Abstract 347: Cigarette Smoking Associated Changes on Platelet Surface

Abstract

Thirty percent of all deaths from coronary heart disease each year in the US are attributable to cigarette smoking. The acute effects of smoking on the cardiovascular systems are associated with arterial thrombosis. Cigarette smoking produces central nervous system-mediated activation of the sympathetic nervous system, which stimulates secretion of pro-thrombotic molecules, serotonin (5-HT) and catecholamines into the blood at supraphysiological levels. 5-HT and catecholamines activate their platelet-specific receptors in an additive manner to change the platelet biology and physiology. Our studies of blood samples from smokers (collected just after smoking) showed several-fold elevation in plasma 5-HT and catecholamines, and platelet aggregation. To explore smoking-associated changes on platelets, the plasma membrane glycans and proteins were eluted and analyzed in MALDI-MS and LC-MS, respectively. The surface glycans of nonsmokers’ platelets were high-mannose-type but those of smokers’ platelets were on smokers’, sialylated N-glycans. Removing the N-glycan counteracted smoking-mediated platelet aggregation, suggesting that N-glycans play a role in adhesiveness of the platelet surface. MS analysis of the membrane proteins identified enzymes and proteins exclusively on smokers’ platelet plasma membrane. These included enzymes involved in glycan biosynthesis and proteins important in membrane trafficking of secretory vesicles. We hypothesize that, upon smoking, glycosylation enzymes normally sequestered in intracellularly, are translocated to the plasma membrane to induce changes in surface glycans. Interestingly, we showed that treating nonsmokers’ platelets with 5-HT and catecholamines predisposed them to a prothrombotic state. Furthermore, pharmacological blockade of receptors for 5-HT or catecholamines counteracted the 5-HT-catecholamine-mediated aggregation and alterations in level and composition of surface glycans. Achieving our proposed aims potentially will provide novel biomarkers and pharmacological targets for preventing and treating smoking-associated thrombosis.