Group B streptococcus isolates from septic patients and healthy carriers differentially activate platelet signaling cascades

2006 ◽  
Vol 95 (05) ◽  
pp. 836-849 ◽  
Author(s):  
Catharina Dornieden ◽  
Claudia Beyrich ◽  
Birgitta Schinke ◽  
Alexandra Schubert-Unkmeir ◽  
Marianne Abele-Horn ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Protein Kinase ◽  
Shape Change ◽  
Group B Streptococcus ◽  
Neonatal Morbidity ◽  
P38 Map Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Calcium Calmodulin Dependent ◽  
Group B ◽  
Platelet Thromboxane

SummaryInfection with group B streptococcus (GBS) is the most common cause of early onset neonatal sepsis in many countries, leading to neonatal morbidity and mortality.There is much evidence fora direct involvement of platelets in the pathogenesis of inflammation and sepsis. Several bacteria are known to directly interact with platelets leading to activation and aggregation,a phenomenon also observed with GBS. Here, we demonstrate that GBS rapidly bound to platelets; however, only strains isolated from septic patients bound fibrinogen on their surface and induced platelet thromboxane synthesis, platelet aggregation, and P-selectin (CD62P) expression. In contrast, GBS strains isolated from healthy newborns or healthy pregnant women induced only shape change, but not platelet thromboxane synthesis, platelet aggregation, or CD62P expression. All GBS strains investigated were able to activate FcγRIIA receptor signaling pathways including phospholipase C gamma2 (PLCγ2), as well as calcium/calmodulin-dependent myosin kinase II (CaMKII) and phosphorylation of myosin light chain (MLC). In contrast, protein kinase C (PKC) was exclusively activated by GBS strains isolated from septic patients, and p38 mitogen activated protein kinase (p38 MAP kinase) was preferentially activated by septic GBS strains. Furthermore, stress signaling kinase SEK1/MKK4 and focal adhesion kinase (FAK) were activated by all tested GBS strains in a FcγRIIA-independent way.This study demonstrates that septic, but not colonizing, GBS strains bind fibrinogen on their surface, and that septic GBS strains influence platelet function not only via the FcγRIIA receptor, but also via pathways distinct from IgG-mediated signalling. These mechanisms lead to platelet aggregation and secretion, thereby possibly modulating the pathophysiologic course of GBS infections.

scholarly journals Trends in molecular characteristics and antimicrobial resistance of group B streptococci: a multicenter study in Serbia, 2015–2020

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dusan Kekic ◽  
Ina Gajic ◽  
Natasa Opavski ◽  
Milan Kojic ◽  
Goran Vukotic ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Late Onset ◽  
Group B Streptococcus ◽  
Neonatal Morbidity ◽  
Disease Rate ◽  
Molecular Characteristics ◽  
Group B Streptococci ◽  
Live Births ◽  
Invasive Infections ◽  
Group B

AbstractGroup B Streptococcus (GBS) is a major cause of neonatal morbidity and mortality. Serbia has not fully implemented preventive measures against GBS neonatal diseases. Therefore, we aimed to assess the maternal GBS colonisation and invasive neonatal disease rate, to reveal the trends of antimicrobial resistance and serotype distribution of GBS from various patient groups. Randomly selected non-invasive (n = 991) and all invasive GBS (n = 80) collected throughout Serbia from 2015 to 2020 were tested for antimicrobial susceptibility, capsular typing, and hvgA detection. Overall, 877/5621 (15.6%) pregnant women were colonised with GBS. Invasive GBS infections incidence in infants (0.18/1000 live births) showed a decreasing trend (0.3 to 0.1/1000 live births). Type III was overrepresented in infants with invasive infections (n = 35, 58.3%), whereas type V predominated among colonised adults (n = 224, 25.5%) and those with noninvasive (n = 37, 32.5%) and invasive infections (n = 8, 40%). The hypervirulent clone III/ST17 was highly associated with invasive infections (n = 28, 35%), particularly late-onset disease (n = 9, 47.4%), showing an increase from 12.3 to 14.8%. The GBS resistance to erythromycin and clindamycin was 26.7% and 22.1%, respectively, with an upward trend. The emergence of the hypervirulent clone III/ST17 and the escalation in GBS resistance highlight an urgent need for continuous monitoring of GBS infections.

scholarly journals Prostacyclin inhibits platelet aggregation induced by phorbol ester or Ca2+ ionophore at steps distal to activation of protein kinase C and Ca2+-dependent protein kinases

1989 ◽  
Vol 258 (1) ◽  
pp. 57-65 ◽  
Author(s):  
W Siess ◽  
E G Lapetina
Keyword(s):  
Protein Kinase C ◽  
Platelet Aggregation ◽  
Protein Kinase ◽  
Protein Kinases ◽  
Shape Change ◽  
Ionophore A23187 ◽  
Maximal Effect ◽  
Kinase C ◽  
Dependent Protein ◽  
High Concentrations

Suspensions of aspirin-treated, 32P-prelabelled, washed platelets containing ADP scavengers in the buffer were activated with either phorbol 12,13-dibutyrate (PdBu) or the Ca2+ ionophore A23187. High concentrations of PdBu (greater than or equal to 50 nM) induced platelet aggregation and the protein kinase C (PKC)-dependent phosphorylation of proteins with molecular masses of 20 (myosin light chain), 38 and 47 kDa. No increase in cytosolic Ca2+ was observed. Preincubation of platelets with prostacyclin (PGI2) stimulated the phosphorylation of a 50 kDa protein [EC50 (concn. giving half-maximal effect) 0.6 ng of PGI2/ml] and completely abolished platelet aggregation [ID50 (concn. giving 50% inhibition) 0.5 ng of PGI2/ml] induced by PdBu, but had no effect on phosphorylation of the 20, 38 and 47 kDa proteins elicited by PdBu. The Ca2+ ionophore A23187 induced shape change, aggregation, mobilization of Ca2+, rapid phosphorylation of the 20 and 47 kDa proteins and the formation of phosphatidic acid. Preincubation of platelets with PGI2 (500 ng/ml) inhibited platelet aggregation, but not shape change, Ca2+ mobilization or the phosphorylation of the 20 and 47 kDa proteins induced by Ca2+ ionophore A23187. The results indicate that PGI2, through activation of cyclic AMP-dependent kinases, inhibits platelet aggregation at steps distal to protein phosphorylation evoked by protein kinase C and Ca2+-dependent protein kinases.

Functional Role of p38 Mitogen Activated Protein Kinase in Platelet Activation induced by a Thromboxane A2 Analogue and by 8-iso-prostaglandin F2 α

2002 ◽  
Vol 87 (05) ◽  
pp. 888-898 ◽  
Author(s):  
Stefania Gaino ◽  
Valeria Zuliani ◽  
Rosa Tommasoli ◽  
Donatella Benati ◽  
Riccardo Ortolani ◽  
...  
Keyword(s):  
Map Kinase ◽  
Platelet Activation ◽  
Tyrosine Kinases ◽  
Actin Polymerization ◽  
Shape Change ◽  
Specific Inhibitor ◽  
P38 Map Kinase ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Kinase Phosphorylation

SummaryWe investigated similarities in the signaling pathways elicited by the F2 isoprostane 8-iso-PGF2α and by low doses of U46619 to induce platelet activation. Both 0.01-0.1 µmol/L U46619 and 0.01-1 µmol/L 8-isoPGF2α triggered shape change and filopodia extension, as well as adhesion to immobilized fibrinogen of washed platelets. At these doses the two platelet agonists failed to trigger secretion and aggregation, which were however induced by higher doses of U46619 (0.1-1 µmol/L). SB203580 (1-10 µmol/L), a specific inhibitor of the p38 mitogen activated protein (MAP) kinase blunted platelet shape change and adhesion induced by 0.05-1 µmol/L 8-iso-PGF2α and by 0.01 µmol/L U46619. These platelet responses were also inhibited by 20 µmol/L cytochalasin D, an inhibitor of actin polymerization, and 50 µmol/L piceatannol, an inhibitor of the Syk tyrosine kinases. Both 8-iso-PGF2α and U46619-induced p38 MAP kinase phosphorylation in suspended platelets and this was inhibited by piceatannol, indicating that Syk activation occurs upstream p38 MAP kinase phosphorylation. These findings suggest that the signaling pathway triggered by both 8-iso-PGF2α and low concentrations of U46619 to induce platelet adhesion and shape change implicates Syk, the p38 MAP kinase, and actin polymerization.

scholarly journals Infection of Human Coronary Artery Endothelial Cells by Group B Streptococcus Contributes to Dysregulation of Apoptosis, Hemostasis, and Innate Immune Responses

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Claudia Beyrich ◽  
Jürgen Löffler ◽  
Anna Kobsar ◽  
Christian P. Speer ◽  
Susanne Kneitz ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Coronary Artery ◽  
Group B Streptococcus ◽  
Gene Array ◽  
Neonatal Morbidity ◽  
Innate Immune ◽  
Human Coronary Artery ◽  
Chemotactic Protein ◽  
Early Onset Sepsis ◽  
Group B

Early onset sepsis due to group B streptococcus leads to neonatal morbidity, increased mortality, and long-term neurological deficencies. Interaction between septicemic GBS and confluent monolayers of human coronary artery endothelial cells (HCAECs) was analyzed by genome wide expression profiling. In total, 124 genes were differentially expressed (89 upregulated, 35 downregulated) based on a more than 3-fold difference to control HCAEC. Regulated genes are involved in apoptosis, hemostasis, oxidative stress response, infection, and inflammation. Regulation of selected genes and proteins identified in the gene array analysis was confirmed by Real-time RT-PCR assay (granulocyte chemotactic protein 2), ELISA (urokinase, cyclooxygenase 2, granulocyte chemotactic protein 1), and western blotting (Heme oxygenase1, BCL2 interacting protein) at various time points between 4 and 24 hours. These results indicate that GBS infection might influence signalling pathways leading to impaired function of the innate immune system and hemorrhagic and inflammatory complications during GBS sepsis.

Effect of selective inhibition of the p38 MAP kinase pathway on platelet aggregation

2004 ◽  
Vol 92 (12) ◽  
pp. 1387-1393 ◽  
Author(s):  
Athan Kuliopulos ◽  
Ramon Mohanlal ◽  
Lidija Covic
Keyword(s):  
Platelet Aggregation ◽  
P38 Mapk ◽  
Coronary Intervention ◽  
Selective Inhibition ◽  
P38 Map Kinase ◽  
Significant Inhibition ◽  
Mitogen Activated Protein Kinase ◽  
Thromboxane Production ◽  
Mapk Inhibitor

SummarySystemic inflammation has been shown to be a contributing factor to the instability of atherosclerotic plaques in patients with acute coronary syndromes (ACS). VX-702, a novel p38 mitogen-activated protein kinase (MAPK) inhibitor, is currently under investigation in ACS patients with unstable angina to evaluate its safety and efficacy during percutaneous coronary intervention (PCI).The role of p38 MAPK in platelet aggregation of normal individuals was examined using the selective second generation p38 MAPK inhibitor VX-702. Treatment of platelets with thrombin (activates PAR1 and PAR4 thrombin receptors), SFLLRN (PAR1), AYPGKF (PAR4), collagen (α2β1 and GPVI/FCγIIR receptors) and U46619 (TXA2) resulted in strong activation of p38 MAPK. Activation of the GPIb von Willebrand factor receptor with ristocetin did not stimulate p38 MAPK. Pre-treatment of platelets with 1 μM VX-702 completely inhibited activation of p38 MAPK by thrombin, SFLLRN, AYPGKF, U46619, and collagen. There was no effect of VX-702 on platelet aggregation induced by any of the agonists in the presence or absence of aspirin, heparin or apyrase. It has been postulated that a potential role of p38 MAPK is to activate phospholipase A2 (cPLA2) which catalyses formation of arachidonic acid leading to production of thromboxane. Interestingly, we show contrasting effects of p38 MAPK inhibition as compared to aspirin inhibition on platelet aggregation in response to collagen. Blockade of TXA2 production by aspirin results in significant inhibition of collagen activation. However, VX-702 has no effect on collagen-mediated platelet aggregation, suggesting that blocking p38 MAPK does not effect thromboxane production in human platelets. Therefore, unlike aspirin blockade of thromboxane production in platelets, p38 MAPK inhibitors such as VX-702 do not significantly affect platelet function and would not be expected to contribute to an elevated risk of bleeding side-effects in treated patients.

scholarly journals Lipopolysaccharide-Induced Matrix Metalloproteinase-9 Expression Associated with Cell Migration in Rat Brain Astrocytes

2019 ◽  
Vol 21 (1) ◽  
pp. 259 ◽  
Author(s):  
Chien-Chung Yang ◽  
Chih-Chung Lin ◽  
Li-Der Hsiao ◽  
Jing-Ming Kuo ◽  
Hui-Ching Tseng ◽  
...  
Keyword(s):  
Cell Migration ◽  
Protein Kinase ◽  
Matrix Metalloproteinase ◽  
Rat Brain ◽  
P38 Map Kinase ◽  
Tanshinone Iia ◽  
Mitogen Activated Protein Kinase ◽  
Brain Diseases ◽  
Amino Terminal ◽  
Tyrosine Kinase 2

Neuroinflammation is a landmark of neuroinflammatory and neurodegenerative diseases. Matrix metalloproteinase (MMP)-9, one member of MMPs, has been shown to contribute to the pathology of these brain diseases. Several experimental models have demonstrated that lipopolysaccharide (LPS) exerts a pathological role through Toll-like receptors (TLRs) in neuroinflammation and neurodegeneration. However, the mechanisms underlying LPS-induced MMP-9 expression in rat brain astrocytes (RBA-1) are not completely understood. Here, we applied pharmacological inhibitors and siRNA transfection to assess the levels of MMP-9 protein, mRNA, and promoter activity, as well as protein kinase phosphorylation in RBA-1 cells triggered by LPS. We found that LPS-induced expression of pro-form MMP-9 and cell migration were mediated through TLR4, proto-oncogene tyrosine-protein kinase (c-Src), proline-rich tyrosine kinase 2 (Pyk2), platelet-derived growth factor receptor (PDGFR), phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), p38 mitogen-activated protein kinase (MAPK), and Jun amino-terminal kinase (JNK)1/2 signaling molecules in RBA-1 cells. In addition, LPS-stimulated binding of c-Jun to the MMP-9 promoter was confirmed by chromatin immunoprecipitation (ChIP) assay, which was blocked by pretreatment with c-Src inhibitor II, PF431396, AG1296, LY294002, Akt inhibitor VIII, p38 MAP kinase inhibitor VIII, SP600125, and tanshinone IIA. These results suggest that in RBA-1 cells, LPS activates a TLR4/c-Src/Pyk2/PDGFR/PI3K/Akt/p38 MAPK and JNK1/2 pathway, which in turn triggers activator protein 1 (AP-1) activation and ultimately induces MMP-9 expression and cell migration.

scholarly journals MerTK signaling in macrophages promotes the synthesis of inflammation resolution mediators by suppressing CaMKII activity

2018 ◽  
Vol 11 (549) ◽  
pp. eaar3721 ◽  
Author(s):  
Bishuang Cai ◽  
Canan Kasikara ◽  
Amanda C. Doran ◽  
Rajasekhar Ramakrishnan ◽  
Raymond B. Birge ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Inflammatory Diseases ◽  
Critical Role ◽  
Mitogen Activated Protein Kinase ◽  
Gene Encoding ◽  
Endoplasmic Reticulum Calcium ◽  
Calcium Calmodulin Dependent ◽  
Mitogen Activated Protein ◽  
Dependent Protein ◽  
Inflammation Resolution

Inflammation resolution counterbalances excessive inflammation and restores tissue homeostasis after injury. Failure of resolution contributes to the pathology of numerous chronic inflammatory diseases. Resolution is mediated by endogenous specialized proresolving mediators (SPMs), which are derived from long-chain fatty acids by lipoxygenase (LOX) enzymes. 5-LOX plays a critical role in the biosynthesis of two classes of SPMs: lipoxins and resolvins. Cytoplasmic localization of the nonphosphorylated form of 5-LOX is essential for SPM biosynthesis, whereas nuclear localization of phosphorylated 5-LOX promotes proinflammatory leukotriene production. We previously showed that MerTK, an efferocytosis receptor on macrophages, promotes SPM biosynthesis by increasing the abundance of nonphosphorylated, cytoplasmic 5-LOX. We now show that activation of MerTK in human macrophages led to ERK-mediated expression of the gene encoding sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2), which decreased the cytosolic Ca2+ concentration and suppressed the activity of calcium/calmodulin-dependent protein kinase II (CaMKII). This, in turn, reduced the activities of the mitogen-activated protein kinase (MAPK) p38 and the kinase MK2, resulting in the increased abundance of the nonphosphorylated, cytoplasmic form of 5-LOX and enhanced SPM biosynthesis. In a zymosan-induced peritonitis model, an inflammatory setting in which macrophage MerTK activation promotes resolution, inhibition of ERK activation delayed resolution, which was characterized by an increased number of neutrophils and decreased amounts of SPMs in tissue exudates. These findings contribute to our understanding of how MerTK signaling induces 5-LOX–derived SPM biosynthesis and suggest a therapeutic strategy to boost inflammation resolution in settings where defective resolution promotes disease progression.

scholarly journals Platelet aggregation induced by α2-adrenoceptor and protein kinase C activation. A novel synergism

1989 ◽  
Vol 263 (2) ◽  
pp. 377-385 ◽  
Author(s):  
W Siess ◽  
E G Lapetina
Keyword(s):  
Protein Kinase C ◽  
Platelet Aggregation ◽  
Protein Kinase ◽  
Phospholipase C ◽  
Platelet Rich Plasma ◽  
Shape Change ◽  
Protein Activation ◽  
Kinase C ◽  
Gi Protein ◽  
Protein Kinase C Activation

Adrenaline or UK 14304 (a specific alpha 2-adrenoceptor agonist) and phorbol ester (phorbol 12,13-dibutyrate; PdBu) or bioactive diacylglycerols (sn-1,2-dioctanoylglycerol; DiC8) synergistically induced platelet aggregation and ATP secretion. The effect on aggregation was more pronounced than the effect on secretion, and it was observed in aspirinized, platelet-rich plasma or suspensions of washed aspirinized platelets containing ADP scavengers. No prior shape change was found. In the presence of adrenaline, DiC8 induced reversible aggregation and PdBu evoked irreversible aggregation that correlated with the different kinetics of DiC8- and PdBu-induced protein kinase C activation. Adrenaline and UK 14304 did not induce or enhance phosphorylation induced by DiC8 or PdBu of myosin light chain (20 kDa), the substrate of protein kinase C (47 kDa), or a 38 kDa protein. Immunoprecipitation studies using a Gcommon alpha antiserum or a Gi alpha antiserum showed that Gi alpha is not phosphorylated after exposure of platelets to PdBu or PdBu plus adrenaline. Adrenaline, PdBu or adrenaline plus PdBu did not cause stimulation of phospholipase C as reflected in production of [32P]phosphatidic acid. Adrenaline caused a small increase of Ca2+ in the platelet cytosol of platelets loaded with Indo-1; this effect was also observed in the absence of extracellular Ca2+. However, under conditions of maximal aggregation induced by adrenaline plus PdBu, no increase of cytosolic Ca2+ was observed. Platelet aggregation induced by PdBu plus adrenaline was not inhibited by a high intracellular concentration of the calcium chelator Quin-2. These experiments indicate that alpha 2-adrenoceptor agonists, known to interact with Gi, and protein kinase C activators synergistically induced platelet aggregation through a novel mechanism. The synergism occurs distally to Gi protein activation and protein kinase C-dependent protein phosphorylation and does not involve phospholipase C activation or Ca2+ mobilization.

Non-Genomic Effects of Estradiol on Human Platelets: Regulation of Mitogen Activated Protein Kinase Activation and Enhanced Spreading and Aggregation.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2620-2620
Author(s):  
Kadekuzhi V. Vijayan ◽  
Yan Liu ◽  
Tong-Tong Li ◽  
Paul F. Bray
Keyword(s):  
Bone Marrow ◽  
Platelet Aggregation ◽  
Protein Kinase ◽  
Randomized Clinical Trials ◽  
Hormone Replacement ◽  
Cell Types ◽  
Human Platelets ◽  
Mitogen Activated Protein Kinase ◽  
Induce Platelet Aggregation ◽  
Mitogen Activated Protein

Abstract 17β-estradiol or estrogen (E2) is a sex hormone that modulates platelet function and is widely used in hormone replacement therapy (HRT). We and others have previously demonstrated that human megakaryocytes and platelets posses estrogen receptors ERα and ERβ. HRT treatment augmented the bone marrow megakaryocytes without increasing other bone marrow cells, suggesting that E2 can modulate proliferation of megakaryocytes. Since mitogen activated protein kinases (MAPKs) are critical for 1) cell proliferation, 2) megakarytocyte differentiation and proplatelet formation and estrogen activates MAPK in other cell types, we hypothesized that estrogen regulates the activation of MAPK in human platelets. Signaling was studied using washed platelets from male and female subjects in response to varying concentrations of estrogen. Compared to the ethanol (vehicle) treated platelets, 1 nM E2 treated platelets for 60 seconds resulted in an enhanced activation of extracellular signal-regulated kinase 2 (ERK 2) and P38 but not Jun N-kinase (JNK). These results suggest that E2 can cause a non-genomic signaling in human platelets. The MEK inhibitors PD98059 and U0216 blocked the E2 effect, suggesting that the activation of ERK 2 was mediated through the upstream mitogen activated protein kinase kinase (MAPKK). Because E2 can modulate actin reorganization in other cell types and cell spreading is promoted by ERK 2 activation, we examined the effect of E2 on platelet spreading - a process not dependent on agonist stimulation. Compared to ethanol treated platelets, platelets preincubated with 100 nM E2 for 60 seconds and stained with rhodamine phallodine exhibited a ~60 % greater spreading at 5 and 15 minutes. This observation suggests that that E2 can cause rapid actin cytoskeletal reorganization in platelets. Since inhibition of ERK 2 activation blocks aggregation to low doses of thrombin and collagen, we examined a role for E2 in platelet aggregation. E2 alone did not induce platelet aggregation. However, E2 potentiated aggregation with low but not high doses of thrombin and collagen related peptide (CRP) (P=0.05 for 0.02 μg/ml thrombin and P<0.001 for 0.2 μg/ml CRP). Our data demonstrates that E2 can activate MAPK through a non-genomic mechanism and this activation correlates with greater platelet functions like spreading and aggregation. Our findings support a mechanism whereby a consistent non-genomic enhancement of platelet signaling and reactivity by E2 may underlie the increased cardiovascular events observed in recent randomized clinical trials with HRT.

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