Identification of a functional genetic variant driving racially dimorphic platelet gene expression of the thrombin receptor regulator, PCTP

Xianguo Kong; Lukas M. Simon; Michael Holinstat; Chad A. Shaw; Paul F. Bray; Leonard C. Edelstein

doi:10.1160/TH16-09-0692

Thrombosis and Haemostasis, Table of Contents

Thromb Haemost 2017; 117(05): 962-970
DOI: 10.1160/TH16-09-0692

Cellular Haemostasis and Platelets

Schattauer GmbH

Identification of a functional genetic variant driving racially dimorphic platelet gene expression of the thrombin receptor regulator, PCTP

Xianguo Kong

¹The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA

,

Lukas M. Simon

²Department of Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, USA

,

Michael Holinstat

³Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, USA

,

Chad A. Shaw

²Department of Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, USA

⁴Department of Statistics, Rice University, Houston, Texas, USA

,

Paul F. Bray

¹The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA

,

Leonard C. Edelstein

¹The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA

› Author Affiliations

Abstract

Summary

Platelet activation in response to stimulation of the Protease Activated Receptor 4 (PAR4) receptor differs by race. One factor that contributes to this difference is the expression level of Phosphatidylcholine Transfer Protein (PCTP), a regulator of platelet PAR4 function. We have conducted an expression Quantitative Trait Locus (eQTL) analysis that identifies single nucleotide polymorphisms (SNPs) linked to the expression level of platelet genes. This analysis revealed 26 SNPs associated with the expression level of PCTP at genome-wide significance (p < 5×10^–8). Using annotation from ENCODE and other public data we prioritised one of these SNPs, rs2912553, for functional testing. The allelic frequency of rs2912553 is racially-dimorphic, in concordance with the racially differential expression of PCTP. Reporter gene assays confirmed that the single nucleotide change caused by rs2912553 altered the transcriptional potency of the surrounding genomic locus. Electromobility shift assays, luciferase assays, and overexpression studies indicated a role for the megakaryocytic transcription factor GATA1. In summary, we have integrated multi-omic data to identify and functionalise an eQTL. This, along with the previously described relationship between PCTP and PAR4 function, allows us to characterise a genotype-phenotype relationship through the mechanism of gene expression.

Keywords

Platelets - genetics - PAR4 - PCTP - eQTL

Full Text

References

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