%0 Journal Article %1 siauw_group_2006 %A Siauw, Celine %A Kobsar, Anna %A Dornieden, Catharina %A Beyrich, Claudia %A Schinke, Birgitta %A Schubert-Unkmeir, Alexandra %A Abele-Horn, Marianne %A Speer, Christian P %A Eigenthaler, Martin %D 2006 %J Thrombosis and Haemostasis %K Activation, Adhesion, Adhesiveness, Bacterial Blood Cells, Cultured, Fibrinogen, Humans, Infant, Newborn, Platelet Platelets, Receptors, Sepsis, Signal Streptococcus Transduction, ag_horn ag_unkmeir agalactiae {IgG,} %N 5 %P 836--849 %T Group B streptococcus isolates from septic patients and healthy carriers differentially activate platelet signaling cascades %U http://www.ncbi.nlm.nih.gov/pubmed/16676076 %V 95 %X Infection 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 for a 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 FcgammaRIIA receptor signaling pathways including phospholipase C gamma2 (PLCgamma2), 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 FcgammaRIIA-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 FcgammaRIIA 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.

@article{siauw_group_2006, abstract = {Infection 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 for a 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 {FcgammaRIIA} receptor signaling pathways including phospholipase C gamma2 {(PLCgamma2),} 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 {FcgammaRIIA-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 {FcgammaRIIA} 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.}, added-at = {2011-04-07T15:44:20.000+0200}, author = {Siauw, Celine and Kobsar, Anna and Dornieden, Catharina and Beyrich, Claudia and Schinke, Birgitta and {Schubert-Unkmeir}, Alexandra and {Abele-Horn}, Marianne and Speer, Christian P and Eigenthaler, Martin}, biburl = {https://www.bibsonomy.org/bibtex/2901890fc73b2262b913fb9f33401c1de/hymi}, interhash = {ce9db5d12c7aa10d0b61d5456588519f}, intrahash = {901890fc73b2262b913fb9f33401c1de}, issn = {0340-6245}, journal = {Thrombosis and Haemostasis}, keywords = {Activation, Adhesion, Adhesiveness, Bacterial Blood Cells, Cultured, Fibrinogen, Humans, Infant, Newborn, Platelet Platelets, Receptors, Sepsis, Signal Streptococcus Transduction, ag_horn ag_unkmeir agalactiae {IgG,}}, month = may, note = {{PMID:} 16676076}, number = 5, pages = {836--849}, timestamp = {2011-04-07T16:38:32.000+0200}, title = {Group B streptococcus isolates from septic patients and healthy carriers differentially activate platelet signaling cascades}, url = {http://www.ncbi.nlm.nih.gov/pubmed/16676076}, volume = 95, year = 2006 }