dc.contributor.author | Beal, Robert William John | |
dc.date.accessioned | 2018-09-18T15:30:31Z | |
dc.date.available | 2018-09-18T15:30:31Z | |
dc.date.issued | 2018-09-03 | |
dc.date.submitted | 2018-09-18T13:39:20.393Z | |
dc.identifier.citation | Beal, R.W.J. 2018. Investigating the role of Junctional Adhesion Molecule-C (JAM-C) in endothelial cell biology in vitro and in vivo using human and mouse models. Queen Mary University of London | en_US |
dc.identifier.uri | http://qmro.qmul.ac.uk/xmlui/handle/123456789/44687 | |
dc.description | PhD | en_US |
dc.description.abstract | Junctional adhesion molecule C (JAM-C) is a component of endothelial cell (EC) tight junctions that has been implicated in a number of endothelial functions, such as angiogenesis and trafficking of leukocytes through the endothelium during inflammation. Work within our lab has identified that loss of JAM-C at EC junctions results in increased reverse transendothelial migration (rTEM) of neutrophils back into the circulation, a response that has been associated with the dissemination of inflammation to distant organs. Whilst the mechanism by which JAM-C is lost or redistributed away from EC junctions has begun to be elucidated, little is known about how loss of endothelial JAM-C impacts the functions of ECs. As such, this thesis aimed to investigate the effect of JAM-C deficiency on EC functions to unravel possible molecular and cellular mechanisms of mediating neutrophil rTEM.
To address the effect of JAM-C deficiency on EC functions, an in vitro RNA interference (RNAi) approach was used to efficiently knock-down (KD) JAM-C in human umbilical vein ECs (HUVECs). Importantly, KD of JAM-C did not affect expression of other key EC junctional markers such as JAM-A and VE-Cadherin and cell proliferation and apoptosis were similarly unaffected. Gene expression profiling using microarrays revealed that JAM-C depleted HUVECs exhibited a pro-inflammatory phenotype under basal conditions that was characterised by increased expression of pro-inflammatory genes such as ICAM1 and IL8.
Following IL-1β-induced inflammation, no difference in expression of pro-inflammatory genes was detected between control and JAM-C KD HUVECs. However, protein levels of secreted chemokines such as IL-8 were reduced in JAM-C KD HUVECs following stimulation with IL-1β. This was corroborated by in vivo studies demonstrating reduced levels of secreted chemokines in the plasma of mice where JAM-C was conditionally deleted from ECs.
A novel finding of this work is the demonstration that JAM-C KD HUVECs exhibit increased autophagy under basal conditions. This might provide a potential mechanism for the reduced chemokine secretion that is observed in this system,
whereby chemokines are preferentially trafficked for autophagosome-mediated degradation.
Taken together, these findings indicate a multi-functional role for JAM-C in regulating EC homeostasis under basal conditions. JAM-C KD ECs respond aberrantly to inflammatory stimuli by secreting reduced chemokine levels, a consequence that could provide novel insights into the mechanisms of neutrophil rTEM under conditions of endothelial JAM-C loss. | en_US |
dc.description.sponsorship | Wellcome Trust | en_US |
dc.language.iso | en | en_US |
dc.publisher | Queen Mary University of London | en_US |
dc.rights | The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author | |
dc.subject | Microvascular Research | en_US |
dc.subject | Junctional Adhesion Molecule-C | en_US |
dc.subject | endothelial cell biology | en_US |
dc.title | Investigating the role of Junctional Adhesion Molecule-C (JAM-C) in endothelial cell biology in vitro and in vivo using human and mouse models | en_US |
dc.type | Thesis | en_US |