Ubiquitously expressed Human Beta Defensin 1 (hBD1) forms bacteria-entrapping nets in a redox dependent mode of action
Fig 2
Characterization of the hBD1red target in bacterial compartments.
(A) Transcription activity of the B. subtilis ypuA promoter indicative of cell envelope damage. Bacteria were incubated with increasing concentrations of hBD1ox and hBD1red. (B) Membrane leakage as a result of hBD1 treatment was determined by quantifying carboxyfluorescein efflux from liposomes POPC/cholesterol (3:2 molar ratio, a human membrane model) or an E. coli polar lipid extract. Presented is the leakage level reached after 45 min incubation with mean and standard deviations from triplicates. Permeabilization, by hBD1red on E. coli liposomes, was significantly higher than by hBD1ox (***p<0.001 only for 1 μM). (C) Membrane depolarization of 1.5 x 106 CFU E. coli MC1000 in response to hBD1. 1 h treatment was analyzed by flow cytometry. Positive control (+) was incubated with hBD3ox (50 μg/ml) and the negative control (-) without any peptide. The statistic was evaluated by using student’s t-test with **p = 0.0072. Data are presented as mean +/- SEM of at least three independent experiments.