Inhibiting the P2Y Receptor in Megakaryocytes and Platelets Suppresses Interferon-Associated Responses.

The authors investigated the impact of antiplatelet therapy on the megakaryocyte (MK) and platelet transcriptome. RNA-sequencing was performed on MKs treated with aspirin or P2Y inhibitor, platelets from healthy volunteers receiving aspirin or P2Y inhibition, and platelets from patients with systemic lupus erythematosus (SLE). P2Y inhibition reduced gene expression and inflammatory pathways in MKs and platelets.

Dynamic perioperative platelet activity and cardiovascular events in peripheral artery disease.

Objective: Patients with peripheral artery disease (PAD) undergo lower extremity revascularization (LER) for symptomatic relief or limb salvage. Despite LER, patients remain at increased risk of platelet-mediated complications, such as major adverse cardiac and limb events (MACLEs). Platelet activity is associated with cardiovascular events, yet little is known about the dynamic nature of platelet activity over time.

A Platelet Reactivity ExpreSsion Score derived from patients with peripheral artery disease predicts cardiovascular risk.

Platelets are key mediators of atherothrombosis, yet, limited tools exist to identify individuals with a hyperreactive platelet phenotype. In this study, we investigate the association of platelet hyperreactivity and cardiovascular events, and introduce a tool, the Platelet Reactivity ExpreSsion Score (PRESS), which integrates platelet aggregation responses and RNA sequencing. Among patients with peripheral artery disease (PAD), those with a hyperreactive platelet response (>60% aggregation) to 0.

Platelet RNA Biomarker of Ticagrelor-Responsive Genes Is Associated With Platelet Function and Cardiovascular Events.

Background: Identifying patients with the optimal risk:benefit for ticagrelor is challenging. The aim was to identify ticagrelor-responsive platelet transcripts as biomarkers of platelet function and cardiovascular risk.

Methods: Healthy volunteers (n=58, discovery; n=49, validation) were exposed to 4 weeks of ticagrelor with platelet RNA data, platelet function, and self-reported bleeding measured pre-/post-ticagrelor.

Plasma tissue-type plasminogen activator is associated with lipoprotein(a) and clinical outcomes in hospitalized patients with COVID-19.

Background: Patients with COVID-19 have a higher risk of thrombosis and thromboembolism, but the underlying mechanism(s) remain to be fully elucidated. In patients with COVID-19, high lipoprotein(a) (Lp(a)) is positively associated with the risk of ischemic heart disease. Lp(a), composed of an apoB-containing particle and apolipoprotein(a) (apo(a)), inhibits the key fibrinolytic enzyme, tissue-type plasminogen activator (tPA).

Platelet-monocyte aggregates: molecular mediators of thromboinflammation.

Platelets, key facilitators of primary hemostasis and thrombosis, have emerged as crucial cellular mediators of innate immunity and inflammation. Exemplified by their ability to alter the phenotype and function of monocytes, activated platelets bind to circulating monocytes to form monocyte-platelet aggregates (MPA). The platelet-monocyte axis has emerged as a key mechanism connecting thrombosis and inflammation.

Modeling of clinical phenotypes in systemic lupus erythematosus based on the platelet transcriptome and FCGR2a genotype.

Background: The clinical heterogeneity of SLE with its complex pathogenesis remains challenging as we strive to provide optimal management. The contribution of platelets to endovascular homeostasis, inflammation and immune regulation highlights their potential importance in SLE. Prior work from our group showed that the Fcγ receptor type IIa (FcγRIIa)-R/H131 biallelic polymorphism is associated with increased platelet activity and cardiovascular risk in SLE.

An inflammatory transcriptomic signature in psoriasis associates with future cardiovascular events.

Background: Psoriasis is an inflammatory skin disease associated with increased cardiovascular (CV) risk, whose pathogenesis is not fully known.

Objective: We identified a transcriptomic signature in psoriasis and investigated its association with prevalent and future risk of a CV event to understand the connection between psoriasis and CV disease (CVD).

Methods: Psoriasis patients (n = 37) with a history of moderate-severe skin disease without CVD and 11 matched controls underwent whole blood RNA sequencing.

P2Y12 Inhibition Suppresses Proinflammatory Platelet-Monocyte Interactions.

Background:  Monocyte-platelet aggregates (MPAs) represent the crossroads between thrombosis and inflammation, and targeting this axis may suppress thromboinflammation. While antiplatelet therapy (APT) reduces platelet-platelet aggregation and thrombosis, its effects on MPA and platelet effector properties on monocytes are uncertain.

Objectives:  To analyze the effect of platelets on monocyte activation and APT on MPA and platelet-induced monocyte activation.

Platelet LGALS3BP as a Mediator of Myeloid Inflammation in Systemic Lupus Erythematosus.

Objective: Platelets are mediators of inflammation with immune effector cell properties and have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). This study investigated the role of platelet-associated lectin, galactoside-binding, soluble 3 binding protein (LGALS3BP) as a mediator of inflammation in SLE and as a potential biomarker associated with clinical phenotypes.

Methods: We performed RNA sequencing on platelets from patients with SLE (n = 54) and on platelets from age-, sex-, and race/ethnicity-matched healthy controls (n = 18) and measured LGALS3BP levels in platelet releasate and in circulating serum.

Aspirin for the Primary Prevention of Cardiovascular Disease: Time for a Platelet-Guided Approach.

Aspirin protects against atherothrombosis while increasing the risk of major bleeding. Although it is widely used to prevent cardiovascular disease (CVD), its benefit does not outweigh its risk for primary CVD prevention in large population settings. The recent United States Preventive Services Task Force guidelines on aspirin use to prevent CVD reflect this clinical tradeoff as well as the persistent struggle to define a population that would benefit from prophylactic aspirin therapy.

Long noncoding RNA regulates antiviral immunity in humans.

Long noncoding RNAs (lncRNAs) have emerged as critical regulators of gene expression, yet their contribution to immune regulation in humans remains poorly understood. Here, we report that the primate-specific lncRNA is induced by influenza A virus and SARS-CoV-2 infection and coordinates the expression of interferon-stimulated genes (ISGs) that execute antiviral responses. depletion in human macrophages reduces histone acetylation at regulatory regions of ISG loci and attenuates ISG expression in response to microbial stimuli.

Platelet inhibition by low-dose aspirin is not influenced by body mass or weight.

Aspirin's clinical efficacy may be influenced by body weight and mass. Although inadequate platelet inhibition by aspirin is suggested as responsible, evidence for this in non-diabetic patients is sparse. We investigated the influence of body weight and mass on aspirin's inhibition of platelet aggregation in healthy adults without diabetes.

Platelets contribute to disease severity in COVID-19.

Objective: Heightened inflammation, dysregulated immunity, and thrombotic events are characteristic of hospitalized COVID-19 patients. Given that platelets are key regulators of thrombosis, inflammation, and immunity they represent prime candidates as mediators of COVID-19-associated pathogenesis. The objective of this study was to understand the contribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to the platelet phenotype via phenotypic (activation, aggregation) and transcriptomic characterization.

Platelets amplify endotheliopathy in COVID-19.

Given the evidence for a hyperactive platelet phenotype in COVID-19, we investigated effector cell properties of COVID-19 platelets on endothelial cells (ECs). Integration of EC and platelet RNA sequencing revealed that platelet-released factors in COVID-19 promote an inflammatory hypercoagulable endotheliopathy. We identified and as transcripts enriched in COVID-19 platelets and were induced by megakaryocyte infection with SARS-CoV-2.

Chronic stress primes innate immune responses in mice and humans.

Psychological stress (PS) is associated with systemic inflammation and accelerates inflammatory disease progression (e.g., atherosclerosis).

Reshaping of the gastrointestinal microbiome alters atherosclerotic plaque inflammation resolution in mice.

Since alterations in the intestinal microbiota may induce systemic inflammation and polarization of macrophages to the M1 state, the microbiome role in atherosclerosis, an M1-driven disease, requires evaluation. We aimed to determine if antibiotic (Abx) induced alterations to the intestinal microbiota interferes with atherosclerotic plaque inflammation resolution after lipid-lowering in mice. Hyperlipidemic Apoe mice were fed a western diet to develop aortic atherosclerosis with aortas then transplanted into normolipidemic wild-type (WT) mice to model clinically aggressive lipid management and promote atherosclerosis inflammation resolution.

Inhibiting LXRα phosphorylation in hematopoietic cells reduces inflammation and attenuates atherosclerosis and obesity in mice.

Atherosclerosis and obesity share pathological features including inflammation mediated by innate and adaptive immune cells. LXRα plays a central role in the transcription of inflammatory and metabolic genes. LXRα is modulated by phosphorylation at serine 196 (LXRα pS196), however, the consequences of LXRα pS196 in hematopoietic cell precursors in atherosclerosis and obesity have not been investigated.

Platelet-conditioned media induces an anti-inflammatory macrophage phenotype through EP4.

Background: Platelets are increasingly recognized as immune cells. As such, they are commonly seen to induce and perpetuate inflammation; however, anti-inflammatory activities are increasingly attributed to them. Atherosclerosis is a chronic inflammatory condition.

β-Carotene conversion to vitamin A delays atherosclerosis progression by decreasing hepatic lipid secretion in mice.

Atherosclerosis is characterized by the pathological accumulation of cholesterol-laden macrophages in the arterial wall. Atherosclerosis is also the main underlying cause of CVDs, and its development is largely driven by elevated plasma cholesterol. Strong epidemiological data find an inverse association between plasma β-carotene with atherosclerosis, and we recently showed that β-carotene oxygenase 1 (BCO1) activity, responsible for β-carotene cleavage to vitamin A, is associated with reduced plasma cholesterol in humans and mice.