MicroRNAs: Modulators of Tooth Development.

MicroRNAs (miRNAs) are non-coding RNAs that are involved in various biological pathways by regulating gene expression. Teeth develop via reciprocal and sequential interactions between the epithelium and the ectomesenchyme. The speci.c functions of several genes during tooth development are known, and the involvement of their mutations in the pathogenesis of congenital dental defects has been widely studied. The miRNA pathway is considered to have a significant role in embryogenesis including tooth development. It has been shown that miRNAs regulate morphogenesis of tooth by fine-tuning the signalling networks, however, their precise role in tooth differentiation and morphogenesis is still elusive. The present review focuses on the studies that have used animal models to explore the function of miRNAs in tooth development. Major findings with special emphasis on the miRNA involvement in .ne-tuning and network regulation are presented and discussed. Disturbances in tooth development in the global miRNA processing knockouts mirror the essential fine-tuning guiding appropriate formation of dental hard tissues. However, further investigation of single miRNA function and mutation, including deletion and overexpression, may lead to improved knowledge on development of particular dental defects in humans. In the light of similarities between tooth development and other organs originating from the epithelium, further understanding of miRNAs` function during tooth development may have wide biological relevance.