CD148 is essential for αIIbβ3-mediated platelet spreading. (Ai) Washed platelets (2 × 107/mL) from wild-type (WT) and CD148 transmembrane-knockout (KO) mice were treated with 10 μM indomethacin and 2 U/mL apyrase in the absence (basal) and presence of either 10 μM PP1 or 1 U/mL thrombin before being placed on a fibrinogen-coated surface for 45 minutes. Platelets were fixed and images captured by differential interference contrast (DIC) microscopy (5 μm scale bar). (Aii) Surface areas of platelets per condition shown in (Ai) were measured using ImageJ software (mean ± SEM; n = 250-500 individual platelets per condition). (Bi) Representative DIC images of WT and KO platelets captured in real time at 0, 5, 10, 15, and 20 minutes (min) after being placed on a fibrinogen-coated surface, in the presence of 10 μM indomethacin and 2 U/mL apyrase. (Bii) Surface areas of individual platelets were measured at various time points during spreading on fibrinogen using ImageJ software (mean ± SEM; n = 6-10 platelets per time point). P value was calculated by 2-way analysis of variance. Results are representative of 3 WT and 3 KO mice. See also Figure S4 Videos S1,S2.
