An ependymal cell census identifies heterogeneous and ongoing cell maturation in the adult mouse spinal cord that changes dynamically on injury

The adult spinal cord stem cell potential resides within the ependymal cell population and declines with age. Ependymal cells are, however, heterogeneous, and the biological diversity this represents and how it changes with age remain unknown. Here, we present a single-cell transcriptomic census of spinal cord ependymal cells from adult and aged mice, identifying not only all known ependymal cell subtypes but also immature as well as mature cell states. By comparing transcriptomes of spinal cord and brain ependymal cells, which lack stem cell abilities, we identify immature cells as potential spinal cord stem cells. Following spinal cord injury, these cells re-enter the cell cycle, which is accompanied by a short-lived reversal of ependymal cell maturation. We further analyze ependymal cells in the human spinal cord and identify widespread cell maturation and altered cell identities. This in-depth characterization of spinal cord ependymal cells provides insight into their biology and informs strategies for spinal cord repair. [Display omitted] •Single-cell transcriptomic profiling of adult mouse spinal cord ependymal cells•Identification of immature ependymal cells as potential spinal cord stem cells•Spinal cord injury induces transient reversal of cell maturation•Ependymal cell identities in the adult spinal cord differ between mice and humans Rodrigo Albors et al. profile the heterogeneous population of ependymal cells in the adult mouse spinal cord. Computationally and using spinal cord injury assays, they identify immature cells as potential spinal cord stem cells and uncover widespread cell maturation and altered cell identities in the human adult spinal cord.