Role of basal lamina in Schwann cell glycolipid biosynthesis

Schwann cells that are deprived of axonal contact switch their glycolipid metabolic pathway from primarily galactocerebroside (GalCe) synthesis to the formation of glucocerebroside (GlcCe) and its homologs. The removal of axonal influence has a dual effect on Schwann cell phenotype; they lose the ability to assemble both myelin and basement membrane. To determine whether a loss of basement membrane directly affects glycolipid expression, we have examined lipid biosynthesis in Schwann cells which were allowed to interact with axons of dorsal root ganglion neurons but which were deprived of the ability to assemble basal lamina. These Schwann cells resemble those from myelinating nerve in that they synthesize a large amount of galactohydroxycerebroside. This suggests that axon contact, even in the absence of basement membrane, is sufficient to induce the GalCe metabolic pathway.Abbreviations DRG dorsal root ganglia - GalCe galactocerebroside - GalCe-OH galactohydroxycerebroside - GlcCe glucocerebroside - GL-2 lactosylceramide - GL-3 trihexosylceramide - GL-4 tetrahexosylceramide - HPTLC high-performance thin-layer chromatography - MGDG monogalactosyl diacylglycerol - NL non-polar lipids - PC phosphatidylcholine - Su sulfatide - Su-OH hydroxysulfatide