Genetic fate mapping of Olig2 progenitors in the injured adult cerebral cortex reveals preferential differentiation into astrocytes.
Olig2 is a basic helix-loop-helix (bHLH) transcription factor essential for development of motoneurons and oligodendrocytes. It is known that Olig2(+) cells persist in the central nervous system (CNS) from embryonic to adult stages and that the number of Olig2(+) progenitors increases in the injured adult CNS. Recent studies have demonstrated an inhibitory action of Olig2 on neurogenesis in adult CNS, but the fate of Olig2(+) cells in the injured state remains largely unknown. To trace directly the fate of Olig2 cells in the adult cerebral cortex after injury, we employed the CreER/loxP system to target the olig2 locus. In this genetic tracing study, green fluorescent protein (GFP) reporter-positive cells labeled after cryoinjury coexpressed glial fibrillary acidic protein (GFAP), an astrocytic marker. Electron microscopy also showed that GFP(+) cells have the ultrastructural characteristics of astrocytes. Furthermore, GFP(+) cells labeled before injury, most of which had been NG2 cells, also produced bushy astrocytes. Here we show direct evidence that Olig2(+) cells preferentially differentiate into astrocytes, which strongly express GFAP, in response to injury in the adult cerebral cortex. These results suggest that reactive astrocytes, known to be the main contributors to glial scars, originate, at least in part, from Olig2(+) cells.
Tatsumi
Kouko
K
The Department of Anatomy, Faculty of Medicine, Nara Medical University, Nara, Japan. tkouko@naramed-u.ac.jp
Takebayashi
Hirohide
H
Manabe
Takayuki
T
Tanaka
Kenji F
KF
Makinodan
Manabu
M
Yamauchi
Takahira
T
Makinodan
Eri
E
Matsuyoshi
Hiroko
H
Okuda
Hiroaki
H
Ikenaka
Kazuhiro
K
Wanaka
Akio
A
D000818:Animals; D000941:Antigens / Q000378:metabolism; D001253:Astrocytes / Q000378:metabolism* / Q000648:ultrastructure; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D015415:Biomarkers / Q000032:analysis / Q000378:metabolism; D001930:Brain Injuries / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D002454:Cell Differentiation / Q000235:genetics; D019070:Cell Lineage / Q000235:genetics*; D002874:Chromosome Mapping / Q000379:methods; D002921:Cicatrix / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D003452:Cryosurgery / Q000379:methods; D055879:Gene Knock-In Techniques; D017930:Genes, Reporter / Q000235:genetics; D005904:Glial Fibrillary Acidic Protein / Q000235:genetics / Q000378:metabolism; D005911:Gliosis / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D049452:Green Fluorescent Proteins / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D046529:Microscopy, Electron, Transmission; D009419:Nerve Tissue Proteins / Q000235:genetics*; D000076104:Oligodendrocyte Transcription Factor 2; D011509:Proteoglycans / Q000378:metabolism; D013234:Stem Cells / Q000378:metabolism* / Q000648:ultrastructure; D000099216:Chondroitin Sulfate Proteoglycan 4
D000941:Antigens; D051792:Basic Helix-Loop-Helix Proteins; D015415:Biomarkers; D005904:Glial Fibrillary Acidic Protein; D049452:Green Fluorescent Proteins; D009419:Nerve Tissue Proteins; D000076104:Oligodendrocyte Transcription Factor 2; D011509:Proteoglycans; D000099216:Chondroitin Sulfate Proteoglycan 4; C512773:Olig2 protein, mouse