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Abstract
The CACNA1C gene encodes the pore-forming subunit of the CaV1.2 L-type Ca2+ channel, a critical component of membrane physiology in multiple tissues, including the heart, brain, and immune system. As such, mutations altering the function of these channels have the potential to impact a wide array of cellular functions. The first mutations identified within CACNA1C were shown to cause a severe, multisystem disorder known as Timothy syndrome (TS), which is characterized by neurodevelopmental deficits, long-QT syndrome, life-threatening cardiac arrhythmias, craniofacial abnormalities, and immune deficits. Since this initial description, the number and variety of disease-associated mutations identified in CACNA1C have grown tremendously, expanding the range of phenotypes observed in affected patients. CACNA1C channelopathies are now known to encompass multisystem phenotypes as described in TS, as well as more selective phenotypes where patients may exhibit predominantly cardiac or neurological symptoms. Here, we review the impact of genetic mutations on CaV1.2 function and the resultant physiological consequences.
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Affiliation(s)
- Kevin G Herold
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - John W Hussey
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Ivy E Dick
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA.
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2
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Bamgboye MA, Traficante MK, Owoyemi J, DiSilvestre D, Vieira DCO, Dick IE. Impaired Ca V1.2 inactivation reduces the efficacy of calcium channel blockers in the treatment of LQT8. J Mol Cell Cardiol 2022; 173:92-100. [PMID: 36272554 PMCID: PMC10583761 DOI: 10.1016/j.yjmcc.2022.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 10/12/2022] [Accepted: 10/16/2022] [Indexed: 11/23/2022]
Abstract
Mutations in the CaV1.2 L-type calcium channel can cause a profound form of long-QT syndrome known as long-QT type 8 (LQT8), which results in cardiac arrhythmias that are often fatal in early childhood. A growing number of such pathogenic mutations in CaV1.2 have been identified, increasing the need for targeted therapies. As many of these mutations reduce channel inactivation; resulting in excess Ca2+ entry during the action potential, calcium channel blockers (CCBs) would seem to represent a promising treatment option. Yet CCBs have been unsuccessful in the treatment of LQT8. Here, we demonstrate that this lack of efficacy likely stems from the impact of the mutations on CaV1.2 channel inactivation. As CCBs are known to preferentially bind to the inactivated state of the channel, mutation-dependent deficits in inactivation result in a decrease in use-dependent block of the mutant channel. Further, application of the CCB verapamil to induced pluripotent stem cell (iPSC) derived cardiomyocytes from an LQT8 patient demonstrates that this loss of use-dependent block translates to a lack of efficacy in correcting the LQT phenotype. As a growing number of channelopathic mutations demonstrate effects on channel inactivation, reliance on state-dependent blockers may leave a growing population of patients without a viable treatment option. This biophysical understanding of the interplay between inactivation deficits and state-dependent block may provide a new avenue to guide the development of improved therapies.
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Affiliation(s)
- Moradeke A Bamgboye
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Maria K Traficante
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Josiah Owoyemi
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Deborah DiSilvestre
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Daiana C O Vieira
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America
| | - Ivy E Dick
- Department of Physiology, University of Maryland, School of Medicine, Baltimore, MD, United States of America.
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3
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Experimental factors that impact CaV1.2 channel pharmacology-Effects of recording temperature, charge carrier, and quantification of drug effects on the step and ramp currents elicited by the "step-step-ramp" voltage protocol. PLoS One 2022; 17:e0276995. [PMID: 36417390 PMCID: PMC9683570 DOI: 10.1371/journal.pone.0276995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 10/18/2022] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE CaV1.2 channels contribute to action potential upstroke in pacemaker cells, plateau potential in working myocytes, and initiate excitation-contraction coupling. Understanding drug action on CaV1.2 channels may inform potential impact on cardiac function. However, literature shows large degrees of variability between CaV1.2 pharmacology generated by different laboratories, casting doubt regarding the utility of these data to predict or interpret clinical outcomes. This study examined experimental factors that may impact CaV1.2 pharmacology. EXPERIMENTAL APPROACH Whole cell recordings were made on CaV1.2 overexpression cells. Current was evoked using a "step-step-ramp" waveform that elicited a step and a ramp current. Experimental factors examined were: 1) near physiological vs. room temperature for recording, 2) drug inhibition of the step vs. the ramp current, and 3) Ca2+ vs. Ba2+ as the charge carrier. Eight drugs were studied. KEY RESULTS CaV1.2 current exhibited prominent rundown, exquisite temperature sensitivity, and required a high degree of series resistance compensation to optimize voltage control. Temperature-dependent effects were examined for verapamil and methadone. Verapamil's block potency shifted by up to 4X between room to near physiological temperature. Methadone exhibited facilitatory and inhibitory effects at near physiological temperature, and only inhibitory effect at room temperature. Most drugs inhibited the ramp current more potently than the step current-a preference enhanced when Ba2+ was the charge carrier. The slopes of the concentration-inhibition relationships for many drugs were shallow, temperature-dependent, and differed between the step and the ramp current. CONCLUSIONS AND IMPLICATIONS All experimental factors examined affected CaV1.2 pharmacology. In addition, whole cell CaV1.2 current characteristics-rundown, temperature sensitivity, and impact of series resistance-are also factors that can impact pharmacology. Drug effects on CaV1.2 channels appear more complex than simple pore block mechanism. Normalizing laboratory-specific approaches is key to improve inter-laboratory data reproducibility. Releasing original electrophysiology records is essential to promote transparency and enable the independent evaluation of data quality.
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Lanzetti S, Di Biase V. Small Molecules as Modulators of Voltage-Gated Calcium Channels in Neurological Disorders: State of the Art and Perspectives. Molecules 2022; 27:1312. [PMID: 35209100 PMCID: PMC8879281 DOI: 10.3390/molecules27041312] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 01/03/2023] Open
Abstract
Voltage-gated calcium channels (VGCCs) are widely expressed in the brain, heart and vessels, smooth and skeletal muscle, as well as in endocrine cells. VGCCs mediate gene transcription, synaptic and neuronal structural plasticity, muscle contraction, the release of hormones and neurotransmitters, and membrane excitability. Therefore, it is not surprising that VGCC dysfunction results in severe pathologies, such as cardiovascular conditions, neurological and psychiatric disorders, altered glycemic levels, and abnormal smooth muscle tone. The latest research findings and clinical evidence increasingly show the critical role played by VGCCs in autism spectrum disorders, Parkinson's disease, drug addiction, pain, and epilepsy. These findings outline the importance of developing selective calcium channel inhibitors and modulators to treat such prevailing conditions of the central nervous system. Several small molecules inhibiting calcium channels are currently used in clinical practice to successfully treat pain and cardiovascular conditions. However, the limited palette of molecules available and the emerging extent of VGCC pathophysiology require the development of additional drugs targeting these channels. Here, we provide an overview of the role of calcium channels in neurological disorders and discuss possible strategies to generate novel therapeutics.
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Affiliation(s)
| | - Valentina Di Biase
- Institute of Pharmacology, Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, Peter-Mayr Strasse 1, A-6020 Innsbruck, Austria;
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Using induced pluripotent stem cells to investigate human neuronal phenotypes in 1q21.1 deletion and duplication syndrome. Mol Psychiatry 2022; 27:819-830. [PMID: 34112971 PMCID: PMC9054650 DOI: 10.1038/s41380-021-01182-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/17/2021] [Accepted: 05/27/2021] [Indexed: 01/08/2023]
Abstract
Copy Number Variation (CNV) at the 1q21.1 locus is associated with a range of neurodevelopmental and psychiatric disorders in humans, including abnormalities in head size and motor deficits. Yet, the functional consequences of these CNVs (both deletion and duplication) on neuronal development remain unknown. To determine the impact of CNV at the 1q21.1 locus on neuronal development, we generated induced pluripotent stem cells from individuals harbouring 1q21.1 deletion or duplication and differentiated them into functional cortical neurons. We show that neurons with 1q21.1 deletion or duplication display reciprocal phenotype with respect to proliferation, differentiation potential, neuronal maturation, synaptic density and functional activity. Deletion of the 1q21.1 locus was also associated with an increased expression of lower cortical layer markers. This difference was conserved in the mouse model of 1q21.1 deletion, which displayed altered corticogenesis. Importantly, we show that neurons with 1q21.1 deletion and duplication are associated with differential expression of calcium channels and demonstrate that physiological deficits in neurons with 1q21.1 deletion or duplication can be pharmacologically modulated by targeting Ca2+ channel activity. These findings provide biological insight into the neuropathological mechanism underlying 1q21.1 associated brain disorder and indicate a potential target for therapeutic interventions.
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Angelini M, Pezhouman A, Savalli N, Chang MG, Steccanella F, Scranton K, Calmettes G, Ottolia M, Pantazis A, Karagueuzian HS, Weiss JN, Olcese R. Suppression of ventricular arrhythmias by targeting late L-type Ca2+ current. J Gen Physiol 2021; 153:212725. [PMID: 34698805 PMCID: PMC8552156 DOI: 10.1085/jgp.202012584] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 07/15/2021] [Accepted: 09/02/2021] [Indexed: 12/15/2022] Open
Abstract
Ventricular arrhythmias, a leading cause of sudden cardiac death, can be triggered by cardiomyocyte early afterdepolarizations (EADs). EADs can result from an abnormal late activation of L-type Ca2+ channels (LTCCs). Current LTCC blockers (class IV antiarrhythmics), while effective at suppressing EADs, block both early and late components of ICa,L, compromising inotropy. However, computational studies have recently demonstrated that selective reduction of late ICa,L (Ca2+ influx during late phases of the action potential) is sufficient to potently suppress EADs, suggesting that effective antiarrhythmic action can be achieved without blocking the early peak ICa,L, which is essential for proper excitation–contraction coupling. We tested this new strategy using a purine analogue, roscovitine, which reduces late ICa,L with minimal effect on peak current. Scaling our investigation from a human CaV1.2 channel clone to rabbit ventricular myocytes and rat and rabbit perfused hearts, we demonstrate that (1) roscovitine selectively reduces ICa,L noninactivating component in a human CaV1.2 channel clone and in ventricular myocytes native current, (2) the pharmacological reduction of late ICa,L suppresses EADs and EATs (early after Ca2+ transients) induced by oxidative stress and hypokalemia in isolated myocytes, largely preserving cell shortening and normal Ca2+ transient, and (3) late ICa,L reduction prevents/suppresses ventricular tachycardia/fibrillation in ex vivo rabbit and rat hearts subjected to hypokalemia and/or oxidative stress. These results support the value of an antiarrhythmic strategy based on the selective reduction of late ICa,L to suppress EAD-mediated arrhythmias. Antiarrhythmic therapies based on this idea would modify the gating properties of CaV1.2 channels rather than blocking their pore, largely preserving contractility.
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Affiliation(s)
- Marina Angelini
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Arash Pezhouman
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Nicoletta Savalli
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Marvin G Chang
- Department of Anesthesia and Critical Care, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Federica Steccanella
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Kyle Scranton
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Guillaume Calmettes
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Michela Ottolia
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,University of California, Los Angeles Cardiovascular Theme, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Antonios Pantazis
- Division of Neurobiology, Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.,Wallenberg Center for Molecular Medicine, Linköping University, Linköping, Sweden
| | - Hrayr S Karagueuzian
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - James N Weiss
- Department of Medicine (Cardiology), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Riccardo Olcese
- Division of Molecular Medicine, Department of Anesthesiology & Perioperative Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,University of California, Los Angeles Cardiovascular Theme, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA.,Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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7
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Gonano LA, Mattiazzi A. Targeting late ICaL to close the window to ventricular arrhythmias. J Gen Physiol 2021; 153:212726. [PMID: 34699586 PMCID: PMC8552155 DOI: 10.1085/jgp.202113009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Luis A Gonano
- Centro de Investigaciones Cardiovasculares Horacio Cingolani, CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
| | - Alicia Mattiazzi
- Centro de Investigaciones Cardiovasculares Horacio Cingolani, CONICET La Plata, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, Argentina
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8
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Molecular Characterization of Membrane Steroid Receptors in Hormone-Sensitive Cancers. Cells 2021; 10:cells10112999. [PMID: 34831222 PMCID: PMC8616056 DOI: 10.3390/cells10112999] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 10/29/2021] [Accepted: 11/02/2021] [Indexed: 12/20/2022] Open
Abstract
Cancer is one of the most common causes of death worldwide, and its development is a result of the complex interaction of genetic factors, environmental cues, and aging. Hormone-sensitive cancers depend on the action of one or more hormones for their development and progression. Sex steroids and corticosteroids can regulate different physiological functions, including metabolism, growth, and proliferation, through their interaction with specific nuclear receptors, that can transcriptionally regulate target genes via their genomic actions. Therefore, interference with hormones’ activities, e.g., deregulation of their production and downstream pathways or the exposition to exogenous hormone-active substances such as endocrine-disrupting chemicals (EDCs), can affect the regulation of their correlated pathways and trigger the neoplastic transformation. Although nuclear receptors account for most hormone-related biologic effects and their slow genomic responses are well-studied, less-known membrane receptors are emerging for their ability to mediate steroid hormones effects through the activation of rapid non-genomic responses also involved in the development of hormone-sensitive cancers. This review aims to collect pre-clinical and clinical data on these extranuclear receptors not only to draw attention to their emerging role in cancer development and progression but also to highlight their dual role as tumor microenvironment players and potential candidate drug targets.
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Ovics P, Regev D, Baskin P, Davidor M, Shemer Y, Neeman S, Ben-Haim Y, Binah O. Drug Development and the Use of Induced Pluripotent Stem Cell-Derived Cardiomyocytes for Disease Modeling and Drug Toxicity Screening. Int J Mol Sci 2020; 21:E7320. [PMID: 33023024 PMCID: PMC7582587 DOI: 10.3390/ijms21197320] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/23/2020] [Accepted: 09/27/2020] [Indexed: 12/19/2022] Open
Abstract
: Over the years, numerous groups have employed human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) as a superb human-compatible model for investigating the function and dysfunction of cardiomyocytes, drug screening and toxicity, disease modeling and for the development of novel drugs for heart diseases. In this review, we discuss the broad use of iPSC-CMs for drug development and disease modeling, in two related themes. In the first theme-drug development, adverse drug reactions, mechanisms of cardiotoxicity and the need for efficient drug screening protocols-we discuss the critical need to screen old and new drugs, the process of drug development, marketing and Adverse Drug reactions (ADRs), drug-induced cardiotoxicity, safety screening during drug development, drug development and patient-specific effect and different mechanisms of ADRs. In the second theme-using iPSC-CMs for disease modeling and developing novel drugs for heart diseases-we discuss the rationale for using iPSC-CMs and modeling acquired and inherited heart diseases with iPSC-CMs.
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Affiliation(s)
- Paz Ovics
- Department of Physiology, Biophysics and Systems Biology, The Rappaport Institute, Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel; (P.O.); (D.R.); (P.B.); (M.D.); (Y.S.); (S.N.)
| | - Danielle Regev
- Department of Physiology, Biophysics and Systems Biology, The Rappaport Institute, Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel; (P.O.); (D.R.); (P.B.); (M.D.); (Y.S.); (S.N.)
| | - Polina Baskin
- Department of Physiology, Biophysics and Systems Biology, The Rappaport Institute, Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel; (P.O.); (D.R.); (P.B.); (M.D.); (Y.S.); (S.N.)
| | - Mor Davidor
- Department of Physiology, Biophysics and Systems Biology, The Rappaport Institute, Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel; (P.O.); (D.R.); (P.B.); (M.D.); (Y.S.); (S.N.)
| | - Yuval Shemer
- Department of Physiology, Biophysics and Systems Biology, The Rappaport Institute, Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel; (P.O.); (D.R.); (P.B.); (M.D.); (Y.S.); (S.N.)
| | - Shunit Neeman
- Department of Physiology, Biophysics and Systems Biology, The Rappaport Institute, Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel; (P.O.); (D.R.); (P.B.); (M.D.); (Y.S.); (S.N.)
| | - Yael Ben-Haim
- Institute of Molecular and Clinical Sciences, St. George’s University of London, London SW17 0RE, UK;
- Cardiology Clinical Academic Group, St. George’s University Hospitals NHS Foundation Trust, London SW17 0QT, UK
| | - Ofer Binah
- Department of Physiology, Biophysics and Systems Biology, The Rappaport Institute, Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa 31096, Israel; (P.O.); (D.R.); (P.B.); (M.D.); (Y.S.); (S.N.)
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10
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Kistamás K, Veress R, Horváth B, Bányász T, Nánási PP, Eisner DA. Calcium Handling Defects and Cardiac Arrhythmia Syndromes. Front Pharmacol 2020; 11:72. [PMID: 32161540 PMCID: PMC7052815 DOI: 10.3389/fphar.2020.00072] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 01/24/2020] [Indexed: 12/13/2022] Open
Abstract
Calcium ions (Ca2+) play a major role in the cardiac excitation-contraction coupling. Intracellular Ca2+ concentration increases during systole and falls in diastole thereby determining cardiac contraction and relaxation. Normal cardiac function also requires perfect organization of the ion currents at the cellular level to drive action potentials and to maintain action potential propagation and electrical homogeneity at the tissue level. Any imbalance in Ca2+ homeostasis of a cardiac myocyte can lead to electrical disturbances. This review aims to discuss cardiac physiology and pathophysiology from the elementary membrane processes that can cause the electrical instability of the ventricular myocytes through intracellular Ca2+ handling maladies to inherited and acquired arrhythmias. Finally, the paper will discuss the current therapeutic approaches targeting cardiac arrhythmias.
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Affiliation(s)
- Kornél Kistamás
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
| | - Roland Veress
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs Horváth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Tamás Bányász
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Péter P Nánási
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.,Department of Dental Physiology, Faculty of Dentistry, University of Debrecen, Debrecen, Hungary
| | - David A Eisner
- Division of Cardiovascular Sciences, School of Medical Sciences, University of Manchester, Manchester, United Kingdom
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11
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Tejero R, Balk S, Franco-Espin J, Ojeda J, Hennlein L, Drexl H, Dombert B, Clausen JD, Torres-Benito L, Saal-Bauernschubert L, Blum R, Briese M, Appenzeller S, Tabares L, Jablonka S. R-Roscovitine Improves Motoneuron Function in Mouse Models for Spinal Muscular Atrophy. iScience 2020; 23:100826. [PMID: 31981925 PMCID: PMC6992996 DOI: 10.1016/j.isci.2020.100826] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 08/08/2019] [Accepted: 01/06/2020] [Indexed: 12/27/2022] Open
Abstract
Neurotransmission defects and motoneuron degeneration are hallmarks of spinal muscular atrophy, a monogenetic disease caused by the deficiency of the SMN protein. In the present study, we show that systemic application of R-Roscovitine, a Cav2.1/Cav2.2 channel modifier and a cyclin-dependent kinase 5 (Cdk-5) inhibitor, significantly improved survival of SMA mice. In addition, R-Roscovitine increased Cav2.1 channel density and sizes of the motor endplates. In vitro, R-Roscovitine restored axon lengths and growth cone sizes of Smn-deficient motoneurons corresponding to enhanced spontaneous Ca2+ influx and elevated Cav2.2 channel cluster formations independent of its capability to inhibit Cdk-5. Acute application of R-Roscovitine at the neuromuscular junction significantly increased evoked neurotransmitter release, increased the frequency of spontaneous miniature potentials, and lowered the activation threshold of silent terminals. These data indicate that R-Roscovitine improves Ca2+ signaling and Ca2+ homeostasis in Smn-deficient motoneurons, which is generally crucial for motoneuron differentiation, maturation, and function. R-Roscovitine prolongs survival of SMA mice R-Roscovitine increases Ca2+ influx and growth cone size of SMA motoneurons R-Roscovitine beneficially affects neurotransmission in SMA motor nerve terminals R-Roscovitine wakes up dormant synapses of SMA motoneurons
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Affiliation(s)
- Rocio Tejero
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, 41009 Seville, Spain
| | - Stefanie Balk
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Julio Franco-Espin
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, 41009 Seville, Spain
| | - Jorge Ojeda
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, 41009 Seville, Spain
| | - Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Hans Drexl
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Benjamin Dombert
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Jan-Dierk Clausen
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Laura Torres-Benito
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, 41009 Seville, Spain
| | | | - Robert Blum
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Michael Briese
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Silke Appenzeller
- Comprehensive Cancer Center Mainfranken, University Hospital Würzburg, 97080 Würzburg, Germany; Core Unit SysMed, University of Würzburg, 97080 Würzburg, Germany
| | - Lucia Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, University of Seville, 41009 Seville, Spain.
| | - Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany.
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12
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Cernuda B, Fernandes CT, Allam SM, Orzillo M, Suppa G, Chia Chang Z, Athanasopoulos D, Buraei Z. The molecular determinants of R-roscovitine block of hERG channels. PLoS One 2019; 14:e0217733. [PMID: 31479461 PMCID: PMC6719874 DOI: 10.1371/journal.pone.0217733] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 08/17/2019] [Indexed: 02/06/2023] Open
Abstract
Human ether-à-go-go-related gene (Kv11.1, or hERG) is a potassium channel that conducts the delayed rectifier potassium current (IKr) during the repolarization phase of cardiac action potentials. hERG channels have a larger pore than other K+channels and can trap many unintended drugs, often resulting in acquired LQTS (aLQTS). R-roscovitine is a cyclin-dependent kinase (CDK) inhibitor that induces apoptosis in colorectal, breast, prostate, multiple myeloma, other cancer cell lines, and tumor xenografts, in micromolar concentrations. It is well tolerated in phase II clinical trials. R-roscovitine inhibits open hERG channels but does not become trapped in the pore. Two-electrode voltage clamp recordings from Xenopus oocytes expressing wild-type (WT) or hERG pore mutant channels (T623A, S624A, Y652A, F656A) demonstrated that compared to WT hERG, T623A, Y652A, and F656A inhibition by 200 μM R-roscovitine was ~ 48%, 29%, and 73% weaker, respectively. In contrast, S624A hERG was inhibited more potently than WT hERG, with a ~ 34% stronger inhibition. These findings were further supported by the IC50 values, which were increased for T623A, Y652A and F656A (by ~5.5, 2.75, and 42 fold respectively) and reduced 1.3 fold for the S624A mutant. Our data suggest that while T623, Y652, and F656 are critical for R-roscovitine-mediated inhibition, S624 may not be. Docking studies further support our findings. Thus, R-roscovitine’s relatively unique features, coupled with its tolerance in clinical trials, could guide future drug screens.
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Affiliation(s)
- Bryan Cernuda
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Salma Mohamed Allam
- Department of Biology, Pace University, New York, NY, United States of America
| | - Matthew Orzillo
- Department of Biology, Pace University, New York, NY, United States of America
| | - Gabrielle Suppa
- Department of Biology, Pace University, New York, NY, United States of America
| | - Zuleen Chia Chang
- Department of Biology, Pace University, New York, NY, United States of America
| | | | - Zafir Buraei
- Department of Biology, Pace University, New York, NY, United States of America
- * E-mail:
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Hou P, Shi J, White KM, Gao Y, Cui J. ML277 specifically enhances the fully activated open state of KCNQ1 by modulating VSD-pore coupling. eLife 2019; 8:e48576. [PMID: 31329101 PMCID: PMC6684268 DOI: 10.7554/elife.48576] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/22/2019] [Indexed: 12/16/2022] Open
Abstract
Upon membrane depolarization, the KCNQ1 potassium channel opens at the intermediate (IO) and activated (AO) states of the stepwise voltage-sensing domain (VSD) activation. In the heart, KCNQ1 associates with KCNE1 subunits to form IKs channels that regulate heart rhythm. KCNE1 suppresses the IO state so that the IKs channel opens only to the AO state. Here, we tested modulations of human KCNQ1 channels by an activator ML277 in Xenopus oocytes. It exclusively changes the pore opening properties of the AO state without altering the IO state, but does not affect VSD activation. These observations support a distinctive mechanism responsible for the VSD-pore coupling at the AO state that is sensitive to ML277 modulation. ML277 provides insights and a tool to investigate the gating mechanism of KCNQ1 channels, and our study reveals a new strategy for treating long QT syndrome by specifically enhancing the AO state of native IKs currents.
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Affiliation(s)
- Panpan Hou
- Department of Biomedical EngineeringWashington UniversitySt. LouisUnited States
- Center for the Investigation of Membrane Excitability DisordersWashington UniversitySt. LouisUnited States
- Cardiac Bioelectricity and Arrhythmia CenterWashington UniversitySt. LouisUnited States
| | - Jingyi Shi
- Department of Biomedical EngineeringWashington UniversitySt. LouisUnited States
- Center for the Investigation of Membrane Excitability DisordersWashington UniversitySt. LouisUnited States
- Cardiac Bioelectricity and Arrhythmia CenterWashington UniversitySt. LouisUnited States
| | - Kelli McFarland White
- Department of Biomedical EngineeringWashington UniversitySt. LouisUnited States
- Center for the Investigation of Membrane Excitability DisordersWashington UniversitySt. LouisUnited States
- Cardiac Bioelectricity and Arrhythmia CenterWashington UniversitySt. LouisUnited States
| | | | - Jianmin Cui
- Department of Biomedical EngineeringWashington UniversitySt. LouisUnited States
- Center for the Investigation of Membrane Excitability DisordersWashington UniversitySt. LouisUnited States
- Cardiac Bioelectricity and Arrhythmia CenterWashington UniversitySt. LouisUnited States
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Giudicessi JR, Ackerman MJ. Calcium Revisited: New Insights Into the Molecular Basis of Long-QT Syndrome. Circ Arrhythm Electrophysiol 2018; 9:CIRCEP.116.002480. [PMID: 27390209 DOI: 10.1161/circep.116.002480] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 05/27/2016] [Indexed: 12/12/2022]
Affiliation(s)
- John R Giudicessi
- From the Internal Medicine Residency and Clinician-Investigator Programs, Department of Medicine (J.R.G.) and Departments of Cardiovascular Diseases, Pediatrics (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (M.J.A.), Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN
| | - Michael J Ackerman
- From the Internal Medicine Residency and Clinician-Investigator Programs, Department of Medicine (J.R.G.) and Departments of Cardiovascular Diseases, Pediatrics (Division of Pediatric Cardiology), and Molecular Pharmacology & Experimental Therapeutics (M.J.A.), Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN.
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15
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Abstract
L-type calcium channel CaV1.2 plays an essential role in cardiac function. The gain-of-function mutations in CaV1.2 have been reported to be associated with Timothy syndrome, a disease characterized by QT prolongation and syndactyly. Previously we demonstrated that roscovitine, a cyclin-dependent kinase (CDK) inhibitor, could rescue the phenotypes in induced pluripotent stem cell-derived cardiomyocytes from Timothy syndrome patients. However, exactly how roscovitine rescued the phenotypes remained unclear. Here we report a mechanism potentially underlying the therapeutic effects of roscovitine on Timothy syndrome cardiomyocytes. Our results using roscovitine analogs and CDK inhibitors and constructs demonstrated that roscovitine exhibits its therapeutic effects in part by inhibiting CDK5. The outcomes of this study allowed us to identify a molecular mechanism whereby CaV1.2 channels are regulated by CDK5. This study provides insights into the regulation of cardiac calcium channels and the development of future therapeutics for Timothy syndrome patients. CDK5 Inhibition alleviates the phenotypes in Timothy syndrome cardiomyocytes CDK5 regulates the functions of CaV1.2 channels in cardiomyocytes
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16
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Assembly of functionally integrated human forebrain spheroids. Nature 2017; 545:54-59. [PMID: 28445465 PMCID: PMC5805137 DOI: 10.1038/nature22330] [Citation(s) in RCA: 774] [Impact Index Per Article: 110.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Accepted: 04/04/2017] [Indexed: 12/12/2022]
Abstract
The development of the nervous system involves a coordinated succession
of events including the migration of GABAergic neurons from ventral to dorsal
forebrain and their integration into cortical circuits. However, these
interregional interactions have not yet been modelled with human cells. Here, we
generate from human pluripotent cells three-dimensional spheroids resembling
either the dorsal or ventral forebrain and containing cortical glutamatergic or
GABAergic neurons. These subdomain-specific forebrain spheroids can be assembled
to recapitulate the saltatory migration of interneurons similar to migration in
fetal forebrain. Using this system, we find that in Timothy syndrome– a
neurodevelopmental disorder that is caused by mutations in the CaV1.2
calcium channel, interneurons display abnormal migratory saltations. We also
show that after migration, interneurons functionally integrate with
glutamatergic neurons to form a microphysiological system. We anticipate that
this approach will be useful for studying development and disease, and for
deriving spheroids that resemble other brain regions to assemble circuits
in vitro.
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Liu N, Yang Y, Ge L, Liu M, Colecraft HM, Liu X. Cooperative and acute inhibition by multiple C-terminal motifs of L-type Ca 2+ channels. eLife 2017; 6. [PMID: 28059704 PMCID: PMC5279948 DOI: 10.7554/elife.21989] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 01/05/2017] [Indexed: 12/31/2022] Open
Abstract
Inhibitions and antagonists of L-type Ca2+ channels are important to both research and therapeutics. Here, we report C-terminus mediated inhibition (CMI) for CaV1.3 that multiple motifs coordinate to tune down Ca2+ current and Ca2+ influx toward the lower limits determined by end-stage CDI (Ca2+-dependent inactivation). Among IQV (preIQ3-IQ domain), PCRD and DCRD (proximal or distal C-terminal regulatory domain), spatial closeness of any two modules, e.g., by constitutive fusion, facilitates the trio to form the complex, compete against calmodulin, and alter the gating. Acute CMI by rapamycin-inducible heterodimerization helps reconcile the concurrent activation/inactivation attenuations to ensure Ca2+ influx is reduced, in that Ca2+ current activated by depolarization is potently (~65%) inhibited at the peak (full activation), but not later on (end-stage inactivation, ~300 ms). Meanwhile, CMI provides a new paradigm to develop CaV1 inhibitors, the therapeutic potential of which is implied by computational modeling of CaV1.3 dysregulations related to Parkinson’s disease. DOI:http://dx.doi.org/10.7554/eLife.21989.001 All cells need calcium ions to stay healthy, but having too many calcium ions can interfere with important processes in the cell and cause severe problems. Proteins known as calcium channels on the cell surface allow calcium ions to flow into the cell from the surrounding environment. Cells carefully control the opening and closing of these channels to prevent too many calcium ions entering the cell at once. CaV1.3 channels are a type of calcium channel that are important for the heart and brain to work properly. Defects in CaV1.3 channels can lead to irregular heart rhythms and neurodegenerative diseases such as Parkinson’s disease. Studies have shown that part of the CaV1.3 channel that sits inside the cell – known as the “tail” – responds to increases in the levels of calcium ions inside the cell by closing the channel. The tail region of CaV1.3 contains three modules, but how these modules work together to regulate channel activity is not clear. Liu, Yang et al. investigated whether the three modules need to be physically connected to each other in the channel protein. For the experiments, several versions of the protein were constructed with different combinations of tail modules being directly linked as part of the same molecule or present as separate molecules. When any two modules were directly linked, the third module could bind to them and this was enough to close the CaV1.3 channel. However, the channel did not close if the modules were totally isolated from each other as three separate molecules. Certain types of neurons in the brain produce electrical signals in a rhythmic fashion that depends on CaV1.3 channels. In Parkinson’s disease, increased movement of calcium ions into these neurons via CaV1.3 channels interferes with the rhythms of the signals and can cause these cells to die. Liu, Yang et al. performed computer simulations to analyse the effects of closing CaV1.3 channels in these neurons. The results suggest that this can restore normal rhythms of electrical activity and prevent these cells from dying. The next step is to understand the molecular details of how the tail region closes CaV1.3 channels and its role in healthy and diseased cells. This may lead to new ways to block CaV1.3 channels in different types of diseases. DOI:http://dx.doi.org/10.7554/eLife.21989.002
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Affiliation(s)
- Nan Liu
- X-Lab for Transmembrane Signaling Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Yaxiong Yang
- X-Lab for Transmembrane Signaling Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Lin Ge
- X-Lab for Transmembrane Signaling Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Min Liu
- X-Lab for Transmembrane Signaling Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Henry M Colecraft
- Department of Physiology and Cellular Biophysics, Columbia University, New York, United States
| | - Xiaodong Liu
- X-Lab for Transmembrane Signaling Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China.,School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, China
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18
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Bohnen MS, Peng G, Robey SH, Terrenoire C, Iyer V, Sampson KJ, Kass RS. Molecular Pathophysiology of Congenital Long QT Syndrome. Physiol Rev 2017; 97:89-134. [PMID: 27807201 PMCID: PMC5539372 DOI: 10.1152/physrev.00008.2016] [Citation(s) in RCA: 114] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ion channels represent the molecular entities that give rise to the cardiac action potential, the fundamental cellular electrical event in the heart. The concerted function of these channels leads to normal cyclical excitation and resultant contraction of cardiac muscle. Research into cardiac ion channel regulation and mutations that underlie disease pathogenesis has greatly enhanced our knowledge of the causes and clinical management of cardiac arrhythmia. Here we review the molecular determinants, pathogenesis, and pharmacology of congenital Long QT Syndrome. We examine mechanisms of dysfunction associated with three critical cardiac currents that comprise the majority of congenital Long QT Syndrome cases: 1) IKs, the slow delayed rectifier current; 2) IKr, the rapid delayed rectifier current; and 3) INa, the voltage-dependent sodium current. Less common subtypes of congenital Long QT Syndrome affect other cardiac ionic currents that contribute to the dynamic nature of cardiac electrophysiology. Through the study of mutations that cause congenital Long QT Syndrome, the scientific community has advanced understanding of ion channel structure-function relationships, physiology, and pharmacological response to clinically employed and experimental pharmacological agents. Our understanding of congenital Long QT Syndrome continues to evolve rapidly and with great benefits: genotype-driven clinical management of the disease has improved patient care as precision medicine becomes even more a reality.
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Affiliation(s)
- M S Bohnen
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - G Peng
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - S H Robey
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - C Terrenoire
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - V Iyer
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - K J Sampson
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
| | - R S Kass
- Department of Pharmacology, Columbia University Medical Center, New York, New York; and The New York Stem Cell Foundation Research Institute, New York, New York
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19
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Coskun V, Lombardo DM. Studying the pathophysiologic connection between cardiovascular and nervous systems using stem cells. J Neurosci Res 2016; 94:1499-1510. [PMID: 27629698 DOI: 10.1002/jnr.23924] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/25/2016] [Accepted: 08/25/2016] [Indexed: 12/17/2022]
Abstract
The cardiovascular and nervous systems are deeply connected during development, health, and disease. Both systems affect and regulate the development of each other during embryogenesis and the early postnatal period. Specialized neural crest cells contribute to cardiac structures, and a number of growth factors released from the cardiac tissue (e.g., glial cell line-derived neurotrophic factor, neurturin, nerve growth factor, Neurotrophin-3) ensure proper maturation of the incoming parasympathetic and sympathetic neurons. Physiologically, the cardiovascular and nervous systems operate in harmony to adapt to various physical and emotional conditions to maintain homeostasis through sympathetic and parasympathetic nervous systems. Moreover, neurocardiac regulation involves a neuroaxis consisting of cortex, amygdala, and other subcortical structures, which have the ability to modify lower-level neurons in the hierarchy. Given the interconnectivity of cardiac and neural systems, when one undergoes pathological changes, the other is affected to a certain extent. In addition, there are specific neurocardiac diseases that affect both systems simultaneously, such as Huntington disease, Lewy body diseases, Friedreich ataxia, congenital heart diseases, Danon disease, and Timothy syndrome. Over the last decade, in vitro modeling of neurocardiac diseases using induced pluripotent stem cells (iPSCs) has provided an invaluable opportunity to elevate our knowledge about the brain-heart connection, since previously primary cardiomyocytes and neurons had been extremely difficult to maintain long-term in vitro. Ultimately, the ability of iPSC technology to model abnormal functional phenotypes of human neurocardiac disorders, combined with the ease of therapeutic screening using this approach, will transform patient care through personalized medicine in the future. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Volkan Coskun
- Department of Medicine, Division of Cardiology, University of California, Irvine, Irvine, California.
| | - Dawn M Lombardo
- Department of Medicine, Division of Cardiology, University of California, Irvine, Irvine, California
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20
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Norez C, Vandebrouck C, Bertrand J, Noel S, Durieu E, Oumata N, Galons H, Antigny F, Chatelier A, Bois P, Meijer L, Becq F. Roscovitine is a proteostasis regulator that corrects the trafficking defect of F508del-CFTR by a CDK-independent mechanism. Br J Pharmacol 2015; 171:4831-49. [PMID: 25065395 DOI: 10.1111/bph.12859] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 03/07/2014] [Accepted: 04/10/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE The most common mutation in cystic fibrosis (CF), F508del, causes defects in trafficking, channel gating and endocytosis of the CF transmembrane conductance regulator (CFTR) protein. Because CF is an orphan disease, therapeutic strategies aimed at improving mutant CFTR functions are needed to target the root cause of CF. EXPERIMENTAL APPROACH Human CF airway epithelial cells were treated with roscovitine 100 μM for 2 h before CFTR maturation, expression and activity were examined. The mechanism of action of roscovitine was explored by recording the effect of depleting endoplasmic reticulum (ER) Ca(2+) on the F508del-CFTR/calnexin interaction and by measuring proteasome activity. KEY RESULTS Of the cyclin-dependent kinase (CDK) inhibitors investigated, roscovitine was found to restore the cell surface expression and defective channel function of F508del-CFTR in human CF airway epithelial cells. Neither olomoucine nor (S)-CR8, two very efficient CDK inhibitors, corrected F508del-CFTR trafficking demonstrating that the correcting effect of roscovitine was independent of CDK inhibition. Competition studies with inhibitors of the ER quality control (ERQC) indicated that roscovitine acts on the calnexin pathway and on the degradation machinery. Roscovitine was shown (i) to partially inhibit the interaction between F508del-CFTR and calnexin by depleting ER Ca(2+) and (ii) to directly inhibit the proteasome activity in a Ca(2+) -independent manner. CONCLUSIONS AND IMPLICATIONS Roscovitine is able to correct the defective function of F508del-CFTR by preventing the ability of the ERQC to interact with and degrade F508del-CFTR via two synergistic but CDK-independent mechanisms. Roscovitine has potential as a pharmacological therapy for CF.
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Affiliation(s)
- C Norez
- Institut de Physiologie et Biologie Cellulaires, Université de Poitiers, Poitiers, France
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The role of L-type voltage-gated calcium channels Cav1.2 and Cav1.3 in normal and pathological brain function. Cell Tissue Res 2014; 357:463-76. [DOI: 10.1007/s00441-014-1936-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 05/27/2014] [Indexed: 10/25/2022]
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Tamma G, Ranieri M, Di Mise A, Spirlì A, Russo A, Svelto M, Valenti G. Effect of roscovitine on intracellular calcium dynamics: differential enantioselective responses. Mol Pharm 2013; 10:4620-8. [PMID: 24168213 DOI: 10.1021/mp400430t] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cyclin-dependent kinases (CDKs) inhibitors have emerged as interesting therapeutic candidates. Of these, (S)-roscovitine has been proposed as potential neuroprotective molecule for stroke while (R)-roscovitine is currently entering phase II clinical trials against cancers and phase I clinical tests against glomerulonephritis. In addition, (R)-roscovitine has been suggested as potential antihypertensive and anti-inflammatory drug. Dysfunction of intracellular calcium balance is a common denominator of these diseases, and the two roscovitine enantiomers (S and R) are known to modulate calcium voltage channel activity differentially. Here, we provide a detailed description of short- and long-term responses of roscovitine on intracellular calcium handling in renal epithelial cells. Short-term exposure to (S)-roscovitine induced a cytosolic calcium peak, which was abolished after stores depletion with cyclopiazonic acid (CPA). Instead, (R)-roscovitine caused a calcium peak followed by a small calcium plateau. Cytosolic calcium response was prevented after stores depletion. Bafilomycin, a selective vacuolar H(+)-ATPase inhibitor, abolished the small calcium plateau. Long-term exposure to (R)-roscovitine significantly reduced the basal calcium level compared to control and (S)-roscovitine treated cells. However, both enantiomers increased calcium accumulation in the endoplasmic reticulum (ER). Consistently, cells treated with (R)-roscovitine showed a significant increase in SERCA activity, whereas (S)-roscovitine incubation resulted in a reduced PMCA expression. We also found a tonic decreased ability to release calcium from the ER, likely via IP3 signaling, under treatment with (S)- or (R)-roscovitine. Together our data revealed that (S)-roscovitine and (R)-roscovitine exert distinct enantiospecific effects on intracellular calcium signaling in renal epithelial cells. This distinct pharmacological profile can be relevant for roscovitine clinical use.
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Affiliation(s)
- Grazia Tamma
- Department of Biosciences, Biotechnologies and Biopharmaceutics and ∥Centre of Excellence Genomic and Proteomics GEBCA, University of Bari , Italy
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Abstract
Genetic mutations in ion channel genes that are associated with cardiac arrhythmias have been identified over the past several decades. However, little is known about the pathophysiological processes. An important limitation has been the difficulty of using human cardiomyocytes to study arrhythmias and identify drugs. To circumvent this issue, we have developed a method using human-induced pluripotent stem cells to generate cardiomyocytes from individuals with Timothy syndrome (TS), a genetic disorder characterized by QT prolongation, ventricular tachycardia, and autism. The TS ventricular-like cardiomyocytes exhibit deficits in contraction, electrical signaling, and calcium handling, as revealed by live cell imaging and electrophysiological studies. We tested candidate drugs in TS cardiomyocytes and found that roscovitine could successfully rescue these cellular phenotypes. The use of a human cellular model of cardiac arrhythmias provides a useful new platform not only to study disease mechanisms but also to develop new therapies to treat cardiac arrhythmias.
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Stockner T, Koschak A. What can naturally occurring mutations tell us about Ca(v)1.x channel function? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1598-607. [PMID: 23219801 PMCID: PMC3787742 DOI: 10.1016/j.bbamem.2012.11.026] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 11/16/2012] [Accepted: 11/17/2012] [Indexed: 11/18/2022]
Abstract
Voltage-gated Ca2 + channels allow for Ca2 +-dependent intracellular signaling by directly mediating Ca2 + ion influx, by physical coupling to intracellular Ca2 + release channels or functional coupling to other ion channels such as Ca2 + activated potassium channels. L-type Ca2 + channels that comprise the family of Cav1 channels are expressed in many electrically excitable tissues and are characterized by their unique sensitivity to dihydropyridines. In this issue, we summarize genetic defects in L-type Ca2 + channels and analyze their role in human diseases (Ca2 + channelopathies); e.g. mutations in Cav1.2 α1 cause Timothy and Brugada syndrome, mutations in Cav1.3 α1 are linked to sinoatrial node dysfunction and deafness while mutations in Cav1.4 α1 are associated with X-linked retinal disorders such as an incomplete form of congenital stationary night blindness. Herein, we also put the mutations underlying the channel's dysfunction into the structural context of the pore-forming α1 subunit. This analysis highlights the importance of combining functional data with structural analysis to gain a deeper understanding for the disease pathophysiology as well as for physiological channel function. This article is part of a Special Issue entitled: Calcium channels.
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Affiliation(s)
- Thomas Stockner
- Medical University Vienna, Center for Physiology and Pharmacology, Department of Pharmacology, Währingerstrasse 13A, 1090 Vienna, Austria
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Cohen-Kutner M, Yahalom Y, Trus M, Atlas D. Calcineurin Controls Voltage-Dependent-Inactivation (VDI) of the Normal and Timothy Cardiac Channels. Sci Rep 2012; 2:366. [PMID: 22511998 PMCID: PMC3328044 DOI: 10.1038/srep00366] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 03/22/2012] [Indexed: 12/25/2022] Open
Abstract
Ca2+-entry in the heart is tightly controlled by Cav1.2 inactivation, which involves Ca2+-dependent inactivation (CDI) and voltage-dependent inactivation (VDI) components. Timothy syndrome, a subtype-form of congenital long-QT syndrome, results from a nearly complete elimination of VDI by the G406R mutation in the α11.2 subunit of Cav1.2. Here, we show that a single (A1929P) or a double mutation (H1926A-H1927A) within the CaN-binding site at the human C-terminal tail of α11.2, accelerate the inactivation rate and enhances VDI of both wt and Timothy channels. These results identify the CaN-binding site as the long-sought VDI-regulatory motif of the cardiac channel. The substantial increase in VDI and the accelerated inactivation caused by the selective inhibitors of CaN, cyclosporine A and FK-506, which act at the same CaN-binding site, further support this conclusion. A reversal of enhanced-sympathetic tone by VDI-enhancing CaN inhibitors could be beneficial for improving Timothy syndrome complications such as long-QT and autism.
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26
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Yarotskyy V, Gao G, Peterson BZ, Elmslie KS. Domain III regulates N-type (CaV2.2) calcium channel closing kinetics. J Neurophysiol 2011; 107:1942-51. [PMID: 22205645 DOI: 10.1152/jn.00993.2011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ca(V)2.2 (N-type) and Ca(V)1.2 (L-type) calcium channels gate differently in response to membrane depolarization, which is critical to the unique physiological functions mediated by these channels. We wondered if the source for these differences could be identified. As a first step, we examined the effect of domain exchange between N-type and L-type channels on activation-deactivation kinetics, which were significantly different between these channels. Kinetic analysis of chimeric channels revealed N-channel-like deactivation for all chimeric channels containing N-channel domain III, while activation appeared to be a more distributed function across domains. This led us to hypothesize that domain III was an important regulator of N-channel closing. This idea was further examined with R-roscovitine, which is a trisubstituted purine that slows N-channel deactivation by exclusively binding to activated N-channels. L-channels lack this response to roscovitine, which allowed us to use N-L chimeras to test the role of domain III in roscovitine modulation of N-channel deactivation. In support of our hypothesis, all chimeric channels containing the N-channel domain III responded to roscovitine with slowed deactivation, while those chimeric channels with L-channel domain III did not. Thus a combination of kinetic and pharmacological evidence supports the hypothesis that domain III is an important regulator of N-channel closing. Our results support specialization of gating functions among calcium channel domains.
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Affiliation(s)
- Viktor Yarotskyy
- Dept. of Pharmacology, Kirksville Coll. of Osteopathic Medicine, AT Still Univ., 800 W. Jefferson St., Kirksville, MO 63501, USA
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Paşca SP, Portmann T, Voineagu I, Yazawa M, Shcheglovitov O, Paşca AM, Cord B, Palmer TD, Chikahisa S, Seiji N, Bernstein JA, Hallmayer J, Geschwind DH, Dolmetsch RE. Using iPSC-derived neurons to uncover cellular phenotypes associated with Timothy syndrome. Nat Med 2011; 17:1657-62. [PMID: 22120178 PMCID: PMC3517299 DOI: 10.1038/nm.2576] [Citation(s) in RCA: 466] [Impact Index Per Article: 35.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 10/18/2011] [Indexed: 02/06/2023]
Abstract
Monogenic neurodevelopmental disorders provide key insights into the pathogenesis of disease and help us understand how specific genes control the development of the human brain. Timothy syndrome is caused by a missense mutation in the L-type calcium channel Ca(v)1.2 that is associated with developmental delay and autism. We generated cortical neuronal precursor cells and neurons from induced pluripotent stem cells derived from individuals with Timothy syndrome. Cells from these individuals have defects in calcium (Ca(2+)) signaling and activity-dependent gene expression. They also show abnormalities in differentiation, including decreased expression of genes that are expressed in lower cortical layers and in callosal projection neurons. In addition, neurons derived from individuals with Timothy syndrome show abnormal expression of tyrosine hydroxylase and increased production of norepinephrine and dopamine. This phenotype can be reversed by treatment with roscovitine, a cyclin-dependent kinase inhibitor and atypical L-type-channel blocker. These findings provide strong evidence that Ca(v)1.2 regulates the differentiation of cortical neurons in humans and offer new insights into the causes of autism in individuals with Timothy syndrome.
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Affiliation(s)
- Sergiu P. Paşca
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, USA
| | - Thomas Portmann
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, USA
| | - Irina Voineagu
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Masayuki Yazawa
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, USA
| | - Oleksandr Shcheglovitov
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, USA
| | - Anca M. Paşca
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, USA
| | - Branden Cord
- Department of Neurology, Stanford University School of Medicine, Stanford, California, USA
| | - Theo D. Palmer
- Department of Neurology, Stanford University School of Medicine, Stanford, California, USA
| | - Sachiko Chikahisa
- Department of Psychiatry & Behavioral Science, Stanford University School of Medicine, Stanford, California, USA
| | - Nishino Seiji
- Department of Psychiatry & Behavioral Science, Stanford University School of Medicine, Stanford, California, USA
| | - Jonathan A. Bernstein
- Department of Pediatrics, Stanford University School of Medicine, Stanford, California, USA
| | - Joachim Hallmayer
- Department of Psychiatry & Behavioral Science, Stanford University School of Medicine, Stanford, California, USA
| | - Daniel H. Geschwind
- Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Ricardo E. Dolmetsch
- Department of Neurobiology, Stanford University School of Medicine, Stanford, California, USA
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Yarotskyy V, Elmslie KS. Roscovitine inhibits CaV3.1 (T-type) channels by preferentially affecting closed-state inactivation. J Pharmacol Exp Ther 2011; 340:463-72. [PMID: 22088954 DOI: 10.1124/jpet.111.187104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
T-type calcium channels (Ca(V)3) play an important role in many physiological and pathological processes, including cancerogenesis. Ca(V)3 channel blockers have been proposed as potential cancer treatments. Roscovitine, a trisubstituted purine, is a cyclin-dependent kinase (CDK) inhibitor that is currently undergoing phase II clinical trials as an anticancer drug and has been shown to affect calcium and potassium channel activity. Here, we investigate the effect of roscovitine on Ca(V)3.1 channels. Ca(V)3.1 channels were transiently expressed in human embryonic kidney 293 cells, and currents were recorded by using the whole-cell patch-clamp technique. Roscovitine blocks Ca(V)3.1 channels with higher affinity for depolarized cells (EC₅₀ of 10 μM), which is associated with a negative shift in the voltage dependence of closed-state inactivation. Enhanced inactivation is mediated by roscovitine-induced acceleration of closed-state inactivation and slowed recovery from inactivation. Small effects of roscovitine were also observed on T-channel deactivation and open-state inactivation, but neither could explain the inhibitory effect. Roscovitine inhibits Ca(V)3.1 channels within the therapeutic range (10-50 μM) in part by stabilizing the closed-inactivated state. The ability of roscovitine to block multiple mediators of proliferation, including CDKs and Ca(V)3.1 channels, may facilitate its anticancer properties.
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Affiliation(s)
- Viktor Yarotskyy
- Department of Pharmacology and Physiology, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Using induced pluripotent stem cells to investigate cardiac phenotypes in Timothy syndrome. Nature 2011; 471:230-4. [PMID: 21307850 PMCID: PMC3077925 DOI: 10.1038/nature09855] [Citation(s) in RCA: 483] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 01/21/2011] [Indexed: 12/22/2022]
Abstract
Individuals with congenital or acquired prolongation of the QT interval, or long QT syndrome (LQTS), are at risk of life threatening ventricular arrhythmia 1, 2. LQTS is commonly genetic in origin but can also be caused or exacerbated by environmental factors1, 3. A missense mutation in the L-type calcium channel CaV1.2 leads to LQTS in patients with Timothy syndrome (TS)4, 5. To explore the effect of the TS mutation on the electrical activity and contraction of human cardiomyocytes (CMs), we reprogrammed human skin cells from TS patients to generate induced pluripotent stem cells (iPSCs), and differentiated these cells into CMs. Electrophysiological recording and calcium (Ca2+) imaging studies of these cells revealed irregular contraction, excess Ca2+ influx, prolonged action potentials, irregular electrical activity and abnormal calcium transients in ventricular-like cells. We found that roscovitine (Ros), a compound that increases the voltage-dependent inactivation (VDI) of CaV1.26–8, restored the electrical and Ca2+ signaling properties of CMs from TS patients. This study opens new avenues for studying the molecular and cellular mechanisms of cardiac arrhythmias in humans, and provides a robust assay for developing new drugs to treat these diseases.
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