Figure 2 | Scientific Reports

Figure 2

From: Phenol-soluble modulin α4 mediates Staphylococcus aureus-associated vascular leakage by stimulating heparin-binding protein release from neutrophils

Figure 2

PSMα4 stimulates primary granule exocytosis, which is free of the blocking effect of serum lipoprotein.

(A) Synthetic PSMα4 appeared to be less cytotoxic than PSMα1–3. Cytotoxicity of PSMα1–4 on PMNs was evaluated LDH test. PMNs were incubated with PSMα1–3 at 10 μg/mL, PSMα4 at 10, 20, 50, or 100 μg/mL at 37 °C for 30 min. The control peptide was added at 10 μg/mL. (B) Human serum (10%) significantly reduced PSMα1–3-induced HBP release from PMNs but did not affect PSMα4-induced HBP release from PMNs. (C) Serum significantly reduced PSMα1–3-induced PMN lysis but had no effects on PSMα4-induced PMN lysis. (D) PSMα4 peptide (10 μg/mL) increased MPO release from whole blood. (E) PSMα4 peptide (10 μg/mL) increased elastase release from whole blood. MPO and elastase in the supernatant were analyzed by ELISA. (F) PSMα4-induced cell surface expression of CD63 was not affected by human serum (10%). PMNs were incubated with PSMα4 peptides (10 μg/mL) with 10% human serum at 37 °C for 30 min. The PMNs were stained with PE-labeled anti-CD63 antibody (1:100 dilution) and 5 μM DRAQ5. ***P < 0.001, **P < 0.01, *P < 0.05.

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