Publications by authors named "Phillipa C White"

2 Publications

  • Page 1 of 1

Modulation of Neutrophil Extracellular Trap and Reactive Oxygen Species Release by Periodontal Bacteria.

Infect Immun 2017 12 17;85(12). Epub 2017 Nov 17.

Periodontal Research Group, Birmingham Dental School and Hospital, Institute of Clinical Sciences, The University of Birmingham and Birmingham Community Health NHS Trust, Edgbaston, Birmingham, United Kingdom

Oral bacteria are the main trigger for the development of periodontitis, and some species are known to modulate neutrophil function. This study aimed to explore the release of neutrophil extracellular traps (NETs), associated antimicrobial proteins, and reactive oxygen species (ROS) in response to periodontal bacteria, as well as the underlying pathways. Isolated peripheral blood neutrophils were stimulated with 19 periodontal bacteria. NET and ROS release, as well as the expression of NET-bound antimicrobial proteins, elastase, myeloperoxidase, and cathepsin G, in response to these species was measured using fluorescence-based assays. NET and ROS release was monitored after the addition of NADP (NADPH) oxidase pathway modulators and inhibitors of Toll-like receptors (TLRs). Moreover, bacterial entrapment by NETs was visualized microscopically, and bacterial killing was assessed by bacterial culture. Certain microorganisms, e.g., and , stimulated higher levels of ROS and NET release than others. NETs were found to entrap, but not kill, all periodontal bacteria tested. NADPH oxidase pathway modulators decreased ROS production but not NET production in response to the bacteria. Interestingly, TLR inhibitors did not impact ROS and NET release. These data suggest that the variability in the neutrophil response toward different bacteria may contribute to the pathogenesis of periodontal diseases by mechanisms such as bacterial avoidance of host responses and activation of neutrophils. Moreover, our results indicate that bacterium-stimulated NET release may arise in part via NADPH oxidase-independent mechanisms. The role of TLR signaling in bacterium-induced ROS and NET release needs to be further elucidated.
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http://dx.doi.org/10.1128/IAI.00297-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5695129PMC
December 2017

Characterization, Quantification, and Visualization of Neutrophil Extracellular Traps.

Methods Mol Biol 2017 ;1537:481-497

Institute of Clinical Sciences, College of Medical and Dental Sciences, The School of Dentistry, University of Birmingham, 5 Mill Pool Way, Edgbaston, Birmingham, B5 7EG, UK.

Following the discovery of neutrophil extracellular traps (NETs) in 2004 by Brinkmann and colleagues, there has been extensive research into the role of NETs in a number of inflammatory diseases, including periodontitis. This chapter describes the current methods for the isolation of peripheral blood neutrophils for subsequent NET experiments, including approaches to quantify and visualize NET production, the ability of NETs to entrap and kill bacteria, and the removal of NETs by nuclease-containing plasma.
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http://dx.doi.org/10.1007/978-1-4939-6685-1_29DOI Listing
January 2018