Atherosclerosis is the major cause of morbidity and mortality in America. This disease process is defined by the formation of vascular lesions that contain activated macrophages (MO) and dysfunctional endothelial (EC) and smooth muscle cells (SMC). The unfolded protein response (UPR) has been implicated as a cellular process that is induced in atherosclerotic lesions, and in cultured cells (MO, EC and SMC) treated with known pro-atherogenic inducers. The primary aim of this grant will be to explore the function of a novel gene, CHAC1. This protein is specifically induced by UPR activation and is downstream ofthe ATF4-ATF3- CHOP cascade, an important pro-apoptotic pathway ofthe UPR. CHAC1 is a soluble cytosolic peptide, which induces apoptosis when over-expressed, and siRNA knockdown confirms a pro-apoptotic role for this gene. CHAC1 activates TNFRSF6B, a FASL decoy receptor, which functions to antagonize FASL-FAS induced apoptosis signaling. This pathway is of importance because FASL expressing cells can induce apoptosis of MO, EC or SMC, and this my exacerbate the progression of vascular disease. The proposal herein will define the function of CHAC1 at the molecular level, and characterize its contribution to apoptosis and the atherosclerotic disease process in MO, EC and SMC. The contribution of CHAC1 in CHOP and UPR induced apoptosis will be defined using established over-expression plasmids and siRNAs, generation of knockout cells, and assaying different components of putative signaling cascades. Direct binding partners of CHAC1 will also be explored using the TAP method, to define the molecular'^function ofthis gene. Candidates from TAP screening will be validated using co-immuno-precipitation. Based on candidates identified, pijtative functions ofthe chaC domain will be assayed, and targeted deletion and site directed mutagenesis used to define important regions of the protein. Finally, the use of mice that have the CHAC1 gene knocked out will be generated to explore the effects of CHAC1 genetic ablation in the development of atherosclerosis in a mouse disease model.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Transition Award (R00)
Project #
5R00HL094709-04
Application #
8532027
Study Section
Special Emphasis Panel (NSS)
Program Officer
Olive, Michelle
Project Start
2009-09-01
Project End
2015-04-30
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
4
Fiscal Year
2013
Total Cost
$235,444
Indirect Cost
$71,941
Name
Louisiana State Univ Hsc New Orleans
Department
Pharmacology
Type
Schools of Medicine
DUNS #
782627814
City
New Orleans
State
LA
Country
United States
Zip Code
70112