title: The effect of brown spider venom on endothelial cell morphology and adhesive structures.
abstract: Spiders of the Loxosceles genus have been responsible for severe clinical cases of envenomation worldwide. Accidents involving brown spiders can cause dermonecrotic injury, hemorrhage, hemolysis, platelet aggregation and renal failure. Histological findings of animals treated by venom have shown subendothelial blebs, vacuoles and endothelial cell membrane degeneration of blood vessel walls, as well as fibrin and thrombus formation. The mechanisms by which the venom causes these disorders are poorly understood. In this work, with an endothelial cell line derived from rabbit aorta, we were able to demonstrate that venom binds to the cell surface and the extracellular matrix. Moreover, we observed that the venom also induced morphological alterations, such as cell retraction, homophilic disadhesion and an increasing in filopodia projections. We also demonstrated that toxins present in the venom disorganized focal adhesion points and actin microfilaments of endothelial cells. Nevertheless, endothelial cell viability showed no alterations compared to controls. Additionally, venom treatment changed the fibronectin matrix profile synthesized by these cells as well as cell adhesion to fibronectin. These results suggest that the deleterious effects of venom on blood vessel walls could be a consequence of the direct effect on the endothelial cell surface and adhesive structures involved in blood vessel stability. These effects indirectly lead to leukocyte and platelet activation, disseminated intravascular coagulation and an increase in vessel permeability.
authors.affiliation: Medical Clinic Discipline, Department of Medicine, UNIFESP, São Paulo, SP, Brazil.
authors.forename: Katia Sabrina
authors.initials: KS
authors.lastname: Paludo
authors.forename: Luiza Helena
authors.initials: LH
authors.lastname: Gremski
authors.forename: Silvio Sanches
authors.initials: SS
authors.lastname: Veiga
authors.forename: Olga Meiri
authors.initials: OM
authors.lastname: Chaim
authors.forename: Waldemiro
authors.initials: W
authors.lastname: Gremski
authors.forename: Dorly
authors.initials: D
authors.lastname: de Freitas Buchi
authors.forename: Helena Bonciani
authors.initials: HB
authors.lastname: Nader
authors.forename: Carl Peter
authors.initials: CP
authors.lastname: Dietrich
authors.forename: Célia Regina Cavichiolo
authors.initials: CR
authors.lastname: Franco
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects; D042783:Endothelial Cells / Q000166:cytology* / Q000187:drug effects* / Q000648:ultrastructure; D011817:Rabbits; D013111:Spider Venoms / Q000494:pharmacology*; D013112:Spiders
chemical_list: D013111:Spider Venoms