Suresh, Sangita
(2009)
FUNCTIONAL CHARACTERIZATION OF APOLIPOPROTEIN H POLYMORPHISMS AND THEIR RELATION TO SYSTEMIC LUPUS ERYTHEMATOSUS.
Doctoral Dissertation, University of Pittsburgh.
(Unpublished)
Abstract
Sequence variation in gene promoters is often associated with disease risk. In this study, a 1,418 bp sequence of the 5'-flanking region of the APOH (encoding for β₂-glycoprotein I) has been functionally characterized by in vitro analysis. Associations of APOH promoter SNPs with systemic lupus erythematosus (SLE) risk and related phenotypes along with their effect on human plasma β₂GPI levels were examined. Transient transfections, dual-luciferase reporter gene assays were performed in COS-1 and HepG2 cells. HepG2 nuclear extracts was used for electrophoretic mobility shift assay (EMSA). A case-control design and genotyped 345 SLE women and 454 healthy control women for 12 APOH promoter single nucleotide polymorphisms (SNPs) (-1284C>G, -1219G>A, -1190G>C, -1076G>A, -1055T>G, -759A>G, - 700C>A, -643T>C, -627A>C, -581A>C, -363C>T -38G>A, and -32C>A). Haplotype analyses were performed using EH (Estimate Haplotype-frequencies) and Haploview programs. Deletion analysis localized the core promoter of APOH ∼160 bp upstream of ATG codon with the presence of critical cis-acting elements between -166 and -65. Functional relevance for three SNPs (-1219G>A, -643T>C and -32C>A) that resulted in lower promoter activity (51%, 40% and 37%, respectively) as compared to the wild-type alleles in COS-1 cells. EMSA demonstrated HepG2 nuclear protein(s) bind to the elements located in the regions of the three SNPs. Overall haplotype distribution of the APOH promoter SNPs was significantly different between cases and controls (P = 0.009). The -643C allele was found to be protective against carotid plaque formation (adjusted OR = 0.37, P = 0.013) among SLE patients. Three-site haplotype analysis revealed one haplotype carrying -32A to be significantly associated with decreased plasma β₂GPI levels (P < 0.001) and another haplotype harboring the minor allele for -1219A showed a significant albeit less pronounced association (P = 0.046). Our data indicate that APOH promoter variants may be involved in the etiology of SLE, especially the risk for autoimmune-mediated cardiovascular disease. Public Health Significance: Cardiovascular disease is the leading cause of death in the U.S. and other developed nations. Understanding its pathogenesis will help in formulating newer therapeutic strategies and treatment that may decrease the adverse consequences of accelerated atherosclerosis in SLE patients.
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| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
29 January 2009 |
| Date Type: |
Completion |
| Defense Date: |
24 November 2008 |
| Approval Date: |
29 January 2009 |
| Submission Date: |
3 December 2008 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
School of Public Health > Human Genetics |
| Degree: |
PhD - Doctor of Philosophy |
| Thesis Type: |
Doctoral Dissertation |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
β₂-GLYCOPROTEIN I; APOLIPOPROTEIN H; POLYMORPHISM; PROMOTER; SYSTEMIC LUPUS ERYTHEMATOSUS |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-12032008-175014/, etd-12032008-175014 |
| Date Deposited: |
10 Nov 2011 20:07 |
| Last Modified: |
15 Nov 2016 13:52 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/9999 |
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