The control of Toll-like receptor (TLR)-mediated neutrophil activation

Lead Research Organisation: University of Sheffield
Department Name: Medicine and Biomedical Science

Abstract

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Technical Summary

A white blood cell, the neutrophil, is a principal defence against infection. Its recruitment to, and activation within, tissues results in the removal of microbes and survival of the host. Unfortunately, inappropriate neutrophil activation also occurs in many lung diseases, contributing to tissue damage, and ultimately ill health or even death. This project will develop a deeper understanding of the ways in which neutrophils are activated by microbial products, which are sensed by the neutrophil using proteins called Toll-like receptors (TLRs).
We propose that neutrophils recruited into tissue will show altered patterns of TLR responses, which will affect their tissue positioning and activation. Our first set of studies will determine patterns of neutrophil responses in tissue cells compared with those in the peripheral blood, using a range of established and novel assays of neutrophil activation. We will subsequently investigate the molecular mechanisms underpinning altered cell phenotype at the level of intracellular signalling. We will determine how TLR signalling affects subsequent cell migration and activation driven by other neutrophil activators, principally chemoattractants.
We hypothesise that neutrophil responses to TLR agonists will be determined by trafficking of the TLR to the cell membrane and specific intracellular compartments, and will explore this in primary neutrophils in collaboration with Prof Smythe (Sheffield University). We will determine if activated TLRs can recycle to the cell membrane, and if control of recycling provides further mechanisms to regulate neutrophil responses. In parallel, we will determine the molecular pathways resulting in TLR internalisation and reexpression in cell lines. We propose that the box 3 region of the intracellular TIR domain may be involved in trafficking of receptors, and we will use strategies involving receptor mutagenesis and construction of chimaeric proteins to determine the importance of these regions in receptor function.
Finally, we hypothesise that neutrophils become rapidly unresponsive to TLR agonists, which we propose is part of a mechanism preventing their excessive activation at inflammatory sites. We have developed novel preliminary data describing the cellular and molecular mechanisms causing neutrophils to become unresponsive, and will study these systems in more detail to determine if they represent therapeutic targets controlling neutrophil activation. We will investigate whether other inflammatory products also serve to limit neutrophil inflammation by inhibiting TLR activation in these cells.
These studies will identify new ways of targeting neutrophilic activation in inflammatory disease with wide-ranging therapeutic consequences for respiratory diseases including asthma and COPD.

Publications

10 25 50
 
Description Asthma UK Project Grant
Amount £141,000 (GBP)
Organisation Asthma UK 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2008 
End 01/2011
 
Description Asthma UK/MRC Capacity-building studentship
Amount £60,000 (GBP)
Organisation Asthma UK 
Sector Charity/Non Profit
Country United Kingdom
Start 08/2008 
End 07/2011
 
Description BHF Project Grant
Amount £130,000 (GBP)
Organisation British Heart Foundation (BHF) 
Sector Charity/Non Profit
Country United Kingdom
Start 01/2006 
End 12/2008
 
Description MRC Project Grant
Amount £712,000 (GBP)
Organisation Medical Research Council (MRC) 
Sector Public
Country United Kingdom
Start 10/2009 
End 09/2012
 
Description Sheffield Hospitals Charitable Trust, Project Grant
Amount £50,000 (GBP)
Organisation Sheffield Hospitals Charity 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2009 
End 09/2010
 
Description Wellcome Trust Project Grant (Inhibiting TLR signalling by disruption of membrane microdomains)
Amount £281,482 (GBP)
Funding ID 091498 
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2011 
End 01/2014
 
Description Analysis of novel TLR antagonist 
Organisation Allergy Therapeutics
Country United Kingdom 
Sector Private 
PI Contribution Collaboration resulting in description of new reagent as a novel TLR antagonist. Likely to be taken further in the future.
Collaborator Contribution Collaboration resulting in description of new reagent as a novel TLR antagonist. Likely to be taken further in the future.
Impact Collaboration resulting in description of new reagent as a novel TLR antagonist. Likely to be taken further in the future.
Start Year 2006
 
Description National Science Week School visit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? Yes
Primary Audience Schools
Results and Impact Approx 120 students aged 14-16 attended a talk on airways inflammation and asthma, given by me and my group (including LCP who was funded by this fellowship).

Generated interest by school children in asthma and inflammation
Year(s) Of Engagement Activity 2010
 
Description Talks at International Meeting 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Primary Audience Health professionals
Results and Impact 'Targeting TLRs'. New Drugs for Asthma and COPD, Brompton Hospital 2008. 'The networks that regulate innate and adaptive immunity in asthma and COPD'. Invited talk for the joint BTS/BALR symposium at the British Thoracic Society Winter meeting, London 2007. 8th Annual Lund COPD Symposium April 2007 talk title 'Integration of the innate and adaptive immune responses in COPD'. Chair of Session and speaker at British Society for Allergy and Clinical Immunology, July 2007. Talk title 'Inflammatory Networks of Asthma' 'Toll-like receptors:  Potential therapeutic aspects'. Joint British Thoracic Society/ British Society for Allergy and Clinical Immunology, BTS Winter meeting, Dec 2006

Generated useful collaborations and raised importance of field
Year(s) Of Engagement Activity 2006,2007,2008