Their major drawback was the management of false positive results due to the large number of associations tested. This approach has been applied to investigate the genetic basis determining platelet morphology, such as mean platelet volume
or platelet count [48] and [49]. The first GWAS meta-analysis of platelet function was published in 2010 [50]. Two European ancestry cohorts of 4000 subjects in total were tested for aggregation to epinephrine, ADP and collagen. Seven loci were found to be associated with platelet aggregation results in both cohorts, with variable effect depending on the agonists (Table 1). These GKT137831 in vitro loci were also tested in an independent cohort of African ancestry and all but one of the seven loci was replicated in it. Several common genes were found (PEAR1, GP6 and ADRA2A for example) using GWAs and a candidate gene selleck inhibitor approach, although the SNPs may be different within the same locus. Platelet endothelial aggregation receptor-1 (PEAR1) is phosphorylated upon platelet activation and plays a role in the amplification process of αIIbβ3 activation [51]. It has
been shown to be related to epinephrine response, but also to ADP and collagen responses [50]. Glycoprotein VI (GP6) is a collagen receptor and, as expected, is associated with collagen-induced platelet activation. The reported SNP (producing a H322N, rs1671152) may decrease the interaction of GPVI with its downstream effectors, Fyn and Lyn pathways, and thus the subsequent collagen response [49]. The adrenoceptor α 2A (ADRA2A) is the major epinephrine receptor in platelets [49].
This latter gene is of particular importance since epinephrine-induced platelet aggregation is considered the most reliable marker of platelet reactivity [33]. Despite some plausibility related to the function of this gene, genetics alone can only explain a minority of the variance of parameters in cardiovascular diseases, such as mean platelet volume [52] or platelet reactivity [53]. Platelets are anucleated cell fragments, but they do contain rough endoplasmic reticulum and ribosomes. TCL Several studies showed that protein synthesis occurs in platelets [3] and [54]. Moreover, platelets contain a stable pool of mRNAs, which is involved in platelet function and life-span, hemostasis and inflammation [55]. In addition, this pool decreases with platelet age and is thus an indicator of platelet turnover [55]. Platelets are estimated to contain around 5000 different mRNA transcripts [55] covering approximately half of the megakaryocyte transcriptome. The content of mRNA also varies with platelet activation or certain diseases, such as systematic lupus erythematosus [55] and [56]. Platelet mRNAs are translated in different modes depending on the final protein and its role (Fig. 4). A small number of mRNAs are highly abundant and constitutively translated into proteins.