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Bloch S, Hager-Mair FF, Andrukhov O, Schäffer C. Oral streptococci: modulators of health and disease. Front Cell Infect Microbiol 2024; 14:1357631. [PMID: 38456080 PMCID: PMC10917908 DOI: 10.3389/fcimb.2024.1357631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 02/05/2024] [Indexed: 03/09/2024] Open
Abstract
Streptococci are primary colonizers of the oral cavity where they are ubiquitously present and an integral part of the commensal oral biofilm microflora. The role oral streptococci play in the interaction with the host is ambivalent. On the one hand, they function as gatekeepers of homeostasis and are a prerequisite for the maintenance of oral health - they shape the oral microbiota, modulate the immune system to enable bacterial survival, and antagonize pathogenic species. On the other hand, also recognized pathogens, such as oral Streptococcus mutans and Streptococcus sobrinus, which trigger the onset of dental caries belong to the genus Streptococcus. In the context of periodontitis, oral streptococci as excellent initial biofilm formers have an accessory function, enabling late biofilm colonizers to inhabit gingival pockets and cause disease. The pathogenic potential of oral streptococci fully unfolds when their dissemination into the bloodstream occurs; streptococcal infection can cause extra-oral diseases, such as infective endocarditis and hemorrhagic stroke. In this review, the taxonomic diversity of oral streptococci, their role and prevalence in the oral cavity and their contribution to oral health and disease will be discussed, focusing on the virulence factors these species employ for interactions at the host interface.
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Affiliation(s)
- Susanne Bloch
- Competence Center for Periodontal Research, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
- Department of Chemistry, Institute of Biochemistry, NanoGlycobiology Research Group, Universität für Bodenkultur Wien, Vienna, Austria
| | - Fiona F. Hager-Mair
- Department of Chemistry, Institute of Biochemistry, NanoGlycobiology Research Group, Universität für Bodenkultur Wien, Vienna, Austria
| | - Oleh Andrukhov
- Competence Center for Periodontal Research, University Clinic of Dentistry, Medical University of Vienna, Vienna, Austria
| | - Christina Schäffer
- Department of Chemistry, Institute of Biochemistry, NanoGlycobiology Research Group, Universität für Bodenkultur Wien, Vienna, Austria
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2
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Franco EM, Alves LA, Naveed H, Freitas VAA, Bastos DC, Mattos-Graner RO. Amyloid Fibrils Produced by Streptococcus sanguinis Contribute to Biofilm Formation and Immune Evasion. Int J Mol Sci 2023; 24:15686. [PMID: 37958670 PMCID: PMC10647432 DOI: 10.3390/ijms242115686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 10/20/2023] [Indexed: 11/15/2023] Open
Abstract
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.
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Affiliation(s)
- Eduardo M. Franco
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
| | - Lívia A. Alves
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
- School of Dentistry, Cruzeiro do Sul University (UNICSUL), São Paulo 01506-000, SP, Brazil
| | - Hassan Naveed
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
| | - Victor A. A. Freitas
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
| | - Débora C. Bastos
- Department of Biosciences, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil;
- São Leopoldo Mandic Medical School, Campinas 13045-755, SP, Brazil
| | - Renata O. Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School, State University of Campinas, Piracicaba 13414-903, SP, Brazil; (E.M.F.); (L.A.A.); (H.N.); (V.A.A.F.)
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Neculae E, Gosav EM, Valasciuc E, Dima N, Floria M, Tanase DM. The Oral Microbiota in Valvular Heart Disease: Current Knowledge and Future Directions. LIFE (BASEL, SWITZERLAND) 2023; 13:life13010182. [PMID: 36676130 PMCID: PMC9862471 DOI: 10.3390/life13010182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 12/31/2022] [Accepted: 01/06/2023] [Indexed: 01/11/2023]
Abstract
Oral microbiota formation begins from birth, and everything from genetic components to the environment, alongside the host's behavior (such as diet, smoking, oral hygiene, and even physical activity), contributes to oral microbiota structure. Even though recent studies have focused on the gut microbiota's role in systemic diseases, the oral microbiome represents the second largest community of microorganisms, making it a new promising therapeutic target. Periodontitis and dental caries are considered the two main consequences of oral bacterial imbalance. Studies have shown that oral dysbiosis effects are not limited locally. Due to technological advancement, research identified oral bacterial species in heart valves. This evidence links oral dysbiosis with the development of valvular heart disease (VHD). This review focuses on describing the mechanism behind prolonged local inflammation and dysbiosis, that can induce bacteriemia by direct or immune-mediated mechanisms and finally VHD. Additionally, we highlight emerging therapies based on controlling oral dysbiosis, periodontal disease, and inflammation with immunological and systemic effects, that exert beneficial effects in VHD management.
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Affiliation(s)
- Ecaterina Neculae
- Department of Gastroenterology, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- Institute of Gastroenterology and Hepatology, “Sf. Spiridon” County Clinical Emergency Hospital Iasi, 700111 Iasi, Romania
| | - Evelina Maria Gosav
- Department of Internal Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- Internal Medicine Clinic, “St. Spiridon” County Clinical Emergency Hospital Iasi, 700111 Iasi, Romania
| | - Emilia Valasciuc
- Department of Internal Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- Internal Medicine Clinic, “St. Spiridon” County Clinical Emergency Hospital Iasi, 700111 Iasi, Romania
| | - Nicoleta Dima
- Department of Internal Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- Internal Medicine Clinic, “St. Spiridon” County Clinical Emergency Hospital Iasi, 700111 Iasi, Romania
| | - Mariana Floria
- Department of Internal Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- Internal Medicine Clinic, “St. Spiridon” County Clinical Emergency Hospital Iasi, 700111 Iasi, Romania
- Correspondence:
| | - Daniela Maria Tanase
- Department of Internal Medicine, “Grigore T. Popa” University of Medicine and Pharmacy, 700115 Iasi, Romania
- Internal Medicine Clinic, “St. Spiridon” County Clinical Emergency Hospital Iasi, 700111 Iasi, Romania
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4
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Zhang H, Xia M, Zhang B, Zhang Y, Chen H, Deng Y, Yang Y, Lei L, Hu T. Sucrose selectively regulates
Streptococcus mutans
polysaccharide by
GcrR. Environ Microbiol 2022; 24:1395-1410. [PMID: 35064734 DOI: 10.1111/1462-2920.15887] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 12/21/2021] [Indexed: 11/28/2022]
Affiliation(s)
- Hongyu Zhang
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Mengying Xia
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Bin Zhang
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Yue Zhang
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Hong Chen
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Yalan Deng
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Yingming Yang
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Lei Lei
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
| | - Tao Hu
- Department of Preventive Dentistry, West China School & Hospital of Stomatology Sichuan University, 14#, 3rd Section, Renmin South Road Chengdu Sichuan 610041 China
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The vicK gene of Streptococcus mutans mediates its cariogenicity via exopolysaccharides metabolism. Int J Oral Sci 2021; 13:45. [PMID: 34916484 PMCID: PMC8677823 DOI: 10.1038/s41368-021-00149-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 07/01/2021] [Accepted: 10/25/2021] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans (S. mutans) is generally regarded as a major contributor to dental caries because of its ability to synthesize extracellular polysaccharides (EPS) that aid in the formation of plaque biofilm. The VicRKX system of S. mutans plays an important role in biofilm formation. The aim of this study was to investigate the effects of vicK gene on specific characteristics of EPS in S. mutans biofilm. We constructed single-species biofilms formed by different mutants of vicK gene. Production and distribution of EPS were detected through atomic force microscopy, scanning electron microscopy and confocal laser scanning microscopy. Microcosmic structures of EPS were analyzed by gel permeation chromatography and gas chromatography-mass spectrometry. Cariogenicity of the vicK mutant was assessed in a specific pathogen-free rat model. Transcriptional levels of cariogenicity-associated genes were confirmed by quantitative real-time polymerase chain reaction. The results showed that deletion of vicK gene suppressed biofilm formation as well as EPS production, and EPS were synthesized mostly around the cells. Molecular weight and monosaccharide components underwent evident alterations. Biofilms formed in vivo were sparse and contributed a decreased degree of caries. Moreover, expressional levels of genes related to EPS synthesis were down-regulated, except for gtfB. Our report demonstrates that vicK gene enhances biofilm formation and subsequent caries development. And this may due to its regulations on EPS metabolism, like synthesis or microcosmic features of EPS. This study suggests that vicK gene and EPS can be considered as promising targets to modulate dental caries.
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Fernandes Forte CP, Oliveira FAF, Lopes CDB, Alves APNN, Mota MRL, de Barros Silva PG, Montenegro RC, Campos Ribeiro Dos Santos ÂK, Lobo Filho JG, Sousa FB. Streptococcus mutans in atherosclerotic plaque: Molecular and immunohistochemical evaluations. Oral Dis 2021; 28:1705-1714. [PMID: 33825326 DOI: 10.1111/odi.13869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 03/10/2021] [Accepted: 03/30/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To verify the presence of Streptococcus mutans (S. mutans) in atherosclerotic plaque (AP) using techniques with different sensitivities, correlating with histological changes in plaque and immunoexpression of inflammatory markers. MATERIALS AND METHODS Thirteen AP samples were subjected to real-time polymerase chain reaction (qRT-PCR), histopathological analyses, histochemical analysis by Giemsa staining (GS), and immunohistochemical analysis for S. mutans, IL-1β, and TNF-α (streptavidin-biotin-peroxidase method). Ten necropsy samples of healthy vessels were used as controls. RESULTS All AP samples showed histopathological characteristics of severe atherosclerosis and were positive for S. mutans (100.0%) in qRT-PCR and immunohistochemical analyses. GS showed that Streptococcus sp. colonized the lipid-rich core regions and fibrous tissue, while the control group was negative for Streptococcus sp. IL-1β and TNF-α were expressed in 100% and 92.3% of the AP tested, respectively. The control samples were positive for S. mutans in qRT-PCR analysis, but negative for S. mutans, IL-1β, and TNF-α in immunohistochemical analyses. CONCLUSION The detection of S. mutans in AP and the visualization of Streptococcus sp. suggested a possible association between S. mutans and atherosclerosis. The results obtained from the control samples suggested the presence of DNA fragments or innocuous bacteria that were not associated with tissue alteration. However, future studies are necessary to provide more information.
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Affiliation(s)
| | | | - Camile de Barros Lopes
- Department of Human and Medical Genetics, School of Biological Sciences, Federal University of Para, Belém, Brazil
| | | | - Mário Rogério Lima Mota
- Department of Stomatology and Oral Pathology, School of Dentistry, Federal University of Ceará, Fortaleza, Brazil
| | | | - Raquel Carvalho Montenegro
- Department of Human Cytogenetics, School of Biological Sciences, Federal University of Para, Belém, Brazil
| | | | | | - Fabrício Bitu Sousa
- Department of Stomatology and Oral Pathology, School of Dentistry, Federal University of Ceará, Fortaleza, Brazil
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7
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Wang S, Long L, Yang X, Qiu Y, Tao T, Peng X, Li Y, Han A, Senadheera DB, Downey JS, Goodman SD, Zhou X, Cvitkovitch DG. Dissecting the Role of VicK Phosphatase in Aggregation and Biofilm Formation of Streptococcus mutans. J Dent Res 2021; 100:631-638. [PMID: 33530836 DOI: 10.1177/0022034520979798] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
VicRK (WalRK or YycFG) is a conserved 2-component regulatory system (TCS) that regulates cell division, cell wall biosynthesis, and homeostasis in low-GC Gram-positive bacteria. VicRK is also associated with biofilm formation of Streptococcus mutans on the tooth surface as it directly regulates the extracellular polysaccharide (EPS) synthesis. Of the 2 components, VicK possesses both autokinase and phosphatase activities, which regulate the phosphorylation and dephosphorylation of the regulator VicR in response to environmental cues. However, the dual mechanism of VicK as the autokinase/phosphatase in regulating S. mutans' responses is not well elucidated. Previously, it has been shown that the phosphatase activity depends on the PAS domain and residues in the DHp domain of VicK in S. mutans. Specifically, mutating proline at 222 in the PAS domain inhibits VicK phosphatase activity. We generated a VicKP222A mutant to determine the level of VicR-P in the cytoplasm by Phos-tag sodium dodecyl sulfate polyacrylamide gel electrophoresis. We show that in VicKP222A phosphatase, attenuation increased phosphorylated VicR (VicR-P) that downregulated glucosyltransferases, gtfBC, thereby reducing the synthesis of water-insoluble polysaccharides (WIS-EPS) in the biofilm. In addition, VicKP222A presented as long-rod cells, reduced growth, and displayed asymmetrical division. A major adhesin of S. mutans, SpaP was downregulated in VicKP222A, making it unable to agglutinate in saliva. In summary, we have confirmed that VicK phosphatase activity is critical to maintain optimal phosphorylation status of VicR in S. mutans, which is important for cell growth, cell division, EPS synthesis, and bacterial agglutination in saliva. Hence, VicK phosphatase activity may represent a promising target to modulate S. mutans' pathogenicity.
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Affiliation(s)
- S Wang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - L Long
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X Yang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Qiu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - T Tao
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X Peng
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Li
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - A Han
- State Key Laboratory for Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen University Xiang'an Campus, Xiamen, Fujian, China
| | - D B Senadheera
- School of Dental Medicine, Stony Brook University, Stony Brook, NY, USA
| | - J S Downey
- Division of Biomedical Sciences, Herman Ostrow School of Dentistry of University of Southern California, Los Angeles, CA, USA
| | - S D Goodman
- Center for Microbial Pathogenesis, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - X Zhou
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - D G Cvitkovitch
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
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Alves LA, Ganguly T, Harth-Chú ÉN, Kajfasz J, Lemos JA, Abranches J, Mattos-Graner RO. PepO is a target of the two-component systems VicRK and CovR required for systemic virulence of Streptococcus mutans. Virulence 2020; 11:521-536. [PMID: 32427040 PMCID: PMC7239026 DOI: 10.1080/21505594.2020.1767377] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 03/10/2020] [Accepted: 03/29/2020] [Indexed: 12/14/2022] Open
Abstract
Streptococcus mutans, a cariogenic species, is often associated with cardiovascular infections. Systemic virulence of specific S. mutans serotypes has been associated with the expression of the collagen- and laminin-binding protein Cnm, which is transcriptionally regulated by VicRK and CovR. In this study, we characterized a VicRK- and CovR-regulated gene, pepO, coding for a conserved endopeptidase. Transcriptional and protein analyses revealed that pepO is highly expressed in S. mutans strains resistant to complement immunity (blood isolates) compared to oral isolates. Gel mobility assay, transcriptional, and Western blot analyses revealed that pepO is repressed by VicR and induced by CovR. Deletion of pepO in the Cnm+ strain OMZ175 (OMZpepO) or in the Cnm- UA159 (UApepO) led to an increased susceptibility to C3b deposition, and to low binding to complement proteins C1q and C4BP. Additionally, pepO mutants showed diminished ex vivo survival in human blood and impaired capacity to kill G. mellonella larvae. Inactivation of cnm in OMZ175 (OMZcnm) resulted in increased resistance to C3b deposition and unaltered blood survival, although both pepO and cnm mutants displayed attenuated virulence in G. mellonella. Unlike OMZcnm, OMZpepO could invade HCAEC endothelial cells. Supporting these phenotypes, recombinant proteins rPepO and rCnmA showed specific profiles of binding to C1q, C4BP, and to other plasma (plasminogen, fibronectin) and extracellular matrix proteins (type I collagen, laminin). Therefore this study identifies a novel VicRK/CovR-target required for immune evasion and host persistence, pepO, expanding the roles of VicRK and CovR in regulating S. mutans virulence.
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Affiliation(s)
- Lívia A. Alves
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
| | - Tridib Ganguly
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Érika N. Harth-Chú
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
| | - Jessica Kajfasz
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - José A. Lemos
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Jacqueline Abranches
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL, USA
| | - Renata O. Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School – State University of Campinas, Piracicaba, SP, Brazil
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9
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Alves LA, de Carli TR, Harth-Chu EN, Mariano FS, Höfling JF, Stipp RN, Mattos-Graner RO. Oral streptococci show diversity in resistance to complement immunity. J Med Microbiol 2019; 68:600-608. [PMID: 30843785 DOI: 10.1099/jmm.0.000955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Mechanisms underlying systemic infections by oral species of Mitis (Streptococcus mitis, Streptococcus oralis) and Sanguinis (Streptococcus gordonii, Streptococcus sanguinis) commensal streptococci are poorly understood. This study investigates profiles of susceptibility to complement-mediated host immunity in representative strains of these four species, which were isolated from oral sites or from the bloodstream. METHODOLOGY Deposition of complement opsonins (C3b/iC3b), and surface binding to C-reactive protein (CRP) and to IgG antibodies were quantified by flow cytometry in 34 strains treated with human serum (HS), and compared to rates of opsonophagocytosis by human PMN mediated by complement (CR1/3) and/or IgG Fc (FcγRII/III) receptors. RESULTS S. sanguinis strains showed reduced susceptibility to complement opsonization and low binding to CRP and to IgG compared to other species. Surface levels of C3b/iC3b in S. sanguinis strains were 4.5- and 7.8-fold lower than that observed in S. gordonii and Mitis strains, respectively. Diversity in C3b/iC3b deposition was evident among Mitis species, in which C3b/iC3b deposition was significantly associated with CR/FcγR-dependent opsonophagocytosis by PMN (P<0.05). Importantly, S. gordonii and Mitis group strains isolated from systemic infections showed resistance to complement opsonization when compared to oral isolates of the respective species (P<0.05). CONCLUSIONS This study establishes species-specific profiles of susceptibility to complement immunity in Mitis and Sanguinis streptococci, and indicates that strains associated with systemic infections have increased capacity to evade complement immunity. These findings highlight the need for studies identifying molecular functions involved in complement evasion in oral streptococci.
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Affiliation(s)
- Lívia A Alves
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Thaís R de Carli
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Erika N Harth-Chu
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Flávia S Mariano
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - José F Höfling
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Rafael N Stipp
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Renata O Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
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10
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Negrini TDC, Koo H, Arthur RA. Candida–Bacterial Biofilms and Host–Microbe Interactions in Oral Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1197:119-141. [DOI: 10.1007/978-3-030-28524-1_10] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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11
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CovR and VicRKX Regulate Transcription of the Collagen Binding Protein Cnm of Streptococcus mutans. J Bacteriol 2018; 200:JB.00141-18. [PMID: 30201780 DOI: 10.1128/jb.00141-18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Accepted: 09/04/2018] [Indexed: 11/20/2022] Open
Abstract
Cnm is a surface-associated protein present in a subset of Streptococcus mutans strains that mediates binding to extracellular matrices, intracellular invasion, and virulence. Here, we showed that cnm transcription is controlled by the global regulators CovR and VicRKX. In silico analysis identified multiple putative CovR- and VicR-binding motifs in the regulatory region of cnm as well as in the downstream gene pgfS, which is associated with the posttranslational modification of Cnm. Electrophoretic mobility shift assays revealed that CovR and VicR specifically and independently bind to the cnm and pgfS promoter regions. Quantitative real-time PCR and Western blot analyses of ΔcovR and ΔvicK strains as well as of a strain overexpressing vicRKX revealed that CovR functions as a positive regulator of cnm, whereas VicRKX acts as a negative regulator. In agreement with the role of VicRKX as a repressor, the ΔvicK strain showed enhanced binding to collagen and laminin and higher intracellular invasion rates. Overexpression of vicRKX was associated with decreased rates of intracellular invasion but did not affect collagen or lamin binding activities, suggesting that this system controls additional genes involved in binding to these extracellular matrix proteins. As expected, based on the role of CovR in cnm regulation, the ΔcovR strain showed decreased intracellular invasion rates, but, unexpectedly collagen and laminin binding activities were increased in this mutant strain. Collectively, the results presented here expand the repertoire of virulence-related genes regulated by CovR and VicRKX to include the core gene pgfS and the noncore gene cnm IMPORTANCE Streptococcus mutans is a major pathogen associated with dental caries and also implicated in systemic infections, in particular, infective endocarditis. The Cnm adhesin of S. mutans is an important virulence factor associated with systemic infections and caries severity. Despite its role in virulence, the regulatory mechanisms governing cnm expression are poorly understood. Here, we describe the identification of two independent regulatory systems controlling the transcription of cnm and the downstream pgfS-pgfM1-pgfE-pgfM2 operon. A better understanding of the mechanisms controlling expression of virulence factors like Cnm can facilitate the development of new strategies to treat bacterial infections.
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Alves LA, Harth-Chu EN, Palma TH, Stipp RN, Mariano FS, Höfling JF, Abranches J, Mattos-Graner RO. The two-component system VicRK regulates functions associated with Streptococcus mutans resistance to complement immunity. Mol Oral Microbiol 2017; 32:419-431. [PMID: 28382721 DOI: 10.1111/omi.12183] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/07/2017] [Accepted: 03/29/2017] [Indexed: 12/16/2022]
Abstract
Streptococcus mutans, a dental caries pathogen, can promote systemic infections upon reaching the bloodstream. The two-component system (TCS) VicRKSm of S. mutans regulates the synthesis of and interaction with sucrose-derived exopolysaccharides (EPS), processes associated with oral and systemic virulence. In this study, we investigated the mechanisms by which VicRKSm affects S. mutans susceptibility to blood-mediated immunity. Compared with parent strain UA159, the vicKSm isogenic mutant (UAvic) showed reduced susceptibility to deposition of C3b of complement, low binding to serum immunoglobulin G (IgG), and low frequency of C3b/IgG-mediated opsonophagocytosis by polymorphonuclear cells in a sucrose-independent way (P<.05). Reverse transcriptase quantitative polymerase chain reaction analysis comparing gene expression in UA159 and UAvic revealed that genes encoding putative peptidases of the complement (pepO and smu.399) were upregulated in UAvic in the presence of serum, although genes encoding murein hydrolases (SmaA and Smu.2146c) or metabolic/surface proteins involved in bacterial interactions with host components (enolase, GAPDH) were mostly affected in a serum-independent way. Among vicKSm -downstream genes (smaA, smu.2146c, lysM, atlA, pepO, smu.399), only pepO and smu.399 were associated with UAvic phenotypes; deletion of both genes in UA159 significantly enhanced levels of C3b deposition and opsonophagocytosis (P<.05). Moreover, consistent with the fibronectin-binding function of PepO orthologues, UAvic showed increased binding to fibronectin. Reduced susceptibility to opsonophagocytosis was insufficient to enhance ex vivo persistence of UAvic in blood, which was associated with growth defects of this mutant under limited nutrient conditions. Our findings revealed that S. mutans employs mechanisms of complement evasion through peptidases, which are controlled by VicRKSm.
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Affiliation(s)
- Livia A Alves
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Erika N Harth-Chu
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Thais H Palma
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Rafael N Stipp
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Flávia S Mariano
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - José F Höfling
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
| | - Jacqueline Abranches
- Department of Oral Biology, College of Dentistry - University of Florida, Gainesville, FL, USA
| | - Renata O Mattos-Graner
- Department of Oral Diagnosis, Piracicaba Dental School - State University of Campinas, Piracicaba, SP, Brazil
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CovR Regulates Streptococcus mutans Susceptibility To Complement Immunity and Survival in Blood. Infect Immun 2016; 84:3206-3219. [PMID: 27572331 DOI: 10.1128/iai.00406-16] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 08/20/2016] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans, a major pathogen of dental caries, may promote systemic infections after accessing the bloodstream from oral niches. In this study, we investigate pathways of complement immunity against S. mutans and show that the orphan regulator CovR (CovRSm) modulates susceptibility to complement opsonization and survival in blood. S. mutans blood isolates showed reduced susceptibility to C3b deposition compared to oral isolates. Reduced expression of covRSm in blood strains was associated with increased transcription of CovRSm-repressed genes required for S. mutans interactions with glucans (gbpC, gbpB, and epsC), sucrose-derived exopolysaccharides (EPS). Consistently, blood strains showed an increased capacity to bind glucan in vitro Deletion of covRSm in strain UA159 (UAcov) impaired C3b deposition and binding to serum IgG and C-reactive protein (CRP) as well as phagocytosis through C3b/iC3b receptors and killing by neutrophils. Opposite effects were observed in mutants of gbpC, epsC, or gtfBCD (required for glucan synthesis). C3b deposition on UA159 was abolished in C1q-depleted serum, implying that the classical pathway is essential for complement activation on S. mutans Growth in sucrose-containing medium impaired the binding of C3b and IgG to UA159, UAcov, and blood isolates but had absent or reduced effects on C3b deposition in gtfBCD, gbpC, and epsC mutants. UAcov further showed increased ex vivo survival in human blood in an EPS-dependent way. Consistently, reduced survival was observed for the gbpC and epsC mutants. Finally, UAcov showed an increased ability to cause bacteremia in a rat model. These results reveal that CovRSm modulates systemic virulence by regulating functions affecting S. mutans susceptibility to complement opsonization.
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Oliveira FAF, Forte CPF, Silva PGDB, Lopes CB, Montenegro RC, Santos ÂKCRD, Sobrinho CRMR, Mota MRL, Sousa FB, Alves APNN. Molecular Analysis of Oral Bacteria in Heart Valve of Patients With Cardiovascular Disease by Real-Time Polymerase Chain Reaction. Medicine (Baltimore) 2015; 94:e2067. [PMID: 26632711 PMCID: PMC5058980 DOI: 10.1097/md.0000000000002067] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/16/2015] [Accepted: 10/23/2015] [Indexed: 11/25/2022] Open
Abstract
Structural deficiencies and functional abnormalities of heart valves represent an important cause of cardiovascular morbidity and mortality, and a number of diseases, such as aortic stenosis, have been recently associated with infectious agents. This study aimed to analyze oral bacteria in dental plaque, saliva, and cardiac valves of patients with cardiovascular disease. Samples of supragingival plaque, subgingival plaque, saliva, and cardiac valve tissue were collected from 42 patients with heart valve disease. Molecular analysis of Streptococcus mutans, Prevotella intermedia, Porphyromonas gingivalis, and Treponema denticola was performed through real-time PCR. The micro-organism most frequently detected in heart valve samples was the S. mutans (89.3%), followed by P. intermedia (19.1%), P. gingivalis (4.2%), and T. denticola (2.1%). The mean decayed, missing, filled teeth (DMFT) was 26.4 ± 6.9 (mean ± SD), and according to the highest score of periodontal disease observed for each patient, periodontal pockets > 4 mm and dental calculus were detected in 43.4% and 34.7% of patients, respectively. In conclusion, oral bacteria, especially S. mutans, were found in the cardiac valve samples of patients with a high rate of caries and gingivitis/periodontitis.
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Affiliation(s)
- Francisco Artur Forte Oliveira
- From the Department of Stomatology and Oral Pathology, School of Dentistry, Federal University of Ceara, Fortaleza, Ceará (FAFO, CPF, PGBS, MRLM, FBS); Department of Oral Pathology, School of Dentistry, Federal University of Ceara, Fortaleza, Ceará (APNNA); Department of Clinical Medicine, School of Medicine, Federal University of Ceara, Fortaleza, Ceará (CRMRS); Laboratory of Human and Medical Genetics, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil (CBL, AKCRS); Human Cytogenetics Laboratory, Institute of Biological Sciences, Federal University of Pará, Belém, Pará, Brazil (RCM)
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CovR and VicRK regulate cell surface biogenesis genes required for biofilm formation in Streptococcus mutans. PLoS One 2013; 8:e58271. [PMID: 23554881 PMCID: PMC3595261 DOI: 10.1371/journal.pone.0058271] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 02/04/2013] [Indexed: 01/31/2023] Open
Abstract
The two-component system VicRK and the orphan regulator CovR of Streptococcus mutans co-regulate a group of virulence genes associated with the synthesis of and interaction with extracellular polysaccharides of the biofilm matrix. Knockout mutants of vicK and covR display abnormal cell division and morphology phenotypes, although the gene function defects involved are as yet unknown. Using transcriptomic comparisons between parent strain UA159 with vicK (UAvic) or covR (UAcov) deletion mutants together with electrophoretic motility shift assays (EMSA), we identified genes directly regulated by both VicR and CovR with putative functions in cell wall/surface biogenesis, including gbpB, wapE, smaA, SMU.2146c, and lysM. Deletion mutants of genes regulated by VicR and CovR (wapE, lysM, smaA), or regulated only by VicR (SMU.2146c) or CovR (epsC) promoted significant alterations in biofilm initiation, including increased fragility, defects in microcolony formation, and atypical cell morphology and/or chaining. Significant reductions in mureinolytic activity and/or increases in DNA release during growth were observed in knockout mutants of smaA, wapE, lysM, SMU.2146c and epsC, implying roles in cell wall biogenesis. WapE and lysM mutations also affected cell hydrophobicity and sensitivity to osmotic or oxidative stress. Finally, vicR, covR and VicRK/CovR-targets (gbpB, wapE, smaA, SMU.2146c, lysM, epsC) are up-regulated in UA159 during biofilm initiation, in a sucrose-dependent manner. These data support a model in which VicRK and CovR coordinate cell division and surface biogenesis with the extracellular synthesis of polysaccharides, a process apparently required for formation of structurally stable biofilms in the presence of sucrose.
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