title: NG2 cells are not a major source of reactive astrocytes after neocortical stab wound injury.
abstract: NG2 cells are an abundant glial cell type in the adult brain. They are distinct from astrocytes, mature oligodendrocytes, and microglia. NG2 cells generate oligodendrocytes and a subpopulation of protoplasmic astrocytes in the ventral forebrain during development. To determine whether NG2 cells generate reactive astrocytes in the lesioned brain, stab wound injury was created in adult NG2creBAC:ZEG double transgenic mice, in which enhanced green fluorescent protein (EGFP) is expressed in NG2 cells and their progeny, and the phenotype of the EGFP(+) cells was analyzed at 10 and 30 days post lesion (dpl). The majority (>90%) of the reactive astrocytes surrounding the lesion that expressed glial fibrillary acidic protein (GFAP) lacked EGFP expression, and conversely the majority (>90%) of EGFP(+) cells were GFAP-negative. However, 8% of EGFP(+) cells co-expressed GFAP at 10 dpl. Most of these EGFP(+) GFAP(+) cells were morphologically distinct from hypertrophic reactive astrocytes and exhibited weak GFAP expression. NG2 was detected in a fraction of the EGFP(+) GFAP(+) cells found at 10 dpl. By 30 dpl the number of EGFP(+) GFAP(+) cells had decreased more than four-fold from 10 dpl. A similar transient appearance of EGFP(+) GFAP(+) cells with simple morphology was observed in NG2creER™:ZEG double transgenic mice in which EGFP expression had been induced in NG2 cells prior to injury. NG2 cell-specific deletion of the oligodendrocyte lineage transcription factor Olig2 using NG2creER™:Olig2(fl/fl) :ZEG triple transgenic mice did not increase the number of EGFP(+) reactive astrocytes. These findings suggest that NG2 cells are not a major source of reactive astrocytes in the neocortex.
authors.affiliation: Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA.
authors.forename: Mila
authors.initials: M
authors.lastname: Komitova
authors.forename: David R
authors.initials: DR
authors.lastname: Serwanski
authors.forename: Q Richard
authors.initials: QR
authors.lastname: Lu
authors.forename: Akiko
authors.initials: A
authors.lastname: Nishiyama
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology* / Q000378:metabolism; D001930:Brain Injuries / Q000378:metabolism; D002452:Cell Count; D002454:Cell Differentiation / Q000502:physiology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry; D051379:Mice; D008822:Mice, Transgenic; D019579:Neocortex / Q000166:cytology / Q000293:injuries* / Q000378:metabolism; D009457:Neuroglia / Q000166:cytology* / Q000378:metabolism; D014951:Wounds, Stab / Q000378:metabolism
chemical_list: D005904:Glial Fibrillary Acidic Protein