Platelet-associated IgAs and impaired GPVI responses in platelets lacking WIP

Wiskott-Aldrich Syndrome Protein (WASp) Controls the Delivery of Platelet Transforming Growth Factor-β1

“…Knock-out of platelet WASp and gelsolin expression was verified by immunoblotting as previously described (24,27). Approval for animal research was granted by the Harvard Medical Area Standing Committee, according to National Institutes of Health standards and as outlined in the Institute for Laboratory Animal Research Guide for Care and Use of Laboratory Animals.…”

“…In T-lymphocytes, the formation of critical cell/cell contact points known as immune synapses is contingent on WASp-mediated actin polymeriza-* This work was supported, in whole or in part, by National Institutes of Health tion (21) as is cell polarization and cytokine secretion (22). However, WASp is not required for platelet spreading or its accompanying actin assembly reaction (23), although the hemostatic function in WASp-null mice is reduced because the platelets circulate poorly (24). In light of the emerging role of platelets as cytokine-secreting immune cells (2), we evaluated the role of WASp in regulating TGF-␤1 secretion from platelets.…”

A novel interaction between FlnA and Syk regulates platelet ITAM-mediated receptor signaling and function

“…WT and FlnA-null platelets were treated with PMA, which activates protein kinase C directly, and analyzed by flow cytometry for P-selectin (CD62P) expression, as a marker for -granule secretion, or fibrinogen binding, as a marker for integrin IIb3 activation (Falet et al, 2009). FlnA-null platelets expressed P-selectin and bound fibrinogen normally in response to PMA (Fig.…”

“…Washed platelets were fixed and permeabilized in Cytofix/ Cytoperm solution (BD), washed in Perm/Wash solution (BD), and incubated with a rabbit anti-FlnA antibody or a rabbit anti-FlnB antibody, followed by Alexa Fluor 488-labeled donkey anti-rabbit IgG antibody. For the actin assembly assay, resting or activated, fixed, and permeabilized platelets were incubated with 2 µM TRITC-labeled phalloidin (Falet et al, 2009).…”

“…Blood was collected from mice by retroorbital plexus bleeding in EDTA. Peripheral blood platelet count was performed using an ADVIA 120/2120 automated hematology analyzer (Bayer HealthCare; Falet et al, 2009).…”