scholarly journals Intrinsic DNA topology as a prioritization metric in genomic fine-mapping studies

2019 ◽  
Author(s):  
Hannah C. Ainsworth ◽  
Timothy D. Howard ◽  
Carl D. Langefeld
Keyword(s):  
Fine Mapping ◽  
Lupus Erythematosus ◽  
Association Studies ◽  
Prediction Method ◽  
Minor Groove ◽  
Dna Topology ◽  
Skewed Distribution ◽  
Groove Width ◽  
Functional Polymorphisms ◽  
Sequence Dependent

AbstractIn genomic fine-mapping studies, some approaches leverage annotation data to prioritize likely functional polymorphisms. However, existing annotation sources often present challenges as many: lack data for novel variants, offer no context for noncoding regions, and/or are confounded with linkage disequilibrium. We propose a novel annotation source – sequence-dependent DNA topology – as a prioritization metric for fine-mapping. DNA topology and function are well-intertwined, and as an intrinsic DNA property, it is readily applicable to any genomic region. Here, we constructed and applied, Minor Groove Width (MGW), as a prioritization metric. Using an established MGW-prediction method, we generated an MGW census for 199,038,197 SNPs across the human genome. Summarizing a SNP’s change in MGW (ΔMGW) as a Euclidean distance, ΔMGW exhibited a strongly right-skewed distribution, highlighting the infrequency of SNPs that generate dissimilar shape profiles. We hypothesized that phenotypically-associated SNPs can be prioritized by ΔMGW. We applied Bayesian and frequentist MGW-prioritization approaches to three non-coding regions associated with System Lupus Erythematosus in multiple ancestries. In two regions, including ΔMGW resolved the association to a single, trans-ancestral, SNP, corroborated by external functional data. Together, this study presents the first usage of sequence-dependent DNA topology as a prioritization metric in genomic association studies.Graphical AbstractWe hypothesize that SNPs imposing dissimilar minor groove width profiles (ΔMGW) are more likely to alter function. ΔMGW was interrogated genome-wide and then used as a weighting metric for fine-mapping associations.

scholarly journals Intrinsic DNA topology as a prioritization metric in genomic fine-mapping studies

2020 ◽  
Vol 48 (20) ◽  
pp. 11304-11321
Author(s):  
Hannah C Ainsworth ◽  
Timothy D Howard ◽  
Carl D Langefeld
Keyword(s):  
Fine Mapping ◽  
Lupus Erythematosus ◽  
Association Studies ◽  
Prediction Method ◽  
Dna Topology ◽  
Genomic Region ◽  
Skewed Distribution ◽  
Functional Polymorphisms ◽  
Coding Regions ◽  
Sequence Dependent

Abstract In genomic fine-mapping studies, some approaches leverage annotation data to prioritize likely functional polymorphisms. However, existing annotation resources can present challenges as many lack information for novel variants and/or may be uninformative for non-coding regions. We propose a novel annotation source, sequence-dependent DNA topology, as a prioritization metric for fine-mapping. DNA topology and function are well-intertwined, and as an intrinsic DNA property, it is readily applicable to any genomic region. Here, we constructed and applied Minor Groove Width (MGW) as a prioritization metric. Using an established MGW-prediction method, we generated a MGW census for 199 038 197 SNPs across the human genome. Summarizing a SNP’s change in MGW (ΔMGW) as a Euclidean distance, ΔMGW exhibited a strongly right-skewed distribution, highlighting the infrequency of SNPs that generate dissimilar shape profiles. We hypothesized that phenotypically-associated SNPs can be prioritized by ΔMGW. We tested this hypothesis in 116 regions analyzed by a Massively Parallel Reporter Assay and observed enrichment of large ΔMGW for functional polymorphisms (P = 0.0007). To illustrate application in fine-mapping studies, we applied our MGW-prioritization approach to three non-coding regions associated with systemic lupus erythematosus. Together, this study presents the first usage of sequence-dependent DNA topology as a prioritization metric in genomic association studies.

Identification of ST3AGL4, MFHAS1, CSNK2A2 and CD226 as loci associated with systemic lupus erythematosus (SLE) and evaluation of SLE genetics in drug repositioning

2018 ◽  
Vol 77 (7) ◽  
pp. 1078-1084 ◽  
Author(s):  
Yong-Fei Wang ◽  
Yan Zhang ◽  
Zhengwei Zhu ◽  
Ting-You Wang ◽  
David L Morris ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Fine Mapping ◽  
Lupus Erythematosus ◽  
Drug Repositioning ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Systemic Lupus ◽  
Genome Wide ◽  
Causal Variants

ObjectivesSystemic lupus erythematosus (SLE) is a prototype autoimmune disease with a strong genetic component in its pathogenesis. Through genome-wide association studies (GWAS), we recently identified 10 novel loci associated with SLE and uncovered a number of suggestive loci requiring further validation. This study aimed to validate those loci in independent cohorts and evaluate the role of SLE genetics in drug repositioning.MethodsWe conducted GWAS and replication studies involving 12 280 SLE cases and 18 828 controls, and performed fine-mapping analyses to identify likely causal variants within the newly identified loci. We further scanned drug target databases to evaluate the role of SLE genetics in drug repositioning.ResultsWe identified three novel loci that surpassed genome-wide significance, including ST3AGL4 (rs13238909, pmeta=4.40E-08), MFHAS1 (rs2428, pmeta=1.17E-08) and CSNK2A2 (rs2731783, pmeta=1.08E-09). We also confirmed the association of CD226 locus with SLE (rs763361, pmeta=2.45E-08). Fine-mapping and functional analyses indicated that the putative causal variants in CSNK2A2 locus reside in an enhancer and are associated with expression of CSNK2A2 in B-lymphocytes, suggesting a potential mechanism of association. In addition, we demonstrated that SLE risk genes were more likely to be interacting proteins with targets of approved SLE drugs (OR=2.41, p=1.50E-03) which supports the role of genetic studies to repurpose drugs approved for other diseases for the treatment of SLE.ConclusionThis study identified three novel loci associated with SLE and demonstrated the role of SLE GWAS findings in drug repositioning.

scholarly journals THU0017 ATTEMPTS TO LINK EXONIC GENE POLYMORPHISMS TO SYSTEMIC LUPUS ERYTHEMATOSUS (SLE)-ASSOCIATED PROTEIN MODIFIED FUNCTIONALITY: A STRUCTURAL BIOLOGY APPROACH

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 221.1-222
Author(s):  
E. Eliopoulos ◽  
G. Goulielmos ◽  
M. Matalliotakis ◽  
D. Vlachakis ◽  
T. Niewold ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Protein Structure ◽  
Molecular Modeling ◽  
Nucleic Acid ◽  
Molecular Mechanics ◽  
Lupus Erythematosus ◽  
Gene Polymorphisms ◽  
Association Studies ◽  
Systemic Lupus ◽  
Molecular Graphics

Background:Gene association studies and genome wide association studies (GWAS) have played a primary role in depicting genetic contributions to systemic lupus erythematosus (SLE) development, while accommodating the exonic polymorphisms on the protein structure level, when available, enhances our understanding of protein function modification or depletion. Linking human genetics with therapeutic targets requires the biological function of the causal gene and variant to be known.Objectives:To investigate recently identified SLE-associated functional gene polymorphisms, such asPARP1,ITGAM, TNFAIP3, NCF1, PON1, IFIH1, SH2B3andTYK2[1-4] by correlation to protein structure and function.Methods:Three-dimensional (3D) homology modeling and molecular mechanics/dynamics studies were applied for the localization of the polymorphisms under study on the respective proteins. The mutants were constructed using molecular modeling with the program Maestro (Schrodinger, LLC), which was also used to analyze the conformational changes caused by the mutation. All figures depicting 3D models were created using the molecular graphics program PyMOL V.2.2 [5].Results:Modeling revealed that rs1136410 SNP encodes the less common polymorphism Val762Ala onPARP1that reduces enzymatic activity of Poly(ADP-ribose) polymerase 1 (Figure 1),ITGAMpolymorphism rs1143679 (Arg77His) on Integrin alpha M, component of the macrophage-1 antigen complex affects protein surface recognition,TNFAIP3rs2230926 polymorphism encodes Cys instead of Phe at residue 127 of the ubiquitin editing A20 protein, while rs201802880 polymorphism of the neutrophil cytosolic factor 1 (NCF1) gene modifies the function of the cytosolic subunit of neutrophil NADPH oxidase with the mutation Arg90His.PON1is involved in the oxidative stress process that cause tissue damage observed in SLE and anti-phospholipid syndrome (APS). ThePON1Gln192Arg mutation (rs662 SNP) affects shape and recognition of the ligand recognition site as part of the evolutionary process, whileIFIH1(rs35667974) helicase C domain1 mutant I923V is located on an essential RNA beta loop interacting directly with the nucleic acid (Figure 2). Finally, the rs3184504 SNP ofSH2B3gene generates mutant Arg262Trp on SH2 adapter protein 3, acting as a signaling pathway involved in autoimmune disorders, while inTYK2 gene, one of the Janus kinases, the rs35018800 producing mutant Ala928Val modifies the ADP binding site.Figure 1.Details of the Val762 interaction where V762A mutation occurs in PARP1protein.Figure 2.Nucleic acid interacting IFIH1 helicase beta-loop where I923V mutation occurs (in purple).Conclusion:Based on several examples, we have tried to define a rational link from SLE-associated gene polymorphisms to structure and to modified function, including metagenomic analysis of SNPs, protein crystallography, protein molecular modeling, molecular mechanics and dynamics. Locating, shaping and understanding the target protein interaction interface plays a decisive role in most cases and provides clues for further pharmacological or medical actions [6].References:[1]Hur JW et al (2006). Rheumatology 45:711-7[2]Maiti AK et al (2014). Hum Mol Genet 23:4161-76[3]Shimane K et al (2010). Arthritis Rheum. 62:574-9[4]Linge P et al (2019). Ann Rheum Dis. 2019 Nov 8. pii: annrheumdis-2019-215820[5]Schrödinger LLC: The PyMOL Molecular Graphics System 2016 version 2.2. Available from: pymol.org/2/support.html[6]Plenge RM et al (2013). Nat Rev Drug Discov 12:581–94Disclosure of Interests:None declared

scholarly journals AB0013 ASSOCIATION BETWEEN STAT4 POLYMORPHISM AND MANIFESTATIONS OF SLE

2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1041.1-1041
Author(s):  
V. Agarwal ◽  
S. Kakati ◽  
P. Debbaruah
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Indian Population ◽  
Association Studies ◽  
Statistical Significance ◽  
Elevated Serum ◽  
Systemic Lupus ◽  
Cutaneous Manifestations ◽  
Genotype Group ◽  
Dsdna Antibody

Background:SNP rs7574865, located within the third intron of STAT4 gene at chromosome 2, has been associated with susceptibility to SLE among different ethnic groups.1,2 Interestingly, we recently have documented an association between this gene and susceptibility to systemic lupus erythematosus (SLE) in Indian population.3Objectives:To determine whether the STAT4 (rs7574865) SNP is associated with clinical and immunological manifestations in SLE.Methods:The study was carried out on 100 unrelated SLE (SLICC criteria 2012) patients from North-East India. Genotyping of STAT4 rs7574865 SNP was done using Taqman probe and Real-Time Polymerase chain reaction. An association study was performed between the alleles and genotypes of STAT4 rs7574865 with the clinical and immunological manifestations included in the SLE SLICC classification criteria. For all analysis, the statistical significance was fixed at 5% level of significance (p < 0.05).Results:The mean duration of illness was 2.69±2.55 years. Cases and Controls remained in Hardy-Weinberg equilibrium.The occurrence of Photosensitivity and hyperpigmentation was significantly higher in TT genotype group (97.22% and 77.77%, respectively) with p <0.001 in each case.SLE patients with nephritis (Albuminuria >500mg/24 hours) and elevated serum creatinine were both significantly higher in TT genotype group as compared to GT and GG (p< 0.001 and p=0.001 respectively).The Anti-dsDNA antibody was significantly associated with TT genotype (p <0.001).Conclusion:Our study provides evidence regarding the association between STAT4 rs7574865 gene polymorphism is risk factor for cutaneous manifestations, Lupus nephritis and Anti ds-DNA positivity in SLE. So, our findings reinforce the need for further association studies including prospective studies with larger subjects in order to replicate such findings.References:[1]Graham RR, Ph D, Hom G, Ph D, Behrens TW, Bakker PIW De, et al. and the Risk of Rheumatoid Arthritis and Systemic Lupus Erythematosus. N Engl J Med. 2007;357(10):977–86.[2]Yuan H, Feng JB, Pan HF, Qiu LX, Li LH, Zhang N, et al. A meta-analysis of the association of STAT4 polymorphism with systemic lupus erythematosus. Mod Rheumatol. 2010;20(3):257–62.[3]Gupta V, Kumar S, Pratap A, Singh R, Kumari R, Kumar S, et al. Association of ITGAM, TNFSF4, TNFAIP3 and STAT4 gene polymorphisms with risk of systemic lupus erythematosus in a North Indian population. Lupus. 2018;27(12):1973–9.Disclosure of Interests:None declared

scholarly journals CAUSALdb: a database for disease/trait causal variants identified using summary statistics of genome-wide association studies

2019 ◽  
Author(s):  
Jianhua Wang ◽  
Dandan Huang ◽  
Yao Zhou ◽  
Hongcheng Yao ◽  
Huanhuan Liu ◽  
...  
Keyword(s):  
Fine Mapping ◽  
Genetic Variants ◽  
Association Studies ◽  
Complex Trait ◽  
Genome Wide Association ◽  
Genome Wide Association Studies ◽  
Summary Statistics ◽  
Genome Wide ◽  
Credible Sets ◽  
Causal Variants

Abstract Genome-wide association studies (GWASs) have revolutionized the field of complex trait genetics over the past decade, yet for most of the significant genotype-phenotype associations the true causal variants remain unknown. Identifying and interpreting how causal genetic variants confer disease susceptibility is still a big challenge. Herein we introduce a new database, CAUSALdb, to integrate the most comprehensive GWAS summary statistics to date and identify credible sets of potential causal variants using uniformly processed fine-mapping. The database has six major features: it (i) curates 3052 high-quality, fine-mappable GWAS summary statistics across five human super-populations and 2629 unique traits; (ii) estimates causal probabilities of all genetic variants in GWAS significant loci using three state-of-the-art fine-mapping tools; (iii) maps the reported traits to a powerful ontology MeSH, making it simple for users to browse studies on the trait tree; (iv) incorporates highly interactive Manhattan and LocusZoom-like plots to allow visualization of credible sets in a single web page more efficiently; (v) enables online comparison of causal relations on variant-, gene- and trait-levels among studies with different sample sizes or populations and (vi) offers comprehensive variant annotations by integrating massive base-wise and allele-specific functional annotations. CAUSALdb is freely available at http://mulinlab.org/causaldb.

scholarly journals New Horizons in the Genetic Etiology of Systemic Lupus Erythematosus and Lupus-Like Disease: Monogenic Lupus and Beyond

2020 ◽  
Vol 9 (3) ◽  
pp. 712 ◽  
Author(s):  
Erkan Demirkaya ◽  
Sezgin Sahin ◽  
Micol Romano ◽  
Qing Zhou ◽  
Ivona Aksentijevich
Keyword(s):  
Systemic Lupus Erythematosus ◽  
Lupus Erythematosus ◽  
Current Knowledge ◽  
Association Studies ◽  
Severe Disease ◽  
Genetic Diagnosis ◽  
Genome Wide Association Studies ◽  
Systemic Lupus ◽  
Degree Relative ◽  
Adult Age

Systemic lupus erythematosus (SLE) is a clinically and genetically heterogeneous autoimmune disease. The etiology of lupus and the contribution of genetic, environmental, infectious and hormonal factors to this phenotype have yet to be elucidated. The most straightforward approach to unravel the molecular pathogenesis of lupus may rely on studies of patients who present with early-onset severe phenotypes. Typically, they have at least one of the following clinical features: childhood onset of severe disease (<5 years), parental consanguinity, and presence of family history for autoimmune diseases in a first-degree relative. These patients account for a small proportion of patients with lupus but they inform considerable knowledge about cellular pathways contributing to this inflammatory phenotype. In recent years with the aid of new sequencing technologies, novel or rare pathogenic variants have been reported in over 30 genes predisposing to SLE and SLE-like diseases. Future studies will likely discover many more genes with private variants associated to lupus-like phenotypes. In addition, genome-wide association studies (GWAS) have identified a number of common alleles (SNPs), which increase the risk of developing lupus in adult age. Discovery of a possible shared immune pathway in SLE patients, either with rare or common variants, can provide important clues to better understand this complex disorder, it’s prognosis and can help guide new therapeutic approaches. The aim of this review is to summarize the current knowledge of the clinical presentation, genetic diagnosis and mechanisms of disease in patents with lupus and lupus-related phenotypes.

scholarly journals Identification of a Cis-Acting Regulatory Polymorphism in a Eucalypt COBRA-Like Gene Affecting Cellulose Content

Genetics ◽  
2009 ◽  
Vol 183 (3) ◽  
pp. 1153-1164 ◽  
Author(s):  
Bala R. Thumma ◽  
Bronwyn A. Matheson ◽  
Deqiang Zhang ◽  
Christian Meeske ◽  
Roger Meder ◽  
...  
Keyword(s):  
Quantitative Traits ◽  
Association Studies ◽  
Allelic Expression ◽  
Cellulose Content ◽  
Nucleotide Polymorphisms ◽  
Cis Acting ◽  
Functional Polymorphisms ◽  
Functional Variants ◽  
Regulatory Polymorphism ◽  
Trait Locus

Populations with low linkage disequilibrium (LD) offer unique opportunities to study functional variants influencing quantitative traits. We exploited the low LD in forest trees to identify functional polymorphisms in a Eucalyptus nitens COBRA-like gene (EniCOBL4A), whose Arabidopsis homolog has been implicated in cellulose deposition. Linkage analysis in a full-sib family revealed that EniCOBL4A is the most strongly associated marker in a quantitative trait locus (QTL) region for cellulose content. Analysis of LD by genotyping 11 common single-nucleotide polymorphisms (SNPs) and a simple sequence repeat (SSR) in an association population revealed that LD declines within the length of the gene. Using association studies we fine mapped the effect of the gene to SNP7, a synonymous SNP in exon 5, which occurs between two small haplotype blocks. We observed patterns of allelic expression imbalance (AEI) and differential binding of nuclear proteins to the SNP7 region that indicate that SNP7 is a cis-acting regulatory polymorphism affecting allelic expression. We also observed AEI in SNP7 heterozygotes in a full-sib family that is linked to heritable allele-specific methylation near SNP7. This study demonstrates the potential to reveal functional polymorphisms underlying quantitative traits in low LD populations.

scholarly journals Host Genetics and Gut Microbiome: Perspectives for Multiple Sclerosis

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1181
Author(s):  
Alessandro Maglione ◽  
Miriam Zuccalà ◽  
Martina Tosi ◽  
Marinella Clerico ◽  
Simona Rolla
Keyword(s):  
Multiple Sclerosis ◽  
Environmental Factors ◽  
Lupus Erythematosus ◽  
Gut Microbiome ◽  
Complex Disease ◽  
Current Knowledge ◽  
Association Studies ◽  
Future Research ◽  
Genome Wide Association Studies ◽  
Host Genetics

As a complex disease, Multiple Sclerosis (MS)’s etiology is determined by both genetic and environmental factors. In the last decade, the gut microbiome has emerged as an important environmental factor, but its interaction with host genetics is still unknown. In this review, we focus on these dual aspects of MS pathogenesis: we describe the current knowledge on genetic factors related to MS, based on genome-wide association studies, and then illustrate the interactions between the immune system, gut microbiome and central nervous system in MS, summarizing the evidence available from Experimental Autoimmune Encephalomyelitis mouse models and studies in patients. Finally, as the understanding of influence of host genetics on the gut microbiome composition in MS is in its infancy, we explore this issue based on the evidence currently available from other autoimmune diseases that share with MS the interplay of genetic with environmental factors (Inflammatory Bowel Disease, Rheumatoid Arthritis and Systemic Lupus Erythematosus), and discuss avenues for future research.

Sign in / Sign up

Export Citation Format

Share Document