Early brain development: neural induction and patterning Flashcards
What does the vertebrate CNS consist of?
Neurons, glia (astrocytes, oligodendrocytes, ependymal cells), stem cells, microglia, vascular endothelial cells, pericytes
What is neural induction?
The process in which the differentiation capacity of ectodermal cells is restricted to neural lineage
What cellular changes happen during neural induction?
Changes in gene expression and changes in cell-adhesion molecules
What is unique to stem cells in the neuroepithelium?
They are highly polarized with an apical and a basal process. Their position depends on the cell cycle: pseudostratified layer; interkinetic nuclear migration
What is neurulation?
Neurulation is the folding of the neural plate, which results in the separation of the neuroepithelium in a tubular stucture (neural tube) from the rest of the epithelium.
What tissue signals to start neural induction in humans?
The spemann organizer
What signalling pathway is essential for neural induction?
Inhibition of the BMP signalling pathway.
BMP inhibitors: Noggin, Chordin, Follistatin
What tissue express BMP inhibitors? What is the effect?
The spemann organizer (dorsal blastopore lip). It causes induction of neural fate.
What are the main proteins, that can affect the transcription of neural genes?
Chd and Nog inhibition of BMP.
FGF, IGF, HGF, EGF activation of RTK.
What genes are important for neural stem cell identity? (after neural induction)
Sox genes and Notch regulated TFs (Hes)
What are primary and secondary organizers?
Primary organizers: affect the early developments, comes from outside the neuroepithelium.
Secondary organizers: affect later development, comes from within the neuroepithelium and control refinement of patterning, neurogenesis ect.
What are the primary organizers of anterior-posterior patterning?
AVE and node (affect the Wnt pathway)
What are the secondary organizers of anterior-posterior patterning?
Growth factor signals from within the neuroepithelium
What is the isthmic organizer?
It guides development of the midbrain and anterior hindbrain.
What are the two main signals in dorsal-ventral patterning of the brain?
Dorsal (roof plate) BMP signals and ventral (notochord) Shh signals.
