Codelivery of 1α,25-Dihydroxyvitamin D and CYP24A1 Inhibitor VID400 by Nanofiber Dressings Promotes Endogenous Antimicrobial Peptide LL-37 Induction.

Surgical site infections represent a significant clinical problem. Herein, we report a nanofiber dressing for topical codelivery of immunomodulating compounds including 1α,25-dihydroxyvitamin D (1,25(OH)D) and VID400, a inhibitor in a sustained manner, for inducing the expression of the endogenous cathelicidin antimicrobial peptide () gene encoding the hCAP18 protein, which is processed into the LL-37 peptide. Nanofiber wound dressings with coencapsulation of 1,25(OH)D and VID400 were generated by electrospinning. Both 1,25(OH)D and VID400 were coencapsulated into nanofibers with loading efficiencies higher than 90% and exhibited a prolonged release from nanofiber membranes longer than 28 days. Incubation with 1,25(OH)D/VID400-coencapsulated poly(ϵ-caprolactone) nanofiber membranes greatly induced the hCAP18/LL-37 gene expression in monocytes, neutrophils, and keratinocytes in vitro. Moreover, the administration of 1,25(OH)D/VID400-coencapsulated nanofiber membranes dramatically promoted the hCAP18/LL-37 expression in dermal wounds created in both human transgenic mice and human skin tissues. The 1,25(OH)D- and VID400-coencapsulated nanofiber dressings enhanced innate immunity via the more effective induction of antimicrobial peptide than the free drug alone or 1,25(OH)D-loaded nanofibers. Together, 1,25(OH)D/VID400-embedded nanofiber dressings presented in this study show potential in preventing surgical site infections.