In vitro aggregation and integrin αIIbβ3 activation of platelets from Ptpn11^D61G/+ mice.Ptpn11^D61G/+ platelets were stimulated with CRP (0.5 and 1 μg/mL), collagen (0.5 and 1 μg/mL), or CLEC-2 antibody (Ab) (5 and 10 μg/mL) (A) or with TXA2 analog (U46619) (0.1 μM) or thrombin (0.1 U/mL) (B). Representative aggregation curves are shown. Percentage of maximal aggregation at different times and area under curve (AUC) were measured (mean ± SEM; n = 5). (C) Anticoagulated mice whole blood, where platelets were labeled with DiOC₆, was perfused through Cellix Vena8 Fluoro+ biochips at arteriolar physiological shear rate of 1500 s⁻¹ on VWF matrix over 2 minutes to analyze platelet rolling. Platelet firm adhesion was measured over 2 minutes after capillary wash. Platelet adhesion was visualized in real time by videomicroscopy (scale bar, 20 μm). Profiles shown are representative of 4 WT mice and 4 Ptpn11^D61G/+ mice. Surface covered by platelets was quantified by using ImageJ software (mean ± SEM). (D) JON/A-phycoerythrin Ab binding to resting or stimulated platelets with CRP (0.5 and 1 μg/mL) was analyzed by flow cytometry. Graph represents mean ± SEM of mean fluorescence intensity (n = 6 mice of each genotype). (E) Washed platelets were allowed to spread on a fibrinogen-coated surface over 20 minutes in presence or not of CRP (1 µg/mL). Platelet surface was measured by using ImageJ software. Representative confocal images are shown (scale bar, 10 µm). Graph represents mean ± SEM (n = 30 platelets from 3 mice per genotype). *P < .05, **P < .01, ***P < .001 vs WT; ††P < .01 according to 2-way ANOVA; †††P < .001 according to 1-way ANOVA.