Methylation of platelet F2RL3 gene provides a major mechanism for smoking-induced coronary thrombosis and cardiovascular disease risk

Rationale
One of the most compelling possible explanations of the relationship between smoking and CVD risk is the impact of exposure to tobacco smoke on platelet activity and thrombogenesis. Work in the Caerphilly Prospective Study (CaPS) has shown that an index of platelet sensitivity based on whole blood responsiveness to adenosine diphosphate (ADP) induced coagulation and platelet aggregation properties measured in platelet rich plasma are related to a history of MI and ECG diagnosed IHD. There have been observations of acute effects of smoking on platelet aggregation, however little detailed examination of the impact of either long-term smoking or cessation on measurements of clotting directly. A recent small age-matched study with self-reported smoking data gave clear evidence for differential methylation by smoking status at F2RL3. This is of relevance for cardiovascular health as it codes for PAR4 which is one of two primary receptors for thrombin expressed on platelets.

Aims & Objectives
(i) Explore the relationship between methylation status at F2RL3 and cardiovascular intermediates, coagulation, platelet activity and disease outcome.
(ii) Explore the relationship between methylation status at F2RL3 and cessation/reduction of smoking.
(iii) Explore other effects of smoking on the epigenome and their impact on health.

Methods
Methylation levels at F2RL3 and an exhaustive cardiovascular diseases risk phenotype profiling will be examined in relevant studies in Bristol. Available studies have extensive intermediate cardiovascular related health data available from adults aged 47 to 80. These data will allow a systematic breakdown of the relationship between smoking, differential methylation and markers of intermediate cardiovascular risk. |External collaboration will also allowed the scoring of methylation status in large collections with incident records of ischaemic heart disease which will be valuable in the translation of these effects.

With this, an examination of the impact of variation in methylation at specific loci and smoking cessation on the patterns of methylation at F2RL3 specifically in prospectively collected samples from The Avon Longitudinal Study of Parents and Children (www.bris.ac.uk/alspac) will allow detailed examination of the impact of smoking and related biological changes.