Intracellular signaling similarity reveals neural stem cell‐like properties of ependymal cells in the adult rat spinal cord

<jats:p>Proliferation of ependymal cells of the adult spinal cord (<jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells) in the intact condition has been considered as a quite rare event. To visualize proliferating/proliferated <jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells, we used the intensive 5‐bromo‐2′‐deoxyuridine (BrdU) administration method to find that about two cells in the ependymal layer incorporated BrdU in a 10‐μm‐thick section. Because these two cells were not considered to undergo further proliferation, we analyzed the positioning and motility of two neighboring BrdU‐incorporated proliferated cells and elucidated the tendency of the movement of <jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells to the outer side inside the ependymal layer. Even if it was rare, one of the proliferated cells in the ependymal layer differentiated into astrocytes. Gene introduction of Notch intracellular domain (<jats:styled-content style="fixed-case">NICD</jats:styled-content>), a constitutively active form of Notch1, into <jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells demonstrated both increase in proliferation and induction of differentiation into astrocytes. Overexpression of Sox2 promoted proliferation in <jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells. The reaction of gene introduction of <jats:styled-content style="fixed-case">NICD</jats:styled-content> and Sox2 indicates the similarity of intracellular signaling between <jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells and neural stem cells. Also, considering the fact that <jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells express these two factors in the intact condition, Notch and Sox2 are important for the cell fate control of <jats:styled-content style="fixed-case">SCE</jats:styled-content>p cells in the intact condition.</jats:p>