DGN - Microglia and other Brain Immune Cells

Question 1

Name the types of Microglia (5)

Answer 1

• Surveillant microglia
• Proliferating microglia
• Pruning microglia
• Neuromodulatory microglia
• Phagocytic microglia

Question 2

What factors contribute to Microglial diversity? (3)

Answer 2

• Morphological diversity
• Regional density
• Different turnover rates

Question 2

Describe the Transcriptional and functional diversity in mice and humans

Answer 2

Core transcriptional module exists with homology between species

• Environment-dependent transcriptional module includes GWAS gene hits for diseases like Alzheimer’s, Parkinson’s, and Multiple Sclerosis

Question 3

What is synaptic pruning?

Answer 3

The process by which the brain eliminates extra neurons and synapses, crucial for circuit refinement during development

Question 4

Explain the experimental paradigm for synaptic pruning (2)

Answer 4

• Retinal ganglion cells (RGCs) form synaptic connections with relay neurons throughout the dorsal lateral geniculate nucleus (dLGN) of the thalamus
• During the postnatal pruning period, RGC synaptic inputs originating from the same eye as well as between eyes compete for territory throughout the dLGN

Question 5

How does microglial activity affect forebrain wiring?

Answer 5

Perturbations in microglial activity affect the outgrowth of dopaminergic axons in the forebrain and the laminar positioning of neocortical interneurons

Question 6

What role does microglia play in apoptotic cell clearance?

Answer 6

Microglia are involved in removing apoptotic cells, crucial for development and adult neuroprotection

Question 7

What are the immune roles of microglia? (2)

Answer 7

• Microglia maintain homeostasis and have functions in synaptic modulation
• They also re-activate immune functions in response to disruption, playing central roles in neurodegenerative diseases

Question 8

Summarize the key points about microglia (3)

Answer 8

• Microglia exhibit phenotypical complexity influenced by region and age
• They are crucial for brain development, including circuit refinement
• In the healthy adult brain, they adopt a surveillant/homeostatic profile but re-activate immune functions in response to challenges or diseases, particularly chronic neurodegenerative diseases