Lipid guideposts

摘要

Various proteins act as spatial cues in axon guidance, but whether lipids can serve a similar function has been unclear. A new study now shows that a glial cell-derived glycerophospho-lipid acts as a repulsive spatial cue during the pathfinding of nociceptive axons in the embryonic spinal cord of chicks and mice.The membranes of rodent radial glia have been found to contain the glycerophospholipidphosphatidyl-(3-D-glucoside (PtdGlc). In line with this finding, here, Guy et al. found that the large majority of proliferating glia that were isolated from the chick embryo spinal cord showed co-immunolabelling for PtdGlc and transitin, which is a marker of radial glia. Such co-staining was also observed in chick embryo spinal cord sections, with no detection of PtdGlc in neurons. In the medium in which isolated glia were cultured, the authors detected a water-soluble derivative of PtdGlc - LysoPtdGlc -suggesting that these radial glia produce PtdGlc and release its derivative into the extracellular space.