Open AccessPsychosine enhances the shedding of membrane microvesicles: Implications in demyelination in Krabbe’s disease
Author(s) -
Ludovic D’Auria,
Cory R. Reiter,
Emma Ward,
Ana Lis Moyano,
M. Scott Marshall,
Duy Anh Nguyễn,
Giuseppe Scesa,
Zane Hauck,
Richard B. van Breemen,
Maria I. Givogri,
Ernesto R. Bongarzone
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0178103
Subject(s) - krabbe disease , myelin , microbiology and biotechnology , sphingolipid , oligodendrocyte , lipid raft , biology , myelin proteolipid protein , sphingomyelin , leukodystrophy , membrane , cell membrane , microvesicles , chemistry , biophysics , signal transduction , neuroscience , biochemistry , myelin basic protein , medicine , pathology , central nervous system , disease , microrna , gene
In prior studies, our laboratory showed that psychosine accumulates and disrupts lipid rafts in brain membranes of Krabbe’s disease. A model of lipid raft disruption helped explaining psychosine’s effects on several signaling pathways important for oligodendrocyte survival and differentiation but provided more limited insight in how this sphingolipid caused demyelination. Here, we have studied how this cationic inverted coned lipid affects the fluidity, stability and structure of myelin and plasma membranes. Using a combination of cutting-edge imaging techniques in non-myelinating (red blood cell), and myelinating (oligodendrocyte) cell models, we show that psychosine is sufficient to disrupt sphingomyelin-enriched domains, increases the rigidity of localized areas in the plasma membrane, and promotes the shedding of membranous microvesicles. The same physicochemical and structural changes were measured in myelin membranes purified from the mutant mouse Twitcher, a model for Krabbe’s disease. Areas of higher rigidity were measured in Twitcher myelin and correlated with higher levels of psychosine and of myelin microvesiculation. These results expand our previous analyses and support, for the first time a pathogenic mechanism where psychosine’s toxicity in Krabbe disease involves deregulation of cell signaling not only by disruption of membrane rafts, but also by direct local destabilization and fragmentation of the membrane through microvesiculation. This model of membrane disruption may be fundamental to introduce focal weak points in the myelin sheath, and consequent diffuse demyelination in this leukodystrophy, with possible commonality to other demyelinating disorders.