Role of crotoxin in coagulation: novel insights into anticoagulant mechanisms and impairment of inflammation-induced coagulation.

Bruna Terada Gimenez,Elisa Maria De Sousa Russo,Aline De Sousa Bomfim,Marco Aurelio Sartim,Gabriel Neves Cezarette,Fabiani Gai Frantz,Suely Vilela Sampaio,Wuelton Marcelo Monteiro

doi:10.1590/1678-9199-jvatitd-2020-0076

Abstract

Background: Snake venom phospholipases A2 (svPLA2) are biologically active toxins, capable of triggering and modulating a wide range of biological functions. Among the svPLA2s, crotoxin (CTX) has been in the spotlight of bioprospecting research due to its role in modulating immune response and hemostasis. In the present study, novel anticoagulant mechanisms of CTX, and the modulation of inflammation-induced coagulation were investigated.Methods: CTX anticoagulant activity was evaluated using platelet poor plasma (PPP) and whole blood (WB), and also using isolated coagulation factors and complexes. The toxin modulation of procoagulant and pro-inflammatory effects was evaluated using the expression of tissue factor (TF) and cytokines in lipopolysaccharide (LPS)-treated peripheral blood mononuclear cells (PBMC) and in WB.Results: The results showed that CTX impaired clot formation in both PPP and WB, and was responsible for the inhibition of both intrinsic (TF/factor VIIa) and extrinsic (factor IXa/factor VIIIa) tenase complexes, but not for factor Xa and thrombin alone. In addition, the PLA2 mitigated the prothrombinase complex by modulating the coagulation phospholipid role in the complex. In regards to the inflammation-coagulation cross talk, the toxin was capable of reducing the production of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α, and was followed by decreased levels of TF and procoagulant activity from LPS-treated PBMC either isolated or in WB.Conclusion: The results obtained in the present study recognize the toxin as a novel medicinal candidate to be applied in inflammatory diseases with coagulation disorders.

Highlights

Snake venom phospholipases A2 are biologically active toxins, capable of triggering and modulating a wide range of biological functions
The results showed that CTX impaired clot formation in both platelet poor plasma (PPP) and whole blood (WB), and was responsible for the inhibition of both intrinsic (TF/factor VIIa) and extrinsic tenase complexes, but not for factor Xa and thrombin alone
Mounier et al [9] have shown that CB inhibited 80% of prothrombinase activity in the absence of phospholipid, and only 20% in its presence. These results show that the inhibitory effects of CTX on prothrombin activity involve the modulation of coagulant PLs, possibly being associated with the hydrolysis of these phospholipids or by the competition for phospholipid binding to coagulation factors, as observed in other Snake venom phospholipases A2 (svPLA2) [10]

Summary

Introduction

Snake venom phospholipases A2 (svPLA2) are biologically active toxins, capable of triggering and modulating a wide range of biological functions. Snake venom phospholipases A2 (svPLA2) are enzymes that when secreted catalyze the hydrolysis of phospholipids These enzymes are responsible for local and systemic effects such as myotoxicity, neuromuscular blockade, inflammation, and hemostasis alterations [1,2,3,4]. The mechanisms postulated for svPLA2 comprise i) the hydrolysis of procoagulant phospholipids; ii) the competition with coagulation factor for phospholipid binding, and/or iii) directly binding to coagulation factors preventing complex formation. Whether it is one or all of these, the overall response is the prevention of fibrin formation [9,10]

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Discussion

Conclusion