Transient activation of Notch signaling in the injured adult brain.
Brain injury induces various kinds of cellular responses that lead to tissue regeneration and repair. Recent studies have demonstrated that resident progenitors proliferate and then differentiate into mature neuronal cells. We show here that proliferating cells in the cryo-injured cerebral cortex transiently expressed Notch1 immunoreactivity in their cytoplasm. Since activated Notch signaling regulates cellular fate in the developing nervous system, similar regulation may exist in the injured adult brain. To monitor the Notch signaling pathway, we examined whether components of the signaling pathway were co-expressed in Notch1-positive cells. Presenilin-1, a membrane-spanning protease that is required for the release of the Notch intracellular domain, was detected in the Notch1-positive cells and Hes1, a target of the Notch intracellular domain, also co-localized with Notch1 three days after cryo-injury. These results suggest that transient activity of the Notch signaling pathway is involved in the regulation of proliferation and differentiation of progenitors in the injured brain.
Tatsumi
Kouko
K
The Department of Anatomy, Faculty of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521, Japan. tkouko@naramed-u.ac.jp
Okuda
Hiroaki
H
Makinodan
Manabu
M
Yamauchi
Takahira
T
Makinodan
Eri
E
Matsuyoshi
Hiroko
H
Manabe
Takayuki
T
Wanaka
Akio
A
D000818:Animals; D001930:Brain Injuries / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D005260:Female; D007150:Immunohistochemistry; D051379:Mice; D008813:Mice, Inbred ICR; D018613:Microscopy, Confocal; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism
D051880:Receptors, Notch