Stem cells in the central nervous system Flashcards
What cell layer (during gastrulation) gives rise to the central nervous system?
The ectoderm
What is the neuroepithelium?
Also called the neuroectoderm or the neural plate. It is a pseudostratified cell layer with a specific gene expression and cell-adhesion molecules.
What is neural induction?
The development of embryonic neural stem cells
What are the characteristics of neuroepithelial progenitor cells?
They are polarized, and during proliferation they have interkinetic nuclear migration, and they therefore form a pseudostratified layer
What are the similarities and differences between neuroepithelial cells and radial glia?
They both attach to the apical surface and have a basal process. Their differences are markers (Pax6 in radial glia) and asymmetric cell division
What are the functions of radial glia?
Stem cells. Guides migration of neuronal precursors.
How is progenitor differentiation regulated in CNS development?
Proneural genes
Lateral inhibition
Asymmetric cell division
What is lateral inhibition?
When differentiating cells inhibit differentiation and promote stem cell character in their neighbours. It is contact dependent (cell-to-cell communication).
Notch/Delta signalling
Describe the role of Notch in lateral inhibition
Proneural genes induce a cell surface signal molecule (Delta). Delta activates Notch in neighbouring cells. Notch signalling inhibits proneural gene expression in neighbouring cells
What are the delta-notch status of a stem cell versus a neuroblast?
Stem cell: Delta low, Notch high
Neuroblast: Delta high, Notch low
What are the stem cell genes in the CNS?
Hes and Sox
Why does the human brain have an increased number of neurons?
Increased amount of progenitor cells
Where does adult neurogenesis occur in humans and rodents?
Rodents: Hippocampus and olfactory bulb.
Humans: Hippocampus
What regulates adult neurogenesis?
Brain activity and neurotransmitter signals
