Myelin galactolipids are essential for proper node of Ranvier formation in the CNS
JOURNAL OF NEUROSCIENCE
Authors: Dupree, JL; Coetzee, T; Blight, A; Suzuki, K; Popko, B
Abstract
The vertebrate myelin sheath is greatly enriched in the galactolipids galactocerebroside (GalC) and sulfatide, Mice with a disruption in the gene that encodes the biosynthetic enzyme UDP-galactose:ceramide galactosyl transferase (CGT) are incapable of synthesizing these lipids yet form myelin sheaths that exhibit major and minor dense lines with spacing comparable to controls, These CGT mutant mice exhibit a severe tremor that is accompanied by hindlimb paralysis. Furthermore, electrophysiological studies reveal nerve conduction deficits in the spinal cord of these mutants. Here, using electron microscopic techniques, we demonstrate ultrastructural myelin abnormalities in the CNS that are consistent with the electrophysiological deficits. These abnormalities include altered nodal lengths, an abundance of heminodes, an absence of transverse bands, and the presence of reversed lateral loops, In contrast to the CNS, no ultrastructural abnormalities and only modest electrophysiological deficits were observed in the peripheral nervous system. Taken together, the data presented here indicate that GalC and sulfatide are essential in proper CNS node and paranode formation and that these lipids are important in ensuring proper axo-oligodendrocyte interactions.
Iminosugar-Based Galactoside Mimics as Inhibitors of Galactocerebrosidase: SAR Studies and Comparison with Other Lysosomal Galactosidases
CHEMMEDCHEM
Authors: Biela-Banas, Anna; Oulaidi, Farah; Front, Sophie; Gallienne, Estelle; Ikeda-Obatake, Kyoko; Asano, Naoki; Wenger, David A.; Martin, Olivier R.
Abstract
Several families of iminosugar-based galactoside mimics were designed, synthesized, and evaluated as galactocerebrosidase (GALC) inhibitors. They were also tested as inhibitors of lysosomal - and -galactosidases in order to find new potent and selective pharmacological chaperones for treatment of the lysosomal storage disorder, Krabbe disease. Whereas 1-C-alkyl imino-L-arabinitols are totally inactive toward the three enzymes, 1-C-alkyl imino-D-galactitols were found to be active only toward -galactosidaseA. Finally, 1-N-iminosugars provided the best results, as 4-epi-isofagomine was found to be a good inhibitor of both lysosomal -galactosidase and GALC. Further elaboration of this structure is required to achieve selectivity between these two galactosidases.