Characterization of side population (SP) cells in murine cochlear nucleus.
CONCLUSIONS
We characterized side population (SP) cells in the cochlear nucleus (CN). Some genes of stem/progenitor markers in sorted SP cells were identified by microarray analysis and RT-PCR. Furthermore, some cells in the CN also demonstrated self-renewal and clonal expansion activities. These results suggest that tissue stem/ progenitor like cells would be identified and characterized as a slow cycling and immaturity in SP cells of CN.


OBJECTIVE
SP cells were sorted and characterized as regards their activity in the CN in order to identify the tissue progenitor/stem cells in the auditory nervous system.


METHODS
Bromodeoxyuridine (BrdU)-injected mice were prepared and the long-term BrdU-retaining cells were detected by flow cytometry. Gene expression of SP and MP cells was analyzed by microarray analysis and RT-PCR. SP cells were cultured in conditioned medium to expand stem/progenitor cells in vitro and to estimate the spheroid-forming activity of stem cells.


RESULTS
In all, 1% of cells in the CN were detected as BrdU-positive. SP cells were detected at a frequency of 4.4% and expressed stem/progenitor markers, Abcb1b, Abcg2, Sca1, Notch1, Notch4, Hes1, and Jag1 in microarray analysis. Expression of Abcb1b, Abcg2, Sca1,Oct3/4, and Sox2 as determined by RT-PCR was supported by the microarray data. CN cells also had sphere-forming activity in young mice, but this activity was decreased by aging.
Regeneration Research Center for Intractable Diseases, Kansai Medical University, Osaka, Japan.
Hisashi
H
Ooka
Seiji
S
Kanda
Haruka
H
Okazaki
Hiroko
H
Suzuki
Kenji
K
Mishima
Ichiro
I
Saito
Masao
M
Yagi
Koichi
K
Tomoda
Toshimasa
T
Nishiyama
D000818:Animals; D001306:Auditory Pathways / Q000166:cytology* / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D017626:Cochlear Nucleus / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D058985:Side-Population Cells / Q000166:cytology / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology
D015415:Biomarkers; D014157:Transcription Factors