Nano-LC-MS/MS for Quantification of Lyso-Gb3 and Its Analogues Reveals a Useful Biomarker for Fabry Disease

Profiles of Globotriaosylsphingosine Analogs and Globotriaosylceramide Isoforms Accumulated in Body Fluids from Various Phenotypic Fabry Patients

Objectives Fabry disease is characterized by the systemic accumulation of globotriaosylceramide (Gb3) and globotriaosylsphingosine (Lyso-Gb3), which are widely used as biomarkers of the disease. However, few reports have described the relationship of Lyso-Gb3 analogs and Gb3 isoforms with the disease. The present study determined the profiles of Lyso-Gb3 analogs and Gb3 isoforms accumulated in body fluids from various phenotypic Fabry patients to elucidate the basis of the disease. Methods Plasma Lyso-Gb3 and related analogs were measured in 15 classic Fabry men, 6 later-onset Fabry men, 11 Fabry women, and 36 controls, while urinary Gb3 isoforms were measured in 5 classic Fabry men, 5 later-onset Fabry men, 17 Fabry women, and 11 controls, using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Furthermore, these values were monitored for a classic Fabry man, in whom neutralizing anti-drug antibodies had developed following enzyme replacement therapy (ERT). Results The levels of plasma Lyso-Gb3 analogs/urinary Gb3 isoforms were higher in Fabry patients than in controls, especially in classic Fabry men. However, minor differences in the ratio of each Lyso-Gb3 analog and Gb3 isoform with respect to the total Lyso-Gb3 analogs and Gb3 isoforms, respectively, were observed among individual classic Fabry men. Their time courses were well associated with the development and attenuation of anti-drug antibodies in a patient with classic Fabry disease during ERT. Conclusion Quantification of Lyso-Gb3 analogs and Gb3 isoforms provides us with more detailed information about the substrates that accumulated in the body fluids of Fabry patients than does quantification of Lyso-Gb3 and Gb3 alone, so this approach may be useful for elucidating the basis of Fabry disease.

Does administration of hydroxychloroquine/amiodarone affect the efficacy of enzyme replacement therapy for Fabry mice?

As a standard therapy for Fabry disease, enzyme replacement therapy (ERT) with recombinant human α-galactosidase A (α-Gal) has been successfully used, and the instructions for this drug state that "it should not be co-administrated with cationic amphiphilic drugs such as hydroxychloroquine (HCQ) and amiodarone (AMI), since these drugs have the potential to inhibit intracellular α-Gal activity". However, there would be cases in which HCQ or AMI is required for patients with Fabry disease, considering their medical efficacy and application. Thus, we examined the impact of HCQ/AMI on recombinant human α-Gal by in vitro, cellular, and animal experiments. The results revealed that HCQ/AMI affected the enzyme activity of α-Gal incorporated into cultured fibroblasts from a Fabry mouse when the cells were cultured in medium containing these drugs and the enzyme, although their direct inhibitory effect on the enzyme is not strong. These lysosomotropic drugs may be trapped and concentrated in lysosomes, followed by inhibition of α-Gal. On the other hand, no reduction of α-Gal activity incorporated into the organs and tissues, or acceleration of glycoshingolipid accumulation was observed in Fabry mice co-administered with HCQ/AMI and the enzyme, compared with in the case of usual ERT. As HCQ/AMI administered are catabolized in the liver, these drugs possibly do not affect ERT for Fabry mice, different from in the case of cultured cells in an environment isolated from the surroundings.

Fabry Disease in Women: Genetic Basis, Available Biomarkers, and Clinical Manifestations

Fabry Disease (FD) is a rare lysosomal storage disorder caused by mutations in the GLA gene on the X chromosome, leading to a deficiency in α-galactosidase A (AGAL) enzyme activity. This leads to the accumulation of glycosphingolipids, primarily globotriaosylceramide (Gb3), in vital organs such as the kidneys, heart, and nervous system. While FD was initially considered predominantly affecting males, recent studies have uncovered that heterozygous Fabry women, carrying a single mutated GLA gene, can manifest a wide array of clinical symptoms, challenging the notion of asymptomatic carriers. The mechanisms underlying the diverse clinical manifestations in females remain not fully understood due to X-chromosome inactivation (XCI). XCI also known as "lyonization", involves the random inactivation of one of the two X chromosomes. This process is considered a potential factor influencing phenotypic variation. This review delves into the complex landscape of FD in women, discussing its genetic basis, the available biomarkers, clinical manifestations, and the potential impact of XCI on disease severity. Additionally, it highlights the challenges faced by heterozygous Fabry women, both in terms of their disease burden and interactions with healthcare professionals. Current treatment options, including enzyme replacement therapy, are discussed, along with the need for healthcare providers to be well-informed about FD in women, ultimately contributing to improved patient care and quality of life.

Abnormal Pre-mRNA Splicing in Exonic Fabry Disease-Causing GLA Mutations

Fabry disease (FD) is a rare X-linked disease due to a multiverse of disrupting mutations within the GLA gene encoding lysosomal α-galactosidase A (AGAL). Absent AGAL activity causes the accumulation of complex glycosphingolipids inside of lysosomes in a variety of cell types and results in a progressive multisystem disease. Known disease-associated point mutations in protein-coding gene regions usually cause translational perturbations and result in premature chain termination, punctual amino acid sequence alterations or overall altered sequence alterations downstream of the mutation site. However, nucleotide exchanges at the border between introns and exons can affect splicing behavior and lead to abnormal pre-mRNA processing. Prediction with the Human Splicing Finder (HSF) revealed an indication of a significant change in splicing-relevant information for some known FD-associated GLA mutations. To experimentally determine the extent of the change, we made use of a minigene reporter assay and verified alternative splicing events for the exonic mutations c.194G>T and c.358C>G, which led to the usage of alternative donor splice sites at exon 1 and exon 2, respectively. In addition, the mutations c.548G>T and c.638A>T led to significant exon 4 skipping. We conclude that splicing phenotype analysis should be employed in the in vitro analysis of exonic GLA gene mutations, since abnormal splicing may result in a reduction of enzyme activity and alter the amenability for treatment with pharmacological chaperone (PC).

Metabolic Fingerprinting of Fabry Disease: Diagnostic and Prognostic Aspects

Fabry disease (FD) is an X-linked lysosomal disease due to a deficiency in the activity of the lysosomal-galactosidase A (GalA), a key enzyme in the glycosphingolipid degradation pathway. FD is a complex disease with a poor genotype–phenotype correlation. In the early stages, FD could involve the peripheral nervous system (acroparesthesias and dysautonomia) and the ski (angiokeratoma), but later kidney, heart or central nervous system impairment may significantly decrease life expectancy. The advent of omics technologies offers the possibility of a global, integrated and systemic approach well-suited for the exploration of this complex disease. In this narrative review, we will focus on the main metabolomic studies, which have underscored the importance of detecting biomarkers for a diagnostic and prognostic purpose in FD. These investigations are potentially useful to explain the wide clinical, biochemical and molecular heterogeneity found in FD patients. Moreover, the quantitative mass spectrometry methods developed to evaluate concentrations of these biomarkers in urine and plasma will be described. Finally, the complex metabolic biomarker profile depicted in FD patients will be reported, which varies according to gender, types of mutations, and therapeutic treatment.

The 30-year Natural History of Non-classic Fabry Disease with an R112H Mutation

Fabry disease is a rare X-linked lysosomal storage disorder caused by mutations in the alpha-galactosidase A (GLA) gene that results in deficiency of the enzyme GLA and leads to the accumulation of globotriaosylceramide (GL-3) in cells. The accumulation of GL-3 may lead to life-threatening complications. Significant advances in genetic sequencing technology have led to a better understanding of genotype-phenotype interactions in Fabry disease. Fabry disease with an R112H mutation is known as the non-classic type. However, the long-term clinical course of the disease remains unknown. We herein report a patient with a 30-year natural history of non-classic Fabry disease with an R112H mutation.

Screening of Fabry disease in patients with chronic kidney disease in Japan

BACKGROUND

Fabry disease (FD), an X-linked lysosomal storage disorder caused by a deficiency in alfa-galactosidase A (α-Gal A) activity due to mutations in the GLA gene, has a prevalence of 0-1.69% in patients undergoing haemodialysis; however, its prevalence in patients with chronic kidney disease (CKD) Stages 1-5 is unknown.

METHODS

Serum α-Gal A activity analysis and direct sequencing of GLA were used to screen for FD in 2122 male patients with CKD, including 1703 patients with CKD Stage 5D and 419 with CKD Stages 1-5. The correlation between serum α-Gal A activity and confounding factors in patients with CKD Stages 1-5 was evaluated.

RESULTS

FD prevalence rates in patients with CKD Stage 5D and CKD Stages 1-5 were 0.06% (1/1703) and 0.48% (2/419), respectively. A patient with CKD Stage 5D exhibited a novel GLA mutation, p.Met208Arg, whereas two patients with CKD Stages 1-5 had c.370delG and p.Met296Ile. p. Met208Arg caused moderate structural changes in the molecular surface region near the substituted amino acid residue but did not affect the catalytic residues Asp170 and Asp231 in α-Gal A. Serum α-Gal A activity in patients with CKD Stages 1-5 was inversely correlated with age (P < 0.0001) but directly correlated with estimated glomerular filtration rate (P < 0.0001).

CONCLUSIONS

FD prevalence was much higher in male patients with CKD Stages 1-5 than in those with CKD Stage 5D. FD screening in patients with CKD Stages 1-5 may improve patient survival, decreasing the number of patients with CKD Stage 5D.

A Rapid and Simple UHPLC-MS/MS Method for Quantification of Plasma Globotriaosylsphingosine (lyso-Gb3)

Fabry disease (FD) is a rare X-linked lysosomal storage disorder caused by α-galactosidase A gene (GLA) mutations, resulting in loss of activity of the lysosomal hydrolase, α-galactosidase A (α-Gal A). As a result, the main glycosphingolipid substrates, globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3), accumulate in plasma, urine, and tissues. Here, we propose a simple, fast, and sensitive method for plasma quantification of lyso-Gb3, the most promising secondary screening target for FD. Assisted protein precipitation with methanol using Phree cartridges was performed as sample pre-treatment and plasma concentrations were measured using UHPLC-MS/MS operating in MRM positive electrospray ionization. Method validation provided excellent results for the whole calibration range (0.25–100 ng/mL). Intra-assay and inter-assay accuracy and precision (CV%) were calculated as <10%. The method was successfully applied to 55 plasma samples obtained from 34 patients with FD, 5 individuals carrying non-relevant polymorphisms of the GLA gene, and 16 healthy controls. Plasma lyso-Gb3 concentrations were larger in both male and female FD groups compared to healthy subjects (p < 0.001). Normal levels of plasma lyso-Gb3 were observed for patients carrying non-relevant mutations of the GLA gene compared to the control group (p = 0.141). Dropping the lower limit of quantification (LLOQ) to 0.25 ng/mL allowed us to set the optimal plasma lyso-Gb3 cut-off value between FD patients and healthy controls at 0.6 ng/mL, with a sensitivity of 97.1%, specificity of 100%, and accuracy of 0.998 expressed by the area under the ROC curve (C.I. 0.992 to 1.000, p-value < 0.001). Based on the results obtained, this method can be a reliable tool for early phenotypic assignment, assessing diagnoses in patients with borderline GalA activity, and confirming non-relevant mutations of the GLA gene.

Pericardial effusion in the course of Fabry disease cardiomyopathy: a case report

Background

Fabry disease (FD) is an X-chromosome-linked inherited disorder of glycosphingolipid metabolism due to deficient or absent lysosomal α-galactosidase A activity.

Case summary

A 51-year-old Japanese woman with a previous diagnosis of FD presented with pericardial effusion. The exudative pericardial fluid contained globotriaosylsphingosine. Left ventricular hypertrophy progressed despite regular administration of agalsidase alfa every 2 weeks over a 7-year period, with increases in plasma levels of globotriaosylsphingosine and interleukin (IL)-18. In addition, the IL-6 level in the pericardial fluid was markedly higher than that in plasma.

Discussion

This case suggests that elevated IL-6 and IL-18 levels in pericardial fluid and plasma indicate the severity of FD cardiomyopathy.

LC-MS lipidomics of renal biopsies for the diagnosis of Fabry disease

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Fabry is an X-linked lysosomal storage disease with deficiency in α-galactosidase.

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This deficiency results in the accumulation of glycosphinogolipids.

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Diagnosis is often made by analysis of globotriaosylceramide in fluids and tissues.

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Fabry is often misdiagnosed in female patients due to residual enzyme activity.

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Lipidomics by LC-HRMS enables identification of new biomarkers in Fabry.

Introduction

Lipidomics analysis or lipid profiling is a system-based analysis of all lipids in a sample to provide a comprehensive understanding of lipids within a biological system. In the last few years, lipidomics has made it possible to better understand the metabolic processes associated with several rare disorders and proved to be a powerful tool for their clinical investigation. Fabry disease is a rare X-linked lysosomal storage disorder (LSD) caused by a deficiency in α-galactosidase A (α-GAL A). This deficiency results in the progressive accumulation of glycosphingolipids, mostly globotriaosylceramide (Gb₃), globotriaosylsphingosine (lyso-Gb₃), as well as galabiosylceramide (Ga₂) and their isoforms/analogs in the vascular endothelium, nerves, cardiomyocytes, renal glomerular podocytes, and biological fluids.

Objectives

The primary objective of this study was to evaluate lipidomic signatures in renal biopsies to help understand variations in Fabry disease markers that could be used in future diagnostic tests.

Methods

Lipidomic analysis was performed by ultra-high pressure liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) on kidney biopsies that were left over after clinical pathology analysis to diagnose Fabry disease.

Results

We employed UHPLC-HRMS lipidomics analysis on the renal biopsy of a patient suspicious for Fabry disease. Our result confirmed α-GAL A enzyme activity declined in this patient since a Ga2-related lipid biomarker was substantially higher in the patient's renal tissue biopsy compared with two controls. This suggests this patient has a type of LSD that could be non-classical Fabry disease.

Conclusion

This study shows that lipidomics analysis is a valuable tool for rare disorder diagnosis, which can be conducted on leftover tissue samples without disrupting normal patient care.

Comparative urinary globotriaosylceramide analysis by thin-layer chromatography-immunostaining and liquid chromatography-tandem mass spectrometry in patients with Fabry disease

In Fabry disease, accumulation of glycolipids, predominantly globotriaosylceramide (Gb3), affects the kidneys, and nephropathy is one of the important disorders that influence the disease severity and prognosis of patients. Urinary Gb3 has been analyzed for diagnosis and monitoring of Fabry disease. In this study, we analyzed urinary Gb3 by thin-layer chromatography (TLC)-immunostaining and liquid chromatography (LC)-tandem mass spectrometry (MS/MS). An improved qualitative method, TLC-immunostaining, revealed excessive urinary Gb3 excretion in 100 (8/8), 88 (14/16), and 74% (45/61) of the classic Fabry males, later-onset Fabry males, and Fabry females examined, respectively. This authentic method is robust, easy, economic, and hardly affected by abundant urinary sediment, and this is useful for diagnosing individual Fabry patients. LC-MS/MS can determine the level of Gb3 in urine with high sensitivity, and it revealed that the Gb3 excretion level was higher in the order of classic Fabry males, later-onset Fabry males, Fabry females, and controls, respectively, and this is expected to be a useful quantitative method not only for diagnosis but also for predicting the progression of Fabry nephropathy. As to the relation of the urinary Gb3 level and renal events, our study revealed that the urinary Gb3 level in Fabry patients experiencing renal events tended to be higher than that in ones who did not have any renal events in each phenotypic group of the disease.

Value of Left Ventricular Feature Tracking Strain Analysis for Detection of Early Cardiac Involvement in Fabry Disease (FD)

Purpose: Detection of cardiac involvement in Fabry disease (FD) is of high importance for treatment management. Native T1 mapping especially showed great potential for detection of early cardiac manifestations. Echocardiographic studies showed strain abnormalities in FD patients, but data on MRI feature tracking strain analysis (FT-SA) is limited. Therefore, the aim of our study was to evaluate the potential of FT-SA compared to native T1 and the FD specific biomarker Globotriaosylsphingosine (LysoGb3). Methods: 28 consecutive FD patients (18 female; 47.8 years ± 17.4 standard deviation (SD)) and 28 control subjects (18 female; 46.6 years ± 18.2 SD) underwent cardiac MRI at 1.5 Tesla. Global native T1 times and left ventricular FT-SA were evaluated. Results were correlated to serum Lyso-Gb3-levels. Results: Native T1 times, global longitudinal (GLS) and global radial strain (GRS) were significantly reduced in FD patients (p < 0.0064, p = 0.0009 and p = 0.0184, respectively). Moreover, native T1 times and GLS were significantly lower in Lyso-Gb3 positive FD patients (p < 0.005 and p = 0.03). GLS, native T1 times showed significant moderate correlations to LysoGb3 (p = 0.002 and p < 0.001). Furthermore, GLS and native T1 times reduce when LysoGb3 was elevated and increasingly with presence of left ventricular hypertrophy (LVH) or late gadolinium enhancement (LGE). Conclusions: Native T1 times and strain values differ significantly between FD patients and control subjects and showed promising correlations to the FD specific biomarker LysoGb3. We therefore conclude that strain abnormalities occur early beside native T1 reductions in cardiac FD involvement. Large scale trials are needed to verify our findings.

Biomarkers of Fabry Nephropathy: Review and Future Perspective

Progressive nephropathy is one of the main features of Fabry disease, which largely contributes to the overall morbidity and mortality burden of the disease. Due to the lack of specific biomarkers, the heterogeneity of the disease, and unspecific symptoms, diagnosis is often delayed. Clinical presentation in individual patients varies widely, even in patients from the same family carrying the same pathogenic GLA variant. Therefore, it is reasonable to anticipate that additional genomic, transcriptomic, proteomic, and metabolomics factors influence the manifestation and progression of the disease. The aim of this article is to provide an overview of nephropathy in Fabry patients and the biomarkers currently used in the diagnosis and follow-up. Current biomarkers are associated with late signs of kidney damage. Therefore, there is a need to identify biomarkers associated with early stages of kidney damage that would enable early diagnosis, which is crucial for effective treatment and prevention of severe irreversible complications. Recent advances in sequencing and -omics technologies have led to several studies investigating new biomarkers. We will provide an overview of the novel biomarkers, critically evaluate their clinical utility, and propose future perspectives, which we believe might be in their integration.

An expert consensus document on the management of cardiovascular manifestations of Fabry disease

Fabry disease (FD) is an X-linked lysosomal storage disorder caused by pathogenic variants in the α-galactosidase A (GLA) gene that leads to reduced or undetectable α-galactosidase A enzyme activity and progressive accumulation of globotriaosylceramide and its deacylated form globotriaosylsphingosine in cells throughout the body. FD can be multisystemic with neurological, renal, cutaneous and cardiac involvement or be limited to the heart. Cardiac involvement is characterized by progressive cardiac hypertrophy, fibrosis, arrhythmias, heart failure and sudden cardiac death. The cardiac management of FD requires specific measures including enzyme replacement therapy or small pharmacological chaperones in patients carrying amenable pathogenic GLA gene variants and more general management of cardiac symptoms and complications. In this paper, we summarize current knowledge of FD-related heart disease and expert consensus recommendations for its management.

Pompe disease: pathogenesis, molecular genetics and diagnosis

Pompe disease (PD) is a rare autosomal recessive disorder caused by mutations in the GAA gene, localized on chromosome 17 and encoding for acid alpha-1,4-glucosidase (GAA). Currently, more than 560 mutations spread throughout GAA gene have been reported. GAA catalyzes the hydrolysis of α-1,4 and α-1,6-glucosidic bonds of glycogen and its deficiency leads to lysosomal storage of glycogen in several tissues, particularly in muscle. PD is a chronic and progressive pathology usually characterized by limb-girdle muscle weakness and respiratory failure. PD is classified as infantile and childhood/adult forms. PD patients exhibit a multisystemic manifestation that depends on age of onset.

Early diagnosis is essential to prevent or reduce the irreversible organ damage associated with PD progression. Here, we make an overview of PD focusing on pathogenesis, clinical phenotypes, molecular genetics, diagnosis, therapies, autophagy and the role of miRNAs as potential biomarkers for PD.

Novel biomarkers for lysosomal storage disorders: Metabolomic and proteomic approaches

Lysosomal storage disorders (LSDs) are characterized by the accumulation of specific disease substrates inside the lysosomes of various cells, eventually leading to the deterioration of cellular function and multisystem organ damage. With the continuous discovery and validation of novel and advanced therapies for most LSDs, there is an urgent need to discover more versatile and clinically relevant biomarkers. The utility of these biomarkers should ideally extend beyond the screening and diagnosis of LSDs to the evaluation of disease severity and monitoring of therapy. Metabolomic and proteomic approaches provide the means to the discovery and validation of such novel biomarkers. This is achieved mainly through the application of various mass spectrometric techniques to common and easily accessible biological samples, such as plasma, urine and dried blood spots. In this review, we tried to summarize the complexity of the lysosomal disorders phenotypes, their current diagnostic and therapeutic approaches, the various techniques supporting metabolomic and proteomic studies and finally we tried to explore the newly discovered biomarkers for most LSDs and their reported clinical values.

Altered Sphingolipids Metabolism Damaged Mitochondrial Functions: Lessons Learned From Gaucher and Fabry Diseases

Sphingolipids represent a class of bioactive lipids that modulate the biophysical properties of biological membranes and play a critical role in cell signal transduction. Multiple studies have demonstrated that sphingolipids control crucial cellular functions such as the cell cycle, senescence, autophagy, apoptosis, cell migration, and inflammation. Sphingolipid metabolism is highly compartmentalized within the subcellular locations. However, the majority of steps of sphingolipids metabolism occur in lysosomes. Altered sphingolipid metabolism with an accumulation of undigested substrates in lysosomes due to lysosomal enzyme deficiency is linked to lysosomal storage disorders (LSD). Trapping of sphingolipids and their metabolites in the lysosomes inhibits lipid recycling, which has a direct effect on the lipid composition of cellular membranes, including the inner mitochondrial membrane. Additionally, lysosomes are not only the house of digestive enzymes, but are also responsible for trafficking organelles, sensing nutrients, and repairing mitochondria. However, lysosomal abnormalities lead to alteration of autophagy and disturb the energy balance and mitochondrial function. In this review, an overview of mitochondrial function in cells with altered sphingolipid metabolism will be discussed focusing on the two most common sphingolipid disorders, Gaucher and Fabry diseases. The review highlights the status of mitochondrial energy metabolism and the regulation of mitochondria-autophagy-lysosome crosstalk.

Metabolomic Studies of Lipid Storage Disorders, with Special Reference to Niemann-Pick Type C Disease: A Critical Review with Future Perspectives

Lysosomal storage disorders (LSDs) are predominantly very rare recessive autosomal neurodegenerative diseases.Sphingolipidoses, a sub-group of LSDs, result from defects in lysosomal enzymes involved in sphingolipid catabolism, and feature disrupted storage systems which trigger complex pathogenic cascades with other organelles collaterally affected. This process leads to cell dysfunction and death, particularly in the central nervous system. One valuable approach to gaining insights into the global impact of lysosomal dysfunction is through metabolomics, which represents a discovery tool for investigating disease-induced modifications in the patterns of large numbers of simultaneously-analysed metabolites, which also features the identification of biomarkers Here, the scope and applications of metabolomics strategies to the investigation of sphingolipidoses is explored in order to facilitate our understanding of the biomolecular basis of these conditions. This review therefore surveys the benefits of applying ’state-of-the-art’ metabolomics strategies, both univariate and multivariate, to sphingolipidoses, particularly Niemann-Pick type C disease. Relevant limitations of these techniques are also discussed, along with the latest advances and developments. We conclude that metabolomics strategies are highly valuable, distinctive bioanalytical techniques for probing LSDs, most especially for the detection and validation of potential biomarkers. They also show much promise for monitoring disease progression and the evaluation of therapeutic strategies and targets.

Fabry Disease with Pacemaker Implantation as the Initial Event

Fabry disease (FD) is a rare X-linked hereditary disorder (Xq22) caused by a deficiency in alpha-galactosidase activity. A 34-year-old man was referred to our hospital because of renal dysfunction. He had previously undergone pacemaker implantation at 24 years of age. Investigations revealed undetectable alpha-galactosidase A activity levels. Renal biopsy results indicated vacuolization of podocytes. A genetic analysis revealed that the patient carried the W340X mutation. Enzyme replacement therapy with agalsidase beta was started. This case is novel because most cases of FD nephropathy precede cardiac disease. In our patient, the cardiac event was the initial event, and renal impairment followed.

Systemic mRNA Therapy for the Treatment of Fabry Disease: Preclinical Studies in Wild-Type Mice, Fabry Mouse Model, and Wild-Type Non-human Primates

Fabry disease is an X-linked lysosomal storage disease caused by loss of alpha galactosidase A (α-Gal A) activity and is characterized by progressive accumulation of globotriaosylceramide and its analogs in all cells and tissues. Although enzyme replacement therapy (ERT) is considered standard of care, the long-term effects of ERT on renal and cardiac manifestations remain uncertain and thus novel therapies are desirable. We herein report preclinical studies evaluating systemic messenger RNA (mRNA) encoding human α-Gal A in wild-type (WT) mice, α-Gal A-deficient mice, and WT non-human primates (NHPs). The pharmacokinetics and distribution of h-α-Gal A mRNA encoded protein in WT mice demonstrated prolonged half-lives of α-Gal A in tissues and plasma. Single intravenous administration of h-α-Gal A mRNA to Gla-deficient mice showed dose-dependent protein activity and substrate reduction. Moreover, long duration (up to 6 weeks) of substrate reductions in tissues and plasma were observed after a single injection. Furthermore, repeat i.v. administration of h-α-Gal A mRNA showed a sustained pharmacodynamic response and efficacy in Fabry mice model. Lastly, multiple administrations to non-human primates confirmed safety and translatability. Taken together, these studies across species demonstrate preclinical proof-of-concept of systemic mRNA therapy for the treatment of Fabry disease and this approach may be useful for other lysosomal storage disorders.

Fabry disease in a Japanese population-molecular and biochemical characteristics

We had experienced 117 Japanese Fabry patients (72 males and 45 females) from 1977 to 2006, and then we generated an improved Fabry analysis system in 2007 and have found 196 ones (95 males and 101 females) since then. In this study, we summarized the data of the patients and tried to elucidate the molecular and biochemical characteristics of Japanese Fabry patients. Gene analysis revealed various GLA mutations, including missense mutations (56.5%, 48 types); nonsense mutations (15.9%, 13 types); deletions (12.6%, 13 types); splicing defects (10.1%, 6 types); insertions (1.0%, 2 types), and insertions/deletions (0.5%, 1 type), in the patients that were tested. Amino acid substitutions resulting from the missense mutations found in the classic form patients tended to be localized in the core of the GLA protein, and those in the later-onset ones in the peripheral region. The most commonly identified pathogenic mutations are c.888G > A (p.M296I), c.936 + 919G > A, c.679C > T (p.R227X), c.335G > A (p.R112H), c.334C > T (p.R112C), and c.902G > A (p.R301Q). Among them, c.888G > A (p.M296I) is unique to Japanese Fabry patients. On the other hand, c.936 + 919G > A is a variant that has been frequently detected in Taiwan Chinese Fabry patients, and c.335G > A (p.R112H) in various countries. These are found in later-onset patients, and c.679C > T (p.R227X) and c.334C > T (p.R112C) classic ones. c.902G > A (p.R301Q) is found in both classic and later-onset form patients. A possible functional polymorphism, c.196G > C (p.E66Q), was identified in 0.4% of the subjects who underwent high-risk screening. The biochemical findings including leukocyte α-galactosidase A activity, plasma globotriaosylsphingosine level and urinary globotriaosylceramide in the individual phenotypic groups well reflected the phenotypic differences in this disease. The results will be useful for understanding the basis of Fabry disease in Japan.

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The characteristics of Japanese Fabry patients were elucidated.

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p.M296I unique to Japanese Fabry patients was commonly identified.

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The biochemical findings well reflected the phenotypic differences.

Rapid screening for lipid storage disorders using biochemical markers. Expert center data and review of the literature

BACKGROUND

In patients suspected of a lipid storage disorder (sphingolipidoses, lipidoses), confirmation of the diagnosis relies predominantly on the measurement of specific enzymatic activities and genetic studies. New UPLC-MS/MS methods have been developed to measure lysosphingolipids and oxysterols, which, combined with chitotriosidase activity may represent a rapid first tier screening for lipid storage disorders.

MATERIAL AND METHODS

A lysosphingolipid panel consisting of lysoglobotriaosylceramide (LysoGb3), lysohexosylceramide (LysoHexCer: both lysoglucosylceramide and lysogalactosylceramide), lysosphingomyelin (LysoSM) and its carboxylated analogue lysosphingomyelin-509 (LysoSM-509) was measured in control subjects and plasma samples of predominantly untreated patients affected with lipid storage disorders (n=74). In addition, the oxysterols cholestane-3β,5α,6β-triol and 7-ketocholesterol were measured in a subset of these patients (n=36) as well as chitotriosidase activity (n=43). A systematic review of the literature was performed to assess the usefulness of these biochemical markers.

RESULTS

Specific elevations of metabolites, i.e. without overlap between controls and other lipid storage disorders, were found for several lysosomal storage diseases: increased LysoSM levels in acid sphingomyelinase deficiency (Niemann-Pick disease type A/B), LysoGb3 levels in males with classical phenotype Fabry disease and LysoHexCer (i.e. lysoglucosylceramide/lysogalactosylceramide) in Gaucher and Krabbe diseases. While elevated levels of LysoSM-509 and cholestane-3β,5α,6β-triol did not discriminate between Niemann Pick disease type C and acid sphingomyelinase deficiency, LysoSM-509/LysoSM ratio was specifically elevated in Niemann-Pick disease type C. In Gaucher disease type I, mild increases in several lysosphingolipids were found including LysoGb3 with levels in the range of non-classical Fabry males and females. Chitotriosidase showed specific elevations in symptomatic Gaucher disease, and was mildly elevated in all other lipid storage disorders. Review of the literature identified 44 publications. Most findings were in line with our cohort. Several moderate elevations of biochemical markers were found across a wide range of other, mainly inherited metabolic, diseases.

CONCLUSION

Measurement in plasma of LysoSLs and oxysterols by UPLC-MS/MS in combination with activity of chitotriosidase provides a useful first tier screening of patients suspected of lipid storage disease. The LysoSM-509/LysoSM ratio is a promising parameter in Niemann-Pick disease type C. Further studies in larger groups of untreated patients and controls are needed to improve the specificity of the findings.

Lipid biomarkers for the peroxisomal and lysosomal disorders: their formation, metabolism and measurement

Lipid biomarkers play important roles in the diagnosis of and monitoring of treatment in peroxisomal disorders and lysosomal storage disorders. Today, a variety of lipids, including very long chain fatty acids, glycolipids, bile acids and the oxidation products of cholesterol, have been considered as biomarkers for these disorders. In this brief review, the authors summarized the recent advances regarding these lipid biomarkers in terms of their formation, metabolism and measurement in these disorders. An understanding of these biomarkers will offer a key to the development of novel diagnoses and help create more effective therapies in the future.

Plasma lyso-Gb3: a biomarker for monitoring fabry patients during enzyme replacement therapy

BACKGROUND

Recently, globotriaosylsphingosine (lyso-Gb3) has attracted interest as a biomarker of Fabry disease. However, little is known regarding its utility for the evaluation of the therapeutic efficacy.

METHOD

We measured plasma lyso-Gb3 concentration in Japanese healthy subjects and Fabry patients by means of liquid chromatography-tandem mass spectrometry (LC-MS/MS). We determined the reference interval in Japanese (UMIN000016854), and examined the effect of enzyme replacement therapy (ERT) with recombinant α-galactosidase A (GLA) and the influence of antibodies against the enzyme on the plasma lyso-Gb3 level in Fabry patients (UMIN000017152).

RESULTS

The reference interval was determined to be 0.35-0.71 nmol/L, this being almost the same as the normal range in a non-Japanese population previously reported. The analysis revealed that the plasma lyso-Gb3 level was strikingly increased in classic Fabry males, and to a lesser extent in later-onset Fabry males and Fabry females. The elevation of the plasma lyso-Gb3 level was related to renal involvement in the Fabry females. ERT gave a rapid reduction in the elevated plasma lyso-Gb3 level in the classic Fabry males, and a gradual one or stabilization in most of the later-onset Fabry males and Fabry females. However, formation of antibodies against the recombinant GLA had a negative effect on the reduction of plasma lyso-Gb3.

CONCLUSIONS

Regular observation of plasma lyso-Gb3 and antibodies is useful for monitoring of Fabry patients during ERT.

Biomarkers and Imaging Findings of Anderson-Fabry Disease-What We Know Now

Anderson–Fabry disease (AFD) is an X-linked lysosomal storage disorder, caused by deficiency or absence of the alpha-galactosidase A activity, with a consequent glycosphingolipid accumulation. Biomarkers and imaging findings may be useful for diagnosis, identification of an organ involvement, therapy monitoring and prognosis. The aim of this article is to review the current available literature on biomarkers and imaging findings of AFD patients. An extensive bibliographic review from PubMed, Medline and Clinical Key databases was performed by a group of experts from nephrology, neurology, genetics, cardiology and internal medicine, aiming for consensus. Lyso-GB3 is a valuable biomarker to establish the diagnosis. Proteinuria and creatinine are the most valuable to detect renal damage. Troponin I and high-sensitivity assays for cardiac troponin T can identify patients with cardiac lesions, but new techniques of cardiac imaging are essential to detect incipient damage. Specific cerebrovascular imaging findings are present in AFD patients. Techniques as metabolomics and proteomics have been developed in order to find an AFD fingerprint. Lyso-GB3 is important for evaluating the pathogenic mutations and monitoring the response to treatment. Many biomarkers can detect renal, cardiac and cerebrovascular involvement, but none of these have proved to be important to monitoring the response to treatment. Imaging features are preferred in order to find cardiac and cerebrovascular compromise in AFD patients.

The severe clinical phenotype for a heterozygous Fabry female patient correlates to the methylation of non-mutated allele associated with chromosome 10q26 deletion syndrome

Heterozygous Fabry females usually have an attenuated form of Fabry disease, causing them to be symptomatic; however, in rare cases, they can present with a severe phenotype. In this study, we report on a 37-year-old woman with acroparesthesia, a dysmorphic face, left ventricular hypertrophy, and intellectual disability. Her father had Fabry disease and died due to chronic renal and congestive cardiac failure. Her paternal uncle had chronic renal failure and intellectual disability, and her paternal aunt was affected with congestive cardiac failure. The patient has two sisters with no significant medical illness. However, her nephew has acroparesthesia, anhidrosis, and school phobia, and her niece shows mild phenotypes. The patient's enzyme analysis showed very low α-galactosidase A (α-gal A) activity in dried blood spot (DBS), lymphocytes, and skin fibroblasts with massive excretion of Gb3 and Gb2 in urine and lyso-Gb3 in DBS and plasma. Electron microscopic examination showed a large accumulation of sphingolipids in vascular endothelial cells and keratinocytes. Chromosomal analysis and comparative genomic hybridization microarray showed 10q26 terminal deletion. Molecular data showed a novel heterozygous stop codon mutation in exon 1 of the GLA gene in her sisters and niece, and a hemizygous state in her nephew. When we checked the methylation status, we found her non-mutated allele in the GLA gene was methylated. However, the non-mutated alleles of her sisters were non-methylated, and those of her niece were partially methylated. The chromosomal and methylation study may speculate the severity of her clinical phenotypes.

Differences in cleavage of globotriaosylceramide and its derivatives accumulated in organs of young Fabry mice following enzyme replacement therapy

In Fabry disease, large amounts of globotriaosylceramide (Gb3) and related glycosphingolipids accumulate in organs due to a deficiency of α-galactosidase A (GLA) activity. Enzyme replacement therapy (ERT) with recombinant GLA is now available, and it has been reported that ERT is beneficial for patients with Fabry disease, especially those who start treatment at an early stage of the disease. However, it seems that the efficacy of ERT differs with each organ, and Gb3 accumulated in the kidneys shows resistance to ERT when it is started at a late stage. In this study, we examined the differences in cleavage of Gb3 isoforms, and lyso-Gb3 and its analogues in the kidneys, liver, and heart in young Fabry mice subjected to ERT. The results revealed that recurrent administration of recombinant GLA had prominent effects in terms of degradation of Gb3 and its derivatives accumulated in the organs. However, particular Gb3 isoforms, i.e., Gb3 (C20:0) and Gb3 (C24OH), accumulated in the kidneys largely escaped from degradation. Such Gb3 isoforms may gradually accumulate in the kidneys from a young age, which results in a reduction in the efficacy of ERT for Fabry disease.

Tandem Mass Spectrometry of Sphingolipids: Applications for Diagnosis of Sphingolipidoses

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: 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.

Distributions of Globotriaosylceramide Isoforms, and Globotriaosylsphingosine and Its Analogues in an α-Galactosidase A Knockout Mouse, a Model of Fabry Disease

Fabry disease is caused by deficient activity of α-galactosidase A (GLA) and characterized by systemic accumulation of glycosphingolipids, substrates of the enzyme. To gain insight into the pathogenesis of Fabry disease based on accumulated substrates, we examined the tissue and plasma distributions of globotriaosylceramide (Gb3) isoforms, and globotriaosylsphingosine (lyso-Gb3) and its analogues in a GLA knockout mouse, a model of Fabry disease, by means of liquid chromatography-mass spectrometry and nano-liquid chromatography-tandem mass spectrometry, respectively. The results revealed that the contents of these substrates in the liver, kidneys, heart, and plasma of GLA knockout mice were apparently higher than in those of wild-type ones, and organ specificity in the accumulation of Gb3 isoforms was found. Especially in the kidneys, accumulation of a large amount of Gb3 isoforms including hydroxylated residues was found. In the GLA knockout mice, the proportion of hydrophobic Gb3 isoforms was apparently higher than that in the wild-type mice. On the other hand, hydrophilic residues were abundant in plasma. Unlike that of Gb3, the concentration of lyso-Gb3 was high in the liver, and the lyso-Gb3/Gb3 ratio in plasma was significantly higher than those in the organs. The concentration of lyso-Gb3 was apparently higher than those of its analogues in the organs and plasma from both the GLA knockout and wild-type mice. This information will be useful for elucidating the basis of Fabry disease.