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Árpádffy-Lovas T, Mohammed ASA, Naveed M, Koncz I, Baláti B, Bitay M, Jost N, Nagy N, Baczkó I, Virág L, Varró A. Species dependent differences in the inhibition of various potassium currents and in their effects on repolarization in cardiac ventricular muscle. Can J Physiol Pharmacol 2022; 100:880-889. [PMID: 35442802 DOI: 10.1139/cjpp-2022-0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Even though rodents are accessible model animals, their electrophysiological properties are deeply different from that of human, making the translation of rat studies to human rather difficult. We compared the mechanisms of ventricular repolarization in various animal models to those of human by measuring cardiac ventricular action potentials from ventricular papillary muscle preparations using conventional microelectrodes, and applying selective inhibitors of various potassium transmembrane ion currents. Inhibition of the IK1 current (10 µM barium chloride) significantly prolonged rat ventricular repolarization, but only slightly prolonged it in dog, and did not affect it in human. On the contrary, IKr inhibition (50 nM dofetilide) significantly prolonged repolarization in human, rabbit, and dog, but not in rat. Inhibition of the IKur current (1 µM XEN-D0101) only prolonged rat ventricular repolarization, and had no effect in human or dog. Inhibition of the IKs (500 nM HMR-1556) and Ito currents (100 µM chromanol-293B) elicited similar effects in all investigated species. We conclude that dog ventricular preparations have the strongest, and rat ventricular preparations have the weakest translational value in cardiac electrophysiological experiments.
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Affiliation(s)
- Tamás Árpádffy-Lovas
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Aiman Saleh A Mohammed
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Muhammad Naveed
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - István Koncz
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Beáta Baláti
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - Miklós Bitay
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Cardiac Surgery, Second Department of Internal Medicine and Cardiology Center, Szeged, Csongrád, Hungary;
| | - Norbert Jost
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary.,Eötvös Loránd Research Network, 579839, ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary, Budapest, Hungary;
| | - Norbert Nagy
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharamacotherapy, Szeged, Csongrád, Hungary.,Eötvös Loránd Research Network, 579839, ELKH-SZTE Research Group of Cardiovascular Pharmacology, Szeged, Hungary, Budapest, Hungary;
| | - István Baczkó
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - László Virág
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary;
| | - András Varró
- University of Szeged Albert Szent-Györgyi Faculty of Medicine, 37443, Department of Pharmacology and Pharmacotherapy, Szeged, Csongrád, Hungary.,Eötvös Loránd Research Network, 579839, ELKH-SZTE Research Group of Cardiovascular Pharmacology, Budapest, Hungary;
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Deng Z, Wang Y, Shi W, Zhou L, Xu S, Li J, Zhang Y. Haplopelma hainanum venom induces inflammatory skin lesions. PeerJ 2020; 8:e8264. [PMID: 31942253 PMCID: PMC6956770 DOI: 10.7717/peerj.8264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 11/21/2019] [Indexed: 11/20/2022] Open
Abstract
The Haplopelma hainanum is a species of theraphosid spider from China. Its large size and charming appearance make this species a popular pet. According to a previous study, theraphosid spider bites can induce pain, erythema, and edema in humans and can present more severely in domestic animals. The pathological consequences of envenomation by H. hainanum remain unclear. In this study, we investigated the effects and mechanisms of H. hainanum envenomation in mice. We showed that the venom induced slight swelling, intense inflammatory response, and increased the microvascular density in mice skin. Moreover, we found that 50 µg/ml of the spider’s venom induced IL-1β expression in both HaCaT cells and fibroblast cells, but repressed CXCL10 expression in fibroblasts. The venom significantly induced cell senescence and repressed cell proliferation and migration in both HaCaT cells and fibroblast cells. Finally, we examined the expression of Nav channel in HaCaT and fibroblast cells and found that H. hainanum venom effectively inhibited Na+ currents in HaCaT cells. Our study calls for further investigation of the pathological consequences and potential mechanisms of H. hainanum envenomation. This information might assist in the development of suitable therapy.
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Affiliation(s)
- Zhili Deng
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Central South University, Changsha, China.,Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yaling Wang
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China
| | - Wei Shi
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Lei Zhou
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China
| | - San Xu
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Central South University, Changsha, China.,Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Ji Li
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Central South University, Changsha, China.,Center for Molecular Medicine, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yiya Zhang
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
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Zhang Y, Luo J, He J, Rong M, Zeng X. JZTX-V Targets the Voltage Sensor in Kv4.2 to Inhibit I to Potassium Channels in Cardiomyocytes. Front Pharmacol 2019; 10:357. [PMID: 31040778 PMCID: PMC6476928 DOI: 10.3389/fphar.2019.00357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 03/21/2019] [Indexed: 12/16/2022] Open
Abstract
Kv4 potassium channels are responsible for transient outward K+ currents in the cardiac action potential (AP). Previous experiments by our group demonstrated that Jingzhaotoxin-V (JZTX-V) selectively inhibits A-type potassium channels. However, the specific effects of JZTX-V on the transient outward (Ito) current of cardiomyocytes and underlying mechanism of action remain unclear. In the current study, 100 nM JZTX-V effectively inhibited the Ito current and extended the action potential duration (APD) of neonatal rat ventricular myocytes (NRVM). We further analyzed the effects of JZTX-V on Kv4.2, a cloned channel believed to underlie the Ito current in rat cardiomyocytes. JZTX-V inhibited the Kv4.2 current with a half-maximal inhibitory concentration (IC50) of 13 ± 1.7 nM. To establish the molecular mechanism underlying the inhibitory action of JZTX-V on Kv4.2, we performed alanine scanning mutagenesis of Kv4.2 and JZTX-V and assessed the effects of the mutations on binding activities of the proteins. Interestingly, the Kv4.2 mutations V285A, F289A, and V290A reduced the affinity for JZTX-V while I275A and L277A increased the affinity for JZTX-V. Moreover, mutation of positively charged residues (R20 and K22) of JZTX-V and the hydrophobic patch (formed by W5, M6, and W7) led to a significant reduction in toxin sensitivity, indicating that the hydrophobic patch and electrostatic interactions played key roles in the binding of JZTX-V with Kv4.2. Data from our study have shed light on the specific roles and molecular mechanisms of JZTX-V in the regulation of Ito potassium channels and supported its utility as a potential novel antiarrhythmic drug.
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Affiliation(s)
- Yiya Zhang
- Department of Dermatology, Xiangya Hospital, Central South University, Changsha, China.,Key Laboratory of Organ Injury, Aging and Regenerative Medicine of Hunan Province, Central South University, Changsha, China.,The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Ji Luo
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Juan He
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Mingqiang Rong
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Xiongzhi Zeng
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
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