Axonal regulation of Schwann cell glycolipid biosynthesis.
Schwann cell biosynthesis of glycolipids was studied by in vitro incorporation of [3H]galactose into neonatal rat sciatic nerves before and after endoneurial explant culture and in culture of purified Schwann cells. In neonatal nerves prior to culture, [3H]galactose was actively incorporated into galactocerebrosides (GalCe), monogalactosyl diacylglycerol (MGDG), and the sulfatides (Su). In contrast, the incorporation of [3H]galactose into MGDG, GalCe, and Su was nearly undetected in endoneurial explants after 4 days in vitro (div). Instead, there was increased 3H-labeling of glucocerebrosides (GlcCe) and its homologues, with tetrahexosylceramides (GL-4) being a major product, which continued through 8 div. This shift in glycolipid biosynthesis was further demonstrated in the purified Schwann cell cultures. These observations, together with our early findings in the permanent transection paradigm support a direct role of axons in specifying Schwann cell biosynthesis of the GalCe, MGDG, and Su and that the absence of this Schwann cell-axon interaction results in the phenotypic expression of glucocerebroside homologues by the Schwann cell.
Yao
J K
JK
Department of Veterans Affairs Medical Center, Pittsburgh, PA 15206.
Windebank
A J
AJ
Poduslo
J F
JF
Yoshino
J E
JE
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism; D001369:Axons / Q000502:physiology*; D002478:Cells, Cultured; D002518:Ceramides / Q000096:biosynthesis; D004075:Diglycerides / Q000096:biosynthesis; D038983:Galactolipids; D005690:Galactose / Q000378:metabolism; D005699:Galactosylceramides / Q000096:biosynthesis; D005963:Glucosylceramides / Q000096:biosynthesis; D006017:Glycolipids / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D012583:Schwann Cells / Q000378:metabolism*; D012584:Sciatic Nerve; D013433:Sulfoglycosphingolipids / Q000378:metabolism
D002518:Ceramides; D004075:Diglycerides; D038983:Galactolipids; D005699:Galactosylceramides; D005963:Glucosylceramides; D006017:Glycolipids; D013433:Sulfoglycosphingolipids; C009909:monogalactosyldiacylglycerol; D005690:Galactose