Fig. 4

Schematic view of the putative mechanisms of vitamin D3 action in the brain. Vitamin D3 or its related metabolites and their receptors act via four main regulators: IGF1, ESR1, ERK and NF-κB. Igf1 is underexpressed (green) in both strains while Esr1 is overexpressed in transgenic brains and underexpressed in wild type brains (blue). The expression of Erk and NF-κB is unchanged in both strains but many transcripts under their control are misexpressed in transgenic and wild type animals. Downstream gene regulators include Fos, Stat1 and Stat3. Fos is overexpressed in transgenic animals and underexpressed in wild type animals (blue). Overall, 72 vitamin D-related transcripts are associated to either inflammation (19 genes) or amyloidogenesis and amyloid plaques (29) or AD-related features (24). Sixteen genes are dysregulated in both strains (center areas). However, only three of them - Ace, Igf1 and Gfap - are similarly misexpressed (black colour). Specific up- (red) and down-regulated (green) are indicated for each strain