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Bukiya AN, Dopico AM. Cholesterol antagonism of alcohol inhibition of smooth muscle BK channel requires cell integrity and involves a protein kinase C-dependent mechanism(s). Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1866:158874. [PMID: 33383194 DOI: 10.1016/j.bbalip.2020.158874] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 12/13/2020] [Accepted: 12/22/2020] [Indexed: 10/22/2022]
Abstract
Alcohol constricts cerebral arteries via inhibition of voltage/calcium-gated, large conductance potassium (BK) channels in vascular myocytes. Using a rat model of high-cholesterol (high-CLR) diet and CLR enrichment of cerebral arteries in vitro, we recently showed that CLR protected against alcohol-induced constriction of cerebral arteries. The subcellular mechanism(s) underlying CLR protection against alcohol-induced constriction of the artery is unclear. Here we use a rat model of high-CLR diet and patch-clamp recording of BK channels in inside-out patches from cerebral artery myocytes to demonstrate that this diet antagonizes inhibition of BK currents by 50 mM ethanol. High-CLR-driven protection against alcohol inhibition of BK currents is reversed following CLR depletion in vitro. Similar to CLR accumulation in vivo, pre-incubation of arterial myocytes from normocholesterolemic rats in CLR-enriching media in vitro protects against alcohol-induced inhibition of BK current. However, application of CLR-enriching media to cell-free membrane patches does not protect against the alcohol effect. These different outcomes point to the involvement of cell signaling in CLR-alcohol interaction on BK channels. Incubation of myocytes with the PKC activators phorbol 12-myristate 13-acetate or 1,2-dioctanoyl-sn-glycerol, but not with the PKC inhibitor Gouml 6983, prior to patch excision precludes CLR enrichment from antagonizing alcohol action. Thus, PKC activation either disables the CLR target(s) or competes with elevated CLR. Favoring the latter possibility, 1,2-dioctanoyl-sn-glycerol protects against alcohol-induced inhibition of BK currents in patches from myocytes with naïve CLR. Our findings document that CLR antagonism of alcohol-induced BK channel inhibition requires cell integrity and is enabled by a PKC-dependent mechanism(s).
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Affiliation(s)
- Anna N Bukiya
- Dept. Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, United States.
| | - Alex M Dopico
- Dept. Pharmacology, Addiction Science, and Toxicology, College of Medicine, The University of Tennessee Health Science Center, Memphis, TN, United States
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Jiang Q, Li K, Lu WJ, Li S, Chen X, Liu XJ, Yuan J, Ding Q, Lan F, Cai SQ. Identification of small-molecule ion channel modulators in C. elegans channelopathy models. Nat Commun 2018; 9:3941. [PMID: 30258187 PMCID: PMC6158242 DOI: 10.1038/s41467-018-06514-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 08/31/2018] [Indexed: 02/07/2023] Open
Abstract
Ion channels are important therapeutic targets, but the discovery of ion channel drugs remains challenging due to a lack of assays that allow high-throughput screening in the physiological context. Here we report C. elegans phenotype-based methods for screening ion channel drugs. Expression of modified human ether-a-go-go-related gene (hERG) potassium channels in C. elegans results in egg-laying and locomotive defects, which offer indicators for screening small-molecule channel modulators. Screening in worms expressing hERGA561V, which carries a trafficking-defective mutation A561V known to associate with long-QT syndrome, identifies two functional correctors Prostratin and ingenol-3,20-dibenzoate. These compounds activate PKCε signaling and consequently phosphorylate S606 at the pore region of the channel to promote hERGA561V trafficking to the plasma membrane. Importantly, the compounds correct electrophysiological abnormalities in hiPSC-derived cardiomyocytes bearing a heterozygous CRISPR/Cas9-edited hERGA561V. Thus, we have developed an in vivo high-throughput method for screening compounds that have therapeutic potential in treating channelopathies. Mutations in the voltage-gated K+ channel human ether-a-go-go-related gene (hERG) lead to Long-QT syndrome, causing life-threatening cardiac arrhythmia. Here the authors use C. elegans as a platform to run a channelopathy drug screen, identifying drugs to target hERG mutants.
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Affiliation(s)
- Qiang Jiang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Kai Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Wen-Jing Lu
- Beijing Laboratory for Cardiovascular Precision Medicine, Beijing Anzhen Hospital, Capital Medical University, 100029, Beijing, China
| | - Shuang Li
- University of Chinese Academy of Sciences, 100049, Beijing, China.,CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Xin Chen
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China.,Developmental and Stem Cell Program, Arthur and Sonia Labatt Brain Tumor Research Centre, Hospital for Sick Children, Toronto, M5G 1X8, ON, Canada
| | - Xi-Juan Liu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, China
| | - Jie Yuan
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, China.,University of Chinese Academy of Sciences, 100049, Beijing, China
| | - Qiurong Ding
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, China
| | - Feng Lan
- Beijing Laboratory for Cardiovascular Precision Medicine, Beijing Anzhen Hospital, Capital Medical University, 100029, Beijing, China.
| | - Shi-Qing Cai
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 200031, Shanghai, China.
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Liu X, Wang Y, Zhang H, Shen L, Xu Y. Different protein kinase C isoenzymes mediate inhibition of cardiac rapidly activating delayed rectifier K + current by different G-protein coupled receptors. Br J Pharmacol 2017; 174:4464-4477. [PMID: 28941256 DOI: 10.1111/bph.14049] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 09/15/2017] [Accepted: 09/18/2017] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Elevated angiotensin II (Ang II) and sympathetic activity contributes to a high risk of ventricular arrhythmias in heart disease. The rapidly activating delayed rectifier K+ current (IKr ) carried by the hERG channels plays a critical role in cardiac repolarization, and decreased IKr is involved in increased cardiac arrhythmogenicity. Stimulation of α1A -adrenoreceptors or angiotensin II AT1 receptors is known to inhibit IKr via PKC. Here, we have identified the PKC isoenzymes mediating the inhibition of IKr by activation of these two different GPCRs. EXPERIMENTAL APPROACH The whole-cell patch-clamp technique was used to record IKr in guinea pig cardiomyocytes and HEK293 cells co-transfected with hERG and α1A -adrenoreceptor or AT1 receptor genes. KEY RESULTS A broad spectrum PKC inhibitor Gö6983 (not inhibiting PKCε), a selective cPKC inhibitor Gö6976 and a PKCα-specific inhibitor peptide, blocked the inhibition of IKr by the α1A -adrenoreceptor agonist A61603. However, these inhibitors did not affect the reduction of IKr by activation of AT1 receptors, whereas the PKCε-selective inhibitor peptide did block the effect. The effects of angiotensin II and the PKCε activator peptide were inhibited in mutant hERG channels in which 17 of the 18 PKC phosphorylation sites were deleted, whereas a deletion of the N-terminus of the hERG channels selectively prevented the inhibition elicited by A61603 and the cPKC activator peptide. CONCLUSIONS AND IMPLICATIONS Our results indicated that inhibition of IKr by activation of α1A -adrenoreceptors or AT1 receptors were mediated by PKCα and PKCε isoforms respectively, through different molecular mechanisms.
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Affiliation(s)
- Xueli Liu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China; The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China; The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,Hebei Institute for Drug Control, Shijiazhuang, China
| | - Yuhong Wang
- Institute of Masteria Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Hua Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China; The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China; The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China
| | - Li Shen
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China; The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China; The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China
| | - Yanfang Xu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China; The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China; The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China
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