Differential TBXA2 receptor transcript stability is dependent on the C924T polymorphism

Background: In order to better characterize the molecular mechanisms involved in processing mutated transcripts, we investigated the post-transcriptional role of the C924T polymorphism (rs4523) located in the 3' region of the TBXA2R gene. Methods and Results: Experiments of dose response with Actinomycin D on MEG-01 human cell line showed a significant decrease on cell viability that was more evident on cells treated for 24 h. In addition, we showed that treatments with 5-10 mu M, 15 mu M and 20 mu M of actinomycin D reduced cell viability by 44%, 72% and 75%, respectively, compared to the control group. Conversely, the samples treated with 1 mu M of actinomycin D did not show significant difference on cell viability as compared to the control group. Analysis of the steady state mRNA level of TBXA2R by qRT-PCR evidenced an increase in mRNA stability for the wild type (C) compared to the mutant (T) allele. Furthermore, the expression levels of TBXA2R. on wild type (CC) and mutant type (TT) patients, based on C924T polymorphism, were analyzed. The wild type showed a higher expression of TBXA2 receptor also with two different degrees of glycosylation (55 and 64 kDa), when compared to the mutant. These observations correlated with platelet aggregation, which was reduced in TT, independently of the platelet aggregation stimuli. Conclusions: The instability of the TBXA2R transcript and the lack of effect on platelet aggregation might suggest a protective role for the TBXA2R TT genotype against atherothrombosis and its complications in high-risk aspirin-treated patients.