Laboratório de Imunologia Celular Aplicada à Saúde, Fundação Oswaldo Cruz, FIOCRUZ Rondônia, Porto Velho, RO, Brazil.
Centro de Estudos de Biomoléculas Aplicadas à Saúde (CEBio), Fundação Oswaldo Cruz, FIOCRUZ Rondônia e Departamento de Medicina, Universidade Federal de Rondônia, UNIR, Porto Velho, RO, Brazil.
Int Immunopharmacol. 2022 Nov;112:109194. doi: 10.1016/j.intimp.2022.109194. Epub 2022 Aug 27.
Phospholipases A (PLAs) are proteins found in snake venoms with hemolytic, anticoagulant, myotoxic, edematogenic, bactericidal and inflammatory actions. In Bothrops jararacussu snake venom were isolated a Lys49-PLA (BthTX-I) and an Asp49-PLA (BthTX-II) with myotoxic and inflammatory actions. Both PLAs can activate the NLRP3 inflammasome, an intracytoplasmic platform that recognizes molecules released when tissue is damaged liberating IL-1β that contributes to the inflammatory response observed in envenoming. The dynamic of action of BthTX-I and BthTX-II in both thioglycollate (TG)-elicited macrophages and C2C12 myoblasts and the involvement of EP1 and EP2 receptors, and PGE in NLRP3 inflammasome activation were evaluated. Both toxins induced PGE liberation and inflammasome components (NLRP3, Caspase-1, ASC, IL-1β, and IL18), IL-6, P2X7, COX-1, COX-2, EP2 and EP4 gene expression in TG-elicited macrophages but not in C2C12 myoblasts. EP2 (PF04418948) and EP4 (GW627368X) inhibitors abolished this effect. Both PLAs also induced NLRP3 inflammasome protein expression that was abolished with the inhibitors used. Immunofluorescence and IL-1β assays confirmed the NLRP3 activation in TG-elicited macrophages with the participation of both EP2 and EP4 receptors confirming their involvement in this effect. All in all, BthTX-I and BthTX-II activate macrophages and induce the NLRP3 inflammasome complex activation with the participation of the PGE via COX pathway and EP2 and EP4, both PGE receptors, contributing to the local inflammatory effects observed in envenoming.
磷脂酶 A（PLAs）是在蛇毒液中发现的蛋白质，具有溶血、抗凝、肌毒性、水肿、杀菌和炎症作用。在 Bothrops jararacussu 蛇毒液中分离出一种赖氨酸 49-PLA（BthTX-I）和一种天冬氨酸 49-PLA（BthTX-II），具有肌毒性和炎症作用。两种 PLA 都可以激活 NLRP3 炎性体，这是一种识别细胞内当组织受损时释放的分子的细胞质内平台，释放白细胞介素-1β，有助于观察到的毒液中毒的炎症反应。在巯基乙酸盐（TG）诱导的巨噬细胞和 C2C12 成肌细胞中，评价了 BthTX-I 和 BthTX-II 的作用动态，以及 EP1 和 EP2 受体和 PGE 在 NLRP3 炎性体激活中的参与。两种毒素都诱导 PGE 释放和炎性体成分（NLRP3、Caspase-1、ASC、IL-1β 和 IL18）、IL-6、P2X7、COX-1、COX-2、EP2 和 EP4 基因表达在 TG 诱导的巨噬细胞中，但不在 C2C12 成肌细胞中。EP2（PF04418948）和 EP4（GW627368X）抑制剂消除了这种作用。两种 PLA 也诱导 NLRP3 炎性体蛋白表达，这种表达被抑制剂所消除。免疫荧光和 IL-1β 测定证实了 TG 诱导的巨噬细胞中 NLRP3 的激活，其中 EP2 和 EP4 受体参与了这种作用。总之，BthTX-I 和 BthTX-II 激活巨噬细胞并诱导 NLRP3 炎性体复合物的激活，通过 COX 途径和 EP2 和 EP4（均为 PGE 受体）参与，均有助于观察到的毒液中毒的局部炎症效应。
