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Lertwanakarn T, Suntravat M, Sánchez EE, Wolska BM, Solaro RJ, de Tombe PP, Tachampa K. Negative inotropic mechanisms of β-cardiotoxin in cardiomyocytes by depression of myofilament ATPase activity without activation of the classical β-adrenergic pathway. Sci Rep 2021; 11:21154. [PMID: 34707114 PMCID: PMC8551325 DOI: 10.1038/s41598-021-00282-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 10/06/2021] [Indexed: 11/09/2022] Open
Abstract
Beta-cardiotoxin (β-CTX) from the king cobra venom (Ophiophagus hannah) was previously proposed as a novel β-adrenergic blocker. However, the involvement of β-adrenergic signaling by this compound has never been elucidated. The objectives of this study were to investigate the underlying mechanisms of β-CTX as a β-blocker and its association with the β-adrenergic pathway. The effects of β-CTX on isolated cardiac myocyte functions, calcium homeostasis, the phosphorylation level of targeted proteins, and the myofibrillar ATPase activity were studied. Healthy Sprague Dawley rats were used for cardiomyocytes isolation. Like propranolol, β-CTX attenuated the cardiomyocyte inotropy and calcium transient alterations as induced by isoproterenol stimulation. In contrast, these effects were not observed in forskolin-treated cells. Interestingly, cardiomyocytes treated with β-CTX showed no changes in phosphorylation level at any PKA-targeted sites in the myofilaments as demonstrated in Western blot analysis. The skinned fibers study revealed no change in myofilament kinetics by β-CTX. However, this protein exhibited the direct inhibition of myofibrillar ATPase activity with calcium de-sensitization of the enzyme. In summary, the negative inotropic mechanism of β-CTX was discovered. β-CTX exhibits an atypical β-blocker mechanism. These properties of β-CTX may benefit in developing a novel agent aid to treat hypertrophic cardiomyopathy.
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Affiliation(s)
- Tuchakorn Lertwanakarn
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Montamas Suntravat
- National Natural Toxins Research Center, Texas-A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Elda E Sánchez
- National Natural Toxins Research Center, Texas-A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Beata M Wolska
- Department of Physiology and Biophysics, the University of Illinois at Chicago, Chicago, IL, USA.,Department of Medicine, the University of Illinois at Chicago, Chicago, IL, USA
| | - R John Solaro
- Department of Physiology and Biophysics, the University of Illinois at Chicago, Chicago, IL, USA
| | - Pieter P de Tombe
- Department of Physiology and Biophysics, the University of Illinois at Chicago, Chicago, IL, USA.,Phymedexp, Université de Montpellier, Inserm, CNRS, Montpellier, France
| | - Kittipong Tachampa
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand.
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Averin AS, Utkin YN. Cardiovascular Effects of Snake Toxins: Cardiotoxicity and Cardioprotection. Acta Naturae 2021; 13:4-14. [PMID: 34707893 PMCID: PMC8526186 DOI: 10.32607/actanaturae.11375] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/13/2021] [Indexed: 12/11/2022] Open
Abstract
Snake venoms, as complex mixtures of peptides and proteins, affect various vital systems of the organism. One of the main targets of the toxic components from snake venoms is the cardiovascular system. Venom proteins and peptides can act in different ways, exhibiting either cardiotoxic or cardioprotective effects. The principal classes of these compounds are cobra cardiotoxins, phospholipases A2, and natriuretic, as well as bradykinin-potentiating peptides. There is another group of proteins capable of enhancing angiogenesis, which include, e.g., vascular endothelial growth factors possessing hypotensive and cardioprotective activities. Venom proteins and peptides exhibiting cardiotropic and vasoactive effects are promising candidates for the design of new drugs capable of preventing or constricting the development of pathological processes in cardiovascular diseases, which are currently the leading cause of death worldwide. For example, a bradykinin-potentiating peptide from Bothrops jararaca snake venom was the first snake venom compound used to create the widely used antihypertensive drugs captopril and enalapril. In this paper, we review the current state of research on snake venom components affecting the cardiovascular system and analyse the mechanisms of physiological action of these toxins and the prospects for their medical application.
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Affiliation(s)
- A. S. Averin
- Institute of Cell Biophysics of the Russian Academy of Sciences PSCBR RAS, Pushchino, Moscow region, 142290 Russia
| | - Yu. N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997 Russia
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Trim CM, Byrne LJ, Trim SA. Utilisation of compounds from venoms in drug discovery. PROGRESS IN MEDICINAL CHEMISTRY 2021; 60:1-66. [PMID: 34147202 DOI: 10.1016/bs.pmch.2021.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Difficult drug targets are becoming the normal course of business in drug discovery, sometimes due to large interacting surfaces or only small differences in selectivity regions. For these, a different approach is merited: compounds lying somewhere between the small molecule and the large antibody in terms of many properties including stability, biodistribution and pharmacokinetics. Venoms have evolved over millions of years to be complex mixtures of stable molecules derived from other somatic molecules, the stability comes from the pressure to be ready for delivery at a moment's notice. Snakes, spiders, scorpions, jellyfish, wasps, fish and even mammals have evolved independent venom systems with complex mixtures in their chemical arsenal. These venom-derived molecules have been proven to be useful tools, such as for the development of antihypotensive angiotensin converting enzyme (ACE) inhibitors and have also made successful drugs such as Byetta® (Exenatide), Integrilin® (Eptifibatide) and Echistatin. Only a small percentage of the available chemical space from venoms has been investigated so far and this is growing. In a new era of biological therapeutics, venom peptides present opportunities for larger target engagement surface with greater stability than antibodies or human peptides. There are challenges for oral absorption and target engagement, but there are venom structures that overcome these and thus provide substrate for engineering novel molecules that combine all desired properties. Venom researchers are characterising new venoms, species, and functions all the time, these provide great substrate for solving the challenges presented by today's difficult targets.
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Affiliation(s)
- Carol M Trim
- Faculty of Science, Engineering and Social Sciences, Natural and Applied Sciences, School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury, Kent, United Kingdom
| | - Lee J Byrne
- Faculty of Science, Engineering and Social Sciences, Natural and Applied Sciences, School of Psychology and Life Sciences, Canterbury Christ Church University, Canterbury, Kent, United Kingdom
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Nirthanan S. Snake three-finger α-neurotoxins and nicotinic acetylcholine receptors: molecules, mechanisms and medicine. Biochem Pharmacol 2020; 181:114168. [PMID: 32710970 DOI: 10.1016/j.bcp.2020.114168] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022]
Abstract
Snake venom three-finger α-neurotoxins (α-3FNTx) act on postsynaptic nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junction (NMJ) to produce skeletal muscle paralysis. The discovery of the archetypal α-bungarotoxin (α-BgTx), almost six decades ago, exponentially expanded our knowledge of membrane receptors and ion channels. This included the localisation, isolation and characterization of the first receptor (nAChR); and by extension, the pathophysiology and pharmacology of neuromuscular transmission and associated pathologies such as myasthenia gravis, as well as our understanding of the role of α-3FNTxs in snakebite envenomation leading to novel concepts of targeted treatment. Subsequent studies on a variety of animal venoms have yielded a plethora of novel toxins that have revolutionized molecular biomedicine and advanced drug discovery from bench to bedside. This review provides an overview of nAChRs and their subtypes, classification of α-3FNTxs and the challenges of typifying an increasing arsenal of structurally and functionally unique toxins, and the three-finger protein (3FP) fold in the context of the uPAR/Ly6/CD59/snake toxin superfamily. The pharmacology of snake α-3FNTxs including their mechanisms of neuromuscular blockade, variations in reversibility of nAChR interactions, specificity for nAChR subtypes or for distinct ligand-binding interfaces within a subtype and the role of α-3FNTxs in neurotoxic envenomation are also detailed. Lastly, a reconciliation of structure-function relationships between α-3FNTx and nAChRs, derived from historical mutational and biochemical studies and emerging atomic level structures of nAChR models in complex with α-3FNTxs is discussed.
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Affiliation(s)
- Selvanayagam Nirthanan
- School of Medical Science, Griffith Health Group, Griffith University, Gold Coast, Queensland, Australia.
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Lertwanakarn T, Suntravat M, Sanchez EE, Boonhoh W, Solaro RJ, Wolska BM, Martin JL, de Tombe PP, Tachampa K. Suppression of cardiomyocyte functions by β-CTX isolated from the Thai king cobra ( Ophiophagus hannah) venom via an alternative method. J Venom Anim Toxins Incl Trop Dis 2020; 26:e20200005. [PMID: 32742278 PMCID: PMC7375408 DOI: 10.1590/1678-9199-jvatitd-2020-0005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 06/16/2020] [Indexed: 12/20/2022] Open
Abstract
Background Beta-cardiotoxin (β-CTX), the three-finger toxin isolated from king cobra (Ophiophagus hannah) venom, possesses β-blocker activity as indicated by its negative chronotropy and its binding property to both β-1 and β-2 adrenergic receptors and has been proposed as a novel β-blocker candidate. Previously, β-CTX was isolated and purified by FPLC. Here, we present an alternative method to purify this toxin. In addition, we tested its cytotoxicity against different mammalian muscle cell types and determined the impact on cardiac function in isolated cardiac myocyte so as to provide insights into the pharmacological action of this protein. Methods β-CTX was isolated from the crude venom of the Thai king cobra using reverse-phased and cation exchange HPLC. In vitro cellular viability MTT assays were performed on mouse myoblast (C2C12), rat smooth muscle (A7r5), and rat cardiac myoblast (H9c2) cells. Cell shortening and calcium transient dynamics were recorded on isolated rat cardiac myocytes over a range of β-CTX concentration. Results Purified β-CTX was recovered from crude venom (0.53% w/w). MTT assays revealed 50% cytotoxicity on A7r5 cells at 9.41 ± 1.14 µM (n = 3), but no cytotoxicity on C2C12 and H9c2 cells up to 114.09 µM. β-CTX suppressed the extend of rat cardiac cell shortening in a dose-dependent manner; the half-maximal inhibition concentration was 95.97 ± 50.10 nM (n = 3). In addition, the rates of cell shortening and re-lengthening were decreased in β-CTX treated myocytes concomitant with a prolongation of the intracellular calcium transient decay, indicating depression of cardiac contractility secondary to altered cardiac calcium homeostasis. Conclusion We present an alternative purification method for β-CTX from king cobra venom. We reveal cytotoxicity towards smooth muscle and depression of cardiac contractility by this protein. These data are useful to aid future development of pharmacological agents derived from β-CTX.
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Affiliation(s)
- Tuchakorn Lertwanakarn
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - Montamas Suntravat
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Elda E Sanchez
- National Natural Toxins Research Center, Texas A&M University-Kingsville, Kingsville, TX, USA.,Department of Chemistry, Texas A&M University-Kingsville, Kingsville, TX, USA
| | - Worakan Boonhoh
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
| | - R John Solaro
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Beata M Wolska
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA.,Department of Medicine, University of Illinois at Chicago, IL, USA
| | - Jody L Martin
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Pieter P de Tombe
- Department of Physiology and Biophysics, University of Illinois at Chicago, IL, USA
| | - Kittipong Tachampa
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, Thailand
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