Correlating biological activity to thermo-structural analysis of the interaction of CTX with synthetic models of macrophage membranes

Sandra Coccuzzo Sampaio,Gabriel S Vignoli Muniz,M Teresa Lamy,Kerly Fernanda Mesquita Pasqualoto,Luciana De Araújo Pimenta,Marcos Roberto De Mattos Fontes,Evandro L Duarte

doi:10.1038/s41598-021-02552-0

Abstract

The important pharmacological actions of Crotoxin (CTX) on macrophages, the main toxin in the venom of Crotalus durissus terrificus, and its important participation in the control of different pathophysiological processes, have been demonstrated. The biological activities performed by macrophages are related to signaling mediated by receptors expressed on the membrane surface of these cells or opening and closing of ion channels, generation of membrane curvature and pore formation. In the present work, the interaction of the CTX complex with the cell membrane of macrophages is studied, both using biological cells and synthetic lipid membranes to monitor structural alterations induced by the protein. Here we show that CTX can penetrate THP-1 cells and induce pores only in anionic lipid model membranes, suggesting that a possible access pathway for CTX to the cell is via lipids with anionic polar heads. Considering that the selectivity of the lipid composition varies in different tissues and organs of the human body, the thermostructural studies presented here are extremely important to open new investigations on the biological activities of CTX in different biological systems.

Highlights

The important pharmacological actions of Crotoxin (CTX) on macrophages, the main toxin in the venom of Crotalus durissus terrificus, and its important participation in the control of different pathophysiological processes, have been demonstrated
Crotoxin (CTX) was the first protein purified from the rattlesnake, Crotalus durissus terrificus venom, which was isolated by Slotta and Fraenkel-Conrat[1]
In order to confirm the interaction of CTX with the membrane and its penetration into the cell, the fluorescence microscopy image assay with CTX fluorescein isothiocyanate (FITC)-labeled in THP-1 cells was performed

Summary

Introduction

The important pharmacological actions of Crotoxin (CTX) on macrophages, the main toxin in the venom of Crotalus durissus terrificus, and its important participation in the control of different pathophysiological processes, have been demonstrated. The anti-inflammatory action of CTX is associated with a decrease in the expression of adhesion molecules in cytokine secretion neutrophils and an increase in the secretion of resolving lipid mediators, such as lipoxin A4 and 15-Epi-LXA4, with important involvement of receptors for formyl peptide on leukocyte migration[19]. This toxin inhibits the phagocytosis capacity of both neutrophils[10] and macrophages[15]. In macrophages, dualism in the action of this toxin was evidenced, since it was observed both inhibition of some functional parameters, such as spreading and p hagocytosis[15], and stimulation of the respiratory burst (generation of oxygen peroxide), the generation of nitric oxide and the glucose and glutamine metabolism of these cells

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