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Wen YH, Chen DP. Human platelet antigens in disease. Clin Chim Acta 2018; 484:87-90. [PMID: 29802830 DOI: 10.1016/j.cca.2018.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 05/05/2018] [Accepted: 05/07/2018] [Indexed: 12/16/2022]
Abstract
Platelets have various functions and participate in primary hemostasis, inflammation, and immune responses. Human platelet antigens (HPAs) are alloantigens expressed on the platelet membrane. Each HPA represent one of six platelet glycoproteins GPIIb, GPIIIa, GPIa, GPIbα, GPIbβ, and CD109, and six biallelic systems are grouped. A single nucleotide polymorphism (SNP) in the gene sequence causes a single amino acid substitution of relevant platelet glycoprotein with the exception of HPA-14bw. High-throughput next-generation sequencing-based method has been developed, which enable accurately identification of HPA polymorphisms. The roles of HPA in disease were reviewed. HPAs mediate platelet-microorganism and platelet-malignant cell interactions, and they also participate in pathogenesis of hemorrhagic fever with renal syndrome and infective endocarditis. The exploration of HPA polymorphisms in association with disease susceptibility of individuals will benefit prevention or management of disease.
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Affiliation(s)
- Ying-Hao Wen
- Department of Laboratory Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ding-Ping Chen
- Department of Laboratory Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taiwan; Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
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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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Structural basis for the role of serine-rich repeat proteins from Lactobacillus reuteri in gut microbe-host interactions. Proc Natl Acad Sci U S A 2018; 115:E2706-E2715. [PMID: 29507249 PMCID: PMC5866549 DOI: 10.1073/pnas.1715016115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Gut bacteria play a key role in health and disease, but the molecular mechanisms underpinning their interaction with the host remain elusive. The serine-rich repeat proteins (SRRPs) are a family of adhesins identified in many Gram-positive pathogenic bacteria. We previously showed that beneficial bacterial species found in the gut also express SRRPs and that SRRP was required for the ability of Lactobacillus reuteri strain to colonize mice. Here, our structural and biochemical data reveal that L. reuteri SRRP adopts a β-solenoid fold not observed in other structurally characterized SRRPs and functions as an adhesin via a pH-dependent mechanism, providing structural insights into the role of these adhesins in biofilm formation of gut symbionts. Lactobacillus reuteri, a Gram-positive bacterial species inhabiting the gastrointestinal tract of vertebrates, displays remarkable host adaptation. Previous mutational analyses of rodent strain L. reuteri 100-23C identified a gene encoding a predicted surface-exposed serine-rich repeat protein (SRRP100-23) that was vital for L. reuteri biofilm formation in mice. SRRPs have emerged as an important group of surface proteins on many pathogens, but no structural information is available in commensal bacteria. Here we report the 2.00-Å and 1.92-Å crystal structures of the binding regions (BRs) of SRRP100-23 and SRRP53608 from L. reuteri ATCC 53608, revealing a unique β-solenoid fold in this important adhesin family. SRRP53608-BR bound to host epithelial cells and DNA at neutral pH and recognized polygalacturonic acid (PGA), rhamnogalacturonan I, or chondroitin sulfate A at acidic pH. Mutagenesis confirmed the role of the BR putative binding site in the interaction of SRRP53608-BR with PGA. Long molecular dynamics simulations showed that SRRP53608-BR undergoes a pH-dependent conformational change. Together, these findings provide mechanistic insights into the role of SRRPs in host–microbe interactions and open avenues of research into the use of biofilm-forming probiotics against clinically important pathogens.
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54
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Li J, Angsantikul P, Liu W, Esteban-Fernández de Ávila B, Chang X, Sandraz E, Liang Y, Zhu S, Zhang Y, Chen C, Gao W, Zhang L, Wang J. Biomimetic Platelet-Camouflaged Nanorobots for Binding and Isolation of Biological Threats. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1704800. [PMID: 29193346 DOI: 10.1002/adma.201704800] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/29/2017] [Indexed: 05/18/2023]
Abstract
One emerging and exciting topic in robotics research is the design of micro-/nanoscale robots for biomedical operations. Unlike industrial robots that are developed primarily to automate routine and dangerous tasks, biomedical nanorobots are designed for complex, physiologically relevant environments, and tasks that involve unanticipated biological events. Here, a biologically interfaced nanorobot is reported, made of magnetic helical nanomotors cloaked with the plasma membrane of human platelets. The resulting biomimetic nanorobots possess a biological membrane coating consisting of diverse functional proteins associated with human platelets. Compared to uncoated nanomotors which experience severe biofouling effects and hence hindered propulsion in whole blood, the platelet-membrane-cloaked nanomotors disguise as human platelets and display efficient propulsion in blood over long time periods. The biointerfaced nanorobots display platelet-mimicking properties, including adhesion and binding to toxins and platelet-adhering pathogens, such as Shiga toxin and Staphylococcus aureus bacteria. The locomotion capacity and platelet-mimicking biological function of the biomimetic nanomotors offer efficient binding and isolation of these biological threats. The dynamic biointerfacing platform enabled by platelet-membrane cloaked nanorobots thus holds considerable promise for diverse biomedical and biodefense applications.
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Affiliation(s)
- Jinxing Li
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Pavimol Angsantikul
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Wenjuan Liu
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | | | - Xiaocong Chang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Elodie Sandraz
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Yuyan Liang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Siyu Zhu
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Yue Zhang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Chuanrui Chen
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Weiwei Gao
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Liangfang Zhang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
| | - Joseph Wang
- Department of NanoEngineering, University of California San Diego, La Jolla, CA, 92093, USA
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55
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Lee JY, Han GG, Kim EB, Choi YJ. Comparative genomics of Lactobacillus salivarius strains focusing on their host adaptation. Microbiol Res 2017; 205:48-58. [DOI: 10.1016/j.micres.2017.08.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 07/25/2017] [Accepted: 08/12/2017] [Indexed: 01/15/2023]
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Liu X, Liu H, Luo X, Zhang P, Gao Y, Xie S, Xu K, Chang J, Ma L. Strains of Group B streptococci from septic patients induce platelet activation via Toll-like Receptor 2. Clin Exp Pharmacol Physiol 2017; 44:335-343. [PMID: 27885699 DOI: 10.1111/1440-1681.12707] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 11/16/2016] [Accepted: 11/19/2016] [Indexed: 11/28/2022]
Abstract
Group B Streptococcus (GBS) causes life-threatening bacterial sepsis, especially in newborns and pregnant women. Patients suffering from sepsis often display low platelet counts, characterized by thrombocytopenia, because of platelet activation. In the present study, the roles of six GBS strains from septic patients in platelet aggregation, as well as the underlying mechanisms, were investigated. Incubation of platelets with three of the strains induced platelet aggregation, increased the secretion of cellular adhesin molecule CD62P and activation of GPIIb/IIIa. Furthermore, the GBS strains that induced platelet activation also caused an increase in the expression of Toll-like receptor (TLR) 2 in platelets. Pre-incubation of platelets with anti-TLR2 monoclonal antibody, but not anti-TLR4 monoclonal antibody, inhibited these functional responses induced by GBS. TLR2 stimulation also activated the phosphoinositide 3-kinase (PI3-K)/Akt signalling pathway in platelets, and inhibition of PI3-K significantly reduced GBS-induced platelet responses. Our results indicate that three of the GBS strains from the septic patients can trigger platelet activation by interacting with platelets, which involves the elevation of platelet TLR2 expression.
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Affiliation(s)
- Xiaoyan Liu
- Department of Hematology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Hongyun Liu
- Department of Hematology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xianming Luo
- Department of Hematology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Ping Zhang
- Department of Hematology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yanmin Gao
- Department of Hematology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Shuangfeng Xie
- Department of Hematology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Kang Xu
- Department of General surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jianxing Chang
- Department of General surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Liping Ma
- Department of Hematology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
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57
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van der Mee-Marquet N, Diene SM, Barbera L, Courtier-Martinez L, Lafont L, Ouachée A, Valentin AS, Santos SD, Quentin R, François P. Analysis of the prophages carried by human infecting isolates provides new insight into the evolution of Group B Streptococcus species. Clin Microbiol Infect 2017; 24:514-521. [PMID: 28870726 DOI: 10.1016/j.cmi.2017.08.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 07/25/2017] [Accepted: 08/24/2017] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Group B Streptococcus (GBS) emerged in the 1970s as a major cause of neonatal infections, and has been increasingly associated with infections in adults since the 1990s. Prophages have been suspected to have driven these epidemiological trends. We have characterized the prophages harboured by 275 human GBS isolates belonging to the major lineages. METHODS We applied whole genome sequencing (WGS) to 14 isolates representative of the diversity within GBS species, located and identified their prophages. Using prediction tools, we searched for prophage elements potentially involved with the ability of GBS to infect humans. Using the data obtained by WGS, we designed a PCR-based tool and studied the prophage content of 275 isolates. RESULTS WGS of the 14 isolates revealed 22 prophages (i) distributed into six groups (A-F), (ii) similar to phages and prophages from GBS and non-GBS streptococci recovered from livestock, and (iii) carrying genes encoding factors previously associated with host adaptation and virulence. PCR-based detection of prophages revealed the presence of at least one prophage in 72.4% of the 275 isolates and a significant association between neonatal infecting isolates and prophages C, and between adult infecting isolates and prophages A. CONCLUSIONS Our results suggest that prophages (possibly animal-associated) have conditioned bacterial adaptation and ability to cause infections in neonates and adults, and support a role of lysogeny with the emergence of GBS as a pathogen in human.
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Affiliation(s)
- N van der Mee-Marquet
- UMR 1282, Infectiologie Santé Publique, Université François Rabelais, France; Service de Bactériologie, Virologie et Hygiène, France; Réseau des Hygiénistes du Centre, CPIAS Centre Val de Loire, Centre Hospitalier Régional Universitaire, Tours, France.
| | - S M Diene
- Faculté de Médecine et de Pharmacie, URMITE, Aix-Marseille université, UMR 63, CNRS 7278, IRD 198, INSERM 1095, IHU-Méditerranée Infection, Marseille, France
| | - L Barbera
- UMR 1282, Infectiologie Santé Publique, Université François Rabelais, France
| | - L Courtier-Martinez
- UMR 1282, Infectiologie Santé Publique, Université François Rabelais, France
| | - L Lafont
- UMR 1282, Infectiologie Santé Publique, Université François Rabelais, France
| | - A Ouachée
- UMR 1282, Infectiologie Santé Publique, Université François Rabelais, France
| | - A-S Valentin
- UMR 1282, Infectiologie Santé Publique, Université François Rabelais, France; Service de Bactériologie, Virologie et Hygiène, France
| | - S Dos Santos
- Service de Bactériologie, Virologie et Hygiène, France
| | - R Quentin
- UMR 1282, Infectiologie Santé Publique, Université François Rabelais, France; Service de Bactériologie, Virologie et Hygiène, France
| | - P François
- Genomic Research Laboratory, Service of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland(†)
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58
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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: 17] [Impact Index Per Article: 2.4] [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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Quantitative Expression Analysis of SpA, FnbA and Rsp Genes in Staphylococcus aureus: Actively Associated in the Formation of Biofilms. Curr Microbiol 2017; 74:1394-1403. [DOI: 10.1007/s00284-017-1331-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 08/07/2017] [Indexed: 10/19/2022]
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60
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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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61
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Zhu F, Zhang H, Yang T, Haslam SM, Dell A, Wu H. Engineering and Dissecting the Glycosylation Pathway of a Streptococcal Serine-rich Repeat Adhesin. J Biol Chem 2017; 291:27354-27363. [PMID: 28039332 PMCID: PMC5207161 DOI: 10.1074/jbc.m116.752998] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/11/2016] [Indexed: 11/24/2022] Open
Abstract
Serine-rich repeat glycoproteins (SRRPs) are conserved in Gram-positive bacteria. They are crucial for modulating biofilm formation and bacterial-host interactions. Glycosylation of SRRPs plays a pivotal role in the process; thus understanding the glycosyltransferases involved is key to identifying new therapeutic drug targets. The glycosylation of Fap1, an SRRP of Streptococcus parasanguinis, is mediated by a gene cluster consisting of six genes: gtf1, gtf2, gly, gtf3, dGT1, and galT2. Mature Fap1 glycan possesses the sequence of Rha1–3Glc1-(Glc1–3GlcNAc1)-2,6-Glc1–6GlcNAc. Gtf12, Gtf3, and dGT1 are responsible for the first four steps of the Fap1 glycosylation, catalyzing the transfer of GlcNAc, Glc, Glc, and GlcNAc residues to the protein backbone sequentially. The role of GalT2 and Gly in the Fap1 glycosylation is unknown. In the present study, we synthesized the fully modified Fap1 glycan in Escherichia coli by incorporating all six genes from the cluster. This study represents the first reconstitution of an exogenous stepwise O-glycosylation synthetic pathway in E. coli. In addition, we have determined that GalT2 mediates the fifth step of the Fap1 glycosylation by adding a rhamnose residue, and Gly mediates the final glycosylation step by transferring glucosyl residues. Furthermore, inactivation of each glycosyltransferase gene resulted in differentially impaired biofilms of S. parasanguinis, demonstrating the importance of Fap1 glycosylation in the biofilm formation. The Fap1 glycosylation system offers an excellent model to engineer glycans using different permutations of glycosyltransferases and to investigate biosynthetic pathways of SRRPs because SRRP genetic loci are highly conserved.
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Affiliation(s)
- Fan Zhu
- From the Departments of Pediatric Dentistry and.,Microbiology, University of Alabama at Birmingham, Schools of Dentistry and Medicine, Birmingham, Alabama 35244 and
| | - Hua Zhang
- From the Departments of Pediatric Dentistry and
| | - Tiandi Yang
- the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Stuart M Haslam
- the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Anne Dell
- the Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Hui Wu
- From the Departments of Pediatric Dentistry and .,Microbiology, University of Alabama at Birmingham, Schools of Dentistry and Medicine, Birmingham, Alabama 35244 and
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Gram-Positive Uropathogens, Polymicrobial Urinary Tract Infection, and the Emerging Microbiota of the Urinary Tract. Microbiol Spectr 2017; 4. [PMID: 27227294 DOI: 10.1128/microbiolspec.uti-0012-2012] [Citation(s) in RCA: 195] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Gram-positive bacteria are a common cause of urinary-tract infection (UTI), particularly among individuals who are elderly, pregnant, or who have other risk factors for UTI. Here we review the epidemiology, virulence mechanisms, and host response to the most frequently isolated Gram-positive uropathogens: Staphylococcus saprophyticus, Enterococcus faecalis, and Streptococcus agalactiae. We also review several emerging, rare, misclassified, and otherwise underreported Gram-positive pathogens of the urinary tract including Aerococcus, Corynebacterium, Actinobaculum, and Gardnerella. The literature strongly suggests that urologic diseases involving Gram-positive bacteria may be easily overlooked due to limited culture-based assays typically utilized for urine in hospital microbiology laboratories. Some UTIs are polymicrobial in nature, often involving one or more Gram-positive bacteria. We herein review the risk factors and recent evidence for mechanisms of bacterial synergy in experimental models of polymicrobial UTI. Recent experimental data has demonstrated that, despite being cleared quickly from the bladder, some Gram-positive bacteria can impact pathogenic outcomes of co-infecting organisms. When taken together, the available evidence argues that Gram-positive bacteria are important uropathogens in their own right, but that some can be easily overlooked because they are missed by routine diagnostic methods. Finally, a growing body of evidence demonstrates that a surprising variety of fastidious Gram-positive bacteria may either reside in or be regularly exposed to the urinary tract and further suggests that their presence is widespread among women, as well as men. Experimental studies in this area are needed; however, there is a growing appreciation that the composition of bacteria found in the bladder could be a potentially important determinant in urologic disease, including susceptibility to UTI.
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63
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Abstract
All bacteria utilize pathways to export proteins from the cytoplasm to the bacterial cell envelope or extracellular space. Many exported proteins function in essential physiological processes or in virulence. Consequently, the responsible protein export pathways are commonly essential and/or are important for pathogenesis. The general Sec protein export pathway is conserved and essential in all bacteria, and it is responsible for most protein export. The energy for Sec export is provided by the SecA ATPase. Mycobacteria and some Gram-positive bacteria have two SecA paralogs: SecA1 and SecA2. SecA1 is essential and works with the canonical Sec pathway to perform the bulk of protein export. The nonessential SecA2 exports a smaller subset of proteins and is required for the virulence of pathogens such as Mycobacterium tuberculosis. In this article, we review our current understanding of the mechanism of the SecA1 and SecA2 export pathways and discuss some of their better-studied exported substrates. We focus on proteins with established functions in M. tuberculosis pathogenesis and proteins that suggest potential roles for SecA1 and SecA2 in M. tuberculosis dormancy.
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64
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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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Yang Y, Yu R, Yang X, Liu S, Fang T, Song X, Hou L, Yu C, Xu J, Fu L, Yi S, Chen W. Protection against Staphylococcus aureus and tetanus infections by a combined vaccine containing SasA and TeNT‑Hc in mice. Mol Med Rep 2017; 15:2369-2373. [PMID: 28259925 DOI: 10.3892/mmr.2017.6227] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 12/19/2016] [Indexed: 11/06/2022] Open
Abstract
In developing countries, trauma patients and neonates are vulnerable to Staphylococcus aureus (S. aureus) and Clostridium tetani infections. It has been suggested that a combined vaccine against the two infections may be a reliable and cost‑effective strategy. Previous studies have indicated that the S. aureus surface protein A (SasA) and the C fragment of tetanus neurotoxin (TeNT‑Hc) may be suitable candidates for a vaccine against S. aureus and tetanus infections, respectively. In the present study, mice were immunized with a combined vaccine containing SasA and TeNT‑Hc, which induced a robust immune response to both antigens, and mutual interference between SasA and TeNT‑Hc was not observed. In the S.aureus challenge model, the combined vaccine fully protected BALB/c mice against lethal intraperitoneal challenges with 3x109 colony‑forming units of a methicillin‑resistant S. aureus USA300 strain. In the TeNT challenge model, the combined vaccine conferred complete protection against a lethal dose of (2x103) xLD50 tetanus toxin. These results implied that SasA and TeNT‑Hc promising components for a combined vaccine against S. aureus and tetanus infections.
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Affiliation(s)
- Yilong Yang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Rui Yu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Xiuxu Yang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Shuling Liu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Ting Fang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Xiaohong Song
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Lihua Hou
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Changming Yu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Junjie Xu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Ling Fu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Shaoqiong Yi
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
| | - Wei Chen
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Fengtai, Beijing 100071, P.R. China
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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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Banskota S, Yousefpour P, Chilkoti A. Cell-Based Biohybrid Drug Delivery Systems: The Best of the Synthetic and Natural Worlds. Macromol Biosci 2016; 17. [DOI: 10.1002/mabi.201600361] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/18/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Samagya Banskota
- Department of Biomedical Engineering; Duke University; Durham NC 27708 USA
| | - Parisa Yousefpour
- Department of Biomedical Engineering; Duke University; Durham NC 27708 USA
| | - Ashutosh Chilkoti
- Department of Biomedical Engineering; Duke University; Durham NC 27708 USA
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Computational Discovery of Putative Leads for Drug Repositioning through Drug-Target Interaction Prediction. PLoS Comput Biol 2016; 12:e1005219. [PMID: 27893735 PMCID: PMC5125559 DOI: 10.1371/journal.pcbi.1005219] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 10/21/2016] [Indexed: 12/23/2022] Open
Abstract
De novo experimental drug discovery is an expensive and time-consuming task. It requires the identification of drug-target interactions (DTIs) towards targets of biological interest, either to inhibit or enhance a specific molecular function. Dedicated computational models for protein simulation and DTI prediction are crucial for speed and to reduce the costs associated with DTI identification. In this paper we present a computational pipeline that enables the discovery of putative leads for drug repositioning that can be applied to any microbial proteome, as long as the interactome of interest is at least partially known. Network metrics calculated for the interactome of the bacterial organism of interest were used to identify putative drug-targets. Then, a random forest classification model for DTI prediction was constructed using known DTI data from publicly available databases, resulting in an area under the ROC curve of 0.91 for classification of out-of-sampling data. A drug-target network was created by combining 3,081 unique ligands and the expected ten best drug targets. This network was used to predict new DTIs and to calculate the probability of the positive class, allowing the scoring of the predicted instances. Molecular docking experiments were performed on the best scoring DTI pairs and the results were compared with those of the same ligands with their original targets. The results obtained suggest that the proposed pipeline can be used in the identification of new leads for drug repositioning. The proposed classification model is available at http://bioinformatics.ua.pt/software/dtipred/. The emergence of multi-resistant bacterial strains and the existing void in the discovery and development of new classes of antibiotics is a growing concern. Indeed, some bacterial strains are now resistant to last-line antibiotics and considered untreatable. Drug repositioning has been suggested as a strategy to minimize time and cost expenses until the drug reaches the market, compared to traditional drug design. Drug-target interactions (DTIs) are the basis of rational drug design and thus, we proposed a computational approach to predict DTIs solely based on the primary sequence of the protein and the simplified molecular-input line-entry system of the ligand. In addition, network metrics are used to identify vital putative drug-targets in bacteria. Molecular docking experiments were performed to compare the binding affinities between a given ligand and a putative drug-target, as well as with their original targets. According to the docking results, the predicted DTIs have better or similar binding activities than the ligand and their real target, indicating the validity of the proposed model.
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Loukachevitch LV, Bensing BA, Yu H, Zeng J, Chen X, Sullam PM, Iverson TM. Structures of the Streptococcus sanguinis SrpA Binding Region with Human Sialoglycans Suggest Features of the Physiological Ligand. Biochemistry 2016; 55:5927-5937. [PMID: 27685666 PMCID: PMC5388602 DOI: 10.1021/acs.biochem.6b00704] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Streptococcus sanguinis is a leading cause of bacterial infective endocarditis, a life-threatening infection of heart valves. S. sanguinis binds to human platelets with high avidity, and this adherence is likely to enhance virulence. Previous studies suggest that a serine-rich repeat adhesin termed SrpA mediates the binding of S. sanguinis to human platelets via its interaction with sialoglycans on the receptor GPIbα. However, in vitro binding assays with SrpA and defined sialoglycans failed to identify specific high-affinity ligands. To improve our understanding of the interaction between SrpA and human platelets, we determined cocrystal structures of the SrpA sialoglycan binding region (SrpABR) with five low-affinity ligands: three sialylated trisaccharides (sialyl-T antigen, 3'-sialyllactose, and 3'-sialyl-N-acetyllactosamine), a sialylated tetrasaccharide (sialyl-LewisX), and a sialyl galactose disaccharide component common to these sialoglyans. We then combined structural analysis with mutagenesis to further determine whether our observed interactions between SrpABR and glycans are important for binding to platelets and to better map the binding site for the physiological receptor. We found that the sialoglycan binding site of SrpABR is significantly larger than the sialoglycans cocrystallized in this study, which suggests that binding of SrpA to platelets either is multivalent or occurs via a larger, disialylated glycan.
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Affiliation(s)
| | - Barbara A. Bensing
- Division of Infectious Diseases, Veterans Affairs Medical Center, University of California at San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121, USA
| | - Hai Yu
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Jie Zeng
- Department of Chemistry, University of California, Davis, CA 95616, USA,School of Food Science, Henan Institute of Science and Technology, Xinxiang, 453003, China
| | - Xi Chen
- Department of Chemistry, University of California, Davis, CA 95616, USA
| | - Paul M. Sullam
- Division of Infectious Diseases, Veterans Affairs Medical Center, University of California at San Francisco and the Northern California Institute for Research and Education, San Francisco, California 94121, USA
| | - T M Iverson
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, USA,Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232, USA,Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, USA,Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37232, USA,Corresponding Author To whom correspondence should be addressed:
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Abstract
The primary function of platelets is to patrol the vasculature and seal vessel breaches to limit blood loss. However, it is becoming increasingly clear that they also contribute to pathophysiological conditions like thrombosis, atherosclerosis, stroke and infection. Severe sepsis is a devastating disease that claims hundreds of thousands of lives every year in North America and is a major burden to the public health system. Platelet surface receptors like GPIb, αIIbβ3, TLR2 and TLR4 are involved in direct platelet-bacteria interactions. Plasma proteins like fibrinogen and vWF enable indirect interactions. Furthermore, platelet granules contain a plethora of proteins that modulate the immune response as well as microbicidal agents which can directly lyse bacteria. Bacterial toxins are potent platelet activators and can cause intravascular platelet aggregation. Platelets contribute to the antibacterial response of the host involving Kupffer cells, neutrophils and the complement system. In this review we summarize the current knowledge about platelet-bacteria interactions and highlight recent advances in the field.
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Affiliation(s)
- Carsten Deppermann
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada
| | - Paul Kubes
- Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, University of Calgary, Calgary, AB, Canada.
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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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Zhang H, Zhou M, Yang T, Haslam SM, Dell A, Wu H. New Helical Binding Domain Mediates a Glycosyltransferase Activity of a Bifunctional Protein. J Biol Chem 2016; 291:22106-22117. [PMID: 27539847 PMCID: PMC5063993 DOI: 10.1074/jbc.m116.731695] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Indexed: 11/08/2022] Open
Abstract
Serine-rich repeat glycoproteins (SRRPs) conserved in streptococci and staphylococci are important for bacterial colonization and pathogenesis. Fap1, a well studied SRRP is a major surface constituent of Streptococcus parasanguinis and is required for bacterial adhesion and biofilm formation. Biogenesis of Fap1 is a multistep process that involves both glycosylation and secretion. A series of glycosyltransferases catalyze sequential glycosylation of Fap1. We have identified a unique hybrid protein dGT1 (dual glycosyltransferase 1) that contains two distinct domains. N-terminal DUF1792 is a novel GT-D-type glycosyltransferase, transferring Glc residues to Glc-GlcNAc-modified Fap1. C-terminal dGT1 (CgT) is predicted to possess a typical GT-A-type glycosyltransferase, however, the activity remains unknown. In this study, we determine that CgT is a distinct glycosyltransferase, transferring GlcNAc residues to Glc-Glc-GlcNAc-modified Fap1. A 2.4-Å x-ray crystal structure reveals that CgT has a unique binding domain consisting of three α helices in addition to a typical GT-A-type glycosyltransferase domain. The helical domain is crucial for the oligomerization of CgT. Structural and biochemical studies revealed that the helix domain is required for the protein-protein interaction and crucial for the glycosyltransferase activity of CgT in vitro and in vivo. As the helix domain presents a novel structural fold, we conclude that CgT represents a new member of GT-A-type glycosyltransferases.
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Affiliation(s)
- Hua Zhang
- From the Departments of Pediatric Dentistry and Microbiology, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294 and
| | - Meixian Zhou
- From the Departments of Pediatric Dentistry and Microbiology, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294 and
| | - Tiandi Yang
- the Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Stuart M Haslam
- the Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Anne Dell
- the Department of Life Sciences, Imperial College London, London, SW7 2AZ, United Kingdom
| | - Hui Wu
- From the Departments of Pediatric Dentistry and Microbiology, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294 and
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Dehaini D, Fang RH, Zhang L. Biomimetic strategies for targeted nanoparticle delivery. Bioeng Transl Med 2016; 1:30-46. [PMID: 29313005 PMCID: PMC5689512 DOI: 10.1002/btm2.10004] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Revised: 04/07/2016] [Accepted: 04/08/2016] [Indexed: 01/02/2023] Open
Abstract
Nanoparticle‐based drug delivery and imaging platforms have become increasingly popular over the past several decades. Among different design parameters that can affect their performance, the incorporation of targeting functionality onto nanoparticle surfaces has been a widely studied subject. Targeted formulations have the ability to improve efficacy and function by positively modulating tissue localization. Many methods exist for creating targeted nanoformulations, including the use of custom biomolecules such as antibodies or aptamers. More recently, a great amount of focus has been placed on biomimetic targeting strategies that leverage targeting interactions found directly in nature. Such strategies, which have been painstakingly selected over time by the process of evolution to maximize functionality, oftentimes enable scientists to forgo the specialized discovery processes associated with many traditional ligands and help to accelerate development of novel nanoparticle formulations. In this review, we categorize and discuss in‐depth recent works in this growing field of bioinspired research.
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Affiliation(s)
- Diana Dehaini
- Dept. of NanoEngineering and Moores Cancer Center University of California San Diego, La Jolla CA 92093
| | - Ronnie H Fang
- Dept. of NanoEngineering and Moores Cancer Center University of California San Diego, La Jolla CA 92093
| | - Liangfang Zhang
- Dept. of NanoEngineering and Moores Cancer Center University of California San Diego, La Jolla CA 92093
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The Staphylococcus aureus Global Regulator MgrA Modulates Clumping and Virulence by Controlling Surface Protein Expression. PLoS Pathog 2016; 12:e1005604. [PMID: 27144398 PMCID: PMC4856396 DOI: 10.1371/journal.ppat.1005604] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 04/07/2016] [Indexed: 02/07/2023] Open
Abstract
Staphylococcus aureus is a human commensal and opportunistic pathogen that causes devastating infections in a wide range of locations within the body. One of the defining characteristics of S. aureus is its ability to form clumps in the presence of soluble fibrinogen, which likely has a protective benefit and facilitates adhesion to host tissue. We have previously shown that the ArlRS two-component regulatory system controls clumping, in part by repressing production of the large surface protein Ebh. In this work we show that ArlRS does not directly regulate Ebh, but instead ArlRS activates expression of the global regulator MgrA. Strains lacking mgrA fail to clump in the presence of fibrinogen, and clumping can be restored to an arlRS mutant by overexpressing either arlRS or mgrA, indicating that ArlRS and MgrA constitute a regulatory pathway. We used RNA-seq to show that MgrA represses ebh, as well as seven cell wall-associated proteins (SraP, Spa, FnbB, SasG, SasC, FmtB, and SdrD). EMSA analysis showed that MgrA directly represses expression of ebh and sraP. Clumping can be restored to an mgrA mutant by deleting the genes for Ebh, SraP and SasG, suggesting that increased expression of these proteins blocks clumping by steric hindrance. We show that mgrA mutants are less virulent in a rabbit model of endocarditis, and virulence can be partially restored by deleting the genes for the surface proteins ebh, sraP, and sasG. While mgrA mutants are unable to clump, they are known to have enhanced biofilm capacity. We demonstrate that this increase in biofilm formation is partially due to up-regulation of SasG, a surface protein known to promote intercellular interactions. These results confirm that ArlRS and MgrA constitute a regulatory cascade, and that they control expression of a number of genes important for virulence, including those for eight large surface proteins. Staphylococcus causes a wide range of diseases, ranging from skin infections to deadly invasive condition like endocarditis, septicemia, osteomyelitis, and pneumonia. In this work we examine the ArlRS two-component regulatory system, which controls interactions with the host plasma protein fibrinogen. S. aureus normally forms large aggregates called clumps in the presence of fibrinogen, but the arlRS mutant is unable to clump. We demonstrate that ArlRS activates expression of the DNA-binding protein MgrA, and that mgrA is also required for clumping. Transcriptional analysis of an mgrA mutant shows that MgrA regulates expression of eight surface proteins. Expression of these surface proteins affects clumping, possibly by physically interfering with fibrinogen binding. Strains lacking mgrA are less virulent in an endocarditis model, and virulence can be partially restored by deleting genes for three of these surface proteins. An mgrA mutant is also known to have enhanced biofilm formation, and we show that this is partially due to increased production of one of these surface proteins. These results demonstrate that ArlRS and MgrA constitute a regulatory cascade in S. aureus that is crucial for pathogenesis and may be a good candidate to target for drug development.
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75
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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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76
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Moriarty RD, Cox A, McCall M, Smith SGJ, Cox D. Escherichia coli induces platelet aggregation in an FcγRIIa-dependent manner. J Thromb Haemost 2016; 14:797-806. [PMID: 26669970 DOI: 10.1111/jth.13226] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 11/30/2015] [Indexed: 12/20/2022]
Abstract
BACKGROUND The discovery of pathogen-recognition receptors such as Toll-like receptors on platelets has led to the emergence of the concept of platelets as important components of the host response to infection. Escherichia coli (E. coli)-mediated sepsis is a serious illness characterized by the occurrence of thrombocytopenia. Whereas there has been a wealth of research on platelet activation by Gram-positive bacteria, little is known about the mechanisms associated with Gram-negative bacteria-induced platelet activation with Gram-negative bacteria. OBJECTIVES To determine the mechanisms by which Gram-negative E. coli induces platelet aggregation. METHODS Induction of platelet aggregation with E. coli strain O157:H7 was tested in platelet-rich plasma (PRP), washed platelets, and serum depleted of complement factors. Platelet inhibitors (against αII b β3 , glycoprotein Ibα and FcγRIIa) were used. Platelet thromboxane synthesis was analyzed after E. coli stimulation. Cell binding assays were used to assess the ability of E. coli to support platelet adhesion. Trypsinization was used to determine the role of E. coli surface proteins. RESULTS AND CONCLUSION E. coli-induced aggregation in PRP was donor-dependent. E. coli O157:H7 induced aggregation with a lag time of 6.9 ± 1.3 min in an αII b β3 -dependent and FcγRIIa-dependent manner. Furthermore, this interaction was enhanced by the presence of complement, and was dependent on thromboxane synthesis. These results show E. coli to be a potent inducer of platelet aggregation.
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Affiliation(s)
- R D Moriarty
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - A Cox
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - M McCall
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - S G J Smith
- Department of Clinical Microbiology, School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - D Cox
- Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
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77
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Yang Y, Qian M, Yi S, Liu S, Li B, Yu R, Guo Q, Zhang X, Yu C, Li J, Xu J, Chen W. Monoclonal Antibody Targeting Staphylococcus aureus Surface Protein A (SasA) Protect Against Staphylococcus aureus Sepsis and Peritonitis in Mice. PLoS One 2016; 11:e0149460. [PMID: 26926145 PMCID: PMC4771200 DOI: 10.1371/journal.pone.0149460] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 02/01/2016] [Indexed: 02/06/2023] Open
Abstract
Epidemic methicillin-resistant Staphylococcus aureus (MRSA) imposes an increasing impact on public health. Due to multi-antibiotics resistance in MRSA strains, there is an urgent need to develop novel therapeutics such as effective monoclonal antibodies (mAbs) against MRSA infections. Staphylococcus aureus surface protein A (SasA), a large surface-located protein (~240 kDa), is one of MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) and a potential target for immunotherapeutic approaches against S. aureus infections. In the present study, we analyzed the sequence of SasA with bioinformatics tools and generated a protective monoclonal antibody (2H7) targeting the conserved domain of SasA. 2H7 was shown to recognize wild-type S. aureus and promote opsonophagocytic killing of S. aureus. In both sepsis and peritoneal infection models, prophylactic administration of 2H7 improved the survival of BALB/c mice challenged by S. aureus strain USA300 and ST239 (prevalent MRSA clones in North America and Asian countries, respectively) and enhanced bacterial clearance in kidneys. Additionally, 2H7 prophylaxis prevented the formation of intraperitoneal abscess in a murine model of peritoneal infection and therapeutic administration of 2H7 showed protective efficacy in a murine sepsis model. Our results presented here provide supporting evidences that an anti-SasA mAb might be a potential component in an antibody-based immunotherapeutic treatment of MRSA infections.
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Affiliation(s)
- Yilong Yang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Mengying Qian
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Shaoqiong Yi
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Shuling Liu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Bing Li
- Department of Clinical Laboratory, 306 Hospital of People’s Liberation Army, Beijing, PR China
| | - Rui Yu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Qiang Guo
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Xiaopeng Zhang
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Changming Yu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Jianmin Li
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Junjie Xu
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
| | - Wei Chen
- Laboratory of Vaccine and Antibody Engineering, Beijing Institute of Biotechnology, Beijing, PR China
- * E-mail:
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78
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Mechanism of a cytosolic O-glycosyltransferase essential for the synthesis of a bacterial adhesion protein. Proc Natl Acad Sci U S A 2016; 113:E1190-9. [PMID: 26884191 DOI: 10.1073/pnas.1600494113] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
O-glycosylation of Ser and Thr residues is an important process in all organisms, which is only poorly understood. Such modification is required for the export and function of adhesin proteins that mediate the attachment of pathogenic Gram-positive bacteria to host cells. Here, we have analyzed the mechanism by which the cytosolic O-glycosyltransferase GtfA/B of Streptococcus gordonii modifies the Ser/Thr-rich repeats of adhesin. The enzyme is a tetramer containing two molecules each of GtfA and GtfB. The two subunits have the same fold, but only GtfA contains an active site, whereas GtfB provides the primary binding site for adhesin. During a first phase of glycosylation, the conformation of GtfB is restrained by GtfA to bind substrate with unmodified Ser/Thr residues. In a slow second phase, GtfB recognizes residues that are already modified with N-acetylglucosamine, likely by converting into a relaxed conformation in which one interface with GtfA is broken. These results explain how the glycosyltransferase modifies a progressively changing substrate molecule.
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79
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Arora S, Uhlemann AC, Lowy FD, Hook M. A Novel MSCRAMM Subfamily in Coagulase Negative Staphylococcal Species. Front Microbiol 2016; 7:540. [PMID: 27199900 PMCID: PMC4850167 DOI: 10.3389/fmicb.2016.00540] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/01/2016] [Indexed: 12/14/2022] Open
Abstract
Coagulase negative staphylococci (CoNS) are important opportunistic pathogens. Staphylococcus epidermidis, a coagulase negative staphylococcus, is the third leading cause of nosocomial infections in the US. Surface proteins like Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs) are major virulence factors of pathogenic gram positive bacteria. Here, we identified a new chimeric protein in S. epidermidis, that we call SesJ. SesJ represents a prototype of a new subfamily of MSCRAMMs. Structural predictions show that SesJ has structural features characteristic of a MSCRAMM along with a N-terminal repeat region and an aspartic acid containing C-terminal repeat region, features that have not been previously observed in staphylococcal MSCRAMMs but have been found in other surface proteins from gram positive bacteria. We identified and analyzed structural homologs of SesJ in three other CoNS. These homologs of SesJ have an identical structural organization but varying sequence identities within the domains. Using flow cytometry, we also show that SesJ is expressed constitutively on the surface of a representative S. epidermidis strain, from early exponential to stationary growth phase. Thus, SesJ is positioned to interact with protein targets in the environment and plays a role in S. epidermidis virulence.
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Affiliation(s)
- Srishtee Arora
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, HoustonTX, USA
| | - Anne-Catrin Uhlemann
- Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University in the City of New York, New YorkNY, USA
| | - Franklin D. Lowy
- Division of Infectious Diseases, Department of Medicine, College of Physicians and Surgeons, Columbia University in the City of New York, New YorkNY, USA
| | - Magnus Hook
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M University Health Science Center, HoustonTX, USA
- *Correspondence: Magnus Hook,
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80
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Zhu F, Wu H. Insights into bacterial protein glycosylation in human microbiota. SCIENCE CHINA. LIFE SCIENCES 2016; 59:11-8. [PMID: 26712033 PMCID: PMC5298937 DOI: 10.1007/s11427-015-4980-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 11/05/2015] [Indexed: 01/14/2023]
Abstract
The study of human microbiota is an emerging research topic. The past efforts have mainly centered on studying the composition and genomic landscape of bacterial species within the targeted communities. The interaction between bacteria and hosts is the pivotal event in the initiation and progression of infectious diseases. There is a great need to identify and characterize the molecules that mediate the bacteria-host interaction. Bacterial surface exposed proteins play an important role in the bacteria- host interaction. Numerous surface proteins are glycosylated, and the glycosylation is crucial for their function in mediating the bacterial interaction with hosts. Here we present an overview of surface glycoproteins from bacteria that inhabit three major mucosal environments across human body: oral, gut and skin. We describe the important enzymes involved in the process of protein glycosylation, and discuss how the process impacts the bacteria-host interaction. Emerging molecular details underlying glycosylation of bacterial surface proteins may lead to new opportunities for designing anti-infective small molecules, and developing novel vaccines in order to treat or prevent bacterial infection.
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Affiliation(s)
- Fan Zhu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Hui Wu
- Departments of Microbiology and Pediatric Dentistry, Schools of Dentistry and Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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81
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Prabudiansyah I, Driessen AJM. The Canonical and Accessory Sec System of Gram-positive Bacteria. Curr Top Microbiol Immunol 2016; 404:45-67. [DOI: 10.1007/82_2016_9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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82
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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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83
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Garciarena CD, McHale TM, Watkin RL, Kerrigan SW. Coordinated Molecular Cross-Talk between Staphylococcus aureus, Endothelial Cells and Platelets in Bloodstream Infection. Pathogens 2015; 4:869-82. [PMID: 26690226 PMCID: PMC4693168 DOI: 10.3390/pathogens4040869] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Accepted: 12/02/2015] [Indexed: 01/06/2023] Open
Abstract
Staphylococcus aureus is an opportunistic pathogen often carried asymptomatically on the human body. Upon entry to the otherwise sterile environment of the cardiovascular system, S. aureus can lead to serious complications resulting in organ failure and death. The success of S. aureus as a pathogen in the bloodstream is due to its ability to express a wide array of cell wall proteins on its surface that recognise host receptors, extracellular matrix proteins and plasma proteins. Endothelial cells and platelets are important cells in the cardiovascular system and are a major target of bloodstream infection. Endothelial cells form the inner lining of a blood vessel and provide an antithrombotic barrier between the vessel wall and blood. Platelets on the other hand travel throughout the cardiovascular system and respond by aggregating around the site of injury and initiating clot formation. Activation of either of these cells leads to functional dysregulation in the cardiovascular system. In this review, we will illustrate how S. aureus establish intimate interactions with both endothelial cells and platelets leading to cardiovascular dysregulation.
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Affiliation(s)
- Carolina D Garciarena
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
| | - Tony M McHale
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
| | - Rebecca L Watkin
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
| | - Steven W Kerrigan
- Cardiovascular Infection Research Group, School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
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84
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Hu CMJ, Fang RH, Wang KC, Luk BT, Thamphiwatana S, Dehaini D, Nguyen P, Angsantikul P, Wen CH, Kroll AV, Carpenter C, Ramesh M, Qu V, Patel SH, Zhu J, Shi W, Hofman FM, Chen TC, Gao W, Zhang K, Chien S, Zhang L. Nanoparticle biointerfacing by platelet membrane cloaking. Nature 2015; 526:118-21. [PMID: 26374997 PMCID: PMC4871317 DOI: 10.1038/nature15373] [Citation(s) in RCA: 1136] [Impact Index Per Article: 126.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 08/12/2015] [Indexed: 12/15/2022]
Abstract
Development of functional nanoparticles can be encumbered by unanticipated material properties and biological events, which can affect nanoparticle effectiveness in complex, physiologically relevant systems. Despite the advances in bottom-up nanoengineering and surface chemistry, reductionist functionalization approaches remain inadequate in replicating the complex interfaces present in nature and cannot avoid exposure of foreign materials. Here we report on the preparation of polymeric nanoparticles enclosed in the plasma membrane of human platelets, which are a unique population of cellular fragments that adhere to a variety of disease-relevant substrates. The resulting nanoparticles possess a right-side-out unilamellar membrane coating functionalized with immunomodulatory and adhesion antigens associated with platelets. Compared to uncoated particles, the platelet membrane-cloaked nanoparticles have reduced cellular uptake by macrophage-like cells and lack particle-induced complement activation in autologous human plasma. The cloaked nanoparticles also display platelet-mimicking properties such as selective adhesion to damaged human and rodent vasculatures as well as enhanced binding to platelet-adhering pathogens. In an experimental rat model of coronary restenosis and a mouse model of systemic bacterial infection, docetaxel and vancomycin, respectively, show enhanced therapeutic efficacy when delivered by the platelet-mimetic nanoparticles. The multifaceted biointerfacing enabled by the platelet membrane cloaking method provides a new approach in developing functional nanoparticles for disease-targeted delivery.
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Affiliation(s)
- Che-Ming J Hu
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Ronnie H Fang
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Kuei-Chun Wang
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Brian T Luk
- Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA.,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Soracha Thamphiwatana
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Diana Dehaini
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Phu Nguyen
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Pavimol Angsantikul
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Cindy H Wen
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - Ashley V Kroll
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Cody Carpenter
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Manikantan Ramesh
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Vivian Qu
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Sherrina H Patel
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - Jie Zhu
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - William Shi
- Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA
| | - Florence M Hofman
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Thomas C Chen
- Department of Pathology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
| | - Weiwei Gao
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA
| | - Kang Zhang
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA.,Shiley Eye Institute, University of California, San Diego, La Jolla, California 92093, USA.,Veterans Administration Healthcare System, San Diego, California 92093, USA
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
| | - Liangfang Zhang
- Department of NanoEngineering, University of California, San Diego, La Jolla, California 92093, USA.,Moores Cancer Center, University of California, San Diego, La Jolla, California 92093, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California 92093, USA
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85
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Li Y, Huang X, Li J, Zeng J, Zhu F, Fan W, Hu L. Both GtfA and GtfB are required for SraP glycosylation in Staphylococcus aureus. Curr Microbiol 2015; 69:121-6. [PMID: 24658735 DOI: 10.1007/s00284-014-0563-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 02/02/2014] [Indexed: 10/25/2022]
Abstract
Staphylococcus aureus has been shown to bind to human platelets through a variety of surface molecules, including serine-rich adhesin for platelets (SraP). The SraP mutant strain of S. aureus is significantly impaired in its ability to initiate infection compared with the wild strain. SraP is a cell wall-anchored, glycosylated protein. A previous study revealed that SecY2, Asp1, Asp2, Asp3, and SecA2 in the SraP operon were required for the efficient transport of glycosylated SraP from the cytoplasm to the bacterial cell surface. However, no glycosyltransferase (Gtf) was found to be involved in the glycosylation of SraP. In this study, SraP was found in all of the 55 clinical isolates of S. aureus using a real-time polymerase chain reaction assay. Sequence and phylogenetic analysis showed that GtfA and GtfB in the SraP operon were highly conserved in most of these clinical isolates. Conserved domains analysis revealed that both GtfA and GtfB contained a GT1_GtfA-like domain. Structural homology analysis inferred that they are both Gtfs. We then constructed an in vivo glycosylation system in Escherichia coli using SraP1–743 as the substrate and GtfA and GtfB as the Gtfs. Using this system, we found that GtfA and GtfB were the Gtfs that transferred the N-acetylglucosamine-containing oligosaccharides to the recombinant SraP1–743. Deletion of either one or both of the Gtfs abolished the glycosylation of SraP. In summary, GtfA and GtfB in the SraP operon are highly conserved in most clinical isolates of S. aureus, and both GtfA and GtfB are required for SraP glycosylation.
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86
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The sweet tooth of bacteria: common themes in bacterial glycoconjugates. Microbiol Mol Biol Rev 2015; 78:372-417. [PMID: 25184559 DOI: 10.1128/mmbr.00007-14] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Humans have been increasingly recognized as being superorganisms, living in close contact with a microbiota on all their mucosal surfaces. However, most studies on the human microbiota have focused on gaining comprehensive insights into the composition of the microbiota under different health conditions (e.g., enterotypes), while there is also a need for detailed knowledge of the different molecules that mediate interactions with the host. Glycoconjugates are an interesting class of molecules for detailed studies, as they form a strain-specific barcode on the surface of bacteria, mediating specific interactions with the host. Strikingly, most glycoconjugates are synthesized by similar biosynthesis mechanisms. Bacteria can produce their major glycoconjugates by using a sequential or an en bloc mechanism, with both mechanistic options coexisting in many species for different macromolecules. In this review, these common themes are conceptualized and illustrated for all major classes of known bacterial glycoconjugates, with a special focus on the rather recently emergent field of glycosylated proteins. We describe the biosynthesis and importance of glycoconjugates in both pathogenic and beneficial bacteria and in both Gram-positive and -negative organisms. The focus lies on microorganisms important for human physiology. In addition, the potential for a better knowledge of bacterial glycoconjugates in the emerging field of glycoengineering and other perspectives is discussed.
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87
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Abstract
Given their small size, platelets are emerging as being one of the most important entities in the bloodstream. Not only do they play a key role in maintaining thrombosis and haemostasis, platelets also play a critical role in orchestrating the immune response. Being the first cell at the site of injury, they are perfectly placed to assess the extent of the damage and recruit immune cells as is necessary. As a first line of defence, platelets can act as primitive immune cells themselves by interacting with invading pathogens. A number of platelet receptors have been shown to interact with bacteria either directly or indirectly, involving a plasma protein bridge. This review will discuss the molecular mechanisms that exist between platelets and bacteria and the functional response to the interaction. We will also discuss the importance of considering animal models of disease and the use of physiological shear when studying platelet-bacterial interactions.
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Affiliation(s)
- Steven W Kerrigan
- School of Pharmacy & Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland , Dublin , Ireland
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88
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Hamzeh-Cognasse H, Damien P, Chabert A, Pozzetto B, Cognasse F, Garraud O. Platelets and infections - complex interactions with bacteria. Front Immunol 2015; 6:82. [PMID: 25767472 PMCID: PMC4341565 DOI: 10.3389/fimmu.2015.00082] [Citation(s) in RCA: 157] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/11/2015] [Indexed: 12/29/2022] Open
Abstract
Platelets can be considered sentinels of vascular system due to their high number in the circulation and to the range of functional immunoreceptors they express. Platelets express a wide range of potential bacterial receptors, including complement receptors, FcγRII, Toll-like receptors but also integrins conventionally described in the hemostatic response, such as GPIIb–IIIa or GPIb. Bacteria bind these receptors either directly, or indirectly via fibrinogen, fibronectin, the first complement C1q, the von Willebrand Factor, etc. The fate of platelet-bound bacteria is questioned. Several studies reported the ability of activated platelets to internalize bacteria such as Staphylococcus aureus or Porphyromonas gingivalis, though there is no clue on what happens thereafter. Are they sheltered from the immune system in the cytoplasm of platelets or are they lysed? Indeed, while the presence of phagolysosome has not been demonstrated in platelets, they contain antimicrobial peptides that were shown to be efficient on S. aureus. Besides, the fact that bacteria can bind to platelets via receptors involved in hemostasis suggests that they may induce aggregation; this has indeed been described for Streptococcus sanguinis, S. epidermidis, or C. pneumoniae. On the other hand, platelets are able to display an inflammatory response to an infectious triggering. We, and others, have shown that platelet release soluble immunomodulatory factors upon stimulation by bacterial components. Moreover, interactions between bacteria and platelets are not limited to only these two partners. Indeed, platelets are also essential for the formation of neutrophil extracellular traps by neutrophils, resulting in bacterial clearance by trapping bacteria and concentrating antibacterial factors but in enhancing thrombosis. In conclusion, the platelet–bacteria interplay is a complex game; its fine analysis is complicated by the fact that the inflammatory component adds to the aggregation response.
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Affiliation(s)
| | - Pauline Damien
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Adrien Chabert
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Bruno Pozzetto
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France
| | - Fabrice Cognasse
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France ; Etablissement Français du Sang Auvergne-Loire , Saint-Etienne , France
| | - Olivier Garraud
- GIMAP-EA3064, Université de Lyon , Saint-Etienne , France ; Institut National de la Transfusion Sanguine , Paris , France
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89
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Sundaresan R, Samen U, Ponnuraj K. Structure of KRT4 binding domain of Srr-1 from Streptococcus agalactiae reveals a novel β-sheet complementation. Int J Biol Macromol 2015; 75:97-105. [PMID: 25603146 DOI: 10.1016/j.ijbiomac.2014.12.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Revised: 12/23/2014] [Accepted: 12/24/2014] [Indexed: 10/24/2022]
Abstract
The serine rich repeat protein-1 (Srr-1) is an adhesive protein of Streptococcus agalactiae. It is the first bacterial protein identified to interact with human keratin 4 (K4 or KRT4). Within Srr-1, the residues 311-641 constitute the non-repeat ligand binding region (Srr-1-BR(311-641)). The C-terminal part of Srr-1-BR(311-641), comprising of residues 485-642 (termed Srr-1-K4BD), have been identified to bind to K4. Here we report the crystal structure of recombinant Srr-1-K4BD(485-642) and its possible mode of interaction with K4 through docking studies. The dimeric structure of Srr-1-K4BD(485-642) reveals a novel two way "slide lock" parallel β-sheet complementation where the C-terminal strand of one monomer is positioned anti-parallel to the N-terminal strand of the adjacent monomer and this arrangement is not seen so far in any of the homologous structures. The dimerization of Srr-1-K4BD(485-642) observed both in the crystal structure and in solution suggests that similar domain association could also be possible in in vivo and we propose this association would likely generate a new binding site for another host molecule. It is likely that the adhesin can recognize multiple ligands using its ligand binding sub-domains through their intra and inter domain association with one another.
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Affiliation(s)
- Ramya Sundaresan
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India
| | - Ulrike Samen
- Institute of Microbiology and Biotechnology, University of Ulm, Albert-Einstein-Allee 11 89081, Ulm, Germany
| | - Karthe Ponnuraj
- Centre of Advanced Study in Crystallography and Biophysics, University of Madras, Guindy Campus, Chennai 600 025, India.
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90
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Cell Wall-Anchored Surface Proteins of Staphylococcus aureus: Many Proteins, Multiple Functions. Curr Top Microbiol Immunol 2015; 409:95-120. [PMID: 26667044 DOI: 10.1007/82_2015_5002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Staphylococcus aureus persistently colonizes about 20 % of the population and is intermittently associated with the remainder. The organism can cause superficial skin infections and life-threatening invasive diseases. The surface of the bacterial cell displays a variety of proteins that are covalently anchored to peptidoglycan. They perform many functions including adhesion to host cells and tissues, invasion of non-phagocytic cells, and evasion of innate immune responses. The proteins have been categorized into distinct classes based on structural and functional analysis. Many surface proteins are multifunctional. Cell wall-anchored proteins perform essential functions supporting survival and proliferation during the commensal state and during invasive infections. The ability of cell wall-anchored proteins to bind to desquamated epithelial cells is important during colonization, and the binding to fibrinogen is of particular significance in pathogenesis.
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91
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A conserved domain is crucial for acceptor substrate binding in a family of glucosyltransferases. J Bacteriol 2014; 197:510-7. [PMID: 25404702 DOI: 10.1128/jb.02267-14] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Serine-rich repeat glycoproteins (SRRPs) are highly conserved in streptococci and staphylococci. Glycosylation of SRRPs is important for bacterial adhesion and pathogenesis. Streptococcus agalactiae is the leading cause of bacterial sepsis and meningitis among newborns. Srr2, an SRRP from S. agalactiae strain COH1, has been implicated in bacterial virulence. Four genes (gtfA, gtfB, gtfC, and gtfD) located downstream of srr2 share significant homology with genes involved in glycosylation of other SRRPs. We have shown previously that gtfA and gtfB encode two glycosyltransferases, GtfA and GtfB, that catalyze the transfer of GlcNAc residues to the Srr2 polypeptide. However, the function of other glycosyltransferases in glycosylation of Srr2 is unknown. In this study, we determined that GtfC catalyzed the direct transfer of glucosyl residues to Srr2-GlcNAc. The GtfC crystal structure was solved at 2.7 Å by molecular replacement. Structural analysis revealed a loop region at the N terminus as a putative acceptor substrate binding domain. Deletion of this domain rendered GtfC unable to bind to its substrate Srr2-GlcNAc, concurrently abolished the glycosyltransferase activity of GtfC, and also altered glycosylation of Srr2. Furthermore, deletion of the corresponding regions from GtfC homologs also abolished their substrate binding and enzymatic activity, indicating that this region is functionally conserved. In summary, we have determined that GtfC is important for the glycosylation of Srr2 and identified a conserved loop region that is crucial for acceptor substrate binding from GtfC homologs in streptococci. These findings shed new mechanistic insight into this family of glycosyltransferases.
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92
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Jaglic Z, Desvaux M, Weiss A, Nesse LL, Meyer RL, Demnerova K, Schmidt H, Giaouris E, Sipailiene A, Teixeira P, Kačániová M, Riedel CU, Knøchel S. Surface adhesins and exopolymers of selected foodborne pathogens. MICROBIOLOGY-SGM 2014; 160:2561-2582. [PMID: 25217529 DOI: 10.1099/mic.0.075887-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ability of bacteria to bind different compounds and to adhere to biotic and abiotic surfaces provides them with a range of advantages, such as colonization of various tissues, internalization, avoidance of an immune response, and survival and persistence in the environment. A variety of bacterial surface structures are involved in this process and these promote bacterial adhesion in a more or less specific manner. In this review, we will focus on those surface adhesins and exopolymers in selected foodborne pathogens that are involved mainly in primary adhesion. Their role in biofilm development will also be considered when appropriate. Both the clinical impact and the implications for food safety of such adhesion will be discussed.
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Affiliation(s)
- Zoran Jaglic
- Veterinary Research Institute, Brno, Czech Republic
| | - Mickaël Desvaux
- INRA, UR454 Microbiologie, F-63122 Saint-Genès Champanelle, France
| | - Agnes Weiss
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | | | - Rikke L Meyer
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, DK-8000 Aarhus C, Denmark
| | - Katerina Demnerova
- Institute of Chemical Technology, Faculty of Food and Biochemical Technology, Department of Biochemistry and Microbiology, Technicka 5, Prague, 166 28, Czech Republic
| | - Herbert Schmidt
- Department of Food Microbiology, Institute of Food Science and Biotechnology, University of Hohenheim, Garbenstrasse 28, 70599 Stuttgart, Germany
| | - Efstathios Giaouris
- Department of Food Science and Nutrition, Faculty of the Environment, University of the Aegean, 81400 Myrina, Lemnos Island, Greece
| | | | - Pilar Teixeira
- CEB - Centre of Biological Engineering, University of Minho, Braga, Portugal
| | | | - Christian U Riedel
- Institute of Microbiology and Biotechnology, University of Ulm, Ulm, Germany
| | - Susanne Knøchel
- Department of Food Science, University of Copenhagen, Rolighedsvej 30, Frederiksberg C 1958, Denmark
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93
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Ruiz L, Hevia A, Bernardo D, Margolles A, Sánchez B. Extracellular molecular effectors mediating probiotic attributes. FEMS Microbiol Lett 2014; 359:1-11. [DOI: 10.1111/1574-6968.12576] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 08/04/2014] [Accepted: 08/11/2014] [Indexed: 12/29/2022] Open
Affiliation(s)
- Lorena Ruiz
- Department of Microbiology; University College Cork; Cork Ireland
| | - Arancha Hevia
- Department of Microbiology and Biochemistry of Dairy Products; Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC); Asturias Spain
| | - David Bernardo
- Antigen Presentation Research Group; Imperial College London; Harrow UK
| | - Abelardo Margolles
- Department of Microbiology and Biochemistry of Dairy Products; Instituto de Productos Lácteos de Asturias - Consejo Superior de Investigaciones Científicas (IPLA-CSIC); Asturias Spain
| | - Borja Sánchez
- Nutrition and Bromatology Group; Department of Analytical and Food Chemistry; Food Science and Technology Faculty; University of Vigo; Ourense Spain
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94
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Yang YH, Jiang YL, Zhang J, Wang L, Bai XH, Zhang SJ, Ren YM, Li N, Zhang YH, Zhang Z, Gong Q, Mei Y, Xue T, Zhang JR, Chen Y, Zhou CZ. Structural insights into SraP-mediated Staphylococcus aureus adhesion to host cells. PLoS Pathog 2014; 10:e1004169. [PMID: 24901708 PMCID: PMC4047093 DOI: 10.1371/journal.ppat.1004169] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 04/22/2014] [Indexed: 11/18/2022] Open
Abstract
Staphylococcus aureus, a Gram-positive bacterium causes a number of devastating human diseases, such as infective endocarditis, osteomyelitis, septic arthritis and sepsis. S. aureus SraP, a surface-exposed serine-rich repeat glycoprotein (SRRP), is required for the pathogenesis of human infective endocarditis via its ligand-binding region (BR) adhering to human platelets. It remains unclear how SraP interacts with human host. Here we report the 2.05 Å crystal structure of the BR of SraP, revealing an extended rod-like architecture of four discrete modules. The N-terminal legume lectin-like module specifically binds to N-acetylneuraminic acid. The second module adopts a β-grasp fold similar to Ig-binding proteins, whereas the last two tandem repetitive modules resemble eukaryotic cadherins but differ in calcium coordination pattern. Under the conditions tested, small-angle X-ray scattering and molecular dynamic simulation indicated that the three C-terminal modules function as a relatively rigid stem to extend the N-terminal lectin module outwards. Structure-guided mutagenesis analyses, in addition to a recently identified trisaccharide ligand of SraP, enabled us to elucidate that SraP binding to sialylated receptors promotes S. aureus adhesion to and invasion into host epithelial cells. Our findings have thus provided novel structural and functional insights into the SraP-mediated host-pathogen interaction of S. aureus.
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Affiliation(s)
- Yi-Hu Yang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Yong-Liang Jiang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Juan Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Lei Wang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Xiao-Hui Bai
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Shi-Jie Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Yan-Min Ren
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Na Li
- Shanghai Institute of Biochemistry and Cell Biology, Shanghai, China
| | - Yong-Hui Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Zhiyong Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Qingguo Gong
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Yide Mei
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Ting Xue
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, People's Republic of China
| | - Yuxing Chen
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
- * E-mail: (YC); (CZZ)
| | - Cong-Zhao Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale and School of Life Sciences, University of Science and Technology of China, Hefei Anhui, People's Republic of China
- * E-mail: (YC); (CZZ)
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95
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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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96
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Wang NY, Patras KA, Seo HS, Cavaco CK, Rösler B, Neely MN, Sullam PM, Doran KS. Group B streptococcal serine-rich repeat proteins promote interaction with fibrinogen and vaginal colonization. J Infect Dis 2014; 210:982-91. [PMID: 24620021 DOI: 10.1093/infdis/jiu151] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Group B streptococcus (GBS) can cause severe disease in susceptible hosts, including newborns, pregnant women, and the elderly. GBS serine-rich repeat (Srr) surface glycoproteins are important adhesins/invasins in multiple host tissues, including the vagina. However, exact molecular mechanisms contributing to their importance in colonization are unknown. We have recently determined that Srr proteins contain a fibrinogen-binding region (BR) and hypothesize that Srr-mediated fibrinogen binding may contribute to GBS cervicovaginal colonization. In this study, we observed that fibrinogen enhanced wild-type GBS attachment to cervical and vaginal epithelium, and that this was dependent on Srr1. Moreover, purified Srr1-BR peptide bound directly to host cells, and peptide administration in vivo reduced GBS recovery from the vaginal tract. Furthermore, a GBS mutant strain lacking only the Srr1 "latching" domain exhibited decreased adherence in vitro and decreased persistence in a mouse model of GBS vaginal colonization, suggesting the importance of Srr-fibrinogen interactions in the female reproductive tract.
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Affiliation(s)
- Nai-Yu Wang
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Kathryn A Patras
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Ho Seong Seo
- Division of Infectious Diseases, Veteran Affairs Medical Center and the University of California San Francisco, California Radiation Biotechnology Research Division, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Republic of Korea
| | - Courtney K Cavaco
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Berenice Rösler
- Department of Biology and Center for Microbial Sciences, San Diego State University
| | - Melody N Neely
- Department of Immunology and Microbiology, School of Medicine, Wayne State University, Detroit, Michigan
| | - Paul M Sullam
- Division of Infectious Diseases, Veteran Affairs Medical Center and the University of California San Francisco, California
| | - Kelly S Doran
- Department of Biology and Center for Microbial Sciences, San Diego State University Department of Pediatrics, University of California San Diego School of Medicine, La Jolla
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97
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Christiansen MT, Kaas RS, Chaudhuri RR, Holmes MA, Hasman H, Aarestrup FM. Genome-wide high-throughput screening to investigate essential genes involved in methicillin-resistant Staphylococcus aureus Sequence Type 398 survival. PLoS One 2014; 9:e89018. [PMID: 24563689 PMCID: PMC3923074 DOI: 10.1371/journal.pone.0089018] [Citation(s) in RCA: 19] [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: 10/30/2013] [Accepted: 01/14/2014] [Indexed: 02/06/2023] Open
Abstract
Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) Sequence Type 398 (ST398) is an opportunistic pathogen that is able to colonize and cause disease in several animal species including humans. To better understand the adaptation, evolution, transmission and pathogenic capacity, further investigations into the importance of the different genes harboured by LA-MRSA ST398 are required. In this study we generated a genome-wide transposon mutant library in an LA-MRSA ST398 isolate to evaluate genes important for bacterial survival in laboratory and host-specific environments. The transposon mutant library consisted of approximately 1 million mutants with around 140,000 unique insertion sites and an average number of unique inserts per gene of 44.8. We identified LA-MRSA ST398 essential genes comparable to other high-throughput S. aureus essential gene studies. As ST398 is the most common MRSA isolated from pigs, the transposon mutant library was screened in whole porcine blood. Twenty-four genes were specifically identified as important for bacterial survival in porcine blood. Mutations in 23 of these genes resulted in attenuated bacterial fitness. Seven of the 23 genes were of unknown function, whereas 16 genes were annotated with functions predominantly related to carbon metabolism, pH shock and a variety of regulations and only indirectly to virulence factors. Mutations in one gene of unknown function resulted in a hypercompetitive mutant. Further evaluation of these genes is required to determine their specific relevance in blood survival.
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Affiliation(s)
- Mette T. Christiansen
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
- * E-mail: (MTC); (FMA)
| | - Rolf S. Kaas
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Roy R. Chaudhuri
- Department of Veterinary Medicine, University of Cambridge, Cambridge, England, United Kingdom
| | - Mark A. Holmes
- Department of Veterinary Medicine, University of Cambridge, Cambridge, England, United Kingdom
| | - Henrik Hasman
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
| | - Frank M. Aarestrup
- National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark
- * E-mail: (MTC); (FMA)
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98
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Foster TJ, Geoghegan JA, Ganesh VK, Höök M. Adhesion, invasion and evasion: the many functions of the surface proteins of Staphylococcus aureus. Nat Rev Microbiol 2014; 12:49-62. [PMID: 24336184 DOI: 10.1038/nrmicro3161] [Citation(s) in RCA: 933] [Impact Index Per Article: 93.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Staphylococcus aureus is an important opportunistic pathogen and persistently colonizes about 20% of the human population. Its surface is 'decorated' with proteins that are covalently anchored to the cell wall peptidoglycan. Structural and functional analysis has identified four distinct classes of surface proteins, of which microbial surface component recognizing adhesive matrix molecules (MSCRAMMs) are the largest class. These surface proteins have numerous functions, including adhesion to and invasion of host cells and tissues, evasion of immune responses and biofilm formation. Thus, cell wall-anchored proteins are essential virulence factors for the survival of S. aureus in the commensal state and during invasive infections, and targeting them with vaccines could combat S. aureus infections.
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Affiliation(s)
- Timothy J Foster
- Microbiology Department, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
| | - Joan A Geoghegan
- Microbiology Department, Moyne Institute of Preventive Medicine, Trinity College, Dublin 2, Ireland
| | - Vannakambadi K Ganesh
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030, USA
| | - Magnus Höök
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A & M University Health Science Center, Houston, Texas 77030, USA
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Sait M, Livingstone M, Clark EM, Wheelhouse N, Spalding L, Markey B, Magnino S, Lainson FA, Myers GSA, Longbottom D. Genome sequencing and comparative analysis of three Chlamydia pecorum strains associated with different pathogenic outcomes. BMC Genomics 2014; 15:23. [PMID: 24417976 PMCID: PMC3932018 DOI: 10.1186/1471-2164-15-23] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 01/06/2014] [Indexed: 11/17/2022] Open
Abstract
Background Chlamydia pecorum is the causative agent of a number of acute diseases, but most often causes persistent, subclinical infection in ruminants, swine and birds. In this study, the genome sequences of three C. pecorum strains isolated from the faeces of a sheep with inapparent enteric infection (strain W73), from the synovial fluid of a sheep with polyarthritis (strain P787) and from a cervical swab taken from a cow with metritis (strain PV3056/3) were determined using Illumina/Solexa and Roche 454 genome sequencing. Results Gene order and synteny was almost identical between C. pecorum strains and C. psittaci. Differences between C. pecorum and other chlamydiae occurred at a number of loci, including the plasticity zone, which contained a MAC/perforin domain protein, two copies of a >3400 amino acid putative cytotoxin gene and four (PV3056/3) or five (P787 and W73) genes encoding phospholipase D. Chlamydia pecorum contains an almost intact tryptophan biosynthesis operon encoding trpABCDFR and has the ability to sequester kynurenine from its host, however it lacks the genes folA, folKP and folB required for folate metabolism found in other chlamydiae. A total of 15 polymorphic membrane proteins were identified, belonging to six pmp families. Strains possess an intact type III secretion system composed of 18 structural genes and accessory proteins, however a number of putative inc effector proteins widely distributed in chlamydiae are absent from C. pecorum. Two genes encoding the hypothetical protein ORF663 and IncA contain variable numbers of repeat sequences that could be associated with persistence of infection. Conclusions Genome sequencing of three C. pecorum strains, originating from animals with different disease manifestations, has identified differences in ORF663 and pseudogene content between strains and has identified genes and metabolic traits that may influence intracellular survival, pathogenicity and evasion of the host immune system. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-23) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - David Longbottom
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, UK.
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Heo SM, Ruhl S, Scannapieco FA. Implications of salivary protein binding to commensal and pathogenic bacteria. J Oral Biosci 2013; 55:169-174. [PMID: 24707190 PMCID: PMC3974197 DOI: 10.1016/j.job.2013.06.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
An important function of salivary proteins is to interact with microorganisms that enter the oral cavity. For some microbes, these interactions promote microbial colonization. For others, these interactions are deleterious and result in the elimination of the microbe from the mouth, This paper reviews recent studies of the interaction of salivary proteins with two model bacteria; the commensal species Streptococcus gordonii, and the facultative pathogen Staphylococcus aureus. These organisms selectively interact with a variety of salivary proteins to influence important functions such as bacterial adhesion to surfaces, evasion of host defense, bacterial nutrition and metabolism and gene expression.
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Affiliation(s)
- Seok-Mo Heo
- Department of Periodontology, School of Dentistry, Chonbuk National University, Jeonju, Republic of Korea
| | | | - Frank A. Scannapieco
- Corresponding author: Department of Oral Biology, School of Dental Medicine, University at Buffalo, The State University of New York, Foster Hall, Buffalo, New York 14214,
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