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. RNA sequencing was used to discover platelet genes affected by ticagrelor, and a subset of the most informative was summarized into a composite score and tested for validation. This score was further analyzed (1) in CD34+ megakaryocytes exposed to an P2Y12 inhibitor in vitro, (2) with baseline platelet function in healthy controls, (3) in peripheral artery disease patients (n=139) versus patient controls (n=30) without atherosclerosis, and (4) in patients with peripheral artery disease for correlation with atherosclerosis severity and risk of incident major adverse cardiovascular and limb events. RESULTS: Ticagrelor exposure differentially expressed 3409 platelet transcripts. Of these, 111 were prioritized to calculate a Ticagrelor Exposure Signature score, which ticagrelor reproducibly increased in discovery and validation cohorts. Ticagrelor's effects on platelets transcripts positively correlated with effects of P2Y12 inhibition in primary megakaryocytes. In healthy controls, higher baseline scores correlated with lower baseline platelet function and with minor bleeding while receiving ticagrelor. In patients, lower scores independently associated with both the presence and extent of atherosclerosis and incident ischemic events. CONCLUSIONS: Ticagrelor-responsive platelet transcripts are a biomarker for platelet function and cardiovascular risk and may have clinical utility for selecting patients with optimal risk:benefit for ticagrelor use.

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). However, whether the higher Lp(a) associates with lower tPA activity, the longitudinal changes of these parameters in hospitalized patients with COVID-19, and their correlation with clinical outcomes are unknown. Objectives: To assess if Lp(a) associates with lower tPA activity in COVID-19 patients, and how in COVID-19 populations Lp(a) and tPA change post infection. Methods: Endogenous tPA enzymatic activity, tPA or Lp(a) concentration were measured in plasma from hospitalized patients with and without COVID-19. The association between plasma tPA and adverse clinical outcomes was assessed. Results: In hospitalized patients with COVID-19, we found lower tPA enzymatic activity and higher plasma Lp(a) than that in non-COVID-19 controls. During hospitalization, Lp(a) increased and tPA activity decreased, which associates with mortality. Among those who survived, Lp(a) decreased and tPA enzymatic activity increased during recovery. In patients with COVID-19, tPA activity is inversely correlated with tPA concentrations, thus, in another larger COVID-19 cohort, we utilized plasma tPA concentration as a surrogate to inversely reflect tPA activity. The tPA concentration was positively associated with death, disease severity, plasma inflammatory, and prothrombotic markers, and with length of hospitalization among those who were discharged. Conclusion: High Lp(a) concentration provides a possible explanation for low endogenous tPA enzymatic activity, and poor clinical outcomes in patients with COVID-19.

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. MPA are elevated across the spectrum of inflammatory and autoimmune disorders, including cardiovascular disease, systemic lupus erythematosus (SLE), and COVID-19, and are positively associated with disease severity. These clinical disorders are all characterized by an increased risk of thromboembolic complications. Intriguingly, monocytes in contact with platelets become proinflammatory and procoagulant, highlighting that this interaction is a central element of thromboinflammation.

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. The study was initiated to investigate the platelet transcriptome in patients with SLE and evaluate its association across FcγRIIa genotypes and distinct clinical features. METHODS: Fifty-one patients fulfilling established criteria for SLE (mean age = 41.1 ± 12.3, 100% female, 45% Hispanic, 24% black, 22% Asian, 51% white, mean SLEDAI = 4.4 ± 4.2 at baseline) were enrolled and compared with 18 demographically matched control samples. The FCGR2a receptor was genotyped for each sample, and RNA-seq was performed on isolated, leukocyte-depleted platelets. Transcriptomic data were used to create a modular landscape to explore the differences between SLE patients and controls and various clinical parameters in the context of FCGR2a genotypes. RESULTS: There were 2290 differentially expressed genes enriched for pathways involved in interferon signaling, immune activation, and coagulation when comparing SLE samples vs controls. When analyzing patients with proteinuria, modules associated with oxidative phosphorylation and platelet activity were unexpectedly decreased. Furthermore, genes that were increased in SLE and in patients with proteinuria were enriched for immune effector processes, while genes increased in SLE but decreased in proteinuria were enriched for coagulation and cell adhesion. A low-binding FCG2Ra allele (R131) was associated with decreases in FCR activation, which further correlated with increases in platelet and immune activation pathways. Finally, we were able to create a transcriptomic signature of clinically active disease that performed significantly well in discerning SLE patients with active clinical disease form those with inactive clinical disease. CONCLUSIONS: In aggregate, these data demonstrate the platelet transcriptome provides insight into lupus pathogenesis and disease activity, and shows potential use as means of assessing this complex disease using a liquid biopsy.

Effects of the circulating environment of COVID-19 on platelet and neutrophil behavior.

Introduction: Thromboinflammatory complications are well described sequalae of Coronavirus Disease 2019 (COVID-19), and there is evidence of both hyperreactive platelet and inflammatory neutrophil biology that contributes to the thromoinflammatory milieu. It has been demonstrated in other thromboinflammatory diseases that the circulating environment may affect cellular behavior, but what role this environment exerts on platelets and neutrophils in COVID-19 remains unknown. We tested the hypotheses that 1) plasma from COVID-19 patients can induce a prothrombotic platelet functional phenotype, and 2) contents released from platelets (platelet releasate) from COVID-19 patients can induce a proinflammatory neutrophil phenotype. Methods: We treated platelets with COVID-19 patient and disease control plasma, and measured their aggregation response to collagen and adhesion in a microfluidic parallel plate flow chamber coated with collagen and thromboplastin. We exposed healthy neutrophils to platelet releasate from COVID-19 patients and disease controls and measured neutrophil extracellular trap formation and performed RNA sequencing. Results: We found that COVID-19 patient plasma promoted auto-aggregation, thereby reducing response to further stimulation ex-vivo. Neither disease condition increased the number of platelets adhered to a collagen and thromboplastin coated parallel plate flow chamber, but both markedly reduced platelet size. COVID-19 patient platelet releasate increased myeloperoxidasedeoxyribonucleic acid complexes and induced changes to neutrophil gene expression. Discussion: Together these results suggest aspects of the soluble environment circulating platelets, and that the contents released from those neutrophil behavior independent of direct cellular contact.

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. This transcriptomic signature in psoriasis versus controls was evaluated in two CVD cohorts: Women referred for cardiac catheterization with (n = 76) versus without (n = 97) myocardial infarction (MI), and patients with peripheral artery disease (n = 106) followed over 2.5 years for major adverse CV or limb events (MACLE). The association between genes differentially expressed in psoriasis and prevalent and incident CV events was assed. RESULTS: In psoriasis, median age was 44 (IQR; 34-51) years, 49% male and ACC/AHA ASCVD Risk Score of 1.0% (0.6-3.4) with no significant difference versus controls. The median psoriasis area and severity index score (PASI) was 4.0 (IQR 2.9-8.2) with 36% on biologic therapy. Overall, 247 whole blood genes were upregulated and 228 downregulated in psoriasis versus controls (p < 0.05), and 1302 genes positively and 1244 genes negatively correlated with PASI (p < 0.05). Seventy-three genes overlapped between psoriasis prevalence and PASI with key regulators identified as IL-6, IL-1ß and interferon gamma. In the CVD cohorts, 50 of 73 genes (68%) identified in psoriasis associated with prevalent MI, and 29 (40%) with incident MACLE. Key regulator transcripts identified in psoriasis and CVD cohorts included SOCS3, BCL3, OSM, PIM2, PIM3 and STAT5A. CONCLUSIONS: A whole blood transcriptomic signature of psoriasis diagnosis and severity associated with prevalent MI and incident MACLE. These data have implications for better understanding the link between psoriasis, systemic inflammation and CVD.

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. METHODS: Agonist-stimulated whole blood was incubated in the presence of P-selectin, PSGL1, PAR1, P2Y12, GP IIb/IIIa, and COX-1 inhibitors and assessed for platelet and monocyte activity via flow cytometry. RNA-Seq of monocytes incubated with platelets was used to identify platelet-induced monocyte transcripts and was validated by RT-qPCR in monocyte-PR co-incubation ± APT. RESULTS: Consistent with a proinflammatory platelet effector role, MPAs were increased in patients with COVID-19. RNA-Seq revealed a thromboinflammatory monocyte transcriptome upon incubation with platelets. Monocytes aggregated to platelets expressed higher CD40 and tissue factor than monocytes without platelets (p < 0.05 for each). Inhibition with P-selectin (85% reduction) and PSGL1 (87% reduction) led to a robust decrease in MPA. P2Y12 and PAR1 inhibition lowered MPA formation (30 and 21% reduction, p < 0.05, respectively) and decreased monocyte CD40 and TF expression, while GP IIb/IIIa and COX1 inhibition had no effect. Pretreatment of platelets with P2Y12 inhibitors reduced the expression of platelet-mediated monocyte transcription of proinflammatory SOCS3 and OSM. CONCLUSIONS: Platelets skew monocytes toward a proinflammatory phenotype. Among traditional APTs, P2Y12 inhibition attenuates 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. We investigated the association between LGALS3BP levels and the prevalence, disease severity, and clinical phenotypes of SLE and studied platelet-mediated effects on myeloid inflammation. RESULTS: Platelets from patients with SLE exhibited increased expression of LGALS3BP (fold change 4.0, adjusted P = 6.02 × 10-11 ). Platelet-released LGALS3BP levels were highly correlated with circulating LGALS3BP (R = 0.69, P < 0.0001), and circulating LGALS3BP levels were correlated with the severity of disease according to the SLE Disease Activity Index (r = 0.32, P = 0.0006). Specifically, circulating LGALS3BP levels were higher in SLE patients with lupus nephritis than in patients with inactive disease (4.0 µg/ml versus 2.3 µg/ml; P < 0.001). Interferon-α induced LGALS3BP transcription and translation in a megakaryoblastic cell line (MEG-01) in a dose-dependent manner. Recombinant LGALS3BP and platelet releasates from SLE patients enhanced proinflammatory cytokine production by macrophages. CONCLUSIONS: Our results support that platelets act as potent effector cells that contribute to the pathogenesis of SLE by secreting proinflammatory LGALS3BP, which also represents a novel biomarker of SLE clinical activity.

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. Past clinical trials of primary CVD prevention with aspirin have not included consideration of a biomarker relevant to aspirin's mechanism of action, platelet inhibition. This approach is at odds with the paradigm used in other key areas of pharmacological CVD prevention, including antihypertensive and statin therapy, which combine cardiovascular risk assessment with the measurement of mechanistic biomarkers (eg, blood pressure and LDL [low-density lipoprotein]-cholesterol). Reliable methods for quantifying platelet activity, including light transmission aggregometry and platelet transcriptomics, exist and should be considered to identify individuals at elevated cardiovascular risk due to a hyperreactive platelet phenotype. Therefore, we propose a new, platelet-guided approach to the study of prophylactic aspirin therapy. We think that this new approach will reveal a population with hyperreactive platelets who will benefit most from primary CVD prevention with aspirin and usher in a new era of precision-guided antiplatelet therapy.

Long noncoding RNA CHROMR 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 CHROMR is induced by influenza A virus and SARS-CoV-2 infection and coordinates the expression of interferon-stimulated genes (ISGs) that execute antiviral responses. CHROMR depletion in human macrophages reduces histone acetylation at regulatory regions of ISG loci and attenuates ISG expression in response to microbial stimuli. Mechanistically, we show that CHROMR sequesters the interferon regulatory factor (IRF)-2-dependent transcriptional corepressor IRF2BP2, thereby licensing IRF-dependent signaling and transcription of the ISG network. Consequently, CHROMR expression is essential to restrict viral infection of macrophages. Our findings identify CHROMR as a key arbitrator of antiviral innate immune signaling in humans.

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. Cohort one (NYU, n = 84) had light transmission aggregometry (LTA) of platelet-rich plasma to submaximal adenosine diphosphate (ADP) and arachidonic acid (AA) before and following 1 week of daily 81 mg non-enteric coated aspirin. Subjects in the validation cohort (Duke, n = 66) were randomized to 81 mg or 325 mg non-enteric coated aspirin for 4 weeks, immediately followed by 4 weeks of the other dose, with LTA to submaximal collagen, ADP, and AA before and after each dosage period. Body mass index (BMI) range was 18.0-57.5 kg/m2 and 25% were obese. Inhibition of platelet aggregation was similar irrespective of BMI, body weight and aspirin dose. There was no correlation between platelet aggregation before or after aspirin with BMI or body weight. Our data demonstrate that aspirin produces potent inhibition of direct and indirect COX1-mediated platelet aggregation in healthy adults without diabetes regardless of body weight or mass - suggesting that other mechanisms explain lower preventive efficacy of low-dose aspirin with increasing body weight/mass.

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). The mechanisms underlying stress-mediated inflammation and future health risk are poorly understood. Monocytes are key in sustaining systemic inflammation, and recent studies demonstrate that they maintain the memory of inflammatory insults, leading to a heightened inflammatory response upon rechallenge. We show that PS induces remodeling of the chromatin landscape and transcriptomic reprogramming of monocytes, skewing them to a primed hyperinflammatory phenotype. Monocytes from stressed mice and humans exhibit a characteristic inflammatory transcriptomic signature and are hyperresponsive upon stimulation with Toll-like receptor ligands. RNA and ATAC sequencing reveal that monocytes from stressed mice and humans exhibit activation of metabolic pathways (mTOR and PI3K) and reduced chromatin accessibility at mitochondrial respiration-associated loci. Collectively, our findings suggest that PS primes the reprogramming of myeloid cells to a hyperresponsive inflammatory state, which may explain how PS confers inflammatory disease risk.

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. APPROACH AND RESULTS: In a cohort of 3915 hospitalized COVID-19 patients, we analyzed blood platelet indices collected at hospital admission. Following adjustment for demographics, clinical risk factors, medication, and biomarkers of inflammation and thrombosis, we find platelet count, size, and immaturity are associated with increased critical illness and all-cause mortality. Bone marrow, lung tissue, and blood from COVID-19 patients revealed the presence of SARS-CoV-2 virions in megakaryocytes and platelets. Characterization of COVID-19 platelets found them to be hyperreactive (increased aggregation, and expression of P-selectin and CD40) and to have a distinct transcriptomic profile characteristic of prothrombotic large and immature platelets. In vitro mechanistic studies highlight that the interaction of SARS-CoV-2 with megakaryocytes alters the platelet transcriptome, and its effects are distinct from the coronavirus responsible for the common cold (CoV-OC43). CONCLUSIONS: Platelet count, size, and maturity associate with increased critical illness and all-cause mortality among hospitalized COVID-19 patients. Profiling tissues and blood from COVID-19 patients revealed that SARS-CoV-2 virions enter megakaryocytes and platelets and associate with alterations to the platelet transcriptome and activation profile.

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 S100A8 and S100A9 as transcripts enriched in COVID-19 platelets and were induced by megakaryocyte infection with SARS-CoV-2. Consistent with increased gene expression, the heterodimer protein product of S100A8/A9, myeloid-related protein (MRP) 8/14, was released to a greater extent by platelets from COVID-19 patients relative to controls. We demonstrate that platelet-derived MRP8/14 activates ECs, promotes an inflammatory hypercoagulable phenotype, and is a significant contributor to poor clinical outcomes in COVID-19 patients. Last, we present evidence that targeting platelet P2Y12 represents a promising candidate to reduce proinflammatory platelet-endothelial interactions. Together, these findings demonstrate a previously unappreciated role for platelets and their activation-induced endotheliopathy in COVID-19.

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. Gut microbial composition pre and post-transplant was altered via an enteral antibiotic or not. Post aortic transplant, after Abx treatment, while plaque size did not differ, compared to Apoe-/- mice, Abx- WT recipient mice had a 32% reduction in CD68-expressing cells (p = 0.02) vs. a non-significant 12% reduction in Abx+ WT mice. A trend toward an M1 plaque CD68-expresing cell phenotype was noted in Abx+ mice. By 16S rRNA sequence analysis, the Abx+ mice had reduced alpha diversity and increased Firmicutes/Bacteroidetes relative abundance ratio with a correlation between gut Firmicutes abundance and plaque CD68-expressing cell content (p < 0.05). These results indicate that in a murine atherosclerotic plaque inflammation resolution model, antibiotic-induced microbiome perturbation may blunt the effectiveness of lipid-lowering to reduce the content of plaque inflammatory CD68-expressing cells.

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. To assess the importance of LXRα phosphorylation, bone marrow from LXRα WT and S196A mice was transplanted into Ldlr-/- mice, which were fed a western diet prior to evaluation of atherosclerosis and obesity. Plaques from S196A mice showed reduced inflammatory monocyte recruitment, lipid accumulation, and macrophage proliferation. Expression profiling of CD68+ and T cells from S196A mouse plaques revealed downregulation of pro-inflammatory genes and in the case of CD68+ upregulation of mitochondrial genes characteristic of anti-inflammatory macrophages. Furthermore, S196A mice had lower body weight and less visceral adipose tissue; this was associated with transcriptional reprograming of the adipose tissue macrophages and T cells, and resolution of inflammation resulting in less fat accumulation within adipocytes. Thus, reducing LXRα pS196 in hematopoietic cells attenuates atherosclerosis and obesity by reprogramming the transcriptional activity of LXRα in macrophages and T cells to promote an anti-inflammatory phenotype.

Characterization of PCSK9 in the Blood and Skin of Psoriasis.

Mechanisms explaining the link between psoriasis, a proinflammatory condition, and cardiovascular disease are not fully known. PCSK9 is predominantly expressed in hepatocytes as a critical regulator of lipid metabolism, and clinical trials targeting PCSK9 reduce cardiovascular disease. Independent of its role in lipid metabolism, PCSK9 levels associate with endothelial dysfunction and predict cardiovascular events. We used two separate human psoriasis cohorts and the K14-Rac1V12-/+ murine model of psoriasis to investigate PCSK9 and cardiovascular risk in psoriasis. In both psoriasis cohorts (n = 88 and n = 20), PCSK9 levels were 20% and 13% higher than in age-, sex-, and cholesterol-matched controls, respectively (P < 0.05 for each comparison) and correlated with PASI (r = 0.43, P < 0.05). Despite no difference in hepatocyte expression, K14-Rac1V12-/+ mice demonstrated skin-specific PCSK9 staining, which was confirmed in human psoriatic lesional skin. In patients with psoriasis, PCSK9 levels correlated with impaired endothelial vascular health (e.g., early atherosclerosis, ß = 4.5, P < 0.01) and log converted coronary artery calcium score (ß = 0.30, P = 0.01), which remained significant after adjustment for Framingham risk, body mass index, and active biologic use. Taken together, these findings suggest, independent of cholesterol, an association between circulating PCSK9 and early as well as advanced stages of atherosclerosis in psoriasis.