The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Konrad Sandhoff - One of the best experts on this subject based on the ideXlab platform.
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Characterization of Drosophila Saposin-related mutants as a model for lysosomal sphingolipid storage diseases.
Disease Models & Mechanisms, 2017Co-Authors: Julia Sellin, Heike Schulze, Marie Paradis, Dominic Gosejacob, Cyrus Papan, Andrej Shevchenko, Olympia Ekaterina Psathaki, Achim Paululat, Melanie Thielisch, Konrad SandhoffAbstract:ABSTRACT Sphingolipidoses are inherited diseases belonging to the class of lysosomal storage diseases (LSDs), which are characterized by the accumulation of indigestible material in the lysosome caused by specific defects in the lysosomal degradation machinery. While some LSDs can be efficiently treated by enzyme replacement therapy (ERT), this is not possible if the nervous system is affected due to the presence of the blood-brain barrier. Sphingolipidoses in particular often present as severe, untreatable forms of LSDs with massive sphingolipid and membrane accumulation in lysosomes, neurodegeneration and very short life expectancy. The digestion of intralumenal membranes within lysosomes is facilitated by lysosomal sphingolipid activator proteins (saposins), which are cleaved from a prosaposin precursor. Prosaposin mutations cause some of the severest forms of Sphingolipidoses, and are associated with perinatal lethality in mice, hampering studies on disease progression. We identify the Drosophila prosaposin orthologue Saposin-related (Sap-r) as a key regulator of lysosomal lipid homeostasis in the fly. Its mutation leads to a typical spingolipidosis phenotype with an enlarged endolysosomal compartment and sphingolipid accumulation as shown by mass spectrometry and thin layer chromatography. S ap-r mutants show reduced viability with ∼50% survival to adulthood, allowing us to study progressive neurodegeneration and analyze their lipid profile in young and aged flies. Additionally, we observe a defect in sterol homeostasis with local sterol depletion at the plasma membrane. Furthermore, we find that autophagy is increased, resulting in the accumulation of mitochondria in lysosomes, concomitant with increased oxidative stress. Together, we establish Drosophila Sap-r mutants as a lysosomal storage disease model suitable for studying the age-dependent progression of lysosomal dysfunction associated with lipid accumulation and the resulting pathological signaling events.
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metabolic and cellular bases of Sphingolipidoses
Biochemical Society Transactions, 2013Co-Authors: Konrad SandhoffAbstract:Lysosomes are cellular stomachs. They degrade macromolecules and release their components as nutrients into the cytosol. Digestion of sphingolipids and other membrane lipids occurs at luminal intraendosomal vesicles and IMs (intraendosomal membranes). Sphingolipid and membrane digestion needs catabolic hydrolases with the help of lipid-binding proteins [SAPs (sphingolipid activator proteins)] and anionic lipids such as BMP [bis(monoacylglycero)phosphate]. Inherited defects of hydrolases or SAPs or uptake of cationic amphiphilic drugs cause lipid accumulation, eventually leading to death, especially in inherited sphingolipid storage diseases. IMs are formed during endocytosis and their lipid composition is adjusted for degradation. Their cholesterol content, which stabilizes membranes, decreases and the level of negatively charged BMP, which stimulates sphingolipid degradation, increases. At the level of late endosomes, cholesterol is transported out of the luminal vesicles preferentially by cholesterol-binding proteins, NPC (Niemann–Pick type C)-2 and NPC-1. Their defects lead to an endolysosomal accumulation of cholesterol and sphingolipids in Niemann–Pick type C disease. BMP and ceramide stimulate NPC-2-mediated cholesterol transfer, whereas sphingomyelin inhibits it. Anionic membrane lipids also activate sphingomyelin degradation by ASM (acid sphingomyelinase), facilitating cholesterol export by NPC-2. ASM is a non-specific phospholipase C and degrades more than 23 phospholipids. SAPs are membrane-perturbing proteins which solubilize lipids, facilitating glycolipid digestion by presenting them to soluble catabolic enzymes at acidic pH. High BMP and low cholesterol levels favour lipid extraction and membrane disintegration by saposin A and B. The simultaneous inherited defect of saposins A–D causes a severe membrane and sphingolipid storage disease, also disrupting the water permeability barrier of the skin.
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my journey into the world of sphingolipids and Sphingolipidoses
Proceedings of the Japan Academy. Series B Physical and biological sciences, 2012Co-Authors: Konrad SandhoffAbstract:Analysis of lipid storage in postmortem brains of patients with amaurotic idiocy led to the recognition of five lysosomal ganglioside storage diseases and identification of their inherited metabolic blocks. Purification of lysosomal acid sphingomyelinase and ceramidase and analysis of their gene structures were the prerequisites for the clarification of Niemann-Pick and Farber disease. For lipid catabolism, intraendosomal vesicles are formed during the endocytotic pathway. They are subjected to lipid sorting processes and were identified as luminal platforms for cellular lipid and membrane degradation. Lipid binding glycoproteins solubilize lipids from these cholesterol poor membranes and present them to water-soluble hydrolases for digestion. Biosynthesis and intracellular trafficking of lysosomal hydrolases (hexosaminidases, acid sphingomyelinase and ceramidase) and lipid binding and transfer proteins (GM2 activator, saposins) were analyzed to identify the molecular and metabolic basis of several Sphingolipidoses. Studies on the biosynthesis of glycosphingolipids yielded the scheme of Combinatorial Ganglioside Biosynthesis involving promiscuous glycosyltransferases. Their defects in mutagenized mice impair brain development and function.
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Lysosomal Lipid Storage Diseases
Cold Spring Harbor Perspectives in Biology, 2011Co-Authors: Heike Schulze, Konrad SandhoffAbstract:Lysosomal lipid storage diseases are a group of inherited catabolic disorders in which typically large amounts of complex lipids accumulate in cells and tissues. Macromolecules such as complex lipids and oligosaccharides are constitutively degraded in the acidic compartments of the cell, the endosomes, and lysosomes, into their building blocks. The resulting catabolites are exported to the cytosol and reused in cellular metabolism. When lysosomal function is impaired because of a defect in a catabolic step, degradation cannot proceed normally and undegraded compounds accumulate. Lysosomal lipid storage diseases comprise mainly the Sphingolipidoses, Niemann-Pick type C disease (NPC), and Wolman disease, including the less severe form of this disease, called cholesteryl ester storage. NPC is a complex lipid storage disease mainly characterized by the accumulation of unesterified cholesterol in the late endosomal/lysosomal compartment (Bi and Liao 2010). The Sphingolipidoses are caused by defects in genes encoding proteins involved in the lysosomal degradation of sphingolipids (Kolter and Sandhoff 2006). First reports on these diseases were given more than a century ago. Already in 1881, Warren Tay described the clinical symptoms of a disease, which is today called Tay-Sachs disease (Tay 1881). After Christian de Duve discovered the lysosome in 1955 (de Duve 2005), Henri-Gery Hers established the first correlation between an enzyme deficiency and a lysosomal storage disorder (Pompe’s disease) in 1963 (Hers 1963). In the following decades, the enzymes and cofactors deficient in the Sphingolipidoses have been identified. Though lysosomal lipid storage diseases have been known for a long time, treatment is only available for a few mild forms of the diseases, such as the adult forms of Gaucher disease (Barton et al. 1991). For several lysosomal storage diseases, therapies like enzyme replacement or bone marrow transplantation are in the clinical trial stage (Platt and Lachmann 2009). For a long time, lysosomal diseases have been considered a problem of superabundance (storage) in which the storage material can slowly spread to other cellular membranes, impairing their function. More recently, it came into focus that massive storage prevents lysosomal functions such as nutrition delivery through the endolysosomal system, leading to a state of cellular starvation. In mouse models of both GM1 and GM2 gangliosidoses iron is progressively depleted in brain tissue. Administration of iron prolonged survival in the diseased mice by up to 38% (Jeyakumar et al. 2009).
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Sphingolipid metabolism diseases.
Biochimica et Biophysica Acta, 2006Co-Authors: Thomas Kolter, Konrad SandhoffAbstract:Human diseases caused by alterations in the metabolism of sphingolipids or glycosphingolipids are mainly disorders of the degradation of these compounds. The Sphingolipidoses are a group of monogenic inherited diseases caused by defects in the system of lysosomal sphingolipid degradation, with subsequent accumulation of non-degradable storage material in one or more organs. Most Sphingolipidoses are associated with high mortality. Both, the ratio of substrate influx into the lysosomes and the reduced degradative capacity can be addressed by therapeutic approaches. In addition to symptomatic treatments, the current strategies for restoration of the reduced substrate degradation within the lysosome are enzyme replacement therapy (ERT), cell-mediated therapy (CMT) including bone marrow transplantation (BMT) and cell-mediated “cross correction”, gene therapy, and enzyme-enhancement therapy with chemical chaperones. The reduction of substrate influx into the lysosomes can be achieved by substrate reduction therapy. Patients suffering from the attenuated form (type 1) of Gaucher disease and from Fabry disease have been successfully treated with ERT.
A Burlina - One of the best experts on this subject based on the ideXlab platform.
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plasma and dried blood spot lysosphingolipids for the diagnosis of different Sphingolipidoses a comparative study
Clinical Chemistry and Laboratory Medicine, 2019Co-Authors: Giulia Polo, A Burlina, Enzo Ranieri, Francesca Colucci, Laura Rubert, Antonia Pascarella, Giovanni Duro, Albina Tummolo, Andrea Padoan, Mario PlebaniAbstract:: Background Lysosphingolipids, the N-deacylated forms of sphingolipids, have been identified as potential biomarkers of several Sphingolipidoses, such as Gaucher, Fabry, Krabbe and Niemann-Pick diseases and in GM1 and GM2 gangliosidoses. To date, different methods have been developed to measure various lysosphingolipids (LysoSLs) in plasma. Here, we present a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for a simultaneous quantification of LysoSLs (HexSph, LysoGb3, LysoGM1, LysoGM2, LysoSM and LysoSM509) in dried blood spot (DBS). This LC-MS/MS method was used to compare the levels of LysoSLs in DBS and plasma in both affected patients and healthy controls. Methods Lysosphingolipids were extracted from a 3.2 mm diameter DBS with a mixture of methanol:acetonitrile:water (80:15:5, v/v) containing internal stable isotope standards. Chromatographic separation was performed using a C18 column with a gradient of water and acetonitrile both with 0.1% formic acid in a total run time of 4 min. The compounds were detected in the positive ion mode electrospray ionization (ESI)-MS/MS by multiple reaction monitoring (MRM). Results The method was validated on DBS to demonstrate specificity, linearity, lowest limit of quantification, accuracy and precision. The reference ranges were determined in pediatric and adult populations. The elevated levels of LysoSLs were identified in Gaucher disease (HexSph), Fabry disease (LysoGb3), prosaposin deficiency (HexSph and LysoGb3) and Niemann-Pick disease types A/B and C (LysoSM and LysoSM509). The correlation in the levels between DBS and plasma was excellent for LysoGb3 and HexSph but poor for LysoSM and LysoSM509. Conclusions Despite the fact that plasma LysoSLs determination remains the gold standard, our LC-MS/MS method allows a rapid and reliable quantification of lysosphingolipids in DBS. The method is a useful tool for the diagnosis of different Sphingolipidoses except for Niemann-Pick type C.
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diagnosis of Sphingolipidoses a new simultaneous measurement of lysosphingolipids by lc ms ms
Clinical Chemistry and Laboratory Medicine, 2017Co-Authors: Giulia Polo, A Burlina, Thilini B Kolamunnage, Michele Zampieri, Carlo Dionisivici, Pietro Strisciuglio, Martina Zaninotto, Mario PlebaniAbstract:BACKGROUND: Lysosphingolipids (LysoSLs) are derivatives of sphingolipids which have lost the amide-linked acyl chain. More recently, LysoSLs have been identified as storage compounds in several Sphingolipidoses, including Gaucher, Fabry and Niemann-Pick diseases. To date, different methods have been developed to measure each individual lysosphingolipid in plasma. This report describes a rapid liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) assay for simultaneous quantification of several LysoSLs in plasma. METHODS: We analyzed the following compounds: hexosylsphingosine (HexSph), globotriaosylsphingosine (LysoGb3), lysosphingomyelin (LysoSM) and lysosphingomyelin-509 (LysoSM-509). The sample preparation requires only 100 μL of plasma and consists of an extraction with a mixture of MeOH/acetone/H2O (45:45:10, v/v). RESULTS: The method validation showed high sensitivity, an excellent accuracy and precision. Reference ranges were determined in healthy adult and pediatric population. The results demonstrate that the LC-MS/MS method can quantify different LysoSLs and can be used to identify patients with Fabry (LysoGb3), Gaucher and Krabbe (HexSph) diseases, prosaposine deficiency (LysoGb3 and HexSph), and Niemann-Pick disease types A/B and C (LysoSM and LysoSM-509). CONCLUSIONS: This LC-MS/MS method allows a rapid and simultaneous quantification of LysoSLs and is useful as a biochemical diagnostic tool for Sphingolipidoses.
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Diagnosis of Sphingolipidoses: a new simultaneous measurement of lysosphingolipids by LC-MS/MS.
Clinical Chemistry and Laboratory Medicine, 2017Co-Authors: Giulia Polo, A Burlina, Thilini B Kolamunnage, Michele Zampieri, Pietro Strisciuglio, Martina Zaninotto, Mario Plebani, Carlo Dionisi-viciAbstract:BACKGROUND: Lysosphingolipids (LysoSLs) are derivatives of sphingolipids which have lost the amide-linked acyl chain. More recently, LysoSLs have been identified as storage compounds in several Sphingolipidoses, including Gaucher, Fabry and Niemann-Pick diseases. To date, different methods have been developed to measure each individual lysosphingolipid in plasma. This report describes a rapid liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) assay for simultaneous quantification of several LysoSLs in plasma. METHODS: We analyzed the following compounds: hexosylsphingosine (HexSph), globotriaosylsphingosine (LysoGb3), lysosphingomyelin (LysoSM) and lysosphingomyelin-509 (LysoSM-509). The sample preparation requires only 100 μL of plasma and consists of an extraction with a mixture of MeOH/acetone/H2O (45:45:10, v/v). RESULTS: The method validation showed high sensitivity, an excellent accuracy and precision. Reference ranges were determined in healthy adult and pediatric population. The results demonstrate that the LC-MS/MS method can quantify different LysoSLs and can be used to identify patients with Fabry (LysoGb3), Gaucher and Krabbe (HexSph) diseases, prosaposine deficiency (LysoGb3 and HexSph), and Niemann-Pick disease types A/B and C (LysoSM and LysoSM-509). CONCLUSIONS: This LC-MS/MS method allows a rapid and simultaneous quantification of LysoSLs and is useful as a biochemical diagnostic tool for Sphingolipidoses.
Hatice Asuman Ozkara - One of the best experts on this subject based on the ideXlab platform.
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recent advances in the biochemistry and genetics of Sphingolipidoses
Brain & Development, 2004Co-Authors: Hatice Asuman OzkaraAbstract:Abstract Sphingolipidoses are a subgroup of lysosomal storage diseases. They are defined as disorders caused by a genetic defect in catabolism of sphingosine-containing lipids. Catabolism of these lipids involves enzymes and activator proteins. After the discovery of lysosomes by de Duve and the demonstration of the first defective lysosomal enzyme by Hers in 1963, the first enzyme deficiency for Sphingolipidoses was characterized in 1965 and all the defective enzymes were demonstrated in the last three decades. In 1984, the first activator protein was found and it expanded the concept of Sphingolipidoses. In the following years, many researches have been undertaken to understand the molecular basis of these diseases, the mechanism of pathogenesis, the mechanism of lysosomal digestion of glycosphingolipids (GSLs) and the functional domains of lysosomal enzymes. New hypotheses and theories have been put forward for the mechanism of lysosomal digestion and pathogenesis. However, although much has been done, the pathogenesis of Sphingolipidoses has not been fully elucidated. Mouse models of these diseases have facilitated the elucidation of pathogenesis and the development of therapeutic strategies for these diseases, which are not treatable at present except for Fabry and type 1 Gaucher disease. The purpose of this review is to collect information on the recent researches related to Sphingolipidoses. The review includes the hydrolysis of GSLs in lysosome, mechanism of hydrolysis, pathogenesis and genetics of Sphingolipidoses, a brief mouse model and therapeutic strategies of these diseases.
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Sphingolipidoses in turkey
Brain & Development, 2004Co-Authors: Hatice Asuman Ozkara, Meral TopcuAbstract:Abstract During the last 5 years 2057 children under the age of 5 with various neurologic symptoms with the suspected diagnosis of lysosomal storage diseases were referred to our hospital from different universities and state hospitals. We were able to separate Sphingolipidoses by lysosomal enzyme screening. A total of 300 patients (15%) with Sphingolipidoses were diagnosed; there were deficiencies of arylsulfatase A [metachromatic leukodystrophy (MLD)] in 93 (31%), hexosaminidase [Sandhoff disease (SHD)] in 62 (20.7%), hexosaminidase A [Tay-Sachs disease (TSD)] in 15 (5%), beta-galactosidase (GM1 gangliosidosis) in 35 (11.7%), alpha-galactosidase (Fabry disease) in one (0.3%) cerebroside beta-galactosidase (Krabbe disease) in 65 (21.7%) and glucosylceramidase (Gaucher disease) in 29 (9.6%). SHD (20.7%), MLD (31%) and Krabbe disease (21.7%) were common. Prenatal enzymatic diagnosis was made in 70 at risk pregnancies, 64 for TSD and SHD, three for MLD and three for GM1 gangliosidosis by using chorionic villus biopsy in 54, cord blood samples in 12 and cultured amniotic fluid cells in four. Seventeen fetuses were found to be affected. We have calculated the relative frequency and minimum incidence of Sphingolipidoses in Turkey. The combined incidence of Sphingolipidoses is 4.615 per 100,000 live births. The calculated incidences are 1.43, 0.95, 1, 0.23, 0.54, 0.45, 0.015 per 100,000 live births for MLD, SHD, Krabbe, Gaucher, TSD, GM1 gangliosidosis and Fabry diseases, respectively. The real incidence, which covers all subtypes of this group of diseases, should be greater than this number. The results suggested that, as a group, Sphingolipidoses are relatively common and represent an important health problem in Turkey and some rare autosomal recessive diseases of Turkey are due to ‘founder effect’ created by consanguineous marriages.
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a study on enzyme activities of some Sphingolipidoses
Turkish Journal of Pediatrics, 1994Co-Authors: Hatice Asuman Ozkara, Meral Topcu, M C Arikan, Serap Emre, Yavuz RendaAbstract:: Enzyme activities were determined in fibroblast cell cultures of eight patients suspected of having a type of sphingolipidosis. The patients were 0 to 4 years of age; four were female and four were male. Thirteen age-matched controls were also included in the study. In one of the cases, hexosaminidase A activity was found to be 0% (43-82%), while in two other cases beta-galactosidase activity was found to be 5 nmol/h/mg protein (100-1035 nmol/h/mg protein) and arylsulfatase activity was found to be 12 nmol/h/mg protein (106-990 nmol/h/mg protein), respectively. Two more enzymes, alpha-galactosidase (11-39 nmol/h/mg protein) and cerebroside beta-galactosidase (3.7-6.9 nmol/h/mg protein), were also evaluated but were found to be in the normal ranges in these patients. Therefore, these patients were considered to have Tay-Sachs disease, GM1 gangliosidosis and metachromatic leukodystrophy, respectively. The remaining five patients were normal in respect to the five enzyme activities determined. For the prenatal diagnosis of metachromatic leukodystrophy, arylsulfatase A activity was determined in one amniotic cell culture. The activity found in this case was lower than normal (34 nmol/h/mg protein versus 387 nmol/h/mg protein found in three control amniotic cell cultures.
Olga Amaral - One of the best experts on this subject based on the ideXlab platform.
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advances in Sphingolipidoses crispr cas9 editing as an option for modelling and therapy
International Journal of Molecular Sciences, 2019Co-Authors: Renato Santos, Olga AmaralAbstract:Sphingolipidoses are inherited genetic diseases characterized by the accumulation of glycosphingolipids. Sphingolipidoses (SP), which usually involve the loss of sphingolipid hydrolase function, are of lysosomal origin, and represent an important group of rare diseases among lysosomal storage disorders. Initial treatments consisted of enzyme replacement therapy, but, in recent decades, various therapeutic approaches have been developed. However, these commonly used treatments for SP fail to be fully effective and do not penetrate the blood–brain barrier. New approaches, such as genome editing, have great potential for both the treatment and study of Sphingolipidoses. Here, we review the most recent advances in the treatment and modelling of SP through the application of CRISPR-Cas9 genome editing. CRISPR-Cas9 is currently the most widely used method for genome editing. This technique is versatile; it can be used for altering the regulation of genes involved in sphingolipid degradation and synthesis pathways, interrogating gene function, generating knock out models, or knocking in mutations. CRISPR-Cas9 genome editing is being used as an approach to disease treatment, but more frequently it is utilized to create models of disease. New CRISPR-Cas9-based tools of gene editing with diminished off-targeting effects are evolving and seem to be more promising for the correction of individual mutations. Emerging Prime results and CRISPR-Cas9 difficulties are also discussed.
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crispr cas in ipscs from Sphingolipidoses patients
Molecular Genetics and Metabolism, 2019Co-Authors: Luciana Moreira, Ana Joana Duarte, Diogo Ribeiro, Olga AmaralAbstract:Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) were found as an immune adaptive mechanism in bacteria and quickly were applied to various fields as a promising tool for gene editing. Lysosomal storage diseases (LSDs) are a group of metabolic disorders caused by defects in lysosomal proteins leading to accumulation of undigested macromolecules within the cells. The lack of good in vitro models hinders research of the pathophysiologic mechanisms and the development of new therapies. Induced pluripotent stem cells (iPSCs) are patient-specific and can be differentiated in any cell type. The advantage of iPSCs is to enable targeted studies in cells with the patient’s own background leading to more straightforward results than other models. Combining CRISPR and iPSCs is, therefore, a promising strategy. We aim to use CRISPR/Cas-mediated gene editing to provide more specific cellular models of disease, to correct causal mutations in LSDs and to create mutants for functional studies. In this work, we generated and characterized iPSCs from human fibroblasts obtained from Gaucher and Fabry patients (through Gaslini Institute) and will edit them with a CRISP/Cas9 approach. Because both gene editing and iPSCs generation require manipulating the cell’s genome, we envisage multiple check points along the workflow. It will be useful to compare the “native” mutated cells with the corrected cells that modulate the “disease in a dish”. Gene editing is still recent and the methods require improvement, namely increasing transfection rates and mutagenesis efficiency with less off-targets. Nevertheless, CRISPR/Cas is a promising alternative to other therapies, and every result contributes to the enhancement of this technology, broadening the validation of CRISPR application and making it an accessible option.
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CRISPR/Cas in iPSCs from Sphingolipidoses patients
Molecular Genetics and Metabolism, 2019Co-Authors: Luciana Moreira, Ana Joana Duarte, Diogo Ribeiro, Olga AmaralAbstract:Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) were found as an immune adaptive mechanism in bacteria and quickly were applied to various fields as a promising tool for gene editing. Lysosomal storage diseases (LSDs) are a group of metabolic disorders caused by defects in lysosomal proteins leading to accumulation of undigested macromolecules within the cells. The lack of good in vitro models hinders research of the pathophysiologic mechanisms and the development of new therapies. Induced pluripotent stem cells (iPSCs) are patient-specific and can be differentiated in any cell type. The advantage of iPSCs is to enable targeted studies in cells with the patient’s own background leading to more straightforward results than other models. Combining CRISPR and iPSCs is, therefore, a promising strategy. We aim to use CRISPR/Cas-mediated gene editing to provide more specific cellular models of disease, to correct causal mutations in LSDs and to create mutants for functional studies. In this work, we generated and characterized iPSCs from human fibroblasts obtained from Gaucher and Fabry patients (through Gaslini Institute) and will edit them with a CRISP/Cas9 approach. Because both gene editing and iPSCs generation require manipulating the cell’s genome, we envisage multiple check points along the workflow. It will be useful to compare the “native” mutated cells with the corrected cells that modulate the “disease in a dish”. Gene editing is still recent and the methods require improvement, namely increasing transfection rates and mutagenesis efficiency with less off-targets. Nevertheless, CRISPR/Cas is a promising alternative to other therapies, and every result contributes to the enhancement of this technology, broadening the validation of CRISPR application and making it an accessible option.
J Ledvinova - One of the best experts on this subject based on the ideXlab platform.
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tandem mass spectrometry of sphingolipids applications for diagnosis of Sphingolipidoses
Advances in Clinical Chemistry, 2016Co-Authors: Ladislav Kuchař, Befekadu Asfaw, Jitka Rybova, J LedvinovaAbstract:Abstract In recent years, mass spectrometry (MS) has become the dominant technology in lipidomic analysis. It is widely used in diagnosis and research of lipid metabolism disorders including those characterized by impairment of lysosomal functions and storage of nondegraded–degraded substrates. These rare diseases, which include Sphingolipidoses, have severe and often fatal clinical consequences. Modern MS methods have contributed significantly to achieve a definitive diagnosis, which is essential in clinical practice to begin properly targeted patient care. Here we summarize MS and tandem MS methods used for qualitative and quantitative analysis of sphingolipids (SL) relative to the diagnostic process for Sphingolipidoses and studies focusing on alterations in cell functions due to these disorders. This review covers the following topics: – Overview of the biochemistry of SL under normal and pathological conditions (lysosomal storage disorders, LSD) – Overview of MS and its applications to the analysis of SL: evidence of pathological storage of nondegraded SL in cells and body fluids focused on a laboratory diagnosis of LSD, isoform profiles and deacylated forms of SL as new biomarkers, applications in enzymology and metabolic experiments in living cells using mass-labeled substrates. Tandem MS is sensitive and robust in determining the composition of sphingolipid classes in various biological materials. Its ability to establish SL metabolomic profiles using MS bench-top analyzers, significantly benefits the first stages of a diagnosis as well as metabolic studies of these disorders. It can thus contribute to a better understanding of the biological significance of SL.