Abstrakt
Meninges comprise three distinct layers, the dura mater, arachnoid, and pia mater that surround the brain, spinal cord and some parts of the nerves. Tradi- tionally the meninges were believed to serve only as protection for tissues that they encase.
However recent work shows they have other important functions related to development and regulation of the nervous system. Given the impor- tance of the meninges, it is surprising that we know very little about their devel- opment.
The embryological origin of the meninges has been debated for over a hundred years. Some studies imply that the meninges develop from the neural crest, while others suggest that they come from the somites.
Here, we investi- gated the temporal development of meninges in birds and mice and found they form at comparable stages. We investigated the origin of avian spinal meninges using chick/quail cell tracing protocols and found they do not develop from the somites as previously thought.
We propose that meningeal epithelial blood vessels may have been mistaken as meninges and led to an erroneous conclu- sion by previous investigators. We present data that show that avian spinal me- ninges originated from the neural crest supported by data demonstrating that they express the neural crest marker HNK1.
Finally using the Wnt1-Cre mouse we show that trunk meninges of mammals also originate from neural crest.