Search

Background: P2X7 receptor has emerged as a potentially superior PET imaging marker to TSPO, the gold standard for imaging glial reactivity. [11C]SMW139 is the most recently developed radiotracer to image P2X7 receptor. The aim of this study was to image reactive glia in the APP/PS1-21 transgenic (TG) mouse model of Aβ deposition longitudinally using [11C]SMW139 targeting P2X7 receptor and to compare tracer uptake to that of [18F]F-DPA targeting TSPO at the final imaging time point. TG and wild type (WT) mice underwent longitudinal in vivo PET imaging using [11C]SMW139 at 5, 8, 11, and 14 months, followed by [18F]F-DPA PET scan only at 14 months. In vivo imaging results were verified by ex vivo brain autoradiography, immunohistochemical staining, and analysis of [11C]SMW139 unmetabolized fraction in TG and WT mice. Results: Longitudinal change in [11C]SMW139 standardized uptake values (SUVs) showed no statistically significant increase in the neocortex and hippocampus of TG or WT mice, which was consistent with findings from ex vivo brain autoradiography. Significantly higher [18F]F-DPA SUVs were observed in brain regions of TG compared to WT mice. Quantified P2X7-positive staining in the cortex and thalamus of TG mice showed a minor increase in receptor expression with ageing, while TSPO-positive staining in the same regions showed a more robust increase in expression in TG mice as they aged. [11C]SMW139 was rapidly metabolized in mice, with 33% of unmetabolized fraction in plasma and 29% in brain homogenates 30 min after injection. Conclusions: [11C]SMW139, which has a lower affinity for the rodent P2X7 receptor than the human version of the receptor, was unable to image the low expression of P2X7 receptor in the APP/PS1-21 mouse model. Additionally, the rapid metabolism of [11C]SMW139 in mice and the presence of several brain-penetrating radiometabolites significantly impacted the analysis of in vivo PET signal of the tracer. Finally, [18F]F-DPA targeting TSPO was more suitable for imaging reactive glia and neuroinflammatory processes in the APP/PS1-21 mouse model, based on the findings presented in this study and previous studies with this mouse model. [ABSTRACT FROM AUTHOR]

Background Patients with atrial fibrillation and severe chronic kidney disease have higher risks of bleeding, thromboembolism, and mortality. However, optimal anticoagulant choice in these high‐risk patients remains unclear. Methods and Results Using deidentified electronic health records from the Optum Labs Data Warehouse, adults with atrial fibrillation and severe chronic kidney disease (estimated glomerular filtration rate

Objective: This study investigated the role of the P2Y12 receptor in autogenous arteriovenous fistula (AVF) failure resulting from stenosis. Methods: Stenotic venous tissues and blood samples were obtained from patients with end-stage renal disease (ESRD) together with AVF stenosis, while venous tissues and blood samples were collected from patients with ESRD undergoing initial AVF surgery as controls. Immunohistochemistry and/or immunofluorescence techniques were utilized to assess the expression of P2Y12, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein 1 (MCP-1), and CD68 in the venous tissues. The expression levels of P2Y12, TGFβ1, and MCP-1 were quantified using quantitative reverse transcription-polymerase chain reaction and western blot analyses. Double and triple immunofluorescence staining was performed to precisely localize the cellular localization of P2Y12 expression. Results: Expression levels of P2Y12, TGFβ1, MCP-1, and CD68 were significantly higher in stenotic AVF venous tissues than in the control group tissues. Double and triple immunofluorescence staining of stenotic AVF venous tissues indicated that P2Y12 was predominantly expressed in α-SMA-positive vascular smooth muscle cells (VSMCs) and, to a lesser extent, in CD68-positive macrophages, with limited expression in CD31-positive endothelial cells. Moreover, a subset of macrophage-like VSMCs expressing P2Y12 were observed in both stenotic AVF venous tissues and control venous tissues. Additionally, a higher number of P2Y12 +/TGF-β1+ double-positive cells were identified in stenotic AVF venous tissues than in the control group tissues. Conclusion: Increased expression of P2Y12 in stenotic AVF venous tissues of patients with ESRD suggests its potential involvement in the pathogenesis of venous stenosis within AVFs. [ABSTRACT FROM AUTHOR]

Pharmacological inhibition of the platelet ADP-receptor P2Y12 is a cornerstone in the prevention of atherothrombotic events in adult patients with acute coronary syndrome (ACS). Thienopyridines such as clopidogrel and prasugrel exert their antithrombotic effect by means of active metabolites that irreversibly inhibit P2Y12. Due to the short half-life of these metabolites, a subpopulation of ADP-responsive platelets will form in between dosing. With increased platelet turnover rate or poor patient compliance, the fraction of ADP-responsive platelets will increase, potentially increasing the risk for new thrombotic events. In contrast, the reversible P2Y12 inhibition produced by direct-acting ADP blockers such as ticagrelor and cangrelor inhibit the entire platelet population. In this study, we evaluated the impact of these pharmacological differences on thrombus formation in an ex vivo flow chamber model. A customized image analysis pipeline was used for automatized, large-scale identification and tracking of single platelets incorporated into the thrombus, enabling quantitative analysis of the relative contribution of inhibited and uninhibited platelets to thrombus growth and consolidation. Comparative experiments were conducted using the irreversible and reversible P2Y12 inhibitors prasugrel active metabolite (PAM) and ticagrelor, respectively. Our results show that PAM inhibited thrombus platelet recruitment more gradually than ticagrelor, with a slower onset of inhibition. Further, we show that the presence of a small fraction (<10%) of uninhibited platelets did not abrogate the antithrombotic effect of PAM to any significant extent. Finally, we demonstrate a gradual enrichment of inhibited platelets in the thrombus shell due to selective recruitment of inhibited platelets to the thrombus periphery. [ABSTRACT FROM AUTHOR]

Clopidogrel combined with aspirin is widely used in coronary artery disease (CAD) patients, while some patients exhibit high platelet activity when receiving the combined treatment. Current environmental and genetic factors could only explain part of the variability in clopidogrel efficacy. Human platelets harbor abundant miRNAs which might affect clopidogrel efficacy by regulating the expression of key proteins in the clopidogrel antiplatelet signaling pathway. This study aimed to investigate the association between platelet miRNA levels and clopidogrel efficacy. Here we recruited 508 CAD patients who underwent clopidogrel antiplatelet therapy and determined the platelet reactivity index (PRI) to evaluate antiplatelet reactivity responses to clopidogrel. Subsequently, 22 patients with extreme clopidogrel response were selected for platelet small RNA sequencing. Another 41 CAD patients taking clopidogrel were collected to verify the differentially expressed candidate miRNAs. We found the metabolic types of the CYP2C19 enzyme (based on CYP2C19 * 2 and * 3 polymorphisms) could significantly affect the PRI of CAD patients with or without percutaneous coronary intervention (PCI) in Chinese. A total of 43 miRNAs were differentially expressed in the platelets from the 22 extreme clopidogrel response samples, and 109 miRNAs were differentially expressed in the 13 CYP2C19 extensive metabolizers with extreme clopidogrel response. Platelet miR-199a-5p levels were correlated negatively with PRI after clopidogrel therapy. Studies in cultured cells revealed that miR-199a-5p inhibited the expression of VASP, a key effector protein downstream of the P2Y12 receptor. In conclusion, we found the expression of VASP could be inhibited by miR-199a-5p, and decreased platelet miR-199a-5p was associated with high on-clopidogrel platelet reactivity in CAD patients. [ABSTRACT FROM AUTHOR]

Microglia regulate anesthesia by altering the activity of neurons in specific regions of the brain via a purinergic receptor.

General anesthesia leads to a loss of consciousness and an unrousable state in patients. Although general anesthetics are widely used in clinical practice, their underlying mechanisms remain elusive. The potential involvement of nonneuronal cells is unknown. Microglia are important immune cells in the central nervous system (CNS) that play critical roles in CNS function and dysfunction. We unintentionally observed delayed anesthesia induction and early anesthesia emergence in microglia-depleted mice. We found that microglial depletion differentially regulates neuronal activities by suppressing the neuronal network of anesthesia-activated brain regions and activating emergence-activated brain regions. Thus, microglia facilitate and stabilize the anesthesia status. This influence is not mediated by dendritic spine plasticity. Instead, it relies on the activation of microglial P2Y12 and subsequent calcium influx, which facilitates the general anesthesia response. Together, we elucidate the regulatory role of microglia in general anesthesia, extending our knowledge of how nonneuronal cells modulate neuronal activities.

Objective This study investigated the role of the P2Y12 receptor in autogenous arteriovenous fistula (AVF) failure resulting from stenosis.Methods Stenotic venous tissues and blood samples were obtained from patients with end-stage renal disease (ESRD) together with AVF stenosis, while venous tissues and blood samples were collected from patients with ESRD undergoing initial AVF surgery as controls. Immunohistochemistry and/or immunofluorescence techniques were utilized to assess the expression of P2Y12, transforming growth factor-β1 (TGF-β1), monocyte chemotactic protein 1 (MCP-1), and CD68 in the venous tissues. The expression levels of P2Y12, TGFβ1, and MCP-1 were quantified using quantitative reverse transcription–polymerase chain reaction and western blot analyses. Double and triple immunofluorescence staining was performed to precisely localize the cellular localization of P2Y12 expression.Results Expression levels of P2Y12, TGFβ1, MCP-1, and CD68 were significantly higher in stenotic AVF venous tissues than in the control group tissues. Double and triple immunofluorescence staining of stenotic AVF venous tissues indicated that P2Y12 was predominantly expressed in α-SMA-positive vascular smooth muscle cells (VSMCs) and, to a lesser extent, in CD68-positive macrophages, with limited expression in CD31-positive endothelial cells. Moreover, a subset of macrophage-like VSMCs expressing P2Y12 were observed in both stenotic AVF venous tissues and control venous tissues. Additionally, a higher number of P2Y12+/TGF-β1+ double-positive cells were identified in stenotic AVF venous tissues than in the control group tissues.Conclusion Increased expression of P2Y12 in stenotic AVF venous tissues of patients with ESRD suggests its potential involvement in the pathogenesis of venous stenosis within AVFs.

Pharmacological inhibition of the platelet ADP-receptor P2Y12 is a cornerstone in the prevention of atherothrombotic events in adult patients with acute coronary syndrome (ACS). Thienopyridines such as clopidogrel and prasugrel exert their antithrombotic effect by means of active metabolites that irreversibly inhibit P2Y12. Due to the short half-life of these metabolites, a subpopulation of ADP-responsive platelets will form in between dosing. With increased platelet turnover rate or poor patient compliance, the fraction of ADP-responsive platelets will increase, potentially increasing the risk for new thrombotic events. In contrast, the reversible P2Y12 inhibition produced by direct-acting ADP blockers such as ticagrelor and cangrelor inhibit the entire platelet population. In this study, we evaluated the impact of these pharmacological differences on thrombus formation in an ex vivo flow chamber model. A customized image analysis pipeline was used for automatized, large-scale identification and tracking of single platelets incorporated into the thrombus, enabling quantitative analysis of the relative contribution of inhibited and uninhibited platelets to thrombus growth and consolidation. Comparative experiments were conducted using the irreversible and reversible P2Y12 inhibitors prasugrel active metabolite (PAM) and ticagrelor, respectively. Our results show that PAM inhibited thrombus platelet recruitment more gradually than ticagrelor, with a slower onset of inhibition. Further, we show that the presence of a small fraction (

Abstract Background Tau protein forms neurofibrillary tangles and becomes deposited in the brain during Alzheimer’s disease (AD). Tau oligomers are the most reactive species, mediating neurotoxic and inflammatory activity. Microglia are the immune cells in the central nervous system, sense the extracellular Tau via various cell surface receptors. Purinergic P2Y12 receptor can directly interact with Tau oligomers and mediates microglial chemotaxis via actin remodeling. The disease-associated microglia are associated with impaired migration and express a reduced level of P2Y12, but elevate the level of reactive oxygen species and pro-inflammatory cytokines. Results Here, we studied the formation and organization of various actin microstructures such as-podosome, filopodia and uropod in colocalization with actin nucleator protein Arp2 and scaffold protein TKS5 in Tau-induced microglia by fluorescence microscopy. Further, the relevance of P2Y12 signaling either by activation or blockage was studied in terms of actin structure formations and Tau deposits degradation by N9 microglia. Extracellular Tau oligomers facilitate the microglial migration via Arp2-associated podosome and filopodia formation through the involvement of P2Y12 signaling. Similarly, Tau oligomers induce the TKS5-associated podosome clustering in microglial lamella in a time-dependent manner. Moreover, the P2Y12 was evidenced to localize with F-actin-rich podosome and filopodia during Tau-deposit degradation. The blockage of P2Y12 signaling resulted in decreased microglial migration and Tau-deposit degradation. Conclusions The P2Y12 signaling mediate the formation of migratory actin structures like- podosome and filopodia to exhibit chemotaxis and degrade Tau deposit. These beneficial roles of P2Y12 in microglial chemotaxis, actin network remodeling and Tau clearance can be intervened as a therapeutic target in AD.

Rakhmad Hidayat,1– 3 Al Rasyid,2,3 Salim Harris,2,3 Alida Harahap,2 Herqutanto,2 Melva Louisa,2 Erlin Listiyaningsih,4 Aldy Safruddin Rambe,5 Tonny Loho6 1Doctoral Program in Medical Sciences Faculty of Medicine Universitas Indonesia, Jakarta, Indonesia; 2Faculty of Medicine Universitas Indonesia, Jakarta, Indonesia; 3Dr. Cipto Mangunkusumo Hospital, Jakarta, Indonesia; 4Harapan Kita Hospital, Jakarta, Indonesia; 5Sumatera Utara University, Medan, Indonesia; 6Faculty of Medicine and Health Science, Kristen Krida Wacana University, Jakarta, IndonesiaCorrespondence: Rakhmad Hidayat, Tel +62 813 88756299, Email rhidayat.md@gmail.comBackground: Stroke is one of the highest causes of disability and mortality in several countries worldwide. Secondary prevention is important in the management of stroke. Clopidogrel is widely used in Asia as secondary prevention for ischemic stroke, even though several studies in Western show limited data related to clopidogrel resistance in Asia. This study aims to determine the correlation between P2Y12 genetic polymorphism and clopidogrel resistance in Indonesia.Methods: This study was conducted on one-year duration, the subjects were chosen through the consecutive sampling method, all subjects were examined for genetics and resistance to clopidogrel. The data were analyzed through statistical analysis, a bivariate analysis was conducted to determine the correlation between several variables and the resistance variable. This study employed resistance diagnostic methods with VerifyNow. Polymorphism of receptor P2Y12 was tested with the Polymerase Chain Reaction method (PCR) and analysis of restriction fragment length polymorphism (RFLP). The genes tested in this study were G52T and C34T.Results: The number of participants in this study was 112. Examination of gene P2Y12 showed that the majority was homozygote, wild-type C34T allele (67%), and G52T (66.1%). There was no significant correlation between clopidogrel resistance and gene G52T and C34T of P2Y12 (p > 0.05). Hb levels significantly correlated with P2Y12 G52T (p = 0.024). Meanwhile, Fatty Liver significantly correlated with P2Y12 C34T (p = 0.037).Conclusion: Indonesia showed a low clopidogrel resistance rate and a very low C34T and G52T allele P2Y12 gene mutation, meaning that Indonesia had low mutations in the P2Y12. This is the cause of clopidogrel resistance in this study only 15%. Therefore, in a region with less clopidogrel resistance, examination of the P2Y12 gene would not give significant results.Keywords: clopidogrel resistance, P2Y12, stroke, antiplatelet

Abstract Backgrounds Remarkable interindividual variability in clopidogrel response is observed, genetic polymorphisms in P2RY12 and its signal pathway is supposed to affect clopidogrel response in CHD patients. Methods 539 CHD patients treated with clopidogrel were recruited. The platelet reaction index (PRI) indicated by VASP-P level were detected in 12–24 h after clopidogrel loading dose or within 5–7 days after initiation of maintain dose clopidogrel. A total of 13 SNPs in relevant genes were genotyped in sample A (239 CHD patients). The SNPs which have significant differences in PRI will be validated in another sample (sample B, 300 CHD patients). Results CYP2C19*2 increased the risk of clopidogrel resistance significantly. When CYP2C19*2 and CYP2C19*3 were considered, CYP2C19 loss of function (LOF) alleles were associated with more obviously increased the risk of clopidogrel resistance; P2RY12 rs6809699C > A polymorphism was also associated with increased risk of clopidogrel resistance (AA vs CC: P = 0.0398). This difference still existed after stratification by CYP2C19 genotypes. It was also validated in sample B. The association was also still significant even in the case of stratification by CYP2C19 genotypes in all patients (sample A + B). Conclusion Our data suggest that P2RY12 rs6809699 is associated with clopidogrel resistance in CHD patients. Meanwhile, the rs6809699 AA genotype can increase on-treatment platelet activity independent of CYP2C19 LOF polymorphisms.

Background: Tau protein forms neurofibrillary tangles and becomes deposited in the brain during Alzheimer's disease (AD). Tau oligomers are the most reactive species, mediating neurotoxic and inflammatory activity. Microglia are the immune cells in the central nervous system, sense the extracellular Tau via various cell surface receptors. Purinergic P2Y12 receptor can directly interact with Tau oligomers and mediates microglial chemotaxis via actin remodeling. The disease-associated microglia are associated with impaired migration and express a reduced level of P2Y12, but elevate the level of reactive oxygen species and pro-inflammatory cytokines. Results: Here, we studied the formation and organization of various actin microstructures such as-podosome, filopodia and uropod in colocalization with actin nucleator protein Arp2 and scaffold protein TKS5 in Tau-induced microglia by fluorescence microscopy. Further, the relevance of P2Y12 signaling either by activation or blockage was studied in terms of actin structure formations and Tau deposits degradation by N9 microglia. Extracellular Tau oligomers facilitate the microglial migration via Arp2-associated podosome and filopodia formation through the involvement of P2Y12 signaling. Similarly, Tau oligomers induce the TKS5-associated podosome clustering in microglial lamella in a time-dependent manner. Moreover, the P2Y12 was evidenced to localize with F-actin-rich podosome and filopodia during Tau-deposit degradation. The blockage of P2Y12 signaling resulted in decreased microglial migration and Tau-deposit degradation. Conclusions: The P2Y12 signaling mediate the formation of migratory actin structures like- podosome and filopodia to exhibit chemotaxis and degrade Tau deposit. These beneficial roles of P2Y12 in microglial chemotaxis, actin network remodeling and Tau clearance can be intervened as a therapeutic target in AD. [ABSTRACT FROM AUTHOR]

The P2Y12 receptor is an important member of the purinergic receptor family, known for its critical role in platelet activation and thrombosis. In our previously published study, the acridinone analogue NSC618159 was identified as a potent antagonist of P2Y12. In this work, we investigate the conformational changes in P2Y12 when bound to NSC618159 using molecular dynamics simulations on the receptor's active and inactive forms (4PXZ and 4NTJ, respectively). It was observed that it took the systems about 7 ns and 12 ns to stabilise when NSC618159 was in complex with the active and inactive forms of P2Y12, respectively. Additionally, the binding pocket of the crystal structure 4PXZ expanded from 172.34 Å3 to an average of 661.55 Å3 when bound to NSC618159, with a maximum pocket volume of 820.49 Å3. This expansion was attributed to the pulled away transmembrane (TM) helices and the adoption of a more open conformation by extracellular loop 2 (EL2). In contrast, 4NTJ's pocket volume was mostly consistent and had an average of 1203.82 Å3. Moreover, the RMSF profile of the NSC618159-4PXZ complex showed that residues of TM-I and TM-VII had similar fluctuations to the 4NTJ crystal structure, representing the inactive form of P2Y12. Finally, the energy components and binding affinities of NSC618159 towards the active and inactive forms of P2Y12 were predicted using the MM-PBSA approach. According to the results, the binding affinity of NSC618159 towards both active (4PXZ) and inactive (4NTJ) forms of P2Y12 was found to be almost identical, with values of −43.52 and −41.68 kcal/mol, respectively. In conclusion, our findings provide new insights into the conformational changes of P2Y12 upon binding to NSC618159 and may have implications for the development of new P2Y12 antagonists with enhanced potency and specificity. [ABSTRACT FROM AUTHOR]

People living with HIV (PLWHIV) present an increased risk of adverse cardiovascular events. We aimed to assess whether antiretroviral therapy (ART) pharmacologically enhances platelet reactivity and platelet activation intensity, and explore the potential association with underlying inflammatory status. This was a cross-sectional cohort study carried out among PLWHIV on diverse ART regimens. Platelet reactivity and activation intensity were assessed using the bedside point-of-care VerifyNow assay, in P2Y12 reaction units (PRU), measurements of monocyte-platelet complexes, and P-selectin and GPIIb/IIIa expression increase, following activation with ADP, respectively. Levels of major inflammatory markers and whole blood parameters were also evaluated. In total, 71 PLWHIV, 59 on ART and 22 healthy controls, were included in this study. PRU values were significantly elevated in PLWHIV compared to controls [Mean; 257.85 vs. 196.67, p < 0.0001], but no significant differences were noted between ART-naïve or ART-experienced PLWHIV, or between TAF/TDF and ABC based regimens, similar to systemic inflammatory response. However, within-group analysis showed that PRUs were significantly higher in ABC/PI vs ABC/INSTI or TAF/TDF + PI patients, in line with levels of IL-2. PRU values did not correlate strongly with CD4 counts, viral load, or cytokine values. P-selectin and GPIIb/IIIa expression increased following ADP activation and were significantly more prominent in PLWHIV (p < 0.005). Platelet reactivity and platelet activation intensity were shown to be increased in PLWHIV, but they did not appear to be related to ART initiation, similar to the underlying systemic inflammatory response. [ABSTRACT FROM AUTHOR]

Not required

BackgroundDual antiplatelet therapy (DAT), most commonly with aspirin and Clopidogrel, is the standard of care for intracranial stenting, including flow diversion. Clopidogrel response varies by individual.ObjectiveTo investigate the real-world precision of VerifyNow P2Y12 assessment (Accumetrics, San Diego, California) of Clopidogrel response.MethodsUsing a prospectively-collected, IRB-approved cerebral aneurysm database 643 patients were identified who were treated with the Pipeline embolization device from 2011 to 2017. Patients with multiple P2Y12 assays drawn within a 24-h window were identified. A single patient could contribute multiple, independent sets. Levels drawn before a 5-d course of DAT and patients who received alternative antiplatelet agents were excluded. Therapeutic range was defined as platelet reaction units (PRU) 60-200.ResultsA total of 1586 P2Y12 measurements were recorded; 293 (46%) patients had more than one assay. One hundred forty (22%) patients had multiple P2Y12 measurements within 24 h. These patients accounted for 230 independent 24-h sets. The average P2Y12 fluctuation across all sets was 35 points; the 25th, 50th, and 75th percentiles were 12, 26, and 48 points, respectively. Of the 230 24-h sets of P2Y12 assays, 76% remained within their original therapeutic category: 100 (43%) all therapeutic, 54 (23%) all hypo-responsive, and 21 (9%) all hyper-responsive. Twenty-four percent of patients fluctuated between therapeutic categories when multiple P2Y12 assessments were drawn within a 24-h period: 29 (13%) between hypo-response and therapeutic, 23 (10%) between hyper-response and therapeutic, and 3 (1%) between hypo-response and hyper-response.ConclusionOur experience suggests P2Y12 is an often-imprecise measure, and this should be considered when utilizing P2Y12 levels for clinical decisions.

Clopidogrel combined with aspirin is widely used in coronary artery disease (CAD) patients, while some patients exhibit high platelet activity when receiving the combined treatment. Current environmental and genetic factors could only explain part of the variability in clopidogrel efficacy. Human platelets harbor abundant miRNAs which might affect clopidogrel efficacy by regulating the expression of key proteins in the clopidogrel antiplatelet signaling pathway. This study aimed to investigate the association between platelet miRNA levels and clopidogrel efficacy. Here we recruited 508 CAD patients who underwent clopidogrel antiplatelet therapy and determined the platelet reactivity index (PRI) to evaluate antiplatelet reactivity responses to clopidogrel. Subsequently, 22 patients with extreme clopidogrel response were selected for platelet small RNA sequencing. Another 41 CAD patients taking clopidogrel were collected to verify the differentially expressed candidate miRNAs. We found the metabolic types of the CYP2C19 enzyme (based on CYP2C19 * 2 and * 3 polymorphisms) could significantly affect the PRI of CAD patients with or without percutaneous coronary intervention (PCI) in Chinese. A total of 43 miRNAs were differentially expressed in the platelets from the 22 extreme clopidogrel response samples, and 109 miRNAs were differentially expressed in the 13 CYP2C19 extensive metabolizers with extreme clopidogrel response. Platelet miR-199a-5p levels were correlated negatively with PRI after clopidogrel therapy. Studies in cultured cells revealed that miR-199a-5p inhibited the expression of VASP, a key effector protein downstream of the P2Y12 receptor. In conclusion, we found the expression of VASP could be inhibited by miR-199a-5p, and decreased platelet miR-199a-5p was associated with high on-clopidogrel platelet reactivity in CAD patients. What is the context? ● Clopidogrel combined with aspirin is widely used in coronary artery disease (CAD) patients, while some patients exhibit high platelet activity when receiving the combined treatment. ● Current environmental and genetic factors could only explain part of the variability in clopidogrel efficacy. ● Human platelets harbor abundant miRNAs which might affect clopidogrel efficacy by regulating the expression of key proteins in the clopidogrel antiplatelet signaling pathway. What is new? ● We found that decreased platelet miR-199a-5p level was associated with high on-clopidogrel platelet reactivity. ● Overexpression of miR-199a-5p significantly down-regulated the expression of VASP protein in cultured cells. What is the impact? ● The current study provided new insights into the exploration of interindividual variability in clopidogrel response from the perspective of miR-199a-5p and VASP interaction. [ABSTRACT FROM AUTHOR]

OBJECTIVE Systemic-to-pulmonary artery shunts are amongst the most common palliative procedures performed in neonates with congenital heart defects. These procedures require immediate postoperative thromboprophylaxis to prevent life-threatening shunt thrombosis. The novel use of intravenous P2Y12 platelet receptor antagonists has led to a need for dosing recommendations and monitoring. This study aims to determine cangrelor dosing in neonates through laboratory assessment of P2Y12 receptor reactivity and adverse events. METHODS Observational retrospective cohort study on the use of cangrelor for thromboprophylaxis in the immediate postoperative period of neonates undergoing placement of systemic-to-pulmonary artery shunts in a tertiary children's hospital from March 2020 to March 2021. RESULTS Ten neonates receiving cangrelor post systemic-to-pulmonary artery shunt placement were included in the study. Median age and weight were 4 days (IQR, 2.75-5.25) and 3.49 kg (IQR, 3.1-3.75), respectively. Five (50%) patients received a 3.5-mm shunt, while the remaining patients received a 4-mm shunt. For thrombin inhibition, 5 (50%) patients received heparin and 5 (50%) received bivalirudin. Median cangrelor dose was 0.1 mcg/kg/min (IQR, 0.1-0.1). Median achieved P2Y12 reaction units (PRU) at this cangrelor dose was 127.5 (IQR, 72.5-173.75). No shunt thrombosis occurred in these patients; however, there was 1 minor hemorrhagic event. CONCLUSIONS Our study suggests that a cangrelor dose of 0.1 mcg/kg/min is associated with therapeutic PRU and prevents shunt thrombosis in neonates post systemic-to-pulmonary artery shunt, with minimal hemorrhagic complications. ABBREVIATIONS ADP, adenosine diphosphate; CICU, cardiac intensive care unit; ECMO, extracorporeal membrane oxygenation; FFP, fresh frozen plasma; HLHS, hypoplastic left heart syndrome; IQR, interquartile range; PRBC, packed red blood cells; PRU, P2Y12 reaction units; PTT, partial thromboplastin time; S-PA, systemic-to-pulmonary artery; VAD, ventricular assist device [ABSTRACT FROM AUTHOR]

Abstract Background High on-treatment platelet reactivity (HTPR) remains a major problem in the acute management of ST-elevation myocardial infarction (STEMI), leading to higher rates of stent thrombosis and mortality. We aimed to investigate a novel, prehospital treatment strategy using cangrelor and tested its pharmacodynamic effects in a model using healthy volunteers. Methods We conducted a dose-finding, open-label, pilot trial including 12 healthy volunteers and tested three ascending bolus infusions of cangrelor (5 mg, 10 mg and 20 mg) and a bolus infusion followed by a continuous infusion via an intravenous (IV) flow regulator. Platelet function was assessed using multiple electrode aggregometry (MEA), vasodilator-stimulated phosphoprotein phosphorylation assay (VASP-P) and the platelet function analyzer. In an ex vivo experiment, epinephrine was used to counteract the antiplatelet effect of cangrelor. Results All cangrelor bolus infusions resulted in immediate and pronounced platelet inhibition. Bolus infusions of cangrelor 20 mg resulted in sufficient platelet inhibition assessed by MEA for 20 min in 90% of subjects. Infusion of cangrelor via the IV flow regulator resulted in sufficient platelet inhibition throughout the course of administration. Ex vivo epinephrine, in concentrations of 200 and 500 ng/mL was able to partially reverse the antiplatelet effect of cangrelor in a dose-dependent manner. Conclusions Weight-adapted bolus infusions followed by a continuous infusion of cangrelor via IV flow regulator result in immediate and pronounced platelet inhibition in healthy subjects. Cangrelor given as weight-adapted bolus infusion followed by a continuous infusion using an IV flow regulator may be a viable treatment approach for effective and well controllable prehospital platelet inhibition. Trial registration EC (Medical University of Vienna) 1835/2019 and EudraCT 2019-002792-34 .

Ischemic events are associated with severe inflammation and are here referred to as ischemic inflammatory response (IIR). Recent studies identified the formation of platelet–neutrophil complexes (PNC) as key players in IIR. We investigated the role of extracellular platelet nucleotide signaling in the context of IIR and defined a cybernetic circle, including description of feedback loops. Cybernetic circles seek to integrate different levels of information to understand how biological systems function. Our study specifies the components of the cybernetic system of platelets in IIR and describes the theoretical progression of IIR passing the cybernetic cycle with positive and negative feedback loops based on nucleotide-dependent signaling and functional regulation. The cybernetic components and feedback loops were explored by cytometry, immunohistological staining, functional blocking antibodies, and ADP/ATP measurements. Using several ex vivo and in vivo approaches we confirmed cybernetic parameters, such as controller, sensor, and effector (VASP phosphorylation, P2Y12, ADORAs and GPIIb/IIIa activity), as well as set points (ADP, adenosine) and interfering control and disturbance variables (ischemia). We demonstrate the impact of the regulated platelet–neutrophil complex (PNC) formation in blood and the resulting damage to the affected inflamed tissue. Taken together, extracellular nucleotide signaling, PNC formation, and tissue damage in IIR can be integrated in a controlled cybernetic circle of platelet function, as introduced through this study. [ABSTRACT FROM AUTHOR]

Clopidogrel is a widely prescribed prodrug with anti-thrombotic activity through irreversible inhibition of the P2Y12 receptor on platelets. It is FDA-approved for the clinical management of thrombotic diseases like unstable angina, myocardial infarction, stroke, and during percutaneous coronary interventions. Hepatic clopidogrel metabolism generates several distinct metabolites. Only one of these metabolites is responsible for inhibiting the platelet P2Y12 receptor. Importantly, various non-hemostatic effects of clopidogrel therapy have been described. These non-hemostatic effects are perhaps unsurprising, as P2Y12 receptor expression has been reported in multiple tissues, including osteoblasts, leukocytes, as well as vascular endothelium and smooth muscle. While the "inactive" metabolites have been commonly thought to be biologically inert, recent findings have uncovered P2Y12 receptor-independent effects of clopidogrel treatment that may be mediated by understudied metabolites. In this review, we summarize both the P2Y12 receptor-mediated and non-P2Y12 receptor-mediated effects of clopidogrel and its metabolites in various tissues. [ABSTRACT FROM AUTHOR]

目的二磷酸腺苷受体P2Y12介导的血小板活化是血小板活化及血栓形成的核心机制，本研究探讨囊性纤维化跨膜转导调节子（CFTR）对P2Y12介导的血小板活化的影响。方法应用8~16周龄CFTR全基因敲除（Cftr-/-）小鼠及野生型（Cftr+/+）小鼠，分别制备胶原蛋白和肾上腺素诱导的肺栓塞小鼠模型。分离Cftr-/-和Cftr+/+小鼠外周血的血小板， 采用免疫印迹技术检测P2Y12、PI3K以及AKT 总蛋白及磷酸化蛋白的表达。采用二磷酸腺苷（ADP）孵育人巨核细胞株Meg-01，检测ADP对CFTR和上述蛋白表达的影响。进一步应用特异性CFTR氯通道抑制剂CFTRinh-172与Meg-01细胞共孵育，检测其对CFTR和上述蛋白表达的影响。结果与Cftr+/+小鼠肺栓塞模型组相比，Cftr-/-鼠肺栓塞组织切片栓塞显著增加。Cftr-/-显著增加小鼠外周血血小板P2Y12、磷酸化PI3K和AKT 蛋白表达。P2Y12全基因敲除小鼠血小板CFTR蛋白表达无明显改变，上述结果提示CFTR负性调控P2Y12维持正常血小板活化功能。Meg-01细胞实验结果表明 ADP浓度依赖性地诱导Meg-01细胞P2Y12蛋白和PI3K以及AKT蛋白磷酸化增高，而CFTR蛋白表达水平逐渐降低。CFTR 特异性阻断剂CFTRinh-172显著诱导Meg-01细胞P2Y12蛋白表达增高。结论本研究揭示了血小板活化的一个新机制，即CFTR通过调控血小板P2Y12蛋白表达影响血小板活化。

Xiao Zhang,1,&ast; Juntao Wang,1,&ast; Aihua Sui,2 Nannan Zhang,1 Qiulan Lv,2 Zhenfang Liu3 1Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, 266000, People’s Republic of China; 2Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, 266000, People’s Republic of China; 3Department of Emergency, The Affiliated Hospital of Qingdao University, Qingdao, 266000, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Zhenfang Liu Email liuzhenfangzf@outlook.comBackground and Objective: Neuropathic pain remains a clinical challenge with limited effective treatments. Previous studies have found that magnolol (Mag), an ingredient existing in some herbs, showed neuroprotective effect. However, it remains unclear whether Mag can alleviate neuropathic pain.Methods: Chronic constriction injury (CCI) is used as the neuropathic pain model. Mice were randomly divided into 5 groups: Sham, CCI, CCI + 5, 10, 30 mg/kg Mag groups. Thermal and mechanical paw withdrawal threshold were performed at baseline and on the 3rd, 5th, 7th, 14th days post-surgery. Lumbar spinal cord and blood samples were collected on the 14th day. Blood lipid profile, kidney and liver functions, as well as the activation of microglia were evaluated, along with the related signal pathway examined using multiple methods including immunohistochemistry, RT-PCR and Western blot.Results: Mag alleviated thermal and mechanical hypersensitivity in CCI mice. CCI activated microglia and upregulated the expression of P2Y12, while Mag inhibited microglial activation, and downregulated the expression of P2Y12. Mag also blocked the activation of p38 mitogen-activated protein kinase (MAPK) and other pain-related cytokines such as IL-6, TNF-α and IL-1β.Conclusion: The findings indicate that Mag has antinociceptive effect on neuropathic pain, probably mediated through P2Y12 receptors and p38 MAPK mediated pathways. With its relatively safe profile, Mag may be a potential therapeutic agent for neuropathic pain.Keywords: magnolol, neuropathic pain, P2Y12, CCI, MAPK, cytokines

The P2Y12 receptor is an important member of the purinergic receptor family, known for its critical role in platelet activation and thrombosis. In our previously published study, the acridinone analogue NSC618159 was identified as a potent antagonist of P2Y12. In this work, we investigate the conformational changes in P2Y12 when bound to NSC618159 using molecular dynamics simulations on the receptor’s active and inactive forms (4PXZ and 4NTJ, respectively). It was observed that it took the systems about 7 ns and 12 ns to stabilise when NSC618159 was in complex with the active and inactive forms of P2Y12, respectively. Additionally, the binding pocket of the crystal structure 4PXZ expanded from 172.34 Å3 to an average of 661.55 Å3 when bound to NSC618159, with a maximum pocket volume of 820.49 Å3. This expansion was attributed to the pulled away transmembrane (TM) helices and the adoption of a more open conformation by extracellular loop 2 (EL2). In contrast, 4NTJ’s pocket volume was mostly consistent and had an average of 1203.82 Å3. Moreover, the RMSF profile of the NSC618159-4PXZ complex showed that residues of TM-I and TM-VII had similar fluctuations to the 4NTJ crystal structure, representing the inactive form of P2Y12. Finally, the energy components and binding affinities of NSC618159 towards the active and inactive forms of P2Y12 were predicted using the MM-PBSA approach. According to the results, the binding affinity of NSC618159 towards both active (4PXZ) and inactive (4NTJ) forms of P2Y12 was found to be almost identical, with values of −43.52 and −41.68 kcal/mol, respectively. In conclusion, our findings provide new insights into the conformational changes of P2Y12 upon binding to NSC618159 and may have implications for the development of new P2Y12 antagonists with enhanced potency and specificity.

People living with HIV (PLWHIV) present an increased risk of adverse cardiovascular events. We aimed to assess whether antiretroviral therapy (ART) pharmacologically enhances platelet reactivity and platelet activation intensity, and explore the potential association with underlying inflammatory status. This was a cross-sectional cohort study carried out among PLWHIV on diverse ART regimens. Platelet reactivity and activation intensity were assessed using the bedside point-of-care VerifyNow assay, in P2Y12 reaction units (PRU), measurements of monocyte-platelet complexes, and P-selectin and GPIIb/IIIa expression increase, following activation with ADP, respectively. Levels of major inflammatory markers and whole blood parameters were also evaluated. In total, 71 PLWHIV, 59 on ART and 22 healthy controls, were included in this study. PRU values were significantly elevated in PLWHIV compared to controls [Mean; 257.85 vs. 196.67, p < 0.0001], but no significant differences were noted between ART-naïve or ART-experienced PLWHIV, or between TAF/TDF and ABC based regimens, similar to systemic inflammatory response. However, within-group analysis showed that PRUs were significantly higher in ABC/PI vs ABC/INSTI or TAF/TDF + PI patients, in line with levels of IL-2. PRU values did not correlate strongly with CD4 counts, viral load, or cytokine values. P-selectin and GPIIb/IIIa expression increased following ADP activation and were significantly more prominent in PLWHIV (p < 0.005). Platelet reactivity and platelet activation intensity were shown to be increased in PLWHIV, but they did not appear to be related to ART initiation, similar to the underlying systemic inflammatory response.

Simple Summary: Acute Coronary Syndrome is a disease of the circulatory system characterized by the partial or complete blockage of coronary arteries. In thrombosis, a major role is played by platelets—the smallest, anucleate, morphotic elements in the bloodstream. Platelets are involved in the process of hemostasis, which ensures the continuity of the blood vessel by forming a clot that prevents blood loss. Unique structures of blood platelets ensure their high reactivity in the vascular microenvironment due to the interaction with many biologically active molecules, which is recognized by the surface receptors. The research carried out in the manuscript is aimed at detecting potential changes at the molecular level in platelet surface receptors that could constitute the potential importance of the occurrence of Acute Coronary Syndrome. The obtained results indicate that the P2Y12 receptor, which is the main target of antiplatelet therapy, is expressed more frequently among patients. In addition, we have shown that at the genetic level, quantitative changes also occur in the case of other receptors that are important in the activation of platelets. The following manuscript suggests the potential mechanisms responsible for the differences between patients and healthy donors due to a better understanding of the molecular causes of Acute Coronary Syndrome pathogenesis. The pathological conditions caused by blood platelet activation constitute a fundamental core in the pathogenesis of Acute Coronary Syndrome (ACS). The hyperactivity of platelets in ACS is well-documented, but there is still little research into the molecular basis of phenotypic changes in platelet functionality. To expand the knowledge of this phenomenon, we analyzed the disturbances in the expression of several key platelet receptors and the aspect of regulating potential abnormalities. Platelet surface receptors are responsible for maintaining the hemostatic balance, platelet interaction with immune cells, and support of the coagulation cascade leading to occlusion of the vessel lumen. Due to their prominent role, platelet receptors constitute a major target in pharmacological treatment. Our work aimed to identify the molecular alteration of platelet surface receptors, which showed augmented mRNA expression of P2Y12, GP1BB, ITGA2B, and ITGB3 and increased protein concentrations of P2Y12 and GP IIb/IIIa in ACS. The upregulation of the P2Y12 level was also confirmed by confocal and cytometric visualization. Furthermore, we evaluated the expression of two microRNAs: miR-223-3p and miR-126-3p, which were suggested to regulate platelet P2Y12 expression. Results of our study present new insight into the molecular background of ACS. [ABSTRACT FROM AUTHOR]

Background: High on-treatment platelet reactivity (HTPR) remains a major problem in the acute management of ST-elevation myocardial infarction (STEMI), leading to higher rates of stent thrombosis and mortality. We aimed to investigate a novel, prehospital treatment strategy using cangrelor and tested its pharmacodynamic effects in a model using healthy volunteers. Methods: We conducted a dose-finding, open-label, pilot trial including 12 healthy volunteers and tested three ascending bolus infusions of cangrelor (5 mg, 10 mg and 20 mg) and a bolus infusion followed by a continuous infusion via an intravenous (IV) flow regulator. Platelet function was assessed using multiple electrode aggregometry (MEA), vasodilator-stimulated phosphoprotein phosphorylation assay (VASP-P) and the platelet function analyzer. In an ex vivo experiment, epinephrine was used to counteract the antiplatelet effect of cangrelor. Results: All cangrelor bolus infusions resulted in immediate and pronounced platelet inhibition. Bolus infusions of cangrelor 20 mg resulted in sufficient platelet inhibition assessed by MEA for 20 min in 90% of subjects. Infusion of cangrelor via the IV flow regulator resulted in sufficient platelet inhibition throughout the course of administration. Ex vivo epinephrine, in concentrations of 200 and 500 ng/mL was able to partially reverse the antiplatelet effect of cangrelor in a dose-dependent manner. Conclusions: Weight-adapted bolus infusions followed by a continuous infusion of cangrelor via IV flow regulator result in immediate and pronounced platelet inhibition in healthy subjects. Cangrelor given as weight-adapted bolus infusion followed by a continuous infusion using an IV flow regulator may be a viable treatment approach for effective and well controllable prehospital platelet inhibition. Trial registration: EC (Medical University of Vienna) 1835/2019 and EudraCT 2019-002792-34. [ABSTRACT FROM AUTHOR]

Platelets are at the forefront of human health and disease following the advances in their research presented in past decades. Platelet activation, their most crucial function, although beneficial in the case of vascular injury, may represent the initial step for thrombotic complications characterizing various pathologic states, primarily atherosclerotic cardiovascular diseases. In this review, we initially summarize the structural and functional characteristics of platelets. Next, we focus on the process of platelet activation and its associated factors, indicating the potential molecular mechanisms involving inflammation, endothelial dysfunction, and miRs. Finally, an overview of the available antiplatelet agents is being portrayed, together with agents possessing off-set platelet-inhibitory actions, while an extensive presentation of drugs under investigation is being given. [ABSTRACT FROM AUTHOR]

The pharmacodynamics of the purinergic receptor type Y, subtype 12 (P2Y12) inhibitors has evolved. Our understanding of the metabolism of P2Y12 inhibitors has revealed polymorphisms that impact drug metabolism and antiplatelet efficacy, leading to genetic testing guided therapy. In addition, assays of platelet function and biochemistry have provided insight into our understanding of the efficacy of “antiplatelet” therapy, identifying patients with high or low platelet reactivity on P2Y12 therapy. Despite the data, the implementation of these testing modalities has not gained mainstream adoption across hospital systems. Given differences in potency between the three clinically available P2Y12 inhibitors, the balance between thrombotic and bleeding complications must be carefully considered, especially for the large proportion of patients at higher risk for bleeding. Here we review the current data for genetic and functional testing, risk assessment strategies, and guidelines for P2Y12 inhibitors guided therapy.

The principal demonstrated role of the nonvisual arrestins in vivo is to limit G protein-coupled receptor (GPCR) signaling. Nonetheless, a direct demonstration of this fundamental ability in platelets remains lacking, despite the prominent role played by GPCRs in platelet activation. This paper describes the basic characterization of the activatory responses of platelets from mice lacking arrestin-3 (arr3-/-), revealing pleiotropic roles dependent on GPCR ligand. Functionally, arrestin-3 acts as a brake on platelet aggregation regardless of ligand tested. Downstream of P2Y receptors, arr3-/- mice show increased secretion and integrin activation mirrored by enhanced intracellular calcium signaling and global PKC-dependent phosphorylation. Furthermore, P2Y12 receptor (P2Y12R) activity as assessed by ADP-mediated reduction of VASP phosphorylation is enhanced in arr3-/-mice. Downstream of PAR receptors there are similar increases in secretion and integrin activation in arr3-/- mice, together with enhanced PKC activity. Last, in arr3-/- mice the TP receptor displays unaltered PKC activity but markedly reduced calcium responses, which together with the kinetics of the aggregation response suggested a unique positive regulatory role for arrestin-3 in TP signaling. Overall, this paper reveals pleiotropic roles for arrestin-3 dependent on GPCR ligand describing for the first time a negative regulatory function for arrestin-3 in platelets.

Background: Patients with atrial fibrillation and severe chronic kidney disease have higher risks of bleeding, thromboembolism, and mortality. However, optimal anticoagulant choice in these high-risk patients remains unclear., Methods and Results: Using deidentified electronic health records from the Optum Labs Data Warehouse, adults with atrial fibrillation and severe chronic kidney disease (estimated glomerular filtration rate <30 mL/min per 1.73 m 2 ) initiating warfarin, apixaban, or rivaroxaban between 2011 and 2021 were included. Using inverse probability of treatment weighting, adjusted risks of major bleeding, stroke/systemic embolism, and death were compared among agents. A total of 6794 patients were included (mean age, 78.5 years; mean estimated glomerular filtration rate, 24.7 mL/min per 1.73 m 2 ; 51% women). Apixaban versus warfarin was associated with a lower risk of major bleeding (incidence rate, 1.5 versus 2.9 per 100 person-years; subdistribution hazard ratio [sub-HR], 0.53 [95% CI, 0.39-0.70]), and similar risks for stroke/systemic embolism (incidence rate, 1.9 versus 2.4 per 100 person-years; sub-HR, 0.80 [95% CI, 0.59-1.09]) and death (incidence rate, 4.6 versus 4.5 per 100 person-years; HR, 1.03 [95% CI, 0.82-1.29]). Rivaroxaban versus warfarin was associated with a higher risk of major bleeding (incidence rate, 4.9 versus 2.9 per 100 person-years; sub-HR, 1.65 [95% CI, 1.10-2.48]), with no difference in risks for stroke/systemic embolism and death. Apixaban versus rivaroxaban was associated with a lower risk of major bleeding (sub-HR, 0.53 [95% CI, 0.36-0.78])., Conclusions: These real-world findings are consistent with potential safety advantages of apixaban over warfarin and rivaroxaban for patients with atrial fibrillation and severe chronic kidney disease. Further randomized trials comparing individual oral anticoagulants are warranted.

Background Dual antiplatelet therapy based on aspirin and P2Y12 receptor antagonists such as clopidogrel is currently the primary treatment for coronary artery disease (CAD). However, a percentage of patients exhibit clopidogrel resistance, in which genetic factors play vital roles. This study aimed to investigate the roles of GAS5 (growth arrest‐specific 5) and its rs55829688 polymorphism in clopidogrel response in patients with CAD. Methods and Results A total of 444 patients with CAD receiving dual antiplatelet therapy from 2017 to 2018 were enrolled to evaluate the effect of GAS5 single nucleotide polymorphism rs55829688 on platelet reactivity index. Platelets from 37 patients of these patients were purified with microbeads to detect GAS5 and microRNA‐223‐3p (miR‐223‐3p) expression. Platelet‐rich plasma was isolated from another 17 healthy volunteers and 46 newly diagnosed patients with CAD to detect GAS5 and miR‐223‐3p expression. A dual‐luciferase reporter assay was performed to explore the interaction between miR‐223‐3p and GAS5 or P2Y12 3′‐UTR in (human embryonic kidney 293 cell line that expresses a mutant version of the SV40 large T antigen) HEK 293T and (megakaryoblastic cell line derived in 1983 from the bone marrow of a chronic myeloid leukemia patient with megakaryoblastic crisis) MEG‐01 cells. Loss‐of‐function and gain‐of‐function experiments were performed to reveal the regulation of GAS5 toward P2Y12 via miR‐223‐3p in MEG‐01 cells. We observed that rs55829688 CC homozygotes showed significantly decreased platelet reactivity index than TT homozygotes in CYP2C19 poor metabolizers. Platelet GAS5 expression correlated positively with both platelet reactivity index and P2Y12 mRNA expressions, whereas platelet miR‐223‐3p expression negatively correlated with platelet reactivity index. Meanwhile, a negative correlation between GAS5 and miR‐223‐3p expressions was observed in platelets. MiR‐223‐3p mimic reduced while the miR‐223‐3p inhibitor increased the expression of GAS5 and P2Y12 in MEG‐01 cells. Knockdown of GAS5 by siRNA increased miR‐223‐3p expression and decreased P2Y12 expression, which could be reversed by the miR‐223‐3p inhibitor. Meanwhile, overexpression of GAS5 reduced miR‐223‐3p expression and increased P2Y12 expression, which could be reversed by miR‐223‐3p mimic. Conclusions GAS5 rs55829688 polymorphism might affect clopidogrel response in patients with CAD with the CYP2C19 poor metabolizer genotypes, and GAS5 regulates P2Y12 expression and clopidogrel response by acting as a competitive endogenous RNA for miR‐223‐3p.

Abstract Viral encephalitis is still very prominent around the world, and traditional antiviral therapies still have shortcomings. Some patients cannot get effective relief or suffer from serious sequelae. At present, people are studying the role of the innate immune system in viral encephalitis. Microglia, as resident cells of the central nervous system (CNS), can respond quickly to various CNS injuries including trauma, ischemia, and infection and maintain the homeostasis of CNS, but this response is not always good; sometimes, it will exacerbate damage. Studies have shown that microglia also act as a double-edged sword during viral encephalitis. On the one hand, microglia can sense ATP signals through the purinergic receptor P2Y12 and are recruited around infected neurons to exert phagocytic activity. Microglia can exert a direct antiviral effect by producing type 1 interferon (IFN-1) to induce IFN-stimulated gene (ISG) expression of themselves or indirect antiviral effects by IFN-1 acting on other cells to activate corresponding signaling pathways. In addition, microglia can also exert an antiviral effect by inducing autophagy or secreting cytokines. On the other hand, microglia mediate presynaptic membrane damage in the hippocampus through complement, resulting in long-term memory impairment and cognitive dysfunction in patients with encephalitis. Microglia mediate fetal congenital malformations caused by Zika virus (ZIKV) infection. The gene expression profile of microglia in HIV encephalitis changes, and they tend to be a pro-inflammatory type. Microglia inhibited neuronal autophagy and aggravated the damage of CNS in HIV encephalitis; E3 ubiquitin ligase Pellino (pelia) expressed by microglia promotes the replication of virus in neurons. The interaction between amyloid-β peptide (Aβ) produced by neurons and activated microglia during viral infection is uncertain. Although neurons can mediate antiviral effects by activating receptor-interacting protein kinases 3 (RIPK3) in a death-independent pathway, the RIPK3 pathway of microglia is unknown. Different brain regions have different susceptibility to viruses, and the gene expression of microglia in different brain regions is specific. The relationship between the two needs to be further confirmed. How to properly regulate the function of microglia and make it exert more anti-inflammatory effects is our next research direction.

Background. Myocardial ischemia-reperfusion (I/R) injury is still thought to be an unsolved puzzle that may lead to reperfusion arrhythmias and sudden cardiac death. Inflammation plays a key role in myocardial I/R. Studies have indicated that purinoceptor 2Y12 (P2Y12) antagonists have anti-inflammatory properties that are cardioprotective. Objectives. In this study, we explored whether inhibition of P2Y12 in macrophages could reduce cardiac inflammation and attenuate reperfusion arrhythmias after myocardial I/R. Materials and methods. Rats were randomly divided into 4 groups: group A (control + vehicle); group B (control + P2Y12 shRNA lentiviral vector); group C (myocardial I/R + vehicle); and group D (myocardial I/R + P2Y12 shRNA lentiviral vector). Infarct size, reperfusion arrhythmias, and P2Y12 and platelet endothelial cell adhesion molecule-1 (CD31) protein expression were measured. Results. The incidence of reperfusion ventricular tachycardia and fibrillation (VT/VF) was 90% in the I/R group, while it was reduced to 50% by P2Y12 shRNA treatment. Ionized calcium binding adapter molecule 1 and P2Y12 immunoreactivity in the myocardial I/R + P2Y12 shRNA group was lower compared to the myocardial I/R group. P2Y12 shRNA treatment increased α-smooth muscle actin (α-SMA) and CD31 protein expression, as evidence by western blot and immunohistochemistry analyses (0.31 ±0.01 compared to 0.26 ±0.008, group D compared to group C, p < 0.05). Conclusions. Inhibition of P2Y12 in macrophages improved reperfusion arrhythmias in our rat I/R model, suggesting that blocking P2Y12 could decrease the inflammatory response after cardiac perfusion. [ABSTRACT FROM AUTHOR]

[Display omitted] [ABSTRACT FROM AUTHOR]

The pathological conditions caused by blood platelet activation constitute a fundamental core in the pathogenesis of Acute Coronary Syndrome (ACS). The hyperactivity of platelets in ACS is well-documented, but there is still little research into the molecular basis of phenotypic changes in platelet functionality. To expand the knowledge of this phenomenon, we analyzed the disturbances in the expression of several key platelet receptors and the aspect of regulating potential abnormalities. Platelet surface receptors are responsible for maintaining the hemostatic balance, platelet interaction with immune cells, and support of the coagulation cascade leading to occlusion of the vessel lumen. Due to their prominent role, platelet receptors constitute a major target in pharmacological treatment. Our work aimed to identify the molecular alteration of platelet surface receptors, which showed augmented mRNA expression of P2Y12, GP1BB, ITGA2B, and ITGB3 and increased protein concentrations of P2Y12 and GP IIb/IIIa in ACS. The upregulation of the P2Y12 level was also confirmed by confocal and cytometric visualization. Furthermore, we evaluated the expression of two microRNAs: miR-223-3p and miR-126-3p, which were suggested to regulate platelet P2Y12 expression. Results of our study present new insight into the molecular background of ACS.

Platelets are at the forefront of human health and disease following the advances in their research presented in past decades. Platelet activation, their most crucial function, although beneficial in the case of vascular injury, may represent the initial step for thrombotic complications characterizing various pathologic states, primarily atherosclerotic cardiovascular diseases. In this review, we initially summarize the structural and functional characteristics of platelets. Next, we focus on the process of platelet activation and its associated factors, indicating the potential molecular mechanisms involving inflammation, endothelial dysfunction, and miRs. Finally, an overview of the available antiplatelet agents is being portrayed, together with agents possessing off-set platelet-inhibitory actions, while an extensive presentation of drugs under investigation is being given.

Purpose: To investigate the effect of dexmedetomidine on streptozotocin (STZ)-induced diabetic neuropathy pain (DNP) in rats and elucidate its mechanism of action. Methods: The DNP rat model was established by injecting STZ (70 mg/kg) following dexmedetomidine treatment. Next BV-2 cells were stimulated using lipopolysaccharide (LPS, 200 ng/mL) and then administered 20 μM dexmedetomidine. Blood glucose levels, body weight, and paw withdrawal threshold (PWT) were measured once a week in DNP rats. Transfection was performed, and luciferase reporter assay was used to verify microRNA (miR)-337 binding to Rap1A mRNA. Reverse transcriptionpolymerase chain reaction (RT-PCR) was used to measure the levels of miR-618 and P2Y12 while the protein levels of P2Y12 and ionized calcium-binding adaptor molecule 1 (IBA-1) were determined by western blot analysis. Results: Dexmedetomidine treatment significantly increased PWT (p < 0.01) in DNP rats and decreased miR-618 expression (p < 0.01) but increased P2Y12 expression (p < 0.01) in the spinal cord of DNP rats. Luciferase reporter assay data showed that the presumed binding site of miR-618 is located in the 3'-untranslated regions of P2Y12. MiR-618 overexpression significantly reduced P2Y12 levels (p < 0.01). Dexmedetomidine upregulated P2Y12 expression (p < 0.01) but decreased IBA-1 expression (p < 0.01). Conclusion: Dexmedetomidine application attenuates DNP by inhibiting microglial activation via the regulation of miR-618/P2Y12 pathway. This finding provides a potential therapeutic strategy for DNP management. [ABSTRACT FROM AUTHOR]

Background The balance between ischemic and bleeding events and their association with platelet reactivity in patients receiving antiplatelet therapy after percutaneous coronary intervention (PCI), which differs among regions, is not fully evaluated for East Asians. We examined ischemic/bleeding events and platelet reactivity in Japanese patients undergoing PCI and determined associations between high/low platelet reactivity and clinical outcomes. Methods and Results PENDULUM (Platelet Reactivity in Patients with Drug Eluting Stent and Balancing Risk of Bleeding and Ischemic Event) is a prospective, multicenter registry of Japanese patients with PCI. Primary end points were incidence of first major adverse cardiac and cerebrovascular events (MACCE) and first major bleeding events at 12 months post‐PCI. Platelet reactivity (P2Y12 reaction unit [PRU] value) was measured at 12 to 48 hours post‐PCI; patients were grouped as having high PRU (>208), optimal PRU (>85 to ≤208), and low PRU (≤85). MACCE and major bleeding occurred in 4.4% and 2.8% of 6267 patients, respectively. The mean±SD PRU value was 182.1±77.1. MACCE was significantly higher in the high PRU (5.7%; n=2227) versus the optimal PRU group (3.6%; n=3002). The hazard ratio (HR) for high PRU versus optimal PRU level was significantly higher for MACCE (adjusted HR, 1.53; 95% CI, 1.14–2.06 [P=0.004]); stent thrombosis followed the same trend. Incidence of major bleeding did not differ significantly between groups. A high PRU level was significantly associated with MACCE in both patients with and patients without acute coronary syndrome. Conclusions These real‐world data suggest an association between high platelet reactivity and cardiovascular events in Japanese patients undergoing PCI. The trend was the same in both patients with and patients without acute coronary syndrome. REGISTRATION URL: https://www.umin.ac.jp/ctr. Unique identifier: UMIN 000020332.

The release of ADP from platelet dense granules and its binding to platelet P2Y12 receptors is key to amplifying the initial hemostatic response and propagating thrombus formation. P2Y12 has thus emerged as a therapeutic target to safely and effectively prevent secondary thrombotic events in patients with acute coronary syndrome or a history of myocardial infarction. Pharmacological inhibition of P2Y12 receptors represents a useful approach to better understand the signaling mediated by these receptors and to elucidate the role of these receptors in a multitude of platelet hemostatic and thrombotic responses. The present work examined and compared the effects of four different P2Y12 inhibitors (MRS2395, ticagrelor, PSB 0739, and AR-C 66096) on platelet function in a series of in vitro studies of platelet dense granule secretion and trafficking, calcium generation, and protein phosphorylation. Our results show that in platelets activated with the PAR-1 agonist TRAP-6 (thrombin receptor-activating peptide), inhibition of P2Y12 with the antagonist MRS2395, but not ticagrelor, PSB 0739 or AR-C 66096, potentiated human platelet dense granule trafficking to the plasma membrane and release into the extracellular space, cytosolic Ca2+ influx, and phosphorylation of GSK3β-Ser9 through a PKC-dependent pathway. These results suggest that inhibition of P2Y12 with MRS2395 may act in concert with PAR-1 signaling and result in the aberrant release of ADP by platelet dense granules, thus reducing or counteracting the anticipated anti-platelet efficacy of this inhibitor.

Abstract Background Although prasugrel exerts stronger antiplatelet effects compared with clopidogrel, the factors affecting platelet reactivity under prasugrel have not been fully determined. This study aimed to find the novel mechanistic differences between two thienopyridines and identify the factor that influence platelet reactivity to each drug. Methods Forty patients with stable angina who underwent elective percutaneous coronary intervention were randomly assigned to receive either prasugrel (20 mg) or clopidogrel (300 mg) as a loading dose. Platelet function (light transmission, laser light scattering, and vasodilator-stimulated phosphoprotein phosphorylation) and plasma active metabolite levels were measured after the loading dose. Results Prasugrel consistently inhibited adenosine diphosphate receptor P2Y12 signalling to abolish amplification of platelet aggregation. Prasugrel abolished even small platelet aggregates composed of less than 100 platelets. On the other hand, clopidogrel inhibited large aggregates but increased small and medium platelet aggregates. Diabetes was the only independent variable for determining antiplatelet effects and active metabolite concentration of prasugrel, but not clopidogrel. Sleep-disordered breathing was significantly correlated with platelet reactivity in patients who had clopidogrel. Conclusions Prasugrel efficiently abolishes residual P2Y12 signalling that causes small platelet aggregates, but these small aggregates are not inhibited by clopidogrel. Considering the differential effect of diabetes on antiplatelet effects between these two drugs, the pharmacokinetics of prasugrel, other than cytochrome P450 metabolism, might be affected by diabetes. Trial registration UMIN-CTR UMIN000017624 , retrospectively registered 21 May 2015.

Abstract The majority of resuscitated patients present with underlying cardiac disease, and out of these myocardial infarction is most common. Immediate interventional treatment is recommended and routinely requires dual antiplatelet therapy including aspirin and a P2Y12-inhibitor. Therapeutic hypothermia or target temperature management is also recommended in these patients. Cardiogenic shock as well as reduced body temperature impacts platelet reactivity and its medical inhibition. The study aims to quantify aspirin- and P2Y12-mediated platelet inhibition in patients presenting with myocardial infarction and cardiopulmonary resuscitation. Twenty-five resuscitated patients were enrolled in this prospective, observational, non-randomized single-centre study. These patients were compared to 77 matched controls from the ATLANTIS-ACS database of non-resuscitated patients with myocardial infarction. Platelet function testing was performed by light transmittance aggregometry. Aspirin reactivity was monitored by inducing platelet aggregation with collagen and arachidonic acid, respectively. P2Y12 inhibition was recorded by stimulation of platelet aggregation with adenosine diphosphate. To quantify the overall platelet response, thrombin receptor-activated peptide was used. Aspirin-mediated platelet reactivity decreased significantly in resuscitated patients during the first days and was significantly weaker on day 3 (collagen AUC 253.8 (122.7–352.2) vs. 109.0 (73.0–182.0); p = 0.022). P2Y12-mediated platelet inhibition was also impaired in resuscitated patients on day 3 (mean ADP AUC (IQR): CPR 172.1 (46.7−346.5) vs. control 43.9 (18.9–115.2); p

Michał J Kubisa,1 Mateusz P Jezewski,1 Aleksandra Gasecka,2,3 Jolanta M Siller-Matula,4 Marek Postuła1 1Department of Experimental and Clinical Pharmacology, Centre for Preclinical Research and Technology (CEPT), 21st Chair and Department of Cardiology, Medical University of Warsaw, Warsaw, Poland; 3Vesicle Observation Centre, Laboratory of Experimental Clinical Chemistry, Academic Medical Centre, University of Amsterdam, the Netherlands; 4Department of Cardiology, Medical University of Vienna, Vienna, Austria Abstract: Novel antiplatelet drugs, including ticagrelor, are being successively introduced into the therapy of atherothrombotic conditions due to their superiority over a standard combination of clopidogrel with acetylsalicylic acid in patients with acute coronary syndromes (ACS). A P2Y12 receptor antagonist, ticagrelor, is unique among antiplatelet drugs, because ticagrelor inhibits the platelet P2Y12 receptor in a reversible manner, and because it demonstrates a wide palette of advantageous pleiotropic effects associated with the increased concentration of adenosine. The pleiotropic effects of ticagrelor comprise cardioprotection, restoration of the myocardium after an ischemic event, promotion of the release of anticoagulative factors and, eventually, anti-inflammatory effects. Beyond the advantageous effects, the increased concentration of adenosine is responsible for some of ticagrelor’s adverse effects, including dyspnea and bradycardia. Large-scale clinical trials demonstrated that both standard 12-month therapy and long-term use of ticagrelor reduce the risk of cardiovascular events in patients with ACS, but at the expense of a higher risk of major bleeding. Further trials focused on the use of ticagrelor in conditions other than ACS, including ischemic stroke, peripheral artery disease and status after coronary artery bypass grafting. The results of these trials suggest comparable efficacy and safety of ticagrelor and clopidogrel in extra-coronary indications, but firm conclusions are anticipated from currently ongoing studies. Here, we summarize current evidence on the superiority of ticagrelor over other P2Y12 antagonists in ACS, discuss the mechanism underlying the drug–drug interactions and pleiotropic effects of ticagrelor, and present future perspectives of non-coronary indications for ticagrelor. Keywords: ticagrelor, P2Y12, antiplatelet drugs, myocardial infarction, acute coronary syndromes, pleiotropism

Platelet plays a crucial role in cardiovascular diseases (CVDs) development. Abnormalities in platelet aggregation provokes thromboembolism, eventually leading to death. In Indonesia, breadfruit (Artocarpus altilis) leaf is traditionally used to treat CVDs. This study aimed to evaluate the antiplatelet activity of A. altilis leaf extract (AAE) and to identify its active compound. A. altilis leaves were extracted with ethanol, and the antiplatelet activity was assessed using ADP-induced platelet aggregation. The major compound was isolated with column chromatography followed by preparative TLC, and the structure was determined on the basis of UV, MS, IR, and NMR spectra. The binding mode of the active compound to platelet receptors was characterized in in silico study. AAE exhibited an antiplatelet activity (IC50 of 252.23 µg/mL). A geranylated chalcone, 2-geranyl-2ʹ,3,3,4ʹ-tetrahydroxydihydrochalcone (GTDC) was identified as the antiplatelet compound (IC50 of 9.09 µM). GTDC actions with P2Y12 platelet receptor involving three amino acid residues. [ABSTRACT FROM AUTHOR]

Background: Ischemic stroke is a common cause of death and disability throughout the world. We aimed to evaluate the association between polymorphisms in TBXA2R (rs4523, rs768963, rs1131882), P2Y12 (rs204693), ADD1 (rs4961) and risk of ischemic stroke.Methods: A comprehensive retrieval with the databases of Pubmed, Embase, CENTRAL, CNKI and Wan fang data was conducted. The deadline was February 1, 2019. Pooled ORs and 95% CIs were calculated by using the Z-test. Heterogeneity between the included studies was tested using the I2 method. Begg's funnel plot and Egger's linear regression were used to evaluate the publication bias. Software STATA 12.0 (StataCorp, College Station, TX, USA) was used for the meta-analysis and 26 studies with 5,776 cases and 8,025 controls were included.Results: The results indicated significantly higher risk of ischemic stroke associated with TBXA2R variant rs768963 in all genetic models (C vs T: OR=1.27, 95% CI=1.13-1.42, P. [ABSTRACT FROM AUTHOR]