Vitamin D3 and phenylbutyrate promote development of a human dendritic cell subset displaying enhanced antimicrobial properties

A promising strategy in the fight against multidrug-resistant pathogens is the induction of endogenous AMPs, with compounds such as VitD(3) and PBA. These compounds display an array of immunomodulatory effects that remain to be investigated in further detail to establish their role in the clearance of infection and possible modulation of AMP expression. Here, we have investigated the effects of VitD(3) and PBA on human monocyte-DC differentiation and found that VitD(3) and PBA promote the development of a stretched CD14(+)/CD1a(-) DC subset. This subset produced enhanced levels of ROS and human cathelicidin; furthermore, it displayed enhanced killing capacity of Staphylococcus aureus compared with control DCs. When experiments were performed in WT and cathelicidin-deficient mice, we established that a ROS-producing, stretched DC subset was also induced in mouse-derived cells, independent of cathelicidin expression. However, in contrast to the human DCs, enhanced cathelicidin expression and enhanced antimicrobial activities were not found in the murine VitD(3)/PBA DC subset. In conclusion, the results of this study show that VitD(3) and PBA induce a human DC subset that is effective against infection. These results promote further research into the use of these compounds as an antimicrobial treatment strategy.