Fig. 1

Cat K-induced human platelet aggregation. Dose-response curve and effect of LWMK, HWMK, and E-64 under cat K activity. The washed human platelets (3.0 x 105/mL) function was measured at baseline and stimulus was added after 30 s. (a) Effect of cat K (20 nM) and papain (1.6 µM) on platelet aggregation. (b) Negative effect of cathepsins L, V, S, and B (at a median effective dose - ED50 - of 0.2 µM) on platelets showing typical tracing results, α-thrombin (1.0 UNIH/500 µL) was used as the agonist control. (c) The bar graph shows percentage of aggregation. Data are presented as means ± SEM (***p<0.0001). Traces show one typical experiment out of at least six. (d) Solutions containing different concentrations of cat K (2.5 to 30 nM) were added to platelets and aggregation was measured as described. Representative traces showing the typical aggregation induced by cat K at different concentrations and α-thrombin (1.0 UNIH/500 µL). (e) Concentration-response bar graph expressed as percentage of aggregation (***p<0.001). (f) Clot aggregate analyses of human platelets treated with cat K (20 nM) and α-thrombin (1.0 UNIH/500 µL). (g) Inhibition of human cat Kactivity (black line) and papain (blue line) on human platelet aggregation by E-64 (5 µM), LWMK (1.0 µM) + HWMK (1.0 µM)