Vascular endothelial cells (VECs) maintain vascular integrity by regulating the passage of solutes, macromolecules, and cells between the vascular and perivascular space and are critical in a wide number of physiological processes, such as the delivery of nutrients and oxygen to surrounding tissues, leukocyte trafficking, angiogenesis, and tissue repair. VEC permeability is regulated, at least in part, by VE-cadherin-based adherens junctions that coordinate inter-VEC contacts and communicate the strength of these interactions to the cell via the actin cytoskeleton. Although the ubiquitous second messenger, cyclic adenosine 3', 5'-monophosphate (cAMP), has been shown to reduce VEC permeability, the molecular basis of this effect is currently unclear. Herein, we report that cAMP and its two effectors, cAMP-dependent protein kinase A-II (PKA-II) and exchange protein activated by cAMP-1 (EPAC1), improve barrier function and differentially coordinate this effect through both VE-cadherin and actin cytoskeletal structures. We have also identified cyclic nucleotide phosphodiesterase (PDE) 4 as the major PDE regulating VEC barrier function. Through the use of cAMP-elevating agents and RNAi-mediated knockdown of PKA-Cα, EPAC1 and PDE4D, we have identified a dominant role for EPAC1 in VEC permeability as well as recognized PDE4D as a potential adaptor protein VE-cadherin-based complexes. Our results are consistent with previous reports of a role for both PKA and EPAC1 in controlling VE-cadherin mediated barrier function and additionally provide novel insight into the differential roles that PKA, EPAC1 and PDE4D play in stabilizing VEC barrier function. / Thesis (Master, Pathology & Molecular Medicine) -- Queen's University, 2009-09-18 16:09:59.12
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OKQ.1974/5173 |
| Date | 22 September 2009 |
| Creators | Rampersad, Sarah |
| Contributors | Queen's University (Kingston, Ont.). Theses (Queen's University (Kingston, Ont.)) |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Format | 5410429 bytes, application/pdf |
| Rights | This publication is made available by the authority of the copyright owner solely for the purpose of private study and research and may not be copied or reproduced except as permitted by the copyright laws without written authority from the copyright owner. |
| Relation | Canadian theses |
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