Atorvastatin-mediated inhibition of prenylation of Rab27b and Rap1a in platelets attenuates their prothrombotic capacity and modulates clot structure.

What is the context? Statins such as Atorvastatin (ATV) are 3-hydroxy, 3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which block the cholesterol biosynthetic pathway to lower total serum levels and LDL-cholesterol.The cholesterol pathway also provides a supply of isoprenoids (farnesyl and geranylgeranyl) for the prenylation of signaling molecules, which include the families of Ras and Rho small GTPases.Prenyl groups provide a membrane anchor that is essential for the correct membrane localization and function of these proteins.Statins deplete cells of lipid geranylgeranyl diphosphate (GGPP) thereby inhibiting progression of the mevalonate pathway and prenylation of proteins.Rab27b and Rap1 are small GTPase proteins in platelets that are involved in the secretion of platelet granules and integrin activation.What is new?In this study, we found that ATV impairs prenylation of Rab27b and Rap1a and attenuates platelet function.These effects were partially rescued by GGPP, indicating the involvement of the mevalonate pathway.Platelet aggregation and degranulation was significantly attenuated by ATV.The impact of statins on platelet function altered clot formation, structure and contraction generating a clot that was more susceptible to degradation.What is the impact?This study demonstrates a novel mechanism whereby statins alter platelet responses and ultimately clot structure and stability.