Identification of genes of Streptococcus sanguinis involved in its capacity to invade, persist and functionally affect human endothelial cells

• Grant number: 21/13074-9
• Support Opportunities: Regular Research Grants
• Start date: March 01, 2022
• End date: August 31, 2024
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Renata de Oliveira Mattos Graner
• Grantee: Renata de Oliveira Mattos Graner
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Associated researchers: Débora Campanella Bastos ; Thaís Larissa Araujo de Oliveira Silva

Abstract

Streptococcus sanguinis is a ubiquitous commensal species of the oral microbiome associated with cardiovascular infections by mechanisms as yet to be understood. Recently, we verified that S. sanguinis strains can invade and persist in human coronary arterial endothelial cells (HCAEC), an important function for bacterial persistence in cardiovascular tissues. There is evidence that this process requires the expression of genes involved in serum-mediated invasion of EC (pepO, cppA, srtA), as well as genes for bacterial persistence in the intracellular environment (nox, spxB, swan). The aim of this project is to investigate the roles of pepO, cppA, srtA, nox, spxB and swan in the capacity of S. sanguinis to invade and persist in human ECs, affecting viability and angiogenic functions of these cells. To this end, knockout mutant of these six genes obtained in previous projects (SKpepO, SKcppA, SKspxB) or to be constructed in this project (SKsrtA, SKnox, SKswan) will be compared with the parental strain SK36 (able to invade EC) regarding the rates of invasion in Human Umbilical Vein Endothelial Cell (HUVEC) and primary Human Coronary Artery Endothelial Cells (HCAEC). Mutants complemented with an episomal copy of the inactivated gene will be used as controls. HUVEC and HCAEC will be exposed to strains pre-treated or not with 20% human serum during increasing periods of time, and the numbers of intracellular viable bacteria assessed in antibiotic protection assays. In addition, the viability and the angiogenic potential of the HUVEC and/or HCAEC exposed to parent and mutant strains will be respectively determined in MTT and tube formation assays. Strains will be further analyzed in ex vivo assays of persistence in human blood and regarding binding to C3b of the complement system, as measured in serum-treated strains by flow cytometry. The findings of this project may reveal molecular mechanisms by which S. sanguinis invade and persist in EC, thus providing biological basis for developing therapies to control streptococcal cardiovascular infections. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

ALVES, LIVIA A.; NAVEED, HASSAN; FRANCO, EDUARDO M.; GARCIA, MAIRA TERRA; FREITAS, VICTOR A.; JUNQUEIRA, JULIANA C.; BASTOS, DEBORA C.; ARAUJO, THAIS L. S.; CHEN, TSUTE; MATTOS-GRANER, RENATA O.. PepO and CppA modulate Streptococcus sanguinis susceptibility to complement immunity and virulence. VIRULENCE, v. 14, n. 1, p. 16-pg., 2023-12-31. (17/19899-4, 19/20435-8, 18/12248-0, 18/02054-4, 18/13739-8, 21/13074-9)

MATTOS-GRANER, RENATA O.; KLEIN, MARLISE I.; ALVES, LIVIA ARAUJO. The complement system as a key modulator of the oral microbiome in health and disease. CRITICAL REVIEWS IN MICROBIOLOGY, v. N/A, p. 30-pg., 2023-01-05. (12/04222-5, 21/13074-9, 15/12940-3, 16/17216-4, 12/50966-6, 12/51832-3, 17/19899-4, 21/06801-1, 18/02054-4, 15/07237-1)