Open AccessReduced ceramide synthase 2 activity causes progressive myoclonic epilepsy
Author(s) -
Mosbech MaiBritt,
Olsen Anne S. B.,
Neess Ditte,
BenDavid Oshrit,
Klitten Laura L.,
Larsen Jan,
Sabers Anne,
Vissing John,
Nielsen Jørgen E.,
Hasholt Lis,
Klein Andres D.,
Tsoory Michael M.,
Hjalgrim Helle,
Tommerup Niels,
Futerman Anthony H.,
Møller Rikke S.,
Færgeman Nils J.
Publication year - 2014
Publication title -
annals of clinical and translational neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.824
H-Index - 42
ISSN - 2328-9503
DOI - 10.1002/acn3.28
Subject(s) - sphingolipid , ceramide , sphingomyelin , ceramide synthase , blot , immunofluorescence , epilepsy , biology , biochemistry , microbiology and biotechnology , gene , cholesterol , immunology , antibody , apoptosis , neuroscience
Objective Ceramides are precursors of complex sphingolipids (SLs), which are important for normal functioning of both the developing and mature brain. Altered SL levels have been associated with many neurodegenerative disorders, including epilepsy, although few direct links have been identified between genes involved in SL metabolism and epilepsy. Methods We used quantitative real‐time PCR , Western blotting, and enzymatic assays to determine the m RNA , protein, and activity levels of ceramide synthase 2 ( CERS 2) in fiibroblasts isolated from parental control subjects and from a patient diagnosed with progressive myoclonic epilepsy ( PME ). Mass spectrometry and fluorescence microscopy were used to examine the effects of reduced CERS 2 activity on cellular lipid composition and plasma membrane functions. Results We identify a novel 27 kb heterozygous deletion including the CERS 2 gene in a proband diagnosed with PME . Compared to parental controls, levels of CERS 2 m RNA , protein, and activity were reduced by ~50% in fibroblasts isolated from this proband, resulting in significantly reduced levels of ceramides and sphingomyelins containing the very long‐chain fatty acids C24:0 and C26:0. The change in SL composition was also reflected in a reduction in cholera toxin B immunofluorescence, indicating that membrane composition and function are altered. Interpretation We propose that reduced levels of CERS 2, and consequently diminished levels of ceramides and SLs containing very long‐chain fatty acids, lead to development of PME .