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Hazan S, Tauber M, Ben-Chaim Y. Voltage dependence of M2 muscarinic receptor antagonists and allosteric modulators. Biochem Pharmacol 2024; 227:116421. [PMID: 38996933 DOI: 10.1016/j.bcp.2024.116421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/12/2024] [Accepted: 07/09/2024] [Indexed: 07/14/2024]
Abstract
Muscarinic receptors are G protein-coupled receptors (GPCRs) that play a role in various physiological functions. Previous studies have shown that these receptors, along with other GPCRs, are voltage-sensitive; both their affinity toward agonists and their activation are regulated by membrane potential. To our knowledge, whether the effect of antagonists on these receptors is voltage-dependent has not yet been studied. In this study, we used Xenopus oocytes expressing the M2 muscarinic receptor (M2R) to investigate this question. Our results indicate that the potencies of two M2R antagonists, atropine and scopolamine, are voltage-dependent; they are more effective at resting potential than under depolarization. In contrast, the M2R antagonist AF-DX 386 did not exhibit voltage-dependent potency.Furthermore, we discovered that the voltage dependence of M2R activation by acetylcholine remains unchanged in the presence of two allosteric modulators, the negative modulator gallamine and the positive modulator LY2119620. These findings enhance our understanding of GPCRs' voltage dependence and may have pharmacological implications.
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Affiliation(s)
- Shimrit Hazan
- Department of Natural Sciences, The Open University of Israel, Ra'anana, Israel
| | - Merav Tauber
- Department of Natural Sciences, The Open University of Israel, Ra'anana, Israel
| | - Yair Ben-Chaim
- Department of Natural Sciences, The Open University of Israel, Ra'anana, Israel.
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Zeng MT, Huang LY, Zheng XH, Fu YQ, Weng CF. Ethanolic Extracts of Cupressaceae Species Conifers Provide Rapid Protection against Barium Chloride-Induced Cardiac Arrhythmia. Pharmaceuticals (Basel) 2024; 17:1003. [PMID: 39204108 PMCID: PMC11356987 DOI: 10.3390/ph17081003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2024] [Revised: 07/16/2024] [Accepted: 07/22/2024] [Indexed: 09/03/2024] Open
Abstract
Sudden cardiac death (SCD) is responsible for a high percentage of cardiovascular fatalities, with ventricular arrhythmias being the most common cause. Despite numerous clinically available antiarrhythmic drugs (AADs), AADs retain some undesirable arrhythmic effects, and their inappropriate use can lead to severe adverse reactions. The exploration of new therapeutic options against arrhythmias with fewer unreceptive effects is of utmost importance. The ethanolic extracts of seven Cupressaceae species, namely, Chamaecyparis obtusa, Juniperus chinensis (L.) Ant., Sabina chinensis (L.) Ant. cv. Kaizuca, Platycladus orientalis (L.) Franco, Juniperus sabina L., Fokienia hodginsii, and Juniperus chinensis 'Pyramidalis' were investigated for their pharmacological effects on barium chloride (BaCl2)-induced arrhythmia using normal II lead electrocardiogram (ECG) measurements in a mouse model. According to the ECG profiles, pretreatment with C. obtusa, P. orientalis, and J. sabina extracts provoked dose-dependent protection against BaCl2-induced arrhythmia, while pretreatment with the other four species and amiodarone did not exert cardioprotective effects. The treatment effects were confirmed using a rat model. The therapeutic effects of C. obtusa, P. orientalis, and J. sabina extracts on the M2 and M3 receptors but not the M1 receptor were mediated by the inhibition of the M2 receptor blocker (methoctramine tetrahydrochloride), M3 antagonist (4-DAMP), or M1 receptor blocker (pirenzepine dihydrochloride). This first-line evidence illustrates that certain Cupressaceae species possess active antiarrhythmic components. The first line of key findings revealed that active components of certain Cupressaceae species have cardioprotective effects, suggesting that these innovative phytochemicals have promising potential for preventing the occurrence of cardiac arrhythmia and reducing sudden cardiac death.
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Affiliation(s)
- Meng-Ting Zeng
- Functional Physiology Section, Department of Basic Medical Science, Xiamen Medical College, Xiamen 361023, China; (M.-T.Z.); (L.-Y.H.); (X.-H.Z.); (Y.-Q.F.)
| | - Li-Yue Huang
- Functional Physiology Section, Department of Basic Medical Science, Xiamen Medical College, Xiamen 361023, China; (M.-T.Z.); (L.-Y.H.); (X.-H.Z.); (Y.-Q.F.)
| | - Xiao-Hui Zheng
- Functional Physiology Section, Department of Basic Medical Science, Xiamen Medical College, Xiamen 361023, China; (M.-T.Z.); (L.-Y.H.); (X.-H.Z.); (Y.-Q.F.)
| | - Yan-Qi Fu
- Functional Physiology Section, Department of Basic Medical Science, Xiamen Medical College, Xiamen 361023, China; (M.-T.Z.); (L.-Y.H.); (X.-H.Z.); (Y.-Q.F.)
| | - Ching-Feng Weng
- Functional Physiology Section, Department of Basic Medical Science, Xiamen Medical College, Xiamen 361023, China; (M.-T.Z.); (L.-Y.H.); (X.-H.Z.); (Y.-Q.F.)
- Institute of Respiratory Disease, Department of Basic Medical Science, Xiamen Medical College, Xiamen 361023, China
- LEADTEK Research, Inc., New Taipei City 235603, Taiwan
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Tauber M, Ben-Chaim Y. Voltage Sensors Embedded in G Protein-Coupled Receptors. Int J Mol Sci 2024; 25:5295. [PMID: 38791333 PMCID: PMC11120775 DOI: 10.3390/ijms25105295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 05/08/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
Some signaling processes mediated by G protein-coupled receptors (GPCRs) are modulated by membrane potential. In recent years, increasing evidence that GPCRs are intrinsically voltage-dependent has accumulated. A recent publication challenged the view that voltage sensors are embedded in muscarinic receptors. Herein, we briefly discuss the evidence that supports the notion that GPCRs themselves are voltage-sensitive proteins and an alternative mechanism that suggests that voltage-gated sodium channels are the voltage-sensing molecules involved in such processes.
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Affiliation(s)
| | - Yair Ben-Chaim
- Department of Natural Sciences, The Open University of Israel, Ra’anana 4353701, Israel
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Tauber M, Ben-Chaim Y. Functional consequences of a rare human serotonergic 5-HT 1A receptor variant. Front Pharmacol 2023; 14:1270726. [PMID: 37795037 PMCID: PMC10547147 DOI: 10.3389/fphar.2023.1270726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/08/2023] [Indexed: 10/06/2023] Open
Abstract
Serotonin (5-HT) plays a central role in various brain functions via the activation of a family of receptors, most of them G protein coupled receptors (GPCRs). 5-HT1A receptor, the most abundant 5-HT receptors, was implicated in many brain dysfunctions and is a major target for drug discovery. Several genetic polymorphisms within the 5-HT1A receptor gene were identified and linked to different conditions, including anxiety and depression. Here, we used Xenopus oocytes to examine the effects of one of the functional polymorphism, Arg220Leu, on the function of the receptor. We found that the mutated receptor shows normal activation of G protein and normal 5-HT binding. On the other hand, the mutated receptor shows impaired desensitization, probably due to impairment in activation of β arrestin-dependent pathway. Furthermore, while the 5-HT1A receptor was shown to exhibit voltage dependent activation by serotonin and by buspirone, the mutated receptor was voltage-independent. Our results suggest a pronounced effect of the mutation on the function of the 5-HT1A receptor and add to our understanding of the molecular mechanism of its voltage dependence. Moreover, the findings of this study may suggest a functional explanation for the possible link between this variant and brain pathologies.
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Affiliation(s)
| | - Yair Ben-Chaim
- Department of Natural Sciences, The Open University of Israel, Ra’anana, Israel
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David D, Bentulila Z, Tauber M, Ben-Chaim Y. G Protein-Coupled Receptors Regulated by Membrane Potential. Int J Mol Sci 2022; 23:ijms232213988. [PMID: 36430466 PMCID: PMC9696401 DOI: 10.3390/ijms232213988] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022] Open
Abstract
G protein-coupled receptors (GPCRs) are involved in a vast majority of signal transduction processes. Although they span the cell membrane, they have not been considered to be regulated by the membrane potential. Numerous studies over the last two decades have demonstrated that several GPCRs, including muscarinic, adrenergic, dopaminergic, and glutamatergic receptors, are voltage regulated. Following these observations, an effort was made to elucidate the molecular basis for this regulatory effect. In this review, we will describe the advances in understanding the voltage dependence of GPCRs, the suggested molecular mechanisms that underlie this phenomenon, and the possible physiological roles that it may play.
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López-Serrano AL, Zamora-Cárdenas R, Aréchiga-Figueroa IA, Salazar-Fajardo PD, Ferrer T, Alamilla J, Sánchez-Chapula JA, Navarro-Polanco RA, Moreno-Galindo EG. Differential voltage-dependent modulation of the ACh-gated K+ current by adenosine and acetylcholine. PLoS One 2022; 17:e0261960. [PMID: 35030226 PMCID: PMC8759768 DOI: 10.1371/journal.pone.0261960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 12/14/2021] [Indexed: 11/18/2022] Open
Abstract
Inhibitory regulation of the heart is determined by both cholinergic M2 receptors (M2R) and adenosine A1 receptors (A1R) that activate the same signaling pathway, the ACh-gated inward rectifier K+ (KACh) channels via Gi/o proteins. Previously, we have shown that the agonist-specific voltage sensitivity of M2R underlies several voltage-dependent features of IKACh, including the ‘relaxation’ property, which is characterized by a gradual increase or decrease of the current when cardiomyocytes are stepped to hyperpolarized or depolarized voltages, respectively. However, it is unknown whether membrane potential also affects A1R and how this could impact IKACh. Upon recording whole-cell currents of guinea-pig cardiomyocytes, we found that stimulation of the A1R-Gi/o-IKACh pathway with adenosine only caused a very slight voltage dependence in concentration-response relationships (~1.2-fold EC50 increase with depolarization) that was not manifested in the relative affinity, as estimated by the current deactivation kinetics (τ = 4074 ± 214 ms at -100 mV and τ = 4331 ± 341 ms at +30 mV; P = 0.31). Moreover, IKACh did not exhibit relaxation. Contrarily, activation of the M2R-Gi/o-IKACh pathway with acetylcholine induced the typical relaxation of the current, which correlated with the clear voltage-dependent effect observed in the concentration-response curves (~2.8-fold EC50 increase with depolarization) and in the IKACh deactivation kinetics (τ = 1762 ± 119 ms at -100 mV and τ = 1503 ± 160 ms at +30 mV; P = 0.01). Our findings further substantiate the hypothesis of the agonist-specific voltage dependence of GPCRs and that the IKACh relaxation is consequence of this property.
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Affiliation(s)
- Ana Laura López-Serrano
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | - Rodrigo Zamora-Cárdenas
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | - Iván A. Aréchiga-Figueroa
- CONACYT, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, S.L.P., Mexico
| | | | - Tania Ferrer
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | - Javier Alamilla
- CONACYT, Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | - José A. Sánchez-Chapula
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | | | - Eloy G. Moreno-Galindo
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
- * E-mail:
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Chen X, Bründl M, Friesacher T, Stary-Weinzinger A. Computational Insights Into Voltage Dependence of Polyamine Block in a Strong Inwardly Rectifying K + Channel. Front Pharmacol 2020; 11:721. [PMID: 32499707 PMCID: PMC7243266 DOI: 10.3389/fphar.2020.00721] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Accepted: 04/30/2020] [Indexed: 12/30/2022] Open
Abstract
Inwardly rectifying potassium (KIR) channels play important roles in controlling cellular excitability and K+ ion homeostasis. Under physiological conditions, KIR channels allow large K+ influx at potentials negative to the equilibrium potential of K+ but permit little outward current at potentials positive to the equilibrium potential of K+, due to voltage dependent block of outward K+ flux by cytoplasmic polyamines. These polycationic molecules enter the KIR channel pore from the intracellular side. They block K+ ion movement through the channel at depolarized potentials, thereby ensuring, for instance, the long plateau phase of the cardiac action potential. Key questions concerning how deeply these charged molecules migrate into the pore and how the steep voltage dependence arises remain unclear. Recent MD simulations on GIRK2 (=Kir3.2) crystal structures have provided unprecedented details concerning the conduction mechanism of a KIR channel. Here, we use MD simulations with applied field to provide detailed insights into voltage dependent block of putrescine, using the conductive state of the strong inwardly rectifying K+ channel GIRK2 as starting point. Our µs long simulations elucidate details about binding sites of putrescine in the pore and suggest that voltage-dependent rectification arises from a dual mechanism.
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López-Serrano AL, De Jesús-Pérez JJ, Zamora-Cárdenas R, Ferrer T, Rodríguez-Menchaca AA, Tristani-Firouzi M, Moreno-Galindo EG, Navarro-Polanco RA. Voltage-induced structural modifications on M2 muscarinic receptor and their functional implications when interacting with the superagonist iperoxo. Biochem Pharmacol 2020; 177:113961. [PMID: 32272111 DOI: 10.1016/j.bcp.2020.113961] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 04/02/2020] [Indexed: 12/31/2022]
Abstract
It has been reported that muscarinic type-2 receptors (M2R) are voltage sensitive in an agonist-specific manner. In this work, we studied the effects of membrane potential on the interaction of M2R with the superagonist iperoxo (IXO), both functionally (using the activation of the ACh-gated K+ current (IKACh) in cardiomyocytes) and by molecular dynamics (MD) simulations. We found that IXO activated IKACh with remarkable high potency and clear voltage dependence, displaying a larger effect at the hyperpolarized potential. This result is consistent with a greater affinity, as validated by a slower (τ = 14.8 ± 2.3 s) deactivation kinetics of the IXO-evoked IKACh than that at the positive voltage (τ = 6.7 ± 1.2 s). The voltage-dependent M2R-IXO interaction induced IKACh to exhibit voltage-dependent features of this current, such as the 'relaxation gating' and the modulation of rectification. MD simulations revealed that membrane potential evoked specific conformational changes both at the external access and orthosteric site of M2R that underlie the agonist affinity change provoked by voltage on M2R. Moreover, our experimental data suggest that the 'tyrosine lid' (Y104, Y403, and Y426) is not the previously proposed voltage sensor of M2R. These findings provide an insight into the structural and functional framework of the biased signaling induced by voltage on GPCRs.
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Affiliation(s)
- Ana Laura López-Serrano
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | - José J De Jesús-Pérez
- Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico; Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Rodrigo Zamora-Cárdenas
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | - Tania Ferrer
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico
| | - Aldo A Rodríguez-Menchaca
- Departamento de Fisiología y Biofísica, Facultad de Medicina, Universidad Autónoma de San Luis Potosí, San Luis Potosí, SLP, Mexico
| | - Martin Tristani-Firouzi
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA; Division of Pediatric Cardiology, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Eloy G Moreno-Galindo
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, Col., Mexico.
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Pingyu Z, Binglei J, Qilong J, Tao W, Wei T. Cyclic Stretch Promotes Proliferation and Contraction of Human Bladder Smooth Muscle Cells by Cajal-Mediated c-kit Expression in Interstitial Cells. Med Sci Monit 2019; 25:4784-4792. [PMID: 31249285 PMCID: PMC6612242 DOI: 10.12659/msm.917549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background The present study was performed to assess the effect of mechanical stretch on the proliferation and contractile function of hBSMCs. Material/Methods hBSMCs and ICCs were seeded at 8×104 cells/well in 6-well silicone elastomer-bottomed culture plates coated with type I collagen, and grown to 80% confluence in DMEM/10% FBS and a 5% CO2 humidified atmosphere at 37°C. Cells of hBSMCs and hBSMCs/ICCs of co-culture were then subjected to continuous cycles of stretch-relaxation using a computer-driven, stretch-inducing device. The treated concentration of imatinib was 10 μM. Mechanisms underlying observed hBSMCs contraction were examined using Western blotting and RT-PCR. The 0.1 μM carbachol was separately added to the experimental groups, and 300 s was recorded by laser scanning confocal microscope. Results We found that mechanical stretch increased contraction and proliferation of hBSMCs. Calcium ion activity increased significantly after mechanical stretch. The number of hBSMCs was significantly increased after the combination mechanical stretch with ICCs treatment. After combination mechanical stretch with hBSMCs/ICCs treatment, the mRNA and protein level of M2, M3, and c-kit were significantly increased. After combination of mechanical stretch with no imatinib treatment, the proliferation of hBSMCs was higher than others, and the mRNA and protein level of M2 and M3 were significantly increased. Conclusions We revealed that ICCs could promote hBSMC proliferation and contraction, and cyclic stretch could promote acetylcholine receptor M2 and M3 caused by c-kit in the ICCs, which promoted the contraction of hBSMCs.
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Affiliation(s)
- Zhu Pingyu
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China (mainland).,Department of Urology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China (mainland)
| | - Jiang Binglei
- Department of Ultrasound, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China (mainland)
| | - Jiang Qilong
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China (mainland)
| | - Wu Tao
- Department of Urology, Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, China (mainland)
| | - Tang Wei
- Department of Urology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China (mainland)
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