Abstract:
Background Conversion of Cholesterol to 25-HydroxyCholesterol (25HC) by Cholesterol
25-hydroxylase (CH25H) has been shown to exert broad antiviral properties. Given its
antiviral activities, CH25H is part of an increasingly appreciated connection between type
I interferon (IFN-I) and lipid metabolism. Moreover, the details of this connection appear
to differ in mouse and human cells. Nevertheless, the molecular basis for the induction of
CH25H in humans is not known.
Objective Elucidation of signaling and transcriptional events for induction of CH25H
expression is critical to design therapeutic antiviral agents.
Materials and methods: Wildtype THP-1 monocytic cell-line or THP-1 MyD88 Knockout
cell-line were treated with PMA for 72 hours for differentiation into macrophages.
Differentiated macrophages or Microglial cells were stimulated with either TLR-agonists,
pro-inflammatory cytokine, or interferons, and CH25H mRNAs expression levels were
measured by qPCR.
Results In this study, we show that CH25H is induced by Zika virus infection or TLR
stimulation. Interestingly, CH25H is induced by pro-inflammatory cytokines including 1L-
1, TNF-, and IL-6, and this induction depends on STAT-1 transcription factor.
Additionally, we have observed that ATF3 weakly binds to the CH25H promoter,
suggesting co-operation with STAT-1. However, ZIKV induced CH25H was independent
of type I interferon.
Conclusion This study has demonstrated for the first time that pro-inflammatory
cytokines such as 1L-1, TNF-, and IL-6 induce CH25H expression. Moreover, this
provides further understanding to the connection between innate immunity and sterol
metabolism and encourages the exploration of cytokines in antiviral immunity.
