title: Changes in the expression of Hes5 and Mash1 mRNA in the adult rat dentate gyrus after transient forebrain ischemia.
abstract: Accumulating evidence indicates that neurogenesis in the adult brain occurs in restricted brain regions, including the hippocampal dentate gyrus and is promoted by ischemia. The mechanism responsible for ischemia-induced neurogenesis in the adult brain, however, remains unclear. Notch pathway plays a pivotal role in the regulation of the timing for differentiation and determination of the fate of neural progenitor cells in the developing nervous system. To elucidate the mechanism underlying ischemia-induced neurogenesis, we investigated changes in the expression of mRNAs of Hes5, which is a downstream target of Notch, and Mash1, a neurogenic basic helix-loop-helix factor, which is negatively regulated by Hes5, in the adult hippocampal dentate gyrus after transient forebrain ischemia. Transient forebrain ischemia was produced by four-vessel occlusion procedure in rats. The levels of Hes5 mRNA decreased on days 1 and 3 after the start of reperfusion and the decreased levels of the mRNA returned to the basal level by 5 days after ischemia. In contrast, the level of Mash1 mRNA increased on day 1 and then returned to the basal level by 3 days after ischemia. These results suggest that an inhibition of Notch activity and subsequent expression of neurogenic basic helix-loop-helix factors, including Mash1, may, at least in part, contribute to ischemia-induced neurogenesis in the adult dentate gyrus.
authors.affiliation: Department of Molecular and Cellular Pharmacology, Tokyo University of Pharmacy and Life Science, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kawai
authors.forename: Norio
authors.initials: N
authors.lastname: Takagi
authors.forename: Mika
authors.initials: M
authors.lastname: Nakahara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Takeo
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D015152:Blotting, Northern / Q000379:methods; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018891:Dentate Gyrus / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D002546:Ischemic Attack, Transient / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015424:Reperfusion / Q000379:methods; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D012097:Repressor Proteins; D014157:Transcription Factors; C499318:Ascl1 protein, rat; C489686:Hes5 protein, rat