Figure 6. Effect of STX3 knockdown in dHL-60 cells on granule exocytosis. (A) Transfected cells were assessed for degranulation by use of MPO, MMP-9, and albumin ELISA kits after 6 h stimulation by LPS (10 ng/ml). As specific granules are absent from dHL-60 cells, LTF was not detected (n.d.) in the supernatants. Cells transfected with a nonsilencing sequence were used as control. Results are expressed in relative degranulation, meaning the ratio between siRNA STX3 (+LPS/−LPS) and control-transfected cells (+LPS/−LPS) ± sem of at least 3 independent experiments. Significantly different from nonsilencing siRNA: **P < 0.01. (B) Degranulation was determined by measuring the expression of CD markers specific for different types of granules at the plasma membrane by flow cytometry. The relative translocation at the plasma membrane of CD markers for each granule was determined by calculating the ratio between MFI of (+LPS/−LPS) of STX3 siRNA-treated dHL-60 cells and (+LPS/−LPS) of nonsilencing, siRNA-treated dHL-60 cells. Data are given as fold control ± sem of at least 3 independent experiments. Significant differences are indicated as follows: **P < 0.01; ***P < 0.001.