Calcium imaging of muscle cells treated with snake myotoxins reveals toxin synergism and presence of acceptors

Snake myotoxins have a great impact on human health worldwide. Most of them adopt a phospholipase A2 fold and occur in two forms which often co-exist in the same venom: the Asp49 toxins hydrolyse phospholipids, whilst Lys49 toxins are enzymatically inactive. To gain insights into their mechanism of...

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Main Authors: Cintra Francischinelli, Mariana, Pizzo, Paola, Rodrigues Simioni, Lea, Ponce Soto, Luis Alberto, Rossetto, O., Lomonte, Bruno, Gutiérrez, José María, Pozzan, T., Montecucco, Cesare
Format: Artículo
Language: Inglés
Published: 2016
Subjects:
Online Access: http://link.springer.com/article/10.1007%2Fs00018-009-9053-2
http://hdl.handle.net/10669/29250
Summary: Snake myotoxins have a great impact on human health worldwide. Most of them adopt a phospholipase A2 fold and occur in two forms which often co-exist in the same venom: the Asp49 toxins hydrolyse phospholipids, whilst Lys49 toxins are enzymatically inactive. To gain insights into their mechanism of action, muscle cells were exposed to Bothrops myotoxins, and cytosolic Ca2+ and cytotoxicity were measured. In both myoblasts and myotubes, the myotoxins induced a rapid and transient rise in cytosolic [Ca2+], derived from intracellular stores, followed, only in myotubes, by a large Ca2+ influx and extensive cell death. Myoblast viability was unaffected. Notably, in myotubes Asp49 and Lys49 myotoxins acted synergistically to increase the plasma membrane Ca2+ permeability, inducing cell death. Therefore, these myotoxins may bind to acceptor(s) coupled to intracellular Ca2+ mobilization in both myoblasts and myotubes. However, in myotubes only, the toxins alter plasma membrane permeability, leading to death.