Differentiation prevents assessment of neural stem cell pluripotency after blastocyst injection.
Earlier studies reported that neural stem (NS) cells injected into blastocysts appeared to be pluripotent, differentiating into cells of all three germ layers. In this study, we followed in vitro green fluorescent protein (GFP)-labeled NS and embryonic stem (ES) cells injected into blastocysts. Forty-eight hours after injection, significantly fewer blastocysts contained GFP-NS cells than GFP-ES cells. By 96 hours, very few GFP-NS cells remained in blastocysts compared with ES cells. Moreover, 48 hours after injection, GFP-NS cells in blastocysts extended long cellular processes, ceased expressing the NS cell marker nestin, and instead expressed the astrocytic marker glial fibrillary acidic protein. GFP-ES cells in blastocysts remained morphologically undifferentiated, continuing to express the pluripotent marker stage-specific embryonic antigen-1. Selecting cells from the NS cell population that preferentially formed neurospheres for injection into blastocysts resulted in identical results. Consistent with this in vitro behavior, none of almost 80 mice resulting from NS cell-injected blastocysts replaced into recipient mothers were chimeric. These results strongly support the idea that NS cells cannot participate in chimera formation because of their rapid differentiation into glia-like cells. Thus, these results raise doubts concerning the pluripotency properties of NS cells.
Department of Neurology, University of Massachusetts Medical School, Worcester, USA.
Béatrice
B
Gréco
Hoi Pang
HP
Low
Eric C
EC
Johnson
Rebecca A
RA
Salmonsen
Judith
J
Gallant
Stephen N
SN
Jones
Alonzo H
AH
Ross
Lawrence D
LD
Recht
D000818:Animals; D001483:Base Sequence; D001755:Blastocyst / Q000166:cytology*; D002454:Cell Differentiation / Q000502:physiology*; D017931:DNA Primers; D005260:Female; D016332:Fetal Tissue Transplantation / Q000502:physiology*; D017930:Genes, Reporter; D005819:Genetic Markers; D049452:Green Fluorescent Proteins / Q000235:genetics; D006579:Heterozygote; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009420:Nervous System / Q000166:cytology*; D011247:Pregnancy; D013234:Stem Cells / Q000166:cytology*; D018183:Transplantation Chimera
D017931:DNA Primers; D005819:Genetic Markers; D049452:Green Fluorescent Proteins