Microglia Flashcards
Do microglia carry action potentials ?
no they are non neural cells in the CNS
What are the four main functions of glia cells?
- support surrounding neurones
- Supply nutrients and oxygen to neurones
- Insulate and facilitate synaptic communication
- Remove cell debris
What are the other roles of glia?
- guide migration in early development
- reg clearance of NT from cleft
- Role in brain disease
Where are microglia derived from? development layer?
the mesoderm/ yolk sac
Where are oligos and astrocytes derived from ?developmental layer?
neuroectoderm
Where are stem HMSCs derived from? developmental layer ?
myeloid
What happens by 6 weeks gestation?
vasculogenesis in the telencephalon
Endothelial BBB formation
What forms from 7 weeks of gestation?
blood-CSF barrier, CSF brain barrier, Pia-arachnoid
All have tight junctions
What progenitors do glia differentiate from in early development ?
neural progenitors
How do oliogodendrites differentiate ?
Stepwise
From Neural glia 2 progenitors to mature myelinating oligodendrities
Where do Schwann cell precursors give rise ?
in the neural crest
peripheral sensory and autonomic neurones
satellite cells of the DRG
Where are multipoint radial-like glia thought to derive?
neural and glia cells
What are the macrophage subpopulations in the brain ?
- microglia
- meninges
- choroid
- perivascular space
- dendritic
What are the characteristics of microglial population ?
Mosaic like
In the parenchyma
variable densities in different regions
What are the roles of microglia in the immune compartment of the brain ? (5)
Surveillance, proliferating, pruning, phagocytosis, neuromodulatory
What gives rise to all macrophage populations in the brain ?
Erythromyeloid progenitors (EMPs) derived from the yolk sac
Why are the immune cells in the brain different to the body immune cells?
they are isolated in the brain due to the closing of the BBB
Brain is colonised directly (without relay of liver) and earlier than other organs
What markers do uncommitted EMPs express?
CD31+ and c-kit+
How do EMPs develop?
via the macrophage population
What drives the specification and acquisition of EMPs into immature macrophages?
PU1, C/EBPs, RUNX1, IRF8
What shapes microglia identity?
intrinsic determinants and brain environmental factors
What does the location of microglia greatly affect?
the genes being expressed
How id the adult microglia population maintained?
balance of proliferation and apoptosis
Majority of brain macrophages aren’t replaced during adulthood and health ageing
