Long Noncoding RNAs in Pluripotency of Stem Cells and Cell Fate Specification.

Since the annotation of the mouse genome (FANTOM project) [Kawai J et al (2001) Functional annotation of a full-length mouse cDNA collection. Nature 409(6821):685-690] or the human genome [An integrated encyclopedia of DNA elements in the human genome. (2012) Nature 489(7414):57-74; Harrow J et al (2012) GENCODE: the reference human genome annotation for the ENCODE project. Genome Res 22(9):1760-1774], the roles of long noncoding RNAs in coordinating specific signaling pathways have been established in a wide variety of model systems. They have emerged as crucial and key regulators of stem cell maintenance and/or their differentiation into different lineages. In this chapter we have discussed the recently discovered lncRNAs that have been shown to be necessary for the maintenance of pluripotency of both mouse and human ES cells. We have also highlighted the different lncRNAs which are involved in directed differentiation of stem cells into any of the three germ layers. In recent years stem cell therapies including bone marrow transplantation are becoming an integral part of modern medicinal practices. However, there are still several challenges in making stem cell therapy more reproducible so that the success rate reaches a high percentage in the clinic. It is hoped that understanding the molecular mechanisms pertaining to the role of these newly discovered lncRNAs in the differentiation process of stem cells to specific lineages should pave the way to make stem cell therapy and regenerative medicine as a normal clinical practice in the near future.