Table 1.
MBCs of Synthetic AMPs and Conventional Agents against Acne-Inducing Propionibacterium acnes.
Fig 1.
Morphological perturbations and blebs induced in P. acnes by P5.
Shown are P. acnes cells after incubation for 20 min in the absence (A) and presence of CA-MA (B), P5 (C) and P4 (D) at a concentration of 1/2 MBC. Arrows point to morphological perturbations and blebs, which were clearly visible following treatment with P5.
Fig 2.
P5 inhibits expression of IL-8 and TNF-α mRNA induced by P. acnes infection in HKs.
Total RNA was collected from P. acnes-infected HKs with and without P5 treatment. Expression of IL-8 (A) and TNF-α (B) mRNA was measured using quantitative RT-PCR with human IL-8- and TNF-α-specific primers. The relative level of each mRNA was normalized to the expression of 18S rRNA. All data were compared to the untreated control values. The data shown are representative of triplicate experiments. All values are expressed as the mean ± SD. *p<0.001.
Fig 3.
P. acnes-induced secretion of IL-8 and TNF-α from HKs was inhibited by P5 treatment.
IL-8 (A) and TNF-α (B) were measured in culture supernatants after incubating P. acnes-infected HK cells for 24 h in the presence or absence of 1.6 μM P5, P4 or CA-MA. The data shown are representative of triplicate experiments. All values are expressed as mean ± SD. *p< 0.001.
Fig 4.
P5 inhibits expression of TLR2 induced by P. acnes in HKs.
(A) Expression of TLR2 mRNA was measured using real-time RT-PCR and normalized to the expression of 18S rRNA. All values are expressed as the mean ± SD. *P<0.001. (B) Immunofluorescent localization of TLR2 within HKs. P. acnes-infected HKs were incubated for 24 h in the presence or absence of 1.6 μM P5 or P4, after which the distribution of TLR2 was determined by immunofluorescent labeling. FITC-labeled TLR2 is shown in green, while the Hoechst-stained nuclei are blue: (a) treated with PBS; (b) treated with P. acnes; (c) treated with P. acnes plus P5; (d) treated with P. acnes plus P4; (e) treated with P5 alone.
Fig 5.
P5 inhibits NF-κB nuclear translocation in P. acnes-infected HK cells.
The intracellular distribution of NF-κB was determined by immunofluorescent labeling of NF-κB p65 (green), while nuclei were Hoechst stained (blue): (A) untreated HK cells; (B) HK cells treated with P. acnes; (C) HK cells treated with P. acnes plus P5; HK cells treated with P. acnes plus P4 (D).
Fig 6.
P5 inhibits P. acnes-induced intracellular Ca2+ mobilization in HK cells.
Fura-2-loaded HKs on glass coverslips were treated with P. acnes (1 x 108 CFU/150 μl) in the presence or absence of 0.8 μM P5 or P4. Uninfected HKs treated with P5 and P4 served as negative controls. The intracellular free Ca2+ concentration was determined by measuring the ratio of fura-2 fluorescence at 510 nm elicited by excitation at 340 and 380 nm. The peaks in this figure represent the simultaneous intracellular Ca2+ responses of different cells to P. acnes or the indicated AMP.
Fig 7.
Effects of intradermal injection of P5 on P. acnes cell growth and P. acnes-induced inflammation in ICR mice.
(A) Inflammation-associated erythema was visualized 24 h after injection of live P. acnes (1x108 CFU/20 μl in PBS), P. acnes plus P5 (1.6 μM) or P5 alone into the ears of ICR mice. (B) Percent differences (right vs. left (control) ear) in ear edema compared among treatment groups every 24 h for 96 h. (C) Total number of P. acnes (CFUs) recovered from the ears of mice in the indicated treatment groups. All values represent mean ± SD of three individual experiments (*P<0.001). Untreated, uninfected ears served as a negative control.
Fig 8.
Schematic diagram of P5 based on the toll-like receptor-mediated immune response against P. acnes.
Schematic diagram illustrating the proposed mechanism by which P5 suppresses P. acnes-induced inflammatory responses within acne lesions by disrupting TLR2-to-NF-κB signaling.