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dc.contributor.advisorDavidson, Donald
dc.contributor.advisorRossi, Adriano
dc.contributor.advisorBarlow, Paul
dc.contributor.authorLi, Hsin-Ni
dc.date.accessioned2011-11-01T10:47:57Z
dc.date.available2011-11-01T10:47:57Z
dc.date.issued2011-07-05
dc.identifier.urihttp://hdl.handle.net/1842/5597
dc.description.abstractCathelicidins 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.en
dc.contributor.sponsorUniversity of Edinburghen
dc.language.isoenen
dc.publisherThe University of Edinburghen
dc.relation.hasversionBjorstad, A., Askarieh, G., Brown, K.L., Christenson, K., Forsman, H., Onnheim, K., Li, H.N., Teneberg, S., Maier, O., Hoekstra, D., Dahlgren, C., Davidson, D.J., Bylund, J. (2009) The host defense peptide LL-37 selectively permeabilizes apoptotic leukocytes. Antimicrob Agents Chemother 53, 1027-38.en
dc.relation.hasversionSemple F, Webb S, Li HN, Patel HB, Perretti M, Jackson IJ, Gray M, Davidson DJ, and Dorin JR (2010) Human beta-defensin 3 has immunosuppressive activity in vitro and in vivo. Eur. J. Immunol. 40(4): 1073-8en
dc.relation.hasversionLi HN, Barlow PG, Bylund J, Mackellar A, Björstad A, Conlon J, Hiemstra PS, Haslett C, Gray M, Simpson AJ, Rossi AG, and Davidson DJ (2009) Secondary necrosis of apoptotic neutrophils induced by the human cathelicidin LL-37 is not proinflammatory to phagocytosing macrophages. J. Leuk. Biol. 86(4): 891-902en
dc.subjectCathelicidinsen
dc.subjectcationic host defence peptidesen
dc.subjectCHDPen
dc.subjectNeutrophilsen
dc.subjectPMNen
dc.subjectanti-inflammatoryen
dc.subjectmacrophagesen
dc.subjectcell cytokinesen
dc.titleImpact of cationic host defence peptide LL-37 on human neutrophil death and inflammatory responsesen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelDoctoralen
dc.type.qualificationnamePhD Doctor of Philosophyen


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