Abstract
Vitamin D has a wide range of biological functions from helping the body control calcium and phosphate levels, to the formation and maintenance of bone and hair, immunomodulation, and proper barrier response. In turn, defects in vitamin D receptor signaling or vitamin D status can lead to numerous clinical disorders such as osteomalacia, alopecia, increased cancer prevalence, and compromised immune and wound repair responses. In recent years it has become evident that microRNAs (miRNAs) are important mediators of vitamin D signaling. miRNAs are small noncoding RNAs that orchestrate dynamic posttranscriptional regulatory networks. Not only do miRNAs impact vitamin D signaling but vitamin D also regulates miRNA networks during homeostasis and disease across species. Although improved methods have identified a diverse set of miRNAs that provide a better understanding of genome regulation, the ultimate goal is to go beyond profiling toward miRNA-based transformative clinical applications for vitamin D-regulated disorders and conditions. In this chapter we acknowledge and discuss the dynamic and emerging interactions between miRNAs and the vitamin D signaling system.