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Host blood proteins as bridging ligand in bacterial aggregation as well as anchor point for adhesion in the molecular pathogenesis of Staphylococcus aureus infections

Host blood proteins as bridging ligand in bacterial aggregation as well as anchor point for adhesion in the molecular pathogenesis of Staphylococcus aureus infections
Host blood proteins as bridging ligand in bacterial aggregation as well as anchor point for adhesion in the molecular pathogenesis of Staphylococcus aureus infections

Fibronectin (Fn) and fibrinogen (Fg) are major host proteins present in the extracellular matrix, blood, and coatings on indwelling medical devices. The ability of Staphylococcus aureus to cause infections in humans depends on favorable interactions with these host ligands. Closely related bacterial adhesins, fibronectin-binding proteins A and B (FnBPA, FnBPB) were evaluated for two key steps in pathogenesis: clumping and adhesion. Experiments utilized optical spectrophotometry, flow cytometry, and atomic force microscopy to probe FnBPA/B alone or in combination in seven different strains of S. aureus and Lactococcus lactis, a Gram-positive surrogate that naturally lacks adhesins to mammalian ligands. In the absence of soluble ligands, both FnBPA and FnBPB were capable of interacting with adjacent FnBPs from neighboring bacteria to mediate clumping. In the presence of soluble host ligands, clumping was enhanced particularly under shear stress and with Fn present in the media. FnBPB exhibited greater ability to clump compared to FnBPA. The strength of adhesion was similar for immobilized Fn to FnBPA and FnBPB. These findings suggest that these two distinct but closely related bacterial adhesins, have different functional capabilities to interact with host ligands in different settings (e.g., soluble vs. immobilized). Survival and persistence of S. aureus in a human host may depend on complementary roles of FnBPA and FnBPB as they interact with different conformations of Fn or Fg (compact in solution vs. extended on a surface) present in different physiological spaces.

AFM, adhesion, aggregation, bacteria, clumping, fibronectin-binding proteins
0968-4328
Staats, Amelia M.
67926f6c-53d4-49bb-800c-6e850aaafb0b
Lower, Brian H
b2d95fdd-30ec-4a59-935a-d1f2c3ee2d63
Stoodley, Paul
08614665-92a9-4466-806e-20c6daeb483f
Casillas-Ituarte, Nadia N
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Lower, Steven K
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Staats, Amelia M.
67926f6c-53d4-49bb-800c-6e850aaafb0b
Lower, Brian H
b2d95fdd-30ec-4a59-935a-d1f2c3ee2d63
Stoodley, Paul
08614665-92a9-4466-806e-20c6daeb483f
Casillas-Ituarte, Nadia N
5cdcb4b1-6d70-4d65-aa00-a8466b398c63
Lower, Steven K
b5d6cb17-c0de-4661-9a1a-24d29b12c39b

Staats, Amelia M., Lower, Brian H, Stoodley, Paul, Casillas-Ituarte, Nadia N and Lower, Steven K (2021) Host blood proteins as bridging ligand in bacterial aggregation as well as anchor point for adhesion in the molecular pathogenesis of Staphylococcus aureus infections. Micron, 150, [103137]. (doi:10.1016/j.micron.2021.103137).

Record type: Article

Abstract

Fibronectin (Fn) and fibrinogen (Fg) are major host proteins present in the extracellular matrix, blood, and coatings on indwelling medical devices. The ability of Staphylococcus aureus to cause infections in humans depends on favorable interactions with these host ligands. Closely related bacterial adhesins, fibronectin-binding proteins A and B (FnBPA, FnBPB) were evaluated for two key steps in pathogenesis: clumping and adhesion. Experiments utilized optical spectrophotometry, flow cytometry, and atomic force microscopy to probe FnBPA/B alone or in combination in seven different strains of S. aureus and Lactococcus lactis, a Gram-positive surrogate that naturally lacks adhesins to mammalian ligands. In the absence of soluble ligands, both FnBPA and FnBPB were capable of interacting with adjacent FnBPs from neighboring bacteria to mediate clumping. In the presence of soluble host ligands, clumping was enhanced particularly under shear stress and with Fn present in the media. FnBPB exhibited greater ability to clump compared to FnBPA. The strength of adhesion was similar for immobilized Fn to FnBPA and FnBPB. These findings suggest that these two distinct but closely related bacterial adhesins, have different functional capabilities to interact with host ligands in different settings (e.g., soluble vs. immobilized). Survival and persistence of S. aureus in a human host may depend on complementary roles of FnBPA and FnBPB as they interact with different conformations of Fn or Fg (compact in solution vs. extended on a surface) present in different physiological spaces.

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Accepted/In Press date: 3 August 2021
e-pub ahead of print date: 5 August 2021
Published date: November 2021
Additional Information: Funding Information: This research was funded by National Institutes of Health (NIH) Grant R01HL119648 (SKL) and R01 GM124436-01 (PS). Publisher Copyright: © 2021 The Authors
Keywords: AFM, adhesion, aggregation, bacteria, clumping, fibronectin-binding proteins

Identifiers

Local EPrints ID: 450953
URI: http://eprints.soton.ac.uk/id/eprint/450953
ISSN: 0968-4328
PURE UUID: dcf19e2d-7a73-4862-a3c8-aa448ff894d0
ORCID for Paul Stoodley: ORCID iD orcid.org/0000-0001-6069-273X

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Date deposited: 26 Aug 2021 16:32
Last modified: 17 Mar 2024 06:47

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Contributors

Author: Amelia M. Staats
Author: Brian H Lower
Author: Paul Stoodley ORCID iD
Author: Nadia N Casillas-Ituarte
Author: Steven K Lower

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