Glial progenitor heterogeneity, key regulators and cell signaling revealed by single-cell RNA-sequencing provide insights to regeneration in spinal cord injury

Recent studies in brain and spinal cord have revealed the heterogenous nature of astrocytes; however, how diverse constituents of astrocyte lineage cells are regulated in adult spinal cord after injury and contribute to regeneration remains elusive. We performed single-cell RNA-sequencing (scRNA-seq) of astrocyte lineage cells from sub-chronic spinal cord injury (SCI) models, identified and compared with the subpopulations in the acute stage data. We found the subpopulations with distinct functional enrichment and their identities defined by subpopulation-specific transcription factors and regulons. Our analyses revealed the molecular signature, location and morphologies of potential residential neural progenitors or neural stem cells in the adult spinal cord before and after injury, and the intermediate cells enriched in neuronal markers that could potentially transition into other subpopulations. The investigation of stage-specific cell-cell communications among astrocyte lineage cells and with other cell types in the tissue generated valuable insight into signaling pathway networks in SCI. This study has significantly expanded the knowledge of the heterogeneity and cell state transition of glial progenitors in adult spinal cord before and after injury. Overall design: We performed single-cell RNA-sequencing (scRNA-seq) of astrocyte lineage cells from sub-chronic spinal cord injury (SCI) models, identified and compared with the subpopulations in the acute stage data.