Enhanced Myelination

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DRG-Derived BDNF and Myelination

http://www.medicalnewstoday.com/medicalnews.php?newsid=76424

K. Ng, Lian Chen, Wilhelm Mandemakers, Jos¨¦ M. Cosgaya,

and Jonah R. Chan

Although neurotrophic factors are usually considered to be target-

derived secretory products that are then retrogradely transported to

their site of action, this week Ng et al. provide more proof that

BDNF can move in other directions. The authors examined the source

of BDNF necessary for Schwann cell-mediated myelination of sensory

nerves. BDNF expression increased soon after purified Schwann cells

were cocultured with dorsal root ganglion (DRG) neurons. The

expression was greatest prior to myelination. Using Campenot

chambers, the authors report that BDNF was secreted from the

compartment containing DRG axons as well as the cell body

compartment, consistent with anterograde transport and secretion

from the surface of the axons. Viralmediated gene transfer of myc-

tagged BDNF into DRGs was later detected in Schwann cells,

consistent with transfer of BDNF from DRG to Schwann cell.

Overexpression of BDNF in DRGs also led to anterograde transport,

secretion, and enhanced myelination.