Mass Spectrometry Analysis of Globotriaosylsphingosine and Its Analogues in Dried Blood Spots.

Fabry disease (FD) is an X-linked lysosomal storage disorder where impaired α-galactosidase A enzyme activity leads to the intracellular accumulation of undegraded glycosphingolipids, including globotriaosylsphingosine (lyso-Gb3) and related analogues. Lyso-Gb3 and related analogues are useful biomarkers for screening and should be routinely monitored for longitudinal patient evaluation. In recent years, a growing interest has emerged in the analysis of FD biomarkers in dried blood spots (DBSs), considering the several advantages compared to venipuncture as a technique for collecting whole-blood specimens. The focus of this study was to devise and validate a UHPLC-MS/MS method for the analysis of lyso-Gb3 and related analogues in DBSs to facilitate sample collection and shipment to reference laboratories. The assay was devised in conventional DBS collection cards and in Capitainer®B blood collection devices using both capillary and venous blood specimens from 12 healthy controls and 20 patients affected with FD. The measured biomarker concentrations were similar in capillary and venous blood specimens. The hematocrit (Hct) did not affect the correlation between plasma and DBS measurements in our cohort (Hct range: 34.3-52.2%). This UHPLC-MS/MS method using DBS would facilitate high-risk screening and the follow-up and monitoring of patients affected with FD.

Metabolomic Study Using Time-of-Flight Mass Spectrometry Reveals Novel Urinary Biomarkers for Gaucher Disease Type 1.

Gaucher disease (GD) is a lysosomal storage disorder resulting from a biallelic mutation in the gene GBA1, leading to deficiencies in the enzyme ß-glucocerebrosidase (Gcase). Inabilities of the Gcase to catabolize its substrate result in the accumulation of sphingolipids in macrophages, which impairs the cell functions and ultimately leads to multisystemic clinical manifestations. Important variability in symptoms and manifestations may lead to challenging diagnosis and patient care. Plasma glucosylsphingosine (lyso-Gb1) is a biomarker frequently used for prognosis, monitoring, and patient follow-up. While lyso-Gb1 appears to be a valid biomarker, few studies have investigated other matrices for potential GD biomarkers. The main objective of this study was to investigate the urine matrix as a potential source of new GD biomarkers by performing a metabolomic study using time-of-flight mass spectrometry. Our study highlighted a significant increase of eight urinary lyso-Gb1 analogues. Moreover, a novel class of biomarkers, named polycyclic lyso-Gb1 analogues, was identified. These four new molecules were more elevated than lyso-Gb1 and related analogues in urine specimens of GD patients. Further investigations are warranted to validate the efficiency of these newly found biomarkers on a larger cohort of Gaucher patients and to compare them with plasma biomarkers currently quantified in clinical laboratories.

Vitamin B-12 Intake from Dairy but Not Meat Is Associated with Decreased Risk of Low Vitamin B-12 Status and Deficiency in Older Adults from Quebec, Canada.

BACKGROUND: Vitamin B-12 deficiency can result in irreversible neurologic damages. It is most prevalent among older adults (∼5%-15%), mainly due to impaired absorption. Vitamin B-12 bioavailability varies between food sources, so their importance in preventing deficiency may also vary. OBJECTIVES: Using the NuAge Database and Biobank, we examined the associations between vitamin B-12 intake (total and by specific food groups) and low vitamin B-12 status and deficiency in older adults. METHODS: NuAge-the Quebec Longitudinal Study on Nutrition and Successful Aging-included 1753 adults aged 67-84 y who were followed 4 y. Analytic samples comprised 1230-1463 individuals. Dietary vitamin B-12 intake was assessed annually using three 24-h dietary recalls. Vitamin B-12 status was assessed annually as low serum vitamin B-12 (<221 pmol/L), elevated urinary methylmalonic acid (MMA)/creatinine ratio (>2 µmol/mmol), and a combination of both (deficiency). Vitamin B-12 supplement users were excluded. Multilevel logistic regressions, adjusted for relevant confounders, were used. RESULTS: Across all study years, 21.8%-32.5% of participants had low serum vitamin B-12, 12.5%-17.0% had elevated urine MMA/creatinine, and 10.1%-12.7% had deficiency. Median (IQR) total vitamin B-12 intake was 3.19 µg/d (2.31-4.37). Main sources were "dairy" and "meat, poultry, and organ meats." The ORs (95% CIs) in the fifth quintile compared with the first of total vitamin B-12 intake were as follows: for low serum vitamin B-12, 0.52 (0.37, 0.75; P-trend < 0.0001); for elevated urine MMA/creatinine, 0.63 (0.37, 1.08; P-trend = 0.091); and for vitamin B-12 deficiency, 0.38 (0.18, 0.79; P-trend = 0.006). Similarly, ORs (95% CIs) in the fourth quartile compared with the first of dairy-derived vitamin B-12 intake were 0.46 (0.32, 0.66; P-trend < 0.0001), 0.51 (0.30, 0.87; P-trend = 0.006), and 0.35 (0.17, 0.73; P-trend = 0.003), respectively. No associations were observed with vitamin B-12 from "meat, poultry, and organ meats." CONCLUSIONS: Higher dietary vitamin B-12 intake, especially from dairy, was associated with decreased risk of low vitamin B-12 status and deficiency in older adults. Food groups might contribute differently at reducing risk of deficiency in older populations.

Globotriaosylsphingosine (lyso-Gb3) and analogues in plasma and urine of patients with Fabry disease and correlations with long-term treatment and genotypes in a nationwide female Danish cohort.

INTRODUCTION: Recent studies showed the usefulness of globotriaosylsphingosine (lyso-Gb3) and related analogues, deacylated forms of globotriaosylceramide (Gb3), for high-risk screening, treatment monitoring and follow-up for patients with Fabry disease. METHODS: We evaluated Gb3, lyso-Gb3 and analogues using tandem mass spectrometry in 57 women with Fabry disease followed during a period of 15.4 years. Twenty-one women were never treated and 36 received treatment (agalsidase-beta, n=30; agalsidase-alfa, n=5; or migalastat, n=1). Lyso-Gb3 and analogues at m/z (-28), (-2), (+16), (+34) and (+50) were analysed in plasma and urine. Total Gb3 and lyso-Gb3 analogues at m/z (-12) and (+14) were evaluated in urine while the analogue at m/z (+18) was evaluated in plasma. RESULTS: A strong correlation between plasma and urine lyso-Gb3 and analogue levels was revealed. Plasma and urine lyso-Gb3 and analogue levels were not statistically different between patients carrying missense (n=49), nonsense (n=6) or deletion mutations (n=2). Never treated patients had lower plasma lyso-Gb3 and analogues at m/z (-28), (-2), (+16), (+34) and the seven urinary lyso-Gb3 analogues compared with pretreatment levels of the treated patients. A significant reduction of plasma lyso-Gb3 and five analogues, as well as urine Gb3 and six lyso-Gb3 analogues, but not lyso-Gb3 and lyso-Gb3 at m/z (+50), was observed post-treatment with agalsidase-beta. The same tendency was observed with agalsidase-alfa. CONCLUSION: Women with Fabry disease who started treatment based on clinical manifestations had higher lyso-Gb3 and analogue biomarker levels than never treated women. This indicates that a biomarker cut-off could potentially be a decision tool for treatment initiation in women with Fabry disease.

Assessing the role of glycosphingolipids in the phenotype severity of Fabry disease mouse model.

Fabry disease is caused by deficient activity of α-galactosidase A, an enzyme that hydrolyzes the terminal α-galactosyl moieties from glycolipids and glycoproteins, and subsequent accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3), globotriaosylsphingosine (lyso-Gb3), and galabiosylceramide. However, there is no known link between these compounds and disease severity. In this study, we compared Gb3 isoforms (various fatty acids) and lyso-Gb3 analogs (various sphingosine modifications) in two strains of Fabry disease mouse models: a pure C57BL/6 (B6) background or a B6/129 mixed background, with the latter exhibiting more prominent cardiac and renal hypertrophy and thermosensation deficits. Total Gb3 and lyso-Gb3 levels in the heart, kidney, and dorsal root ganglion (DRG) were similar in the two strains. However, levels of the C20-fatty acid isoform of Gb3 and particular lyso-Gb3 analogs (+18, +34) were significantly higher in Fabry-B6/129 heart tissue when compared with Fabry-B6. By contrast, there was no difference in Gb3 and lyso-Gb3 isoforms/analogs in the kidneys and DRG between the two strains. Furthermore, using immunohistochemistry, we found that Gb3 massively accumulated in DRG mechanoreceptors, a sensory neuron subpopulation with preserved function in Fabry disease. However, Gb3 accumulation was not observed in nonpeptidergic nociceptors, the disease-relevant subpopulation that has remarkably increased isolectin-B4 (the marker of nonpeptidergic nociceptors) binding and enlarged cell size. These findings suggest that specific species of Gb3 or lyso-Gb3 may play major roles in the pathogenesis of Fabry disease, and that Gb3 and lyso-Gb3 are not responsible for the pathology in all tissues or cell types.

Mutation-specific Fabry disease patient-derived cell model to evaluate the amenability to chaperone therapy.

BACKGROUND: Patients with Fabry disease (FD) and amenable mutations can be treated with the chaperone migalastat to restore endogenous α-galactosidase A (AGAL) activity. However, certain amenable mutations do not respond biochemically in vivo as expected. Here, we aimed to establish a patient-specific and mutation-specific cell model to evaluate the amenability to chaperone therapy in FD. METHODS: Since current tests to determine amenability are limited to heterologous mutation expression in HEK293T cells with endogenous AGAL activity, we generated CRISPR/Cas9-mediated AGAL-deficient HEK293T cells as a basis for mutant overexpression. Furthermore, primary urinary cells from patients were isolated and immortalised as a patient-specific cell model system to evaluate the amenability to chaperone therapy. RESULTS: Under treatment (>13 months), carriers of p.N215S (n=6) showed a significant reduction of plasma lyso-Gb3 (p<0.05). Lyso-Gb3 levels in carriers of p.L294S increased (p<0.05) and two patients developed severe albuminuria. Both missense mutations were amenable in wild-type HEK293T cells (p<0.05), but presented different responses in CRISPR/Cas9-mediated AGAL knockouts and immortalised urinary cells. Chaperone incubation resulted in increased AGAL activity (p<0.0001) and intracellular globotriaosylceramide (Gb3) reduction (p<0.05) in immortalised p.N215S cells but not in p.L294S and IVS2+1 G>A cells. CONCLUSION: We conclude that repeated AGAL activity measurements in patients' white blood cells are mandatory to assess the in vivo amenability to migalastat. Plasma lyso-Gb3 might be an appropriate tool to measure the biochemical response to migalastat. Patients with low AGAL activities and increasing lyso-Gb3 levels despite in vitro amenability might not benefit sufficiently from chaperone treatment.

Identification of a Reliable Biomarker Profile for the Diagnosis of Gaucher Disease Type 1 Patients Using a Mass Spectrometry-Based Metabolomic Approach.

Gaucher disease (GD) is a rare autosomal recessive multisystemic lysosomal storage disorder presenting a marked phenotypic and genotypic variability. GD is caused by a deficiency in the glucocerebrosidase enzyme. The diagnosis of GD remains challenging because of the large clinical spectrum associated with the disease. Moreover, GD biomarkers are often not sensitive enough and can be subject to polymorphic variations. The main objective of this study was to perform a metabolomic study using an ultra-performance liquid chromatography system coupled to a time-of-flight mass spectrometer to identify novel GD biomarkers. Following the analysis of plasma samples from patients with GD, and age- and gender-matched control samples, supervised statistical analyses were used to find the best molecules to differentiate the two groups. Targeted biomarkers were structurally elucidated using accurate mass measurements and tandem mass spectrometry. This metabolomic study was successful in highlighting seven biomarkers associated with GD. Fragmentation tests revealed that these latter biomarkers were lyso-Gb1 (glucosylsphingosine) and four related analogs (with the following modifications on the sphingosine moiety: -C2H4, -H2, -H2+O, and +H2O), sphingosylphosphorylcholine, and N-palmitoyl-O-phosphocholineserine. Based on the plasma biomarker distribution, we suggest the evaluation of this GD biomarker profile, which might facilitate early diagnosis, monitoring, and follow-up of patients.

Diurnal Variation of Urinary Fabry Disease Biomarkers during Enzyme Replacement Therapy Cycles.

Fabry disease is an X-linked lysosomal storage disorder caused by mutations in the GLA gene encoding the α-galactosidase A enzyme. This enzyme cleaves the last sugar unit of glycosphingolipids, including globotriaosylceramide (Gb3), globotriaosylsphingosine (lyso-Gb3), and galabiosylceramide (Ga2). Enzyme impairment leads to substrate accumulation in different organs, vascular endothelia, and biological fluids. Enzyme replacement therapy (ERT) is a commonly used treatment. Urinary analysis of Gb3 isoforms (different fatty acid moieties), as well as lyso-Gb3 and its analogues, is a reliable way to monitor treatment. These analogues correspond to lyso-Gb3 with chemical modifications on the sphingosine moiety (-C2H4, -C2H4+O, -H2, -H2+O, +O, +H2O2, and +H2O3). The effects of sample collection time on urinary biomarker levels between ERT cycles were not previously documented. The main objective of this project was to analyze the aforementioned biomarkers in urine samples from seven Fabry disease patients (three treated males, three treated females, and one ERT-naïve male) collected twice a day (morning and evening) for 42 days (three ERT cycles). Except for one participant, our results show that the biomarker levels were generally more elevated in the evening. However, there was less variability in samples collected in the morning. No cyclic variations in biomarker levels were observed between ERT infusions.

The lysosomal enzyme alpha-Galactosidase A is deficient in Parkinson's disease brain in association with the pathologic accumulation of alpha-synuclein.

The aberrant accumulation of alpha-synuclein (α-syn) is believed to contribute to the onset and pathogenesis of Parkinson's disease (PD). The autophagy-lysosome pathway (ALP) is responsible for the high capacity clearance of α-syn. ALP dysfunction is documented in PD and pre-clinical evidence suggests that inhibiting the ALP promotes the pathological accumulation of α-syn. We previously identified the pathological accumulation of α-syn in the brains of mice deficient for the soluble lysosomal enzyme alpha-Galactosidase A (α-Gal A), a member of the glycosphingolipid metabolism pathway. In the present study, we quantified α-Gal A activity and levels of its glycosphingolipid metabolites in postmortem temporal cortex specimens from control individuals and in PD individuals staged with respect to α-syn containing Lewy body pathology. In late-state PD temporal cortex we observed significant decreases in α-Gal A activity and the 46kDa "active" species of α-Gal A as determined respectively by fluorometric activity assay and western blot analysis. These decreases in α-Gal A activity/levels correlated significantly with increased α-syn phosphorylated at serine 129 (p129S-α-syn) that was maximal in late-stage PD temporal cortex. Mass spectrometric analysis of 29 different isoforms of globotriaosylceramide (Gb3), a substrate of α-Gal A indicated no significant differences with respect to different stages of PD temporal cortex. However, significant correlations were observed between increased levels of several Gb3 isoforms and with decreased α-Gal A activity and/or increased p129S-α-syn. Deacylated Gb3 (globotriaosylsphingosine or lyso-Gb3) was also analyzed in PD brain tissue but was below the limit of detection of 20pmol/g. Analysis of other lysosomal enzymes revealed a significant decrease in activity for the lysosomal aspartic acid protease cathepsin D but not for glucocerebrosidase (GCase) or cathepsin B in late-stage PD temporal cortex. However, a significant correlation was observed between decreasing GCase activity and increasing p129S-α-syn. Together our findings indicate α-Gal A deficiency in late-stage PD brain that correlates significantly with the pathological accumulation of α-syn, and further suggest the potential for α-Gal A and its glycosphingolipid substrates as putative biomarkers for PD.

Globotriaosylsphingosine (Lyso-Gb3) as a biomarker for cardiac variant (N215S) Fabry disease.

Fabry disease (FD) is a multi-systemic X-linked lysosomal disorder caused by the deficient activity of α-galactosidase-A enzyme, which leads to accumulation of glycosphingolipids in various body tissues. The N215S mutation is a known variant of FD, with a late onset cardiac phenotype. Consensus guidelines acknowledged the use of globotriaosylsphingosine (Lyso-Gb3) as a diagnostic marker for classical FD but its utility for cardiac variant FD is not clear. We aim to characterize the clinical features and evaluate the diagnostic accuracy of plasma and urinary Lyso-Gb3 levels in N215S cardiac variant FD patients. Thirty-four FD patients with the late-onset N215S cardiac variant mutation were enrolled along with 62 classical FD patients and 109 healthy controls. Plasma and urinary Lyso-Gb3 and its analogues were analyzed by LC-MS/MS. Both FD males and females with N215S mutation showed Lyso-Gb3 levels of (mean ± SEM) 9.7 ± 1.0 and 5.4 ± 0.8 nM, respectively. These levels were significantly higher than healthy control and lower than classical FD patients (p < 0.0001). Plasma Lyso-Gb3 levels equal to or higher than 2.7 nM yielded a diagnostic sensitivity and specificity of 100% (AUC = 1, p < 0.0001). Cardiac involvement was frequent with 16/34 (47%) developing left ventricular hypertrophy. Three patients who underwent renal biopsy had the characteristic sphingolipid deposition in the podocytes while 6/19 (32%) had evidence of white matter changes or infarct on brain MRI. Taken together, cardiac variant N215S mutation is rather an attenuated form of classical FD. Plasma Lyso-Gb3 is a diagnostic hallmark to differentiate N215S variant phenotype from subjects with no FD.

Separation and Analysis of Lactosylceramide, Galabiosylceramide, and Globotriaosylceramide by LC-MS/MS in Urine of Fabry Disease Patients.

Fabry disease is an X-linked lysosomal storage disorder caused by α-galactosidase A (α-GAL A) deficiency. This enzyme contributes to the cellular recycling of glycosphingolipids such as galabiosylceramide (Ga2), globotriaosylceramide (Gb3), and globotriaosylsphingosine (lyso-Gb3) by hydrolyzing the terminal α-galactosyl moiety. Urine and plasma α-GAL A substrates are currently analyzed as biomarkers for the detection, monitoring, and follow-up of Fabry disease patients. The sensitivity of the analysis of Ga2 is decreased by the co-analysis of its structural isomer, lactosylceramide (LacCer), which is not an α-GAL A substrate. A normal-phase ultraperformance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS) methodology, allowing the baseline separation of 12 Ga2 isoforms/analogues from their lactosylceramide counterparts, was developed and validated in urine. The method was multiplexed with the analysis of 12 Gb3 isoforms/analogues having the same fatty acid moieties as those of Ga2 for comparison, and with creatinine for sample normalization. Urine samples were studied from 34 untreated and 33 Fabry males treated by enzyme replacement therapy (ERT) and 54 untreated and 19 ERT-treated Fabry females, along with 34 male and 25 female healthy controls. The chromatographic separation of Ga2 from LacCer increased the sensitivity of analysis, especially in women. One untreated Fabry female and two treated Fabry females presented abnormal levels of Ga2 but normal levels of Gb3, supporting the importance of analyzing Ga2, in addition to Gb3. Our results show that urine LacCer levels from females were significantly higher than those from males. Moreover, LacCer levels were not affected by Fabry disease for both males and females.

Tandem Mass Spectrometry Multiplex Analysis of Glucosylceramide and Galactosylceramide Isoforms in Brain Tissues at Different Stages of Parkinson Disease.

Previous studies demonstrated that Parkinson disease (PD) is associated with a decreased activity of the glucocerebrosidase (GCase) enzyme in brain tissues. The objective of this study was to determine if GCase deficiency is associated with the accumulation of its glucosylceramide (GluCer) substrate in PD brain tissues. An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed, optimized, and validated for the multiplex analysis of GluCer isoforms (C18:0, C20:0, C22:0, C24:1, and C24:0) in brain tissue samples. These molecules were chromatographically separated from their isobaric galactosylceramide (GalCer) counterparts using normal phase chromatography. The analysis was performed by tandem mass spectrometry in the multiple reaction monitoring (MRM) acquisition mode. Limits of detection ranging from 0.4 to 1.1 nmol/g brain tissue were established for the different GluCer isoforms analyzed. For the first time, GluCer isoform levels were analyzed in temporal cortex brain tissue samples from 26 PD patients who were divided into three PD disease stages (IIa, III, and IV) according to the Unified Staging System for Lewy Body Disorders. These specimens were compared with brain tissue samples from 12 controls and 6 patients with Incidental Lewy Body Disease. No significant GluCer concentration differences were observed between the 5 sample groups. The GluCer isoform levels were also normalized with their matching GalCer isoforms. The normalized results showed a trend for GluCer levels which increased with PD severity. However, the differences observed between the groups were not significant, owing likely to the high standard deviations measured.

Multiplex tandem mass spectrometry analysis of novel plasma lyso-Gb3-related analogues in Fabry disease.

Fabry disease is a multisystemic, X-linked lysosomal storage disorder caused by a deficit in α-galactosidase A enzyme activity leading to glycosphingolipid accumulation, mainly globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3). Recent metabolomic studies have led to the discovery of novel biomarkers related to lyso-Gb3 in plasma and urine. These biomarkers show modifications of the sphingosine moiety of the lyso-Gb3 molecule. The objectives of this study were to develop and validate a liquid chromatography-tandem mass spectrometry method for the relative quantification of novel plasma lyso-Gb3-related analogues, to evaluate their levels in plasma of 74 Fabry patients and 41 healthy controls and to correlate these results with patient gender, enzyme replacement therapy treatment, and lyso-Gb3 analogue levels previously measured in urine for the same patients. As expected, the concentrations of lyso-Gb3 and its related analogues in plasma are higher in Fabry males compared to Fabry females and higher for untreated males compared to treated males. The concentration of lyso-Gb3 and its related analogues in plasma decrease significantly after the beginning of enzyme replacement therapy (ERT) treatment and remain stable for 30 months of monitored therapy in a Fabry male. In plasma, lyso-Gb3 is significantly more abundant than its related analogues, which differs from urine where the majority of the lyso-Gb3 analogues are more increased than lyso-Gb3 itself. In contrast to urine, the relative distribution of lyso-Gb3 and its analogues in plasma is similar from one individual to another in the same group of Fabry patients, irrespective of ERT. This study revealed a large discrepancy between the relative abundance of lyso-Gb3 and its analogues in urine and plasma. Further studies will thus be needed to better understand the metabolic relationship between plasma and urine lyso-Gb3-related biomarkers.

Quantitative proteomics profiling of the poly(ADP-ribose)-related response to genotoxic stress.

Upon DNA damage induction, DNA-dependent poly(ADP-ribose) polymerases (PARPs) synthesize an anionic poly(ADP-ribose) (pADPr) scaffold to which several proteins bind with the subsequent formation of pADPr-associated multiprotein complexes. We have used a combination of affinity-purification methods and proteomics approaches to isolate these complexes and assess protein dynamics with respect to pADPr metabolism. As a first approach, we developed a substrate trapping strategy by which we demonstrate that a catalytically inactive Poly(ADP-ribose) glycohydrolase (PARG) mutant can act as a physiologically selective bait for the isolation of specific pADPr-binding proteins through its macrodomain-like domain. In addition to antibody-mediated affinity-purification methods, we used a pADPr macrodomain affinity resin to recover pADPr-binding proteins and their complexes. Second, we designed a time course experiment to explore the changes in the composition of pADPr-containing multiprotein complexes in response to alkylating DNA damage-mediated PARP activation. Spectral count clustering based on GeLC-MS/MS analysis was complemented with further analyses using high precision quantitative proteomics through isobaric tag for relative and absolute quantitation (iTRAQ)- and Stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics. Here, we present a valuable resource in the interpretation of systems biology of the DNA damage response network in the context of poly(ADP-ribosyl)ation and provide a basis for subsequent investigations of pADPr-binding protein candidates.

Analysis of Globotriaosylceramide (Gb3) in Liquid Urine: A Straightforward Assay Using Tandem Mass Spectrometry.

Fabry disease (FD) is a lysosomal storage disorder caused by variants in the GLA gene encoding α-galactosidase A, an enzyme required for catabolism of globotriaosylceramide (Gb3). Accumulation of Gb3 in patients' cells, tissues, and biological fluids causes clinical manifestations including ventricular hypertrophy, renal insufficiency, and strokes. This protocol describes a methodology to analyze urinary Gb3 and creatinine. Samples are diluted with an internal standard solution containing Gb3(C17:0) and creatinine-D3, centrifuged, and directly analyzed by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) using an 8.7-min method. Eight Gb3 isoforms [C16:0, C18:0, C20:0, C22:1, C22:0, C24:1, C24:0, and (C24:0)OH] are analyzed and the total is normalized to creatinine. Confirmation ions are monitored to detect potential interferences. The Gb3 limit of quantification is 0.023 µg/ml. Its interday coefficients of variation (3 concentrations measured) are ≤15.4%. This method minimizes matrix effects (≤6.5%) and prevents adsorption or precipitation of Gb3. Urine samples are stable (bias <15%) for 2 days at 21°C, 7 days at 4°C, and 4 freeze/thaw cycles, whereas prepared samples are stable for 5 days at 21°C, and 14 days at 4°C. The Gb3/creatinine age-related upper reference limits (mean + 2 standard deviations) are 29 mg/mol creatinine (<7 years) and 14 mg/mol creatinine (≥7 years). This simple, robust protocol has been fully validated (ISO 15189) and provides a valuable tool for diagnosis and monitoring of FD patients. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol: Analysis of urinary globotriaosylceramide (Gb3) and creatinine by UHPLC-MS/MS Support Protocol 1: Preparation of the urinary quality controls Support Protocol 2: Preparation of the urine matrix used for the Gb3 calibration curve Support Protocol 3: Preparation of the Gb3 calibrators Support Protocol 4: Preparation of the working solution containing the internal standards Support Protocol 5: Preparation of the creatinine calibrators Support Protocol 6: Preparation of the UHPLC solutions and mobile phases.

A metabolomic study to identify new globotriaosylceramide-related biomarkers in the plasma of Fabry disease patients.

Fabry disease is an X-linked lysosomal storage disorder caused by a deficiency of the enzyme α-galactosidase A, which results in the progressive accumulation of glycosphingolipids. In addition to the two biomarkers, globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3), which are routinely used for detection and high-risk screening of Fabry disease patients, novel urinary Gb3-related isoforms/analogues as well as newly defined lyso-Gb3 analogues in plasma and urine from Fabry patients have recently been described by our group. The aim of this study was to extend our recent analyses to identify and evaluate new potential Gb3-related biomarkers in the plasma of untreated male Fabry disease patients using a mass spectrometry metabolomic approach. A multivariate statistical analysis revealed five Gb3-related novel biomarkers in the plasma of male Fabry patients. Three of these new biomarkers correspond to Gb3, which has an extra double bond on the sphingosine with C16:0, C18:0, and C22:1 fatty acid chains. The fourth biomarker corresponds to a mixture of two structural isomers, the first with a d16:1 sphingosine and a C16:0 fatty acid and the second with a d18:1 sphingosine and a C14:0 fatty acid. To our knowledge, it is the first time that a Gb3 analogue with a d16:1 sphingosine moiety has been reported. In addition, this Gb3 analogue was also present in its methylated form. These biomarkers are part of a metabolic profile that may provide insight into the pathophysiology of Fabry disease.

Multiplex analysis of novel urinary lyso-Gb3-related biomarkers for Fabry disease by tandem mass spectrometry.

Fabry disease is a lysosomal storage disorder caused by the absence or reduction of α-galactosidase A enzyme activity. The enzymatic deficiency results in the impaired catabolism of neutral sphingolipids with terminal α-galactosyl residues and subsequent accumulation in several tissues. Biomarkers reflecting disease severity and progression, the response to therapeutic intervention, and details of molecular pathogenesis are needed. Until now, two sphingolipids were targeted as biomarkers in urine and plasma of Fabry patients: globotriaosylceramide (Gb(3)) and globotriaosylsphingosine (lyso-Gb(3)). Using metabolomic approaches, our group recently discovered seven novel urinary lyso-Gb(3)-related Fabry disease biomarkers with mass-to-charge ratios (m/z) of 758, 774, 784, 800, 802, 820, and 836. All these biomarkers exhibited modifications of the lyso-Gb(3) sphingosine moiety. The aims of the present study were to devise and validate a specific tandem mass spectrometry multiplex methodology for the relative quantification of these seven analogues and to evaluate their urinary excretion levels in samples from 164 Fabry patients and 94 healthy controls. We found no detectable analogues in healthy controls, except for trace amounts of the analogue with m/z 836. Significant correlations were established between lyso-Gb(3) analogue levels in urine and gender (p < 0.001). Fabry males had higher excretion levels compared to females with the disease. Lyso-Gb(3) analogue levels correlated well with enzyme replacement therapy (ERT) status in males (p < 0.05). The urinary analogue distributions varied among Fabry patients. However, the analogues with m/z 802, 820, and 836 were generally more abundant in the majority of patients. Lyso-Gb(3) analogues are promising urinary biomarkers for Fabry disease.

Multiplex Quantification of Plasma Biomarkers for Patients with Gaucher Disease Type 1.

Gaucher disease (GD) is a lysosomal storage disorder caused by a deficiency of the enzyme beta-glucocerebrosidase. This leads to the accumulation of glycolipids in macrophages and ultimately results in tissue damage. Recent metabolomic studies highlighted several potential biomarkers in plasma specimens. In hopes of better understanding the distribution, importance, and clinical significance of these potential markers, a UPLC-MS/MS method was developed and validated to quantify lyso-Gb1 and six related analogs (with the following modifications on the sphingosine moiety: -C2 H4 (-28 Da), -C2 H4 +O (-12 Da), -H2 (-2 Da), -H2 +O (+14 Da), +O (+16 Da), and +H2 O (+18 Da)), sphingosylphosphorylcholine, and N-palmitoyl-O-phosphocholineserine in plasma specimens of treated and untreated patients. This 12-min UPLC-MS/MS method involves a purification step via solid-phase extraction followed by evaporation under nitrogen flow and resuspension in an organic mix compatible with HILIC chromatography. This method is currently used for research purposes and might be used for monitoring, prognostics, and follow-up. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC.

Urinary globotriaosylsphingosine-related biomarkers for Fabry disease targeted by metabolomics.

Fabry disease is a lysosomal storage disorder caused by deficiency of α-galactosidase A, resulting in glycosphingolipid accumulation in organs and tissues, including plasma and urine. Two disease-specific Fabry biomarkers have been identified and quantified in plasma and urine: globotriaosylceramide (Gb(3)) and globotriaosylsphingosine (lyso-Gb(3)). The search continues for biomarkers that might be reliable indicators of disease severity and response to treatment. The main objective of this study was to target other urinary biomarkers using a time-of-flight mass spectrometry metabolomic approach. Urinary metabolites of 63 untreated Fabry patients and 59 controls were analyzed. A multivariate statistical analysis performed on a subset of male samples revealed seven novel Fabry biomarkers in urine, all lyso-Gb(3) analogues having modified sphingosine moieties. The empirical formulas of the sphingosine modifications were determined by exact mass measurements (- C(2)H(4), - C(2)H(4) + O, - H(2), - H(2) + O, + O, + H(2)O(2), + H(2)O(3)). We evaluated the relative concentration of lyso-Gb(3) and its seven analogues by measuring area counts for each analogue in all Fabry patients. All samples were normalized to creatinine. We found higher concentrations for males with Fabry disease compared to females. None of these biomarkers were detected in controls. To our knowledge, this is the first time that lyso-Gb(3)-related Fabry disease biomarkers are detected in urine.