Information Services banner Edinburgh Research Archive The University of Edinburgh crest

Edinburgh Research Archive >
Clinical Sciences, School of >
School of Clinical Sciences thesis and dissertation collection >

Please use this identifier to cite or link to this item:

This item has been viewed 53 times in the last year. View Statistics

Files in This Item:

File Description SizeFormat
Li2011.doc29.54 MBMicrosoft Word
Li2011.pdf8.92 MBAdobe PDFView/Open
Title: Impact of cationic host defence peptide LL-37 on human neutrophil death and inflammatory responses
Authors: Li, Hsin-Ni
Supervisor(s): Davidson, Donald
Rossi, Adriano
Barlow, Paul
Issue Date: 5-Jul-2011
Publisher: The University of Edinburgh
Abstract: Cathelicidins are cationic host defence peptides (CHDP) with essential roles in the innate defence system. These peptides have antimicrobial potential and the capacity to modulate innate immunity and inflammatory processes. Neutrophils (PMN) are the main reservoir of cathelicidins and play key roles in first line defence against infection. The appropriate regulation of PMN function, death, and clearance is critical to innate immunity, and the efferocytosis of apoptotic PMN, in contrast to necrotic cells, is proposed to promote the resolution of inflammation. In this thesis I demonstrate that the human cathelicidin LL-37 rapidly induced secondary necrosis of apoptotic human PMN and identify the essential C-terminal region of LL-37 required for this activity. In addition to the induction of secondary necrosis, higher concentrations of LL-37 also promoted PMN granule contents release. LL-37-induced secondary necrosis did not affect PMN ingestion by human monocyte-derived macrophages and, in contrast to expectation, was not proinflammatory. Interestingly, the anti-inflammatory effects of apoptotic PMN on activated macrophages were retained and even potentiated where LL-37-mediated secondary necrosis induced anti-inflammatory granule content release. Consistent with the results of in vitro studies, in vivo murine sterile peritonitis model revealed the same phenomenon: LL-37-induced secondary necrosis diminished inflammatory responses with decreased PMN influx. I also present data on LL-37- mediated modulation of innate immune effector cell cytokines responses to inflammatory signals. I propose that during acute inflammation LL-37 can modulate innate immune responses through its activity on cytokine production, and that LL-37-mediated secondary necrosis of apoptotic PMN has anti-inflammatory effects, but may also mediate host damage by promoting the release of potentially harmful intracellular contents under chronic or dysregulated conditions.
Sponsor(s): University of Edinburgh
Keywords: Cathelicidins
cationic host defence peptides
cell cytokines
Appears in Collections:School of Clinical Sciences thesis and dissertation collection

Items in ERA are protected by copyright, with all rights reserved, unless otherwise indicated.


Valid XHTML 1.0! Unless explicitly stated otherwise, all material is copyright © The University of Edinburgh 2013, and/or the original authors. Privacy and Cookies Policy