Strategies to attenuate microvascular endothelial cell hyperpermeability : a dissertation /
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| Format: | Thesis Book |
| Language: | English |
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[College Station, Tex.] :
[Texas A&M University System Health Science Center],
[2012]
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| Subjects: |
| Abstract: | ABSTRACT: Microvascular hyperpermeability is frequently observed in patients with traumatic injury induced hemorrhagic shock and this microcirculatory abnormality correlates to worse clinical complication. In this dissertation, I have attempted to demonstrate various strategies to attenuate microvascular endothelial cell hyperpermeability by studying adherens junctional complex proteins, VE-cadherin and [beta]-catenin and illustrating cellular and molecular mechanisms involved in extrinsic apoptotic signaling molecules such as TNF-[alpha] and Fas ligand. The results from this dissertation demonstrated that post-translational VE-cadherin gene silencing in vitro and recombinant mutant VE-cadherin transfection in vivo and in vitro showed increase in permeability in endothelial cells. The inhibition of VE-cadherin proteasomal degradation pathway using proteasomal inhibitor, MG-132 preserved endothelial cell adherens junction barrier integrity. Recombinant [beta]-catenin protein and [beta]-catenin gene transfection prevented the pro-apoptotic molecule, BAK induced endothelial cell hyperpermeability. Inhibition of [beta]-catenin phosphorylation through GSK-3[beta] specific inhibitor, SB126763 demonstrated an increase in [beta]-catenin mediated TCF transcriptional activity and attenuated BAK induced endothelial cell hyperpermeability. TNF-[alpha] induced increase in endothelial cell permeability demonstrated involvement of mitochondria mediated intrinsic apoptotic signaling pathway. TNF-[alpha] treatment showed increase in mitochondrial reactive oxygen species formation and decrease in mitochondrial transmembrane potential in the endothelial cells. Recombinant Bcl-xL protein treatment showed protection against TNF-[alpha] induced increase in caspase-3 activity and endothelial cell barrier dysfunction. The increase in caspase-3 activity did not correspond to increase in cell death during endothelial cell hyperpermeability. Fas ligand blocker, FasFc showed protection against hemorrhagic shock serum induced drop in mitochondrial transmembrane potential, disruption of the adherens junctions, increase in actin stress fiber formation and endothelial cell hyperpermeability. In conclusion, microvascular endothelial cell hyperpermeability can be attenuated by stabilizing or strengthening the adherens junctional protein complex through preventing the proteasome degradation of VE-cadherin or increasing the intracellular levels of [beta]-catenin. Furthermore, endothelial cell barrier integrity can be preserved by protecting mitochondrial physiology from apoptotic signal at the receptor level using FasFc. The findings from this dissertation have therapeutic potential to become effective targets in the fight against microvascular hyperpermeability. |
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| Item Description: | Vita. "Major Subject: Medical Sciences". "Submitted to the Office of Research and Graduate Studies of the Texas A&M University System Health Science Center in partial fulfillment of the requirements for the degree of Doctor of Philosophy August 18 2012." Approved as to style and content by: edition W. Childs, Martha Karen Newell Rogers, Travis W. Hein, Binu Tharakan, William Roy Smythe. |
| Physical Description: | xiv, 174 leaves : illustrations ; 28 cm. |
| Bibliography: | Includes bibliographical references. |