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Cox D. Sepsis - it is all about the platelets. Front Immunol 2023; 14:1210219. [PMID: 37350961 PMCID: PMC10282552 DOI: 10.3389/fimmu.2023.1210219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 05/19/2023] [Indexed: 06/24/2023] Open
Abstract
Sepsis is accompanied by thrombocytopenia and the severity of the thrombocytopenia is associated with mortality. This thrombocytopenia is characteristic of disseminated intravascular coagulation (DIC), the sepsis-associated coagulopathy. Many of the pathogens, both bacterial and viral, that cause sepsis also directly activate platelets, which suggests that pathogen-induced platelet activation leads to systemic thrombosis and drives the multi-organ failure of DIC. In this paper we review the mechanisms of platelet activation by pathogens and the evidence for a role for anti-platelet agents in the management of sepsis.
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Affiliation(s)
- Dermot Cox
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
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2
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Braï MA, Hannachi N, El Gueddari N, Baudoin JP, Dahmani A, Lepidi H, Habib G, Camoin-Jau L. The Role of Platelets in Infective Endocarditis. Int J Mol Sci 2023; 24:ijms24087540. [PMID: 37108707 PMCID: PMC10143005 DOI: 10.3390/ijms24087540] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 04/02/2023] [Accepted: 04/15/2023] [Indexed: 04/29/2023] Open
Abstract
Over the last decade, the incidence of infective endocarditis (IE) has increased, with a change in the frequency of causative bacteria. Early evidence has substantially demonstrated the crucial role of bacterial interaction with human platelets, with no clear mechanistic characterization in the pathogenesis of IE. The pathogenesis of endocarditis is so complex and atypical that it is still unclear how and why certain bacterial species will induce the formation of vegetation. In this review, we will analyze the key role of platelets in the physiopathology of endocarditis and in the formation of vegetation, depending on the bacterial species. We provide a comprehensive outline of the involvement of platelets in the host immune response, investigate the latest developments in platelet therapy, and discuss prospective research avenues for solving the mechanistic enigma of bacteria-platelet interaction for preventive and curative medicine.
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Affiliation(s)
- Mustapha Abdeljalil Braï
- IRD, APHM, MEPHI, IHU Méditerranée Infection, Aix Marseille University, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
- IHU Méditerranée Infection, Boulevard Jean Moulin, 13385 Marseille, France
| | - Nadji Hannachi
- Laboratoire de Biopharmacie et Pharmacotechnie, Faculté de Médecine, Université Ferhat Abbas Sétif I, Sétif 19000, Algeria
| | - Nabila El Gueddari
- IRD, APHM, MEPHI, IHU Méditerranée Infection, Aix Marseille University, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
- Service de Chirurgie Cardiaque, Hôpital de la Timone, APHM, Boulevard Jean-Moulin, 13385 Marseille, France
| | - Jean-Pierre Baudoin
- IRD, APHM, MEPHI, IHU Méditerranée Infection, Aix Marseille University, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
- IHU Méditerranée Infection, Boulevard Jean Moulin, 13385 Marseille, France
| | - Abderrhamane Dahmani
- IRD, APHM, MEPHI, IHU Méditerranée Infection, Aix Marseille University, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
- IHU Méditerranée Infection, Boulevard Jean Moulin, 13385 Marseille, France
| | - Hubert Lepidi
- IRD, APHM, MEPHI, IHU Méditerranée Infection, Aix Marseille University, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
- Service d'Anatomo-Pathologie, Hôpital de la Timone, APHM, Boulevard Jean-Moulin, 13385 Marseille, France
| | - Gilbert Habib
- IRD, APHM, MEPHI, IHU Méditerranée Infection, Aix Marseille University, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
- Service de Cardiologie, Hôpital de la Timone, APHM, Boulevard Jean-Moulin, 13385 Marseille, France
| | - Laurence Camoin-Jau
- IRD, APHM, MEPHI, IHU Méditerranée Infection, Aix Marseille University, 19-21 Boulevard Jean Moulin, 13005 Marseille, France
- Laboratoire d'Hématologie, Hôpital de la Timone, APHM, Boulevard Jean-Moulin, 13385 Marseille, France
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Yadav VK, Singh PK, Agarwal V, Singh SK. Crosstalk between Platelet and Bacteria: A Therapeutic Prospect. Curr Pharm Des 2019; 25:4041-4052. [PMID: 31553286 DOI: 10.2174/1381612825666190925163347] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 09/13/2019] [Indexed: 12/16/2022]
Abstract
Platelets are typically recognized for their roles in the maintenance of hemostasis and vascular wall repair to reduce blood loss. Beyond hemostasis, platelets also play a critical role in pathophysiological conditions like atherosclerosis, stroke, thrombosis, and infections. During infection, platelets interact directly and indirectly with bacteria through a wide range of cellular and molecular mechanisms. Platelet surface receptors such as GPIbα, FcγRIIA, GPIIbIIIa, and TLRs, etc. facilitate direct interaction with bacterial cells. Besides, the indirect interaction between platelet and bacteria involves host plasma proteins such as von Willebrand Factor (vWF), fibronectin, IgG, and fibrinogen. Bacterial cells induce platelet activation, aggregation, and thrombus formation in the microvasculature. The activated platelets induce the Neutrophil Extracellular Traps (NETs) formation, which further contribute to thrombosis. Thus, platelets are extensively anticipated as vital immune modulator cells during infection, which may further lead to cardiovascular complications. In this review, we cover the interaction mechanisms between platelets and bacteria that may lead to the development of thrombotic disorders. Platelet receptors and other host molecules involved in such interactions can be used to develop new therapeutic strategies to combat against infection-induced cardiovascular complications. In addition, we highlight other receptor and enzyme targets that may further reduce infection-induced platelet activation and various pathological conditions.
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Affiliation(s)
- Vivek K Yadav
- Department of Biotechnology Motilal Nehru National Institute of Technology Allahabad, Prayagraj, India
| | - Pradeep K Singh
- Department of Biotechnology Motilal Nehru National Institute of Technology Allahabad, Prayagraj, India
| | - Vishnu Agarwal
- Department of Biotechnology Motilal Nehru National Institute of Technology Allahabad, Prayagraj, India
| | - Sunil K Singh
- Department of Animal Sciences, Central University of Punjab, Bathinda, Punjab, India
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4
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Kerrigan SW, Devine T, Fitzpatrick G, Thachil J, Cox D. Early Host Interactions That Drive the Dysregulated Response in Sepsis. Front Immunol 2019; 10:1748. [PMID: 31447831 PMCID: PMC6691039 DOI: 10.3389/fimmu.2019.01748] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Accepted: 07/10/2019] [Indexed: 01/18/2023] Open
Abstract
Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. While many individual cells and systems in the body are involved in driving the excessive and sometimes sustained host response, pathogen engagement with endothelial cells and platelets early in sepsis progression, are believed to be key. Significant progress has been made in establishing key molecular interactions between platelets and pathogens and endothelial cells and pathogens. This review will explore the growing number of compensatory connections between bacteria and viruses with platelets and endothelial cells and how a better understanding of these interactions are informing the field of potential novel ways to treat the dysregulated host response during sepsis.
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Affiliation(s)
- Steven W Kerrigan
- Cardiovascular Infection Research Group, Royal College of Surgeons in Ireland, Dublin, Ireland.,School of Pharmacy, Royal College of Surgeons in Ireland, Dublin, Ireland.,Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Tatyana Devine
- Cardiovascular Infection Research Group, Royal College of Surgeons in Ireland, Dublin, Ireland.,Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Glenn Fitzpatrick
- Cardiovascular Infection Research Group, Royal College of Surgeons in Ireland, Dublin, Ireland.,School of Pharmacy, Royal College of Surgeons in Ireland, Dublin, Ireland.,Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Jecko Thachil
- Department of Haematology, Central Manchester University Hospitals NHS Foundation Trust, Manchester, United Kingdom
| | - Dermot Cox
- Cardiovascular Infection Research Group, Royal College of Surgeons in Ireland, Dublin, Ireland.,Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Irish Centre for Vascular Biology, Royal College of Surgeons in Ireland, Dublin, Ireland
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5
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Bensing BA, Li L, Yakovenko O, Wong M, Barnard KN, Iverson TM, Lebrilla CB, Parrish CR, Thomas WE, Xiong Y, Sullam PM. Recognition of specific sialoglycan structures by oral streptococci impacts the severity of endocardial infection. PLoS Pathog 2019; 15:e1007896. [PMID: 31233555 PMCID: PMC6611644 DOI: 10.1371/journal.ppat.1007896] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 07/05/2019] [Accepted: 06/05/2019] [Indexed: 11/18/2022] Open
Abstract
Streptococcus gordonii and Streptococcus sanguinis are primary colonizers of the tooth surface. Although generally non-pathogenic in the oral environment, they are a frequent cause of infective endocarditis. Both streptococcal species express a serine-rich repeat surface adhesin that mediates attachment to sialylated glycans on mucin-like glycoproteins, but the specific sialoglycan structures recognized can vary from strain to strain. Previous studies have shown that sialoglycan binding is clearly important for aortic valve infections caused by some S. gordonii, but this process did not contribute to the virulence of a strain of S. sanguinis. However, these streptococci can bind to different subsets of sialoglycan structures. Here we generated isogenic strains of S. gordonii that differ only in the type and range of sialoglycan structures to which they adhere and examined whether this rendered them more or less virulent in a rat model of endocarditis. The findings indicate that the recognition of specific sialoglycans can either enhance or diminish pathogenicity. Binding to sialyllactosamine reduces the initial colonization of mechanically-damaged aortic valves, whereas binding to the closely-related trisaccharide sialyl T-antigen promotes higher bacterial densities in valve tissue 72 hours later. A surprising finding was that the initial attachment of streptococci to aortic valves was inversely proportional to the affinity of each strain for platelets, suggesting that binding to platelets circulating in the blood may divert bacteria away from the endocardial surface. Importantly, we found that human and rat platelet GPIbα (the major receptor for S. gordonii and S. sanguinis on platelets) display similar O-glycan structures, comprised mainly of a di-sialylated core 2 hexasaccharide, although the rat GPIbα has a more heterogenous composition of modified sialic acids. The combined results suggest that streptococcal interaction with a minor O-glycan on GPIbα may be more important than the over-all affinity for GPIbα for pathogenic effects. Infective endocarditis (IE) is a life-threatening infection of heart valves, and streptococci that normally reside in the mouth are a leading cause of this disease. Some oral streptococcal species express a protein on their surface that enables attachment to glycan (sugar) modifications on saliva proteins, an interaction that may be important for colonization of the tooth and other oral surfaces. These "Siglec-like adhesins" are hypervariable in the type and number of glycan structures they bind, ranging from just one to more than six of the structures displayed on the saliva proteins. If streptococci enter into the bloodstream, the Siglec-like adhesin can mediate attachment to similar glycans that decorate platelet or plasma proteins, which can impact the overall virulence of the organism. This study highlights how recognition of a specific type of glycan structure can cause a generally beneficial or neutral microbe to create damage to specific tissues—in this case the heart valves, illustrating one means by which commensal bacteria can become opportunistic or accidental pathogens. The findings further indicate that certain glycan-binding streptococci among the oral microbiota may be predisposed to produce infective endocarditis.
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Affiliation(s)
- Barbara A. Bensing
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, California, United States of America
- * E-mail:
| | - Liang Li
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Olga Yakovenko
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Maurice Wong
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Karen N. Barnard
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - T. M. Iverson
- Departments of Pharmacology and Biochemistry, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Carlito B. Lebrilla
- Department of Chemistry, University of California, Davis, California, United States of America
| | - Colin R. Parrish
- Baker Institute for Animal Health, Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Wendy E. Thomas
- Department of Bioengineering, University of Washington, Seattle, Washington, United States of America
| | - Yan Xiong
- Los Angeles Biomedical Research Institute, Harbor-UCLA Medical Center, Torrance, California, United States of America
- David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Paul M. Sullam
- Department of Medicine, San Francisco Veterans Affairs Medical Center and University of California, San Francisco, California, United States of America
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6
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Hazell G, May PW, Taylor P, Nobbs AH, Welch CC, Su B. Studies of black silicon and black diamond as materials for antibacterial surfaces. Biomater Sci 2018; 6:1424-1432. [PMID: 29611852 DOI: 10.1039/c8bm00107c] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
'Black silicon' (bSi) samples with surfaces covered in nanoneedles of varying length, areal density and sharpness, have been fabricated using a plasma etching process. These nanostructures were then coated with a conformal uniform layer of diamond using hot filament chemical vapour deposition to produce 'black diamond' (bD) surfaces. The effectiveness of these bSi and bD surfaces in killing Gram-negative (E. coli) and Gram-positive (S. gordonii) bacteria was investigated by culturing the bacteria on the surfaces for a set time and then measuring the live-to-dead ratio. All the nanostructured surfaces killed E. coli at a significantly higher rate than the respective flat Si or diamond control samples. The length of the needles was found to be less important than their separation, i.e. areal density. This is consistent with a model for mechanical bacteria death based on the stretching and disruption of the cell membrane, enhanced by the cells motility on the surfaces. In contrast, S. gordonii were unaffected by the nanostructured surfaces, possibly due to their smaller size, thicker cell membrane and/or their lack of motility.
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Affiliation(s)
- G Hazell
- Bristol Dental School, University of Bristol, Lower Maudlin Street, Bristol, BS1 2LY, UK
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7
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Macrophage Polarization Alters Postphagocytosis Survivability of the Commensal Streptococcus gordonii. Infect Immun 2018; 86:IAI.00858-17. [PMID: 29229734 DOI: 10.1128/iai.00858-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Accepted: 12/05/2017] [Indexed: 12/22/2022] Open
Abstract
Oral streptococci are generally considered commensal organisms; however, they are becoming recognized as important associate pathogens during the development of periodontal disease as well as being associated with several systemic diseases, including as a causative agent of infective endocarditis. An important virulence determinant of these bacteria is an ability to evade destruction by phagocytic cells, yet how this subversion occurs is mostly unknown. Using Streptococcus gordonii as a model commensal oral streptococcus that is also associated with disease, we find that resistance to reactive oxygen species (ROS) with an active ability to damage phagosomes allows the bacterium to avoid destruction within macrophages. This ability to survive relies not only on the ROS resistance capabilities of the bacterium but also on ROS production by macrophages, with both being required for maximal survival of internalized bacteria. Importantly, we also show that this dependence on ROS production by macrophages for resistance has functional significance: S. gordonii intracellular survival increases when macrophages are polarized toward an activated (M1) profile, which is known to result in prolonged phagosomal ROS production compared to that of alternatively (M2) polarized macrophages. We additionally find evidence of the bacterium being capable of both delaying the maturation of and damaging phagosomes. Taken together, these results provide essential insights regarding the mechanisms through which normally commensal oral bacteria can contribute to both local and systemic inflammatory disease.
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8
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Haworth JA, Mears RG, Jenkinson HF, Kerrigan SW, Nobbs AH. Oral hygiene as a risk factor in infective endocarditis. ACTA ACUST UNITED AC 2017. [DOI: 10.12968/denu.2017.44.9.877] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jennifer A Haworth
- Academic Clinical Lecturer, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
| | - Richard G Mears
- General Dental Practitioner, Combe Road Dental Practice, 6 Combe Road, Portishead, BS20 6BJ and Clinical Teaching Fellow, Restorative Dentistry, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
| | - Howard F Jenkinson
- Professor of Oral Microbiology, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
| | - Steve W Kerrigan
- Senior Lecturer in Pharmacology, Royal College of Surgeons in Ireland, 123 St Stephen's Green, Dublin 2, Ireland
| | - Angela H Nobbs
- Senior Lecturer in Oral Microbiology, Bristol Dental School, University of Bristol, Lower Maudlin Street, BS1 2LY, Bristol, UK
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Affiliation(s)
- Angela Nobbs
- a School of Oral and Dental Sciences, University of Bristol , Bristol , UK
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Haworth JA, Jenkinson HF, Petersen HJ, Back CR, Brittan JL, Kerrigan SW, Nobbs AH. Concerted functions of Streptococcus gordonii surface proteins PadA and Hsa mediate activation of human platelets and interactions with extracellular matrix. Cell Microbiol 2017; 19:e12667. [PMID: 27616700 PMCID: PMC5574023 DOI: 10.1111/cmi.12667] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 08/23/2016] [Accepted: 09/07/2016] [Indexed: 12/17/2022]
Abstract
A range of Streptococcus bacteria are able to interact with blood platelets to form a thrombus (clot). Streptococcus gordonii is ubiquitous within the human oral cavity and amongst the common pathogens isolated from subjects with infective endocarditis. Two cell surface proteins, Hsa and Platelet adherence protein A (PadA), in S. gordonii mediate adherence and activation of platelets. In this study, we demonstrate that PadA binds activated platelets and that an NGR (Asparagine-Glycine-Arginine) motif within a 657 amino acid residue N-terminal fragment of PadA is responsible for this, together with two other integrin-like recognition motifs RGT and AGD. PadA also acts in concert with Hsa to mediate binding of S. gordonii to cellular fibronectin and vitronectin, and to promote formation of biofilms. Evidence is presented that PadA and Hsa are each reliant on the other's active presentation on the bacterial cell surface, suggesting cooperativity in functions impacting both colonization and pathogenesis.
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Affiliation(s)
| | | | | | | | - Jane L. Brittan
- School of Oral and Dental SciencesUniversity of BristolBristolUK
| | - Steve W. Kerrigan
- Cardiovascular Infection GroupRoyal College of Surgeons in IrelandDublin 2Ireland
| | - Angela H. Nobbs
- School of Oral and Dental SciencesUniversity of BristolBristolUK
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Antibodies Targeting Hsa and PadA Prevent Platelet Aggregation and Protect Rats against Experimental Endocarditis Induced by Streptococcus gordonii. Infect Immun 2016; 84:3557-3563. [PMID: 27736784 DOI: 10.1128/iai.00810-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 09/22/2016] [Indexed: 01/24/2023] Open
Abstract
Streptococcus gordonii and related species of oral viridans group streptococci (VGS) are common etiological agents of infective endocarditis (IE). We explored vaccination as a strategy to prevent VGS-IE, using a novel antigen-presenting system based on non-genetically modified Lactococcus lactis displaying vaccinogens on its surface. Hsa and PadA are surface-located S. gordonii proteins implicated in platelet adhesion and aggregation, which are key steps in the pathogenesis of IE. This function makes them ideal targets for vaccination against VGS-IE. In the present study, we report the use of nonliving L. lactis displaying at its surface the N-terminal region of Hsa or PadA by means of the cell wall binding domain of Lactobacillus casei A2 phage lysine LysA2 (Hsa-LysA2 and PadA-LysA2, respectively) and investigation of their ability to elicit antibodies in rats and to protect them from S. gordonii experimental IE. Immunized and control animals with catheter-induced sterile aortic valve vegetations were inoculated with 106 CFU of S. gordonii The presence of IE was evaluated 24 h later. Immunization of rats with L. lactis Hsa-LysA2, L. lactis PadA-LysA2, or both protected 6/11 (55%), 6/11 (55%), and 11/12 (91%) animals, respectively, from S. gordonii IE (P < 0.05 versus controls). Protection correlated with the induction of high levels of functional antibodies against both Hsa and PadA that delayed or totally inhibited platelet aggregation by S. gordonii These results support the value of L. lactis as a system for antigen delivery and of Hsa and PadA as promising candidates for a vaccine against VGS-IE.
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12
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Son YM, Jeong DH, Park HJ, Rhee MH. The inhibitory activity of ginsenoside Rp4 in adenosine diphosphate-induced platelet aggregation. J Ginseng Res 2016; 41:96-102. [PMID: 28123327 PMCID: PMC5223082 DOI: 10.1016/j.jgr.2016.01.003] [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: 12/04/2015] [Revised: 01/15/2016] [Accepted: 01/26/2016] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Korean ginseng, Panax ginseng Meyer, has been used as a traditional oriental medicine to treat illness and promote health for several thousand years. Ginsenosides are the main constituents for the pharmacological effects of P. ginseng. Since several ginsenosides, including ginsenoside (G)-Rg3 and G-Rp1, have reported antiplatelet activity, here we investigate the ability of G-Rp4 to modulate adenosine diphosphate (ADP)-induced platelet aggregation. The ginsenoside Rp4, a similar chemical structure of G-Rp1, was prepared from G-Rg1 by chemical modification. METHODS To examine the effects of G-Rp4 on platelet activation, we performed several experiments, including antiplatelet ability, the modulation of intracellular calcium concentration, and P-selectin expression. In addition, we examined the activation of integrin αIIbβ3 and the phosphorylation of signaling molecules using fibrinogen binding assay and immunoblotting in rat washed platelets. RESULTS G-Rp4 inhibited ADP-induced platelet aggregation in a dose-dependent manner. We found that G-Rp4 decreased calcium mobilization and P-selectin expression in ADP-activated platelets. Moreover, fibrinogen binding to integrin αIIbβ3 by ADP was attenuated in G-Rp4-treated platelets. G-Rp4 significantly attenuated phosphorylation of extracellular signal-regulated protein kinases 1 and 2, p38, and c-Jun N-terminal kinase, as well as protein kinase B, phosphatidylinositol 3-kinase, and phospholipase C-γ phosphorylations. CONCLUSION G-Rp4 significantly inhibited ADP-induced platelet aggregation and this is mediated via modulating the intracellular signaling molecules. These results indicate that G-Rp4 could be a potential candidate as a therapeutic agent against platelet-related cardiovascular diseases.
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Affiliation(s)
- Young-Min Son
- Laboratory of Veterinary Physiology and Cell Signaling, College of Veterinary Medicine, Kyungpook National University, Daegu, Korea
| | - Da-Hye Jeong
- Laboratory of Veterinary Physiology and Cell Signaling, College of Veterinary Medicine, Kyungpook National University, Daegu, Korea
| | - Hwa-Jin Park
- Department of Biomedical Laboratory Science, College of Biomedical Science, Inje University, Gimhae, Korea
| | - Man-Hee Rhee
- Laboratory of Veterinary Physiology and Cell Signaling, College of Veterinary Medicine, Kyungpook National University, Daegu, Korea
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13
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Identification of PblB mediating galactose-specific adhesion in a successful Streptococcus pneumoniae clone. Sci Rep 2015; 5:12265. [PMID: 26193794 PMCID: PMC4508584 DOI: 10.1038/srep12265] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 06/19/2015] [Indexed: 12/27/2022] Open
Abstract
The pneumococcal genome is variable and there are minimal data on the influence of the accessory genome on phenotype. Pneumococcal serotype 14 sequence type (ST) 46 had been the most prevalent clone causing pneumonia in children in Taiwan. A microarray was constructed using the genomic DNA of a clinical strain (NTUH-P15) of serotype 14 ST46. Using DNA hybridization, genomic variations in NTUH-P15 were compared to those of 3 control strains. Microarray analysis identified 7 genomic regions that had significant increases in hybridization signals in the NTUH-P15 strain compared to control strains. One of these regions encoded PblB, a phage-encoded virulence factor implicated (in Streptococcus mitis) in infective endocarditis. The isogenic pblB mutant decreased adherence to A549 human lung epithelial cell compared to wild-type NTUH-P15 strain (P = 0.01). Complementation with pblB restored the adherence. PblB is predicted to contain a galactose-binding domain-like region. Preincubation of NTUH-P15 with D-galactose resulted in decreases of adherence to A549 cell in a dose-dependent manner. Challenge of mice with NTUH-P15, isogenic pblB mutant and pblB complementation strains determined that PblB was required for bacterial persistence in the nasopharynx and lung. PblB, as an adhesin mediating the galactose-specific adhesion activity of pneumococci, promote pneumococcal clonal success.
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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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