Retinal Ganglion Cell Expression of Cytokine Enhances Occupancy of NG2 Cell-Derived Astrocytes at the Nerve Injury Site: Implication for Axon Regeneration

ABSTRACT: Following injuryin the central nervous system, a population of astrocytes occupy the lesion site, form glial bridges and facilitate axon regeneration. Theseastrocytes originate primarily from resident astrocytes orNG2+ oligodendrocyteprogenitor cells. However, theextentto which these cell types give rise to the lesion-filling astrocytes,andwhethertheastrocytes derived from differentcell typescontribute similarly to optic nerve regenerationremain unclear.Here we examine the distributionof astrocytes and NG2+ cellsin an optic nerve crush model.Weshow that optic nerve astrocytes partially fill the injury site over timeafter a crush injury.Viral mediated expression of a growth-promotingfactor,ciliary neurotrophic factor (CNTF),in retinal ganglion cells (RGCs) promotesaxon regeneration without altering the lesion size or the degreeof lesion-filling GFAP+ cells. Strikingly, using inducible NG2Cre driver mice, wefoundthat CNTF overexpression in RGCs increasesthe occupancy ofNG2+ cell-derived astrocytes in the optic nerve lesion. An EdU pulse-chase experiment showsthat the increase in NG2 cell-derived astrocytes is not due to an increase in cell proliferation.Lastly, we performedRNA-sequencing on the injured optic nerve and reveal that CNTF overexpression in RGCs results in significant changes in the expression of distinct genes,including those that encode chemokines, growth factor receptors,and immune cell modulators.Even though CNTF-induced axon regeneration has long been recognized, this is the first evidence of this procedure affecting glial cell fate at the optic nerve crush site.We discuss possible implication of theseresultsforaxon regeneration.

ORGANISM(S): Mus musculus

PROVIDER: GSE196824 | GEO | 2022/06/24

REPOSITORIES: GEO