Gene expression of pdgfrb+ cells in the intact and injured spinal cord.

Spinal cord injury (SCI) leads to fibrotic scar formation at the lesion site, which finally affects axon regeneration and motor functional recovery. Myofibroblasts have been regarded as the main cell types that filled in the fibrotic scar, however, the cell source of myofibroblasts in transection and crush SCI model remain to be elusive. Here we used lineage tracing or single cell transcription sequencing to investigate the cell origin of fibrotic scar. We found fibrotic scars were filled from PDGFRß+ daughter cells in spinal cord in crush SCI or transection SCI. The parenchyma perivascular-derived and meninges-derived PDGFRß+ fibroblasts, but not PDGFRß+ pericytes, proliferated and contributed to fibrotic cells in the lesion core. The percentage of meninges-derived fibroblasts specifically was higher than parenchyma perivascular-derived fibroblasts in transection model, which might contribute to the more fibrotic scar in transection model than crush model. These findings may provide theoretical support for the treatment of spinal cord injury. Overall design: Pdgfrb+ cells were isolated from Pdgfrb-CreER::R26-TdT mice by Fluorescence-activated cell sorting (FACS) depending on tdtomato signal.