Systemic lupus erythematosus (SLE or lupus) is a debilitating autoimmune disease with substantial heritability. It is characterized by a broad spectrum of clinical manifestations including pathogenic autoantibody production and multi-system organ damage. Compared to European-Americans (EA), Asians have at least 3-fold higher prevalence of SLE and more severe clinical manifestations, including life-threatening kidney damage. Genetic variation between ethnicities could account for underlying differences in disease severity and clinical manifestations. Development of new and more effective approaches for prevention and treatment requires improved understanding of disease mechanisms. While recent genome-wide association studies (GWAS) have identified over 40 genes/loci, differentiating between pathological and benign DNA changes is a major challenge. Lack of understanding causal effects underlying GWAS signals has hindered development of SLE diagnostics and treatments. GWAS results indicate that the genetic architecture of SLE in Asians may differ from more extensively studied European-derived populations. Thus, it is necessary to identify primary causal variants that influence SLE development in Asian populations. Our research team has the experience, expertise, resources and infrastructure necessary to move beyond GWAS to accelerate the discovery of causal variants underlying these signals and their functional effects. We have successfully identified SLE predisposing variants from IFIH1, ITGAM, and NCF2 loci, and experimentally defined mechanisms influencing SLE risk. Based on our preliminary data from >11,000 Koreans and Chinese, we propose to study 6 highly significant (10-99 Aim 1 is to pinpoint functional variants within 6 candidate genes in Asian populations by performing deep sequencing followed by imputation-based association analysis. We will also define the relationship between these variants and SLE clinical sub-phenotypes and autoantibody profiles. Significant SNPs, especially rare variants, will be validated with follow-up genotyping.
Aim 2 is to predict and validate mechanistic effects of SLE-predisposing variants. We will employ bioinformatic analysis and molecular modeling to prioritize associated variants and select putative SNPs for appropriate experimental validation by adapting our established pipeline for functional assays. We will also identify networks involving our target predisposing SNPs, and genes affecting pathways that could influence SLE pathogenesis. Finally, we will experimentally validate functional effects of variants to define disease mechanisms. These results will provide new insights into mechanisms by which these variants contribute to lupus, and accelerate identification and validation of novel targets as well as development of treatments and future therapeutic interventions for lupus.

Public Health Relevance

Lupus is a chronic inflammatory autoimmune disease with profound associated mortality and morbidity that disproportionally affects women and ethnic populations. Lupus has a substantial genetic component, and this project will focus on 6 genes that potentially contribute to this disease. We will identify SLE causal variants for these genes and mechanistically validate their contributions to pathogenesis, potentially offering options for future therapeutic interventions for lupus.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR060366-09
Application #
9746582
Study Section
Genetics of Health and Disease Study Section (GHD)
Program Officer
Wang, Yan Z
Project Start
2010-09-20
Project End
2021-06-30
Budget Start
2019-07-01
Budget End
2021-06-30
Support Year
9
Fiscal Year
2019
Total Cost
Indirect Cost
Name
Oklahoma Medical Research Foundation
Department
Type
DUNS #
077333797
City
Oklahoma City
State
OK
Country
United States
Zip Code
73104
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Joo, Young Bin; Lim, Jiwoo; Tsao, Betty P et al. (2018) Genetic variants in systemic lupus erythematosus susceptibility loci, XKR6 and GLT1D1 are associated with childhood-onset SLE in a Korean cohort. Sci Rep 8:9962
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Alarcón-Riquelme, Marta E; Ziegler, Julie T; Molineros, Julio et al. (2016) Genome-Wide Association Study in an Amerindian Ancestry Population Reveals Novel Systemic Lupus Erythematosus Risk Loci and the Role of European Admixture. Arthritis Rheumatol 68:932-43

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