scholarly journals 20(S)-Panaxadiol Enhances Hemostatic Effect on Activated Platelet by Affecting Calcium Signaling

2021 ◽  
Author(s):  
He Zhang ◽  
Wenjie Su ◽  
Chunhui Yang ◽  
Xiaolei Tang ◽  
Daian Pan ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Calcium Signaling ◽  
Glycogen Synthase ◽  
Atp Release ◽  
Panax Notoginseng ◽  
Adenosine Monophosphate ◽  
Hemorrhagic Disease ◽  
Camp Content ◽  
Hemostatic Effect

Abstract Background: Panax notoginseng (Burk.) F.H. Chen has long been used to stop bleeding for hundreds of years in China. At present, only dencichine and notoginsenoside Ft1 showed the hemostatic effect. Other ingredients from Panax notoginseng need to be further investigated. This study evaluates the hemostatic effect of 20(S)-panaxadiol (PD) and reveals its mechanism. Methods: We performed an in vivo study to measure PD on the hemostatic effect of mouse tail amputation and liver scratch models, and routine blood. Plasma coagulation parameters were measured using a blood analyzer. Platelet aggregation rate and adenosine triphosphate (ATP) release were analyzed by platelet aggregometer. Subsequently, degranulation marker P-selectin (CD62P), PAC-1 (activated GP IIb/IIIa receptor marker), the concentrations of cytosolic Ca2+ ([Ca2+]i) and cyclic adenosine monophosphate (cAMP) were also assessed. Results: PD shorted bleeding time on the mouse tail amputation and liver scratch models and mainly increased blood platelet count in the rats after subcutaneous injection of 4 h. Meanwhile, PD decreased APTT, increased FIB content, and directly induced platelet aggregation. In the absence of Ca2+, PD promoted the increase of [Ca2+]i and ATP, slightly increased CD62P expression and PAC-1 binding of platelets. After the addition of Ca2+, PD treatment markedly promoted platelet activation by releasing ATP level, increasing CD62P expression and PAC-1 binding, and decreasing cAMP level in platelets. Besides, PD increased phosphorylation of phosphoinositide 3-kinase (PI3K), protein kinase B (PKB or Akt), and glycogen synthase kinase 3β (GSK3β) in human platelets. Excitingly, PD-induced changes included platelet aggregation, a decrease of the cAMP content, and the increases of ATP, CD62P and PAC-1, which were significantly reversed by vorapaxar, which showed a similar function as thrombin. Conclusions: PD is an essential hemostatic ingredient in Panax notoginseng for promoting hematopoiesis and thrombopoiesis. PD induces platelet aggregation by affecting calcium signaling and activating PI3K/Akt/GSK3β signaling pathway, which could contribute to the new insight for the treatment of hemorrhagic disease.

scholarly journals Epithelial (E)-Cadherin is a Novel Mediator of Platelet Aggregation and Clot Stability

2019 ◽  
Vol 119 (05) ◽  
pp. 744-757 ◽  
Author(s):  
Vanessa Scanlon ◽  
Alexandra Teixeira ◽  
Tarun Tyagi ◽  
Siying Zou ◽  
Ping-Xia Zhang ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Knockout Mice ◽  
Glycogen Synthase ◽  
Conditional Knockout ◽  
Platelet Production ◽  
Conditional Knockout Mice ◽  
Clot Stability ◽  
E Cadherin

AbstractCadherins play a major role in mediating cell–cell adhesion, which shares many parallels with platelet–platelet interactions during aggregate formation and clot stabilization. Platelets express epithelial (E)-cadherin, but its contribution to platelet function and/or platelet production is currently unknown. To assess the role of E-cadherin in platelet production and function in vitro and in vivo, we utilized a megakaryocyte-specific E-cadherin knockout mouse model. Loss of E-cadherin in megakaryocytes does not affect megakaryocyte maturation, platelet number or size. However, platelet dysfunction in the absence of E-cadherin is revealed when conditional knockout mice are challenged with acute antibody-mediated platelet depletion. Unlike wild-type mice that recover fully, knockout mice die within 72 hours post-antibody administration, likely from haemorrhage. Furthermore, conditional knockout mice have prolonged tail bleeding times, unstable clot formation, reduced clot retraction and reduced fibrin deposition in in vivo injury models. Murine platelet aggregation in vitro in response to thrombin and thrombin receptor activating peptide is compromised in E-cadherin null platelets, while aggregation in response to adenosine diphosphate (ADP) is not significantly different. Consistent with this, in vitro aggregation of primary human platelets in response to thrombin is decreased by an inhibitory E-cadherin antibody. Integrin activation and granule secretion in response to ADP and thrombin are not affected in E-cadherin null platelets, but Akt and glycogen synthase kinase 3β (GSK3β) activation are attenuated, suggesting a that E-cadherin contributes to aggregation, clot stabilization and retraction that is mediated by phosphoinositide 3-kinase/Akt/GSK3β signalling. In summary, E-cadherin plays a salient role in platelet aggregation and clot stability.

scholarly journals Zinc-induced platelet aggregation is mediated by the fibrinogen receptor and is not accompanied by release or by thromboxane synthesis

Blood ◽  
1985 ◽  
Vol 66 (1) ◽  
pp. 213-219 ◽  
Author(s):  
P Heyns A du ◽  
A Eldor ◽  
R Yarom ◽  
G Marx
Keyword(s):  
Platelet Aggregation ◽  
Dense Body ◽  
Platelet Rich Plasma ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Calcium Flux ◽  
Fibrinogen Receptor ◽  
Induced Aggregation

Abstract We demonstrate that zinc (0.1 to 0.3 mmol/L) induces aggregation of washed platelet suspensions. Higher concentrations (1 to 3 mmol/L) of zinc were needed to aggregate platelets in platelet-rich plasma obtained from blood anticoagulated with low-molecular-weight heparin, probably due to the binding of zinc to the plasma proteins. Zinc- induced aggregation of normal washed platelets required added fibrinogen and no aggregation occurred with thrombasthenic platelets or with normal platelets pretreated with a monoclonal antibody (10E5) that blocks the platelet fibrinogen receptor. These data indicate that the platelet membrane fibrinogen receptor-glycoproteins IIb and IIIa mediate the effect of zinc. Zinc-induced aggregation was blocked by the agent TMB-8, which interferes with the internal calcium flux, and by prostacyclin, which elevates platelet cyclic adenosine monophosphate levels. Zinc-induced aggregation was not accompanied by thromboxane synthesis or by the secretion of dense-body serotonin and was not affected by preexposure of platelets to acetylsalicylic acid. Experiments with creatine phosphate/creatine phosphokinase showed that the zinc effect on platelets was independent of extracellular adenosine diphosphate (ADP). Zinc had an additive effect when platelet aggregation was stimulated with subthreshhold concentrations of collagen or ADP. Together with the known effects of nutritional zinc on in vivo bleeding, on platelet aggregation, and on lipid metabolism, the results suggest that zinc may have an important bearing on normal hemostasis, thrombosis, and atherosclerosis.

scholarly journals Phosphatidylinositol-3,4-Bisphosphate-Akt Signaling Pathway Promotes Platelet Activation

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1131-1131
Author(s):  
Jasna Marjanovic ◽  
Brad Rumancik ◽  
Luke Weber ◽  
Felix Wangmang ◽  
Dane Fickes ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Conflicts Of Interest ◽  
Glycogen Synthase ◽  
Thrombus Formation ◽  
Type I ◽  
Dependent Manner ◽  
Wild Type ◽  
Phosphorylated Akt

Abstract Phosphatidylinositol-3,4-bisphosphate (PtdIns(3,4)P2) is a messenger that accumulates in platelets in a phosphoinositide 3-kinase and platelet aggregation-dependent manner. PtdIns(3,4)P2 is broken down by inositol polyphosphate 4-phosphatases, type I (INPP4A) and type II (INPP4B). These enzymes do not catalyze hydrolysis of phosphoinositides other than PtdIns(3,4)P2, and therefore provide unique means for studying the role of this lipid in platelet activation. We have found that the dominant isoform of 4-phosphatases expressed in platelets is INPP4A and we have generated radiation chimera mice with the deficiency in INPP4A restricted to hematopoietic cell lineage. Compared to wild type platelets, agonist-stimulated INPP4A-deficient platelets accumulated higher levels of PtdIns(3,4)P2. An increase in platelet aggregation in INPP4A-deficient platelets was observed with all tested agonists. To study platelet function in vivo, we performed carotid artery injury mouse thrombosis model experiments. Time to occlusion was dramatically reduced in mice with INPP4A deficiency. These data support the hypothesis that by regulating PtdIns(3,4)P2 levels, INPP4A downregulates platelet aggregation and thrombus formation. To investigate mechanisms mediating INPP4A-dependent signals, we compared levels of phosphorylated Akt and phosphorylated glycogen synthase kinase (GSK) in wild type and INPP4A-deficient platelets in response to agonist stimulation. An increase in phospho-Akt levels was observed in INPP4A-deficient platelets, suggesting that in addition to its well-characterized regulator, PtdIns(3,4,5)P3, PtdIns(3,4)P2 can promote Akt activation. Interestingly, this was not accompanied by a significant increase in phospho-GSK levels, suggesting a possible novel mechanism involved in platelet aggregation. Disclosures No relevant conflicts of interest to declare.

scholarly journals Zinc-induced platelet aggregation is mediated by the fibrinogen receptor and is not accompanied by release or by thromboxane synthesis

Blood ◽  
1985 ◽  
Vol 66 (1) ◽  
pp. 213-219
Author(s):  
P Heyns A du ◽  
A Eldor ◽  
R Yarom ◽  
G Marx
Keyword(s):  
Platelet Aggregation ◽  
Dense Body ◽  
Platelet Rich Plasma ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Creatine Phosphate ◽  
Calcium Flux ◽  
Fibrinogen Receptor ◽  
Induced Aggregation

We demonstrate that zinc (0.1 to 0.3 mmol/L) induces aggregation of washed platelet suspensions. Higher concentrations (1 to 3 mmol/L) of zinc were needed to aggregate platelets in platelet-rich plasma obtained from blood anticoagulated with low-molecular-weight heparin, probably due to the binding of zinc to the plasma proteins. Zinc- induced aggregation of normal washed platelets required added fibrinogen and no aggregation occurred with thrombasthenic platelets or with normal platelets pretreated with a monoclonal antibody (10E5) that blocks the platelet fibrinogen receptor. These data indicate that the platelet membrane fibrinogen receptor-glycoproteins IIb and IIIa mediate the effect of zinc. Zinc-induced aggregation was blocked by the agent TMB-8, which interferes with the internal calcium flux, and by prostacyclin, which elevates platelet cyclic adenosine monophosphate levels. Zinc-induced aggregation was not accompanied by thromboxane synthesis or by the secretion of dense-body serotonin and was not affected by preexposure of platelets to acetylsalicylic acid. Experiments with creatine phosphate/creatine phosphokinase showed that the zinc effect on platelets was independent of extracellular adenosine diphosphate (ADP). Zinc had an additive effect when platelet aggregation was stimulated with subthreshhold concentrations of collagen or ADP. Together with the known effects of nutritional zinc on in vivo bleeding, on platelet aggregation, and on lipid metabolism, the results suggest that zinc may have an important bearing on normal hemostasis, thrombosis, and atherosclerosis.

PAK Membrane Translocation and Phosphorylation Regulate Platelet Aggregation Downstream of Gi and G12/13 Pathways

2020 ◽  
Vol 120 (11) ◽  
pp. 1536-1547
Author(s):  
Jianjun Zhang ◽  
Yan Zhang ◽  
Shuang Zheng ◽  
Yangyang Liu ◽  
Lin Chang ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Thrombus Formation ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Akt Phosphorylation ◽  
Pathway Activation ◽  
Simultaneous Activation ◽  
P21 Activated Kinase

AbstractPlatelet activation plays a pivotal role in physiological hemostasis and pathological thrombosis causing heart attack and stroke. Previous studies conclude that simultaneous activation of Gi and G12/13 signaling pathways is sufficient to cause platelet aggregation. However, using Gq knockout mice and Gq-specific inhibitors, we here demonstrated that platelet aggregation downstream of coactivation of Gi and G12/13 depends on agonist concentrations; coactivation of Gi and G12/13 pathways only induces platelet aggregation under higher agonist concentrations. We confirmed Gi and G12/13 pathway activation by showing cAMP (cyclic adenosine monophosphate) decrease and RhoA activation in platelets stimulated at both low and high agonist concentrations. Interestingly, we found that though Akt and PAK (p21-activated kinase) translocate to the platelet membrane upon both low and high agonist stimulation, membrane-translocated Akt and PAK only phosphorylate at high agonist concentrations, correlating well with platelet aggregation downstream of concomitant Gi and G12/13 pathway activation. PAK inhibitor abolishes Akt phosphorylation, inhibits platelet aggregation in vitro and arterial thrombus formation in vivo. We propose that the PAK-PI3K/Akt pathway mediates platelet aggregation downstream of Gi and G12/13, and PAK may represent a potential antiplatelet and antithrombotic target.

Abciximab treatment in vitro after aspirin treatment in vivo has additive effects on platelet aggregation, ATP release, and P-selectin expression

2000 ◽  
Vol 100 (6) ◽  
pp. 479-488 ◽  
Author(s):  
Alejandra Scazziota ◽  
Raul Altman ◽  
Jorge Rouvier ◽  
Claudio Gonzalez ◽  
Zulfiqar Ahmed ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Atp Release ◽  
Additive Effects

scholarly journals Effects of extracellular Ca++, K+, and Na+ on cone and retinal pigment epithelium retinomotor movements in isolated teleost retinas.

1984 ◽  
Vol 83 (4) ◽  
pp. 589-611 ◽  
Author(s):  
A Dearry ◽  
B Burnside
Keyword(s):  
Retinal Pigment Epithelium ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Ionic Composition ◽  
Adenosine Monophosphate ◽  
Constant Darkness ◽  
Camp Content ◽  
High K

We have examined the effects of changes in extracellular ionic composition on cone and retinal pigment epithelium (RPE) retinomotor movements in cultured isolated teleost retinas. In vivo, the myoid portion of teleost cones contracts in the light and elongates in the dark; RPE pigment disperses in the light and aggregates in the dark. In vitro, cones of dark-adapted (DA) retinas cultured in constant darkness contracted spontaneously to their light-adapted (LA) positions if the culture medium contained greater than or equal to 10(-3)M Cao++. DA cones retained their long DA positions in a medium containing less than or equal to 10(-6)M Cao++. Low [Ca++]o (10(-5)-10(-7)M) also permitted darkness to induce cone elongation and RPE pigment aggregation. Light produced cone contraction even in the absence of Cao++, but the extent of contraction was reduced if [Ca++]o was less than 10(-3) M. Thus, full contraction appeared to require the presence of external Ca++. High [K+]o (greater than or equal to 27 mM) inhibited both light-induced and light-independent Ca++-induced cone contraction. However, low [Na+]o (3.5 mM) in the presence of less than or equal to 10(-6)M Cao++ did not mimic light onset by inducing cone contraction in the dark. High [K+]o also promoted dark-adaptive cone and RPE movements in LA retinas cultured in the light. All results obtained in high [K+]o were similar to those observed when DA or LA retinas were exposed to treatments that elevate cytoplasmic cyclic 3',5'-adenosine monophosphate (cAMP) content.

scholarly journals AN IMPORTANT STIMULATORY ROLE FOR THE cGMP-DEPENDENT PROTEIN KINASE II IN PLATELET ACTIVATION, IN VIVO THROMBOSIS AND HAEMOSTASIS

2020 ◽  
Author(s):  
Zhenyu Li ◽  
Ying Liang ◽  
can wang ◽  
Guoying Zhang ◽  
Jens Schlossmann ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Bleeding Time ◽  
Thrombus Formation ◽  
Atp Release ◽  
Downstream Signaling ◽  
Dependent Protein ◽  
Deficient Mice

Background and Purpose: The intracellular second messenger cGMP mediates signals by activating two types of cGMP-dependent protein kinases (PKG), PKG I and PKG II, differentially expressed in different cells. In platelets, cGMP mediates biphasic signals that stimulate and inhibit platelet activation, and the downstream signaling of cGMP is mediated by PKG I, the only PKG known to be expressed in platelets. However, functional defects of PKG I knockout platelets did not fully explain the roles of cGMP and the effect of PKG inhibitors on platelet activation. Experimental Approach: To determine if PKG II is present in platelets and plays a role in platelet activation, we performed RT-PCR and isolation of PKG II protein using cGMP-conjugated beads. We further determined platelet aggregation and ATP release in vitro, and FeCl3-injured carotid artery thrombosis as well as tail bleeding time in vivo. Key Results: PKG II is expressed in platelets and plays an important role in selectively stimulating platelet activation but not in the negative regulatory role of cGMP. Collagen-induced platelet aggregation and ATP secretion were reduced in PKG II-deficient mice but not PKG I-deficient mice. In contrast, low-dose thrombin-induced platelet activation depended on PKG I but not PKG II. Tail bleeding time and FeCl3-induced artery thrombus formation were significantly prolonged in PKG II knockout mice. Conclusion and Implication: PKG II-mediated cGMP signals are important in platelet activation, thrombosis and haemostasis in vitro and in vivo.

Antithrombotic Effects and Bleeding Time Prolongation with Synthetic Platelet GPIIb/llla Inhibitors in Animal Models of Platelet-Mediated Thrombosis

1994 ◽  
Vol 71 (01) ◽  
pp. 095-102 ◽  
Author(s):  
Désiré Collen ◽  
Hua Rong Lu ◽  
Jean-Marie Stassen ◽  
Ingrid Vreys ◽  
Tsunehiro Yasuda ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Bleeding Time ◽  
Bolus Injection ◽  
Cell Injury ◽  
Ex Vivo ◽  
Thrombus Formation ◽  
Femoral Vein ◽  
Thrombotic Occlusion ◽  
Antithrombotic Effects

SummaryCyclic Arg-Gly-Asp (RGD) containing synthetic peptides such as L-cysteine, N-(mercaptoacetyl)-D-tyrosyl-L-arginylglycyl-L-a-aspartyl-cyclic (1→5)-sulfide, 5-oxide (G4120) and acetyl-L-cysteinyl-L-asparaginyl-L-prolyl-L-arginyl-glycyl-L-α-aspartyl-[0-methyltyrosyl]-L-arginyl-L-cysteinamide, cyclic 1→9-sulfide (TP9201) bind with high affinity to the platelet GPIIb/IIIa receptor.The relationship between antithrombotic effect, ex vivo platelet aggregation and bleeding time prolongation with both agents was studied in hamsters with a standardized femoral vein endothelial cell injury predisposing to platelet-rich mural thrombosis, and in dogs with a carotid arterial eversion graft inserted in the femoral artery. Intravenous administration of G4120 in hamsters inhibited in vivo thrombus formation with a 50% inhibitory bolus dose (ID50) of approximately 20 μg/kg, ex vivo ADP-induccd platelet aggregation with ID50 of 10 μg/kg, and bolus injection of 1 mg/kg prolonged the bleeding time from 38 ± 9 to 1,100 ± 330 s. Administration of TP9201 in hamsters inhibited in vivo thrombus formation with ID50 of 30 μg/kg, ex vivo platelet aggregation with an ID50 of 50 μg/kg and bolus injection of 1 mg/kg did not prolong the template bleeding time. In the dog eversion graft model, infusion of 100 μg/kg of G4120 over 60 min did not fully inhibit platelet-mediated thrombotic occlusion but was associated with inhibition of ADP-induccd ex vivo platelet aggregation and with prolongation of the template bleeding time from 1.3 ± 0.4 to 12 ± 2 min. Infusion of 300 μg/kg of TP9201 over 60 min completely prevented thrombotic occlusion, inhibited ex vivo platelet aggregation, but was not associated with prolongation of the template bleeding time.TP9201, unlike G4120, inhibits in vivo platelet-mediated thrombus formation without associated prolongation of the template bleeding time.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

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