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Zuhra K, Szabo C. The two faces of cyanide: an environmental toxin and a potential novel mammalian gasotransmitter. FEBS J 2022; 289:2481-2515. [PMID: 34297873 PMCID: PMC9291117 DOI: 10.1111/febs.16135] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/15/2021] [Accepted: 07/22/2021] [Indexed: 12/16/2022]
Abstract
Cyanide is traditionally viewed as a cytotoxic agent, with its primary mode of action being the inhibition of mitochondrial Complex IV (cytochrome c oxidase). However, recent studies demonstrate that the effect of cyanide on Complex IV in various mammalian cells is biphasic: in lower concentrations (nanomolar to low micromolar) cyanide stimulates Complex IV activity, increases ATP production and accelerates cell proliferation, while at higher concentrations (high micromolar to low millimolar) it produces the previously known ('classic') toxic effects. The first part of the article describes the cytotoxic actions of cyanide in the context of environmental toxicology, and highlights pathophysiological conditions (e.g., cystic fibrosis with Pseudomonas colonization) where bacterially produced cyanide exerts deleterious effects to the host. The second part of the article summarizes the mammalian sources of cyanide production and overviews the emerging concept that mammalian cells may produce cyanide, in low concentrations, to serve biological regulatory roles. Cyanide fulfills many of the general criteria as a 'classical' mammalian gasotransmitter and shares some common features with the current members of this class: nitric oxide, carbon monoxide, and hydrogen sulfide.
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Affiliation(s)
- Karim Zuhra
- Chair of PharmacologySection of MedicineUniversity of FribourgSwitzerland
| | - Csaba Szabo
- Chair of PharmacologySection of MedicineUniversity of FribourgSwitzerland
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Ozolu RI, Okolie NP, Ebeigbe AB, Karikari N. Effects of sub-chronic oral cyanide on endothelial function in rabbit aortic rings. Hum Exp Toxicol 2016; 26:105-10. [PMID: 17370868 DOI: 10.1177/0960327107071865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have investigated how the endothelium affects vascular responses following sub-chronic low dose cyanide administration. Cyanide exists in low levels in cassava foods, which are widely consumed in tropical Africa. Adult rabbits were administered 0.38 mg/kg per day KCN po for 25 days, and responses of the isolated aortic rings to noradrenaline (NA), calcium chloride (Ca2+) and acetylcholine (ACh) were measured in vitro in the presence and absence of the endothelium. In order to establish that the dose was not toxic, animal weight, some haematological indices, plasma alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured. Results show that endothelium denudation significantly (P <0.05) attenuates NA-induced contraction in rings from cyanide-treated rabbits. There was a similar reduction in response in Ca2+-depleted NA-precontracted endothelium-denuded aortic rings from cyanide-treated rabbits. Endothelium-denuded rings from cyanide-treated rabbits showed significantly (P <0.05) enhanced relaxation to ACh. In rings from control animals, the responses to NA and Ca2+ were not significantly altered, whether in the presence or absence of the endothelium. There were no significant changes in the studied toxicological indices. We conclude that endothelial compromise is necessary for low-dose sub-chronic cyanide-induced to alter vascular reactivity to NA and ACh. Human & Experimental Toxicology (2007) 26, 105-110
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Affiliation(s)
- R I Ozolu
- Department of Pharmacology and Toxicology, University of Benin, Benin City, Nigeria.
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Dong Y, Zhang W, Lai B, Luan WJ, Zhu YH, Zhao BQ, Zheng P. Two free radical pathways mediate chemical hypoxia-induced glutamate release in synaptosomes from the prefrontal cortex. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1823:493-504. [PMID: 22057390 DOI: 10.1016/j.bbamcr.2011.10.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 10/17/2011] [Accepted: 10/17/2011] [Indexed: 10/15/2022]
Abstract
It has been known that the inhibition of mitochondrial cytochrome c oxidase is one of the earliest events occurring under hypoxia and this inhibition can lead to neuronal damages. Thus, the cytochrome c oxidase inhibitor sodium cyanide (NaCN) is widely used to produce a model of chemical hypoxia by inhibiting this enzyme. However, the downstream signaling pathways of the inhibition of the cytochrome c oxidase remain to be studied. In the present paper, we used sodium cyanide to mimic the inhibition of the mitochondrial cytochrome c oxidase and studied its effect on glutamate release in synaptosomes from the prefrontal cortex using on-line fluorimetry. We also further investigated the mechanisms underlying the enhancing effect of sodium cyanide on glutamate release using pharmacological approaches combined with other techniques. The results showed that sodium cyanide significantly increased glutamate release from synaptosomes of prefrontal cortex; the broad-spectrum free radical scavenger MnTBAP and melatonin completely abolished the effect of sodium cyanide on glutamate release; the H2O2-NMDA receptor pathway mediated one part, whereas the lipid peroxyl radicals-ATP synthase pathway mediated another part of the sodium cyanide-induced glutamate release; scavenging H2O2 and enhancing ATP synthase activity could completely abolish the sodium cyanide-induced glutamate release.
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Affiliation(s)
- Yi Dong
- State Key Laboratory of Medical Neurobiology, Shanghai Medical College and Institute of Brain Science, Fudan University, Shanghai, China
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Andrade F, Trujillo X, Sánchez-Pastor E, Montoya-Pérez R, Saavedra-Molina A, Ortiz-Mesina M, Huerta M. Glibenclamide increases post-fatigue tension in slow skeletal muscle fibers of the chicken. J Comp Physiol B 2010; 181:403-12. [PMID: 21079972 PMCID: PMC3058534 DOI: 10.1007/s00360-010-0527-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 10/08/2010] [Accepted: 10/25/2010] [Indexed: 01/18/2023]
Abstract
In contrast to fast-twitch skeletal muscle fibers of the chicken, slow-twitch fibers are fatigue-resistant. In fast fibers, the fatigue process has been related to K(ATP) channels. In the present study, we investigated the action of glibenclamide (an anti-diabetic sulphonylurea that acts on K(ATP) channels) on fatigued slow skeletal muscle, studying twitch and tetanus tension after inducing the muscle to fatigue by continuous electrical stimulation. Our results showed that glibenclamide (150 μM) increased post-fatigue twitch tension by about 25% with respect to the fatigued condition (P < 0.05). In addition, glibenclamide (150 μM) increased post-fatigue tetanic tension (83.61 ± 15.7% in peak tension, and 85.0 ± 19.0% in tension-time integral, P = 0.02, and 0.04, respectively; n = 3). Moreover, after exposing the muscle to a condition that inhibits mitochondrial ATP formation in order to activate K(ATP) channels with cyanide (10 mM), tension also diminished, but in the presence of glibenclamide the effect produced by cyanide was abolished. To determine a possible increase in intracellular calcium concentration, the effects of glibenclamide on caffeine-evoked contractures were explored. After muscle pre-incubation with glibenclamide (150 μM), tension of caffeine-evoked contractures increased (6.5 ± 1.5% in maximal tension, and 5.9 ± 3.8% in tension-time integral, P < 0.05). These results suggest a possible role of K(ATP) channels in the fatigue process, since glibenclamide increases twitch and tetanus tension in fatigued slow muscle of the chicken and during metabolic inhibition, possibly by increasing intracellular calcium.
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Affiliation(s)
- Felipa Andrade
- Instituto Tecnológico de Colima, Avenida Tecnológico No. 1, C.P. 28976, Villa de Álvarez, Colima, México
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Zhang SJ, Bruton JD, Katz A, Westerblad H. Limited oxygen diffusion accelerates fatigue development in mouse skeletal muscle. J Physiol 2006; 572:551-9. [PMID: 16455685 PMCID: PMC1779680 DOI: 10.1113/jphysiol.2005.104521] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 12/27/2005] [Accepted: 01/31/2006] [Indexed: 01/03/2023] Open
Abstract
Isolated whole skeletal muscles fatigue more rapidly than isolated single muscle fibres. We have now employed this difference to study mechanisms of skeletal muscle fatigue. Isolated whole soleus and extensor digitorum longus (EDL) muscles were fatigued by repeated tetanic stimulation while measuring force production. Neither application of 10 mm lactic acid nor increasing the [K(+)] of the bath solution from 5 to 10 mm had any significant effect on the rate of force decline during fatigue induced by repeated brief tetani. Soleus muscles fatigued slightly faster during continuous tetanic stimulation in 10 mm[K(+)]. Inhibition of mitochondrial respiration with cyanide resulted in a faster fatigue development in both soleus and EDL muscles. Single soleus muscle fibres were fatigued by repeated tetani while measuring force and myoplasmic free [Ca(2+)] ([Ca(2+)](i)). Under control conditions, the single fibres were substantially more fatigue resistant than the whole soleus muscles; tetanic force at the end of a series of 100 tetani was reduced by about 10% and 50%, respectively. However, in the presence of cyanide, fatigue developed at a similar rate in whole muscles and single fibres, and tetanic force at the end of fatiguing stimulation was reduced by approximately 80%. The force decrease in the presence of cyanide was associated with a approximately 50% decrease in tetanic [Ca(2+)](i), compared with an increase of approximately 20% without cyanide. In conclusion, lactic acid or [K(+)] has little impact on fatigue induced by repeated tetani, whereas hypoxia speeds up fatigue development and this is mainly due to an impaired Ca(2+) release from the sarcoplasmic reticulum.
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Affiliation(s)
- Shi-Jin Zhang
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Schmidt JJ, Stafford RG. Botulinum Neurotoxin Serotype F: Identification of Substrate Recognition Requirements and Development of Inhibitors with Low Nanomolar Affinity. Biochemistry 2005; 44:4067-73. [PMID: 15751983 DOI: 10.1021/bi0477642] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Botulinum neurotoxins (BoNTs A-G) are zinc metalloendoproteases that exhibit extraordinary specificities for proteins involved in neurotransmitter release. In view of the extreme toxicities of these molecules, their applications in human medicine, and potential for misuse, it is of considerable importance to elucidate the mechanisms underlying substrate recognition and to develop inhibitors, with the ultimate goal of obtaining anti-botulinum drugs. We synthesized peptides based on vesicle-associated membrane protein (VAMP) to investigate the substrate requirements of BoNT F, which cleaves VAMP between residues Q58 and K59. The minimum substrate was a peptide containing VAMP residues 32-65, which includes only one of the two VAMP structural motifs thought to be required for botulinum substrate recognition. BoNT F exhibited a strict requirement for residues D57 (P(2)), K59 (P(1)'), and L60 (P(2)'), but peptides containing substitutions for R56 (P(3)), Q58 (P(1)), and S61 (P(3)') were cleaved. Therefore, the P(2), P(1)', and P(2)' residues of VAMP are of paramount importance for BoNT F substrate recognition near the scissile bond. K(i) values of uncleavable analogues were similar to K(m) values of the substrate, suggesting that substrate discrimination occurs at the cleavage step, not at the initial binding step. We then synthesized inhibitors of BoNT F that incorporated d-cysteine in place of glutamine 58, exhibited K(i) values of 1-2 nM, and required binding groups on the N-terminal but not the C-terminal side of the zinc ligand. The latter characteristic distinguishes BoNT F from other zinc metalloendoproteases, including BoNTs A and B.
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Affiliation(s)
- James J Schmidt
- Toxinology Division, United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Maryland 21702, USA.
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Klawitter PF, Clanton TL. Tension-time index, fatigue, and energetics in isolated rat diaphragm: a new experimental model. J Appl Physiol (1985) 2004; 96:89-95. [PMID: 12972435 DOI: 10.1152/japplphysiol.00237.2003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The tension-time index (TTI) has been used to estimate mechanical load, energy utilization, blood flow, and susceptibility to fatigue in contracting muscle. The TTI can be defined, for a rhythmically contracting muscle, as the product of average force development divided by maximum tetanic force times duty cycle [contraction time / (contraction + relaxation time)]. In this study, the TTI concept was applied to isolated diaphragm via a method that allowed TTI to be clamped at a predetermined value. The hypothesis tested was that, at constant TTI, muscle energetics and the extent of fatigue would vary with stimulation frequency. Isolated diaphragm strips were stimulated at 25, 50, 75, or 100 Hz for 4 min, one per second. Duty cycle was continuously adjusted to maintain TTI at 0.07, which was near the highest TTI tolerated for 4 min, at 20-Hz stimulation. At the end of the fatigue run, muscles were either immediately frozen for determination ATP, creatine, and creatine phosphate concentrations (n = 6) or stimulated for evaluation of low- and high-frequency fatigue (n = 5). Results demonstrated no difference in the extent of fatigue or in the final ATP and creatine phosphate concentrations between groups. Large within-run increases in duty cycle were required at low stimulation frequencies, but only small increases were required at the highest frequencies. The results demonstrate that, at a constant TTI, similar fatigue properties predominate at all stimulation frequencies with no clear distinction between high- and low-frequency fatigue. The method of clamping TTI during fatigue may be useful for evaluating energetics and contractile function between treatment groups in isolated muscle when treatment influences baseline contractile characteristics.
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Affiliation(s)
- Paul F Klawitter
- Department of Emergency Medicine, Pulmonary and Critical Care Medicine, Dorothy M. Davis Heart & Lung Research Institute and Biophysics Graduate program, The Ohio State University, Columbus, OH 43210, USA
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Anne C, Turcaud S, Quancard J, Teffo F, Meudal H, Fournié-Zaluski MC, Roques BP. Development of Potent Inhibitors of Botulinum Neurotoxin Type B. J Med Chem 2003; 46:4648-56. [PMID: 14561084 DOI: 10.1021/jm0300680] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Botulinum neurotoxins are the most potent toxins known to date. They are zinc-metalloproteases able to cleave selectively an essential component of neurotransmitter exocytosis, causing the syndrome of botulism characterized by a flaccid paralysis. There is a great interest in designing antagonists of the action of these toxins. One way is to inhibit their catalytic activity. In this study, we report the design of such inhibitors directed toward BoNT/B. A study of the S(1) subsite specificity, using several beta-amino thiols, has shown that this subsite prefers a p-carboxybenzyl moiety. The specificity of the S(1)' and S(2)' subsites was studied using two libraries of pseudotripeptides containing the S(1) synthon derived from the best beta-amino thiol tested. Finally, a selection of various non natural amino acids for the recognition of the "prime" domain led to the most potent inhibitor of BoNT/B described to date with a K(i) value of 20 nM.
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Affiliation(s)
- Christine Anne
- Département de Pharmacochimie Moléculaire et Structurale, INSERM U266--CNRS FRE2463, UFR des Sciences Pharmaceutiques et Biologiques 4, Avenue de l'Observatoire--75270 Paris Cedex 06, France
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Hanson MA, Oost TK, Sukonpan C, Rich DH, Stevens RC. Structural Basis for BABIM Inhibition of Botulinum Neurotoxin Type B Protease. J Am Chem Soc 2000. [DOI: 10.1021/ja005533m] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Michael A. Hanson
- Department of Chemistry and Molecular Biology The Scripps Research Institute La Jolla, California 92037 Department of Chemistry and School of Pharmacy University of Wisconsin-Madison, 425 N. Charter Street Madison, Wisconsin 53706
| | - Thorsten K. Oost
- Department of Chemistry and Molecular Biology The Scripps Research Institute La Jolla, California 92037 Department of Chemistry and School of Pharmacy University of Wisconsin-Madison, 425 N. Charter Street Madison, Wisconsin 53706
| | - Chanokporn Sukonpan
- Department of Chemistry and Molecular Biology The Scripps Research Institute La Jolla, California 92037 Department of Chemistry and School of Pharmacy University of Wisconsin-Madison, 425 N. Charter Street Madison, Wisconsin 53706
| | - Daniel H. Rich
- Department of Chemistry and Molecular Biology The Scripps Research Institute La Jolla, California 92037 Department of Chemistry and School of Pharmacy University of Wisconsin-Madison, 425 N. Charter Street Madison, Wisconsin 53706
| | - Raymond C. Stevens
- Department of Chemistry and Molecular Biology The Scripps Research Institute La Jolla, California 92037 Department of Chemistry and School of Pharmacy University of Wisconsin-Madison, 425 N. Charter Street Madison, Wisconsin 53706
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