Myelin and Iron

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J Neurosci Res. 2004 Sep 1;77(5):681-9.

(NOTE: While this abstract is from last fall, it is important for us

with CMT because it mentions iron is essential for myelination.

Myelin is the wrapping around our nerves. And loss of myelin is a

characterization of CMT 1A. ~ Gretchen)

Effect of manipulation of iron storage, transport, or availability on

myelin composition and brain iron content in three different animal

models.

Ortiz E, Pasquini JM, K, Felt B, Butkus G, Beard J, Connor

JR.

Biological Chemistry Department, School of Pharmacy and Biochemistry,

University of Buenos Aires, Buenos Aires, Argentina.

Several observations suggest that iron is an essential factor in

myelination and oligodendrocyte biology. However, the specific role

of iron in these processes remains to be elucidated. This role could

be as an essential cofactor in metabolic processes or as a

transcriptional or translational regulator.

In this study, we used animals models each with a unique defect in

iron availability, storage, or transfer to test the hypothesis that

disruptions in these mechanisms affect myelinogenesis and myelin

composition. Disruption of iron availability either by limiting

dietary iron or by altering iron storage capacity resulted in a

decrease in myelin proteins and lipids but not the iron content of

myelin. Among the integral myelin proteins, proteolipid protein was

most consistently affected, suggesting that limiting iron to

oligodendrocytes results not only in hypomyelination but also in a

decrease in myelin compaction.

Mice deficient in transferrin must receive transferrin injections

beginning at birth to remain viable, and these mice had increases in

all of the myelin components and in the iron content of the myelin.

This finding indicates that the loss of endogenous iron mobility in

oligodendrocytes could be overcome by application of exogenous

transferrin.

Overall, the results of this study demonstrate how myelin composition

can be affected by loss of iron homeostasis and reveal specific

chronic changes in myelin composition that may affect behavior and

attempts to rescue myelin deficits.