Proteolytic cross-talk: activation of platelet-bound plasminogen by cells bearing uPA (monocytes) or tPA (neurons). Glu-plasminogen (2μM) was bound to platelets as indicated in “Activation of platelet-bound plasminogen by monocytes or neurons.” (A) After treatment with 50 μg/mL CpB, monocytes (●) or neurons (■) were incubated with plasminogen-bearing platelets at various concentrations (0-1.5 106/well) in the presence of 0.75mM CBS0065. The formation of plasmin (mOD/minute) was detected by measuring the release of p-nitroaniline. (Inset) Detection of plasmin formation on platelets (1.8 × 106) in the absence of cells or incubated with monocytes or neurons (105 cells). Results are expressed as the rate of plasmin formation (mean ± SEM; n = 3). (B) After treatment with 50 μg/mL CpB, EMPs were incubated with 5 × 106 platelets bearing plasminogen or with 3nM plasminogen (concentration equivalent to that bound to platelets), or with buffer in the presence of 0.75mM CBS0065. The formation of plasmin (mOD/minute) was detected by measuring the release of p-nitroaniline. Results are expressed as rate of plasmin formation (n = 3). A representative experiment is shown.
