Glia

Question 1

Glia

Answer 1

Immune cell. Support network for neurons. Clean up the mess. 50% of cells in brain.others are neurons.

Question 2

Oligodenrocytes

Answer 2

Myelinating cells. From neuroectoderm

Question 3

Astrocytes

Answer 3

From neuroectoderm.

Question 4

Microglia

Answer 4

Macrophages, come into the brain during development. Cell body and fine process extend throughout the brain. Overlap slightly. 5% cells in brain. Immune cells and phacocytotic.

Question 5

How do we look at MG?

Answer 5

Reporter mice - GFP driven by cell specific gene.

Question 6

Development of MG

Answer 6

Macrophage lineage. Present antigens to T cells and initiate inflammation.
Appear in great numbers before birth.
Mature at birth when BBB forms. Multiple functions during development.
Keep out systemic immune system. Little communication between systemic and CNS.
T- cells monitor and go back to systemic immune system.

Question 7

Amoeboid MG

Answer 7

Early MG’s - very active - phacocytotic. After BBB = less cell death and turn into ramified/resting MG (less active)

Question 8

Resting state of MG

Answer 8

Always sampling the area.
Extending processes out (dendrites) to monitor the environment. Dont do anything unless there is damage = activation and phagocytose.
Glutamate main excitatory NT and released when neuron dies = exitotoxticity.
Help kill and remove dying neurons.
Also ATP. Activates purine receptors on MG.

Question 9

What are the ON and OFF signals for MG?

Answer 9

OFF - TGF-b, BDNF, Fractaline.

On - ATP, Toll-like Receptors, TNF, colony stimulating factor.

Question 10

Active MG release many Proinflammatory factors

Answer 10

TNF, IL1B, ROS, NO

Question 11

Purine receptors

Answer 11

P2 - important pharmacological target for controlling MG cells.

Question 12

What happens to cytokines when MG are activated?

Answer 12

Can amplify cytokines. Therefore amplify the signal Make more inflammatory. Some are toxic for other cells.

Question 13

What happens when MG become activated?

Answer 13

Regain macrophage-like status, phagocytic. Present antigen to T-cells. They precipitate immune reactions by t-cells reporting back to the systemic immune system (like in MS).

Question 14

M1 phenotype - classically activated

Answer 14

pro inflammatory - acute infection. MG express certsin number of genes and cytokines. Nitric oxide.

Question 15

M2 phenotype - Alternatively activate

Answer 15

Anti-inflammatory. Tissue remodelling and repair. New BBB. Want to trick them into this phase to premote remodelling and repair. (Stroke/MS).