Fig. 4

1,25-Hydroxy vitamin D₃ treatment stimulated expression of LL-37 and enhanced antibacterial activity of ASCs. a LL-37 expression. ASCs cultured in the antibiotic-free medium were re-plated in tissue culture-treated 6-well plates (0.5 × 10⁵ cells/2 mL/well) and treated with a range of concentrations of 1,25(OH)₂D₃ (0 to 100 nM) for various time periods (0 to 4 h). At the end of the desired treatment time, the cultures were assayed for LL-37 gene expression by qRT-PCR. Results are expressed as fold increases compared to untreated cultures. Results are derived from 1 to 3 patients (n = 2 to 4) and expressed as mean ± SD. b Antibacterial activity. In another set of experiments, ASC cultures were treated with 100 nM 1,25(OH)₂D₃ for varying time periods, from 0.5 to 6 h, and the culture media were harvested and tested for antibacterial activity by CFU assay. With 1,25(OH)₂D₃ treatment, expression in ASCs was increased in a time- and dose-dependent manner; similarly, upon treatment with 100 nM 1,25(OH)₂D₃, ASC antibacterial activity was also enhanced as a function of time. Results are derived from 1 to 5 patients (n = 4 to 9) and expressed as mean ± SD, except ASCs exposed 1,25(OH)₂D₃ for 6 h (n = 1). ns: no significant. VD3: 1,25(OH)₂D₃