GLA-modified RNA treatment lowers GB3 levels in iPSC-derived cardiomyocytes from Fabry-affected individuals.

Recent studies in non-human model systems have shown therapeutic potential of nucleoside-modified messenger RNA (modRNA) treatments for lysosomal storage diseases. Here, we assessed the efficacy of a modRNA treatment to restore the expression of the galactosidase alpha (GLA), which codes for α-Galactosidase A (α-GAL) enzyme, in a human cardiac model generated from induced pluripotent stem cells (iPSCs) derived from two individuals with Fabry disease. Consistent with the clinical phenotype, cardiomyocytes from iPSCs derived from Fabry-affected individuals showed accumulation of the glycosphingolipid Globotriaosylceramide (GB3), which is an α-galactosidase substrate.

Endogenous, non-reducing end glycosaminoglycan biomarkers for the mucopolysaccharidoses: Accurate diagnosis and elimination of false positive newborn screening results.

The mucopolysaccharidoses (MPS) are a family of inborn errors of metabolism resulting from a deficiency in a lysosomal hydrolase responsible for the degradation of glycosaminoglycans (GAG). From a biochemical standpoint, excessive urinary excretion of GAG has afforded first-tier laboratory investigations for diagnosis whereas newborn screening programs employ lysosomal hydrolase measurements. Given false positives are not uncommon, second-tier diagnostic testing relies on lysosomal hydrolase measurements following elevated urinary GAG, and newborn screening results are often corroborated with GAG determinations.

Spinal muscular atrophy-like phenotype in a mouse model of acid ceramidase deficiency.

Mutations in ASAH1 have been linked to two allegedly distinct disorders: Farber disease (FD) and spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME). We have previously reported FD-like phenotypes in mice harboring a single amino acid substitution in acid ceramidase (ACDase), P361R, known to be pathogenic in humans (P361R-Farber). Here we describe a mouse model with an SMA-PME-like phenotype (P361R-SMA).

Elevation of gangliosides in four brain regions from Parkinson's disease patients with a GBA mutation.

A number of genetic risk factors have been identified over the past decade for Parkinson's Disease (PD), with variants in GBA prominent among them. GBA encodes the lysosomal enzyme that degrades the glycosphingolipid, glucosylceramide (GlcCer), with the activity of this enzyme defective in Gaucher disease. Based on the ill-defined relationship between glycosphingolipid metabolism and PD, we now analyze levels of various lipids by liquid chromatography/electrospray ionization-tandem mass spectrometry in four brain regions from age- and sex-matched patient samples, including idiopathic PD, PD patients with a GBA mutation and compare both to control brains (n = 21 for each group) obtained from individuals who died from a cause unrelated to PD.

Impaired neural differentiation of MPS IIIA patient induced pluripotent stem cell-derived neural progenitor cells.

Mucopolysaccharidosis type IIIA (MPS IIIA) is characterised by a progressive neurological decline leading to early death. It is caused by bi-allelic loss-of-function mutations in encoding sulphamidase, a lysosomal enzyme required for heparan sulphate glycosaminoglycan (HS GAG) degradation, that results in the progressive build-up of HS GAGs in multiple tissues most notably the central nervous system (CNS). Skin fibroblasts from two MPS IIIA patients who presented with an intermediate and a severe clinical phenotype, respectively, were reprogrammed into induced pluripotent stem cells (iPSCs).

Experience with the Urinary Tetrasaccharide Metabolite for Pompe Disease in the Diagnostic Laboratory.

Following clinical indications, the laboratory diagnosis of the inherited metabolic myopathy, Pompe disease (PD), typically begins with demonstrating a reduction in acid alpha-glucosidase (GAA), the enzyme required for lysosomal glycogen degradation. Although simple in concept, a major challenge is defining reference intervals, as even carriers can have reduced GAA, and pseudodeficiencies complicate interpretation. Here, we developed a mass spectrometric assay for quantification of a urinary glycogen metabolite (tetrasaccharide) and reported on its utility as a confirmatory test for PD in a diagnostic laboratory.

Systemic scAAV9.U1a.hSGSH Delivery Corrects Brain Biochemistry in Mucopolysaccharidosis Type IIIA at Early and Later Stages of Disease.

Mucopolysaccharidosis type IIIA (MPS IIIA, Sanfilippo A syndrome) is a single gene () childhood onset neurodegenerative disease for which gene therapy is in clinical trial. Theoretically, the transfer of a working gene should enable functional expression of the defective protein and rescue the phenotype when administered before the onset of irreversible disease. Recombinant adeno-associated virus (AAV) is being used as a vehicle for a number of gene therapy applications and the neurotropism of serotype 9 affords utility for monogenetic neurological disorders.

Chondroitin sulfate disaccharide is a specific and sensitive biomarker for mucopolysaccharidosis type IVA.

Mucopolysaccharidosis type IVA (MPS IVA) is an inborn error of glycosaminoglycan (GAG) catabolism characterized by a deficiency of the lysosomal enzyme, -acetylgalactosamine 6-sulphatase (GALNS). Consequently, partially degraded GAG, chondroitin 6-sulfate (CS) and keratan sulfate (KS), accumulate in the lysosomes of affected cells, primarily in cartilage resulting in skeletal disease. Excessive urinary excretion of these GAG is often used as the initial biochemical parameter to inform a laboratory diagnosis.

Increased monohexosylceramide levels in the serum of established rheumatoid arthritis patients.

Objectives: To identify serum sphingolipids that could act as candidate biomarkers in RA.

Methods: We performed lipidomic analyses in the serum of 82 participants: 19 established RA patients, 18 untreated early RA patients, 13 untreated early arthritis patients not fulfilling the classification criteria for RA, 12 established SpA patients and 20 controls. We compared the lipid levels from the different patient groups with the control group through multiple-regression analyses controlling for age at diagnosis, gender and medication (cDMARDs and corticoids).

Expanding the clinical utility of glucosylsphingosine for Gaucher disease.

Gaucher disease (GD) is an inherited metabolic disorder characterised by impaired catabolism of the glycosphingolipid, glucosylceramide. The deacetylated derivative, glucosylsphingosine (GluSph, lyso-Gb1) has materialised as a biomarker for GD. Further appraisal of the clinical utility of GluSph is required in terms of its prognostic power to inform disease course and pre-symptomatic testing.

Sphingolipid dyshomeostasis in the brain of the mouse model of mucopolysaccharidosis type IIIA.

Gangliosides are complex glycosphingolipids that are vital for proper brain development and function. Alterations in ganglioside metabolism are evident in neurological disorders including the inherited metabolic disease mucopolysaccharidosis type IIIA (MPS IIIA/Sanfilippo A syndrome). Here we sought to comprehensively analyse alterations in ganglioside metabolism within the brain of a naturally occurring MPS IIIA mouse model at early (one month) and late (six months of age) stages of disease progression, as well as the impact on related sphingolipids in the ganglioside metabolic pathway.

Collection of cerebrospinal fluid from murine lateral ventricles for biomarker determination in mucopolysaccharidosis type IIIA.

Background: Cerebrospinal fluid (CSF) collection is currently the only feasible means to obtain biological fluid for the quantitative determination of biomarkers that may reflect disease activity within the brain. Studies in mouse models of human neurological disease benefit from ascertainment and subsequent analysis of brain tissue that is not afforded in human patients. The CSF provides a translational forum, however, due to the practical constraints presented by the mouse's small size, CSF is often ignored in experimental mouse models.

Evaluation of biomarkers for Sanfilippo syndrome.

Sanfilippo syndrome or mucopolysaccharidosis type III (MPS III) is a childhood metabolic disorder marked by neuropathology arising due to impaired heparan sulphate (HS) catabolism. Consequently, partially degraded HS accumulates in the lysosomes of affected cells and is excreted in the urine. The measurement of HS in urine has long been considered a biomarker of Sanfilippo syndrome although it is largely non-specific.

Disease and subtype specific signatures enable precise diagnosis of the mucopolysaccharidoses.

Purpose: Expanding treatments for the mucopolysaccharidoses-a family of genetic disorders-place unprecedented demands for accurate, timely diagnosis because best outcomes are seen with early initiation of appropriate therapies. Here we sought to improve the diagnostic odyssey by measuring specific glycosaminoglycan fragments with terminal residues complicit with the genetic defect resulting in precise diagnosis rather than the usual first-line, ambiguous total glycosaminoglycan determinations that return poor diagnostic yield.

Methods: A derivatizing reagent was added to urine aliquots (0.

Maternal overnutrition by hypercaloric diets programs hypothalamic mitochondrial fusion and metabolic dysfunction in rat male offspring.

Background: Maternal overnutrition including pre-pregnancy, pregnancy and lactation promotes a lipotoxic insult leading to metabolic dysfunction in offspring. Diet-induced obesity models (DIO) show that changes in hypothalamic mitochondria fusion and fission dynamics modulate metabolic dysfunction. Using three selective diet formula including a High fat diet (HFD), Cafeteria (CAF) and High Sugar Diet (HSD), we hypothesized that maternal diets exposure program leads to selective changes in hypothalamic mitochondria fusion and fission dynamics in male offspring leading to metabolic dysfunction which is exacerbated by a second exposure after weaning.

Mass spectrometry-directed structure elucidation and total synthesis of ultra-long chain (-acyl)-ω-hydroxy fatty acids.

The (-acyl)-ω-hydroxy FAs (OAHFAs) comprise an unusual lipid subclass present in the skin, vernix caseosa, and meibomian gland secretions. Although they are structurally related to the general class of FA esters of hydroxy FAs (FAHFAs), the ultra-long chain (30-34 carbons) and the putative ω-substitution of the backbone hydroxy FA suggest that OAHFAs have unique biochemistry. Complete structural elucidation of OAHFAs has been challenging because of their low abundance within complex lipid matrices.

Glycosaminoglycan fragments as a measure of disease burden in the mucopolysaccharidosis type I mouse.

Glycosaminoglycan (GAG) catabolism involves endo-hydrolysis of polysaccharides followed by the sequential removal of the non-reducing end residue from the resulting oligosaccharides by exo-enzymes. In the inherited metabolic disorder, mucopolysaccharidosis type I (MPS I), a deficiency in the exo-enzyme, α-l-iduronidase, prevents removal of α-l-iduronic acid residues from the non-reducing end of the GAGs, heparan sulphate (HS) and dermatan sulphate (DS). The excretion of partially degraded HS and DS in urine of MPS I patients has long been recognized, but the question of whether they do indeed reflect GAG load in a particular tissue has not been addressed - an important issue in the context of biomarkers for assessment of disease burden in MPS I.

Reduced cerebral vascularization in experimental neuronopathic Gaucher disease.

The glycosphingolipidosis, Gaucher disease, in which a range of neurological manifestations occur, results from a deficiency of acid β-glucocerebrosidase, with subsequent accumulation of β-glucocerebroside, its upstream substrates, and the non-acylated congener β-glucosylsphingosine. However, the mechanisms by which end-organ dysfunction arise are poorly understood. Here, we report strikingly diminished cerebral microvascular density in a murine model of disease, and provide a detailed analysis of the accompanying cerebral glycosphingolipidome in these animals, with marked elevations of β-glucosylsphingosine.

Subregional brain distribution of simple and complex glycosphingolipids in the mucopolysaccharidosis type I (Hurler syndrome) mouse: impact of diet.

Gangliosides are the most complex oligosaccharide-containing glycosphingolipids defined by the presence of sialic acid and although present in all tissues, predominate in the brain. Considering their importance in neural development, it is unsurprising that ganglioside metabolism is altered in neurodegenerative diseases. The severe form of mucopolysaccharidosis type I, Hurler syndrome (HS), is characterised by progressive loss of neuronal function through largely undefined mechanisms.

Quantification of plasma sulfatides by mass spectrometry: Utility for metachromatic leukodystrophy.

Impaired sulfatide catabolism is the primary biochemical insult in patients with the inherited neurodegenerative disease, metachromatic leukodystrophy (MLD), and sulfatide elevation in body fluids is useful in the diagnostic setting. Here we used mass spectrometry to quantify fourteen species of sulfatide, in addition to the deacetylated derivative, lyso-sulfatide, using high pressure liquid chromatography-electrospray ionisation-tandem mass spectrometry in both positive and negative ion mode. A single phase extraction of 0.

Determination of ester position in isomeric (O-acyl)-hydroxy fatty acids by ion trap mass spectrometry.

Rationale: (O-acyl)-hydroxy fatty acids (OAHFAs) are a recently discovered class of endogenous lipids, generating significant interest for their correlation with enhanced glucose tolerance. Structural variants that differ in the position of the ester linkage have been described, including the ω-OAHFA sub-class, that plays a key role in stabilizing the human tear film. Developing analytical tools for rapid and unambiguous structural elucidation of OAHFAs is essential to understanding their diverse physiological functions.

Selective normalisation of regional brain bis(monoacylglycero)phosphate in the mucopolysaccharidosis 1 (Hurler) mouse.

Bis(monoacylglycero)phosphate (BMP) is a glycerophospholipid highly enriched in the lysosomal network and elevated in lysosomal diseases. To correct this elevation, BMP synthesis was manipulated by dietary fatty acid supplementation and the impact on subregional brain BMP and pathology assessed in the mouse model of mucopolysaccharidosis 1 (Hurler syndrome (HS)). There was widespread elevation of BMP in HS mice across all six sub-regions - brain stem, cortex, cerebellum, hippocampus, olfactory bulb and the sub-cortex - with 22:6/22:6 the most abundant species.

Ceramide accumulation in L6 skeletal muscle cells due to increased activity of ceramide synthase isoforms has opposing effects on insulin action to those caused by palmitate treatment.

Aims/hypothesis: An accumulation of ceramides has been implicated in the generation of insulin resistance in skeletal muscle upon an oversupply of fatty acid. Different ceramide species are generated through the actions of ceramide synthases (CerSs), which incorporate specific acyl side chains. We tested whether particular CerS isoforms promoted insulin resistance through the generation of more inhibitory ceramide species, thus representing potential targets for intervention.