Amyloid Fibrils Produced by Streptococcus sanguinis Contribute to Biofilm Formation and Immune Evasion

Autor(es)

Franco, Eduardo M. ; Alves, Livia A. ; Naveed, Hassan ; Freitas, Victor A. A. ; Bastos, Debora C. ; Mattos-Graner, Renata O.

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES; v. 24, n. 21, p. 22-pg., 2023-11-01.

Resumo

Bacterial surface proteins assembled into amyloids contribute to biofilm formation and host immune evasion. Streptococcus sanguinis, a pioneer colonizer of teeth commonly involved in cardiovascular infections, expresses about thirty-three proteins anchored to the cell wall by sortase A. Here, we characterized the production of amyloid in S. sanguinis strains differing in biofilm and immune evasion phenotypes and investigated the role of sortase A in amyloidogenesis. Amyloid was identified in biofilms formed by nine strains, using Congo red (CR) staining and cross-polarized light microscopy. Additionally, EGCG, an amyloid inhibitor, impaired biofilm maturation in a strain-specific fashion. The amounts of amyloid-like components quantified in culture fluids of nine strains using thioflavin T and fluorimetry negatively correlated with bacterial binding to complement-activating proteins (SAP, C1q), C3b deposition and rates of opsonophagocytosis in PMNs, implying amyloid production in immune evasion. The deletion of the sortase A gene (srtA) in strain SK36 compromised amyloid production and sucrose-independent biofilm maturation. The srtA mutant further showed increased susceptibility to C3b deposition and altered interactions with PMNs as well as reduced persistence in human blood. These findings highlight the contribution of amyloids to biofilm formation and host immune evasion in S. sanguinis strains, further indicating the participation of sortase A substrates in amyloidogenesis. (AU)

• Processo FAPESP: 17/19899-4 - Identificação de fatores que modulam a susceptibilidade de Streptococcus sanguinis à imunidade mediada pelo sistema complemento
• Beneficiário: Lívia Araújo Alves
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 18/02054-4 - Identificação de fatores que modulam a susceptibilidade de Streptococcus sanguinis à imunidade mediada pelo sistema complemento
• Beneficiário: Renata de Oliveira Mattos Graner
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/12248-0 - Análise do papel de exopolissacarídeos e DNA extracelular no escape de Streptococcus sanguinis ao sistema complemento
• Beneficiário: Victor Aragão Abreu de Freitas
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 23/02087-8 - Isolamento e caracterização de Streptococcus spp. orais em amostras de pacientes com endocardite bacteriana
• Beneficiário: Lívia Araújo Alves
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 21/13074-9 - Identificação de genes de Streptococcus sanguinis envolvidos na capacidade desta espécie de invadir, persistir e alterar as funções de células endoteliais humanas
• Beneficiário: Renata de Oliveira Mattos Graner
• Modalidade de apoio: Auxílio à Pesquisa - Regular