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Ramon C, Shay N, Malka A, Daniel E. Phlegmonous gastritis: Review of the pathophysiology. Am J Med Sci 2024; 367:274-277. [PMID: 38281622 DOI: 10.1016/j.amjms.2024.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/13/2023] [Accepted: 01/23/2024] [Indexed: 01/30/2024]
Abstract
Phlegmonous gastritis is a rare infection of the gastric wall. Clinical presentation of phlegmonous gastritis is generally non-specific and includes epigastric pain, nausea, vomiting and fever. The infection results from a transmural infection of the stomach. Several possible routes for phlegmonous gastritis have been proposed: a direct spread from the injured gastric mucosa site, a hematogenous spread to the stomach from a distant focus and lymphatic spread from a contiguous septic focus. The possibility that swallowing Streptococcus-containing secretion is also mentioned. We present a case of phlegmonous gastritis following a pharyngitis and discuss the routes of phlegmonous gastritis, the possible link to pharyngitis and review the diagnosis and treatment of this condition.
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Affiliation(s)
- Cohen Ramon
- Department of Internal Medicine B, Kaplan Medical Center, Rehovot, Israel.
| | - Nemet Shay
- Department of Clinical Immunology Allergy and AIDS, Kaplan Medical Center, Rehovot, Israel
| | - Attali Malka
- Department of Internal Medicine B, Kaplan Medical Center, Rehovot, Israel
| | - Elbirt Daniel
- Department of Clinical Immunology Allergy and AIDS, Kaplan Medical Center, Rehovot, Israel
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2
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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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3
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Keil J, Rafn GR, Turan IM, Aljohani MA, Sahebjam-Atabaki R, Sun XL. Sialidase Inhibitors with Different Mechanisms. J Med Chem 2022; 65:13574-13593. [PMID: 36252951 PMCID: PMC9620260 DOI: 10.1021/acs.jmedchem.2c01258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Indexed: 11/28/2022]
Abstract
Sialidases, or neuraminidases, are enzymes that catalyze the hydrolysis of sialic acid (Sia)-containing molecules, mostly removal of the terminal Sia (desialylation). By desialylation, sialidase can modulate the functionality of the target compound and is thus often involved in biological pathways. Inhibition of sialidases with inhibitors is an important approach for understanding sialidase function and the underlying mechanisms and could serve as a therapeutic approach as well. Transition-state analogues, such as anti-influenza drugs oseltamivir and zanamivir, are major sialidase inhibitors. In addition, difluoro-sialic acids were developed as mechanism-based sialidase inhibitors. Further, fluorinated quinone methide-based suicide substrates were reported. Sialidase product analogue inhibitors were also explored. Finally, natural products have shown competitive inhibiton against viral, bacterial, and human sialidases. This Perspective describes sialidase inhibitors with different mechanisms and their activities and future potential, which include transition-state analogue inhibitors, mechanism-based inhibitors, suicide substrate inhibitors, product analogue inhibitors, and natural product inhibitors.
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Affiliation(s)
- Joseph
M. Keil
- Department of Chemistry, Chemical and
Biomedical Engineering and Center for Gene Regulation in Health and
Disease (GRHD), Cleveland State University, Cleveland, Ohio 44115, United States
| | - Garrett R. Rafn
- Department of Chemistry, Chemical and
Biomedical Engineering and Center for Gene Regulation in Health and
Disease (GRHD), Cleveland State University, Cleveland, Ohio 44115, United States
| | - Isaac M. Turan
- Department of Chemistry, Chemical and
Biomedical Engineering and Center for Gene Regulation in Health and
Disease (GRHD), Cleveland State University, Cleveland, Ohio 44115, United States
| | - Majdi A. Aljohani
- Department of Chemistry, Chemical and
Biomedical Engineering and Center for Gene Regulation in Health and
Disease (GRHD), Cleveland State University, Cleveland, Ohio 44115, United States
| | - Reza Sahebjam-Atabaki
- Department of Chemistry, Chemical and
Biomedical Engineering and Center for Gene Regulation in Health and
Disease (GRHD), Cleveland State University, Cleveland, Ohio 44115, United States
| | - Xue-Long Sun
- Department of Chemistry, Chemical and
Biomedical Engineering and Center for Gene Regulation in Health and
Disease (GRHD), Cleveland State University, Cleveland, Ohio 44115, United States
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Lima BP, Davies JR, Wickström C, Johnstone KF, Hall JW, Svensater G, Herzberg MC. Streptococcus gordonii Poised for Glycan Feeding through a MUC5B-Discriminating, Lipoteichoic Acid-Mediated Outside-In Signaling Circuit. J Bacteriol 2022; 204:e0011822. [PMID: 35652671 PMCID: PMC9210975 DOI: 10.1128/jb.00118-22] [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: 03/30/2022] [Accepted: 05/09/2022] [Indexed: 11/20/2022] Open
Abstract
Many oral bacteria employ cell wall-anchored adhesins to bind to the salivary films coating the teeth and mucosal surfaces. Surface binding prevents clearance and facilitates catabolism of salivary film glycoproteins. We asked whether Streptococcus gordonii adhesin expression changes in response to surface salivary cues using a eukaryote-like, outside-in recognition and signaling circuit. To determine whether the cues were discriminated, S. gordonii was tested during cell adhesion and biofilm formation on a MUC5B-rich or lower-molecular-mass salivary fraction or an uncoated abiotic surface. Cells were recovered and analyzed for differences in gene expression and proteins in cell wall fractions. In salivary-free conditions, planktonic S. gordonii presented three prominent cell wall LPXTG-motif proteins, SGO_1487, SGO_0890, and MbpA (mucin-binding protein A; SGO_0707). During biofilm formation on MUC5B-coated surfaces, MbpA, a MUC5B-binding protein, and key genes in the tagatose and quorum-sensing pathways were strongly promoted. The response to MUC5B required the two-component system (TCS), streptococcal regulator of adhesins sensor and regulator (SraSR, SGO_1180/81), lipoteichoic acid (LTA), and the homologous paired adhesins, SspA and SspB (SspAB). LTA appears to link the outside signal (MUC5B) to intramembrane SraSR. Tagatose pathway gene expression may poise cells to metabolize MUC5B glycans and, with a quorum-sensing gene (luxS), may direct formation of a consortium to facilitate glycan cross-feeding by S. gordonii. We now show that a Gram-positive bacterium discriminates specific surface environmental cues using an outside-in signaling mechanism to apparently optimize colonization of saliva-coated surfaces. IMPORTANCE All organisms throughout the tree of life sense and respond to their surface environments. To discriminate among mucosal surface environmental cues, we report that Streptococcus gordonii recognizes a high-molecular-weight mucin glycoprotein, MUC5B, using the paired adhesins SspAB and lipoteichoic acid; the latter bridges the outside signal to an intramembrane two-component system to transcriptionally regulate a MUC5B-specific adhesin and genes that may facilitate glycan catabolism.
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Affiliation(s)
- Bruno P. Lima
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julia R. Davies
- Section for Oral Biology and Pathology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Claes Wickström
- Section for Oral Biology and Pathology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Karen F. Johnstone
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jeffrey W. Hall
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
| | - Gunnel Svensater
- Section for Oral Biology and Pathology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Mark C. Herzberg
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA
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Chahal G, Quintana-Hayashi MP, Gaytán MO, Benktander J, Padra M, King SJ, Linden SK. Streptococcus oralis Employs Multiple Mechanisms of Salivary Mucin Binding That Differ Between Strains. Front Cell Infect Microbiol 2022; 12:889711. [PMID: 35782137 PMCID: PMC9247193 DOI: 10.3389/fcimb.2022.889711] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 04/20/2022] [Indexed: 11/13/2022] Open
Abstract
Streptococcus oralis is an oral commensal and opportunistic pathogen that can enter the bloodstream and cause bacteremia and infective endocarditis. Here, we investigated the mechanisms of S. oralis binding to oral mucins using clinical isolates, isogenic mutants and glycoconjugates. S. oralis bound to both MUC5B and MUC7, with a higher level of binding to MUC7. Mass spectrometry identified 128 glycans on MUC5B, MUC7 and the salivary agglutinin (SAG). MUC7/SAG contained a higher relative abundance of Lewis type structures, including Lewis b/y, sialyl-Lewis a/x and α2,3-linked sialic acid, compared to MUC5B. S. oralis subsp. oralis binding to MUC5B and MUC7/SAG was inhibited by Lewis b and Lacto-N-tetraose glycoconjugates. In addition, S. oralis binding to MUC7/SAG was inhibited by sialyl Lewis x. Binding was not inhibited by Lacto-N-fucopentaose, H type 2 and Lewis x conjugates. These data suggest that three distinct carbohydrate binding specificities are involved in S. oralis subsp. oralis binding to oral mucins and that the mechanisms of binding MUC5B and MUC7 differ. Efficient binding of S. oralis subsp. oralis to MUC5B and MUC7 required the gene encoding sortase A, suggesting that the adhesin(s) are LPXTG-containing surface protein(s). Further investigation demonstrated that one of these adhesins is the sialic acid binding protein AsaA.
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Affiliation(s)
- Gurdeep Chahal
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | | | - Meztlli O. Gaytán
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children´s Hospital, Columbus, OH, United States
| | - John Benktander
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Medea Padra
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
| | - Samantha J. King
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children´s Hospital, Columbus, OH, United States
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, United States
- Infectious Diseases Institute, The Ohio State University, Columbus, OH, United States
- *Correspondence: Sara K. Linden, ; Samantha J. King,
| | - Sara K. Linden
- Department of Medical Biochemistry and Cell Biology, University of Gothenburg, Gothenburg, Sweden
- *Correspondence: Sara K. Linden, ; Samantha J. King,
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Jennings MP, Day CJ, Atack JM. How bacteria utilize sialic acid during interactions with the host: snip, snatch, dispatch, match and attach. MICROBIOLOGY (READING, ENGLAND) 2022; 168:001157. [PMID: 35316172 PMCID: PMC9558349 DOI: 10.1099/mic.0.001157] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/08/2022] [Indexed: 12/16/2022]
Abstract
N -glycolylneuraminic acid (Neu5Gc), and its precursor N-acetylneuraminic acid (Neu5Ac), commonly referred to as sialic acids, are two of the most common glycans found in mammals. Humans carry a mutation in the enzyme that converts Neu5Ac into Neu5Gc, and as such, expression of Neu5Ac can be thought of as a 'human specific' trait. Bacteria can utilize sialic acids as a carbon and energy source and have evolved multiple ways to take up sialic acids. In order to generate free sialic acid, many bacteria produce sialidases that cleave sialic acid residues from complex glycan structures. In addition, sialidases allow escape from innate immune mechanisms, and can synergize with other virulence factors such as toxins. Human-adapted pathogens have evolved a preference for Neu5Ac, with many bacterial adhesins, and major classes of toxin, specifically recognizing Neu5Ac containing glycans as receptors. The preference of human-adapted pathogens for Neu5Ac also occurs during biosynthesis of surface structures such as lipo-oligosaccharide (LOS), lipo-polysaccharide (LPS) and polysaccharide capsules, subverting the human host immune system by mimicking the host. This review aims to provide an update on the advances made in understanding the role of sialic acid in bacteria-host interactions made in the last 5-10 years, and put these findings into context by highlighting key historical discoveries. We provide a particular focus on 'molecular mimicry' and incorporation of sialic acid onto the bacterial outer-surface, and the role of sialic acid as a receptor for bacterial adhesins and toxins.
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Affiliation(s)
- Michael P. Jennings
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - Christopher J. Day
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
| | - John M. Atack
- Institute for Glycomics, Griffith University, Gold Coast, Queensland, Australia
- School of Environment and Science, Griffith University, Gold Coast, Queensland, Australia
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Complete Genome Sequence of Streptococcus oralis 34. Microbiol Resour Announc 2021; 10:e0076021. [PMID: 34472981 PMCID: PMC8411913 DOI: 10.1128/mra.00760-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Streptococcus oralis is an early colonizer and one of the most abundant species found in the human oral cavity. We report the complete genome sequence of S. oralis 34 (1,920,884 bp; GC content, 41.3%), commonly used in many oral microbiology studies exploring bacterial attachment and interaction(s) within mixed-species model systems.
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8
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Deacidification of Cranberry Juice Reduces Its Antibacterial Properties against Oral Streptococci but Preserves Barrier Function and Attenuates the Inflammatory Response of Oral Epithelial Cells. Foods 2021; 10:foods10071634. [PMID: 34359504 PMCID: PMC8305880 DOI: 10.3390/foods10071634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/28/2021] [Accepted: 07/10/2021] [Indexed: 02/07/2023] Open
Abstract
Cranberry (Vaccinium macrocarpon) may be a potent natural adjuvant for the prevention of oral diseases due to its anti-adherence, anti-cariogenic, and anti-inflammatory properties. However, the high titrable acidity of cranberry juice (CJ) has been reported to cause gastrointestinal discomfort, leading consumers to restrict their intake of this beverage. Electrodialysis with a bipolar membrane (EDBM) can reduce the organic acid content of CJ while retaining the flavonoids associated with potential health benefits. This study aimed to assess how the deacidification of CJ by EDBM impacts the antibacterial properties of the beverage against cariogenic (Streptococcus mutans, Streptococcus sobrinus) and commensal (Streptococcus gordonii, Streptococcus oralis, Streptococcus salivarius) streptococci, and how it affects oral epithelial barrier function and inflammatory response in an in vitro model. The removal of organic acids from CJ (deacidification rate ≥42%) reduced the bactericidal activity of the beverage against planktonic S. mutans and S. gordonii after a 15-min exposure, whereas only the viability of S. gordonii was significantly impacted by CJ deacidification rate when the bacteria were embedded in a biofilm. Moreover, conditioning saliva-coated hydroxyapatite with undiluted CJ samples significantly lowered the adherence of S. mutans, S. sobrinus, and S. oralis. With respect to epithelial barrier function, exposure to CJ deacidified at a rate of ≥19% maintained the integrity of a keratinocyte monolayer over the course of 24 h compared to raw CJ, as assessed by the determination of transepithelial electrical resistance (TER) and fluorescein isothiocyanate-conjugated dextran paracellular transport. These results can be in part attributed to the inability of the deacidified CJ to disrupt two tight junction proteins, zonula occludens-1 and occludin, following exposure, unlike raw CJ. Deacidification of CJ impacted the secretion of IL-6, but not of IL-8, by oral epithelial cells. In conclusion, deacidification of CJ appears to provide benefits with respect to the maintenance of oral health.
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Kono Y, Tamura M, Cueno ME, Tonogi M, Imai K. S-PRG Filler Eluate Induces Oxidative Stress in Oral Microorganism: Suppression of Growth and Pathogenicity, and Possible Clinical Application. Antibiotics (Basel) 2021; 10:antibiotics10070816. [PMID: 34356737 PMCID: PMC8300820 DOI: 10.3390/antibiotics10070816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/20/2022] Open
Abstract
Controlling the oral microbial flora is putatively thought to prevent not only oral diseases, but also systemic diseases caused by oral diseases. This study establishes the antibacterial effect of the novel bioactive substance “S-PRG filler” on oral bacteria. We examined the state of oxidative stress caused by the six types of ions released in eluate from the S-PRG filler in oral bacterial cells. Moreover, we investigated the effects of these ions on the growth and pathogenicity of Gram-positive and Gram-negative bacteria. We found that the released ions affected SOD amount and hydrogen peroxide in bacterial cells insinuating oxidative stress occurrence. In bacterial culture, growth inhibition was observed depending on the ion concentration in the medium. Additionally, released ions suppressed Streptococcus mutans adhesion to hydroxyapatite, S. oralis neuraminidase activity, and Porphyromonas gingivalis hemagglutination and gingipain activity in a concentration-dependent manner. From these results, it was suggested that the ions released from the S-PRG filler may suppress the growth and pathogenicity of the oral bacterial flora. This bioactive material is potentially useful to prevent the onset of diseases inside and outside of the oral cavity, which in turn may have possible applications for oral care and QOL improvement.
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Affiliation(s)
- Yu Kono
- Department of Oral and Maxillofacial Surgery I, Nihon University School of Dentistry, Tokyo 101-8310, Japan; (Y.K.); (M.T.)
| | - Muneaki Tamura
- Department of Microbiology, Nihon University School of Dentistry, Tokyo 101-8310, Japan; (M.E.C.); (K.I.)
- Correspondence: ; Tel.: +81-3219-8125
| | - Marni E. Cueno
- Department of Microbiology, Nihon University School of Dentistry, Tokyo 101-8310, Japan; (M.E.C.); (K.I.)
| | - Morio Tonogi
- Department of Oral and Maxillofacial Surgery I, Nihon University School of Dentistry, Tokyo 101-8310, Japan; (Y.K.); (M.T.)
| | - Kenichi Imai
- Department of Microbiology, Nihon University School of Dentistry, Tokyo 101-8310, Japan; (M.E.C.); (K.I.)
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Gaytán MO, Singh AK, Woodiga SA, Patel SA, An SS, Vera-Ponce de León A, McGrath S, Miller AR, Bush JM, van der Linden M, Magrini V, Wilson RK, Kitten T, King SJ. A novel sialic acid-binding adhesin present in multiple species contributes to the pathogenesis of Infective endocarditis. PLoS Pathog 2021; 17:e1009222. [PMID: 33465168 PMCID: PMC7846122 DOI: 10.1371/journal.ppat.1009222] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 01/29/2021] [Accepted: 11/30/2020] [Indexed: 02/07/2023] Open
Abstract
Bacterial binding to platelets is a key step in the development of infective endocarditis (IE). Sialic acid, a common terminal carbohydrate on host glycans, is the major receptor for streptococci on platelets. So far, all defined interactions between streptococci and sialic acid on platelets are mediated by serine-rich repeat proteins (SRRPs). However, we identified Streptococcus oralis subsp. oralis IE-isolates that bind sialic acid but lack SRRPs. In addition to binding sialic acid, some SRRP- isolates also bind the cryptic receptor β-1,4-linked galactose through a yet unknown mechanism. Using comparative genomics, we identified a novel sialic acid-binding adhesin, here named AsaA (associated with sialic acid adhesion A), present in IE-isolates lacking SRRPs. We demonstrated that S. oralis subsp. oralis AsaA is required for binding to platelets in a sialic acid-dependent manner. AsaA comprises a non-repeat region (NRR), consisting of a FIVAR/CBM and two Siglec-like and Unique domains, followed by 31 DUF1542 domains. When recombinantly expressed, Siglec-like and Unique domains competitively inhibited binding of S. oralis subsp. oralis and directly interacted with sialic acid on platelets. We further demonstrated that AsaA impacts the pathogenesis of S. oralis subsp. oralis in a rabbit model of IE. Additionally, we found AsaA orthologues in other IE-causing species and demonstrated that the NRR of AsaA from Gemella haemolysans blocked binding of S. oralis subsp. oralis, suggesting that AsaA contributes to the pathogenesis of multiple IE-causing species. Finally, our findings provide evidence that sialic acid is a key factor for bacterial-platelets interactions in a broader range of species than previously appreciated, highlighting its potential as a therapeutic target. Infective endocarditis (IE) is typically a bacterial infection of the heart valves that causes high mortality. Infective endocarditis can affect people with preexisting lesions on their heart valves (Subacute IE). These lesions contain platelets and other host factors to which bacteria can bind. Growth of bacteria and accumulation of host factors results in heart failure. Therefore, the ability of bacteria to bind platelets is key to the development of IE. Here, we identified a novel bacterial protein, AsaA, which helps bacteria bind to platelets and contributes to the development of disease. Although this virulence factor was characterized in Streptococcus oralis, a leading cause of IE, we demonstrated that AsaA is also present in several other IE-causing bacterial species and is likely relevant to their ability to cause disease. We showed that AsaA binds to sialic acid, a terminal sugar present on platelets, thereby demonstrating that sialic acid serves as a receptor for a wider range of IE-causing bacteria than previously appreciated, highlighting its potential as a therapeutic target.
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Affiliation(s)
- Meztlli O. Gaytán
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Anirudh K. Singh
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Shireen A. Woodiga
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Surina A. Patel
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Seon-Sook An
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Arturo Vera-Ponce de León
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Sean McGrath
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Anthony R. Miller
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Jocelyn M. Bush
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
| | - Mark van der Linden
- Institute of Medical Microbiology, German National Reference Center for Streptococci, University Hospital (RWTH), Aachen, Germany
| | - Vincent Magrini
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
| | - Richard K. Wilson
- Institute for Genomic Medicine, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
| | - Todd Kitten
- Philips Institute for Oral Health Research, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Samantha J. King
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, Ohio, United States of America
- Department of Pediatrics, The Ohio State University, Columbus, Ohio, United States of America
- * E-mail:
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11
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Smith NL, Nahrendorf W, Sutherland C, Mooney JP, Thompson J, Spence PJ, Cowan GJM. A Conserved TCRβ Signature Dominates a Highly Polyclonal T-Cell Expansion During the Acute Phase of a Murine Malaria Infection. Front Immunol 2020; 11:587756. [PMID: 33329568 PMCID: PMC7719809 DOI: 10.3389/fimmu.2020.587756] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 10/27/2020] [Indexed: 01/31/2023] Open
Abstract
CD4+ αβ T-cells are key mediators of the immune response to a first Plasmodium infection, undergoing extensive activation and splenic expansion during the acute phase of an infection. However, the clonality and clonal composition of this expansion has not previously been described. Using a comparative infection model, we sequenced the splenic CD4+ T-cell receptor repertoires generated over the time-course of a Plasmodium chabaudi infection. We show through repeat replicate experiments, single-cell RNA-seq, and analyses of independent RNA-seq data, that following a first infection - within a highly polyclonal expansion - T-effector repertoires are consistently dominated by TRBV3 gene usage. Clustering by sequence similarity, we find the same dominant clonal signature is expanded across replicates in the acute phase of an infection, revealing a conserved pathogen-specific T-cell response that is consistently a hallmark of a first infection, but not expanded upon re-challenge. Determining the host or parasite factors driving this conserved response may uncover novel immune targets for malaria therapeutic purposes.
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Affiliation(s)
- Natasha L. Smith
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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Chan JM, Gori A, Nobbs AH, Heyderman RS. Streptococcal Serine-Rich Repeat Proteins in Colonization and Disease. Front Microbiol 2020; 11:593356. [PMID: 33193266 PMCID: PMC7661464 DOI: 10.3389/fmicb.2020.593356] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 10/12/2020] [Indexed: 01/10/2023] Open
Abstract
Glycosylation of proteins, previously thought to be absent in prokaryotes, is increasingly recognized as important for both bacterial colonization and pathogenesis. For mucosal pathobionts, glycoproteins that function as cell wall-associated adhesins facilitate interactions with mucosal surfaces, permitting persistent adherence, invasion of deeper tissues and transition to disease. This is exemplified by Streptococcus pneumoniae and Streptococcus agalactiae, which can switch from being relatively harmless members of the mucosal tract microbiota to bona fide pathogens that cause life-threatening diseases. As part of their armamentarium of virulence factors, streptococci encode a family of large, glycosylated serine-rich repeat proteins (SRRPs) that facilitate binding to various tissue types and extracellular matrix proteins. This minireview focuses on the roles of S. pneumoniae and S. agalactiae SRRPs in persistent colonization and the transition to disease. The potential of utilizing SRRPs as vaccine targets will also be discussed.
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Affiliation(s)
- Jia Mun Chan
- NIHR Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Andrea Gori
- NIHR Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, United Kingdom
| | - Angela H. Nobbs
- Bristol Dental School, University of Bristol, Bristol, United Kingdom
| | - Robert S. Heyderman
- NIHR Mucosal Pathogens Research Unit, Division of Infection and Immunity, University College London, London, United Kingdom
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Stubbs HE, Bensing BA, Yamakawa I, Sharma P, Yu H, Chen X, Sullam PM, Iverson TM. Tandem sialoglycan-binding modules in a Streptococcus sanguinis serine-rich repeat adhesin create target dependent avidity effects. J Biol Chem 2020; 295:14737-14749. [PMID: 32820052 PMCID: PMC7586212 DOI: 10.1074/jbc.ra120.014177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/29/2020] [Indexed: 01/07/2023] Open
Abstract
Sialic acid-binding immunoglobulin-like lectins (Siglec)-like domains of streptococcal serine-rich repeat (SRR) adhesins recognize sialylated glycans on human salivary, platelet, and plasma glycoproteins via a YTRY sequence motif. The SRR adhesin from Streptococcus sanguinis strain SK1 has tandem sialoglycan-binding domains and has previously been shown to bind sialoglycans with high affinity. However, both domains contain substitutions within the canonical YTRY motif, making it unclear how they interact with host receptors. To identify how the S. sanguinis strain SK1 SRR adhesin affects interactions with sialylated glycans and glycoproteins, we determined high-resolution crystal structures of the binding domains alone and with purified trisaccharides. These structural studies determined that the ligands still bind at the noncanonical binding motif, but with fewer hydrogen-bonding interactions to the protein than is observed in structures of other Siglec-like adhesins. Complementary biochemical studies identified that each of the two binding domains has a different selectivity profile. Interestingly, the binding of SK1 to platelets and plasma glycoproteins identified that the interaction to some host targets is dominated by the contribution of one binding domain, whereas the binding to other host receptors is mediated by both binding domains. These results provide insight into outstanding questions concerning the roles of tandem domains in targeting host receptors and suggest mechanisms for how pathogens can adapt to the availability of a range of related but nonidentical host receptors. They further suggest that the definition of the YTRY motif should be changed to ϕTRX, a more rigorous description of this sialic acid-recognition motif given recent findings.
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Affiliation(s)
- Haley E. Stubbs
- Graduate Program in Chemical and Physical Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Barbara A. Bensing
- Department of Medicine, Veterans Affairs Medical Center, San Francisco, California, USA,Department of Medicine, University of California, San Francisco, California, USA
| | - Izumi Yamakawa
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | - Pankaj Sharma
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA
| | - Hai Yu
- Department of Chemistry, University of California, Davis, California, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, California, USA
| | - Paul M. Sullam
- Department of Medicine, Veterans Affairs Medical Center, San Francisco, California, USA
| | - T. M. Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee, USA,Department of Biochemistry, Vanderbilt University, Nashville, Tennessee, USA,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA,For correspondence: T. M. Iverson,
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14
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Lipničanová S, Chmelová D, Ondrejovič M, Frecer V, Miertuš S. Diversity of sialidases found in the human body - A review. Int J Biol Macromol 2020; 148:857-868. [PMID: 31945439 DOI: 10.1016/j.ijbiomac.2020.01.123] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 01/10/2020] [Accepted: 01/11/2020] [Indexed: 12/31/2022]
Abstract
Sialidases are enzymes essential for numerous organisms including humans. Hydrolytic sialidases (EC 3.2.1.18), trans-sialidases and anhydrosialidases (intramolecular trans-sialidases, EC 4.2.2.15) are glycoside hydrolase enzymes that cleave the glycosidic linkage and release sialic acid residues from sialyl substrates. The paper summarizes diverse sialidases present in the human body and their potential impact on development of antiviral compounds - inhibitors of viral neuraminidases. It includes a brief overview of catalytic mechanisms of action of sialidases and describes the origin of sialidases in the human body. This is followed by description of the structure and function of sialidase families with a special focus on the GH33 and GH34 families. Various effects of sialidases on human body are also briefly described. Modulation of sialidase activity may be considered a useful tool for effective treatment of various diseases. In some cases, it is desired to completely suppress the activity of sialidases by suitable inhibitors. Specific sialidase inhibitors are useful for the treatment of influenza, epilepsy, Alzheimer's disease, diabetes, different types of cancer, or heart defects. Challenges and future directions are shortly depicted in the final part of the paper.
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Affiliation(s)
- Sabina Lipničanová
- Department of Biotechnology, Faculty of Natural Sciences, University of Ss. Cyril and Methodius in Trnava, Nám. J. Herdu 2, SK-91701 Trnava, Slovakia
| | - Daniela Chmelová
- Department of Biotechnology, Faculty of Natural Sciences, University of Ss. Cyril and Methodius in Trnava, Nám. J. Herdu 2, SK-91701 Trnava, Slovakia.
| | - Miroslav Ondrejovič
- Department of Biotechnology, Faculty of Natural Sciences, University of Ss. Cyril and Methodius in Trnava, Nám. J. Herdu 2, SK-91701 Trnava, Slovakia.
| | - Vladimír Frecer
- Department of Physical Chemistry of Drugs, Faculty of Pharmacy, Comenius University in Bratislava, Odbojárov 10, SK-83232 Bratislava, Slovakia; ICARST n.o., Jamnického 19, SK-84101, Bratislava, Slovakia.
| | - Stanislav Miertuš
- Department of Biotechnology, Faculty of Natural Sciences, University of Ss. Cyril and Methodius in Trnava, Nám. J. Herdu 2, SK-91701 Trnava, Slovakia; ICARST n.o., Jamnického 19, SK-84101, Bratislava, Slovakia.
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15
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Streptococcus oralis subsp. dentisani Produces Monolateral Serine-Rich Repeat Protein Fibrils, One of Which Contributes to Saliva Binding via Sialic Acid. Infect Immun 2019; 87:IAI.00406-19. [PMID: 31308084 DOI: 10.1128/iai.00406-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022] Open
Abstract
Our studies reveal that the oral colonizer and cause of infective endocarditis Streptococcus oralis subsp. dentisani displays a striking monolateral distribution of surface fibrils. Furthermore, our data suggest that these fibrils impact the structure of adherent bacterial chains. Mutagenesis studies indicate that these fibrils are dependent on three serine-rich repeat proteins (SRRPs), here named fibril-associated protein A (FapA), FapB, and FapC, and that each SRRP forms a different fibril with a distinct distribution. SRRPs are a family of bacterial adhesins that have diverse roles in adhesion and that can bind to different receptors through modular nonrepeat region domains. Amino acid sequence and predicted structural similarity searches using the nonrepeat regions suggested that FapA may contribute to interspecies interactions, that FapA and FapB may contribute to intraspecies interactions, and that FapC may contribute to sialic acid binding. We demonstrate that a fapC mutant was significantly reduced in binding to saliva. We confirmed a role for FapC in sialic acid binding by demonstrating that the parental strain was significantly reduced in adhesion upon addition of a recombinantly expressed, sialic acid-specific, carbohydrate binding module, while the fapC mutant was not reduced. However, mutation of a residue previously shown to be essential for sialic acid binding did not decrease bacterial adhesion, leaving the precise mechanism of FapC-mediated adhesion to sialic acid to be defined. We also demonstrate that the presence of any one of the SRRPs is sufficient for efficient biofilm formation. Similar structures were observed on all infective endocarditis isolates examined, suggesting that this distribution is a conserved feature of this S. oralis subspecies.
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16
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Sulyanto RM, Thompson ZA, Beall CJ, Leys EJ, Griffen AL. The Predominant Oral Microbiota Is Acquired Early in an Organized Pattern. Sci Rep 2019; 9:10550. [PMID: 31332213 PMCID: PMC6646312 DOI: 10.1038/s41598-019-46923-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 06/14/2019] [Indexed: 12/31/2022] Open
Abstract
The human oral cavity is sterile prior to birth, and we have limited knowledge of how complex oral communities are assembled. To examine bacterial acquisition and community assembly over the first year of life, oral samples from a cohort of nine infants and their mothers were collected, and bacterial community composition was studied by 16S rRNA gene sequencing. Exogenous species including skin and environmental bacteria were present initially, but were quickly replaced by a small, shared microbial community of species common to all infants and adults. Subsequent ordered microbial succession and the formation of increasingly complex communities was observed. By one year of age oral microbial community composition converged to a profile that was remarkably similar among children. The introduction of new nutrient sources, but not tooth eruption, was associated with increasing complexity. Infants had fewer species than mothers, mostly accounted for by the lack of certain anaerobes, and showing that the acquisition and assembly of oral microbial communities continues past infancy. When relative abundance was considered, a shared set of species accounted for the majority of the microbial community at all ages, indicating that the dominant structure of the oral microbiome establishes early, and suggesting that it persists throughout life.
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Affiliation(s)
- Rosalyn M Sulyanto
- Boston Children's Hospital and Harvard School of Dental Medicine, 300 Longwood Avenue, Hunnewell 4, Boston, MA, 02115, USA
| | - Zachary A Thompson
- The Ohio State University, College of Dentistry, 4126 Postle Hall, 305 W. 12th Ave, Columbus, OH, 43210, USA
| | - Clifford J Beall
- The Ohio State University, College of Dentistry, 4126 Postle Hall, 305 W. 12th Ave, Columbus, OH, 43210, USA
| | - Eugene J Leys
- The Ohio State University, College of Dentistry, 4126 Postle Hall, 305 W. 12th Ave, Columbus, OH, 43210, USA
| | - Ann L Griffen
- The Ohio State University, College of Dentistry, 4126 Postle Hall, 305 W. 12th Ave, Columbus, OH, 43210, USA.
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17
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Robinson LS, Schwebke J, Lewis WG, Lewis AL. Identification and characterization of NanH2 and NanH3, enzymes responsible for sialidase activity in the vaginal bacterium Gardnerella vaginalis. J Biol Chem 2019; 294:5230-5245. [PMID: 30723162 DOI: 10.1074/jbc.ra118.006221] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/29/2019] [Indexed: 11/06/2022] Open
Abstract
Gardnerella vaginalis is abundant in bacterial vaginosis (BV), a condition associated with adverse reproductive health. Sialidase activity is a diagnostic feature of BV and is produced by a subset of G. vaginalis strains. Although its genetic basis has not been formally identified, sialidase activity is presumed to derive from the sialidase A gene, named here nanH1 In this study, BLAST searches predicted two additional G. vaginalis sialidases, NanH2 and NanH3. When expressed in Escherichia coli, NanH2 and NanH3 both displayed broad abilities to cleave sialic acids from α2-3- and α2-6-linked N- and O-linked sialoglycans, including relevant mucosal substrates. In contrast, recombinant NanH1 had limited activity against synthetic and mucosal substrates under the conditions tested. Recombinant NanH2 was much more effective than NanH3 in cleaving sialic acids bearing a 9-O-acetyl ester. Similarly, G. vaginalis strains encoding NanH2 cleaved and foraged significantly more Neu5,9Ac2 than strains encoding only NanH3. Among a collection of 34 G. vaginalis isolates, nanH2, nanH3, or both were present in all 15 sialidase-positive strains but absent from all 19 sialidase-negative isolates, including 16 strains that were nanH1-positive. We conclude that NanH2 and NanH3 are the primary sources of sialidase activity in G. vaginalis and that these two enzymes can account for the previously described substrate breadth cleaved by sialidases in human vaginal specimens of women with BV. Finally, PCRs of nanH2 or nanH3 from human vaginal specimens had 81% sensitivity and 78% specificity in distinguishing between Lactobacillus dominance and BV, as determined by Nugent scoring.
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Affiliation(s)
- Lloyd S Robinson
- From the Departments of Molecular Microbiology and.,Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110 and
| | - Jane Schwebke
- the Division of Infectious Diseases, University of Alabama, Birmingham, Alabama 35294
| | - Warren G Lewis
- From the Departments of Molecular Microbiology and.,Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110 and
| | - Amanda L Lewis
- From the Departments of Molecular Microbiology and .,Center for Women's Infectious Disease Research, Washington University School of Medicine, St. Louis, Missouri 63110 and.,Obstetrics and Gynecology and
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18
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Church B, Wall E, Webb JR, Cameron CE. Interaction of Treponema pallidum, the syphilis spirochete, with human platelets. PLoS One 2019; 14:e0210902. [PMID: 30657796 PMCID: PMC6338379 DOI: 10.1371/journal.pone.0210902] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/03/2019] [Indexed: 02/06/2023] Open
Abstract
Extracellular bacteria that spread via the vasculature employ invasive mechanisms that mirror those of metastatic tumor cells, including intravasation into the bloodstream and survival during hematogenous dissemination, arrestation despite blood flow, and extravasation into distant tissue sites. Several invasive bacteria have been shown to exploit normal platelet function during infection. Due to their inherent ability to interact with and influence other cell types, platelets play a critical role in alteration of endothelial barrier permeability, and their role in cancer metastasis has been well established. The highly invasive bacterium and causative agent of syphilis, Treponema pallidum subspecies pallidum, readily crosses the endothelial, blood-brain and placental barriers. However, the mechanisms underlying this unusual and important aspect of T. pallidum pathogenesis are incompletely understood. In this study we use darkfield microscopy in combination with flow cytometry to establish that T. pallidum interacts with platelets. We also investigate the dynamics of this interaction and show T. pallidum is able to activate platelets and preferentially interacts with activated platelets. Platelet-interacting treponemes consistently exhibit altered kinematic (movement) parameters compared to free treponemes, and T. pallidum-platelet interactions are reversible. This study provides insight into host cell interactions at play during T. pallidum infection and suggests that T. pallidum may exploit platelet function to aid in establishment of disseminated infection.
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Affiliation(s)
- Brigette Church
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Erika Wall
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - John R. Webb
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
- Trev and Joyce Deeley Research Centre, British Columbia Cancer Agency, Victoria, BC, Canada
| | - Caroline E. Cameron
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
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19
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The Role of Platelets in Antimicrobial Host Defense. Platelets 2019. [DOI: 10.1016/b978-0-12-813456-6.00029-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
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20
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Abranches J, Zeng L, Kajfasz JK, Palmer SR, Chakraborty B, Wen ZT, Richards VP, Brady LJ, Lemos JA. Biology of Oral Streptococci. Microbiol Spectr 2018; 6:10.1128/microbiolspec.GPP3-0042-2018. [PMID: 30338752 PMCID: PMC6287261 DOI: 10.1128/microbiolspec.gpp3-0042-2018] [Citation(s) in RCA: 246] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Indexed: 02/06/2023] Open
Abstract
Bacteria belonging to the genus Streptococcus are the first inhabitants of the oral cavity, which can be acquired right after birth and thus play an important role in the assembly of the oral microbiota. In this article, we discuss the different oral environments inhabited by streptococci and the species that occupy each niche. Special attention is given to the taxonomy of Streptococcus, because this genus is now divided into eight distinct groups, and oral species are found in six of them. Oral streptococci produce an arsenal of adhesive molecules that allow them to efficiently colonize different tissues in the mouth. Also, they have a remarkable ability to metabolize carbohydrates via fermentation, thereby generating acids as byproducts. Excessive acidification of the oral environment by aciduric species such as Streptococcus mutans is directly associated with the development of dental caries. However, less acid-tolerant species such as Streptococcus salivarius and Streptococcus gordonii produce large amounts of alkali, displaying an important role in the acid-base physiology of the oral cavity. Another important characteristic of certain oral streptococci is their ability to generate hydrogen peroxide that can inhibit the growth of S. mutans. Thus, oral streptococci can also be beneficial to the host by producing molecules that are inhibitory to pathogenic species. Lastly, commensal and pathogenic streptococci residing in the oral cavity can eventually gain access to the bloodstream and cause systemic infections such as infective endocarditis.
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Affiliation(s)
- J Abranches
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL
| | - L Zeng
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL
| | - J K Kajfasz
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL
| | - S R Palmer
- Division of Biosciences, College of Dentistry, Ohio State University, Columbus, OH
| | - B Chakraborty
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL
| | - Z T Wen
- Department of Comprehensive Dentistry and Biomaterials and Department of Microbiology, Immunology and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA
| | - V P Richards
- Department of Biological Sciences, Clemson University, Clemson, SC
| | - L J Brady
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL
| | - J A Lemos
- Department of Oral Biology, University of Florida College of Dentistry, Gainesville, FL
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Cross BW, Ruhl S. Glycan recognition at the saliva - oral microbiome interface. Cell Immunol 2018; 333:19-33. [PMID: 30274839 DOI: 10.1016/j.cellimm.2018.08.008] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 08/16/2018] [Accepted: 08/17/2018] [Indexed: 01/25/2023]
Abstract
The mouth is a first critical interface where most potentially harmful substances or pathogens contact the host environment. Adaptive and innate immune defense mechanisms are established there to inactivate or eliminate pathogenic microbes that traverse the oral environment on the way to their target organs and tissues. Protein and glycoprotein components of saliva play a particularly important role in modulating the oral microbiota and helping with the clearance of pathogens. It has long been acknowledged that glycobiological and glycoimmunological aspects play a pivotal role in oral host-microbe, microbe-host, and microbe-microbe interactions in the mouth. In this review, we aim to delineate how glycan-mediated host defense mechanisms in the oral cavity support human health. We will describe the role of glycans attached to large molecular size salivary glycoproteins which act as a first line of primordial host defense in the human mouth. We will further discuss how glycan recognition contributes to both colonization and clearance of oral microbes.
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Affiliation(s)
- Benjamin W Cross
- Department of Oral Biology, University at Buffalo, Buffalo, NY, United States
| | - Stefan Ruhl
- Department of Oral Biology, University at Buffalo, Buffalo, NY, United States.
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22
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Role of Neuraminidase-Producing Bacteria in Exposing Cryptic Carbohydrate Receptors for Streptococcus gordonii Adherence. Infect Immun 2018; 86:IAI.00068-18. [PMID: 29661931 DOI: 10.1128/iai.00068-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 04/13/2018] [Indexed: 12/11/2022] Open
Abstract
Streptococcus gordonii is an early colonizer of the oral cavity. Although a variety of S. gordonii adherence mechanisms have been described, current dogma is that the major receptor for S. gordonii is sialic acid. However, as many bacterial species in the oral cavity produce neuraminidase that can cleave terminal sialic acid, it is unclear whether S. gordonii relies on sialic acid for adherence to oral surfaces or if this species has developed alternative binding strategies. Previous studies have examined adherence to immobilized glycoconjugates and identified binding to additional glycans, but no prior studies have defined the contribution of these different glycan structures in adherence to oral epithelial cells. We determined that the majority of S. gordonii strains tested did not rely on sialic acid for efficient adherence. In fact, adherence of some strains was significantly increased following neuraminidase treatment. Further investigation of representative strains that do not rely on sialic acid for adherence revealed binding not only to sialic acid via the serine-rich repeat protein GspB but also to β-1,4-linked galactose. Adherence to this carbohydrate occurs via an unknown adhesin distinct from those utilized by Streptococcus oralis and Streptococcus pneumoniae Demonstrating the potential biological relevance of binding to this cryptic receptor, we established that S. oralis increases S. gordonii adherence in a neuraminidase-dependent manner. These data suggest that S. gordonii has evolved to simultaneously utilize both terminal and cryptic receptors in response to the production of neuraminidase by other species in the oral environment.
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