Fig 1: Platelets secreted large amounts of DCD, a previously unknown component of platelets, after co-culture with MRSA. (A) Immunofluorescence detection of DCD in platelets. Phalloidin (green): CoraLite488 conjugated phalloidin, CL488-Phalloidin served as the counterstain, at dilution of 1: 100; DCD (red): Dermcidin. Scale bar = 500 µm. Images are representative of three independent experiments. (B) DCD expression detection in platelet lysates by western blot, 10, 15, and 20 µg, respectively, represents the added protein content of each well after platelet lysis. (C) Measurement of DCD content in the supernatant of platelets co-cultured with or without MRSA by ELISA. All results have been tested at least three times. Data presented as mean ± SEM. Student’s T test for two-group comparisons.
Fig 2: DCD promoted the inhibitory effect of platelets against MRSA. (A) Bacterial colonies using plates. Adding different concentrations of DCD-1L to the bacterial suspension after platelet co-culture with MRSA for 10 h. Then, the bacterial colonies were counted on plates after DCD-1L incubated with the bacterial suspension for 4 h. Images are representative of three independent experiments. (B) Bacterial mortality curve according to the results of (A). P: platelet; P-M: platelets co-culture with MRSA; P-M + DCD-1L (20, 25, and 30 µg/mL): adding DCD-1L at concentrations of 20, 25, and 30 µg/mL, respectively, to the bacterial solution after platelets co-culture with MRSA for 10 h. (C) Bacterial fluid turbidity of each group. DCD-1L at a concentration of 30 µg/mL was added to the co-culture system of platelets and MRSA. After co-culture for 10 h, the turbidity of the bacterial suspension was compared, and the number of bacterial colonies was counted in each group. This figure is representative of three independent experiments. (D) Bacterial colony counts of each group in (C). MRSA: MRSA culture alone; P-M: platelets co-culture with MRSA; P-M +DCD-1L: adding DCD-1L (30 µg/mL) to the co-culture system of platelets and MRSA and then co-culture for 10 h. All results have been tested at least three times. Data presented as mean ± SEM. Student’s t test for two-group comparisons.
Fig 3: Antimicrobial activity of DCD-1L against MRSA. MRSA (106 CFU/mL) was co-cultured with different concentrations of DCD-1L (0, 5, 10, 15, 20, 25, 30, 35, and 40 µg/mL) for 4 h, and then, the bacterial colony counts were counted by plates. (A) Bacteria count by plates. Images are representative of three independent experiments. (B) Bacterial mortality curve according to the results of (A). DCD-1L, Dermcidin-1L. All results have been tested at least three times. Data presented as mean ± SEM.
Fig 4: DCD is present in the α-granules of platelets. (A) Observation of DCD in platelets by confocal microscopy. Phalloidin (green): CoraLite488 conjugated phalloidin, CL488-Phalloidin served as the counterstain, at dilution of 1:100; DCD (red): dermcidin. Scale bar = 10 µm. (B) Representative IEM image for the location of DCD in platelets. DCD is labeled with black gold beads (Red arrows indicate). Scale bar = 1.0 µm (left panel), 500 nm (right and below panels). The original magnification was 70,000× (left panel) and 210,000× (right and below panels). The panels in Fig. 4 are representative of three independent experiments.
from Biorbyt for Human Dermcidin ELISA Kit
Application Notes: Detection Wavelength: 450 nm