Whole venom of Loxosceles similis activates caspases-3, -6, -7, and -9 in human primary skin fibroblasts.

Spiders of the Loxosceles genus represent a risk to human health due to the systemic and necrotic effects of their bites. The main symptoms of these bites vary from dermonecrosis, observed in the majority of cases, to occasional systemic hemolysis and coagulopathy. Although the systemic effects are well characterized, the mechanisms of cell death triggered by the venom of these spiders are poorly characterized. In this study, we investigated the cell death mechanisms induced by the whole venom of the spider Loxosceles similis in human skin fibroblasts. Our results show that the venom initiates an apoptotic process and a caspase cascade involving the initiator caspase-9 and the effector caspases-3, -6, and -7.