Total Synthesis of a PSGL-1 Glycopeptide Analogue for Targeted Inhibition of P-Selectin.

The high affinity interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin is mediated by a multimotif glycosulfopeptide (GSP) recognition domain consisting of clustered tyrosine sulfates and a Core 2 O-glycan terminated with sialyl LewisX (C2-O-sLeX). These distinct GSP motifs are much more common than previously appreciated within a wide variety of functionally important domains involved in protein-protein interactions. However, despite the potential of GSPs to serve as tools for fundamental studies and prospects for drug discovery, their utility has been limited by the absence of chemical schemes for synthesis on scale. Herein, we report the total synthesis of GSnP-6, an analogue of the N-terminal domain of PSGL-1, and potent inhibitor of P-selectin. An efficient, scalable, hydrogenolysis-free synthesis of C2-O-sLeX-Thr-COOH was identified by both convergent and orthogonal one-pot assembly, which afforded this crucial building block, ready for direct use in solid phase peptide synthesis (SPPS). C2-O-sLeX-Thr-COOH was synthesized in 10 steps with an overall yield of 23% from the 4-O,5-N oxazolidinone thiosialoside donor. This synthesis represents an 80-fold improvement in reaction yield as compared to prior reports, achieving the first gram scale synthesis of SPPS ready C2-O-sLeX-Thr-COOH and enabling the scalable synthesis of GSnP-6 for preclinical evaluation. Significantly, we established that GSnP-6 displays dose-dependent inhibition of venous thrombosis in vivo and inhibits vaso-occlusive events in a human sickle cell disease equivalent microvasculature-on-a-chip system. The insights gained in formulating this design strategy can be broadly applied to the synthesis of a wide variety of biologically important oligosaccharides and O-glycan bearing glycopeptides.

P-selectin and C-reactive protein in relation to home blood pressure and coronary calcification: a SCAPIS substudy.

BACKGROUND: Soluble P-selectin (sP-selectin) and high-sensitivity C-reactive protein (hsCRP) have previously been associated with hypertension, but the relation with out-of-office blood pressure (BP) and coronary artery calcification score is unknown. We aimed to examine the relationship between sP-selectin, hsCRP and home BP, as well as coronary artery calcification score and carotid artery plaques. METHODS: In the Swedish CArdioPulmonary bioImage Study (SCAPIS), 5057 randomly selected participants were evaluated with office and home BP using the semi-automatic Omron M10-IT device. For this cross-sectional study, participants with sP-selectin <4 standard deviations above mean and hsCRP <5 mg/l, representing low-grade inflammation, were included. Using generalized linear models, these inflammatory markers were evaluated in relation to BP classifications, as well as coronary artery calcification score and carotid artery plaques. RESULTS: Of participants, 4548 were included in the analyses. The median age was 57.2 (53.4-61.2) years, and 775 (17.0%) reported taking medication for hypertension. Participants in the highest quartile of sP-selectin [odds ratio (OR) 1.67, 95% confidence interval (CI) 1.40-1.98, P  < 0.001] and hsCRP [OR 2.25, (95% CI 1.89-2.60), P  < 0.001] were more likely to have sustained hypertension. Participants in the highest quartile of hsCRP were also more likely to have masked hypertension, OR (95% CI) 2.31 (1.72-3.10), P  < 0.001 and carotid artery plaques, OR (95% CI) 1.21 (1.05-1.38), P  = 0.007. CONCLUSION: Increased sP-selectin and hsCRP were independently associated with sustained hypertension. These findings indicate an association between hypertension and platelet activity, as expressed by sP-selectin.

1.8-cineole prevents platelet activation and aggregation by activating the cAMP pathway via the adenosine A2A receptor.

AIMS: Dysregulated platelet aggregation is a fatal condition in many bacterial- and virus-induced diseases. However, classical antithrombotics cannot completely prevent immunothrombosis, due to the unaddressed mechanisms towards inflammation. Thus, targeting platelet hyperactivation together with inflammation might provide new treatment options in diseases, characterized by immunothrombosis, such as COVID-19 and sepsis. The aim of this study was to investigate the antiaggregatory effect and mode of action of 1.8-cineole, a monoterpene derived from the essential oil of eucalyptus leaves, known for its anti-inflammatory proprieties. MAIN METHODS: Platelet activity was monitored by measuring the expression and release of platelet activation markers, i.e., P-selectin, CD63 and CCL5, as well as platelet aggregation, upon treatment with 1.8-cineole and stimulation with several classical stimuli and bacteria. A kinase activity assay was used to elucidate the mode of action, followed by a detailed analysis of the involvement of the adenylyl-cyclase (AC)-cyclic adenosine monophosphate (cAMP)-protein kinase A (PKA) pathway by Western blot and ELISA. KEY FINDINGS: 1.8-cineole prevented the expression and release of platelet activation markers, as well as platelet aggregation, upon induction of aggregation with classical stimuli and immunological agonists. Mechanistically, 1.8- cineole influences the activation of the AC-cAMP-PKA pathway, leading to higher cAMP levels and vasodilator-stimulated phosphoprotein (VASP) phosphorylation. Finally, blocking the adenosine A2A receptor reversed the antithrombotic effect of 1.8-cineole. SIGNIFICANCE: Given the recognized anti-inflammatory attributes of 1.8-cineole, coupled with our findings, 1.8-cineole might emerge as a promising candidate for treating conditions marked by platelet activation and abnormal inflammation.

Removal of endothelial surface-associated von villebrand factor suppresses accelerate datherosclerosis after myocardial infarction.

BACKGROUND: Thromboinflammation involving platelet adhesion to endothelial surface-associated von Willebrand factor (VWF) has been implicated in the accelerated progression of non-culprit plaques after MI. The aim of this study was to use arterial endothelial molecular imaging to mechanistically evaluate endothelial-associated VWF as a therapeutic target for reducing remote plaque activation after myocardial infarction (MI). METHODS: Hyperlipidemic mice deficient for the low-density lipoprotein receptor and Apobec-1 underwent closed-chest MI and were treated chronically with either: (i) recombinant ADAMTS13 which is responsible for proteolytic removal of VWF from the endothelial surface, (ii) N-acetylcysteine (NAC) which removes VWF by disulfide bond reduction, (iii) function-blocking anti-factor XI (FXI) antibody, or (iv) no therapy. Non-ischemic controls were also studied. At day 3 and 21, ultrasound molecular imaging was performed with probes targeted to endothelial-associated VWF A1-domain, platelet GPIbα, P-selectin and vascular cell adhesion molecule-1 (VCAM-1) at lesion-prone sites of the aorta. Histology was performed at day 21. RESULTS: Aortic signal for P-selectin, VCAM-1, VWF, and platelet-GPIbα were all increased several-fold (p < 0.01) in post-MI mice versus sham-treated animals at day 3 and 21. Treatment with NAC and ADAMTS13 significantly attenuated the post-MI increase for all four molecular targets by > 50% (p < 0.05 vs. non-treated at day 3 and 21). On aortic root histology, mice undergoing MI versus controls had 2-4 fold greater plaque size and macrophage content (p < 0.05), approximately 20-fold greater platelet adhesion (p < 0.05), and increased staining for markers of platelet transforming growth factor-ß1 signaling. Accelerated plaque growth and inflammatory activation was almost entirely prevented by ADAMTS13 and NAC. Inhibition of FXI had no significant effect on molecular imaging signal or plaque morphology. CONCLUSIONS: Plaque inflammatory activation in remote arteries after MI is strongly influenced by VWF-mediated platelet adhesion to the endothelium. These findings support investigation into new secondary preventive therapies for reducing non-culprit artery events after MI.

Erianin alleviates LPS-induced acute lung injury via antagonizing P-selectin-mediated neutrophil adhesion function.

ETHNOPHARMACOLOGICAL RELEVANCE: Dendrobium officinale Kimura et Migo, known as "Tiepi Shihu" in traditional Chinese medicine, boasts an extensive history of medicinal use documented in the Chinese Pharmacopoeia. "Shen Nong Ben Cao Jing" records D. officinale as a superior herbal medicine for fortifying "Yin" and invigorating the five viscera. Erianin, a benzidine compound, emerges as a prominent active constituent derived from D. officinale, with the pharmacological efficacy of D. officinale closely linked to the anti-inflammatory properties of erianin. AIM OF THE STUDY: Acute lung injury (ALI) is a substantial threat to global public health, while P-selectin stands out as a promising novel target for treating acute inflammatory conditions. This investigation aims to explore the therapeutic potential of erianin in ALI treatment and elucidate the underlying mechanisms. EXPERIMENTAL DESIGN: The effectiveness of erianin in conferring protection against ALI was investigated through comprehensive histopathological and biochemical analyses of lung tissues and bronchoalveolar lavage fluid (BALF) in an in vivo model of LPS-induced ALI in mice. The impact of erianin on fMLP-induced neutrophil chemotaxis was quantitatively assessed using the Transwell and Zigmond chamber, respectively. To determine the therapeutic target of erianin and elucidate their binding capability, a series of sophisticated assays were employed, including drug affinity responsive target stability (DARTS) assay, cellular thermal shift assay (CETSA), and molecular docking analyses. RESULTS: Erianin demonstrated a significant alleviation of LPS-induced acute lung injury, characterized by reduced total cell and neutrophil counts and diminished total protein contents in BALF. Moreover, erianin exhibited a capacity to decrease proinflammatory cytokine production in both lung tissues and BALF. Notably, erianin effectively suppressed the activation of NF-κB signaling in the lung tissues of LPS- challenged mice; however, it did not exhibit in vitro inhibitory effects on inflammation in LPS-induced human pulmonary microvascular endothelial cells (HPMECs). Additionally, erianin blocked the adhesion and rolling of neutrophils on HPMECs. While erianin did not influence endothelial P-selectin expression or cytomembrane translocation, it significantly reduced the ligand affinity between P-selectin and P-selectin glycoprotein ligand-1 (PSGL-1). CONCLUSIONS: Erianin inhibits P-selectin-mediated neutrophil adhesion to activated endothelium, thereby alleviating ALI. The present study highlights the potential of erianin as a promising lead for ALI treatment.

Proteomic profiling for biomarker discovery in heparin-induced thrombocytopenia.

ABSTRACT: New analytical techniques can assess hundreds of proteins simultaneously with high sensitivity, facilitating the observation of their complex interplay and role in disease mechanisms. We hypothesized that proteomic profiling targeting proteins involved in thrombus formation, inflammation, and the immune response would identify potentially new biomarkers for heparin-induced thrombocytopenia (HIT). Four existing panels of the Olink proximity extension assay covering 356 proteins involved in thrombus formation, inflammation, and immune response were applied to randomly selected patients with suspected HIT (confirmed HIT, n = 32; HIT ruled out, n = 38; and positive heparin/platelet factor 4 [H/PF4] antibodies, n = 28). The relative difference in protein concentration was analyzed using a linear regression model adjusted for sex and age. To confirm the test results, soluble P-selectin was determined using enzyme-linked immunosorbent assay (ELISA) in above mentioned patients and an additional second data set (n = 49). HIT was defined as a positive heparin-induced platelet activation assay (washed platelet assay). Among 98 patients of the primary data set, the median 4Ts score was 5 in patients with HIT, 4 in patients with positive H/PF4 antibodies, and 3 in patients without HIT. The median optical density of a polyspecific H/PF4 ELISA were 3.0, 0.9, and 0.3. Soluble P-selectin remained statistically significant after multiple test adjustments. The area under the receiver operating characteristic curve was 0.81 for Olink and 0.8 for ELISA. Future studies shall assess the diagnostic and prognostic value of soluble P-selectin in the management of HIT.

Asymmetric dimethylarginine correlates with indicators of prethrombotic state in patients with nonvalvular atrial fibrillation.

OBJECTIVE: The mechanism of asymmetric dimethylarginine (ADMA) in thrombosis in patients with nonvalvular atrial fibrillation (NVAF) is still unclear. Our aim was to investigate the relationship between ADMA and indicators of prethrombotic state in NVAF patients and to analyze the predictive role of ADMA in NVAF thrombosis. METHODS: A total of 192 NVAF patients were continuously selected from January 2023 to October 2023. Plasma ADMA levels were measured by high-performance liquid chromatography. P-selectin (P-sel), von Willebrand factor (vWF), D-dimer (D-D), and plasminogen activator inhibitor-1 (PAI-1) levels were measured by enzyme-linked immunosorbent assay (ELISA). Nitric oxide (NO) levels were measured by the nitrate reductase assay for plasma nitrite/nitrate, then the Griess method (Shanghai Hailian Biotechnology Co., Shanghai, China) was used to calculate plasma NO levels. RESULTS: In our study, ADMA levels were significantly elevated and positively correlated with P-sel, vWF, D-D, and PAI-1, whereas NO levels were significantly negatively correlated with these prethrombotic factors in NVAF. Furthermore, multifactorial logistic regression analysis showed that ADMA and LA diameter were independent predictors of high thrombosis risk (CHA2DS2-VASc ≥2 score) in patients with NVAF. CONCLUSIONS: Our findings suggested that ADMA correlated with the prethrombotic state in NVAF and that reduction of ADMA levels in NVAF patients may be a novel therapeutic strategy for thrombosis risk reduction.

Apolipoprotein A-IV polymorphisms Q360H and T347S attenuate its endogenous inhibition of thrombosis.

Platelets are small anucleate cells that play a key role in thrombosis and hemostasis. Our group previously identified apolipoprotein A-IV (apoA-IV) as an endogenous inhibitor of thrombosis by competitive blockade of the αIIbß3 integrin on platelets. ApoA-IV inhibition of platelets was dependent on the N-terminal D5/D13 residues, and enhanced with absence of the C-terminus, suggesting it sterically hinders its N-terminal platelet binding site. The C-terminus is also the site of common apoA-IV polymorphisms apoA-IV-1a (T347S) and apoA-IV-2 (Q360H). Interestingly, both are linked with an increased risk of cardiovascular disease, however, the underlying mechanism remains unclear. Here, we generated recombinant apoA-IV and found that the Q360H or T347S polymorphisms dampened its inhibition of platelet aggregation in human platelet-rich plasma and gel-filtered platelets, reduced its inhibition of platelet spreading, and its inhibition of P-selectin on activated platelets. Using an ex vivo thrombosis assay, we found that Q360H and T347S attenuated its inhibition of thrombosis at both high (1800s-1) and low (300s-1) shear rates. We then demonstrate a conserved monomer-dimer distribution among apoA-IV WT, Q360H, and T347S and use protein structure modelling software to show Q360H and T347S enhance C-terminal steric hindrance over the N-terminal platelet-binding site. These data provide critical insight into increased cardiovascular risk for individuals with Q360H or T347S polymorphisms.

Improving platelet function following prophylactic platelet transfusion in patients with hematological malignancies.

INTRODUCTION: Platelet transfusion is a standard treatment to prevent bleeding in patients with hematological malignancies. Although transfusions can improve platelet count, their impact on platelet function remains controversial. METHODS: We conducted flow cytometry to assess platelet function before and after transfusion and performed subgroup analyses to examine differences based on blood type, corrected count increment (CCI), and platelet microparticles. RESULTS: Overall, 50 patients who received prophylactic platelet transfusion were enrolled. CD42b expression increased, whereas CD41 expression decreased after transfusion. Apheresis platelets exhibited the lowest expression of PAC-1 and P-selectin when exposed to agonist stimulations. PAC-1 expression increased under high adenosine diphosphate (ADP) stimulation, while P-selectin expression increased under both high ADP and thrombin receptor-activating peptide stimulation. In the subgroup analysis, patients with a CCI >4500 and those with the same blood types exhibited a more significant increase in PAC-1 and P-selectin expression under agonist stimulation. When comparing apheresis platelets collected on different days, only the percentage of platelet-derived microparticles showed a significant increase. CONCLUSION: Prophylactic transfusion improved platelet function. Platelet function significantly improved in patients with a CCI >4500, those with the same blood types as that of apheresis platelets, or those with platelet-derived microparticle levels <4.7%. No significant improvement in platelet function was noted after the transfusion of different blood types with acceptable compatibility or the transfusion of incompatible blood types. Our results suggest that transfusing platelets with the same blood type remains the optimal choice.

Evaluation of soluble P-selectin as a predictive biomarker in acute symptomatic pulmonary embolism: Insights from a prospective observational study.

BACKGROUND: Soluble P-selectin (sP-selectin) has been proposed as a potential biomarker for venous thromboembolism (VTE) diagnosis with interesting results. However, its role in predicting early mortality in pulmonary embolism (PE) remains unexplored. METHODS: This observational, prospective, single-center study enrolled consecutive patients aged 18 or older with confirmed acute symptomatic PE and no prior anticoagulation. The study aims to assess the prognostic capacity of sP-selectin measured at the time of PE diagnosis for short-term mortality and major bleeding. RESULTS: A total of 196 patients, with a mean age of 69.1 years (SD 17), were included, of whom 52.6% were male. Within 30 days, 9.7% of patients (n = 19) died, and 5.1% (n = 10) suffered major bleeding. PE risk stratification revealed 4.6% (n = 9) with high-risk PE, 34.7% (n = 68) with intermediate-high-risk PE, 38.3% (n = 75) with intermediate-low-risk PE, and 22.5% (n = 44) with low-risk PE according to the European Society of Cardiology score. Mean plasma sP-selectin levels were comparable between survivors and non-survivors (489.7 ng/mL ±63 vs. 497.3 ng/mL ±51; p = .9). The ROC curve for 30-day all-cause mortality and major bleeding yielded an AUC of 0.49 (95% CI 0.36-0.63) and 0.46 (95% CI 0.24-0.68), respectively. Multivariate and survival analyses were precluded due to lack of significance. CONCLUSIONS: sP-selectin was not useful for predicting short-term mortality or major bleeding in patients with acute symptomatic pulmonary embolism. Further studies are required to clarify the role of sP-selectin in VTE, particularly in prognosticating PE outcomes.

A mouse model of the protease-activated receptor 4 Pro310Leu variant has reduced platelet reactivity.

BACKGROUND: Protease-activated receptor 4 (PAR4) mediates thrombin signaling on platelets and other cells. Our recent structural studies demonstrated that a single nucleotide polymorphism in extracellular loop 3 and PAR4-P310L (rs2227376) leads to a hyporeactive receptor. OBJECTIVES: The goal of this study was to determine how the hyporeactive PAR4 variant in extracellular loop 3 impacts platelet function in vivo using a novel knock-in mouse model (PAR4-322L). METHODS: A point mutation was introduced into the PAR4 gene F2rl3 via CRISPR/Cas9 to create PAR4-P322L, the mouse homolog to human PAR4-P310L. Platelet response to PAR4 activation peptide (AYPGKF), thrombin, ADP, and convulxin was monitored by αIIbß3 integrin activation and P-selectin translocation using flow cytometry or platelet aggregation. In vivo responses were determined by the tail bleeding assay and the ferric chloride-induced carotid artery injury model. RESULTS: PAR4-P/L and PAR4-L/L platelets had a reduced response to AYPGKF and thrombin measured by P-selectin translocation or αIIbß3 activation. The response to ADP and convulxin was unchanged among genotypes. In addition, both PAR4-P/L and PAR4-L/L platelets showed a reduced response to thrombin in aggregation studies. There was an increase in the tail bleeding time for PAR4-L/L mice. The PAR4-P/L and PAR4-L/L mice both showed an extended time to arterial thrombosis. CONCLUSION: PAR4-322L significantly reduced platelet responsiveness to AYPGKF and thrombin, which is in agreement with our previous structural and cell signaling studies. In addition, PAR4-322L had prolonged arterial thrombosis time. Our mouse model provides a foundation to further evaluate the role of PAR4 in other pathophysiological contexts.

Profiling plasma alterations of extracellular vesicles in patients with acutely decompensated cirrhosis and bacterial infection.

BACKGROUND: Extracellular vesicles (EVs) modulate inflammation, coagulation and vascular homeostasis in decompensated cirrhosis. AIM: To characterize the profile of plasmatic EVs in patients with decompensated cirrhosis and bacterial infections and evaluate the association between EVs and the development of hemostatic complications. METHODS: We measured the levels of EVs using high-sensitivity flow cytometry and phospholipid-dependent clotting time (PPL) in a prospective cohort of hospitalized patients with acutely decompensated cirrhosis with versus without bacterial infections. A separate cohort of patients with bacterial infections without cirrhosis was also enrolled. We measured endothelium-, tissue factor (TF)-bearing, platelet- and leukocyte-derived EVs. In patients with infections, EVs were reassessed upon resolution of infection. Bleeding and thrombotic complications were recorded during 1-year follow-up. RESULTS: Eighty patients with decompensated cirrhosis were recruited (40 each with and without bacterial infections). Electron microscopy confirmed the presence of plasma EVs. Despite no difference in total EVs and PPL, patients with cirrhosis and infection had significantly higher TF+ EVs, P-Selectin+ EVs (activated platelet-derived), CD14+ EVs (monocyte/macrophages derived) and CD14+ TF+ EVs versus those with cirrhosis without infection. Upon infection resolution, levels of these EVs returned to those without infection. Patients with infections showed a significant association between reduced P-Selectin+ EVs and bleeding complications (HR 8.0 [95%CI 1.3-48.1]), whereas high levels of leukocyte-derived EVs (CD45+) and CD14+ EVs were significantly associated with thrombotic complications (HR 16.4 [95%CI 1.7-160] and 10.9 [95%CI 1.13-106], respectively). Results were confirmed in a validation cohort. CONCLUSION: Bacterial infections are associated with particular alterations of plasma EVs profile in decompensated cirrhosis. Bacterial infections trigger the release of EVs originating from various cell types, which may tip the precarious hemostatic balance of patients with acutely decompensated cirrhosis towards hyper- or hypocoagulability.

Comprehensive investigation of platelet function in patients with cirrhosis.

Cirrhosis presents with thrombocytopenia and possibly thrombocytopathy. Previous studies exploring platelet function gave conflicting results and most controversies are explained by the variety of methods employed for investigation. We sought to assess in-vitro the overall platelet function in cirrhosis. We investigated 34 patients by using the following tests. (i)Aggregometry. (ii)Measurement of the content of platelet granules. (iii)Cytometric platelet activation. (iv)Plasmatic markers of in-vivo platelet activation. (v)Platelet procoagulant activity by thrombin generation (TG) in platelet-rich plasma (PRP). TG measured in PRP for patients and controls was similar. Platelets from patients with cirrhosis showed reduction of aggregation and secretion of ATP. Similar results were observed for platelet activation parameters such as P-selectin expression and PAC-1 platelet binding. Plasma levels of ßeta-thromboglobulin and soluble P-selectin, were increased in patients-vs-controls. In contrast, there were no patients-vs-controls differences for plasmatic platelet-factor-4. Results are consistent with a state of in-vivo platelet activation and decreased in-vitro aggregation. Since bleeding events following invasive procedures are uncommon in cirrhosis, we speculate that in-vitro aggregometry testing does not reflect the situation occurring in-vivo. Results of the study and pathophysiological considerations support the conclusion that platelet function in cirrhosis as determined by aggregometry, although somewhat impaired, may support the overall hemostatic potential, which is needed for most invasive interventions. These conclusions are in line with the recommendations of international guidelines, warning against indiscriminate use of prophylactic preprocedural administration of platelets before invasive procedures. Decision on platelet support should not be made based on in-vitro laboratory testing for platelet function.

The rheology of interactions between leukocytes, platelets and the vessel wall in thrombo-inflammation.

Leukocytes and platelets must adhere to the wall of blood vessels to carry out their protective functions in inflammation and haemostasis. Recruitment is critically dependent on rheological variables (wall shear rate and stress, red cell aggregation and haematocrit) which affect delivery to the vessel wall as well as velocities and forces experienced there. Leukocyte recruitment is efficient only up to wall shear rates of about 300 s-1 and usually restricted to low-shear post-capillary venules in inflammation. Being smaller, platelets experience lower velocities and shear forces adjacent to the wall and can adhere at much higher shear rates for haemostasis in arteries. In addition, we found quite different effects of variations in haematocrit or red cell aggregation on attachment of neutrophils or platelets, which also assist their separate recruitment in venules or arteries. However, it has become increasingly evident that inflammatory and thrombotic responses may occur together, with platelets promoting the adhesion and activation of neutrophils and monocytes. Indeed, it is 30 years since we demonstrated that platelets could cause neutrophils to aggregate in suspension and, when attached to a surface, could support selectin-mediated rolling of all leukocytes. Thrombin-activated platelets could further induce neutrophil activation and immobilisation. In some conditions, platelets could bind to intact endothelial monolayers and capture neutrophils or monocytes. Subsequently, we found that extracellular vesicles released by activated platelets (PEV) fulfilled similar functions when deposited on surfaces or bound to endothelial cells. In murine models, platelets or PEV could act as bridges for monocytes in inflamed vessels. Thus, leukocytes and platelets are rheologically adapted for their separate functions, while novel thrombo-inflammatory pathways using platelets or PEV may underlie pathogenic leukocyte recruitment.

A physiologic roll for cell surface GlycoRNAs.

Glycosylated RNA molecules that can be bound by lectins have been demonstrated on the surfaces of leukocytes, but their physiologic function(s) was not known. A recent study (PMID 38262409) demonstrates that at least 1 function is to promote capture and rolling of neutrophils in the vasculature. Of interest, the neutrophil glycosylated RNA molecules bind to P-selectin but not E-selectin.

High expression of angiotensin-converting enzyme 2 receptor (ACE-2), transmembrane protease serine (TMPRSS), and P-selectin in platelets lead to thrombosis formation in COVID-19 patients.

OBJECTIVE: The purpose of the present study is to see if the presence of angiotensin-converting enzyme 2 (ACE-2), transmembrane serine protease 2 (TMPRSS), and P-selectin in platelets increases the risk of thrombosis in COVID-19 patients. PATIENTS AND METHODS: This was a cross-sectional study conducted in the COVID-19 isolation center between January and September 2021 and comprised 61 COVID-19-infected patients, 21 of whom were in the intensive care unit (ICU) and 40 of whom were non-ICU patients (non-ICUP) in the isolation center. The coagulation profile, as well as the ACE-2, TMPRES, and P-selectin receptors, were all assessed in addition to the complete blood count (CBC). A questionnaire was also utilized to collect social and demographic data. RESULTS: All platelet indices and coagulation profiles were significantly altered in COVID-19 ICUP and non-ICUP in this research; additionally, there is a significant association between the presence of ACE-2, P-selectin, and TMPRRS2 in COVID-19 patients with coagulation profile and platelet indices leading to hypercoagulable state. CONCLUSIONS: In summary, the interaction of ACE-2, TMPRSS, and P-selectin in platelets appears to be a key element contributing to COVID-19 severity via their impact on thrombus development. Further investigation into these pathways may provide possible treatment targets for reducing the severe consequences of the COVID-19 infection.

Differential expression of serum TM, PAF, and CD62P in patients with autologous arteriovenous fistula and the correlation with vascular access function.

BACKGROUND: End-stage renal disease (ESRD) is the final stage of chronic kidney disease (CKD). AIMS: We aimed to analyze the expression differences of serum thrombomodulin (TM), platelet-activating factor (PAF), and P-selectin (CD62P) in patients with autologous arteriovenous fistula (AVF) and the correlation with vascular access function. METHODS: The case data were retrospectively analyzed. Moreover, 160 patients with AVF maintenance hemodialysis were selected as the AVF group, and 150 healthy participants were selected as the healthy control group. According to the function of vascular access, patients in the AVF group were divided into Group A (n = 50, after the first establishment of AVF), Group B (n = 64, normal vascular access function after hemodialysis treatment), and Group C (n = 46, vascular access failure). Pearson analysis was conducted to explore the correlation between serum TM, PAF, CD62P content, and vascular pathological examination indicators, to evaluate the value of TM, PAF, and CD62P levels in predicting vascular access failure in patients with AVF. RESULTS AND DISCUSSION: The serum levels of TM, PAF, and CD62P were positively correlated with the expressions of CD68 and MCP-1, respectively (p < .001). Serum TM was positively correlated with the levels of PAF and CD62P (p < .001), and PAF was positively correlated with the levels of CD62P (p < .001), respectively. Serum levels of TM, PAF and CD62P were risk factors for vascular access failure in AVF patients (p < .05). The area under the curve of serum TM, PAF and CD62P levels in predicting vascular access failure in AVF patients was 0.879. CONCLUSION: The serum levels of TM, PAF, and CD62P in AVF patients were correlated with the vascular access function of AVF patients, which was very important for maintaining the stability of vascular access function, and had certain value in predicting vascular access failure/disorder in AVF patients, and could be popularized and applied.

Antibody targeting of surface P-selectin glycoprotein ligand 1 leads to lymphoma apoptosis and tumorigenesis inhibition.

Lymphomas are a heterogeneous group of diseases that originate from T, B or natural killer cells. Lymphoma treatment is based on chemotherapy, radiotherapy, and monoclonal antibody (mAb) or other immunotherapies. The P-selectin glycoprotein ligand 1 (PSGL-1) is expressed at the surface of hematological malignant cells and has been shown to have a pro-oncogenic role in multiple myeloma and lymphoma. Here, we investigated the expression and therapeutic potential of PSGL-1 in T and B cell lymphomas. By flow cytometry analysis, we found that PSGL-1 was expressed in both T and B cell-derived lymphoma cell lines but generally at higher levels in T cell lymphoma cell lines. For most T and B cell-derived lymphoma cell lines, in vitro targeting with the PL1 mAb, which recognizes the PSGL-1 N-terminal extracellular region and blocks functional interactions with selectins, resulted in reduced cell viability. The PL1 mAb pro-apoptotic activity was shown to be dose-dependent, to be linked to increased ERK kinase phosphorylation, and to be dependent on the MAP kinase signaling pathway. Importantly, anti-PSGL-1 treatment of mice xenografted with the HUT-78 cutaneous T-cell lymphoma cell line resulted in decreased tumor growth, had no effect on in vivo proliferation, but increased the levels of apoptosis in tumors. Anti-PSGL-1 treatment of mice xenografted with a Burkitt lymphoma cell line that was resistant to anti-PSGL-1 treatment in vitro, had no impact on tumorigenesis. These findings show that PSGL-1 antibody targeting triggers lymphoma cell apoptosis and substantiates PSGL-1 as a potential target for lymphoma therapy.

Serum VEGF, P-Selectin, HDL-C, Platelet Index, and Coagulation Function Index in Deep Vein Thrombosis after Traumatic Fracture.

BACKGROUND: The goal was to investigate the relationship between serum vascular endothelial growth factor (VEGF), P-selectin, high-density lipoprotein cholesterol (HDL-C), platelet parameters, and coagulation function indexes and postoperative deep vein thrombosis (DVT) in patients with traumatic fracture. METHODS: A total of 150 patients with traumatic fractures after DVT were selected as the DVT group, and 150 patients with traumatic fractures without DVT during the same period were selected as the non-DVT group. Serum VEGF, P-selectin, HDL-C, platelet parameters including platelet count (PLT), mean platelet volume (MPV), platelet distribution width (PDW), plateletcrit (PCT), platelet large cell ratio (P-LCR), and plasma coagulation function indexes including thrombin time (TT), prothrombin time (PT), activated partial thrombin time (APTT), fibrinogen (FIB), and D-dimer (D-D) were measured. Pearson's correlation was performed to analyze the correlation between serum VEGF, P-selectin, and coagulation function indexes, and binary logistic regression was used to analyze the risk factors of DVT. RESULTS: Serum VEGF and P-selectin in the DVT group were higher while HDL-C was lower than those in the non-DVT group (p < 0.05). Serum VEGF and P-selectin were negatively correlated with plasma D-D and FIB (p < 0.05), and serum HDL-C was negatively correlated (p < 0.05). Compared with the non-DVT group, MPV, PDW, and P-LCR in the DVT group were decreased (p < 0.05). Multivariate logistic regression analysis showed that P-LCR was a risk factor for postoperative DVT in patients with traumatic fractures (p < 0.05). CONCLUSIONS: Serum VEGF and P-selectin are higher and HDL-C is lower in patients with DVT after postoperative traumatic fracture than in patients without DVT. Combined detection of serum VEGF, P-selectin, HDL-C, and coagulation function indexes may help to reduce the risk of DVT. Platelet parameters (MPV, PDW, P-LCR) have certain reference values for the clinical diagnosis and disease evaluation of DVT.