Reduced ceramide synthase 2 activity causes progressive myoclonic epilepsy
MB Mosbech, ASB Olsen, D Neess… - Annals of clinical …, 2014 - Wiley Online Library
MB Mosbech, ASB Olsen, D Neess, O Ben‐David, LL Klitten, J Larsen, A Sabers, J Vissing…
Annals of clinical and translational neurology, 2014•Wiley Online LibraryObjective 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 …
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 …
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 mRNA, protein, and activity levels of ceramide synthase 2 (CERS2) 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 CERS2 activity on cellular lipid composition and plasma membrane functions.
Results
We identify a novel 27 kb heterozygous deletion including the CERS2 gene in a proband diagnosed with PME. Compared to parental controls, levels of CERS2 mRNA, 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 CERS2, and consequently diminished levels of ceramides and SLs containing very long‐chain fatty acids, lead to development of PME.
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