Differential TBXA2 receptor transcript stability is dependent on the C924T polymorphism

Model based on single-nucleotide polymorphism to discriminate aspirin resistance patients

BACKGROUND

Aspirin is widely used for preventing ischaemic events. About 20%-40% of patients have aspirin resistance (ASR), which prevents them from benefiting from aspirin medication. This study aimed to develop and validate a model based on single-nucleotide polymorphism (SNP) to distinguish ASR patients.

METHODS

We included patients with spontaneous intracerebral haemorrhage and continuing antiplatelet therapy from a multicentre, prospective cohort study as the derivation cohort. Thromboelastography (inhibition of arachidonic acid channel<50%) was used to identify ASR. Genotyping was performed to identify the ASR-related SNP. Based on the result of the logistic analysis, the aspirin resistance in the Chinese population score (ASR-CN score) was established, and its accuracy was evaluated using the area under the curve (AUC). Patients receiving dual antiplatelet therapy for unruptured intracranial aneurysm embolism were prospectively included in the validation cohort. After embolism, 30-day ischaemic events, including ischaemic stroke, new or more frequent transient ischaemic attack, stent thrombosis and cerebrovascular death, were recorded.

RESULTS

The derivation cohort included 212 patients (155 male patients and the median age as 59). 87 (41.0%) individuals were identified with ASR. The multivariate logistic analysis demonstrated six SNPs of GP1BA, TBXA2R, PTGS2 and NOS3 as risk factors related to ASR. The ASR-CN score integrating these SNPs performed well to discriminate ASR patients from non-ASR patients (AUC as 0.77). Based on the validation cohort of 372 patients receiving antiplatelet therapy after embolism (including 130 ASR patients), the ASR-CN score continued to distinguish ASR patients with good accuracy (AUC as 0.80). Patients with high a ASR-CN score were more likely to suffer from 30-day ischaemic events after embolism (OR, 1.28; 95% CI, 1.10 to 1.50; p=0.002).

CONCLUSION

GP1BA, TBXA2R, PTGS2 and NOS3 were SNPs related to ASR. The ASR-CN score is an effective tool to discriminate ASR patients, which may guide antiplatelet therapy.

CLINICAL TRIAL REGISTRATION

Surgical Treatments of Antiplatelet Intracerebral Hemorrhage cohort (unique identifier: ChiCTR1900024406, http://www.chictr.org.cn/edit.aspx?pid=40640&htm=4).

TBXA2R rs4523 G allele is associated with decreased susceptibility to Kawasaki disease

Kawasaki disease is a multi-system vasculitis and a primary cause of acquired heart disease among children. Genetic factors may increase susceptibility to Kawasaki disease. TBXA2R is a G-protein-coupled receptor that participates in tissue inflammation and is associated with susceptibility to several diseases, but its relevance in Kawasaki disease is unclear. We genotyped TBXA2R (rs1131882 and rs4523) in 694 Kawasaki disease cases and 657 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to evaluate the intensity of the associations. We found a significantly decreased risk of Kawasaki disease associated with TBXA2R rs4523 G variant genotypes (AG vs AA: adjusted OR = 0.788, 95%CI = 0.626-0.993; GG vs AA: adjusted OR = 0.459, 95%CI = 0.258-0.815; AG/GG vs AA: adjusted OR = 0.744, 95%CI = 0.595-0.929; GG vs AG/AA: adjusted OR = 0.497, 95% CI = 0.281-0.879). In the combined analysis of the two single-nucleotide polymorphisms (SNPs), we found that individuals with two unfavorable genotypes exhibited decreased risk for Kawasaki disease (adjusted OR = 0.754, 95%CI = 0.577-0.985) compared with those who did not have or one unfavorable genotypes. This cumulative effect on protection is effect-genotype dose-dependent (p_trend = 0.022). Moreover, the combined analysis indicated that the two unfavorable genotypes were associated with a decreased risk of Kawasaki disease in children 12-60 months of age, females and the subgroup with non-coronary artery lesion (NCAL) formation compared with those who did not have or one unfavorable genotypes. In conclusion, the TBXA2R rs4523 G allele may contribute to protection against Kawasaki disease and decreased risk of coronary artery aneurysm complications in a southern Chinese population.

Autophagy processes are dependent on EGF receptor signaling

Autophagy is a not well-understood conserved mechanism activated during nutritional deprivation in order to maintain cellular homeostasis. In the present study, we investigated the correlations between autophagy, apoptosis and the MAPK pathways in melanoma cell lines. We demonstrated that during starvation the EGF receptor mediated signaling activates many proteins involved in the MAPK pathway. Our data also suggest a previously unidentified link between the EGFR and Beclin-1 in melanoma cell line. We demonstrated that, following starvation, EGFR binds and tyrosine-phosphorylates Beclin-1, suggesting that it may play a key inhibitory role in the early stage of starvation, possibly through the Beclin-1 sequestration. Furthermore, EGFR releases Beclin-1 and allows initiating steps of the autophagic process. Interestingly enough, when the EGFR pathway was blocked by anti-EGF antibodies, immunoprecipitated Beclin-1 did not bind the phospho-EGFR. In addition, an extended binding of p-Bcl2 either with Beclin-1 or with Bax was observed with a decreased activation of the stress-induced JNK kinase, thus avoiding the transduction pathways that activate autophagy and apoptosis, respectively. For this reason, we advance the hypothesis that the activation of the EGFR is a necessary event that allows the ignition and progression of the autophagic process, at least in melanoma cells.