Metabolic targeting of platelets to combat thrombosis: dawn of a new paradigm?

Regulation of lipid metabolism: a new strategy for platelet storage

Transfusions of platelets are often used as prophylaxis in patients with hematologic malignancies and as treatment for active bleeding. However, platelets are in short supply due to the fact that they could only be kept for 5-7 days in vitro and they lose some of their functionality as a result of platelet storage lesions. To address this issue, refrigeration, cryopreservation and platelet additive solutions have been researched to determine their abilities to extend platelet storage duration. However, refrigerated platelets are quickly cleared after transfusion, while platelets in platelet additive solutions still present issues such as platelets quality and the risk of allergic reactions. Recent studies showed that changes in lipid metabolites during platelet storage and inadequate of fatty acid metabolism may also limit platelet shelf life and function. In this review, we address the principles of lipid metabolism during platelet storage and discuss the strategies for effective platelet storage systems. The findings of this review highlight the role of lipid metabolism during platelet storage, providing insights into future research focused on extending the preservation period and function of platelet.

In situ protein corona-camouflaged supramolecular assemblies remodel thrombotic microenvironment for improved arterial homeostasis

Arterial thrombosis is commonly accompanied by poor recanalization and high recurrence, typically caused by a fibrinolysis-resistant microenvironment. We identify elevated levels of plasminogen activator inhibitor-1 (PAI-1) and, notably, its strong correlation with inflammation in arterial thrombosis. To address this, small molecular inhibitors of PAI-1 and inflammation are used as bioregulators to restore vascular homeostasis. We design a carrier-free supramolecular system based on the bioregulators-tuned self-assembly of a near-infrared thrombus probe, which preferentially forms protein corona in situ to enhance plasma stability. Under acidic conditions and increased shear stress, the supramolecular assemblies disintegrate, enabling site-specific cargo release. In vivo, the probe accumulates 22.8-fold more in the thrombotic than contralateral artery. Functionally, this nanomedicine improves outcomes in mice with carotid artery thrombosis and chronic cerebral ischemia. Mechanistically, it down-regulates NF-κB signaling, inhibits NETosis and glycolysis, and up-regulates cGMP-mediated signaling, thereby alleviating inflammation and promoting fibrinolysis. This study offers an innovative codelivery strategy using supramolecular assemblies to advance therapies for arterial thrombosis.

Metabolic crosstalk between platelets and cancer: Mechanisms, functions, and therapeutic potential

Platelets, traditionally regarded as passive mediators of hemostasis, are now recognized as pivotal regulators in the tumor microenvironment, establishing metabolic feedback loops with tumor and immune cells. Tumor-derived signals trigger platelet activation, which induces rapid metabolic reprogramming, particularly glycolysis, to support activation-dependent functions such as granule secretion, morphological changes, and aggregation. Beyond self-regulation, platelets influence the metabolic processes of adjacent cells. Through direct mitochondrial transfer, platelets reprogram tumor and immune cells, promoting oxidative phosphorylation. Additionally, platelet-derived cytokines, granules, and extracellular vesicles drive metabolic alterations in immune cells, fostering suppressive phenotypes that facilitate tumor progression. This review examines three critical aspects: (1) the distinctive metabolic features of platelets, particularly under tumor-induced activation; (2) the metabolic crosstalk between activated platelets and other cellular components; and (3) the therapeutic potential of targeting platelet metabolism to disrupt tumor-promoting networks. By elucidating platelet metabolism, this review highlights its essential role in tumor biology and its therapeutic implications.

BAD-Glucokinase Axis Regulates Platelet Activation and Thrombosis

BACKGROUND

BAD (Bcl2-associated death promoter), a member of the Bcl2 proapoptotic family, promotes cell apoptosis by sequestering the prosurvival proteins Bcl-XL and Bcl2 from the proapoptotic proteins BAK (Bcl2 homologous antagonist/killer) and BAX (Bcl2-associated X protein) in nucleated cells. BAD is also expressed in platelets, playing a role in regulating platelet lifespan, apoptosis, and clearance. However, whether BAD regulates platelet activation and arterial thrombosis remains unclear.

METHODS

The role of BAD in platelet activation and arterial thrombosis was investigated using BAD-deficient mice (Bad-/-), in vitro functional studies, and arterial thrombosis models. The regulatory effect of BAD on platelet energy metabolism was detected using a Seahorse Extracellular Flux Analyzer. The regulatory effect of BAD on glucokinase was investigated by coimmunoprecipitation and activity measurement. The glucokinase heterozygous knockout mice (Gck+/-) and activator were used to study its role in platelet activation.

RESULTS

BAD-deficient mice (Bad-/-) and wild-type mice transfused with Bad-/- platelets displayed prolonged tail bleeding and arterial occlusion times. Bad-/- platelets exhibited decreased aggregation in response to stimulations by proteinase-activated receptor 4-activating peptide, thrombin, and U46619. Furthermore, BAD ablation suppressed platelet integrin αIIbβ3 activation, granule secretion, and clot retraction induced by these agonists. Mechanistically, BAD interacted with glucokinase, and BAD deficiency resulted in decreased platelet glucokinase activity, mitochondrial oxidative phosphorylation, and mitochondrial ATP production. The partial loss of glucokinase (Gck+/-) phenocopied platelet function defects caused by BAD deficiency, and a glucokinase activator rescued the impaired mitochondrial ATP production and function of Bad-/- platelets. Additionally, the glucokinase activator enhanced human platelet activation.

CONCLUSIONS

Our findings demonstrate the critical role of the BAD-glucokinase axis in platelet activation and thrombosis, suggesting a potential target for antithrombotic therapy.

IRAP Drives Ribosomal Degradation to Refuel Energy for Platelet Activation during Septic Thrombosis

Platelets play crucial roles in multiple pathophysiological processes after energy-dependent activation. It is puzzling how such a small cellular debris has abundant energy supply. In this study, it is shown that insulin-regulated aminopeptidase (IRAP), a type II transmembrane protein, is a key regulator for platelet activation by promoting energy regeneration during septic thrombosis. Through interaction with certain endosome membrane proteins, IRAP can not only promote granule release, but also facilitate lysosomal degradation of theoretically discarded ribosomes in an mTORC1- and S-acylation-dependent manner in activated platelets. Plentiful amino acids obtained from IRAP-mediated ribophagy are recruited to aerobic glycolysis and then promote energy metabolism reprogramming, thereby producing abundant energy for platelet life extension and prolonged activation. Consequently, targeted blocking IRAP can dramatically alleviate platelet hyperactivation and septic thrombosis.

Metabolic Pattern of Brain Death-NMR-Based Metabolomics of Cerebrospinal Fluid

The aim of this study was to gain insight into the biochemical status of cerebrospinal fluid in the presence of brain death in life-supported patients. The biochemical status was determined via in vitro NMR spectroscopy of cerebrospinal fluid (CSF) obtained by lumbar puncture from 22 patients with confirmed brain death and compared with that of 34 control patients (without neurological diseases). Forty-one NMR signals from raw CSF samples and 20 signals from lipid extracts were analyzed using univariate and multivariate statistical methods. ANOVA revealed significant differences in all analyzed signals. No single biochemical marker was found to predict brain death. The CSF metabolic profiles of patients who died differed significantly from those of patients in the control group. There were many statistically significantly different compounds, including amino acids, ketone bodies, lactate, pyruvate, citrate, guanidinoacetate, choline, and glycerophosphocholine. Analysis of lipids revealed significant differences in cholesterol, estriol, and phosphoethanolamine. Discriminant analysis allows the analysis of metabolic profiles instead of single biomarkers of cerebrospinal fluid compounds. The results of our analysis allowed us to split the groups-the control group, which consisted of patients with a normal biochemical CSF composition, and the brain death group-with confirmed brain death.

MITOCDNB DECREASES PLATELET ACTIVATION THROUGH ITS SELECTIVE ACTION ON MITOCHONDRIAL THIOREDOXIN REDUCTASE

Platelet inhibition is a fundamental objective to prevent and treat thrombus formation. Platelet activation depends on mitochondrial function. This study aims to identify a new mitochondria-targeting compound with antiplatelet activity at safe concentrations in vitro. Cytotoxicity and viability tests were performed on human platelets from volunteer donors, together with experiments on aggregation, platelet activation, mitochondrial function, mitochondrial respiration, and thioredoxin reductase 2 (TrxR2) enzymatic activity in isolated platelet mitochondria. The compound MitoCDNB, corresponding to the molecule 5-chloro-2,4-dinitrophenylamino linked with triphenylphosphonium cation (TPP+) by a butyl chain and methanesulfonate as the counterion, was evaluated. MitoCDNB demonstrates potent, high mitochondria-selective antiplatelet effects that provide a novel approach to platelet inhibition with potentially minimized systemic risks. Here, we describe the first compound that inhibits platelet activation by decreasing TrxR2 enzymatic activity and collagen-stimulated maximal mitochondrial respiration, preventing aggregation and platelet activation. These results can be used to develop new antiplatelet drugs targeting mitochondria.

Metabolic landscape in venous thrombosis: insights into molecular biology and therapeutic implications

The findings of the last decade suggest a complex link between inflammatory cells, coagulation, and the activation of platelets and their synergistic interaction to promote venous thrombosis. Inflammation is present throughout the process of venous thrombosis, and various metabolic pathways of erythrocytes, endothelial cells, and immune cells involved in venous thrombosis, including glucose metabolism, lipid metabolism, homocysteine metabolism, and oxidative stress, are associated with inflammation. While the metabolic microenvironment has been identified as a marker of malignancy, recent studies have revealed that for cancer thrombosis, alterations in the metabolic microenvironment appear to also be a potential risk. In this review, we discuss how the synergy between metabolism and thrombosis drives thrombotic disease. We also explore the great potential of anti-inflammatory strategies targeting venous thrombosis and the complex link between anti-inflammation and metabolism. Furthermore, we suggest how we can use our existing knowledge to reduce the risk of venous thrombosis.

Deletion of pyruvate dehydrogenase kinases reduces susceptibility to deep vein thrombosis in mice

ABSTRACT

Neutrophils contribute to deep vein thrombosis (DVT) by releasing prothrombotic neutrophil extracellular traps (NETs). NET formation (known as NETosis) is an energy-intensive process that requires an increased rate of aerobic glycolysis. The metabolic enzymes pyruvate dehydrogenase kinases (PDKs) inhibit the pyruvate dehydrogenase complex to divert the pyruvate flux from oxidative phosphorylation toward aerobic glycolysis. Herein, we identified that the combined deletion of PDK2 and PDK4 (PDK2/4-/-) renders mice less susceptible to DVT (measured by thrombus incidence, weight, and length) in the inferior vena cava-stenosis model at day 2 after surgery. Compared with wild-type (WT) mice, the venous thrombus obtained from PDK2/4-/- mice exhibited reduced citrullinated histone content, a known marker of NETs. In line with in vivo observations, phorbol 12-myristate 13-acetate (PMA)-stimulated PDK2/4-/- neutrophils displayed reduced NETosis and secretion of cathepsin G and elastase compared with PMA-stimulated WT neutrophils. The formation of platelet aggregates mediated by PMA-stimulated PDK2/4-/- neutrophils were significantly reduced compared with PMA-stimulated WT neutrophils. Finally, PDK2/4-/- neutrophils exhibited reduced levels of intracellular Ca2+ concentration, extracellular signal-regulated kinase 1/2 (Erk1/2) phosphorylation, and glycolytic proton efflux rate (a measure of aerobic glycolysis), known to facilitate NETosis. Together, these findings elucidate, to our knowledge, for the first time, the fundamental role of PDK2/4 in regulating NETosis and acute DVT.

Platelet Metabolic Profiling Reveals Glycolytic and 1-Carbon Metabolites Are Essential for GP VI-Stimulated Human Platelets-Brief Report

BACKGROUND

Evolving evidence suggests that besides signaling pathways, platelet activation involves a complex interplay between metabolic pathways to support thrombus growth. Selective targeting of metabolic checkpoints may inhibit platelet activation and provide a novel antiplatelet strategy. We, therefore, examined global metabolic changes that occur during the transition of human platelets from resting to an activated state to identify metabolites and associated pathways that contribute to platelet activation.

METHODS

We performed metabolic profiling of resting and convulxin-stimulated human platelet samples. The differential levels, pathway analysis, and PCA (principal component analysis) were performed using Metaboanalyst. Metascape was used for metabolite network construction.

RESULTS

Of the 401 metabolites identified, 202 metabolites were significantly upregulated, and 2 metabolites were downregulated in activated platelets. Of all the metabolites, lipids scored highly and constituted ≈50% of the identification. During activation, aerobic glycolysis supports energy demand and provides glycolytic intermediates required by metabolic pathways. Consistent with this, an important category of metabolites was carbohydrates, particularly the glycolysis intermediates that were significantly upregulated compared with resting platelets. We found that lysophospholipids such as 1-palmitoyl-GPA (glycero-3-phosphatidic acid), 1-stearoyl-GPS (glycero-3-phosphoserine), 1-palmitoyl-GPI (glycerophosphoinositol), 1-stearoyl-GPI, and 1-oleoyl-GPI were upregulated in activated platelets. We speculated that platelet activation could be linked to 1-carbon metabolism, a set of biochemical pathways that involve the transfer and use of 1-carbon units from amino acids, for cellular processes, including nucleotide and lysophospholipid synthesis. In alignment, based on pathway enrichment and network-based prioritization, the metabolites from amino acid metabolism, including serine, glutamate, and branched-chain amino acid pathway were upregulated in activated platelets, which might be supplemented by the high levels of glycolytic intermediates.

CONCLUSIONS

Metabolic analysis of resting and activated platelets revealed that glycolysis and 1-carbon metabolism are necessary to support platelet activation.