In vivo response of the human epigenome to vitamin D: A Proof-of-principle study

Abstract In vitro cell culture studies showed that the hormonal form of vitamin D 3 , 1α,25-dihydroxyvitamin D 3 , significantly (p  3 . Blood samples were taken directly before each supplementation as well as one and two days after, chromatin was isolated from peripheral blood mononuclear cells without any further in vitro culture and at all nine time points epigenome-wide chromatin accessibility was assessed by applying FAIRE-seq (formaldehyde-assisted isolation of regulatory elements sequencing). The vitamin D 3 bolus resulted in an average raise in 25-hydroxyvitamin D 3 (25(OH)D 3 ) serum concentration of 11.9 and 19.4 nM within one and two days, respectively. Consistently accessible chromatin was detected at 5205 genomic loci, the 853 most prominent of which a self-organizing map algorithm classified into early, delayed and non-responding genomic regions: 70 loci showed already after one day and 361 sites after two days significant (p  in vivo conditions a rather minor rise in 25(OH)D 3 serum levels is sufficient to result in significant changes at hundreds of sites within the epigenome of human leukocytes.