Topic 3 Neurovascular Development Flashcards
name the brain barriers
the meninges - dura mater, arachnoid mater, pia mater
blood brain barrier
blood cerebrospinal fluid barrier
list features of BBB
Tight junctions (no paracellular transport)
low rates of transcytosis
non-fenestrated
lipophillic cross BBB
what are angioneurins?
several families of shared molecular guidance cues that guide both endothelial cells and neurons
what cells does the neural tube recruit on E8.5 when the neural tube is avascular?
angioblasts - endothelial cell precursors
what happens after the recruitment of angioblasts
this is the vasculogenesis of the neural tube, the formation of the perineural vascular plexus (PVNP)
what do Neural progenitor cells secrete to attract angioblasts?
VEGF-A
what two signalling molecules/pathways are needed for blood vessel ingression into the neural tube
Wnt7 and VEGF-A signalling needed to form the Intraneural Vascular Plexus (INVP)
what do radial glial cells express in hypoxic and poorly-vascularized environments
HIF1-alpha
what does HIF1-ALPHA trigger
glycoloysis and RGC proliferation
how does vascularization impact HIF1-alpha expression
oxygenation via vascularization will suppress HIF1-alpha expression
what do Tip cells extend to directly contact RGC and what does this do?
the Tip cells from ingrowing blood vessels contact the RGCs via extension of filopodia, this prolongs the mitotic phase of cell division in RGCs and favours early neuronal differentiation
Wnt signalling from neurons to endothelial cells promotes expression of ?
B-catenin
what do endothelial cells secrete to mediate pericyte recruitment?
ECs secrete PDGF-BB which interacts with PDGFR-beta in pericytes which induces pericyte recruitment
what do astrocytes release to act on endothelial patched homolog 1 (PTC-1) to contribute to BBB formation
astrocytes release sonic hedgehog which acts on endothelial PTC-1 receptor, this elicits signalling to contibute to BBB formation
what do endothelial cells secrete to contribute to proper neurovascular patterning?
endothelial cells secrete VEGF and IGF-1 which contributes to proper neurovascular patterning
describe the vascular-guided migration of oligodendrocyte precursors
OLPs are guided by the vasculature
OLPs secrete Wnt which acts in an autocrine manner to induce expression of CXCR4
ECs secrete CXCL12 (the ligand for CXCR4) to attract OLPs and sustain their undifferentiated state.
maturation of oligodendrocytes is accompanied by:
downregulation of Wnt expression, as well as CXCR4
where are new neurons continuously generated postnatally?
in the SVZ
which interneurons require vascular guidance for migration
GABAergic neurons have receptors for GABA which is secreted by blood vessels
what does Wnt signal from neurons to endothelial cells
to produce B-catenin which promotes BBB specific genes
what do ECs secrete
endothelial cells secrete PDGF-BB
where are the receptors for PDGF-BB located
on pericytes
what do astrocytes secrete which acts on PTC-1 recepotr
astrocytes released SHH which acts on endothelial patched homolog 1 receptor, elicits signalling that contributes to the BBB formation
what do endohelial cells secrete that contributes to proper neurovascular patternin?
IGF-1 and VEGF
