Perturbations by Small-Molecule Modulators on Voltage-Dependent Hysteresis of Transmembrane Ionic Currents. Int J Mol Sci 2022; 23:ijms23169453. [PMID: 36012718 PMCID: PMC9408818 DOI: 10.3390/ijms23169453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
The non-linear voltage-dependent hysteresis (Hys(V)) of voltage-gated ionic currents can be robustly activated by the isosceles-triangular ramp voltage (Vramp) through digital-to-analog conversion. Perturbations on this Hys(V) behavior play a role in regulating membrane excitability in different excitable cells. A variety of small molecules may influence the strength of Hys(V) in different types of ionic currents elicited by long-lasting triangular Vramp. Pirfenidone, an anti-fibrotic drug, decreased the magnitude of Ih's Hys(V) activated by triangular Vramp, while dexmedetomidine, an agonist of α2-adrenoceptors, effectively suppressed Ih as well as diminished the Hys(V) strength of Ih. Oxaliplatin, a platinum-based anti-neoplastic drug, was noted to enhance the Ih's Hys(V) strength, which is thought to be linked to the occurrence of neuropathic pain, while honokiol, a hydroxylated biphenyl compound, decreased Ih's Hys(V). Cell exposure to lutein, a xanthophyll carotenoid, resulted in a reduction of Ih's Hys(V) magnitude. Moreover, with cell exposure to UCL-2077, SM-102, isoplumbagin, or plumbagin, the Hys(V) strength of erg-mediated K+ current activated by triangular Vramp was effectively diminished, whereas the presence of either remdesivir or QO-58 respectively decreased or increased Hys(V) magnitude of M-type K+ current. Zingerone, a methoxyphenol, was found to attenuate Hys(V) (with low- and high-threshold loops) of L-type Ca2+ current induced by long-lasting triangular Vramp. The Hys(V) properties of persistent Na+ current (INa(P)) evoked by triangular Vramp were characterized by a figure-of-eight (i.e., ∞) configuration with two distinct loops (i.e., low- and high-threshold loops). The presence of either tefluthrin, a pyrethroid insecticide, or t-butyl hydroperoxide, an oxidant, enhanced the Hys(V) strength of INa(P). However, further addition of dapagliflozin can reverse their augmenting effects in the Hys(V) magnitude of the current. Furthermore, the addition of esaxerenone, mirogabalin, or dapagliflozin was effective in inhibiting the strength of INa(P). Taken together, the observed perturbations by these small-molecule modulators on Hys(V) strength in different types of ionic currents evoked during triangular Vramp are expected to influence the functional activities (e.g., electrical behaviors) of different excitable cells in vitro or in vivo.
Collapse
Affiliation(s)
- Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 70101, Taiwan
- Department of Post-Baccalaureate Medicine, National Sun Yat-sen University, Kaohsiung 804201, Taiwan
- Correspondence: ; Tel.: +886-6-2353535 (ext. 5334); Fax: +886-6-2362780
| | - Chao-Liang Wu
- Department of Medical Research, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Hsin-Yen Cho
- Department of Physiology, National Cheng Kung University Medical College, Tainan 70101, Taiwan
| | - Chi-Wu Chiang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan 70101, Taiwan
| |
Collapse
|
10
|
Sanchez-Conde FG, Jimenez-Vazquez EN, Auerbach DS, Jones DK. The ERG1 K+ Channel and Its Role in Neuronal Health and Disease. Front Mol Neurosci 2022; 15:890368. [PMID: 35600076 PMCID: PMC9113952 DOI: 10.3389/fnmol.2022.890368] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 04/11/2022] [Indexed: 11/30/2022] Open
Abstract
The ERG1 potassium channel, encoded by KCNH2, has long been associated with cardiac electrical excitability. Yet, a growing body of work suggests that ERG1 mediates physiology throughout the human body, including the brain. ERG1 is a regulator of neuronal excitability, ERG1 variants are associated with neuronal diseases (e.g., epilepsy and schizophrenia), and ERG1 serves as a potential therapeutic target for neuronal pathophysiology. This review summarizes the current state-of-the-field regarding the ERG1 channel structure and function, ERG1’s relationship to the mammalian brain and highlights key questions that have yet to be answered.
Collapse
Affiliation(s)
| | - Eric N. Jimenez-Vazquez
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - David S. Auerbach
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, NY, United States
- *Correspondence: David S. Auerbach,
| | - David K. Jones
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
- David K. Jones,
| |
Collapse
|
11
|
Panagopoulos DJ, Karabarbounis A, Yakymenko I, Chrousos GP. Human‑made electromagnetic fields: Ion forced‑oscillation and voltage‑gated ion channel dysfunction, oxidative stress and DNA damage (Review). Int J Oncol 2021; 59:92. [PMID: 34617575 PMCID: PMC8562392 DOI: 10.3892/ijo.2021.5272] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 08/23/2021] [Indexed: 12/13/2022] Open
Abstract
Exposure of animals/biological samples to human‑made electromagnetic fields (EMFs), especially in the extremely low frequency (ELF) band, and the microwave/radio frequency (RF) band which is always combined with ELF, may lead to DNA damage. DNA damage is connected with cell death, infertility and other pathologies, including cancer. ELF exposure from high‑voltage power lines and complex RF exposure from wireless communication antennas/devices are linked to increased cancer risk. Almost all human‑made RF EMFs include ELF components in the form of modulation, pulsing and random variability. Thus, in addition to polarization and coherence, the existence of ELFs is a common feature of almost all human‑made EMFs. The present study reviews the DNA damage and related effects induced by human‑made EMFs. The ion forced‑oscillation mechanism for irregular gating of voltage‑gated ion channels on cell membranes by polarized/coherent EMFs is extensively described. Dysfunction of ion channels disrupts intracellular ionic concentrations, which determine the cell's electrochemical balance and homeostasis. The present study shows how this can result in DNA damage through reactive oxygen species/free radical overproduction. Thus, a complete picture is provided of how human‑made EMF exposure may indeed lead to DNA damage and related pathologies, including cancer. Moreover, it is suggested that the non‑thermal biological effects attributed to RF EMFs are actually due to their ELF components.
Collapse
Affiliation(s)
- Dimitris J. Panagopoulos
- Laboratory of Health Physics, Radiobiology and Cytogenetics, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Center for Scientific Research 'Demokritos', 15310 Athens, Greece
- Choremeion Research Laboratory, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
- Electromagnetic Field-Biophysics Research Laboratory, 10681 Athens, Greece
| | - Andreas Karabarbounis
- Department of Physics, Section of Nuclear and Particle Physics, National and Kapodistrian University of Athens, 15784 Athens, Greece
| | - Igor Yakymenko
- Institute of Experimental Pathology, Oncology and Radiobiology of National Academy of Science of Ukraine, 03022 Kyiv, Ukraine
- Department of Public Health, Kyiv Medical University, 02000 Kyiv, Ukraine
| | - George P. Chrousos
- Choremeion Research Laboratory, Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Zequn Z, Jiangfang L. Molecular Insights Into the Gating Kinetics of the Cardiac hERG Channel, Illuminated by Structure and Molecular Dynamics. Front Pharmacol 2021; 12:687007. [PMID: 34168566 PMCID: PMC8217747 DOI: 10.3389/fphar.2021.687007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 05/20/2021] [Indexed: 11/13/2022] Open
Abstract
The rapidly activating delayed rectifier K+ current generated by the cardiac hERG potassium channel encoded by KCNH2 is the most important reserve current for cardiac repolarization. The unique inward rectification characteristics of the hERG channel depend on the gating regulation, which involves crucial structural domains and key single amino acid residues in the full-length hERG channel. Identifying critical molecules involved in the regulation of gating kinetics for the hERG channel requires high-resolution structures and molecular dynamics simulation models. Based on the latest progress in hERG structure and molecular dynamics simulation research, summarizing the molecules involved in the changes in the channel state helps to elucidate the unique gating characteristics of the channel and the reason for its high affinity to cardiotoxic drugs. In this review, we aim to summarize the significant advances in understanding the voltage gating regulation of the hERG channel based on its structure obtained from cryo-electron microscopy and computer simulations, which reveal the critical roles of several specific structural domains and amino acid residues.
Collapse
Affiliation(s)
- Zheng Zequn
- Department of Cardiovascular, Medical College, Ningbo University, Ningbo, China
| | - Lian Jiangfang
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo, China
| |
Collapse
|
14
|
Zequn Z, Yujia W, Dingding Q, Jiangfang L. Off-label use of chloroquine, hydroxychloroquine, azithromycin and lopinavir/ritonavir in COVID-19 risks prolonging the QT interval by targeting the hERG channel. Eur J Pharmacol 2020; 893:173813. [PMID: 33345848 PMCID: PMC7746509 DOI: 10.1016/j.ejphar.2020.173813] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 11/29/2020] [Accepted: 12/11/2020] [Indexed: 12/20/2022]
Abstract
Coronavirus disease-2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), poses an enormous challenge to the medical system, especially the lack of safe and effective COVID-19 treatment methods, forcing people to look for drugs that may have therapeutic effects as soon as possible. Some old drugs have shown clinical benefits after a few small clinical trials that attracted great attention. Clinically, however, many drugs, including those currently used in COVID-19, such as chloroquine, hydroxychloroquine, azithromycin, and lopinavir/ritonavir, may cause cardiotoxicity by acting on cardiac potassium channels, especially hERG channel through their off-target effects. The blocking of the hERG channel prolongs QT intervals on electrocardiograms; thus, it might induce severe ventricular arrhythmias and even sudden cardiac death. Therefore, while focusing on the efficacy of COVID-19 drugs, the fact that they block hERG channels to cause arrhythmias cannot be ignored. To develop safer and more effective drugs, it is necessary to understand the interactions between drugs and the hERG channel and the molecular mechanism behind this high affinity. In this review, we focus on the biochemical and molecular mechanistic aspects of drug-related blockade of the hERG channel to provide insights into QT prolongation caused by off-label use of related drugs in COVID-19, and hope to weigh the risks and benefits when using these drugs.
Collapse
Affiliation(s)
- Zheng Zequn
- Medical College, Ningbo University, Ningbo, Zhejiang, 315000, China
| | - Wu Yujia
- Medical College, Ningbo University, Ningbo, Zhejiang, 315000, China
| | - Qian Dingding
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo, Zhejiang, 315211, China
| | - Lian Jiangfang
- Department of Cardiovascular, Lihuili Hospital Affiliated to Ningbo University, Ningbo, Zhejiang, 315211, China.
| |
Collapse
|
15
|
Villalba-Galea CA, Chiem AT. Hysteretic Behavior in Voltage-Gated Channels. Front Pharmacol 2020; 11:579596. [PMID: 33324211 PMCID: PMC7723447 DOI: 10.3389/fphar.2020.579596] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/21/2020] [Indexed: 01/22/2023] Open
Abstract
An ever-growing body of evidence has shown that voltage-gated ion channels are likely molecular systems that display hysteresis in their activity. This phenomenon manifests in the form of dynamic changes in both their voltage dependence of activity and their deactivation kinetics. The goal of this review is to provide a clear definition of hysteresis in terms of the behavior of voltage-gated channels. This review will discuss the basic behavior of voltage-gated channel activity and how they make these proteins into systems displaying hysteresis. It will also provide a perspective on putative mechanisms underlying hysteresis and explain its potential physiological relevance. It is uncertain whether all channels display hysteresis in their behavior. However, the suggested notion that ion channels are hysteretic systems directly collides with the well-accepted notion that ion channel activity is stochastic. This is because hysteretic systems are regarded to have “memory” of previous events while stochastic processes are regarded as “memoryless.” This review will address this apparent contradiction, providing arguments for the existence of processes that can be simultaneously hysteretic and stochastic.
Collapse
Affiliation(s)
- Carlos A Villalba-Galea
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| | - Alvin T Chiem
- Department of Physiology and Pharmacology, Thomas J. Long School of Pharmacy, University of the Pacific, Stockton, CA, United States
| |
Collapse
|
16
|
Liu PY, Chang WT, Wu SN. Characterization of the Synergistic Inhibition of IK(erg) and IK(DR) by Ribociclib, a Cyclin-Dependent Kinase 4/6 Inhibitor. Int J Mol Sci 2020; 21:ijms21218078. [PMID: 33138174 PMCID: PMC7663338 DOI: 10.3390/ijms21218078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/21/2020] [Accepted: 10/28/2020] [Indexed: 12/13/2022] Open
Abstract
Ribociclib (RIB, LE011, Kisqali®), an orally administered inhibitor of cyclin-dependent kinase-4/6 (CDK-4/6) complex, is clinically effective for the treatment of several malignancies, including advanced breast cancer. However, information regarding the effects of RIB on membrane ion currents is limited. In this study, the addition of RIB to pituitary tumor (GH3) cells decreased the peak amplitude of erg-mediated K+ current (IK(erg)), which was accompanied by a slowed deactivation rate of the current. The IC50 value for RIB-perturbed inhibition of deactivating IK(erg) in these cells was 2.7 μM. In continued presence of μM RIB, neither the subsequent addition of 17β-estradiol (30 μM), phorbol 12-myristate 13-acetate (10 μM), or transforming growth factor-β (1 μM) counteracted the inhibition of deactivating IK(erg). Its presence affected the decrease in the degree of voltage-dependent hysteresis for IK(erg) elicitation by long-duration triangular ramp voltage commands. The presence of RIB differentially inhibited the peak or sustained component of delayed rectifier K+ current (IK(DR)) with an effective IC50 of 28.7 or 11.4 μM, respectively, while it concentration-dependently decreased the amplitude of M-type K+ current with IC50 of 13.3 μM. Upon 10-s long membrane depolarization, RIB elicited a decrease in the IK(DR) amplitude, which was concomitant with an accelerated inactivation time course. However, the inability of RIB (10 μM) to modify the magnitude of the hyperpolarization-activated cation current was disclosed. The mean current–voltage relationship of IK(erg) present in HL-1 atrial cardiomyocytes was inhibited in the presence of RIB (10 μM). Collectively, the hyperpolarization-activated cation current was observed. RIB-mediated perturbations in ionic currents presented herein are upstream of its suppressive action on cytosolic CDK-4/6 activities and partly participates in its modulatory effects on the functional activities of pituitary tumor cells (e.g., GH3 cells) or cardiac myocytes (e.g., HL-1 cells).
Collapse
Affiliation(s)
- Pin-Yen Liu
- Division of Cardiovascular Medicine, Department of Internal Medicine, College of Medicine, National Cheng Kung University Hospital, Tainan 704, Taiwan;
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan;
| | - Wei-Ting Chang
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan 704, Taiwan;
- Division of Cardiovascular Medicine, Chi-Mei Medical Center, Tainan 710, Taiwan
- Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan 71005, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology, National Cheng Kung University Medical College, Tainan 704, Taiwan
- Institute of Basic Medical Sciences, National Cheng Kung University Medical College, Tainan 704, Taiwan
- Correspondence: ; Tel.: +886-6-2353535-5334; Fax: +886-6-2362780
| |
Collapse
|