The identification of novel susceptibility genes for complex diseases like COPD could transform our understanding of disease pathophysiology and provide new pathways for treatment. We have recently collaborated in case-control genome-wide association studies that have provided compelling evidence for association of COPD susceptibility with regions on chromosome 15 (near IREB2), chromosome 4 (near HHIP), and another region on chromosome 4 (in FAM13A). However, the key genes within these GWAS loci have not been absolutely verified, and the key functional variants within these GWAS loci have not been identified. We will address several key hypotheses that will assist in the localization of functional genetic determinants within GWAS loci and investigation of their biological mechanisms: 1) African Americans and non-Hispanic Whites will share a subset of COPD genetic determinants;assessing the overlap of genetic association between these groups will localize COPD susceptibility genes;2) Many of the functional variants influencing COPD susceptibility will regulate gene expression;and 3) Studies of Fami3a, Hhip, and /reib2 knockout mice exposed to cigarette smoke will identify the activities of these genes in COPD pathogenesis. In order to address these hypotheses and to identify potentially functional variants influencing COPD susceptibility, we will begin by localizing functional variants for COPD susceptibility in three existing GWAS loci (HHIP, FAM13A, and IREB2) using association analysis of dense SNP panels in African-American subjects from COPDGene to narrow shared COPD susceptibility regions between African-American and non-Hispanic White subjects. To localize key variants, we will assess regulatory regions around genes in these GWAS loci using chromosome conformation capture and chromatin immunoprecipitation assays. We will also assess the impact of specific variants in the regulatory region in luciferase reporter assays. We will use shRNA-mediated silencing of genes in the GWAS loci to assess whether these genes regulate the function of lung epithelial and monocyte cells lines and validate these results in primary cells. Finally, the impact of three key regional genes in GWAS loci on COPD pathogenesis will be assessed in knockout mice exposed to cigarette smoke. This project will identify the key COPD genes within GWAS loci and demonstrate the functional impact of those genes on COPD susceptibility. The multidisciplinary investigations of genetic association, genomic interactions, in vitro cell-based assays, and cigarette smokeexpose knockout mice in this project will provide important and novel insights into COPD pathogenesis.

Public Health Relevance

Recent genetic studies have found areas of the human genome that influence the risk of developing chronic obstructive pulmonary disease (COPD) in cigarette smokers. This project will find the specific genes in these areas and begin to determine why these genes are responsible for COPD risk. This study will improve our understanding of COPD, and it is an important first step towards developing new treatments for COPD.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Program Projects (P01)
Project #
5P01HL105339-04
Application #
8685305
Study Section
Heart, Lung, and Blood Initial Review Group (HLBP)
Project Start
Project End
Budget Start
2014-07-01
Budget End
2015-06-30
Support Year
4
Fiscal Year
2014
Total Cost
$558,383
Indirect Cost
$117,773
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
02115
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Wang, Longfei; Lee, Sungyoung; Gim, Jungsoo et al. (2016) Family-Based Rare Variant Association Analysis: A Fast and Efficient Method of Multivariate Phenotype Association Analysis. Genet Epidemiol 40:502-11

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