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Ali GA, Pérez‐López A, Tsui C, Shunnar K, Sharma A, Ibrahim EB, Tang P, Alsoub H, Goravey W. Streptococcus gordonii-associated infective endocarditis: Case series, literature review, and genetic study. Clin Case Rep 2024; 12:e8684. [PMID: 38585580 PMCID: PMC10996068 DOI: 10.1002/ccr3.8684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 03/02/2024] [Accepted: 03/11/2024] [Indexed: 04/09/2024] Open
Abstract
Key Clinical Message Streptococcus gordonii-associated endocarditis is a rare occurrence, raising diagnostic challenges, and is often associated with considerable morbidity. However, vigilance can prevent devastating consequences. Abstract Streptococcus gordonii-associated endocarditis is rarely reported but often associated with considerable morbidity. We describe three cases of infective endocarditis caused by S. gordonii during a four-week period in 2023, and the use of whole-genome sequencing to determine whether these isolates were genetically related. The available literature was reviewed.
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Affiliation(s)
- Gawahir A. Ali
- Division of Infectious Diseases, Communicable Diseases CentreHamad Medical CorporationDohaQatar
| | - Andrés Pérez‐López
- Department of Pathology and Laboratory MedicineSidra MedicineDohaQatar
- Weill Cornell Medicine in QatarDohaQatar
| | - Clement Tsui
- Division of Infectious Diseases, Faculty of MedicineUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Infectious Diseases Research LaboratoryNational Centre for Infectious DiseasesSingaporeSingapore
- Lee Kong Chian School of MedicineNanyang Technological UniversitySingaporeSingapore
| | - Khalid Shunnar
- Department of cardiologyHamad Medical CorporationDohaQatar
| | - Anju Sharma
- Department of Pathology and Laboratory MedicineSidra MedicineDohaQatar
- Weill Cornell Medicine in QatarDohaQatar
| | - Emad B. Ibrahim
- Division of Microbiology, Department of Laboratory Medicine and PathologyHamad Medical CorporationDohaQatar
- Biomedical Research CentreQatar UniversityDohaQatar
| | - Patrick Tang
- Department of Pathology and Laboratory MedicineSidra MedicineDohaQatar
- Weill Cornell Medicine in QatarDohaQatar
| | - Hussam Alsoub
- Division of Infectious Diseases, Communicable Diseases CentreHamad Medical CorporationDohaQatar
| | - Wael Goravey
- Division of Infectious Diseases, Communicable Diseases CentreHamad Medical CorporationDohaQatar
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2
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Di Carluccio C, Cerofolini L, Moreira M, Rosu F, Padilla-Cortés L, Gheorghita GR, Xu Z, Santra A, Yu H, Yokoyama S, Gray TE, St. Laurent CD, Manabe Y, Chen X, Fukase K, Macauley MS, Molinaro A, Li T, Bensing BA, Marchetti R, Gabelica V, Fragai M, Silipo A. Molecular Insights into O-Linked Sialoglycans Recognition by the Siglec-Like SLBR-N (SLBR UB10712) of Streptococcus gordonii. ACS CENTRAL SCIENCE 2024; 10:447-459. [PMID: 38435526 PMCID: PMC10906241 DOI: 10.1021/acscentsci.3c01598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 03/05/2024]
Abstract
Streptococcus gordonii is a Gram-positive bacterial species that typically colonizes the human oral cavity, but can also cause local or systemic diseases. Serine-rich repeat (SRR) glycoproteins exposed on the S. gordonii bacterial surface bind to sialylated glycans on human salivary, plasma, and platelet glycoproteins, which may contribute to oral colonization as well as endocardial infections. Despite a conserved overall domain organization of SRR adhesins, the Siglec-like binding regions (SLBRs) are highly variable, affecting the recognition of a wide range of sialoglycans. SLBR-N from the SRR glycoprotein of S. gordonii UB10712 possesses the remarkable ability to recognize complex core 2 O-glycans. We here employed a multidisciplinary approach, including flow cytometry, native mass spectrometry, isothermal titration calorimetry, NMR spectroscopy from both protein and ligand perspectives, and computational methods, to investigate the ligand specificity and binding preferences of SLBR-N when interacting with mono- and disialylated core 2 O-glycans. We determined the means by which SLBR-N preferentially binds branched α2,3-disialylated core 2 O-glycans: a selected conformation of the 3'SLn branch is accommodated into the main binding site, driving the sTa branch to further interact with the protein. At the same time, SLBR-N assumes an open conformation of the CD loop of the glycan-binding pocket, allowing one to accommodate the entire complex core 2 O-glycan. These findings establish the basis for the generation of novel tools for the detection of specific complex O-glycan structures and pave the way for the design and development of potential therapeutics against streptococcal infections.
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Affiliation(s)
- Cristina Di Carluccio
- Department
of Chemical Sciences, University of Naples
Federico II, Naples 80138, Italy
| | - Linda Cerofolini
- Magnetic
Resonance Centre (CERM), CIRMMP, and Department of Chemistry “Ugo
Schiff”, University of Florence, Sesto Fiorentino 50019, Italy
| | - Miguel Moreira
- Department
of Chemical Sciences, University of Naples
Federico II, Naples 80138, Italy
| | - Frédéric Rosu
- IECB
Institut Européen de Chimie et Biologie, Pessac 33600, France
| | - Luis Padilla-Cortés
- Magnetic
Resonance Centre (CERM), CIRMMP, and Department of Chemistry “Ugo
Schiff”, University of Florence, Sesto Fiorentino 50019, Italy
| | - Giulia Roxana Gheorghita
- Magnetic
Resonance Centre (CERM), CIRMMP, and Department of Chemistry “Ugo
Schiff”, University of Florence, Sesto Fiorentino 50019, Italy
- Giotto
Biotech s.r.l., Sesto Fiorentino 50019, Italy
| | - Zhuojia Xu
- Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Abhishek Santra
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Hai Yu
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Shinji Yokoyama
- Graduate
School of Science, Osaka University, Osaka 565-0871, Japan
| | - Taylor E. Gray
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - Chris D. St. Laurent
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - Yoshiyuki Manabe
- Graduate
School of Science, Osaka University, Osaka 565-0871, Japan
| | - Xi Chen
- Department
of Chemistry, University of California,
Davis, Davis, California 95616, United States
| | - Koichi Fukase
- Graduate
School of Science, Osaka University, Osaka 565-0871, Japan
| | - Matthew S. Macauley
- Department
of Chemistry, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- Department
of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - Antonio Molinaro
- Department
of Chemical Sciences, University of Naples
Federico II, Naples 80138, Italy
- Graduate
School of Science, Osaka University, Osaka 565-0871, Japan
| | - Tiehai Li
- Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Barbara A. Bensing
- San
Francisco Veterans Affairs Medical Center and University of California, San Francisco, California 94121, United States
| | - Roberta Marchetti
- Department
of Chemical Sciences, University of Naples
Federico II, Naples 80138, Italy
| | - Valérie Gabelica
- IECB
Institut Européen de Chimie et Biologie, Pessac 33600, France
| | - Marco Fragai
- Magnetic
Resonance Centre (CERM), CIRMMP, and Department of Chemistry “Ugo
Schiff”, University of Florence, Sesto Fiorentino 50019, Italy
| | - Alba Silipo
- Department
of Chemical Sciences, University of Naples
Federico II, Naples 80138, Italy
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3
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Altavas PJD, Amoranto MBC, Kim SH, Kang DK, Balolong MP, Dalmacio LMM. Safety assessment of five candidate probiotic lactobacilli using comparative genome analysis. Access Microbiol 2024; 6:000715.v4. [PMID: 38361650 PMCID: PMC10866033 DOI: 10.1099/acmi.0.000715.v4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/16/2024] [Indexed: 02/17/2024] Open
Abstract
Micro-organisms belonging to the Lactobacillus genus complex are often used for oral consumption and are generally considered safe but can exhibit pathogenicity in rare and specific cases. Therefore, screening and understanding genetic factors that may contribute to pathogenicity can yield valuable insights regarding probiotic safety. Limosilactobacillus mucosae LM1, Lactiplantibacillus plantarum SK151, Lactiplantibacillus plantarum BS25, Limosilactobacillus fermentum SK152 and Lactobacillus johnsonii PF01 are current probiotics of interest; however, their safety profiles have not been explored. The genome sequences of LM1, SK151, SK152 and PF01 were downloaded from the NCBI GenBank, while that of L. plantarum BS25 was newly sequenced. These genomes were then annotated using the Rapid Annotation using Subsystem Technology tool kit pipeline. Subsequently, a command line blast was performed against the Virulence Factor Database (VFDB) and the Comprehensive Antibiotic Resistance Database (CARD) to identify potential virulence factors and antibiotic resistance (AR) genes. Furthermore, ResFinder was used to detect acquired AR genes. The query against the VFDB identified genes that have a role in bacterial survivability, platelet aggregation, surface adhesion, biofilm formation and immunoregulation; and no acquired AR genes were detected using CARD and ResFinder. The study shows that the query strains exhibit genes identical to those present in pathogenic bacteria with the genes matched primarily having roles related to survival and surface adherence. Our results contribute to the overall strategies that can be employed in pre-clinical safety assessments of potential probiotics. Gene mining using whole-genome data, coupled with experimental validation, can be implemented in future probiotic safety assessment strategies.
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Affiliation(s)
- Patrick Josemaria d.R Altavas
- Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Ermita, Manila 1000, Philippines
| | - Mia Beatriz C. Amoranto
- Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Ermita, Manila 1000, Philippines
| | - Sang Hoon Kim
- Department of Animal Resources Science, College of Biotechnology and Bioengineering, Dankook University, Gyeonggi-do, Republic of Korea
| | - Dae-Kyung Kang
- Department of Animal Resources Science, College of Biotechnology and Bioengineering, Dankook University, Gyeonggi-do, Republic of Korea
| | - Marilen P. Balolong
- Department of Biology, College of Arts and Sciences, University of the Philippines Manila, Ermita, Manila 1000, Philippines
| | - Leslie Michelle M. Dalmacio
- Department of Biochemistry and Molecular Biology, College of Medicine, University of the Philippines Manila, Ermita, Manila 1000, Philippines
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4
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Nasir SN, Iftikhar A, Zubair F, Alshammari A, Alharbi M, Alasmari AF, Khan A, Waseem M, Ali SS, Ali L, Waheed Y, Wei DQ. Structural vaccinology-based design of multi-epitopes vaccine against Streptococcus gordonii and validation using molecular modeling and immune simulation approaches. Heliyon 2023; 9:e16148. [PMID: 37234653 PMCID: PMC10208844 DOI: 10.1016/j.heliyon.2023.e16148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 05/02/2023] [Accepted: 05/07/2023] [Indexed: 05/28/2023] Open
Abstract
Streptococcus gordonii is an oral bacterium colonizing the dental cavity and leading to plaque formation. This pervasive colonizer is also the etiologic agent of bacterial endocarditis and has a major role in infective endocarditis. The bacteria reach the heart through oral bleeding, leading to inflammation of cardiovascular valves. Over the past 50 years, it has shown a significant pathogenic role in immunocompromised and neutropenic patients. Since antibiotic resistance has created prophylaxis failure towards infective endocarditis, a potent therapeutic candidate is needed. Therefore, multi-epitopes vaccine offers advantages over the other approaches. Thus, herein, numerous molecular-omics tools were exploited to mine immunogenic peptides, i.e., T-cell and B-cell epitopes, and construct a vaccine sequence. Our findings revealed a total of 24 epitopes, including CTL, HTL, and B-cell are responsible for imparting immune responses, which were combined with the help of different linkers, and MEVC was constructed. Multifactorial validation of the candidate vaccine was performed to minimize the risk factors. The final sequence was docked with TLR2 to validate its conformation compatibility with receptor and long-term interactions stability. Our analysis revealed that the vaccine construct is immunogenic and non-allergenic. The construct also established various contacts with the immune receptor. Finally, the vaccine sequence was reverse-translated, optimized for codon usage, and analyzed for expression in the Escherichia coli K12 strain. Maximum expression was noted with a CAI score of 0.95. In silico immune simulation revealed that the antigen was neutralized on the 3rd day after injection. In conclusion, the current study warrants validation of the vaccine construct both in in vitro and in vivo models for accurate therapeutic intervention.
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Affiliation(s)
- Syed Nouman Nasir
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Punjab, Pakistan
| | - Ayesha Iftikhar
- Government Khwaja Muhammad Safdar Medical College, Sialkot, Punjab, Pakistan
| | - Farukh Zubair
- Rashid Latif Medical College, Lahore, Punjab, Pakistan
| | - Abdulrahman Alshammari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, Riyadh, 11451, Saudi Arabia
| | - Metab Alharbi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, Riyadh, 11451, Saudi Arabia
| | - Abdullah F. Alasmari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, Riyadh, 11451, Saudi Arabia
| | - Abbas Khan
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China
- Zhongjing Research and Industrialization Institute of Chinese Medicine, Zhongguancun Scientific Park, Meixi, Nayang, Henan, 473006, PR China
| | - Muhammad Waseem
- Faculty of Rehabilitation and Allied Health Science, Riphah International University, Islamabad, Pakistan
| | - Syed Shujait Ali
- National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Punjab, Pakistan
| | - Liaqat Ali
- Fisch College of Pharmacy, The University of Texas at Tyler, Tyler, TX, USA
| | - Yasir Waheed
- Office of Research, Innovation, and Commercialization (ORIC), Shaheed Zulfiqar Ali Bhutto Medical University (SZABMU), Islamabad, 44000, Pakistan
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, Byblos, 1401, Lebanon
| | - Dong-Qing Wei
- Department of Bioinformatics and Biological Statistics, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, 200240, PR China
- Zhongjing Research and Industrialization Institute of Chinese Medicine, Zhongguancun Scientific Park, Meixi, Nayang, Henan, 473006, PR China
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5
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Cho WM, Lee JS, Chung SW, Ahn TK. Infectious Spondylitis Caused by Streptococcus gordonii. Cureus 2023; 15:e36657. [PMID: 37102019 PMCID: PMC10123389 DOI: 10.7759/cureus.36657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2023] [Indexed: 04/28/2023] Open
Abstract
Infectious spondylitis is a rare but severe disease of the spine caused by bacteria or other pathogens. Particularly in immunocompromised patients, a definitive source of infection often remains uncertain. Among many pathogens, Streptococcus gordonii, a normal oral flora, is a very rare pathogen in infectious spondylitis. Only a few articles have reported infectious spondylitis caused by Streptococcus gordonii. To the best of our knowledge, there have been no reports of surgically treated infectious spondylitis caused by Streptococcus gordonii. Hence, in the current report, we present the case of a 76-year-old woman with known type 2 diabetes who was transferred to our medical center due to infectious spondylitis caused by Streptococcus gordonii following an L1 compression fracture and underwent an operation for treatment.
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Affiliation(s)
- Weon-Min Cho
- Department of Orthopedic Surgery, CHA Bundang Medical Center, CHA University School of Medicine, Sungnam, KOR
| | - Ju-Sung Lee
- Department of Orthopedic Surgery, CHA Bundang Medical Center, CHA University School of Medicine, Sungnam, KOR
| | - Seung-Won Chung
- Department of Dentistry, CHA Bundang Medical Center, Sungnam, KOR
| | - Tae-Keun Ahn
- Department of Orthopedic Surgery, CHA University, CHA Bundang Medical Center, Sungnam, KOR
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6
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Yan LF, Zhang J, Zhang Z. Reactive arthritis and subacute infective endocarditis caused by Streptococcus gordonii infection: A case report. Int J Rheum Dis 2023; 26:376-378. [PMID: 36314763 DOI: 10.1111/1756-185x.14481] [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: 09/07/2022] [Revised: 10/08/2022] [Accepted: 10/14/2022] [Indexed: 01/28/2023]
Abstract
Streptococcus gordonii (S. gordonii) belongs to the alpha-hemolytic Streptococcus group. It is a symbiotic bacterium found in the human oral mucosa which is present in large quantities on the surface of the teeth. It is generally considered nonpathogenic or weakly pathogenic and is known to cause subacute endocarditis; however, there are few reports of reactive arthritis (ReA) caused by S. gordonii. Herein, we report a case of ReA complicated by subacute infective endocarditis caused by S. gordonii and explore the possible pathogenic mechanism of ReA caused by S. gordonii.
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Affiliation(s)
- Li-Fang Yan
- Department of Rheumatism and Immunology, Qinghai Red Cross Hospital, Xining, China
| | - Jie Zhang
- Department of Rheumatism and Immunology, Qinghai Red Cross Hospital, Xining, China
| | - Zhen Zhang
- Department of Rheumatism and Immunology, Qinghai Red Cross Hospital, Xining, China
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7
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Okahashi N, Nakata M, Kuwata H, Kawabata S. Oral mitis group streptococci: A silent majority in our oral cavity. Microbiol Immunol 2022; 66:539-551. [PMID: 36114681 DOI: 10.1111/1348-0421.13028] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/11/2022] [Accepted: 09/12/2022] [Indexed: 12/13/2022]
Abstract
Members of the oral mitis group streptococci including Streptococcus oralis, Streptococcus sanguinis, and Streptococcus gordonii are the most abundant inhabitants of human oral cavity and dental plaque, and have been implicated in infectious complications such as bacteremia and infective endocarditis. Oral mitis group streptococci are genetically close to Streptococcus pneumoniae; however, they do not produce cytolysin (pneumolysin), which is a key virulence factor of S. pneumoniae. Similar to S. pneumoniae, oral mitis group streptococci possess several cell surface proteins that bind to the cell surface components of host mammalian cells. S. sanguinis expresses long filamentous pili that bind to the matrix proteins of host cells. The cell wall-anchored nuclease of S. sanguinis contributes to the evasion of the neutrophil extracellular trap by digesting its web-like extracellular DNA. Oral mitis group streptococci produce glucosyltransferases, which synthesize glucan (glucose polymer) from sucrose of dietary origin. Neuraminidase (NA) is a virulent factor in oral mitis group streptococci. Influenza type A virus (IAV) relies on viral NA activity to release progeny viruses from infected cells and spread the infection, and NA-producing oral streptococci elevate the risk of IAV infection. Moreover, oral mitis group streptococci produce hydrogen peroxide (H2 O2 ) as a by-product of sugar metabolism. Although the concentrations of streptococcal H2 O2 are low (1-2 mM), they play important roles in bacterial competition in the oral cavity and evasion of phagocytosis by host macrophages and neutrophils. In this review, we intended to describe the diverse pathogenicity of oral mitis group streptococci.
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Affiliation(s)
- Nobuo Okahashi
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan.,Center for Frontier Oral Science, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
| | - Masanobu Nakata
- Department of Oral Microbiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hirotaka Kuwata
- Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, Shinagawa, Tokyo, Japan
| | - Shigetada Kawabata
- Department of Oral and Molecular Microbiology, Osaka University Graduate School of Dentistry, Suita, Osaka, Japan
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8
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Bensing BA, Stubbs HE, Agarwal R, Yamakawa I, Luong K, Solakyildirim K, Yu H, Hadadianpour A, Castro MA, Fialkowski KP, Morrison KM, Wawrzak Z, Chen X, Lebrilla CB, Baudry J, Smith JC, Sullam PM, Iverson TM. Origins of glycan selectivity in streptococcal Siglec-like adhesins suggest mechanisms of receptor adaptation. Nat Commun 2022; 13:2753. [PMID: 35585145 PMCID: PMC9117288 DOI: 10.1038/s41467-022-30509-y] [Citation(s) in RCA: 3] [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: 04/10/2021] [Accepted: 04/26/2022] [Indexed: 11/22/2022] Open
Abstract
Bacterial binding to host receptors underlies both commensalism and pathogenesis. Many streptococci adhere to protein-attached carbohydrates expressed on cell surfaces using Siglec-like binding regions (SLBRs). The precise glycan repertoire recognized may dictate whether the organism is a strict commensal versus a pathogen. However, it is currently not clear what drives receptor selectivity. Here, we use five representative SLBRs and identify regions of the receptor binding site that are hypervariable in sequence and structure. We show that these regions control the identity of the preferred carbohydrate ligand using chimeragenesis and single amino acid substitutions. We further evaluate how the identity of the preferred ligand affects the interaction with glycoprotein receptors in human saliva and plasma samples. As point mutations can change the preferred human receptor, these studies suggest how streptococci may adapt to changes in the environmental glycan repertoire.
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Affiliation(s)
- Barbara A Bensing
- Division of Infectious Diseases, Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA, USA
- the Northern California Institute for Research and Education, San Francisco, CA, 94121, USA
| | - Haley E Stubbs
- Graduate Program in Chemical and Physical Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Rupesh Agarwal
- University of Tennessee/Oak Ridge National Laboratory, Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6309, USA
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Izumi Yamakawa
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
- School of Nursing, Belmont University, Nashville, TN, 37212, USA
| | - Kelvin Luong
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Kemal Solakyildirim
- Department of Chemistry, Erzincan Binali Yildirim University, Erzincan, 24100, Turkey
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Hai Yu
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Azadeh Hadadianpour
- Department of Microbiology, Pathology, and Immunology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Manuel A Castro
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA
| | - Kevin P Fialkowski
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA
- College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - KeAndreya M Morrison
- Department of Pharmacology, School of Graduate Studies and Research, Meharry Medical College, Nashville, TN, 37208, USA
| | - Zdzislaw Wawrzak
- LS-CAT Synchrotron Research Center, Northwestern University, Argonne, IL, 60439, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Carlito B Lebrilla
- Department of Chemistry, University of California, Davis, CA, 95616, USA
| | - Jerome Baudry
- Department of Biological Sciences, The University of Alabama in Huntsville, Huntsville, AL, 35899, USA
| | - Jeremy C Smith
- University of Tennessee/Oak Ridge National Laboratory, Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831-6309, USA
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Paul M Sullam
- Division of Infectious Diseases, Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco, CA, USA
- the Northern California Institute for Research and Education, San Francisco, CA, 94121, USA
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN, 37232, USA.
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA.
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9
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Aceil J, Avci FY. Pneumococcal Surface Proteins as Virulence Factors, Immunogens, and Conserved Vaccine Targets. Front Cell Infect Microbiol 2022; 12:832254. [PMID: 35646747 PMCID: PMC9133333 DOI: 10.3389/fcimb.2022.832254] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 04/13/2022] [Indexed: 11/13/2022] Open
Abstract
Streptococcus pneumoniae is an opportunistic pathogen that causes over 1 million deaths annually despite the availability of several multivalent pneumococcal conjugate vaccines (PCVs). Due to the limitations surrounding PCVs along with an evolutionary rise in antibiotic-resistant and unencapsulated strains, conserved immunogenic proteins as vaccine targets continue to be an important field of study for pneumococcal disease prevention. In this review, we provide an overview of multiple classes of conserved surface proteins that have been studied for their contribution to pneumococcal virulence. Furthermore, we discuss the immune responses observed in response to these proteins and their promise as vaccine targets.
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10
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Lemaire C, Le Gallou B, Lanotte P, Mereghetti L, Pastuszka A. Distribution, Diversity and Roles of CRISPR-Cas Systems in Human and Animal Pathogenic Streptococci. Front Microbiol 2022; 13:828031. [PMID: 35173702 PMCID: PMC8841824 DOI: 10.3389/fmicb.2022.828031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/10/2022] [Indexed: 12/26/2022] Open
Abstract
Streptococci form a wide group of bacteria and are involved in both human and animal pathologies. Among pathogenic isolates, differences have been highlighted especially concerning their adaptation and virulence profiles. CRISPR-Cas systems have been identified in bacteria and many streptococci harbor one or more systems, particularly subtypes I-C, II-A, and III-A. Since the demonstration that CRISPR-Cas act as an adaptive immune system in Streptococcus thermophilus, a lactic bacteria, the diversity and role of CRISPR-Cas were extended to many germs and functions were enlarged. Among those, the genome editing tool based on the properties of Cas endonucleases is used worldwide, and the recent attribution of the Nobel Prize illustrates the importance of this tool in the scientific world. Another application is CRISPR loci analysis, which allows to easily characterize isolates in order to understand the interactions of bacteria with their environment and visualize species evolution. In this review, we focused on the distribution, diversity and roles of CRISPR-Cas systems in the main pathogenic streptococci.
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Affiliation(s)
- Coralie Lemaire
- Université de Tours, INRAE, Infectiologie et Santé Publique, BRMF, Tours, France
- Service de Bactériologie-Virologie, Centre Hospitalier Régional Universitaire de Tours, Tours, France
| | - Brice Le Gallou
- Université de Tours, INRAE, Infectiologie et Santé Publique, BRMF, Tours, France
- Service de Bactériologie-Virologie, Centre Hospitalier Régional Universitaire de Tours, Tours, France
| | - Philippe Lanotte
- Université de Tours, INRAE, Infectiologie et Santé Publique, BRMF, Tours, France
- Service de Bactériologie-Virologie, Centre Hospitalier Régional Universitaire de Tours, Tours, France
- *Correspondence: Philippe Lanotte,
| | - Laurent Mereghetti
- Université de Tours, INRAE, Infectiologie et Santé Publique, BRMF, Tours, France
- Service de Bactériologie-Virologie, Centre Hospitalier Régional Universitaire de Tours, Tours, France
| | - Adeline Pastuszka
- Université de Tours, INRAE, Infectiologie et Santé Publique, BRMF, Tours, France
- Service de Bactériologie-Virologie, Centre Hospitalier Régional Universitaire de Tours, Tours, France
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11
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Di Carluccio C, Forgione RE, Bosso A, Yokoyama S, Manabe Y, Pizzo E, Molinaro A, Fukase K, Fragai M, Bensing BA, Marchetti R, Silipo A. Molecular recognition of sialoglycans by streptococcal Siglec-like adhesins: toward the shape of specific inhibitors. RSC Chem Biol 2021; 2:1618-1630. [PMID: 34977577 PMCID: PMC8637897 DOI: 10.1039/d1cb00173f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/14/2021] [Indexed: 01/16/2023] Open
Abstract
Streptococcus gordonii and Streptococcus sanguinis, commensal bacteria present in the oral cavity of healthy individuals, upon entry into the bloodstream can become pathogenic, causing infective endocarditis (IE). Sialic acid-binding serine-rich repeat adhesins on the microbial surface represent an important factor of successful infection to cause IE. They contain Siglec-like binding regions (SLBRs) that variously recognize different repertoires of O-glycans, with some strains displaying high selectivity and others broader specificity. We here dissect at an atomic level the mechanism of interaction of SLBR-B and SLBR-H from S. gordonii with a multivarious approach that combines NMR spectroscopy and computational and biophysical studies. The binding pockets of both SLBRs are broad enough to accommodate extensive interactions with sialoglycans although with key differences related to strain specificity. Furthermore, and significantly, the pattern of interactions established by the SLBRs are mechanistically very different from those reported for mammalian Siglecs despite them having a similar fold. Thus, our detailed description of the binding modes of streptococcal Siglec-like adhesins sparks the development of tailored synthetic inhibitors and therapeutics specific for Streptococcal adhesins to counteract IE, without impairing the interplay between Siglecs and glycans. We here present a detailed molecular description of sialoglycans recognition by Siglec-like adhesins from S. gordonii opening the venue for the design of specific inhibitors to influence the propensity of streptococci to cause infective endocarditis.![]()
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Affiliation(s)
- Cristina Di Carluccio
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Rosa Ester Forgione
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Andrea Bosso
- Department of Biology, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Shinji Yokoyama
- Department of Chemistry, Graduate School of Science, Osaka University 1-1 Machikaneyama Toyonaka Osaka 560-0043 Japan
| | - Yoshiyuki Manabe
- Department of Chemistry, Graduate School of Science, Osaka University 1-1 Machikaneyama Toyonaka Osaka 560-0043 Japan
| | - Elio Pizzo
- Department of Biology, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Antonio Molinaro
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy .,Department of Chemistry, Graduate School of Science, Osaka University 1-1 Machikaneyama Toyonaka Osaka 560-0043 Japan
| | - Koichi Fukase
- Department of Chemistry, Graduate School of Science, Osaka University 1-1 Machikaneyama Toyonaka Osaka 560-0043 Japan
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP) Via L. Sacconi 6 50019 Sesto Fiorentino Italy.,Department of Chemistry "Ugo Schiff", University of Florence Via della Lastruccia 3-13 50019 Sesto Fiorentino Italy
| | - Barbara A Bensing
- Division of Infectious Diseases, Veterans Affairs Medical Center, Department of Medicine, University of California San Francisco California 94121 USA.,Northern California Institute for Research and Education San Francisco California 94121 USA
| | - Roberta Marchetti
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
| | - Alba Silipo
- Department of Chemical Sciences, University of Naples Federico II Via Cinthia 4 80126 Naples Italy
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12
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Solakyildirim K, Li Y, Bayer AS, Sullam PM, Xiong YQ, Lebrilla CB, Bensing BA. Proteoglycan 4 (lubricin) is a highly sialylated glycoprotein associated with cardiac valve damage in animal models of infective endocarditis. Glycobiology 2021; 31:1582-1595. [PMID: 34459483 DOI: 10.1093/glycob/cwab095] [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: 05/21/2021] [Revised: 07/30/2021] [Accepted: 08/16/2021] [Indexed: 11/12/2022] Open
Abstract
S. gordonii and S. sanguinis are primary colonizers of tooth surfaces, and are generally associated with oral health, but can also cause infective endocarditis (IE). These species express "Siglec-like" adhesins that bind sialylated glycans on host glycoproteins, which can aid the formation of infected platelet-fibrin thrombi (vegetations) on cardiac valve surfaces. We previously determined that the ability of S. gordonii to bind sialyl T-antigen (sTa) increased pathogenicity, relative to recognition of sialylated core 2 O-glycan structures, in an animal model of IE. However, it is unclear when and where the sTa structure is displayed, and which sTa-modified host factors promote valve colonization. In this study, we identified sialylated glycoproteins in the aortic valve vegetations and plasma of rat and rabbit models of this disease. Glycoproteins that display sTa versus core 2 O-glycan structures were identified by using recombinant forms of the streptococcal Siglec-like adhesins for lectin blotting and affinity capture, and the O-linked glycans were profiled by mass spectrometry. Proteoglycan 4 (PRG4), also known as lubricin, was a major carrier of sTa in the infected vegetations. Moreover, plasma PRG4 levels were significantly higher in animals with damaged or infected valves, as compared with healthy animals. The combined results demonstrate that, in addition to platelet GPIbα, PRG4 is a highly sialylated mucin-like glycoprotein found in aortic valve vegetations and may contribute to the persistence of oral streptococci in this protected endovascular niche. Moreover, plasma PRG4 could serve as a biomarker for endocardial injury and infection.
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Affiliation(s)
- Kemal Solakyildirim
- Department of Chemistry, University of California, Davis, California, United States of America.,Department of Chemistry, Erzincan Binali Yildirim University, Erzincan, 24100, Turkey
| | - Yi Li
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Arnold S Bayer
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America.,David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Paul M Sullam
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, California, United States of America
| | - Yan Q Xiong
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America.,David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Carlito B Lebrilla
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Barbara A Bensing
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, California, United States of America
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13
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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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14
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Seepersaud R, Anderson AC, Bensing BA, Choudhury BP, Clarke AJ, Sullam PM. O-acetylation controls the glycosylation of bacterial serine-rich repeat glycoproteins. J Biol Chem 2021; 296:100249. [PMID: 33384382 PMCID: PMC7948813 DOI: 10.1074/jbc.ra120.016116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 12/21/2020] [Accepted: 12/31/2020] [Indexed: 01/14/2023] Open
Abstract
The serine-rich repeat (SRR) glycoproteins of gram-positive bacteria are a family of adhesins that bind to a wide range of host ligands, and expression of SRR glycoproteins is linked with enhanced bacterial virulence. The biogenesis of these surface glycoproteins involves their intracellular glycosylation and export via the accessory Sec system. Although all accessory Sec components are required for SRR glycoprotein export, Asp2 of Streptococcus gordonii also functions as an O-acetyltransferase that modifies GlcNAc residues on the SRR adhesin gordonii surface protein B (GspB). Because these GlcNAc residues can also be modified by the glycosyltransferases Nss and Gly, it has been unclear whether the post-translational modification of GspB is coordinated. We now report that acetylation modulates the glycosylation of exported GspB. Loss of O-acetylation due to aps2 mutagenesis led to the export of GspB glycoforms with increased glucosylation of the GlcNAc moieties. Linkage analysis of the GspB glycan revealed that both O-acetylation and glucosylation occurred at the same C6 position on GlcNAc residues and that O-acetylation prevented Glc deposition. Whereas streptococci expressing nonacetylated GspB with increased glucosylation were significantly reduced in their ability to bind human platelets in vitro, deletion of the glycosyltransferases nss and gly in the asp2 mutant restored platelet binding to WT levels. These findings demonstrate that GlcNAc O-acetylation controls GspB glycosylation, such that binding via this adhesin is optimized. Moreover, because O-acetylation has comparable effects on the glycosylation of other SRR adhesins, acetylation may represent a conserved regulatory mechanism for the post-translational modification of the SRR glycoprotein family.
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Affiliation(s)
- Ravin Seepersaud
- Department of Medicine, Division of Infectious Diseases, San Francisco Veteran Affairs Medical Center, and the Department of Medicine, University of California, San Francisco, California, USA
| | - Alexander C Anderson
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Barbara A Bensing
- Department of Medicine, Division of Infectious Diseases, San Francisco Veteran Affairs Medical Center, and the Department of Medicine, University of California, San Francisco, California, USA
| | - Biswa P Choudhury
- GlycoAnalytics Core, University of California, San Diego, San Diego, California, USA
| | - Anthony J Clarke
- Department of Chemistry and Biochemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada
| | - Paul M Sullam
- Department of Medicine, Division of Infectious Diseases, San Francisco Veteran Affairs Medical Center, and the Department of Medicine, University of California, San Francisco, California, USA.
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15
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Park OJ, Kwon Y, Park C, So YJ, Park TH, Jeong S, Im J, Yun CH, Han SH. Streptococcus gordonii: Pathogenesis and Host Response to Its Cell Wall Components. Microorganisms 2020; 8:microorganisms8121852. [PMID: 33255499 PMCID: PMC7761167 DOI: 10.3390/microorganisms8121852] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 11/23/2020] [Accepted: 11/23/2020] [Indexed: 02/08/2023] Open
Abstract
Streptococcus gordonii, a Gram-positive bacterium, is a commensal bacterium that is commonly found in the skin, oral cavity, and intestine. It is also known as an opportunistic pathogen that can cause local or systemic diseases, such as apical periodontitis and infective endocarditis. S. gordonii, an early colonizer, easily attaches to host tissues, including tooth surfaces and heart valves, forming biofilms. S. gordonii penetrates into root canals and blood streams, subsequently interacting with various host immune and non-immune cells. The cell wall components of S. gordonii, which include lipoteichoic acids, lipoproteins, serine-rich repeat adhesins, peptidoglycans, and cell wall proteins, are recognizable by individual host receptors. They are involved in virulence and immunoregulatory processes causing host inflammatory responses. Therefore, S.gordonii cell wall components act as virulence factors that often progressively develop diseases through overwhelming host responses. This review provides an overview of S. gordonii, and how its cell wall components could contribute to the pathogenesis and development of therapeutic strategies.
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Affiliation(s)
- Ok-Jin Park
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Yeongkag Kwon
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Chaeyeon Park
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Yoon Ju So
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Tae Hwan Park
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Sungho Jeong
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Jintaek Im
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea;
- Institute of Green Bio Science Technology, Seoul National University, Pyeongchang 25354, Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, School of Dentistry, Dental Research Institute, Seoul National University, Seoul 08826, Korea; (O.-J.P.); (Y.K.); (C.P.); (Y.J.S.); (T.H.P.); (S.J.); (J.I.)
- Correspondence: ; Tel.: +82-2-880-2310
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16
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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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17
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Abstract
In addition to SecA of the general Sec system, many Gram-positive bacteria, including mycobacteria, express SecA2, a second, transport-associated ATPase. SecA2s can be subdivided into two mechanistically distinct types: (i) SecA2s that are part of the accessory Sec (aSec) system, a specialized transporter mediating the export of a family of serine-rich repeat (SRR) glycoproteins that function as adhesins, and (ii) SecA2s that are part of multisubstrate systems, in which SecA2 interacts with components of the general Sec system, specifically the SecYEG channel, to export multiple types of substrates. Found mainly in streptococci and staphylococci, the aSec system also contains SecY2 and novel accessory Sec proteins (Asps) that are required for optimal export. Asp2 also acetylates glucosamine residues on the SRR domains of the substrate during transport. Targeting of the SRR substrate to SecA2 and the aSec translocon is mediated by a specialized signal peptide. Multisubstrate SecA2 systems are present in mycobacteria, corynebacteria, listeriae, clostridia, and some bacillus species. Although most substrates for this SecA2 have canonical signal peptides that are required for export, targeting to SecA2 appears to depend on structural features of the mature protein. The feature of the mature domains of these proteins that renders them dependent on SecA2 for export may be their potential to fold in the cytoplasm. The discovery of aSec and multisubstrate SecA2 systems expands our appreciation of the diversity of bacterial export pathways. Here we present our current understanding of the mechanisms of each of these SecA2 systems.
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18
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Martini AM, Moricz BS, Ripperger AK, Tran PM, Sharp ME, Forsythe AN, Kulhankova K, Salgado-Pabón W, Jones BD. Association of Novel Streptococcus sanguinis Virulence Factors With Pathogenesis in a Native Valve Infective Endocarditis Model. Front Microbiol 2020; 11:10. [PMID: 32082276 PMCID: PMC7005726 DOI: 10.3389/fmicb.2020.00010] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 01/06/2020] [Indexed: 12/11/2022] Open
Abstract
Streptococcus sanguinis (S. sanguinis) is an abundant oral commensal which can cause disseminated human infection if it gains access to the bloodstream. The most important among these diseases is infective endocarditis (IE). While virulence phenotypes of S. sanguinis have been correlated to disease severity, genetic factors mediating these phenotypes, and contributing to pathogenesis are largely uncharacterized. In this report, we investigate the roles of 128 genes in virulence-related phenotypes of S. sanguinis and characterize the pathogenic potential of two selected mutants in a left-sided, native valve IE rabbit model. Assays determining the ability of our mutant strains to produce a biofilm, bind to and aggregate platelets, and adhere to or invade endothelial cells identified sixteen genes with novel association to these phenotypes. These results suggest the presence of many uncharacterized genes involved in IE pathogenesis which may be relevant for disease progression. Two mutants identified by the above screening process – SSA_1099, encoding an RTX-like protein, and mur2, encoding a peptidoglycan hydrolase – were subsequently evaluated in vivo. Wild type (WT) S. sanguinis reliably induced cardiac vegetations, while the SSA_1099 and mur2 mutants produced either no vegetation or vegetations of small size. Splenomegaly was reduced in both mutant strains compared to WT, while pathology of other distal organs was indistinguishable. Histopathology analyses suggest the cardiac lesions and vegetations in this model resemble those observed in humans. These data indicate that SSA_1099 and mur2 encode virulence factors in S. sanguinis which are integral to pathogenesis of IE.
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Affiliation(s)
- Anthony M Martini
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Bridget S Moricz
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Allison K Ripperger
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Phuong M Tran
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Molly E Sharp
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Ana N Forsythe
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Katarina Kulhankova
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Wilmara Salgado-Pabón
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States
| | - Bradley D Jones
- Department of Microbiology & Immunology, The Roy J. and Lucille A. Carver College of Medicine, The University of Iowa, Iowa City, IA, United States.,Graduate Program in Genetics, The University of Iowa, Iowa City, IA, United States
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19
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The Pathogenic Factors from Oral Streptococci for Systemic Diseases. Int J Mol Sci 2019; 20:ijms20184571. [PMID: 31540175 PMCID: PMC6770522 DOI: 10.3390/ijms20184571] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/11/2019] [Accepted: 09/14/2019] [Indexed: 02/06/2023] Open
Abstract
The oral cavity is suggested as the reservoir of bacterial infection, and the oral and pharyngeal biofilms formed by oral bacterial flora, which is comprised of over 700 microbial species, have been found to be associated with systemic conditions. Almost all oral microorganisms are non-pathogenic opportunistic commensals to maintain oral health condition and defend against pathogenic microorganisms. However, oral Streptococci, the first microorganisms to colonize oral surfaces and the dominant microorganisms in the human mouth, has recently gained attention as the pathogens of various systemic diseases, such as infective endocarditis, purulent infections, brain hemorrhage, intestinal inflammation, and autoimmune diseases, as well as bacteremia. As pathogenic factors from oral Streptococci, extracellular polymeric substances, toxins, proteins and nucleic acids as well as vesicles, which secrete these components outside of bacterial cells in biofilm, have been reported. Therefore, it is necessary to consider that the relevance of these pathogenic factors to systemic diseases and also vaccine candidates to protect infectious diseases caused by Streptococci. This review article focuses on the mechanistic links among pathogenic factors from oral Streptococci, inflammation, and systemic diseases to provide the current understanding of oral biofilm infections based on biofilm and widespread systemic diseases.
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Bensing BA, Li L, Yakovenko O, Wong M, Barnard KN, Iverson TM, Lebrilla CB, Parrish CR, Thomas WE, Xiong Y, Sullam PM. Recognition of specific sialoglycan structures by oral streptococci impacts the severity of endocardial infection. PLoS Pathog 2019; 15:e1007896. [PMID: 31233555 PMCID: PMC6611644 DOI: 10.1371/journal.ppat.1007896] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/05/2019] [Accepted: 06/05/2019] [Indexed: 11/18/2022] Open
Abstract
Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of the tooth surface. Although generally non-pathogenic in the oral environment, they are a frequent cause of infective endocarditis. Both streptococcal species express a serine-rich repeat surface adhesin that mediates attachment to sialylated glycans on mucin-like glycoproteins, but the specific sialoglycan structures recognized can vary from strain to strain. Previous studies have shown that sialoglycan binding is clearly important for aortic valve infections caused by some S. gordonii, but this process did not contribute to the virulence of a strain of S. sanguinis. However, these streptococci can bind to different subsets of sialoglycan structures. Here we generated isogenic strains of S. gordonii that differ only in the type and range of sialoglycan structures to which they adhere and examined whether this rendered them more or less virulent in a rat model of endocarditis. The findings indicate that the recognition of specific sialoglycans can either enhance or diminish pathogenicity. Binding to sialyllactosamine reduces the initial colonization of mechanically-damaged aortic valves, whereas binding to the closely-related trisaccharide sialyl T-antigen promotes higher bacterial densities in valve tissue 72 hours later. A surprising finding was that the initial attachment of streptococci to aortic valves was inversely proportional to the affinity of each strain for platelets, suggesting that binding to platelets circulating in the blood may divert bacteria away from the endocardial surface. Importantly, we found that human and rat platelet GPIbα (the major receptor for S. gordonii and S. sanguinis on platelets) display similar O-glycan structures, comprised mainly of a di-sialylated core 2 hexasaccharide, although the rat GPIbα has a more heterogenous composition of modified sialic acids. The combined results suggest that streptococcal interaction with a minor O-glycan on GPIbα may be more important than the over-all affinity for GPIbα for pathogenic effects. Infective endocarditis (IE) is a life-threatening infection of heart valves, and streptococci that normally reside in the mouth are a leading cause of this disease. Some oral streptococcal species express a protein on their surface that enables attachment to glycan (sugar) modifications on saliva proteins, an interaction that may be important for colonization of the tooth and other oral surfaces. These "Siglec-like adhesins" are hypervariable in the type and number of glycan structures they bind, ranging from just one to more than six of the structures displayed on the saliva proteins. If streptococci enter into the bloodstream, the Siglec-like adhesin can mediate attachment to similar glycans that decorate platelet or plasma proteins, which can impact the overall virulence of the organism. This study highlights how recognition of a specific type of glycan structure can cause a generally beneficial or neutral microbe to create damage to specific tissues—in this case the heart valves, illustrating one means by which commensal bacteria can become opportunistic or accidental pathogens. The findings further indicate that certain glycan-binding streptococci among the oral microbiota may be predisposed to produce infective endocarditis.
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Affiliation(s)
- Barbara A. Bensing
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, California, United States of America
- * E-mail:
| | - Liang Li
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Olga Yakovenko
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Maurice Wong
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Karen N. Barnard
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - T. M. Iverson
- Departments of Pharmacology and Biochemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Carlito B. Lebrilla
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Colin R. Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Wendy E. Thomas
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Yan Xiong
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California, United States of America
- David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Paul M. Sullam
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, California, United States of America
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Streptococcus gordonii: A Rare Cause of Infective Endocarditis. Case Rep Infect Dis 2019; 2019:7127848. [PMID: 31281690 PMCID: PMC6594294 DOI: 10.1155/2019/7127848] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 05/14/2019] [Accepted: 05/30/2019] [Indexed: 12/05/2022] Open
Abstract
Infective endocarditis is a rare but life-threatening disease seen across the globe. Organisms from the oral cavity still represent a large proportion of pathogens seen in endocarditis and can be from either daily dental routines or invasive procedures. With the recent changes to antibiotic prophylaxis for infective endocarditis prior to dental procedures, the physician must have a heightened degree of suspicion when presented with a patient with undifferenced sepsis following dental procedures. The authors present a case of infective endocarditis caused by Streptococcus gordonii after the drainage of a dental abscess.
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22
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Latousakis D, MacKenzie DA, Telatin A, Juge N. Serine-rich repeat proteins from gut microbes. Gut Microbes 2019; 11:102-117. [PMID: 31035824 PMCID: PMC6973325 DOI: 10.1080/19490976.2019.1602428] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 03/08/2019] [Accepted: 03/27/2019] [Indexed: 02/03/2023] Open
Abstract
Serine-rich repeat proteins (SRRPs) have emerged as an important group of cell surface adhesins found in a growing number of Gram-positive bacteria. Studies focused on SRRPs from streptococci and staphylococci demonstrated that these proteins are O-glycosylated on serine or threonine residues and exported via an accessory secretion (aSec) system. In pathogens, these adhesins contribute to disease pathogenesis and represent therapeutic targets. Recently, the non-canonical aSec system has been identified in the genomes of gut microbes and characterization of their associated SRRPs is beginning to unfold, showing their role in mediating attachment and biofilm formation. Here we provide an update of the occurrence, structure, and function of SRRPs across bacteria, with emphasis on the molecular and biochemical properties of SRRPs from gut symbionts, particularly Lactobacilli. These emerging studies underscore the range of ligands recognized by these adhesins and the importance of SRRP glycosylation in the interaction of gut microbes with the host.
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Affiliation(s)
- Dimitrios Latousakis
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Donald A. MacKenzie
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Andrea Telatin
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
| | - Nathalie Juge
- The Gut Microbes and Health Institute Strategic Programme, Quadram Institute Bioscience, Norwich Research Park, Norwich, UK
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23
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Spencer C, Bensing BA, Mishra NN, Sullam PM. Membrane trafficking of the bacterial adhesin GspB and the accessory Sec transport machinery. J Biol Chem 2018; 294:1502-1515. [PMID: 30514759 DOI: 10.1074/jbc.ra118.005657] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/14/2018] [Indexed: 12/14/2022] Open
Abstract
The serine-rich repeat (SRR) glycoproteins of Gram-positive bacteria are large, cell wall-anchored adhesins that mediate binding to many host cells and proteins and are associated with bacterial virulence. SRR glycoproteins are exported to the cell surface by the accessory Sec (aSec) system comprising SecA2, SecY2, and 3-5 additional proteins (Asp1 to Asp5) that are required for substrate export. These adhesins typically have a 90-amino acid-long signal peptide containing an elongated N-region and a hydrophobic core. Previous studies of GspB (the SRR adhesin of Streptococcus gordonii) have shown that a glycine-rich motif in its hydrophobic core is essential for selective, aSec-mediated transport. However, the role of this extended N-region in transport is poorly understood. Here, using protein-lipid co-flotation assays and site-directed mutagenesis, we report that the N-region of the GspB signal peptide interacts with anionic lipids through electrostatic forces and that this interaction is necessary for GspB preprotein trafficking to lipid membranes. Moreover, we observed that protein-lipid binding is required for engagement of GspB with SecA2 and for aSec-mediated transport. We further found that SecA2 and Asp1 to Asp3 also localize selectively to liposomes that contain anionic lipids. These findings suggest that the GspB signal peptide electrostatically binds anionic lipids at the cell membrane, where it encounters SecA2. After SecA2 engagement with the signal peptide, Asp1 to Asp3 promote SecA2 engagement with the mature domain, which activates GspB translocation.
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Affiliation(s)
- Cierra Spencer
- Division of Infectious Diseases, San Francisco Veterans Affairs Medical Center, San Francisco, California 94121; Department of Medicine, University of California, San Francisco, California 94143
| | - Barbara A Bensing
- Division of Infectious Diseases, San Francisco Veterans Affairs Medical Center, San Francisco, California 94121; Department of Medicine, University of California, San Francisco, California 94143
| | - Nagendra N Mishra
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute, Torrance, California 90502; David Geffen School of Medicine, UCLA, Los Angeles, California 90095
| | - Paul M Sullam
- Division of Infectious Diseases, San Francisco Veterans Affairs Medical Center, San Francisco, California 94121; Department of Medicine, University of California, San Francisco, California 94143.
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Park OJ, Kim J, Kim HY, Kwon Y, Yun CH, Han SH. Streptococcus gordonii induces bone resorption by increasing osteoclast differentiation and reducing osteoblast differentiation. Microb Pathog 2018; 126:218-223. [PMID: 30414445 DOI: 10.1016/j.micpath.2018.11.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/26/2018] [Accepted: 11/02/2018] [Indexed: 01/18/2023]
Abstract
Streptococcus gordonii is commonly found in the periapical endodontic lesions of patients with apical periodontitis, a condition characterized by inflammation and periapical bone loss. Since bone metabolism is controlled by osteoclastic bone resorption and osteoblastic bone formation, we investigated the effects of S. gordonii on the differentiation and function of osteoclasts and osteoblasts. For the determination of bone resorption activity in vivo, collagen sheets soaked with heat-killed S. gordonii were implanted on mouse calvaria, and the calvarial bones were scanned by micro-computed tomography. Mouse bone marrow-derived macrophages (BMMs) were stimulated with M-CSF and RANKL for 2 days and then differentiated into osteoclasts in the presence or absence of heat-killed S. gordonii. Tartrate-resistant acid phosphatase staining was performed to determine osteoclast differentiation. Primary osteoblast precursors were differentiated into osteoblasts with ascorbic acid and β-glycerophosphate in the presence or absence of heat-killed S. gordonii. Alkaline phosphatase staining and alizarin red S staining were conducted to determine osteoblast differentiation. Western blotting was performed to examine the expression of transcription factors including c-Fos, NFATc1, and Runx2. Heat-killed S. gordonii induced bone destruction in a mouse calvarial implantation model. The differentiation of RANKL-primed BMMs into osteoclasts was enhanced in the presence of heat-killed S. gordonii. Heat-killed S. gordonii increased the expression of c-Fos and NFATc1, which are essential transcription factors for osteoclast differentiation. On the other hand, heat-killed S. gordonii inhibited osteoblast differentiation and reduced the expression of Runx2, an essential transcription factor for osteoblast differentiation. S. gordonii exerts bone resorptive activity by increasing osteoclast differentiation and reducing osteoblast differentiation, which may be involved in periapical bone resorption.
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Affiliation(s)
- Ok-Jin Park
- Department of Oral Microbiology and Immunology, DRI and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Jiseon Kim
- Department of Oral Microbiology and Immunology, DRI and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Hyun Young Kim
- Department of Oral Microbiology and Immunology, DRI and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Yeongkag Kwon
- Department of Oral Microbiology and Immunology, DRI and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 08826, Republic of Korea; Institute of Green Bio Science Technology, Seoul National University, Pyeongchang 25354, Republic of Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, DRI and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul 08826, Republic of Korea.
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SssP1, a Streptococcus suis Fimbria-Like Protein Transported by the SecY2/A2 System, Contributes to Bacterial Virulence. Appl Environ Microbiol 2018; 84:AEM.01385-18. [PMID: 30030221 DOI: 10.1128/aem.01385-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/10/2018] [Indexed: 12/20/2022] Open
Abstract
Streptococcus suis is an important Gram-positive pathogen in the swine industry and is an emerging zoonotic pathogen for humans. In our previous work, we found a virulent S. suis strain, CZ130302, belonging to a novel serotype, Chz, to be associated with acute meningitis in piglets. However, its underlying mechanisms of pathogenesis remain poorly understood. In this study, we sequenced and analyzed the complete genomes of three Chz serotype strains, including strain CZ130302 and two avirulent strains, HN136 and AH681. By genome comparison, we found two putative genomic islands (GIs) uniquely encoded in strain CZ130302 and designated them 50K GI and 58K GI. In mouse infection model, the deletion of 50K and 58K GIs caused 270-fold and 3-fold attenuation of virulence, respectively. Notably, we identified a complete SecY2/A2 system, coupled with its secretory protein SssP1 encoded in the 50K GI, which contributed to the pathogenicity of strain CZ130302. Immunogold electron microscopy and immunofluorescence analyses indicated that SssP1 could form fimbria-like structures that extend outward from the bacterial cell surface. The sssP1 mutation also attenuated bacterial adherence in human laryngeal epithelial (HEp-2) cells and human brain microvessel endothelial cells (HBMECs) compared with the wild type. Furthermore, we showed that two analogous Ig-like subdomains of SssP1 have sialic acid binding capacities. In conclusion, our results revealed that the 50K GI and the inside SecY2/A2 system gene cluster are related to the virulence of strain CZ130302, and we clarified a new S. suis pathogenesis mechanism mediated by the secretion protein SssP1.IMPORTANCE Streptococcus suis is an important zoonotic pathogen. Here, we managed to identify key factors to clarify the virulence of S. suis strain CZ130302 from a novel serotype, Chz. Notably, it was shown that a fimbria-like structure was significantly connected to the pathogenicity of the CZ130302 strain by comparative genomics analysis and animal infection assays. The mechanisms of how the CZ130302 strain constructs these fimbria-like structures in the cell surface by genes encoding and production transport were subsequently elucidated. Biosynthesis of the fimbria-like structure was achieved by the production of SssP1 glycoproteins, and its construction was dependent on the SecA2/Y2 secretion system. This study identified a visible fimbria-like protein, SssP1, participating in adhesion to host cells and contributing to the virulence in S. suis These findings will promote a better understanding of the pathogenesis of S. suis.
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26
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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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27
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Bensing BA, Li Q, Park D, Lebrilla CB, Sullam PM. Streptococcal Siglec-like adhesins recognize different subsets of human plasma glycoproteins: implications for infective endocarditis. Glycobiology 2018; 28:601-611. [PMID: 29796594 PMCID: PMC6054165 DOI: 10.1093/glycob/cwy052] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/21/2018] [Indexed: 12/23/2022] Open
Abstract
Streptococcus gordonii and Streptococcus sanguinis are typically found among the normal oral microbiota but can also cause infective endocarditis. These organisms express cell surface serine-rich repeat adhesins containing "Siglec-like" binding regions (SLBRs) that mediate attachment to α2-3-linked sialic acids on human glycoproteins. Two known receptors for the Siglec-like adhesins are the salivary mucin MG2/MUC7 and platelet GPIbα, and the interaction of streptococci with these targets may contribute to oral colonization and endocarditis, respectively. The SLBRs display a surprising diversity of preferences for defined glycans, ranging from highly selective to broader specificity. In this report, we characterize the glycoproteins in human plasma recognized by four SLBRs that prefer different α2-3 sialoglycan structures. We found that the SLBRs recognize a surprisingly small subset of plasma proteins that are extensively O-glycosylated. The preferred plasma protein ligands for a sialyl-T antigen-selective SLBR are proteoglycan 4 (lubricin) and inter-alpha-trypsin inhibitor heavy chain H4. Conversely, the preferred ligand for a 3'sialyllactosamine-selective SLBR is glycocalicin (the extracellular portion of platelet GPIbα). All four SLBRs recognize C1 inhibitor but detect distinctly different glycoforms of this key regulator of the complement and kallikrein protease cascades. The four plasma ligands have potential roles in thrombosis and inflammation, and each has been cited as a biomarker for one or more vascular or other diseases. The combined results suggest that the interaction of Siglec-like adhesins with different subsets of plasma glycoproteins could have a significant impact on the propensity of streptococci to establish endocardial infections.
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Affiliation(s)
- Barbara A Bensing
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, CA, USA
| | - Qiongyu Li
- Department of Chemistry, University of California, Davis, CA, USA
| | - Dayoung Park
- Department of Chemistry, University of California, Davis, CA, USA
| | | | - Paul M Sullam
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, CA, USA
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28
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Serine-Rich Repeat Adhesins Mediate Shear-Enhanced Streptococcal Binding to Platelets. Infect Immun 2018; 86:IAI.00160-18. [PMID: 29581195 DOI: 10.1128/iai.00160-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Indexed: 11/20/2022] Open
Abstract
The binding of bacteria to platelets is thought to be a central event in the pathogenesis of infective endocarditis. The serine-rich repeat (SRR) glycoproteins of viridans group streptococci have been shown to mediate platelet binding in vitro and to contribute to virulence in animal models. However, it is not known whether SRR adhesins can mediate streptococcal binding under the high fluidic shear stress conditions present on the endocardial surface. We found that three streptococcal SRR adhesins (GspB, Hsa, and SrpA) with differing structures and sialoglycan binding specificities nevertheless exhibited similar biomechanical properties. All three adhesins mediated shear-enhanced streptococcal binding to immobilized platelets through the platelet receptor GPIbα. Shear-enhanced adhesion was manifested in three ways. First, the number of circulating streptococci binding via SRR adhesins to immobilized platelet receptors peaked at 1 dyn/cm2 Second, bound streptococci switched from weak rolling to strong stationary adhesion as shear stress increased to 10 dyn/cm2 Third, while a few streptococci detached each time the flow was increased, the majority of streptococci bound to platelets remained firmly attached through 20 to 80 dyn/cm2 (shear levels typical of arteries and the endocardium). Thus, all three adhesins mediated shear-enhanced streptococcal binding to platelets under the flow conditions found in heart valves. The ability of the SRR adhesins to mediate shear-enhanced binding strongly suggests that they form catch bonds that are activated by tensile force and provides a mechanism for the selective targeting of bacteria to platelet receptors immobilized on the endocardial surface.
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29
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Abstract
Thrombocytopenia is common in patients with invasive bacterial infections. Bacteria can activate platelets, but it is unclear if this affects platelet count. The aim of this study was to examine whether bacteraemia with Staphylococcus aureus, which readily activate human platelets, was more likely to be complicated by thrombocytopenia than bacteraemia with Escherichia coli or Streptococcus pneumoniae with different abilities to activate platelets.We compared information from 600 adult patients with community-acquired bacteraemia with S. aureus (n = 140), E. coli (n = 420) and S. pneumoniae (n = 40) in Southern Sweden, 2012, linking information on positive blood cultures from microbiological databases and medical charts. The proportion of patients with thrombocytopenia (platelet count <150 × 109/ml) was calculated. Logistic regression was used to estimate the odds ratios (OR) for thrombocytopenia according to bacterial species adjusted for confounders.The proportion of thrombocytopenia was 29% in S. aureus, 28% in E. coli and 20% in S. pneumonia bacteraemia (P = 0.50), corresponding to an OR of 1.2 (95% confidence interval 0.7-1.9) for thrombocytopenia for S. aureus as compared with E. coli or S. pneumoniae, adjusted for confounders.This study indicates that platelet activation by bacteria is not a major causative mechanism in sepsis-associated thrombocytopenia.
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30
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Kim AR, Ahn KB, Kim HY, Seo HS, Kum KY, Yun C, Han SH. Streptococcus gordonii lipoproteins induce IL-8 in human periodontal ligament cells. Mol Immunol 2017; 91:218-224. [DOI: 10.1016/j.molimm.2017.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/06/2017] [Accepted: 09/18/2017] [Indexed: 12/21/2022]
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31
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Haworth JA, Mears RG, Jenkinson HF, Kerrigan SW, Nobbs AH. Oral hygiene as a risk factor in infective endocarditis. ACTA ACUST UNITED AC 2017. [DOI: 10.12968/denu.2017.44.9.877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jennifer A Haworth
- Academic Clinical Lecturer, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
| | - Richard G Mears
- General Dental Practitioner, Combe Road Dental Practice, 6 Combe Road, Portishead, BS20 6BJ and Clinical Teaching Fellow, Restorative Dentistry, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
| | - Howard F Jenkinson
- Professor of Oral Microbiology, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
| | - Steve W Kerrigan
- Senior Lecturer in Pharmacology, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - Angela H Nobbs
- Senior Lecturer in Oral Microbiology, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
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32
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Seepersaud R, Sychantha D, Bensing BA, Clarke AJ, Sullam PM. O-acetylation of the serine-rich repeat glycoprotein GspB is coordinated with accessory Sec transport. PLoS Pathog 2017; 13:e1006558. [PMID: 28827841 PMCID: PMC5578698 DOI: 10.1371/journal.ppat.1006558] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 08/31/2017] [Accepted: 07/28/2017] [Indexed: 11/17/2022] Open
Abstract
The serine-rich repeat (SRR) glycoproteins are a family of adhesins found in many Gram-positive bacteria. Expression of the SRR adhesins has been linked to virulence for a variety of infections, including streptococcal endocarditis. The SRR preproteins undergo intracellular glycosylation, followed by export via the accessory Sec (aSec) system. This specialized transporter is comprised of SecA2, SecY2 and three to five accessory Sec proteins (Asps) that are required for export. Although the post-translational modification and transport of the SRR adhesins have been viewed as distinct processes, we found that Asp2 of Streptococcus gordonii also has an important role in modifying the SRR adhesin GspB. Biochemical analysis and mass spectrometry indicate that Asp2 is an acetyltransferase that modifies N-acetylglucosamine (GlcNAc) moieties on the SRR domains of GspB. Targeted mutations of the predicted Asp2 catalytic domain had no effect on transport, but abolished acetylation. Acetylated forms of GspB were only detected when the protein was exported via the aSec system, but not when transport was abolished by secA2 deletion. In addition, GspB variants rerouted to export via the canonical Sec pathway also lacked O-acetylation, demonstrating that this modification is specific to export via the aSec system. Streptococci expressing GspB lacking O-acetylated GlcNAc were significantly reduced in their ability bind to human platelets in vitro, an interaction that has been strongly linked to virulence in the setting of endocarditis. These results demonstrate that Asp2 is a bifunctional protein involved in both the post-translational modification and transport of SRR glycoproteins. In addition, these findings indicate that these processes are coordinated during the biogenesis of SRR glycoproteins, such that the adhesin is optimally modified for binding. This requirement for the coupling of modification and export may explain the co-evolution of the SRR glycoproteins with their specialized glycan modifying and export systems.
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Affiliation(s)
- Ravin Seepersaud
- San Francisco Veteran Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA, United States of America
| | - David Sychantha
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Barbara A Bensing
- San Francisco Veteran Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA, United States of America
| | - Anthony J Clarke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Paul M Sullam
- San Francisco Veteran Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA, United States of America
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Couvigny B, Lapaque N, Rigottier-Gois L, Guillot A, Chat S, Meylheuc T, Kulakauskas S, Rohde M, Mistou MY, Renault P, Doré J, Briandet R, Serror P, Guédon E. Three glycosylated serine-rich repeat proteins play a pivotal role in adhesion and colonization of the pioneer commensal bacterium,Streptococcus salivarius. Environ Microbiol 2017; 19:3579-3594. [DOI: 10.1111/1462-2920.13853] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 01/25/2023]
Affiliation(s)
- Benoit Couvigny
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Nicolas Lapaque
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Lionel Rigottier-Gois
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Alain Guillot
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Sophie Chat
- INRA, Plateforme MIMA2; Jouy-en-josas France
| | - Thierry Meylheuc
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
- INRA, Plateforme MIMA2; Jouy-en-josas France
| | - Saulius Kulakauskas
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Manfred Rohde
- HZI, Helmholtz Centre for Infection Research; Braunschweig Germany
| | - Michel-Yves Mistou
- Laboratory for Food Safety; Université Paris-Est, ANSES; Maisons-Alfort France
| | - Pierre Renault
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Joel Doré
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Romain Briandet
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Pascale Serror
- MICALIS Institute, INRA, AgroParisTech; Université Paris-Saclay; Jouy-en-Josas France
| | - Eric Guédon
- STLO, UMR1253, INRA, Agrocampus Ouest; Rennes France
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Ko EB, Kim SK, Seo HS, Yun CH, Han SH. Serine-Rich Repeat Adhesins Contribute to Streptococcus gordonii-Induced Maturation of Human Dendritic Cells. Front Microbiol 2017; 8:523. [PMID: 28408901 PMCID: PMC5374164 DOI: 10.3389/fmicb.2017.00523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 03/13/2017] [Indexed: 01/27/2023] Open
Abstract
Dendritic cells (DCs) play a pivotal role in the induction of immunity by recognition, capture, process, and presentation of antigens from infectious microbes. Streptococcus gordonii is able to cause life-threatening systemic diseases such as infective endocarditis. Serine-rich repeat (SRR) glycoproteins of S. gordonii are sialic acid-binding adhesins mediating the bacterial adherence to the host and the development of infective endocarditis. Thus, the SRR adhesins are potentially involved in the bacterial adherence to DCs and the maturation and activation of DCs required for the induction of immunity to S. gordonii. Here, we investigated the phenotypic and functional changes of human monocyte-derived DCs treated with wild-type S. gordonii or the SRR adhesin-deficient mutant. The mutant poorly bound to DCs and only weakly increased the expression of CD83, CD86, MHC class II, and PD-L1 on DCs compared with the wild-type. In addition, the mutant induced lower levels of TNF-α, IL-6, and IL-12 than the wild-type in DCs. When DCs sensitized with the mutant were co-cultured with autologous T cells, they induced weaker proliferation and activation of T cells than DCs stimulated with the wild-type. Blockade of SRR adhesin with 3′-sialyllactose markedly reduced S. gordonii binding and internalization, causing attenuation of the bacterial immunostimulatory potency in DC maturation. Collectively, our results suggest that SRR adhesins of S. gordonii are important for maturation and activation of DCs.
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Affiliation(s)
- Eun Byeol Ko
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National UniversitySeoul, South Korea
| | - Sun Kyung Kim
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National UniversitySeoul, South Korea
| | - Ho Seong Seo
- Biotechnology Research Division, Korea Atomic Energy Research InstituteJeongeup, South Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National UniversitySeoul, South Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National UniversitySeoul, South Korea
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Streptococcus oralis Neuraminidase Modulates Adherence to Multiple Carbohydrates on Platelets. Infect Immun 2017; 85:IAI.00774-16. [PMID: 27993975 DOI: 10.1128/iai.00774-16] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/15/2016] [Indexed: 11/20/2022] Open
Abstract
Adherence to host surfaces is often mediated by bacterial binding to surface carbohydrates. Although it is widely appreciated that some bacterial species express glycosidases, previous studies have not considered whether bacteria bind to multiple carbohydrates within host glycans as they are modified by bacterial glycosidases. Streptococcus oralis is a leading cause of subacute infective endocarditis. Binding to platelets is a critical step in disease; however, the mechanisms utilized by S. oralis remain largely undefined. Studies revealed that S. oralis, like Streptococcus gordonii and Streptococcus sanguinis, binds platelets via terminal sialic acid. However, unlike those organisms, S. oralis produces a neuraminidase, NanA, which cleaves terminal sialic acid. Further studies revealed that following NanA-dependent removal of terminal sialic acid, S. oralis bound exposed β-1,4-linked galactose. Adherence to both these carbohydrates required Fap1, the S. oralis member of the serine-rich repeat protein (SRRP) family of adhesins. Mutation of a conserved residue required for sialic acid binding by other SRRPs significantly reduced platelet binding, supporting the hypothesis that Fap1 binds this carbohydrate. The mechanism by which Fap1 contributes to β-1,4-linked galactose binding remains to be defined; however, binding may occur via additional domains of unknown function within the nonrepeat region, one of which shares some similarity with a carbohydrate binding module. This study is the first demonstration that an SRRP is required to bind β-1,4-linked galactose and the first time that one of these adhesins has been shown to be required for binding of multiple glycan receptors.
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Bleiziffer I, Eikmeier J, Pohlentz G, McAulay K, Xia G, Hussain M, Peschel A, Foster S, Peters G, Heilmann C. The Plasmin-Sensitive Protein Pls in Methicillin-Resistant Staphylococcus aureus (MRSA) Is a Glycoprotein. PLoS Pathog 2017; 13:e1006110. [PMID: 28081265 PMCID: PMC5230774 DOI: 10.1371/journal.ppat.1006110] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 12/02/2016] [Indexed: 01/16/2023] Open
Abstract
Most bacterial glycoproteins identified to date are virulence factors of pathogenic bacteria, i.e. adhesins and invasins. However, the impact of protein glycosylation on the major human pathogen Staphylococcus aureus remains incompletely understood. To study protein glycosylation in staphylococci, we analyzed lysostaphin lysates of methicillin-resistant Staphylococcus aureus (MRSA) strains by SDS-PAGE and subsequent periodic acid-Schiff’s staining. We detected four (>300, ∼250, ∼165, and ∼120 kDa) and two (>300 and ∼175 kDa) glycosylated surface proteins with strain COL and strain 1061, respectively. The ∼250, ∼165, and ∼175 kDa proteins were identified as plasmin-sensitive protein (Pls) by mass spectrometry. Previously, Pls has been demonstrated to be a virulence factor in a mouse septic arthritis model. The pls gene is encoded by the staphylococcal cassette chromosome (SCC)mec type I in MRSA that also encodes the methicillin resistance-conferring mecA and further genes. In a search for glycosyltransferases, we identified two open reading frames encoded downstream of pls on the SCCmec element, which we termed gtfC and gtfD. Expression and deletion analysis revealed that both gtfC and gtfD mediate glycosylation of Pls. Additionally, the recently reported glycosyltransferases SdgA and SdgB are involved in Pls glycosylation. Glycosylation occurs at serine residues in the Pls SD-repeat region and modifying carbohydrates are N-acetylhexosaminyl residues. Functional characterization revealed that Pls can confer increased biofilm formation, which seems to involve two distinct mechanisms. The first mechanism depends on glycosylation of the SD-repeat region by GtfC/GtfD and probably also involves eDNA, while the second seems to be independent of glycosylation as well as eDNA and may involve the centrally located G5 domains. Other previously known Pls properties are not related to the sugar modifications. In conclusion, Pls is a glycoprotein and Pls glycosyl residues can stimulate biofilm formation. Thus, sugar modifications may represent promising new targets for novel therapeutic or prophylactic measures against life-threatening S. aureus infections. Staphylococcus aureus is a serious pathogen that causes life-threatening infections due to its ability to attach to surfaces, form biofilms, and persist inside the host. One of previously identified virulence factors in S. aureus pathogenesis is the plasmin-sensitive surface protein Pls. We here identified Pls as a posttranslationally modified glycoprotein and characterized the domain within Pls that becomes glycosylated as well as the modifying sugars. Moreover, we found that the glycosyltransferases GtfC and GtfD carry out the glycosylation reactions. In a search for a role for the modifying sugars, we found that Pls can stimulate biofilm formation apparently via two distinct mechanisms, one being dependent on glycosylation by GtfC and GtfD the other being independent of glycosylation as well as eDNA. Moreover, we found that none of the already known Pls functions is mediated by the sugar moieties. Thus, we conclude that GtfC/GtfD-glycosylated Pls may contribute to MRSA pathogenicity via stimulation of biofilm formation and may serve as future target to combat or prevent infections with this serious pathogen.
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Affiliation(s)
- Isabelle Bleiziffer
- Institute of Medical Microbiology, University of Münster, Münster, Germany
- Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany
| | - Julian Eikmeier
- Institute of Medical Microbiology, University of Münster, Münster, Germany
- Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany
| | | | - Kathryn McAulay
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Guoqing Xia
- Division of Infection, Immunity and Respiratory Medicine, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Muzaffar Hussain
- Institute of Medical Microbiology, University of Münster, Münster, Germany
| | - Andreas Peschel
- Interfaculty Institute of Microbiology and Infection Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, University of Tübingen, Tübingen, Germany
| | - Simon Foster
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom
| | - Georg Peters
- Institute of Medical Microbiology, University of Münster, Münster, Germany
- Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany
- Cluster of Excellence EXC 1003, Cells in Motion, University of Münster, Münster, Germany
| | - Christine Heilmann
- Institute of Medical Microbiology, University of Münster, Münster, Germany
- Interdisciplinary Center for Clinical Research (IZKF), University of Münster, Münster, Germany
- * E-mail:
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Haworth JA, Jenkinson HF, Petersen HJ, Back CR, Brittan JL, Kerrigan SW, Nobbs AH. Concerted functions of Streptococcus gordonii surface proteins PadA and Hsa mediate activation of human platelets and interactions with extracellular matrix. Cell Microbiol 2017; 19:e12667. [PMID: 27616700 PMCID: PMC5574023 DOI: 10.1111/cmi.12667] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 09/07/2016] [Indexed: 12/17/2022]
Abstract
A range of Streptococcus bacteria are able to interact with blood platelets to form a thrombus (clot). Streptococcus gordonii is ubiquitous within the human oral cavity and amongst the common pathogens isolated from subjects with infective endocarditis. Two cell surface proteins, Hsa and Platelet adherence protein A (PadA), in S. gordonii mediate adherence and activation of platelets. In this study, we demonstrate that PadA binds activated platelets and that an NGR (Asparagine-Glycine-Arginine) motif within a 657 amino acid residue N-terminal fragment of PadA is responsible for this, together with two other integrin-like recognition motifs RGT and AGD. PadA also acts in concert with Hsa to mediate binding of S. gordonii to cellular fibronectin and vitronectin, and to promote formation of biofilms. Evidence is presented that PadA and Hsa are each reliant on the other's active presentation on the bacterial cell surface, suggesting cooperativity in functions impacting both colonization and pathogenesis.
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Affiliation(s)
| | | | | | | | - Jane L. Brittan
- School of Oral and Dental SciencesUniversity of BristolBristolUK
| | - Steve W. Kerrigan
- Cardiovascular Infection GroupRoyal College of Surgeons in IrelandDublin 2Ireland
| | - Angela H. Nobbs
- School of Oral and Dental SciencesUniversity of BristolBristolUK
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Abstract
Simple and complex carbohydrates (glycans) have long been known to play major metabolic, structural and physical roles in biological systems. Targeted microbial binding to host glycans has also been studied for decades. But such biological roles can only explain some of the remarkable complexity and organismal diversity of glycans in nature. Reviewing the subject about two decades ago, one could find very few clear-cut instances of glycan-recognition-specific biological roles of glycans that were of intrinsic value to the organism expressing them. In striking contrast there is now a profusion of examples, such that this updated review cannot be comprehensive. Instead, a historical overview is presented, broad principles outlined and a few examples cited, representing diverse types of roles, mediated by various glycan classes, in different evolutionary lineages. What remains unchanged is the fact that while all theories regarding biological roles of glycans are supported by compelling evidence, exceptions to each can be found. In retrospect, this is not surprising. Complex and diverse glycans appear to be ubiquitous to all cells in nature, and essential to all life forms. Thus, >3 billion years of evolution consistently generated organisms that use these molecules for many key biological roles, even while sometimes coopting them for minor functions. In this respect, glycans are no different from other major macromolecular building blocks of life (nucleic acids, proteins and lipids), simply more rapidly evolving and complex. It is time for the diverse functional roles of glycans to be fully incorporated into the mainstream of biological sciences.
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Affiliation(s)
- Ajit Varki
- Departments of Medicine and Cellular & Molecular Medicine, Glycobiology Research and Training Center, University of California at San Diego, La Jolla, CA 92093-0687, USA
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Antibodies Targeting Hsa and PadA Prevent Platelet Aggregation and Protect Rats against Experimental Endocarditis Induced by Streptococcus gordonii. Infect Immun 2016; 84:3557-3563. [PMID: 27736784 DOI: 10.1128/iai.00810-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 09/22/2016] [Indexed: 01/24/2023] Open
Abstract
Streptococcus gordonii and related species of oral viridans group streptococci (VGS) are common etiological agents of infective endocarditis (IE). We explored vaccination as a strategy to prevent VGS-IE, using a novel antigen-presenting system based on non-genetically modified Lactococcus lactis displaying vaccinogens on its surface. Hsa and PadA are surface-located S. gordonii proteins implicated in platelet adhesion and aggregation, which are key steps in the pathogenesis of IE. This function makes them ideal targets for vaccination against VGS-IE. In the present study, we report the use of nonliving L. lactis displaying at its surface the N-terminal region of Hsa or PadA by means of the cell wall binding domain of Lactobacillus casei A2 phage lysine LysA2 (Hsa-LysA2 and PadA-LysA2, respectively) and investigation of their ability to elicit antibodies in rats and to protect them from S. gordonii experimental IE. Immunized and control animals with catheter-induced sterile aortic valve vegetations were inoculated with 106 CFU of S. gordonii The presence of IE was evaluated 24 h later. Immunization of rats with L. lactis Hsa-LysA2, L. lactis PadA-LysA2, or both protected 6/11 (55%), 6/11 (55%), and 11/12 (91%) animals, respectively, from S. gordonii IE (P < 0.05 versus controls). Protection correlated with the induction of high levels of functional antibodies against both Hsa and PadA that delayed or totally inhibited platelet aggregation by S. gordonii These results support the value of L. lactis as a system for antigen delivery and of Hsa and PadA as promising candidates for a vaccine against VGS-IE.
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40
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Kim AR, Ahn KB, Kim HY, Seo HS, Yun CH, Han SH. Serine-rich Repeat Adhesin Gordonii Surface Protein B is Important for Streptococcus gordonii Biofilm Formation. J Endod 2016; 42:1767-1772. [PMID: 27769678 DOI: 10.1016/j.joen.2016.08.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2016] [Revised: 08/15/2016] [Accepted: 08/15/2016] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Streptococcus gordonii is a predominant member of the oral microflora and has been isolated from root canals of teeth with refractory apical periodontitis. Biofilm formation is important for various dental diseases, and S. gordonii is involved in dental biofilm formation as an early colonizer. Although serine-rich repeat (SRR) adhesins of S. gordonii such as gordonii surface protein B (GspB) are associated with bacterial colonization, the role of GspB in biofilm formation is not clearly understood. In the present study, we investigated the effect of S. gordonii GspB on biofilm formation using wild-type and GspB-deficient mutant S. gordonii strains. METHODS Confocal microscopy and crystal violet assay were used to determine biofilm formation. Bacterial growth was examined by measuring optical density with spectrometry. Bacterial adherence and biofilm on the culture plate and human dentin slices were visualized with a scanning electron microscope. RESULTS The GspB-deficient S. gordonii mutant strain was less potent than the wild-type strain in biofilm formation. Of note, there was no difference in the bacterial growth rate between the mutant and wild-type strains. Differences in biofilm-forming ability between the wild-type and mutant strains were more distinct in the sucrose-supplemented media. Furthermore, the GspB-deficient mutant exhibited attenuated formation of aggregates on the surface of the culture plate and human dentin slices. CONCLUSIONS These results suggest that GspB is important for S. gordonii biofilm formation, which may contribute to the development of dental biofilm-associated diseases.
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Affiliation(s)
- A Reum Kim
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Ki Bum Ahn
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Hyun Young Kim
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Ho Seong Seo
- Radiation Biotechnology Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Republic of Korea
| | - Cheol-Heui Yun
- Department of Agricultural Biotechnology and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Seung Hyun Han
- Department of Oral Microbiology and Immunology, DRI, and BK21 Plus Program, School of Dentistry, Seoul National University, Seoul, Republic of Korea.
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Abstract
Infective endocarditis (IE) is a rare, life-threatening disease that has long-lasting effects even among patients who survive and are cured. IE disproportionately affects those with underlying structural heart disease and is increasingly associated with health care contact, particularly in patients who have intravascular prosthetic material. In the setting of bacteraemia with a pathogenic organism, an infected vegetation may form as the end result of complex interactions between invading microorganisms and the host immune system. Once established, IE can involve almost any organ system in the body. The diagnosis of IE may be difficult to establish and a strategy that combines clinical, microbiological and echocardiography results has been codified in the modified Duke criteria. In cases of blood culture-negative IE, the diagnosis may be especially challenging, and novel microbiological and imaging techniques have been developed to establish its presence. Once diagnosed, IE is best managed by a multidisciplinary team with expertise in infectious diseases, cardiology and cardiac surgery. Antibiotic prophylaxis for the prevention of IE remains controversial. Efforts to develop a vaccine that targets common bacterial causes of IE are ongoing, but have not yet yielded a commercially available product.
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Affiliation(s)
- Thomas L Holland
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Room 185 Hanes Building, 315 Trent Drive, Durham, North Carolina 27710, USA
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Larry M Baddour
- Department of Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Arnold S Bayer
- Department of Medicine, David Geffen School of Medicine at UCLA, Torrance, California, USA
| | - Bruno Hoen
- Department of Infectious Diseases, University Hospital of Pointe-Pitre, Pointe-Pitre, France
| | - Jose M Miro
- Infectious Diseases Service, Hospital Clinic - IDIBAPS, University of Barcelona, Barcelona, Spain
| | - Vance G Fowler
- Department of Medicine, Division of Infectious Diseases, Duke University Medical Center, Room 185 Hanes Building, 315 Trent Drive, Durham, North Carolina 27710, USA
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina, USA
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Willenborg J, Goethe R. Metabolic traits of pathogenic streptococci. FEBS Lett 2016; 590:3905-3919. [PMID: 27442496 DOI: 10.1002/1873-3468.12317] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/12/2016] [Accepted: 07/18/2016] [Indexed: 12/13/2022]
Abstract
Invasive and noninvasive diseases caused by facultative pathogenic streptococci depend on their equipment with virulence factors and on their ability to sense and adapt to changing nutrients in different host environments. The knowledge of the principal metabolic mechanisms which allow these bacteria to recognize and utilize nutrients in host habitats is a prerequisite for our understanding of streptococcal pathogenicity and the development of novel control strategies. This review aims to summarize and compare the central carbohydrate metabolic and amino acid biosynthetic pathways of a selected group of streptococcal species, all belonging to the naso-oropharyngeal microbiome in humans and/or animals. We also discuss the urgent need of comprehensive metabolomics approaches for a better understanding of the streptococcal metabolism during host-pathogen interaction.
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Affiliation(s)
- Jörg Willenborg
- Institute for Microbiology, University of Veterinary Medicine Hannover, Germany
| | - Ralph Goethe
- Institute for Microbiology, University of Veterinary Medicine Hannover, Germany
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Bensing BA, Khedri Z, Deng L, Yu H, Prakobphol A, Fisher SJ, Chen X, Iverson TM, Varki A, Sullam PM. Novel aspects of sialoglycan recognition by the Siglec-like domains of streptococcal SRR glycoproteins. Glycobiology 2016; 26:1222-1234. [PMID: 27037304 DOI: 10.1093/glycob/cww042] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 03/23/2016] [Accepted: 03/25/2016] [Indexed: 12/15/2022] Open
Abstract
Serine-rich repeat glycoproteins are adhesins expressed by commensal and pathogenic Gram-positive bacteria. A subset of these adhesins, expressed by oral streptococci, binds sialylated glycans decorating human salivary mucin MG2/MUC7, and platelet glycoprotein GPIb. Specific sialoglycan targets were previously identified for the ligand-binding regions (BRs) of GspB and Hsa, two serine-rich repeat glycoproteins expressed by Streptococcus gordonii While GspB selectively binds sialyl-T antigen, Hsa displays broader specificity. Here we examine the binding properties of four additional BRs from Streptococcus sanguinis or Streptococcus mitis and characterize the molecular determinants of ligand selectivity and affinity. Each BR has two domains that are essential for sialoglycan binding by GspB. One domain is structurally similar to the glycan-binding module of mammalian Siglecs (sialic acid-binding immunoglobulin-like lectins), including an arginine residue that is critical for glycan recognition, and that resides within a novel, conserved YTRY motif. Despite low sequence similarity to GspB, one of the BRs selectively binds sialyl-T antigen. Although the other three BRs are highly similar to Hsa, each displayed a unique ligand repertoire, including differential recognition of sialyl Lewis antigens and sulfated glycans. These differences in glycan selectivity were closely associated with differential binding to salivary and platelet glycoproteins. Specificity of sialoglycan adherence is likely an evolving trait that may influence the propensity of streptococci expressing Siglec-like adhesins to cause infective endocarditis.
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Affiliation(s)
- Barbara A Bensing
- Department of Medicine, The San Francisco Veterans Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA 94121, USA
| | - Zahra Khedri
- The Glycobiology Research and Training Center, and the Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Lingquan Deng
- The Glycobiology Research and Training Center, and the Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Hai Yu
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Akraporn Prakobphol
- Department of Obstetrics, Gynecology and Reproductive Sciences, The University of California, San Francisco, San Francisco, CA 94143, USA
| | - Susan J Fisher
- Department of Obstetrics, Gynecology and Reproductive Sciences, The University of California, San Francisco, San Francisco, CA 94143, USA
| | - Xi Chen
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Tina M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, TN 27232, USA
| | - Ajit Varki
- The Glycobiology Research and Training Center, and the Department of Cellular and Molecular Medicine, University of California, San Diego, San Diego, CA 92093, USA
| | - Paul M Sullam
- Department of Medicine, The San Francisco Veterans Affairs Medical Center, and the University of California, San Francisco, San Francisco, CA 94121, USA
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Abstract
There is an ongoing race between bacterial evolution and medical advances. Pathogens have the advantages of short generation times and horizontal gene transfer that enable rapid adaptation to new host environments and therapeutics that currently outpaces clinical research. Antibiotic resistance, the growing impact of nosocomial infections, cancer-causing bacteria, the risk of zoonosis, and the possibility of biowarfare all emphasize the increasingly urgent need for medical research focussed on bacterial pathogens. Bacterial glycoproteins are promising targets for alternative therapeutic intervention since they are often surface exposed, involved in host-pathogen interactions, required for virulence, and contain distinctive glycan structures. The potential exists to exploit these unique structures to improve clinical prevention, diagnosis, and treatment strategies. Translation of the potential in this field to actual clinical impact is an exciting prospect for fighting infectious diseases.
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Affiliation(s)
- Kelly M Fulton
- a Human Health Therapeutics Portfolio , National Research Council Canada , Ottawa , Canada
| | - Jeffrey C Smith
- b Department of Chemistry and Institute of Biochemistry , Carleton University , Ottawa , Canada
| | - Susan M Twine
- a Human Health Therapeutics Portfolio , National Research Council Canada , Ottawa , Canada
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Bensing BA, Loukachevitch LV, McCulloch KM, Yu H, Vann KR, Wawrzak Z, Anderson S, Chen X, Sullam PM, Iverson TM. Structural Basis for Sialoglycan Binding by the Streptococcus sanguinis SrpA Adhesin. J Biol Chem 2016; 291:7230-40. [PMID: 26833566 DOI: 10.1074/jbc.m115.701425] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Indexed: 11/06/2022] Open
Abstract
Streptococcus sanguinisis a leading cause of infective endocarditis, a life-threatening infection of the cardiovascular system. An important interaction in the pathogenesis of infective endocarditis is attachment of the organisms to host platelets.S. sanguinisexpresses a serine-rich repeat adhesin, SrpA, similar in sequence to platelet-binding adhesins associated with increased virulence in this disease. In this study, we determined the first crystal structure of the putative binding region of SrpA (SrpABR) both unliganded and in complex with a synthetic disaccharide ligand at 1.8 and 2.0 Å resolution, respectively. We identified a conserved Thr-Arg motif that orients the sialic acid moiety and is required for binding to platelet monolayers. Furthermore, we propose that sequence insertions in closely related family members contribute to the modulation of structural and functional properties, including the quaternary structure, the tertiary structure, and the ligand-binding site.
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Affiliation(s)
- Barbara A Bensing
- From the Division of Infectious Diseases, Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121
| | | | | | - Hai Yu
- the Department of Chemistry, University of California, Davis, California 95616, and
| | | | - Zdzislaw Wawrzak
- Life Sciences Collaborative Access Team, Synchrotron Research Center, Northwestern University, Argonne, Illinois 60439
| | - Spencer Anderson
- Life Sciences Collaborative Access Team, Synchrotron Research Center, Northwestern University, Argonne, Illinois 60439
| | - Xi Chen
- the Department of Chemistry, University of California, Davis, California 95616, and
| | - Paul M Sullam
- From the Division of Infectious Diseases, Veterans Affairs Medical Center, Department of Medicine, University of California, San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121
| | - T M Iverson
- the Departments of Pharmacology and Biochemistry, Center for Structural Biology, and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232,
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Structural Similarities and Differences between Two Functionally Distinct SecA Proteins, Mycobacterium tuberculosis SecA1 and SecA2. J Bacteriol 2015; 198:720-30. [PMID: 26668263 DOI: 10.1128/jb.00696-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 12/01/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED While SecA is the ATPase component of the major bacterial secretory (Sec) system, mycobacteria and some Gram-positive pathogens have a second paralog, SecA2. In bacteria with two SecA paralogs, each SecA is functionally distinct, and they cannot compensate for one another. Compared to SecA1, SecA2 exports a distinct and smaller set of substrates, some of which have roles in virulence. In the mycobacterial system, some SecA2-dependent substrates lack a signal peptide, while others contain a signal peptide but possess features in the mature protein that necessitate a role for SecA2 in their export. It is unclear how SecA2 functions in protein export, and one open question is whether SecA2 works with the canonical SecYEG channel to export proteins. In this study, we report the structure of Mycobacterium tuberculosis SecA2 (MtbSecA2), which is the first structure of any SecA2 protein. A high level of structural similarity is observed between SecA2 and SecA1. The major structural difference is the absence of the helical wing domain, which is likely to play a role in how MtbSecA2 recognizes its unique substrates. Importantly, structural features critical to the interaction between SecA1 and SecYEG are preserved in SecA2. Furthermore, suppressor mutations of a dominant-negative secA2 mutant map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG or the translocating polypeptide substrate. These results support a model in which the mycobacterial SecA2 works with SecYEG. IMPORTANCE SecA2 is a paralog of SecA1, which is the ATPase of the canonical bacterial Sec secretion system. SecA2 has a nonredundant function with SecA1, and SecA2 exports a distinct and smaller set of substrates than SecA1. This work reports the crystal structure of SecA2 of Mycobacterium tuberculosis (the first SecA2 structure reported for any organism). Many of the structural features of SecA1 are conserved in the SecA2 structure, including putative contacts with the SecYEG channel. Several structural differences are also identified that could relate to the unique function and selectivity of SecA2. Suppressor mutations of a secA2 mutant map to the surface of SecA2 and help identify functional regions of SecA2 that may promote interactions with SecYEG.
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Generic determinants of Streptococcus colonization and infection. INFECTION GENETICS AND EVOLUTION 2015; 33:361-70. [DOI: 10.1016/j.meegid.2014.09.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Revised: 09/10/2014] [Accepted: 09/14/2014] [Indexed: 11/20/2022]
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Lewis NE, Brady LJ. Breaking the bacterial protein targeting and translocation model: oral organisms as a case in point. Mol Oral Microbiol 2014; 30:186-97. [PMID: 25400073 DOI: 10.1111/omi.12088] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2014] [Indexed: 12/19/2022]
Abstract
Insights into the membrane biogenesis of oral and throat bacteria have highlighted key differences in protein localization by the general secretion pathway compared with the well-studied Escherichia coli model system. These intriguing novelties have advanced our understanding of both how these microorganisms have adapted to survive and cause disease in the oral cavity, and the field of protein translocation as a whole. This review focuses on findings that highlight where oral bacteria differ from the E. coli paradigm, why these differences are biologically important, and what questions remain about the differences in pathway function. The majority of insight into protein translocation in microbes of the oral cavity has come from streptococcal species, which will be the main topic of this review. However, other bacteria will be discussed when relevant. An overview of the E. coli model of protein targeting and translocation is provided for comparison.
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Affiliation(s)
- N E Lewis
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville, FL, USA
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Oral streptococci utilize a Siglec-like domain of serine-rich repeat adhesins to preferentially target platelet sialoglycans in human blood. PLoS Pathog 2014; 10:e1004540. [PMID: 25474103 PMCID: PMC4256463 DOI: 10.1371/journal.ppat.1004540] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 10/27/2014] [Indexed: 12/19/2022] Open
Abstract
Damaged cardiac valves attract blood-borne bacteria, and infective endocarditis is often caused by viridans group streptococci. While such bacteria use multiple adhesins to maintain their normal oral commensal state, recognition of platelet sialoglycans provides an intermediary for binding to damaged valvular endocardium. We use a customized sialoglycan microarray to explore the varied binding properties of phylogenetically related serine-rich repeat adhesins, the GspB, Hsa, and SrpA homologs from Streptococcus gordonii and Streptococcus sanguinis species, which belong to a highly conserved family of glycoproteins that contribute to virulence for a broad range of Gram-positive pathogens. Binding profiles of recombinant soluble homologs containing novel sialic acid-recognizing Siglec-like domains correlate well with binding of corresponding whole bacteria to arrays. These bacteria show multiple modes of glycan, protein, or divalent cation-dependent binding to synthetic glycoconjugates and isolated glycoproteins in vitro. However, endogenous asialoglycan-recognizing clearance receptors are known to ensure that only fully sialylated glycans dominate in the endovascular system, wherein we find these particular streptococci become primarily dependent on their Siglec-like adhesins for glycan-mediated recognition events. Remarkably, despite an excess of alternate sialoglycan ligands in cellular and soluble blood components, these adhesins selectively target intact bacteria to sialylated ligands on platelets, within human whole blood. These preferred interactions are inhibited by corresponding recombinant soluble adhesins, which also preferentially recognize platelets. Our data indicate that circulating platelets may act as inadvertent Trojan horse carriers of oral streptococci to the site of damaged endocardium, and provide an explanation why it is that among innumerable microbes that gain occasional access to the bloodstream, certain viridans group streptococci have a selective advantage in colonizing damaged cardiac valves and cause infective endocarditis. Bacterial infective endocarditis remains a disease with considerable morbidity and mortality. Of the numerous bacteria that can enter the bloodstream, certain oral commensal viridans group streptococci are among the major causative organisms of endocarditis. However, mechanisms underlying this selectivity are incompletely understood. Interactions between adhesins of such bacteria and human platelet sialoglycans are believed to play an important role in this selectivity, by facilitating bacterial adherence to damaged heart valves. Nevertheless, the molecular requirements for these interactions are not fully explored. Particularly, it is unclear whether selective targeting of platelets by these bacteria actually occurs in fluid human whole blood, an environment where numerous potential sialoglycan competitors exist. In the present work, we have addressed these important issues. We characterize in detail the glycan-binding spectra of a series of serine-rich repeat adhesins of oral streptococci. For the first time, we demonstrate that oral streptococci can indeed selectively target platelets in whole human blood. As a proof of concept, we also show that soluble recombinant bacterial adhesin binding region proteins can block the preferred platelet-bacterial interactions in whole blood. The knowledge gained from this study may help the development of novel preventive or therapeutic approaches against infective endocarditis.
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Chaze T, Guillot A, Valot B, Langella O, Chamot-Rooke J, Di Guilmi AM, Trieu-Cuot P, Dramsi S, Mistou MY. O-Glycosylation of the N-terminal region of the serine-rich adhesin Srr1 of Streptococcus agalactiae explored by mass spectrometry. Mol Cell Proteomics 2014; 13:2168-82. [PMID: 24797265 DOI: 10.1074/mcp.m114.038075] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Serine-rich (Srr) proteins exposed at the surface of Gram-positive bacteria are a family of adhesins that contribute to the virulence of pathogenic staphylococci and streptococci. Lectin-binding experiments have previously shown that Srr proteins are heavily glycosylated. We report here the first mass-spectrometry analysis of the glycosylation of Streptococcus agalactiae Srr1. After Srr1 enrichment and trypsin digestion, potential glycopeptides were identified in collision induced dissociation spectra using X! Tandem. The approach was then refined using higher energy collisional dissociation fragmentation which led to the simultaneous loss of sugar residues, production of diagnostic oxonium ions and backbone fragmentation for glycopeptides. This feature was exploited in a new open source software tool (SpectrumFinder) developed for this work. By combining these approaches, 27 glycopeptides corresponding to six different segments of the N-terminal region of Srr1 [93-639] were identified. Our data unambiguously indicate that the same protein residue can be modified with different glycan combinations including N-acetylhexosamine, hexose, and a novel modification that was identified as O-acetylated-N-acetylhexosamine. Lectin binding and monosaccharide composition analysis strongly suggested that HexNAc and Hex correspond to N-acetylglucosamine and glucose, respectively. The same protein segment can be modified with a variety of glycans generating a wide structural diversity of Srr1. Electron transfer dissociation was used to assign glycosylation sites leading to the unambiguous identification of six serines and one threonine residues. Analysis of purified Srr1 produced in mutant strains lacking accessory glycosyltransferase encoding genes demonstrates that O-GlcNAcylation is an initial step in Srr1 glycosylation that is likely required for subsequent decoration with Hex. In summary, our data obtained by a combination of fragmentation mass spectrometry techniques associated to a new software tool, demonstrate glycosylation heterogeneity of Srr1, characterize a new protein modification, and identify six glycosylation sites located in the N-terminal region of the protein.
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Affiliation(s)
- Thibault Chaze
- From the ‡INRA, MICALIS UMR-1319, 78352 Jouy-en-Josas cedex, France; §AgroParisTech, MICALIS UMR-1319, 78352 Jouy-en-Josas cedex, France; ¶¶Institut Pasteur, Unité de Spectrométrie de Masse Structurale et Protéomique, 28 rue du Dr Roux, 75015 Paris, France
| | - Alain Guillot
- ¶INRA, PAPPSO, MICALIS UMR-1319, 78352 Jouy en Josas cedex, France
| | - Benoît Valot
- ‖INRA, PAPPSO, Génétique végétale UMR-320, Ferme du Moulon, 91190 Gif sur Yvette, France
| | - Olivier Langella
- ‖INRA, PAPPSO, Génétique végétale UMR-320, Ferme du Moulon, 91190 Gif sur Yvette, France
| | - Julia Chamot-Rooke
- ¶¶Institut Pasteur, Unité de Spectrométrie de Masse Structurale et Protéomique, 28 rue du Dr Roux, 75015 Paris, France; ‖‖CNRS UMR 3528, Institut Pasteur, 28 rue du Dr Roux, 75015 Paris, France
| | - Anne-Marie Di Guilmi
- **CEA, Institut de Biologie Structurale Jean-Pierre Ebel, F-38027 Grenoble, France
| | - Patrick Trieu-Cuot
- ‡‡Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram+, 28, rue du Dr Roux, 75015 Paris, France; §§Centre National de la Recherche Scientifique, CNRS ERL3526, Paris, France
| | - Shaynoor Dramsi
- ‡‡Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram+, 28, rue du Dr Roux, 75015 Paris, France; §§Centre National de la Recherche Scientifique, CNRS ERL3526, Paris, France
| | - Michel-Yves Mistou
- From the ‡INRA, MICALIS UMR-1319, 78352 Jouy-en-Josas cedex, France; §AgroParisTech, MICALIS UMR-1319, 78352 Jouy-en-Josas cedex, France;
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