P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectin-induced calcium signaling of neutrophils in flow.
Calcium Signaling ; Female ; Humans ; Male ; Membrane Glycoproteins ; metabolism ; Neutrophils ; metabolism ; P-Selectin ; metabolism ; Stress, Mechanical ; Syk Kinase ; metabolism

The opening of mitochondrial permeability transition pore (MPTP) plays a critical role in platelet activation. However, the potential trigger of the MPTP opening in platelet activation remains unknown. Inflammation is the crucial trigger of platelet activation. In this study, we aimed to explore whether and how the important inflammatory cytokine IL-17 is associated with MPTP opening in platelets activation by using MPTP inhibitor cyclosporine-A (CsA). The mitochondrial membrane potential (ΔΨm) was detected to reflect MPTP opening levels. And the platelet aggregation, activation, and the primary signaling pathway were also tested. The results showed that the MPTP opening levels were increased and Δψm reduced in platelets administrated with IL-17. Moreover, the levels of aggregation, CD62P, PAC-1, P53 and the phosphorylation of ERK2 were enhanced along with the MPTP opening in platelets pre-stimulated with IL-17. However, CsA attenuated these effects triggered by IL-17. It was suggested that IL-17 could induce MPTP opening through ERK2 and P53 signaling pathway in platelet activation and aggregation.
Blood Platelets ; cytology ; drug effects ; metabolism ; Cell Separation ; Cyclosporine ; pharmacology ; Dual Specificity Phosphatase 2 ; genetics ; metabolism ; Gene Expression Regulation ; Humans ; Interleukin-17 ; metabolism ; pharmacology ; Membrane Potential, Mitochondrial ; drug effects ; Mitochondria ; drug effects ; metabolism ; Mitochondrial Membrane Transport Proteins ; agonists ; antagonists & inhibitors ; genetics ; metabolism ; Mitogen-Activated Protein Kinase 1 ; genetics ; metabolism ; P-Selectin ; genetics ; metabolism ; Phosphorylation ; drug effects ; Platelet Activation ; drug effects ; Platelet Aggregation ; drug effects ; Primary Cell Culture ; Signal Transduction ; Tumor Suppressor Protein p53 ; genetics ; metabolism

<p>OBJECTIVETo investigate the effect of component I from agkistrodon acutus venomon (AAVC-I) the migration of human umbilical vein endothelial cells (HUVECs), and to elucidate the possible anti-angiogenic mechanism of AAVC-I.p><p>METHODSThe effect of AAVC-I on the migration of HUVECs which was cultivated in vitro and treated with AAVC-1 at four concentrations: 0, 20, 40, 80 microg/ml, was observed by methods of scratch wound-healing and Transwell assay. The expression level of mRNA and protein of P-selectin and intercellular cell adhension molecule-I (ICAM-1) were examined by RT-PCR and Western blot assay.p><p>RESULTSCompared with the blank group, the migration ability of HUVECs in each AAVE-I treated group was reduced in a dose-dependent manner, and the expression level of the mRNA and protein of P-selectin and ICAM-1 were decreased.p><p>CONCLUSIONAAVC-I inhibits the migration of endothelial cell, which is acted by down-regulation of the expression content of mRNA and protein of P-selectin and ICAM-1.p>
Cell Movement ; drug effects ; Cells, Cultured ; Crotalid Venoms ; pharmacology ; Down-Regulation ; Human Umbilical Vein Endothelial Cells ; drug effects ; Humans ; Intercellular Adhesion Molecule-1 ; metabolism ; P-Selectin ; metabolism ; RNA, Messenger

<p>OBJECTIVETo study the effect of aqueous extract of several kinds of herbs on human platelet aggregation and expression of P-selectin in vitro.p><p>METHODSBlood was collected from volunteers. Effects of the prepared water extracts of herbs on platelet aggregation were monitored on a Packs-4 aggregometer. The fluorescence intensity of water extracts of Caulis Spatholobi, Flos Carthami and Rhizoma Curcumae on the expression of P-selectin in human platelets of healthy persons was measured with flow cytometry.p><p>RESULTSOut of several herbs investigated, Flos Carthami and Rhizoma Curcumae potently inhibited platelet aggregation after incubation with platelet-rich plasma (PRP) for 15 min. Caulis Spatholobi Flos Carthami and Rhizoma Curcumae inhibited adenosine-5'-diphosphate (ADP) or platelet activating factor (PAF)-induced platelet aggregation in PRP in a dose-dependent manner. In contrast to Flos Carthami and Rhizoma Curcumae, Caulis Spatholobi could not inhibit thrombin-induced platelet aggregation. Despite its inability to inhibit thrombin-induced platelet aggregation in PRP, Caulis Spatholobi had a greater anti-aggregating activity in PRP induced by ADP or PAF. Caulis Spatholobi and Flos Carthami showed significant inhibitory effects on the expression of P-selectin.p><p>CONCLUSIONSCaulis Spatholobi, Flos Carthami and Rhizoma Curcumae have potent anti-platelet properties, and their inhibitory actions are mediated via different mechanisms. Caulis Spatholobi inhibited ADP-induced platelet aggregation but not by thrombin, indicating that its mechanism of action might be independent of the thromboxane pathway. The effect of Caulis Spatholobi and Flos Carthami were associated with suppressing the expression of P-selectin.p>
Adult ; Blood Platelets ; drug effects ; metabolism ; Curcuma ; chemistry ; Fabaceae ; chemistry ; Humans ; P-Selectin ; metabolism ; Plant Extracts ; chemistry ; pharmacology ; Plants, Medicinal ; chemistry ; Platelet Aggregation ; drug effects ; Platelet Function Tests ; Water ; chemistry ; Young Adult

Vascular adventitial fibroblasts (AF) may play an important role in vascular inflammation. This study was aimed to investigate the expression pattern of inflammatory mediators in AF induced by angiotensin II (AngII) and to explore the effects of AF-derived inflammatory mediators on the adhesion and migration of macrophages both in vitro and in vivo. We used real-time RT-PCR to detect the mRNA expression of inflammatory mediators in cultured AF. The results showed that AngII (1 × 10(-7) mol/L) up-regulated mRNA expression of 4 inflammatory mediators, including P-selectin, ICAM-1, IL-6 and MCP-1, in cultured AF. Western blot analysis or ELISA revealed that AngII up-regulated P-selectin and ICAM-1 protein expression and IL-6 secretion in cultured AF, but did not alter MCP-1 secretion. We further detected the effects of AF-derived inflammatory mediators on the adhesion and chemotaxis of RAW264.7, a macrophage cell line. We found that AF stimulated with AngII could enhance the adhesion of RAW264.7 and the conditioned medium from AngII-stimulated AF could enhance the migration of RAW264.7. Immunofluorescence study showed an enhanced accumulation of CD68 positive cells and the up-regulation of P-selectin, ICAM-1, IL-6 and MCP-1 in aortic adventitia of AngII-infused (200 ng/kg per min for 2 weeks) rats. We concluded that AF may contribute to vascular inflammation via expression of certain inflammatory mediators and the subsequent adhesion and chemotaxis of macrophages.
Adventitia ; drug effects ; Angiotensin II ; pharmacology ; Animals ; Cell Line ; Chemokine CCL2 ; metabolism ; Culture Media, Conditioned ; Fibroblasts ; drug effects ; immunology ; Inflammation ; immunology ; Intercellular Adhesion Molecule-1 ; metabolism ; Interleukin-6 ; metabolism ; Macrophages ; drug effects ; immunology ; Mice ; P-Selectin ; metabolism ; RAW 264.7 Cells ; Rats ; Up-Regulation

<p>OBJECTIVETo investigate the effect of atorvastatin on platelet aggregation and activation in the acute phase following balloon-induced carotid artery injury in rabbits fed cholesterol-enriched diet.p><p>METHODSThirty rabbits were randomly divided into 5 equal groups, namely control group, high-cholesterol group, model group, low-dose (5 mg/kg daily) atorvastatin group, and high-dose (10 mg/kg daily) atorvastatin group. Platelet aggregation rate was measured in the rabbits by turbidimetric platelet aggregometry, and the changes of serum P-selectin and thromboxane B2 (TXB2) levels were detected with enzyme-linked immunosorbent assay (ELISA).p><p>RESULTSCompared with those in the control group, serum P-selectin level increased significantly (P<0.01) but platelet aggregation rate and TXB2 level exhibited no obvious changes in high-cholesterol group. After carotid artery balloon injury, P-selectin and TXB2 levels and platelet aggregation significantly increased in cholesterol-fed rabbits, reaching the peak level at 24 h after the injury (P<0.01). Compared with the model group, low-dose atorvastatin treatment significantly decreased P-selectin and TXB2 levels and inhibited platelet aggregation in cholesterol-fed rabbits following carotid artery balloon injury (P<0.01), and such effects of atorvastatin were more prominent at a higher daily dose of 10 mg/kg (P<0.05).p><p>CONCLUSIONSCarotid artery balloon injury in rabbits fed cholesterol-enriched diet can induce platelet activation and aggregation, which reaches the peak level at 24 h after balloon injury and can be dose-dependently inhibited by atorvastatin in the acute phase following the injury.p>
Animals ; Atorvastatin Calcium ; Blood Platelets ; Carotid Artery Injuries ; drug therapy ; Cholesterol ; Enzyme-Linked Immunosorbent Assay ; Heptanoic Acids ; pharmacology ; P-Selectin ; metabolism ; Platelet Activation ; Platelet Aggregation ; Pyrroles ; pharmacology ; Rabbits ; Thromboxane B2 ; metabolism

This study was purposed to explore the influence of S-nitrosoglutathione (GSNO) on membrane glycoprotein of frozen platelet. The levels of membrane glycoprotein on fresh liquid platelets, frozen platelets and frozen platelets with GSNO were measured by flow cytometry. The results showed that the GSNO obviously decreased platelet aggregation, the PAC-1 change in the three groups was not significant. The changes of CD42b and CD62P in fresh liquid platelet group, frozen platelet group and frozen platelets with GSNO were significant different. The change of membrane glycoprotein in above-mentioned three group was not significant. It is concluded that the GSNO inhibits platelet aggregation, maintains the function of platelets and may be used as a cryoprotectant. When frozen platelets were added with GSNO, the molecular rearrangement, structure change and other mechanism may occur in platelets.
Blood Platelets ; drug effects ; Blood Preservation ; methods ; Freezing ; Humans ; P-Selectin ; metabolism ; Platelet Activation ; drug effects ; Platelet Glycoprotein GPIb-IX Complex ; metabolism ; Platelet Membrane Glycoproteins ; metabolism ; S-Nitrosoglutathione ; pharmacology

Animals ; Hindlimb ; blood supply ; Ischemic Preconditioning ; Lung ; metabolism ; Male ; P-Selectin ; metabolism ; Rats ; Rats, Wistar ; Reperfusion Injury ; metabolism

This study was aimed to investigate the changes of the platelet particle membrane protein (GMP-140), platelet activating factor (PAF) and platelet parametes in the patients with hyperuricemia (HUA), ELISA was used to detect the levels of GMP-140 and PAF in 55 patients with HUA and 30 healthy individuals. Platelet parameters were measured with automatic blood cell analyzer, and the biochemical indexes were detected at the same time. The results showed that the levels of serum uric acid, triglycerides (TG) and low density lipoprotein cholesterol (LDL-C) in HUA patients were higher than that in the normal group (P < 0.01). Serum uric acid level of HUA group was higher in men than that in women. The levels of GMP-140 and PAF in HUA patients were much higher than that in the normal group (P < 0.01), the indexes of platelet distribution width (PDW) and platelet-large cell ratio (P-LCR) in HUA patients were higher than that in the normal group (P < 0.01), there was no statistically significant difference in platelet count, plateletcrit (PCT), mean platelet volume (MPV) between the two groups. There was positive correlation between serum uric acid and levels of GMP-140, PAF, P-LCR and PDW, respectively (r = 0.667, 0.879, 0.310, 0.460, P < 0.01 or P < 0.05). Multivariate stepwise regression analysis revealed that serum uric acid, creatinine, P-LCR, urea nitrogen contributed to GMP-140 level (adjusted R(2) = 0.822). Serum uric acid and LDL-C also contributed to PAF level (adjusted R(2) = 0.451). It is concluded that a close relationship exists between HUA and the change of platelet function, and HUA plays a certain role in cardiovascular disease thrombosis complications.
Adult ; Aged ; Blood Platelets ; metabolism ; Case-Control Studies ; Female ; Humans ; Hyperuricemia ; blood ; Male ; Middle Aged ; P-Selectin ; metabolism ; Platelet Activating Factor ; metabolism ; Platelet Count

<p>OBJECTIVETo investigate the effect of Helicobacter pylori (Hp) on platelet activation and coagulation function in patients with acute cerebral infarction.p><p>METHODSSixty-six patients with acute cerebral infarction and 50 health individuals were enrolled in the study. Hp antibody,expression of CD62p on platelets and clotting indexes were measured and compared between two groups.p><p>RESULTSThe positive rate of Hp-IgG and Hp-CagA in cerebral infarction patients were higher than that in controls (P<0.05). The positive rate of CD62p in patients with positive Hp-IgG and Hp-CagA was significantly higher than that in negative patients and also controls (P<0.05). The APTT and TT were lower and FIB was higher in patients with positive Hp antibody than those in patients with negative Hp antibody (P<0.05),but there was no difference in PT,PTR and INR (P>0.05).p><p>CONCLUSIONHp infection can activate platelets and affect coagulation function,which may be involved in the development of cerebral infarction.p>
Adult ; Aged ; Antibodies, Bacterial ; blood ; Antigens, Bacterial ; metabolism ; Bacterial Proteins ; metabolism ; Blood Coagulation ; Case-Control Studies ; Cerebral Infarction ; blood ; microbiology ; Female ; Helicobacter Infections ; blood ; complications ; Helicobacter pylori ; metabolism ; pathogenicity ; Humans ; Immunoglobulin G ; blood ; Male ; Middle Aged ; P-Selectin ; blood ; Platelet Activation