Analysis of the roles of nox gene in Streptococcus sanguinis capacity to invade, persist and functionally affect human endothelial cells

• Grant number: 21/05804-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2021
• End date: March 31, 2023
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Renata de Oliveira Mattos Graner
• Grantee: Caio Simões de Paula
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Although Streptococcus sanguinis is one of the most common bacterial species of the oral microbiome associated with cardiovascular infections, its molecular mechanisms of virulence remain poorly understood. The gene nox, encoding for an NADH oxidase, was associated with S. sanguinis virulence in an in vivo model of infectious endocarditis by mechanisms as yet to be elucidated. In our preliminary studies, we observed that S. sanguinis strains significantly differ in nox transcription and in their capacity to invade and persist in primary human coronary artery endothelial cells (HCAEC), an important virulence function for cardiovascular infections. This project aims to investigate the role of nox in the invasion and persistence of S. sanguinis in human endothelial cells (EC), as well as in S. sanguinis effects on viability and angiogenic potential of EC. To that purpose, an isogenic mutant of nox (SKnox) will be constructed using the S. sanguinis strain SK36, known to infect and persist in EC. A SKnox mutant complemented with an episomal copy of nox (SKnox+) will be also obtained and used as control. The SKnox mutant will be then compared to parent SK36 and SKnox+ complemented strain in in vitro analyses of invasion and persistence in primary HCAEC and in Human umbilical vein endothelial cells (HUVECs). In addition, EC (HCAEC and/or HUVEC) previously challenged with the studied strains will be analyzed in MTT assays of cell viability and compared with respect to angiogenic potential in matrigel assays. The results of this project might reveal mechanisms applied by S. sanguinis to invade and persist in EC, opening new avenues to design therapies to control cardiovascular infections by streptococci. (AU)