The sum of many small changes: microRNAs are specifically and potentially globally altered by vitamin D3 metabolites.

Vitamin D3 deficiency is rampant which may contribute to increased risk of many diseases including cancer, cardiovascular disease and autoimmune disorders. Genomic activity of the active metabolite 1,25-dihydroxyvitamin D (1,25D) mediates most vitamin D3's actions and many gene targets of 1,25D have been characterized. As the importance of non-coding RNAs has emerged, the ability of vitamin D3via 1,25D to regulate microRNAs (miRNAs) has been demonstrated in several cancer cell lines, patient tissue and sera. In vitamin D3 intervention patient trials, significant differences in miRNAs are observed between treatment groups and/or between baseline and followup. In patient sera from population studies, specific miRNA differences associate with serum levels of 25D. The findings thus far indicate that dietary vitamin D3 in patients and 1,25D in vitro not only regulate specific miRNA(s), but may also globally upregulate miRNA levels. This article is part of a Special Issue entitled 'Vitamin D Workshop'.