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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
1   The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
,
Lukas M. Simon
2   Department of Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, USA
,
Michael Holinstat
3   Department of Pharmacology, University of Michigan, Ann Arbor, Michigan, USA
,
Chad A. Shaw
2   Department of Structural and Computational Biology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas, USA
4   Department of Statistics, Rice University, Houston, Texas, USA
,
Paul F. Bray
1   The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
,
Leonard C. Edelstein
1   The Cardeza Foundation for Hematologic Research and the Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
› Author Affiliations Financial support: This study was supported by United States National Institutes of Health Grants R01HL128234 and R01MD007880.
Further Information

Publication History

Received: 09 September 2016

Accepted after major revision: 12 February 2017

Publication Date:
13 November 2017 (online)

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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
 

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