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.
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.
People |
ORCID iD |
Ian Sabroe (Principal Investigator / Fellow) |
Publications

Prince LR
(2008)
Subversion of a lysosomal pathway regulating neutrophil apoptosis by a major bacterial toxin, pyocyanin.
in Journal of immunology (Baltimore, Md. : 1950)


Sabroe I
(2007)
Targeting the networks that underpin contiguous immunity in asthma and chronic obstructive pulmonary disease.
in American journal of respiratory and critical care medicine

Ward JR
(2010)
Temporal interleukin-1beta secretion from primary human peripheral blood monocytes by P2X7-independent and P2X7-dependent mechanisms.
in The Journal of biological chemistry

Parker LC
(2009)
The generation of highly purified primary human neutrophils and assessment of apoptosis in response to Toll-like receptor ligands.
in Methods in molecular biology (Clifton, N.J.)

Anwar S
(2009)
The rise and rise of Staphylococcus aureus: laughing in the face of granulocytes.
in Clinical and experimental immunology

Sabroe I
(2008)
The role of TLR activation in inflammation.
in The Journal of pathology

Medvedev AE
(2006)
Tolerance to microbial TLR ligands: molecular mechanisms and relevance to disease.
in Journal of endotoxin research

Sabroe I
(2007)
Toll-like receptor (TLR)-based networks regulate neutrophilic inflammation in respiratory disease.
in Biochemical Society transactions

Ward JR
(2009)
Translational mini-review series on immunology of vascular disease: inflammation, infections and Toll-like receptors in cardiovascular disease.
in Clinical and experimental immunology

Parker LC
(2007)
Translational mini-review series on Toll-like receptors: networks regulated by Toll-like receptors mediate innate and adaptive immunity.
in Clinical and experimental immunology
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 | 07/2008 |
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 | 09/2009 |
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 | 09/2009 |
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 |