Astrocytes Originated from Neural Stem Cells Drive Regenerative Remodeling of Pathologic CSPGs in Spinal Cord Injury

Neural degeneration is a hallmark of spinal cord injury (SCI). Multipotent neural precursor cells (NPCs) have the potential to reconstruct the damaged neuron-glia network due to their tri-lineage capacity to generate neurons, astrocytes and oligodendrocytes. However, astrogenesis is the predominant fate of resident or transplanted NPCs in the SCI milieu adding to the abundant number of residents astrocytes in the lesion. How NPC-derived astrocytes respond to the inflammatory milieu of SCI, and the mechanisms by which they contribute to the post-injury recovery processes remain largely unknown. Here, we uncover that activated NPC-derived astrocytes exhibit distinct molecular signature that is immune modulatory and foster neurogenesis, neuronal maturity and synaptogenesis. Mechanistically, NPC-derived astrocytes perform regenerative matrix remodeling by clearing the inhibitory chondroitin sulfate proteoglycans (CSPGs) from the injury milieu through LAR and PTP- receptor mediated endocytosis and production of ADAMTS1 and ADAMTS9, while most resident astrocytes are pro-inflammatory and contribute to pathologic deposition of CSPGs. These novel findings unravel critical mechanisms of NPC-mediated astrogenesis in SCI repair.