Mass spectrometric analysis reveals changes in phospholipid, neutral sphingolipid and sulfatide molecular species in progressive epilepsy with mental retardation, EPMR, brain: A case study

Institute of Biomedicine, Department of Biochemistry, University of Helsinki, Helsinki, Finland.
Journal of Neurochemistry (Impact Factor: 4.28). 12/2005; 95(3):609-17. DOI: 10.1111/j.1471-4159.2005.03376.x
Source: PubMed


Progressive epilepsy with mental retardation, EPMR, belongs to a group of inherited neurodegenerative disorders, the neuronal ceroid lipofuscinoses. The CLN8 gene that underlies EPMR encodes a novel transmembrane protein that localizes to the endoplasmic reticulum (ER) and ER-Golgi intermediate compartment. Recently, CLN8 was linked to a large eukaryotic protein family of TLC (TRAM, Lag1, CLN8) domain homologues with postulated functions in lipid synthesis, transport or sensing. By using liquid chromatography/mass spectrometry we analysed molecular species of major phosholipid and simple sphingolipid classes from cerebral samples of two EPMR patients representing a progressive and advanced state of the disease. The progressive state brain showed reduced levels of ceramide, galactosyl- and lactosylceramide and sulfatide as well as a decrease in long fatty acyl chain containing molecular species within these classes. Among glycerophospholipid classes, an increase in species containing polyunsaturated acyl chains was detected especially in phosphatidylserines and phosphatidylethanolamines. By contrast, saturated and monounsaturated species were overrepresented among phosphatidylserine, phosphatidylethanolamine and phosphatidylinositol classes in the advanced state sample. The observed changes in brain sphingo- and phospholipid molecular profiles may result in altered membrane stability, lipid peroxidation, vesicular trafficking or neurotransmission and thus may contribute to the progression of the molecular pathogenesis of EPMR.

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Available from: Pentti Somerharju, Oct 13, 2014
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    • "During this extraction, three phases are produced, an organic phase and a water phase that are separated with an interphase, usually containing denatured proteins. Organic phase is specifically denser and contains lipids that can be isolated from it with high efficiency (Hermansson et al. 2005; Kaddurah-Daouk et al. 2007). Many other modified extraction methods have been used, such as different proportions of butanol and methanol method (Löfgren et al. 2012), mixed isopropanol and hexane method (Schwarz et al. 2008), methyltertbutylether-based LLE method (Chen et al. 2013), tertbutylmethylether and methanol method (Wood et al. 2015) among others. "

    The World Journal of Biological Psychiatry 11/2015; DOI:10.3109/15622975.2015.1117656 · 4.18 Impact Factor
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    • "At least 24 different mutations, either deletion or missense, are linked to CLN8 diseases and mostly to the vLINCL form [1]. Using the naturally-occurring mnd (motor neuron degeneration) mouse model (Cln8 mnd mouse) exhibiting a disease phenotype similar to that of CLN8-vLINCL [17] [21] [22], numerous studies have shown altered lipid metabolism, oxidative and ER stresses, mitochondrial dysfunction, defects in calcium homeostasis, inflammation and apoptosis [23] [24] [25] [26] [27] [28] [29]. Changes in brain lipids and ER-stress responses in fibroblast cells have been also reported in EPMR patients [30] [31]. However, due to the still undefined CLN8 function, the primary defect underlying CLN8- associated diseases remains an open question. "
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    ABSTRACT: Neuronal ceroid lipofuscinoses (NCLs) are a genetically heterogeneous group of neurodegenerative diseases characterized by cognitive and motor decline, epilepsy, visual loss and by lysosomal autofluorescent inclusions. Two distinct clinical phenotypes, the progressive epilepsy with mental retardation (EPMR) and a late-infantile variant of NCLs (CLN8-vLINCL) are associated with mutations in the CLN8 gene that encodes a transmembrane protein predominantly located to the endoplasmic reticulum (ER). To gain insight into the function of CLN8 protein, we employed the split-ubiquitin membrane-based yeast two-hybrid (MYTH) system, which detects protein-protein interactions in a membrane environment, using the full-length human CLN8 as bait and a human brain cDNA library as prey. We identified several potential protein partners of CLN8 and especially referred to VAPA, c14orf1/hERG28, STX8, GATE16, BNIP3 and BNIP3L proteins that are associated with biologically relevant processes such as synthesis and transport of lipids, vesicular/membrane trafficking, autophagy/mitophagy and apoptosis. Interactions of CLN8 with VAPA and GATE16 were further validated by co-immunoprecipitation and co-localization assays in mammalian cells. Using a new C-terminal-oriented CLN8 antibody, CLN8-VAPA interaction was also confirmed by co-staining in close spatial proximity within different CNS tissues. The results of this study shed light on potential interactome networks of CLN8 and provide a powerful starting point for understanding protein function(s) and molecular aspects of diseases associated with CLN8 deficiency.
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    • "Elevation of sulfatide by 30%–40% has also been found in the superior frontal and cerebellar gray matter in Parkinson's disease patients (Eckhardt, 2008). By contrast, substantial decrease in SF has been observed in a case of progressive epilepsy with mental retardation (Hermansson et al., 2005) and in the brain and cerebrospinal fluid of Alzheimer's disease patients (Eckhardt, 2008; Han, 2007; 2010). Not surprisingly, sulfatide homeostasis is critical for the normal function of central and peripheral nerves. "
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