Glycoprotein Ib activation by thrombin stimulates the energy metabolism in human platelets

Abstract

Thrombin-induced platelet activation requires substantial amounts of ATP. However, the specific contribution of each ATP-generating pathway i.e., oxidative phosphorylation (OxPhos) versus glycolysis and the biochemical mechanisms involved in the thrombin-induced activation of energy metabolism remain unclear. Here we report an integral analysis on the role of both energy pathways in human platelets activated by several agonists, and the signal transducing mechanisms associated with such activation. We found that thrombin, Trap-6, arachidonic acid, collagen, A23187, epinephrine and ADP significantly increased glycolytic flux (3–38 times vs. non-activated platelets) whereas ristocetin was ineffective. OxPhos (33 times) and mitochondrial transmembrane potential (88%) were increased only by thrombin. OxPhos was the main source of ATP in thrombin-activated platelets, whereas in platelets activated by any of the other agonists, glycolysis was the principal ATP supplier. In order to establish the biochemical mechanisms involved in the thrombin-induced OxPhos activation in platelets, several signaling pathways associated with mitochondrial activation were analyzed. Wortmannin and LY294002 (PI3K/Akt pathway inhibitors), ristocetin and heparin (GPIb inhibitors) as well as resveratrol, ATP (calcium-release inhibitors) and PP1 (Tyr-phosphorylation inhibitor) prevented the thrombin-induced platelet activation. These results suggest that thrombin activates OxPhos and glycolysis through GPIb-dependent signaling involving PI3K and Akt activation, calcium mobilization and protein phosphorylation.

Antiplatelet Effect of Carbon Monoxide Is Mediated by NAD + and ATP Depletion

“…Platelet aggregation is an energy-demanding process, 15 , 16 and recent evidence suggest a high substrate plasticity of metabolism in platelets. 17 , 19 , 42 , 43 In the present work, to our knowledge for the first time, we provide evidence that CO affords antiplatelet effects by simultaneous and efficient inhibition of 2 major ATP–generating pathways: mitochondrial respiration, attributed to the inhibition of cytochrome c oxidase, and glycolysis, ascribed to cytosolic NAD + depletion.…”

“…The effects of CO on mitochondrial respiration and glycolysis, although clearly observed for resting platelets, were more pronounced in platelets metabolically activated by thrombin, oligomycin (activating platelet glycolysis; Figure 3 A and 3 B), or FCCP (activating maximal mitochondrial respiration; Figure 1 C). Platelets in the settings of prothrombotic activation increase energetic demands 15 , 16 , 19 and, apparently in such settings, platelets also became more susceptible to the inhibitory effects of CO. Altogether, the concentration-dependent inhibition of platelet aggregation by CORM-A1 was accompanied by the concentration-dependent inhibition of platelet bioenergetics; both ensued in the same range of CORM-A1 concentrations and pertained to 2 major pathways of ATP generation, overcoming substrate plasticity of platelets.…”

“…Indeed, metabolic plasticity enables platelet aggregation even after inhibition of a single metabolic pathway, 16 , 19 because platelets use diverse metabolic fuels—not only glucose, free fatty acids and glutamine, but also glycogen, citrate (added to the blood during collection), albumin, and acetate. 17 , 19 , 42 , 44 Recently, Ravi et al 19 demonstrated that the activation of platelets with thrombin results in metabolic reprogramming, leading to increased aerobic glycolysis, fatty acid oxidation and glutaminolysis, which all compensate each other.…”

“…Platelet aggregation is an energy-demanding process. 15 , 16 In resting or activated states, platelets draw energy from oxidative phosphorylation and glycolysis. 17 – 19 However, besides a couple of works describing altered bioenergetics of platelets derived from patients with sickle cell disease, 20 asthma, 21 sepsis, 22 Parkinson disease 23 or diabetes mellitus, 24 still little is known about the role of metabolism in the regulation of platelets’ function.…”

Peculiarities of Platelet Metabolism in Patients with Acute Coronary Syndrome with Anxiety–Depressive Disorders and Informativity of Enzymes in the Forecast of Development of Cardiovascular Complications

“…Taking into consideration the fact that platelets make a major contribution into the pathogenesis of ACS, the research of metabolic activity of these cells is of a great significance. The synthesis of surface receptors, biologically active substances that are produced by platelets, the condition of cell membranes directly depends on the activity of intracellular processes that in its turn predetermines the reactivity of homeostasis system as a whole including during pathophysiological processes [ 15 , 16 ]. Oxidoreductases have key positions of main metabolic paths.…”