white matter disorders

Question 1

what is myelin? what is it function?

Answer 1

white matter of the brain and a di-electric material

forms a sheath around axons allowing for fast propogation of AP

may protect and provide metabolic support too

Question 2

which cells form myelin

Answer 2

oligodendrocytes in CNS
Schwann cells in PNS
olfactory sensory cell

Question 3

do all organisms have myelin?

Answer 3

only veterbrates have this so myelin was an evolutionary adaptation

Question 4

how do CNS and PNS myelin proteins differ?

Answer 4

PNS has proteinG, FA synthase

CNS has myelin basic protein and proteolipid

Question 5

how does myelin undergo metabolism?

Answer 5

oligodendrocytes have GLUT1 to take up glucose from capillary and undergoes glycolysis

lactate able to enter axon through MCT1/2 transporter

Question 6

how does CNS myelin form?

Answer 6

neuronal stem cell to a oligodendrocyte progenitor cell

goes to premyelinatig oligodendrocyte

this can differentiate to oligo or astrocyte

Question 7

which markers do OPC express?
A PDGFR-alpha
B O4
C Myelin BP
D Olig 1/2

Answer 7

OPTION A

MBP and Olig 1/2 expressed by mature oligodendrocyte

Question 8

what is a unique property of myelin?

Answer 8

it has plasticity and is constantly remodelled

Question 9

what are white matter disorders?

Answer 9

group of heterogenous disorders where white brain matter is degraded

Question 10

what is a characteristics of Alexander Disease?

Answer 10

its a leukodystrophy characterised by rosenthal fibres (GFAP aggregate) and elongated cell bodies

Question 11

what are leukodystrophys?

Answer 11

group of inherited neurological disorders affecting the myelin

Question 12

what is the cause of Pelizaeus Merzbacher disease?

Answer 12

rare mutation in the PLP gene and is a hypomyelinating leukodystrophy

Question 13

what is a cause of MS?

Answer 13

its a demyelinating autoimmune disease with plaques forming in white matter

Question 14

what are Jimpy mice

Answer 14

way to model Pelizaeus Merzbacher disease

these mice lack PLP-CTD so have problems with motor function

Question 15

how can we model Alexander disease?

Answer 15

an OE of GFAP doesn’t work in mice so instead cell models are used

use iPSC to visualise rosenthal fibres

Question 16

how can we model MS?

Answer 16

quite hard as it is a hetrogenous, mutli-pathological disease

can use animal model, xennograft or iPSC

Question 17

what are some common issues of MS animal models?

Answer 17

inflammation aspect and insight into immunological mechanism behind MS isn’t modelled

also lesions and progression isn’t modelled