Glia And Myelin Dr. Drewes Flashcards
What is myelin composed of?
~30% protein
~70% lipid
How do the Oligodendrocytes myelinated an axon?
By sending out processes and wrapping around the axon
So myelin is really just from the plasma
What are the lipid composition of myelin?
Cholesterol
Galactolipid (more here than other places)
Phospholipid
The galactolipid content (22.6) is indicative of myelin
How is myelin produced?
From the fatty acids
A serine attached
A sugar
What is a lipid called when a galactose is added to it?
Galactocerebroside
What is a galactocerebroside with a sulfate group called?
A sulfatide
What is a lipid with a glucose attached to it?
Glucosocerebroside
What is a character of myelin lipids?
Ether linked rather than ester linked
What are the main predominant proteins in myelin in the CNS?
PLP (proteolipidprotein)
What protein is in myelin in he PNS specifically?
PMP-22
P0
What role does protein play in myelin? CNS?
MBP holds layers of myelin together I between membranes
PLP is transmembrane, extra cellular
What do proteins do in myelin in the PNS?
P0 replaces PLP as the transmembrane protein (extra cellular)
MBP bridges gaps in the cytoplasm
When does Myelination occur?
Early life
How can you make more myelin in adulthood?
OPCs (Oligodendrocyte stem cells) can proliferate into Oligodendrocytes
What causes psychiatric diseases in part?
Myelination abnormalities
What is experimental allergic encephalomyelitis?
EAE
A model for MS
Created in mice by inserting myelin from a different animal in the mouse, the mouse then develops antibodies that attack all myelin
What is a good model for Guillain-Barré syndrome?
Experiemental allergic Neuritis
Peripheral myelin insertion
What is PLP and how can disorders happen?
Proteolipidprotein
Whole bunch of acyl chains , very lipid soluble
What can happen to MBP that can cause disorders?
Alternative splicing that may lead to abnormal proteins
When happens if there is too much PMP-22?
Defective myelin is formed
Degeneration of muscle
Gene dosage causes a problem
Why can you see MS on an MRI?
There is more water because there is less fat, therefore more water.
White matter is dark because less water, more fat
What is VCAM-1?
Adherence factor that allows white blood cells to transfer the BBB
What does the white blood cell have that allows It to adhere to VCAM-1?
Alpha4 Beta1 protein
What does natalizumab (tysabri) do?
A monoclonal antibody that attacks alpha4beta1
