Cytotoxic and genotoxic effects on human keratinocytes triggered by sphingomyelinase D from Loxosceles venom

Author(s)

da Silva, Marcelo Santos ^[1] ; Lopes, Priscila Hess ^[2] ; Elias, Maria Carolina ^[1] ; Tambourgi, V, Denise

Affiliation

^[1] Butantan Inst, Lab Cell Cycle, Sao Paulo - Brazil

^[2] V, Butantan Inst, Immunochem Lab, Sao Paulo - Brazil

• Document type: Journal article
• Source: ARCHIVES OF TOXICOLOGY; v. 94, n. 10 JUN 2020.
• Web of Science Citations: 1

Abstract

The spiders of theLoxoscelesgenus (called brown or violin spiders) are of medical relevance in several countries due to the many human envenomation cases reported. The main component ofLoxoscelesvenom is the enzyme sphingomyelinase D (SMase D), which is responsible for the local and systemic effects induced by the whole venom. Here, we investigated the cytotoxic and genotoxic effects caused byLoxosceles laetavenom and SMase D on human keratinocytes to better understand the dermonecrosis development mechanism. Our findings indicate that whole venom, as well as SMase D, increases intracellular superoxide levels, leading to DNA damage. These effects appear to be dependent on the binding of SMase D to the cell surface, although the complete pathway triggered as a result of the binding still needs to be elucidated. Moreover, after SMase D treatment, we observed the presence of histone gamma H2AX, suggesting that the cells are undergoing DNA repair. Moreover, when ATR kinase was inhibited, the cell viability of human keratinocytes was decreased. Together, our findings strongly suggest thatL. laetavenom, as well as SMase D, increases intracellular superoxide levels, leading to DNA damage in human keratinocytes. Additionally, the induced DNA damage is repaired through the activation of an apparent ATR-mediated DNA-damage response. This knowledge may contribute to a better understanding of the behaviour of human keratinocytes during cutaneous loxoscelism, a condition that affects thousands of people around the world. (AU)

• FAPESP's process: 15/17053-5 - Study of inflamassomes activation, in human keratinocytes, by Loxosceles laeta spider venom and its sphingomyelinase D
• Grantee: Priscila Hess Lopes
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/07467-1 - CeTICS - Center of Toxins, Immune-Response and Cell Signaling
• Grantee: Hugo Aguirre Armelin
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 14/24170-5 - DNA replication dynamics in Trypanosoma cruzi: licensing and replication rate characterization
• Grantee: Marcelo Santos da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral