Page 1 |
Save page Remove page | Previous | 1 of 184 | Next |
|
small (250x250 max)
medium (500x500 max)
large ( > 500x500)
Full Resolution
All (PDF)
|
This page
All
Subset |
LDL PROTEIN NITRATION: IMPLICATION FOR PROTEIN UNFOLDING AND
MITOCHONDRIAL FUNCTION BY P-JNK-2
by
Ryan Thomas Littleton Hamilton
_____________________________________________________________________
A Dissertation Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
DOCTOR OF PHILOSOPHY
(MOLECULAR PHARMACOLOGY AND TOXICOLOGY)
December 2007
Copyright 2007 Ryan Thomas Littleton Hamilton
Object Description
| Title | LDL protein nitration: implication for protein unfolding and mitochondrial function by p-JNK-2 |
| Author | Hamilton, Ryan Thomas Littleton |
| Author email | rhamilto@usc.edu |
| Degree | Doctor of Philosophy |
| Document type | Dissertation |
| Degree program | Molecular Pharmacology & Toxicology |
| School | School of Pharmacy |
| Date defended/completed | 2007-10-22 |
| Date submitted | 2007 |
| Restricted until | Unrestricted |
| Date published | 2007-11-16 |
| Advisor (committee chair) | Cadenas, Enrique |
| Advisor (committee member) |
Brinton, Roberta Hodis, Howard |
| Abstract | An elevated level of LDL cholesterol is associated with the development of atherosclerosis and is also associated with aging. Modification of LDL particle is one of the main contributors to the development of atherosclerosis and is elevated with increasing plasma LDL concentrations. Modified LDL is usually composed of LOOH/aldehydes, unfolded protein and some protein post-translational modifications. It has been debated whether the lipid peroxides or unfolded apoB-100 protein is important. An important pathway in atherosclerosis may be the phosphorylation of JNK-2 in ECs. OxLDL-R CD-36 knockout macrophages which have decreased foam cell formation and decreased JNK-2 phosphorylation as well as an ApoE and JNK-2 double knockout mouse has decreased lesion size and MFC formation. Foam cells have increased ROS production and mitochondria are the major source of ROS and this evidence may suggest that p-JNK-2 is involved in regulating mitochondrial function.; We hypothesize that ONOO- induced nitration and unfolding of apoB-100 may be a potential mechanism for modification of LDL in vivo and that this unfolded LDL induces oxLDL-R dependent irreversible mitochondrial dysfunction in ECs to promote atherosclerosis. The purpose of this study was to determine (a) where the modified fraction of LDL in vivo (LDL-) is nitrated, (b) whether ONOO- produces a particle with a similar nitration pattern and protein unfolding to in vivo LDL-, (c) whether nitrotyrosine is co-localized to the bifurcation and whether OSS induces ONOO- formation, (d) how differentially modified LDL induces JNK-2 phosphorylation, (e) what oxLDL receptors are involved in the phosphorylation of JNK-2, (f) whether phospho-JNK-2 co-localizes with mitochondria and is regulating mitochondrial function. The modified LDL fraction in vivo (LDL-) is nitrated in alpha helices that are involved in protein unfolding. It was also determined that ONOO- treated LDL had a similar nitration and unfolding to in vivo LDL-.; We found that human coronary artery at the bifurcation where atherosclerosis is prevalent and OF occurs were positive for nitrotyrosine and implicated ONOO- formation by a 1:1 ratio of O2.- and .NO production. Protein unfolding of LDL was the most important initiator of JNK-2 phosphorylation. Upon receptor blocking, JNK-2 phosphorylation was dependent on both CD-36 and SR-A oxLDL-R. Modified LDL dependent JNK-2 phosphorylation co-localized with mitochondria and was ablated by both SR-A and CD-36 receptor blocking antibodies but was only minimally affected by either one alone suggesting that both receptors are induce p-JNK-2 co-localization tomitochondria. Phosphorylation of Bcl-xL and caspase-3 activation was blocked by incubation with both CD-36 and SR-A receptor blocking antibodies. Human coronary arteries in diseased hearts were robustly positive for CD-36 and p-JNK-2 colocalization with mitochondria in ECs of the lumen and of the vasa vasorum as well as in macrophages, MFCs and SMCs. Our findings demonstrate that ONOO- may be involved in the modification of LDL in vivo, that ONOO- modified LDL was similar in structure and nitration pattern to an in vivo nitrated LDL particle and that proteinunfolding is involved in the initiation of apoptosis and atherosclerosis through an oxLDL-R dependent phosphorylation of JNK-2. |
| Keyword | LDL; nitration; JNK-2; endothelial cell dysfunction; mitochondrial dysfunction; apoptosis |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Type | texts |
| Legacy record ID | usctheses-m927 |
| Rights | Hamilton, Ryan Thomas Littleton |
| Repository name | Libraries, University of Southern California |
| Repository address | Los Angeles, California |
| Repository email | http://www.usc.edu/isd/libraries/services/ask_a_librarian/email/ |
| Filename | etd-Hamilton-20071116 |
| Archival file | uscthesesreloadpub_Volume62/etd-Hamilton-20071116.pdf |
Description
| Title | Page 1 |
| Full text | LDL PROTEIN NITRATION: IMPLICATION FOR PROTEIN UNFOLDING AND MITOCHONDRIAL FUNCTION BY P-JNK-2 by Ryan Thomas Littleton Hamilton _____________________________________________________________________ A Dissertation Presented to the FACULTY OF THE GRADUATE SCHOOL UNIVERSITY OF SOUTHERN CALIFORNIA In Partial Fulfillment of the Requirements for the Degree DOCTOR OF PHILOSOPHY (MOLECULAR PHARMACOLOGY AND TOXICOLOGY) December 2007 Copyright 2007 Ryan Thomas Littleton Hamilton |
Comments
Post a Comment for Page 1
