Evaluation of inflammasome activation by the Natterin-like protein encoded by the loc795232 gene in zebrafish

• Grant number: 23/01659-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: October 01, 2023
• End date: February 28, 2025
• Field of knowledge: Biological Sciences - Genetics - Animal Genetics
• Principal Investigator: Carla Lima da Silva
• Grantee: Felipe Justiniano Pinto
• Host Institution: Instituto Butantan. Secretaria da Saúde (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 13/07467-1 - CeTICS - Center of Toxins, Immune-Response and Cell Signaling, AP.CEPID

Abstract

In the venom of Thalassophryne nattereri a new family of proteins named Natterin was identified, which was expanded by the inclusion of new members reaching a total of 331 species that present 859 natterin or natterin-like genes. The natterin-like genes do not have orthologs described in mammals, but in fish. Among the 109 species of fish that have one or more natterin-like genes, the zebrafish (Danio rerio) has 10 genes encoding 11 natterin-like proteins. Although the many biological functions for Natterin-like proteins remain uncharacterized to date, studies demonstrate their role as effector molecules of host innate immunity conferring protection against microbes. Our recent data show that the Natterin-like encoded by the gene loc795232 exerts the function of defense molecule against bacterial pathogens, causing the activation of the inflammasome complex, since we demonstrated that the larvae depleted by CRISPR/Cas9 of the natterin-like gene loc795232 were more susceptible to death by S. aureus and by S. typhimurium while surviving larvae showed altered patterns of locomotor activity in response to infection. The greater susceptibility to infection in natterin-like depleted larvae may be associated with deficient expression of mature caspase-a and caspase-b. Given its evolutionary conservation, its wide expression in tissues involved in immunity against infections and also its key role in development, we considered the hypothesis that members of the Natterina family, specifically the Natterina-like XP_017212453.1 encoded by gene loc795232, might be involved in the co-regulation of a pathway that affects the ability of inflammasome sensors to respond to an upstream signal or to relay that signal to its ASC adapter protein and consequently activate pro-caspase-1. In this project, our objective is to evaluate the specific function of two members of the Natterin family as effector molecules in the antibacterial defense for the zebrafish host, specifically evaluating their ability to interact with cytosolic sensors and critical signaling pathways for inflammasome activation.