Two-Component System VicRK Regulates Functions Associated with Establishment of Streptococcus sanguinis in Biofilms

Autor(es)

Moraes, Julianna J. ^[1] ; Stipp, Rafael N. ^[1] ; Harth-Chu, Erika N. ^[1] ; Camargo, Tarsila M. ^[1] ; Hoefling, Jose F. ^[1] ; Mattos-Graner, Renata O. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Piracicaba Dent Sch, Dept Oral Diag, Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Infection and Immunity; v. 82, n. 12, p. 4941-4951, DEC 2014.
• Citações Web of Science: 12

Resumo

Streptococcus sanguinis is a commensal pioneer colonizer of teeth and an opportunistic pathogen of infectious endocarditis. The establishment of S. sanguinis in host sites likely requires dynamic fitting of the cell wall in response to local stimuli. In this study, we investigated the two-component system (TCS) VicRK in S. sanguinis (VicRK(Ss)), which regulates genes of cell wall biogenesis, biofilm formation, and virulence in opportunistic pathogens. A vicK knockout mutant obtained from strain SK36 (SKvic) showed slight reductions in aerobic growth and resistance to oxidative stress but an impaired ability to form biofilms, a phenotype restored in the complemented mutant. The biofilm-defective phenotype was associated with reduced amounts of extracellular DNA during aerobic growth, with reduced production of H2O2, a metabolic product associated with DNA release, and with inhibitory capacity of S. sanguinis competitor species. No changes in autolysis or cell surface hydrophobicity were detected in SKvic. Reverse transcription-quantitative PCR (RT-qPCR), electrophoretic mobility shift assays (EMSA), and promoter sequence analyses revealed that VicR directly regulates genes encoding murein hydrolases (SSA\_0094, cwdP, and gbpB) and spxB, which encodes pyruvate oxidase for H2O2 production. Genes previously associated with spxB expression (spxR, ccpA, ackA, and tpK) were not transcriptionally affected in SKvic. RT-qPCR analyses of S. sanguinis biofilm cells further showed upregulation of VicRK targets (spxB, gbpB, and SSA\_0094) and other genes for biofilm formation (gtfP and comE) compared to expression in planktonic cells. This study provides evidence that VicRKSs regulates functions crucial for S. sanguinis establishment in biofilms and identifies novel VicRK targets potentially involved in hydrolytic activities of the cell wall required for these functions. (AU)

• Processo FAPESP: 08/58333-7 - Analise da funcao do sistema de dois componentes vicrk na biologia do streptococcus sanguinis
• Beneficiário: Julianna Joanna de Carvalho Moraes
• Linha de fomento: Bolsas no Brasil - Doutorado
• Processo FAPESP: 09/54182-7 - Analise da funcao do sistema de dois componentes vicrk na biologia de streptococcus sanguinis.
• Beneficiário: Renata de Oliveira Mattos Graner
• Linha de fomento: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/50547-0 - Characterization of GbpB/PcsB homologues in commensal species of oral streptococci
• Beneficiário: Erika Nikitza Shiauha Harth Chu
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado