Activation of J77A.1 Macrophages by Three Phospholipases A₂Isolated fromBothrops atroxSnake Venom

Abstract

In the present study, we investigated the in vitro effects of two basic myotoxic phospholipases A2 (PLA2), BaTX-I, a catalytically inactive Lys-49 variant, and BaTX-II, a catalytically active Asp-49, and of one acidic myotoxic PLA2, BaPLA2, a catalytically active Asp-49, isolated from Bothrops atrox snake venom, on the activation of J774A.1 macrophages. At noncytotoxic concentrations, the toxins did not affect the adhesion of the macrophages, nor their ability to detach. The data obtained showed that only BaTX-I stimulated complement receptor-mediated phagocytosis. However, BaTX-I, BaTX-II, and BaPLA2 induced the release of the superoxide anion by J774A.1 macrophages. Additionally, only BaTX-I raised the lysosomal volume of macrophages after 15 min of incubation. After 30 min, all the phospholipases increased this parameter, which was not observed within 60 min. Moreover, BaTX-I, BaTX-II, and BaPLA2 increased the number of lipid bodies on macrophages submitted to phagocytosis and not submitted to phagocytosis. However, BaTX-II and BaPLA2 induced the release of TNF-α by J774A.1 macrophages. Taken together, the data show that, despite differences in enzymatic activity, the three toxins induced inflammatory events and whether the enzyme is acidic or basic does not seem to contribute to these effects.

Superoxide induces protein oxidation in plasma and TNF-α elevation in macrophage culture: Insights into mechanisms of neurotoxicity following doxorubicin chemotherapy

“…Dox administration [32]. Macrophages are a principal source of TNF-α production in vivo [33–35], and microglial activation in brain following Dox-induced TNF-α elevation leads to the previously mentioned central nervous system toxicities [24, 33]. Here, we test our hypothesis that O 2 − •, administered as KO 2 , will lead to TNF-α elevation in macrophage culture similar to that observed following Dox administration [2].…”

Lemnitoxin, the major component of Micrurus lemniscatus coral snake venom, is a myotoxic and pro-inflammatory phospholipase A2

“…The release of histamine from mast cells has been proposed to be a mechanism of snake venom PLA2-induced local inflammation (Cirino et al, 1989;Teng, 1990, Landucci et al, 1998). Some group II snake venom PLA2 are able to recruit and activate leukocytes (Zuliani et al, 2005b, Moreira et al, 2011, Setúbal et al, 2013, Furtado et al, 2014, but there are only few reports on the action of group I snake venom PLA2. Naja m. mocambique PLA2 induced dose-and time-dependent cellular infiltration into the rat pleural cavity (Weichman et al, 1989).…”

Rastreamento em células in vitro de uma fosfolipase A2 da peçonha de Bothrops alternatus por meio de pontos quânticos de tamanhos mágicos

“…Other studies have also reported the ability of svPLA 2 to stimulate the production of pro-inflammatory proteins, including IL-12 and TNF-α [32,57,58]. There are studies that show that the increase of levels of TNF-α caused by bothropic PLA 2 is related to the elevation of the levels of reactive species of oxygen [59,60]. Other two PLA 2 s isolated from B. alternatus snake venom induce the production of superoxide in macrophages independently of their enzymatic activity through the activation of NADPH oxidase by the signaling pathway of protein kinase C (PKC) [34].…”