Send to

Choose Destination
See comment in PubMed Commons below
Proteomics Clin Appl. 2007 Nov;1(11):1446-61. doi: 10.1002/prca.200700522. Epub 2007 Oct 16.

Oligodendrocytes secrete exosomes containing major myelin and stress-protective proteins: Trophic support for axons?

Author information

Department of Biology, Unit of Molecular Cell Biology, University of Mainz, Germany.


Oligodendrocytes synthesize the CNS myelin sheath by enwrapping axonal segments with elongations of their plasma membrane. Spatial and temporal control of membrane traffic is a prerequisite for proper myelin formation. The major myelin proteolipid protein (PLP) accumulates in late endosomal storage compartments and multivesicular bodies (MVBs). Fusion of MVBs with the plasma membrane results in the release of the intralumenal vesicles, termed exosomes, into the extracellular space. Here, we show that cultured oligodendrocytes secrete exosomes carrying major amounts of PLP and 2'3'-cyclic-nucleotide-phosphodiesterase (CNP). These exosomes migrated at the characteristic density of 1.10-1.14 g/mL in sucrose density gradients. Treatment of primary oligodendrocytes with the calcium-ionophore ionomycin markedly increased the release of PLP-containing exosomes, indicating that oligodendroglial exosome secretion is regulated by cytosolic calcium levels. A proteomic analysis of the exosomal fraction isolated by sucrose density centrifugation revealed in addition to PLP and CNP, myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) as constituents of oligodendroglial exosomes, together with a striking group of proteins with proposed functions in the relief of cell stress. Oligodendroglial exosome secretion may contribute to balanced production of myelin proteins and lipids, but in addition exosomes may embody a signaling moiety involved in glia-mediated trophic support to axons.

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Wiley
    Loading ...
    Support Center