Epigenetic differences between naive and primed pluripotent stem cells

It has been 8 years since the concept of naive and primed pluripotent stem cell states was first proposed. Both are states of pluripotency, but exhibit slightly different properties. The naive state represents the cellular state of the preimplantation mouse blastocyst inner cell mass, while the primed state is representative of the post-implantation epiblast cells. These two cell types exhibit clearly distinct developmental potential, as evidenced by the fact that naive cells are able to contribute to blastocyst chimeras, while primed cells cannot. However, the epigenetic differences that underlie the distinct developmental potential of these cell types remain unclear, which is rather surprising given the large amount of active investigation over the years. Elucidating such epigenetic differences should lead to a better understanding of the fundamental properties of these states of pluripotency and the means by which the naive-to-primed transition occurs, which may provide insights into the essence of stem cell commitment.