Inflammasome Activation Induced by a Snake Venom Lys49-Phospholipase A2 Homologue.

Charles Nunes Boeno,Sulamita Da Silva Setúbal,Weverson Luciano Pires,Juliana Pavan Zuliani,Jaína Rodrigues Evangelista,Andreimar Martins Soares,Mauro Valentino Paloschi,Jéssica Amaral Lopes

doi:10.3390/toxins12010022

Abstract

Background: Snake venom phospholipases A2 (PLA2s) have hemolytic, anticoagulant, myotoxic, oedematogenic, bactericidal, and inflammatory actions. BthTX-I, a Lys49-PLA2 isolated from Bothrops jararacussu venom, is an example of Lys49-PLA2 that presents such actions. NLRP3 is a cytosolic receptor from the NLR family responsible for inflammasome activation via caspase-1 activation and IL-1β liberation. The study of NLRs that recognize tissue damage and activate the inflammasome is relevant in envenomation. Methods: Male mice (18–20 g) received an intramuscular injection of BthTX-I or sterile saline. The serum was collected for creatine-kinase (CK), lactate dehydrogenase (LDH), and interleukin-1β (IL-1β) assays, and muscle was removed for inflammasome activation immunoblotting and qRT-PCR expression for nucleotide and oligomerization domain, leucine-rich repeat-containing protein family, pyrin-containing domain 3 receptor (NLRP3) inflammasome components. Results: BthTX-I-induced inflammation and myonecrosis, shown by intravital microscope, and LDH and CK release, respectively. Mouse treatment with A438079, a P2X7 receptor antagonist, did not modify these effects. BthTX-I induced inflammasome activation in muscle, but P2X7R participation in this effect was not observed. Conclusion: Together, the results showed for the first time that BthTX-I in gastrocnemius muscle induces inflammation and consequently, inflammasome activation via NLRP3 with caspase-1 activation and IL-1β liberation.

Highlights

Inflammasomes are multiprotein complexes present in the cytosol of immune cells
To assess the inflammatory and myotoxic reaction induced by BthTX-I in vivo, lactate dehydrogenase (LDH) and CK
Data obtained showed that BthTX-I induced a significant release of both mediators, LDH in plasma (Figure 1A) and CK (Figure 1B), 3 h after its injection in mouse gastrocnemius muscle compared with control

Summary

Introduction

Inflammasomes are multiprotein complexes present in the cytosol of immune cells. These complexes sense and respond to pathogen infection or tissue injury, and one of the most extensively studied inflammasomes is the NLRP3 (nucleotide and oligomerization domain, leucine-richToxins 2020, 12, 22; doi:10.3390/toxins12010022 www.mdpi.com/journal/toxinsToxins 2020, 12, 22 repeat-containing protein family, pyrin-containing domain 3 receptor) [1]. Inflammasomes are multiprotein complexes present in the cytosol of immune cells. These complexes sense and respond to pathogen infection or tissue injury, and one of the most extensively studied inflammasomes is the NLRP3 Pyroptosis precedes caspase-1 activation and is characterized by a rapid cell swelling and membrane rupture, leading to the release of intracellular contents. NLRP3 is a cytosolic receptor from the NLR family responsible for inflammasome activation via caspase-1 activation and IL-1β liberation. The serum was collected for creatine-kinase (CK), lactate dehydrogenase (LDH), and interleukin-1β (IL-1β) assays, and muscle was removed for inflammasome activation immunoblotting and qRT-PCR expression for nucleotide and oligomerization domain, leucine-rich repeat-containing protein family, pyrin-containing domain 3 receptor (NLRP3)

Methods

Results

Conclusion