Saturday, 29 September 2012

Research: Making Myelination


Current methods for studying central nervous system myelination necessitate permissive axonal substrates conducive to myelin wrapping by oligodendrocytes. We have developed a neuron-free culture system in which electron-spun nanofibers of varying sizes substitute for axons as a substrate for oligodendrocyte myelination, thereby allowing manipulation of the biophysical elements of axonal-oligodendroglial interactions. To investigate axonal regulation of myelination, this system effectively uncouples the role of molecular (inductive) cues from that of biophysical properties of the axon. We use this method to uncover the causation and sufficiency of fiber diameter in the initiation of concentric wrapping by rat oligodendrocytes. We also show that oligodendrocyte precursor cells display sensitivity to the biophysical properties of fibre diameter and initiate membrane ensheathment before differentiation. The use of nanofibre scaffolds will enable screening for potential therapeutic agents that promote oligodendrocyte differentiation and myelination and will also provide valuable insight into the processes involved in remyelination.


Making myelinating cultures is technically challenging because to have to first make nerves and then get oligodendrocytes to myelinate them. Nerves are cells that do not like to grow and so you end up using feotal cutlures to produce them or use stem cells to grow them. This study shows that you can use fibres to replace nerves and this then allows you to get an assay going to test drugs on ways to test myelination.

4 comments:

  1. There's a picture on the macrophage wikipedia page of a macrophage "stretching it's 'arms' to engulf two particles". Now when I see pictures of oligodendrocytes I see that they also have 'arms' that wrap around the nerves to myelinate them.

    It's amazing to me that without eyes or a brain, these cells have such complex behavior. How do they know when to 'reach out'? How do they know to leave spaces for the 'nodes of ranvier'. I guess it's all chemical communication. Do we know how these cells decide to reach out? Do we know the maximum number of 'arms' they can have? In the drawings they appear to let go leaving the myelin behind, do they then move on to myelinate other nerve areas? This is probably what the research is about.

    It's hard not to anthropomorphize the cells. As a fan of evolution I understand how absolutely amazing things can happen without there having to be a conscious mind behind it, but it still amazes me.

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  2. There are some intersting videos of fluorescent cells taken in living animals using a two photon microscopy

    Check out this pHD thesis for some interesting picture

    http://theses.gla.ac.uk/3435/01/2012IoannidouPhD1.pdf

    Like Microglia they are never static they move aound ad are constantly throughing out processes-sensing the environment as you say with chemical communication. When they contact things receptors on the surface signal the cell to do its stuff in a sterotyped behaviour

    Oligodendrocytes are the same, They can send processes around about 50 axons whereas a schawann cell in the peripheral nerves do one only. Therefore you can see why if you kill one oligodendrocyte youcan affect alot of nerves.

    They wrap round ability like a roller-blind once they attach to the nerve. Some of the myelin proteins are inhibitory for certain processes such as myelin associated glycoprotein and in synapes there is an orderly structure of different proteins that do different things like neuofascin and caspr pronouced casper.

    The cells recieve signals all the time and depending on the concentration and type of signals will determine what happens

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  3. Is this a new approach to studying myelination? In your opinion, how important is this work?

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  4. Its new to me..but you may know otherwise. The use of biofibres in neurobiology is not new, even in our departmentment people are developing spider fibres for nerve growth.

    The importance will be how the authors and others use it. It is one more step in the right direction

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