Muscle tissue damage is one of the local effects described in bothropic envenomations. Bothropstoxin-I (BthTX-I), from B. jararacussu venom, is a K49-phospholipase A2 that induces a massive muscle tissue injury, and, consequently, local inflammatory reaction. The NLRP3 inflammasome is a sensor that triggers inflammation by activating caspase 1 and releasing IL-1b and/or inducing pyroptotic cell death in response to tissue damage. We, therefore, aimed to address activation of NLRP3 inflammasome by BthTX-I-associated injury and the mechanism involved in this process. Intramuscular injection of BthTX-I results in infiltration of neutrophils and macrophages in gastrocnemius muscle, which is reduced in NLRP3- and Caspase-1-deficient mice. The in vitro IL-1β production induced by BthTX-I- inperitoneal macrophages requires caspase 1/11, ASC and NLRP3 and is dependent of ATP-induced K+ efflux and P2X7R. BthTX-I induces a dramatic release of ATP from C2C12 myotubes, therefore representing the major mechanism for P2X7R-dependent inflammasome activation in macrophages. A similar result was obtained when human monocyte-derived macrophages were treated with BthTX-I. These findings demonstrated the inflammatory effect of BthTX-I on muscle tissue, pointing out a role for the ATP released by damaged cells for the NLRP3 activation on macrophages, contributing to the understanding of the microenvironment of the tissue damage of the Bothrops envenomation.
Inflammatory effect of Bothropstoxin-I from the Bothrops jararacussu venom mediated by NLRP3 inflammasome involves ATP and P2X7 receptor
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Priscila Andrade Ranéia e Silva, Dhêmerson Souza de Lima, João Paulo Mesquita Luiz, Niels Olsen Saraiva Câmara, Jose Carlos Alves-Filho, Alessandra Pontillo, Karina Ramalho Bortoluci, Eliana Faquim de Lima Mauro; Inflammatory effect of Bothropstoxin-I from the Bothrops jararacussu venom mediated by NLRP3 inflammasome involves ATP and P2X7 receptor. Clin Sci (Lond) 2021; CS20201419. doi: https://doi.org/10.1042/CS20201419
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