Neural progenitor number is regulated by nuclear factor-kappaB p65 and p50 subunit-dependent proliferation rather than cell survival.
The number of cells generated by a proliferating stem or precursor cell can be influenced both by proliferation and by the degree of cell death/survival of the progeny generated. In this study, the extent to which cell survival controls progenitor number was examined by comparing the growth characteristics of neurosphere cultures derived from mice lacking genes for the death-inducing Bcl-2 homologue Hara Kiri (Hrk), apoptosis-associated protein 1 (Apaf1), or the prosurvival nuclear factor-kappaB (NFkappaB) subunits p65, p50, or c-rel. We found no evidence that Hrk or Apaf1, and by inference the mitochondrial cell death pathway, are involved in regulating the number of neurosphere-derived progeny. However, we identified the p65p50 NFkappaB dimer as being required for the normal growth and expansion of neurosphere cultures. Genetic loss of both p65 and p50 NFkappaB subunits resulted in a reduced number of progeny but an increased proportion of neurons. No effect on cell survival was observed. This suggests that the number and fate of neural progenitor cells are more strongly regulated by cell cycle control than survival.
Young
Kaylene M
KM
Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia.
Bartlett
Perry F
PF
Coulson
Elizabeth J
EJ
D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000502:physiology; D053477:Apoptotic Protease-Activating Factor 1; D002452:Cell Count; D016923:Cell Death / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D002470:Cell Survival / Q000502:physiology*; D019254:Genes, bcl-2 / Q000502:physiology; D020573:Genes, rel / Q000502:physiology; D005838:Genotype; D007150:Immunohistochemistry; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D052002:NF-kappa B p50 Subunit / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D009479:Neuropeptides / Q000502:physiology; D009924:Organ Culture Techniques; D011506:Proteins / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000502:physiology*; D051996:Transcription Factor RelA / Q000502:physiology*
C506593:Apaf1 protein, mouse; D051017:Apoptosis Regulatory Proteins; D053477:Apoptotic Protease-Activating Factor 1; C107631:Hrk protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D052002:NF-kappa B p50 Subunit; D009479:Neuropeptides; D011506:Proteins; D051996:Transcription Factor RelA