Vitamin A status significantly alters nuclear factor-κB activity assessed by in vivo imaging

Our study aimed to investigate, in vivo, the relationship between vitamin A status and NF-kappaB activity, a transcription factor central in regulating inflammatory and immune responses. We used a novel transgenic murine NF-kappaB-luciferase reporter model that enabled molecular imaging of NF-kappaB activity in live mice via an intensified image-capture apparatus. Whole-body luminescence, which reflects overall NF-kappaB activity, was elevated 2.2-fold in vitamin A-deficient (VAD) mice compared with control mice. Specifically, NF-kappaB activity in VAD mice was increased 1.8-fold in the lymph nodes and 1.4-fold in the thymus and, NF-kappaB induction in UVB radiation-exposed skin was also enhanced in VAD mice compared with control mice. The administration of all-trans retinoic acid to VAD mice resulted in a transient reduction in NF-kappaB activity and, conversely, a single dose of the RAR-pan-antagonist, AGN 194310, administered to control mice, led to a marked, transient induction of whole-body luminescence. Our results suggest that vitamin A status, and vitamin A itself, affects NF-kappaB activity in vivo and that the elevated NF-kappaB activity in VAD may be a mechanism underlying some of the features of VAD syndrome.