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Membrane cholesterol modulates the cytolytic mechanism of myotoxin II, a Lys49 phospholipase A 2 homologue from the venom of Bothrops asper
Author(s) -
Rangel José,
Quesada Orestes,
Gutiérrez José María,
Angulo Yamileth,
Lomonte Bruno
Publication year - 2011
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1758
Subject(s) - venom , myotoxin , snake venom , phospholipase a2 , cytolysis , chemistry , phospholipase , bothrops , biochemistry , biology , phospholipase a , enzyme , cytotoxicity , in vitro
Lys49 phospholipase A 2 (PLA 2 ) homologues present in crotalid snake venoms lack enzymatic activity, yet they induce skeletal muscle necrosis by a membrane permeabilizing mechanism whose details are only partially understood. The present study evaluated the effect of altering the membrane cholesterol content on the cytolytic activity of myotoxin II, a Lys49 PLA 2 isolated from the venom of Bothrops asper , using the myogenic cell line C2C12 as a model target. Cell membrane cholesterol depletion by methyl‐ β ‐cyclodextrin (M β CD) treatment enhanced the cytolytic action of myotoxin II, as well as of its bioactive C‐terminal synthetic peptide p 115‐129 . Conversely, cell membrane cholesterol enrichment by preformed cholesterol‐M β CD complexes reduced the cytolytic effect of myotoxin II. The toxic actions of myotoxin I, a catalytically active PLA 2 from the same venom, as well as of the cytolytic peptide melittin from bee venom, also increased in cholesterol‐depleted cells. Although physical and functional changes resulting from variations in membrane cholesterol are complex, these findings suggest that membrane fluidity could be a relevant parameter to explain the observed modulation of the cytolytic mechanism of myotoxin II, possibly influencing bilayer penetration. In concordance, the cytolytic effect of myotoxin II decreased in direct proportion to lower temperature, a physical factor that affects membrane fluidity. In conclusion, physicochemical properties that depend on membrane cholesterol content significantly influence the cytolytic mechanism of myotoxin II, reinforcing the concept that the primary site of action of Lys49 PLA 2 myotoxins is the plasma membrane. Copyright © 2011 John Wiley & Sons, Ltd.